파이썬 설명서 목차

파이썬의 새로운 기능

What’s new in Python 3.14

Summary – release highlights

New features

PEP 649: deferred evaluation of annotations

Implications for annotated code

Implications for readers of __annotations__

Related changes

from __future__ import annotations

Improved error messages

PEP 741: Python Configuration C API

Other language changes

New modules

Improved modules

argparse

ast

concurrent.futures

ctypes

datetime

decimal

dis

fractions

functools

getopt

http

inspect

json

mimetypes

multiprocessing

operator

os

pathlib

pdb

platform

pickle

pydoc

symtable

sys

unicodedata

unittest

uuid

Optimizations

asyncio

io

Deprecated

Pending removal in Python 3.15

Pending removal in Python 3.16

Pending removal in future versions

Removed

argparse

ast

asyncio

collections.abc

email

importlib

itertools

pathlib

pkgutil

pty

sqlite3

typing

urllib

Others

Porting to Python 3.14

Changes in the Python API

Build changes

PEP 761: Discontinuation of PGP signatures

C API changes

New features

Porting to Python 3.14

Deprecated

Pending removal in Python 3.15

Pending removal in future versions

Removed

What’s New In Python 3.13

Summary – Release Highlights

New Features

A better interactive interpreter

Improved error messages

Free-threaded CPython

An experimental just-in-time (JIT) compiler

Defined mutation semantics for locals()

Support for mobile platforms

Other Language Changes

New Modules

Improved Modules

argparse

array

ast

asyncio

base64

compileall

concurrent.futures

configparser

copy

ctypes

dbm

dis

doctest

email

fractions

glob

importlib

io

ipaddress

itertools

marshal

math

mimetypes

mmap

multiprocessing

os

os.path

pathlib

pdb

queue

random

re

shutil

site

sqlite3

ssl

statistics

subprocess

sys

tempfile

time

tkinter

traceback

types

typing

unicodedata

venv

warnings

xml

zipimport

Optimizations

Removed Modules And APIs

PEP 594: Remove “dead batteries” from the standard library

2to3

builtins

configparser

importlib.metadata

locale

opcode

pathlib

re

tkinter.tix

turtle

typing

unittest

urllib

webbrowser

New Deprecations

Pending removal in Python 3.14

Pending removal in Python 3.15

Pending removal in Python 3.16

Pending removal in future versions

CPython Bytecode Changes

C API Changes

New Features

Changed C APIs

Limited C API Changes

Removed C APIs

Deprecated C APIs

Pending removal in Python 3.14

Pending removal in Python 3.15

Pending removal in future versions

Build Changes

Porting to Python 3.13

Changes in the Python API

Changes in the C API

Regression Test Changes

What’s New In Python 3.12

Summary – Release highlights

New Features

PEP 695: Type Parameter Syntax

PEP 701: Syntactic formalization of f-strings

PEP 684: A Per-Interpreter GIL

PEP 669: Low impact monitoring for CPython

PEP 688: Making the buffer protocol accessible in Python

PEP 709: Comprehension inlining

Improved Error Messages

New Features Related to Type Hints

PEP 692: Using TypedDict for more precise **kwargs typing

PEP 698: Override Decorator for Static Typing

Other Language Changes

New Modules

Improved Modules

array

asyncio

calendar

csv

dis

fractions

importlib.resources

inspect

itertools

math

os

os.path

pathlib

pdb

random

shutil

sqlite3

statistics

sys

tempfile

threading

tkinter

tokenize

types

typing

unicodedata

unittest

uuid

Optimizations

CPython bytecode changes

Demos and Tools

Deprecated

Pending removal in Python 3.13

Pending removal in Python 3.14

Pending removal in Python 3.15

Pending removal in Python 3.16

Pending removal in future versions

Removed

asynchat and asyncore

configparser

distutils

ensurepip

enum

ftplib

gzip

hashlib

importlib

imp

io

locale

smtpd

sqlite3

ssl

unittest

webbrowser

xml.etree.ElementTree

zipimport

Others

Porting to Python 3.12

Changes in the Python API

Build Changes

C API Changes

New Features

Porting to Python 3.12

Deprecated

Pending removal in Python 3.14

Pending removal in Python 3.15

Pending removal in future versions

Removed

What’s New In Python 3.11

Summary – Release highlights

New Features

PEP 657: Fine-grained error locations in tracebacks

PEP 654: Exception Groups and except*

PEP 678: Exceptions can be enriched with notes

Windows py.exe launcher improvements

New Features Related to Type Hints

PEP 646: Variadic generics

PEP 655: Marking individual TypedDict items as required or not-required

PEP 673: Self type

PEP 675: Arbitrary literal string type

PEP 681: Data class transforms

PEP 563 may not be the future

Other Language Changes

Other CPython Implementation Changes

New Modules

Improved Modules

asyncio

contextlib

dataclasses

datetime

enum

fcntl

fractions

functools

gzip

hashlib

IDLE and idlelib

inspect

locale

logging

math

operator

os

pathlib

re

shutil

socket

sqlite3

string

sys

sysconfig

tempfile

threading

time

tkinter

traceback

typing

unicodedata

unittest

venv

warnings

zipfile

Optimizations

Faster CPython

Faster Startup

Frozen imports / Static code objects

Faster Runtime

Cheaper, lazy Python frames

Inlined Python function calls

PEP 659: Specializing Adaptive Interpreter

Misc

FAQ

How should I write my code to utilize these speedups?

Will CPython 3.11 use more memory?

I don’t see any speedups in my workload. Why?

Is there a JIT compiler?

About

CPython bytecode changes

New opcodes

Replaced opcodes

Changed/removed opcodes

Deprecated

Language/Builtins

Modules

Standard Library

Pending Removal in Python 3.12

Removed

Porting to Python 3.11

Build Changes

C API Changes

New Features

Porting to Python 3.11

Deprecated

Pending Removal in Python 3.12

Removed

Notable changes in 3.11.4

tarfile

Notable changes in 3.11.5

OpenSSL

What’s New In Python 3.10

Summary – Release highlights

New Features

Parenthesized context managers

Better error messages

SyntaxErrors

IndentationErrors

AttributeErrors

NameErrors

PEP 626: Precise line numbers for debugging and other tools

PEP 634: Structural Pattern Matching

Syntax and operations

Declarative approach

Simple pattern: match to a literal

Behavior without the wildcard

Patterns with a literal and variable

Patterns and classes

Patterns with positional parameters

Nested patterns

Complex patterns and the wildcard

Guard

Other Key Features

Optional EncodingWarning and encoding="locale" option

New Features Related to Type Hints

PEP 604: New Type Union Operator

PEP 612: Parameter Specification Variables

PEP 613: TypeAlias

PEP 647: User-Defined Type Guards

Other Language Changes

New Modules

Improved Modules

asyncio

argparse

array

asynchat, asyncore, smtpd

base64

bdb

bisect

codecs

collections.abc

contextlib

curses

dataclasses

__slots__

Keyword-only fields

distutils

doctest

encodings

enum

fileinput

faulthandler

gc

glob

hashlib

hmac

IDLE and idlelib

importlib.metadata

inspect

itertools

linecache

os

os.path

pathlib

platform

pprint

py_compile

pyclbr

shelve

statistics

site

socket

ssl

sqlite3

sys

_thread

threading

traceback

types

typing

unittest

urllib.parse

xml

zipimport

Optimizations

Deprecated

Removed

Porting to Python 3.10

Changes in the Python syntax

Changes in the Python API

Changes in the C API

CPython bytecode changes

Build Changes

C API Changes

PEP 652: Maintaining the Stable ABI

New Features

Porting to Python 3.10

Deprecated

Removed

Notable security feature in 3.10.7

Notable security feature in 3.10.8

Notable changes in 3.10.12

tarfile

파이썬 3.9의 새로운 기능

요약 – 배포 주요 사항

여러분의 코드에서 DeprecationWarning을 확인해야합니다

새로운 기능

딕셔너리 병합과 업데이트 연산자

접두사와 접미사를 제거하는 새로운 문자열 메서드

표준 컬렉션의 형 힌트 제네릭

새로운 구문 분석기

기타 언어 변경

새 모듈

zoneinfo

graphlib

개선된 모듈

ast

asyncio

compileall

concurrent.futures

curses

datetime

distutils

fcntl

ftplib

gc

hashlib

http

IDLE과 idlelib

imaplib

importlib

inspect

ipaddress

math

multiprocessing

nntplib

os

pathlib

pdb

poplib

pprint

pydoc

random

signal

smtplib

socket

time

sys

tracemalloc

typing

unicodedata

venv

xml

최적화

폐지

제거

파이썬 3.9로 이식하기

파이썬 API의 변경

C API의 변경

CPython 바이트 코드 변경

빌드 변경

C API 변경

새로운 기능

파이썬 3.9로 이식하기

제거

파이썬 3.9.1의 주목할만한 변경 사항

typing

macOS 11.0 (Big Sur) 및 Apple Silicon Mac 지원

파이썬 3.9.2의 주목할만한 변경 사항

collections.abc

urllib.parse

파이썬 3.9.3의 주목할만한 변경 사항

Notable changes in Python 3.9.5

urllib.parse

Notable security feature in 3.9.14

Notable changes in 3.9.17

tarfile

파이썬 3.8의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

대입 표현식

위치 전용 매개 변수

컴파일된 바이트 코드 파일을 위한 병렬 파일 시스템 캐시

디버그 빌드는 릴리스 빌드와 같은 ABI를 사용합니다.

f-문자열은 스스로 설명하는 표현식과 디버깅을 위해 =를 지원합니다.

PEP 578: 파이썬 런타임 감사 훅

PEP 587: 파이썬 초기화 구성

PEP 590: 벡터콜: CPython을 위한 빠른 호출 프로토콜

아웃 오브 밴드 데이터 버퍼를 사용하는 피클 프로토콜 5

기타 언어 변경

새 모듈

개선된 모듈

ast

asyncio

builtins

collections

cProfile

csv

curses

ctypes

datetime

functools

gc

gettext

gzip

IDLE과 idlelib

inspect

io

itertools

json.tool

logging

math

mmap

multiprocessing

os

os.path

pathlib

pickle

plistlib

pprint

py_compile

shlex

shutil

socket

ssl

statistics

sys

tarfile

threading

tokenize

tkinter

time

typing

unicodedata

unittest

venv

weakref

xml

xmlrpc

최적화

빌드와 C API 변경

폐지

API 및 기능 제거

파이썬 3.8로 이식하기

파이썬 동작의 변경

파이썬 API의 변경

C API의 변경

CPython 바이트 코드 변경

데모와 도구

파이썬 3.8.1의 주목할만한 변경 사항

Notable changes in Python 3.8.2

Notable changes in Python 3.8.3

파이썬 3.8.8의 주목할만한 변경 사항

Notable changes in Python 3.8.9

Notable changes in Python 3.8.10

macOS 11.0 (Big Sur) and Apple Silicon Mac support

Notable changes in Python 3.8.10

urllib.parse

Notable changes in Python 3.8.12

파이썬 API의 변경

Notable security feature in 3.8.14

Notable changes in 3.8.17

tarfile

파이썬 3.7의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

PEP 563 : 어노테이션의 지연된 평가

PEP 538: 레거시 C 로케일 강제 변경

PEP 540: 강제 UTF-8 실행시간 모드

PEP 553: 내장 breakpoint()

PEP 539: 스레드-로컬 저장소를 위한 새로운 C API

PEP 562: 모듈 어트리뷰트에 대한 액세스 사용자 정의

PEP 564: 나노초 해상도의 새로운 시간 함수

PEP 565: __main__ 의 DeprecationWarning 표시

PEP 560: typing 모듈과 제네릭 형에 대한 코어 지원

PEP 552: 해시 기반 .pyc 파일

PEP 545: 파이썬 설명서 번역

파이썬 개발 모드 (-X dev)

기타 언어 변경

새 모듈

contextvars

dataclasses

importlib.resources

개선된 모듈

argparse

asyncio

binascii

calendar

collections

compileall

concurrent.futures

contextlib

cProfile

crypt

datetime

dbm

decimal

dis

distutils

enum

functools

gc

hmac

http.client

http.server

idlelib 및 IDLE

importlib

io

ipaddress

itertools

locale

logging

math

mimetypes

msilib

multiprocessing

os

pathlib

pdb

py_compile

pydoc

queue

re

signal

socket

socketserver

sqlite3

ssl

string

subprocess

sys

time

tkinter

tracemalloc

types

unicodedata

unittest

unittest.mock

urllib.parse

uu

uuid

warnings

xml

xml.etree

xmlrpc.server

zipapp

zipfile

C API 변경

빌드 변경

최적화

기타 CPython 구현 변경

폐지된 파이썬 동작

폐지된 파이썬 모듈, 함수 및 메서드

aifc

asyncio

collections

dbm

enum

gettext

importlib

locale

macpath

threading

socket

ssl

sunau

sys

wave

폐지된 C API의 함수 및 형

플랫폼 지원 제거

API 및 기능 제거

모듈 제거

윈도우 전용 변경

파이썬 3.7로 이식하기

파이썬 동작의 변경

파이썬 API의 변경

C API의 변경

CPython 바이트 코드 변경

윈도우 전용 변경

기타 CPython 구현 변경

파이썬 3.7.1의 주목할만한 변경 사항

파이썬 3.7.2의 주목할만한 변경 사항

파이썬 3.7.6의 주목할만한 변경 사항

파이썬 3.7.10의 주목할만한 변경 사항

Notable changes in Python 3.7.11

Notable security feature in 3.7.14

파이썬 3.6의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

PEP 498: 포맷 문자열 리터럴

PEP 526: 변수 어노테이션 문법

PEP 515: 숫자 리터럴의 밑줄

PEP 525: 비동기 제너레이터

PEP 530: 비동기 컴프리헨션

PEP 487: 더 간단한 클래스 생성 사용자 정의

PEP 487: 디스크립터 프로토콜 향상

PEP 519: 파일 시스템 경로 프로토콜 추가

PEP 495: 현지 시간 명확성

PEP 529: 윈도우 파일 시스템 인코딩을 UTF-8로 변경

PEP 528: 윈도우 콘솔 인코딩을 UTF-8로 변경

PEP 520: 클래스 어트리뷰트 정의 순서 유지

PEP 468: 키워드 인자 순서 유지

새로운 dict 구현

PEP 523: CPython에 프레임 평가 API 추가

PYTHONMALLOC 환경 변수

DTrace와 SystemTap 프로브 지원

기타 언어 변경

새로운 모듈

secrets

개선된 모듈

array

ast

asyncio

Binascii

cmath

collections

concurrent.futures

contextlib

datetime

decimal

distutils

email

encodings

enum

faulthandler

fileinput

hashlib

http.client

idlelib와 IDLE

importlib

inspect

json

logging

math

multiprocessing

os

pathlib

pdb

pickle

pickletools

pydoc

random

re

readline

rlcompleter

shlex

site

sqlite3

socket

socketserver

ssl

statistics

struct

subprocess

sys

telnetlib

time

timeit

tkinter

traceback

tracemalloc

typing

unicodedata

unittest.mock

urllib.request

urllib.robotparser

venv

warnings

winreg

winsound

xmlrpc.client

zipfile

zlib

최적화

빌드와 C API 변경

기타 개선 사항

폐지

새 키워드

폐지된 파이썬 동작

폐지된 파이썬 모듈, 함수 및 메서드

asynchat

asyncore

dbm

distutils

grp

importlib

os

re

ssl

tkinter

venv

xml

C API의 폐지된 함수와 형

폐지된 빌드 옵션

제거

API와 기능 제거

파이썬 3.6으로 이식하기

‘python’ 명령 동작의 변경 사항

파이썬 API의 변경 사항

C API의 변경 사항

CPython 바이트 코드 변경 사항

파이썬 3.6.2의 주목할만한 변경 사항

새로운 make regen-all 빌드 대상

make touch 빌드 대상 제거

파이썬 3.6.4의 주목할만한 변경 사항

파이썬 3.6.5의 주목할만한 변경 사항

파이썬 3.6.7의 주목할만한 변경 사항

파이썬 3.6.10의 주목할만한 변경 사항

파이썬 3.6.13의 주목할만한 변경 사항

Notable changes in Python 3.6.14

파이썬 3.5의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

PEP 492 - async와 await 구문을 사용하는 코루틴

PEP 465 - 행렬 곱셈을 위한 전용 중위(infix) 연산자

PEP 448 - 추가적인 언 패킹 일반화

PEP 461 - bytes와 bytearray를 위한 퍼센트 포매팅 지원

PEP 484 - 형 힌트

PEP 471 - os.scandir() 함수 – 더 빠르고 더 나은 디렉터리 이터레이터

PEP 475: EINTR로 실패한 시스템 호출 재시도

PEP 479: 제너레이터 내부에서의 StopIteration 처리 변경

PEP 485: 대략적인 동등성을 테스트하는 함수

PEP 486: 파이썬 런처가 가상 환경을 인식하도록 만들기

PEP 488: PYO 파일 제거

PEP 489: 다단계 확장 모듈 초기화

기타 언어 변경

새로운 모듈

typing

zipapp

개선된 모듈

argparse

asyncio

bz2

cgi

cmath

code

collections

collections.abc

compileall

concurrent.futures

configparser

contextlib

csv

curses

dbm

difflib

distutils

doctest

email

enum

faulthandler

functools

glob

gzip

heapq

http

http.client

idlelib 및 IDLE

imaplib

imghdr

importlib

inspect

io

ipaddress

json

linecache

locale

logging

lzma

math

multiprocessing

operator

os

pathlib

pickle

poplib

re

readline

selectors

Shutil

signal

smtpd

smtplib

sndhdr

socket

ssl

메모리 BIO 지원

응용 프로그램 계층 프로토콜 협상 지원

기타 변경 사항

sqlite3

subprocess

sys

sysconfig

tarfile

threading

time

timeit

tkinter

traceback

types

unicodedata

unittest

unittest.mock

urllib

wsgiref

xmlrpc

xml.sax

zipfile

기타 모듈 수준 변경

최적화

빌드와 C API 변경

폐지

새 키워드

폐지된 파이썬 동작

지원되지 않는 운영 체제

폐지된 파이썬 모듈, 함수 및 메서드

제거

API 및 기능 제거

파이썬 3.5로 이식하기

파이썬 동작의 변경

파이썬 API의 변경

C API의 변경

파이썬 3.5.4의 주목할만한 변경 사항

새로운 make regen-all 빌드 대상

make touch 빌드 대상 제거

What’s New In Python 3.4

Summary – Release Highlights

New Features

PEP 453: Explicit Bootstrapping of PIP in Python Installations

Bootstrapping pip By Default

Documentation Changes

PEP 446: Newly Created File Descriptors Are Non-Inheritable

Improvements to Codec Handling

PEP 451: A ModuleSpec Type for the Import System

Other Language Changes

New Modules

asyncio

ensurepip

enum

pathlib

selectors

statistics

tracemalloc

Improved Modules

abc

aifc

argparse

audioop

base64

collections

colorsys

contextlib

dbm

dis

doctest

email

filecmp

functools

gc

glob

hashlib

hmac

html

http

idlelib and IDLE

importlib

inspect

ipaddress

logging

marshal

mmap

multiprocessing

operator

os

pdb

pickle

plistlib

poplib

pprint

pty

pydoc

re

resource

select

shelve

shutil

smtpd

smtplib

socket

sqlite3

ssl

stat

struct

subprocess

sunau

sys

tarfile

textwrap

threading

traceback

types

urllib

unittest

venv

wave

weakref

xml.etree

zipfile

CPython Implementation Changes

PEP 445: Customization of CPython Memory Allocators

PEP 442: Safe Object Finalization

PEP 456: Secure and Interchangeable Hash Algorithm

PEP 436: Argument Clinic

Other Build and C API Changes

Other Improvements

Significant Optimizations

Deprecated

Deprecations in the Python API

Deprecated Features

Removed

Operating Systems No Longer Supported

API and Feature Removals

Code Cleanups

Porting to Python 3.4

Changes in ‘python’ Command Behavior

Changes in the Python API

Changes in the C API

Changed in 3.4.3

PEP 476: Enabling certificate verification by default for stdlib http clients

What’s New In Python 3.3

Summary – Release highlights

PEP 405: Virtual Environments

PEP 420: Implicit Namespace Packages

PEP 3118: New memoryview implementation and buffer protocol documentation

Features

API changes

PEP 393: Flexible String Representation

Functionality

Performance and resource usage

PEP 397: Python Launcher for Windows

PEP 3151: Reworking the OS and IO exception hierarchy

PEP 380: Syntax for Delegating to a Subgenerator

PEP 409: Suppressing exception context

PEP 414: Explicit Unicode literals

PEP 3155: Qualified name for classes and functions

PEP 412: Key-Sharing Dictionary

PEP 362: Function Signature Object

PEP 421: Adding sys.implementation

SimpleNamespace

Using importlib as the Implementation of Import

New APIs

Visible Changes

Other Language Changes

A Finer-Grained Import Lock

Builtin functions and types

New Modules

faulthandler

ipaddress

lzma

Improved Modules

abc

array

base64

binascii

bz2

codecs

collections

contextlib

crypt

curses

datetime

decimal

Features

API changes

email

Policy Framework

Provisional Policy with New Header API

Other API Changes

ftplib

functools

gc

hmac

http

html

imaplib

inspect

io

itertools

logging

math

mmap

multiprocessing

nntplib

os

pdb

pickle

pydoc

re

sched

select

shlex

shutil

signal

smtpd

smtplib

socket

socketserver

sqlite3

ssl

stat

struct

subprocess

sys

tarfile

tempfile

textwrap

threading

time

types

unittest

urllib

webbrowser

xml.etree.ElementTree

zlib

Optimizations

Build and C API Changes

Deprecated

Unsupported Operating Systems

Deprecated Python modules, functions and methods

Deprecated functions and types of the C API

Deprecated features

Porting to Python 3.3

Porting Python code

Porting C code

Building C extensions

Command Line Switch Changes

What’s New In Python 3.2

PEP 384: Defining a Stable ABI

PEP 389: Argparse Command Line Parsing Module

PEP 391: Dictionary Based Configuration for Logging

PEP 3148: The concurrent.futures module

PEP 3147: PYC Repository Directories

PEP 3149: ABI Version Tagged .so Files

PEP 3333: Python Web Server Gateway Interface v1.0.1

Other Language Changes

New, Improved, and Deprecated Modules

email

elementtree

functools

itertools

collections

threading

datetime and time

math

abc

io

reprlib

logging

csv

contextlib

decimal and fractions

ftp

popen

select

gzip and zipfile

tarfile

hashlib

ast

os

shutil

sqlite3

html

socket

ssl

nntp

certificates

imaplib

http.client

unittest

random

poplib

asyncore

tempfile

inspect

pydoc

dis

dbm

ctypes

site

sysconfig

pdb

configparser

urllib.parse

mailbox

turtledemo

Multi-threading

Optimizations

Unicode

Codecs

Documentation

IDLE

Code Repository

Build and C API Changes

Porting to Python 3.2

What’s New In Python 3.1

PEP 372: Ordered Dictionaries

PEP 378: Format Specifier for Thousands Separator

Other Language Changes

New, Improved, and Deprecated Modules

Optimizations

IDLE

Build and C API Changes

Porting to Python 3.1

What’s New In Python 3.0

Common Stumbling Blocks

Print Is A Function

Views And Iterators Instead Of Lists

Ordering Comparisons

Integers

Text Vs. Data Instead Of Unicode Vs. 8-bit

Overview Of Syntax Changes

New Syntax

Changed Syntax

Removed Syntax

Changes Already Present In Python 2.6

Library Changes

PEP 3101: A New Approach To String Formatting

Changes To Exceptions

Miscellaneous Other Changes

Operators And Special Methods

Builtins

Build and C API Changes

Performance

Porting To Python 3.0

What’s New in Python 2.7

The Future for Python 2.x

Changes to the Handling of Deprecation Warnings

Python 3.1 Features

PEP 372: Adding an Ordered Dictionary to collections

PEP 378: Format Specifier for Thousands Separator

PEP 389: The argparse Module for Parsing Command Lines

PEP 391: Dictionary-Based Configuration For Logging

PEP 3106: Dictionary Views

PEP 3137: The memoryview Object

Other Language Changes

Interpreter Changes

Optimizations

New and Improved Modules

New module: importlib

New module: sysconfig

ttk: Themed Widgets for Tk

Updated module: unittest

Updated module: ElementTree 1.3

Build and C API Changes

Capsules

Port-Specific Changes: Windows

Port-Specific Changes: Mac OS X

Port-Specific Changes: FreeBSD

Other Changes and Fixes

Porting to Python 2.7

New Features Added to Python 2.7 Maintenance Releases

Two new environment variables for debug mode

PEP 434: IDLE Enhancement Exception for All Branches

PEP 466: Network Security Enhancements for Python 2.7

PEP 477: Backport ensurepip (PEP 453) to Python 2.7

Bootstrapping pip By Default

Documentation Changes

PEP 476: Enabling certificate verification by default for stdlib http clients

PEP 493: HTTPS verification migration tools for Python 2.7

New make regen-all build target

Removal of make touch build target

Acknowledgements

What’s New in Python 2.6

Python 3.0

Changes to the Development Process

New Issue Tracker: Roundup

New Documentation Format: reStructuredText Using Sphinx

PEP 343: The ‘with’ statement

Writing Context Managers

The contextlib module

PEP 366: Explicit Relative Imports From a Main Module

PEP 370: Per-user site-packages Directory

PEP 371: The multiprocessing Package

PEP 3101: Advanced String Formatting

PEP 3105: print As a Function

PEP 3110: Exception-Handling Changes

PEP 3112: Byte Literals

PEP 3116: New I/O Library

PEP 3118: Revised Buffer Protocol

PEP 3119: Abstract Base Classes

PEP 3127: Integer Literal Support and Syntax

PEP 3129: Class Decorators

PEP 3141: A Type Hierarchy for Numbers

The fractions Module

Other Language Changes

Optimizations

Interpreter Changes

New and Improved Modules

The ast module

The future_builtins module

The json module: JavaScript Object Notation

The plistlib module: A Property-List Parser

ctypes Enhancements

Improved SSL Support

Deprecations and Removals

Build and C API Changes

Port-Specific Changes: Windows

Port-Specific Changes: Mac OS X

Port-Specific Changes: IRIX

Porting to Python 2.6

Acknowledgements

What’s New in Python 2.5

PEP 308: Conditional Expressions

PEP 309: Partial Function Application

PEP 314: Metadata for Python Software Packages v1.1

PEP 328: Absolute and Relative Imports

PEP 338: Executing Modules as Scripts

PEP 341: Unified try/except/finally

PEP 342: New Generator Features

PEP 343: The ‘with’ statement

Writing Context Managers

The contextlib module

PEP 352: Exceptions as New-Style Classes

PEP 353: Using ssize_t as the index type

PEP 357: The ‘__index__’ method

Other Language Changes

Interactive Interpreter Changes

Optimizations

New, Improved, and Removed Modules

The ctypes package

The ElementTree package

The hashlib package

The sqlite3 package

The wsgiref package

Build and C API Changes

Port-Specific Changes

Porting to Python 2.5

Acknowledgements

What’s New in Python 2.4

PEP 218: Built-In Set Objects

PEP 237: Unifying Long Integers and Integers

PEP 289: Generator Expressions

PEP 292: Simpler String Substitutions

PEP 318: Decorators for Functions and Methods

PEP 322: Reverse Iteration

PEP 324: New subprocess Module

PEP 327: Decimal Data Type

Why is Decimal needed?

The Decimal type

The Context type

PEP 328: Multi-line Imports

PEP 331: Locale-Independent Float/String Conversions

Other Language Changes

Optimizations

New, Improved, and Deprecated Modules

cookielib

doctest

Build and C API Changes

Port-Specific Changes

Porting to Python 2.4

Acknowledgements

What’s New in Python 2.3

PEP 218: A Standard Set Datatype

PEP 255: Simple Generators

PEP 263: Source Code Encodings

PEP 273: Importing Modules from ZIP Archives

PEP 277: Unicode file name support for Windows NT

PEP 278: Universal Newline Support

PEP 279: enumerate()

PEP 282: The logging Package

PEP 285: A Boolean Type

PEP 293: Codec Error Handling Callbacks

PEP 301: Package Index and Metadata for Distutils

PEP 302: New Import Hooks

PEP 305: Comma-separated Files

PEP 307: Pickle Enhancements

Extended Slices

Other Language Changes

String Changes

Optimizations

New, Improved, and Deprecated Modules

Date/Time Type

The optparse Module

Pymalloc: A Specialized Object Allocator

Build and C API Changes

Port-Specific Changes

Other Changes and Fixes

Porting to Python 2.3

Acknowledgements

What’s New in Python 2.2

Introduction

PEPs 252 and 253: Type and Class Changes

Old and New Classes

Descriptors

Multiple Inheritance: The Diamond Rule

Attribute Access

Related Links

PEP 234: Iterators

PEP 255: Simple Generators

PEP 237: Unifying Long Integers and Integers

PEP 238: Changing the Division Operator

Unicode Changes

PEP 227: Nested Scopes

New and Improved Modules

Interpreter Changes and Fixes

Other Changes and Fixes

Acknowledgements

What’s New in Python 2.1

Introduction

PEP 227: Nested Scopes

PEP 236: __future__ Directives

PEP 207: Rich Comparisons

PEP 230: Warning Framework

PEP 229: New Build System

PEP 205: Weak References

PEP 232: Function Attributes

PEP 235: Importing Modules on Case-Insensitive Platforms

PEP 217: Interactive Display Hook

PEP 208: New Coercion Model

PEP 241: Metadata in Python Packages

New and Improved Modules

Other Changes and Fixes

Acknowledgements

What’s New in Python 2.0

Introduction

What About Python 1.6?

New Development Process

Unicode

List Comprehensions

Augmented Assignment

String Methods

Garbage Collection of Cycles

Other Core Changes

Minor Language Changes

Changes to Built-in Functions

Porting to 2.0

Extending/Embedding Changes

Distutils: Making Modules Easy to Install

XML Modules

SAX2 Support

DOM Support

Relationship to PyXML

Module changes

New modules

IDLE Improvements

Deleted and Deprecated Modules

Acknowledgements

Changelog

Python next

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파이썬 자습서

1. 입맛 돋우기

2. 파이썬 인터프리터 사용하기

2.1. 인터프리터 실행하기

2.1.1. 인자 전달

2.1.2. 대화형 모드

2.2. 인터프리터와 환경

2.2.1. 소스 코드 인코딩

3. 파이썬의 간략한 소개

3.1. 파이썬을 계산기로 사용하기

3.1.1. 숫자

3.1.2. Text

3.1.3. 리스트

3.2. 프로그래밍으로의 첫걸음

4. 기타 제어 흐름 도구

4.1. if 문

4.2. for 문

4.3. range() 함수

4.4. break and continue Statements

4.5. else Clauses on Loops

4.6. pass 문

4.7. match Statements

4.8. 함수 정의하기

4.9. 함수 정의 더 보기

4.9.1. 기본 인자 값

4.9.2. 키워드 인자

4.9.3. 특수 매개 변수

4.9.3.1. 위치-키워드(Positional-or-Keyword) 인자

4.9.3.2. 위치 전용 매개 변수

4.9.3.3. 키워드 전용 인자

4.9.3.4. 함수 예제

4.9.3.5. 복습

4.9.4. 임의의 인자 목록

4.9.5. 인자 목록 언 패킹

4.9.6. 람다 표현식

4.9.7. 도큐멘테이션 문자열

4.9.8. 함수 어노테이션

4.10. 막간극: 코딩 스타일

5. 자료 구조

5.1. 리스트 더 보기

5.1.1. 리스트를 스택으로 사용하기

5.1.2. 리스트를 큐로 사용하기

5.1.3. 리스트 컴프리헨션

5.1.4. 중첩된 리스트 컴프리헨션

5.2. del 문

5.3. 튜플과 시퀀스

5.4. 집합

5.5. 딕셔너리

5.6. 루프 테크닉

5.7. 조건 더 보기

5.8. 시퀀스와 다른 형들을 비교하기

6. 모듈

6.1. 모듈 더 보기

6.1.1. 모듈을 스크립트로 실행하기

6.1.2. 모듈 검색 경로

6.1.3. “컴파일된” 파이썬 파일

6.2. 표준 모듈들

6.3. dir() 함수

6.4. 패키지

6.4.1. 패키지에서 * 임포트 하기

6.4.2. 패키지 내부 간의 참조

6.4.3. 여러 디렉터리에 있는 패키지

7. 입력과 출력

7.1. 장식적인 출력 포매팅

7.1.1. 포맷 문자열 리터럴

7.1.2. 문자열 format() 메서드

7.1.3. 수동 문자열 포매팅

7.1.4. 예전의 문자열 포매팅

7.2. 파일을 읽고 쓰기

7.2.1. 파일 객체의 매소드

7.2.2. json 으로 구조적인 데이터를 저장하기

8. 에러와 예외

8.1. 문법 에러

8.2. 예외

8.3. 예외 처리하기

8.4. 예외 일으키기

8.5. 예외 연쇄

8.6. 사용자 정의 예외

8.7. 뒷정리 동작 정의하기

8.8. 미리 정의된 뒷정리 동작들

8.9. Raising and Handling Multiple Unrelated Exceptions

8.10. Enriching Exceptions with Notes

9. 클래스

9.1. 이름과 객체에 관한 한마디

9.2. 파이썬 스코프와 이름 공간

9.2.1. 스코프와 이름 공간 예

9.3. 클래스와의 첫 만남

9.3.1. 클래스 정의 문법

9.3.2. 클래스 객체

9.3.3. 인스턴스 객체

9.3.4. 메서드 객체

9.3.5. 클래스와 인스턴스 변수

9.4. 기타 주의사항들

9.5. 상속

9.5.1. 다중 상속

9.6. 비공개 변수

9.7. 잡동사니

9.8. 이터레이터

9.9. 제너레이터

9.10. 제너레이터 표현식

10. 표준 라이브러리 둘러보기

10.1. 운영 체제 인터페이스

10.2. 파일 와일드카드

10.3. 명령행 인자

10.4. 에러 출력 리디렉션과 프로그램 종료

10.5. 문자열 패턴 매칭

10.6. 수학

10.7. 인터넷 액세스

10.8. 날짜와 시간

10.9. 데이터 압축

10.10. 성능 측정

10.11. 품질 관리

10.12. 배터리가 포함됩니다

11. 표준 라이브러리 둘러보기 — 2부

11.1. 출력 포매팅

11.2. 템플릿

11.3. 바이너리 데이터 레코드 배치 작업

11.4. 다중 스레딩

11.5. 로깅

11.6. 약한 참조

11.7. 리스트 작업 도구

11.8. Decimal Floating-Point Arithmetic

12. 가상 환경 및 패키지

12.1. 소개

12.2. 가상 환경 만들기

12.3. pip로 패키지 관리하기

13. 이제 뭘 하지?

14. 대화형 입력 편집 및 히스토리 치환

14.1. 탭 완성 및 히스토리 편집

14.2. 대화형 인터프리터 대안

15. Floating-Point Arithmetic: Issues and Limitations

15.1. 표현 오류

16. 부록

16.1. 대화형 모드

16.1.1. 에러 처리

16.1.2. 실행 가능한 파이썬 스크립트

16.1.3. 대화형 시작 파일

16.1.4. 커스터마이제이션 모듈

파이썬 설정 및 사용법

1. 명령 줄과 환경

1.1. 명령 줄

1.1.1. 인터페이스 옵션

1.1.2. 일반 옵션

1.1.3. 기타 옵션

1.1.4. Controlling color

1.1.5. 사용해서는 안 되는 옵션

1.2. 환경 변수

1.2.1. 디버그 모드 변수

2. 유닉스 플랫폼에서 파이썬 사용하기

2.1. 최신 버전의 파이썬 내려받기와 설치

2.1.1. 리눅스

2.1.2. FreeBSD와 OpenBSD

2.2. 파이썬 빌드하기

2.3. 파이썬 관련 경로와 파일

2.4. 잡동사니

2.5. Custom OpenSSL

3. Configure Python

3.1. Build Requirements

3.2. Generated files

3.2.1. configure script

3.3. Configure Options

3.3.1. General Options

3.3.2. C compiler options

3.3.3. Linker options

3.3.4. Options for third-party dependencies

3.3.5. WebAssembly Options

3.3.6. Install Options

3.3.7. Performance options

3.3.8. Python Debug Build

3.3.9. Debug options

3.3.10. Linker options

3.3.11. Libraries options

3.3.12. Security Options

3.3.13. macOS Options

3.3.14. iOS Options

3.3.15. Cross Compiling Options

3.4. Python Build System

3.4.1. Main files of the build system

3.4.2. Main build steps

3.4.3. Main Makefile targets

3.4.3.1. make

3.4.3.2. make platform

3.4.3.3. make profile-opt

3.4.3.4. make clean

3.4.3.5. make distclean

3.4.3.6. make install

3.4.3.7. make test

3.4.3.8. make ci

3.4.3.9. make buildbottest

3.4.3.10. make regen-all

3.4.4. C extensions

3.5. Compiler and linker flags

3.5.1. Preprocessor flags

3.5.2. Compiler flags

3.5.3. Linker flags

4. 윈도우에서 파이썬 사용하기

4.1. 전체 설치 프로그램

4.1.1. 설치 단계

4.1.2. MAX_PATH 제한 제거하기

4.1.3. UI 없이 설치하기

4.1.4. 다운로드 없이 설치하기

4.1.5. 설치 수정하기

4.1.6. Installing Free-threaded Binaries

4.2. Microsoft Store 패키지

4.2.1. Known issues

4.2.1.1. Redirection of local data, registry, and temporary paths

4.3. nuget.org 패키지

4.3.1. Free-threaded packages

4.4. 내장 가능한 패키지

4.4.1. 파이썬 응용 프로그램

4.4.2. 파이썬 내장하기

4.5. 대체 번들

4.6. 파이썬 구성하기

4.6.1. 보충 설명: 환경 변수 설정하기

4.6.2. 파이썬 실행 파일 찾기

4.7. UTF-8 모드

4.8. 윈도우 용 파이썬 런처

4.8.1. 시작하기

4.8.1.1. 명령 줄에서

4.8.1.2. 가상 환경

4.8.1.3. 스크립트에서

4.8.1.4. 파일 연결에서

4.8.2. 셔뱅 줄

4.8.3. 셔뱅 줄의 인자

4.8.4. 사용자 정의

4.8.4.1. INI 파일을 통한 사용자 정의

4.8.4.2. 기본 파이썬 버전 사용자 정의

4.8.5. 진단

4.8.6. Dry Run

4.8.7. Install on demand

4.8.8. Return codes

4.9. 모듈 찾기

4.10. 추가 모듈

4.10.1. PyWin32

4.10.2. cx_Freeze

4.11. 윈도우에서 파이썬 컴파일하기

4.12. 기타 플랫폼

5. Using Python on macOS

5.1. Using Python for macOS from python.org

5.1.1. Installation steps

5.1.2. 파이썬 스크립트를 실행하는 방법

5.2. Alternative Distributions

5.3. 추가 파이썬 패키지 설치하기

5.4. GUI Programming

5.5. Advanced Topics

5.5.1. Installing Free-threaded Binaries

5.5.2. Installing using the command line

5.5.3. Distributing Python Applications

5.5.4. App Store Compliance

5.6. 기타 자원

6. Using Python on Android

6.1. Adding Python to an Android app

7. Using Python on iOS

7.1. Python at runtime on iOS

7.1.1. iOS version compatibility

7.1.2. Platform identification

7.1.3. Standard library availability

7.1.4. Binary extension modules

7.1.5. Compiler stub binaries

7.2. Installing Python on iOS

7.2.1. Tools for building iOS apps

7.2.2. Adding Python to an iOS project

7.3. App Store Compliance

8. 편집기와 IDE

파이썬 언어 레퍼런스

1. 개요

1.1. 대안 구현들

1.2. 표기법

2. 어휘 분석

2.1. 줄 구조(Line structure)

2.1.1. 논리적인 줄

2.1.2. 물리적인 줄

2.1.3. 주석

2.1.4. 인코딩 선언

2.1.5. 명시적인 줄 결합

2.1.6. 묵시적인 줄 결합

2.1.7. 빈 줄

2.1.8. 들여쓰기

2.1.9. 토큰 사이의 공백

2.2. 다른 토큰들

2.3. 식별자와 키워드

2.3.1. 키워드

2.3.2. Soft Keywords

2.3.3. 식별자의 예약 영역

2.4. 리터럴

2.4.1. 문자열과 바이트열 리터럴

2.4.1.1. Escape sequences

2.4.2. 문자열 리터럴 이어붙이기

2.4.3. f-strings

2.4.4. 숫자 리터럴

2.4.5. 정수 리터럴

2.4.6. Floating-point literals

2.4.7. 허수 리터럴

2.5. 연산자

2.6. 구분자

3. 데이터 모델

3.1. 객체, 값, 형

3.2. 표준형 계층

3.2.1. None

3.2.2. NotImplemented

3.2.3. Ellipsis

3.2.4. numbers.Number

3.2.4.1. numbers.Integral

3.2.4.2. numbers.Real (float)

3.2.4.3. numbers.Complex (complex)

3.2.5. 시퀀스들

3.2.5.1. 불변 시퀀스

3.2.5.2. 가변 시퀀스

3.2.6. 집합 형들(Set types)

3.2.7. 매핑(Mappings)

3.2.7.1. 딕셔너리(Dictionaries)

3.2.8. 콜러블(Callable types)

3.2.8.1. 사용자 정의 함수

3.2.8.1.1. Special read-only attributes

__globals__

__closure__

3.2.8.1.2. Special writable attributes

__doc__

__name__

__qualname__

__module__

__defaults__

__code__

__dict__

__annotations__

__annotate__

__kwdefaults__

__type_params__

3.2.8.2. 인스턴스 메서드(Instance methods)

__self__

__func__

__doc__

__name__

__module__

3.2.8.3. 제너레이터 함수(Generator functions)

3.2.8.4. 코루틴 함수(Coroutine functions)

3.2.8.5. 비동기 제너레이터 함수(Asynchronous generator functions)

3.2.8.6. 내장 함수(Built-in functions)

3.2.8.7. 내장 메서드(Built-in methods)

3.2.8.8. 클래스(Classes)

3.2.8.9. 클래스 인스턴스(Class Instances)

3.2.9. 모듈(Modules)

3.2.9.1. Import-related attributes on module objects

__name__

__spec__

__package__

__loader__

__path__

__file__

__cached__

3.2.9.2. Other writable attributes on module objects

__doc__

__annotations__

__annotate__

3.2.9.3. Module dictionaries

__dict__

3.2.10. 사용자 정의 클래스(Custom classes)

3.2.10.1. Special attributes

__name__

__qualname__

__module__

__dict__

__bases__

__doc__

__annotations__

__annotate__()

__type_params__

__static_attributes__

__firstlineno__

__mro__

3.2.10.2. Special methods

mro()

__subclasses__()

3.2.11. 클래스 인스턴스(Class instances)

3.2.11.1. Special attributes

__class__

__dict__

3.2.12. I/O 객체 (파일 객체라고도 알려져 있습니다)

3.2.13. 내부 형(Internal types)

3.2.13.1. 코드 객체(Code objects)

3.2.13.1.1. Special read-only attributes

co_name

co_qualname

co_argcount

co_posonlyargcount

co_kwonlyargcount

co_nlocals

co_varnames

co_cellvars

co_freevars

co_code

co_consts

co_names

co_filename

co_firstlineno

co_lnotab

co_stacksize

co_flags

3.2.13.1.2. Methods on code objects

co_positions()

co_lines()

replace()

3.2.13.2. 프레임 객체(Frame objects)

3.2.13.2.1. Special read-only attributes

f_back

f_code

f_locals

f_globals

f_builtins

f_lasti

3.2.13.2.2. Special writable attributes

f_trace

f_trace_lines

f_trace_opcodes

f_lineno

3.2.13.2.3. Frame object methods

clear()

3.2.13.3. 트레이스백 객체(Traceback objects)

tb_frame

tb_lineno

tb_lasti

tb_next

3.2.13.4. 슬라이스 객체(Slice objects)

indices()

3.2.13.5. 스태틱 메서드 객체(Static method objects)

3.2.13.6. 클래스 메서드 객체(Class method objects)

3.3. 특수 메서드 이름들

3.3.1. 기본적인 커스터마이제이션

__new__()

__init__()

__del__()

__repr__()

__str__()

__bytes__()

__format__()

__lt__()

__le__()

__eq__()

__ne__()

__gt__()

__ge__()

__hash__()

__bool__()

3.3.2. 어트리뷰트 액세스 커스터마이제이션

__getattr__()

__getattribute__()

__setattr__()

__delattr__()

__dir__()

3.3.2.1. 모듈 어트리뷰트 액세스 커스터마이제이션

3.3.2.2. 디스크립터 구현하기

__get__()

__set__()

__delete__()

__objclass__

3.3.2.3. 디스크립터 호출하기

3.3.2.4. __slots__

__slots__

3.3.3. 클래스 생성 커스터마이제이션

__init_subclass__()

__set_name__()

3.3.3.1. 메타 클래스

3.3.3.2. MRO 항목 결정하기

__mro_entries__()

3.3.3.3. 적절한 메타 클래스 선택하기

3.3.3.4. 클래스 이름 공간 준비하기

3.3.3.5. 클래스 바디 실행하기

3.3.3.6. 클래스 객체 만들기

3.3.3.7. 메타 클래스의 용도

3.3.4. 인스턴스 및 서브 클래스 검사 커스터마이제이션

__instancecheck__()

__subclasscheck__()

3.3.5. 제네릭 형 흉내 내기

__class_getitem__()

3.3.5.1. The purpose of __class_getitem__

3.3.5.2. __class_getitem__ versus __getitem__

3.3.6. 콜러블 객체 흉내 내기

__call__()

3.3.7. 컨테이너형 흉내 내기

__len__()

__length_hint__()

__getitem__()

__setitem__()

__delitem__()

__missing__()

__iter__()

__reversed__()

__contains__()

3.3.8. 숫자 형 흉내 내기

__add__()

__sub__()

__mul__()

__matmul__()

__truediv__()

__floordiv__()

__mod__()

__divmod__()

__pow__()

__lshift__()

__rshift__()

__and__()

__xor__()

__or__()

__radd__()

__rsub__()

__rmul__()

__rmatmul__()

__rtruediv__()

__rfloordiv__()

__rmod__()

__rdivmod__()

__rpow__()

__rlshift__()

__rrshift__()

__rand__()

__rxor__()

__ror__()

__iadd__()

__isub__()

__imul__()

__imatmul__()

__itruediv__()

__ifloordiv__()

__imod__()

__ipow__()

__ilshift__()

__irshift__()

__iand__()

__ixor__()

__ior__()

__neg__()

__pos__()

__abs__()

__invert__()

__complex__()

__int__()

__float__()

__index__()

__round__()

__trunc__()

__floor__()

__ceil__()

3.3.9. with 문 컨텍스트 관리자

__enter__()

__exit__()

3.3.10. Customizing positional arguments in class pattern matching

__match_args__

3.3.11. Emulating buffer types

__buffer__()

__release_buffer__()

3.3.12. Annotations

__annotations__

__annotate__()

3.3.13. 특수 메서드 조회

3.4. 코루틴(Coroutines)

3.4.1. 어웨이터블 객체(Awaitable Objects)

__await__()

3.4.2. 코루틴 객체(Coroutine Objects)

send()

throw()

close()

3.4.3. 비동기 이터레이터(Asynchronous Iterators)

__aiter__()

__anext__()

3.4.4. 비동기 컨텍스트 관리자

__aenter__()

__aexit__()

4. 실행 모델

4.1. 프로그램의 구조

4.2. 이름과 연결(binding)

4.2.1. 이름의 연결

4.2.2. 이름의 검색(resolution)

4.2.3. Annotation scopes

4.2.4. Lazy evaluation

4.2.5. builtins 와 제한된 실행

4.2.6. 동적 기능과의 상호작용

4.3. 예외

5. 임포트 시스템

5.1. importlib

5.2. 패키지(package)

5.2.1. 정규 패키지

5.2.2. 이름 공간 패키지

5.3. 검색

5.3.1. 모듈 캐시

5.3.2. 파인더(finder)와 로더(loader)

5.3.3. 임포트 훅(import hooks)

5.3.4. 메타 경로(meta path)

5.4. 로딩(loading)

5.4.1. 로더

5.4.2. 서브 모듈

5.4.3. Module specs

5.4.4. __path__ attributes on modules

5.4.5. 모듈 repr

5.4.6. 캐시된 바이트 코드 무효화

5.5. 경로 기반 파인더

5.5.1. 경로 엔트리 파인더

5.5.2. 경로 엔트리 파인더 프로토콜

5.6. 표준 임포트 시스템 교체하기

5.7. 패키지 상대 임포트

5.8. __main__ 에 대한 특별한 고려

5.8.1. __main__.__spec__

5.9. 참고문헌

6. 표현식

6.1. 산술 변환

6.2. 아톰 (Atoms)

6.2.1. 식별자 (이름)

6.2.1.1. Private name mangling

6.2.2. 리터럴 (Literals)

6.2.3. 괄호 안에 넣은 형

6.2.4. 리스트, 집합, 딕셔너리의 디스플레이(display)

6.2.5. 리스트 디스플레이

6.2.6. 집합 디스플레이

6.2.7. 딕셔너리 디스플레이

6.2.8. 제너레이터 표현식 (Generator expressions)

6.2.9. 일드 표현식(Yield expressions)

6.2.9.1. 제너레이터-이터레이터 메서드

__next__()

send()

throw()

close()

6.2.9.2. 사용 예

6.2.9.3. 비동기 제너레이터 함수

6.2.9.4. 비동기 제너레이터-이터레이터 메서드

__anext__()

asend()

athrow()

aclose()

6.3. 프라이머리

6.3.1. 어트리뷰트 참조

6.3.2. 서브스크립션(Subscriptions)

6.3.3. 슬라이싱(Slicings)

6.3.4. 호출

6.4. 어웨이트 표현식

6.5. 거듭제곱 연산자

6.6. 일 항 산술과 비트 연산

6.7. 이항 산술 연산

6.8. 시프트 연산

6.9. 이항 비트 연산

6.10. 비교

6.10.1. 값 비교

6.10.2. 멤버십 검사 연산

6.10.3. 아이덴티티 비교

6.11. 논리 연산(Boolean operations)

6.12. 대입 표현식

6.13. 조건 표현식(Conditional expressions)

6.14. 람다(Lambdas)

6.15. 표현식 목록(Expression lists)

6.16. 값을 구하는 순서

6.17. 연산자 우선순위

7. 단순문(Simple statements)

7.1. 표현식 문

7.2. 대입문

7.2.1. 증분 대입문(Augmented assignment statements)

7.2.2. 어노테이트된 대입문(Annotated assignment statements)

7.3. assert 문

7.4. pass 문

7.5. del 문

7.6. return 문

7.7. yield 문

7.8. raise 문

7.9. break 문

7.10. continue 문

7.11. 임포트(import) 문

7.11.1. 퓨처 문

7.12. global 문

7.13. nonlocal 문

7.14. The type statement

8. 복합문(Compound statements)

8.1. if 문

8.2. while 문

8.3. for 문

8.4. try 문

8.4.1. except clause

8.4.2. except* clause

8.4.3. else clause

8.4.4. finally clause

8.5. with 문

8.6. The match statement

8.6.1. Overview

8.6.2. Guards

8.6.3. Irrefutable Case Blocks

8.6.4. Patterns

8.6.4.1. OR Patterns

8.6.4.2. AS Patterns

8.6.4.3. Literal Patterns

8.6.4.4. Capture Patterns

8.6.4.5. Wildcard Patterns

8.6.4.6. Value Patterns

8.6.4.7. Group Patterns

8.6.4.8. Sequence Patterns

8.6.4.9. Mapping Patterns

8.6.4.10. Class Patterns

8.7. 함수 정의

8.8. 클래스 정의

8.9. 코루틴

8.9.1. 코루틴 함수 정의

8.9.2. async for 문

8.9.3. async with 문

8.10. Type parameter lists

8.10.1. Generic functions

8.10.2. Generic classes

8.10.3. Generic type aliases

8.11. Annotations

9. 최상위 요소들

9.1. 완전한 파이썬 프로그램

9.2. 파일 입력

9.3. 대화형 입력

9.4. 표현식 입력

10. 전체 문법 규격

파이썬 표준 라이브러리

소개

가용성에 대한 참고 사항

WebAssembly platforms

Mobile platforms

내장 함수

abs()

aiter()

all()

anext()

any()

ascii()

bin()

bool

breakpoint()

callable()

chr()

classmethod()

compile()

complex

delattr()

dir()

divmod()

enumerate()

eval()

exec()

filter()

float

format()

getattr()

globals()

hasattr()

hash()

help()

hex()

id()

input()

int

isinstance()

issubclass()

iter()

len()

locals()

map()

max()

min()

next()

object

oct()

open()

ord()

pow()

print()

property

getter()

setter()

deleter()

__name__

repr()

reversed()

round()

setattr()

slice

start

stop

step

sorted()

staticmethod()

sum()

super

type

vars()

zip()

__import__()

내장 상수

False

True

None

NotImplemented

Ellipsis

__debug__

site 모듈에 의해 추가된 상수들

quit

exit

copyright

credits

license

내장형

논리값 검사

논리 연산 — and, or, not

비교

숫자 형 — int, float, complex

정수 형에 대한 비트 연산

정수 형에 대한 추가 메서드

bit_length()

bit_count()

to_bytes()

from_bytes()

as_integer_ratio()

is_integer()

실수에 대한 추가 메서드

from_number()

as_integer_ratio()

is_integer()

hex()

fromhex()

Additional Methods on Complex

from_number()

숫자 형의 해싱

Boolean Type - bool

이터레이터 형

__iter__()

__iter__()

__next__()

제너레이터 형

시퀀스 형 — list, tuple, range

공통 시퀀스 연산

불변 시퀀스 형

가변 시퀀스 형

리스트

list

sort()

튜플

tuple

범위

range

start

stop

step

텍스트 시퀀스 형 — str

str

문자열 메서드

capitalize()

casefold()

center()

count()

encode()

endswith()

expandtabs()

find()

format()

format_map()

index()

isalnum()

isalpha()

isascii()

isdecimal()

isdigit()

isidentifier()

islower()

isnumeric()

isprintable()

isspace()

istitle()

isupper()

join()

ljust()

lower()

lstrip()

maketrans()

partition()

removeprefix()

removesuffix()

replace()

rfind()

rindex()

rjust()

rpartition()

rsplit()

rstrip()

split()

splitlines()

startswith()

strip()

swapcase()

title()

translate()

upper()

zfill()

printf 스타일 문자열 포매팅

바이너리 시퀀스 형 — bytes, bytearray, memoryview

바이트열 객체

bytes

fromhex()

hex()

바이트 배열 객체

bytearray

fromhex()

hex()

바이트열 과 바이트 배열 연산

count()

count()

removeprefix()

removeprefix()

removesuffix()

removesuffix()

decode()

decode()

endswith()

endswith()

find()

find()

index()

index()

join()

join()

maketrans()

maketrans()

partition()

partition()

replace()

replace()

rfind()

rfind()

rindex()

rindex()

rpartition()

rpartition()

startswith()

startswith()

translate()

translate()

center()

center()

ljust()

ljust()

lstrip()

lstrip()

rjust()

rjust()

rsplit()

rsplit()

rstrip()

rstrip()

split()

split()

strip()

strip()

capitalize()

capitalize()

expandtabs()

expandtabs()

isalnum()

isalnum()

isalpha()

isalpha()

isascii()

isascii()

isdigit()

isdigit()

islower()

islower()

isspace()

isspace()

istitle()

istitle()

isupper()

isupper()

lower()

lower()

splitlines()

splitlines()

swapcase()

swapcase()

title()

title()

upper()

upper()

zfill()

zfill()

printf 스타일 바이너리 포매팅

메모리 뷰

memoryview

__eq__()

tobytes()

hex()

tolist()

toreadonly()

release()

cast()

obj

nbytes

readonly

format

itemsize

ndim

shape

strides

suboffsets

c_contiguous

f_contiguous

contiguous

집합 형 — set, frozenset

set

frozenset

isdisjoint()

issubset()

issuperset()

union()

intersection()

difference()

symmetric_difference()

copy()

update()

intersection_update()

difference_update()

symmetric_difference_update()

add()

remove()

discard()

pop()

clear()

매핑 형 — dict

dict

clear()

copy()

fromkeys()

get()

items()

keys()

pop()

popitem()

setdefault()

update()

values()

딕셔너리 뷰 객체

컨텍스트 관리자 형

__enter__()

__exit__()

Type Annotation Types — Generic Alias, Union

제네릭 에일리어스 형

Standard Generic Classes

Special Attributes of GenericAlias objects

__origin__

__args__

__parameters__

__unpacked__

Union Type

기타 내장형

모듈

클래스와 클래스 인스턴스

함수

메서드

코드 객체

형 객체

널 객체

Ellipsis 객체

NotImplemented 객체

내부 객체

특수 어트리뷰트

__name__

__qualname__

__module__

__doc__

__type_params__

Integer string conversion length limitation

Affected APIs

Configuring the limit

Recommended configuration

내장 예외

Exception context

__context__

__cause__

__suppress_context__

Inheriting from built-in exceptions

베이스 클래스

BaseException

args

with_traceback()

__traceback__

add_note()

__notes__

Exception

ArithmeticError

BufferError

LookupError

구체적인 예외

AssertionError

AttributeError

EOFError

FloatingPointError

GeneratorExit

ImportError

name

path

ModuleNotFoundError

IndexError

KeyError

KeyboardInterrupt

MemoryError

NameError

NotImplementedError

OSError

errno

winerror

strerror

filename

filename2

OverflowError

PythonFinalizationError

RecursionError

ReferenceError

RuntimeError

StopIteration

value

StopAsyncIteration

SyntaxError

filename

lineno

offset

text

end_lineno

end_offset

IndentationError

TabError

SystemError

SystemExit

code

TypeError

UnboundLocalError

UnicodeError

encoding

reason

object

start

end

UnicodeEncodeError

UnicodeDecodeError

UnicodeTranslateError

ValueError

ZeroDivisionError

EnvironmentError

IOError

WindowsError

OS 예외

BlockingIOError

characters_written

ChildProcessError

ConnectionError

BrokenPipeError

ConnectionAbortedError

ConnectionRefusedError

ConnectionResetError

FileExistsError

FileNotFoundError

InterruptedError

IsADirectoryError

NotADirectoryError

PermissionError

ProcessLookupError

TimeoutError

경고

Warning

UserWarning

DeprecationWarning

PendingDeprecationWarning

SyntaxWarning

RuntimeWarning

FutureWarning

ImportWarning

UnicodeWarning

EncodingWarning

BytesWarning

ResourceWarning

Exception groups

ExceptionGroup

BaseExceptionGroup

message

exceptions

subgroup()

split()

derive()

예외 계층 구조

텍스트 처리 서비스

string — Common string operations

문자열 상수

ascii_letters

ascii_lowercase

ascii_uppercase

digits

hexdigits

octdigits

punctuation

printable

whitespace

사용자 지정 문자열 포매팅

Formatter

format()

vformat()

parse()

get_field()

get_value()

check_unused_args()

format_field()

convert_field()

포맷 문자열 문법

포맷 명세 미니 언어

포맷 예제

템플릿 문자열

Template

substitute()

safe_substitute()

is_valid()

get_identifiers()

template

도움 함수

capwords()

re — Regular expression operations

정규식 문법

모듈 내용

Flags

RegexFlag

A

ASCII

DEBUG

I

IGNORECASE

L

LOCALE

M

MULTILINE

NOFLAG

S

DOTALL

U

UNICODE

X

VERBOSE

Functions

compile()

search()

match()

fullmatch()

split()

findall()

finditer()

sub()

subn()

escape()

purge()

Exceptions

PatternError

msg

pattern

pos

lineno

colno

정규식 객체

Pattern

search()

match()

fullmatch()

split()

findall()

finditer()

sub()

subn()

flags

groups

groupindex

pattern

일치 객체

Match

expand()

group()

__getitem__()

groups()

groupdict()

start()

end()

span()

pos

endpos

lastindex

lastgroup

re

string

정규식 예제

쌍 검사하기

scanf() 시뮬레이션

search() 대 match()

전화번호부 만들기

텍스트 뒤섞기

모든 부사 찾기

모든 부사와 그 위치 찾기

날 문자열 표기법

토크나이저 작성하기

difflib — Helpers for computing deltas

Differ

HtmlDiff

__init__()

make_file()

make_table()

context_diff()

get_close_matches()

ndiff()

restore()

unified_diff()

diff_bytes()

IS_LINE_JUNK()

IS_CHARACTER_JUNK()

SequenceMatcher 객체

SequenceMatcher

set_seqs()

set_seq1()

set_seq2()

find_longest_match()

get_matching_blocks()

get_opcodes()

get_grouped_opcodes()

ratio()

quick_ratio()

real_quick_ratio()

SequenceMatcher 예제

Differ 객체

compare()

Differ 예제

difflib의 명령 줄 인터페이스

ndiff example

textwrap — Text wrapping and filling

wrap()

fill()

shorten()

dedent()

indent()

TextWrapper

width

expand_tabs

tabsize

replace_whitespace

drop_whitespace

initial_indent

subsequent_indent

fix_sentence_endings

break_long_words

break_on_hyphens

max_lines

placeholder

wrap()

fill()

unicodedata — Unicode Database

lookup()

name()

decimal()

digit()

numeric()

category()

bidirectional()

combining()

east_asian_width()

mirrored()

decomposition()

normalize()

is_normalized()

unidata_version

ucd_3_2_0

stringprep — Internet String Preparation

in_table_a1()

in_table_b1()

map_table_b2()

map_table_b3()

in_table_c11()

in_table_c12()

in_table_c11_c12()

in_table_c21()

in_table_c22()

in_table_c21_c22()

in_table_c3()

in_table_c4()

in_table_c5()

in_table_c6()

in_table_c7()

in_table_c8()

in_table_c9()

in_table_d1()

in_table_d2()

readline — GNU readline interface

backend

초기화 파일

parse_and_bind()

read_init_file()

줄 버퍼

get_line_buffer()

insert_text()

redisplay()

히스토리 파일

read_history_file()

write_history_file()

append_history_file()

get_history_length()

set_history_length()

히스토리 목록

clear_history()

get_current_history_length()

get_history_item()

remove_history_item()

replace_history_item()

add_history()

set_auto_history()

시동 훅

set_startup_hook()

set_pre_input_hook()

완성

set_completer()

get_completer()

get_completion_type()

get_begidx()

get_endidx()

set_completer_delims()

get_completer_delims()

set_completion_display_matches_hook()

예제

rlcompleter — Completion function for GNU readline

Completer

complete()

바이너리 데이터 서비스

struct — Interpret bytes as packed binary data

함수와 예외

error

pack()

pack_into()

unpack()

unpack_from()

iter_unpack()

calcsize()

포맷 문자열

바이트 순서, 크기 및 정렬

포맷 문자

예

Applications

Native Formats

Standard Formats

클래스

Struct

pack()

pack_into()

unpack()

unpack_from()

iter_unpack()

format

size

codecs — Codec registry and base classes

encode()

decode()

lookup()

CodecInfo

name

encode

decode

incrementalencoder

incrementaldecoder

streamwriter

streamreader

getencoder()

getdecoder()

getincrementalencoder()

getincrementaldecoder()

getreader()

getwriter()

register()

unregister()

open()

EncodedFile()

iterencode()

iterdecode()

BOM

BOM_BE

BOM_LE

BOM_UTF8

BOM_UTF16

BOM_UTF16_BE

BOM_UTF16_LE

BOM_UTF32

BOM_UTF32_BE

BOM_UTF32_LE

코덱 베이스 클래스

에러 처리기

register_error()

lookup_error()

strict_errors()

ignore_errors()

replace_errors()

backslashreplace_errors()

xmlcharrefreplace_errors()

namereplace_errors()

상태 없는 인코딩과 디코딩

Codec

encode()

decode()

증분 인코딩과 디코딩

IncrementalEncoder 객체

IncrementalEncoder

encode()

reset()

getstate()

setstate()

IncrementalDecoder 객체

IncrementalDecoder

decode()

reset()

getstate()

setstate()

스트림 인코딩과 디코딩

StreamWriter 객체

StreamWriter

write()

writelines()

reset()

StreamReader 객체

StreamReader

read()

readline()

readlines()

reset()

StreamReaderWriter 객체

StreamReaderWriter

StreamRecoder 객체

StreamRecoder

인코딩과 유니코드

표준 인코딩

파이썬 특정 인코딩

텍스트 인코딩

바이너리 변환

텍스트 변환

encodings.idna — 응용 프로그램에서의 국제화된 도메인 이름

nameprep()

ToASCII()

ToUnicode()

encodings.mbcs — 윈도우 ANSI 코드 페이지

encodings.utf_8_sig — BOM 서명이 있는 UTF-8 코덱

데이터형

datetime — Basic date and time types

어웨어와 나이브 객체

상수

MINYEAR

MAXYEAR

UTC

사용 가능한 형

공통 속성

객체가 어웨어한지 나이브한지 판단하기

timedelta 객체

timedelta

min

max

resolution

days

seconds

microseconds

total_seconds()

사용 예: timedelta

date 객체

date

today()

fromtimestamp()

fromordinal()

fromisoformat()

fromisocalendar()

strptime()

min

max

resolution

year

month

day

replace()

timetuple()

toordinal()

weekday()

isoweekday()

isocalendar()

isoformat()

__str__()

ctime()

strftime()

__format__()

사용 예: date

datetime 객체

datetime

today()

now()

utcnow()

fromtimestamp()

utcfromtimestamp()

fromordinal()

combine()

fromisoformat()

fromisocalendar()

strptime()

min

max

resolution

year

month

day

hour

minute

second

microsecond

tzinfo

fold

date()

time()

timetz()

replace()

astimezone()

utcoffset()

dst()

tzname()

timetuple()

utctimetuple()

toordinal()

timestamp()

weekday()

isoweekday()

isocalendar()

isoformat()

__str__()

ctime()

strftime()

__format__()

사용 예: datetime

time 객체

time

min

max

resolution

hour

minute

second

microsecond

tzinfo

fold

fromisoformat()

strptime()

replace()

isoformat()

__str__()

strftime()

__format__()

utcoffset()

dst()

tzname()

사용 예: time

tzinfo 객체

tzinfo

utcoffset()

dst()

tzname()

fromutc()

timezone 객체

timezone

utcoffset()

tzname()

dst()

fromutc()

utc

strftime() and strptime() Behavior

strftime() and strptime() Format Codes

기술적 세부 사항

zoneinfo — IANA time zone support

ZoneInfo 사용하기

데이터 소스

데이터 소스 구성

컴파일 시간 구성

환경 구성

실행 시간 구성

ZoneInfo 클래스

ZoneInfo

from_file()

no_cache()

clear_cache()

key

문자열 표현

피클 직렬화

함수

available_timezones()

reset_tzpath()

전역

TZPATH

예외와 경고

ZoneInfoNotFoundError

InvalidTZPathWarning

calendar — General calendar-related functions

Calendar

iterweekdays()

itermonthdates()

itermonthdays()

itermonthdays2()

itermonthdays3()

itermonthdays4()

monthdatescalendar()

monthdays2calendar()

monthdayscalendar()

yeardatescalendar()

yeardays2calendar()

yeardayscalendar()

TextCalendar

formatmonth()

prmonth()

formatyear()

pryear()

HTMLCalendar

formatmonth()

formatyear()

formatyearpage()

formatmonthname()

cssclasses

cssclass_noday

cssclasses_weekday_head

cssclass_month_head

cssclass_month

cssclass_year

cssclass_year_head

LocaleTextCalendar

LocaleHTMLCalendar

setfirstweekday()

firstweekday()

isleap()

leapdays()

weekday()

weekheader()

monthrange()

monthcalendar()

prmonth()

month()

prcal()

calendar()

timegm()

day_name

day_abbr

MONDAY

TUESDAY

WEDNESDAY

THURSDAY

FRIDAY

SATURDAY

SUNDAY

Day

month_name

month_abbr

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

JULY

AUGUST

SEPTEMBER

OCTOBER

NOVEMBER

DECEMBER

Month

IllegalMonthError

month

IllegalWeekdayError

weekday

Command-Line Usage

collections — Container datatypes

ChainMap 객체

ChainMap

maps

new_child()

parents

ChainMap 예제와 조리법

Counter 객체

Counter

elements()

most_common()

subtract()

total()

fromkeys()

update()

deque 객체

deque

append()

appendleft()

clear()

copy()

count()

extend()

extendleft()

index()

insert()

pop()

popleft()

remove()

reverse()

rotate()

maxlen

deque 조리법

defaultdict 객체

defaultdict

__missing__()

default_factory

defaultdict 예

이름있는 필드를 가진 튜플을 위한 namedtuple() 팩토리 함수

namedtuple()

_make()

_asdict()

_replace()

_fields

_field_defaults

OrderedDict 객체

OrderedDict

popitem()

move_to_end()

OrderedDict 예제와 조리법

UserDict 객체

UserDict

data

UserList 객체

UserList

data

UserString 객체

UserString

data

collections.abc — Abstract Base Classes for Containers

Collections 추상 베이스 클래스

Collections Abstract Base Classes – Detailed Descriptions

Container

Hashable

Sized

Callable

Iterable

Collection

Iterator

Reversible

Generator

Sequence

MutableSequence

Set

MutableSet

Mapping

MutableMapping

MappingView

ItemsView

KeysView

ValuesView

Awaitable

Coroutine

AsyncIterable

AsyncIterator

AsyncGenerator

Buffer

Examples and Recipes

heapq — Heap queue algorithm

heappush()

heappop()

heappushpop()

heapify()

heapreplace()

merge()

nlargest()

nsmallest()

기본 예

우선순위 큐 구현 참고 사항

이론

bisect — Array bisection algorithm

bisect_left()

bisect_right()

bisect()

insort_left()

insort_right()

insort()

Performance Notes

정렬된 리스트 검색하기

Examples

array — Efficient arrays of numeric values

typecodes

array

typecode

itemsize

append()

buffer_info()

byteswap()

count()

extend()

frombytes()

fromfile()

fromlist()

fromunicode()

index()

insert()

pop()

remove()

clear()

reverse()

tobytes()

tofile()

tolist()

tounicode()

weakref — 약한 참조

ref

__callback__

proxy()

getweakrefcount()

getweakrefs()

WeakKeyDictionary

keyrefs()

WeakValueDictionary

valuerefs()

WeakSet

WeakMethod

finalize

__call__()

detach()

peek()

alive

atexit

ReferenceType

ProxyType

CallableProxyType

ProxyTypes

약한 참조 객체

예

파이널라이저 객체

Comparing finalizers with __del__() methods

types — Dynamic type creation and names for built-in types

동적 형 생성

new_class()

prepare_class()

resolve_bases()

get_original_bases()

표준 인터프리터 형

NoneType

FunctionType

LambdaType

GeneratorType

CoroutineType

AsyncGeneratorType

CodeType

CellType

MethodType

BuiltinFunctionType

BuiltinMethodType

WrapperDescriptorType

MethodWrapperType

NotImplementedType

MethodDescriptorType

ClassMethodDescriptorType

ModuleType

EllipsisType

GenericAlias

UnionType

TracebackType

FrameType

GetSetDescriptorType

MemberDescriptorType

MappingProxyType

copy()

get()

items()

keys()

values()

CapsuleType

추가 유틸리티 클래스와 함수

SimpleNamespace

DynamicClassAttribute()

코루틴 유틸리티 함수

coroutine()

copy — Shallow and deep copy operations

copy()

deepcopy()

replace()

Error

__copy__()

__deepcopy__()

__replace__()

pprint — Data pretty printer

Functions

pp()

pprint()

pformat()

isreadable()

isrecursive()

saferepr()

PrettyPrinter 객체

PrettyPrinter

pformat()

pprint()

isreadable()

isrecursive()

format()

예제

reprlib — Alternate repr() implementation

Repr

aRepr

repr()

recursive_repr()

Repr 객체

fillvalue

maxlevel

maxdict

maxlist

maxtuple

maxset

maxfrozenset

maxdeque

maxarray

maxlong

maxstring

maxother

indent

repr()

repr1()

Repr 객체 서브 클래싱

enum — Support for enumerations

모듈 내용

Data Types

EnumType

__call__()

__contains__()

__dir__()

__getitem__()

__iter__()

__len__()

__members__

__reversed__()

_add_alias_()

_add_value_alias_()

Enum

name

value

_name_

_value_

_order_

_ignore_

__dir__()

_generate_next_value_()

__init__()

__init_subclass__()

_missing_()

__new__()

__repr__()

__str__()

__format__()

IntEnum

StrEnum

Flag

__contains__()

__or__()

__and__()

__xor__()

_numeric_repr_()

IntFlag

ReprEnum

EnumCheck

UNIQUE

CONTINUOUS

NAMED_FLAGS

FlagBoundary

STRICT

CONFORM

EJECT

KEEP

지원되는 __dunder__ 이름

지원되는 _sunder_ 이름

Utilities and Decorators

auto

property()

unique()

verify()

member()

nonmember()

global_enum()

show_flag_values()

Notes

graphlib — Functionality to operate with graph-like structures

TopologicalSorter

add()

prepare()

is_active()

done()

get_ready()

static_order()

예외

CycleError

숫자와 수학 모듈

numbers — Numeric abstract base classes

Number

숫자 계층

Complex

real

imag

conjugate()

Real

Rational

numerator

denominator

Integral

Notes for type implementers

더 많은 숫자 추상 베이스 클래스(ABC) 추가

산술 연산 구현

math — Mathematical functions

Number-theoretic functions

comb()

factorial()

gcd()

isqrt()

lcm()

perm()

Floating point arithmetic

ceil()

fabs()

floor()

fma()

fmod()

modf()

remainder()

trunc()

Floating point manipulation functions

copysign()

frexp()

isclose()

isfinite()

isinf()

isnan()

ldexp()

nextafter()

ulp()

Power, exponential and logarithmic functions

cbrt()

exp()

exp2()

expm1()

log()

log1p()

log2()

log10()

pow()

sqrt()

Summation and product functions

dist()

fsum()

hypot()

prod()

sumprod()

각도 변환

degrees()

radians()

삼각 함수

acos()

asin()

atan()

atan2()

cos()

sin()

tan()

쌍곡선 함수

acosh()

asinh()

atanh()

cosh()

sinh()

tanh()

특수 함수

erf()

erfc()

gamma()

lgamma()

상수

pi

e

tau

inf

nan

cmath — Mathematical functions for complex numbers

극좌표 변환

phase()

polar()

rect()

거듭제곱과 로그 함수

exp()

log()

log10()

sqrt()

삼각 함수

acos()

asin()

atan()

cos()

sin()

tan()

쌍곡선(hyperbolic) 함수

acosh()

asinh()

atanh()

cosh()

sinh()

tanh()

분류 함수

isfinite()

isinf()

isnan()

isclose()

상수

pi

e

tau

inf

infj

nan

nanj

decimal — Decimal fixed-point and floating-point arithmetic

빠른 시작 자습서

Decimal 객체

Decimal

adjusted()

as_integer_ratio()

as_tuple()

canonical()

compare()

compare_signal()

compare_total()

compare_total_mag()

conjugate()

copy_abs()

copy_negate()

copy_sign()

exp()

from_float()

from_number()

fma()

is_canonical()

is_finite()

is_infinite()

is_nan()

is_normal()

is_qnan()

is_signed()

is_snan()

is_subnormal()

is_zero()

ln()

log10()

logb()

logical_and()

logical_invert()

logical_or()

logical_xor()

max()

max_mag()

min()

min_mag()

next_minus()

next_plus()

next_toward()

normalize()

number_class()

quantize()

radix()

remainder_near()

rotate()

same_quantum()

scaleb()

shift()

sqrt()

to_eng_string()

to_integral()

to_integral_exact()

to_integral_value()

논리적 피연산자

Context 객체

getcontext()

setcontext()

localcontext()

BasicContext

ExtendedContext

DefaultContext

Context

clear_flags()

clear_traps()

copy()

copy_decimal()

create_decimal()

create_decimal_from_float()

Etiny()

Etop()

abs()

add()

canonical()

compare()

compare_signal()

compare_total()

compare_total_mag()

copy_abs()

copy_negate()

copy_sign()

divide()

divide_int()

divmod()

exp()

fma()

is_canonical()

is_finite()

is_infinite()

is_nan()

is_normal()

is_qnan()

is_signed()

is_snan()

is_subnormal()

is_zero()

ln()

log10()

logb()

logical_and()

logical_invert()

logical_or()

logical_xor()

max()

max_mag()

min()

min_mag()

minus()

multiply()

next_minus()

next_plus()

next_toward()

normalize()

number_class()

plus()

power()

quantize()

radix()

remainder()

remainder_near()

rotate()

same_quantum()

scaleb()

shift()

sqrt()

subtract()

to_eng_string()

to_integral_exact()

to_sci_string()

상수

MAX_PREC

MAX_EMAX

MIN_EMIN

MIN_ETINY

HAVE_THREADS

HAVE_CONTEXTVAR

자리 올림 모드

ROUND_CEILING

ROUND_DOWN

ROUND_FLOOR

ROUND_HALF_DOWN

ROUND_HALF_EVEN

ROUND_HALF_UP

ROUND_UP

ROUND_05UP

신호

Clamped

DecimalException

DivisionByZero

Inexact

InvalidOperation

Overflow

Rounded

Subnormal

Underflow

FloatOperation

Floating-Point Notes

증가시킨 정밀도로 자리 올림 오차 줄이기

특수 값

스레드로 작업하기

조리법

Decimal FAQ

fractions — Rational numbers

Fraction

numerator

denominator

as_integer_ratio()

is_integer()

from_float()

from_decimal()

from_number()

limit_denominator()

__floor__()

__ceil__()

__round__()

__format__()

random — Generate pseudo-random numbers

관리 함수

seed()

getstate()

setstate()

바이트열 함수

randbytes()

정수 함수

randrange()

randint()

getrandbits()

시퀀스 함수

choice()

choices()

shuffle()

sample()

Discrete distributions

binomialvariate()

실수 분포

random()

uniform()

triangular()

betavariate()

expovariate()

gammavariate()

gauss()

lognormvariate()

normalvariate()

vonmisesvariate()

paretovariate()

weibullvariate()

대체 생성기

Random

seed()

getstate()

setstate()

random()

getrandbits()

SystemRandom

재현성에 대한 참고 사항

예제

조리법

Command-line usage

Command-line example

statistics — Mathematical statistics functions

평균과 중심 위치의 측정

분산 측정

Statistics for relations between two inputs

함수 세부 사항

mean()

fmean()

geometric_mean()

harmonic_mean()

kde()

kde_random()

median()

median_low()

median_high()

median_grouped()

mode()

multimode()

pstdev()

pvariance()

stdev()

variance()

quantiles()

covariance()

correlation()

linear_regression()

예외

StatisticsError

NormalDist 객체

NormalDist

mean

median

mode

stdev

variance

from_samples()

samples()

pdf()

cdf()

inv_cdf()

overlap()

quantiles()

zscore()

Examples and Recipes

Classic probability problems

Monte Carlo inputs for simulations

Approximating binomial distributions

Naive bayesian classifier

함수형 프로그래밍 모듈

itertools — Functions creating iterators for efficient looping

Itertool Functions

accumulate()

batched()

chain()

from_iterable()

combinations()

combinations_with_replacement()

compress()

count()

cycle()

dropwhile()

filterfalse()

groupby()

islice()

pairwise()

permutations()

product()

repeat()

starmap()

takewhile()

tee()

zip_longest()

Itertools 조리법

functools — Higher-order functions and operations on callable objects

cache()

cached_property()

cmp_to_key()

lru_cache()

total_ordering()

Placeholder

partial()

partialmethod

reduce()

singledispatch()

singledispatchmethod

update_wrapper()

wraps()

partial 객체

func

args

keywords

operator — Standard operators as functions

lt()

le()

eq()

ne()

ge()

gt()

__lt__()

__le__()

__eq__()

__ne__()

__ge__()

__gt__()

not_()

__not__()

truth()

is_()

is_not()

is_none()

is_not_none()

abs()

__abs__()

add()

__add__()

and_()

__and__()

floordiv()

__floordiv__()

index()

__index__()

inv()

invert()

__inv__()

__invert__()

lshift()

__lshift__()

mod()

__mod__()

mul()

__mul__()

matmul()

__matmul__()

neg()

__neg__()

or_()

__or__()

pos()

__pos__()

pow()

__pow__()

rshift()

__rshift__()

sub()

__sub__()

truediv()

__truediv__()

xor()

__xor__()

concat()

__concat__()

contains()

__contains__()

countOf()

delitem()

__delitem__()

getitem()

__getitem__()

indexOf()

setitem()

__setitem__()

length_hint()

call()

__call__()

attrgetter()

itemgetter()

methodcaller()

연산자를 함수에 매핑하기

제자리 연산자

iadd()

__iadd__()

iand()

__iand__()

iconcat()

__iconcat__()

ifloordiv()

__ifloordiv__()

ilshift()

__ilshift__()

imod()

__imod__()

imul()

__imul__()

imatmul()

__imatmul__()

ior()

__ior__()

ipow()

__ipow__()

irshift()

__irshift__()

isub()

__isub__()

itruediv()

__itruediv__()

ixor()

__ixor__()

파일과 디렉터리 액세스

pathlib — Object-oriented filesystem paths

기본 사용

Exceptions

UnsupportedOperation

순수한 경로

PurePath

PurePosixPath

PureWindowsPath

일반 속성

연산자

개별 부분에 액세스하기

parts

메서드와 프로퍼티

parser

drive

root

anchor

parents

parent

name

suffix

suffixes

stem

as_posix()

is_absolute()

is_relative_to()

is_reserved()

joinpath()

full_match()

match()

relative_to()

with_name()

with_stem()

with_suffix()

with_segments()

구상 경로

Path

PosixPath

WindowsPath

Parsing and generating URIs

from_uri()

as_uri()

Expanding and resolving paths

home()

expanduser()

cwd()

absolute()

resolve()

readlink()

Querying file type and status

stat()

lstat()

exists()

is_file()

is_dir()

is_symlink()

is_junction()

is_mount()

is_socket()

is_fifo()

is_block_device()

is_char_device()

samefile()

Reading and writing files

open()

read_text()

read_bytes()

write_text()

write_bytes()

Reading directories

iterdir()

scandir()

glob()

rglob()

walk()

Creating files and directories

touch()

mkdir()

symlink_to()

hardlink_to()

Copying, moving and deleting

copy()

copy_into()

rename()

replace()

move()

move_into()

unlink()

rmdir()

Permissions and ownership

owner()

group()

chmod()

lchmod()

Pattern language

Comparison to the glob module

Comparison to the os and os.path modules

Corresponding tools

os.path — Common pathname manipulations

abspath()

basename()

commonpath()

commonprefix()

dirname()

exists()

lexists()

expanduser()

expandvars()

getatime()

getmtime()

getctime()

getsize()

isabs()

isfile()

isdir()

isjunction()

islink()

ismount()

isdevdrive()

isreserved()

join()

normcase()

normpath()

realpath()

relpath()

samefile()

sameopenfile()

samestat()

split()

splitdrive()

splitroot()

splitext()

supports_unicode_filenames

fileinput — Iterate over lines from multiple input streams

input()

filename()

fileno()

lineno()

filelineno()

isfirstline()

isstdin()

nextfile()

close()

FileInput

hook_compressed()

hook_encoded()

stat — Interpreting stat() results

S_ISDIR()

S_ISCHR()

S_ISBLK()

S_ISREG()

S_ISFIFO()

S_ISLNK()

S_ISSOCK()

S_ISDOOR()

S_ISPORT()

S_ISWHT()

S_IMODE()

S_IFMT()

filemode()

ST_MODE

ST_INO

ST_DEV

ST_NLINK

ST_UID

ST_GID

ST_SIZE

ST_ATIME

ST_MTIME

ST_CTIME

S_IFSOCK

S_IFLNK

S_IFREG

S_IFBLK

S_IFDIR

S_IFCHR

S_IFIFO

S_IFDOOR

S_IFPORT

S_IFWHT

S_ISUID

S_ISGID

S_ISVTX

S_IRWXU

S_IRUSR

S_IWUSR

S_IXUSR

S_IRWXG

S_IRGRP

S_IWGRP

S_IXGRP

S_IRWXO

S_IROTH

S_IWOTH

S_IXOTH

S_ENFMT

S_IREAD

S_IWRITE

S_IEXEC

UF_SETTABLE

UF_NODUMP

UF_IMMUTABLE

UF_APPEND

UF_OPAQUE

UF_NOUNLINK

UF_COMPRESSED

UF_TRACKED

UF_DATAVAULT

UF_HIDDEN

SF_SETTABLE

SF_SUPPORTED

SF_SYNTHETIC

SF_ARCHIVED

SF_IMMUTABLE

SF_APPEND

SF_RESTRICTED

SF_NOUNLINK

SF_SNAPSHOT

SF_FIRMLINK

SF_DATALESS

FILE_ATTRIBUTE_ARCHIVE

FILE_ATTRIBUTE_COMPRESSED

FILE_ATTRIBUTE_DEVICE

FILE_ATTRIBUTE_DIRECTORY

FILE_ATTRIBUTE_ENCRYPTED

FILE_ATTRIBUTE_HIDDEN

FILE_ATTRIBUTE_INTEGRITY_STREAM

FILE_ATTRIBUTE_NORMAL

FILE_ATTRIBUTE_NOT_CONTENT_INDEXED

FILE_ATTRIBUTE_NO_SCRUB_DATA

FILE_ATTRIBUTE_OFFLINE

FILE_ATTRIBUTE_READONLY

FILE_ATTRIBUTE_REPARSE_POINT

FILE_ATTRIBUTE_SPARSE_FILE

FILE_ATTRIBUTE_SYSTEM

FILE_ATTRIBUTE_TEMPORARY

FILE_ATTRIBUTE_VIRTUAL

IO_REPARSE_TAG_SYMLINK

IO_REPARSE_TAG_MOUNT_POINT

IO_REPARSE_TAG_APPEXECLINK

filecmp — File and Directory Comparisons

cmp()

cmpfiles()

clear_cache()

dircmp 클래스

dircmp

report()

report_partial_closure()

report_full_closure()

left

right

left_list

right_list

common

left_only

right_only

common_dirs

common_files

common_funny

same_files

diff_files

funny_files

subdirs

DEFAULT_IGNORES

tempfile — Generate temporary files and directories

TemporaryFile()

NamedTemporaryFile()

SpooledTemporaryFile

rollover()

TemporaryDirectory

name

cleanup()

mkstemp()

mkdtemp()

gettempdir()

gettempdirb()

gettempprefix()

gettempprefixb()

tempdir

예

폐지된 함수와 변수

mktemp()

glob — Unix style pathname pattern expansion

glob()

iglob()

escape()

translate()

Examples

fnmatch — Unix filename pattern matching

fnmatch()

fnmatchcase()

filter()

translate()

linecache — Random access to text lines

getline()

clearcache()

checkcache()

lazycache()

shutil — High-level file operations

디렉터리와 파일 연산

copyfileobj()

copyfile()

SameFileError

copymode()

copystat()

copy()

copy2()

ignore_patterns()

copytree()

rmtree()

avoids_symlink_attacks

move()

disk_usage()

chown()

which()

Error

플랫폼 의존적 효율적인 복사 연산

copytree 예

rmtree 예

아카이브 연산

make_archive()

get_archive_formats()

register_archive_format()

unregister_archive_format()

unpack_archive()

register_unpack_format()

unregister_unpack_format()

get_unpack_formats()

아카이브 예

base_dir을 사용한 아카이브 예

출력 터미널의 크기 조회하기

get_terminal_size()

데이터 지속성

pickle — Python object serialization

다른 파이썬 모듈과의 관계

marshal 과의 비교

json 과의 비교

데이터 스트림 형식

모듈 인터페이스

HIGHEST_PROTOCOL

DEFAULT_PROTOCOL

dump()

dumps()

load()

loads()

PickleError

PicklingError

UnpicklingError

Pickler

dump()

persistent_id()

dispatch_table

reducer_override()

fast

Unpickler

load()

persistent_load()

find_class()

PickleBuffer

raw()

release()

어떤 것이 피클 되고 역 피클 될 수 있을까요?

클래스 인스턴스 피클링

__getnewargs_ex__()

__getnewargs__()

__getstate__()

__setstate__()

__reduce__()

__reduce_ex__()

외부 객체의 지속성

디스패치 테이블

상태 저장 객체 처리

형, 함수 및 기타 객체에 대한 사용자 정의 환원

아웃 오브 밴드 버퍼

제공자 API

소비자 API

예제

전역 제한하기

성능

예제

copyreg — Register pickle support functions

constructor()

pickle()

예제

shelve — Python object persistence

open()

sync()

close()

제약 사항

Shelf

BsdDbShelf

DbfilenameShelf

예제

marshal — Internal Python object serialization

dump()

load()

dumps()

loads()

version

dbm — Interfaces to Unix “databases”

error

whichdb()

open()

dbm.sqlite3 — SQLite backend for dbm

open()

dbm.gnu — GNU database manager

error

open()

open_flags

firstkey()

nextkey()

reorganize()

sync()

close()

clear()

dbm.ndbm — New Database Manager

error

library

open()

close()

clear()

dbm.dumb — 이식성 있는 DBM 구현

error

open()

sync()

close()

sqlite3 — DB-API 2.0 interface for SQLite databases

Tutorial

Reference

Module functions

connect()

complete_statement()

enable_callback_tracebacks()

register_adapter()

register_converter()

Module constants

LEGACY_TRANSACTION_CONTROL

PARSE_COLNAMES

PARSE_DECLTYPES

SQLITE_OK

SQLITE_DENY

SQLITE_IGNORE

apilevel

paramstyle

sqlite_version

sqlite_version_info

threadsafety

SQLITE_DBCONFIG_DEFENSIVE

SQLITE_DBCONFIG_DQS_DDL

SQLITE_DBCONFIG_DQS_DML

SQLITE_DBCONFIG_ENABLE_FKEY

SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER

SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION

SQLITE_DBCONFIG_ENABLE_QPSG

SQLITE_DBCONFIG_ENABLE_TRIGGER

SQLITE_DBCONFIG_ENABLE_VIEW

SQLITE_DBCONFIG_LEGACY_ALTER_TABLE

SQLITE_DBCONFIG_LEGACY_FILE_FORMAT

SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE

SQLITE_DBCONFIG_RESET_DATABASE

SQLITE_DBCONFIG_TRIGGER_EQP

SQLITE_DBCONFIG_TRUSTED_SCHEMA

SQLITE_DBCONFIG_WRITABLE_SCHEMA

Connection objects

Connection

cursor()

blobopen()

commit()

rollback()

close()

execute()

executemany()

executescript()

create_function()

create_aggregate()

create_window_function()

create_collation()

interrupt()

set_authorizer()

set_progress_handler()

set_trace_callback()

enable_load_extension()

load_extension()

iterdump()

backup()

getlimit()

setlimit()

getconfig()

setconfig()

serialize()

deserialize()

autocommit

in_transaction

isolation_level

row_factory

text_factory

total_changes

Cursor objects

Cursor

execute()

executemany()

executescript()

fetchone()

fetchmany()

fetchall()

close()

setinputsizes()

setoutputsize()

arraysize

connection

description

lastrowid

rowcount

row_factory

Row objects

Row

keys()

Blob objects

Blob

close()

read()

write()

tell()

seek()

PrepareProtocol objects

PrepareProtocol

예외

Warning

Error

sqlite_errorcode

sqlite_errorname

InterfaceError

DatabaseError

DataError

OperationalError

IntegrityError

InternalError

ProgrammingError

NotSupportedError

SQLite 와 파이썬 형

Default adapters and converters (deprecated)

Command-line interface

How-to guides

How to use placeholders to bind values in SQL queries

How to adapt custom Python types to SQLite values

How to write adaptable objects

How to register adapter callables

How to convert SQLite values to custom Python types

Adapter and converter recipes

How to use connection shortcut methods

How to use the connection context manager

How to work with SQLite URIs

How to create and use row factories

How to handle non-UTF-8 text encodings

Explanation

Transaction control

Transaction control via the autocommit attribute

Transaction control via the isolation_level attribute

데이터 압축 및 보관

zlib — Compression compatible with gzip

error

adler32()

compress()

compressobj()

crc32()

decompress()

decompressobj()

compress()

flush()

copy()

unused_data

unconsumed_tail

eof

decompress()

flush()

copy()

ZLIB_VERSION

ZLIB_RUNTIME_VERSION

gzip — Support for gzip files

open()

BadGzipFile

GzipFile

peek()

mode

mtime

name

compress()

decompress()

사용 예

명령 줄 인터페이스

명령 줄 옵션

bz2 — Support for bzip2 compression

파일 압축(해제)

open()

BZ2File

peek()

fileno()

readable()

seekable()

writable()

read1()

readinto()

mode

name

증분 압축(해제)

BZ2Compressor

compress()

flush()

BZ2Decompressor

decompress()

eof

unused_data

needs_input

일괄 압축(해제)

compress()

decompress()

사용 예

lzma — Compression using the LZMA algorithm

LZMAError

압축 파일 읽기와 쓰기

open()

LZMAFile

peek()

mode

name

메모리에서의 데이터 압축과 압축 해제

LZMACompressor

compress()

flush()

LZMADecompressor

decompress()

check

eof

unused_data

needs_input

compress()

decompress()

기타

is_check_supported()

사용자 정의 필터 체인 지정

예

zipfile — Work with ZIP archives

BadZipFile

BadZipfile

LargeZipFile

ZipInfo

is_zipfile()

ZIP_STORED

ZIP_DEFLATED

ZIP_BZIP2

ZIP_LZMA

ZipFile 객체

ZipFile

close()

getinfo()

infolist()

namelist()

open()

extract()

extractall()

printdir()

setpassword()

read()

testzip()

write()

writestr()

mkdir()

filename

debug

comment

Path 객체

Path

name

open()

iterdir()

is_dir()

is_file()

is_symlink()

exists()

suffix

stem

suffixes

read_text()

read_bytes()

joinpath()

PyZipFile 객체

PyZipFile

writepy()

ZipInfo 객체

from_file()

is_dir()

filename

date_time

compress_type

comment

extra

create_system

create_version

extract_version

reserved

flag_bits

volume

internal_attr

external_attr

header_offset

CRC

compress_size

file_size

명령 줄 인터페이스

명령 줄 옵션

압축 해제 함정

파일 자체에서

파일 시스템 제한

자원 제한

중단

추출의 기본 동작

tarfile — Read and write tar archive files

open()

is_tarfile()

TarError

ReadError

CompressionError

StreamError

ExtractError

HeaderError

FilterError

tarinfo

AbsolutePathError

OutsideDestinationError

SpecialFileError

AbsoluteLinkError

LinkOutsideDestinationError

ENCODING

REGTYPE

AREGTYPE

LNKTYPE

SYMTYPE

CHRTYPE

BLKTYPE

DIRTYPE

FIFOTYPE

CONTTYPE

GNUTYPE_LONGNAME

GNUTYPE_LONGLINK

GNUTYPE_SPARSE

USTAR_FORMAT

GNU_FORMAT

PAX_FORMAT

DEFAULT_FORMAT

TarFile 객체

TarFile

open()

getmember()

getmembers()

getnames()

list()

next()

extractall()

extract()

extractfile()

errorlevel

extraction_filter

add()

addfile()

gettarinfo()

close()

pax_headers

TarInfo 객체

TarInfo

frombuf()

fromtarfile()

tobuf()

name

size

mtime

mode

type

linkname

uid

gid

uname

gname

chksum

devmajor

devminor

offset

offset_data

sparse

pax_headers

replace()

isfile()

isreg()

isdir()

issym()

islnk()

ischr()

isblk()

isfifo()

isdev()

Extraction filters

Default named filters

fully_trusted_filter()

tar_filter()

data_filter()

Filter errors

Hints for further verification

Supporting older Python versions

Stateful extraction filter example

명령 줄 인터페이스

명령 줄 옵션

예

지원되는 tar 형식

유니코드 문제

파일 형식

csv — CSV File Reading and Writing

모듈 내용

reader()

writer()

register_dialect()

unregister_dialect()

get_dialect()

list_dialects()

field_size_limit()

DictReader

DictWriter

Dialect

excel

excel_tab

unix_dialect

Sniffer

sniff()

has_header()

QUOTE_ALL

QUOTE_MINIMAL

QUOTE_NONNUMERIC

QUOTE_NONE

QUOTE_NOTNULL

QUOTE_STRINGS

Error

방언과 포매팅 파라미터

delimiter

doublequote

escapechar

lineterminator

quotechar

quoting

skipinitialspace

strict

판독기 객체

__next__()

dialect

line_num

fieldnames

기록기 객체

writerow()

writerows()

dialect

writeheader()

예제

configparser — Configuration file parser

빠른 시작

지원되는 데이터형

대체 값

지원되는 INI 파일 구조

Unnamed Sections

값의 보간

BasicInterpolation

ExtendedInterpolation

매핑 프로토콜 액세스

구문 분석기 동작 사용자 정의

BOOLEAN_STATES

SECTCRE

레거시 API 예제

ConfigParser 객체

ConfigParser

defaults()

sections()

add_section()

has_section()

options()

has_option()

read()

read_file()

read_string()

read_dict()

get()

getint()

getfloat()

getboolean()

items()

set()

write()

remove_option()

remove_section()

optionxform()

UNNAMED_SECTION

MAX_INTERPOLATION_DEPTH

RawConfigParser 객체

RawConfigParser

add_section()

set()

예외

Error

NoSectionError

DuplicateSectionError

DuplicateOptionError

NoOptionError

InterpolationError

InterpolationDepthError

InterpolationMissingOptionError

InterpolationSyntaxError

MissingSectionHeaderError

ParsingError

MultilineContinuationError

UnnamedSectionDisabledError

tomllib — Parse TOML files

load()

loads()

TOMLDecodeError

msg

doc

pos

lineno

colno

Examples

Conversion Table

netrc — netrc file processing

netrc

NetrcParseError

msg

filename

lineno

netrc 객체

authenticators()

__repr__()

hosts

macros

plistlib — Generate and parse Apple .plist files

load()

loads()

dump()

dumps()

UID

FMT_XML

FMT_BINARY

예제

암호화 서비스

hashlib — Secure hashes and message digests

해시 알고리즘

Usage

Constructors

new()

md5()

sha1()

sha224()

sha256()

sha384()

sha512()

sha3_224()

sha3_256()

sha3_384()

sha3_512()

Attributes

algorithms_guaranteed

algorithms_available

Hash Objects

digest_size

block_size

name

update()

digest()

hexdigest()

copy()

SHAKE 가변 길이 요약

shake_128()

shake_256()

digest()

hexdigest()

File hashing

file_digest()

키 파생

pbkdf2_hmac()

scrypt()

BLAKE2

해시 객체 만들기

blake2b()

blake2s()

상수

SALT_SIZE

SALT_SIZE

PERSON_SIZE

PERSON_SIZE

MAX_KEY_SIZE

MAX_KEY_SIZE

MAX_DIGEST_SIZE

MAX_DIGEST_SIZE

예

간단한 해싱

다른 요약 크기 사용하기

키 해싱

무작위 해싱

개인화

트리 모드

크레딧

hmac — Keyed-Hashing for Message Authentication

new()

digest()

update()

digest()

hexdigest()

copy()

digest_size

block_size

name

compare_digest()

secrets — Generate secure random numbers for managing secrets

난수

SystemRandom

choice()

randbelow()

randbits()

토큰 생성

token_bytes()

token_hex()

token_urlsafe()

토큰은 몇 바이트를 사용해야 합니까?

기타 함수

compare_digest()

조리법과 모범 사례

일반 운영 체제 서비스

os — Miscellaneous operating system interfaces

error

name

파일명, 명령 줄 인자 및 환경 변수

Python UTF-8 Mode

프로세스 매개 변수

ctermid()

environ

environb

reload_environ()

fsencode()

fsdecode()

fspath()

PathLike

__fspath__()

getenv()

getenvb()

get_exec_path()

getegid()

geteuid()

getgid()

getgrouplist()

getgroups()

getlogin()

getpgid()

getpgrp()

getpid()

getppid()

getpriority()

PRIO_PROCESS

PRIO_PGRP

PRIO_USER

PRIO_DARWIN_THREAD

PRIO_DARWIN_PROCESS

PRIO_DARWIN_BG

PRIO_DARWIN_NONUI

getresuid()

getresgid()

getuid()

initgroups()

putenv()

setegid()

seteuid()

setgid()

setgroups()

setns()

setpgrp()

setpgid()

setpriority()

setregid()

setresgid()

setresuid()

setreuid()

getsid()

setsid()

setuid()

strerror()

supports_bytes_environ

umask()

uname()

unsetenv()

unshare()

CLONE_FILES

CLONE_FS

CLONE_NEWCGROUP

CLONE_NEWIPC

CLONE_NEWNET

CLONE_NEWNS

CLONE_NEWPID

CLONE_NEWTIME

CLONE_NEWUSER

CLONE_NEWUTS

CLONE_SIGHAND

CLONE_SYSVSEM

CLONE_THREAD

CLONE_VM

파일 객체 생성

fdopen()

파일 기술자 연산

close()

closerange()

copy_file_range()

device_encoding()

dup()

dup2()

fchmod()

fchown()

fdatasync()

fpathconf()

fstat()

fstatvfs()

fsync()

ftruncate()

get_blocking()

grantpt()

isatty()

lockf()

F_LOCK

F_TLOCK

F_ULOCK

F_TEST

login_tty()

lseek()

SEEK_SET

SEEK_CUR

SEEK_END

SEEK_HOLE

SEEK_DATA

open()

O_RDONLY

O_WRONLY

O_RDWR

O_APPEND

O_CREAT

O_EXCL

O_TRUNC

O_DSYNC

O_RSYNC

O_SYNC

O_NDELAY

O_NONBLOCK

O_NOCTTY

O_CLOEXEC

O_BINARY

O_NOINHERIT

O_SHORT_LIVED

O_TEMPORARY

O_RANDOM

O_SEQUENTIAL

O_TEXT

O_EVTONLY

O_FSYNC

O_SYMLINK

O_NOFOLLOW_ANY

O_ASYNC

O_DIRECT

O_DIRECTORY

O_NOFOLLOW

O_NOATIME

O_PATH

O_TMPFILE

O_SHLOCK

O_EXLOCK

openpty()

pipe()

pipe2()

posix_fallocate()

posix_fadvise()

POSIX_FADV_NORMAL

POSIX_FADV_SEQUENTIAL

POSIX_FADV_RANDOM

POSIX_FADV_NOREUSE

POSIX_FADV_WILLNEED

POSIX_FADV_DONTNEED

pread()

posix_openpt()

preadv()

RWF_NOWAIT

RWF_HIPRI

ptsname()

pwrite()

pwritev()

RWF_DSYNC

RWF_SYNC

RWF_APPEND

read()

sendfile()

SF_NODISKIO

SF_MNOWAIT

SF_SYNC

SF_NOCACHE

set_blocking()

splice()

SPLICE_F_MOVE

SPLICE_F_NONBLOCK

SPLICE_F_MORE

readv()

tcgetpgrp()

tcsetpgrp()

ttyname()

unlockpt()

write()

writev()

터미널의 크기 조회하기

get_terminal_size()

terminal_size

columns

lines

파일 기술자의 상속

get_inheritable()

set_inheritable()

get_handle_inheritable()

set_handle_inheritable()

파일과 디렉터리

access()

F_OK

R_OK

W_OK

X_OK

chdir()

chflags()

chmod()

chown()

chroot()

fchdir()

getcwd()

getcwdb()

lchflags()

lchmod()

lchown()

link()

listdir()

listdrives()

listmounts()

listvolumes()

lstat()

mkdir()

makedirs()

mkfifo()

mknod()

major()

minor()

makedev()

pathconf()

pathconf_names

readlink()

remove()

removedirs()

rename()

renames()

replace()

rmdir()

scandir()

close()

DirEntry

name

path

inode()

is_dir()

is_file()

is_symlink()

is_junction()

stat()

stat()

stat_result

st_mode

st_ino

st_dev

st_nlink

st_uid

st_gid

st_size

st_atime

st_mtime

st_ctime

st_atime_ns

st_mtime_ns

st_ctime_ns

st_birthtime

st_birthtime_ns

st_blocks

st_blksize

st_rdev

st_flags

st_gen

st_fstype

st_rsize

st_creator

st_type

st_file_attributes

st_reparse_tag

statvfs()

supports_dir_fd

supports_effective_ids

supports_fd

supports_follow_symlinks

symlink()

sync()

truncate()

unlink()

utime()

walk()

fwalk()

memfd_create()

MFD_CLOEXEC

MFD_ALLOW_SEALING

MFD_HUGETLB

MFD_HUGE_SHIFT

MFD_HUGE_MASK

MFD_HUGE_64KB

MFD_HUGE_512KB

MFD_HUGE_1MB

MFD_HUGE_2MB

MFD_HUGE_8MB

MFD_HUGE_16MB

MFD_HUGE_32MB

MFD_HUGE_256MB

MFD_HUGE_512MB

MFD_HUGE_1GB

MFD_HUGE_2GB

MFD_HUGE_16GB

eventfd()

eventfd_read()

eventfd_write()

EFD_CLOEXEC

EFD_NONBLOCK

EFD_SEMAPHORE

Timer File Descriptors

timerfd_create()

timerfd_settime()

timerfd_settime_ns()

timerfd_gettime()

timerfd_gettime_ns()

TFD_NONBLOCK

TFD_CLOEXEC

TFD_TIMER_ABSTIME

TFD_TIMER_CANCEL_ON_SET

리눅스 확장 어트리뷰트

getxattr()

listxattr()

removexattr()

setxattr()

XATTR_SIZE_MAX

XATTR_CREATE

XATTR_REPLACE

프로세스 관리

abort()

add_dll_directory()

execl()

execle()

execlp()

execlpe()

execv()

execve()

execvp()

execvpe()

_exit()

EX_OK

EX_USAGE

EX_DATAERR

EX_NOINPUT

EX_NOUSER

EX_NOHOST

EX_UNAVAILABLE

EX_SOFTWARE

EX_OSERR

EX_OSFILE

EX_CANTCREAT

EX_IOERR

EX_TEMPFAIL

EX_PROTOCOL

EX_NOPERM

EX_CONFIG

EX_NOTFOUND

fork()

forkpty()

kill()

killpg()

nice()

pidfd_open()

PIDFD_NONBLOCK

plock()

popen()

posix_spawn()

POSIX_SPAWN_OPEN

POSIX_SPAWN_CLOSE

POSIX_SPAWN_DUP2

POSIX_SPAWN_CLOSEFROM

posix_spawnp()

register_at_fork()

spawnl()

spawnle()

spawnlp()

spawnlpe()

spawnv()

spawnve()

spawnvp()

spawnvpe()

P_NOWAIT

P_NOWAITO

P_WAIT

P_DETACH

P_OVERLAY

startfile()

system()

times()

wait()

waitid()

waitpid()

wait3()

wait4()

P_PID

P_PGID

P_ALL

P_PIDFD

WCONTINUED

WEXITED

WSTOPPED

WUNTRACED

WNOHANG

WNOWAIT

CLD_EXITED

CLD_KILLED

CLD_DUMPED

CLD_TRAPPED

CLD_STOPPED

CLD_CONTINUED

waitstatus_to_exitcode()

WCOREDUMP()

WIFCONTINUED()

WIFSTOPPED()

WIFSIGNALED()

WIFEXITED()

WEXITSTATUS()

WSTOPSIG()

WTERMSIG()

스케줄러에 대한 인터페이스

SCHED_OTHER

SCHED_BATCH

SCHED_IDLE

SCHED_SPORADIC

SCHED_FIFO

SCHED_RR

SCHED_RESET_ON_FORK

sched_param

sched_priority

sched_get_priority_min()

sched_get_priority_max()

sched_setscheduler()

sched_getscheduler()

sched_setparam()

sched_getparam()

sched_rr_get_interval()

sched_yield()

sched_setaffinity()

sched_getaffinity()

기타 시스템 정보

confstr()

confstr_names

cpu_count()

getloadavg()

process_cpu_count()

sysconf()

sysconf_names

curdir

pardir

sep

altsep

extsep

pathsep

defpath

linesep

devnull

RTLD_LAZY

RTLD_NOW

RTLD_GLOBAL

RTLD_LOCAL

RTLD_NODELETE

RTLD_NOLOAD

RTLD_DEEPBIND

난수

getrandom()

urandom()

GRND_NONBLOCK

GRND_RANDOM

io — Core tools for working with streams

개요

텍스트 I/O

바이너리 I/O

원시 I/O

Text Encoding

Opt-in EncodingWarning

고수준 모듈 인터페이스

DEFAULT_BUFFER_SIZE

open()

open_code()

text_encoding()

BlockingIOError

UnsupportedOperation

클래스 위계

I/O 베이스 클래스

IOBase

close()

closed

fileno()

flush()

isatty()

readable()

readline()

readlines()

seek()

seekable()

tell()

truncate()

writable()

writelines()

__del__()

RawIOBase

read()

readall()

readinto()

write()

BufferedIOBase

raw

detach()

read()

read1()

readinto()

readinto1()

write()

원시 파일 I/O

FileIO

mode

name

버퍼링 된 스트림

BytesIO

getbuffer()

getvalue()

read1()

readinto1()

BufferedReader

peek()

read()

read1()

BufferedWriter

flush()

write()

BufferedRandom

BufferedRWPair

텍스트 I/O

TextIOBase

encoding

errors

newlines

buffer

detach()

read()

readline()

seek()

tell()

write()

TextIOWrapper

line_buffering

write_through

reconfigure()

seek()

tell()

StringIO

getvalue()

IncrementalNewlineDecoder

성능

바이너리 I/O

텍스트 I/O

다중 스레드

재진입

time — Time access and conversions

함수

asctime()

pthread_getcpuclockid()

clock_getres()

clock_gettime()

clock_gettime_ns()

clock_settime()

clock_settime_ns()

ctime()

get_clock_info()

gmtime()

localtime()

mktime()

monotonic()

monotonic_ns()

perf_counter()

perf_counter_ns()

process_time()

process_time_ns()

sleep()

strftime()

strptime()

struct_time

tm_year

tm_mon

tm_mday

tm_hour

tm_min

tm_sec

tm_wday

tm_yday

tm_isdst

tm_zone

tm_gmtoff

time()

time_ns()

thread_time()

thread_time_ns()

tzset()

시계 ID 상수

CLOCK_BOOTTIME

CLOCK_HIGHRES

CLOCK_MONOTONIC

CLOCK_MONOTONIC_RAW

CLOCK_MONOTONIC_RAW_APPROX

CLOCK_PROCESS_CPUTIME_ID

CLOCK_PROF

CLOCK_TAI

CLOCK_THREAD_CPUTIME_ID

CLOCK_UPTIME

CLOCK_UPTIME_RAW

CLOCK_UPTIME_RAW_APPROX

CLOCK_REALTIME

시간대 상수

altzone

daylight

timezone

tzname

argparse — Parser for command-line options, arguments and subcommands

ArgumentParser 객체

ArgumentParser

prog

usage

description

epilog

parents

formatter_class

RawDescriptionHelpFormatter

RawTextHelpFormatter

ArgumentDefaultsHelpFormatter

MetavarTypeHelpFormatter

prefix_chars

fromfile_prefix_chars

argument_default

allow_abbrev

conflict_handler

add_help

exit_on_error

suggest_on_error

add_argument() 메서드

add_argument()

name or flags

action

BooleanOptionalAction

nargs

const

default

type

choices

required

help

metavar

dest

deprecated

Action 클래스

Action

__call__()

format_usage()

parse_args() 메서드

parse_args()

옵션값 문법

잘못된 인자

- 를 포함하는 인자들

인자 약어 (접두사 일치)

sys.argv 너머

Namespace 객체

Namespace

기타 유틸리티

부속 명령

add_subparsers()

FileType 객체

FileType

인자 그룹

add_argument_group()

상호 배제

add_mutually_exclusive_group()

파서 기본값

set_defaults()

get_default()

도움말 인쇄

print_usage()

print_help()

format_usage()

format_help()

부분 파싱

parse_known_args()

파일 파싱 사용자 정의

convert_arg_line_to_args()

종료 메서드

exit()

error()

혼합 파싱

parse_intermixed_args()

parse_known_intermixed_args()

Registering custom types or actions

register()

Exceptions

ArgumentError

ArgumentTypeError

Argparse 자습서

개념

기본

위치 인자 소개

옵션 인자 소개

짧은 옵션

위치 및 옵션 인자 결합하기

조금 더 발전시키기

Specifying ambiguous arguments

충돌하는 옵션들

How to translate the argparse output

Custom type converters

맺음말

Upgrading optparse code

logging — Logging facility for Python

Logger 객체

Logger

name

level

parent

propagate

handlers

disabled

setLevel()

isEnabledFor()

getEffectiveLevel()

getChild()

getChildren()

debug()

info()

warning()

error()

critical()

log()

exception()

addFilter()

removeFilter()

filter()

addHandler()

removeHandler()

findCaller()

handle()

makeRecord()

hasHandlers()

로깅 수준

NOTSET

DEBUG

INFO

WARNING

ERROR

CRITICAL

Handler 객체

Handler

__init__()

createLock()

acquire()

release()

setLevel()

setFormatter()

addFilter()

removeFilter()

filter()

flush()

close()

handle()

handleError()

format()

emit()

Formatter 객체

Formatter

format()

formatTime()

formatException()

formatStack()

BufferingFormatter

formatHeader()

formatFooter()

format()

Filter 객체

Filter

filter()

LogRecord 객체

LogRecord

getMessage()

LogRecord 어트리뷰트

LoggerAdapter 객체

LoggerAdapter

process()

manager

_log

스레드 안전성

모듈 수준 함수

getLogger()

getLoggerClass()

getLogRecordFactory()

debug()

info()

warning()

error()

critical()

exception()

log()

disable()

addLevelName()

getLevelNamesMapping()

getLevelName()

getHandlerByName()

getHandlerNames()

makeLogRecord()

basicConfig()

shutdown()

setLoggerClass()

setLogRecordFactory()

모듈 수준 어트리뷰트

lastResort

raiseExceptions

warnings 모듈과의 통합

captureWarnings()

logging.config — Logging configuration

구성 함수

dictConfig()

fileConfig()

listen()

stopListening()

Security considerations

구성 딕셔너리 스키마

딕셔너리 스키마 세부사항

증분 구성

객체 연결

사용자 정의 객체

Handler configuration order

외부 객체에 대한 액세스

내부 객체에 대한 액세스

임포트 결정과 사용자 정의 임포터

Configuring QueueHandler and QueueListener

구성 파일 형식

logging.handlers — Logging handlers

StreamHandler

StreamHandler

emit()

flush()

setStream()

terminator

FileHandler

FileHandler

close()

emit()

NullHandler

NullHandler

emit()

handle()

createLock()

WatchedFileHandler

WatchedFileHandler

reopenIfNeeded()

emit()

BaseRotatingHandler

BaseRotatingHandler

namer

rotator

rotation_filename()

rotate()

RotatingFileHandler

RotatingFileHandler

doRollover()

emit()

TimedRotatingFileHandler

TimedRotatingFileHandler

doRollover()

emit()

getFilesToDelete()

SocketHandler

SocketHandler

close()

emit()

handleError()

makeSocket()

makePickle()

send()

createSocket()

DatagramHandler

DatagramHandler

emit()

makeSocket()

send()

SysLogHandler

SysLogHandler

close()

createSocket()

emit()

encodePriority()

mapPriority()

NTEventLogHandler

NTEventLogHandler

close()

emit()

getEventCategory()

getEventType()

getMessageID()

SMTPHandler

SMTPHandler

emit()

getSubject()

MemoryHandler

BufferingHandler

emit()

flush()

shouldFlush()

MemoryHandler

close()

flush()

setTarget()

shouldFlush()

HTTPHandler

HTTPHandler

mapLogRecord()

emit()

QueueHandler

QueueHandler

emit()

prepare()

enqueue()

listener

QueueListener

QueueListener

dequeue()

prepare()

handle()

start()

stop()

enqueue_sentinel()

getpass — Portable password input

getpass()

GetPassWarning

getuser()

curses — Terminal handling for character-cell displays

함수

error

baudrate()

beep()

can_change_color()

cbreak()

color_content()

color_pair()

curs_set()

def_prog_mode()

def_shell_mode()

delay_output()

doupdate()

echo()

endwin()

erasechar()

filter()

flash()

flushinp()

getmouse()

getsyx()

getwin()

has_colors()

has_extended_color_support()

has_ic()

has_il()

has_key()

halfdelay()

init_color()

init_pair()

initscr()

is_term_resized()

isendwin()

keyname()

killchar()

longname()

meta()

mouseinterval()

mousemask()

napms()

newpad()

newwin()

nl()

nocbreak()

noecho()

nonl()

noqiflush()

noraw()

pair_content()

pair_number()

putp()

qiflush()

raw()

reset_prog_mode()

reset_shell_mode()

resetty()

resize_term()

resizeterm()

savetty()

get_escdelay()

set_escdelay()

get_tabsize()

set_tabsize()

setsyx()

setupterm()

start_color()

termattrs()

termname()

tigetflag()

tigetnum()

tigetstr()

tparm()

typeahead()

unctrl()

ungetch()

update_lines_cols()

unget_wch()

ungetmouse()

use_env()

use_default_colors()

wrapper()

창 객체

addch()

addnstr()

addstr()

attroff()

attron()

attrset()

bkgd()

bkgdset()

border()

box()

chgat()

clear()

clearok()

clrtobot()

clrtoeol()

cursyncup()

delch()

deleteln()

derwin()

echochar()

enclose()

encoding

erase()

getbegyx()

getbkgd()

getch()

get_wch()

getkey()

getmaxyx()

getparyx()

getstr()

getyx()

hline()

idcok()

idlok()

immedok()

inch()

insch()

insdelln()

insertln()

insnstr()

insstr()

instr()

is_linetouched()

is_wintouched()

keypad()

leaveok()

move()

mvderwin()

mvwin()

nodelay()

notimeout()

noutrefresh()

overlay()

overwrite()

putwin()

redrawln()

redrawwin()

refresh()

resize()

scroll()

scrollok()

setscrreg()

standend()

standout()

subpad()

subwin()

syncdown()

syncok()

syncup()

timeout()

touchline()

touchwin()

untouchwin()

vline()

상수

ERR

OK

version

__version__

ncurses_version

COLORS

COLOR_PAIRS

COLS

LINES

A_ALTCHARSET

A_BLINK

A_BOLD

A_DIM

A_INVIS

A_ITALIC

A_NORMAL

A_PROTECT

A_REVERSE

A_STANDOUT

A_UNDERLINE

A_HORIZONTAL

A_LEFT

A_LOW

A_RIGHT

A_TOP

A_VERTICAL

A_ATTRIBUTES

A_CHARTEXT

A_COLOR

KEY_MIN

KEY_BREAK

KEY_DOWN

KEY_UP

KEY_LEFT

KEY_RIGHT

KEY_HOME

KEY_BACKSPACE

KEY_F0

KEY_Fn

KEY_DL

KEY_IL

KEY_DC

KEY_IC

KEY_EIC

KEY_CLEAR

KEY_EOS

KEY_EOL

KEY_SF

KEY_SR

KEY_NPAGE

KEY_PPAGE

KEY_STAB

KEY_CTAB

KEY_CATAB

KEY_ENTER

KEY_SRESET

KEY_RESET

KEY_PRINT

KEY_LL

KEY_A1

KEY_A3

KEY_B2

KEY_C1

KEY_C3

KEY_BTAB

KEY_BEG

KEY_CANCEL

KEY_CLOSE

KEY_COMMAND

KEY_COPY

KEY_CREATE

KEY_END

KEY_EXIT

KEY_FIND

KEY_HELP

KEY_MARK

KEY_MESSAGE

KEY_MOVE

KEY_NEXT

KEY_OPEN

KEY_OPTIONS

KEY_PREVIOUS

KEY_REDO

KEY_REFERENCE

KEY_REFRESH

KEY_REPLACE

KEY_RESTART

KEY_RESUME

KEY_SAVE

KEY_SBEG

KEY_SCANCEL

KEY_SCOMMAND

KEY_SCOPY

KEY_SCREATE

KEY_SDC

KEY_SDL

KEY_SELECT

KEY_SEND

KEY_SEOL

KEY_SEXIT

KEY_SFIND

KEY_SHELP

KEY_SHOME

KEY_SIC

KEY_SLEFT

KEY_SMESSAGE

KEY_SMOVE

KEY_SNEXT

KEY_SOPTIONS

KEY_SPREVIOUS

KEY_SPRINT

KEY_SREDO

KEY_SREPLACE

KEY_SRIGHT

KEY_SRSUME

KEY_SSAVE

KEY_SSUSPEND

KEY_SUNDO

KEY_SUSPEND

KEY_UNDO

KEY_MOUSE

KEY_RESIZE

KEY_MAX

ACS_BBSS

ACS_BLOCK

ACS_BOARD

ACS_BSBS

ACS_BSSB

ACS_BSSS

ACS_BTEE

ACS_BULLET

ACS_CKBOARD

ACS_DARROW

ACS_DEGREE

ACS_DIAMOND

ACS_GEQUAL

ACS_HLINE

ACS_LANTERN

ACS_LARROW

ACS_LEQUAL

ACS_LLCORNER

ACS_LRCORNER

ACS_LTEE

ACS_NEQUAL

ACS_PI

ACS_PLMINUS

ACS_PLUS

ACS_RARROW

ACS_RTEE

ACS_S1

ACS_S3

ACS_S7

ACS_S9

ACS_SBBS

ACS_SBSB

ACS_SBSS

ACS_SSBB

ACS_SSBS

ACS_SSSB

ACS_SSSS

ACS_STERLING

ACS_TTEE

ACS_UARROW

ACS_ULCORNER

ACS_URCORNER

ACS_VLINE

BUTTONn_PRESSED

BUTTONn_RELEASED

BUTTONn_CLICKED

BUTTONn_DOUBLE_CLICKED

BUTTONn_TRIPLE_CLICKED

BUTTON_SHIFT

BUTTON_CTRL

BUTTON_ALT

COLOR_BLACK

COLOR_BLUE

COLOR_CYAN

COLOR_GREEN

COLOR_MAGENTA

COLOR_RED

COLOR_WHITE

COLOR_YELLOW

curses.textpad — curses 프로그램을 위한 텍스트 입력 위젯

rectangle()

Textbox 객체

Textbox

edit()

do_command()

gather()

stripspaces

curses.ascii — Utilities for ASCII characters

NUL

SOH

STX

ETX

EOT

ENQ

ACK

BEL

BS

TAB

HT

LF

NL

VT

FF

CR

SO

SI

DLE

DC1

DC2

DC3

DC4

NAK

SYN

ETB

CAN

EM

SUB

ESC

FS

GS

RS

US

SP

DEL

isalnum()

isalpha()

isascii()

isblank()

iscntrl()

isdigit()

isgraph()

islower()

isprint()

ispunct()

isspace()

isupper()

isxdigit()

isctrl()

ismeta()

ascii()

ctrl()

alt()

unctrl()

controlnames

curses.panel — A panel stack extension for curses

함수

bottom_panel()

new_panel()

top_panel()

update_panels()

Panel 객체

above()

below()

bottom()

hidden()

hide()

move()

replace()

set_userptr()

show()

top()

userptr()

window()

platform — Access to underlying platform’s identifying data

크로스 플랫폼

architecture()

machine()

node()

platform()

processor()

python_build()

python_compiler()

python_branch()

python_implementation()

python_revision()

python_version()

python_version_tuple()

release()

system()

system_alias()

version()

uname()

자바 플랫폼

java_ver()

윈도우 플랫폼

win32_ver()

win32_edition()

win32_is_iot()

macOS Platform

mac_ver()

iOS Platform

ios_ver()

유닉스 플랫폼

libc_ver()

Linux Platforms

freedesktop_os_release()

Android Platform

android_ver()

Miscellaneous

invalidate_caches()

errno — Standard errno system symbols

errorcode

EPERM

ENOENT

ESRCH

EINTR

EIO

ENXIO

E2BIG

ENOEXEC

EBADF

ECHILD

EAGAIN

ENOMEM

EACCES

EFAULT

ENOTBLK

EBUSY

EEXIST

EXDEV

ENODEV

ENOTDIR

EISDIR

EINVAL

ENFILE

EMFILE

ENOTTY

ETXTBSY

EFBIG

ENOSPC

ESPIPE

EROFS

EMLINK

EPIPE

EDOM

ERANGE

EDEADLK

ENAMETOOLONG

ENOLCK

ENOSYS

ENOTEMPTY

ELOOP

EWOULDBLOCK

ENOMSG

EIDRM

ECHRNG

EL2NSYNC

EL3HLT

EL3RST

ELNRNG

EUNATCH

ENOCSI

EL2HLT

EBADE

EBADR

EXFULL

ENOANO

EBADRQC

EBADSLT

EDEADLOCK

EBFONT

ENOSTR

ENODATA

ETIME

ENOSR

ENONET

ENOPKG

EREMOTE

ENOLINK

EADV

ESRMNT

ECOMM

EPROTO

EMULTIHOP

EDOTDOT

EBADMSG

EOVERFLOW

ENOTUNIQ

EBADFD

EREMCHG

ELIBACC

ELIBBAD

ELIBSCN

ELIBMAX

ELIBEXEC

EILSEQ

ERESTART

ESTRPIPE

EUSERS

ENOTSOCK

EDESTADDRREQ

EMSGSIZE

EPROTOTYPE

ENOPROTOOPT

EPROTONOSUPPORT

ESOCKTNOSUPPORT

EOPNOTSUPP

ENOTSUP

EPFNOSUPPORT

EAFNOSUPPORT

EADDRINUSE

EADDRNOTAVAIL

ENETDOWN

ENETUNREACH

ENETRESET

ECONNABORTED

ECONNRESET

ENOBUFS

EISCONN

ENOTCONN

ESHUTDOWN

ETOOMANYREFS

ETIMEDOUT

ECONNREFUSED

EHOSTDOWN

EHOSTUNREACH

EALREADY

EINPROGRESS

ESTALE

EUCLEAN

ENOTNAM

ENAVAIL

EISNAM

EREMOTEIO

EDQUOT

EQFULL

ENOTCAPABLE

ECANCELED

EOWNERDEAD

ENOTRECOVERABLE

ctypes — A foreign function library for Python

ctypes 자습서

동적 링크 라이브러리 로드하기

로드된 dll에서 함수에 액세스하기

함수 호출하기

기본 데이터형

함수 호출하기, 계속

Calling variadic functions

사용자 정의 데이터형을 사용하여 함수 호출하기

필수 인자 형 (함수 프로토타입) 지정하기

반환형

포인터 전달하기 (또는: 참조로 매개 변수 전달하기)

구조체와 공용체

Structure/union layout, alignment and byte order

구조체와 공용체의 비트 필드

배열

포인터

형 변환

불완전한 형

콜백 함수

dll에서 내 보낸 값을 액세스하기

의외의 것들

가변 크기 데이터형

ctypes 레퍼런스

공유 라이브러리 찾기

공유 라이브러리 로드하기

CDLL

OleDLL

WinDLL

PyDLL

_handle

_name

LibraryLoader

LoadLibrary()

외부 함수

_CFuncPtr

restype

argtypes

errcheck

함수 프로토타입

CFUNCTYPE()

WINFUNCTYPE()

PYFUNCTYPE()

유틸리티 함수

addressof()

alignment()

byref()

cast()

create_string_buffer()

create_unicode_buffer()

DllCanUnloadNow()

DllGetClassObject()

find_library()

find_msvcrt()

FormatError()

GetLastError()

get_errno()

get_last_error()

memmove()

memset()

POINTER()

pointer()

resize()

set_errno()

set_last_error()

sizeof()

string_at()

WinError()

wstring_at()

데이터형

_CData

from_buffer()

from_buffer_copy()

from_address()

from_param()

in_dll()

_b_base_

_b_needsfree_

_objects

기본 데이터형

_SimpleCData

value

c_byte

c_char

c_char_p

c_double

c_longdouble

c_float

c_double_complex

c_float_complex

c_longdouble_complex

c_int

c_int8

c_int16

c_int32

c_int64

c_long

c_longlong

c_short

c_size_t

c_ssize_t

c_time_t

c_ubyte

c_uint

c_uint8

c_uint16

c_uint32

c_uint64

c_ulong

c_ulonglong

c_ushort

c_void_p

c_wchar

c_wchar_p

c_bool

HRESULT

py_object

구조화된 데이터형

Union

BigEndianUnion

LittleEndianUnion

BigEndianStructure

LittleEndianStructure

Structure

_fields_

_pack_

_align_

_layout_

_anonymous_

배열과 포인터

Array

_length_

_type_

ARRAY()

_Pointer

_type_

contents

Exceptions

ArgumentError

COMError

hresult

text

details

동시 실행

threading — Thread-based parallelism

active_count()

current_thread()

excepthook()

__excepthook__

get_ident()

get_native_id()

enumerate()

main_thread()

settrace()

settrace_all_threads()

gettrace()

setprofile()

setprofile_all_threads()

getprofile()

stack_size()

TIMEOUT_MAX

스레드 로컬 데이터

local

Thread 객체

Thread

start()

run()

join()

name

getName()

setName()

ident

native_id

is_alive()

daemon

isDaemon()

setDaemon()

Lock 객체

Lock

acquire()

release()

locked()

RLock 객체

RLock

acquire()

release()

Condition 객체

Condition

acquire()

release()

wait()

wait_for()

notify()

notify_all()

Semaphore 객체

Semaphore

acquire()

release()

BoundedSemaphore

Semaphore 예

Event 객체

Event

is_set()

set()

clear()

wait()

Timer 객체

Timer

cancel()

Barrier 객체

Barrier

wait()

reset()

abort()

parties

n_waiting

broken

BrokenBarrierError

with 문으로 록, 조건 및 세마포어 사용하기

multiprocessing — Process-based parallelism

소개

Process 클래스

컨텍스트 및 시작 방법

프로세스 간 객체 교환

프로세스 간 동기화

프로세스 간 상태 공유

작업자 풀 사용

레퍼런스

Process와 예외

Process

run()

start()

join()

name

is_alive()

daemon

pid

exitcode

authkey

sentinel

terminate()

kill()

close()

ProcessError

BufferTooShort

AuthenticationError

TimeoutError

파이프와 큐

Pipe()

Queue

qsize()

empty()

full()

put()

put_nowait()

get()

get_nowait()

close()

join_thread()

cancel_join_thread()

SimpleQueue

close()

empty()

get()

put()

JoinableQueue

task_done()

join()

잡동사니

active_children()

cpu_count()

current_process()

parent_process()

freeze_support()

get_all_start_methods()

get_context()

get_start_method()

set_executable()

set_forkserver_preload()

set_start_method()

Connection 객체

Connection

send()

recv()

fileno()

close()

poll()

send_bytes()

recv_bytes()

recv_bytes_into()

동기화 프리미티브

Barrier

BoundedSemaphore

Condition

Event

Lock

acquire()

release()

RLock

acquire()

release()

Semaphore

공유 ctypes 객체

Value()

Array()

multiprocessing.sharedctypes 모듈

RawArray()

RawValue()

Array()

Value()

copy()

synchronized()

관리자

Manager()

BaseManager

start()

get_server()

connect()

shutdown()

register()

address

SyncManager

Barrier()

BoundedSemaphore()

Condition()

Event()

Lock()

Namespace()

Queue()

RLock()

Semaphore()

Array()

Value()

dict()

list()

Namespace

사용자 정의 관리자

원격 관리자 사용하기

프락시 객체

BaseProxy

_callmethod()

_getvalue()

__repr__()

__str__()

정리

프로세스 풀

Pool

apply()

apply_async()

map()

map_async()

imap()

imap_unordered()

starmap()

starmap_async()

close()

terminate()

join()

AsyncResult

get()

wait()

ready()

successful()

리스너와 클라이언트

deliver_challenge()

answer_challenge()

Client()

Listener

accept()

close()

address

last_accepted

wait()

주소 형식

인증 키

로깅

get_logger()

log_to_stderr()

multiprocessing.dummy 모듈

ThreadPool

프로그래밍 지침

모든 시작 방법

spawn 과 forkserver 시작 방법

예제

multiprocessing.shared_memory — Shared memory for direct access across processes

SharedMemory

close()

unlink()

buf

name

size

SharedMemoryManager

SharedMemory()

ShareableList()

ShareableList

count()

index()

format

shm

The concurrent package

concurrent.futures — Launching parallel tasks

Executor 객체

Executor

submit()

map()

shutdown()

ThreadPoolExecutor

ThreadPoolExecutor

ThreadPoolExecutor 예제

InterpreterPoolExecutor

InterpreterPoolExecutor

ProcessPoolExecutor

ProcessPoolExecutor

ProcessPoolExecutor 예제

Future 객체

Future

cancel()

cancelled()

running()

done()

result()

exception()

add_done_callback()

set_running_or_notify_cancel()

set_result()

set_exception()

모듈 함수

wait()

FIRST_COMPLETED

FIRST_EXCEPTION

ALL_COMPLETED

as_completed()

예외 클래스

CancelledError

TimeoutError

BrokenExecutor

InvalidStateError

BrokenThreadPool

BrokenInterpreterPool

ExecutionFailed

BrokenProcessPool

subprocess — Subprocess management

subprocess 모듈 사용하기

run()

CompletedProcess

args

returncode

stdout

stderr

check_returncode()

DEVNULL

PIPE

STDOUT

SubprocessError

TimeoutExpired

cmd

timeout

output

stdout

stderr

CalledProcessError

returncode

cmd

output

stdout

stderr

자주 사용되는 인자

Popen 생성자

Popen

예외

보안 고려 사항

Popen 객체

poll()

wait()

communicate()

send_signal()

terminate()

kill()

args

stdin

stdout

stderr

pid

returncode

윈도우 Popen 도우미

STARTUPINFO

dwFlags

hStdInput

hStdOutput

hStdError

wShowWindow

lpAttributeList

윈도우 상수

STD_INPUT_HANDLE

STD_OUTPUT_HANDLE

STD_ERROR_HANDLE

SW_HIDE

STARTF_USESTDHANDLES

STARTF_USESHOWWINDOW

STARTF_FORCEONFEEDBACK

STARTF_FORCEOFFFEEDBACK

CREATE_NEW_CONSOLE

CREATE_NEW_PROCESS_GROUP

ABOVE_NORMAL_PRIORITY_CLASS

BELOW_NORMAL_PRIORITY_CLASS

HIGH_PRIORITY_CLASS

IDLE_PRIORITY_CLASS

NORMAL_PRIORITY_CLASS

REALTIME_PRIORITY_CLASS

CREATE_NO_WINDOW

DETACHED_PROCESS

CREATE_DEFAULT_ERROR_MODE

CREATE_BREAKAWAY_FROM_JOB

오래된 고수준 API

call()

check_call()

check_output()

이전 함수를 subprocess 모듈로 교체하기

/bin/sh 셸 명령 치환 교체하기

셸 파이프라인 교체하기

os.system() 교체하기

os.spawn 패밀리 교체하기

Replacing os.popen()

레거시 셸 호출 함수

getstatusoutput()

getoutput()

노트

윈도우에서 인자 시퀀스를 문자열로 변환하기

Disable use of posix_spawn()

sched — Event scheduler

scheduler

스케줄러 객체

enterabs()

enter()

cancel()

empty()

run()

queue

queue — A synchronized queue class

Queue

LifoQueue

PriorityQueue

SimpleQueue

Empty

Full

ShutDown

큐 객체

qsize()

empty()

full()

put()

put_nowait()

get()

get_nowait()

task_done()

join()

Terminating queues

shutdown()

SimpleQueue 객체

qsize()

empty()

put()

put_nowait()

get()

get_nowait()

contextvars — Context Variables

컨텍스트 변수

ContextVar

name

get()

set()

reset()

Token

var

old_value

MISSING

수동 컨텍스트 관리

copy_context()

Context

run()

copy()

get()

keys()

values()

items()

asyncio 지원

_thread — Low-level threading API

error

LockType

start_new_thread()

interrupt_main()

exit()

allocate_lock()

get_ident()

get_native_id()

stack_size()

TIMEOUT_MAX

acquire()

release()

locked()

네트워킹과 프로세스 간 통신

asyncio — Asynchronous I/O

Runners

Running an asyncio Program

run()

Runner context manager

Runner

run()

close()

get_loop()

Handling Keyboard Interruption

코루틴과 태스크

코루틴

어웨이터블

태스크 만들기

create_task()

Task Cancellation

Task Groups

TaskGroup

create_task()

Terminating a Task Group

잠자기

sleep()

동시에 태스크 실행하기

gather()

Eager Task Factory

eager_task_factory()

create_eager_task_factory()

취소로부터 보호하기

shield()

시간제한

timeout()

Timeout

when()

reschedule()

expired()

timeout_at()

wait_for()

대기 프리미티브

wait()

FIRST_COMPLETED

FIRST_EXCEPTION

ALL_COMPLETED

as_completed()

스레드에서 실행하기

to_thread()

다른 스레드에서 예약하기

run_coroutine_threadsafe()

인트로스펙션

current_task()

all_tasks()

iscoroutine()

Task 객체

Task

done()

result()

exception()

add_done_callback()

remove_done_callback()

get_stack()

print_stack()

get_coro()

get_context()

get_name()

set_name()

cancel()

cancelled()

uncancel()

cancelling()

스트림

open_connection()

start_server()

open_unix_connection()

start_unix_server()

StreamReader

StreamReader

feed_eof()

read()

readline()

readexactly()

readuntil()

at_eof()

StreamWriter

StreamWriter

write()

writelines()

close()

can_write_eof()

write_eof()

transport

get_extra_info()

drain()

start_tls()

is_closing()

wait_closed()

예제

스트림을 사용하는 TCP 메아리 클라이언트

스트림을 사용하는 TCP 메아리 서버

HTTP 헤더 가져오기

스트림을 사용하여 데이터를 기다리는 열린 소켓 등록

동기화 프리미티브

Lock

Lock

acquire()

release()

locked()

Event

Event

wait()

set()

clear()

is_set()

Condition

Condition

acquire()

notify()

locked()

notify_all()

release()

wait()

wait_for()

Semaphore

Semaphore

acquire()

locked()

release()

BoundedSemaphore

BoundedSemaphore

Barrier

Barrier

wait()

reset()

abort()

parties

n_waiting

broken

BrokenBarrierError

서브 프로세스

서브 프로세스 만들기

create_subprocess_exec()

create_subprocess_shell()

상수

PIPE

STDOUT

DEVNULL

서브 프로세스와 상호 작용하기

Process

wait()

communicate()

send_signal()

terminate()

kill()

stdin

stdout

stderr

pid

returncode

서브 프로세스와 스레드

예제

큐

Queue

Queue

maxsize

empty()

full()

get()

get_nowait()

join()

put()

put_nowait()

qsize()

shutdown()

task_done()

우선순위 큐

PriorityQueue

LIFO 큐

LifoQueue

예외

QueueEmpty

QueueFull

QueueShutDown

예제

예외

TimeoutError

CancelledError

InvalidStateError

SendfileNotAvailableError

IncompleteReadError

expected

partial

LimitOverrunError

consumed

이벤트 루프

get_running_loop()

get_event_loop()

set_event_loop()

new_event_loop()

이벤트 루프 메서드

루프 실행 및 중지

run_until_complete()

run_forever()

stop()

is_running()

is_closed()

close()

shutdown_asyncgens()

shutdown_default_executor()

콜백 예약하기

call_soon()

call_soon_threadsafe()

지연된 콜백 예약

call_later()

call_at()

time()

퓨처와 태스크 만들기

create_future()

create_task()

set_task_factory()

get_task_factory()

네트워크 연결 열기

create_connection()

create_datagram_endpoint()

create_unix_connection()

네트워크 서버 만들기

create_server()

create_unix_server()

connect_accepted_socket()

파일 전송

sendfile()

TLS 업그레이드

start_tls()

파일 기술자 관찰하기

add_reader()

remove_reader()

add_writer()

remove_writer()

소켓 객체로 직접 작업하기

sock_recv()

sock_recv_into()

sock_recvfrom()

sock_recvfrom_into()

sock_sendall()

sock_sendto()

sock_connect()

sock_accept()

sock_sendfile()

DNS

getaddrinfo()

getnameinfo()

파이프로 작업하기

connect_read_pipe()

connect_write_pipe()

유닉스 시그널

add_signal_handler()

remove_signal_handler()

스레드 또는 프로세스 풀에서 코드를 실행하기

run_in_executor()

set_default_executor()

에러 처리 API

set_exception_handler()

get_exception_handler()

default_exception_handler()

call_exception_handler()

디버그 모드 활성화

get_debug()

set_debug()

slow_callback_duration

자식 프로세스 실행하기

subprocess_exec()

subprocess_shell()

콜백 핸들

Handle

get_context()

cancel()

cancelled()

TimerHandle

when()

서버 객체

Server

close()

close_clients()

abort_clients()

get_loop()

start_serving()

serve_forever()

is_serving()

wait_closed()

sockets

이벤트 루프 구현

SelectorEventLoop

ProactorEventLoop

EventLoop

AbstractEventLoop

예제

call_soon()을 사용하는 Hello World

call_later()로 현재 날짜를 표시합니다.

파일 기술자에서 읽기 이벤트를 관찰하기

SIGINT 및 SIGTERM에 대한 시그널 처리기 설정

퓨처

퓨처 함수

isfuture()

ensure_future()

wrap_future()

Future 객체

Future

result()

set_result()

set_exception()

done()

cancelled()

add_done_callback()

remove_done_callback()

cancel()

exception()

get_loop()

트랜스포트와 프로토콜

트랜스포트

트랜스포트 계층 구조

BaseTransport

WriteTransport

ReadTransport

Transport

DatagramTransport

SubprocessTransport

베이스 트랜스포트

close()

is_closing()

get_extra_info()

set_protocol()

get_protocol()

읽기 전용 트랜스포트

is_reading()

pause_reading()

resume_reading()

쓰기 전용 트랜스포트

abort()

can_write_eof()

get_write_buffer_size()

get_write_buffer_limits()

set_write_buffer_limits()

write()

writelines()

write_eof()

데이터 그램 트랜스포트

sendto()

abort()

서브 프로세스 트랜스포트

get_pid()

get_pipe_transport()

get_returncode()

kill()

send_signal()

terminate()

close()

프로토콜

베이스 프로토콜

BaseProtocol

Protocol

BufferedProtocol

DatagramProtocol

SubprocessProtocol

베이스 프로토콜

connection_made()

connection_lost()

pause_writing()

resume_writing()

스트리밍 프로토콜

data_received()

eof_received()

버퍼 된 스트리밍 프로토콜

get_buffer()

buffer_updated()

eof_received()

데이터 그램 프로토콜

datagram_received()

error_received()

서브 프로세스 프로토콜

pipe_data_received()

pipe_connection_lost()

process_exited()

예제

TCP 메아리 서버

TCP 메아리 클라이언트

UDP 메아리 서버

UDP 메아리 클라이언트

기존 소켓 연결하기

loop.subprocess_exec() 와 SubprocessProtocol

정책

정책을 얻고 설정하기

get_event_loop_policy()

set_event_loop_policy()

정책 객체

AbstractEventLoopPolicy

get_event_loop()

set_event_loop()

new_event_loop()

DefaultEventLoopPolicy

WindowsSelectorEventLoopPolicy

WindowsProactorEventLoopPolicy

사용자 정의 정책

플랫폼 지원

모든 플랫폼

윈도우

윈도우에서의 서브 프로세스 지원

macOS

Extending

Writing a Custom Event Loop

Future and Task private constructors

__init__()

__init__()

Task lifetime support

_register_task()

_unregister_task()

_enter_task()

_leave_task()

고수준 API 색인

태스크

큐

서브 프로세스

스트림

동기화

예외

저수준 API 색인

이벤트 루프 얻기

이벤트 루프 메서드

트랜스포트

프로토콜

이벤트 루프 정책

asyncio로 개발하기

디버그 모드

동시성과 다중 스레드

블로킹 코드 실행하기

로깅

await 하지 않은 코루틴 감지

전달되지 않은 예외 감지

socket — Low-level networking interface

소켓 패밀리

모듈 내용

예외

error

herror

gaierror

timeout

상수

AF_UNIX

AF_INET

AF_INET6

AF_UNSPEC

SOCK_STREAM

SOCK_DGRAM

SOCK_RAW

SOCK_RDM

SOCK_SEQPACKET

SOCK_CLOEXEC

SOCK_NONBLOCK

SOMAXCONN

AF_CAN

PF_CAN

CAN_BCM

CAN_RAW_FD_FRAMES

CAN_RAW_JOIN_FILTERS

CAN_ISOTP

CAN_J1939

AF_DIVERT

PF_DIVERT

AF_PACKET

PF_PACKET

ETH_P_ALL

AF_RDS

PF_RDS

SOL_RDS

SIO_RCVALL

SIO_KEEPALIVE_VALS

SIO_LOOPBACK_FAST_PATH

AF_ALG

SOL_ALG

AF_VSOCK

IOCTL_VM_SOCKETS_GET_LOCAL_CID

AF_LINK

has_ipv6

BDADDR_ANY

BDADDR_LOCAL

HCI_FILTER

HCI_TIME_STAMP

HCI_DATA_DIR

AF_QIPCRTR

SCM_CREDS2

LOCAL_CREDS

LOCAL_CREDS_PERSISTENT

SO_INCOMING_CPU

AF_HYPERV

HV_PROTOCOL_RAW

HVSOCKET_CONNECT_TIMEOUT

HVSOCKET_CONNECT_TIMEOUT_MAX

HVSOCKET_CONNECTED_SUSPEND

HVSOCKET_ADDRESS_FLAG_PASSTHRU

HV_GUID_ZERO

HV_GUID_WILDCARD

HV_GUID_BROADCAST

HV_GUID_CHILDREN

HV_GUID_LOOPBACK

HV_GUID_PARENT

ETHERTYPE_ARP

ETHERTYPE_IP

ETHERTYPE_IPV6

ETHERTYPE_VLAN

SHUT_RD

SHUT_WR

SHUT_RDWR

함수

소켓 만들기

socket

socketpair()

create_connection()

create_server()

has_dualstack_ipv6()

fromfd()

fromshare()

SocketType

기타 함수

close()

getaddrinfo()

getfqdn()

gethostbyname()

gethostbyname_ex()

gethostname()

gethostbyaddr()

getnameinfo()

getprotobyname()

getservbyname()

getservbyport()

ntohl()

ntohs()

htonl()

htons()

inet_aton()

inet_ntoa()

inet_pton()

inet_ntop()

CMSG_LEN()

CMSG_SPACE()

getdefaulttimeout()

setdefaulttimeout()

sethostname()

if_nameindex()

if_nametoindex()

if_indextoname()

send_fds()

recv_fds()

소켓 객체

accept()

bind()

close()

connect()

connect_ex()

detach()

dup()

fileno()

get_inheritable()

getpeername()

getsockname()

getsockopt()

getblocking()

gettimeout()

ioctl()

listen()

makefile()

recv()

recvfrom()

recvmsg()

recvmsg_into()

recvfrom_into()

recv_into()

send()

sendall()

sendto()

sendmsg()

sendmsg_afalg()

sendfile()

set_inheritable()

setblocking()

settimeout()

setsockopt()

shutdown()

share()

family

type

proto

소켓 시간제한에 대한 참고 사항

시간제한과 connect 메서드

시간제한과 accept 메서드

예제

ssl — TLS/SSL wrapper for socket objects

함수, 상수 및 예외

소켓 생성

컨텍스트 생성

create_default_context()

예외

SSLError

library

reason

SSLZeroReturnError

SSLWantReadError

SSLWantWriteError

SSLSyscallError

SSLEOFError

SSLCertVerificationError

verify_code

verify_message

CertificateError

난수 생성

RAND_bytes()

RAND_status()

RAND_add()

인증서 처리

cert_time_to_seconds()

get_server_certificate()

DER_cert_to_PEM_cert()

PEM_cert_to_DER_cert()

get_default_verify_paths()

enum_certificates()

enum_crls()

상수

CERT_NONE

CERT_OPTIONAL

CERT_REQUIRED

VerifyMode

VERIFY_DEFAULT

VERIFY_CRL_CHECK_LEAF

VERIFY_CRL_CHECK_CHAIN

VERIFY_X509_STRICT

VERIFY_ALLOW_PROXY_CERTS

VERIFY_X509_TRUSTED_FIRST

VERIFY_X509_PARTIAL_CHAIN

VerifyFlags

PROTOCOL_TLS

PROTOCOL_TLS_CLIENT

PROTOCOL_TLS_SERVER

PROTOCOL_SSLv23

PROTOCOL_SSLv3

PROTOCOL_TLSv1

PROTOCOL_TLSv1_1

PROTOCOL_TLSv1_2

OP_ALL

OP_NO_SSLv2

OP_NO_SSLv3

OP_NO_TLSv1

OP_NO_TLSv1_1

OP_NO_TLSv1_2

OP_NO_TLSv1_3

OP_NO_RENEGOTIATION

OP_CIPHER_SERVER_PREFERENCE

OP_SINGLE_DH_USE

OP_SINGLE_ECDH_USE

OP_ENABLE_MIDDLEBOX_COMPAT

OP_NO_COMPRESSION

Options

OP_NO_TICKET

OP_IGNORE_UNEXPECTED_EOF

OP_ENABLE_KTLS

OP_LEGACY_SERVER_CONNECT

HAS_ALPN

HAS_NEVER_CHECK_COMMON_NAME

HAS_ECDH

HAS_SNI

HAS_NPN

HAS_SSLv2

HAS_SSLv3

HAS_TLSv1

HAS_TLSv1_1

HAS_TLSv1_2

HAS_TLSv1_3

HAS_PSK

CHANNEL_BINDING_TYPES

OPENSSL_VERSION

OPENSSL_VERSION_INFO

OPENSSL_VERSION_NUMBER

ALERT_DESCRIPTION_HANDSHAKE_FAILURE

ALERT_DESCRIPTION_INTERNAL_ERROR

AlertDescription

SERVER_AUTH

CLIENT_AUTH

SSLErrorNumber

TLSVersion

MINIMUM_SUPPORTED

MAXIMUM_SUPPORTED

SSLv3

TLSv1

TLSv1_1

TLSv1_2

TLSv1_3

SSL 소켓

SSLSocket

read()

write()

do_handshake()

getpeercert()

get_verified_chain()

get_unverified_chain()

cipher()

shared_ciphers()

compression()

get_channel_binding()

selected_alpn_protocol()

selected_npn_protocol()

unwrap()

verify_client_post_handshake()

version()

pending()

context

server_side

server_hostname

session

session_reused

SSL 컨텍스트

SSLContext

cert_store_stats()

load_cert_chain()

load_default_certs()

load_verify_locations()

get_ca_certs()

get_ciphers()

set_default_verify_paths()

set_ciphers()

set_alpn_protocols()

set_npn_protocols()

sni_callback

set_servername_callback

load_dh_params()

set_ecdh_curve()

wrap_socket()

sslsocket_class

wrap_bio()

sslobject_class

session_stats()

check_hostname

keylog_filename

maximum_version

minimum_version

num_tickets

options

post_handshake_auth

protocol

hostname_checks_common_name

security_level

verify_flags

verify_mode

set_psk_client_callback()

set_psk_server_callback()

인증서

인증서 체인

CA 인증서

결합한 키와 인증서

자체 서명 인증서

예제

SSL 지원 검사하기

클라이언트 측 연산

서버 측 연산

비 블로킹 소켓에 대한 참고 사항

메모리 BIO 지원

SSLObject

MemoryBIO

pending

eof

read()

write()

write_eof()

SSL 세션

SSLSession

id

time

timeout

ticket_lifetime_hint

has_ticket

보안 고려 사항

가장 좋은 기본값

수동 설정

인증서 확인

프로토콜 버전

사이퍼 선택

다중 프로세싱

TLS 1.3

select — Waiting for I/O completion

error

devpoll()

epoll()

poll()

kqueue()

kevent()

select()

PIPE_BUF

/dev/poll 폴링 객체

close()

closed

fileno()

register()

modify()

unregister()

poll()

에지와 레벨 트리거 폴링 (epoll) 객체

close()

closed

fileno()

fromfd()

register()

modify()

unregister()

poll()

폴링 객체

register()

modify()

unregister()

poll()

Kqueue 객체

close()

closed

fileno()

fromfd()

control()

Kevent 객체

ident

filter

flags

fflags

data

udata

selectors — High-level I/O multiplexing

소개

클래스

EVENT_READ

EVENT_WRITE

SelectorKey

fileobj

fd

events

data

BaseSelector

register()

unregister()

modify()

select()

close()

get_key()

get_map()

DefaultSelector

SelectSelector

PollSelector

EpollSelector

fileno()

DevpollSelector

fileno()

KqueueSelector

fileno()

예제

signal — Set handlers for asynchronous events

일반 규칙

파이썬 시그널 처리기의 실행

시그널과 스레드

모듈 내용

Signals

Handlers

Sigmasks

SIG_DFL

SIG_IGN

SIGABRT

SIGALRM

SIGBREAK

SIGBUS

SIGCHLD

SIGCLD

SIGCONT

SIGFPE

SIGHUP

SIGILL

SIGINT

SIGKILL

SIGPIPE

SIGSEGV

SIGSTKFLT

SIGTERM

SIGUSR1

SIGUSR2

SIGWINCH

CTRL_C_EVENT

CTRL_BREAK_EVENT

NSIG

ITIMER_REAL

ITIMER_VIRTUAL

ITIMER_PROF

SIG_BLOCK

SIG_UNBLOCK

SIG_SETMASK

ItimerError

alarm()

getsignal()

strsignal()

valid_signals()

pause()

raise_signal()

pidfd_send_signal()

pthread_kill()

pthread_sigmask()

setitimer()

getitimer()

set_wakeup_fd()

siginterrupt()

signal()

sigpending()

sigwait()

sigwaitinfo()

sigtimedwait()

Examples

SIGPIPE에 대한 참고 사항

Note on Signal Handlers and Exceptions

mmap — Memory-mapped file support

mmap

close()

closed

find()

flush()

madvise()

move()

read()

read_byte()

readline()

resize()

rfind()

seek()

seekable()

size()

tell()

write()

write_byte()

MADV_* 상수

MADV_NORMAL

MADV_RANDOM

MADV_SEQUENTIAL

MADV_WILLNEED

MADV_DONTNEED

MADV_REMOVE

MADV_DONTFORK

MADV_DOFORK

MADV_HWPOISON

MADV_MERGEABLE

MADV_UNMERGEABLE

MADV_SOFT_OFFLINE

MADV_HUGEPAGE

MADV_NOHUGEPAGE

MADV_DONTDUMP

MADV_DODUMP

MADV_FREE

MADV_NOSYNC

MADV_AUTOSYNC

MADV_NOCORE

MADV_CORE

MADV_PROTECT

MADV_FREE_REUSABLE

MADV_FREE_REUSE

MAP_* Constants

MAP_SHARED

MAP_PRIVATE

MAP_32BIT

MAP_ALIGNED_SUPER

MAP_ANON

MAP_ANONYMOUS

MAP_CONCEAL

MAP_DENYWRITE

MAP_EXECUTABLE

MAP_HASSEMAPHORE

MAP_JIT

MAP_NOCACHE

MAP_NOEXTEND

MAP_NORESERVE

MAP_POPULATE

MAP_RESILIENT_CODESIGN

MAP_RESILIENT_MEDIA

MAP_STACK

MAP_TPRO

MAP_TRANSLATED_ALLOW_EXECUTE

MAP_UNIX03

인터넷 데이터 처리

email — An email and MIME handling package

email.message: Representing an email message

EmailMessage

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

set_param()

del_param()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

is_attachment()

get_content_disposition()

walk()

get_body()

iter_attachments()

iter_parts()

get_content()

set_content()

make_related()

make_alternative()

make_mixed()

add_related()

add_alternative()

add_attachment()

clear()

clear_content()

preamble

epilogue

defects

MIMEPart

email.parser: Parsing email messages

FeedParser API

BytesFeedParser

feed()

close()

FeedParser

Parser API

BytesParser

parse()

parsebytes()

BytesHeaderParser

Parser

parse()

parsestr()

HeaderParser

message_from_bytes()

message_from_binary_file()

message_from_string()

message_from_file()

추가 사항

email.generator: Generating MIME documents

BytesGenerator

flatten()

clone()

write()

Generator

flatten()

clone()

write()

DecodedGenerator

email.policy: Policy Objects

Policy

max_line_length

linesep

cte_type

raise_on_defect

mangle_from_

message_factory

verify_generated_headers

clone()

handle_defect()

register_defect()

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

EmailPolicy

utf8

refold_source

header_factory

content_manager

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

default

SMTP

SMTPUTF8

HTTP

strict

Compat32

mangle_from_

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

compat32

email.errors: Exception and Defect classes

MessageError

MessageParseError

HeaderParseError

BoundaryError

MultipartConversionError

HeaderWriteError

MessageDefect

HeaderDefect

email.headerregistry: Custom Header Objects

BaseHeader

name

defects

max_count

fold()

UnstructuredHeader

DateHeader

datetime

AddressHeader

groups

addresses

SingleAddressHeader

address

MIMEVersionHeader

version

major

minor

ParameterizedMIMEHeader

params

ContentTypeHeader

content_type

maintype

subtype

ContentDispositionHeader

content_disposition

ContentTransferEncoding

cte

HeaderRegistry

map_to_type()

__getitem__()

__call__()

Address

display_name

username

domain

addr_spec

__str__()

Group

display_name

addresses

__str__()

email.contentmanager: Managing MIME Content

ContentManager

get_content()

set_content()

add_get_handler()

add_set_handler()

콘텐츠 관리자 인스턴스

raw_data_manager

get_content()

set_content()

email: 예제

email.message.Message: compat32 API를 사용하여 이메일 메시지 표현하기

Message

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

attach()

get_payload()

set_payload()

set_charset()

get_charset()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

get_params()

get_param()

set_param()

del_param()

set_type()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

get_content_disposition()

walk()

preamble

epilogue

defects

email.mime: Creating email and MIME objects from scratch

MIMEBase

MIMENonMultipart

MIMEMultipart

MIMEApplication

MIMEAudio

MIMEImage

MIMEMessage

MIMEText

email.header: Internationalized headers

Header

append()

encode()

__str__()

__eq__()

__ne__()

decode_header()

make_header()

email.charset: Representing character sets

Charset

input_charset

header_encoding

body_encoding

output_charset

input_codec

output_codec

get_body_encoding()

get_output_charset()

header_encode()

header_encode_lines()

body_encode()

__str__()

__eq__()

__ne__()

add_charset()

add_alias()

add_codec()

email.encoders: Encoders

encode_quopri()

encode_base64()

encode_7or8bit()

encode_noop()

email.utils: Miscellaneous utilities

localtime()

make_msgid()

quote()

unquote()

parseaddr()

formataddr()

getaddresses()

parsedate()

parsedate_tz()

parsedate_to_datetime()

mktime_tz()

formatdate()

format_datetime()

decode_rfc2231()

encode_rfc2231()

collapse_rfc2231_value()

decode_params()

email.iterators: Iterators

body_line_iterator()

typed_subpart_iterator()

_structure()

json — JSON encoder and decoder

기본 사용법

dump()

dumps()

load()

loads()

인코더와 디코더

JSONDecoder

decode()

raw_decode()

JSONEncoder

default()

encode()

iterencode()

예외

JSONDecodeError

msg

doc

pos

lineno

colno

표준 준수와 상호 운용성

문자 인코딩

무한대와 NaN 숫자 값

오브젝트 내에서 반복된 이름

오브젝트나 배열이 아닌 최상윗값

구현 제약 사항

Command-line interface

Command-line options

mailbox — Manipulate mailboxes in various formats

Mailbox objects

Mailbox

add()

remove()

__delitem__()

discard()

__setitem__()

iterkeys()

keys()

itervalues()

__iter__()

values()

iteritems()

items()

get()

__getitem__()

get_message()

get_bytes()

get_string()

get_file()

__contains__()

__len__()

clear()

pop()

popitem()

update()

flush()

lock()

unlock()

close()

Maildir objects

Maildir

colon

list_folders()

get_folder()

add_folder()

remove_folder()

clean()

get_flags()

set_flags()

add_flag()

remove_flag()

get_info()

set_info()

add()

__setitem__()

update()

flush()

lock()

unlock()

close()

get_file()

mbox objects

mbox

get_file()

lock()

unlock()

MH objects

MH

list_folders()

get_folder()

add_folder()

remove_folder()

get_sequences()

set_sequences()

pack()

remove()

__delitem__()

discard()

lock()

unlock()

get_file()

flush()

close()

Babyl objects

Babyl

get_labels()

get_file()

lock()

unlock()

MMDF objects

MMDF

get_file()

lock()

unlock()

Message objects

Message

MaildirMessage objects

MaildirMessage

get_subdir()

set_subdir()

get_flags()

set_flags()

add_flag()

remove_flag()

get_date()

set_date()

get_info()

set_info()

mboxMessage objects

mboxMessage

get_from()

set_from()

get_flags()

set_flags()

add_flag()

remove_flag()

MHMessage objects

MHMessage

get_sequences()

set_sequences()

add_sequence()

remove_sequence()

BabylMessage objects

BabylMessage

get_labels()

set_labels()

add_label()

remove_label()

get_visible()

set_visible()

update_visible()

MMDFMessage objects

MMDFMessage

get_from()

set_from()

get_flags()

set_flags()

add_flag()

remove_flag()

예외

Error

NoSuchMailboxError

NotEmptyError

ExternalClashError

FormatError

예

mimetypes — Map filenames to MIME types

guess_type()

guess_file_type()

guess_all_extensions()

guess_extension()

init()

read_mime_types()

add_type()

inited

knownfiles

suffix_map

encodings_map

types_map

common_types

MimeTypes 객체

MimeTypes

suffix_map

encodings_map

types_map

types_map_inv

guess_extension()

guess_type()

guess_file_type()

guess_all_extensions()

read()

readfp()

read_windows_registry()

add_type()

base64 — Base16, Base32, Base64, Base85 Data Encodings

b64encode()

b64decode()

standard_b64encode()

standard_b64decode()

urlsafe_b64encode()

urlsafe_b64decode()

b32encode()

b32decode()

b32hexencode()

b32hexdecode()

b16encode()

b16decode()

a85encode()

a85decode()

b85encode()

b85decode()

z85encode()

z85decode()

decode()

decodebytes()

encode()

encodebytes()

Security Considerations

binascii — Convert between binary and ASCII

a2b_uu()

b2a_uu()

a2b_base64()

b2a_base64()

a2b_qp()

b2a_qp()

crc_hqx()

crc32()

b2a_hex()

hexlify()

a2b_hex()

unhexlify()

Error

Incomplete

quopri — Encode and decode MIME quoted-printable data

decode()

encode()

decodestring()

encodestring()

구조화된 마크업 처리 도구

html — HyperText Markup Language support

escape()

unescape()

html.parser — Simple HTML and XHTML parser

HTMLParser

HTML 구문 분석기 응용 프로그램 예제

HTMLParser 메서드

feed()

close()

reset()

getpos()

get_starttag_text()

handle_starttag()

handle_endtag()

handle_startendtag()

handle_data()

handle_entityref()

handle_charref()

handle_comment()

handle_decl()

handle_pi()

unknown_decl()

예제

html.entities — Definitions of HTML general entities

html5

entitydefs

name2codepoint

codepoint2name

XML 처리 모듈

XML 취약점

The defusedxml Package

xml.etree.ElementTree — The ElementTree XML API

자습서

XML 트리와 엘리먼트

XML 구문 분석하기

비 블로킹 구문 분석을 위한 풀(pull) API

흥미로운 엘리먼트 찾기

XML 파일 수정하기

XML 문서 구축하기

이름 공간이 있는 XML 구문 분석하기

XPath 지원

예

지원되는 XPath 문법

레퍼런스

함수

canonicalize()

Comment()

dump()

fromstring()

fromstringlist()

indent()

iselement()

iterparse()

parse()

ProcessingInstruction()

register_namespace()

SubElement()

tostring()

tostringlist()

XML()

XMLID()

XInclude 지원

예

레퍼런스

함수

default_loader()

include()

Element 객체

Element

tag

text

tail

attrib

clear()

get()

items()

keys()

set()

append()

extend()

find()

findall()

findtext()

insert()

iter()

iterfind()

itertext()

makeelement()

remove()

ElementTree 객체

ElementTree

_setroot()

find()

findall()

findtext()

getroot()

iter()

iterfind()

parse()

write()

QName 객체

QName

TreeBuilder 객체

TreeBuilder

close()

data()

end()

start()

comment()

pi()

doctype()

start_ns()

end_ns()

C14NWriterTarget

XMLParser 객체

XMLParser

close()

feed()

flush()

XMLPullParser 객체

XMLPullParser

feed()

flush()

close()

read_events()

예외

ParseError

code

position

xml.dom — The Document Object Model API

모듈 내용

registerDOMImplementation()

getDOMImplementation()

EMPTY_NAMESPACE

XML_NAMESPACE

XMLNS_NAMESPACE

XHTML_NAMESPACE

DOM의 객체

DOMImplementation 객체

hasFeature()

createDocument()

createDocumentType()

Node 객체

nodeType

parentNode

attributes

previousSibling

nextSibling

childNodes

firstChild

lastChild

localName

prefix

namespaceURI

nodeName

nodeValue

hasAttributes()

hasChildNodes()

isSameNode()

appendChild()

insertBefore()

removeChild()

replaceChild()

normalize()

cloneNode()

NodeList 객체

item()

length

DocumentType 객체

publicId

systemId

internalSubset

name

entities

notations

Document 객체

documentElement

createElement()

createElementNS()

createTextNode()

createComment()

createProcessingInstruction()

createAttribute()

createAttributeNS()

getElementsByTagName()

getElementsByTagNameNS()

Element 객체

tagName

getElementsByTagName()

getElementsByTagNameNS()

hasAttribute()

hasAttributeNS()

getAttribute()

getAttributeNode()

getAttributeNS()

getAttributeNodeNS()

removeAttribute()

removeAttributeNode()

removeAttributeNS()

setAttribute()

setAttributeNode()

setAttributeNodeNS()

setAttributeNS()

Attr 객체

name

localName

prefix

value

NamedNodeMap 객체

length

item()

Comment 객체

data

Text와 CDATASection 객체

data

ProcessingInstruction 객체

target

data

예외

DOMException

DomstringSizeErr

HierarchyRequestErr

IndexSizeErr

InuseAttributeErr

InvalidAccessErr

InvalidCharacterErr

InvalidModificationErr

InvalidStateErr

NamespaceErr

NotFoundErr

NotSupportedErr

NoDataAllowedErr

NoModificationAllowedErr

SyntaxErr

WrongDocumentErr

규격 준수

형 매핑

접근자 메서드

xml.dom.minidom — Minimal DOM implementation

parse()

parseString()

DOM 객체

unlink()

writexml()

toxml()

toprettyxml()

DOM 예제

minidom과 DOM 표준

xml.dom.pulldom — Support for building partial DOM trees

PullDom

SAX2DOM

parse()

parseString()

default_bufsize

DOMEventStream 객체

DOMEventStream

getEvent()

expandNode()

reset()

xml.sax — Support for SAX2 parsers

make_parser()

parse()

parseString()

SAXException

SAXParseException

SAXNotRecognizedException

SAXNotSupportedException

SAXException 객체

getMessage()

getException()

xml.sax.handler — Base classes for SAX handlers

ContentHandler

DTDHandler

EntityResolver

ErrorHandler

LexicalHandler

feature_namespaces

feature_namespace_prefixes

feature_string_interning

feature_validation

feature_external_ges

feature_external_pes

all_features

property_lexical_handler

property_declaration_handler

property_dom_node

property_xml_string

all_properties

ContentHandler 객체

setDocumentLocator()

startDocument()

endDocument()

startPrefixMapping()

endPrefixMapping()

startElement()

endElement()

startElementNS()

endElementNS()

characters()

ignorableWhitespace()

processingInstruction()

skippedEntity()

DTDHandler 객체

notationDecl()

unparsedEntityDecl()

EntityResolver 객체

resolveEntity()

ErrorHandler 객체

error()

fatalError()

warning()

LexicalHandler Objects

comment()

startDTD()

endDTD()

startCDATA()

endCDATA()

xml.sax.saxutils — SAX Utilities

escape()

unescape()

quoteattr()

XMLGenerator

XMLFilterBase

prepare_input_source()

xml.sax.xmlreader — Interface for XML parsers

XMLReader

IncrementalParser

Locator

InputSource

AttributesImpl

AttributesNSImpl

XMLReader 객체

parse()

getContentHandler()

setContentHandler()

getDTDHandler()

setDTDHandler()

getEntityResolver()

setEntityResolver()

getErrorHandler()

setErrorHandler()

setLocale()

getFeature()

setFeature()

getProperty()

setProperty()

IncrementalParser 객체

feed()

close()

reset()

Locator 객체

getColumnNumber()

getLineNumber()

getPublicId()

getSystemId()

InputSource 객체

setPublicId()

getPublicId()

setSystemId()

getSystemId()

setEncoding()

getEncoding()

setByteStream()

getByteStream()

setCharacterStream()

getCharacterStream()

Attributes 인터페이스

getLength()

getNames()

getType()

getValue()

AttributesNS 인터페이스

getValueByQName()

getNameByQName()

getQNameByName()

getQNames()

xml.parsers.expat — Fast XML parsing using Expat

ExpatError

error

XMLParserType

ErrorString()

ParserCreate()

XMLParser 객체

Parse()

ParseFile()

SetBase()

GetBase()

GetInputContext()

ExternalEntityParserCreate()

SetParamEntityParsing()

UseForeignDTD()

SetReparseDeferralEnabled()

GetReparseDeferralEnabled()

buffer_size

buffer_text

buffer_used

ordered_attributes

specified_attributes

ErrorByteIndex

ErrorCode

ErrorColumnNumber

ErrorLineNumber

CurrentByteIndex

CurrentColumnNumber

CurrentLineNumber

XmlDeclHandler()

StartDoctypeDeclHandler()

EndDoctypeDeclHandler()

ElementDeclHandler()

AttlistDeclHandler()

StartElementHandler()

EndElementHandler()

ProcessingInstructionHandler()

CharacterDataHandler()

UnparsedEntityDeclHandler()

EntityDeclHandler()

NotationDeclHandler()

StartNamespaceDeclHandler()

EndNamespaceDeclHandler()

CommentHandler()

StartCdataSectionHandler()

EndCdataSectionHandler()

DefaultHandler()

DefaultHandlerExpand()

NotStandaloneHandler()

ExternalEntityRefHandler()

ExpatError 예외

code

lineno

offset

예

콘텐츠 모델 기술

Expat 에러 상수

codes

messages

XML_ERROR_ASYNC_ENTITY

XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF

XML_ERROR_BAD_CHAR_REF

XML_ERROR_BINARY_ENTITY_REF

XML_ERROR_DUPLICATE_ATTRIBUTE

XML_ERROR_INCORRECT_ENCODING

XML_ERROR_INVALID_TOKEN

XML_ERROR_JUNK_AFTER_DOC_ELEMENT

XML_ERROR_MISPLACED_XML_PI

XML_ERROR_NO_ELEMENTS

XML_ERROR_NO_MEMORY

XML_ERROR_PARAM_ENTITY_REF

XML_ERROR_PARTIAL_CHAR

XML_ERROR_RECURSIVE_ENTITY_REF

XML_ERROR_SYNTAX

XML_ERROR_TAG_MISMATCH

XML_ERROR_UNCLOSED_TOKEN

XML_ERROR_UNDEFINED_ENTITY

XML_ERROR_UNKNOWN_ENCODING

XML_ERROR_UNCLOSED_CDATA_SECTION

XML_ERROR_EXTERNAL_ENTITY_HANDLING

XML_ERROR_NOT_STANDALONE

XML_ERROR_UNEXPECTED_STATE

XML_ERROR_ENTITY_DECLARED_IN_PE

XML_ERROR_FEATURE_REQUIRES_XML_DTD

XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING

XML_ERROR_UNBOUND_PREFIX

XML_ERROR_UNDECLARING_PREFIX

XML_ERROR_INCOMPLETE_PE

XML_ERROR_XML_DECL

XML_ERROR_TEXT_DECL

XML_ERROR_PUBLICID

XML_ERROR_SUSPENDED

XML_ERROR_NOT_SUSPENDED

XML_ERROR_ABORTED

XML_ERROR_FINISHED

XML_ERROR_SUSPEND_PE

XML_ERROR_RESERVED_PREFIX_XML

XML_ERROR_RESERVED_PREFIX_XMLNS

XML_ERROR_RESERVED_NAMESPACE_URI

XML_ERROR_INVALID_ARGUMENT

XML_ERROR_NO_BUFFER

XML_ERROR_AMPLIFICATION_LIMIT_BREACH

인터넷 프로토콜과 지원

webbrowser — Convenient web-browser controller

Error

open()

open_new()

open_new_tab()

get()

register()

브라우저 제어기 객체

name

open()

open_new()

open_new_tab()

wsgiref — WSGI Utilities and Reference Implementation

wsgiref.util – WSGI 환경 유틸리티

guess_scheme()

request_uri()

application_uri()

shift_path_info()

setup_testing_defaults()

is_hop_by_hop()

FileWrapper

wsgiref.headers – WSGI 응답 헤더 도구

Headers

get_all()

add_header()

wsgiref.simple_server – 간단한 WSGI HTTP 서버

make_server()

demo_app()

WSGIServer

set_app()

get_app()

WSGIRequestHandler

get_environ()

get_stderr()

handle()

wsgiref.validate — WSGI 적합성 검사기

validator()

wsgiref.handlers – 서버/게이트웨이 베이스 클래스

CGIHandler

IISCGIHandler

BaseCGIHandler

SimpleHandler

BaseHandler

run()

_write()

_flush()

get_stdin()

get_stderr()

add_cgi_vars()

wsgi_multithread

wsgi_multiprocess

wsgi_run_once

os_environ

server_software

get_scheme()

setup_environ()

log_exception()

traceback_limit

error_output()

error_status

error_headers

error_body

wsgi_file_wrapper

sendfile()

origin_server

http_version

read_environ()

wsgiref.types – WSGI types for static type checking

StartResponse

WSGIEnvironment

WSGIApplication

InputStream

ErrorStream

FileWrapper

예제

urllib — URL handling modules

urllib.request — Extensible library for opening URLs

urlopen()

install_opener()

build_opener()

pathname2url()

url2pathname()

getproxies()

Request

OpenerDirector

BaseHandler

HTTPDefaultErrorHandler

HTTPRedirectHandler

HTTPCookieProcessor

ProxyHandler

HTTPPasswordMgr

HTTPPasswordMgrWithDefaultRealm

HTTPPasswordMgrWithPriorAuth

AbstractBasicAuthHandler

HTTPBasicAuthHandler

ProxyBasicAuthHandler

AbstractDigestAuthHandler

HTTPDigestAuthHandler

ProxyDigestAuthHandler

HTTPHandler

HTTPSHandler

FileHandler

DataHandler

FTPHandler

CacheFTPHandler

UnknownHandler

HTTPErrorProcessor

Request 객체

full_url

type

host

origin_req_host

selector

data

unverifiable

method

get_method()

add_header()

add_unredirected_header()

has_header()

remove_header()

get_full_url()

set_proxy()

get_header()

header_items()

OpenerDirector 객체

add_handler()

open()

error()

BaseHandler 객체

add_parent()

close()

parent

default_open()

unknown_open()

http_error_default()

HTTPRedirectHandler 객체

redirect_request()

http_error_301()

http_error_302()

http_error_303()

http_error_307()

http_error_308()

HTTPCookieProcessor 객체

cookiejar

ProxyHandler 객체

HTTPPasswordMgr 객체

add_password()

find_user_password()

HTTPPasswordMgrWithPriorAuth 객체

add_password()

find_user_password()

update_authenticated()

is_authenticated()

AbstractBasicAuthHandler 객체

http_error_auth_reqed()

HTTPBasicAuthHandler 객체

http_error_401()

ProxyBasicAuthHandler 객체

http_error_407()

AbstractDigestAuthHandler 객체

http_error_auth_reqed()

HTTPDigestAuthHandler 객체

http_error_401()

ProxyDigestAuthHandler 객체

http_error_407()

HTTPHandler 객체

http_open()

HTTPSHandler 객체

https_open()

FileHandler 객체

file_open()

DataHandler 객체

data_open()

FTPHandler 객체

ftp_open()

CacheFTPHandler 객체

setTimeout()

setMaxConns()

UnknownHandler 객체

unknown_open()

HTTPErrorProcessor 객체

http_response()

https_response()

예

레거시 인터페이스

urlretrieve()

urlcleanup()

urllib.request 제약 사항

urllib.response — urllib가 사용하는 응답 클래스

addinfourl

url

headers

status

geturl()

info()

code

getcode()

urllib.parse — Parse URLs into components

URL 구문 분석

urlparse()

parse_qs()

parse_qsl()

urlunparse()

urlsplit()

urlunsplit()

urljoin()

urldefrag()

unwrap()

URL parsing security

ASCII로 인코딩된 바이트열 구문 분석

구조화된 구문 분석 결과

geturl()

DefragResult

ParseResult

SplitResult

DefragResultBytes

ParseResultBytes

SplitResultBytes

URL 인용

quote()

quote_plus()

quote_from_bytes()

unquote()

unquote_plus()

unquote_to_bytes()

urlencode()

urllib.error — Exception classes raised by urllib.request

URLError

reason

HTTPError

url

code

reason

headers

fp

ContentTooShortError

content

urllib.robotparser — Parser for robots.txt

RobotFileParser

set_url()

read()

parse()

can_fetch()

mtime()

modified()

crawl_delay()

request_rate()

site_maps()

http — HTTP modules

HTTPStatus

HTTP 상태 코드

HTTP status category

HTTPMethod

HTTP methods

http.client — HTTP protocol client

HTTPConnection

HTTPSConnection

HTTPResponse

parse_headers()

HTTPException

NotConnected

InvalidURL

UnknownProtocol

UnknownTransferEncoding

UnimplementedFileMode

IncompleteRead

ImproperConnectionState

CannotSendRequest

CannotSendHeader

ResponseNotReady

BadStatusLine

LineTooLong

RemoteDisconnected

HTTP_PORT

HTTPS_PORT

responses

HTTPConnection 객체

request()

getresponse()

set_debuglevel()

set_tunnel()

get_proxy_response_headers()

connect()

close()

blocksize

putrequest()

putheader()

endheaders()

send()

HTTPResponse 객체

read()

readinto()

getheader()

getheaders()

fileno()

msg

version

url

headers

status

reason

debuglevel

closed

geturl()

info()

getcode()

예

HTTPMessage 객체

HTTPMessage

ftplib — FTP protocol client

Reference

FTP objects

FTP

set_debuglevel()

connect()

getwelcome()

login()

abort()

sendcmd()

voidcmd()

retrbinary()

retrlines()

set_pasv()

storbinary()

storlines()

transfercmd()

ntransfercmd()

mlsd()

nlst()

dir()

rename()

delete()

cwd()

mkd()

pwd()

rmd()

size()

quit()

close()

FTP_TLS objects

FTP_TLS

ssl_version

auth()

ccc()

prot_p()

prot_c()

Module variables

error_reply

error_temp

error_perm

error_proto

all_errors

poplib — POP3 protocol client

POP3

POP3_SSL

error_proto

POP3 객체

set_debuglevel()

getwelcome()

capa()

user()

pass_()

apop()

rpop()

stat()

list()

retr()

dele()

rset()

noop()

quit()

top()

uidl()

utf8()

stls()

POP3 예제

imaplib — IMAP4 protocol client

IMAP4

error

abort

readonly

IMAP4_SSL

IMAP4_stream

Internaldate2tuple()

Int2AP()

ParseFlags()

Time2Internaldate()

IMAP4 객체

append()

authenticate()

check()

close()

copy()

create()

delete()

deleteacl()

enable()

expunge()

fetch()

getacl()

getannotation()

getquota()

getquotaroot()

list()

login()

login_cram_md5()

logout()

lsub()

myrights()

namespace()

noop()

open()

partial()

proxyauth()

read()

readline()

recent()

rename()

response()

search()

select()

send()

setacl()

setannotation()

setquota()

shutdown()

socket()

sort()

starttls()

status()

store()

subscribe()

thread()

uid()

unsubscribe()

unselect()

xatom()

PROTOCOL_VERSION

debug

utf8_enabled

IMAP4 예

smtplib — SMTP protocol client

SMTP

SMTP_SSL

LMTP

SMTPException

SMTPServerDisconnected

SMTPResponseException

SMTPSenderRefused

SMTPRecipientsRefused

SMTPDataError

SMTPConnectError

SMTPHeloError

SMTPNotSupportedError

SMTPAuthenticationError

SMTP 객체

set_debuglevel()

docmd()

connect()

helo()

ehlo()

ehlo_or_helo_if_needed()

has_extn()

verify()

login()

auth()

starttls()

sendmail()

send_message()

quit()

SMTP 예

uuid — UUID objects according to RFC 9562

SafeUUID

safe

unsafe

unknown

UUID

bytes

bytes_le

fields

time_low

time_mid

time_hi_version

clock_seq_hi_variant

clock_seq_low

node

time

clock_seq

hex

int

urn

variant

version

is_safe

getnode()

uuid1()

uuid3()

uuid4()

uuid5()

uuid8()

NAMESPACE_DNS

NAMESPACE_URL

NAMESPACE_OID

NAMESPACE_X500

RESERVED_NCS

RFC_4122

RESERVED_MICROSOFT

RESERVED_FUTURE

Command-Line Usage

예제

Command-Line Example

socketserver — A framework for network servers

TCPServer

UDPServer

UnixStreamServer

UnixDatagramServer

서버 생성 노트

ForkingMixIn

ThreadingMixIn

block_on_close

max_children

daemon_threads

ForkingTCPServer

ForkingUDPServer

ThreadingTCPServer

ThreadingUDPServer

ForkingUnixStreamServer

ForkingUnixDatagramServer

ThreadingUnixStreamServer

ThreadingUnixDatagramServer

서버 객체

BaseServer

fileno()

handle_request()

serve_forever()

service_actions()

shutdown()

server_close()

address_family

RequestHandlerClass

server_address

socket

allow_reuse_address

request_queue_size

socket_type

timeout

finish_request()

get_request()

handle_error()

handle_timeout()

process_request()

server_activate()

server_bind()

verify_request()

요청 처리기 객체

BaseRequestHandler

setup()

handle()

finish()

request

client_address

server

StreamRequestHandler

DatagramRequestHandler

rfile

wfile

예

socketserver.TCPServer 예

socketserver.UDPServer 예

비동기 믹스인

http.server — HTTP servers

HTTPServer

ThreadingHTTPServer

BaseHTTPRequestHandler

client_address

server

close_connection

requestline

command

path

request_version

headers

rfile

wfile

server_version

sys_version

error_message_format

error_content_type

protocol_version

MessageClass

responses

handle()

handle_one_request()

handle_expect_100()

send_error()

send_response()

send_header()

send_response_only()

end_headers()

flush_headers()

log_request()

log_error()

log_message()

version_string()

date_time_string()

log_date_time_string()

address_string()

SimpleHTTPRequestHandler

server_version

extensions_map

do_HEAD()

do_GET()

CGIHTTPRequestHandler

cgi_directories

do_POST()

Security Considerations

http.cookies — HTTP state management

CookieError

BaseCookie

SimpleCookie

쿠키 객체

value_decode()

value_encode()

output()

js_output()

load()

Morsel 객체

Morsel

expires

path

comment

domain

secure

version

httponly

samesite

value

coded_value

key

set()

isReservedKey()

output()

js_output()

OutputString()

update()

copy()

setdefault()

예제

http.cookiejar — Cookie handling for HTTP clients

LoadError

CookieJar

FileCookieJar

CookiePolicy

DefaultCookiePolicy

Cookie

CookieJar와 FileCookieJar 객체

add_cookie_header()

extract_cookies()

set_policy()

make_cookies()

set_cookie_if_ok()

set_cookie()

clear()

clear_session_cookies()

save()

load()

revert()

filename

delayload

FileCookieJar 서브 클래스와 웹 브라우저와의 협력

MozillaCookieJar

LWPCookieJar

CookiePolicy 객체

set_ok()

return_ok()

domain_return_ok()

path_return_ok()

netscape

rfc2965

hide_cookie2

DefaultCookiePolicy 객체

blocked_domains()

set_blocked_domains()

is_blocked()

allowed_domains()

set_allowed_domains()

is_not_allowed()

rfc2109_as_netscape

strict_domain

strict_rfc2965_unverifiable

strict_ns_unverifiable

strict_ns_domain

strict_ns_set_initial_dollar

strict_ns_set_path

DomainStrictNoDots

DomainStrictNonDomain

DomainRFC2965Match

DomainLiberal

DomainStrict

Cookie 객체

version

name

value

port

domain

path

secure

expires

discard

comment

comment_url

rfc2109

port_specified

domain_specified

domain_initial_dot

has_nonstandard_attr()

get_nonstandard_attr()

set_nonstandard_attr()

is_expired()

예

xmlrpc — XMLRPC server and client modules

xmlrpc.client — XML-RPC client access

ServerProxy

ServerProxy 객체

listMethods()

methodSignature()

methodHelp()

DateTime 객체

DateTime

decode()

encode()

Binary 객체

Binary

data

decode()

encode()

Fault 객체

Fault

faultCode

faultString

ProtocolError 객체

ProtocolError

url

errcode

errmsg

headers

MultiCall 객체

MultiCall

편의 함수

dumps()

loads()

클라이언트 사용 예

클라이언트와 서버 사용 예

xmlrpc.server — Basic XML-RPC servers

SimpleXMLRPCServer

CGIXMLRPCRequestHandler

SimpleXMLRPCRequestHandler

SimpleXMLRPCServer 객체

register_function()

register_instance()

register_introspection_functions()

register_multicall_functions()

rpc_paths

SimpleXMLRPCServer 예제

CGIXMLRPCRequestHandler

register_function()

register_instance()

register_introspection_functions()

register_multicall_functions()

handle_request()

XMLRPC 서버 문서화

DocXMLRPCServer

DocCGIXMLRPCRequestHandler

DocXMLRPCRequestHandler

DocXMLRPCServer 객체

set_server_title()

set_server_name()

set_server_documentation()

DocCGIXMLRPCRequestHandler

set_server_title()

set_server_name()

set_server_documentation()

ipaddress — IPv4/IPv6 manipulation library

편의 팩토리 함수

ip_address()

ip_network()

ip_interface()

IP 주소

주소 객체

IPv4Address

version

max_prefixlen

compressed

exploded

packed

reverse_pointer

is_multicast

is_private

is_global

is_unspecified

is_reserved

is_loopback

is_link_local

ipv6_mapped

__format__()

IPv6Address

compressed

exploded

packed

reverse_pointer

version

max_prefixlen

is_multicast

is_private

is_global

is_unspecified

is_reserved

is_loopback

is_link_local

is_site_local

ipv4_mapped

scope_id

sixtofour

teredo

__format__()

문자열과 정수로의 변환

연산자

비교 연산자

산술 연산자

IP 네트워크 정의

접두사, 네트 마스크 및 호스트 마스크

네트워크 객체

IPv4Network

version

max_prefixlen

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

network_address

broadcast_address

hostmask

netmask

with_prefixlen

compressed

exploded

with_netmask

with_hostmask

num_addresses

prefixlen

hosts()

overlaps()

address_exclude()

subnets()

supernet()

subnet_of()

supernet_of()

compare_networks()

IPv6Network

version

max_prefixlen

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

network_address

broadcast_address

hostmask

netmask

with_prefixlen

compressed

exploded

with_netmask

with_hostmask

num_addresses

prefixlen

hosts()

overlaps()

address_exclude()

subnets()

supernet()

subnet_of()

supernet_of()

compare_networks()

is_site_local

연산자

논리 연산자

이터레이션

주소 컨테이너로서의 네트워크

인터페이스 객체

IPv4Interface

ip

network

with_prefixlen

with_netmask

with_hostmask

IPv6Interface

ip

network

with_prefixlen

with_netmask

with_hostmask

연산자

논리 연산자

다른 모듈 수준 함수

v4_int_to_packed()

v6_int_to_packed()

summarize_address_range()

collapse_addresses()

get_mixed_type_key()

맞춤 예외

AddressValueError

NetmaskValueError

멀티미디어 서비스

wave — Read and write WAV files

open()

Error

Wave_read 객체

Wave_read

close()

getnchannels()

getsampwidth()

getframerate()

getnframes()

getcomptype()

getcompname()

getparams()

readframes()

rewind()

getmarkers()

getmark()

setpos()

tell()

Wave_write 객체

Wave_write

close()

setnchannels()

setsampwidth()

setframerate()

setnframes()

setcomptype()

setparams()

tell()

writeframesraw()

writeframes()

colorsys — Conversions between color systems

rgb_to_yiq()

yiq_to_rgb()

rgb_to_hls()

hls_to_rgb()

rgb_to_hsv()

hsv_to_rgb()

국제화

gettext — Multilingual internationalization services

GNU gettext API

bindtextdomain()

textdomain()

gettext()

dgettext()

ngettext()

dngettext()

pgettext()

dpgettext()

npgettext()

dnpgettext()

클래스 기반 API

find()

translation()

install()

NullTranslations 클래스

NullTranslations

_parse()

add_fallback()

gettext()

ngettext()

pgettext()

npgettext()

info()

charset()

install()

GNUTranslations 클래스

GNUTranslations

gettext()

ngettext()

pgettext()

npgettext()

Solaris 메시지 카탈로그 지원

Catalog 생성자

프로그램과 모듈의 국제화

모듈 현지화

응용 프로그램 현지화

실행 중 언어 변경

지연된 번역

감사의 말

locale — Internationalization services

Error

setlocale()

localeconv()

nl_langinfo()

CODESET

D_T_FMT

D_FMT

T_FMT

T_FMT_AMPM

DAY_1

DAY_2

DAY_3

DAY_4

DAY_5

DAY_6

DAY_7

ABDAY_1

ABDAY_2

ABDAY_3

ABDAY_4

ABDAY_5

ABDAY_6

ABDAY_7

MON_1

MON_2

MON_3

MON_4

MON_5

MON_6

MON_7

MON_8

MON_9

MON_10

MON_11

MON_12

ABMON_1

ABMON_2

ABMON_3

ABMON_4

ABMON_5

ABMON_6

ABMON_7

ABMON_8

ABMON_9

ABMON_10

ABMON_11

ABMON_12

RADIXCHAR

THOUSEP

YESEXPR

NOEXPR

CRNCYSTR

ERA

ERA_D_T_FMT

ERA_D_FMT

ERA_T_FMT

ALT_DIGITS

getdefaultlocale()

getlocale()

getpreferredencoding()

getencoding()

normalize()

strcoll()

strxfrm()

format_string()

currency()

str()

delocalize()

localize()

atof()

atoi()

LC_CTYPE

LC_COLLATE

LC_TIME

LC_MONETARY

LC_MESSAGES

LC_NUMERIC

LC_ALL

CHAR_MAX

배경, 세부 사항, 힌트, 팁 및 경고

확장 작성자와 파이썬을 내장하는 프로그램의 경우

메시지 카탈로그에 액세스

gettext()

dgettext()

dcgettext()

textdomain()

bindtextdomain()

bind_textdomain_codeset()

프로그램 프레임워크

turtle — 터틀 그래픽

소개

Get started

Tutorial

Starting a turtle environment

Basic drawing

펜 제어

The turtle’s position

Making algorithmic patterns

How to…

Get started as quickly as possible

Use the turtle module namespace

Use turtle graphics in a script

Use object-oriented turtle graphics

Turtle graphics reference

Turtle 메서드

TurtleScreen/Screen의 메서드

RawTurtle/Turtl의 메서드와 해당 함수

거북이 움직임

forward()

fd()

back()

bk()

backward()

right()

rt()

left()

lt()

goto()

setpos()

setposition()

teleport()

setx()

sety()

setheading()

seth()

home()

circle()

dot()

stamp()

clearstamp()

clearstamps()

undo()

speed()

거북이의 상태 보고

position()

pos()

towards()

xcor()

ycor()

heading()

distance()

측정 설정

degrees()

radians()

펜 제어

그리기 상태

pendown()

pd()

down()

penup()

pu()

up()

pensize()

width()

pen()

isdown()

색상 제어

pencolor()

fillcolor()

color()

채우기

filling()

begin_fill()

end_fill()

더 많은 그리기 제어

reset()

clear()

write()

거북이 상태

가시성

hideturtle()

ht()

showturtle()

st()

isvisible()

외관

shape()

resizemode()

shapesize()

turtlesize()

shearfactor()

tilt()

tiltangle()

shapetransform()

get_shapepoly()

이벤트 사용하기

onrelease()

ondrag()

특수 Turtle 메서드

begin_poly()

end_poly()

get_poly()

clone()

getturtle()

getpen()

getscreen()

setundobuffer()

undobufferentries()

복합 모양

TurtleScreen/Screen 메서드와 해당 함수

창 제어

bgcolor()

bgpic()

clearscreen()

resetscreen()

screensize()

setworldcoordinates()

애니메이션 제어

delay()

tracer()

update()

화면 이벤트 사용하기

listen()

onkey()

onkeyrelease()

onkeypress()

onclick()

onscreenclick()

ontimer()

mainloop()

done()

입력 메서드

textinput()

numinput()

설정과 특수 메서드

mode()

colormode()

getcanvas()

getshapes()

register_shape()

addshape()

turtles()

window_height()

window_width()

TurtleScreen에서 상속되지 않은, Screen만의 메서드

bye()

exitonclick()

save()

setup()

title()

공개 클래스

RawTurtle

RawPen

Turtle

TurtleScreen

Screen

ScrolledCanvas

Shape

addcomponent()

Vec2D

Explanation

도움말과 구성

도움말 사용법

독스트링을 다른 언어로 번역

write_docstringdict()

Screen과 Turtle을 구성하는 방법

turtledemo — 데모 스크립트

파이썬 2.6 이후의 변화

파이썬 3.0 이후의 변화

cmd — Support for line-oriented command interpreters

Cmd

Cmd 객체

cmdloop()

do_help()

onecmd()

emptyline()

default()

completedefault()

columnize()

precmd()

postcmd()

preloop()

postloop()

prompt

identchars

lastcmd

cmdqueue

intro

doc_header

misc_header

undoc_header

ruler

use_rawinput

Cmd 예

shlex — Simple lexical analysis

split()

join()

quote()

shlex

shlex 객체

get_token()

push_token()

read_token()

sourcehook()

push_source()

pop_source()

error_leader()

commenters

wordchars

whitespace

escape

quotes

escapedquotes

whitespace_split

infile

instream

source

debug

lineno

token

eof

punctuation_chars

구문 분석 규칙

셸과의 호환성 향상

Tk를 사용한 그래픽 사용자 인터페이스

tkinter — Python interface to Tcl/Tk

Architecture

Tkinter 모듈

Tk

tk

master

children

Tcl()

Tkinter 구명조끼

A Hello World Program

Important Tk Concepts

Understanding How Tkinter Wraps Tcl/Tk

How do I…? What option does…?

Navigating the Tcl/Tk Reference Manual

Threading model

간편한 레퍼런스

옵션 설정

패커

패커 옵션

위젯 변수 결합하기

창 관리자

Tk 옵션 데이터형

바인딩과 이벤트

index 매개 변수

이미지

파일 처리기

createfilehandler()

deletefilehandler()

READABLE

WRITABLE

EXCEPTION

tkinter.colorchooser — Color choosing dialog

Chooser

askcolor()

tkinter.font — Tkinter font wrapper

NORMAL

BOLD

ITALIC

ROMAN

Font

actual()

cget()

config()

copy()

measure()

metrics()

families()

names()

nametofont()

Tkinter 대화 상자

tkinter.simpledialog — 표준 Tkinter 입력 대화 상자

askfloat()

askinteger()

askstring()

Dialog

body()

buttonbox()

tkinter.filedialog — 파일 선택 대화 상자

네이티브 로드/저장 대화 상자

askopenfile()

askopenfiles()

asksaveasfile()

askopenfilename()

askopenfilenames()

asksaveasfilename()

askdirectory()

Open

SaveAs

Directory

FileDialog

cancel_command()

dirs_double_event()

dirs_select_event()

files_double_event()

files_select_event()

filter_command()

get_filter()

get_selection()

go()

ok_event()

quit()

set_filter()

set_selection()

LoadFileDialog

ok_command()

SaveFileDialog

ok_command()

tkinter.commondialog — 대화창 템플릿

Dialog

show()

tkinter.messagebox — Tkinter message prompts

Message

show()

showinfo()

showwarning()

showerror()

askquestion()

askokcancel()

askretrycancel()

askyesno()

askyesnocancel()

ABORT

RETRY

IGNORE

OK

CANCEL

YES

NO

ABORTRETRYIGNORE

OKCANCEL

RETRYCANCEL

YESNO

YESNOCANCEL

ERROR

INFO

QUESTION

WARNING

tkinter.scrolledtext — Scrolled Text Widget

ScrolledText

frame

vbar

tkinter.dnd — Drag and drop support

DndHandler

cancel()

finish()

on_motion()

on_release()

dnd_start()

tkinter.ttk — Tk themed widgets

Ttk 사용하기

Ttk 위젯

Widget

표준 옵션

스크롤 가능한 위젯 옵션

레이블 옵션

호환성 옵션

위젯 상태

ttk.Widget

Widget

identify()

instate()

state()

Combobox

옵션

가상 이벤트

ttk.Combobox

Combobox

current()

get()

set()

Spinbox

옵션

가상 이벤트

ttk.Spinbox

Spinbox

get()

set()

Notebook

옵션

탭 옵션

탭 식별자

가상 이벤트

ttk.Notebook

Notebook

add()

forget()

hide()

identify()

index()

insert()

select()

tab()

tabs()

enable_traversal()

Progressbar

옵션

ttk.Progressbar

Progressbar

start()

step()

stop()

Separator

옵션

Sizegrip

플랫폼별 노트

버그

Treeview

옵션

항목 옵션

태그 옵션

열 식별자

가상 이벤트

ttk.Treeview

Treeview

bbox()

get_children()

set_children()

column()

delete()

detach()

exists()

focus()

heading()

identify()

identify_row()

identify_column()

identify_region()

identify_element()

index()

insert()

item()

move()

next()

parent()

prev()

reattach()

see()

selection()

selection_set()

selection_add()

selection_remove()

selection_toggle()

set()

tag_bind()

tag_configure()

tag_has()

xview()

yview()

Ttk 스타일링

Style

configure()

map()

lookup()

layout()

element_create()

element_names()

element_options()

theme_create()

theme_settings()

theme_names()

theme_use()

레이아웃

IDLE

메뉴

File 메뉴 (셸과 편집기)

Edit 메뉴 (셸과 편집기)

Format 메뉴 (편집기 창 전용)

Run 메뉴 (편집기 창 전용)

Shell 메뉴 (셸 창 전용)

Debug 메뉴 (셸 창 전용)

Options 메뉴 (셸과 편집기)

Window 메뉴 (셸과 편집기)

Help 메뉴 (셸과 편집기)

Context menus

Editing and Navigation

편집기 창

키 바인딩

자동 들여쓰기

Search and Replace

완성

콜팁

코드 컨텍스트

Shell window

텍스트 색상

Startup and Code Execution

명령 줄 사용법

시작 실패

사용자 코드 실행하기

셸의 사용자 출력

tkinter 응용 프로그램 개발하기

서브 프로세스 없이 실행하기

Help and Preferences

도움말 소스

환경 설정

macOS의 IDLE

확장

idlelib

개발 도구

typing — 형 힌트 지원

Specification for the Python Type System

형 에일리어스

NewType

Annotating callable objects

제네릭

Annotating tuples

The type of class objects

Annotating generators and coroutines

사용자 정의 제네릭 형

Any 형

명목적 대 구조적 서브 타이핑

모듈 내용

특수 타이핑 프리미티브

특수형

Any

AnyStr

LiteralString

Never

NoReturn

Self

TypeAlias

특수 형태

Union

Optional

Concatenate

Literal

ClassVar

Final

Required

NotRequired

ReadOnly

Annotated

TypeIs

TypeGuard

Unpack

Building generic types and type aliases

Generic

TypeVar

__name__

__covariant__

__contravariant__

__infer_variance__

__bound__

evaluate_bound()

__constraints__

evaluate_constraints()

__default__

evaluate_default()

has_default()

TypeVarTuple

__name__

__default__

evaluate_default()

has_default()

ParamSpec

args

kwargs

__name__

__default__

evaluate_default()

has_default()

ParamSpecArgs

ParamSpecKwargs

TypeAliasType

__name__

__module__

__type_params__

__value__

evaluate_value()

기타 특수 지시자

NamedTuple

NewType

__module__

__name__

__supertype__

Protocol

runtime_checkable()

TypedDict

__total__

__required_keys__

__optional_keys__

__readonly_keys__

__mutable_keys__

프로토콜

SupportsAbs

SupportsBytes

SupportsComplex

SupportsFloat

SupportsIndex

SupportsInt

SupportsRound

ABCs for working with IO

IO

TextIO

BinaryIO

함수와 데코레이터

cast()

assert_type()

assert_never()

reveal_type()

dataclass_transform()

overload()

get_overloads()

clear_overloads()

final()

no_type_check()

no_type_check_decorator()

override()

type_check_only()

인트로스펙션 도우미

get_type_hints()

get_origin()

get_args()

get_protocol_members()

is_protocol()

is_typeddict()

ForwardRef

evaluate_forward_ref()

NoDefault

상수

TYPE_CHECKING

Deprecated aliases

Aliases to built-in types

Dict

List

Set

FrozenSet

Tuple

Type

Aliases to types in collections

DefaultDict

OrderedDict

ChainMap

Counter

Deque

Aliases to other concrete types

Pattern

Match

Text

Aliases to container ABCs in collections.abc

AbstractSet

Collection

Container

ItemsView

KeysView

Mapping

MappingView

MutableMapping

MutableSequence

MutableSet

Sequence

ValuesView

Aliases to asynchronous ABCs in collections.abc

Coroutine

AsyncGenerator

AsyncIterable

AsyncIterator

Awaitable

Aliases to other ABCs in collections.abc

Iterable

Iterator

Callable

Generator

Hashable

Reversible

Sized

Aliases to contextlib ABCs

ContextManager

AsyncContextManager

Deprecation Timeline of Major Features

pydoc — Documentation generator and online help system

파이썬 개발 모드

파이썬 개발 모드의 효과

ResourceWarning 예

잘못된 파일 기술자 에러 예

doctest — Test interactive Python examples

간단한 사용법: 독스트링에 있는 예제 확인하기

간단한 사용법: 텍스트 파일에 있는 예제 확인하기

작동 방법

어떤 독스트링을 검사합니까?

독스트링 예제는 어떻게 인식됩니까?

실행 컨텍스트란 무엇입니까?

예외는 어떻게 됩니까?

옵션 플래그

DONT_ACCEPT_TRUE_FOR_1

DONT_ACCEPT_BLANKLINE

NORMALIZE_WHITESPACE

ELLIPSIS

IGNORE_EXCEPTION_DETAIL

SKIP

COMPARISON_FLAGS

REPORT_UDIFF

REPORT_CDIFF

REPORT_NDIFF

REPORT_ONLY_FIRST_FAILURE

FAIL_FAST

REPORTING_FLAGS

register_optionflag()

지시자

경고

기본 API

testfile()

testmod()

run_docstring_examples()

Unittest API

DocFileSuite()

DocTestSuite()

failureException

set_unittest_reportflags()

고급 API

DocTest 객체

DocTest

examples

globs

name

filename

lineno

docstring

Example 객체

Example

source

want

exc_msg

lineno

indent

options

DocTestFinder 객체

DocTestFinder

find()

DocTestParser 객체

DocTestParser

get_doctest()

get_examples()

parse()

TestResults objects

TestResults

failed

attempted

skipped

DocTestRunner 객체

DocTestRunner

report_start()

report_success()

report_failure()

report_unexpected_exception()

run()

summarize()

tries

failures

skips

OutputChecker 객체

OutputChecker

check_output()

output_difference()

디버깅

script_from_examples()

testsource()

debug()

debug_src()

DebugRunner

DocTestFailure

test

example

got

UnexpectedException

test

example

exc_info

맺음말

unittest — Unit testing framework

기본 예시

명령행 인터페이스

명령행 옵션

테스트 탐색(Discovery)

테스트 코드 구조 잡기

이전의 테스트 코드를 다시 사용하기

테스트 건너뛰기와 예상된 실패

skip()

skipIf()

skipUnless()

expectedFailure()

SkipTest

부분 테스트(subtest)를 사용하여 테스트 반복 구별 짓기

클래스와 함수

테스트 케이스

TestCase

setUp()

tearDown()

setUpClass()

tearDownClass()

run()

skipTest()

subTest()

debug()

assertEqual()

assertNotEqual()

assertTrue()

assertFalse()

assertIs()

assertIsNot()

assertIsNone()

assertIsNotNone()

assertIn()

assertNotIn()

assertIsInstance()

assertNotIsInstance()

assertRaises()

assertRaisesRegex()

assertWarns()

assertWarnsRegex()

assertLogs()

records

output

assertNoLogs()

assertAlmostEqual()

assertNotAlmostEqual()

assertGreater()

assertGreaterEqual()

assertLess()

assertLessEqual()

assertRegex()

assertNotRegex()

assertCountEqual()

addTypeEqualityFunc()

assertMultiLineEqual()

assertSequenceEqual()

assertListEqual()

assertTupleEqual()

assertSetEqual()

assertDictEqual()

fail()

failureException

longMessage

maxDiff

countTestCases()

defaultTestResult()

id()

shortDescription()

addCleanup()

enterContext()

doCleanups()

addClassCleanup()

enterClassContext()

doClassCleanups()

IsolatedAsyncioTestCase

loop_factory

asyncSetUp()

asyncTearDown()

addAsyncCleanup()

enterAsyncContext()

run()

FunctionTestCase

테스트 분류

TestSuite

addTest()

addTests()

run()

debug()

countTestCases()

__iter__()

테스트를 로드하고 실행하기

TestLoader

errors

loadTestsFromTestCase()

loadTestsFromModule()

loadTestsFromName()

loadTestsFromNames()

getTestCaseNames()

discover()

testMethodPrefix

sortTestMethodsUsing

suiteClass

testNamePatterns

TestResult

errors

failures

skipped

expectedFailures

unexpectedSuccesses

collectedDurations

shouldStop

testsRun

buffer

failfast

tb_locals

wasSuccessful()

stop()

startTest()

stopTest()

startTestRun()

stopTestRun()

addError()

addFailure()

addSuccess()

addSkip()

addExpectedFailure()

addUnexpectedSuccess()

addSubTest()

addDuration()

TextTestResult

defaultTestLoader

TextTestRunner

_makeResult()

run()

main()

load_tests 프로토콜

클래스와 모듈 픽스쳐

setUpClass 와 tearDownClass

setUpModule 과 tearDownModule

addModuleCleanup()

enterModuleContext()

doModuleCleanups()

시그널 처리하기

installHandler()

registerResult()

removeResult()

removeHandler()

unittest.mock — mock object library

간략 지침

Mock 클래스

Mock

assert_called()

assert_called_once()

assert_called_with()

assert_called_once_with()

assert_any_call()

assert_has_calls()

assert_not_called()

reset_mock()

mock_add_spec()

attach_mock()

configure_mock()

__dir__()

_get_child_mock()

called

call_count

return_value

side_effect

call_args

call_args_list

method_calls

mock_calls

__class__

NonCallableMock

PropertyMock

AsyncMock

assert_awaited()

assert_awaited_once()

assert_awaited_with()

assert_awaited_once_with()

assert_any_await()

assert_has_awaits()

assert_not_awaited()

reset_mock()

await_count

await_args

await_args_list

ThreadingMock

wait_until_called()

wait_until_any_call_with()

DEFAULT_TIMEOUT

호출

어트리뷰트 삭제

모의 객체 이름과 이름 어트리뷰트

모의 객체를 어트리뷰트로 연결하기

패처

patch

patch()

patch.object

object()

patch.dict

dict()

patch.multiple

multiple()

패처 메서드: start와 stop

stopall()

내장 패치

TEST_PREFIX

패치 데코레이터 중첩하기

패치할 곳

디스크립터와 프락시 객체 패치하기

MagicMock과 매직 메서드 지원

매직 메서드 모킹하기

매직 모의 객체

MagicMock

NonCallableMagicMock

도우미

sentinel

sentinel

DEFAULT

DEFAULT

call

call()

call_list()

create_autospec

create_autospec()

ANY

ANY

FILTER_DIR

FILTER_DIR

mock_open

mock_open()

자동 사양

실링 모의 객체 봉인하기

seal()

Order of precedence of side_effect, return_value and wraps

unittest.mock — getting started

모의 객체 사용하기

메서드를 패치하는 모의 객체

객체의 메서드 호출을 위한 모의 객체

클래스 모킹하기

모의 객체 이름 붙이기

모든 호출 추적하기

반환 값과 어트리뷰트 설정하기

모의 객체로 예외 발생시키기

부작용 함수와 이터러블

비동기 이터레이터 모킹하기

비동기 컨텍스트 관리자 모킹하기

기존 객체에서 모의 객체 만들기

Using side_effect to return per file content

패치 데코레이터

추가 예

연쇄 호출 모킹하기

부분 모킹

제너레이터 메서드 모킹하기

모든 테스트 메서드에 같은 패치 적용하기

연결되지 않은 메서드 모킹하기

모의 객체로 여러 호출 확인하기

가변 인자에 대처하기

중첩 패치

MagicMock으로 딕셔너리 모킹하기

Mock 서브 클래스와 그 어트리뷰트

patch.dict로 임포트를 모킹하기

호출 순서 추적과 덜 상세한 호출 어서션

더 복잡한 인자 일치

test — Regression tests package for Python

test 패키지를 위한 단위 테스트 작성하기

명령 줄 인터페이스를 사용하여 테스트 실행하기

test.support — 파이썬 테스트 스위트용 유틸리티

TestFailed

ResourceDenied

verbose

is_jython

is_android

unix_shell

LOOPBACK_TIMEOUT

INTERNET_TIMEOUT

SHORT_TIMEOUT

LONG_TIMEOUT

PGO

PIPE_MAX_SIZE

Py_DEBUG

SOCK_MAX_SIZE

TEST_SUPPORT_DIR

TEST_HOME_DIR

TEST_DATA_DIR

MAX_Py_ssize_t

max_memuse

real_max_memuse

MISSING_C_DOCSTRINGS

HAVE_DOCSTRINGS

TEST_HTTP_URL

ALWAYS_EQ

NEVER_EQ

LARGEST

SMALLEST

busy_retry()

sleeping_retry()

is_resource_enabled()

python_is_optimized()

with_pymalloc()

requires()

sortdict()

findfile()

get_pagesize()

setswitchinterval()

check_impl_detail()

set_memlimit()

record_original_stdout()

get_original_stdout()

args_from_interpreter_flags()

optim_args_from_interpreter_flags()

captured_stdin()

captured_stdout()

captured_stderr()

disable_faulthandler()

gc_collect()

disable_gc()

swap_attr()

swap_item()

flush_std_streams()

print_warning()

wait_process()

calcobjsize()

calcvobjsize()

checksizeof()

anticipate_failure()

system_must_validate_cert()

run_with_locale()

run_with_tz()

requires_freebsd_version()

requires_linux_version()

requires_mac_version()

requires_gil_enabled()

requires_IEEE_754()

requires_zlib()

requires_gzip()

requires_bz2()

requires_lzma()

requires_resource()

requires_docstrings()

requires_limited_api()

cpython_only()

impl_detail()

no_tracing()

refcount_test()

bigmemtest()

bigaddrspacetest()

check_syntax_error()

open_urlresource()

reap_children()

get_attribute()

catch_unraisable_exception()

load_package_tests()

detect_api_mismatch()

patch()

run_in_subinterp()

check_free_after_iterating()

missing_compiler_executable()

check__all__()

skip_if_broken_multiprocessing_synchronize()

check_disallow_instantiation()

adjust_int_max_str_digits()

SuppressCrashReport

SaveSignals

save()

restore()

Matcher

matches()

match_value()

test.support.socket_helper — 소켓 테스트용 유틸리티

IPV6_ENABLED

find_unused_port()

bind_port()

bind_unix_socket()

skip_unless_bind_unix_socket()

transient_internet()

test.support.script_helper — 파이썬 실행 테스트용 유틸리티

interpreter_requires_environment()

run_python_until_end()

assert_python_ok()

assert_python_failure()

spawn_python()

kill_python()

make_script()

make_zip_script()

make_pkg()

make_zip_pkg()

test.support.bytecode_helper — 올바른 바이트 코드 생성 테스트를 위한 지원 도구

BytecodeTestCase

get_disassembly_as_string()

assertInBytecode()

assertNotInBytecode()

test.support.threading_helper — Utilities for threading tests

join_thread()

reap_threads()

start_threads()

threading_cleanup()

threading_setup()

wait_threads_exit()

catch_threading_exception()

test.support.os_helper — Utilities for os tests

FS_NONASCII

SAVEDCWD

TESTFN

TESTFN_NONASCII

TESTFN_UNENCODABLE

TESTFN_UNDECODABLE

TESTFN_UNICODE

EnvironmentVarGuard

FakePath

set()

unset()

can_symlink()

can_xattr()

change_cwd()

create_empty_file()

fd_count()

fs_is_case_insensitive()

make_bad_fd()

rmdir()

rmtree()

skip_unless_symlink()

skip_unless_xattr()

temp_cwd()

temp_dir()

temp_umask()

unlink()

test.support.import_helper — Utilities for import tests

forget()

import_fresh_module()

import_module()

modules_setup()

modules_cleanup()

unload()

make_legacy_pyc()

CleanImport

DirsOnSysPath

test.support.warnings_helper — Utilities for warnings tests

ignore_warnings()

check_no_resource_warning()

check_syntax_warning()

check_warnings()

WarningsRecorder

디버깅과 프로파일링

감사 이벤트 표

bdb — Debugger framework

BdbQuit

Breakpoint

deleteMe()

enable()

disable()

bpformat()

bpprint()

file

line

temporary

cond

funcname

enabled

bpbynumber

bplist

ignore

hits

Bdb

canonic()

reset()

trace_dispatch()

dispatch_line()

dispatch_call()

dispatch_return()

dispatch_exception()

is_skipped_line()

stop_here()

break_here()

break_anywhere()

user_call()

user_line()

user_return()

user_exception()

do_clear()

set_step()

set_next()

set_return()

set_until()

set_trace()

set_continue()

set_quit()

set_break()

clear_break()

clear_bpbynumber()

clear_all_file_breaks()

clear_all_breaks()

get_bpbynumber()

get_break()

get_breaks()

get_file_breaks()

get_all_breaks()

get_stack()

format_stack_entry()

run()

runeval()

runctx()

runcall()

checkfuncname()

effective()

set_trace()

faulthandler — Dump the Python traceback

트레이스백 덤프하기

dump_traceback()

결함 처리기 상태

enable()

disable()

is_enabled()

시간 초과 후에 트레이스백 덤프하기

dump_traceback_later()

cancel_dump_traceback_later()

사용자 시그널에 트레이스백 덤프하기

register()

unregister()

파일 기술자 관련 문제

예제

pdb — 파이썬 디버거

run()

runeval()

runcall()

set_trace()

post_mortem()

pm()

Pdb

run()

runeval()

runcall()

set_trace()

디버거 명령들

파이썬 프로파일러

프로파일러 소개

즉석 사용자 설명서

profile과 cProfile 모듈 레퍼런스

run()

runctx()

Profile

enable()

disable()

create_stats()

print_stats()

dump_stats()

run()

runctx()

runcall()

Stats 클래스

Stats

strip_dirs()

add()

dump_stats()

sort_stats()

reverse_order()

print_stats()

print_callers()

print_callees()

get_stats_profile()

결정론적 프로파일링이란 무엇입니까?

한계

보정

사용자 정의 타이머 사용하기

timeit — Measure execution time of small code snippets

기본 예제

파이썬 인터페이스

timeit()

repeat()

default_timer()

Timer

timeit()

autorange()

repeat()

print_exc()

명령 줄 인터페이스

예제

trace — Trace or track Python statement execution

명령 줄 사용법

주요 옵션

수정자

필터

프로그래밍 인터페이스

Trace

run()

runctx()

runfunc()

results()

CoverageResults

update()

write_results()

tracemalloc — Trace memory allocations

예

상위 10개 표시

차이 계산

메모리 블록의 트레이스백 얻기

예쁜 탑(top)

모든 추적한 메모리 블록의 현재 및 최대 크기를 기록

API

함수

clear_traces()

get_object_traceback()

get_traceback_limit()

get_traced_memory()

reset_peak()

get_tracemalloc_memory()

is_tracing()

start()

stop()

take_snapshot()

DomainFilter

DomainFilter

inclusive

domain

Filter

Filter

domain

inclusive

lineno

filename_pattern

all_frames

Frame

Frame

filename

lineno

Snapshot

Snapshot

compare_to()

dump()

filter_traces()

load()

statistics()

traceback_limit

traces

Statistic

Statistic

count

size

traceback

StatisticDiff

StatisticDiff

count

count_diff

size

size_diff

traceback

Trace

Trace

domain

size

traceback

Traceback

Traceback

total_nframe

format()

소프트웨어 패키징 및 배포

ensurepip — Bootstrapping the pip installer

명령 줄 인터페이스

모듈 API

version()

bootstrap()

venv — Creation of virtual environments

가상 환경 만들기

How venvs work

API

EnvBuilder

create()

ensure_directories()

create_configuration()

setup_python()

setup_scripts()

upgrade_dependencies()

post_setup()

install_scripts()

create_git_ignore_file()

create()

EnvBuilder 확장 예제

zipapp — Manage executable Python zip archives

기본 예

명령 줄 인터페이스

파이썬 API

create_archive()

get_interpreter()

예

인터프리터 지정하기

zipapp으로 독립형 응용 프로그램 만들기

경고

파이썬 Zip 응용 프로그램 아카이브 형식

파이썬 실행시간 서비스

sys — System-specific parameters and functions

abiflags

addaudithook()

argv

audit()

base_exec_prefix

base_prefix

byteorder

builtin_module_names

call_tracing()

copyright

_clear_type_cache()

_clear_internal_caches()

_current_frames()

_current_exceptions()

breakpointhook()

_debugmallocstats()

dllhandle

displayhook()

dont_write_bytecode

_emscripten_info

emscripten_version

runtime

pthreads

shared_memory

pycache_prefix

excepthook()

__breakpointhook__

__displayhook__

__excepthook__

__unraisablehook__

exception()

exc_info()

exec_prefix

executable

exit()

flags

debug

inspect

interactive

isolated

optimize

dont_write_bytecode

no_user_site

no_site

ignore_environment

verbose

bytes_warning

quiet

hash_randomization

dev_mode

utf8_mode

safe_path

int_max_str_digits

warn_default_encoding

float_info

epsilon

dig

mant_dig

max

max_exp

max_10_exp

min

min_exp

min_10_exp

radix

rounds

float_repr_style

getallocatedblocks()

getunicodeinternedsize()

getandroidapilevel()

getdefaultencoding()

getdlopenflags()

getfilesystemencoding()

getfilesystemencodeerrors()

get_int_max_str_digits()

getrefcount()

getrecursionlimit()

getsizeof()

getswitchinterval()

_getframe()

_getframemodulename()

getobjects()

getprofile()

gettrace()

getwindowsversion()

get_asyncgen_hooks()

get_coroutine_origin_tracking_depth()

hash_info

width

modulus

inf

nan

imag

algorithm

hash_bits

seed_bits

hexversion

implementation

int_info

bits_per_digit

sizeof_digit

default_max_str_digits

str_digits_check_threshold

__interactivehook__

intern()

_is_gil_enabled()

is_finalizing()

last_exc

_is_interned()

last_type

last_value

last_traceback

maxsize

maxunicode

meta_path

modules

orig_argv

path

path_hooks

path_importer_cache

platform

platlibdir

prefix

ps1

ps2

setdlopenflags()

set_int_max_str_digits()

setprofile()

setrecursionlimit()

setswitchinterval()

settrace()

set_asyncgen_hooks()

set_coroutine_origin_tracking_depth()

activate_stack_trampoline()

deactivate_stack_trampoline()

is_stack_trampoline_active()

_enablelegacywindowsfsencoding()

stdin

stdout

stderr

__stdin__

__stdout__

__stderr__

stdlib_module_names

thread_info

name

lock

version

tracebacklimit

unraisablehook()

version

api_version

version_info

warnoptions

winver

_xoptions

sys.monitoring — Execution event monitoring

Tool identifiers

Registering and using tools

use_tool_id()

clear_tool_id()

free_tool_id()

get_tool()

Events

Local events

Ancillary events

Other events

The STOP_ITERATION event

Turning events on and off

Setting events globally

get_events()

set_events()

Per code object events

get_local_events()

set_local_events()

Disabling events

DISABLE

restart_events()

Registering callback functions

register_callback()

Callback function arguments

MISSING

sysconfig — Provide access to Python’s configuration information

구성 변수

get_config_vars()

get_config_var()

설치 경로

User scheme

posix_user

nt_user

osx_framework_user

Home scheme

posix_home

Prefix scheme

posix_prefix

nt

Installation path functions

get_scheme_names()

get_default_scheme()

get_preferred_scheme()

_get_preferred_schemes()

get_path_names()

get_path()

get_paths()

기타 함수

get_python_version()

get_platform()

is_python_build()

parse_config_h()

get_config_h_filename()

get_makefile_filename()

sysconfig 를 스크립트로 사용하기

builtins — Built-in objects

__main__ — Top-level code environment

__name__ == '__main__'

What is the “top-level code environment”?

Idiomatic Usage

Packaging Considerations

__main__.py in Python Packages

Idiomatic Usage

import __main__

warnings — Warning control

경고 범주

경고 필터

Repeated Warning Suppression Criteria

경고 필터 설명

기본 경고 필터

기본 필터 재정의

일시적인 경고 억제

경고 테스트

새 버전의 종속성에 대한 코드 갱신

사용 가능한 함수

warn()

warn_explicit()

showwarning()

formatwarning()

filterwarnings()

simplefilter()

resetwarnings()

deprecated()

사용 가능한 컨텍스트 관리자

catch_warnings

dataclasses — Data Classes

Module contents

dataclass()

field()

Field

fields()

asdict()

astuple()

make_dataclass()

replace()

is_dataclass()

MISSING

KW_ONLY

FrozenInstanceError

초기화 후처리

__post_init__()

클래스 변수

초기화 전용 변수

고정 인스턴스

계승

Re-ordering of keyword-only parameters in __init__()

기본 팩토리 함수

가변 기본값

Descriptor-typed fields

contextlib — with 문 컨텍스트를 위한 유틸리티

유틸리티

AbstractContextManager

AbstractAsyncContextManager

contextmanager()

asynccontextmanager()

closing()

aclosing()

nullcontext()

suppress()

redirect_stdout()

redirect_stderr()

chdir()

ContextDecorator

AsyncContextDecorator

ExitStack

enter_context()

push()

callback()

pop_all()

close()

AsyncExitStack

enter_async_context()

push_async_exit()

push_async_callback()

aclose()

예제와 조리법

일정하지 않은 수의 컨텍스트 관리자 지원

__enter__ 메서드에서 발생하는 예외 잡기

__enter__ 구현에서 정리하기

try-finally와 플래그 변수 사용 교체하기

함수 데코레이터로 컨텍스트 관리자 사용하기

일회용, 재사용 가능 및 재진입 가능 컨텍스트 관리자

재진입 가능 컨텍스트 관리자

재사용 가능 컨텍스트 관리자

abc — Abstract Base Classes

ABC

ABCMeta

register()

__subclasshook__()

abstractmethod()

abstractclassmethod()

abstractstaticmethod()

abstractproperty()

get_cache_token()

update_abstractmethods()

atexit — Exit handlers

register()

unregister()

atexit 예제

traceback — Print or retrieve a stack traceback

Module-Level Functions

print_tb()

print_exception()

print_exc()

print_last()

print_stack()

extract_tb()

extract_stack()

format_list()

format_exception_only()

format_exception()

format_exc()

format_tb()

format_stack()

clear_frames()

walk_stack()

walk_tb()

TracebackException Objects

TracebackException

__cause__

__context__

exceptions

__suppress_context__

__notes__

stack

exc_type

exc_type_str

filename

lineno

end_lineno

text

offset

end_offset

msg

from_exception()

print()

format()

format_exception_only()

StackSummary Objects

StackSummary

extract()

from_list()

format()

format_frame_summary()

FrameSummary Objects

FrameSummary

filename

lineno

name

line

Examples of Using the Module-Level Functions

Examples of Using TracebackException

__future__ — Future statement definitions

Module Contents

_Feature

getOptionalRelease()

getMandatoryRelease()

compiler_flag

gc — Garbage Collector interface

enable()

disable()

isenabled()

collect()

set_debug()

get_debug()

get_objects()

get_stats()

set_threshold()

get_count()

get_threshold()

get_referrers()

get_referents()

is_tracked()

is_finalized()

freeze()

unfreeze()

get_freeze_count()

garbage

callbacks

DEBUG_STATS

DEBUG_COLLECTABLE

DEBUG_UNCOLLECTABLE

DEBUG_SAVEALL

DEBUG_LEAK

inspect — Inspect live objects

형과 멤버

getmembers()

getmembers_static()

getmodulename()

ismodule()

isclass()

ismethod()

ispackage()

isfunction()

isgeneratorfunction()

isgenerator()

iscoroutinefunction()

markcoroutinefunction()

iscoroutine()

isawaitable()

isasyncgenfunction()

isasyncgen()

istraceback()

isframe()

iscode()

isbuiltin()

ismethodwrapper()

isroutine()

isabstract()

ismethoddescriptor()

isdatadescriptor()

isgetsetdescriptor()

ismemberdescriptor()

소스 코드 가져오기

getdoc()

getcomments()

getfile()

getmodule()

getsourcefile()

getsourcelines()

getsource()

cleandoc()

Signature 객체로 콜러블 검사하기

signature()

Signature

empty

parameters

return_annotation

bind()

bind_partial()

replace()

format()

from_callable()

Parameter

empty

name

default

annotation

kind

description

replace()

BoundArguments

arguments

args

kwargs

signature

apply_defaults()

클래스와 함수

getclasstree()

getfullargspec()

getargvalues()

formatargvalues()

getmro()

getcallargs()

getclosurevars()

unwrap()

get_annotations()

인터프리터 스택

FrameInfo

frame

filename

lineno

function

code_context

index

positions

Traceback

filename

lineno

function

code_context

index

positions

getframeinfo()

getouterframes()

getinnerframes()

currentframe()

stack()

trace()

정적으로 어트리뷰트 가져오기

getattr_static()

Current State of Generators, Coroutines, and Asynchronous Generators

getgeneratorstate()

getcoroutinestate()

getasyncgenstate()

getgeneratorlocals()

getcoroutinelocals()

getasyncgenlocals()

코드 객체 비트 플래그

CO_OPTIMIZED

CO_NEWLOCALS

CO_VARARGS

CO_VARKEYWORDS

CO_NESTED

CO_GENERATOR

CO_COROUTINE

CO_ITERABLE_COROUTINE

CO_ASYNC_GENERATOR

CO_HAS_DOCSTRING

Buffer flags

BufferFlags

SIMPLE

WRITABLE

FORMAT

ND

STRIDES

C_CONTIGUOUS

F_CONTIGUOUS

ANY_CONTIGUOUS

INDIRECT

CONTIG

CONTIG_RO

STRIDED

STRIDED_RO

RECORDS

RECORDS_RO

FULL

FULL_RO

READ

WRITE

명령 줄 인터페이스

annotationlib — Functionality for introspecting annotations

Annotation semantics

Classes

Format

VALUE

FORWARDREF

STRING

VALUE_WITH_FAKE_GLOBALS

ForwardRef

__forward_arg__

evaluate()

Functions

annotations_to_string()

call_annotate_function()

call_evaluate_function()

get_annotate_function()

get_annotations()

value_to_string()

site — Site-specific configuration hook

sitecustomize

usercustomize

Readline 구성

모듈 내용

PREFIXES

ENABLE_USER_SITE

USER_SITE

USER_BASE

main()

addsitedir()

getsitepackages()

getuserbase()

getusersitepackages()

명령 줄 인터페이스

사용자 정의 파이썬 인터프리터

code — Interpreter base classes

InteractiveInterpreter

InteractiveConsole

interact()

compile_command()

대화형 인터프리터 객체

runsource()

runcode()

showsyntaxerror()

showtraceback()

write()

대화형 콘솔 객체

interact()

push()

resetbuffer()

raw_input()

codeop — Compile Python code

compile_command()

Compile

CommandCompiler

모듈 임포트 하기

zipimport — Import modules from Zip archives

ZipImportError

zipimporter 객체

zipimporter

create_module()

exec_module()

find_spec()

get_code()

get_data()

get_filename()

get_source()

is_package()

load_module()

invalidate_caches()

archive

prefix

예제

pkgutil — Package extension utility

ModuleInfo

extend_path()

get_importer()

iter_importers()

iter_modules()

walk_packages()

get_data()

resolve_name()

modulefinder — Find modules used by a script

AddPackagePath()

ReplacePackage()

ModuleFinder

report()

run_script()

modules

ModuleFinder의 사용 예

runpy — Locating and executing Python modules

run_module()

run_path()

importlib — import의 구현

소개

함수

__import__()

import_module()

invalidate_caches()

reload()

importlib.abc – import와 관련된 추상 베이스 클래스

MetaPathFinder

find_spec()

invalidate_caches()

PathEntryFinder

find_spec()

invalidate_caches()

Loader

create_module()

exec_module()

load_module()

ResourceLoader

get_data()

InspectLoader

get_code()

get_source()

is_package()

source_to_code()

exec_module()

load_module()

ExecutionLoader

get_filename()

FileLoader

name

path

load_module()

get_filename()

get_data()

SourceLoader

path_stats()

path_mtime()

set_data()

get_code()

exec_module()

load_module()

get_source()

is_package()

ResourceReader

open_resource()

resource_path()

is_resource()

contents()

Traversable

name

iterdir()

is_dir()

is_file()

joinpath()

__truediv__()

open()

read_bytes()

read_text()

TraversableResources

files()

importlib.machinery – 임포터와 경로 훅

SOURCE_SUFFIXES

DEBUG_BYTECODE_SUFFIXES

OPTIMIZED_BYTECODE_SUFFIXES

BYTECODE_SUFFIXES

EXTENSION_SUFFIXES

all_suffixes()

BuiltinImporter

FrozenImporter

WindowsRegistryFinder

PathFinder

find_spec()

invalidate_caches()

FileFinder

path

find_spec()

invalidate_caches()

path_hook()

SourceFileLoader

name

path

is_package()

path_stats()

set_data()

load_module()

SourcelessFileLoader

name

path

is_package()

get_code()

get_source()

load_module()

ExtensionFileLoader

name

path

create_module()

exec_module()

is_package()

get_code()

get_source()

get_filename()

NamespaceLoader

ModuleSpec

name

loader

origin

submodule_search_locations

loader_state

cached

parent

has_location

AppleFrameworkLoader

name

path

importlib.util – 임포터를 위한 유틸리티 코드

MAGIC_NUMBER

cache_from_source()

source_from_cache()

decode_source()

resolve_name()

find_spec()

module_from_spec()

spec_from_loader()

spec_from_file_location()

source_hash()

_incompatible_extension_module_restrictions()

LazyLoader

factory()

예

프로그래밍 방식으로 임포트 하기

모듈을 임포트 할 수 있는지 확인하기

소스 파일을 직접 임포트 하기

Implementing lazy imports

임포터 설정하기

importlib.import_module() 근사하기

importlib.resources – Package resource reading, opening and access

Anchor

files()

as_file()

Functional API

open_binary()

open_text()

read_binary()

read_text()

path()

is_resource()

contents()

importlib.resources.abc – Abstract base classes for resources

ResourceReader

open_resource()

resource_path()

is_resource()

contents()

Traversable

name

iterdir()

is_dir()

is_file()

joinpath()

__truediv__()

open()

read_bytes()

read_text()

TraversableResources

files()

importlib.metadata – Accessing package metadata

개요

PackageNotFoundError

기능적 API

진입 지점

entry_points()

EntryPoints

EntryPoint

배포 메타데이터

metadata()

PackageMetadata

배포 버전

version()

배포 파일

files()

PackagePath

배포 요구 사항

requires()

Mapping import to distribution packages

packages_distributions()

배포

distribution()

Distribution

Distribution Discovery

Implementing Custom Providers

Example

The initialization of the sys.path module search path

Virtual Environments

_pth files

Embedded Python

파이썬 언어 서비스

ast — Abstract Syntax Trees

추상 문법

노드 클래스

AST

_fields

_field_types

lineno

col_offset

end_lineno

end_col_offset

Root nodes

Module

Expression

Interactive

FunctionType

리터럴

Constant

FormattedValue

JoinedStr

List

Tuple

Set

Dict

변수

Name

Load

Store

Del

Starred

표현식

Expr

UnaryOp

UAdd

USub

Not

Invert

BinOp

Add

Sub

Mult

Div

FloorDiv

Mod

Pow

LShift

RShift

BitOr

BitXor

BitAnd

MatMult

BoolOp

And

Or

Compare

Eq

NotEq

Lt

LtE

Gt

GtE

Is

IsNot

In

NotIn

Call

keyword

IfExp

Attribute

NamedExpr

서브스크립팅

Subscript

Slice

컴프리헨션

ListComp

SetComp

GeneratorExp

DictComp

comprehension

문장

Assign

type_comment

AnnAssign

AugAssign

Raise

Assert

Delete

Pass

TypeAlias

임포트

Import

ImportFrom

alias

제어 흐름

If

For

type_comment

While

Break

Continue

Try

TryStar

ExceptHandler

With

type_comment

withitem

Pattern matching

Match

match_case

MatchValue

MatchSingleton

MatchSequence

MatchStar

MatchMapping

MatchClass

MatchAs

MatchOr

Type parameters

TypeVar

ParamSpec

TypeVarTuple

함수와 클래스 정의

FunctionDef

type_comment

Lambda

arguments

arg

type_comment

Return

Yield

YieldFrom

Global

Nonlocal

ClassDef

Async와 await

AsyncFunctionDef

Await

AsyncFor

AsyncWith

ast 도우미

parse()

unparse()

literal_eval()

get_docstring()

get_source_segment()

fix_missing_locations()

increment_lineno()

copy_location()

iter_fields()

iter_child_nodes()

walk()

NodeVisitor

visit()

generic_visit()

visit_Constant()

NodeTransformer

dump()

컴파일러 플래그

PyCF_ALLOW_TOP_LEVEL_AWAIT

PyCF_ONLY_AST

PyCF_OPTIMIZED_AST

PyCF_TYPE_COMMENTS

compare()

명령 줄 사용법

symtable — Access to the compiler’s symbol tables

심볼 테이블 생성하기

symtable()

심볼 테이블 검사하기

SymbolTableType

MODULE

FUNCTION

CLASS

ANNOTATION

TYPE_ALIAS

TYPE_PARAMETERS

TYPE_VARIABLE

SymbolTable

get_type()

get_id()

get_name()

get_lineno()

is_optimized()

is_nested()

has_children()

get_identifiers()

lookup()

get_symbols()

get_children()

Function

get_parameters()

get_locals()

get_globals()

get_nonlocals()

get_frees()

Class

get_methods()

Symbol

get_name()

is_referenced()

is_imported()

is_parameter()

is_type_parameter()

is_global()

is_nonlocal()

is_declared_global()

is_local()

is_annotated()

is_free()

is_free_class()

is_assigned()

is_comp_iter()

is_comp_cell()

is_namespace()

get_namespaces()

get_namespace()

Command-Line Usage

token — Constants used with Python parse trees

tok_name

ISTERMINAL()

ISNONTERMINAL()

ISEOF()

ENDMARKER

NAME

NUMBER

STRING

NEWLINE

INDENT

DEDENT

LPAR

RPAR

LSQB

RSQB

COLON

COMMA

SEMI

PLUS

MINUS

STAR

SLASH

VBAR

AMPER

LESS

GREATER

EQUAL

DOT

PERCENT

LBRACE

RBRACE

EQEQUAL

NOTEQUAL

LESSEQUAL

GREATEREQUAL

TILDE

CIRCUMFLEX

LEFTSHIFT

RIGHTSHIFT

DOUBLESTAR

PLUSEQUAL

MINEQUAL

STAREQUAL

SLASHEQUAL

PERCENTEQUAL

AMPEREQUAL

VBAREQUAL

CIRCUMFLEXEQUAL

LEFTSHIFTEQUAL

RIGHTSHIFTEQUAL

DOUBLESTAREQUAL

DOUBLESLASH

DOUBLESLASHEQUAL

AT

ATEQUAL

RARROW

ELLIPSIS

COLONEQUAL

EXCLAMATION

OP

TYPE_IGNORE

TYPE_COMMENT

SOFT_KEYWORD

FSTRING_START

FSTRING_MIDDLE

FSTRING_END

COMMENT

NL

ERRORTOKEN

N_TOKENS

NT_OFFSET

ENCODING

keyword — Testing for Python keywords

iskeyword()

kwlist

issoftkeyword()

softkwlist

tokenize — Tokenizer for Python source

입력 토큰화하기

tokenize()

generate_tokens()

untokenize()

detect_encoding()

open()

TokenError

명령 줄 사용법

예제

tabnanny — Detection of ambiguous indentation

check()

verbose

filename_only

NannyNag

process_tokens()

pyclbr — Python module browser support

readmodule()

readmodule_ex()

Function 객체

Function

file

module

name

lineno

parent

children

is_async

Class 객체

Class

file

module

name

lineno

parent

children

super

methods

py_compile — Compile Python source files

PyCompileError

compile()

PycInvalidationMode

TIMESTAMP

CHECKED_HASH

UNCHECKED_HASH

Command-Line Interface

compileall — Byte-compile Python libraries

명령 줄 사용

공용 함수

compile_dir()

compile_file()

compile_path()

dis — Disassembler for Python bytecode

Command-line interface

바이트 코드 분석

Bytecode

from_traceback()

codeobj

first_line

dis()

info()

분석 함수

code_info()

show_code()

dis()

distb()

disassemble()

disco()

get_instructions()

findlinestarts()

findlabels()

stack_effect()

파이썬 바이트 코드 명령어

Instruction

opcode

opname

baseopcode

baseopname

arg

oparg

argval

argrepr

offset

start_offset

cache_offset

end_offset

starts_line

line_number

is_jump_target

jump_target

positions

Positions

lineno

end_lineno

col_offset

end_col_offset

옵코드 모음

opname

opmap

cmp_op

hasarg

hasconst

hasfree

hasname

hasjump

haslocal

hascompare

hasexc

hasjrel

hasjabs

pickletools — Tools for pickle developers

명령 줄 사용법

명령 줄 옵션

프로그래밍 인터페이스

dis()

genops()

optimize()

MS 윈도우 특정 서비스

msvcrt — Useful routines from the MS VC++ runtime

파일 연산

locking()

LK_LOCK

LK_RLCK

LK_NBLCK

LK_NBRLCK

LK_UNLCK

setmode()

open_osfhandle()

get_osfhandle()

콘솔 I/O

kbhit()

getch()

getwch()

getche()

getwche()

putch()

putwch()

ungetch()

ungetwch()

기타 함수

heapmin()

set_error_mode()

OUT_TO_DEFAULT

OUT_TO_STDERR

OUT_TO_MSGBOX

REPORT_ERRMODE

CrtSetReportMode()

CrtSetReportFile()

CRT_WARN

CRT_ERROR

CRT_ASSERT

CRTDBG_MODE_DEBUG

CRTDBG_MODE_FILE

CRTDBG_MODE_WNDW

CRTDBG_REPORT_MODE

CRT_ASSEMBLY_VERSION

VC_ASSEMBLY_PUBLICKEYTOKEN

LIBRARIES_ASSEMBLY_NAME_PREFIX

winreg — Windows registry access

함수

CloseKey()

ConnectRegistry()

CreateKey()

CreateKeyEx()

DeleteKey()

DeleteKeyEx()

DeleteValue()

EnumKey()

EnumValue()

ExpandEnvironmentStrings()

FlushKey()

LoadKey()

OpenKey()

OpenKeyEx()

QueryInfoKey()

QueryValue()

QueryValueEx()

SaveKey()

SetValue()

SetValueEx()

DisableReflectionKey()

EnableReflectionKey()

QueryReflectionKey()

상수

HKEY_* 상수

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER

HKEY_LOCAL_MACHINE

HKEY_USERS

HKEY_PERFORMANCE_DATA

HKEY_CURRENT_CONFIG

HKEY_DYN_DATA

액세스 권한

KEY_ALL_ACCESS

KEY_WRITE

KEY_READ

KEY_EXECUTE

KEY_QUERY_VALUE

KEY_SET_VALUE

KEY_CREATE_SUB_KEY

KEY_ENUMERATE_SUB_KEYS

KEY_NOTIFY

KEY_CREATE_LINK

64비트 특정

KEY_WOW64_64KEY

KEY_WOW64_32KEY

값 형

REG_BINARY

REG_DWORD

REG_DWORD_LITTLE_ENDIAN

REG_DWORD_BIG_ENDIAN

REG_EXPAND_SZ

REG_LINK

REG_MULTI_SZ

REG_NONE

REG_QWORD

REG_QWORD_LITTLE_ENDIAN

REG_RESOURCE_LIST

REG_FULL_RESOURCE_DESCRIPTOR

REG_RESOURCE_REQUIREMENTS_LIST

REG_SZ

레지스트리 핸들 객체

Close()

Detach()

__enter__()

__exit__()

winsound — Sound-playing interface for Windows

Beep()

PlaySound()

MessageBeep()

SND_FILENAME

SND_ALIAS

SND_LOOP

SND_MEMORY

SND_PURGE

SND_ASYNC

SND_NODEFAULT

SND_NOSTOP

SND_NOWAIT

MB_ICONASTERISK

MB_ICONEXCLAMATION

MB_ICONHAND

MB_ICONQUESTION

MB_OK

유닉스 특정 서비스

posix — The most common POSIX system calls

대용량 파일 지원

주목할만한 모듈 내용

environ

pwd — The password database

getpwuid()

getpwnam()

getpwall()

grp — The group database

getgrgid()

getgrnam()

getgrall()

termios — POSIX style tty control

tcgetattr()

tcsetattr()

TCSANOW

TCSADRAIN

TCSAFLUSH

tcsendbreak()

tcdrain()

tcflush()

tcflow()

tcgetwinsize()

tcsetwinsize()

예제

tty — Terminal control functions

cfmakeraw()

cfmakecbreak()

setraw()

setcbreak()

pty — Pseudo-terminal utilities

fork()

openpty()

spawn()

예제

fcntl — The fcntl and ioctl system calls

fcntl()

ioctl()

flock()

lockf()

LOCK_UN

LOCK_SH

LOCK_EX

LOCK_NB

resource — Resource usage information

error

자원 제한

RLIM_INFINITY

getrlimit()

setrlimit()

prlimit()

RLIMIT_CORE

RLIMIT_CPU

RLIMIT_FSIZE

RLIMIT_DATA

RLIMIT_STACK

RLIMIT_RSS

RLIMIT_NPROC

RLIMIT_NOFILE

RLIMIT_OFILE

RLIMIT_MEMLOCK

RLIMIT_VMEM

RLIMIT_AS

RLIMIT_MSGQUEUE

RLIMIT_NICE

RLIMIT_RTPRIO

RLIMIT_RTTIME

RLIMIT_SIGPENDING

RLIMIT_SBSIZE

RLIMIT_SWAP

RLIMIT_NPTS

RLIMIT_KQUEUES

자원 사용량

getrusage()

getpagesize()

RUSAGE_SELF

RUSAGE_CHILDREN

RUSAGE_BOTH

RUSAGE_THREAD

syslog — Unix syslog library routines

syslog()

openlog()

closelog()

setlogmask()

LOG_EMERG

LOG_ALERT

LOG_CRIT

LOG_ERR

LOG_WARNING

LOG_NOTICE

LOG_INFO

LOG_DEBUG

LOG_AUTH

LOG_AUTHPRIV

LOG_CRON

LOG_DAEMON

LOG_FTP

LOG_INSTALL

LOG_KERN

LOG_LAUNCHD

LOG_LPR

LOG_MAIL

LOG_NETINFO

LOG_NEWS

LOG_RAS

LOG_REMOTEAUTH

LOG_SYSLOG

LOG_USER

LOG_UUCP

LOG_LOCAL0

LOG_LOCAL1

LOG_LOCAL2

LOG_LOCAL3

LOG_LOCAL4

LOG_LOCAL5

LOG_LOCAL6

LOG_LOCAL7

LOG_PID

LOG_CONS

LOG_NDELAY

LOG_ODELAY

LOG_NOWAIT

LOG_PERROR

예제

간단한 예제

Modules command-line interface (CLI)

대체된 모듈

getopt — C-style parser for command line options

getopt()

gnu_getopt()

GetoptError

error

optparse — Parser for command line options

배경

용어

옵션은 무엇을 위한 것입니까?

위치 인자는 무엇을 위한 것입니까?

자습서

옵션 액션의 이해

store 액션

불리언 (플래그) 옵션 처리하기

다른 액션들

기본값

도움말 생성하기

옵션 그룹화하기

OptionGroup

get_option_group()

버전 문자열 인쇄하기

print_version()

get_version()

optparse가 에러를 처리하는 방법

모두 합치기

레퍼런스 지침서

구문 분석기 만들기

OptionParser

구문 분석기 채우기

옵션 정의하기

add_option()

Values

옵션 어트리뷰트

Option

action

type

dest

default

nargs

const

choices

callback

callback_args

callback_kwargs

help

metavar

표준 옵션 액션

표준 옵션 형

인자 구문 분석하기

parse_args()

옵션 구문 분석기를 조회하고 조작하기

disable_interspersed_args()

enable_interspersed_args()

get_option()

has_option()

remove_option()

옵션 간의 충돌

정리

기타 메서드

set_usage()

print_usage()

get_usage()

set_defaults()

옵션 콜백

콜백 옵션 정의하기

콜백이 호출되는 방법

콜백에서 에러 발생시키기

콜백 예제 1: 간단한 콜백

콜백 예제 2: 옵션 순서 확인

콜백 예제 3: 옵션 순서 확인 (일반화)

콜백 예제 4: 임의 조건 확인

콜백 예제 5: 고정 인자

콜백 예제 6: 가변 인자

optparse 확장하기

새로운 형 추가하기

TYPES

TYPE_CHECKER

새로운 액션 추가하기

ACTIONS

STORE_ACTIONS

TYPED_ACTIONS

ALWAYS_TYPED_ACTIONS

Exceptions

OptionError

OptionConflictError

OptionValueError

BadOptionError

AmbiguousOptionError

Removed Modules

Security Considerations

파이썬 인터프리터 확장 및 내장

권장 제삼자 도구

제삼자 도구 없이 확장 만들기

1. C나 C++로 파이썬 확장하기

1.1. 간단한 예

1.2. 막간극: 에러와 예외

1.3. 예제로 돌아가기

1.4. 모듈의 메서드 테이블과 초기화 함수

1.5. 컴파일과 링크

1.6. C에서 파이썬 함수 호출하기

1.7. 확장 함수에서 매개 변수 추출하기

1.8. 확장 함수를 위한 키워드 매개 변수

1.9. 임의의 값을 구축하기

1.10. 참조 횟수

1.10.1. 파이썬에서 참조 횟수 세기

1.10.2. 소유권 규칙

1.10.3. 살얼음

1.10.4. NULL 포인터

1.11. C++로 확장 작성하기

1.12. 확장 모듈을 위한 C API 제공하기

2. 확장형 정의하기: 자습서

2.1. 기초

2.2. 기초 예제에 데이터와 메서드 추가하기

2.3. 데이터 어트리뷰트를 더 세밀하게 제어하기

2.4. 순환 가비지 수거 지원하기

2.5. 다른 형의 서브 클래싱

3. 확장형 정의하기: 여러 가지 주제

3.1. 파이널리제이션과 할당 해제

3.2. 객체 표현

3.3. 어트리뷰트 관리

3.3.1. 범용 어트리뷰트 관리

3.3.2. 형별 어트리뷰트 관리

3.4. 객체 비교

3.5. 추상 프로토콜 지원

3.6. 약한 참조 지원

3.7. 추가 제안

4. C와 C++ 확장 빌드하기

4.1. Building C and C++ Extensions with setuptools

5. 윈도우에서 C와 C++ 확장 빌드하기

5.1. 요리책 접근법

5.2. 유닉스와 윈도우의 차이점

5.3. DLL을 실제로 사용하기

더 큰 응용 프로그램에 CPython 런타임을 내장하기

1. 다른 응용 프로그램에 파이썬 내장하기

1.1. 매우 고수준의 내장

1.2. 매우 고수준 내장을 넘어서: 개요

1.3. 순수한 내장

1.4. 내장된 파이썬을 확장하기

1.5. C++로 파이썬 내장하기

1.6. 유닉스 계열 시스템에서 컴파일과 링크하기

파이썬/C API 레퍼런스 설명서

소개

코딩 표준

인클루드 파일

유용한 매크로들

객체, 형 그리고 참조 횟수

참조 횟수

참조 횟수 상세

형

예외

파이썬 임베딩하기

디버깅 빌드

C API Stability

Unstable C API

안정적인 응용 프로그램 바이너리 인터페이스

Limited C API

Stable ABI

Limited API Scope and Performance

Limited API Caveats

Platform Considerations

Contents of Limited API

매우 고수준 계층

참조 횟수

예외 처리

인쇄와 지우기

예외 발생시키기

경고 발행하기

에러 표시기 조회하기

시그널 처리하기

예외 클래스

예외 객체

유니코드 예외 객체

재귀 제어

표준 예외

표준 경고 범주

유틸리티

운영 체제 유틸리티

시스템 함수

프로세스 제어

모듈 임포트 하기

데이터 마샬링 지원

인자 구문 분석과 값 구축

인자 구문 분석

문자열과 버퍼

숫자

기타 객체

API 함수

값 구축

문자열 변환과 포매팅

PyHash API

리플렉션

코덱 등록소와 지원 함수

코덱 조회 API

유니코드 인코딩 에러 처리기용 등록소 API

PyTime C API

Types

Clock Functions

Raw Clock Functions

Conversion functions

Support for Perf Maps

추상 객체 계층

객체 프로토콜

호출 프로토콜

tp_call 프로토콜

벡터콜(Vectorcall) 프로토콜

재귀 제어

벡터콜 지원 API

객체 호출 API

호출 지원 API

숫자 프로토콜

시퀀스 프로토콜

매핑 프로토콜

이터레이터 프로토콜

버퍼 프로토콜

버퍼 구조체

버퍼 요청 유형

요청 독립적 필드

readonly, format

shape, strides, suboffsets

연속성 요청

복합 요청

복잡한 배열

NumPy-스타일: shape과 strides

PIL-스타일: shape, strides 및 suboffsets

버퍼 관련 함수

구상 객체 계층

기본 객체

형 객체

힙에 할당된 형 만들기

None 객체

숫자 객체

정수 객체

불리언 객체

Floating-Point Objects

Pack and Unpack functions

Pack functions

Unpack functions

복소수 객체

C 구조체로서의 복소수

파이썬 객체로서의 복소수

시퀀스 객체

바이트열 객체

바이트 배열 객체

형 검사 매크로

직접 API 함수

매크로

유니코드 객체와 코덱

유니코드 객체

유니코드 형

유니코드 문자 속성

유니코드 문자열 생성과 액세스

로케일 인코딩

파일 시스템 인코딩

wchar_t 지원

내장 코덱

일반 코덱

UTF-8 코덱

UTF-32 코덱

UTF-16 코덱

UTF-7 코덱

유니코드 이스케이프 코덱

원시 유니코드 이스케이프 코덱

Latin-1 코덱

ASCII 코덱

문자 맵 코덱

윈도우 용 MBCS 코덱

메서드와 슬롯

메서드와 슬롯 함수

PyUnicodeWriter

튜플 객체

구조체 시퀀스 객체

리스트 객체

컨테이너 객체

딕셔너리 객체

집합 객체

함수 객체

함수 객체

인스턴스 메서드 객체

메서드 객체

셀 객체

코드 객체

Extra information

기타 객체

파일 객체

모듈 객체

C 모듈 초기화

단단계 초기화

다단계 초기화

저수준 모듈 생성 함수

지원 함수

모듈 조회

이터레이터 객체

디스크립터 객체

슬라이스 객체

Ellipsis 객체

MemoryView 객체

약한 참조 객체

캡슐

Frame Objects

Internal Frames

제너레이터 객체

코루틴 객체

컨텍스트 변수 객체

DateTime 객체

Objects for Type Hinting

초기화, 파이널리제이션 및 스레드

파이썬 초기화 전

전역 구성 변수

인터프리터 초기화와 파이널리제이션

프로세스 전체 매개 변수

스레드 상태와 전역 인터프리터 록

확장 코드에서 GIL 해제하기

파이썬이 만들지 않은 스레드

fork()에 대한 주의 사항

Cautions regarding runtime finalization

고수준 API

저수준 API

서브 인터프리터 지원

A Per-Interpreter GIL

버그와 주의 사항

비동기 알림

프로파일링과 추적

Reference tracing

고급 디버거 지원

스레드 로컬 저장소 지원

스레드별 저장소 (TSS - Thread Specific Storage) API

동적 할당

메서드

스레드 로컬 저장소 (TLS) API

Synchronization Primitives

Python Critical Section API

파이썬 초기화 구성

PyConfig C API

Example

PyWideStringList

PyStatus

PyPreConfig

Preinitialize Python with PyPreConfig

PyConfig

PyConfig를 사용한 초기화

격리된 구성

파이썬 구성

Python Path Configuration

PyInitConfig C API

Create Config

Error Handling

Get Options

Set Options

Module

Initialize Python

Example

Runtime Python configuration API

Py_GetArgcArgv()

다단계 초기화 비공개 잠정적 API

메모리 관리

개요

Allocator Domains

원시 메모리 인터페이스

메모리 인터페이스

객체 할당자

기본 메모리 할당자

메모리 할당자 사용자 정의

Debug hooks on the Python memory allocators

pymalloc 할당자

pymalloc 아레나 할당자 사용자 정의

The mimalloc allocator

tracemalloc C API

예

객체 구현 지원

힙에 객체 할당하기

공통 객체 구조체

기본 객체 형과 매크로

함수와 메서드 구현

확장형의 어트리뷰트 액세스

Member flags

Member types

Defining Getters and Setters

형 객체

간략 참조

“tp 슬롯”

서브 슬롯

슬롯 typedef

PyTypeObject 정의

PyObject 슬롯

PyVarObject 슬롯

PyTypeObject 슬롯

Static Types

힙 형

숫자 객체 구조체

매핑 객체 구조체

시퀀스 객체 구조체

버퍼 객체 구조체

비동기 객체 구조체

슬롯 형 typedef

예

순환 가비지 수집 지원

Controlling the Garbage Collector State

Querying Garbage Collector State

API와 ABI 버전 붙이기

Monitoring C API

Generating Execution Events

Managing the Monitoring State

파이썬 모듈 설치하기

핵심 용어

기본 사용법

어떻게 …?

… 파이썬 3.4 이전 버전의 파이썬에서 pip 를 설치합니까?

… 현재 사용자만을 위해 패키지를 설치합니까?

… 과학 계산용 파이썬 패키지를 설치합니까?

… 병렬로 설치된 여러 버전의 파이썬으로 작업합니까?

흔히 만나는 설치 문제

리눅스에 시스템 파이썬 설치하기

Pip가 설치되지 않았습니다.

바이너리 확장 설치하기

파이썬 HOWTO

파이썬 자주 나오는 질문들

일반적인 파이썬 FAQ

일반적인 정보

현실 속의 파이썬

프로그래밍 FAQ

일반적인 질문

핵심 언어

숫자와 문자열

성능

시퀀스 (튜플/리스트)

객체

모듈

설계와 역사 FAQ

파이썬은 왜 문장의 그룹화에 들여쓰기를 사용합니까?

간단한 산술 연산으로 이상한 결과가 나오는 이유는 무엇입니까?

부동 소수점 계산이 왜 그렇게 부정확합니까?

파이썬 문자열이 불변인 이유는 무엇입니까?

메서드 정의와 호출에서 ‘self’를 명시적으로 사용해야 하는 이유는 무엇입니까?

표현식에서 대입을 사용할 수 없는 이유는 무엇입니까?

파이썬은 왜 일부 기능(예를 들어 list.index())에는 메서드를 사용하고 다른 기능(예를 들어 len(list))에는 함수를 사용합니까?

join()이 리스트나 튜플 메서드가 아니라 문자열 메서드인 이유는 무엇입니까?

예외는 얼마나 빠릅니까?

파이썬에 switch 나 case 문이 없는 이유는 무엇입니까?

OS별 스레드 구현에 의존하는 대신 인터프리터에서 스레드를 에뮬레이션할 수 없습니까?

람다 표현식이 문장을 포함할 수 없는 이유는 무엇입니까?

파이썬을 기계 코드, C 또는 다른 언어로 컴파일 할 수 있습니까?

파이썬은 메모리를 어떻게 관리합니까?

CPython이 더 전통적인 가비지 수거 체계를 사용하지 않는 이유는 무엇입니까?

CPython이 종료될 때 모든 메모리가 해제되지 않는 이유는 무엇입니까?

별도의 튜플과 리스트 데이터형이 있는 이유는 무엇입니까?

CPython에서 리스트는 어떻게 구현됩니까?

CPython에서 딕셔너리는 어떻게 구현됩니까?

딕셔너리 키가 불변이어야 하는 이유는 무엇입니까?

list.sort()가 정렬된 리스트를 반환하지 않는 이유는 무엇입니까?

파이썬에서 인터페이스 명세를 어떻게 지정하고 강제합니까?

goto가 없는 이유는 무엇입니까?

날 문자열(r-strings)이 역 슬래시로 끝날 수 없는 이유는 무엇입니까?

왜 파이썬에는 어트리뷰트 대입을 위한 “with” 문이 없습니까?

Why don’t generators support the with statement?

if/while/def/class 문에 콜론이 필요한 이유는 무엇입니까?

파이썬은 왜 리스트와 튜플 끝에 쉼표를 허용합니까?

라이브러리와 확장 FAQ

일반 라이브러리 관련 질문

일반적인 작업

스레드

입력과 출력

네트워크/인터넷 프로그래밍

데이터베이스

수학과 숫자

확장/내장 FAQ

C로 나만의 함수를 만들 수 있습니까?

C++로 나만의 함수를 만들 수 있습니까?

C를 쓰는 것은 어렵습니다; 대안이 있습니까?

C에서 임의의 파이썬 문장을 어떻게 실행할 수 있습니까?

C에서 임의의 파이썬 표현식을 어떻게 평가할 수 있습니까?

파이썬 객체에서 C값을 어떻게 추출합니까?

Py_BuildValue()를 사용하여 임의 길이의 튜플을 만드는 방법은 무엇입니까?

C에서 객체의 메서드를 어떻게 호출합니까?

PyErr_Print()의 출력(또는 stdout/stderr로 인쇄되는 모든 것)을 어떻게 잡습니까?

C에서 파이썬으로 작성된 모듈에 어떻게 액세스합니까?

파이썬에서 C++ 객체에 어떻게 인터페이스 합니까?

Setup 파일을 사용하여 모듈을 추가했는데 make가 실패합니다; 왜 그렇습니까?

확장을 어떻게 디버깅합니까?

리눅스 시스템에서 파이썬 모듈을 컴파일하고 싶지만, 일부 파일이 없습니다. 왜 그렇습니까?

“잘못된 입력”과 “불완전한 입력”을 어떻게 구별할 수 있습니까?

정의되지 않은 g++ 기호 __builtin_new나 __pure_virtual을 어떻게 찾을 수 있습니까?

일부 메서드는 C로 구현되고 그 밖의 것은 파이썬으로 구현된 (예를 들어 상속을 통해) 객체 클래스를 만들 수 있습니까?

윈도우 파이썬 FAQ

윈도우에서 파이썬 프로그램을 실행하려면 어떻게 해야 합니까?

파이썬 스크립트 실행 파일로 만들려면 어떻게 해야 합니까?

왜 때때로 파이썬은 시작하는 데 시간이 오래 걸립니까?

파이썬 스크립트에서 실행 파일을 만드는 방법은 무엇입니까?

*.pyd 파일은 DLL과 동일합니까?

윈도우 응용프로그램에 파이썬을 포함하려면 어떻게 해야 합니까?

편집기가 내 파이썬 소스에 탭을 삽입하지 않도록 하려면 어떻게 해야 합니까?

블로킹 없이 키 입력을 확인하려면 어떻게 해야 합니까?

How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?

그래픽 사용자 인터페이스 FAQ

일반적인 GUI 질문

What GUI toolkits exist for Python?

Tkinter 질문

“왜 내 컴퓨터에 파이썬이 설치되어 있습니까?” FAQ

파이썬이 무엇입니까?

내 컴퓨터에 파이썬이 설치된 이유는 무엇입니까?

파이썬을 삭제할 수 있습니까?

Deprecations

Pending removal in Python 3.15

Pending removal in Python 3.16

Pending removal in future versions

C API deprecations

Pending removal in Python 3.15

Pending removal in future versions

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역사와 라이센스

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포함된 소프트웨어에 대한 라이센스 및 승인

메르센 트위스터

소켓

비동기 소켓 서비스

쿠키 관리

실행 추적

UUencode 및 UUdecode 함수

XML 원격 프로시저 호출

test_epoll

Select kqueue

SipHash24

strtod 와 dtoa

OpenSSL

expat

libffi

zlib

cfuhash

libmpdec

W3C C14N 테스트 스위트

mimalloc

asyncio

Global Unbounded Sequences (GUS)

파이썬의 새로운 기능

“파이썬의 새로운 기능” 수필 시리즈는 주요 파이썬 버전 간의 가장 중요한 변화를 둘러 봅니다. 새로운 릴리스 이후에 최신 상태를 유지하고자 하는 사람들에게는 “꼭 읽어야 할” 문서입니다.

What’s new in Python 3.14

Summary – release highlights

New features

Other language changes

New modules

Improved modules

Optimizations

Deprecated

Removed

Porting to Python 3.14

Build changes

C API changes

What’s New In Python 3.13

Summary – Release Highlights

New Features

Other Language Changes

New Modules

Improved Modules

Optimizations

Removed Modules And APIs

New Deprecations

CPython Bytecode Changes

C API Changes

Build Changes

Porting to Python 3.13

Regression Test Changes

What’s New In Python 3.12

Summary – Release highlights

New Features

New Features Related to Type Hints

Other Language Changes

New Modules

Improved Modules

Optimizations

CPython bytecode changes

Demos and Tools

Deprecated

Removed

Porting to Python 3.12

Build Changes

C API Changes

What’s New In Python 3.11

Summary – Release highlights

New Features

New Features Related to Type Hints

Other Language Changes

Other CPython Implementation Changes

New Modules

Improved Modules

Optimizations

Faster CPython

CPython bytecode changes

Deprecated

Pending Removal in Python 3.12

Removed

Porting to Python 3.11

Build Changes

C API Changes

Notable changes in 3.11.4

Notable changes in 3.11.5

What’s New In Python 3.10

Summary – Release highlights

New Features

New Features Related to Type Hints

Other Language Changes

New Modules

Improved Modules

Optimizations

Deprecated

Removed

Porting to Python 3.10

CPython bytecode changes

Build Changes

C API Changes

Notable security feature in 3.10.7

Notable security feature in 3.10.8

Notable changes in 3.10.12

파이썬 3.9의 새로운 기능

요약 – 배포 주요 사항

여러분의 코드에서 DeprecationWarning을 확인해야합니다

새로운 기능

기타 언어 변경

새 모듈

개선된 모듈

최적화

폐지

제거

파이썬 3.9로 이식하기

빌드 변경

C API 변경

파이썬 3.9.1의 주목할만한 변경 사항

파이썬 3.9.2의 주목할만한 변경 사항

파이썬 3.9.3의 주목할만한 변경 사항

Notable changes in Python 3.9.5

Notable security feature in 3.9.14

Notable changes in 3.9.17

파이썬 3.8의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

기타 언어 변경

새 모듈

개선된 모듈

최적화

빌드와 C API 변경

폐지

API 및 기능 제거

파이썬 3.8로 이식하기

파이썬 3.8.1의 주목할만한 변경 사항

Notable changes in Python 3.8.2

Notable changes in Python 3.8.3

파이썬 3.8.8의 주목할만한 변경 사항

Notable changes in Python 3.8.9

Notable changes in Python 3.8.10

Notable changes in Python 3.8.10

Notable changes in Python 3.8.12

Notable security feature in 3.8.14

Notable changes in 3.8.17

파이썬 3.7의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

기타 언어 변경

새 모듈

개선된 모듈

C API 변경

빌드 변경

최적화

기타 CPython 구현 변경

폐지된 파이썬 동작

폐지된 파이썬 모듈, 함수 및 메서드

폐지된 C API의 함수 및 형

플랫폼 지원 제거

API 및 기능 제거

모듈 제거

윈도우 전용 변경

파이썬 3.7로 이식하기

파이썬 3.7.1의 주목할만한 변경 사항

파이썬 3.7.2의 주목할만한 변경 사항

파이썬 3.7.6의 주목할만한 변경 사항

파이썬 3.7.10의 주목할만한 변경 사항

Notable changes in Python 3.7.11

Notable security feature in 3.7.14

파이썬 3.6의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

기타 언어 변경

새로운 모듈

개선된 모듈

최적화

빌드와 C API 변경

기타 개선 사항

폐지

제거

파이썬 3.6으로 이식하기

파이썬 3.6.2의 주목할만한 변경 사항

파이썬 3.6.4의 주목할만한 변경 사항

파이썬 3.6.5의 주목할만한 변경 사항

파이썬 3.6.7의 주목할만한 변경 사항

파이썬 3.6.10의 주목할만한 변경 사항

파이썬 3.6.13의 주목할만한 변경 사항

Notable changes in Python 3.6.14

파이썬 3.5의 새로운 기능

요약 – 배포 주요 사항

새로운 기능

기타 언어 변경

새로운 모듈

개선된 모듈

기타 모듈 수준 변경

최적화

빌드와 C API 변경

폐지

제거

파이썬 3.5로 이식하기

파이썬 3.5.4의 주목할만한 변경 사항

What’s New In Python 3.4

Summary – Release Highlights

New Features

New Modules

Improved Modules

CPython Implementation Changes

Deprecated

Removed

Porting to Python 3.4

Changed in 3.4.3

What’s New In Python 3.3

Summary – Release highlights

PEP 405: Virtual Environments

PEP 420: Implicit Namespace Packages

PEP 3118: New memoryview implementation and buffer protocol documentation

PEP 393: Flexible String Representation

PEP 397: Python Launcher for Windows

PEP 3151: Reworking the OS and IO exception hierarchy

PEP 380: Syntax for Delegating to a Subgenerator

PEP 409: Suppressing exception context

PEP 414: Explicit Unicode literals

PEP 3155: Qualified name for classes and functions

PEP 412: Key-Sharing Dictionary

PEP 362: Function Signature Object

PEP 421: Adding sys.implementation

Using importlib as the Implementation of Import

Other Language Changes

A Finer-Grained Import Lock

Builtin functions and types

New Modules

Improved Modules

Optimizations

Build and C API Changes

Deprecated

Porting to Python 3.3

What’s New In Python 3.2

PEP 384: Defining a Stable ABI

PEP 389: Argparse Command Line Parsing Module

PEP 391: Dictionary Based Configuration for Logging

PEP 3148: The concurrent.futures module

PEP 3147: PYC Repository Directories

PEP 3149: ABI Version Tagged .so Files

PEP 3333: Python Web Server Gateway Interface v1.0.1

Other Language Changes

New, Improved, and Deprecated Modules

Multi-threading

Optimizations

Unicode

Codecs

Documentation

IDLE

Code Repository

Build and C API Changes

Porting to Python 3.2

What’s New In Python 3.1

PEP 372: Ordered Dictionaries

PEP 378: Format Specifier for Thousands Separator

Other Language Changes

New, Improved, and Deprecated Modules

Optimizations

IDLE

Build and C API Changes

Porting to Python 3.1

What’s New In Python 3.0

Common Stumbling Blocks

Overview Of Syntax Changes

Changes Already Present In Python 2.6

Library Changes

PEP 3101: A New Approach To String Formatting

Changes To Exceptions

Miscellaneous Other Changes

Build and C API Changes

Performance

Porting To Python 3.0

What’s New in Python 2.7

The Future for Python 2.x

Changes to the Handling of Deprecation Warnings

Python 3.1 Features

PEP 372: Adding an Ordered Dictionary to collections

PEP 378: Format Specifier for Thousands Separator

PEP 389: The argparse Module for Parsing Command Lines

PEP 391: Dictionary-Based Configuration For Logging

PEP 3106: Dictionary Views

PEP 3137: The memoryview Object

Other Language Changes

New and Improved Modules

Build and C API Changes

Other Changes and Fixes

Porting to Python 2.7

New Features Added to Python 2.7 Maintenance Releases

Acknowledgements

What’s New in Python 2.6

Python 3.0

Changes to the Development Process

PEP 343: The ‘with’ statement

PEP 366: Explicit Relative Imports From a Main Module

PEP 370: Per-user site-packages Directory

PEP 371: The multiprocessing Package

PEP 3101: Advanced String Formatting

PEP 3105: print As a Function

PEP 3110: Exception-Handling Changes

PEP 3112: Byte Literals

PEP 3116: New I/O Library

PEP 3118: Revised Buffer Protocol

PEP 3119: Abstract Base Classes

PEP 3127: Integer Literal Support and Syntax

PEP 3129: Class Decorators

PEP 3141: A Type Hierarchy for Numbers

Other Language Changes

New and Improved Modules

Deprecations and Removals

Build and C API Changes

Porting to Python 2.6

Acknowledgements

What’s New in Python 2.5

PEP 308: Conditional Expressions

PEP 309: Partial Function Application

PEP 314: Metadata for Python Software Packages v1.1

PEP 328: Absolute and Relative Imports

PEP 338: Executing Modules as Scripts

PEP 341: Unified try/except/finally

PEP 342: New Generator Features

PEP 343: The ‘with’ statement

PEP 352: Exceptions as New-Style Classes

PEP 353: Using ssize_t as the index type

PEP 357: The ‘__index__’ method

Other Language Changes

New, Improved, and Removed Modules

Build and C API Changes

Porting to Python 2.5

Acknowledgements

What’s New in Python 2.4

PEP 218: Built-In Set Objects

PEP 237: Unifying Long Integers and Integers

PEP 289: Generator Expressions

PEP 292: Simpler String Substitutions

PEP 318: Decorators for Functions and Methods

PEP 322: Reverse Iteration

PEP 324: New subprocess Module

PEP 327: Decimal Data Type

PEP 328: Multi-line Imports

PEP 331: Locale-Independent Float/String Conversions

Other Language Changes

New, Improved, and Deprecated Modules

Build and C API Changes

Porting to Python 2.4

Acknowledgements

What’s New in Python 2.3

PEP 218: A Standard Set Datatype

PEP 255: Simple Generators

PEP 263: Source Code Encodings

PEP 273: Importing Modules from ZIP Archives

PEP 277: Unicode file name support for Windows NT

PEP 278: Universal Newline Support

PEP 279: enumerate()

PEP 282: The logging Package

PEP 285: A Boolean Type

PEP 293: Codec Error Handling Callbacks

PEP 301: Package Index and Metadata for Distutils

PEP 302: New Import Hooks

PEP 305: Comma-separated Files

PEP 307: Pickle Enhancements

Extended Slices

Other Language Changes

New, Improved, and Deprecated Modules

Pymalloc: A Specialized Object Allocator

Build and C API Changes

Other Changes and Fixes

Porting to Python 2.3

Acknowledgements

What’s New in Python 2.2

Introduction

PEPs 252 and 253: Type and Class Changes

PEP 234: Iterators

PEP 255: Simple Generators

PEP 237: Unifying Long Integers and Integers

PEP 238: Changing the Division Operator

Unicode Changes

PEP 227: Nested Scopes

New and Improved Modules

Interpreter Changes and Fixes

Other Changes and Fixes

Acknowledgements

What’s New in Python 2.1

Introduction

PEP 227: Nested Scopes

PEP 236: __future__ Directives

PEP 207: Rich Comparisons

PEP 230: Warning Framework

PEP 229: New Build System

PEP 205: Weak References

PEP 232: Function Attributes

PEP 235: Importing Modules on Case-Insensitive Platforms

PEP 217: Interactive Display Hook

PEP 208: New Coercion Model

PEP 241: Metadata in Python Packages

New and Improved Modules

Other Changes and Fixes

Acknowledgements

What’s New in Python 2.0

Introduction

What About Python 1.6?

New Development Process

Unicode

List Comprehensions

Augmented Assignment

String Methods

Garbage Collection of Cycles

Other Core Changes

Porting to 2.0

Extending/Embedding Changes

Distutils: Making Modules Easy to Install

XML Modules

Module changes

New modules

IDLE Improvements

Deleted and Deprecated Modules

Acknowledgements

The “Changelog” is an HTML version of the file built [https://pypi.org/project/blurb/] from the contents of the Misc/NEWS.d [https://github.com/python/cpython/tree/main/Misc/NEWS.d] directory tree, which contains all nontrivial changes to Python for the current version.

Changelog

Python next

Python 3.14.0 alpha 2

Python 3.14.0 alpha 1

Python 3.13.0 beta 1

Python 3.13.0 alpha 6

Python 3.13.0 alpha 5

Python 3.13.0 alpha 4

Python 3.13.0 alpha 3

Python 3.13.0 alpha 2

Python 3.13.0 alpha 1

Python 3.12.0 beta 1

Python 3.12.0 alpha 7

Python 3.12.0 alpha 6

Python 3.12.0 alpha 5

Python 3.12.0 alpha 4

Python 3.12.0 alpha 3

Python 3.12.0 alpha 2

Python 3.12.0 alpha 1

Python 3.11.0 beta 1

Python 3.11.0 alpha 7

Python 3.11.0 alpha 6

Python 3.11.0 alpha 5

Python 3.11.0 alpha 4

Python 3.11.0 alpha 3

Python 3.11.0 alpha 2

Python 3.11.0 alpha 1

Python 3.10.0 beta 1

Python 3.10.0 alpha 7

Python 3.10.0 alpha 6

Python 3.10.0 alpha 5

Python 3.10.0 alpha 4

Python 3.10.0 alpha 3

Python 3.10.0 alpha 2

Python 3.10.0 alpha 1

Python 3.9.0 beta 1

Python 3.9.0 alpha 6

Python 3.9.0 alpha 5

Python 3.9.0 alpha 4

Python 3.9.0 alpha 3

Python 3.9.0 alpha 2

Python 3.9.0 alpha 1

Python 3.8.0 beta 1

Python 3.8.0 alpha 4

Python 3.8.0 alpha 3

Python 3.8.0 alpha 2

Python 3.8.0 alpha 1

Python 3.7.0 final

Python 3.7.0 release candidate 1

Python 3.7.0 beta 5

Python 3.7.0 beta 4

Python 3.7.0 beta 3

Python 3.7.0 beta 2

Python 3.7.0 beta 1

Python 3.7.0 alpha 4

Python 3.7.0 alpha 3

Python 3.7.0 alpha 2

Python 3.7.0 alpha 1

Python 3.6.6 final

Python 3.6.6 release candidate 1

Python 3.6.5 final

Python 3.6.5 release candidate 1

Python 3.6.4 final

Python 3.6.4 release candidate 1

Python 3.6.3 final

Python 3.6.3 release candidate 1

Python 3.6.2 final

Python 3.6.2 release candidate 2

Python 3.6.2 release candidate 1

Python 3.6.1 final

Python 3.6.1 release candidate 1

Python 3.6.0 final

Python 3.6.0 release candidate 2

Python 3.6.0 release candidate 1

Python 3.6.0 beta 4

Python 3.6.0 beta 3

Python 3.6.0 beta 2

Python 3.6.0 beta 1

Python 3.6.0 alpha 4

Python 3.6.0 alpha 3

Python 3.6.0 alpha 2

Python 3.6.0 alpha 1

Python 3.5.5 final

Python 3.5.5 release candidate 1

Python 3.5.4 final

Python 3.5.4 release candidate 1

Python 3.5.3 final

Python 3.5.3 release candidate 1

Python 3.5.2 final

Python 3.5.2 release candidate 1

Python 3.5.1 final

Python 3.5.1 release candidate 1

Python 3.5.0 final

Python 3.5.0 release candidate 4

Python 3.5.0 release candidate 3

Python 3.5.0 release candidate 2

Python 3.5.0 release candidate 1

Python 3.5.0 beta 4

Python 3.5.0 beta 3

Python 3.5.0 beta 2

Python 3.5.0 beta 1

Python 3.5.0 alpha 4

Python 3.5.0 alpha 3

Python 3.5.0 alpha 2

Python 3.5.0 alpha 1

What’s new in Python 3.14

Editor:

TBD

This article explains the new features in Python 3.14, compared to 3.13.

For full details, see the changelog.

참고

Prerelease users should be aware that this document is currently in draft form. It will be updated substantially as Python 3.14 moves towards release, so it’s worth checking back even after reading earlier versions.

Summary – release highlights

PEP 649: deferred evaluation of annotations

PEP 741: Python Configuration C API

New features

PEP 649: deferred evaluation of annotations

The annotations on functions, classes, and modules are no longer evaluated eagerly. Instead, annotations are stored in special-purpose annotate functions and evaluated only when necessary. This is specified in PEP 649 [https://peps.python.org/pep-0649/] and PEP 749 [https://peps.python.org/pep-0749/].

This change is designed to make annotations in Python more performant and more usable in most circumstances. The runtime cost for defining annotations is minimized, but it remains possible to introspect annotations at runtime. It is usually no longer necessary to enclose annotations in strings if they contain forward references.

The new annotationlib module provides tools for inspecting deferred annotations. Annotations may be evaluated in the VALUE format (which evaluates annotations to runtime values, similar to the behavior in earlier Python versions), the FORWARDREF format (which replaces undefined names with special markers), and the STRING format (which returns annotations as strings).

This example shows how these formats behave:

>>> from annotationlib import get_annotations, Format
>>> def func(arg: Undefined):
...     pass
>>> get_annotations(func, format=Format.VALUE)
Traceback (most recent call last):
  ...
NameError: name 'Undefined' is not defined
>>> get_annotations(func, format=Format.FORWARDREF)
{'arg': ForwardRef('Undefined')}
>>> get_annotations(func, format=Format.STRING)
{'arg': 'Undefined'}

Implications for annotated code

If you define annotations in your code (for example, for use with a static type checker), then this change probably does not affect you: you can keep writing annotations the same way you did with previous versions of Python.

You will likely be able to remove quoted strings in annotations, which are frequently used for forward references. Similarly, if you use from __future__ import annotations to avoid having to write strings in annotations, you may well be able to remove that import. However, if you rely on third-party libraries that read annotations, those libraries may need changes to support unquoted annotations before they work as expected.

Implications for readers of __annotations__

If your code reads the __annotations__ attribute on objects, you may want to make changes in order to support code that relies on deferred evaluation of annotations. For example, you may want to use annotationlib.get_annotations() with the FORWARDREF format, as the dataclasses module now does.

Related changes

The changes in Python 3.14 are designed to rework how __annotations__ works at runtime while minimizing breakage to code that contains annotations in source code and to code that reads __annotations__. However, if you rely on undocumented details of the annotation behavior or on private functions in the standard library, there are many ways in which your code may not work in Python 3.14. To safeguard your code against future changes, use only the documented functionality of the annotationlib module.

from __future__ import annotations

In Python 3.7, PEP 563 [https://peps.python.org/pep-0563/] introduced the from __future__ import annotations directive, which turns all annotations into strings. This directive is now considered deprecated and it is expected to be removed in a future version of Python. However, this removal will not happen until after Python 3.13, the last version of Python without deferred evaluation of annotations, reaches its end of life in 2029. In Python 3.14, the behavior of code using from __future__ import annotations is unchanged.

Improved error messages

When unpacking assignment fails due to incorrect number of variables, the error message prints the received number of values in more cases than before. (Contributed by Tushar Sadhwani in gh-122239 [https://github.com/python/cpython/issues/122239].)

>>> x, y, z = 1, 2, 3, 4
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    x, y, z = 1, 2, 3, 4
    ^^^^^^^
ValueError: too many values to unpack (expected 3, got 4)

PEP 741: Python Configuration C API

Add a PyInitConfig C API to configure the Python initialization without relying on C structures and the ability to make ABI-compatible changes in the future.

Complete the PEP 587 [https://peps.python.org/pep-0587/] PyConfig C API by adding PyInitConfig_AddModule() which can be used to add a built-in extension module; feature previously referred to as the “inittab”.

Add PyConfig_Get() and PyConfig_Set() functions to get and set the current runtime configuration.

PEP 587 “Python Initialization Configuration” unified all the ways to configure the Python initialization. This PEP unifies also the configuration of the Python preinitialization and the Python initialization in a single API. Moreover, this PEP only provides a single choice to embed Python, instead of having two “Python” and “Isolated” choices (PEP 587), to simplify the API further.

The lower level PEP 587 PyConfig API remains available for use cases with an intentionally higher level of coupling to CPython implementation details (such as emulating the full functionality of CPython’s CLI, including its configuration mechanisms).

(Contributed by Victor Stinner in gh-107954 [https://github.com/python/cpython/issues/107954].)

더 보기

PEP 741 [https://peps.python.org/pep-0741/].

Other language changes

The map() built-in now has an optional keyword-only strict flag like zip() to check that all the iterables are of equal length. (Contributed by Wannes Boeykens in gh-119793 [https://github.com/python/cpython/issues/119793].)

Incorrect usage of await and asynchronous comprehensions is now detected even if the code is optimized away by the -O command-line option. For example, python -O -c 'assert await 1' now produces a SyntaxError. (Contributed by Jelle Zijlstra in gh-121637 [https://github.com/python/cpython/issues/121637].)

Writes to __debug__ are now detected even if the code is optimized away by the -O command-line option. For example, python -O -c 'assert (__debug__ := 1)' now produces a SyntaxError. (Contributed by Irit Katriel in gh-122245 [https://github.com/python/cpython/issues/122245].)

Add class methods float.from_number() and complex.from_number() to convert a number to float or complex type correspondingly. They raise an error if the argument is a string. (Contributed by Serhiy Storchaka in gh-84978 [https://github.com/python/cpython/issues/84978].)

Implement mixed-mode arithmetic rules combining real and complex numbers as specified by C standards since C99. (Contributed by Sergey B Kirpichev in gh-69639 [https://github.com/python/cpython/issues/69639].)

All Windows code pages are now supported as “cpXXX” codecs on Windows. (Contributed by Serhiy Storchaka in gh-123803 [https://github.com/python/cpython/issues/123803].)

super objects are now pickleable and copyable. (Contributed by Serhiy Storchaka in gh-125767 [https://github.com/python/cpython/issues/125767].)

The memoryview type now supports subscription, making it a generic type. (Contributed by Brian Schubert in gh-126012 [https://github.com/python/cpython/issues/126012].)

New modules

annotationlib: For introspecting annotations. See PEP 749 [https://peps.python.org/pep-0749/] for more details. (Contributed by Jelle Zijlstra in gh-119180 [https://github.com/python/cpython/issues/119180].)

Improved modules

argparse

The default value of the program name for argparse.ArgumentParser now reflects the way the Python interpreter was instructed to find the __main__ module code. (Contributed by Serhiy Storchaka and Alyssa Coghlan in gh-66436 [https://github.com/python/cpython/issues/66436].)

Introduced the optional suggest_on_error parameter to argparse.ArgumentParser, enabling suggestions for argument choices and subparser names if mistyped by the user. (Contributed by Savannah Ostrowski in gh-124456 [https://github.com/python/cpython/issues/124456].)

ast

Add ast.compare() for comparing two ASTs. (Contributed by Batuhan Taskaya and Jeremy Hylton in gh-60191 [https://github.com/python/cpython/issues/60191].)

Add support for copy.replace() for AST nodes. (Contributed by Bénédikt Tran in gh-121141 [https://github.com/python/cpython/issues/121141].)

Docstrings are now removed from an optimized AST in optimization level 2. (Contributed by Irit Katriel in gh-123958 [https://github.com/python/cpython/issues/123958].)

The repr() output for AST nodes now includes more information. (Contributed by Tomas R in gh-116022 [https://github.com/python/cpython/issues/116022].)

concurrent.futures

Add InterpreterPoolExecutor, which exposes “subinterpreters (multiple Python interpreters in the same process) to Python code. This is separate from the proposed API in PEP 734 [https://peps.python.org/pep-0734/]. (Contributed by Eric Snow in gh-124548 [https://github.com/python/cpython/issues/124548].)

The default ProcessPoolExecutor start method (see 컨텍스트 및 시작 방법) changed from fork to forkserver on platforms other than macOS & Windows. If you require the threading incompatible fork start method you must explicitly request it by supplying a mp_context to concurrent.futures.ProcessPoolExecutor. (Contributed by Gregory P. Smith in gh-84559 [https://github.com/python/cpython/issues/84559].)

ctypes

The layout of bit fields in Structure and Union now matches platform defaults (GCC/Clang or MVSC) more closely. In particular, fields no longer overlap. (Contributed by Matthias Görgens in gh-97702 [https://github.com/python/cpython/issues/97702].)

The Structure._layout_ class attribute can now be set to help match a non-default ABI. (Contributed by Petr Viktorin in gh-97702 [https://github.com/python/cpython/issues/97702].)

The COMError exception is now public. (Contributed by Jun Komoda in gh-126686 [https://github.com/python/cpython/issues/126686].)

datetime

Add datetime.time.strptime() and datetime.date.strptime(). (Contributed by Wannes Boeykens in gh-41431 [https://github.com/python/cpython/issues/41431].)

decimal

Add alternative Decimal constructor Decimal.from_number(). (Contributed by Serhiy Storchaka in gh-121798 [https://github.com/python/cpython/issues/121798].)

dis

Add support for rendering full source location information of instructions, rather than only the line number. This feature is added to the following interfaces via the show_positions keyword argument:

dis.Bytecode

dis.dis()

dis.distb()

dis.disassemble()

This feature is also exposed via dis --show-positions. (Contributed by Bénédikt Tran in gh-123165 [https://github.com/python/cpython/issues/123165].)

fractions

Add support for converting any objects that have the as_integer_ratio() method to a Fraction. (Contributed by Serhiy Storchaka in gh-82017 [https://github.com/python/cpython/issues/82017].)

Add alternative Fraction constructor Fraction.from_number(). (Contributed by Serhiy Storchaka in gh-121797 [https://github.com/python/cpython/issues/121797].)

functools

Add support to functools.partial() and functools.partialmethod() for functools.Placeholder sentinels to reserve a place for positional arguments. (Contributed by Dominykas Grigonis in gh-119127 [https://github.com/python/cpython/issues/119127].)

Allow the initial parameter of functools.reduce() to be passed as a keyword argument. (Contributed by Sayandip Dutta in gh-125916 [https://github.com/python/cpython/issues/125916].)

getopt

Add support for options with optional arguments. (Contributed by Serhiy Storchaka in gh-126374 [https://github.com/python/cpython/issues/126374].)

Add support for returning intermixed options and non-option arguments in order. (Contributed by Serhiy Storchaka in gh-126390 [https://github.com/python/cpython/issues/126390].)

http

Directory lists and error pages generated by the http.server module allow the browser to apply its default dark mode. (Contributed by Yorik Hansen in gh-123430 [https://github.com/python/cpython/issues/123430].)

inspect

inspect.signature() takes a new argument annotation_format to control the annotationlib.Format used for representing annotations. (Contributed by Jelle Zijlstra in gh-101552 [https://github.com/python/cpython/issues/101552].)

inspect.Signature.format() takes a new argument unquote_annotations. If true, string annotations are displayed without surrounding quotes. (Contributed by Jelle Zijlstra in gh-101552 [https://github.com/python/cpython/issues/101552].)

Add function inspect.ispackage() to determine whether an object is a package or not. (Contributed by Zhikang Yan in gh-125634 [https://github.com/python/cpython/issues/125634].)

json

Add notes for JSON serialization errors that allow to identify the source of the error. (Contributed by Serhiy Storchaka in gh-122163 [https://github.com/python/cpython/issues/122163].)

Enable the json module to work as a script using the -m switch: python -m json. See the JSON command-line interface documentation. (Contributed by Trey Hunner in gh-122873 [https://github.com/python/cpython/issues/122873].)

mimetypes

Add MS and RFC 8081 [https://datatracker.ietf.org/doc/html/rfc8081.html] MIME types for fonts:

Embedded OpenType: application/vnd.ms-fontobject

OpenType Layout (OTF) font/otf

TrueType: font/ttf

WOFF 1.0 font/woff

WOFF 2.0 font/woff2

(Contributed by Sahil Prajapati and Hugo van Kemenade in gh-84852 [https://github.com/python/cpython/issues/84852].)

Add RFC 9559 [https://datatracker.ietf.org/doc/html/rfc9559.html] MIME types for Matroska audiovisual data container structures, containing:

audio with no video: audio/matroska (.mka)

video: video/matroska (.mkv)

stereoscopic video: video/matroska-3d (.mk3d)

(Contributed by Hugo van Kemenade in gh-89416 [https://github.com/python/cpython/issues/89416].)

Add MIME types for images with RFCs:

RFC 1494 [https://datatracker.ietf.org/doc/html/rfc1494.html]: CCITT Group 3 (.g3)

RFC 3362 [https://datatracker.ietf.org/doc/html/rfc3362.html]: Real-time Facsimile, T.38 (.t38)

RFC 3745 [https://datatracker.ietf.org/doc/html/rfc3745.html]: JPEG 2000 (.jp2), extension (.jpx) and compound (.jpm)

RFC 3950 [https://datatracker.ietf.org/doc/html/rfc3950.html]: Tag Image File Format Fax eXtended, TIFF-FX (.tfx)

RFC 4047 [https://datatracker.ietf.org/doc/html/rfc4047.html]: Flexible Image Transport System (.fits)

RFC 7903 [https://datatracker.ietf.org/doc/html/rfc7903.html]: Enhanced Metafile (.emf) and Windows Metafile (.wmf)

(Contributed by Hugo van Kemenade in gh-85957 [https://github.com/python/cpython/issues/85957].)

multiprocessing

The default start method (see 컨텍스트 및 시작 방법) changed from fork to forkserver on platforms other than macOS & Windows where it was already spawn. If you require the threading incompatible fork start method you must explicitly request it using a context from multiprocessing.get_context() (preferred) or change the default via multiprocessing.set_start_method(). (Contributed by Gregory P. Smith in gh-84559 [https://github.com/python/cpython/issues/84559].)

multiprocessing’s "forkserver" start method now authenticates its control socket to avoid solely relying on filesystem permissions to restrict what other processes could cause the forkserver to spawn workers and run code. (Contributed by Gregory P. Smith for gh-97514 [https://github.com/python/cpython/issues/97514].)

The multiprocessing proxy objects for list and dict types gain previously overlooked missing methods:

clear() and copy() for proxies of list.

fromkeys(), reversed(d), d | {}, {} | d, d |= {'b': 2} for proxies of dict.

(Contributed by Roy Hyunjin Han for gh-103134 [https://github.com/python/cpython/issues/103134].)

operator

Two new functions operator.is_none() and operator.is_not_none() have been added, such that operator.is_none(obj) is equivalent to obj is None and operator.is_not_none(obj) is equivalent to obj is not None. (Contributed by Raymond Hettinger and Nico Mexis in gh-115808 [https://github.com/python/cpython/issues/115808].)

os

Add the os.reload_environ() function to update os.environ and os.environb with changes to the environment made by os.putenv(), by os.unsetenv(), or made outside Python in the same process. (Contributed by Victor Stinner in gh-120057 [https://github.com/python/cpython/issues/120057].)

pathlib

Add methods to pathlib.Path to recursively copy or move files and directories:

copy() copies a file or directory tree to a destination.

copy_into() copies into a destination directory.

move() moves a file or directory tree to a destination.

move_into() moves into a destination directory.

(Contributed by Barney Gale in gh-73991 [https://github.com/python/cpython/issues/73991].)

Add pathlib.Path.scandir() to scan a directory and return an iterator of os.DirEntry objects. This is exactly equivalent to calling os.scandir() on a path object.

(Contributed by Barney Gale in gh-125413 [https://github.com/python/cpython/issues/125413].)

pdb

Hardcoded breakpoints (breakpoint() and pdb.set_trace()) now reuse the most recent Pdb instance that calls set_trace(), instead of creating a new one each time. As a result, all the instance specific data like display and commands are preserved across hardcoded breakpoints. (Contributed by Tian Gao in gh-121450 [https://github.com/python/cpython/issues/121450].)

Add a new argument mode to pdb.Pdb. Disable the restart command when pdb is in inline mode. (Contributed by Tian Gao in gh-123757 [https://github.com/python/cpython/issues/123757].)

platform

Add platform.invalidate_caches() to invalidate the cached results.

(Contributed by Bénédikt Tran in gh-122549 [https://github.com/python/cpython/issues/122549].)

pickle

Set the default protocol version on the pickle module to 5. For more details, see pickle protocols.

Add notes for pickle serialization errors that allow to identify the source of the error. (Contributed by Serhiy Storchaka in gh-122213 [https://github.com/python/cpython/issues/122213].)

pydoc

Annotations in help output are now usually displayed in a format closer to that in the original source. (Contributed by Jelle Zijlstra in gh-101552 [https://github.com/python/cpython/issues/101552].)

symtable

Expose the following symtable.Symbol methods:

is_comp_cell()

is_comp_iter()

is_free_class()

(Contributed by Bénédikt Tran in gh-120029 [https://github.com/python/cpython/issues/120029].)

sys

The previously undocumented special function sys.getobjects(), which only exists in specialized builds of Python, may now return objects from other interpreters than the one it’s called in.

unicodedata

The Unicode database has been updated to Unicode 16.0.0.

unittest

unittest discovery supports namespace package as start directory again. It was removed in Python 3.11. (Contributed by Jacob Walls in gh-80958 [https://github.com/python/cpython/issues/80958].)

uuid

Add support for UUID version 8 via uuid.uuid8() as specified in RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html]. (Contributed by Bénédikt Tran in gh-89083 [https://github.com/python/cpython/issues/89083].)

Optimizations

asyncio

asyncio now uses double linked list implementation for native tasks which speeds up execution by 10% on standard pyperformance benchmarks and reduces memory usage. (Contributed by Kumar Aditya in gh-107803 [https://github.com/python/cpython/issues/107803].)

io

io which provides the built-in open() makes less system calls when opening regular files as well as reading whole files. Reading a small operating system cached file in full is up to 15% faster. pathlib.Path.read_bytes() has the most optimizations for reading a file’s bytes in full. (Contributed by Cody Maloney and Victor Stinner in gh-120754 [https://github.com/python/cpython/issues/120754] and gh-90102 [https://github.com/python/cpython/issues/90102].)

Deprecated

argparse:

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated. (Contributed by Savannah Ostrowski in gh-125563 [https://github.com/python/cpython/issues/125563].)

Deprecated the argparse.FileType type converter. Anything with resource management should be done downstream after the arguments are parsed. (Contributed by Serhiy Storchaka in gh-58032 [https://github.com/python/cpython/issues/58032].)

asyncio: asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins: Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

os: Soft deprecate os.popen() and os.spawn* functions. They should no longer be used to write new code. The subprocess module is recommended instead. (Contributed by Victor Stinner in gh-120743 [https://github.com/python/cpython/issues/120743].)

symtable: Deprecate symtable.Class.get_methods() due to the lack of interest. (Contributed by Bénédikt Tran in gh-119698 [https://github.com/python/cpython/issues/119698].)

urllib.parse: Accepting objects with false values (like 0 and []) except empty strings, byte-like objects and None in urllib.parse functions parse_qsl() and parse_qs() is now deprecated. (Contributed by Serhiy Storchaka in gh-116897 [https://github.com/python/cpython/issues/116897].)

Pending removal in Python 3.15

The import system:

Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

Setting __package__ on a module while failing to set __spec__.parent is deprecated. In Python 3.15, __package__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

ctypes:

The undocumented ctypes.SetPointerType() function has been deprecated since Python 3.13.

http.server:

The obsolete and rarely used CGIHTTPRequestHandler has been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.

The --cgi flag to the python -m http.server command-line interface has been deprecated since Python 3.13.

locale:

The getdefaultlocale() function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817 [https://github.com/python/cpython/issues/90817]), but has been postponed to Python 3.15. Use getlocale(), setlocale(), and getencoding() instead. (Contributed by Hugo van Kemenade in gh-111187 [https://github.com/python/cpython/issues/111187].)

pathlib:

PurePath.is_reserved() has been deprecated since Python 3.13. Use os.path.isreserved() to detect reserved paths on Windows.

platform:

java_ver() has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.

threading:

RLock() will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.

types:

types.CodeType: Accessing co_lnotab was deprecated in PEP 626 [https://peps.python.org/pep-0626/] since 3.10 and was planned to be removed in 3.12, but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

typing:

The undocumented keyword argument syntax for creating NamedTuple classes (for example, Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.

The typing.no_type_check_decorator() decorator function has been deprecated since Python 3.13. After eight years in the typing module, it has yet to be supported by any major type checker.

wave:

The getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes have been deprecated since Python 3.13.

Pending removal in Python 3.16

The import system:

Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

array:

The 'u' format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the 'w' format code (Py_UCS4) for Unicode characters instead.

asyncio:

asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins:

Bitwise inversion on boolean types, ~True or ~False has been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2 and -1). Use not x instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to int explicitly (~int(x)).

shutil:

The ExecError exception has been deprecated since Python 3.14. It has not been used by any function in shutil since Python 3.4, and is now an alias of RuntimeError.

symtable:

The Class.get_methods method has been deprecated since Python 3.14.

sys:

The _enablelegacywindowsfsencoding() function has been deprecated since Python 3.13. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead.

tarfile:

The undocumented and unused TarFile.tarfile attribute has been deprecated since Python 3.13.

Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

argparse:

Nesting argument groups and nesting mutually exclusive groups are deprecated.

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated.

The argparse.FileType type converter is deprecated.

array’s 'u' format code (gh-57281 [https://github.com/python/cpython/issues/57281])

builtins:

bool(NotImplemented).

Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In a future release it will be changed to a syntax error. (gh-87999 [https://github.com/python/cpython/issues/87999])

Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of int.

Support for __float__() method returning a strict subclass of float: these methods will be required to return an instance of float.

Support for __complex__() method returning a strict subclass of complex: these methods will be required to return an instance of complex.

Delegation of int() to __trunc__() method.

Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

codeobject.co_lnotab: use the codeobject.co_lines() method instead.

datetime:

utcnow(): use datetime.datetime.now(tz=datetime.UTC).

utcfromtimestamp(): use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).

gettext: Plural value must be an integer.

importlib:

load_module() method: use exec_module() instead.

cache_from_source() debug_override parameter is deprecated: use the optimization parameter instead.

importlib.metadata:

EntryPoints tuple interface.

Implicit None on return values.

logging: the warn() method has been deprecated since Python 3.3, use warning() instead.

mailbox: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

os: Calling os.register_at_fork() in multi-threaded process.

pydoc.ErrorDuringImport: A tuple value for exc_info parameter is deprecated, use an exception instance.

re: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

sre_compile, sre_constants and sre_parse modules.

shutil: rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

ssl options and protocols:

ssl.SSLContext without protocol argument is deprecated.

ssl.SSLContext: set_npn_protocols() and selected_npn_protocol() are deprecated: use ALPN instead.

ssl.OP_NO_SSL* options

ssl.OP_NO_TLS* options

ssl.PROTOCOL_SSLv3

ssl.PROTOCOL_TLS

ssl.PROTOCOL_TLSv1

ssl.PROTOCOL_TLSv1_1

ssl.PROTOCOL_TLSv1_2

ssl.TLSVersion.SSLv3

ssl.TLSVersion.TLSv1

ssl.TLSVersion.TLSv1_1

sysconfig.is_python_build() check_home parameter is deprecated and ignored.

threading methods:

threading.Condition.notifyAll(): use notify_all().

threading.Event.isSet(): use is_set().

threading.Thread.isDaemon(), threading.Thread.setDaemon(): use threading.Thread.daemon attribute.

threading.Thread.getName(), threading.Thread.setName(): use threading.Thread.name attribute.

threading.currentThread(): use threading.current_thread().

threading.activeCount(): use threading.active_count().

typing.Text (gh-92332 [https://github.com/python/cpython/issues/92332]).

unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.

urllib.parse deprecated functions: urlparse() instead

splitattr()

splithost()

splitnport()

splitpasswd()

splitport()

splitquery()

splittag()

splittype()

splituser()

splitvalue()

to_bytes()

wsgiref: SimpleHandler.stdout.write() should not do partial writes.

xml.etree.ElementTree: Testing the truth value of an Element is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.

zipimport.zipimporter.load_module() is deprecated: use exec_module() instead.

Removed

argparse

Remove the type, choices, and metavar parameters of argparse.BooleanOptionalAction. They were deprecated since 3.12.

Calling add_argument_group() on an argument group, and calling add_argument_group() or add_mutually_exclusive_group() on a mutually exclusive group now raise exceptions. This nesting was never supported, often failed to work correctly, and was unintentionally exposed through inheritance. This functionality has been deprecated since Python 3.11. (Contributed by Savannah Ostrowski in gh-127186 [https://github.com/python/cpython/issues/127186].)

ast

Remove the following classes. They were all deprecated since Python 3.8, and have emitted deprecation warnings since Python 3.12:

ast.Bytes

ast.Ellipsis

ast.NameConstant

ast.Num

ast.Str

Use ast.Constant instead. As a consequence of these removals, user-defined visit_Num, visit_Str, visit_Bytes, visit_NameConstant and visit_Ellipsis methods on custom ast.NodeVisitor subclasses will no longer be called when the NodeVisitor subclass is visiting an AST. Define a visit_Constant method instead.

Also, remove the following deprecated properties on ast.Constant, which were present for compatibility with the now-removed AST classes:

ast.Constant.n

ast.Constant.s

Use ast.Constant.value instead.

(Contributed by Alex Waygood in gh-119562 [https://github.com/python/cpython/issues/119562].)

asyncio

Remove the following classes and functions. They were all deprecated and emitted deprecation warnings since Python 3.12:

asyncio.get_child_watcher()

asyncio.set_child_watcher()

asyncio.AbstractEventLoopPolicy.get_child_watcher()

asyncio.AbstractEventLoopPolicy.set_child_watcher()

asyncio.AbstractChildWatcher

asyncio.FastChildWatcher

asyncio.MultiLoopChildWatcher

asyncio.PidfdChildWatcher

asyncio.SafeChildWatcher

asyncio.ThreadedChildWatcher

(Contributed by Kumar Aditya in gh-120804 [https://github.com/python/cpython/issues/120804].)

Removed implicit creation of event loop by asyncio.get_event_loop(). It now raises a RuntimeError if there is no current event loop. (Contributed by Kumar Aditya in gh-126353 [https://github.com/python/cpython/issues/126353].)

collections.abc

Remove collections.abc.ByteString. It had previously raised a DeprecationWarning since Python 3.12.

email

Remove the isdst parameter from email.utils.localtime(). (Contributed by Hugo van Kemenade in gh-118798 [https://github.com/python/cpython/issues/118798].)

importlib

Remove deprecated importlib.abc classes:

importlib.abc.ResourceReader

importlib.abc.Traversable

importlib.abc.TraversableResources

Use importlib.resources.abc classes instead:

importlib.resources.abc.Traversable

importlib.resources.abc.TraversableResources

(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963 [https://github.com/python/cpython/issues/93963].)

itertools

Remove itertools support for copy, deepcopy, and pickle operations. These had previously raised a DeprecationWarning since Python 3.12. (Contributed by Raymond Hettinger in gh-101588 [https://github.com/python/cpython/issues/101588].)

pathlib

Remove support for passing additional keyword arguments to pathlib.Path. In previous versions, any such arguments are ignored.

Remove support for passing additional positional arguments to pathlib.PurePath.relative_to() and is_relative_to(). In previous versions, any such arguments are joined onto other.

pkgutil

Remove deprecated pkgutil.get_loader() and pkgutil.find_loader(). These had previously raised a DeprecationWarning since Python 3.12. (Contributed by Bénédikt Tran in gh-97850 [https://github.com/python/cpython/issues/97850].)

pty

Remove deprecated pty.master_open() and pty.slave_open(). They had previously raised a DeprecationWarning since Python 3.12. Use pty.openpty() instead. (Contributed by Nikita Sobolev in gh-118824 [https://github.com/python/cpython/issues/118824].)

sqlite3

Remove version and version_info from sqlite3. (Contributed by Hugo van Kemenade in gh-118924 [https://github.com/python/cpython/issues/118924].)

Disallow using a sequence of parameters with named placeholders. This had previously raised a DeprecationWarning since Python 3.12; it will now raise a sqlite3.ProgrammingError. (Contributed by Erlend E. Aasland in gh-118928 [https://github.com/python/cpython/issues/118928] and gh-101693 [https://github.com/python/cpython/issues/101693].)

typing

Remove typing.ByteString. It had previously raised a DeprecationWarning since Python 3.12.

urllib

Remove deprecated Quoter class from urllib.parse. It had previously raised a DeprecationWarning since Python 3.11. (Contributed by Nikita Sobolev in gh-118827 [https://github.com/python/cpython/issues/118827].)

Remove deprecated URLopener and FancyURLopener classes from urllib.request. They had previously raised a DeprecationWarning since Python 3.3.

myopener.open() can be replaced with urlopen(), and myopener.retrieve() can be replaced with urlretrieve(). Customizations to the opener classes can be replaced by passing customized handlers to build_opener().

(Contributed by Barney Gale in gh-84850 [https://github.com/python/cpython/issues/84850].)

Others

Using NotImplemented in a boolean context will now raise a TypeError. It had previously raised a DeprecationWarning since Python 3.9. (Contributed by Jelle Zijlstra in gh-118767 [https://github.com/python/cpython/issues/118767].)

The int() built-in no longer delegates to __trunc__(). Classes that want to support conversion to integer must implement either __int__() or __index__(). (Contributed by Mark Dickinson in gh-119743 [https://github.com/python/cpython/issues/119743].)

Porting to Python 3.14

This section lists previously described changes and other bugfixes that may require changes to your code.

Changes in the Python API

functools.partial is now a method descriptor. Wrap it in staticmethod() if you want to preserve the old behavior. (Contributed by Serhiy Storchaka and Dominykas Grigonis in gh-121027 [https://github.com/python/cpython/issues/121027].)

The locale.nl_langinfo() function now sets temporarily the LC_CTYPE locale in some cases. This temporary change affects other threads. (Contributed by Serhiy Storchaka in gh-69998 [https://github.com/python/cpython/issues/69998].)

Build changes

PEP 761: Discontinuation of PGP signatures

PGP signatures will not be available for CPython 3.14 and onwards. Users verifying artifacts must use Sigstore verification materials [https://www.python.org/downloads/metadata/sigstore/] for verifying CPython artifacts. This change in release process is specified in PEP 761 [https://peps.python.org/pep-0761/].

C API changes

New features

Add PyLong_GetSign() function to get the sign of int objects. (Contributed by Sergey B Kirpichev in gh-116560 [https://github.com/python/cpython/issues/116560].)

Add a new PyUnicodeWriter API to create a Python str object:

PyUnicodeWriter_Create()

PyUnicodeWriter_DecodeUTF8Stateful()

PyUnicodeWriter_Discard()

PyUnicodeWriter_Finish()

PyUnicodeWriter_Format()

PyUnicodeWriter_WriteChar()

PyUnicodeWriter_WriteRepr()

PyUnicodeWriter_WriteStr()

PyUnicodeWriter_WriteSubstring()

PyUnicodeWriter_WriteUCS4()

PyUnicodeWriter_WriteUTF8()

PyUnicodeWriter_WriteWideChar()

(Contributed by Victor Stinner in gh-119182 [https://github.com/python/cpython/issues/119182].)

Add PyIter_NextItem() to replace PyIter_Next(), which has an ambiguous return value. (Contributed by Irit Katriel and Erlend Aasland in gh-105201 [https://github.com/python/cpython/issues/105201].)

Py_Finalize() now deletes all interned strings. This is backwards incompatible to any C-Extension that holds onto an interned string after a call to Py_Finalize() and is then reused after a call to Py_Initialize(). Any issues arising from this behavior will normally result in crashes during the execution of the subsequent call to Py_Initialize() from accessing uninitialized memory. To fix, use an address sanitizer to identify any use-after-free coming from an interned string and deallocate it during module shutdown. (Contributed by Eddie Elizondo in gh-113601 [https://github.com/python/cpython/issues/113601].)

Add PyLong_IsPositive(), PyLong_IsNegative() and PyLong_IsZero() for checking if PyLongObject is positive, negative, or zero, respectively. (Contributed by James Roy and Sergey B Kirpichev in gh-126061 [https://github.com/python/cpython/issues/126061].)

Add new functions to convert C <stdint.h> numbers from/to Python int:

PyLong_AsInt32()

PyLong_AsInt64()

PyLong_AsUInt32()

PyLong_AsUInt64()

PyLong_FromInt32()

PyLong_FromInt64()

PyLong_FromUInt32()

PyLong_FromUInt64()

(Contributed by Victor Stinner in gh-120389 [https://github.com/python/cpython/issues/120389].)

Add PyBytes_Join(sep, iterable) function, similar to sep.join(iterable) in Python. (Contributed by Victor Stinner in gh-121645 [https://github.com/python/cpython/issues/121645].)

Add Py_HashBuffer() to compute and return the hash value of a buffer. (Contributed by Antoine Pitrou and Victor Stinner in gh-122854 [https://github.com/python/cpython/issues/122854].)

Add functions to get and set the current runtime Python configuration (PEP 741 [https://peps.python.org/pep-0741/]):

PyConfig_Get()

PyConfig_GetInt()

PyConfig_Set()

PyConfig_Names()

(Contributed by Victor Stinner in gh-107954 [https://github.com/python/cpython/issues/107954].)

Add functions to configure the Python initialization (PEP 741 [https://peps.python.org/pep-0741/]):

Py_InitializeFromInitConfig()

PyInitConfig_AddModule()

PyInitConfig_Create()

PyInitConfig_Free()

PyInitConfig_FreeStrList()

PyInitConfig_GetError()

PyInitConfig_GetExitCode()

PyInitConfig_GetInt()

PyInitConfig_GetStr()

PyInitConfig_GetStrList()

PyInitConfig_HasOption()

PyInitConfig_SetInt()

PyInitConfig_SetStr()

PyInitConfig_SetStrList()

(Contributed by Victor Stinner in gh-107954 [https://github.com/python/cpython/issues/107954].)

Add PyType_GetBaseByToken() and Py_tp_token slot for easier superclass identification, which attempts to resolve the type checking issue [https://peps.python.org/pep-0630/#type-checking] mentioned in PEP 630 [https://peps.python.org/pep-0630/] (gh-124153 [https://github.com/python/cpython/issues/124153]).

Add PyUnicode_Equal() function to the limited C API: test if two strings are equal. (Contributed by Victor Stinner in gh-124502 [https://github.com/python/cpython/issues/124502].)

Add PyType_Freeze() function to make a type immutable. (Contributed by Victor Stinner in gh-121654 [https://github.com/python/cpython/issues/121654].)

Add PyUnstable_Object_EnableDeferredRefcount() for enabling deferred reference counting, as outlined in PEP 703 [https://peps.python.org/pep-0703/].

Porting to Python 3.14

In the limited C API 3.14 and newer, Py_TYPE() and Py_REFCNT() are now implemented as an opaque function call to hide implementation details. (Contributed by Victor Stinner in gh-120600 [https://github.com/python/cpython/issues/120600] and gh-124127 [https://github.com/python/cpython/issues/124127].)

Deprecated

The Py_HUGE_VAL macro is soft deprecated, use Py_INFINITY instead. (Contributed by Sergey B Kirpichev in gh-120026 [https://github.com/python/cpython/issues/120026].)

Macros Py_IS_NAN, Py_IS_INFINITY and Py_IS_FINITE are soft deprecated, use instead isnan, isinf and isfinite available from math.h since C99. (Contributed by Sergey B Kirpichev in gh-119613 [https://github.com/python/cpython/issues/119613].)

Pending removal in Python 3.15

The bundled copy of libmpdecimal.

The PyImport_ImportModuleNoBlock(): Use PyImport_ImportModule() instead.

PyWeakref_GetObject() and PyWeakref_GET_OBJECT(): Use PyWeakref_GetRef() instead.

Py_UNICODE type and the Py_UNICODE_WIDE macro: Use wchar_t instead.

Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.base_exec_prefix and sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.base_prefix and sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

Py_TPFLAGS_HAVE_FINALIZE: Unneeded since Python 3.8.

PyErr_Fetch(): Use PyErr_GetRaisedException() instead.

PyErr_NormalizeException(): Use PyErr_GetRaisedException() instead.

PyErr_Restore(): Use PyErr_SetRaisedException() instead.

PyModule_GetFilename(): Use PyModule_GetFilenameObject() instead.

PyOS_AfterFork(): Use PyOS_AfterFork_Child() instead.

PySlice_GetIndicesEx(): Use PySlice_Unpack() and PySlice_AdjustIndices() instead.

PyUnicode_AsDecodedObject(): Use PyCodec_Decode() instead.

PyUnicode_AsDecodedUnicode(): Use PyCodec_Decode() instead.

PyUnicode_AsEncodedObject(): Use PyCodec_Encode() instead.

PyUnicode_AsEncodedUnicode(): Use PyCodec_Encode() instead.

PyUnicode_READY(): Unneeded since Python 3.12

PyErr_Display(): Use PyErr_DisplayException() instead.

_PyErr_ChainExceptions(): Use _PyErr_ChainExceptions1() instead.

PyBytesObject.ob_shash member: call PyObject_Hash() instead.

PyDictObject.ma_version_tag member.

Thread Local Storage (TLS) API:

PyThread_create_key(): Use PyThread_tss_alloc() instead.

PyThread_delete_key(): Use PyThread_tss_free() instead.

PyThread_set_key_value(): Use PyThread_tss_set() instead.

PyThread_get_key_value(): Use PyThread_tss_get() instead.

PyThread_delete_key_value(): Use PyThread_tss_delete() instead.

PyThread_ReInitTLS(): Unneeded since Python 3.7.

Removed

Creating immutable types with mutable bases was deprecated since 3.12 and now raises a TypeError.

What’s New In Python 3.13

Editors:

Adam Turner and Thomas Wouters

This article explains the new features in Python 3.13, compared to 3.12. Python 3.13 was released on October 7, 2024. For full details, see the changelog.

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PEP 719 [https://peps.python.org/pep-0719/] – Python 3.13 Release Schedule

Summary – Release Highlights

Python 3.13 is the latest stable release of the Python programming language, with a mix of changes to the language, the implementation and the standard library. The biggest changes include a new interactive interpreter, experimental support for running in a free-threaded mode (PEP 703 [https://peps.python.org/pep-0703/]), and a Just-In-Time compiler (PEP 744 [https://peps.python.org/pep-0744/]).

Error messages continue to improve, with tracebacks now highlighted in color by default. The locals() builtin now has defined semantics for changing the returned mapping, and type parameters now support default values.

The library changes contain removal of deprecated APIs and modules, as well as the usual improvements in user-friendliness and correctness. Several legacy standard library modules have now been removed following their deprecation in Python 3.11 (PEP 594 [https://peps.python.org/pep-0594/]).

This article doesn’t attempt to provide a complete specification of all new features, but instead gives a convenient overview. For full details refer to the documentation, such as the Library Reference and Language Reference. To understand the complete implementation and design rationale for a change, refer to the PEP for a particular new feature; but note that PEPs usually are not kept up-to-date once a feature has been fully implemented. See Porting to Python 3.13 for guidance on upgrading from earlier versions of Python.

Interpreter improvements:

A greatly improved interactive interpreter and improved error messages.

PEP 667 [https://peps.python.org/pep-0667/]: The locals() builtin now has defined semantics when mutating the returned mapping. Python debuggers and similar tools may now more reliably update local variables in optimized scopes even during concurrent code execution.

PEP 703 [https://peps.python.org/pep-0703/]: CPython 3.13 has experimental support for running with the global interpreter lock disabled. See Free-threaded CPython for more details.

PEP 744 [https://peps.python.org/pep-0744/]: A basic JIT compiler was added. It is currently disabled by default (though we may turn it on later). Performance improvements are modest – we expect to improve this over the next few releases.

Color support in the new interactive interpreter, as well as in tracebacks and doctest output. This can be disabled through the PYTHON_COLORS and NO_COLOR [https://no-color.org/] environment variables.

Python data model improvements:

__static_attributes__ stores the names of attributes accessed through self.X in any function in a class body.

__firstlineno__ records the first line number of a class definition.

Significant improvements in the standard library:

Add a new PythonFinalizationError exception, raised when an operation is blocked during finalization.

The argparse module now supports deprecating command-line options, positional arguments, and subcommands.

The new functions base64.z85encode() and base64.z85decode() support encoding and decoding Z85 data [https://rfc.zeromq.org/spec/32/].

The copy module now has a copy.replace() function, with support for many builtin types and any class defining the __replace__() method.

The new dbm.sqlite3 module is now the default dbm backend.

The os module has a suite of new functions for working with Linux’s timer notification file descriptors.

The random module now has a command-line interface.

Security improvements:

ssl.create_default_context() sets ssl.VERIFY_X509_PARTIAL_CHAIN and ssl.VERIFY_X509_STRICT as default flags.

C API improvements:

The Py_mod_gil slot is now used to indicate that an extension module supports running with the GIL disabled.

The PyTime C API has been added, providing access to system clocks.

PyMutex is a new lightweight mutex that occupies a single byte.

There is a new suite of functions for generating PEP 669 [https://peps.python.org/pep-0669/] monitoring events in the C API.

New typing features:

PEP 696 [https://peps.python.org/pep-0696/]: Type parameters (typing.TypeVar, typing.ParamSpec, and typing.TypeVarTuple) now support defaults.

PEP 702 [https://peps.python.org/pep-0702/]: The new warnings.deprecated() decorator adds support for marking deprecations in the type system and at runtime.

PEP 705 [https://peps.python.org/pep-0705/]: typing.ReadOnly can be used to mark an item of a typing.TypedDict as read-only for type checkers.

PEP 742 [https://peps.python.org/pep-0742/]: typing.TypeIs provides more intuitive type narrowing behavior, as an alternative to typing.TypeGuard.

Platform support:

PEP 730 [https://peps.python.org/pep-0730/]: Apple’s iOS is now an officially supported platform, at tier 3 [https://peps.python.org/pep-0011/#tier-3].

PEP 738 [https://peps.python.org/pep-0738/]: Android is now an officially supported platform, at tier 3 [https://peps.python.org/pep-0011/#tier-3].

wasm32-wasi is now supported as a tier 2 [https://peps.python.org/pep-0011/#tier-2] platform.

wasm32-emscripten is no longer an officially supported platform.

Important removals:

PEP 594: The remaining 19 “dead batteries” (legacy stdlib modules) have been removed from the standard library: aifc, audioop, cgi, cgitb, chunk, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu and xdrlib.

Remove the 2to3 tool and lib2to3 module (deprecated in Python 3.11).

Remove the tkinter.tix module (deprecated in Python 3.6).

Remove the locale.resetlocale() function.

Remove the typing.io and typing.re namespaces.

Remove chained classmethod descriptors.

Release schedule changes:

PEP 602 [https://peps.python.org/pep-0602/] (“Annual Release Cycle for Python”) has been updated to extend the full support (‘bugfix’) period for new releases to two years. This updated policy means that:

Python 3.9–3.12 have one and a half years of full support, followed by three and a half years of security fixes.

Python 3.13 and later have two years of full support, followed by three years of security fixes.

New Features

A better interactive interpreter

Python now uses a new interactive shell by default, based on code from the PyPy project [https://pypy.org/]. When the user starts the REPL from an interactive terminal, the following new features are now supported:

Multiline editing with history preservation.

Direct support for REPL-specific commands like help, exit, and quit, without the need to call them as functions.

Prompts and tracebacks with color enabled by default.

Interactive help browsing using F1 with a separate command history.

History browsing using F2 that skips output as well as the >>> and … prompts.

“Paste mode” with F3 that makes pasting larger blocks of code easier (press F3 again to return to the regular prompt).

To disable the new interactive shell, set the PYTHON_BASIC_REPL environment variable. For more on interactive mode, see 대화형 모드.

(Contributed by Pablo Galindo Salgado, Łukasz Langa, and Lysandros Nikolaou in gh-111201 [https://github.com/python/cpython/issues/111201] based on code from the PyPy project. Windows support contributed by Dino Viehland and Anthony Shaw.)

Improved error messages

The interpreter now uses color by default when displaying tracebacks in the terminal. This feature can be controlled via the new PYTHON_COLORS environment variable as well as the canonical NO_COLOR [https://no-color.org/] and FORCE_COLOR [https://force-color.org/] environment variables. (Contributed by Pablo Galindo Salgado in gh-112730 [https://github.com/python/cpython/issues/112730].)

A common mistake is to write a script with the same name as a standard library module. When this results in errors, we now display a more helpful error message:

$ python random.py
Traceback (most recent call last):
  File "/home/me/random.py", line 1, in <module>
    import random
  File "/home/me/random.py", line 3, in <module>
    print(random.randint(5))
          ^^^^^^^^^^^^^^
AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/me/random.py' since it has the same name as the standard library module named 'random' and prevents importing that standard library module)

Similarly, if a script has the same name as a third-party module that it attempts to import and this results in errors, we also display a more helpful error message:

$ python numpy.py
Traceback (most recent call last):
  File "/home/me/numpy.py", line 1, in <module>
    import numpy as np
  File "/home/me/numpy.py", line 3, in <module>
    np.array([1, 2, 3])
    ^^^^^^^^
AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/me/numpy.py' if it has the same name as a library you intended to import)

(Contributed by Shantanu Jain in gh-95754 [https://github.com/python/cpython/issues/95754].)

The error message now tries to suggest the correct keyword argument when an incorrect keyword argument is passed to a function.

>>> "Better error messages!".split(max_split=1)
Traceback (most recent call last):
  File "<python-input-0>", line 1, in <module>
    "Better error messages!".split(max_split=1)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
TypeError: split() got an unexpected keyword argument 'max_split'. Did you mean 'maxsplit'?

(Contributed by Pablo Galindo Salgado and Shantanu Jain in gh-107944 [https://github.com/python/cpython/issues/107944].)

Free-threaded CPython

CPython now has experimental support for running in a free-threaded mode, with the global interpreter lock (GIL) disabled. This is an experimental feature and therefore is not enabled by default. The free-threaded mode requires a different executable, usually called python3.13t or python3.13t.exe. Pre-built binaries marked as free-threaded can be installed as part of the official Windows and macOS installers, or CPython can be built from source with the --disable-gil option.

Free-threaded execution allows for full utilization of the available processing power by running threads in parallel on available CPU cores. While not all software will benefit from this automatically, programs designed with threading in mind will run faster on multi-core hardware. The free-threaded mode is experimental and work is ongoing to improve it: expect some bugs and a substantial single-threaded performance hit. Free-threaded builds of CPython support optionally running with the GIL enabled at runtime using the environment variable PYTHON_GIL or the command-line option -X gil=1.

To check if the current interpreter supports free-threading, python -VV and sys.version contain “experimental free-threading build”. The new sys._is_gil_enabled() function can be used to check whether the GIL is actually disabled in the running process.

C-API extension modules need to be built specifically for the free-threaded build. Extensions that support running with the GIL disabled should use the Py_mod_gil slot. Extensions using single-phase init should use PyUnstable_Module_SetGIL() to indicate whether they support running with the GIL disabled. Importing C extensions that don’t use these mechanisms will cause the GIL to be enabled, unless the GIL was explicitly disabled with the PYTHON_GIL environment variable or the -X gil=0 option. pip 24.1 or newer is required to install packages with C extensions in the free-threaded build.

This work was made possible thanks to many individuals and organizations, including the large community of contributors to Python and third-party projects to test and enable free-threading support. Notable contributors include: Sam Gross, Ken Jin, Donghee Na, Itamar Oren, Matt Page, Brett Simmers, Dino Viehland, Carl Meyer, Nathan Goldbaum, Ralf Gommers, Lysandros Nikolaou, and many others. Many of these contributors are employed by Meta, which has provided significant engineering resources to support this project.

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PEP 703 [https://peps.python.org/pep-0703/] “Making the Global Interpreter Lock Optional in CPython” contains rationale and information surrounding this work.

Porting Extension Modules to Support Free-Threading [https://py-free-threading.github.io/porting/]: A community-maintained porting guide for extension authors.

An experimental just-in-time (JIT) compiler

When CPython is configured and built using the --enable-experimental-jit option, a just-in-time (JIT) compiler is added which may speed up some Python programs. On Windows, use PCbuild/build.bat --experimental-jit to enable the JIT or --experimental-jit-interpreter to enable the Tier 2 interpreter. Build requirements and further supporting information are contained at [https://github.com/python/cpython/blob/main/Tools/jit/README.md] Tools/jit/README.md.

The --enable-experimental-jit option takes these (optional) values, defaulting to yes if --enable-experimental-jit is present without the optional value.

no: Disable the entire Tier 2 and JIT pipeline.

yes: Enable the JIT. To disable the JIT at runtime, pass the environment variable PYTHON_JIT=0.

yes-off: Build the JIT but disable it by default. To enable the JIT at runtime, pass the environment variable PYTHON_JIT=1.

interpreter: Enable the Tier 2 interpreter but disable the JIT. The interpreter can be disabled by running with PYTHON_JIT=0.

The internal architecture is roughly as follows:

We start with specialized Tier 1 bytecode. See What’s new in 3.11 for details.

When the Tier 1 bytecode gets hot enough, it gets translated to a new purely internal intermediate representation (IR), called the Tier 2 IR, and sometimes referred to as micro-ops (“uops”).

The Tier 2 IR uses the same stack-based virtual machine as Tier 1, but the instruction format is better suited to translation to machine code.

We have several optimization passes for Tier 2 IR, which are applied before it is interpreted or translated to machine code.

There is a Tier 2 interpreter, but it is mostly intended for debugging the earlier stages of the optimization pipeline. The Tier 2 interpreter can be enabled by configuring Python with --enable-experimental-jit=interpreter.

When the JIT is enabled, the optimized Tier 2 IR is translated to machine code, which is then executed.

The machine code translation process uses a technique called copy-and-patch. It has no runtime dependencies, but there is a new build-time dependency on LLVM.

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PEP 744 [https://peps.python.org/pep-0744/]

(JIT by Brandt Bucher, inspired by a paper by Haoran Xu and Fredrik Kjolstad. Tier 2 IR by Mark Shannon and Guido van Rossum. Tier 2 optimizer by Ken Jin.)

Defined mutation semantics for locals()

Historically, the expected result of mutating the return value of locals() has been left to individual Python implementations to define. Starting from Python 3.13, PEP 667 [https://peps.python.org/pep-0667/] standardises the historical behavior of CPython for most code execution scopes, but changes optimized scopes (functions, generators, coroutines, comprehensions, and generator expressions) to explicitly return independent snapshots of the currently assigned local variables, including locally referenced nonlocal variables captured in closures.

This change to the semantics of locals() in optimized scopes also affects the default behavior of code execution functions that implicitly target locals() if no explicit namespace is provided (such as exec() and eval()). In previous versions, whether or not changes could be accessed by calling locals() after calling the code execution function was implementation-dependent. In CPython specifically, such code would typically appear to work as desired, but could sometimes fail in optimized scopes based on other code (including debuggers and code execution tracing tools) potentially resetting the shared snapshot in that scope. Now, the code will always run against an independent snapshot of the local variables in optimized scopes, and hence the changes will never be visible in subsequent calls to locals(). To access the changes made in these cases, an explicit namespace reference must now be passed to the relevant function. Alternatively, it may make sense to update affected code to use a higher level code execution API that returns the resulting code execution namespace (e.g. runpy.run_path() when executing Python files from disk).

To ensure debuggers and similar tools can reliably update local variables in scopes affected by this change, FrameType.f_locals now returns a write-through proxy to the frame’s local and locally referenced nonlocal variables in these scopes, rather than returning an inconsistently updated shared dict instance with undefined runtime semantics.

See PEP 667 [https://peps.python.org/pep-0667/] for more details, including related C API changes and deprecations. Porting notes are also provided below for the affected Python APIs and C APIs.

(PEP and implementation contributed by Mark Shannon and Tian Gao in gh-74929 [https://github.com/python/cpython/issues/74929]. Documentation updates provided by Guido van Rossum and Alyssa Coghlan.)

Support for mobile platforms

PEP 730 [https://peps.python.org/pep-0730/]: iOS is now a PEP 11 [https://peps.python.org/pep-0011/] supported platform, with the arm64-apple-ios and arm64-apple-ios-simulator targets at tier 3 (iPhone and iPad devices released after 2013 and the Xcode iOS simulator running on Apple silicon hardware, respectively). x86_64-apple-ios-simulator (the Xcode iOS simulator running on older x86_64 hardware) is not a tier 3 supported platform, but will have best-effort support. (PEP written and implementation contributed by Russell Keith-Magee in gh-114099 [https://github.com/python/cpython/issues/114099].)

PEP 738 [https://peps.python.org/pep-0738/]: Android is now a PEP 11 [https://peps.python.org/pep-0011/] supported platform, with the aarch64-linux-android and x86_64-linux-android targets at tier 3. The 32-bit targets arm-linux-androideabi and i686-linux-android are not tier 3 supported platforms, but will have best-effort support. (PEP written and implementation contributed by Malcolm Smith in gh-116622 [https://github.com/python/cpython/issues/116622].)

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PEP 730 [https://peps.python.org/pep-0730/], PEP 738 [https://peps.python.org/pep-0738/]

Other Language Changes

The compiler now strips common leading whitespace from every line in a docstring. This reduces the size of the bytecode cache (such as .pyc files), with reductions in file size of around 5%, for example in sqlalchemy.orm.session from SQLAlchemy 2.0. This change affects tools that use docstrings, such as doctest.

>>> def spam():
...     """
...         This is a docstring with
...           leading whitespace.
...
...         It even has multiple paragraphs!
...     """
...
>>> spam.__doc__
'\nThis is a docstring with\n  leading whitespace.\n\nIt even has multiple paragraphs!\n'

(Contributed by Inada Naoki in gh-81283 [https://github.com/python/cpython/issues/81283].)

Annotation scopes within class scopes can now contain lambdas and comprehensions. Comprehensions that are located within class scopes are not inlined into their parent scope.

class C[T]:
    type Alias = lambda: T

(Contributed by Jelle Zijlstra in gh-109118 [https://github.com/python/cpython/issues/109118] and gh-118160 [https://github.com/python/cpython/issues/118160].)

Future statements are no longer triggered by relative imports of the __future__ module, meaning that statements of the form from .__future__ import ... are now simply standard relative imports, with no special features activated. (Contributed by Jeremiah Gabriel Pascual in gh-118216 [https://github.com/python/cpython/issues/118216].)

global declarations are now permitted in except blocks when that global is used in the else block. Previously this raised an erroneous SyntaxError. (Contributed by Irit Katriel in gh-111123 [https://github.com/python/cpython/issues/111123].)

Add PYTHON_FROZEN_MODULES, a new environment variable that determines whether frozen modules are ignored by the import machinery, equivalent to the -X frozen_modules command-line option. (Contributed by Yilei Yang in gh-111374 [https://github.com/python/cpython/issues/111374].)

Add support for the perf profiler working without frame pointers [https://en.wikipedia.org/wiki/Call_stack] through the new environment variable PYTHON_PERF_JIT_SUPPORT and command-line option -X perf_jit. (Contributed by Pablo Galindo in gh-118518 [https://github.com/python/cpython/issues/118518].)

The location of a .python_history file can be changed via the new PYTHON_HISTORY environment variable. (Contributed by Levi Sabah, Zackery Spytz and Hugo van Kemenade in gh-73965 [https://github.com/python/cpython/issues/73965].)

Classes have a new __static_attributes__ attribute. This is populated by the compiler with a tuple of the class’s attribute names which are assigned through self.<name> from any function in its body. (Contributed by Irit Katriel in gh-115775 [https://github.com/python/cpython/issues/115775].)

The compiler now creates a __firstlineno__ attribute on classes with the line number of the first line of the class definition. (Contributed by Serhiy Storchaka in gh-118465 [https://github.com/python/cpython/issues/118465].)

The exec() and eval() builtins now accept the globals and locals arguments as keywords. (Contributed by Raphael Gaschignard in gh-105879 [https://github.com/python/cpython/issues/105879])

The compile() builtin now accepts a new flag, ast.PyCF_OPTIMIZED_AST, which is similar to ast.PyCF_ONLY_AST except that the returned AST is optimized according to the value of the optimize argument. (Contributed by Irit Katriel in gh-108113 [https://github.com/python/cpython/issues/108113]).

Add a __name__ attribute on property objects. (Contributed by Eugene Toder in gh-101860 [https://github.com/python/cpython/issues/101860].)

Add PythonFinalizationError, a new exception derived from RuntimeError and used to signal when operations are blocked during finalization. The following callables now raise PythonFinalizationError, instead of RuntimeError:

_thread.start_new_thread()

os.fork()

os.forkpty()

subprocess.Popen

(Contributed by Victor Stinner in gh-114570 [https://github.com/python/cpython/issues/114570].)

Allow the count argument of str.replace() to be a keyword. (Contributed by Hugo van Kemenade in gh-106487 [https://github.com/python/cpython/issues/106487].)

Many functions now emit a warning if a boolean value is passed as a file descriptor argument. This can help catch some errors earlier. (Contributed by Serhiy Storchaka in gh-82626 [https://github.com/python/cpython/issues/82626].)

Added name and mode attributes for compressed and archived file-like objects in the bz2, lzma, tarfile, and zipfile modules. (Contributed by Serhiy Storchaka in gh-115961 [https://github.com/python/cpython/issues/115961].)

New Modules

dbm.sqlite3: An SQLite backend for dbm. (Contributed by Raymond Hettinger and Erlend E. Aasland in gh-100414 [https://github.com/python/cpython/issues/100414].)

Improved Modules

argparse

Add the deprecated parameter to the add_argument() and add_parser() methods, to enable deprecating command-line options, positional arguments, and subcommands. (Contributed by Serhiy Storchaka in gh-83648 [https://github.com/python/cpython/issues/83648].)

array

Add the 'w' type code (Py_UCS4) for Unicode characters. It should be used instead of the deprecated 'u' type code. (Contributed by Inada Naoki in gh-80480 [https://github.com/python/cpython/issues/80480].)

Register array.array as a MutableSequence by implementing the clear() method. (Contributed by Mike Zimin in gh-114894 [https://github.com/python/cpython/issues/114894].)

ast

The constructors of node types in the ast module are now stricter in the arguments they accept, with more intuitive behavior when arguments are omitted.

If an optional field on an AST node is not included as an argument when constructing an instance, the field will now be set to None. Similarly, if a list field is omitted, that field will now be set to an empty list, and if an expr_context field is omitted, it defaults to Load(). (Previously, in all cases, the attribute would be missing on the newly constructed AST node instance.)

In all other cases, where a required argument is omitted, the node constructor will emit a DeprecationWarning. This will raise an exception in Python 3.15. Similarly, passing a keyword argument to the constructor that does not map to a field on the AST node is now deprecated, and will raise an exception in Python 3.15.

These changes do not apply to user-defined subclasses of ast.AST unless the class opts in to the new behavior by defining the AST._field_types mapping.

(Contributed by Jelle Zijlstra in gh-105858 [https://github.com/python/cpython/issues/105858], gh-117486 [https://github.com/python/cpython/issues/117486], and gh-118851 [https://github.com/python/cpython/issues/118851].)

ast.parse() now accepts an optional argument optimize which is passed on to compile(). This makes it possible to obtain an optimized AST. (Contributed by Irit Katriel in gh-108113 [https://github.com/python/cpython/issues/108113].)

asyncio

asyncio.as_completed() now returns an object that is both an asynchronous iterator and a plain iterator of awaitables. The awaitables yielded by asynchronous iteration include original task or future objects that were passed in, making it easier to associate results with the tasks being completed. (Contributed by Justin Arthur in gh-77714 [https://github.com/python/cpython/issues/77714].)

asyncio.loop.create_unix_server() will now automatically remove the Unix socket when the server is closed. (Contributed by Pierre Ossman in gh-111246 [https://github.com/python/cpython/issues/111246].)

DatagramTransport.sendto() will now send zero-length datagrams if called with an empty bytes object. The transport flow control also now accounts for the datagram header when calculating the buffer size. (Contributed by Jamie Phan in gh-115199 [https://github.com/python/cpython/issues/115199].)

Add Queue.shutdown and QueueShutDown to manage queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104228 [https://github.com/python/cpython/issues/104228].)

Add the Server.close_clients() and Server.abort_clients() methods, which more forcefully close an asyncio server. (Contributed by Pierre Ossman in gh-113538 [https://github.com/python/cpython/issues/113538].)

Accept a tuple of separators in StreamReader.readuntil(), stopping when any one of them is encountered. (Contributed by Bruce Merry in gh-81322 [https://github.com/python/cpython/issues/81322].)

Improve the behavior of TaskGroup when an external cancellation collides with an internal cancellation. For example, when two task groups are nested and both experience an exception in a child task simultaneously, it was possible that the outer task group would hang, because its internal cancellation was swallowed by the inner task group.

In the case where a task group is cancelled externally and also must raise an ExceptionGroup, it will now call the parent task’s cancel() method. This ensures that a CancelledError will be raised at the next await, so the cancellation is not lost.

An added benefit of these changes is that task groups now preserve the cancellation count (cancelling()).

In order to handle some corner cases, uncancel() may now reset the undocumented _must_cancel flag when the cancellation count reaches zero.

(Inspired by an issue reported by Arthur Tacca in gh-116720 [https://github.com/python/cpython/issues/116720].)

When TaskGroup.create_task() is called on an inactive TaskGroup, the given coroutine will be closed (which prevents a RuntimeWarning about the given coroutine being never awaited). (Contributed by Arthur Tacca and Jason Zhang in gh-115957 [https://github.com/python/cpython/issues/115957].)

base64

Add z85encode() and z85decode() functions for encoding bytes as Z85 data [https://rfc.zeromq.org/spec/32/] and decoding Z85-encoded data to bytes. (Contributed by Matan Perelman in gh-75299 [https://github.com/python/cpython/issues/75299].)

compileall

The default number of worker threads and processes is now selected using os.process_cpu_count() instead of os.cpu_count(). (Contributed by Victor Stinner in gh-109649 [https://github.com/python/cpython/issues/109649].)

concurrent.futures

The default number of worker threads and processes is now selected using os.process_cpu_count() instead of os.cpu_count(). (Contributed by Victor Stinner in gh-109649 [https://github.com/python/cpython/issues/109649].)

configparser

ConfigParser now has support for unnamed sections, which allows for top-level key-value pairs. This can be enabled with the new allow_unnamed_section parameter. (Contributed by Pedro Sousa Lacerda in gh-66449 [https://github.com/python/cpython/issues/66449].)

copy

The new replace() function and the replace protocol make creating modified copies of objects much simpler. This is especially useful when working with immutable objects. The following types support the replace() function and implement the replace protocol:

collections.namedtuple()

dataclasses.dataclass

datetime.datetime, datetime.date, datetime.time

inspect.Signature, inspect.Parameter

types.SimpleNamespace

code objects

Any user-defined class can also support copy.replace() by defining the __replace__() method. (Contributed by Serhiy Storchaka in gh-108751 [https://github.com/python/cpython/issues/108751].)

ctypes

As a consequence of necessary internal refactoring, initialization of internal metaclasses now happens in __init__ rather than in __new__. This affects projects that subclass these internal metaclasses to provide custom initialization. Generally:

Custom logic that was done in __new__ after calling super().__new__ should be moved to __init__.

To create a class, call the metaclass, not only the metaclass’s __new__ method.

See gh-124520 [https://github.com/python/cpython/issues/124520] for discussion and links to changes in some affected projects.

ctypes.Structure objects have a new _align_ attribute which allows the alignment of the structure being packed to/from memory to be specified explicitly. (Contributed by Matt Sanderson in gh-112433 [https://github.com/python/cpython/issues/112433])

dbm

Add dbm.sqlite3, a new module which implements an SQLite backend, and make it the default dbm backend. (Contributed by Raymond Hettinger and Erlend E. Aasland in gh-100414 [https://github.com/python/cpython/issues/100414].)

Allow removing all items from the database through the new gdbm.clear() and ndbm.clear() methods. (Contributed by Donghee Na in gh-107122 [https://github.com/python/cpython/issues/107122].)

dis

Change the output of dis module functions to show logical labels for jump targets and exception handlers, rather than offsets. The offsets can be added with the new -O command-line option or the show_offsets argument. (Contributed by Irit Katriel in gh-112137 [https://github.com/python/cpython/issues/112137].)

get_instructions() no longer represents cache entries as separate instructions. Instead, it returns them as part of the Instruction, in the new cache_info field. The show_caches argument to get_instructions() is deprecated and no longer has any effect. (Contributed by Irit Katriel in gh-112962 [https://github.com/python/cpython/issues/112962].)

doctest

doctest output is now colored by default. This can be controlled via the new PYTHON_COLORS environment variable as well as the canonical NO_COLOR [https://no-color.org/] and FORCE_COLOR [https://force-color.org/] environment variables. See also Controlling color. (Contributed by Hugo van Kemenade in gh-117225 [https://github.com/python/cpython/issues/117225].)

The DocTestRunner.run() method now counts the number of skipped tests. Add the DocTestRunner.skips and TestResults.skipped attributes. (Contributed by Victor Stinner in gh-108794 [https://github.com/python/cpython/issues/108794].)

email

Headers with embedded newlines are now quoted on output. The generator will now refuse to serialize (write) headers that are improperly folded or delimited, such that they would be parsed as multiple headers or joined with adjacent data. If you need to turn this safety feature off, set verify_generated_headers. (Contributed by Bas Bloemsaat and Petr Viktorin in gh-121650 [https://github.com/python/cpython/issues/121650].)

getaddresses() and parseaddr() now return ('', '') pairs in more situations where invalid email addresses are encountered instead of potentially inaccurate values. The two functions have a new optional strict parameter (default True). To get the old behavior (accepting malformed input), use strict=False. getattr(email.utils, 'supports_strict_parsing', False) can be used to check if the strict parameter is available. (Contributed by Thomas Dwyer and Victor Stinner for gh-102988 [https://github.com/python/cpython/issues/102988] to improve the CVE 2023-27043 [https://www.cve.org/CVERecord?id=CVE-2023-27043] fix.)

fractions

Fraction objects now support the standard format specification mini-language rules for fill, alignment, sign handling, minimum width, and grouping. (Contributed by Mark Dickinson in gh-111320 [https://github.com/python/cpython/issues/111320].)

glob

Add translate(), a function to convert a path specification with shell-style wildcards to a regular expression. (Contributed by Barney Gale in gh-72904 [https://github.com/python/cpython/issues/72904].)

importlib

The following functions in importlib.resources now allow accessing a directory (or tree) of resources, using multiple positional arguments (the encoding and errors arguments in the text-reading functions are now keyword-only):

is_resource()

open_binary()

open_text()

path()

read_binary()

read_text()

These functions are no longer deprecated and are not scheduled for removal. (Contributed by Petr Viktorin in gh-116608 [https://github.com/python/cpython/issues/116608].)

contents() remains deprecated in favor of the fully-featured Traversable API. However, there is now no plan to remove it. (Contributed by Petr Viktorin in gh-116608 [https://github.com/python/cpython/issues/116608].)

io

The IOBase finalizer now logs any errors raised by the close() method with sys.unraisablehook. Previously, errors were ignored silently by default, and only logged in Python Development Mode or when using a Python debug build. (Contributed by Victor Stinner in gh-62948 [https://github.com/python/cpython/issues/62948].)

ipaddress

Add the IPv4Address.ipv6_mapped property, which returns the IPv4-mapped IPv6 address. (Contributed by Charles Machalow in gh-109466 [https://github.com/python/cpython/issues/109466].)

Fix is_global and is_private behavior in IPv4Address, IPv6Address, IPv4Network, and IPv6Network. (Contributed by Jakub Stasiak in gh-113171 [https://github.com/python/cpython/issues/113171].)

itertools

batched() has a new strict parameter, which raises a ValueError if the final batch is shorter than the specified batch size. (Contributed by Raymond Hettinger in gh-113202 [https://github.com/python/cpython/issues/113202].)

marshal

Add the allow_code parameter in module functions. Passing allow_code=False prevents serialization and de-serialization of code objects which are incompatible between Python versions. (Contributed by Serhiy Storchaka in gh-113626 [https://github.com/python/cpython/issues/113626].)

math

The new function fma() performs fused multiply-add operations. This computes x * y + z with only a single round, and so avoids any intermediate loss of precision. It wraps the fma() function provided by C99, and follows the specification of the IEEE 754 “fusedMultiplyAdd” operation for special cases. (Contributed by Mark Dickinson and Victor Stinner in gh-73468 [https://github.com/python/cpython/issues/73468].)

mimetypes

Add the guess_file_type() function to guess a MIME type from a filesystem path. Using paths with guess_type() is now soft deprecated. (Contributed by Serhiy Storchaka in gh-66543 [https://github.com/python/cpython/issues/66543].)

mmap

mmap is now protected from crashing on Windows when the mapped memory is inaccessible due to file system errors or access violations. (Contributed by Jannis Weigend in gh-118209 [https://github.com/python/cpython/issues/118209].)

mmap has a new seekable() method that can be used when a seekable file-like object is required. The seek() method now returns the new absolute position. (Contributed by Donghee Na and Sylvie Liberman in gh-111835 [https://github.com/python/cpython/issues/111835].)

The new UNIX-only trackfd parameter for mmap controls file descriptor duplication; if false, the file descriptor specified by fileno will not be duplicated. (Contributed by Zackery Spytz and Petr Viktorin in gh-78502 [https://github.com/python/cpython/issues/78502].)

multiprocessing

The default number of worker threads and processes is now selected using os.process_cpu_count() instead of os.cpu_count(). (Contributed by Victor Stinner in gh-109649 [https://github.com/python/cpython/issues/109649].)

os

Add process_cpu_count() function to get the number of logical CPU cores usable by the calling thread of the current process. (Contributed by Victor Stinner in gh-109649 [https://github.com/python/cpython/issues/109649].)

cpu_count() and process_cpu_count() can be overridden through the new environment variable PYTHON_CPU_COUNT or the new command-line option -X cpu_count. This option is useful for users who need to limit CPU resources of a container system without having to modify application code or the container itself. (Contributed by Donghee Na in gh-109595 [https://github.com/python/cpython/issues/109595].)

Add a low level interface to Linux’s timer file descriptors [https://manpages.debian.org/timerfd_create(2)] via timerfd_create(), timerfd_settime(), timerfd_settime_ns(), timerfd_gettime(), timerfd_gettime_ns(), TFD_NONBLOCK, TFD_CLOEXEC, TFD_TIMER_ABSTIME, and TFD_TIMER_CANCEL_ON_SET (Contributed by Masaru Tsuchiyama in gh-108277 [https://github.com/python/cpython/issues/108277].)

lchmod() and the follow_symlinks argument of chmod() are both now available on Windows. Note that the default value of follow_symlinks in lchmod() is False on Windows. (Contributed by Serhiy Storchaka in gh-59616 [https://github.com/python/cpython/issues/59616].)

fchmod() and support for file descriptors in chmod() are both now available on Windows. (Contributed by Serhiy Storchaka in gh-113191 [https://github.com/python/cpython/issues/113191].)

On Windows, mkdir() and makedirs() now support passing a mode value of 0o700 to apply access control to the new directory. This implicitly affects tempfile.mkdtemp() and is a mitigation for CVE 2024-4030 [https://www.cve.org/CVERecord?id=CVE-2024-4030]. Other values for mode continue to be ignored. (Contributed by Steve Dower in gh-118486 [https://github.com/python/cpython/issues/118486].)

posix_spawn() now accepts None for the env argument, which makes the newly spawned process use the current process environment. (Contributed by Jakub Kulik in gh-113119 [https://github.com/python/cpython/issues/113119].)

posix_spawn() can now use the POSIX_SPAWN_CLOSEFROM attribute in the file_actions parameter on platforms that support posix_spawn_file_actions_addclosefrom_np(). (Contributed by Jakub Kulik in gh-113117 [https://github.com/python/cpython/issues/113117].)

os.path

Add isreserved() to check if a path is reserved on the current system. This function is only available on Windows. (Contributed by Barney Gale in gh-88569 [https://github.com/python/cpython/issues/88569].)

On Windows, isabs() no longer considers paths starting with exactly one slash (\ or /) to be absolute. (Contributed by Barney Gale and Jon Foster in gh-44626 [https://github.com/python/cpython/issues/44626].)

realpath() now resolves MS-DOS style file names even if the file is not accessible. (Contributed by Moonsik Park in gh-82367 [https://github.com/python/cpython/issues/82367].)

pathlib

Add UnsupportedOperation, which is raised instead of NotImplementedError when a path operation isn’t supported. (Contributed by Barney Gale in gh-89812 [https://github.com/python/cpython/issues/89812].)

Add a new constructor for creating Path objects from ‘file’ URIs (file:///), Path.from_uri(). (Contributed by Barney Gale in gh-107465 [https://github.com/python/cpython/issues/107465].)

Add PurePath.full_match() for matching paths with shell-style wildcards, including the recursive wildcard “**”. (Contributed by Barney Gale in gh-73435 [https://github.com/python/cpython/issues/73435].)

Add the PurePath.parser class attribute to store the implementation of os.path used for low-level path parsing and joining. This will be either posixpath or ntpath.

Add recurse_symlinks keyword-only argument to Path.glob() and rglob(). (Contributed by Barney Gale in gh-77609 [https://github.com/python/cpython/issues/77609].)

Path.glob() and rglob() now return files and directories when given a pattern that ends with “**”. Previously, only directories were returned. (Contributed by Barney Gale in gh-70303 [https://github.com/python/cpython/issues/70303].)

Add the follow_symlinks keyword-only argument to Path.is_file, Path.is_dir, Path.owner(), and Path.group(). (Contributed by Barney Gale in gh-105793 [https://github.com/python/cpython/issues/105793] and Kamil Turek in gh-107962 [https://github.com/python/cpython/issues/107962].)

pdb

breakpoint() and set_trace() now enter the debugger immediately rather than on the next line of code to be executed. This change prevents the debugger from breaking outside of the context when breakpoint() is positioned at the end of the context. (Contributed by Tian Gao in gh-118579 [https://github.com/python/cpython/issues/118579].)

sys.path[0] is no longer replaced by the directory of the script being debugged when sys.flags.safe_path is set. (Contributed by Tian Gao and Christian Walther in gh-111762 [https://github.com/python/cpython/issues/111762].)

zipapp is now supported as a debugging target. (Contributed by Tian Gao in gh-118501 [https://github.com/python/cpython/issues/118501].)

Add ability to move between chained exceptions during post-mortem debugging in pm() using the new exceptions [exc_number] command for Pdb. (Contributed by Matthias Bussonnier in gh-106676 [https://github.com/python/cpython/issues/106676].)

Expressions and statements whose prefix is a pdb command are now correctly identified and executed. (Contributed by Tian Gao in gh-108464 [https://github.com/python/cpython/issues/108464].)

queue

Add Queue.shutdown and ShutDown to manage queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104750 [https://github.com/python/cpython/issues/104750].)

random

Add a command-line interface. (Contributed by Hugo van Kemenade in gh-118131 [https://github.com/python/cpython/issues/118131].)

re

Rename re.error to PatternError for improved clarity. re.error is kept for backward compatibility.

shutil

Support the dir_fd and follow_symlinks keyword arguments in chown(). (Contributed by Berker Peksag and Tahia K in gh-62308 [https://github.com/python/cpython/issues/62308])

site

.pth files are now decoded using UTF-8 first, and then with the locale encoding if UTF-8 decoding fails. (Contributed by Inada Naoki in gh-117802 [https://github.com/python/cpython/issues/117802].)

sqlite3

A ResourceWarning is now emitted if a Connection object is not closed explicitly. (Contributed by Erlend E. Aasland in gh-105539 [https://github.com/python/cpython/issues/105539].)

Add the filter keyword-only parameter to Connection.iterdump() for filtering database objects to dump. (Contributed by Mariusz Felisiak in gh-91602 [https://github.com/python/cpython/issues/91602].)

ssl

The create_default_context() API now includes VERIFY_X509_PARTIAL_CHAIN and VERIFY_X509_STRICT in its default flags.

참고

VERIFY_X509_STRICT may reject pre-RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html] or malformed certificates that the underlying OpenSSL implementation might otherwise accept. Whilst disabling this is not recommended, you can do so using:

import ssl

ctx = ssl.create_default_context()
ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT

(Contributed by William Woodruff in gh-112389 [https://github.com/python/cpython/issues/112389].)

statistics

Add kde() for kernel density estimation. This makes it possible to estimate a continuous probability density function from a fixed number of discrete samples. (Contributed by Raymond Hettinger in gh-115863 [https://github.com/python/cpython/issues/115863].)

Add kde_random() for sampling from an estimated probability density function created by kde(). (Contributed by Raymond Hettinger in gh-115863 [https://github.com/python/cpython/issues/115863].)

subprocess

The subprocess module now uses the posix_spawn() function in more situations.

Notably, when close_fds is True (the default), posix_spawn() will be used when the C library provides posix_spawn_file_actions_addclosefrom_np(), which includes recent versions of Linux, FreeBSD, and Solaris. On Linux, this should perform similarly to the existing Linux vfork() based code.

A private control knob subprocess._USE_POSIX_SPAWN can be set to False if you need to force subprocess to never use posix_spawn(). Please report your reason and platform details in the issue tracker if you set this so that we can improve our API selection logic for everyone. (Contributed by Jakub Kulik in gh-113117 [https://github.com/python/cpython/issues/113117].)

sys

Add the _is_interned() function to test if a string was interned. This function is not guaranteed to exist in all implementations of Python. (Contributed by Serhiy Storchaka in gh-78573 [https://github.com/python/cpython/issues/78573].)

tempfile

On Windows, the default mode 0o700 used by tempfile.mkdtemp() now limits access to the new directory due to changes to os.mkdir(). This is a mitigation for CVE 2024-4030 [https://www.cve.org/CVERecord?id=CVE-2024-4030]. (Contributed by Steve Dower in gh-118486 [https://github.com/python/cpython/issues/118486].)

time

On Windows, monotonic() now uses the QueryPerformanceCounter() clock for a resolution of 1 microsecond, instead of the GetTickCount64() clock which has a resolution of 15.6 milliseconds. (Contributed by Victor Stinner in gh-88494 [https://github.com/python/cpython/issues/88494].)

On Windows, time() now uses the GetSystemTimePreciseAsFileTime() clock for a resolution of 1 microsecond, instead of the GetSystemTimeAsFileTime() clock which has a resolution of 15.6 milliseconds. (Contributed by Victor Stinner in gh-63207 [https://github.com/python/cpython/issues/63207].)

tkinter

Add tkinter widget methods: tk_busy_hold(), tk_busy_configure(), tk_busy_cget(), tk_busy_forget(), tk_busy_current(), and tk_busy_status(). (Contributed by Miguel, klappnase and Serhiy Storchaka in gh-72684 [https://github.com/python/cpython/issues/72684].)

The tkinter widget method wm_attributes() now accepts the attribute name without the minus prefix to get window attributes, for example w.wm_attributes('alpha') and allows specifying attributes and values to set as keyword arguments, for example w.wm_attributes(alpha=0.5). (Contributed by Serhiy Storchaka in gh-43457 [https://github.com/python/cpython/issues/43457].)

wm_attributes() can now return attributes as a dict, by using the new optional keyword-only parameter return_python_dict. (Contributed by Serhiy Storchaka in gh-43457 [https://github.com/python/cpython/issues/43457].)

Text.count() can now return a simple int when the new optional keyword-only parameter return_ints is used. Otherwise, the single count is returned as a 1-tuple or None. (Contributed by Serhiy Storchaka in gh-97928 [https://github.com/python/cpython/issues/97928].)

Support the “vsapi” element type in the element_create() method of tkinter.ttk.Style. (Contributed by Serhiy Storchaka in gh-68166 [https://github.com/python/cpython/issues/68166].)

Add the after_info() method for Tkinter widgets. (Contributed by Cheryl Sabella in gh-77020 [https://github.com/python/cpython/issues/77020].)

Add a new copy_replace() method to PhotoImage to copy a region from one image to another, possibly with pixel zooming, subsampling, or both. (Contributed by Serhiy Storchaka in gh-118225 [https://github.com/python/cpython/issues/118225].)

Add from_coords parameter to the PhotoImage methods copy(), zoom() and subsample(). Add zoom and subsample parameters to the PhotoImage method copy(). (Contributed by Serhiy Storchaka in gh-118225 [https://github.com/python/cpython/issues/118225].)

Add the PhotoImage methods read() to read an image from a file and data() to get the image data. Add background and grayscale parameters to the write() method. (Contributed by Serhiy Storchaka in gh-118271 [https://github.com/python/cpython/issues/118271].)

traceback

Add the exc_type_str attribute to TracebackException, which holds a string display of the exc_type. Deprecate the exc_type attribute, which holds the type object itself. Add parameter save_exc_type (default True) to indicate whether exc_type should be saved. (Contributed by Irit Katriel in gh-112332 [https://github.com/python/cpython/issues/112332].)

Add a new show_group keyword-only parameter to TracebackException.format_exception_only() to (recursively) format the nested exceptions of a BaseExceptionGroup instance. (Contributed by Irit Katriel in gh-105292 [https://github.com/python/cpython/issues/105292].)

types

SimpleNamespace can now take a single positional argument to initialise the namespace’s arguments. This argument must either be a mapping or an iterable of key-value pairs. (Contributed by Serhiy Storchaka in gh-108191 [https://github.com/python/cpython/issues/108191].)

typing

PEP 705 [https://peps.python.org/pep-0705/]: Add ReadOnly, a special typing construct to mark a TypedDict item as read-only for type checkers.

PEP 742 [https://peps.python.org/pep-0742/]: Add TypeIs, a typing construct that can be used to instruct a type checker how to narrow a type.

Add NoDefault, a sentinel object used to represent the defaults of some parameters in the typing module. (Contributed by Jelle Zijlstra in gh-116126 [https://github.com/python/cpython/issues/116126].)

Add get_protocol_members() to return the set of members defining a typing.Protocol. (Contributed by Jelle Zijlstra in gh-104873 [https://github.com/python/cpython/issues/104873].)

Add is_protocol() to check whether a class is a Protocol. (Contributed by Jelle Zijlstra in gh-104873 [https://github.com/python/cpython/issues/104873].)

ClassVar can now be nested in Final, and vice versa. (Contributed by Mehdi Drissi in gh-89547 [https://github.com/python/cpython/issues/89547].)

unicodedata

Update the Unicode database to version 15.1.0 [https://www.unicode.org/versions/Unicode15.1.0/]. (Contributed by James Gerity in gh-109559 [https://github.com/python/cpython/issues/109559].)

venv

Add support for creating source control management (SCM) ignore files in a virtual environment’s directory. By default, Git is supported. This is implemented as opt-in via the API, which can be extended to support other SCMs (EnvBuilder and create()), and opt-out via the CLI, using --without-scm-ignore-files. (Contributed by Brett Cannon in gh-108125 [https://github.com/python/cpython/issues/108125].)

warnings

PEP 702 [https://peps.python.org/pep-0702/]: The new warnings.deprecated() decorator provides a way to communicate deprecations to a static type checker and to warn on usage of deprecated classes and functions. A DeprecationWarning may also be emitted when a decorated function or class is used at runtime. (Contributed by Jelle Zijlstra in gh-104003 [https://github.com/python/cpython/issues/104003].)

xml

Allow controlling Expat >=2.6.0 reparse deferral (CVE 2023-52425 [https://www.cve.org/CVERecord?id=CVE-2023-52425]) by adding five new methods:

xml.etree.ElementTree.XMLParser.flush()

xml.etree.ElementTree.XMLPullParser.flush()

xml.parsers.expat.xmlparser.GetReparseDeferralEnabled()

xml.parsers.expat.xmlparser.SetReparseDeferralEnabled()

xml.sax.expatreader.ExpatParser.flush()

(Contributed by Sebastian Pipping in gh-115623 [https://github.com/python/cpython/issues/115623].)

Add the close() method for the iterator returned by iterparse() for explicit cleanup. (Contributed by Serhiy Storchaka in gh-69893 [https://github.com/python/cpython/issues/69893].)

zipimport

Add support for ZIP64 [https://en.wikipedia.org/wiki/Zip_(file_format)#ZIP64] format files. Everybody loves huge data, right? (Contributed by Tim Hatch in gh-94146 [https://github.com/python/cpython/issues/94146].)

Optimizations

Several standard library modules have had their import times significantly improved. For example, the import time of the typing module has been reduced by around a third by removing dependencies on re and contextlib. Other modules to enjoy import-time speedups include email.utils, enum, functools, importlib.metadata, and threading. (Contributed by Alex Waygood, Shantanu Jain, Adam Turner, Daniel Hollas, and others in gh-109653 [https://github.com/python/cpython/issues/109653].)

textwrap.indent() is now around 30% faster than before for large input. (Contributed by Inada Naoki in gh-107369 [https://github.com/python/cpython/issues/107369].)

The subprocess module now uses the posix_spawn() function in more situations, including when close_fds is True (the default) on many modern platforms. This should provide a notable performance increase when launching processes on FreeBSD and Solaris. See the subprocess section above for details. (Contributed by Jakub Kulik in gh-113117 [https://github.com/python/cpython/issues/113117].)

Removed Modules And APIs

PEP 594: Remove “dead batteries” from the standard library

PEP 594 [https://peps.python.org/pep-0594/] proposed removing 19 modules from the standard library, colloquially referred to as ‘dead batteries’ due to their historic, obsolete, or insecure status. All of the following modules were deprecated in Python 3.11, and are now removed:

aifc

audioop

chunk

cgi and cgitb

cgi.FieldStorage can typically be replaced with urllib.parse.parse_qsl() for GET and HEAD requests, and the email.message module or the multipart [https://pypi.org/project/multipart/] library for POST and PUT requests.

cgi.parse() can be replaced by calling urllib.parse.parse_qs() directly on the desired query string, unless the input is multipart/form-data, which should be replaced as described below for cgi.parse_multipart().

cgi.parse_header() can be replaced with the functionality in the email package, which implements the same MIME RFCs. For example, with email.message.EmailMessage:

from email.message import EmailMessage

msg = EmailMessage()
msg['content-type'] = 'application/json; charset="utf8"'
main, params = msg.get_content_type(), msg['content-type'].params

cgi.parse_multipart() can be replaced with the functionality in the email package, which implements the same MIME RFCs, or with the multipart [https://pypi.org/project/multipart/] library. For example, the email.message.EmailMessage and email.message.Message classes.

crypt and the private _crypt extension. The hashlib module may be an appropriate replacement when simply hashing a value is required. Otherwise, various third-party libraries on PyPI are available:

bcrypt [https://pypi.org/project/bcrypt/]: Modern password hashing for your software and your servers.

passlib [https://pypi.org/project/passlib/]: Comprehensive password hashing framework supporting over 30 schemes.

argon2-cffi [https://pypi.org/project/argon2-cffi/]: The secure Argon2 password hashing algorithm.

legacycrypt [https://pypi.org/project/legacycrypt/]: ctypes wrapper to the POSIX crypt library call and associated functionality.

crypt_r [https://pypi.org/project/crypt_r/]: Fork of the crypt module, wrapper to the crypt_r(3) [https://manpages.debian.org/crypt_r(3)] library call and associated functionality.

imghdr: The filetype [https://pypi.org/project/filetype/], puremagic [https://pypi.org/project/puremagic/], or python-magic [https://pypi.org/project/python-magic/] libraries should be used as replacements. For example, the puremagic.what() function can be used to replace the imghdr.what() function for all file formats that were supported by imghdr.

mailcap: Use the mimetypes module instead.

msilib

nis

nntplib: Use the pynntp [https://pypi.org/project/pynntp/] library from PyPI instead.

ossaudiodev: For audio playback, use the pygame [https://pypi.org/project/pygame/] library from PyPI instead.

pipes: Use the subprocess module instead. Use shlex.quote() to replace the undocumented pipes.quote function.

sndhdr: The filetype [https://pypi.org/project/filetype/], puremagic [https://pypi.org/project/puremagic/], or python-magic [https://pypi.org/project/python-magic/] libraries should be used as replacements.

spwd: Use the python-pam [https://pypi.org/project/python-pam/] library from PyPI instead.

sunau

telnetlib, Use the telnetlib3 [https://pypi.org/project/telnetlib3/] or Exscript [https://pypi.org/project/Exscript/] libraries from PyPI instead.

uu: Use the base64 module instead, as a modern alternative.

xdrlib

(Contributed by Victor Stinner and Zachary Ware in gh-104773 [https://github.com/python/cpython/issues/104773] and gh-104780 [https://github.com/python/cpython/issues/104780].)

2to3

Remove the 2to3 program and the lib2to3 module, previously deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104780 [https://github.com/python/cpython/issues/104780].)

builtins

Remove support for chained classmethod descriptors (introduced in gh-63272 [https://github.com/python/cpython/issues/63272]). These can no longer be used to wrap other descriptors, such as property. The core design of this feature was flawed and led to several problems. To “pass-through” a classmethod, consider using the __wrapped__ attribute that was added in Python 3.10. (Contributed by Raymond Hettinger in gh-89519 [https://github.com/python/cpython/issues/89519].)

Raise a RuntimeError when calling frame.clear() on a suspended frame (as has always been the case for an executing frame). (Contributed by Irit Katriel in gh-79932 [https://github.com/python/cpython/issues/79932].)

configparser

Remove the undocumented LegacyInterpolation class, deprecated in the docstring since Python 3.2, and at runtime since Python 3.11. (Contributed by Hugo van Kemenade in gh-104886 [https://github.com/python/cpython/issues/104886].)

importlib.metadata

Remove deprecated subscript (__getitem__()) access for EntryPoint objects. (Contributed by Jason R. Coombs in gh-113175 [https://github.com/python/cpython/issues/113175].)

locale

Remove the locale.resetlocale() function, deprecated in Python 3.11. Use locale.setlocale(locale.LC_ALL, "") instead. (Contributed by Victor Stinner in gh-104783 [https://github.com/python/cpython/issues/104783].)

opcode

Move opcode.ENABLE_SPECIALIZATION to _opcode.ENABLE_SPECIALIZATION. This field was added in 3.12, it was never documented, and is not intended for external use. (Contributed by Irit Katriel in gh-105481 [https://github.com/python/cpython/issues/105481].)

Remove opcode.is_pseudo(), opcode.MIN_PSEUDO_OPCODE, and opcode.MAX_PSEUDO_OPCODE, which were added in Python 3.12, but were neither documented nor exposed through dis, and were not intended to be used externally. (Contributed by Irit Katriel in gh-105481 [https://github.com/python/cpython/issues/105481].)

pathlib

Remove the ability to use Path objects as context managers. This functionality was deprecated and has had no effect since Python 3.9. (Contributed by Barney Gale in gh-83863 [https://github.com/python/cpython/issues/83863].)

re

Remove the undocumented, deprecated, and broken re.template() function and re.TEMPLATE / re.T flag. (Contributed by Serhiy Storchaka and Nikita Sobolev in gh-105687 [https://github.com/python/cpython/issues/105687].)

tkinter.tix

Remove the tkinter.tix module, deprecated in Python 3.6. The third-party Tix library which the module wrapped is unmaintained. (Contributed by Zachary Ware in gh-75552 [https://github.com/python/cpython/issues/75552].)

turtle

Remove the RawTurtle.settiltangle() method, deprecated in the documentation since Python 3.1 and at runtime since Python 3.11. (Contributed by Hugo van Kemenade in gh-104876 [https://github.com/python/cpython/issues/104876].)

typing

Remove the typing.io and typing.re namespaces, deprecated since Python 3.8. The items in those namespaces can be imported directly from the typing module. (Contributed by Sebastian Rittau in gh-92871 [https://github.com/python/cpython/issues/92871].)

Remove the keyword-argument method of creating TypedDict types, deprecated in Python 3.11. (Contributed by Tomas Roun in gh-104786 [https://github.com/python/cpython/issues/104786].)

unittest

Remove the following unittest functions, deprecated in Python 3.11:

unittest.findTestCases()

unittest.makeSuite()

unittest.getTestCaseNames()

Use TestLoader methods instead:

loadTestsFromModule()

loadTestsFromTestCase()

getTestCaseNames()

(Contributed by Hugo van Kemenade in gh-104835 [https://github.com/python/cpython/issues/104835].)

Remove the untested and undocumented TestProgram.usageExit() method, deprecated in Python 3.11. (Contributed by Hugo van Kemenade in gh-104992 [https://github.com/python/cpython/issues/104992].)

urllib

Remove the cafile, capath, and cadefault parameters of the urllib.request.urlopen() function, deprecated in Python 3.6. Use the context parameter instead with an SSLContext instance. The ssl.SSLContext.load_cert_chain() function can be used to load specific certificates, or let ssl.create_default_context() select the operating system’s trusted certificate authority (CA) certificates. (Contributed by Victor Stinner in gh-105382 [https://github.com/python/cpython/issues/105382].)

webbrowser

Remove the untested and undocumented MacOSX class, deprecated in Python 3.11. Use the MacOSXOSAScript class (introduced in Python 3.2) instead. (Contributed by Hugo van Kemenade in gh-104804 [https://github.com/python/cpython/issues/104804].)

Remove the deprecated MacOSXOSAScript._name attribute. Use the MacOSXOSAScript.name attribute instead. (Contributed by Nikita Sobolev in gh-105546 [https://github.com/python/cpython/issues/105546].)

New Deprecations

User-defined functions:

Deprecate assignment to a function’s __code__ attribute, where the new code object’s type does not match the function’s type. The different types are: plain function, generator, async generator, and coroutine. (Contributed by Irit Katriel in gh-81137 [https://github.com/python/cpython/issues/81137].)

array:

Deprecate the 'u' format code (wchar_t) at runtime. This format code has been deprecated in documentation since Python 3.3, and will be removed in Python 3.16. Use the 'w' format code (Py_UCS4) for Unicode characters instead. (Contributed by Hugo van Kemenade in gh-80480 [https://github.com/python/cpython/issues/80480].)

ctypes:

Deprecate the undocumented SetPointerType() function, to be removed in Python 3.15. (Contributed by Victor Stinner in gh-105733 [https://github.com/python/cpython/issues/105733].)

Soft-deprecate the ARRAY() function in favour of type * length multiplication. (Contributed by Victor Stinner in gh-105733 [https://github.com/python/cpython/issues/105733].)

decimal:

Deprecate the non-standard and undocumented Decimal format specifier 'N', which is only supported in the decimal module’s C implementation. (Contributed by Serhiy Storchaka in gh-89902 [https://github.com/python/cpython/issues/89902].)

dis:

Deprecate the HAVE_ARGUMENT separator. Check membership in hasarg instead. (Contributed by Irit Katriel in gh-109319 [https://github.com/python/cpython/issues/109319].)

getopt and optparse:

Both modules are now soft deprecated, with argparse preferred for new projects. This is a new soft-deprecation for the getopt module, whereas the optparse module was already de facto soft deprecated. (Contributed by Victor Stinner in gh-106535 [https://github.com/python/cpython/issues/106535].)

gettext:

Deprecate non-integer numbers as arguments to functions and methods that consider plural forms in the gettext module, even if no translation was found. (Contributed by Serhiy Storchaka in gh-88434 [https://github.com/python/cpython/issues/88434].)

glob:

Deprecate the undocumented glob0() and glob1() functions. Use glob() and pass a path-like object specifying the root directory to the root_dir parameter instead. (Contributed by Barney Gale in gh-117337 [https://github.com/python/cpython/issues/117337].)

http.server:

Deprecate CGIHTTPRequestHandler, to be removed in Python 3.15. Process-based CGI HTTP servers have been out of favor for a very long time. This code was outdated, unmaintained, and rarely used. It has a high potential for both security and functionality bugs. (Contributed by Gregory P. Smith in gh-109096 [https://github.com/python/cpython/issues/109096].)

Deprecate the --cgi flag to the python -m http.server command-line interface, to be removed in Python 3.15. (Contributed by Gregory P. Smith in gh-109096 [https://github.com/python/cpython/issues/109096].)

mimetypes:

Soft-deprecate file path arguments to guess_type(), use guess_file_type() instead. (Contributed by Serhiy Storchaka in gh-66543 [https://github.com/python/cpython/issues/66543].)

re:

Deprecate passing the optional maxsplit, count, or flags arguments as positional arguments to the module-level split(), sub(), and subn() functions. These parameters will become keyword-only in a future version of Python. (Contributed by Serhiy Storchaka in gh-56166 [https://github.com/python/cpython/issues/56166].)

pathlib:

Deprecate PurePath.is_reserved(), to be removed in Python 3.15. Use os.path.isreserved() to detect reserved paths on Windows. (Contributed by Barney Gale in gh-88569 [https://github.com/python/cpython/issues/88569].)

platform:

Deprecate java_ver(), to be removed in Python 3.15. This function is only useful for Jython support, has a confusing API, and is largely untested. (Contributed by Nikita Sobolev in gh-116349 [https://github.com/python/cpython/issues/116349].)

pydoc:

Deprecate the undocumented ispackage() function. (Contributed by Zackery Spytz in gh-64020 [https://github.com/python/cpython/issues/64020].)

sqlite3:

Deprecate passing more than one positional argument to the connect() function and the Connection constructor. The remaining parameters will become keyword-only in Python 3.15. (Contributed by Erlend E. Aasland in gh-107948 [https://github.com/python/cpython/issues/107948].)

Deprecate passing name, number of arguments, and the callable as keyword arguments for Connection.create_function() and Connection.create_aggregate() These parameters will become positional-only in Python 3.15. (Contributed by Erlend E. Aasland in gh-108278 [https://github.com/python/cpython/issues/108278].)

Deprecate passing the callback callable by keyword for the set_authorizer(), set_progress_handler(), and set_trace_callback() Connection methods. The callback callables will become positional-only in Python 3.15. (Contributed by Erlend E. Aasland in gh-108278 [https://github.com/python/cpython/issues/108278].)

sys:

Deprecate the _enablelegacywindowsfsencoding() function, to be removed in Python 3.16. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead. (Contributed by Inada Naoki in gh-73427 [https://github.com/python/cpython/issues/73427].)

tarfile:

Deprecate the undocumented and unused TarFile.tarfile attribute, to be removed in Python 3.16. (Contributed in gh-115256 [https://github.com/python/cpython/issues/115256].)

traceback:

Deprecate the TracebackException.exc_type attribute. Use TracebackException.exc_type_str instead. (Contributed by Irit Katriel in gh-112332 [https://github.com/python/cpython/issues/112332].)

typing:

Deprecate the undocumented keyword argument syntax for creating NamedTuple classes (e.g. Point = NamedTuple("Point", x=int, y=int)), to be removed in Python 3.15. Use the class-based syntax or the functional syntax instead. (Contributed by Alex Waygood in gh-105566 [https://github.com/python/cpython/issues/105566].)

Deprecate omitting the fields parameter when creating a NamedTuple or typing.TypedDict class, and deprecate passing None to the fields parameter of both types. Python 3.15 will require a valid sequence for the fields parameter. To create a NamedTuple class with zero fields, use class NT(NamedTuple): pass or NT = NamedTuple("NT", ()). To create a TypedDict class with zero fields, use class TD(TypedDict): pass or TD = TypedDict("TD", {}). (Contributed by Alex Waygood in gh-105566 [https://github.com/python/cpython/issues/105566] and gh-105570 [https://github.com/python/cpython/issues/105570].)

Deprecate the typing.no_type_check_decorator() decorator function, to be removed in in Python 3.15. After eight years in the typing module, it has yet to be supported by any major type checker. (Contributed by Alex Waygood in gh-106309 [https://github.com/python/cpython/issues/106309].)

Deprecate typing.AnyStr. In Python 3.16, it will be removed from typing.__all__, and a DeprecationWarning will be emitted at runtime when it is imported or accessed. It will be removed entirely in Python 3.18. Use the new type parameter syntax instead. (Contributed by Michael The in gh-107116 [https://github.com/python/cpython/issues/107116].)

wave:

Deprecate the getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes, to be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096 [https://github.com/python/cpython/issues/105096].)

Pending removal in Python 3.14

argparse: The type, choices, and metavar parameters of argparse.BooleanOptionalAction are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in gh-92248 [https://github.com/python/cpython/issues/92248].)

ast: The following features have been deprecated in documentation since Python 3.8, now cause a DeprecationWarning to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

ast.Num

ast.Str

ast.Bytes

ast.NameConstant

ast.Ellipsis

Use ast.Constant instead. (Contributed by Serhiy Storchaka in gh-90953 [https://github.com/python/cpython/issues/90953].)

asyncio:

The child watcher classes asyncio.MultiLoopChildWatcher, asyncio.FastChildWatcher, asyncio.AbstractChildWatcher and asyncio.SafeChildWatcher are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

asyncio.set_child_watcher(), asyncio.get_child_watcher(), asyncio.AbstractEventLoopPolicy.set_child_watcher() and asyncio.AbstractEventLoopPolicy.get_child_watcher() are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

The get_event_loop() method of the default event loop policy now emits a DeprecationWarning if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in gh-100160 [https://github.com/python/cpython/issues/100160].)

collections.abc: Deprecated collections.abc.ByteString. Prefer Sequence or Buffer. For use in typing, prefer a union, like bytes | bytearray, or collections.abc.Buffer. (Contributed by Shantanu Jain in gh-91896 [https://github.com/python/cpython/issues/91896].)

email: Deprecated the isdst parameter in email.utils.localtime(). (Contributed by Alan Williams in gh-72346 [https://github.com/python/cpython/issues/72346].)

importlib.abc deprecated classes:

importlib.abc.ResourceReader

importlib.abc.Traversable

importlib.abc.TraversableResources

Use importlib.resources.abc classes instead:

importlib.resources.abc.Traversable

importlib.resources.abc.TraversableResources

(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963 [https://github.com/python/cpython/issues/93963].)

itertools had undocumented, inefficient, historically buggy, and inconsistent support for copy, deepcopy, and pickle operations. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in gh-101588 [https://github.com/python/cpython/issues/101588].)

multiprocessing: The default start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where 'fork' is currently the default (gh-84559 [https://github.com/python/cpython/issues/84559]). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the get_context() or set_start_method() APIs to explicitly specify when your code requires 'fork'. See 컨텍스트 및 시작 방법.

pathlib: is_relative_to() and relative_to(): passing additional arguments is deprecated.

pkgutil: pkgutil.find_loader() and :func:!pkgutil.get_loader` now raise DeprecationWarning; use importlib.util.find_spec() instead. (Contributed by Nikita Sobolev in gh-97850 [https://github.com/python/cpython/issues/97850].)

pty:

master_open(): use pty.openpty().

slave_open(): use pty.openpty().

sqlite3:

version and version_info.

execute() and executemany() if named placeholders are used and parameters is a sequence instead of a dict.

typing: typing.ByteString, deprecated since Python 3.9, now causes a DeprecationWarning to be emitted when it is used.

urllib: urllib.parse.Quoter is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168 [https://github.com/python/cpython/issues/88168].)

Pending removal in Python 3.15

The import system:

Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

Setting __package__ on a module while failing to set __spec__.parent is deprecated. In Python 3.15, __package__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

ctypes:

The undocumented ctypes.SetPointerType() function has been deprecated since Python 3.13.

http.server:

The obsolete and rarely used CGIHTTPRequestHandler has been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.

The --cgi flag to the python -m http.server command-line interface has been deprecated since Python 3.13.

locale:

The getdefaultlocale() function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817 [https://github.com/python/cpython/issues/90817]), but has been postponed to Python 3.15. Use getlocale(), setlocale(), and getencoding() instead. (Contributed by Hugo van Kemenade in gh-111187 [https://github.com/python/cpython/issues/111187].)

pathlib:

PurePath.is_reserved() has been deprecated since Python 3.13. Use os.path.isreserved() to detect reserved paths on Windows.

platform:

java_ver() has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.

threading:

RLock() will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.

types:

types.CodeType: Accessing co_lnotab was deprecated in PEP 626 [https://peps.python.org/pep-0626/] since 3.10 and was planned to be removed in 3.12, but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

typing:

The undocumented keyword argument syntax for creating NamedTuple classes (for example, Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.

The typing.no_type_check_decorator() decorator function has been deprecated since Python 3.13. After eight years in the typing module, it has yet to be supported by any major type checker.

wave:

The getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes have been deprecated since Python 3.13.

Pending removal in Python 3.16

The import system:

Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

array:

The 'u' format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the 'w' format code (Py_UCS4) for Unicode characters instead.

asyncio:

asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins:

Bitwise inversion on boolean types, ~True or ~False has been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2 and -1). Use not x instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to int explicitly (~int(x)).

shutil:

The ExecError exception has been deprecated since Python 3.14. It has not been used by any function in shutil since Python 3.4, and is now an alias of RuntimeError.

symtable:

The Class.get_methods method has been deprecated since Python 3.14.

sys:

The _enablelegacywindowsfsencoding() function has been deprecated since Python 3.13. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead.

tarfile:

The undocumented and unused TarFile.tarfile attribute has been deprecated since Python 3.13.

Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

argparse:

Nesting argument groups and nesting mutually exclusive groups are deprecated.

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated.

The argparse.FileType type converter is deprecated.

array’s 'u' format code (gh-57281 [https://github.com/python/cpython/issues/57281])

builtins:

bool(NotImplemented).

Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In a future release it will be changed to a syntax error. (gh-87999 [https://github.com/python/cpython/issues/87999])

Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of int.

Support for __float__() method returning a strict subclass of float: these methods will be required to return an instance of float.

Support for __complex__() method returning a strict subclass of complex: these methods will be required to return an instance of complex.

Delegation of int() to __trunc__() method.

Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

codeobject.co_lnotab: use the codeobject.co_lines() method instead.

datetime:

utcnow(): use datetime.datetime.now(tz=datetime.UTC).

utcfromtimestamp(): use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).

gettext: Plural value must be an integer.

importlib:

load_module() method: use exec_module() instead.

cache_from_source() debug_override parameter is deprecated: use the optimization parameter instead.

importlib.metadata:

EntryPoints tuple interface.

Implicit None on return values.

logging: the warn() method has been deprecated since Python 3.3, use warning() instead.

mailbox: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

os: Calling os.register_at_fork() in multi-threaded process.

pydoc.ErrorDuringImport: A tuple value for exc_info parameter is deprecated, use an exception instance.

re: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

sre_compile, sre_constants and sre_parse modules.

shutil: rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

ssl options and protocols:

ssl.SSLContext without protocol argument is deprecated.

ssl.SSLContext: set_npn_protocols() and selected_npn_protocol() are deprecated: use ALPN instead.

ssl.OP_NO_SSL* options

ssl.OP_NO_TLS* options

ssl.PROTOCOL_SSLv3

ssl.PROTOCOL_TLS

ssl.PROTOCOL_TLSv1

ssl.PROTOCOL_TLSv1_1

ssl.PROTOCOL_TLSv1_2

ssl.TLSVersion.SSLv3

ssl.TLSVersion.TLSv1

ssl.TLSVersion.TLSv1_1

sysconfig.is_python_build() check_home parameter is deprecated and ignored.

threading methods:

threading.Condition.notifyAll(): use notify_all().

threading.Event.isSet(): use is_set().

threading.Thread.isDaemon(), threading.Thread.setDaemon(): use threading.Thread.daemon attribute.

threading.Thread.getName(), threading.Thread.setName(): use threading.Thread.name attribute.

threading.currentThread(): use threading.current_thread().

threading.activeCount(): use threading.active_count().

typing.Text (gh-92332 [https://github.com/python/cpython/issues/92332]).

unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.

urllib.parse deprecated functions: urlparse() instead

splitattr()

splithost()

splitnport()

splitpasswd()

splitport()

splitquery()

splittag()

splittype()

splituser()

splitvalue()

to_bytes()

wsgiref: SimpleHandler.stdout.write() should not do partial writes.

xml.etree.ElementTree: Testing the truth value of an Element is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.

zipimport.zipimporter.load_module() is deprecated: use exec_module() instead.

CPython Bytecode Changes

The oparg of YIELD_VALUE is now 1 if the yield is part of a yield-from or await, and 0 otherwise. The oparg of RESUME was changed to add a bit indicating if the except-depth is 1, which is needed to optimize closing of generators. (Contributed by Irit Katriel in gh-111354 [https://github.com/python/cpython/issues/111354].)

C API Changes

New Features

Add the PyMonitoring C API for generating PEP 669 [https://peps.python.org/pep-0669/] monitoring events:

PyMonitoringState

PyMonitoring_FirePyStartEvent()

PyMonitoring_FirePyResumeEvent()

PyMonitoring_FirePyReturnEvent()

PyMonitoring_FirePyYieldEvent()

PyMonitoring_FireCallEvent()

PyMonitoring_FireLineEvent()

PyMonitoring_FireJumpEvent()

PyMonitoring_FireBranchEvent()

PyMonitoring_FireCReturnEvent()

PyMonitoring_FirePyThrowEvent()

PyMonitoring_FireRaiseEvent()

PyMonitoring_FireCRaiseEvent()

PyMonitoring_FireReraiseEvent()

PyMonitoring_FireExceptionHandledEvent()

PyMonitoring_FirePyUnwindEvent()

PyMonitoring_FireStopIterationEvent()

PyMonitoring_EnterScope()

PyMonitoring_ExitScope()

(Contributed by Irit Katriel in gh-111997 [https://github.com/python/cpython/issues/111997]).

Add PyMutex, a lightweight mutex that occupies a single byte, and the new PyMutex_Lock() and PyMutex_Unlock() functions. PyMutex_Lock() will release the GIL (if currently held) if the operation needs to block. (Contributed by Sam Gross in gh-108724 [https://github.com/python/cpython/issues/108724].)

Add the PyTime C API to provide access to system clocks:

PyTime_t.

PyTime_MIN and PyTime_MAX.

PyTime_AsSecondsDouble().

PyTime_Monotonic().

PyTime_MonotonicRaw().

PyTime_PerfCounter().

PyTime_PerfCounterRaw().

PyTime_Time().

PyTime_TimeRaw().

(Contributed by Victor Stinner and Petr Viktorin in gh-110850 [https://github.com/python/cpython/issues/110850].)

Add the PyDict_ContainsString() function with the same behavior as PyDict_Contains(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*. (Contributed by Victor Stinner in gh-108314 [https://github.com/python/cpython/issues/108314].)

Add the PyDict_GetItemRef() and PyDict_GetItemStringRef() functions, which behave similarly to PyDict_GetItemWithError(), but return a strong reference instead of a borrowed reference. Moreover, these functions return -1 on error, removing the need to check PyErr_Occurred(). (Contributed by Victor Stinner in gh-106004 [https://github.com/python/cpython/issues/106004].)

Add the PyDict_SetDefaultRef() function, which behaves similarly to PyDict_SetDefault(), but returns a strong reference instead of a borrowed reference. This function returns -1 on error, 0 on insertion, and 1 if the key was already present in the dictionary. (Contributed by Sam Gross in gh-112066 [https://github.com/python/cpython/issues/112066].)

Add the PyDict_Pop() and PyDict_PopString() functions to remove a key from a dictionary and optionally return the removed value. This is similar to dict.pop(), though there is no default value, and KeyError is not raised for missing keys. (Contributed by Stefan Behnel and Victor Stinner in gh-111262 [https://github.com/python/cpython/issues/111262].)

Add the PyMapping_GetOptionalItem() and PyMapping_GetOptionalItemString() functions as alternatives to PyObject_GetItem() and PyMapping_GetItemString() respectively. The new functions do not raise KeyError if the requested key is missing from the mapping. These variants are more convenient and faster if a missing key should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106307 [https://github.com/python/cpython/issues/106307].)

Add the PyObject_GetOptionalAttr() and PyObject_GetOptionalAttrString() functions as alternatives to PyObject_GetAttr() and PyObject_GetAttrString() respectively. The new functions do not raise AttributeError if the requested attribute is not found on the object. These variants are more convenient and faster if the missing attribute should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106521 [https://github.com/python/cpython/issues/106521].)

Add the PyErr_FormatUnraisable() function as an extension to PyErr_WriteUnraisable() that allows customizing the warning message. (Contributed by Serhiy Storchaka in gh-108082 [https://github.com/python/cpython/issues/108082].)

Add new functions that return a strong reference instead of a borrowed reference for frame locals, globals, and builtins, as part of PEP 667:

PyEval_GetFrameBuiltins() replaces PyEval_GetBuiltins()

PyEval_GetFrameGlobals() replaces PyEval_GetGlobals()

PyEval_GetFrameLocals() replaces PyEval_GetLocals()

(Contributed by Mark Shannon and Tian Gao in gh-74929 [https://github.com/python/cpython/issues/74929].)

Add the Py_GetConstant() and Py_GetConstantBorrowed() functions to get strong or borrowed references to constants. For example, Py_GetConstant(Py_CONSTANT_ZERO) returns a strong reference to the constant zero. (Contributed by Victor Stinner in gh-115754 [https://github.com/python/cpython/issues/115754].)

Add the PyImport_AddModuleRef() function as a replacement for PyImport_AddModule() that returns a strong reference instead of a borrowed reference. (Contributed by Victor Stinner in gh-105922 [https://github.com/python/cpython/issues/105922].)

Add the Py_IsFinalizing() function to check whether the main Python interpreter is shutting down. (Contributed by Victor Stinner in gh-108014 [https://github.com/python/cpython/issues/108014].)

Add the PyList_GetItemRef() function as a replacement for PyList_GetItem() that returns a strong reference instead of a borrowed reference. (Contributed by Sam Gross in gh-114329 [https://github.com/python/cpython/issues/114329].)

Add the PyList_Extend() and PyList_Clear() functions, mirroring the Python list.extend() and list.clear() methods. (Contributed by Victor Stinner in gh-111138 [https://github.com/python/cpython/issues/111138].)

Add the PyLong_AsInt() function. It behaves similarly to PyLong_AsLong(), but stores the result in a C int instead of a C long. (Contributed by Victor Stinner in gh-108014 [https://github.com/python/cpython/issues/108014].)

Add the PyLong_AsNativeBytes(), PyLong_FromNativeBytes(), and PyLong_FromUnsignedNativeBytes() functions to simplify converting between native integer types and Python int objects. (Contributed by Steve Dower in gh-111140 [https://github.com/python/cpython/issues/111140].)

Add PyModule_Add() function, which is similar to PyModule_AddObjectRef() and PyModule_AddObject(), but always steals a reference to the value. (Contributed by Serhiy Storchaka in gh-86493 [https://github.com/python/cpython/issues/86493].)

Add the PyObject_GenericHash() function that implements the default hashing function of a Python object. (Contributed by Serhiy Storchaka in gh-113024 [https://github.com/python/cpython/issues/113024].)

Add the Py_HashPointer() function to hash a raw pointer. (Contributed by Victor Stinner in gh-111545 [https://github.com/python/cpython/issues/111545].)

Add the PyObject_VisitManagedDict() and PyObject_ClearManagedDict() functions. which must be called by the traverse and clear functions of a type using the Py_TPFLAGS_MANAGED_DICT flag. The pythoncapi-compat project [https://github.com/python/pythoncapi-compat/] can be used to use these functions with Python 3.11 and 3.12. (Contributed by Victor Stinner in gh-107073 [https://github.com/python/cpython/issues/107073].)

Add the PyRefTracer_SetTracer() and PyRefTracer_GetTracer() functions, which enable tracking object creation and destruction in the same way that the tracemalloc module does. (Contributed by Pablo Galindo in gh-93502 [https://github.com/python/cpython/issues/93502].)

Add the PySys_AuditTuple() function as an alternative to PySys_Audit() that takes event arguments as a Python tuple object. (Contributed by Victor Stinner in gh-85283 [https://github.com/python/cpython/issues/85283].)

Add the PyThreadState_GetUnchecked() function as an alternative to PyThreadState_Get() that doesn’t kill the process with a fatal error if it is NULL. The caller is responsible for checking if the result is NULL. (Contributed by Victor Stinner in gh-108867 [https://github.com/python/cpython/issues/108867].)

Add the PyType_GetFullyQualifiedName() function to get the type’s fully qualified name. The module name is prepended if type.__module__ is a string and is not equal to either 'builtins' or '__main__'. (Contributed by Victor Stinner in gh-111696 [https://github.com/python/cpython/issues/111696].)

Add the PyType_GetModuleName() function to get the type’s module name. This is equivalent to getting the type.__module__ attribute. (Contributed by Eric Snow and Victor Stinner in gh-111696 [https://github.com/python/cpython/issues/111696].)

Add the PyUnicode_EqualToUTF8AndSize() and PyUnicode_EqualToUTF8() functions to compare a Unicode object with a const char* UTF-8 encoded string and 1 if they are equal or 0 otherwise. These functions do not raise exceptions. (Contributed by Serhiy Storchaka in gh-110289 [https://github.com/python/cpython/issues/110289].)

Add the PyWeakref_GetRef() function as an alternative to PyWeakref_GetObject() that returns a strong reference or NULL if the referent is no longer live. (Contributed by Victor Stinner in gh-105927 [https://github.com/python/cpython/issues/105927].)

Add fixed variants of functions which silently ignore errors:

PyObject_HasAttrWithError() replaces PyObject_HasAttr().

PyObject_HasAttrStringWithError() replaces PyObject_HasAttrString().

PyMapping_HasKeyWithError() replaces PyMapping_HasKey().

PyMapping_HasKeyStringWithError() replaces PyMapping_HasKeyString().

The new functions return -1 for errors and the standard 1 for true and 0 for false.

(Contributed by Serhiy Storchaka in gh-108511 [https://github.com/python/cpython/issues/108511].)

Changed C APIs

The keywords parameter of PyArg_ParseTupleAndKeywords() and PyArg_VaParseTupleAndKeywords() now has type char *const* in C and const char *const* in C++, instead of char**. In C++, this makes these functions compatible with arguments of type const char *const*, const char**, or char *const* without an explicit type cast. In C, the functions only support arguments of type char *const*. This can be overridden with the PY_CXX_CONST macro. (Contributed by Serhiy Storchaka in gh-65210 [https://github.com/python/cpython/issues/65210].)

PyArg_ParseTupleAndKeywords() now supports non-ASCII keyword parameter names. (Contributed by Serhiy Storchaka in gh-110815 [https://github.com/python/cpython/issues/110815].)

The PyCode_GetFirstFree() function is now unstable API and is now named PyUnstable_Code_GetFirstFree(). (Contributed by Bogdan Romanyuk in gh-115781 [https://github.com/python/cpython/issues/115781].)

The PyDict_GetItem(), PyDict_GetItemString(), PyMapping_HasKey(), PyMapping_HasKeyString(), PyObject_HasAttr(), PyObject_HasAttrString(), and PySys_GetObject() functions, each of which clears all errors which occurred when calling them now reports these errors using sys.unraisablehook(). You may replace them with other functions as recommended in the documentation. (Contributed by Serhiy Storchaka in gh-106672 [https://github.com/python/cpython/issues/106672].)

Add support for the %T, %#T, %N and %#N formats to PyUnicode_FromFormat():

%T: Get the fully qualified name of an object type

%#T: As above, but use a colon as the separator

%N: Get the fully qualified name of a type

%#N: As above, but use a colon as the separator

See PEP 737 [https://peps.python.org/pep-0737/] for more information. (Contributed by Victor Stinner in gh-111696 [https://github.com/python/cpython/issues/111696].)

You no longer have to define the PY_SSIZE_T_CLEAN macro before including Python.h when using # formats in format codes. APIs accepting the format codes always use Py_ssize_t for # formats. (Contributed by Inada Naoki in gh-104922 [https://github.com/python/cpython/issues/104922].)

If Python is built in debug mode or with assertions, PyTuple_SET_ITEM() and PyList_SET_ITEM() now check the index argument with an assertion. (Contributed by Victor Stinner in gh-106168 [https://github.com/python/cpython/issues/106168].)

Limited C API Changes

The following functions are now included in the Limited C API:

PyMem_RawMalloc()

PyMem_RawCalloc()

PyMem_RawRealloc()

PyMem_RawFree()

PySys_Audit()

PySys_AuditTuple()

PyType_GetModuleByDef()

(Contributed by Victor Stinner in gh-85283 [https://github.com/python/cpython/issues/85283], gh-85283 [https://github.com/python/cpython/issues/85283], and gh-116936 [https://github.com/python/cpython/issues/116936].)

Python built with --with-trace-refs (tracing references) now supports the Limited API. (Contributed by Victor Stinner in gh-108634 [https://github.com/python/cpython/issues/108634].)

Removed C APIs

Remove several functions, macros, variables, etc with names prefixed by _Py or _PY (which are considered private). If your project is affected by one of these removals and you believe that the removed API should remain available, please open a new issue to request a public C API and add cc: @vstinner to the issue to notify Victor Stinner. (Contributed by Victor Stinner in gh-106320 [https://github.com/python/cpython/issues/106320].)

Remove old buffer protocols deprecated in Python 3.0. Use 버퍼 프로토콜 instead.

PyObject_CheckReadBuffer(): Use PyObject_CheckBuffer() to test whether the object supports the buffer protocol. Note that PyObject_CheckBuffer() doesn’t guarantee that PyObject_GetBuffer() will succeed. To test if the object is actually readable, see the next example of PyObject_GetBuffer().

PyObject_AsCharBuffer(), PyObject_AsReadBuffer(): Use PyObject_GetBuffer() and PyBuffer_Release() instead:

Py_buffer view;
if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) < 0) {
    return NULL;
}
// Use `view.buf` and `view.len` to read from the buffer.
// You may need to cast buf as `(const char*)view.buf`.
PyBuffer_Release(&view);

PyObject_AsWriteBuffer(): Use PyObject_GetBuffer() and PyBuffer_Release() instead:

Py_buffer view;
if (PyObject_GetBuffer(obj, &view, PyBUF_WRITABLE) < 0) {
    return NULL;
}
// Use `view.buf` and `view.len` to write to the buffer.
PyBuffer_Release(&view);

(Contributed by Inada Naoki in gh-85275 [https://github.com/python/cpython/issues/85275].)

Remove various functions deprecated in Python 3.9:

PyEval_CallObject(), PyEval_CallObjectWithKeywords(): Use PyObject_CallNoArgs() or PyObject_Call() instead.

경고

In PyObject_Call(), positional arguments must be a tuple and must not be NULL, and keyword arguments must be a dict or NULL, whereas the removed functions checked argument types and accepted NULL positional and keyword arguments. To replace PyEval_CallObjectWithKeywords(func, NULL, kwargs) with PyObject_Call(), pass an empty tuple as positional arguments using PyTuple_New(0).

PyEval_CallFunction(): Use PyObject_CallFunction() instead.

PyEval_CallMethod(): Use PyObject_CallMethod() instead.

PyCFunction_Call(): Use PyObject_Call() instead.

(Contributed by Victor Stinner in gh-105107 [https://github.com/python/cpython/issues/105107].)

Remove the following old functions to configure the Python initialization, deprecated in Python 3.11:

PySys_AddWarnOptionUnicode(): Use PyConfig.warnoptions instead.

PySys_AddWarnOption(): Use PyConfig.warnoptions instead.

PySys_AddXOption(): Use PyConfig.xoptions instead.

PySys_HasWarnOptions(): Use PyConfig.xoptions instead.

PySys_SetPath(): Set PyConfig.module_search_paths instead.

Py_SetPath(): Set PyConfig.module_search_paths instead.

Py_SetStandardStreamEncoding(): Set PyConfig.stdio_encoding instead, and set also maybe PyConfig.legacy_windows_stdio (on Windows).

_Py_SetProgramFullPath(): Set PyConfig.executable instead.

Use the new PyConfig API of the Python Initialization Configuration instead (PEP 587 [https://peps.python.org/pep-0587/]), added to Python 3.8. (Contributed by Victor Stinner in gh-105145 [https://github.com/python/cpython/issues/105145].)

Remove PyEval_AcquireLock() and PyEval_ReleaseLock() functions, deprecated in Python 3.2. They didn’t update the current thread state. They can be replaced with:

PyEval_SaveThread() and PyEval_RestoreThread();

low-level PyEval_AcquireThread() and PyEval_RestoreThread();

or PyGILState_Ensure() and PyGILState_Release().

(Contributed by Victor Stinner in gh-105182 [https://github.com/python/cpython/issues/105182].)

Remove the PyEval_ThreadsInitialized() function, deprecated in Python 3.9. Since Python 3.7, Py_Initialize() always creates the GIL: calling PyEval_InitThreads() does nothing and PyEval_ThreadsInitialized() always returns non-zero. (Contributed by Victor Stinner in gh-105182 [https://github.com/python/cpython/issues/105182].)

Remove the _PyInterpreterState_Get() alias to PyInterpreterState_Get() which was kept for backward compatibility with Python 3.8. The pythoncapi-compat project [https://github.com/python/pythoncapi-compat/] can be used to get PyInterpreterState_Get() on Python 3.8 and older. (Contributed by Victor Stinner in gh-106320 [https://github.com/python/cpython/issues/106320].)

Remove the private _PyObject_FastCall() function: use PyObject_Vectorcall() which is available since Python 3.8 (PEP 590 [https://peps.python.org/pep-0590/]). (Contributed by Victor Stinner in gh-106023 [https://github.com/python/cpython/issues/106023].)

Remove the cpython/pytime.h header file, which only contained private functions. (Contributed by Victor Stinner in gh-106316 [https://github.com/python/cpython/issues/106316].)

Remove the undocumented PY_TIMEOUT_MAX constant from the limited C API. (Contributed by Victor Stinner in gh-110014 [https://github.com/python/cpython/issues/110014].)

Remove the old trashcan macros Py_TRASHCAN_SAFE_BEGIN and Py_TRASHCAN_SAFE_END. Replace both with the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END. (Contributed by Irit Katriel in gh-105111 [https://github.com/python/cpython/issues/105111].)

Deprecated C APIs

Deprecate old Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

(Contributed by Victor Stinner in gh-105145 [https://github.com/python/cpython/issues/105145].)

Soft deprecate the PyEval_GetBuiltins(), PyEval_GetGlobals(), and PyEval_GetLocals() functions, which return a borrowed reference. (Soft deprecated as part of PEP 667 [https://peps.python.org/pep-0667/].)

Deprecate the PyImport_ImportModuleNoBlock() function, which is just an alias to PyImport_ImportModule() since Python 3.3. (Contributed by Victor Stinner in gh-105396 [https://github.com/python/cpython/issues/105396].)

Soft deprecate the PyModule_AddObject() function. It should be replaced with PyModule_Add() or PyModule_AddObjectRef(). (Contributed by Serhiy Storchaka in gh-86493 [https://github.com/python/cpython/issues/86493].)

Deprecate the old Py_UNICODE and PY_UNICODE_TYPE types and the Py_UNICODE_WIDE define. Use the wchar_t type directly instead. Since Python 3.3, Py_UNICODE and PY_UNICODE_TYPE are just aliases to wchar_t. (Contributed by Victor Stinner in gh-105156 [https://github.com/python/cpython/issues/105156].)

Deprecate the PyWeakref_GetObject() and PyWeakref_GET_OBJECT() functions, which return a borrowed reference. Replace them with the new PyWeakref_GetRef() function, which returns a strong reference. The pythoncapi-compat project [https://github.com/python/pythoncapi-compat/] can be used to get PyWeakref_GetRef() on Python 3.12 and older. (Contributed by Victor Stinner in gh-105927 [https://github.com/python/cpython/issues/105927].)

Pending removal in Python 3.14

The ma_version_tag field in PyDictObject for extension modules (PEP 699 [https://peps.python.org/pep-0699/]; gh-101193 [https://github.com/python/cpython/issues/101193]).

Creating immutable types with mutable bases (gh-95388 [https://github.com/python/cpython/issues/95388]).

Functions to configure Python’s initialization, deprecated in Python 3.11:

PySys_SetArgvEx(): Set PyConfig.argv instead.

PySys_SetArgv(): Set PyConfig.argv instead.

Py_SetProgramName(): Set PyConfig.program_name instead.

Py_SetPythonHome(): Set PyConfig.home instead.

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Global configuration variables:

Py_DebugFlag: Use PyConfig.parser_debug instead.

Py_VerboseFlag: Use PyConfig.verbose instead.

Py_QuietFlag: Use PyConfig.quiet instead.

Py_InteractiveFlag: Use PyConfig.interactive instead.

Py_InspectFlag: Use PyConfig.inspect instead.

Py_OptimizeFlag: Use PyConfig.optimization_level instead.

Py_NoSiteFlag: Use PyConfig.site_import instead.

Py_BytesWarningFlag: Use PyConfig.bytes_warning instead.

Py_FrozenFlag: Use PyConfig.pathconfig_warnings instead.

Py_IgnoreEnvironmentFlag: Use PyConfig.use_environment instead.

Py_DontWriteBytecodeFlag: Use PyConfig.write_bytecode instead.

Py_NoUserSiteDirectory: Use PyConfig.user_site_directory instead.

Py_UnbufferedStdioFlag: Use PyConfig.buffered_stdio instead.

Py_HashRandomizationFlag: Use PyConfig.use_hash_seed and PyConfig.hash_seed instead.

Py_IsolatedFlag: Use PyConfig.isolated instead.

Py_LegacyWindowsFSEncodingFlag: Use PyPreConfig.legacy_windows_fs_encoding instead.

Py_LegacyWindowsStdioFlag: Use PyConfig.legacy_windows_stdio instead.

Py_FileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_HasFileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_FileSystemDefaultEncodeErrors: Use PyConfig.filesystem_errors instead.

Py_UTF8Mode: Use PyPreConfig.utf8_mode instead. (see Py_PreInitialize())

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Pending removal in Python 3.15

The bundled copy of libmpdecimal.

The PyImport_ImportModuleNoBlock(): Use PyImport_ImportModule() instead.

PyWeakref_GetObject() and PyWeakref_GET_OBJECT(): Use PyWeakref_GetRef() instead.

Py_UNICODE type and the Py_UNICODE_WIDE macro: Use wchar_t instead.

Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.base_exec_prefix and sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.base_prefix and sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

Py_TPFLAGS_HAVE_FINALIZE: Unneeded since Python 3.8.

PyErr_Fetch(): Use PyErr_GetRaisedException() instead.

PyErr_NormalizeException(): Use PyErr_GetRaisedException() instead.

PyErr_Restore(): Use PyErr_SetRaisedException() instead.

PyModule_GetFilename(): Use PyModule_GetFilenameObject() instead.

PyOS_AfterFork(): Use PyOS_AfterFork_Child() instead.

PySlice_GetIndicesEx(): Use PySlice_Unpack() and PySlice_AdjustIndices() instead.

PyUnicode_AsDecodedObject(): Use PyCodec_Decode() instead.

PyUnicode_AsDecodedUnicode(): Use PyCodec_Decode() instead.

PyUnicode_AsEncodedObject(): Use PyCodec_Encode() instead.

PyUnicode_AsEncodedUnicode(): Use PyCodec_Encode() instead.

PyUnicode_READY(): Unneeded since Python 3.12

PyErr_Display(): Use PyErr_DisplayException() instead.

_PyErr_ChainExceptions(): Use _PyErr_ChainExceptions1() instead.

PyBytesObject.ob_shash member: call PyObject_Hash() instead.

PyDictObject.ma_version_tag member.

Thread Local Storage (TLS) API:

PyThread_create_key(): Use PyThread_tss_alloc() instead.

PyThread_delete_key(): Use PyThread_tss_free() instead.

PyThread_set_key_value(): Use PyThread_tss_set() instead.

PyThread_get_key_value(): Use PyThread_tss_get() instead.

PyThread_delete_key_value(): Use PyThread_tss_delete() instead.

PyThread_ReInitTLS(): Unneeded since Python 3.7.

Build Changes

arm64-apple-ios and arm64-apple-ios-simulator are both now PEP 11 [https://peps.python.org/pep-0011/] tier 3 platforms. (PEP 730 written and implementation contributed by Russell Keith-Magee in gh-114099 [https://github.com/python/cpython/issues/114099].)

aarch64-linux-android and x86_64-linux-android are both now PEP 11 [https://peps.python.org/pep-0011/] tier 3 platforms. (PEP 738 written and implementation contributed by Malcolm Smith in gh-116622 [https://github.com/python/cpython/issues/116622].)

wasm32-wasi is now a PEP 11 [https://peps.python.org/pep-0011/] tier 2 platform. (Contributed by Brett Cannon in gh-115192 [https://github.com/python/cpython/issues/115192].)

wasm32-emscripten is no longer a PEP 11 [https://peps.python.org/pep-0011/] supported platform. (Contributed by Brett Cannon in gh-115192 [https://github.com/python/cpython/issues/115192].)

Building CPython now requires a compiler with support for the C11 atomic library, GCC built-in atomic functions, or MSVC interlocked intrinsics.

Autoconf 2.71 and aclocal 1.16.5 are now required to regenerate the configure script. (Contributed by Christian Heimes in gh-89886 [https://github.com/python/cpython/issues/89886] and by Victor Stinner in gh-112090 [https://github.com/python/cpython/issues/112090].)

SQLite 3.15.2 or newer is required to build the sqlite3 extension module. (Contributed by Erlend Aasland in gh-105875 [https://github.com/python/cpython/issues/105875].)

CPython now bundles the mimalloc library [https://github.com/microsoft/mimalloc/] by default. It is licensed under the MIT license; see mimalloc license. The bundled mimalloc has custom changes, see gh-113141 [https://github.com/python/cpython/issues/113141] for details. (Contributed by Dino Viehland in gh-109914 [https://github.com/python/cpython/issues/109914].)

The configure option --with-system-libmpdec now defaults to yes. The bundled copy of libmpdecimal will be removed in Python 3.15.

Python built with configure --with-trace-refs (tracing references) is now ABI compatible with the Python release build and debug build. (Contributed by Victor Stinner in gh-108634 [https://github.com/python/cpython/issues/108634].)

On POSIX systems, the pkg-config (.pc) filenames now include the ABI flags. For example, the free-threaded build generates python-3.13t.pc and the debug build generates python-3.13d.pc.

The errno, fcntl, grp, md5, pwd, resource, termios, winsound, _ctypes_test, _multiprocessing.posixshmem, _scproxy, _stat, _statistics, _testconsole, _testimportmultiple and _uuid C extensions are now built with the limited C API. (Contributed by Victor Stinner in gh-85283 [https://github.com/python/cpython/issues/85283].)

Porting to Python 3.13

This section lists previously described changes and other bugfixes that may require changes to your code.

Changes in the Python API

PEP 667 introduces several changes to the semantics of locals() and f_locals:

Calling locals() in an optimized scope now produces an independent snapshot on each call, and hence no longer implicitly updates previously returned references. Obtaining the legacy CPython behavior now requires explicit calls to update the initially returned dictionary with the results of subsequent calls to locals(). Code execution functions that implicitly target locals() (such as exec and eval) must be passed an explicit namespace to access their results in an optimized scope. (Changed as part of PEP 667 [https://peps.python.org/pep-0667/].)

Calling locals() from a comprehension at module or class scope (including via exec or eval) once more behaves as if the comprehension were running as an independent nested function (i.e. the local variables from the containing scope are not included). In Python 3.12, this had changed to include the local variables from the containing scope when implementing PEP 709 [https://peps.python.org/pep-0709/]. (Changed as part of PEP 667 [https://peps.python.org/pep-0667/].)

Accessing FrameType.f_locals in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly with dict or the proxy’s .copy() method. (Changed as part of PEP 667 [https://peps.python.org/pep-0667/].)

functools.partial now emits a FutureWarning when used as a method. The behavior will change in future Python versions. Wrap it in staticmethod() if you want to preserve the old behavior. (Contributed by Serhiy Storchaka in gh-121027 [https://github.com/python/cpython/issues/121027].)

An OSError is now raised by getpass.getuser() for any failure to retrieve a username, instead of ImportError on non-Unix platforms or KeyError on Unix platforms where the password database is empty.

The value of the mode attribute of gzip.GzipFile is now a string ('rb' or 'wb') instead of an integer (1 or 2). The value of the mode attribute of the readable file-like object returned by zipfile.ZipFile.open() is now 'rb' instead of 'r'. (Contributed by Serhiy Storchaka in gh-115961 [https://github.com/python/cpython/issues/115961].)

mailbox.Maildir now ignores files with a leading dot (.). (Contributed by Zackery Spytz in gh-65559 [https://github.com/python/cpython/issues/65559].)

pathlib.Path.glob() and rglob() now return both files and directories if a pattern that ends with “**” is given, rather than directories only. Add a trailing slash to keep the previous behavior and only match directories.

The threading module now expects the _thread module to have an _is_main_interpreter() function. This function takes no arguments and returns True if the current interpreter is the main interpreter.

Any library or application that provides a custom _thread module must provide _is_main_interpreter(), just like the module’s other “private” attributes. (gh-112826 [https://github.com/python/cpython/issues/112826].)

Changes in the C API

Python.h no longer includes the <ieeefp.h> standard header. It was included for the finite() function which is now provided by the <math.h> header. It should now be included explicitly if needed. Remove also the HAVE_IEEEFP_H macro. (Contributed by Victor Stinner in gh-108765 [https://github.com/python/cpython/issues/108765].)

Python.h no longer includes these standard header files: <time.h>, <sys/select.h> and <sys/time.h>. If needed, they should now be included explicitly. For example, <time.h> provides the clock() and gmtime() functions, <sys/select.h> provides the select() function, and <sys/time.h> provides the futimes(), gettimeofday() and setitimer() functions. (Contributed by Victor Stinner in gh-108765 [https://github.com/python/cpython/issues/108765].)

On Windows, Python.h no longer includes the <stddef.h> standard header file. If needed, it should now be included explicitly. For example, it provides offsetof() function, and size_t and ptrdiff_t types. Including <stddef.h> explicitly was already needed by all other platforms, the HAVE_STDDEF_H macro is only defined on Windows. (Contributed by Victor Stinner in gh-108765 [https://github.com/python/cpython/issues/108765].)

If the Py_LIMITED_API macro is defined, Py_BUILD_CORE, Py_BUILD_CORE_BUILTIN and Py_BUILD_CORE_MODULE macros are now undefined by <Python.h>. (Contributed by Victor Stinner in gh-85283 [https://github.com/python/cpython/issues/85283].)

The old trashcan macros Py_TRASHCAN_SAFE_BEGIN and Py_TRASHCAN_SAFE_END were removed. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END.

A tp_dealloc function that has the old macros, such as:

static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_SAFE_BEGIN(p);
    ...
    Py_TRASHCAN_SAFE_END
}

should migrate to the new macros as follows:

static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_BEGIN(p, mytype_dealloc)
    ...
    Py_TRASHCAN_END
}

Note that Py_TRASHCAN_BEGIN has a second argument which should be the deallocation function it is in. The new macros were added in Python 3.8 and the old macros were deprecated in Python 3.11. (Contributed by Irit Katriel in gh-105111 [https://github.com/python/cpython/issues/105111].)

PEP 667 introduces several changes to frame-related functions:

The effects of mutating the dictionary returned from PyEval_GetLocals() in an optimized scope have changed. New dict entries added this way will now only be visible to subsequent PyEval_GetLocals() calls in that frame, as PyFrame_GetLocals(), locals(), and FrameType.f_locals no longer access the same underlying cached dictionary. Changes made to entries for actual variable names and names added via the write-through proxy interfaces will be overwritten on subsequent calls to PyEval_GetLocals() in that frame. The recommended code update depends on how the function was being used, so refer to the deprecation notice on the function for details.

Calling PyFrame_GetLocals() in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly (e.g. with PyDict_Copy()), or by calling the new PyEval_GetFrameLocals() API.

PyFrame_FastToLocals() and PyFrame_FastToLocalsWithError() no longer have any effect. Calling these functions has been redundant since Python 3.11, when PyFrame_GetLocals() was first introduced.

PyFrame_LocalsToFast() no longer has any effect. Calling this function is redundant now that PyFrame_GetLocals() returns a write-through proxy for optimized scopes.

Regression Test Changes

Python built with configure --with-pydebug now supports a -X presite=package.module command-line option. If used, it specifies a module that should be imported early in the lifecycle of the interpreter, before site.py is executed. (Contributed by Łukasz Langa in gh-110769 [https://github.com/python/cpython/issues/110769].)

What’s New In Python 3.12

Editor:

Adam Turner

This article explains the new features in Python 3.12, compared to 3.11. Python 3.12 was released on October 2, 2023. For full details, see the changelog.

더 보기

PEP 693 [https://peps.python.org/pep-0693/] – Python 3.12 Release Schedule

Summary – Release highlights

Python 3.12 is a stable release of the Python programming language, with a mix of changes to the language and the standard library. The library changes focus on cleaning up deprecated APIs, usability, and correctness. Of note, the distutils package has been removed from the standard library. Filesystem support in os and pathlib has seen a number of improvements, and several modules have better performance.

The language changes focus on usability, as f-strings have had many limitations removed and ‘Did you mean …’ suggestions continue to improve. The new type parameter syntax and type statement improve ergonomics for using generic types and type aliases with static type checkers.

This article doesn’t attempt to provide a complete specification of all new features, but instead gives a convenient overview. For full details, you should refer to the documentation, such as the Library Reference and Language Reference. If you want to understand the complete implementation and design rationale for a change, refer to the PEP for a particular new feature; but note that PEPs usually are not kept up-to-date once a feature has been fully implemented.

New syntax features:

PEP 695, type parameter syntax and the type statement

New grammar features:

PEP 701, f-strings in the grammar

Interpreter improvements:

PEP 684, a unique per-interpreter GIL

PEP 669, low impact monitoring

Improved ‘Did you mean …’ suggestions for NameError, ImportError, and SyntaxError exceptions

Python data model improvements:

PEP 688, using the buffer protocol from Python

Significant improvements in the standard library:

The pathlib.Path class now supports subclassing

The os module received several improvements for Windows support

A command-line interface has been added to the sqlite3 module

isinstance() checks against runtime-checkable protocols enjoy a speed up of between two and 20 times

The asyncio package has had a number of performance improvements, with some benchmarks showing a 75% speed up.

A command-line interface has been added to the uuid module

Due to the changes in PEP 701, producing tokens via the tokenize module is up to 64% faster.

Security improvements:

Replace the builtin hashlib implementations of SHA1, SHA3, SHA2-384, SHA2-512, and MD5 with formally verified code from the HACL* [https://github.com/hacl-star/hacl-star/] project. These builtin implementations remain as fallbacks that are only used when OpenSSL does not provide them.

C API improvements:

PEP 697, unstable C API tier

PEP 683, immortal objects

CPython implementation improvements:

PEP 709, comprehension inlining

CPython support for the Linux perf profiler

Implement stack overflow protection on supported platforms

New typing features:

PEP 692, using TypedDict to annotate **kwargs

PEP 698, typing.override() decorator

Important deprecations, removals or restrictions:

PEP 623 [https://peps.python.org/pep-0623/]: Remove wstr from Unicode objects in Python’s C API, reducing the size of every str object by at least 8 bytes.

PEP 632 [https://peps.python.org/pep-0632/]: Remove the distutils package. See the migration guide [https://peps.python.org/pep-0632/#migration-advice] for advice replacing the APIs it provided. The third-party Setuptools [https://setuptools.pypa.io/en/latest/deprecated/distutils-legacy.html] package continues to provide distutils, if you still require it in Python 3.12 and beyond.

gh-95299 [https://github.com/python/cpython/issues/95299]: Do not pre-install setuptools in virtual environments created with venv. This means that distutils, setuptools, pkg_resources, and easy_install will no longer available by default; to access these run pip install setuptools in the activated virtual environment.

The asynchat, asyncore, and imp modules have been removed, along with several unittest.TestCase method aliases.

New Features

PEP 695: Type Parameter Syntax

Generic classes and functions under PEP 484 [https://peps.python.org/pep-0484/] were declared using a verbose syntax that left the scope of type parameters unclear and required explicit declarations of variance.

PEP 695 [https://peps.python.org/pep-0695/] introduces a new, more compact and explicit way to create generic classes and functions:

def max[T](args: Iterable[T]) -> T:
    ...

class list[T]:
    def __getitem__(self, index: int, /) -> T:
        ...

    def append(self, element: T) -> None:
        ...

In addition, the PEP introduces a new way to declare type aliases using the type statement, which creates an instance of TypeAliasType:

type Point = tuple[float, float]

Type aliases can also be generic:

type Point[T] = tuple[T, T]

The new syntax allows declaring TypeVarTuple and ParamSpec parameters, as well as TypeVar parameters with bounds or constraints:

type IntFunc[**P] = Callable[P, int]  # ParamSpec
type LabeledTuple[*Ts] = tuple[str, *Ts]  # TypeVarTuple
type HashableSequence[T: Hashable] = Sequence[T]  # TypeVar with bound
type IntOrStrSequence[T: (int, str)] = Sequence[T]  # TypeVar with constraints

The value of type aliases and the bound and constraints of type variables created through this syntax are evaluated only on demand (see lazy evaluation). This means type aliases are able to refer to other types defined later in the file.

Type parameters declared through a type parameter list are visible within the scope of the declaration and any nested scopes, but not in the outer scope. For example, they can be used in the type annotations for the methods of a generic class or in the class body. However, they cannot be used in the module scope after the class is defined. See Type parameter lists for a detailed description of the runtime semantics of type parameters.

In order to support these scoping semantics, a new kind of scope is introduced, the annotation scope. Annotation scopes behave for the most part like function scopes, but interact differently with enclosing class scopes. In Python 3.13, annotations will also be evaluated in annotation scopes.

See PEP 695 [https://peps.python.org/pep-0695/] for more details.

(PEP written by Eric Traut. Implementation by Jelle Zijlstra, Eric Traut, and others in gh-103764 [https://github.com/python/cpython/issues/103764].)

PEP 701: Syntactic formalization of f-strings

PEP 701 [https://peps.python.org/pep-0701/] lifts some restrictions on the usage of f-strings. Expression components inside f-strings can now be any valid Python expression, including strings reusing the same quote as the containing f-string, multi-line expressions, comments, backslashes, and unicode escape sequences. Let’s cover these in detail:

Quote reuse: in Python 3.11, reusing the same quotes as the enclosing f-string raises a SyntaxError, forcing the user to either use other available quotes (like using double quotes or triple quotes if the f-string uses single quotes). In Python 3.12, you can now do things like this:

>>> songs = ['Take me back to Eden', 'Alkaline', 'Ascensionism']
>>> f"This is the playlist: {", ".join(songs)}"
'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

Note that before this change there was no explicit limit in how f-strings can be nested, but the fact that string quotes cannot be reused inside the expression component of f-strings made it impossible to nest f-strings arbitrarily. In fact, this is the most nested f-string that could be written:

>>> f"""{f'''{f'{f"{1+1}"}'}'''}"""
'2'

As now f-strings can contain any valid Python expression inside expression components, it is now possible to nest f-strings arbitrarily:

>>> f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"
'2'

Multi-line expressions and comments: In Python 3.11, f-string expressions must be defined in a single line, even if the expression within the f-string could normally span multiple lines (like literal lists being defined over multiple lines), making them harder to read. In Python 3.12 you can now define f-strings spanning multiple lines, and add inline comments:

>>> f"This is the playlist: {", ".join([
...     'Take me back to Eden',  # My, my, those eyes like fire
...     'Alkaline',              # Not acid nor alkaline
...     'Ascensionism'           # Take to the broken skies at last
... ])}"
'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

Backslashes and unicode characters: before Python 3.12 f-string expressions couldn’t contain any \ character. This also affected unicode escape sequences (such as \N{snowman}) as these contain the \N part that previously could not be part of expression components of f-strings. Now, you can define expressions like this:

>>> print(f"This is the playlist: {"\n".join(songs)}")
This is the playlist: Take me back to Eden
Alkaline
Ascensionism
>>> print(f"This is the playlist: {"\N{BLACK HEART SUIT}".join(songs)}")
This is the playlist: Take me back to Eden♥Alkaline♥Ascensionism

See PEP 701 [https://peps.python.org/pep-0701/] for more details.

As a positive side-effect of how this feature has been implemented (by parsing f-strings with the PEG parser [https://peps.python.org/pep-0617/]), now error messages for f-strings are more precise and include the exact location of the error. For example, in Python 3.11, the following f-string raises a SyntaxError:

>>> my_string = f"{x z y}" + f"{1 + 1}"
  File "<stdin>", line 1
    (x z y)
     ^^^
SyntaxError: f-string: invalid syntax. Perhaps you forgot a comma?

but the error message doesn’t include the exact location of the error within the line and also has the expression artificially surrounded by parentheses. In Python 3.12, as f-strings are parsed with the PEG parser, error messages can be more precise and show the entire line:

>>> my_string = f"{x z y}" + f"{1 + 1}"
  File "<stdin>", line 1
    my_string = f"{x z y}" + f"{1 + 1}"
                   ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

(Contributed by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou, Cristián Maureira-Fredes and Marta Gómez in gh-102856 [https://github.com/python/cpython/issues/102856]. PEP written by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou and Marta Gómez).

PEP 684: A Per-Interpreter GIL

PEP 684 [https://peps.python.org/pep-0684/] introduces a per-interpreter GIL, so that sub-interpreters may now be created with a unique GIL per interpreter. This allows Python programs to take full advantage of multiple CPU cores. This is currently only available through the C-API, though a Python API is anticipated for 3.13 [https://peps.python.org/pep-0554/].

Use the new Py_NewInterpreterFromConfig() function to create an interpreter with its own GIL:

PyInterpreterConfig config = {
    .check_multi_interp_extensions = 1,
    .gil = PyInterpreterConfig_OWN_GIL,
};
PyThreadState *tstate = NULL;
PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
if (PyStatus_Exception(status)) {
    return -1;
}
/* The new interpreter is now active in the current thread. */

For further examples how to use the C-API for sub-interpreters with a per-interpreter GIL, see Modules/_xxsubinterpretersmodule.c.

(Contributed by Eric Snow in gh-104210 [https://github.com/python/cpython/issues/104210], etc.)

PEP 669: Low impact monitoring for CPython

PEP 669 [https://peps.python.org/pep-0669/] defines a new API for profilers, debuggers, and other tools to monitor events in CPython. It covers a wide range of events, including calls, returns, lines, exceptions, jumps, and more. This means that you only pay for what you use, providing support for near-zero overhead debuggers and coverage tools. See sys.monitoring for details.

(Contributed by Mark Shannon in gh-103082 [https://github.com/python/cpython/issues/103082].)

PEP 688: Making the buffer protocol accessible in Python

PEP 688 [https://peps.python.org/pep-0688/] introduces a way to use the buffer protocol from Python code. Classes that implement the __buffer__() method are now usable as buffer types.

The new collections.abc.Buffer ABC provides a standard way to represent buffer objects, for example in type annotations. The new inspect.BufferFlags enum represents the flags that can be used to customize buffer creation. (Contributed by Jelle Zijlstra in gh-102500 [https://github.com/python/cpython/issues/102500].)

PEP 709: Comprehension inlining

Dictionary, list, and set comprehensions are now inlined, rather than creating a new single-use function object for each execution of the comprehension. This speeds up execution of a comprehension by up to two times. See PEP 709 [https://peps.python.org/pep-0709/] for further details.

Comprehension iteration variables remain isolated and don’t overwrite a variable of the same name in the outer scope, nor are they visible after the comprehension. Inlining does result in a few visible behavior changes:

There is no longer a separate frame for the comprehension in tracebacks, and tracing/profiling no longer shows the comprehension as a function call.

The symtable module will no longer produce child symbol tables for each comprehension; instead, the comprehension’s locals will be included in the parent function’s symbol table.

Calling locals() inside a comprehension now includes variables from outside the comprehension, and no longer includes the synthetic .0 variable for the comprehension “argument”.

A comprehension iterating directly over locals() (e.g. [k for k in locals()]) may see “RuntimeError: dictionary changed size during iteration” when run under tracing (e.g. code coverage measurement). This is the same behavior already seen in e.g. for k in locals():. To avoid the error, first create a list of keys to iterate over: keys = list(locals()); [k for k in keys].

(Contributed by Carl Meyer and Vladimir Matveev in PEP 709 [https://peps.python.org/pep-0709/].)

Improved Error Messages

Modules from the standard library are now potentially suggested as part of the error messages displayed by the interpreter when a NameError is raised to the top level. (Contributed by Pablo Galindo in gh-98254 [https://github.com/python/cpython/issues/98254].)

>>> sys.version_info
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'sys' is not defined. Did you forget to import 'sys'?

Improve the error suggestion for NameError exceptions for instances. Now if a NameError is raised in a method and the instance has an attribute that’s exactly equal to the name in the exception, the suggestion will include self.<NAME> instead of the closest match in the method scope. (Contributed by Pablo Galindo in gh-99139 [https://github.com/python/cpython/issues/99139].)

>>> class A:
...    def __init__(self):
...        self.blech = 1
...
...    def foo(self):
...        somethin = blech
...
>>> A().foo()
Traceback (most recent call last):
  File "<stdin>", line 1
    somethin = blech
               ^^^^^
NameError: name 'blech' is not defined. Did you mean: 'self.blech'?

Improve the SyntaxError error message when the user types import x from y instead of from y import x. (Contributed by Pablo Galindo in gh-98931 [https://github.com/python/cpython/issues/98931].)

>>> import a.y.z from b.y.z
Traceback (most recent call last):
  File "<stdin>", line 1
    import a.y.z from b.y.z
    ^^^^^^^^^^^^^^^^^^^^^^^
SyntaxError: Did you mean to use 'from ... import ...' instead?

ImportError exceptions raised from failed from <module> import <name> statements now include suggestions for the value of <name> based on the available names in <module>. (Contributed by Pablo Galindo in gh-91058 [https://github.com/python/cpython/issues/91058].)

>>> from collections import chainmap
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name 'chainmap' from 'collections'. Did you mean: 'ChainMap'?

New Features Related to Type Hints

This section covers major changes affecting type hints [https://peps.python.org/pep-0484/] and the typing module.

PEP 692: Using TypedDict for more precise **kwargs typing

Typing **kwargs in a function signature as introduced by PEP 484 [https://peps.python.org/pep-0484/] allowed for valid annotations only in cases where all of the **kwargs were of the same type.

PEP 692 [https://peps.python.org/pep-0692/] specifies a more precise way of typing **kwargs by relying on typed dictionaries:

from typing import TypedDict, Unpack

class Movie(TypedDict):
  name: str
  year: int

def foo(**kwargs: Unpack[Movie]): ...

See PEP 692 [https://peps.python.org/pep-0692/] for more details.

(Contributed by Franek Magiera in gh-103629 [https://github.com/python/cpython/issues/103629].)

PEP 698: Override Decorator for Static Typing

A new decorator typing.override() has been added to the typing module. It indicates to type checkers that the method is intended to override a method in a superclass. This allows type checkers to catch mistakes where a method that is intended to override something in a base class does not in fact do so.

Example:

from typing import override

class Base:
  def get_color(self) -> str:
    return "blue"

class GoodChild(Base):
  @override  # ok: overrides Base.get_color
  def get_color(self) -> str:
    return "yellow"

class BadChild(Base):
  @override  # type checker error: does not override Base.get_color
  def get_colour(self) -> str:
    return "red"

See PEP 698 [https://peps.python.org/pep-0698/] for more details.

(Contributed by Steven Troxler in gh-101561 [https://github.com/python/cpython/issues/101561].)

Other Language Changes

The parser now raises SyntaxError when parsing source code containing null bytes. (Contributed by Pablo Galindo in gh-96670 [https://github.com/python/cpython/issues/96670].)

A backslash-character pair that is not a valid escape sequence now generates a SyntaxWarning, instead of DeprecationWarning. For example, re.compile("\d+\.\d+") now emits a SyntaxWarning ("\d" is an invalid escape sequence, use raw strings for regular expression: re.compile(r"\d+\.\d+")). In a future Python version, SyntaxError will eventually be raised, instead of SyntaxWarning. (Contributed by Victor Stinner in gh-98401 [https://github.com/python/cpython/issues/98401].)

Octal escapes with value larger than 0o377 (ex: "\477"), deprecated in Python 3.11, now produce a SyntaxWarning, instead of DeprecationWarning. In a future Python version they will be eventually a SyntaxError. (Contributed by Victor Stinner in gh-98401 [https://github.com/python/cpython/issues/98401].)

Variables used in the target part of comprehensions that are not stored to can now be used in assignment expressions (:=). For example, in [(b := 1) for a, b.prop in some_iter], the assignment to b is now allowed. Note that assigning to variables stored to in the target part of comprehensions (like a) is still disallowed, as per PEP 572 [https://peps.python.org/pep-0572/]. (Contributed by Nikita Sobolev in gh-100581 [https://github.com/python/cpython/issues/100581].)

Exceptions raised in a class or type’s __set_name__ method are no longer wrapped by a RuntimeError. Context information is added to the exception as a PEP 678 [https://peps.python.org/pep-0678/] note. (Contributed by Irit Katriel in gh-77757 [https://github.com/python/cpython/issues/77757].)

When a try-except* construct handles the entire ExceptionGroup and raises one other exception, that exception is no longer wrapped in an ExceptionGroup. Also changed in version 3.11.4. (Contributed by Irit Katriel in gh-103590 [https://github.com/python/cpython/issues/103590].)

The Garbage Collector now runs only on the eval breaker mechanism of the Python bytecode evaluation loop instead of object allocations. The GC can also run when PyErr_CheckSignals() is called so C extensions that need to run for a long time without executing any Python code also have a chance to execute the GC periodically. (Contributed by Pablo Galindo in gh-97922 [https://github.com/python/cpython/issues/97922].)

All builtin and extension callables expecting boolean parameters now accept arguments of any type instead of just bool and int. (Contributed by Serhiy Storchaka in gh-60203 [https://github.com/python/cpython/issues/60203].)

memoryview now supports the half-float type (the “e” format code). (Contributed by Donghee Na and Antoine Pitrou in gh-90751 [https://github.com/python/cpython/issues/90751].)

slice objects are now hashable, allowing them to be used as dict keys and set items. (Contributed by Will Bradshaw, Furkan Onder, and Raymond Hettinger in gh-101264 [https://github.com/python/cpython/issues/101264].)

sum() now uses Neumaier summation to improve accuracy and commutativity when summing floats or mixed ints and floats. (Contributed by Raymond Hettinger in gh-100425 [https://github.com/python/cpython/issues/100425].)

ast.parse() now raises SyntaxError instead of ValueError when parsing source code containing null bytes. (Contributed by Pablo Galindo in gh-96670 [https://github.com/python/cpython/issues/96670].)

The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See tarfile extraction filters for details. In Python 3.14, the default will switch to 'data'. (Contributed by Petr Viktorin in PEP 706 [https://peps.python.org/pep-0706/].)

types.MappingProxyType instances are now hashable if the underlying mapping is hashable. (Contributed by Serhiy Storchaka in gh-87995 [https://github.com/python/cpython/issues/87995].)

Add support for the perf profiler through the new environment variable PYTHONPERFSUPPORT and command-line option -X perf, as well as the new sys.activate_stack_trampoline(), sys.deactivate_stack_trampoline(), and sys.is_stack_trampoline_active() functions. (Design by Pablo Galindo. Contributed by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith [Google] and Mark Shannon in gh-96123 [https://github.com/python/cpython/issues/96123].)

New Modules

None.

Improved Modules

array

The array.array class now supports subscripting, making it a generic type. (Contributed by Jelle Zijlstra in gh-98658 [https://github.com/python/cpython/issues/98658].)

asyncio

The performance of writing to sockets in asyncio has been significantly improved. asyncio now avoids unnecessary copying when writing to sockets and uses sendmsg() if the platform supports it. (Contributed by Kumar Aditya in gh-91166 [https://github.com/python/cpython/issues/91166].)

Add asyncio.eager_task_factory() and asyncio.create_eager_task_factory() functions to allow opting an event loop in to eager task execution, making some use-cases 2x to 5x faster. (Contributed by Jacob Bower & Itamar Oren in gh-102853 [https://github.com/python/cpython/issues/102853], gh-104140 [https://github.com/python/cpython/issues/104140], and gh-104138 [https://github.com/python/cpython/issues/104138])

On Linux, asyncio uses asyncio.PidfdChildWatcher by default if os.pidfd_open() is available and functional instead of asyncio.ThreadedChildWatcher. (Contributed by Kumar Aditya in gh-98024 [https://github.com/python/cpython/issues/98024].)

The event loop now uses the best available child watcher for each platform (asyncio.PidfdChildWatcher if supported and asyncio.ThreadedChildWatcher otherwise), so manually configuring a child watcher is not recommended. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

Add loop_factory parameter to asyncio.run() to allow specifying a custom event loop factory. (Contributed by Kumar Aditya in gh-99388 [https://github.com/python/cpython/issues/99388].)

Add C implementation of asyncio.current_task() for 4x-6x speedup. (Contributed by Itamar Oren and Pranav Thulasiram Bhat in gh-100344 [https://github.com/python/cpython/issues/100344].)

asyncio.iscoroutine() now returns False for generators as asyncio does not support legacy generator-based coroutines. (Contributed by Kumar Aditya in gh-102748 [https://github.com/python/cpython/issues/102748].)

asyncio.wait() and asyncio.as_completed() now accepts generators yielding tasks. (Contributed by Kumar Aditya in gh-78530 [https://github.com/python/cpython/issues/78530].)

calendar

Add enums calendar.Month and calendar.Day defining months of the year and days of the week. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

csv

Add csv.QUOTE_NOTNULL and csv.QUOTE_STRINGS flags to provide finer grained control of None and empty strings by reader and writer objects.

dis

Pseudo instruction opcodes (which are used by the compiler but do not appear in executable bytecode) are now exposed in the dis module. HAVE_ARGUMENT is still relevant to real opcodes, but it is not useful for pseudo instructions. Use the new dis.hasarg collection instead. (Contributed by Irit Katriel in gh-94216 [https://github.com/python/cpython/issues/94216].)

Add the dis.hasexc collection to signify instructions that set an exception handler. (Contributed by Irit Katriel in gh-94216 [https://github.com/python/cpython/issues/94216].)

fractions

Objects of type fractions.Fraction now support float-style formatting. (Contributed by Mark Dickinson in gh-100161 [https://github.com/python/cpython/issues/100161].)

importlib.resources

importlib.resources.as_file() now supports resource directories. (Contributed by Jason R. Coombs in gh-97930 [https://github.com/python/cpython/issues/97930].)

Rename first parameter of importlib.resources.files() to anchor. (Contributed by Jason R. Coombs in gh-100598 [https://github.com/python/cpython/issues/100598].)

inspect

Add inspect.markcoroutinefunction() to mark sync functions that return a coroutine for use with inspect.iscoroutinefunction(). (Contributed by Carlton Gibson in gh-99247 [https://github.com/python/cpython/issues/99247].)

Add inspect.getasyncgenstate() and inspect.getasyncgenlocals() for determining the current state of asynchronous generators. (Contributed by Thomas Krennwallner in gh-79940 [https://github.com/python/cpython/issues/79940].)

The performance of inspect.getattr_static() has been considerably improved. Most calls to the function should be at least 2x faster than they were in Python 3.11. (Contributed by Alex Waygood in gh-103193 [https://github.com/python/cpython/issues/103193].)

itertools

Add itertools.batched() for collecting into even-sized tuples where the last batch may be shorter than the rest. (Contributed by Raymond Hettinger in gh-98363 [https://github.com/python/cpython/issues/98363].)

math

Add math.sumprod() for computing a sum of products. (Contributed by Raymond Hettinger in gh-100485 [https://github.com/python/cpython/issues/100485].)

Extend math.nextafter() to include a steps argument for moving up or down multiple steps at a time. (Contributed by Matthias Goergens, Mark Dickinson, and Raymond Hettinger in gh-94906 [https://github.com/python/cpython/issues/94906].)

os

Add os.PIDFD_NONBLOCK to open a file descriptor for a process with os.pidfd_open() in non-blocking mode. (Contributed by Kumar Aditya in gh-93312 [https://github.com/python/cpython/issues/93312].)

os.DirEntry now includes an os.DirEntry.is_junction() method to check if the entry is a junction. (Contributed by Charles Machalow in gh-99547 [https://github.com/python/cpython/issues/99547].)

Add os.listdrives(), os.listvolumes() and os.listmounts() functions on Windows for enumerating drives, volumes and mount points. (Contributed by Steve Dower in gh-102519 [https://github.com/python/cpython/issues/102519].)

os.stat() and os.lstat() are now more accurate on Windows. The st_birthtime field will now be filled with the creation time of the file, and st_ctime is deprecated but still contains the creation time (but in the future will return the last metadata change, for consistency with other platforms). st_dev may be up to 64 bits and st_ino up to 128 bits depending on your file system, and st_rdev is always set to zero rather than incorrect values. Both functions may be significantly faster on newer releases of Windows. (Contributed by Steve Dower in gh-99726 [https://github.com/python/cpython/issues/99726].)

os.path

Add os.path.isjunction() to check if a given path is a junction. (Contributed by Charles Machalow in gh-99547 [https://github.com/python/cpython/issues/99547].)

Add os.path.splitroot() to split a path into a triad (drive, root, tail). (Contributed by Barney Gale in gh-101000 [https://github.com/python/cpython/issues/101000].)

pathlib

Add support for subclassing pathlib.PurePath and pathlib.Path, plus their Posix- and Windows-specific variants. Subclasses may override the pathlib.PurePath.with_segments() method to pass information between path instances.

Add pathlib.Path.walk() for walking the directory trees and generating all file or directory names within them, similar to os.walk(). (Contributed by Stanislav Zmiev in gh-90385 [https://github.com/python/cpython/issues/90385].)

Add walk_up optional parameter to pathlib.PurePath.relative_to() to allow the insertion of .. entries in the result; this behavior is more consistent with os.path.relpath(). (Contributed by Domenico Ragusa in gh-84538 [https://github.com/python/cpython/issues/84538].)

Add pathlib.Path.is_junction() as a proxy to os.path.isjunction(). (Contributed by Charles Machalow in gh-99547 [https://github.com/python/cpython/issues/99547].)

Add case_sensitive optional parameter to pathlib.Path.glob(), pathlib.Path.rglob() and pathlib.PurePath.match() for matching the path’s case sensitivity, allowing for more precise control over the matching process.

pdb

Add convenience variables to hold values temporarily for debug session and provide quick access to values like the current frame or the return value. (Contributed by Tian Gao in gh-103693 [https://github.com/python/cpython/issues/103693].)

random

Add random.binomialvariate(). (Contributed by Raymond Hettinger in gh-81620 [https://github.com/python/cpython/issues/81620].)

Add a default of lambd=1.0 to random.expovariate(). (Contributed by Raymond Hettinger in gh-100234 [https://github.com/python/cpython/issues/100234].)

shutil

shutil.make_archive() now passes the root_dir argument to custom archivers which support it. In this case it no longer temporarily changes the current working directory of the process to root_dir to perform archiving. (Contributed by Serhiy Storchaka in gh-74696 [https://github.com/python/cpython/issues/74696].)

shutil.rmtree() now accepts a new argument onexc which is an error handler like onerror but which expects an exception instance rather than a (typ, val, tb) triplet. onerror is deprecated. (Contributed by Irit Katriel in gh-102828 [https://github.com/python/cpython/issues/102828].)

shutil.which() now consults the PATHEXT environment variable to find matches within PATH on Windows even when the given cmd includes a directory component. (Contributed by Charles Machalow in gh-103179 [https://github.com/python/cpython/issues/103179].)

shutil.which() will call NeedCurrentDirectoryForExePathW when querying for executables on Windows to determine if the current working directory should be prepended to the search path. (Contributed by Charles Machalow in gh-103179 [https://github.com/python/cpython/issues/103179].)

shutil.which() will return a path matching the cmd with a component from PATHEXT prior to a direct match elsewhere in the search path on Windows. (Contributed by Charles Machalow in gh-103179 [https://github.com/python/cpython/issues/103179].)

sqlite3

Add a command-line interface. (Contributed by Erlend E. Aasland in gh-77617 [https://github.com/python/cpython/issues/77617].)

Add the sqlite3.Connection.autocommit attribute to sqlite3.Connection and the autocommit parameter to sqlite3.connect() to control PEP 249 [https://peps.python.org/pep-0249/]-compliant transaction handling. (Contributed by Erlend E. Aasland in gh-83638 [https://github.com/python/cpython/issues/83638].)

Add entrypoint keyword-only parameter to sqlite3.Connection.load_extension(), for overriding the SQLite extension entry point. (Contributed by Erlend E. Aasland in gh-103015 [https://github.com/python/cpython/issues/103015].)

Add sqlite3.Connection.getconfig() and sqlite3.Connection.setconfig() to sqlite3.Connection to make configuration changes to a database connection. (Contributed by Erlend E. Aasland in gh-103489 [https://github.com/python/cpython/issues/103489].)

statistics

Extend statistics.correlation() to include as a ranked method for computing the Spearman correlation of ranked data. (Contributed by Raymond Hettinger in gh-95861 [https://github.com/python/cpython/issues/95861].)

sys

Add the sys.monitoring namespace to expose the new PEP 669 monitoring API. (Contributed by Mark Shannon in gh-103082 [https://github.com/python/cpython/issues/103082].)

Add sys.activate_stack_trampoline() and sys.deactivate_stack_trampoline() for activating and deactivating stack profiler trampolines, and sys.is_stack_trampoline_active() for querying if stack profiler trampolines are active. (Contributed by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith [Google] and Mark Shannon in gh-96123 [https://github.com/python/cpython/issues/96123].)

Add sys.last_exc which holds the last unhandled exception that was raised (for post-mortem debugging use cases). Deprecate the three fields that have the same information in its legacy form: sys.last_type, sys.last_value and sys.last_traceback. (Contributed by Irit Katriel in gh-102778 [https://github.com/python/cpython/issues/102778].)

sys._current_exceptions() now returns a mapping from thread-id to an exception instance, rather than to a (typ, exc, tb) tuple. (Contributed by Irit Katriel in gh-103176 [https://github.com/python/cpython/issues/103176].)

sys.setrecursionlimit() and sys.getrecursionlimit(). The recursion limit now applies only to Python code. Builtin functions do not use the recursion limit, but are protected by a different mechanism that prevents recursion from causing a virtual machine crash.

tempfile

The tempfile.NamedTemporaryFile function has a new optional parameter delete_on_close (Contributed by Evgeny Zorin in gh-58451 [https://github.com/python/cpython/issues/58451].)

tempfile.mkdtemp() now always returns an absolute path, even if the argument provided to the dir parameter is a relative path.

threading

Add threading.settrace_all_threads() and threading.setprofile_all_threads() that allow to set tracing and profiling functions in all running threads in addition to the calling one. (Contributed by Pablo Galindo in gh-93503 [https://github.com/python/cpython/issues/93503].)

tkinter

tkinter.Canvas.coords() now flattens its arguments. It now accepts not only coordinates as separate arguments (x1, y1, x2, y2, ...) and a sequence of coordinates ([x1, y1, x2, y2, ...]), but also coordinates grouped in pairs ((x1, y1), (x2, y2), ... and [(x1, y1), (x2, y2), ...]), like create_*() methods. (Contributed by Serhiy Storchaka in gh-94473 [https://github.com/python/cpython/issues/94473].)

tokenize

The tokenize module includes the changes introduced in PEP 701 [https://peps.python.org/pep-0701/]. (Contributed by Marta Gómez Macías and Pablo Galindo in gh-102856 [https://github.com/python/cpython/issues/102856].) See Porting to Python 3.12 for more information on the changes to the tokenize module.

types

Add types.get_original_bases() to allow for further introspection of 사용자 정의 제네릭 형 when subclassed. (Contributed by James Hilton-Balfe and Alex Waygood in gh-101827 [https://github.com/python/cpython/issues/101827].)

typing

isinstance() checks against runtime-checkable protocols now use inspect.getattr_static() rather than hasattr() to lookup whether attributes exist. This means that descriptors and __getattr__() methods are no longer unexpectedly evaluated during isinstance() checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change. (Contributed by Alex Waygood in gh-102433 [https://github.com/python/cpython/issues/102433].)

The members of a runtime-checkable protocol are now considered “frozen” at runtime as soon as the class has been created. Monkey-patching attributes onto a runtime-checkable protocol will still work, but will have no impact on isinstance() checks comparing objects to the protocol. For example:

>>> from typing import Protocol, runtime_checkable
>>> @runtime_checkable
... class HasX(Protocol):
...     x = 1
...
>>> class Foo: ...
...
>>> f = Foo()
>>> isinstance(f, HasX)
False
>>> f.x = 1
>>> isinstance(f, HasX)
True
>>> HasX.y = 2
>>> isinstance(f, HasX)  # unchanged, even though HasX now also has a "y" attribute
True

This change was made in order to speed up isinstance() checks against runtime-checkable protocols.

The performance profile of isinstance() checks against runtime-checkable protocols has changed significantly. Most isinstance() checks against protocols with only a few members should be at least 2x faster than in 3.11, and some may be 20x faster or more. However, isinstance() checks against protocols with many members may be slower than in Python 3.11. (Contributed by Alex Waygood in gh-74690 [https://github.com/python/cpython/issues/74690] and gh-103193 [https://github.com/python/cpython/issues/103193].)

All typing.TypedDict and typing.NamedTuple classes now have the __orig_bases__ attribute. (Contributed by Adrian Garcia Badaracco in gh-103699 [https://github.com/python/cpython/issues/103699].)

Add frozen_default parameter to typing.dataclass_transform(). (Contributed by Erik De Bonte in gh-99957 [https://github.com/python/cpython/issues/99957].)

unicodedata

The Unicode database has been updated to version 15.0.0. (Contributed by Benjamin Peterson in gh-96734 [https://github.com/python/cpython/issues/96734]).

unittest

Add a --durations command line option, showing the N slowest test cases:

python3 -m unittest --durations=3 lib.tests.test_threading
.....
Slowest test durations
----------------------------------------------------------------------
1.210s     test_timeout (Lib.test.test_threading.BarrierTests)
1.003s     test_default_timeout (Lib.test.test_threading.BarrierTests)
0.518s     test_timeout (Lib.test.test_threading.EventTests)

(0.000 durations hidden.  Use -v to show these durations.)
----------------------------------------------------------------------
Ran 158 tests in 9.869s

OK (skipped=3)

(Contributed by Giampaolo Rodola in gh-48330 [https://github.com/python/cpython/issues/48330])

uuid

Add a command-line interface. (Contributed by Adam Chhina in gh-88597 [https://github.com/python/cpython/issues/88597].)

Optimizations

Remove wstr and wstr_length members from Unicode objects. It reduces object size by 8 or 16 bytes on 64bit platform. (PEP 623 [https://peps.python.org/pep-0623/]) (Contributed by Inada Naoki in gh-92536 [https://github.com/python/cpython/issues/92536].)

Add experimental support for using the BOLT binary optimizer in the build process, which improves performance by 1-5%. (Contributed by Kevin Modzelewski in gh-90536 [https://github.com/python/cpython/issues/90536] and tuned by Donghee Na in gh-101525 [https://github.com/python/cpython/issues/101525])

Speed up the regular expression substitution (functions re.sub() and re.subn() and corresponding re.Pattern methods) for replacement strings containing group references by 2–3 times. (Contributed by Serhiy Storchaka in gh-91524 [https://github.com/python/cpython/issues/91524].)

Speed up asyncio.Task creation by deferring expensive string formatting. (Contributed by Itamar Oren in gh-103793 [https://github.com/python/cpython/issues/103793].)

The tokenize.tokenize() and tokenize.generate_tokens() functions are up to 64% faster as a side effect of the changes required to cover PEP 701 [https://peps.python.org/pep-0701/] in the tokenize module. (Contributed by Marta Gómez Macías and Pablo Galindo in gh-102856 [https://github.com/python/cpython/issues/102856].)

Speed up super() method calls and attribute loads via the new LOAD_SUPER_ATTR instruction. (Contributed by Carl Meyer and Vladimir Matveev in gh-103497 [https://github.com/python/cpython/issues/103497].)

CPython bytecode changes

Remove the LOAD_METHOD instruction. It has been merged into LOAD_ATTR. LOAD_ATTR will now behave like the old LOAD_METHOD instruction if the low bit of its oparg is set. (Contributed by Ken Jin in gh-93429 [https://github.com/python/cpython/issues/93429].)

Remove the JUMP_IF_FALSE_OR_POP and JUMP_IF_TRUE_OR_POP instructions. (Contributed by Irit Katriel in gh-102859 [https://github.com/python/cpython/issues/102859].)

Remove the PRECALL instruction. (Contributed by Mark Shannon in gh-92925 [https://github.com/python/cpython/issues/92925].)

Add the BINARY_SLICE and STORE_SLICE instructions. (Contributed by Mark Shannon in gh-94163 [https://github.com/python/cpython/issues/94163].)

Add the CALL_INTRINSIC_1 instructions. (Contributed by Mark Shannon in gh-99005 [https://github.com/python/cpython/issues/99005].)

Add the CALL_INTRINSIC_2 instruction. (Contributed by Irit Katriel in gh-101799 [https://github.com/python/cpython/issues/101799].)

Add the CLEANUP_THROW instruction. (Contributed by Brandt Bucher in gh-90997 [https://github.com/python/cpython/issues/90997].)

Add the END_SEND instruction. (Contributed by Mark Shannon in gh-103082 [https://github.com/python/cpython/issues/103082].)

Add the LOAD_FAST_AND_CLEAR instruction as part of the implementation of PEP 709 [https://peps.python.org/pep-0709/]. (Contributed by Carl Meyer in gh-101441 [https://github.com/python/cpython/issues/101441].)

Add the LOAD_FAST_CHECK instruction. (Contributed by Dennis Sweeney in gh-93143 [https://github.com/python/cpython/issues/93143].)

Add the LOAD_FROM_DICT_OR_DEREF, LOAD_FROM_DICT_OR_GLOBALS, and LOAD_LOCALS opcodes as part of the implementation of PEP 695 [https://peps.python.org/pep-0695/]. Remove the LOAD_CLASSDEREF opcode, which can be replaced with LOAD_LOCALS plus LOAD_FROM_DICT_OR_DEREF. (Contributed by Jelle Zijlstra in gh-103764 [https://github.com/python/cpython/issues/103764].)

Add the LOAD_SUPER_ATTR instruction. (Contributed by Carl Meyer and Vladimir Matveev in gh-103497 [https://github.com/python/cpython/issues/103497].)

Add the RETURN_CONST instruction. (Contributed by Wenyang Wang in gh-101632 [https://github.com/python/cpython/issues/101632].)

Demos and Tools

Remove the Tools/demo/ directory which contained old demo scripts. A copy can be found in the old-demos project [https://github.com/gvanrossum/old-demos]. (Contributed by Victor Stinner in gh-97681 [https://github.com/python/cpython/issues/97681].)

Remove outdated example scripts of the Tools/scripts/ directory. A copy can be found in the old-demos project [https://github.com/gvanrossum/old-demos]. (Contributed by Victor Stinner in gh-97669 [https://github.com/python/cpython/issues/97669].)

Deprecated

argparse: The type, choices, and metavar parameters of argparse.BooleanOptionalAction are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in gh-92248 [https://github.com/python/cpython/issues/92248].)

ast: The following ast features have been deprecated in documentation since Python 3.8, now cause a DeprecationWarning to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

ast.Num

ast.Str

ast.Bytes

ast.NameConstant

ast.Ellipsis

Use ast.Constant instead. (Contributed by Serhiy Storchaka in gh-90953 [https://github.com/python/cpython/issues/90953].)

asyncio:

The child watcher classes asyncio.MultiLoopChildWatcher, asyncio.FastChildWatcher, asyncio.AbstractChildWatcher and asyncio.SafeChildWatcher are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

asyncio.set_child_watcher(), asyncio.get_child_watcher(), asyncio.AbstractEventLoopPolicy.set_child_watcher() and asyncio.AbstractEventLoopPolicy.get_child_watcher() are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

The get_event_loop() method of the default event loop policy now emits a DeprecationWarning if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in gh-100160 [https://github.com/python/cpython/issues/100160].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

collections.abc: Deprecated collections.abc.ByteString. Prefer Sequence or collections.abc.Buffer. For use in typing, prefer a union, like bytes | bytearray, or collections.abc.Buffer. (Contributed by Shantanu Jain in gh-91896 [https://github.com/python/cpython/issues/91896].)

datetime: datetime.datetime’s utcnow() and utcfromtimestamp() are deprecated and will be removed in a future version. Instead, use timezone-aware objects to represent datetimes in UTC: respectively, call now() and fromtimestamp() with the tz parameter set to datetime.UTC. (Contributed by Paul Ganssle in gh-103857 [https://github.com/python/cpython/issues/103857].)

email: Deprecate the isdst parameter in email.utils.localtime(). (Contributed by Alan Williams in gh-72346 [https://github.com/python/cpython/issues/72346].)

importlib.abc: Deprecated the following classes, scheduled for removal in Python 3.14:

importlib.abc.ResourceReader

importlib.abc.Traversable

importlib.abc.TraversableResources

Use importlib.resources.abc classes instead:

importlib.resources.abc.Traversable

importlib.resources.abc.TraversableResources

(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963 [https://github.com/python/cpython/issues/93963].)

itertools: Deprecate the support for copy, deepcopy, and pickle operations, which is undocumented, inefficient, historically buggy, and inconsistent. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in gh-101588 [https://github.com/python/cpython/issues/101588].)

multiprocessing: In Python 3.14, the default multiprocessing start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where 'fork' is currently the default (gh-84559 [https://github.com/python/cpython/issues/84559]). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the get_context() or set_start_method() APIs to explicitly specify when your code requires 'fork'. See contexts and start methods.

pkgutil: pkgutil.find_loader() and pkgutil.get_loader() are deprecated and will be removed in Python 3.14; use importlib.util.find_spec() instead. (Contributed by Nikita Sobolev in gh-97850 [https://github.com/python/cpython/issues/97850].)

pty: The module has two undocumented master_open() and slave_open() functions that have been deprecated since Python 2 but only gained a proper DeprecationWarning in 3.12. Remove them in 3.14. (Contributed by Soumendra Ganguly and Gregory P. Smith in gh-85984 [https://github.com/python/cpython/issues/85984].)

os:

The st_ctime fields return by os.stat() and os.lstat() on Windows are deprecated. In a future release, they will contain the last metadata change time, consistent with other platforms. For now, they still contain the creation time, which is also available in the new st_birthtime field. (Contributed by Steve Dower in gh-99726 [https://github.com/python/cpython/issues/99726].)

On POSIX platforms, os.fork() can now raise a DeprecationWarning when it can detect being called from a multithreaded process. There has always been a fundamental incompatibility with the POSIX platform when doing so. Even if such code appeared to work. We added the warning to raise awareness as issues encountered by code doing this are becoming more frequent. See the os.fork() documentation for more details along with this discussion on fork being incompatible with threads [https://discuss.python.org/t/concerns-regarding-deprecation-of-fork-with-alive-threads/33555] for why we’re now surfacing this longstanding platform compatibility problem to developers.

When this warning appears due to usage of multiprocessing or concurrent.futures the fix is to use a different multiprocessing start method such as "spawn" or "forkserver".

shutil: The onerror argument of shutil.rmtree() is deprecated; use onexc instead. (Contributed by Irit Katriel in gh-102828 [https://github.com/python/cpython/issues/102828].)

sqlite3:

default adapters and converters are now deprecated. Instead, use the Adapter and converter recipes and tailor them to your needs. (Contributed by Erlend E. Aasland in gh-90016 [https://github.com/python/cpython/issues/90016].)

In execute(), DeprecationWarning is now emitted when named placeholders are used together with parameters supplied as a sequence instead of as a dict. Starting from Python 3.14, using named placeholders with parameters supplied as a sequence will raise a ProgrammingError. (Contributed by Erlend E. Aasland in gh-101698 [https://github.com/python/cpython/issues/101698].)

sys: The sys.last_type, sys.last_value and sys.last_traceback fields are deprecated. Use sys.last_exc instead. (Contributed by Irit Katriel in gh-102778 [https://github.com/python/cpython/issues/102778].)

tarfile: Extracting tar archives without specifying filter is deprecated until Python 3.14, when 'data' filter will become the default. See Extraction filters for details.

typing:

typing.Hashable and typing.Sized, aliases for collections.abc.Hashable and collections.abc.Sized respectively, are deprecated. (gh-94309 [https://github.com/python/cpython/issues/94309].)

typing.ByteString, deprecated since Python 3.9, now causes a DeprecationWarning to be emitted when it is used. (Contributed by Alex Waygood in gh-91896 [https://github.com/python/cpython/issues/91896].)

xml.etree.ElementTree: The module now emits DeprecationWarning when testing the truth value of an xml.etree.ElementTree.Element. Before, the Python implementation emitted FutureWarning, and the C implementation emitted nothing. (Contributed by Jacob Walls in gh-83122 [https://github.com/python/cpython/issues/83122].)

The 3-arg signatures (type, value, traceback) of coroutine throw(), generator throw() and async generator throw() are deprecated and may be removed in a future version of Python. Use the single-arg versions of these functions instead. (Contributed by Ofey Chan in gh-89874 [https://github.com/python/cpython/issues/89874].)

DeprecationWarning is now raised when __package__ on a module differs from __spec__.parent (previously it was ImportWarning). (Contributed by Brett Cannon in gh-65961 [https://github.com/python/cpython/issues/65961].)

Setting __package__ or __cached__ on a module is deprecated, and will cease to be set or taken into consideration by the import system in Python 3.14. (Contributed by Brett Cannon in gh-65961 [https://github.com/python/cpython/issues/65961].)

The bitwise inversion operator (~) on bool is deprecated. It will throw an error in Python 3.16. Use not for logical negation of bools instead. In the rare case that you really need the bitwise inversion of the underlying int, convert to int explicitly: ~int(x). (Contributed by Tim Hoffmann in gh-103487 [https://github.com/python/cpython/issues/103487].)

Accessing co_lnotab on code objects was deprecated in Python 3.10 via PEP 626 [https://peps.python.org/pep-0626/], but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

Pending removal in Python 3.13

Modules (see PEP 594 [https://peps.python.org/pep-0594/]):

aifc

audioop

cgi

cgitb

chunk

crypt

imghdr

mailcap

msilib

nis

nntplib

ossaudiodev

pipes

sndhdr

spwd

sunau

telnetlib

uu

xdrlib

Other modules:

lib2to3, and the 2to3 program (gh-84540 [https://github.com/python/cpython/issues/84540])

APIs:

configparser.LegacyInterpolation (gh-90765 [https://github.com/python/cpython/issues/90765])

locale.resetlocale() (gh-90817 [https://github.com/python/cpython/issues/90817])

turtle.RawTurtle.settiltangle() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.findTestCases() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.getTestCaseNames() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.makeSuite() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.TestProgram.usageExit() (gh-67048 [https://github.com/python/cpython/issues/67048])

webbrowser.MacOSX (gh-86421 [https://github.com/python/cpython/issues/86421])

classmethod descriptor chaining (gh-89519 [https://github.com/python/cpython/issues/89519])

importlib.resources deprecated methods:

contents()

is_resource()

open_binary()

open_text()

path()

read_binary()

read_text()

Use importlib.resources.files() instead. Refer to importlib-resources: Migrating from Legacy [https://importlib-resources.readthedocs.io/en/latest/using.html#migrating-from-legacy] (gh-106531 [https://github.com/python/cpython/issues/106531])

Pending removal in Python 3.14

argparse: The type, choices, and metavar parameters of argparse.BooleanOptionalAction are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in gh-92248 [https://github.com/python/cpython/issues/92248].)

ast: The following features have been deprecated in documentation since Python 3.8, now cause a DeprecationWarning to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

ast.Num

ast.Str

ast.Bytes

ast.NameConstant

ast.Ellipsis

Use ast.Constant instead. (Contributed by Serhiy Storchaka in gh-90953 [https://github.com/python/cpython/issues/90953].)

asyncio:

The child watcher classes asyncio.MultiLoopChildWatcher, asyncio.FastChildWatcher, asyncio.AbstractChildWatcher and asyncio.SafeChildWatcher are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

asyncio.set_child_watcher(), asyncio.get_child_watcher(), asyncio.AbstractEventLoopPolicy.set_child_watcher() and asyncio.AbstractEventLoopPolicy.get_child_watcher() are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

The get_event_loop() method of the default event loop policy now emits a DeprecationWarning if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in gh-100160 [https://github.com/python/cpython/issues/100160].)

collections.abc: Deprecated collections.abc.ByteString. Prefer Sequence or Buffer. For use in typing, prefer a union, like bytes | bytearray, or collections.abc.Buffer. (Contributed by Shantanu Jain in gh-91896 [https://github.com/python/cpython/issues/91896].)

email: Deprecated the isdst parameter in email.utils.localtime(). (Contributed by Alan Williams in gh-72346 [https://github.com/python/cpython/issues/72346].)

importlib.abc deprecated classes:

importlib.abc.ResourceReader

importlib.abc.Traversable

importlib.abc.TraversableResources

Use importlib.resources.abc classes instead:

importlib.resources.abc.Traversable

importlib.resources.abc.TraversableResources

(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963 [https://github.com/python/cpython/issues/93963].)

itertools had undocumented, inefficient, historically buggy, and inconsistent support for copy, deepcopy, and pickle operations. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in gh-101588 [https://github.com/python/cpython/issues/101588].)

multiprocessing: The default start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where 'fork' is currently the default (gh-84559 [https://github.com/python/cpython/issues/84559]). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the get_context() or set_start_method() APIs to explicitly specify when your code requires 'fork'. See 컨텍스트 및 시작 방법.

pathlib: is_relative_to() and relative_to(): passing additional arguments is deprecated.

pkgutil: pkgutil.find_loader() and :func:!pkgutil.get_loader` now raise DeprecationWarning; use importlib.util.find_spec() instead. (Contributed by Nikita Sobolev in gh-97850 [https://github.com/python/cpython/issues/97850].)

pty:

master_open(): use pty.openpty().

slave_open(): use pty.openpty().

sqlite3:

version and version_info.

execute() and executemany() if named placeholders are used and parameters is a sequence instead of a dict.

typing: typing.ByteString, deprecated since Python 3.9, now causes a DeprecationWarning to be emitted when it is used.

urllib: urllib.parse.Quoter is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168 [https://github.com/python/cpython/issues/88168].)

Pending removal in Python 3.15

The import system:

Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

Setting __package__ on a module while failing to set __spec__.parent is deprecated. In Python 3.15, __package__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

ctypes:

The undocumented ctypes.SetPointerType() function has been deprecated since Python 3.13.

http.server:

The obsolete and rarely used CGIHTTPRequestHandler has been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.

The --cgi flag to the python -m http.server command-line interface has been deprecated since Python 3.13.

locale:

The getdefaultlocale() function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817 [https://github.com/python/cpython/issues/90817]), but has been postponed to Python 3.15. Use getlocale(), setlocale(), and getencoding() instead. (Contributed by Hugo van Kemenade in gh-111187 [https://github.com/python/cpython/issues/111187].)

pathlib:

PurePath.is_reserved() has been deprecated since Python 3.13. Use os.path.isreserved() to detect reserved paths on Windows.

platform:

java_ver() has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.

threading:

RLock() will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.

types:

types.CodeType: Accessing co_lnotab was deprecated in PEP 626 [https://peps.python.org/pep-0626/] since 3.10 and was planned to be removed in 3.12, but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

typing:

The undocumented keyword argument syntax for creating NamedTuple classes (for example, Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.

The typing.no_type_check_decorator() decorator function has been deprecated since Python 3.13. After eight years in the typing module, it has yet to be supported by any major type checker.

wave:

The getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes have been deprecated since Python 3.13.

Pending removal in Python 3.16

The import system:

Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

array:

The 'u' format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the 'w' format code (Py_UCS4) for Unicode characters instead.

asyncio:

asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins:

Bitwise inversion on boolean types, ~True or ~False has been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2 and -1). Use not x instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to int explicitly (~int(x)).

shutil:

The ExecError exception has been deprecated since Python 3.14. It has not been used by any function in shutil since Python 3.4, and is now an alias of RuntimeError.

symtable:

The Class.get_methods method has been deprecated since Python 3.14.

sys:

The _enablelegacywindowsfsencoding() function has been deprecated since Python 3.13. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead.

tarfile:

The undocumented and unused TarFile.tarfile attribute has been deprecated since Python 3.13.

Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

argparse:

Nesting argument groups and nesting mutually exclusive groups are deprecated.

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated.

The argparse.FileType type converter is deprecated.

array’s 'u' format code (gh-57281 [https://github.com/python/cpython/issues/57281])

builtins:

bool(NotImplemented).

Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In a future release it will be changed to a syntax error. (gh-87999 [https://github.com/python/cpython/issues/87999])

Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of int.

Support for __float__() method returning a strict subclass of float: these methods will be required to return an instance of float.

Support for __complex__() method returning a strict subclass of complex: these methods will be required to return an instance of complex.

Delegation of int() to __trunc__() method.

Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

codeobject.co_lnotab: use the codeobject.co_lines() method instead.

datetime:

utcnow(): use datetime.datetime.now(tz=datetime.UTC).

utcfromtimestamp(): use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).

gettext: Plural value must be an integer.

importlib:

load_module() method: use exec_module() instead.

cache_from_source() debug_override parameter is deprecated: use the optimization parameter instead.

importlib.metadata:

EntryPoints tuple interface.

Implicit None on return values.

logging: the warn() method has been deprecated since Python 3.3, use warning() instead.

mailbox: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

os: Calling os.register_at_fork() in multi-threaded process.

pydoc.ErrorDuringImport: A tuple value for exc_info parameter is deprecated, use an exception instance.

re: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

sre_compile, sre_constants and sre_parse modules.

shutil: rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

ssl options and protocols:

ssl.SSLContext without protocol argument is deprecated.

ssl.SSLContext: set_npn_protocols() and selected_npn_protocol() are deprecated: use ALPN instead.

ssl.OP_NO_SSL* options

ssl.OP_NO_TLS* options

ssl.PROTOCOL_SSLv3

ssl.PROTOCOL_TLS

ssl.PROTOCOL_TLSv1

ssl.PROTOCOL_TLSv1_1

ssl.PROTOCOL_TLSv1_2

ssl.TLSVersion.SSLv3

ssl.TLSVersion.TLSv1

ssl.TLSVersion.TLSv1_1

sysconfig.is_python_build() check_home parameter is deprecated and ignored.

threading methods:

threading.Condition.notifyAll(): use notify_all().

threading.Event.isSet(): use is_set().

threading.Thread.isDaemon(), threading.Thread.setDaemon(): use threading.Thread.daemon attribute.

threading.Thread.getName(), threading.Thread.setName(): use threading.Thread.name attribute.

threading.currentThread(): use threading.current_thread().

threading.activeCount(): use threading.active_count().

typing.Text (gh-92332 [https://github.com/python/cpython/issues/92332]).

unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.

urllib.parse deprecated functions: urlparse() instead

splitattr()

splithost()

splitnport()

splitpasswd()

splitport()

splitquery()

splittag()

splittype()

splituser()

splitvalue()

to_bytes()

wsgiref: SimpleHandler.stdout.write() should not do partial writes.

xml.etree.ElementTree: Testing the truth value of an Element is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.

zipimport.zipimporter.load_module() is deprecated: use exec_module() instead.

Removed

asynchat and asyncore

These two modules have been removed according to the schedule in PEP 594 [https://peps.python.org/pep-0594/], having been deprecated in Python 3.6. Use asyncio instead. (Contributed by Nikita Sobolev in gh-96580 [https://github.com/python/cpython/issues/96580].)

configparser

Several names deprecated in the configparser way back in 3.2 have been removed per gh-89336 [https://github.com/python/cpython/issues/89336]:

configparser.ParsingError no longer has a filename attribute or argument. Use the source attribute and argument instead.

configparser no longer has a SafeConfigParser class. Use the shorter ConfigParser name instead.

configparser.ConfigParser no longer has a readfp method. Use read_file() instead.

distutils

Remove the distutils package. It was deprecated in Python 3.10 by PEP 632 [https://peps.python.org/pep-0632/] “Deprecate distutils module”. For projects still using distutils and cannot be updated to something else, the setuptools project can be installed: it still provides distutils. (Contributed by Victor Stinner in gh-92584 [https://github.com/python/cpython/issues/92584].)

ensurepip

Remove the bundled setuptools wheel from ensurepip, and stop installing setuptools in environments created by venv.

pip (>= 22.1) does not require setuptools to be installed in the environment. setuptools-based (and distutils-based) packages can still be used with pip install, since pip will provide setuptools in the build environment it uses for building a package.

easy_install, pkg_resources, setuptools and distutils are no longer provided by default in environments created with venv or bootstrapped with ensurepip, since they are part of the setuptools package. For projects relying on these at runtime, the setuptools project should be declared as a dependency and installed separately (typically, using pip).

(Contributed by Pradyun Gedam in gh-95299 [https://github.com/python/cpython/issues/95299].)

enum

Remove enum’s EnumMeta.__getattr__, which is no longer needed for enum attribute access. (Contributed by Ethan Furman in gh-95083 [https://github.com/python/cpython/issues/95083].)

ftplib

Remove ftplib’s FTP_TLS.ssl_version class attribute: use the context parameter instead. (Contributed by Victor Stinner in gh-94172 [https://github.com/python/cpython/issues/94172].)

gzip

Remove the filename attribute of gzip’s gzip.GzipFile, deprecated since Python 2.6, use the name attribute instead. In write mode, the filename attribute added '.gz' file extension if it was not present. (Contributed by Victor Stinner in gh-94196 [https://github.com/python/cpython/issues/94196].)

hashlib

Remove the pure Python implementation of hashlib’s hashlib.pbkdf2_hmac(), deprecated in Python 3.10. Python 3.10 and newer requires OpenSSL 1.1.1 (PEP 644 [https://peps.python.org/pep-0644/]): this OpenSSL version provides a C implementation of pbkdf2_hmac() which is faster. (Contributed by Victor Stinner in gh-94199 [https://github.com/python/cpython/issues/94199].)

importlib

Many previously deprecated cleanups in importlib have now been completed:

References to, and support for module_repr() has been removed. (Contributed by Barry Warsaw in gh-97850 [https://github.com/python/cpython/issues/97850].)

importlib.util.set_package, importlib.util.set_loader and importlib.util.module_for_loader have all been removed. (Contributed by Brett Cannon and Nikita Sobolev in gh-65961 [https://github.com/python/cpython/issues/65961] and gh-97850 [https://github.com/python/cpython/issues/97850].)

Support for find_loader() and find_module() APIs have been removed. (Contributed by Barry Warsaw in gh-98040 [https://github.com/python/cpython/issues/98040].)

importlib.abc.Finder, pkgutil.ImpImporter, and pkgutil.ImpLoader have been removed. (Contributed by Barry Warsaw in gh-98040 [https://github.com/python/cpython/issues/98040].)

imp

The imp module has been removed. (Contributed by Barry Warsaw in gh-98040 [https://github.com/python/cpython/issues/98040].)

To migrate, consult the following correspondence table:

imp

importlib

imp.NullImporter

Insert None into sys.path_importer_cache

imp.cache_from_source()

importlib.util.cache_from_source()

imp.find_module()

importlib.util.find_spec()

imp.get_magic()

importlib.util.MAGIC_NUMBER

imp.get_suffixes()

importlib.machinery.SOURCE_SUFFIXES, importlib.machinery.EXTENSION_SUFFIXES, and importlib.machinery.BYTECODE_SUFFIXES

imp.get_tag()

sys.implementation.cache_tag

imp.load_module()

importlib.import_module()

imp.new_module(name)

types.ModuleType(name)

imp.reload()

importlib.reload()

imp.source_from_cache()

importlib.util.source_from_cache()

imp.load_source()

See below

Replace imp.load_source() with:

import importlib.util
import importlib.machinery

def load_source(modname, filename):
    loader = importlib.machinery.SourceFileLoader(modname, filename)
    spec = importlib.util.spec_from_file_location(modname, filename, loader=loader)
    module = importlib.util.module_from_spec(spec)
    # The module is always executed and not cached in sys.modules.
    # Uncomment the following line to cache the module.
    # sys.modules[module.__name__] = module
    loader.exec_module(module)
    return module

Remove imp functions and attributes with no replacements:

Undocumented functions:

imp.init_builtin()

imp.load_compiled()

imp.load_dynamic()

imp.load_package()

imp.lock_held(), imp.acquire_lock(), imp.release_lock(): the locking scheme has changed in Python 3.3 to per-module locks.

imp.find_module() constants: SEARCH_ERROR, PY_SOURCE, PY_COMPILED, C_EXTENSION, PY_RESOURCE, PKG_DIRECTORY, C_BUILTIN, PY_FROZEN, PY_CODERESOURCE, IMP_HOOK.

io

Remove io’s io.OpenWrapper and _pyio.OpenWrapper, deprecated in Python 3.10: just use open() instead. The open() (io.open()) function is a built-in function. Since Python 3.10, _pyio.open() is also a static method. (Contributed by Victor Stinner in gh-94169 [https://github.com/python/cpython/issues/94169].)

locale

Remove locale’s locale.format() function, deprecated in Python 3.7: use locale.format_string() instead. (Contributed by Victor Stinner in gh-94226 [https://github.com/python/cpython/issues/94226].)

smtpd

The smtpd module has been removed according to the schedule in PEP 594 [https://peps.python.org/pep-0594/], having been deprecated in Python 3.4.7 and 3.5.4. Use the aiosmtpd [https://pypi.org/project/aiosmtpd/] PyPI module or any other asyncio-based server instead. (Contributed by Oleg Iarygin in gh-93243 [https://github.com/python/cpython/issues/93243].)

sqlite3

The following undocumented sqlite3 features, deprecated in Python 3.10, are now removed:

sqlite3.enable_shared_cache()

sqlite3.OptimizedUnicode

If a shared cache must be used, open the database in URI mode using the cache=shared query parameter.

The sqlite3.OptimizedUnicode text factory has been an alias for str since Python 3.3. Code that previously set the text factory to OptimizedUnicode can either use str explicitly, or rely on the default value which is also str.

(Contributed by Erlend E. Aasland in gh-92548 [https://github.com/python/cpython/issues/92548].)

ssl

Remove ssl’s ssl.RAND_pseudo_bytes() function, deprecated in Python 3.6: use os.urandom() or ssl.RAND_bytes() instead. (Contributed by Victor Stinner in gh-94199 [https://github.com/python/cpython/issues/94199].)

Remove the ssl.match_hostname() function. It was deprecated in Python 3.7. OpenSSL performs hostname matching since Python 3.7, Python no longer uses the ssl.match_hostname() function. (Contributed by Victor Stinner in gh-94199 [https://github.com/python/cpython/issues/94199].)

Remove the ssl.wrap_socket() function, deprecated in Python 3.7: instead, create a ssl.SSLContext object and call its ssl.SSLContext.wrap_socket method. Any package that still uses ssl.wrap_socket() is broken and insecure. The function neither sends a SNI TLS extension nor validates the server hostname. Code is subject to CWE 295 [https://cwe.mitre.org/data/definitions/295.html] (Improper Certificate Validation). (Contributed by Victor Stinner in gh-94199 [https://github.com/python/cpython/issues/94199].)

unittest

Remove many long-deprecated unittest features:

A number of TestCase method aliases:

Deprecated alias

Method Name

Deprecated in

failUnless

assertTrue()

3.1

failIf

assertFalse()

3.1

failUnlessEqual

assertEqual()

3.1

failIfEqual

assertNotEqual()

3.1

failUnlessAlmostEqual

assertAlmostEqual()

3.1

failIfAlmostEqual

assertNotAlmostEqual()

3.1

failUnlessRaises

assertRaises()

3.1

assert_

assertTrue()

3.2

assertEquals

assertEqual()

3.2

assertNotEquals

assertNotEqual()

3.2

assertAlmostEquals

assertAlmostEqual()

3.2

assertNotAlmostEquals

assertNotAlmostEqual()

3.2

assertRegexpMatches

assertRegex()

3.2

assertRaisesRegexp

assertRaisesRegex()

3.2

assertNotRegexpMatches

assertNotRegex()

3.5

You can use https://github.com/isidentical/teyit to automatically modernise your unit tests.

Undocumented and broken TestCase method assertDictContainsSubset (deprecated in Python 3.2).

Undocumented TestLoader.loadTestsFromModule parameter use_load_tests (deprecated and ignored since Python 3.5).

An alias of the TextTestResult class: _TextTestResult (deprecated in Python 3.2).

(Contributed by Serhiy Storchaka in gh-89325 [https://github.com/python/cpython/issues/89325].)

webbrowser

Remove support for obsolete browsers from webbrowser. The removed browsers include: Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below (gh-102871 [https://github.com/python/cpython/issues/102871]).

xml.etree.ElementTree

Remove the ElementTree.Element.copy() method of the pure Python implementation, deprecated in Python 3.10, use the copy.copy() function instead. The C implementation of xml.etree.ElementTree has no copy() method, only a __copy__() method. (Contributed by Victor Stinner in gh-94383 [https://github.com/python/cpython/issues/94383].)

zipimport

Remove zipimport’s find_loader() and find_module() methods, deprecated in Python 3.10: use the find_spec() method instead. See PEP 451 [https://peps.python.org/pep-0451/] for the rationale. (Contributed by Victor Stinner in gh-94379 [https://github.com/python/cpython/issues/94379].)

Others

Remove the suspicious rule from the documentation Makefile and Doc/tools/rstlint.py, both in favor of sphinx-lint [https://github.com/sphinx-contrib/sphinx-lint]. (Contributed by Julien Palard in gh-98179 [https://github.com/python/cpython/issues/98179].)

Remove the keyfile and certfile parameters from the ftplib, imaplib, poplib and smtplib modules, and the key_file, cert_file and check_hostname parameters from the http.client module, all deprecated since Python 3.6. Use the context parameter (ssl_context in imaplib) instead. (Contributed by Victor Stinner in gh-94172 [https://github.com/python/cpython/issues/94172].)

Remove Jython compatibility hacks from several stdlib modules and tests. (Contributed by Nikita Sobolev in gh-99482 [https://github.com/python/cpython/issues/99482].)

Remove _use_broken_old_ctypes_structure_semantics_ flag from ctypes module. (Contributed by Nikita Sobolev in gh-99285 [https://github.com/python/cpython/issues/99285].)

Porting to Python 3.12

This section lists previously described changes and other bugfixes that may require changes to your code.

Changes in the Python API

More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

Remove randrange() functionality deprecated since Python 3.10. Formerly, randrange(10.0) losslessly converted to randrange(10). Now, it raises a TypeError. Also, the exception raised for non-integer values such as randrange(10.5) or randrange('10') has been changed from ValueError to TypeError. This also prevents bugs where randrange(1e25) would silently select from a larger range than randrange(10**25). (Originally suggested by Serhiy Storchaka gh-86388 [https://github.com/python/cpython/issues/86388].)

argparse.ArgumentParser changed encoding and error handler for reading arguments from file (e.g. fromfile_prefix_chars option) from default text encoding (e.g. locale.getpreferredencoding(False)) to filesystem encoding and error handler. Argument files should be encoded in UTF-8 instead of ANSI Codepage on Windows.

Remove the asyncore-based smtpd module deprecated in Python 3.4.7 and 3.5.4. A recommended replacement is the asyncio-based aiosmtpd [https://pypi.org/project/aiosmtpd/] PyPI module.

shlex.split(): Passing None for s argument now raises an exception, rather than reading sys.stdin. The feature was deprecated in Python 3.9. (Contributed by Victor Stinner in gh-94352 [https://github.com/python/cpython/issues/94352].)

The os module no longer accepts bytes-like paths, like bytearray and memoryview types: only the exact bytes type is accepted for bytes strings. (Contributed by Victor Stinner in gh-98393 [https://github.com/python/cpython/issues/98393].)

syslog.openlog() and syslog.closelog() now fail if used in subinterpreters. syslog.syslog() may still be used in subinterpreters, but now only if syslog.openlog() has already been called in the main interpreter. These new restrictions do not apply to the main interpreter, so only a very small set of users might be affected. This change helps with interpreter isolation. Furthermore, syslog is a wrapper around process-global resources, which are best managed from the main interpreter. (Contributed by Donghee Na in gh-99127 [https://github.com/python/cpython/issues/99127].)

The undocumented locking behavior of cached_property() is removed, because it locked across all instances of the class, leading to high lock contention. This means that a cached property getter function could now run more than once for a single instance, if two threads race. For most simple cached properties (e.g. those that are idempotent and simply calculate a value based on other attributes of the instance) this will be fine. If synchronization is needed, implement locking within the cached property getter function or around multi-threaded access points.

sys._current_exceptions() now returns a mapping from thread-id to an exception instance, rather than to a (typ, exc, tb) tuple. (Contributed by Irit Katriel in gh-103176 [https://github.com/python/cpython/issues/103176].)

When extracting tar files using tarfile or shutil.unpack_archive(), pass the filter argument to limit features that may be surprising or dangerous. See Extraction filters for details.

The output of the tokenize.tokenize() and tokenize.generate_tokens() functions is now changed due to the changes introduced in PEP 701 [https://peps.python.org/pep-0701/]. This means that STRING tokens are not emitted any more for f-strings and the tokens described in PEP 701 [https://peps.python.org/pep-0701/] are now produced instead: FSTRING_START, FSTRING_MIDDLE and FSTRING_END are now emitted for f-string “string” parts in addition to the appropriate tokens for the tokenization in the expression components. For example for the f-string f"start {1+1} end" the old version of the tokenizer emitted:

1,0-1,18:           STRING         'f"start {1+1} end"'

while the new version emits:

1,0-1,2:            FSTRING_START  'f"'
1,2-1,8:            FSTRING_MIDDLE 'start '
1,8-1,9:            OP             '{'
1,9-1,10:           NUMBER         '1'
1,10-1,11:          OP             '+'
1,11-1,12:          NUMBER         '1'
1,12-1,13:          OP             '}'
1,13-1,17:          FSTRING_MIDDLE ' end'
1,17-1,18:          FSTRING_END    '"'

Additionally, there may be some minor behavioral changes as a consequence of the changes required to support PEP 701 [https://peps.python.org/pep-0701/]. Some of these changes include:

The type attribute of the tokens emitted when tokenizing some invalid Python characters such as ! has changed from ERRORTOKEN to OP.

Incomplete single-line strings now also raise tokenize.TokenError as incomplete multiline strings do.

Some incomplete or invalid Python code now raises tokenize.TokenError instead of returning arbitrary ERRORTOKEN tokens when tokenizing it.

Mixing tabs and spaces as indentation in the same file is not supported anymore and will raise a TabError.

The threading module now expects the _thread module to have an _is_main_interpreter attribute. It is a function with no arguments that returns True if the current interpreter is the main interpreter.

Any library or application that provides a custom _thread module should provide _is_main_interpreter(). (See gh-112826 [https://github.com/python/cpython/issues/112826].)

Build Changes

Python no longer uses setup.py to build shared C extension modules. Build parameters like headers and libraries are detected in configure script. Extensions are built by Makefile. Most extensions use pkg-config and fall back to manual detection. (Contributed by Christian Heimes in gh-93939 [https://github.com/python/cpython/issues/93939].)

va_start() with two parameters, like va_start(args, format), is now required to build Python. va_start() is no longer called with a single parameter. (Contributed by Kumar Aditya in gh-93207 [https://github.com/python/cpython/issues/93207].)

CPython now uses the ThinLTO option as the default link time optimization policy if the Clang compiler accepts the flag. (Contributed by Donghee Na in gh-89536 [https://github.com/python/cpython/issues/89536].)

Add COMPILEALL_OPTS variable in Makefile to override compileall options (default: -j0) in make install. Also merged the 3 compileall commands into a single command to build .pyc files for all optimization levels (0, 1, 2) at once. (Contributed by Victor Stinner in gh-99289 [https://github.com/python/cpython/issues/99289].)

Add platform triplets for 64-bit LoongArch:

loongarch64-linux-gnusf

loongarch64-linux-gnuf32

loongarch64-linux-gnu

(Contributed by Zhang Na in gh-90656 [https://github.com/python/cpython/issues/90656].)

PYTHON_FOR_REGEN now require Python 3.10 or newer.

Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate !configure. (Contributed by Christian Heimes in gh-89886 [https://github.com/python/cpython/issues/89886].)

Windows builds and macOS installers from python.org now use OpenSSL 3.0.

C API Changes

New Features

PEP 697 [https://peps.python.org/pep-0697/]: Introduce the Unstable C API tier, intended for low-level tools like debuggers and JIT compilers. This API may change in each minor release of CPython without deprecation warnings. Its contents are marked by the PyUnstable_ prefix in names.

Code object constructors:

PyUnstable_Code_New() (renamed from PyCode_New)

PyUnstable_Code_NewWithPosOnlyArgs() (renamed from PyCode_NewWithPosOnlyArgs)

Extra storage for code objects (PEP 523 [https://peps.python.org/pep-0523/]):

PyUnstable_Eval_RequestCodeExtraIndex() (renamed from _PyEval_RequestCodeExtraIndex)

PyUnstable_Code_GetExtra() (renamed from _PyCode_GetExtra)

PyUnstable_Code_SetExtra() (renamed from _PyCode_SetExtra)

The original names will continue to be available until the respective API changes.

(Contributed by Petr Viktorin in gh-101101 [https://github.com/python/cpython/issues/101101].)

PEP 697 [https://peps.python.org/pep-0697/]: Add an API for extending types whose instance memory layout is opaque:

PyType_Spec.basicsize can be zero or negative to specify inheriting or extending the base class size.

PyObject_GetTypeData() and PyType_GetTypeDataSize() added to allow access to subclass-specific instance data.

Py_TPFLAGS_ITEMS_AT_END and PyObject_GetItemData() added to allow safely extending certain variable-sized types, including PyType_Type.

Py_RELATIVE_OFFSET added to allow defining members in terms of a subclass-specific struct.

(Contributed by Petr Viktorin in gh-103509 [https://github.com/python/cpython/issues/103509].)

Add the new limited C API function PyType_FromMetaclass(), which generalizes the existing PyType_FromModuleAndSpec() using an additional metaclass argument. (Contributed by Wenzel Jakob in gh-93012 [https://github.com/python/cpython/issues/93012].)

API for creating objects that can be called using the vectorcall protocol was added to the Limited API:

Py_TPFLAGS_HAVE_VECTORCALL

PyVectorcall_NARGS()

PyVectorcall_Call()

vectorcallfunc

The Py_TPFLAGS_HAVE_VECTORCALL flag is now removed from a class when the class’s __call__() method is reassigned. This makes vectorcall safe to use with mutable types (i.e. heap types without the immutable flag, Py_TPFLAGS_IMMUTABLETYPE). Mutable types that do not override tp_call now inherit the Py_TPFLAGS_HAVE_VECTORCALL flag. (Contributed by Petr Viktorin in gh-93274 [https://github.com/python/cpython/issues/93274].)

The Py_TPFLAGS_MANAGED_DICT and Py_TPFLAGS_MANAGED_WEAKREF flags have been added. This allows extensions classes to support object __dict__ and weakrefs with less bookkeeping, using less memory and with faster access.

API for performing calls using the vectorcall protocol was added to the Limited API:

PyObject_Vectorcall()

PyObject_VectorcallMethod()

PY_VECTORCALL_ARGUMENTS_OFFSET

This means that both the incoming and outgoing ends of the vector call protocol are now available in the Limited API. (Contributed by Wenzel Jakob in gh-98586 [https://github.com/python/cpython/issues/98586].)

Add two new public functions, PyEval_SetProfileAllThreads() and PyEval_SetTraceAllThreads(), that allow to set tracing and profiling functions in all running threads in addition to the calling one. (Contributed by Pablo Galindo in gh-93503 [https://github.com/python/cpython/issues/93503].)

Add new function PyFunction_SetVectorcall() to the C API which sets the vectorcall field of a given PyFunctionObject. (Contributed by Andrew Frost in gh-92257 [https://github.com/python/cpython/issues/92257].)

The C API now permits registering callbacks via PyDict_AddWatcher(), PyDict_Watch() and related APIs to be called whenever a dictionary is modified. This is intended for use by optimizing interpreters, JIT compilers, or debuggers. (Contributed by Carl Meyer in gh-91052 [https://github.com/python/cpython/issues/91052].)

Add PyType_AddWatcher() and PyType_Watch() API to register callbacks to receive notification on changes to a type. (Contributed by Carl Meyer in gh-91051 [https://github.com/python/cpython/issues/91051].)

Add PyCode_AddWatcher() and PyCode_ClearWatcher() APIs to register callbacks to receive notification on creation and destruction of code objects. (Contributed by Itamar Oren in gh-91054 [https://github.com/python/cpython/issues/91054].)

Add PyFrame_GetVar() and PyFrame_GetVarString() functions to get a frame variable by its name. (Contributed by Victor Stinner in gh-91248 [https://github.com/python/cpython/issues/91248].)

Add PyErr_GetRaisedException() and PyErr_SetRaisedException() for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecated PyErr_Fetch() and PyErr_Restore(). This is less error prone and a bit more efficient. (Contributed by Mark Shannon in gh-101578 [https://github.com/python/cpython/issues/101578].)

Add _PyErr_ChainExceptions1, which takes an exception instance, to replace the legacy-API _PyErr_ChainExceptions, which is now deprecated. (Contributed by Mark Shannon in gh-101578 [https://github.com/python/cpython/issues/101578].)

Add PyException_GetArgs() and PyException_SetArgs() as convenience functions for retrieving and modifying the args passed to the exception’s constructor. (Contributed by Mark Shannon in gh-101578 [https://github.com/python/cpython/issues/101578].)

Add PyErr_DisplayException(), which takes an exception instance, to replace the legacy-api PyErr_Display(). (Contributed by Irit Katriel in gh-102755 [https://github.com/python/cpython/issues/102755]).

PEP 683 [https://peps.python.org/pep-0683/]: Introduce Immortal Objects, which allows objects to bypass reference counts, and related changes to the C-API:

_Py_IMMORTAL_REFCNT: The reference count that defines an object

as immortal.

_Py_IsImmortal Checks if an object has the immortal reference count.

PyObject_HEAD_INIT This will now initialize reference count to

_Py_IMMORTAL_REFCNT when used with Py_BUILD_CORE.

SSTATE_INTERNED_IMMORTAL An identifier for interned unicode objects

that are immortal.

SSTATE_INTERNED_IMMORTAL_STATIC An identifier for interned unicode

objects that are immortal and static

sys.getunicodeinternedsize This returns the total number of unicode

objects that have been interned. This is now needed for refleak.py to correctly track reference counts and allocated blocks

(Contributed by Eddie Elizondo in gh-84436 [https://github.com/python/cpython/issues/84436].)

PEP 684 [https://peps.python.org/pep-0684/]: Add the new Py_NewInterpreterFromConfig() function and PyInterpreterConfig, which may be used to create sub-interpreters with their own GILs. (See PEP 684: A Per-Interpreter GIL for more info.) (Contributed by Eric Snow in gh-104110 [https://github.com/python/cpython/issues/104110].)

In the limited C API version 3.12, Py_INCREF() and Py_DECREF() functions are now implemented as opaque function calls to hide implementation details. (Contributed by Victor Stinner in gh-105387 [https://github.com/python/cpython/issues/105387].)

Porting to Python 3.12

Legacy Unicode APIs based on Py_UNICODE* representation has been removed. Please migrate to APIs based on UTF-8 or wchar_t*.

Argument parsing functions like PyArg_ParseTuple() doesn’t support Py_UNICODE* based format (e.g. u, Z) anymore. Please migrate to other formats for Unicode like s, z, es, and U.

tp_weaklist for all static builtin types is always NULL. This is an internal-only field on PyTypeObject but we’re pointing out the change in case someone happens to be accessing the field directly anyway. To avoid breakage, consider using the existing public C-API instead, or, if necessary, the (internal-only) _PyObject_GET_WEAKREFS_LISTPTR() macro.

This internal-only PyTypeObject.tp_subclasses may now not be a valid object pointer. Its type was changed to void* to reflect this. We mention this in case someone happens to be accessing the internal-only field directly.

To get a list of subclasses, call the Python method __subclasses__() (using PyObject_CallMethod(), for example).

Add support of more formatting options (left aligning, octals, uppercase hexadecimals, intmax_t, ptrdiff_t, wchar_t C strings, variable width and precision) in PyUnicode_FromFormat() and PyUnicode_FromFormatV(). (Contributed by Serhiy Storchaka in gh-98836 [https://github.com/python/cpython/issues/98836].)

An unrecognized format character in PyUnicode_FromFormat() and PyUnicode_FromFormatV() now sets a SystemError. In previous versions it caused all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded. (Contributed by Serhiy Storchaka in gh-95781 [https://github.com/python/cpython/issues/95781].)

Fix wrong sign placement in PyUnicode_FromFormat() and PyUnicode_FromFormatV(). (Contributed by Philip Georgi in gh-95504 [https://github.com/python/cpython/issues/95504].)

Extension classes wanting to add a __dict__ or weak reference slot should use Py_TPFLAGS_MANAGED_DICT and Py_TPFLAGS_MANAGED_WEAKREF instead of tp_dictoffset and tp_weaklistoffset, respectively. The use of tp_dictoffset and tp_weaklistoffset is still supported, but does not fully support multiple inheritance (gh-95589 [https://github.com/python/cpython/issues/95589]), and performance may be worse. Classes declaring Py_TPFLAGS_MANAGED_DICT must call _PyObject_VisitManagedDict() and _PyObject_ClearManagedDict() to traverse and clear their instance’s dictionaries. To clear weakrefs, call PyObject_ClearWeakRefs(), as before.

The PyUnicode_FSDecoder() function no longer accepts bytes-like paths, like bytearray and memoryview types: only the exact bytes type is accepted for bytes strings. (Contributed by Victor Stinner in gh-98393 [https://github.com/python/cpython/issues/98393].)

The Py_CLEAR, Py_SETREF and Py_XSETREF macros now only evaluate their arguments once. If an argument has side effects, these side effects are no longer duplicated. (Contributed by Victor Stinner in gh-98724 [https://github.com/python/cpython/issues/98724].)

The interpreter’s error indicator is now always normalized. This means that PyErr_SetObject(), PyErr_SetString() and the other functions that set the error indicator now normalize the exception before storing it. (Contributed by Mark Shannon in gh-101578 [https://github.com/python/cpython/issues/101578].)

_Py_RefTotal is no longer authoritative and only kept around for ABI compatibility. Note that it is an internal global and only available on debug builds. If you happen to be using it then you’ll need to start using _Py_GetGlobalRefTotal().

The following functions now select an appropriate metaclass for the newly created type:

PyType_FromSpec()

PyType_FromSpecWithBases()

PyType_FromModuleAndSpec()

Creating classes whose metaclass overrides tp_new is deprecated, and in Python 3.14+ it will be disallowed. Note that these functions ignore tp_new of the metaclass, possibly allowing incomplete initialization.

Note that PyType_FromMetaclass() (added in Python 3.12) already disallows creating classes whose metaclass overrides tp_new (__new__() in Python).

Since tp_new overrides almost everything PyType_From* functions do, the two are incompatible with each other. The existing behavior – ignoring the metaclass for several steps of type creation – is unsafe in general, since (meta)classes assume that tp_new was called. There is no simple general workaround. One of the following may work for you:

If you control the metaclass, avoid using tp_new in it:

If initialization can be skipped, it can be done in tp_init instead.

If the metaclass doesn’t need to be instantiated from Python, set its tp_new to NULL using the Py_TPFLAGS_DISALLOW_INSTANTIATION flag. This makes it acceptable for PyType_From* functions.

Avoid PyType_From* functions: if you don’t need C-specific features (slots or setting the instance size), create types by calling the metaclass.

If you know the tp_new can be skipped safely, filter the deprecation warning out using warnings.catch_warnings() from Python.

PyOS_InputHook and PyOS_ReadlineFunctionPointer are no longer called in subinterpreters. This is because clients generally rely on process-wide global state (since these callbacks have no way of recovering extension module state).

This also avoids situations where extensions may find themselves running in a subinterpreter that they don’t support (or haven’t yet been loaded in). See gh-104668 [https://github.com/python/cpython/issues/104668] for more info.

PyLongObject has had its internals changed for better performance. Although the internals of PyLongObject are private, they are used by some extension modules. The internal fields should no longer be accessed directly, instead the API functions beginning PyLong_... should be used instead. Two new unstable API functions are provided for efficient access to the value of PyLongObjects which fit into a single machine word:

PyUnstable_Long_IsCompact()

PyUnstable_Long_CompactValue()

Custom allocators, set via PyMem_SetAllocator(), are now required to be thread-safe, regardless of memory domain. Allocators that don’t have their own state, including “hooks”, are not affected. If your custom allocator is not already thread-safe and you need guidance then please create a new GitHub issue and CC @ericsnowcurrently.

Deprecated

In accordance with PEP 699 [https://peps.python.org/pep-0699/], the ma_version_tag field in PyDictObject is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14. (Contributed by Ramvikrams and Kumar Aditya in gh-101193 [https://github.com/python/cpython/issues/101193]. PEP by Ken Jin.)

Deprecate global configuration variable:

Py_DebugFlag: use PyConfig.parser_debug

Py_VerboseFlag: use PyConfig.verbose

Py_QuietFlag: use PyConfig.quiet

Py_InteractiveFlag: use PyConfig.interactive

Py_InspectFlag: use PyConfig.inspect

Py_OptimizeFlag: use PyConfig.optimization_level

Py_NoSiteFlag: use PyConfig.site_import

Py_BytesWarningFlag: use PyConfig.bytes_warning

Py_FrozenFlag: use PyConfig.pathconfig_warnings

Py_IgnoreEnvironmentFlag: use PyConfig.use_environment

Py_DontWriteBytecodeFlag: use PyConfig.write_bytecode

Py_NoUserSiteDirectory: use PyConfig.user_site_directory

Py_UnbufferedStdioFlag: use PyConfig.buffered_stdio

Py_HashRandomizationFlag: use PyConfig.use_hash_seed and PyConfig.hash_seed

Py_IsolatedFlag: use PyConfig.isolated

Py_LegacyWindowsFSEncodingFlag: use PyPreConfig.legacy_windows_fs_encoding

Py_LegacyWindowsStdioFlag: use PyConfig.legacy_windows_stdio

Py_FileSystemDefaultEncoding: use PyConfig.filesystem_encoding

Py_HasFileSystemDefaultEncoding: use PyConfig.filesystem_encoding

Py_FileSystemDefaultEncodeErrors: use PyConfig.filesystem_errors

Py_UTF8Mode: use PyPreConfig.utf8_mode (see Py_PreInitialize())

The Py_InitializeFromConfig() API should be used with PyConfig instead. (Contributed by Victor Stinner in gh-77782 [https://github.com/python/cpython/issues/77782].)

Creating immutable types with mutable bases is deprecated and will be disabled in Python 3.14. (gh-95388 [https://github.com/python/cpython/issues/95388])

The structmember.h header is deprecated, though it continues to be available and there are no plans to remove it.

Its contents are now available just by including Python.h, with a Py prefix added if it was missing:

PyMemberDef, PyMember_GetOne() and PyMember_SetOne()

Type macros like Py_T_INT, Py_T_DOUBLE, etc. (previously T_INT, T_DOUBLE, etc.)

The flags Py_READONLY (previously READONLY) and Py_AUDIT_READ (previously all uppercase)

Several items are not exposed from Python.h:

T_OBJECT (use Py_T_OBJECT_EX)

T_NONE (previously undocumented, and pretty quirky)

The macro WRITE_RESTRICTED which does nothing.

The macros RESTRICTED and READ_RESTRICTED, equivalents of Py_AUDIT_READ.

In some configurations, <stddef.h> is not included from Python.h. It should be included manually when using offsetof().

The deprecated header continues to provide its original contents under the original names. Your old code can stay unchanged, unless the extra include and non-namespaced macros bother you greatly.

(Contributed in gh-47146 [https://github.com/python/cpython/issues/47146] by Petr Viktorin, based on earlier work by Alexander Belopolsky and Matthias Braun.)

PyErr_Fetch() and PyErr_Restore() are deprecated. Use PyErr_GetRaisedException() and PyErr_SetRaisedException() instead. (Contributed by Mark Shannon in gh-101578 [https://github.com/python/cpython/issues/101578].)

PyErr_Display() is deprecated. Use PyErr_DisplayException() instead. (Contributed by Irit Katriel in gh-102755 [https://github.com/python/cpython/issues/102755]).

_PyErr_ChainExceptions is deprecated. Use _PyErr_ChainExceptions1 instead. (Contributed by Irit Katriel in gh-102192 [https://github.com/python/cpython/issues/102192].)

Using PyType_FromSpec(), PyType_FromSpecWithBases() or PyType_FromModuleAndSpec() to create a class whose metaclass overrides tp_new is deprecated. Call the metaclass instead.

Pending removal in Python 3.14

The ma_version_tag field in PyDictObject for extension modules (PEP 699 [https://peps.python.org/pep-0699/]; gh-101193 [https://github.com/python/cpython/issues/101193]).

Creating immutable types with mutable bases (gh-95388 [https://github.com/python/cpython/issues/95388]).

Functions to configure Python’s initialization, deprecated in Python 3.11:

PySys_SetArgvEx(): Set PyConfig.argv instead.

PySys_SetArgv(): Set PyConfig.argv instead.

Py_SetProgramName(): Set PyConfig.program_name instead.

Py_SetPythonHome(): Set PyConfig.home instead.

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Global configuration variables:

Py_DebugFlag: Use PyConfig.parser_debug instead.

Py_VerboseFlag: Use PyConfig.verbose instead.

Py_QuietFlag: Use PyConfig.quiet instead.

Py_InteractiveFlag: Use PyConfig.interactive instead.

Py_InspectFlag: Use PyConfig.inspect instead.

Py_OptimizeFlag: Use PyConfig.optimization_level instead.

Py_NoSiteFlag: Use PyConfig.site_import instead.

Py_BytesWarningFlag: Use PyConfig.bytes_warning instead.

Py_FrozenFlag: Use PyConfig.pathconfig_warnings instead.

Py_IgnoreEnvironmentFlag: Use PyConfig.use_environment instead.

Py_DontWriteBytecodeFlag: Use PyConfig.write_bytecode instead.

Py_NoUserSiteDirectory: Use PyConfig.user_site_directory instead.

Py_UnbufferedStdioFlag: Use PyConfig.buffered_stdio instead.

Py_HashRandomizationFlag: Use PyConfig.use_hash_seed and PyConfig.hash_seed instead.

Py_IsolatedFlag: Use PyConfig.isolated instead.

Py_LegacyWindowsFSEncodingFlag: Use PyPreConfig.legacy_windows_fs_encoding instead.

Py_LegacyWindowsStdioFlag: Use PyConfig.legacy_windows_stdio instead.

Py_FileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_HasFileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_FileSystemDefaultEncodeErrors: Use PyConfig.filesystem_errors instead.

Py_UTF8Mode: Use PyPreConfig.utf8_mode instead. (see Py_PreInitialize())

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Pending removal in Python 3.15

The bundled copy of libmpdecimal.

The PyImport_ImportModuleNoBlock(): Use PyImport_ImportModule() instead.

PyWeakref_GetObject() and PyWeakref_GET_OBJECT(): Use PyWeakref_GetRef() instead.

Py_UNICODE type and the Py_UNICODE_WIDE macro: Use wchar_t instead.

Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.base_exec_prefix and sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.base_prefix and sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

Py_TPFLAGS_HAVE_FINALIZE: Unneeded since Python 3.8.

PyErr_Fetch(): Use PyErr_GetRaisedException() instead.

PyErr_NormalizeException(): Use PyErr_GetRaisedException() instead.

PyErr_Restore(): Use PyErr_SetRaisedException() instead.

PyModule_GetFilename(): Use PyModule_GetFilenameObject() instead.

PyOS_AfterFork(): Use PyOS_AfterFork_Child() instead.

PySlice_GetIndicesEx(): Use PySlice_Unpack() and PySlice_AdjustIndices() instead.

PyUnicode_AsDecodedObject(): Use PyCodec_Decode() instead.

PyUnicode_AsDecodedUnicode(): Use PyCodec_Decode() instead.

PyUnicode_AsEncodedObject(): Use PyCodec_Encode() instead.

PyUnicode_AsEncodedUnicode(): Use PyCodec_Encode() instead.

PyUnicode_READY(): Unneeded since Python 3.12

PyErr_Display(): Use PyErr_DisplayException() instead.

_PyErr_ChainExceptions(): Use _PyErr_ChainExceptions1() instead.

PyBytesObject.ob_shash member: call PyObject_Hash() instead.

PyDictObject.ma_version_tag member.

Thread Local Storage (TLS) API:

PyThread_create_key(): Use PyThread_tss_alloc() instead.

PyThread_delete_key(): Use PyThread_tss_free() instead.

PyThread_set_key_value(): Use PyThread_tss_set() instead.

PyThread_get_key_value(): Use PyThread_tss_get() instead.

PyThread_delete_key_value(): Use PyThread_tss_delete() instead.

PyThread_ReInitTLS(): Unneeded since Python 3.7.

Removed

Remove the token.h header file. There was never any public tokenizer C API. The token.h header file was only designed to be used by Python internals. (Contributed by Victor Stinner in gh-92651 [https://github.com/python/cpython/issues/92651].)

Legacy Unicode APIs have been removed. See PEP 623 [https://peps.python.org/pep-0623/] for detail.

PyUnicode_WCHAR_KIND

PyUnicode_AS_UNICODE()

PyUnicode_AsUnicode()

PyUnicode_AsUnicodeAndSize()

PyUnicode_AS_DATA()

PyUnicode_FromUnicode()

PyUnicode_GET_SIZE()

PyUnicode_GetSize()

PyUnicode_GET_DATA_SIZE()

Remove the PyUnicode_InternImmortal() function macro. (Contributed by Victor Stinner in gh-85858 [https://github.com/python/cpython/issues/85858].)

What’s New In Python 3.11

Editor:

Pablo Galindo Salgado

This article explains the new features in Python 3.11, compared to 3.10. Python 3.11 was released on October 24, 2022. For full details, see the changelog.

Summary – Release highlights

Python 3.11 is between 10-60% faster than Python 3.10. On average, we measured a 1.25x speedup on the standard benchmark suite. See Faster CPython for details.

New syntax features:

PEP 654: Exception Groups and except*

New built-in features:

PEP 678: Exceptions can be enriched with notes

New standard library modules:

PEP 680 [https://peps.python.org/pep-0680/]: tomllib — Support for parsing TOML [https://toml.io/] in the Standard Library

Interpreter improvements:

PEP 657: Fine-grained error locations in tracebacks

New -P command line option and PYTHONSAFEPATH environment variable to disable automatically prepending potentially unsafe paths to sys.path

New typing features:

PEP 646: Variadic generics

PEP 655: Marking individual TypedDict items as required or not-required

PEP 673: Self type

PEP 675: Arbitrary literal string type

PEP 681: Data class transforms

Important deprecations, removals and restrictions:

PEP 594 [https://peps.python.org/pep-0594/]: Many legacy standard library modules have been deprecated and will be removed in Python 3.13

PEP 624 [https://peps.python.org/pep-0624/]: Py_UNICODE encoder APIs have been removed

PEP 670 [https://peps.python.org/pep-0670/]: Macros converted to static inline functions

New Features

PEP 657: Fine-grained error locations in tracebacks

When printing tracebacks, the interpreter will now point to the exact expression that caused the error, instead of just the line. For example:

Traceback (most recent call last):
  File "distance.py", line 11, in <module>
    print(manhattan_distance(p1, p2))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "distance.py", line 6, in manhattan_distance
    return abs(point_1.x - point_2.x) + abs(point_1.y - point_2.y)
                           ^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'x'

Previous versions of the interpreter would point to just the line, making it ambiguous which object was None. These enhanced errors can also be helpful when dealing with deeply nested dict objects and multiple function calls:

Traceback (most recent call last):
  File "query.py", line 37, in <module>
    magic_arithmetic('foo')
  File "query.py", line 18, in magic_arithmetic
    return add_counts(x) / 25
           ^^^^^^^^^^^^^
  File "query.py", line 24, in add_counts
    return 25 + query_user(user1) + query_user(user2)
                ^^^^^^^^^^^^^^^^^
  File "query.py", line 32, in query_user
    return 1 + query_count(db, response['a']['b']['c']['user'], retry=True)
                               ~~~~~~~~~~~~~~~~~~^^^^^
TypeError: 'NoneType' object is not subscriptable

As well as complex arithmetic expressions:

Traceback (most recent call last):
  File "calculation.py", line 54, in <module>
    result = (x / y / z) * (a / b / c)
              ~~~~~~^~~
ZeroDivisionError: division by zero

Additionally, the information used by the enhanced traceback feature is made available via a general API, that can be used to correlate bytecode instructions with source code location. This information can be retrieved using:

The codeobject.co_positions() method in Python.

The PyCode_Addr2Location() function in the C API.

See PEP 657 [https://peps.python.org/pep-0657/] for more details. (Contributed by Pablo Galindo, Batuhan Taskaya and Ammar Askar in bpo-43950 [https://bugs.python.org/issue?@action=redirect&bpo=43950].)

참고

This feature requires storing column positions in 코드 객체, which may result in a small increase in interpreter memory usage and disk usage for compiled Python files. To avoid storing the extra information and deactivate printing the extra traceback information, use the -X no_debug_ranges command line option or the PYTHONNODEBUGRANGES environment variable.

PEP 654: Exception Groups and except*

PEP 654 [https://peps.python.org/pep-0654/] introduces language features that enable a program to raise and handle multiple unrelated exceptions simultaneously. The builtin types ExceptionGroup and BaseExceptionGroup make it possible to group exceptions and raise them together, and the new except* syntax generalizes except to match subgroups of exception groups.

See PEP 654 [https://peps.python.org/pep-0654/] for more details.

(Contributed by Irit Katriel in bpo-45292 [https://bugs.python.org/issue?@action=redirect&bpo=45292]. PEP written by Irit Katriel, Yury Selivanov and Guido van Rossum.)

PEP 678: Exceptions can be enriched with notes

The add_note() method is added to BaseException. It can be used to enrich exceptions with context information that is not available at the time when the exception is raised. The added notes appear in the default traceback.

See PEP 678 [https://peps.python.org/pep-0678/] for more details.

(Contributed by Irit Katriel in bpo-45607 [https://bugs.python.org/issue?@action=redirect&bpo=45607]. PEP written by Zac Hatfield-Dodds.)

Windows py.exe launcher improvements

The copy of the 윈도우 용 파이썬 런처 included with Python 3.11 has been significantly updated. It now supports company/tag syntax as defined in PEP 514 [https://peps.python.org/pep-0514/] using the -V:<company>/<tag> argument instead of the limited -<major>.<minor>. This allows launching distributions other than PythonCore, the one hosted on python.org [https://www.python.org].

When using -V: selectors, either company or tag can be omitted, but all installs will be searched. For example, -V:OtherPython/ will select the “best” tag registered for OtherPython, while -V:3.11 or -V:/3.11 will select the “best” distribution with tag 3.11.

When using the legacy -<major>, -<major>.<minor>, -<major>-<bitness> or -<major>.<minor>-<bitness> arguments, all existing behaviour should be preserved from past versions, and only releases from PythonCore will be selected. However, the -64 suffix now implies “not 32-bit” (not necessarily x86-64), as there are multiple supported 64-bit platforms. 32-bit runtimes are detected by checking the runtime’s tag for a -32 suffix. All releases of Python since 3.5 have included this in their 32-bit builds.

New Features Related to Type Hints

This section covers major changes affecting PEP 484 [https://peps.python.org/pep-0484/] type hints and the typing module.

PEP 646: Variadic generics

PEP 484 [https://peps.python.org/pep-0484/] previously introduced TypeVar, enabling creation of generics parameterised with a single type. PEP 646 [https://peps.python.org/pep-0646/] adds TypeVarTuple, enabling parameterisation with an arbitrary number of types. In other words, a TypeVarTuple is a variadic type variable, enabling variadic generics.

This enables a wide variety of use cases. In particular, it allows the type of array-like structures in numerical computing libraries such as NumPy and TensorFlow to be parameterised with the array shape. Static type checkers will now be able to catch shape-related bugs in code that uses these libraries.

See PEP 646 [https://peps.python.org/pep-0646/] for more details.

(Contributed by Matthew Rahtz in bpo-43224 [https://bugs.python.org/issue?@action=redirect&bpo=43224], with contributions by Serhiy Storchaka and Jelle Zijlstra. PEP written by Mark Mendoza, Matthew Rahtz, Pradeep Kumar Srinivasan, and Vincent Siles.)

PEP 655: Marking individual TypedDict items as required or not-required

Required and NotRequired provide a straightforward way to mark whether individual items in a TypedDict must be present. Previously, this was only possible using inheritance.

All fields are still required by default, unless the total parameter is set to False, in which case all fields are still not-required by default. For example, the following specifies a TypedDict with one required and one not-required key:

class Movie(TypedDict):
   title: str
   year: NotRequired[int]

m1: Movie = {"title": "Black Panther", "year": 2018}  # OK
m2: Movie = {"title": "Star Wars"}  # OK (year is not required)
m3: Movie = {"year": 2022}  # ERROR (missing required field title)

The following definition is equivalent:

class Movie(TypedDict, total=False):
   title: Required[str]
   year: int

See PEP 655 [https://peps.python.org/pep-0655/] for more details.

(Contributed by David Foster and Jelle Zijlstra in bpo-47087 [https://bugs.python.org/issue?@action=redirect&bpo=47087]. PEP written by David Foster.)

PEP 673: Self type

The new Self annotation provides a simple and intuitive way to annotate methods that return an instance of their class. This behaves the same as the TypeVar-based approach specified in PEP 484 [https://peps.python.org/pep-0484/#annotating-instance-and-class-methods], but is more concise and easier to follow.

Common use cases include alternative constructors provided as classmethods, and __enter__() methods that return self:

class MyLock:
    def __enter__(self) -> Self:
        self.lock()
        return self

    ...

class MyInt:
    @classmethod
    def fromhex(cls, s: str) -> Self:
        return cls(int(s, 16))

    ...

Self can also be used to annotate method parameters or attributes of the same type as their enclosing class.

See PEP 673 [https://peps.python.org/pep-0673/] for more details.

(Contributed by James Hilton-Balfe in bpo-46534 [https://bugs.python.org/issue?@action=redirect&bpo=46534]. PEP written by Pradeep Kumar Srinivasan and James Hilton-Balfe.)

PEP 675: Arbitrary literal string type

The new LiteralString annotation may be used to indicate that a function parameter can be of any literal string type. This allows a function to accept arbitrary literal string types, as well as strings created from other literal strings. Type checkers can then enforce that sensitive functions, such as those that execute SQL statements or shell commands, are called only with static arguments, providing protection against injection attacks.

For example, a SQL query function could be annotated as follows:

def run_query(sql: LiteralString) -> ...
    ...

def caller(
    arbitrary_string: str,
    query_string: LiteralString,
    table_name: LiteralString,
) -> None:
    run_query("SELECT * FROM students")       # ok
    run_query(query_string)                   # ok
    run_query("SELECT * FROM " + table_name)  # ok
    run_query(arbitrary_string)               # type checker error
    run_query(                                # type checker error
        f"SELECT * FROM students WHERE name = {arbitrary_string}"
    )

See PEP 675 [https://peps.python.org/pep-0675/] for more details.

(Contributed by Jelle Zijlstra in bpo-47088 [https://bugs.python.org/issue?@action=redirect&bpo=47088]. PEP written by Pradeep Kumar Srinivasan and Graham Bleaney.)

PEP 681: Data class transforms

dataclass_transform may be used to decorate a class, metaclass, or a function that is itself a decorator. The presence of @dataclass_transform() tells a static type checker that the decorated object performs runtime “magic” that transforms a class, giving it dataclass-like behaviors.

For example:

# The create_model decorator is defined by a library.
@typing.dataclass_transform()
def create_model(cls: Type[T]) -> Type[T]:
    cls.__init__ = ...
    cls.__eq__ = ...
    cls.__ne__ = ...
    return cls

# The create_model decorator can now be used to create new model classes:
@create_model
class CustomerModel:
    id: int
    name: str

c = CustomerModel(id=327, name="Eric Idle")

See PEP 681 [https://peps.python.org/pep-0681/] for more details.

(Contributed by Jelle Zijlstra in gh-91860 [https://github.com/python/cpython/issues/91860]. PEP written by Erik De Bonte and Eric Traut.)

PEP 563 may not be the future

PEP 563 [https://peps.python.org/pep-0563/] Postponed Evaluation of Annotations (the from __future__ import annotations future statement) that was originally planned for release in Python 3.10 has been put on hold indefinitely. See this message from the Steering Council [https://mail.python.org/archives/list/python-dev@python.org/message/VIZEBX5EYMSYIJNDBF6DMUMZOCWHARSO/] for more information.

Other Language Changes

Starred unpacking expressions can now be used in for statements. (See bpo-46725 [https://bugs.python.org/issue?@action=redirect&bpo=46725] for more details.)

Asynchronous comprehensions are now allowed inside comprehensions in asynchronous functions. Outer comprehensions implicitly become asynchronous in this case. (Contributed by Serhiy Storchaka in bpo-33346 [https://bugs.python.org/issue?@action=redirect&bpo=33346].)

A TypeError is now raised instead of an AttributeError in with statements and contextlib.ExitStack.enter_context() for objects that do not support the context manager protocol, and in async with statements and contextlib.AsyncExitStack.enter_async_context() for objects not supporting the asynchronous context manager protocol. (Contributed by Serhiy Storchaka in bpo-12022 [https://bugs.python.org/issue?@action=redirect&bpo=12022] and bpo-44471 [https://bugs.python.org/issue?@action=redirect&bpo=44471].)

Added object.__getstate__(), which provides the default implementation of the __getstate__() method. copying and pickleing instances of subclasses of builtin types bytearray, set, frozenset, collections.OrderedDict, collections.deque, weakref.WeakSet, and datetime.tzinfo now copies and pickles instance attributes implemented as slots. This change has an unintended side effect: It trips up a small minority of existing Python projects not expecting object.__getstate__() to exist. See the later comments on gh-70766 [https://github.com/python/cpython/issues/70766] for discussions of what workarounds such code may need. (Contributed by Serhiy Storchaka in bpo-26579 [https://bugs.python.org/issue?@action=redirect&bpo=26579].)

Added a -P command line option and a PYTHONSAFEPATH environment variable, which disable the automatic prepending to sys.path of the script’s directory when running a script, or the current directory when using -c and -m. This ensures only stdlib and installed modules are picked up by import, and avoids unintentionally or maliciously shadowing modules with those in a local (and typically user-writable) directory. (Contributed by Victor Stinner in gh-57684 [https://github.com/python/cpython/issues/57684].)

A "z" option was added to the 포맷 명세 미니 언어 that coerces negative to positive zero after rounding to the format precision. See PEP 682 [https://peps.python.org/pep-0682/] for more details. (Contributed by John Belmonte in gh-90153 [https://github.com/python/cpython/issues/90153].)

Bytes are no longer accepted on sys.path. Support broke sometime between Python 3.2 and 3.6, with no one noticing until after Python 3.10.0 was released. In addition, bringing back support would be problematic due to interactions between -b and sys.path_importer_cache when there is a mixture of str and bytes keys. (Contributed by Thomas Grainger in gh-91181 [https://github.com/python/cpython/issues/91181].)

Other CPython Implementation Changes

The special methods __complex__() for complex and __bytes__() for bytes are implemented to support the typing.SupportsComplex and typing.SupportsBytes protocols. (Contributed by Mark Dickinson and Donghee Na in bpo-24234 [https://bugs.python.org/issue?@action=redirect&bpo=24234].)

siphash13 is added as a new internal hashing algorithm. It has similar security properties as siphash24, but it is slightly faster for long inputs. str, bytes, and some other types now use it as the default algorithm for hash(). PEP 552 [https://peps.python.org/pep-0552/] hash-based .pyc files now use siphash13 too. (Contributed by Inada Naoki in bpo-29410 [https://bugs.python.org/issue?@action=redirect&bpo=29410].)

When an active exception is re-raised by a raise statement with no parameters, the traceback attached to this exception is now always sys.exc_info()[1].__traceback__. This means that changes made to the traceback in the current except clause are reflected in the re-raised exception. (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

The interpreter state’s representation of handled exceptions (aka exc_info or _PyErr_StackItem) now only has the exc_value field; exc_type and exc_traceback have been removed, as they can be derived from exc_value. (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

A new command line option, AppendPath, has been added for the Windows installer. It behaves similarly to PrependPath, but appends the install and scripts directories instead of prepending them. (Contributed by Bastian Neuburger in bpo-44934 [https://bugs.python.org/issue?@action=redirect&bpo=44934].)

The PyConfig.module_search_paths_set field must now be set to 1 for initialization to use PyConfig.module_search_paths to initialize sys.path. Otherwise, initialization will recalculate the path and replace any values added to module_search_paths.

The output of the --help option now fits in 50 lines/80 columns. Information about Python environment variables and -X options is now available using the respective --help-env and --help-xoptions flags, and with the new --help-all. (Contributed by Éric Araujo in bpo-46142 [https://bugs.python.org/issue?@action=redirect&bpo=46142].)

Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735]. This limit can be configured or disabled by environment variable, command line flag, or sys APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.

New Modules

tomllib: For parsing TOML [https://toml.io/]. See PEP 680 [https://peps.python.org/pep-0680/] for more details. (Contributed by Taneli Hukkinen in bpo-40059 [https://bugs.python.org/issue?@action=redirect&bpo=40059].)

wsgiref.types: WSGI [https://peps.python.org/pep-3333/]-specific types for static type checking. (Contributed by Sebastian Rittau in bpo-42012 [https://bugs.python.org/issue?@action=redirect&bpo=42012].)

Improved Modules

asyncio

Added the TaskGroup class, an asynchronous context manager holding a group of tasks that will wait for all of them upon exit. For new code this is recommended over using create_task() and gather() directly. (Contributed by Yury Selivanov and others in gh-90908 [https://github.com/python/cpython/issues/90908].)

Added timeout(), an asynchronous context manager for setting a timeout on asynchronous operations. For new code this is recommended over using wait_for() directly. (Contributed by Andrew Svetlov in gh-90927 [https://github.com/python/cpython/issues/90927].)

Added the Runner class, which exposes the machinery used by run(). (Contributed by Andrew Svetlov in gh-91218 [https://github.com/python/cpython/issues/91218].)

Added the Barrier class to the synchronization primitives in the asyncio library, and the related BrokenBarrierError exception. (Contributed by Yves Duprat and Andrew Svetlov in gh-87518 [https://github.com/python/cpython/issues/87518].)

Added keyword argument all_errors to asyncio.loop.create_connection() so that multiple connection errors can be raised as an ExceptionGroup.

Added the asyncio.StreamWriter.start_tls() method for upgrading existing stream-based connections to TLS. (Contributed by Ian Good in bpo-34975 [https://bugs.python.org/issue?@action=redirect&bpo=34975].)

Added raw datagram socket functions to the event loop: sock_sendto(), sock_recvfrom() and sock_recvfrom_into(). These have implementations in SelectorEventLoop and ProactorEventLoop. (Contributed by Alex Grönholm in bpo-46805 [https://bugs.python.org/issue?@action=redirect&bpo=46805].)

Added cancelling() and uncancel() methods to Task. These are primarily intended for internal use, notably by TaskGroup.

contextlib

Added non parallel-safe chdir() context manager to change the current working directory and then restore it on exit. Simple wrapper around chdir(). (Contributed by Filipe Laíns in bpo-25625 [https://bugs.python.org/issue?@action=redirect&bpo=25625])

dataclasses

Change field default mutability check, allowing only defaults which are hashable instead of any object which is not an instance of dict, list or set. (Contributed by Eric V. Smith in bpo-44674 [https://bugs.python.org/issue?@action=redirect&bpo=44674].)

datetime

Add datetime.UTC, a convenience alias for datetime.timezone.utc. (Contributed by Kabir Kwatra in gh-91973 [https://github.com/python/cpython/issues/91973].)

datetime.date.fromisoformat(), datetime.time.fromisoformat() and datetime.datetime.fromisoformat() can now be used to parse most ISO 8601 formats (barring only those that support fractional hours and minutes). (Contributed by Paul Ganssle in gh-80010 [https://github.com/python/cpython/issues/80010].)

enum

Renamed EnumMeta to EnumType (EnumMeta kept as an alias).

Added StrEnum, with members that can be used as (and must be) strings.

Added ReprEnum, which only modifies the __repr__() of members while returning their literal values (rather than names) for __str__() and __format__() (used by str(), format() and f-strings).

Changed Enum.__format__() (the default for format(), str.format() and f-strings) to always produce the same result as Enum.__str__(): for enums inheriting from ReprEnum it will be the member’s value; for all other enums it will be the enum and member name (e.g. Color.RED).

Added a new boundary class parameter to Flag enums and the FlagBoundary enum with its options, to control how to handle out-of-range flag values.

Added the verify() enum decorator and the EnumCheck enum with its options, to check enum classes against several specific constraints.

Added the member() and nonmember() decorators, to ensure the decorated object is/is not converted to an enum member.

Added the property() decorator, which works like property() except for enums. Use this instead of types.DynamicClassAttribute().

Added the global_enum() enum decorator, which adjusts __repr__() and __str__() to show values as members of their module rather than the enum class. For example, 're.ASCII' for the ASCII member of re.RegexFlag rather than 'RegexFlag.ASCII'.

Enhanced Flag to support len(), iteration and in/not in on its members. For example, the following now works: len(AFlag(3)) == 2 and list(AFlag(3)) == (AFlag.ONE, AFlag.TWO)

Changed Enum and Flag so that members are now defined before __init_subclass__() is called; dir() now includes methods, etc., from mixed-in data types.

Changed Flag to only consider primary values (power of two) canonical while composite values (3, 6, 10, etc.) are considered aliases; inverted flags are coerced to their positive equivalent.

fcntl

On FreeBSD, the F_DUP2FD and F_DUP2FD_CLOEXEC flags respectively are supported, the former equals to dup2 usage while the latter set the FD_CLOEXEC flag in addition.

fractions

Support PEP 515 [https://peps.python.org/pep-0515/]-style initialization of Fraction from string. (Contributed by Sergey B Kirpichev in bpo-44258 [https://bugs.python.org/issue?@action=redirect&bpo=44258].)

Fraction now implements an __int__ method, so that an isinstance(some_fraction, typing.SupportsInt) check passes. (Contributed by Mark Dickinson in bpo-44547 [https://bugs.python.org/issue?@action=redirect&bpo=44547].)

functools

functools.singledispatch() now supports types.UnionType and typing.Union as annotations to the dispatch argument.:

>>> from functools import singledispatch
>>> @singledispatch
... def fun(arg, verbose=False):
...     if verbose:
...         print("Let me just say,", end=" ")
...     print(arg)
...
>>> @fun.register
... def _(arg: int | float, verbose=False):
...     if verbose:
...         print("Strength in numbers, eh?", end=" ")
...     print(arg)
...
>>> from typing import Union
>>> @fun.register
... def _(arg: Union[list, set], verbose=False):
...     if verbose:
...         print("Enumerate this:")
...     for i, elem in enumerate(arg):
...         print(i, elem)
...

(Contributed by Yurii Karabas in bpo-46014 [https://bugs.python.org/issue?@action=redirect&bpo=46014].)

gzip

The gzip.compress() function is now faster when used with the mtime=0 argument as it delegates the compression entirely to a single zlib.compress() operation. There is one side effect of this change: The gzip file header contains an “OS” byte in its header. That was traditionally always set to a value of 255 representing “unknown” by the gzip module. Now, when using compress() with mtime=0, it may be set to a different value by the underlying zlib C library Python was linked against. (See gh-112346 [https://github.com/python/cpython/issues/112346] for details on the side effect.)

hashlib

hashlib.blake2b() and hashlib.blake2s() now prefer libb2 [https://www.blake2.net/] over Python’s vendored copy. (Contributed by Christian Heimes in bpo-47095 [https://bugs.python.org/issue?@action=redirect&bpo=47095].)

The internal _sha3 module with SHA3 and SHAKE algorithms now uses tiny_sha3 instead of the Keccak Code Package to reduce code and binary size. The hashlib module prefers optimized SHA3 and SHAKE implementations from OpenSSL. The change affects only installations without OpenSSL support. (Contributed by Christian Heimes in bpo-47098 [https://bugs.python.org/issue?@action=redirect&bpo=47098].)

Add hashlib.file_digest(), a helper function for efficient hashing of files or file-like objects. (Contributed by Christian Heimes in gh-89313 [https://github.com/python/cpython/issues/89313].)

IDLE and idlelib

Apply syntax highlighting to .pyi files. (Contributed by Alex Waygood and Terry Jan Reedy in bpo-45447 [https://bugs.python.org/issue?@action=redirect&bpo=45447].)

Include prompts when saving Shell with inputs and outputs. (Contributed by Terry Jan Reedy in gh-95191 [https://github.com/python/cpython/issues/95191].)

inspect

Add getmembers_static() to return all members without triggering dynamic lookup via the descriptor protocol. (Contributed by Weipeng Hong in bpo-30533 [https://bugs.python.org/issue?@action=redirect&bpo=30533].)

Add ismethodwrapper() for checking if the type of an object is a MethodWrapperType. (Contributed by Hakan Çelik in bpo-29418 [https://bugs.python.org/issue?@action=redirect&bpo=29418].)

Change the frame-related functions in the inspect module to return new FrameInfo and Traceback class instances (backwards compatible with the previous named tuple-like interfaces) that includes the extended PEP 657 [https://peps.python.org/pep-0657/] position information (end line number, column and end column). The affected functions are:

inspect.getframeinfo()

inspect.getouterframes()

inspect.getinnerframes(),

inspect.stack()

inspect.trace()

(Contributed by Pablo Galindo in gh-88116 [https://github.com/python/cpython/issues/88116].)

locale

Add locale.getencoding() to get the current locale encoding. It is similar to locale.getpreferredencoding(False) but ignores the Python UTF-8 Mode.

logging

Added getLevelNamesMapping() to return a mapping from logging level names (e.g. 'CRITICAL') to the values of their corresponding 로깅 수준 (e.g. 50, by default). (Contributed by Andrei Kulakovin in gh-88024 [https://github.com/python/cpython/issues/88024].)

Added a createSocket() method to SysLogHandler, to match SocketHandler.createSocket(). It is called automatically during handler initialization and when emitting an event, if there is no active socket. (Contributed by Kirill Pinchuk in gh-88457 [https://github.com/python/cpython/issues/88457].)

math

Add math.exp2(): return 2 raised to the power of x. (Contributed by Gideon Mitchell in bpo-45917 [https://bugs.python.org/issue?@action=redirect&bpo=45917].)

Add math.cbrt(): return the cube root of x. (Contributed by Ajith Ramachandran in bpo-44357 [https://bugs.python.org/issue?@action=redirect&bpo=44357].)

The behaviour of two math.pow() corner cases was changed, for consistency with the IEEE 754 specification. The operations math.pow(0.0, -math.inf) and math.pow(-0.0, -math.inf) now return inf. Previously they raised ValueError. (Contributed by Mark Dickinson in bpo-44339 [https://bugs.python.org/issue?@action=redirect&bpo=44339].)

The math.nan value is now always available. (Contributed by Victor Stinner in bpo-46917 [https://bugs.python.org/issue?@action=redirect&bpo=46917].)

operator

A new function operator.call has been added, such that operator.call(obj, *args, **kwargs) == obj(*args, **kwargs). (Contributed by Antony Lee in bpo-44019 [https://bugs.python.org/issue?@action=redirect&bpo=44019].)

os

On Windows, os.urandom() now uses BCryptGenRandom(), instead of CryptGenRandom() which is deprecated. (Contributed by Donghee Na in bpo-44611 [https://bugs.python.org/issue?@action=redirect&bpo=44611].)

pathlib

glob() and rglob() return only directories if pattern ends with a pathname components separator: sep or altsep. (Contributed by Eisuke Kawasima in bpo-22276 [https://bugs.python.org/issue?@action=redirect&bpo=22276] and bpo-33392 [https://bugs.python.org/issue?@action=redirect&bpo=33392].)

re

Atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) are now supported in regular expressions. (Contributed by Jeffrey C. Jacobs and Serhiy Storchaka in bpo-433030 [https://bugs.python.org/issue?@action=redirect&bpo=433030].)

shutil

Add optional parameter dir_fd in shutil.rmtree(). (Contributed by Serhiy Storchaka in bpo-46245 [https://bugs.python.org/issue?@action=redirect&bpo=46245].)

socket

Add CAN Socket support for NetBSD. (Contributed by Thomas Klausner in bpo-30512 [https://bugs.python.org/issue?@action=redirect&bpo=30512].)

create_connection() has an option to raise, in case of failure to connect, an ExceptionGroup containing all errors instead of only raising the last error. (Contributed by Irit Katriel in bpo-29980 [https://bugs.python.org/issue?@action=redirect&bpo=29980].)

sqlite3

You can now disable the authorizer by passing None to set_authorizer(). (Contributed by Erlend E. Aasland in bpo-44491 [https://bugs.python.org/issue?@action=redirect&bpo=44491].)

Collation name create_collation() can now contain any Unicode character. Collation names with invalid characters now raise UnicodeEncodeError instead of sqlite3.ProgrammingError. (Contributed by Erlend E. Aasland in bpo-44688 [https://bugs.python.org/issue?@action=redirect&bpo=44688].)

sqlite3 exceptions now include the SQLite extended error code as sqlite_errorcode and the SQLite error name as sqlite_errorname. (Contributed by Aviv Palivoda, Daniel Shahaf, and Erlend E. Aasland in bpo-16379 [https://bugs.python.org/issue?@action=redirect&bpo=16379] and bpo-24139 [https://bugs.python.org/issue?@action=redirect&bpo=24139].)

Add setlimit() and getlimit() to sqlite3.Connection for setting and getting SQLite limits by connection basis. (Contributed by Erlend E. Aasland in bpo-45243 [https://bugs.python.org/issue?@action=redirect&bpo=45243].)

sqlite3 now sets sqlite3.threadsafety based on the default threading mode the underlying SQLite library has been compiled with. (Contributed by Erlend E. Aasland in bpo-45613 [https://bugs.python.org/issue?@action=redirect&bpo=45613].)

sqlite3 C callbacks now use unraisable exceptions if callback tracebacks are enabled. Users can now register an unraisable hook handler to improve their debug experience. (Contributed by Erlend E. Aasland in bpo-45828 [https://bugs.python.org/issue?@action=redirect&bpo=45828].)

Fetch across rollback no longer raises InterfaceError. Instead we leave it to the SQLite library to handle these cases. (Contributed by Erlend E. Aasland in bpo-44092 [https://bugs.python.org/issue?@action=redirect&bpo=44092].)

Add serialize() and deserialize() to sqlite3.Connection for serializing and deserializing databases. (Contributed by Erlend E. Aasland in bpo-41930 [https://bugs.python.org/issue?@action=redirect&bpo=41930].)

Add create_window_function() to sqlite3.Connection for creating aggregate window functions. (Contributed by Erlend E. Aasland in bpo-34916 [https://bugs.python.org/issue?@action=redirect&bpo=34916].)

Add blobopen() to sqlite3.Connection. sqlite3.Blob allows incremental I/O operations on blobs. (Contributed by Aviv Palivoda and Erlend E. Aasland in bpo-24905 [https://bugs.python.org/issue?@action=redirect&bpo=24905].)

string

Add get_identifiers() and is_valid() to string.Template, which respectively return all valid placeholders, and whether any invalid placeholders are present. (Contributed by Ben Kehoe in gh-90465 [https://github.com/python/cpython/issues/90465].)

sys

sys.exc_info() now derives the type and traceback fields from the value (the exception instance), so when an exception is modified while it is being handled, the changes are reflected in the results of subsequent calls to exc_info(). (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

Add sys.exception() which returns the active exception instance (equivalent to sys.exc_info()[1]). (Contributed by Irit Katriel in bpo-46328 [https://bugs.python.org/issue?@action=redirect&bpo=46328].)

Add the sys.flags.safe_path flag. (Contributed by Victor Stinner in gh-57684 [https://github.com/python/cpython/issues/57684].)

sysconfig

Three new installation schemes (posix_venv, nt_venv and venv) were added and are used when Python creates new virtual environments or when it is running from a virtual environment. The first two schemes (posix_venv and nt_venv) are OS-specific for non-Windows and Windows, the venv is essentially an alias to one of them according to the OS Python runs on. This is useful for downstream distributors who modify sysconfig.get_preferred_scheme(). Third party code that creates new virtual environments should use the new venv installation scheme to determine the paths, as does venv. (Contributed by Miro Hrončok in bpo-45413 [https://bugs.python.org/issue?@action=redirect&bpo=45413].)

tempfile

SpooledTemporaryFile objects now fully implement the methods of io.BufferedIOBase or io.TextIOBase (depending on file mode). This lets them work correctly with APIs that expect file-like objects, such as compression modules. (Contributed by Carey Metcalfe in gh-70363 [https://github.com/python/cpython/issues/70363].)

threading

On Unix, if the sem_clockwait() function is available in the C library (glibc 2.30 and newer), the threading.Lock.acquire() method now uses the monotonic clock (time.CLOCK_MONOTONIC) for the timeout, rather than using the system clock (time.CLOCK_REALTIME), to not be affected by system clock changes. (Contributed by Victor Stinner in bpo-41710 [https://bugs.python.org/issue?@action=redirect&bpo=41710].)

time

On Unix, time.sleep() now uses the clock_nanosleep() or nanosleep() function, if available, which has a resolution of 1 nanosecond (10⁻⁹ seconds), rather than using select() which has a resolution of 1 microsecond (10⁻⁶ seconds). (Contributed by Benjamin Szőke and Victor Stinner in bpo-21302 [https://bugs.python.org/issue?@action=redirect&bpo=21302].)

On Windows 8.1 and newer, time.sleep() now uses a waitable timer based on high-resolution timers [https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/high-resolution-timers] which has a resolution of 100 nanoseconds (10⁻⁷ seconds). Previously, it had a resolution of 1 millisecond (10⁻³ seconds). (Contributed by Benjamin Szőke, Donghee Na, Eryk Sun and Victor Stinner in bpo-21302 [https://bugs.python.org/issue?@action=redirect&bpo=21302] and bpo-45429 [https://bugs.python.org/issue?@action=redirect&bpo=45429].)

tkinter

Added method info_patchlevel() which returns the exact version of the Tcl library as a named tuple similar to sys.version_info. (Contributed by Serhiy Storchaka in gh-91827 [https://github.com/python/cpython/issues/91827].)

traceback

Add traceback.StackSummary.format_frame_summary() to allow users to override which frames appear in the traceback, and how they are formatted. (Contributed by Ammar Askar in bpo-44569 [https://bugs.python.org/issue?@action=redirect&bpo=44569].)

Add traceback.TracebackException.print(), which prints the formatted TracebackException instance to a file. (Contributed by Irit Katriel in bpo-33809 [https://bugs.python.org/issue?@action=redirect&bpo=33809].)

typing

For major changes, see New Features Related to Type Hints.

Add typing.assert_never() and typing.Never. typing.assert_never() is useful for asking a type checker to confirm that a line of code is not reachable. At runtime, it raises an AssertionError. (Contributed by Jelle Zijlstra in gh-90633 [https://github.com/python/cpython/issues/90633].)

Add typing.reveal_type(). This is useful for asking a type checker what type it has inferred for a given expression. At runtime it prints the type of the received value. (Contributed by Jelle Zijlstra in gh-90572 [https://github.com/python/cpython/issues/90572].)

Add typing.assert_type(). This is useful for asking a type checker to confirm that the type it has inferred for a given expression matches the given type. At runtime it simply returns the received value. (Contributed by Jelle Zijlstra in gh-90638 [https://github.com/python/cpython/issues/90638].)

typing.TypedDict types can now be generic. (Contributed by Samodya Abeysiriwardane in gh-89026 [https://github.com/python/cpython/issues/89026].)

NamedTuple types can now be generic. (Contributed by Serhiy Storchaka in bpo-43923 [https://bugs.python.org/issue?@action=redirect&bpo=43923].)

Allow subclassing of typing.Any. This is useful for avoiding type checker errors related to highly dynamic class, such as mocks. (Contributed by Shantanu Jain in gh-91154 [https://github.com/python/cpython/issues/91154].)

The typing.final() decorator now sets the __final__ attributed on the decorated object. (Contributed by Jelle Zijlstra in gh-90500 [https://github.com/python/cpython/issues/90500].)

The typing.get_overloads() function can be used for introspecting the overloads of a function. typing.clear_overloads() can be used to clear all registered overloads of a function. (Contributed by Jelle Zijlstra in gh-89263 [https://github.com/python/cpython/issues/89263].)

The __init__() method of Protocol subclasses is now preserved. (Contributed by Adrian Garcia Badarasco in gh-88970 [https://github.com/python/cpython/issues/88970].)

The representation of empty tuple types (Tuple[()]) is simplified. This affects introspection, e.g. get_args(Tuple[()]) now evaluates to () instead of ((),). (Contributed by Serhiy Storchaka in gh-91137 [https://github.com/python/cpython/issues/91137].)

Loosen runtime requirements for type annotations by removing the callable check in the private typing._type_check function. (Contributed by Gregory Beauregard in gh-90802 [https://github.com/python/cpython/issues/90802].)

typing.get_type_hints() now supports evaluating strings as forward references in PEP 585 generic aliases. (Contributed by Niklas Rosenstein in gh-85542 [https://github.com/python/cpython/issues/85542].)

typing.get_type_hints() no longer adds Optional to parameters with None as a default. (Contributed by Nikita Sobolev in gh-90353 [https://github.com/python/cpython/issues/90353].)

typing.get_type_hints() now supports evaluating bare stringified ClassVar annotations. (Contributed by Gregory Beauregard in gh-90711 [https://github.com/python/cpython/issues/90711].)

typing.no_type_check() no longer modifies external classes and functions. It also now correctly marks classmethods as not to be type checked. (Contributed by Nikita Sobolev in gh-90729 [https://github.com/python/cpython/issues/90729].)

unicodedata

The Unicode database has been updated to version 14.0.0. (Contributed by Benjamin Peterson in bpo-45190 [https://bugs.python.org/issue?@action=redirect&bpo=45190]).

unittest

Added methods enterContext() and enterClassContext() of class TestCase, method enterAsyncContext() of class IsolatedAsyncioTestCase and function unittest.enterModuleContext(). (Contributed by Serhiy Storchaka in bpo-45046 [https://bugs.python.org/issue?@action=redirect&bpo=45046].)

venv

When new Python virtual environments are created, the venv sysconfig installation scheme is used to determine the paths inside the environment. When Python runs in a virtual environment, the same installation scheme is the default. That means that downstream distributors can change the default sysconfig install scheme without changing behavior of virtual environments. Third party code that also creates new virtual environments should do the same. (Contributed by Miro Hrončok in bpo-45413 [https://bugs.python.org/issue?@action=redirect&bpo=45413].)

warnings

warnings.catch_warnings() now accepts arguments for warnings.simplefilter(), providing a more concise way to locally ignore warnings or convert them to errors. (Contributed by Zac Hatfield-Dodds in bpo-47074 [https://bugs.python.org/issue?@action=redirect&bpo=47074].)

zipfile

Added support for specifying member name encoding for reading metadata in a ZipFile’s directory and file headers. (Contributed by Stephen J. Turnbull and Serhiy Storchaka in bpo-28080 [https://bugs.python.org/issue?@action=redirect&bpo=28080].)

Added ZipFile.mkdir() for creating new directories inside ZIP archives. (Contributed by Sam Ezeh in gh-49083 [https://github.com/python/cpython/issues/49083].)

Added stem, suffix and suffixes to zipfile.Path. (Contributed by Miguel Brito in gh-88261 [https://github.com/python/cpython/issues/88261].)

Optimizations

This section covers specific optimizations independent of the Faster CPython project, which is covered in its own section.

The compiler now optimizes simple printf-style % formatting on string literals containing only the format codes %s, %r and %a and makes it as fast as a corresponding f-string expression. (Contributed by Serhiy Storchaka in bpo-28307 [https://bugs.python.org/issue?@action=redirect&bpo=28307].)

Integer division (//) is better tuned for optimization by compilers. It is now around 20% faster on x86-64 when dividing an int by a value smaller than 2**30. (Contributed by Gregory P. Smith and Tim Peters in gh-90564 [https://github.com/python/cpython/issues/90564].)

sum() is now nearly 30% faster for integers smaller than 2**30. (Contributed by Stefan Behnel in gh-68264 [https://github.com/python/cpython/issues/68264].)

Resizing lists is streamlined for the common case, speeding up list.append() by ≈15% and simple list comprehensions by up to 20-30% (Contributed by Dennis Sweeney in gh-91165 [https://github.com/python/cpython/issues/91165].)

Dictionaries don’t store hash values when all keys are Unicode objects, decreasing dict size. For example, sys.getsizeof(dict.fromkeys("abcdefg")) is reduced from 352 bytes to 272 bytes (23% smaller) on 64-bit platforms. (Contributed by Inada Naoki in bpo-46845 [https://bugs.python.org/issue?@action=redirect&bpo=46845].)

Using asyncio.DatagramProtocol is now orders of magnitude faster when transferring large files over UDP, with speeds over 100 times higher for a ≈60 MiB file. (Contributed by msoxzw in gh-91487 [https://github.com/python/cpython/issues/91487].)

math functions comb() and perm() are now ≈10 times faster for large arguments (with a larger speedup for larger k). (Contributed by Serhiy Storchaka in bpo-37295 [https://bugs.python.org/issue?@action=redirect&bpo=37295].)

The statistics functions mean(), variance() and stdev() now consume iterators in one pass rather than converting them to a list first. This is twice as fast and can save substantial memory. (Contributed by Raymond Hettinger in gh-90415 [https://github.com/python/cpython/issues/90415].)

unicodedata.normalize() now normalizes pure-ASCII strings in constant time. (Contributed by Donghee Na in bpo-44987 [https://bugs.python.org/issue?@action=redirect&bpo=44987].)

Faster CPython

CPython 3.11 is an average of 25% faster [https://github.com/faster-cpython/ideas#published-results] than CPython 3.10 as measured with the pyperformance [https://github.com/python/pyperformance] benchmark suite, when compiled with GCC on Ubuntu Linux. Depending on your workload, the overall speedup could be 10-60%.

This project focuses on two major areas in Python: Faster Startup and Faster Runtime. Optimizations not covered by this project are listed separately under Optimizations.

Faster Startup

Frozen imports / Static code objects

Python caches bytecode in the __pycache__ directory to speed up module loading.

Previously in 3.10, Python module execution looked like this:

Read __pycache__ -> Unmarshal -> Heap allocated code object -> Evaluate

In Python 3.11, the core modules essential for Python startup are “frozen”. This means that their 코드 객체 (and bytecode) are statically allocated by the interpreter. This reduces the steps in module execution process to:

Statically allocated code object -> Evaluate

Interpreter startup is now 10-15% faster in Python 3.11. This has a big impact for short-running programs using Python.

(Contributed by Eric Snow, Guido van Rossum and Kumar Aditya in many issues.)

Faster Runtime

Cheaper, lazy Python frames

Python frames, holding execution information, are created whenever Python calls a Python function. The following are new frame optimizations:

Streamlined the frame creation process.

Avoided memory allocation by generously re-using frame space on the C stack.

Streamlined the internal frame struct to contain only essential information. Frames previously held extra debugging and memory management information.

Old-style frame objects are now created only when requested by debuggers or by Python introspection functions such as sys._getframe() and inspect.currentframe(). For most user code, no frame objects are created at all. As a result, nearly all Python functions calls have sped up significantly. We measured a 3-7% speedup in pyperformance.

(Contributed by Mark Shannon in bpo-44590 [https://bugs.python.org/issue?@action=redirect&bpo=44590].)

Inlined Python function calls

During a Python function call, Python will call an evaluating C function to interpret that function’s code. This effectively limits pure Python recursion to what’s safe for the C stack.

In 3.11, when CPython detects Python code calling another Python function, it sets up a new frame, and “jumps” to the new code inside the new frame. This avoids calling the C interpreting function altogether.

Most Python function calls now consume no C stack space, speeding them up. In simple recursive functions like fibonacci or factorial, we observed a 1.7x speedup. This also means recursive functions can recurse significantly deeper (if the user increases the recursion limit with sys.setrecursionlimit()). We measured a 1-3% improvement in pyperformance.

(Contributed by Pablo Galindo and Mark Shannon in bpo-45256 [https://bugs.python.org/issue?@action=redirect&bpo=45256].)

PEP 659: Specializing Adaptive Interpreter

PEP 659 [https://peps.python.org/pep-0659/] is one of the key parts of the Faster CPython project. The general idea is that while Python is a dynamic language, most code has regions where objects and types rarely change. This concept is known as type stability.

At runtime, Python will try to look for common patterns and type stability in the executing code. Python will then replace the current operation with a more specialized one. This specialized operation uses fast paths available only to those use cases/types, which generally outperform their generic counterparts. This also brings in another concept called inline caching, where Python caches the results of expensive operations directly in the bytecode.

The specializer will also combine certain common instruction pairs into one superinstruction, reducing the overhead during execution.

Python will only specialize when it sees code that is “hot” (executed multiple times). This prevents Python from wasting time on run-once code. Python can also de-specialize when code is too dynamic or when the use changes. Specialization is attempted periodically, and specialization attempts are not too expensive, allowing specialization to adapt to new circumstances.

(PEP written by Mark Shannon, with ideas inspired by Stefan Brunthaler. See PEP 659 [https://peps.python.org/pep-0659/] for more information. Implementation by Mark Shannon and Brandt Bucher, with additional help from Irit Katriel and Dennis Sweeney.)

Operation

Form

Specialization

Operation speedup (up to)

Contributor(s)

Binary operations

x + x

x - x

x * x

Binary add, multiply and subtract for common types such as int, float and str take custom fast paths for their underlying types.

10%

Mark Shannon, Donghee Na, Brandt Bucher, Dennis Sweeney

Subscript

a[i]

Subscripting container types such as list, tuple and dict directly index the underlying data structures.

Subscripting custom __getitem__() is also inlined similar to Inlined Python function calls.

10-25%

Irit Katriel, Mark Shannon

Store subscript

a[i] = z

Similar to subscripting specialization above.

10-25%

Dennis Sweeney

Calls

f(arg)

C(arg)

Calls to common builtin (C) functions and types such as len() and str directly call their underlying C version. This avoids going through the internal calling convention.

20%

Mark Shannon, Ken Jin

Load global variable

print

len

The object’s index in the globals/builtins namespace is cached. Loading globals and builtins require zero namespace lookups.

[1]

Mark Shannon

Load attribute

o.attr

Similar to loading global variables. The attribute’s index inside the class/object’s namespace is cached. In most cases, attribute loading will require zero namespace lookups.

[2]

Mark Shannon

Load methods for call

o.meth()

The actual address of the method is cached. Method loading now has no namespace lookups – even for classes with long inheritance chains.

10-20%

Ken Jin, Mark Shannon

Store attribute

o.attr = z

Similar to load attribute optimization.

2% in pyperformance

Mark Shannon

Unpack Sequence

*seq

Specialized for common containers such as list and tuple. Avoids internal calling convention.

8%

Brandt Bucher

[1]

A similar optimization already existed since Python 3.8. 3.11 specializes for more forms and reduces some overhead.

[2]

A similar optimization already existed since Python 3.10. 3.11 specializes for more forms. Furthermore, all attribute loads should be sped up by bpo-45947 [https://bugs.python.org/issue?@action=redirect&bpo=45947].

Misc

Objects now require less memory due to lazily created object namespaces. Their namespace dictionaries now also share keys more freely. (Contributed Mark Shannon in bpo-45340 [https://bugs.python.org/issue?@action=redirect&bpo=45340] and bpo-40116 [https://bugs.python.org/issue?@action=redirect&bpo=40116].)

“Zero-cost” exceptions are implemented, eliminating the cost of try statements when no exception is raised. (Contributed by Mark Shannon in bpo-40222 [https://bugs.python.org/issue?@action=redirect&bpo=40222].)

A more concise representation of exceptions in the interpreter reduced the time required for catching an exception by about 10%. (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

re’s regular expression matching engine has been partially refactored, and now uses computed gotos (or “threaded code”) on supported platforms. As a result, Python 3.11 executes the pyperformance regular expression benchmarks [https://pyperformance.readthedocs.io/benchmarks.html#regex-dna] up to 10% faster than Python 3.10. (Contributed by Brandt Bucher in gh-91404 [https://github.com/python/cpython/issues/91404].)

FAQ

How should I write my code to utilize these speedups?

Write Pythonic code that follows common best practices; you don’t have to change your code. The Faster CPython project optimizes for common code patterns we observe.

Will CPython 3.11 use more memory?

Maybe not; we don’t expect memory use to exceed 20% higher than 3.10. This is offset by memory optimizations for frame objects and object dictionaries as mentioned above.

I don’t see any speedups in my workload. Why?

Certain code won’t have noticeable benefits. If your code spends most of its time on I/O operations, or already does most of its computation in a C extension library like NumPy, there won’t be significant speedups. This project currently benefits pure-Python workloads the most.

Furthermore, the pyperformance figures are a geometric mean. Even within the pyperformance benchmarks, certain benchmarks have slowed down slightly, while others have sped up by nearly 2x!

Is there a JIT compiler?

No. We’re still exploring other optimizations.

About

Faster CPython explores optimizations for CPython. The main team is funded by Microsoft to work on this full-time. Pablo Galindo Salgado is also funded by Bloomberg LP to work on the project part-time. Finally, many contributors are volunteers from the community.

CPython bytecode changes

The bytecode now contains inline cache entries, which take the form of the newly-added CACHE instructions. Many opcodes expect to be followed by an exact number of caches, and instruct the interpreter to skip over them at runtime. Populated caches can look like arbitrary instructions, so great care should be taken when reading or modifying raw, adaptive bytecode containing quickened data.

New opcodes

ASYNC_GEN_WRAP, RETURN_GENERATOR and SEND, used in generators and co-routines.

COPY_FREE_VARS, which avoids needing special caller-side code for closures.

JUMP_BACKWARD_NO_INTERRUPT, for use in certain loops where handling interrupts is undesirable.

MAKE_CELL, to create 셀 객체.

CHECK_EG_MATCH and PREP_RERAISE_STAR, to handle the new exception groups and except* added in PEP 654 [https://peps.python.org/pep-0654/].

PUSH_EXC_INFO, for use in exception handlers.

RESUME, a no-op, for internal tracing, debugging and optimization checks.

Replaced opcodes

Replaced Opcode(s)

New Opcode(s)

Notes

BINARY_*

INPLACE_*

BINARY_OP

Replaced all numeric binary/in-place opcodes with a single opcode

CALL_FUNCTION

CALL_FUNCTION_KW

CALL_METHOD

CALL

KW_NAMES

PRECALL

PUSH_NULL

Decouples argument shifting for methods from handling of keyword arguments; allows better specialization of calls

DUP_TOP

DUP_TOP_TWO

ROT_TWO

ROT_THREE

ROT_FOUR

ROT_N

COPY

SWAP

Stack manipulation instructions

JUMP_IF_NOT_EXC_MATCH

CHECK_EXC_MATCH

Now performs check but doesn’t jump

JUMP_ABSOLUTE

POP_JUMP_IF_FALSE

POP_JUMP_IF_TRUE

JUMP_BACKWARD

POP_JUMP_BACKWARD_IF_*

POP_JUMP_FORWARD_IF_*

See [3]; TRUE, FALSE, NONE and NOT_NONE variants for each direction

SETUP_WITH

SETUP_ASYNC_WITH

BEFORE_WITH

with block setup

[3]

All jump opcodes are now relative, including the existing JUMP_IF_TRUE_OR_POP and JUMP_IF_FALSE_OR_POP. The argument is now an offset from the current instruction rather than an absolute location.

Changed/removed opcodes

Changed MATCH_CLASS and MATCH_KEYS to no longer push an additional boolean value to indicate success/failure. Instead, None is pushed on failure in place of the tuple of extracted values.

Changed opcodes that work with exceptions to reflect them now being represented as one item on the stack instead of three (see gh-89874 [https://github.com/python/cpython/issues/89874]).

Removed COPY_DICT_WITHOUT_KEYS, GEN_START, POP_BLOCK, SETUP_FINALLY and YIELD_FROM.

Deprecated

This section lists Python APIs that have been deprecated in Python 3.11.

Deprecated C APIs are listed separately.

Language/Builtins

Chaining classmethod descriptors (introduced in bpo-19072 [https://bugs.python.org/issue?@action=redirect&bpo=19072]) is now deprecated. It can no longer be used to wrap other descriptors such as property. The core design of this feature was flawed and caused a number of downstream problems. To “pass-through” a classmethod, consider using the __wrapped__ attribute that was added in Python 3.10. (Contributed by Raymond Hettinger in gh-89519 [https://github.com/python/cpython/issues/89519].)

Octal escapes in string and bytes literals with values larger than 0o377 (255 in decimal) now produce a DeprecationWarning. In a future Python version, they will raise a SyntaxWarning and eventually a SyntaxError. (Contributed by Serhiy Storchaka in gh-81548 [https://github.com/python/cpython/issues/81548].)

The delegation of int() to __trunc__() is now deprecated. Calling int(a) when type(a) implements __trunc__() but not __int__() or __index__() now raises a DeprecationWarning. (Contributed by Zackery Spytz in bpo-44977 [https://bugs.python.org/issue?@action=redirect&bpo=44977].)

Modules

PEP 594 [https://peps.python.org/pep-0594/] led to the deprecations of the following modules slated for removal in Python 3.13:

aifc

chunk

msilib

pipes

telnetlib

audioop

crypt

nis

sndhdr

uu

cgi

imghdr

nntplib

spwd

xdrlib

cgitb

mailcap

ossaudiodev

sunau

(Contributed by Brett Cannon in bpo-47061 [https://bugs.python.org/issue?@action=redirect&bpo=47061] and Victor Stinner in gh-68966 [https://github.com/python/cpython/issues/68966].)

The asynchat, asyncore and smtpd modules have been deprecated since at least Python 3.6. Their documentation and deprecation warnings have now been updated to note they will be removed in Python 3.12. (Contributed by Hugo van Kemenade in bpo-47022 [https://bugs.python.org/issue?@action=redirect&bpo=47022].)

The lib2to3 package and 2to3 tool are now deprecated and may not be able to parse Python 3.10 or newer. See PEP 617 [https://peps.python.org/pep-0617/], introducing the new PEG parser, for details. (Contributed by Victor Stinner in bpo-40360 [https://bugs.python.org/issue?@action=redirect&bpo=40360].)

Undocumented modules sre_compile, sre_constants and sre_parse are now deprecated. (Contributed by Serhiy Storchaka in bpo-47152 [https://bugs.python.org/issue?@action=redirect&bpo=47152].)

Standard Library

The following have been deprecated in configparser since Python 3.2. Their deprecation warnings have now been updated to note they will be removed in Python 3.12:

the configparser.SafeConfigParser class

the configparser.ParsingError.filename property

the configparser.RawConfigParser.readfp() method

(Contributed by Hugo van Kemenade in bpo-45173 [https://bugs.python.org/issue?@action=redirect&bpo=45173].)

configparser.LegacyInterpolation has been deprecated in the docstring since Python 3.2, and is not listed in the configparser documentation. It now emits a DeprecationWarning and will be removed in Python 3.13. Use configparser.BasicInterpolation or configparser.ExtendedInterpolation instead. (Contributed by Hugo van Kemenade in bpo-46607 [https://bugs.python.org/issue?@action=redirect&bpo=46607].)

The older set of importlib.resources functions were deprecated in favor of the replacements added in Python 3.9 and will be removed in a future Python version, due to not supporting resources located within package subdirectories:

importlib.resources.contents()

importlib.resources.is_resource()

importlib.resources.open_binary()

importlib.resources.open_text()

importlib.resources.read_binary()

importlib.resources.read_text()

importlib.resources.path()

The locale.getdefaultlocale() function is deprecated and will be removed in Python 3.15. Use locale.setlocale(), locale.getpreferredencoding(False) and locale.getlocale() functions instead. (Contributed by Victor Stinner in gh-90817 [https://github.com/python/cpython/issues/90817].)

The locale.resetlocale() function is deprecated and will be removed in Python 3.13. Use locale.setlocale(locale.LC_ALL, "") instead. (Contributed by Victor Stinner in gh-90817 [https://github.com/python/cpython/issues/90817].)

Stricter rules will now be applied for numerical group references and group names in regular expressions. Only sequences of ASCII digits will now be accepted as a numerical reference, and the group name in bytes patterns and replacement strings can only contain ASCII letters, digits and underscores. For now, a deprecation warning is raised for syntax violating these rules. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

In the re module, the re.template() function and the corresponding re.TEMPLATE and re.T flags are deprecated, as they were undocumented and lacked an obvious purpose. They will be removed in Python 3.13. (Contributed by Serhiy Storchaka and Miro Hrončok in gh-92728 [https://github.com/python/cpython/issues/92728].)

turtle.settiltangle() has been deprecated since Python 3.1; it now emits a deprecation warning and will be removed in Python 3.13. Use turtle.tiltangle() instead (it was earlier incorrectly marked as deprecated, and its docstring is now corrected). (Contributed by Hugo van Kemenade in bpo-45837 [https://bugs.python.org/issue?@action=redirect&bpo=45837].)

typing.Text, which exists solely to provide compatibility support between Python 2 and Python 3 code, is now deprecated. Its removal is currently unplanned, but users are encouraged to use str instead wherever possible. (Contributed by Alex Waygood in gh-92332 [https://github.com/python/cpython/issues/92332].)

The keyword argument syntax for constructing typing.TypedDict types is now deprecated. Support will be removed in Python 3.13. (Contributed by Jingchen Ye in gh-90224 [https://github.com/python/cpython/issues/90224].)

webbrowser.MacOSX is deprecated and will be removed in Python 3.13. It is untested, undocumented, and not used by webbrowser itself. (Contributed by Donghee Na in bpo-42255 [https://bugs.python.org/issue?@action=redirect&bpo=42255].)

The behavior of returning a value from a TestCase and IsolatedAsyncioTestCase test methods (other than the default None value) is now deprecated.

Deprecated the following not-formally-documented unittest functions, scheduled for removal in Python 3.13:

unittest.findTestCases()

unittest.makeSuite()

unittest.getTestCaseNames()

Use TestLoader methods instead:

unittest.TestLoader.loadTestsFromModule()

unittest.TestLoader.loadTestsFromTestCase()

unittest.TestLoader.getTestCaseNames()

(Contributed by Erlend E. Aasland in bpo-5846 [https://bugs.python.org/issue?@action=redirect&bpo=5846].)

unittest.TestProgram.usageExit() is marked deprecated, to be removed in 3.13. (Contributed by Carlos Damázio in gh-67048 [https://github.com/python/cpython/issues/67048].)

Pending Removal in Python 3.12

The following Python APIs have been deprecated in earlier Python releases, and will be removed in Python 3.12.

C APIs pending removal are listed separately.

The asynchat module

The asyncore module

The entire distutils package

The imp module

The typing.io namespace

The typing.re namespace

cgi.log()

importlib.find_loader()

importlib.abc.Loader.module_repr()

importlib.abc.MetaPathFinder.find_module()

importlib.abc.PathEntryFinder.find_loader()

importlib.abc.PathEntryFinder.find_module()

importlib.machinery.BuiltinImporter.find_module()

importlib.machinery.BuiltinLoader.module_repr()

importlib.machinery.FileFinder.find_loader()

importlib.machinery.FileFinder.find_module()

importlib.machinery.FrozenImporter.find_module()

importlib.machinery.FrozenLoader.module_repr()

importlib.machinery.PathFinder.find_module()

importlib.machinery.WindowsRegistryFinder.find_module()

importlib.util.module_for_loader()

importlib.util.set_loader_wrapper()

importlib.util.set_package_wrapper()

pkgutil.ImpImporter

pkgutil.ImpLoader

pathlib.Path.link_to()

sqlite3.enable_shared_cache()

sqlite3.OptimizedUnicode()

PYTHONTHREADDEBUG environment variable

The following deprecated aliases in unittest:

Deprecated alias

Method Name

Deprecated in

failUnless

assertTrue()

3.1

failIf

assertFalse()

3.1

failUnlessEqual

assertEqual()

3.1

failIfEqual

assertNotEqual()

3.1

failUnlessAlmostEqual

assertAlmostEqual()

3.1

failIfAlmostEqual

assertNotAlmostEqual()

3.1

failUnlessRaises

assertRaises()

3.1

assert_

assertTrue()

3.2

assertEquals

assertEqual()

3.2

assertNotEquals

assertNotEqual()

3.2

assertAlmostEquals

assertAlmostEqual()

3.2

assertNotAlmostEquals

assertNotAlmostEqual()

3.2

assertRegexpMatches

assertRegex()

3.2

assertRaisesRegexp

assertRaisesRegex()

3.2

assertNotRegexpMatches

assertNotRegex()

3.5

Removed

This section lists Python APIs that have been removed in Python 3.11.

Removed C APIs are listed separately.

Removed the @asyncio.coroutine() decorator enabling legacy generator-based coroutines to be compatible with async / await code. The function has been deprecated since Python 3.8 and the removal was initially scheduled for Python 3.10. Use async def instead. (Contributed by Illia Volochii in bpo-43216 [https://bugs.python.org/issue?@action=redirect&bpo=43216].)

Removed asyncio.coroutines.CoroWrapper used for wrapping legacy generator-based coroutine objects in the debug mode. (Contributed by Illia Volochii in bpo-43216 [https://bugs.python.org/issue?@action=redirect&bpo=43216].)

Due to significant security concerns, the reuse_address parameter of asyncio.loop.create_datagram_endpoint(), disabled in Python 3.9, is now entirely removed. This is because of the behavior of the socket option SO_REUSEADDR in UDP. (Contributed by Hugo van Kemenade in bpo-45129 [https://bugs.python.org/issue?@action=redirect&bpo=45129].)

Removed the binhex module, deprecated in Python 3.9. Also removed the related, similarly-deprecated binascii functions:

binascii.a2b_hqx()

binascii.b2a_hqx()

binascii.rlecode_hqx()

binascii.rldecode_hqx()

The binascii.crc_hqx() function remains available.

(Contributed by Victor Stinner in bpo-45085 [https://bugs.python.org/issue?@action=redirect&bpo=45085].)

Removed the distutils bdist_msi command deprecated in Python 3.9. Use bdist_wheel (wheel packages) instead. (Contributed by Hugo van Kemenade in bpo-45124 [https://bugs.python.org/issue?@action=redirect&bpo=45124].)

Removed the __getitem__() methods of xml.dom.pulldom.DOMEventStream, wsgiref.util.FileWrapper and fileinput.FileInput, deprecated since Python 3.9. (Contributed by Hugo van Kemenade in bpo-45132 [https://bugs.python.org/issue?@action=redirect&bpo=45132].)

Removed the deprecated gettext functions lgettext(), ldgettext(), lngettext() and ldngettext(). Also removed the bind_textdomain_codeset() function, the NullTranslations.output_charset() and NullTranslations.set_output_charset() methods, and the codeset parameter of translation() and install(), since they are only used for the l*gettext() functions. (Contributed by Donghee Na and Serhiy Storchaka in bpo-44235 [https://bugs.python.org/issue?@action=redirect&bpo=44235].)

Removed from the inspect module:

The getargspec() function, deprecated since Python 3.0; use inspect.signature() or inspect.getfullargspec() instead.

The formatargspec() function, deprecated since Python 3.5; use the inspect.signature() function or the inspect.Signature object directly.

The undocumented Signature.from_builtin() and Signature.from_function() methods, deprecated since Python 3.5; use the Signature.from_callable() method instead.

(Contributed by Hugo van Kemenade in bpo-45320 [https://bugs.python.org/issue?@action=redirect&bpo=45320].)

Removed the __class_getitem__() method from pathlib.PurePath, because it was not used and added by mistake in previous versions. (Contributed by Nikita Sobolev in bpo-46483 [https://bugs.python.org/issue?@action=redirect&bpo=46483].)

Removed the MailmanProxy class in the smtpd module, as it is unusable without the external mailman package. (Contributed by Donghee Na in bpo-35800 [https://bugs.python.org/issue?@action=redirect&bpo=35800].)

Removed the deprecated split() method of _tkinter.TkappType. (Contributed by Erlend E. Aasland in bpo-38371 [https://bugs.python.org/issue?@action=redirect&bpo=38371].)

Removed namespace package support from unittest discovery. It was introduced in Python 3.4 but has been broken since Python 3.7. (Contributed by Inada Naoki in bpo-23882 [https://bugs.python.org/issue?@action=redirect&bpo=23882].)

Removed the undocumented private float.__set_format__() method, previously known as float.__setformat__() in Python 3.7. Its docstring said: “You probably don’t want to use this function. It exists mainly to be used in Python’s test suite.” (Contributed by Victor Stinner in bpo-46852 [https://bugs.python.org/issue?@action=redirect&bpo=46852].)

The --experimental-isolated-subinterpreters configure flag (and corresponding EXPERIMENTAL_ISOLATED_SUBINTERPRETERS macro) have been removed.

Pynche [https://pypi.org/project/Pynche/] — The Pythonically Natural Color and Hue Editor — has been moved out of Tools/scripts and is being developed independently [https://gitlab.com/warsaw/pynche/-/tree/main] from the Python source tree.

Porting to Python 3.11

This section lists previously described changes and other bugfixes in the Python API that may require changes to your Python code.

Porting notes for the C API are listed separately.

open(), io.open(), codecs.open() and fileinput.FileInput no longer accept 'U' (“universal newline”) in the file mode. In Python 3, “universal newline” mode is used by default whenever a file is opened in text mode, and the 'U' flag has been deprecated since Python 3.3. The newline parameter to these functions controls how universal newlines work. (Contributed by Victor Stinner in bpo-37330 [https://bugs.python.org/issue?@action=redirect&bpo=37330].)

ast.AST node positions are now validated when provided to compile() and other related functions. If invalid positions are detected, a ValueError will be raised. (Contributed by Pablo Galindo in gh-93351 [https://github.com/python/cpython/issues/93351])

Prohibited passing non-concurrent.futures.ThreadPoolExecutor executors to asyncio.loop.set_default_executor() following a deprecation in Python 3.8. (Contributed by Illia Volochii in bpo-43234 [https://bugs.python.org/issue?@action=redirect&bpo=43234].)

calendar: The calendar.LocaleTextCalendar and calendar.LocaleHTMLCalendar classes now use locale.getlocale(), instead of using locale.getdefaultlocale(), if no locale is specified. (Contributed by Victor Stinner in bpo-46659 [https://bugs.python.org/issue?@action=redirect&bpo=46659].)

The pdb module now reads the .pdbrc configuration file with the 'UTF-8' encoding. (Contributed by Srinivas Reddy Thatiparthy (శ్రీనివాస్ రెడ్డి తాటిపర్తి) in bpo-41137 [https://bugs.python.org/issue?@action=redirect&bpo=41137].)

The population parameter of random.sample() must be a sequence, and automatic conversion of sets to lists is no longer supported. Also, if the sample size is larger than the population size, a ValueError is raised. (Contributed by Raymond Hettinger in bpo-40465 [https://bugs.python.org/issue?@action=redirect&bpo=40465].)

The random optional parameter of random.shuffle() was removed. It was previously an arbitrary random function to use for the shuffle; now, random.random() (its previous default) will always be used.

In re 정규식 문법, global inline flags (e.g. (?i)) can now only be used at the start of regular expressions. Using them elsewhere has been deprecated since Python 3.6. (Contributed by Serhiy Storchaka in bpo-47066 [https://bugs.python.org/issue?@action=redirect&bpo=47066].)

In the re module, several long-standing bugs where fixed that, in rare cases, could cause capture groups to get the wrong result. Therefore, this could change the captured output in these cases. (Contributed by Ma Lin in bpo-35859 [https://bugs.python.org/issue?@action=redirect&bpo=35859].)

Build Changes

CPython now has PEP 11 [https://peps.python.org/pep-0011/] Tier 3 support [https://peps.python.org/pep-0011/#tier-3] for cross compiling to the WebAssembly [https://webassembly.org/] platforms Emscripten [https://emscripten.org/] (wasm32-unknown-emscripten, i.e. Python in the browser) and WebAssembly System Interface (WASI) [https://wasi.dev/] (wasm32-unknown-wasi). The effort is inspired by previous work like Pyodide [https://pyodide.org/]. These platforms provide a limited subset of POSIX APIs; Python standard libraries features and modules related to networking, processes, threading, signals, mmap, and users/groups are not available or don’t work. (Emscripten contributed by Christian Heimes and Ethan Smith in gh-84461 [https://github.com/python/cpython/issues/84461] and WASI contributed by Christian Heimes in gh-90473 [https://github.com/python/cpython/issues/90473]; platforms promoted in gh-95085 [https://github.com/python/cpython/issues/95085])

Building CPython now requires:

A C11 [https://en.cppreference.com/w/c/11] compiler and standard library. Optional C11 features [https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features] are not required. (Contributed by Victor Stinner in bpo-46656 [https://bugs.python.org/issue?@action=redirect&bpo=46656], bpo-45440 [https://bugs.python.org/issue?@action=redirect&bpo=45440] and bpo-46640 [https://bugs.python.org/issue?@action=redirect&bpo=46640].)

Support for IEEE 754 [https://en.wikipedia.org/wiki/IEEE_754] floating-point numbers. (Contributed by Victor Stinner in bpo-46917 [https://bugs.python.org/issue?@action=redirect&bpo=46917].)

The Py_NO_NAN macro has been removed. Since CPython now requires IEEE 754 floats, NaN values are always available. (Contributed by Victor Stinner in bpo-46656 [https://bugs.python.org/issue?@action=redirect&bpo=46656].)

The tkinter package now requires Tcl/Tk [https://www.tcl.tk] version 8.5.12 or newer. (Contributed by Serhiy Storchaka in bpo-46996 [https://bugs.python.org/issue?@action=redirect&bpo=46996].)

Build dependencies, compiler flags, and linker flags for most stdlib extension modules are now detected by configure. libffi, libnsl, libsqlite3, zlib, bzip2, liblzma, libcrypt, Tcl/Tk, and uuid flags are detected by pkg-config [https://www.freedesktop.org/wiki/Software/pkg-config/] (when available). tkinter now requires a pkg-config command to detect development settings for Tcl/Tk [https://www.tcl.tk] headers and libraries. (Contributed by Christian Heimes and Erlend Egeberg Aasland in bpo-45847 [https://bugs.python.org/issue?@action=redirect&bpo=45847], bpo-45747 [https://bugs.python.org/issue?@action=redirect&bpo=45747], and bpo-45763 [https://bugs.python.org/issue?@action=redirect&bpo=45763].)

libpython is no longer linked against libcrypt. (Contributed by Mike Gilbert in bpo-45433 [https://bugs.python.org/issue?@action=redirect&bpo=45433].)

CPython can now be built with the ThinLTO [https://clang.llvm.org/docs/ThinLTO.html] option via passing thin to --with-lto, i.e. --with-lto=thin. (Contributed by Donghee Na and Brett Holman in bpo-44340 [https://bugs.python.org/issue?@action=redirect&bpo=44340].)

Freelists for object structs can now be disabled. A new configure option --without-freelists can be used to disable all freelists except empty tuple singleton. (Contributed by Christian Heimes in bpo-45522 [https://bugs.python.org/issue?@action=redirect&bpo=45522].)

Modules/Setup and Modules/makesetup have been improved and tied up. Extension modules can now be built through makesetup. All except some test modules can be linked statically into a main binary or library. (Contributed by Brett Cannon and Christian Heimes in bpo-45548 [https://bugs.python.org/issue?@action=redirect&bpo=45548], bpo-45570 [https://bugs.python.org/issue?@action=redirect&bpo=45570], bpo-45571 [https://bugs.python.org/issue?@action=redirect&bpo=45571], and bpo-43974 [https://bugs.python.org/issue?@action=redirect&bpo=43974].)

참고

Use the environment variables TCLTK_CFLAGS and TCLTK_LIBS to manually specify the location of Tcl/Tk headers and libraries. The configure options --with-tcltk-includes and --with-tcltk-libs have been removed.

On RHEL 7 and CentOS 7 the development packages do not provide tcl.pc and tk.pc; use TCLTK_LIBS="-ltk8.5 -ltkstub8.5 -ltcl8.5". The directory Misc/rhel7 contains .pc files and instructions on how to build Python with RHEL 7’s and CentOS 7’s Tcl/Tk and OpenSSL.

CPython will now use 30-bit digits by default for the Python int implementation. Previously, the default was to use 30-bit digits on platforms with SIZEOF_VOID_P >= 8, and 15-bit digits otherwise. It’s still possible to explicitly request use of 15-bit digits via either the --enable-big-digits option to the configure script or (for Windows) the PYLONG_BITS_IN_DIGIT variable in PC/pyconfig.h, but this option may be removed at some point in the future. (Contributed by Mark Dickinson in bpo-45569 [https://bugs.python.org/issue?@action=redirect&bpo=45569].)

C API Changes

New Features

Add a new PyType_GetName() function to get type’s short name. (Contributed by Hai Shi in bpo-42035 [https://bugs.python.org/issue?@action=redirect&bpo=42035].)

Add a new PyType_GetQualName() function to get type’s qualified name. (Contributed by Hai Shi in bpo-42035 [https://bugs.python.org/issue?@action=redirect&bpo=42035].)

Add new PyThreadState_EnterTracing() and PyThreadState_LeaveTracing() functions to the limited C API to suspend and resume tracing and profiling. (Contributed by Victor Stinner in bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760].)

Added the Py_Version constant which bears the same value as PY_VERSION_HEX. (Contributed by Gabriele N. Tornetta in bpo-43931 [https://bugs.python.org/issue?@action=redirect&bpo=43931].)

Py_buffer and APIs are now part of the limited API and the stable ABI:

PyObject_CheckBuffer()

PyObject_GetBuffer()

PyBuffer_GetPointer()

PyBuffer_SizeFromFormat()

PyBuffer_ToContiguous()

PyBuffer_FromContiguous()

PyObject_CopyData()

PyBuffer_IsContiguous()

PyBuffer_FillContiguousStrides()

PyBuffer_FillInfo()

PyBuffer_Release()

PyMemoryView_FromBuffer()

bf_getbuffer and bf_releasebuffer type slots

(Contributed by Christian Heimes in bpo-45459 [https://bugs.python.org/issue?@action=redirect&bpo=45459].)

Added the PyType_GetModuleByDef() function, used to get the module in which a method was defined, in cases where this information is not available directly (via PyCMethod). (Contributed by Petr Viktorin in bpo-46613 [https://bugs.python.org/issue?@action=redirect&bpo=46613].)

Add new functions to pack and unpack C double (serialize and deserialize): PyFloat_Pack2(), PyFloat_Pack4(), PyFloat_Pack8(), PyFloat_Unpack2(), PyFloat_Unpack4() and PyFloat_Unpack8(). (Contributed by Victor Stinner in bpo-46906 [https://bugs.python.org/issue?@action=redirect&bpo=46906].)

Add new functions to get frame object attributes: PyFrame_GetBuiltins(), PyFrame_GetGenerator(), PyFrame_GetGlobals(), PyFrame_GetLasti().

Added two new functions to get and set the active exception instance: PyErr_GetHandledException() and PyErr_SetHandledException(). These are alternatives to PyErr_SetExcInfo() and PyErr_GetExcInfo() which work with the legacy 3-tuple representation of exceptions. (Contributed by Irit Katriel in bpo-46343 [https://bugs.python.org/issue?@action=redirect&bpo=46343].)

Added the PyConfig.safe_path member. (Contributed by Victor Stinner in gh-57684 [https://github.com/python/cpython/issues/57684].)

Porting to Python 3.11

Some macros have been converted to static inline functions to avoid macro pitfalls [https://gcc.gnu.org/onlinedocs/cpp/Macro-Pitfalls.html]. The change should be mostly transparent to users, as the replacement functions will cast their arguments to the expected types to avoid compiler warnings due to static type checks. However, when the limited C API is set to >=3.11, these casts are not done, and callers will need to cast arguments to their expected types. See PEP 670 [https://peps.python.org/pep-0670/] for more details. (Contributed by Victor Stinner and Erlend E. Aasland in gh-89653 [https://github.com/python/cpython/issues/89653].)

PyErr_SetExcInfo() no longer uses the type and traceback arguments, the interpreter now derives those values from the exception instance (the value argument). The function still steals references of all three arguments. (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

PyErr_GetExcInfo() now derives the type and traceback fields of the result from the exception instance (the value field). (Contributed by Irit Katriel in bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711].)

_frozen has a new is_package field to indicate whether or not the frozen module is a package. Previously, a negative value in the size field was the indicator. Now only non-negative values be used for size. (Contributed by Kumar Aditya in bpo-46608 [https://bugs.python.org/issue?@action=redirect&bpo=46608].)

_PyFrameEvalFunction() now takes _PyInterpreterFrame* as its second parameter, instead of PyFrameObject*. See PEP 523 [https://peps.python.org/pep-0523/] for more details of how to use this function pointer type.

PyCode_New() and PyCode_NewWithPosOnlyArgs() now take an additional exception_table argument. Using these functions should be avoided, if at all possible. To get a custom code object: create a code object using the compiler, then get a modified version with the replace method.

PyCodeObject no longer has the co_code, co_varnames, co_cellvars and co_freevars fields. Instead, use PyCode_GetCode(), PyCode_GetVarnames(), PyCode_GetCellvars() and PyCode_GetFreevars() respectively to access them via the C API. (Contributed by Brandt Bucher in bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841] and Ken Jin in gh-92154 [https://github.com/python/cpython/issues/92154] and gh-94936 [https://github.com/python/cpython/issues/94936].)

The old trashcan macros (Py_TRASHCAN_SAFE_BEGIN/Py_TRASHCAN_SAFE_END) are now deprecated. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END.

A tp_dealloc function that has the old macros, such as:

static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_SAFE_BEGIN(p);
    ...
    Py_TRASHCAN_SAFE_END
}

should migrate to the new macros as follows:

static void
mytype_dealloc(mytype *p)
{
    PyObject_GC_UnTrack(p);
    Py_TRASHCAN_BEGIN(p, mytype_dealloc)
    ...
    Py_TRASHCAN_END
}

Note that Py_TRASHCAN_BEGIN has a second argument which should be the deallocation function it is in.

To support older Python versions in the same codebase, you can define the following macros and use them throughout the code (credit: these were copied from the mypy codebase):

#if PY_VERSION_HEX >= 0x03080000
#  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_BEGIN(op, dealloc)
#  define CPy_TRASHCAN_END(op) Py_TRASHCAN_END
#else
#  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_SAFE_BEGIN(op)
#  define CPy_TRASHCAN_END(op) Py_TRASHCAN_SAFE_END(op)
#endif

The PyType_Ready() function now raises an error if a type is defined with the Py_TPFLAGS_HAVE_GC flag set but has no traverse function (PyTypeObject.tp_traverse). (Contributed by Victor Stinner in bpo-44263 [https://bugs.python.org/issue?@action=redirect&bpo=44263].)

Heap types with the Py_TPFLAGS_IMMUTABLETYPE flag can now inherit the PEP 590 [https://peps.python.org/pep-0590/] vectorcall protocol. Previously, this was only possible for static types. (Contributed by Erlend E. Aasland in bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908])

Since Py_TYPE() is changed to a inline static function, Py_TYPE(obj) = new_type must be replaced with Py_SET_TYPE(obj, new_type): see the Py_SET_TYPE() function (available since Python 3.9). For backward compatibility, this macro can be used:

#if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_TYPE)
static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type)
{ ob->ob_type = type; }
#define Py_SET_TYPE(ob, type) _Py_SET_TYPE((PyObject*)(ob), type)
#endif

(Contributed by Victor Stinner in bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573].)

Since Py_SIZE() is changed to a inline static function, Py_SIZE(obj) = new_size must be replaced with Py_SET_SIZE(obj, new_size): see the Py_SET_SIZE() function (available since Python 3.9). For backward compatibility, this macro can be used:

#if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_SIZE)
static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size)
{ ob->ob_size = size; }
#define Py_SET_SIZE(ob, size) _Py_SET_SIZE((PyVarObject*)(ob), size)
#endif

(Contributed by Victor Stinner in bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573].)

<Python.h> no longer includes the header files <stdlib.h>, <stdio.h>, <errno.h> and <string.h> when the Py_LIMITED_API macro is set to 0x030b0000 (Python 3.11) or higher. C extensions should explicitly include the header files after #include <Python.h>. (Contributed by Victor Stinner in bpo-45434 [https://bugs.python.org/issue?@action=redirect&bpo=45434].)

The non-limited API files cellobject.h, classobject.h, code.h, context.h, funcobject.h, genobject.h and longintrepr.h have been moved to the Include/cpython directory. Moreover, the eval.h header file was removed. These files must not be included directly, as they are already included in Python.h: Include Files. If they have been included directly, consider including Python.h instead. (Contributed by Victor Stinner in bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134].)

The PyUnicode_CHECK_INTERNED() macro has been excluded from the limited C API. It was never usable there, because it used internal structures which are not available in the limited C API. (Contributed by Victor Stinner in bpo-46007 [https://bugs.python.org/issue?@action=redirect&bpo=46007].)

The following frame functions and type are now directly available with #include <Python.h>, it’s no longer needed to add #include <frameobject.h>:

PyFrame_Check()

PyFrame_GetBack()

PyFrame_GetBuiltins()

PyFrame_GetGenerator()

PyFrame_GetGlobals()

PyFrame_GetLasti()

PyFrame_GetLocals()

PyFrame_Type

(Contributed by Victor Stinner in gh-93937 [https://github.com/python/cpython/issues/93937].)

The PyFrameObject structure members have been removed from the public C API.

While the documentation notes that the PyFrameObject fields are subject to change at any time, they have been stable for a long time and were used in several popular extensions.

In Python 3.11, the frame struct was reorganized to allow performance optimizations. Some fields were removed entirely, as they were details of the old implementation.

PyFrameObject fields:

f_back: use PyFrame_GetBack().

f_blockstack: removed.

f_builtins: use PyFrame_GetBuiltins().

f_code: use PyFrame_GetCode().

f_gen: use PyFrame_GetGenerator().

f_globals: use PyFrame_GetGlobals().

f_iblock: removed.

f_lasti: use PyFrame_GetLasti(). Code using f_lasti with PyCode_Addr2Line() should use PyFrame_GetLineNumber() instead; it may be faster.

f_lineno: use PyFrame_GetLineNumber()

f_locals: use PyFrame_GetLocals().

f_stackdepth: removed.

f_state: no public API (renamed to f_frame.f_state).

f_trace: no public API.

f_trace_lines: use PyObject_GetAttrString((PyObject*)frame, "f_trace_lines").

f_trace_opcodes: use PyObject_GetAttrString((PyObject*)frame, "f_trace_opcodes").

f_localsplus: no public API (renamed to f_frame.localsplus).

f_valuestack: removed.

The Python frame object is now created lazily. A side effect is that the f_back member must not be accessed directly, since its value is now also computed lazily. The PyFrame_GetBack() function must be called instead.

Debuggers that accessed the f_locals directly must call PyFrame_GetLocals() instead. They no longer need to call PyFrame_FastToLocalsWithError() or PyFrame_LocalsToFast(), in fact they should not call those functions. The necessary updating of the frame is now managed by the virtual machine.

Code defining PyFrame_GetCode() on Python 3.8 and older:

#if PY_VERSION_HEX < 0x030900B1
static inline PyCodeObject* PyFrame_GetCode(PyFrameObject *frame)
{
    Py_INCREF(frame->f_code);
    return frame->f_code;
}
#endif

Code defining PyFrame_GetBack() on Python 3.8 and older:

#if PY_VERSION_HEX < 0x030900B1
static inline PyFrameObject* PyFrame_GetBack(PyFrameObject *frame)
{
    Py_XINCREF(frame->f_back);
    return frame->f_back;
}
#endif

Or use the pythoncapi_compat project [https://github.com/python/pythoncapi-compat] to get these two functions on older Python versions.

Changes of the PyThreadState structure members:

frame: removed, use PyThreadState_GetFrame() (function added to Python 3.9 by bpo-40429 [https://bugs.python.org/issue?@action=redirect&bpo=40429]). Warning: the function returns a strong reference, need to call Py_XDECREF().

tracing: changed, use PyThreadState_EnterTracing() and PyThreadState_LeaveTracing() (functions added to Python 3.11 by bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760]).

recursion_depth: removed, use (tstate->recursion_limit - tstate->recursion_remaining) instead.

stackcheck_counter: removed.

Code defining PyThreadState_GetFrame() on Python 3.8 and older:

#if PY_VERSION_HEX < 0x030900B1
static inline PyFrameObject* PyThreadState_GetFrame(PyThreadState *tstate)
{
    Py_XINCREF(tstate->frame);
    return tstate->frame;
}
#endif

Code defining PyThreadState_EnterTracing() and PyThreadState_LeaveTracing() on Python 3.10 and older:

#if PY_VERSION_HEX < 0x030B00A2
static inline void PyThreadState_EnterTracing(PyThreadState *tstate)
{
    tstate->tracing++;
#if PY_VERSION_HEX >= 0x030A00A1
    tstate->cframe->use_tracing = 0;
#else
    tstate->use_tracing = 0;
#endif
}

static inline void PyThreadState_LeaveTracing(PyThreadState *tstate)
{
    int use_tracing = (tstate->c_tracefunc != NULL || tstate->c_profilefunc != NULL);
    tstate->tracing--;
#if PY_VERSION_HEX >= 0x030A00A1
    tstate->cframe->use_tracing = use_tracing;
#else
    tstate->use_tracing = use_tracing;
#endif
}
#endif

Or use the pythoncapi-compat project [https://github.com/python/pythoncapi-compat] to get these functions on old Python functions.

Distributors are encouraged to build Python with the optimized Blake2 library libb2 [https://www.blake2.net/].

The PyConfig.module_search_paths_set field must now be set to 1 for initialization to use PyConfig.module_search_paths to initialize sys.path. Otherwise, initialization will recalculate the path and replace any values added to module_search_paths.

PyConfig_Read() no longer calculates the initial search path, and will not fill any values into PyConfig.module_search_paths. To calculate default paths and then modify them, finish initialization and use PySys_GetObject() to retrieve sys.path as a Python list object and modify it directly.

Deprecated

Deprecate the following functions to configure the Python initialization:

PySys_AddWarnOptionUnicode()

PySys_AddWarnOption()

PySys_AddXOption()

PySys_HasWarnOptions()

PySys_SetArgvEx()

PySys_SetArgv()

PySys_SetPath()

Py_SetPath()

Py_SetProgramName()

Py_SetPythonHome()

Py_SetStandardStreamEncoding()

_Py_SetProgramFullPath()

Use the new PyConfig API of the Python Initialization Configuration instead (PEP 587 [https://peps.python.org/pep-0587/]). (Contributed by Victor Stinner in gh-88279 [https://github.com/python/cpython/issues/88279].)

Deprecate the ob_shash member of the PyBytesObject. Use PyObject_Hash() instead. (Contributed by Inada Naoki in bpo-46864 [https://bugs.python.org/issue?@action=redirect&bpo=46864].)

Pending Removal in Python 3.12

The following C APIs have been deprecated in earlier Python releases, and will be removed in Python 3.12.

PyUnicode_AS_DATA()

PyUnicode_AS_UNICODE()

PyUnicode_AsUnicodeAndSize()

PyUnicode_AsUnicode()

PyUnicode_FromUnicode()

PyUnicode_GET_DATA_SIZE()

PyUnicode_GET_SIZE()

PyUnicode_GetSize()

PyUnicode_IS_COMPACT()

PyUnicode_IS_READY()

PyUnicode_READY()

PyUnicode_WSTR_LENGTH()

_PyUnicode_AsUnicode()

PyUnicode_WCHAR_KIND

PyUnicodeObject

PyUnicode_InternImmortal()

Removed

PyFrame_BlockSetup() and PyFrame_BlockPop() have been removed. (Contributed by Mark Shannon in bpo-40222 [https://bugs.python.org/issue?@action=redirect&bpo=40222].)

Remove the following math macros using the errno variable:

Py_ADJUST_ERANGE1()

Py_ADJUST_ERANGE2()

Py_OVERFLOWED()

Py_SET_ERANGE_IF_OVERFLOW()

Py_SET_ERRNO_ON_MATH_ERROR()

(Contributed by Victor Stinner in bpo-45412 [https://bugs.python.org/issue?@action=redirect&bpo=45412].)

Remove Py_UNICODE_COPY() and Py_UNICODE_FILL() macros, deprecated since Python 3.3. Use PyUnicode_CopyCharacters() or memcpy() (wchar_t* string), and PyUnicode_Fill() functions instead. (Contributed by Victor Stinner in bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123].)

Remove the pystrhex.h header file. It only contains private functions. C extensions should only include the main <Python.h> header file. (Contributed by Victor Stinner in bpo-45434 [https://bugs.python.org/issue?@action=redirect&bpo=45434].)

Remove the Py_FORCE_DOUBLE() macro. It was used by the Py_IS_INFINITY() macro. (Contributed by Victor Stinner in bpo-45440 [https://bugs.python.org/issue?@action=redirect&bpo=45440].)

The following items are no longer available when Py_LIMITED_API is defined:

PyMarshal_WriteLongToFile()

PyMarshal_WriteObjectToFile()

PyMarshal_ReadObjectFromString()

PyMarshal_WriteObjectToString()

the Py_MARSHAL_VERSION macro

These are not part of the limited API.

(Contributed by Victor Stinner in bpo-45474 [https://bugs.python.org/issue?@action=redirect&bpo=45474].)

Exclude PyWeakref_GET_OBJECT() from the limited C API. It never worked since the PyWeakReference structure is opaque in the limited C API. (Contributed by Victor Stinner in bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134].)

Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the public C API by mistake, it must only be used by Python internally. Use the PyTypeObject.tp_members member instead. (Contributed by Victor Stinner in bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170].)

Remove the HAVE_PY_SET_53BIT_PRECISION macro (moved to the internal C API). (Contributed by Victor Stinner in bpo-45412 [https://bugs.python.org/issue?@action=redirect&bpo=45412].)

Remove the Py_UNICODE encoder APIs, as they have been deprecated since Python 3.3, are little used and are inefficient relative to the recommended alternatives.

The removed functions are:

PyUnicode_Encode()

PyUnicode_EncodeASCII()

PyUnicode_EncodeLatin1()

PyUnicode_EncodeUTF7()

PyUnicode_EncodeUTF8()

PyUnicode_EncodeUTF16()

PyUnicode_EncodeUTF32()

PyUnicode_EncodeUnicodeEscape()

PyUnicode_EncodeRawUnicodeEscape()

PyUnicode_EncodeCharmap()

PyUnicode_TranslateCharmap()

PyUnicode_EncodeDecimal()

PyUnicode_TransformDecimalToASCII()

See PEP 624 [https://peps.python.org/pep-0624/] for details and migration guidance [https://peps.python.org/pep-0624/#alternative-apis]. (Contributed by Inada Naoki in bpo-44029 [https://bugs.python.org/issue?@action=redirect&bpo=44029].)

Notable changes in 3.11.4

tarfile

The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details. In Python 3.12, use without the filter argument will show a DeprecationWarning. In Python 3.14, the default will switch to 'data'. (Contributed by Petr Viktorin in PEP 706 [https://peps.python.org/pep-0706/].)

Notable changes in 3.11.5

OpenSSL

Windows builds and macOS installers from python.org now use OpenSSL 3.0.

What’s New In Python 3.10

Editor:

Pablo Galindo Salgado

This article explains the new features in Python 3.10, compared to 3.9. Python 3.10 was released on October 4, 2021. For full details, see the changelog.

Summary – Release highlights

New syntax features:

PEP 634 [https://peps.python.org/pep-0634/], Structural Pattern Matching: Specification

PEP 635 [https://peps.python.org/pep-0635/], Structural Pattern Matching: Motivation and Rationale

PEP 636 [https://peps.python.org/pep-0636/], Structural Pattern Matching: Tutorial

bpo-12782 [https://bugs.python.org/issue?@action=redirect&bpo=12782], Parenthesized context managers are now officially allowed.

New features in the standard library:

PEP 618 [https://peps.python.org/pep-0618/], Add Optional Length-Checking To zip.

Interpreter improvements:

PEP 626 [https://peps.python.org/pep-0626/], Precise line numbers for debugging and other tools.

New typing features:

PEP 604 [https://peps.python.org/pep-0604/], Allow writing union types as X | Y

PEP 612 [https://peps.python.org/pep-0612/], Parameter Specification Variables

PEP 613 [https://peps.python.org/pep-0613/], Explicit Type Aliases

PEP 647 [https://peps.python.org/pep-0647/], User-Defined Type Guards

Important deprecations, removals or restrictions:

PEP 644 [https://peps.python.org/pep-0644/], Require OpenSSL 1.1.1 or newer

PEP 632 [https://peps.python.org/pep-0632/], Deprecate distutils module.

PEP 623 [https://peps.python.org/pep-0623/], Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.

PEP 624 [https://peps.python.org/pep-0624/], Remove Py_UNICODE encoder APIs

PEP 597 [https://peps.python.org/pep-0597/], Add optional EncodingWarning

New Features

Parenthesized context managers

Using enclosing parentheses for continuation across multiple lines in context managers is now supported. This allows formatting a long collection of context managers in multiple lines in a similar way as it was previously possible with import statements. For instance, all these examples are now valid:

with (CtxManager() as example):
    ...

with (
    CtxManager1(),
    CtxManager2()
):
    ...

with (CtxManager1() as example,
      CtxManager2()):
    ...

with (CtxManager1(),
      CtxManager2() as example):
    ...

with (
    CtxManager1() as example1,
    CtxManager2() as example2
):
    ...

it is also possible to use a trailing comma at the end of the enclosed group:

with (
    CtxManager1() as example1,
    CtxManager2() as example2,
    CtxManager3() as example3,
):
    ...

This new syntax uses the non LL(1) capacities of the new parser. Check PEP 617 [https://peps.python.org/pep-0617/] for more details.

(Contributed by Guido van Rossum, Pablo Galindo and Lysandros Nikolaou in bpo-12782 [https://bugs.python.org/issue?@action=redirect&bpo=12782] and bpo-40334 [https://bugs.python.org/issue?@action=redirect&bpo=40334].)

Better error messages

SyntaxErrors

When parsing code that contains unclosed parentheses or brackets the interpreter now includes the location of the unclosed bracket of parentheses instead of displaying SyntaxError: unexpected EOF while parsing or pointing to some incorrect location. For instance, consider the following code (notice the unclosed ‘{‘):

expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
            38: 4, 39: 4, 45: 5, 46: 5, 47: 5, 48: 5, 49: 5, 54: 6,
some_other_code = foo()

Previous versions of the interpreter reported confusing places as the location of the syntax error:

File "example.py", line 3
    some_other_code = foo()
                    ^
SyntaxError: invalid syntax

but in Python 3.10 a more informative error is emitted:

File "example.py", line 1
    expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
               ^
SyntaxError: '{' was never closed

In a similar way, errors involving unclosed string literals (single and triple quoted) now point to the start of the string instead of reporting EOF/EOL.

These improvements are inspired by previous work in the PyPy interpreter.

(Contributed by Pablo Galindo in bpo-42864 [https://bugs.python.org/issue?@action=redirect&bpo=42864] and Batuhan Taskaya in bpo-40176 [https://bugs.python.org/issue?@action=redirect&bpo=40176].)

SyntaxError exceptions raised by the interpreter will now highlight the full error range of the expression that constitutes the syntax error itself, instead of just where the problem is detected. In this way, instead of displaying (before Python 3.10):

>>> foo(x, z for z in range(10), t, w)
  File "<stdin>", line 1
    foo(x, z for z in range(10), t, w)
           ^
SyntaxError: Generator expression must be parenthesized

now Python 3.10 will display the exception as:

>>> foo(x, z for z in range(10), t, w)
  File "<stdin>", line 1
    foo(x, z for z in range(10), t, w)
           ^^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized

This improvement was contributed by Pablo Galindo in bpo-43914 [https://bugs.python.org/issue?@action=redirect&bpo=43914].

A considerable amount of new specialized messages for SyntaxError exceptions have been incorporated. Some of the most notable ones are as follows:

Missing : before blocks:

>>> if rocket.position > event_horizon
  File "<stdin>", line 1
    if rocket.position > event_horizon
                                      ^
SyntaxError: expected ':'

(Contributed by Pablo Galindo in bpo-42997 [https://bugs.python.org/issue?@action=redirect&bpo=42997].)

Unparenthesised tuples in comprehensions targets:

>>> {x,y for x,y in zip('abcd', '1234')}
  File "<stdin>", line 1
    {x,y for x,y in zip('abcd', '1234')}
     ^
SyntaxError: did you forget parentheses around the comprehension target?

(Contributed by Pablo Galindo in bpo-43017 [https://bugs.python.org/issue?@action=redirect&bpo=43017].)

Missing commas in collection literals and between expressions:

>>> items = {
... x: 1,
... y: 2
... z: 3,
  File "<stdin>", line 3
    y: 2
       ^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

(Contributed by Pablo Galindo in bpo-43822 [https://bugs.python.org/issue?@action=redirect&bpo=43822].)

Multiple Exception types without parentheses:

>>> try:
...     build_dyson_sphere()
... except NotEnoughScienceError, NotEnoughResourcesError:
  File "<stdin>", line 3
    except NotEnoughScienceError, NotEnoughResourcesError:
           ^
SyntaxError: multiple exception types must be parenthesized

(Contributed by Pablo Galindo in bpo-43149 [https://bugs.python.org/issue?@action=redirect&bpo=43149].)

Missing : and values in dictionary literals:

>>> values = {
... x: 1,
... y: 2,
... z:
... }
  File "<stdin>", line 4
    z:
     ^
SyntaxError: expression expected after dictionary key and ':'

>>> values = {x:1, y:2, z w:3}
  File "<stdin>", line 1
    values = {x:1, y:2, z w:3}
                        ^
SyntaxError: ':' expected after dictionary key

(Contributed by Pablo Galindo in bpo-43823 [https://bugs.python.org/issue?@action=redirect&bpo=43823].)

try blocks without except or finally blocks:

>>> try:
...     x = 2
... something = 3
  File "<stdin>", line 3
    something  = 3
    ^^^^^^^^^
SyntaxError: expected 'except' or 'finally' block

(Contributed by Pablo Galindo in bpo-44305 [https://bugs.python.org/issue?@action=redirect&bpo=44305].)

Usage of = instead of == in comparisons:

>>> if rocket.position = event_horizon:
  File "<stdin>", line 1
    if rocket.position = event_horizon:
                       ^
SyntaxError: cannot assign to attribute here. Maybe you meant '==' instead of '='?

(Contributed by Pablo Galindo in bpo-43797 [https://bugs.python.org/issue?@action=redirect&bpo=43797].)

Usage of * in f-strings:

>>> f"Black holes {*all_black_holes} and revelations"
  File "<stdin>", line 1
    (*all_black_holes)
     ^
SyntaxError: f-string: cannot use starred expression here

(Contributed by Pablo Galindo in bpo-41064 [https://bugs.python.org/issue?@action=redirect&bpo=41064].)

IndentationErrors

Many IndentationError exceptions now have more context regarding what kind of block was expecting an indentation, including the location of the statement:

>>> def foo():
...    if lel:
...    x = 2
  File "<stdin>", line 3
    x = 2
    ^
IndentationError: expected an indented block after 'if' statement in line 2

AttributeErrors

When printing AttributeError, PyErr_Display() will offer suggestions of similar attribute names in the object that the exception was raised from:

>>> collections.namedtoplo
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: namedtuple?

(Contributed by Pablo Galindo in bpo-38530 [https://bugs.python.org/issue?@action=redirect&bpo=38530].)

경고

Notice this won’t work if PyErr_Display() is not called to display the error which can happen if some other custom error display function is used. This is a common scenario in some REPLs like IPython.

NameErrors

When printing NameError raised by the interpreter, PyErr_Display() will offer suggestions of similar variable names in the function that the exception was raised from:

>>> schwarzschild_black_hole = None
>>> schwarschild_black_hole
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?

(Contributed by Pablo Galindo in bpo-38530 [https://bugs.python.org/issue?@action=redirect&bpo=38530].)

경고

Notice this won’t work if PyErr_Display() is not called to display the error, which can happen if some other custom error display function is used. This is a common scenario in some REPLs like IPython.

PEP 626: Precise line numbers for debugging and other tools

PEP 626 brings more precise and reliable line numbers for debugging, profiling and coverage tools. Tracing events, with the correct line number, are generated for all lines of code executed and only for lines of code that are executed.

The f_lineno attribute of frame objects will always contain the expected line number.

The co_lnotab attribute of code objects is deprecated and will be removed in 3.12. Code that needs to convert from offset to line number should use the new co_lines() method instead.

PEP 634: Structural Pattern Matching

Structural pattern matching has been added in the form of a match statement and case statements of patterns with associated actions. Patterns consist of sequences, mappings, primitive data types as well as class instances. Pattern matching enables programs to extract information from complex data types, branch on the structure of data, and apply specific actions based on different forms of data.

Syntax and operations

The generic syntax of pattern matching is:

match subject:
    case <pattern_1>:
        <action_1>
    case <pattern_2>:
        <action_2>
    case <pattern_3>:
        <action_3>
    case _:
        <action_wildcard>

A match statement takes an expression and compares its value to successive patterns given as one or more case blocks. Specifically, pattern matching operates by:

using data with type and shape (the subject)

evaluating the subject in the match statement

comparing the subject with each pattern in a case statement from top to bottom until a match is confirmed.

executing the action associated with the pattern of the confirmed match

If an exact match is not confirmed, the last case, a wildcard _, if provided, will be used as the matching case. If an exact match is not confirmed and a wildcard case does not exist, the entire match block is a no-op.

Declarative approach

Readers may be aware of pattern matching through the simple example of matching a subject (data object) to a literal (pattern) with the switch statement found in C, Java or JavaScript (and many other languages). Often the switch statement is used for comparison of an object/expression with case statements containing literals.

More powerful examples of pattern matching can be found in languages such as Scala and Elixir. With structural pattern matching, the approach is “declarative” and explicitly states the conditions (the patterns) for data to match.

While an “imperative” series of instructions using nested “if” statements could be used to accomplish something similar to structural pattern matching, it is less clear than the “declarative” approach. Instead the “declarative” approach states the conditions to meet for a match and is more readable through its explicit patterns. While structural pattern matching can be used in its simplest form comparing a variable to a literal in a case statement, its true value for Python lies in its handling of the subject’s type and shape.

Simple pattern: match to a literal

Let’s look at this example as pattern matching in its simplest form: a value, the subject, being matched to several literals, the patterns. In the example below, status is the subject of the match statement. The patterns are each of the case statements, where literals represent request status codes. The associated action to the case is executed after a match:

def http_error(status):
    match status:
        case 400:
            return "Bad request"
        case 404:
            return "Not found"
        case 418:
            return "I'm a teapot"
        case _:
            return "Something's wrong with the internet"

If the above function is passed a status of 418, “I’m a teapot” is returned. If the above function is passed a status of 500, the case statement with _ will match as a wildcard, and “Something’s wrong with the internet” is returned. Note the last block: the variable name, _, acts as a wildcard and insures the subject will always match. The use of _ is optional.

You can combine several literals in a single pattern using | (“or”):

case 401 | 403 | 404:
    return "Not allowed"

Behavior without the wildcard

If we modify the above example by removing the last case block, the example becomes:

def http_error(status):
    match status:
        case 400:
            return "Bad request"
        case 404:
            return "Not found"
        case 418:
            return "I'm a teapot"

Without the use of _ in a case statement, a match may not exist. If no match exists, the behavior is a no-op. For example, if status of 500 is passed, a no-op occurs.

Patterns with a literal and variable

Patterns can look like unpacking assignments, and a pattern may be used to bind variables. In this example, a data point can be unpacked to its x-coordinate and y-coordinate:

# point is an (x, y) tuple
match point:
    case (0, 0):
        print("Origin")
    case (0, y):
        print(f"Y={y}")
    case (x, 0):
        print(f"X={x}")
    case (x, y):
        print(f"X={x}, Y={y}")
    case _:
        raise ValueError("Not a point")

The first pattern has two literals, (0, 0), and may be thought of as an extension of the literal pattern shown above. The next two patterns combine a literal and a variable, and the variable binds a value from the subject (point). The fourth pattern captures two values, which makes it conceptually similar to the unpacking assignment (x, y) = point.

Patterns and classes

If you are using classes to structure your data, you can use as a pattern the class name followed by an argument list resembling a constructor. This pattern has the ability to capture class attributes into variables:

class Point:
    x: int
    y: int

def location(point):
    match point:
        case Point(x=0, y=0):
            print("Origin is the point's location.")
        case Point(x=0, y=y):
            print(f"Y={y} and the point is on the y-axis.")
        case Point(x=x, y=0):
            print(f"X={x} and the point is on the x-axis.")
        case Point():
            print("The point is located somewhere else on the plane.")
        case _:
            print("Not a point")

Patterns with positional parameters

You can use positional parameters with some builtin classes that provide an ordering for their attributes (e.g. dataclasses). You can also define a specific position for attributes in patterns by setting the __match_args__ special attribute in your classes. If it’s set to (“x”, “y”), the following patterns are all equivalent (and all bind the y attribute to the var variable):

Point(1, var)
Point(1, y=var)
Point(x=1, y=var)
Point(y=var, x=1)

Nested patterns

Patterns can be arbitrarily nested. For example, if our data is a short list of points, it could be matched like this:

match points:
    case []:
        print("No points in the list.")
    case [Point(0, 0)]:
        print("The origin is the only point in the list.")
    case [Point(x, y)]:
        print(f"A single point {x}, {y} is in the list.")
    case [Point(0, y1), Point(0, y2)]:
        print(f"Two points on the Y axis at {y1}, {y2} are in the list.")
    case _:
        print("Something else is found in the list.")

Complex patterns and the wildcard

To this point, the examples have used _ alone in the last case statement. A wildcard can be used in more complex patterns, such as ('error', code, _). For example:

match test_variable:
    case ('warning', code, 40):
        print("A warning has been received.")
    case ('error', code, _):
        print(f"An error {code} occurred.")

In the above case, test_variable will match for (‘error’, code, 100) and (‘error’, code, 800).

Guard

We can add an if clause to a pattern, known as a “guard”. If the guard is false, match goes on to try the next case block. Note that value capture happens before the guard is evaluated:

match point:
    case Point(x, y) if x == y:
        print(f"The point is located on the diagonal Y=X at {x}.")
    case Point(x, y):
        print(f"Point is not on the diagonal.")

Other Key Features

Several other key features:

Like unpacking assignments, tuple and list patterns have exactly the same meaning and actually match arbitrary sequences. Technically, the subject must be a sequence. Therefore, an important exception is that patterns don’t match iterators. Also, to prevent a common mistake, sequence patterns don’t match strings.

Sequence patterns support wildcards: [x, y, *rest] and (x, y, *rest) work similar to wildcards in unpacking assignments. The name after * may also be _, so (x, y, *_) matches a sequence of at least two items without binding the remaining items.

Mapping patterns: {"bandwidth": b, "latency": l} captures the "bandwidth" and "latency" values from a dict. Unlike sequence patterns, extra keys are ignored. A wildcard **rest is also supported. (But **_ would be redundant, so is not allowed.)

Subpatterns may be captured using the as keyword:

case (Point(x1, y1), Point(x2, y2) as p2): ...

This binds x1, y1, x2, y2 like you would expect without the as clause, and p2 to the entire second item of the subject.

Most literals are compared by equality. However, the singletons True, False and None are compared by identity.

Named constants may be used in patterns. These named constants must be dotted names to prevent the constant from being interpreted as a capture variable:

from enum import Enum
class Color(Enum):
    RED = 0
    GREEN = 1
    BLUE = 2

color = Color.GREEN
match color:
    case Color.RED:
        print("I see red!")
    case Color.GREEN:
        print("Grass is green")
    case Color.BLUE:
        print("I'm feeling the blues :(")

For the full specification see PEP 634 [https://peps.python.org/pep-0634/]. Motivation and rationale are in PEP 635 [https://peps.python.org/pep-0635/], and a longer tutorial is in PEP 636 [https://peps.python.org/pep-0636/].

Optional EncodingWarning and encoding="locale" option

The default encoding of TextIOWrapper and open() is platform and locale dependent. Since UTF-8 is used on most Unix platforms, omitting encoding option when opening UTF-8 files (e.g. JSON, YAML, TOML, Markdown) is a very common bug. For example:

# BUG: "rb" mode or encoding="utf-8" should be used.
with open("data.json") as f:
    data = json.load(f)

To find this type of bug, an optional EncodingWarning is added. It is emitted when sys.flags.warn_default_encoding is true and locale-specific default encoding is used.

-X warn_default_encoding option and PYTHONWARNDEFAULTENCODING are added to enable the warning.

See Text Encoding for more information.

New Features Related to Type Hints

This section covers major changes affecting PEP 484 [https://peps.python.org/pep-0484/] type hints and the typing module.

PEP 604: New Type Union Operator

A new type union operator was introduced which enables the syntax X | Y. This provides a cleaner way of expressing ‘either type X or type Y’ instead of using typing.Union, especially in type hints.

In previous versions of Python, to apply a type hint for functions accepting arguments of multiple types, typing.Union was used:

def square(number: Union[int, float]) -> Union[int, float]:
    return number ** 2

Type hints can now be written in a more succinct manner:

def square(number: int | float) -> int | float:
    return number ** 2

This new syntax is also accepted as the second argument to isinstance() and issubclass():

>>> isinstance(1, int | str)
True

See Union Type and PEP 604 [https://peps.python.org/pep-0604/] for more details.

(Contributed by Maggie Moss and Philippe Prados in bpo-41428 [https://bugs.python.org/issue?@action=redirect&bpo=41428], with additions by Yurii Karabas and Serhiy Storchaka in bpo-44490 [https://bugs.python.org/issue?@action=redirect&bpo=44490].)

PEP 612: Parameter Specification Variables

Two new options to improve the information provided to static type checkers for PEP 484 [https://peps.python.org/pep-0484/]‘s Callable have been added to the typing module.

The first is the parameter specification variable. They are used to forward the parameter types of one callable to another callable – a pattern commonly found in higher order functions and decorators. Examples of usage can be found in typing.ParamSpec. Previously, there was no easy way to type annotate dependency of parameter types in such a precise manner.

The second option is the new Concatenate operator. It’s used in conjunction with parameter specification variables to type annotate a higher order callable which adds or removes parameters of another callable. Examples of usage can be found in typing.Concatenate.

See typing.Callable, typing.ParamSpec, typing.Concatenate, typing.ParamSpecArgs, typing.ParamSpecKwargs, and PEP 612 [https://peps.python.org/pep-0612/] for more details.

(Contributed by Ken Jin in bpo-41559 [https://bugs.python.org/issue?@action=redirect&bpo=41559], with minor enhancements by Jelle Zijlstra in bpo-43783 [https://bugs.python.org/issue?@action=redirect&bpo=43783]. PEP written by Mark Mendoza.)

PEP 613: TypeAlias

PEP 484 [https://peps.python.org/pep-0484/] introduced the concept of type aliases, only requiring them to be top-level unannotated assignments. This simplicity sometimes made it difficult for type checkers to distinguish between type aliases and ordinary assignments, especially when forward references or invalid types were involved. Compare:

StrCache = 'Cache[str]'  # a type alias
LOG_PREFIX = 'LOG[DEBUG]'  # a module constant

Now the typing module has a special value TypeAlias which lets you declare type aliases more explicitly:

StrCache: TypeAlias = 'Cache[str]'  # a type alias
LOG_PREFIX = 'LOG[DEBUG]'  # a module constant

See PEP 613 [https://peps.python.org/pep-0613/] for more details.

(Contributed by Mikhail Golubev in bpo-41923 [https://bugs.python.org/issue?@action=redirect&bpo=41923].)

PEP 647: User-Defined Type Guards

TypeGuard has been added to the typing module to annotate type guard functions and improve information provided to static type checkers during type narrowing. For more information, please see TypeGuard‘s documentation, and PEP 647 [https://peps.python.org/pep-0647/].

(Contributed by Ken Jin and Guido van Rossum in bpo-43766 [https://bugs.python.org/issue?@action=redirect&bpo=43766]. PEP written by Eric Traut.)

Other Language Changes

The int type has a new method int.bit_count(), returning the number of ones in the binary expansion of a given integer, also known as the population count. (Contributed by Niklas Fiekas in bpo-29882 [https://bugs.python.org/issue?@action=redirect&bpo=29882].)

The views returned by dict.keys(), dict.values() and dict.items() now all have a mapping attribute that gives a types.MappingProxyType object wrapping the original dictionary. (Contributed by Dennis Sweeney in bpo-40890 [https://bugs.python.org/issue?@action=redirect&bpo=40890].)

PEP 618 [https://peps.python.org/pep-0618/]: The zip() function now has an optional strict flag, used to require that all the iterables have an equal length.

Builtin and extension functions that take integer arguments no longer accept Decimals, Fractions and other objects that can be converted to integers only with a loss (e.g. that have the __int__() method but do not have the __index__() method). (Contributed by Serhiy Storchaka in bpo-37999 [https://bugs.python.org/issue?@action=redirect&bpo=37999].)

If object.__ipow__() returns NotImplemented, the operator will correctly fall back to object.__pow__() and object.__rpow__() as expected. (Contributed by Alex Shkop in bpo-38302 [https://bugs.python.org/issue?@action=redirect&bpo=38302].)

Assignment expressions can now be used unparenthesized within set literals and set comprehensions, as well as in sequence indexes (but not slices).

Functions have a new __builtins__ attribute which is used to look for builtin symbols when a function is executed, instead of looking into __globals__['__builtins__']. The attribute is initialized from __globals__["__builtins__"] if it exists, else from the current builtins. (Contributed by Mark Shannon in bpo-42990 [https://bugs.python.org/issue?@action=redirect&bpo=42990].)

Two new builtin functions – aiter() and anext() have been added to provide asynchronous counterparts to iter() and next(), respectively. (Contributed by Joshua Bronson, Daniel Pope, and Justin Wang in bpo-31861 [https://bugs.python.org/issue?@action=redirect&bpo=31861].)

Static methods (@staticmethod) and class methods (@classmethod) now inherit the method attributes (__module__, __name__, __qualname__, __doc__, __annotations__) and have a new __wrapped__ attribute. Moreover, static methods are now callable as regular functions. (Contributed by Victor Stinner in bpo-43682 [https://bugs.python.org/issue?@action=redirect&bpo=43682].)

Annotations for complex targets (everything beside simple name targets defined by PEP 526 [https://peps.python.org/pep-0526/]) no longer cause any runtime effects with from __future__ import annotations. (Contributed by Batuhan Taskaya in bpo-42737 [https://bugs.python.org/issue?@action=redirect&bpo=42737].)

Class and module objects now lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object’s __dict__ for backwards compatibility. This improves the best practices for working with __annotations__; for more information, please see Annotations Best Practices. (Contributed by Larry Hastings in bpo-43901 [https://bugs.python.org/issue?@action=redirect&bpo=43901].)

Annotations consist of yield, yield from, await or named expressions are now forbidden under from __future__ import annotations due to their side effects. (Contributed by Batuhan Taskaya in bpo-42725 [https://bugs.python.org/issue?@action=redirect&bpo=42725].)

Usage of unbound variables, super() and other expressions that might alter the processing of symbol table as annotations are now rendered effectless under from __future__ import annotations. (Contributed by Batuhan Taskaya in bpo-42725 [https://bugs.python.org/issue?@action=redirect&bpo=42725].)

Hashes of NaN values of both float type and decimal.Decimal type now depend on object identity. Formerly, they always hashed to 0 even though NaN values are not equal to one another. This caused potentially quadratic runtime behavior due to excessive hash collisions when creating dictionaries and sets containing multiple NaNs. (Contributed by Raymond Hettinger in bpo-43475 [https://bugs.python.org/issue?@action=redirect&bpo=43475].)

A SyntaxError (instead of a NameError) will be raised when deleting the __debug__ constant. (Contributed by Donghee Na in bpo-45000 [https://bugs.python.org/issue?@action=redirect&bpo=45000].)

SyntaxError exceptions now have end_lineno and end_offset attributes. They will be None if not determined. (Contributed by Pablo Galindo in bpo-43914 [https://bugs.python.org/issue?@action=redirect&bpo=43914].)

New Modules

None.

Improved Modules

asyncio

Add missing connect_accepted_socket() method. (Contributed by Alex Grönholm in bpo-41332 [https://bugs.python.org/issue?@action=redirect&bpo=41332].)

argparse

Misleading phrase “optional arguments” was replaced with “options” in argparse help. Some tests might require adaptation if they rely on exact output match. (Contributed by Raymond Hettinger in bpo-9694 [https://bugs.python.org/issue?@action=redirect&bpo=9694].)

array

The index() method of array.array now has optional start and stop parameters. (Contributed by Anders Lorentsen and Zackery Spytz in bpo-31956 [https://bugs.python.org/issue?@action=redirect&bpo=31956].)

asynchat, asyncore, smtpd

These modules have been marked as deprecated in their module documentation since Python 3.6. An import-time DeprecationWarning has now been added to all three of these modules.

base64

Add base64.b32hexencode() and base64.b32hexdecode() to support the Base32 Encoding with Extended Hex Alphabet.

bdb

Add clearBreakpoints() to reset all set breakpoints. (Contributed by Irit Katriel in bpo-24160 [https://bugs.python.org/issue?@action=redirect&bpo=24160].)

bisect

Added the possibility of providing a key function to the APIs in the bisect module. (Contributed by Raymond Hettinger in bpo-4356 [https://bugs.python.org/issue?@action=redirect&bpo=4356].)

codecs

Add a codecs.unregister() function to unregister a codec search function. (Contributed by Hai Shi in bpo-41842 [https://bugs.python.org/issue?@action=redirect&bpo=41842].)

collections.abc

The __args__ of the parameterized generic for collections.abc.Callable are now consistent with typing.Callable. collections.abc.Callable generic now flattens type parameters, similar to what typing.Callable currently does. This means that collections.abc.Callable[[int, str], str] will have __args__ of (int, str, str); previously this was ([int, str], str). To allow this change, types.GenericAlias can now be subclassed, and a subclass will be returned when subscripting the collections.abc.Callable type. Note that a TypeError may be raised for invalid forms of parameterizing collections.abc.Callable which may have passed silently in Python 3.9. (Contributed by Ken Jin in bpo-42195 [https://bugs.python.org/issue?@action=redirect&bpo=42195].)

contextlib

Add a contextlib.aclosing() context manager to safely close async generators and objects representing asynchronously released resources. (Contributed by Joongi Kim and John Belmonte in bpo-41229 [https://bugs.python.org/issue?@action=redirect&bpo=41229].)

Add asynchronous context manager support to contextlib.nullcontext(). (Contributed by Tom Gringauz in bpo-41543 [https://bugs.python.org/issue?@action=redirect&bpo=41543].)

Add AsyncContextDecorator, for supporting usage of async context managers as decorators.

curses

The extended color functions added in ncurses 6.1 will be used transparently by curses.color_content(), curses.init_color(), curses.init_pair(), and curses.pair_content(). A new function, curses.has_extended_color_support(), indicates whether extended color support is provided by the underlying ncurses library. (Contributed by Jeffrey Kintscher and Hans Petter Jansson in bpo-36982 [https://bugs.python.org/issue?@action=redirect&bpo=36982].)

The BUTTON5_* constants are now exposed in the curses module if they are provided by the underlying curses library. (Contributed by Zackery Spytz in bpo-39273 [https://bugs.python.org/issue?@action=redirect&bpo=39273].)

dataclasses

__slots__

Added slots parameter in dataclasses.dataclass() decorator. (Contributed by Yurii Karabas in bpo-42269 [https://bugs.python.org/issue?@action=redirect&bpo=42269])

Keyword-only fields

dataclasses now supports fields that are keyword-only in the generated __init__ method. There are a number of ways of specifying keyword-only fields.

You can say that every field is keyword-only:

from dataclasses import dataclass

@dataclass(kw_only=True)
class Birthday:
    name: str
    birthday: datetime.date

Both name and birthday are keyword-only parameters to the generated __init__ method.

You can specify keyword-only on a per-field basis:

from dataclasses import dataclass, field

@dataclass
class Birthday:
    name: str
    birthday: datetime.date = field(kw_only=True)

Here only birthday is keyword-only. If you set kw_only on individual fields, be aware that there are rules about re-ordering fields due to keyword-only fields needing to follow non-keyword-only fields. See the full dataclasses documentation for details.

You can also specify that all fields following a KW_ONLY marker are keyword-only. This will probably be the most common usage:

from dataclasses import dataclass, KW_ONLY

@dataclass
class Point:
    x: float
    y: float
    _: KW_ONLY
    z: float = 0.0
    t: float = 0.0

Here, z and t are keyword-only parameters, while x and y are not. (Contributed by Eric V. Smith in bpo-43532 [https://bugs.python.org/issue?@action=redirect&bpo=43532].)

distutils

The entire distutils package is deprecated, to be removed in Python 3.12. Its functionality for specifying package builds has already been completely replaced by third-party packages setuptools and packaging, and most other commonly used APIs are available elsewhere in the standard library (such as platform, shutil, subprocess or sysconfig). There are no plans to migrate any other functionality from distutils, and applications that are using other functions should plan to make private copies of the code. Refer to PEP 632 [https://peps.python.org/pep-0632/] for discussion.

The bdist_wininst command deprecated in Python 3.8 has been removed. The bdist_wheel command is now recommended to distribute binary packages on Windows. (Contributed by Victor Stinner in bpo-42802 [https://bugs.python.org/issue?@action=redirect&bpo=42802].)

doctest

When a module does not define __loader__, fall back to __spec__.loader. (Contributed by Brett Cannon in bpo-42133 [https://bugs.python.org/issue?@action=redirect&bpo=42133].)

encodings

encodings.normalize_encoding() now ignores non-ASCII characters. (Contributed by Hai Shi in bpo-39337 [https://bugs.python.org/issue?@action=redirect&bpo=39337].)

enum

Enum __repr__() now returns enum_name.member_name and __str__() now returns member_name. Stdlib enums available as module constants have a repr() of module_name.member_name. (Contributed by Ethan Furman in bpo-40066 [https://bugs.python.org/issue?@action=redirect&bpo=40066].)

Add enum.StrEnum for enums where all members are strings. (Contributed by Ethan Furman in bpo-41816 [https://bugs.python.org/issue?@action=redirect&bpo=41816].)

fileinput

Add encoding and errors parameters in fileinput.input() and fileinput.FileInput. (Contributed by Inada Naoki in bpo-43712 [https://bugs.python.org/issue?@action=redirect&bpo=43712].)

fileinput.hook_compressed() now returns TextIOWrapper object when mode is “r” and file is compressed, like uncompressed files. (Contributed by Inada Naoki in bpo-5758 [https://bugs.python.org/issue?@action=redirect&bpo=5758].)

faulthandler

The faulthandler module now detects if a fatal error occurs during a garbage collector collection. (Contributed by Victor Stinner in bpo-44466 [https://bugs.python.org/issue?@action=redirect&bpo=44466].)

gc

Add audit hooks for gc.get_objects(), gc.get_referrers() and gc.get_referents(). (Contributed by Pablo Galindo in bpo-43439 [https://bugs.python.org/issue?@action=redirect&bpo=43439].)

glob

Add the root_dir and dir_fd parameters in glob() and iglob() which allow to specify the root directory for searching. (Contributed by Serhiy Storchaka in bpo-38144 [https://bugs.python.org/issue?@action=redirect&bpo=38144].)

hashlib

The hashlib module requires OpenSSL 1.1.1 or newer. (Contributed by Christian Heimes in PEP 644 [https://peps.python.org/pep-0644/] and bpo-43669 [https://bugs.python.org/issue?@action=redirect&bpo=43669].)

The hashlib module has preliminary support for OpenSSL 3.0.0. (Contributed by Christian Heimes in bpo-38820 [https://bugs.python.org/issue?@action=redirect&bpo=38820] and other issues.)

The pure-Python fallback of pbkdf2_hmac() is deprecated. In the future PBKDF2-HMAC will only be available when Python has been built with OpenSSL support. (Contributed by Christian Heimes in bpo-43880 [https://bugs.python.org/issue?@action=redirect&bpo=43880].)

hmac

The hmac module now uses OpenSSL’s HMAC implementation internally. (Contributed by Christian Heimes in bpo-40645 [https://bugs.python.org/issue?@action=redirect&bpo=40645].)

IDLE and idlelib

Make IDLE invoke sys.excepthook() (when started without ‘-n’). User hooks were previously ignored. (Contributed by Ken Hilton in bpo-43008 [https://bugs.python.org/issue?@action=redirect&bpo=43008].)

Rearrange the settings dialog. Split the General tab into Windows and Shell/Ed tabs. Move help sources, which extend the Help menu, to the Extensions tab. Make space for new options and shorten the dialog. The latter makes the dialog better fit small screens. (Contributed by Terry Jan Reedy in bpo-40468 [https://bugs.python.org/issue?@action=redirect&bpo=40468].) Move the indent space setting from the Font tab to the new Windows tab. (Contributed by Mark Roseman and Terry Jan Reedy in bpo-33962 [https://bugs.python.org/issue?@action=redirect&bpo=33962].)

The changes above were backported to a 3.9 maintenance release.

Add a Shell sidebar. Move the primary prompt (‘>>>’) to the sidebar. Add secondary prompts (’…’) to the sidebar. Left click and optional drag selects one or more lines of text, as with the editor line number sidebar. Right click after selecting text lines displays a context menu with ‘copy with prompts’. This zips together prompts from the sidebar with lines from the selected text. This option also appears on the context menu for the text. (Contributed by Tal Einat in bpo-37903 [https://bugs.python.org/issue?@action=redirect&bpo=37903].)

Use spaces instead of tabs to indent interactive code. This makes interactive code entries ‘look right’. Making this feasible was a major motivation for adding the shell sidebar. (Contributed by Terry Jan Reedy in bpo-37892 [https://bugs.python.org/issue?@action=redirect&bpo=37892].)

Highlight the new soft keywords match, case, and _ in pattern-matching statements. However, this highlighting is not perfect and will be incorrect in some rare cases, including some _-s in case patterns. (Contributed by Tal Einat in bpo-44010 [https://bugs.python.org/issue?@action=redirect&bpo=44010].)

New in 3.10 maintenance releases.

Apply syntax highlighting to .pyi files. (Contributed by Alex Waygood and Terry Jan Reedy in bpo-45447 [https://bugs.python.org/issue?@action=redirect&bpo=45447].)

Include prompts when saving Shell with inputs and outputs. (Contributed by Terry Jan Reedy in gh-95191 [https://github.com/python/cpython/issues/95191].)

importlib.metadata

Feature parity with importlib_metadata 4.6 (history [https://importlib-metadata.readthedocs.io/en/latest/history.html]).

importlib.metadata entry points now provide a nicer experience for selecting entry points by group and name through a new importlib.metadata.EntryPoints class. See the Compatibility Note in the docs for more info on the deprecation and usage.

Added importlib.metadata.packages_distributions() for resolving top-level Python modules and packages to their importlib.metadata.Distribution.

inspect

When a module does not define __loader__, fall back to __spec__.loader. (Contributed by Brett Cannon in bpo-42133 [https://bugs.python.org/issue?@action=redirect&bpo=42133].)

Add inspect.get_annotations(), which safely computes the annotations defined on an object. It works around the quirks of accessing the annotations on various types of objects, and makes very few assumptions about the object it examines. inspect.get_annotations() can also correctly un-stringize stringized annotations. inspect.get_annotations() is now considered best practice for accessing the annotations dict defined on any Python object; for more information on best practices for working with annotations, please see Annotations Best Practices. Relatedly, inspect.signature(), inspect.Signature.from_callable(), and inspect.Signature.from_function() now call inspect.get_annotations() to retrieve annotations. This means inspect.signature() and inspect.Signature.from_callable() can also now un-stringize stringized annotations. (Contributed by Larry Hastings in bpo-43817 [https://bugs.python.org/issue?@action=redirect&bpo=43817].)

itertools

Add itertools.pairwise(). (Contributed by Raymond Hettinger in bpo-38200 [https://bugs.python.org/issue?@action=redirect&bpo=38200].)

linecache

When a module does not define __loader__, fall back to __spec__.loader. (Contributed by Brett Cannon in bpo-42133 [https://bugs.python.org/issue?@action=redirect&bpo=42133].)

os

Add os.cpu_count() support for VxWorks RTOS. (Contributed by Peixing Xin in bpo-41440 [https://bugs.python.org/issue?@action=redirect&bpo=41440].)

Add a new function os.eventfd() and related helpers to wrap the eventfd2 syscall on Linux. (Contributed by Christian Heimes in bpo-41001 [https://bugs.python.org/issue?@action=redirect&bpo=41001].)

Add os.splice() that allows to move data between two file descriptors without copying between kernel address space and user address space, where one of the file descriptors must refer to a pipe. (Contributed by Pablo Galindo in bpo-41625 [https://bugs.python.org/issue?@action=redirect&bpo=41625].)

Add O_EVTONLY, O_FSYNC, O_SYMLINK and O_NOFOLLOW_ANY for macOS. (Contributed by Donghee Na in bpo-43106 [https://bugs.python.org/issue?@action=redirect&bpo=43106].)

os.path

os.path.realpath() now accepts a strict keyword-only argument. When set to True, OSError is raised if a path doesn’t exist or a symlink loop is encountered. (Contributed by Barney Gale in bpo-43757 [https://bugs.python.org/issue?@action=redirect&bpo=43757].)

pathlib

Add slice support to PurePath.parents. (Contributed by Joshua Cannon in bpo-35498 [https://bugs.python.org/issue?@action=redirect&bpo=35498].)

Add negative indexing support to PurePath.parents. (Contributed by Yaroslav Pankovych in bpo-21041 [https://bugs.python.org/issue?@action=redirect&bpo=21041].)

Add Path.hardlink_to method that supersedes link_to(). The new method has the same argument order as symlink_to(). (Contributed by Barney Gale in bpo-39950 [https://bugs.python.org/issue?@action=redirect&bpo=39950].)

pathlib.Path.stat() and chmod() now accept a follow_symlinks keyword-only argument for consistency with corresponding functions in the os module. (Contributed by Barney Gale in bpo-39906 [https://bugs.python.org/issue?@action=redirect&bpo=39906].)

platform

Add platform.freedesktop_os_release() to retrieve operation system identification from freedesktop.org os-release [https://www.freedesktop.org/software/systemd/man/os-release.html] standard file. (Contributed by Christian Heimes in bpo-28468 [https://bugs.python.org/issue?@action=redirect&bpo=28468].)

pprint

pprint.pprint() now accepts a new underscore_numbers keyword argument. (Contributed by sblondon in bpo-42914 [https://bugs.python.org/issue?@action=redirect&bpo=42914].)

pprint can now pretty-print dataclasses.dataclass instances. (Contributed by Lewis Gaul in bpo-43080 [https://bugs.python.org/issue?@action=redirect&bpo=43080].)

py_compile

Add --quiet option to command-line interface of py_compile. (Contributed by Gregory Schevchenko in bpo-38731 [https://bugs.python.org/issue?@action=redirect&bpo=38731].)

pyclbr

Add an end_lineno attribute to the Function and Class objects in the tree returned by pyclbr.readmodule() and pyclbr.readmodule_ex(). It matches the existing (start) lineno. (Contributed by Aviral Srivastava in bpo-38307 [https://bugs.python.org/issue?@action=redirect&bpo=38307].)

shelve

The shelve module now uses pickle.DEFAULT_PROTOCOL by default instead of pickle protocol 3 when creating shelves. (Contributed by Zackery Spytz in bpo-34204 [https://bugs.python.org/issue?@action=redirect&bpo=34204].)

statistics

Add covariance(), Pearson’s correlation(), and simple linear_regression() functions. (Contributed by Tymoteusz Wołodźko in bpo-38490 [https://bugs.python.org/issue?@action=redirect&bpo=38490].)

site

When a module does not define __loader__, fall back to __spec__.loader. (Contributed by Brett Cannon in bpo-42133 [https://bugs.python.org/issue?@action=redirect&bpo=42133].)

socket

The exception socket.timeout is now an alias of TimeoutError. (Contributed by Christian Heimes in bpo-42413 [https://bugs.python.org/issue?@action=redirect&bpo=42413].)

Add option to create MPTCP sockets with IPPROTO_MPTCP (Contributed by Rui Cunha in bpo-43571 [https://bugs.python.org/issue?@action=redirect&bpo=43571].)

Add IP_RECVTOS option to receive the type of service (ToS) or DSCP/ECN fields (Contributed by Georg Sauthoff in bpo-44077 [https://bugs.python.org/issue?@action=redirect&bpo=44077].)

ssl

The ssl module requires OpenSSL 1.1.1 or newer. (Contributed by Christian Heimes in PEP 644 [https://peps.python.org/pep-0644/] and bpo-43669 [https://bugs.python.org/issue?@action=redirect&bpo=43669].)

The ssl module has preliminary support for OpenSSL 3.0.0 and new option OP_IGNORE_UNEXPECTED_EOF. (Contributed by Christian Heimes in bpo-38820 [https://bugs.python.org/issue?@action=redirect&bpo=38820], bpo-43794 [https://bugs.python.org/issue?@action=redirect&bpo=43794], bpo-43788 [https://bugs.python.org/issue?@action=redirect&bpo=43788], bpo-43791 [https://bugs.python.org/issue?@action=redirect&bpo=43791], bpo-43799 [https://bugs.python.org/issue?@action=redirect&bpo=43799], bpo-43920 [https://bugs.python.org/issue?@action=redirect&bpo=43920], bpo-43789 [https://bugs.python.org/issue?@action=redirect&bpo=43789], and bpo-43811 [https://bugs.python.org/issue?@action=redirect&bpo=43811].)

Deprecated function and use of deprecated constants now result in a DeprecationWarning. ssl.SSLContext.options has OP_NO_SSLv2 and OP_NO_SSLv3 set by default and therefore cannot warn about setting the flag again. The deprecation section has a list of deprecated features. (Contributed by Christian Heimes in bpo-43880 [https://bugs.python.org/issue?@action=redirect&bpo=43880].)

The ssl module now has more secure default settings. Ciphers without forward secrecy or SHA-1 MAC are disabled by default. Security level 2 prohibits weak RSA, DH, and ECC keys with less than 112 bits of security. SSLContext defaults to minimum protocol version TLS 1.2. Settings are based on Hynek Schlawack’s research. (Contributed by Christian Heimes in bpo-43998 [https://bugs.python.org/issue?@action=redirect&bpo=43998].)

The deprecated protocols SSL 3.0, TLS 1.0, and TLS 1.1 are no longer officially supported. Python does not block them actively. However OpenSSL build options, distro configurations, vendor patches, and cipher suites may prevent a successful handshake.

Add a timeout parameter to the ssl.get_server_certificate() function. (Contributed by Zackery Spytz in bpo-31870 [https://bugs.python.org/issue?@action=redirect&bpo=31870].)

The ssl module uses heap-types and multi-phase initialization. (Contributed by Christian Heimes in bpo-42333 [https://bugs.python.org/issue?@action=redirect&bpo=42333].)

A new verify flag VERIFY_X509_PARTIAL_CHAIN has been added. (Contributed by l0x in bpo-40849 [https://bugs.python.org/issue?@action=redirect&bpo=40849].)

sqlite3

Add audit events for connect/handle(), enable_load_extension(), and load_extension(). (Contributed by Erlend E. Aasland in bpo-43762 [https://bugs.python.org/issue?@action=redirect&bpo=43762].)

sys

Add sys.orig_argv attribute: the list of the original command line arguments passed to the Python executable. (Contributed by Victor Stinner in bpo-23427 [https://bugs.python.org/issue?@action=redirect&bpo=23427].)

Add sys.stdlib_module_names, containing the list of the standard library module names. (Contributed by Victor Stinner in bpo-42955 [https://bugs.python.org/issue?@action=redirect&bpo=42955].)

_thread

_thread.interrupt_main() now takes an optional signal number to simulate (the default is still signal.SIGINT). (Contributed by Antoine Pitrou in bpo-43356 [https://bugs.python.org/issue?@action=redirect&bpo=43356].)

threading

Add threading.gettrace() and threading.getprofile() to retrieve the functions set by threading.settrace() and threading.setprofile() respectively. (Contributed by Mario Corchero in bpo-42251 [https://bugs.python.org/issue?@action=redirect&bpo=42251].)

Add threading.__excepthook__ to allow retrieving the original value of threading.excepthook() in case it is set to a broken or a different value. (Contributed by Mario Corchero in bpo-42308 [https://bugs.python.org/issue?@action=redirect&bpo=42308].)

traceback

The format_exception(), format_exception_only(), and print_exception() functions can now take an exception object as a positional-only argument. (Contributed by Zackery Spytz and Matthias Bussonnier in bpo-26389 [https://bugs.python.org/issue?@action=redirect&bpo=26389].)

types

Reintroduce the types.EllipsisType, types.NoneType and types.NotImplementedType classes, providing a new set of types readily interpretable by type checkers. (Contributed by Bas van Beek in bpo-41810 [https://bugs.python.org/issue?@action=redirect&bpo=41810].)

typing

For major changes, see New Features Related to Type Hints.

The behavior of typing.Literal was changed to conform with PEP 586 [https://peps.python.org/pep-0586/] and to match the behavior of static type checkers specified in the PEP.

Literal now de-duplicates parameters.

Equality comparisons between Literal objects are now order independent.

Literal comparisons now respect types. For example, Literal[0] == Literal[False] previously evaluated to True. It is now False. To support this change, the internally used type cache now supports differentiating types.

Literal objects will now raise a TypeError exception during equality comparisons if any of their parameters are not hashable. Note that declaring Literal with unhashable parameters will not throw an error:

>>> from typing import Literal
>>> Literal[{0}]
>>> Literal[{0}] == Literal[{False}]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'set'

(Contributed by Yurii Karabas in bpo-42345 [https://bugs.python.org/issue?@action=redirect&bpo=42345].)

Add new function typing.is_typeddict() to introspect if an annotation is a typing.TypedDict. (Contributed by Patrick Reader in bpo-41792 [https://bugs.python.org/issue?@action=redirect&bpo=41792].)

Subclasses of typing.Protocol which only have data variables declared will now raise a TypeError when checked with isinstance unless they are decorated with runtime_checkable(). Previously, these checks passed silently. Users should decorate their subclasses with the runtime_checkable() decorator if they want runtime protocols. (Contributed by Yurii Karabas in bpo-38908 [https://bugs.python.org/issue?@action=redirect&bpo=38908].)

Importing from the typing.io and typing.re submodules will now emit DeprecationWarning. These submodules have been deprecated since Python 3.8 and will be removed in a future version of Python. Anything belonging to those submodules should be imported directly from typing instead. (Contributed by Sebastian Rittau in bpo-38291 [https://bugs.python.org/issue?@action=redirect&bpo=38291].)

unittest

Add new method assertNoLogs() to complement the existing assertLogs(). (Contributed by Kit Yan Choi in bpo-39385 [https://bugs.python.org/issue?@action=redirect&bpo=39385].)

urllib.parse

Python versions earlier than Python 3.10 allowed using both ; and & as query parameter separators in urllib.parse.parse_qs() and urllib.parse.parse_qsl(). Due to security concerns, and to conform with newer W3C recommendations, this has been changed to allow only a single separator key, with & as the default. This change also affects cgi.parse() and cgi.parse_multipart() as they use the affected functions internally. For more details, please see their respective documentation. (Contributed by Adam Goldschmidt, Senthil Kumaran and Ken Jin in bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967].)

The presence of newline or tab characters in parts of a URL allows for some forms of attacks. Following the WHATWG specification that updates RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html], ASCII newline \n, \r and tab \t characters are stripped from the URL by the parser in urllib.parse preventing such attacks. The removal characters are controlled by a new module level variable urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE. (See gh-88048 [https://github.com/python/cpython/issues/88048])

xml

Add a LexicalHandler class to the xml.sax.handler module. (Contributed by Jonathan Gossage and Zackery Spytz in bpo-35018 [https://bugs.python.org/issue?@action=redirect&bpo=35018].)

zipimport

Add methods related to PEP 451 [https://peps.python.org/pep-0451/]: find_spec(), zipimport.zipimporter.create_module(), and zipimport.zipimporter.exec_module(). (Contributed by Brett Cannon in bpo-42131 [https://bugs.python.org/issue?@action=redirect&bpo=42131].)

Add invalidate_caches() method. (Contributed by Desmond Cheong in bpo-14678 [https://bugs.python.org/issue?@action=redirect&bpo=14678].)

Optimizations

Constructors str(), bytes() and bytearray() are now faster (around 30–40% for small objects). (Contributed by Serhiy Storchaka in bpo-41334 [https://bugs.python.org/issue?@action=redirect&bpo=41334].)

The runpy module now imports fewer modules. The python3 -m module-name command startup time is 1.4x faster in average. On Linux, python3 -I -m module-name imports 69 modules on Python 3.9, whereas it only imports 51 modules (-18) on Python 3.10. (Contributed by Victor Stinner in bpo-41006 [https://bugs.python.org/issue?@action=redirect&bpo=41006] and bpo-41718 [https://bugs.python.org/issue?@action=redirect&bpo=41718].)

The LOAD_ATTR instruction now uses new “per opcode cache” mechanism. It is about 36% faster now for regular attributes and 44% faster for slots. (Contributed by Pablo Galindo and Yury Selivanov in bpo-42093 [https://bugs.python.org/issue?@action=redirect&bpo=42093] and Guido van Rossum in bpo-42927 [https://bugs.python.org/issue?@action=redirect&bpo=42927], based on ideas implemented originally in PyPy and MicroPython.)

When building Python with --enable-optimizations now -fno-semantic-interposition is added to both the compile and link line. This speeds builds of the Python interpreter created with --enable-shared with gcc by up to 30%. See this article [https://developers.redhat.com/blog/2020/06/25/red-hat-enterprise-linux-8-2-brings-faster-python-3-8-run-speeds/] for more details. (Contributed by Victor Stinner and Pablo Galindo in bpo-38980 [https://bugs.python.org/issue?@action=redirect&bpo=38980].)

Use a new output buffer management code for bz2 / lzma / zlib modules, and add .readall() function to _compression.DecompressReader class. bz2 decompression is now 1.09x ~ 1.17x faster, lzma decompression 1.20x ~ 1.32x faster, GzipFile.read(-1) 1.11x ~ 1.18x faster. (Contributed by Ma Lin, reviewed by Gregory P. Smith, in bpo-41486 [https://bugs.python.org/issue?@action=redirect&bpo=41486])

When using stringized annotations, annotations dicts for functions are no longer created when the function is created. Instead, they are stored as a tuple of strings, and the function object lazily converts this into the annotations dict on demand. This optimization cuts the CPU time needed to define an annotated function by half. (Contributed by Yurii Karabas and Inada Naoki in bpo-42202 [https://bugs.python.org/issue?@action=redirect&bpo=42202].)

Substring search functions such as str1 in str2 and str2.find(str1) now sometimes use Crochemore & Perrin’s “Two-Way” string searching algorithm to avoid quadratic behavior on long strings. (Contributed by Dennis Sweeney in bpo-41972 [https://bugs.python.org/issue?@action=redirect&bpo=41972])

Add micro-optimizations to _PyType_Lookup() to improve type attribute cache lookup performance in the common case of cache hits. This makes the interpreter 1.04 times faster on average. (Contributed by Dino Viehland in bpo-43452 [https://bugs.python.org/issue?@action=redirect&bpo=43452].)

The following built-in functions now support the faster PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention: map(), filter(), reversed(), bool() and float(). (Contributed by Donghee Na and Jeroen Demeyer in bpo-43575 [https://bugs.python.org/issue?@action=redirect&bpo=43575], bpo-43287 [https://bugs.python.org/issue?@action=redirect&bpo=43287], bpo-41922 [https://bugs.python.org/issue?@action=redirect&bpo=41922], bpo-41873 [https://bugs.python.org/issue?@action=redirect&bpo=41873] and bpo-41870 [https://bugs.python.org/issue?@action=redirect&bpo=41870].)

BZ2File performance is improved by removing internal RLock. This makes BZ2File thread unsafe in the face of multiple simultaneous readers or writers, just like its equivalent classes in gzip and lzma have always been. (Contributed by Inada Naoki in bpo-43785 [https://bugs.python.org/issue?@action=redirect&bpo=43785].)

Deprecated

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). Starting in this release, a deprecation warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In future releases it will be changed to syntax warning, and finally to syntax error. (Contributed by Serhiy Storchaka in bpo-43833 [https://bugs.python.org/issue?@action=redirect&bpo=43833].)

Starting in this release, there will be a concerted effort to begin cleaning up old import semantics that were kept for Python 2.7 compatibility. Specifically, find_loader()/find_module() (superseded by find_spec()), load_module() (superseded by exec_module()), module_repr() (which the import system takes care of for you), the __package__ attribute (superseded by __spec__.parent), the __loader__ attribute (superseded by __spec__.loader), and the __cached__ attribute (superseded by __spec__.cached) will slowly be removed (as well as other classes and methods in importlib). ImportWarning and/or DeprecationWarning will be raised as appropriate to help identify code which needs updating during this transition.

The entire distutils namespace is deprecated, to be removed in Python 3.12. Refer to the module changes section for more information.

Non-integer arguments to random.randrange() are deprecated. The ValueError is deprecated in favor of a TypeError. (Contributed by Serhiy Storchaka and Raymond Hettinger in bpo-37319 [https://bugs.python.org/issue?@action=redirect&bpo=37319].)

The various load_module() methods of importlib have been documented as deprecated since Python 3.6, but will now also trigger a DeprecationWarning. Use exec_module() instead. (Contributed by Brett Cannon in bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131].)

zimport.zipimporter.load_module() has been deprecated in preference for exec_module(). (Contributed by Brett Cannon in bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131].)

The use of load_module() by the import system now triggers an ImportWarning as exec_module() is preferred. (Contributed by Brett Cannon in bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131].)

The use of importlib.abc.MetaPathFinder.find_module() and importlib.abc.PathEntryFinder.find_module() by the import system now trigger an ImportWarning as importlib.abc.MetaPathFinder.find_spec() and importlib.abc.PathEntryFinder.find_spec() are preferred, respectively. You can use importlib.util.spec_from_loader() to help in porting. (Contributed by Brett Cannon in bpo-42134 [https://bugs.python.org/issue?@action=redirect&bpo=42134].)

The use of importlib.abc.PathEntryFinder.find_loader() by the import system now triggers an ImportWarning as importlib.abc.PathEntryFinder.find_spec() is preferred. You can use importlib.util.spec_from_loader() to help in porting. (Contributed by Brett Cannon in bpo-43672 [https://bugs.python.org/issue?@action=redirect&bpo=43672].)

The various implementations of importlib.abc.MetaPathFinder.find_module() ( importlib.machinery.BuiltinImporter.find_module(), importlib.machinery.FrozenImporter.find_module(), importlib.machinery.WindowsRegistryFinder.find_module(), importlib.machinery.PathFinder.find_module(), importlib.abc.MetaPathFinder.find_module() ), importlib.abc.PathEntryFinder.find_module() ( importlib.machinery.FileFinder.find_module() ), and importlib.abc.PathEntryFinder.find_loader() ( importlib.machinery.FileFinder.find_loader() ) now raise DeprecationWarning and are slated for removal in Python 3.12 (previously they were documented as deprecated in Python 3.4). (Contributed by Brett Cannon in bpo-42135 [https://bugs.python.org/issue?@action=redirect&bpo=42135].)

importlib.abc.Finder is deprecated (including its sole method, find_module()). Both importlib.abc.MetaPathFinder and importlib.abc.PathEntryFinder no longer inherit from the class. Users should inherit from one of these two classes as appropriate instead. (Contributed by Brett Cannon in bpo-42135 [https://bugs.python.org/issue?@action=redirect&bpo=42135].)

The deprecations of imp, importlib.find_loader(), importlib.util.set_package_wrapper(), importlib.util.set_loader_wrapper(), importlib.util.module_for_loader(), pkgutil.ImpImporter, and pkgutil.ImpLoader have all been updated to list Python 3.12 as the slated version of removal (they began raising DeprecationWarning in previous versions of Python). (Contributed by Brett Cannon in bpo-43720 [https://bugs.python.org/issue?@action=redirect&bpo=43720].)

The import system now uses the __spec__ attribute on modules before falling back on module_repr() for a module’s __repr__() method. Removal of the use of module_repr() is scheduled for Python 3.12. (Contributed by Brett Cannon in bpo-42137 [https://bugs.python.org/issue?@action=redirect&bpo=42137].)

importlib.abc.Loader.module_repr(), importlib.machinery.FrozenLoader.module_repr(), and importlib.machinery.BuiltinLoader.module_repr() are deprecated and slated for removal in Python 3.12. (Contributed by Brett Cannon in bpo-42136 [https://bugs.python.org/issue?@action=redirect&bpo=42136].)

sqlite3.OptimizedUnicode has been undocumented and obsolete since Python 3.3, when it was made an alias to str. It is now deprecated, scheduled for removal in Python 3.12. (Contributed by Erlend E. Aasland in bpo-42264 [https://bugs.python.org/issue?@action=redirect&bpo=42264].)

The undocumented built-in function sqlite3.enable_shared_cache is now deprecated, scheduled for removal in Python 3.12. Its use is strongly discouraged by the SQLite3 documentation. See the SQLite3 docs [https://sqlite.org/c3ref/enable_shared_cache.html] for more details. If a shared cache must be used, open the database in URI mode using the cache=shared query parameter. (Contributed by Erlend E. Aasland in bpo-24464 [https://bugs.python.org/issue?@action=redirect&bpo=24464].)

The following threading methods are now deprecated:

threading.currentThread => threading.current_thread()

threading.activeCount => threading.active_count()

threading.Condition.notifyAll => threading.Condition.notify_all()

threading.Event.isSet => threading.Event.is_set()

threading.Thread.setName => threading.Thread.name

threading.thread.getName => threading.Thread.name

threading.Thread.isDaemon => threading.Thread.daemon

threading.Thread.setDaemon => threading.Thread.daemon

(Contributed by Jelle Zijlstra in gh-87889 [https://github.com/python/cpython/issues/87889].)

pathlib.Path.link_to() is deprecated and slated for removal in Python 3.12. Use pathlib.Path.hardlink_to() instead. (Contributed by Barney Gale in bpo-39950 [https://bugs.python.org/issue?@action=redirect&bpo=39950].)

cgi.log() is deprecated and slated for removal in Python 3.12. (Contributed by Inada Naoki in bpo-41139 [https://bugs.python.org/issue?@action=redirect&bpo=41139].)

The following ssl features have been deprecated since Python 3.6, Python 3.7, or OpenSSL 1.1.0 and will be removed in 3.11:

OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_TLSv1, OP_NO_TLSv1_1, OP_NO_TLSv1_2, and OP_NO_TLSv1_3 are replaced by minimum_version and maximum_version.

PROTOCOL_SSLv2, PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1, PROTOCOL_TLSv1_1, PROTOCOL_TLSv1_2, and PROTOCOL_TLS are deprecated in favor of PROTOCOL_TLS_CLIENT and PROTOCOL_TLS_SERVER

wrap_socket() is replaced by ssl.SSLContext.wrap_socket()

match_hostname()

RAND_pseudo_bytes(), RAND_egd()

NPN features like ssl.SSLSocket.selected_npn_protocol() and ssl.SSLContext.set_npn_protocols() are replaced by ALPN.

The threading debug (PYTHONTHREADDEBUG environment variable) is deprecated in Python 3.10 and will be removed in Python 3.12. This feature requires a debug build of Python. (Contributed by Victor Stinner in bpo-44584 [https://bugs.python.org/issue?@action=redirect&bpo=44584].)

Importing from the typing.io and typing.re submodules will now emit DeprecationWarning. These submodules will be removed in a future version of Python. Anything belonging to these submodules should be imported directly from typing instead. (Contributed by Sebastian Rittau in bpo-38291 [https://bugs.python.org/issue?@action=redirect&bpo=38291].)

Removed

Removed special methods __int__, __float__, __floordiv__, __mod__, __divmod__, __rfloordiv__, __rmod__ and __rdivmod__ of the complex class. They always raised a TypeError. (Contributed by Serhiy Storchaka in bpo-41974 [https://bugs.python.org/issue?@action=redirect&bpo=41974].)

The ParserBase.error() method from the private and undocumented _markupbase module has been removed. html.parser.HTMLParser is the only subclass of ParserBase and its error() implementation was already removed in Python 3.5. (Contributed by Berker Peksag in bpo-31844 [https://bugs.python.org/issue?@action=redirect&bpo=31844].)

Removed the unicodedata.ucnhash_CAPI attribute which was an internal PyCapsule object. The related private _PyUnicode_Name_CAPI structure was moved to the internal C API. (Contributed by Victor Stinner in bpo-42157 [https://bugs.python.org/issue?@action=redirect&bpo=42157].)

Removed the parser module, which was deprecated in 3.9 due to the switch to the new PEG parser, as well as all the C source and header files that were only being used by the old parser, including node.h, parser.h, graminit.h and grammar.h.

Removed the Public C API functions PyParser_SimpleParseStringFlags, PyParser_SimpleParseStringFlagsFilename, PyParser_SimpleParseFileFlags and PyNode_Compile that were deprecated in 3.9 due to the switch to the new PEG parser.

Removed the formatter module, which was deprecated in Python 3.4. It is somewhat obsolete, little used, and not tested. It was originally scheduled to be removed in Python 3.6, but such removals were delayed until after Python 2.7 EOL. Existing users should copy whatever classes they use into their code. (Contributed by Donghee Na and Terry J. Reedy in bpo-42299 [https://bugs.python.org/issue?@action=redirect&bpo=42299].)

Removed the PyModule_GetWarningsModule() function that was useless now due to the _warnings module was converted to a builtin module in 2.6. (Contributed by Hai Shi in bpo-42599 [https://bugs.python.org/issue?@action=redirect&bpo=42599].)

Remove deprecated aliases to Collections 추상 베이스 클래스 from the collections module. (Contributed by Victor Stinner in bpo-37324 [https://bugs.python.org/issue?@action=redirect&bpo=37324].)

The loop parameter has been removed from most of asyncio‘s high-level API following deprecation in Python 3.8. The motivation behind this change is multifold:

This simplifies the high-level API.

The functions in the high-level API have been implicitly getting the current thread’s running event loop since Python 3.7. There isn’t a need to pass the event loop to the API in most normal use cases.

Event loop passing is error-prone especially when dealing with loops running in different threads.

Note that the low-level API will still accept loop. See Changes in the Python API for examples of how to replace existing code.

(Contributed by Yurii Karabas, Andrew Svetlov, Yury Selivanov and Kyle Stanley in bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392].)

Porting to Python 3.10

This section lists previously described changes and other bugfixes that may require changes to your code.

Changes in the Python syntax

Deprecation warning is now emitted when compiling previously valid syntax if the numeric literal is immediately followed by a keyword (like in 0in x). In future releases it will be changed to syntax warning, and finally to a syntax error. To get rid of the warning and make the code compatible with future releases just add a space between the numeric literal and the following keyword. (Contributed by Serhiy Storchaka in bpo-43833 [https://bugs.python.org/issue?@action=redirect&bpo=43833].)

Changes in the Python API

The etype parameters of the format_exception(), format_exception_only(), and print_exception() functions in the traceback module have been renamed to exc. (Contributed by Zackery Spytz and Matthias Bussonnier in bpo-26389 [https://bugs.python.org/issue?@action=redirect&bpo=26389].)

atexit: At Python exit, if a callback registered with atexit.register() fails, its exception is now logged. Previously, only some exceptions were logged, and the last exception was always silently ignored. (Contributed by Victor Stinner in bpo-42639 [https://bugs.python.org/issue?@action=redirect&bpo=42639].)

collections.abc.Callable generic now flattens type parameters, similar to what typing.Callable currently does. This means that collections.abc.Callable[[int, str], str] will have __args__ of (int, str, str); previously this was ([int, str], str). Code which accesses the arguments via typing.get_args() or __args__ need to account for this change. Furthermore, TypeError may be raised for invalid forms of parameterizing collections.abc.Callable which may have passed silently in Python 3.9. (Contributed by Ken Jin in bpo-42195 [https://bugs.python.org/issue?@action=redirect&bpo=42195].)

socket.htons() and socket.ntohs() now raise OverflowError instead of DeprecationWarning if the given parameter will not fit in a 16-bit unsigned integer. (Contributed by Erlend E. Aasland in bpo-42393 [https://bugs.python.org/issue?@action=redirect&bpo=42393].)

The loop parameter has been removed from most of asyncio‘s high-level API following deprecation in Python 3.8.

A coroutine that currently looks like this:

async def foo(loop):
    await asyncio.sleep(1, loop=loop)

Should be replaced with this:

async def foo():
    await asyncio.sleep(1)

If foo() was specifically designed not to run in the current thread’s running event loop (e.g. running in another thread’s event loop), consider using asyncio.run_coroutine_threadsafe() instead.

(Contributed by Yurii Karabas, Andrew Svetlov, Yury Selivanov and Kyle Stanley in bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392].)

The types.FunctionType constructor now inherits the current builtins if the globals dictionary has no "__builtins__" key, rather than using {"None": None} as builtins: same behavior as eval() and exec() functions. Defining a function with def function(...): ... in Python is not affected, globals cannot be overridden with this syntax: it also inherits the current builtins. (Contributed by Victor Stinner in bpo-42990 [https://bugs.python.org/issue?@action=redirect&bpo=42990].)

Changes in the C API

The C API functions PyParser_SimpleParseStringFlags, PyParser_SimpleParseStringFlagsFilename, PyParser_SimpleParseFileFlags, PyNode_Compile and the type used by these functions, struct _node, were removed due to the switch to the new PEG parser.

Source should be now be compiled directly to a code object using, for example, Py_CompileString(). The resulting code object can then be evaluated using, for example, PyEval_EvalCode().

Specifically:

A call to PyParser_SimpleParseStringFlags followed by PyNode_Compile can be replaced by calling Py_CompileString().

There is no direct replacement for PyParser_SimpleParseFileFlags. To compile code from a FILE * argument, you will need to read the file in C and pass the resulting buffer to Py_CompileString().

To compile a file given a char * filename, explicitly open the file, read it and compile the result. One way to do this is using the io module with PyImport_ImportModule(), PyObject_CallMethod(), PyBytes_AsString() and Py_CompileString(), as sketched below. (Declarations and error handling are omitted.)

io_module = Import_ImportModule("io");
fileobject = PyObject_CallMethod(io_module, "open", "ss", filename, "rb");
source_bytes_object = PyObject_CallMethod(fileobject, "read", "");
result = PyObject_CallMethod(fileobject, "close", "");
source_buf = PyBytes_AsString(source_bytes_object);
code = Py_CompileString(source_buf, filename, Py_file_input);

For FrameObject objects, the f_lasti member now represents a wordcode offset instead of a simple offset into the bytecode string. This means that this number needs to be multiplied by 2 to be used with APIs that expect a byte offset instead (like PyCode_Addr2Line() for example). Notice as well that the f_lasti member of FrameObject objects is not considered stable: please use PyFrame_GetLineNumber() instead.

CPython bytecode changes

The MAKE_FUNCTION instruction now accepts either a dict or a tuple of strings as the function’s annotations. (Contributed by Yurii Karabas and Inada Naoki in bpo-42202 [https://bugs.python.org/issue?@action=redirect&bpo=42202].)

Build Changes

PEP 644 [https://peps.python.org/pep-0644/]: Python now requires OpenSSL 1.1.1 or newer. OpenSSL 1.0.2 is no longer supported. (Contributed by Christian Heimes in bpo-43669 [https://bugs.python.org/issue?@action=redirect&bpo=43669].)

The C99 functions snprintf() and vsnprintf() are now required to build Python. (Contributed by Victor Stinner in bpo-36020 [https://bugs.python.org/issue?@action=redirect&bpo=36020].)

sqlite3 requires SQLite 3.7.15 or higher. (Contributed by Sergey Fedoseev and Erlend E. Aasland in bpo-40744 [https://bugs.python.org/issue?@action=redirect&bpo=40744] and bpo-40810 [https://bugs.python.org/issue?@action=redirect&bpo=40810].)

The atexit module must now always be built as a built-in module. (Contributed by Victor Stinner in bpo-42639 [https://bugs.python.org/issue?@action=redirect&bpo=42639].)

Add --disable-test-modules option to the configure script: don’t build nor install test modules. (Contributed by Xavier de Gaye, Thomas Petazzoni and Peixing Xin in bpo-27640 [https://bugs.python.org/issue?@action=redirect&bpo=27640].)

Add --with-wheel-pkg-dir=PATH option to the ./configure script. If specified, the ensurepip module looks for setuptools and pip wheel packages in this directory: if both are present, these wheel packages are used instead of ensurepip bundled wheel packages.

Some Linux distribution packaging policies recommend against bundling dependencies. For example, Fedora installs wheel packages in the /usr/share/python-wheels/ directory and don’t install the ensurepip._bundled package.

(Contributed by Victor Stinner in bpo-42856 [https://bugs.python.org/issue?@action=redirect&bpo=42856].)

Add a new configure --without-static-libpython option to not build the libpythonMAJOR.MINOR.a static library and not install the python.o object file.

(Contributed by Victor Stinner in bpo-43103 [https://bugs.python.org/issue?@action=redirect&bpo=43103].)

The configure script now uses the pkg-config utility, if available, to detect the location of Tcl/Tk headers and libraries. As before, those locations can be explicitly specified with the --with-tcltk-includes and --with-tcltk-libs configuration options. (Contributed by Manolis Stamatogiannakis in bpo-42603 [https://bugs.python.org/issue?@action=redirect&bpo=42603].)

Add --with-openssl-rpath option to configure script. The option simplifies building Python with a custom OpenSSL installation, e.g. ./configure --with-openssl=/path/to/openssl --with-openssl-rpath=auto. (Contributed by Christian Heimes in bpo-43466 [https://bugs.python.org/issue?@action=redirect&bpo=43466].)

C API Changes

PEP 652: Maintaining the Stable ABI

The Stable ABI (Application Binary Interface) for extension modules or embedding Python is now explicitly defined. C API Stability describes C API and ABI stability guarantees along with best practices for using the Stable ABI.

(Contributed by Petr Viktorin in PEP 652 [https://peps.python.org/pep-0652/] and bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795].)

New Features

The result of PyNumber_Index() now always has exact type int. Previously, the result could have been an instance of a subclass of int. (Contributed by Serhiy Storchaka in bpo-40792 [https://bugs.python.org/issue?@action=redirect&bpo=40792].)

Add a new orig_argv member to the PyConfig structure: the list of the original command line arguments passed to the Python executable. (Contributed by Victor Stinner in bpo-23427 [https://bugs.python.org/issue?@action=redirect&bpo=23427].)

The PyDateTime_DATE_GET_TZINFO() and PyDateTime_TIME_GET_TZINFO() macros have been added for accessing the tzinfo attributes of datetime.datetime and datetime.time objects. (Contributed by Zackery Spytz in bpo-30155 [https://bugs.python.org/issue?@action=redirect&bpo=30155].)

Add a PyCodec_Unregister() function to unregister a codec search function. (Contributed by Hai Shi in bpo-41842 [https://bugs.python.org/issue?@action=redirect&bpo=41842].)

The PyIter_Send() function was added to allow sending value into iterator without raising StopIteration exception. (Contributed by Vladimir Matveev in bpo-41756 [https://bugs.python.org/issue?@action=redirect&bpo=41756].)

Add PyUnicode_AsUTF8AndSize() to the limited C API. (Contributed by Alex Gaynor in bpo-41784 [https://bugs.python.org/issue?@action=redirect&bpo=41784].)

Add PyModule_AddObjectRef() function: similar to PyModule_AddObject() but don’t steal a reference to the value on success. (Contributed by Victor Stinner in bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741].)

Add Py_NewRef() and Py_XNewRef() functions to increment the reference count of an object and return the object. (Contributed by Victor Stinner in bpo-42262 [https://bugs.python.org/issue?@action=redirect&bpo=42262].)

The PyType_FromSpecWithBases() and PyType_FromModuleAndSpec() functions now accept a single class as the bases argument. (Contributed by Serhiy Storchaka in bpo-42423 [https://bugs.python.org/issue?@action=redirect&bpo=42423].)

The PyType_FromModuleAndSpec() function now accepts NULL tp_doc slot. (Contributed by Hai Shi in bpo-41832 [https://bugs.python.org/issue?@action=redirect&bpo=41832].)

The PyType_GetSlot() function can accept static types. (Contributed by Hai Shi and Petr Viktorin in bpo-41073 [https://bugs.python.org/issue?@action=redirect&bpo=41073].)

Add a new PySet_CheckExact() function to the C-API to check if an object is an instance of set but not an instance of a subtype. (Contributed by Pablo Galindo in bpo-43277 [https://bugs.python.org/issue?@action=redirect&bpo=43277].)

Add PyErr_SetInterruptEx() which allows passing a signal number to simulate. (Contributed by Antoine Pitrou in bpo-43356 [https://bugs.python.org/issue?@action=redirect&bpo=43356].)

The limited C API is now supported if Python is built in debug mode (if the Py_DEBUG macro is defined). In the limited C API, the Py_INCREF() and Py_DECREF() functions are now implemented as opaque function calls, rather than accessing directly the PyObject.ob_refcnt member, if Python is built in debug mode and the Py_LIMITED_API macro targets Python 3.10 or newer. It became possible to support the limited C API in debug mode because the PyObject structure is the same in release and debug mode since Python 3.8 (see bpo-36465 [https://bugs.python.org/issue?@action=redirect&bpo=36465]).

The limited C API is still not supported in the --with-trace-refs special build (Py_TRACE_REFS macro). (Contributed by Victor Stinner in bpo-43688 [https://bugs.python.org/issue?@action=redirect&bpo=43688].)

Add the Py_Is(x, y) function to test if the x object is the y object, the same as x is y in Python. Add also the Py_IsNone(), Py_IsTrue(), Py_IsFalse() functions to test if an object is, respectively, the None singleton, the True singleton or the False singleton. (Contributed by Victor Stinner in bpo-43753 [https://bugs.python.org/issue?@action=redirect&bpo=43753].)

Add new functions to control the garbage collector from C code: PyGC_Enable(), PyGC_Disable(), PyGC_IsEnabled(). These functions allow to activate, deactivate and query the state of the garbage collector from C code without having to import the gc module.

Add a new Py_TPFLAGS_DISALLOW_INSTANTIATION type flag to disallow creating type instances. (Contributed by Victor Stinner in bpo-43916 [https://bugs.python.org/issue?@action=redirect&bpo=43916].)

Add a new Py_TPFLAGS_IMMUTABLETYPE type flag for creating immutable type objects: type attributes cannot be set nor deleted. (Contributed by Victor Stinner and Erlend E. Aasland in bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908].)

Porting to Python 3.10

The PY_SSIZE_T_CLEAN macro must now be defined to use PyArg_ParseTuple() and Py_BuildValue() formats which use #: es#, et#, s#, u#, y#, z#, U# and Z#. See 인자 구문 분석과 값 구축 and PEP 353 [https://peps.python.org/pep-0353/]. (Contributed by Victor Stinner in bpo-40943 [https://bugs.python.org/issue?@action=redirect&bpo=40943].)

Since Py_REFCNT() is changed to the inline static function, Py_REFCNT(obj) = new_refcnt must be replaced with Py_SET_REFCNT(obj, new_refcnt): see Py_SET_REFCNT() (available since Python 3.9). For backward compatibility, this macro can be used:

#if PY_VERSION_HEX < 0x030900A4
#  define Py_SET_REFCNT(obj, refcnt) ((Py_REFCNT(obj) = (refcnt)), (void)0)
#endif

(Contributed by Victor Stinner in bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573].)

Calling PyDict_GetItem() without GIL held had been allowed for historical reason. It is no longer allowed. (Contributed by Victor Stinner in bpo-40839 [https://bugs.python.org/issue?@action=redirect&bpo=40839].)

PyUnicode_FromUnicode(NULL, size) and PyUnicode_FromStringAndSize(NULL, size) raise DeprecationWarning now. Use PyUnicode_New() to allocate Unicode object without initial data. (Contributed by Inada Naoki in bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346].)

The private _PyUnicode_Name_CAPI structure of the PyCapsule API unicodedata.ucnhash_CAPI has been moved to the internal C API. (Contributed by Victor Stinner in bpo-42157 [https://bugs.python.org/issue?@action=redirect&bpo=42157].)

Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix(), Py_GetProgramFullPath(), Py_GetPythonHome() and Py_GetProgramName() functions now return NULL if called before Py_Initialize() (before Python is initialized). Use the new 파이썬 초기화 구성 API to get the Python Path Configuration. (Contributed by Victor Stinner in bpo-42260 [https://bugs.python.org/issue?@action=redirect&bpo=42260].)

PyList_SET_ITEM(), PyTuple_SET_ITEM() and PyCell_SET() macros can no longer be used as l-value or r-value. For example, x = PyList_SET_ITEM(a, b, c) and PyList_SET_ITEM(a, b, c) = x now fail with a compiler error. It prevents bugs like if (PyList_SET_ITEM (a, b, c) < 0) ... test. (Contributed by Zackery Spytz and Victor Stinner in bpo-30459 [https://bugs.python.org/issue?@action=redirect&bpo=30459].)

The non-limited API files odictobject.h, parser_interface.h, picklebufobject.h, pyarena.h, pyctype.h, pydebug.h, pyfpe.h, and pytime.h have been moved to the Include/cpython directory. These files must not be included directly, as they are already included in Python.h; see 인클루드 파일. If they have been included directly, consider including Python.h instead. (Contributed by Nicholas Sim in bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134].)

Use the Py_TPFLAGS_IMMUTABLETYPE type flag to create immutable type objects. Do not rely on Py_TPFLAGS_HEAPTYPE to decide if a type object is mutable or not; check if Py_TPFLAGS_IMMUTABLETYPE is set instead. (Contributed by Victor Stinner and Erlend E. Aasland in bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908].)

The undocumented function Py_FrozenMain has been removed from the limited API. The function is mainly useful for custom builds of Python. (Contributed by Petr Viktorin in bpo-26241 [https://bugs.python.org/issue?@action=redirect&bpo=26241].)

Deprecated

The PyUnicode_InternImmortal() function is now deprecated and will be removed in Python 3.12: use PyUnicode_InternInPlace() instead. (Contributed by Victor Stinner in bpo-41692 [https://bugs.python.org/issue?@action=redirect&bpo=41692].)

Removed

Removed Py_UNICODE_str* functions manipulating Py_UNICODE* strings. (Contributed by Inada Naoki in bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123].)

Py_UNICODE_strlen: use PyUnicode_GetLength() or PyUnicode_GET_LENGTH

Py_UNICODE_strcat: use PyUnicode_CopyCharacters() or PyUnicode_FromFormat()

Py_UNICODE_strcpy, Py_UNICODE_strncpy: use PyUnicode_CopyCharacters() or PyUnicode_Substring()

Py_UNICODE_strcmp: use PyUnicode_Compare()

Py_UNICODE_strncmp: use PyUnicode_Tailmatch()

Py_UNICODE_strchr, Py_UNICODE_strrchr: use PyUnicode_FindChar()

Removed PyUnicode_GetMax(). Please migrate to new (PEP 393 [https://peps.python.org/pep-0393/]) APIs. (Contributed by Inada Naoki in bpo-41103 [https://bugs.python.org/issue?@action=redirect&bpo=41103].)

Removed PyLong_FromUnicode(). Please migrate to PyLong_FromUnicodeObject(). (Contributed by Inada Naoki in bpo-41103 [https://bugs.python.org/issue?@action=redirect&bpo=41103].)

Removed PyUnicode_AsUnicodeCopy(). Please use PyUnicode_AsUCS4Copy() or PyUnicode_AsWideCharString() (Contributed by Inada Naoki in bpo-41103 [https://bugs.python.org/issue?@action=redirect&bpo=41103].)

Removed _Py_CheckRecursionLimit variable: it has been replaced by ceval.recursion_limit of the PyInterpreterState structure. (Contributed by Victor Stinner in bpo-41834 [https://bugs.python.org/issue?@action=redirect&bpo=41834].)

Removed undocumented macros Py_ALLOW_RECURSION and Py_END_ALLOW_RECURSION and the recursion_critical field of the PyInterpreterState structure. (Contributed by Serhiy Storchaka in bpo-41936 [https://bugs.python.org/issue?@action=redirect&bpo=41936].)

Removed the undocumented PyOS_InitInterrupts() function. Initializing Python already implicitly installs signal handlers: see PyConfig.install_signal_handlers. (Contributed by Victor Stinner in bpo-41713 [https://bugs.python.org/issue?@action=redirect&bpo=41713].)

Remove the PyAST_Validate() function. It is no longer possible to build a AST object (mod_ty type) with the public C API. The function was already excluded from the limited C API (PEP 384 [https://peps.python.org/pep-0384/]). (Contributed by Victor Stinner in bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244].)

Remove the symtable.h header file and the undocumented functions:

PyST_GetScope()

PySymtable_Build()

PySymtable_BuildObject()

PySymtable_Free()

Py_SymtableString()

Py_SymtableStringObject()

The Py_SymtableString() function was part the stable ABI by mistake but it could not be used, because the symtable.h header file was excluded from the limited C API.

Use Python symtable module instead. (Contributed by Victor Stinner in bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244].)

Remove PyOS_ReadlineFunctionPointer() from the limited C API headers and from python3.dll, the library that provides the stable ABI on Windows. Since the function takes a FILE* argument, its ABI stability cannot be guaranteed. (Contributed by Petr Viktorin in bpo-43868 [https://bugs.python.org/issue?@action=redirect&bpo=43868].)

Remove ast.h, asdl.h, and Python-ast.h header files. These functions were undocumented and excluded from the limited C API. Most names defined by these header files were not prefixed by Py and so could create names conflicts. For example, Python-ast.h defined a Yield macro which was conflict with the Yield name used by the Windows <winbase.h> header. Use the Python ast module instead. (Contributed by Victor Stinner in bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244].)

Remove the compiler and parser functions using struct _mod type, because the public AST C API was removed:

PyAST_Compile()

PyAST_CompileEx()

PyAST_CompileObject()

PyFuture_FromAST()

PyFuture_FromASTObject()

PyParser_ASTFromFile()

PyParser_ASTFromFileObject()

PyParser_ASTFromFilename()

PyParser_ASTFromString()

PyParser_ASTFromStringObject()

These functions were undocumented and excluded from the limited C API. (Contributed by Victor Stinner in bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244].)

Remove the pyarena.h header file with functions:

PyArena_New()

PyArena_Free()

PyArena_Malloc()

PyArena_AddPyObject()

These functions were undocumented, excluded from the limited C API, and were only used internally by the compiler. (Contributed by Victor Stinner in bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244].)

The PyThreadState.use_tracing member has been removed to optimize Python. (Contributed by Mark Shannon in bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760].)

Notable security feature in 3.10.7

Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735]. This limit can be configured or disabled by environment variable, command line flag, or sys APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.

Notable security feature in 3.10.8

The deprecated mailcap module now refuses to inject unsafe text (filenames, MIME types, parameters) into shell commands. Instead of using such text, it will warn and act as if a match was not found (or for test commands, as if the test failed). (Contributed by Petr Viktorin in gh-98966 [https://github.com/python/cpython/issues/98966].)

Notable changes in 3.10.12

tarfile

The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details. In Python 3.12, use without the filter argument will show a DeprecationWarning. In Python 3.14, the default will switch to 'data'. (Contributed by Petr Viktorin in PEP 706 [https://peps.python.org/pep-0706/].)

파이썬 3.9의 새로운 기능

편집자:

Łukasz Langa

This article explains the new features in Python 3.9, compared to 3.8. Python 3.9 was released on October 5, 2020. For full details, see the changelog.

더 보기

PEP 596 [https://peps.python.org/pep-0596/] - 파이썬 3.9 출시 일정

요약 – 배포 주요 사항

새로운 문법 기능:

PEP 584 [https://peps.python.org/pep-0584/], 병합(union) 연산자가 dict에 추가되었습니다.

PEP 585 [https://peps.python.org/pep-0585/], 표준 컬렉션의 형 힌트 제네릭;

PEP 614 [https://peps.python.org/pep-0614/], 데코레이터에 대한 완화된 문법 제한.

새로운 내장 기능:

PEP 616 [https://peps.python.org/pep-0616/], 접두사와 접미사를 제거하는 문자열 메서드.

표준 라이브러리의 새로운 기능:

PEP 593 [https://peps.python.org/pep-0593/], 유연한 함수와 변수 어노테이션;

경쟁과 시그널 없이 프로세스 관리를 허용하는 os.pidfd_open()이 추가되었습니다.

인터프리터 개선:

PEP 573 [https://peps.python.org/pep-0573/], C 확장형의 메서드에서 모듈 상태에 빠르게 액세스하기;

PEP 617 [https://peps.python.org/pep-0617/], CPython은 이제 PEG를 기반으로 하는 새로운 구문 분석기를 사용합니다;

많은 파이썬 내장(range, tuple, set, frozenset, list, dict)이 이제 PEP 590 [https://peps.python.org/pep-0590/] 벡터콜을 사용하여 빨라졌습니다;

가비지 수거는 부활한 객체에서 블록 되지 않습니다;

a number of Python modules (_abc, audioop, _bz2, _codecs, _contextvars, _crypt, _functools, _json, _locale, math, operator, resource, time, _weakref) now use multiphase initialization as defined by PEP 489;

a number of standard library modules (audioop, ast, grp, _hashlib, pwd, _posixsubprocess, random, select, struct, termios, zlib) are now using the stable ABI defined by PEP 384.

새로운 라이브러리 모듈:

PEP 615 [https://peps.python.org/pep-0615/], IANA 시간대 데이터베이스는 이제 zoneinfo 모듈을 통해 표준 라이브러리에 있습니다;

이제 새로운 graphlib 모듈에서 그래프의 위상 정렬(topological sort) 구현이 제공됩니다.

릴리스 프로세스 변경:

PEP 602 [https://peps.python.org/pep-0602/], CPython은 연간 릴리스 주기를 채택합니다.

여러분의 코드에서 DeprecationWarning을 확인해야합니다

파이썬 2.7이 여전히 지원될 때, 파이썬 2.7과의 과거 호환성을 위해 파이썬 3의 많은 기능이 유지되었습니다. 파이썬 2.7 지원이 종료되면서, 이러한 이전 버전과의 호환성 계층이 제거되었거나, 곧 제거될 예정입니다. 그들 대부분은 몇 년 동안 DeprecationWarning 경고를 내보냈습니다. 예를 들어, collections.abc.Mapping 대신 collections.Mapping을 사용하면 2012년에 배포된 파이썬 3.3 이후 DeprecationWarning을 내보냅니다.

-W default 명령 줄 옵션으로 응용 프로그램을 테스트하여 DeprecationWarning과 PendingDeprecationWarning 을 보십시오. 또는 -W error로 아예 에러로 취급하십시오. 경고 필터를 사용하면 제삼자 코드의 경고를 무시할 수 있습니다.

파이썬 3.9는 파이썬 프로젝트 지원 담당자가 파이썬 2 지원 제거를 구성하고 파이썬 3.9에 대한 지원을 추가할 수 있도록 더 많은 시간을 제공하기 위한, 파이썬 2 과거 호환성 계층을 제공하는 마지막 버전입니다.

collections 모듈의 추상 베이스 클래스에 대한 별칭(collections.abc.Mapping에 대한 collections.Mapping 별칭과 같은)은 이전 버전과의 호환성을 위해 마지막 배포 하나에서 유지됩니다. 파이썬 3.10에서 제거됩니다.

더 일반적으로, 파이썬 개발 모드에서 테스트를 실행하면 다음 파이썬 버전과 호환되도록 코드를 준비하는 데 도움이 됩니다.

참고: 이 버전의 파이썬에서 기존의 많은 폐지가 제거되기도 했습니다. 제거 섹션을 참조하십시오.

새로운 기능

딕셔너리 병합과 업데이트 연산자

내장 dict 클래스에 병합(|)과 업데이트(|=) 연산자가 추가되었습니다. 이들은 딕셔너리 병합의 기존 dict.update와 {**d1, **d2} 메서드를 보완합니다.

예:

>>> x = {"key1": "value1 from x", "key2": "value2 from x"}
>>> y = {"key2": "value2 from y", "key3": "value3 from y"}
>>> x | y
{'key1': 'value1 from x', 'key2': 'value2 from y', 'key3': 'value3 from y'}
>>> y | x
{'key2': 'value2 from x', 'key3': 'value3 from y', 'key1': 'value1 from x'}

자세한 설명은 PEP 584 [https://peps.python.org/pep-0584/]를 참조하십시오. (Contributed by Brandt Bucher in bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144].)

접두사와 접미사를 제거하는 새로운 문자열 메서드

문자열에서 불필요한 접두사나 접미사를 쉽게 제거하기 위해 str.removeprefix(prefix)와 str.removesuffix(suffix)가 추가되었습니다. 해당 bytes, bytearray 및 collections.UserString 메서드도 추가되었습니다. 자세한 설명은 PEP 616 [https://peps.python.org/pep-0616/]을 참조하십시오. (Contributed by Dennis Sweeney in bpo-39939 [https://bugs.python.org/issue?@action=redirect&bpo=39939].)

표준 컬렉션의 형 힌트 제네릭

형 어노테이션에서 이제 typing에서 해당 대문자 형(예를 들어 List나 Dict)을 임포트 하는 대신 list와 dict와 같은 내장 컬렉션 형을 제네릭 형으로 사용할 수 있습니다. 표준 라이브러리의 일부 다른 형도 이제 제네릭입니다, 예를 들어 queue.Queue.

예:

def greet_all(names: list[str]) -> None:
    for name in names:
        print("Hello", name)

자세한 내용은 PEP 585 [https://peps.python.org/pep-0585/]를 참조하십시오. (Contributed by Guido van Rossum, Ethan Smith, and Batuhan Taşkaya in bpo-39481 [https://bugs.python.org/issue?@action=redirect&bpo=39481].)

새로운 구문 분석기

파이썬 3.9는 LL(1) [https://en.wikipedia.org/wiki/LL_parser] 대신 PEG [https://en.wikipedia.org/wiki/Parsing_expression_grammar]를 기반으로 하는 새로운 구문 분석기를 사용합니다. 새로운 구문 분석기의 성능은 기존 구문 분석기의 성능과 거의 비슷하지만, PEG 형식은 새로운 언어 기능을 설계할 때 LL(1)보다 더 유연합니다. 파이썬 3.10 이상에서 이 유연성을 사용하기 시작할 것입니다.

ast 모듈은 새 구문 분석기를 사용하며 이전 구문 분석기와 같은 AST를 생성합니다.

In Python 3.10, the old parser will be deleted and so will all functionality that depends on it (primarily the parser module, which has long been deprecated). In Python 3.9 only, you can switch back to the LL(1) parser using a command line switch (-X oldparser) or an environment variable (PYTHONOLDPARSER=1).

자세한 내용은 PEP 617 [https://peps.python.org/pep-0617/]을 참조하십시오. (Contributed by Guido van Rossum, Pablo Galindo and Lysandros Nikolaou in bpo-40334 [https://bugs.python.org/issue?@action=redirect&bpo=40334].)

기타 언어 변경

__import__()는 이제 ValueError 대신 ImportError를 발생시킵니다. 이는 상대적 임포트가 최상위 수준 패키지를 넘어갈 때 발생했습니다. (Contributed by Ngalim Siregar in bpo-37444 [https://bugs.python.org/issue?@action=redirect&bpo=37444].)

파이썬은 이제 명령 줄에 지정된 스크립트 파일 이름의 절대 경로를 얻습니다 (예: python3 script.py): __main__ 모듈의 __file__ 어트리뷰트는 상대 경로 대신 절대 경로가 됩니다. 이 경로는 현재 디렉터리가 os.chdir()에 의해 변경된 후에도 계속 유효합니다. 부작용으로, 이 경우 트레이스백은 __main__ 모듈 프레임에 대해 절대 경로를 표시합니다. (Contributed by Victor Stinner in bpo-20443 [https://bugs.python.org/issue?@action=redirect&bpo=20443].)

In the Python Development Mode and in debug build, the encoding and errors arguments are now checked for string encoding and decoding operations. Examples: open(), str.encode() and bytes.decode().

기본적으로, 최상의 성능을 위해, errors 인자는 첫 번째 인코딩/디코딩 에러에서만 확인되며 빈 문자열에 대해서는 encoding 인자가 무시되는 경우가 있습니다. (Contributed by Victor Stinner in bpo-37388 [https://bugs.python.org/issue?@action=redirect&bpo=37388].)

"".replace("", s, n)는 이제 0이 아닌 모든 n에 대해 빈 문자열 대신 s를 반환합니다. 이제 "".replace("", s)와 일관성 있습니다. bytes와 bytearray 객체에 대해 유사한 변경 사항이 있습니다. (Contributed by Serhiy Storchaka in bpo-28029 [https://bugs.python.org/issue?@action=redirect&bpo=28029].)

이제 모든 유효한 표현식을 데코레이터로 사용할 수 있습니다. 이전에는, 문법이 훨씬 제한적이었습니다. 자세한 내용은 PEP 614 [https://peps.python.org/pep-0614/]를 참조하십시오. (Contributed by Brandt Bucher in bpo-39702 [https://bugs.python.org/issue?@action=redirect&bpo=39702].)

typing 모듈에 대한 도움말이 개선되었습니다. 모든 특수 형식과 특수 제네릭 에일리어스(Union과 List 같은)에 대한 독스트링이 이제 표시됩니다. List[int]와 같은 제네릭 에일리어스로 help()를 사용하면 해당 구상형(이 경우 list)에 대한 도움말이 표시됩니다. (Contributed by Serhiy Storchaka in bpo-40257 [https://bugs.python.org/issue?@action=redirect&bpo=40257].)

aclose() / asend() / athrow()의 병렬 실행은 이제 금지되며, 이제 ag_running은 비동기 제너레이터의 실제 실행 상태를 반영합니다. (Contributed by Yury Selivanov in bpo-30773 [https://bugs.python.org/issue?@action=redirect&bpo=30773].)

__iter__ 메서드 호출 시 예기치 않은 에러가 더는 in 연산자와 operator 모듈의 contains(), indexOf() 및 countOf() 함수에서 TypeError에 의해 마스킹 되지 않습니다. (Contributed by Serhiy Storchaka in bpo-40824 [https://bugs.python.org/issue?@action=redirect&bpo=40824].)

Unparenthesized lambda expressions can no longer be the expression part in an if clause in comprehensions and generator expressions. See bpo-41848 [https://bugs.python.org/issue?@action=redirect&bpo=41848] and bpo-43755 [https://bugs.python.org/issue?@action=redirect&bpo=43755] for details.

새 모듈

zoneinfo

zoneinfo 모듈은 IANA 시간대 데이터베이스 지원을 표준 라이브러리에 도입합니다. 시스템의 시간대 데이터로 뒷받침되는 구상 datetime.tzinfo 구현인 zoneinfo.ZoneInfo를 추가합니다.

예:

>>> from zoneinfo import ZoneInfo
>>> from datetime import datetime, timedelta

>>> # Daylight saving time
>>> dt = datetime(2020, 10, 31, 12, tzinfo=ZoneInfo("America/Los_Angeles"))
>>> print(dt)
2020-10-31 12:00:00-07:00
>>> dt.tzname()
'PDT'

>>> # Standard time
>>> dt += timedelta(days=7)
>>> print(dt)
2020-11-07 12:00:00-08:00
>>> print(dt.tzname())
PST

As a fall-back source of data for platforms that don’t ship the IANA database, the tzdata [https://pypi.org/project/tzdata/] module was released as a first-party package – distributed via PyPI and maintained by the CPython core team.

더 보기

PEP 615 [https://peps.python.org/pep-0615/] – 표준 라이브러리의 IANA 시간대 데이터베이스에 대한 지원

Paul Ganssle이 작성하고 구현한 PEP

graphlib

graphlib.TopologicalSorter 클래스를 포함하는 graphlib를 추가하여 그래프의 위상 정렬을 수행하는 기능을 제공합니다. (Contributed by Pablo Galindo, Tim Peters and Larry Hastings in bpo-17005 [https://bugs.python.org/issue?@action=redirect&bpo=17005].)

개선된 모듈

ast

indent 옵션을 dump()에 추가하여 여러 줄 들여쓰기 된 출력을 생성할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-37995 [https://bugs.python.org/issue?@action=redirect&bpo=37995].)

ast.AST 객체를 역 구문 분석하고, 구문 분석할 때 동등한 ast.AST 객체를 생성하는 코드가 담긴 문자열을 생성하는 데 사용할 수 있는 ast.unparse()를 ast 모듈의 함수로 추가했습니다. (Contributed by Pablo Galindo and Batuhan Taskaya in bpo-38870 [https://bugs.python.org/issue?@action=redirect&bpo=38870].)

AST 노드를 생성하는 데 사용된 ASDL 서명이 포함된 독스트링을 AST 노드에 추가했습니다. (Contributed by Batuhan Taskaya in bpo-39638 [https://bugs.python.org/issue?@action=redirect&bpo=39638].)

asyncio

심각한 보안 문제로 인해, asyncio.loop.create_datagram_endpoint()의 reuse_address 매개 변수는 더는 지원되지 않습니다. 이것은 UDP에서 소켓 옵션 SO_REUSEADDR의 동작 때문입니다. 자세한 내용은 loop.create_datagram_endpoint() 설명서를 참조하십시오. (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228].)

ThreadPoolExecutor가 닫기를 끝내기를 기다리는 기본 실행기의 종료(shutdown)를 예약하는 새 코루틴 shutdown_default_executor()가 추가되었습니다. 또한, asyncio.run()은 새로운 코루틴을 사용하도록 갱신되었습니다. (Contributed by Kyle Stanley in bpo-34037 [https://bugs.python.org/issue?@action=redirect&bpo=34037].)

Added asyncio.PidfdChildWatcher, a Linux-specific child watcher implementation that polls process file descriptors. (bpo-38692 [https://bugs.python.org/issue?@action=redirect&bpo=38692])

새로운 코루틴 asyncio.to_thread()를 추가했습니다. 주로 이벤트 루프 블록을 피하고자 별도의 스레드에서 IO 병목 함수를 실행하는 데 사용되며, 기본적으로 키워드 인자를 직접 취할 수 있는 run_in_executor()의 고수준 버전으로 작동합니다. (Contributed by Kyle Stanley and Yury Selivanov in bpo-32309 [https://bugs.python.org/issue?@action=redirect&bpo=32309].)

시간 초과로 인해 태스크를 취소할 때, asyncio.wait_for()는 이제 양의 timeout과 마찬가지로 timeout이 <= 0 인 경우에도 취소가 완료될 때까지 기다립니다. (Contributed by Elvis Pranskevichus in bpo-32751 [https://bugs.python.org/issue?@action=redirect&bpo=32751].)

asyncio now raises TypeError when calling incompatible methods with an ssl.SSLSocket socket. (Contributed by Ido Michael in bpo-37404 [https://bugs.python.org/issue?@action=redirect&bpo=37404].)

compileall

복제된 .pyc 파일에 대해 하드 링크를 사용하는 새로운 가능성이 추가되었습니다: hardlink_dupes 매개 변수와 –hardlink-dupes 명령 줄 옵션. (Contributed by Lumír ‘Frenzy’ Balhar in bpo-40495 [https://bugs.python.org/issue?@action=redirect&bpo=40495].)

결과 .pyc 파일에서 경로 조작을 위한 새로운 옵션을 추가했습니다: stripdir, prependdir, limit_sl_dest 매개 변수와 -s, -p, -e 명령 줄 옵션. 최적화 수준에 대한 옵션을 여러 번 지정할 수 있는 가능성이 추가되었습니다. (Contributed by Lumír ‘Frenzy’ Balhar in bpo-38112 [https://bugs.python.org/issue?@action=redirect&bpo=38112].)

concurrent.futures

실행기를 종료하기 전에 완료되기를 기다리는 대신, 실행을 시작하지 않은 모든 계류 중인 퓨처를 취소하는 새 cancel_futures 매개 변수를 concurrent.futures.Executor.shutdown()에 추가했습니다. (Contributed by Kyle Stanley in bpo-39349 [https://bugs.python.org/issue?@action=redirect&bpo=39349].)

ThreadPoolExecutor와 ProcessPoolExecutor 에서 데몬 스레드를 제거했습니다. 이를 통해 종료 절차에서 서브 인터프리터와의 호환성과 예측성이 향상됩니다. (Contributed by Kyle Stanley in bpo-39812 [https://bugs.python.org/issue?@action=redirect&bpo=39812].)

재사용 가능한 유휴 작업자가 없을 때만, ProcessPoolExecutor 의 작업자가 요청 시 스폰 됩니다. 이는 시작 오버헤드를 최적화하고 유휴 작업자에게 손실되는 CPU 시간을 줄입니다. (Contributed by Kyle Stanley in bpo-39207 [https://bugs.python.org/issue?@action=redirect&bpo=39207].)

curses

curses.get_escdelay(), curses.set_escdelay(), curses.get_tabsize() 및 curses.set_tabsize() 함수를 추가했습니다. (Contributed by Anthony Sottile in bpo-38312 [https://bugs.python.org/issue?@action=redirect&bpo=38312].)

datetime

The isocalendar() of datetime.date and isocalendar() of datetime.datetime methods now returns a namedtuple() instead of a tuple. (Contributed by Donghee Na in bpo-24416 [https://bugs.python.org/issue?@action=redirect&bpo=24416].)

distutils

upload 명령은 이제 SHA2-256 및 Blake2b-256 해시 다이제스트를 만듭니다. MD5 다이제스트를 차단하는 플랫폼에서는 MD5를 건너뜁니다. (Contributed by Christian Heimes in bpo-40698 [https://bugs.python.org/issue?@action=redirect&bpo=40698].)

fcntl

Added constants F_OFD_GETLK, F_OFD_SETLK and F_OFD_SETLKW. (Contributed by Donghee Na in bpo-38602 [https://bugs.python.org/issue?@action=redirect&bpo=38602].)

ftplib

FTP and FTP_TLS now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. (Contributed by Donghee Na in bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259].)

gc

가비지 수거기가 일부 객체를 되살리는 컬렉션을 만들 때 (파이널라이저가 실행된 후 격리된 순환 외부에서 도달할 수 있습니다), 여전히 도달할 수 없는 모든 객체의 컬렉션을 차단하지 않습니다. (Contributed by Pablo Galindo and Tim Peters in bpo-38379 [https://bugs.python.org/issue?@action=redirect&bpo=38379].)

가비지 수거기에서 객체가 파이널라이즈 되었는지 확인하는 새 함수 gc.is_finalized()를 추가했습니다. (Contributed by Pablo Galindo in bpo-39322 [https://bugs.python.org/issue?@action=redirect&bpo=39322].)

hashlib

hashlib 모듈은 이제 사용할 수 있으면 OpenSSL의 SHA3 해시와 SHAKE XOF를 사용할 수 있습니다. (Contributed by Christian Heimes in bpo-37630 [https://bugs.python.org/issue?@action=redirect&bpo=37630].)

내장 해시 모듈은 이제 ./configure --without-builtin-hashlib-hashes로 비활성화하거나 ./configure --with-builtin-hashlib-hashes=sha3,blake2로 선택적으로 활성화하여 OpenSSL 기반 구현의 사용을 강제할 수 있습니다. (Contributed by Christian Heimes in bpo-40479 [https://bugs.python.org/issue?@action=redirect&bpo=40479])

http

HTTP status codes 103 EARLY_HINTS, 418 IM_A_TEAPOT and 425 TOO_EARLY are added to http.HTTPStatus. (Contributed by Donghee Na in bpo-39509 [https://bugs.python.org/issue?@action=redirect&bpo=39509] and Ross Rhodes in bpo-39507 [https://bugs.python.org/issue?@action=redirect&bpo=39507].)

IDLE과 idlelib

커서 깜박임을 토글하는 옵션이 추가되었습니다. (Contributed by Zackery Spytz in bpo-4603 [https://bugs.python.org/issue?@action=redirect&bpo=4603].)

이스케이프 키는 이제 IDLE 완료 창을 닫습니다. (Contributed by Johnny Najera in bpo-38944 [https://bugs.python.org/issue?@action=redirect&bpo=38944].)

모듈 이름 완성 리스트에 키워드를 추가했습니다. (Contributed by Terry J. Reedy in bpo-37765 [https://bugs.python.org/issue?@action=redirect&bpo=37765].)

New in 3.9 maintenance releases

Make IDLE invoke sys.excepthook() (when started without ‘-n’). User hooks were previously ignored. (Contributed by Ken Hilton in bpo-43008 [https://bugs.python.org/issue?@action=redirect&bpo=43008].)

위의 변경 사항은 3.8 유지 보수 릴리스로 역 이식되었습니다.

Rearrange the settings dialog. Split the General tab into Windows and Shell/Ed tabs. Move help sources, which extend the Help menu, to the Extensions tab. Make space for new options and shorten the dialog. The latter makes the dialog better fit small screens. (Contributed by Terry Jan Reedy in bpo-40468 [https://bugs.python.org/issue?@action=redirect&bpo=40468].) Move the indent space setting from the Font tab to the new Windows tab. (Contributed by Mark Roseman and Terry Jan Reedy in bpo-33962 [https://bugs.python.org/issue?@action=redirect&bpo=33962].)

Apply syntax highlighting to .pyi files. (Contributed by Alex Waygood and Terry Jan Reedy in bpo-45447 [https://bugs.python.org/issue?@action=redirect&bpo=45447].)

imaplib

IMAP4 and IMAP4_SSL now have an optional timeout parameter for their constructors. Also, the open() method now has an optional timeout parameter with this change. The overridden methods of IMAP4_SSL and IMAP4_stream were applied to this change. (Contributed by Donghee Na in bpo-38615 [https://bugs.python.org/issue?@action=redirect&bpo=38615].)

imaplib.IMAP4.unselect() is added. imaplib.IMAP4.unselect() frees server’s resources associated with the selected mailbox and returns the server to the authenticated state. This command performs the same actions as imaplib.IMAP4.close(), except that no messages are permanently removed from the currently selected mailbox. (Contributed by Donghee Na in bpo-40375 [https://bugs.python.org/issue?@action=redirect&bpo=40375].)

importlib

import 문과의 일관성을 개선하기 위해, importlib.util.resolve_name()은 이제 잘못된 상대 임포트 시도에 대해 ValueError 대신 ImportError를 발생시킵니다. (Contributed by Ngalim Siregar in bpo-37444 [https://bugs.python.org/issue?@action=redirect&bpo=37444].)

불변 모듈 객체를 게시하는 임포트 로더는 이제 개별 모듈 외에도 불변 패키지를 게시할 수 있습니다. (Contributed by Dino Viehland in bpo-39336 [https://bugs.python.org/issue?@action=redirect&bpo=39336].)

importlib_resources 버전 1.5의 역 이식과 일치하는 패키지 데이터의 하위 디렉터리를 지원하는 importlib.resources.files() 함수가 추가되었습니다. (Contributed by Jason R. Coombs in bpo-39791 [https://bugs.python.org/issue?@action=redirect&bpo=39791].)

importlib_metadata 버전 1.6.1로부터 importlib.metadata를 새로 고쳤습니다.

inspect

inspect.BoundArguments.arguments가 OrderedDict에서 일반 dict로 변경되었습니다. (Contributed by Inada Naoki in bpo-36350 [https://bugs.python.org/issue?@action=redirect&bpo=36350] and bpo-39775 [https://bugs.python.org/issue?@action=redirect&bpo=39775].)

ipaddress

ipaddress는 이제 IPv6 스코프 된 주소(접미사 %<scope_id> 가 있는 IPv6 주소)를 지원합니다.

스코프 된 IPv6 주소는 ipaddress.IPv6Address를 사용하여 구문 분석할 수 있습니다. 존재하면, scope_id 어트리뷰트를 통해 스코프 존 ID를 사용할 수 있습니다. (Contributed by Oleksandr Pavliuk in bpo-34788 [https://bugs.python.org/issue?@action=redirect&bpo=34788].)

Starting with Python 3.9.5 the ipaddress module no longer accepts any leading zeros in IPv4 address strings. (Contributed by Christian Heimes in bpo-36384 [https://bugs.python.org/issue?@action=redirect&bpo=36384]).

math

여러 인자를 처리하도록 math.gcd() 함수를 확장했습니다. 이전에는 두 개의 인자만 지원했습니다. (Contributed by Serhiy Storchaka in bpo-39648 [https://bugs.python.org/issue?@action=redirect&bpo=39648].)

math.lcm()을 추가했습니다: 지정된 인자의 최소 공배수를 반환합니다. (Contributed by Mark Dickinson, Ananthakrishnan and Serhiy Storchaka in bpo-39479 [https://bugs.python.org/issue?@action=redirect&bpo=39479] and bpo-39648 [https://bugs.python.org/issue?@action=redirect&bpo=39648].)

math.nextafter()를 추가했습니다: y를 향해 x 뒤의 다음 부동 소수점 값을 반환합니다. (Contributed by Victor Stinner in bpo-39288 [https://bugs.python.org/issue?@action=redirect&bpo=39288].)

math.ulp()를 추가했습니다: 부동 소수점의 최하위 비트 값을 반환합니다. (Contributed by Victor Stinner in bpo-39310 [https://bugs.python.org/issue?@action=redirect&bpo=39310].)

multiprocessing

multiprocessing.SimpleQueue 클래스에는 큐를 명시적으로 닫는 새로운 close() 메서드가 있습니다. (Contributed by Victor Stinner in bpo-30966 [https://bugs.python.org/issue?@action=redirect&bpo=30966].)

nntplib

NNTP and NNTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. (Contributed by Donghee Na in bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259].)

os

Added CLD_KILLED and CLD_STOPPED for si_code. (Contributed by Donghee Na in bpo-38493 [https://bugs.python.org/issue?@action=redirect&bpo=38493].)

Exposed the Linux-specific os.pidfd_open() (bpo-38692 [https://bugs.python.org/issue?@action=redirect&bpo=38692]) and os.P_PIDFD (bpo-38713 [https://bugs.python.org/issue?@action=redirect&bpo=38713]) for process management with file descriptors.

os.unsetenv() 함수는 이제 윈도우에서도 사용할 수 있습니다. (Contributed by Victor Stinner in bpo-39413 [https://bugs.python.org/issue?@action=redirect&bpo=39413].)

os.putenv()와 os.unsetenv() 함수를 이제 항상 사용할 수 있습니다. (Contributed by Victor Stinner in bpo-39395 [https://bugs.python.org/issue?@action=redirect&bpo=39395].)

os.waitstatus_to_exitcode() 함수를 추가했습니다: 대기 상태를 종료 코드로 변환합니다. (Contributed by Victor Stinner in bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094].)

pathlib

Added pathlib.Path.readlink() which acts similarly to os.readlink(). (Contributed by Girts Folkmanis in bpo-30618 [https://bugs.python.org/issue?@action=redirect&bpo=30618])

pdb

이제 윈도우에서 Pdb는 ~/.pdbrc를 지원합니다. (Contributed by Tim Hopper and Dan Lidral-Porter in bpo-20523 [https://bugs.python.org/issue?@action=redirect&bpo=20523].)

poplib

POP3 and POP3_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. (Contributed by Donghee Na in bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259].)

pprint

pprint는 이제 types.SimpleNamespace를 예쁘게 인쇄 할 수 있습니다. (Contributed by Carl Bordum Hansen in bpo-37376 [https://bugs.python.org/issue?@action=redirect&bpo=37376].)

pydoc

The documentation string is now shown not only for class, function, method etc, but for any object that has its own __doc__ attribute. (Contributed by Serhiy Storchaka in bpo-40257 [https://bugs.python.org/issue?@action=redirect&bpo=40257].)

random

새로운 random.Random.randbytes 메서드를 추가했습니다: 무작위 바이트열을 생성합니다. (Contributed by Victor Stinner in bpo-40286 [https://bugs.python.org/issue?@action=redirect&bpo=40286].)

signal

pid 대신 파일 기술자를 사용하여 프로세스에 시그널을 보내는 리눅스 특정 signal.pidfd_send_signal()을 노출했습니다. (bpo-38712 [https://bugs.python.org/issue?@action=redirect&bpo=38712])

smtplib

SMTP and SMTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. (Contributed by Donghee Na in bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259].)

LMTP constructor now has an optional timeout parameter. (Contributed by Donghee Na in bpo-39329 [https://bugs.python.org/issue?@action=redirect&bpo=39329].)

socket

The socket module now exports the CAN_RAW_JOIN_FILTERS constant on Linux 4.1 and greater. (Contributed by Stefan Tatschner and Zackery Spytz in bpo-25780 [https://bugs.python.org/issue?@action=redirect&bpo=25780].)

The socket module now supports the CAN_J1939 protocol on platforms that support it. (Contributed by Karl Ding in bpo-40291 [https://bugs.python.org/issue?@action=redirect&bpo=40291].)

The socket module now has the socket.send_fds() and socket.recv_fds() functions. (Contributed by Joannah Nanjekye, Shinya Okano and Victor Stinner in bpo-28724 [https://bugs.python.org/issue?@action=redirect&bpo=28724].)

time

On AIX, thread_time() is now implemented with thread_cputime() which has nanosecond resolution, rather than clock_gettime(CLOCK_THREAD_CPUTIME_ID) which has a resolution of 10 milliseconds. (Contributed by Batuhan Taskaya in bpo-40192 [https://bugs.python.org/issue?@action=redirect&bpo=40192])

sys

Added a new sys.platlibdir attribute: name of the platform-specific library directory. It is used to build the path of standard library and the paths of installed extension modules. It is equal to "lib" on most platforms. On Fedora and SuSE, it is equal to "lib64" on 64-bit platforms. (Contributed by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner in bpo-1294959 [https://bugs.python.org/issue?@action=redirect&bpo=1294959].)

Previously, sys.stderr was block-buffered when non-interactive. Now stderr defaults to always being line-buffered. (Contributed by Jendrik Seipp in bpo-13601 [https://bugs.python.org/issue?@action=redirect&bpo=13601].)

tracemalloc

특정 코드 조각의 최대 사용량을 측정하기 위해 추적한 메모리 블록의 최대 크기를 현재 크기로 설정하는 tracemalloc.reset_peak()가 추가되었습니다. (Contributed by Huon Wilson in bpo-40630 [https://bugs.python.org/issue?@action=redirect&bpo=40630].)

typing

PEP 593 [https://peps.python.org/pep-0593/]은 문맥 별 메타 데이터로 기존 형을 데코레이트 하는 typing.Annotated 형과 실행 시간에 메타 데이터에 액세스하기 위해 typing.get_type_hints()에 새로운 include_extras 매개 변수를 도입했습니다. (Contributed by Till Varoquaux and Konstantin Kashin.)

unicodedata

유니코드 데이터베이스가 버전 13.0.0으로 갱신되었습니다. (bpo-39926 [https://bugs.python.org/issue?@action=redirect&bpo=39926]).

venv

venv가 제공하는 활성화 스크립트는 이제 모두 항상 __VENV_PROMPT__로 지정된 값을 사용하여 프롬프트 사용자 정의를 일관되게 지정합니다. 이전에는 일부 스크립트는 __VENV_PROMPT__를 무조건 사용했으며, 다른 스크립트는 설정되었을 때만 (이것이 기본입니다) __VENV_PROMPT__를 사용했으며 어떤 것은 대신 __VENV_NAME__을 사용했습니다. (Contributed by Brett Cannon in bpo-37663 [https://bugs.python.org/issue?@action=redirect&bpo=37663].)

xml

xml.etree.ElementTree를 XML 파일로 직렬화할 때 어트리뷰트 내의 공백 문자가 이제 유지됩니다. EOLN은 더는 “n”으로 정규화되지 않습니다. 이것은 XML 명세의 2.11 섹션을 해석하는 방법에 대한 논의 결과입니다. (Contributed by Mefistotelis in bpo-39011 [https://bugs.python.org/issue?@action=redirect&bpo=39011].)

최적화

컴프리헨션에서 임시 변수를 대입하는 관용구를 최적화했습니다. 이제 컴프리헨션에서 for y in [expr]는 단순 대입 y = expr만큼 빠릅니다. 예를 들면:

sums = [s for s in [0] for x in data for s in [s + x]]

:= 연산자와 달리 이 관용구는 변수를 외부 스코프로 누출하지 않습니다.

(Contributed by Serhiy Storchaka in bpo-32856 [https://bugs.python.org/issue?@action=redirect&bpo=32856].)

다중 스레드 응용 프로그램에서 시그널 처리를 최적화했습니다. 메인 스레드와 다른 스레드가 신호를 받으면, 처리할 수 없는 계류 중인 시그널을 확인하기 위해 바이트 코드 평가 루프가 더는 각 바이트 코드 명령에서 중단되지 않습니다. 메인 인터프리터의 메인 스레드만 시그널을 처리할 수 있습니다.

이전에는, 메인 스레드가 시그널을 처리할 때까지 각 명령에서 바이트 코드 평가 루프가 중단되었습니다. (Contributed by Victor Stinner in bpo-40010 [https://bugs.python.org/issue?@action=redirect&bpo=40010].)

closefrom()을 사용하여 FreeBSD에서 subprocess 모듈을 최적화했습니다. (Contributed by Ed Maste, Conrad Meyer, Kyle Evans, Kubilay Kocak and Victor Stinner in bpo-38061 [https://bugs.python.org/issue?@action=redirect&bpo=38061].)

PyLong_FromDouble() is now up to 1.87x faster for values that fit into long. (Contributed by Sergey Fedoseev in bpo-37986 [https://bugs.python.org/issue?@action=redirect&bpo=37986].)

A number of Python builtins (range, tuple, set, frozenset, list, dict) are now sped up by using PEP 590 [https://peps.python.org/pep-0590/] vectorcall protocol. (Contributed by Donghee Na, Mark Shannon, Jeroen Demeyer and Petr Viktorin in bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207].)

다른 집합이 기본 집합보다 훨씬 큰 경우에 최적화된 difference_update(). (Suggested by Evgeny Kapun with code contributed by Michele Orrù in bpo-8425 [https://bugs.python.org/issue?@action=redirect&bpo=8425].)

파이썬의 작은 객체 할당자(obmalloc.c)는 이제 하나의 빈 아레나를 OS로 반환하지 않고 즉시 재사용 할 수 있도록 허용합니다. 이렇게 하면 각 이터레이션마다 아레나가 새로 만들어지고 파괴될 수 있도록 하는 간단한 루프에서의 스레싱(thrashing)이 방지됩니다. (Contributed by Tim Peters in bpo-37257 [https://bugs.python.org/issue?@action=redirect&bpo=37257].)

floor division of float operation now has a better performance. Also the message of ZeroDivisionError for this operation is updated. (Contributed by Donghee Na in bpo-39434 [https://bugs.python.org/issue?@action=redirect&bpo=39434].)

UTF-8과 ascii 코덱으로 짧은 ASCII 문자열을 디코딩하는 것이 이제 약 15% 더 빨라졌습니다. (Contributed by Inada Naoki in bpo-37348 [https://bugs.python.org/issue?@action=redirect&bpo=37348].)

다음은 파이썬 3.4에서 파이썬 3.9까지의 성능 향상에 대한 요약입니다:

Python version                       3.4     3.5     3.6     3.7     3.8    3.9
--------------                       ---     ---     ---     ---     ---    ---

Variable and attribute read access:
    read_local                       7.1     7.1     5.4     5.1     3.9    3.9
    read_nonlocal                    7.1     8.1     5.8     5.4     4.4    4.5
    read_global                     15.5    19.0    14.3    13.6     7.6    7.8
    read_builtin                    21.1    21.6    18.5    19.0     7.5    7.8
    read_classvar_from_class        25.6    26.5    20.7    19.5    18.4   17.9
    read_classvar_from_instance     22.8    23.5    18.8    17.1    16.4   16.9
    read_instancevar                32.4    33.1    28.0    26.3    25.4   25.3
    read_instancevar_slots          27.8    31.3    20.8    20.8    20.2   20.5
    read_namedtuple                 73.8    57.5    45.0    46.8    18.4   18.7
    read_boundmethod                37.6    37.9    29.6    26.9    27.7   41.1

Variable and attribute write access:
    write_local                      8.7     9.3     5.5     5.3     4.3    4.3
    write_nonlocal                  10.5    11.1     5.6     5.5     4.7    4.8
    write_global                    19.7    21.2    18.0    18.0    15.8   16.7
    write_classvar                  92.9    96.0   104.6   102.1    39.2   39.8
    write_instancevar               44.6    45.8    40.0    38.9    35.5   37.4
    write_instancevar_slots         35.6    36.1    27.3    26.6    25.7   25.8

Data structure read access:
    read_list                       24.2    24.5    20.8    20.8    19.0   19.5
    read_deque                      24.7    25.5    20.2    20.6    19.8   20.2
    read_dict                       24.3    25.7    22.3    23.0    21.0   22.4
    read_strdict                    22.6    24.3    19.5    21.2    18.9   21.5

Data structure write access:
    write_list                      27.1    28.5    22.5    21.6    20.0   20.0
    write_deque                     28.7    30.1    22.7    21.8    23.5   21.7
    write_dict                      31.4    33.3    29.3    29.2    24.7   25.4
    write_strdict                   28.4    29.9    27.5    25.2    23.1   24.5

Stack (or queue) operations:
    list_append_pop                 93.4   112.7    75.4    74.2    50.8   50.6
    deque_append_pop                43.5    57.0    49.4    49.2    42.5   44.2
    deque_append_popleft            43.7    57.3    49.7    49.7    42.8   46.4

Timing loop:
    loop_overhead                    0.5     0.6     0.4     0.3     0.3    0.3

These results were generated from the variable access benchmark script at: Tools/scripts/var_access_benchmark.py. The benchmark script displays timings in nanoseconds. The benchmarks were measured on an Intel® Core™ i7-4960HQ processor [https://ark.intel.com/content/www/us/en/ark/products/76088/intel-core-i7-4960hq-processor-6m-cache-up-to-3-80-ghz.html] running the macOS 64-bit builds found at python.org [https://www.python.org/downloads/macos/].

폐지

distutils bdist_msi 명령은 이제 폐지되었습니다, 대신 bdist_wheel(휠 패키지)을 사용하십시오. (Contributed by Hugo van Kemenade in bpo-39586 [https://bugs.python.org/issue?@action=redirect&bpo=39586].)

현재 math.factorial()은 음이 아닌 정숫값을 갖는 float 인스턴스를 허용합니다 (가령 5.0). 정숫값이 아니거나 음수인 float에 대해서는 ValueError를 발생시킵니다. 이제 폐지되었습니다. 향후 파이썬 버전에서는 모든 float에 대해 TypeError를 발생시킬 것입니다. (Contributed by Serhiy Storchaka in bpo-37315 [https://bugs.python.org/issue?@action=redirect&bpo=37315].)

The parser and symbol modules are deprecated and will be removed in future versions of Python. For the majority of use cases, users can leverage the Abstract Syntax Tree (AST) generation and compilation stage, using the ast module.

The Public C API functions PyParser_SimpleParseStringFlags(), PyParser_SimpleParseStringFlagsFilename(), PyParser_SimpleParseFileFlags() and PyNode_Compile() are deprecated and will be removed in Python 3.10 together with the old parser.

불리언 문맥에서 NotImplemented를 사용하는 것은 거의 확실히 잘못된 풍부한 비교 구현의 결과이므로 폐지되었습니다. 향후 버전의 파이썬에서 TypeError가 될 것입니다. (Contributed by Josh Rosenberg in bpo-35712 [https://bugs.python.org/issue?@action=redirect&bpo=35712].)

random 모듈은 현재 모든 해시 가능한 형을 시드 값으로 허용합니다. 불행히도, 이러한 형 중 일부는 결정론적 해시값을 보장하지 않습니다. 파이썬 3.9 이후, 이 모듈은 시드를 None, int, float, str, bytes 및 bytearray로 제한합니다.

mode 인자를 지정하지 않고 쓰기 위해 GzipFile 파일을 여는 것은 폐지되었습니다. 향후 파이썬 버전에서는 이때 기본적으로 항상 읽기 위해 열립니다. 쓰기 위해 열면서 경고가 나오지 않도록 하기 위해서는 mode 인자를 지정하십시오. (Contributed by Serhiy Storchaka in bpo-28286 [https://bugs.python.org/issue?@action=redirect&bpo=28286].)

Deprecated the split() method of _tkinter.TkappType in favour of the splitlist() method which has more consistent and predictable behavior. (Contributed by Serhiy Storchaka in bpo-38371 [https://bugs.python.org/issue?@action=redirect&bpo=38371].)

코루틴 객체를 asyncio.wait()에 명시적으로 전달하는 것은 폐지되었고 버전 3.11에서 제거됩니다. (Contributed by Yury Selivanov and Kyle Stanley in bpo-34790 [https://bugs.python.org/issue?@action=redirect&bpo=34790].)

binhex4 and hexbin4 standards are now deprecated. The binhex module and the following binascii functions are now deprecated:

b2a_hqx(), a2b_hqx()

rlecode_hqx(), rledecode_hqx()

(Contributed by Victor Stinner in bpo-39353 [https://bugs.python.org/issue?@action=redirect&bpo=39353].)

ast 클래스 slice, Index 및 ExtSlice는 폐지된 것으로 간주하고 향후 파이썬 버전에서 제거될 예정입니다. Index(value) 대신 value 자체를 사용해야 합니다. ExtSlice(slices) 대신 Tuple(slices, Load())를 사용해야 합니다. (Contributed by Serhiy Storchaka in bpo-34822 [https://bugs.python.org/issue?@action=redirect&bpo=34822].)

ast 클래스 Suite, Param, AugLoad 및 AugStore는 폐지된 것으로 간주하고 향후 파이썬 버전에서 제거될 예정입니다. 이것들은 구문 분석기에 의해 생성되지 않았으며 파이썬 3의 코드 생성기에 의해 받아들여지지 않았습니다. (Contributed by Batuhan Taskaya in bpo-39639 [https://bugs.python.org/issue?@action=redirect&bpo=39639] and bpo-39969 [https://bugs.python.org/issue?@action=redirect&bpo=39969] and Serhiy Storchaka in bpo-39988 [https://bugs.python.org/issue?@action=redirect&bpo=39988].)

The PyEval_InitThreads() and PyEval_ThreadsInitialized() functions are now deprecated and will be removed in Python 3.11. Calling PyEval_InitThreads() now does nothing. The GIL is initialized by Py_Initialize() since Python 3.7. (Contributed by Victor Stinner in bpo-39877 [https://bugs.python.org/issue?@action=redirect&bpo=39877].)

shlex.split() 함수에 첫 번째 인자로 None을 전달하는 것은 폐지되었습니다. (Contributed by Zackery Spytz in bpo-33262 [https://bugs.python.org/issue?@action=redirect&bpo=33262].)

smtpd.MailmanProxy() is now deprecated as it is unusable without an external module, mailman. (Contributed by Samuel Colvin in bpo-35800 [https://bugs.python.org/issue?@action=redirect&bpo=35800].)

The lib2to3 module now emits a PendingDeprecationWarning. Python 3.9 switched to a PEG parser (see PEP 617 [https://peps.python.org/pep-0617/]), and Python 3.10 may include new language syntax that is not parsable by lib2to3’s LL(1) parser. The lib2to3 module may be removed from the standard library in a future Python version. Consider third-party alternatives such as LibCST [https://libcst.readthedocs.io/] or parso [https://parso.readthedocs.io/]. (Contributed by Carl Meyer in bpo-40360 [https://bugs.python.org/issue?@action=redirect&bpo=40360].)

random.shuffle()의 random 매개 변수는 폐지되었습니다. (Contributed by Raymond Hettinger in bpo-40465 [https://bugs.python.org/issue?@action=redirect&bpo=40465])

제거

The erroneous version at unittest.mock.__version__ has been removed.

nntplib.NNTP: xpath() and xgtitle() methods have been removed. These methods are deprecated since Python 3.3. Generally, these extensions are not supported or not enabled by NNTP server administrators. For xgtitle(), please use nntplib.NNTP.descriptions() or nntplib.NNTP.description() instead. (Contributed by Donghee Na in bpo-39366 [https://bugs.python.org/issue?@action=redirect&bpo=39366].)

array.array: tostring()과 fromstring() 메서드가 제거되었습니다. 이것들은 tobytes()와 frombytes()의 별칭으로, 파이썬 3.2부터 폐지되었습니다. (Contributed by Victor Stinner in bpo-38916 [https://bugs.python.org/issue?@action=redirect&bpo=38916].)

설명되지 않은 sys.callstats() 함수가 제거되었습니다. 파이썬 3.7부터는, 폐지되었고 항상 None을 반환했습니다. 파이썬 3.7에서 이미 제거된 특수 빌드 옵션 CALL_PROFILE이 필요했습니다. (Contributed by Victor Stinner in bpo-37414 [https://bugs.python.org/issue?@action=redirect&bpo=37414].)

sys.getcheckinterval() 과 sys.setcheckinterval() 함수가 제거되었습니다. 파이썬 3.2부터 폐지되었습니다. 대신 sys.getswitchinterval()과 sys.setswitchinterval()을 사용하십시오. (Contributed by Victor Stinner in bpo-37392 [https://bugs.python.org/issue?@action=redirect&bpo=37392].)

C 함수 PyImport_Cleanup()이 제거되었습니다. 이렇게 설명되어 있었습니다: “모듈 테이블을 비웁니다. 내부 전용.” (Contributed by Victor Stinner in bpo-36710 [https://bugs.python.org/issue?@action=redirect&bpo=36710].)

_dummy_thread와 dummy_threading 모듈이 제거되었습니다. 이 모듈은 스레드 지원이 필수인 파이썬 3.7부터 폐지되었습니다. (Contributed by Victor Stinner in bpo-37312 [https://bugs.python.org/issue?@action=redirect&bpo=37312].)

aifc.openfp() alias to aifc.open(), sunau.openfp() alias to sunau.open(), and wave.openfp() alias to wave.open() have been removed. They were deprecated since Python 3.7. (Contributed by Victor Stinner in bpo-37320 [https://bugs.python.org/issue?@action=redirect&bpo=37320].)

The isAlive() method of threading.Thread has been removed. It was deprecated since Python 3.8. Use is_alive() instead. (Contributed by Donghee Na in bpo-37804 [https://bugs.python.org/issue?@action=redirect&bpo=37804].)

ElementTree 모듈에서 클래스 ElementTree와 Element의 메서드 getchildren()과 getiterator()가 제거되었습니다. 파이썬 3.2에서 폐지되었습니다. x.getchildren() 대신 iter(x)나 list(x)를, x.getiterator() 대신 x.iter()나 list(x.iter())를 사용하십시오. (Contributed by Serhiy Storchaka in bpo-36543 [https://bugs.python.org/issue?@action=redirect&bpo=36543].)

낡은 plistlib API는 제거되었습니다, 파이썬 3.4부터 폐지되었습니다. load(), loads(), dump() 및 dumps() 함수를 사용하십시오. 또한, use_builtin_types 매개 변수가 제거되었으며, 표준 bytes 객체가 항상 대신 사용됩니다. (Contributed by Jon Janzen in bpo-36409 [https://bugs.python.org/issue?@action=redirect&bpo=36409].)

C 함수 PyGen_NeedsFinalizing이 제거되었습니다. PEP 442 [https://peps.python.org/pep-0442/]를 구현한 후, 설명되지도, 테스트 되지도, CPython 내 어디에서건 사용되지도 않았습니다. Joannah Nanjekye의 패치. (Contributed by Joannah Nanjekye in bpo-15088 [https://bugs.python.org/issue?@action=redirect&bpo=15088])

파이썬 3.1부터 폐지된 별칭 base64.encodestring()과 base64.decodestring()은 제거되었습니다: 대신 base64.encodebytes()와 base64.decodebytes()를 사용하십시오. (Contributed by Victor Stinner in bpo-39351 [https://bugs.python.org/issue?@action=redirect&bpo=39351].)

fractions.gcd() 함수가 제거되었습니다, 파이썬 3.5부터 폐지되었습니다 (bpo-22486 [https://bugs.python.org/issue?@action=redirect&bpo=22486]): 대신 math.gcd()를 사용하십시오. (Contributed by Victor Stinner in bpo-39350 [https://bugs.python.org/issue?@action=redirect&bpo=39350].)

bz2.BZ2File의 buffering 매개 변수가 제거되었습니다. 파이썬 3.0부터 무시되었고 사용하면 DeprecationWarning을 방출했습니다. 파일을 여는 방법을 제어하려면 열린 파일 객체를 전달하십시오. (Contributed by Victor Stinner in bpo-39357 [https://bugs.python.org/issue?@action=redirect&bpo=39357].)

json.loads()의 encoding 매개 변수가 제거되었습니다. 파이썬 3.1부터 폐지되었고 무시되었습니다; 파이썬 3.8부터 사용하면 DeprecationWarning을 방출했습니다. (Contributed by Inada Naoki in bpo-39377 [https://bugs.python.org/issue?@action=redirect&bpo=39377])

with (await asyncio.lock):와 with (yield from asyncio.lock): 문은 더는 지원되지 않습니다, 대신 async with lock을 사용하십시오. asyncio.Condition과 asyncio.Semaphore도 마찬가지입니다. (Contributed by Andrew Svetlov in bpo-34793 [https://bugs.python.org/issue?@action=redirect&bpo=34793].)

The sys.getcounts() function, the -X showalloccount command line option and the show_alloc_count field of the C structure PyConfig have been removed. They required a special Python build by defining COUNT_ALLOCS macro. (Contributed by Victor Stinner in bpo-39489 [https://bugs.python.org/issue?@action=redirect&bpo=39489].)

typing.NamedTuple 클래스의 _field_types 어트리뷰트가 제거되었습니다. 파이썬 3.8부터 폐지되었습니다. 대신 __annotations__ 어트리뷰트를 사용하십시오. (Contributed by Serhiy Storchaka in bpo-40182 [https://bugs.python.org/issue?@action=redirect&bpo=40182].)

The symtable.SymbolTable.has_exec() method has been removed. It was deprecated since 2006, and only returning False when it’s called. (Contributed by Batuhan Taskaya in bpo-40208 [https://bugs.python.org/issue?@action=redirect&bpo=40208])

The asyncio.Task.current_task() and asyncio.Task.all_tasks() have been removed. They were deprecated since Python 3.7 and you can use asyncio.current_task() and asyncio.all_tasks() instead. (Contributed by Rémi Lapeyre in bpo-40967 [https://bugs.python.org/issue?@action=redirect&bpo=40967])

html.parser.HTMLParser 클래스의 unescape() 메서드가 제거되었습니다 (파이썬 3.4부터 폐지되었습니다). 문자 참조를 해당 유니코드 문자로 변환하는 데 html.unescape()를 사용해야 합니다.

파이썬 3.9로 이식하기

이 절에서는 여러분의 코드 수정을 요구할 수도 있는 이전에 설명한 변경 사항과 다른 버그 수정 사항을 나열합니다.

파이썬 API의 변경

__import__()와 importlib.util.resolve_name()은 이전에 ValueError를 발생시키던 곳에서 이제 ImportError를 발생시킵니다. 특정 예외 형을 포착하고 파이썬 3.9와 이전 버전을 모두 지원하는 호출자는 except (ImportError, ValueError):를 사용하여 둘 다 포착해야 합니다.

__VENV_PROMPT__가 ""로 설정될 때 venv 활성화 스크립트는 더는 특별한 경우가 아닙니다.

The select.epoll.unregister() method no longer ignores the EBADF error. (Contributed by Victor Stinner in bpo-39239 [https://bugs.python.org/issue?@action=redirect&bpo=39239].)

buffering 매개 변수가 제거되었기 때문에, bz2.BZ2File의 compresslevel 매개 변수는 키워드 전용이 되었습니다. (Contributed by Victor Stinner in bpo-39357 [https://bugs.python.org/issue?@action=redirect&bpo=39357].)

서브스크립션이 단순화된 AST. 단순 인덱스는 값으로 표시되고, 확장 슬라이스는 튜플로 표시됩니다. Index(value)는 value 자체를 반환하고, ExtSlice(slices)는 Tuple(slices, Load())를 반환합니다. (Contributed by Serhiy Storchaka in bpo-34822 [https://bugs.python.org/issue?@action=redirect&bpo=34822].)

-E나 -I 명령 줄 옵션을 사용할 때 importlib 모듈은 이제 PYTHONCASEOK 환경 변수를 무시합니다.

encoding 매개 변수가 클래스 ftplib.FTP와 ftplib.FTP_TLS에 키워드 전용 매개 변수로 추가되었으며, 기본 인코딩이 RFC 2640 [https://datatracker.ietf.org/doc/html/rfc2640.html]을 따르도록 Latin-1에서 UTF-8로 변경되었습니다.

asyncio.loop.shutdown_default_executor()가 AbstractEventLoop 에 추가되어서, 이것을 상속하는 대체 이벤트 루프에 이 메서드가 정의되어 있어야 합니다. (Contributed by Kyle Stanley in bpo-34037 [https://bugs.python.org/issue?@action=redirect&bpo=34037].)

컴파일러 플래그와의 충돌을 방지하기 위해 __future__ 모듈에서 퓨처 플래그의 상숫값이 갱신되었습니다. 이전에는 PyCF_ALLOW_TOP_LEVEL_AWAIT가 CO_FUTURE_DIVISION과 충돌했습니다. (Contributed by Batuhan Taskaya in bpo-39562 [https://bugs.python.org/issue?@action=redirect&bpo=39562])

array('u') now uses wchar_t as C type instead of Py_UNICODE. This change doesn’t affect to its behavior because Py_UNICODE is alias of wchar_t since Python 3.3. (Contributed by Inada Naoki in bpo-34538 [https://bugs.python.org/issue?@action=redirect&bpo=34538].)

logging.getLogger() API는 이제 이름 'root'를 전달할 때 루트 로거를 반환합니다. 이전에는 'root'라는 이름의 비 루트 로거를 반환했습니다. 이것은 사용자 코드가 'root'라는 이름의 루트가 아닌 로거를 명시적으로 원하거나, 'root.py'라는 최상위 모듈에서 logging.getLogger(__name__)을 사용하여 로거를 인스턴스 화하는 경우에 영향을 미칠 수 있습니다. (Contributed by Vinay Sajip in bpo-37742 [https://bugs.python.org/issue?@action=redirect&bpo=37742].)

Division handling of PurePath now returns NotImplemented instead of raising a TypeError when passed something other than an instance of str or PurePath. This allows creating compatible classes that don’t inherit from those mentioned types. (Contributed by Roger Aiudi in bpo-34775 [https://bugs.python.org/issue?@action=redirect&bpo=34775]).

Starting with Python 3.9.5 the ipaddress module no longer accepts any leading zeros in IPv4 address strings. Leading zeros are ambiguous and interpreted as octal notation by some libraries. For example the legacy function socket.inet_aton() treats leading zeros as octal notatation. glibc implementation of modern inet_pton() does not accept any leading zeros. (Contributed by Christian Heimes in bpo-36384 [https://bugs.python.org/issue?@action=redirect&bpo=36384]).

codecs.lookup() now normalizes the encoding name the same way as encodings.normalize_encoding(), except that codecs.lookup() also converts the name to lower case. For example, "latex+latin1" encoding name is now normalized to "latex_latin1". (Contributed by Jordon Xu in bpo-37751 [https://bugs.python.org/issue?@action=redirect&bpo=37751].)

C API의 변경

Instances of heap-allocated types (such as those created with PyType_FromSpec() and similar APIs) hold a reference to their type object since Python 3.8. As indicated in the “Changes in the C API” of Python 3.8, for the vast majority of cases, there should be no side effect but for types that have a custom tp_traverse function, ensure that all custom tp_traverse functions of heap-allocated types visit the object’s type.

예:

int
foo_traverse(foo_struct *self, visitproc visit, void *arg) {
// Rest of the traverse function
#if PY_VERSION_HEX >= 0x03090000
    // This was not needed before Python 3.9 (Python issue 35810 and 40217)
    Py_VISIT(Py_TYPE(self));
#endif
}

If your traverse function delegates to tp_traverse of its base class (or another type), ensure that Py_TYPE(self) is visited only once. Note that only heap type are expected to visit the type in tp_traverse.

예를 들어, tp_traverse 함수가 다음을 포함하면:

base->tp_traverse(self, visit, arg)

다음을 추가하십시오:

#if PY_VERSION_HEX >= 0x03090000
    // This was not needed before Python 3.9 (bpo-35810 and bpo-40217)
    if (base->tp_flags & Py_TPFLAGS_HEAPTYPE) {
        // a heap type's tp_traverse already visited Py_TYPE(self)
    } else {
        Py_VISIT(Py_TYPE(self));
    }
#else

(자세한 내용은 bpo-35810 [https://bugs.python.org/issue?@action=redirect&bpo=35810]과 bpo-40217 [https://bugs.python.org/issue?@action=redirect&bpo=40217]을 참조하십시오.)

PyEval_CallObject, PyEval_CallFunction, PyEval_CallMethod 및 PyEval_CallObjectWithKeywords 함수는 폐지되었습니다. 대신 PyObject_Call()과 그 변형을 사용하십시오. (자세한 내용은 bpo-29548 [https://bugs.python.org/issue?@action=redirect&bpo=29548]을 참조하십시오.)

CPython 바이트 코드 변경

The LOAD_ASSERTION_ERROR opcode was added for handling the assert statement. Previously, the assert statement would not work correctly if the AssertionError exception was being shadowed. (Contributed by Zackery Spytz in bpo-34880 [https://bugs.python.org/issue?@action=redirect&bpo=34880].)

COMPARE_OP 옵코드는 4개의 개별 명령어로 분할되었습니다:

풍부한 비교를 위한 COMPARE_OP

‘is’와 ‘is not’ 테스트를 위한 IS_OP

‘in’과 ‘not in’ 테스트를 위한 CONTAINS_OP

‘try-except’ 문에서 예외를 확인하기 위한 JUMP_IF_NOT_EXC_MATCH.

(Contributed by Mark Shannon in bpo-39156 [https://bugs.python.org/issue?@action=redirect&bpo=39156].)

빌드 변경

Added --with-platlibdir option to the configure script: name of the platform-specific library directory, stored in the new sys.platlibdir attribute. See sys.platlibdir attribute for more information. (Contributed by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner in bpo-1294959 [https://bugs.python.org/issue?@action=redirect&bpo=1294959].)

COUNT_ALLOCS 특수 빌드 매크로가 제거되었습니다. (Contributed by Victor Stinner in bpo-39489 [https://bugs.python.org/issue?@action=redirect&bpo=39489].)

On non-Windows platforms, the setenv() and unsetenv() functions are now required to build Python. (Contributed by Victor Stinner in bpo-39395 [https://bugs.python.org/issue?@action=redirect&bpo=39395].)

윈도우가 아닌 플랫폼에서, bdist_wininst 설치 프로그램 생성은 이제 공식적으로 지원되지 않습니다. (자세한 내용은 bpo-10945 [https://bugs.python.org/issue?@action=redirect&bpo=10945]를 참조하십시오.)

When building Python on macOS from source, _tkinter now links with non-system Tcl and Tk frameworks if they are installed in /Library/Frameworks, as had been the case on older releases of macOS. If a macOS SDK is explicitly configured, by using --enable-universalsdk or -isysroot, only the SDK itself is searched. The default behavior can still be overridden with --with-tcltk-includes and --with-tcltk-libs. (Contributed by Ned Deily in bpo-34956 [https://bugs.python.org/issue?@action=redirect&bpo=34956].)

이제 윈도우 10 ARM64 용으로 파이썬을 빌드할 수 있습니다. (Contributed by Steve Dower in bpo-33125 [https://bugs.python.org/issue?@action=redirect&bpo=33125].)

--pgo를 사용할 때 이제 일부 개별 테스트를 건너뜁니다. 문제의 테스트는 PGO 작업 시간을 매우 증가시켰으며 최종 실행 파일의 최적화를 개선하는 데 도움이 되지 않았을 가능성이 높습니다. 이렇게 하면 작업 속도가 약 15배 빨라집니다. 전체 단위 테스트 스위트를 실행하는 것은 느립니다. 이 변경으로 인해 많은 코드 분기가 실행되지 않아서 빌드가 약간 덜 최적화 될 수 있습니다. 훨씬 느린 빌드를 기다릴 의사가 있다면, ./configure [..] PROFILE_TASK="-m test --pgo-extended"를 사용하여 이전 동작을 복원할 수 있습니다. 우리는 어떤 PGO 작업 집합이 더 빠른 빌드를 생성하는지에 대해 보장하지 않습니다. 결과가 환경, 워크로드 및 컴파일러 도구 체인에 따라 달라질 수 있어서, 이를 중요하게 생각하는 사용자는 자신의 관련 벤치마크를 실행해야 합니다. (자세한 내용은 bpo-36044 [https://bugs.python.org/issue?@action=redirect&bpo=36044]와 bpo-37707 [https://bugs.python.org/issue?@action=redirect&bpo=37707]를 참조하십시오.)

C API 변경

새로운 기능

PEP 573 [https://peps.python.org/pep-0573/]: Added PyType_FromModuleAndSpec() to associate a module with a class; PyType_GetModule() and PyType_GetModuleState() to retrieve the module and its state; and PyCMethod and METH_METHOD to allow a method to access the class it was defined in. (Contributed by Marcel Plch and Petr Viktorin in bpo-38787 [https://bugs.python.org/issue?@action=redirect&bpo=38787].)

PyFrame_GetCode() 함수를 추가했습니다: 프레임 코드를 얻습니다. PyFrame_GetBack() 함수를 추가했습니다: 프레임 다음 외부 프레임을 얻습니다. (Contributed by Victor Stinner in bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421].)

제한된 C API에 PyFrame_GetLineNumber()를 추가했습니다. (Contributed by Victor Stinner in bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421].)

인터프리터를 얻는 PyThreadState_GetInterpreter()와 PyInterpreterState_Get() 함수를 추가했습니다. 파이썬 스레드 상태의 현재 프레임을 가져오는 PyThreadState_GetFrame() 함수를 추가했습니다. PyThreadState_GetID() 함수를 추가했습니다: 파이썬 스레드 상태의 고유 식별자를 가져옵니다. (Contributed by Victor Stinner in bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947].)

인자 없이 콜러블 파이썬 객체를 호출하는 새로운 공용 PyObject_CallNoArgs() 함수를 C API에 추가했습니다. 인자 없이 콜러블 파이썬 객체를 호출하는 가장 효율적인 방법입니다. (Contributed by Victor Stinner in bpo-37194 [https://bugs.python.org/issue?@action=redirect&bpo=37194].)

제한된 C API의 변경 사항 (Py_LIMITED_API 매크로가 정의된 경우):

제한된 API에 대한 일반 함수로 Py_EnterRecursiveCall() 과 Py_LeaveRecursiveCall() 을 제공합니다. 이전에는, 이들이 매크로로 정의되었지만, 이러한 매크로는 PyThreadState.recursion_depth 필드에 액세스할 수 없는 제한된 C API로는 컴파일되지 않았습니다 (이 구조체는 제한된 C API에서 불투명합니다).

PyObject_INIT()와 PyObject_INIT_VAR()는 구현 세부 정보를 숨기도록 일반 “불투명” 함수가 됩니다.

(Contributed by Victor Stinner in bpo-38644 [https://bugs.python.org/issue?@action=redirect&bpo=38644] and bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542].)

The PyModule_AddType() function is added to help adding a type to a module. (Contributed by Donghee Na in bpo-40024 [https://bugs.python.org/issue?@action=redirect&bpo=40024].)

PyObject_GC_IsTracked()와 PyObject_GC_IsFinalized() 함수를 공용 API에 추가하여 파이썬 객체가 현재 추적되고 있거나 가비지 수거기에 의해 이미 파이널라이즈 되었는지 조회할 수 있습니다. (Contributed by Pablo Galindo Salgado in bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241].)

Added _PyObject_FunctionStr() to get a user-friendly string representation of a function-like object. (Patch by Jeroen Demeyer in bpo-37645 [https://bugs.python.org/issue?@action=redirect&bpo=37645].)

하나의 위치 인자로 객체를 호출하는 PyObject_CallOneArg()를 추가했습니다 (Patch by Jeroen Demeyer in bpo-37483 [https://bugs.python.org/issue?@action=redirect&bpo=37483].)

파이썬 3.9로 이식하기

PyInterpreterState.eval_frame(PEP 523 [https://peps.python.org/pep-0523/])에는 이제 새로운 필수 tstate 매개 변수(PyThreadState*)가 필요합니다. (Contributed by Victor Stinner in bpo-38500 [https://bugs.python.org/issue?@action=redirect&bpo=38500].)

확장 모듈: 모듈 상태가 요청되었지만, 아직 할당되지 않았으면 PyModuleDef의 m_traverse, m_clear 및 m_free 함수가 더는 호출되지 않습니다. 이것은 모듈이 만들이진 직후, 모듈이 실행되기 직전의 경우입니다 (Py_mod_exec 함수). 더 정확하게는, m_size가 0보다 크고 모듈 상태(PyModule_GetState()가 반환하는)가 NULL이면 이 함수가 호출되지 않습니다.

모듈 상태가 없는 확장 모듈(m_size <= 0)은 영향을 받지 않습니다.

서브 인터프리터에서 Py_AddPendingCall() 이 호출되면, 함수는 이제 메인 인터프리터에서 호출되지 않고 서브 인터프리터에서 호출되도록 예약됩니다. 각 서브 인터프리터는 이제 자체 예약된 호출 목록을 갖습니다. (Contributed by Victor Stinner in bpo-39984 [https://bugs.python.org/issue?@action=redirect&bpo=39984].)

-E 옵션이 사용될 때 (PyConfig.use_environment가 0으로 설정될 때) 윈도우 레지스트리가 더는 sys.path를 초기화하는 데 사용되지 않습니다. 이것은 윈도우에서 파이썬을 내장할 때 중요합니다. (Contributed by Zackery Spytz in bpo-8901 [https://bugs.python.org/issue?@action=redirect&bpo=8901].)

전역 변수 PyStructSequence_UnnamedField는 이제 상수이며 상수 문자열을 참조합니다. (Contributed by Serhiy Storchaka in bpo-38650 [https://bugs.python.org/issue?@action=redirect&bpo=38650].)

The PyGC_Head structure is now opaque. It is only defined in the internal C API (pycore_gc.h). (Contributed by Victor Stinner in bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241].)

The Py_UNICODE_COPY, Py_UNICODE_FILL, PyUnicode_WSTR_LENGTH, PyUnicode_FromUnicode(), PyUnicode_AsUnicode(), _PyUnicode_AsUnicode, and PyUnicode_AsUnicodeAndSize() are marked as deprecated in C. They have been deprecated by PEP 393 [https://peps.python.org/pep-0393/] since Python 3.3. (Contributed by Inada Naoki in bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346].)

Py_FatalError() 함수는, Py_LIMITED_API 매크로가 정의되지 않는 한, 현재 함수의 이름을 자동으로 로그 하는 매크로로 대체됩니다. (Contributed by Victor Stinner in bpo-39882 [https://bugs.python.org/issue?@action=redirect&bpo=39882].)

벡터콜 프로토콜은 이제 호출자가 키워드 이름으로 문자열만 전달하도록 요구합니다. (자세한 내용은 bpo-37540 [https://bugs.python.org/issue?@action=redirect&bpo=37540]을 참조하십시오.)

이제 여러 매크로와 함수의 구현 세부 사항이 숨겨집니다:

PyObject_IS_GC() 매크로가 함수로 변환되었습니다.

The PyObject_NEW() macro becomes an alias to the PyObject_New macro, and the PyObject_NEW_VAR() macro becomes an alias to the PyObject_NewVar macro. They no longer access directly the PyTypeObject.tp_basicsize member.

PyObject_GET_WEAKREFS_LISTPTR() macro was converted to a function: the macro accessed directly the PyTypeObject.tp_weaklistoffset member.

PyObject_CheckBuffer() 매크로가 함수로 변환되었습니다: 매크로는 PyTypeObject.tp_as_buffer 멤버에 직접 액세스했습니다.

PyIndex_Check()는 이제 구현 세부 사항을 숨기기 위해 항상 불투명한 함수로 선언됩니다: PyIndex_Check() 매크로가 제거되었습니다. 매크로는 PyTypeObject.tp_as_number 멤버에 직접 액세스했습니다.

(자세한 내용은 bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]을 참조하십시오.)

제거

제한된 C API에서 pyfpe.h의 PyFPE_START_PROTECT()와 PyFPE_END_PROTECT() 매크로를 제외했습니다. (Contributed by Victor Stinner in bpo-38835 [https://bugs.python.org/issue?@action=redirect&bpo=38835].)

PyTypeObject의 tp_print 슬롯이 제거되었습니다. 파이썬 2.7과 이전 버전에서 파일로 객체를 인쇄하는 데 사용되었습니다. 파이썬 3.0부터는, 무시되고 사용되지 않았습니다. (Contributed by Jeroen Demeyer in bpo-36974 [https://bugs.python.org/issue?@action=redirect&bpo=36974].)

제한된 C API의 변경 사항 (Py_LIMITED_API 매크로가 정의된 경우):

제한된 C API에서 다음 함수를 제외했습니다:

PyThreadState_DeleteCurrent() (Contributed by Joannah Nanjekye in bpo-37878 [https://bugs.python.org/issue?@action=redirect&bpo=37878].)

_Py_CheckRecursionLimit

_Py_NewReference()

_Py_ForgetReference()

_PyTraceMalloc_NewReference()

_Py_GetRefTotal()

제한된 C API에서 결코 작동하지 않은 휴지통 메커니즘.

PyTrash_UNWIND_LEVEL

Py_TRASHCAN_BEGIN_CONDITION

Py_TRASHCAN_BEGIN

Py_TRASHCAN_END

Py_TRASHCAN_SAFE_BEGIN

Py_TRASHCAN_SAFE_END

다음 함수와 정의를 내부 C API로 옮겼습니다:

_PyDebug_PrintTotalRefs()

_Py_PrintReferences()

_Py_PrintReferenceAddresses()

_Py_tracemalloc_config

_Py_AddToAllObjects() (Py_TRACE_REFS 빌드에만 해당)

(Contributed by Victor Stinner in bpo-38644 [https://bugs.python.org/issue?@action=redirect&bpo=38644] and bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542].)

_PyRuntime.getframe 훅을 제거했고 _PyRuntime.getframe의 별칭인 _PyThreadState_GetFrame 매크로를 제거했습니다. 이들은 내부 C API에 의해서만 노출되었습니다. PyThreadFrameGetter 형도 제거했습니다. (Contributed by Victor Stinner in bpo-39946 [https://bugs.python.org/issue?@action=redirect&bpo=39946].)

C API에서 다음 함수를 제거했습니다. 모든 자유 목록을 지우려면 PyGC_Collect()를 명시적으로 호출하십시오. (Contributed by Inada Naoki and Victor Stinner in bpo-37340 [https://bugs.python.org/issue?@action=redirect&bpo=37340], bpo-38896 [https://bugs.python.org/issue?@action=redirect&bpo=38896] and bpo-40428 [https://bugs.python.org/issue?@action=redirect&bpo=40428].)

PyAsyncGen_ClearFreeLists()

PyContext_ClearFreeList()

PyDict_ClearFreeList()

PyFloat_ClearFreeList()

PyFrame_ClearFreeList()

PyList_ClearFreeList()

PyMethod_ClearFreeList()와 PyCFunction_ClearFreeList(): 연결된 메서드 객체의 자유 목록이 제거되었습니다.

PySet_ClearFreeList(): 파이썬 3.4에서 집합 자유 목록이 제거되었습니다.

PyTuple_ClearFreeList()

PyUnicode_ClearFreeList(): 파이썬 3.3에서 유니코드 자유 목록이 제거되었습니다.

_PyUnicode_ClearStaticStrings() 함수를 제거했습니다. (Contributed by Victor Stinner in bpo-39465 [https://bugs.python.org/issue?@action=redirect&bpo=39465].)

Py_UNICODE_MATCH를 제거했습니다. PEP 393 [https://peps.python.org/pep-0393/]에서 폐지되었고, 파이썬 3.3부터 망가졌습니다. 대신 PyUnicode_Tailmatch() 함수를 사용할 수 있습니다. (Contributed by Inada Naoki in bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346].)

정의되었지만 구현이 없는 헤더 파일들을 정리했습니다. 제거되는 공용 API 심볼은: _PyBytes_InsertThousandsGroupingLocale, _PyBytes_InsertThousandsGrouping, _Py_InitializeFromArgs, _Py_InitializeFromWideArgs, _PyFloat_Repr, _PyFloat_Digits, _PyFloat_DigitsInit, PyFrame_ExtendStack, _PyAIterWrapper_Type, PyNullImporter_Type, PyCmpWrapper_Type, PySortWrapper_Type, PyNoArgsFunction입니다. (Contributed by Pablo Galindo Salgado in bpo-39372 [https://bugs.python.org/issue?@action=redirect&bpo=39372].)

파이썬 3.9.1의 주목할만한 변경 사항

typing

typing.Literal의 동작은 PEP 586 [https://peps.python.org/pep-0586/]를 따르고 PEP에 지정된 정적 형 검사기의 동작과 일치하도록 변경되었습니다.

Literal은 이제 매개 변수를 중복 제거합니다.

Literal 객체 간의 동등 비교는 이제 순서에 독립적입니다.

Literal 비교는 이제 형을 존중합니다. 예를 들어, Literal[0] == Literal[False]는 이전에 True로 평가되었습니다. 이제 False입니다. 이 변경을 지원하기 위해, 내부적으로 사용되는 형 캐시는 이제 형 구분을 지원합니다.

Literal objects will now raise a TypeError exception during equality comparisons if any of their parameters are not hashable. Note that declaring Literal with mutable parameters will not throw an error:

>>> from typing import Literal
>>> Literal[{0}]
>>> Literal[{0}] == Literal[{False}]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'set'

(Contributed by Yurii Karabas in bpo-42345 [https://bugs.python.org/issue?@action=redirect&bpo=42345].)

macOS 11.0 (Big Sur) 및 Apple Silicon Mac 지원

3.9.1부터, 파이썬은 이제 macOS 11.0 (Big Sur)과 Apple Silicon Mac(ARM64 아키텍처 기반)에서 빌드와 실행을 완전히 지원합니다. 이제 새로운 유니버설 빌드 변형인 universal2를 사용하여 하나의 실행 파일 집합에서 ARM64와 Intel 64를 모두 네이티브 하게 지원할 수 있습니다. 바이너리는 이제 현재 버전의 macOS에서 빌드되어 다양한 이전 macOS 버전(10.9까지 테스트 되었습니다)에 배포되는 동시에 실행시간에 사용 중인 운영 체제 버전에 따라 조건부로 사용 가능한 일부 새로운 OS 기능과 옵션을 만들 수 있습니다 (“약한 링크(weaklinking)”).

(Contributed by Ronald Oussoren and Lawrence D’Anna in bpo-41100 [https://bugs.python.org/issue?@action=redirect&bpo=41100].)

파이썬 3.9.2의 주목할만한 변경 사항

collections.abc

collections.abc.Callable 제네릭은 이제 typing.Callable이 현재 수행하는 것과 유사하게 형 매개 변수를 평활화합니다. 이것은 collections.abc.Callable[[int, str], str]의 __args__가 (int, str, str)임을 의미합니다; 이전에는 ([int, str], str)였습니다. 이러한 변경을 허용하기 위해, 이제 types.GenericAlias를 서브 클래싱할 수 있으며, collections.abc.Callable 형을 서브스크립팅할 할 때 서브 클래스가 반환됩니다. typing.get_args()나 __args__를 통해 인자에 액세스하는 코드는 이 변경 사항을 고려해야 합니다. 파이썬 3.9.1에서 조용히 전달되었을 수 있는 collections.abc.Callable의 유효하지 않은 매개 변수화 형식에 대해 DeprecationWarning을 방출할 수 있습니다. 이 DeprecationWarning은 파이썬 3.10에서 TypeError가 됩니다. (Contributed by Ken Jin in bpo-42195 [https://bugs.python.org/issue?@action=redirect&bpo=42195].)

urllib.parse

Earlier Python versions allowed using both ; and & as query parameter separators in urllib.parse.parse_qs() and urllib.parse.parse_qsl(). Due to security concerns, and to conform with newer W3C recommendations, this has been changed to allow only a single separator key, with & as the default. This change also affects cgi.parse() and cgi.parse_multipart() as they use the affected functions internally. For more details, please see their respective documentation. (Contributed by Adam Goldschmidt, Senthil Kumaran and Ken Jin in bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967].)

파이썬 3.9.3의 주목할만한 변경 사항

A security fix alters the ftplib.FTP behavior to not trust the IPv4 address sent from the remote server when setting up a passive data channel. We reuse the ftp server IP address instead. For unusual code requiring the old behavior, set a trust_server_pasv_ipv4_address attribute on your FTP instance to True. (See gh-87451 [https://github.com/python/cpython/issues/87451])

Notable changes in Python 3.9.5

urllib.parse

The presence of newline or tab characters in parts of a URL allows for some forms of attacks. Following the WHATWG specification that updates RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html], ASCII newline \n, \r and tab \t characters are stripped from the URL by the parser in urllib.parse preventing such attacks. The removal characters are controlled by a new module level variable urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE. (See gh-88048 [https://github.com/python/cpython/issues/88048])

Notable security feature in 3.9.14

Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735]. This limit can be configured or disabled by environment variable, command line flag, or sys APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.

Notable changes in 3.9.17

tarfile

The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details. In Python 3.12, use without the filter argument will show a DeprecationWarning. In Python 3.14, the default will switch to 'data'. (Contributed by Petr Viktorin in PEP 706 [https://peps.python.org/pep-0706/].)

파이썬 3.8의 새로운 기능

편집자:

Raymond Hettinger

This article explains the new features in Python 3.8, compared to 3.7. Python 3.8 was released on October 14, 2019. For full details, see the changelog.

요약 – 배포 주요 사항

새로운 기능

대입 표현식

더 큰 표현식의 일부로 변수에 값을 대입하는 새로운 문법 := 이 있습니다. 바다코끼리의 눈과 엄니 [https://en.wikipedia.org/wiki/Walrus#/media/File:Pacific_Walrus_-_Bull_(8247646168).jpg]를 닮아서 “바다코끼리 연산자(the walrus operator)”라고 친근하게 알려져 있습니다.

이 예에서, 대입 표현식은 len()을 두 번 호출하지 않도록 합니다:

if (n := len(a)) > 10:
    print(f"List is too long ({n} elements, expected <= 10)")

정규식 일치 중에도 비슷한 이점이 있습니다. 일치 객체가 두 번 필요합니다, 일치하는지 검사할 때 한 번, 서브 그룹을 추출할 때 한 번:

discount = 0.0
if (mo := re.search(r'(\d+)% discount', advertisement)):
    discount = float(mo.group(1)) / 100.0

이 연산자는 루프 종료를 검사하기 위해 값을 계산한 다음 루프의 바디에서 그 값이 다시 필요한 while 루프에도 유용합니다:

# Loop over fixed length blocks
while (block := f.read(256)) != '':
    process(block)

필터링 조건에서 계산된 값이 표현식 바디에도 필요한 리스트 컴프리헨션에서 또 다른 사용 사례가 생깁니다:

[clean_name.title() for name in names
 if (clean_name := normalize('NFC', name)) in allowed_names]

복잡성을 줄이고 가독성을 개선하는 명확한 사례로 바다코끼리 연산자 사용을 제한하십시오.

자세한 설명은 PEP 572 [https://peps.python.org/pep-0572/]를 참조하십시오.

(Contributed by Emily Morehouse in bpo-35224 [https://bugs.python.org/issue?@action=redirect&bpo=35224].)

위치 전용 매개 변수

There is a new function parameter syntax / to indicate that some function parameters must be specified positionally and cannot be used as keyword arguments. This is the same notation shown by help() for C functions annotated with Larry Hastings’ Argument Clinic [https://devguide.python.org/development-tools/clinic/] tool.

다음 예에서, 매개 변수 a와 b는 위치 전용이며, c나 d는 위치나 키워드일 수 있으며, e나 f는 키워드 전용이어야 합니다:

def f(a, b, /, c, d, *, e, f):
    print(a, b, c, d, e, f)

다음은 유효한 호출입니다:

f(10, 20, 30, d=40, e=50, f=60)

하지만, 다음은 잘못된 호출입니다:

f(10, b=20, c=30, d=40, e=50, f=60)   # b cannot be a keyword argument
f(10, 20, 30, 40, 50, f=60)           # e must be a keyword argument

이 표기법의 한 가지 사용 사례는 순수 파이썬 함수가 기존 C 코드 함수의 동작을 완전히 흉내 낼 수 있다는 것입니다. 예를 들어, 내장 divmod() 함수는 키워드 인자를 허용하지 않습니다:

def divmod(a, b, /):
    "Emulate the built in divmod() function"
    return (a // b, a % b)

또 다른 사용 사례는 매개 변수 이름이 도움이 되지 않을 때 키워드 인자를 배제하는 것입니다. 예를 들어, 내장 len() 함수의 서명은 len(obj, /)입니다. 이것은 다음과 같은 어색한 호출을 금지합니다:

len(obj='hello')  # The "obj" keyword argument impairs readability

매개 변수를 위치 전용으로 표시하면 클라이언트 코드를 손상할 위험 없이 매개 변수 이름을 나중에 변경할 수 있다는 추가적인 이점이 있습니다. 예를 들어, statistics 모듈에서, 매개 변수 이름 dist는 나중에 변경될 수 있습니다. 이것은 다음과 같은 함수 명세 때문에 가능해졌습니다:

def quantiles(dist, /, *, n=4, method='exclusive')
    ...

/의 왼쪽에 있는 매개 변수는 가능한 키워드로 노출되지 않기 때문에, 매개 변수 이름은 **kwargs에서 계속 사용할 수 있습니다:

>>> def f(a, b, /, **kwargs):
...     print(a, b, kwargs)
...
>>> f(10, 20, a=1, b=2, c=3)         # a and b are used in two ways
10 20 {'a': 1, 'b': 2, 'c': 3}

이는 임의의 키워드 인자를 받아들여야 하는 함수와 메서드의 구현을 크게 단순화합니다. 예를 들어, 다음은 collections 모듈의 코드에서 뽑아온 것입니다:

class Counter(dict):

    def __init__(self, iterable=None, /, **kwds):
        # Note "iterable" is a possible keyword argument

자세한 설명은 PEP 570 [https://peps.python.org/pep-0570/]을 참조하십시오.

(Contributed by Pablo Galindo in bpo-36540 [https://bugs.python.org/issue?@action=redirect&bpo=36540].)

컴파일된 바이트 코드 파일을 위한 병렬 파일 시스템 캐시

새 PYTHONPYCACHEPREFIX 설정(-X pycache_prefix로도 사용 가능합니다)은 각 소스 디렉터리 내의 기본 __pycache__ 하위 디렉터리 대신 별도의 병렬 파일 시스템 트리를 사용하도록 묵시적 바이트 코드 캐시를 구성합니다.

캐시의 위치는 sys.pycache_prefix로 보고됩니다 (None은 __pycache__ 하위 디렉터리의 기본 위치를 나타냅니다).

(Contributed by Carl Meyer in bpo-33499 [https://bugs.python.org/issue?@action=redirect&bpo=33499].)

디버그 빌드는 릴리스 빌드와 같은 ABI를 사용합니다.

파이썬은 이제 릴리스나 디버그 모드 중 어느 것으로 빌드되더라도 같은 ABI를 사용합니다. 유닉스에서, 파이썬이 디버그 모드로 빌드될 때, 이제 릴리스 모드로 빌드된 C 확장과 안정(stable) ABI를 사용해서 빌드된 C 확장을 로드할 수 있습니다.

Release builds and debug builds are now ABI compatible: defining the Py_DEBUG macro no longer implies the Py_TRACE_REFS macro, which introduces the only ABI incompatibility. The Py_TRACE_REFS macro, which adds the sys.getobjects() function and the PYTHONDUMPREFS environment variable, can be set using the new ./configure --with-trace-refs build option. (Contributed by Victor Stinner in bpo-36465 [https://bugs.python.org/issue?@action=redirect&bpo=36465].)

유닉스에서, C 확장은 안드로이드와 Cygwin을 제외하고는 더는 libpython에 링크되지 않습니다. 이제 정적으로 링크된 파이썬이 공유 라이브러리 파이썬을 사용하여 빌드된 C 확장을 로드할 수 있습니다. (Contributed by Victor Stinner in bpo-21536 [https://bugs.python.org/issue?@action=redirect&bpo=21536].)

유닉스에서, 파이썬이 디버그 모드로 빌드될 때, 임포트는 이제 릴리스 모드로 컴파일된 C 확장과 안정(stable) ABI로 컴파일된 C 확장도 찾습니다. (Contributed by Victor Stinner in bpo-36722 [https://bugs.python.org/issue?@action=redirect&bpo=36722].)

파이썬을 응용 프로그램에 내장하려면, 새로운 --embed 옵션을 python3-config --libs --embed에 전달하여 -lpython3.8을 얻어야 합니다 (응용 프로그램을 libpython에 링크합니다). 3.8 이하를 모두 지원하려면, 먼저 python3-config --libs --embed를 시도하고, 실패하면 python3-config --libs(--embed 없이)로 대체하십시오.

파이썬을 응용 프로그램에 내장하기 위해, pkg-config python-3.8-embed 모듈을 추가했습니다: pkg-config python-3.8-embed --libs 는 -lpython3.8을 포함합니다. 3.8 이하를 모두 지원하려면, 먼저 pkg-config python-X.Y-embed --libs 를 시도하고, 실패하면 pkg-config python-X.Y --libs(--embed 없이)로 대체하십시오 (X.Y를 파이썬 버전으로 교체하십시오).

반면에, pkg-config python3.8 --libs 는 더는 -lpython3.8을 포함하지 않습니다. C 확장은 libpython에 링크되어서는 안 됩니다 (안드로이드와 Cygwin은 예외인데, 이들은 스크립트로 처리됩니다); 이 변경은 의도적으로 이전 버전과 호환되지 않습니다. (Contributed by Victor Stinner in bpo-36721 [https://bugs.python.org/issue?@action=redirect&bpo=36721].)

f-문자열은 스스로 설명하는 표현식과 디버깅을 위해 =를 지원합니다.

f-문자열에 = 지정자를 추가했습니다. f'{expr=}'과 같은 f-문자열은 표현식의 텍스트, 등호, 평가된 표현식의 표현(repr)으로 확장됩니다. 예를 들어:

>>> user = 'eric_idle'
>>> member_since = date(1975, 7, 31)
>>> f'{user=} {member_since=}'
"user='eric_idle' member_since=datetime.date(1975, 7, 31)"

일반적인 f-문자열 포맷 지정자를 사용하면 표현식의 결과가 표시되는 방식을 더 잘 제어할 수 있습니다:

>>> delta = date.today() - member_since
>>> f'{user=!s}  {delta.days=:,d}'
'user=eric_idle  delta.days=16,075'

= 지정자는 계산을 표시할 수 있도록 전체 표현식을 표시합니다:

>>> print(f'{theta=}  {cos(radians(theta))=:.3f}')
theta=30  cos(radians(theta))=0.866

(Contributed by Eric V. Smith and Larry Hastings in bpo-36817 [https://bugs.python.org/issue?@action=redirect&bpo=36817].)

PEP 578: 파이썬 런타임 감사 훅

이 PEP는 감사 훅(Audit Hook)과 확인된 열기 훅(Verified Open Hook)을 추가합니다. 둘 다 파이썬과 네이티브 코드에서 사용 가능해서, 순수 파이썬 코드로 작성된 응용 프로그램과 프레임워크가 추가 알림을 활용할 수 있도록 함과 동시에 임베더(embedder)나 시스템 관리자가 감사가 항상 활성화된 파이썬 빌드를 배치할 수 있도록 합니다.

자세한 설명은 PEP 578 [https://peps.python.org/pep-0578/]을 참조하십시오.

PEP 587: 파이썬 초기화 구성

PEP 587 [https://peps.python.org/pep-0587/]은 파이썬 초기화를 구성하는 새로운 C API를 추가하여 전체 구성에 대한 세밀한 제어와 개선된 에러 보고를 제공합니다.

새로운 구조체:

PyConfig

PyPreConfig

PyStatus

PyWideStringList

새로운 함수:

PyConfig_Clear()

PyConfig_InitIsolatedConfig()

PyConfig_InitPythonConfig()

PyConfig_Read()

PyConfig_SetArgv()

PyConfig_SetBytesArgv()

PyConfig_SetBytesString()

PyConfig_SetString()

PyPreConfig_InitIsolatedConfig()

PyPreConfig_InitPythonConfig()

PyStatus_Error()

PyStatus_Exception()

PyStatus_Exit()

PyStatus_IsError()

PyStatus_IsExit()

PyStatus_NoMemory()

PyStatus_Ok()

PyWideStringList_Append()

PyWideStringList_Insert()

Py_BytesMain()

Py_ExitStatusException()

Py_InitializeFromConfig()

Py_PreInitialize()

Py_PreInitializeFromArgs()

Py_PreInitializeFromBytesArgs()

Py_RunMain()

이 PEP는 이러한 내부 구조체에 _PyRuntimeState.preconfig(PyPreConfig 형)와 PyInterpreterState.config (PyConfig 형) 필드를 추가합니다. PyInterpreterState.config는 전역 구성 변수와 기타 내부(private) 변수를 대체하는 새로운 참조 구성이 됩니다.

설명서는 파이썬 초기화 구성을 참조하십시오.

자세한 설명은 PEP 587 [https://peps.python.org/pep-0587/]을 참조하십시오.

(Contributed by Victor Stinner in bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763].)

PEP 590: 벡터콜: CPython을 위한 빠른 호출 프로토콜

벡터콜(Vectorcall) 프로토콜 is added to the Python/C API. It is meant to formalize existing optimizations which were already done for various classes. Any static type implementing a callable can use this protocol.

이것은 현재 잠정적(provisional)입니다. 목표는 파이썬 3.9에서 완전히 공개하는 것입니다.

자세한 설명은 PEP 590 [https://peps.python.org/pep-0590/]을 참조하십시오.

(Contributed by Jeroen Demeyer, Mark Shannon and Petr Viktorin in bpo-36974 [https://bugs.python.org/issue?@action=redirect&bpo=36974].)

아웃 오브 밴드 데이터 버퍼를 사용하는 피클 프로토콜 5

멀티 코어나 멀티 머신 프로세싱을 활용하기 위해 pickle을 사용해서 파이썬 프로세스 간에 큰 데이터를 전송할 때, 메모리 복사를 줄이고 데이터 종속적 압축과 같은 사용자 정의 기술을 적용하여 전송을 최적화하는 것이 중요합니다.

pickle 프로토콜 5는 통신 계층의 재량에 따라 PEP 3118 [https://peps.python.org/pep-3118/] 호환 데이터가 주 피클 스트림과 별도로 전송될 수 있는 아웃 오브 밴드 버퍼를 지원합니다.

자세한 설명은 PEP 574 [https://peps.python.org/pep-0574/]를 참조하십시오.

(Contributed by Antoine Pitrou in bpo-36785 [https://bugs.python.org/issue?@action=redirect&bpo=36785].)

기타 언어 변경

continue 문은 구현 문제로 인해 finally 절에서 사용할 수 없었습니다. 파이썬 3.8에서는 이 제한이 제거되었습니다. (Contributed by Serhiy Storchaka in bpo-32489 [https://bugs.python.org/issue?@action=redirect&bpo=32489].)

bool, int 및 fractions.Fraction 형에는 이제 float와 decimal.Decimal에서 발견되는 것과 유사한 as_integer_ratio() 메서드가 있습니다. 이 작은 API 확장을 통해 numerator, denominator = x.as_integer_ratio()라고 쓰고 여러 숫자 형에서 작동하도록 할 수 있습니다. (Contributed by Lisa Roach in bpo-33073 [https://bugs.python.org/issue?@action=redirect&bpo=33073] and Raymond Hettinger in bpo-37819 [https://bugs.python.org/issue?@action=redirect&bpo=37819].)

int, float 및 complex의 생성자는 이제 해당 메서드 __int__(), __float__() 또는 __complex__()를 사용할 수 없을 때, __index__() 특수 메서드가 있으면 사용할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-20092 [https://bugs.python.org/issue?@action=redirect&bpo=20092].)

Added support of \N{name} escapes in regular expressions:

>>> notice = 'Copyright © 2019'
>>> copyright_year_pattern = re.compile(r'\N{copyright sign}\s*(\d{4})')
>>> int(copyright_year_pattern.search(notice).group(1))
2019

(Contributed by Jonathan Eunice and Serhiy Storchaka in bpo-30688 [https://bugs.python.org/issue?@action=redirect&bpo=30688].)

이제 딕셔너리와 딕셔너리 뷰는 reversed()를 사용하여 삽입 순서의 역순으로 이터레이트 할 수 있습니다. (Contributed by Rémi Lapeyre in bpo-33462 [https://bugs.python.org/issue?@action=redirect&bpo=33462].)

함수 호출에서 키워드 이름에 허용된 문법이 더 제한되었습니다. 특히, f((keyword)=arg)는 더는 허용되지 않습니다. 키워드 인자 대입 항의 왼쪽에 이름 그대로 이상의 것을 허용하려는 의도는 결코 없었습니다. (Contributed by Benjamin Peterson in bpo-34641 [https://bugs.python.org/issue?@action=redirect&bpo=34641].)

yield와 return 문에서의 일반화된 이터러블 언 패킹은 더는 둘러싸는 괄호를 요구하지 않습니다. 이는 yield와 return 문법이 일반 대입 문법과 더 잘 일치하도록 만듭니다:

>>> def parse(family):
...     lastname, *members = family.split()
...     return lastname.upper(), *members
...
>>> parse('simpsons homer marge bart lisa maggie')
('SIMPSONS', 'homer', 'marge', 'bart', 'lisa', 'maggie')

(Contributed by David Cuthbert and Jordan Chapman in bpo-32117 [https://bugs.python.org/issue?@action=redirect&bpo=32117].)

[(10, 20) (30, 40)]와 같은 코드에서처럼 쉼표가 빠질 때, 컴파일러는 유용한 제안과 함께 SyntaxWarning을 표시합니다. 이것은 단지 첫 번째 튜플이 콜러블이 아니라고 알리는 TypeError를 개선한 것입니다. (Contributed by Serhiy Storchaka in bpo-15248 [https://bugs.python.org/issue?@action=redirect&bpo=15248].)

datetime.date나 datetime.datetime의 서브 클래스와 datetime.timedelta 객체 간의 산술 연산은 이제 베이스 클래스가 아닌 서브 클래스의 인스턴스를 반환합니다. 이는 astimezone()과 같은 datetime.timedelta 산술을 직접 또는 간접적으로 사용하는 연산의 반환형에도 영향을 줍니다. (Contributed by Paul Ganssle in bpo-32417 [https://bugs.python.org/issue?@action=redirect&bpo=32417].)

파이썬 인터프리터가 Ctrl-C(SIGINT)에 의해 인터럽트 되고 그로 인한 KeyboardInterrupt 예외가 잡히지 않으면, 파이썬 프로세스는 이제 Ctrl-C로 인해 죽었다는 것을 호출한 프로세스가 감지할 수 있도록 SIGINT 시그널을 통해서나 올바른 종료 코드를 통해 종료합니다. POSIX와 윈도우의 셸은 대화식 세션에서 스크립트를 올바르게 종료하기 위해 이를 사용합니다. (Contributed by Google via Gregory P. Smith in bpo-1054041 [https://bugs.python.org/issue?@action=redirect&bpo=1054041].)

일부 고급 프로그래밍 스타일은 기존 함수에 대한 types.CodeType 객체를 갱신할 필요가 있습니다. 코드 객체는 불변이므로, 기존 코드 객체에 기반하는 새 코드 객체를 만들어야 합니다. 19개의 매개 변수 때문에, 다소 지루했습니다. 이제, 새로운 replace() 메서드를 사용하면 몇 가지 변경된 매개 변수만으로 복제본을 만들 수 있습니다.

다음은 data 매개 변수가 키워드 인자로 사용되지 않도록 statistics.mean() 함수를 변경하는 예입니다:

>>> from statistics import mean
>>> mean(data=[10, 20, 90])
40
>>> mean.__code__ = mean.__code__.replace(co_posonlyargcount=1)
>>> mean(data=[10, 20, 90])
Traceback (most recent call last):
  ...
TypeError: mean() got some positional-only arguments passed as keyword arguments: 'data'

(Contributed by Victor Stinner in bpo-37032 [https://bugs.python.org/issue?@action=redirect&bpo=37032].)

정수의 경우, pow() 함수의 세 인자 형식은 이제 밑이 모듈러스와 서로소일 때 음수 지수를 허용합니다. 지수가 -1일 때 밑에 대한 모듈러 역수를 계산하고, 다른 음수 지수에 대해서는 그 역수의 적절한 거듭제곱을 계산합니다. 예를 들어, 모듈로 137에 대한 38의 모듈러 역수 [https://en.wikipedia.org/wiki/Modular_multiplicative_inverse]를 계산하려면, 다음과 같이 작성하십시오:

>>> pow(38, -1, 137)
119
>>> 119 * 38 % 137
1

모듈러 역수는 선형 디오판토스 방정식(linear Diophantine equations) [https://en.wikipedia.org/wiki/Diophantine_equation]의 해에서 나타납니다. 예를 들어, 4258𝑥 + 147𝑦 = 369에 대한 정수해를 찾으려면, 먼저 4258𝑥 ≡ 369 (mod 147)로 다시 쓴 다음 해를 구하십시오:

>>> x = 369 * pow(4258, -1, 147) % 147
>>> y = (4258 * x - 369) // -147
>>> 4258 * x + 147 * y
369

(Contributed by Mark Dickinson in bpo-36027 [https://bugs.python.org/issue?@action=redirect&bpo=36027].)

키가 먼저 계산되고 값이 두 번째로 계산되도록, 딕셔너리 컴프리헨션은 딕셔너리 리터럴과 동기화되었습니다:

>>> # Dict comprehension
>>> cast = {input('role? '): input('actor? ') for i in range(2)}
role? King Arthur
actor? Chapman
role? Black Knight
actor? Cleese

>>> # Dict literal
>>> cast = {input('role? '): input('actor? ')}
role? Sir Robin
actor? Eric Idle

키 표현식에서 대입된 변수를 값 표현식에서 사용할 수 있기 때문에, 보장된 실행 순서는 대입 표현식에 유용합니다:

>>> names = ['Martin von Löwis', 'Łukasz Langa', 'Walter Dörwald']
>>> {(n := normalize('NFC', name)).casefold() : n for name in names}
{'martin von löwis': 'Martin von Löwis',
 'łukasz langa': 'Łukasz Langa',
 'walter dörwald': 'Walter Dörwald'}

(Contributed by Jörn Heissler in bpo-35224 [https://bugs.python.org/issue?@action=redirect&bpo=35224].)

object.__reduce__() 메서드는 이제 2개에서 6개 요소 길이의 튜플을 반환할 수 있습니다. 이전에는 5가 한계였습니다. 새로운 선택적 여섯 번째 요소는 (obj, state) 서명을 갖는 콜러블입니다. 이를 통해 특정 객체의 상태 갱신 동작을 직접 제어할 수 있습니다. None이 아니면, 이 콜러블은 객체의 __setstate__() 메서드보다 우선합니다. (Contributed by Pierre Glaser and Olivier Grisel in bpo-35900 [https://bugs.python.org/issue?@action=redirect&bpo=35900].)

새 모듈

새로운 importlib.metadata 모듈은 제삼자 패키지에서 메타 데이터를 읽을 수 있도록 (잠정적으로) 지원합니다. 예를 들어, 설치된 패키지의 버전 번호, 진입점 목록 등을 추출 할 수 있습니다:

>>> # Note following example requires that the popular "requests"
>>> # package has been installed.
>>>
>>> from importlib.metadata import version, requires, files
>>> version('requests')
'2.22.0'
>>> list(requires('requests'))
['chardet (<3.1.0,>=3.0.2)']
>>> list(files('requests'))[:5]
[PackagePath('requests-2.22.0.dist-info/INSTALLER'),
 PackagePath('requests-2.22.0.dist-info/LICENSE'),
 PackagePath('requests-2.22.0.dist-info/METADATA'),
 PackagePath('requests-2.22.0.dist-info/RECORD'),
 PackagePath('requests-2.22.0.dist-info/WHEEL')]

(Contributed by Barry Warsaw and Jason R. Coombs in bpo-34632 [https://bugs.python.org/issue?@action=redirect&bpo=34632].)

개선된 모듈

ast

이제 AST 노드는 노드 끝의 정확한 위치를 제공하는 end_lineno와 end_col_offset 어트리뷰트를 가집니다. (이것은 lineno와 col_offset 어트리뷰트가 있는 노드에만 적용됩니다.)

새 함수 ast.get_source_segment()는 특정 AST 노드의 소스 코드를 반환합니다.

(Contributed by Ivan Levkivskyi in bpo-33416 [https://bugs.python.org/issue?@action=redirect&bpo=33416].)

ast.parse() 함수에는 몇 가지 새로운 플래그가 있습니다:

type_comments=True는 특정 AST 노드와 연관된 PEP 484 [https://peps.python.org/pep-0484/]와 PEP 526 [https://peps.python.org/pep-0526/] 형 주석의 텍스트를 반환하도록 합니다;

mode='func_type'은 PEP 484 [https://peps.python.org/pep-0484/] “서명 형 주석”(함수 정의 AST 노드에 대해 반환됩니다)을 구문 분석하는 데 사용될 수 있습니다;

feature_version=(3, N)은 이전 버전의 파이썬 3을 지정할 수 있게 합니다. 예를 들어, feature_version=(3, 4)는 async와 await를 예약어가 아닌 단어로 취급합니다.

(Contributed by Guido van Rossum in bpo-35766 [https://bugs.python.org/issue?@action=redirect&bpo=35766].)

asyncio

asyncio.run()은 임시 API를 졸업하고 안정 API가 되었습니다. 이 함수는 이벤트 루프를 자동으로 관리하면서 코루틴을 실행하고 결과를 반환하는 데 사용할 수 있습니다. 예를 들면:

import asyncio

async def main():
    await asyncio.sleep(0)
    return 42

asyncio.run(main())

이것은 대략 다음과 동등합니다:

import asyncio

async def main():
    await asyncio.sleep(0)
    return 42

loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
try:
    loop.run_until_complete(main())
finally:
    asyncio.set_event_loop(None)
    loop.close()

실제 구현은 훨씬 더 복잡합니다. 따라서, asyncio.run()은 asyncio 프로그램을 실행하는 데 선호되는 방법이어야 합니다.

(Contributed by Yury Selivanov in bpo-32314 [https://bugs.python.org/issue?@action=redirect&bpo=32314].)

python -m asyncio를 실행하면 네이티브 하게 비동기 REPL을 시작합니다. 이를 통해 최상위 await가 있는 코드를 빠르게 실험할 수 있습니다. 더는 호출할 때마다 새로운 이벤트 루프를 만드는 asyncio.run()을 직접 호출할 필요가 없습니다:

$ python -m asyncio
asyncio REPL 3.8.0
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
>>> import asyncio
>>> await asyncio.sleep(10, result='hello')
hello

(Contributed by Yury Selivanov in bpo-37028 [https://bugs.python.org/issue?@action=redirect&bpo=37028].)

asyncio.CancelledError 예외는 이제 Exception이 아닌 BaseException을 상속하고, 더는 concurrent.futures.CancelledError를 상속하지 않습니다. (Contributed by Yury Selivanov in bpo-32528 [https://bugs.python.org/issue?@action=redirect&bpo=32528].)

윈도우에서, 기본 이벤트 루프는 이제 ProactorEventLoop 입니다. (Contributed by Victor Stinner in bpo-34687 [https://bugs.python.org/issue?@action=redirect&bpo=34687].)

ProactorEventLoop는 이제 UDP도 지원합니다. (Contributed by Adam Meily and Andrew Svetlov in bpo-29883 [https://bugs.python.org/issue?@action=redirect&bpo=29883].)

이제 ProactorEventLoop가 KeyboardInterrupt(“CTRL+C”)에 의해 인터럽트 될 수 있습니다. (Contributed by Vladimir Matveev in bpo-23057 [https://bugs.python.org/issue?@action=redirect&bpo=23057].)

asyncio.Task 내에 래핑 된 코루틴을 얻기 위한 asyncio.Task.get_coro()를 추가했습니다. (Contributed by Alex Grönholm in bpo-36999 [https://bugs.python.org/issue?@action=redirect&bpo=36999].)

이제 name 키워드 인자를 asyncio.create_task()나 create_task() 이벤트 루프 메서드에 전달하거나, 태스크 객체의 set_name() 메서드를 호출하여 asyncio 태스크의 이름을 지정할 수 있습니다. 태스크 이름은 asyncio.Task의 repr() 출력에 표시되며 get_name() 메서드를 사용하여 조회할 수도 있습니다. (Contributed by Alex Grönholm in bpo-34270 [https://bugs.python.org/issue?@action=redirect&bpo=34270].)

asyncio.loop.create_connection()에 Happy Eyeballs [https://en.wikipedia.org/wiki/Happy_Eyeballs]에 대한 지원이 추가되었습니다. 동작을 지정하기 위해, 두 개의 매개변수가 추가되었습니다: happy_eyeballs_delay와 interleave. Happy Eyeballs 알고리즘은 IPv4와 IPv6을 지원하는 응용 프로그램에서 둘 모두를 사용하여 동시에 연결을 시도하여 응답성을 향상합니다. (Contributed by twisteroid ambassador in bpo-33530 [https://bugs.python.org/issue?@action=redirect&bpo=33530].)

builtins

내장 compile()이 ast.PyCF_ALLOW_TOP_LEVEL_AWAIT 플래그를 받아들이도록 개선되었습니다. 이 새 플래그가 전달되면, compile()은 일반적으로 유효하지 문법으로 간주하는 최상위 수준 await, async for 및 async with 구문을 허용합니다. 그러면 CO_COROUTINE 플래그로 표시된 비동기 코드 객체가 반환될 수 있습니다. (Contributed by Matthias Bussonnier in bpo-34616 [https://bugs.python.org/issue?@action=redirect&bpo=34616])

collections

이제 collections.namedtuple()의 _asdict() 메서드는 collections.OrderedDict 대신 dict를 반환합니다. 파이썬 3.7부터 일반 딕셔너리가 순서를 보장하기 때문에 이것이 가능합니다. OrderedDict의 추가 기능이 필요하면, 제안된 해결 방법은 원하는 형으로 결과를 캐스팅하는 것입니다: OrderedDict(nt._asdict()). (Contributed by Raymond Hettinger in bpo-35864 [https://bugs.python.org/issue?@action=redirect&bpo=35864].)

cProfile

cProfile.Profile 클래스는 이제 컨텍스트 관리자로 사용할 수 있습니다. 다음처럼 코드 블록을 프로파일 하십시오:

import cProfile

with cProfile.Profile() as profiler:
      # code to be profiled
      ...

(Contributed by Scott Sanderson in bpo-29235 [https://bugs.python.org/issue?@action=redirect&bpo=29235].)

csv

csv.DictReader는 이제 collections.OrderedDict 대신 dict의 인스턴스를 반환합니다. 이 도구는 이제 여전히 필드 순서를 유지하면서 더 빠르고 메모리를 덜 사용합니다. (Contributed by Michael Selik in bpo-34003 [https://bugs.python.org/issue?@action=redirect&bpo=34003].)

curses

하부 ncurses 라이브러리에 대한 구조화된 버전 정보를 담는 새로운 변수를 추가했습니다: ncurses_version. (Contributed by Serhiy Storchaka in bpo-31680 [https://bugs.python.org/issue?@action=redirect&bpo=31680].)

ctypes

윈도우에서, CDLL 및 서브 클래스는 이제 하부 LoadLibraryEx 호출에 대한 플래그를 지정하는 winmode 매개 변수를 받아들입니다. 기본 플래그는 DLL이 저장된 경로(전체나 부분 경로가 초기 DLL을 로드하는 데 사용되었다면)와 add_dll_directory()로 추가된 경로를 포함하여 신뢰할 수 있는 위치에서만 DLL 종속성을 로드하도록 설정됩니다. (Contributed by Steve Dower in bpo-36085 [https://bugs.python.org/issue?@action=redirect&bpo=36085].)

datetime

Added new alternate constructors datetime.date.fromisocalendar() and datetime.datetime.fromisocalendar(), which construct date and datetime objects respectively from ISO year, week number, and weekday; these are the inverse of each class’s isocalendar method. (Contributed by Paul Ganssle in bpo-36004 [https://bugs.python.org/issue?@action=redirect&bpo=36004].)

functools

이제 functools.lru_cache()는 데코레이터를 반환하는 함수가 아닌 직접적인 데코레이터로 사용할 수 있습니다. 그래서 이 두 가지가 모두 지원됩니다:

@lru_cache
def f(x):
    ...

@lru_cache(maxsize=256)
def f(x):
    ...

(Contributed by Raymond Hettinger in bpo-36772 [https://bugs.python.org/issue?@action=redirect&bpo=36772].)

인스턴스 수명 동안 캐시 된 계산된 속성을 위한 새로운 functools.cached_property() 데코레이터를 추가했습니다.

import functools
import statistics

class Dataset:
   def __init__(self, sequence_of_numbers):
      self.data = sequence_of_numbers

   @functools.cached_property
   def variance(self):
      return statistics.variance(self.data)

(Contributed by Carl Meyer in bpo-21145 [https://bugs.python.org/issue?@action=redirect&bpo=21145])

싱글 디스패치를 사용하여 메서드를 제네릭 함수로 변환하는 새로운 functools.singledispatchmethod() 데코레이터를 추가했습니다:

from functools import singledispatchmethod
from contextlib import suppress

class TaskManager:

    def __init__(self, tasks):
        self.tasks = list(tasks)

    @singledispatchmethod
    def discard(self, value):
        with suppress(ValueError):
            self.tasks.remove(value)

    @discard.register(list)
    def _(self, tasks):
        targets = set(tasks)
        self.tasks = [x for x in self.tasks if x not in targets]

(Contributed by Ethan Smith in bpo-32380 [https://bugs.python.org/issue?@action=redirect&bpo=32380])

gc

이제 get_objects()는 객체를 가져올 세대(generation)를 나타내는 선택적 generation 매개 변수를 받을 수 있습니다. (Contributed by Pablo Galindo in bpo-36016 [https://bugs.python.org/issue?@action=redirect&bpo=36016].)

gettext

pgettext()와 그 변형을 추가했습니다. (Contributed by Franz Glasner, Éric Araujo, and Cheryl Sabella in bpo-2504 [https://bugs.python.org/issue?@action=redirect&bpo=2504].)

gzip

재현성 있는 출력을 위해 gzip.compress()에 mtime 매개 변수를 추가했습니다. (Contributed by Guo Ci Teo in bpo-34898 [https://bugs.python.org/issue?@action=redirect&bpo=34898].)

특정 유형의 유효하지 않거나 손상된 gzip 파일의 경우 이제 OSError 대신 BadGzipFile 예외가 발생합니다. (Contributed by Filip Gruszczyński, Michele Orrù, and Zackery Spytz in bpo-6584 [https://bugs.python.org/issue?@action=redirect&bpo=6584].)

IDLE과 idlelib

N 줄(기본적으로 50)을 초과하는 출력은 버튼으로 축소됩니다. N은 설정 대화 상자의 General 페이지의 PyShell 섹션에서 변경할 수 있습니다. 그보다 작은, 하지만 아주 길 수도 있는, 줄은 출력을 마우스 오른쪽 버튼으로 클릭하면 압착할 수 있습니다. 압착된 출력은 버튼을 더블 클릭해서 제자리에서 확장하거나, 버튼을 마우스 오른쪽 단추로 클릭하여 클립 보드나 별도의 창으로 확장할 수 있습니다. (Contributed by Tal Einat in bpo-1529353 [https://bugs.python.org/issue?@action=redirect&bpo=1529353].)

사용자 정의 설정으로 모듈을 실행하기 위해 Run 메뉴에 “Run Customized”를 추가합니다. 입력한 모든 명령 줄 인자는 sys.argv에 추가됩니다. 또한 다음 사용자 정의 실행을 위해 상자에 다시 나타납니다. 일반적인 셸 메인 모듈 재시작을 억제할 수도 있습니다. (Contributed by Cheryl Sabella, Terry Jan Reedy, and others in bpo-5680 [https://bugs.python.org/issue?@action=redirect&bpo=5680] and bpo-37627 [https://bugs.python.org/issue?@action=redirect&bpo=37627].)

IDLE 편집기 창에 선택적인 줄 번호를 추가했습니다. 창은 구성 대화 상자의 General 탭에서 설정하지 않는 한 줄 번호 없이 열립니다. 기존 창의 줄 번호는 옵션 메뉴에서 표시되거나 숨겨집니다. (Contributed by Tal Einat and Saimadhav Heblikar in bpo-17535 [https://bugs.python.org/issue?@action=redirect&bpo=17535].)

OS 네이티브 인코딩은 이제 파이썬 문자열과 Tcl 객체 간 변환에 사용됩니다. 이를 통해 IDLE은 그림 이모티콘과 기타 BMP가 아닌 문자를 사용할 수 있습니다. 이러한 문자는 표시하거나 클립 보드에 복사하고 클립보드에서 붙여넣을 수 있습니다. 문자열을 Tcl에서 파이썬으로 변환했다가 되돌리는 것은 이제 실패하지 않습니다. (많은 사람이 8년 동안 이 작업을 했지만, 마침내 Serhiy Storchaka가 이 문제를 bpo-13153 [https://bugs.python.org/issue?@action=redirect&bpo=13153]에서 해결했습니다.)

3.8.1의 새로운 기능:

커서 깜박임을 토글하는 옵션을 추가합니다. (Contributed by Zackery Spytz in bpo-4603 [https://bugs.python.org/issue?@action=redirect&bpo=4603].)

이스케이프 키는 이제 IDLE 완성(completion) 창을 닫습니다. (Contributed by Johnny Najera in bpo-38944 [https://bugs.python.org/issue?@action=redirect&bpo=38944].)

위의 변경 사항은 3.7 유지 보수 릴리스로 역 이식되었습니다.

모듈 이름 완성 리스트에 키워드를 추가합니다. (Contributed by Terry J. Reedy in bpo-37765 [https://bugs.python.org/issue?@action=redirect&bpo=37765].)

inspect

inspect.getdoc() 함수는 이제 __slots__ 어트리뷰트가 값이 독스트링인 dict면 독스트링을 찾을 수 있습니다. 이것은 property(), classmethod() 및 staticmethod()에 대해 이미 가지고 있는 것과 유사한 문서화 옵션을 제공합니다:

class AudioClip:
    __slots__ = {'bit_rate': 'expressed in kilohertz to one decimal place',
                 'duration': 'in seconds, rounded up to an integer'}
    def __init__(self, bit_rate, duration):
        self.bit_rate = round(bit_rate / 1000.0, 1)
        self.duration = ceil(duration)

(Contributed by Raymond Hettinger in bpo-36326 [https://bugs.python.org/issue?@action=redirect&bpo=36326].)

io

In development mode (-X env) and in debug build, the io.IOBase finalizer now logs the exception if the close() method fails. The exception is ignored silently by default in release build. (Contributed by Victor Stinner in bpo-18748 [https://bugs.python.org/issue?@action=redirect&bpo=18748].)

itertools

itertools.accumulate() 함수는 초깃값을 지정하기 위한 옵션 initial 키워드 인자를 추가했습니다:

>>> from itertools import accumulate
>>> list(accumulate([10, 5, 30, 15], initial=1000))
[1000, 1010, 1015, 1045, 1060]

(Contributed by Lisa Roach in bpo-34659 [https://bugs.python.org/issue?@action=redirect&bpo=34659].)

json.tool

모든 입력 행을 별도의 JSON 객체로 구문 분석하는 --json-lines 옵션을 추가했습니다. (Contributed by Weipeng Hong in bpo-31553 [https://bugs.python.org/issue?@action=redirect&bpo=31553].)

logging

Added a force keyword argument to logging.basicConfig(). When set to true, any existing handlers attached to the root logger are removed and closed before carrying out the configuration specified by the other arguments.

이것은 오랜 문제를 해결합니다. 일단 로거나 basicConfig()가 호출되면, basicConfig()에 대한 후속 호출은 조용히 무시되었습니다. 이로 인해 대화식 프롬프트나 Jupyter 노트북을 사용하여 다양한 로깅 구성 옵션을 갱신, 실험 또는 가르치기가 어려웠습니다.

(Suggested by Raymond Hettinger, implemented by Donghee Na, and reviewed by Vinay Sajip in bpo-33897 [https://bugs.python.org/issue?@action=redirect&bpo=33897].)

math

두 점 사이의 유클리드 거리를 계산하기 위한 새로운 함수 math.dist()가 추가되었습니다. (Contributed by Raymond Hettinger in bpo-33089 [https://bugs.python.org/issue?@action=redirect&bpo=33089].)

다중 차원을 처리하도록 math.hypot() 함수를 확장했습니다. 이전에는, 2-D 케이스 만 지원했습니다. (Contributed by Raymond Hettinger in bpo-33089 [https://bugs.python.org/issue?@action=redirect&bpo=33089].)

‘start’ 값(기본값: 1)과 숫자의 이터러블의 곱을 반환하는 sum()의 대응 물인 새 함수 math.prod()를 추가했습니다:

>>> prior = 0.8
>>> likelihoods = [0.625, 0.84, 0.30]
>>> math.prod(likelihoods, start=prior)
0.126

(Contributed by Pablo Galindo in bpo-35606 [https://bugs.python.org/issue?@action=redirect&bpo=35606].)

새로운 조합 함수(combinatoric functions) math.perm()와 math.comb()가 추가되었습니다:

>>> math.perm(10, 3)    # Permutations of 10 things taken 3 at a time
720
>>> math.comb(10, 3)    # Combinations of 10 things taken 3 at a time
120

(Contributed by Yash Aggarwal, Keller Fuchs, Serhiy Storchaka, and Raymond Hettinger in bpo-37128 [https://bugs.python.org/issue?@action=redirect&bpo=37128], bpo-37178 [https://bugs.python.org/issue?@action=redirect&bpo=37178], and bpo-35431 [https://bugs.python.org/issue?@action=redirect&bpo=35431].)

정수 제곱근을 부동 소수점으로 변환하지 않고 정확하게 계산하기 위한 새로운 함수 math.isqrt()를 추가했습니다. 새 함수는 제한 없이 큰 정수를 지원합니다. floor(sqrt(n)) 보다 빠르지만 math.sqrt() 보다 느립니다:

>>> r = 650320427
>>> s = r ** 2
>>> isqrt(s - 1)         # correct
650320426
>>> floor(sqrt(s - 1))   # incorrect
650320427

(Contributed by Mark Dickinson in bpo-36887 [https://bugs.python.org/issue?@action=redirect&bpo=36887].)

함수 math.factorial()은 더는 int-류가 아닌 인자를 받아들이지 않습니다. (Contributed by Pablo Galindo in bpo-33083 [https://bugs.python.org/issue?@action=redirect&bpo=33083].)

mmap

mmap.mmap 클래스에는 이제 madvise() 시스템 호출에 액세스하는 madvise() 메서드가 있습니다. (Contributed by Zackery Spytz in bpo-32941 [https://bugs.python.org/issue?@action=redirect&bpo=32941].)

multiprocessing

새로운 multiprocessing.shared_memory 모듈을 추가했습니다. (Contributed by Davin Potts in bpo-35813 [https://bugs.python.org/issue?@action=redirect&bpo=35813].)

macOS에서, 이제 기본적으로 spawn 시작 방법이 사용됩니다. (Contributed by Victor Stinner in bpo-33725 [https://bugs.python.org/issue?@action=redirect&bpo=33725].)

os

확장 모듈을 임포트 하거나 ctypes를 사용하여 DLL을 로드할 때 네이티브 종속성에 대한 추가 검색 경로를 제공하기 위해 윈도우에서 새로운 함수 add_dll_directory()가 추가되었습니다. (Contributed by Steve Dower in bpo-36085 [https://bugs.python.org/issue?@action=redirect&bpo=36085].)

새로운 os.memfd_create() 함수가 추가되어 memfd_create() 시스템 호출을 감쌉니다. (Contributed by Zackery Spytz and Christian Heimes in bpo-26836 [https://bugs.python.org/issue?@action=redirect&bpo=26836].)

윈도우에서 재해석 지점(reparse points - 심볼릭 링크와 디렉터리 정션(directory junction)을 포함합니다)을 처리하기 위한 많은 수동 논리가 운영 체제로 위임되었습니다. 특히, os.stat()은 이제 운영 체제에서 지원하는 모든 것을 탐색하지만, os.lstat()은 “이름 서로게이트(name surrogates)”로 식별되는 재해석 지점만 열고 다른 이름은 os.stat()처럼 엽니다. 모든 경우에, stat_result.st_mode는 심볼릭 링크에만 S_IFLNK를 설정하고 다른 유형의 재해석 지점에는 설정하지 않습니다. 다른 유형의 재해석 지점을 식별하려면, 새 stat_result.st_reparse_tag 어트리뷰트를 확인하십시오.

윈도우에서, os.readlink()는 이제 디렉터리 정션을 읽을 수 있습니다. islink()는 디렉터리 정션에 대해 False를 반환함에 유의하십시오. 따라서 islink를 먼저 확인하는 코드는 정션을 계속 디렉터리로 처리하지만, os.readlink()의 에러를 처리하는 코드는 정션을 이제 링크로 처리할 수 있습니다.

(Contributed by Steve Dower in bpo-37834 [https://bugs.python.org/issue?@action=redirect&bpo=37834].)

os.path

exists(), lexists(), isdir(), isfile(), islink() 및 ismount()와 같은 불리언 결과를 반환하는 os.path 함수는 이제 OS 수준에서 표현할 수 없는 문자나 바이트를 포함하는 경로에 대해 ValueError나 그것의 서브 클래스 UnicodeEncodeError 와 UnicodeDecodeError 를 발생시키는 대신 False를 반환합니다. (Contributed by Serhiy Storchaka in bpo-33721 [https://bugs.python.org/issue?@action=redirect&bpo=33721].).

윈도우에서 expanduser()는 이제 USERPROFILE 환경 변수를 선호하며 일반적으로 일반 사용자 계정에 설정되지 않는 HOME을 사용하지 않습니다. (Contributed by Anthony Sottile in bpo-36264 [https://bugs.python.org/issue?@action=redirect&bpo=36264].)

윈도우에서 isdir()은 존재하지 않는 디렉터리에 대한 링크에 대해 더는 True를 반환하지 않습니다.

윈도우에서 realpath()는 이제 심볼릭 링크와 디렉터리 정션을 포함하는 재해석 지점을 결정(resolve)합니다.

(Contributed by Steve Dower in bpo-37834 [https://bugs.python.org/issue?@action=redirect&bpo=37834].)

pathlib

pathlib.Path methods that return a boolean result like exists(), is_dir(), is_file(), is_mount(), is_symlink(), is_block_device(), is_char_device(), is_fifo(), is_socket() now return False instead of raising ValueError or its subclass UnicodeEncodeError for paths that contain characters unrepresentable at the OS level. (Contributed by Serhiy Storchaka in bpo-33721 [https://bugs.python.org/issue?@action=redirect&bpo=33721].)

Added pathlib.Path.link_to() which creates a hard link pointing to a path. (Contributed by Joannah Nanjekye in bpo-26978 [https://bugs.python.org/issue?@action=redirect&bpo=26978]) Note that link_to was deprecated in 3.10 and removed in 3.12 in favor of a hardlink_to method added in 3.10 which matches the semantics of the existing symlink_to method.

pickle

C 최적화된 Pickler를 서브 클래싱하는 pickle 확장은 이제 특수 reducer_override() 메서드를 정의하여 함수와 클래스의 피클링 로직을 재정의할 수 있습니다. (Contributed by Pierre Glaser and Olivier Grisel in bpo-35900 [https://bugs.python.org/issue?@action=redirect&bpo=35900].)

plistlib

새로운 plistlib.UID가 추가되었으며 NSKeyedArchiver 인코딩된 바이너리 plist를 읽고 쓰는 지원을 활성화했습니다. (Contributed by Jon Janzen in bpo-26707 [https://bugs.python.org/issue?@action=redirect&bpo=26707].)

pprint

pprint 모듈은 여러 함수에 sort_dicts 매개 변수를 추가했습니다. 기본적으로, 이러한 함수는 렌더링이나 인쇄 전에 딕셔너리를 계속 정렬합니다. 그러나, sort_dicts가 거짓으로 설정되면, 딕셔너리는 키가 삽입된 순서를 유지합니다. 디버깅하는 동안 JSON 입력과 비교하는 데 유용 할 수 있습니다.

또한, pprint.pprint()와 유사하지만 sort_dicts가 False로 기본 설정된 새로운 편의 함수 pprint.pp()가 있습니다:

>>> from pprint import pprint, pp
>>> d = dict(source='input.txt', operation='filter', destination='output.txt')
>>> pp(d, width=40)                  # Original order
{'source': 'input.txt',
 'operation': 'filter',
 'destination': 'output.txt'}
>>> pprint(d, width=40)              # Keys sorted alphabetically
{'destination': 'output.txt',
 'operation': 'filter',
 'source': 'input.txt'}

(Contributed by Rémi Lapeyre in bpo-30670 [https://bugs.python.org/issue?@action=redirect&bpo=30670].)

py_compile

py_compile.compile()은 이제 조용한 모드를 지원합니다. (Contributed by Joannah Nanjekye in bpo-22640 [https://bugs.python.org/issue?@action=redirect&bpo=22640].)

shlex

새 shlex.join() 함수는 shlex.split()의 역함수로 작동합니다. (Contributed by Bo Bayles in bpo-32102 [https://bugs.python.org/issue?@action=redirect&bpo=32102].)

shutil

shutil.copytree()는 이제 새로운 dirs_exist_ok 키워드 인자를 받아들입니다. (Contributed by Josh Bronson in bpo-20849 [https://bugs.python.org/issue?@action=redirect&bpo=20849].)

shutil.make_archive()는 이제 이식성과 표준 적합성을 향상하기 위해 새로운 아카이브에 최신 pax (POSIX.1-2001) 형식을 기본으로 합니다, tarfile 모듈에 대한 해당 변경 사항을 상속했습니다. (Contributed by C.A.M. Gerlach in bpo-30661 [https://bugs.python.org/issue?@action=redirect&bpo=30661].)

윈도우에서 shutil.rmtree()는 이제 그 내용을 먼저 재귀적으로 삭제하지 않고 디렉터리 정션을 삭제합니다. (Contributed by Steve Dower in bpo-37834 [https://bugs.python.org/issue?@action=redirect&bpo=37834].)

socket

Added create_server() and has_dualstack_ipv6() convenience functions to automate the necessary tasks usually involved when creating a server socket, including accepting both IPv4 and IPv6 connections on the same socket. (Contributed by Giampaolo Rodolà in bpo-17561 [https://bugs.python.org/issue?@action=redirect&bpo=17561].)

The socket.if_nameindex(), socket.if_nametoindex(), and socket.if_indextoname() functions have been implemented on Windows. (Contributed by Zackery Spytz in bpo-37007 [https://bugs.python.org/issue?@action=redirect&bpo=37007].)

ssl

TLS 1.3 포스트 핸드 셰이크 인증을 활성화하는 post_handshake_auth와 시작하는 verify_client_post_handshake()를 추가했습니다. (Contributed by Christian Heimes in bpo-34670 [https://bugs.python.org/issue?@action=redirect&bpo=34670].)

statistics

Added statistics.fmean() as a faster, floating-point variant of statistics.mean(). (Contributed by Raymond Hettinger and Steven D’Aprano in bpo-35904 [https://bugs.python.org/issue?@action=redirect&bpo=35904].)

Added statistics.geometric_mean() (Contributed by Raymond Hettinger in bpo-27181 [https://bugs.python.org/issue?@action=redirect&bpo=27181].)

가장 빈번한 값의 리스트를 반환하는 statistics.multimode()가 추가되었습니다. (Contributed by Raymond Hettinger in bpo-35892 [https://bugs.python.org/issue?@action=redirect&bpo=35892].)

데이터나 분포를 등분위 간격(equiprobable intervals)(예를 들어, 4분위 수(quattiles), 십분위 수(deciles) 또는 백분위 수(percentiles))으로 나누는 statistics.quantiles()를 추가했습니다. (Contributed by Raymond Hettinger in bpo-36546 [https://bugs.python.org/issue?@action=redirect&bpo=36546].)

무작위 변수의 정규 분포를 만들고 조작하기 위한 도구인 statistics.NormalDist를 추가했습니다. (Contributed by Raymond Hettinger in bpo-36018 [https://bugs.python.org/issue?@action=redirect&bpo=36018].)

>>> temperature_feb = NormalDist.from_samples([4, 12, -3, 2, 7, 14])
>>> temperature_feb.mean
6.0
>>> temperature_feb.stdev
6.356099432828281

>>> temperature_feb.cdf(3)            # Chance of being under 3 degrees
0.3184678262814532
>>> # Relative chance of being 7 degrees versus 10 degrees
>>> temperature_feb.pdf(7) / temperature_feb.pdf(10)
1.2039930378537762

>>> el_niño = NormalDist(4, 2.5)
>>> temperature_feb += el_niño        # Add in a climate effect
>>> temperature_feb
NormalDist(mu=10.0, sigma=6.830080526611674)

>>> temperature_feb * (9/5) + 32      # Convert to Fahrenheit
NormalDist(mu=50.0, sigma=12.294144947901014)
>>> temperature_feb.samples(3)        # Generate random samples
[7.672102882379219, 12.000027119750287, 4.647488369766392]

sys

“발생시킬 수 없는 예외(unraisable exceptions)” 처리 방법을 제어하기 위해 재정의할 수 있는 새로운 sys.unraisablehook() 함수를 추가했습니다. 예외가 발생했지만, 파이썬에서 처리할 방법이 없을 때 호출됩니다. 예를 들어, 파괴자(destructor)가 예외를 발생시키거나 가비지 수집(gc.collect()) 중에. (Contributed by Victor Stinner in bpo-36829 [https://bugs.python.org/issue?@action=redirect&bpo=36829].)

tarfile

tarfile 모듈은 새로운 아카이브를 만들 때 이제 이전의 GNU 전용이 아닌 최신 pax (POSIX.1-2001) 형식을 기본값으로 사용합니다. 이것은 표준화되고 확장 가능한 형식으로 일관된 인코딩(UTF-8)을 사용하여 플랫폼 간 이식성을 개선하고, 몇 가지 다른 이점을 제공합니다. (Contributed by C.A.M. Gerlach in bpo-36268 [https://bugs.python.org/issue?@action=redirect&bpo=36268].)

threading

잡히지 않은 threading.Thread.run() 예외를 처리하는 새로운 threading.excepthook() 함수를 추가했습니다. 잡히지 않은 threading.Thread.run() 예외가 처리되는 방식을 제어하기 위해 재정의될 수 있습니다. (Contributed by Victor Stinner in bpo-1230540 [https://bugs.python.org/issue?@action=redirect&bpo=1230540].)

새로운 threading.get_native_id() 함수와 native_id 어트리뷰트를 threading.Thread 클래스에 추가합니다. 이것들은 커널이 할당한 현재 스레드의 네이티브 정수 스레드 ID를 반환합니다. 이 기능은 특정 플랫폼에서만 사용할 수 있습니다, 자세한 내용은 get_native_id를 참조하십시오. (Contributed by Jake Tesler in bpo-36084 [https://bugs.python.org/issue?@action=redirect&bpo=36084].)

tokenize

tokenize 모듈은 이제 후행 줄 넘김이 없는 입력을 제공할 때 묵시적으로 NEWLINE 토큰을 출력합니다. 이 동작은 이제 C 토크나이저가 내부적으로 수행하는 것과 일치합니다. (Contributed by Ammar Askar in bpo-33899 [https://bugs.python.org/issue?@action=redirect&bpo=33899].)

tkinter

tkinter.Spinbox 클래스에 selection_from(), selection_present(), selection_range() 및 selection_to() 메서드를 추가했습니다. (Contributed by Juliette Monsel in bpo-34829 [https://bugs.python.org/issue?@action=redirect&bpo=34829].)

tkinter.Canvas 클래스에 moveto() 메서드를 추가했습니다. (Contributed by Juliette Monsel in bpo-23831 [https://bugs.python.org/issue?@action=redirect&bpo=23831].)

tkinter.PhotoImage 클래스는 이제 transparency_get()과 transparency_set() 메서드를 갖습니다. (Contributed by Zackery Spytz in bpo-25451 [https://bugs.python.org/issue?@action=redirect&bpo=25451].)

time

Added new clock CLOCK_UPTIME_RAW for macOS 10.12. (Contributed by Joannah Nanjekye in bpo-35702 [https://bugs.python.org/issue?@action=redirect&bpo=35702].)

typing

typing 모듈은 몇 가지 새로운 기능을 통합했습니다:

키별 형이 있는 딕셔너리 형. PEP 589 [https://peps.python.org/pep-0589/]와 typing.TypedDict를 참조하십시오. TypedDict는 문자열 키만 사용합니다. 기본적으로, 모든 키가 있어야 합니다. 키를 선택적으로 만들려면 “total=False”를 지정하십시오:

class Location(TypedDict, total=False):
    lat_long: tuple
    grid_square: str
    xy_coordinate: tuple

리터럴 형. PEP 586 [https://peps.python.org/pep-0586/]과 typing.Literal을 참조하십시오. Literal 형은 매개 변수나 반환 값이 하나 이상의 특정 리터럴 값으로 제한됨을 나타냅니다:

def get_status(port: int) -> Literal['connected', 'disconnected']:
    ...

“최종(final)” 변수, 함수, 메서드 및 클래스. PEP 591 [https://peps.python.org/pep-0591/], typing.Final 및 typing.final()을 참조하십시오. final 한정자는 정적 형 검사기에 서브 클래싱, 재정의 또는 재대입을 제한하도록 지시합니다:

pi: Final[float] = 3.1415926536

프로토콜 정의. PEP 544 [https://peps.python.org/pep-0544/], typing.Protocol 및 typing.runtime_checkable()을 참조하십시오. typing.SupportsInt와 같은 간단한 ABC는 이제 Protocol 서브 클래스입니다.

새 프로토콜 클래스 typing.SupportsIndex.

새 함수 typing.get_origin()과 typing.get_args().

unicodedata

The unicodedata module has been upgraded to use the Unicode 12.1.0 [https://blog.unicode.org/2019/05/unicode-12-1-en.html] release.

새 함수 is_normalized()를 문자열이 특정 정규화 형식인지 확인하는 데 사용할 수 있습니다. 종종 실제로 문자열을 정규화하는 것보다 훨씬 빠릅니다. (Contributed by Max Belanger, David Euresti, and Greg Price in bpo-32285 [https://bugs.python.org/issue?@action=redirect&bpo=32285] and bpo-37966 [https://bugs.python.org/issue?@action=redirect&bpo=37966]).

unittest

Mock의 비동기 버전을 지원하는 AsyncMock이 추가되었습니다. 테스트를 위해 적절한 새로운 assert 함수들이 추가되었습니다. (Contributed by Lisa Roach in bpo-26467 [https://bugs.python.org/issue?@action=redirect&bpo=26467]).

Added addModuleCleanup() and addClassCleanup() to unittest to support cleanups for setUpModule() and setUpClass(). (Contributed by Lisa Roach in bpo-24412 [https://bugs.python.org/issue?@action=redirect&bpo=24412].)

여러 mock assert 함수는 이제 실패 시 실제 호출의 리스트도 인쇄합니다. (Contributed by Petter Strandmark in bpo-35047 [https://bugs.python.org/issue?@action=redirect&bpo=35047].)

unittest 모듈은 unittest.IsolatedAsyncioTestCase를 통해 코루틴을 테스트 케이스로 사용하는 지원을 얻었습니다. (Contributed by Andrew Svetlov in bpo-32972 [https://bugs.python.org/issue?@action=redirect&bpo=32972].)

예:

import unittest

class TestRequest(unittest.IsolatedAsyncioTestCase):

    async def asyncSetUp(self):
        self.connection = await AsyncConnection()

    async def test_get(self):
        response = await self.connection.get("https://example.com")
        self.assertEqual(response.status_code, 200)

    async def asyncTearDown(self):
        await self.connection.close()

if __name__ == "__main__":
    unittest.main()

venv

venv는 이제 PowerShell Core 6.1에서 가상 환경을 활성화하기 위한 모든 플랫폼에 Activate.ps1 스크립트를 포함합니다. (Contributed by Brett Cannon in bpo-32718 [https://bugs.python.org/issue?@action=redirect&bpo=32718].)

weakref

weakref.proxy()에 의해 반환된 프락시 객체는 이제 다른 숫자 연산자에 더해 행렬 곱셈 연산자 @와 @=을 지원합니다. (Contributed by Mark Dickinson in bpo-36669 [https://bugs.python.org/issue?@action=redirect&bpo=36669].)

xml

DTD 및 외부 엔티티 조회에 대한 완화로서, xml.dom.minidom과 xml.sax 모듈은 기본적으로 더는 외부 엔티티를 처리하지 않습니다. (Contributed by Christian Heimes in bpo-17239 [https://bugs.python.org/issue?@action=redirect&bpo=17239].)

xml.etree.ElementTree 모듈의 .find*() 메서드는 이름 공간을 무시하는 {*}tag와 지정된 이름 공간의 모든 태그를 반환하는 {namespace}*와 같은 와일드카드 검색을 지원합니다. (Contributed by Stefan Behnel in bpo-28238 [https://bugs.python.org/issue?@action=redirect&bpo=28238].)

The xml.etree.ElementTree module provides a new function –xml.etree.ElementTree.canonicalize() that implements C14N 2.0. (Contributed by Stefan Behnel in bpo-13611 [https://bugs.python.org/issue?@action=redirect&bpo=13611].)

xml.etree.ElementTree.XMLParser의 대상 객체는 새 콜백 메서드 start_ns()와 end_ns()를 통해 이름 공간 선언 이벤트를 수신할 수 있습니다. 또한, xml.etree.ElementTree.TreeBuilder 대상은 주석과 처리 명령어에 대한 이벤트를 처리하여 생성된 트리에 포함하도록 구성할 수 있습니다. (Contributed by Stefan Behnel in bpo-36676 [https://bugs.python.org/issue?@action=redirect&bpo=36676] and bpo-36673 [https://bugs.python.org/issue?@action=redirect&bpo=36673].)

xmlrpc

xmlrpc.client.ServerProxy는 이제 각 요청과 함께 보낼 HTTP 헤더의 시퀀스를 위한 선택적 headers 키워드 인자를 지원합니다. 무엇보다도, 기본 베이식 인증(basic authentication)에서 더 빠른 세션 인증(session authentication)으로 업그레이드 할 수 있도록 합니다. (Contributed by Cédric Krier in bpo-35153 [https://bugs.python.org/issue?@action=redirect&bpo=35153].)

최적화

subprocess 모듈은 이제 성능 향상을 위해 몇몇 경우 os.posix_spawn() 함수를 사용할 수 있습니다. 현재, 다음과 같은 조건이 모두 충족될 때 macOS와 리눅스(glibc 2.24 이상 사용)에서만 사용됩니다:

close_fds가 거짓입니다.

preexec_fn, pass_fds, cwd 및 start_new_session 매개 변수가 설정되지 않았습니다.

executable 경로가 디렉터리를 포함합니다.

(Contributed by Joannah Nanjekye and Victor Stinner in bpo-35537 [https://bugs.python.org/issue?@action=redirect&bpo=35537].)

shutil.copyfile(), shutil.copy(), shutil.copy2(), shutil.copytree() 및 shutil.move()는 파일을 보다 효율적으로 복사하기 위해 리눅스와 macOS에서 플랫폼별 “빠른 복사(fast-copy)” 시스템 호출을 사용합니다. “빠른 복사”는 복사 작업이 커널 내에서 발생하여 “outfd.write(infd.read())”처럼 파이썬에서 사용자 공간(userspace) 버퍼를 사용하지 않도록 합니다. 윈도우에서 shutil.copyfile()은 더 큰 기본 버퍼 크기(16 KiB 대신 1 MiB)를 사용하고 shutil.copyfileobj()의 memoryview() 기반 변형이 사용됩니다. 같은 파티션 내에서 512 MiB 파일을 복사할 때 속도 개선은 리눅스에서는 약 +26%, macOS에서는 +50%, 윈도우에서는 +40%입니다. 또한, 훨씬 적은 CPU 사이클이 소모됩니다. 플랫폼 의존적 효율적인 복사 연산 절을 참조하십시오. (Contributed by Giampaolo Rodolà in bpo-33671 [https://bugs.python.org/issue?@action=redirect&bpo=33671].)

shutil.copytree()는 os.scandir() 함수를 사용하고 이것에 의존하는 모든 복사 함수는 캐시 된 os.stat() 값을 사용합니다. 8000개의 파일이 있는 디렉터리를 복사할 때 속도 개선은 리눅스에서는 +9%, 윈도우에서는 +20%, 윈도우 SMB 공유에서는 +30%입니다. 또한, os.stat() 시스템 호출 수가 38% 감소하여 특히 shutil.copytree()가 네트워크 파일 시스템에서 더 빠릅니다. (Contributed by Giampaolo Rodolà in bpo-33695 [https://bugs.python.org/issue?@action=redirect&bpo=33695].)

pickle 모듈의 기본 프로토콜은 이제 파이썬 3.4에서 처음 소개된 프로토콜 4입니다. 파이썬 3.0부터 사용 가능한 프로토콜 3보다 성능이 우수하고 크기가 작습니다.

Removed one Py_ssize_t member from PyGC_Head. All GC tracked objects (e.g. tuple, list, dict) size is reduced 4 or 8 bytes. (Contributed by Inada Naoki in bpo-33597 [https://bugs.python.org/issue?@action=redirect&bpo=33597].)

uuid.UUID는 이제 __slots__를 사용하여 메모리 사용량을 줄입니다. (Contributed by Wouter Bolsterlee and Tal Einat in bpo-30977 [https://bugs.python.org/issue?@action=redirect&bpo=30977])

operator.itemgetter()의 33% 성능 향상. 인자 처리를 최적화하고 튜플에 대한 하나의 음수가 아닌 정수 인덱스의 흔한 경우에 대한 빠른 경로를 추가했습니다 (표준 라이브러리의 일반적인 사용 사례입니다). (Contributed by Raymond Hettinger in bpo-35664 [https://bugs.python.org/issue?@action=redirect&bpo=35664].)

collections.namedtuple()에서의 필드 조회 속도 향상. 이제 두 배 이상 빨라져, 파이썬에서 가장 빠른 인스턴스 변수 조회 형식이 되었습니다. (Contributed by Raymond Hettinger, Pablo Galindo, and Joe Jevnik, Serhiy Storchaka in bpo-32492 [https://bugs.python.org/issue?@action=redirect&bpo=32492].)

list 생성자는 입력 이터러블의 길이를 알 수 있으면 (입력이 __len__을 구현하면) 내부 항목 버퍼를 초과 할당하지 않습니다. 이것은 생성된 리스트가 평균 12% 작게 만듭니다. (Contributed by Raymond Hettinger and Pablo Galindo in bpo-33234 [https://bugs.python.org/issue?@action=redirect&bpo=33234].)

클래스 변수 쓰기 속도 두 배 향상. 특수하지 않은(non-dunder) 어트리뷰트가 갱신되었을 때, 슬롯 갱신을 위한 불필요한 호출이 있었습니다. (Contributed by Stefan Behnel, Pablo Galindo Salgado, Raymond Hettinger, Neil Schemenauer, and Serhiy Storchaka in bpo-36012 [https://bugs.python.org/issue?@action=redirect&bpo=36012].)

많은 내장 함수와 메서드에 전달된 인자를 변환하는 오버헤드 감소. 이것은 몇몇 간단한 내장 함수와 메서드 호출을 20–50%까지 가속합니다. (Contributed by Serhiy Storchaka in bpo-23867 [https://bugs.python.org/issue?@action=redirect&bpo=23867], bpo-35582 [https://bugs.python.org/issue?@action=redirect&bpo=35582] and bpo-36127 [https://bugs.python.org/issue?@action=redirect&bpo=36127].)

LOAD_GLOBAL 명령어는 이제 새로운 “옵코드(opcode) 단위 캐시” 메커니즘을 사용합니다. 이제 약 40% 빨라졌습니다. (Contributed by Yury Selivanov and Inada Naoki in bpo-26219 [https://bugs.python.org/issue?@action=redirect&bpo=26219].)

빌드와 C API 변경

기본 sys.abiflags는 빈 문자열이 되었습니다: pymalloc을 위한 m 플래그가 쓸모없게 되었으므로 (pymalloc을 포함하거나 포함하지 않는 빌드는 ABI 호환입니다) 제거되었습니다. (Contributed by Victor Stinner in bpo-36707 [https://bugs.python.org/issue?@action=redirect&bpo=36707].)

변경의 예:

python3.8 프로그램만 설치되고, python3.8m 프로그램은 사라졌습니다.

python3.8-config 스크립트만 설치되고, python3.8m-config 스크립트는 사라졌습니다.

m 플래그는 동적 라이브러리 파일명의 접미사에서 제거되었습니다: 표준 라이브러리는 물론 PyPI에서 다운로드 한 것과 같은 제삼자 패키지에서 생성되고 설치된 확장 모듈. 예를 들어, 리눅스에서 파이썬 3.7 접미사 .cpython-37m-x86_64-linux-gnu.so는 파이썬 3.8에서 .cpython-38-x86_64-linux-gnu.so가 되었습니다.

여러 종류의 API를 더 잘 구분할 수 있도록 헤더 파일이 재구성되었습니다:

Include/*.h는 이식성 있는 공용 안정 C API 여야 합니다.

Include/cpython/*.h는 CPython에 고유한 불안정한 C API 여야 합니다; _Py나 _PY로 시작하는 일부 비공개 API가 포함된 공개 API.

Include/internal/*.h는 아주 CPython에 특정한 비공개 내부 C API입니다. 이 API는 과거 호환성 보증이 없어서, CPython 외부에서 사용해서는 안 됩니다. 이것은 함수를 호출하지 않고 CPython 내부에 액세스해야 하는 디버거나 프로파일과 같이 매우 구체적인 요구 사항을 위해서만 노출됩니다. 이 API는 이제 make install에 의해 설치됩니다.

(Contributed by Victor Stinner in bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134] and bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081], Eric Snow가 파이썬 3.7에서 시작한 작업.)

일부 매크로는 정적 인라인 함수로 변환되었습니다: 매개 변수 형과 반환형이 잘 정의되며, 매크로에 특정한 문제가 없으며, 변수는 지역 스코프를 갖습니다. 예:

Py_INCREF(), Py_DECREF()

Py_XINCREF(), Py_XDECREF()

PyObject_INIT(), PyObject_INIT_VAR()

Private functions: _PyObject_GC_TRACK(), _PyObject_GC_UNTRACK(), _Py_Dealloc()

(Contributed by Victor Stinner in bpo-35059 [https://bugs.python.org/issue?@action=redirect&bpo=35059].)

The PyByteArray_Init() and PyByteArray_Fini() functions have been removed. They did nothing since Python 2.7.4 and Python 3.2.0, were excluded from the limited API (stable ABI), and were not documented. (Contributed by Victor Stinner in bpo-35713 [https://bugs.python.org/issue?@action=redirect&bpo=35713].)

PyExceptionClass_Name()의 결과는 이제 char * 대신 const char * 형입니다. (Contributed by Serhiy Storchaka in bpo-33818 [https://bugs.python.org/issue?@action=redirect&bpo=33818].)

Modules/Setup.dist와 Modules/Setup의 이중성이 제거되었습니다. 이전에는, CPython 소스 트리를 갱신할 때, 업스트림 변경 사항을 반영하기 위해 Modules/Setup.dist(소스 트리 내부)를 Modules/Setup(빌드 트리 내부)으로 수동으로 복사해야 했습니다. 이는 패키지 작성자에게는 작은 이점을 제공했지만, 파일 복사를 잊어버리면 빌드가 실패할 수 있어서 CPython 개발자들을 자주 귀찮게 만들었습니다.

이제 빌드 시스템은 항상 소스 트리 안의 Modules/Setup에서 읽습니다. 그 파일을 사용자 정의하고 싶은 사람들은 소스 트리에 대한 다른 변경과 마찬가지로 CPython의 git 포크나 패치 파일로 변경 사항을 유지하는 것이 좋습니다.

(Contributed by Antoine Pitrou in bpo-32430 [https://bugs.python.org/issue?@action=redirect&bpo=32430].)

PyLong_AsLong()과 같은 파이썬 숫자를 C 정수로 변환하는 함수와, PyArg_ParseTuple()처럼 'i'와 같은 정수 변환 포맷 단위로 인자를 구문 분석하는 함수는, 이제 사용할 수 있다면 __int__() 대신 __index__() 특수 메서드를 사용합니다. __int__() 메서드가 있지만 __index__() 메서드가 없는 객체(Decimal과 Fraction 같은)에 대해서 폐지 경고가 발생합니다. PyNumber_Check()는 이제 __index__()를 구현하는 객체에 대해 1을 반환합니다. PyNumber_Long(), PyNumber_Float() 및 PyFloat_AsDouble()은 이제 사용할 수 있으면 __index__() 메서드를 사용합니다. (Contributed by Serhiy Storchaka in bpo-36048 [https://bugs.python.org/issue?@action=redirect&bpo=36048] and bpo-20092 [https://bugs.python.org/issue?@action=redirect&bpo=20092].)

힙에 할당된 형 객체는 이제 PyType_GenericAlloc()이 아닌 PyObject_Init()(그리고 이것과 평행한 매크로 PyObject_INIT)에서 참조 횟수를 증가시킵니다. 인스턴스 할당이나 할당 해제를 수정하는 형은 조정이 필요할 수 있습니다. (Contributed by Eddie Elizondo in bpo-35810 [https://bugs.python.org/issue?@action=redirect&bpo=35810].)

The new function PyCode_NewWithPosOnlyArgs() allows to create code objects like PyCode_New(), but with an extra posonlyargcount parameter for indicating the number of positional-only arguments. (Contributed by Pablo Galindo in bpo-37221 [https://bugs.python.org/issue?@action=redirect&bpo=37221].)

Py_SetPath() now sets sys.executable to the program full path (Py_GetProgramFullPath()) rather than to the program name (Py_GetProgramName()). (Contributed by Victor Stinner in bpo-38234 [https://bugs.python.org/issue?@action=redirect&bpo=38234].)

폐지

distutils bdist_wininst 명령은 이제 폐지되었습니다, 대신 bdist_wheel(wheel 패키지)을 사용하십시오. (Contributed by Victor Stinner in bpo-37481 [https://bugs.python.org/issue?@action=redirect&bpo=37481].)

ElementTree 모듈의 폐지된 메서드 getchildren()과 getiterator()는 이제 PendingDeprecationWarning 대신 DeprecationWarning을 발생시킵니다. 이것들은 파이썬 3.9에서 제거될 것입니다. (Contributed by Serhiy Storchaka in bpo-29209 [https://bugs.python.org/issue?@action=redirect&bpo=29209].)

concurrent.futures.ThreadPoolExecutor의 인스턴스가 아닌 객체를 loop.set_default_executor()로 전달하는 것은 폐지되었고 파이썬 3.9에서 금지될 것입니다. (Contributed by Elvis Pranskevichus in bpo-34075 [https://bugs.python.org/issue?@action=redirect&bpo=34075].)

The __getitem__() methods of xml.dom.pulldom.DOMEventStream, wsgiref.util.FileWrapper and fileinput.FileInput have been deprecated.

이 메서드의 구현은 index 매개 변수를 무시하고 대신 다음 항목을 반환했습니다. (Contributed by Berker Peksag in bpo-9372 [https://bugs.python.org/issue?@action=redirect&bpo=9372].)

typing.NamedTuple 클래스는 _field_types 어트리뷰트를 폐지했고, 같은 정보를 갖는 __annotations__ 어트리뷰트로 대신합니다. (Contributed by Raymond Hettinger in bpo-36320 [https://bugs.python.org/issue?@action=redirect&bpo=36320].)

ast 클래스 Num, Str, Bytes, NameConstant 및 Ellipsis는 폐지된 것으로 간주하고 향후 파이썬 버전에서 제거될 예정입니다. 대신 Constant를 사용해야 합니다. (Contributed by Serhiy Storchaka in bpo-32892 [https://bugs.python.org/issue?@action=redirect&bpo=32892].)

ast.NodeVisitor 메서드 visit_Num(), visit_Str(), visit_Bytes(), visit_NameConstant() 및 visit_Ellipsis()는 이제 폐지되었으며 향후 파이썬 버전에서는 호출되지 않을 것입니다. 모든 상수 노드를 처리하기 위해서는 visit_Constant() 메서드를 추가하십시오. (Contributed by Serhiy Storchaka in bpo-36917 [https://bugs.python.org/issue?@action=redirect&bpo=36917].)

asyncio.coroutine() 데코레이터는 폐지되었고 버전 3.10에서 제거됩니다. @asyncio.coroutine 대신, async def를 사용하십시오. (Contributed by Andrew Svetlov in bpo-36921 [https://bugs.python.org/issue?@action=redirect&bpo=36921].)

asyncio에서, 다음에 대해 loop 인자의 명시적 전달은 폐지되었고 버전 3.10에서 제거됩니다: asyncio.sleep(), asyncio.gather(), asyncio.shield(), asyncio.wait_for(), asyncio.wait(), asyncio.as_completed(), asyncio.Task, asyncio.Lock, asyncio.Event, asyncio.Condition, asyncio.Semaphore, asyncio.BoundedSemaphore, asyncio.Queue, asyncio.create_subprocess_exec() 및 asyncio.create_subprocess_shell().

코루틴 객체를 asyncio.wait()에 명시적으로 전달하는 것은 폐지되었고 버전 3.11에서 제거됩니다. (Contributed by Yury Selivanov in bpo-34790 [https://bugs.python.org/issue?@action=redirect&bpo=34790].)

gettext 모듈에서는 다음 함수와 메서드가 폐지되었습니다: lgettext(), ldgettext(), lngettext() 및 ldngettext(). 이들은 인코딩된 바이트열을 반환하며, 번역된 문자열에 인코딩 문제가 있을 때 예기치 않은 유니코드 관련 예외가 발생할 수 있습니다. 파이썬 3에서 유니코드 문자열을 반환하는 대안을 사용하는 것이 훨씬 낫습니다. 이 함수들은 오랫동안 망가져 있었습니다.

함수 bind_textdomain_codeset(), 메서드 output_charset()과 set_output_charset(), 함수 translation()과 install()의 codeset 매개 변수도 폐지되었습니다, l*gettext() 함수에서만 사용되기 때문입니다. (Contributed by Serhiy Storchaka in bpo-33710 [https://bugs.python.org/issue?@action=redirect&bpo=33710].)

The isAlive() method of threading.Thread has been deprecated. (Contributed by Donghee Na in bpo-35283 [https://bugs.python.org/issue?@action=redirect&bpo=35283].)

정수 인자를 받아들이는 많은 내장과 확장 함수는 이제 Decimal들, Fraction들 및 정수로 변환될 때 손실을 수반하는 다른 객체들(예를 들어, __int__() 메서드는 있지만 __index__() 메서드는 없는 것들)에 대해 폐지 경고를 발생시킵니다. 이후 버전에서는 에러가 될 것입니다. (Contributed by Serhiy Storchaka in bpo-36048 [https://bugs.python.org/issue?@action=redirect&bpo=36048].)

다음 인자들을 키워드 인자로 전달하는 것이 폐지되었습니다:

functools.partialmethod(), weakref.finalize(), profile.Profile.runcall(), cProfile.Profile.runcall(), bdb.Bdb.runcall(), trace.Trace.runfunc() 및 curses.wrapper()의 func.

unittest.TestCase.addCleanup()의 function.

concurrent.futures.ThreadPoolExecutor과 concurrent.futures.ProcessPoolExecutor의 submit() 메서드의 fn.

contextlib.ExitStack.callback(), contextlib.AsyncExitStack.callback() 및 contextlib.AsyncExitStack.push_async_callback()의 callback

multiprocessing.managers.Server와 multiprocessing.managers.SharedMemoryServer의 create() 메서드의 c와 typeid.

weakref.finalize()의 obj.

파이썬의 향후 배포에서, 이것들은 위치 전용이 될 것입니다. (Contributed by Serhiy Storchaka in bpo-36492 [https://bugs.python.org/issue?@action=redirect&bpo=36492].)

API 및 기능 제거

다음 기능과 API는 파이썬 3.8에서 제거되었습니다.:

Starting with Python 3.3, importing ABCs from collections was deprecated, and importing should be done from collections.abc. Being able to import from collections was marked for removal in 3.8, but has been delayed to 3.9. (See gh-81134 [https://github.com/python/cpython/issues/81134].)

파이썬 3.7에서 폐지된, macpath 모듈이 제거되었습니다. (Contributed by Victor Stinner in bpo-35471 [https://bugs.python.org/issue?@action=redirect&bpo=35471].)

파이썬 3.3부터 폐지된 이후로, platform.popen() 함수는 제거되었습니다: 대신 os.popen()을 사용하십시오. (Contributed by Victor Stinner in bpo-35345 [https://bugs.python.org/issue?@action=redirect&bpo=35345].)

파이썬 3.3부터 폐지된 이후로, time.clock() 함수는 제거되었습니다: 잘 정의된 동작을 위해, 요구 사항에 따라 time.perf_counter()나 time.process_time()을 대신 사용하십시오. (Contributed by Matthias Bussonnier in bpo-36895 [https://bugs.python.org/issue?@action=redirect&bpo=36895].)

pyvenv 스크립트를 제거하고 python3.8 -m venv로 대체하여, 어떤 파이썬 인터프리터가 pyvenv 스크립트와 연결되어 있는지에 대한 혼란을 없애줍니다. (Contributed by Brett Cannon in bpo-25427 [https://bugs.python.org/issue?@action=redirect&bpo=25427].)

parse_qs, parse_qsl, and escape are removed from the cgi module. They are deprecated in Python 3.2 or older. They should be imported from the urllib.parse and html modules instead.

filemode 함수가 tarfile 모듈에서 제거되었습니다. 문서로 만들어지지 않았고, 파이썬 3.3부터 폐지되었습니다.

XMLParser 생성자는 더는 html 인자를 받아들이지 않습니다. 효과가 있었던 적이 없고 3.4에서 폐지되었습니다. 다른 모든 매개 변수는 이제 키워드 전용입니다. (Contributed by Serhiy Storchaka in bpo-29209 [https://bugs.python.org/issue?@action=redirect&bpo=29209].)

XMLParser의 doctype() 메서드를 제거했습니다. (Contributed by Serhiy Storchaka in bpo-29209 [https://bugs.python.org/issue?@action=redirect&bpo=29209].)

“unicode_internal” 코덱이 제거되었습니다. (Contributed by Inada Naoki in bpo-36297 [https://bugs.python.org/issue?@action=redirect&bpo=36297].)

sqlite3 모듈의 Cache와 Statement 객체는 사용자에게 노출되지 않습니다. (Contributed by Aviv Palivoda in bpo-30262 [https://bugs.python.org/issue?@action=redirect&bpo=30262].)

fileinput.input()과 fileinput.FileInput()의 bufsize 키워드 인자는 무시 되었고 파이썬 3.6부터 폐지되었으며, 이제 제거되었습니다. bpo-36952 [https://bugs.python.org/issue?@action=redirect&bpo=36952] (Contributed by Matthias Bussonnier.)

파이썬 3.7에서 폐지된 sys.set_coroutine_wrapper()와 sys.get_coroutine_wrapper() 함수는 제거되었습니다; bpo-36933 [https://bugs.python.org/issue?@action=redirect&bpo=36933] (Contributed by Matthias Bussonnier.)

파이썬 3.8로 이식하기

이 절에서는 여러분의 코드 수정을 요구할 수도 있는 이전에 설명한 변경 사항과 다른 버그 수정 사항을 나열합니다.

파이썬 동작의 변경

일드 표현식(yield와 yield from 절 모두)은 이제 컴프리헨션과 제너레이터 표현식에서 허용되지 않습니다 (가장 왼쪽 for 절의 이터러블 표현식 제외). (Contributed by Serhiy Storchaka in bpo-10544 [https://bugs.python.org/issue?@action=redirect&bpo=10544].)

아이덴티티 검사(is와 is not)가 특정 형의 리터럴(예를 들어, 문자열, 숫자)과 함께 사용될 때 컴파일러는 이제 SyntaxWarning을 생성합니다. 이들은 종종 CPython에서 우연히 작동할 수 있지만, 언어 명세에 의해 보장되지는 않습니다. 이 경고는 사용자가 동등 검사(==와 !=)를 대신 사용하도록 권장합니다. (Contributed by Serhiy Storchaka in bpo-34850 [https://bugs.python.org/issue?@action=redirect&bpo=34850].)

CPython 인터프리터는 때에 따라 예외를 삼킬 수 있습니다. 파이썬 3.8에서는 이런 경우가 덜 발생합니다. 특히, 형 딕셔너리에서 어트리뷰트를 가져올 때 발생하는 예외는 더는 무시되지 않습니다. (Contributed by Serhiy Storchaka in bpo-35459 [https://bugs.python.org/issue?@action=redirect&bpo=35459].)

내장형 bool, int, float, complex 및 표준 라이브러리의 일부 클래스에서 __str__ 구현을 제거했습니다. 이제 이들은 object에서 __str__()을 상속합니다. 결과적으로, 이러한 클래스의 서브 클래스에서 __repr__() 메서드를 정의하면 문자열 표현에 영향을 줍니다. (Contributed by Serhiy Storchaka in bpo-36793 [https://bugs.python.org/issue?@action=redirect&bpo=36793].)

On AIX, sys.platform doesn’t contain the major version anymore. It is always 'aix', instead of 'aix3' .. 'aix7'. Since older Python versions include the version number, so it is recommended to always use sys.platform.startswith('aix'). (Contributed by M. Felt in bpo-36588 [https://bugs.python.org/issue?@action=redirect&bpo=36588].)

PyEval_AcquireLock() and PyEval_AcquireThread() now terminate the current thread if called while the interpreter is finalizing, making them consistent with PyEval_RestoreThread(), Py_END_ALLOW_THREADS(), and PyGILState_Ensure(). If this behavior is not desired, guard the call by checking _Py_IsFinalizing() or sys.is_finalizing(). (Contributed by Joannah Nanjekye in bpo-36475 [https://bugs.python.org/issue?@action=redirect&bpo=36475].)

파이썬 API의 변경

os.getcwdb() 함수는 이제 윈도우에서 ANSI 코드 페이지가 아닌 UTF-8 인코딩을 사용합니다. 이유는 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오. 이 함수는 윈도우에서 더는 폐지되지 않았습니다. (Contributed by Victor Stinner in bpo-37412 [https://bugs.python.org/issue?@action=redirect&bpo=37412].)

subprocess.Popen은 이제 어떤 경우에 더 나은 성능을 위해 os.posix_spawn()을 사용할 수 있습니다. 리눅스용 윈도우 하위 시스템과 QEMU 사용자 에뮬레이션에서, os.posix_spawn()을 사용하는 Popen 생성자는 더는 “프로그램 누락”과 같은 에러에 예외를 발생시키지 않습니다. 대신 자식 프로세스는 0이 아닌 returncode로 실패합니다. (Contributed by Joannah Nanjekye and Victor Stinner in bpo-35537 [https://bugs.python.org/issue?@action=redirect&bpo=35537].)

subprocess.Popen의 preexec_fn 인자는 더는 서브 인터프리터와 호환되지 않습니다. 서브 인터프리터에서 매개 변수를 사용하면 RuntimeError가 발생합니다. (Contributed by Eric Snow in bpo-34651 [https://bugs.python.org/issue?@action=redirect&bpo=34651], modified by Christian Heimes in bpo-37951 [https://bugs.python.org/issue?@action=redirect&bpo=37951].)

imap.IMAP4.logout() 메서드는 더는 조용히 임의의 예외를 무시하지 않습니다. (Contributed by Victor Stinner in bpo-36348 [https://bugs.python.org/issue?@action=redirect&bpo=36348].)

파이썬 3.3부터 폐지된 이후로, platform.popen() 함수는 제거되었습니다: 대신 os.popen()을 사용하십시오. (Contributed by Victor Stinner in bpo-35345 [https://bugs.python.org/issue?@action=redirect&bpo=35345].)

statistics.mode() 함수는 다중 모드(multimodal) 데이터가 주어질 때 더는 예외를 발생시키지 않습니다. 대신, 입력 데이터에서 만나는 첫 번째 모드를 반환합니다. (Contributed by Raymond Hettinger in bpo-35892 [https://bugs.python.org/issue?@action=redirect&bpo=35892].)

tkinter.ttk.Treeview 클래스의 selection() 메서드는 더는 인자를 받아들이지 않습니다. 선택을 변경하기 위해 인자와 함께 사용하는 것은 파이썬 3.6에서 폐지되었습니다. 선택을 변경하려면 selection_set()과 같은 특화된 메서드를 사용하십시오. (Contributed by Serhiy Storchaka in bpo-31508 [https://bugs.python.org/issue?@action=redirect&bpo=31508].)

xml.dom.minidom 모듈의 writexml(), toxml() 및 toprettyxml() 메서드와 xml.etree의 write() 메서드는 이제 사용자가 지정한 어트리뷰트 순서를 보존합니다. (Contributed by Diego Rojas and Raymond Hettinger in bpo-34160 [https://bugs.python.org/issue?@action=redirect&bpo=34160].)

플래그 'r'로 열린 dbm.dumb 데이터베이스는 이제 읽기 전용입니다. 'r'과 'w' 플래그로 dbm.dumb.open()하면 더는 데이터베이스가 없을 때 만들지 않습니다. (Contributed by Serhiy Storchaka in bpo-32749 [https://bugs.python.org/issue?@action=redirect&bpo=32749].)

XMLParser의 서브 클래스에 정의된 doctype() 메서드는 더는 호출되지 않으며 DeprecationWarning 대신 RuntimeWarning을 방출합니다. XML doctype 선언을 처리하려면 대상에 doctype() 메서드를 정의하십시오. (Contributed by Serhiy Storchaka in bpo-29209 [https://bugs.python.org/issue?@action=redirect&bpo=29209].)

사용자 지정 메타 클래스가 type.__new__에 전달된 이름 공간에 __classcell__ 항목을 제공하지 않으면 이제 RuntimeError가 발생합니다. 파이썬 3.6–3.7에서는 DeprecationWarning이 방출되었습니다. (Contributed by Serhiy Storchaka in bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722].)

cProfile.Profile 클래스는 이제 컨텍스트 관리자로 사용할 수 있습니다. (Contributed by Scott Sanderson in bpo-29235 [https://bugs.python.org/issue?@action=redirect&bpo=29235].)

shutil.copyfile(), shutil.copy(), shutil.copy2(), shutil.copytree() 및 shutil.move()는 플랫폼 특정 “고속 복사(fast-copy)” 시스템 호출을 사용합니다 (플랫폼 의존적 효율적인 복사 연산 절을 참조하십시오).

윈도우에서 shutil.copyfile() 기본 버퍼 크기가 16 KiB에서 1 MiB로 변경되었습니다.

PyGC_Head 구조체가 완전히 변경되었습니다. 구조체 멤버를 건드리는 모든 코드는 다시 작성해야 합니다. (bpo-33597 [https://bugs.python.org/issue?@action=redirect&bpo=33597] 참조.)

PyInterpreterState 구조체는 “내부” 헤더 파일(구체적으로 Include/internal/pycore_pystate.h)로 이동했습니다. 불투명한 PyInterpreterState는 공용 API(와 안정 ABI)의 일부로 계속 사용할 수 있습니다. 설명서는 구조체의 필드가 공용이 아니라고 말하고 있으니, 아무도 해당 필드를 사용하지 않기를 바랍니다. 그러나, 하나 이상의 내부 필드에 의지하고 대안이 없으면 BPO 이슈를 여십시오. 조정을 돕기 위해 노력할 것입니다 (공용 API에 접근 함수를 추가하는 것도 가능합니다). (bpo-35886 [https://bugs.python.org/issue?@action=redirect&bpo=35886]을 참조하십시오.)

mmap.flush() 메서드는 이제 모든 플랫폼에서 성공 시 None을 반환하고 에러 시 예외를 발생시킵니다. 이전에는, 그 동작이 플랫폼에 따라 달랐습니다: 윈도우에서 성공 시 0이 아닌 값이 반환되었습니다; 에러 시 0이 반환되었습니다. 유닉스에서 성공 시 0 값이 반환되었습니다; 에러 시 예외가 발생했습니다. (Contributed by Berker Peksag in bpo-2122 [https://bugs.python.org/issue?@action=redirect&bpo=2122].)

xml.dom.minidom과 xml.sax 모듈은 기본적으로 더는 외부 엔티티를 처리하지 않습니다. (Contributed by Christian Heimes in bpo-17239 [https://bugs.python.org/issue?@action=redirect&bpo=17239].)

읽기 전용 dbm 데이터베이스(dbm.dumb, dbm.gnu 또는 dbm.ndbm)에서 키를 삭제하면 KeyError 대신 error(dbm.dumb.error, dbm.gnu.error 또는 dbm.ndbm.error)를 발생시킵니다. (Contributed by Xiang Zhang in bpo-33106 [https://bugs.python.org/issue?@action=redirect&bpo=33106].)

리터럴을 위해 단순화된 AST. 모든 상수는 ast.Constant 인스턴스로 표시됩니다. 이전 클래스 Num, Str, Bytes, NameConstant 및 Ellipsis를 인스턴스 화하면 Constant 인스턴스가 반환됩니다. (Contributed by Serhiy Storchaka in bpo-32892 [https://bugs.python.org/issue?@action=redirect&bpo=32892].)

윈도우에서 expanduser()는 이제 USERPROFILE 환경 변수를 선호하며 일반적으로 일반 사용자 계정에 설정되지 않는 HOME을 사용하지 않습니다. (Contributed by Anthony Sottile in bpo-36264 [https://bugs.python.org/issue?@action=redirect&bpo=36264].)

asyncio.CancelledError 예외는 이제 Exception이 아닌 BaseException을 상속하고, 더는 concurrent.futures.CancelledError를 상속하지 않습니다. (Contributed by Yury Selivanov in bpo-32528 [https://bugs.python.org/issue?@action=redirect&bpo=32528].)

asyncio.wait_for() 함수는 이제 asyncio.Task 인스턴스를 사용할 때 취소를 올바르게 기다립니다. 이전에는, timeout에 도달하면 취소되어 즉시 반환되었습니다. (Contributed by Elvis Pranskevichus in bpo-32751 [https://bugs.python.org/issue?@action=redirect&bpo=32751].)

asyncio.BaseTransport.get_extra_info() 함수는 이제 ‘socket’이 name 매개 변수로 전달될 때 안전하게 사용할 수 있는 소켓 객체를 반환합니다. (Contributed by Yury Selivanov in bpo-37027 [https://bugs.python.org/issue?@action=redirect&bpo=37027].)

asyncio.BufferedProtocol는 졸업해서 안정 API가 되었습니다.

윈도우에서 ctypes로 로드된 확장 모듈과 DLL에 대한 DLL 종속성이 이제 더 안전하게 처리됩니다. 시스템 경로, DLL이나 PYD 파일이 들어 있는 디렉터리 및 add_dll_directory()로 추가된 디렉터리만 로드 시간 종속성을 위해 검색합니다. 특히, PATH와 현재 작업 디렉터리는 더는 사용되지 않으며, 이러한 것들에 대한 수정은 더는 일반 DLL 결정(resolution)에 영향을 주지 않습니다. 여러분의 응용 프로그램이 이러한 메커니즘에 의존한다면, add_dll_directory()가 있는지 확인하고, 있다면 이를 사용하여 라이브러리를 로드하는 동안 DLL 디렉터리를 추가하십시오. 윈도우 7 사용자는 윈도우 업데이트 KB2533623이 설치되었는지 확인해야 합니다 (이는 설치 프로그램에서도 확인합니다). (Contributed by Steve Dower in bpo-36085 [https://bugs.python.org/issue?@action=redirect&bpo=36085].)

pgen과 관련된 헤더 파일과 함수는 순수 파이썬 구현으로 대체 된 후에 제거되었습니다. (Contributed by Pablo Galindo in bpo-36623 [https://bugs.python.org/issue?@action=redirect&bpo=36623].)

types.CodeType은 PEP 570 [https://peps.python.org/pep-0570/]에 정의된 위치 전용 인자를 지원하기 위해 생성자의 두 번째 위치에 새 매개 변수(posonlyargcount)를 갖습니다. 첫 번째 인자(argcount)는 이제 위치 인자의 총수(위치 전용 인자 포함)를 나타냅니다. types.CodeType의 새로운 replace() 메서드를 사용하면 코드가 미래에도 안전하게 만들 수 있습니다.

The parameter digestmod for hmac.new() no longer uses the MD5 digest by default.

C API의 변경

The PyCompilerFlags structure got a new cf_feature_version field. It should be initialized to PY_MINOR_VERSION. The field is ignored by default, and is used if and only if PyCF_ONLY_AST flag is set in cf_flags. (Contributed by Guido van Rossum in bpo-35766 [https://bugs.python.org/issue?@action=redirect&bpo=35766].)

The PyEval_ReInitThreads() function has been removed from the C API. It should not be called explicitly: use PyOS_AfterFork_Child() instead. (Contributed by Victor Stinner in bpo-36728 [https://bugs.python.org/issue?@action=redirect&bpo=36728].)

유닉스에서, C 확장은 더는 안드로이드와 Cygwin을 제외하고는 libpython에 링크되지 않습니다. 파이썬이 내장될 때, libpython은 RTLD_LOCAL이 아니라 RTLD_GLOBAL로 로드되어야 합니다. 이전에는, RTLD_LOCAL을 사용하여, Modules/Setup의 *shared* 섹션에 의해 빌드된 표준 라이브러리의 C 확장과 같이 libpython에 링크되지 않은 C 확장을 로드할 수 없었습니다. (Contributed by Victor Stinner in bpo-21536 [https://bugs.python.org/issue?@action=redirect&bpo=21536].)

PY_SSIZE_T_CLEAN이 정의되지 않은 상태에서 값을 구문 분석하거나 빌드할 때(예를 들어, PyArg_ParseTuple(), Py_BuildValue(), PyObject_CallFunction() 등) 포맷의 # 변형을 사용하면 DeprecationWarning이 발생합니다. 3.10이나 4.0에서 제거됩니다. 자세한 내용은 인자 구문 분석과 값 구축를 참조하십시오. (Contributed by Inada Naoki in bpo-36381 [https://bugs.python.org/issue?@action=redirect&bpo=36381].)

힙에 할당된 형(가령 PyType_FromSpec()으로 만들어진 것들)의 인스턴스는 해당 형 객체에 대한 참조를 보유합니다. 이러한 형 객체의 참조 횟수를 늘리는 것이 PyType_GenericAlloc()에서 더 저수준 함수 PyObject_Init()와 PyObject_INIT()로 옮겨졌습니다. 이렇게 하면 PyType_FromSpec()을 통해 만들어진 형이, 관리되는 코드의 다른 클래스처럼 작동합니다.

Statically allocated types are not affected.

대다수의 경우, 부작용이 없어야 합니다. 그러나, 인스턴스를 할당한 후 수동으로 참조 횟수를 늘리는 형(아마도 버그를 회피하기 위해)이 이제 불멸이 될 수 있습니다. 이를 피하고자, 이런 클래스는 인스턴스 할당 해제 중에 형 객체에 Py_DECREF를 호출할 필요가 있습니다.

이러한 형들을 3.8로 올바르게 이식하려면, 다음 변경 사항을 적용하십시오:

Remove Py_INCREF on the type object after allocating an instance - if any. This may happen after calling PyObject_New, PyObject_NewVar, PyObject_GC_New(), PyObject_GC_NewVar(), or any other custom allocator that uses PyObject_Init() or PyObject_INIT().

예:

static foo_struct *
foo_new(PyObject *type) {
    foo_struct *foo = PyObject_GC_New(foo_struct, (PyTypeObject *) type);
    if (foo == NULL)
        return NULL;
#if PY_VERSION_HEX < 0x03080000
    // Workaround for Python issue 35810; no longer necessary in Python 3.8
    PY_INCREF(type)
#endif
    return foo;
}

힙에 할당되는 형의 모든 사용자 정의 tp_dealloc 함수가 형의 참조 횟수를 감소시키도록 하십시오.

예:

static void
foo_dealloc(foo_struct *instance) {
    PyObject *type = Py_TYPE(instance);
    PyObject_GC_Del(instance);
#if PY_VERSION_HEX >= 0x03080000
    // This was not needed before Python 3.8 (Python issue 35810)
    Py_DECREF(type);
#endif
}

(Contributed by Eddie Elizondo in bpo-35810 [https://bugs.python.org/issue?@action=redirect&bpo=35810].)

Py_DEPRECATED() 매크로는 MSVC 용으로 구현되었습니다. 매크로는 이제 기호 이름 앞에 놓여야 합니다.

예:

Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);

(Contributed by Zackery Spytz in bpo-33407 [https://bugs.python.org/issue?@action=redirect&bpo=33407].)

The interpreter does not pretend to support binary compatibility of extension types across feature releases, anymore. A PyTypeObject exported by a third-party extension module is supposed to have all the slots expected in the current Python version, including tp_finalize (Py_TPFLAGS_HAVE_FINALIZE is not checked anymore before reading tp_finalize).

(Contributed by Antoine Pitrou in bpo-32388 [https://bugs.python.org/issue?@action=redirect&bpo=32388].)

The functions PyNode_AddChild() and PyParser_AddToken() now accept two additional int arguments end_lineno and end_col_offset.

MinGW 도구가 python38.dll에 대해 직접 링크할 수 있도록 허용하는 libpython38.a 파일은 더는 일반 윈도우 배포에 포함되지 않습니다. 이 파일이 필요하면, MinGW binutils 패키지의 일부인 gendef와 dlltool 도구로 생성할 수 있습니다:

gendef - python38.dll > tmp.def
dlltool --dllname python38.dll --def tmp.def --output-lib libpython38.a

설치된 pythonXY.dll의 위치는 윈도우의 설치 옵션과 버전 및 언어에 따라 다릅니다. 자세한 내용은 윈도우에서 파이썬 사용하기를 참조하십시오. 결과 라이브러리는 pythonXY.lib(일반적으로 파이썬 설치 환경의 libs 디렉터리입니다)와 같은 디렉터리에 위치해야 합니다.

(Contributed by Steve Dower in bpo-37351 [https://bugs.python.org/issue?@action=redirect&bpo=37351].)

CPython 바이트 코드 변경

인터프리터 루프는 블록 스택을 언 롤링하는 로직을 컴파일러로 이동시킴으로써 단순화되었습니다. 컴파일러는 이제 값 스택을 조정하고 break, continue 및 return에 대한 정리 코드를 호출하는 명시적인 명령을 출력합니다.

Removed opcodes BREAK_LOOP, CONTINUE_LOOP, SETUP_LOOP and SETUP_EXCEPT. Added new opcodes ROT_FOUR, BEGIN_FINALLY, CALL_FINALLY and POP_FINALLY. Changed the behavior of END_FINALLY and WITH_CLEANUP_START.

(Contributed by Mark Shannon, Antoine Pitrou and Serhiy Storchaka in bpo-17611 [https://bugs.python.org/issue?@action=redirect&bpo=17611].)

async for 루프에서 다음 항목을 await 할 때 발생하는 예외를 처리하기 위한 새로운 옵코드 END_ASYNC_FOR가 추가되었습니다. (Contributed by Serhiy Storchaka in bpo-33041 [https://bugs.python.org/issue?@action=redirect&bpo=33041].)

MAP_ADD는 이제 값을 스택의 첫 번째 요소로, 키를 두 번째 요소로 기대합니다. 이 변경은 PEP 572 [https://peps.python.org/pep-0572/]의 제안에 따라, 딕셔너리 컴프리헨션에서 키가 값보다 항상 먼저 평가되도록 하기 위해 만들어졌습니다. (Contributed by Jörn Heissler in bpo-35224 [https://bugs.python.org/issue?@action=redirect&bpo=35224].)

데모와 도구

변수를 액세스하는 다양한 방법의 시간을 측정하기 위한 벤치마크 스크립트를 추가했습니다: Tools/scripts/var_access_benchmark.py. (Contributed by Raymond Hettinger in bpo-35884 [https://bugs.python.org/issue?@action=redirect&bpo=35884].)

다음은 파이썬 3.3 이후의 성능 향상에 대한 요약입니다:

Python version                       3.3     3.4     3.5     3.6     3.7     3.8
--------------                       ---     ---     ---     ---     ---     ---

Variable and attribute read access:
    read_local                       4.0     7.1     7.1     5.4     5.1     3.9
    read_nonlocal                    5.3     7.1     8.1     5.8     5.4     4.4
    read_global                     13.3    15.5    19.0    14.3    13.6     7.6
    read_builtin                    20.0    21.1    21.6    18.5    19.0     7.5
    read_classvar_from_class        20.5    25.6    26.5    20.7    19.5    18.4
    read_classvar_from_instance     18.5    22.8    23.5    18.8    17.1    16.4
    read_instancevar                26.8    32.4    33.1    28.0    26.3    25.4
    read_instancevar_slots          23.7    27.8    31.3    20.8    20.8    20.2
    read_namedtuple                 68.5    73.8    57.5    45.0    46.8    18.4
    read_boundmethod                29.8    37.6    37.9    29.6    26.9    27.7

Variable and attribute write access:
    write_local                      4.6     8.7     9.3     5.5     5.3     4.3
    write_nonlocal                   7.3    10.5    11.1     5.6     5.5     4.7
    write_global                    15.9    19.7    21.2    18.0    18.0    15.8
    write_classvar                  81.9    92.9    96.0   104.6   102.1    39.2
    write_instancevar               36.4    44.6    45.8    40.0    38.9    35.5
    write_instancevar_slots         28.7    35.6    36.1    27.3    26.6    25.7

Data structure read access:
    read_list                       19.2    24.2    24.5    20.8    20.8    19.0
    read_deque                      19.9    24.7    25.5    20.2    20.6    19.8
    read_dict                       19.7    24.3    25.7    22.3    23.0    21.0
    read_strdict                    17.9    22.6    24.3    19.5    21.2    18.9

Data structure write access:
    write_list                      21.2    27.1    28.5    22.5    21.6    20.0
    write_deque                     23.8    28.7    30.1    22.7    21.8    23.5
    write_dict                      25.9    31.4    33.3    29.3    29.2    24.7
    write_strdict                   22.9    28.4    29.9    27.5    25.2    23.1

Stack (or queue) operations:
    list_append_pop                144.2    93.4   112.7    75.4    74.2    50.8
    deque_append_pop                30.4    43.5    57.0    49.4    49.2    42.5
    deque_append_popleft            30.8    43.7    57.3    49.7    49.7    42.8

Timing loop:
    loop_overhead                    0.3     0.5     0.6     0.4     0.3     0.3

The benchmarks were measured on an Intel® Core™ i7-4960HQ processor [https://ark.intel.com/content/www/us/en/ark/products/76088/intel-core-i7-4960hq-processor-6m-cache-up-to-3-80-ghz.html] running the macOS 64-bit builds found at python.org [https://www.python.org/downloads/macos/]. The benchmark script displays timings in nanoseconds.

파이썬 3.8.1의 주목할만한 변경 사항

심각한 보안 문제로 인해, asyncio.loop.create_datagram_endpoint()의 reuse_address 매개 변수는 더는 지원되지 않습니다. 이것은 UDP에서 소켓 옵션 SO_REUSEADDR의 동작 때문입니다. 자세한 내용은 loop.create_datagram_endpoint() 설명서를 참조하십시오. (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228].)

Notable changes in Python 3.8.2

Fixed a regression with the ignore callback of shutil.copytree(). The argument types are now str and List[str] again. (Contributed by Manuel Barkhau and Giampaolo Rodola in gh-83571 [https://github.com/python/cpython/issues/83571].)

Notable changes in Python 3.8.3

The constant values of future flags in the __future__ module are updated in order to prevent collision with compiler flags. Previously PyCF_ALLOW_TOP_LEVEL_AWAIT was clashing with CO_FUTURE_DIVISION. (Contributed by Batuhan Taskaya in gh-83743 [https://github.com/python/cpython/issues/83743])

파이썬 3.8.8의 주목할만한 변경 사항

Earlier Python versions allowed using both ; and & as query parameter separators in urllib.parse.parse_qs() and urllib.parse.parse_qsl(). Due to security concerns, and to conform with newer W3C recommendations, this has been changed to allow only a single separator key, with & as the default. This change also affects cgi.parse() and cgi.parse_multipart() as they use the affected functions internally. For more details, please see their respective documentation. (Contributed by Adam Goldschmidt, Senthil Kumaran and Ken Jin in bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967].)

Notable changes in Python 3.8.9

A security fix alters the ftplib.FTP behavior to not trust the IPv4 address sent from the remote server when setting up a passive data channel. We reuse the ftp server IP address instead. For unusual code requiring the old behavior, set a trust_server_pasv_ipv4_address attribute on your FTP instance to True. (See gh-87451 [https://github.com/python/cpython/issues/87451])

Notable changes in Python 3.8.10

macOS 11.0 (Big Sur) and Apple Silicon Mac support

As of 3.8.10, Python now supports building and running on macOS 11 (Big Sur) and on Apple Silicon Macs (based on the ARM64 architecture). A new universal build variant, universal2, is now available to natively support both ARM64 and Intel 64 in one set of executables. Note that support for “weaklinking”, building binaries targeted for newer versions of macOS that will also run correctly on older versions by testing at runtime for missing features, is not included in this backport from Python 3.9; to support a range of macOS versions, continue to target for and build on the oldest version in the range.

(Originally contributed by Ronald Oussoren and Lawrence D’Anna in gh-85272 [https://github.com/python/cpython/issues/85272], with fixes by FX Coudert and Eli Rykoff, and backported to 3.8 by Maxime Bélanger and Ned Deily)

Notable changes in Python 3.8.10

urllib.parse

The presence of newline or tab characters in parts of a URL allows for some forms of attacks. Following the WHATWG specification that updates RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html], ASCII newline \n, \r and tab \t characters are stripped from the URL by the parser in urllib.parse preventing such attacks. The removal characters are controlled by a new module level variable urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE. (See bpo-43882 [https://bugs.python.org/issue?@action=redirect&bpo=43882])

Notable changes in Python 3.8.12

파이썬 API의 변경

Starting with Python 3.8.12 the ipaddress module no longer accepts any leading zeros in IPv4 address strings. Leading zeros are ambiguous and interpreted as octal notation by some libraries. For example the legacy function socket.inet_aton() treats leading zeros as octal notation. glibc implementation of modern inet_pton() does not accept any leading zeros.

(Originally contributed by Christian Heimes in bpo-36384 [https://bugs.python.org/issue?@action=redirect&bpo=36384], and backported to 3.8 by Achraf Merzouki.)

Notable security feature in 3.8.14

Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735]. This limit can be configured or disabled by environment variable, command line flag, or sys APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.

Notable changes in 3.8.17

tarfile

The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details. In Python 3.12, use without the filter argument will show a DeprecationWarning. In Python 3.14, the default will switch to 'data'. (Contributed by Petr Viktorin in PEP 706 [https://peps.python.org/pep-0706/].)

파이썬 3.7의 새로운 기능

편집자:

Elvis Pranskevichus <elvis@magic.io>

이 기사에서는 파이썬 3.6과 비교하여 3.7의 새로운 기능에 관해 설명합니다. 파이썬 3.7은 2018년 6월 27일에 배포되었습니다. 자세한 내용은 changelog 를 참조하세요.

요약 – 배포 주요 사항

새로운 문법 기능:

PEP 563, 형 어노테이션의 지연된 평가.

이전 버전과 호환되지 않는 문법 변경:

async와 await 는 이제 예약 키워드입니다.

새 라이브러리 모듈:

contextvars: PEP 567 – 컨텍스트 변수

dataclasses: PEP 557 – 데이터 클래스

importlib.resources

새로운 내장 기능:

PEP 553, 새로운 breakpoint() 함수.

파이썬 데이터 모델 개선:

PEP 562, 모듈 어트리뷰트에 대한 액세스의 사용자 정의.

PEP 560, typing 모듈과 제네릭 형에 대한 코어 지원.

dict 객체의 삽입 순서 보존 특성을 파이썬 언어 규격의 공식적인 일부로 선언했습니다 [https://mail.python.org/pipermail/python-dev/2017-December/151283.html].

표준 라이브러리의 현저한 개선:

asyncio 모듈에 새 기능과 현저한 사용성 및 성능 개선 이 추가되었습니다.

time 모듈은 나노초 해상도의 함수 지원을 얻었습니다.

CPython 구현 개선:

ASCII를 기본 텍스트 인코딩으로 사용하지 않기:

PEP 538, 레거시 C 로케일 강제 변경

PEP 540, 강제 UTF-8 실행시간 모드

PEP 552, 결정적 .pycs

새로운 파이썬 개발 모드

PEP 565, 개선된 DeprecationWarning 처리

C API 개선 사항:

PEP 539, 스레드-로컬 저장소를 위한 새로운 C API

설명서 개선 사항:

PEP 545, 파이썬 설명서 번역

새로운 설명서 번역: 일본어 [https://docs.python.org/ja/], 프랑스어 [https://docs.python.org/fr/], 한국어 [https://docs.python.org/ko/].

이 배포는 많은 영역에서 주목할만한 성능 향상을 제공합니다. 최적화 섹션에 자세히 나와 있습니다.

이전 파이썬 배포와의 호환성에 영향을 줄 수 있는 변경 사항 목록은 파이썬 3.7로 이식하기 섹션을 참조하십시오.

새로운 기능

PEP 563 : 어노테이션의 지연된 평가

파이썬에서 형 힌트의 출현은 PEP 3107 [https://peps.python.org/pep-3107/]에서 추가되고 PEP 526 [https://peps.python.org/pep-0526/]에서 더욱 다듬어진 어노테이션의 두 가지 사용성 문제를 드러냈습니다:

어노테이션은 현재 스코프에서 이미 사용 가능한 이름 만 사용할 수 있습니다. 즉, 어떤 종류의 전방 참조도 지원하지 않았습니다; 그리고

소스 코드에 어노테이션을 붙이는 것은 파이썬 프로그램의 시작 시간에 악영향을 미쳤습니다.

이 두 가지 문제는 어노테이션 평가를 지연시키는 것으로 해결됩니다. 정의 시간에 어노테이션의 표현식을 실행하는 코드를 컴파일하는 대신, 컴파일러는 해당 표현식의 AST와 동등한 문자열 형식으로 어노테이션을 저장합니다. 필요하다면, 실행시간에 typing.get_type_hints() 를 사용하여 어노테이션을 해석 할 수 있습니다. 이것이 필수적이지 않은 일반적인 경우에는, 어노테이션을 싸게 저장할 수 있고 (짧은 문자열은 인터프리터에 의해 한 번만 만들어지기 때문입니다), 시작 시간을 더 빠르게 할 수 있습니다.

사용성 측면에서, 이제 어노테이션이 전방 참조를 지원하므로 다음 문법이 유효합니다:

class C:
    @classmethod
    def from_string(cls, source: str) -> C:
        ...

    def validate_b(self, obj: B) -> bool:
        ...

class B:
    ...

이 변경으로 인해 호환성이 깨지기 때문에, 파이썬 3.7에서 새 동작은 __future__ 임포트를 사용하여 모듈별로 새로운 동작을 활성화해야 합니다:

from __future__ import annotations

파이썬 3.10에서는 기본값이 됩니다.

더 보기

PEP 563 [https://peps.python.org/pep-0563/] – 어노테이션의 지연된 평가

Łukasz Langa가 작성하고 구현한 PEP.

PEP 538: 레거시 C 로케일 강제 변경

파이썬 3시리즈에서 진행 중인 과제는, 윈도우 이외의 플랫폼에서 기본 C 또는 POSIX 로케일 사용으로 인해 묵시적으로 가정되는 “7-비트 ASCII” 텍스트 인코딩을 처리하기 위한 적절한 기본 전략을 결정하는 것입니다.

새 PYTHONCOERCECLOCALE 환경 변수의 설명서에 설명되어있듯이, PEP 538 [https://peps.python.org/pep-0538/] 은 기본 인터프리터 명령행 인터페이스를 갱신하여, 사용 가능한 UTF-8 기반 로케일로 자동으로 강제 변경합니다. 이런 식으로 LC_CTYPE 을 자동 설정하는 것은, 핵심 인터프리터와 로케일을 인식하는 C 확장 (가령 readline) 모두 기본 텍스트 인코딩으로 ASCII 대신 UTF-8을 가정하게 된다는 뜻입니다.

PEP 11 [https://peps.python.org/pep-0011/] 의 플랫폼 지원 정의 역시 전체 텍스트 처리 지원을 적절히 구성된 비 ASCII 기반 로케일로 제한하도록 갱신되었습니다.

이 변경의 일부로, 이제 정의된 강제 변경 대상 로케일(현재 C.UTF-8, C.utf8, UTF-8)을 사용할 때, stdin 과 stdout 의 기본 에러 처리기는 (strict 대신) surrogateescape 입니다. stderr 의 기본 에러 처리기는 로케일에 관계없이 계속 backslashreplace 입니다.

로케일 강제 변경은 기본적으로 조용히 일어나지만, 로케일 관련 통합 문제를 디버깅하는 데 도움을 주기 위해 PYTHONCOERCECLOCALE=warn 를 설정해서 (stderr 로 직접 출력되는) 명시적 경고를 요청할 수 있습니다. 또한, 이 설정은 핵심 인터프리터가 초기화될 때 레거시 C 로케일이 활성 상태로 남아 있으면 파이썬 런타임이 경고를 하도록 만듭니다.

PEP 538 [https://peps.python.org/pep-0538/] 의 로케일 강제 변환이 (비 파이썬 응용 프로그램과 이전 버전의 파이썬을 실행하는 경우를 포함하는) 자식 프로세스뿐만 아니라 (GNU readline 같은) 확장 모듈에도 영향을 주는 장점이 있지만, 실행 중인 시스템에 적절한 대상 로케일이 있어야 한다는 단점이 있습니다. 적절한 대상 로케일을 사용할 수 없는 경우(예를 들어, RHEL/CentOS 7에서 발생하듯이)를 더 잘 처리하기 위해, 파이썬 3.7은 PEP 540: 강제 UTF-8 실행시간 모드 또한 구현합니다.

더 보기

PEP 538 [https://peps.python.org/pep-0538/] – 레거시 C 로케일을 UTF-8 기반 로케일로 강제 변경

Nick Coghlan 이 작성하고 구현한 PEP.

PEP 540: 강제 UTF-8 실행시간 모드

The new -X utf8 command line option and PYTHONUTF8 environment variable can be used to enable the Python UTF-8 Mode.

UTF-8 모드에서, CPython은 로케일 설정을 무시하고 기본적으로 UTF-8 인코딩을 사용합니다. sys.stdin 과 sys.stdout 스트림의 에러 처리기는 surrogateescape 로 설정됩니다.

강제 UTF-8 모드는 임베디드 응용 프로그램의 로케일 설정을 변경하지 않고 임베디드 파이썬 인터프리터의 텍스트 처리 동작을 변경하는 데 사용할 수 있습니다.

PEP 540 [https://peps.python.org/pep-0540/] 의 UTF-8 모드는 실행 중인 시스템에서 사용할 수 있는 로케일에 관계없이 작동하는 이점이 있지만, (GNU readline 과 같은) 확장 모듈, 비 파이썬 응용 프로그램을 실행하는 자식 프로세스, 이전 버전의 파이썬을 실행하는 자식 프로세스에 영향을 주지 못하는 단점이 있습니다. 이러한 구성 요소와 통신 할 때 텍스트 데이터가 손상될 위험을 줄이기 위해 파이썬 3.7은 PEP 540: 강제 UTF-8 실행시간 모드 또한 구현합니다.

UTF-8 모드는 로케일이 C 또는 POSIX 이고, PEP 538 [https://peps.python.org/pep-0538/] 로케일 강제 변환이 UTF-8 기반 대안으로의 변경에 실패할 때 (그 실패가 PYTHONCOERCECLOCALE=0 설정 때문이든, LC_ALL 설정 때문이든, 적절한 대상 로케일이 없기 때문이든 무관하게) 기본적으로 활성화됩니다.

더 보기

PEP 540 [https://peps.python.org/pep-0540/] – 새로운 UTF-8 모드 추가

Victor Stinner가 작성하고 구현한 PEP

PEP 553: 내장 breakpoint()

파이썬 3.7에는 파이썬 디버거에 진입하는 쉽고 일관된 방식을 제공하는 새로운 내장 breakpoint() 함수가 포함되어 있습니다.

내장 breakpoint() 는 sys.breakpointhook() 을 호출합니다. 기본적으로, 후자는 pdb를 임포트 한 다음 pdb.set_trace() 를 호출합니다. 하지만, sys.breakpointhook() 을 여러분이 선택한 함수에 연결하면, breakpoint() 는 임의의 디버거에 진입할 수 있습니다. 또한, 환경 변수 PYTHONBREAKPOINT 를 여러분이 선택한 디버거의 콜러블로 설정할 수 있습니다. 내장 breakpoint() 를 완전히 비활성화하려면 PYTHONBREAKPOINT=0 를 설정하십시오.

더 보기

PEP 553 [https://peps.python.org/pep-0553/] – 내장 breakpoint()

Barry Warsaw가 작성하고 구현한 PEP

PEP 539: 스레드-로컬 저장소를 위한 새로운 C API

While Python provides a C API for thread-local storage support; the existing Thread Local Storage (TLS) API has used int to represent TLS keys across all platforms. This has not generally been a problem for officially support platforms, but that is neither POSIX-compliant, nor portable in any practical sense.

PEP 539 [https://peps.python.org/pep-0539/] changes this by providing a new Thread Specific Storage (TSS) API to CPython which supersedes use of the existing TLS API within the CPython interpreter, while deprecating the existing API. The TSS API uses a new type Py_tss_t instead of int to represent TSS keys–an opaque type the definition of which may depend on the underlying TLS implementation. Therefore, this will allow to build CPython on platforms where the native TLS key is defined in a way that cannot be safely cast to int.

Note that on platforms where the native TLS key is defined in a way that cannot be safely cast to int, all functions of the existing TLS API will be no-op and immediately return failure. This indicates clearly that the old API is not supported on platforms where it cannot be used reliably, and that no effort will be made to add such support.

더 보기

PEP 539 [https://peps.python.org/pep-0539/] – CPython의 스레드-로컬 저장소를 위한 새로운 C-API

Erik M. Bray가 작성하고 Masayuki Yamamoto가 구현한 PEP.

PEP 562: 모듈 어트리뷰트에 대한 액세스 사용자 정의

파이썬 3.7은 모듈에, 발견되지 않는 어트리뷰트마다 호출되는 __getattr__() 을 정의할 수 있도록 합니다. 이제 모듈에 __dir__() 도 정의할 수 있게 되었습니다.

이것이 유용한 전형적인 예는 모듈 어트리뷰트 폐지와 지연 로딩입니다.

더 보기

PEP 562 [https://peps.python.org/pep-0562/] – 모듈 __getattr__ 과 __dir__

Ivan Levkivskyi가 작성하고 구현한 PEP

PEP 564: 나노초 해상도의 새로운 시간 함수

The resolution of clocks in modern systems can exceed the limited precision of a floating-point number returned by the time.time() function and its variants. To avoid loss of precision, PEP 564 [https://peps.python.org/pep-0564/] adds six new “nanosecond” variants of the existing timer functions to the time module:

time.clock_gettime_ns()

time.clock_settime_ns()

time.monotonic_ns()

time.perf_counter_ns()

time.process_time_ns()

time.time_ns()

새로운 함수는 나노초의 수를 정숫값으로 반환합니다.

Measurements [https://peps.python.org/pep-0564/#annex-clocks-resolution-in-python] show that on Linux and Windows the resolution of time.time_ns() is approximately 3 times better than that of time.time().

더 보기

PEP 564 [https://peps.python.org/pep-0564/] – 나노초 해상도의 새로운 시간 함수 추가

Victor Stinner가 작성하고 구현한 PEP

PEP 565: __main__ 의 DeprecationWarning 표시

DeprecationWarning 의 기본 처리 방식이 변경되어, 이러한 경고가 다시 한번 기본적으로 표시됩니다. 하지만, 이를 발생시킨 코드가 __main__ 모듈에서 직접 실행될 때만 표시됩니다. 결과적으로, 단일 파일 스크립트 개발자와 파이썬을 대화식으로 사용하는 개발자는 사용하는 API에 대한 폐지 경고를 다시 보게 되지만, 임포트되는 응용 프로그램, 라이브러리, 프레임웍 모듈에서 발생하는 폐지 경고는 계속 기본적으로 숨겨집니다.

이 변경으로 인해, 이제 표준 라이브러리는 개발자가 세 가지 다른 폐지 경고 동작 중 하나를 선택할 수 있도록 합니다:

FutureWarning: 기본적으로 항상 표시됩니다. 응용 프로그램 최종 사용자를 대상으로 하는 경고로 권장됩니다 (예, 폐지된 응용 프로그램 구성 설정).

DeprecationWarning: 기본적으로 __main__ 과 테스트 실행 시에 표시됩니다. 버전 업그레이드가 동작 변경이나 에러를 일으킬 수 있어서, 다른 파이썬 개발자를 대상으로 하는 경고로 권장됩니다.

PendingDeprecationWarning: 기본적으로 테스트 실행 시에만 표시됩니다. 향후 버전 업그레이드가 경고 범주를 DeprecationWarning 이나 FutureWarning으로 변경하게 될 경우를 위한 것입니다.

이전에는 DeprecationWarning 과 PendingDeprecationWarning 둘 다 테스트를 실행할 때만 볼 수 있었습니다. 주로 단일 파일 스크립트를 작성하거나 대화식으로 파이썬을 사용하는 개발자는 사용된 API가 호환되지 않는 방식으로 변경된 것을 보고 놀랄 수 있었습니다.

더 보기

PEP 565 [https://peps.python.org/pep-0565/] – __main__ 의 DeprecationWarning 표시

Nick Coghlan이 작성하고 구현한 PEP

PEP 560: typing 모듈과 제네릭 형에 대한 코어 지원

처음에는 PEP 484 [https://peps.python.org/pep-0484/] 가 핵심 CPython 인터프리터의 어떤 변경도 도입하지 않도록 설계되었습니다. 이제 형 힌트와 typing 모듈이 커뮤니티에서 광범위하게 사용되므로, 이 제한이 제거됩니다. PEP는 두 개의 특수 메서드 __class_getitem__() 과 __mro_entries__ 를 소개합니다. 이 메서드는 이제 typing 에 있는 대부분 클래스와 특수 구조물에서 사용됩니다. 그 결과로, 형과 관련된 여러 연산의 속도가 최대 7배까지 증가했고, 제네릭 형은 메타 클래스 충돌 없이 사용할 수 있으며, typing 모듈의 몇 가지 오랜 버그가 해결되었습니다.

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PEP 560 [https://peps.python.org/pep-0560/] – typing 모듈과 제네릭 형에 대한 코어 지원

Ivan Levkivskyi가 작성하고 구현한 PEP

PEP 552: 해시 기반 .pyc 파일

파이썬은 전통적으로 바이트 코드 캐시 파일(즉, .pyc 파일)의 최신성을 검사하기 위해, 소스 메타 데이터(최종 수정 타임스탬프와 크기)를 캐시 파일이 만들어질 때 헤더에 저장된 소스 메타 데이터와 비교했습니다. 효과적이지만, 이 무효화 방법에는 단점이 있습니다. 파일 시스템 타임스탬프가 너무 거친 경우, 파이썬은 소스 변경을 놓칠 수 있어 사용자 혼란을 낳을 수 있습니다. 또한, 캐시 파일에 타임스탬프를 갖는 것은 빌드 재현성 [https://reproducible-builds.org/] 과 콘텐츠 기반 빌드 시스템에서 문제가 됩니다.

PEP 552 [https://peps.python.org/pep-0552/] 는 소스 타임스탬프 대신 소스 파일의 해시가 소스 타임스탬프 대신 무효화에 사용될 수 있도록 pyc 형식을 확장합니다. 이러한 .pyc 파일을 “해시 기반”이라고 합니다. 기본적으로, 파이썬은 여전히 타임스탬프 기반 무효화를 사용하며 실행 시간에 해시 기반 .pyc 파일을 생성하지 않습니다. 해시 기반 .pyc 파일은 py_compile 또는 compileall로 만들 수 있습니다.

해시 기반 .pyc 파일에는 두 가지 변형이 있습니다: 검사형(checked)과 비검사형(unchecked). 파이썬은 검사형 해시 기반 .pyc 파일을 실행시간에 해당 소스 파일에 대해 유효성을 검사하지만, 비검사형 해시 기반 pyc에 대해서는 확인하지 않습니다. 비검사형 해시 기반 .pyc 파일은 파이썬 외부의 시스템(가령 빌드 시스템)이 .pyc 파일을 최신 상태로 유지하는 책임을 지는 환경에서 유용한 성능 최적화입니다.

자세한 정보는 캐시된 바이트 코드 무효화 를 보십시오.

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PEP 552 [https://peps.python.org/pep-0552/] – 결정적 pycs

Benjamin Peterson이 작성하고 구현한 PEP

PEP 545: 파이썬 설명서 번역

PEP 545 [https://peps.python.org/pep-0545/] 는 파이썬 설명서 번역을 만들고 유지하는 과정을 설명합니다.

세 가지 새로운 번역이 추가되었습니다:

일본어: https://docs.python.org/ja/

프랑스어: https://docs.python.org/fr/

한국어: https://docs.python.org/ko/

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PEP 545 [https://peps.python.org/pep-0545/] – 파이썬 설명서 번역

Julien Palard, Inada Naoki 및 Victor Stinner가 작성하고 구현한 PEP.

파이썬 개발 모드 (-X dev)

새 -X dev 명령행 옵션이나 새 PYTHONDEVMODE 환경 변수를 사용하여 파이썬 개발 모드를 활성화할 수 있습니다. 개발 모드에 있을 때, 파이썬은 기본적으로 활성화되기에는 너무 비싼 추가적인 실행 시간 검사를 수행합니다. 자세한 설명은 파이썬 개발 모드 설명서를 참조하십시오.

기타 언어 변경

await 표현식과 async for 절을 포함하는 컴프리헨션은 구현 문제로 인해 포맷 문자열 리터럴의 표현식에서 유효하지 않았습니다. 파이썬 3.7에서는 이 제한이 해제되었습니다.

이제 함수에 255개 이상의 인자를 전달할 수 있고, 함수는 255개 이상의 매개변수를 가질 수 있습니다. (Contributed by Serhiy Storchaka in bpo-12844 [https://bugs.python.org/issue?@action=redirect&bpo=12844] and bpo-18896 [https://bugs.python.org/issue?@action=redirect&bpo=18896].)

이제 bytes.fromhex() 와 bytearray.fromhex() 는 스페이스뿐만 아니라 모든 ASCII 공백을 무시합니다. (Contributed by Robert Xiao in bpo-28927 [https://bugs.python.org/issue?@action=redirect&bpo=28927].)

str, bytes, bytearray 는 새 isascii() 메서드에 대한 지원을 얻었습니다. 이 메서드를 사용하여 문자열이나 바이트열에 오직 ASCII 문자만 들어 있는지 검사할 수 있습니다. (Contributed by INADA Naoki in bpo-32677 [https://bugs.python.org/issue?@action=redirect&bpo=32677].)

이제 ImportError 는 from ... import ... 가 실패할 때 모듈 이름과 모듈 __file__ 경로를 출력합니다. (Contributed by Matthias Bussonnier in bpo-29546 [https://bugs.python.org/issue?@action=redirect&bpo=29546].)

이제 하위 모듈을 이름에 연결하는 절대 임포트가 수반되는 순환 임포트가 지원됩니다. (Contributed by Serhiy Storchaka in bpo-30024 [https://bugs.python.org/issue?@action=redirect&bpo=30024].)

이제 object.__format__(x, '') 는 format(str(self), '') 대신에 str(x) 과 동등합니다. (Contributed by Serhiy Storchaka in bpo-28974 [https://bugs.python.org/issue?@action=redirect&bpo=28974].)

In order to better support dynamic creation of stack traces, types.TracebackType can now be instantiated from Python code, and the tb_next attribute on tracebacks is now writable. (Contributed by Nathaniel J. Smith in bpo-30579 [https://bugs.python.org/issue?@action=redirect&bpo=30579].)

-m 스위치를 사용할 때, 이제 sys.path[0] 를 빈 디렉터리로 남겨두기보다는 전체 시작 디렉터리 경로로 확장됩니다 (빈 디렉터리를 남겨두면, 임포트가 일어날 때의 현재 작업 디렉터리로부터의 임포트가 가능해집니다) (Contributed by Nick Coghlan in bpo-33053 [https://bugs.python.org/issue?@action=redirect&bpo=33053].)

The new -X importtime option or the PYTHONPROFILEIMPORTTIME environment variable can be used to show the timing of each module import. (Contributed by Inada Naoki in bpo-31415 [https://bugs.python.org/issue?@action=redirect&bpo=31415].)

새 모듈

contextvars

새 contextvars 모듈과 새 C API 집합은 컨텍스트 변수 에 대한 지원을 도입합니다. 컨텍스트 변수는 개념적으로 스레드-로컬 변수와 유사합니다. TLS와 달리, 컨텍스트 변수는 비동기 코드를 올바르게 지원합니다.

asyncio와 decimal 모듈은 바로 사용할 수 있도록 컨텍스트 변수를 사용하고 지원하도록 업데이트되었습니다. 특히 활성 십진 컨텍스트는 이제 컨텍스트 변수에 저장되므로, 십진수 연산이 비동기 코드에서 올바른 컨텍스트에서 작동 할 수 있습니다.

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PEP 567 [https://peps.python.org/pep-0567/] – 컨텍스트 변수

Yury Selivanov가 작성하고 구현한 PEP

dataclasses

새 dataclass() 데코레이터는 데이터 클래스 를 선언하는 방법을 제공합니다. 데이터 클래스는 클래스 변수 어노테이션을 사용하여 어트리뷰트를 기술합니다. 생성자와 __repr__(), __eq__(), __hash__() 와 같은 다른 매직 메서드가 자동으로 생성됩니다.

예:

@dataclass
class Point:
    x: float
    y: float
    z: float = 0.0

p = Point(1.5, 2.5)
print(p)   # produces "Point(x=1.5, y=2.5, z=0.0)"

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PEP 557 [https://peps.python.org/pep-0557/] – 데이터 클래스

Eric V. Smith가 작성하고 구현한 PEP

importlib.resources

The new importlib.resources module provides several new APIs and one new ABC for access to, opening, and reading resources inside packages. Resources are roughly similar to files inside packages, but they needn’t be actual files on the physical file system. Module loaders can provide a get_resource_reader() function which returns a importlib.abc.ResourceReader instance to support this new API. Built-in file path loaders and zip file loaders both support this.

Contributed by Barry Warsaw and Brett Cannon in bpo-32248 [https://bugs.python.org/issue?@action=redirect&bpo=32248].

더 보기

importlib_resources [https://importlib-resources.readthedocs.io/en/latest/] – a PyPI backport for earlier Python versions.

개선된 모듈

argparse

새로운 ArgumentParser.parse_intermixed_args() 메서드는 옵션과 위치 인자의 혼합을 허용합니다. (Contributed by paul.j3 in bpo-14191 [https://bugs.python.org/issue?@action=redirect&bpo=14191].)

asyncio

asyncio 모듈은 많은 새로운 기능과 사용성 및 성능 개선이 추가되었습니다. 주목할만한 변경 사항은 다음과 같습니다:

새로운 잠정 asyncio.run() 함수는 자동으로 이벤트 루프를 생성하고 파괴함으로써 동기 코드에서 코루틴을 실행하는 데 사용될 수 있습니다. (Contributed by Yury Selivanov in bpo-32314 [https://bugs.python.org/issue?@action=redirect&bpo=32314].)

asyncio는 contextvars 에 대한 지원을 얻었습니다. loop.call_soon(), loop.call_soon_threadsafe(), loop.call_later(), loop.call_at() 및 Future.add_done_callback() 은 새로운 선택적 키워드-전용 context 매개 변수를 갖습니다. Tasks 는 이제 자신의 컨텍스트를 자동으로 추적합니다. 자세한 정보는 PEP 567 [https://peps.python.org/pep-0567/]을 보십시오. (Contributed by Yury Selivanov in bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436].)

새로운 asyncio.create_task() 함수가 asyncio.get_event_loop().create_task() 의 손쉬운 방법으로 추가되었습니다. (Contributed by Andrew Svetlov in bpo-32311 [https://bugs.python.org/issue?@action=redirect&bpo=32311].)

새로운 loop.start_tls() 메서드를 사용하여 기존 연결을 TLS로 업그레이드할 수 있습니다. (Contributed by Yury Selivanov in bpo-23749 [https://bugs.python.org/issue?@action=redirect&bpo=23749].)

새로운 loop.sock_recv_into() 메서드는 데이터를 직접 소켓에서 제공된 버퍼로 읽어 들여 데이터 복사를 줄일 수 있게 합니다. (Contributed by Antoine Pitrou in bpo-31819 [https://bugs.python.org/issue?@action=redirect&bpo=31819].)

The new asyncio.current_task() function returns the currently running Task instance, and the new asyncio.all_tasks() function returns a set of all existing Task instances in a given loop. The Task.current_task() and Task.all_tasks() methods have been deprecated. (Contributed by Andrew Svetlov in bpo-32250 [https://bugs.python.org/issue?@action=redirect&bpo=32250].)

새로운 잠정적 BufferedProtocol 클래스는 수신 버퍼를 수동으로 제어하여 스트리밍 프로토콜을 구현할 수 있게 합니다. (Contributed by Yury Selivanov in bpo-32251 [https://bugs.python.org/issue?@action=redirect&bpo=32251].)

새로운 asyncio.get_running_loop() 함수는 현재 실행 중인 루프를 반환하고, 루프가 실행되고 있지 않으면 RuntimeError 를 발생시킵니다. 이는 아무것도 실행되고 있지 않으면 새로 만드는 asyncio.get_event_loop() 과는 대조적입니다. (Contributed by Yury Selivanov in bpo-32269 [https://bugs.python.org/issue?@action=redirect&bpo=32269].)

새로운 StreamWriter.wait_closed() 코루틴 메서드는 스트림 작성자가 닫힐 때까지 기다릴 수 있습니다. 새로운 StreamWriter.is_closing() 메서드를 사용하여 작성기가 닫히고 있는지 판별 할 수 있습니다. (Contributed by Andrew Svetlov in bpo-32391 [https://bugs.python.org/issue?@action=redirect&bpo=32391].)

새로운 loop.sock_sendfile() 코루틴 메서드는 가능한 경우 os.sendfile 을 사용하여 파일을 전송할 수 있도록 합니다. (Contributed by Andrew Svetlov in bpo-32410 [https://bugs.python.org/issue?@action=redirect&bpo=32410].)

새로운 Future.get_loop() 와 Task.get_loop() 메서드는 태스크 나 퓨처가 만들어진 루프의 인스턴스를 돌려줍니다. Server.get_loop() 는 asyncio.Server 객체에 대해서도 같은 일을 할 수 있도록 합니다. (Contributed by Yury Selivanov in bpo-32415 [https://bugs.python.org/issue?@action=redirect&bpo=32415] and Srinivas Reddy Thatiparthy in bpo-32418 [https://bugs.python.org/issue?@action=redirect&bpo=32418].)

이제 asyncio.Server 의 인스턴스가 어떻게 시작되는지 제어할 수 있습니다. 이전에는 서버를 만들 때 즉시 서버가 시작되었습니다. 새로운 start_serving 키워드 인자는 loop.create_server() 와 loop.create_unix_server() 뿐만 아니라 Server.start_serving() 와 Server.serve_forever() 에도 사용되어 서버 인스턴스를 만드는 것과 시작시키는 것을 분리할 수 있습니다. 새로운 Server.is_serving() 메서드는 서버가 실행 중이면 True 를 돌려줍니다. Server 객체는 이제 비동기 컨텍스트 관리자입니다:

srv = await loop.create_server(...)

async with srv:
    # some code

# At this point, srv is closed and no longer accepts new connections.

(Contributed by Yury Selivanov in bpo-32662 [https://bugs.python.org/issue?@action=redirect&bpo=32662].)

loop.call_later() 가 반환하는 콜백 객체는 예약된 절대 콜백 타임스탬프를 돌려주는 새 when() 메서드를 얻었습니다. (Contributed by Andrew Svetlov in bpo-32741 [https://bugs.python.org/issue?@action=redirect&bpo=32741].)

loop.create_datagram_endpoint() 메서드는 유닉스 소켓 지원을 얻었습니다. (Contributed by Quentin Dawans in bpo-31245 [https://bugs.python.org/issue?@action=redirect&bpo=31245].)

asyncio.open_connection(), asyncio.start_server() 함수, loop.create_connection(), loop.create_server(), loop.create_accepted_socket() 메서드와 해당 유닉스 소켓 변형은 이제 ssl_handshake_timeout 키워드 인자를 받아들입니다. (Contributed by Neil Aspinall in bpo-29970 [https://bugs.python.org/issue?@action=redirect&bpo=29970].)

새로운 Handle.cancelled() 메서드는 콜백이 취소된 경우 True 를 돌려줍니다. (Contributed by Marat Sharafutdinov in bpo-31943 [https://bugs.python.org/issue?@action=redirect&bpo=31943].)

asyncio 소스는 async/await 구문을 사용하도록 변환되었습니다. (Contributed by Andrew Svetlov in bpo-32193 [https://bugs.python.org/issue?@action=redirect&bpo=32193].)

새로운 ReadTransport.is_reading() 메서드를 사용하여 전송계층의 읽기 상태를 판별 할 수 있습니다. 또한 ReadTransport.resume_reading() 과 ReadTransport.pause_reading() 은 이제 멱등적(idempotent)입니다. (Contributed by Yury Selivanov in bpo-32356 [https://bugs.python.org/issue?@action=redirect&bpo=32356].)

소켓 경로를 받아들이는 루프 메서드에는 이제 경로류 객체 를 전달할 수 있습니다. (Contributed by Yury Selivanov in bpo-32066 [https://bugs.python.org/issue?@action=redirect&bpo=32066].)

asyncio 에서 리눅스의 TCP 소켓은 이제 기본적으로 TCP_NODELAY 플래그가 설정된 상태로 만들어집니다. (Contributed by Yury Selivanov and Victor Stinner in bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456].)

취소된 작업에서 발생하는 예외는 더 로깅 되지 않습니다. (Contributed by Yury Selivanov in bpo-30508 [https://bugs.python.org/issue?@action=redirect&bpo=30508].)

새로운 WindowsSelectorEventLoopPolicy 와 WindowsProactorEventLoopPolicy 클래스. (Contributed by Yury Selivanov in bpo-33792 [https://bugs.python.org/issue?@action=redirect&bpo=33792].)

몇몇 asyncio API는 폐지되었습니다.

binascii

b2a_uu() 함수는 선택적 backtick 키워드 인자를 받아들입니다. 참일 때, 0은 스페이스 대신에 '`' 로 표현됩니다. (Contributed by Xiang Zhang in bpo-30103 [https://bugs.python.org/issue?@action=redirect&bpo=30103].)

calendar

HTMLCalendar 클래스는 생성된 HTML 달력에서 CSS 클래스의 개별화를 쉽게 해주는 새로운 클래스 어트리뷰트를 갖습니다. (Contributed by Oz Tiram in bpo-30095 [https://bugs.python.org/issue?@action=redirect&bpo=30095].)

collections

collections.namedtuple() 은 이제 기본값을 지원합니다. (Contributed by Raymond Hettinger in bpo-32320 [https://bugs.python.org/issue?@action=redirect&bpo=32320].)

compileall

compileall.compile_dir() 는 새로운 invalidation_mode 매개 변수를 갖습니다. 이 매개 변수는 해시 기반 .pyc 무효화 를 활성화하는데 사용할 수 있습니다. 무효화 모드는 새로운 --invalidation-mode 인자를 사용하여 명령행에서 지정할 수도 있습니다. (Contributed by Benjamin Peterson in bpo-31650 [https://bugs.python.org/issue?@action=redirect&bpo=31650].)

concurrent.futures

ProcessPoolExecutor 와 ThreadPoolExecutor 는 이제 새로운 initializer 및 initargs 생성자 인자를 지원합니다. (Contributed by Antoine Pitrou in bpo-21423 [https://bugs.python.org/issue?@action=redirect&bpo=21423].)

ProcessPoolExecutor 는 새로운 mp_context 인자를 통해 multiprocessing 컨텍스트를 받아들일 수 있습니다. (Contributed by Thomas Moreau in bpo-31540 [https://bugs.python.org/issue?@action=redirect&bpo=31540].)

contextlib

새로운 nullcontext() 는 ExitStack 보다 더 간단하고 빠른 no-op 컨텍스트 관리자입니다. (Contributed by Jesse-Bakker in bpo-10049 [https://bugs.python.org/issue?@action=redirect&bpo=10049].)

새로운 asynccontextmanager(), AbstractAsyncContextManager, AsyncExitStack 가 추가되어 동기 대응물을 보완합니다. (Contributed by Jelle Zijlstra in bpo-29679 [https://bugs.python.org/issue?@action=redirect&bpo=29679] and bpo-30241 [https://bugs.python.org/issue?@action=redirect&bpo=30241], and by Alexander Mohr and Ilya Kulakov in bpo-29302 [https://bugs.python.org/issue?@action=redirect&bpo=29302].)

cProfile

cProfile 명령행은 이제 스크립트 경로의 대안으로 -m module_name 을 허용합니다. (Contributed by Sanyam Khurana in bpo-21862 [https://bugs.python.org/issue?@action=redirect&bpo=21862].)

crypt

The crypt module now supports the Blowfish hashing method. (Contributed by Serhiy Storchaka in bpo-31664 [https://bugs.python.org/issue?@action=redirect&bpo=31664].)

The mksalt() function now allows specifying the number of rounds for hashing. (Contributed by Serhiy Storchaka in bpo-31702 [https://bugs.python.org/issue?@action=redirect&bpo=31702].)

datetime

새로운 datetime.fromisoformat() 메서드는 datetime.isoformat() 이 출력하는 형식의 문자열로부터 datetime 객체를 생성합니다. (Contributed by Paul Ganssle in bpo-15873 [https://bugs.python.org/issue?@action=redirect&bpo=15873].)

tzinfo 클래스는 이제 분보다 작은 오프셋을 지원합니다. (Contributed by Alexander Belopolsky in bpo-5288 [https://bugs.python.org/issue?@action=redirect&bpo=5288].)

dbm

dbm.dumb 는 이제 읽기 전용 파일 읽기를 지원하며 변경되지 않았을 때 더는 색인 파일을 쓰지 않습니다.

decimal

decimal 모듈은 이제 십진 컨텍스트를 저장하는데 컨텍스트 변수 를 사용한다. (Contributed by Yury Selivanov in bpo-32630 [https://bugs.python.org/issue?@action=redirect&bpo=32630].)

dis

dis() 함수는 이제 중첩된 코드 객체 (컴프리헨션, 제너레이터 표현식 및 중첩된 함수의 코드와 중첩된 클래스를 만드는데 사용되는 코드)를 역 어셈블 할 수 있습니다. 해체 재귀의 최대 깊이는 새로운 * depth * 매개 변수에 의해 제어됩니다. (Contributed by Serhiy Storchaka in bpo-11822 [https://bugs.python.org/issue?@action=redirect&bpo=11822].)

distutils

README.rst 는 이제 distutils 표준 README 목록에 포함됩니다. 그래서 소스 배포판에 포함됩니다. (Contributed by Ryan Gonzalez in bpo-11913 [https://bugs.python.org/issue?@action=redirect&bpo=11913].)

enum

Enum 은 새로운 _ignore_ 클래스 프로퍼티를 얻었는데, 열거형 멤버가 되어서는 안 되는 프로퍼티의 이름들을 나열할 수 있도록 합니다. (Contributed by Ethan Furman in bpo-31801 [https://bugs.python.org/issue?@action=redirect&bpo=31801].)

파이썬 3.8에서 Enum 클래스에서 열거 이외의 객체를 포함 검사하려고 하면 TypeError 가 발생합니다 (예 1 in Color). 마찬가지로 Flag 멤버에서 플래그가 아닌 객체를 포함 검사하려고 하면 TypeError 를 일으킵니다 (예 1 in Perm.RW); 현재는, 두 연산 모두 대신 False 가 반환되며, 폐지되었습니다. (Contributed by Ethan Furman in bpo-33217 [https://bugs.python.org/issue?@action=redirect&bpo=33217].)

functools

functools.singledispatch() 는 이제 형 어노테이션을 사용해서 구현을 등록할 수 있습니다. (Contributed by Łukasz Langa in bpo-32227 [https://bugs.python.org/issue?@action=redirect&bpo=32227].)

gc

새로운 gc.freeze() 함수는 가비지 수집기가 추적 한 모든 객체를 고정하고 미래의 수집에서 그것들을 제외합니다. POSIX fork() 호출 전에 사용하면 GC를 쓰기 전에 복사(copy-on-write) 친화적으로 만들고 수집 속도를 높일 수 있습니다. 새로운 gc.unfreeze() 함수는 이 작업을 되돌립니다. 또한, gc.get_freeze_count()를 사용하여 고정된 객체의 수를 얻을 수 있습니다. (Contributed by Li Zekun in bpo-31558 [https://bugs.python.org/issue?@action=redirect&bpo=31558].)

hmac

hmac 모듈은 이제 최적화된 단일 호출 digest() 함수를 제공합니다. HMAC() 보다 최대 3배 빠릅니다. (Contributed by Christian Heimes in bpo-32433 [https://bugs.python.org/issue?@action=redirect&bpo=32433].)

http.client

HTTPConnection 과 HTTPSConnection 은 이제 향상된 업로드 처리량을 위해 새로운 blocksize 인자를 지원합니다. (Contributed by Nir Soffer in bpo-31945 [https://bugs.python.org/issue?@action=redirect&bpo=31945].)

http.server

SimpleHTTPRequestHandler 는 이제 HTTP If-Modified-Since 헤더를 지원합니다. 헤더에 지정된 시간 이후에 대상 파일이 수정되지 않았으면 서버는 304 응답 상태를 돌려줍니다. (Contributed by Pierre Quentel in bpo-29654 [https://bugs.python.org/issue?@action=redirect&bpo=29654].)

SimpleHTTPRequestHandler 는 새로운 --directory 명령행 인자와 더불어 새로운 directory 인자를 받아들입니다. 이 매개 변수를 사용하면 서버는 지정된 디렉터리를 제공하는데, 기본적으로는 현재 작업 디렉터리를 사용합니다. (Contributed by Stéphane Wirtel and Julien Palard in bpo-28707 [https://bugs.python.org/issue?@action=redirect&bpo=28707].)

새로운 ThreadingHTTPServer 클래스는 ThreadingMixin 을 사용하여 요청을 처리하는 데 스레드를 사용합니다. http.server 가 -m 로 실행될 때 사용됩니다. (Contributed by Julien Palard in bpo-31639 [https://bugs.python.org/issue?@action=redirect&bpo=31639].)

idlelib 및 IDLE

자동 완성을 위한 여러 수정. (Contributed by Louie Lu in bpo-15786 [https://bugs.python.org/issue?@action=redirect&bpo=15786].)

Module Browser (File 메뉴에 있는데, 예전에는 Class Browser라고 불렸습니다)는 이제 최상위 함수와 클래스 외에도 중첩된 함수와 클래스도 표시합니다. (Contributed by Guilherme Polo, Cheryl Sabella, and Terry Jan Reedy in bpo-1612262 [https://bugs.python.org/issue?@action=redirect&bpo=1612262].)

설정 대화 상자(Options, Configure IDLE)는 모양과 기능을 향상하기 위해 부분적으로 다시 작성되었습니다. (Contributed by Cheryl Sabella and Terry Jan Reedy in multiple issues.)

이제 글꼴 표본에 라틴 문자 이외의 문자가 포함되어 사용자가 특정 글꼴을 선택했을 때의 효과를 더 잘 볼 수 있습니다. (Contributed by Terry Jan Reedy in bpo-13802 [https://bugs.python.org/issue?@action=redirect&bpo=13802].) 표본을 편집하여 다른 문자를 포함할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-31860 [https://bugs.python.org/issue?@action=redirect&bpo=31860].)

이전에는 확장 기능으로 구현된 IDLE 기능이 일반 기능으로 다시 구현되었습니다. 이것들의 설정을 Extensions 탭에서 다른 대화 상자 탭으로 옮겼습니다. (Contributed by Charles Wohlganger and Terry Jan Reedy in bpo-27099 [https://bugs.python.org/issue?@action=redirect&bpo=27099].)

편집기 코드 컨텍스트 옵션이 개정되었습니다. 상자는 최대 행 수까지 모든 컨텍스트 행을 표시합니다. 컨텍스트 행을 클릭하면 편집기가 해당 행으로 이동합니다. 사용자 정의 테마의 컨텍스트 색상이 설정 대화 상자의 강조 표시 탭에 추가되었습니다. (Contributed by Cheryl Sabella and Terry Jan Reedy in bpo-33642 [https://bugs.python.org/issue?@action=redirect&bpo=33642], bpo-33768 [https://bugs.python.org/issue?@action=redirect&bpo=33768], and bpo-33679 [https://bugs.python.org/issue?@action=redirect&bpo=33679].)

윈도우에서, 새로운 API 호출이 tk가 DPI에 맞게 조정된다는 것을 윈도우에 알려줍니다. Windows 8.1+ 또는 10에서, 파이썬 바이너리의 DPI 호환성 속성을 변경하지 않고도, 96DPI보다 큰 모니터 해상도를 사용하면, 텍스트와 선이 더 선명해집니다. 그렇지 않으면 아무런 효과도 일으키지 않습니다. (Contributed by Terry Jan Reedy in bpo-33656 [https://bugs.python.org/issue?@action=redirect&bpo=33656].)

3.7.1의 새로운 기능:

N 줄(기본값은 50)을 초과하는 출력은 버튼으로 축소됩니다. N은 설정 대화 상자의 General 페이지의 PyShell 섹션에서 변경할 수 있습니다. 저 작은, 하지만 아주 길 수도 있는, 줄은 출력을 마우스 오른쪽 버튼으로 클릭하면 축소할 수 있습니다. 축소된 출력은 버튼을 더블 클릭해서 재자리에서 확대하거나, 버튼을 마우스 오른쪽 단추로 클릭하여 클립 보드나 별도의 창으로 확대할 수 있습니다. (Contributed by Tal Einat in bpo-1529353 [https://bugs.python.org/issue?@action=redirect&bpo=1529353].).

위의 변경 사항은 3.6 유지 보수 배포로 역 이식되었습니다.

3.7.4의 새로운 기능:

사용자 정의 설정으로 모듈을 실행하기 위해 Run 메뉴에 “Run Customized”를 추가합니다. 입력한 모든 명령 줄 인자는 sys.argv에 추가됩니다. 다음 사용자 정의 실행을 위해 상자에 다시 나타납니다. 일반적인 셸 메인 모듈 재시작을 억제할 수도 있습니다. (Contributed by Cheryl Sabella, Terry Jan Reedy, and others in bpo-5680 [https://bugs.python.org/issue?@action=redirect&bpo=5680] and bpo-37627 [https://bugs.python.org/issue?@action=redirect&bpo=37627].)

3.7.5의 새로운 기능:

IDLE 편집기 창에 선택적인 줄 번호를 추가합니다. 창은 구성 대화 상자의 General 탭에서 설정하지 않는 한 줄 번호 없이 열립니다. 기존 창의 줄 번호는 옵션 메뉴에서 표시되거나 숨겨집니다. (Contributed by Tal Einat and Saimadhav Heblikar in bpo-17535 [https://bugs.python.org/issue?@action=redirect&bpo=17535].)

importlib

importlib.abc.ResourceReader ABC가 도입되어 패키지에서 리소스를 로딩하는 것을 지원합니다. importlib.resources 를 참조하세요. (Contributed by Barry Warsaw, Brett Cannon in bpo-32248 [https://bugs.python.org/issue?@action=redirect&bpo=32248].)

importlib.reload() 는 이제 모듈에 스펙이 없는 경우 ModuleNotFoundError 를 발생시킵니다. (Contributed by Garvit Khatri in bpo-29851 [https://bugs.python.org/issue?@action=redirect&bpo=29851].)

importlib.find_spec()은 이제 지정된 부모 모듈이 패키지가 아닌 경우 (즉 __path__ 어트리뷰트가 없는 경우) AttributeError 대신에 ModuleNotFoundError 를 발생시킵니다. (Contributed by Milan Oberkirch in bpo-30436 [https://bugs.python.org/issue?@action=redirect&bpo=30436].)

새로운 importlib.source_hash() 는 전달 된 소스의 해시를 계산하는 데 사용될 수 있습니다. 해시 기반 .pyc 파일 은 함수가 반환하는 값을 포함합니다.

io

새로운 TextIOWrapper.reconfigure() 메서드를 사용하여 텍스트 스트림을 새로운 설정으로 재구성 할 수 있습니다. (Contributed by Antoine Pitrou in bpo-30526 [https://bugs.python.org/issue?@action=redirect&bpo=30526] and INADA Naoki in bpo-15216 [https://bugs.python.org/issue?@action=redirect&bpo=15216].)

ipaddress

ipaddress.IPv6Network 와 ipaddress.IPv4Network 의 새로운 subnet_of() 와 supernet_of() 메서드는 네트워크 포함 테스트에 사용될 수 있습니다. (Contributed by Michel Albert and Cheryl Sabella in bpo-20825 [https://bugs.python.org/issue?@action=redirect&bpo=20825].)

itertools

itertools.islice() 는 start, stop, step 인자로 정수류 객체 를 받아들입니다. (Contributed by Will Roberts in bpo-30537 [https://bugs.python.org/issue?@action=redirect&bpo=30537].)

locale

locale.format_string() 의 새로운 monetary 인자는 변환에 화폐 천 단위 분리자 및 그룹화 문자열을 사용하도록 만듭니다. (Contributed by Garvit in bpo-10379 [https://bugs.python.org/issue?@action=redirect&bpo=10379].)

locale.getpreferredencoding() 함수는 이제 안드로이드나 강제 UTF-8 모드 일 때 항상 'UTF-8' 을 반환합니다.

logging

Logger 인스턴스는 이제 피클(pickle) 할 수 있습니다. (Contributed by Vinay Sajip in bpo-30520 [https://bugs.python.org/issue?@action=redirect&bpo=30520].)

새로운 StreamHandler.setStream() 메서드는 처리기 생성 후 로거 스트림을 대체하는 데 사용될 수 있습니다. (Contributed by Vinay Sajip in bpo-30522 [https://bugs.python.org/issue?@action=redirect&bpo=30522].)

이제 logging.config.fileConfig() 에 전달된 구성에서 처리기 생성자에 대한 키워드 인자를 지정할 수 있습니다. (Contributed by Preston Landers in bpo-31080 [https://bugs.python.org/issue?@action=redirect&bpo=31080].)

math

새로운 math.remainder() 함수는 IEEE 754 스타일의 나머지 연산을 구현합니다. (Contributed by Mark Dickinson in bpo-29962 [https://bugs.python.org/issue?@action=redirect&bpo=29962].)

mimetypes

.bmp의 MIME 형이 'image/x-ms-bmp' 에서 'image/bmp' 로 변경되었습니다. (Contributed by Nitish Chandra in bpo-22589 [https://bugs.python.org/issue?@action=redirect&bpo=22589].)

msilib

The new Database.Close() method can be used to close the MSI database. (Contributed by Berker Peksag in bpo-20486 [https://bugs.python.org/issue?@action=redirect&bpo=20486].)

multiprocessing

새로운 Process.close() 메서드는 명시적으로 프로세스 객체를 닫고 그와 연관된 모든 자원을 해제합니다. 하부 프로세스가 여전히 실행 중이면 ValueError 를 일으킵니다. (Contributed by Antoine Pitrou in bpo-30596 [https://bugs.python.org/issue?@action=redirect&bpo=30596].)

새로운 Process.kill() 메서드는 유닉스에서 SIGKILL 시그널을 사용하여 프로세스를 종료시키는데 사용될 수 있습니다. (Contributed by Vitor Pereira in bpo-30794 [https://bugs.python.org/issue?@action=redirect&bpo=30794].)

Process 에 의해 생성된 데몬이 아닌 스레드는 이제 프로세스 종료 시에 조인(join)됩니다. (Contributed by Antoine Pitrou in bpo-18966 [https://bugs.python.org/issue?@action=redirect&bpo=18966].)

os

os.fwalk() 는 이제 경로 인자로 bytes 도 받아들입니다. (Contributed by Serhiy Storchaka in bpo-28682 [https://bugs.python.org/issue?@action=redirect&bpo=28682].)

os.scandir() 은 파일 기술자 에 대한 지원을 얻었습니다. (Contributed by Serhiy Storchaka in bpo-25996 [https://bugs.python.org/issue?@action=redirect&bpo=25996].)

새로운 register_at_fork() 함수는 프로세스 포크 때 실행될 파이썬 콜백을 등록 할 수 있게 합니다. (Contributed by Antoine Pitrou in bpo-16500 [https://bugs.python.org/issue?@action=redirect&bpo=16500].)

os.preadv() (os.readv() 와 os.pread() 의 기능을 결합한 것)와 os.pwritev() 함수 (os.writev() 와 os.pwrite() 의 기능을 결합한 것)를 추가했습니다. (Contributed by Pablo Galindo in bpo-31368 [https://bugs.python.org/issue?@action=redirect&bpo=31368].)

The mode argument of os.makedirs() no longer affects the file permission bits of newly created intermediate-level directories. (Contributed by Serhiy Storchaka in bpo-19930 [https://bugs.python.org/issue?@action=redirect&bpo=19930].)

os.dup2() 는 이제 새로운 파일 기술자를 반환합니다. 이전에는 항상 None 을 반환했습니다. (Contributed by Benjamin Peterson in bpo-32441 [https://bugs.python.org/issue?@action=redirect&bpo=32441].)

os.stat() 에 의해 반환된 구조체는 이제 솔라리스와 그 파생물에서 st_fstype 어트리뷰트를 포함합니다. (Contributed by Jesús Cea Avión in bpo-32659 [https://bugs.python.org/issue?@action=redirect&bpo=32659].)

pathlib

새로운 Path.is_mount() 메서드는 이제 POSIX 시스템에서 사용할 수 있으며 경로가 마운트 지점인지 아닌지를 결정하는 데 사용할 수 있습니다. (Contributed by Cooper Ry Lees in bpo-30897 [https://bugs.python.org/issue?@action=redirect&bpo=30897].)

pdb

pdb.set_trace() 는 이제 선택적 header 키워드 전용 인자를 취합니다. 주어진 경우, 디버깅이 시작되기 바로 전에 콘솔에 출력됩니다. (Contributed by Barry Warsaw in bpo-31389 [https://bugs.python.org/issue?@action=redirect&bpo=31389].)

pdb 명령행은 이제 스크립트 파일의 대안으로 -m module_name 을 받아들입니다. (Contributed by Mario Corchero in bpo-32206 [https://bugs.python.org/issue?@action=redirect&bpo=32206].)

py_compile

py_compile.compile() 은 – 그리고 자연히 compileall 도 – 이제 SOURCE_DATE_EPOCH 환경 변수가 설정되면 해시 기반 유효성 검사를 위해 .pyc 파일을 무조건 생성합니다. 이것은 .pyc 파일의 재현 가능한 빌드 [https://reproducible-builds.org/] 를 보장할 수 있도록 한다. (Contributed by Bernhard M. Wiedemann in bpo-29708 [https://bugs.python.org/issue?@action=redirect&bpo=29708].)

pydoc

pydoc 서버는 이제 새로운 -n 명령행 인자로 지정된 임의의 호스트 이름에 바인드 할 수 있습니다. (Contributed by Feanil Patel in bpo-31128 [https://bugs.python.org/issue?@action=redirect&bpo=31128].)

queue

새로운 SimpleQueue 클래스는 무제한 FIFO 큐입니다. (Contributed by Antoine Pitrou in bpo-14976 [https://bugs.python.org/issue?@action=redirect&bpo=14976].)

re

플래그 re.ASCII, re.LOCALE 및 re.UNICODE 를 그룹의 스코프 내에서 설정할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-31690 [https://bugs.python.org/issue?@action=redirect&bpo=31690].)

re.split() 는 이제 빈 문자열과 일치하는 r'\b', '^$' 또는 (?=-) 와 같은 패턴으로 나누는 것을 지원합니다. (Contributed by Serhiy Storchaka in bpo-25054 [https://bugs.python.org/issue?@action=redirect&bpo=25054].)

re.LOCALE 플래그로 컴파일된 정규식은 더는 컴파일 시간의 로케일에 의존하지 않습니다. 로케일 설정은 컴파일된 정규식이 사용될 때 적용됩니다. (Contributed by Serhiy Storchaka in bpo-30215 [https://bugs.python.org/issue?@action=redirect&bpo=30215].)

정규식이 앞으로 의미적인 변경이 있을 문자 집합 구조물(가령 중첩된 집합과 집합 연산)을 포함하면 이제 FutureWarning 을 줍니다. (Contributed by Serhiy Storchaka in bpo-30349 [https://bugs.python.org/issue?@action=redirect&bpo=30349].)

copy.copy() 와 copy.deepcopy() 를 사용하여 컴파일된 정규식과 매치 객체를 복사 할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-10076 [https://bugs.python.org/issue?@action=redirect&bpo=10076].)

signal

signal.set_wakeup_fd() 함수의 새로운 warn_on_full_buffer 인자는 웨이크업 버퍼 오버플로가 발생했을 때 파이썬이 표준 에러로 경고를 출력할지를 지정할 수 있게 합니다. (Contributed by Nathaniel J. Smith in bpo-30050 [https://bugs.python.org/issue?@action=redirect&bpo=30050].)

socket

새로운 socket.getblocking() 메서드는 소켓이 블로킹 모드에 있으면 True 를 반환하고, 그렇지 않으면 False 를 반환합니다. (Contributed by Yury Selivanov in bpo-32373 [https://bugs.python.org/issue?@action=redirect&bpo=32373].)

새로운 socket.close() 함수는 전달된 소켓 파일 기술자를 닫습니다. 이 함수는 플랫폼 간 호환성을 높이기 위해 os.close() 대신 사용되어야 합니다. (Contributed by Christian Heimes in bpo-32454 [https://bugs.python.org/issue?@action=redirect&bpo=32454].)

The socket module now exposes the socket.TCP_CONGESTION (Linux 2.6.13), socket.TCP_USER_TIMEOUT (Linux 2.6.37), and socket.TCP_NOTSENT_LOWAT (Linux 3.12) constants. (Contributed by Omar Sandoval in bpo-26273 [https://bugs.python.org/issue?@action=redirect&bpo=26273] and Nathaniel J. Smith in bpo-29728 [https://bugs.python.org/issue?@action=redirect&bpo=29728].)

Support for socket.AF_VSOCK sockets has been added to allow communication between virtual machines and their hosts. (Contributed by Cathy Avery in bpo-27584 [https://bugs.python.org/issue?@action=redirect&bpo=27584].)

소켓은 이제 기본적으로 파일 기술자에서 패밀리, 형 및 프로토콜을 자동 감지합니다. (Contributed by Christian Heimes in bpo-28134 [https://bugs.python.org/issue?@action=redirect&bpo=28134].)

socketserver

socketserver.ThreadingMixIn.server_close() 는 이제 모든 데몬이 아닌 스레드가 완료될 때까지 대기합니다. socketserver.ForkingMixIn.server_close() 는 모든 자식 프로세스가 완료될 때까지 대기합니다.

새로운 socketserver.ForkingMixIn.block_on_close 클래스 어트리뷰트를 socketserver.ForkingMixIn 과 socketserver.ThreadingMixIn 클래스에 추가했습니다. 3.7 이전의 동작을 얻으려면 클래스 어트리뷰트를 False 로 설정하십시오.

sqlite3

sqlite3.Connection 은 이제 하부 SQLite 라이브러리의 버전이 3.6.11 이상일 때 backup() 메서드를 노출합니다. (Contributed by Lele Gaifax in bpo-27645 [https://bugs.python.org/issue?@action=redirect&bpo=27645].)

sqlite3.connect() 의 database 인자는 이제 문자열뿐만 아니라 모든 경로류 객체 를 받아들입니다. (Contributed by Anders Lorentsen in bpo-31843 [https://bugs.python.org/issue?@action=redirect&bpo=31843].)

ssl

ssl 모듈은 이제 match_hostname() 대신 OpenSSL의 내장 API를 사용하여 호스트 이름이나 IP 주소를 확인합니다. 값은 TLS 핸드 셰이크 중에 유효성이 검사됩니다. 호스트 이름 검사 실패와 같은 인증서 유효성 검사 오류가 발생하면 이제 SSLCertVerificationError 가 발생하고 적절한 TLS 경고 메시지와 함께 핸드 셰이크가 중단됩니다. 새 예외에는 추가 정보가 들어 있습니다. 호스트 이름 유효성 검증은 SSLContext.hostname_checks_common_name 을 사용하여 사용자 정의 할 수 있습니다. (Contributed by Christian Heimes in bpo-31399 [https://bugs.python.org/issue?@action=redirect&bpo=31399].)

참고

향상된 호스트 이름 검사에는 OpenSSL 1.0.2 또는 1.1과 호환되는 libssl 구현이 필요합니다. 따라서, OpenSSL 0.9.8 및 1.0.1은 더는 지원되지 않습니다 (더 자세한 내용은 플랫폼 지원 제거를 보세요). ssl 모듈은 대부분 LibreSSL 2.7.2 이상과 호환됩니다.

ssl 모듈은 더는 SNI TLS 확장에서 IP 주소를 전송하지 않습니다. (Contributed by Christian Heimes in bpo-32185 [https://bugs.python.org/issue?@action=redirect&bpo=32185].)

match_hostname()은 www*.example.org 와 같은 부분적인 와일드카드를 더는 지원하지 않습니다. (Contributed by Mandeep Singh in bpo-23033 [https://bugs.python.org/issue?@action=redirect&bpo=23033] and Christian Heimes in bpo-31399 [https://bugs.python.org/issue?@action=redirect&bpo=31399].)

ssl 모듈의 기본 사이퍼 군 선택은 이제 하드 코딩된 화이트리스트가 아닌 블랙리스트 접근법을 사용합니다. 파이썬은 더는 OpenSSL 보안 업데이트 때문에 차단된 사이퍼를 다시 활성화하지 않습니다. 기본 사이퍼 군 선택은 컴파일 시점에 구성 할 수 있습니다. (Contributed by Christian Heimes in bpo-31429 [https://bugs.python.org/issue?@action=redirect&bpo=31429].)

국제화된 도메인 이름 (IDN)을 포함하는 서버 인증서의 유효성 검사가 이제 지원됩니다. 이 변경의 일부로, SSLSocket.server_hostname 어트리뷰트는 이제 U-label 형식("pythön.org")보다는 A-label 형식("xn--pythn-mua.org")으로 기대하는 호스트 이름을 저장합니다. (Contributed by Nathaniel J. Smith and Christian Heimes in bpo-28414 [https://bugs.python.org/issue?@action=redirect&bpo=28414].)

ssl 모듈은 TLS 1.3과 OpenSSL 1.1.1을 예비적이고 실험적으로 지원합니다. 파이썬 3.7.0 배포 당시, OpenSSL 1.1.1은 아직 개발 중이며 TLS 1.3은 아직 완성되지 않았습니다. TLS 1.3 핸드 셰이크와 프로토콜은 TLS 1.2 및 그 이전 버전과 약간 다르게 동작합니다. TLS 1.3을 참조하세요. (Contributed by Christian Heimes in bpo-32947 [https://bugs.python.org/issue?@action=redirect&bpo=32947], bpo-20995 [https://bugs.python.org/issue?@action=redirect&bpo=20995], bpo-29136 [https://bugs.python.org/issue?@action=redirect&bpo=29136], bpo-30622 [https://bugs.python.org/issue?@action=redirect&bpo=30622] and bpo-33618 [https://bugs.python.org/issue?@action=redirect&bpo=33618])

SSLSocket 과 SSLObject 는 더는 공개 생성자를 가지고 있지 않습니다. 직접 인스턴스를 만드는 것은 결코 문서로 만들어지고 지원되는 기능이 아닙니다. 인스턴스는 SSLContext 메서드 wrap_socket()과 wrap_bio()로 생성되어야 합니다. (Contributed by Christian Heimes in bpo-32951 [https://bugs.python.org/issue?@action=redirect&bpo=32951])

최소 및 최대 TLS 프로토콜 버전을 설정하기 위한 OpenSSL 1.1 API는 SSLContext.minimum_version 과 SSLContext.maximum_version 로 제공됩니다. 지원되는 프로토콜은 여러 가지 새 플래그로 표시됩니다, 가령 HAS_TLSv1_1. (Contributed by Christian Heimes in bpo-32609 [https://bugs.python.org/issue?@action=redirect&bpo=32609].)

Added ssl.SSLContext.post_handshake_auth to enable and ssl.SSLSocket.verify_client_post_handshake() to initiate TLS 1.3 post-handshake authentication. (Contributed by Christian Heimes in gh-78851 [https://github.com/python/cpython/issues/78851].)

string

string.Template 은 이제 중괄호로 둘러싼 치환식과 그렇지 않은 치환식의 정규식을 따로 선택적으로 수정할 수 있도록 합니다. (Contributed by Barry Warsaw in bpo-1198569 [https://bugs.python.org/issue?@action=redirect&bpo=1198569].)

subprocess

The subprocess.run() function accepts the new capture_output keyword argument. When true, stdout and stderr will be captured. This is equivalent to passing subprocess.PIPE as stdout and stderr arguments. (Contributed by Bo Bayles in bpo-32102 [https://bugs.python.org/issue?@action=redirect&bpo=32102].)

subprocess.run 함수와 subprocess.Popen 생성자는 이제 text 키워드 인자를 universal_newlines 의 별칭으로 받아들입니다. (Contributed by Andrew Clegg in bpo-31756 [https://bugs.python.org/issue?@action=redirect&bpo=31756].)

윈도우에서 close_fds 의 기본값은 표준 핸들을 리디렉션 할 때 False 에서 True 로 변경되었습니다. 이제 표준 핸들을 리디렉션 할 때 close_fds 를 참으로 설정할 수 있습니다. subprocess.Popen 을 참조하세요. 이것은 지원되는 모든 플랫폼에서 이제 close_fds 의 기본값이 True 임을 뜻합니다. (Contributed by Segev Finer in bpo-19764 [https://bugs.python.org/issue?@action=redirect&bpo=19764].)

subprocess 모듈은 이제 subprocess.call(), subprocess.run() 중에, 또는 Popen 컨텍스트 관리자에 있는 동안 KeyboardInterrupt 를 더 우아하게 처리합니다. 이제 KeyboardInterrupt 예외 처리를 계속하기 전에 자식이 종료될 때까지 약간의 시간을 기다립니다. (Contributed by Gregory P. Smith in bpo-25942 [https://bugs.python.org/issue?@action=redirect&bpo=25942].)

sys

새로운 sys.breakpointhook() 훅 함수는 내장 breakpoint() 에 의해 호출됩니다. (Contributed by Barry Warsaw in bpo-31353 [https://bugs.python.org/issue?@action=redirect&bpo=31353].)

안드로이드에서, 새로운 sys.getandroidapilevel() 은 빌드 시간 안드로이드 API 버전을 반환합니다. (Contributed by Victor Stinner in bpo-28740 [https://bugs.python.org/issue?@action=redirect&bpo=28740].)

새로운 sys.get_coroutine_origin_tracking_depth() 함수는 새로운 sys.set_coroutine_origin_tracking_depth() 에 의해 설정된 현재 코루틴 원점 추적 깊이를 반환합니다. asyncio 가 폐지된 sys.set_coroutine_wrapper() 대신 이 새로운 API를 사용하도록 변환되었습니다. (Contributed by Nathaniel J. Smith in bpo-32591 [https://bugs.python.org/issue?@action=redirect&bpo=32591].)

time

PEP 564 [https://peps.python.org/pep-0564/] 는 time 모듈에 나노초 해상도의 새로운 함수 6개를 추가합니다:

time.clock_gettime_ns()

time.clock_settime_ns()

time.monotonic_ns()

time.perf_counter_ns()

time.process_time_ns()

time.time_ns()

새로운 시계 식별자가 추가되었습니다:

time.CLOCK_BOOTTIME (Linux): Identical to time.CLOCK_MONOTONIC, except it also includes any time that the system is suspended.

time.CLOCK_PROF (FreeBSD, NetBSD and OpenBSD): High-resolution per-process CPU timer.

time.CLOCK_UPTIME (FreeBSD, OpenBSD): Time whose absolute value is the time the system has been running and not suspended, providing accurate uptime measurement.

새로운 time.thread_time()과 time.thread_time_ns() 함수는 스레드 당 CPU 시간을 측정하는 데 사용될 수 있습니다. (Contributed by Antoine Pitrou in bpo-32025 [https://bugs.python.org/issue?@action=redirect&bpo=32025].)

새로운 time.pthread_getcpuclockid() 함수는 스레드 별 CPU 시간 시계의 시계 ID를 반환합니다.

tkinter

이제 새로운 tkinter.ttk.Spinbox 클래스를 사용할 수 있습니다. (Contributed by Alan Moore in bpo-32585 [https://bugs.python.org/issue?@action=redirect&bpo=32585].)

tracemalloc

tracemalloc.Traceback 은 더 일반 트레이스백과 같이 동작하여, 프레임을 가장 오래된 것부터 가장 최근의 것으로 정렬합니다. Traceback.format() 은 이제 음의 limit 을 받아들이고, 결과를 abs(limit) 개의 가장 오래된 프레임으로 잘라냅니다. 이전 동작을 얻으려면, Traceback.format() 에 새로운 most_recent_first 인자를 사용하십시오. (Contributed by Jesse Bakker in bpo-32121 [https://bugs.python.org/issue?@action=redirect&bpo=32121].)

types

이제 새로운 WrapperDescriptorType, MethodWrapperType, MethodDescriptorType, ClassMethodDescriptorType 클래스를 사용할 수 있습니다. (Contributed by Manuel Krebber and Guido van Rossum in bpo-29377 [https://bugs.python.org/issue?@action=redirect&bpo=29377], and Serhiy Storchaka in bpo-32265 [https://bugs.python.org/issue?@action=redirect&bpo=32265].)

새로운 types.resolve_bases() 함수는 PEP 560 [https://peps.python.org/pep-0560/] 에 지정된 대로 MRO 항목을 동적으로 결정합니다. (Contributed by Ivan Levkivskyi in bpo-32717 [https://bugs.python.org/issue?@action=redirect&bpo=32717].)

unicodedata

The internal unicodedata database has been upgraded to use Unicode 11 [https://www.unicode.org/versions/Unicode11.0.0/]. (Contributed by Benjamin Peterson.)

unittest

새로운 -k 명령행 옵션은 이름 부분 문자열이나 유닉스 셸과 같은 패턴으로 테스트를 필터링 할 수 있습니다. 예를 들어 python -m unittest -k foo 는 foo_tests.SomeTest.test_something, bar_tests.SomeTest.test_foo 를 실행하지만, bar_tests.FooTest.test_something 는 실행하지 않습니다. (Contributed by Jonas Haag in bpo-32071 [https://bugs.python.org/issue?@action=redirect&bpo=32071].)

unittest.mock

sentinel 어트리뷰트는 이제 복사되거나 피클될 때 그들의 아이덴티티를 보존합니다. (Contributed by Serhiy Storchaka in bpo-20804 [https://bugs.python.org/issue?@action=redirect&bpo=20804].)

새로운 seal() 함수는 Mock 인스턴스를 봉인하도록 허용합니다. 추가적인 어트리뷰트 모의 객체를 만들 수 없도록 합니다. 봉인은 모의 객체인 모든 어트리뷰트에 재귀적으로 적용됩니다. (Contributed by Mario Corchero in bpo-30541 [https://bugs.python.org/issue?@action=redirect&bpo=30541].)

urllib.parse

urllib.parse.quote() 가 RFC 2396 [https://datatracker.ietf.org/doc/html/rfc2396.html]에서 RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]으로 갱신되어, 기본적으로 이스케이프 되지 않는 문자 집합에 ~ 가 추가되었습니다. (Contributed by Christian Theune and Ratnadeep Debnath in bpo-16285 [https://bugs.python.org/issue?@action=redirect&bpo=16285].)

uu

The uu.encode() function now accepts an optional backtick keyword argument. When it’s true, zeros are represented by '`' instead of spaces. (Contributed by Xiang Zhang in bpo-30103 [https://bugs.python.org/issue?@action=redirect&bpo=30103].)

uuid

새로운 UUID.is_safe 어트리뷰트는 생성된 UUID가 다중 프로세스에 안전한 방법으로 생성되었는지에 대해 플랫폼이 주는 정보를 전달합니다. (Contributed by Barry Warsaw in bpo-22807 [https://bugs.python.org/issue?@action=redirect&bpo=22807].)

uuid.getnode() 는 이제 지역적으로 관리되는 MAC 주소보다 보편적으로 관리되는 MAC 주소를 선호합니다. 이것은 uuid.uuid1() 에서 반환된 UUID의 글로벌 유일성을 더 잘 보장합니다. 지역적으로 관리되는 MAC 주소 만 사용할 수 있는 경우, 처음 발견된 MAC 주소가 반환됩니다. (Contributed by Barry Warsaw in bpo-32107 [https://bugs.python.org/issue?@action=redirect&bpo=32107].)

warnings

기본 경고 필터의 초기화가 다음과 같이 변경되었습니다:

명령행 옵션(-b 및 새로운 CPython 특정 -X dev 옵션을 포함합니다)을 통해 활성화된 경고는 항상 sys.warnoptions 어트리뷰트를 통해 경고 절차로 전달됩니다.

명령행 또는 환경을 통해 활성화된 경고 필터의 우선순위는 다음과 같습니다:

-b (또는 -bb)에 의한 BytesWarning 필터

-W 옵션으로 지정된 모든 필터

PYTHONWARNINGS 환경 변수로 지정된 모든 필터

다른 모든 CPython 특정 필터 (예, 새로운 -X dev 모드를 위해 추가된 default 필터)

경고 절차에 의해 직접 정의된 모든 묵시적 필터

in CPython debug builds, all warnings are now displayed by default (the implicit filter list is empty)

(Contributed by Nick Coghlan and Victor Stinner in bpo-20361 [https://bugs.python.org/issue?@action=redirect&bpo=20361], bpo-32043 [https://bugs.python.org/issue?@action=redirect&bpo=32043], and bpo-32230 [https://bugs.python.org/issue?@action=redirect&bpo=32230].)

폐지 경고는 단일 파일 스크립트 및 대화식 프롬프트에서 다시 한번 기본적으로 표시됩니다. 자세한 내용은 PEP 565: __main__ 의 DeprecationWarning 표시 를 참조하십시오. (Contributed by Nick Coghlan in bpo-31975 [https://bugs.python.org/issue?@action=redirect&bpo=31975].)

xml

As mitigation against DTD and external entity retrieval, the xml.dom.minidom and xml.sax modules no longer process external entities by default. (Contributed by Christian Heimes in gh-61441 [https://github.com/python/cpython/issues/61441].)

xml.etree

find() 의 ElementPath 서술자는 이제 [. = "text"] 로 자식의 텍스트뿐만 아니라 현재 노드의 텍스트를 비교할 수 있습니다. 서술자는 가독성을 높이기 위해 스페이스를 추가할 수도 있습니다. (Contributed by Stefan Behnel in bpo-31648 [https://bugs.python.org/issue?@action=redirect&bpo=31648].)

xmlrpc.server

SimpleXMLRPCDispatcher.register_function 는 이제 데코레이터로 사용할 수 있습니다. (Contributed by Xiang Zhang in bpo-7769 [https://bugs.python.org/issue?@action=redirect&bpo=7769].)

zipapp

함수 create_archive() 는 이제 사용자가 저장소에 포함되어야 하는 파일을 선택할 수 있도록 선택적 filter 인자를 받아들입니다. (Contributed by Irmen de Jong in bpo-31072 [https://bugs.python.org/issue?@action=redirect&bpo=31072].)

함수 create_archive() 는 이제 압축된 저장소를 생성하기 위해 선택적 compressed 인자를 받아들입니다. 명령행 옵션 --compress 도 압축을 지원하기 위해 추가되었습니다. (Contributed by Zhiming Wang in bpo-31638 [https://bugs.python.org/issue?@action=redirect&bpo=31638].)

zipfile

ZipFile 은 이제 압축 수준을 제어하기 위해 새로운 compresslevel 매개변수를 받아들입니다. (Contributed by Bo Bayles in bpo-21417 [https://bugs.python.org/issue?@action=redirect&bpo=21417].)

ZipFile 에 의해 생성된 저장소에 있는 서브 디렉터리는 이제 알파벳순으로 저장됩니다. (Contributed by Bernhard M. Wiedemann in bpo-30693 [https://bugs.python.org/issue?@action=redirect&bpo=30693].)

C API 변경

스레드-로컬 저장소를 위한 새로운 API가 구현되었습니다. 개요는 PEP 539: 스레드-로컬 저장소를 위한 새로운 C API 를, 완전한 레퍼런스는 스레드별 저장소 (TSS - Thread Specific Storage) API를 보십시오. (Contributed by Masayuki Yamamoto in bpo-25658 [https://bugs.python.org/issue?@action=redirect&bpo=25658].)

새로운 컨텍스트 변수 기능은 다수의 새로운 C API를 노출합니다.

새로운 PyImport_GetModule() 함수는 주어진 이름으로 이전에 임포트 한 모듈을 반환합니다. (Contributed by Eric Snow in bpo-28411 [https://bugs.python.org/issue?@action=redirect&bpo=28411].)

새로운 Py_RETURN_RICHCOMPARE 매크로는 풍부한 비교 함수를 작성하기 쉽게 합니다. (Contributed by Petr Victorin in bpo-23699 [https://bugs.python.org/issue?@action=redirect&bpo=23699].)

새로운 Py_UNREACHABLE 매크로는 도달할 수 없는 코드 경로를 표시하는 데 사용될 수 있습니다. (Contributed by Barry Warsaw in bpo-31338 [https://bugs.python.org/issue?@action=redirect&bpo=31338].)

tracemalloc 은 이제 새로운 PyTraceMalloc_Track()과 PyTraceMalloc_Untrack() 함수를 통해 C API를 노출합니다. (Contributed by Victor Stinner in bpo-30054 [https://bugs.python.org/issue?@action=redirect&bpo=30054].)

새로운 import__find__load__start()와 import__find__load__done() 정적 마커를 사용하여 모듈 임포트를 추적 할 수 있습니다. (Contributed by Christian Heimes in bpo-31574 [https://bugs.python.org/issue?@action=redirect&bpo=31574].)

The fields name and doc of structures PyMemberDef, PyGetSetDef, PyStructSequence_Field, PyStructSequence_Desc, and wrapperbase are now of type const char * rather of char *. (Contributed by Serhiy Storchaka in bpo-28761 [https://bugs.python.org/issue?@action=redirect&bpo=28761].)

PyUnicode_AsUTF8AndSize() 와 PyUnicode_AsUTF8()의 결과는 이제 char * 이 아니라 const char * 입니다. (Contributed by Serhiy Storchaka in bpo-28769 [https://bugs.python.org/issue?@action=redirect&bpo=28769].)

PyMapping_Keys(), PyMapping_Values() 및 PyMapping_Items()의 결과는 이제 리스트 또는 튜플이 아니라 항상 리스트입니다. (Contributed by Oren Milman in bpo-28280 [https://bugs.python.org/issue?@action=redirect&bpo=28280].)

함수 PySlice_Unpack()과 PySlice_AdjustIndices() 를 추가했습니다. (Contributed by Serhiy Storchaka in bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867].)

PyOS_AfterFork() 는 폐지되고, 새 함수 PyOS_BeforeFork(), PyOS_AfterFork_Parent() 그리고 PyOS_AfterFork_Child()로 대체되었습니다. (Contributed by Antoine Pitrou in bpo-16500 [https://bugs.python.org/issue?@action=redirect&bpo=16500].)

공개 API의 일부였던 PyExc_RecursionErrorInst 싱글톤은 제거되었습니다. 청소되지 않은 멤버가 인터프리터의 파이널리제이션 과정에서 세그멘테이션 오류를 일으킬 수 있기 때문입니다. (Contributed by Xavier de Gaye in bpo-22898 [https://bugs.python.org/issue?@action=redirect&bpo=22898] and bpo-30697 [https://bugs.python.org/issue?@action=redirect&bpo=30697].)

시간대 지원을 위한 timezone 생성자 PyTimeZone_FromOffset() 과 PyTimeZone_FromOffsetAndName() 및 UTC 싱글톤에 액세스하는 PyDateTime_TimeZone_UTC C API 지원을 추가했습니다. (Contributed by Paul Ganssle in bpo-10381 [https://bugs.python.org/issue?@action=redirect&bpo=10381].)

The type of results of PyThread_start_new_thread() and PyThread_get_thread_ident(), and the id parameter of PyThreadState_SetAsyncExc() changed from long to unsigned long. (Contributed by Serhiy Storchaka in bpo-6532 [https://bugs.python.org/issue?@action=redirect&bpo=6532].)

PyUnicode_AsWideCharString() now raises a ValueError if the second argument is NULL and the wchar_t* string contains null characters. (Contributed by Serhiy Storchaka in bpo-30708 [https://bugs.python.org/issue?@action=redirect&bpo=30708].)

시동 절차와 동적 메모리 할당자의 변경으로 인해 대부분의 C API 함수를 호출하기 전에 Py_Initialize() 를 호출해야 한다는 오래전부터 문서화 된 요구 사항이 이제 더 중요해졌고, 이를 지키지 않으면 내장형 응용 프로그램에서 세그멘테이션 오류로 이어질 수 있습니다. 자세한 내용은 이 문서의 파이썬 3.7로 이식하기 절과 C API 설명서의 파이썬 초기화 전 절을 참조하십시오.

새로운 PyInterpreterState_GetID() 는 주어진 인터프리터의 유일한 ID를 반환합니다. (Contributed by Eric Snow in bpo-29102 [https://bugs.python.org/issue?@action=redirect&bpo=29102].)

Py_DecodeLocale(), Py_EncodeLocale() 은 이제 UTF-8 모드 가 활성화될 때 UTF-8 인코딩을 사용합니다. (Contributed by Victor Stinner in bpo-29240 [https://bugs.python.org/issue?@action=redirect&bpo=29240].)

PyUnicode_DecodeLocaleAndSize() 와 PyUnicode_EncodeLocale()은 이제 surrogateescape 에러 처리기에 현재 로케일 인코딩을 사용합니다. (Contributed by Victor Stinner in bpo-29240 [https://bugs.python.org/issue?@action=redirect&bpo=29240].)

PyUnicode_FindChar() 의 start 와 end 매개 변수가 문자열 슬라이스처럼 동작하도록 조정되었습니다. (Contributed by Xiang Zhang in bpo-28822 [https://bugs.python.org/issue?@action=redirect&bpo=28822].)

빌드 변경

--without-threads 빌드 지원이 제거되었습니다. threading 모듈은 이제 항상 사용할 수 있습니다. (Contributed by Antoine Pitrou in bpo-31370 [https://bugs.python.org/issue?@action=redirect&bpo=31370].)

OSX 이외의 유닉스 플랫폼에서 _ctypes 모듈을 빌드할 때 사용되는 libffi의 전체 복사본이 더는 포함되지 않습니다. 이러한 플랫폼에서 _ctypes 를 빌드 할 때 libffi의 설치된 사본이 필요합니다. (Contributed by Zachary Ware in bpo-27979 [https://bugs.python.org/issue?@action=redirect&bpo=27979].)

윈도우 빌드 프로세스는 외부 소스를 가져오는 데 더는 서브버전에 의존하지 않습니다. 대신 파이썬 스크립트를 사용해서 GitHub에서 zip 파일을 내려받습니다. 시스템에서 파이썬 3.6이 발견되지 않으면 (py -3.6 를 통해), 이 목적을 위해 NuGet으로 32-비트 파이썬의 사본을 내려받습니다. (Contributed by Zachary Ware in bpo-30450 [https://bugs.python.org/issue?@action=redirect&bpo=30450].)

ssl 모듈은 OpenSSL 1.0.2 또는 1.1 호환 libssl을 요구합니다. OpenSSL 1.0.1의 유효 기간은 2016-12-31 에 만료되었고 더는 지원되지 않습니다. LibreSSL도 일시적으로 지원되지 않습니다. 버전 2.6.4까지의 LibreSSL 배포에는 필수 OpenSSL 1.0.2 API가 없습니다.

최적화

C로 구현된 다양한 표준 라이브러리 클래스의 많은 메서드를 호출하는 오버헤드가, METH_FASTCALL 규칙을 사용하도록 더 많은 코드를 이식함으로써 상당히 감소하였습니다. (Contributed by Victor Stinner in bpo-29300 [https://bugs.python.org/issue?@action=redirect&bpo=29300], bpo-29507 [https://bugs.python.org/issue?@action=redirect&bpo=29507], bpo-29452 [https://bugs.python.org/issue?@action=redirect&bpo=29452], and bpo-29286 [https://bugs.python.org/issue?@action=redirect&bpo=29286].)

다양한 최적화를 통해 파이썬의 시작 시간을 리눅스에서 10%, macOS에서 최대 30%까지 줄였습니다. (Contributed by Victor Stinner, INADA Naoki in bpo-29585 [https://bugs.python.org/issue?@action=redirect&bpo=29585], and Ivan Levkivskyi in bpo-31333 [https://bugs.python.org/issue?@action=redirect&bpo=31333].)

메서드 호출은 이제 연결된 메서드 인스턴스 생성을 피하는 바이트 코드 변경으로 인해 최대 20% 빨라졌습니다. (Contributed by Yury Selivanov and INADA Naoki in bpo-26110 [https://bugs.python.org/issue?@action=redirect&bpo=26110].)

asyncio 모듈은 자주 사용되는 함수들에 대해 여러 가지 주목할만한 최적화가 이루어졌습니다:

asyncio.get_event_loop() 함수가 C로 다시 구현되어 최대 15배 빨라졌습니다. (Contributed by Yury Selivanov in bpo-32296 [https://bugs.python.org/issue?@action=redirect&bpo=32296].)

asyncio.Future 콜백 관리가 최적화되었습니다. (Contributed by Yury Selivanov in bpo-32348 [https://bugs.python.org/issue?@action=redirect&bpo=32348].)

asyncio.gather() 는 이제 최대 15% 빨라졌습니다. (Contributed by Yury Selivanov in bpo-32355 [https://bugs.python.org/issue?@action=redirect&bpo=32355].)

asyncio.sleep()은 이제 delay 인자가 0이거나 음수일 때 최대 2배 빠릅니다. (Contributed by Andrew Svetlov in bpo-32351 [https://bugs.python.org/issue?@action=redirect&bpo=32351].)

asyncio 디버그 모드의 성능 오버헤드가 감소하였습니다. (Contributed by Antoine Pitrou in bpo-31970 [https://bugs.python.org/issue?@action=redirect&bpo=31970].)

PEP 560 작업 의 결과로, typing 의 임포트 시간이 7배 단축되었으며, 많은 typing 연산이 이제 더 빨라졌습니다. (Contributed by Ivan Levkivskyi in bpo-32226 [https://bugs.python.org/issue?@action=redirect&bpo=32226].)

sorted()와 list.sort() 는 일반적인 사용에 대해 최대 40-75% 더 빠르게 최적화되었습니다. (Contributed by Elliot Gorokhovsky in bpo-28685 [https://bugs.python.org/issue?@action=redirect&bpo=28685].)

dict.copy() 는 이제 5.5 배 빠릅니다. (Contributed by Yury Selivanov in bpo-31179 [https://bugs.python.org/issue?@action=redirect&bpo=31179].)

hasattr()과 getattr()은 이제 name 이 발견되지 않고 obj 가 object.__getattr__() 또는 object.__getattribute__() 를 재정의하지 않을 때 약 4배 빨라졌습니다. (Contributed by INADA Naoki in bpo-32544 [https://bugs.python.org/issue?@action=redirect&bpo=32544].)

문자열에서 특정 유니코드 문자 (가령 우크라이나어 “Є”)를 검색하는 것은 다른 문자를 검색하는 것보다 최대 25배까지 느렸습니다. 이제는 최악의 상황에도 겨우 3배 느립니다. (Contributed by Serhiy Storchaka in bpo-24821 [https://bugs.python.org/issue?@action=redirect&bpo=24821].)

collections.namedtuple() 팩토리가 재구현되어 네임드 튜플을 4 에서 6배 빠르게 생성합니다. (Contributed by Jelle Zijlstra with further improvements by INADA Naoki, Serhiy Storchaka, and Raymond Hettinger in bpo-28638 [https://bugs.python.org/issue?@action=redirect&bpo=28638].)

date.fromordinal() 과 date.fromtimestamp() 는 이제 일반적일 때 최대 30% 더 빠릅니다. (Contributed by Paul Ganssle in bpo-32403 [https://bugs.python.org/issue?@action=redirect&bpo=32403].)

os.fwalk() 함수는 os.scandir() 을 사용함으로써 이제 최대 2배 빨라졌습니다. (Contributed by Serhiy Storchaka in bpo-25996 [https://bugs.python.org/issue?@action=redirect&bpo=25996].)

os.scandir() 함수를 사용하여 shutil.rmtree() 함수의 속도가 20–40% 향상되었습니다. (Contributed by Serhiy Storchaka in bpo-28564 [https://bugs.python.org/issue?@action=redirect&bpo=28564].)

최적화된 정규식 의 대소 문자를 구별하지 않는 매칭과 검색. 일부 패턴 검색은 이제 최대 20배까지 빨라질 수 있습니다. (Contributed by Serhiy Storchaka in bpo-30285 [https://bugs.python.org/issue?@action=redirect&bpo=30285].)

re.compile() 은 이제 flags 매개 변수가 RegexFlag 인 경우 int 객체로 변환합니다. 이제 파이썬 3.5만큼 빠르고, 패턴에 따라 파이썬 3.6보다 약 10% 빠릅니다. (Contributed by INADA Naoki in bpo-31671 [https://bugs.python.org/issue?@action=redirect&bpo=31671].)

클래스 selectors.EpollSelector, selectors.PollSelector 와 selectors.DevpollSelector 의 modify() 메서드는 높은 부하가 걸릴 때 10% 정도 더 빨라질 수 있습니다. (Contributed by Giampaolo Rodola’ in bpo-30014 [https://bugs.python.org/issue?@action=redirect&bpo=30014])

상수 폴딩은 핍홀 최적화기에서 새로운 AST 최적화기로 이동되어, 더욱 일관된 최적화를 수행 할 수 있습니다. (Contributed by Eugene Toder and INADA Naoki in bpo-29469 [https://bugs.python.org/issue?@action=redirect&bpo=29469] and bpo-11549 [https://bugs.python.org/issue?@action=redirect&bpo=11549].)

abc 에 있는 대부분 함수와 메서드는 C로 재작성되었습니다. 이로 인해 추상 베이스 클래스 생성과, 이에 대한 isinstance() 와 issubclass() 호출이 1.5 배 더 빠릅니다. 또한, 파이썬 시작 시간을 최대 10% 단축합니다. (Contributed by Ivan Levkivskyi and INADA Naoki in bpo-31333 [https://bugs.python.org/issue?@action=redirect&bpo=31333])

datetime.date 와 datetime.datetime 의 대체 생성자의 경우, 서브 클래스를 만들지 않을 때 파이썬 생성자를 우회해서 속도가 현저히 향상되었습니다. (Contributed by Paul Ganssle in bpo-32403 [https://bugs.python.org/issue?@action=redirect&bpo=32403])

array.array 인스턴스의 비교 속도가 어떤 경우에는 상당히 향상되었습니다. 같은 정수 형의 값을 보유한 배열을 비교할 때, 이제는 10배에서 70배 빠릅니다. (Contributed by Adrian Wielgosik in bpo-24700 [https://bugs.python.org/issue?@action=redirect&bpo=24700].)

math.erf() 와 math.erfc() 함수는 이제 대부분 플랫폼에서 (더 빠른) C 라이브러리 구현을 사용합니다. (Contributed by Serhiy Storchaka in bpo-26121 [https://bugs.python.org/issue?@action=redirect&bpo=26121].)

기타 CPython 구현 변경

Trace hooks may now opt out of receiving the line and opt into receiving the opcode events from the interpreter by setting the corresponding new f_trace_lines and f_trace_opcodes attributes on the frame being traced. (Contributed by Nick Coghlan in bpo-31344 [https://bugs.python.org/issue?@action=redirect&bpo=31344].)

이름 공간 패키지 모듈 어트리뷰트에 대한 일관성 문제를 수정했습니다. 이름 공간 모듈 객체는 이제 __file__ 을 None (이전에는 설정되지 않았습니다)으로 설정하고, __spec__.origin 도 None (이전에는 문자열 "namespace")으로 설정됩니다. bpo-32305 [https://bugs.python.org/issue?@action=redirect&bpo=32305]를 참조하세요. 또한, 이름 공간 모듈 객체의 __spec__.loader 는 __loader__ 와 같은 값으로 설정됩니다 (이전에는 None 으로 설정되었습니다). bpo-32303 [https://bugs.python.org/issue?@action=redirect&bpo=32303]을 참조하세요.

locals() 딕셔너리는 이제 변수가 정의된 어휘 순서로 표시됩니다. 이전에는 순서가 정의되지 않았습니다. (Contributed by Raymond Hettinger in bpo-32690 [https://bugs.python.org/issue?@action=redirect&bpo=32690].)

The distutils upload command no longer tries to change CR end-of-line characters to CRLF. This fixes a corruption issue with sdists that ended with a byte equivalent to CR. (Contributed by Bo Bayles in bpo-32304 [https://bugs.python.org/issue?@action=redirect&bpo=32304].)

폐지된 파이썬 동작

일드 표현식(yield 와 yield from 절 모두)은 이제 컴프리헨션과 제너레이터 표현식에서 폐지되었습니다 (가장 왼쪽의 for 절의 이터러블 표현식은 제외합니다). 이것은 컴프리헨션이 언제나 적절한 유형의 컨테이너를 즉시 반환하도록 하고(잠재적으로 제너레이터 이터레이터 객체를 반환하는 것이 아니라), 제너레이터 표현식이 명시적 일드 표현식의 출력 중간에 묵시적 출력을 끼워 넣으려고 시도하지 못하게 하기 위함입니다. 파이썬 3.7에서 이러한 표현식은 컴파일될 때 DeprecationWarning 을 내보내고, 파이썬 3.8에서는 SyntaxError 가 됩니다. (Contributed by Serhiy Storchaka in bpo-10544 [https://bugs.python.org/issue?@action=redirect&bpo=10544].)

complex 의 서브 클래스를 object.__complex__() 에서 반환하는 것은 폐지되었고, 향후 파이썬 버전에서 에러가 발생할 것입니다. 이것은 __complex__() 를 object.__int__() 및 object.__float__() 와 일관성 있도록 만듭니다. (Contributed by Serhiy Storchaka in bpo-28894 [https://bugs.python.org/issue?@action=redirect&bpo=28894].)

폐지된 파이썬 모듈, 함수 및 메서드

aifc

aifc.openfp() has been deprecated and will be removed in Python 3.9. Use aifc.open() instead. (Contributed by Brian Curtin in bpo-31985 [https://bugs.python.org/issue?@action=redirect&bpo=31985].)

asyncio

asyncio.Lock 및 다른 asyncio 동기화 프리미티브의 인스턴스를 직접 await 하는 지원은 폐지되었습니다. 동기화 자원을 획득하고 해제하기 위해서는 비동기 컨텍스트 관리자를 사용해야 합니다. (Contributed by Andrew Svetlov in bpo-32253 [https://bugs.python.org/issue?@action=redirect&bpo=32253].)

The asyncio.Task.current_task() and asyncio.Task.all_tasks() methods have been deprecated. (Contributed by Andrew Svetlov in bpo-32250 [https://bugs.python.org/issue?@action=redirect&bpo=32250].)

collections

파이썬 3.8에서, collections.abc 의 추상 베이스 클래스는 더는 collections 모듈에 노출되지 않습니다. 이것은 구상 클래스와 추상 베이스 클래스 사이의 명확한 구분을 만드는 데 도움이 됩니다. (Contributed by Serhiy Storchaka in bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988].)

dbm

dbm.dumb 은 이제 읽기 전용 파일 읽기를 지원하며 변경되지 않았을 때 더는 색인 파일을 쓰지 않습니다. 'r' 및 'w' 모드에서 색인 파일이 빠지고 새로 만들어지면, 이제 폐지 경고가 표시됩니다 (향후의 파이썬 배포에서는 에러가 발생합니다). (Contributed by Serhiy Storchaka in bpo-28847 [https://bugs.python.org/issue?@action=redirect&bpo=28847].)

enum

파이썬 3.8에서, Enum 클래스에서 열거형 이외의 객체가 포함되었는지 검사하려고 하면 TypeError 가 발생합니다 (예 1 in Color); 마찬가지로 플래그가 아닌 객체를 Flag 멤버에 포함되었는지 검사하려고 하면 TypeError 가 발생합니다 (예 1 in Perm.RW); 현재 두 연산 모두 대신 False를 반환합니다. (Contributed by Ethan Furman in bpo-33217 [https://bugs.python.org/issue?@action=redirect&bpo=33217].)

gettext

gettext 에서 복수형을 선택하기 위해 정수가 아닌 값을 사용하는 것이 폐지되었습니다. 올바르게 작동된 적이 없습니다. (Contributed by Serhiy Storchaka in bpo-28692 [https://bugs.python.org/issue?@action=redirect&bpo=28692].)

importlib

Methods MetaPathFinder.find_module() (replaced by MetaPathFinder.find_spec()) and PathEntryFinder.find_loader() (replaced by PathEntryFinder.find_spec()) both deprecated in Python 3.4 now emit DeprecationWarning. (Contributed by Matthias Bussonnier in bpo-29576 [https://bugs.python.org/issue?@action=redirect&bpo=29576].)

importlib.abc.ResourceLoader ABC는 폐지되었고, 대신 importlib.abc.ResourceReader 를 사용합니다.

locale

locale.format() 은 폐지되었습니다. 대신 locale.format_string()을 사용하십시오. (Contributed by Garvit in bpo-10379 [https://bugs.python.org/issue?@action=redirect&bpo=10379].)

macpath

macpath 는 이제 폐지되었고 파이썬 3.8에서 제거될 것입니다. (Contributed by Chi Hsuan Yen in bpo-9850 [https://bugs.python.org/issue?@action=redirect&bpo=9850].)

threading

dummy_threading and _dummy_thread have been deprecated. It is no longer possible to build Python with threading disabled. Use threading instead. (Contributed by Antoine Pitrou in bpo-31370 [https://bugs.python.org/issue?@action=redirect&bpo=31370].)

socket

socket.htons() 와 socket.ntohs() 에서 자동 인자 값 자름은 폐지되었습니다. 이후 버전의 파이썬에서는 전달된 인자가 16비트보다 큰 경우 예외가 발생합니다. (Contributed by Oren Milman in bpo-28332 [https://bugs.python.org/issue?@action=redirect&bpo=28332].)

ssl

ssl.wrap_socket() 은 폐지되었습니다. 대신 ssl.SSLContext.wrap_socket()을 사용하십시오. (Contributed by Christian Heimes in bpo-28124 [https://bugs.python.org/issue?@action=redirect&bpo=28124].)

sunau

sunau.openfp() has been deprecated and will be removed in Python 3.9. Use sunau.open() instead. (Contributed by Brian Curtin in bpo-31985 [https://bugs.python.org/issue?@action=redirect&bpo=31985].)

sys

sys.set_coroutine_wrapper()와 sys.get_coroutine_wrapper()를 폐지했습니다.

문서로 만들어지지 않은 sys.callstats() 함수는 폐지되었고 향후 파이썬 버전에서 제거될 것입니다. (Contributed by Victor Stinner in bpo-28799 [https://bugs.python.org/issue?@action=redirect&bpo=28799].)

wave

wave.openfp() 는 폐지되었고 파이썬 3.9에서 제거될 것입니다. 대신 wave.open() 을 사용하십시오. (Contributed by Brian Curtin in bpo-31985 [https://bugs.python.org/issue?@action=redirect&bpo=31985].)

폐지된 C API의 함수 및 형

함수 PySlice_GetIndicesEx() 는 폐지되었고, Py_LIMITED_API 가 설정되어 있지 않거나, 0x03050400 과 0x03060000 (포함되지 않음) 사이의 값이나 0x03060100 이상의 값으로 설정되어 있으면 매크로로 대체됩니다. (Contributed by Serhiy Storchaka in bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867].)

PyOS_AfterFork() 는 폐지되었습니다. PyOS_BeforeFork(), PyOS_AfterFork_Parent() 또는 PyOS_AfterFork_Child() 를 대신 사용하십시오. (Contributed by Antoine Pitrou in bpo-16500 [https://bugs.python.org/issue?@action=redirect&bpo=16500].)

플랫폼 지원 제거

FreeBSD 9와 그 이전 버전은 더는 공식적으로 지원되지 않습니다.

확장 모듈 내를 포함하여, 완전한 유니코드 지원을 위해 유닉스 플랫폼은 이제 레거시 ASCII 기반 C 로케일의 대안으로, C.UTF-8 (전체 로케일), C.utf8 (전체 로케일) 또는 UTF-8 (LC_CTYPE 전용 로케일) 중 적어도 하나를 제공할 것으로 기대됩니다.

OpenSSL 0.9.8 및 1.0.1은 더는 지원되지 않습니다. 이는 여전히 이 버전을 사용하는 이전 플랫폼에서 SSL/TLS를 지원하는 CPython 3.7을 빌드하려면 최신 버전의 OpenSSL에 링크되는 사용자 정의 빌드 옵션이 필요함을 뜻합니다.

특히, 이 문제는 Debian 8 (일명 “jessie”) 및 Ubuntu 14.04 (일명 “Trusty”) LTS 리눅스 배포판에 영향을 미칩니다. 아직 OpenSSL 1.0.1을 기본적으로 사용하기 때문입니다.

Debian 9 (“stretch”) 및 Ubuntu 16.04 (“xenial”) 는, 다른 LTS 리눅스 배포판(가령, RHEL/CentOS 7.5, SLES 12-SP3)의 최신 릴리스 역시, OpenSSL 1.0.2 이상을 사용하고, 기본 빌드 구성에서 여전히 지원됩니다.

CPython’s own CI configuration file [https://github.com/python/cpython/blob/v3.7.13/.travis.yml] provides an example of using the SSL compatibility testing infrastructure [https://github.com/python/cpython/tree/main/Tools/ssl/multissltests.py] in CPython’s test suite to build and link against OpenSSL 1.1.0 rather than an outdated system provided OpenSSL.

API 및 기능 제거

다음 기능과 API는 파이썬 3.7에서 제거되었습니다:

os.stat_float_times() 함수가 제거되었습니다. 이것은 파이썬 2.2와의 하위 호환성을 위해 파이썬 2.3에서 소개되었으며 파이썬 3.1부터 폐지되었습니다.

re.sub() 의 대체 템플릿에 있는 '\' 와 ASCII 글자로 이루어진 알 수 없는 이스케이프는 파이썬 3.5에서 폐지되었고, 이제는 에러를 일으킵니다.

tarfile.TarFile.add() 에서 exclude 인자의 지원이 제거되었습니다. 파이썬 2.7 및 3.2에서 폐지되었습니다. 대신 filter 인자를 사용하십시오.

The ntpath.splitunc() function was deprecated in Python 3.1, and has now been removed. Use splitdrive() instead.

collections.namedtuple()은 네임드 튜플 클래스에 대해 생성된 소스 코드를 보여주는 verbose 매개 변수 나 _source 어트리뷰트를 더는 지원하지 않습니다. 이것은 클래스 생성 속도를 높이기 위해 고안된 최적화 일부입니다. (Contributed by Jelle Zijlstra with further improvements by INADA Naoki, Serhiy Storchaka, and Raymond Hettinger in bpo-28638 [https://bugs.python.org/issue?@action=redirect&bpo=28638].)

함수 bool(), float(), list() 그리고 tuple() 은 더는 키워드 인자를 취하지 않습니다. int() 의 첫 번째 인자는 이제 위치 인자로만 전달될 수 있습니다.

plistlib 모듈에서, 이전에 파이썬 2.4에서 폐지된 클래스 Plist, Dict, _InternalDict 가 제거되었습니다. readPlist() 함수와 readPlistFromBytes() 함수의 결과에서 Dict 값은 이제 정상적인 딕셔너리입니다. 더는 어트리뷰트 액세스를 사용하여 이러한 딕셔너리의 항목에 액세스할 수 없습니다.

asyncio.windows_utils.socketpair() 함수가 삭제되었습니다. 대신에 socket.socketpair() 함수를 사용하십시오. 파이썬 3.5부터 모든 플랫폼에서 사용할 수 있습니다. asyncio.windows_utils.socketpair 는 파이썬 3.5 이상에서 socket.socketpair 의 별칭이었습니다.

asyncio no longer exports the selectors and _overlapped modules as asyncio.selectors and asyncio._overlapped. Replace from asyncio import selectors with import selectors.

ssl.SSLSocket 과 ssl.SSLObject 객체의 직접적인 인스턴스 생성이 금지되었습니다. 생성자는 공개 생성자로서 문서화, 테스트 또는 설계되지 않았습니다. 사용자는 ssl.wrap_socket() 또는 ssl.SSLContext 를 사용해야 합니다. (Contributed by Christian Heimes in bpo-32951 [https://bugs.python.org/issue?@action=redirect&bpo=32951].)

The unused distutils install_misc command has been removed. (Contributed by Eric N. Vander Weele in bpo-29218 [https://bugs.python.org/issue?@action=redirect&bpo=29218].)

모듈 제거

fpectl 모듈이 삭제되었습니다. 기본적으로 활성화된 적이 없고, x86-64에서 제대로 작동한 적도 없고, 예기치 않게 C 확장을 깨뜨리는 방식으로 파이썬 ABI를 변경했습니다. (Contributed by Nathaniel J. Smith in bpo-29137 [https://bugs.python.org/issue?@action=redirect&bpo=29137].)

윈도우 전용 변경

파이썬 런처(py.exe)는 32비트와 64비트 지정자를 받아들일 수 있는데, 마이너 버전을 지정하지 않아도 됩니다. 그래서 py -3.7-32 뿐만 아니라 py -3-32 와 py -3-64 도 유효합니다. 또한 -m-64와 -m.n-64 형식도 이제 받아들이는데, 지정하지 않을 때 32비트가 사용되는 경우도 64비트 파이썬을 강제합니다. 지정된 버전을 사용할 수 없는 경우 py.exe가 에러를 일으키며 종료됩니다. (Contributed by Steve Barnes in bpo-30291 [https://bugs.python.org/issue?@action=redirect&bpo=30291].)

런처는 py -0 처럼 실행시킬 수 있는데, 설치되어있는 파이썬의 목록을 만들고, 기본값을 애스터리스크로 표시합니다. py -0p 를 실행하면 경로가 포함됩니다. py가 일치할 수 없는 버전 지정자로 실행되면 사용 가능한 지정자의 짧은 양식 목록도 인쇄됩니다. (Contributed by Steve Barnes in bpo-30362 [https://bugs.python.org/issue?@action=redirect&bpo=30362].)

파이썬 3.7로 이식하기

이 섹션에서는 여러분의 코드 수정을 요구하는 앞서 설명한 변경 사항과 버그 수정을 나열합니다.

파이썬 동작의 변경

async와 await 이름은 이제 예약 키워드입니다. 이 이름을 식별자로 사용하는 코드는 이제 SyntaxError 를 발생시킵니다. (Contributed by Jelle Zijlstra in bpo-30406 [https://bugs.python.org/issue?@action=redirect&bpo=30406].)

PEP 479 [https://peps.python.org/pep-0479/] 는 파이썬 3.7의 모든 코드에서 활성화되었습니다. 즉 코루틴과 제너레이터에서 직접 또는 간접적으로 발생하는 StopIteration 예외는 RuntimeError 예외로 변환됩니다. (Contributed by Yury Selivanov in bpo-32670 [https://bugs.python.org/issue?@action=redirect&bpo=32670].)

object.__aiter__() 메서드는 더는 비동기로 선언될 수 없습니다. (Contributed by Yury Selivanov in bpo-31709 [https://bugs.python.org/issue?@action=redirect&bpo=31709].)

못 보고 넘기는 바람에, 이전 파이썬 버전에서 다음 문법이 받아들여 지는 잘못이 있었습니다:

f(1 for x in [1],)

class C(1 for x in [1]):
    pass

파이썬 3.7은 이제 올바르게 SyntaxError 를 일으킵니다. 제너레이터 표현식은 항상 괄호 안에 바로 들어가 있어야 하며 양쪽에 쉼표를 넣을 수 없고 중복된 괄호는 오직 호출 시에만 생략 할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-32012 [https://bugs.python.org/issue?@action=redirect&bpo=32012] and bpo-32023 [https://bugs.python.org/issue?@action=redirect&bpo=32023].)

-m 스위치를 사용할 때, 이제 빈 문자열 대신에 초기 작업 디렉터리가 sys.path 에 추가됩니다 (빈 문자열은 각 임포트 시점의 작업 디렉터리가 동적으로 적용되게 만듭니다). 빈 문자열을 검사하는 프로그램이나 이전 동작에 의존하는 프로그램은 그에 따라 업데이트해야 합니다 (예를 들어, 왜 코드가 빈 문자열을 검사했는지에 따라 os.getcwd() 또는 os.path.dirname(__main__.__file__) 도 검사해서).

파이썬 API의 변경

socketserver.ThreadingMixIn.server_close() 는 이제 모든 데몬이 아닌 스레드가 완료될 때까지 대기합니다. 3.7 이전의 동작을 얻으려면 새로운 socketserver.ThreadingMixIn.block_on_close 클래스 어트리뷰트를 False 로 설정하십시오. (Contributed by Victor Stinner in bpo-31233 [https://bugs.python.org/issue?@action=redirect&bpo=31233] and bpo-33540 [https://bugs.python.org/issue?@action=redirect&bpo=33540].)

socketserver.ForkingMixIn.server_close() 는 이제 모든 자식 프로세스가 완료될 때까지 대기합니다. 3.7 이전의 동작을 얻으려면 새로운 socketserver.ForkingMixIn.block_on_close 클래스 어트리뷰트를 False 로 설정하십시오. (Contributed by Victor Stinner in bpo-31151 [https://bugs.python.org/issue?@action=redirect&bpo=31151] and bpo-33540 [https://bugs.python.org/issue?@action=redirect&bpo=33540].)

locale.localeconv() 함수는 이제 일시적으로 LC_CTYPE 로케일을 LC_NUMERIC 의 값으로 설정하는 때도 있습니다. (Contributed by Victor Stinner in bpo-31900 [https://bugs.python.org/issue?@action=redirect&bpo=31900].)

pkgutil.walk_packages() 는 path 가 문자열이면 ValueError 를 발생시킵니다. 이전에는 빈 리스트가 반환되었습니다. (Contributed by Sanyam Khurana in bpo-24744 [https://bugs.python.org/issue?@action=redirect&bpo=24744].)

string.Formatter.format() 의 포맷 문자열 인자는 이제 위치-전용 입니다. 키워드 인자로 전달하는 것은 파이썬 3.5에서 폐지되었습니다. (Contributed by Serhiy Storchaka in bpo-29193 [https://bugs.python.org/issue?@action=redirect&bpo=29193].)

클래스 http.cookies.Morsel 의 어트리뷰트 key, value 및 coded_value 는 이제 읽기 전용입니다. 그들에게 대입하는 것은 파이썬 3.5에서 폐지되었습니다. 그것들을 설정하려면 set() 메서드를 사용하십시오. (Contributed by Serhiy Storchaka in bpo-29192 [https://bugs.python.org/issue?@action=redirect&bpo=29192].)

The mode argument of os.makedirs() no longer affects the file permission bits of newly created intermediate-level directories. To set their file permission bits you can set the umask before invoking makedirs(). (Contributed by Serhiy Storchaka in bpo-19930 [https://bugs.python.org/issue?@action=redirect&bpo=19930].)

struct.Struct.format 형은 이제 bytes 가 아니라 str 입니다. (Contributed by Victor Stinner in bpo-21071 [https://bugs.python.org/issue?@action=redirect&bpo=21071].)

cgi.parse_multipart() now accepts the encoding and errors arguments and returns the same results as FieldStorage: for non-file fields, the value associated to a key is a list of strings, not bytes. (Contributed by Pierre Quentel in bpo-29979 [https://bugs.python.org/issue?@action=redirect&bpo=29979].)

socket 의 내부 변경으로 인해, 이번 버전의 파이썬에서 socket.share 로 만들어진 소켓에 socket.fromshare() 를 호출하는 것은 지원되지 않습니다.

BaseException 의 repr 은 후행 쉼표를 포함하지 않도록 변경되었습니다. 대부분의 예외는 이 변경의 영향을 받습니다. (Contributed by Serhiy Storchaka in bpo-30399 [https://bugs.python.org/issue?@action=redirect&bpo=30399].)

datetime.timedelta 의 repr 은 키워드 인자를 출력에 포함하도록 변경되었습니다. (Contributed by Utkarsh Upadhyay in bpo-30302 [https://bugs.python.org/issue?@action=redirect&bpo=30302].)

shutil.rmtree() 는 이제 os.scandir() 함수를 사용하여 구현되었으므로, 사용자 지정 처리기 onerror 는 이제 디렉터리의 목록을 얻는 데 실패하면 첫 번째 인자가 os.listdir 대신 os.scandir 로 호출됩니다.

유니코드 기술 표준 #18 [https://unicode.org/reports/tr18/] 과같이 정규 표현식에서 중첩 집합 및 집합 연산에 대한 지원이 향후 추가될 수 있습니다. 그러면 문법이 변경됩니다. 미래의 변화를 촉진하기 위해 당분간 모호한 경우에 FutureWarning 를 일으킬 것입니다. 이 경우는 리터럴 '[' 로 시작하거나 리터럴 문자 '--', '&&', '~~' 및 '||' 을 포함하는 집합을 포함합니다. 경고를 피하려면 백 슬래시로 이스케이프 처리하십시오. (Contributed by Serhiy Storchaka in bpo-30349 [https://bugs.python.org/issue?@action=redirect&bpo=30349].)

빈 문자열과 일치 할 수 있는 정규식 으로 문자열을 나눈 결과가 변경되었습니다. 예를 들어, r'\s*' 로 나누면, 이전처럼 공백 문자뿐만 아니라, 공백 문자가 아닌 문자의 앞과 문자열 끝 바로 직전의 빈 문자열로도 나눕니다. 패턴을 r'\s+' 로 변경하면 이전의 동작을 복원 할 수 있습니다. 파이썬 3.5부터 그러한 패턴에 대해 FutureWarning 을 만들었습니다.

빈 문자열과 비어 있지 않은 문자열 모두와 일치하는 패턴의 경우, 모든 일치를 검색한 결과가 다른 경우에도 변경될 수 있습니다. 예를 들어, 문자열 'a\n\n' 에서, 패턴 r'(?m)^\s*?$' 는 위치 2와 3의 빈 문자열을 일치시킬 뿐만 아니라, 위치 2–3의 문자열 '\n' 도 일치시킵니다. 빈 줄만 일치시키려면, 패턴을 r'(?m)^[^\S\n]*$' 으로 다시 써야 합니다.

re.sub() now replaces empty matches adjacent to a previous non-empty match. For example re.sub('x*', '-', 'abxd') returns now '-a-b--d-' instead of '-a-b-d-' (the first minus between ‘b’ and ‘d’ replaces ‘x’, and the second minus replaces an empty string between ‘x’ and ‘d’).

(Contributed by Serhiy Storchaka in bpo-25054 [https://bugs.python.org/issue?@action=redirect&bpo=25054] and bpo-32308 [https://bugs.python.org/issue?@action=redirect&bpo=32308].)

변경 re.escape() 가 ASCII 문자, 숫자 및 '_' 이외의 모든 문자를 이스케이프 하는 대신 정규식 특수 문자만 이스케이프 하도록 변경합니다. (Contributed by Serhiy Storchaka in bpo-29995 [https://bugs.python.org/issue?@action=redirect&bpo=29995].)

tracemalloc.Traceback 프레임은 이제 가장 오래된 것부터 가장 최근의 것 순으로 정렬되어, traceback 과 더 일관성 있게 만듭니다. (Contributed by Jesse Bakker in bpo-32121 [https://bugs.python.org/issue?@action=redirect&bpo=32121].)

socket.SOCK_NONBLOCK 또는 socket.SOCK_CLOEXEC 비트 플래그를 지원하는 OS에서, socket.type 에 이것들을 더는 적용하지 않습니다. 따라서 if sock.type == socket.SOCK_STREAM 과 같은 검사는 모든 플랫폼에서 예상대로 작동합니다. (Contributed by Yury Selivanov in bpo-32331 [https://bugs.python.org/issue?@action=redirect&bpo=32331].)

윈도우에서 표준 핸들을 리디렉션 할 때 subprocess.Popen 의 close_fds 인자의 기본값이 False 에서 True 로 변경되었습니다. 이전에 표준 입출력 리디렉션으로 subprocess.Popen 을 사용할 때 상속된 핸들에 의존했다면, 이전 동작을 유지하기 위해서 close_fds=False 를 넘기거나 STARTUPINFO.lpAttributeList 를 사용해야 합니다.

importlib.machinery.PathFinder.invalidate_caches() – 묵시적으로 importlib.invalidate_caches() 에 영향을 줍니다 – 는 이제 sys.path_importer_cache 에서 None 으로 설정된 엔트리를 삭제합니다. (Contributed by Brett Cannon in bpo-33169 [https://bugs.python.org/issue?@action=redirect&bpo=33169].)

asyncio 에서, loop.sock_recv(), loop.sock_sendall(), loop.sock_accept(), loop.getaddrinfo(), loop.getnameinfo() 는 문서와 일치하도록 적절한 코루틴 메서드로 변경되었습니다. 이전에는, 이 메서드는 asyncio.Future 인스턴스를 반환했습니다. (Contributed by Yury Selivanov in bpo-32327 [https://bugs.python.org/issue?@action=redirect&bpo=32327].)

asyncio.Server.sockets 는 이제 내부 서버 소켓 리스트를 직접 돌려주는 대신 사본을 반환합니다. (Contributed by Yury Selivanov in bpo-32662 [https://bugs.python.org/issue?@action=redirect&bpo=32662].)

Struct.format 는 bytes 인스턴스 대신에 str 인스턴스가 되었습니다. (Contributed by Victor Stinner in bpo-21071 [https://bugs.python.org/issue?@action=redirect&bpo=21071].)

required=True를 ArgumentParser.add_subparsers()로 전달하여 argparse 부속 파서를 필수로 만들 수 있습니다. (Contributed by Anthony Sottile in bpo-26510 [https://bugs.python.org/issue?@action=redirect&bpo=26510].)

ast.literal_eval() is now stricter. Addition and subtraction of arbitrary numbers are no longer allowed. (Contributed by Serhiy Storchaka in bpo-31778 [https://bugs.python.org/issue?@action=redirect&bpo=31778].)

Calendar.itermonthdates 는 이제 날짜가 0001-01-01 에서 9999-12-31 범위를 벗어나면 일관되게 예외를 일으킵니다. 이러한 예외를 허용할 수 없는 응용 프로그램을 지원하기 위해 새로운 Calendar.itermonthdays3 와 Calendar.itermonthdays4 를 사용할 수 있습니다. 새로운 메서드는 튜플을 반환하고 datetime.date 에 의해 지원되는 범위에 제한받지 않습니다. (Contributed by Alexander Belopolsky in bpo-28292 [https://bugs.python.org/issue?@action=redirect&bpo=28292].)

collections.ChainMap 은 이제 하부 매핑의 순서를 보존합니다. (Contributed by Raymond Hettinger in bpo-32792 [https://bugs.python.org/issue?@action=redirect&bpo=32792].)

concurrent.futures.ThreadPoolExecutor 와 concurrent.futures.ProcessPoolExecutor 의 submit() 메서드는 인터프리터가 종료하는 동안 호출되면 RuntimeError 를 발생시킵니다. (Contributed by Mark Nemec in bpo-33097 [https://bugs.python.org/issue?@action=redirect&bpo=33097].)

configparser.ConfigParser 생성자는 read_dict() 를 사용하여 기본값을 처리해서, 그 동작을 파서의 나머지와 일관되게 합니다. 이제 기본 딕셔너리의 문자열이 아닌 키와 값은 묵시적으로 문자열로 변환됩니다. (Contributed by James Tocknell in bpo-23835 [https://bugs.python.org/issue?@action=redirect&bpo=23835].)

문서로 만들어지지 않은 여러 가지 내부 임포트가 제거되었습니다. 한 가지 예는 os.errno를 더는 사용할 수 없다는 것입니다; 대신 import errno를 직접 사용하십시오. 이러한 문서로 만들어지지 않은 내부 임포트는, 마이크로 버전 배포에서도, 언제든지 예고 없이 삭제될 수 있음에 유의하십시오.

C API의 변경

함수 PySlice_GetIndicesEx() 는 크기 조절이 가능한 시퀀스에 대해 안전하지 않은 것으로 간주합니다. 슬라이스 인덱스가 int 의 인스턴스가 아니라 __index__() 메서드를 구현하는 객체인 경우, 시퀀스는 길이를 PySlice_GetIndicesEx() 에 전달한 후 크기를 조정할 수 있습니다. 이로 인해 시퀀스의 길이를 벗어나는 인덱스가 반환될 수 있습니다. 가능한 문제를 피하려면 PySlice_Unpack()과 PySlice_AdjustIndices() 라는 새로운 함수를 사용하십시오. (Contributed by Serhiy Storchaka in bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867].)

CPython 바이트 코드 변경

There are two new opcodes: LOAD_METHOD and CALL_METHOD. (Contributed by Yury Selivanov and INADA Naoki in bpo-26110 [https://bugs.python.org/issue?@action=redirect&bpo=26110].)

The STORE_ANNOTATION opcode has been removed. (Contributed by Mark Shannon in bpo-32550 [https://bugs.python.org/issue?@action=redirect&bpo=32550].)

윈도우 전용 변경

The file used to override sys.path is now called <python-executable>._pth instead of 'sys.path'. See 모듈 찾기 for more information. (Contributed by Steve Dower in bpo-28137 [https://bugs.python.org/issue?@action=redirect&bpo=28137].)

기타 CPython 구현 변경

공개된 CPython 실행시간 초기화 API에 가해질 잠재적인 미래의 변경을 준비하기 위해 (초기의, 하지만 약간 낡은 초안은 PEP 432 [https://peps.python.org/pep-0432/]를 보십시오), CPython의 내부 시작 및 구성 관리 로직이 상당히 리팩토링 되었습니다. 이러한 업데이트는 내장형 응용 프로그램과 일반 CPython CLI의 사용자 모두에게 완전히 투명하도록 의도했지만, 리팩토링 변경이 인터프리터 시작 시 다양한 작업의 내부 순서를 변경하므로 내장형 응용 프로그램과 CPython 자체에서 잠재 결함을 드러낼 수 있으므로 여기에서 언급합니다. (처음에는 Nick Coghlan과 Eric Snow가 bpo-22257 [https://bugs.python.org/issue?@action=redirect&bpo=22257] 의 일부로 이바지했고, Nick, Eric, Victor Stinner가 여러 이슈를 통해 추가로 업데이트했습니다). 영향을 받는 일부 알려진 세부 정보는 이렇습니다:

PySys_AddWarnOptionUnicode() is not currently usable by embedding applications due to the requirement to create a Unicode object prior to calling Py_Initialize. Use PySys_AddWarnOption() instead.

warnings filters added by an embedding application with PySys_AddWarnOption() should now more consistently take precedence over the default filters set by the interpreter

기본 경고 필터가 구성되는 방식의 변경으로 인해, Py_BytesWarningFlag 를 1보다 큰 값으로 설정하는 것이 더는 BytesWarning 메시지를 내보내면서 동시에 예외로 변환되도록 하기에 충분하지 못합니다. 대신, 플래그를 설정해야 하고 (경고가 처음에 발생하도록), 예외로 변환하기 위해 명시적으로 error::BytesWarning 경고 필터를 추가해야 합니다.

컴파일러가 독스트링을 처리하는 방식의 변화 때문에, 독스트링만으로 구성된 함수 바디의 묵시적인 return None 은, 이제 함수의 헤더 행이 아니라 독스트링과 같은 줄에 등장하는 것으로 표시됩니다.

현재 예외 상태가 프레임 객체에서 코루틴으로 옮겨졌습니다. 이는 인터프리터를 간소화하고 제너레이터에 들어가거나 빠져나갈 때 예외 상태를 스와프함으로써 발생하는 모호한 두 가지 버그를 수정했습니다. (Contributed by Mark Shannon in bpo-25612 [https://bugs.python.org/issue?@action=redirect&bpo=25612].)

파이썬 3.7.1의 주목할만한 변경 사항

3.7.1부터, Py_Initialize()는 이제 Py_Main()과 같은 환경 설정을 일관되게 읽고 존중합니다 (이전 파이썬 버전에서는, 환경 변수 중 잘 정의되지 않은 부분 집합을 존중했지만 파이썬 3.7.0에서는 bpo-34247 [https://bugs.python.org/issue?@action=redirect&bpo=34247]로 인해 아무것도 읽지 않았습니다). 이 동작을 원하지 않으면, Py_Initialize()를 호출하기 전에 Py_IgnoreEnvironmentFlag를 1로 설정하십시오.

3.7.1에서, 컨텍스트 변수를 위한 C API는 PyObject 포인터를 사용하도록 변경되었습니다. bpo-34762 [https://bugs.python.org/issue?@action=redirect&bpo=34762]를 참조하세요.

3.7.1에서, tokenize 모듈은 끝에 줄 바꿈이 없는 입력이 제공될 때 묵시적으로 NEWLINE 토큰을 산출합니다. 이 동작은 이제 C 토크나이저가 내부적으로 수행하는 것과 일치합니다. (Contributed by Ammar Askar in bpo-33899 [https://bugs.python.org/issue?@action=redirect&bpo=33899].)

파이썬 3.7.2의 주목할만한 변경 사항

3.7.2에서, 윈도우에서 venv는 더는 원본 바이너리를 복사하지 않고, 대신 python.exe 와 pythonw.exe라는 리디렉터 스크립트를 만듭니다. 이렇게 하면 각 파이썬 업데이트마다 모든 가상 환경을 업그레이드하거나 다시 만들어야 하는 오랜 문제를 해결할 수 있습니다. 그러나, 이 배포에서는 새 스크립트를 얻기 위해 가상 환경을 다시 만들어야 함에 유의하세요.

파이썬 3.7.6의 주목할만한 변경 사항

심각한 보안 문제로 인해, asyncio.loop.create_datagram_endpoint()의 reuse_address 매개 변수는 더는 지원되지 않습니다. 이것은 UDP에서 소켓 옵션 SO_REUSEADDR의 동작 때문입니다. 자세한 내용은 loop.create_datagram_endpoint() 설명서를 참조하십시오. (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228].)

파이썬 3.7.10의 주목할만한 변경 사항

Earlier Python versions allowed using both ; and & as query parameter separators in urllib.parse.parse_qs() and urllib.parse.parse_qsl(). Due to security concerns, and to conform with newer W3C recommendations, this has been changed to allow only a single separator key, with & as the default. This change also affects cgi.parse() and cgi.parse_multipart() as they use the affected functions internally. For more details, please see their respective documentation. (Contributed by Adam Goldschmidt, Senthil Kumaran and Ken Jin in bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967].)

Notable changes in Python 3.7.11

A security fix alters the ftplib.FTP behavior to not trust the IPv4 address sent from the remote server when setting up a passive data channel. We reuse the ftp server IP address instead. For unusual code requiring the old behavior, set a trust_server_pasv_ipv4_address attribute on your FTP instance to True. (See gh-87451 [https://github.com/python/cpython/issues/87451])

The presence of newline or tab characters in parts of a URL allows for some forms of attacks. Following the WHATWG specification that updates RFC 3986, ASCII newline \n, \r and tab \t characters are stripped from the URL by the parser urllib.parse() preventing such attacks. The removal characters are controlled by a new module level variable urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE. (See gh-88048 [https://github.com/python/cpython/issues/88048])

Notable security feature in 3.7.14

Converting between int and str in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises a ValueError if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735]. This limit can be configured or disabled by environment variable, command line flag, or sys APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.

파이썬 3.6의 새로운 기능

편집자:

Elvis Pranskevichus <elvis@magic.io>, Yury Selivanov <yury@magic.io>

이 기사에서는 3.5와 비교하여 파이썬 3.6의 새로운 기능을 설명합니다. 파이썬 3.6은 2016년 12월 23일에 출시되었습니다. 전체 변경 목록은 changelog [https://docs.python.org/3.6/whatsnew/changelog.html]를 참조하십시오.

더 보기

PEP 494 [https://peps.python.org/pep-0494/] - 파이썬 3.6 출시 일정

요약 – 배포 주요 사항

새로운 문법 기능:

PEP 498, 포맷 문자열 리터럴.

PEP 515, 숫자 리터럴의 밑줄.

PEP 526, 변수 어노테이션 문법.

PEP 525, 비동기 제너레이터.

PEP 530: 비동기 컴프리헨션.

새로운 라이브러리 모듈:

secrets: PEP 506 – 표준 라이브러리에 secret 모듈 추가.

CPython 구현 개선:

dict 형은 Raymond Hettinger의 제안 [https://mail.python.org/pipermail/python-dev/2012-December/123028.html]에 기반한 더욱더 간결한 표현을 사용하도록 재구현되었으며 PyPy 딕셔너리 구현 [https://morepypy.blogspot.com/2015/01/faster-more-memory-efficient-and-more.html]과 유사합니다. 이로 인해 파이썬 3.5와 비교할 때 딕셔너리가 20%에서 25% 적은 메모리를 사용하게 되었습니다.

새 프로토콜로 클래스 생성의 사용자 정의가 단순화되었습니다.

클래스 어트리뷰트 정의 순서는 이제 보존됩니다.

**kwargs의 요소 순서는 이제 키워드 인자가 함수에 전달된 순서에 해당합니다.

DTrace와 SystemTap 프로브 지원이 추가되었습니다.

이제 새로운 PYTHONMALLOC 환경 변수를 사용하여 인터프리터 메모리 할당과 액세스 에러를 디버깅 할 수 있습니다.

표준 라이브러리 대폭 개선:

asyncio 모듈은 새로운 기능, 상당한 사용성 및 성능 향상, 상당한 양의 버그 수정을 받았습니다. 파이썬 3.6부터 asyncio 모듈은 더는 잠정적이지 않으며 해당 API는 안정적인 것으로 간주합니다.

경로류 객체를 지원하기 위해 새로운 파일 시스템 경로 프로토콜이 구현되었습니다. 경로에서 작동하는 모든 표준 라이브러리 함수가 새 프로토콜과 함께 작동하도록 갱신되었습니다.

datetime 모듈은 현지 시간 명확성에 대한 지원을 얻었습니다.

typing 모듈은 여러 개선을 받았습니다.

tracemalloc 모듈은 크게 다시 작업 되었으며 이제 ResourceWarning에 대해 더 나은 출력을 제공하고 메모리 할당 에러에 대한 더 나은 진단을 제공하는 데 사용됩니다. 자세한 내용은 PYTHONMALLOC 섹션을 참조하십시오.

보안 향상:

새로운 secrets 모듈이 추가되어 계정 인증, 토큰 등과 같은 비밀 관리에 적합한 암호화 된 강력한 의사 난수 생성을 단순화합니다.

리눅스에서, os.urandom()은 이제 보안을 강화하기 위해 시스템 urandom 엔트로피 풀이 초기화될 때까지 블록합니다. 근거는 PEP 524 [https://peps.python.org/pep-0524/]를 참조하십시오.

hashlib와 ssl 모듈은 이제 OpenSSL 1.1.0을 지원합니다.

ssl 모듈의 기본 설정과 기능 집합이 개선되었습니다.

hashlib 모듈은 BLAKE2, SHA-3 및 SHAKE 해시 알고리즘과 scrypt() 키 파생 함수에 대한 지원을 받았습니다.

윈도우 개선:

PEP 528과 PEP 529, 윈도우 파일 시스템과 콘솔 인코딩이 UTF-8로 변경되었습니다.

py.exe 런처는 대화식으로 사용할 때 사용자가 버전을 지정하지 않을 때 (명령 줄 인자나 구성 파일을 통해) 더는 파이썬 3보다 파이썬 2를 선호하지 않습니다. 셔뱅 줄의 처리는 변경되지 않았습니다 - 이 경우 “python”은 파이썬 2를 나타냅니다.

python.exe와 pythonw.exe는 긴 경로 인식으로 표시되어서, 260자 경로 제한이 더는 적용되지 않을 수 있음을 뜻합니다. 자세한 내용은 MAX_PATH 제한 제거를 참조하십시오.

A ._pth file can be added to force isolated mode and fully specify all search paths to avoid registry and environment lookup. See the documentation for more information.

A python36.zip file now works as a landmark to infer PYTHONHOME. See the documentation for more information.

새로운 기능

PEP 498: 포맷 문자열 리터럴

PEP 498 [https://peps.python.org/pep-0498/]은 새로운 종류의 문자열 리터럴 f-문자열(f-strings), 또는 포맷 문자열 리터럴을 도입합니다.

포맷 문자열 리터럴은 'f'를 접두어로 사용하고 str.format()에서 허용하는 포맷 문자열과 유사합니다. 중괄호로 둘러싸인 치환 필드가 포함됩니다. 치환 필드는 실행 시간에 평가된 다음 format() 프로토콜을 사용하여 포맷되는 표현식입니다:

>>> name = "Fred"
>>> f"He said his name is {name}."
'He said his name is Fred.'
>>> width = 10
>>> precision = 4
>>> value = decimal.Decimal("12.34567")
>>> f"result: {value:{width}.{precision}}"  # nested fields
'result:      12.35'

더 보기

PEP 498 [https://peps.python.org/pep-0498/] – 리터럴 문자열 보간.

Eric V. Smith가 작성하고 구현한 PEP.

기능 설명서.

PEP 526: 변수 어노테이션 문법

PEP 484 [https://peps.python.org/pep-0484/]는 함수 매개 변수의 형 어노테이션, 일명 형 힌트에 대한 표준을 도입했습니다. 이 PEP는 클래스 변수와 인스턴스 변수를 포함한 변수 형에 어노테이트하기 위해 파이썬에 구문을 추가합니다:

primes: List[int] = []

captain: str  # Note: no initial value!

class Starship:
    stats: Dict[str, int] = {}

함수 어노테이션과 마찬가지로, 파이썬 인터프리터는 변수 어노테이션에 특별한 의미를 부여하지 않고 클래스나 모듈의 __annotations__ 어트리뷰트에 저장하기만 합니다.

정적으로 타이핑된 언어의 변수 선언과 달리, 어노테이션 문법의 목표는 추상 구문 트리와 __annotations__ 어트리뷰트를 통해 제삼자 도구와 라이브러리를 위해 구조화된 형 메타 데이터를 쉽게 지정할 방법을 제공하는 것입니다.

더 보기

PEP 526 [https://peps.python.org/pep-0526/] – 변수 어노테이션 문법.

Ryan Gonzalez, Philip House, Ivan Levkivskyi, Lisa Roach 및 Guido van Rossum이 작성한 PEP. Ivan Levkivskyi가 구현했습니다.

Tools that use or will use the new syntax: mypy [https://www.mypy-lang.org/], pytype [https://github.com/google/pytype], PyCharm, etc.

PEP 515: 숫자 리터럴의 밑줄

PEP 515 [https://peps.python.org/pep-0515/]는 가독성을 높이기 위해 숫자 리터럴에 밑줄을 사용하는 기능을 추가합니다. 예를 들면:

>>> 1_000_000_000_000_000
1000000000000000
>>> 0x_FF_FF_FF_FF
4294967295

숫자 사이와 진수 지정자(base specifier) 뒤에 단일 밑줄이 허용됩니다. 선행, 후행 또는 여러 밑줄이 연속해서 나오는 것은 허용되지 않습니다.

The string formatting language also now has support for the '_' option to signal the use of an underscore for a thousands separator for floating-point presentation types and for integer presentation type 'd'. For integer presentation types 'b', 'o', 'x', and 'X', underscores will be inserted every 4 digits:

>>> '{:_}'.format(1000000)
'1_000_000'
>>> '{:_x}'.format(0xFFFFFFFF)
'ffff_ffff'

더 보기

PEP 515 [https://peps.python.org/pep-0515/] – 숫자 리터럴의 밑줄

Georg Brandl과 Serhiy Storchaka가 작성한 PEP.

PEP 525: 비동기 제너레이터

PEP 492 [https://peps.python.org/pep-0492/]는 파이썬 3.5에 네이티브 코루틴과 async / await 구문에 대한 지원을 도입했습니다. 파이썬 3.5 구현의 주목할만한 제한은 같은 함수 본문에서 await와 yield를 사용할 수 없다는 것입니다. 파이썬 3.6에서는 이 제한이 해제되어 비동기 제너레이터(asynchronous generators)를 정의할 수 있습니다:

async def ticker(delay, to):
    """Yield numbers from 0 to *to* every *delay* seconds."""
    for i in range(to):
        yield i
        await asyncio.sleep(delay)

새로운 문법은 더 빠르고 간결한 코드를 허용합니다.

더 보기

PEP 525 [https://peps.python.org/pep-0525/] – 비동기 제너레이터

Yury Selivanov가 작성하고 구현한 PEP.

PEP 530: 비동기 컴프리헨션

PEP 530 [https://peps.python.org/pep-0530/]은 리스트, 집합, 딕셔너리 컴프리헨션과 제너레이터 표현식에서 async for 사용에 대한 지원을 추가합니다:

result = [i async for i in aiter() if i % 2]

또한, await 표현식은 모든 종류의 컴프리헨션에서 지원됩니다:

result = [await fun() for fun in funcs if await condition()]

더 보기

PEP 530 [https://peps.python.org/pep-0530/] – 비동기 컴프리헨션

Yury Selivanov가 작성하고 구현한 PEP.

PEP 487: 더 간단한 클래스 생성 사용자 정의

이제 메타 클래스를 사용하지 않고도 서브 클래스 생성을 사용자 정의할 수 있습니다. 새 서브 클래스가 만들어질 때마다 새 __init_subclass__ 클래스 메서드가 베이스 클래스에서 호출됩니다:

class PluginBase:
    subclasses = []

    def __init_subclass__(cls, **kwargs):
        super().__init_subclass__(**kwargs)
        cls.subclasses.append(cls)

class Plugin1(PluginBase):
    pass

class Plugin2(PluginBase):
    pass

인자가 없는 super() 호출이 __init_subclass__() 구현에서 올바르게 작동하도록 하기 위해, 사용자 정의 메타 클래스에서 새 __classcell__ 이름 공간 항목이 type.__new__로 전파되도록 해야 합니다 (클래스 객체 만들기에 설명되었듯이).

더 보기

PEP 487 [https://peps.python.org/pep-0487/] – 더 간단한 클래스 생성 사용자 정의

Martin Teichmann이 작성하고 구현한 PEP.

기능 설명서

PEP 487: 디스크립터 프로토콜 향상

PEP 487 [https://peps.python.org/pep-0487/]은 새로운 선택적 __set_name__() 메서드를 포함하도록 디스크립터 프로토콜을 확장합니다. 새 클래스가 정의될 때마다, 정의에 포함된 모든 디스크립터에 대해 새 메서드가 호출되어, 정의되는 클래스에 대한 참조와 클래스 이름 공간 내에서 디스크립터에 지정된 이름을 제공합니다. 즉, 디스크립터의 인스턴스는 이제 소유자 클래스에 있는 디스크립터의 어트리뷰트 이름을 알 수 있습니다:

class IntField:
    def __get__(self, instance, owner):
        return instance.__dict__[self.name]

    def __set__(self, instance, value):
        if not isinstance(value, int):
            raise ValueError(f'expecting integer in {self.name}')
        instance.__dict__[self.name] = value

    # this is the new initializer:
    def __set_name__(self, owner, name):
        self.name = name

class Model:
    int_field = IntField()

더 보기

PEP 487 [https://peps.python.org/pep-0487/] – 더 간단한 클래스 생성 사용자 정의

Martin Teichmann이 작성하고 구현한 PEP.

기능 설명서

PEP 519: 파일 시스템 경로 프로토콜 추가

파일 시스템 경로는 역사적으로 str이나 bytes 객체로 표현되었습니다. 이로 인해 파일 시스템 경로에서 작동하는 코드를 작성하는 사람들은 이러한 객체가 두 형 중 하나일 뿐이라고 가정합니다 (파일 기술자를 나타내는 int는 파일 경로가 아니기 때문에 고려하지 않습니다). 불행히도 이러한 가정은 pathlib와 같은 파일 시스템 경로의 대체 객체 표현이 파이썬의 표준 라이브러리를 포함하여 기존 코드와 함께 작동하지 못하게 합니다.

이 상황을 해결하기 위해, os.PathLike으로 표현되는 새 인터페이스가 정의되었습니다. __fspath__() 메서드를 구현하면, 객체가 경로를 나타낸다는 신호를 보내는 것입니다. 그런 다음 객체는 파일 시스템 경로의 저수준 표현을 str이나 bytes 객체로 제공할 수 있습니다. 이것은 os.PathLike을 구현하거나 파일 시스템 경로를 나타내는 str나 bytes 객체면 객체를 경로류로 간주함을 뜻합니다. 코드는 os.fspath(), os.fsdecode() 또는 os.fsencode()를 사용하여 경로류 객체의 str 및/또는 bytes 표현을 명시적으로 얻을 수 있습니다.

내장 open() 함수는 os와 os.path 모듈의 모든 관련 함수와 표준 라이브러리의 대부분의 다른 함수와 클래스와 마찬가지로, os.PathLike 객체를 받아들이도록 갱신되었습니다. os.DirEntry 클래스와 pathlib의 관련 클래스도 os.PathLike을 구현하도록 갱신되었습니다.

기대하는 것은 파일 시스템 경로에서 작동하는 기반 함수들을 갱신하면 코드 변경 없이, 혹은 최소한의 변경만으로도 (예를 들어 경로류 객체에 대한 연산 전에 코드 시작 부분에서 os.fspath()를 호출하기), 제삼자 코드가 모든 경로류 객체를 묵시적으로 지원하게 되는 것입니다.

다음은 새 인터페이스를 사용하여 pathlib.Path를 기존 코드로보다 쉽고 투명하게 사용할 수 있는 방법에 대한 몇 가지 예입니다:

>>> import pathlib
>>> with open(pathlib.Path("README")) as f:
...     contents = f.read()
...
>>> import os.path
>>> os.path.splitext(pathlib.Path("some_file.txt"))
('some_file', '.txt')
>>> os.path.join("/a/b", pathlib.Path("c"))
'/a/b/c'
>>> import os
>>> os.fspath(pathlib.Path("some_file.txt"))
'some_file.txt'

(Implemented by Brett Cannon, Ethan Furman, Dusty Phillips, and Jelle Zijlstra.)

더 보기

PEP 519 [https://peps.python.org/pep-0519/] – 파일 시스템 경로 프로토콜 추가

Brett Cannon과 Koos Zevenhoven이 작성한 PEP.

PEP 495: 현지 시간 명확성

대부분의 세계 위치에서, 현지 시계가 뒤로 이동하는 시간이 있었고 앞으로도 있을 것입니다. 이 시간에는, 현지 시계가 같은 날에 같은 시간을 두 번 표시하는 간격이 도입되었습니다. 이러한 상황에서, 현지 시계에 표시되는 (또는 파이썬 datetime 인스턴스에 저장된) 정보는 특정 시점을 식별하기에 충분하지 않습니다.

PEP 495 [https://peps.python.org/pep-0495/]는 datetime.datetime과 datetime.time 클래스의 인스턴스에 새로운 fold 어트리뷰트를 추가하여 현지 시간이 같은 두 순간을 구별합니다:

>>> u0 = datetime(2016, 11, 6, 4, tzinfo=timezone.utc)
>>> for i in range(4):
...     u = u0 + i*HOUR
...     t = u.astimezone(Eastern)
...     print(u.time(), 'UTC =', t.time(), t.tzname(), t.fold)
...
04:00:00 UTC = 00:00:00 EDT 0
05:00:00 UTC = 01:00:00 EDT 0
06:00:00 UTC = 01:00:00 EST 1
07:00:00 UTC = 02:00:00 EST 0

fold 어트리뷰트의 값은 모호한 경우의 두 번째 (시간순으로) 순간을 나타내는 인스턴스를 제외한 모든 인스턴스에 대해 0 값을 갖습니다.

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PEP 495 [https://peps.python.org/pep-0495/] – 현지 시간 명확성

Alexander Belopolsky와 Tim Peters가 작성하고 Alexander Belopolsky가 구현한 PEP.

PEP 529: 윈도우 파일 시스템 인코딩을 UTF-8로 변경

파일 시스템 경로를 나타내는 것은 bytes가 아닌 str(유니코드)로 수행하는 것이 가장 좋습니다. 그러나, bytes 사용이 충분하고 올바른 경우가 있습니다.

Prior to Python 3.6, data loss could result when using bytes paths on Windows. With this change, using bytes to represent paths is now supported on Windows, provided those bytes are encoded with the encoding returned by sys.getfilesystemencoding(), which now defaults to 'utf-8'.

Applications that do not use str to represent paths should use os.fsencode() and os.fsdecode() to ensure their bytes are correctly encoded. To revert to the previous behaviour, set PYTHONLEGACYWINDOWSFSENCODING or call sys._enablelegacywindowsfsencoding().

필요한 코드 수정에 대한 자세한 정보와 논의는 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오.

PEP 528: 윈도우 콘솔 인코딩을 UTF-8로 변경

윈도우의 기본 콘솔은 이제 모든 유니코드 문자를 허용하고 파이썬 코드에 올바르게 읽힌 str 객체를 제공합니다. sys.stdin, sys.stdout 및 sys.stderr은 이제 utf-8 인코딩으로 기본 설정됩니다.

이 변경은 대화 형 콘솔을 사용할 때만 적용되며, 파일이나 파이프를 리디렉션 할 때는 적용되지 않습니다. 대화식 콘솔 사용 시에 이전 동작으로 되돌리려면, PYTHONLEGACYWINDOWSSTDIO를 설정하십시오.

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PEP 528 [https://peps.python.org/pep-0528/] – 윈도우 콘솔 인코딩을 UTF-8로 변경

Steve Dower가 작성하고 구현한 PEP.

PEP 520: 클래스 어트리뷰트 정의 순서 유지

Attributes in a class definition body have a natural ordering: the same order in which the names appear in the source. This order is now preserved in the new class’s __dict__ attribute.

또한, 유효한 기본 클래스 실행 이름 공간(type.__prepare__()에서 반환되는 것)은 이제 삽입 순서 보존 매핑입니다.

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PEP 520 [https://peps.python.org/pep-0520/] – 클래스 어트리뷰트 정의 순서 유지

Eric Snow가 작성하고 구현한 PEP.

PEP 468: 키워드 인자 순서 유지

함수 서명의 **kwargs는 이제 삽입 순서 보존 매핑임이 보장됩니다.

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PEP 468 [https://peps.python.org/pep-0468/] – 키워드 인자 순서 유지

Eric Snow가 작성하고 구현한 PEP.

새로운 dict 구현

dict 형은 이제 PyPy에서 처음 구현된 [https://morepypy.blogspot.com/2015/01/faster-more-memory-efficient-and-more.html] Raymond Hettinger의 제안 [https://mail.python.org/pipermail/python-dev/2012-December/123028.html]에 기반한 “간결한” 표현을 사용합니다. 새로운 dict()의 메모리 사용량은 파이썬 3.5에 비해 20%에서 25% 더 적습니다.

이 새로운 구현의 순서 보존 측면은 구현 세부 사항으로 간주하며 이에 의존해서는 안 됩니다 (향후에 변경될 수 있지만, 현재와 미래의 모든 파이썬 구현에 대해 순서 보존 의미 체계를 의무화하도록 언어 명세를 변경하기 전에 몇 번의 릴리스에서 이 새로운 dict 구현을 언어에 포함하는 것이 바람직합니다; 이것은 또한 무작위 이터레이션 순서가 여전히 유효한 언어의 이전 버전과의 과거 호환성을 유지하는 데 도움이 됩니다, 예를 들어 파이썬 3.5).

(Contributed by INADA Naoki in bpo-27350 [https://bugs.python.org/issue?@action=redirect&bpo=27350]. 원래 Raymond Hettinger가 제안한 [https://mail.python.org/pipermail/python-dev/2012-December/123028.html] 아이디어.)

PEP 523: CPython에 프레임 평가 API 추가

파이썬은 코드 실행 방법을 사용자 정의하기 위한 광범위한 지원을 제공하지만, 빠진 한 가지는 프레임 객체를 평가하는 것입니다. 파이썬에서 프레임 평가를 가로채는 방법을 원한다면 정의된 함수에 대한 함수 포인터를 직접 조작하지 않고는 방법이 없었습니다.

PEP 523 [https://peps.python.org/pep-0523/]은 프레임 평가를 C 수준에서 끼워 넣을 수 있도록 하는 API를 제공하여 이를 바꿉니다. 이를 통해 디버거와 JIT과 같은 도구가 파이썬 코드 실행이 시작되기 전에 프레임 평가를 가로챌 수 있습니다. 이를 통해 파이썬 코드의 대체 평가 구현, 추적 프레임 평가 등이 가능해집니다.

이 API는 제한된 C API의 일부가 아니며 이 API의 사용이 제한적일 것으로 기대하고, 매우 선별된 저수준 사용 사례에만 적용 가능함을 알리기 위해 비공개로 표시됩니다. API의 의미는 필요에 따라 파이썬과 함께 변경됩니다.

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PEP 523 [https://peps.python.org/pep-0523/] – CPython에 프레임 평가 API 추가

Brett Cannon과 Dino Viehland가 작성한 PEP.

PYTHONMALLOC 환경 변수

새로운 PYTHONMALLOC 환경 변수를 사용하면 파이썬 메모리 할당자를 설정하고 디버그 훅을 설치할 수 있습니다.

이제 PYTHONMALLOC=debug를 사용하여 릴리스 모드로 컴파일된 파이썬의 파이썬 메모리 할당자에 디버그 훅을 설치할 수 있습니다. 디버그 훅의 효과:

새로 할당된 메모리는 0xCB 바이트로 채워집니다

해제된 메모리는 0xDB 바이트로 채워집니다

파이썬 메모리 할당자 API 위반을 감지합니다. 예를 들어, PyMem_Malloc()에 의해 할당된 메모리 블록에 대해 호출된 PyObject_Free().

버퍼 시작 앞에 쓰기를 감지합니다 (버퍼 언더플로)

버퍼 끝 뒤에 쓰기를 감지합니다 (버퍼 오버플로)

Check that the GIL is held when allocator functions of PYMEM_DOMAIN_OBJ (ex: PyObject_Malloc()) and PYMEM_DOMAIN_MEM (ex: PyMem_Malloc()) domains are called.

GIL을 잡았는지 확인하는 것도 파이썬 3.6의 새로운 기능입니다.

파이썬 메모리 할당자에 대한 디버그 훅은 PyMem_SetupDebugHooks() 함수를 참조하십시오.

이제 PYTHONMALLOC=malloc을 사용해서 모든 파이썬 메모리 할당에 대해 C 라이브러리의 malloc() 할당자를 강제로 사용하게 할 수도 있습니다. 이것은 릴리스 모드로 컴파일된 파이썬에 Valgrind와 같은 외부 메모리 디버거를 사용할 때 유용합니다.

에러 시, 파이썬 메모리 할당자의 디버그 훅은 이제 tracemalloc 모듈을 사용하여 메모리 블록이 할당된 트레이스백을 가져옵니다.

python3.6 -X tracemalloc=5(트레이스에 5개 프레임을 저장합니다)를 사용하는 버퍼 오버플로로 인한 치명적인 에러의 예:

Debug memory block at address p=0x7fbcd41666f8: API 'o'
    4 bytes originally requested
    The 7 pad bytes at p-7 are FORBIDDENBYTE, as expected.
    The 8 pad bytes at tail=0x7fbcd41666fc are not all FORBIDDENBYTE (0xfb):
        at tail+0: 0x02 *** OUCH
        at tail+1: 0xfb
        at tail+2: 0xfb
        at tail+3: 0xfb
        at tail+4: 0xfb
        at tail+5: 0xfb
        at tail+6: 0xfb
        at tail+7: 0xfb
    The block was made by call #1233329 to debug malloc/realloc.
    Data at p: 1a 2b 30 00

Memory block allocated at (most recent call first):
  File "test/test_bytes.py", line 323
  File "unittest/case.py", line 600
  File "unittest/case.py", line 648
  File "unittest/suite.py", line 122
  File "unittest/suite.py", line 84

Fatal Python error: bad trailing pad byte

Current thread 0x00007fbcdbd32700 (most recent call first):
  File "test/test_bytes.py", line 323 in test_hex
  File "unittest/case.py", line 600 in run
  File "unittest/case.py", line 648 in __call__
  File "unittest/suite.py", line 122 in run
  File "unittest/suite.py", line 84 in __call__
  File "unittest/suite.py", line 122 in run
  File "unittest/suite.py", line 84 in __call__
  ...

(Contributed by Victor Stinner in bpo-26516 [https://bugs.python.org/issue?@action=redirect&bpo=26516] and bpo-26564 [https://bugs.python.org/issue?@action=redirect&bpo=26564].)

DTrace와 SystemTap 프로브 지원

이제 파이썬은 인터프리터에서 다음 이벤트에 대한 정적 마커를 활성화하는 --with-dtrace로 빌드 할 수 있습니다:

함수 호출/반환

가비지 수거 시작/완료

실행된 코드 줄.

This can be used to instrument running interpreters in production, without the need to recompile specific debug builds or providing application-specific profiling/debugging code.

자세한 내용은 DTrace와 SystemTap으로 CPython 계측하기에 있습니다.

현재 구현은 리눅스와 macOS에서 테스트되었습니다. 향후 추가 마커가 추가될 수 있습니다.

(Contributed by Łukasz Langa in bpo-21590 [https://bugs.python.org/issue?@action=redirect&bpo=21590], based on patches by Jesús Cea Avión, David Malcolm, and Nikhil Benesch.)

기타 언어 변경

핵심 파이썬 언어에 대한 몇 가지 작은 변경 사항은 다음과 같습니다:

global이나 nonlocal 문은 이제 같은 스코프에서 영향을 받는 이름을 처음 사용하기 전에 텍스트로 나타나야 합니다. 이전에는 SyntaxWarning이었습니다.

이제 해당 연산을 사용할 수 없음을 나타내기 위해 특수 메서드를 None으로 설정할 수 있습니다. 예를 들어, 클래스가 __iter__()를 None으로 설정하면, 해당 클래스는 이터러블이 아닙니다. (Contributed by Andrew Barnert and Ivan Levkivskyi in bpo-25958 [https://bugs.python.org/issue?@action=redirect&bpo=25958].)

반복되는 트레이스백 줄의 긴 시퀀스는 이제 "[Previous line repeated {count} more times]"로 축약됩니다 (예는 traceback 을 참조하십시오). (Contributed by Emanuel Barry in bpo-26823 [https://bugs.python.org/issue?@action=redirect&bpo=26823].)

임포트는 이제 모듈을 찾을 수 없을 때 새로운 예외 ModuleNotFoundError(ImportError의 서브 클래스)를 발생시킵니다. 현재 (try-except에서) ImportError를 확인하는 코드는 계속 작동합니다. (Contributed by Eric Snow in bpo-15767 [https://bugs.python.org/issue?@action=redirect&bpo=15767].)

인자가 없는 super()에 의존하는 클래스 메서드는 이제 클래스 생성 중에 메타 클래스 메서드에서 호출될 때 올바르게 작동합니다. (Contributed by Martin Teichmann in bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722].)

새로운 모듈

secrets

새로운 secrets 모듈의 주요 목적은 계정 인증, 토큰 등과 같은 비밀 관리에 적합한 암호학적으로 강력한 의사 난수 값을 신뢰성 있게 생성할 수 있는 확실한 방법을 제공하는 것입니다.

경고

Note that the pseudo-random generators in the random module should NOT be used for security purposes. Use secrets on Python 3.6+ and os.urandom() on Python 3.5 and earlier.

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PEP 506 [https://peps.python.org/pep-0506/] – 표준 라이브러리에 비밀 모듈 추가

Steven D’Aprano 가 작성하고 구현한 PEP.

개선된 모듈

array

array.array의 소진된 이터레이터는 이제 이터레이트 되는 배열이 확장된 경우에도 소진된 상태로 유지됩니다. 이것은 다른 가변 시퀀스의 동작과 일치합니다.

Contributed by Serhiy Storchaka in bpo-26492 [https://bugs.python.org/issue?@action=redirect&bpo=26492].

ast

새로운 ast.Constant AST 노드가 추가되었습니다. 상수 폴딩을 위해 외부 AST 최적화기에서 사용할 수 있습니다.

Contributed by Victor Stinner in bpo-26146 [https://bugs.python.org/issue?@action=redirect&bpo=26146].

asyncio

파이썬 3.6부터 asyncio 모듈은 더는 잠정적이 아니며 해당 API는 안정적인 것으로 간주합니다.

파이썬 3.5.0 이후 asyncio 모듈의 주목할만한 변경 사항 (잠정적 상태로 인해 모두 3.5.x로 역 이식되었습니다):

get_event_loop() 함수는 코루틴과 콜백에서 호출될 때 항상 현재 실행 중인 루프를 반환하도록 변경되었습니다. (Contributed by Yury Selivanov in bpo-28613 [https://bugs.python.org/issue?@action=redirect&bpo=28613].)

ensure_future() 함수와 이를 사용하는 모든 함수(가령 loop.run_until_complete())는 이제 모든 종류의 어웨이터블 객체를 받아들입니다. (Contributed by Yury Selivanov.)

다른 스레드의 이벤트 루프에 코루틴을 제출하는 새로운 run_coroutine_threadsafe() 함수. (Contributed by Vincent Michel.)

트랜스포트가 닫히고 있거나 닫혔는지 확인하는 새로운 Transport.is_closing() 메서드. (Contributed by Yury Selivanov.)

loop.create_server() 메서드는 이제 호스트 리스트를 받아들일 수 있습니다. (Contributed by Yann Sionneau.)

Future 객체를 만드는 새로운 loop.create_future() 메서드. 이를 통해 uvloop [https://github.com/MagicStack/uvloop]와 같은 대체 이벤트 루프 구현이 더 빠른 asyncio.Future 구현을 제공할 수 있습니다. (Contributed by Yury Selivanov in bpo-27041 [https://bugs.python.org/issue?@action=redirect&bpo=27041].)

현재 예외 처리기를 가져오는 새로운 loop.get_exception_handler() 메서드. (Contributed by Yury Selivanov in bpo-27040 [https://bugs.python.org/issue?@action=redirect&bpo=27040].)

구분자 바이트 시퀀스가 나타날 때까지 스트림에서 데이터를 읽는 새로운 StreamReader.readuntil() 메서드. (Contributed by Mark Korenberg.)

StreamReader.readexactly()의 성능이 향상되었습니다. (Contributed by Mark Korenberg in bpo-28370 [https://bugs.python.org/issue?@action=redirect&bpo=28370].)

loop.getaddrinfo() 메서드는 주소가 이미 결정되었으면 시스템 getaddrinfo 함수를 호출하지 않도록 최적화되었습니다. (Contributed by A. Jesse Jiryu Davis.)

현재 이터레이션 직후 루프를 중지하도록 loop.stop() 메서드가 변경되었습니다. 마지막 이터레이션의 결과로 예약된 모든 새 콜백은 버려집니다. (Contributed by Guido van Rossum in bpo-25593 [https://bugs.python.org/issue?@action=redirect&bpo=25593].)

Future.set_exception은 이제 StopIteration 예외의 인스턴스가 전달될 때 TypeError를 발생시킵니다. (Contributed by Chris Angelico in bpo-26221 [https://bugs.python.org/issue?@action=redirect&bpo=26221].)

asyncio 외부의 연결을 받아들이지만 이를 처리하기 위해 asyncio를 사용하는 서버에서 사용할 새로운 loop.connect_accepted_socket() 메서드. (Contributed by Jim Fulton in bpo-27392 [https://bugs.python.org/issue?@action=redirect&bpo=27392].)

TCP_NODELAY 플래그는 이제 기본적으로 모든 TCP 트랜스포트에 대해 설정됩니다. (Contributed by Yury Selivanov in bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456].)

루프를 닫기 전에 계류 중인 비동기 제너레이터를 제대로 닫는 새로운 loop.shutdown_asyncgens(). (Contributed by Yury Selivanov in bpo-28003 [https://bugs.python.org/issue?@action=redirect&bpo=28003].)

Future와 Task 클래스는 이제 asyncio 코드를 최대 30% 더 빠르게 만드는 최적화된 C 구현을 갖습니다. (Contributed by Yury Selivanov and INADA Naoki in bpo-26081 [https://bugs.python.org/issue?@action=redirect&bpo=26081] and bpo-28544 [https://bugs.python.org/issue?@action=redirect&bpo=28544].)

Binascii

b2a_base64() 함수는 이제 반환 값에 줄 넘김 문자를 추가할지를 제어하기 위해 선택적 newline 키워드 인자를 받아들입니다. (Contributed by Victor Stinner in bpo-25357 [https://bugs.python.org/issue?@action=redirect&bpo=25357].)

cmath

새로운 cmath.tau (τ) 상수가 추가되었습니다. (Contributed by Lisa Roach in bpo-12345 [https://bugs.python.org/issue?@action=redirect&bpo=12345], see PEP 628 [https://peps.python.org/pep-0628/] for details.)

새로운 상수: math.inf와 math.nan과 일치하는 cmath.inf와 cmath.nan, 그리고 복소수 repr에서 사용하는 형식과 일치하는 cmath.infj와 cmath.nanj. (Contributed by Mark Dickinson in bpo-23229 [https://bugs.python.org/issue?@action=redirect&bpo=23229].)

collections

새로운 Collection 추상 베이스 클래스가 추가되어 길이가 있는 이터러블 컨테이너 클래스를 나타냅니다. (Contributed by Ivan Levkivskyi, docs by Neil Girdhar in bpo-27598 [https://bugs.python.org/issue?@action=redirect&bpo=27598].)

새로운 Reversible 추상 베이스 클래스는 __reversed__() 메서드도 제공하는 이터러블 클래스를 나타냅니다. (Contributed by Ivan Levkivskyi in bpo-25987 [https://bugs.python.org/issue?@action=redirect&bpo=25987].)

새로운 AsyncGenerator 추상 베이스 클래스는 비동기 제너레이터를 나타냅니다. (Contributed by Yury Selivanov in bpo-28720 [https://bugs.python.org/issue?@action=redirect&bpo=28720].)

The namedtuple() function now accepts an optional keyword argument module, which, when specified, is used for the __module__ attribute of the returned named tuple class. (Contributed by Raymond Hettinger in bpo-17941 [https://bugs.python.org/issue?@action=redirect&bpo=17941].)

namedtuple()에 대한 verbose와 rename 인자는 이제 키워드 전용입니다. (Contributed by Raymond Hettinger in bpo-25628 [https://bugs.python.org/issue?@action=redirect&bpo=25628].)

이제 재귀 collections.deque 인스턴스를 피클 할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-26482 [https://bugs.python.org/issue?@action=redirect&bpo=26482].)

concurrent.futures

ThreadPoolExecutor 클래스 생성자는 이제 선택적 thread_name_prefix 인자를 받아들여 풀이 만든 스레드의 이름을 사용자 정의할 수 있습니다. (Contributed by Gregory P. Smith in bpo-27664 [https://bugs.python.org/issue?@action=redirect&bpo=27664].)

contextlib

The contextlib.AbstractContextManager class has been added to provide an abstract base class for context managers. It provides a sensible default implementation for __enter__() which returns self and leaves __exit__() an abstract method. A matching class has been added to the typing module as typing.ContextManager. (Contributed by Brett Cannon in bpo-25609 [https://bugs.python.org/issue?@action=redirect&bpo=25609].)

datetime

datetime과 time 클래스에는 필요할 때 현지 시간을 명확히 하는 데 사용되는 새로운 fold 어트리뷰트를 갖습니다. datetime의 많은 함수가 현지 시간 명확성을 지원하도록 갱신되었습니다. 자세한 내용은 현지 시간 명확성 섹션을 참조하십시오. (Contributed by Alexander Belopolsky in bpo-24773 [https://bugs.python.org/issue?@action=redirect&bpo=24773].)

datetime.strftime()과 date.strftime() 메서드는 이제 ISO 8601 날짜 지시자 %G, %u 및 %V를 지원합니다. (Contributed by Ashley Anderson in bpo-12006 [https://bugs.python.org/issue?@action=redirect&bpo=12006].)

datetime.isoformat() 함수는 이제 포함할 시간 값의 추가 구성 요소 수를 지정하는 선택적 timespec 인자를 받아들입니다. (Contributed by Alessandro Cucci and Alexander Belopolsky in bpo-19475 [https://bugs.python.org/issue?@action=redirect&bpo=19475].)

datetime.combine()은 이제 선택적 tzinfo 인자를 받아들입니다. (Contributed by Alexander Belopolsky in bpo-27661 [https://bugs.python.org/issue?@action=redirect&bpo=27661].)

decimal

주어진 Decimal 인스턴스를 분수로 표현하는 정수 쌍 (n, d)를 가장 작은 항과 양의 분모로 반환하는 새로운 Decimal.as_integer_ratio() 메서드:

>>> Decimal('-3.14').as_integer_ratio()
(-157, 50)

(Contributed by Stefan Krah amd Mark Dickinson in bpo-25928 [https://bugs.python.org/issue?@action=redirect&bpo=25928].)

distutils

The default_format attribute has been removed from distutils.command.sdist.sdist and the formats attribute defaults to ['gztar']. Although not anticipated, any code relying on the presence of default_format may need to be adapted. See bpo-27819 [https://bugs.python.org/issue?@action=redirect&bpo=27819] for more details.

email

다양한 생성자에 대한 policy 키워드를 통해 활성화되는 새 이메일 API는 더는 잠정적이 아닙니다. email 설명서는 레거시 API에 대한 이전 설명서를 유지하면서 새 API에 초점을 맞추기 위해 재구성되고 재작성되었습니다. (Contributed by R. David Murray in bpo-24277 [https://bugs.python.org/issue?@action=redirect&bpo=24277].)

이제 email.mime 클래스는 모두 선택적 policy 키워드를 받아들입니다. (Contributed by Berker Peksag in bpo-27331 [https://bugs.python.org/issue?@action=redirect&bpo=27331].)

DecodedGenerator는 이제 policy 키워드를 지원합니다.

구문 분석기가 새 메시지 객체를 만들 때 기본적으로 사용되는 클래스를 제어하는, 새 policy 어트리뷰트 message_factory가 있습니다. email.policy.compat32 정책의 경우 Message이고, 새 정책의 경우 EmailMessage입니다. (Contributed by R. David Murray in bpo-20476 [https://bugs.python.org/issue?@action=redirect&bpo=20476].)

encodings

윈도우에서, CP_OEMCP를 사용하는 'oem' 인코딩을 추가하고, CP_ACP 코드 페이지를 사용하는 기존 'mbcs' 인코딩을 위한 'ansi' 별칭을 추가했습니다. (Contributed by Steve Dower in bpo-27959 [https://bugs.python.org/issue?@action=redirect&bpo=27959].)

enum

enum 모듈에 Flag와 IntFlags라는 두 개의 새로운 열거 베이스 클래스가 추가되었습니다. 둘 다 비트별 연산자를 사용하여 결합할 수 있는 상수를 정의하는 데 사용됩니다. (Contributed by Ethan Furman in bpo-23591 [https://bugs.python.org/issue?@action=redirect&bpo=23591].)

상수에 IntFlags 클래스를 사용하도록 많은 표준 라이브러리 모듈이 갱신되었습니다.

새 enum.auto 값을 사용하여 값을 열거형 멤버에 자동으로 할당할 수 있습니다:

>>> from enum import Enum, auto
>>> class Color(Enum):
...     red = auto()
...     blue = auto()
...     green = auto()
...
>>> list(Color)
[<Color.red: 1>, <Color.blue: 2>, <Color.green: 3>]

faulthandler

윈도우에서, faulthandler 모듈은 이제 윈도우 예외에 대한 처리기를 설치합니다: faulthandler.enable()을 참조하십시오. (Contributed by Victor Stinner in bpo-23848 [https://bugs.python.org/issue?@action=redirect&bpo=23848].)

fileinput

hook_encoded()는 이제 errors 인자를 지원합니다. (Contributed by Joseph Hackman in bpo-25788 [https://bugs.python.org/issue?@action=redirect&bpo=25788].)

hashlib

hashlib는 OpenSSL 1.1.0을 지원합니다. 최소 권장 버전은 1.0.2입니다. (Contributed by Christian Heimes in bpo-26470 [https://bugs.python.org/issue?@action=redirect&bpo=26470].)

BLAKE2 해시 함수가 모듈에 추가되었습니다. blake2b()와 blake2s()는 항상 사용할 수 있으며 BLAKE2의 전체 기능 집합을 지원합니다. (Contributed by Christian Heimes in bpo-26798 [https://bugs.python.org/issue?@action=redirect&bpo=26798] based on code by Dmitry Chestnykh and Samuel Neves. Documentation written by Dmitry Chestnykh.)

SHA-3 해시 함수 sha3_224(), sha3_256(), sha3_384(), sha3_512() 및 SHAKE 해시 함수 shake_128()과 shake_256()이 추가되었습니다. (Contributed by Christian Heimes in bpo-16113 [https://bugs.python.org/issue?@action=redirect&bpo=16113]. Keccak Code Package by Guido Bertoni, Joan Daemen, Michaël Peeters, Gilles Van Assche, and Ronny Van Keer.)

비밀번호 기반 키 파생 함수 scrypt()는 이제 OpenSSL 1.1.0 이상에서 사용할 수 있습니다. (Contributed by Christian Heimes in bpo-27928 [https://bugs.python.org/issue?@action=redirect&bpo=27928].)

http.client

HTTPConnection.request()와 endheaders() 모두 이제 청크 인코딩(chunked encoding) 요청 본문을 지원합니다. (Contributed by Demian Brecht and Rolf Krahl in bpo-12319 [https://bugs.python.org/issue?@action=redirect&bpo=12319].)

idlelib와 IDLE

idlelib 패키지는 IDLE의 모양과 작동을 개선하고 코드를 더 쉽게 이해하고, 테스트하고 개선할 수 있도록 현대화와 리팩토링 되고 있습니다. 특히 리눅스와 맥에서 IDLE을 더 보기 좋게 만드는 부분은 대부분 대화 상자에서 ttk 위젯을 사용하는 것입니다. 결과적으로, IDLE은 더는 tcl/tk 8.4에서 실행되지 않습니다. 이제 tcl/tk 8.5나 8.6이 필요합니다. 둘 중 어느 것이든 최신 릴리스를 실행하는 것이 좋습니다.

‘현대화’에는 idlelib 모듈의 이름 변경과 통합이 포함됩니다. 부분 대문자 이름을 가진 파일의 이름을 바꾸는 것은, 예를 들어 3.0에서 Tkinter와 TkFont를 tkinter와 tkinter.font로 이름을 바꾸는 것과 유사합니다. 결과적으로, 3.5에서 작동했던 idlelib 파일 임포트는 일반적으로 3.6에서 작동하지 않습니다. 최소한 모듈 이름 변경이 필요합니다 (idlelib/README.txt를 참조하십시오). (bpo-24225 [https://bugs.python.org/issue?@action=redirect&bpo=24225]에서 Al Swiegart와 Terry Reedy에 의해 이름이 변경되었습니다. 이후 대부분의 idlelib 패치는 프로세스의 일부였고 앞으로도 그럴 것입니다.)

이에 대한 보상으로, 결과적으로 일부 idlelib 클래스는 더 나은 API와 그를 설명하는 독스트링을 통해 더 쉽게 사용할 수 있습니다. 사용할 수 있으면 추가 유용한 정보가 idlelib에 추가될 것입니다.

3.6.2의 새로운 기능:

자동 완성에 대한 여러 수정. (Contributed by Louie Lu in bpo-15786 [https://bugs.python.org/issue?@action=redirect&bpo=15786].)

3.6.3의 새로운 기능:

모듈 브라우저(File 메뉴에 있는, 예전에는 클래스 브라우저라고 했습니다)는 이제 최상위 함수와 클래스 외에도 중첩된 함수와 클래스를 표시합니다. (Contributed by Guilherme Polo, Cheryl Sabella, and Terry Jan Reedy in bpo-1612262 [https://bugs.python.org/issue?@action=redirect&bpo=1612262].)

이전에 확장으로 구현된 IDLE 기능은 일반 기능으로 다시 구현되었습니다. 설정이 Extension 탭에서 다른 대화 상자 탭으로 이동되었습니다. (Contributed by Charles Wohlganger and Terry Jan Reedy in bpo-27099 [https://bugs.python.org/issue?@action=redirect&bpo=27099].)

설정 대화 상자(Options, Configure IDLE)가 부분적으로 다시 작성되어 모양과 기능이 모두 향상되었습니다. (Contributed by Cheryl Sabella and Terry Jan Reedy in multiple issues.)

3.6.4의 새로운 기능:

이제 글꼴 샘플에는 사용자가 특정 글꼴 선택의 효과를 더 잘 볼 수 있도록 비 라틴 문자 선택이 포함됩니다. (Contributed by Terry Jan Reedy in bpo-13802 [https://bugs.python.org/issue?@action=redirect&bpo=13802].) 샘플은 다른 문자를 포함하도록 편집 할 수 있습니다. (Contributed by Serhiy Storchaka in bpo-31860 [https://bugs.python.org/issue?@action=redirect&bpo=31860].)

3.6.6의 새로운 기능:

편집기 코드 컨텍스트 옵션이 수정되었습니다. 상자는 최대 maxlines까지 모든 컨텍스트 줄을 표시합니다. 컨텍스트 줄을 클릭하면 편집기가 해당 줄로 이동합니다. 사용자 정의 테마의 컨텍스트 색상이 Settings 대화 상자의 Highlights 탭에 추가되었습니다. (Contributed by Cheryl Sabella and Terry Jan Reedy in bpo-33642 [https://bugs.python.org/issue?@action=redirect&bpo=33642], bpo-33768 [https://bugs.python.org/issue?@action=redirect&bpo=33768], and bpo-33679 [https://bugs.python.org/issue?@action=redirect&bpo=33679].)

윈도우에서, 새로운 API 호출은 tk가 DPI에 맞게 확장됨을 윈도우에 알립니다. 윈도우 8.1 이상이나 10에서, 파이썬 바이너리의 DPI 호환성 속성이 변경되지 않고, 96 DPI보다 큰 모니터 해상도를 사용하면, 텍스트와 선이 더 선명해져야 합니다. 그렇지 않으면 효과가 없습니다. (Contributed by Terry Jan Reedy in bpo-33656 [https://bugs.python.org/issue?@action=redirect&bpo=33656].)

3.6.7의 새로운 기능:

N 줄 (기본값은 50) 이상의 출력은 버튼으로 압착됩니다. N은 Settings 대화 상자의 General 페이지에 있는 PyShell 섹션에서 변경할 수 있습니다. 더 적은 (하지만 더 길 수는 있는) 줄은 출력을 마우스 오른쪽 버튼으로 클릭하여 압착할 수 있습니다. 압착된 출력은 버튼을 더블 클릭하여 제자리에서 확장하거나 마우스 오른쪽 버튼으로 버튼을 클릭하여 클립 보드나 별도의 창으로 확장 할 수 있습니다. (Contributed by Tal Einat in bpo-1529353 [https://bugs.python.org/issue?@action=redirect&bpo=1529353].)

importlib

임포트는 이제 모듈을 찾을 수 없을 때 새로운 예외 ModuleNotFoundError(ImportError의 서브 클래스)를 발생시킵니다. 현재 (try-except에서) ImportError를 검사하는 코드는 계속 작동합니다. (Contributed by Eric Snow in bpo-15767 [https://bugs.python.org/issue?@action=redirect&bpo=15767].)

importlib.util.LazyLoader는 이제 래핑 된 로더에서 create_module()을 호출하여, importlib.machinery.BuiltinImporter와 importlib.machinery.ExtensionFileLoader를 importlib.util.LazyLoader와 함께 사용할 수 없는 제한을 제거합니다.

importlib.util.cache_from_source(), importlib.util.source_from_cache() 및 importlib.util.spec_from_file_location()은 이제 경로류 객체를 받아들입니다.

inspect

inspect.signature() 함수는 이제 컴프리헨션과 제너레이터 표현식 스코프에 대해 컴파일러가 생성한 묵시적 .0 매개 변수를 implicit0이라는 위치 전용 매개 변수인 것처럼 보고합니다. (Contributed by Jelle Zijlstra in bpo-19611 [https://bugs.python.org/issue?@action=redirect&bpo=19611].)

파이썬 2.7과 레거시 inspect.getargspec() API에서 업그레이드할 때 코드 변동을 줄이기 위해, 이전에 문서화된 inspect.getfullargspec() 의 폐지가 취소되었습니다. 이 함수는 단일/소스 파이썬 2/3 코드 베이스에 편리하지만, 더 풍부한 inspect.signature() 인터페이스는 새 코드에 권장되는 접근 방식으로 남아 있습니다. (Contributed by Nick Coghlan in bpo-27172 [https://bugs.python.org/issue?@action=redirect&bpo=27172])

json

json.load()와 json.loads()는 이제 바이너리 입력을 지원합니다. 인코딩된 JSON은 UTF-8, UTF-16 또는 UTF-32를 사용하여 표현해야 합니다. (Contributed by Serhiy Storchaka in bpo-17909 [https://bugs.python.org/issue?@action=redirect&bpo=17909].)

logging

새로운 WatchedFileHandler.reopenIfNeeded() 메서드가 추가되어 로그 파일을 다시 열어야 하는지 확인하는 기능이 추가되었습니다. (Contributed by Marian Horban in bpo-24884 [https://bugs.python.org/issue?@action=redirect&bpo=24884].)

math

tau (τ) 상수가 math와 cmath 모듈에 추가되었습니다. (Contributed by Lisa Roach in bpo-12345 [https://bugs.python.org/issue?@action=redirect&bpo=12345], see PEP 628 [https://peps.python.org/pep-0628/] for details.)

multiprocessing

multiprocessing.Manager()에서 반환된 프락시 객체는 이제 중첩될 수 있습니다. (Contributed by Davin Potts in bpo-6766 [https://bugs.python.org/issue?@action=redirect&bpo=6766].)

os

os와 os.path 모듈이 이제 경로류 객체를 지원하는 방법에 대한 자세한 내용은 PEP 519 요약을 참조하십시오.

scandir()은 이제 윈도우에서 bytes 경로를 지원합니다.

새로운 close() 메서드를 사용하면 scandir() 이터레이터를 명시적으로 닫을 수 있습니다. scandir() 이터레이터는 이제 컨텍스트 관리자 프로토콜을 지원합니다. scandir() 이터레이터가 소진되지도 않고 명시적으로 닫히지도 않으면 ResourceWarning이 파괴자에서 방출됩니다. (Contributed by Serhiy Storchaka in bpo-25994 [https://bugs.python.org/issue?@action=redirect&bpo=25994].)

리눅스에서, os.urandom()은 이제 보안을 강화하기 위해 시스템 urandom 엔트로피 풀이 초기화될 때까지 블록합니다. 근거는 PEP 524 [https://peps.python.org/pep-0524/]를 참조하십시오.

리눅스 getrandom() 시스템 호출(무작위 바이트 얻기)이 이제 새로운 os.getrandom() 함수로 노출됩니다. (Contributed by Victor Stinner, part of the PEP 524 [https://peps.python.org/pep-0524/])

pathlib

pathlib는 이제 경로류 객체를 지원합니다. (Contributed by Brett Cannon in bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186].)

자세한 내용은 PEP 519 요약을 참조하십시오.

pdb

Pdb 클래스 생성자에는 .pdbrc 파일을 읽어야 하는지를 제어하는 새로운 선택적 readrc 인자가 있습니다.

pickle

키워드 인자로 호출된 __new__가 필요한 객체는 이제 프로토콜 버전 4보다 오래된 피클 프로토콜을 사용하여 피클 할 수 있습니다. 프로토콜 버전 4는 이미 이 경우를 지원합니다. (Contributed by Serhiy Storchaka in bpo-24164 [https://bugs.python.org/issue?@action=redirect&bpo=24164].)

pickletools

pickletools.dis() now outputs the implicit memo index for the MEMOIZE opcode. (Contributed by Serhiy Storchaka in bpo-25382 [https://bugs.python.org/issue?@action=redirect&bpo=25382].)

pydoc

pydoc 모듈은 MANPAGER 환경 변수를 존중하는 법을 배웠습니다. (Contributed by Matthias Klose in bpo-8637 [https://bugs.python.org/issue?@action=redirect&bpo=8637].)

help()와 pydoc은 이제 사전 순이 아닌 정의된 순서대로 네임드 튜플 필드를 나열할 수 있습니다. (Contributed by Raymond Hettinger in bpo-24879 [https://bugs.python.org/issue?@action=redirect&bpo=24879].)

random

새로운 choices() 함수는 선택적 가중치(weights)를 사용하여 주어진 모집단에서 지정된 크기의 요소 리스트를 반환합니다. (Contributed by Raymond Hettinger in bpo-18844 [https://bugs.python.org/issue?@action=redirect&bpo=18844].)

re

정규식에서 수정자 범위 지원이 추가되었습니다. 예: '(?i:p)ython'은 'python'과 'Python'과 일치하지만, 'PYTHON'은 일치하지 않습니다; '(?i)g(?-i:v)r'는 'GvR'과 'gvr'과 일치하지만, 'GVR'은 일치하지 않습니다. (Contributed by Serhiy Storchaka in bpo-433028 [https://bugs.python.org/issue?@action=redirect&bpo=433028].)

Match 객체 그룹은 group()과 동등한 __getitem__으로 액세스 할 수 있습니다. 따라서 mo['name']은 이제 mo.group('name')과 동등합니다. (Contributed by Eric Smith in bpo-24454 [https://bugs.python.org/issue?@action=redirect&bpo=24454].)

Match 객체는 이제 인덱스류 객체를 그룹 인덱스로 지원합니다. (Contributed by Jeroen Demeyer and Xiang Zhang in bpo-27177 [https://bugs.python.org/issue?@action=redirect&bpo=27177].)

readline

히스토리 리스트에 자동 입력 추가를 활성화하거나 비활성화하는 set_auto_history()를 추가했습니다. (Contributed by Tyler Crompton in bpo-26870 [https://bugs.python.org/issue?@action=redirect&bpo=26870].)

rlcompleter

접두사가 밑줄로 시작하지 않는 한 비공개와 특수 어트리뷰트 이름은 이제 생략됩니다. 일부 완성된 키워드 뒤에 스페이스나 콜론이 추가됩니다. (Contributed by Serhiy Storchaka in bpo-25011 [https://bugs.python.org/issue?@action=redirect&bpo=25011] and bpo-25209 [https://bugs.python.org/issue?@action=redirect&bpo=25209].)

shlex

shlex는 구두점으로 처리되는 문자를 제어하기 위한 새로운 punctuation_chars 인자를 통해 훨씬 개선된 셸 호환성을 갖습니다. (Contributed by Vinay Sajip in bpo-1521950 [https://bugs.python.org/issue?@action=redirect&bpo=1521950].)

site

When specifying paths to add to sys.path in a .pth file, you may now specify file paths on top of directories (e.g. zip files). (Contributed by Wolfgang Langner in bpo-26587 [https://bugs.python.org/issue?@action=redirect&bpo=26587]).

sqlite3

sqlite3.Cursor.lastrowid는 이제 REPLACE 문을 지원합니다. (Contributed by Alex LordThorsen in bpo-16864 [https://bugs.python.org/issue?@action=redirect&bpo=16864].)

socket

The ioctl() function now supports the SIO_LOOPBACK_FAST_PATH control code. (Contributed by Daniel Stokes in bpo-26536 [https://bugs.python.org/issue?@action=redirect&bpo=26536].)

getsockopt() 상수 SO_DOMAIN, SO_PROTOCOL, SO_PEERSEC 및 SO_PASSSEC이 이제 지원됩니다. (Contributed by Christian Heimes in bpo-26907 [https://bugs.python.org/issue?@action=redirect&bpo=26907].)

setsockopt()는 이제 setsockopt(level, optname, None, optlen: int) 형식을 지원합니다. (Contributed by Christian Heimes in bpo-27744 [https://bugs.python.org/issue?@action=redirect&bpo=27744].)

The socket module now supports the address family AF_ALG to interface with Linux Kernel crypto API. ALG_*, SOL_ALG and sendmsg_afalg() were added. (Contributed by Christian Heimes in bpo-27744 [https://bugs.python.org/issue?@action=redirect&bpo=27744] with support from Victor Stinner.)

New Linux constants TCP_USER_TIMEOUT and TCP_CONGESTION were added. (Contributed by Omar Sandoval, bpo-26273 [https://bugs.python.org/issue?@action=redirect&bpo=26273]).

socketserver

http.server, xmlrpc.server 및 wsgiref.simple_server에 정의된 것들을 포함하여, socketserver 모듈에 기반하는 서버는 이제 컨텍스트 관리자 프로토콜을 지원합니다. (Contributed by Aviv Palivoda in bpo-26404 [https://bugs.python.org/issue?@action=redirect&bpo=26404].)

StreamRequestHandler 클래스의 wfile 어트리뷰트는 이제 io.BufferedIOBase 쓰기 가능한 인터페이스를 구현합니다. 특히 write()를 호출하면 이제 데이터 전체를 보냄이 보장됩니다. (Contributed by Martin Panter in bpo-26721 [https://bugs.python.org/issue?@action=redirect&bpo=26721].)

ssl

ssl은 OpenSSL 1.1.0을 지원합니다. 최소 권장 버전은 1.0.2입니다. (Contributed by Christian Heimes in bpo-26470 [https://bugs.python.org/issue?@action=redirect&bpo=26470].)

3DES는 기본 암호 스위트에서 제거되었으며 ChaCha20 Poly1305 암호 스위트가 추가되었습니다. (Contributed by Christian Heimes in bpo-27850 [https://bugs.python.org/issue?@action=redirect&bpo=27850] and bpo-27766 [https://bugs.python.org/issue?@action=redirect&bpo=27766].)

SSLContext는 옵션과 암호에 대해 더 나은 기본 구성을 제공합니다. (Contributed by Christian Heimes in bpo-28043 [https://bugs.python.org/issue?@action=redirect&bpo=28043].)

SSL 세션은 새로운 SSLSession 클래스를 사용하여, 한 클라이언트 측 연결에서 다른 연결로 복사 할 수 있습니다. TLS 세션 재개는 초기 핸드 셰이크 속도를 높이고, 지연 시간을 줄이며 성능을 향상할 수 있습니다 (Contributed by Christian Heimes in bpo-19500 [https://bugs.python.org/issue?@action=redirect&bpo=19500] based on a draft by Alex Warhawk.)

새로운 get_ciphers() 메서드를 사용하여 암호 우선순위에 따라 활성화된 암호 리스트를 가져올 수 있습니다.

모든 상수와 플래그가 IntEnum과 IntFlags로 변환되었습니다. (Contributed by Christian Heimes in bpo-28025 [https://bugs.python.org/issue?@action=redirect&bpo=28025].)

SSLContext를 위한 서버와 클라이언트 측 특정 TLS 프로토콜이 추가되었습니다. (Contributed by Christian Heimes in bpo-28085 [https://bugs.python.org/issue?@action=redirect&bpo=28085].)

Added ssl.SSLContext.post_handshake_auth to enable and ssl.SSLSocket.verify_client_post_handshake() to initiate TLS 1.3 post-handshake authentication. (Contributed by Christian Heimes in gh-78851 [https://github.com/python/cpython/issues/78851].)

statistics

새로운 harmonic_mean() 함수가 추가되었습니다. (Contributed by Steven D’Aprano in bpo-27181 [https://bugs.python.org/issue?@action=redirect&bpo=27181].)

struct

struct는 이제 'e' 포맷 지정자를 통해 IEEE 754 반 정밀도 부동 소수점을 지원합니다. (Contributed by Eli Stevens, Mark Dickinson in bpo-11734 [https://bugs.python.org/issue?@action=redirect&bpo=11734].)

subprocess

subprocess.Popen 파괴자는 이제 자식 프로세스가 계속 실행 중이면 ResourceWarning 경고를 내보냅니다. 자식 프로세스의 종료 상태를 읽으려면, 컨텍스트 관리자 프로토콜(with proc: ...)을 사용하거나 wait() 메서드를 명시적으로 호출하십시오. (Contributed by Victor Stinner in bpo-26741 [https://bugs.python.org/issue?@action=redirect&bpo=26741].)

subprocess.Popen 생성자와 그것을 통해 인자를 전달하는 모든 함수는 이제 encoding과 errors 인자를 받아들입니다. 이들 중 하나를 지정하면 stdin, stdout 및 stderr 스트림에 대한 텍스트 모드가 활성화됩니다. (Contributed by Steve Dower in bpo-6135 [https://bugs.python.org/issue?@action=redirect&bpo=6135].)

sys

새로운 getfilesystemencodeerrors() 함수는 유니코드 파일명과 바이트열 파일명 사이를 변환하는 데 사용되는 에러 모드의 이름을 반환합니다. (Contributed by Steve Dower in bpo-27781 [https://bugs.python.org/issue?@action=redirect&bpo=27781].)

윈도우에서 getwindowsversion() 함수의 반환 값에는 이제 프로세스에 대해 에뮬레이션 되는 버전이 아니라 현재 운영 체제의 정확한 주 버전, 부 버전 및 빌드 번호가 포함된 platform_version 필드가 포함됩니다 (Contributed by Steve Dower in bpo-27932 [https://bugs.python.org/issue?@action=redirect&bpo=27932].)

telnetlib

telnetlib.Telnet is now a context manager (contributed by Stéphane Wirtel in bpo-25485 [https://bugs.python.org/issue?@action=redirect&bpo=25485]).

time

struct_time 어트리뷰트 tm_gmtoff와 tm_zone은 이제 모든 플랫폼에서 사용할 수 있습니다.

timeit

총 실행 시간이 200밀리초 이상이 되도록 Timer.timeit()을 반복적으로 호출하는 새로운 Timer.autorange() 편의 메서드가 추가되었습니다. (Contributed by Steven D’Aprano in bpo-6422 [https://bugs.python.org/issue?@action=redirect&bpo=6422].)

timeit은 이제 최상과 최악 시간 사이에 상당한 (4x) 차이가 있을 때 경고합니다. (Contributed by Serhiy Storchaka in bpo-23552 [https://bugs.python.org/issue?@action=redirect&bpo=23552].)

tkinter

tkinter.Variable 클래스에 trace_add(), trace_remove() 및 trace_info() 메서드를 추가했습니다. 오래된 Tcl 명령을 사용하는 이전 메서드 trace_variable(), trace(), trace_vdelete() 및 trace_vinfo()를 대체하며 Tcl의 향후 버전에서는 작동하지 않을 수 있습니다. (Contributed by Serhiy Storchaka in bpo-22115 [https://bugs.python.org/issue?@action=redirect&bpo=22115]).

traceback

traceback 모듈과 인터프리터의 내장 예외 디스플레이는 이제 다음 예제와 같이 트레이스백에서 반복되는 긴 시퀀스의 줄을 축약합니다:

>>> def f(): f()
...
>>> f()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 1, in f
  File "<stdin>", line 1, in f
  File "<stdin>", line 1, in f
  [Previous line repeated 995 more times]
RecursionError: maximum recursion depth exceeded

(Contributed by Emanuel Barry in bpo-26823 [https://bugs.python.org/issue?@action=redirect&bpo=26823].)

tracemalloc

tracemalloc 모듈은 이제 여러 다른 주소 공간에서 메모리 할당 추적을 지원합니다.

새로운 DomainFilter 필터 클래스가 주소 공간(도메인)별로 블록 추적을 필터링하기 위해 추가되었습니다.

(Contributed by Victor Stinner in bpo-26588 [https://bugs.python.org/issue?@action=redirect&bpo=26588].)

typing

typing 모듈이 잠정적이므로, 파이썬 3.6에 도입된 모든 변경 사항은 파이썬 3.5.x로 역 이식되었습니다.

typing 모듈은 제네릭 형 에일리어스에 대한 훨씬 향상된 지원을 제공합니다. 예를 들어 Dict[str, Tuple[S, T]]는 이제 유효한 형 어노테이션입니다. (Contributed by Guido van Rossum in Github #195 [https://github.com/python/typing/pull/195].)

contextlib.AbstractContextManager를 나타내는 typing.ContextManager 클래스가 추가되었습니다. (Contributed by Brett Cannon in bpo-25609 [https://bugs.python.org/issue?@action=redirect&bpo=25609].)

collections.abc.Collection을 나타내는 typing.Collection 클래스가 추가되었습니다. (Contributed by Ivan Levkivskyi in bpo-27598 [https://bugs.python.org/issue?@action=redirect&bpo=27598].)

클래스 변수를 표시하기 위해 typing.ClassVar 형 구조가 추가되었습니다. PEP 526 [https://peps.python.org/pep-0526/]에 도입된 대로, ClassVar에 래핑 된 변수 어노테이션은 주어진 어트리뷰트가 클래스 변수로 사용되도록 의도되었으며 해당 클래스의 인스턴스에 설정되어서는 안 됨을 나타냅니다. (Contributed by Ivan Levkivskyi in Github #280 [https://github.com/python/typing/pull/280].)

정적 형 검사기가 True로 가정하지만, 실행 시간에는 False인 새 TYPE_CHECKING 상수. (Contributed by Guido van Rossum in Github #230 [https://github.com/python/typing/issues/230].)

어노테이션에 대한 경량 고유 형을 만드는 새로운 NewType() 도우미 함수가 추가되었습니다:

from typing import NewType

UserId = NewType('UserId', int)
some_id = UserId(524313)

정적 형 검사기는 새 형을 원래 형의 서브 클래스인 것처럼 처리합니다. (Contributed by Ivan Levkivskyi in Github #189 [https://github.com/python/typing/issues/189].)

unicodedata

The unicodedata module now uses data from Unicode 9.0.0 [https://unicode.org/versions/Unicode9.0.0/]. (Contributed by Benjamin Peterson.)

unittest.mock

Mock 클래스는 다음과 같이 개선되었습니다:

모의 객체가 호출되었는지 확인하는 두 가지 새로운 메서드, Mock.assert_called()와 Mock.assert_called_once(). (Contributed by Amit Saha in bpo-26323 [https://bugs.python.org/issue?@action=redirect&bpo=26323].)

Mock.reset_mock() 메서드에는 이제 두 개의 선택적 키워드 전용 인자가 있습니다: return_value와 side_effect. (Contributed by Kushal Das in bpo-21271 [https://bugs.python.org/issue?@action=redirect&bpo=21271].)

urllib.request

HTTP 요청에 파일이나 이터러블 본문(바이트열 객체가 아닌)이 있지만, Content-Length 헤더가 없으면, 에러를 던지는 대신, AbstractHTTPHandler는 이제 청크 전송 인코딩(chunked transfer encoding)을 사용하도록 폴백 됩니다. (Contributed by Demian Brecht and Rolf Krahl in bpo-12319 [https://bugs.python.org/issue?@action=redirect&bpo=12319].)

urllib.robotparser

RobotFileParser는 이제 Crawl-delay와 Request-rate 확장을 지원합니다. (Contributed by Nikolay Bogoychev in bpo-16099 [https://bugs.python.org/issue?@action=redirect&bpo=16099].)

venv

venv는 새 파라미터 --prompt를 받아들입니다. 이 파라미터는 가상 환경에 대한 대체 접두사를 제공합니다. (Proposed by Łukasz Balcerzak and ported to 3.6 by Stéphane Wirtel in bpo-22829 [https://bugs.python.org/issue?@action=redirect&bpo=22829].)

warnings

새로운 선택적 source 매개 변수가 warnings.warn_explicit() 함수에 추가되었습니다: ResourceWarning을 방출한 파괴된 객체. source 어트리뷰트는 warnings.WarningMessage에도 추가되었습니다 (contributed by Victor Stinner in bpo-26568 [https://bugs.python.org/issue?@action=redirect&bpo=26568] and bpo-26567 [https://bugs.python.org/issue?@action=redirect&bpo=26567]).

ResourceWarning 경고가 로그 될 때, tracemalloc 모듈이 이제 파괴된 객체가 할당된 트레이스백을 얻는 데 사용됩니다.

example.py 스크립트의 예:

import warnings

def func():
    return open(__file__)

f = func()
f = None

python3.6 -Wd -X tracemalloc=5 example.py 명령의 출력:

example.py:7: ResourceWarning: unclosed file <_io.TextIOWrapper name='example.py' mode='r' encoding='UTF-8'>
  f = None
Object allocated at (most recent call first):
  File "example.py", lineno 4
    return open(__file__)
  File "example.py", lineno 6
    f = func()

“Object allocated at” 트레이스백은 새로운 것이며 tracemalloc이 파이썬 메모리 할당을 추적하고 warnings 모듈을 이미 임포트 했을 때만 표시됩니다.

winreg

64비트 정수 형 REG_QWORD를 추가했습니다. (Contributed by Clement Rouault in bpo-23026 [https://bugs.python.org/issue?@action=redirect&bpo=23026].)

winsound

키워드 인자가 Beep, MessageBeep 및 PlaySound 에 전달되도록 허용합니다 (bpo-27982 [https://bugs.python.org/issue?@action=redirect&bpo=27982]).

xmlrpc.client

xmlrpc.client 모듈은 이제 숫자와 None에 대해 Apache XML-RPC 구현에서 사용하는 추가 데이터형의 역 마셜링을 지원합니다. (Contributed by Serhiy Storchaka in bpo-26885 [https://bugs.python.org/issue?@action=redirect&bpo=26885].)

zipfile

새로운 ZipInfo.from_file() 클래스 메서드를 사용하면 파일 시스템 파일에서 ZipInfo 인스턴스를 만들 수 있습니다. 새로운 ZipInfo.is_dir() 메서드를 사용하여 ZipInfo 인스턴스가 디렉터리를 나타내는지 확인할 수 있습니다. (Contributed by Thomas Kluyver in bpo-26039 [https://bugs.python.org/issue?@action=redirect&bpo=26039].)

이제 ZipFile.open() 메서드를 사용하여 데이터를 추출할 뿐만 아니라, ZIP 파일에 데이터를 쓸 수 있습니다. (Contributed by Thomas Kluyver in bpo-26039 [https://bugs.python.org/issue?@action=redirect&bpo=26039].)

zlib

compress()와 decompress() 함수는 이제 키워드 인자를 받아들입니다. (Contributed by Aviv Palivoda in bpo-26243 [https://bugs.python.org/issue?@action=redirect&bpo=26243] and Xiang Zhang in bpo-16764 [https://bugs.python.org/issue?@action=redirect&bpo=16764] respectively.)

최적화

파이썬 인터프리터는 이제 바이트 코드 대신 16비트 워드 코드를 사용하여 여러 옵코드 최적화를 가능하게 했습니다. (Contributed by Demur Rumed with input and reviews from Serhiy Storchaka and Victor Stinner in bpo-26647 [https://bugs.python.org/issue?@action=redirect&bpo=26647] and bpo-28050 [https://bugs.python.org/issue?@action=redirect&bpo=28050].)

asyncio.Future 클래스에는 이제 최적화된 C 구현이 있습니다. (Contributed by Yury Selivanov and INADA Naoki in bpo-26081 [https://bugs.python.org/issue?@action=redirect&bpo=26081].)

asyncio.Task 클래스에는 이제 최적화된 C 구현이 있습니다. (Contributed by Yury Selivanov in bpo-28544 [https://bugs.python.org/issue?@action=redirect&bpo=28544].)

typing 모듈의 다양한 구현 개선 사항(가령 제네릭 형의 캐싱)을 통해 최대 30배의 성능 향상과 메모리 요구량 감소가 가능해졌습니다.

ASCII 디코더는 이제 에러 처리기 surrogateescape, ignore 및 replace에 대해 최대 60배 빠릅니다 (Contributed by Victor Stinner in bpo-24870 [https://bugs.python.org/issue?@action=redirect&bpo=24870]).

ASCII와 Latin1 인코더는 이제 에러 처리기 surrogateescape에 대해 최대 3배 빠릅니다 (Contributed by Victor Stinner in bpo-25227 [https://bugs.python.org/issue?@action=redirect&bpo=25227]).

UTF-8 인코더는 이제 에러 처리기 ignore, replace, surrogateescape, surrogatepass에 대해 최대 75배 빠릅니다 (Contributed by Victor Stinner in bpo-25267 [https://bugs.python.org/issue?@action=redirect&bpo=25267]).

UTF-8 디코더는 이제 에러 처리기 ignore, replace 및 surrogateescape에 대해 최대 15배 빠릅니다 (Contributed by Victor Stinner in bpo-25301 [https://bugs.python.org/issue?@action=redirect&bpo=25301]).

bytes % args는 이제 최대 2배 더 빠릅니다. (Contributed by Victor Stinner in bpo-25349 [https://bugs.python.org/issue?@action=redirect&bpo=25349]).

bytearray % args는 이제 2.5–5배 더 빠릅니다. (Contributed by Victor Stinner in bpo-25399 [https://bugs.python.org/issue?@action=redirect&bpo=25399]).

bytes.fromhex()와 bytearray.fromhex()를 최적화했습니다: 이제 2배에서 3.5배까지 빨라졌습니다. (Contributed by Victor Stinner in bpo-25401 [https://bugs.python.org/issue?@action=redirect&bpo=25401]).

bytes.replace(b'', b'.')와 bytearray.replace(b'', b'.')를 최적화했습니다: 최대 80% 더 빠릅니다. (Contributed by Josh Snider in bpo-26574 [https://bugs.python.org/issue?@action=redirect&bpo=26574]).

Allocator functions of the PyMem_Malloc() domain (PYMEM_DOMAIN_MEM) now use the pymalloc memory allocator instead of malloc() function of the C library. The pymalloc allocator is optimized for objects smaller or equal to 512 bytes with a short lifetime, and use malloc() for larger memory blocks. (Contributed by Victor Stinner in bpo-26249 [https://bugs.python.org/issue?@action=redirect&bpo=26249]).

pickle.load()와 pickle.loads()는 이제 많은 작은 객체를 역 직렬화할 때 최대 10% 더 빠릅니다 (Contributed by Victor Stinner in bpo-27056 [https://bugs.python.org/issue?@action=redirect&bpo=27056]).

키워드 인자를 함수에 전달하면 위치 인자를 전달하는 것과 비교하여 오버헤드가 있습니다. 이제 인자 클리닉(Argument Clinic)을 사용하여 구현된 확장 함수에서 이 오버헤드가 많이 감소합니다. (Contributed by Serhiy Storchaka in bpo-27574 [https://bugs.python.org/issue?@action=redirect&bpo=27574]).

glob 모듈에서 glob()과 iglob() 함수를 최적화했습니다; 이제 약 3–6배 더 빠릅니다. (Contributed by Serhiy Storchaka in bpo-25596 [https://bugs.python.org/issue?@action=redirect&bpo=25596]).

os.scandir()을 사용하여 pathlib에서 글로빙(globbing)을 최적화했습니다; 이제 약 1.5–4배 더 빨라졌습니다. (Contributed by Serhiy Storchaka in bpo-26032 [https://bugs.python.org/issue?@action=redirect&bpo=26032]).

xml.etree.ElementTree 구문 분석, 이터레이션 및 깊은 복사 성능이 크게 향상되었습니다. (Contributed by Serhiy Storchaka in bpo-25638 [https://bugs.python.org/issue?@action=redirect&bpo=25638], bpo-25873 [https://bugs.python.org/issue?@action=redirect&bpo=25873], and bpo-25869 [https://bugs.python.org/issue?@action=redirect&bpo=25869].)

이제 부동 소수점과 십진수(decimals)에서 fractions.Fraction 인스턴스를 생성하는 것이 2–3배 빨라졌습니다. (Contributed by Serhiy Storchaka in bpo-25971 [https://bugs.python.org/issue?@action=redirect&bpo=25971].)

빌드와 C API 변경

이제 파이썬을 빌드하려면 도구 체인에서 일부 C99 지원이 필요합니다. 특히, 파이썬은 이제 PY_LONG_LONG과 같은 사용자 정의 매크로 자리에 표준 정수 형과 매크로를 사용합니다. 자세한 내용은, PEP 7 [https://peps.python.org/pep-0007/]과 bpo-17884 [https://bugs.python.org/issue?@action=redirect&bpo=17884]를 참조하십시오.

안드로이드 NDK와 안드로이드 API 수준이 21 (안드로이드 5.0 Lollipop) 이상으로 CPython을 교차 컴파일하면 성공적으로 실행됩니다. 안드로이드는 아직 지원되는 플랫폼이 아니지만, 파이썬 테스트 스위트는 약 16번의 테스트 실패만으로 안드로이드 에뮬레이터에서 실행됩니다. 안드로이드 메타 이슈 bpo-26865 [https://bugs.python.org/issue?@action=redirect&bpo=26865]를 참조하세요.

--enable-optimizations 구성 플래그가 추가되었습니다. 이를 켜면 PGO와 같은 값 비싼 최적화가 활성화됩니다. (Original patch by Alecsandru Patrascu of Intel in bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359].)

The GIL must now be held when allocator functions of PYMEM_DOMAIN_OBJ (ex: PyObject_Malloc()) and PYMEM_DOMAIN_MEM (ex: PyMem_Malloc()) domains are called.

버퍼링 된 데이터 플러시가 실패했는지를 나타내는 새로운 Py_FinalizeEx() API. (Contributed by Martin Panter in bpo-5319 [https://bugs.python.org/issue?@action=redirect&bpo=5319].)

PyArg_ParseTupleAndKeywords() 는 이제 위치 전용 매개 변수를 지원합니다. 위치 전용 매개 변수는 빈 이름으로 정의됩니다. (Contributed by Serhiy Storchaka in bpo-26282 [https://bugs.python.org/issue?@action=redirect&bpo=26282]).

PyTraceback_Print 메서드는 이제 반복되는 줄의 긴 시퀀스를 "[Previous line repeated {count} more times]"로 줄여줍니다. (Contributed by Emanuel Barry in bpo-26823 [https://bugs.python.org/issue?@action=redirect&bpo=26823].)

새로운 PyErr_SetImportErrorSubclass() 함수를 사용하면 발생시킬 ImportError의 서브 클래스를 지정할 수 있습니다. (Contributed by Eric Snow in bpo-15767 [https://bugs.python.org/issue?@action=redirect&bpo=15767].)

새로운 PyErr_ResourceWarning() 함수는 리소스 할당의 소스를 제공하는 ResourceWarning을 생성하는 데 사용할 수 있습니다. (Contributed by Victor Stinner in bpo-26567 [https://bugs.python.org/issue?@action=redirect&bpo=26567].)

새로운 PyOS_FSPath() 함수는 경로류 객체의 파일 시스템 표현을 반환합니다. (Contributed by Brett Cannon in bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186].)

PyUnicode_FSConverter()와 PyUnicode_FSDecoder() 함수는 이제 경로류 객체를 받아들입니다.

기타 개선 사항

--version(약식 형식: -V)이 두 번 제공되면, 파이썬은 자세한 정보로 sys.version을 인쇄합니다.

$ ./python -VV
Python 3.6.0b4+ (3.6:223967b49e49+, Nov 21 2016, 20:55:04)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]

폐지

새 키워드

async와 await는 변수, 클래스, 함수 또는 모듈 이름으로 사용하지 않는 것이 좋습니다. 파이썬 3.5에서 PEP 492 [https://peps.python.org/pep-0492/]에 의해 도입되었으며, 파이썬 3.7에서 정식 키워드가 될 것입니다. 파이썬 3.6부터, async나 await를 이름으로 사용하면 DeprecationWarning이 생성됩니다.

폐지된 파이썬 동작

제너레이터 내에서 StopIteration 예외를 발생시키면 이제 DeprecationWarning이 생성되고, 파이썬 3.7에서는 RuntimeError가 트리거될 것입니다. 자세한 내용은 PEP 479: 제너레이터 내부에서의 StopIteration 처리 변경를 참조하십시오.

이제 __aiter__() 메서드는 이전과 같이 어웨이터블을 반환하는 대신 비동기 이터레이터를 직접 반환해야 합니다. 전자를 수행하면 DeprecationWarning이 트리거됩니다. 이전 버전과의 호환성은 파이썬 3.7에서 제거될 것입니다. (Contributed by Yury Selivanov in bpo-27243 [https://bugs.python.org/issue?@action=redirect&bpo=27243].)

유효한 이스케이프 시퀀스가 아닌 역 슬래시 문자 쌍은 이제 DeprecationWarning을 생성합니다. 이것은 결국 SyntaxError가 될 것이지만, 몇 번의 파이썬 릴리스에서는 그렇게 되지 않을 것입니다. (Contributed by Emanuel Barry in bpo-27364 [https://bugs.python.org/issue?@action=redirect&bpo=27364].)

상대 임포트를 수행할 때, __spec__이나 __package__가 정의되지 않을 때 호출하는 모듈에서 __name__과 __path__로 폴백하면 이제 ImportWarning이 발생합니다. (Contributed by Rose Ames in bpo-25791 [https://bugs.python.org/issue?@action=redirect&bpo=25791].)

폐지된 파이썬 모듈, 함수 및 메서드

asynchat

The asynchat has been deprecated in favor of asyncio. (Contributed by Mariatta in bpo-25002 [https://bugs.python.org/issue?@action=redirect&bpo=25002].)

asyncore

The asyncore has been deprecated in favor of asyncio. (Contributed by Mariatta in bpo-25002 [https://bugs.python.org/issue?@action=redirect&bpo=25002].)

dbm

다른 dbm 구현과 달리, dbm.dumb 모듈은 'rw' 모드로 데이터베이스를 만들고 'r' 모드로 열린 데이터베이스를 수정할 수 있습니다. 이 동작은 이제 폐지되었고 3.8에서 제거됩니다. (Contributed by Serhiy Storchaka in bpo-21708 [https://bugs.python.org/issue?@action=redirect&bpo=21708].)

distutils

The undocumented extra_path argument to the distutils.Distribution constructor is now considered deprecated and will raise a warning if set. Support for this parameter will be removed in a future Python release. See bpo-27919 [https://bugs.python.org/issue?@action=redirect&bpo=27919] for details.

grp

getgrgid()에서 정수가 아닌 인자에 대한 지원은 폐지되었습니다. (Contributed by Serhiy Storchaka in bpo-26129 [https://bugs.python.org/issue?@action=redirect&bpo=26129].)

importlib

importlib.machinery.SourceFileLoader.load_module()과 importlib.machinery.SourcelessFileLoader.load_module() 메서드는 이제 폐지되었습니다. 이들은 importlib.abc.Loader.exec_module()로 대체하도록 이전 버전의 파이썬에서 폐지되지 않은 importlib에 있는 유일한 importlib.abc.Loader.load_module() 구현입니다.

The importlib.machinery.WindowsRegistryFinder class is now deprecated. As of 3.6.0, it is still added to sys.meta_path by default (on Windows), but this may change in future releases.

os

os 함수, compile() 및 유사한 함수에서 경로로 일반 바이트열류 객체에 대한 문서화되지 않은 지원은 이제 폐지되었습니다. (Contributed by Serhiy Storchaka in bpo-25791 [https://bugs.python.org/issue?@action=redirect&bpo=25791] and bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754].)

re

정규식 중간에 있는 인라인 플래그 (?letters)에 대한 지원은 폐지되었고 향후 파이썬 버전에서 제거됩니다. 정규식 시작 부분의 플래그는 계속 허용됩니다. (Contributed by Serhiy Storchaka in bpo-22493 [https://bugs.python.org/issue?@action=redirect&bpo=22493].)

ssl

OpenSSL 0.9.8, 1.0.0 및 1.0.1은 폐지되었고 더는 지원되지 않습니다. 향후에 ssl 모듈에는 최소한 OpenSSL 1.0.2나 1.1.0이 필요합니다.

ftplib, http.client, imaplib, poplib 및 smtplib에서 certfile, keyfile 및 check_hostname과 같은 SSL 관련 인자는 폐지되었고 context로 대체합니다. (Contributed by Christian Heimes in bpo-28022 [https://bugs.python.org/issue?@action=redirect&bpo=28022].)

ssl 모듈의 몇 가지 프로토콜과 함수는 이제 폐지되었습니다. 일부 기능은 향후 버전의 OpenSSL에서 더는 사용할 수 없을 것입니다. 다른 기능들이 폐지되었고 다른 API로 대체합니다. (Contributed by Christian Heimes in bpo-28022 [https://bugs.python.org/issue?@action=redirect&bpo=28022] and bpo-26470 [https://bugs.python.org/issue?@action=redirect&bpo=26470].)

tkinter

The tkinter.tix module is now deprecated. tkinter users should use tkinter.ttk instead.

venv

pyvenv 스크립트는 폐지되었고 python3 -m venv로 대체합니다. 이것은 pyvenv가 연결되어있는 파이썬 인터프리터가 무엇이고 따라서 가상 환경에서 어떤 파이썬 인터프리터가 사용될 것인지에 대한 혼동을 방지합니다. (Contributed by Brett Cannon in bpo-25154 [https://bugs.python.org/issue?@action=redirect&bpo=25154].)

xml

As mitigation against DTD and external entity retrieval, the xml.dom.minidom and xml.sax modules no longer process external entities by default. (Contributed by Christian Heimes in gh-61441 [https://github.com/python/cpython/issues/61441].)

C API의 폐지된 함수와 형

Undocumented functions PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(), PyUnicode_AsEncodedUnicode() and PyUnicode_AsDecodedUnicode() are deprecated now. Use the generic codec based API instead.

폐지된 빌드 옵션

--with-system-ffi 구성 플래그는 이제 비 macOS 유닉스 플랫폼에서 기본적으로 켜집니다. --without-system-ffi를 사용하여 비활성화 할 수 있지만, 플래그 사용은 폐지되었고 파이썬 3.7에서는 허용되지 않을 것입니다. macOS는 이 변경의 영향을 받지 않습니다. 많은 OS 배포자는 시스템 파이썬을 빌드할 때 이미 --with-system-ffi 플래그를 사용함에 유의하십시오.

제거

API와 기능 제거

정규식에서 '\'와 ASCII 문자로 구성된 알 수 없는 이스케이프는 이제 에러를 발생시킵니다. re.sub()의 치환 템플릿에서는 여전히 허용되지만, 폐지되었습니다. re.LOCALE 플래그는 이제 바이너리 패턴에서만 사용할 수 있습니다.

inspect.getmoduleinfo()가 제거되었습니다 (CPython 3.3부터 폐지되었습니다). inspect.getmodulename()은 주어진 경로에 대한 모듈 이름을 얻는 데 사용해야 합니다. (Contributed by Yury Selivanov in bpo-13248 [https://bugs.python.org/issue?@action=redirect&bpo=13248].)

traceback.Ignore 클래스와 traceback.usage, traceback.modname, traceback.fullmodname, traceback.find_lines_from_code, traceback.find_lines, traceback.find_strings, traceback.find_executable_lines 메서드가 traceback 모듈에서 제거되었습니다. 그것들은 파이썬 3.2 이후 폐지된 문서화되지 않은 메서드였으며 동등한 기능은 비공개 메서드에서 사용할 수 있습니다.

tkinter 위젯 클래스의 tk_menuBar()와 tk_bindForTraversal() 더미 메서드가 제거되었습니다 (해당 Tk 명령은 Tk 4.0 이후로 사용되지 않습니다).

zipfile.ZipFile 클래스의 open() 메서드는 더는 'U' 모드를 지원하지 않습니다 (파이썬 3.4부터 폐지되었습니다). 유니버설 줄 넘김 모드에서 압축된 텍스트 파일을 읽으려면 io.TextIOWrapper를 사용하십시오.

The undocumented IN, CDROM, DLFCN, TYPES, CDIO, and STROPTS modules have been removed. They had been available in the platform specific Lib/plat-*/ directories, but were chronically out of date, inconsistently available across platforms, and unmaintained. The script that created these modules is still available in the source distribution at Tools/scripts/h2py.py [https://github.com/python/cpython/blob/v3.6.15/Tools/scripts/h2py.py].

폐지된 asynchat.fifo 클래스가 제거되었습니다.

파이썬 3.6으로 이식하기

이 섹션에서는 여러분의 코드 변경이 필요할 수 있는 이전에 설명한 변경 사항과 기타 버그 수정을 나열합니다.

‘python’ 명령 동작의 변경 사항

정의된 COUNT_ALLOCS, SHOW_ALLOC_COUNT 또는 SHOW_TRACK_COUNT 매크로가 있는 특수 파이썬 빌드의 출력은 이제 기본적으로 꺼져 있습니다. -X showalloccount 옵션을 사용하여 다시 활성화할 수 있습니다. 이제 stdout 대신 stderr로 출력됩니다. (Contributed by Serhiy Storchaka in bpo-23034 [https://bugs.python.org/issue?@action=redirect&bpo=23034].)

파이썬 API의 변경 사항

open()은 더는 'U' 모드 플래그를 '+'와 결합하는 것을 허용하지 않습니다. (Contributed by Jeff Balogh and John O’Connor in bpo-2091 [https://bugs.python.org/issue?@action=redirect&bpo=2091].)

sqlite3은 더는 DDL 문 이전에 열린 트랜잭션을 묵시적으로 커밋하지 않습니다.

리눅스에서, os.urandom()은 이제 보안을 강화하기 위해 시스템 urandom 엔트로피 풀이 초기화될 때까지 블록합니다.

importlib.abc.Loader.exec_module()이 정의되면, importlib.abc.Loader.create_module()도 정의되어야 합니다.

PyErr_SetImportError()는 이제 msg 인자가 설정되지 않았을 때 TypeError를 설정합니다. 이전에는 NULL만 반환되었습니다.

The format of the co_lnotab attribute of code objects changed to support a negative line number delta. By default, Python does not emit bytecode with a negative line number delta. Functions using frame.f_lineno, PyFrame_GetLineNumber() or PyCode_Addr2Line() are not affected. Functions directly decoding co_lnotab should be updated to use a signed 8-bit integer type for the line number delta, but this is only required to support applications using a negative line number delta. See Objects/lnotab_notes.txt for the co_lnotab format and how to decode it, and see the PEP 511 [https://peps.python.org/pep-0511/] for the rationale.

compileall 모듈의 함수는 이제 1이나 0 대신 불리언을 반환하여 각각 성공이나 실패를 나타냅니다. 불리언은 정수의 서브 클래스이기 때문에, 1이나 0에 대한 아이덴티티 검사를 수행하는 경우에만 문제가 됩니다. bpo-25768 [https://bugs.python.org/issue?@action=redirect&bpo=25768]을 참조하십시오.

urllib.parse.urlsplit()과 urlparse() 결과의 port 어트리뷰트를 읽으면 범위를 벗어난 값에 대해 이제 None을 반환하는 대신 ValueError가 발생합니다. bpo-20059 [https://bugs.python.org/issue?@action=redirect&bpo=20059]를 참조하십시오.

The imp module now raises a DeprecationWarning instead of PendingDeprecationWarning.

The following modules have had missing APIs added to their __all__ attributes to match the documented APIs: calendar, cgi, csv, ElementTree, enum, fileinput, ftplib, logging, mailbox, mimetypes, optparse, plistlib, smtpd, subprocess, tarfile, threading and wave. This means they will export new symbols when import * is used. (Contributed by Joel Taddei and Jacek Kołodziej in bpo-23883 [https://bugs.python.org/issue?@action=redirect&bpo=23883].)

상대 임포트를 수행할 때, __package__가 __spec__.parent와 같다고 비교되지 않으면 ImportWarning이 발생합니다. (Contributed by Brett Cannon in bpo-25791 [https://bugs.python.org/issue?@action=redirect&bpo=25791].)

상대 임포트가 수행되고 부모 패키지가 알려지지 않았으면, ImportError가 발생합니다. 이전에는, SystemError를 발생시킬 수 있었습니다. (Contributed by Brett Cannon in bpo-18018 [https://bugs.python.org/issue?@action=redirect&bpo=18018].)

http.server, xmlrpc.server 및 wsgiref.simple_server에 정의된 서버를 포함하여, socketserver 모듈을 기반으로 하는 서버는 이제 Exception에서 파생된 예외만 포착합니다. 따라서 요청 처리기가 SystemExit나 KeyboardInterrupt와 같은 예외를 발생시키면, handle_error()가 더는 호출되지 않고, 예외로 인해 단일 스레드 서버가 중지됩니다. (Contributed by Martin Panter in bpo-23430 [https://bugs.python.org/issue?@action=redirect&bpo=23430].)

spwd.getspnam() now raises a PermissionError instead of KeyError if the user doesn’t have privileges.

socket.socket.close() 메서드는 하부 시스템 호출에 의해 에러(예를 들어 EBADF)가 보고되면 예외를 발생시킵니다. (Contributed by Martin Panter in bpo-26685 [https://bugs.python.org/issue?@action=redirect&bpo=26685].)

The decode_data argument for the smtpd.SMTPChannel and smtpd.SMTPServer constructors is now False by default. This means that the argument passed to process_message() is now a bytes object by default, and process_message() will be passed keyword arguments. Code that has already been updated in accordance with the deprecation warning generated by 3.5 will not be affected.

json 모듈의 dump(), dumps(), load() 및 loads() 함수와 JSONEncoder와 JSONDecoder 클래스 생성자의 모든 선택적 인자는 이제 키워드 전용입니다. (Contributed by Serhiy Storchaka in bpo-18726 [https://bugs.python.org/issue?@action=redirect&bpo=18726].)

type.__new__를 재정의하지 않는 type의 서브 클래스는 더는 단일 인자 형식을 사용하여 객체 형을 가져올 수 없습니다.

PEP 487 [https://peps.python.org/pep-0487/]의 일부로, type에 전달된 키워드 인자 (메타 클래스 힌트 metaclass 제외) 처리가 이제 일관되게 object.__init_subclass__()에 위임됩니다. 즉, type.__new__()와 type.__init__()는 이제 임의의 키워드 인자를 받아들이지만, object.__init_subclass__()(type.__new__()에서 호출됨)는 기본적으로 이를 거부합니다. 추가 키워드 인자를 받아들이는 사용자 정의 메타 클래스는 그에 따라 type.__new__()에 대한 호출을 조정해야 합니다 (직접 또는 super를 통해).

In distutils.command.sdist.sdist, the default_format attribute has been removed and is no longer honored. Instead, the gzipped tarfile format is the default on all platforms and no platform-specific selection is made. In environments where distributions are built on Windows and zip distributions are required, configure the project with a setup.cfg file containing the following:

[sdist]
formats=zip

이 동작은 Setuptools 26.0.0에 의해 이전 파이썬 버전으로 역 이식되었습니다.

urllib.request 모듈과 http.client.HTTPConnection.request() 메서드에서, Content-Length 헤더 필드가 지정되지 않았고 요청 본문이 파일 객체이면, 이제 HTTP 1.1 청크 인코딩(chunked encoding)으로 전송됩니다. 파일 객체를 HTTP 1.0 서버로 보내야 하면, 이제 호출자가 Content-Length 값을 지정해야 합니다. (Contributed by Demian Brecht and Rolf Krahl with tweaks from Martin Panter in bpo-12319 [https://bugs.python.org/issue?@action=redirect&bpo=12319].)

DictReader는 이제 OrderedDict 형의 행을 반환합니다. (Contributed by Steve Holden in bpo-27842 [https://bugs.python.org/issue?@action=redirect&bpo=27842].)

The crypt.METHOD_CRYPT will no longer be added to crypt.methods if unsupported by the platform. (Contributed by Victor Stinner in bpo-25287 [https://bugs.python.org/issue?@action=redirect&bpo=25287].)

namedtuple()에 대한 verbose와 rename 인자는 이제 키워드 전용입니다. (Contributed by Raymond Hettinger in bpo-25628 [https://bugs.python.org/issue?@action=redirect&bpo=25628].)

리눅스에서, ctypes.util.find_library()는 이제 LD_LIBRARY_PATH에서 공유 라이브러리를 찾습니다. (Contributed by Vinay Sajip in bpo-9998 [https://bugs.python.org/issue?@action=redirect&bpo=9998].)

imaplib.IMAP4 클래스는 이제 서버에서 보낸 메시지의 ']' 문자를 포함하는 플래그를 처리하여 실세계 호환성을 향상합니다. (Contributed by Lita Cho in bpo-21815 [https://bugs.python.org/issue?@action=redirect&bpo=21815].)

mmap.write() 함수는 이제 다른 쓰기 메서드와 같이 기록된 바이트 수를 반환합니다. (Contributed by Jakub Stasiak in bpo-26335 [https://bugs.python.org/issue?@action=redirect&bpo=26335].)

pkgutil.iter_modules()와 pkgutil.walk_packages() 함수는 네임드 튜플 ModuleInfo를 반환합니다. (Contributed by Ramchandra Apte in bpo-17211 [https://bugs.python.org/issue?@action=redirect&bpo=17211].)

re.sub()는 이제 문자열에서 패턴을 찾을 수 없는 경우에도 치환 템플릿에 있는 잘못된 숫자 그룹 참조에 대해 에러를 발생시킵니다. 이제 잘못된 그룹 참조에 대한 에러 메시지에 그룹 인덱스와 참조 위치가 포함됩니다. (Contributed by SilentGhost, Serhiy Storchaka in bpo-25953 [https://bugs.python.org/issue?@action=redirect&bpo=25953].)

zipfile.ZipFile은 이제 인식할 수 없는 압축 값에 대해 NotImplementedError 를 발생시킵니다. 이전에는 일반 RuntimeError가 발생했습니다. 또한, 닫힌 ZipFile에서 ZipFile 메서드를 호출하거나 'r' 모드로 만든 ZipFile에서 write() 메서드를 호출하면 ValueError가 발생합니다. 이전에는, 이러한 시나리오에서 RuntimeError가 발생했습니다.

사용자 정의 메타 클래스가 인자가 없는 super()나 메서드에서 묵시적 __class__ 클로저 변수로의 직접 참조와 결합할 때, 묵시적 __classcell__ 이름 공간 항목은 이제 초기화를 위해 type.__new__까지 전달되어야 합니다. 그렇게 하지 않으면 파이썬 3.6에서는 DeprecationWarning이, 파이썬 3.8에서는 RuntimeError가 발생합니다.

With the introduction of ModuleNotFoundError, import system consumers may start expecting import system replacements to raise that more specific exception when appropriate, rather than the less-specific ImportError. To provide future compatibility with such consumers, implementers of alternative import systems that completely replace __import__() will need to update their implementations to raise the new subclass when a module can’t be found at all. Implementers of compliant plugins to the default import system shouldn’t need to make any changes, as the default import system will raise the new subclass when appropriate.

C API의 변경 사항

PyMem_Malloc() 할당자 패밀리는 이제 시스템 malloc()이 아닌 pymalloc 할당자를 사용합니다. 이제 GIL을 보유하지 않고 PyMem_Malloc()을 호출하는 응용 프로그램이 충돌할 수 있습니다. 응용 프로그램에서 메모리 할당자의 사용을 확인하려면 PYTHONMALLOC 환경 변수를 debug로 설정하십시오. bpo-26249 [https://bugs.python.org/issue?@action=redirect&bpo=26249]를 참조하십시오.

Py_Exit()(그리고 메인 인터프리터)는 이제 버퍼링 된 데이터를 플러시 하지 못하면 종료 상태를 120으로 재정의합니다. bpo-5319 [https://bugs.python.org/issue?@action=redirect&bpo=5319]를 참조하십시오.

CPython 바이트 코드 변경 사항

파이썬 3.6에서 바이트 코드에 몇 가지 주요 변경 사항이 있습니다.

파이썬 인터프리터는 이제 바이트 코드 대신 16비트 워드 코드를 사용합니다. (Contributed by Demur Rumed with input and reviews from Serhiy Storchaka and Victor Stinner in bpo-26647 [https://bugs.python.org/issue?@action=redirect&bpo=26647] and bpo-28050 [https://bugs.python.org/issue?@action=redirect&bpo=28050].)

The new FORMAT_VALUE and BUILD_STRING opcodes as part of the formatted string literal implementation. (Contributed by Eric Smith in bpo-25483 [https://bugs.python.org/issue?@action=redirect&bpo=25483] and Serhiy Storchaka in bpo-27078 [https://bugs.python.org/issue?@action=redirect&bpo=27078].)

The new BUILD_CONST_KEY_MAP opcode to optimize the creation of dictionaries with constant keys. (Contributed by Serhiy Storchaka in bpo-27140 [https://bugs.python.org/issue?@action=redirect&bpo=27140].)

The function call opcodes have been heavily reworked for better performance and simpler implementation. The MAKE_FUNCTION, CALL_FUNCTION, CALL_FUNCTION_KW and BUILD_MAP_UNPACK_WITH_CALL opcodes have been modified, the new CALL_FUNCTION_EX and BUILD_TUPLE_UNPACK_WITH_CALL have been added, and CALL_FUNCTION_VAR, CALL_FUNCTION_VAR_KW and MAKE_CLOSURE opcodes have been removed. (Contributed by Demur Rumed in bpo-27095 [https://bugs.python.org/issue?@action=redirect&bpo=27095], and Serhiy Storchaka in bpo-27213 [https://bugs.python.org/issue?@action=redirect&bpo=27213], bpo-28257 [https://bugs.python.org/issue?@action=redirect&bpo=28257].)

The new SETUP_ANNOTATIONS and STORE_ANNOTATION opcodes have been added to support the new variable annotation syntax. (Contributed by Ivan Levkivskyi in bpo-27985 [https://bugs.python.org/issue?@action=redirect&bpo=27985].)

파이썬 3.6.2의 주목할만한 변경 사항

새로운 make regen-all 빌드 대상

교차 컴파일을 단순화하고, 기존 버전의 파이썬을 이미 사용할 수 있을 필요 없이 CPython을 안정적으로 컴파일 할 수 있도록, autotools 기반 빌드 시스템은 더는 파일 수정 시간을 기반으로 생성된 파일을 묵시적으로 재컴파일하려고 시도하지 않습니다.

대신, 원할 때 이러한 파일을 강제로 재생성하기 위해 새로운 make regen-all 명령이 추가되었습니다 (예를 들어 사전 생성된 버전을 기반으로 파이썬의 초기 버전이 이미 빌드된 후).

더 선택적인 재생성 대상도 정의됩니다 - 자세한 내용은 Makefile.pre.in [https://github.com/python/cpython/tree/main/Makefile.pre.in]을 참조하십시오.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

Added in version 3.6.2.

make touch 빌드 대상 제거

수정 시간을 갱신하여 생성된 파일의 묵시적 재생성을 요청하는 데 이전에 사용된 make touch 빌드 대상이 제거되었습니다.

새로운 make regen-all 대상으로 대체되었습니다.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

버전 3.6.2에서 변경.

파이썬 3.6.4의 주목할만한 변경 사항

공용 API의 일부였던 PyExc_RecursionErrorInst 싱글톤은 멤버가 삭제되지 않아서 인터프리터 종료 중에 세그멘테이션 오류가 발생할 수 있어서 제거되었습니다. (Contributed by Xavier de Gaye in bpo-22898 [https://bugs.python.org/issue?@action=redirect&bpo=22898] and bpo-30697 [https://bugs.python.org/issue?@action=redirect&bpo=30697].)

파이썬 3.6.5의 주목할만한 변경 사항

이제 locale.localeconv() 함수는 때에 따라 임시로 LC_CTYPE 로케일을 LC_NUMERIC 로케일로 설정합니다. (Contributed by Victor Stinner in bpo-31900 [https://bugs.python.org/issue?@action=redirect&bpo=31900].)

파이썬 3.6.7의 주목할만한 변경 사항

xml.dom.minidom and xml.sax modules no longer process external entities by default. See also gh-61441 [https://github.com/python/cpython/issues/61441].

3.6.7에서 tokenize 모듈은 이제 후행 줄 넘김이 없는 입력이 제공될 때 묵시적으로 NEWLINE 토큰을 내보냅니다. 이 동작은 이제 C 토크나이저가 내부적으로 수행하는 작업과 일치합니다. (Contributed by Ammar Askar in bpo-33899 [https://bugs.python.org/issue?@action=redirect&bpo=33899].)

파이썬 3.6.10의 주목할만한 변경 사항

심각한 보안 문제로 인해 asyncio.loop.create_datagram_endpoint()의 reuse_address 매개 변수는 더는 지원되지 않습니다. 이는 UDP에서 소켓 옵션 SO_REUSEADDR의 동작 때문입니다. 자세한 내용은 loop.create_datagram_endpoint() 설명서를 참조하십시오. (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228].)

파이썬 3.6.13의 주목할만한 변경 사항

Earlier Python versions allowed using both ; and & as query parameter separators in urllib.parse.parse_qs() and urllib.parse.parse_qsl(). Due to security concerns, and to conform with newer W3C recommendations, this has been changed to allow only a single separator key, with & as the default. This change also affects cgi.parse() and cgi.parse_multipart() as they use the affected functions internally. For more details, please see their respective documentation. (Contributed by Adam Goldschmidt, Senthil Kumaran and Ken Jin in bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967].)

Notable changes in Python 3.6.14

A security fix alters the ftplib.FTP behavior to not trust the IPv4 address sent from the remote server when setting up a passive data channel. We reuse the ftp server IP address instead. For unusual code requiring the old behavior, set a trust_server_pasv_ipv4_address attribute on your FTP instance to True. (See gh-87451 [https://github.com/python/cpython/issues/87451])

The presence of newline or tab characters in parts of a URL allows for some forms of attacks. Following the WHATWG specification that updates RFC 3986, ASCII newline \n, \r and tab \t characters are stripped from the URL by the parser urllib.parse() preventing such attacks. The removal characters are controlled by a new module level variable urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE. (See gh-88048 [https://github.com/python/cpython/issues/88048])

파이썬 3.5의 새로운 기능

편집자:

Elvis Pranskevichus <elvis@magic.io>, Yury Selivanov <yury@magic.io>

이 기사에서는 3.4과 비교하여 파이썬 3.5의 새로운 기능에 관해 설명합니다. 파이썬 3.5는 2015년 9월 13일에 출시되었습니다. 전체 변경 사항 목록은 changelog [https://docs.python.org/3.5/whatsnew/changelog.html]를 참조하십시오.

더 보기

PEP 478 [https://peps.python.org/pep-0478/] - 파이썬 3.5 출시 일정

요약 – 배포 주요 사항

새로운 문법 기능:

PEP 492, async와 await 구문을 사용하는 코루틴.

PEP 465, 새로운 행렬 곱셈 연산자: a @ b.

PEP 448, 추가적인 언 패킹 일반화.

새로운 라이브러리 모듈:

typing: PEP 484 – 형 힌트.

zipapp: PEP 441 파이썬 ZIP 응용 프로그램 지원 개선.

새로운 내장 기능:

bytes % args, bytearray % args : PEP 461 – bytes와 bytearray에 % 포매팅 추가.

새로운 bytes.hex(), bytearray.hex() 및 memoryview.hex() 메서드. (Contributed by Arnon Yaari in bpo-9951 [https://bugs.python.org/issue?@action=redirect&bpo=9951].)

memoryview는 이제 튜플 인덱싱(다차원 포함)을 지원합니다. (Contributed by Antoine Pitrou in bpo-23632 [https://bugs.python.org/issue?@action=redirect&bpo=23632].)

제너레이터에는 yield from 표현식에 의해 이터레이션 중인 객체를 반환하는 새로운 gi_yieldfrom 어트리뷰트가 있습니다. (Contributed by Benno Leslie and Yury Selivanov in bpo-24450 [https://bugs.python.org/issue?@action=redirect&bpo=24450].)

이제 최대 재귀 깊이에 도달하면 새로운 RecursionError 예외가 발생합니다. (Contributed by Georg Brandl in bpo-19235 [https://bugs.python.org/issue?@action=redirect&bpo=19235].)

CPython 구현 개선:

LC_TYPE 로케일이 POSIX 로케일(C 로케일)일 때, sys.stdin과 sys.stdout은 이제 strict 에러 처리기 대신 surrogateescape 에러 처리기를 사용합니다. (Contributed by Victor Stinner in bpo-19977 [https://bugs.python.org/issue?@action=redirect&bpo=19977].)

.pyo 파일은 더는 사용되지 않으며 .pyc 이름에 명시적으로 최적화 수준을 포함하는 더 유연한 체계로 대체되었습니다. (PEP 488 개요를 참조하십시오.)

내장과 확장 모듈은 이제 파이썬 모듈이 로드되는 방식과 유사한 다단계 절차로 초기화됩니다. (PEP 489 개요를 참조하십시오.)

표준 라이브러리의 현저한 개선:

collections.OrderedDict는 이제 C로 구현되어서 4 에서 100배 더 빠릅니다.

ssl 모듈은 네트워크 IO에서 SSL 프로토콜 처리를 분리하는 메모리 BIO 지원을 얻었습니다.

새로운 os.scandir() 함수는 디렉터리 순회의 더 좋고 훨씬 더 빠른 방법을 제공합니다.

functools.lru_cache()는 대부분 C로 재구현되어서 훨씬 더 나은 성능을 제공합니다.

새로운 subprocess.run() 함수는 서브 프로세스를 실행하는 간소화된 방법을 제공합니다.

traceback 모듈은 향상된 성능과 개발자 편의를 위해 크게 개선되었습니다.

보안 향상:

SSLv3은 이제 표준 라이브러리 전체에서 비활성화됩니다. ssl.SSLContext를 수동으로 인스턴스 화하여 여전히 활성화 할 수 있습니다. (자세한 내용은 bpo-22638 [https://bugs.python.org/issue?@action=redirect&bpo=22638]을 참조하십시오; 이 변경 사항은 CPython 3.4와 2.7로 역 이식되었습니다.)

HTTP 쿠키 구문 분석은 이제 잠재적인 주입 공격으로부터 보호하기 위해 더 엄격해졌습니다. (Contributed by Antoine Pitrou in bpo-22796 [https://bugs.python.org/issue?@action=redirect&bpo=22796].)

윈도우 개선:

윈도우 용 새 설치 프로그램이 이전 MSI를 대체했습니다. 자세한 정보는 윈도우에서 파이썬 사용하기를 참조하십시오.

윈도우 빌드는 이제 Microsoft Visual C++ 14.0을 사용하고, 확장 모듈은 같은 것을 사용해야 합니다.

다른 많은 소규모 개선 사항, CPython 최적화, 폐지 및 잠재적 이식 문제를 포함하여, 사용자가 직면하는 변경 사항의 포괄적인 목록을 읽으십시오.

새로운 기능

PEP 492 - async와 await 구문을 사용하는 코루틴

PEP 492 [https://peps.python.org/pep-0492/]는 어웨이터블 객체, 코루틴 함수, 비동기 이터레이션 및 비동기 컨텍스트 관리자를 추가하여 파이썬에서 비동기 프로그래밍에 대한 지원을 크게 향상합니다.

코루틴 함수는 새로운 async def 구문을 사용하여 선언됩니다:

>>> async def coro():
...     return 'spam'

코루틴 함수 내에서 새로운 await 표현식을 사용하여 결과를 사용할 수 있을 때까지 코루틴 실행을 중단 할 수 있습니다. __await__() 메서드를 정의하여 어웨이터블 프로토콜을 구현하는 한 모든 객체는 await 될 수 있습니다.

PEP 492는 또한 비동기 이터러블에 대한 편리한 이터레이션을 위해 async for 문을 추가합니다.

새로운 구문을 사용하여 작성된 기본 HTTP 클라이언트의 예:

import asyncio

async def http_get(domain):
    reader, writer = await asyncio.open_connection(domain, 80)

    writer.write(b'\r\n'.join([
        b'GET / HTTP/1.1',
        b'Host: %b' % domain.encode('latin-1'),
        b'Connection: close',
        b'', b''
    ]))

    async for line in reader:
        print('>>>', line)

    writer.close()

loop = asyncio.get_event_loop()
try:
    loop.run_until_complete(http_get('example.com'))
finally:
    loop.close()

비동기 이터레이션과 마찬가지로, 비동기 컨텍스트 관리자를 위한 새로운 구문이 있습니다. 다음 스크립트:

import asyncio

async def coro(name, lock):
    print('coro {}: waiting for lock'.format(name))
    async with lock:
        print('coro {}: holding the lock'.format(name))
        await asyncio.sleep(1)
        print('coro {}: releasing the lock'.format(name))

loop = asyncio.get_event_loop()
lock = asyncio.Lock()
coros = asyncio.gather(coro(1, lock), coro(2, lock))
try:
    loop.run_until_complete(coros)
finally:
    loop.close()

는 다음을 출력합니다:

coro 2: waiting for lock
coro 2: holding the lock
coro 1: waiting for lock
coro 2: releasing the lock
coro 1: holding the lock
coro 1: releasing the lock

async for와 async with는 모두 async def로 선언된 코루틴 함수 내에서만 사용할 수 있음에 유의하십시오.

코루틴 함수는 asyncio loop와 같은 호환 가능한 이벤트 루프 내에서 실행되도록 설계되었습니다.

참고

버전 3.5.2에서 변경: CPython 3.5.2부터 __aiter__는 비동기 이터레이터를 직접 반환 할 수 있습니다. 어웨이터블 객체를 반환하면 PendingDeprecationWarning 이 발생합니다.

비동기 이터레이터(Asynchronous Iterators) 설명서 섹션에서 자세한 내용을 참조하십시오.

더 보기

PEP 492 [https://peps.python.org/pep-0492/] – async와 await 구문을 사용하는 코루틴

Yury Selivanov가 작성하고 구현한 PEP.

PEP 465 - 행렬 곱셈을 위한 전용 중위(infix) 연산자

PEP 465 [https://peps.python.org/pep-0465/]는 행렬 곱셈을 위한 @ 중위(infix) 연산자를 추가합니다. 현재, 내장 파이썬 형은 어느 것도 새 연산자를 구현하지 않지만, 일반, 뒤집힌 및 증분 행렬 곱셈에 대해 __matmul__(), __rmatmul__() 및 __imatmul__()를 정의하여 구현할 수 있습니다. 이러한 메서드의 의미는 다른 중위 산술 연산자를 정의하는 메서드의 의미와 유사합니다.

행렬 곱셈은 수학, 과학, 공학의 많은 분야에서 매우 일반적인 연산이며, @를 추가하면 더 깨끗한 코드를 작성할 수 있습니다:

S = (H @ beta - r).T @ inv(H @ V @ H.T) @ (H @ beta - r)

이렇게 작성하는 대신에:

S = dot((dot(H, beta) - r).T,
        dot(inv(dot(dot(H, V), H.T)), dot(H, beta) - r))

NumPy 1.10은 새 연산자를 지원합니다:

>>> import numpy

>>> x = numpy.ones(3)
>>> x
array([ 1., 1., 1.])

>>> m = numpy.eye(3)
>>> m
array([[ 1., 0., 0.],
       [ 0., 1., 0.],
       [ 0., 0., 1.]])

>>> x @ m
array([ 1., 1., 1.])

더 보기

PEP 465 [https://peps.python.org/pep-0465/] – 행렬 곱셈을 위한 전용 중위(infix) 연산자

Nathaniel J. Smith가 작성한 PEP; Benjamin Peterson이 구현했습니다.

PEP 448 - 추가적인 언 패킹 일반화

PEP 448 [https://peps.python.org/pep-0448/]은 * 이터러블 언 패킹 연산자와 ** 딕셔너리 언 패킹 연산자의 허용된 사용을 확장합니다. 이제 함수 호출에서 임의의 수의 언 패킹을 사용할 수 있습니다:

>>> print(*[1], *[2], 3, *[4, 5])
1 2 3 4 5

>>> def fn(a, b, c, d):
...     print(a, b, c, d)
...

>>> fn(**{'a': 1, 'c': 3}, **{'b': 2, 'd': 4})
1 2 3 4

마찬가지로, 튜플, 리스트, 집합 및 딕셔너리 디스플레이는 여러 번의 언 패킹을 허용합니다 (표현식 목록(Expression lists)과 딕셔너리 디스플레이를 참조하십시오):

>>> *range(4), 4
(0, 1, 2, 3, 4)

>>> [*range(4), 4]
[0, 1, 2, 3, 4]

>>> {*range(4), 4, *(5, 6, 7)}
{0, 1, 2, 3, 4, 5, 6, 7}

>>> {'x': 1, **{'y': 2}}
{'x': 1, 'y': 2}

더 보기

PEP 448 [https://peps.python.org/pep-0448/] – 추가적인 언 패킹 일반화

Joshua Landau가 작성한 PEP; Neil Girdhar, Thomas Wouters 및 Joshua Landau가 구현했습니다.

PEP 461 - bytes와 bytearray를 위한 퍼센트 포매팅 지원

PEP 461 [https://peps.python.org/pep-0461/]은 bytes와 bytearray에 % 보간 연산자에 대한 지원을 추가합니다.

보간은 일반적으로 문자열 연산으로 간주하지만, bytes나 bytearrays에 대한 보간이 적절한 경우가 있고, 이 누락 된 기능을 보완하는 데 필요한 작업이 코드의 전반적인 가독성을 떨어뜨립니다. 이 문제는 종종 바이너리와 ASCII 호환 텍스트가 혼합된 전송 형식(wire format) 프로토콜을 다룰 때 특히 중요합니다.

예:

>>> b'Hello %b!' % b'World'
b'Hello World!'

>>> b'x=%i y=%f' % (1, 2.5)
b'x=1 y=2.500000'

유니코드는 %b에 허용되지 않지만, %a에서 허용됩니다 (repr(obj).encode('ascii', 'backslashreplace')와 동등합니다):

>>> b'Hello %b!' % 'World'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: %b requires bytes, or an object that implements __bytes__, not 'str'

>>> b'price: %a' % '10€'
b"price: '10\\u20ac'"

%s와 %r 변환 유형은, 지원되기는 하지만, 파이썬 2와의 호환성이 필요한 코드 베이스에서만 사용해야 함에 유의하십시오.

더 보기

PEP 461 [https://peps.python.org/pep-0461/] – bytes와 bytearray에 % 포매팅 추가

Ethan Furman이 작성한 PEP; Neil Schemenauer와 Ethan Furman이 구현했습니다.

PEP 484 - 형 힌트

함수 어노테이션 구문은 버전 3.0(PEP 3107 [https://peps.python.org/pep-3107/])부터 파이썬 기능이었지만, 어노테이션의 의미는 정의되지 않은 상태로 남아 있었습니다.

경험에 따르면 대부분 함수 어노테이션은 함수 매개 변수와 반환 값에 형 힌트를 제공하는 데 사용되었습니다. 표준 라이브러리에 형 어노테이션을 위한 기본 정의와 도구가 포함되어 있다면 파이썬 사용자에게 도움이 될 것이 분명해졌습니다.

PEP 484 [https://peps.python.org/pep-0484/]는 어노테이션을 사용할 수 없는 상황에 대한 몇 가지 규칙과 함께 이러한 표준 정의와 도구를 제공하는 잠정적 모듈을 도입합니다.

예를 들어, 다음은 어노테이션에 인자와 반환형이 선언된 간단한 함수입니다:

def greeting(name: str) -> str:
    return 'Hello ' + name

While these annotations are available at runtime through the usual __annotations__ attribute, no automatic type checking happens at runtime. Instead, it is assumed that a separate off-line type checker (e.g. mypy [https://mypy-lang.org]) will be used for on-demand source code analysis.

형 시스템은 공용체(unions), 제네릭 형 및 모든 형과 일치하는 (즉, 대입 가능한) Any라는 특수형을 지원합니다.

더 보기

typing 모듈 설명서

PEP 484 [https://peps.python.org/pep-0484/] – 형 힌트

Guido van Rossum, Jukka Lehtosalo 및 Łukasz Langa가 작성한 PEP; Guido van Rossum이 구현했습니다.

PEP 483 [https://peps.python.org/pep-0483/] – 형 힌트 이론

Guido van Rossum이 작성한 PEP

PEP 471 - os.scandir() 함수 – 더 빠르고 더 나은 디렉터리 이터레이터

PEP 471 [https://peps.python.org/pep-0471/]은 표준 라이브러리에 새 디렉터리 이터레이션 함수 os.scandir()을 추가합니다. 또한, os.walk()는 이제 scandir을 사용하여 구현되어, POSIX 시스템에서는 3 에서 5배, 윈도우 시스템에서는 7 에서 20배 더 빠릅니다. 이것은 주로 디렉터리 트리를 탐색하는 데 필요한 os.stat() 호출 수를 크게 줄임으로써 달성됩니다.

또한, scandir은 파일 이름 리스트 대신에 이터레이터를 반환하므로, 매우 큰 디렉터리를 이터레이션 할 때 메모리 효율성이 향상됩니다.

다음 예제는 '.'로 시작하지 않는 지정된 path의 모든 파일(디렉터리 제외)을 표시하기 위해 os.scandir()을 사용하는 간단한 방법을 보여줍니다. entry.is_file() 호출은 일반적으로 추가 시스템 호출을 수행하지 않습니다:

for entry in os.scandir(path):
    if not entry.name.startswith('.') and entry.is_file():
        print(entry.name)

더 보기

PEP 471 [https://peps.python.org/pep-0471/] – os.scandir() 함수 – 더 빠르고 더 나은 디렉터리 이터레이터

Victor Stinner의 도움으로 Ben Hoyt가 작성하고 구현한 PEP.

PEP 475: EINTR로 실패한 시스템 호출 재시도

An errno.EINTR error code is returned whenever a system call, that is waiting for I/O, is interrupted by a signal. Previously, Python would raise InterruptedError in such cases. This meant that, when writing a Python application, the developer had two choices:

InterruptedError를 무시합니다.

InterruptedError를 처리하고 모든 호출 지점에서 중단된 시스템 호출을 다시 시작합니다.

첫 번째 옵션은 응용 프로그램이 간헐적으로 실패하도록 합니다. 두 번째 옵션은 코드를 거의 읽을 수 없게 만드는 많은 양의 상용구를 추가합니다. 다음을 비교해 보십시오:

print("Hello World")

와:

while True:
    try:
        print("Hello World")
        break
    except InterruptedError:
        continue

PEP 475 [https://peps.python.org/pep-0475/]는 EINTR에서 시스템 호출의 자동 재시도를 구현합니다. 이것은 대부분의 상황에서 사용자 코드에서 EINTR이나 InterruptedError를 다루는 부담을 제거하고 표준 라이브러리를 포함한 파이썬 프로그램을 더욱 강인하게 만듭니다. 시스템 호출은 시그널 처리기가 예외를 발생시키지 않는 경우에만 재시도됨에 유의하십시오.

다음은 시그널에 의해 중단될 때 재시도되는 함수 목록입니다:

open()과 io.open();

faulthandler 모듈의 함수들;

os 함수: fchdir(), fchmod(), fchown(), fdatasync(), fstat(), fstatvfs(), fsync(), ftruncate(), mkfifo(), mknod(), open(), posix_fadvise(), posix_fallocate(), pread(), pwrite(), read(), readv(), sendfile(), wait3(), wait4(), wait(), waitid(), waitpid(), write(), writev();

special cases: os.close() and os.dup2() now ignore EINTR errors; the syscall is not retried (see the PEP for the rationale);

select 함수: devpoll.poll(), epoll.poll(), kqueue.control(), poll.poll(), select();

socket 클래스의 메서드: accept(), connect() (비 블로킹 소켓 제외), recv(), recvfrom(), recvmsg(), send(), sendall(), sendmsg(), sendto();

signal.sigtimedwait()와 signal.sigwaitinfo();

time.sleep().

더 보기

PEP 475 [https://peps.python.org/pep-0475/] – EINTR로 실패한 시스템 호출 재시도

Charles-François Natali와 Victor Stinner가 Antoine Pitrou의 도움을 받아 PEP와 구현을 작성했습니다 (프렌치 커넥션).

PEP 479: 제너레이터 내부에서의 StopIteration 처리 변경

파이썬 3.4와 이전 버전에서 제너레이터와 StopIteration의 상호 작용은 때때로 놀랍고, 모호한 버그를 감출 수 있습니다. 이전에는, 제너레이터 함수 내에서 실수로 발생한 StopIteration이 제너레이터를 구동하는 루프 구성에 의해 이터레이션의 끝으로 해석되었습니다.

PEP 479 [https://peps.python.org/pep-0479/]는 제너레이터의 동작을 변경합니다: 제너레이터 내부에서 StopIteration 예외가 발생하면, 제너레이터 프레임을 종료하기 전에 RuntimeError로 대체됩니다. 이 변경의 주요 목표는 보호되지 않는 next() 호출이 StopIteration을 발생시키고 이 때문에 제너레이터가 제어하는 이터레이션이 조용히 종료되도록 하는 상황에서 디버깅을 용이하게 하는 것입니다. 이것은 yield from 구조와 결합할 때 특히 유해합니다.

이는 이전 버전과 호환되지 않는 변경이므로, 새 동작을 사용하려면 __future__ 임포트가 필요합니다:

>>> from __future__ import generator_stop

>>> def gen():
...     next(iter([]))
...     yield
...
>>> next(gen())
Traceback (most recent call last):
  File "<stdin>", line 2, in gen
StopIteration

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: generator raised StopIteration

__future__ 임포트가 없으면, 제너레이터 내에서 StopIteration 예외가 발생할 때마다 PendingDeprecationWarning 이 발생합니다.

더 보기

PEP 479 [https://peps.python.org/pep-0479/] – 제너레이터 내부에서의 StopIteration 처리 변경

Chris Angelico와 Guido van Rossum이 작성한 PEP. Chris Angelico, Yury Selivanov 및 Nick Coghlan이 구현했습니다.

PEP 485: 대략적인 동등성을 테스트하는 함수

PEP 485 [https://peps.python.org/pep-0485/]는 두 값이 대략 같거나 서로 “가까운”지를 알려주는 math.isclose()와 cmath.isclose() 함수를 추가합니다. 두 값이 가까운 것으로 간주하는지는 주어진 절대와 상대 허용 오차에 따라 결정됩니다. 상대적 허용 오차는 더 큰 절댓값에 상대적으로 isclose 인자간에 허용되는 최대 차이입니다:

>>> import math
>>> a = 5.0
>>> b = 4.99998
>>> math.isclose(a, b, rel_tol=1e-5)
True
>>> math.isclose(a, b, rel_tol=1e-6)
False

절대 허용 오차를 사용하여 두 값을 비교할 수도 있습니다. 이 값은 음수가 아니어야 합니다:

>>> import math
>>> a = 5.0
>>> b = 4.99998
>>> math.isclose(a, b, abs_tol=0.00003)
True
>>> math.isclose(a, b, abs_tol=0.00001)
False

더 보기

PEP 485 [https://peps.python.org/pep-0485/] – 대략적인 동등성을 테스트하는 함수

Christopher Barker가 작성한 PEP; Chris Barker와 Tal Einat이 구현했습니다.

PEP 486: 파이썬 런처가 가상 환경을 인식하도록 만들기

PEP 486 [https://peps.python.org/pep-0486/]은 윈도우 런처(PEP 397 [https://peps.python.org/pep-0397/]을 참조하십시오)가 활성 가상 환경을 인식하도록 합니다. 기본 인터프리터를 사용하고 VIRTUAL_ENV 환경 변수를 설정하면, 가상 환경의 인터프리터가 사용됩니다.

더 보기

PEP 486 [https://peps.python.org/pep-0486/] – 파이썬 런처가 가상 환경을 인식하도록 만들기

Paul Moore가 작성하고 구현한 PEP.

PEP 488: PYO 파일 제거

PEP 488 [https://peps.python.org/pep-0488/]은 .pyo 파일의 개념을 제거합니다. 이는 .pyc 파일이 최적화되지 않은 바이트 코드와 최적화된 바이트 코드를 모두 나타냄을 의미합니다. 바이트 코드 파일을 지속해서 재생성할 필요가 없도록, .pyc 파일은 이제 바이트 코드가 최적화될 때 이름에 선택적 opt- 태그를 갖습니다. 이것은 -O나 -OO에서 실행할 때 더는 바이트 코드 파일 이름 충돌이 발생하지 않는 부작용이 있습니다. 따라서, -O와 -OO에서 생성된 바이트 코드 파일이 이제 동시에 존재할 수 있습니다. importlib.util.cache_from_source()는 이러한 변경을 돕기 위해 갱신된 API를 갖습니다.

더 보기

PEP 488 [https://peps.python.org/pep-0488/] – PYO 파일 제거

Brett Cannon이 작성하고 구현한 PEP.

PEP 489: 다단계 확장 모듈 초기화

PEP 489 [https://peps.python.org/pep-0489/]는 파이썬 3.4에서 PEP 451 [https://peps.python.org/pep-0451/]이 도입한 2단계 모듈 로딩 메커니즘을 활용하기 위해 확장 모듈 초기화를 갱신합니다.

이 변경으로 인해 ASCII로 제한되지 않고 유효한 식별자를 모듈 이름으로 사용할 수 있는 기능을 포함하여, 확장 모듈의 임포트 의미 체계가 파이썬 소스와 바이트 코드 모듈의 것과 훨씬 더 가까운 새로운 메커니즘을 사용하도록 옵트 인합니다.

더 보기

PEP 489 [https://peps.python.org/pep-0489/] – 다단계 확장 모듈 초기화

Petr Viktorin, Stefan Behnel 및 Nick Coghlan이 작성한 PEP; Petr Viktorin이 구현했습니다.

기타 언어 변경

핵심 파이썬 언어에 대한 몇 가지 작은 변경 사항은 다음과 같습니다:

"namereplace" 에러 처리기를 추가했습니다. 이제 "backslashreplace" 에러 처리기가 디코딩과 변환에서 작동합니다. (Contributed by Serhiy Storchaka in bpo-19676 [https://bugs.python.org/issue?@action=redirect&bpo=19676] and bpo-22286 [https://bugs.python.org/issue?@action=redirect&bpo=22286].)

-b 옵션은 이제 bytes와 int의 비교에 영향을 줍니다. (Contributed by Serhiy Storchaka in bpo-23681 [https://bugs.python.org/issue?@action=redirect&bpo=23681].)

새로운 카자흐어 kz1048과 타지크어 koi8_t 코덱. (Contributed by Serhiy Storchaka in bpo-22682 [https://bugs.python.org/issue?@action=redirect&bpo=22682] and bpo-22681 [https://bugs.python.org/issue?@action=redirect&bpo=22681].)

프로퍼티 독스트링은 이제 쓰기 가능합니다. 이것은 collections.namedtuple() 독스트링에 특히 유용합니다. (Contributed by Berker Peksag in bpo-24064 [https://bugs.python.org/issue?@action=redirect&bpo=24064].)

이제 상대 임포트를 포함하는 순환 임포트가 지원됩니다. (Contributed by Brett Cannon and Antoine Pitrou in bpo-17636 [https://bugs.python.org/issue?@action=redirect&bpo=17636].)

새로운 모듈

typing

새로운 typing 잠정적 모듈은 함수 형 어노테이션에 대한 표준 정의와 도구를 제공합니다. 자세한 내용은 형 힌트를 참조하십시오.

zipapp

새로운 (PEP 441 [https://peps.python.org/pep-0441/]에서 지정된) zipapp 모듈은 실행 가능한 파이썬 Zip 응용 프로그램을 만들기 위한 API와 명령 줄 도구를 제공합니다. 실행 가능한 파이썬 Zip 응용 프로그램은 bpo-1739468 [https://bugs.python.org/issue?@action=redirect&bpo=1739468]에서 파이썬 2.6에 도입되었지만, 그때나 그 이후로 잘 공개되지 않았습니다.

새로운 모듈을 사용하면, __main__.py 파일을 포함한 모든 파일을 myapp 디렉터리에 넣고 다음을 실행하는 것만큼 간단하게 응용 프로그램을 번들링 할 수 있습니다:

$ python -m zipapp myapp
$ python myapp.pyz

모듈 구현은 bpo-23491 [https://bugs.python.org/issue?@action=redirect&bpo=23491]에서 Paul Moore에 의해 기고되었습니다.

더 보기

PEP 441 [https://peps.python.org/pep-0441/] – 파이썬 ZIP 응용 프로그램 지원 개선

개선된 모듈

argparse

ArgumentParser 클래스는 이제 allow_abbrev를 False로 설정하여 긴 옵션의 약어 사용을 비활성화 할 수 있습니다. (Contributed by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson in bpo-14910 [https://bugs.python.org/issue?@action=redirect&bpo=14910].)

asyncio

asyncio 모듈은 잠정적이므로, 파이썬 3.5에 도입된 모든 변경 사항은 파이썬 3.4.x로 역 이식되었습니다.

파이썬 3.4.0 이후 asyncio 모듈의 주목할만한 변경 사항:

새로운 디버깅 API: loop.set_debug()와 loop.get_debug() 메서드. (Contributed by Victor Stinner.)

프로액터(proactor) 이벤트 루프는 이제 SSL을 지원합니다. (Contributed by Antoine Pitrou and Victor Stinner in bpo-22560 [https://bugs.python.org/issue?@action=redirect&bpo=22560].)

이벤트 루프가 닫혔는지 확인하는 새로운 loop.is_closed() 메서드. (Contributed by Victor Stinner in bpo-21326 [https://bugs.python.org/issue?@action=redirect&bpo=21326].)

코루틴을 위한 새로운 Task를 편리하게 만들고 예약하는 새로운 loop.create_task(). create_task 메서드는 코루틴을 태스크로 감싸는 모든 asyncio 함수(가령 asyncio.wait(), asyncio.gather() 등)에서도 사용됩니다. (Contributed by Victor Stinner.)

흐름 제어의 high-와 low- 수위 한계를 조회하는 새로운 transport.get_write_buffer_limits() 메서드. (Contributed by Victor Stinner.)

async() 함수는 폐지되었고 ensure_future()로 대체합니다. (Contributed by Yury Selivanov.)

loop.create_task() 메서드가 사용하는 태스크 팩토리를 사용자 정의하는 새로운 loop.set_task_factory()와 loop.get_task_factory() 메서드. (Contributed by Yury Selivanov.)

새로운 Queue.join()과 Queue.task_done() 큐 메서드. (Contributed by Victor Stinner.)

JoinableQueue 클래스가 제거되고, asyncio.Queue 클래스로 대체되었습니다. (Contributed by Victor Stinner.)

3.5.1의 업데이트:

ensure_future() 함수와 이를 사용하는 모든 함수(가령 loop.run_until_complete())는 이제 모든 종류의 어웨이터블 객체를 받아들입니다. (Contributed by Yury Selivanov.)

다른 스레드의 이벤트 루프에 코루틴을 제출하는 새로운 run_coroutine_threadsafe() 함수. (Contributed by Vincent Michel.)

트랜스포트가 닫히고 있거나 닫혀 있는지 확인하는 새로운 Transport.is_closing() 메서드. (Contributed by Yury Selivanov.)

loop.create_server() 메서드는 이제 호스트 리스트를 받아들일 수 있습니다. (Contributed by Yann Sionneau.)

3.5.2의 업데이트 :

Future 객체를 만드는 새로운 loop.create_future() 메서드. 이를 통해 uvloop [https://github.com/MagicStack/uvloop]와 같은 대체 이벤트 루프 구현이 더 빠른 asyncio.Future 구현을 제공 할 수 있습니다. (Contributed by Yury Selivanov.)

현재 예외 처리기를 가져오는 새로운 loop.get_exception_handler() 메서드. (Contributed by Yury Selivanov.)

구분자 바이트 시퀀스가 나타날 때까지 스트림에서 데이터를 읽는 새로운 StreamReader.readuntil() 메서드. (Contributed by Mark Korenberg.)

loop.create_connection()과 loop.create_server() 메서드는 주소가 이미 결정된 경우 시스템 getaddrinfo 함수를 호출하지 않도록 최적화되었습니다. (Contributed by A. Jesse Jiryu Davis.)

loop.sock_connect(sock, address)는 더는 호출 전에 address를 결정할 필요가 없습니다. (Contributed by A. Jesse Jiryu Davis.)

bz2

이제 BZ2Decompressor.decompress 메서드는 압축 해제된 데이터의 최대 크기를 제한하기 위해 선택적 max_length 인자를 받아들입니다. (Contributed by Nikolaus Rath in bpo-15955 [https://bugs.python.org/issue?@action=redirect&bpo=15955].)

cgi

The FieldStorage class now supports the context manager protocol. (Contributed by Berker Peksag in bpo-20289 [https://bugs.python.org/issue?@action=redirect&bpo=20289].)

cmath

새로운 함수 isclose()는 대략적인 동등성을 테스트하는 방법을 제공합니다. (Contributed by Chris Barker and Tal Einat in bpo-24270 [https://bugs.python.org/issue?@action=redirect&bpo=24270].)

code

InteractiveInterpreter.showtraceback() 메서드는 이제 대화 형 인터프리터처럼 전체 연결된(chained) 트레이스백을 인쇄합니다. (Contributed by Claudiu Popa in bpo-17442 [https://bugs.python.org/issue?@action=redirect&bpo=17442].)

collections

OrderedDict 클래스는 이제 C로 구현되어 4 에서 100배 더 빨라졌습니다. (Contributed by Eric Snow in bpo-16991 [https://bugs.python.org/issue?@action=redirect&bpo=16991].)

OrderedDict.items(), OrderedDict.keys(), OrderedDict.values() 뷰는 이제 reversed() 이터레이션을 지원합니다. (Contributed by Serhiy Storchaka in bpo-19505 [https://bugs.python.org/issue?@action=redirect&bpo=19505].)

deque 클래스는 이제 index(), insert() 및 copy()를 정의하고, +와 * 연산자를 지원합니다. 이를 통해 데크가 MutableSequence로 인식되고 리스트에 대한 대체 가능성이 향상됩니다. (Contributed by Raymond Hettinger in bpo-23704 [https://bugs.python.org/issue?@action=redirect&bpo=23704].)

이제 namedtuple()이 생성한 독스트링을 갱신할 수 있습니다:

Point = namedtuple('Point', ['x', 'y'])
Point.__doc__ += ': Cartesian coordinate'
Point.x.__doc__ = 'abscissa'
Point.y.__doc__ = 'ordinate'

(Contributed by Berker Peksag in bpo-24064 [https://bugs.python.org/issue?@action=redirect&bpo=24064].)

UserString 클래스는 이제 str의 해당 메서드와 일치하도록 __getnewargs__(), __rmod__(), casefold(), format_map(), isprintable() 및 maketrans() 메서드를 구현합니다. (Contributed by Joe Jevnik in bpo-22189 [https://bugs.python.org/issue?@action=redirect&bpo=22189].)

collections.abc

Sequence.index() 메서드는 이제 tuple, list 등의 해당 메서드와 일치하도록 start와 stop 인자를 받아들입니다 (Contributed by Devin Jeanpierre in bpo-23086 [https://bugs.python.org/issue?@action=redirect&bpo=23086].)

새로운 Generator 추상 베이스 클래스. (Contributed by Stefan Behnel in bpo-24018 [https://bugs.python.org/issue?@action=redirect&bpo=24018].)

새로운 Awaitable, Coroutine, AsyncIterator 및 AsyncIterable 추상 베이스 클래스. (Contributed by Yury Selivanov in bpo-24184 [https://bugs.python.org/issue?@action=redirect&bpo=24184].)

For earlier Python versions, a backport of the new ABCs is available in an external PyPI package [https://pypi.org/project/backports_abc/].

compileall

새로운 compileall 옵션인 -j N 을 사용하면 N 작업자를 동시에 실행하여 병렬 바이트 코드 컴파일을 수행할 수 있습니다. compile_dir() 함수에는 대응하는 workers 매개 변수가 있습니다. (Contributed by Claudiu Popa in bpo-16104 [https://bugs.python.org/issue?@action=redirect&bpo=16104].)

또 다른 새로운 옵션인 -r은 하위 디렉터리에 대한 최대 재귀 수준을 제어할 수 있습니다. (Contributed by Claudiu Popa in bpo-19628 [https://bugs.python.org/issue?@action=redirect&bpo=19628].)

이제 -q 명령 줄 옵션을 두 번 이상 지정할 수 있으며, 이 경우 에러를 포함한 모든 출력이 억제됩니다. compile_dir(), compile_file() 및 compile_path()의 해당 quiet 매개 변수는 이제 출력 억제 수준을 나타내는 정숫값을 받아들일 수 있습니다. (Contributed by Thomas Kluyver in bpo-21338 [https://bugs.python.org/issue?@action=redirect&bpo=21338].)

concurrent.futures

Executor.map() 메서드는 이제 chunksize 인자를 받아, ProcessPoolExecutor()가 사용될 때 작업을 일괄 처리하여 성능을 향상할 수 있습니다. (Contributed by Dan O’Reilly in bpo-11271 [https://bugs.python.org/issue?@action=redirect&bpo=11271].)

ThreadPoolExecutor 생성자의 작업자 수는 이제 선택 사항입니다. 기본값은 CPU 수의 5배입니다. (Contributed by Claudiu Popa in bpo-21527 [https://bugs.python.org/issue?@action=redirect&bpo=21527].)

configparser

configparser는 이제 ConfigParser 생성자에서 변환기 딕셔너리를 지정하거나 ConfigParser 서브 클래스에서 메서드로 정의하여 값 변환을 사용자 정의하는 방법을 제공합니다. 구문 분석기 인스턴스에 정의된 변환기는 섹션 프락시에 의해 상속됩니다.

예:

>>> import configparser
>>> conv = {}
>>> conv['list'] = lambda v: [e.strip() for e in v.split() if e.strip()]
>>> cfg = configparser.ConfigParser(converters=conv)
>>> cfg.read_string("""
... [s]
... list = a b c d e f g
... """)
>>> cfg.get('s', 'list')
'a b c d e f g'
>>> cfg.getlist('s', 'list')
['a', 'b', 'c', 'd', 'e', 'f', 'g']
>>> section = cfg['s']
>>> section.getlist('list')
['a', 'b', 'c', 'd', 'e', 'f', 'g']

(Contributed by Łukasz Langa in bpo-18159 [https://bugs.python.org/issue?@action=redirect&bpo=18159].)

contextlib

새로운 redirect_stderr() 컨텍스트 관리자(redirect_stdout()과 유사)를 사용하면 유틸리티 스크립트가 출력을 sys.stderr에 기록하고 리디렉션 옵션을 제공하지 않는 유연하지 않은 API를 더 쉽게 처리할 수 있습니다:

>>> import contextlib, io, logging
>>> f = io.StringIO()
>>> with contextlib.redirect_stderr(f):
...     logging.warning('warning')
...
>>> f.getvalue()
'WARNING:root:warning\n'

(Contributed by Berker Peksag in bpo-22389 [https://bugs.python.org/issue?@action=redirect&bpo=22389].)

csv

writerow() 메서드는 이제 시퀀스뿐만 아니라 임의의 이터러블을 지원합니다. (Contributed by Serhiy Storchaka in bpo-23171 [https://bugs.python.org/issue?@action=redirect&bpo=23171].)

curses

The new update_lines_cols() function updates the LINES and COLS module variables. This is useful for detecting manual screen resizing. (Contributed by Arnon Yaari in bpo-4254 [https://bugs.python.org/issue?@action=redirect&bpo=4254].)

dbm

dumb.open은 플래그 값이 "n"일 때 항상 새 데이터베이스를 만듭니다. (Contributed by Claudiu Popa in bpo-18039 [https://bugs.python.org/issue?@action=redirect&bpo=18039].)

difflib

HtmlDiff.make_file()에 의해 생성된 HTML 문서의 문자 집합은 이제 새로운 charset 키워드 전용 인자를 사용하여 사용자 정의 할 수 있습니다. HTML 문서의 기본 문자 집합이 "ISO-8859-1"에서 "utf-8"로 변경되었습니다. (Contributed by Berker Peksag in bpo-2052 [https://bugs.python.org/issue?@action=redirect&bpo=2052].)

diff_bytes() 함수는 이제 바이트 문자열 리스트를 비교할 수 있습니다. 이것은 파이썬 2의 회귀를 수리합니다. (Contributed by Terry J. Reedy and Greg Ward in bpo-17445 [https://bugs.python.org/issue?@action=redirect&bpo=17445].)

distutils

build와 build_ext 명령은 이제 -j 옵션을 받아들여 확장 모듈의 병렬 빌드를 활성화합니다. (Contributed by Antoine Pitrou in bpo-5309 [https://bugs.python.org/issue?@action=redirect&bpo=5309].)

The distutils module now supports xz compression, and can be enabled by passing xztar as an argument to bdist --format. (Contributed by Serhiy Storchaka in bpo-16314 [https://bugs.python.org/issue?@action=redirect&bpo=16314].)

doctest

DocTestSuite() 함수는 module에 독스트링이 없으면 ValueError를 발생시키는 대신 빈 unittest.TestSuite를 반환합니다. (Contributed by Glenn Jones in bpo-15916 [https://bugs.python.org/issue?@action=redirect&bpo=15916].)

email

새로운 정책 옵션 Policy.mangle_from_은 생성자가 이메일 본문에서 "From "으로 시작하는 줄에 ">" 문자를 접두사로 추가할지를 제어합니다. 기본값은 compat32의 경우 True이고 다른 모든 정책의 경우 False입니다. (Contributed by Milan Oberkirch in bpo-20098 [https://bugs.python.org/issue?@action=redirect&bpo=20098].)

새로운 Message.get_content_disposition() 메서드를 사용하면 Content-Disposition 헤더의 규범적 값에 쉽게 액세스 할 수 있습니다. (Contributed by Abhilash Raj in bpo-21083 [https://bugs.python.org/issue?@action=redirect&bpo=21083].)

새로운 정책 옵션 EmailPolicy.utf8을 True로 설정하여 인코딩된 단어를 사용하는 대신 UTF-8 문자 집합을 사용하여 이메일 헤더를 인코딩 할 수 있습니다. 이를 통해 Messages를 RFC 6532 [https://datatracker.ietf.org/doc/html/rfc6532.html]에 따라 포매팅하고 RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html] SMTPUTF8 확장을 지원하는 SMTP 서버와 함께 사용할 수 있습니다. (Contributed by R. David Murray in bpo-24211 [https://bugs.python.org/issue?@action=redirect&bpo=24211].)

mime.text.MIMEText 생성자는 이제 charset.Charset 인스턴스를 받아들입니다. (Contributed by Claude Paroz and Berker Peksag in bpo-16324 [https://bugs.python.org/issue?@action=redirect&bpo=16324].)

enum

Enum 콜러블에는 names만 제공되는 경우 열거형 값의 초기 수를 지정하는 새 매개 변수 start가 있습니다:

>>> Animal = enum.Enum('Animal', 'cat dog', start=10)
>>> Animal.cat
<Animal.cat: 10>
>>> Animal.dog
<Animal.dog: 11>

(Contributed by Ethan Furman in bpo-21706 [https://bugs.python.org/issue?@action=redirect&bpo=21706].)

faulthandler

enable(), register(), dump_traceback() 및 dump_traceback_later() 함수는 이제 파일류 객체 외에도 파일 기술자를 받아들입니다. (Contributed by Wei Wu in bpo-23566 [https://bugs.python.org/issue?@action=redirect&bpo=23566].)

functools

대부분의 lru_cache() 장치는 이제 C로 구현되어 훨씬 빨라졌습니다. (Contributed by Matt Joiner, Alexey Kachayev, and Serhiy Storchaka in bpo-14373 [https://bugs.python.org/issue?@action=redirect&bpo=14373].)

glob

iglob()과 glob() 함수는 이제 "**" 패턴을 사용하여 하위 디렉터리에서 재귀 검색을 지원합니다. (Contributed by Serhiy Storchaka in bpo-13968 [https://bugs.python.org/issue?@action=redirect&bpo=13968].)

gzip

GzipFile 생성자의 mode 인자는 이제 배타적 생성을 요청하는 "x"를 받아들입니다. (Contributed by Tim Heaney in bpo-19222 [https://bugs.python.org/issue?@action=redirect&bpo=19222].)

heapq

merge()의 요소 비교는 이제 새로운 선택적 key 키워드 인자에 키 함수를 전달하여 사용자 정의 할 수 있으며, 새로운 선택적 reverse 키워드 인자를 사용하여 요소 비교를 반전할 수 있습니다:

>>> import heapq
>>> a = ['9', '777', '55555']
>>> b = ['88', '6666']
>>> list(heapq.merge(a, b, key=len))
['9', '88', '777', '6666', '55555']
>>> list(heapq.merge(reversed(a), reversed(b), key=len, reverse=True))
['55555', '6666', '777', '88', '9']

(Contributed by Raymond Hettinger in bpo-13742 [https://bugs.python.org/issue?@action=redirect&bpo=13742].)

http

HTTP 상태 코드, 이유 구문 및 영어로 작성된 자세한 설명의 집합을 정의하는 새로운 HTTPStatus 열거형. (Contributed by Demian Brecht in bpo-21793 [https://bugs.python.org/issue?@action=redirect&bpo=21793].)

http.client

HTTPConnection.getresponse()는 이제 원격 서버 연결이 예기치 않게 닫힐 때 RemoteDisconnected 예외를 발생시킵니다. 또한 ConnectionError(RemoteDisconnected는 이것의 서브 클래스입니다)가 발생하면, 클라이언트 소켓이 이제 자동으로 닫히고 다음 요청에 다시 연결됩니다:

import http.client
conn = http.client.HTTPConnection('www.python.org')
for retries in range(3):
    try:
        conn.request('GET', '/')
        resp = conn.getresponse()
    except http.client.RemoteDisconnected:
        pass

(Contributed by Martin Panter in bpo-3566 [https://bugs.python.org/issue?@action=redirect&bpo=3566].)

idlelib 및 IDLE

idlelib는 IDLE 셸과 편집기를 구현하고 다른 프로그램에서 임포트 하려는 것이 아니기 때문에, 모든 릴리스에서 개선됩니다. 3.4.0 이후의 누적 변경 사항과 향후 3.5.x 릴리스에서 변경된 사항은 Lib/idlelib/NEWS.txt를 참조하십시오. 이 파일은 IDLE Help ‣ About IDLE 대화 상자에서도 제공됩니다.

imaplib

IMAP4 클래스는 이제 컨텍스트 관리자 프로토콜을 지원합니다. with 문에서 사용하면 IMAP4 LOGOUT 명령이 블록 끝에서 자동으로 호출됩니다. (Contributed by Tarek Ziadé and Serhiy Storchaka in bpo-4972 [https://bugs.python.org/issue?@action=redirect&bpo=4972].)

imaplib 모듈은 이제 IMAP4.enable() 메서드를 통해 RFC 5161 [https://datatracker.ietf.org/doc/html/rfc5161.html](ENABLE 확장) 및 RFC 6855 [https://datatracker.ietf.org/doc/html/rfc6855.html](UTF-8 지원)를 지원합니다. 새로운 IMAP4.utf8_enabled 어트리뷰트는 RFC 6855 [https://datatracker.ietf.org/doc/html/rfc6855.html] 지원이 활성화되었는지를 추적합니다. (Contributed by Milan Oberkirch, R. David Murray, and Maciej Szulik in bpo-21800 [https://bugs.python.org/issue?@action=redirect&bpo=21800].)

이제 imaplib 모듈은 이제 RFC에서 권장하는 대로 UTF-8을 사용하여 ASCII가 아닌 문자열 사용자 이름과 암호를 자동으로 인코딩합니다. (Contributed by Milan Oberkirch in bpo-21800 [https://bugs.python.org/issue?@action=redirect&bpo=21800].)

imghdr

The what() function now recognizes the OpenEXR [https://www.openexr.com] format (contributed by Martin Vignali and Claudiu Popa in bpo-20295 [https://bugs.python.org/issue?@action=redirect&bpo=20295]), and the WebP [https://en.wikipedia.org/wiki/WebP] format (contributed by Fabrice Aneche and Claudiu Popa in bpo-20197 [https://bugs.python.org/issue?@action=redirect&bpo=20197].)

importlib

util.LazyLoader 클래스는 시작 소요 시간이 중요한 응용 프로그램에서 모듈의 지연 로드를 허용합니다. (Contributed by Brett Cannon in bpo-17621 [https://bugs.python.org/issue?@action=redirect&bpo=17621].)

abc.InspectLoader.source_to_code() 메서드는 이제 정적 메서드입니다. 이렇게 하면 exec(code, module.__dict__)를 실행하여 문자열에서 컴파일된 코드로 모듈 객체를 더 쉽게 초기화 할 수 있습니다. (Contributed by Brett Cannon in bpo-21156 [https://bugs.python.org/issue?@action=redirect&bpo=21156].)

새 util.module_from_spec() 함수는 이제 새 모듈을 만드는 데 선호되는 방법입니다. types.ModuleType 인스턴스를 직접 만드는 것과는 반대로, 이 새로운 함수는 전달된 명세 객체를 기반으로 다양한 임포트 제어 어트리뷰트를 설정합니다. (Contributed by Brett Cannon in bpo-20383 [https://bugs.python.org/issue?@action=redirect&bpo=20383].)

inspect

Signature와 Parameter 클래스 모두 이제 피클 가능하고 해시 가능합니다. (Contributed by Yury Selivanov in bpo-20726 [https://bugs.python.org/issue?@action=redirect&bpo=20726] and bpo-20334 [https://bugs.python.org/issue?@action=redirect&bpo=20334].)

새로운 BoundArguments.apply_defaults() 메서드는 누락 된 인자에 대한 기본값을 설정하는 방법을 제공합니다:

>>> def foo(a, b='ham', *args): pass
>>> ba = inspect.signature(foo).bind('spam')
>>> ba.apply_defaults()
>>> ba.arguments
OrderedDict([('a', 'spam'), ('b', 'ham'), ('args', ())])

(Contributed by Yury Selivanov in bpo-24190 [https://bugs.python.org/issue?@action=redirect&bpo=24190].)

새로운 클래스 메서드 Signature.from_callable()은 Signature의 서브 클래싱을 더 쉽게 만듭니다. (Contributed by Yury Selivanov and Eric Snow in bpo-17373 [https://bugs.python.org/issue?@action=redirect&bpo=17373].)

signature() 함수는 이제 follow_wrapped 선택적 키워드 인자를 받아들이며, False로 설정되면 __wrapped__ 링크의 자동 추적을 비활성화합니다. (Contributed by Yury Selivanov in bpo-20691 [https://bugs.python.org/issue?@action=redirect&bpo=20691].)

코루틴 함수와 코루틴 객체를 검사하는 새로운 함수 집합 : iscoroutine(), iscoroutinefunction(), isawaitable(), getcoroutinelocals() 및 getcoroutinestate() 가 추가되었습니다. (Contributed by Yury Selivanov in bpo-24017 [https://bugs.python.org/issue?@action=redirect&bpo=24017] and bpo-24400 [https://bugs.python.org/issue?@action=redirect&bpo=24400].)

stack(), trace(), getouterframes() 및 getinnerframes() 함수는 이제 네임드 튜플 리스트를 반환합니다. (Contributed by Daniel Shahaf in bpo-16808 [https://bugs.python.org/issue?@action=redirect&bpo=16808].)

io

하부 원시 스트림의 RawIOBase.read()나 RawIOBase.readinto() 메서드에 대한 호출을 최대 한 번 사용하는 새로운 BufferedIOBase.readinto1() 메서드. (Contributed by Nikolaus Rath in bpo-20578 [https://bugs.python.org/issue?@action=redirect&bpo=20578].)

ipaddress

IPv4Network와 IPv6Network 클래스는 이제 기존 주소에서 네트워크 객체를 쉽게 구성할 수 있도록 (address, netmask) 튜플 인자를 받아들입니다:

>>> import ipaddress
>>> ipaddress.IPv4Network(('127.0.0.0', 8))
IPv4Network('127.0.0.0/8')
>>> ipaddress.IPv4Network(('127.0.0.0', '255.0.0.0'))
IPv4Network('127.0.0.0/8')

(Contributed by Peter Moody and Antoine Pitrou in bpo-16531 [https://bugs.python.org/issue?@action=redirect&bpo=16531].)

IPv4Network와 IPv6Network 클래스의 새로운 reverse_pointer 어트리뷰트는 역 DNS PTR 레코드의 이름을 반환합니다:

>>> import ipaddress
>>> addr = ipaddress.IPv4Address('127.0.0.1')
>>> addr.reverse_pointer
'1.0.0.127.in-addr.arpa'
>>> addr6 = ipaddress.IPv6Address('::1')
>>> addr6.reverse_pointer
'1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa'

(Contributed by Leon Weber in bpo-20480 [https://bugs.python.org/issue?@action=redirect&bpo=20480].)

json

json.tool 명령 줄 인터페이스는 이제 입력으로 전달된 JSON 객체의 키 순서를 유지합니다. 새로운 --sort-keys 옵션을 사용하여 키를 알파벳순으로 정렬 할 수 있습니다. (Contributed by Berker Peksag in bpo-21650 [https://bugs.python.org/issue?@action=redirect&bpo=21650].)

이제 JSON 디코더는 에러에 대한 더 나은 문맥 정보를 제공하기 위해 ValueError 대신 JSONDecodeError를 발생시킵니다. (Contributed by Serhiy Storchaka in bpo-19361 [https://bugs.python.org/issue?@action=redirect&bpo=19361].)

linecache

새로운 lazycache() 함수를 사용하여 파일 기반이 아닌 모듈에 대한 정보를 캡처하여 나중에 getline()을 통해 해당 라인을 가져올 수 있습니다. 이렇게 하면 모듈 전역을 무기한으로 유지할 필요 없이, 실제로 줄이 필요할 때까지 I/O를 수행하지 않습니다. (Contributed by Robert Collins in bpo-17911 [https://bugs.python.org/issue?@action=redirect&bpo=17911].)

locale

새로운 delocalize() 함수를 사용하여 LC_NUMERIC 설정을 고려하여 문자열을 정규화된 숫자 문자열로 변환 할 수 있습니다:

>>> import locale
>>> locale.setlocale(locale.LC_NUMERIC, 'de_DE.UTF-8')
'de_DE.UTF-8'
>>> locale.delocalize('1.234,56')
'1234.56'
>>> locale.setlocale(locale.LC_NUMERIC, 'en_US.UTF-8')
'en_US.UTF-8'
>>> locale.delocalize('1,234.56')
'1234.56'

(Contributed by Cédric Krier in bpo-13918 [https://bugs.python.org/issue?@action=redirect&bpo=13918].)

logging

모든 로깅 메서드(Logger log(), exception(), critical(), debug() 등)는 이제 불리언 값과 예외 튜플 외에도 예외 인스턴스를 exc_info 인자로 받아들입니다:

>>> import logging
>>> try:
...     1/0
... except ZeroDivisionError as ex:
...     logging.error('exception', exc_info=ex)
ERROR:root:exception

(Contributed by Yury Selivanov in bpo-20537 [https://bugs.python.org/issue?@action=redirect&bpo=20537].)

이제 handlers.HTTPHandler 클래스는 HTTP 연결에 사용되는 SSL 설정을 구성하기 위해 선택적 ssl.SSLContext 인스턴스를 받아들입니다. (Contributed by Alex Gaynor in bpo-22788 [https://bugs.python.org/issue?@action=redirect&bpo=22788].)

handlers.QueueListener 클래스는 이제 respect_handler_level 키워드 인자를 취합니다. 이 인자는 True로 설정되면 처리기 수준을 고려하여 처리기에 메시지를 전달합니다. (Contributed by Vinay Sajip.)

lzma

이제 LZMADecompressor.decompress() 메서드는 압축 해제된 데이터의 최대 크기를 제한하기 위해 선택적 max_length 인자를 받아들입니다. (Contributed by Martin Panter in bpo-15955 [https://bugs.python.org/issue?@action=redirect&bpo=15955].)

math

math 모듈에 inf와 nan의 두 가지 새로운 상수가 추가되었습니다. (Contributed by Mark Dickinson in bpo-23185 [https://bugs.python.org/issue?@action=redirect&bpo=23185].)

새로운 함수 isclose()는 대략적인 동등성을 테스트하는 방법을 제공합니다. (Contributed by Chris Barker and Tal Einat in bpo-24270 [https://bugs.python.org/issue?@action=redirect&bpo=24270].)

새로운 gcd() 함수가 추가되었습니다. fractions.gcd() 함수는 이제 폐지되었습니다. (Contributed by Mark Dickinson and Serhiy Storchaka in bpo-22486 [https://bugs.python.org/issue?@action=redirect&bpo=22486].)

multiprocessing

sharedctypes.synchronized() 객체는 이제 컨텍스트 관리자 프로토콜을 지원합니다. (Contributed by Charles-François Natali in bpo-21565 [https://bugs.python.org/issue?@action=redirect&bpo=21565].)

operator

attrgetter(), itemgetter() 및 methodcaller() 객체는 이제 피클링을 지원합니다. (Contributed by Josh Rosenberg and Serhiy Storchaka in bpo-22955 [https://bugs.python.org/issue?@action=redirect&bpo=22955].)

행렬 곱셈을 수행하는 새로운 matmul()과 imatmul() 함수. (Contributed by Benjamin Peterson in bpo-21176 [https://bugs.python.org/issue?@action=redirect&bpo=21176].)

os

DirEntry 객체의 이터레이터를 반환하는 새로운 scandir() 함수가 추가되었습니다. 가능하면, scandir()은 디렉터리를 스캔하는 동안 파일 어트리뷰트를 추출하여, 파일 유형이나 어트리뷰트를 파악하기 위해 후속 시스템 호출을 수행할 필요가 없어서, 성능이 크게 향상될 수 있습니다. (Contributed by Ben Hoyt with the help of Victor Stinner in bpo-22524 [https://bugs.python.org/issue?@action=redirect&bpo=22524].)

윈도우에서, 이제 새로운 stat_result.st_file_attributes 어트리뷰트를 사용할 수 있습니다. GetFileInformationByHandle() 이 반환한 BY_HANDLE_FILE_INFORMATION 구조체의 dwFileAttributes 멤버에 해당합니다. (Contributed by Ben Hoyt in bpo-21719 [https://bugs.python.org/issue?@action=redirect&bpo=21719].)

urandom() 함수는 이제 리눅스 3.17 이상에서 getrandom() 시스템 호출을 사용하고, OpenBSD 5.6 이상에서 getentropy()를 사용하여, /dev/urandom을 사용할 필요가 없고 잠재적인 파일 기술자 고갈로 인한 실패를 방지합니다. (Contributed by Victor Stinner in bpo-22181 [https://bugs.python.org/issue?@action=redirect&bpo=22181].)

New get_blocking() and set_blocking() functions allow getting and setting a file descriptor’s blocking mode (O_NONBLOCK.) (Contributed by Victor Stinner in bpo-22054 [https://bugs.python.org/issue?@action=redirect&bpo=22054].)

이제 truncate()와 ftruncate() 함수가 이제 윈도우에서 지원됩니다. (Contributed by Steve Dower in bpo-23668 [https://bugs.python.org/issue?@action=redirect&bpo=23668].)

전달된 각 경로명의 가장 긴 공통 하위 경로를 반환하는 새로운 os.path.commonpath() 함수가 있습니다. os.path.commonprefix() 함수와 달리, 항상 유효한 경로를 반환합니다:

>>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])
'/usr/l'

>>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])
'/usr'

(Contributed by Rafik Draoui and Serhiy Storchaka in bpo-10395 [https://bugs.python.org/issue?@action=redirect&bpo=10395].)

pathlib

새로운 Path.samefile() 메서드를 사용하여 다른 Path 객체나 문자열일 수 있는 다른 경로와 같은 파일을 가리키는지를 확인할 수 있습니다:

>>> import pathlib
>>> p1 = pathlib.Path('/etc/hosts')
>>> p2 = pathlib.Path('/etc/../etc/hosts')
>>> p1.samefile(p2)
True

(Contributed by Vajrasky Kok and Antoine Pitrou in bpo-19775 [https://bugs.python.org/issue?@action=redirect&bpo=19775].)

Path.mkdir() 메서드는 이제 mkdir -p와 os.makedirs() 기능과 일치하는 새로운 선택적 exist_ok 인자를 받아들입니다. (Contributed by Berker Peksag in bpo-21539 [https://bugs.python.org/issue?@action=redirect&bpo=21539].)

~와 ~user 접두사를 확장하는 새로운 Path.expanduser() 메서드가 있습니다. (Contributed by Serhiy Storchaka and Claudiu Popa in bpo-19776 [https://bugs.python.org/issue?@action=redirect&bpo=19776].)

새로운 Path.home() 클래스 메서드를 사용하여 사용자의 홈 디렉터리를 나타내는 Path 인스턴스를 가져올 수 있습니다. (Contributed by Victor Salgado and Mayank Tripathi in bpo-19777 [https://bugs.python.org/issue?@action=redirect&bpo=19777].)

파일에 대한 읽기/쓰기 연산을 단순화하는 새로운 Path.write_text(), Path.read_text(), Path.write_bytes(), Path.read_bytes() 메서드.

다음 코드 조각은 ~/spam42를 만들거나 기존 파일을 다시 작성합니다:

>>> import pathlib
>>> p = pathlib.Path('~/spam42')
>>> p.expanduser().write_text('ham')
3

(Contributed by Christopher Welborn in bpo-20218 [https://bugs.python.org/issue?@action=redirect&bpo=20218].)

pickle

연결되지 않은 메서드나 중첩된 클래스와 같은 중첩 된 객체는 이제 프로토콜 버전 4보다 오래된 피클 프로토콜을 사용하여 피클 할 수 있습니다. 프로토콜 버전 4는 이미 이러한 경우를 지원합니다. (Contributed by Serhiy Storchaka in bpo-23611 [https://bugs.python.org/issue?@action=redirect&bpo=23611].)

poplib

새로운 POP3.utf8() 명령은 POP 서버가 지원하면 RFC 6856 [https://datatracker.ietf.org/doc/html/rfc6856.html] (국제화된 이메일) 지원을 활성화합니다. (Contributed by Milan OberKirch in bpo-21804 [https://bugs.python.org/issue?@action=redirect&bpo=21804].)

re

고정 길이를 가진 그룹에 대한 참조와 조건부 참조는 이제 되돌아보기 어서션(lookbehind assertions)에서 허용됩니다:

>>> import re
>>> pat = re.compile(r'(a|b).(?<=\1)c')
>>> pat.match('aac')
<_sre.SRE_Match object; span=(0, 3), match='aac'>
>>> pat.match('bbc')
<_sre.SRE_Match object; span=(0, 3), match='bbc'>

(Contributed by Serhiy Storchaka in bpo-9179 [https://bugs.python.org/issue?@action=redirect&bpo=9179].)

정규식의 캡처 그룹 수는 더는 100개로 제한되지 않습니다. (Contributed by Serhiy Storchaka in bpo-22437 [https://bugs.python.org/issue?@action=redirect&bpo=22437].)

sub()와 subn() 함수는 이제 예외를 발생시키는 대신 일치하지 않는 그룹을 빈 문자열로 대체합니다. (Contributed by Serhiy Storchaka in bpo-1519638 [https://bugs.python.org/issue?@action=redirect&bpo=1519638].)

re.error 예외에는 에러에 대한 더 나은 문맥 정보를 제공하는 새 어트리뷰트인 msg, pattern, pos, lineno 및 colno가 있습니다:

>>> re.compile("""
...     (?x)
...     .++
... """)
Traceback (most recent call last):
   ...
sre_constants.error: multiple repeat at position 16 (line 3, column 7)

(Contributed by Serhiy Storchaka in bpo-22578 [https://bugs.python.org/issue?@action=redirect&bpo=22578].)

readline

새로운 append_history_file() 함수를 사용하여 지정된 파일에 히스토리에 지정된 수의 후행 요소를 추가 할 수 있습니다. (Contributed by Bruno Cauet in bpo-22940 [https://bugs.python.org/issue?@action=redirect&bpo=22940].)

selectors

새로운 DevpollSelector는 Solaris에서 효율적인 /dev/poll 폴링을 지원합니다. (Contributed by Giampaolo Rodola’ in bpo-18931 [https://bugs.python.org/issue?@action=redirect&bpo=18931].)

Shutil

move() 함수는 이제 copy_function 인자를 받아들여, 예를 들어, 이동할 때 파일 메타 데이터를 무시해야 하면 기본 copy2() 대신 copy() 함수를 사용할 수 있습니다. (Contributed by Claudiu Popa in bpo-19840 [https://bugs.python.org/issue?@action=redirect&bpo=19840].)

make_archive() 함수는 이제 xztar 형식을 지원합니다. (Contributed by Serhiy Storchaka in bpo-5411 [https://bugs.python.org/issue?@action=redirect&bpo=5411].)

signal

윈도우에서, set_wakeup_fd() 함수는 이제 소켓 핸들도 지원합니다. (Contributed by Victor Stinner in bpo-22018 [https://bugs.python.org/issue?@action=redirect&bpo=22018].)

signal 모듈의 다양한 SIG* 상수가 열거형으로 변환되었습니다. 이를 통해 디버깅 중에 정수 “매직 넘버” 대신 의미 있는 이름을 인쇄할 수 있습니다. (Contributed by Giampaolo Rodola’ in bpo-21076 [https://bugs.python.org/issue?@action=redirect&bpo=21076].)

smtpd

Both the SMTPServer and SMTPChannel classes now accept a decode_data keyword argument to determine if the DATA portion of the SMTP transaction is decoded using the "utf-8" codec or is instead provided to the SMTPServer.process_message() method as a byte string. The default is True for backward compatibility reasons, but will change to False in Python 3.6. If decode_data is set to False, the process_message method must be prepared to accept keyword arguments. (Contributed by Maciej Szulik in bpo-19662 [https://bugs.python.org/issue?@action=redirect&bpo=19662].)

The SMTPServer class now advertises the 8BITMIME extension (RFC 6152 [https://datatracker.ietf.org/doc/html/rfc6152.html]) if decode_data has been set True. If the client specifies BODY=8BITMIME on the MAIL command, it is passed to SMTPServer.process_message() via the mail_options keyword. (Contributed by Milan Oberkirch and R. David Murray in bpo-21795 [https://bugs.python.org/issue?@action=redirect&bpo=21795].)

The SMTPServer class now also supports the SMTPUTF8 extension (RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html]: Internationalized Email). If the client specified SMTPUTF8 BODY=8BITMIME on the MAIL command, they are passed to SMTPServer.process_message() via the mail_options keyword. It is the responsibility of the process_message method to correctly handle the SMTPUTF8 data. (Contributed by Milan Oberkirch in bpo-21725 [https://bugs.python.org/issue?@action=redirect&bpo=21725].)

It is now possible to provide, directly or via name resolution, IPv6 addresses in the SMTPServer constructor, and have it successfully connect. (Contributed by Milan Oberkirch in bpo-14758 [https://bugs.python.org/issue?@action=redirect&bpo=14758].)

smtplib

새로운 SMTP.auth() 메서드는 사용자 정의 인증 메커니즘을 구현하는 편리한 방법을 제공합니다. (Contributed by Milan Oberkirch in bpo-15014 [https://bugs.python.org/issue?@action=redirect&bpo=15014].)

SMTP.set_debuglevel() 메서드는 이제 디버그 메시지에서 타임 스탬프를 활성화하는 추가 디버그 수준(2)을 받아들입니다. (Contributed by Gavin Chappell and Maciej Szulik in bpo-16914 [https://bugs.python.org/issue?@action=redirect&bpo=16914].)

SMTP.sendmail()과 SMTP.send_message() 메서드 모두 이제 RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html](SMTPUTF8)을 지원합니다. (Contributed by Milan Oberkirch and R. David Murray in bpo-22027 [https://bugs.python.org/issue?@action=redirect&bpo=22027].)

sndhdr

The what() and whathdr() functions now return a namedtuple(). (Contributed by Claudiu Popa in bpo-18615 [https://bugs.python.org/issue?@action=redirect&bpo=18615].)

socket

제한 시간이 있는 함수는 이제 시스템 시계 대신 단조증가(monotonic) 시계를 사용합니다. (Contributed by Victor Stinner in bpo-22043 [https://bugs.python.org/issue?@action=redirect&bpo=22043].)

새로운 socket.sendfile() 메서드를 사용하면 유닉스에서 고성능 os.sendfile() 함수를 사용하여 소켓을 통해 파일을 전송할 수 있어서, 일반 socket.send()를 사용할 때 보다 업로드 속도가 2 에서 3배 빨라집니다. (Contributed by Giampaolo Rodola’ in bpo-17552 [https://bugs.python.org/issue?@action=redirect&bpo=17552].)

socket.sendall() 메서드는 더는 바이트를 받거나 보낼 때마다 소켓 시간제한을 재설정하지 않습니다. 소켓 시간제한은 이제 모든 데이터를 보내는 최대 총 기간입니다. (Contributed by Victor Stinner in bpo-23853 [https://bugs.python.org/issue?@action=redirect&bpo=23853].)

socket.listen() 메서드의 backlog 인자는 이제 선택 사항입니다. 기본적으로 SOMAXCONN나 128중 작은 값으로 설정됩니다. (Contributed by Charles-François Natali in bpo-21455 [https://bugs.python.org/issue?@action=redirect&bpo=21455].)

ssl

메모리 BIO 지원

(Contributed by Geert Jansen in bpo-21965 [https://bugs.python.org/issue?@action=redirect&bpo=21965].)

새로운 SSLObject 클래스가 추가되어 SSLSocket의 네트워크 I/O 기능이 필요하지 않거나 최적이 아닐 때 SSL 프로토콜 지원을 제공합니다. SSLObject는 SSL 프로토콜 인스턴스를 나타내지만, 네트워크 I/O 메서드를 구현하지 않고 대신 메모리 버퍼 인터페이스를 제공합니다. 새로운 MemoryBIO 클래스는 파이썬과 SSL 프로토콜 인스턴스 간에 데이터를 전달하는 데 사용할 수 있습니다.

메모리 BIO SSL 지원은 주로 SSLSocket의 준비(readiness) 모델 (“select/poll”)이 비효율적인 비동기 I/O를 구현하는 프레임워크에서 사용하기 위한 것입니다.

새 SSLContext.wrap_bio() 메서드를 사용하여 새 SSLObject 인스턴스를 만들 수 있습니다.

응용 프로그램 계층 프로토콜 협상 지원

(Contributed by Benjamin Peterson in bpo-20188 [https://bugs.python.org/issue?@action=redirect&bpo=20188].)

OpenSSL 지원이 있는 경우, ssl 모듈은 이제 RFC 7301 [https://datatracker.ietf.org/doc/html/rfc7301.html]에 설명된 대로 응용 프로그램 계층 프로토콜 협상(Application-Layer Protocol Negotiation) TLS 확장을 구현합니다.

새로운 SSLContext.set_alpn_protocols()는 소켓이 TLS 핸드 셰이크 중에 어떤 프로토콜을 알려야 하는지 지정하는 데 사용할 수 있습니다.

The new SSLSocket.selected_alpn_protocol() returns the protocol that was selected during the TLS handshake. The HAS_ALPN flag indicates whether ALPN support is present.

기타 변경 사항

사용 중인 실제 프로토콜 버전을 조회하는 새로운 SSLSocket.version() 메서드가 있습니다. (Contributed by Antoine Pitrou in bpo-20421 [https://bugs.python.org/issue?@action=redirect&bpo=20421].)

SSLSocket 클래스는 이제 SSLSocket.sendfile() 메서드를 구현합니다. (Contributed by Giampaolo Rodola’ in bpo-17552 [https://bugs.python.org/issue?@action=redirect&bpo=17552].)

SSLSocket.send() 메서드는 이제 연산이 블록 되려고 하면 비 블로킹 소켓에서 ssl.SSLWantReadError 나 ssl.SSLWantWriteError 예외를 발생시킵니다. 이전에는 0을 반환했습니다. (Contributed by Nikolaus Rath in bpo-20951 [https://bugs.python.org/issue?@action=redirect&bpo=20951].)

cert_time_to_seconds() 함수는 이제 입력 시간을 RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html]에 따라 현지 시간이 아닌 UTC로 해석합니다. 또한, 반환 값은 항상 int입니다. (Contributed by Akira Li in bpo-19940 [https://bugs.python.org/issue?@action=redirect&bpo=19940].)

새로운 SSLObject.shared_ciphers()와 SSLSocket.shared_ciphers() 메서드는 핸드 셰이크 중에 클라이언트가 보낸 사이퍼 리스트를 반환합니다. (Contributed by Benjamin Peterson in bpo-23186 [https://bugs.python.org/issue?@action=redirect&bpo=23186].)

SSLSocket 클래스의 SSLSocket.do_handshake(), SSLSocket.read(), SSLSocket.shutdown() 및 SSLSocket.write() 메서드는 더는 바이트를 받거나 보낼 때마다 소켓 시간제한을 재설정하지 않습니다. 소켓 시간제한은 이제 메서드의 최대 총 지속 시간입니다. (Contributed by Victor Stinner in bpo-23853 [https://bugs.python.org/issue?@action=redirect&bpo=23853].)

match_hostname() 함수는 이제 IP 주소 일치를 지원합니다. (Contributed by Antoine Pitrou in bpo-23239 [https://bugs.python.org/issue?@action=redirect&bpo=23239].)

sqlite3

Row 클래스는 이제 시퀀스 프로토콜, 특히 reversed() 이터레이션과 슬라이스 인덱싱을 완전히 지원합니다. (Contributed by Claudiu Popa in bpo-10203 [https://bugs.python.org/issue?@action=redirect&bpo=10203]; by Lucas Sinclair, Jessica McKellar, and Serhiy Storchaka in bpo-13583 [https://bugs.python.org/issue?@action=redirect&bpo=13583].)

subprocess

새로운 run() 함수가 추가되었습니다. 지정된 명령을 실행하고 완료된 프로세스를 설명하는 CompletedProcess 객체를 반환합니다. 새 API는 더 일관적이며 이전 파이썬 버전과의 호환성을 유지할 필요가 없는 파이썬 코드에서 서브 프로세스를 호출하는 데 권장되는 접근 방식입니다. (Contributed by Thomas Kluyver in bpo-23342 [https://bugs.python.org/issue?@action=redirect&bpo=23342].)

예:

>>> subprocess.run(["ls", "-l"])  # doesn't capture output
CompletedProcess(args=['ls', '-l'], returncode=0)

>>> subprocess.run("exit 1", shell=True, check=True)
Traceback (most recent call last):
  ...
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

>>> subprocess.run(["ls", "-l", "/dev/null"], stdout=subprocess.PIPE)
CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n')

sys

새로운 set_coroutine_wrapper() 함수를 사용하면 async def 함수에 의해 코루틴 객체가 만들어질 때마다 호출되는 전역 훅을 설정할 수 있습니다. 해당 get_coroutine_wrapper()를 사용하여 현재 설정된 래퍼를 얻을 수 있습니다. 두 함수 모두 잠정적이며 디버깅 목적으로만 사용됩니다. (Contributed by Yury Selivanov in bpo-24017 [https://bugs.python.org/issue?@action=redirect&bpo=24017].)

새로운 is_finalizing() 함수를 사용하여 파이썬 인터프리터가 종료 중인지 확인할 수 있습니다. (Contributed by Antoine Pitrou in bpo-22696 [https://bugs.python.org/issue?@action=redirect&bpo=22696].)

sysconfig

이제 윈도우의 사용자 스크립트 디렉터리 이름에 파이썬 버전의 처음 두 구성 요소가 포함됩니다. (Contributed by Paul Moore in bpo-23437 [https://bugs.python.org/issue?@action=redirect&bpo=23437].)

tarfile

open() 함수의 mode 인자는 이제 배타적 생성을 요청하는 "x"를 받아들입니다. (Contributed by Berker Peksag in bpo-21717 [https://bugs.python.org/issue?@action=redirect&bpo=21717].)

TarFile.extractall()과 TarFile.extract() 메서드는 이제 키워드 인자 numeric_owner를 취합니다. True로 설정하면, 압축을 푼 파일과 디렉터리는 tar 파일의 숫자 uid와 gid가 소유합니다. False(기본값, 또한 3.5 이전 버전의 동작)로 설정하면, tar 파일의 명명된 사용자와 그룹이 소유합니다. (Contributed by Michael Vogt and Eric Smith in bpo-23193 [https://bugs.python.org/issue?@action=redirect&bpo=23193].)

TarFile.list()는 이제 TarFile.getmembers()가 반환하는 리스트의 부분 집합으로 설정할 수 있는 선택적 members 키워드 인자를 받아들입니다. (Contributed by Serhiy Storchaka in bpo-21549 [https://bugs.python.org/issue?@action=redirect&bpo=21549].)

threading

이제 Lock.acquire()와 RLock.acquire() 메서드 모두 시간제한 관리에 단조증가(monotonic) 시계를 사용합니다. (Contributed by Victor Stinner in bpo-22043 [https://bugs.python.org/issue?@action=redirect&bpo=22043].)

time

monotonic() 함수는 이제 항상 사용할 수 있습니다. (Contributed by Victor Stinner in bpo-22043 [https://bugs.python.org/issue?@action=redirect&bpo=22043].)

timeit

새로운 명령 줄 옵션 -u나 --unit=U 를 사용하여 타이머 출력의 시간 단위를 지정할 수 있습니다. 지원되는 옵션은 usec, msec 또는 sec입니다. (Contributed by Julian Gindi in bpo-18983 [https://bugs.python.org/issue?@action=redirect&bpo=18983].)

timeit() 함수에는 코드가 실행될 이름 공간을 지정하기 위한 새로운 globals 매개 변수가 있습니다. (Contributed by Ben Roberts in bpo-2527 [https://bugs.python.org/issue?@action=redirect&bpo=2527].)

tkinter

The tkinter._fix module used for setting up the Tcl/Tk environment on Windows has been replaced by a private function in the _tkinter module which makes no permanent changes to environment variables. (Contributed by Zachary Ware in bpo-20035 [https://bugs.python.org/issue?@action=redirect&bpo=20035].)

traceback

New walk_stack() and walk_tb() functions to conveniently traverse frame and traceback objects. (Contributed by Robert Collins in bpo-17911 [https://bugs.python.org/issue?@action=redirect&bpo=17911].)

새로운 경량 클래스: TracebackException, StackSummary 및 FrameSummary. (Contributed by Robert Collins in bpo-17911 [https://bugs.python.org/issue?@action=redirect&bpo=17911].)

print_tb()와 print_stack() 함수는 모두 이제 limit 인자에 대해 음수 값을 지원합니다. (Contributed by Dmitry Kazakov in bpo-22619 [https://bugs.python.org/issue?@action=redirect&bpo=22619].)

types

제너레이터와 제너레이터류 객체를 어웨이터블로 변환하는 새로운 coroutine() 함수. (Contributed by Yury Selivanov in bpo-24017 [https://bugs.python.org/issue?@action=redirect&bpo=24017].)

async def 함수로 만든 코루틴 객체에 사용되는 CoroutineType라는 새로운 형. (Contributed by Yury Selivanov in bpo-24400 [https://bugs.python.org/issue?@action=redirect&bpo=24400].)

unicodedata

The unicodedata module now uses data from Unicode 8.0.0 [https://unicode.org/versions/Unicode8.0.0/].

unittest

TestLoader.loadTestsFromModule() 메서드는 이제 load_tests에 세 번째 인자로 전달되는 키워드 전용 인자 pattern을 받아들입니다. 패키지 이름이 기본 패턴과 일치할 수 없어서, 이제 발견된 패키지의 경로가 pattern과 일치하는지와 관계없이 load_tests를 확인합니다. (Contributed by Robert Collins and Barry A. Warsaw in bpo-16662 [https://bugs.python.org/issue?@action=redirect&bpo=16662].)

이제 unittest 디스커버리 에러가 TestLoader 인스턴스의 TestLoader.errors 어트리뷰트에 표시됩니다. (Contributed by Robert Collins in bpo-19746 [https://bugs.python.org/issue?@action=redirect&bpo=19746].)

트레이스백에 지역 변수를 표시하는 새로운 명령 줄 옵션 --locals. (Contributed by Robert Collins in bpo-22936 [https://bugs.python.org/issue?@action=redirect&bpo=22936].)

unittest.mock

Mock 클래스는 다음과 같이 개선되었습니다:

클래스 생성자에는 "assert"로 시작하는 어트리뷰트 이름에 대해 모의 객체가 AttributeError를 발생시키는 새로운 unsafe 매개 변수가 있습니다. (Contributed by Kushal Das in bpo-21238 [https://bugs.python.org/issue?@action=redirect&bpo=21238].)

모의 객체가 호출되었는지 확인하는 새로운 Mock.assert_not_called() 메서드. (Contributed by Kushal Das in bpo-21262 [https://bugs.python.org/issue?@action=redirect&bpo=21262].)

MagicMock 클래스는 이제 __truediv__(), __divmod__() 및 __matmul__() 연산자를 지원합니다. (Contributed by Johannes Baiter in bpo-20968 [https://bugs.python.org/issue?@action=redirect&bpo=20968], and Håkan Lövdahl in bpo-23581 [https://bugs.python.org/issue?@action=redirect&bpo=23581] and bpo-23568 [https://bugs.python.org/issue?@action=redirect&bpo=23568].)

내장 이름을 패치 할 때 더는 create=True를 patch() 함수에 명시적으로 전달할 필요가 없습니다. (Contributed by Kushal Das in bpo-17660 [https://bugs.python.org/issue?@action=redirect&bpo=17660].)

urllib

새로운 request.HTTPPasswordMgrWithPriorAuth 클래스는 HTTP 기본 인증 자격 증명을 관리하도록 허용하여, 불필요한 401 응답 처리를 제거하거나, Authorization 헤더가 전송되지 않았으면 401 대신 404 응답을 반환하는 서버와 통신하기 위해 첫 번째 요청에서 자격 증명을 무조건 전송하도록 합니다. (Contributed by Matej Cepl in bpo-19494 [https://bugs.python.org/issue?@action=redirect&bpo=19494] and Akshit Khurana in bpo-7159 [https://bugs.python.org/issue?@action=redirect&bpo=7159].)

parse.urlencode() 함수에 대한 새로운 quote_via 인자는 필요하면 쿼리 부분의 인코딩을 제어하는 방법을 제공합니다. (Contributed by Samwyse and Arnon Yaari in bpo-13866 [https://bugs.python.org/issue?@action=redirect&bpo=13866].)

request.urlopen() 함수는 HTTPS 연결에 사용될 context 인자로 ssl.SSLContext 객체를 받아들입니다. (Contributed by Alex Gaynor in bpo-22366 [https://bugs.python.org/issue?@action=redirect&bpo=22366].)

parse.urljoin()은 상대 URL 확인을 위해 RFC 1808 [https://datatracker.ietf.org/doc/html/rfc1808.html]과 RFC 2396 [https://datatracker.ietf.org/doc/html/rfc2396.html] 대신에 RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html] 의미 체계를 사용하도록 갱신되었습니다. (Contributed by Demian Brecht and Senthil Kumaran in bpo-22118 [https://bugs.python.org/issue?@action=redirect&bpo=22118].)

wsgiref

headers.Headers 클래스 생성자의 headers 인자는 이제 선택 사항입니다. (Contributed by Pablo Torres Navarrete and SilentGhost in bpo-5800 [https://bugs.python.org/issue?@action=redirect&bpo=5800].)

xmlrpc

client.ServerProxy 클래스는 이제 컨텍스트 관리자 프로토콜을 지원합니다. (Contributed by Claudiu Popa in bpo-20627 [https://bugs.python.org/issue?@action=redirect&bpo=20627].)

client.ServerProxy 생성자는 이제 선택적 ssl.SSLContext 인스턴스를 받아들입니다. (Contributed by Alex Gaynor in bpo-22960 [https://bugs.python.org/issue?@action=redirect&bpo=22960].)

xml.sax

SAX 구문 분석기는 이제 xmlreader.InputSource 객체의 문자 스트림을 지원합니다. (Contributed by Serhiy Storchaka in bpo-2175 [https://bugs.python.org/issue?@action=redirect&bpo=2175].)

parseString()은 이제 str 인스턴스를 받아들입니다. (Contributed by Serhiy Storchaka in bpo-10590 [https://bugs.python.org/issue?@action=redirect&bpo=10590].)

zipfile

이제 ZIP 출력을 위치 변경할 수 없는(unseekable) 스트림에 쓸 수 있습니다. (Contributed by Serhiy Storchaka in bpo-23252 [https://bugs.python.org/issue?@action=redirect&bpo=23252].)

ZipFile.open() 메서드의 mode 인자는 이제 배타적 생성을 요청하는 "x"를 받아들입니다. (Contributed by Serhiy Storchaka in bpo-21717 [https://bugs.python.org/issue?@action=redirect&bpo=21717].)

기타 모듈 수준 변경

Many functions in the mmap, ossaudiodev, socket, ssl, and codecs modules now accept writable bytes-like objects. (Contributed by Serhiy Storchaka in bpo-23001 [https://bugs.python.org/issue?@action=redirect&bpo=23001].)

최적화

os.walk() 함수는 POSIX 시스템에서 3 에서 5배, 윈도우에서 7 에서 20배 빨라졌습니다. 이는 하부 readdir이나 FindFirstFile/FindNextFile 시스템 호출에서 파일 정보를 노출하는 새로운 os.scandir() 함수를 사용하여 수행되었습니다. (Contributed by Ben Hoyt with help from Victor Stinner in bpo-23605 [https://bugs.python.org/issue?@action=redirect&bpo=23605].)

(0 바이트로 채워진) bytes(int)의 구성이 더 빠르고 큰 객체에 대해 더 적은 메모리를 사용합니다. malloc() 대신 calloc()을 사용하여 이러한 객체에 대한 메모리를 할당합니다. (Contributed by Victor Stinner in bpo-21233 [https://bugs.python.org/issue?@action=redirect&bpo=21233].)

ipaddress IPv4Network와 IPv6Network에 대한 일부 연산(가령 subnets(), supernet(), summarize_address_range(), collapse_addresses())이 크게 빨라졌습니다. 속도 향상 범위는 3 에서 15배입니다. (Contributed by Antoine Pitrou, Michel Albert, and Markus in bpo-21486 [https://bugs.python.org/issue?@action=redirect&bpo=21486], bpo-21487 [https://bugs.python.org/issue?@action=redirect&bpo=21487], bpo-20826 [https://bugs.python.org/issue?@action=redirect&bpo=20826], bpo-23266 [https://bugs.python.org/issue?@action=redirect&bpo=23266].)

ipaddress 객체의 피클링은 훨씬 더 작은 출력을 생성하도록 최적화되었습니다. (Contributed by Serhiy Storchaka in bpo-23133 [https://bugs.python.org/issue?@action=redirect&bpo=23133].)

io.BytesIO에 대한 많은 연산이 이제 50%에서 100% 더 빨라졌습니다. (Contributed by Serhiy Storchaka in bpo-15381 [https://bugs.python.org/issue?@action=redirect&bpo=15381] and David Wilson in bpo-22003 [https://bugs.python.org/issue?@action=redirect&bpo=22003].)

이제 marshal.dumps() 함수가 더 빨라졌습니다: 일반 데이터에서는 버전 3과 4에서 65–85%, 버전 0부터 2에서 20–25%, 최상의 경우 최대 5배입니다. (Contributed by Serhiy Storchaka in bpo-20416 [https://bugs.python.org/issue?@action=redirect&bpo=20416] and bpo-23344 [https://bugs.python.org/issue?@action=redirect&bpo=23344].)

UTF-32 인코더는 이제 3 에서 7배 더 빨라졌습니다. (Contributed by Serhiy Storchaka in bpo-15027 [https://bugs.python.org/issue?@action=redirect&bpo=15027].)

이제 정규식이 최대 10% 더 빠르게 구문 분석됩니다. (Contributed by Serhiy Storchaka in bpo-19380 [https://bugs.python.org/issue?@action=redirect&bpo=19380].)

json.dumps() 함수는 ensure_ascii=False로 실행될 때 ensure_ascii=True와 같이 빠르게 실행되도록 최적화되었습니다. (Contributed by Naoki Inada in bpo-23206 [https://bugs.python.org/issue?@action=redirect&bpo=23206].)

PyObject_IsInstance()와 PyObject_IsSubclass() 함수는 두 번째 인자가 메타 클래스로 type을 갖는 일반적인 경우에 가속화되었습니다. (Contributed Georg Brandl by in bpo-22540 [https://bugs.python.org/issue?@action=redirect&bpo=22540].)

메서드 캐싱이 약간 개선되어, 일부 벤치마크에서 최대 5%의 성능 향상을 가져왔습니다. (Contributed by Antoine Pitrou in bpo-22847 [https://bugs.python.org/issue?@action=redirect&bpo=22847].)

random 모듈의 객체는 이제 64비트 빌드에서 50% 적은 메모리를 사용합니다. (Contributed by Serhiy Storchaka in bpo-23488 [https://bugs.python.org/issue?@action=redirect&bpo=23488].)

property() 게터 호출은 최대 25% 더 빠릅니다. (Contributed by Joe Jevnik in bpo-23910 [https://bugs.python.org/issue?@action=redirect&bpo=23910].)

fractions.Fraction의 인스턴스 화가 이제 최대 30% 빨라졌습니다. (Contributed by Stefan Behnel in bpo-22464 [https://bugs.python.org/issue?@action=redirect&bpo=22464].)

문자열 메서드 find(), rfind(), split(), partition() 및 in 문자열 연산자는 이제 1-문자 하위 문자열을 검색할 때 훨씬 더 빠릅니다. (Contributed by Serhiy Storchaka in bpo-23573 [https://bugs.python.org/issue?@action=redirect&bpo=23573].)

빌드와 C API 변경

새로운 calloc 함수가 추가되었습니다:

PyMem_RawCalloc(),

PyMem_Calloc(),

PyObject_Calloc().

(Contributed by Victor Stinner in bpo-21233 [https://bugs.python.org/issue?@action=redirect&bpo=21233].)

새로운 인코딩/디코딩 도우미 함수:

Py_DecodeLocale() (_Py_char2wchar()을 대체),

Py_EncodeLocale() (_Py_wchar2char()을 대체).

(Contributed by Victor Stinner in bpo-18395 [https://bugs.python.org/issue?@action=redirect&bpo=18395].)

유니코드 인코딩 에러를 \N{...} 이스케이프로 대체하는 새로운 PyCodec_NameReplaceErrors() 함수. (Contributed by Serhiy Storchaka in bpo-19676 [https://bugs.python.org/issue?@action=redirect&bpo=19676].)

A new PyErr_FormatV() function similar to PyErr_Format(), but accepts a va_list argument. (Contributed by Antoine Pitrou in bpo-18711 [https://bugs.python.org/issue?@action=redirect&bpo=18711].)

새로운 PyExc_RecursionError 예외. (Contributed by Georg Brandl in bpo-19235 [https://bugs.python.org/issue?@action=redirect&bpo=19235].)

PEP 489 [https://peps.python.org/pep-0489/] – 다단계 확장 모듈 초기화에 의해 도입된 새로운 PyModule_FromDefAndSpec(), PyModule_FromDefAndSpec2() 및 PyModule_ExecDef() 함수. (Contributed by Petr Viktorin in bpo-24268 [https://bugs.python.org/issue?@action=redirect&bpo=24268].)

행렬 곱셈을 수행하는 새로운 PyNumber_MatrixMultiply()와 PyNumber_InPlaceMatrixMultiply() 함수. (Contributed by Benjamin Peterson in bpo-21176 [https://bugs.python.org/issue?@action=redirect&bpo=21176]. 자세한 내용은 PEP 465 [https://peps.python.org/pep-0465/]를 참조하십시오.)

PyTypeObject.tp_finalize 슬롯은 이제 안정적인 ABI의 일부입니다.

Windows builds now require Microsoft Visual C++ 14.0, which is available as part of Visual Studio 2015 [https://visualstudio.microsoft.com/en/vs/older-downloads/#visual-studio-2015-and-other-products].

확장 모듈은 이제 일부 플랫폼에서 파일명에 플랫폼 정보 태그를 포함합니다 (태그는 선택 사항이며, CPython은 태그가 없더라도 확장을 임포트 하지만, 태그가 존재하고 일치하지 않으면 확장이 로드되지 않습니다):

리눅스에서, 확장 모듈 파일명은 .cpython-<major><minor>m-<architecture>-<os>.pyd로 끝납니다:

<major>는 파이썬 버전의 주 번호입니다; 파이썬 3.5의 경우 3입니다.

<minor>는 파이썬 버전의 부 번호입니다; 파이썬 3.5의 경우 5입니다.

<architecture>는 확장 모듈이 실행되도록 빌드된 하드웨어 아키텍처입니다. 가장 흔하게 32비트 Intel 플랫폼의 경우 i386 또는 64비트 Intel (및 AMD) 플랫폼의 경우 x86_64입니다.

<os>는 64비트 플랫폼에서 32비트 ABI와 통신하도록 빌드된 확장을 제외하고 항상 linux-gnu입니다. 이 경우 linux-gnu32(그리고 <architecture>는 x86_64가 됩니다)입니다.

윈도우에서, 확장 모듈 파일명은 <debug>.cp<major><minor>-<platform>.pyd로 끝납니다:

<major>는 파이썬 버전의 주 번호입니다; 파이썬 3.5의 경우 3입니다.

<minor>는 파이썬 버전의 부 번호입니다; 파이썬 3.5의 경우 5입니다.

<platform>은 확장 모듈이 빌드된 플랫폼으로, Win32 용 win32, Win64 용 win_amd64, 윈도우 Itanium 64 용 win_ia64 및 ARM 기반 윈도우 용 win_arm입니다.

디버그 모드로 빌드되면, <debug>는 _d가 되고 그렇지 않으면 공백이 됩니다.

OS X 플랫폼에서, 확장 모듈 파일명은 이제 -darwin.so로 끝납니다.

다른 모든 플랫폼에서, 확장 모듈 파일명은 파이썬 3.4에서와 같습니다.

폐지

새 키워드

async와 await는 변수, 클래스, 함수 또는 모듈 이름으로 사용하지 않는 것이 좋습니다. 파이썬 3.5에서 PEP 492 [https://peps.python.org/pep-0492/]에 의해 도입되었으며, 파이썬 3.7에서 정식 키워드가 될 것입니다.

폐지된 파이썬 동작

제너레이터 내에서 StopIteration 예외를 발생시키면 이제 조용한 PendingDeprecationWarning 을 생성하며, 이는 파이썬 3.6에서 조용하지 않은 폐지 경고가 되고 파이썬 3.7에서 RuntimeError를 트리거할 것입니다. 자세한 내용은 PEP 479: 제너레이터 내부에서의 StopIteration 처리 변경을 참조하십시오.

지원되지 않는 운영 체제

윈도우 XP는 더는 Microsoft에서 지원하지 않아서, PEP 11 [https://peps.python.org/pep-0011/]에 따라 CPython 3.5는 이 OS에서 더는 공식적으로 지원되지 않습니다.

폐지된 파이썬 모듈, 함수 및 메서드

formatter 모듈은 이제 완전히 폐지되었으며 파이썬 3.6에서 제거될 예정입니다.

asyncio.async() 함수는 폐지되었고 ensure_future()로 대체합니다.

The smtpd module has in the past always decoded the DATA portion of email messages using the utf-8 codec. This can now be controlled by the new decode_data keyword to SMTPServer. The default value is True, but this default is deprecated. Specify the decode_data keyword with an appropriate value to avoid the deprecation warning.

http.cookies.Morsel 객체의 key, value 및 coded_value에 값을 직접 대입하는 것은 폐지되었습니다. 대신 set() 메서드를 사용하십시오. 또한, set()의 문서화되지 않은 LegalChars 매개 변수는 폐지되었으며 이제 무시됩니다.

포맷 문자열을 키워드 인자 format_string으로 string.Formatter 클래스의 format() 메서드에 전달하는 것은 폐지되었습니다. (Contributed by Serhiy Storchaka in bpo-23671 [https://bugs.python.org/issue?@action=redirect&bpo=23671].)

platform.dist()와 platform.linux_distribution() 함수는 이제 폐지되었습니다. 리눅스 배포판은 자신을 설명하는 데 너무 많은 다른 방법을 사용하므로, 기능은 패키지에 남겨집니다. (Contributed by Vajrasky Kok and Berker Peksag in bpo-1322 [https://bugs.python.org/issue?@action=redirect&bpo=1322].)

이전에 문서화되지 않은 inspect.Signature의 from_function과 from_builtin 메서드는 폐지되었습니다. 대신 새로운 Signature.from_callable() 메서드를 사용하십시오. (Contributed by Yury Selivanov in bpo-24248 [https://bugs.python.org/issue?@action=redirect&bpo=24248].)

inspect.getargspec() 함수는 폐지되었으며 파이썬 3.6에서 제거될 예정입니다. (자세한 내용은 bpo-20438 [https://bugs.python.org/issue?@action=redirect&bpo=20438]을 참조하십시오.)

inspect getfullargspec(), getcallargs() 및 formatargspec() 함수는 폐지되었고 inspect.signature() API로 대체합니다. (Contributed by Yury Selivanov in bpo-20438 [https://bugs.python.org/issue?@action=redirect&bpo=20438].)

getargvalues()와 formatargvalues() 함수는 파이썬 3.5.0 릴리스에서 실수로 폐지된 것으로 표시되었습니다.

str 패턴이나 re.ASCII와 함께 re.LOCALE 플래그를 사용하는 것은 이제 폐지되었습니다. (Contributed by Serhiy Storchaka in bpo-22407 [https://bugs.python.org/issue?@action=redirect&bpo=22407].)

정규식 패턴과 치환 패턴에서 '\'와 ASCII 문자로 구성된 인식할 수 없는 특수 시퀀스를 사용하면 이제 폐지 경고가 발생하며 파이썬 3.6에서는 금지됩니다. (Contributed by Serhiy Storchaka in bpo-23622 [https://bugs.python.org/issue?@action=redirect&bpo=23622].)

unittest.TestLoader.loadTestsFromModule() 메서드의 문서화되지 않고 비공식적인 use_load_tests 기본 인자는 이제 폐지되었으며 무시됩니다. (Contributed by Robert Collins and Barry A. Warsaw in bpo-16662 [https://bugs.python.org/issue?@action=redirect&bpo=16662].)

제거

API 및 기능 제거

다음과 같은 더는 사용되지 않고 이전에 폐지된 API와 기능이 제거되었습니다:

__version__ 어트리뷰트가 이메일 패키지에서 삭제되었습니다. 이메일 코드는 오랫동안 표준 라이브러리와 별도로 배포되지 않았으며 __version__ 문자열은 지난 몇 번의 릴리스에서 갱신되지 않았습니다.

ftplib 모듈의 내부 Netrc 클래스는 3.4에서 폐지되었으며, 이제 제거되었습니다. (Contributed by Matt Chaput in bpo-6623 [https://bugs.python.org/issue?@action=redirect&bpo=6623].)

.pyo 파일의 개념이 제거되었습니다.

잠정적 asyncio 모듈의 JoinableQueue 클래스는 3.4.4에서 폐지되었으며 이제 제거되었습니다. (Contributed by A. Jesse Jiryu Davis in bpo-23464 [https://bugs.python.org/issue?@action=redirect&bpo=23464].)

파이썬 3.5로 이식하기

이 섹션은 코드 변경이 필요할 수 있는 이전에 설명한 변경 사항과 기타 버그 수정을 나열합니다.

파이썬 동작의 변경

부주의로 인해, 이전 파이썬 버전은 다음 문법을 잘못 수락했습니다:

f(1 for x in [1], *args)
f(1 for x in [1], **kwargs)

함수에 대한 유일한 인자가 아닌 경우 제너레이터 표현식을 괄호로 묶어야 하므로, 파이썬 3.5는 이제 SyntaxError를 올바르게 발생시킵니다.

파이썬 API의 변경

PEP 475 [https://peps.python.org/pep-0475/]: 시스템 호출은 시그널에 의해 중단될 때 파이썬 시그널 처리기가 예외를 발생시키지 않으면 이제 InterruptedError를 발생시키는 대신 재시도됩니다.

파이썬 3.5 이전에는, datetime.time 객체가 UTC로 자정을 나타내면 거짓으로 간주했습니다. 이 동작은 모호하고 에러가 발생하기 쉬운 것으로 간주하여 파이썬 3.5에서 제거되었습니다. 자세한 내용은 bpo-13936 [https://bugs.python.org/issue?@action=redirect&bpo=13936]을 참조하십시오.

The ssl.SSLSocket.send() method now raises either ssl.SSLWantReadError or ssl.SSLWantWriteError on a non-blocking socket if the operation would block. Previously, it would return 0. (Contributed by Nikolaus Rath in bpo-20951 [https://bugs.python.org/issue?@action=redirect&bpo=20951].)

제너레이터의 __name__ 어트리뷰트는 이제 코드 이름에서 설정되는 대신 함수 이름에서 설정됩니다. 코드 이름을 꺼내려면 gen.gi_code.co_name을 사용하십시오. 제너레이터에는 이제 제너레이터의 표현(repr(gen))에 사용되는 정규화된 이름인 새로운 __qualname__ 어트리뷰트도 있습니다. (Contributed by Victor Stinner in bpo-21205 [https://bugs.python.org/issue?@action=redirect&bpo=21205].)

The deprecated “strict” mode and argument of HTMLParser, HTMLParser.error(), and the HTMLParserError exception have been removed. (Contributed by Ezio Melotti in bpo-15114 [https://bugs.python.org/issue?@action=redirect&bpo=15114].) The convert_charrefs argument of HTMLParser is now True by default. (Contributed by Berker Peksag in bpo-21047 [https://bugs.python.org/issue?@action=redirect&bpo=21047].)

공식적으로 API의 일부는 아니지만, 이전에 “‘sometype’ does not support the buffer protocol” 형식이었던 에러 메시지는 이제 “a bytes-like object is required, not ‘sometype’” 형식임을 이식의 목적(즉: 테스트 수선)을 위해 유의할 필요가 있습니다. (Contributed by Ezio Melotti in bpo-16518 [https://bugs.python.org/issue?@action=redirect&bpo=16518].)

현재 디렉터리가 더는 존재하지 않는 디렉터리로 설정되면 FileNotFoundError 가 더는 발생하지 않고 대신 find_spec()이 sys.path_importer_cache에서 None을 캐싱하지 않고 None을 반환합니다. 이는 일반적일 때와 다릅니다 (bpo-22834 [https://bugs.python.org/issue?@action=redirect&bpo=22834]).

http.client와 http.server의 HTTP 상태 코드와 메시지는 공통 HTTPStatus 열거형으로 리팩토링 되었습니다. http.client와 http.server의 값은 이전 버전과의 호환성을 위해 계속 사용할 수 있습니다. (Contributed by Demian Brecht in bpo-21793 [https://bugs.python.org/issue?@action=redirect&bpo=21793].)

임포트 로더가 importlib.machinery.Loader.exec_module()을 정의할 때 이제 create_module()도 정의해야 합니다 (지금은 DeprecationWarning를 발생시키고, 파이썬 3.6에서는 에러가 될 것입니다). 로더가 importlib.abc.Loader에서 상속하면 할 일이 없습니다. 그렇지 않으면 단순히 None을 반환하는 create_module()을 정의합니다. (Contributed by Brett Cannon in bpo-23014 [https://bugs.python.org/issue?@action=redirect&bpo=23014].)

re.split() 함수는 항상 빈 패턴 일치를 무시해서, "x*" 패턴은 "x+"와 같게 작동하고, "\b" 패턴은 절대 작동하지 않습니다. 이제 re.split()은 패턴이 빈 문자열과 일치 할 수 있으면 경고를 발생시킵니다. 호환성을 위해, 절대 빈 문자열과 일치하지 않는 패턴을 사용하십시오 (예를 들어 "x*" 대신 "x+"). 빈 문자열과만 일치 할 수 있는 패턴(가령 "\b")은 이제 에러를 발생시킵니다. (Contributed by Serhiy Storchaka in bpo-22818 [https://bugs.python.org/issue?@action=redirect&bpo=22818].)

http.cookies.Morsel 딕셔너리류 인터페이스가 자체 일관성이 있도록 만들었습니다: 이제 Morsel 비교는 key와 value를 고려하고, copy()는 이제 dict가 아닌 Morsel 인스턴스를 생성하며, update()는 이제 업데이트 딕셔너리의 키 중 하나라도 잘못되면 예외를 발생시킵니다. 또한, set()의 문서화되지 않은 LegalChars 매개 변수는 폐지되었으며 이제 무시됩니다. (Contributed by Demian Brecht in bpo-2211 [https://bugs.python.org/issue?@action=redirect&bpo=2211].)

PEP 488 [https://peps.python.org/pep-0488/] has removed .pyo files from Python and introduced the optional opt- tag in .pyc file names. The importlib.util.cache_from_source() has gained an optimization parameter to help control the opt- tag. Because of this, the debug_override parameter of the function is now deprecated. .pyo files are also no longer supported as a file argument to the Python interpreter and thus serve no purpose when distributed on their own (i.e. sourceless code distribution). Due to the fact that the magic number for bytecode has changed in Python 3.5, all old .pyo files from previous versions of Python are invalid regardless of this PEP.

The socket module now exports the CAN_RAW_FD_FRAMES constant on linux 3.6 and greater.

ssl.cert_time_to_seconds() 함수는 이제 입력 시간을 RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html]에 따라 현지 시간이 아닌 UTC로 해석합니다. 또한, 반환 값은 항상 int입니다. (Contributed by Akira Li in bpo-19940 [https://bugs.python.org/issue?@action=redirect&bpo=19940].)

pygettext.py 도구는 이제 POT-Creation-Date 헤더의 시간대에 표준 +NNNN 형식을 사용합니다.

smtplib 모듈은 이제 디버그 출력을 위해 이전 모듈 수준 stderr 변수 대신 sys.stderr을 사용합니다. (테스트) 프로그램이 디버그 출력을 캡처하기 위해 모듈 수준 변수를 패치 하는 데 의존하면, 대신 sys.stderr을 캡처하도록 갱신해야 합니다.

str.startswith()와 str.endswith() 메서드는 빈 문자열을 찾고 인덱스가 완전히 범위를 벗어났을 때 더는 True를 반환하지 않습니다. (Contributed by Serhiy Storchaka in bpo-24284 [https://bugs.python.org/issue?@action=redirect&bpo=24284].)

inspect.getdoc() 함수는 이제 베이스 클래스에서 상속된 설명서 문자열을 반환합니다. 상속된 설명서가 적절하면 설명서 문자열을 더는 복제할 필요가 없습니다. 상속된 문자열을 억제하려면, 빈 문자열을 지정해야 합니다 (또는 설명서를 채울 수 있습니다). 이 변경 사항은 pydoc 모듈과 help() 함수의 출력에 영향을 줍니다. (Contributed by Serhiy Storchaka in bpo-15582 [https://bugs.python.org/issue?@action=redirect&bpo=15582].)

중첩된 functools.partial() 호출은 이제 평활화됩니다. 이전 동작에 의존한다면, 이제 functools.partial() 객체에 어트리뷰트를 추가하거나 functools.partial()의 서브 클래스를 만들 수 있습니다. (Contributed by Alexander Belopolsky in bpo-7830 [https://bugs.python.org/issue?@action=redirect&bpo=7830].)

C API의 변경

The undocumented format member of the (non-public) PyMemoryViewObject structure has been removed. All extensions relying on the relevant parts in memoryobject.h must be rebuilt.

PyMemAllocator 구조체는 PyMemAllocatorEx 로 이름이 바뀌었고 새로운 calloc 필드가 추가되었습니다.

Removed non-documented macro PyObject_REPR() which leaked references. Use format character %R in PyUnicode_FromFormat()-like functions to format the repr() of the object. (Contributed by Serhiy Storchaka in bpo-22453 [https://bugs.python.org/issue?@action=redirect&bpo=22453].)

Because the lack of the __module__ attribute breaks pickling and introspection, a deprecation warning is now raised for builtin types without the __module__ attribute. This will be an AttributeError in the future. (Contributed by Serhiy Storchaka in bpo-20204 [https://bugs.python.org/issue?@action=redirect&bpo=20204].)

As part of the PEP 492 [https://peps.python.org/pep-0492/] implementation, the tp_reserved slot of PyTypeObject was replaced with a tp_as_async slot. Refer to 코루틴 객체 for new types, structures and functions.

파이썬 3.5.4의 주목할만한 변경 사항

새로운 make regen-all 빌드 대상

교차 컴파일을 단순화하고, 기존 버전의 파이썬이 이미 사용할 수 있어야 한다는 요구 사항 없이 CPython을 안정적으로 컴파일 할 수 있도록, autotools 기반 빌드 시스템은 더는 파일 수정 시간을 기반으로 생성된 파일을 묵시적으로 재컴파일하려고 시도하지 않습니다.

대신, 원할 때 이러한 파일을 강제로 재생성하기 위해 새로운 make regen-all 명령이 추가되었습니다 (예를 들어 사전 생성된 버전을 기반으로 파이썬의 초기 버전이 이미 빌드된 후).

보다 선택적 재생성 대상도 정의됩니다 - 자세한 내용은 Makefile.pre.in [https://github.com/python/cpython/tree/main/Makefile.pre.in]을 참조하십시오.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

Added in version 3.5.4.

make touch 빌드 대상 제거

수정 시간을 갱신하여 생성된 파일의 묵시적 재생성을 요청하는 데 이전에 사용된 make touch 빌드 대상이 제거되었습니다.

새로운 make regen-all 대상으로 대체되었습니다.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

버전 3.5.4에서 변경.

What’s New In Python 3.4

Author:

R. David Murray <rdmurray@bitdance.com> (Editor)

This article explains the new features in Python 3.4, compared to 3.3. Python 3.4 was released on March 16, 2014. For full details, see the changelog [https://docs.python.org/3.4/whatsnew/changelog.html].

더 보기

PEP 429 [https://peps.python.org/pep-0429/] – Python 3.4 Release Schedule

Summary – Release Highlights

New syntax features:

No new syntax features were added in Python 3.4.

Other new features:

pip should always be available (PEP 453 [https://peps.python.org/pep-0453/]).

Newly created file descriptors are non-inheritable (PEP 446 [https://peps.python.org/pep-0446/]).

command line option for isolated mode (bpo-16499 [https://bugs.python.org/issue?@action=redirect&bpo=16499]).

improvements in the handling of codecs that are not text encodings (multiple issues).

A ModuleSpec Type for the Import System (PEP 451 [https://peps.python.org/pep-0451/]). (Affects importer authors.)

The marshal format has been made more compact and efficient (bpo-16475 [https://bugs.python.org/issue?@action=redirect&bpo=16475]).

New library modules:

asyncio: New provisional API for asynchronous IO (PEP 3156 [https://peps.python.org/pep-3156/]).

ensurepip: Bootstrapping the pip installer (PEP 453 [https://peps.python.org/pep-0453/]).

enum: Support for enumeration types (PEP 435 [https://peps.python.org/pep-0435/]).

pathlib: Object-oriented filesystem paths (PEP 428 [https://peps.python.org/pep-0428/]).

selectors: High-level and efficient I/O multiplexing, built upon the select module primitives (part of PEP 3156 [https://peps.python.org/pep-3156/]).

statistics: A basic numerically stable statistics library (PEP 450 [https://peps.python.org/pep-0450/]).

tracemalloc: Trace Python memory allocations (PEP 454 [https://peps.python.org/pep-0454/]).

Significantly improved library modules:

Single-dispatch generic functions in functools (PEP 443 [https://peps.python.org/pep-0443/]).

New pickle protocol 4 (PEP 3154 [https://peps.python.org/pep-3154/]).

multiprocessing now has an option to avoid using os.fork on Unix (bpo-8713 [https://bugs.python.org/issue?@action=redirect&bpo=8713]).

email has a new submodule, contentmanager, and a new Message subclass (EmailMessage) that simplify MIME handling (bpo-18891 [https://bugs.python.org/issue?@action=redirect&bpo=18891]).

The inspect and pydoc modules are now capable of correct introspection of a much wider variety of callable objects, which improves the output of the Python help() system.

The ipaddress module API has been declared stable

Security improvements:

Secure and interchangeable hash algorithm (PEP 456 [https://peps.python.org/pep-0456/]).

Make newly created file descriptors non-inheritable (PEP 446 [https://peps.python.org/pep-0446/]) to avoid leaking file descriptors to child processes.

New command line option for isolated mode, (bpo-16499 [https://bugs.python.org/issue?@action=redirect&bpo=16499]).

multiprocessing now has an option to avoid using os.fork on Unix. spawn and forkserver are more secure because they avoid sharing data with child processes.

multiprocessing child processes on Windows no longer inherit all of the parent’s inheritable handles, only the necessary ones.

A new hashlib.pbkdf2_hmac() function provides the PKCS#5 password-based key derivation function 2 [https://en.wikipedia.org/wiki/PBKDF2].

TLSv1.1 and TLSv1.2 support for ssl.

Retrieving certificates from the Windows system cert store support for ssl.

Server-side SNI (Server Name Indication) support for ssl.

The ssl.SSLContext class has a lot of improvements.

All modules in the standard library that support SSL now support server certificate verification, including hostname matching (ssl.match_hostname()) and CRLs (Certificate Revocation lists, see ssl.SSLContext.load_verify_locations()).

CPython implementation improvements:

Safe object finalization (PEP 442 [https://peps.python.org/pep-0442/]).

Leveraging PEP 442 [https://peps.python.org/pep-0442/], in most cases module globals are no longer set to None during finalization (bpo-18214 [https://bugs.python.org/issue?@action=redirect&bpo=18214]).

Configurable memory allocators (PEP 445 [https://peps.python.org/pep-0445/]).

Argument Clinic (PEP 436 [https://peps.python.org/pep-0436/]).

Please read on for a comprehensive list of user-facing changes, including many other smaller improvements, CPython optimizations, deprecations, and potential porting issues.

New Features

PEP 453: Explicit Bootstrapping of PIP in Python Installations

Bootstrapping pip By Default

The new ensurepip module (defined in PEP 453 [https://peps.python.org/pep-0453/]) provides a standard cross-platform mechanism to bootstrap the pip installer into Python installations and virtual environments. The version of pip included with Python 3.4.0 is pip 1.5.4, and future 3.4.x maintenance releases will update the bundled version to the latest version of pip that is available at the time of creating the release candidate.

By default, the commands pipX and pipX.Y will be installed on all platforms (where X.Y stands for the version of the Python installation), along with the pip Python package and its dependencies. On Windows and in virtual environments on all platforms, the unversioned pip command will also be installed. On other platforms, the system wide unversioned pip command typically refers to the separately installed Python 2 version.

The pyvenv command line utility and the venv module make use of the ensurepip module to make pip readily available in virtual environments. When using the command line utility, pip is installed by default, while when using the venv module API installation of pip must be requested explicitly.

For CPython source builds on POSIX systems, the make install and make altinstall commands bootstrap pip by default. This behaviour can be controlled through configure options, and overridden through Makefile options.

On Windows and Mac OS X, the CPython installers now default to installing pip along with CPython itself (users may opt out of installing it during the installation process). Window users will need to opt in to the automatic PATH modifications to have pip available from the command line by default, otherwise it can still be accessed through the Python launcher for Windows as py -m pip.

As discussed in the PEP [https://peps.python.org/pep-0453/#recommendations-for-downstream-distributors] platform packagers may choose not to install these commands by default, as long as, when invoked, they provide clear and simple directions on how to install them on that platform (usually using the system package manager).

참고

To avoid conflicts between parallel Python 2 and Python 3 installations, only the versioned pip3 and pip3.4 commands are bootstrapped by default when ensurepip is invoked directly - the --default-pip option is needed to also request the unversioned pip command. pyvenv and the Windows installer ensure that the unqualified pip command is made available in those environments, and pip can always be invoked via the -m switch rather than directly to avoid ambiguity on systems with multiple Python installations.

Documentation Changes

As part of this change, the 파이썬 모듈 설치하기 and 파이썬 모듈 배포하기 sections of the documentation have been completely redesigned as short getting started and FAQ documents. Most packaging documentation has now been moved out to the Python Packaging Authority maintained Python Packaging User Guide [https://packaging.python.org] and the documentation of the individual projects.

However, as this migration is currently still incomplete, the legacy versions of those guides remaining available as Building C and C++ Extensions with setuptools and Building C and C++ Extensions with setuptools.

더 보기

PEP 453 [https://peps.python.org/pep-0453/] – Explicit bootstrapping of pip in Python installations

PEP written by Donald Stufft and Nick Coghlan, implemented by Donald Stufft, Nick Coghlan, Martin von Löwis and Ned Deily.

PEP 446: Newly Created File Descriptors Are Non-Inheritable

PEP 446 [https://peps.python.org/pep-0446/] makes newly created file descriptors non-inheritable. In general, this is the behavior an application will want: when launching a new process, having currently open files also open in the new process can lead to all sorts of hard to find bugs, and potentially to security issues.

However, there are occasions when inheritance is desired. To support these cases, the following new functions and methods are available:

os.get_inheritable(), os.set_inheritable()

os.get_handle_inheritable(), os.set_handle_inheritable()

socket.socket.get_inheritable(), socket.socket.set_inheritable()

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PEP 446 [https://peps.python.org/pep-0446/] – Make newly created file descriptors non-inheritable

PEP written and implemented by Victor Stinner.

Improvements to Codec Handling

Since it was first introduced, the codecs module has always been intended to operate as a type-neutral dynamic encoding and decoding system. However, its close coupling with the Python text model, especially the type restricted convenience methods on the builtin str, bytes and bytearray types, has historically obscured that fact.

As a key step in clarifying the situation, the codecs.encode() and codecs.decode() convenience functions are now properly documented in Python 2.7, 3.3 and 3.4. These functions have existed in the codecs module (and have been covered by the regression test suite) since Python 2.4, but were previously only discoverable through runtime introspection.

Unlike the convenience methods on str, bytes and bytearray, the codecs convenience functions support arbitrary codecs in both Python 2 and Python 3, rather than being limited to Unicode text encodings (in Python 3) or basestring <-> basestring conversions (in Python 2).

In Python 3.4, the interpreter is able to identify the known non-text encodings provided in the standard library and direct users towards these general purpose convenience functions when appropriate:

>>> b"abcdef".decode("hex")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
LookupError: 'hex' is not a text encoding; use codecs.decode() to handle arbitrary codecs

>>> "hello".encode("rot13")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
LookupError: 'rot13' is not a text encoding; use codecs.encode() to handle arbitrary codecs

>>> open("foo.txt", encoding="hex")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
LookupError: 'hex' is not a text encoding; use codecs.open() to handle arbitrary codecs

In a related change, whenever it is feasible without breaking backwards compatibility, exceptions raised during encoding and decoding operations are wrapped in a chained exception of the same type that mentions the name of the codec responsible for producing the error:

>>> import codecs

>>> codecs.decode(b"abcdefgh", "hex")
Traceback (most recent call last):
  File "/usr/lib/python3.4/encodings/hex_codec.py", line 20, in hex_decode
    return (binascii.a2b_hex(input), len(input))
binascii.Error: Non-hexadecimal digit found

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
binascii.Error: decoding with 'hex' codec failed (Error: Non-hexadecimal digit found)

>>> codecs.encode("hello", "bz2")
Traceback (most recent call last):
  File "/usr/lib/python3.4/encodings/bz2_codec.py", line 17, in bz2_encode
    return (bz2.compress(input), len(input))
  File "/usr/lib/python3.4/bz2.py", line 498, in compress
    return comp.compress(data) + comp.flush()
TypeError: 'str' does not support the buffer interface

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: encoding with 'bz2' codec failed (TypeError: 'str' does not support the buffer interface)

Finally, as the examples above show, these improvements have permitted the restoration of the convenience aliases for the non-Unicode codecs that were themselves restored in Python 3.2. This means that encoding binary data to and from its hexadecimal representation (for example) can now be written as:

>>> from codecs import encode, decode
>>> encode(b"hello", "hex")
b'68656c6c6f'
>>> decode(b"68656c6c6f", "hex")
b'hello'

The binary and text transforms provided in the standard library are detailed in 바이너리 변환 and 텍스트 변환.

(Contributed by Nick Coghlan in bpo-7475 [https://bugs.python.org/issue?@action=redirect&bpo=7475], bpo-17827 [https://bugs.python.org/issue?@action=redirect&bpo=17827], bpo-17828 [https://bugs.python.org/issue?@action=redirect&bpo=17828] and bpo-19619 [https://bugs.python.org/issue?@action=redirect&bpo=19619].)

PEP 451: A ModuleSpec Type for the Import System

PEP 451 [https://peps.python.org/pep-0451/] provides an encapsulation of the information about a module that the import machinery will use to load it (that is, a module specification). This helps simplify both the import implementation and several import-related APIs. The change is also a stepping stone for several future import-related improvements [https://mail.python.org/pipermail/python-dev/2013-November/130111.html].

The public-facing changes from the PEP are entirely backward-compatible. Furthermore, they should be transparent to everyone but importer authors. Key finder and loader methods have been deprecated, but they will continue working. New importers should use the new methods described in the PEP. Existing importers should be updated to implement the new methods. See the Deprecated section for a list of methods that should be replaced and their replacements.

Other Language Changes

Some smaller changes made to the core Python language are:

Unicode database updated to UCD version 6.3.

min() and max() now accept a default keyword-only argument that can be used to specify the value they return if the iterable they are evaluating has no elements. (Contributed by Julian Berman in bpo-18111 [https://bugs.python.org/issue?@action=redirect&bpo=18111].)

Module objects are now weakly referenceable.

Module __file__ attributes (and related values) should now always contain absolute paths by default, with the sole exception of __main__.__file__ when a script has been executed directly using a relative path. (Contributed by Brett Cannon in bpo-18416 [https://bugs.python.org/issue?@action=redirect&bpo=18416].)

All the UTF-* codecs (except UTF-7) now reject surrogates during both encoding and decoding unless the surrogatepass error handler is used, with the exception of the UTF-16 decoder (which accepts valid surrogate pairs) and the UTF-16 encoder (which produces them while encoding non-BMP characters). (Contributed by Victor Stinner, Kang-Hao (Kenny) Lu and Serhiy Storchaka in bpo-12892 [https://bugs.python.org/issue?@action=redirect&bpo=12892].)

New German EBCDIC codec cp273. (Contributed by Michael Bierenfeld and Andrew Kuchling in bpo-1097797 [https://bugs.python.org/issue?@action=redirect&bpo=1097797].)

New Ukrainian codec cp1125. (Contributed by Serhiy Storchaka in bpo-19668 [https://bugs.python.org/issue?@action=redirect&bpo=19668].)

bytes.join() and bytearray.join() now accept arbitrary buffer objects as arguments. (Contributed by Antoine Pitrou in bpo-15958 [https://bugs.python.org/issue?@action=redirect&bpo=15958].)

The int constructor now accepts any object that has an __index__ method for its base argument. (Contributed by Mark Dickinson in bpo-16772 [https://bugs.python.org/issue?@action=redirect&bpo=16772].)

Frame objects now have a clear() method that clears all references to local variables from the frame. (Contributed by Antoine Pitrou in bpo-17934 [https://bugs.python.org/issue?@action=redirect&bpo=17934].)

memoryview is now registered as a Sequence, and supports the reversed() builtin. (Contributed by Nick Coghlan and Claudiu Popa in bpo-18690 [https://bugs.python.org/issue?@action=redirect&bpo=18690] and bpo-19078 [https://bugs.python.org/issue?@action=redirect&bpo=19078].)

Signatures reported by help() have been modified and improved in several cases as a result of the introduction of Argument Clinic and other changes to the inspect and pydoc modules.

__length_hint__() is now part of the formal language specification (see PEP 424 [https://peps.python.org/pep-0424/]). (Contributed by Armin Ronacher in bpo-16148 [https://bugs.python.org/issue?@action=redirect&bpo=16148].)

New Modules

asyncio

The new asyncio module (defined in PEP 3156 [https://peps.python.org/pep-3156/]) provides a standard pluggable event loop model for Python, providing solid asynchronous IO support in the standard library, and making it easier for other event loop implementations to interoperate with the standard library and each other.

For Python 3.4, this module is considered a provisional API.

더 보기

PEP 3156 [https://peps.python.org/pep-3156/] – Asynchronous IO Support Rebooted: the “asyncio” Module

PEP written and implementation led by Guido van Rossum.

ensurepip

The new ensurepip module is the primary infrastructure for the PEP 453 [https://peps.python.org/pep-0453/] implementation. In the normal course of events end users will not need to interact with this module, but it can be used to manually bootstrap pip if the automated bootstrapping into an installation or virtual environment was declined.

ensurepip includes a bundled copy of pip, up-to-date as of the first release candidate of the release of CPython with which it ships (this applies to both maintenance releases and feature releases). ensurepip does not access the internet. If the installation has internet access, after ensurepip is run the bundled pip can be used to upgrade pip to a more recent release than the bundled one. (Note that such an upgraded version of pip is considered to be a separately installed package and will not be removed if Python is uninstalled.)

The module is named ensurepip because if called when pip is already installed, it does nothing. It also has an --upgrade option that will cause it to install the bundled copy of pip if the existing installed version of pip is older than the bundled copy.

enum

The new enum module (defined in PEP 435 [https://peps.python.org/pep-0435/]) provides a standard implementation of enumeration types, allowing other modules (such as socket) to provide more informative error messages and better debugging support by replacing opaque integer constants with backwards compatible enumeration values.

더 보기

PEP 435 [https://peps.python.org/pep-0435/] – Adding an Enum type to the Python standard library

PEP written by Barry Warsaw, Eli Bendersky and Ethan Furman, implemented by Ethan Furman.

pathlib

The new pathlib module offers classes representing filesystem paths with semantics appropriate for different operating systems. Path classes are divided between pure paths, which provide purely computational operations without I/O, and concrete paths, which inherit from pure paths but also provide I/O operations.

For Python 3.4, this module is considered a provisional API.

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PEP 428 [https://peps.python.org/pep-0428/] – The pathlib module – object-oriented filesystem paths

PEP written and implemented by Antoine Pitrou.

selectors

The new selectors module (created as part of implementing PEP 3156 [https://peps.python.org/pep-3156/]) allows high-level and efficient I/O multiplexing, built upon the select module primitives.

statistics

The new statistics module (defined in PEP 450 [https://peps.python.org/pep-0450/]) offers some core statistics functionality directly in the standard library. This module supports calculation of the mean, median, mode, variance and standard deviation of a data series.

더 보기

PEP 450 [https://peps.python.org/pep-0450/] – Adding A Statistics Module To The Standard Library

PEP written and implemented by Steven D’Aprano

tracemalloc

The new tracemalloc module (defined in PEP 454 [https://peps.python.org/pep-0454/]) is a debug tool to trace memory blocks allocated by Python. It provides the following information:

Trace where an object was allocated

Statistics on allocated memory blocks per filename and per line number: total size, number and average size of allocated memory blocks

Compute the differences between two snapshots to detect memory leaks

더 보기

PEP 454 [https://peps.python.org/pep-0454/] – Add a new tracemalloc module to trace Python memory allocations

PEP written and implemented by Victor Stinner

Improved Modules

abc

New function abc.get_cache_token() can be used to know when to invalidate caches that are affected by changes in the object graph. (Contributed by Łukasz Langa in bpo-16832 [https://bugs.python.org/issue?@action=redirect&bpo=16832].)

New class ABC has ABCMeta as its meta class. Using ABC as a base class has essentially the same effect as specifying metaclass=abc.ABCMeta, but is simpler to type and easier to read. (Contributed by Bruno Dupuis in bpo-16049 [https://bugs.python.org/issue?@action=redirect&bpo=16049].)

aifc

The getparams() method now returns a namedtuple rather than a plain tuple. (Contributed by Claudiu Popa in bpo-17818 [https://bugs.python.org/issue?@action=redirect&bpo=17818].)

aifc.open() now supports the context management protocol: when used in a with block, the close() method of the returned object will be called automatically at the end of the block. (Contributed by Serhiy Storchacha in bpo-16486 [https://bugs.python.org/issue?@action=redirect&bpo=16486].)

The writeframesraw() and writeframes() methods now accept any bytes-like object. (Contributed by Serhiy Storchaka in bpo-8311 [https://bugs.python.org/issue?@action=redirect&bpo=8311].)

argparse

The FileType class now accepts encoding and errors arguments, which are passed through to open(). (Contributed by Lucas Maystre in bpo-11175 [https://bugs.python.org/issue?@action=redirect&bpo=11175].)

audioop

audioop now supports 24-bit samples. (Contributed by Serhiy Storchaka in bpo-12866 [https://bugs.python.org/issue?@action=redirect&bpo=12866].)

New byteswap() function converts big-endian samples to little-endian and vice versa. (Contributed by Serhiy Storchaka in bpo-19641 [https://bugs.python.org/issue?@action=redirect&bpo=19641].)

All audioop functions now accept any bytes-like object. Strings are not accepted: they didn’t work before, now they raise an error right away. (Contributed by Serhiy Storchaka in bpo-16685 [https://bugs.python.org/issue?@action=redirect&bpo=16685].)

base64

The encoding and decoding functions in base64 now accept any bytes-like object in cases where it previously required a bytes or bytearray instance. (Contributed by Nick Coghlan in bpo-17839 [https://bugs.python.org/issue?@action=redirect&bpo=17839].)

New functions a85encode(), a85decode(), b85encode(), and b85decode() provide the ability to encode and decode binary data from and to Ascii85 and the git/mercurial Base85 formats, respectively. The a85 functions have options that can be used to make them compatible with the variants of the Ascii85 encoding, including the Adobe variant. (Contributed by Martin Morrison, the Mercurial project, Serhiy Storchaka, and Antoine Pitrou in bpo-17618 [https://bugs.python.org/issue?@action=redirect&bpo=17618].)

collections

The ChainMap.new_child() method now accepts an m argument specifying the child map to add to the chain. This allows an existing mapping and/or a custom mapping type to be used for the child. (Contributed by Vinay Sajip in bpo-16613 [https://bugs.python.org/issue?@action=redirect&bpo=16613].)

colorsys

The number of digits in the coefficients for the RGB — YIQ conversions have been expanded so that they match the FCC NTSC versions. The change in results should be less than 1% and may better match results found elsewhere. (Contributed by Brian Landers and Serhiy Storchaka in bpo-14323 [https://bugs.python.org/issue?@action=redirect&bpo=14323].)

contextlib

The new contextlib.suppress context manager helps to clarify the intent of code that deliberately suppresses exceptions from a single statement. (Contributed by Raymond Hettinger in bpo-15806 [https://bugs.python.org/issue?@action=redirect&bpo=15806] and Zero Piraeus in bpo-19266 [https://bugs.python.org/issue?@action=redirect&bpo=19266].)

The new contextlib.redirect_stdout() context manager makes it easier for utility scripts to handle inflexible APIs that write their output to sys.stdout and don’t provide any options to redirect it. Using the context manager, the sys.stdout output can be redirected to any other stream or, in conjunction with io.StringIO, to a string. The latter can be especially useful, for example, to capture output from a function that was written to implement a command line interface. It is recommended only for utility scripts because it affects the global state of sys.stdout. (Contributed by Raymond Hettinger in bpo-15805 [https://bugs.python.org/issue?@action=redirect&bpo=15805].)

The contextlib documentation has also been updated to include a discussion of the differences between single use, reusable and reentrant context managers.

dbm

dbm.open() objects now support the context management protocol. When used in a with statement, the close method of the database object will be called automatically at the end of the block. (Contributed by Claudiu Popa and Nick Coghlan in bpo-19282 [https://bugs.python.org/issue?@action=redirect&bpo=19282].)

dis

Functions show_code(), dis(), distb(), and disassemble() now accept a keyword-only file argument that controls where they write their output.

The dis module is now built around an Instruction class that provides object oriented access to the details of each individual bytecode operation.

A new method, get_instructions(), provides an iterator that emits the Instruction stream for a given piece of Python code. Thus it is now possible to write a program that inspects and manipulates a bytecode object in ways different from those provided by the dis module itself. For example:

>>> import dis
>>> for instr in dis.get_instructions(lambda x: x + 1):
...     print(instr.opname)
LOAD_FAST
LOAD_CONST
BINARY_ADD
RETURN_VALUE

The various display tools in the dis module have been rewritten to use these new components.

In addition, a new application-friendly class Bytecode provides an object-oriented API for inspecting bytecode in both in human-readable form and for iterating over instructions. The Bytecode constructor takes the same arguments that get_instruction() does (plus an optional current_offset), and the resulting object can be iterated to produce Instruction objects. But it also has a dis method, equivalent to calling dis on the constructor argument, but returned as a multi-line string:

>>> bytecode = dis.Bytecode(lambda x: x + 1, current_offset=3)
>>> for instr in bytecode:
...     print('{} ({})'.format(instr.opname, instr.opcode))
LOAD_FAST (124)
LOAD_CONST (100)
BINARY_ADD (23)
RETURN_VALUE (83)
>>> bytecode.dis().splitlines()
['  1           0 LOAD_FAST                0 (x)',
 '      -->     3 LOAD_CONST               1 (1)',
 '              6 BINARY_ADD',
 '              7 RETURN_VALUE']

Bytecode also has a class method, from_traceback(), that provides the ability to manipulate a traceback (that is, print(Bytecode.from_traceback(tb).dis()) is equivalent to distb(tb)).

(Contributed by Nick Coghlan, Ryan Kelly and Thomas Kluyver in bpo-11816 [https://bugs.python.org/issue?@action=redirect&bpo=11816] and Claudiu Popa in bpo-17916 [https://bugs.python.org/issue?@action=redirect&bpo=17916].)

New function stack_effect() computes the effect on the Python stack of a given opcode and argument, information that is not otherwise available. (Contributed by Larry Hastings in bpo-19722 [https://bugs.python.org/issue?@action=redirect&bpo=19722].)

doctest

A new option flag, FAIL_FAST, halts test running as soon as the first failure is detected. (Contributed by R. David Murray and Daniel Urban in bpo-16522 [https://bugs.python.org/issue?@action=redirect&bpo=16522].)

The doctest command line interface now uses argparse, and has two new options, -o and -f. -o allows doctest options to be specified on the command line, and -f is a shorthand for -o FAIL_FAST (to parallel the similar option supported by the unittest CLI). (Contributed by R. David Murray in bpo-11390 [https://bugs.python.org/issue?@action=redirect&bpo=11390].)

doctest will now find doctests in extension module __doc__ strings. (Contributed by Zachary Ware in bpo-3158 [https://bugs.python.org/issue?@action=redirect&bpo=3158].)

email

as_string() now accepts a policy argument to override the default policy of the message when generating a string representation of it. This means that as_string can now be used in more circumstances, instead of having to create and use a generator in order to pass formatting parameters to its flatten method. (Contributed by R. David Murray in bpo-18600 [https://bugs.python.org/issue?@action=redirect&bpo=18600].)

New method as_bytes() added to produce a bytes representation of the message in a fashion similar to how as_string produces a string representation. It does not accept the maxheaderlen argument, but does accept the unixfrom and policy arguments. The Message __bytes__() method calls it, meaning that bytes(mymsg) will now produce the intuitive result: a bytes object containing the fully formatted message. (Contributed by R. David Murray in bpo-18600 [https://bugs.python.org/issue?@action=redirect&bpo=18600].)

The Message.set_param() message now accepts a replace keyword argument. When specified, the associated header will be updated without changing its location in the list of headers. For backward compatibility, the default is False. (Contributed by R. David Murray in bpo-18891 [https://bugs.python.org/issue?@action=redirect&bpo=18891].)

A pair of new subclasses of Message have been added (EmailMessage and MIMEPart), along with a new sub-module, contentmanager and a new policy attribute content_manager. All documentation is currently in the new module, which is being added as part of email’s new provisional API. These classes provide a number of new methods that make extracting content from and inserting content into email messages much easier. For details, see the contentmanager documentation and the email: 예제. These API additions complete the bulk of the work that was planned as part of the email6 project. The currently provisional API is scheduled to become final in Python 3.5 (possibly with a few minor additions in the area of error handling). (Contributed by R. David Murray in bpo-18891 [https://bugs.python.org/issue?@action=redirect&bpo=18891].)

filecmp

A new clear_cache() function provides the ability to clear the filecmp comparison cache, which uses os.stat() information to determine if the file has changed since the last compare. This can be used, for example, if the file might have been changed and re-checked in less time than the resolution of a particular filesystem’s file modification time field. (Contributed by Mark Levitt in bpo-18149 [https://bugs.python.org/issue?@action=redirect&bpo=18149].)

New module attribute DEFAULT_IGNORES provides the list of directories that are used as the default value for the ignore parameter of the dircmp() function. (Contributed by Eli Bendersky in bpo-15442 [https://bugs.python.org/issue?@action=redirect&bpo=15442].)

functools

The new partialmethod() descriptor brings partial argument application to descriptors, just as partial() provides for normal callables. The new descriptor also makes it easier to get arbitrary callables (including partial() instances) to behave like normal instance methods when included in a class definition. (Contributed by Alon Horev and Nick Coghlan in bpo-4331 [https://bugs.python.org/issue?@action=redirect&bpo=4331].)

The new singledispatch() decorator brings support for single-dispatch generic functions to the Python standard library. Where object oriented programming focuses on grouping multiple operations on a common set of data into a class, a generic function focuses on grouping multiple implementations of an operation that allows it to work with different kinds of data.

더 보기

PEP 443 [https://peps.python.org/pep-0443/] – Single-dispatch generic functions

PEP written and implemented by Łukasz Langa.

total_ordering() now supports a return value of NotImplemented from the underlying comparison function. (Contributed by Katie Miller in bpo-10042 [https://bugs.python.org/issue?@action=redirect&bpo=10042].)

A pure-python version of the partial() function is now in the stdlib; in CPython it is overridden by the C accelerated version, but it is available for other implementations to use. (Contributed by Brian Thorne in bpo-12428 [https://bugs.python.org/issue?@action=redirect&bpo=12428].)

gc

New function get_stats() returns a list of three per-generation dictionaries containing the collections statistics since interpreter startup. (Contributed by Antoine Pitrou in bpo-16351 [https://bugs.python.org/issue?@action=redirect&bpo=16351].)

glob

A new function escape() provides a way to escape special characters in a filename so that they do not become part of the globbing expansion but are instead matched literally. (Contributed by Serhiy Storchaka in bpo-8402 [https://bugs.python.org/issue?@action=redirect&bpo=8402].)

hashlib

A new hashlib.pbkdf2_hmac() function provides the PKCS#5 password-based key derivation function 2 [https://en.wikipedia.org/wiki/PBKDF2]. (Contributed by Christian Heimes in bpo-18582 [https://bugs.python.org/issue?@action=redirect&bpo=18582].)

The name attribute of hashlib hash objects is now a formally supported interface. It has always existed in CPython’s hashlib (although it did not return lower case names for all supported hashes), but it was not a public interface and so some other Python implementations have not previously supported it. (Contributed by Jason R. Coombs in bpo-18532 [https://bugs.python.org/issue?@action=redirect&bpo=18532].)

hmac

hmac now accepts bytearray as well as bytes for the key argument to the new() function, and the msg parameter to both the new() function and the update() method now accepts any type supported by the hashlib module. (Contributed by Jonas Borgström in bpo-18240 [https://bugs.python.org/issue?@action=redirect&bpo=18240].)

The digestmod argument to the hmac.new() function may now be any hash digest name recognized by hashlib. In addition, the current behavior in which the value of digestmod defaults to MD5 is deprecated: in a future version of Python there will be no default value. (Contributed by Christian Heimes in bpo-17276 [https://bugs.python.org/issue?@action=redirect&bpo=17276].)

With the addition of block_size and name attributes (and the formal documentation of the digest_size attribute), the hmac module now conforms fully to the PEP 247 [https://peps.python.org/pep-0247/] API. (Contributed by Christian Heimes in bpo-18775 [https://bugs.python.org/issue?@action=redirect&bpo=18775].)

html

New function unescape() function converts HTML5 character references to the corresponding Unicode characters. (Contributed by Ezio Melotti in bpo-2927 [https://bugs.python.org/issue?@action=redirect&bpo=2927].)

HTMLParser accepts a new keyword argument convert_charrefs that, when True, automatically converts all character references. For backward-compatibility, its value defaults to False, but it will change to True in a future version of Python, so you are invited to set it explicitly and update your code to use this new feature. (Contributed by Ezio Melotti in bpo-13633 [https://bugs.python.org/issue?@action=redirect&bpo=13633].)

The strict argument of HTMLParser is now deprecated. (Contributed by Ezio Melotti in bpo-15114 [https://bugs.python.org/issue?@action=redirect&bpo=15114].)

http

send_error() now accepts an optional additional explain parameter which can be used to provide an extended error description, overriding the hardcoded default if there is one. This extended error description will be formatted using the error_message_format attribute and sent as the body of the error response. (Contributed by Karl Cow in bpo-12921 [https://bugs.python.org/issue?@action=redirect&bpo=12921].)

The http.server command line interface now has a -b/--bind option that causes the server to listen on a specific address. (Contributed by Malte Swart in bpo-17764 [https://bugs.python.org/issue?@action=redirect&bpo=17764].)

idlelib and IDLE

Since idlelib implements the IDLE shell and editor and is not intended for import by other programs, it gets improvements with every release. See Lib/idlelib/NEWS.txt for a cumulative list of changes since 3.3.0, as well as changes made in future 3.4.x releases. This file is also available from the IDLE Help ‣ About IDLE dialog.

importlib

The InspectLoader ABC defines a new method, source_to_code() that accepts source data and a path and returns a code object. The default implementation is equivalent to compile(data, path, 'exec', dont_inherit=True). (Contributed by Eric Snow and Brett Cannon in bpo-15627 [https://bugs.python.org/issue?@action=redirect&bpo=15627].)

InspectLoader also now has a default implementation for the get_code() method. However, it will normally be desirable to override the default implementation for performance reasons. (Contributed by Brett Cannon in bpo-18072 [https://bugs.python.org/issue?@action=redirect&bpo=18072].)

The reload() function has been moved from imp to importlib as part of the imp module deprecation. (Contributed by Berker Peksag in bpo-18193 [https://bugs.python.org/issue?@action=redirect&bpo=18193].)

importlib.util now has a MAGIC_NUMBER attribute providing access to the bytecode version number. This replaces the get_magic() function in the deprecated imp module. (Contributed by Brett Cannon in bpo-18192 [https://bugs.python.org/issue?@action=redirect&bpo=18192].)

New importlib.util functions cache_from_source() and source_from_cache() replace the same-named functions in the deprecated imp module. (Contributed by Brett Cannon in bpo-18194 [https://bugs.python.org/issue?@action=redirect&bpo=18194].)

The importlib bootstrap NamespaceLoader now conforms to the InspectLoader ABC, which means that runpy and python -m can now be used with namespace packages. (Contributed by Brett Cannon in bpo-18058 [https://bugs.python.org/issue?@action=redirect&bpo=18058].)

importlib.util has a new function decode_source() that decodes source from bytes using universal newline processing. This is useful for implementing InspectLoader.get_source() methods.

importlib.machinery.ExtensionFileLoader now has a get_filename() method. This was inadvertently omitted in the original implementation. (Contributed by Eric Snow in bpo-19152 [https://bugs.python.org/issue?@action=redirect&bpo=19152].)

inspect

The inspect module now offers a basic command line interface to quickly display source code and other information for modules, classes and functions. (Contributed by Claudiu Popa and Nick Coghlan in bpo-18626 [https://bugs.python.org/issue?@action=redirect&bpo=18626].)

unwrap() makes it easy to unravel wrapper function chains created by functools.wraps() (and any other API that sets the __wrapped__ attribute on a wrapper function). (Contributed by Daniel Urban, Aaron Iles and Nick Coghlan in bpo-13266 [https://bugs.python.org/issue?@action=redirect&bpo=13266].)

As part of the implementation of the new enum module, the inspect module now has substantially better support for custom __dir__ methods and dynamic class attributes provided through metaclasses. (Contributed by Ethan Furman in bpo-18929 [https://bugs.python.org/issue?@action=redirect&bpo=18929] and bpo-19030 [https://bugs.python.org/issue?@action=redirect&bpo=19030].)

getfullargspec() and getargspec() now use the signature() API. This allows them to support a much broader range of callables, including those with __signature__ attributes, those with metadata provided by argument clinic, functools.partial() objects and more. Note that, unlike signature(), these functions still ignore __wrapped__ attributes, and report the already bound first argument for bound methods, so it is still necessary to update your code to use signature() directly if those features are desired. (Contributed by Yury Selivanov in bpo-17481 [https://bugs.python.org/issue?@action=redirect&bpo=17481].)

signature() now supports duck types of CPython functions, which adds support for functions compiled with Cython. (Contributed by Stefan Behnel and Yury Selivanov in bpo-17159 [https://bugs.python.org/issue?@action=redirect&bpo=17159].)

ipaddress

ipaddress was added to the standard library in Python 3.3 as a provisional API. With the release of Python 3.4, this qualification has been removed: ipaddress is now considered a stable API, covered by the normal standard library requirements to maintain backwards compatibility.

A new is_global property is True if an address is globally routeable. (Contributed by Peter Moody in bpo-17400 [https://bugs.python.org/issue?@action=redirect&bpo=17400].)

logging

The TimedRotatingFileHandler has a new atTime parameter that can be used to specify the time of day when rollover should happen. (Contributed by Ronald Oussoren in bpo-9556 [https://bugs.python.org/issue?@action=redirect&bpo=9556].)

SocketHandler and DatagramHandler now support Unix domain sockets (by setting port to None). (Contributed by Vinay Sajip in commit ce46195b56a9.)

fileConfig() now accepts a configparser.RawConfigParser subclass instance for the fname parameter. This facilitates using a configuration file when logging configuration is just a part of the overall application configuration, or where the application modifies the configuration before passing it to fileConfig(). (Contributed by Vinay Sajip in bpo-16110 [https://bugs.python.org/issue?@action=redirect&bpo=16110].)

Logging configuration data received from a socket via the logging.config.listen() function can now be validated before being processed by supplying a verification function as the argument to the new verify keyword argument. (Contributed by Vinay Sajip in bpo-15452 [https://bugs.python.org/issue?@action=redirect&bpo=15452].)

marshal

The default marshal version has been bumped to 3. The code implementing the new version restores the Python2 behavior of recording only one copy of interned strings and preserving the interning on deserialization, and extends this “one copy” ability to any object type (including handling recursive references). This reduces both the size of .pyc files and the amount of memory a module occupies in memory when it is loaded from a .pyc (or .pyo) file. (Contributed by Kristján Valur Jónsson in bpo-16475 [https://bugs.python.org/issue?@action=redirect&bpo=16475], with additional speedups by Antoine Pitrou in bpo-19219 [https://bugs.python.org/issue?@action=redirect&bpo=19219].)

mmap

mmap objects are now weakly referenceable. (Contributed by Valerie Lambert in bpo-4885 [https://bugs.python.org/issue?@action=redirect&bpo=4885].)

multiprocessing

On Unix two new start methods, spawn and forkserver, have been added for starting processes using multiprocessing. These make the mixing of processes with threads more robust, and the spawn method matches the semantics that multiprocessing has always used on Windows. New function get_all_start_methods() reports all start methods available on the platform, get_start_method() reports the current start method, and set_start_method() sets the start method. (Contributed by Richard Oudkerk in bpo-8713 [https://bugs.python.org/issue?@action=redirect&bpo=8713].)

multiprocessing also now has the concept of a context, which determines how child processes are created. New function get_context() returns a context that uses a specified start method. It has the same API as the multiprocessing module itself, so you can use it to create Pools and other objects that will operate within that context. This allows a framework and an application or different parts of the same application to use multiprocessing without interfering with each other. (Contributed by Richard Oudkerk in bpo-18999 [https://bugs.python.org/issue?@action=redirect&bpo=18999].)

Except when using the old fork start method, child processes no longer inherit unneeded handles/file descriptors from their parents (part of bpo-8713 [https://bugs.python.org/issue?@action=redirect&bpo=8713]).

multiprocessing now relies on runpy (which implements the -m switch) to initialise __main__ appropriately in child processes when using the spawn or forkserver start methods. This resolves some edge cases where combining multiprocessing, the -m command line switch, and explicit relative imports could cause obscure failures in child processes. (Contributed by Nick Coghlan in bpo-19946 [https://bugs.python.org/issue?@action=redirect&bpo=19946].)

operator

New function length_hint() provides an implementation of the specification for how the __length_hint__() special method should be used, as part of the PEP 424 [https://peps.python.org/pep-0424/] formal specification of this language feature. (Contributed by Armin Ronacher in bpo-16148 [https://bugs.python.org/issue?@action=redirect&bpo=16148].)

There is now a pure-python version of the operator module available for reference and for use by alternate implementations of Python. (Contributed by Zachary Ware in bpo-16694 [https://bugs.python.org/issue?@action=redirect&bpo=16694].)

os

There are new functions to get and set the inheritable flag of a file descriptor (os.get_inheritable(), os.set_inheritable()) or a Windows handle (os.get_handle_inheritable(), os.set_handle_inheritable()).

New function cpu_count() reports the number of CPUs available on the platform on which Python is running (or None if the count can’t be determined). The multiprocessing.cpu_count() function is now implemented in terms of this function). (Contributed by Trent Nelson, Yogesh Chaudhari, Victor Stinner, and Charles-François Natali in bpo-17914 [https://bugs.python.org/issue?@action=redirect&bpo=17914].)

os.path.samestat() is now available on the Windows platform (and the os.path.samefile() implementation is now shared between Unix and Windows). (Contributed by Brian Curtin in bpo-11939 [https://bugs.python.org/issue?@action=redirect&bpo=11939].)

os.path.ismount() now recognizes volumes mounted below a drive root on Windows. (Contributed by Tim Golden in bpo-9035 [https://bugs.python.org/issue?@action=redirect&bpo=9035].)

os.open() supports two new flags on platforms that provide them, O_PATH (un-opened file descriptor), and O_TMPFILE (unnamed temporary file; as of 3.4.0 release available only on Linux systems with a kernel version of 3.11 or newer that have uapi headers). (Contributed by Christian Heimes in bpo-18673 [https://bugs.python.org/issue?@action=redirect&bpo=18673] and Benjamin Peterson, respectively.)

pdb

pdb has been enhanced to handle generators, yield, and yield from in a more useful fashion. This is especially helpful when debugging asyncio based programs. (Contributed by Andrew Svetlov and Xavier de Gaye in bpo-16596 [https://bugs.python.org/issue?@action=redirect&bpo=16596].)

The print command has been removed from pdb, restoring access to the Python print() function from the pdb command line. Python2’s pdb did not have a print command; instead, entering print executed the print statement. In Python3 print was mistakenly made an alias for the pdb p command. p, however, prints the repr of its argument, not the str like the Python2 print command did. Worse, the Python3 pdb print command shadowed the Python3 print function, making it inaccessible at the pdb prompt. (Contributed by Connor Osborn in bpo-18764 [https://bugs.python.org/issue?@action=redirect&bpo=18764].)

pickle

pickle now supports (but does not use by default) a new pickle protocol, protocol 4. This new protocol addresses a number of issues that were present in previous protocols, such as the serialization of nested classes, very large strings and containers, and classes whose __new__() method takes keyword-only arguments. It also provides some efficiency improvements.

더 보기

PEP 3154 [https://peps.python.org/pep-3154/] – Pickle protocol 4

PEP written by Antoine Pitrou and implemented by Alexandre Vassalotti.

plistlib

plistlib now has an API that is similar to the standard pattern for stdlib serialization protocols, with new load(), dump(), loads(), and dumps() functions. (The older API is now deprecated.) In addition to the already supported XML plist format (FMT_XML), it also now supports the binary plist format (FMT_BINARY). (Contributed by Ronald Oussoren and others in bpo-14455 [https://bugs.python.org/issue?@action=redirect&bpo=14455].)

poplib

Two new methods have been added to poplib: capa(), which returns the list of capabilities advertised by the POP server, and stls(), which switches a clear-text POP3 session into an encrypted POP3 session if the POP server supports it. (Contributed by Lorenzo Catucci in bpo-4473 [https://bugs.python.org/issue?@action=redirect&bpo=4473].)

pprint

The pprint module’s PrettyPrinter class and its pformat(), and pprint() functions have a new option, compact, that controls how the output is formatted. Currently setting compact to True means that sequences will be printed with as many sequence elements as will fit within width on each (indented) line. (Contributed by Serhiy Storchaka in bpo-19132 [https://bugs.python.org/issue?@action=redirect&bpo=19132].)

Long strings are now wrapped using Python’s normal line continuation syntax. (Contributed by Antoine Pitrou in bpo-17150 [https://bugs.python.org/issue?@action=redirect&bpo=17150].)

pty

pty.spawn() now returns the status value from os.waitpid() on the child process, instead of None. (Contributed by Gregory P. Smith.)

pydoc

The pydoc module is now based directly on the inspect.signature() introspection API, allowing it to provide signature information for a wider variety of callable objects. This change also means that __wrapped__ attributes are now taken into account when displaying help information. (Contributed by Larry Hastings in bpo-19674 [https://bugs.python.org/issue?@action=redirect&bpo=19674].)

The pydoc module no longer displays the self parameter for already bound methods. Instead, it aims to always display the exact current signature of the supplied callable. (Contributed by Larry Hastings in bpo-20710 [https://bugs.python.org/issue?@action=redirect&bpo=20710].)

In addition to the changes that have been made to pydoc directly, its handling of custom __dir__ methods and various descriptor behaviours has also been improved substantially by the underlying changes in the inspect module.

As the help() builtin is based on pydoc, the above changes also affect the behaviour of help().

re

New fullmatch() function and regex.fullmatch() method anchor the pattern at both ends of the string to match. This provides a way to be explicit about the goal of the match, which avoids a class of subtle bugs where $ characters get lost during code changes or the addition of alternatives to an existing regular expression. (Contributed by Matthew Barnett in bpo-16203 [https://bugs.python.org/issue?@action=redirect&bpo=16203].)

The repr of regex objects now includes the pattern and the flags; the repr of match objects now includes the start, end, and the part of the string that matched. (Contributed by Hugo Lopes Tavares and Serhiy Storchaka in bpo-13592 [https://bugs.python.org/issue?@action=redirect&bpo=13592] and bpo-17087 [https://bugs.python.org/issue?@action=redirect&bpo=17087].)

resource

New prlimit() function, available on Linux platforms with a kernel version of 2.6.36 or later and glibc of 2.13 or later, provides the ability to query or set the resource limits for processes other than the one making the call. (Contributed by Christian Heimes in bpo-16595 [https://bugs.python.org/issue?@action=redirect&bpo=16595].)

On Linux kernel version 2.6.36 or later, there are also some new Linux specific constants: RLIMIT_MSGQUEUE, RLIMIT_NICE, RLIMIT_RTPRIO, RLIMIT_RTTIME, and RLIMIT_SIGPENDING. (Contributed by Christian Heimes in bpo-19324 [https://bugs.python.org/issue?@action=redirect&bpo=19324].)

On FreeBSD version 9 and later, there some new FreeBSD specific constants: RLIMIT_SBSIZE, RLIMIT_SWAP, and RLIMIT_NPTS. (Contributed by Claudiu Popa in bpo-19343 [https://bugs.python.org/issue?@action=redirect&bpo=19343].)

select

epoll objects now support the context management protocol. When used in a with statement, the close() method will be called automatically at the end of the block. (Contributed by Serhiy Storchaka in bpo-16488 [https://bugs.python.org/issue?@action=redirect&bpo=16488].)

devpoll objects now have fileno() and close() methods, as well as a new attribute closed. (Contributed by Victor Stinner in bpo-18794 [https://bugs.python.org/issue?@action=redirect&bpo=18794].)

shelve

Shelf instances may now be used in with statements, and will be automatically closed at the end of the with block. (Contributed by Filip Gruszczyński in bpo-13896 [https://bugs.python.org/issue?@action=redirect&bpo=13896].)

shutil

copyfile() now raises a specific Error subclass, SameFileError, when the source and destination are the same file, which allows an application to take appropriate action on this specific error. (Contributed by Atsuo Ishimoto and Hynek Schlawack in bpo-1492704 [https://bugs.python.org/issue?@action=redirect&bpo=1492704].)

smtpd

The SMTPServer and SMTPChannel classes now accept a map keyword argument which, if specified, is passed in to asynchat.async_chat as its map argument. This allows an application to avoid affecting the global socket map. (Contributed by Vinay Sajip in bpo-11959 [https://bugs.python.org/issue?@action=redirect&bpo=11959].)

smtplib

SMTPException is now a subclass of OSError, which allows both socket level errors and SMTP protocol level errors to be caught in one try/except statement by code that only cares whether or not an error occurred. (Contributed by Ned Jackson Lovely in bpo-2118 [https://bugs.python.org/issue?@action=redirect&bpo=2118].)

socket

The socket module now supports the CAN_BCM protocol on platforms that support it. (Contributed by Brian Thorne in bpo-15359 [https://bugs.python.org/issue?@action=redirect&bpo=15359].)

Socket objects have new methods to get or set their inheritable flag, get_inheritable() and set_inheritable().

The socket.AF_* and socket.SOCK_* constants are now enumeration values using the new enum module. This allows meaningful names to be printed during debugging, instead of integer “magic numbers”.

The AF_LINK constant is now available on BSD and OSX.

inet_pton() and inet_ntop() are now supported on Windows. (Contributed by Atsuo Ishimoto in bpo-7171 [https://bugs.python.org/issue?@action=redirect&bpo=7171].)

sqlite3

A new boolean parameter to the connect() function, uri, can be used to indicate that the database parameter is a uri (see the SQLite URI documentation [https://www.sqlite.org/uri.html]). (Contributed by poq in bpo-13773 [https://bugs.python.org/issue?@action=redirect&bpo=13773].)

ssl

PROTOCOL_TLSv1_1 and PROTOCOL_TLSv1_2 (TLSv1.1 and TLSv1.2 support) have been added; support for these protocols is only available if Python is linked with OpenSSL 1.0.1 or later. (Contributed by Michele Orrù and Antoine Pitrou in bpo-16692 [https://bugs.python.org/issue?@action=redirect&bpo=16692].)

New function create_default_context() provides a standard way to obtain an SSLContext whose settings are intended to be a reasonable balance between compatibility and security. These settings are more stringent than the defaults provided by the SSLContext constructor, and may be adjusted in the future, without prior deprecation, if best-practice security requirements change. The new recommended best practice for using stdlib libraries that support SSL is to use create_default_context() to obtain an SSLContext object, modify it if needed, and then pass it as the context argument of the appropriate stdlib API. (Contributed by Christian Heimes in bpo-19689 [https://bugs.python.org/issue?@action=redirect&bpo=19689].)

SSLContext method load_verify_locations() accepts a new optional argument cadata, which can be used to provide PEM or DER encoded certificates directly via strings or bytes, respectively. (Contributed by Christian Heimes in bpo-18138 [https://bugs.python.org/issue?@action=redirect&bpo=18138].)

New function get_default_verify_paths() returns a named tuple of the paths and environment variables that the set_default_verify_paths() method uses to set OpenSSL’s default cafile and capath. This can be an aid in debugging default verification issues. (Contributed by Christian Heimes in bpo-18143 [https://bugs.python.org/issue?@action=redirect&bpo=18143].)

SSLContext has a new method, cert_store_stats(), that reports the number of loaded X.509 certs, X.509 CA certs, and certificate revocation lists (crls), as well as a get_ca_certs() method that returns a list of the loaded CA certificates. (Contributed by Christian Heimes in bpo-18147 [https://bugs.python.org/issue?@action=redirect&bpo=18147].)

If OpenSSL 0.9.8 or later is available, SSLContext has a new attribute verify_flags that can be used to control the certificate verification process by setting it to some combination of the new constants VERIFY_DEFAULT, VERIFY_CRL_CHECK_LEAF, VERIFY_CRL_CHECK_CHAIN, or VERIFY_X509_STRICT. OpenSSL does not do any CRL verification by default. (Contributed by Christien Heimes in bpo-8813 [https://bugs.python.org/issue?@action=redirect&bpo=8813].)

New SSLContext method load_default_certs() loads a set of default “certificate authority” (CA) certificates from default locations, which vary according to the platform. It can be used to load both TLS web server authentication certificates (purpose=SERVER_AUTH) for a client to use to verify a server, and certificates for a server to use in verifying client certificates (purpose=CLIENT_AUTH). (Contributed by Christian Heimes in bpo-19292 [https://bugs.python.org/issue?@action=redirect&bpo=19292].)

Two new windows-only functions, enum_certificates() and enum_crls() provide the ability to retrieve certificates, certificate information, and CRLs from the Windows cert store. (Contributed by Christian Heimes in bpo-17134 [https://bugs.python.org/issue?@action=redirect&bpo=17134].)

Support for server-side SNI (Server Name Indication) using the new ssl.SSLContext.set_servername_callback() method. (Contributed by Daniel Black in bpo-8109 [https://bugs.python.org/issue?@action=redirect&bpo=8109].)

The dictionary returned by SSLSocket.getpeercert() contains additional X509v3 extension items: crlDistributionPoints, calIssuers, and OCSP URIs. (Contributed by Christian Heimes in bpo-18379 [https://bugs.python.org/issue?@action=redirect&bpo=18379].)

stat

The stat module is now backed by a C implementation in _stat. A C implementation is required as most of the values aren’t standardized and are platform-dependent. (Contributed by Christian Heimes in bpo-11016 [https://bugs.python.org/issue?@action=redirect&bpo=11016].)

The module supports new ST_MODE flags, S_IFDOOR, S_IFPORT, and S_IFWHT. (Contributed by Christian Hiemes in bpo-11016 [https://bugs.python.org/issue?@action=redirect&bpo=11016].)

struct

New function iter_unpack and a new struct.Struct.iter_unpack() method on compiled formats provide streamed unpacking of a buffer containing repeated instances of a given format of data. (Contributed by Antoine Pitrou in bpo-17804 [https://bugs.python.org/issue?@action=redirect&bpo=17804].)

subprocess

check_output() now accepts an input argument that can be used to provide the contents of stdin for the command that is run. (Contributed by Zack Weinberg in bpo-16624 [https://bugs.python.org/issue?@action=redirect&bpo=16624].)

getstatus() and getstatusoutput() now work on Windows. This change was actually inadvertently made in 3.3.4. (Contributed by Tim Golden in bpo-10197 [https://bugs.python.org/issue?@action=redirect&bpo=10197].)

sunau

The getparams() method now returns a namedtuple rather than a plain tuple. (Contributed by Claudiu Popa in bpo-18901 [https://bugs.python.org/issue?@action=redirect&bpo=18901].)

sunau.open() now supports the context management protocol: when used in a with block, the close method of the returned object will be called automatically at the end of the block. (Contributed by Serhiy Storchaka in bpo-18878 [https://bugs.python.org/issue?@action=redirect&bpo=18878].)

AU_write.setsampwidth() now supports 24 bit samples, thus adding support for writing 24 sample using the module. (Contributed by Serhiy Storchaka in bpo-19261 [https://bugs.python.org/issue?@action=redirect&bpo=19261].)

The writeframesraw() and writeframes() methods now accept any bytes-like object. (Contributed by Serhiy Storchaka in bpo-8311 [https://bugs.python.org/issue?@action=redirect&bpo=8311].)

sys

New function sys.getallocatedblocks() returns the current number of blocks allocated by the interpreter. (In CPython with the default --with-pymalloc setting, this is allocations made through the PyObject_Malloc() API.) This can be useful for tracking memory leaks, especially if automated via a test suite. (Contributed by Antoine Pitrou in bpo-13390 [https://bugs.python.org/issue?@action=redirect&bpo=13390].)

When the Python interpreter starts in interactive mode, it checks for an __interactivehook__ attribute on the sys module. If the attribute exists, its value is called with no arguments just before interactive mode is started. The check is made after the PYTHONSTARTUP file is read, so it can be set there. The site module sets it to a function that enables tab completion and history saving (in ~/.python-history) if the platform supports readline. If you do not want this (new) behavior, you can override it in PYTHONSTARTUP, sitecustomize, or usercustomize by deleting this attribute from sys (or setting it to some other callable). (Contributed by Éric Araujo and Antoine Pitrou in bpo-5845 [https://bugs.python.org/issue?@action=redirect&bpo=5845].)

tarfile

The tarfile module now supports a simple 명령 줄 인터페이스 when called as a script directly or via -m. This can be used to create and extract tarfile archives. (Contributed by Berker Peksag in bpo-13477 [https://bugs.python.org/issue?@action=redirect&bpo=13477].)

textwrap

The TextWrapper class has two new attributes/constructor arguments: max_lines, which limits the number of lines in the output, and placeholder, which is a string that will appear at the end of the output if it has been truncated because of max_lines. Building on these capabilities, a new convenience function shorten() collapses all of the whitespace in the input to single spaces and produces a single line of a given width that ends with the placeholder (by default, [...]). (Contributed by Antoine Pitrou and Serhiy Storchaka in bpo-18585 [https://bugs.python.org/issue?@action=redirect&bpo=18585] and bpo-18725 [https://bugs.python.org/issue?@action=redirect&bpo=18725].)

threading

The Thread object representing the main thread can be obtained from the new main_thread() function. In normal conditions this will be the thread from which the Python interpreter was started. (Contributed by Andrew Svetlov in bpo-18882 [https://bugs.python.org/issue?@action=redirect&bpo=18882].)

traceback

A new traceback.clear_frames() function takes a traceback object and clears the local variables in all of the frames it references, reducing the amount of memory consumed. (Contributed by Andrew Kuchling in bpo-1565525 [https://bugs.python.org/issue?@action=redirect&bpo=1565525].)

types

A new DynamicClassAttribute() descriptor provides a way to define an attribute that acts normally when looked up through an instance object, but which is routed to the class __getattr__ when looked up through the class. This allows one to have properties active on a class, and have virtual attributes on the class with the same name (see Enum for an example). (Contributed by Ethan Furman in bpo-19030 [https://bugs.python.org/issue?@action=redirect&bpo=19030].)

urllib

urllib.request now supports data: URLs via the DataHandler class. (Contributed by Mathias Panzenböck in bpo-16423 [https://bugs.python.org/issue?@action=redirect&bpo=16423].)

The http method that will be used by a Request class can now be specified by setting a method class attribute on the subclass. (Contributed by Jason R Coombs in bpo-18978 [https://bugs.python.org/issue?@action=redirect&bpo=18978].)

Request objects are now reusable: if the full_url or data attributes are modified, all relevant internal properties are updated. This means, for example, that it is now possible to use the same Request object in more than one OpenerDirector.open() call with different data arguments, or to modify a Request‘s url rather than recomputing it from scratch. There is also a new remove_header() method that can be used to remove headers from a Request. (Contributed by Alexey Kachayev in bpo-16464 [https://bugs.python.org/issue?@action=redirect&bpo=16464], Daniel Wozniak in bpo-17485 [https://bugs.python.org/issue?@action=redirect&bpo=17485], and Damien Brecht and Senthil Kumaran in bpo-17272 [https://bugs.python.org/issue?@action=redirect&bpo=17272].)

HTTPError objects now have a headers attribute that provides access to the HTTP response headers associated with the error. (Contributed by Berker Peksag in bpo-15701 [https://bugs.python.org/issue?@action=redirect&bpo=15701].)

unittest

The TestCase class has a new method, subTest(), that produces a context manager whose with block becomes a “sub-test”. This context manager allows a test method to dynamically generate subtests by, say, calling the subTest context manager inside a loop. A single test method can thereby produce an indefinite number of separately identified and separately counted tests, all of which will run even if one or more of them fail. For example:

class NumbersTest(unittest.TestCase):
    def test_even(self):
        for i in range(6):
            with self.subTest(i=i):
                self.assertEqual(i % 2, 0)

will result in six subtests, each identified in the unittest verbose output with a label consisting of the variable name i and a particular value for that variable (i=0, i=1, etc). See 부분 테스트(subtest)를 사용하여 테스트 반복 구별 짓기 for the full version of this example. (Contributed by Antoine Pitrou in bpo-16997 [https://bugs.python.org/issue?@action=redirect&bpo=16997].)

unittest.main() now accepts an iterable of test names for defaultTest, where previously it only accepted a single test name as a string. (Contributed by Jyrki Pulliainen in bpo-15132 [https://bugs.python.org/issue?@action=redirect&bpo=15132].)

If SkipTest is raised during test discovery (that is, at the module level in the test file), it is now reported as a skip instead of an error. (Contributed by Zach Ware in bpo-16935 [https://bugs.python.org/issue?@action=redirect&bpo=16935].)

discover() now sorts the discovered files to provide consistent test ordering. (Contributed by Martin Melin and Jeff Ramnani in bpo-16709 [https://bugs.python.org/issue?@action=redirect&bpo=16709].)

TestSuite now drops references to tests as soon as the test has been run, if the test is successful. On Python interpreters that do garbage collection, this allows the tests to be garbage collected if nothing else is holding a reference to the test. It is possible to override this behavior by creating a TestSuite subclass that defines a custom _removeTestAtIndex method. (Contributed by Tom Wardill, Matt McClure, and Andrew Svetlov in bpo-11798 [https://bugs.python.org/issue?@action=redirect&bpo=11798].)

A new test assertion context-manager, assertLogs(), will ensure that a given block of code emits a log message using the logging module. By default the message can come from any logger and have a priority of INFO or higher, but both the logger name and an alternative minimum logging level may be specified. The object returned by the context manager can be queried for the LogRecords and/or formatted messages that were logged. (Contributed by Antoine Pitrou in bpo-18937 [https://bugs.python.org/issue?@action=redirect&bpo=18937].)

Test discovery now works with namespace packages (Contributed by Claudiu Popa in bpo-17457 [https://bugs.python.org/issue?@action=redirect&bpo=17457].)

unittest.mock objects now inspect their specification signatures when matching calls, which means an argument can now be matched by either position or name, instead of only by position. (Contributed by Antoine Pitrou in bpo-17015 [https://bugs.python.org/issue?@action=redirect&bpo=17015].)

mock_open() objects now have readline and readlines methods. (Contributed by Toshio Kuratomi in bpo-17467 [https://bugs.python.org/issue?@action=redirect&bpo=17467].)

venv

venv now includes activation scripts for the csh and fish shells. (Contributed by Andrew Svetlov in bpo-15417 [https://bugs.python.org/issue?@action=redirect&bpo=15417].)

EnvBuilder and the create() convenience function take a new keyword argument with_pip, which defaults to False, that controls whether or not EnvBuilder ensures that pip is installed in the virtual environment. (Contributed by Nick Coghlan in bpo-19552 [https://bugs.python.org/issue?@action=redirect&bpo=19552] as part of the PEP 453 [https://peps.python.org/pep-0453/] implementation.)

wave

The getparams() method now returns a namedtuple rather than a plain tuple. (Contributed by Claudiu Popa in bpo-17487 [https://bugs.python.org/issue?@action=redirect&bpo=17487].)

wave.open() now supports the context management protocol. (Contributed by Claudiu Popa in bpo-17616 [https://bugs.python.org/issue?@action=redirect&bpo=17616].)

wave can now write output to unseekable files. (Contributed by David Jones, Guilherme Polo, and Serhiy Storchaka in bpo-5202 [https://bugs.python.org/issue?@action=redirect&bpo=5202].)

The writeframesraw() and writeframes() methods now accept any bytes-like object. (Contributed by Serhiy Storchaka in bpo-8311 [https://bugs.python.org/issue?@action=redirect&bpo=8311].)

weakref

New WeakMethod class simulates weak references to bound methods. (Contributed by Antoine Pitrou in bpo-14631 [https://bugs.python.org/issue?@action=redirect&bpo=14631].)

New finalize class makes it possible to register a callback to be invoked when an object is garbage collected, without needing to carefully manage the lifecycle of the weak reference itself. (Contributed by Richard Oudkerk in bpo-15528 [https://bugs.python.org/issue?@action=redirect&bpo=15528].)

The callback, if any, associated with a ref is now exposed via the __callback__ attribute. (Contributed by Mark Dickinson in bpo-17643 [https://bugs.python.org/issue?@action=redirect&bpo=17643].)

xml.etree

A new parser, XMLPullParser, allows a non-blocking applications to parse XML documents. An example can be seen at 비 블로킹 구문 분석을 위한 풀(pull) API. (Contributed by Antoine Pitrou in bpo-17741 [https://bugs.python.org/issue?@action=redirect&bpo=17741].)

The xml.etree.ElementTree tostring() and tostringlist() functions, and the ElementTree write() method, now have a short_empty_elements keyword-only parameter providing control over whether elements with no content are written in abbreviated (<tag />) or expanded (<tag></tag>) form. (Contributed by Ariel Poliak and Serhiy Storchaka in bpo-14377 [https://bugs.python.org/issue?@action=redirect&bpo=14377].)

zipfile

The writepy() method of the PyZipFile class has a new filterfunc option that can be used to control which directories and files are added to the archive. For example, this could be used to exclude test files from the archive. (Contributed by Christian Tismer in bpo-19274 [https://bugs.python.org/issue?@action=redirect&bpo=19274].)

The allowZip64 parameter to ZipFile and PyZipfile is now True by default. (Contributed by William Mallard in bpo-17201 [https://bugs.python.org/issue?@action=redirect&bpo=17201].)

CPython Implementation Changes

PEP 445: Customization of CPython Memory Allocators

PEP 445 [https://peps.python.org/pep-0445/] adds new C level interfaces to customize memory allocation in the CPython interpreter.

더 보기

PEP 445 [https://peps.python.org/pep-0445/] – Add new APIs to customize Python memory allocators

PEP written and implemented by Victor Stinner.

PEP 442: Safe Object Finalization

PEP 442 [https://peps.python.org/pep-0442/] removes the current limitations and quirks of object finalization in CPython. With it, objects with __del__() methods, as well as generators with finally clauses, can be finalized when they are part of a reference cycle.

As part of this change, module globals are no longer forcibly set to None during interpreter shutdown in most cases, instead relying on the normal operation of the cyclic garbage collector. This avoids a whole class of interpreter-shutdown-time errors, usually involving __del__ methods, that have plagued Python since the cyclic GC was first introduced.

더 보기

PEP 442 [https://peps.python.org/pep-0442/] – Safe object finalization

PEP written and implemented by Antoine Pitrou.

PEP 456: Secure and Interchangeable Hash Algorithm

PEP 456 [https://peps.python.org/pep-0456/] follows up on earlier security fix work done on Python’s hash algorithm to address certain DOS attacks to which public facing APIs backed by dictionary lookups may be subject. (See bpo-14621 [https://bugs.python.org/issue?@action=redirect&bpo=14621] for the start of the current round of improvements.) The PEP unifies CPython’s hash code to make it easier for a packager to substitute a different hash algorithm, and switches Python’s default implementation to a SipHash implementation on platforms that have a 64 bit data type. Any performance differences in comparison with the older FNV algorithm are trivial.

The PEP adds additional fields to the sys.hash_info named tuple to describe the hash algorithm in use by the currently executing binary. Otherwise, the PEP does not alter any existing CPython APIs.

PEP 436: Argument Clinic

“Argument Clinic” (PEP 436 [https://peps.python.org/pep-0436/]) is now part of the CPython build process and can be used to simplify the process of defining and maintaining accurate signatures for builtins and standard library extension modules implemented in C.

Some standard library extension modules have been converted to use Argument Clinic in Python 3.4, and pydoc and inspect have been updated accordingly.

It is expected that signature metadata for programmatic introspection will be added to additional callables implemented in C as part of Python 3.4 maintenance releases.

참고

The Argument Clinic PEP is not fully up to date with the state of the implementation. This has been deemed acceptable by the release manager and core development team in this case, as Argument Clinic will not be made available as a public API for third party use in Python 3.4.

더 보기

PEP 436 [https://peps.python.org/pep-0436/] – The Argument Clinic DSL

PEP written and implemented by Larry Hastings.

Other Build and C API Changes

The new PyType_GetSlot() function has been added to the stable ABI, allowing retrieval of function pointers from named type slots when using the limited API. (Contributed by Martin von Löwis in bpo-17162 [https://bugs.python.org/issue?@action=redirect&bpo=17162].)

The new Py_SetStandardStreamEncoding() pre-initialization API allows applications embedding the CPython interpreter to reliably force a particular encoding and error handler for the standard streams. (Contributed by Bastien Montagne and Nick Coghlan in bpo-16129 [https://bugs.python.org/issue?@action=redirect&bpo=16129].)

Most Python C APIs that don’t mutate string arguments are now correctly marked as accepting const char * rather than char *. (Contributed by Serhiy Storchaka in bpo-1772673 [https://bugs.python.org/issue?@action=redirect&bpo=1772673].)

A new shell version of python-config can be used even when a python interpreter is not available (for example, in cross compilation scenarios).

PyUnicode_FromFormat() now supports width and precision specifications for %s, %A, %U, %V, %S, and %R. (Contributed by Ysj Ray and Victor Stinner in bpo-7330 [https://bugs.python.org/issue?@action=redirect&bpo=7330].)

New function PyStructSequence_InitType2() supplements the existing PyStructSequence_InitType() function. The difference is that it returns 0 on success and -1 on failure.

The CPython source can now be compiled using the address sanity checking features of recent versions of GCC and clang: the false alarms in the small object allocator have been silenced. (Contributed by Dhiru Kholia in bpo-18596 [https://bugs.python.org/issue?@action=redirect&bpo=18596].)

The Windows build now uses Address Space Layout Randomization [https://en.wikipedia.org/wiki/Address_space_layout_randomization] and Data Execution Prevention [https://en.wikipedia.org/wiki/Data_Execution_Prevention]. (Contributed by Christian Heimes in bpo-16632 [https://bugs.python.org/issue?@action=redirect&bpo=16632].)

New function PyObject_LengthHint() is the C API equivalent of operator.length_hint(). (Contributed by Armin Ronacher in bpo-16148 [https://bugs.python.org/issue?@action=redirect&bpo=16148].)

Other Improvements

The python command has a new option, -I, which causes it to run in “isolated mode”, which means that sys.path contains neither the script’s directory nor the user’s site-packages directory, and all PYTHON* environment variables are ignored (it implies both -s and -E). Other restrictions may also be applied in the future, with the goal being to isolate the execution of a script from the user’s environment. This is appropriate, for example, when Python is used to run a system script. On most POSIX systems it can and should be used in the #! line of system scripts. (Contributed by Christian Heimes in bpo-16499 [https://bugs.python.org/issue?@action=redirect&bpo=16499].)

Tab-completion is now enabled by default in the interactive interpreter on systems that support readline. History is also enabled by default, and is written to (and read from) the file ~/.python-history. (Contributed by Antoine Pitrou and Éric Araujo in bpo-5845 [https://bugs.python.org/issue?@action=redirect&bpo=5845].)

Invoking the Python interpreter with --version now outputs the version to standard output instead of standard error (bpo-18338 [https://bugs.python.org/issue?@action=redirect&bpo=18338]). Similar changes were made to argparse (bpo-18920 [https://bugs.python.org/issue?@action=redirect&bpo=18920]) and other modules that have script-like invocation capabilities (bpo-18922 [https://bugs.python.org/issue?@action=redirect&bpo=18922]).

The CPython Windows installer now adds .py to the PATHEXT variable when extensions are registered, allowing users to run a python script at the windows command prompt by just typing its name without the .py extension. (Contributed by Paul Moore in bpo-18569 [https://bugs.python.org/issue?@action=redirect&bpo=18569].)

A new make target coverage-report [https://devguide.python.org/coverage/#measuring-coverage-of-c-code-with-gcov-and-lcov] will build python, run the test suite, and generate an HTML coverage report for the C codebase using gcov and lcov [https://github.com/linux-test-project/lcov].

The -R option to the python regression test suite now also checks for memory allocation leaks, using sys.getallocatedblocks(). (Contributed by Antoine Pitrou in bpo-13390 [https://bugs.python.org/issue?@action=redirect&bpo=13390].)

python -m now works with namespace packages.

The stat module is now implemented in C, which means it gets the values for its constants from the C header files, instead of having the values hard-coded in the python module as was previously the case.

Loading multiple python modules from a single OS module (.so, .dll) now works correctly (previously it silently returned the first python module in the file). (Contributed by Václav Šmilauer in bpo-16421 [https://bugs.python.org/issue?@action=redirect&bpo=16421].)

A new opcode, LOAD_CLASSDEREF, has been added to fix a bug in the loading of free variables in class bodies that could be triggered by certain uses of __prepare__. (Contributed by Benjamin Peterson in bpo-17853 [https://bugs.python.org/issue?@action=redirect&bpo=17853].)

A number of MemoryError-related crashes were identified and fixed by Victor Stinner using his PEP 445 [https://peps.python.org/pep-0445/]-based pyfailmalloc tool (bpo-18408 [https://bugs.python.org/issue?@action=redirect&bpo=18408], bpo-18520 [https://bugs.python.org/issue?@action=redirect&bpo=18520]).

The pyvenv command now accepts a --copies option to use copies rather than symlinks even on systems where symlinks are the default. (Contributed by Vinay Sajip in bpo-18807 [https://bugs.python.org/issue?@action=redirect&bpo=18807].)

The pyvenv command also accepts a --without-pip option to suppress the otherwise-automatic bootstrapping of pip into the virtual environment. (Contributed by Nick Coghlan in bpo-19552 [https://bugs.python.org/issue?@action=redirect&bpo=19552] as part of the PEP 453 [https://peps.python.org/pep-0453/] implementation.)

The encoding name is now optional in the value set for the PYTHONIOENCODING environment variable. This makes it possible to set just the error handler, without changing the default encoding. (Contributed by Serhiy Storchaka in bpo-18818 [https://bugs.python.org/issue?@action=redirect&bpo=18818].)

The bz2, lzma, and gzip module open functions now support x (exclusive creation) mode. (Contributed by Tim Heaney and Vajrasky Kok in bpo-19201 [https://bugs.python.org/issue?@action=redirect&bpo=19201], bpo-19222 [https://bugs.python.org/issue?@action=redirect&bpo=19222], and bpo-19223 [https://bugs.python.org/issue?@action=redirect&bpo=19223].)

Significant Optimizations

The UTF-32 decoder is now 3x to 4x faster. (Contributed by Serhiy Storchaka in bpo-14625 [https://bugs.python.org/issue?@action=redirect&bpo=14625].)

The cost of hash collisions for sets is now reduced. Each hash table probe now checks a series of consecutive, adjacent key/hash pairs before continuing to make random probes through the hash table. This exploits cache locality to make collision resolution less expensive. The collision resolution scheme can be described as a hybrid of linear probing and open addressing. The number of additional linear probes defaults to nine. This can be changed at compile-time by defining LINEAR_PROBES to be any value. Set LINEAR_PROBES=0 to turn-off linear probing entirely. (Contributed by Raymond Hettinger in bpo-18771 [https://bugs.python.org/issue?@action=redirect&bpo=18771].)

The interpreter starts about 30% faster. A couple of measures lead to the speedup. The interpreter loads fewer modules on startup, e.g. the re, collections and locale modules and their dependencies are no longer imported by default. The marshal module has been improved to load compiled Python code faster. (Contributed by Antoine Pitrou, Christian Heimes and Victor Stinner in bpo-19219 [https://bugs.python.org/issue?@action=redirect&bpo=19219], bpo-19218 [https://bugs.python.org/issue?@action=redirect&bpo=19218], bpo-19209 [https://bugs.python.org/issue?@action=redirect&bpo=19209], bpo-19205 [https://bugs.python.org/issue?@action=redirect&bpo=19205] and bpo-9548 [https://bugs.python.org/issue?@action=redirect&bpo=9548].)

bz2.BZ2File is now as fast or faster than the Python2 version for most cases. lzma.LZMAFile has also been optimized. (Contributed by Serhiy Storchaka and Nadeem Vawda in bpo-16034 [https://bugs.python.org/issue?@action=redirect&bpo=16034].)

random.getrandbits() is 20%-40% faster for small integers (the most common use case). (Contributed by Serhiy Storchaka in bpo-16674 [https://bugs.python.org/issue?@action=redirect&bpo=16674].)

By taking advantage of the new storage format for strings, pickling of strings is now significantly faster. (Contributed by Victor Stinner and Antoine Pitrou in bpo-15596 [https://bugs.python.org/issue?@action=redirect&bpo=15596].)

A performance issue in io.FileIO.readall() has been solved. This particularly affects Windows, and significantly speeds up the case of piping significant amounts of data through subprocess. (Contributed by Richard Oudkerk in bpo-15758 [https://bugs.python.org/issue?@action=redirect&bpo=15758].)

html.escape() is now 10x faster. (Contributed by Matt Bryant in bpo-18020 [https://bugs.python.org/issue?@action=redirect&bpo=18020].)

On Windows, the native VirtualAlloc is now used instead of the CRT malloc in obmalloc. Artificial benchmarks show about a 3% memory savings.

os.urandom() now uses a lazily opened persistent file descriptor so as to avoid using many file descriptors when run in parallel from multiple threads. (Contributed by Antoine Pitrou in bpo-18756 [https://bugs.python.org/issue?@action=redirect&bpo=18756].)

Deprecated

This section covers various APIs and other features that have been deprecated in Python 3.4, and will be removed in Python 3.5 or later. In most (but not all) cases, using the deprecated APIs will produce a DeprecationWarning when the interpreter is run with deprecation warnings enabled (for example, by using -Wd).

Deprecations in the Python API

As mentioned in PEP 451: A ModuleSpec Type for the Import System, a number of importlib methods and functions are deprecated: importlib.find_loader() is replaced by importlib.util.find_spec(); importlib.machinery.PathFinder.find_module() is replaced by importlib.machinery.PathFinder.find_spec(); importlib.abc.MetaPathFinder.find_module() is replaced by importlib.abc.MetaPathFinder.find_spec(); importlib.abc.PathEntryFinder.find_loader() and find_module() are replaced by importlib.abc.PathEntryFinder.find_spec(); all of the xxxLoader ABC load_module methods (importlib.abc.Loader.load_module(), importlib.abc.InspectLoader.load_module(), importlib.abc.FileLoader.load_module(), importlib.abc.SourceLoader.load_module()) should no longer be implemented, instead loaders should implement an exec_module method (importlib.abc.Loader.exec_module(), importlib.abc.InspectLoader.exec_module() importlib.abc.SourceLoader.exec_module()) and let the import system take care of the rest; and importlib.abc.Loader.module_repr(), importlib.util.module_for_loader(), importlib.util.set_loader(), and importlib.util.set_package() are no longer needed because their functions are now handled automatically by the import system.

The imp module is pending deprecation. To keep compatibility with Python 2/3 code bases, the module’s removal is currently not scheduled.

The formatter module is pending deprecation and is slated for removal in Python 3.6.

MD5 as the default digestmod for the hmac.new() function is deprecated. Python 3.6 will require an explicit digest name or constructor as digestmod argument.

The internal Netrc class in the ftplib module has been documented as deprecated in its docstring for quite some time. It now emits a DeprecationWarning and will be removed completely in Python 3.5.

The undocumented endtime argument to subprocess.Popen.wait() should not have been exposed and is hopefully not in use; it is deprecated and will mostly likely be removed in Python 3.5.

The strict argument of HTMLParser is deprecated.

The plistlib readPlist(), writePlist(), readPlistFromBytes(), and writePlistToBytes() functions are deprecated in favor of the corresponding new functions load(), dump(), loads(), and dumps(). Data() is deprecated in favor of just using the bytes constructor.

The sysconfig key SO is deprecated, it has been replaced by EXT_SUFFIX.

The U mode accepted by various open functions is deprecated. In Python3 it does not do anything useful, and should be replaced by appropriate uses of io.TextIOWrapper (if needed) and its newline argument.

The parser argument of xml.etree.ElementTree.iterparse() has been deprecated, as has the html argument of XMLParser(). To prepare for the removal of the latter, all arguments to XMLParser should be passed by keyword.

Deprecated Features

Running IDLE with the -n flag (no subprocess) is deprecated. However, the feature will not be removed until bpo-18823 [https://bugs.python.org/issue?@action=redirect&bpo=18823] is resolved.

The site module adding a “site-python” directory to sys.path, if it exists, is deprecated (bpo-19375 [https://bugs.python.org/issue?@action=redirect&bpo=19375]).

Removed

Operating Systems No Longer Supported

Support for the following operating systems has been removed from the source and build tools:

OS/2 (bpo-16135 [https://bugs.python.org/issue?@action=redirect&bpo=16135]).

Windows 2000 (changeset e52df05b496a).

Windows systems where COMSPEC points to command.com (bpo-14470 [https://bugs.python.org/issue?@action=redirect&bpo=14470]).

VMS (bpo-16136 [https://bugs.python.org/issue?@action=redirect&bpo=16136]).

API and Feature Removals

The following obsolete and previously deprecated APIs and features have been removed:

The unmaintained Misc/TextMate and Misc/vim directories have been removed (see the devguide [https://devguide.python.org] for suggestions on what to use instead).

The SO makefile macro is removed (it was replaced by the SHLIB_SUFFIX and EXT_SUFFIX macros) (bpo-16754 [https://bugs.python.org/issue?@action=redirect&bpo=16754]).

The PyThreadState.tick_counter field has been removed; its value has been meaningless since Python 3.2, when the “new GIL” was introduced (bpo-19199 [https://bugs.python.org/issue?@action=redirect&bpo=19199]).

PyLoader and PyPycLoader have been removed from importlib. (Contributed by Taras Lyapun in bpo-15641 [https://bugs.python.org/issue?@action=redirect&bpo=15641].)

The strict argument to HTTPConnection and HTTPSConnection has been removed. HTTP 0.9-style “Simple Responses” are no longer supported.

The deprecated urllib.request.Request getter and setter methods add_data, has_data, get_data, get_type, get_host, get_selector, set_proxy, get_origin_req_host, and is_unverifiable have been removed (use direct attribute access instead).

Support for loading the deprecated TYPE_INT64 has been removed from marshal. (Contributed by Dan Riti in bpo-15480 [https://bugs.python.org/issue?@action=redirect&bpo=15480].)

inspect.Signature: positional-only parameters are now required to have a valid name.

object.__format__() no longer accepts non-empty format strings, it now raises a TypeError instead. Using a non-empty string has been deprecated since Python 3.2. This change has been made to prevent a situation where previously working (but incorrect) code would start failing if an object gained a __format__ method, which means that your code may now raise a TypeError if you are using an 's' format code with objects that do not have a __format__ method that handles it. See bpo-7994 [https://bugs.python.org/issue?@action=redirect&bpo=7994] for background.

difflib.SequenceMatcher.isbjunk() and difflib.SequenceMatcher.isbpopular() were deprecated in 3.2, and have now been removed: use x in sm.bjunk and x in sm.bpopular, where sm is a SequenceMatcher object (bpo-13248 [https://bugs.python.org/issue?@action=redirect&bpo=13248]).

Code Cleanups

The unused and undocumented internal Scanner class has been removed from the pydoc module.

The private and effectively unused _gestalt module has been removed, along with the private platform functions _mac_ver_lookup, _mac_ver_gstalt, and _bcd2str, which would only have ever been called on badly broken OSX systems (see bpo-18393 [https://bugs.python.org/issue?@action=redirect&bpo=18393]).

The hardcoded copies of certain stat constants that were included in the tarfile module namespace have been removed.

Porting to Python 3.4

This section lists previously described changes and other bugfixes that may require changes to your code.

Changes in ‘python’ Command Behavior

In a posix shell, setting the PATH environment variable to an empty value is equivalent to not setting it at all. However, setting PYTHONPATH to an empty value was not equivalent to not setting it at all: setting PYTHONPATH to an empty value was equivalent to setting it to ., which leads to confusion when reasoning by analogy to how PATH works. The behavior now conforms to the posix convention for PATH.

The [X refs, Y blocks] output of a debug (--with-pydebug) build of the CPython interpreter is now off by default. It can be re-enabled using the -X showrefcount option. (Contributed by Ezio Melotti in bpo-17323 [https://bugs.python.org/issue?@action=redirect&bpo=17323].)

The python command and most stdlib scripts (as well as argparse) now output --version information to stdout instead of stderr (for issue list see Other Improvements above).

Changes in the Python API

The ABCs defined in importlib.abc now either raise the appropriate exception or return a default value instead of raising NotImplementedError blindly. This will only affect code calling super() and falling through all the way to the ABCs. For compatibility, catch both NotImplementedError or the appropriate exception as needed.

The module type now initializes the __package__ and __loader__ attributes to None by default. To determine if these attributes were set in a backwards-compatible fashion, use e.g. getattr(module, '__loader__', None) is not None. (bpo-17115 [https://bugs.python.org/issue?@action=redirect&bpo=17115].)

importlib.util.module_for_loader() now sets __loader__ and __package__ unconditionally to properly support reloading. If this is not desired then you will need to set these attributes manually. You can use importlib.util.module_to_load() for module management.

Import now resets relevant attributes (e.g. __name__, __loader__, __package__, __file__, __cached__) unconditionally when reloading. Note that this restores a pre-3.3 behavior in that it means a module is re-found when re-loaded (bpo-19413 [https://bugs.python.org/issue?@action=redirect&bpo=19413]).

Frozen packages no longer set __path__ to a list containing the package name, they now set it to an empty list. The previous behavior could cause the import system to do the wrong thing on submodule imports if there was also a directory with the same name as the frozen package. The correct way to determine if a module is a package or not is to use hasattr(module, '__path__') (bpo-18065 [https://bugs.python.org/issue?@action=redirect&bpo=18065]).

Frozen modules no longer define a __file__ attribute. It’s semantically incorrect for frozen modules to set the attribute as they are not loaded from any explicit location. If you must know that a module comes from frozen code then you can see if the module’s __spec__.location is set to 'frozen', check if the loader is a subclass of importlib.machinery.FrozenImporter, or if Python 2 compatibility is necessary you can use imp.is_frozen().

py_compile.compile() now raises FileExistsError if the file path it would write to is a symlink or a non-regular file. This is to act as a warning that import will overwrite those files with a regular file regardless of what type of file path they were originally.

importlib.abc.SourceLoader.get_source() no longer raises ImportError when the source code being loaded triggers a SyntaxError or UnicodeDecodeError. As ImportError is meant to be raised only when source code cannot be found but it should, it was felt to be over-reaching/overloading of that meaning when the source code is found but improperly structured. If you were catching ImportError before and wish to continue to ignore syntax or decoding issues, catch all three exceptions now.

functools.update_wrapper() and functools.wraps() now correctly set the __wrapped__ attribute to the function being wrapped, even if that function also had its __wrapped__ attribute set. This means __wrapped__ attributes now correctly link a stack of decorated functions rather than every __wrapped__ attribute in the chain referring to the innermost function. Introspection libraries that assumed the previous behaviour was intentional can use inspect.unwrap() to access the first function in the chain that has no __wrapped__ attribute.

inspect.getfullargspec() has been reimplemented on top of inspect.signature() and hence handles a much wider variety of callable objects than it did in the past. It is expected that additional builtin and extension module callables will gain signature metadata over the course of the Python 3.4 series. Code that assumes that inspect.getfullargspec() will fail on non-Python callables may need to be adjusted accordingly.

importlib.machinery.PathFinder now passes on the current working directory to objects in sys.path_hooks for the empty string. This results in sys.path_importer_cache never containing '', thus iterating through sys.path_importer_cache based on sys.path will not find all keys. A module’s __file__ when imported in the current working directory will also now have an absolute path, including when using -m with the interpreter (except for __main__.__file__ when a script has been executed directly using a relative path) (Contributed by Brett Cannon in bpo-18416 [https://bugs.python.org/issue?@action=redirect&bpo=18416]). is specified on the command-line) (bpo-18416 [https://bugs.python.org/issue?@action=redirect&bpo=18416]).

The removal of the strict argument to HTTPConnection and HTTPSConnection changes the meaning of the remaining arguments if you are specifying them positionally rather than by keyword. If you’ve been paying attention to deprecation warnings your code should already be specifying any additional arguments via keywords.

Strings between from __future__ import ... statements now always raise a SyntaxError. Previously if there was no leading docstring, an interstitial string would sometimes be ignored. This brings CPython into compliance with the language spec; Jython and PyPy already were. (bpo-17434 [https://bugs.python.org/issue?@action=redirect&bpo=17434]).

ssl.SSLSocket.getpeercert() and ssl.SSLSocket.do_handshake() now raise an OSError with ENOTCONN when the SSLSocket is not connected, instead of the previous behavior of raising an AttributeError. In addition, getpeercert() will raise a ValueError if the handshake has not yet been done.

base64.b32decode() now raises a binascii.Error when the input string contains non-b32-alphabet characters, instead of a TypeError. This particular TypeError was missed when the other TypeErrors were converted. (Contributed by Serhiy Storchaka in bpo-18011 [https://bugs.python.org/issue?@action=redirect&bpo=18011].) Note: this change was also inadvertently applied in Python 3.3.3.

The file attribute is now automatically closed when the creating cgi.FieldStorage instance is garbage collected. If you were pulling the file object out separately from the cgi.FieldStorage instance and not keeping the instance alive, then you should either store the entire cgi.FieldStorage instance or read the contents of the file before the cgi.FieldStorage instance is garbage collected.

Calling read or write on a closed SSL socket now raises an informative ValueError rather than the previous more mysterious AttributeError (bpo-9177 [https://bugs.python.org/issue?@action=redirect&bpo=9177]).

slice.indices() no longer produces an OverflowError for huge values. As a consequence of this fix, slice.indices() now raises a ValueError if given a negative length; previously it returned nonsense values (bpo-14794 [https://bugs.python.org/issue?@action=redirect&bpo=14794]).

The complex constructor, unlike the cmath functions, was incorrectly accepting float values if an object’s __complex__ special method returned one. This now raises a TypeError. (bpo-16290 [https://bugs.python.org/issue?@action=redirect&bpo=16290].)

The int constructor in 3.2 and 3.3 erroneously accepts float values for the base parameter. It is unlikely anyone was doing this, but if so, it will now raise a TypeError (bpo-16772 [https://bugs.python.org/issue?@action=redirect&bpo=16772]).

Defaults for keyword-only arguments are now evaluated after defaults for regular keyword arguments, instead of before. Hopefully no one wrote any code that depends on the previous buggy behavior (bpo-16967 [https://bugs.python.org/issue?@action=redirect&bpo=16967]).

Stale thread states are now cleared after fork(). This may cause some system resources to be released that previously were incorrectly kept perpetually alive (for example, database connections kept in thread-local storage). (bpo-17094 [https://bugs.python.org/issue?@action=redirect&bpo=17094].)

Parameter names in __annotations__ dicts are now mangled properly, similarly to __kwdefaults__. (Contributed by Yury Selivanov in bpo-20625 [https://bugs.python.org/issue?@action=redirect&bpo=20625].)

hashlib.hash.name now always returns the identifier in lower case. Previously some builtin hashes had uppercase names, but now that it is a formal public interface the naming has been made consistent (bpo-18532 [https://bugs.python.org/issue?@action=redirect&bpo=18532]).

Because unittest.TestSuite now drops references to tests after they are run, test harnesses that reuse a TestSuite to re-run a set of tests may fail. Test suites should not be re-used in this fashion since it means state is retained between test runs, breaking the test isolation that unittest is designed to provide. However, if the lack of isolation is considered acceptable, the old behavior can be restored by creating a TestSuite subclass that defines a _removeTestAtIndex method that does nothing (see TestSuite.__iter__()) (bpo-11798 [https://bugs.python.org/issue?@action=redirect&bpo=11798]).

unittest now uses argparse for command line parsing. There are certain invalid command forms that used to work that are no longer allowed; in theory this should not cause backward compatibility issues since the disallowed command forms didn’t make any sense and are unlikely to be in use.

The re.split(), re.findall(), and re.sub() functions, and the group() and groups() methods of match objects now always return a bytes object when the string to be matched is a bytes-like object. Previously the return type matched the input type, so if your code was depending on the return value being, say, a bytearray, you will need to change your code.

audioop functions now raise an error immediately if passed string input, instead of failing randomly later on (bpo-16685 [https://bugs.python.org/issue?@action=redirect&bpo=16685]).

The new convert_charrefs argument to HTMLParser currently defaults to False for backward compatibility, but will eventually be changed to default to True. It is recommended that you add this keyword, with the appropriate value, to any HTMLParser calls in your code (bpo-13633 [https://bugs.python.org/issue?@action=redirect&bpo=13633]).

Since the digestmod argument to the hmac.new() function will in the future have no default, all calls to hmac.new() should be changed to explicitly specify a digestmod (bpo-17276 [https://bugs.python.org/issue?@action=redirect&bpo=17276]).

Calling sysconfig.get_config_var() with the SO key, or looking SO up in the results of a call to sysconfig.get_config_vars() is deprecated. This key should be replaced by EXT_SUFFIX or SHLIB_SUFFIX, depending on the context (bpo-19555 [https://bugs.python.org/issue?@action=redirect&bpo=19555]).

Any calls to open functions that specify U should be modified. U is ineffective in Python3 and will eventually raise an error if used. Depending on the function, the equivalent of its old Python2 behavior can be achieved using either a newline argument, or if necessary by wrapping the stream in TextIOWrapper to use its newline argument (bpo-15204 [https://bugs.python.org/issue?@action=redirect&bpo=15204]).

If you use pyvenv in a script and desire that pip not be installed, you must add --without-pip to your command invocation.

The default behavior of json.dump() and json.dumps() when an indent is specified has changed: it no longer produces trailing spaces after the item separating commas at the ends of lines. This will matter only if you have tests that are doing white-space-sensitive comparisons of such output (bpo-16333 [https://bugs.python.org/issue?@action=redirect&bpo=16333]).

doctest now looks for doctests in extension module __doc__ strings, so if your doctest test discovery includes extension modules that have things that look like doctests in them you may see test failures you’ve never seen before when running your tests (bpo-3158 [https://bugs.python.org/issue?@action=redirect&bpo=3158]).

The collections.abc module has been slightly refactored as part of the Python startup improvements. As a consequence of this, it is no longer the case that importing collections automatically imports collections.abc. If your program depended on the (undocumented) implicit import, you will need to add an explicit import collections.abc (bpo-20784 [https://bugs.python.org/issue?@action=redirect&bpo=20784]).

Changes in the C API

PyEval_EvalFrameEx(), PyObject_Repr(), and PyObject_Str(), along with some other internal C APIs, now include a debugging assertion that ensures they are not used in situations where they may silently discard a currently active exception. In cases where discarding the active exception is expected and desired (for example, because it has already been saved locally with PyErr_Fetch() or is being deliberately replaced with a different exception), an explicit PyErr_Clear() call will be needed to avoid triggering the assertion when invoking these operations (directly or indirectly) and running against a version of Python that is compiled with assertions enabled.

PyErr_SetImportError() now sets TypeError when its msg argument is not set. Previously only NULL was returned with no exception set.

The result of the PyOS_ReadlineFunctionPointer callback must now be a string allocated by PyMem_RawMalloc() or PyMem_RawRealloc(), or NULL if an error occurred, instead of a string allocated by PyMem_Malloc() or PyMem_Realloc() (bpo-16742 [https://bugs.python.org/issue?@action=redirect&bpo=16742])

PyThread_set_key_value() now always set the value. In Python 3.3, the function did nothing if the key already exists (if the current value is a non-NULL pointer).

The f_tstate (thread state) field of the PyFrameObject structure has been removed to fix a bug: see bpo-14432 [https://bugs.python.org/issue?@action=redirect&bpo=14432] for the rationale.

Changed in 3.4.3

PEP 476: Enabling certificate verification by default for stdlib http clients

http.client and modules which use it, such as urllib.request and xmlrpc.client, will now verify that the server presents a certificate which is signed by a CA in the platform trust store and whose hostname matches the hostname being requested by default, significantly improving security for many applications.

For applications which require the old previous behavior, they can pass an alternate context:

import urllib.request
import ssl

# This disables all verification
context = ssl._create_unverified_context()

# This allows using a specific certificate for the host, which doesn't need
# to be in the trust store
context = ssl.create_default_context(cafile="/path/to/file.crt")

urllib.request.urlopen("https://invalid-cert", context=context)

What’s New In Python 3.3

This article explains the new features in Python 3.3, compared to 3.2. Python 3.3 was released on September 29, 2012. For full details, see the changelog [https://docs.python.org/3.3/whatsnew/changelog.html].

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PEP 398 [https://peps.python.org/pep-0398/] - Python 3.3 Release Schedule

Summary – Release highlights

New syntax features:

New yield from expression for generator delegation.

The u'unicode' syntax is accepted again for str objects.

New library modules:

faulthandler (helps debugging low-level crashes)

ipaddress (high-level objects representing IP addresses and masks)

lzma (compress data using the XZ / LZMA algorithm)

unittest.mock (replace parts of your system under test with mock objects)

venv (Python virtual environments, as in the popular virtualenv package)

New built-in features:

Reworked I/O exception hierarchy.

Implementation improvements:

Rewritten import machinery based on importlib.

More compact unicode strings.

More compact attribute dictionaries.

Significantly Improved Library Modules:

C Accelerator for the decimal module.

Better unicode handling in the email module (provisional).

Security improvements:

Hash randomization is switched on by default.

Please read on for a comprehensive list of user-facing changes.

PEP 405: Virtual Environments

Virtual environments help create separate Python setups while sharing a system-wide base install, for ease of maintenance. Virtual environments have their own set of private site packages (i.e. locally installed libraries), and are optionally segregated from the system-wide site packages. Their concept and implementation are inspired by the popular virtualenv third-party package, but benefit from tighter integration with the interpreter core.

This PEP adds the venv module for programmatic access, and the pyvenv script for command-line access and administration. The Python interpreter checks for a pyvenv.cfg, file whose existence signals the base of a virtual environment’s directory tree.

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PEP 405 [https://peps.python.org/pep-0405/] - Python Virtual Environments

PEP written by Carl Meyer; implementation by Carl Meyer and Vinay Sajip

PEP 420: Implicit Namespace Packages

Native support for package directories that don’t require __init__.py marker files and can automatically span multiple path segments (inspired by various third party approaches to namespace packages, as described in PEP 420 [https://peps.python.org/pep-0420/])

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PEP 420 [https://peps.python.org/pep-0420/] - Implicit Namespace Packages

PEP written by Eric V. Smith; implementation by Eric V. Smith and Barry Warsaw

PEP 3118: New memoryview implementation and buffer protocol documentation

The implementation of PEP 3118 [https://peps.python.org/pep-3118/] has been significantly improved.

The new memoryview implementation comprehensively fixes all ownership and lifetime issues of dynamically allocated fields in the Py_buffer struct that led to multiple crash reports. Additionally, several functions that crashed or returned incorrect results for non-contiguous or multi-dimensional input have been fixed.

The memoryview object now has a PEP-3118 compliant getbufferproc() that checks the consumer’s request type. Many new features have been added, most of them work in full generality for non-contiguous arrays and arrays with suboffsets.

The documentation has been updated, clearly spelling out responsibilities for both exporters and consumers. Buffer request flags are grouped into basic and compound flags. The memory layout of non-contiguous and multi-dimensional NumPy-style arrays is explained.

Features

All native single character format specifiers in struct module syntax (optionally prefixed with ‘@’) are now supported.

With some restrictions, the cast() method allows changing of format and shape of C-contiguous arrays.

Multi-dimensional list representations are supported for any array type.

Multi-dimensional comparisons are supported for any array type.

One-dimensional memoryviews of hashable (read-only) types with formats B, b or c are now hashable. (Contributed by Antoine Pitrou in bpo-13411 [https://bugs.python.org/issue?@action=redirect&bpo=13411].)

Arbitrary slicing of any 1-D arrays type is supported. For example, it is now possible to reverse a memoryview in O(1) by using a negative step.

API changes

The maximum number of dimensions is officially limited to 64.

The representation of empty shape, strides and suboffsets is now an empty tuple instead of None.

Accessing a memoryview element with format ‘B’ (unsigned bytes) now returns an integer (in accordance with the struct module syntax). For returning a bytes object the view must be cast to ‘c’ first.

memoryview comparisons now use the logical structure of the operands and compare all array elements by value. All format strings in struct module syntax are supported. Views with unrecognised format strings are still permitted, but will always compare as unequal, regardless of view contents.

For further changes see Build and C API Changes and Porting C code.

(Contributed by Stefan Krah in bpo-10181 [https://bugs.python.org/issue?@action=redirect&bpo=10181].)

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PEP 3118 [https://peps.python.org/pep-3118/] - Revising the Buffer Protocol

PEP 393: Flexible String Representation

The Unicode string type is changed to support multiple internal representations, depending on the character with the largest Unicode ordinal (1, 2, or 4 bytes) in the represented string. This allows a space-efficient representation in common cases, but gives access to full UCS-4 on all systems. For compatibility with existing APIs, several representations may exist in parallel; over time, this compatibility should be phased out.

On the Python side, there should be no downside to this change.

On the C API side, PEP 393 [https://peps.python.org/pep-0393/] is fully backward compatible. The legacy API should remain available at least five years. Applications using the legacy API will not fully benefit of the memory reduction, or - worse - may use a bit more memory, because Python may have to maintain two versions of each string (in the legacy format and in the new efficient storage).

Functionality

Changes introduced by PEP 393 [https://peps.python.org/pep-0393/] are the following:

Python now always supports the full range of Unicode code points, including non-BMP ones (i.e. from U+0000 to U+10FFFF). The distinction between narrow and wide builds no longer exists and Python now behaves like a wide build, even under Windows.

With the death of narrow builds, the problems specific to narrow builds have also been fixed, for example:

len() now always returns 1 for non-BMP characters, so len('\U0010FFFF') == 1;

surrogate pairs are not recombined in string literals, so '\uDBFF\uDFFF' != '\U0010FFFF';

indexing or slicing non-BMP characters returns the expected value, so '\U0010FFFF'[0] now returns '\U0010FFFF' and not '\uDBFF';

all other functions in the standard library now correctly handle non-BMP code points.

The value of sys.maxunicode is now always 1114111 (0x10FFFF in hexadecimal). The PyUnicode_GetMax() function still returns either 0xFFFF or 0x10FFFF for backward compatibility, and it should not be used with the new Unicode API (see bpo-13054 [https://bugs.python.org/issue?@action=redirect&bpo=13054]).

The ./configure flag --with-wide-unicode has been removed.

Performance and resource usage

The storage of Unicode strings now depends on the highest code point in the string:

pure ASCII and Latin1 strings (U+0000-U+00FF) use 1 byte per code point;

BMP strings (U+0000-U+FFFF) use 2 bytes per code point;

non-BMP strings (U+10000-U+10FFFF) use 4 bytes per code point.

The net effect is that for most applications, memory usage of string storage should decrease significantly - especially compared to former wide unicode builds - as, in many cases, strings will be pure ASCII even in international contexts (because many strings store non-human language data, such as XML fragments, HTTP headers, JSON-encoded data, etc.). We also hope that it will, for the same reasons, increase CPU cache efficiency on non-trivial applications. The memory usage of Python 3.3 is two to three times smaller than Python 3.2, and a little bit better than Python 2.7, on a Django benchmark (see the PEP for details).

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PEP 393 [https://peps.python.org/pep-0393/] - Flexible String Representation

PEP written by Martin von Löwis; implementation by Torsten Becker and Martin von Löwis.

PEP 397: Python Launcher for Windows

The Python 3.3 Windows installer now includes a py launcher application that can be used to launch Python applications in a version independent fashion.

This launcher is invoked implicitly when double-clicking *.py files. If only a single Python version is installed on the system, that version will be used to run the file. If multiple versions are installed, the most recent version is used by default, but this can be overridden by including a Unix-style “shebang line” in the Python script.

The launcher can also be used explicitly from the command line as the py application. Running py follows the same version selection rules as implicitly launching scripts, but a more specific version can be selected by passing appropriate arguments (such as -3 to request Python 3 when Python 2 is also installed, or -2.6 to specifically request an earlier Python version when a more recent version is installed).

In addition to the launcher, the Windows installer now includes an option to add the newly installed Python to the system PATH. (Contributed by Brian Curtin in bpo-3561 [https://bugs.python.org/issue?@action=redirect&bpo=3561].)

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PEP 397 [https://peps.python.org/pep-0397/] - Python Launcher for Windows

PEP written by Mark Hammond and Martin v. Löwis; implementation by Vinay Sajip.

Launcher documentation: 윈도우 용 파이썬 런처

Installer PATH modification: 파이썬 실행 파일 찾기

PEP 3151: Reworking the OS and IO exception hierarchy

The hierarchy of exceptions raised by operating system errors is now both simplified and finer-grained.

You don’t have to worry anymore about choosing the appropriate exception type between OSError, IOError, EnvironmentError, WindowsError, mmap.error, socket.error or select.error. All these exception types are now only one: OSError. The other names are kept as aliases for compatibility reasons.

Also, it is now easier to catch a specific error condition. Instead of inspecting the errno attribute (or args[0]) for a particular constant from the errno module, you can catch the adequate OSError subclass. The available subclasses are the following:

BlockingIOError

ChildProcessError

ConnectionError

FileExistsError

FileNotFoundError

InterruptedError

IsADirectoryError

NotADirectoryError

PermissionError

ProcessLookupError

TimeoutError

And the ConnectionError itself has finer-grained subclasses:

BrokenPipeError

ConnectionAbortedError

ConnectionRefusedError

ConnectionResetError

Thanks to the new exceptions, common usages of the errno can now be avoided. For example, the following code written for Python 3.2:

from errno import ENOENT, EACCES, EPERM

try:
    with open("document.txt") as f:
        content = f.read()
except IOError as err:
    if err.errno == ENOENT:
        print("document.txt file is missing")
    elif err.errno in (EACCES, EPERM):
        print("You are not allowed to read document.txt")
    else:
        raise

can now be written without the errno import and without manual inspection of exception attributes:

try:
    with open("document.txt") as f:
        content = f.read()
except FileNotFoundError:
    print("document.txt file is missing")
except PermissionError:
    print("You are not allowed to read document.txt")

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PEP 3151 [https://peps.python.org/pep-3151/] - Reworking the OS and IO Exception Hierarchy

PEP written and implemented by Antoine Pitrou

PEP 380: Syntax for Delegating to a Subgenerator

PEP 380 adds the yield from expression, allowing a generator to delegate part of its operations to another generator. This allows a section of code containing yield to be factored out and placed in another generator. Additionally, the subgenerator is allowed to return with a value, and the value is made available to the delegating generator.

While designed primarily for use in delegating to a subgenerator, the yield from expression actually allows delegation to arbitrary subiterators.

For simple iterators, yield from iterable is essentially just a shortened form of for item in iterable: yield item:

>>> def g(x):
...     yield from range(x, 0, -1)
...     yield from range(x)
...
>>> list(g(5))
[5, 4, 3, 2, 1, 0, 1, 2, 3, 4]

However, unlike an ordinary loop, yield from allows subgenerators to receive sent and thrown values directly from the calling scope, and return a final value to the outer generator:

>>> def accumulate():
...     tally = 0
...     while 1:
...         next = yield
...         if next is None:
...             return tally
...         tally += next
...
>>> def gather_tallies(tallies):
...     while 1:
...         tally = yield from accumulate()
...         tallies.append(tally)
...
>>> tallies = []
>>> acc = gather_tallies(tallies)
>>> next(acc)  # Ensure the accumulator is ready to accept values
>>> for i in range(4):
...     acc.send(i)
...
>>> acc.send(None)  # Finish the first tally
>>> for i in range(5):
...     acc.send(i)
...
>>> acc.send(None)  # Finish the second tally
>>> tallies
[6, 10]

The main principle driving this change is to allow even generators that are designed to be used with the send and throw methods to be split into multiple subgenerators as easily as a single large function can be split into multiple subfunctions.

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PEP 380 [https://peps.python.org/pep-0380/] - Syntax for Delegating to a Subgenerator

PEP written by Greg Ewing; implementation by Greg Ewing, integrated into 3.3 by Renaud Blanch, Ryan Kelly and Nick Coghlan; documentation by Zbigniew Jędrzejewski-Szmek and Nick Coghlan

PEP 409: Suppressing exception context

PEP 409 introduces new syntax that allows the display of the chained exception context to be disabled. This allows cleaner error messages in applications that convert between exception types:

>>> class D:
...     def __init__(self, extra):
...         self._extra_attributes = extra
...     def __getattr__(self, attr):
...         try:
...             return self._extra_attributes[attr]
...         except KeyError:
...             raise AttributeError(attr) from None
...
>>> D({}).x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 8, in __getattr__
AttributeError: x

Without the from None suffix to suppress the cause, the original exception would be displayed by default:

>>> class C:
...     def __init__(self, extra):
...         self._extra_attributes = extra
...     def __getattr__(self, attr):
...         try:
...             return self._extra_attributes[attr]
...         except KeyError:
...             raise AttributeError(attr)
...
>>> C({}).x
Traceback (most recent call last):
  File "<stdin>", line 6, in __getattr__
KeyError: 'x'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 8, in __getattr__
AttributeError: x

No debugging capability is lost, as the original exception context remains available if needed (for example, if an intervening library has incorrectly suppressed valuable underlying details):

>>> try:
...     D({}).x
... except AttributeError as exc:
...     print(repr(exc.__context__))
...
KeyError('x',)

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PEP 409 [https://peps.python.org/pep-0409/] - Suppressing exception context

PEP written by Ethan Furman; implemented by Ethan Furman and Nick Coghlan.

PEP 414: Explicit Unicode literals

To ease the transition from Python 2 for Unicode aware Python applications that make heavy use of Unicode literals, Python 3.3 once again supports the “u” prefix for string literals. This prefix has no semantic significance in Python 3, it is provided solely to reduce the number of purely mechanical changes in migrating to Python 3, making it easier for developers to focus on the more significant semantic changes (such as the stricter default separation of binary and text data).

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PEP 414 [https://peps.python.org/pep-0414/] - Explicit Unicode literals

PEP written by Armin Ronacher.

PEP 3155: Qualified name for classes and functions

Functions and class objects have a new __qualname__ attribute representing the “path” from the module top-level to their definition. For global functions and classes, this is the same as __name__. For other functions and classes, it provides better information about where they were actually defined, and how they might be accessible from the global scope.

Example with (non-bound) methods:

>>> class C:
...     def meth(self):
...         pass
...
>>> C.meth.__name__
'meth'
>>> C.meth.__qualname__
'C.meth'

Example with nested classes:

>>> class C:
...     class D:
...         def meth(self):
...             pass
...
>>> C.D.__name__
'D'
>>> C.D.__qualname__
'C.D'
>>> C.D.meth.__name__
'meth'
>>> C.D.meth.__qualname__
'C.D.meth'

Example with nested functions:

>>> def outer():
...     def inner():
...         pass
...     return inner
...
>>> outer().__name__
'inner'
>>> outer().__qualname__
'outer.<locals>.inner'

The string representation of those objects is also changed to include the new, more precise information:

>>> str(C.D)
"<class '__main__.C.D'>"
>>> str(C.D.meth)
'<function C.D.meth at 0x7f46b9fe31e0>'

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PEP 3155 [https://peps.python.org/pep-3155/] - Qualified name for classes and functions

PEP written and implemented by Antoine Pitrou.

PEP 412: Key-Sharing Dictionary

Dictionaries used for the storage of objects’ attributes are now able to share part of their internal storage between each other (namely, the part which stores the keys and their respective hashes). This reduces the memory consumption of programs creating many instances of non-builtin types.

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PEP 412 [https://peps.python.org/pep-0412/] - Key-Sharing Dictionary

PEP written and implemented by Mark Shannon.

PEP 362: Function Signature Object

A new function inspect.signature() makes introspection of python callables easy and straightforward. A broad range of callables is supported: python functions, decorated or not, classes, and functools.partial() objects. New classes inspect.Signature, inspect.Parameter and inspect.BoundArguments hold information about the call signatures, such as, annotations, default values, parameters kinds, and bound arguments, which considerably simplifies writing decorators and any code that validates or amends calling signatures or arguments.

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PEP 362 [https://peps.python.org/pep-0362/]: - Function Signature Object

PEP written by Brett Cannon, Yury Selivanov, Larry Hastings, Jiwon Seo; implemented by Yury Selivanov.

PEP 421: Adding sys.implementation

A new attribute on the sys module exposes details specific to the implementation of the currently running interpreter. The initial set of attributes on sys.implementation are name, version, hexversion, and cache_tag.

The intention of sys.implementation is to consolidate into one namespace the implementation-specific data used by the standard library. This allows different Python implementations to share a single standard library code base much more easily. In its initial state, sys.implementation holds only a small portion of the implementation-specific data. Over time that ratio will shift in order to make the standard library more portable.

One example of improved standard library portability is cache_tag. As of Python 3.3, sys.implementation.cache_tag is used by importlib to support PEP 3147 [https://peps.python.org/pep-3147/] compliance. Any Python implementation that uses importlib for its built-in import system may use cache_tag to control the caching behavior for modules.

SimpleNamespace

The implementation of sys.implementation also introduces a new type to Python: types.SimpleNamespace. In contrast to a mapping-based namespace, like dict, SimpleNamespace is attribute-based, like object. However, unlike object, SimpleNamespace instances are writable. This means that you can add, remove, and modify the namespace through normal attribute access.

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PEP 421 [https://peps.python.org/pep-0421/] - Adding sys.implementation

PEP written and implemented by Eric Snow.

Using importlib as the Implementation of Import

bpo-2377 [https://bugs.python.org/issue?@action=redirect&bpo=2377] - Replace __import__ w/ importlib.__import__ bpo-13959 [https://bugs.python.org/issue?@action=redirect&bpo=13959] - Re-implement parts of imp in pure Python bpo-14605 [https://bugs.python.org/issue?@action=redirect&bpo=14605] - Make import machinery explicit bpo-14646 [https://bugs.python.org/issue?@action=redirect&bpo=14646] - Require loaders set __loader__ and __package__

The __import__() function is now powered by importlib.__import__(). This work leads to the completion of “phase 2” of PEP 302 [https://peps.python.org/pep-0302/]. There are multiple benefits to this change. First, it has allowed for more of the machinery powering import to be exposed instead of being implicit and hidden within the C code. It also provides a single implementation for all Python VMs supporting Python 3.3 to use, helping to end any VM-specific deviations in import semantics. And finally it eases the maintenance of import, allowing for future growth to occur.

For the common user, there should be no visible change in semantics. For those whose code currently manipulates import or calls import programmatically, the code changes that might possibly be required are covered in the Porting Python code section of this document.

New APIs

One of the large benefits of this work is the exposure of what goes into making the import statement work. That means the various importers that were once implicit are now fully exposed as part of the importlib package.

The abstract base classes defined in importlib.abc have been expanded to properly delineate between meta path finders and path entry finders by introducing importlib.abc.MetaPathFinder and importlib.abc.PathEntryFinder, respectively. The old ABC of importlib.abc.Finder is now only provided for backwards-compatibility and does not enforce any method requirements.

In terms of finders, importlib.machinery.FileFinder exposes the mechanism used to search for source and bytecode files of a module. Previously this class was an implicit member of sys.path_hooks.

For loaders, the new abstract base class importlib.abc.FileLoader helps write a loader that uses the file system as the storage mechanism for a module’s code. The loader for source files (importlib.machinery.SourceFileLoader), sourceless bytecode files (importlib.machinery.SourcelessFileLoader), and extension modules (importlib.machinery.ExtensionFileLoader) are now available for direct use.

ImportError now has name and path attributes which are set when there is relevant data to provide. The message for failed imports will also provide the full name of the module now instead of just the tail end of the module’s name.

The importlib.invalidate_caches() function will now call the method with the same name on all finders cached in sys.path_importer_cache to help clean up any stored state as necessary.

Visible Changes

For potential required changes to code, see the Porting Python code section.

Beyond the expanse of what importlib now exposes, there are other visible changes to import. The biggest is that sys.meta_path and sys.path_hooks now store all of the meta path finders and path entry hooks used by import. Previously the finders were implicit and hidden within the C code of import instead of being directly exposed. This means that one can now easily remove or change the order of the various finders to fit one’s needs.

Another change is that all modules have a __loader__ attribute, storing the loader used to create the module. PEP 302 [https://peps.python.org/pep-0302/] has been updated to make this attribute mandatory for loaders to implement, so in the future once 3rd-party loaders have been updated people will be able to rely on the existence of the attribute. Until such time, though, import is setting the module post-load.

Loaders are also now expected to set the __package__ attribute from PEP 366 [https://peps.python.org/pep-0366/]. Once again, import itself is already setting this on all loaders from importlib and import itself is setting the attribute post-load.

None is now inserted into sys.path_importer_cache when no finder can be found on sys.path_hooks. Since imp.NullImporter is not directly exposed on sys.path_hooks it could no longer be relied upon to always be available to use as a value representing no finder found.

All other changes relate to semantic changes which should be taken into consideration when updating code for Python 3.3, and thus should be read about in the Porting Python code section of this document.

(Implementation by Brett Cannon)

Other Language Changes

Some smaller changes made to the core Python language are:

Added support for Unicode name aliases and named sequences. Both unicodedata.lookup() and '\N{...}' now resolve name aliases, and unicodedata.lookup() resolves named sequences too.

(Contributed by Ezio Melotti in bpo-12753 [https://bugs.python.org/issue?@action=redirect&bpo=12753].)

Unicode database updated to UCD version 6.1.0

Equality comparisons on range() objects now return a result reflecting the equality of the underlying sequences generated by those range objects. (bpo-13201 [https://bugs.python.org/issue?@action=redirect&bpo=13201])

The count(), find(), rfind(), index() and rindex() methods of bytes and bytearray objects now accept an integer between 0 and 255 as their first argument.

(Contributed by Petri Lehtinen in bpo-12170 [https://bugs.python.org/issue?@action=redirect&bpo=12170].)

The rjust(), ljust(), and center() methods of bytes and bytearray now accept a bytearray for the fill argument. (Contributed by Petri Lehtinen in bpo-12380 [https://bugs.python.org/issue?@action=redirect&bpo=12380].)

New methods have been added to list and bytearray: copy() and clear() (bpo-10516 [https://bugs.python.org/issue?@action=redirect&bpo=10516]). Consequently, MutableSequence now also defines a clear() method (bpo-11388 [https://bugs.python.org/issue?@action=redirect&bpo=11388]).

Raw bytes literals can now be written rb"..." as well as br"...".

(Contributed by Antoine Pitrou in bpo-13748 [https://bugs.python.org/issue?@action=redirect&bpo=13748].)

dict.setdefault() now does only one lookup for the given key, making it atomic when used with built-in types.

(Contributed by Filip Gruszczyński in bpo-13521 [https://bugs.python.org/issue?@action=redirect&bpo=13521].)

The error messages produced when a function call does not match the function signature have been significantly improved.

(Contributed by Benjamin Peterson.)

A Finer-Grained Import Lock

Previous versions of CPython have always relied on a global import lock. This led to unexpected annoyances, such as deadlocks when importing a module would trigger code execution in a different thread as a side-effect. Clumsy workarounds were sometimes employed, such as the PyImport_ImportModuleNoBlock() C API function.

In Python 3.3, importing a module takes a per-module lock. This correctly serializes importation of a given module from multiple threads (preventing the exposure of incompletely initialized modules), while eliminating the aforementioned annoyances.

(Contributed by Antoine Pitrou in bpo-9260 [https://bugs.python.org/issue?@action=redirect&bpo=9260].)

Builtin functions and types

open() gets a new opener parameter: the underlying file descriptor for the file object is then obtained by calling opener with (file, flags). It can be used to use custom flags like os.O_CLOEXEC for example. The 'x' mode was added: open for exclusive creation, failing if the file already exists.

print(): added the flush keyword argument. If the flush keyword argument is true, the stream is forcibly flushed.

hash(): hash randomization is enabled by default, see object.__hash__() and PYTHONHASHSEED.

The str type gets a new casefold() method: return a casefolded copy of the string, casefolded strings may be used for caseless matching. For example, 'ß'.casefold() returns 'ss'.

The sequence documentation has been substantially rewritten to better explain the binary/text sequence distinction and to provide specific documentation sections for the individual builtin sequence types (bpo-4966 [https://bugs.python.org/issue?@action=redirect&bpo=4966]).

New Modules

faulthandler

This new debug module faulthandler contains functions to dump Python tracebacks explicitly, on a fault (a crash like a segmentation fault), after a timeout, or on a user signal. Call faulthandler.enable() to install fault handlers for the SIGSEGV, SIGFPE, SIGABRT, SIGBUS, and SIGILL signals. You can also enable them at startup by setting the PYTHONFAULTHANDLER environment variable or by using -X faulthandler command line option.

Example of a segmentation fault on Linux:

$ python -q -X faulthandler
>>> import ctypes
>>> ctypes.string_at(0)
Fatal Python error: Segmentation fault

Current thread 0x00007fb899f39700:
  File "/home/python/cpython/Lib/ctypes/__init__.py", line 486 in string_at
  File "<stdin>", line 1 in <module>
Segmentation fault

ipaddress

The new ipaddress module provides tools for creating and manipulating objects representing IPv4 and IPv6 addresses, networks and interfaces (i.e. an IP address associated with a specific IP subnet).

(Contributed by Google and Peter Moody in PEP 3144 [https://peps.python.org/pep-3144/].)

lzma

The newly added lzma module provides data compression and decompression using the LZMA algorithm, including support for the .xz and .lzma file formats.

(Contributed by Nadeem Vawda and Per Øyvind Karlsen in bpo-6715 [https://bugs.python.org/issue?@action=redirect&bpo=6715].)

Improved Modules

abc

Improved support for abstract base classes containing descriptors composed with abstract methods. The recommended approach to declaring abstract descriptors is now to provide __isabstractmethod__ as a dynamically updated property. The built-in descriptors have been updated accordingly.

abc.abstractproperty has been deprecated, use property with abc.abstractmethod() instead.

abc.abstractclassmethod has been deprecated, use classmethod with abc.abstractmethod() instead.

abc.abstractstaticmethod has been deprecated, use staticmethod with abc.abstractmethod() instead.

(Contributed by Darren Dale in bpo-11610 [https://bugs.python.org/issue?@action=redirect&bpo=11610].)

abc.ABCMeta.register() now returns the registered subclass, which means it can now be used as a class decorator (bpo-10868 [https://bugs.python.org/issue?@action=redirect&bpo=10868]).

array

The array module supports the long long type using q and Q type codes.

(Contributed by Oren Tirosh and Hirokazu Yamamoto in bpo-1172711 [https://bugs.python.org/issue?@action=redirect&bpo=1172711].)

base64

ASCII-only Unicode strings are now accepted by the decoding functions of the base64 modern interface. For example, base64.b64decode('YWJj') returns b'abc'. (Contributed by Catalin Iacob in bpo-13641 [https://bugs.python.org/issue?@action=redirect&bpo=13641].)

binascii

In addition to the binary objects they normally accept, the a2b_ functions now all also accept ASCII-only strings as input. (Contributed by Antoine Pitrou in bpo-13637 [https://bugs.python.org/issue?@action=redirect&bpo=13637].)

bz2

The bz2 module has been rewritten from scratch. In the process, several new features have been added:

New bz2.open() function: open a bzip2-compressed file in binary or text mode.

bz2.BZ2File can now read from and write to arbitrary file-like objects, by means of its constructor’s fileobj argument.

(Contributed by Nadeem Vawda in bpo-5863 [https://bugs.python.org/issue?@action=redirect&bpo=5863].)

bz2.BZ2File and bz2.decompress() can now decompress multi-stream inputs (such as those produced by the pbzip2 tool). bz2.BZ2File can now also be used to create this type of file, using the 'a' (append) mode.

(Contributed by Nir Aides in bpo-1625 [https://bugs.python.org/issue?@action=redirect&bpo=1625].)

bz2.BZ2File now implements all of the io.BufferedIOBase API, except for the detach() and truncate() methods.

codecs

The mbcs codec has been rewritten to handle correctly replace and ignore error handlers on all Windows versions. The mbcs codec now supports all error handlers, instead of only replace to encode and ignore to decode.

A new Windows-only codec has been added: cp65001 (bpo-13216 [https://bugs.python.org/issue?@action=redirect&bpo=13216]). It is the Windows code page 65001 (Windows UTF-8, CP_UTF8). For example, it is used by sys.stdout if the console output code page is set to cp65001 (e.g., using chcp 65001 command).

Multibyte CJK decoders now resynchronize faster. They only ignore the first byte of an invalid byte sequence. For example, b'\xff\n'.decode('gb2312', 'replace') now returns a \n after the replacement character.

(bpo-12016 [https://bugs.python.org/issue?@action=redirect&bpo=12016])

Incremental CJK codec encoders are no longer reset at each call to their encode() methods. For example:

>>> import codecs
>>> encoder = codecs.getincrementalencoder('hz')('strict')
>>> b''.join(encoder.encode(x) for x in '\u52ff\u65bd\u65bc\u4eba\u3002 Bye.')
b'~{NpJ)l6HK!#~} Bye.'

This example gives b'~{Np~}~{J)~}~{l6~}~{HK~}~{!#~} Bye.' with older Python versions.

(bpo-12100 [https://bugs.python.org/issue?@action=redirect&bpo=12100])

The unicode_internal codec has been deprecated.

collections

Addition of a new ChainMap class to allow treating a number of mappings as a single unit. (Written by Raymond Hettinger for bpo-11089 [https://bugs.python.org/issue?@action=redirect&bpo=11089], made public in bpo-11297 [https://bugs.python.org/issue?@action=redirect&bpo=11297].)

The abstract base classes have been moved in a new collections.abc module, to better differentiate between the abstract and the concrete collections classes. Aliases for ABCs are still present in the collections module to preserve existing imports. (bpo-11085 [https://bugs.python.org/issue?@action=redirect&bpo=11085])

The Counter class now supports the unary + and - operators, as well as the in-place operators +=, -=, |=, and &=. (Contributed by Raymond Hettinger in bpo-13121 [https://bugs.python.org/issue?@action=redirect&bpo=13121].)

contextlib

ExitStack now provides a solid foundation for programmatic manipulation of context managers and similar cleanup functionality. Unlike the previous contextlib.nested API (which was deprecated and removed), the new API is designed to work correctly regardless of whether context managers acquire their resources in their __init__ method (for example, file objects) or in their __enter__ method (for example, synchronisation objects from the threading module).

(bpo-13585 [https://bugs.python.org/issue?@action=redirect&bpo=13585])

crypt

Addition of salt and modular crypt format (hashing method) and the mksalt() function to the crypt module.

(bpo-10924 [https://bugs.python.org/issue?@action=redirect&bpo=10924])

curses

If the curses module is linked to the ncursesw library, use Unicode functions when Unicode strings or characters are passed (e.g. waddwstr()), and bytes functions otherwise (e.g. waddstr()).

Use the locale encoding instead of utf-8 to encode Unicode strings.

curses.window has a new curses.window.encoding attribute.

The curses.window class has a new get_wch() method to get a wide character

The curses module has a new unget_wch() function to push a wide character so the next get_wch() will return it

(Contributed by Iñigo Serna in bpo-6755 [https://bugs.python.org/issue?@action=redirect&bpo=6755].)

datetime

Equality comparisons between naive and aware datetime instances now return False instead of raising TypeError (bpo-15006 [https://bugs.python.org/issue?@action=redirect&bpo=15006]).

New datetime.datetime.timestamp() method: Return POSIX timestamp corresponding to the datetime instance.

The datetime.datetime.strftime() method supports formatting years older than 1000.

The datetime.datetime.astimezone() method can now be called without arguments to convert datetime instance to the system timezone.

decimal

bpo-7652 [https://bugs.python.org/issue?@action=redirect&bpo=7652] - integrate fast native decimal arithmetic.

C-module and libmpdec written by Stefan Krah.

The new C version of the decimal module integrates the high speed libmpdec library for arbitrary precision correctly rounded decimal floating-point arithmetic. libmpdec conforms to IBM’s General Decimal Arithmetic Specification.

Performance gains range from 10x for database applications to 100x for numerically intensive applications. These numbers are expected gains for standard precisions used in decimal floating-point arithmetic. Since the precision is user configurable, the exact figures may vary. For example, in integer bignum arithmetic the differences can be significantly higher.

The following table is meant as an illustration. Benchmarks are available at https://www.bytereef.org/mpdecimal/quickstart.html.

decimal.py

_decimal

speedup

pi

42.02s

0.345s

120x

telco

172.19s

5.68s

30x

psycopg

3.57s

0.29s

12x

Features

The FloatOperation signal optionally enables stricter semantics for mixing floats and Decimals.

If Python is compiled without threads, the C version automatically disables the expensive thread local context machinery. In this case, the variable HAVE_THREADS is set to False.

API changes

The C module has the following context limits, depending on the machine architecture:

32-bit

64-bit

MAX_PREC

425000000

999999999999999999

MAX_EMAX

425000000

999999999999999999

MIN_EMIN

-425000000

-999999999999999999

In the context templates (DefaultContext, BasicContext and ExtendedContext) the magnitude of Emax and Emin has changed to 999999.

The Decimal constructor in decimal.py does not observe the context limits and converts values with arbitrary exponents or precision exactly. Since the C version has internal limits, the following scheme is used: If possible, values are converted exactly, otherwise InvalidOperation is raised and the result is NaN. In the latter case it is always possible to use create_decimal() in order to obtain a rounded or inexact value.

The power function in decimal.py is always correctly rounded. In the C version, it is defined in terms of the correctly rounded exp() and ln() functions, but the final result is only “almost always correctly rounded”.

In the C version, the context dictionary containing the signals is a MutableMapping. For speed reasons, flags and traps always refer to the same MutableMapping that the context was initialized with. If a new signal dictionary is assigned, flags and traps are updated with the new values, but they do not reference the RHS dictionary.

Pickling a Context produces a different output in order to have a common interchange format for the Python and C versions.

The order of arguments in the Context constructor has been changed to match the order displayed by repr().

The watchexp parameter in the quantize() method is deprecated.

email

Policy Framework

The email package now has a policy framework. A Policy is an object with several methods and properties that control how the email package behaves. The primary policy for Python 3.3 is the Compat32 policy, which provides backward compatibility with the email package in Python 3.2. A policy can be specified when an email message is parsed by a parser, or when a Message object is created, or when an email is serialized using a generator. Unless overridden, a policy passed to a parser is inherited by all the Message object and sub-objects created by the parser. By default a generator will use the policy of the Message object it is serializing. The default policy is compat32.

The minimum set of controls implemented by all policy objects are:

max_line_length

The maximum length, excluding the linesep character(s), individual lines may have when a Message is serialized. Defaults to 78.

linesep

The character used to separate individual lines when a Message is serialized. Defaults to \n.

cte_type

7bit or 8bit. 8bit applies only to a Bytes generator, and means that non-ASCII may be used where allowed by the protocol (or where it exists in the original input).

raise_on_defect

Causes a parser to raise error when defects are encountered instead of adding them to the Message object’s defects list.

A new policy instance, with new settings, is created using the clone() method of policy objects. clone takes any of the above controls as keyword arguments. Any control not specified in the call retains its default value. Thus you can create a policy that uses \r\n linesep characters like this:

mypolicy = compat32.clone(linesep='\r\n')

Policies can be used to make the generation of messages in the format needed by your application simpler. Instead of having to remember to specify linesep='\r\n' in all the places you call a generator, you can specify it once, when you set the policy used by the parser or the Message, whichever your program uses to create Message objects. On the other hand, if you need to generate messages in multiple forms, you can still specify the parameters in the appropriate generator call. Or you can have custom policy instances for your different cases, and pass those in when you create the generator.

Provisional Policy with New Header API

While the policy framework is worthwhile all by itself, the main motivation for introducing it is to allow the creation of new policies that implement new features for the email package in a way that maintains backward compatibility for those who do not use the new policies. Because the new policies introduce a new API, we are releasing them in Python 3.3 as a provisional policy. Backwards incompatible changes (up to and including removal of the code) may occur if deemed necessary by the core developers.

The new policies are instances of EmailPolicy, and add the following additional controls:

refold_source

Controls whether or not headers parsed by a parser are refolded by the generator. It can be none, long, or all. The default is long, which means that source headers with a line longer than max_line_length get refolded. none means no line get refolded, and all means that all lines get refolded.

header_factory

A callable that take a name and value and produces a custom header object.

The header_factory is the key to the new features provided by the new policies. When one of the new policies is used, any header retrieved from a Message object is an object produced by the header_factory, and any time you set a header on a Message it becomes an object produced by header_factory. All such header objects have a name attribute equal to the header name. Address and Date headers have additional attributes that give you access to the parsed data of the header. This means you can now do things like this:

>>> m = Message(policy=SMTP)
>>> m['To'] = 'Éric <foo@example.com>'
>>> m['to']
'Éric <foo@example.com>'
>>> m['to'].addresses
(Address(display_name='Éric', username='foo', domain='example.com'),)
>>> m['to'].addresses[0].username
'foo'
>>> m['to'].addresses[0].display_name
'Éric'
>>> m['Date'] = email.utils.localtime()
>>> m['Date'].datetime
datetime.datetime(2012, 5, 25, 21, 39, 24, 465484, tzinfo=datetime.timezone(datetime.timedelta(-1, 72000), 'EDT'))
>>> m['Date']
'Fri, 25 May 2012 21:44:27 -0400'
>>> print(m)
To: =?utf-8?q?=C3=89ric?= <foo@example.com>
Date: Fri, 25 May 2012 21:44:27 -0400

You will note that the unicode display name is automatically encoded as utf-8 when the message is serialized, but that when the header is accessed directly, you get the unicode version. This eliminates any need to deal with the email.header decode_header() or make_header() functions.

You can also create addresses from parts:

>>> m['cc'] = [Group('pals', [Address('Bob', 'bob', 'example.com'),
...                           Address('Sally', 'sally', 'example.com')]),
...            Address('Bonzo', addr_spec='bonz@laugh.com')]
>>> print(m)
To: =?utf-8?q?=C3=89ric?= <foo@example.com>
Date: Fri, 25 May 2012 21:44:27 -0400
cc: pals: Bob <bob@example.com>, Sally <sally@example.com>;, Bonzo <bonz@laugh.com>

Decoding to unicode is done automatically:

>>> m2 = message_from_string(str(m))
>>> m2['to']
'Éric <foo@example.com>'

When you parse a message, you can use the addresses and groups attributes of the header objects to access the groups and individual addresses:

>>> m2['cc'].addresses
(Address(display_name='Bob', username='bob', domain='example.com'), Address(display_name='Sally', username='sally', domain='example.com'), Address(display_name='Bonzo', username='bonz', domain='laugh.com'))
>>> m2['cc'].groups
(Group(display_name='pals', addresses=(Address(display_name='Bob', username='bob', domain='example.com'), Address(display_name='Sally', username='sally', domain='example.com')), Group(display_name=None, addresses=(Address(display_name='Bonzo', username='bonz', domain='laugh.com'),))

In summary, if you use one of the new policies, header manipulation works the way it ought to: your application works with unicode strings, and the email package transparently encodes and decodes the unicode to and from the RFC standard Content Transfer Encodings.

Other API Changes

New BytesHeaderParser, added to the parser module to complement HeaderParser and complete the Bytes API.

New utility functions:

format_datetime(): given a datetime, produce a string formatted for use in an email header.

parsedate_to_datetime(): given a date string from an email header, convert it into an aware datetime, or a naive datetime if the offset is -0000.

localtime(): With no argument, returns the current local time as an aware datetime using the local timezone. Given an aware datetime, converts it into an aware datetime using the local timezone.

ftplib

ftplib.FTP now accepts a source_address keyword argument to specify the (host, port) to use as the source address in the bind call when creating the outgoing socket. (Contributed by Giampaolo Rodolà in bpo-8594 [https://bugs.python.org/issue?@action=redirect&bpo=8594].)

The FTP_TLS class now provides a new ccc() function to revert control channel back to plaintext. This can be useful to take advantage of firewalls that know how to handle NAT with non-secure FTP without opening fixed ports. (Contributed by Giampaolo Rodolà in bpo-12139 [https://bugs.python.org/issue?@action=redirect&bpo=12139].)

Added ftplib.FTP.mlsd() method which provides a parsable directory listing format and deprecates ftplib.FTP.nlst() and ftplib.FTP.dir(). (Contributed by Giampaolo Rodolà in bpo-11072 [https://bugs.python.org/issue?@action=redirect&bpo=11072].)

functools

The functools.lru_cache() decorator now accepts a typed keyword argument (that defaults to False to ensure that it caches values of different types that compare equal in separate cache slots. (Contributed by Raymond Hettinger in bpo-13227 [https://bugs.python.org/issue?@action=redirect&bpo=13227].)

gc

It is now possible to register callbacks invoked by the garbage collector before and after collection using the new callbacks list.

hmac

A new compare_digest() function has been added to prevent side channel attacks on digests through timing analysis. (Contributed by Nick Coghlan and Christian Heimes in bpo-15061 [https://bugs.python.org/issue?@action=redirect&bpo=15061].)

http

http.server.BaseHTTPRequestHandler now buffers the headers and writes them all at once when end_headers() is called. A new method flush_headers() can be used to directly manage when the accumulated headers are sent. (Contributed by Andrew Schaaf in bpo-3709 [https://bugs.python.org/issue?@action=redirect&bpo=3709].)

http.server now produces valid HTML 4.01 strict output. (Contributed by Ezio Melotti in bpo-13295 [https://bugs.python.org/issue?@action=redirect&bpo=13295].)

http.client.HTTPResponse now has a readinto() method, which means it can be used as an io.RawIOBase class. (Contributed by John Kuhn in bpo-13464 [https://bugs.python.org/issue?@action=redirect&bpo=13464].)

html

html.parser.HTMLParser is now able to parse broken markup without raising errors, therefore the strict argument of the constructor and the HTMLParseError exception are now deprecated. The ability to parse broken markup is the result of a number of bug fixes that are also available on the latest bug fix releases of Python 2.7/3.2. (Contributed by Ezio Melotti in bpo-15114 [https://bugs.python.org/issue?@action=redirect&bpo=15114], and bpo-14538 [https://bugs.python.org/issue?@action=redirect&bpo=14538], bpo-13993 [https://bugs.python.org/issue?@action=redirect&bpo=13993], bpo-13960 [https://bugs.python.org/issue?@action=redirect&bpo=13960], bpo-13358 [https://bugs.python.org/issue?@action=redirect&bpo=13358], bpo-1745761 [https://bugs.python.org/issue?@action=redirect&bpo=1745761], bpo-755670 [https://bugs.python.org/issue?@action=redirect&bpo=755670], bpo-13357 [https://bugs.python.org/issue?@action=redirect&bpo=13357], bpo-12629 [https://bugs.python.org/issue?@action=redirect&bpo=12629], bpo-1200313 [https://bugs.python.org/issue?@action=redirect&bpo=1200313], bpo-670664 [https://bugs.python.org/issue?@action=redirect&bpo=670664], bpo-13273 [https://bugs.python.org/issue?@action=redirect&bpo=13273], bpo-12888 [https://bugs.python.org/issue?@action=redirect&bpo=12888], bpo-7311 [https://bugs.python.org/issue?@action=redirect&bpo=7311].)

A new html5 dictionary that maps HTML5 named character references to the equivalent Unicode character(s) (e.g. html5['gt;'] == '>') has been added to the html.entities module. The dictionary is now also used by HTMLParser. (Contributed by Ezio Melotti in bpo-11113 [https://bugs.python.org/issue?@action=redirect&bpo=11113] and bpo-15156 [https://bugs.python.org/issue?@action=redirect&bpo=15156].)

imaplib

The IMAP4_SSL constructor now accepts an SSLContext parameter to control parameters of the secure channel.

(Contributed by Sijin Joseph in bpo-8808 [https://bugs.python.org/issue?@action=redirect&bpo=8808].)

inspect

A new getclosurevars() function has been added. This function reports the current binding of all names referenced from the function body and where those names were resolved, making it easier to verify correct internal state when testing code that relies on stateful closures.

(Contributed by Meador Inge and Nick Coghlan in bpo-13062 [https://bugs.python.org/issue?@action=redirect&bpo=13062].)

A new getgeneratorlocals() function has been added. This function reports the current binding of local variables in the generator’s stack frame, making it easier to verify correct internal state when testing generators.

(Contributed by Meador Inge in bpo-15153 [https://bugs.python.org/issue?@action=redirect&bpo=15153].)

io

The open() function has a new 'x' mode that can be used to exclusively create a new file, and raise a FileExistsError if the file already exists. It is based on the C11 ‘x’ mode to fopen().

(Contributed by David Townshend in bpo-12760 [https://bugs.python.org/issue?@action=redirect&bpo=12760].)

The constructor of the TextIOWrapper class has a new write_through optional argument. If write_through is True, calls to write() are guaranteed not to be buffered: any data written on the TextIOWrapper object is immediately handled to its underlying binary buffer.

itertools

accumulate() now takes an optional func argument for providing a user-supplied binary function.

logging

The basicConfig() function now supports an optional handlers argument taking an iterable of handlers to be added to the root logger.

A class level attribute append_nul has been added to SysLogHandler to allow control of the appending of the NUL (\000) byte to syslog records, since for some daemons it is required while for others it is passed through to the log.

math

The math module has a new function, log2(), which returns the base-2 logarithm of x.

(Written by Mark Dickinson in bpo-11888 [https://bugs.python.org/issue?@action=redirect&bpo=11888].)

mmap

The read() method is now more compatible with other file-like objects: if the argument is omitted or specified as None, it returns the bytes from the current file position to the end of the mapping. (Contributed by Petri Lehtinen in bpo-12021 [https://bugs.python.org/issue?@action=redirect&bpo=12021].)

multiprocessing

The new multiprocessing.connection.wait() function allows polling multiple objects (such as connections, sockets and pipes) with a timeout. (Contributed by Richard Oudkerk in bpo-12328 [https://bugs.python.org/issue?@action=redirect&bpo=12328].)

multiprocessing.Connection objects can now be transferred over multiprocessing connections. (Contributed by Richard Oudkerk in bpo-4892 [https://bugs.python.org/issue?@action=redirect&bpo=4892].)

multiprocessing.Process now accepts a daemon keyword argument to override the default behavior of inheriting the daemon flag from the parent process (bpo-6064 [https://bugs.python.org/issue?@action=redirect&bpo=6064]).

New attribute multiprocessing.Process.sentinel allows a program to wait on multiple Process objects at one time using the appropriate OS primitives (for example, select on posix systems).

New methods multiprocessing.pool.Pool.starmap() and starmap_async() provide itertools.starmap() equivalents to the existing multiprocessing.pool.Pool.map() and map_async() functions. (Contributed by Hynek Schlawack in bpo-12708 [https://bugs.python.org/issue?@action=redirect&bpo=12708].)

nntplib

The nntplib.NNTP class now supports the context management protocol to unconditionally consume socket.error exceptions and to close the NNTP connection when done:

>>> from nntplib import NNTP
>>> with NNTP('news.gmane.org') as n:
...     n.group('gmane.comp.python.committers')
...
('211 1755 1 1755 gmane.comp.python.committers', 1755, 1, 1755, 'gmane.comp.python.committers')
>>>

(Contributed by Giampaolo Rodolà in bpo-9795 [https://bugs.python.org/issue?@action=redirect&bpo=9795].)

os

The os module has a new pipe2() function that makes it possible to create a pipe with O_CLOEXEC or O_NONBLOCK flags set atomically. This is especially useful to avoid race conditions in multi-threaded programs.

The os module has a new sendfile() function which provides an efficient “zero-copy” way for copying data from one file (or socket) descriptor to another. The phrase “zero-copy” refers to the fact that all of the copying of data between the two descriptors is done entirely by the kernel, with no copying of data into userspace buffers. sendfile() can be used to efficiently copy data from a file on disk to a network socket, e.g. for downloading a file.

(Patch submitted by Ross Lagerwall and Giampaolo Rodolà in bpo-10882 [https://bugs.python.org/issue?@action=redirect&bpo=10882].)

To avoid race conditions like symlink attacks and issues with temporary files and directories, it is more reliable (and also faster) to manipulate file descriptors instead of file names. Python 3.3 enhances existing functions and introduces new functions to work on file descriptors (bpo-4761 [https://bugs.python.org/issue?@action=redirect&bpo=4761], bpo-10755 [https://bugs.python.org/issue?@action=redirect&bpo=10755] and bpo-14626 [https://bugs.python.org/issue?@action=redirect&bpo=14626]).

The os module has a new fwalk() function similar to walk() except that it also yields file descriptors referring to the directories visited. This is especially useful to avoid symlink races.

The following functions get new optional dir_fd (paths relative to directory descriptors) and/or follow_symlinks (not following symlinks): access(), chflags(), chmod(), chown(), link(), lstat(), mkdir(), mkfifo(), mknod(), open(), readlink(), remove(), rename(), replace(), rmdir(), stat(), symlink(), unlink(), utime(). Platform support for using these parameters can be checked via the sets os.supports_dir_fd and os.supports_follows_symlinks.

The following functions now support a file descriptor for their path argument: chdir(), chmod(), chown(), execve(), listdir(), pathconf(), exists(), stat(), statvfs(), utime(). Platform support for this can be checked via the os.supports_fd set.

access() accepts an effective_ids keyword argument to turn on using the effective uid/gid rather than the real uid/gid in the access check. Platform support for this can be checked via the supports_effective_ids set.

The os module has two new functions: getpriority() and setpriority(). They can be used to get or set process niceness/priority in a fashion similar to os.nice() but extended to all processes instead of just the current one.

(Patch submitted by Giampaolo Rodolà in bpo-10784 [https://bugs.python.org/issue?@action=redirect&bpo=10784].)

The new os.replace() function allows cross-platform renaming of a file with overwriting the destination. With os.rename(), an existing destination file is overwritten under POSIX, but raises an error under Windows. (Contributed by Antoine Pitrou in bpo-8828 [https://bugs.python.org/issue?@action=redirect&bpo=8828].)

The stat family of functions (stat(), fstat(), and lstat()) now support reading a file’s timestamps with nanosecond precision. Symmetrically, utime() can now write file timestamps with nanosecond precision. (Contributed by Larry Hastings in bpo-14127 [https://bugs.python.org/issue?@action=redirect&bpo=14127].)

The new os.get_terminal_size() function queries the size of the terminal attached to a file descriptor. See also shutil.get_terminal_size(). (Contributed by Zbigniew Jędrzejewski-Szmek in bpo-13609 [https://bugs.python.org/issue?@action=redirect&bpo=13609].)

New functions to support Linux extended attributes (bpo-12720 [https://bugs.python.org/issue?@action=redirect&bpo=12720]): getxattr(), listxattr(), removexattr(), setxattr().

New interface to the scheduler. These functions control how a process is allocated CPU time by the operating system. New functions: sched_get_priority_max(), sched_get_priority_min(), sched_getaffinity(), sched_getparam(), sched_getscheduler(), sched_rr_get_interval(), sched_setaffinity(), sched_setparam(), sched_setscheduler(), sched_yield(),

New functions to control the file system:

posix_fadvise(): Announces an intention to access data in a specific pattern thus allowing the kernel to make optimizations.

posix_fallocate(): Ensures that enough disk space is allocated for a file.

sync(): Force write of everything to disk.

Additional new posix functions:

lockf(): Apply, test or remove a POSIX lock on an open file descriptor.

pread(): Read from a file descriptor at an offset, the file offset remains unchanged.

pwrite(): Write to a file descriptor from an offset, leaving the file offset unchanged.

readv(): Read from a file descriptor into a number of writable buffers.

truncate(): Truncate the file corresponding to path, so that it is at most length bytes in size.

waitid(): Wait for the completion of one or more child processes.

writev(): Write the contents of buffers to a file descriptor, where buffers is an arbitrary sequence of buffers.

getgrouplist() (bpo-9344 [https://bugs.python.org/issue?@action=redirect&bpo=9344]): Return list of group ids that specified user belongs to.

times() and uname(): Return type changed from a tuple to a tuple-like object with named attributes.

Some platforms now support additional constants for the lseek() function, such as os.SEEK_HOLE and os.SEEK_DATA.

New constants RTLD_LAZY, RTLD_NOW, RTLD_GLOBAL, RTLD_LOCAL, RTLD_NODELETE, RTLD_NOLOAD, and RTLD_DEEPBIND are available on platforms that support them. These are for use with the sys.setdlopenflags() function, and supersede the similar constants defined in ctypes and DLFCN. (Contributed by Victor Stinner in bpo-13226 [https://bugs.python.org/issue?@action=redirect&bpo=13226].)

os.symlink() now accepts (and ignores) the target_is_directory keyword argument on non-Windows platforms, to ease cross-platform support.

pdb

Tab-completion is now available not only for command names, but also their arguments. For example, for the break command, function and file names are completed.

(Contributed by Georg Brandl in bpo-14210 [https://bugs.python.org/issue?@action=redirect&bpo=14210])

pickle

pickle.Pickler objects now have an optional dispatch_table attribute allowing per-pickler reduction functions to be set.

(Contributed by Richard Oudkerk in bpo-14166 [https://bugs.python.org/issue?@action=redirect&bpo=14166].)

pydoc

The Tk GUI and the serve() function have been removed from the pydoc module: pydoc -g and serve() have been deprecated in Python 3.2.

re

str regular expressions now support \u and \U escapes.

(Contributed by Serhiy Storchaka in bpo-3665 [https://bugs.python.org/issue?@action=redirect&bpo=3665].)

sched

run() now accepts a blocking parameter which when set to false makes the method execute the scheduled events due to expire soonest (if any) and then return immediately. This is useful in case you want to use the scheduler in non-blocking applications. (Contributed by Giampaolo Rodolà in bpo-13449 [https://bugs.python.org/issue?@action=redirect&bpo=13449].)

scheduler class can now be safely used in multi-threaded environments. (Contributed by Josiah Carlson and Giampaolo Rodolà in bpo-8684 [https://bugs.python.org/issue?@action=redirect&bpo=8684].)

timefunc and delayfunct parameters of scheduler class constructor are now optional and defaults to time.time() and time.sleep() respectively. (Contributed by Chris Clark in bpo-13245 [https://bugs.python.org/issue?@action=redirect&bpo=13245].)

enter() and enterabs() argument parameter is now optional. (Contributed by Chris Clark in bpo-13245 [https://bugs.python.org/issue?@action=redirect&bpo=13245].)

enter() and enterabs() now accept a kwargs parameter. (Contributed by Chris Clark in bpo-13245 [https://bugs.python.org/issue?@action=redirect&bpo=13245].)

select

Solaris and derivative platforms have a new class select.devpoll for high performance asynchronous sockets via /dev/poll. (Contributed by Jesús Cea Avión in bpo-6397 [https://bugs.python.org/issue?@action=redirect&bpo=6397].)

shlex

The previously undocumented helper function quote from the pipes modules has been moved to the shlex module and documented. quote() properly escapes all characters in a string that might be otherwise given special meaning by the shell.

shutil

New functions:

disk_usage(): provides total, used and free disk space statistics. (Contributed by Giampaolo Rodolà in bpo-12442 [https://bugs.python.org/issue?@action=redirect&bpo=12442].)

chown(): allows one to change user and/or group of the given path also specifying the user/group names and not only their numeric ids. (Contributed by Sandro Tosi in bpo-12191 [https://bugs.python.org/issue?@action=redirect&bpo=12191].)

shutil.get_terminal_size(): returns the size of the terminal window to which the interpreter is attached. (Contributed by Zbigniew Jędrzejewski-Szmek in bpo-13609 [https://bugs.python.org/issue?@action=redirect&bpo=13609].)

copy2() and copystat() now preserve file timestamps with nanosecond precision on platforms that support it. They also preserve file “extended attributes” on Linux. (Contributed by Larry Hastings in bpo-14127 [https://bugs.python.org/issue?@action=redirect&bpo=14127] and bpo-15238 [https://bugs.python.org/issue?@action=redirect&bpo=15238].)

Several functions now take an optional symlinks argument: when that parameter is true, symlinks aren’t dereferenced and the operation instead acts on the symlink itself (or creates one, if relevant). (Contributed by Hynek Schlawack in bpo-12715 [https://bugs.python.org/issue?@action=redirect&bpo=12715].)

When copying files to a different file system, move() now handles symlinks the way the posix mv command does, recreating the symlink rather than copying the target file contents. (Contributed by Jonathan Niehof in bpo-9993 [https://bugs.python.org/issue?@action=redirect&bpo=9993].) move() now also returns the dst argument as its result.

rmtree() is now resistant to symlink attacks on platforms which support the new dir_fd parameter in os.open() and os.unlink(). (Contributed by Martin von Löwis and Hynek Schlawack in bpo-4489 [https://bugs.python.org/issue?@action=redirect&bpo=4489].)

signal

The signal module has new functions:

pthread_sigmask(): fetch and/or change the signal mask of the calling thread (Contributed by Jean-Paul Calderone in bpo-8407 [https://bugs.python.org/issue?@action=redirect&bpo=8407]);

pthread_kill(): send a signal to a thread;

sigpending(): examine pending functions;

sigwait(): wait a signal;

sigwaitinfo(): wait for a signal, returning detailed information about it;

sigtimedwait(): like sigwaitinfo() but with a timeout.

The signal handler writes the signal number as a single byte instead of a nul byte into the wakeup file descriptor. So it is possible to wait more than one signal and know which signals were raised.

signal.signal() and signal.siginterrupt() raise an OSError, instead of a RuntimeError: OSError has an errno attribute.

smtpd

The smtpd module now supports RFC 5321 [https://datatracker.ietf.org/doc/html/rfc5321.html] (extended SMTP) and RFC 1870 [https://datatracker.ietf.org/doc/html/rfc1870.html] (size extension). Per the standard, these extensions are enabled if and only if the client initiates the session with an EHLO command.

(Initial ELHO support by Alberto Trevino. Size extension by Juhana Jauhiainen. Substantial additional work on the patch contributed by Michele Orrù and Dan Boswell. bpo-8739 [https://bugs.python.org/issue?@action=redirect&bpo=8739])

smtplib

The SMTP, SMTP_SSL, and LMTP classes now accept a source_address keyword argument to specify the (host, port) to use as the source address in the bind call when creating the outgoing socket. (Contributed by Paulo Scardine in bpo-11281 [https://bugs.python.org/issue?@action=redirect&bpo=11281].)

SMTP now supports the context management protocol, allowing an SMTP instance to be used in a with statement. (Contributed by Giampaolo Rodolà in bpo-11289 [https://bugs.python.org/issue?@action=redirect&bpo=11289].)

The SMTP_SSL constructor and the starttls() method now accept an SSLContext parameter to control parameters of the secure channel. (Contributed by Kasun Herath in bpo-8809 [https://bugs.python.org/issue?@action=redirect&bpo=8809].)

socket

The socket class now exposes additional methods to process ancillary data when supported by the underlying platform:

sendmsg()

recvmsg()

recvmsg_into()

(Contributed by David Watson in bpo-6560 [https://bugs.python.org/issue?@action=redirect&bpo=6560], based on an earlier patch by Heiko Wundram)

The socket class now supports the PF_CAN protocol family (https://en.wikipedia.org/wiki/Socketcan), on Linux (https://lwn.net/Articles/253425).

(Contributed by Matthias Fuchs, updated by Tiago Gonçalves in bpo-10141 [https://bugs.python.org/issue?@action=redirect&bpo=10141].)

The socket class now supports the PF_RDS protocol family (https://en.wikipedia.org/wiki/Reliable_Datagram_Sockets and https://oss.oracle.com/projects/rds [https://web.archive.org/web/20130115155505/https://oss.oracle.com/projects/rds/]).

The socket class now supports the PF_SYSTEM protocol family on OS X. (Contributed by Michael Goderbauer in bpo-13777 [https://bugs.python.org/issue?@action=redirect&bpo=13777].)

New function sethostname() allows the hostname to be set on Unix systems if the calling process has sufficient privileges. (Contributed by Ross Lagerwall in bpo-10866 [https://bugs.python.org/issue?@action=redirect&bpo=10866].)

socketserver

BaseServer now has an overridable method service_actions() that is called by the serve_forever() method in the service loop. ForkingMixIn now uses this to clean up zombie child processes. (Contributed by Justin Warkentin in bpo-11109 [https://bugs.python.org/issue?@action=redirect&bpo=11109].)

sqlite3

New sqlite3.Connection method set_trace_callback() can be used to capture a trace of all sql commands processed by sqlite. (Contributed by Torsten Landschoff in bpo-11688 [https://bugs.python.org/issue?@action=redirect&bpo=11688].)

ssl

The ssl module has two new random generation functions:

RAND_bytes(): generate cryptographically strong pseudo-random bytes.

RAND_pseudo_bytes(): generate pseudo-random bytes.

(Contributed by Victor Stinner in bpo-12049 [https://bugs.python.org/issue?@action=redirect&bpo=12049].)

The ssl module now exposes a finer-grained exception hierarchy in order to make it easier to inspect the various kinds of errors. (Contributed by Antoine Pitrou in bpo-11183 [https://bugs.python.org/issue?@action=redirect&bpo=11183].)

load_cert_chain() now accepts a password argument to be used if the private key is encrypted. (Contributed by Adam Simpkins in bpo-12803 [https://bugs.python.org/issue?@action=redirect&bpo=12803].)

Diffie-Hellman key exchange, both regular and Elliptic Curve-based, is now supported through the load_dh_params() and set_ecdh_curve() methods. (Contributed by Antoine Pitrou in bpo-13626 [https://bugs.python.org/issue?@action=redirect&bpo=13626] and bpo-13627 [https://bugs.python.org/issue?@action=redirect&bpo=13627].)

SSL sockets have a new get_channel_binding() method allowing the implementation of certain authentication mechanisms such as SCRAM-SHA-1-PLUS. (Contributed by Jacek Konieczny in bpo-12551 [https://bugs.python.org/issue?@action=redirect&bpo=12551].)

You can query the SSL compression algorithm used by an SSL socket, thanks to its new compression() method. The new attribute OP_NO_COMPRESSION can be used to disable compression. (Contributed by Antoine Pitrou in bpo-13634 [https://bugs.python.org/issue?@action=redirect&bpo=13634].)

Support has been added for the Next Protocol Negotiation extension using the ssl.SSLContext.set_npn_protocols() method. (Contributed by Colin Marc in bpo-14204 [https://bugs.python.org/issue?@action=redirect&bpo=14204].)

SSL errors can now be introspected more easily thanks to library and reason attributes. (Contributed by Antoine Pitrou in bpo-14837 [https://bugs.python.org/issue?@action=redirect&bpo=14837].)

The get_server_certificate() function now supports IPv6. (Contributed by Charles-François Natali in bpo-11811 [https://bugs.python.org/issue?@action=redirect&bpo=11811].)

New attribute OP_CIPHER_SERVER_PREFERENCE allows setting SSLv3 server sockets to use the server’s cipher ordering preference rather than the client’s (bpo-13635 [https://bugs.python.org/issue?@action=redirect&bpo=13635]).

stat

The undocumented tarfile.filemode function has been moved to stat.filemode(). It can be used to convert a file’s mode to a string of the form ‘-rwxrwxrwx’.

(Contributed by Giampaolo Rodolà in bpo-14807 [https://bugs.python.org/issue?@action=redirect&bpo=14807].)

struct

The struct module now supports ssize_t and size_t via the new codes n and N, respectively. (Contributed by Antoine Pitrou in bpo-3163 [https://bugs.python.org/issue?@action=redirect&bpo=3163].)

subprocess

Command strings can now be bytes objects on posix platforms. (Contributed by Victor Stinner in bpo-8513 [https://bugs.python.org/issue?@action=redirect&bpo=8513].)

A new constant DEVNULL allows suppressing output in a platform-independent fashion. (Contributed by Ross Lagerwall in bpo-5870 [https://bugs.python.org/issue?@action=redirect&bpo=5870].)

sys

The sys module has a new thread_info named tuple holding information about the thread implementation (bpo-11223 [https://bugs.python.org/issue?@action=redirect&bpo=11223]).

tarfile

tarfile now supports lzma encoding via the lzma module. (Contributed by Lars Gustäbel in bpo-5689 [https://bugs.python.org/issue?@action=redirect&bpo=5689].)

tempfile

tempfile.SpooledTemporaryFile's truncate() method now accepts a size parameter. (Contributed by Ryan Kelly in bpo-9957 [https://bugs.python.org/issue?@action=redirect&bpo=9957].)

textwrap

The textwrap module has a new indent() that makes it straightforward to add a common prefix to selected lines in a block of text (bpo-13857 [https://bugs.python.org/issue?@action=redirect&bpo=13857]).

threading

threading.Condition, threading.Semaphore, threading.BoundedSemaphore, threading.Event, and threading.Timer, all of which used to be factory functions returning a class instance, are now classes and may be subclassed. (Contributed by Éric Araujo in bpo-10968 [https://bugs.python.org/issue?@action=redirect&bpo=10968].)

The threading.Thread constructor now accepts a daemon keyword argument to override the default behavior of inheriting the daemon flag value from the parent thread (bpo-6064 [https://bugs.python.org/issue?@action=redirect&bpo=6064]).

The formerly private function _thread.get_ident is now available as the public function threading.get_ident(). This eliminates several cases of direct access to the _thread module in the stdlib. Third party code that used _thread.get_ident should likewise be changed to use the new public interface.

time

The PEP 418 [https://peps.python.org/pep-0418/] added new functions to the time module:

get_clock_info(): Get information on a clock.

monotonic(): Monotonic clock (cannot go backward), not affected by system clock updates.

perf_counter(): Performance counter with the highest available resolution to measure a short duration.

process_time(): Sum of the system and user CPU time of the current process.

Other new functions:

clock_getres(), clock_gettime() and clock_settime() functions with CLOCK_xxx constants. (Contributed by Victor Stinner in bpo-10278 [https://bugs.python.org/issue?@action=redirect&bpo=10278].)

To improve cross platform consistency, sleep() now raises a ValueError when passed a negative sleep value. Previously this was an error on posix, but produced an infinite sleep on Windows.

types

Add a new types.MappingProxyType class: Read-only proxy of a mapping. (bpo-14386 [https://bugs.python.org/issue?@action=redirect&bpo=14386])

The new functions types.new_class() and types.prepare_class() provide support for PEP 3115 [https://peps.python.org/pep-3115/] compliant dynamic type creation. (bpo-14588 [https://bugs.python.org/issue?@action=redirect&bpo=14588])

unittest

assertRaises(), assertRaisesRegex(), assertWarns(), and assertWarnsRegex() now accept a keyword argument msg when used as context managers. (Contributed by Ezio Melotti and Winston Ewert in bpo-10775 [https://bugs.python.org/issue?@action=redirect&bpo=10775].)

unittest.TestCase.run() now returns the TestResult object.

urllib

The Request class, now accepts a method argument used by get_method() to determine what HTTP method should be used. For example, this will send a 'HEAD' request:

>>> urlopen(Request('https://www.python.org', method='HEAD'))

(bpo-1673007 [https://bugs.python.org/issue?@action=redirect&bpo=1673007])

webbrowser

The webbrowser module supports more “browsers”: Google Chrome (named chrome, chromium, chrome-browser or chromium-browser depending on the version and operating system), and the generic launchers xdg-open, from the FreeDesktop.org project, and gvfs-open, which is the default URI handler for GNOME 3. (The former contributed by Arnaud Calmettes in bpo-13620 [https://bugs.python.org/issue?@action=redirect&bpo=13620], the latter by Matthias Klose in bpo-14493 [https://bugs.python.org/issue?@action=redirect&bpo=14493].)

xml.etree.ElementTree

The xml.etree.ElementTree module now imports its C accelerator by default; there is no longer a need to explicitly import xml.etree.cElementTree (this module stays for backwards compatibility, but is now deprecated). In addition, the iter family of methods of Element has been optimized (rewritten in C). The module’s documentation has also been greatly improved with added examples and a more detailed reference.

zlib

New attribute zlib.Decompress.eof makes it possible to distinguish between a properly formed compressed stream and an incomplete or truncated one. (Contributed by Nadeem Vawda in bpo-12646 [https://bugs.python.org/issue?@action=redirect&bpo=12646].)

New attribute zlib.ZLIB_RUNTIME_VERSION reports the version string of the underlying zlib library that is loaded at runtime. (Contributed by Torsten Landschoff in bpo-12306 [https://bugs.python.org/issue?@action=redirect&bpo=12306].)

Optimizations

Major performance enhancements have been added:

Thanks to PEP 393 [https://peps.python.org/pep-0393/], some operations on Unicode strings have been optimized:

the memory footprint is divided by 2 to 4 depending on the text

encode an ASCII string to UTF-8 doesn’t need to encode characters anymore, the UTF-8 representation is shared with the ASCII representation

the UTF-8 encoder has been optimized

repeating a single ASCII letter and getting a substring of an ASCII string is 4 times faster

UTF-8 is now 2x to 4x faster. UTF-16 encoding is now up to 10x faster.

(Contributed by Serhiy Storchaka, bpo-14624 [https://bugs.python.org/issue?@action=redirect&bpo=14624], bpo-14738 [https://bugs.python.org/issue?@action=redirect&bpo=14738] and bpo-15026 [https://bugs.python.org/issue?@action=redirect&bpo=15026].)

Build and C API Changes

Changes to Python’s build process and to the C API include:

New PEP 3118 [https://peps.python.org/pep-3118/] related function:

PyMemoryView_FromMemory()

PEP 393 [https://peps.python.org/pep-0393/] added new Unicode types, macros and functions:

High-level API:

PyUnicode_CopyCharacters()

PyUnicode_FindChar()

PyUnicode_GetLength(), PyUnicode_GET_LENGTH

PyUnicode_New()

PyUnicode_Substring()

PyUnicode_ReadChar(), PyUnicode_WriteChar()

Low-level API:

Py_UCS1, Py_UCS2, Py_UCS4 types

PyASCIIObject and PyCompactUnicodeObject structures

PyUnicode_READY

PyUnicode_FromKindAndData()

PyUnicode_AsUCS4(), PyUnicode_AsUCS4Copy()

PyUnicode_DATA, PyUnicode_1BYTE_DATA, PyUnicode_2BYTE_DATA, PyUnicode_4BYTE_DATA

PyUnicode_KIND with PyUnicode_Kind enum: PyUnicode_WCHAR_KIND, PyUnicode_1BYTE_KIND, PyUnicode_2BYTE_KIND, PyUnicode_4BYTE_KIND

PyUnicode_READ, PyUnicode_READ_CHAR, PyUnicode_WRITE

PyUnicode_MAX_CHAR_VALUE

PyArg_ParseTuple now accepts a bytearray for the c format (bpo-12380 [https://bugs.python.org/issue?@action=redirect&bpo=12380]).

Deprecated

Unsupported Operating Systems

OS/2 and VMS are no longer supported due to the lack of a maintainer.

Windows 2000 and Windows platforms which set COMSPEC to command.com are no longer supported due to maintenance burden.

OSF support, which was deprecated in 3.2, has been completely removed.

Deprecated Python modules, functions and methods

Passing a non-empty string to object.__format__() is deprecated, and will produce a TypeError in Python 3.4 (bpo-9856 [https://bugs.python.org/issue?@action=redirect&bpo=9856]).

The unicode_internal codec has been deprecated because of the PEP 393 [https://peps.python.org/pep-0393/], use UTF-8, UTF-16 (utf-16-le or utf-16-be), or UTF-32 (utf-32-le or utf-32-be)

ftplib.FTP.nlst() and ftplib.FTP.dir(): use ftplib.FTP.mlsd()

platform.popen(): use the subprocess module. Check especially the 이전 함수를 subprocess 모듈로 교체하기 section (bpo-11377 [https://bugs.python.org/issue?@action=redirect&bpo=11377]).

bpo-13374 [https://bugs.python.org/issue?@action=redirect&bpo=13374]: The Windows bytes API has been deprecated in the os module. Use Unicode filenames, instead of bytes filenames, to not depend on the ANSI code page anymore and to support any filename.

bpo-13988 [https://bugs.python.org/issue?@action=redirect&bpo=13988]: The xml.etree.cElementTree module is deprecated. The accelerator is used automatically whenever available.

The behaviour of time.clock() depends on the platform: use the new time.perf_counter() or time.process_time() function instead, depending on your requirements, to have a well defined behaviour.

The os.stat_float_times() function is deprecated.

abc module:

abc.abstractproperty has been deprecated, use property with abc.abstractmethod() instead.

abc.abstractclassmethod has been deprecated, use classmethod with abc.abstractmethod() instead.

abc.abstractstaticmethod has been deprecated, use staticmethod with abc.abstractmethod() instead.

importlib package:

importlib.abc.SourceLoader.path_mtime() is now deprecated in favour of importlib.abc.SourceLoader.path_stats() as bytecode files now store both the modification time and size of the source file the bytecode file was compiled from.

Deprecated functions and types of the C API

The Py_UNICODE has been deprecated by PEP 393 [https://peps.python.org/pep-0393/] and will be removed in Python 4. All functions using this type are deprecated:

Unicode functions and methods using Py_UNICODE and Py_UNICODE* types:

PyUnicode_FromUnicode: use PyUnicode_FromWideChar() or PyUnicode_FromKindAndData()

PyUnicode_AS_UNICODE, PyUnicode_AsUnicode(), PyUnicode_AsUnicodeAndSize(): use PyUnicode_AsWideCharString()

PyUnicode_AS_DATA: use PyUnicode_DATA with PyUnicode_READ and PyUnicode_WRITE

PyUnicode_GET_SIZE, PyUnicode_GetSize(): use PyUnicode_GET_LENGTH or PyUnicode_GetLength()

PyUnicode_GET_DATA_SIZE: use PyUnicode_GET_LENGTH(str) * PyUnicode_KIND(str) (only work on ready strings)

PyUnicode_AsUnicodeCopy(): use PyUnicode_AsUCS4Copy() or PyUnicode_AsWideCharString()

PyUnicode_GetMax()

Functions and macros manipulating Py_UNICODE* strings:

Py_UNICODE_strlen(): use PyUnicode_GetLength() or PyUnicode_GET_LENGTH

Py_UNICODE_strcat(): use PyUnicode_CopyCharacters() or PyUnicode_FromFormat()

Py_UNICODE_strcpy(), Py_UNICODE_strncpy(), Py_UNICODE_COPY(): use PyUnicode_CopyCharacters() or PyUnicode_Substring()

Py_UNICODE_strcmp(): use PyUnicode_Compare()

Py_UNICODE_strncmp(): use PyUnicode_Tailmatch()

Py_UNICODE_strchr(), Py_UNICODE_strrchr(): use PyUnicode_FindChar()

Py_UNICODE_FILL(): use PyUnicode_Fill()

Py_UNICODE_MATCH

Encoders:

PyUnicode_Encode(): use PyUnicode_AsEncodedObject()

PyUnicode_EncodeUTF7()

PyUnicode_EncodeUTF8(): use PyUnicode_AsUTF8() or PyUnicode_AsUTF8String()

PyUnicode_EncodeUTF32()

PyUnicode_EncodeUTF16()

PyUnicode_EncodeUnicodeEscape() use PyUnicode_AsUnicodeEscapeString()

PyUnicode_EncodeRawUnicodeEscape() use PyUnicode_AsRawUnicodeEscapeString()

PyUnicode_EncodeLatin1(): use PyUnicode_AsLatin1String()

PyUnicode_EncodeASCII(): use PyUnicode_AsASCIIString()

PyUnicode_EncodeCharmap()

PyUnicode_TranslateCharmap()

PyUnicode_EncodeMBCS(): use PyUnicode_AsMBCSString() or PyUnicode_EncodeCodePage() (with CP_ACP code_page)

PyUnicode_EncodeDecimal(), PyUnicode_TransformDecimalToASCII()

Deprecated features

The array module’s 'u' format code is now deprecated and will be removed in Python 4 together with the rest of the (Py_UNICODE) API.

Porting to Python 3.3

This section lists previously described changes and other bugfixes that may require changes to your code.

Porting Python code

Hash randomization is enabled by default. Set the PYTHONHASHSEED environment variable to 0 to disable hash randomization. See also the object.__hash__() method.

bpo-12326 [https://bugs.python.org/issue?@action=redirect&bpo=12326]: On Linux, sys.platform doesn’t contain the major version anymore. It is now always ‘linux’, instead of ‘linux2’ or ‘linux3’ depending on the Linux version used to build Python. Replace sys.platform == ‘linux2’ with sys.platform.startswith(‘linux’), or directly sys.platform == ‘linux’ if you don’t need to support older Python versions.

bpo-13847 [https://bugs.python.org/issue?@action=redirect&bpo=13847], bpo-14180 [https://bugs.python.org/issue?@action=redirect&bpo=14180]: time and datetime: OverflowError is now raised instead of ValueError if a timestamp is out of range. OSError is now raised if C functions gmtime() or localtime() failed.

The default finders used by import now utilize a cache of what is contained within a specific directory. If you create a Python source file or sourceless bytecode file, make sure to call importlib.invalidate_caches() to clear out the cache for the finders to notice the new file.

ImportError now uses the full name of the module that was attempted to be imported. Doctests that check ImportErrors’ message will need to be updated to use the full name of the module instead of just the tail of the name.

The index argument to __import__() now defaults to 0 instead of -1 and no longer support negative values. It was an oversight when PEP 328 [https://peps.python.org/pep-0328/] was implemented that the default value remained -1. If you need to continue to perform a relative import followed by an absolute import, then perform the relative import using an index of 1, followed by another import using an index of 0. It is preferred, though, that you use importlib.import_module() rather than call __import__() directly.

__import__() no longer allows one to use an index value other than 0 for top-level modules. E.g. __import__('sys', level=1) is now an error.

Because sys.meta_path and sys.path_hooks now have finders on them by default, you will most likely want to use list.insert() instead of list.append() to add to those lists.

Because None is now inserted into sys.path_importer_cache, if you are clearing out entries in the dictionary of paths that do not have a finder, you will need to remove keys paired with values of None and imp.NullImporter to be backwards-compatible. This will lead to extra overhead on older versions of Python that re-insert None into sys.path_importer_cache where it represents the use of implicit finders, but semantically it should not change anything.

importlib.abc.Finder no longer specifies a find_module() abstract method that must be implemented. If you were relying on subclasses to implement that method, make sure to check for the method’s existence first. You will probably want to check for find_loader() first, though, in the case of working with path entry finders.

pkgutil has been converted to use importlib internally. This eliminates many edge cases where the old behaviour of the PEP 302 [https://peps.python.org/pep-0302/] import emulation failed to match the behaviour of the real import system. The import emulation itself is still present, but is now deprecated. The pkgutil.iter_importers() and pkgutil.walk_packages() functions special case the standard import hooks so they are still supported even though they do not provide the non-standard iter_modules() method.

A longstanding RFC-compliance bug (bpo-1079 [https://bugs.python.org/issue?@action=redirect&bpo=1079]) in the parsing done by email.header.decode_header() has been fixed. Code that uses the standard idiom to convert encoded headers into unicode (str(make_header(decode_header(h))) will see no change, but code that looks at the individual tuples returned by decode_header will see that whitespace that precedes or follows ASCII sections is now included in the ASCII section. Code that builds headers using make_header should also continue to work without change, since make_header continues to add whitespace between ASCII and non-ASCII sections if it is not already present in the input strings.

email.utils.formataddr() now does the correct content transfer encoding when passed non-ASCII display names. Any code that depended on the previous buggy behavior that preserved the non-ASCII unicode in the formatted output string will need to be changed (bpo-1690608 [https://bugs.python.org/issue?@action=redirect&bpo=1690608]).

poplib.POP3.quit() may now raise protocol errors like all other poplib methods. Code that assumes quit does not raise poplib.error_proto errors may need to be changed if errors on quit are encountered by a particular application (bpo-11291 [https://bugs.python.org/issue?@action=redirect&bpo=11291]).

The strict argument to email.parser.Parser, deprecated since Python 2.4, has finally been removed.

The deprecated method unittest.TestCase.assertSameElements has been removed.

The deprecated variable time.accept2dyear has been removed.

The deprecated Context._clamp attribute has been removed from the decimal module. It was previously replaced by the public attribute clamp. (See bpo-8540 [https://bugs.python.org/issue?@action=redirect&bpo=8540].)

The undocumented internal helper class SSLFakeFile has been removed from smtplib, since its functionality has long been provided directly by socket.socket.makefile().

Passing a negative value to time.sleep() on Windows now raises an error instead of sleeping forever. It has always raised an error on posix.

The ast.__version__ constant has been removed. If you need to make decisions affected by the AST version, use sys.version_info to make the decision.

Code that used to work around the fact that the threading module used factory functions by subclassing the private classes will need to change to subclass the now-public classes.

The undocumented debugging machinery in the threading module has been removed, simplifying the code. This should have no effect on production code, but is mentioned here in case any application debug frameworks were interacting with it (bpo-13550 [https://bugs.python.org/issue?@action=redirect&bpo=13550]).

Porting C code

In the course of changes to the buffer API the undocumented smalltable member of the Py_buffer structure has been removed and the layout of the PyMemoryViewObject has changed.

All extensions relying on the relevant parts in memoryobject.h or object.h must be rebuilt.

Due to PEP 393, the Py_UNICODE type and all functions using this type are deprecated (but will stay available for at least five years). If you were using low-level Unicode APIs to construct and access unicode objects and you want to benefit of the memory footprint reduction provided by PEP 393 [https://peps.python.org/pep-0393/], you have to convert your code to the new Unicode API.

However, if you only have been using high-level functions such as PyUnicode_Concat(), PyUnicode_Join() or PyUnicode_FromFormat(), your code will automatically take advantage of the new unicode representations.

PyImport_GetMagicNumber() now returns -1 upon failure.

As a negative value for the level argument to __import__() is no longer valid, the same now holds for PyImport_ImportModuleLevel(). This also means that the value of level used by PyImport_ImportModuleEx() is now 0 instead of -1.

Building C extensions

The range of possible file names for C extensions has been narrowed. Very rarely used spellings have been suppressed: under POSIX, files named xxxmodule.so, xxxmodule.abi3.so and xxxmodule.cpython-*.so are no longer recognized as implementing the xxx module. If you had been generating such files, you have to switch to the other spellings (i.e., remove the module string from the file names).

(implemented in bpo-14040 [https://bugs.python.org/issue?@action=redirect&bpo=14040].)

Command Line Switch Changes

The -Q command-line flag and related artifacts have been removed. Code checking sys.flags.division_warning will need updating.

(bpo-10998 [https://bugs.python.org/issue?@action=redirect&bpo=10998], contributed by Éric Araujo.)

When python is started with -S, import site will no longer add site-specific paths to the module search paths. In previous versions, it did.

(bpo-11591 [https://bugs.python.org/issue?@action=redirect&bpo=11591], contributed by Carl Meyer with editions by Éric Araujo.)

What’s New In Python 3.2

Author:

Raymond Hettinger

This article explains the new features in Python 3.2 as compared to 3.1. Python 3.2 was released on February 20, 2011. It focuses on a few highlights and gives a few examples. For full details, see the Misc/NEWS [https://github.com/python/cpython/blob/076ca6c3c8df3030307e548d9be792ce3c1c6eea/Misc/NEWS] file.

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PEP 392 [https://peps.python.org/pep-0392/] - Python 3.2 Release Schedule

PEP 384: Defining a Stable ABI

In the past, extension modules built for one Python version were often not usable with other Python versions. Particularly on Windows, every feature release of Python required rebuilding all extension modules that one wanted to use. This requirement was the result of the free access to Python interpreter internals that extension modules could use.

With Python 3.2, an alternative approach becomes available: extension modules which restrict themselves to a limited API (by defining Py_LIMITED_API) cannot use many of the internals, but are constrained to a set of API functions that are promised to be stable for several releases. As a consequence, extension modules built for 3.2 in that mode will also work with 3.3, 3.4, and so on. Extension modules that make use of details of memory structures can still be built, but will need to be recompiled for every feature release.

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PEP 384 [https://peps.python.org/pep-0384/] - Defining a Stable ABI

PEP written by Martin von Löwis.

PEP 389: Argparse Command Line Parsing Module

A new module for command line parsing, argparse, was introduced to overcome the limitations of optparse which did not provide support for positional arguments (not just options), subcommands, required options and other common patterns of specifying and validating options.

This module has already had widespread success in the community as a third-party module. Being more fully featured than its predecessor, the argparse module is now the preferred module for command-line processing. The older module is still being kept available because of the substantial amount of legacy code that depends on it.

Here’s an annotated example parser showing features like limiting results to a set of choices, specifying a metavar in the help screen, validating that one or more positional arguments is present, and making a required option:

import argparse
parser = argparse.ArgumentParser(
            description = 'Manage servers',         # main description for help
            epilog = 'Tested on Solaris and Linux') # displayed after help
parser.add_argument('action',                       # argument name
            choices = ['deploy', 'start', 'stop'],  # three allowed values
            help = 'action on each target')         # help msg
parser.add_argument('targets',
            metavar = 'HOSTNAME',                   # var name used in help msg
            nargs = '+',                            # require one or more targets
            help = 'url for target machines')       # help msg explanation
parser.add_argument('-u', '--user',                 # -u or --user option
            required = True,                        # make it a required argument
            help = 'login as user')

Example of calling the parser on a command string:

>>> cmd = 'deploy sneezy.example.com sleepy.example.com -u skycaptain'
>>> result = parser.parse_args(cmd.split())
>>> result.action
'deploy'
>>> result.targets
['sneezy.example.com', 'sleepy.example.com']
>>> result.user
'skycaptain'

Example of the parser’s automatically generated help:

>>> parser.parse_args('-h'.split())

usage: manage_cloud.py [-h] -u USER
                       {deploy,start,stop} HOSTNAME [HOSTNAME ...]

Manage servers

positional arguments:
  {deploy,start,stop}   action on each target
  HOSTNAME              url for target machines

optional arguments:
  -h, --help            show this help message and exit
  -u USER, --user USER  login as user

Tested on Solaris and Linux

An especially nice argparse feature is the ability to define subparsers, each with their own argument patterns and help displays:

import argparse
parser = argparse.ArgumentParser(prog='HELM')
subparsers = parser.add_subparsers()

parser_l = subparsers.add_parser('launch', help='Launch Control')   # first subgroup
parser_l.add_argument('-m', '--missiles', action='store_true')
parser_l.add_argument('-t', '--torpedos', action='store_true')

parser_m = subparsers.add_parser('move', help='Move Vessel',        # second subgroup
                                 aliases=('steer', 'turn'))         # equivalent names
parser_m.add_argument('-c', '--course', type=int, required=True)
parser_m.add_argument('-s', '--speed', type=int, default=0)

$ ./helm.py --help                         # top level help (launch and move)
$ ./helm.py launch --help                  # help for launch options
$ ./helm.py launch --missiles              # set missiles=True and torpedos=False
$ ./helm.py steer --course 180 --speed 5   # set movement parameters

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PEP 389 [https://peps.python.org/pep-0389/] - New Command Line Parsing Module

PEP written by Steven Bethard.

Upgrading optparse code for details on the differences from optparse.

PEP 391: Dictionary Based Configuration for Logging

The logging module provided two kinds of configuration, one style with function calls for each option or another style driven by an external file saved in a configparser format. Those options did not provide the flexibility to create configurations from JSON or YAML files, nor did they support incremental configuration, which is needed for specifying logger options from a command line.

To support a more flexible style, the module now offers logging.config.dictConfig() for specifying logging configuration with plain Python dictionaries. The configuration options include formatters, handlers, filters, and loggers. Here’s a working example of a configuration dictionary:

{"version": 1,
 "formatters": {"brief": {"format": "%(levelname)-8s: %(name)-15s: %(message)s"},
                "full": {"format": "%(asctime)s %(name)-15s %(levelname)-8s %(message)s"}
                },
 "handlers": {"console": {
                   "class": "logging.StreamHandler",
                   "formatter": "brief",
                   "level": "INFO",
                   "stream": "ext://sys.stdout"},
              "console_priority": {
                   "class": "logging.StreamHandler",
                   "formatter": "full",
                   "level": "ERROR",
                   "stream": "ext://sys.stderr"}
              },
 "root": {"level": "DEBUG", "handlers": ["console", "console_priority"]}}

If that dictionary is stored in a file called conf.json, it can be loaded and called with code like this:

>>> import json, logging.config
>>> with open('conf.json') as f:
...     conf = json.load(f)
...
>>> logging.config.dictConfig(conf)
>>> logging.info("Transaction completed normally")
INFO    : root           : Transaction completed normally
>>> logging.critical("Abnormal termination")
2011-02-17 11:14:36,694 root            CRITICAL Abnormal termination

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PEP 391 [https://peps.python.org/pep-0391/] - Dictionary Based Configuration for Logging

PEP written by Vinay Sajip.

PEP 3148: The concurrent.futures module

Code for creating and managing concurrency is being collected in a new top-level namespace, concurrent. Its first member is a futures package which provides a uniform high-level interface for managing threads and processes.

The design for concurrent.futures was inspired by the java.util.concurrent package. In that model, a running call and its result are represented by a Future object that abstracts features common to threads, processes, and remote procedure calls. That object supports status checks (running or done), timeouts, cancellations, adding callbacks, and access to results or exceptions.

The primary offering of the new module is a pair of executor classes for launching and managing calls. The goal of the executors is to make it easier to use existing tools for making parallel calls. They save the effort needed to setup a pool of resources, launch the calls, create a results queue, add time-out handling, and limit the total number of threads, processes, or remote procedure calls.

Ideally, each application should share a single executor across multiple components so that process and thread limits can be centrally managed. This solves the design challenge that arises when each component has its own competing strategy for resource management.

Both classes share a common interface with three methods: submit() for scheduling a callable and returning a Future object; map() for scheduling many asynchronous calls at a time, and shutdown() for freeing resources. The class is a context manager and can be used in a with statement to assure that resources are automatically released when currently pending futures are done executing.

A simple of example of ThreadPoolExecutor is a launch of four parallel threads for copying files:

import concurrent.futures, shutil
with concurrent.futures.ThreadPoolExecutor(max_workers=4) as e:
    e.submit(shutil.copy, 'src1.txt', 'dest1.txt')
    e.submit(shutil.copy, 'src2.txt', 'dest2.txt')
    e.submit(shutil.copy, 'src3.txt', 'dest3.txt')
    e.submit(shutil.copy, 'src3.txt', 'dest4.txt')

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PEP 3148 [https://peps.python.org/pep-3148/] - Futures – Execute Computations Asynchronously

PEP written by Brian Quinlan.

Code for Threaded Parallel URL reads, an example using threads to fetch multiple web pages in parallel.

Code for computing prime numbers in parallel, an example demonstrating ProcessPoolExecutor.

PEP 3147: PYC Repository Directories

Python’s scheme for caching bytecode in .pyc files did not work well in environments with multiple Python interpreters. If one interpreter encountered a cached file created by another interpreter, it would recompile the source and overwrite the cached file, thus losing the benefits of caching.

The issue of “pyc fights” has become more pronounced as it has become commonplace for Linux distributions to ship with multiple versions of Python. These conflicts also arise with CPython alternatives such as Unladen Swallow.

To solve this problem, Python’s import machinery has been extended to use distinct filenames for each interpreter. Instead of Python 3.2 and Python 3.3 and Unladen Swallow each competing for a file called “mymodule.pyc”, they will now look for “mymodule.cpython-32.pyc”, “mymodule.cpython-33.pyc”, and “mymodule.unladen10.pyc”. And to prevent all of these new files from cluttering source directories, the pyc files are now collected in a “__pycache__” directory stored under the package directory.

Aside from the filenames and target directories, the new scheme has a few aspects that are visible to the programmer:

Imported modules now have a __cached__ attribute which stores the name of the actual file that was imported:

>>> import collections
>>> collections.__cached__
'c:/py32/lib/__pycache__/collections.cpython-32.pyc'

The tag that is unique to each interpreter is accessible from the imp module:

>>> import imp
>>> imp.get_tag()
'cpython-32'

Scripts that try to deduce source filename from the imported file now need to be smarter. It is no longer sufficient to simply strip the “c” from a “.pyc” filename. Instead, use the new functions in the imp module:

>>> imp.source_from_cache('c:/py32/lib/__pycache__/collections.cpython-32.pyc')
'c:/py32/lib/collections.py'
>>> imp.cache_from_source('c:/py32/lib/collections.py')
'c:/py32/lib/__pycache__/collections.cpython-32.pyc'

The py_compile and compileall modules have been updated to reflect the new naming convention and target directory. The command-line invocation of compileall has new options: -i for specifying a list of files and directories to compile and -b which causes bytecode files to be written to their legacy location rather than __pycache__.

The importlib.abc module has been updated with new abstract base classes for loading bytecode files. The obsolete ABCs, PyLoader and PyPycLoader, have been deprecated (instructions on how to stay Python 3.1 compatible are included with the documentation).

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PEP 3147 [https://peps.python.org/pep-3147/] - PYC Repository Directories

PEP written by Barry Warsaw.

PEP 3149: ABI Version Tagged .so Files

The PYC repository directory allows multiple bytecode cache files to be co-located. This PEP implements a similar mechanism for shared object files by giving them a common directory and distinct names for each version.

The common directory is “pyshared” and the file names are made distinct by identifying the Python implementation (such as CPython, PyPy, Jython, etc.), the major and minor version numbers, and optional build flags (such as “d” for debug, “m” for pymalloc, “u” for wide-unicode). For an arbitrary package “foo”, you may see these files when the distribution package is installed:

/usr/share/pyshared/foo.cpython-32m.so
/usr/share/pyshared/foo.cpython-33md.so

In Python itself, the tags are accessible from functions in the sysconfig module:

>>> import sysconfig
>>> sysconfig.get_config_var('SOABI')       # find the version tag
'cpython-32mu'
>>> sysconfig.get_config_var('EXT_SUFFIX')  # find the full filename extension
'.cpython-32mu.so'

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PEP 3149 [https://peps.python.org/pep-3149/] - ABI Version Tagged .so Files

PEP written by Barry Warsaw.

PEP 3333: Python Web Server Gateway Interface v1.0.1

This informational PEP clarifies how bytes/text issues are to be handled by the WSGI protocol. The challenge is that string handling in Python 3 is most conveniently handled with the str type even though the HTTP protocol is itself bytes oriented.

The PEP differentiates so-called native strings that are used for request/response headers and metadata versus byte strings which are used for the bodies of requests and responses.

The native strings are always of type str but are restricted to code points between U+0000 through U+00FF which are translatable to bytes using Latin-1 encoding. These strings are used for the keys and values in the environment dictionary and for response headers and statuses in the start_response() function. They must follow RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html] with respect to encoding. That is, they must either be ISO-8859-1 characters or use RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] MIME encoding.

For developers porting WSGI applications from Python 2, here are the salient points:

If the app already used strings for headers in Python 2, no change is needed.

If instead, the app encoded output headers or decoded input headers, then the headers will need to be re-encoded to Latin-1. For example, an output header encoded in utf-8 was using h.encode('utf-8') now needs to convert from bytes to native strings using h.encode('utf-8').decode('latin-1').

Values yielded by an application or sent using the write() method must be byte strings. The start_response() function and environ must use native strings. The two cannot be mixed.

For server implementers writing CGI-to-WSGI pathways or other CGI-style protocols, the users must to be able access the environment using native strings even though the underlying platform may have a different convention. To bridge this gap, the wsgiref module has a new function, wsgiref.handlers.read_environ() for transcoding CGI variables from os.environ into native strings and returning a new dictionary.

더 보기

PEP 3333 [https://peps.python.org/pep-3333/] - Python Web Server Gateway Interface v1.0.1

PEP written by Phillip Eby.

Other Language Changes

Some smaller changes made to the core Python language are:

String formatting for format() and str.format() gained new capabilities for the format character #. Previously, for integers in binary, octal, or hexadecimal, it caused the output to be prefixed with ‘0b’, ‘0o’, or ‘0x’ respectively. Now it can also handle floats, complex, and Decimal, causing the output to always have a decimal point even when no digits follow it.

>>> format(20, '#o')
'0o24'
>>> format(12.34, '#5.0f')
'  12.'

(Suggested by Mark Dickinson and implemented by Eric Smith in bpo-7094 [https://bugs.python.org/issue?@action=redirect&bpo=7094].)

There is also a new str.format_map() method that extends the capabilities of the existing str.format() method by accepting arbitrary mapping objects. This new method makes it possible to use string formatting with any of Python’s many dictionary-like objects such as defaultdict, Shelf, ConfigParser, or dbm. It is also useful with custom dict subclasses that normalize keys before look-up or that supply a __missing__() method for unknown keys:

>>> import shelve
>>> d = shelve.open('tmp.shl')
>>> 'The {project_name} status is {status} as of {date}'.format_map(d)
'The testing project status is green as of February 15, 2011'

>>> class LowerCasedDict(dict):
...     def __getitem__(self, key):
...         return dict.__getitem__(self, key.lower())
...
>>> lcd = LowerCasedDict(part='widgets', quantity=10)
>>> 'There are {QUANTITY} {Part} in stock'.format_map(lcd)
'There are 10 widgets in stock'

>>> class PlaceholderDict(dict):
...     def __missing__(self, key):
...         return '<{}>'.format(key)
...
>>> 'Hello {name}, welcome to {location}'.format_map(PlaceholderDict())
'Hello <name>, welcome to <location>'

(Suggested by Raymond Hettinger and implemented by Eric Smith in bpo-6081 [https://bugs.python.org/issue?@action=redirect&bpo=6081].)

The interpreter can now be started with a quiet option, -q, to prevent the copyright and version information from being displayed in the interactive mode. The option can be introspected using the sys.flags attribute:

$ python -q
>>> sys.flags
sys.flags(debug=0, division_warning=0, inspect=0, interactive=0,
optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0,
ignore_environment=0, verbose=0, bytes_warning=0, quiet=1)

(Contributed by Marcin Wojdyr in bpo-1772833 [https://bugs.python.org/issue?@action=redirect&bpo=1772833]).

The hasattr() function works by calling getattr() and detecting whether an exception is raised. This technique allows it to detect methods created dynamically by __getattr__() or __getattribute__() which would otherwise be absent from the class dictionary. Formerly, hasattr would catch any exception, possibly masking genuine errors. Now, hasattr has been tightened to only catch AttributeError and let other exceptions pass through:

>>> class A:
...     @property
...     def f(self):
...         return 1 // 0
...
>>> a = A()
>>> hasattr(a, 'f')
Traceback (most recent call last):
  ...
ZeroDivisionError: integer division or modulo by zero

(Discovered by Yury Selivanov and fixed by Benjamin Peterson; bpo-9666 [https://bugs.python.org/issue?@action=redirect&bpo=9666].)

The str() of a float or complex number is now the same as its repr(). Previously, the str() form was shorter but that just caused confusion and is no longer needed now that the shortest possible repr() is displayed by default:

>>> import math
>>> repr(math.pi)
'3.141592653589793'
>>> str(math.pi)
'3.141592653589793'

(Proposed and implemented by Mark Dickinson; bpo-9337 [https://bugs.python.org/issue?@action=redirect&bpo=9337].)

memoryview objects now have a release() method and they also now support the context management protocol. This allows timely release of any resources that were acquired when requesting a buffer from the original object.

>>> with memoryview(b'abcdefgh') as v:
...     print(v.tolist())
[97, 98, 99, 100, 101, 102, 103, 104]

(Added by Antoine Pitrou; bpo-9757 [https://bugs.python.org/issue?@action=redirect&bpo=9757].)

Previously it was illegal to delete a name from the local namespace if it occurs as a free variable in a nested block:

def outer(x):
    def inner():
        return x
    inner()
    del x

This is now allowed. Remember that the target of an except clause is cleared, so this code which used to work with Python 2.6, raised a SyntaxError with Python 3.1 and now works again:

def f():
    def print_error():
        print(e)
    try:
        something
    except Exception as e:
        print_error()
        # implicit "del e" here

(See bpo-4617 [https://bugs.python.org/issue?@action=redirect&bpo=4617].)

Struct sequence types are now subclasses of tuple. This means that C structures like those returned by os.stat(), time.gmtime(), and sys.version_info now work like a named tuple and now work with functions and methods that expect a tuple as an argument. This is a big step forward in making the C structures as flexible as their pure Python counterparts:

>>> import sys
>>> isinstance(sys.version_info, tuple)
True
>>> 'Version %d.%d.%d %s(%d)' % sys.version_info
'Version 3.2.0 final(0)'

(Suggested by Arfrever Frehtes Taifersar Arahesis and implemented by Benjamin Peterson in bpo-8413 [https://bugs.python.org/issue?@action=redirect&bpo=8413].)

Warnings are now easier to control using the PYTHONWARNINGS environment variable as an alternative to using -W at the command line:

$ export PYTHONWARNINGS='ignore::RuntimeWarning::,once::UnicodeWarning::'

(Suggested by Barry Warsaw and implemented by Philip Jenvey in bpo-7301 [https://bugs.python.org/issue?@action=redirect&bpo=7301].)

A new warning category, ResourceWarning, has been added. It is emitted when potential issues with resource consumption or cleanup are detected. It is silenced by default in normal release builds but can be enabled through the means provided by the warnings module, or on the command line.

A ResourceWarning is issued at interpreter shutdown if the gc.garbage list isn’t empty, and if gc.DEBUG_UNCOLLECTABLE is set, all uncollectable objects are printed. This is meant to make the programmer aware that their code contains object finalization issues.

A ResourceWarning is also issued when a file object is destroyed without having been explicitly closed. While the deallocator for such object ensures it closes the underlying operating system resource (usually, a file descriptor), the delay in deallocating the object could produce various issues, especially under Windows. Here is an example of enabling the warning from the command line:

$ python -q -Wdefault
>>> f = open("foo", "wb")
>>> del f
__main__:1: ResourceWarning: unclosed file <_io.BufferedWriter name='foo'>

(Added by Antoine Pitrou and Georg Brandl in bpo-10093 [https://bugs.python.org/issue?@action=redirect&bpo=10093] and bpo-477863 [https://bugs.python.org/issue?@action=redirect&bpo=477863].)

range objects now support index and count methods. This is part of an effort to make more objects fully implement the collections.Sequence abstract base class. As a result, the language will have a more uniform API. In addition, range objects now support slicing and negative indices, even with values larger than sys.maxsize. This makes range more interoperable with lists:

>>> range(0, 100, 2).count(10)
1
>>> range(0, 100, 2).index(10)
5
>>> range(0, 100, 2)[5]
10
>>> range(0, 100, 2)[0:5]
range(0, 10, 2)

(Contributed by Daniel Stutzbach in bpo-9213 [https://bugs.python.org/issue?@action=redirect&bpo=9213], by Alexander Belopolsky in bpo-2690 [https://bugs.python.org/issue?@action=redirect&bpo=2690], and by Nick Coghlan in bpo-10889 [https://bugs.python.org/issue?@action=redirect&bpo=10889].)

The callable() builtin function from Py2.x was resurrected. It provides a concise, readable alternative to using an abstract base class in an expression like isinstance(x, collections.Callable):

>>> callable(max)
True
>>> callable(20)
False

(See bpo-10518 [https://bugs.python.org/issue?@action=redirect&bpo=10518].)

Python’s import mechanism can now load modules installed in directories with non-ASCII characters in the path name. This solved an aggravating problem with home directories for users with non-ASCII characters in their usernames.

(Required extensive work by Victor Stinner in bpo-9425 [https://bugs.python.org/issue?@action=redirect&bpo=9425].)

New, Improved, and Deprecated Modules

Python’s standard library has undergone significant maintenance efforts and quality improvements.

The biggest news for Python 3.2 is that the email package, mailbox module, and nntplib modules now work correctly with the bytes/text model in Python 3. For the first time, there is correct handling of messages with mixed encodings.

Throughout the standard library, there has been more careful attention to encodings and text versus bytes issues. In particular, interactions with the operating system are now better able to exchange non-ASCII data using the Windows MBCS encoding, locale-aware encodings, or UTF-8.

Another significant win is the addition of substantially better support for SSL connections and security certificates.

In addition, more classes now implement a context manager to support convenient and reliable resource clean-up using a with statement.

email

The usability of the email package in Python 3 has been mostly fixed by the extensive efforts of R. David Murray. The problem was that emails are typically read and stored in the form of bytes rather than str text, and they may contain multiple encodings within a single email. So, the email package had to be extended to parse and generate email messages in bytes format.

New functions message_from_bytes() and message_from_binary_file(), and new classes BytesFeedParser and BytesParser allow binary message data to be parsed into model objects.

Given bytes input to the model, get_payload() will by default decode a message body that has a Content-Transfer-Encoding of 8bit using the charset specified in the MIME headers and return the resulting string.

Given bytes input to the model, Generator will convert message bodies that have a Content-Transfer-Encoding of 8bit to instead have a 7bit Content-Transfer-Encoding.

Headers with unencoded non-ASCII bytes are deemed to be RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html]-encoded using the unknown-8bit character set.

A new class BytesGenerator produces bytes as output, preserving any unchanged non-ASCII data that was present in the input used to build the model, including message bodies with a Content-Transfer-Encoding of 8bit.

The smtplib SMTP class now accepts a byte string for the msg argument to the sendmail() method, and a new method, send_message() accepts a Message object and can optionally obtain the from_addr and to_addrs addresses directly from the object.

(Proposed and implemented by R. David Murray, bpo-4661 [https://bugs.python.org/issue?@action=redirect&bpo=4661] and bpo-10321 [https://bugs.python.org/issue?@action=redirect&bpo=10321].)

elementtree

The xml.etree.ElementTree package and its xml.etree.cElementTree counterpart have been updated to version 1.3.

Several new and useful functions and methods have been added:

xml.etree.ElementTree.fromstringlist() which builds an XML document from a sequence of fragments

xml.etree.ElementTree.register_namespace() for registering a global namespace prefix

xml.etree.ElementTree.tostringlist() for string representation including all sublists

xml.etree.ElementTree.Element.extend() for appending a sequence of zero or more elements

xml.etree.ElementTree.Element.iterfind() searches an element and subelements

xml.etree.ElementTree.Element.itertext() creates a text iterator over an element and its subelements

xml.etree.ElementTree.TreeBuilder.end() closes the current element

xml.etree.ElementTree.TreeBuilder.doctype() handles a doctype declaration

Two methods have been deprecated:

xml.etree.ElementTree.getchildren() use list(elem) instead.

xml.etree.ElementTree.getiterator() use Element.iter instead.

For details of the update, see Introducing ElementTree [https://web.archive.org/web/20200703234532/http://effbot.org/zone/elementtree-13-intro.htm] on Fredrik Lundh’s website.

(Contributed by Florent Xicluna and Fredrik Lundh, bpo-6472 [https://bugs.python.org/issue?@action=redirect&bpo=6472].)

functools

The functools module includes a new decorator for caching function calls. functools.lru_cache() can save repeated queries to an external resource whenever the results are expected to be the same.

For example, adding a caching decorator to a database query function can save database accesses for popular searches:

>>> import functools
>>> @functools.lru_cache(maxsize=300)
... def get_phone_number(name):
...     c = conn.cursor()
...     c.execute('SELECT phonenumber FROM phonelist WHERE name=?', (name,))
...     return c.fetchone()[0]

>>> for name in user_requests:
...     get_phone_number(name)        # cached lookup

To help with choosing an effective cache size, the wrapped function is instrumented for tracking cache statistics:

>>> get_phone_number.cache_info()
CacheInfo(hits=4805, misses=980, maxsize=300, currsize=300)

If the phonelist table gets updated, the outdated contents of the cache can be cleared with:

>>> get_phone_number.cache_clear()

(Contributed by Raymond Hettinger and incorporating design ideas from Jim Baker, Miki Tebeka, and Nick Coghlan; see recipe 498245 [https://code.activestate.com/recipes/498245-lru-and-lfu-cache-decorators/], recipe 577479 [https://code.activestate.com/recipes/577479-simple-caching-decorator/], bpo-10586 [https://bugs.python.org/issue?@action=redirect&bpo=10586], and bpo-10593 [https://bugs.python.org/issue?@action=redirect&bpo=10593].)

The functools.wraps() decorator now adds a __wrapped__ attribute pointing to the original callable function. This allows wrapped functions to be introspected. It also copies __annotations__ if defined. And now it also gracefully skips over missing attributes such as __doc__ which might not be defined for the wrapped callable.

In the above example, the cache can be removed by recovering the original function:

>>> get_phone_number = get_phone_number.__wrapped__    # uncached function

(By Nick Coghlan and Terrence Cole; bpo-9567 [https://bugs.python.org/issue?@action=redirect&bpo=9567], bpo-3445 [https://bugs.python.org/issue?@action=redirect&bpo=3445], and bpo-8814 [https://bugs.python.org/issue?@action=redirect&bpo=8814].)

To help write classes with rich comparison methods, a new decorator functools.total_ordering() will use existing equality and inequality methods to fill in the remaining methods.

For example, supplying __eq__ and __lt__ will enable total_ordering() to fill-in __le__, __gt__ and __ge__:

@total_ordering
class Student:
    def __eq__(self, other):
        return ((self.lastname.lower(), self.firstname.lower()) ==
                (other.lastname.lower(), other.firstname.lower()))

    def __lt__(self, other):
        return ((self.lastname.lower(), self.firstname.lower()) <
                (other.lastname.lower(), other.firstname.lower()))

With the total_ordering decorator, the remaining comparison methods are filled in automatically.

(Contributed by Raymond Hettinger.)

To aid in porting programs from Python 2, the functools.cmp_to_key() function converts an old-style comparison function to modern key function:

>>> # locale-aware sort order
>>> sorted(iterable, key=cmp_to_key(locale.strcoll))

For sorting examples and a brief sorting tutorial, see the Sorting HowTo [https://wiki.python.org/moin/HowTo/Sorting/] tutorial.

(Contributed by Raymond Hettinger.)

itertools

The itertools module has a new accumulate() function modeled on APL’s scan operator and Numpy’s accumulate function:

>>> from itertools import accumulate
>>> list(accumulate([8, 2, 50]))
[8, 10, 60]

>>> prob_dist = [0.1, 0.4, 0.2, 0.3]
>>> list(accumulate(prob_dist))      # cumulative probability distribution
[0.1, 0.5, 0.7, 1.0]

For an example using accumulate(), see the examples for the random module.

(Contributed by Raymond Hettinger and incorporating design suggestions from Mark Dickinson.)

collections

The collections.Counter class now has two forms of in-place subtraction, the existing -= operator for saturating subtraction [https://en.wikipedia.org/wiki/Saturation_arithmetic] and the new subtract() method for regular subtraction. The former is suitable for multisets [https://en.wikipedia.org/wiki/Multiset] which only have positive counts, and the latter is more suitable for use cases that allow negative counts:

>>> from collections import Counter
>>> tally = Counter(dogs=5, cats=3)
>>> tally -= Counter(dogs=2, cats=8)    # saturating subtraction
>>> tally
Counter({'dogs': 3})

>>> tally = Counter(dogs=5, cats=3)
>>> tally.subtract(dogs=2, cats=8)      # regular subtraction
>>> tally
Counter({'dogs': 3, 'cats': -5})

(Contributed by Raymond Hettinger.)

The collections.OrderedDict class has a new method move_to_end() which takes an existing key and moves it to either the first or last position in the ordered sequence.

The default is to move an item to the last position. This is equivalent of renewing an entry with od[k] = od.pop(k).

A fast move-to-end operation is useful for resequencing entries. For example, an ordered dictionary can be used to track order of access by aging entries from the oldest to the most recently accessed.

>>> from collections import OrderedDict
>>> d = OrderedDict.fromkeys(['a', 'b', 'X', 'd', 'e'])
>>> list(d)
['a', 'b', 'X', 'd', 'e']
>>> d.move_to_end('X')
>>> list(d)
['a', 'b', 'd', 'e', 'X']

(Contributed by Raymond Hettinger.)

The collections.deque class grew two new methods count() and reverse() that make them more substitutable for list objects:

>>> from collections import deque
>>> d = deque('simsalabim')
>>> d.count('s')
2
>>> d.reverse()
>>> d
deque(['m', 'i', 'b', 'a', 'l', 'a', 's', 'm', 'i', 's'])

(Contributed by Raymond Hettinger.)

threading

The threading module has a new Barrier synchronization class for making multiple threads wait until all of them have reached a common barrier point. Barriers are useful for making sure that a task with multiple preconditions does not run until all of the predecessor tasks are complete.

Barriers can work with an arbitrary number of threads. This is a generalization of a Rendezvous [https://en.wikipedia.org/wiki/Synchronous_rendezvous] which is defined for only two threads.

Implemented as a two-phase cyclic barrier, Barrier objects are suitable for use in loops. The separate filling and draining phases assure that all threads get released (drained) before any one of them can loop back and re-enter the barrier. The barrier fully resets after each cycle.

Example of using barriers:

from threading import Barrier, Thread

def get_votes(site):
    ballots = conduct_election(site)
    all_polls_closed.wait()        # do not count until all polls are closed
    totals = summarize(ballots)
    publish(site, totals)

all_polls_closed = Barrier(len(sites))
for site in sites:
    Thread(target=get_votes, args=(site,)).start()

In this example, the barrier enforces a rule that votes cannot be counted at any polling site until all polls are closed. Notice how a solution with a barrier is similar to one with threading.Thread.join(), but the threads stay alive and continue to do work (summarizing ballots) after the barrier point is crossed.

If any of the predecessor tasks can hang or be delayed, a barrier can be created with an optional timeout parameter. Then if the timeout period elapses before all the predecessor tasks reach the barrier point, all waiting threads are released and a BrokenBarrierError exception is raised:

def get_votes(site):
    ballots = conduct_election(site)
    try:
        all_polls_closed.wait(timeout=midnight - time.now())
    except BrokenBarrierError:
        lockbox = seal_ballots(ballots)
        queue.put(lockbox)
    else:
        totals = summarize(ballots)
        publish(site, totals)

In this example, the barrier enforces a more robust rule. If some election sites do not finish before midnight, the barrier times-out and the ballots are sealed and deposited in a queue for later handling.

See Barrier Synchronization Patterns [https://osl.cs.illinois.edu/media/papers/karmani-2009-barrier_synchronization_pattern.pdf] for more examples of how barriers can be used in parallel computing. Also, there is a simple but thorough explanation of barriers in The Little Book of Semaphores [https://greenteapress.com/semaphores/LittleBookOfSemaphores.pdf], section 3.6.

(Contributed by Kristján Valur Jónsson with an API review by Jeffrey Yasskin in bpo-8777 [https://bugs.python.org/issue?@action=redirect&bpo=8777].)

datetime and time

The datetime module has a new type timezone that implements the tzinfo interface by returning a fixed UTC offset and timezone name. This makes it easier to create timezone-aware datetime objects:

>>> from datetime import datetime, timezone

>>> datetime.now(timezone.utc)
datetime.datetime(2010, 12, 8, 21, 4, 2, 923754, tzinfo=datetime.timezone.utc)

>>> datetime.strptime("01/01/2000 12:00 +0000", "%m/%d/%Y %H:%M %z")
datetime.datetime(2000, 1, 1, 12, 0, tzinfo=datetime.timezone.utc)

Also, timedelta objects can now be multiplied by float and divided by float and int objects. And timedelta objects can now divide one another.

The datetime.date.strftime() method is no longer restricted to years after 1900. The new supported year range is from 1000 to 9999 inclusive.

Whenever a two-digit year is used in a time tuple, the interpretation has been governed by time.accept2dyear. The default is True which means that for a two-digit year, the century is guessed according to the POSIX rules governing the %y strptime format.

Starting with Py3.2, use of the century guessing heuristic will emit a DeprecationWarning. Instead, it is recommended that time.accept2dyear be set to False so that large date ranges can be used without guesswork:

>>> import time, warnings
>>> warnings.resetwarnings()      # remove the default warning filters

>>> time.accept2dyear = True      # guess whether 11 means 11 or 2011
>>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
Warning (from warnings module):
  ...
DeprecationWarning: Century info guessed for a 2-digit year.
'Fri Jan  1 12:34:56 2011'

>>> time.accept2dyear = False     # use the full range of allowable dates
>>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
'Fri Jan  1 12:34:56 11'

Several functions now have significantly expanded date ranges. When time.accept2dyear is false, the time.asctime() function will accept any year that fits in a C int, while the time.mktime() and time.strftime() functions will accept the full range supported by the corresponding operating system functions.

(Contributed by Alexander Belopolsky and Victor Stinner in bpo-1289118 [https://bugs.python.org/issue?@action=redirect&bpo=1289118], bpo-5094 [https://bugs.python.org/issue?@action=redirect&bpo=5094], bpo-6641 [https://bugs.python.org/issue?@action=redirect&bpo=6641], bpo-2706 [https://bugs.python.org/issue?@action=redirect&bpo=2706], bpo-1777412 [https://bugs.python.org/issue?@action=redirect&bpo=1777412], bpo-8013 [https://bugs.python.org/issue?@action=redirect&bpo=8013], and bpo-10827 [https://bugs.python.org/issue?@action=redirect&bpo=10827].)

math

The math module has been updated with six new functions inspired by the C99 standard.

The isfinite() function provides a reliable and fast way to detect special values. It returns True for regular numbers and False for Nan or Infinity:

>>> from math import isfinite
>>> [isfinite(x) for x in (123, 4.56, float('Nan'), float('Inf'))]
[True, True, False, False]

The expm1() function computes e**x-1 for small values of x without incurring the loss of precision that usually accompanies the subtraction of nearly equal quantities:

>>> from math import expm1
>>> expm1(0.013671875)   # more accurate way to compute e**x-1 for a small x
0.013765762467652909

The erf() function computes a probability integral or Gaussian error function [https://en.wikipedia.org/wiki/Error_function]. The complementary error function, erfc(), is 1 - erf(x):

>>> from math import erf, erfc, sqrt
>>> erf(1.0/sqrt(2.0))   # portion of normal distribution within 1 standard deviation
0.682689492137086
>>> erfc(1.0/sqrt(2.0))  # portion of normal distribution outside 1 standard deviation
0.31731050786291404
>>> erf(1.0/sqrt(2.0)) + erfc(1.0/sqrt(2.0))
1.0

The gamma() function is a continuous extension of the factorial function. See https://en.wikipedia.org/wiki/Gamma_function for details. Because the function is related to factorials, it grows large even for small values of x, so there is also a lgamma() function for computing the natural logarithm of the gamma function:

>>> from math import gamma, lgamma
>>> gamma(7.0)           # six factorial
720.0
>>> lgamma(801.0)        # log(800 factorial)
4551.950730698041

(Contributed by Mark Dickinson.)

abc

The abc module now supports abstractclassmethod() and abstractstaticmethod().

These tools make it possible to define an abstract base class that requires a particular classmethod() or staticmethod() to be implemented:

class Temperature(metaclass=abc.ABCMeta):
    @abc.abstractclassmethod
    def from_fahrenheit(cls, t):
        ...
    @abc.abstractclassmethod
    def from_celsius(cls, t):
        ...

(Patch submitted by Daniel Urban; bpo-5867 [https://bugs.python.org/issue?@action=redirect&bpo=5867].)

io

The io.BytesIO has a new method, getbuffer(), which provides functionality similar to memoryview(). It creates an editable view of the data without making a copy. The buffer’s random access and support for slice notation are well-suited to in-place editing:

>>> REC_LEN, LOC_START, LOC_LEN = 34, 7, 11

>>> def change_location(buffer, record_number, location):
...     start = record_number * REC_LEN + LOC_START
...     buffer[start: start+LOC_LEN] = location

>>> import io

>>> byte_stream = io.BytesIO(
...     b'G3805  storeroom  Main chassis    '
...     b'X7899  shipping   Reserve cog     '
...     b'L6988  receiving  Primary sprocket'
... )
>>> buffer = byte_stream.getbuffer()
>>> change_location(buffer, 1, b'warehouse  ')
>>> change_location(buffer, 0, b'showroom   ')
>>> print(byte_stream.getvalue())
b'G3805  showroom   Main chassis    '
b'X7899  warehouse  Reserve cog     '
b'L6988  receiving  Primary sprocket'

(Contributed by Antoine Pitrou in bpo-5506 [https://bugs.python.org/issue?@action=redirect&bpo=5506].)

reprlib

When writing a __repr__() method for a custom container, it is easy to forget to handle the case where a member refers back to the container itself. Python’s builtin objects such as list and set handle self-reference by displaying “…” in the recursive part of the representation string.

To help write such __repr__() methods, the reprlib module has a new decorator, recursive_repr(), for detecting recursive calls to __repr__() and substituting a placeholder string instead:

>>> class MyList(list):
...     @recursive_repr()
...     def __repr__(self):
...         return '<' + '|'.join(map(repr, self)) + '>'
...
>>> m = MyList('abc')
>>> m.append(m)
>>> m.append('x')
>>> print(m)
<'a'|'b'|'c'|...|'x'>

(Contributed by Raymond Hettinger in bpo-9826 [https://bugs.python.org/issue?@action=redirect&bpo=9826] and bpo-9840 [https://bugs.python.org/issue?@action=redirect&bpo=9840].)

logging

In addition to dictionary-based configuration described above, the logging package has many other improvements.

The logging documentation has been augmented by a basic tutorial, an advanced tutorial, and a cookbook of logging recipes. These documents are the fastest way to learn about logging.

The logging.basicConfig() set-up function gained a style argument to support three different types of string formatting. It defaults to “%” for traditional %-formatting, can be set to “{” for the new str.format() style, or can be set to “$” for the shell-style formatting provided by string.Template. The following three configurations are equivalent:

>>> from logging import basicConfig
>>> basicConfig(style='%', format="%(name)s -> %(levelname)s: %(message)s")
>>> basicConfig(style='{', format="{name} -> {levelname} {message}")
>>> basicConfig(style='$', format="$name -> $levelname: $message")

If no configuration is set-up before a logging event occurs, there is now a default configuration using a StreamHandler directed to sys.stderr for events of WARNING level or higher. Formerly, an event occurring before a configuration was set-up would either raise an exception or silently drop the event depending on the value of logging.raiseExceptions. The new default handler is stored in logging.lastResort.

The use of filters has been simplified. Instead of creating a Filter object, the predicate can be any Python callable that returns True or False.

There were a number of other improvements that add flexibility and simplify configuration. See the module documentation for a full listing of changes in Python 3.2.

csv

The csv module now supports a new dialect, unix_dialect, which applies quoting for all fields and a traditional Unix style with '\n' as the line terminator. The registered dialect name is unix.

The csv.DictWriter has a new method, writeheader() for writing-out an initial row to document the field names:

>>> import csv, sys
>>> w = csv.DictWriter(sys.stdout, ['name', 'dept'], dialect='unix')
>>> w.writeheader()
"name","dept"
>>> w.writerows([
...     {'name': 'tom', 'dept': 'accounting'},
...     {'name': 'susan', 'dept': 'Salesl'}])
"tom","accounting"
"susan","sales"

(New dialect suggested by Jay Talbot in bpo-5975 [https://bugs.python.org/issue?@action=redirect&bpo=5975], and the new method suggested by Ed Abraham in bpo-1537721 [https://bugs.python.org/issue?@action=redirect&bpo=1537721].)

contextlib

There is a new and slightly mind-blowing tool ContextDecorator that is helpful for creating a context manager that does double duty as a function decorator.

As a convenience, this new functionality is used by contextmanager() so that no extra effort is needed to support both roles.

The basic idea is that both context managers and function decorators can be used for pre-action and post-action wrappers. Context managers wrap a group of statements using a with statement, and function decorators wrap a group of statements enclosed in a function. So, occasionally there is a need to write a pre-action or post-action wrapper that can be used in either role.

For example, it is sometimes useful to wrap functions or groups of statements with a logger that can track the time of entry and time of exit. Rather than writing both a function decorator and a context manager for the task, the contextmanager() provides both capabilities in a single definition:

from contextlib import contextmanager
import logging

logging.basicConfig(level=logging.INFO)

@contextmanager
def track_entry_and_exit(name):
    logging.info('Entering: %s', name)
    yield
    logging.info('Exiting: %s', name)

Formerly, this would have only been usable as a context manager:

with track_entry_and_exit('widget loader'):
    print('Some time consuming activity goes here')
    load_widget()

Now, it can be used as a decorator as well:

@track_entry_and_exit('widget loader')
def activity():
    print('Some time consuming activity goes here')
    load_widget()

Trying to fulfill two roles at once places some limitations on the technique. Context managers normally have the flexibility to return an argument usable by a with statement, but there is no parallel for function decorators.

In the above example, there is not a clean way for the track_entry_and_exit context manager to return a logging instance for use in the body of enclosed statements.

(Contributed by Michael Foord in bpo-9110 [https://bugs.python.org/issue?@action=redirect&bpo=9110].)

decimal and fractions

Mark Dickinson crafted an elegant and efficient scheme for assuring that different numeric datatypes will have the same hash value whenever their actual values are equal (bpo-8188 [https://bugs.python.org/issue?@action=redirect&bpo=8188]):

assert hash(Fraction(3, 2)) == hash(1.5) == \
       hash(Decimal("1.5")) == hash(complex(1.5, 0))

Some of the hashing details are exposed through a new attribute, sys.hash_info, which describes the bit width of the hash value, the prime modulus, the hash values for infinity and nan, and the multiplier used for the imaginary part of a number:

>>> sys.hash_info
sys.hash_info(width=64, modulus=2305843009213693951, inf=314159, nan=0, imag=1000003)

An early decision to limit the interoperability of various numeric types has been relaxed. It is still unsupported (and ill-advised) to have implicit mixing in arithmetic expressions such as Decimal('1.1') + float('1.1') because the latter loses information in the process of constructing the binary float. However, since existing floating-point value can be converted losslessly to either a decimal or rational representation, it makes sense to add them to the constructor and to support mixed-type comparisons.

The decimal.Decimal constructor now accepts float objects directly so there in no longer a need to use the from_float() method (bpo-8257 [https://bugs.python.org/issue?@action=redirect&bpo=8257]).

Mixed type comparisons are now fully supported so that Decimal objects can be directly compared with float and fractions.Fraction (bpo-2531 [https://bugs.python.org/issue?@action=redirect&bpo=2531] and bpo-8188 [https://bugs.python.org/issue?@action=redirect&bpo=8188]).

Similar changes were made to fractions.Fraction so that the from_float() and from_decimal() methods are no longer needed (bpo-8294 [https://bugs.python.org/issue?@action=redirect&bpo=8294]):

>>> from decimal import Decimal
>>> from fractions import Fraction
>>> Decimal(1.1)
Decimal('1.100000000000000088817841970012523233890533447265625')
>>> Fraction(1.1)
Fraction(2476979795053773, 2251799813685248)

Another useful change for the decimal module is that the Context.clamp attribute is now public. This is useful in creating contexts that correspond to the decimal interchange formats specified in IEEE 754 (see bpo-8540 [https://bugs.python.org/issue?@action=redirect&bpo=8540]).

(Contributed by Mark Dickinson and Raymond Hettinger.)

ftp

The ftplib.FTP class now supports the context management protocol to unconditionally consume socket.error exceptions and to close the FTP connection when done:

>>> from ftplib import FTP
>>> with FTP("ftp1.at.proftpd.org") as ftp:
        ftp.login()
        ftp.dir()

'230 Anonymous login ok, restrictions apply.'
dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 .
dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 ..
dr-xr-xr-x   5 ftp      ftp          4096 May  6 10:43 CentOS
dr-xr-xr-x   3 ftp      ftp            18 Jul 10  2008 Fedora

Other file-like objects such as mmap.mmap and fileinput.input() also grew auto-closing context managers:

with fileinput.input(files=('log1.txt', 'log2.txt')) as f:
    for line in f:
        process(line)

(Contributed by Tarek Ziadé and Giampaolo Rodolà in bpo-4972 [https://bugs.python.org/issue?@action=redirect&bpo=4972], and by Georg Brandl in bpo-8046 [https://bugs.python.org/issue?@action=redirect&bpo=8046] and bpo-1286 [https://bugs.python.org/issue?@action=redirect&bpo=1286].)

The FTP_TLS class now accepts a context parameter, which is a ssl.SSLContext object allowing bundling SSL configuration options, certificates and private keys into a single (potentially long-lived) structure.

(Contributed by Giampaolo Rodolà; bpo-8806 [https://bugs.python.org/issue?@action=redirect&bpo=8806].)

popen

The os.popen() and subprocess.Popen() functions now support with statements for auto-closing of the file descriptors.

(Contributed by Antoine Pitrou and Brian Curtin in bpo-7461 [https://bugs.python.org/issue?@action=redirect&bpo=7461] and bpo-10554 [https://bugs.python.org/issue?@action=redirect&bpo=10554].)

select

The select module now exposes a new, constant attribute, PIPE_BUF, which gives the minimum number of bytes which are guaranteed not to block when select.select() says a pipe is ready for writing.

>>> import select
>>> select.PIPE_BUF
512

(Available on Unix systems. Patch by Sébastien Sablé in bpo-9862 [https://bugs.python.org/issue?@action=redirect&bpo=9862])

gzip and zipfile

gzip.GzipFile now implements the io.BufferedIOBase abstract base class (except for truncate()). It also has a peek() method and supports unseekable as well as zero-padded file objects.

The gzip module also gains the compress() and decompress() functions for easier in-memory compression and decompression. Keep in mind that text needs to be encoded as bytes before compressing and decompressing:

>>> import gzip
>>> s = 'Three shall be the number thou shalt count, '
>>> s += 'and the number of the counting shall be three'
>>> b = s.encode()                        # convert to utf-8
>>> len(b)
89
>>> c = gzip.compress(b)
>>> len(c)
77
>>> gzip.decompress(c).decode()[:42]      # decompress and convert to text
'Three shall be the number thou shalt count'

(Contributed by Anand B. Pillai in bpo-3488 [https://bugs.python.org/issue?@action=redirect&bpo=3488]; and by Antoine Pitrou, Nir Aides and Brian Curtin in bpo-9962 [https://bugs.python.org/issue?@action=redirect&bpo=9962], bpo-1675951 [https://bugs.python.org/issue?@action=redirect&bpo=1675951], bpo-7471 [https://bugs.python.org/issue?@action=redirect&bpo=7471] and bpo-2846 [https://bugs.python.org/issue?@action=redirect&bpo=2846].)

Also, the zipfile.ZipExtFile class was reworked internally to represent files stored inside an archive. The new implementation is significantly faster and can be wrapped in an io.BufferedReader object for more speedups. It also solves an issue where interleaved calls to read and readline gave the wrong results.

(Patch submitted by Nir Aides in bpo-7610 [https://bugs.python.org/issue?@action=redirect&bpo=7610].)

tarfile

The TarFile class can now be used as a context manager. In addition, its add() method has a new option, filter, that controls which files are added to the archive and allows the file metadata to be edited.

The new filter option replaces the older, less flexible exclude parameter which is now deprecated. If specified, the optional filter parameter needs to be a keyword argument. The user-supplied filter function accepts a TarInfo object and returns an updated TarInfo object, or if it wants the file to be excluded, the function can return None:

>>> import tarfile, glob

>>> def myfilter(tarinfo):
...     if tarinfo.isfile():             # only save real files
...         tarinfo.uname = 'monty'      # redact the user name
...         return tarinfo

>>> with tarfile.open(name='myarchive.tar.gz', mode='w:gz') as tf:
...     for filename in glob.glob('*.txt'):
...         tf.add(filename, filter=myfilter)
...     tf.list()
-rw-r--r-- monty/501        902 2011-01-26 17:59:11 annotations.txt
-rw-r--r-- monty/501        123 2011-01-26 17:59:11 general_questions.txt
-rw-r--r-- monty/501       3514 2011-01-26 17:59:11 prion.txt
-rw-r--r-- monty/501        124 2011-01-26 17:59:11 py_todo.txt
-rw-r--r-- monty/501       1399 2011-01-26 17:59:11 semaphore_notes.txt

(Proposed by Tarek Ziadé and implemented by Lars Gustäbel in bpo-6856 [https://bugs.python.org/issue?@action=redirect&bpo=6856].)

hashlib

The hashlib module has two new constant attributes listing the hashing algorithms guaranteed to be present in all implementations and those available on the current implementation:

>>> import hashlib

>>> hashlib.algorithms_guaranteed
{'sha1', 'sha224', 'sha384', 'sha256', 'sha512', 'md5'}

>>> hashlib.algorithms_available
{'md2', 'SHA256', 'SHA512', 'dsaWithSHA', 'mdc2', 'SHA224', 'MD4', 'sha256',
'sha512', 'ripemd160', 'SHA1', 'MDC2', 'SHA', 'SHA384', 'MD2',
'ecdsa-with-SHA1','md4', 'md5', 'sha1', 'DSA-SHA', 'sha224',
'dsaEncryption', 'DSA', 'RIPEMD160', 'sha', 'MD5', 'sha384'}

(Suggested by Carl Chenet in bpo-7418 [https://bugs.python.org/issue?@action=redirect&bpo=7418].)

ast

The ast module has a wonderful a general-purpose tool for safely evaluating expression strings using the Python literal syntax. The ast.literal_eval() function serves as a secure alternative to the builtin eval() function which is easily abused. Python 3.2 adds bytes and set literals to the list of supported types: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, and None.

>>> from ast import literal_eval

>>> request = "{'req': 3, 'func': 'pow', 'args': (2, 0.5)}"
>>> literal_eval(request)
{'args': (2, 0.5), 'req': 3, 'func': 'pow'}

>>> request = "os.system('do something harmful')"
>>> literal_eval(request)
Traceback (most recent call last):
  ...
ValueError: malformed node or string: <_ast.Call object at 0x101739a10>

(Implemented by Benjamin Peterson and Georg Brandl.)

os

Different operating systems use various encodings for filenames and environment variables. The os module provides two new functions, fsencode() and fsdecode(), for encoding and decoding filenames:

>>> import os
>>> filename = 'Sehenswürdigkeiten'
>>> os.fsencode(filename)
b'Sehensw\xc3\xbcrdigkeiten'

Some operating systems allow direct access to encoded bytes in the environment. If so, the os.supports_bytes_environ constant will be true.

For direct access to encoded environment variables (if available), use the new os.getenvb() function or use os.environb which is a bytes version of os.environ.

(Contributed by Victor Stinner.)

shutil

The shutil.copytree() function has two new options:

ignore_dangling_symlinks: when symlinks=False so that the function copies a file pointed to by a symlink, not the symlink itself. This option will silence the error raised if the file doesn’t exist.

copy_function: is a callable that will be used to copy files. shutil.copy2() is used by default.

(Contributed by Tarek Ziadé.)

In addition, the shutil module now supports archiving operations for zipfiles, uncompressed tarfiles, gzipped tarfiles, and bzipped tarfiles. And there are functions for registering additional archiving file formats (such as xz compressed tarfiles or custom formats).

The principal functions are make_archive() and unpack_archive(). By default, both operate on the current directory (which can be set by os.chdir()) and on any sub-directories. The archive filename needs to be specified with a full pathname. The archiving step is non-destructive (the original files are left unchanged).

>>> import shutil, pprint

>>> os.chdir('mydata')  # change to the source directory
>>> f = shutil.make_archive('/var/backup/mydata',
...                         'zip')      # archive the current directory
>>> f                                   # show the name of archive
'/var/backup/mydata.zip'
>>> os.chdir('tmp')                     # change to an unpacking
>>> shutil.unpack_archive('/var/backup/mydata.zip')  # recover the data

>>> pprint.pprint(shutil.get_archive_formats())  # display known formats
[('bztar', "bzip2'ed tar-file"),
 ('gztar', "gzip'ed tar-file"),
 ('tar', 'uncompressed tar file'),
 ('zip', 'ZIP file')]

>>> shutil.register_archive_format(     # register a new archive format
...     name='xz',
...     function=xz.compress,           # callable archiving function
...     extra_args=[('level', 8)],      # arguments to the function
...     description='xz compression'
... )

(Contributed by Tarek Ziadé.)

sqlite3

The sqlite3 module was updated to pysqlite version 2.6.0. It has two new capabilities.

The sqlite3.Connection.in_transit attribute is true if there is an active transaction for uncommitted changes.

The sqlite3.Connection.enable_load_extension() and sqlite3.Connection.load_extension() methods allows you to load SQLite extensions from “.so” files. One well-known extension is the fulltext-search extension distributed with SQLite.

(Contributed by R. David Murray and Shashwat Anand; bpo-8845 [https://bugs.python.org/issue?@action=redirect&bpo=8845].)

html

A new html module was introduced with only a single function, escape(), which is used for escaping reserved characters from HTML markup:

>>> import html
>>> html.escape('x > 2 && x < 7')
'x &gt; 2 &amp;&amp; x &lt; 7'

socket

The socket module has two new improvements.

Socket objects now have a detach() method which puts the socket into closed state without actually closing the underlying file descriptor. The latter can then be reused for other purposes. (Added by Antoine Pitrou; bpo-8524 [https://bugs.python.org/issue?@action=redirect&bpo=8524].)

socket.create_connection() now supports the context management protocol to unconditionally consume socket.error exceptions and to close the socket when done. (Contributed by Giampaolo Rodolà; bpo-9794 [https://bugs.python.org/issue?@action=redirect&bpo=9794].)

ssl

The ssl module added a number of features to satisfy common requirements for secure (encrypted, authenticated) internet connections:

A new class, SSLContext, serves as a container for persistent SSL data, such as protocol settings, certificates, private keys, and various other options. It includes a wrap_socket() for creating an SSL socket from an SSL context.

A new function, ssl.match_hostname(), supports server identity verification for higher-level protocols by implementing the rules of HTTPS (from RFC 2818 [https://datatracker.ietf.org/doc/html/rfc2818.html]) which are also suitable for other protocols.

The ssl.wrap_socket() constructor function now takes a ciphers argument. The ciphers string lists the allowed encryption algorithms using the format described in the OpenSSL documentation [https://docs.openssl.org/1.0.2/man1/ciphers/#cipher-list-format].

When linked against recent versions of OpenSSL, the ssl module now supports the Server Name Indication extension to the TLS protocol, allowing multiple “virtual hosts” using different certificates on a single IP port. This extension is only supported in client mode, and is activated by passing the server_hostname argument to ssl.SSLContext.wrap_socket().

Various options have been added to the ssl module, such as OP_NO_SSLv2 which disables the insecure and obsolete SSLv2 protocol.

The extension now loads all the OpenSSL ciphers and digest algorithms. If some SSL certificates cannot be verified, they are reported as an “unknown algorithm” error.

The version of OpenSSL being used is now accessible using the module attributes ssl.OPENSSL_VERSION (a string), ssl.OPENSSL_VERSION_INFO (a 5-tuple), and ssl.OPENSSL_VERSION_NUMBER (an integer).

(Contributed by Antoine Pitrou in bpo-8850 [https://bugs.python.org/issue?@action=redirect&bpo=8850], bpo-1589 [https://bugs.python.org/issue?@action=redirect&bpo=1589], bpo-8322 [https://bugs.python.org/issue?@action=redirect&bpo=8322], bpo-5639 [https://bugs.python.org/issue?@action=redirect&bpo=5639], bpo-4870 [https://bugs.python.org/issue?@action=redirect&bpo=4870], bpo-8484 [https://bugs.python.org/issue?@action=redirect&bpo=8484], and bpo-8321 [https://bugs.python.org/issue?@action=redirect&bpo=8321].)

nntp

The nntplib module has a revamped implementation with better bytes and text semantics as well as more practical APIs. These improvements break compatibility with the nntplib version in Python 3.1, which was partly dysfunctional in itself.

Support for secure connections through both implicit (using nntplib.NNTP_SSL) and explicit (using nntplib.NNTP.starttls()) TLS has also been added.

(Contributed by Antoine Pitrou in bpo-9360 [https://bugs.python.org/issue?@action=redirect&bpo=9360] and Andrew Vant in bpo-1926 [https://bugs.python.org/issue?@action=redirect&bpo=1926].)

certificates

http.client.HTTPSConnection, urllib.request.HTTPSHandler and urllib.request.urlopen() now take optional arguments to allow for server certificate checking against a set of Certificate Authorities, as recommended in public uses of HTTPS.

(Added by Antoine Pitrou, bpo-9003 [https://bugs.python.org/issue?@action=redirect&bpo=9003].)

imaplib

Support for explicit TLS on standard IMAP4 connections has been added through the new imaplib.IMAP4.starttls method.

(Contributed by Lorenzo M. Catucci and Antoine Pitrou, bpo-4471 [https://bugs.python.org/issue?@action=redirect&bpo=4471].)

http.client

There were a number of small API improvements in the http.client module. The old-style HTTP 0.9 simple responses are no longer supported and the strict parameter is deprecated in all classes.

The HTTPConnection and HTTPSConnection classes now have a source_address parameter for a (host, port) tuple indicating where the HTTP connection is made from.

Support for certificate checking and HTTPS virtual hosts were added to HTTPSConnection.

The request() method on connection objects allowed an optional body argument so that a file object could be used to supply the content of the request. Conveniently, the body argument now also accepts an iterable object so long as it includes an explicit Content-Length header. This extended interface is much more flexible than before.

To establish an HTTPS connection through a proxy server, there is a new set_tunnel() method that sets the host and port for HTTP Connect tunneling.

To match the behavior of http.server, the HTTP client library now also encodes headers with ISO-8859-1 (Latin-1) encoding. It was already doing that for incoming headers, so now the behavior is consistent for both incoming and outgoing traffic. (See work by Armin Ronacher in bpo-10980 [https://bugs.python.org/issue?@action=redirect&bpo=10980].)

unittest

The unittest module has a number of improvements supporting test discovery for packages, easier experimentation at the interactive prompt, new testcase methods, improved diagnostic messages for test failures, and better method names.

The command-line call python -m unittest can now accept file paths instead of module names for running specific tests (bpo-10620 [https://bugs.python.org/issue?@action=redirect&bpo=10620]). The new test discovery can find tests within packages, locating any test importable from the top-level directory. The top-level directory can be specified with the -t option, a pattern for matching files with -p, and a directory to start discovery with -s:

$ python -m unittest discover -s my_proj_dir -p _test.py

(Contributed by Michael Foord.)

Experimentation at the interactive prompt is now easier because the unittest.TestCase class can now be instantiated without arguments:

>>> from unittest import TestCase
>>> TestCase().assertEqual(pow(2, 3), 8)

(Contributed by Michael Foord.)

The unittest module has two new methods, assertWarns() and assertWarnsRegex() to verify that a given warning type is triggered by the code under test:

with self.assertWarns(DeprecationWarning):
    legacy_function('XYZ')

(Contributed by Antoine Pitrou, bpo-9754 [https://bugs.python.org/issue?@action=redirect&bpo=9754].)

Another new method, assertCountEqual() is used to compare two iterables to determine if their element counts are equal (whether the same elements are present with the same number of occurrences regardless of order):

def test_anagram(self):
    self.assertCountEqual('algorithm', 'logarithm')

(Contributed by Raymond Hettinger.)

A principal feature of the unittest module is an effort to produce meaningful diagnostics when a test fails. When possible, the failure is recorded along with a diff of the output. This is especially helpful for analyzing log files of failed test runs. However, since diffs can sometime be voluminous, there is a new maxDiff attribute that sets maximum length of diffs displayed.

In addition, the method names in the module have undergone a number of clean-ups.

For example, assertRegex() is the new name for assertRegexpMatches() which was misnamed because the test uses re.search(), not re.match(). Other methods using regular expressions are now named using short form “Regex” in preference to “Regexp” – this matches the names used in other unittest implementations, matches Python’s old name for the re module, and it has unambiguous camel-casing.

(Contributed by Raymond Hettinger and implemented by Ezio Melotti.)

To improve consistency, some long-standing method aliases are being deprecated in favor of the preferred names:

Old Name

Preferred Name

assert_()

assertTrue()

assertEquals()

assertEqual()

assertNotEquals()

assertNotEqual()

assertAlmostEquals()

assertAlmostEqual()

assertNotAlmostEquals()

assertNotAlmostEqual()

Likewise, the TestCase.fail* methods deprecated in Python 3.1 are expected to be removed in Python 3.3.

(Contributed by Ezio Melotti; bpo-9424 [https://bugs.python.org/issue?@action=redirect&bpo=9424].)

The assertDictContainsSubset() method was deprecated because it was misimplemented with the arguments in the wrong order. This created hard-to-debug optical illusions where tests like TestCase().assertDictContainsSubset({'a':1, 'b':2}, {'a':1}) would fail.

(Contributed by Raymond Hettinger.)

random

The integer methods in the random module now do a better job of producing uniform distributions. Previously, they computed selections with int(n*random()) which had a slight bias whenever n was not a power of two. Now, multiple selections are made from a range up to the next power of two and a selection is kept only when it falls within the range 0 <= x < n. The functions and methods affected are randrange(), randint(), choice(), shuffle() and sample().

(Contributed by Raymond Hettinger; bpo-9025 [https://bugs.python.org/issue?@action=redirect&bpo=9025].)

poplib

POP3_SSL class now accepts a context parameter, which is a ssl.SSLContext object allowing bundling SSL configuration options, certificates and private keys into a single (potentially long-lived) structure.

(Contributed by Giampaolo Rodolà; bpo-8807 [https://bugs.python.org/issue?@action=redirect&bpo=8807].)

asyncore

asyncore.dispatcher now provides a handle_accepted() method returning a (sock, addr) pair which is called when a connection has actually been established with a new remote endpoint. This is supposed to be used as a replacement for old handle_accept() and avoids the user to call accept() directly.

(Contributed by Giampaolo Rodolà; bpo-6706 [https://bugs.python.org/issue?@action=redirect&bpo=6706].)

tempfile

The tempfile module has a new context manager, TemporaryDirectory which provides easy deterministic cleanup of temporary directories:

with tempfile.TemporaryDirectory() as tmpdirname:
    print('created temporary dir:', tmpdirname)

(Contributed by Neil Schemenauer and Nick Coghlan; bpo-5178 [https://bugs.python.org/issue?@action=redirect&bpo=5178].)

inspect

The inspect module has a new function getgeneratorstate() to easily identify the current state of a generator-iterator:

>>> from inspect import getgeneratorstate
>>> def gen():
...     yield 'demo'
...
>>> g = gen()
>>> getgeneratorstate(g)
'GEN_CREATED'
>>> next(g)
'demo'
>>> getgeneratorstate(g)
'GEN_SUSPENDED'
>>> next(g, None)
>>> getgeneratorstate(g)
'GEN_CLOSED'

(Contributed by Rodolpho Eckhardt and Nick Coghlan, bpo-10220 [https://bugs.python.org/issue?@action=redirect&bpo=10220].)

To support lookups without the possibility of activating a dynamic attribute, the inspect module has a new function, getattr_static(). Unlike hasattr(), this is a true read-only search, guaranteed not to change state while it is searching:

>>> class A:
...     @property
...     def f(self):
...         print('Running')
...         return 10
...
>>> a = A()
>>> getattr(a, 'f')
Running
10
>>> inspect.getattr_static(a, 'f')
<property object at 0x1022bd788>

(Contributed by Michael Foord.)

pydoc

The pydoc module now provides a much-improved web server interface, as well as a new command-line option -b to automatically open a browser window to display that server:

$ pydoc3.2 -b

(Contributed by Ron Adam; bpo-2001 [https://bugs.python.org/issue?@action=redirect&bpo=2001].)

dis

The dis module gained two new functions for inspecting code, code_info() and show_code(). Both provide detailed code object information for the supplied function, method, source code string or code object. The former returns a string and the latter prints it:

>>> import dis, random
>>> dis.show_code(random.choice)
Name:              choice
Filename:          /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/random.py
Argument count:    2
Kw-only arguments: 0
Number of locals:  3
Stack size:        11
Flags:             OPTIMIZED, NEWLOCALS, NOFREE
Constants:
   0: 'Choose a random element from a non-empty sequence.'
   1: 'Cannot choose from an empty sequence'
Names:
   0: _randbelow
   1: len
   2: ValueError
   3: IndexError
Variable names:
   0: self
   1: seq
   2: i

In addition, the dis() function now accepts string arguments so that the common idiom dis(compile(s, '', 'eval')) can be shortened to dis(s):

>>> dis('3*x+1 if x%2==1 else x//2')
  1           0 LOAD_NAME                0 (x)
              3 LOAD_CONST               0 (2)
              6 BINARY_MODULO
              7 LOAD_CONST               1 (1)
             10 COMPARE_OP               2 (==)
             13 POP_JUMP_IF_FALSE       28
             16 LOAD_CONST               2 (3)
             19 LOAD_NAME                0 (x)
             22 BINARY_MULTIPLY
             23 LOAD_CONST               1 (1)
             26 BINARY_ADD
             27 RETURN_VALUE
        >>   28 LOAD_NAME                0 (x)
             31 LOAD_CONST               0 (2)
             34 BINARY_FLOOR_DIVIDE
             35 RETURN_VALUE

Taken together, these improvements make it easier to explore how CPython is implemented and to see for yourself what the language syntax does under-the-hood.

(Contributed by Nick Coghlan in bpo-9147 [https://bugs.python.org/issue?@action=redirect&bpo=9147].)

dbm

All database modules now support the get() and setdefault() methods.

(Suggested by Ray Allen in bpo-9523 [https://bugs.python.org/issue?@action=redirect&bpo=9523].)

ctypes

A new type, ctypes.c_ssize_t represents the C ssize_t datatype.

site

The site module has three new functions useful for reporting on the details of a given Python installation.

getsitepackages() lists all global site-packages directories.

getuserbase() reports on the user’s base directory where data can be stored.

getusersitepackages() reveals the user-specific site-packages directory path.

>>> import site
>>> site.getsitepackages()
['/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages',
 '/Library/Frameworks/Python.framework/Versions/3.2/lib/site-python',
 '/Library/Python/3.2/site-packages']
>>> site.getuserbase()
'/Users/raymondhettinger/Library/Python/3.2'
>>> site.getusersitepackages()
'/Users/raymondhettinger/Library/Python/3.2/lib/python/site-packages'

Conveniently, some of site’s functionality is accessible directly from the command-line:

$ python -m site --user-base
/Users/raymondhettinger/.local
$ python -m site --user-site
/Users/raymondhettinger/.local/lib/python3.2/site-packages

(Contributed by Tarek Ziadé in bpo-6693 [https://bugs.python.org/issue?@action=redirect&bpo=6693].)

sysconfig

The new sysconfig module makes it straightforward to discover installation paths and configuration variables that vary across platforms and installations.

The module offers access simple access functions for platform and version information:

get_platform() returning values like linux-i586 or macosx-10.6-ppc.

get_python_version() returns a Python version string such as “3.2”.

It also provides access to the paths and variables corresponding to one of seven named schemes used by distutils. Those include posix_prefix, posix_home, posix_user, nt, nt_user, os2, os2_home:

get_paths() makes a dictionary containing installation paths for the current installation scheme.

get_config_vars() returns a dictionary of platform specific variables.

There is also a convenient command-line interface:

C:\Python32>python -m sysconfig
Platform: "win32"
Python version: "3.2"
Current installation scheme: "nt"

Paths:
        data = "C:\Python32"
        include = "C:\Python32\Include"
        platinclude = "C:\Python32\Include"
        platlib = "C:\Python32\Lib\site-packages"
        platstdlib = "C:\Python32\Lib"
        purelib = "C:\Python32\Lib\site-packages"
        scripts = "C:\Python32\Scripts"
        stdlib = "C:\Python32\Lib"

Variables:
        BINDIR = "C:\Python32"
        BINLIBDEST = "C:\Python32\Lib"
        EXE = ".exe"
        INCLUDEPY = "C:\Python32\Include"
        LIBDEST = "C:\Python32\Lib"
        SO = ".pyd"
        VERSION = "32"
        abiflags = ""
        base = "C:\Python32"
        exec_prefix = "C:\Python32"
        platbase = "C:\Python32"
        prefix = "C:\Python32"
        projectbase = "C:\Python32"
        py_version = "3.2"
        py_version_nodot = "32"
        py_version_short = "3.2"
        srcdir = "C:\Python32"
        userbase = "C:\Documents and Settings\Raymond\Application Data\Python"

(Moved out of Distutils by Tarek Ziadé.)

pdb

The pdb debugger module gained a number of usability improvements:

pdb.py now has a -c option that executes commands as given in a .pdbrc script file.

A .pdbrc script file can contain continue and next commands that continue debugging.

The Pdb class constructor now accepts a nosigint argument.

New commands: l(list), ll(long list) and source for listing source code.

New commands: display and undisplay for showing or hiding the value of an expression if it has changed.

New command: interact for starting an interactive interpreter containing the global and local names found in the current scope.

Breakpoints can be cleared by breakpoint number.

(Contributed by Georg Brandl, Antonio Cuni and Ilya Sandler.)

configparser

The configparser module was modified to improve usability and predictability of the default parser and its supported INI syntax. The old ConfigParser class was removed in favor of SafeConfigParser which has in turn been renamed to ConfigParser. Support for inline comments is now turned off by default and section or option duplicates are not allowed in a single configuration source.

Config parsers gained a new API based on the mapping protocol:

>>> parser = ConfigParser()
>>> parser.read_string("""
... [DEFAULT]
... location = upper left
... visible = yes
... editable = no
... color = blue
...
... [main]
... title = Main Menu
... color = green
...
... [options]
... title = Options
... """)
>>> parser['main']['color']
'green'
>>> parser['main']['editable']
'no'
>>> section = parser['options']
>>> section['title']
'Options'
>>> section['title'] = 'Options (editable: %(editable)s)'
>>> section['title']
'Options (editable: no)'

The new API is implemented on top of the classical API, so custom parser subclasses should be able to use it without modifications.

The INI file structure accepted by config parsers can now be customized. Users can specify alternative option/value delimiters and comment prefixes, change the name of the DEFAULT section or switch the interpolation syntax.

There is support for pluggable interpolation including an additional interpolation handler ExtendedInterpolation:

>>> parser = ConfigParser(interpolation=ExtendedInterpolation())
>>> parser.read_dict({'buildout': {'directory': '/home/ambv/zope9'},
...                   'custom': {'prefix': '/usr/local'}})
>>> parser.read_string("""
... [buildout]
... parts =
...   zope9
...   instance
... find-links =
...   ${buildout:directory}/downloads/dist
...
... [zope9]
... recipe = plone.recipe.zope9install
... location = /opt/zope
...
... [instance]
... recipe = plone.recipe.zope9instance
... zope9-location = ${zope9:location}
... zope-conf = ${custom:prefix}/etc/zope.conf
... """)
>>> parser['buildout']['find-links']
'\n/home/ambv/zope9/downloads/dist'
>>> parser['instance']['zope-conf']
'/usr/local/etc/zope.conf'
>>> instance = parser['instance']
>>> instance['zope-conf']
'/usr/local/etc/zope.conf'
>>> instance['zope9-location']
'/opt/zope'

A number of smaller features were also introduced, like support for specifying encoding in read operations, specifying fallback values for get-functions, or reading directly from dictionaries and strings.

(All changes contributed by Łukasz Langa.)

urllib.parse

A number of usability improvements were made for the urllib.parse module.

The urlparse() function now supports IPv6 [https://en.wikipedia.org/wiki/IPv6] addresses as described in RFC 2732 [https://datatracker.ietf.org/doc/html/rfc2732.html]:

>>> import urllib.parse
>>> urllib.parse.urlparse('http://[dead:beef:cafe:5417:affe:8FA3:deaf:feed]/foo/')
ParseResult(scheme='http',
            netloc='[dead:beef:cafe:5417:affe:8FA3:deaf:feed]',
            path='/foo/',
            params='',
            query='',
            fragment='')

The urldefrag() function now returns a named tuple:

>>> r = urllib.parse.urldefrag('http://python.org/about/#target')
>>> r
DefragResult(url='http://python.org/about/', fragment='target')
>>> r[0]
'http://python.org/about/'
>>> r.fragment
'target'

And, the urlencode() function is now much more flexible, accepting either a string or bytes type for the query argument. If it is a string, then the safe, encoding, and error parameters are sent to quote_plus() for encoding:

>>> urllib.parse.urlencode([
...      ('type', 'telenovela'),
...      ('name', '¿Dónde Está Elisa?')],
...      encoding='latin-1')
'type=telenovela&name=%BFD%F3nde+Est%E1+Elisa%3F'

As detailed in ASCII로 인코딩된 바이트열 구문 분석, all the urllib.parse functions now accept ASCII-encoded byte strings as input, so long as they are not mixed with regular strings. If ASCII-encoded byte strings are given as parameters, the return types will also be an ASCII-encoded byte strings:

>>> urllib.parse.urlparse(b'http://www.python.org:80/about/')
ParseResultBytes(scheme=b'http', netloc=b'www.python.org:80',
                 path=b'/about/', params=b'', query=b'', fragment=b'')

(Work by Nick Coghlan, Dan Mahn, and Senthil Kumaran in bpo-2987 [https://bugs.python.org/issue?@action=redirect&bpo=2987], bpo-5468 [https://bugs.python.org/issue?@action=redirect&bpo=5468], and bpo-9873 [https://bugs.python.org/issue?@action=redirect&bpo=9873].)

mailbox

Thanks to a concerted effort by R. David Murray, the mailbox module has been fixed for Python 3.2. The challenge was that mailbox had been originally designed with a text interface, but email messages are best represented with bytes because various parts of a message may have different encodings.

The solution harnessed the email package’s binary support for parsing arbitrary email messages. In addition, the solution required a number of API changes.

As expected, the add() method for mailbox.Mailbox objects now accepts binary input.

StringIO and text file input are deprecated. Also, string input will fail early if non-ASCII characters are used. Previously it would fail when the email was processed in a later step.

There is also support for binary output. The get_file() method now returns a file in the binary mode (where it used to incorrectly set the file to text-mode). There is also a new get_bytes() method that returns a bytes representation of a message corresponding to a given key.

It is still possible to get non-binary output using the old API’s get_string() method, but that approach is not very useful. Instead, it is best to extract messages from a Message object or to load them from binary input.

(Contributed by R. David Murray, with efforts from Steffen Daode Nurpmeso and an initial patch by Victor Stinner in bpo-9124 [https://bugs.python.org/issue?@action=redirect&bpo=9124].)

turtledemo

The demonstration code for the turtle module was moved from the Demo directory to main library. It includes over a dozen sample scripts with lively displays. Being on sys.path, it can now be run directly from the command-line:

$ python -m turtledemo

(Moved from the Demo directory by Alexander Belopolsky in bpo-10199 [https://bugs.python.org/issue?@action=redirect&bpo=10199].)

Multi-threading

The mechanism for serializing execution of concurrently running Python threads (generally known as the GIL or Global Interpreter Lock) has been rewritten. Among the objectives were more predictable switching intervals and reduced overhead due to lock contention and the number of ensuing system calls. The notion of a “check interval” to allow thread switches has been abandoned and replaced by an absolute duration expressed in seconds. This parameter is tunable through sys.setswitchinterval(). It currently defaults to 5 milliseconds.

Additional details about the implementation can be read from a python-dev mailing-list message [https://mail.python.org/pipermail/python-dev/2009-October/093321.html] (however, “priority requests” as exposed in this message have not been kept for inclusion).

(Contributed by Antoine Pitrou.)

Regular and recursive locks now accept an optional timeout argument to their acquire() method. (Contributed by Antoine Pitrou; bpo-7316 [https://bugs.python.org/issue?@action=redirect&bpo=7316].)

Similarly, threading.Semaphore.acquire() also gained a timeout argument. (Contributed by Torsten Landschoff; bpo-850728 [https://bugs.python.org/issue?@action=redirect&bpo=850728].)

Regular and recursive lock acquisitions can now be interrupted by signals on platforms using Pthreads. This means that Python programs that deadlock while acquiring locks can be successfully killed by repeatedly sending SIGINT to the process (by pressing Ctrl+C in most shells). (Contributed by Reid Kleckner; bpo-8844 [https://bugs.python.org/issue?@action=redirect&bpo=8844].)

Optimizations

A number of small performance enhancements have been added:

Python’s peephole optimizer now recognizes patterns such x in {1, 2, 3} as being a test for membership in a set of constants. The optimizer recasts the set as a frozenset and stores the pre-built constant.

Now that the speed penalty is gone, it is practical to start writing membership tests using set-notation. This style is both semantically clear and operationally fast:

extension = name.rpartition('.')[2]
if extension in {'xml', 'html', 'xhtml', 'css'}:
    handle(name)

(Patch and additional tests contributed by Dave Malcolm; bpo-6690 [https://bugs.python.org/issue?@action=redirect&bpo=6690]).

Serializing and unserializing data using the pickle module is now several times faster.

(Contributed by Alexandre Vassalotti, Antoine Pitrou and the Unladen Swallow team in bpo-9410 [https://bugs.python.org/issue?@action=redirect&bpo=9410] and bpo-3873 [https://bugs.python.org/issue?@action=redirect&bpo=3873].)

The Timsort algorithm [https://en.wikipedia.org/wiki/Timsort] used in list.sort() and sorted() now runs faster and uses less memory when called with a key function. Previously, every element of a list was wrapped with a temporary object that remembered the key value associated with each element. Now, two arrays of keys and values are sorted in parallel. This saves the memory consumed by the sort wrappers, and it saves time lost to delegating comparisons.

(Patch by Daniel Stutzbach in bpo-9915 [https://bugs.python.org/issue?@action=redirect&bpo=9915].)

JSON decoding performance is improved and memory consumption is reduced whenever the same string is repeated for multiple keys. Also, JSON encoding now uses the C speedups when the sort_keys argument is true.

(Contributed by Antoine Pitrou in bpo-7451 [https://bugs.python.org/issue?@action=redirect&bpo=7451] and by Raymond Hettinger and Antoine Pitrou in bpo-10314 [https://bugs.python.org/issue?@action=redirect&bpo=10314].)

Recursive locks (created with the threading.RLock() API) now benefit from a C implementation which makes them as fast as regular locks, and between 10x and 15x faster than their previous pure Python implementation.

(Contributed by Antoine Pitrou; bpo-3001 [https://bugs.python.org/issue?@action=redirect&bpo=3001].)

The fast-search algorithm in stringlib is now used by the split(), rsplit(), splitlines() and replace() methods on bytes, bytearray and str objects. Likewise, the algorithm is also used by rfind(), rindex(), rsplit() and rpartition().

(Patch by Florent Xicluna in bpo-7622 [https://bugs.python.org/issue?@action=redirect&bpo=7622] and bpo-7462 [https://bugs.python.org/issue?@action=redirect&bpo=7462].)

Integer to string conversions now work two “digits” at a time, reducing the number of division and modulo operations.

(bpo-6713 [https://bugs.python.org/issue?@action=redirect&bpo=6713] by Gawain Bolton, Mark Dickinson, and Victor Stinner.)

There were several other minor optimizations. Set differencing now runs faster when one operand is much larger than the other (patch by Andress Bennetts in bpo-8685 [https://bugs.python.org/issue?@action=redirect&bpo=8685]). The array.repeat() method has a faster implementation (bpo-1569291 [https://bugs.python.org/issue?@action=redirect&bpo=1569291] by Alexander Belopolsky). The BaseHTTPRequestHandler has more efficient buffering (bpo-3709 [https://bugs.python.org/issue?@action=redirect&bpo=3709] by Andrew Schaaf). The operator.attrgetter() function has been sped-up (bpo-10160 [https://bugs.python.org/issue?@action=redirect&bpo=10160] by Christos Georgiou). And ConfigParser loads multi-line arguments a bit faster (bpo-7113 [https://bugs.python.org/issue?@action=redirect&bpo=7113] by Łukasz Langa).

Unicode

Python has been updated to Unicode 6.0.0 [https://unicode.org/versions/Unicode6.0.0/]. The update to the standard adds over 2,000 new characters including emoji [https://en.wikipedia.org/wiki/Emoji] symbols which are important for mobile phones.

In addition, the updated standard has altered the character properties for two Kannada characters (U+0CF1, U+0CF2) and one New Tai Lue numeric character (U+19DA), making the former eligible for use in identifiers while disqualifying the latter. For more information, see Unicode Character Database Changes [https://www.unicode.org/versions/Unicode6.0.0/#Database_Changes].

Codecs

Support was added for cp720 Arabic DOS encoding (bpo-1616979 [https://bugs.python.org/issue?@action=redirect&bpo=1616979]).

MBCS encoding no longer ignores the error handler argument. In the default strict mode, it raises an UnicodeDecodeError when it encounters an undecodable byte sequence and an UnicodeEncodeError for an unencodable character.

The MBCS codec supports 'strict' and 'ignore' error handlers for decoding, and 'strict' and 'replace' for encoding.

To emulate Python3.1 MBCS encoding, select the 'ignore' handler for decoding and the 'replace' handler for encoding.

On Mac OS X, Python decodes command line arguments with 'utf-8' rather than the locale encoding.

By default, tarfile uses 'utf-8' encoding on Windows (instead of 'mbcs') and the 'surrogateescape' error handler on all operating systems.

Documentation

The documentation continues to be improved.

A table of quick links has been added to the top of lengthy sections such as 내장 함수. In the case of itertools, the links are accompanied by tables of cheatsheet-style summaries to provide an overview and memory jog without having to read all of the docs.

In some cases, the pure Python source code can be a helpful adjunct to the documentation, so now many modules now feature quick links to the latest version of the source code. For example, the functools module documentation has a quick link at the top labeled:

Source code Lib/functools.py [https://github.com/python/cpython/tree/main/Lib/functools.py].

(Contributed by Raymond Hettinger; see rationale [https://rhettinger.wordpress.com/2011/01/28/open-your-source-more/].)

The docs now contain more examples and recipes. In particular, re module has an extensive section, 정규식 예제. Likewise, the itertools module continues to be updated with new Itertools 조리법.

The datetime module now has an auxiliary implementation in pure Python. No functionality was changed. This just provides an easier-to-read alternate implementation.

(Contributed by Alexander Belopolsky in bpo-9528 [https://bugs.python.org/issue?@action=redirect&bpo=9528].)

The unmaintained Demo directory has been removed. Some demos were integrated into the documentation, some were moved to the Tools/demo directory, and others were removed altogether.

(Contributed by Georg Brandl in bpo-7962 [https://bugs.python.org/issue?@action=redirect&bpo=7962].)

IDLE

The format menu now has an option to clean source files by stripping trailing whitespace.

(Contributed by Raymond Hettinger; bpo-5150 [https://bugs.python.org/issue?@action=redirect&bpo=5150].)

IDLE on Mac OS X now works with both Carbon AquaTk and Cocoa AquaTk.

(Contributed by Kevin Walzer, Ned Deily, and Ronald Oussoren; bpo-6075 [https://bugs.python.org/issue?@action=redirect&bpo=6075].)

Code Repository

In addition to the existing Subversion code repository at https://svn.python.org there is now a Mercurial [https://www.mercurial-scm.org/] repository at https://hg.python.org/.

After the 3.2 release, there are plans to switch to Mercurial as the primary repository. This distributed version control system should make it easier for members of the community to create and share external changesets. See PEP 385 [https://peps.python.org/pep-0385/] for details.

To learn to use the new version control system, see the Quick Start [https://www.mercurial-scm.org/wiki/QuickStart] or the Guide to Mercurial Workflows [https://www.mercurial-scm.org/guide].

Build and C API Changes

Changes to Python’s build process and to the C API include:

The idle, pydoc and 2to3 scripts are now installed with a version-specific suffix on make altinstall (bpo-10679 [https://bugs.python.org/issue?@action=redirect&bpo=10679]).

The C functions that access the Unicode Database now accept and return characters from the full Unicode range, even on narrow unicode builds (Py_UNICODE_TOLOWER, Py_UNICODE_ISDECIMAL, and others). A visible difference in Python is that unicodedata.numeric() now returns the correct value for large code points, and repr() may consider more characters as printable.

(Reported by Bupjoe Lee and fixed by Amaury Forgeot D’Arc; bpo-5127 [https://bugs.python.org/issue?@action=redirect&bpo=5127].)

Computed gotos are now enabled by default on supported compilers (which are detected by the configure script). They can still be disabled selectively by specifying --without-computed-gotos.

(Contributed by Antoine Pitrou; bpo-9203 [https://bugs.python.org/issue?@action=redirect&bpo=9203].)

The option --with-wctype-functions was removed. The built-in unicode database is now used for all functions.

(Contributed by Amaury Forgeot D’Arc; bpo-9210 [https://bugs.python.org/issue?@action=redirect&bpo=9210].)

Hash values are now values of a new type, Py_hash_t, which is defined to be the same size as a pointer. Previously they were of type long, which on some 64-bit operating systems is still only 32 bits long. As a result of this fix, set and dict can now hold more than 2**32 entries on builds with 64-bit pointers (previously, they could grow to that size but their performance degraded catastrophically).

(Suggested by Raymond Hettinger and implemented by Benjamin Peterson; bpo-9778 [https://bugs.python.org/issue?@action=redirect&bpo=9778].)

A new macro Py_VA_COPY copies the state of the variable argument list. It is equivalent to C99 va_copy but available on all Python platforms (bpo-2443 [https://bugs.python.org/issue?@action=redirect&bpo=2443]).

A new C API function PySys_SetArgvEx() allows an embedded interpreter to set sys.argv without also modifying sys.path (bpo-5753 [https://bugs.python.org/issue?@action=redirect&bpo=5753]).

PyEval_CallObject() is now only available in macro form. The function declaration, which was kept for backwards compatibility reasons, is now removed – the macro was introduced in 1997 (bpo-8276 [https://bugs.python.org/issue?@action=redirect&bpo=8276]).

There is a new function PyLong_AsLongLongAndOverflow() which is analogous to PyLong_AsLongAndOverflow(). They both serve to convert Python int into a native fixed-width type while providing detection of cases where the conversion won’t fit (bpo-7767 [https://bugs.python.org/issue?@action=redirect&bpo=7767]).

The PyUnicode_CompareWithASCIIString() function now returns not equal if the Python string is NUL terminated.

There is a new function PyErr_NewExceptionWithDoc() that is like PyErr_NewException() but allows a docstring to be specified. This lets C exceptions have the same self-documenting capabilities as their pure Python counterparts (bpo-7033 [https://bugs.python.org/issue?@action=redirect&bpo=7033]).

When compiled with the --with-valgrind option, the pymalloc allocator will be automatically disabled when running under Valgrind. This gives improved memory leak detection when running under Valgrind, while taking advantage of pymalloc at other times (bpo-2422 [https://bugs.python.org/issue?@action=redirect&bpo=2422]).

Removed the O? format from the PyArg_Parse functions. The format is no longer used and it had never been documented (bpo-8837 [https://bugs.python.org/issue?@action=redirect&bpo=8837]).

There were a number of other small changes to the C-API. See the Misc/NEWS [https://github.com/python/cpython/blob/v3.2.6/Misc/NEWS] file for a complete list.

Also, there were a number of updates to the Mac OS X build, see Mac/BuildScript/README.txt [https://github.com/python/cpython/blob/v3.2.6/Mac/BuildScript/README.txt] for details. For users running a 32/64-bit build, there is a known problem with the default Tcl/Tk on Mac OS X 10.6. Accordingly, we recommend installing an updated alternative such as ActiveState Tcl/Tk 8.5.9 [https://web.archive.org/web/20101208191259/https://www.activestate.com/activetcl/downloads]. See https://www.python.org/download/mac/tcltk/ for additional details.

Porting to Python 3.2

This section lists previously described changes and other bugfixes that may require changes to your code:

The configparser module has a number of clean-ups. The major change is to replace the old ConfigParser class with long-standing preferred alternative SafeConfigParser. In addition there are a number of smaller incompatibilities:

The interpolation syntax is now validated on get() and set() operations. In the default interpolation scheme, only two tokens with percent signs are valid: %(name)s and %%, the latter being an escaped percent sign.

The set() and add_section() methods now verify that values are actual strings. Formerly, unsupported types could be introduced unintentionally.

Duplicate sections or options from a single source now raise either DuplicateSectionError or DuplicateOptionError. Formerly, duplicates would silently overwrite a previous entry.

Inline comments are now disabled by default so now the ; character can be safely used in values.

Comments now can be indented. Consequently, for ; or # to appear at the start of a line in multiline values, it has to be interpolated. This keeps comment prefix characters in values from being mistaken as comments.

"" is now a valid value and is no longer automatically converted to an empty string. For empty strings, use "option =" in a line.

The nntplib module was reworked extensively, meaning that its APIs are often incompatible with the 3.1 APIs.

bytearray objects can no longer be used as filenames; instead, they should be converted to bytes.

The array.tostring() and array.fromstring() have been renamed to array.tobytes() and array.frombytes() for clarity. The old names have been deprecated. (See bpo-8990 [https://bugs.python.org/issue?@action=redirect&bpo=8990].)

PyArg_Parse*() functions:

“t#” format has been removed: use “s#” or “s*” instead

“w” and “w#” formats has been removed: use “w*” instead

The PyCObject type, deprecated in 3.1, has been removed. To wrap opaque C pointers in Python objects, the PyCapsule API should be used instead; the new type has a well-defined interface for passing typing safety information and a less complicated signature for calling a destructor.

The sys.setfilesystemencoding() function was removed because it had a flawed design.

The random.seed() function and method now salt string seeds with an sha512 hash function. To access the previous version of seed in order to reproduce Python 3.1 sequences, set the version argument to 1, random.seed(s, version=1).

The previously deprecated string.maketrans() function has been removed in favor of the static methods bytes.maketrans() and bytearray.maketrans(). This change solves the confusion around which types were supported by the string module. Now, str, bytes, and bytearray each have their own maketrans and translate methods with intermediate translation tables of the appropriate type.

(Contributed by Georg Brandl; bpo-5675 [https://bugs.python.org/issue?@action=redirect&bpo=5675].)

The previously deprecated contextlib.nested() function has been removed in favor of a plain with statement which can accept multiple context managers. The latter technique is faster (because it is built-in), and it does a better job finalizing multiple context managers when one of them raises an exception:

with open('mylog.txt') as infile, open('a.out', 'w') as outfile:
    for line in infile:
        if '<critical>' in line:
            outfile.write(line)

(Contributed by Georg Brandl and Mattias Brändström; appspot issue 53094 [https://codereview.appspot.com/53094].)

struct.pack() now only allows bytes for the s string pack code. Formerly, it would accept text arguments and implicitly encode them to bytes using UTF-8. This was problematic because it made assumptions about the correct encoding and because a variable-length encoding can fail when writing to fixed length segment of a structure.

Code such as struct.pack('<6sHHBBB', 'GIF87a', x, y) should be rewritten with to use bytes instead of text, struct.pack('<6sHHBBB', b'GIF87a', x, y).

(Discovered by David Beazley and fixed by Victor Stinner; bpo-10783 [https://bugs.python.org/issue?@action=redirect&bpo=10783].)

The xml.etree.ElementTree class now raises an xml.etree.ElementTree.ParseError when a parse fails. Previously it raised an xml.parsers.expat.ExpatError.

The new, longer str() value on floats may break doctests which rely on the old output format.

In subprocess.Popen, the default value for close_fds is now True under Unix; under Windows, it is True if the three standard streams are set to None, False otherwise. Previously, close_fds was always False by default, which produced difficult to solve bugs or race conditions when open file descriptors would leak into the child process.

Support for legacy HTTP 0.9 has been removed from urllib.request and http.client. Such support is still present on the server side (in http.server).

(Contributed by Antoine Pitrou, bpo-10711 [https://bugs.python.org/issue?@action=redirect&bpo=10711].)

SSL sockets in timeout mode now raise socket.timeout when a timeout occurs, rather than a generic SSLError.

(Contributed by Antoine Pitrou, bpo-10272 [https://bugs.python.org/issue?@action=redirect&bpo=10272].)

The misleading functions PyEval_AcquireLock() and PyEval_ReleaseLock() have been officially deprecated. The thread-state aware APIs (such as PyEval_SaveThread() and PyEval_RestoreThread()) should be used instead.

Due to security risks, asyncore.handle_accept() has been deprecated, and a new function, asyncore.handle_accepted(), was added to replace it.

(Contributed by Giampaolo Rodola in bpo-6706 [https://bugs.python.org/issue?@action=redirect&bpo=6706].)

Due to the new GIL implementation, PyEval_InitThreads() cannot be called before Py_Initialize() anymore.

What’s New In Python 3.1

Author:

Raymond Hettinger

This article explains the new features in Python 3.1, compared to 3.0. Python 3.1 was released on June 27, 2009.

PEP 372: Ordered Dictionaries

Regular Python dictionaries iterate over key/value pairs in arbitrary order. Over the years, a number of authors have written alternative implementations that remember the order that the keys were originally inserted. Based on the experiences from those implementations, a new collections.OrderedDict class has been introduced.

The OrderedDict API is substantially the same as regular dictionaries but will iterate over keys and values in a guaranteed order depending on when a key was first inserted. If a new entry overwrites an existing entry, the original insertion position is left unchanged. Deleting an entry and reinserting it will move it to the end.

The standard library now supports use of ordered dictionaries in several modules. The configparser module uses them by default. This lets configuration files be read, modified, and then written back in their original order. The _asdict() method for collections.namedtuple() now returns an ordered dictionary with the values appearing in the same order as the underlying tuple indices. The json module is being built-out with an object_pairs_hook to allow OrderedDicts to be built by the decoder. Support was also added for third-party tools like PyYAML [https://pyyaml.org/].

더 보기

PEP 372 [https://peps.python.org/pep-0372/] - Ordered Dictionaries

PEP written by Armin Ronacher and Raymond Hettinger. Implementation written by Raymond Hettinger.

Since an ordered dictionary remembers its insertion order, it can be used in conjunction with sorting to make a sorted dictionary:

>>> # regular unsorted dictionary
>>> d = {'banana': 3, 'apple':4, 'pear': 1, 'orange': 2}

>>> # dictionary sorted by key
>>> OrderedDict(sorted(d.items(), key=lambda t: t[0]))
OrderedDict([('apple', 4), ('banana', 3), ('orange', 2), ('pear', 1)])

>>> # dictionary sorted by value
>>> OrderedDict(sorted(d.items(), key=lambda t: t[1]))
OrderedDict([('pear', 1), ('orange', 2), ('banana', 3), ('apple', 4)])

>>> # dictionary sorted by length of the key string
>>> OrderedDict(sorted(d.items(), key=lambda t: len(t[0])))
OrderedDict([('pear', 1), ('apple', 4), ('orange', 2), ('banana', 3)])

The new sorted dictionaries maintain their sort order when entries are deleted. But when new keys are added, the keys are appended to the end and the sort is not maintained.

PEP 378: Format Specifier for Thousands Separator

The built-in format() function and the str.format() method use a mini-language that now includes a simple, non-locale aware way to format a number with a thousands separator. That provides a way to humanize a program’s output, improving its professional appearance and readability:

>>> format(1234567, ',d')
'1,234,567'
>>> format(1234567.89, ',.2f')
'1,234,567.89'
>>> format(12345.6 + 8901234.12j, ',f')
'12,345.600000+8,901,234.120000j'
>>> format(Decimal('1234567.89'), ',f')
'1,234,567.89'

The supported types are int, float, complex and decimal.Decimal.

Discussions are underway about how to specify alternative separators like dots, spaces, apostrophes, or underscores. Locale-aware applications should use the existing n format specifier which already has some support for thousands separators.

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PEP 378 [https://peps.python.org/pep-0378/] - Format Specifier for Thousands Separator

PEP written by Raymond Hettinger and implemented by Eric Smith and Mark Dickinson.

Other Language Changes

Some smaller changes made to the core Python language are:

Directories and zip archives containing a __main__.py file can now be executed directly by passing their name to the interpreter. The directory/zipfile is automatically inserted as the first entry in sys.path. (Suggestion and initial patch by Andy Chu; revised patch by Phillip J. Eby and Nick Coghlan; bpo-1739468 [https://bugs.python.org/issue?@action=redirect&bpo=1739468].)

The int() type gained a bit_length method that returns the number of bits necessary to represent its argument in binary:

>>> n = 37
>>> bin(37)
'0b100101'
>>> n.bit_length()
6
>>> n = 2**123-1
>>> n.bit_length()
123
>>> (n+1).bit_length()
124

(Contributed by Fredrik Johansson, Victor Stinner, Raymond Hettinger, and Mark Dickinson; bpo-3439 [https://bugs.python.org/issue?@action=redirect&bpo=3439].)

The fields in format() strings can now be automatically numbered:

>>> 'Sir {} of {}'.format('Gallahad', 'Camelot')
'Sir Gallahad of Camelot'

Formerly, the string would have required numbered fields such as: 'Sir {0} of {1}'.

(Contributed by Eric Smith; bpo-5237 [https://bugs.python.org/issue?@action=redirect&bpo=5237].)

The string.maketrans() function is deprecated and is replaced by new static methods, bytes.maketrans() and bytearray.maketrans(). This change solves the confusion around which types were supported by the string module. Now, str, bytes, and bytearray each have their own maketrans and translate methods with intermediate translation tables of the appropriate type.

(Contributed by Georg Brandl; bpo-5675 [https://bugs.python.org/issue?@action=redirect&bpo=5675].)

The syntax of the with statement now allows multiple context managers in a single statement:

>>> with open('mylog.txt') as infile, open('a.out', 'w') as outfile:
...     for line in infile:
...         if '<critical>' in line:
...             outfile.write(line)

With the new syntax, the contextlib.nested() function is no longer needed and is now deprecated.

(Contributed by Georg Brandl and Mattias Brändström; appspot issue 53094 [https://codereview.appspot.com/53094].)

round(x, n) now returns an integer if x is an integer. Previously it returned a float:

>>> round(1123, -2)
1100

(Contributed by Mark Dickinson; bpo-4707 [https://bugs.python.org/issue?@action=redirect&bpo=4707].)

Python now uses David Gay’s algorithm for finding the shortest floating-point representation that doesn’t change its value. This should help mitigate some of the confusion surrounding binary floating-point numbers.

The significance is easily seen with a number like 1.1 which does not have an exact equivalent in binary floating point. Since there is no exact equivalent, an expression like float('1.1') evaluates to the nearest representable value which is 0x1.199999999999ap+0 in hex or 1.100000000000000088817841970012523233890533447265625 in decimal. That nearest value was and still is used in subsequent floating-point calculations.

What is new is how the number gets displayed. Formerly, Python used a simple approach. The value of repr(1.1) was computed as format(1.1, '.17g') which evaluated to '1.1000000000000001'. The advantage of using 17 digits was that it relied on IEEE-754 guarantees to assure that eval(repr(1.1)) would round-trip exactly to its original value. The disadvantage is that many people found the output to be confusing (mistaking intrinsic limitations of binary floating-point representation as being a problem with Python itself).

The new algorithm for repr(1.1) is smarter and returns '1.1'. Effectively, it searches all equivalent string representations (ones that get stored with the same underlying float value) and returns the shortest representation.

The new algorithm tends to emit cleaner representations when possible, but it does not change the underlying values. So, it is still the case that 1.1 + 2.2 != 3.3 even though the representations may suggest otherwise.

The new algorithm depends on certain features in the underlying floating-point implementation. If the required features are not found, the old algorithm will continue to be used. Also, the text pickle protocols assure cross-platform portability by using the old algorithm.

(Contributed by Eric Smith and Mark Dickinson; bpo-1580 [https://bugs.python.org/issue?@action=redirect&bpo=1580])

New, Improved, and Deprecated Modules

Added a collections.Counter class to support convenient counting of unique items in a sequence or iterable:

>>> Counter(['red', 'blue', 'red', 'green', 'blue', 'blue'])
Counter({'blue': 3, 'red': 2, 'green': 1})

(Contributed by Raymond Hettinger; bpo-1696199 [https://bugs.python.org/issue?@action=redirect&bpo=1696199].)

Added a new module, tkinter.ttk for access to the Tk themed widget set. The basic idea of ttk is to separate, to the extent possible, the code implementing a widget’s behavior from the code implementing its appearance.

(Contributed by Guilherme Polo; bpo-2983 [https://bugs.python.org/issue?@action=redirect&bpo=2983].)

The gzip.GzipFile and bz2.BZ2File classes now support the context management protocol:

>>> # Automatically close file after writing
>>> with gzip.GzipFile(filename, "wb") as f:
...     f.write(b"xxx")

(Contributed by Antoine Pitrou.)

The decimal module now supports methods for creating a decimal object from a binary float. The conversion is exact but can sometimes be surprising:

>>> Decimal.from_float(1.1)
Decimal('1.100000000000000088817841970012523233890533447265625')

The long decimal result shows the actual binary fraction being stored for 1.1. The fraction has many digits because 1.1 cannot be exactly represented in binary.

(Contributed by Raymond Hettinger and Mark Dickinson.)

The itertools module grew two new functions. The itertools.combinations_with_replacement() function is one of four for generating combinatorics including permutations and Cartesian products. The itertools.compress() function mimics its namesake from APL. Also, the existing itertools.count() function now has an optional step argument and can accept any type of counting sequence including fractions.Fraction and decimal.Decimal:

>>> [p+q for p,q in combinations_with_replacement('LOVE', 2)]
['LL', 'LO', 'LV', 'LE', 'OO', 'OV', 'OE', 'VV', 'VE', 'EE']

>>> list(compress(data=range(10), selectors=[0,0,1,1,0,1,0,1,0,0]))
[2, 3, 5, 7]

>>> c = count(start=Fraction(1,2), step=Fraction(1,6))
>>> [next(c), next(c), next(c), next(c)]
[Fraction(1, 2), Fraction(2, 3), Fraction(5, 6), Fraction(1, 1)]

(Contributed by Raymond Hettinger.)

collections.namedtuple() now supports a keyword argument rename which lets invalid fieldnames be automatically converted to positional names in the form _0, _1, etc. This is useful when the field names are being created by an external source such as a CSV header, SQL field list, or user input:

>>> query = input()
SELECT region, dept, count(*) FROM main GROUPBY region, dept

>>> cursor.execute(query)
>>> query_fields = [desc[0] for desc in cursor.description]
>>> UserQuery = namedtuple('UserQuery', query_fields, rename=True)
>>> pprint.pprint([UserQuery(*row) for row in cursor])
[UserQuery(region='South', dept='Shipping', _2=185),
 UserQuery(region='North', dept='Accounting', _2=37),
 UserQuery(region='West', dept='Sales', _2=419)]

(Contributed by Raymond Hettinger; bpo-1818 [https://bugs.python.org/issue?@action=redirect&bpo=1818].)

The re.sub(), re.subn() and re.split() functions now accept a flags parameter.

(Contributed by Gregory Smith.)

The logging module now implements a simple logging.NullHandler class for applications that are not using logging but are calling library code that does. Setting-up a null handler will suppress spurious warnings such as “No handlers could be found for logger foo”:

>>> h = logging.NullHandler()
>>> logging.getLogger("foo").addHandler(h)

(Contributed by Vinay Sajip; bpo-4384 [https://bugs.python.org/issue?@action=redirect&bpo=4384]).

The runpy module which supports the -m command line switch now supports the execution of packages by looking for and executing a __main__ submodule when a package name is supplied.

(Contributed by Andi Vajda; bpo-4195 [https://bugs.python.org/issue?@action=redirect&bpo=4195].)

The pdb module can now access and display source code loaded via zipimport (or any other conformant PEP 302 [https://peps.python.org/pep-0302/] loader).

(Contributed by Alexander Belopolsky; bpo-4201 [https://bugs.python.org/issue?@action=redirect&bpo=4201].)

functools.partial objects can now be pickled.

(Suggested by Antoine Pitrou and Jesse Noller. Implemented by Jack Diederich; bpo-5228 [https://bugs.python.org/issue?@action=redirect&bpo=5228].)

Add pydoc help topics for symbols so that help('@') works as expected in the interactive environment.

(Contributed by David Laban; bpo-4739 [https://bugs.python.org/issue?@action=redirect&bpo=4739].)

The unittest module now supports skipping individual tests or classes of tests. And it supports marking a test as an expected failure, a test that is known to be broken, but shouldn’t be counted as a failure on a TestResult:

class TestGizmo(unittest.TestCase):

    @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
    def test_gizmo_on_windows(self):
        ...

    @unittest.expectedFailure
    def test_gimzo_without_required_library(self):
        ...

Also, tests for exceptions have been builtout to work with context managers using the with statement:

def test_division_by_zero(self):
    with self.assertRaises(ZeroDivisionError):
        x / 0

In addition, several new assertion methods were added including assertSetEqual(), assertDictEqual(), assertDictContainsSubset(), assertListEqual(), assertTupleEqual(), assertSequenceEqual(), assertRaisesRegexp(), assertIsNone(), and assertIsNotNone().

(Contributed by Benjamin Peterson and Antoine Pitrou.)

The io module has three new constants for the seek() method: SEEK_SET, SEEK_CUR, and SEEK_END.

The sys.version_info tuple is now a named tuple:

>>> sys.version_info
sys.version_info(major=3, minor=1, micro=0, releaselevel='alpha', serial=2)

(Contributed by Ross Light; bpo-4285 [https://bugs.python.org/issue?@action=redirect&bpo=4285].)

The nntplib and imaplib modules now support IPv6.

(Contributed by Derek Morr; bpo-1655 [https://bugs.python.org/issue?@action=redirect&bpo=1655] and bpo-1664 [https://bugs.python.org/issue?@action=redirect&bpo=1664].)

The pickle module has been adapted for better interoperability with Python 2.x when used with protocol 2 or lower. The reorganization of the standard library changed the formal reference for many objects. For example, __builtin__.set in Python 2 is called builtins.set in Python 3. This change confounded efforts to share data between different versions of Python. But now when protocol 2 or lower is selected, the pickler will automatically use the old Python 2 names for both loading and dumping. This remapping is turned-on by default but can be disabled with the fix_imports option:

>>> s = {1, 2, 3}
>>> pickle.dumps(s, protocol=0)
b'c__builtin__\nset\np0\n((lp1\nL1L\naL2L\naL3L\natp2\nRp3\n.'
>>> pickle.dumps(s, protocol=0, fix_imports=False)
b'cbuiltins\nset\np0\n((lp1\nL1L\naL2L\naL3L\natp2\nRp3\n.'

An unfortunate but unavoidable side-effect of this change is that protocol 2 pickles produced by Python 3.1 won’t be readable with Python 3.0. The latest pickle protocol, protocol 3, should be used when migrating data between Python 3.x implementations, as it doesn’t attempt to remain compatible with Python 2.x.

(Contributed by Alexandre Vassalotti and Antoine Pitrou, bpo-6137 [https://bugs.python.org/issue?@action=redirect&bpo=6137].)

A new module, importlib was added. It provides a complete, portable, pure Python reference implementation of the import statement and its counterpart, the __import__() function. It represents a substantial step forward in documenting and defining the actions that take place during imports.

(Contributed by Brett Cannon.)

Optimizations

Major performance enhancements have been added:

The new I/O library (as defined in PEP 3116 [https://peps.python.org/pep-3116/]) was mostly written in Python and quickly proved to be a problematic bottleneck in Python 3.0. In Python 3.1, the I/O library has been entirely rewritten in C and is 2 to 20 times faster depending on the task at hand. The pure Python version is still available for experimentation purposes through the _pyio module.

(Contributed by Amaury Forgeot d’Arc and Antoine Pitrou.)

Added a heuristic so that tuples and dicts containing only untrackable objects are not tracked by the garbage collector. This can reduce the size of collections and therefore the garbage collection overhead on long-running programs, depending on their particular use of datatypes.

(Contributed by Antoine Pitrou, bpo-4688 [https://bugs.python.org/issue?@action=redirect&bpo=4688].)

Enabling a configure option named --with-computed-gotos on compilers that support it (notably: gcc, SunPro, icc), the bytecode evaluation loop is compiled with a new dispatch mechanism which gives speedups of up to 20%, depending on the system, the compiler, and the benchmark.

(Contributed by Antoine Pitrou along with a number of other participants, bpo-4753 [https://bugs.python.org/issue?@action=redirect&bpo=4753]).

The decoding of UTF-8, UTF-16 and LATIN-1 is now two to four times faster.

(Contributed by Antoine Pitrou and Amaury Forgeot d’Arc, bpo-4868 [https://bugs.python.org/issue?@action=redirect&bpo=4868].)

The json module now has a C extension to substantially improve its performance. In addition, the API was modified so that json works only with str, not with bytes. That change makes the module closely match the JSON specification [https://json.org/] which is defined in terms of Unicode.

(Contributed by Bob Ippolito and converted to Py3.1 by Antoine Pitrou and Benjamin Peterson; bpo-4136 [https://bugs.python.org/issue?@action=redirect&bpo=4136].)

Unpickling now interns the attribute names of pickled objects. This saves memory and allows pickles to be smaller.

(Contributed by Jake McGuire and Antoine Pitrou; bpo-5084 [https://bugs.python.org/issue?@action=redirect&bpo=5084].)

IDLE

IDLE’s format menu now provides an option to strip trailing whitespace from a source file.

(Contributed by Roger D. Serwy; bpo-5150 [https://bugs.python.org/issue?@action=redirect&bpo=5150].)

Build and C API Changes

Changes to Python’s build process and to the C API include:

Integers are now stored internally either in base 2**15 or in base 2**30, the base being determined at build time. Previously, they were always stored in base 2**15. Using base 2**30 gives significant performance improvements on 64-bit machines, but benchmark results on 32-bit machines have been mixed. Therefore, the default is to use base 2**30 on 64-bit machines and base 2**15 on 32-bit machines; on Unix, there’s a new configure option --enable-big-digits that can be used to override this default.

Apart from the performance improvements this change should be invisible to end users, with one exception: for testing and debugging purposes there’s a new sys.int_info that provides information about the internal format, giving the number of bits per digit and the size in bytes of the C type used to store each digit:

>>> import sys
>>> sys.int_info
sys.int_info(bits_per_digit=30, sizeof_digit=4)

(Contributed by Mark Dickinson; bpo-4258 [https://bugs.python.org/issue?@action=redirect&bpo=4258].)

The PyLong_AsUnsignedLongLong() function now handles a negative pylong by raising OverflowError instead of TypeError.

(Contributed by Mark Dickinson and Lisandro Dalcrin; bpo-5175 [https://bugs.python.org/issue?@action=redirect&bpo=5175].)

Deprecated PyNumber_Int(). Use PyNumber_Long() instead.

(Contributed by Mark Dickinson; bpo-4910 [https://bugs.python.org/issue?@action=redirect&bpo=4910].)

Added a new PyOS_string_to_double() function to replace the deprecated functions PyOS_ascii_strtod() and PyOS_ascii_atof().

(Contributed by Mark Dickinson; bpo-5914 [https://bugs.python.org/issue?@action=redirect&bpo=5914].)

Added PyCapsule as a replacement for the PyCObject API. The principal difference is that the new type has a well defined interface for passing typing safety information and a less complicated signature for calling a destructor. The old type had a problematic API and is now deprecated.

(Contributed by Larry Hastings; bpo-5630 [https://bugs.python.org/issue?@action=redirect&bpo=5630].)

Porting to Python 3.1

This section lists previously described changes and other bugfixes that may require changes to your code:

The new floating-point string representations can break existing doctests. For example:

def e():
    '''Compute the base of natural logarithms.

    >>> e()
    2.7182818284590451

    '''
    return sum(1/math.factorial(x) for x in reversed(range(30)))

doctest.testmod()

**********************************************************************
Failed example:
    e()
Expected:
    2.7182818284590451
Got:
    2.718281828459045
**********************************************************************

The automatic name remapping in the pickle module for protocol 2 or lower can make Python 3.1 pickles unreadable in Python 3.0. One solution is to use protocol 3. Another solution is to set the fix_imports option to False. See the discussion above for more details.

What’s New In Python 3.0

Author:

Guido van Rossum

This article explains the new features in Python 3.0, compared to 2.6. Python 3.0, also known as “Python 3000” or “Py3K”, is the first ever intentionally backwards incompatible Python release. Python 3.0 was released on December 3, 2008. There are more changes than in a typical release, and more that are important for all Python users. Nevertheless, after digesting the changes, you’ll find that Python really hasn’t changed all that much – by and large, we’re mostly fixing well-known annoyances and warts, and removing a lot of old cruft.

This article doesn’t attempt to provide a complete specification of all new features, but instead tries to give a convenient overview. For full details, you should refer to the documentation for Python 3.0, and/or the many PEPs referenced in the text. If you want to understand the complete implementation and design rationale for a particular feature, PEPs usually have more details than the regular documentation; but note that PEPs usually are not kept up-to-date once a feature has been fully implemented.

Due to time constraints this document is not as complete as it should have been. As always for a new release, the Misc/NEWS file in the source distribution contains a wealth of detailed information about every small thing that was changed.

Common Stumbling Blocks

This section lists those few changes that are most likely to trip you up if you’re used to Python 2.5.

Print Is A Function

The print statement has been replaced with a print() function, with keyword arguments to replace most of the special syntax of the old print statement (PEP 3105 [https://peps.python.org/pep-3105/]). Examples:

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

Old: print x,           # Trailing comma suppresses newline
New: print(x, end=" ")  # Appends a space instead of a newline

Old: print              # Prints a newline
New: print()            # You must call the function!

Old: print >>sys.stderr, "fatal error"
New: print("fatal error", file=sys.stderr)

Old: print (x, y)       # prints repr((x, y))
New: print((x, y))      # Not the same as print(x, y)!

You can also customize the separator between items, e.g.:

print("There are <", 2**32, "> possibilities!", sep="")

which produces:

There are <4294967296> possibilities!

Note:

The print() function doesn’t support the “softspace” feature of the old print statement. For example, in Python 2.x, print "A\n", "B" would write "A\nB\n"; but in Python 3.0, print("A\n", "B") writes "A\n B\n".

Initially, you’ll be finding yourself typing the old print x a lot in interactive mode. Time to retrain your fingers to type print(x) instead!

When using the 2to3 source-to-source conversion tool, all print statements are automatically converted to print() function calls, so this is mostly a non-issue for larger projects.

Views And Iterators Instead Of Lists

Some well-known APIs no longer return lists:

dict methods dict.keys(), dict.items() and dict.values() return “views” instead of lists. For example, this no longer works: k = d.keys(); k.sort(). Use k = sorted(d) instead (this works in Python 2.5 too and is just as efficient).

Also, the dict.iterkeys(), dict.iteritems() and dict.itervalues() methods are no longer supported.

map() and filter() return iterators. If you really need a list and the input sequences are all of equal length, a quick fix is to wrap map() in list(), e.g. list(map(...)), but a better fix is often to use a list comprehension (especially when the original code uses lambda), or rewriting the code so it doesn’t need a list at all. Particularly tricky is map() invoked for the side effects of the function; the correct transformation is to use a regular for loop (since creating a list would just be wasteful).

If the input sequences are not of equal length, map() will stop at the termination of the shortest of the sequences. For full compatibility with map() from Python 2.x, also wrap the sequences in itertools.zip_longest(), e.g. map(func, *sequences) becomes list(map(func, itertools.zip_longest(*sequences))).

range() now behaves like xrange() used to behave, except it works with values of arbitrary size. The latter no longer exists.

zip() now returns an iterator.

Ordering Comparisons

Python 3.0 has simplified the rules for ordering comparisons:

The ordering comparison operators (<, <=, >=, >) raise a TypeError exception when the operands don’t have a meaningful natural ordering. Thus, expressions like 1 < '', 0 > None or len <= len are no longer valid, and e.g. None < None raises TypeError instead of returning False. A corollary is that sorting a heterogeneous list no longer makes sense – all the elements must be comparable to each other. Note that this does not apply to the == and != operators: objects of different incomparable types always compare unequal to each other.

builtin.sorted() and list.sort() no longer accept the cmp argument providing a comparison function. Use the key argument instead. N.B. the key and reverse arguments are now “keyword-only”.

The cmp() function should be treated as gone, and the __cmp__() special method is no longer supported. Use __lt__() for sorting, __eq__() with __hash__(), and other rich comparisons as needed. (If you really need the cmp() functionality, you could use the expression (a > b) - (a < b) as the equivalent for cmp(a, b).)

Integers

PEP 237 [https://peps.python.org/pep-0237/]: Essentially, long renamed to int. That is, there is only one built-in integral type, named int; but it behaves mostly like the old long type.

PEP 238 [https://peps.python.org/pep-0238/]: An expression like 1/2 returns a float. Use 1//2 to get the truncating behavior. (The latter syntax has existed for years, at least since Python 2.2.)

The sys.maxint constant was removed, since there is no longer a limit to the value of integers. However, sys.maxsize can be used as an integer larger than any practical list or string index. It conforms to the implementation’s “natural” integer size and is typically the same as sys.maxint in previous releases on the same platform (assuming the same build options).

The repr() of a long integer doesn’t include the trailing L anymore, so code that unconditionally strips that character will chop off the last digit instead. (Use str() instead.)

Octal literals are no longer of the form 0720; use 0o720 instead.

Text Vs. Data Instead Of Unicode Vs. 8-bit

Everything you thought you knew about binary data and Unicode has changed.

Python 3.0 uses the concepts of text and (binary) data instead of Unicode strings and 8-bit strings. All text is Unicode; however encoded Unicode is represented as binary data. The type used to hold text is str, the type used to hold data is bytes. The biggest difference with the 2.x situation is that any attempt to mix text and data in Python 3.0 raises TypeError, whereas if you were to mix Unicode and 8-bit strings in Python 2.x, it would work if the 8-bit string happened to contain only 7-bit (ASCII) bytes, but you would get UnicodeDecodeError if it contained non-ASCII values. This value-specific behavior has caused numerous sad faces over the years.

As a consequence of this change in philosophy, pretty much all code that uses Unicode, encodings or binary data most likely has to change. The change is for the better, as in the 2.x world there were numerous bugs having to do with mixing encoded and unencoded text. To be prepared in Python 2.x, start using unicode for all unencoded text, and str for binary or encoded data only. Then the 2to3 tool will do most of the work for you.

You can no longer use u"..." literals for Unicode text. However, you must use b"..." literals for binary data.

As the str and bytes types cannot be mixed, you must always explicitly convert between them. Use str.encode() to go from str to bytes, and bytes.decode() to go from bytes to str. You can also use bytes(s, encoding=...) and str(b, encoding=...), respectively.

Like str, the bytes type is immutable. There is a separate mutable type to hold buffered binary data, bytearray. Nearly all APIs that accept bytes also accept bytearray. The mutable API is based on collections.MutableSequence.

All backslashes in raw string literals are interpreted literally. This means that '\U' and '\u' escapes in raw strings are not treated specially. For example, r'\u20ac' is a string of 6 characters in Python 3.0, whereas in 2.6, ur'\u20ac' was the single “euro” character. (Of course, this change only affects raw string literals; the euro character is '\u20ac' in Python 3.0.)

The built-in basestring abstract type was removed. Use str instead. The str and bytes types don’t have functionality enough in common to warrant a shared base class. The 2to3 tool (see below) replaces every occurrence of basestring with str.

Files opened as text files (still the default mode for open()) always use an encoding to map between strings (in memory) and bytes (on disk). Binary files (opened with a b in the mode argument) always use bytes in memory. This means that if a file is opened using an incorrect mode or encoding, I/O will likely fail loudly, instead of silently producing incorrect data. It also means that even Unix users will have to specify the correct mode (text or binary) when opening a file. There is a platform-dependent default encoding, which on Unixy platforms can be set with the LANG environment variable (and sometimes also with some other platform-specific locale-related environment variables). In many cases, but not all, the system default is UTF-8; you should never count on this default. Any application reading or writing more than pure ASCII text should probably have a way to override the encoding. There is no longer any need for using the encoding-aware streams in the codecs module.

The initial values of sys.stdin, sys.stdout and sys.stderr are now unicode-only text files (i.e., they are instances of io.TextIOBase). To read and write bytes data with these streams, you need to use their io.TextIOBase.buffer attribute.

Filenames are passed to and returned from APIs as (Unicode) strings. This can present platform-specific problems because on some platforms filenames are arbitrary byte strings. (On the other hand, on Windows filenames are natively stored as Unicode.) As a work-around, most APIs (e.g. open() and many functions in the os module) that take filenames accept bytes objects as well as strings, and a few APIs have a way to ask for a bytes return value. Thus, os.listdir() returns a list of bytes instances if the argument is a bytes instance, and os.getcwdb() returns the current working directory as a bytes instance. Note that when os.listdir() returns a list of strings, filenames that cannot be decoded properly are omitted rather than raising UnicodeError.

Some system APIs like os.environ and sys.argv can also present problems when the bytes made available by the system is not interpretable using the default encoding. Setting the LANG variable and rerunning the program is probably the best approach.

PEP 3138 [https://peps.python.org/pep-3138/]: The repr() of a string no longer escapes non-ASCII characters. It still escapes control characters and code points with non-printable status in the Unicode standard, however.

PEP 3120 [https://peps.python.org/pep-3120/]: The default source encoding is now UTF-8.

PEP 3131 [https://peps.python.org/pep-3131/]: Non-ASCII letters are now allowed in identifiers. (However, the standard library remains ASCII-only with the exception of contributor names in comments.)

The StringIO and cStringIO modules are gone. Instead, import the io module and use io.StringIO or io.BytesIO for text and data respectively.

See also the 유니코드 HOWTO, which was updated for Python 3.0.

Overview Of Syntax Changes

This section gives a brief overview of every syntactic change in Python 3.0.

New Syntax

PEP 3107 [https://peps.python.org/pep-3107/]: Function argument and return value annotations. This provides a standardized way of annotating a function’s parameters and return value. There are no semantics attached to such annotations except that they can be introspected at runtime using the __annotations__ attribute. The intent is to encourage experimentation through metaclasses, decorators or frameworks.

PEP 3102 [https://peps.python.org/pep-3102/]: Keyword-only arguments. Named parameters occurring after *args in the parameter list must be specified using keyword syntax in the call. You can also use a bare * in the parameter list to indicate that you don’t accept a variable-length argument list, but you do have keyword-only arguments.

Keyword arguments are allowed after the list of base classes in a class definition. This is used by the new convention for specifying a metaclass (see next section), but can be used for other purposes as well, as long as the metaclass supports it.

PEP 3104 [https://peps.python.org/pep-3104/]: nonlocal statement. Using nonlocal x you can now assign directly to a variable in an outer (but non-global) scope. nonlocal is a new reserved word.

PEP 3132 [https://peps.python.org/pep-3132/]: Extended Iterable Unpacking. You can now write things like a, b, *rest = some_sequence. And even *rest, a = stuff. The rest object is always a (possibly empty) list; the right-hand side may be any iterable. Example:

(a, *rest, b) = range(5)

This sets a to 0, b to 4, and rest to [1, 2, 3].

Dictionary comprehensions: {k: v for k, v in stuff} means the same thing as dict(stuff) but is more flexible. (This is PEP 274 [https://peps.python.org/pep-0274/] vindicated. :-)

Set literals, e.g. {1, 2}. Note that {} is an empty dictionary; use set() for an empty set. Set comprehensions are also supported; e.g., {x for x in stuff} means the same thing as set(stuff) but is more flexible.

New octal literals, e.g. 0o720 (already in 2.6). The old octal literals (0720) are gone.

New binary literals, e.g. 0b1010 (already in 2.6), and there is a new corresponding built-in function, bin().

Bytes literals are introduced with a leading b or B, and there is a new corresponding built-in function, bytes().

Changed Syntax

PEP 3109 [https://peps.python.org/pep-3109/] and PEP 3134 [https://peps.python.org/pep-3134/]: new raise statement syntax: raise [expr [from expr]]. See below.

as and with are now reserved words. (Since 2.6, actually.)

True, False, and None are reserved words. (2.6 partially enforced the restrictions on None already.)

Change from except exc, var to except exc as var. See PEP 3110 [https://peps.python.org/pep-3110/].

PEP 3115 [https://peps.python.org/pep-3115/]: New Metaclass Syntax. Instead of:

class C:
    __metaclass__ = M
    ...

you must now use:

class C(metaclass=M):
    ...

The module-global __metaclass__ variable is no longer supported. (It was a crutch to make it easier to default to new-style classes without deriving every class from object.)

List comprehensions no longer support the syntactic form [... for var in item1, item2, ...]. Use [... for var in (item1, item2, ...)] instead. Also note that list comprehensions have different semantics: they are closer to syntactic sugar for a generator expression inside a list() constructor, and in particular the loop control variables are no longer leaked into the surrounding scope.

The ellipsis (...) can be used as an atomic expression anywhere. (Previously it was only allowed in slices.) Also, it must now be spelled as .... (Previously it could also be spelled as . . ., by a mere accident of the grammar.)

Removed Syntax

PEP 3113 [https://peps.python.org/pep-3113/]: Tuple parameter unpacking removed. You can no longer write def foo(a, (b, c)): .... Use def foo(a, b_c): b, c = b_c instead.

Removed backticks (use repr() instead).

Removed <> (use != instead).

Removed keyword: exec() is no longer a keyword; it remains as a function. (Fortunately the function syntax was also accepted in 2.x.) Also note that exec() no longer takes a stream argument; instead of exec(f) you can use exec(f.read()).

Integer literals no longer support a trailing l or L.

String literals no longer support a leading u or U.

The from module import * syntax is only allowed at the module level, no longer inside functions.

The only acceptable syntax for relative imports is from .[module] import name. All import forms not starting with . are interpreted as absolute imports. (PEP 328 [https://peps.python.org/pep-0328/])

Classic classes are gone.

Changes Already Present In Python 2.6

Since many users presumably make the jump straight from Python 2.5 to Python 3.0, this section reminds the reader of new features that were originally designed for Python 3.0 but that were back-ported to Python 2.6. The corresponding sections in What’s New in Python 2.6 should be consulted for longer descriptions.

PEP 343: The ‘with’ statement. The with statement is now a standard feature and no longer needs to be imported from the __future__. Also check out Writing Context Managers and The contextlib module.

PEP 366: Explicit Relative Imports From a Main Module. This enhances the usefulness of the -m option when the referenced module lives in a package.

PEP 370: Per-user site-packages Directory.

PEP 371: The multiprocessing Package.

PEP 3101: Advanced String Formatting. Note: the 2.6 description mentions the format() method for both 8-bit and Unicode strings. In 3.0, only the str type (text strings with Unicode support) supports this method; the bytes type does not. The plan is to eventually make this the only API for string formatting, and to start deprecating the % operator in Python 3.1.

PEP 3105: print As a Function. This is now a standard feature and no longer needs to be imported from __future__. More details were given above.

PEP 3110: Exception-Handling Changes. The except exc as var syntax is now standard and except exc, var is no longer supported. (Of course, the as var part is still optional.)

PEP 3112: Byte Literals. The b"..." string literal notation (and its variants like b'...', b"""...""", and br"...") now produces a literal of type bytes.

PEP 3116: New I/O Library. The io module is now the standard way of doing file I/O. The built-in open() function is now an alias for io.open() and has additional keyword arguments encoding, errors, newline and closefd. Also note that an invalid mode argument now raises ValueError, not IOError. The binary file object underlying a text file object can be accessed as f.buffer (but beware that the text object maintains a buffer of itself in order to speed up the encoding and decoding operations).

PEP 3118: Revised Buffer Protocol. The old builtin buffer() is now really gone; the new builtin memoryview() provides (mostly) similar functionality.

PEP 3119: Abstract Base Classes. The abc module and the ABCs defined in the collections module plays a somewhat more prominent role in the language now, and built-in collection types like dict and list conform to the collections.MutableMapping and collections.MutableSequence ABCs, respectively.

PEP 3127: Integer Literal Support and Syntax. As mentioned above, the new octal literal notation is the only one supported, and binary literals have been added.

PEP 3129: Class Decorators.

PEP 3141: A Type Hierarchy for Numbers. The numbers module is another new use of ABCs, defining Python’s “numeric tower”. Also note the new fractions module which implements numbers.Rational.

Library Changes

Due to time constraints, this document does not exhaustively cover the very extensive changes to the standard library. PEP 3108 [https://peps.python.org/pep-3108/] is the reference for the major changes to the library. Here’s a capsule review:

Many old modules were removed. Some, like gopherlib (no longer used) and md5 (replaced by hashlib), were already deprecated by PEP 4 [https://peps.python.org/pep-0004/]. Others were removed as a result of the removal of support for various platforms such as Irix, BeOS and Mac OS 9 (see PEP 11 [https://peps.python.org/pep-0011/]). Some modules were also selected for removal in Python 3.0 due to lack of use or because a better replacement exists. See PEP 3108 [https://peps.python.org/pep-3108/] for an exhaustive list.

The bsddb3 package was removed because its presence in the core standard library has proved over time to be a particular burden for the core developers due to testing instability and Berkeley DB’s release schedule. However, the package is alive and well, externally maintained at https://www.jcea.es/programacion/pybsddb.htm.

Some modules were renamed because their old name disobeyed PEP 8 [https://peps.python.org/pep-0008/], or for various other reasons. Here’s the list:

Old Name

New Name

_winreg

winreg

ConfigParser

configparser

copy_reg

copyreg

Queue

queue

SocketServer

socketserver

markupbase

_markupbase

repr

reprlib

test.test_support

test.support

A common pattern in Python 2.x is to have one version of a module implemented in pure Python, with an optional accelerated version implemented as a C extension; for example, pickle and cPickle. This places the burden of importing the accelerated version and falling back on the pure Python version on each user of these modules. In Python 3.0, the accelerated versions are considered implementation details of the pure Python versions. Users should always import the standard version, which attempts to import the accelerated version and falls back to the pure Python version. The pickle / cPickle pair received this treatment. The profile module is on the list for 3.1. The StringIO module has been turned into a class in the io module.

Some related modules have been grouped into packages, and usually the submodule names have been simplified. The resulting new packages are:

dbm (anydbm, dbhash, dbm, dumbdbm, gdbm, whichdb).

html (HTMLParser, htmlentitydefs).

http (httplib, BaseHTTPServer, CGIHTTPServer, SimpleHTTPServer, Cookie, cookielib).

tkinter (all Tkinter-related modules except turtle). The target audience of turtle doesn’t really care about tkinter. Also note that as of Python 2.6, the functionality of turtle has been greatly enhanced.

urllib (urllib, urllib2, urlparse, robotparse).

xmlrpc (xmlrpclib, DocXMLRPCServer, SimpleXMLRPCServer).

Some other changes to standard library modules, not covered by PEP 3108 [https://peps.python.org/pep-3108/]:

Killed sets. Use the built-in set() class.

Cleanup of the sys module: removed sys.exitfunc(), sys.exc_clear(), sys.exc_type, sys.exc_value, sys.exc_traceback. (Note that sys.last_type etc. remain.)

Cleanup of the array.array type: the read() and write() methods are gone; use fromfile() and tofile() instead. Also, the 'c' typecode for array is gone – use either 'b' for bytes or 'u' for Unicode characters.

Cleanup of the operator module: removed sequenceIncludes() and isCallable().

Cleanup of the thread module: acquire_lock() and release_lock() are gone; use acquire() and release() instead.

Cleanup of the random module: removed the jumpahead() API.

The new module is gone.

The functions os.tmpnam(), os.tempnam() and os.tmpfile() have been removed in favor of the tempfile module.

The tokenize module has been changed to work with bytes. The main entry point is now tokenize.tokenize(), instead of generate_tokens.

string.letters and its friends (string.lowercase and string.uppercase) are gone. Use string.ascii_letters etc. instead. (The reason for the removal is that string.letters and friends had locale-specific behavior, which is a bad idea for such attractively named global “constants”.)

Renamed module __builtin__ to builtins (removing the underscores, adding an ‘s’). The __builtins__ variable found in most global namespaces is unchanged. To modify a builtin, you should use builtins, not __builtins__!

PEP 3101 [https://peps.python.org/pep-3101/]: A New Approach To String Formatting

A new system for built-in string formatting operations replaces the % string formatting operator. (However, the % operator is still supported; it will be deprecated in Python 3.1 and removed from the language at some later time.) Read PEP 3101 [https://peps.python.org/pep-3101/] for the full scoop.

Changes To Exceptions

The APIs for raising and catching exception have been cleaned up and new powerful features added:

PEP 352 [https://peps.python.org/pep-0352/]: All exceptions must be derived (directly or indirectly) from BaseException. This is the root of the exception hierarchy. This is not new as a recommendation, but the requirement to inherit from BaseException is new. (Python 2.6 still allowed classic classes to be raised, and placed no restriction on what you can catch.) As a consequence, string exceptions are finally truly and utterly dead.

Almost all exceptions should actually derive from Exception; BaseException should only be used as a base class for exceptions that should only be handled at the top level, such as SystemExit or KeyboardInterrupt. The recommended idiom for handling all exceptions except for this latter category is to use except Exception.

StandardError was removed.

Exceptions no longer behave as sequences. Use the args attribute instead.

PEP 3109 [https://peps.python.org/pep-3109/]: Raising exceptions. You must now use raise Exception(args) instead of raise Exception, args. Additionally, you can no longer explicitly specify a traceback; instead, if you have to do this, you can assign directly to the __traceback__ attribute (see below).

PEP 3110 [https://peps.python.org/pep-3110/]: Catching exceptions. You must now use except SomeException as variable instead of except SomeException, variable. Moreover, the variable is explicitly deleted when the except block is left.

PEP 3134 [https://peps.python.org/pep-3134/]: Exception chaining. There are two cases: implicit chaining and explicit chaining. Implicit chaining happens when an exception is raised in an except or finally handler block. This usually happens due to a bug in the handler block; we call this a secondary exception. In this case, the original exception (that was being handled) is saved as the __context__ attribute of the secondary exception. Explicit chaining is invoked with this syntax:

raise SecondaryException() from primary_exception

(where primary_exception is any expression that produces an exception object, probably an exception that was previously caught). In this case, the primary exception is stored on the __cause__ attribute of the secondary exception. The traceback printed when an unhandled exception occurs walks the chain of __cause__ and __context__ attributes and prints a separate traceback for each component of the chain, with the primary exception at the top. (Java users may recognize this behavior.)

PEP 3134 [https://peps.python.org/pep-3134/]: Exception objects now store their traceback as the __traceback__ attribute. This means that an exception object now contains all the information pertaining to an exception, and there are fewer reasons to use sys.exc_info() (though the latter is not removed).

A few exception messages are improved when Windows fails to load an extension module. For example, error code 193 is now %1 is not a valid Win32 application. Strings now deal with non-English locales.

Miscellaneous Other Changes

Operators And Special Methods

!= now returns the opposite of ==, unless == returns NotImplemented.

The concept of “unbound methods” has been removed from the language. When referencing a method as a class attribute, you now get a plain function object.

__getslice__(), __setslice__() and __delslice__() were killed. The syntax a[i:j] now translates to a.__getitem__(slice(i, j)) (or __setitem__() or __delitem__(), when used as an assignment or deletion target, respectively).

PEP 3114 [https://peps.python.org/pep-3114/]: the standard next() method has been renamed to __next__().

The __oct__() and __hex__() special methods are removed – oct() and hex() use __index__() now to convert the argument to an integer.

Removed support for __members__ and __methods__.

The function attributes named func_X have been renamed to use the __X__ form, freeing up these names in the function attribute namespace for user-defined attributes. To wit, func_closure, func_code, func_defaults, func_dict, func_doc, func_globals, func_name were renamed to __closure__, __code__, __defaults__, __dict__, __doc__, __globals__, __name__, respectively.

__nonzero__() is now __bool__().

Builtins

PEP 3135 [https://peps.python.org/pep-3135/]: New super(). You can now invoke super() without arguments and (assuming this is in a regular instance method defined inside a class statement) the right class and instance will automatically be chosen. With arguments, the behavior of super() is unchanged.

PEP 3111 [https://peps.python.org/pep-3111/]: raw_input() was renamed to input(). That is, the new input() function reads a line from sys.stdin and returns it with the trailing newline stripped. It raises EOFError if the input is terminated prematurely. To get the old behavior of input(), use eval(input()).

A new built-in function next() was added to call the __next__() method on an object.

The round() function rounding strategy and return type have changed. Exact halfway cases are now rounded to the nearest even result instead of away from zero. (For example, round(2.5) now returns 2 rather than 3.) round(x[, n]) now delegates to x.__round__([n]) instead of always returning a float. It generally returns an integer when called with a single argument and a value of the same type as x when called with two arguments.

Moved intern() to sys.intern().

Removed: apply(). Instead of apply(f, args) use f(*args).

Removed callable(). Instead of callable(f) you can use isinstance(f, collections.Callable). The operator.isCallable() function is also gone.

Removed coerce(). This function no longer serves a purpose now that classic classes are gone.

Removed execfile(). Instead of execfile(fn) use exec(open(fn).read()).

Removed the file type. Use open(). There are now several different kinds of streams that open can return in the io module.

Removed reduce(). Use functools.reduce() if you really need it; however, 99 percent of the time an explicit for loop is more readable.

Removed reload(). Use imp.reload().

Removed. dict.has_key() – use the in operator instead.

Build and C API Changes

Due to time constraints, here is a very incomplete list of changes to the C API.

Support for several platforms was dropped, including but not limited to Mac OS 9, BeOS, RISCOS, Irix, and Tru64.

PEP 3118 [https://peps.python.org/pep-3118/]: New Buffer API.

PEP 3121 [https://peps.python.org/pep-3121/]: Extension Module Initialization & Finalization.

PEP 3123 [https://peps.python.org/pep-3123/]: Making PyObject_HEAD conform to standard C.

No more C API support for restricted execution.

PyNumber_Coerce(), PyNumber_CoerceEx(), PyMember_Get(), and PyMember_Set() C APIs are removed.

New C API PyImport_ImportModuleNoBlock(), works like PyImport_ImportModule() but won’t block on the import lock (returning an error instead).

Renamed the boolean conversion C-level slot and method: nb_nonzero is now nb_bool.

Removed METH_OLDARGS and WITH_CYCLE_GC from the C API.

Performance

The net result of the 3.0 generalizations is that Python 3.0 runs the pystone benchmark around 10% slower than Python 2.5. Most likely the biggest cause is the removal of special-casing for small integers. There’s room for improvement, but it will happen after 3.0 is released!

Porting To Python 3.0

For porting existing Python 2.5 or 2.6 source code to Python 3.0, the best strategy is the following:

(Prerequisite:) Start with excellent test coverage.

Port to Python 2.6. This should be no more work than the average port from Python 2.x to Python 2.(x+1). Make sure all your tests pass.

(Still using 2.6:) Turn on the -3 command line switch. This enables warnings about features that will be removed (or change) in 3.0. Run your test suite again, and fix code that you get warnings about until there are no warnings left, and all your tests still pass.

Run the 2to3 source-to-source translator over your source code tree. Run the result of the translation under Python 3.0. Manually fix up any remaining issues, fixing problems until all tests pass again.

It is not recommended to try to write source code that runs unchanged under both Python 2.6 and 3.0; you’d have to use a very contorted coding style, e.g. avoiding print statements, metaclasses, and much more. If you are maintaining a library that needs to support both Python 2.6 and Python 3.0, the best approach is to modify step 3 above by editing the 2.6 version of the source code and running the 2to3 translator again, rather than editing the 3.0 version of the source code.

For porting C extensions to Python 3.0, please see 확장 모듈을 파이썬 3에 이식하기.

What’s New in Python 2.7

Author:

A.M. Kuchling (amk at amk.ca)

This article explains the new features in Python 2.7. Python 2.7 was released on July 3, 2010.

Numeric handling has been improved in many ways, for both floating-point numbers and for the Decimal class. There are some useful additions to the standard library, such as a greatly enhanced unittest module, the argparse module for parsing command-line options, convenient OrderedDict and Counter classes in the collections module, and many other improvements.

Python 2.7 is planned to be the last of the 2.x releases, so we worked on making it a good release for the long term. To help with porting to Python 3, several new features from the Python 3.x series have been included in 2.7.

This article doesn’t attempt to provide a complete specification of the new features, but instead provides a convenient overview. For full details, you should refer to the documentation for Python 2.7 at https://docs.python.org. If you want to understand the rationale for the design and implementation, refer to the PEP for a particular new feature or the issue on https://bugs.python.org in which a change was discussed. Whenever possible, “What’s New in Python” links to the bug/patch item for each change.

The Future for Python 2.x

Python 2.7 is the last major release in the 2.x series, as the Python maintainers have shifted the focus of their new feature development efforts to the Python 3.x series. This means that while Python 2 continues to receive bug fixes, and to be updated to build correctly on new hardware and versions of supported operated systems, there will be no new full feature releases for the language or standard library.

However, while there is a large common subset between Python 2.7 and Python 3, and many of the changes involved in migrating to that common subset, or directly to Python 3, can be safely automated, some other changes (notably those associated with Unicode handling) may require careful consideration, and preferably robust automated regression test suites, to migrate effectively.

This means that Python 2.7 will remain in place for a long time, providing a stable and supported base platform for production systems that have not yet been ported to Python 3. The full expected lifecycle of the Python 2.7 series is detailed in PEP 373 [https://peps.python.org/pep-0373/].

Some key consequences of the long-term significance of 2.7 are:

As noted above, the 2.7 release has a much longer period of maintenance when compared to earlier 2.x versions. Python 2.7 is currently expected to remain supported by the core development team (receiving security updates and other bug fixes) until at least 2020 (10 years after its initial release, compared to the more typical support period of 18–24 months).

As the Python 2.7 standard library ages, making effective use of the Python Package Index (either directly or via a redistributor) becomes more important for Python 2 users. In addition to a wide variety of third party packages for various tasks, the available packages include backports of new modules and features from the Python 3 standard library that are compatible with Python 2, as well as various tools and libraries that can make it easier to migrate to Python 3. The Python Packaging User Guide [https://packaging.python.org] provides guidance on downloading and installing software from the Python Package Index.

While the preferred approach to enhancing Python 2 is now the publication of new packages on the Python Package Index, this approach doesn’t necessarily work in all cases, especially those related to network security. In exceptional cases that cannot be handled adequately by publishing new or updated packages on PyPI, the Python Enhancement Proposal process may be used to make the case for adding new features directly to the Python 2 standard library. Any such additions, and the maintenance releases where they were added, will be noted in the New Features Added to Python 2.7 Maintenance Releases section below.

For projects wishing to migrate from Python 2 to Python 3, or for library and framework developers wishing to support users on both Python 2 and Python 3, there are a variety of tools and guides available to help decide on a suitable approach and manage some of the technical details involved. The recommended starting point is the How to port Python 2 Code to Python 3 HOWTO guide.

Changes to the Handling of Deprecation Warnings

For Python 2.7, a policy decision was made to silence warnings only of interest to developers by default. DeprecationWarning and its descendants are now ignored unless otherwise requested, preventing users from seeing warnings triggered by an application. This change was also made in the branch that became Python 3.2. (Discussed on stdlib-sig and carried out in bpo-7319 [https://bugs.python.org/issue?@action=redirect&bpo=7319].)

In previous releases, DeprecationWarning messages were enabled by default, providing Python developers with a clear indication of where their code may break in a future major version of Python.

However, there are increasingly many users of Python-based applications who are not directly involved in the development of those applications. DeprecationWarning messages are irrelevant to such users, making them worry about an application that’s actually working correctly and burdening application developers with responding to these concerns.

You can re-enable display of DeprecationWarning messages by running Python with the -Wdefault (short form: -Wd) switch, or by setting the PYTHONWARNINGS environment variable to "default" (or "d") before running Python. Python code can also re-enable them by calling warnings.simplefilter('default').

The unittest module also automatically reenables deprecation warnings when running tests.

Python 3.1 Features

Much as Python 2.6 incorporated features from Python 3.0, version 2.7 incorporates some of the new features in Python 3.1. The 2.x series continues to provide tools for migrating to the 3.x series.

A partial list of 3.1 features that were backported to 2.7:

The syntax for set literals ({1,2,3} is a mutable set).

Dictionary and set comprehensions ({i: i*2 for i in range(3)}).

Multiple context managers in a single with statement.

A new version of the io library, rewritten in C for performance.

The ordered-dictionary type described in PEP 372: Adding an Ordered Dictionary to collections.

The new "," format specifier described in PEP 378: Format Specifier for Thousands Separator.

The memoryview object.

A small subset of the importlib module, described below.

The repr() of a float x is shorter in many cases: it’s now based on the shortest decimal string that’s guaranteed to round back to x. As in previous versions of Python, it’s guaranteed that float(repr(x)) recovers x.

Float-to-string and string-to-float conversions are correctly rounded. The round() function is also now correctly rounded.

The PyCapsule type, used to provide a C API for extension modules.

The PyLong_AsLongAndOverflow() C API function.

Other new Python3-mode warnings include:

operator.isCallable() and operator.sequenceIncludes(), which are not supported in 3.x, now trigger warnings.

The -3 switch now automatically enables the -Qwarn switch that causes warnings about using classic division with integers and long integers.

PEP 372: Adding an Ordered Dictionary to collections

Regular Python dictionaries iterate over key/value pairs in arbitrary order. Over the years, a number of authors have written alternative implementations that remember the order that the keys were originally inserted. Based on the experiences from those implementations, 2.7 introduces a new OrderedDict class in the collections module.

The OrderedDict API provides the same interface as regular dictionaries but iterates over keys and values in a guaranteed order depending on when a key was first inserted:

>>> from collections import OrderedDict
>>> d = OrderedDict([('first', 1),
...                  ('second', 2),
...                  ('third', 3)])
>>> d.items()
[('first', 1), ('second', 2), ('third', 3)]

If a new entry overwrites an existing entry, the original insertion position is left unchanged:

>>> d['second'] = 4
>>> d.items()
[('first', 1), ('second', 4), ('third', 3)]

Deleting an entry and reinserting it will move it to the end:

>>> del d['second']
>>> d['second'] = 5
>>> d.items()
[('first', 1), ('third', 3), ('second', 5)]

The popitem() method has an optional last argument that defaults to True. If last is true, the most recently added key is returned and removed; if it’s false, the oldest key is selected:

>>> od = OrderedDict([(x,0) for x in range(20)])
>>> od.popitem()
(19, 0)
>>> od.popitem()
(18, 0)
>>> od.popitem(last=False)
(0, 0)
>>> od.popitem(last=False)
(1, 0)

Comparing two ordered dictionaries checks both the keys and values, and requires that the insertion order was the same:

>>> od1 = OrderedDict([('first', 1),
...                    ('second', 2),
...                    ('third', 3)])
>>> od2 = OrderedDict([('third', 3),
...                    ('first', 1),
...                    ('second', 2)])
>>> od1 == od2
False
>>> # Move 'third' key to the end
>>> del od2['third']; od2['third'] = 3
>>> od1 == od2
True

Comparing an OrderedDict with a regular dictionary ignores the insertion order and just compares the keys and values.

How does the OrderedDict work? It maintains a doubly linked list of keys, appending new keys to the list as they’re inserted. A secondary dictionary maps keys to their corresponding list node, so deletion doesn’t have to traverse the entire linked list and therefore remains O(1).

The standard library now supports use of ordered dictionaries in several modules.

The ConfigParser module uses them by default, meaning that configuration files can now be read, modified, and then written back in their original order.

The _asdict() method for collections.namedtuple() now returns an ordered dictionary with the values appearing in the same order as the underlying tuple indices.

The json module’s JSONDecoder class constructor was extended with an object_pairs_hook parameter to allow OrderedDict instances to be built by the decoder. Support was also added for third-party tools like PyYAML [https://pyyaml.org/].

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PEP 372 [https://peps.python.org/pep-0372/] - Adding an ordered dictionary to collections

PEP written by Armin Ronacher and Raymond Hettinger; implemented by Raymond Hettinger.

PEP 378: Format Specifier for Thousands Separator

To make program output more readable, it can be useful to add separators to large numbers, rendering them as 18,446,744,073,709,551,616 instead of 18446744073709551616.

The fully general solution for doing this is the locale module, which can use different separators (“,” in North America, “.” in Europe) and different grouping sizes, but locale is complicated to use and unsuitable for multi-threaded applications where different threads are producing output for different locales.

Therefore, a simple comma-grouping mechanism has been added to the mini-language used by the str.format() method. When formatting a floating-point number, simply include a comma between the width and the precision:

>>> '{:20,.2f}'.format(18446744073709551616.0)
'18,446,744,073,709,551,616.00'

When formatting an integer, include the comma after the width:

>>> '{:20,d}'.format(18446744073709551616)
'18,446,744,073,709,551,616'

This mechanism is not adaptable at all; commas are always used as the separator and the grouping is always into three-digit groups. The comma-formatting mechanism isn’t as general as the locale module, but it’s easier to use.

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PEP 378 [https://peps.python.org/pep-0378/] - Format Specifier for Thousands Separator

PEP written by Raymond Hettinger; implemented by Eric Smith.

PEP 389: The argparse Module for Parsing Command Lines

The argparse module for parsing command-line arguments was added as a more powerful replacement for the optparse module.

This means Python now supports three different modules for parsing command-line arguments: getopt, optparse, and argparse. The getopt module closely resembles the C library’s getopt() function, so it remains useful if you’re writing a Python prototype that will eventually be rewritten in C. optparse becomes redundant, but there are no plans to remove it because there are many scripts still using it, and there’s no automated way to update these scripts. (Making the argparse API consistent with optparse’s interface was discussed but rejected as too messy and difficult.)

In short, if you’re writing a new script and don’t need to worry about compatibility with earlier versions of Python, use argparse instead of optparse.

Here’s an example:

import argparse

parser = argparse.ArgumentParser(description='Command-line example.')

# Add optional switches
parser.add_argument('-v', action='store_true', dest='is_verbose',
                    help='produce verbose output')
parser.add_argument('-o', action='store', dest='output',
                    metavar='FILE',
                    help='direct output to FILE instead of stdout')
parser.add_argument('-C', action='store', type=int, dest='context',
                    metavar='NUM', default=0,
                    help='display NUM lines of added context')

# Allow any number of additional arguments.
parser.add_argument(nargs='*', action='store', dest='inputs',
                    help='input filenames (default is stdin)')

args = parser.parse_args()
print args.__dict__

Unless you override it, -h and --help switches are automatically added, and produce neatly formatted output:

-> ./python.exe argparse-example.py --help
usage: argparse-example.py [-h] [-v] [-o FILE] [-C NUM] [inputs [inputs ...]]

Command-line example.

positional arguments:
  inputs      input filenames (default is stdin)

optional arguments:
  -h, --help  show this help message and exit
  -v          produce verbose output
  -o FILE     direct output to FILE instead of stdout
  -C NUM      display NUM lines of added context

As with optparse, the command-line switches and arguments are returned as an object with attributes named by the dest parameters:

-> ./python.exe argparse-example.py -v
{'output': None,
 'is_verbose': True,
 'context': 0,
 'inputs': []}

-> ./python.exe argparse-example.py -v -o /tmp/output -C 4 file1 file2
{'output': '/tmp/output',
 'is_verbose': True,
 'context': 4,
 'inputs': ['file1', 'file2']}

argparse has much fancier validation than optparse; you can specify an exact number of arguments as an integer, 0 or more arguments by passing '*', 1 or more by passing '+', or an optional argument with '?'. A top-level parser can contain sub-parsers to define subcommands that have different sets of switches, as in svn commit, svn checkout, etc. You can specify an argument’s type as FileType, which will automatically open files for you and understands that '-' means standard input or output.

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argparse documentation

The documentation page of the argparse module.

Upgrading optparse code

Part of the Python documentation, describing how to convert code that uses optparse.

PEP 389 [https://peps.python.org/pep-0389/] - argparse - New Command Line Parsing Module

PEP written and implemented by Steven Bethard.

PEP 391: Dictionary-Based Configuration For Logging

The logging module is very flexible; applications can define a tree of logging subsystems, and each logger in this tree can filter out certain messages, format them differently, and direct messages to a varying number of handlers.

All this flexibility can require a lot of configuration. You can write Python statements to create objects and set their properties, but a complex set-up requires verbose but boring code. logging also supports a fileConfig() function that parses a file, but the file format doesn’t support configuring filters, and it’s messier to generate programmatically.

Python 2.7 adds a dictConfig() function that uses a dictionary to configure logging. There are many ways to produce a dictionary from different sources: construct one with code; parse a file containing JSON; or use a YAML parsing library if one is installed. For more information see 구성 함수.

The following example configures two loggers, the root logger and a logger named “network”. Messages sent to the root logger will be sent to the system log using the syslog protocol, and messages to the “network” logger will be written to a network.log file that will be rotated once the log reaches 1MB.

import logging
import logging.config

configdict = {
 'version': 1,    # Configuration schema in use; must be 1 for now
 'formatters': {
     'standard': {
         'format': ('%(asctime)s %(name)-15s '
                    '%(levelname)-8s %(message)s')}},

 'handlers': {'netlog': {'backupCount': 10,
                     'class': 'logging.handlers.RotatingFileHandler',
                     'filename': '/logs/network.log',
                     'formatter': 'standard',
                     'level': 'INFO',
                     'maxBytes': 1000000},
              'syslog': {'class': 'logging.handlers.SysLogHandler',
                         'formatter': 'standard',
                         'level': 'ERROR'}},

 # Specify all the subordinate loggers
 'loggers': {
             'network': {
                         'handlers': ['netlog']
             }
 },
 # Specify properties of the root logger
 'root': {
          'handlers': ['syslog']
 },
}

# Set up configuration
logging.config.dictConfig(configdict)

# As an example, log two error messages
logger = logging.getLogger('/')
logger.error('Database not found')

netlogger = logging.getLogger('network')
netlogger.error('Connection failed')

Three smaller enhancements to the logging module, all implemented by Vinay Sajip, are:

The SysLogHandler class now supports syslogging over TCP. The constructor has a socktype parameter giving the type of socket to use, either socket.SOCK_DGRAM for UDP or socket.SOCK_STREAM for TCP. The default protocol remains UDP.

Logger instances gained a getChild() method that retrieves a descendant logger using a relative path. For example, once you retrieve a logger by doing log = getLogger('app'), calling log.getChild('network.listen') is equivalent to getLogger('app.network.listen').

The LoggerAdapter class gained an isEnabledFor() method that takes a level and returns whether the underlying logger would process a message of that level of importance.

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PEP 391 [https://peps.python.org/pep-0391/] - Dictionary-Based Configuration For Logging

PEP written and implemented by Vinay Sajip.

PEP 3106: Dictionary Views

The dictionary methods keys(), values(), and items() are different in Python 3.x. They return an object called a view instead of a fully materialized list.

It’s not possible to change the return values of keys(), values(), and items() in Python 2.7 because too much code would break. Instead the 3.x versions were added under the new names viewkeys(), viewvalues(), and viewitems().

>>> d = dict((i*10, chr(65+i)) for i in range(26))
>>> d
{0: 'A', 130: 'N', 10: 'B', 140: 'O', 20: ..., 250: 'Z'}
>>> d.viewkeys()
dict_keys([0, 130, 10, 140, 20, 150, 30, ..., 250])

Views can be iterated over, but the key and item views also behave like sets. The & operator performs intersection, and | performs a union:

>>> d1 = dict((i*10, chr(65+i)) for i in range(26))
>>> d2 = dict((i**.5, i) for i in range(1000))
>>> d1.viewkeys() & d2.viewkeys()
set([0.0, 10.0, 20.0, 30.0])
>>> d1.viewkeys() | range(0, 30)
set([0, 1, 130, 3, 4, 5, 6, ..., 120, 250])

The view keeps track of the dictionary and its contents change as the dictionary is modified:

>>> vk = d.viewkeys()
>>> vk
dict_keys([0, 130, 10, ..., 250])
>>> d[260] = '&'
>>> vk
dict_keys([0, 130, 260, 10, ..., 250])

However, note that you can’t add or remove keys while you’re iterating over the view:

>>> for k in vk:
...     d[k*2] = k
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: dictionary changed size during iteration

You can use the view methods in Python 2.x code, and the 2to3 converter will change them to the standard keys(), values(), and items() methods.

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PEP 3106 [https://peps.python.org/pep-3106/] - Revamping dict.keys(), .values() and .items()

PEP written by Guido van Rossum. Backported to 2.7 by Alexandre Vassalotti; bpo-1967 [https://bugs.python.org/issue?@action=redirect&bpo=1967].

PEP 3137: The memoryview Object

The memoryview object provides a view of another object’s memory content that matches the bytes type’s interface.

>>> import string
>>> m = memoryview(string.letters)
>>> m
<memory at 0x37f850>
>>> len(m)           # Returns length of underlying object
52
>>> m[0], m[25], m[26]   # Indexing returns one byte
('a', 'z', 'A')
>>> m2 = m[0:26]         # Slicing returns another memoryview
>>> m2
<memory at 0x37f080>

The content of the view can be converted to a string of bytes or a list of integers:

>>> m2.tobytes()
'abcdefghijklmnopqrstuvwxyz'
>>> m2.tolist()
[97, 98, 99, 100, 101, 102, 103, ... 121, 122]
>>>

memoryview objects allow modifying the underlying object if it’s a mutable object.

>>> m2[0] = 75
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot modify read-only memory
>>> b = bytearray(string.letters)  # Creating a mutable object
>>> b
bytearray(b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
>>> mb = memoryview(b)
>>> mb[0] = '*'         # Assign to view, changing the bytearray.
>>> b[0:5]              # The bytearray has been changed.
bytearray(b'*bcde')
>>>

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PEP 3137 [https://peps.python.org/pep-3137/] - Immutable Bytes and Mutable Buffer

PEP written by Guido van Rossum. Implemented by Travis Oliphant, Antoine Pitrou and others. Backported to 2.7 by Antoine Pitrou; bpo-2396 [https://bugs.python.org/issue?@action=redirect&bpo=2396].

Other Language Changes

Some smaller changes made to the core Python language are:

The syntax for set literals has been backported from Python 3.x. Curly brackets are used to surround the contents of the resulting mutable set; set literals are distinguished from dictionaries by not containing colons and values. {} continues to represent an empty dictionary; use set() for an empty set.

>>> {1, 2, 3, 4, 5}
set([1, 2, 3, 4, 5])
>>> set() # empty set
set([])
>>> {}    # empty dict
{}

Backported by Alexandre Vassalotti; bpo-2335 [https://bugs.python.org/issue?@action=redirect&bpo=2335].

Dictionary and set comprehensions are another feature backported from 3.x, generalizing list/generator comprehensions to use the literal syntax for sets and dictionaries.

>>> {x: x*x for x in range(6)}
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
>>> {('a'*x) for x in range(6)}
set(['', 'a', 'aa', 'aaa', 'aaaa', 'aaaaa'])

Backported by Alexandre Vassalotti; bpo-2333 [https://bugs.python.org/issue?@action=redirect&bpo=2333].

The with statement can now use multiple context managers in one statement. Context managers are processed from left to right and each one is treated as beginning a new with statement. This means that:

with A() as a, B() as b:
    ... suite of statements ...

is equivalent to:

with A() as a:
    with B() as b:
        ... suite of statements ...

The contextlib.nested() function provides a very similar function, so it’s no longer necessary and has been deprecated.

(Proposed in https://codereview.appspot.com/53094; implemented by Georg Brandl.)

Conversions between floating-point numbers and strings are now correctly rounded on most platforms. These conversions occur in many different places: str() on floats and complex numbers; the float and complex constructors; numeric formatting; serializing and deserializing floats and complex numbers using the marshal, pickle and json modules; parsing of float and imaginary literals in Python code; and Decimal-to-float conversion.

Related to this, the repr() of a floating-point number x now returns a result based on the shortest decimal string that’s guaranteed to round back to x under correct rounding (with round-half-to-even rounding mode). Previously it gave a string based on rounding x to 17 decimal digits.

The rounding library responsible for this improvement works on Windows and on Unix platforms using the gcc, icc, or suncc compilers. There may be a small number of platforms where correct operation of this code cannot be guaranteed, so the code is not used on such systems. You can find out which code is being used by checking sys.float_repr_style, which will be short if the new code is in use and legacy if it isn’t.

Implemented by Eric Smith and Mark Dickinson, using David Gay’s dtoa.c library; bpo-7117 [https://bugs.python.org/issue?@action=redirect&bpo=7117].

Conversions from long integers and regular integers to floating point now round differently, returning the floating-point number closest to the number. This doesn’t matter for small integers that can be converted exactly, but for large numbers that will unavoidably lose precision, Python 2.7 now approximates more closely. For example, Python 2.6 computed the following:

>>> n = 295147905179352891391
>>> float(n)
2.9514790517935283e+20
>>> n - long(float(n))
65535L

Python 2.7’s floating-point result is larger, but much closer to the true value:

>>> n = 295147905179352891391
>>> float(n)
2.9514790517935289e+20
>>> n - long(float(n))
-1L

(Implemented by Mark Dickinson; bpo-3166 [https://bugs.python.org/issue?@action=redirect&bpo=3166].)

Integer division is also more accurate in its rounding behaviours. (Also implemented by Mark Dickinson; bpo-1811 [https://bugs.python.org/issue?@action=redirect&bpo=1811].)

Implicit coercion for complex numbers has been removed; the interpreter will no longer ever attempt to call a __coerce__() method on complex objects. (Removed by Meador Inge and Mark Dickinson; bpo-5211 [https://bugs.python.org/issue?@action=redirect&bpo=5211].)

The str.format() method now supports automatic numbering of the replacement fields. This makes using str.format() more closely resemble using %s formatting:

>>> '{}:{}:{}'.format(2009, 04, 'Sunday')
'2009:4:Sunday'
>>> '{}:{}:{day}'.format(2009, 4, day='Sunday')
'2009:4:Sunday'

The auto-numbering takes the fields from left to right, so the first {...} specifier will use the first argument to str.format(), the next specifier will use the next argument, and so on. You can’t mix auto-numbering and explicit numbering – either number all of your specifier fields or none of them – but you can mix auto-numbering and named fields, as in the second example above. (Contributed by Eric Smith; bpo-5237 [https://bugs.python.org/issue?@action=redirect&bpo=5237].)

Complex numbers now correctly support usage with format(), and default to being right-aligned. Specifying a precision or comma-separation applies to both the real and imaginary parts of the number, but a specified field width and alignment is applied to the whole of the resulting 1.5+3j output. (Contributed by Eric Smith; bpo-1588 [https://bugs.python.org/issue?@action=redirect&bpo=1588] and bpo-7988 [https://bugs.python.org/issue?@action=redirect&bpo=7988].)

The ‘F’ format code now always formats its output using uppercase characters, so it will now produce ‘INF’ and ‘NAN’. (Contributed by Eric Smith; bpo-3382 [https://bugs.python.org/issue?@action=redirect&bpo=3382].)

A low-level change: the object.__format__() method now triggers a PendingDeprecationWarning if it’s passed a format string, because the __format__() method for object converts the object to a string representation and formats that. Previously the method silently applied the format string to the string representation, but that could hide mistakes in Python code. If you’re supplying formatting information such as an alignment or precision, presumably you’re expecting the formatting to be applied in some object-specific way. (Fixed by Eric Smith; bpo-7994 [https://bugs.python.org/issue?@action=redirect&bpo=7994].)

The int() and long() types gained a bit_length method that returns the number of bits necessary to represent its argument in binary:

>>> n = 37
>>> bin(n)
'0b100101'
>>> n.bit_length()
6
>>> n = 2**123-1
>>> n.bit_length()
123
>>> (n+1).bit_length()
124

(Contributed by Fredrik Johansson and Victor Stinner; bpo-3439 [https://bugs.python.org/issue?@action=redirect&bpo=3439].)

The import statement will no longer try an absolute import if a relative import (e.g. from .os import sep) fails. This fixes a bug, but could possibly break certain import statements that were only working by accident. (Fixed by Meador Inge; bpo-7902 [https://bugs.python.org/issue?@action=redirect&bpo=7902].)

It’s now possible for a subclass of the built-in unicode type to override the __unicode__() method. (Implemented by Victor Stinner; bpo-1583863 [https://bugs.python.org/issue?@action=redirect&bpo=1583863].)

The bytearray type’s translate() method now accepts None as its first argument. (Fixed by Georg Brandl; bpo-4759 [https://bugs.python.org/issue?@action=redirect&bpo=4759].)

When using @classmethod and @staticmethod to wrap methods as class or static methods, the wrapper object now exposes the wrapped function as their __func__ attribute. (Contributed by Amaury Forgeot d’Arc, after a suggestion by George Sakkis; bpo-5982 [https://bugs.python.org/issue?@action=redirect&bpo=5982].)

When a restricted set of attributes were set using __slots__, deleting an unset attribute would not raise AttributeError as you would expect. Fixed by Benjamin Peterson; bpo-7604 [https://bugs.python.org/issue?@action=redirect&bpo=7604].)

Two new encodings are now supported: “cp720”, used primarily for Arabic text; and “cp858”, a variant of CP 850 that adds the euro symbol. (CP720 contributed by Alexander Belchenko and Amaury Forgeot d’Arc in bpo-1616979 [https://bugs.python.org/issue?@action=redirect&bpo=1616979]; CP858 contributed by Tim Hatch in bpo-8016 [https://bugs.python.org/issue?@action=redirect&bpo=8016].)

The file object will now set the filename attribute on the IOError exception when trying to open a directory on POSIX platforms (noted by Jan Kaliszewski; bpo-4764 [https://bugs.python.org/issue?@action=redirect&bpo=4764]), and now explicitly checks for and forbids writing to read-only file objects instead of trusting the C library to catch and report the error (fixed by Stefan Krah; bpo-5677 [https://bugs.python.org/issue?@action=redirect&bpo=5677]).

The Python tokenizer now translates line endings itself, so the compile() built-in function now accepts code using any line-ending convention. Additionally, it no longer requires that the code end in a newline.

Extra parentheses in function definitions are illegal in Python 3.x, meaning that you get a syntax error from def f((x)): pass. In Python3-warning mode, Python 2.7 will now warn about this odd usage. (Noted by James Lingard; bpo-7362 [https://bugs.python.org/issue?@action=redirect&bpo=7362].)

It’s now possible to create weak references to old-style class objects. New-style classes were always weak-referenceable. (Fixed by Antoine Pitrou; bpo-8268 [https://bugs.python.org/issue?@action=redirect&bpo=8268].)

When a module object is garbage-collected, the module’s dictionary is now only cleared if no one else is holding a reference to the dictionary (bpo-7140 [https://bugs.python.org/issue?@action=redirect&bpo=7140]).

Interpreter Changes

A new environment variable, PYTHONWARNINGS, allows controlling warnings. It should be set to a string containing warning settings, equivalent to those used with the -W switch, separated by commas. (Contributed by Brian Curtin; bpo-7301 [https://bugs.python.org/issue?@action=redirect&bpo=7301].)

For example, the following setting will print warnings every time they occur, but turn warnings from the Cookie module into an error. (The exact syntax for setting an environment variable varies across operating systems and shells.)

export PYTHONWARNINGS=all,error:::Cookie:0

Optimizations

Several performance enhancements have been added:

A new opcode was added to perform the initial setup for with statements, looking up the __enter__() and __exit__() methods. (Contributed by Benjamin Peterson.)

The garbage collector now performs better for one common usage pattern: when many objects are being allocated without deallocating any of them. This would previously take quadratic time for garbage collection, but now the number of full garbage collections is reduced as the number of objects on the heap grows. The new logic only performs a full garbage collection pass when the middle generation has been collected 10 times and when the number of survivor objects from the middle generation exceeds 10% of the number of objects in the oldest generation. (Suggested by Martin von Löwis and implemented by Antoine Pitrou; bpo-4074 [https://bugs.python.org/issue?@action=redirect&bpo=4074].)

The garbage collector tries to avoid tracking simple containers which can’t be part of a cycle. In Python 2.7, this is now true for tuples and dicts containing atomic types (such as ints, strings, etc.). Transitively, a dict containing tuples of atomic types won’t be tracked either. This helps reduce the cost of each garbage collection by decreasing the number of objects to be considered and traversed by the collector. (Contributed by Antoine Pitrou; bpo-4688 [https://bugs.python.org/issue?@action=redirect&bpo=4688].)

Long integers are now stored internally either in base 2**15 or in base 2**30, the base being determined at build time. Previously, they were always stored in base 2**15. Using base 2**30 gives significant performance improvements on 64-bit machines, but benchmark results on 32-bit machines have been mixed. Therefore, the default is to use base 2**30 on 64-bit machines and base 2**15 on 32-bit machines; on Unix, there’s a new configure option --enable-big-digits that can be used to override this default.

Apart from the performance improvements this change should be invisible to end users, with one exception: for testing and debugging purposes there’s a new structseq sys.long_info that provides information about the internal format, giving the number of bits per digit and the size in bytes of the C type used to store each digit:

>>> import sys
>>> sys.long_info
sys.long_info(bits_per_digit=30, sizeof_digit=4)

(Contributed by Mark Dickinson; bpo-4258 [https://bugs.python.org/issue?@action=redirect&bpo=4258].)

Another set of changes made long objects a few bytes smaller: 2 bytes smaller on 32-bit systems and 6 bytes on 64-bit. (Contributed by Mark Dickinson; bpo-5260 [https://bugs.python.org/issue?@action=redirect&bpo=5260].)

The division algorithm for long integers has been made faster by tightening the inner loop, doing shifts instead of multiplications, and fixing an unnecessary extra iteration. Various benchmarks show speedups of between 50% and 150% for long integer divisions and modulo operations. (Contributed by Mark Dickinson; bpo-5512 [https://bugs.python.org/issue?@action=redirect&bpo=5512].) Bitwise operations are also significantly faster (initial patch by Gregory Smith; bpo-1087418 [https://bugs.python.org/issue?@action=redirect&bpo=1087418]).

The implementation of % checks for the left-side operand being a Python string and special-cases it; this results in a 1–3% performance increase for applications that frequently use % with strings, such as templating libraries. (Implemented by Collin Winter; bpo-5176 [https://bugs.python.org/issue?@action=redirect&bpo=5176].)

List comprehensions with an if condition are compiled into faster bytecode. (Patch by Antoine Pitrou, back-ported to 2.7 by Jeffrey Yasskin; bpo-4715 [https://bugs.python.org/issue?@action=redirect&bpo=4715].)

Converting an integer or long integer to a decimal string was made faster by special-casing base 10 instead of using a generalized conversion function that supports arbitrary bases. (Patch by Gawain Bolton; bpo-6713 [https://bugs.python.org/issue?@action=redirect&bpo=6713].)

The split(), replace(), rindex(), rpartition(), and rsplit() methods of string-like types (strings, Unicode strings, and bytearray objects) now use a fast reverse-search algorithm instead of a character-by-character scan. This is sometimes faster by a factor of 10. (Added by Florent Xicluna; bpo-7462 [https://bugs.python.org/issue?@action=redirect&bpo=7462] and bpo-7622 [https://bugs.python.org/issue?@action=redirect&bpo=7622].)

The pickle and cPickle modules now automatically intern the strings used for attribute names, reducing memory usage of the objects resulting from unpickling. (Contributed by Jake McGuire; bpo-5084 [https://bugs.python.org/issue?@action=redirect&bpo=5084].)

The cPickle module now special-cases dictionaries, nearly halving the time required to pickle them. (Contributed by Collin Winter; bpo-5670 [https://bugs.python.org/issue?@action=redirect&bpo=5670].)

New and Improved Modules

As in every release, Python’s standard library received a number of enhancements and bug fixes. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the Misc/NEWS file in the source tree for a more complete list of changes, or look through the Subversion logs for all the details.

The bdb module’s base debugging class Bdb gained a feature for skipping modules. The constructor now takes an iterable containing glob-style patterns such as django.*; the debugger will not step into stack frames from a module that matches one of these patterns. (Contributed by Maru Newby after a suggestion by Senthil Kumaran; bpo-5142 [https://bugs.python.org/issue?@action=redirect&bpo=5142].)

The binascii module now supports the buffer API, so it can be used with memoryview instances and other similar buffer objects. (Backported from 3.x by Florent Xicluna; bpo-7703 [https://bugs.python.org/issue?@action=redirect&bpo=7703].)

Updated module: the bsddb module has been updated from 4.7.2devel9 to version 4.8.4 of the pybsddb package [https://www.jcea.es/programacion/pybsddb.htm]. The new version features better Python 3.x compatibility, various bug fixes, and adds several new BerkeleyDB flags and methods. (Updated by Jesús Cea Avión; bpo-8156 [https://bugs.python.org/issue?@action=redirect&bpo=8156]. The pybsddb changelog can be read at https://hg.jcea.es/pybsddb/file/tip/ChangeLog.)

The bz2 module’s BZ2File now supports the context management protocol, so you can write with bz2.BZ2File(...) as f:. (Contributed by Hagen Fürstenau; bpo-3860 [https://bugs.python.org/issue?@action=redirect&bpo=3860].)

New class: the Counter class in the collections module is useful for tallying data. Counter instances behave mostly like dictionaries but return zero for missing keys instead of raising a KeyError:

>>> from collections import Counter
>>> c = Counter()
>>> for letter in 'here is a sample of english text':
...   c[letter] += 1
...
>>> c
Counter({' ': 6, 'e': 5, 's': 3, 'a': 2, 'i': 2, 'h': 2,
'l': 2, 't': 2, 'g': 1, 'f': 1, 'm': 1, 'o': 1, 'n': 1,
'p': 1, 'r': 1, 'x': 1})
>>> c['e']
5
>>> c['z']
0

There are three additional Counter methods. most_common() returns the N most common elements and their counts. elements() returns an iterator over the contained elements, repeating each element as many times as its count. subtract() takes an iterable and subtracts one for each element instead of adding; if the argument is a dictionary or another Counter, the counts are subtracted.

>>> c.most_common(5)
[(' ', 6), ('e', 5), ('s', 3), ('a', 2), ('i', 2)]
>>> c.elements() ->
   'a', 'a', ' ', ' ', ' ', ' ', ' ', ' ',
   'e', 'e', 'e', 'e', 'e', 'g', 'f', 'i', 'i',
   'h', 'h', 'm', 'l', 'l', 'o', 'n', 'p', 's',
   's', 's', 'r', 't', 't', 'x'
>>> c['e']
5
>>> c.subtract('very heavy on the letter e')
>>> c['e']    # Count is now lower
-1

Contributed by Raymond Hettinger; bpo-1696199 [https://bugs.python.org/issue?@action=redirect&bpo=1696199].

New class: OrderedDict is described in the earlier section PEP 372: Adding an Ordered Dictionary to collections.

New method: The deque data type now has a count() method that returns the number of contained elements equal to the supplied argument x, and a reverse() method that reverses the elements of the deque in-place. deque also exposes its maximum length as the read-only maxlen attribute. (Both features added by Raymond Hettinger.)

The namedtuple class now has an optional rename parameter. If rename is true, field names that are invalid because they’ve been repeated or aren’t legal Python identifiers will be renamed to legal names that are derived from the field’s position within the list of fields:

>>> from collections import namedtuple
>>> T = namedtuple('T', ['field1', '$illegal', 'for', 'field2'], rename=True)
>>> T._fields
('field1', '_1', '_2', 'field2')

(Added by Raymond Hettinger; bpo-1818 [https://bugs.python.org/issue?@action=redirect&bpo=1818].)

Finally, the Mapping abstract base class now returns NotImplemented if a mapping is compared to another type that isn’t a Mapping. (Fixed by Daniel Stutzbach; bpo-8729 [https://bugs.python.org/issue?@action=redirect&bpo=8729].)

Constructors for the parsing classes in the ConfigParser module now take an allow_no_value parameter, defaulting to false; if true, options without values will be allowed. For example:

>>> import ConfigParser, StringIO
>>> sample_config = """
... [mysqld]
... user = mysql
... pid-file = /var/run/mysqld/mysqld.pid
... skip-bdb
... """
>>> config = ConfigParser.RawConfigParser(allow_no_value=True)
>>> config.readfp(StringIO.StringIO(sample_config))
>>> config.get('mysqld', 'user')
'mysql'
>>> print config.get('mysqld', 'skip-bdb')
None
>>> print config.get('mysqld', 'unknown')
Traceback (most recent call last):
  ...
NoOptionError: No option 'unknown' in section: 'mysqld'

(Contributed by Mats Kindahl; bpo-7005 [https://bugs.python.org/issue?@action=redirect&bpo=7005].)

Deprecated function: contextlib.nested(), which allows handling more than one context manager with a single with statement, has been deprecated, because the with statement now supports multiple context managers.

The cookielib module now ignores cookies that have an invalid version field, one that doesn’t contain an integer value. (Fixed by John J. Lee; bpo-3924 [https://bugs.python.org/issue?@action=redirect&bpo=3924].)

The copy module’s deepcopy() function will now correctly copy bound instance methods. (Implemented by Robert Collins; bpo-1515 [https://bugs.python.org/issue?@action=redirect&bpo=1515].)

The ctypes module now always converts None to a C NULL pointer for arguments declared as pointers. (Changed by Thomas Heller; bpo-4606 [https://bugs.python.org/issue?@action=redirect&bpo=4606].) The underlying libffi library [https://sourceware.org/libffi/] has been updated to version 3.0.9, containing various fixes for different platforms. (Updated by Matthias Klose; bpo-8142 [https://bugs.python.org/issue?@action=redirect&bpo=8142].)

New method: the datetime module’s timedelta class gained a total_seconds() method that returns the number of seconds in the duration. (Contributed by Brian Quinlan; bpo-5788 [https://bugs.python.org/issue?@action=redirect&bpo=5788].)

New method: the Decimal class gained a from_float() class method that performs an exact conversion of a floating-point number to a Decimal. This exact conversion strives for the closest decimal approximation to the floating-point representation’s value; the resulting decimal value will therefore still include the inaccuracy, if any. For example, Decimal.from_float(0.1) returns Decimal('0.1000000000000000055511151231257827021181583404541015625'). (Implemented by Raymond Hettinger; bpo-4796 [https://bugs.python.org/issue?@action=redirect&bpo=4796].)

Comparing instances of Decimal with floating-point numbers now produces sensible results based on the numeric values of the operands. Previously such comparisons would fall back to Python’s default rules for comparing objects, which produced arbitrary results based on their type. Note that you still cannot combine Decimal and floating point in other operations such as addition, since you should be explicitly choosing how to convert between float and Decimal. (Fixed by Mark Dickinson; bpo-2531 [https://bugs.python.org/issue?@action=redirect&bpo=2531].)

The constructor for Decimal now accepts floating-point numbers (added by Raymond Hettinger; bpo-8257 [https://bugs.python.org/issue?@action=redirect&bpo=8257]) and non-European Unicode characters such as Arabic-Indic digits (contributed by Mark Dickinson; bpo-6595 [https://bugs.python.org/issue?@action=redirect&bpo=6595]).

Most of the methods of the Context class now accept integers as well as Decimal instances; the only exceptions are the canonical() and is_canonical() methods. (Patch by Juan José Conti; bpo-7633 [https://bugs.python.org/issue?@action=redirect&bpo=7633].)

When using Decimal instances with a string’s format() method, the default alignment was previously left-alignment. This has been changed to right-alignment, which is more sensible for numeric types. (Changed by Mark Dickinson; bpo-6857 [https://bugs.python.org/issue?@action=redirect&bpo=6857].)

Comparisons involving a signaling NaN value (or sNAN) now signal InvalidOperation instead of silently returning a true or false value depending on the comparison operator. Quiet NaN values (or NaN) are now hashable. (Fixed by Mark Dickinson; bpo-7279 [https://bugs.python.org/issue?@action=redirect&bpo=7279].)

The difflib module now produces output that is more compatible with modern diff/patch tools through one small change, using a tab character instead of spaces as a separator in the header giving the filename. (Fixed by Anatoly Techtonik; bpo-7585 [https://bugs.python.org/issue?@action=redirect&bpo=7585].)

The Distutils sdist command now always regenerates the MANIFEST file, since even if the MANIFEST.in or setup.py files haven’t been modified, the user might have created some new files that should be included. (Fixed by Tarek Ziadé; bpo-8688 [https://bugs.python.org/issue?@action=redirect&bpo=8688].)

The doctest module’s IGNORE_EXCEPTION_DETAIL flag will now ignore the name of the module containing the exception being tested. (Patch by Lennart Regebro; bpo-7490 [https://bugs.python.org/issue?@action=redirect&bpo=7490].)

The email module’s Message class will now accept a Unicode-valued payload, automatically converting the payload to the encoding specified by output_charset. (Added by R. David Murray; bpo-1368247 [https://bugs.python.org/issue?@action=redirect&bpo=1368247].)

The Fraction class now accepts a single float or Decimal instance, or two rational numbers, as arguments to its constructor. (Implemented by Mark Dickinson; rationals added in bpo-5812 [https://bugs.python.org/issue?@action=redirect&bpo=5812], and float/decimal in bpo-8294 [https://bugs.python.org/issue?@action=redirect&bpo=8294].)

Ordering comparisons (<, <=, >, >=) between fractions and complex numbers now raise a TypeError. This fixes an oversight, making the Fraction match the other numeric types.

New class: FTP_TLS in the ftplib module provides secure FTP connections using TLS encapsulation of authentication as well as subsequent control and data transfers. (Contributed by Giampaolo Rodola; bpo-2054 [https://bugs.python.org/issue?@action=redirect&bpo=2054].)

The storbinary() method for binary uploads can now restart uploads thanks to an added rest parameter (patch by Pablo Mouzo; bpo-6845 [https://bugs.python.org/issue?@action=redirect&bpo=6845].)

New class decorator: total_ordering() in the functools module takes a class that defines an __eq__() method and one of __lt__(), __le__(), __gt__(), or __ge__(), and generates the missing comparison methods. Since the __cmp__() method is being deprecated in Python 3.x, this decorator makes it easier to define ordered classes. (Added by Raymond Hettinger; bpo-5479 [https://bugs.python.org/issue?@action=redirect&bpo=5479].)

New function: cmp_to_key() will take an old-style comparison function that expects two arguments and return a new callable that can be used as the key parameter to functions such as sorted(), min() and max(), etc. The primary intended use is to help with making code compatible with Python 3.x. (Added by Raymond Hettinger.)

New function: the gc module’s is_tracked() returns true if a given instance is tracked by the garbage collector, false otherwise. (Contributed by Antoine Pitrou; bpo-4688 [https://bugs.python.org/issue?@action=redirect&bpo=4688].)

The gzip module’s GzipFile now supports the context management protocol, so you can write with gzip.GzipFile(...) as f: (contributed by Hagen Fürstenau; bpo-3860 [https://bugs.python.org/issue?@action=redirect&bpo=3860]), and it now implements the io.BufferedIOBase ABC, so you can wrap it with io.BufferedReader for faster processing (contributed by Nir Aides; bpo-7471 [https://bugs.python.org/issue?@action=redirect&bpo=7471]). It’s also now possible to override the modification time recorded in a gzipped file by providing an optional timestamp to the constructor. (Contributed by Jacques Frechet; bpo-4272 [https://bugs.python.org/issue?@action=redirect&bpo=4272].)

Files in gzip format can be padded with trailing zero bytes; the gzip module will now consume these trailing bytes. (Fixed by Tadek Pietraszek and Brian Curtin; bpo-2846 [https://bugs.python.org/issue?@action=redirect&bpo=2846].)

New attribute: the hashlib module now has an algorithms attribute containing a tuple naming the supported algorithms. In Python 2.7, hashlib.algorithms contains ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512'). (Contributed by Carl Chenet; bpo-7418 [https://bugs.python.org/issue?@action=redirect&bpo=7418].)

The default HTTPResponse class used by the httplib module now supports buffering, resulting in much faster reading of HTTP responses. (Contributed by Kristján Valur Jónsson; bpo-4879 [https://bugs.python.org/issue?@action=redirect&bpo=4879].)

The HTTPConnection and HTTPSConnection classes now support a source_address parameter, a (host, port) 2-tuple giving the source address that will be used for the connection. (Contributed by Eldon Ziegler; bpo-3972 [https://bugs.python.org/issue?@action=redirect&bpo=3972].)

The ihooks module now supports relative imports. Note that ihooks is an older module for customizing imports, superseded by the imputil module added in Python 2.0. (Relative import support added by Neil Schemenauer.)

The imaplib module now supports IPv6 addresses. (Contributed by Derek Morr; bpo-1655 [https://bugs.python.org/issue?@action=redirect&bpo=1655].)

New function: the inspect module’s getcallargs() takes a callable and its positional and keyword arguments, and figures out which of the callable’s parameters will receive each argument, returning a dictionary mapping argument names to their values. For example:

>>> from inspect import getcallargs
>>> def f(a, b=1, *pos, **named):
...     pass
...
>>> getcallargs(f, 1, 2, 3)
{'a': 1, 'b': 2, 'pos': (3,), 'named': {}}
>>> getcallargs(f, a=2, x=4)
{'a': 2, 'b': 1, 'pos': (), 'named': {'x': 4}}
>>> getcallargs(f)
Traceback (most recent call last):
...
TypeError: f() takes at least 1 argument (0 given)

Contributed by George Sakkis; bpo-3135 [https://bugs.python.org/issue?@action=redirect&bpo=3135].

Updated module: The io library has been upgraded to the version shipped with Python 3.1. For 3.1, the I/O library was entirely rewritten in C and is 2 to 20 times faster depending on the task being performed. The original Python version was renamed to the _pyio module.

One minor resulting change: the io.TextIOBase class now has an errors attribute giving the error setting used for encoding and decoding errors (one of 'strict', 'replace', 'ignore').

The io.FileIO class now raises an OSError when passed an invalid file descriptor. (Implemented by Benjamin Peterson; bpo-4991 [https://bugs.python.org/issue?@action=redirect&bpo=4991].) The truncate() method now preserves the file position; previously it would change the file position to the end of the new file. (Fixed by Pascal Chambon; bpo-6939 [https://bugs.python.org/issue?@action=redirect&bpo=6939].)

New function: itertools.compress(data, selectors) takes two iterators. Elements of data are returned if the corresponding value in selectors is true:

itertools.compress('ABCDEF', [1,0,1,0,1,1]) =>
  A, C, E, F

New function: itertools.combinations_with_replacement(iter, r) returns all the possible r-length combinations of elements from the iterable iter. Unlike combinations(), individual elements can be repeated in the generated combinations:

itertools.combinations_with_replacement('abc', 2) =>
  ('a', 'a'), ('a', 'b'), ('a', 'c'),
  ('b', 'b'), ('b', 'c'), ('c', 'c')

Note that elements are treated as unique depending on their position in the input, not their actual values.

The itertools.count() function now has a step argument that allows incrementing by values other than 1. count() also now allows keyword arguments, and using non-integer values such as floats or Decimal instances. (Implemented by Raymond Hettinger; bpo-5032 [https://bugs.python.org/issue?@action=redirect&bpo=5032].)

itertools.combinations() and itertools.product() previously raised ValueError for values of r larger than the input iterable. This was deemed a specification error, so they now return an empty iterator. (Fixed by Raymond Hettinger; bpo-4816 [https://bugs.python.org/issue?@action=redirect&bpo=4816].)

Updated module: The json module was upgraded to version 2.0.9 of the simplejson package, which includes a C extension that makes encoding and decoding faster. (Contributed by Bob Ippolito; bpo-4136 [https://bugs.python.org/issue?@action=redirect&bpo=4136].)

To support the new collections.OrderedDict type, json.load() now has an optional object_pairs_hook parameter that will be called with any object literal that decodes to a list of pairs. (Contributed by Raymond Hettinger; bpo-5381 [https://bugs.python.org/issue?@action=redirect&bpo=5381].)

The mailbox module’s Maildir class now records the timestamp on the directories it reads, and only re-reads them if the modification time has subsequently changed. This improves performance by avoiding unneeded directory scans. (Fixed by A.M. Kuchling and Antoine Pitrou; bpo-1607951 [https://bugs.python.org/issue?@action=redirect&bpo=1607951], bpo-6896 [https://bugs.python.org/issue?@action=redirect&bpo=6896].)

New functions: the math module gained erf() and erfc() for the error function and the complementary error function, expm1() which computes e**x - 1 with more precision than using exp() and subtracting 1, gamma() for the Gamma function, and lgamma() for the natural log of the Gamma function. (Contributed by Mark Dickinson and nirinA raseliarison; bpo-3366 [https://bugs.python.org/issue?@action=redirect&bpo=3366].)

The multiprocessing module’s Manager* classes can now be passed a callable that will be called whenever a subprocess is started, along with a set of arguments that will be passed to the callable. (Contributed by lekma; bpo-5585 [https://bugs.python.org/issue?@action=redirect&bpo=5585].)

The Pool class, which controls a pool of worker processes, now has an optional maxtasksperchild parameter. Worker processes will perform the specified number of tasks and then exit, causing the Pool to start a new worker. This is useful if tasks may leak memory or other resources, or if some tasks will cause the worker to become very large. (Contributed by Charles Cazabon; bpo-6963 [https://bugs.python.org/issue?@action=redirect&bpo=6963].)

The nntplib module now supports IPv6 addresses. (Contributed by Derek Morr; bpo-1664 [https://bugs.python.org/issue?@action=redirect&bpo=1664].)

New functions: the os module wraps the following POSIX system calls: getresgid() and getresuid(), which return the real, effective, and saved GIDs and UIDs; setresgid() and setresuid(), which set real, effective, and saved GIDs and UIDs to new values; initgroups(), which initialize the group access list for the current process. (GID/UID functions contributed by Travis H.; bpo-6508 [https://bugs.python.org/issue?@action=redirect&bpo=6508]. Support for initgroups added by Jean-Paul Calderone; bpo-7333 [https://bugs.python.org/issue?@action=redirect&bpo=7333].)

The os.fork() function now re-initializes the import lock in the child process; this fixes problems on Solaris when fork() is called from a thread. (Fixed by Zsolt Cserna; bpo-7242 [https://bugs.python.org/issue?@action=redirect&bpo=7242].)

In the os.path module, the normpath() and abspath() functions now preserve Unicode; if their input path is a Unicode string, the return value is also a Unicode string. (normpath() fixed by Matt Giuca in bpo-5827 [https://bugs.python.org/issue?@action=redirect&bpo=5827]; abspath() fixed by Ezio Melotti in bpo-3426 [https://bugs.python.org/issue?@action=redirect&bpo=3426].)

The pydoc module now has help for the various symbols that Python uses. You can now do help('<<') or help('@'), for example. (Contributed by David Laban; bpo-4739 [https://bugs.python.org/issue?@action=redirect&bpo=4739].)

The re module’s split(), sub(), and subn() now accept an optional flags argument, for consistency with the other functions in the module. (Added by Gregory P. Smith.)

New function: run_path() in the runpy module will execute the code at a provided path argument. path can be the path of a Python source file (example.py), a compiled bytecode file (example.pyc), a directory (./package/), or a zip archive (example.zip). If a directory or zip path is provided, it will be added to the front of sys.path and the module __main__ will be imported. It’s expected that the directory or zip contains a __main__.py; if it doesn’t, some other __main__.py might be imported from a location later in sys.path. This makes more of the machinery of runpy available to scripts that want to mimic the way Python’s command line processes an explicit path name. (Added by Nick Coghlan; bpo-6816 [https://bugs.python.org/issue?@action=redirect&bpo=6816].)

New function: in the shutil module, make_archive() takes a filename, archive type (zip or tar-format), and a directory path, and creates an archive containing the directory’s contents. (Added by Tarek Ziadé.)

shutil’s copyfile() and copytree() functions now raise a SpecialFileError exception when asked to copy a named pipe. Previously the code would treat named pipes like a regular file by opening them for reading, and this would block indefinitely. (Fixed by Antoine Pitrou; bpo-3002 [https://bugs.python.org/issue?@action=redirect&bpo=3002].)

The signal module no longer re-installs the signal handler unless this is truly necessary, which fixes a bug that could make it impossible to catch the EINTR signal robustly. (Fixed by Charles-Francois Natali; bpo-8354 [https://bugs.python.org/issue?@action=redirect&bpo=8354].)

New functions: in the site module, three new functions return various site- and user-specific paths. getsitepackages() returns a list containing all global site-packages directories, getusersitepackages() returns the path of the user’s site-packages directory, and getuserbase() returns the value of the USER_BASE environment variable, giving the path to a directory that can be used to store data. (Contributed by Tarek Ziadé; bpo-6693 [https://bugs.python.org/issue?@action=redirect&bpo=6693].)

The site module now reports exceptions occurring when the sitecustomize module is imported, and will no longer catch and swallow the KeyboardInterrupt exception. (Fixed by Victor Stinner; bpo-3137 [https://bugs.python.org/issue?@action=redirect&bpo=3137].)

The create_connection() function gained a source_address parameter, a (host, port) 2-tuple giving the source address that will be used for the connection. (Contributed by Eldon Ziegler; bpo-3972 [https://bugs.python.org/issue?@action=redirect&bpo=3972].)

The recv_into() and recvfrom_into() methods will now write into objects that support the buffer API, most usefully the bytearray and memoryview objects. (Implemented by Antoine Pitrou; bpo-8104 [https://bugs.python.org/issue?@action=redirect&bpo=8104].)

The SocketServer module’s TCPServer class now supports socket timeouts and disabling the Nagle algorithm. The disable_nagle_algorithm class attribute defaults to False; if overridden to be true, new request connections will have the TCP_NODELAY option set to prevent buffering many small sends into a single TCP packet. The timeout class attribute can hold a timeout in seconds that will be applied to the request socket; if no request is received within that time, handle_timeout() will be called and handle_request() will return. (Contributed by Kristján Valur Jónsson; bpo-6192 [https://bugs.python.org/issue?@action=redirect&bpo=6192] and bpo-6267 [https://bugs.python.org/issue?@action=redirect&bpo=6267].)

Updated module: the sqlite3 module has been updated to version 2.6.0 of the pysqlite package [https://github.com/ghaering/pysqlite]. Version 2.6.0 includes a number of bugfixes, and adds the ability to load SQLite extensions from shared libraries. Call the enable_load_extension(True) method to enable extensions, and then call load_extension() to load a particular shared library. (Updated by Gerhard Häring.)

The ssl module’s SSLSocket objects now support the buffer API, which fixed a test suite failure (fix by Antoine Pitrou; bpo-7133 [https://bugs.python.org/issue?@action=redirect&bpo=7133]) and automatically set OpenSSL’s SSL_MODE_AUTO_RETRY, which will prevent an error code being returned from recv() operations that trigger an SSL renegotiation (fix by Antoine Pitrou; bpo-8222 [https://bugs.python.org/issue?@action=redirect&bpo=8222]).

The wrap_socket() constructor function now takes a ciphers argument that’s a string listing the encryption algorithms to be allowed; the format of the string is described in the OpenSSL documentation [https://docs.openssl.org/1.0.2/man1/ciphers/]. (Added by Antoine Pitrou; bpo-8322 [https://bugs.python.org/issue?@action=redirect&bpo=8322].)

Another change makes the extension load all of OpenSSL’s ciphers and digest algorithms so that they’re all available. Some SSL certificates couldn’t be verified, reporting an “unknown algorithm” error. (Reported by Beda Kosata, and fixed by Antoine Pitrou; bpo-8484 [https://bugs.python.org/issue?@action=redirect&bpo=8484].)

The version of OpenSSL being used is now available as the module attributes ssl.OPENSSL_VERSION (a string), ssl.OPENSSL_VERSION_INFO (a 5-tuple), and ssl.OPENSSL_VERSION_NUMBER (an integer). (Added by Antoine Pitrou; bpo-8321 [https://bugs.python.org/issue?@action=redirect&bpo=8321].)

The struct module will no longer silently ignore overflow errors when a value is too large for a particular integer format code (one of bBhHiIlLqQ); it now always raises a struct.error exception. (Changed by Mark Dickinson; bpo-1523 [https://bugs.python.org/issue?@action=redirect&bpo=1523].) The pack() function will also attempt to use __index__() to convert and pack non-integers before trying the __int__() method or reporting an error. (Changed by Mark Dickinson; bpo-8300 [https://bugs.python.org/issue?@action=redirect&bpo=8300].)

New function: the subprocess module’s check_output() runs a command with a specified set of arguments and returns the command’s output as a string when the command runs without error, or raises a CalledProcessError exception otherwise.

>>> subprocess.check_output(['df', '-h', '.'])
'Filesystem     Size   Used  Avail Capacity  Mounted on\n
/dev/disk0s2    52G    49G   3.0G    94%    /\n'

>>> subprocess.check_output(['df', '-h', '/bogus'])
  ...
subprocess.CalledProcessError: Command '['df', '-h', '/bogus']' returned non-zero exit status 1

(Contributed by Gregory P. Smith.)

The subprocess module will now retry its internal system calls on receiving an EINTR signal. (Reported by several people; final patch by Gregory P. Smith in bpo-1068268 [https://bugs.python.org/issue?@action=redirect&bpo=1068268].)

New function: is_declared_global() in the symtable module returns true for variables that are explicitly declared to be global, false for ones that are implicitly global. (Contributed by Jeremy Hylton.)

The syslog module will now use the value of sys.argv[0] as the identifier instead of the previous default value of 'python'. (Changed by Sean Reifschneider; bpo-8451 [https://bugs.python.org/issue?@action=redirect&bpo=8451].)

The sys.version_info value is now a named tuple, with attributes named major, minor, micro, releaselevel, and serial. (Contributed by Ross Light; bpo-4285 [https://bugs.python.org/issue?@action=redirect&bpo=4285].)

sys.getwindowsversion() also returns a named tuple, with attributes named major, minor, build, platform, service_pack, service_pack_major, service_pack_minor, suite_mask, and product_type. (Contributed by Brian Curtin; bpo-7766 [https://bugs.python.org/issue?@action=redirect&bpo=7766].)

The tarfile module’s default error handling has changed, to no longer suppress fatal errors. The default error level was previously 0, which meant that errors would only result in a message being written to the debug log, but because the debug log is not activated by default, these errors go unnoticed. The default error level is now 1, which raises an exception if there’s an error. (Changed by Lars Gustäbel; bpo-7357 [https://bugs.python.org/issue?@action=redirect&bpo=7357].)

tarfile now supports filtering the TarInfo objects being added to a tar file. When you call add(), you may supply an optional filter argument that’s a callable. The filter callable will be passed the TarInfo for every file being added, and can modify and return it. If the callable returns None, the file will be excluded from the resulting archive. This is more powerful than the existing exclude argument, which has therefore been deprecated. (Added by Lars Gustäbel; bpo-6856 [https://bugs.python.org/issue?@action=redirect&bpo=6856].) The TarFile class also now supports the context management protocol. (Added by Lars Gustäbel; bpo-7232 [https://bugs.python.org/issue?@action=redirect&bpo=7232].)

The wait() method of the threading.Event class now returns the internal flag on exit. This means the method will usually return true because wait() is supposed to block until the internal flag becomes true. The return value will only be false if a timeout was provided and the operation timed out. (Contributed by Tim Lesher; bpo-1674032 [https://bugs.python.org/issue?@action=redirect&bpo=1674032].)

The Unicode database provided by the unicodedata module is now used internally to determine which characters are numeric, whitespace, or represent line breaks. The database also includes information from the Unihan.txt data file (patch by Anders Chrigström and Amaury Forgeot d’Arc; bpo-1571184 [https://bugs.python.org/issue?@action=redirect&bpo=1571184]) and has been updated to version 5.2.0 (updated by Florent Xicluna; bpo-8024 [https://bugs.python.org/issue?@action=redirect&bpo=8024]).

The urlparse module’s urlsplit() now handles unknown URL schemes in a fashion compliant with RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]: if the URL is of the form "<something>://...", the text before the :// is treated as the scheme, even if it’s a made-up scheme that the module doesn’t know about. This change may break code that worked around the old behaviour. For example, Python 2.6.4 or 2.5 will return the following:

>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', '', '//host/filename?query', '', '')

Python 2.7 (and Python 2.6.5) will return:

>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', 'host', '/filename?query', '', '')

(Python 2.7 actually produces slightly different output, since it returns a named tuple instead of a standard tuple.)

The urlparse module also supports IPv6 literal addresses as defined by RFC 2732 [https://datatracker.ietf.org/doc/html/rfc2732.html] (contributed by Senthil Kumaran; bpo-2987 [https://bugs.python.org/issue?@action=redirect&bpo=2987]).

>>> urlparse.urlparse('http://[1080::8:800:200C:417A]/foo')
ParseResult(scheme='http', netloc='[1080::8:800:200C:417A]',
            path='/foo', params='', query='', fragment='')

New class: the WeakSet class in the weakref module is a set that only holds weak references to its elements; elements will be removed once there are no references pointing to them. (Originally implemented in Python 3.x by Raymond Hettinger, and backported to 2.7 by Michael Foord.)

The xml.etree.ElementTree library, no longer escapes ampersands and angle brackets when outputting an XML processing instruction (which looks like <?xml-stylesheet href="#style1"?>) or comment (which looks like <!-- comment -->). (Patch by Neil Muller; bpo-2746 [https://bugs.python.org/issue?@action=redirect&bpo=2746].)

The XML-RPC client and server, provided by the xmlrpclib and SimpleXMLRPCServer modules, have improved performance by supporting HTTP/1.1 keep-alive and by optionally using gzip encoding to compress the XML being exchanged. The gzip compression is controlled by the encode_threshold attribute of SimpleXMLRPCRequestHandler, which contains a size in bytes; responses larger than this will be compressed. (Contributed by Kristján Valur Jónsson; bpo-6267 [https://bugs.python.org/issue?@action=redirect&bpo=6267].)

The zipfile module’s ZipFile now supports the context management protocol, so you can write with zipfile.ZipFile(...) as f:. (Contributed by Brian Curtin; bpo-5511 [https://bugs.python.org/issue?@action=redirect&bpo=5511].)

zipfile now also supports archiving empty directories and extracts them correctly. (Fixed by Kuba Wieczorek; bpo-4710 [https://bugs.python.org/issue?@action=redirect&bpo=4710].) Reading files out of an archive is faster, and interleaving read() and readline() now works correctly. (Contributed by Nir Aides; bpo-7610 [https://bugs.python.org/issue?@action=redirect&bpo=7610].)

The is_zipfile() function now accepts a file object, in addition to the path names accepted in earlier versions. (Contributed by Gabriel Genellina; bpo-4756 [https://bugs.python.org/issue?@action=redirect&bpo=4756].)

The writestr() method now has an optional compress_type parameter that lets you override the default compression method specified in the ZipFile constructor. (Contributed by Ronald Oussoren; bpo-6003 [https://bugs.python.org/issue?@action=redirect&bpo=6003].)

New module: importlib

Python 3.1 includes the importlib package, a re-implementation of the logic underlying Python’s import statement. importlib is useful for implementers of Python interpreters and to users who wish to write new importers that can participate in the import process. Python 2.7 doesn’t contain the complete importlib package, but instead has a tiny subset that contains a single function, import_module().

import_module(name, package=None) imports a module. name is a string containing the module or package’s name. It’s possible to do relative imports by providing a string that begins with a . character, such as ..utils.errors. For relative imports, the package argument must be provided and is the name of the package that will be used as the anchor for the relative import. import_module() both inserts the imported module into sys.modules and returns the module object.

Here are some examples:

>>> from importlib import import_module
>>> anydbm = import_module('anydbm')  # Standard absolute import
>>> anydbm
<module 'anydbm' from '/p/python/Lib/anydbm.py'>
>>> # Relative import
>>> file_util = import_module('..file_util', 'distutils.command')
>>> file_util
<module 'distutils.file_util' from '/python/Lib/distutils/file_util.pyc'>

importlib was implemented by Brett Cannon and introduced in Python 3.1.

New module: sysconfig

The sysconfig module has been pulled out of the Distutils package, becoming a new top-level module in its own right. sysconfig provides functions for getting information about Python’s build process: compiler switches, installation paths, the platform name, and whether Python is running from its source directory.

Some of the functions in the module are:

get_config_var() returns variables from Python’s Makefile and the pyconfig.h file.

get_config_vars() returns a dictionary containing all of the configuration variables.

get_path() returns the configured path for a particular type of module: the standard library, site-specific modules, platform-specific modules, etc.

is_python_build() returns true if you’re running a binary from a Python source tree, and false otherwise.

Consult the sysconfig documentation for more details and for a complete list of functions.

The Distutils package and sysconfig are now maintained by Tarek Ziadé, who has also started a Distutils2 package (source repository at https://hg.python.org/distutils2/) for developing a next-generation version of Distutils.

ttk: Themed Widgets for Tk

Tcl/Tk 8.5 includes a set of themed widgets that re-implement basic Tk widgets but have a more customizable appearance and can therefore more closely resemble the native platform’s widgets. This widget set was originally called Tile, but was renamed to Ttk (for “themed Tk”) on being added to Tcl/Tck release 8.5.

To learn more, read the ttk module documentation. You may also wish to read the Tcl/Tk manual page describing the Ttk theme engine, available at https://www.tcl.tk/man/tcl8.5/TkCmd/ttk_intro.html. Some screenshots of the Python/Ttk code in use are at https://code.google.com/archive/p/python-ttk/wikis/Screenshots.wiki.

The tkinter.ttk module was written by Guilherme Polo and added in bpo-2983 [https://bugs.python.org/issue?@action=redirect&bpo=2983]. An alternate version called Tile.py, written by Martin Franklin and maintained by Kevin Walzer, was proposed for inclusion in bpo-2618 [https://bugs.python.org/issue?@action=redirect&bpo=2618], but the authors argued that Guilherme Polo’s work was more comprehensive.

Updated module: unittest

The unittest module was greatly enhanced; many new features were added. Most of these features were implemented by Michael Foord, unless otherwise noted. The enhanced version of the module is downloadable separately for use with Python versions 2.4 to 2.6, packaged as the unittest2 package, from unittest2 [https://pypi.org/project/unittest2/].

When used from the command line, the module can automatically discover tests. It’s not as fancy as py.test [https://pytest.org] or nose [https://nose.readthedocs.io/], but provides a simple way to run tests kept within a set of package directories. For example, the following command will search the test/ subdirectory for any importable test files named test*.py:

python -m unittest discover -s test

Consult the unittest module documentation for more details. (Developed in bpo-6001 [https://bugs.python.org/issue?@action=redirect&bpo=6001].)

The main() function supports some other new options:

-b or --buffer will buffer the standard output and standard error streams during each test. If the test passes, any resulting output will be discarded; on failure, the buffered output will be displayed.

-c or --catch will cause the control-C interrupt to be handled more gracefully. Instead of interrupting the test process immediately, the currently running test will be completed and then the partial results up to the interruption will be reported. If you’re impatient, a second press of control-C will cause an immediate interruption.

This control-C handler tries to avoid causing problems when the code being tested or the tests being run have defined a signal handler of their own, by noticing that a signal handler was already set and calling it. If this doesn’t work for you, there’s a removeHandler() decorator that can be used to mark tests that should have the control-C handling disabled.

-f or --failfast makes test execution stop immediately when a test fails instead of continuing to execute further tests. (Suggested by Cliff Dyer and implemented by Michael Foord; bpo-8074 [https://bugs.python.org/issue?@action=redirect&bpo=8074].)

The progress messages now show ‘x’ for expected failures and ‘u’ for unexpected successes when run in verbose mode. (Contributed by Benjamin Peterson.)

Test cases can raise the SkipTest exception to skip a test (bpo-1034053 [https://bugs.python.org/issue?@action=redirect&bpo=1034053]).

The error messages for assertEqual(), assertTrue(), and assertFalse() failures now provide more information. If you set the longMessage attribute of your TestCase classes to true, both the standard error message and any additional message you provide will be printed for failures. (Added by Michael Foord; bpo-5663 [https://bugs.python.org/issue?@action=redirect&bpo=5663].)

The assertRaises() method now returns a context handler when called without providing a callable object to run. For example, you can write this:

with self.assertRaises(KeyError):
    {}['foo']

(Implemented by Antoine Pitrou; bpo-4444 [https://bugs.python.org/issue?@action=redirect&bpo=4444].)

Module- and class-level setup and teardown fixtures are now supported. Modules can contain setUpModule() and tearDownModule() functions. Classes can have setUpClass() and tearDownClass() methods that must be defined as class methods (using @classmethod or equivalent). These functions and methods are invoked when the test runner switches to a test case in a different module or class.

The methods addCleanup() and doCleanups() were added. addCleanup() lets you add cleanup functions that will be called unconditionally (after setUp() if setUp() fails, otherwise after tearDown()). This allows for much simpler resource allocation and deallocation during tests (bpo-5679 [https://bugs.python.org/issue?@action=redirect&bpo=5679]).

A number of new methods were added that provide more specialized tests. Many of these methods were written by Google engineers for use in their test suites; Gregory P. Smith, Michael Foord, and GvR worked on merging them into Python’s version of unittest.

assertIsNone() and assertIsNotNone() take one expression and verify that the result is or is not None.

assertIs() and assertIsNot() take two values and check whether the two values evaluate to the same object or not. (Added by Michael Foord; bpo-2578 [https://bugs.python.org/issue?@action=redirect&bpo=2578].)

assertIsInstance() and assertNotIsInstance() check whether the resulting object is an instance of a particular class, or of one of a tuple of classes. (Added by Georg Brandl; bpo-7031 [https://bugs.python.org/issue?@action=redirect&bpo=7031].)

assertGreater(), assertGreaterEqual(), assertLess(), and assertLessEqual() compare two quantities.

assertMultiLineEqual() compares two strings, and if they’re not equal, displays a helpful comparison that highlights the differences in the two strings. This comparison is now used by default when Unicode strings are compared with assertEqual().

assertRegexpMatches() and assertNotRegexpMatches() checks whether the first argument is a string matching or not matching the regular expression provided as the second argument (bpo-8038 [https://bugs.python.org/issue?@action=redirect&bpo=8038]).

assertRaisesRegexp() checks whether a particular exception is raised, and then also checks that the string representation of the exception matches the provided regular expression.

assertIn() and assertNotIn() tests whether first is or is not in second.

assertItemsEqual() tests whether two provided sequences contain the same elements.

assertSetEqual() compares whether two sets are equal, and only reports the differences between the sets in case of error.

Similarly, assertListEqual() and assertTupleEqual() compare the specified types and explain any differences without necessarily printing their full values; these methods are now used by default when comparing lists and tuples using assertEqual(). More generally, assertSequenceEqual() compares two sequences and can optionally check whether both sequences are of a particular type.

assertDictEqual() compares two dictionaries and reports the differences; it’s now used by default when you compare two dictionaries using assertEqual(). assertDictContainsSubset() checks whether all of the key/value pairs in first are found in second.

assertAlmostEqual() and assertNotAlmostEqual() test whether first and second are approximately equal. This method can either round their difference to an optionally specified number of places (the default is 7) and compare it to zero, or require the difference to be smaller than a supplied delta value.

loadTestsFromName() properly honors the suiteClass attribute of the TestLoader. (Fixed by Mark Roddy; bpo-6866 [https://bugs.python.org/issue?@action=redirect&bpo=6866].)

A new hook lets you extend the assertEqual() method to handle new data types. The addTypeEqualityFunc() method takes a type object and a function. The function will be used when both of the objects being compared are of the specified type. This function should compare the two objects and raise an exception if they don’t match; it’s a good idea for the function to provide additional information about why the two objects aren’t matching, much as the new sequence comparison methods do.

unittest.main() now takes an optional exit argument. If false, main() doesn’t call sys.exit(), allowing main() to be used from the interactive interpreter. (Contributed by J. Pablo Fernández; bpo-3379 [https://bugs.python.org/issue?@action=redirect&bpo=3379].)

TestResult has new startTestRun() and stopTestRun() methods that are called immediately before and after a test run. (Contributed by Robert Collins; bpo-5728 [https://bugs.python.org/issue?@action=redirect&bpo=5728].)

With all these changes, the unittest.py was becoming awkwardly large, so the module was turned into a package and the code split into several files (by Benjamin Peterson). This doesn’t affect how the module is imported or used.

더 보기

https://web.archive.org/web/20210619163128/http://www.voidspace.org.uk/python/articles/unittest2.shtml

Describes the new features, how to use them, and the rationale for various design decisions. (By Michael Foord.)

Updated module: ElementTree 1.3

The version of the ElementTree library included with Python was updated to version 1.3. Some of the new features are:

The various parsing functions now take a parser keyword argument giving an XMLParser instance that will be used. This makes it possible to override the file’s internal encoding:

p = ET.XMLParser(encoding='utf-8')
t = ET.XML("""<root/>""", parser=p)

Errors in parsing XML now raise a ParseError exception, whose instances have a position attribute containing a (line, column) tuple giving the location of the problem.

ElementTree’s code for converting trees to a string has been significantly reworked, making it roughly twice as fast in many cases. The ElementTree.write() and Element.write() methods now have a method parameter that can be “xml” (the default), “html”, or “text”. HTML mode will output empty elements as <empty></empty> instead of <empty/>, and text mode will skip over elements and only output the text chunks. If you set the tag attribute of an element to None but leave its children in place, the element will be omitted when the tree is written out, so you don’t need to do more extensive rearrangement to remove a single element.

Namespace handling has also been improved. All xmlns:<whatever> declarations are now output on the root element, not scattered throughout the resulting XML. You can set the default namespace for a tree by setting the default_namespace attribute and can register new prefixes with register_namespace(). In XML mode, you can use the true/false xml_declaration parameter to suppress the XML declaration.

New Element method: extend() appends the items from a sequence to the element’s children. Elements themselves behave like sequences, so it’s easy to move children from one element to another:

from xml.etree import ElementTree as ET

t = ET.XML("""<list>
  <item>1</item> <item>2</item>  <item>3</item>
</list>""")
new = ET.XML('<root/>')
new.extend(t)

# Outputs <root><item>1</item>...</root>
print ET.tostring(new)

New Element method: iter() yields the children of the element as a generator. It’s also possible to write for child in elem: to loop over an element’s children. The existing method getiterator() is now deprecated, as is getchildren() which constructs and returns a list of children.

New Element method: itertext() yields all chunks of text that are descendants of the element. For example:

t = ET.XML("""<list>
  <item>1</item> <item>2</item>  <item>3</item>
</list>""")

# Outputs ['\n  ', '1', ' ', '2', '  ', '3', '\n']
print list(t.itertext())

Deprecated: using an element as a Boolean (i.e., if elem:) would return true if the element had any children, or false if there were no children. This behaviour is confusing – None is false, but so is a childless element? – so it will now trigger a FutureWarning. In your code, you should be explicit: write len(elem) != 0 if you’re interested in the number of children, or elem is not None.

Fredrik Lundh develops ElementTree and produced the 1.3 version; you can read his article describing 1.3 at https://web.archive.org/web/20200703234532/http://effbot.org/zone/elementtree-13-intro.htm. Florent Xicluna updated the version included with Python, after discussions on python-dev and in bpo-6472 [https://bugs.python.org/issue?@action=redirect&bpo=6472].)

Build and C API Changes

Changes to Python’s build process and to the C API include:

The latest release of the GNU Debugger, GDB 7, can be scripted using Python [https://web.archive.org/web/20110715084810/http://sourceware.org/gdb/current/onlinedocs/gdb/Python.html]. When you begin debugging an executable program P, GDB will look for a file named P-gdb.py and automatically read it. Dave Malcolm contributed a python-gdb.py that adds a number of commands useful when debugging Python itself. For example, py-up and py-down go up or down one Python stack frame, which usually corresponds to several C stack frames. py-print prints the value of a Python variable, and py-bt prints the Python stack trace. (Added as a result of bpo-8032 [https://bugs.python.org/issue?@action=redirect&bpo=8032].)

If you use the .gdbinit file provided with Python, the “pyo” macro in the 2.7 version now works correctly when the thread being debugged doesn’t hold the GIL; the macro now acquires it before printing. (Contributed by Victor Stinner; bpo-3632 [https://bugs.python.org/issue?@action=redirect&bpo=3632].)

Py_AddPendingCall() is now thread-safe, letting any worker thread submit notifications to the main Python thread. This is particularly useful for asynchronous IO operations. (Contributed by Kristján Valur Jónsson; bpo-4293 [https://bugs.python.org/issue?@action=redirect&bpo=4293].)

New function: PyCode_NewEmpty() creates an empty code object; only the filename, function name, and first line number are required. This is useful for extension modules that are attempting to construct a more useful traceback stack. Previously such extensions needed to call PyCode_New(), which had many more arguments. (Added by Jeffrey Yasskin.)

New function: PyErr_NewExceptionWithDoc() creates a new exception class, just as the existing PyErr_NewException() does, but takes an extra char * argument containing the docstring for the new exception class. (Added by ‘lekma’ on the Python bug tracker; bpo-7033 [https://bugs.python.org/issue?@action=redirect&bpo=7033].)

New function: PyFrame_GetLineNumber() takes a frame object and returns the line number that the frame is currently executing. Previously code would need to get the index of the bytecode instruction currently executing, and then look up the line number corresponding to that address. (Added by Jeffrey Yasskin.)

New functions: PyLong_AsLongAndOverflow() and PyLong_AsLongLongAndOverflow() approximates a Python long integer as a C long or long long. If the number is too large to fit into the output type, an overflow flag is set and returned to the caller. (Contributed by Case Van Horsen; bpo-7528 [https://bugs.python.org/issue?@action=redirect&bpo=7528] and bpo-7767 [https://bugs.python.org/issue?@action=redirect&bpo=7767].)

New function: stemming from the rewrite of string-to-float conversion, a new PyOS_string_to_double() function was added. The old PyOS_ascii_strtod() and PyOS_ascii_atof() functions are now deprecated.

New function: PySys_SetArgvEx() sets the value of sys.argv and can optionally update sys.path to include the directory containing the script named by sys.argv[0] depending on the value of an updatepath parameter.

This function was added to close a security hole for applications that embed Python. The old function, PySys_SetArgv(), would always update sys.path, and sometimes it would add the current directory. This meant that, if you ran an application embedding Python in a directory controlled by someone else, attackers could put a Trojan-horse module in the directory (say, a file named os.py) that your application would then import and run.

If you maintain a C/C++ application that embeds Python, check whether you’re calling PySys_SetArgv() and carefully consider whether the application should be using PySys_SetArgvEx() with updatepath set to false.

Security issue reported as CVE 2008-5983 [https://www.cve.org/CVERecord?id=CVE-2008-5983]; discussed in bpo-5753 [https://bugs.python.org/issue?@action=redirect&bpo=5753], and fixed by Antoine Pitrou.

New macros: the Python header files now define the following macros: Py_ISALNUM, Py_ISALPHA, Py_ISDIGIT, Py_ISLOWER, Py_ISSPACE, Py_ISUPPER, Py_ISXDIGIT, Py_TOLOWER, and Py_TOUPPER. All of these functions are analogous to the C standard macros for classifying characters, but ignore the current locale setting, because in several places Python needs to analyze characters in a locale-independent way. (Added by Eric Smith; bpo-5793 [https://bugs.python.org/issue?@action=redirect&bpo=5793].)

Removed function: PyEval_CallObject() is now only available as a macro. A function version was being kept around to preserve ABI linking compatibility, but that was in 1997; it can certainly be deleted by now. (Removed by Antoine Pitrou; bpo-8276 [https://bugs.python.org/issue?@action=redirect&bpo=8276].)

New format codes: the PyString_FromFormat(), PyString_FromFormatV(), and PyErr_Format() functions now accept %lld and %llu format codes for displaying C’s long long types. (Contributed by Mark Dickinson; bpo-7228 [https://bugs.python.org/issue?@action=redirect&bpo=7228].)

The complicated interaction between threads and process forking has been changed. Previously, the child process created by os.fork() might fail because the child is created with only a single thread running, the thread performing the os.fork(). If other threads were holding a lock, such as Python’s import lock, when the fork was performed, the lock would still be marked as “held” in the new process. But in the child process nothing would ever release the lock, since the other threads weren’t replicated, and the child process would no longer be able to perform imports.

Python 2.7 acquires the import lock before performing an os.fork(), and will also clean up any locks created using the threading module. C extension modules that have internal locks, or that call fork() themselves, will not benefit from this clean-up.

(Fixed by Thomas Wouters; bpo-1590864 [https://bugs.python.org/issue?@action=redirect&bpo=1590864].)

The Py_Finalize() function now calls the internal threading._shutdown() function; this prevents some exceptions from being raised when an interpreter shuts down. (Patch by Adam Olsen; bpo-1722344 [https://bugs.python.org/issue?@action=redirect&bpo=1722344].)

When using the PyMemberDef structure to define attributes of a type, Python will no longer let you try to delete or set a T_STRING_INPLACE attribute.

Global symbols defined by the ctypes module are now prefixed with Py, or with _ctypes. (Implemented by Thomas Heller; bpo-3102 [https://bugs.python.org/issue?@action=redirect&bpo=3102].)

New configure option: the --with-system-expat switch allows building the pyexpat module to use the system Expat library. (Contributed by Arfrever Frehtes Taifersar Arahesis; bpo-7609 [https://bugs.python.org/issue?@action=redirect&bpo=7609].)

New configure option: the --with-valgrind option will now disable the pymalloc allocator, which is difficult for the Valgrind memory-error detector to analyze correctly. Valgrind will therefore be better at detecting memory leaks and overruns. (Contributed by James Henstridge; bpo-2422 [https://bugs.python.org/issue?@action=redirect&bpo=2422].)

New configure option: you can now supply an empty string to --with-dbmliborder= in order to disable all of the various DBM modules. (Added by Arfrever Frehtes Taifersar Arahesis; bpo-6491 [https://bugs.python.org/issue?@action=redirect&bpo=6491].)

The configure script now checks for floating-point rounding bugs on certain 32-bit Intel chips and defines a X87_DOUBLE_ROUNDING preprocessor definition. No code currently uses this definition, but it’s available if anyone wishes to use it. (Added by Mark Dickinson; bpo-2937 [https://bugs.python.org/issue?@action=redirect&bpo=2937].)

configure also now sets a LDCXXSHARED Makefile variable for supporting C++ linking. (Contributed by Arfrever Frehtes Taifersar Arahesis; bpo-1222585 [https://bugs.python.org/issue?@action=redirect&bpo=1222585].)

The build process now creates the necessary files for pkg-config support. (Contributed by Clinton Roy; bpo-3585 [https://bugs.python.org/issue?@action=redirect&bpo=3585].)

The build process now supports Subversion 1.7. (Contributed by Arfrever Frehtes Taifersar Arahesis; bpo-6094 [https://bugs.python.org/issue?@action=redirect&bpo=6094].)

Capsules

Python 3.1 adds a new C datatype, PyCapsule, for providing a C API to an extension module. A capsule is essentially the holder of a C void * pointer, and is made available as a module attribute; for example, the socket module’s API is exposed as socket.CAPI, and unicodedata exposes ucnhash_CAPI. Other extensions can import the module, access its dictionary to get the capsule object, and then get the void * pointer, which will usually point to an array of pointers to the module’s various API functions.

There is an existing data type already used for this, PyCObject, but it doesn’t provide type safety. Evil code written in pure Python could cause a segmentation fault by taking a PyCObject from module A and somehow substituting it for the PyCObject in module B. Capsules know their own name, and getting the pointer requires providing the name:

void *vtable;

if (!PyCapsule_IsValid(capsule, "mymodule.CAPI") {
        PyErr_SetString(PyExc_ValueError, "argument type invalid");
        return NULL;
}

vtable = PyCapsule_GetPointer(capsule, "mymodule.CAPI");

You are assured that vtable points to whatever you’re expecting. If a different capsule was passed in, PyCapsule_IsValid() would detect the mismatched name and return false. Refer to 확장 모듈을 위한 C API 제공하기 for more information on using these objects.

Python 2.7 now uses capsules internally to provide various extension-module APIs, but the PyCObject_AsVoidPtr() was modified to handle capsules, preserving compile-time compatibility with the PyCObject interface. Use of PyCObject_AsVoidPtr() will signal a PendingDeprecationWarning, which is silent by default.

Implemented in Python 3.1 and backported to 2.7 by Larry Hastings; discussed in bpo-5630 [https://bugs.python.org/issue?@action=redirect&bpo=5630].

Port-Specific Changes: Windows

The msvcrt module now contains some constants from the crtassem.h header file: CRT_ASSEMBLY_VERSION, VC_ASSEMBLY_PUBLICKEYTOKEN, and LIBRARIES_ASSEMBLY_NAME_PREFIX. (Contributed by David Cournapeau; bpo-4365 [https://bugs.python.org/issue?@action=redirect&bpo=4365].)

The _winreg module for accessing the registry now implements the CreateKeyEx() and DeleteKeyEx() functions, extended versions of previously supported functions that take several extra arguments. The DisableReflectionKey(), EnableReflectionKey(), and QueryReflectionKey() were also tested and documented. (Implemented by Brian Curtin: bpo-7347 [https://bugs.python.org/issue?@action=redirect&bpo=7347].)

The new _beginthreadex() API is used to start threads, and the native thread-local storage functions are now used. (Contributed by Kristján Valur Jónsson; bpo-3582 [https://bugs.python.org/issue?@action=redirect&bpo=3582].)

The os.kill() function now works on Windows. The signal value can be the constants CTRL_C_EVENT, CTRL_BREAK_EVENT, or any integer. The first two constants will send Control-C and Control-Break keystroke events to subprocesses; any other value will use the TerminateProcess() API. (Contributed by Miki Tebeka; bpo-1220212 [https://bugs.python.org/issue?@action=redirect&bpo=1220212].)

The os.listdir() function now correctly fails for an empty path. (Fixed by Hirokazu Yamamoto; bpo-5913 [https://bugs.python.org/issue?@action=redirect&bpo=5913].)

The mimetypes module will now read the MIME database from the Windows registry when initializing. (Patch by Gabriel Genellina; bpo-4969 [https://bugs.python.org/issue?@action=redirect&bpo=4969].)

Port-Specific Changes: Mac OS X

The path /Library/Python/2.7/site-packages is now appended to sys.path, in order to share added packages between the system installation and a user-installed copy of the same version. (Changed by Ronald Oussoren; bpo-4865 [https://bugs.python.org/issue?@action=redirect&bpo=4865].)

버전 2.7.13에서 변경: As of 2.7.13, this change was removed. /Library/Python/2.7/site-packages, the site-packages directory used by the Apple-supplied system Python 2.7 is no longer appended to sys.path for user-installed Pythons such as from the python.org installers. As of macOS 10.12, Apple changed how the system site-packages directory is configured, which could cause installation of pip components, like setuptools, to fail. Packages installed for the system Python will no longer be shared with user-installed Pythons. (bpo-28440 [https://bugs.python.org/issue?@action=redirect&bpo=28440])

Port-Specific Changes: FreeBSD

FreeBSD 7.1’s SO_SETFIB constant, used with the socket() methods getsockopt()/setsockopt() to select an alternate routing table, is now available in the socket module. (Added by Kyle VanderBeek; bpo-8235 [https://bugs.python.org/issue?@action=redirect&bpo=8235].)

Other Changes and Fixes

Two benchmark scripts, iobench and ccbench, were added to the Tools directory. iobench measures the speed of the built-in file I/O objects returned by open() while performing various operations, and ccbench is a concurrency benchmark that tries to measure computing throughput, thread switching latency, and IO processing bandwidth when performing several tasks using a varying number of threads.

The Tools/i18n/msgfmt.py script now understands plural forms in .po files. (Fixed by Martin von Löwis; bpo-5464 [https://bugs.python.org/issue?@action=redirect&bpo=5464].)

When importing a module from a .pyc or .pyo file with an existing .py counterpart, the co_filename attributes of the resulting code objects are overwritten when the original filename is obsolete. This can happen if the file has been renamed, moved, or is accessed through different paths. (Patch by Ziga Seilnacht and Jean-Paul Calderone; bpo-1180193 [https://bugs.python.org/issue?@action=redirect&bpo=1180193].)

The regrtest.py script now takes a --randseed= switch that takes an integer that will be used as the random seed for the -r option that executes tests in random order. The -r option also reports the seed that was used (Added by Collin Winter.)

Another regrtest.py switch is -j, which takes an integer specifying how many tests run in parallel. This allows reducing the total runtime on multi-core machines. This option is compatible with several other options, including the -R switch which is known to produce long runtimes. (Added by Antoine Pitrou, bpo-6152 [https://bugs.python.org/issue?@action=redirect&bpo=6152].) This can also be used with a new -F switch that runs selected tests in a loop until they fail. (Added by Antoine Pitrou; bpo-7312 [https://bugs.python.org/issue?@action=redirect&bpo=7312].)

When executed as a script, the py_compile.py module now accepts '-' as an argument, which will read standard input for the list of filenames to be compiled. (Contributed by Piotr Ożarowski; bpo-8233 [https://bugs.python.org/issue?@action=redirect&bpo=8233].)

Porting to Python 2.7

This section lists previously described changes and other bugfixes that may require changes to your code:

The range() function processes its arguments more consistently; it will now call __int__() on non-float, non-integer arguments that are supplied to it. (Fixed by Alexander Belopolsky; bpo-1533 [https://bugs.python.org/issue?@action=redirect&bpo=1533].)

The string format() method changed the default precision used for floating-point and complex numbers from 6 decimal places to 12, which matches the precision used by str(). (Changed by Eric Smith; bpo-5920 [https://bugs.python.org/issue?@action=redirect&bpo=5920].)

Because of an optimization for the with statement, the special methods __enter__() and __exit__() must belong to the object’s type, and cannot be directly attached to the object’s instance. This affects new-style classes (derived from object) and C extension types. (bpo-6101 [https://bugs.python.org/issue?@action=redirect&bpo=6101].)

Due to a bug in Python 2.6, the exc_value parameter to __exit__() methods was often the string representation of the exception, not an instance. This was fixed in 2.7, so exc_value will be an instance as expected. (Fixed by Florent Xicluna; bpo-7853 [https://bugs.python.org/issue?@action=redirect&bpo=7853].)

When a restricted set of attributes were set using __slots__, deleting an unset attribute would not raise AttributeError as you would expect. Fixed by Benjamin Peterson; bpo-7604 [https://bugs.python.org/issue?@action=redirect&bpo=7604].)

In the standard library:

Operations with datetime instances that resulted in a year falling outside the supported range didn’t always raise OverflowError. Such errors are now checked more carefully and will now raise the exception. (Reported by Mark Leander, patch by Anand B. Pillai and Alexander Belopolsky; bpo-7150 [https://bugs.python.org/issue?@action=redirect&bpo=7150].)

When using Decimal instances with a string’s format() method, the default alignment was previously left-alignment. This has been changed to right-alignment, which might change the output of your programs. (Changed by Mark Dickinson; bpo-6857 [https://bugs.python.org/issue?@action=redirect&bpo=6857].)

Comparisons involving a signaling NaN value (or sNAN) now signal InvalidOperation instead of silently returning a true or false value depending on the comparison operator. Quiet NaN values (or NaN) are now hashable. (Fixed by Mark Dickinson; bpo-7279 [https://bugs.python.org/issue?@action=redirect&bpo=7279].)

The xml.etree.ElementTree library no longer escapes ampersands and angle brackets when outputting an XML processing instruction (which looks like <?xml-stylesheet href="#style1"?>) or comment (which looks like <!-- comment -->). (Patch by Neil Muller; bpo-2746 [https://bugs.python.org/issue?@action=redirect&bpo=2746].)

The readline() method of StringIO objects now does nothing when a negative length is requested, as other file-like objects do. (bpo-7348 [https://bugs.python.org/issue?@action=redirect&bpo=7348]).

The syslog module will now use the value of sys.argv[0] as the identifier instead of the previous default value of 'python'. (Changed by Sean Reifschneider; bpo-8451 [https://bugs.python.org/issue?@action=redirect&bpo=8451].)

The tarfile module’s default error handling has changed, to no longer suppress fatal errors. The default error level was previously 0, which meant that errors would only result in a message being written to the debug log, but because the debug log is not activated by default, these errors go unnoticed. The default error level is now 1, which raises an exception if there’s an error. (Changed by Lars Gustäbel; bpo-7357 [https://bugs.python.org/issue?@action=redirect&bpo=7357].)

The urlparse module’s urlsplit() now handles unknown URL schemes in a fashion compliant with RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]: if the URL is of the form "<something>://...", the text before the :// is treated as the scheme, even if it’s a made-up scheme that the module doesn’t know about. This change may break code that worked around the old behaviour. For example, Python 2.6.4 or 2.5 will return the following:

>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', '', '//host/filename?query', '', '')

Python 2.7 (and Python 2.6.5) will return:

>>> import urlparse
>>> urlparse.urlsplit('invented://host/filename?query')
('invented', 'host', '/filename?query', '', '')

(Python 2.7 actually produces slightly different output, since it returns a named tuple instead of a standard tuple.)

For C extensions:

C extensions that use integer format codes with the PyArg_Parse* family of functions will now raise a TypeError exception instead of triggering a DeprecationWarning (bpo-5080 [https://bugs.python.org/issue?@action=redirect&bpo=5080]).

Use the new PyOS_string_to_double() function instead of the old PyOS_ascii_strtod() and PyOS_ascii_atof() functions, which are now deprecated.

For applications that embed Python:

The PySys_SetArgvEx() function was added, letting applications close a security hole when the existing PySys_SetArgv() function was used. Check whether you’re calling PySys_SetArgv() and carefully consider whether the application should be using PySys_SetArgvEx() with updatepath set to false.

New Features Added to Python 2.7 Maintenance Releases

New features may be added to Python 2.7 maintenance releases when the situation genuinely calls for it. Any such additions must go through the Python Enhancement Proposal process, and make a compelling case for why they can’t be adequately addressed by either adding the new feature solely to Python 3, or else by publishing it on the Python Package Index.

In addition to the specific proposals listed below, there is a general exemption allowing new -3 warnings to be added in any Python 2.7 maintenance release.

Two new environment variables for debug mode

In debug mode, the [xxx refs] statistic is not written by default, the PYTHONSHOWREFCOUNT environment variable now must also be set. (Contributed by Victor Stinner; bpo-31733 [https://bugs.python.org/issue?@action=redirect&bpo=31733].)

When Python is compiled with COUNT_ALLOC defined, allocation counts are no longer dumped by default anymore: the PYTHONSHOWALLOCCOUNT environment variable must now also be set. Moreover, allocation counts are now dumped into stderr, rather than stdout. (Contributed by Victor Stinner; bpo-31692 [https://bugs.python.org/issue?@action=redirect&bpo=31692].)

Added in version 2.7.15.

PEP 434: IDLE Enhancement Exception for All Branches

PEP 434 [https://peps.python.org/pep-0434/] describes a general exemption for changes made to the IDLE development environment shipped along with Python. This exemption makes it possible for the IDLE developers to provide a more consistent user experience across all supported versions of Python 2 and 3.

For details of any IDLE changes, refer to the NEWS file for the specific release.

PEP 466: Network Security Enhancements for Python 2.7

PEP 466 [https://peps.python.org/pep-0466/] describes a number of network security enhancement proposals that have been approved for inclusion in Python 2.7 maintenance releases, with the first of those changes appearing in the Python 2.7.7 release.

PEP 466 [https://peps.python.org/pep-0466/] related features added in Python 2.7.7:

hmac.compare_digest() was backported from Python 3 to make a timing attack resistant comparison operation available to Python 2 applications. (Contributed by Alex Gaynor; bpo-21306 [https://bugs.python.org/issue?@action=redirect&bpo=21306].)

OpenSSL 1.0.1g was upgraded in the official Windows installers published on python.org. (Contributed by Zachary Ware; bpo-21462 [https://bugs.python.org/issue?@action=redirect&bpo=21462].)

PEP 466 [https://peps.python.org/pep-0466/] related features added in Python 2.7.8:

hashlib.pbkdf2_hmac() was backported from Python 3 to make a hashing algorithm suitable for secure password storage broadly available to Python 2 applications. (Contributed by Alex Gaynor; bpo-21304 [https://bugs.python.org/issue?@action=redirect&bpo=21304].)

OpenSSL 1.0.1h was upgraded for the official Windows installers published on python.org. (Contributed by Zachary Ware in bpo-21671 [https://bugs.python.org/issue?@action=redirect&bpo=21671] for CVE 2014-0224 [https://www.cve.org/CVERecord?id=CVE-2014-0224].)

PEP 466 [https://peps.python.org/pep-0466/] related features added in Python 2.7.9:

Most of Python 3.4’s ssl module was backported. This means ssl now supports Server Name Indication, TLS1.x settings, access to the platform certificate store, the SSLContext class, and other features. (Contributed by Alex Gaynor and David Reid; bpo-21308 [https://bugs.python.org/issue?@action=redirect&bpo=21308].)

Refer to the “Version added: 2.7.9” notes in the module documentation for specific details.

os.urandom() was changed to cache a file descriptor to /dev/urandom instead of reopening /dev/urandom on every call. (Contributed by Alex Gaynor; bpo-21305 [https://bugs.python.org/issue?@action=redirect&bpo=21305].)

hashlib.algorithms_guaranteed and hashlib.algorithms_available were backported from Python 3 to make it easier for Python 2 applications to select the strongest available hash algorithm. (Contributed by Alex Gaynor in bpo-21307 [https://bugs.python.org/issue?@action=redirect&bpo=21307])

PEP 477: Backport ensurepip (PEP 453) to Python 2.7

PEP 477 [https://peps.python.org/pep-0477/] approves the inclusion of the PEP 453 [https://peps.python.org/pep-0453/] ensurepip module and the improved documentation that was enabled by it in the Python 2.7 maintenance releases, appearing first in the Python 2.7.9 release.

Bootstrapping pip By Default

The new ensurepip module (defined in PEP 453 [https://peps.python.org/pep-0453/]) provides a standard cross-platform mechanism to bootstrap the pip installer into Python installations. The version of pip included with Python 2.7.9 is pip 1.5.6, and future 2.7.x maintenance releases will update the bundled version to the latest version of pip that is available at the time of creating the release candidate.

By default, the commands pip, pipX and pipX.Y will be installed on all platforms (where X.Y stands for the version of the Python installation), along with the pip Python package and its dependencies.

For CPython source builds on POSIX systems, the make install and make altinstall commands do not bootstrap pip by default. This behaviour can be controlled through configure options, and overridden through Makefile options.

On Windows and Mac OS X, the CPython installers now default to installing pip along with CPython itself (users may opt out of installing it during the installation process). Window users will need to opt in to the automatic PATH modifications to have pip available from the command line by default, otherwise it can still be accessed through the Python launcher for Windows as py -m pip.

As discussed in the PEP [https://peps.python.org/pep-0477/#disabling-ensurepip-by-downstream-distributors], platform packagers may choose not to install these commands by default, as long as, when invoked, they provide clear and simple directions on how to install them on that platform (usually using the system package manager).

Documentation Changes

As part of this change, the 파이썬 모듈 설치하기 and 파이썬 모듈 배포하기 sections of the documentation have been completely redesigned as short getting started and FAQ documents. Most packaging documentation has now been moved out to the Python Packaging Authority maintained Python Packaging User Guide [https://packaging.python.org] and the documentation of the individual projects.

However, as this migration is currently still incomplete, the legacy versions of those guides remaining available as Building C and C++ Extensions with setuptools and Building C and C++ Extensions with setuptools.

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PEP 453 [https://peps.python.org/pep-0453/] – Explicit bootstrapping of pip in Python installations

PEP written by Donald Stufft and Nick Coghlan, implemented by Donald Stufft, Nick Coghlan, Martin von Löwis and Ned Deily.

PEP 476: Enabling certificate verification by default for stdlib http clients

PEP 476 [https://peps.python.org/pep-0476/] updated httplib and modules which use it, such as urllib2 and xmlrpclib, to now verify that the server presents a certificate which is signed by a Certificate Authority in the platform trust store and whose hostname matches the hostname being requested by default, significantly improving security for many applications. This change was made in the Python 2.7.9 release.

For applications which require the old previous behavior, they can pass an alternate context:

import urllib2
import ssl

# This disables all verification
context = ssl._create_unverified_context()

# This allows using a specific certificate for the host, which doesn't need
# to be in the trust store
context = ssl.create_default_context(cafile="/path/to/file.crt")

urllib2.urlopen("https://invalid-cert", context=context)

PEP 493: HTTPS verification migration tools for Python 2.7

PEP 493 [https://peps.python.org/pep-0493/] provides additional migration tools to support a more incremental infrastructure upgrade process for environments containing applications and services relying on the historically permissive processing of server certificates when establishing client HTTPS connections. These additions were made in the Python 2.7.12 release.

These tools are intended for use in cases where affected applications and services can’t be modified to explicitly pass a more permissive SSL context when establishing the connection.

For applications and services which can’t be modified at all, the new PYTHONHTTPSVERIFY environment variable may be set to 0 to revert an entire Python process back to the default permissive behaviour of Python 2.7.8 and earlier.

For cases where the connection establishment code can’t be modified, but the overall application can be, the new ssl._https_verify_certificates() function can be used to adjust the default behaviour at runtime.

New make regen-all build target

To simplify cross-compilation, and to ensure that CPython can reliably be compiled without requiring an existing version of Python to already be available, the autotools-based build system no longer attempts to implicitly recompile generated files based on file modification times.

Instead, a new make regen-all command has been added to force regeneration of these files when desired (e.g. after an initial version of Python has already been built based on the pregenerated versions).

More selective regeneration targets are also defined - see Makefile.pre.in [https://github.com/python/cpython/tree/main/Makefile.pre.in] for details.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

Added in version 2.7.14.

Removal of make touch build target

The make touch build target previously used to request implicit regeneration of generated files by updating their modification times has been removed.

It has been replaced by the new make regen-all target.

(Contributed by Victor Stinner in bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404].)

버전 2.7.14에서 변경.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Nick Coghlan, Philip Jenvey, Ryan Lovett, R. David Murray, Hugh Secker-Walker.

What’s New in Python 2.6

Author:

A.M. Kuchling (amk at amk.ca)

This article explains the new features in Python 2.6, released on October 1, 2008. The release schedule is described in PEP 361 [https://peps.python.org/pep-0361/].

The major theme of Python 2.6 is preparing the migration path to Python 3.0, a major redesign of the language. Whenever possible, Python 2.6 incorporates new features and syntax from 3.0 while remaining compatible with existing code by not removing older features or syntax. When it’s not possible to do that, Python 2.6 tries to do what it can, adding compatibility functions in a future_builtins module and a -3 switch to warn about usages that will become unsupported in 3.0.

Some significant new packages have been added to the standard library, such as the multiprocessing and json modules, but there aren’t many new features that aren’t related to Python 3.0 in some way.

Python 2.6 also sees a number of improvements and bugfixes throughout the source. A search through the change logs finds there were 259 patches applied and 612 bugs fixed between Python 2.5 and 2.6. Both figures are likely to be underestimates.

This article doesn’t attempt to provide a complete specification of the new features, but instead provides a convenient overview. For full details, you should refer to the documentation for Python 2.6. If you want to understand the rationale for the design and implementation, refer to the PEP for a particular new feature. Whenever possible, “What’s New in Python” links to the bug/patch item for each change.

Python 3.0

The development cycle for Python versions 2.6 and 3.0 was synchronized, with the alpha and beta releases for both versions being made on the same days. The development of 3.0 has influenced many features in 2.6.

Python 3.0 is a far-ranging redesign of Python that breaks compatibility with the 2.x series. This means that existing Python code will need some conversion in order to run on Python 3.0. However, not all the changes in 3.0 necessarily break compatibility. In cases where new features won’t cause existing code to break, they’ve been backported to 2.6 and are described in this document in the appropriate place. Some of the 3.0-derived features are:

A __complex__() method for converting objects to a complex number.

Alternate syntax for catching exceptions: except TypeError as exc.

The addition of functools.reduce() as a synonym for the built-in reduce() function.

Python 3.0 adds several new built-in functions and changes the semantics of some existing builtins. Functions that are new in 3.0 such as bin() have simply been added to Python 2.6, but existing builtins haven’t been changed; instead, the future_builtins module has versions with the new 3.0 semantics. Code written to be compatible with 3.0 can do from future_builtins import hex, map as necessary.

A new command-line switch, -3, enables warnings about features that will be removed in Python 3.0. You can run code with this switch to see how much work will be necessary to port code to 3.0. The value of this switch is available to Python code as the boolean variable sys.py3kwarning, and to C extension code as Py_Py3kWarningFlag.

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The 3xxx series of PEPs, which contains proposals for Python 3.0. PEP 3000 [https://peps.python.org/pep-3000/] describes the development process for Python 3.0. Start with PEP 3100 [https://peps.python.org/pep-3100/] that describes the general goals for Python 3.0, and then explore the higher-numbered PEPs that propose specific features.

Changes to the Development Process

While 2.6 was being developed, the Python development process underwent two significant changes: we switched from SourceForge’s issue tracker to a customized Roundup installation, and the documentation was converted from LaTeX to reStructuredText.

New Issue Tracker: Roundup

For a long time, the Python developers had been growing increasingly annoyed by SourceForge’s bug tracker. SourceForge’s hosted solution doesn’t permit much customization; for example, it wasn’t possible to customize the life cycle of issues.

The infrastructure committee of the Python Software Foundation therefore posted a call for issue trackers, asking volunteers to set up different products and import some of the bugs and patches from SourceForge. Four different trackers were examined: Jira [https://www.atlassian.com/software/jira/], Launchpad [https://launchpad.net/], Roundup [https://roundup.sourceforge.io/], and Trac [https://trac.edgewall.org/]. The committee eventually settled on Jira and Roundup as the two candidates. Jira is a commercial product that offers no-cost hosted instances to free-software projects; Roundup is an open-source project that requires volunteers to administer it and a server to host it.

After posting a call for volunteers, a new Roundup installation was set up at https://bugs.python.org. One installation of Roundup can host multiple trackers, and this server now also hosts issue trackers for Jython and for the Python web site. It will surely find other uses in the future. Where possible, this edition of “What’s New in Python” links to the bug/patch item for each change.

Hosting of the Python bug tracker is kindly provided by Upfront Systems [https://upfrontsoftware.co.za] of Stellenbosch, South Africa. Martin von Löwis put a lot of effort into importing existing bugs and patches from SourceForge; his scripts for this import operation are at https://svn.python.org/view/tracker/importer/ and may be useful to other projects wishing to move from SourceForge to Roundup.

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https://bugs.python.org

The Python bug tracker.

https://bugs.jython.org:

The Jython bug tracker.

https://roundup.sourceforge.io/

Roundup downloads and documentation.

https://svn.python.org/view/tracker/importer/

Martin von Löwis’s conversion scripts.

New Documentation Format: reStructuredText Using Sphinx

The Python documentation was written using LaTeX since the project started around 1989. In the 1980s and early 1990s, most documentation was printed out for later study, not viewed online. LaTeX was widely used because it provided attractive printed output while remaining straightforward to write once the basic rules of the markup were learned.

Today LaTeX is still used for writing publications destined for printing, but the landscape for programming tools has shifted. We no longer print out reams of documentation; instead, we browse through it online and HTML has become the most important format to support. Unfortunately, converting LaTeX to HTML is fairly complicated and Fred L. Drake Jr., the long-time Python documentation editor, spent a lot of time maintaining the conversion process. Occasionally people would suggest converting the documentation into SGML and later XML, but performing a good conversion is a major task and no one ever committed the time required to finish the job.

During the 2.6 development cycle, Georg Brandl put a lot of effort into building a new toolchain for processing the documentation. The resulting package is called Sphinx, and is available from https://www.sphinx-doc.org/.

Sphinx concentrates on HTML output, producing attractively styled and modern HTML; printed output is still supported through conversion to LaTeX. The input format is reStructuredText, a markup syntax supporting custom extensions and directives that is commonly used in the Python community.

Sphinx is a standalone package that can be used for writing, and almost two dozen other projects (listed on the Sphinx web site [https://www.sphinx-doc.org/en/master/examples.html]) have adopted Sphinx as their documentation tool.

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Documenting Python [https://devguide.python.org/documenting/]

Describes how to write for Python’s documentation.

Sphinx [https://www.sphinx-doc.org/]

Documentation and code for the Sphinx toolchain.

Docutils [https://docutils.sourceforge.io]

The underlying reStructuredText parser and toolset.

PEP 343: The ‘with’ statement

The previous version, Python 2.5, added the ‘with’ statement as an optional feature, to be enabled by a from __future__ import with_statement directive. In 2.6 the statement no longer needs to be specially enabled; this means that with is now always a keyword. The rest of this section is a copy of the corresponding section from the “What’s New in Python 2.5” document; if you’re familiar with the ‘with’ statement from Python 2.5, you can skip this section.

The ‘with’ statement clarifies code that previously would use try...finally blocks to ensure that clean-up code is executed. In this section, I’ll discuss the statement as it will commonly be used. In the next section, I’ll examine the implementation details and show how to write objects for use with this statement.

The ‘with’ statement is a control-flow structure whose basic structure is:

with expression [as variable]:
    with-block

The expression is evaluated, and it should result in an object that supports the context management protocol (that is, has __enter__() and __exit__() methods).

The object’s __enter__() is called before with-block is executed and therefore can run set-up code. It also may return a value that is bound to the name variable, if given. (Note carefully that variable is not assigned the result of expression.)

After execution of the with-block is finished, the object’s __exit__() method is called, even if the block raised an exception, and can therefore run clean-up code.

Some standard Python objects now support the context management protocol and can be used with the ‘with’ statement. File objects are one example:

with open('/etc/passwd', 'r') as f:
    for line in f:
        print line
        ... more processing code ...

After this statement has executed, the file object in f will have been automatically closed, even if the for loop raised an exception part-way through the block.

참고

In this case, f is the same object created by open(), because __enter__() returns self.

The threading module’s locks and condition variables also support the ‘with’ statement:

lock = threading.Lock()
with lock:
    # Critical section of code
    ...

The lock is acquired before the block is executed and always released once the block is complete.

The localcontext() function in the decimal module makes it easy to save and restore the current decimal context, which encapsulates the desired precision and rounding characteristics for computations:

from decimal import Decimal, Context, localcontext

# Displays with default precision of 28 digits
v = Decimal('578')
print v.sqrt()

with localcontext(Context(prec=16)):
    # All code in this block uses a precision of 16 digits.
    # The original context is restored on exiting the block.
    print v.sqrt()

Writing Context Managers

Under the hood, the ‘with’ statement is fairly complicated. Most people will only use ‘with’ in company with existing objects and don’t need to know these details, so you can skip the rest of this section if you like. Authors of new objects will need to understand the details of the underlying implementation and should keep reading.

A high-level explanation of the context management protocol is:

The expression is evaluated and should result in an object called a “context manager”. The context manager must have __enter__() and __exit__() methods.

The context manager’s __enter__() method is called. The value returned is assigned to VAR. If no as VAR clause is present, the value is simply discarded.

The code in BLOCK is executed.

If BLOCK raises an exception, the context manager’s __exit__() method is called with three arguments, the exception details (type, value, traceback, the same values returned by sys.exc_info(), which can also be None if no exception occurred). The method’s return value controls whether an exception is re-raised: any false value re-raises the exception, and True will result in suppressing it. You’ll only rarely want to suppress the exception, because if you do the author of the code containing the ‘with’ statement will never realize anything went wrong.

If BLOCK didn’t raise an exception, the __exit__() method is still called, but type, value, and traceback are all None.

Let’s think through an example. I won’t present detailed code but will only sketch the methods necessary for a database that supports transactions.

(For people unfamiliar with database terminology: a set of changes to the database are grouped into a transaction. Transactions can be either committed, meaning that all the changes are written into the database, or rolled back, meaning that the changes are all discarded and the database is unchanged. See any database textbook for more information.)

Let’s assume there’s an object representing a database connection. Our goal will be to let the user write code like this:

db_connection = DatabaseConnection()
with db_connection as cursor:
    cursor.execute('insert into ...')
    cursor.execute('delete from ...')
    # ... more operations ...

The transaction should be committed if the code in the block runs flawlessly or rolled back if there’s an exception. Here’s the basic interface for DatabaseConnection that I’ll assume:

class DatabaseConnection:
    # Database interface
    def cursor(self):
        "Returns a cursor object and starts a new transaction"
    def commit(self):
        "Commits current transaction"
    def rollback(self):
        "Rolls back current transaction"

The __enter__() method is pretty easy, having only to start a new transaction. For this application the resulting cursor object would be a useful result, so the method will return it. The user can then add as cursor to their ‘with’ statement to bind the cursor to a variable name.

class DatabaseConnection:
    ...
    def __enter__(self):
        # Code to start a new transaction
        cursor = self.cursor()
        return cursor

The __exit__() method is the most complicated because it’s where most of the work has to be done. The method has to check if an exception occurred. If there was no exception, the transaction is committed. The transaction is rolled back if there was an exception.

In the code below, execution will just fall off the end of the function, returning the default value of None. None is false, so the exception will be re-raised automatically. If you wished, you could be more explicit and add a return statement at the marked location.

class DatabaseConnection:
    ...
    def __exit__(self, type, value, tb):
        if tb is None:
            # No exception, so commit
            self.commit()
        else:
            # Exception occurred, so rollback.
            self.rollback()
            # return False

The contextlib module

The contextlib module provides some functions and a decorator that are useful when writing objects for use with the ‘with’ statement.

The decorator is called contextmanager(), and lets you write a single generator function instead of defining a new class. The generator should yield exactly one value. The code up to the yield will be executed as the __enter__() method, and the value yielded will be the method’s return value that will get bound to the variable in the ‘with’ statement’s as clause, if any. The code after the yield will be executed in the __exit__() method. Any exception raised in the block will be raised by the yield statement.

Using this decorator, our database example from the previous section could be written as:

from contextlib import contextmanager

@contextmanager
def db_transaction(connection):
    cursor = connection.cursor()
    try:
        yield cursor
    except:
        connection.rollback()
        raise
    else:
        connection.commit()

db = DatabaseConnection()
with db_transaction(db) as cursor:
    ...

The contextlib module also has a nested(mgr1, mgr2, ...) function that combines a number of context managers so you don’t need to write nested ‘with’ statements. In this example, the single ‘with’ statement both starts a database transaction and acquires a thread lock:

lock = threading.Lock()
with nested (db_transaction(db), lock) as (cursor, locked):
    ...

Finally, the closing() function returns its argument so that it can be bound to a variable, and calls the argument’s .close() method at the end of the block.

import urllib, sys
from contextlib import closing

with closing(urllib.urlopen('http://www.yahoo.com')) as f:
    for line in f:
        sys.stdout.write(line)

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PEP 343 [https://peps.python.org/pep-0343/] - The “with” statement

PEP written by Guido van Rossum and Nick Coghlan; implemented by Mike Bland, Guido van Rossum, and Neal Norwitz. The PEP shows the code generated for a ‘with’ statement, which can be helpful in learning how the statement works.

The documentation for the contextlib module.

PEP 366: Explicit Relative Imports From a Main Module

Python’s -m switch allows running a module as a script. When you ran a module that was located inside a package, relative imports didn’t work correctly.

The fix for Python 2.6 adds a module.__package__ attribute. When this attribute is present, relative imports will be relative to the value of this attribute instead of the __name__ attribute.

PEP 302-style importers can then set __package__ as necessary. The runpy module that implements the -m switch now does this, so relative imports will now work correctly in scripts running from inside a package.

PEP 370: Per-user site-packages Directory

When you run Python, the module search path sys.path usually includes a directory whose path ends in "site-packages". This directory is intended to hold locally installed packages available to all users using a machine or a particular site installation.

Python 2.6 introduces a convention for user-specific site directories. The directory varies depending on the platform:

Unix and Mac OS X: ~/.local/

Windows: %APPDATA%/Python

Within this directory, there will be version-specific subdirectories, such as lib/python2.6/site-packages on Unix/Mac OS and Python26/site-packages on Windows.

If you don’t like the default directory, it can be overridden by an environment variable. PYTHONUSERBASE sets the root directory used for all Python versions supporting this feature. On Windows, the directory for application-specific data can be changed by setting the APPDATA environment variable. You can also modify the site.py file for your Python installation.

The feature can be disabled entirely by running Python with the -s option or setting the PYTHONNOUSERSITE environment variable.

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PEP 370 [https://peps.python.org/pep-0370/] - Per-user site-packages Directory

PEP written and implemented by Christian Heimes.

PEP 371: The multiprocessing Package

The new multiprocessing package lets Python programs create new processes that will perform a computation and return a result to the parent. The parent and child processes can communicate using queues and pipes, synchronize their operations using locks and semaphores, and can share simple arrays of data.

The multiprocessing module started out as an exact emulation of the threading module using processes instead of threads. That goal was discarded along the path to Python 2.6, but the general approach of the module is still similar. The fundamental class is the Process, which is passed a callable object and a collection of arguments. The start() method sets the callable running in a subprocess, after which you can call the is_alive() method to check whether the subprocess is still running and the join() method to wait for the process to exit.

Here’s a simple example where the subprocess will calculate a factorial. The function doing the calculation is written strangely so that it takes significantly longer when the input argument is a multiple of 4.

import time
from multiprocessing import Process, Queue

def factorial(queue, N):
    "Compute a factorial."
    # If N is a multiple of 4, this function will take much longer.
    if (N % 4) == 0:
        time.sleep(.05 * N/4)

    # Calculate the result
    fact = 1L
    for i in range(1, N+1):
        fact = fact * i

    # Put the result on the queue
    queue.put(fact)

if __name__ == '__main__':
    queue = Queue()

    N = 5

    p = Process(target=factorial, args=(queue, N))
    p.start()
    p.join()

    result = queue.get()
    print 'Factorial', N, '=', result

A Queue is used to communicate the result of the factorial. The Queue object is stored in a global variable. The child process will use the value of the variable when the child was created; because it’s a Queue, parent and child can use the object to communicate. (If the parent were to change the value of the global variable, the child’s value would be unaffected, and vice versa.)

Two other classes, Pool and Manager, provide higher-level interfaces. Pool will create a fixed number of worker processes, and requests can then be distributed to the workers by calling apply() or apply_async() to add a single request, and map() or map_async() to add a number of requests. The following code uses a Pool to spread requests across 5 worker processes and retrieve a list of results:

from multiprocessing import Pool

def factorial(N, dictionary):
    "Compute a factorial."
    ...
p = Pool(5)
result = p.map(factorial, range(1, 1000, 10))
for v in result:
    print v

This produces the following output:

1
39916800
51090942171709440000
8222838654177922817725562880000000
33452526613163807108170062053440751665152000000000
...

The other high-level interface, the Manager class, creates a separate server process that can hold master copies of Python data structures. Other processes can then access and modify these data structures using proxy objects. The following example creates a shared dictionary by calling the dict() method; the worker processes then insert values into the dictionary. (Locking is not done for you automatically, which doesn’t matter in this example. Manager’s methods also include Lock(), RLock(), and Semaphore() to create shared locks.)

import time
from multiprocessing import Pool, Manager

def factorial(N, dictionary):
    "Compute a factorial."
    # Calculate the result
    fact = 1L
    for i in range(1, N+1):
        fact = fact * i

    # Store result in dictionary
    dictionary[N] = fact

if __name__ == '__main__':
    p = Pool(5)
    mgr = Manager()
    d = mgr.dict()         # Create shared dictionary

    # Run tasks using the pool
    for N in range(1, 1000, 10):
        p.apply_async(factorial, (N, d))

    # Mark pool as closed -- no more tasks can be added.
    p.close()

    # Wait for tasks to exit
    p.join()

    # Output results
    for k, v in sorted(d.items()):
        print k, v

This will produce the output:

1 1
11 39916800
21 51090942171709440000
31 8222838654177922817725562880000000
41 33452526613163807108170062053440751665152000000000
51 15511187532873822802242430164693032110632597200169861120000...

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The documentation for the multiprocessing module.

PEP 371 [https://peps.python.org/pep-0371/] - Addition of the multiprocessing package

PEP written by Jesse Noller and Richard Oudkerk; implemented by Richard Oudkerk and Jesse Noller.

PEP 3101: Advanced String Formatting

In Python 3.0, the % operator is supplemented by a more powerful string formatting method, format(). Support for the str.format() method has been backported to Python 2.6.

In 2.6, both 8-bit and Unicode strings have a .format() method that treats the string as a template and takes the arguments to be formatted. The formatting template uses curly brackets ({, }) as special characters:

>>> # Substitute positional argument 0 into the string.
>>> "User ID: {0}".format("root")
'User ID: root'
>>> # Use the named keyword arguments
>>> "User ID: {uid}   Last seen: {last_login}".format(
...    uid="root",
...    last_login = "5 Mar 2008 07:20")
'User ID: root   Last seen: 5 Mar 2008 07:20'

Curly brackets can be escaped by doubling them:

>>> "Empty dict: {{}}".format()
"Empty dict: {}"

Field names can be integers indicating positional arguments, such as {0}, {1}, etc. or names of keyword arguments. You can also supply compound field names that read attributes or access dictionary keys:

>>> import sys
>>> print 'Platform: {0.platform}\nPython version: {0.version}'.format(sys)
Platform: darwin
Python version: 2.6a1+ (trunk:61261M, Mar  5 2008, 20:29:41)
[GCC 4.0.1 (Apple Computer, Inc. build 5367)]'

>>> import mimetypes
>>> 'Content-type: {0[.mp4]}'.format(mimetypes.types_map)
'Content-type: video/mp4'

Note that when using dictionary-style notation such as [.mp4], you don’t need to put any quotation marks around the string; it will look up the value using .mp4 as the key. Strings beginning with a number will be converted to an integer. You can’t write more complicated expressions inside a format string.

So far we’ve shown how to specify which field to substitute into the resulting string. The precise formatting used is also controllable by adding a colon followed by a format specifier. For example:

>>> # Field 0: left justify, pad to 15 characters
>>> # Field 1: right justify, pad to 6 characters
>>> fmt = '{0:15} ${1:>6}'
>>> fmt.format('Registration', 35)
'Registration    $    35'
>>> fmt.format('Tutorial', 50)
'Tutorial        $    50'
>>> fmt.format('Banquet', 125)
'Banquet         $   125'

Format specifiers can reference other fields through nesting:

>>> fmt = '{0:{1}}'
>>> width = 15
>>> fmt.format('Invoice #1234', width)
'Invoice #1234  '
>>> width = 35
>>> fmt.format('Invoice #1234', width)
'Invoice #1234                      '

The alignment of a field within the desired width can be specified:

Character

Effect

< (default)

Left-align

>

Right-align

^

Center

=

(For numeric types only) Pad after the sign.

Format specifiers can also include a presentation type, which controls how the value is formatted. For example, floating-point numbers can be formatted as a general number or in exponential notation:

>>> '{0:g}'.format(3.75)
'3.75'
>>> '{0:e}'.format(3.75)
'3.750000e+00'

A variety of presentation types are available. Consult the 2.6 documentation for a complete list; here’s a sample:

b

Binary. Outputs the number in base 2.

c

Character. Converts the integer to the corresponding Unicode character before printing.

d

Decimal Integer. Outputs the number in base 10.

o

Octal format. Outputs the number in base 8.

x

Hex format. Outputs the number in base 16, using lower-case letters for the digits above 9.

e

Exponent notation. Prints the number in scientific notation using the letter ‘e’ to indicate the exponent.

g

General format. This prints the number as a fixed-point number, unless the number is too large, in which case it switches to ‘e’ exponent notation.

n

Number. This is the same as ‘g’ (for floats) or ‘d’ (for integers), except that it uses the current locale setting to insert the appropriate number separator characters.

%

Percentage. Multiplies the number by 100 and displays in fixed (‘f’) format, followed by a percent sign.

Classes and types can define a __format__() method to control how they’re formatted. It receives a single argument, the format specifier:

def __format__(self, format_spec):
    if isinstance(format_spec, unicode):
        return unicode(str(self))
    else:
        return str(self)

There’s also a format() builtin that will format a single value. It calls the type’s __format__() method with the provided specifier:

>>> format(75.6564, '.2f')
'75.66'

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포맷 문자열 문법

The reference documentation for format fields.

PEP 3101 [https://peps.python.org/pep-3101/] - Advanced String Formatting

PEP written by Talin. Implemented by Eric Smith.

PEP 3105: print As a Function

The print statement becomes the print() function in Python 3.0. Making print() a function makes it possible to replace the function by doing def print(...) or importing a new function from somewhere else.

Python 2.6 has a __future__ import that removes print as language syntax, letting you use the functional form instead. For example:

>>> from __future__ import print_function
>>> print('# of entries', len(dictionary), file=sys.stderr)

The signature of the new function is:

def print(*args, sep=' ', end='\n', file=None)

The parameters are:

args: positional arguments whose values will be printed out.

sep: the separator, which will be printed between arguments.

end: the ending text, which will be printed after all of the arguments have been output.

file: the file object to which the output will be sent.

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PEP 3105 [https://peps.python.org/pep-3105/] - Make print a function

PEP written by Georg Brandl.

PEP 3110: Exception-Handling Changes

One error that Python programmers occasionally make is writing the following code:

try:
    ...
except TypeError, ValueError:  # Wrong!
    ...

The author is probably trying to catch both TypeError and ValueError exceptions, but this code actually does something different: it will catch TypeError and bind the resulting exception object to the local name "ValueError". The ValueError exception will not be caught at all. The correct code specifies a tuple of exceptions:

try:
    ...
except (TypeError, ValueError):
    ...

This error happens because the use of the comma here is ambiguous: does it indicate two different nodes in the parse tree, or a single node that’s a tuple?

Python 3.0 makes this unambiguous by replacing the comma with the word “as”. To catch an exception and store the exception object in the variable exc, you must write:

try:
    ...
except TypeError as exc:
    ...

Python 3.0 will only support the use of “as”, and therefore interprets the first example as catching two different exceptions. Python 2.6 supports both the comma and “as”, so existing code will continue to work. We therefore suggest using “as” when writing new Python code that will only be executed with 2.6.

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PEP 3110 [https://peps.python.org/pep-3110/] - Catching Exceptions in Python 3000

PEP written and implemented by Collin Winter.

PEP 3112: Byte Literals

Python 3.0 adopts Unicode as the language’s fundamental string type and denotes 8-bit literals differently, either as b'string' or using a bytes constructor. For future compatibility, Python 2.6 adds bytes as a synonym for the str type, and it also supports the b'' notation.

The 2.6 str differs from 3.0’s bytes type in various ways; most notably, the constructor is completely different. In 3.0, bytes([65, 66, 67]) is 3 elements long, containing the bytes representing ABC; in 2.6, bytes([65, 66, 67]) returns the 12-byte string representing the str() of the list.

The primary use of bytes in 2.6 will be to write tests of object type such as isinstance(x, bytes). This will help the 2to3 converter, which can’t tell whether 2.x code intends strings to contain either characters or 8-bit bytes; you can now use either bytes or str to represent your intention exactly, and the resulting code will also be correct in Python 3.0.

There’s also a __future__ import that causes all string literals to become Unicode strings. This means that \u escape sequences can be used to include Unicode characters:

from __future__ import unicode_literals

s = ('\u751f\u3080\u304e\u3000\u751f\u3054'
     '\u3081\u3000\u751f\u305f\u307e\u3054')

print len(s)               # 12 Unicode characters

At the C level, Python 3.0 will rename the existing 8-bit string type, called PyStringObject in Python 2.x, to PyBytesObject. Python 2.6 uses #define to support using the names PyBytesObject(), PyBytes_Check(), PyBytes_FromStringAndSize(), and all the other functions and macros used with strings.

Instances of the bytes type are immutable just as strings are. A new bytearray type stores a mutable sequence of bytes:

>>> bytearray([65, 66, 67])
bytearray(b'ABC')
>>> b = bytearray(u'\u21ef\u3244', 'utf-8')
>>> b
bytearray(b'\xe2\x87\xaf\xe3\x89\x84')
>>> b[0] = '\xe3'
>>> b
bytearray(b'\xe3\x87\xaf\xe3\x89\x84')
>>> unicode(str(b), 'utf-8')
u'\u31ef \u3244'

Byte arrays support most of the methods of string types, such as startswith()/endswith(), find()/rfind(), and some of the methods of lists, such as append(), pop(), and reverse().

>>> b = bytearray('ABC')
>>> b.append('d')
>>> b.append(ord('e'))
>>> b
bytearray(b'ABCde')

There’s also a corresponding C API, with PyByteArray_FromObject(), PyByteArray_FromStringAndSize(), and various other functions.

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PEP 3112 [https://peps.python.org/pep-3112/] - Bytes literals in Python 3000

PEP written by Jason Orendorff; backported to 2.6 by Christian Heimes.

PEP 3116: New I/O Library

Python’s built-in file objects support a number of methods, but file-like objects don’t necessarily support all of them. Objects that imitate files usually support read() and write(), but they may not support readline(), for example. Python 3.0 introduces a layered I/O library in the io module that separates buffering and text-handling features from the fundamental read and write operations.

There are three levels of abstract base classes provided by the io module:

RawIOBase defines raw I/O operations: read(), readinto(), write(), seek(), tell(), truncate(), and close(). Most of the methods of this class will often map to a single system call. There are also readable(), writable(), and seekable() methods for determining what operations a given object will allow.

Python 3.0 has concrete implementations of this class for files and sockets, but Python 2.6 hasn’t restructured its file and socket objects in this way.

BufferedIOBase is an abstract base class that buffers data in memory to reduce the number of system calls used, making I/O processing more efficient. It supports all of the methods of RawIOBase, and adds a raw attribute holding the underlying raw object.

There are five concrete classes implementing this ABC. BufferedWriter and BufferedReader are for objects that support write-only or read-only usage that have a seek() method for random access. BufferedRandom objects support read and write access upon the same underlying stream, and BufferedRWPair is for objects such as TTYs that have both read and write operations acting upon unconnected streams of data. The BytesIO class supports reading, writing, and seeking over an in-memory buffer.

TextIOBase: Provides functions for reading and writing strings (remember, strings will be Unicode in Python 3.0), and supporting universal newlines. TextIOBase defines the readline() method and supports iteration upon objects.

There are two concrete implementations. TextIOWrapper wraps a buffered I/O object, supporting all of the methods for text I/O and adding a buffer attribute for access to the underlying object. StringIO simply buffers everything in memory without ever writing anything to disk.

(In Python 2.6, io.StringIO is implemented in pure Python, so it’s pretty slow. You should therefore stick with the existing StringIO module or cStringIO for now. At some point Python 3.0’s io module will be rewritten into C for speed, and perhaps the C implementation will be backported to the 2.x releases.)

In Python 2.6, the underlying implementations haven’t been restructured to build on top of the io module’s classes. The module is being provided to make it easier to write code that’s forward-compatible with 3.0, and to save developers the effort of writing their own implementations of buffering and text I/O.

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PEP 3116 [https://peps.python.org/pep-3116/] - New I/O

PEP written by Daniel Stutzbach, Mike Verdone, and Guido van Rossum. Code by Guido van Rossum, Georg Brandl, Walter Doerwald, Jeremy Hylton, Martin von Löwis, Tony Lownds, and others.

PEP 3118: Revised Buffer Protocol

The buffer protocol is a C-level API that lets Python types exchange pointers into their internal representations. A memory-mapped file can be viewed as a buffer of characters, for example, and this lets another module such as re treat memory-mapped files as a string of characters to be searched.

The primary users of the buffer protocol are numeric-processing packages such as NumPy, which expose the internal representation of arrays so that callers can write data directly into an array instead of going through a slower API. This PEP updates the buffer protocol in light of experience from NumPy development, adding a number of new features such as indicating the shape of an array or locking a memory region.

The most important new C API function is PyObject_GetBuffer(PyObject *obj, Py_buffer *view, int flags), which takes an object and a set of flags, and fills in the Py_buffer structure with information about the object’s memory representation. Objects can use this operation to lock memory in place while an external caller could be modifying the contents, so there’s a corresponding PyBuffer_Release(Py_buffer *view) to indicate that the external caller is done.

The flags argument to PyObject_GetBuffer() specifies constraints upon the memory returned. Some examples are:

PyBUF_WRITABLE indicates that the memory must be writable.

PyBUF_LOCK requests a read-only or exclusive lock on the memory.

PyBUF_C_CONTIGUOUS and PyBUF_F_CONTIGUOUS requests a C-contiguous (last dimension varies the fastest) or Fortran-contiguous (first dimension varies the fastest) array layout.

Two new argument codes for PyArg_ParseTuple(), s* and z*, return locked buffer objects for a parameter.

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PEP 3118 [https://peps.python.org/pep-3118/] - Revising the buffer protocol

PEP written by Travis Oliphant and Carl Banks; implemented by Travis Oliphant.

PEP 3119: Abstract Base Classes

Some object-oriented languages such as Java support interfaces, declaring that a class has a given set of methods or supports a given access protocol. Abstract Base Classes (or ABCs) are an equivalent feature for Python. The ABC support consists of an abc module containing a metaclass called ABCMeta, special handling of this metaclass by the isinstance() and issubclass() builtins, and a collection of basic ABCs that the Python developers think will be widely useful. Future versions of Python will probably add more ABCs.

Let’s say you have a particular class and wish to know whether it supports dictionary-style access. The phrase “dictionary-style” is vague, however. It probably means that accessing items with obj[1] works. Does it imply that setting items with obj[2] = value works? Or that the object will have keys(), values(), and items() methods? What about the iterative variants such as iterkeys()? copy() and update()? Iterating over the object with iter()?

The Python 2.6 collections module includes a number of different ABCs that represent these distinctions. Iterable indicates that a class defines __iter__(), and Container means the class defines a __contains__() method and therefore supports x in y expressions. The basic dictionary interface of getting items, setting items, and keys(), values(), and items(), is defined by the MutableMapping ABC.

You can derive your own classes from a particular ABC to indicate they support that ABC’s interface:

import collections

class Storage(collections.MutableMapping):
    ...

Alternatively, you could write the class without deriving from the desired ABC and instead register the class by calling the ABC’s register() method:

import collections

class Storage:
    ...

collections.MutableMapping.register(Storage)

For classes that you write, deriving from the ABC is probably clearer. The register() method is useful when you’ve written a new ABC that can describe an existing type or class, or if you want to declare that some third-party class implements an ABC. For example, if you defined a PrintableType ABC, it’s legal to do:

# Register Python's types
PrintableType.register(int)
PrintableType.register(float)
PrintableType.register(str)

Classes should obey the semantics specified by an ABC, but Python can’t check this; it’s up to the class author to understand the ABC’s requirements and to implement the code accordingly.

To check whether an object supports a particular interface, you can now write:

def func(d):
    if not isinstance(d, collections.MutableMapping):
        raise ValueError("Mapping object expected, not %r" % d)

Don’t feel that you must now begin writing lots of checks as in the above example. Python has a strong tradition of duck-typing, where explicit type-checking is never done and code simply calls methods on an object, trusting that those methods will be there and raising an exception if they aren’t. Be judicious in checking for ABCs and only do it where it’s absolutely necessary.

You can write your own ABCs by using abc.ABCMeta as the metaclass in a class definition:

from abc import ABCMeta, abstractmethod

class Drawable():
    __metaclass__ = ABCMeta

    @abstractmethod
    def draw(self, x, y, scale=1.0):
        pass

    def draw_doubled(self, x, y):
        self.draw(x, y, scale=2.0)

class Square(Drawable):
    def draw(self, x, y, scale):
        ...

In the Drawable ABC above, the draw_doubled() method renders the object at twice its size and can be implemented in terms of other methods described in Drawable. Classes implementing this ABC therefore don’t need to provide their own implementation of draw_doubled(), though they can do so. An implementation of draw() is necessary, though; the ABC can’t provide a useful generic implementation.

You can apply the @abstractmethod decorator to methods such as draw() that must be implemented; Python will then raise an exception for classes that don’t define the method. Note that the exception is only raised when you actually try to create an instance of a subclass lacking the method:

>>> class Circle(Drawable):
...     pass
...
>>> c = Circle()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class Circle with abstract methods draw
>>>

Abstract data attributes can be declared using the @abstractproperty decorator:

from abc import abstractproperty
...

@abstractproperty
def readonly(self):
   return self._x

Subclasses must then define a readonly() property.

더 보기

PEP 3119 [https://peps.python.org/pep-3119/] - Introducing Abstract Base Classes

PEP written by Guido van Rossum and Talin. Implemented by Guido van Rossum. Backported to 2.6 by Benjamin Aranguren, with Alex Martelli.

PEP 3127: Integer Literal Support and Syntax

Python 3.0 changes the syntax for octal (base-8) integer literals, prefixing them with “0o” or “0O” instead of a leading zero, and adds support for binary (base-2) integer literals, signalled by a “0b” or “0B” prefix.

Python 2.6 doesn’t drop support for a leading 0 signalling an octal number, but it does add support for “0o” and “0b”:

>>> 0o21, 2*8 + 1
(17, 17)
>>> 0b101111
47

The oct() builtin still returns numbers prefixed with a leading zero, and a new bin() builtin returns the binary representation for a number:

>>> oct(42)
'052'
>>> future_builtins.oct(42)
'0o52'
>>> bin(173)
'0b10101101'

The int() and long() builtins will now accept the “0o” and “0b” prefixes when base-8 or base-2 are requested, or when the base argument is zero (signalling that the base used should be determined from the string):

>>> int ('0o52', 0)
42
>>> int('1101', 2)
13
>>> int('0b1101', 2)
13
>>> int('0b1101', 0)
13

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PEP 3127 [https://peps.python.org/pep-3127/] - Integer Literal Support and Syntax

PEP written by Patrick Maupin; backported to 2.6 by Eric Smith.

PEP 3129: Class Decorators

Decorators have been extended from functions to classes. It’s now legal to write:

@foo
@bar
class A:
  pass

This is equivalent to:

class A:
  pass

A = foo(bar(A))

더 보기

PEP 3129 [https://peps.python.org/pep-3129/] - Class Decorators

PEP written by Collin Winter.

PEP 3141: A Type Hierarchy for Numbers

Python 3.0 adds several abstract base classes for numeric types inspired by Scheme’s numeric tower. These classes were backported to 2.6 as the numbers module.

The most general ABC is Number. It defines no operations at all, and only exists to allow checking if an object is a number by doing isinstance(obj, Number).

Complex is a subclass of Number. Complex numbers can undergo the basic operations of addition, subtraction, multiplication, division, and exponentiation, and you can retrieve the real and imaginary parts and obtain a number’s conjugate. Python’s built-in complex type is an implementation of Complex.

Real further derives from Complex, and adds operations that only work on real numbers: floor(), trunc(), rounding, taking the remainder mod N, floor division, and comparisons.

Rational numbers derive from Real, have numerator and denominator properties, and can be converted to floats. Python 2.6 adds a simple rational-number class, Fraction, in the fractions module. (It’s called Fraction instead of Rational to avoid a name clash with numbers.Rational.)

Integral numbers derive from Rational, and can be shifted left and right with << and >>, combined using bitwise operations such as & and |, and can be used as array indexes and slice boundaries.

In Python 3.0, the PEP slightly redefines the existing builtins round(), math.floor(), math.ceil(), and adds a new one, math.trunc(), that’s been backported to Python 2.6. math.trunc() rounds toward zero, returning the closest Integral that’s between the function’s argument and zero.

더 보기

PEP 3141 [https://peps.python.org/pep-3141/] - A Type Hierarchy for Numbers

PEP written by Jeffrey Yasskin.

Scheme’s numerical tower [https://www.gnu.org/software/guile/manual/html_node/Numerical-Tower.html#Numerical-Tower], from the Guile manual.

Scheme’s number datatypes [https://conservatory.scheme.org/schemers/Documents/Standards/R5RS/HTML/r5rs-Z-H-9.html#%_sec_6.2] from the R5RS Scheme specification.

The fractions Module

To fill out the hierarchy of numeric types, the fractions module provides a rational-number class. Rational numbers store their values as a numerator and denominator forming a fraction, and can exactly represent numbers such as 2/3 that floating-point numbers can only approximate.

The Fraction constructor takes two Integral values that will be the numerator and denominator of the resulting fraction.

>>> from fractions import Fraction
>>> a = Fraction(2, 3)
>>> b = Fraction(2, 5)
>>> float(a), float(b)
(0.66666666666666663, 0.40000000000000002)
>>> a+b
Fraction(16, 15)
>>> a/b
Fraction(5, 3)

For converting floating-point numbers to rationals, the float type now has an as_integer_ratio() method that returns the numerator and denominator for a fraction that evaluates to the same floating-point value:

>>> (2.5) .as_integer_ratio()
(5, 2)
>>> (3.1415) .as_integer_ratio()
(7074029114692207L, 2251799813685248L)
>>> (1./3) .as_integer_ratio()
(6004799503160661L, 18014398509481984L)

Note that values that can only be approximated by floating-point numbers, such as 1./3, are not simplified to the number being approximated; the fraction attempts to match the floating-point value exactly.

The fractions module is based upon an implementation by Sjoerd Mullender that was in Python’s Demo/classes/ directory for a long time. This implementation was significantly updated by Jeffrey Yasskin.

Other Language Changes

Some smaller changes made to the core Python language are:

Directories and zip archives containing a __main__.py file can now be executed directly by passing their name to the interpreter. The directory or zip archive is automatically inserted as the first entry in sys.path. (Suggestion and initial patch by Andy Chu, subsequently revised by Phillip J. Eby and Nick Coghlan; bpo-1739468 [https://bugs.python.org/issue?@action=redirect&bpo=1739468].)

The hasattr() function was catching and ignoring all errors, under the assumption that they meant a __getattr__() method was failing somehow and the return value of hasattr() would therefore be False. This logic shouldn’t be applied to KeyboardInterrupt and SystemExit, however; Python 2.6 will no longer discard such exceptions when hasattr() encounters them. (Fixed by Benjamin Peterson; bpo-2196 [https://bugs.python.org/issue?@action=redirect&bpo=2196].)

When calling a function using the ** syntax to provide keyword arguments, you are no longer required to use a Python dictionary; any mapping will now work:

>>> def f(**kw):
...    print sorted(kw)
...
>>> ud=UserDict.UserDict()
>>> ud['a'] = 1
>>> ud['b'] = 'string'
>>> f(**ud)
['a', 'b']

(Contributed by Alexander Belopolsky; bpo-1686487 [https://bugs.python.org/issue?@action=redirect&bpo=1686487].)

It’s also become legal to provide keyword arguments after a *args argument to a function call.

>>> def f(*args, **kw):
...     print args, kw
...
>>> f(1,2,3, *(4,5,6), keyword=13)
(1, 2, 3, 4, 5, 6) {'keyword': 13}

Previously this would have been a syntax error. (Contributed by Amaury Forgeot d’Arc; bpo-3473 [https://bugs.python.org/issue?@action=redirect&bpo=3473].)

A new builtin, next(iterator, [default]) returns the next item from the specified iterator. If the default argument is supplied, it will be returned if iterator has been exhausted; otherwise, the StopIteration exception will be raised. (Backported in bpo-2719 [https://bugs.python.org/issue?@action=redirect&bpo=2719].)

Tuples now have index() and count() methods matching the list type’s index() and count() methods:

>>> t = (0,1,2,3,4,0,1,2)
>>> t.index(3)
3
>>> t.count(0)
2

(Contributed by Raymond Hettinger)

The built-in types now have improved support for extended slicing syntax, accepting various combinations of (start, stop, step). Previously, the support was partial and certain corner cases wouldn’t work. (Implemented by Thomas Wouters.)

Properties now have three attributes, getter, setter and deleter, that are decorators providing useful shortcuts for adding a getter, setter or deleter function to an existing property. You would use them like this:

class C(object):
    @property
    def x(self):
        return self._x

    @x.setter
    def x(self, value):
        self._x = value

    @x.deleter
    def x(self):
        del self._x

class D(C):
    @C.x.getter
    def x(self):
        return self._x * 2

    @x.setter
    def x(self, value):
        self._x = value / 2

Several methods of the built-in set types now accept multiple iterables: intersection(), intersection_update(), union(), update(), difference() and difference_update().

>>> s=set('1234567890')
>>> s.intersection('abc123', 'cdf246')  # Intersection between all inputs
set(['2'])
>>> s.difference('246', '789')
set(['1', '0', '3', '5'])

(Contributed by Raymond Hettinger.)

Many floating-point features were added. The float() function will now turn the string nan into an IEEE 754 Not A Number value, and +inf and -inf into positive or negative infinity. This works on any platform with IEEE 754 semantics. (Contributed by Christian Heimes; bpo-1635 [https://bugs.python.org/issue?@action=redirect&bpo=1635].)

Other functions in the math module, isinf() and isnan(), return true if their floating-point argument is infinite or Not A Number. (bpo-1640 [https://bugs.python.org/issue?@action=redirect&bpo=1640])

Conversion functions were added to convert floating-point numbers into hexadecimal strings (bpo-3008 [https://bugs.python.org/issue?@action=redirect&bpo=3008]). These functions convert floats to and from a string representation without introducing rounding errors from the conversion between decimal and binary. Floats have a hex() method that returns a string representation, and the float.fromhex() method converts a string back into a number:

>>> a = 3.75
>>> a.hex()
'0x1.e000000000000p+1'
>>> float.fromhex('0x1.e000000000000p+1')
3.75
>>> b=1./3
>>> b.hex()
'0x1.5555555555555p-2'

A numerical nicety: when creating a complex number from two floats on systems that support signed zeros (-0 and +0), the complex() constructor will now preserve the sign of the zero. (Fixed by Mark T. Dickinson; bpo-1507 [https://bugs.python.org/issue?@action=redirect&bpo=1507].)

Classes that inherit a __hash__() method from a parent class can set __hash__ = None to indicate that the class isn’t hashable. This will make hash(obj) raise a TypeError and the class will not be indicated as implementing the Hashable ABC.

You should do this when you’ve defined a __cmp__() or __eq__() method that compares objects by their value rather than by identity. All objects have a default hash method that uses id(obj) as the hash value. There’s no tidy way to remove the __hash__() method inherited from a parent class, so assigning None was implemented as an override. At the C level, extensions can set tp_hash to PyObject_HashNotImplemented(). (Fixed by Nick Coghlan and Amaury Forgeot d’Arc; bpo-2235 [https://bugs.python.org/issue?@action=redirect&bpo=2235].)

The GeneratorExit exception now subclasses BaseException instead of Exception. This means that an exception handler that does except Exception: will not inadvertently catch GeneratorExit. (Contributed by Chad Austin; bpo-1537 [https://bugs.python.org/issue?@action=redirect&bpo=1537].)

Generator objects now have a gi_code attribute that refers to the original code object backing the generator. (Contributed by Collin Winter; bpo-1473257 [https://bugs.python.org/issue?@action=redirect&bpo=1473257].)

The compile() built-in function now accepts keyword arguments as well as positional parameters. (Contributed by Thomas Wouters; bpo-1444529 [https://bugs.python.org/issue?@action=redirect&bpo=1444529].)

The complex() constructor now accepts strings containing parenthesized complex numbers, meaning that complex(repr(cplx)) will now round-trip values. For example, complex('(3+4j)') now returns the value (3+4j). (bpo-1491866 [https://bugs.python.org/issue?@action=redirect&bpo=1491866])

The string translate() method now accepts None as the translation table parameter, which is treated as the identity transformation. This makes it easier to carry out operations that only delete characters. (Contributed by Bengt Richter and implemented by Raymond Hettinger; bpo-1193128 [https://bugs.python.org/issue?@action=redirect&bpo=1193128].)

The built-in dir() function now checks for a __dir__() method on the objects it receives. This method must return a list of strings containing the names of valid attributes for the object, and lets the object control the value that dir() produces. Objects that have __getattr__() or __getattribute__() methods can use this to advertise pseudo-attributes they will honor. (bpo-1591665 [https://bugs.python.org/issue?@action=redirect&bpo=1591665])

Instance method objects have new attributes for the object and function comprising the method; the new synonym for im_self is __self__, and im_func is also available as __func__. The old names are still supported in Python 2.6, but are gone in 3.0.

An obscure change: when you use the locals() function inside a class statement, the resulting dictionary no longer returns free variables. (Free variables, in this case, are variables referenced in the class statement that aren’t attributes of the class.)

Optimizations

The warnings module has been rewritten in C. This makes it possible to invoke warnings from the parser, and may also make the interpreter’s startup faster. (Contributed by Neal Norwitz and Brett Cannon; bpo-1631171 [https://bugs.python.org/issue?@action=redirect&bpo=1631171].)

Type objects now have a cache of methods that can reduce the work required to find the correct method implementation for a particular class; once cached, the interpreter doesn’t need to traverse base classes to figure out the right method to call. The cache is cleared if a base class or the class itself is modified, so the cache should remain correct even in the face of Python’s dynamic nature. (Original optimization implemented by Armin Rigo, updated for Python 2.6 by Kevin Jacobs; bpo-1700288 [https://bugs.python.org/issue?@action=redirect&bpo=1700288].)

By default, this change is only applied to types that are included with the Python core. Extension modules may not necessarily be compatible with this cache, so they must explicitly add Py_TPFLAGS_HAVE_VERSION_TAG to the module’s tp_flags field to enable the method cache. (To be compatible with the method cache, the extension module’s code must not directly access and modify the tp_dict member of any of the types it implements. Most modules don’t do this, but it’s impossible for the Python interpreter to determine that. See bpo-1878 [https://bugs.python.org/issue?@action=redirect&bpo=1878] for some discussion.)

Function calls that use keyword arguments are significantly faster by doing a quick pointer comparison, usually saving the time of a full string comparison. (Contributed by Raymond Hettinger, after an initial implementation by Antoine Pitrou; bpo-1819 [https://bugs.python.org/issue?@action=redirect&bpo=1819].)

All of the functions in the struct module have been rewritten in C, thanks to work at the Need For Speed sprint. (Contributed by Raymond Hettinger.)

Some of the standard built-in types now set a bit in their type objects. This speeds up checking whether an object is a subclass of one of these types. (Contributed by Neal Norwitz.)

Unicode strings now use faster code for detecting whitespace and line breaks; this speeds up the split() method by about 25% and splitlines() by 35%. (Contributed by Antoine Pitrou.) Memory usage is reduced by using pymalloc for the Unicode string’s data.

The with statement now stores the __exit__() method on the stack, producing a small speedup. (Implemented by Jeffrey Yasskin.)

To reduce memory usage, the garbage collector will now clear internal free lists when garbage-collecting the highest generation of objects. This may return memory to the operating system sooner.

Interpreter Changes

Two command-line options have been reserved for use by other Python implementations. The -J switch has been reserved for use by Jython for Jython-specific options, such as switches that are passed to the underlying JVM. -X has been reserved for options specific to a particular implementation of Python such as CPython, Jython, or IronPython. If either option is used with Python 2.6, the interpreter will report that the option isn’t currently used.

Python can now be prevented from writing .pyc or .pyo files by supplying the -B switch to the Python interpreter, or by setting the PYTHONDONTWRITEBYTECODE environment variable before running the interpreter. This setting is available to Python programs as the sys.dont_write_bytecode variable, and Python code can change the value to modify the interpreter’s behaviour. (Contributed by Neal Norwitz and Georg Brandl.)

The encoding used for standard input, output, and standard error can be specified by setting the PYTHONIOENCODING environment variable before running the interpreter. The value should be a string in the form <encoding> or <encoding>:<errorhandler>. The encoding part specifies the encoding’s name, e.g. utf-8 or latin-1; the optional errorhandler part specifies what to do with characters that can’t be handled by the encoding, and should be one of “error”, “ignore”, or “replace”. (Contributed by Martin von Löwis.)

New and Improved Modules

As in every release, Python’s standard library received a number of enhancements and bug fixes. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the Misc/NEWS file in the source tree for a more complete list of changes, or look through the Subversion logs for all the details.

The asyncore and asynchat modules are being actively maintained again, and a number of patches and bugfixes were applied. (Maintained by Josiah Carlson; see bpo-1736190 [https://bugs.python.org/issue?@action=redirect&bpo=1736190] for one patch.)

The bsddb module also has a new maintainer, Jesús Cea Avión, and the package is now available as a standalone package. The web page for the package is www.jcea.es/programacion/pybsddb.htm [https://www.jcea.es/programacion/pybsddb.htm]. The plan is to remove the package from the standard library in Python 3.0, because its pace of releases is much more frequent than Python’s.

The bsddb.dbshelve module now uses the highest pickling protocol available, instead of restricting itself to protocol 1. (Contributed by W. Barnes.)

The cgi module will now read variables from the query string of an HTTP POST request. This makes it possible to use form actions with URLs that include query strings such as “/cgi-bin/add.py?category=1”. (Contributed by Alexandre Fiori and Nubis; bpo-1817 [https://bugs.python.org/issue?@action=redirect&bpo=1817].)

The parse_qs() and parse_qsl() functions have been relocated from the cgi module to the urlparse module. The versions still available in the cgi module will trigger PendingDeprecationWarning messages in 2.6 (bpo-600362 [https://bugs.python.org/issue?@action=redirect&bpo=600362]).

The cmath module underwent extensive revision, contributed by Mark Dickinson and Christian Heimes. Five new functions were added:

polar() converts a complex number to polar form, returning the modulus and argument of the complex number.

rect() does the opposite, turning a modulus, argument pair back into the corresponding complex number.

phase() returns the argument (also called the angle) of a complex number.

isnan() returns True if either the real or imaginary part of its argument is a NaN.

isinf() returns True if either the real or imaginary part of its argument is infinite.

The revisions also improved the numerical soundness of the cmath module. For all functions, the real and imaginary parts of the results are accurate to within a few units of least precision (ulps) whenever possible. See bpo-1381 [https://bugs.python.org/issue?@action=redirect&bpo=1381] for the details. The branch cuts for asinh(), atanh(): and atan() have also been corrected.

The tests for the module have been greatly expanded; nearly 2000 new test cases exercise the algebraic functions.

On IEEE 754 platforms, the cmath module now handles IEEE 754 special values and floating-point exceptions in a manner consistent with Annex ‘G’ of the C99 standard.

A new data type in the collections module: namedtuple(typename, fieldnames) is a factory function that creates subclasses of the standard tuple whose fields are accessible by name as well as index. For example:

>>> var_type = collections.namedtuple('variable',
...             'id name type size')
>>> # Names are separated by spaces or commas.
>>> # 'id, name, type, size' would also work.
>>> var_type._fields
('id', 'name', 'type', 'size')

>>> var = var_type(1, 'frequency', 'int', 4)
>>> print var[0], var.id    # Equivalent
1 1
>>> print var[2], var.type  # Equivalent
int int
>>> var._asdict()
{'size': 4, 'type': 'int', 'id': 1, 'name': 'frequency'}
>>> v2 = var._replace(name='amplitude')
>>> v2
variable(id=1, name='amplitude', type='int', size=4)

Several places in the standard library that returned tuples have been modified to return namedtuple() instances. For example, the Decimal.as_tuple() method now returns a named tuple with sign, digits, and exponent fields.

(Contributed by Raymond Hettinger.)

Another change to the collections module is that the deque type now supports an optional maxlen parameter; if supplied, the deque’s size will be restricted to no more than maxlen items. Adding more items to a full deque causes old items to be discarded.

>>> from collections import deque
>>> dq=deque(maxlen=3)
>>> dq
deque([], maxlen=3)
>>> dq.append(1); dq.append(2); dq.append(3)
>>> dq
deque([1, 2, 3], maxlen=3)
>>> dq.append(4)
>>> dq
deque([2, 3, 4], maxlen=3)

(Contributed by Raymond Hettinger.)

The Cookie module’s Morsel objects now support an httponly attribute. In some browsers. cookies with this attribute set cannot be accessed or manipulated by JavaScript code. (Contributed by Arvin Schnell; bpo-1638033 [https://bugs.python.org/issue?@action=redirect&bpo=1638033].)

A new window method in the curses module, chgat(), changes the display attributes for a certain number of characters on a single line. (Contributed by Fabian Kreutz.)

# Boldface text starting at y=0,x=21
# and affecting the rest of the line.
stdscr.chgat(0, 21, curses.A_BOLD)

The Textbox class in the curses.textpad module now supports editing in insert mode as well as overwrite mode. Insert mode is enabled by supplying a true value for the insert_mode parameter when creating the Textbox instance.

The datetime module’s strftime() methods now support a %f format code that expands to the number of microseconds in the object, zero-padded on the left to six places. (Contributed by Skip Montanaro; bpo-1158 [https://bugs.python.org/issue?@action=redirect&bpo=1158].)

The decimal module was updated to version 1.66 of the General Decimal Specification [https://speleotrove.com/decimal/decarith.html]. New features include some methods for some basic mathematical functions such as exp() and log10():

>>> Decimal(1).exp()
Decimal("2.718281828459045235360287471")
>>> Decimal("2.7182818").ln()
Decimal("0.9999999895305022877376682436")
>>> Decimal(1000).log10()
Decimal("3")

The as_tuple() method of Decimal objects now returns a named tuple with sign, digits, and exponent fields.

(Implemented by Facundo Batista and Mark Dickinson. Named tuple support added by Raymond Hettinger.)

The difflib module’s SequenceMatcher class now returns named tuples representing matches, with a, b, and size attributes. (Contributed by Raymond Hettinger.)

An optional timeout parameter, specifying a timeout measured in seconds, was added to the ftplib.FTP class constructor as well as the connect() method. (Added by Facundo Batista.) Also, the FTP class’s storbinary() and storlines() now take an optional callback parameter that will be called with each block of data after the data has been sent. (Contributed by Phil Schwartz; bpo-1221598 [https://bugs.python.org/issue?@action=redirect&bpo=1221598].)

The reduce() built-in function is also available in the functools module. In Python 3.0, the builtin has been dropped and reduce() is only available from functools; currently there are no plans to drop the builtin in the 2.x series. (Patched by Christian Heimes; bpo-1739906 [https://bugs.python.org/issue?@action=redirect&bpo=1739906].)

When possible, the getpass module will now use /dev/tty to print a prompt message and read the password, falling back to standard error and standard input. If the password may be echoed to the terminal, a warning is printed before the prompt is displayed. (Contributed by Gregory P. Smith.)

The glob.glob() function can now return Unicode filenames if a Unicode path was used and Unicode filenames are matched within the directory. (bpo-1001604 [https://bugs.python.org/issue?@action=redirect&bpo=1001604])

A new function in the heapq module, merge(iter1, iter2, ...), takes any number of iterables returning data in sorted order, and returns a new generator that returns the contents of all the iterators, also in sorted order. For example:

>>> list(heapq.merge([1, 3, 5, 9], [2, 8, 16]))
[1, 2, 3, 5, 8, 9, 16]

Another new function, heappushpop(heap, item), pushes item onto heap, then pops off and returns the smallest item. This is more efficient than making a call to heappush() and then heappop().

heapq is now implemented to only use less-than comparison, instead of the less-than-or-equal comparison it previously used. This makes heapq’s usage of a type match the list.sort() method. (Contributed by Raymond Hettinger.)

An optional timeout parameter, specifying a timeout measured in seconds, was added to the httplib.HTTPConnection and HTTPSConnection class constructors. (Added by Facundo Batista.)

Most of the inspect module’s functions, such as getmoduleinfo() and getargs(), now return named tuples. In addition to behaving like tuples, the elements of the return value can also be accessed as attributes. (Contributed by Raymond Hettinger.)

Some new functions in the module include isgenerator(), isgeneratorfunction(), and isabstract().

The itertools module gained several new functions.

izip_longest(iter1, iter2, ...[, fillvalue]) makes tuples from each of the elements; if some of the iterables are shorter than others, the missing values are set to fillvalue. For example:

>>> tuple(itertools.izip_longest([1,2,3], [1,2,3,4,5]))
((1, 1), (2, 2), (3, 3), (None, 4), (None, 5))

product(iter1, iter2, ..., [repeat=N]) returns the Cartesian product of the supplied iterables, a set of tuples containing every possible combination of the elements returned from each iterable.

>>> list(itertools.product([1,2,3], [4,5,6]))
[(1, 4), (1, 5), (1, 6),
 (2, 4), (2, 5), (2, 6),
 (3, 4), (3, 5), (3, 6)]

The optional repeat keyword argument is used for taking the product of an iterable or a set of iterables with themselves, repeated N times. With a single iterable argument, N-tuples are returned:

>>> list(itertools.product([1,2], repeat=3))
[(1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 2),
 (2, 1, 1), (2, 1, 2), (2, 2, 1), (2, 2, 2)]

With two iterables, 2N-tuples are returned.

>>> list(itertools.product([1,2], [3,4], repeat=2))
[(1, 3, 1, 3), (1, 3, 1, 4), (1, 3, 2, 3), (1, 3, 2, 4),
 (1, 4, 1, 3), (1, 4, 1, 4), (1, 4, 2, 3), (1, 4, 2, 4),
 (2, 3, 1, 3), (2, 3, 1, 4), (2, 3, 2, 3), (2, 3, 2, 4),
 (2, 4, 1, 3), (2, 4, 1, 4), (2, 4, 2, 3), (2, 4, 2, 4)]

combinations(iterable, r) returns sub-sequences of length r from the elements of iterable.

>>> list(itertools.combinations('123', 2))
[('1', '2'), ('1', '3'), ('2', '3')]
>>> list(itertools.combinations('123', 3))
[('1', '2', '3')]
>>> list(itertools.combinations('1234', 3))
[('1', '2', '3'), ('1', '2', '4'),
 ('1', '3', '4'), ('2', '3', '4')]

permutations(iter[, r]) returns all the permutations of length r of the iterable’s elements. If r is not specified, it will default to the number of elements produced by the iterable.

>>> list(itertools.permutations([1,2,3,4], 2))
[(1, 2), (1, 3), (1, 4),
 (2, 1), (2, 3), (2, 4),
 (3, 1), (3, 2), (3, 4),
 (4, 1), (4, 2), (4, 3)]

itertools.chain(*iterables) is an existing function in itertools that gained a new constructor in Python 2.6. itertools.chain.from_iterable(iterable) takes a single iterable that should return other iterables. chain() will then return all the elements of the first iterable, then all the elements of the second, and so on.

>>> list(itertools.chain.from_iterable([[1,2,3], [4,5,6]]))
[1, 2, 3, 4, 5, 6]

(All contributed by Raymond Hettinger.)

The logging module’s FileHandler class and its subclasses WatchedFileHandler, RotatingFileHandler, and TimedRotatingFileHandler now have an optional delay parameter to their constructors. If delay is true, opening of the log file is deferred until the first emit() call is made. (Contributed by Vinay Sajip.)

TimedRotatingFileHandler also has a utc constructor parameter. If the argument is true, UTC time will be used in determining when midnight occurs and in generating filenames; otherwise local time will be used.

Several new functions were added to the math module:

isinf() and isnan() determine whether a given float is a (positive or negative) infinity or a NaN (Not a Number), respectively.

copysign() copies the sign bit of an IEEE 754 number, returning the absolute value of x combined with the sign bit of y. For example, math.copysign(1, -0.0) returns -1.0. (Contributed by Christian Heimes.)

factorial() computes the factorial of a number. (Contributed by Raymond Hettinger; bpo-2138 [https://bugs.python.org/issue?@action=redirect&bpo=2138].)

fsum() adds up the stream of numbers from an iterable, and is careful to avoid loss of precision through using partial sums. (Contributed by Jean Brouwers, Raymond Hettinger, and Mark Dickinson; bpo-2819 [https://bugs.python.org/issue?@action=redirect&bpo=2819].)

acosh(), asinh() and atanh() compute the inverse hyperbolic functions.

log1p() returns the natural logarithm of 1+x (base e).

trunc() rounds a number toward zero, returning the closest Integral that’s between the function’s argument and zero. Added as part of the backport of PEP 3141’s type hierarchy for numbers.

The math module has been improved to give more consistent behaviour across platforms, especially with respect to handling of floating-point exceptions and IEEE 754 special values.

Whenever possible, the module follows the recommendations of the C99 standard about 754’s special values. For example, sqrt(-1.) should now give a ValueError across almost all platforms, while sqrt(float('NaN')) should return a NaN on all IEEE 754 platforms. Where Annex ‘F’ of the C99 standard recommends signaling ‘divide-by-zero’ or ‘invalid’, Python will raise ValueError. Where Annex ‘F’ of the C99 standard recommends signaling ‘overflow’, Python will raise OverflowError. (See bpo-711019 [https://bugs.python.org/issue?@action=redirect&bpo=711019] and bpo-1640 [https://bugs.python.org/issue?@action=redirect&bpo=1640].)

(Contributed by Christian Heimes and Mark Dickinson.)

mmap objects now have a rfind() method that searches for a substring beginning at the end of the string and searching backwards. The find() method also gained an end parameter giving an index at which to stop searching. (Contributed by John Lenton.)

The operator module gained a methodcaller() function that takes a name and an optional set of arguments, returning a callable that will call the named function on any arguments passed to it. For example:

>>> # Equivalent to lambda s: s.replace('old', 'new')
>>> replacer = operator.methodcaller('replace', 'old', 'new')
>>> replacer('old wine in old bottles')
'new wine in new bottles'

(Contributed by Georg Brandl, after a suggestion by Gregory Petrosyan.)

The attrgetter() function now accepts dotted names and performs the corresponding attribute lookups:

>>> inst_name = operator.attrgetter(
...        '__class__.__name__')
>>> inst_name('')
'str'
>>> inst_name(help)
'_Helper'

(Contributed by Georg Brandl, after a suggestion by Barry Warsaw.)

The os module now wraps several new system calls. fchmod(fd, mode) and fchown(fd, uid, gid) change the mode and ownership of an opened file, and lchmod(path, mode) changes the mode of a symlink. (Contributed by Georg Brandl and Christian Heimes.)

chflags() and lchflags() are wrappers for the corresponding system calls (where they’re available), changing the flags set on a file. Constants for the flag values are defined in the stat module; some possible values include UF_IMMUTABLE to signal the file may not be changed and UF_APPEND to indicate that data can only be appended to the file. (Contributed by M. Levinson.)

os.closerange(low, high) efficiently closes all file descriptors from low to high, ignoring any errors and not including high itself. This function is now used by the subprocess module to make starting processes faster. (Contributed by Georg Brandl; bpo-1663329 [https://bugs.python.org/issue?@action=redirect&bpo=1663329].)

The os.environ object’s clear() method will now unset the environment variables using os.unsetenv() in addition to clearing the object’s keys. (Contributed by Martin Horcicka; bpo-1181 [https://bugs.python.org/issue?@action=redirect&bpo=1181].)

The os.walk() function now has a followlinks parameter. If set to True, it will follow symlinks pointing to directories and visit the directory’s contents. For backward compatibility, the parameter’s default value is false. Note that the function can fall into an infinite recursion if there’s a symlink that points to a parent directory. (bpo-1273829 [https://bugs.python.org/issue?@action=redirect&bpo=1273829])

In the os.path module, the splitext() function has been changed to not split on leading period characters. This produces better results when operating on Unix’s dot-files. For example, os.path.splitext('.ipython') now returns ('.ipython', '') instead of ('', '.ipython'). (bpo-1115886 [https://bugs.python.org/issue?@action=redirect&bpo=1115886])

A new function, os.path.relpath(path, start='.'), returns a relative path from the start path, if it’s supplied, or from the current working directory to the destination path. (Contributed by Richard Barran; bpo-1339796 [https://bugs.python.org/issue?@action=redirect&bpo=1339796].)

On Windows, os.path.expandvars() will now expand environment variables given in the form “%var%”, and “~user” will be expanded into the user’s home directory path. (Contributed by Josiah Carlson; bpo-957650 [https://bugs.python.org/issue?@action=redirect&bpo=957650].)

The Python debugger provided by the pdb module gained a new command: “run” restarts the Python program being debugged and can optionally take new command-line arguments for the program. (Contributed by Rocky Bernstein; bpo-1393667 [https://bugs.python.org/issue?@action=redirect&bpo=1393667].)

The pdb.post_mortem() function, used to begin debugging a traceback, will now use the traceback returned by sys.exc_info() if no traceback is supplied. (Contributed by Facundo Batista; bpo-1106316 [https://bugs.python.org/issue?@action=redirect&bpo=1106316].)

The pickletools module now has an optimize() function that takes a string containing a pickle and removes some unused opcodes, returning a shorter pickle that contains the same data structure. (Contributed by Raymond Hettinger.)

A get_data() function was added to the pkgutil module that returns the contents of resource files included with an installed Python package. For example:

>>> import pkgutil
>>> print pkgutil.get_data('test', 'exception_hierarchy.txt')
BaseException
 +-- SystemExit
 +-- KeyboardInterrupt
 +-- GeneratorExit
 +-- Exception
      +-- StopIteration
      +-- StandardError
 ...

(Contributed by Paul Moore; bpo-2439 [https://bugs.python.org/issue?@action=redirect&bpo=2439].)

The pyexpat module’s Parser objects now allow setting their buffer_size attribute to change the size of the buffer used to hold character data. (Contributed by Achim Gaedke; bpo-1137 [https://bugs.python.org/issue?@action=redirect&bpo=1137].)

The Queue module now provides queue variants that retrieve entries in different orders. The PriorityQueue class stores queued items in a heap and retrieves them in priority order, and LifoQueue retrieves the most recently added entries first, meaning that it behaves like a stack. (Contributed by Raymond Hettinger.)

The random module’s Random objects can now be pickled on a 32-bit system and unpickled on a 64-bit system, and vice versa. Unfortunately, this change also means that Python 2.6’s Random objects can’t be unpickled correctly on earlier versions of Python. (Contributed by Shawn Ligocki; bpo-1727780 [https://bugs.python.org/issue?@action=redirect&bpo=1727780].)

The new triangular(low, high, mode) function returns random numbers following a triangular distribution. The returned values are between low and high, not including high itself, and with mode as the most frequently occurring value in the distribution. (Contributed by Wladmir van der Laan and Raymond Hettinger; bpo-1681432 [https://bugs.python.org/issue?@action=redirect&bpo=1681432].)

Long regular expression searches carried out by the re module will check for signals being delivered, so time-consuming searches can now be interrupted. (Contributed by Josh Hoyt and Ralf Schmitt; bpo-846388 [https://bugs.python.org/issue?@action=redirect&bpo=846388].)

The regular expression module is implemented by compiling bytecodes for a tiny regex-specific virtual machine. Untrusted code could create malicious strings of bytecode directly and cause crashes, so Python 2.6 includes a verifier for the regex bytecode. (Contributed by Guido van Rossum from work for Google App Engine; bpo-3487 [https://bugs.python.org/issue?@action=redirect&bpo=3487].)

The rlcompleter module’s Completer.complete() method will now ignore exceptions triggered while evaluating a name. (Fixed by Lorenz Quack; bpo-2250 [https://bugs.python.org/issue?@action=redirect&bpo=2250].)

The sched module’s scheduler instances now have a read-only queue attribute that returns the contents of the scheduler’s queue, represented as a list of named tuples with the fields (time, priority, action, argument). (Contributed by Raymond Hettinger; bpo-1861 [https://bugs.python.org/issue?@action=redirect&bpo=1861].)

The select module now has wrapper functions for the Linux epoll() and BSD kqueue() system calls. modify() method was added to the existing poll objects; pollobj.modify(fd, eventmask) takes a file descriptor or file object and an event mask, modifying the recorded event mask for that file. (Contributed by Christian Heimes; bpo-1657 [https://bugs.python.org/issue?@action=redirect&bpo=1657].)

The shutil.copytree() function now has an optional ignore argument that takes a callable object. This callable will receive each directory path and a list of the directory’s contents, and returns a list of names that will be ignored, not copied.

The shutil module also provides an ignore_patterns() function for use with this new parameter. ignore_patterns() takes an arbitrary number of glob-style patterns and returns a callable that will ignore any files and directories that match any of these patterns. The following example copies a directory tree, but skips both .svn directories and Emacs backup files, which have names ending with ‘~’:

shutil.copytree('Doc/library', '/tmp/library',
                ignore=shutil.ignore_patterns('*~', '.svn'))

(Contributed by Tarek Ziadé; bpo-2663 [https://bugs.python.org/issue?@action=redirect&bpo=2663].)

Integrating signal handling with GUI handling event loops like those used by Tkinter or GTk+ has long been a problem; most software ends up polling, waking up every fraction of a second to check if any GUI events have occurred. The signal module can now make this more efficient. Calling signal.set_wakeup_fd(fd) sets a file descriptor to be used; when a signal is received, a byte is written to that file descriptor. There’s also a C-level function, PySignal_SetWakeupFd(), for setting the descriptor.

Event loops will use this by opening a pipe to create two descriptors, one for reading and one for writing. The writable descriptor will be passed to set_wakeup_fd(), and the readable descriptor will be added to the list of descriptors monitored by the event loop via select() or poll(). On receiving a signal, a byte will be written and the main event loop will be woken up, avoiding the need to poll.

(Contributed by Adam Olsen; bpo-1583 [https://bugs.python.org/issue?@action=redirect&bpo=1583].)

The siginterrupt() function is now available from Python code, and allows changing whether signals can interrupt system calls or not. (Contributed by Ralf Schmitt.)

The setitimer() and getitimer() functions have also been added (where they’re available). setitimer() allows setting interval timers that will cause a signal to be delivered to the process after a specified time, measured in wall-clock time, consumed process time, or combined process+system time. (Contributed by Guilherme Polo; bpo-2240 [https://bugs.python.org/issue?@action=redirect&bpo=2240].)

The smtplib module now supports SMTP over SSL thanks to the addition of the SMTP_SSL class. This class supports an interface identical to the existing SMTP class. (Contributed by Monty Taylor.) Both class constructors also have an optional timeout parameter that specifies a timeout for the initial connection attempt, measured in seconds. (Contributed by Facundo Batista.)

An implementation of the LMTP protocol (RFC 2033 [https://datatracker.ietf.org/doc/html/rfc2033.html]) was also added to the module. LMTP is used in place of SMTP when transferring e-mail between agents that don’t manage a mail queue. (LMTP implemented by Leif Hedstrom; bpo-957003 [https://bugs.python.org/issue?@action=redirect&bpo=957003].)

SMTP.starttls() now complies with RFC 3207 [https://datatracker.ietf.org/doc/html/rfc3207.html] and forgets any knowledge obtained from the server not obtained from the TLS negotiation itself. (Patch contributed by Bill Fenner; bpo-829951 [https://bugs.python.org/issue?@action=redirect&bpo=829951].)

The socket module now supports TIPC (https://tipc.sourceforge.net/), a high-performance non-IP-based protocol designed for use in clustered environments. TIPC addresses are 4- or 5-tuples. (Contributed by Alberto Bertogli; bpo-1646 [https://bugs.python.org/issue?@action=redirect&bpo=1646].)

A new function, create_connection(), takes an address and connects to it using an optional timeout value, returning the connected socket object. This function also looks up the address’s type and connects to it using IPv4 or IPv6 as appropriate. Changing your code to use create_connection() instead of socket(socket.AF_INET, ...) may be all that’s required to make your code work with IPv6.

The base classes in the SocketServer module now support calling a handle_timeout() method after a span of inactivity specified by the server’s timeout attribute. (Contributed by Michael Pomraning.) The serve_forever() method now takes an optional poll interval measured in seconds, controlling how often the server will check for a shutdown request. (Contributed by Pedro Werneck and Jeffrey Yasskin; bpo-742598 [https://bugs.python.org/issue?@action=redirect&bpo=742598], bpo-1193577 [https://bugs.python.org/issue?@action=redirect&bpo=1193577].)

The sqlite3 module, maintained by Gerhard Häring, has been updated from version 2.3.2 in Python 2.5 to version 2.4.1.

The struct module now supports the C99 _Bool type, using the format character '?'. (Contributed by David Remahl.)

The Popen objects provided by the subprocess module now have terminate(), kill(), and send_signal() methods. On Windows, send_signal() only supports the SIGTERM signal, and all these methods are aliases for the Win32 API function TerminateProcess(). (Contributed by Christian Heimes.)

A new variable in the sys module, float_info, is an object containing information derived from the float.h file about the platform’s floating-point support. Attributes of this object include mant_dig (number of digits in the mantissa), epsilon (smallest difference between 1.0 and the next largest value representable), and several others. (Contributed by Christian Heimes; bpo-1534 [https://bugs.python.org/issue?@action=redirect&bpo=1534].)

Another new variable, dont_write_bytecode, controls whether Python writes any .pyc or .pyo files on importing a module. If this variable is true, the compiled files are not written. The variable is initially set on start-up by supplying the -B switch to the Python interpreter, or by setting the PYTHONDONTWRITEBYTECODE environment variable before running the interpreter. Python code can subsequently change the value of this variable to control whether bytecode files are written or not. (Contributed by Neal Norwitz and Georg Brandl.)

Information about the command-line arguments supplied to the Python interpreter is available by reading attributes of a named tuple available as sys.flags. For example, the verbose attribute is true if Python was executed in verbose mode, debug is true in debugging mode, etc. These attributes are all read-only. (Contributed by Christian Heimes.)

A new function, getsizeof(), takes a Python object and returns the amount of memory used by the object, measured in bytes. Built-in objects return correct results; third-party extensions may not, but can define a __sizeof__() method to return the object’s size. (Contributed by Robert Schuppenies; bpo-2898 [https://bugs.python.org/issue?@action=redirect&bpo=2898].)

It’s now possible to determine the current profiler and tracer functions by calling sys.getprofile() and sys.gettrace(). (Contributed by Georg Brandl; bpo-1648 [https://bugs.python.org/issue?@action=redirect&bpo=1648].)

The tarfile module now supports POSIX.1-2001 (pax) tarfiles in addition to the POSIX.1-1988 (ustar) and GNU tar formats that were already supported. The default format is GNU tar; specify the format parameter to open a file using a different format:

tar = tarfile.open("output.tar", "w",
                   format=tarfile.PAX_FORMAT)

The new encoding and errors parameters specify an encoding and an error handling scheme for character conversions. 'strict', 'ignore', and 'replace' are the three standard ways Python can handle errors,; 'utf-8' is a special value that replaces bad characters with their UTF-8 representation. (Character conversions occur because the PAX format supports Unicode filenames, defaulting to UTF-8 encoding.)

The TarFile.add() method now accepts an exclude argument that’s a function that can be used to exclude certain filenames from an archive. The function must take a filename and return true if the file should be excluded or false if it should be archived. The function is applied to both the name initially passed to add() and to the names of files in recursively added directories.

(All changes contributed by Lars Gustäbel).

An optional timeout parameter was added to the telnetlib.Telnet class constructor, specifying a timeout measured in seconds. (Added by Facundo Batista.)

The tempfile.NamedTemporaryFile class usually deletes the temporary file it created when the file is closed. This behaviour can now be changed by passing delete=False to the constructor. (Contributed by Damien Miller; bpo-1537850 [https://bugs.python.org/issue?@action=redirect&bpo=1537850].)

A new class, SpooledTemporaryFile, behaves like a temporary file but stores its data in memory until a maximum size is exceeded. On reaching that limit, the contents will be written to an on-disk temporary file. (Contributed by Dustin J. Mitchell.)

The NamedTemporaryFile and SpooledTemporaryFile classes both work as context managers, so you can write with tempfile.NamedTemporaryFile() as tmp: .... (Contributed by Alexander Belopolsky; bpo-2021 [https://bugs.python.org/issue?@action=redirect&bpo=2021].)

The test.test_support module gained a number of context managers useful for writing tests. EnvironmentVarGuard() is a context manager that temporarily changes environment variables and automatically restores them to their old values.

Another context manager, TransientResource, can surround calls to resources that may or may not be available; it will catch and ignore a specified list of exceptions. For example, a network test may ignore certain failures when connecting to an external web site:

with test_support.TransientResource(IOError,
                                errno=errno.ETIMEDOUT):
    f = urllib.urlopen('https://sf.net')
    ...

Finally, check_warnings() resets the warning module’s warning filters and returns an object that will record all warning messages triggered (bpo-3781 [https://bugs.python.org/issue?@action=redirect&bpo=3781]):

with test_support.check_warnings() as wrec:
    warnings.simplefilter("always")
    # ... code that triggers a warning ...
    assert str(wrec.message) == "function is outdated"
    assert len(wrec.warnings) == 1, "Multiple warnings raised"

(Contributed by Brett Cannon.)

The textwrap module can now preserve existing whitespace at the beginnings and ends of the newly created lines by specifying drop_whitespace=False as an argument:

>>> S = """This  sentence  has a bunch   of
...   extra   whitespace."""
>>> print textwrap.fill(S, width=15)
This  sentence
has a bunch
of    extra
whitespace.
>>> print textwrap.fill(S, drop_whitespace=False, width=15)
This  sentence
  has a bunch
   of    extra
   whitespace.
>>>

(Contributed by Dwayne Bailey; bpo-1581073 [https://bugs.python.org/issue?@action=redirect&bpo=1581073].)

The threading module API is being changed to use properties such as daemon instead of setDaemon() and isDaemon() methods, and some methods have been renamed to use underscores instead of camel-case; for example, the activeCount() method is renamed to active_count(). Both the 2.6 and 3.0 versions of the module support the same properties and renamed methods, but don’t remove the old methods. No date has been set for the deprecation of the old APIs in Python 3.x; the old APIs won’t be removed in any 2.x version. (Carried out by several people, most notably Benjamin Peterson.)

The threading module’s Thread objects gained an ident property that returns the thread’s identifier, a nonzero integer. (Contributed by Gregory P. Smith; bpo-2871 [https://bugs.python.org/issue?@action=redirect&bpo=2871].)

The timeit module now accepts callables as well as strings for the statement being timed and for the setup code. Two convenience functions were added for creating Timer instances: repeat(stmt, setup, time, repeat, number) and timeit(stmt, setup, time, number) create an instance and call the corresponding method. (Contributed by Erik Demaine; bpo-1533909 [https://bugs.python.org/issue?@action=redirect&bpo=1533909].)

The Tkinter module now accepts lists and tuples for options, separating the elements by spaces before passing the resulting value to Tcl/Tk. (Contributed by Guilherme Polo; bpo-2906 [https://bugs.python.org/issue?@action=redirect&bpo=2906].)

The turtle module for turtle graphics was greatly enhanced by Gregor Lingl. New features in the module include:

Better animation of turtle movement and rotation.

Control over turtle movement using the new delay(), tracer(), and speed() methods.

The ability to set new shapes for the turtle, and to define a new coordinate system.

Turtles now have an undo() method that can roll back actions.

Simple support for reacting to input events such as mouse and keyboard activity, making it possible to write simple games.

A turtle.cfg file can be used to customize the starting appearance of the turtle’s screen.

The module’s docstrings can be replaced by new docstrings that have been translated into another language.

(bpo-1513695 [https://bugs.python.org/issue?@action=redirect&bpo=1513695])

An optional timeout parameter was added to the urllib.urlopen function and the urllib.ftpwrapper class constructor, as well as the urllib2.urlopen function. The parameter specifies a timeout measured in seconds. For example:

>>> u = urllib2.urlopen("http://slow.example.com",
                        timeout=3)
Traceback (most recent call last):
  ...
urllib2.URLError: <urlopen error timed out>
>>>

(Added by Facundo Batista.)

The Unicode database provided by the unicodedata module has been updated to version 5.1.0. (Updated by Martin von Löwis; bpo-3811 [https://bugs.python.org/issue?@action=redirect&bpo=3811].)

The warnings module’s formatwarning() and showwarning() gained an optional line argument that can be used to supply the line of source code. (Added as part of bpo-1631171 [https://bugs.python.org/issue?@action=redirect&bpo=1631171], which re-implemented part of the warnings module in C code.)

A new function, catch_warnings(), is a context manager intended for testing purposes that lets you temporarily modify the warning filters and then restore their original values (bpo-3781 [https://bugs.python.org/issue?@action=redirect&bpo=3781]).

The XML-RPC SimpleXMLRPCServer and DocXMLRPCServer classes can now be prevented from immediately opening and binding to their socket by passing False as the bind_and_activate constructor parameter. This can be used to modify the instance’s allow_reuse_address attribute before calling the server_bind() and server_activate() methods to open the socket and begin listening for connections. (Contributed by Peter Parente; bpo-1599845 [https://bugs.python.org/issue?@action=redirect&bpo=1599845].)

SimpleXMLRPCServer also has a _send_traceback_header attribute; if true, the exception and formatted traceback are returned as HTTP headers “X-Exception” and “X-Traceback”. This feature is for debugging purposes only and should not be used on production servers because the tracebacks might reveal passwords or other sensitive information. (Contributed by Alan McIntyre as part of his project for Google’s Summer of Code 2007.)

The xmlrpclib module no longer automatically converts datetime.date and datetime.time to the xmlrpclib.DateTime type; the conversion semantics were not necessarily correct for all applications. Code using xmlrpclib should convert date and time instances. (bpo-1330538 [https://bugs.python.org/issue?@action=redirect&bpo=1330538]) The code can also handle dates before 1900 (contributed by Ralf Schmitt; bpo-2014 [https://bugs.python.org/issue?@action=redirect&bpo=2014]) and 64-bit integers represented by using <i8> in XML-RPC responses (contributed by Riku Lindblad; bpo-2985 [https://bugs.python.org/issue?@action=redirect&bpo=2985]).

The zipfile module’s ZipFile class now has extract() and extractall() methods that will unpack a single file or all the files in the archive to the current directory, or to a specified directory:

z = zipfile.ZipFile('python-251.zip')

# Unpack a single file, writing it relative
# to the /tmp directory.
z.extract('Python/sysmodule.c', '/tmp')

# Unpack all the files in the archive.
z.extractall()

(Contributed by Alan McIntyre; bpo-467924 [https://bugs.python.org/issue?@action=redirect&bpo=467924].)

The open(), read() and extract() methods can now take either a filename or a ZipInfo object. This is useful when an archive accidentally contains a duplicated filename. (Contributed by Graham Horler; bpo-1775025 [https://bugs.python.org/issue?@action=redirect&bpo=1775025].)

Finally, zipfile now supports using Unicode filenames for archived files. (Contributed by Alexey Borzenkov; bpo-1734346 [https://bugs.python.org/issue?@action=redirect&bpo=1734346].)

The ast module

The ast module provides an Abstract Syntax Tree representation of Python code, and Armin Ronacher contributed a set of helper functions that perform a variety of common tasks. These will be useful for HTML templating packages, code analyzers, and similar tools that process Python code.

The parse() function takes an expression and returns an AST. The dump() function outputs a representation of a tree, suitable for debugging:

import ast

t = ast.parse("""
d = {}
for i in 'abcdefghijklm':
    d[i + i] = ord(i) - ord('a') + 1
print d
""")
print ast.dump(t)

This outputs a deeply nested tree:

Module(body=[
  Assign(targets=[
    Name(id='d', ctx=Store())
   ], value=Dict(keys=[], values=[]))
  For(target=Name(id='i', ctx=Store()),
      iter=Str(s='abcdefghijklm'), body=[
    Assign(targets=[
      Subscript(value=
        Name(id='d', ctx=Load()),
          slice=
          Index(value=
            BinOp(left=Name(id='i', ctx=Load()), op=Add(),
             right=Name(id='i', ctx=Load()))), ctx=Store())
     ], value=
     BinOp(left=
      BinOp(left=
       Call(func=
        Name(id='ord', ctx=Load()), args=[
          Name(id='i', ctx=Load())
         ], keywords=[], starargs=None, kwargs=None),
       op=Sub(), right=Call(func=
        Name(id='ord', ctx=Load()), args=[
          Str(s='a')
         ], keywords=[], starargs=None, kwargs=None)),
       op=Add(), right=Num(n=1)))
    ], orelse=[])
   Print(dest=None, values=[
     Name(id='d', ctx=Load())
   ], nl=True)
 ])

The literal_eval() method takes a string or an AST representing a literal expression, parses and evaluates it, and returns the resulting value. A literal expression is a Python expression containing only strings, numbers, dictionaries, etc. but no statements or function calls. If you need to evaluate an expression but cannot accept the security risk of using an eval() call, literal_eval() will handle it safely:

>>> literal = '("a", "b", {2:4, 3:8, 1:2})'
>>> print ast.literal_eval(literal)
('a', 'b', {1: 2, 2: 4, 3: 8})
>>> print ast.literal_eval('"a" + "b"')
Traceback (most recent call last):
  ...
ValueError: malformed string

The module also includes NodeVisitor and NodeTransformer classes for traversing and modifying an AST, and functions for common transformations such as changing line numbers.

The future_builtins module

Python 3.0 makes many changes to the repertoire of built-in functions, and most of the changes can’t be introduced in the Python 2.x series because they would break compatibility. The future_builtins module provides versions of these built-in functions that can be imported when writing 3.0-compatible code.

The functions in this module currently include:

ascii(obj): equivalent to repr(). In Python 3.0, repr() will return a Unicode string, while ascii() will return a pure ASCII bytestring.

filter(predicate, iterable), map(func, iterable1, ...): the 3.0 versions return iterators, unlike the 2.x builtins which return lists.

hex(value), oct(value): instead of calling the __hex__() or __oct__() methods, these versions will call the __index__() method and convert the result to hexadecimal or octal. oct() will use the new 0o notation for its result.

The json module: JavaScript Object Notation

The new json module supports the encoding and decoding of Python types in JSON (Javascript Object Notation). JSON is a lightweight interchange format often used in web applications. For more information about JSON, see http://www.json.org.

json comes with support for decoding and encoding most built-in Python types. The following example encodes and decodes a dictionary:

>>> import json
>>> data = {"spam": "foo", "parrot": 42}
>>> in_json = json.dumps(data) # Encode the data
>>> in_json
'{"parrot": 42, "spam": "foo"}'
>>> json.loads(in_json) # Decode into a Python object
{"spam": "foo", "parrot": 42}

It’s also possible to write your own decoders and encoders to support more types. Pretty-printing of the JSON strings is also supported.

json (originally called simplejson) was written by Bob Ippolito.

The plistlib module: A Property-List Parser

The .plist format is commonly used on Mac OS X to store basic data types (numbers, strings, lists, and dictionaries) by serializing them into an XML-based format. It resembles the XML-RPC serialization of data types.

Despite being primarily used on Mac OS X, the format has nothing Mac-specific about it and the Python implementation works on any platform that Python supports, so the plistlib module has been promoted to the standard library.

Using the module is simple:

import sys
import plistlib
import datetime

# Create data structure
data_struct = dict(lastAccessed=datetime.datetime.now(),
                   version=1,
                   categories=('Personal','Shared','Private'))

# Create string containing XML.
plist_str = plistlib.writePlistToString(data_struct)
new_struct = plistlib.readPlistFromString(plist_str)
print data_struct
print new_struct

# Write data structure to a file and read it back.
plistlib.writePlist(data_struct, '/tmp/customizations.plist')
new_struct = plistlib.readPlist('/tmp/customizations.plist')

# read/writePlist accepts file-like objects as well as paths.
plistlib.writePlist(data_struct, sys.stdout)

ctypes Enhancements

Thomas Heller continued to maintain and enhance the ctypes module.

ctypes now supports a c_bool datatype that represents the C99 bool type. (Contributed by David Remahl; bpo-1649190 [https://bugs.python.org/issue?@action=redirect&bpo=1649190].)

The ctypes string, buffer and array types have improved support for extended slicing syntax, where various combinations of (start, stop, step) are supplied. (Implemented by Thomas Wouters.)

All ctypes data types now support from_buffer() and from_buffer_copy() methods that create a ctypes instance based on a provided buffer object. from_buffer_copy() copies the contents of the object, while from_buffer() will share the same memory area.

A new calling convention tells ctypes to clear the errno or Win32 LastError variables at the outset of each wrapped call. (Implemented by Thomas Heller; bpo-1798 [https://bugs.python.org/issue?@action=redirect&bpo=1798].)

You can now retrieve the Unix errno variable after a function call. When creating a wrapped function, you can supply use_errno=True as a keyword parameter to the DLL() function and then call the module-level methods set_errno() and get_errno() to set and retrieve the error value.

The Win32 LastError variable is similarly supported by the DLL(), OleDLL(), and WinDLL() functions. You supply use_last_error=True as a keyword parameter and then call the module-level methods set_last_error() and get_last_error().

The byref() function, used to retrieve a pointer to a ctypes instance, now has an optional offset parameter that is a byte count that will be added to the returned pointer.

Improved SSL Support

Bill Janssen made extensive improvements to Python 2.6’s support for the Secure Sockets Layer by adding a new module, ssl, that’s built atop the OpenSSL [https://www.openssl.org/] library. This new module provides more control over the protocol negotiated, the X.509 certificates used, and has better support for writing SSL servers (as opposed to clients) in Python. The existing SSL support in the socket module hasn’t been removed and continues to work, though it will be removed in Python 3.0.

To use the new module, you must first create a TCP connection in the usual way and then pass it to the ssl.wrap_socket() function. It’s possible to specify whether a certificate is required, and to obtain certificate info by calling the getpeercert() method.

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The documentation for the ssl module.

Deprecations and Removals

String exceptions have been removed. Attempting to use them raises a TypeError.

Changes to the Exception interface as dictated by PEP 352 [https://peps.python.org/pep-0352/] continue to be made. For 2.6, the message attribute is being deprecated in favor of the args attribute.

(3.0-warning mode) Python 3.0 will feature a reorganized standard library that will drop many outdated modules and rename others. Python 2.6 running in 3.0-warning mode will warn about these modules when they are imported.

The list of deprecated modules is: audiodev, bgenlocations, buildtools, bundlebuilder, Canvas, compiler, dircache, dl, fpformat, gensuitemodule, ihooks, imageop, imgfile, linuxaudiodev, mhlib, mimetools, multifile, new, pure, statvfs, sunaudiodev, test.testall, and toaiff.

The gopherlib module has been removed.

The MimeWriter module and mimify module have been deprecated; use the email package instead.

The md5 module has been deprecated; use the hashlib module instead.

The posixfile module has been deprecated; fcntl.lockf() provides better locking.

The popen2 module has been deprecated; use the subprocess module.

The rgbimg module has been removed.

The sets module has been deprecated; it’s better to use the built-in set and frozenset types.

The sha module has been deprecated; use the hashlib module instead.

Build and C API Changes

Changes to Python’s build process and to the C API include:

Python now must be compiled with C89 compilers (after 19 years!). This means that the Python source tree has dropped its own implementations of memmove() and strerror(), which are in the C89 standard library.

Python 2.6 can be built with Microsoft Visual Studio 2008 (version 9.0), and this is the new default compiler. See the PCbuild directory for the build files. (Implemented by Christian Heimes.)

On Mac OS X, Python 2.6 can be compiled as a 4-way universal build. The configure script can take a --with-universal-archs=[32-bit|64-bit|all] switch, controlling whether the binaries are built for 32-bit architectures (x86, PowerPC), 64-bit (x86-64 and PPC-64), or both. (Contributed by Ronald Oussoren.)

A new function added in Python 2.6.6, PySys_SetArgvEx(), sets the value of sys.argv and can optionally update sys.path to include the directory containing the script named by sys.argv[0] depending on the value of an updatepath parameter.

This function was added to close a security hole for applications that embed Python. The old function, PySys_SetArgv(), would always update sys.path, and sometimes it would add the current directory. This meant that, if you ran an application embedding Python in a directory controlled by someone else, attackers could put a Trojan-horse module in the directory (say, a file named os.py) that your application would then import and run.

If you maintain a C/C++ application that embeds Python, check whether you’re calling PySys_SetArgv() and carefully consider whether the application should be using PySys_SetArgvEx() with updatepath set to false. Note that using this function will break compatibility with Python versions 2.6.5 and earlier; if you have to continue working with earlier versions, you can leave the call to PySys_SetArgv() alone and call PyRun_SimpleString("sys.path.pop(0)\n") afterwards to discard the first sys.path component.

Security issue reported as CVE 2008-5983 [https://www.cve.org/CVERecord?id=CVE-2008-5983]; discussed in gh-50003 [https://github.com/python/cpython/issues/50003], and fixed by Antoine Pitrou.

The BerkeleyDB module now has a C API object, available as bsddb.db.api. This object can be used by other C extensions that wish to use the bsddb module for their own purposes. (Contributed by Duncan Grisby.)

The new buffer interface, previously described in the PEP 3118 section, adds PyObject_GetBuffer() and PyBuffer_Release(), as well as a few other functions.

Python’s use of the C stdio library is now thread-safe, or at least as thread-safe as the underlying library is. A long-standing potential bug occurred if one thread closed a file object while another thread was reading from or writing to the object. In 2.6 file objects have a reference count, manipulated by the PyFile_IncUseCount() and PyFile_DecUseCount() functions. File objects can’t be closed unless the reference count is zero. PyFile_IncUseCount() should be called while the GIL is still held, before carrying out an I/O operation using the FILE * pointer, and PyFile_DecUseCount() should be called immediately after the GIL is re-acquired. (Contributed by Antoine Pitrou and Gregory P. Smith.)

Importing modules simultaneously in two different threads no longer deadlocks; it will now raise an ImportError. A new API function, PyImport_ImportModuleNoBlock(), will look for a module in sys.modules first, then try to import it after acquiring an import lock. If the import lock is held by another thread, an ImportError is raised. (Contributed by Christian Heimes.)

Several functions return information about the platform’s floating-point support. PyFloat_GetMax() returns the maximum representable floating-point value, and PyFloat_GetMin() returns the minimum positive value. PyFloat_GetInfo() returns an object containing more information from the float.h file, such as "mant_dig" (number of digits in the mantissa), "epsilon" (smallest difference between 1.0 and the next largest value representable), and several others. (Contributed by Christian Heimes; bpo-1534 [https://bugs.python.org/issue?@action=redirect&bpo=1534].)

C functions and methods that use PyComplex_AsCComplex() will now accept arguments that have a __complex__() method. In particular, the functions in the cmath module will now accept objects with this method. This is a backport of a Python 3.0 change. (Contributed by Mark Dickinson; bpo-1675423 [https://bugs.python.org/issue?@action=redirect&bpo=1675423].)

Python’s C API now includes two functions for case-insensitive string comparisons, PyOS_stricmp(char*, char*) and PyOS_strnicmp(char*, char*, Py_ssize_t). (Contributed by Christian Heimes; bpo-1635 [https://bugs.python.org/issue?@action=redirect&bpo=1635].)

Many C extensions define their own little macro for adding integers and strings to the module’s dictionary in the init* function. Python 2.6 finally defines standard macros for adding values to a module, PyModule_AddStringMacro and PyModule_AddIntMacro(). (Contributed by Christian Heimes.)

Some macros were renamed in both 3.0 and 2.6 to make it clearer that they are macros, not functions. Py_Size() became Py_SIZE(), Py_Type() became Py_TYPE(), and Py_Refcnt() became Py_REFCNT(). The mixed-case macros are still available in Python 2.6 for backward compatibility. (bpo-1629 [https://bugs.python.org/issue?@action=redirect&bpo=1629])

Distutils now places C extensions it builds in a different directory when running on a debug version of Python. (Contributed by Collin Winter; bpo-1530959 [https://bugs.python.org/issue?@action=redirect&bpo=1530959].)

Several basic data types, such as integers and strings, maintain internal free lists of objects that can be re-used. The data structures for these free lists now follow a naming convention: the variable is always named free_list, the counter is always named numfree, and a macro Py<typename>_MAXFREELIST is always defined.

A new Makefile target, “make patchcheck”, prepares the Python source tree for making a patch: it fixes trailing whitespace in all modified .py files, checks whether the documentation has been changed, and reports whether the Misc/ACKS and Misc/NEWS files have been updated. (Contributed by Brett Cannon.)

Another new target, “make profile-opt”, compiles a Python binary using GCC’s profile-guided optimization. It compiles Python with profiling enabled, runs the test suite to obtain a set of profiling results, and then compiles using these results for optimization. (Contributed by Gregory P. Smith.)

Port-Specific Changes: Windows

The support for Windows 95, 98, ME and NT4 has been dropped. Python 2.6 requires at least Windows 2000 SP4.

The new default compiler on Windows is Visual Studio 2008 (version 9.0). The build directories for Visual Studio 2003 (version 7.1) and 2005 (version 8.0) were moved into the PC/ directory. The new PCbuild directory supports cross compilation for X64, debug builds and Profile Guided Optimization (PGO). PGO builds are roughly 10% faster than normal builds. (Contributed by Christian Heimes with help from Amaury Forgeot d’Arc and Martin von Löwis.)

The msvcrt module now supports both the normal and wide char variants of the console I/O API. The getwch() function reads a keypress and returns a Unicode value, as does the getwche() function. The putwch() function takes a Unicode character and writes it to the console. (Contributed by Christian Heimes.)

os.path.expandvars() will now expand environment variables in the form “%var%”, and “~user” will be expanded into the user’s home directory path. (Contributed by Josiah Carlson; bpo-957650 [https://bugs.python.org/issue?@action=redirect&bpo=957650].)

The socket module’s socket objects now have an ioctl() method that provides a limited interface to the WSAIoctl() system interface.

The _winreg module now has a function, ExpandEnvironmentStrings(), that expands environment variable references such as %NAME% in an input string. The handle objects provided by this module now support the context protocol, so they can be used in with statements. (Contributed by Christian Heimes.)

_winreg also has better support for x64 systems, exposing the DisableReflectionKey(), EnableReflectionKey(), and QueryReflectionKey() functions, which enable and disable registry reflection for 32-bit processes running on 64-bit systems. (bpo-1753245 [https://bugs.python.org/issue?@action=redirect&bpo=1753245])

The msilib module’s Record object gained GetInteger() and GetString() methods that return field values as an integer or a string. (Contributed by Floris Bruynooghe; bpo-2125 [https://bugs.python.org/issue?@action=redirect&bpo=2125].)

Port-Specific Changes: Mac OS X

When compiling a framework build of Python, you can now specify the framework name to be used by providing the --with-framework-name= option to the configure script.

The macfs module has been removed. This in turn required the macostools.touched() function to be removed because it depended on the macfs module. (bpo-1490190 [https://bugs.python.org/issue?@action=redirect&bpo=1490190])

Many other Mac OS modules have been deprecated and will be removed in Python 3.0: _builtinSuites, aepack, aetools, aetypes, applesingle, appletrawmain, appletrunner, argvemulator, Audio_mac, autoGIL, Carbon, cfmfile, CodeWarrior, ColorPicker, EasyDialogs, Explorer, Finder, FrameWork, findertools, ic, icglue, icopen, macerrors, MacOS, macfs, macostools, macresource, MiniAEFrame, Nav, Netscape, OSATerminology, pimp, PixMapWrapper, StdSuites, SystemEvents, Terminal, and terminalcommand.

Port-Specific Changes: IRIX

A number of old IRIX-specific modules were deprecated and will be removed in Python 3.0: al and AL, cd, cddb, cdplayer, CL and cl, DEVICE, ERRNO, FILE, FL and fl, flp, fm, GET, GLWS, GL and gl, IN, IOCTL, jpeg, panelparser, readcd, SV and sv, torgb, videoreader, and WAIT.

Porting to Python 2.6

This section lists previously described changes and other bugfixes that may require changes to your code:

Classes that aren’t supposed to be hashable should set __hash__ = None in their definitions to indicate the fact.

String exceptions have been removed. Attempting to use them raises a TypeError.

The __init__() method of collections.deque now clears any existing contents of the deque before adding elements from the iterable. This change makes the behavior match list.__init__().

object.__init__() previously accepted arbitrary arguments and keyword arguments, ignoring them. In Python 2.6, this is no longer allowed and will result in a TypeError. This will affect __init__() methods that end up calling the corresponding method on object (perhaps through using super()). See bpo-1683368 [https://bugs.python.org/issue?@action=redirect&bpo=1683368] for discussion.

The Decimal constructor now accepts leading and trailing whitespace when passed a string. Previously it would raise an InvalidOperation exception. On the other hand, the create_decimal() method of Context objects now explicitly disallows extra whitespace, raising a ConversionSyntax exception.

Due to an implementation accident, if you passed a file path to the built-in __import__() function, it would actually import the specified file. This was never intended to work, however, and the implementation now explicitly checks for this case and raises an ImportError.

C API: the PyImport_Import() and PyImport_ImportModule() functions now default to absolute imports, not relative imports. This will affect C extensions that import other modules.

C API: extension data types that shouldn’t be hashable should define their tp_hash slot to PyObject_HashNotImplemented().

The socket module exception socket.error now inherits from IOError. Previously it wasn’t a subclass of StandardError but now it is, through IOError. (Implemented by Gregory P. Smith; bpo-1706815 [https://bugs.python.org/issue?@action=redirect&bpo=1706815].)

The xmlrpclib module no longer automatically converts datetime.date and datetime.time to the xmlrpclib.DateTime type; the conversion semantics were not necessarily correct for all applications. Code using xmlrpclib should convert date and time instances. (bpo-1330538 [https://bugs.python.org/issue?@action=redirect&bpo=1330538])

(3.0-warning mode) The Exception class now warns when accessed using slicing or index access; having Exception behave like a tuple is being phased out.

(3.0-warning mode) inequality comparisons between two dictionaries or two objects that don’t implement comparison methods are reported as warnings. dict1 == dict2 still works, but dict1 < dict2 is being phased out.

Comparisons between cells, which are an implementation detail of Python’s scoping rules, also cause warnings because such comparisons are forbidden entirely in 3.0.

For applications that embed Python:

The PySys_SetArgvEx() function was added in Python 2.6.6, letting applications close a security hole when the existing PySys_SetArgv() function was used. Check whether you’re calling PySys_SetArgv() and carefully consider whether the application should be using PySys_SetArgvEx() with updatepath set to false.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Georg Brandl, Steve Brown, Nick Coghlan, Ralph Corderoy, Jim Jewett, Kent Johnson, Chris Lambacher, Martin Michlmayr, Antoine Pitrou, Brian Warner.

What’s New in Python 2.5

Author:

A.M. Kuchling

This article explains the new features in Python 2.5. The final release of Python 2.5 is scheduled for August 2006; PEP 356 [https://peps.python.org/pep-0356/] describes the planned release schedule. Python 2.5 was released on September 19, 2006.

The changes in Python 2.5 are an interesting mix of language and library improvements. The library enhancements will be more important to Python’s user community, I think, because several widely useful packages were added. New modules include ElementTree for XML processing (xml.etree), the SQLite database module (sqlite), and the ctypes module for calling C functions.

The language changes are of middling significance. Some pleasant new features were added, but most of them aren’t features that you’ll use every day. Conditional expressions were finally added to the language using a novel syntax; see section PEP 308: Conditional Expressions. The new ‘with’ statement will make writing cleanup code easier (section PEP 343: The ‘with’ statement). Values can now be passed into generators (section PEP 342: New Generator Features). Imports are now visible as either absolute or relative (section PEP 328: Absolute and Relative Imports). Some corner cases of exception handling are handled better (section PEP 341: Unified try/except/finally). All these improvements are worthwhile, but they’re improvements to one specific language feature or another; none of them are broad modifications to Python’s semantics.

As well as the language and library additions, other improvements and bugfixes were made throughout the source tree. A search through the SVN change logs finds there were 353 patches applied and 458 bugs fixed between Python 2.4 and 2.5. (Both figures are likely to be underestimates.)

This article doesn’t try to be a complete specification of the new features; instead changes are briefly introduced using helpful examples. For full details, you should always refer to the documentation for Python 2.5 at https://docs.python.org. If you want to understand the complete implementation and design rationale, refer to the PEP for a particular new feature.

Comments, suggestions, and error reports for this document are welcome; please e-mail them to the author or open a bug in the Python bug tracker.

PEP 308: Conditional Expressions

For a long time, people have been requesting a way to write conditional expressions, which are expressions that return value A or value B depending on whether a Boolean value is true or false. A conditional expression lets you write a single assignment statement that has the same effect as the following:

if condition:
    x = true_value
else:
    x = false_value

There have been endless tedious discussions of syntax on both python-dev and comp.lang.python. A vote was even held that found the majority of voters wanted conditional expressions in some form, but there was no syntax that was preferred by a clear majority. Candidates included C’s cond ? true_v : false_v, if cond then true_v else false_v, and 16 other variations.

Guido van Rossum eventually chose a surprising syntax:

x = true_value if condition else false_value

Evaluation is still lazy as in existing Boolean expressions, so the order of evaluation jumps around a bit. The condition expression in the middle is evaluated first, and the true_value expression is evaluated only if the condition was true. Similarly, the false_value expression is only evaluated when the condition is false.

This syntax may seem strange and backwards; why does the condition go in the middle of the expression, and not in the front as in C’s c ? x : y? The decision was checked by applying the new syntax to the modules in the standard library and seeing how the resulting code read. In many cases where a conditional expression is used, one value seems to be the ‘common case’ and one value is an ‘exceptional case’, used only on rarer occasions when the condition isn’t met. The conditional syntax makes this pattern a bit more obvious:

contents = ((doc + '\n') if doc else '')

I read the above statement as meaning “here contents is usually assigned a value of doc+'\n'; sometimes doc is empty, in which special case an empty string is returned.” I doubt I will use conditional expressions very often where there isn’t a clear common and uncommon case.

There was some discussion of whether the language should require surrounding conditional expressions with parentheses. The decision was made to not require parentheses in the Python language’s grammar, but as a matter of style I think you should always use them. Consider these two statements:

# First version -- no parens
level = 1 if logging else 0

# Second version -- with parens
level = (1 if logging else 0)

In the first version, I think a reader’s eye might group the statement into ‘level = 1’, ‘if logging’, ‘else 0’, and think that the condition decides whether the assignment to level is performed. The second version reads better, in my opinion, because it makes it clear that the assignment is always performed and the choice is being made between two values.

Another reason for including the brackets: a few odd combinations of list comprehensions and lambdas could look like incorrect conditional expressions. See PEP 308 [https://peps.python.org/pep-0308/] for some examples. If you put parentheses around your conditional expressions, you won’t run into this case.

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PEP 308 [https://peps.python.org/pep-0308/] - Conditional Expressions

PEP written by Guido van Rossum and Raymond D. Hettinger; implemented by Thomas Wouters.

PEP 309: Partial Function Application

The functools module is intended to contain tools for functional-style programming.

One useful tool in this module is the partial() function. For programs written in a functional style, you’ll sometimes want to construct variants of existing functions that have some of the parameters filled in. Consider a Python function f(a, b, c); you could create a new function g(b, c) that was equivalent to f(1, b, c). This is called “partial function application”.

partial() takes the arguments (function, arg1, arg2, ... kwarg1=value1, kwarg2=value2). The resulting object is callable, so you can just call it to invoke function with the filled-in arguments.

Here’s a small but realistic example:

import functools

def log (message, subsystem):
    "Write the contents of 'message' to the specified subsystem."
    print '%s: %s' % (subsystem, message)
    ...

server_log = functools.partial(log, subsystem='server')
server_log('Unable to open socket')

Here’s another example, from a program that uses PyGTK. Here a context-sensitive pop-up menu is being constructed dynamically. The callback provided for the menu option is a partially applied version of the open_item() method, where the first argument has been provided.

...
class Application:
    def open_item(self, path):
       ...
    def init (self):
        open_func = functools.partial(self.open_item, item_path)
        popup_menu.append( ("Open", open_func, 1) )

Another function in the functools module is the update_wrapper(wrapper, wrapped) function that helps you write well-behaved decorators. update_wrapper() copies the name, module, and docstring attribute to a wrapper function so that tracebacks inside the wrapped function are easier to understand. For example, you might write:

def my_decorator(f):
    def wrapper(*args, **kwds):
        print 'Calling decorated function'
        return f(*args, **kwds)
    functools.update_wrapper(wrapper, f)
    return wrapper

wraps() is a decorator that can be used inside your own decorators to copy the wrapped function’s information. An alternate version of the previous example would be:

def my_decorator(f):
    @functools.wraps(f)
    def wrapper(*args, **kwds):
        print 'Calling decorated function'
        return f(*args, **kwds)
    return wrapper

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PEP 309 [https://peps.python.org/pep-0309/] - Partial Function Application

PEP proposed and written by Peter Harris; implemented by Hye-Shik Chang and Nick Coghlan, with adaptations by Raymond Hettinger.

PEP 314: Metadata for Python Software Packages v1.1

Some simple dependency support was added to Distutils. The setup() function now has requires, provides, and obsoletes keyword parameters. When you build a source distribution using the sdist command, the dependency information will be recorded in the PKG-INFO file.

Another new keyword parameter is download_url, which should be set to a URL for the package’s source code. This means it’s now possible to look up an entry in the package index, determine the dependencies for a package, and download the required packages.

VERSION = '1.0'
setup(name='PyPackage',
      version=VERSION,
      requires=['numarray', 'zlib (>=1.1.4)'],
      obsoletes=['OldPackage']
      download_url=('http://www.example.com/pypackage/dist/pkg-%s.tar.gz'
                    % VERSION),
     )

Another new enhancement to the Python package index at https://pypi.org is storing source and binary archives for a package. The new upload Distutils command will upload a package to the repository.

Before a package can be uploaded, you must be able to build a distribution using the sdist Distutils command. Once that works, you can run python setup.py upload to add your package to the PyPI archive. Optionally you can GPG-sign the package by supplying the --sign and --identity options.

Package uploading was implemented by Martin von Löwis and Richard Jones.

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PEP 314 [https://peps.python.org/pep-0314/] - Metadata for Python Software Packages v1.1

PEP proposed and written by A.M. Kuchling, Richard Jones, and Fred Drake; implemented by Richard Jones and Fred Drake.

PEP 328: Absolute and Relative Imports

The simpler part of PEP 328 [https://peps.python.org/pep-0328/] was implemented in Python 2.4: parentheses could now be used to enclose the names imported from a module using the from ... import ... statement, making it easier to import many different names.

The more complicated part has been implemented in Python 2.5: importing a module can be specified to use absolute or package-relative imports. The plan is to move toward making absolute imports the default in future versions of Python.

Let’s say you have a package directory like this:

pkg/
pkg/__init__.py
pkg/main.py
pkg/string.py

This defines a package named pkg containing the pkg.main and pkg.string submodules.

Consider the code in the main.py module. What happens if it executes the statement import string? In Python 2.4 and earlier, it will first look in the package’s directory to perform a relative import, finds pkg/string.py, imports the contents of that file as the pkg.string module, and that module is bound to the name string in the pkg.main module’s namespace.

That’s fine if pkg.string was what you wanted. But what if you wanted Python’s standard string module? There’s no clean way to ignore pkg.string and look for the standard module; generally you had to look at the contents of sys.modules, which is slightly unclean. Holger Krekel’s py.std package provides a tidier way to perform imports from the standard library, import py; py.std.string.join(), but that package isn’t available on all Python installations.

Reading code which relies on relative imports is also less clear, because a reader may be confused about which module, string or pkg.string, is intended to be used. Python users soon learned not to duplicate the names of standard library modules in the names of their packages’ submodules, but you can’t protect against having your submodule’s name being used for a new module added in a future version of Python.

In Python 2.5, you can switch import’s behaviour to absolute imports using a from __future__ import absolute_import directive. This absolute-import behaviour will become the default in a future version (probably Python 2.7). Once absolute imports are the default, import string will always find the standard library’s version. It’s suggested that users should begin using absolute imports as much as possible, so it’s preferable to begin writing from pkg import string in your code.

Relative imports are still possible by adding a leading period to the module name when using the from ... import form:

# Import names from pkg.string
from .string import name1, name2
# Import pkg.string
from . import string

This imports the string module relative to the current package, so in pkg.main this will import name1 and name2 from pkg.string. Additional leading periods perform the relative import starting from the parent of the current package. For example, code in the A.B.C module can do:

from . import D                 # Imports A.B.D
from .. import E                # Imports A.E
from ..F import G               # Imports A.F.G

Leading periods cannot be used with the import modname form of the import statement, only the from ... import form.

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PEP 328 [https://peps.python.org/pep-0328/] - Imports: Multi-Line and Absolute/Relative

PEP written by Aahz; implemented by Thomas Wouters.

https://pylib.readthedocs.io/

The py library by Holger Krekel, which contains the py.std package.

PEP 338: Executing Modules as Scripts

The -m switch added in Python 2.4 to execute a module as a script gained a few more abilities. Instead of being implemented in C code inside the Python interpreter, the switch now uses an implementation in a new module, runpy.

The runpy module implements a more sophisticated import mechanism so that it’s now possible to run modules in a package such as pychecker.checker. The module also supports alternative import mechanisms such as the zipimport module. This means you can add a .zip archive’s path to sys.path and then use the -m switch to execute code from the archive.

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PEP 338 [https://peps.python.org/pep-0338/] - Executing modules as scripts

PEP written and implemented by Nick Coghlan.

PEP 341: Unified try/except/finally

Until Python 2.5, the try statement came in two flavours. You could use a finally block to ensure that code is always executed, or one or more except blocks to catch specific exceptions. You couldn’t combine both except blocks and a finally block, because generating the right bytecode for the combined version was complicated and it wasn’t clear what the semantics of the combined statement should be.

Guido van Rossum spent some time working with Java, which does support the equivalent of combining except blocks and a finally block, and this clarified what the statement should mean. In Python 2.5, you can now write:

try:
    block-1 ...
except Exception1:
    handler-1 ...
except Exception2:
    handler-2 ...
else:
    else-block
finally:
    final-block

The code in block-1 is executed. If the code raises an exception, the various except blocks are tested: if the exception is of class Exception1, handler-1 is executed; otherwise if it’s of class Exception2, handler-2 is executed, and so forth. If no exception is raised, the else-block is executed.

No matter what happened previously, the final-block is executed once the code block is complete and any raised exceptions handled. Even if there’s an error in an exception handler or the else-block and a new exception is raised, the code in the final-block is still run.

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PEP 341 [https://peps.python.org/pep-0341/] - Unifying try-except and try-finally

PEP written by Georg Brandl; implementation by Thomas Lee.

PEP 342: New Generator Features

Python 2.5 adds a simple way to pass values into a generator. As introduced in Python 2.3, generators only produce output; once a generator’s code was invoked to create an iterator, there was no way to pass any new information into the function when its execution is resumed. Sometimes the ability to pass in some information would be useful. Hackish solutions to this include making the generator’s code look at a global variable and then changing the global variable’s value, or passing in some mutable object that callers then modify.

To refresh your memory of basic generators, here’s a simple example:

def counter (maximum):
    i = 0
    while i < maximum:
        yield i
        i += 1

When you call counter(10), the result is an iterator that returns the values from 0 up to 9. On encountering the yield statement, the iterator returns the provided value and suspends the function’s execution, preserving the local variables. Execution resumes on the following call to the iterator’s next() method, picking up after the yield statement.

In Python 2.3, yield was a statement; it didn’t return any value. In 2.5, yield is now an expression, returning a value that can be assigned to a variable or otherwise operated on:

val = (yield i)

I recommend that you always put parentheses around a yield expression when you’re doing something with the returned value, as in the above example. The parentheses aren’t always necessary, but it’s easier to always add them instead of having to remember when they’re needed.

(PEP 342 [https://peps.python.org/pep-0342/] explains the exact rules, which are that a yield-expression must always be parenthesized except when it occurs at the top-level expression on the right-hand side of an assignment. This means you can write val = yield i but have to use parentheses when there’s an operation, as in val = (yield i) + 12.)

Values are sent into a generator by calling its send(value) method. The generator’s code is then resumed and the yield expression returns the specified value. If the regular next() method is called, the yield returns None.

Here’s the previous example, modified to allow changing the value of the internal counter.

def counter (maximum):
    i = 0
    while i < maximum:
        val = (yield i)
        # If value provided, change counter
        if val is not None:
            i = val
        else:
            i += 1

And here’s an example of changing the counter:

>>> it = counter(10)
>>> print it.next()
0
>>> print it.next()
1
>>> print it.send(8)
8
>>> print it.next()
9
>>> print it.next()
Traceback (most recent call last):
  File "t.py", line 15, in ?
    print it.next()
StopIteration

yield will usually return None, so you should always check for this case. Don’t just use its value in expressions unless you’re sure that the send() method will be the only method used to resume your generator function.

In addition to send(), there are two other new methods on generators:

throw(type, value=None, traceback=None) is used to raise an exception inside the generator; the exception is raised by the yield expression where the generator’s execution is paused.

close() raises a new GeneratorExit exception inside the generator to terminate the iteration. On receiving this exception, the generator’s code must either raise GeneratorExit or StopIteration. Catching the GeneratorExit exception and returning a value is illegal and will trigger a RuntimeError; if the function raises some other exception, that exception is propagated to the caller. close() will also be called by Python’s garbage collector when the generator is garbage-collected.

If you need to run cleanup code when a GeneratorExit occurs, I suggest using a try: ... finally: suite instead of catching GeneratorExit.

The cumulative effect of these changes is to turn generators from one-way producers of information into both producers and consumers.

Generators also become coroutines, a more generalized form of subroutines. Subroutines are entered at one point and exited at another point (the top of the function, and a return statement), but coroutines can be entered, exited, and resumed at many different points (the yield statements). We’ll have to figure out patterns for using coroutines effectively in Python.

The addition of the close() method has one side effect that isn’t obvious. close() is called when a generator is garbage-collected, so this means the generator’s code gets one last chance to run before the generator is destroyed. This last chance means that try...finally statements in generators can now be guaranteed to work; the finally clause will now always get a chance to run. The syntactic restriction that you couldn’t mix yield statements with a try...finally suite has therefore been removed. This seems like a minor bit of language trivia, but using generators and try...finally is actually necessary in order to implement the with statement described by PEP 343 [https://peps.python.org/pep-0343/]. I’ll look at this new statement in the following section.

Another even more esoteric effect of this change: previously, the gi_frame attribute of a generator was always a frame object. It’s now possible for gi_frame to be None once the generator has been exhausted.

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PEP 342 [https://peps.python.org/pep-0342/] - Coroutines via Enhanced Generators

PEP written by Guido van Rossum and Phillip J. Eby; implemented by Phillip J. Eby. Includes examples of some fancier uses of generators as coroutines.

Earlier versions of these features were proposed in PEP 288 [https://peps.python.org/pep-0288/] by Raymond Hettinger and PEP 325 [https://peps.python.org/pep-0325/] by Samuele Pedroni.

https://en.wikipedia.org/wiki/Coroutine

The Wikipedia entry for coroutines.

https://web.archive.org/web/20160321211320/http://www.sidhe.org/~dan/blog/archives/000178.html

An explanation of coroutines from a Perl point of view, written by Dan Sugalski.

PEP 343: The ‘with’ statement

The ‘with’ statement clarifies code that previously would use try...finally blocks to ensure that clean-up code is executed. In this section, I’ll discuss the statement as it will commonly be used. In the next section, I’ll examine the implementation details and show how to write objects for use with this statement.

The ‘with’ statement is a new control-flow structure whose basic structure is:

with expression [as variable]:
    with-block

The expression is evaluated, and it should result in an object that supports the context management protocol (that is, has __enter__() and __exit__() methods.

The object’s __enter__() is called before with-block is executed and therefore can run set-up code. It also may return a value that is bound to the name variable, if given. (Note carefully that variable is not assigned the result of expression.)

After execution of the with-block is finished, the object’s __exit__() method is called, even if the block raised an exception, and can therefore run clean-up code.

To enable the statement in Python 2.5, you need to add the following directive to your module:

from __future__ import with_statement

The statement will always be enabled in Python 2.6.

Some standard Python objects now support the context management protocol and can be used with the ‘with’ statement. File objects are one example:

with open('/etc/passwd', 'r') as f:
    for line in f:
        print line
        ... more processing code ...

After this statement has executed, the file object in f will have been automatically closed, even if the for loop raised an exception part-way through the block.

참고

In this case, f is the same object created by open(), because __enter__() returns self.

The threading module’s locks and condition variables also support the ‘with’ statement:

lock = threading.Lock()
with lock:
    # Critical section of code
    ...

The lock is acquired before the block is executed and always released once the block is complete.

The new localcontext() function in the decimal module makes it easy to save and restore the current decimal context, which encapsulates the desired precision and rounding characteristics for computations:

from decimal import Decimal, Context, localcontext

# Displays with default precision of 28 digits
v = Decimal('578')
print v.sqrt()

with localcontext(Context(prec=16)):
    # All code in this block uses a precision of 16 digits.
    # The original context is restored on exiting the block.
    print v.sqrt()

Writing Context Managers

Under the hood, the ‘with’ statement is fairly complicated. Most people will only use ‘with’ in company with existing objects and don’t need to know these details, so you can skip the rest of this section if you like. Authors of new objects will need to understand the details of the underlying implementation and should keep reading.

A high-level explanation of the context management protocol is:

The expression is evaluated and should result in an object called a “context manager”. The context manager must have __enter__() and __exit__() methods.

The context manager’s __enter__() method is called. The value returned is assigned to VAR. If no 'as VAR' clause is present, the value is simply discarded.

The code in BLOCK is executed.

If BLOCK raises an exception, the __exit__(type, value, traceback) is called with the exception details, the same values returned by sys.exc_info(). The method’s return value controls whether the exception is re-raised: any false value re-raises the exception, and True will result in suppressing it. You’ll only rarely want to suppress the exception, because if you do the author of the code containing the ‘with’ statement will never realize anything went wrong.

If BLOCK didn’t raise an exception, the __exit__() method is still called, but type, value, and traceback are all None.

Let’s think through an example. I won’t present detailed code but will only sketch the methods necessary for a database that supports transactions.

(For people unfamiliar with database terminology: a set of changes to the database are grouped into a transaction. Transactions can be either committed, meaning that all the changes are written into the database, or rolled back, meaning that the changes are all discarded and the database is unchanged. See any database textbook for more information.)

Let’s assume there’s an object representing a database connection. Our goal will be to let the user write code like this:

db_connection = DatabaseConnection()
with db_connection as cursor:
    cursor.execute('insert into ...')
    cursor.execute('delete from ...')
    # ... more operations ...

The transaction should be committed if the code in the block runs flawlessly or rolled back if there’s an exception. Here’s the basic interface for DatabaseConnection that I’ll assume:

class DatabaseConnection:
    # Database interface
    def cursor (self):
        "Returns a cursor object and starts a new transaction"
    def commit (self):
        "Commits current transaction"
    def rollback (self):
        "Rolls back current transaction"

The __enter__() method is pretty easy, having only to start a new transaction. For this application the resulting cursor object would be a useful result, so the method will return it. The user can then add as cursor to their ‘with’ statement to bind the cursor to a variable name.

class DatabaseConnection:
    ...
    def __enter__ (self):
        # Code to start a new transaction
        cursor = self.cursor()
        return cursor

The __exit__() method is the most complicated because it’s where most of the work has to be done. The method has to check if an exception occurred. If there was no exception, the transaction is committed. The transaction is rolled back if there was an exception.

In the code below, execution will just fall off the end of the function, returning the default value of None. None is false, so the exception will be re-raised automatically. If you wished, you could be more explicit and add a return statement at the marked location.

class DatabaseConnection:
    ...
    def __exit__ (self, type, value, tb):
        if tb is None:
            # No exception, so commit
            self.commit()
        else:
            # Exception occurred, so rollback.
            self.rollback()
            # return False

The contextlib module

The new contextlib module provides some functions and a decorator that are useful for writing objects for use with the ‘with’ statement.

The decorator is called contextmanager(), and lets you write a single generator function instead of defining a new class. The generator should yield exactly one value. The code up to the yield will be executed as the __enter__() method, and the value yielded will be the method’s return value that will get bound to the variable in the ‘with’ statement’s as clause, if any. The code after the yield will be executed in the __exit__() method. Any exception raised in the block will be raised by the yield statement.

Our database example from the previous section could be written using this decorator as:

from contextlib import contextmanager

@contextmanager
def db_transaction (connection):
    cursor = connection.cursor()
    try:
        yield cursor
    except:
        connection.rollback()
        raise
    else:
        connection.commit()

db = DatabaseConnection()
with db_transaction(db) as cursor:
    ...

The contextlib module also has a nested(mgr1, mgr2, ...) function that combines a number of context managers so you don’t need to write nested ‘with’ statements. In this example, the single ‘with’ statement both starts a database transaction and acquires a thread lock:

lock = threading.Lock()
with nested (db_transaction(db), lock) as (cursor, locked):
    ...

Finally, the closing(object) function returns object so that it can be bound to a variable, and calls object.close at the end of the block.

import urllib, sys
from contextlib import closing

with closing(urllib.urlopen('http://www.yahoo.com')) as f:
    for line in f:
        sys.stdout.write(line)

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PEP 343 [https://peps.python.org/pep-0343/] - The “with” statement

PEP written by Guido van Rossum and Nick Coghlan; implemented by Mike Bland, Guido van Rossum, and Neal Norwitz. The PEP shows the code generated for a ‘with’ statement, which can be helpful in learning how the statement works.

The documentation for the contextlib module.

PEP 352: Exceptions as New-Style Classes

Exception classes can now be new-style classes, not just classic classes, and the built-in Exception class and all the standard built-in exceptions (NameError, ValueError, etc.) are now new-style classes.

The inheritance hierarchy for exceptions has been rearranged a bit. In 2.5, the inheritance relationships are:

BaseException       # New in Python 2.5
|- KeyboardInterrupt
|- SystemExit
|- Exception
   |- (all other current built-in exceptions)

This rearrangement was done because people often want to catch all exceptions that indicate program errors. KeyboardInterrupt and SystemExit aren’t errors, though, and usually represent an explicit action such as the user hitting Control-C or code calling sys.exit(). A bare except: will catch all exceptions, so you commonly need to list KeyboardInterrupt and SystemExit in order to re-raise them. The usual pattern is:

try:
    ...
except (KeyboardInterrupt, SystemExit):
    raise
except:
    # Log error...
    # Continue running program...

In Python 2.5, you can now write except Exception to achieve the same result, catching all the exceptions that usually indicate errors but leaving KeyboardInterrupt and SystemExit alone. As in previous versions, a bare except: still catches all exceptions.

The goal for Python 3.0 is to require any class raised as an exception to derive from BaseException or some descendant of BaseException, and future releases in the Python 2.x series may begin to enforce this constraint. Therefore, I suggest you begin making all your exception classes derive from Exception now. It’s been suggested that the bare except: form should be removed in Python 3.0, but Guido van Rossum hasn’t decided whether to do this or not.

Raising of strings as exceptions, as in the statement raise "Error occurred", is deprecated in Python 2.5 and will trigger a warning. The aim is to be able to remove the string-exception feature in a few releases.

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PEP 352 [https://peps.python.org/pep-0352/] - Required Superclass for Exceptions

PEP written by Brett Cannon and Guido van Rossum; implemented by Brett Cannon.

PEP 353: Using ssize_t as the index type

A wide-ranging change to Python’s C API, using a new Py_ssize_t type definition instead of int, will permit the interpreter to handle more data on 64-bit platforms. This change doesn’t affect Python’s capacity on 32-bit platforms.

Various pieces of the Python interpreter used C’s int type to store sizes or counts; for example, the number of items in a list or tuple were stored in an int. The C compilers for most 64-bit platforms still define int as a 32-bit type, so that meant that lists could only hold up to 2**31 - 1 = 2147483647 items. (There are actually a few different programming models that 64-bit C compilers can use – see https://unix.org/version2/whatsnew/lp64_wp.html for a discussion – but the most commonly available model leaves int as 32 bits.)

A limit of 2147483647 items doesn’t really matter on a 32-bit platform because you’ll run out of memory before hitting the length limit. Each list item requires space for a pointer, which is 4 bytes, plus space for a PyObject representing the item. 2147483647*4 is already more bytes than a 32-bit address space can contain.

It’s possible to address that much memory on a 64-bit platform, however. The pointers for a list that size would only require 16 GiB of space, so it’s not unreasonable that Python programmers might construct lists that large. Therefore, the Python interpreter had to be changed to use some type other than int, and this will be a 64-bit type on 64-bit platforms. The change will cause incompatibilities on 64-bit machines, so it was deemed worth making the transition now, while the number of 64-bit users is still relatively small. (In 5 or 10 years, we may all be on 64-bit machines, and the transition would be more painful then.)

This change most strongly affects authors of C extension modules. Python strings and container types such as lists and tuples now use Py_ssize_t to store their size. Functions such as PyList_Size() now return Py_ssize_t. Code in extension modules may therefore need to have some variables changed to Py_ssize_t.

The PyArg_ParseTuple() and Py_BuildValue() functions have a new conversion code, n, for Py_ssize_t. PyArg_ParseTuple()’s s# and t# still output int by default, but you can define the macro PY_SSIZE_T_CLEAN before including Python.h to make them return Py_ssize_t.

PEP 353 [https://peps.python.org/pep-0353/] has a section on conversion guidelines that extension authors should read to learn about supporting 64-bit platforms.

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PEP 353 [https://peps.python.org/pep-0353/] - Using ssize_t as the index type

PEP written and implemented by Martin von Löwis.

PEP 357: The ‘__index__’ method

The NumPy developers had a problem that could only be solved by adding a new special method, __index__(). When using slice notation, as in [start:stop:step], the values of the start, stop, and step indexes must all be either integers or long integers. NumPy defines a variety of specialized integer types corresponding to unsigned and signed integers of 8, 16, 32, and 64 bits, but there was no way to signal that these types could be used as slice indexes.

Slicing can’t just use the existing __int__() method because that method is also used to implement coercion to integers. If slicing used __int__(), floating-point numbers would also become legal slice indexes and that’s clearly an undesirable behaviour.

Instead, a new special method called __index__() was added. It takes no arguments and returns an integer giving the slice index to use. For example:

class C:
    def __index__ (self):
        return self.value

The return value must be either a Python integer or long integer. The interpreter will check that the type returned is correct, and raises a TypeError if this requirement isn’t met.

A corresponding nb_index slot was added to the C-level PyNumberMethods structure to let C extensions implement this protocol. PyNumber_Index(obj) can be used in extension code to call the __index__() function and retrieve its result.

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PEP 357 [https://peps.python.org/pep-0357/] - Allowing Any Object to be Used for Slicing

PEP written and implemented by Travis Oliphant.

Other Language Changes

Here are all of the changes that Python 2.5 makes to the core Python language.

The dict type has a new hook for letting subclasses provide a default value when a key isn’t contained in the dictionary. When a key isn’t found, the dictionary’s __missing__(key) method will be called. This hook is used to implement the new defaultdict class in the collections module. The following example defines a dictionary that returns zero for any missing key:

class zerodict (dict):
    def __missing__ (self, key):
        return 0

d = zerodict({1:1, 2:2})
print d[1], d[2]   # Prints 1, 2
print d[3], d[4]   # Prints 0, 0

Both 8-bit and Unicode strings have new partition(sep) and rpartition(sep) methods that simplify a common use case.

The find(S) method is often used to get an index which is then used to slice the string and obtain the pieces that are before and after the separator. partition(sep) condenses this pattern into a single method call that returns a 3-tuple containing the substring before the separator, the separator itself, and the substring after the separator. If the separator isn’t found, the first element of the tuple is the entire string and the other two elements are empty. rpartition(sep) also returns a 3-tuple but starts searching from the end of the string; the r stands for ‘reverse’.

Some examples:

>>> ('http://www.python.org').partition('://')
('http', '://', 'www.python.org')
>>> ('file:/usr/share/doc/index.html').partition('://')
('file:/usr/share/doc/index.html', '', '')
>>> (u'Subject: a quick question').partition(':')
(u'Subject', u':', u' a quick question')
>>> 'www.python.org'.rpartition('.')
('www.python', '.', 'org')
>>> 'www.python.org'.rpartition(':')
('', '', 'www.python.org')

(Implemented by Fredrik Lundh following a suggestion by Raymond Hettinger.)

The startswith() and endswith() methods of string types now accept tuples of strings to check for.

def is_image_file (filename):
    return filename.endswith(('.gif', '.jpg', '.tiff'))

(Implemented by Georg Brandl following a suggestion by Tom Lynn.)

The min() and max() built-in functions gained a key keyword parameter analogous to the key argument for sort(). This parameter supplies a function that takes a single argument and is called for every value in the list; min()/max() will return the element with the smallest/largest return value from this function. For example, to find the longest string in a list, you can do:

L = ['medium', 'longest', 'short']
# Prints 'longest'
print max(L, key=len)
# Prints 'short', because lexicographically 'short' has the largest value
print max(L)

(Contributed by Steven Bethard and Raymond Hettinger.)

Two new built-in functions, any() and all(), evaluate whether an iterator contains any true or false values. any() returns True if any value returned by the iterator is true; otherwise it will return False. all() returns True only if all of the values returned by the iterator evaluate as true. (Suggested by Guido van Rossum, and implemented by Raymond Hettinger.)

The result of a class’s __hash__() method can now be either a long integer or a regular integer. If a long integer is returned, the hash of that value is taken. In earlier versions the hash value was required to be a regular integer, but in 2.5 the id() built-in was changed to always return non-negative numbers, and users often seem to use id(self) in __hash__() methods (though this is discouraged).

ASCII is now the default encoding for modules. It’s now a syntax error if a module contains string literals with 8-bit characters but doesn’t have an encoding declaration. In Python 2.4 this triggered a warning, not a syntax error. See PEP 263 [https://peps.python.org/pep-0263/] for how to declare a module’s encoding; for example, you might add a line like this near the top of the source file:

# -*- coding: latin1 -*-

A new warning, UnicodeWarning, is triggered when you attempt to compare a Unicode string and an 8-bit string that can’t be converted to Unicode using the default ASCII encoding. The result of the comparison is false:

>>> chr(128) == unichr(128)   # Can't convert chr(128) to Unicode
__main__:1: UnicodeWarning: Unicode equal comparison failed
  to convert both arguments to Unicode - interpreting them
  as being unequal
False
>>> chr(127) == unichr(127)   # chr(127) can be converted
True

Previously this would raise a UnicodeDecodeError exception, but in 2.5 this could result in puzzling problems when accessing a dictionary. If you looked up unichr(128) and chr(128) was being used as a key, you’d get a UnicodeDecodeError exception. Other changes in 2.5 resulted in this exception being raised instead of suppressed by the code in dictobject.c that implements dictionaries.

Raising an exception for such a comparison is strictly correct, but the change might have broken code, so instead UnicodeWarning was introduced.

(Implemented by Marc-André Lemburg.)

One error that Python programmers sometimes make is forgetting to include an __init__.py module in a package directory. Debugging this mistake can be confusing, and usually requires running Python with the -v switch to log all the paths searched. In Python 2.5, a new ImportWarning warning is triggered when an import would have picked up a directory as a package but no __init__.py was found. This warning is silently ignored by default; provide the -Wd option when running the Python executable to display the warning message. (Implemented by Thomas Wouters.)

The list of base classes in a class definition can now be empty. As an example, this is now legal:

class C():
    pass

(Implemented by Brett Cannon.)

Interactive Interpreter Changes

In the interactive interpreter, quit and exit have long been strings so that new users get a somewhat helpful message when they try to quit:

>>> quit
'Use Ctrl-D (i.e. EOF) to exit.'

In Python 2.5, quit and exit are now objects that still produce string representations of themselves, but are also callable. Newbies who try quit() or exit() will now exit the interpreter as they expect. (Implemented by Georg Brandl.)

The Python executable now accepts the standard long options --help and --version; on Windows, it also accepts the /? option for displaying a help message. (Implemented by Georg Brandl.)

Optimizations

Several of the optimizations were developed at the NeedForSpeed sprint, an event held in Reykjavik, Iceland, from May 21–28 2006. The sprint focused on speed enhancements to the CPython implementation and was funded by EWT LLC with local support from CCP Games. Those optimizations added at this sprint are specially marked in the following list.

When they were introduced in Python 2.4, the built-in set and frozenset types were built on top of Python’s dictionary type. In 2.5 the internal data structure has been customized for implementing sets, and as a result sets will use a third less memory and are somewhat faster. (Implemented by Raymond Hettinger.)

The speed of some Unicode operations, such as finding substrings, string splitting, and character map encoding and decoding, has been improved. (Substring search and splitting improvements were added by Fredrik Lundh and Andrew Dalke at the NeedForSpeed sprint. Character maps were improved by Walter Dörwald and Martin von Löwis.)

The long(str, base) function is now faster on long digit strings because fewer intermediate results are calculated. The peak is for strings of around 800–1000 digits where the function is 6 times faster. (Contributed by Alan McIntyre and committed at the NeedForSpeed sprint.)

It’s now illegal to mix iterating over a file with for line in file and calling the file object’s read()/readline()/readlines() methods. Iteration uses an internal buffer and the read*() methods don’t use that buffer. Instead they would return the data following the buffer, causing the data to appear out of order. Mixing iteration and these methods will now trigger a ValueError from the read*() method. (Implemented by Thomas Wouters.)

The struct module now compiles structure format strings into an internal representation and caches this representation, yielding a 20% speedup. (Contributed by Bob Ippolito at the NeedForSpeed sprint.)

The re module got a 1 or 2% speedup by switching to Python’s allocator functions instead of the system’s malloc() and free(). (Contributed by Jack Diederich at the NeedForSpeed sprint.)

The code generator’s peephole optimizer now performs simple constant folding in expressions. If you write something like a = 2+3, the code generator will do the arithmetic and produce code corresponding to a = 5. (Proposed and implemented by Raymond Hettinger.)

Function calls are now faster because code objects now keep the most recently finished frame (a “zombie frame”) in an internal field of the code object, reusing it the next time the code object is invoked. (Original patch by Michael Hudson, modified by Armin Rigo and Richard Jones; committed at the NeedForSpeed sprint.) Frame objects are also slightly smaller, which may improve cache locality and reduce memory usage a bit. (Contributed by Neal Norwitz.)

Python’s built-in exceptions are now new-style classes, a change that speeds up instantiation considerably. Exception handling in Python 2.5 is therefore about 30% faster than in 2.4. (Contributed by Richard Jones, Georg Brandl and Sean Reifschneider at the NeedForSpeed sprint.)

Importing now caches the paths tried, recording whether they exist or not so that the interpreter makes fewer open() and stat() calls on startup. (Contributed by Martin von Löwis and Georg Brandl.)

New, Improved, and Removed Modules

The standard library received many enhancements and bug fixes in Python 2.5. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the Misc/NEWS file in the source tree for a more complete list of changes, or look through the SVN logs for all the details.

The audioop module now supports the a-LAW encoding, and the code for u-LAW encoding has been improved. (Contributed by Lars Immisch.)

The codecs module gained support for incremental codecs. The codec.lookup() function now returns a CodecInfo instance instead of a tuple. CodecInfo instances behave like a 4-tuple to preserve backward compatibility but also have the attributes encode, decode, incrementalencoder, incrementaldecoder, streamwriter, and streamreader. Incremental codecs can receive input and produce output in multiple chunks; the output is the same as if the entire input was fed to the non-incremental codec. See the codecs module documentation for details. (Designed and implemented by Walter Dörwald.)

The collections module gained a new type, defaultdict, that subclasses the standard dict type. The new type mostly behaves like a dictionary but constructs a default value when a key isn’t present, automatically adding it to the dictionary for the requested key value.

The first argument to defaultdict’s constructor is a factory function that gets called whenever a key is requested but not found. This factory function receives no arguments, so you can use built-in type constructors such as list() or int(). For example, you can make an index of words based on their initial letter like this:

words = """Nel mezzo del cammin di nostra vita
mi ritrovai per una selva oscura
che la diritta via era smarrita""".lower().split()

index = defaultdict(list)

for w in words:
    init_letter = w[0]
    index[init_letter].append(w)

Printing index results in the following output:

defaultdict(<type 'list'>, {'c': ['cammin', 'che'], 'e': ['era'],
        'd': ['del', 'di', 'diritta'], 'm': ['mezzo', 'mi'],
        'l': ['la'], 'o': ['oscura'], 'n': ['nel', 'nostra'],
        'p': ['per'], 's': ['selva', 'smarrita'],
        'r': ['ritrovai'], 'u': ['una'], 'v': ['vita', 'via']}

(Contributed by Guido van Rossum.)

The deque double-ended queue type supplied by the collections module now has a remove(value) method that removes the first occurrence of value in the queue, raising ValueError if the value isn’t found. (Contributed by Raymond Hettinger.)

New module: The contextlib module contains helper functions for use with the new ‘with’ statement. See section The contextlib module for more about this module.

New module: The cProfile module is a C implementation of the existing profile module that has much lower overhead. The module’s interface is the same as profile: you run cProfile.run('main()') to profile a function, can save profile data to a file, etc. It’s not yet known if the Hotshot profiler, which is also written in C but doesn’t match the profile module’s interface, will continue to be maintained in future versions of Python. (Contributed by Armin Rigo.)

Also, the pstats module for analyzing the data measured by the profiler now supports directing the output to any file object by supplying a stream argument to the Stats constructor. (Contributed by Skip Montanaro.)

The csv module, which parses files in comma-separated value format, received several enhancements and a number of bugfixes. You can now set the maximum size in bytes of a field by calling the csv.field_size_limit(new_limit) function; omitting the new_limit argument will return the currently set limit. The reader class now has a line_num attribute that counts the number of physical lines read from the source; records can span multiple physical lines, so line_num is not the same as the number of records read.

The CSV parser is now stricter about multi-line quoted fields. Previously, if a line ended within a quoted field without a terminating newline character, a newline would be inserted into the returned field. This behavior caused problems when reading files that contained carriage return characters within fields, so the code was changed to return the field without inserting newlines. As a consequence, if newlines embedded within fields are important, the input should be split into lines in a manner that preserves the newline characters.

(Contributed by Skip Montanaro and Andrew McNamara.)

The datetime class in the datetime module now has a strptime(string, format) method for parsing date strings, contributed by Josh Spoerri. It uses the same format characters as time.strptime() and time.strftime():

from datetime import datetime

ts = datetime.strptime('10:13:15 2006-03-07',
                       '%H:%M:%S %Y-%m-%d')

The SequenceMatcher.get_matching_blocks() method in the difflib module now guarantees to return a minimal list of blocks describing matching subsequences. Previously, the algorithm would occasionally break a block of matching elements into two list entries. (Enhancement by Tim Peters.)

The doctest module gained a SKIP option that keeps an example from being executed at all. This is intended for code snippets that are usage examples intended for the reader and aren’t actually test cases.

An encoding parameter was added to the testfile() function and the DocFileSuite class to specify the file’s encoding. This makes it easier to use non-ASCII characters in tests contained within a docstring. (Contributed by Bjorn Tillenius.)

The email package has been updated to version 4.0. (Contributed by Barry Warsaw.)

The fileinput module was made more flexible. Unicode filenames are now supported, and a mode parameter that defaults to "r" was added to the input() function to allow opening files in binary or universal newlines mode. Another new parameter, openhook, lets you use a function other than open() to open the input files. Once you’re iterating over the set of files, the FileInput object’s new fileno() returns the file descriptor for the currently opened file. (Contributed by Georg Brandl.)

In the gc module, the new get_count() function returns a 3-tuple containing the current collection counts for the three GC generations. This is accounting information for the garbage collector; when these counts reach a specified threshold, a garbage collection sweep will be made. The existing gc.collect() function now takes an optional generation argument of 0, 1, or 2 to specify which generation to collect. (Contributed by Barry Warsaw.)

The nsmallest() and nlargest() functions in the heapq module now support a key keyword parameter similar to the one provided by the min()/max() functions and the sort() methods. For example:

>>> import heapq
>>> L = ["short", 'medium', 'longest', 'longer still']
>>> heapq.nsmallest(2, L)  # Return two lowest elements, lexicographically
['longer still', 'longest']
>>> heapq.nsmallest(2, L, key=len)   # Return two shortest elements
['short', 'medium']

(Contributed by Raymond Hettinger.)

The itertools.islice() function now accepts None for the start and step arguments. This makes it more compatible with the attributes of slice objects, so that you can now write the following:

s = slice(5)     # Create slice object
itertools.islice(iterable, s.start, s.stop, s.step)

(Contributed by Raymond Hettinger.)

The format() function in the locale module has been modified and two new functions were added, format_string() and currency().

The format() function’s val parameter could previously be a string as long as no more than one %char specifier appeared; now the parameter must be exactly one %char specifier with no surrounding text. An optional monetary parameter was also added which, if True, will use the locale’s rules for formatting currency in placing a separator between groups of three digits.

To format strings with multiple %char specifiers, use the new format_string() function that works like format() but also supports mixing %char specifiers with arbitrary text.

A new currency() function was also added that formats a number according to the current locale’s settings.

(Contributed by Georg Brandl.)

The mailbox module underwent a massive rewrite to add the capability to modify mailboxes in addition to reading them. A new set of classes that include mbox, MH, and Maildir are used to read mailboxes, and have an add(message) method to add messages, remove(key) to remove messages, and lock()/unlock() to lock/unlock the mailbox. The following example converts a maildir-format mailbox into an mbox-format one:

import mailbox

# 'factory=None' uses email.Message.Message as the class representing
# individual messages.
src = mailbox.Maildir('maildir', factory=None)
dest = mailbox.mbox('/tmp/mbox')

for msg in src:
    dest.add(msg)

(Contributed by Gregory K. Johnson. Funding was provided by Google’s 2005 Summer of Code.)

New module: the msilib module allows creating Microsoft Installer .msi files and CAB files. Some support for reading the .msi database is also included. (Contributed by Martin von Löwis.)

The nis module now supports accessing domains other than the system default domain by supplying a domain argument to the nis.match() and nis.maps() functions. (Contributed by Ben Bell.)

The operator module’s itemgetter() and attrgetter() functions now support multiple fields. A call such as operator.attrgetter('a', 'b') will return a function that retrieves the a and b attributes. Combining this new feature with the sort() method’s key parameter lets you easily sort lists using multiple fields. (Contributed by Raymond Hettinger.)

The optparse module was updated to version 1.5.1 of the Optik library. The OptionParser class gained an epilog attribute, a string that will be printed after the help message, and a destroy() method to break reference cycles created by the object. (Contributed by Greg Ward.)

The os module underwent several changes. The stat_float_times variable now defaults to true, meaning that os.stat() will now return time values as floats. (This doesn’t necessarily mean that os.stat() will return times that are precise to fractions of a second; not all systems support such precision.)

Constants named os.SEEK_SET, os.SEEK_CUR, and os.SEEK_END have been added; these are the parameters to the os.lseek() function. Two new constants for locking are os.O_SHLOCK and os.O_EXLOCK.

Two new functions, wait3() and wait4(), were added. They’re similar the waitpid() function which waits for a child process to exit and returns a tuple of the process ID and its exit status, but wait3() and wait4() return additional information. wait3() doesn’t take a process ID as input, so it waits for any child process to exit and returns a 3-tuple of process-id, exit-status, resource-usage as returned from the resource.getrusage() function. wait4(pid) does take a process ID. (Contributed by Chad J. Schroeder.)

On FreeBSD, the os.stat() function now returns times with nanosecond resolution, and the returned object now has st_gen and st_birthtime. The st_flags attribute is also available, if the platform supports it. (Contributed by Antti Louko and Diego Pettenò.)

The Python debugger provided by the pdb module can now store lists of commands to execute when a breakpoint is reached and execution stops. Once breakpoint #1 has been created, enter commands 1 and enter a series of commands to be executed, finishing the list with end. The command list can include commands that resume execution, such as continue or next. (Contributed by Grégoire Dooms.)

The pickle and cPickle modules no longer accept a return value of None from the __reduce__() method; the method must return a tuple of arguments instead. The ability to return None was deprecated in Python 2.4, so this completes the removal of the feature.

The pkgutil module, containing various utility functions for finding packages, was enhanced to support PEP 302 [https://peps.python.org/pep-0302/]’s import hooks and now also works for packages stored in ZIP-format archives. (Contributed by Phillip J. Eby.)

The pybench benchmark suite by Marc-André Lemburg is now included in the Tools/pybench directory. The pybench suite is an improvement on the commonly used pystone.py program because pybench provides a more detailed measurement of the interpreter’s speed. It times particular operations such as function calls, tuple slicing, method lookups, and numeric operations, instead of performing many different operations and reducing the result to a single number as pystone.py does.

The pyexpat module now uses version 2.0 of the Expat parser. (Contributed by Trent Mick.)

The Queue class provided by the Queue module gained two new methods. join() blocks until all items in the queue have been retrieved and all processing work on the items have been completed. Worker threads call the other new method, task_done(), to signal that processing for an item has been completed. (Contributed by Raymond Hettinger.)

The old regex and regsub modules, which have been deprecated ever since Python 2.0, have finally been deleted. Other deleted modules: statcache, tzparse, whrandom.

Also deleted: the lib-old directory, which includes ancient modules such as dircmp and ni, was removed. lib-old wasn’t on the default sys.path, so unless your programs explicitly added the directory to sys.path, this removal shouldn’t affect your code.

The rlcompleter module is no longer dependent on importing the readline module and therefore now works on non-Unix platforms. (Patch from Robert Kiendl.)

The SimpleXMLRPCServer and DocXMLRPCServer classes now have a rpc_paths attribute that constrains XML-RPC operations to a limited set of URL paths; the default is to allow only '/' and '/RPC2'. Setting rpc_paths to None or an empty tuple disables this path checking.

The socket module now supports AF_NETLINK sockets on Linux, thanks to a patch from Philippe Biondi. Netlink sockets are a Linux-specific mechanism for communications between a user-space process and kernel code; an introductory article about them is at https://www.linuxjournal.com/article/7356. In Python code, netlink addresses are represented as a tuple of 2 integers, (pid, group_mask).

Two new methods on socket objects, recv_into(buffer) and recvfrom_into(buffer), store the received data in an object that supports the buffer protocol instead of returning the data as a string. This means you can put the data directly into an array or a memory-mapped file.

Socket objects also gained getfamily(), gettype(), and getproto() accessor methods to retrieve the family, type, and protocol values for the socket.

New module: the spwd module provides functions for accessing the shadow password database on systems that support shadow passwords.

The struct is now faster because it compiles format strings into Struct objects with pack() and unpack() methods. This is similar to how the re module lets you create compiled regular expression objects. You can still use the module-level pack() and unpack() functions; they’ll create Struct objects and cache them. Or you can use Struct instances directly:

s = struct.Struct('ih3s')

data = s.pack(1972, 187, 'abc')
year, number, name = s.unpack(data)

You can also pack and unpack data to and from buffer objects directly using the pack_into(buffer, offset, v1, v2, ...) and unpack_from(buffer, offset) methods. This lets you store data directly into an array or a memory-mapped file.

(Struct objects were implemented by Bob Ippolito at the NeedForSpeed sprint. Support for buffer objects was added by Martin Blais, also at the NeedForSpeed sprint.)

The Python developers switched from CVS to Subversion during the 2.5 development process. Information about the exact build version is available as the sys.subversion variable, a 3-tuple of (interpreter-name, branch-name, revision-range). For example, at the time of writing my copy of 2.5 was reporting ('CPython', 'trunk', '45313:45315').

This information is also available to C extensions via the Py_GetBuildInfo() function that returns a string of build information like this: "trunk:45355:45356M, Apr 13 2006, 07:42:19". (Contributed by Barry Warsaw.)

Another new function, sys._current_frames(), returns the current stack frames for all running threads as a dictionary mapping thread identifiers to the topmost stack frame currently active in that thread at the time the function is called. (Contributed by Tim Peters.)

The TarFile class in the tarfile module now has an extractall() method that extracts all members from the archive into the current working directory. It’s also possible to set a different directory as the extraction target, and to unpack only a subset of the archive’s members.

The compression used for a tarfile opened in stream mode can now be autodetected using the mode 'r|*'. (Contributed by Lars Gustäbel.)

The threading module now lets you set the stack size used when new threads are created. The stack_size([*size*]) function returns the currently configured stack size, and supplying the optional size parameter sets a new value. Not all platforms support changing the stack size, but Windows, POSIX threading, and OS/2 all do. (Contributed by Andrew MacIntyre.)

The unicodedata module has been updated to use version 4.1.0 of the Unicode character database. Version 3.2.0 is required by some specifications, so it’s still available as unicodedata.ucd_3_2_0.

New module: the uuid module generates universally unique identifiers (UUIDs) according to RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html]. The RFC defines several different UUID versions that are generated from a starting string, from system properties, or purely randomly. This module contains a UUID class and functions named uuid1(), uuid3(), uuid4(), and uuid5() to generate different versions of UUID. (Version 2 UUIDs are not specified in RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html] and are not supported by this module.)

>>> import uuid
>>> # make a UUID based on the host ID and current time
>>> uuid.uuid1()
UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')

>>> # make a UUID using an MD5 hash of a namespace UUID and a name
>>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')

>>> # make a random UUID
>>> uuid.uuid4()
UUID('16fd2706-8baf-433b-82eb-8c7fada847da')

>>> # make a UUID using a SHA-1 hash of a namespace UUID and a name
>>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')

(Contributed by Ka-Ping Yee.)

The weakref module’s WeakKeyDictionary and WeakValueDictionary types gained new methods for iterating over the weak references contained in the dictionary. iterkeyrefs() and keyrefs() methods were added to WeakKeyDictionary, and itervaluerefs() and valuerefs() were added to WeakValueDictionary. (Contributed by Fred L. Drake, Jr.)

The webbrowser module received a number of enhancements. It’s now usable as a script with python -m webbrowser, taking a URL as the argument; there are a number of switches to control the behaviour (-n for a new browser window, -t for a new tab). New module-level functions, open_new() and open_new_tab(), were added to support this. The module’s open() function supports an additional feature, an autoraise parameter that signals whether to raise the open window when possible. A number of additional browsers were added to the supported list such as Firefox, Opera, Konqueror, and elinks. (Contributed by Oleg Broytmann and Georg Brandl.)

The xmlrpclib module now supports returning datetime objects for the XML-RPC date type. Supply use_datetime=True to the loads() function or the Unmarshaller class to enable this feature. (Contributed by Skip Montanaro.)

The zipfile module now supports the ZIP64 version of the format, meaning that a .zip archive can now be larger than 4 GiB and can contain individual files larger than 4 GiB. (Contributed by Ronald Oussoren.)

The zlib module’s Compress and Decompress objects now support a copy() method that makes a copy of the object’s internal state and returns a new Compress or Decompress object. (Contributed by Chris AtLee.)

The ctypes package

The ctypes package, written by Thomas Heller, has been added to the standard library. ctypes lets you call arbitrary functions in shared libraries or DLLs. Long-time users may remember the dl module, which provides functions for loading shared libraries and calling functions in them. The ctypes package is much fancier.

To load a shared library or DLL, you must create an instance of the CDLL class and provide the name or path of the shared library or DLL. Once that’s done, you can call arbitrary functions by accessing them as attributes of the CDLL object.

import ctypes

libc = ctypes.CDLL('libc.so.6')
result = libc.printf("Line of output\n")

Type constructors for the various C types are provided: c_int(), c_float(), c_double(), c_char_p() (equivalent to char*), and so forth. Unlike Python’s types, the C versions are all mutable; you can assign to their value attribute to change the wrapped value. Python integers and strings will be automatically converted to the corresponding C types, but for other types you must call the correct type constructor. (And I mean must; getting it wrong will often result in the interpreter crashing with a segmentation fault.)

You shouldn’t use c_char_p() with a Python string when the C function will be modifying the memory area, because Python strings are supposed to be immutable; breaking this rule will cause puzzling bugs. When you need a modifiable memory area, use create_string_buffer():

s = "this is a string"
buf = ctypes.create_string_buffer(s)
libc.strfry(buf)

C functions are assumed to return integers, but you can set the restype attribute of the function object to change this:

>>> libc.atof('2.71828')
-1783957616
>>> libc.atof.restype = ctypes.c_double
>>> libc.atof('2.71828')
2.71828

ctypes also provides a wrapper for Python’s C API as the ctypes.pythonapi object. This object does not release the global interpreter lock before calling a function, because the lock must be held when calling into the interpreter’s code. There’s a py_object type constructor that will create a PyObject* pointer. A simple usage:

import ctypes

d = {}
ctypes.pythonapi.PyObject_SetItem(ctypes.py_object(d),
          ctypes.py_object("abc"),  ctypes.py_object(1))
# d is now {'abc', 1}.

Don’t forget to use py_object(); if it’s omitted you end up with a segmentation fault.

ctypes has been around for a while, but people still write and distribution hand-coded extension modules because you can’t rely on ctypes being present. Perhaps developers will begin to write Python wrappers atop a library accessed through ctypes instead of extension modules, now that ctypes is included with core Python.

더 보기

https://web.archive.org/web/20180410025338/http://starship.python.net/crew/theller/ctypes/

The pre-stdlib ctypes web page, with a tutorial, reference, and FAQ.

The documentation for the ctypes module.

The ElementTree package

A subset of Fredrik Lundh’s ElementTree library for processing XML has been added to the standard library as xml.etree. The available modules are ElementTree, ElementPath, and ElementInclude from ElementTree 1.2.6. The cElementTree accelerator module is also included.

The rest of this section will provide a brief overview of using ElementTree. Full documentation for ElementTree is available at https://web.archive.org/web/20201124024954/http://effbot.org/zone/element-index.htm.

ElementTree represents an XML document as a tree of element nodes. The text content of the document is stored as the text and tail attributes of (This is one of the major differences between ElementTree and the Document Object Model; in the DOM there are many different types of node, including TextNode.)

The most commonly used parsing function is parse(), that takes either a string (assumed to contain a filename) or a file-like object and returns an ElementTree instance:

from xml.etree import ElementTree as ET

tree = ET.parse('ex-1.xml')

feed = urllib.urlopen(
          'http://planet.python.org/rss10.xml')
tree = ET.parse(feed)

Once you have an ElementTree instance, you can call its getroot() method to get the root Element node.

There’s also an XML() function that takes a string literal and returns an Element node (not an ElementTree). This function provides a tidy way to incorporate XML fragments, approaching the convenience of an XML literal:

svg = ET.XML("""<svg width="10px" version="1.0">
             </svg>""")
svg.set('height', '320px')
svg.append(elem1)

Each XML element supports some dictionary-like and some list-like access methods. Dictionary-like operations are used to access attribute values, and list-like operations are used to access child nodes.

Operation

Result

elem[n]

Returns n’th child element.

elem[m:n]

Returns list of m’th through n’th child elements.

len(elem)

Returns number of child elements.

list(elem)

Returns list of child elements.

elem.append(elem2)

Adds elem2 as a child.

elem.insert(index, elem2)

Inserts elem2 at the specified location.

del elem[n]

Deletes n’th child element.

elem.keys()

Returns list of attribute names.

elem.get(name)

Returns value of attribute name.

elem.set(name, value)

Sets new value for attribute name.

elem.attrib

Retrieves the dictionary containing attributes.

del elem.attrib[name]

Deletes attribute name.

Comments and processing instructions are also represented as Element nodes. To check if a node is a comment or processing instructions:

if elem.tag is ET.Comment:
    ...
elif elem.tag is ET.ProcessingInstruction:
    ...

To generate XML output, you should call the ElementTree.write() method. Like parse(), it can take either a string or a file-like object:

# Encoding is US-ASCII
tree.write('output.xml')

# Encoding is UTF-8
f = open('output.xml', 'w')
tree.write(f, encoding='utf-8')

(Caution: the default encoding used for output is ASCII. For general XML work, where an element’s name may contain arbitrary Unicode characters, ASCII isn’t a very useful encoding because it will raise an exception if an element’s name contains any characters with values greater than 127. Therefore, it’s best to specify a different encoding such as UTF-8 that can handle any Unicode character.)

This section is only a partial description of the ElementTree interfaces. Please read the package’s official documentation for more details.

더 보기

https://web.archive.org/web/20201124024954/http://effbot.org/zone/element-index.htm

Official documentation for ElementTree.

The hashlib package

A new hashlib module, written by Gregory P. Smith, has been added to replace the md5 and sha modules. hashlib adds support for additional secure hashes (SHA-224, SHA-256, SHA-384, and SHA-512). When available, the module uses OpenSSL for fast platform optimized implementations of algorithms.

The old md5 and sha modules still exist as wrappers around hashlib to preserve backwards compatibility. The new module’s interface is very close to that of the old modules, but not identical. The most significant difference is that the constructor functions for creating new hashing objects are named differently.

# Old versions
h = md5.md5()
h = md5.new()

# New version
h = hashlib.md5()

# Old versions
h = sha.sha()
h = sha.new()

# New version
h = hashlib.sha1()

# Hash that weren't previously available
h = hashlib.sha224()
h = hashlib.sha256()
h = hashlib.sha384()
h = hashlib.sha512()

# Alternative form
h = hashlib.new('md5')          # Provide algorithm as a string

Once a hash object has been created, its methods are the same as before: update(string) hashes the specified string into the current digest state, digest() and hexdigest() return the digest value as a binary string or a string of hex digits, and copy() returns a new hashing object with the same digest state.

더 보기

The documentation for the hashlib module.

The sqlite3 package

The pysqlite module (https://www.pysqlite.org), a wrapper for the SQLite embedded database, has been added to the standard library under the package name sqlite3.

SQLite is a C library that provides a lightweight disk-based database that doesn’t require a separate server process and allows accessing the database using a nonstandard variant of the SQL query language. Some applications can use SQLite for internal data storage. It’s also possible to prototype an application using SQLite and then port the code to a larger database such as PostgreSQL or Oracle.

pysqlite was written by Gerhard Häring and provides a SQL interface compliant with the DB-API 2.0 specification described by PEP 249 [https://peps.python.org/pep-0249/].

If you’re compiling the Python source yourself, note that the source tree doesn’t include the SQLite code, only the wrapper module. You’ll need to have the SQLite libraries and headers installed before compiling Python, and the build process will compile the module when the necessary headers are available.

To use the module, you must first create a Connection object that represents the database. Here the data will be stored in the /tmp/example file:

conn = sqlite3.connect('/tmp/example')

You can also supply the special name :memory: to create a database in RAM.

Once you have a Connection, you can create a Cursor object and call its execute() method to perform SQL commands:

c = conn.cursor()

# Create table
c.execute('''create table stocks
(date text, trans text, symbol text,
 qty real, price real)''')

# Insert a row of data
c.execute("""insert into stocks
          values ('2006-01-05','BUY','RHAT',100,35.14)""")

Usually your SQL operations will need to use values from Python variables. You shouldn’t assemble your query using Python’s string operations because doing so is insecure; it makes your program vulnerable to an SQL injection attack.

Instead, use the DB-API’s parameter substitution. Put ? as a placeholder wherever you want to use a value, and then provide a tuple of values as the second argument to the cursor’s execute() method. (Other database modules may use a different placeholder, such as %s or :1.) For example:

# Never do this -- insecure!
symbol = 'IBM'
c.execute("... where symbol = '%s'" % symbol)

# Do this instead
t = (symbol,)
c.execute('select * from stocks where symbol=?', t)

# Larger example
for t in (('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
          ('2006-04-05', 'BUY', 'MSOFT', 1000, 72.00),
          ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
         ):
    c.execute('insert into stocks values (?,?,?,?,?)', t)

To retrieve data after executing a SELECT statement, you can either treat the cursor as an iterator, call the cursor’s fetchone() method to retrieve a single matching row, or call fetchall() to get a list of the matching rows.

This example uses the iterator form:

>>> c = conn.cursor()
>>> c.execute('select * from stocks order by price')
>>> for row in c:
...    print row
...
(u'2006-01-05', u'BUY', u'RHAT', 100, 35.140000000000001)
(u'2006-03-28', u'BUY', u'IBM', 1000, 45.0)
(u'2006-04-06', u'SELL', u'IBM', 500, 53.0)
(u'2006-04-05', u'BUY', u'MSOFT', 1000, 72.0)
>>>

For more information about the SQL dialect supported by SQLite, see https://www.sqlite.org.

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https://www.pysqlite.org

The pysqlite web page.

https://www.sqlite.org

The SQLite web page; the documentation describes the syntax and the available data types for the supported SQL dialect.

The documentation for the sqlite3 module.

PEP 249 [https://peps.python.org/pep-0249/] - Database API Specification 2.0

PEP written by Marc-André Lemburg.

The wsgiref package

The Web Server Gateway Interface (WSGI) v1.0 defines a standard interface between web servers and Python web applications and is described in PEP 333 [https://peps.python.org/pep-0333/]. The wsgiref package is a reference implementation of the WSGI specification.

The package includes a basic HTTP server that will run a WSGI application; this server is useful for debugging but isn’t intended for production use. Setting up a server takes only a few lines of code:

from wsgiref import simple_server

wsgi_app = ...

host = ''
port = 8000
httpd = simple_server.make_server(host, port, wsgi_app)
httpd.serve_forever()

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https://web.archive.org/web/20160331090247/http://wsgi.readthedocs.org/en/latest/

A central web site for WSGI-related resources.

PEP 333 [https://peps.python.org/pep-0333/] - Python Web Server Gateway Interface v1.0

PEP written by Phillip J. Eby.

Build and C API Changes

Changes to Python’s build process and to the C API include:

The Python source tree was converted from CVS to Subversion, in a complex migration procedure that was supervised and flawlessly carried out by Martin von Löwis. The procedure was developed as PEP 347 [https://peps.python.org/pep-0347/].

Coverity, a company that markets a source code analysis tool called Prevent, provided the results of their examination of the Python source code. The analysis found about 60 bugs that were quickly fixed. Many of the bugs were refcounting problems, often occurring in error-handling code. See https://scan.coverity.com for the statistics.

The largest change to the C API came from PEP 353 [https://peps.python.org/pep-0353/], which modifies the interpreter to use a Py_ssize_t type definition instead of int. See the earlier section PEP 353: Using ssize_t as the index type for a discussion of this change.

The design of the bytecode compiler has changed a great deal, no longer generating bytecode by traversing the parse tree. Instead the parse tree is converted to an abstract syntax tree (or AST), and it is the abstract syntax tree that’s traversed to produce the bytecode.

It’s possible for Python code to obtain AST objects by using the compile() built-in and specifying _ast.PyCF_ONLY_AST as the value of the flags parameter:

from _ast import PyCF_ONLY_AST
ast = compile("""a=0
for i in range(10):
    a += i
""", "<string>", 'exec', PyCF_ONLY_AST)

assignment = ast.body[0]
for_loop = ast.body[1]

No official documentation has been written for the AST code yet, but PEP 339 [https://peps.python.org/pep-0339/] discusses the design. To start learning about the code, read the definition of the various AST nodes in Parser/Python.asdl. A Python script reads this file and generates a set of C structure definitions in Include/Python-ast.h. The PyParser_ASTFromString() and PyParser_ASTFromFile(), defined in Include/pythonrun.h, take Python source as input and return the root of an AST representing the contents. This AST can then be turned into a code object by PyAST_Compile(). For more information, read the source code, and then ask questions on python-dev.

The AST code was developed under Jeremy Hylton’s management, and implemented by (in alphabetical order) Brett Cannon, Nick Coghlan, Grant Edwards, John Ehresman, Kurt Kaiser, Neal Norwitz, Tim Peters, Armin Rigo, and Neil Schemenauer, plus the participants in a number of AST sprints at conferences such as PyCon.

Evan Jones’s patch to obmalloc, first described in a talk at PyCon DC 2005, was applied. Python 2.4 allocated small objects in 256K-sized arenas, but never freed arenas. With this patch, Python will free arenas when they’re empty. The net effect is that on some platforms, when you allocate many objects, Python’s memory usage may actually drop when you delete them and the memory may be returned to the operating system. (Implemented by Evan Jones, and reworked by Tim Peters.)

Note that this change means extension modules must be more careful when allocating memory. Python’s API has many different functions for allocating memory that are grouped into families. For example, PyMem_Malloc(), PyMem_Realloc(), and PyMem_Free() are one family that allocates raw memory, while PyObject_Malloc(), PyObject_Realloc(), and PyObject_Free() are another family that’s supposed to be used for creating Python objects.

Previously these different families all reduced to the platform’s malloc() and free() functions. This meant it didn’t matter if you got things wrong and allocated memory with the PyMem function but freed it with the PyObject function. With 2.5’s changes to obmalloc, these families now do different things and mismatches will probably result in a segfault. You should carefully test your C extension modules with Python 2.5.

The built-in set types now have an official C API. Call PySet_New() and PyFrozenSet_New() to create a new set, PySet_Add() and PySet_Discard() to add and remove elements, and PySet_Contains() and PySet_Size() to examine the set’s state. (Contributed by Raymond Hettinger.)

C code can now obtain information about the exact revision of the Python interpreter by calling the Py_GetBuildInfo() function that returns a string of build information like this: "trunk:45355:45356M, Apr 13 2006, 07:42:19". (Contributed by Barry Warsaw.)

Two new macros can be used to indicate C functions that are local to the current file so that a faster calling convention can be used. Py_LOCAL(type) declares the function as returning a value of the specified type and uses a fast-calling qualifier. Py_LOCAL_INLINE(type) does the same thing and also requests the function be inlined. If macro PY_LOCAL_AGGRESSIVE is defined before python.h is included, a set of more aggressive optimizations are enabled for the module; you should benchmark the results to find out if these optimizations actually make the code faster. (Contributed by Fredrik Lundh at the NeedForSpeed sprint.)

PyErr_NewException(name, base, dict) can now accept a tuple of base classes as its base argument. (Contributed by Georg Brandl.)

The PyErr_Warn() function for issuing warnings is now deprecated in favour of PyErr_WarnEx(category, message, stacklevel) which lets you specify the number of stack frames separating this function and the caller. A stacklevel of 1 is the function calling PyErr_WarnEx(), 2 is the function above that, and so forth. (Added by Neal Norwitz.)

The CPython interpreter is still written in C, but the code can now be compiled with a C++ compiler without errors. (Implemented by Anthony Baxter, Martin von Löwis, Skip Montanaro.)

The PyRange_New() function was removed. It was never documented, never used in the core code, and had dangerously lax error checking. In the unlikely case that your extensions were using it, you can replace it by something like the following:

range = PyObject_CallFunction((PyObject*) &PyRange_Type, "lll",
                              start, stop, step);

Port-Specific Changes

MacOS X (10.3 and higher): dynamic loading of modules now uses the dlopen() function instead of MacOS-specific functions.

MacOS X: an --enable-universalsdk switch was added to the configure script that compiles the interpreter as a universal binary able to run on both PowerPC and Intel processors. (Contributed by Ronald Oussoren; bpo-2573 [https://bugs.python.org/issue?@action=redirect&bpo=2573].)

Windows: .dll is no longer supported as a filename extension for extension modules. .pyd is now the only filename extension that will be searched for.

Porting to Python 2.5

This section lists previously described changes that may require changes to your code:

ASCII is now the default encoding for modules. It’s now a syntax error if a module contains string literals with 8-bit characters but doesn’t have an encoding declaration. In Python 2.4 this triggered a warning, not a syntax error.

Previously, the gi_frame attribute of a generator was always a frame object. Because of the PEP 342 [https://peps.python.org/pep-0342/] changes described in section PEP 342: New Generator Features, it’s now possible for gi_frame to be None.

A new warning, UnicodeWarning, is triggered when you attempt to compare a Unicode string and an 8-bit string that can’t be converted to Unicode using the default ASCII encoding. Previously such comparisons would raise a UnicodeDecodeError exception.

Library: the csv module is now stricter about multi-line quoted fields. If your files contain newlines embedded within fields, the input should be split into lines in a manner which preserves the newline characters.

Library: the locale module’s format() function’s would previously accept any string as long as no more than one %char specifier appeared. In Python 2.5, the argument must be exactly one %char specifier with no surrounding text.

Library: The pickle and cPickle modules no longer accept a return value of None from the __reduce__() method; the method must return a tuple of arguments instead. The modules also no longer accept the deprecated bin keyword parameter.

Library: The SimpleXMLRPCServer and DocXMLRPCServer classes now have a rpc_paths attribute that constrains XML-RPC operations to a limited set of URL paths; the default is to allow only '/' and '/RPC2'. Setting rpc_paths to None or an empty tuple disables this path checking.

C API: Many functions now use Py_ssize_t instead of int to allow processing more data on 64-bit machines. Extension code may need to make the same change to avoid warnings and to support 64-bit machines. See the earlier section PEP 353: Using ssize_t as the index type for a discussion of this change.

C API: The obmalloc changes mean that you must be careful to not mix usage of the PyMem_* and PyObject_* families of functions. Memory allocated with one family’s *_Malloc must be freed with the corresponding family’s *_Free function.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Georg Brandl, Nick Coghlan, Phillip J. Eby, Lars Gustäbel, Raymond Hettinger, Ralf W. Grosse-Kunstleve, Kent Johnson, Iain Lowe, Martin von Löwis, Fredrik Lundh, Andrew McNamara, Skip Montanaro, Gustavo Niemeyer, Paul Prescod, James Pryor, Mike Rovner, Scott Weikart, Barry Warsaw, Thomas Wouters.

What’s New in Python 2.4

Author:

A.M. Kuchling

This article explains the new features in Python 2.4.1, released on March 30, 2005.

Python 2.4 is a medium-sized release. It doesn’t introduce as many changes as the radical Python 2.2, but introduces more features than the conservative 2.3 release. The most significant new language features are function decorators and generator expressions; most other changes are to the standard library.

According to the CVS change logs, there were 481 patches applied and 502 bugs fixed between Python 2.3 and 2.4. Both figures are likely to be underestimates.

This article doesn’t attempt to provide a complete specification of every single new feature, but instead provides a brief introduction to each feature. For full details, you should refer to the documentation for Python 2.4, such as the Python Library Reference and the Python Reference Manual. Often you will be referred to the PEP for a particular new feature for explanations of the implementation and design rationale.

PEP 218: Built-In Set Objects

Python 2.3 introduced the sets module. C implementations of set data types have now been added to the Python core as two new built-in types, set(iterable) and frozenset(iterable). They provide high speed operations for membership testing, for eliminating duplicates from sequences, and for mathematical operations like unions, intersections, differences, and symmetric differences.

>>> a = set('abracadabra')              # form a set from a string
>>> 'z' in a                            # fast membership testing
False
>>> a                                   # unique letters in a
set(['a', 'r', 'b', 'c', 'd'])
>>> ''.join(a)                          # convert back into a string
'arbcd'

>>> b = set('alacazam')                 # form a second set
>>> a - b                               # letters in a but not in b
set(['r', 'd', 'b'])
>>> a | b                               # letters in either a or b
set(['a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'])
>>> a & b                               # letters in both a and b
set(['a', 'c'])
>>> a ^ b                               # letters in a or b but not both
set(['r', 'd', 'b', 'm', 'z', 'l'])

>>> a.add('z')                          # add a new element
>>> a.update('wxy')                     # add multiple new elements
>>> a
set(['a', 'c', 'b', 'd', 'r', 'w', 'y', 'x', 'z'])
>>> a.remove('x')                       # take one element out
>>> a
set(['a', 'c', 'b', 'd', 'r', 'w', 'y', 'z'])

The frozenset() type is an immutable version of set(). Since it is immutable and hashable, it may be used as a dictionary key or as a member of another set.

The sets module remains in the standard library, and may be useful if you wish to subclass the Set or ImmutableSet classes. There are currently no plans to deprecate the module.

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PEP 218 [https://peps.python.org/pep-0218/] - Adding a Built-In Set Object Type

Originally proposed by Greg Wilson and ultimately implemented by Raymond Hettinger.

PEP 237: Unifying Long Integers and Integers

The lengthy transition process for this PEP, begun in Python 2.2, takes another step forward in Python 2.4. In 2.3, certain integer operations that would behave differently after int/long unification triggered FutureWarning warnings and returned values limited to 32 or 64 bits (depending on your platform). In 2.4, these expressions no longer produce a warning and instead produce a different result that’s usually a long integer.

The problematic expressions are primarily left shifts and lengthy hexadecimal and octal constants. For example, 2 << 32 results in a warning in 2.3, evaluating to 0 on 32-bit platforms. In Python 2.4, this expression now returns the correct answer, 8589934592.

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PEP 237 [https://peps.python.org/pep-0237/] - Unifying Long Integers and Integers

Original PEP written by Moshe Zadka and GvR. The changes for 2.4 were implemented by Kalle Svensson.

PEP 289: Generator Expressions

The iterator feature introduced in Python 2.2 and the itertools module make it easier to write programs that loop through large data sets without having the entire data set in memory at one time. List comprehensions don’t fit into this picture very well because they produce a Python list object containing all of the items. This unavoidably pulls all of the objects into memory, which can be a problem if your data set is very large. When trying to write a functionally styled program, it would be natural to write something like:

links = [link for link in get_all_links() if not link.followed]
for link in links:
    ...

instead of

for link in get_all_links():
    if link.followed:
        continue
    ...

The first form is more concise and perhaps more readable, but if you’re dealing with a large number of link objects you’d have to write the second form to avoid having all link objects in memory at the same time.

Generator expressions work similarly to list comprehensions but don’t materialize the entire list; instead they create a generator that will return elements one by one. The above example could be written as:

links = (link for link in get_all_links() if not link.followed)
for link in links:
    ...

Generator expressions always have to be written inside parentheses, as in the above example. The parentheses signalling a function call also count, so if you want to create an iterator that will be immediately passed to a function you could write:

print sum(obj.count for obj in list_all_objects())

Generator expressions differ from list comprehensions in various small ways. Most notably, the loop variable (obj in the above example) is not accessible outside of the generator expression. List comprehensions leave the variable assigned to its last value; future versions of Python will change this, making list comprehensions match generator expressions in this respect.

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PEP 289 [https://peps.python.org/pep-0289/] - Generator Expressions

Proposed by Raymond Hettinger and implemented by Jiwon Seo with early efforts steered by Hye-Shik Chang.

PEP 292: Simpler String Substitutions

Some new classes in the standard library provide an alternative mechanism for substituting variables into strings; this style of substitution may be better for applications where untrained users need to edit templates.

The usual way of substituting variables by name is the % operator:

>>> '%(page)i: %(title)s' % {'page':2, 'title': 'The Best of Times'}
'2: The Best of Times'

When writing the template string, it can be easy to forget the i or s after the closing parenthesis. This isn’t a big problem if the template is in a Python module, because you run the code, get an “Unsupported format character” ValueError, and fix the problem. However, consider an application such as Mailman where template strings or translations are being edited by users who aren’t aware of the Python language. The format string’s syntax is complicated to explain to such users, and if they make a mistake, it’s difficult to provide helpful feedback to them.

PEP 292 adds a Template class to the string module that uses $ to indicate a substitution:

>>> import string
>>> t = string.Template('$page: $title')
>>> t.substitute({'page':2, 'title': 'The Best of Times'})
'2: The Best of Times'

If a key is missing from the dictionary, the substitute() method will raise a KeyError. There’s also a safe_substitute() method that ignores missing keys:

>>> t = string.Template('$page: $title')
>>> t.safe_substitute({'page':3})
'3: $title'

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PEP 292 [https://peps.python.org/pep-0292/] - Simpler String Substitutions

Written and implemented by Barry Warsaw.

PEP 318: Decorators for Functions and Methods

Python 2.2 extended Python’s object model by adding static methods and class methods, but it didn’t extend Python’s syntax to provide any new way of defining static or class methods. Instead, you had to write a def statement in the usual way, and pass the resulting method to a staticmethod() or classmethod() function that would wrap up the function as a method of the new type. Your code would look like this:

class C:
   def meth (cls):
       ...

   meth = classmethod(meth)   # Rebind name to wrapped-up class method

If the method was very long, it would be easy to miss or forget the classmethod() invocation after the function body.

The intention was always to add some syntax to make such definitions more readable, but at the time of 2.2’s release a good syntax was not obvious. Today a good syntax still isn’t obvious but users are asking for easier access to the feature; a new syntactic feature has been added to meet this need.

The new feature is called “function decorators”. The name comes from the idea that classmethod(), staticmethod(), and friends are storing additional information on a function object; they’re decorating functions with more details.

The notation borrows from Java and uses the '@' character as an indicator. Using the new syntax, the example above would be written:

class C:

   @classmethod
   def meth (cls):
       ...

The @classmethod is shorthand for the meth=classmethod(meth) assignment. More generally, if you have the following:

@A
@B
@C
def f ():
    ...

It’s equivalent to the following pre-decorator code:

def f(): ...
f = A(B(C(f)))

Decorators must come on the line before a function definition, one decorator per line, and can’t be on the same line as the def statement, meaning that @A def f(): ... is illegal. You can only decorate function definitions, either at the module level or inside a class; you can’t decorate class definitions.

A decorator is just a function that takes the function to be decorated as an argument and returns either the same function or some new object. The return value of the decorator need not be callable (though it typically is), unless further decorators will be applied to the result. It’s easy to write your own decorators. The following simple example just sets an attribute on the function object:

>>> def deco(func):
...    func.attr = 'decorated'
...    return func
...
>>> @deco
... def f(): pass
...
>>> f
<function f at 0x402ef0d4>
>>> f.attr
'decorated'
>>>

As a slightly more realistic example, the following decorator checks that the supplied argument is an integer:

def require_int (func):
    def wrapper (arg):
        assert isinstance(arg, int)
        return func(arg)

    return wrapper

@require_int
def p1 (arg):
    print arg

@require_int
def p2(arg):
    print arg*2

An example in PEP 318 [https://peps.python.org/pep-0318/] contains a fancier version of this idea that lets you both specify the required type and check the returned type.

Decorator functions can take arguments. If arguments are supplied, your decorator function is called with only those arguments and must return a new decorator function; this function must take a single function and return a function, as previously described. In other words, @A @B @C(args) becomes:

def f(): ...
_deco = C(args)
f = A(B(_deco(f)))

Getting this right can be slightly brain-bending, but it’s not too difficult.

A small related change makes the func_name attribute of functions writable. This attribute is used to display function names in tracebacks, so decorators should change the name of any new function that’s constructed and returned.

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PEP 318 [https://peps.python.org/pep-0318/] - Decorators for Functions, Methods and Classes

Written by Kevin D. Smith, Jim Jewett, and Skip Montanaro. Several people wrote patches implementing function decorators, but the one that was actually checked in was patch #979728, written by Mark Russell.

https://wiki.python.org/moin/PythonDecoratorLibrary

This Wiki page contains several examples of decorators.

PEP 322: Reverse Iteration

A new built-in function, reversed(seq), takes a sequence and returns an iterator that loops over the elements of the sequence in reverse order.

>>> for i in reversed(xrange(1,4)):
...    print i
...
3
2
1

Compared to extended slicing, such as range(1,4)[::-1], reversed() is easier to read, runs faster, and uses substantially less memory.

Note that reversed() only accepts sequences, not arbitrary iterators. If you want to reverse an iterator, first convert it to a list with list().

>>> input = open('/etc/passwd', 'r')
>>> for line in reversed(list(input)):
...   print line
...
root:*:0:0:System Administrator:/var/root:/bin/tcsh
  ...

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PEP 322 [https://peps.python.org/pep-0322/] - Reverse Iteration

Written and implemented by Raymond Hettinger.

PEP 324: New subprocess Module

The standard library provides a number of ways to execute a subprocess, offering different features and different levels of complexity. os.system(command) is easy to use, but slow (it runs a shell process which executes the command) and dangerous (you have to be careful about escaping the shell’s metacharacters). The popen2 module offers classes that can capture standard output and standard error from the subprocess, but the naming is confusing. The subprocess module cleans this up, providing a unified interface that offers all the features you might need.

Instead of popen2’s collection of classes, subprocess contains a single class called subprocess.Popen whose constructor supports a number of different keyword arguments.

class Popen(args, bufsize=0, executable=None,
            stdin=None, stdout=None, stderr=None,
            preexec_fn=None, close_fds=False, shell=False,
            cwd=None, env=None, universal_newlines=False,
            startupinfo=None, creationflags=0):

args is commonly a sequence of strings that will be the arguments to the program executed as the subprocess. (If the shell argument is true, args can be a string which will then be passed on to the shell for interpretation, just as os.system() does.)

stdin, stdout, and stderr specify what the subprocess’s input, output, and error streams will be. You can provide a file object or a file descriptor, or you can use the constant subprocess.PIPE to create a pipe between the subprocess and the parent.

The constructor has a number of handy options:

close_fds requests that all file descriptors be closed before running the subprocess.

cwd specifies the working directory in which the subprocess will be executed (defaulting to whatever the parent’s working directory is).

env is a dictionary specifying environment variables.

preexec_fn is a function that gets called before the child is started.

universal_newlines opens the child’s input and output using Python’s universal newlines feature.

Once you’ve created the Popen instance, you can call its wait() method to pause until the subprocess has exited, poll() to check if it’s exited without pausing, or communicate(data) to send the string data to the subprocess’s standard input. communicate(data) then reads any data that the subprocess has sent to its standard output or standard error, returning a tuple (stdout_data, stderr_data).

call() is a shortcut that passes its arguments along to the Popen constructor, waits for the command to complete, and returns the status code of the subprocess. It can serve as a safer analog to os.system():

sts = subprocess.call(['dpkg', '-i', '/tmp/new-package.deb'])
if sts == 0:
    # Success
    ...
else:
    # dpkg returned an error
    ...

The command is invoked without use of the shell. If you really do want to use the shell, you can add shell=True as a keyword argument and provide a string instead of a sequence:

sts = subprocess.call('dpkg -i /tmp/new-package.deb', shell=True)

The PEP takes various examples of shell and Python code and shows how they’d be translated into Python code that uses subprocess. Reading this section of the PEP is highly recommended.

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PEP 324 [https://peps.python.org/pep-0324/] - subprocess - New process module

Written and implemented by Peter Åstrand, with assistance from Fredrik Lundh and others.

PEP 327: Decimal Data Type

Python has always supported floating-point (FP) numbers, based on the underlying C double type, as a data type. However, while most programming languages provide a floating-point type, many people (even programmers) are unaware that floating-point numbers don’t represent certain decimal fractions accurately. The new Decimal type can represent these fractions accurately, up to a user-specified precision limit.

Why is Decimal needed?

The limitations arise from the representation used for floating-point numbers. FP numbers are made up of three components:

The sign, which is positive or negative.

The mantissa, which is a single-digit binary number followed by a fractional part. For example, 1.01 in base-2 notation is 1 + 0/2 + 1/4, or 1.25 in decimal notation.

The exponent, which tells where the decimal point is located in the number represented.

For example, the number 1.25 has positive sign, a mantissa value of 1.01 (in binary), and an exponent of 0 (the decimal point doesn’t need to be shifted). The number 5 has the same sign and mantissa, but the exponent is 2 because the mantissa is multiplied by 4 (2 to the power of the exponent 2); 1.25 * 4 equals 5.

Modern systems usually provide floating-point support that conforms to a standard called IEEE 754. C’s double type is usually implemented as a 64-bit IEEE 754 number, which uses 52 bits of space for the mantissa. This means that numbers can only be specified to 52 bits of precision. If you’re trying to represent numbers whose expansion repeats endlessly, the expansion is cut off after 52 bits. Unfortunately, most software needs to produce output in base 10, and common fractions in base 10 are often repeating decimals in binary. For example, 1.1 decimal is binary 1.0001100110011 ...; .1 = 1/16 + 1/32 + 1/256 plus an infinite number of additional terms. IEEE 754 has to chop off that infinitely repeated decimal after 52 digits, so the representation is slightly inaccurate.

Sometimes you can see this inaccuracy when the number is printed:

>>> 1.1
1.1000000000000001

The inaccuracy isn’t always visible when you print the number because the FP-to-decimal-string conversion is provided by the C library, and most C libraries try to produce sensible output. Even if it’s not displayed, however, the inaccuracy is still there and subsequent operations can magnify the error.

For many applications this doesn’t matter. If I’m plotting points and displaying them on my monitor, the difference between 1.1 and 1.1000000000000001 is too small to be visible. Reports often limit output to a certain number of decimal places, and if you round the number to two or three or even eight decimal places, the error is never apparent. However, for applications where it does matter, it’s a lot of work to implement your own custom arithmetic routines.

Hence, the Decimal type was created.

The Decimal type

A new module, decimal, was added to Python’s standard library. It contains two classes, Decimal and Context. Decimal instances represent numbers, and Context instances are used to wrap up various settings such as the precision and default rounding mode.

Decimal instances are immutable, like regular Python integers and FP numbers; once it’s been created, you can’t change the value an instance represents. Decimal instances can be created from integers or strings:

>>> import decimal
>>> decimal.Decimal(1972)
Decimal("1972")
>>> decimal.Decimal("1.1")
Decimal("1.1")

You can also provide tuples containing the sign, the mantissa represented as a tuple of decimal digits, and the exponent:

>>> decimal.Decimal((1, (1, 4, 7, 5), -2))
Decimal("-14.75")

Cautionary note: the sign bit is a Boolean value, so 0 is positive and 1 is negative.

Converting from floating-point numbers poses a bit of a problem: should the FP number representing 1.1 turn into the decimal number for exactly 1.1, or for 1.1 plus whatever inaccuracies are introduced? The decision was to dodge the issue and leave such a conversion out of the API. Instead, you should convert the floating-point number into a string using the desired precision and pass the string to the Decimal constructor:

>>> f = 1.1
>>> decimal.Decimal(str(f))
Decimal("1.1")
>>> decimal.Decimal('%.12f' % f)
Decimal("1.100000000000")

Once you have Decimal instances, you can perform the usual mathematical operations on them. One limitation: exponentiation requires an integer exponent:

>>> a = decimal.Decimal('35.72')
>>> b = decimal.Decimal('1.73')
>>> a+b
Decimal("37.45")
>>> a-b
Decimal("33.99")
>>> a*b
Decimal("61.7956")
>>> a/b
Decimal("20.64739884393063583815028902")
>>> a ** 2
Decimal("1275.9184")
>>> a**b
Traceback (most recent call last):
  ...
decimal.InvalidOperation: x ** (non-integer)

You can combine Decimal instances with integers, but not with floating-point numbers:

>>> a + 4
Decimal("39.72")
>>> a + 4.5
Traceback (most recent call last):
  ...
TypeError: You can interact Decimal only with int, long or Decimal data types.
>>>

Decimal numbers can be used with the math and cmath modules, but note that they’ll be immediately converted to floating-point numbers before the operation is performed, resulting in a possible loss of precision and accuracy. You’ll also get back a regular floating-point number and not a Decimal.

>>> import math, cmath
>>> d = decimal.Decimal('123456789012.345')
>>> math.sqrt(d)
351364.18288201344
>>> cmath.sqrt(-d)
351364.18288201344j

Decimal instances have a sqrt() method that returns a Decimal, but if you need other things such as trigonometric functions you’ll have to implement them.

>>> d.sqrt()
Decimal("351364.1828820134592177245001")

The Context type

Instances of the Context class encapsulate several settings for decimal operations:

prec is the precision, the number of decimal places.

rounding specifies the rounding mode. The decimal module has constants for the various possibilities: ROUND_DOWN, ROUND_CEILING, ROUND_HALF_EVEN, and various others.

traps is a dictionary specifying what happens on encountering certain error conditions: either an exception is raised or a value is returned. Some examples of error conditions are division by zero, loss of precision, and overflow.

There’s a thread-local default context available by calling getcontext(); you can change the properties of this context to alter the default precision, rounding, or trap handling. The following example shows the effect of changing the precision of the default context:

>>> decimal.getcontext().prec
28
>>> decimal.Decimal(1) / decimal.Decimal(7)
Decimal("0.1428571428571428571428571429")
>>> decimal.getcontext().prec = 9
>>> decimal.Decimal(1) / decimal.Decimal(7)
Decimal("0.142857143")

The default action for error conditions is selectable; the module can either return a special value such as infinity or not-a-number, or exceptions can be raised:

>>> decimal.Decimal(1) / decimal.Decimal(0)
Traceback (most recent call last):
  ...
decimal.DivisionByZero: x / 0
>>> decimal.getcontext().traps[decimal.DivisionByZero] = False
>>> decimal.Decimal(1) / decimal.Decimal(0)
Decimal("Infinity")
>>>

The Context instance also has various methods for formatting numbers such as to_eng_string() and to_sci_string().

For more information, see the documentation for the decimal module, which includes a quick-start tutorial and a reference.

더 보기

PEP 327 [https://peps.python.org/pep-0327/] - Decimal Data Type

Written by Facundo Batista and implemented by Facundo Batista, Eric Price, Raymond Hettinger, Aahz, and Tim Peters.

http://www.lahey.com/float.htm [https://web.archive.org/web/20230604072523/http://www.lahey.com/float.htm]

The article uses Fortran code to illustrate many of the problems that floating-point inaccuracy can cause.

https://speleotrove.com/decimal/

A description of a decimal-based representation. This representation is being proposed as a standard, and underlies the new Python decimal type. Much of this material was written by Mike Cowlishaw, designer of the Rexx language.

PEP 328: Multi-line Imports

One language change is a small syntactic tweak aimed at making it easier to import many names from a module. In a from module import names statement, names is a sequence of names separated by commas. If the sequence is very long, you can either write multiple imports from the same module, or you can use backslashes to escape the line endings like this:

from SimpleXMLRPCServer import SimpleXMLRPCServer,\
            SimpleXMLRPCRequestHandler,\
            CGIXMLRPCRequestHandler,\
            resolve_dotted_attribute

The syntactic change in Python 2.4 simply allows putting the names within parentheses. Python ignores newlines within a parenthesized expression, so the backslashes are no longer needed:

from SimpleXMLRPCServer import (SimpleXMLRPCServer,
                                SimpleXMLRPCRequestHandler,
                                CGIXMLRPCRequestHandler,
                                resolve_dotted_attribute)

The PEP also proposes that all import statements be absolute imports, with a leading . character to indicate a relative import. This part of the PEP was not implemented for Python 2.4, but was completed for Python 2.5.

더 보기

PEP 328 [https://peps.python.org/pep-0328/] - Imports: Multi-Line and Absolute/Relative

Written by Aahz. Multi-line imports were implemented by Dima Dorfman.

PEP 331: Locale-Independent Float/String Conversions

The locale modules lets Python software select various conversions and display conventions that are localized to a particular country or language. However, the module was careful to not change the numeric locale because various functions in Python’s implementation required that the numeric locale remain set to the 'C' locale. Often this was because the code was using the C library’s atof() function.

Not setting the numeric locale caused trouble for extensions that used third-party C libraries, however, because they wouldn’t have the correct locale set. The motivating example was GTK+, whose user interface widgets weren’t displaying numbers in the current locale.

The solution described in the PEP is to add three new functions to the Python API that perform ASCII-only conversions, ignoring the locale setting:

PyOS_ascii_strtod(str, ptr) and PyOS_ascii_atof(str, ptr) both convert a string to a C double.

PyOS_ascii_formatd(buffer, buf_len, format, d) converts a double to an ASCII string.

The code for these functions came from the GLib library (https://developer-old.gnome.org/glib/2.26/ [http://web.archive.org/web/20210306104320/https://developer.gnome.org/glib/2.26/]), whose developers kindly relicensed the relevant functions and donated them to the Python Software Foundation. The locale module can now change the numeric locale, letting extensions such as GTK+ produce the correct results.

더 보기

PEP 331 [https://peps.python.org/pep-0331/] - Locale-Independent Float/String Conversions

Written by Christian R. Reis, and implemented by Gustavo Carneiro.

Other Language Changes

Here are all of the changes that Python 2.4 makes to the core Python language.

Decorators for functions and methods were added (PEP 318 [https://peps.python.org/pep-0318/]).

Built-in set() and frozenset() types were added (PEP 218 [https://peps.python.org/pep-0218/]). Other new built-ins include the reversed(seq) function (PEP 322 [https://peps.python.org/pep-0322/]).

Generator expressions were added (PEP 289 [https://peps.python.org/pep-0289/]).

Certain numeric expressions no longer return values restricted to 32 or 64 bits (PEP 237 [https://peps.python.org/pep-0237/]).

You can now put parentheses around the list of names in a from module import names statement (PEP 328 [https://peps.python.org/pep-0328/]).

The dict.update() method now accepts the same argument forms as the dict constructor. This includes any mapping, any iterable of key/value pairs, and keyword arguments. (Contributed by Raymond Hettinger.)

The string methods ljust(), rjust(), and center() now take an optional argument for specifying a fill character other than a space. (Contributed by Raymond Hettinger.)

Strings also gained an rsplit() method that works like the split() method but splits from the end of the string. (Contributed by Sean Reifschneider.)

>>> 'www.python.org'.split('.', 1)
['www', 'python.org']
'www.python.org'.rsplit('.', 1)
['www.python', 'org']

Three keyword parameters, cmp, key, and reverse, were added to the sort() method of lists. These parameters make some common usages of sort() simpler. All of these parameters are optional.

For the cmp parameter, the value should be a comparison function that takes two parameters and returns -1, 0, or +1 depending on how the parameters compare. This function will then be used to sort the list. Previously this was the only parameter that could be provided to sort().

key should be a single-parameter function that takes a list element and returns a comparison key for the element. The list is then sorted using the comparison keys. The following example sorts a list case-insensitively:

>>> L = ['A', 'b', 'c', 'D']
>>> L.sort()                 # Case-sensitive sort
>>> L
['A', 'D', 'b', 'c']
>>> # Using 'key' parameter to sort list
>>> L.sort(key=lambda x: x.lower())
>>> L
['A', 'b', 'c', 'D']
>>> # Old-fashioned way
>>> L.sort(cmp=lambda x,y: cmp(x.lower(), y.lower()))
>>> L
['A', 'b', 'c', 'D']

The last example, which uses the cmp parameter, is the old way to perform a case-insensitive sort. It works but is slower than using a key parameter. Using key calls lower() method once for each element in the list while using cmp will call it twice for each comparison, so using key saves on invocations of the lower() method.

For simple key functions and comparison functions, it is often possible to avoid a lambda expression by using an unbound method instead. For example, the above case-insensitive sort is best written as:

>>> L.sort(key=str.lower)
>>> L
['A', 'b', 'c', 'D']

Finally, the reverse parameter takes a Boolean value. If the value is true, the list will be sorted into reverse order. Instead of L.sort(); L.reverse(), you can now write L.sort(reverse=True).

The results of sorting are now guaranteed to be stable. This means that two entries with equal keys will be returned in the same order as they were input. For example, you can sort a list of people by name, and then sort the list by age, resulting in a list sorted by age where people with the same age are in name-sorted order.

(All changes to sort() contributed by Raymond Hettinger.)

There is a new built-in function sorted(iterable) that works like the in-place list.sort() method but can be used in expressions. The differences are:

the input may be any iterable;

a newly formed copy is sorted, leaving the original intact; and

the expression returns the new sorted copy

>>> L = [9,7,8,3,2,4,1,6,5]
>>> [10+i for i in sorted(L)]       # usable in a list comprehension
[11, 12, 13, 14, 15, 16, 17, 18, 19]
>>> L                               # original is left unchanged
[9,7,8,3,2,4,1,6,5]
>>> sorted('Monty Python')          # any iterable may be an input
[' ', 'M', 'P', 'h', 'n', 'n', 'o', 'o', 't', 't', 'y', 'y']

>>> # List the contents of a dict sorted by key values
>>> colormap = dict(red=1, blue=2, green=3, black=4, yellow=5)
>>> for k, v in sorted(colormap.iteritems()):
...     print k, v
...
black 4
blue 2
green 3
red 1
yellow 5

(Contributed by Raymond Hettinger.)

Integer operations will no longer trigger an OverflowWarning. The OverflowWarning warning will disappear in Python 2.5.

The interpreter gained a new switch, -m, that takes a name, searches for the corresponding module on sys.path, and runs the module as a script. For example, you can now run the Python profiler with python -m profile. (Contributed by Nick Coghlan.)

The eval(expr, globals, locals) and execfile(filename, globals, locals) functions and the exec statement now accept any mapping type for the locals parameter. Previously this had to be a regular Python dictionary. (Contributed by Raymond Hettinger.)

The zip() built-in function and itertools.izip() now return an empty list if called with no arguments. Previously they raised a TypeError exception. This makes them more suitable for use with variable length argument lists:

>>> def transpose(array):
...    return zip(*array)
...
>>> transpose([(1,2,3), (4,5,6)])
[(1, 4), (2, 5), (3, 6)]
>>> transpose([])
[]

(Contributed by Raymond Hettinger.)

Encountering a failure while importing a module no longer leaves a partially initialized module object in sys.modules. The incomplete module object left behind would fool further imports of the same module into succeeding, leading to confusing errors. (Fixed by Tim Peters.)

None is now a constant; code that binds a new value to the name None is now a syntax error. (Contributed by Raymond Hettinger.)

Optimizations

The inner loops for list and tuple slicing were optimized and now run about one-third faster. The inner loops for dictionaries were also optimized, resulting in performance boosts for keys(), values(), items(), iterkeys(), itervalues(), and iteritems(). (Contributed by Raymond Hettinger.)

The machinery for growing and shrinking lists was optimized for speed and for space efficiency. Appending and popping from lists now runs faster due to more efficient code paths and less frequent use of the underlying system realloc(). List comprehensions also benefit. list.extend() was also optimized and no longer converts its argument into a temporary list before extending the base list. (Contributed by Raymond Hettinger.)

list(), tuple(), map(), filter(), and zip() now run several times faster with non-sequence arguments that supply a __len__() method. (Contributed by Raymond Hettinger.)

The methods list.__getitem__(), dict.__getitem__(), and dict.__contains__() are now implemented as method_descriptor objects rather than wrapper_descriptor objects. This form of access doubles their performance and makes them more suitable for use as arguments to functionals: map(mydict.__getitem__, keylist). (Contributed by Raymond Hettinger.)

Added a new opcode, LIST_APPEND, that simplifies the generated bytecode for list comprehensions and speeds them up by about a third. (Contributed by Raymond Hettinger.)

The peephole bytecode optimizer has been improved to produce shorter, faster bytecode; remarkably, the resulting bytecode is more readable. (Enhanced by Raymond Hettinger.)

String concatenations in statements of the form s = s + "abc" and s += "abc" are now performed more efficiently in certain circumstances. This optimization won’t be present in other Python implementations such as Jython, so you shouldn’t rely on it; using the join() method of strings is still recommended when you want to efficiently glue a large number of strings together. (Contributed by Armin Rigo.)

The net result of the 2.4 optimizations is that Python 2.4 runs the pystone benchmark around 5% faster than Python 2.3 and 35% faster than Python 2.2. (pystone is not a particularly good benchmark, but it’s the most commonly used measurement of Python’s performance. Your own applications may show greater or smaller benefits from Python 2.4.)

New, Improved, and Deprecated Modules

As usual, Python’s standard library received a number of enhancements and bug fixes. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the Misc/NEWS file in the source tree for a more complete list of changes, or look through the CVS logs for all the details.

The asyncore module’s loop() function now has a count parameter that lets you perform a limited number of passes through the polling loop. The default is still to loop forever.

The base64 module now has more complete RFC 3548 [https://datatracker.ietf.org/doc/html/rfc3548.html] support for Base64, Base32, and Base16 encoding and decoding, including optional case folding and optional alternative alphabets. (Contributed by Barry Warsaw.)

The bisect module now has an underlying C implementation for improved performance. (Contributed by Dmitry Vasiliev.)

The CJKCodecs collections of East Asian codecs, maintained by Hye-Shik Chang, was integrated into 2.4. The new encodings are:

Chinese (PRC): gb2312, gbk, gb18030, big5hkscs, hz

Chinese (ROC): big5, cp950

Japanese: cp932, euc-jis-2004, euc-jp, euc-jisx0213, iso-2022-jp,

iso-2022-jp-1, iso-2022-jp-2, iso-2022-jp-3, iso-2022-jp-ext, iso-2022-jp-2004, shift-jis, shift-jisx0213, shift-jis-2004

Korean: cp949, euc-kr, johab, iso-2022-kr

Some other new encodings were added: HP Roman8, ISO_8859-11, ISO_8859-16, PCTP-154, and TIS-620.

The UTF-8 and UTF-16 codecs now cope better with receiving partial input. Previously the StreamReader class would try to read more data, making it impossible to resume decoding from the stream. The read() method will now return as much data as it can and future calls will resume decoding where previous ones left off. (Implemented by Walter Dörwald.)

There is a new collections module for various specialized collection datatypes. Currently it contains just one type, deque, a double-ended queue that supports efficiently adding and removing elements from either end:

>>> from collections import deque
>>> d = deque('ghi')        # make a new deque with three items
>>> d.append('j')           # add a new entry to the right side
>>> d.appendleft('f')       # add a new entry to the left side
>>> d                       # show the representation of the deque
deque(['f', 'g', 'h', 'i', 'j'])
>>> d.pop()                 # return and remove the rightmost item
'j'
>>> d.popleft()             # return and remove the leftmost item
'f'
>>> list(d)                 # list the contents of the deque
['g', 'h', 'i']
>>> 'h' in d                # search the deque
True

Several modules, such as the Queue and threading modules, now take advantage of collections.deque for improved performance. (Contributed by Raymond Hettinger.)

The ConfigParser classes have been enhanced slightly. The read() method now returns a list of the files that were successfully parsed, and the set() method raises TypeError if passed a value argument that isn’t a string. (Contributed by John Belmonte and David Goodger.)

The curses module now supports the ncurses extension use_default_colors(). On platforms where the terminal supports transparency, this makes it possible to use a transparent background. (Contributed by Jörg Lehmann.)

The difflib module now includes an HtmlDiff class that creates an HTML table showing a side by side comparison of two versions of a text. (Contributed by Dan Gass.)

The email package was updated to version 3.0, which dropped various deprecated APIs and removes support for Python versions earlier than 2.3. The 3.0 version of the package uses a new incremental parser for MIME messages, available in the email.FeedParser module. The new parser doesn’t require reading the entire message into memory, and doesn’t raise exceptions if a message is malformed; instead it records any problems in the defect attribute of the message. (Developed by Anthony Baxter, Barry Warsaw, Thomas Wouters, and others.)

The heapq module has been converted to C. The resulting tenfold improvement in speed makes the module suitable for handling high volumes of data. In addition, the module has two new functions nlargest() and nsmallest() that use heaps to find the N largest or smallest values in a dataset without the expense of a full sort. (Contributed by Raymond Hettinger.)

The httplib module now contains constants for HTTP status codes defined in various HTTP-related RFC documents. Constants have names such as OK, CREATED, CONTINUE, and MOVED_PERMANENTLY; use pydoc to get a full list. (Contributed by Andrew Eland.)

The imaplib module now supports IMAP’s THREAD command (contributed by Yves Dionne) and new deleteacl() and myrights() methods (contributed by Arnaud Mazin).

The itertools module gained a groupby(iterable[, *func*]) function. iterable is something that can be iterated over to return a stream of elements, and the optional func parameter is a function that takes an element and returns a key value; if omitted, the key is simply the element itself. groupby() then groups the elements into subsequences which have matching values of the key, and returns a series of 2-tuples containing the key value and an iterator over the subsequence.

Here’s an example to make this clearer. The key function simply returns whether a number is even or odd, so the result of groupby() is to return consecutive runs of odd or even numbers.

>>> import itertools
>>> L = [2, 4, 6, 7, 8, 9, 11, 12, 14]
>>> for key_val, it in itertools.groupby(L, lambda x: x % 2):
...    print key_val, list(it)
...
0 [2, 4, 6]
1 [7]
0 [8]
1 [9, 11]
0 [12, 14]
>>>

groupby() is typically used with sorted input. The logic for groupby() is similar to the Unix uniq filter which makes it handy for eliminating, counting, or identifying duplicate elements:

>>> word = 'abracadabra'
>>> letters = sorted(word)   # Turn string into a sorted list of letters
>>> letters
['a', 'a', 'a', 'a', 'a', 'b', 'b', 'c', 'd', 'r', 'r']
>>> for k, g in itertools.groupby(letters):
...    print k, list(g)
...
a ['a', 'a', 'a', 'a', 'a']
b ['b', 'b']
c ['c']
d ['d']
r ['r', 'r']
>>> # List unique letters
>>> [k for k, g in groupby(letters)]
['a', 'b', 'c', 'd', 'r']
>>> # Count letter occurrences
>>> [(k, len(list(g))) for k, g in groupby(letters)]
[('a', 5), ('b', 2), ('c', 1), ('d', 1), ('r', 2)]

(Contributed by Hye-Shik Chang.)

itertools also gained a function named tee(iterator, N) that returns N independent iterators that replicate iterator. If N is omitted, the default is 2.

>>> L = [1,2,3]
>>> i1, i2 = itertools.tee(L)
>>> i1,i2
(<itertools.tee object at 0x402c2080>, <itertools.tee object at 0x402c2090>)
>>> list(i1)               # Run the first iterator to exhaustion
[1, 2, 3]
>>> list(i2)               # Run the second iterator to exhaustion
[1, 2, 3]

Note that tee() has to keep copies of the values returned by the iterator; in the worst case, it may need to keep all of them. This should therefore be used carefully if the leading iterator can run far ahead of the trailing iterator in a long stream of inputs. If the separation is large, then you might as well use list() instead. When the iterators track closely with one another, tee() is ideal. Possible applications include bookmarking, windowing, or lookahead iterators. (Contributed by Raymond Hettinger.)

A number of functions were added to the locale module, such as bind_textdomain_codeset() to specify a particular encoding and a family of l*gettext() functions that return messages in the chosen encoding. (Contributed by Gustavo Niemeyer.)

Some keyword arguments were added to the logging package’s basicConfig() function to simplify log configuration. The default behavior is to log messages to standard error, but various keyword arguments can be specified to log to a particular file, change the logging format, or set the logging level. For example:

import logging
logging.basicConfig(filename='/var/log/application.log',
    level=0,  # Log all messages
    format='%(levelname):%(process):%(thread):%(message)')

Other additions to the logging package include a log(level, msg) convenience method, as well as a TimedRotatingFileHandler class that rotates its log files at a timed interval. The module already had RotatingFileHandler, which rotated logs once the file exceeded a certain size. Both classes derive from a new BaseRotatingHandler class that can be used to implement other rotating handlers.

(Changes implemented by Vinay Sajip.)

The marshal module now shares interned strings on unpacking a data structure. This may shrink the size of certain pickle strings, but the primary effect is to make .pyc files significantly smaller. (Contributed by Martin von Löwis.)

The nntplib module’s NNTP class gained description() and descriptions() methods to retrieve newsgroup descriptions for a single group or for a range of groups. (Contributed by Jürgen A. Erhard.)

Two new functions were added to the operator module, attrgetter(attr) and itemgetter(index). Both functions return callables that take a single argument and return the corresponding attribute or item; these callables make excellent data extractors when used with map() or sorted(). For example:

>>> L = [('c', 2), ('d', 1), ('a', 4), ('b', 3)]
>>> map(operator.itemgetter(0), L)
['c', 'd', 'a', 'b']
>>> map(operator.itemgetter(1), L)
[2, 1, 4, 3]
>>> sorted(L, key=operator.itemgetter(1)) # Sort list by second tuple item
[('d', 1), ('c', 2), ('b', 3), ('a', 4)]

(Contributed by Raymond Hettinger.)

The optparse module was updated in various ways. The module now passes its messages through gettext.gettext(), making it possible to internationalize Optik’s help and error messages. Help messages for options can now include the string '%default', which will be replaced by the option’s default value. (Contributed by Greg Ward.)

The long-term plan is to deprecate the rfc822 module in some future Python release in favor of the email package. To this end, the email.Utils.formatdate function has been changed to make it usable as a replacement for rfc822.formatdate(). You may want to write new e-mail processing code with this in mind. (Change implemented by Anthony Baxter.)

A new urandom(n) function was added to the os module, returning a string containing n bytes of random data. This function provides access to platform-specific sources of randomness such as /dev/urandom on Linux or the Windows CryptoAPI. (Contributed by Trevor Perrin.)

Another new function: os.path.lexists(path) returns true if the file specified by path exists, whether or not it’s a symbolic link. This differs from the existing os.path.exists(path) function, which returns false if path is a symlink that points to a destination that doesn’t exist. (Contributed by Beni Cherniavsky.)

A new getsid() function was added to the posix module that underlies the os module. (Contributed by J. Raynor.)

The poplib module now supports POP over SSL. (Contributed by Hector Urtubia.)

The profile module can now profile C extension functions. (Contributed by Nick Bastin.)

The random module has a new method called getrandbits(N) that returns a long integer N bits in length. The existing randrange() method now uses getrandbits() where appropriate, making generation of arbitrarily large random numbers more efficient. (Contributed by Raymond Hettinger.)

The regular expression language accepted by the re module was extended with simple conditional expressions, written as (?(group)A|B). group is either a numeric group ID or a group name defined with (?P<group>...) earlier in the expression. If the specified group matched, the regular expression pattern A will be tested against the string; if the group didn’t match, the pattern B will be used instead. (Contributed by Gustavo Niemeyer.)

The re module is also no longer recursive, thanks to a massive amount of work by Gustavo Niemeyer. In a recursive regular expression engine, certain patterns result in a large amount of C stack space being consumed, and it was possible to overflow the stack. For example, if you matched a 30000-byte string of a characters against the expression (a|b)+, one stack frame was consumed per character. Python 2.3 tried to check for stack overflow and raise a RuntimeError exception, but certain patterns could sidestep the checking and if you were unlucky Python could segfault. Python 2.4’s regular expression engine can match this pattern without problems.

The signal module now performs tighter error-checking on the parameters to the signal.signal() function. For example, you can’t set a handler on the SIGKILL signal; previous versions of Python would quietly accept this, but 2.4 will raise a RuntimeError exception.

Two new functions were added to the socket module. socketpair() returns a pair of connected sockets and getservbyport(port) looks up the service name for a given port number. (Contributed by Dave Cole and Barry Warsaw.)

The sys.exitfunc() function has been deprecated. Code should be using the existing atexit module, which correctly handles calling multiple exit functions. Eventually sys.exitfunc() will become a purely internal interface, accessed only by atexit.

The tarfile module now generates GNU-format tar files by default. (Contributed by Lars Gustäbel.)

The threading module now has an elegantly simple way to support thread-local data. The module contains a local class whose attribute values are local to different threads.

import threading

data = threading.local()
data.number = 42
data.url = ('www.python.org', 80)

Other threads can assign and retrieve their own values for the number and url attributes. You can subclass local to initialize attributes or to add methods. (Contributed by Jim Fulton.)

The timeit module now automatically disables periodic garbage collection during the timing loop. This change makes consecutive timings more comparable. (Contributed by Raymond Hettinger.)

The weakref module now supports a wider variety of objects including Python functions, class instances, sets, frozensets, deques, arrays, files, sockets, and regular expression pattern objects. (Contributed by Raymond Hettinger.)

The xmlrpclib module now supports a multi-call extension for transmitting multiple XML-RPC calls in a single HTTP operation. (Contributed by Brian Quinlan.)

The mpz, rotor, and xreadlines modules have been removed.

cookielib

The cookielib library supports client-side handling for HTTP cookies, mirroring the Cookie module’s server-side cookie support. Cookies are stored in cookie jars; the library transparently stores cookies offered by the web server in the cookie jar, and fetches the cookie from the jar when connecting to the server. As in web browsers, policy objects control whether cookies are accepted or not.

In order to store cookies across sessions, two implementations of cookie jars are provided: one that stores cookies in the Netscape format so applications can use the Mozilla or Lynx cookie files, and one that stores cookies in the same format as the Perl libwww library.

urllib2 has been changed to interact with cookielib: HTTPCookieProcessor manages a cookie jar that is used when accessing URLs.

This module was contributed by John J. Lee.

doctest

The doctest module underwent considerable refactoring thanks to Edward Loper and Tim Peters. Testing can still be as simple as running doctest.testmod(), but the refactorings allow customizing the module’s operation in various ways

The new DocTestFinder class extracts the tests from a given object’s docstrings:

def f (x, y):
    """>>> f(2,2)
4
>>> f(3,2)
6
    """
    return x*y

finder = doctest.DocTestFinder()

# Get list of DocTest instances
tests = finder.find(f)

The new DocTestRunner class then runs individual tests and can produce a summary of the results:

runner = doctest.DocTestRunner()
for t in tests:
    tried, failed = runner.run(t)

runner.summarize(verbose=1)

The above example produces the following output:

1 items passed all tests:
   2 tests in f
2 tests in 1 items.
2 passed and 0 failed.
Test passed.

DocTestRunner uses an instance of the OutputChecker class to compare the expected output with the actual output. This class takes a number of different flags that customize its behaviour; ambitious users can also write a completely new subclass of OutputChecker.

The default output checker provides a number of handy features. For example, with the doctest.ELLIPSIS option flag, an ellipsis (...) in the expected output matches any substring, making it easier to accommodate outputs that vary in minor ways:

def o (n):
    """>>> o(1)
<__main__.C instance at 0x...>
>>>
"""

Another special string, <BLANKLINE>, matches a blank line:

def p (n):
    """>>> p(1)
<BLANKLINE>
>>>
"""

Another new capability is producing a diff-style display of the output by specifying the doctest.REPORT_UDIFF (unified diffs), doctest.REPORT_CDIFF (context diffs), or doctest.REPORT_NDIFF (delta-style) option flags. For example:

def g (n):
    """>>> g(4)
here
is
a
lengthy
>>>"""
    L = 'here is a rather lengthy list of words'.split()
    for word in L[:n]:
        print word

Running the above function’s tests with doctest.REPORT_UDIFF specified, you get the following output:

**********************************************************************
File "t.py", line 15, in g
Failed example:
    g(4)
Differences (unified diff with -expected +actual):
    @@ -2,3 +2,3 @@
     is
     a
    -lengthy
    +rather
**********************************************************************

Build and C API Changes

Some of the changes to Python’s build process and to the C API are:

Three new convenience macros were added for common return values from extension functions: Py_RETURN_NONE, Py_RETURN_TRUE, and Py_RETURN_FALSE. (Contributed by Brett Cannon.)

Another new macro, Py_CLEAR, decreases the reference count of obj and sets obj to the null pointer. (Contributed by Jim Fulton.)

A new function, PyTuple_Pack(N, obj1, obj2, ..., objN), constructs tuples from a variable length argument list of Python objects. (Contributed by Raymond Hettinger.)

A new function, PyDict_Contains(d, k), implements fast dictionary lookups without masking exceptions raised during the look-up process. (Contributed by Raymond Hettinger.)

The Py_IS_NAN(X) macro returns 1 if its float or double argument X is a NaN. (Contributed by Tim Peters.)

C code can avoid unnecessary locking by using the new PyEval_ThreadsInitialized() function to tell if any thread operations have been performed. If this function returns false, no lock operations are needed. (Contributed by Nick Coghlan.)

A new function, PyArg_VaParseTupleAndKeywords(), is the same as PyArg_ParseTupleAndKeywords() but takes a va_list instead of a number of arguments. (Contributed by Greg Chapman.)

A new method flag, METH_COEXIST, allows a function defined in slots to co-exist with a PyCFunction having the same name. This can halve the access time for a method such as set.__contains__(). (Contributed by Raymond Hettinger.)

Python can now be built with additional profiling for the interpreter itself, intended as an aid to people developing the Python core. Providing --enable-profiling to the configure script will let you profile the interpreter with gprof, and providing the --with-tsc switch enables profiling using the Pentium’s Time-Stamp-Counter register. Note that the --with-tsc switch is slightly misnamed, because the profiling feature also works on the PowerPC platform, though that processor architecture doesn’t call that register “the TSC register”. (Contributed by Jeremy Hylton.)

The tracebackobject type has been renamed to PyTracebackObject.

Port-Specific Changes

The Windows port now builds under MSVC++ 7.1 as well as version 6. (Contributed by Martin von Löwis.)

Porting to Python 2.4

This section lists previously described changes that may require changes to your code:

Left shifts and hexadecimal/octal constants that are too large no longer trigger a FutureWarning and return a value limited to 32 or 64 bits; instead they return a long integer.

Integer operations will no longer trigger an OverflowWarning. The OverflowWarning warning will disappear in Python 2.5.

The zip() built-in function and itertools.izip() now return an empty list instead of raising a TypeError exception if called with no arguments.

You can no longer compare the date and datetime instances provided by the datetime module. Two instances of different classes will now always be unequal, and relative comparisons (<, >) will raise a TypeError.

dircache.listdir() now passes exceptions to the caller instead of returning empty lists.

LexicalHandler.startDTD() used to receive the public and system IDs in the wrong order. This has been corrected; applications relying on the wrong order need to be fixed.

fcntl.ioctl() now warns if the mutate argument is omitted and relevant.

The tarfile module now generates GNU-format tar files by default.

Encountering a failure while importing a module no longer leaves a partially initialized module object in sys.modules.

None is now a constant; code that binds a new value to the name None is now a syntax error.

The signals.signal() function now raises a RuntimeError exception for certain illegal values; previously these errors would pass silently. For example, you can no longer set a handler on the SIGKILL signal.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Koray Can, Hye-Shik Chang, Michael Dyck, Raymond Hettinger, Brian Hurt, Hamish Lawson, Fredrik Lundh, Sean Reifschneider, Sadruddin Rejeb.

What’s New in Python 2.3

Author:

A.M. Kuchling

This article explains the new features in Python 2.3. Python 2.3 was released on July 29, 2003.

The main themes for Python 2.3 are polishing some of the features added in 2.2, adding various small but useful enhancements to the core language, and expanding the standard library. The new object model introduced in the previous version has benefited from 18 months of bugfixes and from optimization efforts that have improved the performance of new-style classes. A few new built-in functions have been added such as sum() and enumerate(). The in operator can now be used for substring searches (e.g. "ab" in "abc" returns True).

Some of the many new library features include Boolean, set, heap, and date/time data types, the ability to import modules from ZIP-format archives, metadata support for the long-awaited Python catalog, an updated version of IDLE, and modules for logging messages, wrapping text, parsing CSV files, processing command-line options, using BerkeleyDB databases… the list of new and enhanced modules is lengthy.

This article doesn’t attempt to provide a complete specification of the new features, but instead provides a convenient overview. For full details, you should refer to the documentation for Python 2.3, such as the Python Library Reference and the Python Reference Manual. If you want to understand the complete implementation and design rationale, refer to the PEP for a particular new feature.

PEP 218: A Standard Set Datatype

The new sets module contains an implementation of a set datatype. The Set class is for mutable sets, sets that can have members added and removed. The ImmutableSet class is for sets that can’t be modified, and instances of ImmutableSet can therefore be used as dictionary keys. Sets are built on top of dictionaries, so the elements within a set must be hashable.

Here’s a simple example:

>>> import sets
>>> S = sets.Set([1,2,3])
>>> S
Set([1, 2, 3])
>>> 1 in S
True
>>> 0 in S
False
>>> S.add(5)
>>> S.remove(3)
>>> S
Set([1, 2, 5])
>>>

The union and intersection of sets can be computed with the union() and intersection() methods; an alternative notation uses the bitwise operators & and |. Mutable sets also have in-place versions of these methods, union_update() and intersection_update().

>>> S1 = sets.Set([1,2,3])
>>> S2 = sets.Set([4,5,6])
>>> S1.union(S2)
Set([1, 2, 3, 4, 5, 6])
>>> S1 | S2                  # Alternative notation
Set([1, 2, 3, 4, 5, 6])
>>> S1.intersection(S2)
Set([])
>>> S1 & S2                  # Alternative notation
Set([])
>>> S1.union_update(S2)
>>> S1
Set([1, 2, 3, 4, 5, 6])
>>>

It’s also possible to take the symmetric difference of two sets. This is the set of all elements in the union that aren’t in the intersection. Another way of putting it is that the symmetric difference contains all elements that are in exactly one set. Again, there’s an alternative notation (^), and an in-place version with the ungainly name symmetric_difference_update().

>>> S1 = sets.Set([1,2,3,4])
>>> S2 = sets.Set([3,4,5,6])
>>> S1.symmetric_difference(S2)
Set([1, 2, 5, 6])
>>> S1 ^ S2
Set([1, 2, 5, 6])
>>>

There are also issubset() and issuperset() methods for checking whether one set is a subset or superset of another:

>>> S1 = sets.Set([1,2,3])
>>> S2 = sets.Set([2,3])
>>> S2.issubset(S1)
True
>>> S1.issubset(S2)
False
>>> S1.issuperset(S2)
True
>>>

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PEP 218 [https://peps.python.org/pep-0218/] - Adding a Built-In Set Object Type

PEP written by Greg V. Wilson. Implemented by Greg V. Wilson, Alex Martelli, and GvR.

PEP 255: Simple Generators

In Python 2.2, generators were added as an optional feature, to be enabled by a from __future__ import generators directive. In 2.3 generators no longer need to be specially enabled, and are now always present; this means that yield is now always a keyword. The rest of this section is a copy of the description of generators from the “What’s New in Python 2.2” document; if you read it back when Python 2.2 came out, you can skip the rest of this section.

You’re doubtless familiar with how function calls work in Python or C. When you call a function, it gets a private namespace where its local variables are created. When the function reaches a return statement, the local variables are destroyed and the resulting value is returned to the caller. A later call to the same function will get a fresh new set of local variables. But, what if the local variables weren’t thrown away on exiting a function? What if you could later resume the function where it left off? This is what generators provide; they can be thought of as resumable functions.

Here’s the simplest example of a generator function:

def generate_ints(N):
    for i in range(N):
        yield i

A new keyword, yield, was introduced for generators. Any function containing a yield statement is a generator function; this is detected by Python’s bytecode compiler which compiles the function specially as a result.

When you call a generator function, it doesn’t return a single value; instead it returns a generator object that supports the iterator protocol. On executing the yield statement, the generator outputs the value of i, similar to a return statement. The big difference between yield and a return statement is that on reaching a yield the generator’s state of execution is suspended and local variables are preserved. On the next call to the generator’s .next() method, the function will resume executing immediately after the yield statement. (For complicated reasons, the yield statement isn’t allowed inside the try block of a try…finally statement; read PEP 255 [https://peps.python.org/pep-0255/] for a full explanation of the interaction between yield and exceptions.)

Here’s a sample usage of the generate_ints() generator:

>>> gen = generate_ints(3)
>>> gen
<generator object at 0x8117f90>
>>> gen.next()
0
>>> gen.next()
1
>>> gen.next()
2
>>> gen.next()
Traceback (most recent call last):
  File "stdin", line 1, in ?
  File "stdin", line 2, in generate_ints
StopIteration

You could equally write for i in generate_ints(5), or a,b,c = generate_ints(3).

Inside a generator function, the return statement can only be used without a value, and signals the end of the procession of values; afterwards the generator cannot return any further values. return with a value, such as return 5, is a syntax error inside a generator function. The end of the generator’s results can also be indicated by raising StopIteration manually, or by just letting the flow of execution fall off the bottom of the function.

You could achieve the effect of generators manually by writing your own class and storing all the local variables of the generator as instance variables. For example, returning a list of integers could be done by setting self.count to 0, and having the next() method increment self.count and return it. However, for a moderately complicated generator, writing a corresponding class would be much messier. Lib/test/test_generators.py contains a number of more interesting examples. The simplest one implements an in-order traversal of a tree using generators recursively.

# A recursive generator that generates Tree leaves in in-order.
def inorder(t):
    if t:
        for x in inorder(t.left):
            yield x
        yield t.label
        for x in inorder(t.right):
            yield x

Two other examples in Lib/test/test_generators.py produce solutions for the N-Queens problem (placing $N$ queens on an $NxN$ chess board so that no queen threatens another) and the Knight’s Tour (a route that takes a knight to every square of an $NxN$ chessboard without visiting any square twice).

The idea of generators comes from other programming languages, especially Icon (https://www2.cs.arizona.edu/icon/), where the idea of generators is central. In Icon, every expression and function call behaves like a generator. One example from “An Overview of the Icon Programming Language” at https://www2.cs.arizona.edu/icon/docs/ipd266.htm gives an idea of what this looks like:

sentence := "Store it in the neighboring harbor"
if (i := find("or", sentence)) > 5 then write(i)

In Icon the find() function returns the indexes at which the substring “or” is found: 3, 23, 33. In the if statement, i is first assigned a value of 3, but 3 is less than 5, so the comparison fails, and Icon retries it with the second value of 23. 23 is greater than 5, so the comparison now succeeds, and the code prints the value 23 to the screen.

Python doesn’t go nearly as far as Icon in adopting generators as a central concept. Generators are considered part of the core Python language, but learning or using them isn’t compulsory; if they don’t solve any problems that you have, feel free to ignore them. One novel feature of Python’s interface as compared to Icon’s is that a generator’s state is represented as a concrete object (the iterator) that can be passed around to other functions or stored in a data structure.

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PEP 255 [https://peps.python.org/pep-0255/] - Simple Generators

Written by Neil Schemenauer, Tim Peters, Magnus Lie Hetland. Implemented mostly by Neil Schemenauer and Tim Peters, with other fixes from the Python Labs crew.

PEP 263: Source Code Encodings

Python source files can now be declared as being in different character set encodings. Encodings are declared by including a specially formatted comment in the first or second line of the source file. For example, a UTF-8 file can be declared with:

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

Without such an encoding declaration, the default encoding used is 7-bit ASCII. Executing or importing modules that contain string literals with 8-bit characters and have no encoding declaration will result in a DeprecationWarning being signalled by Python 2.3; in 2.4 this will be a syntax error.

The encoding declaration only affects Unicode string literals, which will be converted to Unicode using the specified encoding. Note that Python identifiers are still restricted to ASCII characters, so you can’t have variable names that use characters outside of the usual alphanumerics.

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PEP 263 [https://peps.python.org/pep-0263/] - Defining Python Source Code Encodings

Written by Marc-André Lemburg and Martin von Löwis; implemented by Suzuki Hisao and Martin von Löwis.

PEP 273: Importing Modules from ZIP Archives

The new zipimport module adds support for importing modules from a ZIP-format archive. You don’t need to import the module explicitly; it will be automatically imported if a ZIP archive’s filename is added to sys.path. For example:

amk@nyman:~/src/python$ unzip -l /tmp/example.zip
Archive:  /tmp/example.zip
  Length     Date   Time    Name
 --------    ----   ----    ----
     8467  11-26-02 22:30   jwzthreading.py
 --------                   -------
     8467                   1 file
amk@nyman:~/src/python$ ./python
Python 2.3 (#1, Aug 1 2003, 19:54:32)
>>> import sys
>>> sys.path.insert(0, '/tmp/example.zip')  # Add .zip file to front of path
>>> import jwzthreading
>>> jwzthreading.__file__
'/tmp/example.zip/jwzthreading.py'
>>>

An entry in sys.path can now be the filename of a ZIP archive. The ZIP archive can contain any kind of files, but only files named *.py, *.pyc, or *.pyo can be imported. If an archive only contains *.py files, Python will not attempt to modify the archive by adding the corresponding *.pyc file, meaning that if a ZIP archive doesn’t contain *.pyc files, importing may be rather slow.

A path within the archive can also be specified to only import from a subdirectory; for example, the path /tmp/example.zip/lib/ would only import from the lib/ subdirectory within the archive.

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PEP 273 [https://peps.python.org/pep-0273/] - Import Modules from Zip Archives

Written by James C. Ahlstrom, who also provided an implementation. Python 2.3 follows the specification in PEP 273 [https://peps.python.org/pep-0273/], but uses an implementation written by Just van Rossum that uses the import hooks described in PEP 302 [https://peps.python.org/pep-0302/]. See section PEP 302: New Import Hooks for a description of the new import hooks.

PEP 277: Unicode file name support for Windows NT

On Windows NT, 2000, and XP, the system stores file names as Unicode strings. Traditionally, Python has represented file names as byte strings, which is inadequate because it renders some file names inaccessible.

Python now allows using arbitrary Unicode strings (within the limitations of the file system) for all functions that expect file names, most notably the open() built-in function. If a Unicode string is passed to os.listdir(), Python now returns a list of Unicode strings. A new function, os.getcwdu(), returns the current directory as a Unicode string.

Byte strings still work as file names, and on Windows Python will transparently convert them to Unicode using the mbcs encoding.

Other systems also allow Unicode strings as file names but convert them to byte strings before passing them to the system, which can cause a UnicodeError to be raised. Applications can test whether arbitrary Unicode strings are supported as file names by checking os.path.supports_unicode_filenames, a Boolean value.

Under MacOS, os.listdir() may now return Unicode filenames.

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PEP 277 [https://peps.python.org/pep-0277/] - Unicode file name support for Windows NT

Written by Neil Hodgson; implemented by Neil Hodgson, Martin von Löwis, and Mark Hammond.

PEP 278: Universal Newline Support

The three major operating systems used today are Microsoft Windows, Apple’s Macintosh OS, and the various Unix derivatives. A minor irritation of cross-platform work is that these three platforms all use different characters to mark the ends of lines in text files. Unix uses the linefeed (ASCII character 10), MacOS uses the carriage return (ASCII character 13), and Windows uses a two-character sequence of a carriage return plus a newline.

Python’s file objects can now support end of line conventions other than the one followed by the platform on which Python is running. Opening a file with the mode 'U' or 'rU' will open a file for reading in universal newlines mode. All three line ending conventions will be translated to a '\n' in the strings returned by the various file methods such as read() and readline().

Universal newline support is also used when importing modules and when executing a file with the execfile() function. This means that Python modules can be shared between all three operating systems without needing to convert the line-endings.

This feature can be disabled when compiling Python by specifying the --without-universal-newlines switch when running Python’s configure script.

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PEP 278 [https://peps.python.org/pep-0278/] - Universal Newline Support

Written and implemented by Jack Jansen.

PEP 279: enumerate()

A new built-in function, enumerate(), will make certain loops a bit clearer. enumerate(thing), where thing is either an iterator or a sequence, returns an iterator that will return (0, thing[0]), (1, thing[1]), (2, thing[2]), and so forth.

A common idiom to change every element of a list looks like this:

for i in range(len(L)):
    item = L[i]
    # ... compute some result based on item ...
    L[i] = result

This can be rewritten using enumerate() as:

for i, item in enumerate(L):
    # ... compute some result based on item ...
    L[i] = result

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PEP 279 [https://peps.python.org/pep-0279/] - The enumerate() built-in function

Written and implemented by Raymond D. Hettinger.

PEP 282: The logging Package

A standard package for writing logs, logging, has been added to Python 2.3. It provides a powerful and flexible mechanism for generating logging output which can then be filtered and processed in various ways. A configuration file written in a standard format can be used to control the logging behavior of a program. Python includes handlers that will write log records to standard error or to a file or socket, send them to the system log, or even e-mail them to a particular address; of course, it’s also possible to write your own handler classes.

The Logger class is the primary class. Most application code will deal with one or more Logger objects, each one used by a particular subsystem of the application. Each Logger is identified by a name, and names are organized into a hierarchy using . as the component separator. For example, you might have Logger instances named server, server.auth and server.network. The latter two instances are below server in the hierarchy. This means that if you turn up the verbosity for server or direct server messages to a different handler, the changes will also apply to records logged to server.auth and server.network. There’s also a root Logger that’s the parent of all other loggers.

For simple uses, the logging package contains some convenience functions that always use the root log:

import logging

logging.debug('Debugging information')
logging.info('Informational message')
logging.warning('Warning:config file %s not found', 'server.conf')
logging.error('Error occurred')
logging.critical('Critical error -- shutting down')

This produces the following output:

WARNING:root:Warning:config file server.conf not found
ERROR:root:Error occurred
CRITICAL:root:Critical error -- shutting down

In the default configuration, informational and debugging messages are suppressed and the output is sent to standard error. You can enable the display of informational and debugging messages by calling the setLevel() method on the root logger.

Notice the warning() call’s use of string formatting operators; all of the functions for logging messages take the arguments (msg, arg1, arg2, ...) and log the string resulting from msg % (arg1, arg2, ...).

There’s also an exception() function that records the most recent traceback. Any of the other functions will also record the traceback if you specify a true value for the keyword argument exc_info.

def f():
    try:    1/0
    except: logging.exception('Problem recorded')

f()

This produces the following output:

ERROR:root:Problem recorded
Traceback (most recent call last):
  File "t.py", line 6, in f
    1/0
ZeroDivisionError: integer division or modulo by zero

Slightly more advanced programs will use a logger other than the root logger. The getLogger(name) function is used to get a particular log, creating it if it doesn’t exist yet. getLogger(None) returns the root logger.

log = logging.getLogger('server')
 ...
log.info('Listening on port %i', port)
 ...
log.critical('Disk full')
 ...

Log records are usually propagated up the hierarchy, so a message logged to server.auth is also seen by server and root, but a Logger can prevent this by setting its propagate attribute to False.

There are more classes provided by the logging package that can be customized. When a Logger instance is told to log a message, it creates a LogRecord instance that is sent to any number of different Handler instances. Loggers and handlers can also have an attached list of filters, and each filter can cause the LogRecord to be ignored or can modify the record before passing it along. When they’re finally output, LogRecord instances are converted to text by a Formatter class. All of these classes can be replaced by your own specially written classes.

With all of these features the logging package should provide enough flexibility for even the most complicated applications. This is only an incomplete overview of its features, so please see the package’s reference documentation for all of the details. Reading PEP 282 [https://peps.python.org/pep-0282/] will also be helpful.

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PEP 282 [https://peps.python.org/pep-0282/] - A Logging System

Written by Vinay Sajip and Trent Mick; implemented by Vinay Sajip.

PEP 285: A Boolean Type

A Boolean type was added to Python 2.3. Two new constants were added to the __builtin__ module, True and False. (True and False constants were added to the built-ins in Python 2.2.1, but the 2.2.1 versions are simply set to integer values of 1 and 0 and aren’t a different type.)

The type object for this new type is named bool; the constructor for it takes any Python value and converts it to True or False.

>>> bool(1)
True
>>> bool(0)
False
>>> bool([])
False
>>> bool( (1,) )
True

Most of the standard library modules and built-in functions have been changed to return Booleans.

>>> obj = []
>>> hasattr(obj, 'append')
True
>>> isinstance(obj, list)
True
>>> isinstance(obj, tuple)
False

Python’s Booleans were added with the primary goal of making code clearer. For example, if you’re reading a function and encounter the statement return 1, you might wonder whether the 1 represents a Boolean truth value, an index, or a coefficient that multiplies some other quantity. If the statement is return True, however, the meaning of the return value is quite clear.

Python’s Booleans were not added for the sake of strict type-checking. A very strict language such as Pascal would also prevent you performing arithmetic with Booleans, and would require that the expression in an if statement always evaluate to a Boolean result. Python is not this strict and never will be, as PEP 285 [https://peps.python.org/pep-0285/] explicitly says. This means you can still use any expression in an if statement, even ones that evaluate to a list or tuple or some random object. The Boolean type is a subclass of the int class so that arithmetic using a Boolean still works.

>>> True + 1
2
>>> False + 1
1
>>> False * 75
0
>>> True * 75
75

To sum up True and False in a sentence: they’re alternative ways to spell the integer values 1 and 0, with the single difference that str() and repr() return the strings 'True' and 'False' instead of '1' and '0'.

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PEP 285 [https://peps.python.org/pep-0285/] - Adding a bool type

Written and implemented by GvR.

PEP 293: Codec Error Handling Callbacks

When encoding a Unicode string into a byte string, unencodable characters may be encountered. So far, Python has allowed specifying the error processing as either “strict” (raising UnicodeError), “ignore” (skipping the character), or “replace” (using a question mark in the output string), with “strict” being the default behavior. It may be desirable to specify alternative processing of such errors, such as inserting an XML character reference or HTML entity reference into the converted string.

Python now has a flexible framework to add different processing strategies. New error handlers can be added with codecs.register_error(), and codecs then can access the error handler with codecs.lookup_error(). An equivalent C API has been added for codecs written in C. The error handler gets the necessary state information such as the string being converted, the position in the string where the error was detected, and the target encoding. The handler can then either raise an exception or return a replacement string.

Two additional error handlers have been implemented using this framework: “backslashreplace” uses Python backslash quoting to represent unencodable characters and “xmlcharrefreplace” emits XML character references.

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PEP 293 [https://peps.python.org/pep-0293/] - Codec Error Handling Callbacks

Written and implemented by Walter Dörwald.

PEP 301: Package Index and Metadata for Distutils

Support for the long-requested Python catalog makes its first appearance in 2.3.

The heart of the catalog is the new Distutils register command. Running python setup.py register will collect the metadata describing a package, such as its name, version, maintainer, description, &c., and send it to a central catalog server. The resulting catalog is available from https://pypi.org.

To make the catalog a bit more useful, a new optional classifiers keyword argument has been added to the Distutils setup() function. A list of Trove [http://catb.org/~esr/trove/]-style strings can be supplied to help classify the software.

Here’s an example setup.py with classifiers, written to be compatible with older versions of the Distutils:

from distutils import core
kw = {'name': "Quixote",
      'version': "0.5.1",
      'description': "A highly Pythonic Web application framework",
      # ...
      }

if (hasattr(core, 'setup_keywords') and
    'classifiers' in core.setup_keywords):
    kw['classifiers'] = \
        ['Topic :: Internet :: WWW/HTTP :: Dynamic Content',
         'Environment :: No Input/Output (Daemon)',
         'Intended Audience :: Developers'],

core.setup(**kw)

The full list of classifiers can be obtained by running python setup.py register --list-classifiers.

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PEP 301 [https://peps.python.org/pep-0301/] - Package Index and Metadata for Distutils

Written and implemented by Richard Jones.

PEP 302: New Import Hooks

While it’s been possible to write custom import hooks ever since the ihooks module was introduced in Python 1.3, no one has ever been really happy with it because writing new import hooks is difficult and messy. There have been various proposed alternatives such as the imputil and iu modules, but none of them has ever gained much acceptance, and none of them were easily usable from C code.

PEP 302 [https://peps.python.org/pep-0302/] borrows ideas from its predecessors, especially from Gordon McMillan’s iu module. Three new items are added to the sys module:

sys.path_hooks is a list of callable objects; most often they’ll be classes. Each callable takes a string containing a path and either returns an importer object that will handle imports from this path or raises an ImportError exception if it can’t handle this path.

sys.path_importer_cache caches importer objects for each path, so sys.path_hooks will only need to be traversed once for each path.

sys.meta_path is a list of importer objects that will be traversed before sys.path is checked. This list is initially empty, but user code can add objects to it. Additional built-in and frozen modules can be imported by an object added to this list.

Importer objects must have a single method, find_module(fullname, path=None). fullname will be a module or package name, e.g. string or distutils.core. find_module() must return a loader object that has a single method, load_module(fullname), that creates and returns the corresponding module object.

Pseudo-code for Python’s new import logic, therefore, looks something like this (simplified a bit; see PEP 302 [https://peps.python.org/pep-0302/] for the full details):

for mp in sys.meta_path:
    loader = mp(fullname)
    if loader is not None:
        <module> = loader.load_module(fullname)

for path in sys.path:
    for hook in sys.path_hooks:
        try:
            importer = hook(path)
        except ImportError:
            # ImportError, so try the other path hooks
            pass
        else:
            loader = importer.find_module(fullname)
            <module> = loader.load_module(fullname)

# Not found!
raise ImportError

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PEP 302 [https://peps.python.org/pep-0302/] - New Import Hooks

Written by Just van Rossum and Paul Moore. Implemented by Just van Rossum.

PEP 305: Comma-separated Files

Comma-separated files are a format frequently used for exporting data from databases and spreadsheets. Python 2.3 adds a parser for comma-separated files.

Comma-separated format is deceptively simple at first glance:

Costs,150,200,3.95

Read a line and call line.split(','): what could be simpler? But toss in string data that can contain commas, and things get more complicated:

"Costs",150,200,3.95,"Includes taxes, shipping, and sundry items"

A big ugly regular expression can parse this, but using the new csv package is much simpler:

import csv

input = open('datafile', 'rb')
reader = csv.reader(input)
for line in reader:
    print line

The reader() function takes a number of different options. The field separator isn’t limited to the comma and can be changed to any character, and so can the quoting and line-ending characters.

Different dialects of comma-separated files can be defined and registered; currently there are two dialects, both used by Microsoft Excel. A separate csv.writer class will generate comma-separated files from a succession of tuples or lists, quoting strings that contain the delimiter.

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PEP 305 [https://peps.python.org/pep-0305/] - CSV File API

Written and implemented by Kevin Altis, Dave Cole, Andrew McNamara, Skip Montanaro, Cliff Wells.

PEP 307: Pickle Enhancements

The pickle and cPickle modules received some attention during the 2.3 development cycle. In 2.2, new-style classes could be pickled without difficulty, but they weren’t pickled very compactly; PEP 307 [https://peps.python.org/pep-0307/] quotes a trivial example where a new-style class results in a pickled string three times longer than that for a classic class.

The solution was to invent a new pickle protocol. The pickle.dumps() function has supported a text-or-binary flag for a long time. In 2.3, this flag is redefined from a Boolean to an integer: 0 is the old text-mode pickle format, 1 is the old binary format, and now 2 is a new 2.3-specific format. A new constant, pickle.HIGHEST_PROTOCOL, can be used to select the fanciest protocol available.

Unpickling is no longer considered a safe operation. 2.2’s pickle provided hooks for trying to prevent unsafe classes from being unpickled (specifically, a __safe_for_unpickling__ attribute), but none of this code was ever audited and therefore it’s all been ripped out in 2.3. You should not unpickle untrusted data in any version of Python.

To reduce the pickling overhead for new-style classes, a new interface for customizing pickling was added using three special methods: __getstate__(), __setstate__(), and __getnewargs__(). Consult PEP 307 [https://peps.python.org/pep-0307/] for the full semantics of these methods.

As a way to compress pickles yet further, it’s now possible to use integer codes instead of long strings to identify pickled classes. The Python Software Foundation will maintain a list of standardized codes; there’s also a range of codes for private use. Currently no codes have been specified.

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PEP 307 [https://peps.python.org/pep-0307/] - Extensions to the pickle protocol

Written and implemented by Guido van Rossum and Tim Peters.

Extended Slices

Ever since Python 1.4, the slicing syntax has supported an optional third “step” or “stride” argument. For example, these are all legal Python syntax: L[1:10:2], L[:-1:1], L[::-1]. This was added to Python at the request of the developers of Numerical Python, which uses the third argument extensively. However, Python’s built-in list, tuple, and string sequence types have never supported this feature, raising a TypeError if you tried it. Michael Hudson contributed a patch to fix this shortcoming.

For example, you can now easily extract the elements of a list that have even indexes:

>>> L = range(10)
>>> L[::2]
[0, 2, 4, 6, 8]

Negative values also work to make a copy of the same list in reverse order:

>>> L[::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

This also works for tuples, arrays, and strings:

>>> s='abcd'
>>> s[::2]
'ac'
>>> s[::-1]
'dcba'

If you have a mutable sequence such as a list or an array you can assign to or delete an extended slice, but there are some differences between assignment to extended and regular slices. Assignment to a regular slice can be used to change the length of the sequence:

>>> a = range(3)
>>> a
[0, 1, 2]
>>> a[1:3] = [4, 5, 6]
>>> a
[0, 4, 5, 6]

Extended slices aren’t this flexible. When assigning to an extended slice, the list on the right hand side of the statement must contain the same number of items as the slice it is replacing:

>>> a = range(4)
>>> a
[0, 1, 2, 3]
>>> a[::2]
[0, 2]
>>> a[::2] = [0, -1]
>>> a
[0, 1, -1, 3]
>>> a[::2] = [0,1,2]
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ValueError: attempt to assign sequence of size 3 to extended slice of size 2

Deletion is more straightforward:

>>> a = range(4)
>>> a
[0, 1, 2, 3]
>>> a[::2]
[0, 2]
>>> del a[::2]
>>> a
[1, 3]

One can also now pass slice objects to the __getitem__() methods of the built-in sequences:

>>> range(10).__getitem__(slice(0, 5, 2))
[0, 2, 4]

Or use slice objects directly in subscripts:

>>> range(10)[slice(0, 5, 2)]
[0, 2, 4]

To simplify implementing sequences that support extended slicing, slice objects now have a method indices(length) which, given the length of a sequence, returns a (start, stop, step) tuple that can be passed directly to range(). indices() handles omitted and out-of-bounds indices in a manner consistent with regular slices (and this innocuous phrase hides a welter of confusing details!). The method is intended to be used like this:

class FakeSeq:
    ...
    def calc_item(self, i):
        ...
    def __getitem__(self, item):
        if isinstance(item, slice):
            indices = item.indices(len(self))
            return FakeSeq([self.calc_item(i) for i in range(*indices)])
        else:
            return self.calc_item(i)

From this example you can also see that the built-in slice object is now the type object for the slice type, and is no longer a function. This is consistent with Python 2.2, where int, str, etc., underwent the same change.

Other Language Changes

Here are all of the changes that Python 2.3 makes to the core Python language.

The yield statement is now always a keyword, as described in section PEP 255: Simple Generators of this document.

A new built-in function enumerate() was added, as described in section PEP 279: enumerate() of this document.

Two new constants, True and False were added along with the built-in bool type, as described in section PEP 285: A Boolean Type of this document.

The int() type constructor will now return a long integer instead of raising an OverflowError when a string or floating-point number is too large to fit into an integer. This can lead to the paradoxical result that isinstance(int(expression), int) is false, but that seems unlikely to cause problems in practice.

Built-in types now support the extended slicing syntax, as described in section Extended Slices of this document.

A new built-in function, sum(iterable, start=0), adds up the numeric items in the iterable object and returns their sum. sum() only accepts numbers, meaning that you can’t use it to concatenate a bunch of strings. (Contributed by Alex Martelli.)

list.insert(pos, value) used to insert value at the front of the list when pos was negative. The behaviour has now been changed to be consistent with slice indexing, so when pos is -1 the value will be inserted before the last element, and so forth.

list.index(value), which searches for value within the list and returns its index, now takes optional start and stop arguments to limit the search to only part of the list.

Dictionaries have a new method, pop(key[, *default*]), that returns the value corresponding to key and removes that key/value pair from the dictionary. If the requested key isn’t present in the dictionary, default is returned if it’s specified and KeyError raised if it isn’t.

>>> d = {1:2}
>>> d
{1: 2}
>>> d.pop(4)
Traceback (most recent call last):
  File "stdin", line 1, in ?
KeyError: 4
>>> d.pop(1)
2
>>> d.pop(1)
Traceback (most recent call last):
  File "stdin", line 1, in ?
KeyError: 'pop(): dictionary is empty'
>>> d
{}
>>>

There’s also a new class method, dict.fromkeys(iterable, value), that creates a dictionary with keys taken from the supplied iterator iterable and all values set to value, defaulting to None.

(Patches contributed by Raymond Hettinger.)

Also, the dict() constructor now accepts keyword arguments to simplify creating small dictionaries:

>>> dict(red=1, blue=2, green=3, black=4)
{'blue': 2, 'black': 4, 'green': 3, 'red': 1}

(Contributed by Just van Rossum.)

The assert statement no longer checks the __debug__ flag, so you can no longer disable assertions by assigning to __debug__. Running Python with the -O switch will still generate code that doesn’t execute any assertions.

Most type objects are now callable, so you can use them to create new objects such as functions, classes, and modules. (This means that the new module can be deprecated in a future Python version, because you can now use the type objects available in the types module.) For example, you can create a new module object with the following code:

>>> import types
>>> m = types.ModuleType('abc','docstring')
>>> m
<module 'abc' (built-in)>
>>> m.__doc__
'docstring'

A new warning, PendingDeprecationWarning was added to indicate features which are in the process of being deprecated. The warning will not be printed by default. To check for use of features that will be deprecated in the future, supply -Walways::PendingDeprecationWarning:: on the command line or use warnings.filterwarnings().

The process of deprecating string-based exceptions, as in raise "Error occurred", has begun. Raising a string will now trigger PendingDeprecationWarning.

Using None as a variable name will now result in a SyntaxWarning warning. In a future version of Python, None may finally become a keyword.

The xreadlines() method of file objects, introduced in Python 2.1, is no longer necessary because files now behave as their own iterator. xreadlines() was originally introduced as a faster way to loop over all the lines in a file, but now you can simply write for line in file_obj. File objects also have a new read-only encoding attribute that gives the encoding used by the file; Unicode strings written to the file will be automatically converted to bytes using the given encoding.

The method resolution order used by new-style classes has changed, though you’ll only notice the difference if you have a really complicated inheritance hierarchy. Classic classes are unaffected by this change. Python 2.2 originally used a topological sort of a class’s ancestors, but 2.3 now uses the C3 algorithm as described in the paper “A Monotonic Superclass Linearization for Dylan” [https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.19.3910]. To understand the motivation for this change, read Michele Simionato’s article The Python 2.3 Method Resolution Order, or read the thread on python-dev starting with the message at https://mail.python.org/pipermail/python-dev/2002-October/029035.html. Samuele Pedroni first pointed out the problem and also implemented the fix by coding the C3 algorithm.

Python runs multithreaded programs by switching between threads after executing N bytecodes. The default value for N has been increased from 10 to 100 bytecodes, speeding up single-threaded applications by reducing the switching overhead. Some multithreaded applications may suffer slower response time, but that’s easily fixed by setting the limit back to a lower number using sys.setcheckinterval(N). The limit can be retrieved with the new sys.getcheckinterval() function.

One minor but far-reaching change is that the names of extension types defined by the modules included with Python now contain the module and a '.' in front of the type name. For example, in Python 2.2, if you created a socket and printed its __class__, you’d get this output:

>>> s = socket.socket()
>>> s.__class__
<type 'socket'>

In 2.3, you get this:

>>> s.__class__
<type '_socket.socket'>

One of the noted incompatibilities between old- and new-style classes has been removed: you can now assign to the __name__ and __bases__ attributes of new-style classes. There are some restrictions on what can be assigned to __bases__ along the lines of those relating to assigning to an instance’s __class__ attribute.

String Changes

The in operator now works differently for strings. Previously, when evaluating X in Y where X and Y are strings, X could only be a single character. That’s now changed; X can be a string of any length, and X in Y will return True if X is a substring of Y. If X is the empty string, the result is always True.

>>> 'ab' in 'abcd'
True
>>> 'ad' in 'abcd'
False
>>> '' in 'abcd'
True

Note that this doesn’t tell you where the substring starts; if you need that information, use the find() string method.

The strip(), lstrip(), and rstrip() string methods now have an optional argument for specifying the characters to strip. The default is still to remove all whitespace characters:

>>> '   abc '.strip()
'abc'
>>> '><><abc<><><>'.strip('<>')
'abc'
>>> '><><abc<><><>\n'.strip('<>')
'abc<><><>\n'
>>> u'\u4000\u4001abc\u4000'.strip(u'\u4000')
u'\u4001abc'
>>>

(Suggested by Simon Brunning and implemented by Walter Dörwald.)

The startswith() and endswith() string methods now accept negative numbers for the start and end parameters.

Another new string method is zfill(), originally a function in the string module. zfill() pads a numeric string with zeros on the left until it’s the specified width. Note that the % operator is still more flexible and powerful than zfill().

>>> '45'.zfill(4)
'0045'
>>> '12345'.zfill(4)
'12345'
>>> 'goofy'.zfill(6)
'0goofy'

(Contributed by Walter Dörwald.)

A new type object, basestring, has been added. Both 8-bit strings and Unicode strings inherit from this type, so isinstance(obj, basestring) will return True for either kind of string. It’s a completely abstract type, so you can’t create basestring instances.

Interned strings are no longer immortal and will now be garbage-collected in the usual way when the only reference to them is from the internal dictionary of interned strings. (Implemented by Oren Tirosh.)

Optimizations

The creation of new-style class instances has been made much faster; they’re now faster than classic classes!

The sort() method of list objects has been extensively rewritten by Tim Peters, and the implementation is significantly faster.

Multiplication of large long integers is now much faster thanks to an implementation of Karatsuba multiplication, an algorithm that scales better than the O(n²) required for the grade-school multiplication algorithm. (Original patch by Christopher A. Craig, and significantly reworked by Tim Peters.)

The SET_LINENO opcode is now gone. This may provide a small speed increase, depending on your compiler’s idiosyncrasies. See section Other Changes and Fixes for a longer explanation. (Removed by Michael Hudson.)

xrange() objects now have their own iterator, making for i in xrange(n) slightly faster than for i in range(n). (Patch by Raymond Hettinger.)

A number of small rearrangements have been made in various hotspots to improve performance, such as inlining a function or removing some code. (Implemented mostly by GvR, but lots of people have contributed single changes.)

The net result of the 2.3 optimizations is that Python 2.3 runs the pystone benchmark around 25% faster than Python 2.2.

New, Improved, and Deprecated Modules

As usual, Python’s standard library received a number of enhancements and bug fixes. Here’s a partial list of the most notable changes, sorted alphabetically by module name. Consult the Misc/NEWS file in the source tree for a more complete list of changes, or look through the CVS logs for all the details.

The array module now supports arrays of Unicode characters using the 'u' format character. Arrays also now support using the += assignment operator to add another array’s contents, and the *= assignment operator to repeat an array. (Contributed by Jason Orendorff.)

The bsddb module has been replaced by version 4.1.6 of the PyBSDDB [https://pybsddb.sourceforge.net] package, providing a more complete interface to the transactional features of the BerkeleyDB library.

The old version of the module has been renamed to bsddb185 and is no longer built automatically; you’ll have to edit Modules/Setup to enable it. Note that the new bsddb package is intended to be compatible with the old module, so be sure to file bugs if you discover any incompatibilities. When upgrading to Python 2.3, if the new interpreter is compiled with a new version of the underlying BerkeleyDB library, you will almost certainly have to convert your database files to the new version. You can do this fairly easily with the new scripts db2pickle.py and pickle2db.py which you will find in the distribution’s Tools/scripts directory. If you’ve already been using the PyBSDDB package and importing it as bsddb3, you will have to change your import statements to import it as bsddb.

The new bz2 module is an interface to the bz2 data compression library. bz2-compressed data is usually smaller than corresponding zlib-compressed data. (Contributed by Gustavo Niemeyer.)

A set of standard date/time types has been added in the new datetime module. See the following section for more details.

The Distutils Extension class now supports an extra constructor argument named depends for listing additional source files that an extension depends on. This lets Distutils recompile the module if any of the dependency files are modified. For example, if sampmodule.c includes the header file sample.h, you would create the Extension object like this:

ext = Extension("samp",
                sources=["sampmodule.c"],
                depends=["sample.h"])

Modifying sample.h would then cause the module to be recompiled. (Contributed by Jeremy Hylton.)

Other minor changes to Distutils: it now checks for the CC, CFLAGS, CPP, LDFLAGS, and CPPFLAGS environment variables, using them to override the settings in Python’s configuration (contributed by Robert Weber).

Previously the doctest module would only search the docstrings of public methods and functions for test cases, but it now also examines private ones as well. The DocTestSuite() function creates a unittest.TestSuite object from a set of doctest tests.

The new gc.get_referents(object) function returns a list of all the objects referenced by object.

The getopt module gained a new function, gnu_getopt(), that supports the same arguments as the existing getopt() function but uses GNU-style scanning mode. The existing getopt() stops processing options as soon as a non-option argument is encountered, but in GNU-style mode processing continues, meaning that options and arguments can be mixed. For example:

>>> getopt.getopt(['-f', 'filename', 'output', '-v'], 'f:v')
([('-f', 'filename')], ['output', '-v'])
>>> getopt.gnu_getopt(['-f', 'filename', 'output', '-v'], 'f:v')
([('-f', 'filename'), ('-v', '')], ['output'])

(Contributed by Peter Åstrand.)

The grp, pwd, and resource modules now return enhanced tuples:

>>> import grp
>>> g = grp.getgrnam('amk')
>>> g.gr_name, g.gr_gid
('amk', 500)

The gzip module can now handle files exceeding 2 GiB.

The new heapq module contains an implementation of a heap queue algorithm. A heap is an array-like data structure that keeps items in a partially sorted order such that, for every index k, heap[k] <= heap[2*k+1] and heap[k] <= heap[2*k+2]. This makes it quick to remove the smallest item, and inserting a new item while maintaining the heap property is O(log n). (See https://xlinux.nist.gov/dads//HTML/priorityque.html for more information about the priority queue data structure.)

The heapq module provides heappush() and heappop() functions for adding and removing items while maintaining the heap property on top of some other mutable Python sequence type. Here’s an example that uses a Python list:

>>> import heapq
>>> heap = []
>>> for item in [3, 7, 5, 11, 1]:
...    heapq.heappush(heap, item)
...
>>> heap
[1, 3, 5, 11, 7]
>>> heapq.heappop(heap)
1
>>> heapq.heappop(heap)
3
>>> heap
[5, 7, 11]

(Contributed by Kevin O’Connor.)

The IDLE integrated development environment has been updated using the code from the IDLEfork project (https://idlefork.sourceforge.net). The most notable feature is that the code being developed is now executed in a subprocess, meaning that there’s no longer any need for manual reload() operations. IDLE’s core code has been incorporated into the standard library as the idlelib package.

The imaplib module now supports IMAP over SSL. (Contributed by Piers Lauder and Tino Lange.)

The itertools contains a number of useful functions for use with iterators, inspired by various functions provided by the ML and Haskell languages. For example, itertools.ifilter(predicate, iterator) returns all elements in the iterator for which the function predicate() returns True, and itertools.repeat(obj, N) returns obj N times. There are a number of other functions in the module; see the package’s reference documentation for details. (Contributed by Raymond Hettinger.)

Two new functions in the math module, degrees(rads) and radians(degs), convert between radians and degrees. Other functions in the math module such as math.sin() and math.cos() have always required input values measured in radians. Also, an optional base argument was added to math.log() to make it easier to compute logarithms for bases other than e and 10. (Contributed by Raymond Hettinger.)

Several new POSIX functions (getpgid(), killpg(), lchown(), loadavg(), major(), makedev(), minor(), and mknod()) were added to the posix module that underlies the os module. (Contributed by Gustavo Niemeyer, Geert Jansen, and Denis S. Otkidach.)

In the os module, the *stat() family of functions can now report fractions of a second in a timestamp. Such time stamps are represented as floats, similar to the value returned by time.time().

During testing, it was found that some applications will break if time stamps are floats. For compatibility, when using the tuple interface of the stat_result time stamps will be represented as integers. When using named fields (a feature first introduced in Python 2.2), time stamps are still represented as integers, unless os.stat_float_times() is invoked to enable float return values:

>>> os.stat("/tmp").st_mtime
1034791200
>>> os.stat_float_times(True)
>>> os.stat("/tmp").st_mtime
1034791200.6335014

In Python 2.4, the default will change to always returning floats.

Application developers should enable this feature only if all their libraries work properly when confronted with floating-point time stamps, or if they use the tuple API. If used, the feature should be activated on an application level instead of trying to enable it on a per-use basis.

The optparse module contains a new parser for command-line arguments that can convert option values to a particular Python type and will automatically generate a usage message. See the following section for more details.

The old and never-documented linuxaudiodev module has been deprecated, and a new version named ossaudiodev has been added. The module was renamed because the OSS sound drivers can be used on platforms other than Linux, and the interface has also been tidied and brought up to date in various ways. (Contributed by Greg Ward and Nicholas FitzRoy-Dale.)

The new platform module contains a number of functions that try to determine various properties of the platform you’re running on. There are functions for getting the architecture, CPU type, the Windows OS version, and even the Linux distribution version. (Contributed by Marc-André Lemburg.)

The parser objects provided by the pyexpat module can now optionally buffer character data, resulting in fewer calls to your character data handler and therefore faster performance. Setting the parser object’s buffer_text attribute to True will enable buffering.

The sample(population, k) function was added to the random module. population is a sequence or xrange object containing the elements of a population, and sample() chooses k elements from the population without replacing chosen elements. k can be any value up to len(population). For example:

>>> days = ['Mo', 'Tu', 'We', 'Th', 'Fr', 'St', 'Sn']
>>> random.sample(days, 3)      # Choose 3 elements
['St', 'Sn', 'Th']
>>> random.sample(days, 7)      # Choose 7 elements
['Tu', 'Th', 'Mo', 'We', 'St', 'Fr', 'Sn']
>>> random.sample(days, 7)      # Choose 7 again
['We', 'Mo', 'Sn', 'Fr', 'Tu', 'St', 'Th']
>>> random.sample(days, 8)      # Can't choose eight
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "random.py", line 414, in sample
      raise ValueError, "sample larger than population"
ValueError: sample larger than population
>>> random.sample(xrange(1,10000,2), 10)   # Choose ten odd nos. under 10000
[3407, 3805, 1505, 7023, 2401, 2267, 9733, 3151, 8083, 9195]

The random module now uses a new algorithm, the Mersenne Twister, implemented in C. It’s faster and more extensively studied than the previous algorithm.

(All changes contributed by Raymond Hettinger.)

The readline module also gained a number of new functions: get_history_item(), get_current_history_length(), and redisplay().

The rexec and Bastion modules have been declared dead, and attempts to import them will fail with a RuntimeError. New-style classes provide new ways to break out of the restricted execution environment provided by rexec, and no one has interest in fixing them or time to do so. If you have applications using rexec, rewrite them to use something else.

(Sticking with Python 2.2 or 2.1 will not make your applications any safer because there are known bugs in the rexec module in those versions. To repeat: if you’re using rexec, stop using it immediately.)

The rotor module has been deprecated because the algorithm it uses for encryption is not believed to be secure. If you need encryption, use one of the several AES Python modules that are available separately.

The shutil module gained a move(src, dest) function that recursively moves a file or directory to a new location.

Support for more advanced POSIX signal handling was added to the signal but then removed again as it proved impossible to make it work reliably across platforms.

The socket module now supports timeouts. You can call the settimeout(t) method on a socket object to set a timeout of t seconds. Subsequent socket operations that take longer than t seconds to complete will abort and raise a socket.timeout exception.

The original timeout implementation was by Tim O’Malley. Michael Gilfix integrated it into the Python socket module and shepherded it through a lengthy review. After the code was checked in, Guido van Rossum rewrote parts of it. (This is a good example of a collaborative development process in action.)

On Windows, the socket module now ships with Secure Sockets Layer (SSL) support.

The value of the C PYTHON_API_VERSION macro is now exposed at the Python level as sys.api_version. The current exception can be cleared by calling the new sys.exc_clear() function.

The new tarfile module allows reading from and writing to tar-format archive files. (Contributed by Lars Gustäbel.)

The new textwrap module contains functions for wrapping strings containing paragraphs of text. The wrap(text, width) function takes a string and returns a list containing the text split into lines of no more than the chosen width. The fill(text, width) function returns a single string, reformatted to fit into lines no longer than the chosen width. (As you can guess, fill() is built on top of wrap(). For example:

>>> import textwrap
>>> paragraph = "Not a whit, we defy augury: ... more text ..."
>>> textwrap.wrap(paragraph, 60)
["Not a whit, we defy augury: there's a special providence in",
 "the fall of a sparrow. If it be now, 'tis not to come; if it",
 ...]
>>> print textwrap.fill(paragraph, 35)
Not a whit, we defy augury: there's
a special providence in the fall of
a sparrow. If it be now, 'tis not
to come; if it be not to come, it
will be now; if it be not now, yet
it will come: the readiness is all.
>>>

The module also contains a TextWrapper class that actually implements the text wrapping strategy. Both the TextWrapper class and the wrap() and fill() functions support a number of additional keyword arguments for fine-tuning the formatting; consult the module’s documentation for details. (Contributed by Greg Ward.)

The thread and threading modules now have companion modules, dummy_thread and dummy_threading, that provide a do-nothing implementation of the thread module’s interface for platforms where threads are not supported. The intention is to simplify thread-aware modules (ones that don’t rely on threads to run) by putting the following code at the top:

try:
    import threading as _threading
except ImportError:
    import dummy_threading as _threading

In this example, _threading is used as the module name to make it clear that the module being used is not necessarily the actual threading module. Code can call functions and use classes in _threading whether or not threads are supported, avoiding an if statement and making the code slightly clearer. This module will not magically make multithreaded code run without threads; code that waits for another thread to return or to do something will simply hang forever.

The time module’s strptime() function has long been an annoyance because it uses the platform C library’s strptime() implementation, and different platforms sometimes have odd bugs. Brett Cannon contributed a portable implementation that’s written in pure Python and should behave identically on all platforms.

The new timeit module helps measure how long snippets of Python code take to execute. The timeit.py file can be run directly from the command line, or the module’s Timer class can be imported and used directly. Here’s a short example that figures out whether it’s faster to convert an 8-bit string to Unicode by appending an empty Unicode string to it or by using the unicode() function:

import timeit

timer1 = timeit.Timer('unicode("abc")')
timer2 = timeit.Timer('"abc" + u""')

# Run three trials
print timer1.repeat(repeat=3, number=100000)
print timer2.repeat(repeat=3, number=100000)

# On my laptop this outputs:
# [0.36831796169281006, 0.37441694736480713, 0.35304892063140869]
# [0.17574405670166016, 0.18193507194519043, 0.17565798759460449]

The Tix module has received various bug fixes and updates for the current version of the Tix package.

The Tkinter module now works with a thread-enabled version of Tcl. Tcl’s threading model requires that widgets only be accessed from the thread in which they’re created; accesses from another thread can cause Tcl to panic. For certain Tcl interfaces, Tkinter will now automatically avoid this when a widget is accessed from a different thread by marshalling a command, passing it to the correct thread, and waiting for the results. Other interfaces can’t be handled automatically but Tkinter will now raise an exception on such an access so that you can at least find out about the problem. See https://mail.python.org/pipermail/python-dev/2002-December/031107.html for a more detailed explanation of this change. (Implemented by Martin von Löwis.)

Calling Tcl methods through _tkinter no longer returns only strings. Instead, if Tcl returns other objects those objects are converted to their Python equivalent, if one exists, or wrapped with a _tkinter.Tcl_Obj object if no Python equivalent exists. This behavior can be controlled through the wantobjects() method of tkapp objects.

When using _tkinter through the Tkinter module (as most Tkinter applications will), this feature is always activated. It should not cause compatibility problems, since Tkinter would always convert string results to Python types where possible.

If any incompatibilities are found, the old behavior can be restored by setting the wantobjects variable in the Tkinter module to false before creating the first tkapp object.

import Tkinter
Tkinter.wantobjects = 0

Any breakage caused by this change should be reported as a bug.

The UserDict module has a new DictMixin class which defines all dictionary methods for classes that already have a minimum mapping interface. This greatly simplifies writing classes that need to be substitutable for dictionaries, such as the classes in the shelve module.

Adding the mix-in as a superclass provides the full dictionary interface whenever the class defines __getitem__(), __setitem__(), __delitem__(), and keys(). For example:

>>> import UserDict
>>> class SeqDict(UserDict.DictMixin):
...     """Dictionary lookalike implemented with lists."""
...     def __init__(self):
...         self.keylist = []
...         self.valuelist = []
...     def __getitem__(self, key):
...         try:
...             i = self.keylist.index(key)
...         except ValueError:
...             raise KeyError
...         return self.valuelist[i]
...     def __setitem__(self, key, value):
...         try:
...             i = self.keylist.index(key)
...             self.valuelist[i] = value
...         except ValueError:
...             self.keylist.append(key)
...             self.valuelist.append(value)
...     def __delitem__(self, key):
...         try:
...             i = self.keylist.index(key)
...         except ValueError:
...             raise KeyError
...         self.keylist.pop(i)
...         self.valuelist.pop(i)
...     def keys(self):
...         return list(self.keylist)
...
>>> s = SeqDict()
>>> dir(s)      # See that other dictionary methods are implemented
['__cmp__', '__contains__', '__delitem__', '__doc__', '__getitem__',
 '__init__', '__iter__', '__len__', '__module__', '__repr__',
 '__setitem__', 'clear', 'get', 'has_key', 'items', 'iteritems',
 'iterkeys', 'itervalues', 'keylist', 'keys', 'pop', 'popitem',
 'setdefault', 'update', 'valuelist', 'values']

(Contributed by Raymond Hettinger.)

The DOM implementation in xml.dom.minidom can now generate XML output in a particular encoding by providing an optional encoding argument to the toxml() and toprettyxml() methods of DOM nodes.

The xmlrpclib module now supports an XML-RPC extension for handling nil data values such as Python’s None. Nil values are always supported on unmarshalling an XML-RPC response. To generate requests containing None, you must supply a true value for the allow_none parameter when creating a Marshaller instance.

The new DocXMLRPCServer module allows writing self-documenting XML-RPC servers. Run it in demo mode (as a program) to see it in action. Pointing the web browser to the RPC server produces pydoc-style documentation; pointing xmlrpclib to the server allows invoking the actual methods. (Contributed by Brian Quinlan.)

Support for internationalized domain names (RFCs 3454, 3490, 3491, and 3492) has been added. The “idna” encoding can be used to convert between a Unicode domain name and the ASCII-compatible encoding (ACE) of that name.

>{}>{}> u"www.Alliancefrançaise.nu".encode("idna")
'www.xn--alliancefranaise-npb.nu'

The socket module has also been extended to transparently convert Unicode hostnames to the ACE version before passing them to the C library. Modules that deal with hostnames such as httplib and ftplib) also support Unicode host names; httplib also sends HTTP Host headers using the ACE version of the domain name. urllib supports Unicode URLs with non-ASCII host names as long as the path part of the URL is ASCII only.

To implement this change, the stringprep module, the mkstringprep tool and the punycode encoding have been added.

Date/Time Type

Date and time types suitable for expressing timestamps were added as the datetime module. The types don’t support different calendars or many fancy features, and just stick to the basics of representing time.

The three primary types are: date, representing a day, month, and year; time, consisting of hour, minute, and second; and datetime, which contains all the attributes of both date and time. There’s also a timedelta class representing differences between two points in time, and time zone logic is implemented by classes inheriting from the abstract tzinfo class.

You can create instances of date and time by either supplying keyword arguments to the appropriate constructor, e.g. datetime.date(year=1972, month=10, day=15), or by using one of a number of class methods. For example, the today() class method returns the current local date.

Once created, instances of the date/time classes are all immutable. There are a number of methods for producing formatted strings from objects:

>>> import datetime
>>> now = datetime.datetime.now()
>>> now.isoformat()
'2002-12-30T21:27:03.994956'
>>> now.ctime()  # Only available on date, datetime
'Mon Dec 30 21:27:03 2002'
>>> now.strftime('%Y %d %b')
'2002 30 Dec'

The replace() method allows modifying one or more fields of a date or datetime instance, returning a new instance:

>>> d = datetime.datetime.now()
>>> d
datetime.datetime(2002, 12, 30, 22, 15, 38, 827738)
>>> d.replace(year=2001, hour = 12)
datetime.datetime(2001, 12, 30, 12, 15, 38, 827738)
>>>

Instances can be compared, hashed, and converted to strings (the result is the same as that of isoformat()). date and datetime instances can be subtracted from each other, and added to timedelta instances. The largest missing feature is that there’s no standard library support for parsing strings and getting back a date or datetime.

For more information, refer to the module’s reference documentation. (Contributed by Tim Peters.)

The optparse Module

The getopt module provides simple parsing of command-line arguments. The new optparse module (originally named Optik) provides more elaborate command-line parsing that follows the Unix conventions, automatically creates the output for --help, and can perform different actions for different options.

You start by creating an instance of OptionParser and telling it what your program’s options are.

import sys
from optparse import OptionParser

op = OptionParser()
op.add_option('-i', '--input',
              action='store', type='string', dest='input',
              help='set input filename')
op.add_option('-l', '--length',
              action='store', type='int', dest='length',
              help='set maximum length of output')

Parsing a command line is then done by calling the parse_args() method.

options, args = op.parse_args(sys.argv[1:])
print options
print args

This returns an object containing all of the option values, and a list of strings containing the remaining arguments.

Invoking the script with the various arguments now works as you’d expect it to. Note that the length argument is automatically converted to an integer.

$ ./python opt.py -i data arg1
<Values at 0x400cad4c: {'input': 'data', 'length': None}>
['arg1']
$ ./python opt.py --input=data --length=4
<Values at 0x400cad2c: {'input': 'data', 'length': 4}>
[]
$

The help message is automatically generated for you:

$ ./python opt.py --help
usage: opt.py [options]

options:
  -h, --help            show this help message and exit
  -iINPUT, --input=INPUT
                        set input filename
  -lLENGTH, --length=LENGTH
                        set maximum length of output
$

See the module’s documentation for more details.

Optik was written by Greg Ward, with suggestions from the readers of the Getopt SIG.

Pymalloc: A Specialized Object Allocator

Pymalloc, a specialized object allocator written by Vladimir Marangozov, was a feature added to Python 2.1. Pymalloc is intended to be faster than the system malloc() and to have less memory overhead for allocation patterns typical of Python programs. The allocator uses C’s malloc() function to get large pools of memory and then fulfills smaller memory requests from these pools.

In 2.1 and 2.2, pymalloc was an experimental feature and wasn’t enabled by default; you had to explicitly enable it when compiling Python by providing the --with-pymalloc option to the configure script. In 2.3, pymalloc has had further enhancements and is now enabled by default; you’ll have to supply --without-pymalloc to disable it.

This change is transparent to code written in Python; however, pymalloc may expose bugs in C extensions. Authors of C extension modules should test their code with pymalloc enabled, because some incorrect code may cause core dumps at runtime.

There’s one particularly common error that causes problems. There are a number of memory allocation functions in Python’s C API that have previously just been aliases for the C library’s malloc() and free(), meaning that if you accidentally called mismatched functions the error wouldn’t be noticeable. When the object allocator is enabled, these functions aren’t aliases of malloc() and free() any more, and calling the wrong function to free memory may get you a core dump. For example, if memory was allocated using PyObject_Malloc(), it has to be freed using PyObject_Free(), not free(). A few modules included with Python fell afoul of this and had to be fixed; doubtless there are more third-party modules that will have the same problem.

As part of this change, the confusing multiple interfaces for allocating memory have been consolidated down into two API families. Memory allocated with one family must not be manipulated with functions from the other family. There is one family for allocating chunks of memory and another family of functions specifically for allocating Python objects.

To allocate and free an undistinguished chunk of memory use the “raw memory” family: PyMem_Malloc(), PyMem_Realloc(), and PyMem_Free().

The “object memory” family is the interface to the pymalloc facility described above and is biased towards a large number of “small” allocations: PyObject_Malloc(), PyObject_Realloc(), and PyObject_Free().

To allocate and free Python objects, use the “object” family PyObject_New, PyObject_NewVar, and PyObject_Del().

Thanks to lots of work by Tim Peters, pymalloc in 2.3 also provides debugging features to catch memory overwrites and doubled frees in both extension modules and in the interpreter itself. To enable this support, compile a debugging version of the Python interpreter by running configure with --with-pydebug.

To aid extension writers, a header file Misc/pymemcompat.h is distributed with the source to Python 2.3 that allows Python extensions to use the 2.3 interfaces to memory allocation while compiling against any version of Python since 1.5.2. You would copy the file from Python’s source distribution and bundle it with the source of your extension.

더 보기

https://hg.python.org/cpython/file/default/Objects/obmalloc.c

For the full details of the pymalloc implementation, see the comments at the top of the file Objects/obmalloc.c in the Python source code. The above link points to the file within the python.org SVN browser.

Build and C API Changes

Changes to Python’s build process and to the C API include:

The cycle detection implementation used by the garbage collection has proven to be stable, so it’s now been made mandatory. You can no longer compile Python without it, and the --with-cycle-gc switch to configure has been removed.

Python can now optionally be built as a shared library (libpython2.3.so) by supplying --enable-shared when running Python’s configure script. (Contributed by Ondrej Palkovsky.)

The DL_EXPORT and DL_IMPORT macros are now deprecated. Initialization functions for Python extension modules should now be declared using the new macro PyMODINIT_FUNC, while the Python core will generally use the PyAPI_FUNC and PyAPI_DATA macros.

The interpreter can be compiled without any docstrings for the built-in functions and modules by supplying --without-doc-strings to the configure script. This makes the Python executable about 10% smaller, but will also mean that you can’t get help for Python’s built-ins. (Contributed by Gustavo Niemeyer.)

The PyArg_NoArgs() macro is now deprecated, and code that uses it should be changed. For Python 2.2 and later, the method definition table can specify the METH_NOARGS flag, signalling that there are no arguments, and the argument checking can then be removed. If compatibility with pre-2.2 versions of Python is important, the code could use PyArg_ParseTuple(args, "") instead, but this will be slower than using METH_NOARGS.

PyArg_ParseTuple() accepts new format characters for various sizes of unsigned integers: B for unsigned char, H for unsigned short int, I for unsigned int, and K for unsigned long long.

A new function, PyObject_DelItemString(mapping, char *key) was added as shorthand for PyObject_DelItem(mapping, PyString_New(key)).

File objects now manage their internal string buffer differently, increasing it exponentially when needed. This results in the benchmark tests in Lib/test/test_bufio.py speeding up considerably (from 57 seconds to 1.7 seconds, according to one measurement).

It’s now possible to define class and static methods for a C extension type by setting either the METH_CLASS or METH_STATIC flags in a method’s PyMethodDef structure.

Python now includes a copy of the Expat XML parser’s source code, removing any dependence on a system version or local installation of Expat.

If you dynamically allocate type objects in your extension, you should be aware of a change in the rules relating to the __module__ and __name__ attributes. In summary, you will want to ensure the type’s dictionary contains a '__module__' key; making the module name the part of the type name leading up to the final period will no longer have the desired effect. For more detail, read the API reference documentation or the source.

Port-Specific Changes

Support for a port to IBM’s OS/2 using the EMX runtime environment was merged into the main Python source tree. EMX is a POSIX emulation layer over the OS/2 system APIs. The Python port for EMX tries to support all the POSIX-like capability exposed by the EMX runtime, and mostly succeeds; fork() and fcntl() are restricted by the limitations of the underlying emulation layer. The standard OS/2 port, which uses IBM’s Visual Age compiler, also gained support for case-sensitive import semantics as part of the integration of the EMX port into CVS. (Contributed by Andrew MacIntyre.)

On MacOS, most toolbox modules have been weaklinked to improve backward compatibility. This means that modules will no longer fail to load if a single routine is missing on the current OS version. Instead calling the missing routine will raise an exception. (Contributed by Jack Jansen.)

The RPM spec files, found in the Misc/RPM/ directory in the Python source distribution, were updated for 2.3. (Contributed by Sean Reifschneider.)

Other new platforms now supported by Python include AtheOS (http://www.atheos.cx/), GNU/Hurd, and OpenVMS.

Other Changes and Fixes

As usual, there were a bunch of other improvements and bugfixes scattered throughout the source tree. A search through the CVS change logs finds there were 523 patches applied and 514 bugs fixed between Python 2.2 and 2.3. Both figures are likely to be underestimates.

Some of the more notable changes are:

If the PYTHONINSPECT environment variable is set, the Python interpreter will enter the interactive prompt after running a Python program, as if Python had been invoked with the -i option. The environment variable can be set before running the Python interpreter, or it can be set by the Python program as part of its execution.

The regrtest.py script now provides a way to allow “all resources except foo.” A resource name passed to the -u option can now be prefixed with a hyphen ('-') to mean “remove this resource.” For example, the option ‘-uall,-bsddb’ could be used to enable the use of all resources except bsddb.

The tools used to build the documentation now work under Cygwin as well as Unix.

The SET_LINENO opcode has been removed. Back in the mists of time, this opcode was needed to produce line numbers in tracebacks and support trace functions (for, e.g., pdb). Since Python 1.5, the line numbers in tracebacks have been computed using a different mechanism that works with “python -O”. For Python 2.3 Michael Hudson implemented a similar scheme to determine when to call the trace function, removing the need for SET_LINENO entirely.

It would be difficult to detect any resulting difference from Python code, apart from a slight speed up when Python is run without -O.

C extensions that access the f_lineno field of frame objects should instead call PyCode_Addr2Line(f->f_code, f->f_lasti). This will have the added effect of making the code work as desired under “python -O” in earlier versions of Python.

A nifty new feature is that trace functions can now assign to the f_lineno attribute of frame objects, changing the line that will be executed next. A jump command has been added to the pdb debugger taking advantage of this new feature. (Implemented by Richie Hindle.)

Porting to Python 2.3

This section lists previously described changes that may require changes to your code:

yield is now always a keyword; if it’s used as a variable name in your code, a different name must be chosen.

For strings X and Y, X in Y now works if X is more than one character long.

The int() type constructor will now return a long integer instead of raising an OverflowError when a string or floating-point number is too large to fit into an integer.

If you have Unicode strings that contain 8-bit characters, you must declare the file’s encoding (UTF-8, Latin-1, or whatever) by adding a comment to the top of the file. See section PEP 263: Source Code Encodings for more information.

Calling Tcl methods through _tkinter no longer returns only strings. Instead, if Tcl returns other objects those objects are converted to their Python equivalent, if one exists, or wrapped with a _tkinter.Tcl_Obj object if no Python equivalent exists.

Large octal and hex literals such as 0xffffffff now trigger a FutureWarning. Currently they’re stored as 32-bit numbers and result in a negative value, but in Python 2.4 they’ll become positive long integers.

There are a few ways to fix this warning. If you really need a positive number, just add an L to the end of the literal. If you’re trying to get a 32-bit integer with low bits set and have previously used an expression such as ~(1 << 31), it’s probably clearest to start with all bits set and clear the desired upper bits. For example, to clear just the top bit (bit 31), you could write 0xffffffffL &~(1L<<31).

You can no longer disable assertions by assigning to __debug__.

The Distutils setup() function has gained various new keyword arguments such as depends. Old versions of the Distutils will abort if passed unknown keywords. A solution is to check for the presence of the new get_distutil_options() function in your setup.py and only uses the new keywords with a version of the Distutils that supports them:

from distutils import core

kw = {'sources': 'foo.c', ...}
if hasattr(core, 'get_distutil_options'):
    kw['depends'] = ['foo.h']
ext = Extension(**kw)

Using None as a variable name will now result in a SyntaxWarning warning.

Names of extension types defined by the modules included with Python now contain the module and a '.' in front of the type name.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Jeff Bauer, Simon Brunning, Brett Cannon, Michael Chermside, Andrew Dalke, Scott David Daniels, Fred L. Drake, Jr., David Fraser, Kelly Gerber, Raymond Hettinger, Michael Hudson, Chris Lambert, Detlef Lannert, Martin von Löwis, Andrew MacIntyre, Lalo Martins, Chad Netzer, Gustavo Niemeyer, Neal Norwitz, Hans Nowak, Chris Reedy, Francesco Ricciardi, Vinay Sajip, Neil Schemenauer, Roman Suzi, Jason Tishler, Just van Rossum.

What’s New in Python 2.2

Author:

A.M. Kuchling

Introduction

This article explains the new features in Python 2.2.2, released on October 14, 2002. Python 2.2.2 is a bugfix release of Python 2.2, originally released on December 21, 2001.

Python 2.2 can be thought of as the “cleanup release”. There are some features such as generators and iterators that are completely new, but most of the changes, significant and far-reaching though they may be, are aimed at cleaning up irregularities and dark corners of the language design.

This article doesn’t attempt to provide a complete specification of the new features, but instead provides a convenient overview. For full details, you should refer to the documentation for Python 2.2, such as the Python Library Reference [https://docs.python.org/2.2/lib/lib.html] and the Python Reference Manual [https://docs.python.org/2.2/ref/ref.html]. If you want to understand the complete implementation and design rationale for a change, refer to the PEP for a particular new feature.

PEPs 252 and 253: Type and Class Changes

The largest and most far-reaching changes in Python 2.2 are to Python’s model of objects and classes. The changes should be backward compatible, so it’s likely that your code will continue to run unchanged, but the changes provide some amazing new capabilities. Before beginning this, the longest and most complicated section of this article, I’ll provide an overview of the changes and offer some comments.

A long time ago I wrote a web page listing flaws in Python’s design. One of the most significant flaws was that it’s impossible to subclass Python types implemented in C. In particular, it’s not possible to subclass built-in types, so you can’t just subclass, say, lists in order to add a single useful method to them. The UserList module provides a class that supports all of the methods of lists and that can be subclassed further, but there’s lots of C code that expects a regular Python list and won’t accept a UserList instance.

Python 2.2 fixes this, and in the process adds some exciting new capabilities. A brief summary:

You can subclass built-in types such as lists and even integers, and your subclasses should work in every place that requires the original type.

It’s now possible to define static and class methods, in addition to the instance methods available in previous versions of Python.

It’s also possible to automatically call methods on accessing or setting an instance attribute by using a new mechanism called properties. Many uses of __getattr__() can be rewritten to use properties instead, making the resulting code simpler and faster. As a small side benefit, attributes can now have docstrings, too.

The list of legal attributes for an instance can be limited to a particular set using slots, making it possible to safeguard against typos and perhaps make more optimizations possible in future versions of Python.

Some users have voiced concern about all these changes. Sure, they say, the new features are neat and lend themselves to all sorts of tricks that weren’t possible in previous versions of Python, but they also make the language more complicated. Some people have said that they’ve always recommended Python for its simplicity, and feel that its simplicity is being lost.

Personally, I think there’s no need to worry. Many of the new features are quite esoteric, and you can write a lot of Python code without ever needed to be aware of them. Writing a simple class is no more difficult than it ever was, so you don’t need to bother learning or teaching them unless they’re actually needed. Some very complicated tasks that were previously only possible from C will now be possible in pure Python, and to my mind that’s all for the better.

I’m not going to attempt to cover every single corner case and small change that were required to make the new features work. Instead this section will paint only the broad strokes. See section Related Links, “Related Links”, for further sources of information about Python 2.2’s new object model.

Old and New Classes

First, you should know that Python 2.2 really has two kinds of classes: classic or old-style classes, and new-style classes. The old-style class model is exactly the same as the class model in earlier versions of Python. All the new features described in this section apply only to new-style classes. This divergence isn’t intended to last forever; eventually old-style classes will be dropped, possibly in Python 3.0.

So how do you define a new-style class? You do it by subclassing an existing new-style class. Most of Python’s built-in types, such as integers, lists, dictionaries, and even files, are new-style classes now. A new-style class named object, the base class for all built-in types, has also been added so if no built-in type is suitable, you can just subclass object:

class C(object):
    def __init__ (self):
        ...
    ...

This means that class statements that don’t have any base classes are always classic classes in Python 2.2. (Actually you can also change this by setting a module-level variable named __metaclass__ — see PEP 253 [https://peps.python.org/pep-0253/] for the details — but it’s easier to just subclass object.)

The type objects for the built-in types are available as built-ins, named using a clever trick. Python has always had built-in functions named int(), float(), and str(). In 2.2, they aren’t functions any more, but type objects that behave as factories when called.

>>> int
<type 'int'>
>>> int('123')
123

To make the set of types complete, new type objects such as dict() and file() have been added. Here’s a more interesting example, adding a lock() method to file objects:

class LockableFile(file):
    def lock (self, operation, length=0, start=0, whence=0):
        import fcntl
        return fcntl.lockf(self.fileno(), operation,
                           length, start, whence)

The now-obsolete posixfile module contained a class that emulated all of a file object’s methods and also added a lock() method, but this class couldn’t be passed to internal functions that expected a built-in file, something which is possible with our new LockableFile.

Descriptors

In previous versions of Python, there was no consistent way to discover what attributes and methods were supported by an object. There were some informal conventions, such as defining __members__ and __methods__ attributes that were lists of names, but often the author of an extension type or a class wouldn’t bother to define them. You could fall back on inspecting the __dict__ of an object, but when class inheritance or an arbitrary __getattr__() hook were in use this could still be inaccurate.

The one big idea underlying the new class model is that an API for describing the attributes of an object using descriptors has been formalized. Descriptors specify the value of an attribute, stating whether it’s a method or a field. With the descriptor API, static methods and class methods become possible, as well as more exotic constructs.

Attribute descriptors are objects that live inside class objects, and have a few attributes of their own:

__name__ is the attribute’s name.

__doc__ is the attribute’s docstring.

__get__(object) is a method that retrieves the attribute value from object.

__set__(object, value) sets the attribute on object to value.

__delete__(object, value) deletes the value attribute of object.

For example, when you write obj.x, the steps that Python actually performs are:

descriptor = obj.__class__.x
descriptor.__get__(obj)

For methods, descriptor.__get__ returns a temporary object that’s callable, and wraps up the instance and the method to be called on it. This is also why static methods and class methods are now possible; they have descriptors that wrap up just the method, or the method and the class. As a brief explanation of these new kinds of methods, static methods aren’t passed the instance, and therefore resemble regular functions. Class methods are passed the class of the object, but not the object itself. Static and class methods are defined like this:

class C(object):
    def f(arg1, arg2):
        ...
    f = staticmethod(f)

    def g(cls, arg1, arg2):
        ...
    g = classmethod(g)

The staticmethod() function takes the function f(), and returns it wrapped up in a descriptor so it can be stored in the class object. You might expect there to be special syntax for creating such methods (def static f, defstatic f(), or something like that) but no such syntax has been defined yet; that’s been left for future versions of Python.

More new features, such as slots and properties, are also implemented as new kinds of descriptors, and it’s not difficult to write a descriptor class that does something novel. For example, it would be possible to write a descriptor class that made it possible to write Eiffel-style preconditions and postconditions for a method. A class that used this feature might be defined like this:

from eiffel import eiffelmethod

class C(object):
    def f(self, arg1, arg2):
        # The actual function
        ...
    def pre_f(self):
        # Check preconditions
        ...
    def post_f(self):
        # Check postconditions
        ...

    f = eiffelmethod(f, pre_f, post_f)

Note that a person using the new eiffelmethod() doesn’t have to understand anything about descriptors. This is why I think the new features don’t increase the basic complexity of the language. There will be a few wizards who need to know about it in order to write eiffelmethod() or the ZODB or whatever, but most users will just write code on top of the resulting libraries and ignore the implementation details.

Multiple Inheritance: The Diamond Rule

Multiple inheritance has also been made more useful through changing the rules under which names are resolved. Consider this set of classes (diagram taken from PEP 253 [https://peps.python.org/pep-0253/] by Guido van Rossum):

      class A:
        ^ ^  def save(self): ...
       /   \
      /     \
     /       \
    /         \
class B     class C:
    ^         ^  def save(self): ...
     \       /
      \     /
       \   /
        \ /
      class D

The lookup rule for classic classes is simple but not very smart; the base classes are searched depth-first, going from left to right. A reference to D.save() will search the classes D, B, and then A, where save() would be found and returned. C.save() would never be found at all. This is bad, because if C’s save() method is saving some internal state specific to C, not calling it will result in that state never getting saved.

New-style classes follow a different algorithm that’s a bit more complicated to explain, but does the right thing in this situation. (Note that Python 2.3 changes this algorithm to one that produces the same results in most cases, but produces more useful results for really complicated inheritance graphs.)

List all the base classes, following the classic lookup rule and include a class multiple times if it’s visited repeatedly. In the above example, the list of visited classes is [D, B, A, C, A].

Scan the list for duplicated classes. If any are found, remove all but one occurrence, leaving the last one in the list. In the above example, the list becomes [D, B, C, A] after dropping duplicates.

Following this rule, referring to D.save() will return C.save(), which is the behaviour we’re after. This lookup rule is the same as the one followed by Common Lisp. A new built-in function, super(), provides a way to get at a class’s superclasses without having to reimplement Python’s algorithm. The most commonly used form will be super(class, obj), which returns a bound superclass object (not the actual class object). This form will be used in methods to call a method in the superclass; for example, D’s save() method would look like this:

class D (B,C):
    def save (self):
        # Call superclass .save()
        super(D, self).save()
        # Save D's private information here
        ...

super() can also return unbound superclass objects when called as super(class) or super(class1, class2), but this probably won’t often be useful.

Attribute Access

A fair number of sophisticated Python classes define hooks for attribute access using __getattr__(); most commonly this is done for convenience, to make code more readable by automatically mapping an attribute access such as obj.parent into a method call such as obj.get_parent. Python 2.2 adds some new ways of controlling attribute access.

First, __getattr__(attr_name) is still supported by new-style classes, and nothing about it has changed. As before, it will be called when an attempt is made to access obj.foo and no attribute named foo is found in the instance’s dictionary.

New-style classes also support a new method, __getattribute__(attr_name). The difference between the two methods is that __getattribute__() is always called whenever any attribute is accessed, while the old __getattr__() is only called if foo isn’t found in the instance’s dictionary.

However, Python 2.2’s support for properties will often be a simpler way to trap attribute references. Writing a __getattr__() method is complicated because to avoid recursion you can’t use regular attribute accesses inside them, and instead have to mess around with the contents of __dict__. __getattr__() methods also end up being called by Python when it checks for other methods such as __repr__() or __coerce__(), and so have to be written with this in mind. Finally, calling a function on every attribute access results in a sizable performance loss.

property is a new built-in type that packages up three functions that get, set, or delete an attribute, and a docstring. For example, if you want to define a size attribute that’s computed, but also settable, you could write:

class C(object):
    def get_size (self):
        result = ... computation ...
        return result
    def set_size (self, size):
        ... compute something based on the size
        and set internal state appropriately ...

    # Define a property.  The 'delete this attribute'
    # method is defined as None, so the attribute
    # can't be deleted.
    size = property(get_size, set_size,
                    None,
                    "Storage size of this instance")

That is certainly clearer and easier to write than a pair of __getattr__()/__setattr__() methods that check for the size attribute and handle it specially while retrieving all other attributes from the instance’s __dict__. Accesses to size are also the only ones which have to perform the work of calling a function, so references to other attributes run at their usual speed.

Finally, it’s possible to constrain the list of attributes that can be referenced on an object using the new __slots__ class attribute. Python objects are usually very dynamic; at any time it’s possible to define a new attribute on an instance by just doing obj.new_attr=1. A new-style class can define a class attribute named __slots__ to limit the legal attributes to a particular set of names. An example will make this clear:

>>> class C(object):
...     __slots__ = ('template', 'name')
...
>>> obj = C()
>>> print obj.template
None
>>> obj.template = 'Test'
>>> print obj.template
Test
>>> obj.newattr = None
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
AttributeError: 'C' object has no attribute 'newattr'

Note how you get an AttributeError on the attempt to assign to an attribute not listed in __slots__.

Related Links

This section has just been a quick overview of the new features, giving enough of an explanation to start you programming, but many details have been simplified or ignored. Where should you go to get a more complete picture?

The Descriptor Guide is a lengthy tutorial introduction to the descriptor features, written by Guido van Rossum. If my description has whetted your appetite, go read this tutorial next, because it goes into much more detail about the new features while still remaining quite easy to read.

Next, there are two relevant PEPs, PEP 252 [https://peps.python.org/pep-0252/] and PEP 253 [https://peps.python.org/pep-0253/]. PEP 252 [https://peps.python.org/pep-0252/] is titled “Making Types Look More Like Classes”, and covers the descriptor API. PEP 253 [https://peps.python.org/pep-0253/] is titled “Subtyping Built-in Types”, and describes the changes to type objects that make it possible to subtype built-in objects. PEP 253 [https://peps.python.org/pep-0253/] is the more complicated PEP of the two, and at a few points the necessary explanations of types and meta-types may cause your head to explode. Both PEPs were written and implemented by Guido van Rossum, with substantial assistance from the rest of the Zope Corp. team.

Finally, there’s the ultimate authority: the source code. Most of the machinery for the type handling is in Objects/typeobject.c, but you should only resort to it after all other avenues have been exhausted, including posting a question to python-list or python-dev.

PEP 234: Iterators

Another significant addition to 2.2 is an iteration interface at both the C and Python levels. Objects can define how they can be looped over by callers.

In Python versions up to 2.1, the usual way to make for item in obj work is to define a __getitem__() method that looks something like this:

def __getitem__(self, index):
    return <next item>

__getitem__() is more properly used to define an indexing operation on an object so that you can write obj[5] to retrieve the sixth element. It’s a bit misleading when you’re using this only to support for loops. Consider some file-like object that wants to be looped over; the index parameter is essentially meaningless, as the class probably assumes that a series of __getitem__() calls will be made with index incrementing by one each time. In other words, the presence of the __getitem__() method doesn’t mean that using file[5] to randomly access the sixth element will work, though it really should.

In Python 2.2, iteration can be implemented separately, and __getitem__() methods can be limited to classes that really do support random access. The basic idea of iterators is simple. A new built-in function, iter(obj) or iter(C, sentinel), is used to get an iterator. iter(obj) returns an iterator for the object obj, while iter(C, sentinel) returns an iterator that will invoke the callable object C until it returns sentinel to signal that the iterator is done.

Python classes can define an __iter__() method, which should create and return a new iterator for the object; if the object is its own iterator, this method can just return self. In particular, iterators will usually be their own iterators. Extension types implemented in C can implement a tp_iter function in order to return an iterator, and extension types that want to behave as iterators can define a tp_iternext function.

So, after all this, what do iterators actually do? They have one required method, next(), which takes no arguments and returns the next value. When there are no more values to be returned, calling next() should raise the StopIteration exception.

>>> L = [1,2,3]
>>> i = iter(L)
>>> print i
<iterator object at 0x8116870>
>>> i.next()
1
>>> i.next()
2
>>> i.next()
3
>>> i.next()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
StopIteration
>>>

In 2.2, Python’s for statement no longer expects a sequence; it expects something for which iter() will return an iterator. For backward compatibility and convenience, an iterator is automatically constructed for sequences that don’t implement __iter__() or a tp_iter slot, so for i in [1,2,3] will still work. Wherever the Python interpreter loops over a sequence, it’s been changed to use the iterator protocol. This means you can do things like this:

>>> L = [1,2,3]
>>> i = iter(L)
>>> a,b,c = i
>>> a,b,c
(1, 2, 3)

Iterator support has been added to some of Python’s basic types. Calling iter() on a dictionary will return an iterator which loops over its keys:

>>> m = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
...      'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
>>> for key in m: print key, m[key]
...
Mar 3
Feb 2
Aug 8
Sep 9
May 5
Jun 6
Jul 7
Jan 1
Apr 4
Nov 11
Dec 12
Oct 10

That’s just the default behaviour. If you want to iterate over keys, values, or key/value pairs, you can explicitly call the iterkeys(), itervalues(), or iteritems() methods to get an appropriate iterator. In a minor related change, the in operator now works on dictionaries, so key in dict is now equivalent to dict.has_key(key).

Files also provide an iterator, which calls the readline() method until there are no more lines in the file. This means you can now read each line of a file using code like this:

for line in file:
    # do something for each line
    ...

Note that you can only go forward in an iterator; there’s no way to get the previous element, reset the iterator, or make a copy of it. An iterator object could provide such additional capabilities, but the iterator protocol only requires a next() method.

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PEP 234 [https://peps.python.org/pep-0234/] - Iterators

Written by Ka-Ping Yee and GvR; implemented by the Python Labs crew, mostly by GvR and Tim Peters.

PEP 255: Simple Generators

Generators are another new feature, one that interacts with the introduction of iterators.

You’re doubtless familiar with how function calls work in Python or C. When you call a function, it gets a private namespace where its local variables are created. When the function reaches a return statement, the local variables are destroyed and the resulting value is returned to the caller. A later call to the same function will get a fresh new set of local variables. But, what if the local variables weren’t thrown away on exiting a function? What if you could later resume the function where it left off? This is what generators provide; they can be thought of as resumable functions.

Here’s the simplest example of a generator function:

def generate_ints(N):
    for i in range(N):
        yield i

A new keyword, yield, was introduced for generators. Any function containing a yield statement is a generator function; this is detected by Python’s bytecode compiler which compiles the function specially as a result. Because a new keyword was introduced, generators must be explicitly enabled in a module by including a from __future__ import generators statement near the top of the module’s source code. In Python 2.3 this statement will become unnecessary.

When you call a generator function, it doesn’t return a single value; instead it returns a generator object that supports the iterator protocol. On executing the yield statement, the generator outputs the value of i, similar to a return statement. The big difference between yield and a return statement is that on reaching a yield the generator’s state of execution is suspended and local variables are preserved. On the next call to the generator’s next() method, the function will resume executing immediately after the yield statement. (For complicated reasons, the yield statement isn’t allowed inside the try block of a try…finally statement; read PEP 255 [https://peps.python.org/pep-0255/] for a full explanation of the interaction between yield and exceptions.)

Here’s a sample usage of the generate_ints() generator:

>>> gen = generate_ints(3)
>>> gen
<generator object at 0x8117f90>
>>> gen.next()
0
>>> gen.next()
1
>>> gen.next()
2
>>> gen.next()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "<stdin>", line 2, in generate_ints
StopIteration

You could equally write for i in generate_ints(5), or a,b,c = generate_ints(3).

Inside a generator function, the return statement can only be used without a value, and signals the end of the procession of values; afterwards the generator cannot return any further values. return with a value, such as return 5, is a syntax error inside a generator function. The end of the generator’s results can also be indicated by raising StopIteration manually, or by just letting the flow of execution fall off the bottom of the function.

You could achieve the effect of generators manually by writing your own class and storing all the local variables of the generator as instance variables. For example, returning a list of integers could be done by setting self.count to 0, and having the next() method increment self.count and return it. However, for a moderately complicated generator, writing a corresponding class would be much messier. Lib/test/test_generators.py contains a number of more interesting examples. The simplest one implements an in-order traversal of a tree using generators recursively.

# A recursive generator that generates Tree leaves in in-order.
def inorder(t):
    if t:
        for x in inorder(t.left):
            yield x
        yield t.label
        for x in inorder(t.right):
            yield x

Two other examples in Lib/test/test_generators.py produce solutions for the N-Queens problem (placing $N$ queens on an $NxN$ chess board so that no queen threatens another) and the Knight’s Tour (a route that takes a knight to every square of an $NxN$ chessboard without visiting any square twice).

The idea of generators comes from other programming languages, especially Icon (https://www2.cs.arizona.edu/icon/), where the idea of generators is central. In Icon, every expression and function call behaves like a generator. One example from “An Overview of the Icon Programming Language” at https://www2.cs.arizona.edu/icon/docs/ipd266.htm gives an idea of what this looks like:

sentence := "Store it in the neighboring harbor"
if (i := find("or", sentence)) > 5 then write(i)

In Icon the find() function returns the indexes at which the substring “or” is found: 3, 23, 33. In the if statement, i is first assigned a value of 3, but 3 is less than 5, so the comparison fails, and Icon retries it with the second value of 23. 23 is greater than 5, so the comparison now succeeds, and the code prints the value 23 to the screen.

Python doesn’t go nearly as far as Icon in adopting generators as a central concept. Generators are considered a new part of the core Python language, but learning or using them isn’t compulsory; if they don’t solve any problems that you have, feel free to ignore them. One novel feature of Python’s interface as compared to Icon’s is that a generator’s state is represented as a concrete object (the iterator) that can be passed around to other functions or stored in a data structure.

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PEP 255 [https://peps.python.org/pep-0255/] - Simple Generators

Written by Neil Schemenauer, Tim Peters, Magnus Lie Hetland. Implemented mostly by Neil Schemenauer and Tim Peters, with other fixes from the Python Labs crew.

PEP 237: Unifying Long Integers and Integers

In recent versions, the distinction between regular integers, which are 32-bit values on most machines, and long integers, which can be of arbitrary size, was becoming an annoyance. For example, on platforms that support files larger than 2**32 bytes, the tell() method of file objects has to return a long integer. However, there were various bits of Python that expected plain integers and would raise an error if a long integer was provided instead. For example, in Python 1.5, only regular integers could be used as a slice index, and 'abc'[1L:] would raise a TypeError exception with the message ‘slice index must be int’.

Python 2.2 will shift values from short to long integers as required. The ‘L’ suffix is no longer needed to indicate a long integer literal, as now the compiler will choose the appropriate type. (Using the ‘L’ suffix will be discouraged in future 2.x versions of Python, triggering a warning in Python 2.4, and probably dropped in Python 3.0.) Many operations that used to raise an OverflowError will now return a long integer as their result. For example:

>>> 1234567890123
1234567890123L
>>> 2 ** 64
18446744073709551616L

In most cases, integers and long integers will now be treated identically. You can still distinguish them with the type() built-in function, but that’s rarely needed.

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PEP 237 [https://peps.python.org/pep-0237/] - Unifying Long Integers and Integers

Written by Moshe Zadka and Guido van Rossum. Implemented mostly by Guido van Rossum.

PEP 238: Changing the Division Operator

The most controversial change in Python 2.2 heralds the start of an effort to fix an old design flaw that’s been in Python from the beginning. Currently Python’s division operator, /, behaves like C’s division operator when presented with two integer arguments: it returns an integer result that’s truncated down when there would be a fractional part. For example, 3/2 is 1, not 1.5, and (-1)/2 is -1, not -0.5. This means that the results of division can vary unexpectedly depending on the type of the two operands and because Python is dynamically typed, it can be difficult to determine the possible types of the operands.

(The controversy is over whether this is really a design flaw, and whether it’s worth breaking existing code to fix this. It’s caused endless discussions on python-dev, and in July 2001 erupted into a storm of acidly sarcastic postings on comp.lang.python. I won’t argue for either side here and will stick to describing what’s implemented in 2.2. Read PEP 238 [https://peps.python.org/pep-0238/] for a summary of arguments and counter-arguments.)

Because this change might break code, it’s being introduced very gradually. Python 2.2 begins the transition, but the switch won’t be complete until Python 3.0.

First, I’ll borrow some terminology from PEP 238 [https://peps.python.org/pep-0238/]. “True division” is the division that most non-programmers are familiar with: 3/2 is 1.5, 1/4 is 0.25, and so forth. “Floor division” is what Python’s / operator currently does when given integer operands; the result is the floor of the value returned by true division. “Classic division” is the current mixed behaviour of /; it returns the result of floor division when the operands are integers, and returns the result of true division when one of the operands is a floating-point number.

Here are the changes 2.2 introduces:

A new operator, //, is the floor division operator. (Yes, we know it looks like C++’s comment symbol.) // always performs floor division no matter what the types of its operands are, so 1 // 2 is 0 and 1.0 // 2.0 is also 0.0.

// is always available in Python 2.2; you don’t need to enable it using a __future__ statement.

By including a from __future__ import division in a module, the / operator will be changed to return the result of true division, so 1/2 is 0.5. Without the __future__ statement, / still means classic division. The default meaning of / will not change until Python 3.0.

Classes can define methods called __truediv__() and __floordiv__() to overload the two division operators. At the C level, there are also slots in the PyNumberMethods structure so extension types can define the two operators.

Python 2.2 supports some command-line arguments for testing whether code will work with the changed division semantics. Running python with -Q warn will cause a warning to be issued whenever division is applied to two integers. You can use this to find code that’s affected by the change and fix it. By default, Python 2.2 will simply perform classic division without a warning; the warning will be turned on by default in Python 2.3.

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PEP 238 [https://peps.python.org/pep-0238/] - Changing the Division Operator

Written by Moshe Zadka and Guido van Rossum. Implemented by Guido van Rossum..

Unicode Changes

Python’s Unicode support has been enhanced a bit in 2.2. Unicode strings are usually stored as UCS-2, as 16-bit unsigned integers. Python 2.2 can also be compiled to use UCS-4, 32-bit unsigned integers, as its internal encoding by supplying --enable-unicode=ucs4 to the configure script. (It’s also possible to specify --disable-unicode to completely disable Unicode support.)

When built to use UCS-4 (a “wide Python”), the interpreter can natively handle Unicode characters from U+000000 to U+110000, so the range of legal values for the unichr() function is expanded accordingly. Using an interpreter compiled to use UCS-2 (a “narrow Python”), values greater than 65535 will still cause unichr() to raise a ValueError exception. This is all described in PEP 261 [https://peps.python.org/pep-0261/], “Support for ‘wide’ Unicode characters”; consult it for further details.

Another change is simpler to explain. Since their introduction, Unicode strings have supported an encode() method to convert the string to a selected encoding such as UTF-8 or Latin-1. A symmetric decode([*encoding*]) method has been added to 8-bit strings (though not to Unicode strings) in 2.2. decode() assumes that the string is in the specified encoding and decodes it, returning whatever is returned by the codec.

Using this new feature, codecs have been added for tasks not directly related to Unicode. For example, codecs have been added for uu-encoding, MIME’s base64 encoding, and compression with the zlib module:

>>> s = """Here is a lengthy piece of redundant, overly verbose,
... and repetitive text.
... """
>>> data = s.encode('zlib')
>>> data
'x\x9c\r\xc9\xc1\r\x80 \x10\x04\xc0?Ul...'
>>> data.decode('zlib')
'Here is a lengthy piece of redundant, overly verbose,\nand repetitive text.\n'
>>> print s.encode('uu')
begin 666 <data>
M2&5R92!I<R!A(&QE;F=T:'D@<&EE8V4@;V8@<F5D=6YD86YT+"!O=F5R;'D@
>=F5R8F]S92P*86YD(')E<&5T:71I=F4@=&5X="X*

end
>>> "sheesh".encode('rot-13')
'furrfu'

To convert a class instance to Unicode, a __unicode__() method can be defined by a class, analogous to __str__().

encode(), decode(), and __unicode__() were implemented by Marc-André Lemburg. The changes to support using UCS-4 internally were implemented by Fredrik Lundh and Martin von Löwis.

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PEP 261 [https://peps.python.org/pep-0261/] - Support for ‘wide’ Unicode characters

Written by Paul Prescod.

PEP 227: Nested Scopes

In Python 2.1, statically nested scopes were added as an optional feature, to be enabled by a from __future__ import nested_scopes directive. In 2.2 nested scopes no longer need to be specially enabled, and are now always present. The rest of this section is a copy of the description of nested scopes from my “What’s New in Python 2.1” document; if you read it when 2.1 came out, you can skip the rest of this section.

The largest change introduced in Python 2.1, and made complete in 2.2, is to Python’s scoping rules. In Python 2.0, at any given time there are at most three namespaces used to look up variable names: local, module-level, and the built-in namespace. This often surprised people because it didn’t match their intuitive expectations. For example, a nested recursive function definition doesn’t work:

def f():
    ...
    def g(value):
        ...
        return g(value-1) + 1
    ...

The function g() will always raise a NameError exception, because the binding of the name g isn’t in either its local namespace or in the module-level namespace. This isn’t much of a problem in practice (how often do you recursively define interior functions like this?), but this also made using the lambda expression clumsier, and this was a problem in practice. In code which uses lambda you can often find local variables being copied by passing them as the default values of arguments.

def find(self, name):
    "Return list of any entries equal to 'name'"
    L = filter(lambda x, name=name: x == name,
               self.list_attribute)
    return L

The readability of Python code written in a strongly functional style suffers greatly as a result.

The most significant change to Python 2.2 is that static scoping has been added to the language to fix this problem. As a first effect, the name=name default argument is now unnecessary in the above example. Put simply, when a given variable name is not assigned a value within a function (by an assignment, or the def, class, or import statements), references to the variable will be looked up in the local namespace of the enclosing scope. A more detailed explanation of the rules, and a dissection of the implementation, can be found in the PEP.

This change may cause some compatibility problems for code where the same variable name is used both at the module level and as a local variable within a function that contains further function definitions. This seems rather unlikely though, since such code would have been pretty confusing to read in the first place.

One side effect of the change is that the from module import * and exec statements have been made illegal inside a function scope under certain conditions. The Python reference manual has said all along that from module import * is only legal at the top level of a module, but the CPython interpreter has never enforced this before. As part of the implementation of nested scopes, the compiler which turns Python source into bytecodes has to generate different code to access variables in a containing scope. from module import * and exec make it impossible for the compiler to figure this out, because they add names to the local namespace that are unknowable at compile time. Therefore, if a function contains function definitions or lambda expressions with free variables, the compiler will flag this by raising a SyntaxError exception.

To make the preceding explanation a bit clearer, here’s an example:

x = 1
def f():
    # The next line is a syntax error
    exec 'x=2'
    def g():
        return x

Line 4 containing the exec statement is a syntax error, since exec would define a new local variable named x whose value should be accessed by g().

This shouldn’t be much of a limitation, since exec is rarely used in most Python code (and when it is used, it’s often a sign of a poor design anyway).

더 보기

PEP 227 [https://peps.python.org/pep-0227/] - Statically Nested Scopes

Written and implemented by Jeremy Hylton.

New and Improved Modules

The xmlrpclib module was contributed to the standard library by Fredrik Lundh, providing support for writing XML-RPC clients. XML-RPC is a simple remote procedure call protocol built on top of HTTP and XML. For example, the following snippet retrieves a list of RSS channels from the O’Reilly Network, and then lists the recent headlines for one channel:

import xmlrpclib
s = xmlrpclib.Server(
      'http://www.oreillynet.com/meerkat/xml-rpc/server.php')
channels = s.meerkat.getChannels()
# channels is a list of dictionaries, like this:
# [{'id': 4, 'title': 'Freshmeat Daily News'}
#  {'id': 190, 'title': '32Bits Online'},
#  {'id': 4549, 'title': '3DGamers'}, ... ]

# Get the items for one channel
items = s.meerkat.getItems( {'channel': 4} )

# 'items' is another list of dictionaries, like this:
# [{'link': 'http://freshmeat.net/releases/52719/',
#   'description': 'A utility which converts HTML to XSL FO.',
#   'title': 'html2fo 0.3 (Default)'}, ... ]

The SimpleXMLRPCServer module makes it easy to create straightforward XML-RPC servers. See http://xmlrpc.scripting.com/ for more information about XML-RPC.

The new hmac module implements the HMAC algorithm described by RFC 2104 [https://datatracker.ietf.org/doc/html/rfc2104.html]. (Contributed by Gerhard Häring.)

Several functions that originally returned lengthy tuples now return pseudo-sequences that still behave like tuples but also have mnemonic attributes such as memberst_mtime or tm_year. The enhanced functions include stat(), fstat(), statvfs(), and fstatvfs() in the os module, and localtime(), gmtime(), and strptime() in the time module.

For example, to obtain a file’s size using the old tuples, you’d end up writing something like file_size = os.stat(filename)[stat.ST_SIZE], but now this can be written more clearly as file_size = os.stat(filename).st_size.

The original patch for this feature was contributed by Nick Mathewson.

The Python profiler has been extensively reworked and various errors in its output have been corrected. (Contributed by Fred L. Drake, Jr. and Tim Peters.)

The socket module can be compiled to support IPv6; specify the --enable-ipv6 option to Python’s configure script. (Contributed by Jun-ichiro “itojun” Hagino.)

Two new format characters were added to the struct module for 64-bit integers on platforms that support the C long long type. q is for a signed 64-bit integer, and Q is for an unsigned one. The value is returned in Python’s long integer type. (Contributed by Tim Peters.)

In the interpreter’s interactive mode, there’s a new built-in function help() that uses the pydoc module introduced in Python 2.1 to provide interactive help. help(object) displays any available help text about object. help() with no argument puts you in an online help utility, where you can enter the names of functions, classes, or modules to read their help text. (Contributed by Guido van Rossum, using Ka-Ping Yee’s pydoc module.)

Various bugfixes and performance improvements have been made to the SRE engine underlying the re module. For example, the re.sub() and re.split() functions have been rewritten in C. Another contributed patch speeds up certain Unicode character ranges by a factor of two, and a new finditer() method that returns an iterator over all the non-overlapping matches in a given string. (SRE is maintained by Fredrik Lundh. The BIGCHARSET patch was contributed by Martin von Löwis.)

The smtplib module now supports RFC 2487 [https://datatracker.ietf.org/doc/html/rfc2487.html], “Secure SMTP over TLS”, so it’s now possible to encrypt the SMTP traffic between a Python program and the mail transport agent being handed a message. smtplib also supports SMTP authentication. (Contributed by Gerhard Häring.)

The imaplib module, maintained by Piers Lauder, has support for several new extensions: the NAMESPACE extension defined in RFC 2342 [https://datatracker.ietf.org/doc/html/rfc2342.html], SORT, GETACL and SETACL. (Contributed by Anthony Baxter and Michel Pelletier.)

The rfc822 module’s parsing of email addresses is now compliant with RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html], an update to RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html]. (The module’s name is not going to be changed to rfc2822.) A new package, email, has also been added for parsing and generating e-mail messages. (Contributed by Barry Warsaw, and arising out of his work on Mailman.)

The difflib module now contains a new Differ class for producing human-readable lists of changes (a “delta”) between two sequences of lines of text. There are also two generator functions, ndiff() and restore(), which respectively return a delta from two sequences, or one of the original sequences from a delta. (Grunt work contributed by David Goodger, from ndiff.py code by Tim Peters who then did the generatorization.)

New constants ascii_letters, ascii_lowercase, and ascii_uppercase were added to the string module. There were several modules in the standard library that used string.letters to mean the ranges A-Za-z, but that assumption is incorrect when locales are in use, because string.letters varies depending on the set of legal characters defined by the current locale. The buggy modules have all been fixed to use ascii_letters instead. (Reported by an unknown person; fixed by Fred L. Drake, Jr.)

The mimetypes module now makes it easier to use alternative MIME-type databases by the addition of a MimeTypes class, which takes a list of filenames to be parsed. (Contributed by Fred L. Drake, Jr.)

A Timer class was added to the threading module that allows scheduling an activity to happen at some future time. (Contributed by Itamar Shtull-Trauring.)

Interpreter Changes and Fixes

Some of the changes only affect people who deal with the Python interpreter at the C level because they’re writing Python extension modules, embedding the interpreter, or just hacking on the interpreter itself. If you only write Python code, none of the changes described here will affect you very much.

Profiling and tracing functions can now be implemented in C, which can operate at much higher speeds than Python-based functions and should reduce the overhead of profiling and tracing. This will be of interest to authors of development environments for Python. Two new C functions were added to Python’s API, PyEval_SetProfile() and PyEval_SetTrace(). The existing sys.setprofile() and sys.settrace() functions still exist, and have simply been changed to use the new C-level interface. (Contributed by Fred L. Drake, Jr.)

Another low-level API, primarily of interest to implementers of Python debuggers and development tools, was added. PyInterpreterState_Head() and PyInterpreterState_Next() let a caller walk through all the existing interpreter objects; PyInterpreterState_ThreadHead() and PyThreadState_Next() allow looping over all the thread states for a given interpreter. (Contributed by David Beazley.)

The C-level interface to the garbage collector has been changed to make it easier to write extension types that support garbage collection and to debug misuses of the functions. Various functions have slightly different semantics, so a bunch of functions had to be renamed. Extensions that use the old API will still compile but will not participate in garbage collection, so updating them for 2.2 should be considered fairly high priority.

To upgrade an extension module to the new API, perform the following steps:

Rename Py_TPFLAGS_GC to Py_TPFLAGS_HAVE_GC.

Use PyObject_GC_New() or PyObject_GC_NewVar() to allocate

objects, and PyObject_GC_Del() to deallocate them.

Rename PyObject_GC_Init() to PyObject_GC_Track() and PyObject_GC_Fini() to PyObject_GC_UnTrack().

Remove PyGC_HEAD_SIZE from object size calculations.

Remove calls to PyObject_AS_GC() and PyObject_FROM_GC().

A new et format sequence was added to PyArg_ParseTuple(); et takes both a parameter and an encoding name, and converts the parameter to the given encoding if the parameter turns out to be a Unicode string, or leaves it alone if it’s an 8-bit string, assuming it to already be in the desired encoding. This differs from the es format character, which assumes that 8-bit strings are in Python’s default ASCII encoding and converts them to the specified new encoding. (Contributed by M.-A. Lemburg, and used for the MBCS support on Windows described in the following section.)

A different argument parsing function, PyArg_UnpackTuple(), has been added that’s simpler and presumably faster. Instead of specifying a format string, the caller simply gives the minimum and maximum number of arguments expected, and a set of pointers to PyObject* variables that will be filled in with argument values.

Two new flags METH_NOARGS and METH_O are available in method definition tables to simplify implementation of methods with no arguments or a single untyped argument. Calling such methods is more efficient than calling a corresponding method that uses METH_VARARGS. Also, the old METH_OLDARGS style of writing C methods is now officially deprecated.

Two new wrapper functions, PyOS_snprintf() and PyOS_vsnprintf() were added to provide cross-platform implementations for the relatively new snprintf() and vsnprintf() C lib APIs. In contrast to the standard sprintf() and vsprintf() functions, the Python versions check the bounds of the buffer used to protect against buffer overruns. (Contributed by M.-A. Lemburg.)

The _PyTuple_Resize() function has lost an unused parameter, so now it takes 2 parameters instead of 3. The third argument was never used, and can simply be discarded when porting code from earlier versions to Python 2.2.

Other Changes and Fixes

As usual there were a bunch of other improvements and bugfixes scattered throughout the source tree. A search through the CVS change logs finds there were 527 patches applied and 683 bugs fixed between Python 2.1 and 2.2; 2.2.1 applied 139 patches and fixed 143 bugs; 2.2.2 applied 106 patches and fixed 82 bugs. These figures are likely to be underestimates.

Some of the more notable changes are:

The code for the MacOS port for Python, maintained by Jack Jansen, is now kept in the main Python CVS tree, and many changes have been made to support MacOS X.

The most significant change is the ability to build Python as a framework, enabled by supplying the --enable-framework option to the configure script when compiling Python. According to Jack Jansen, “This installs a self-contained Python installation plus the OS X framework “glue” into /Library/Frameworks/Python.framework (or another location of choice). For now there is little immediate added benefit to this (actually, there is the disadvantage that you have to change your PATH to be able to find Python), but it is the basis for creating a full-blown Python application, porting the MacPython IDE, possibly using Python as a standard OSA scripting language and much more.”

Most of the MacPython toolbox modules, which interface to MacOS APIs such as windowing, QuickTime, scripting, etc. have been ported to OS X, but they’ve been left commented out in setup.py. People who want to experiment with these modules can uncomment them manually.

Keyword arguments passed to built-in functions that don’t take them now cause a TypeError exception to be raised, with the message “function takes no keyword arguments”.

Weak references, added in Python 2.1 as an extension module, are now part of the core because they’re used in the implementation of new-style classes. The ReferenceError exception has therefore moved from the weakref module to become a built-in exception.

A new script, Tools/scripts/cleanfuture.py by Tim Peters, automatically removes obsolete __future__ statements from Python source code.

An additional flags argument has been added to the built-in function compile(), so the behaviour of __future__ statements can now be correctly observed in simulated shells, such as those presented by IDLE and other development environments. This is described in PEP 264 [https://peps.python.org/pep-0264/]. (Contributed by Michael Hudson.)

The new license introduced with Python 1.6 wasn’t GPL-compatible. This is fixed by some minor textual changes to the 2.2 license, so it’s now legal to embed Python inside a GPLed program again. Note that Python itself is not GPLed, but instead is under a license that’s essentially equivalent to the BSD license, same as it always was. The license changes were also applied to the Python 2.0.1 and 2.1.1 releases.

When presented with a Unicode filename on Windows, Python will now convert it to an MBCS encoded string, as used by the Microsoft file APIs. As MBCS is explicitly used by the file APIs, Python’s choice of ASCII as the default encoding turns out to be an annoyance. On Unix, the locale’s character set is used if locale.nl_langinfo(CODESET) is available. (Windows support was contributed by Mark Hammond with assistance from Marc-André Lemburg. Unix support was added by Martin von Löwis.)

Large file support is now enabled on Windows. (Contributed by Tim Peters.)

The Tools/scripts/ftpmirror.py script now parses a .netrc file, if you have one. (Contributed by Mike Romberg.)

Some features of the object returned by the xrange() function are now deprecated, and trigger warnings when they’re accessed; they’ll disappear in Python 2.3. xrange objects tried to pretend they were full sequence types by supporting slicing, sequence multiplication, and the in operator, but these features were rarely used and therefore buggy. The tolist() method and the start, stop, and step attributes are also being deprecated. At the C level, the fourth argument to the PyRange_New() function, repeat, has also been deprecated.

There were a bunch of patches to the dictionary implementation, mostly to fix potential core dumps if a dictionary contains objects that sneakily changed their hash value, or mutated the dictionary they were contained in. For a while python-dev fell into a gentle rhythm of Michael Hudson finding a case that dumped core, Tim Peters fixing the bug, Michael finding another case, and round and round it went.

On Windows, Python can now be compiled with Borland C thanks to a number of patches contributed by Stephen Hansen, though the result isn’t fully functional yet. (But this is progress…)

Another Windows enhancement: Wise Solutions generously offered PythonLabs use of their InstallerMaster 8.1 system. Earlier PythonLabs Windows installers used Wise 5.0a, which was beginning to show its age. (Packaged up by Tim Peters.)

Files ending in .pyw can now be imported on Windows. .pyw is a Windows-only thing, used to indicate that a script needs to be run using PYTHONW.EXE instead of PYTHON.EXE in order to prevent a DOS console from popping up to display the output. This patch makes it possible to import such scripts, in case they’re also usable as modules. (Implemented by David Bolen.)

On platforms where Python uses the C dlopen() function to load extension modules, it’s now possible to set the flags used by dlopen() using the sys.getdlopenflags() and sys.setdlopenflags() functions. (Contributed by Bram Stolk.)

The pow() built-in function no longer supports 3 arguments when floating-point numbers are supplied. pow(x, y, z) returns (x**y) % z, but this is never useful for floating-point numbers, and the final result varies unpredictably depending on the platform. A call such as pow(2.0, 8.0, 7.0) will now raise a TypeError exception.

Acknowledgements

The author would like to thank the following people for offering suggestions, corrections and assistance with various drafts of this article: Fred Bremmer, Keith Briggs, Andrew Dalke, Fred L. Drake, Jr., Carel Fellinger, David Goodger, Mark Hammond, Stephen Hansen, Michael Hudson, Jack Jansen, Marc-André Lemburg, Martin von Löwis, Fredrik Lundh, Michael McLay, Nick Mathewson, Paul Moore, Gustavo Niemeyer, Don O’Donnell, Joonas Paalasma, Tim Peters, Jens Quade, Tom Reinhardt, Neil Schemenauer, Guido van Rossum, Greg Ward, Edward Welbourne.

What’s New in Python 2.1

Author:

A.M. Kuchling

Introduction

This article explains the new features in Python 2.1. While there aren’t as many changes in 2.1 as there were in Python 2.0, there are still some pleasant surprises in store. 2.1 is the first release to be steered through the use of Python Enhancement Proposals, or PEPs, so most of the sizable changes have accompanying PEPs that provide more complete documentation and a design rationale for the change. This article doesn’t attempt to document the new features completely, but simply provides an overview of the new features for Python programmers. Refer to the Python 2.1 documentation, or to the specific PEP, for more details about any new feature that particularly interests you.

One recent goal of the Python development team has been to accelerate the pace of new releases, with a new release coming every 6 to 9 months. 2.1 is the first release to come out at this faster pace, with the first alpha appearing in January, 3 months after the final version of 2.0 was released.

The final release of Python 2.1 was made on April 17, 2001.

PEP 227: Nested Scopes

The largest change in Python 2.1 is to Python’s scoping rules. In Python 2.0, at any given time there are at most three namespaces used to look up variable names: local, module-level, and the built-in namespace. This often surprised people because it didn’t match their intuitive expectations. For example, a nested recursive function definition doesn’t work:

def f():
    ...
    def g(value):
        ...
        return g(value-1) + 1
    ...

The function g() will always raise a NameError exception, because the binding of the name g isn’t in either its local namespace or in the module-level namespace. This isn’t much of a problem in practice (how often do you recursively define interior functions like this?), but this also made using the lambda expression clumsier, and this was a problem in practice. In code which uses lambda you can often find local variables being copied by passing them as the default values of arguments.

def find(self, name):
    "Return list of any entries equal to 'name'"
    L = filter(lambda x, name=name: x == name,
               self.list_attribute)
    return L

The readability of Python code written in a strongly functional style suffers greatly as a result.

The most significant change to Python 2.1 is that static scoping has been added to the language to fix this problem. As a first effect, the name=name default argument is now unnecessary in the above example. Put simply, when a given variable name is not assigned a value within a function (by an assignment, or the def, class, or import statements), references to the variable will be looked up in the local namespace of the enclosing scope. A more detailed explanation of the rules, and a dissection of the implementation, can be found in the PEP.

This change may cause some compatibility problems for code where the same variable name is used both at the module level and as a local variable within a function that contains further function definitions. This seems rather unlikely though, since such code would have been pretty confusing to read in the first place.

One side effect of the change is that the from module import * and exec statements have been made illegal inside a function scope under certain conditions. The Python reference manual has said all along that from module import * is only legal at the top level of a module, but the CPython interpreter has never enforced this before. As part of the implementation of nested scopes, the compiler which turns Python source into bytecodes has to generate different code to access variables in a containing scope. from module import * and exec make it impossible for the compiler to figure this out, because they add names to the local namespace that are unknowable at compile time. Therefore, if a function contains function definitions or lambda expressions with free variables, the compiler will flag this by raising a SyntaxError exception.

To make the preceding explanation a bit clearer, here’s an example:

x = 1
def f():
    # The next line is a syntax error
    exec 'x=2'
    def g():
        return x

Line 4 containing the exec statement is a syntax error, since exec would define a new local variable named x whose value should be accessed by g().

This shouldn’t be much of a limitation, since exec is rarely used in most Python code (and when it is used, it’s often a sign of a poor design anyway).

Compatibility concerns have led to nested scopes being introduced gradually; in Python 2.1, they aren’t enabled by default, but can be turned on within a module by using a future statement as described in PEP 236 [https://peps.python.org/pep-0236/]. (See the following section for further discussion of PEP 236 [https://peps.python.org/pep-0236/].) In Python 2.2, nested scopes will become the default and there will be no way to turn them off, but users will have had all of 2.1’s lifetime to fix any breakage resulting from their introduction.

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PEP 227 [https://peps.python.org/pep-0227/] - Statically Nested Scopes

Written and implemented by Jeremy Hylton.

PEP 236: __future__ Directives

The reaction to nested scopes was widespread concern about the dangers of breaking code with the 2.1 release, and it was strong enough to make the Pythoneers take a more conservative approach. This approach consists of introducing a convention for enabling optional functionality in release N that will become compulsory in release N+1.

The syntax uses a from...import statement using the reserved module name __future__. Nested scopes can be enabled by the following statement:

from __future__ import nested_scopes

While it looks like a normal import statement, it’s not; there are strict rules on where such a future statement can be put. They can only be at the top of a module, and must precede any Python code or regular import statements. This is because such statements can affect how the Python bytecode compiler parses code and generates bytecode, so they must precede any statement that will result in bytecodes being produced.

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PEP 236 [https://peps.python.org/pep-0236/] - Back to the __future__

Written by Tim Peters, and primarily implemented by Jeremy Hylton.

PEP 207: Rich Comparisons

In earlier versions, Python’s support for implementing comparisons on user-defined classes and extension types was quite simple. Classes could implement a __cmp__() method that was given two instances of a class, and could only return 0 if they were equal or +1 or -1 if they weren’t; the method couldn’t raise an exception or return anything other than a Boolean value. Users of Numeric Python often found this model too weak and restrictive, because in the number-crunching programs that numeric Python is used for, it would be more useful to be able to perform elementwise comparisons of two matrices, returning a matrix containing the results of a given comparison for each element. If the two matrices are of different sizes, then the compare has to be able to raise an exception to signal the error.

In Python 2.1, rich comparisons were added in order to support this need. Python classes can now individually overload each of the <, <=, >, >=, ==, and != operations. The new magic method names are:

Operation

Method name

<

__lt__()

<=

__le__()

>

__gt__()

>=

__ge__()

==

__eq__()

!=

__ne__()

(The magic methods are named after the corresponding Fortran operators .LT.. .LE., &c. Numeric programmers are almost certainly quite familiar with these names and will find them easy to remember.)

Each of these magic methods is of the form method(self, other), where self will be the object on the left-hand side of the operator, while other will be the object on the right-hand side. For example, the expression A < B will cause A.__lt__(B) to be called.

Each of these magic methods can return anything at all: a Boolean, a matrix, a list, or any other Python object. Alternatively they can raise an exception if the comparison is impossible, inconsistent, or otherwise meaningless.

The built-in cmp(A,B) function can use the rich comparison machinery, and now accepts an optional argument specifying which comparison operation to use; this is given as one of the strings "<", "<=", ">", ">=", "==", or "!=". If called without the optional third argument, cmp() will only return -1, 0, or +1 as in previous versions of Python; otherwise it will call the appropriate method and can return any Python object.

There are also corresponding changes of interest to C programmers; there’s a new slot tp_richcmp in type objects and an API for performing a given rich comparison. I won’t cover the C API here, but will refer you to PEP 207 [https://peps.python.org/pep-0207/], or to 2.1’s C API documentation, for the full list of related functions.

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PEP 207 [https://peps.python.org/pep-0207/] - Rich Comparisons

Written by Guido van Rossum, heavily based on earlier work by David Ascher, and implemented by Guido van Rossum.

PEP 230: Warning Framework

Over its 10 years of existence, Python has accumulated a certain number of obsolete modules and features along the way. It’s difficult to know when a feature is safe to remove, since there’s no way of knowing how much code uses it — perhaps no programs depend on the feature, or perhaps many do. To enable removing old features in a more structured way, a warning framework was added. When the Python developers want to get rid of a feature, it will first trigger a warning in the next version of Python. The following Python version can then drop the feature, and users will have had a full release cycle to remove uses of the old feature.

Python 2.1 adds the warning framework to be used in this scheme. It adds a warnings module that provide functions to issue warnings, and to filter out warnings that you don’t want to be displayed. Third-party modules can also use this framework to deprecate old features that they no longer wish to support.

For example, in Python 2.1 the regex module is deprecated, so importing it causes a warning to be printed:

>>> import regex
__main__:1: DeprecationWarning: the regex module
         is deprecated; please use the re module
>>>

Warnings can be issued by calling the warnings.warn() function:

warnings.warn("feature X no longer supported")

The first parameter is the warning message; an additional optional parameters can be used to specify a particular warning category.

Filters can be added to disable certain warnings; a regular expression pattern can be applied to the message or to the module name in order to suppress a warning. For example, you may have a program that uses the regex module and not want to spare the time to convert it to use the re module right now. The warning can be suppressed by calling

import warnings
warnings.filterwarnings(action = 'ignore',
                        message='.*regex module is deprecated',
                        category=DeprecationWarning,
                        module = '__main__')

This adds a filter that will apply only to warnings of the class DeprecationWarning triggered in the __main__ module, and applies a regular expression to only match the message about the regex module being deprecated, and will cause such warnings to be ignored. Warnings can also be printed only once, printed every time the offending code is executed, or turned into exceptions that will cause the program to stop (unless the exceptions are caught in the usual way, of course).

Functions were also added to Python’s C API for issuing warnings; refer to PEP 230 or to Python’s API documentation for the details.

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PEP 5 [https://peps.python.org/pep-0005/] - Guidelines for Language Evolution

Written by Paul Prescod, to specify procedures to be followed when removing old features from Python. The policy described in this PEP hasn’t been officially adopted, but the eventual policy probably won’t be too different from Prescod’s proposal.

PEP 230 [https://peps.python.org/pep-0230/] - Warning Framework

Written and implemented by Guido van Rossum.

PEP 229: New Build System

When compiling Python, the user had to go in and edit the Modules/Setup file in order to enable various additional modules; the default set is relatively small and limited to modules that compile on most Unix platforms. This means that on Unix platforms with many more features, most notably Linux, Python installations often don’t contain all useful modules they could.

Python 2.0 added the Distutils, a set of modules for distributing and installing extensions. In Python 2.1, the Distutils are used to compile much of the standard library of extension modules, autodetecting which ones are supported on the current machine. It’s hoped that this will make Python installations easier and more featureful.

Instead of having to edit the Modules/Setup file in order to enable modules, a setup.py script in the top directory of the Python source distribution is run at build time, and attempts to discover which modules can be enabled by examining the modules and header files on the system. If a module is configured in Modules/Setup, the setup.py script won’t attempt to compile that module and will defer to the Modules/Setup file’s contents. This provides a way to specific any strange command-line flags or libraries that are required for a specific platform.

In another far-reaching change to the build mechanism, Neil Schemenauer restructured things so Python now uses a single makefile that isn’t recursive, instead of makefiles in the top directory and in each of the Python/, Parser/, Objects/, and Modules/ subdirectories. This makes building Python faster and also makes hacking the Makefiles clearer and simpler.

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PEP 229 [https://peps.python.org/pep-0229/] - Using Distutils to Build Python

Written and implemented by A.M. Kuchling.

PEP 205: Weak References

Weak references, available through the weakref module, are a minor but useful new data type in the Python programmer’s toolbox.

Storing a reference to an object (say, in a dictionary or a list) has the side effect of keeping that object alive forever. There are a few specific cases where this behaviour is undesirable, object caches being the most common one, and another being circular references in data structures such as trees.

For example, consider a memoizing function that caches the results of another function f(x) by storing the function’s argument and its result in a dictionary:

_cache = {}
def memoize(x):
    if _cache.has_key(x):
        return _cache[x]

    retval = f(x)

    # Cache the returned object
    _cache[x] = retval

    return retval

This version works for simple things such as integers, but it has a side effect; the _cache dictionary holds a reference to the return values, so they’ll never be deallocated until the Python process exits and cleans up. This isn’t very noticeable for integers, but if f() returns an object, or a data structure that takes up a lot of memory, this can be a problem.

Weak references provide a way to implement a cache that won’t keep objects alive beyond their time. If an object is only accessible through weak references, the object will be deallocated and the weak references will now indicate that the object it referred to no longer exists. A weak reference to an object obj is created by calling wr = weakref.ref(obj). The object being referred to is returned by calling the weak reference as if it were a function: wr(). It will return the referenced object, or None if the object no longer exists.

This makes it possible to write a memoize() function whose cache doesn’t keep objects alive, by storing weak references in the cache.

_cache = {}
def memoize(x):
    if _cache.has_key(x):
        obj = _cache[x]()
        # If weak reference object still exists,
        # return it
        if obj is not None: return obj

    retval = f(x)

    # Cache a weak reference
    _cache[x] = weakref.ref(retval)

    return retval

The weakref module also allows creating proxy objects which behave like weak references — an object referenced only by proxy objects is deallocated – but instead of requiring an explicit call to retrieve the object, the proxy transparently forwards all operations to the object as long as the object still exists. If the object is deallocated, attempting to use a proxy will cause a weakref.ReferenceError exception to be raised.

proxy = weakref.proxy(obj)
proxy.attr   # Equivalent to obj.attr
proxy.meth() # Equivalent to obj.meth()
del obj
proxy.attr   # raises weakref.ReferenceError

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PEP 205 [https://peps.python.org/pep-0205/] - Weak References

Written and implemented by Fred L. Drake, Jr.

PEP 232: Function Attributes

In Python 2.1, functions can now have arbitrary information attached to them. People were often using docstrings to hold information about functions and methods, because the __doc__ attribute was the only way of attaching any information to a function. For example, in the Zope web application server, functions are marked as safe for public access by having a docstring, and in John Aycock’s SPARK parsing framework, docstrings hold parts of the BNF grammar to be parsed. This overloading is unfortunate, since docstrings are really intended to hold a function’s documentation; for example, it means you can’t properly document functions intended for private use in Zope.

Arbitrary attributes can now be set and retrieved on functions using the regular Python syntax:

def f(): pass

f.publish = 1
f.secure = 1
f.grammar = "A ::= B (C D)*"

The dictionary containing attributes can be accessed as the function’s __dict__. Unlike the __dict__ attribute of class instances, in functions you can actually assign a new dictionary to __dict__, though the new value is restricted to a regular Python dictionary; you can’t be tricky and set it to a UserDict instance, or any other random object that behaves like a mapping.

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PEP 232 [https://peps.python.org/pep-0232/] - Function Attributes

Written and implemented by Barry Warsaw.

PEP 235: Importing Modules on Case-Insensitive Platforms

Some operating systems have filesystems that are case-insensitive, MacOS and Windows being the primary examples; on these systems, it’s impossible to distinguish the filenames FILE.PY and file.py, even though they do store the file’s name in its original case (they’re case-preserving, too).

In Python 2.1, the import statement will work to simulate case-sensitivity on case-insensitive platforms. Python will now search for the first case-sensitive match by default, raising an ImportError if no such file is found, so import file will not import a module named FILE.PY. Case-insensitive matching can be requested by setting the PYTHONCASEOK environment variable before starting the Python interpreter.

PEP 217: Interactive Display Hook

When using the Python interpreter interactively, the output of commands is displayed using the built-in repr() function. In Python 2.1, the variable sys.displayhook() can be set to a callable object which will be called instead of repr(). For example, you can set it to a special pretty-printing function:

>>> # Create a recursive data structure
... L = [1,2,3]
>>> L.append(L)
>>> L # Show Python's default output
[1, 2, 3, [...]]
>>> # Use pprint.pprint() as the display function
... import sys, pprint
>>> sys.displayhook = pprint.pprint
>>> L
[1, 2, 3,  <Recursion on list with id=135143996>]
>>>

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PEP 217 [https://peps.python.org/pep-0217/] - Display Hook for Interactive Use

Written and implemented by Moshe Zadka.

PEP 208: New Coercion Model

How numeric coercion is done at the C level was significantly modified. This will only affect the authors of C extensions to Python, allowing them more flexibility in writing extension types that support numeric operations.

Extension types can now set the type flag Py_TPFLAGS_CHECKTYPES in their PyTypeObject structure to indicate that they support the new coercion model. In such extension types, the numeric slot functions can no longer assume that they’ll be passed two arguments of the same type; instead they may be passed two arguments of differing types, and can then perform their own internal coercion. If the slot function is passed a type it can’t handle, it can indicate the failure by returning a reference to the Py_NotImplemented singleton value. The numeric functions of the other type will then be tried, and perhaps they can handle the operation; if the other type also returns Py_NotImplemented, then a TypeError will be raised. Numeric methods written in Python can also return Py_NotImplemented, causing the interpreter to act as if the method did not exist (perhaps raising a TypeError, perhaps trying another object’s numeric methods).

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PEP 208 [https://peps.python.org/pep-0208/] - Reworking the Coercion Model

Written and implemented by Neil Schemenauer, heavily based upon earlier work by Marc-André Lemburg. Read this to understand the fine points of how numeric operations will now be processed at the C level.

PEP 241: Metadata in Python Packages

A common complaint from Python users is that there’s no single catalog of all the Python modules in existence. T. Middleton’s Vaults of Parnassus at www.vex.net/parnassus/ (retired in February 2009, available in the Internet Archive Wayback Machine [https://web.archive.org/web/20090130140102/http://www.vex.net/parnassus/]) was the largest catalog of Python modules, but registering software at the Vaults is optional, and many people did not bother.

As a first small step toward fixing the problem, Python software packaged using the Distutils sdist command will include a file named PKG-INFO containing information about the package such as its name, version, and author (metadata, in cataloguing terminology). PEP 241 [https://peps.python.org/pep-0241/] contains the full list of fields that can be present in the PKG-INFO file. As people began to package their software using Python 2.1, more and more packages will include metadata, making it possible to build automated cataloguing systems and experiment with them. With the result experience, perhaps it’ll be possible to design a really good catalog and then build support for it into Python 2.2. For example, the Distutils sdist and bdist_* commands could support an upload option that would automatically upload your package to a catalog server.

You can start creating packages containing PKG-INFO even if you’re not using Python 2.1, since a new release of the Distutils will be made for users of earlier Python versions. Version 1.0.2 of the Distutils includes the changes described in PEP 241 [https://peps.python.org/pep-0241/], as well as various bugfixes and enhancements. It will be available from the Distutils SIG at https://www.python.org/community/sigs/current/distutils-sig/.

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PEP 241 [https://peps.python.org/pep-0241/] - Metadata for Python Software Packages

Written and implemented by A.M. Kuchling.

PEP 243 [https://peps.python.org/pep-0243/] - Module Repository Upload Mechanism

Written by Sean Reifschneider, this draft PEP describes a proposed mechanism for uploading Python packages to a central server.

New and Improved Modules

Ka-Ping Yee contributed two new modules: inspect.py, a module for getting information about live Python code, and pydoc.py, a module for interactively converting docstrings to HTML or text. As a bonus, Tools/scripts/pydoc, which is now automatically installed, uses pydoc.py to display documentation given a Python module, package, or class name. For example, pydoc xml.dom displays the following:

Python Library Documentation: package xml.dom in xml

NAME
    xml.dom - W3C Document Object Model implementation for Python.

FILE
    /usr/local/lib/python2.1/xml/dom/__init__.pyc

DESCRIPTION
    The Python mapping of the Document Object Model is documented in the
    Python Library Reference in the section on the xml.dom package.

    This package contains the following modules:
      ...

pydoc also includes a Tk-based interactive help browser. pydoc quickly becomes addictive; try it out!

Two different modules for unit testing were added to the standard library. The doctest module, contributed by Tim Peters, provides a testing framework based on running embedded examples in docstrings and comparing the results against the expected output. PyUnit, contributed by Steve Purcell, is a unit testing framework inspired by JUnit, which was in turn an adaptation of Kent Beck’s Smalltalk testing framework. See https://pyunit.sourceforge.net/ for more information about PyUnit.

The difflib module contains a class, SequenceMatcher, which compares two sequences and computes the changes required to transform one sequence into the other. For example, this module can be used to write a tool similar to the Unix diff program, and in fact the sample program Tools/scripts/ndiff.py demonstrates how to write such a script.

curses.panel, a wrapper for the panel library, part of ncurses and of SYSV curses, was contributed by Thomas Gellekum. The panel library provides windows with the additional feature of depth. Windows can be moved higher or lower in the depth ordering, and the panel library figures out where panels overlap and which sections are visible.

The PyXML package has gone through a few releases since Python 2.0, and Python 2.1 includes an updated version of the xml package. Some of the noteworthy changes include support for Expat 1.2 and later versions, the ability for Expat parsers to handle files in any encoding supported by Python, and various bugfixes for SAX, DOM, and the minidom module.

Ping also contributed another hook for handling uncaught exceptions. sys.excepthook() can be set to a callable object. When an exception isn’t caught by any try…except blocks, the exception will be passed to sys.excepthook(), which can then do whatever it likes. At the Ninth Python Conference, Ping demonstrated an application for this hook: printing an extended traceback that not only lists the stack frames, but also lists the function arguments and the local variables for each frame.

Various functions in the time module, such as asctime() and localtime(), require a floating-point argument containing the time in seconds since the epoch. The most common use of these functions is to work with the current time, so the floating-point argument has been made optional; when a value isn’t provided, the current time will be used. For example, log file entries usually need a string containing the current time; in Python 2.1, time.asctime() can be used, instead of the lengthier time.asctime(time.localtime(time.time())) that was previously required.

This change was proposed and implemented by Thomas Wouters.

The ftplib module now defaults to retrieving files in passive mode, because passive mode is more likely to work from behind a firewall. This request came from the Debian bug tracking system, since other Debian packages use ftplib to retrieve files and then don’t work from behind a firewall. It’s deemed unlikely that this will cause problems for anyone, because Netscape defaults to passive mode and few people complain, but if passive mode is unsuitable for your application or network setup, call set_pasv(0) on FTP objects to disable passive mode.

Support for raw socket access has been added to the socket module, contributed by Grant Edwards.

The pstats module now contains a simple interactive statistics browser for displaying timing profiles for Python programs, invoked when the module is run as a script. Contributed by Eric S. Raymond.

A new implementation-dependent function, sys._getframe([depth]), has been added to return a given frame object from the current call stack. sys._getframe() returns the frame at the top of the call stack; if the optional integer argument depth is supplied, the function returns the frame that is depth calls below the top of the stack. For example, sys._getframe(1) returns the caller’s frame object.

This function is only present in CPython, not in Jython or the .NET implementation. Use it for debugging, and resist the temptation to put it into production code.

Other Changes and Fixes

There were relatively few smaller changes made in Python 2.1 due to the shorter release cycle. A search through the CVS change logs turns up 117 patches applied, and 136 bugs fixed; both figures are likely to be underestimates. Some of the more notable changes are:

A specialized object allocator is now optionally available, that should be faster than the system malloc() and have less memory overhead. The allocator uses C’s malloc() function to get large pools of memory, and then fulfills smaller memory requests from these pools. It can be enabled by providing the --with-pymalloc option to the configure script; see Objects/obmalloc.c for the implementation details.

Authors of C extension modules should test their code with the object allocator enabled, because some incorrect code may break, causing core dumps at runtime. There are a bunch of memory allocation functions in Python’s C API that have previously been just aliases for the C library’s malloc() and free(), meaning that if you accidentally called mismatched functions, the error wouldn’t be noticeable. When the object allocator is enabled, these functions aren’t aliases of malloc() and free() any more, and calling the wrong function to free memory will get you a core dump. For example, if memory was allocated using PyMem_New, it has to be freed using PyMem_Del(), not free(). A few modules included with Python fell afoul of this and had to be fixed; doubtless there are more third-party modules that will have the same problem.

The object allocator was contributed by Vladimir Marangozov.

The speed of line-oriented file I/O has been improved because people often complain about its lack of speed, and because it’s often been used as a naïve benchmark. The readline() method of file objects has therefore been rewritten to be much faster. The exact amount of the speedup will vary from platform to platform depending on how slow the C library’s getc() was, but is around 66%, and potentially much faster on some particular operating systems. Tim Peters did much of the benchmarking and coding for this change, motivated by a discussion in comp.lang.python.

A new module and method for file objects was also added, contributed by Jeff Epler. The new method, xreadlines(), is similar to the existing xrange() built-in. xreadlines() returns an opaque sequence object that only supports being iterated over, reading a line on every iteration but not reading the entire file into memory as the existing readlines() method does. You’d use it like this:

for line in sys.stdin.xreadlines():
    # ... do something for each line ...
    ...

For a fuller discussion of the line I/O changes, see the python-dev summary for January 1–15, 2001 at https://mail.python.org/pipermail/python-dev/2001-January/.

A new method, popitem(), was added to dictionaries to enable destructively iterating through the contents of a dictionary; this can be faster for large dictionaries because there’s no need to construct a list containing all the keys or values. D.popitem() removes a random (key, value) pair from the dictionary D and returns it as a 2-tuple. This was implemented mostly by Tim Peters and Guido van Rossum, after a suggestion and preliminary patch by Moshe Zadka.

Modules can now control which names are imported when from module import * is used, by defining an __all__ attribute containing a list of names that will be imported. One common complaint is that if the module imports other modules such as sys or string, from module import * will add them to the importing module’s namespace. To fix this, simply list the public names in __all__:

# List public names
__all__ = ['Database', 'open']

A stricter version of this patch was first suggested and implemented by Ben Wolfson, but after some python-dev discussion, a weaker final version was checked in.

Applying repr() to strings previously used octal escapes for non-printable characters; for example, a newline was '\012'. This was a vestigial trace of Python’s C ancestry, but today octal is of very little practical use. Ka-Ping Yee suggested using hex escapes instead of octal ones, and using the \n, \t, \r escapes for the appropriate characters, and implemented this new formatting.

Syntax errors detected at compile-time can now raise exceptions containing the filename and line number of the error, a pleasant side effect of the compiler reorganization done by Jeremy Hylton.

C extensions which import other modules have been changed to use PyImport_ImportModule(), which means that they will use any import hooks that have been installed. This is also encouraged for third-party extensions that need to import some other module from C code.

The size of the Unicode character database was shrunk by another 340K thanks to Fredrik Lundh.

Some new ports were contributed: MacOS X (by Steven Majewski), Cygwin (by Jason Tishler); RISCOS (by Dietmar Schwertberger); Unixware 7 (by Billy G. Allie).

And there’s the usual list of minor bugfixes, minor memory leaks, docstring edits, and other tweaks, too lengthy to be worth itemizing; see the CVS logs for the full details if you want them.

Acknowledgements

The author would like to thank the following people for offering suggestions on various drafts of this article: Graeme Cross, David Goodger, Jay Graves, Michael Hudson, Marc-André Lemburg, Fredrik Lundh, Neil Schemenauer, Thomas Wouters.

What’s New in Python 2.0

Author:

A.M. Kuchling and Moshe Zadka

Introduction

A new release of Python, version 2.0, was released on October 16, 2000. This article covers the exciting new features in 2.0, highlights some other useful changes, and points out a few incompatible changes that may require rewriting code.

Python’s development never completely stops between releases, and a steady flow of bug fixes and improvements are always being submitted. A host of minor fixes, a few optimizations, additional docstrings, and better error messages went into 2.0; to list them all would be impossible, but they’re certainly significant. Consult the publicly available CVS logs if you want to see the full list. This progress is due to the five developers working for PythonLabs are now getting paid to spend their days fixing bugs, and also due to the improved communication resulting from moving to SourceForge.

What About Python 1.6?

Python 1.6 can be thought of as the Contractual Obligations Python release. After the core development team left CNRI in May 2000, CNRI requested that a 1.6 release be created, containing all the work on Python that had been performed at CNRI. Python 1.6 therefore represents the state of the CVS tree as of May 2000, with the most significant new feature being Unicode support. Development continued after May, of course, so the 1.6 tree received a few fixes to ensure that it’s forward-compatible with Python 2.0. 1.6 is therefore part of Python’s evolution, and not a side branch.

So, should you take much interest in Python 1.6? Probably not. The 1.6final and 2.0beta1 releases were made on the same day (September 5, 2000), the plan being to finalize Python 2.0 within a month or so. If you have applications to maintain, there seems little point in breaking things by moving to 1.6, fixing them, and then having another round of breakage within a month by moving to 2.0; you’re better off just going straight to 2.0. Most of the really interesting features described in this document are only in 2.0, because a lot of work was done between May and September.

New Development Process

The most important change in Python 2.0 may not be to the code at all, but to how Python is developed: in May 2000 the Python developers began using the tools made available by SourceForge for storing source code, tracking bug reports, and managing the queue of patch submissions. To report bugs or submit patches for Python 2.0, use the bug tracking and patch manager tools available from Python’s project page, located at https://sourceforge.net/projects/python/.

The most important of the services now hosted at SourceForge is the Python CVS tree, the version-controlled repository containing the source code for Python. Previously, there were roughly 7 or so people who had write access to the CVS tree, and all patches had to be inspected and checked in by one of the people on this short list. Obviously, this wasn’t very scalable. By moving the CVS tree to SourceForge, it became possible to grant write access to more people; as of September 2000 there were 27 people able to check in changes, a fourfold increase. This makes possible large-scale changes that wouldn’t be attempted if they’d have to be filtered through the small group of core developers. For example, one day Peter Schneider-Kamp took it into his head to drop K&R C compatibility and convert the C source for Python to ANSI C. After getting approval on the python-dev mailing list, he launched into a flurry of checkins that lasted about a week, other developers joined in to help, and the job was done. If there were only 5 people with write access, probably that task would have been viewed as “nice, but not worth the time and effort needed” and it would never have gotten done.

The shift to using SourceForge’s services has resulted in a remarkable increase in the speed of development. Patches now get submitted, commented on, revised by people other than the original submitter, and bounced back and forth between people until the patch is deemed worth checking in. Bugs are tracked in one central location and can be assigned to a specific person for fixing, and we can count the number of open bugs to measure progress. This didn’t come without a cost: developers now have more e-mail to deal with, more mailing lists to follow, and special tools had to be written for the new environment. For example, SourceForge sends default patch and bug notification e-mail messages that are completely unhelpful, so Ka-Ping Yee wrote an HTML screen-scraper that sends more useful messages.

The ease of adding code caused a few initial growing pains, such as code was checked in before it was ready or without getting clear agreement from the developer group. The approval process that has emerged is somewhat similar to that used by the Apache group. Developers can vote +1, +0, -0, or -1 on a patch; +1 and -1 denote acceptance or rejection, while +0 and -0 mean the developer is mostly indifferent to the change, though with a slight positive or negative slant. The most significant change from the Apache model is that the voting is essentially advisory, letting Guido van Rossum, who has Benevolent Dictator For Life status, know what the general opinion is. He can still ignore the result of a vote, and approve or reject a change even if the community disagrees with him.

Producing an actual patch is the last step in adding a new feature, and is usually easy compared to the earlier task of coming up with a good design. Discussions of new features can often explode into lengthy mailing list threads, making the discussion hard to follow, and no one can read every posting to python-dev. Therefore, a relatively formal process has been set up to write Python Enhancement Proposals (PEPs), modelled on the internet RFC process. PEPs are draft documents that describe a proposed new feature, and are continually revised until the community reaches a consensus, either accepting or rejecting the proposal. Quoting from the introduction to PEP 1 [https://peps.python.org/pep-0001/], “PEP Purpose and Guidelines”:

PEP stands for Python Enhancement Proposal. A PEP is a design document providing information to the Python community, or describing a new feature for Python. The PEP should provide a concise technical specification of the feature and a rationale for the feature.

We intend PEPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Python. The PEP author is responsible for building consensus within the community and documenting dissenting opinions.

Read the rest of PEP 1 [https://peps.python.org/pep-0001/] for the details of the PEP editorial process, style, and format. PEPs are kept in the Python CVS tree on SourceForge, though they’re not part of the Python 2.0 distribution, and are also available in HTML form from https://peps.python.org/. As of September 2000, there are 25 PEPs, ranging from PEP 201 [https://peps.python.org/pep-0201/], “Lockstep Iteration”, to PEP 225, “Elementwise/Objectwise Operators”.

Unicode

The largest new feature in Python 2.0 is a new fundamental data type: Unicode strings. Unicode uses 16-bit numbers to represent characters instead of the 8-bit number used by ASCII, meaning that 65,536 distinct characters can be supported.

The final interface for Unicode support was arrived at through countless often-stormy discussions on the python-dev mailing list, and mostly implemented by Marc-André Lemburg, based on a Unicode string type implementation by Fredrik Lundh. A detailed explanation of the interface was written up as PEP 100 [https://peps.python.org/pep-0100/], “Python Unicode Integration”. This article will simply cover the most significant points about the Unicode interfaces.

In Python source code, Unicode strings are written as u"string". Arbitrary Unicode characters can be written using a new escape sequence, \uHHHH, where HHHH is a 4-digit hexadecimal number from 0000 to FFFF. The existing \xHH escape sequence can also be used, and octal escapes can be used for characters up to U+01FF, which is represented by \777.

Unicode strings, just like regular strings, are an immutable sequence type. They can be indexed and sliced, but not modified in place. Unicode strings have an encode( [encoding] ) method that returns an 8-bit string in the desired encoding. Encodings are named by strings, such as 'ascii', 'utf-8', 'iso-8859-1', or whatever. A codec API is defined for implementing and registering new encodings that are then available throughout a Python program. If an encoding isn’t specified, the default encoding is usually 7-bit ASCII, though it can be changed for your Python installation by calling the sys.setdefaultencoding(encoding) function in a customized version of site.py.

Combining 8-bit and Unicode strings always coerces to Unicode, using the default ASCII encoding; the result of 'a' + u'bc' is u'abc'.

New built-in functions have been added, and existing built-ins modified to support Unicode:

unichr(ch) returns a Unicode string 1 character long, containing the character ch.

ord(u), where u is a 1-character regular or Unicode string, returns the number of the character as an integer.

unicode(string [, encoding]  [, errors] ) creates a Unicode string from an 8-bit string. encoding is a string naming the encoding to use. The errors parameter specifies the treatment of characters that are invalid for the current encoding; passing 'strict' as the value causes an exception to be raised on any encoding error, while 'ignore' causes errors to be silently ignored and 'replace' uses U+FFFD, the official replacement character, in case of any problems.

The exec statement, and various built-ins such as eval(), getattr(), and setattr() will also accept Unicode strings as well as regular strings. (It’s possible that the process of fixing this missed some built-ins; if you find a built-in function that accepts strings but doesn’t accept Unicode strings at all, please report it as a bug.)

A new module, unicodedata, provides an interface to Unicode character properties. For example, unicodedata.category(u'A') returns the 2-character string ‘Lu’, the ‘L’ denoting it’s a letter, and ‘u’ meaning that it’s uppercase. unicodedata.bidirectional(u'\u0660') returns ‘AN’, meaning that U+0660 is an Arabic number.

The codecs module contains functions to look up existing encodings and register new ones. Unless you want to implement a new encoding, you’ll most often use the codecs.lookup(encoding) function, which returns a 4-element tuple: (encode_func, decode_func, stream_reader, stream_writer).

encode_func is a function that takes a Unicode string, and returns a 2-tuple (string, length). string is an 8-bit string containing a portion (perhaps all) of the Unicode string converted into the given encoding, and length tells you how much of the Unicode string was converted.

decode_func is the opposite of encode_func, taking an 8-bit string and returning a 2-tuple (ustring, length), consisting of the resulting Unicode string ustring and the integer length telling how much of the 8-bit string was consumed.

stream_reader is a class that supports decoding input from a stream. stream_reader(file_obj) returns an object that supports the read(), readline(), and readlines() methods. These methods will all translate from the given encoding and return Unicode strings.

stream_writer, similarly, is a class that supports encoding output to a stream. stream_writer(file_obj) returns an object that supports the write() and writelines() methods. These methods expect Unicode strings, translating them to the given encoding on output.

For example, the following code writes a Unicode string into a file, encoding it as UTF-8:

import codecs

unistr = u'\u0660\u2000ab ...'

(UTF8_encode, UTF8_decode,
 UTF8_streamreader, UTF8_streamwriter) = codecs.lookup('UTF-8')

output = UTF8_streamwriter( open( '/tmp/output', 'wb') )
output.write( unistr )
output.close()

The following code would then read UTF-8 input from the file:

input = UTF8_streamreader( open( '/tmp/output', 'rb') )
print repr(input.read())
input.close()

Unicode-aware regular expressions are available through the re module, which has a new underlying implementation called SRE written by Fredrik Lundh of Secret Labs AB.

A -U command line option was added which causes the Python compiler to interpret all string literals as Unicode string literals. This is intended to be used in testing and future-proofing your Python code, since some future version of Python may drop support for 8-bit strings and provide only Unicode strings.

List Comprehensions

Lists are a workhorse data type in Python, and many programs manipulate a list at some point. Two common operations on lists are to loop over them, and either pick out the elements that meet a certain criterion, or apply some function to each element. For example, given a list of strings, you might want to pull out all the strings containing a given substring, or strip off trailing whitespace from each line.

The existing map() and filter() functions can be used for this purpose, but they require a function as one of their arguments. This is fine if there’s an existing built-in function that can be passed directly, but if there isn’t, you have to create a little function to do the required work, and Python’s scoping rules make the result ugly if the little function needs additional information. Take the first example in the previous paragraph, finding all the strings in the list containing a given substring. You could write the following to do it:

# Given the list L, make a list of all strings
# containing the substring S.
sublist = filter( lambda s, substring=S:
                     string.find(s, substring) != -1,
                  L)

Because of Python’s scoping rules, a default argument is used so that the anonymous function created by the lambda expression knows what substring is being searched for. List comprehensions make this cleaner:

sublist = [ s for s in L if string.find(s, S) != -1 ]

List comprehensions have the form:

[ expression for expr in sequence1
             for expr2 in sequence2 ...
             for exprN in sequenceN
             if condition ]

The for…in clauses contain the sequences to be iterated over. The sequences do not have to be the same length, because they are not iterated over in parallel, but from left to right; this is explained more clearly in the following paragraphs. The elements of the generated list will be the successive values of expression. The final if clause is optional; if present, expression is only evaluated and added to the result if condition is true.

To make the semantics very clear, a list comprehension is equivalent to the following Python code:

for expr1 in sequence1:
    for expr2 in sequence2:
    ...
        for exprN in sequenceN:
             if (condition):
                  # Append the value of
                  # the expression to the
                  # resulting list.

This means that when there are multiple for…in clauses, the resulting list will be equal to the product of the lengths of all the sequences. If you have two lists of length 3, the output list is 9 elements long:

seq1 = 'abc'
seq2 = (1,2,3)
>>> [ (x,y) for x in seq1 for y in seq2]
[('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('b', 3), ('c', 1),
('c', 2), ('c', 3)]

To avoid introducing an ambiguity into Python’s grammar, if expression is creating a tuple, it must be surrounded with parentheses. The first list comprehension below is a syntax error, while the second one is correct:

# Syntax error
[ x,y for x in seq1 for y in seq2]
# Correct
[ (x,y) for x in seq1 for y in seq2]

The idea of list comprehensions originally comes from the functional programming language Haskell (https://www.haskell.org). Greg Ewing argued most effectively for adding them to Python and wrote the initial list comprehension patch, which was then discussed for a seemingly endless time on the python-dev mailing list and kept up-to-date by Skip Montanaro.

Augmented Assignment

Augmented assignment operators, another long-requested feature, have been added to Python 2.0. Augmented assignment operators include +=, -=, *=, and so forth. For example, the statement a += 2 increments the value of the variable a by 2, equivalent to the slightly lengthier a = a + 2.

The full list of supported assignment operators is +=, -=, *=, /=, %=, **=, &=, |=, ^=, >>=, and <<=. Python classes can override the augmented assignment operators by defining methods named __iadd__(), __isub__(), etc. For example, the following Number class stores a number and supports using += to create a new instance with an incremented value.

class Number:
    def __init__(self, value):
        self.value = value
    def __iadd__(self, increment):
        return Number( self.value + increment)

n = Number(5)
n += 3
print n.value

The __iadd__() special method is called with the value of the increment, and should return a new instance with an appropriately modified value; this return value is bound as the new value of the variable on the left-hand side.

Augmented assignment operators were first introduced in the C programming language, and most C-derived languages, such as awk, C++, Java, Perl, and PHP also support them. The augmented assignment patch was implemented by Thomas Wouters.

String Methods

Until now string-manipulation functionality was in the string module, which was usually a front-end for the strop module written in C. The addition of Unicode posed a difficulty for the strop module, because the functions would all need to be rewritten in order to accept either 8-bit or Unicode strings. For functions such as string.replace(), which takes 3 string arguments, that means eight possible permutations, and correspondingly complicated code.

Instead, Python 2.0 pushes the problem onto the string type, making string manipulation functionality available through methods on both 8-bit strings and Unicode strings.

>>> 'andrew'.capitalize()
'Andrew'
>>> 'hostname'.replace('os', 'linux')
'hlinuxtname'
>>> 'moshe'.find('sh')
2

One thing that hasn’t changed, a noteworthy April Fools’ joke notwithstanding, is that Python strings are immutable. Thus, the string methods return new strings, and do not modify the string on which they operate.

The old string module is still around for backwards compatibility, but it mostly acts as a front-end to the new string methods.

Two methods which have no parallel in pre-2.0 versions, although they did exist in JPython for quite some time, are startswith() and endswith(). s.startswith(t) is equivalent to s[:len(t)] == t, while s.endswith(t) is equivalent to s[-len(t):] == t.

One other method which deserves special mention is join(). The join() method of a string receives one parameter, a sequence of strings, and is equivalent to the string.join() function from the old string module, with the arguments reversed. In other words, s.join(seq) is equivalent to the old string.join(seq, s).

Garbage Collection of Cycles

The C implementation of Python uses reference counting to implement garbage collection. Every Python object maintains a count of the number of references pointing to itself, and adjusts the count as references are created or destroyed. Once the reference count reaches zero, the object is no longer accessible, since you need to have a reference to an object to access it, and if the count is zero, no references exist any longer.

Reference counting has some pleasant properties: it’s easy to understand and implement, and the resulting implementation is portable, fairly fast, and reacts well with other libraries that implement their own memory handling schemes. The major problem with reference counting is that it sometimes doesn’t realise that objects are no longer accessible, resulting in a memory leak. This happens when there are cycles of references.

Consider the simplest possible cycle, a class instance which has a reference to itself:

instance = SomeClass()
instance.myself = instance

After the above two lines of code have been executed, the reference count of instance is 2; one reference is from the variable named 'instance', and the other is from the myself attribute of the instance.

If the next line of code is del instance, what happens? The reference count of instance is decreased by 1, so it has a reference count of 1; the reference in the myself attribute still exists. Yet the instance is no longer accessible through Python code, and it could be deleted. Several objects can participate in a cycle if they have references to each other, causing all of the objects to be leaked.

Python 2.0 fixes this problem by periodically executing a cycle detection algorithm which looks for inaccessible cycles and deletes the objects involved. A new gc module provides functions to perform a garbage collection, obtain debugging statistics, and tuning the collector’s parameters.

Running the cycle detection algorithm takes some time, and therefore will result in some additional overhead. It is hoped that after we’ve gotten experience with the cycle collection from using 2.0, Python 2.1 will be able to minimize the overhead with careful tuning. It’s not yet obvious how much performance is lost, because benchmarking this is tricky and depends crucially on how often the program creates and destroys objects. The detection of cycles can be disabled when Python is compiled, if you can’t afford even a tiny speed penalty or suspect that the cycle collection is buggy, by specifying the --without-cycle-gc switch when running the configure script.

Several people tackled this problem and contributed to a solution. An early implementation of the cycle detection approach was written by Toby Kelsey. The current algorithm was suggested by Eric Tiedemann during a visit to CNRI, and Guido van Rossum and Neil Schemenauer wrote two different implementations, which were later integrated by Neil. Lots of other people offered suggestions along the way; the March 2000 archives of the python-dev mailing list contain most of the relevant discussion, especially in the threads titled “Reference cycle collection for Python” and “Finalization again”.

Other Core Changes

Various minor changes have been made to Python’s syntax and built-in functions. None of the changes are very far-reaching, but they’re handy conveniences.

Minor Language Changes

A new syntax makes it more convenient to call a given function with a tuple of arguments and/or a dictionary of keyword arguments. In Python 1.5 and earlier, you’d use the apply() built-in function: apply(f, args, kw) calls the function f() with the argument tuple args and the keyword arguments in the dictionary kw. apply() is the same in 2.0, but thanks to a patch from Greg Ewing, f(*args, **kw) is a shorter and clearer way to achieve the same effect. This syntax is symmetrical with the syntax for defining functions:

def f(*args, **kw):
    # args is a tuple of positional args,
    # kw is a dictionary of keyword args
    ...

The print statement can now have its output directed to a file-like object by following the print with >> file, similar to the redirection operator in Unix shells. Previously you’d either have to use the write() method of the file-like object, which lacks the convenience and simplicity of print, or you could assign a new value to sys.stdout and then restore the old value. For sending output to standard error, it’s much easier to write this:

print >> sys.stderr, "Warning: action field not supplied"

Modules can now be renamed on importing them, using the syntax import module as name or from module import name as othername. The patch was submitted by Thomas Wouters.

A new format style is available when using the % operator; ‘%r’ will insert the repr() of its argument. This was also added from symmetry considerations, this time for symmetry with the existing ‘%s’ format style, which inserts the str() of its argument. For example, '%r %s' % ('abc', 'abc') returns a string containing 'abc' abc.

Previously there was no way to implement a class that overrode Python’s built-in in operator and implemented a custom version. obj in seq returns true if obj is present in the sequence seq; Python computes this by simply trying every index of the sequence until either obj is found or an IndexError is encountered. Moshe Zadka contributed a patch which adds a __contains__() magic method for providing a custom implementation for in. Additionally, new built-in objects written in C can define what in means for them via a new slot in the sequence protocol.

Earlier versions of Python used a recursive algorithm for deleting objects. Deeply nested data structures could cause the interpreter to fill up the C stack and crash; Christian Tismer rewrote the deletion logic to fix this problem. On a related note, comparing recursive objects recursed infinitely and crashed; Jeremy Hylton rewrote the code to no longer crash, producing a useful result instead. For example, after this code:

a = []
b = []
a.append(a)
b.append(b)

The comparison a==b returns true, because the two recursive data structures are isomorphic. See the thread “trashcan and PR#7” in the April 2000 archives of the python-dev mailing list for the discussion leading up to this implementation, and some useful relevant links. Note that comparisons can now also raise exceptions. In earlier versions of Python, a comparison operation such as cmp(a,b) would always produce an answer, even if a user-defined __cmp__() method encountered an error, since the resulting exception would simply be silently swallowed.

Work has been done on porting Python to 64-bit Windows on the Itanium processor, mostly by Trent Mick of ActiveState. (Confusingly, sys.platform is still 'win32' on Win64 because it seems that for ease of porting, MS Visual C++ treats code as 32 bit on Itanium.) PythonWin also supports Windows CE; see the Python CE page at https://pythonce.sourceforge.net/ for more information.

Another new platform is Darwin/MacOS X; initial support for it is in Python 2.0. Dynamic loading works, if you specify “configure –with-dyld –with-suffix=.x”. Consult the README in the Python source distribution for more instructions.

An attempt has been made to alleviate one of Python’s warts, the often-confusing NameError exception when code refers to a local variable before the variable has been assigned a value. For example, the following code raises an exception on the print statement in both 1.5.2 and 2.0; in 1.5.2 a NameError exception is raised, while 2.0 raises a new UnboundLocalError exception. UnboundLocalError is a subclass of NameError, so any existing code that expects NameError to be raised should still work.

def f():
    print "i=",i
    i = i + 1
f()

Two new exceptions, TabError and IndentationError, have been introduced. They’re both subclasses of SyntaxError, and are raised when Python code is found to be improperly indented.

Changes to Built-in Functions

A new built-in, zip(seq1, seq2, ...), has been added. zip() returns a list of tuples where each tuple contains the i-th element from each of the argument sequences. The difference between zip() and map(None, seq1, seq2) is that map() pads the sequences with None if the sequences aren’t all of the same length, while zip() truncates the returned list to the length of the shortest argument sequence.

The int() and long() functions now accept an optional “base” parameter when the first argument is a string. int('123', 10) returns 123, while int('123', 16) returns 291. int(123, 16) raises a TypeError exception with the message “can’t convert non-string with explicit base”.

A new variable holding more detailed version information has been added to the sys module. sys.version_info is a tuple (major, minor, micro, level, serial) For example, in a hypothetical 2.0.1beta1, sys.version_info would be (2, 0, 1, 'beta', 1). level is a string such as "alpha", "beta", or "final" for a final release.

Dictionaries have an odd new method, setdefault(key, default), which behaves similarly to the existing get() method. However, if the key is missing, setdefault() both returns the value of default as get() would do, and also inserts it into the dictionary as the value for key. Thus, the following lines of code:

if dict.has_key( key ): return dict[key]
else:
    dict[key] = []
    return dict[key]

can be reduced to a single return dict.setdefault(key, []) statement.

The interpreter sets a maximum recursion depth in order to catch runaway recursion before filling the C stack and causing a core dump or GPF.. Previously this limit was fixed when you compiled Python, but in 2.0 the maximum recursion depth can be read and modified using sys.getrecursionlimit() and sys.setrecursionlimit(). The default value is 1000, and a rough maximum value for a given platform can be found by running a new script, Misc/find_recursionlimit.py.

Porting to 2.0

New Python releases try hard to be compatible with previous releases, and the record has been pretty good. However, some changes are considered useful enough, usually because they fix initial design decisions that turned out to be actively mistaken, that breaking backward compatibility can’t always be avoided. This section lists the changes in Python 2.0 that may cause old Python code to break.

The change which will probably break the most code is tightening up the arguments accepted by some methods. Some methods would take multiple arguments and treat them as a tuple, particularly various list methods such as append() and insert(). In earlier versions of Python, if L is a list, L.append( 1,2 ) appends the tuple (1,2) to the list. In Python 2.0 this causes a TypeError exception to be raised, with the message: ‘append requires exactly 1 argument; 2 given’. The fix is to simply add an extra set of parentheses to pass both values as a tuple: L.append( (1,2) ).

The earlier versions of these methods were more forgiving because they used an old function in Python’s C interface to parse their arguments; 2.0 modernizes them to use PyArg_ParseTuple(), the current argument parsing function, which provides more helpful error messages and treats multi-argument calls as errors. If you absolutely must use 2.0 but can’t fix your code, you can edit Objects/listobject.c and define the preprocessor symbol NO_STRICT_LIST_APPEND to preserve the old behaviour; this isn’t recommended.

Some of the functions in the socket module are still forgiving in this way. For example, socket.connect( ('hostname', 25) ) is the correct form, passing a tuple representing an IP address, but socket.connect('hostname', 25) also works. socket.connect_ex and socket.bind are similarly easy-going. 2.0alpha1 tightened these functions up, but because the documentation actually used the erroneous multiple argument form, many people wrote code which would break with the stricter checking. GvR backed out the changes in the face of public reaction, so for the socket module, the documentation was fixed and the multiple argument form is simply marked as deprecated; it will be tightened up again in a future Python version.

The \x escape in string literals now takes exactly 2 hex digits. Previously it would consume all the hex digits following the ‘x’ and take the lowest 8 bits of the result, so \x123456 was equivalent to \x56.

The AttributeError and NameError exceptions have a more friendly error message, whose text will be something like 'Spam' instance has no attribute 'eggs' or name 'eggs' is not defined. Previously the error message was just the missing attribute name eggs, and code written to take advantage of this fact will break in 2.0.

Some work has been done to make integers and long integers a bit more interchangeable. In 1.5.2, large-file support was added for Solaris, to allow reading files larger than 2 GiB; this made the tell() method of file objects return a long integer instead of a regular integer. Some code would subtract two file offsets and attempt to use the result to multiply a sequence or slice a string, but this raised a TypeError. In 2.0, long integers can be used to multiply or slice a sequence, and it’ll behave as you’d intuitively expect it to; 3L * 'abc' produces ‘abcabcabc’, and (0,1,2,3)[2L:4L] produces (2,3). Long integers can also be used in various contexts where previously only integers were accepted, such as in the seek() method of file objects, and in the formats supported by the % operator (%d, %i, %x, etc.). For example, "%d" % 2L**64 will produce the string 18446744073709551616.

The subtlest long integer change of all is that the str() of a long integer no longer has a trailing ‘L’ character, though repr() still includes it. The ‘L’ annoyed many people who wanted to print long integers that looked just like regular integers, since they had to go out of their way to chop off the character. This is no longer a problem in 2.0, but code which does str(longval)[:-1] and assumes the ‘L’ is there, will now lose the final digit.

Taking the repr() of a float now uses a different formatting precision than str(). repr() uses %.17g format string for C’s sprintf(), while str() uses %.12g as before. The effect is that repr() may occasionally show more decimal places than str(), for certain numbers. For example, the number 8.1 can’t be represented exactly in binary, so repr(8.1) is '8.0999999999999996', while str(8.1) is '8.1'.

The -X command-line option, which turned all standard exceptions into strings instead of classes, has been removed; the standard exceptions will now always be classes. The exceptions module containing the standard exceptions was translated from Python to a built-in C module, written by Barry Warsaw and Fredrik Lundh.

Extending/Embedding Changes

Some of the changes are under the covers, and will only be apparent to people writing C extension modules or embedding a Python interpreter in a larger application. If you aren’t dealing with Python’s C API, you can safely skip this section.

The version number of the Python C API was incremented, so C extensions compiled for 1.5.2 must be recompiled in order to work with 2.0. On Windows, it’s not possible for Python 2.0 to import a third party extension built for Python 1.5.x due to how Windows DLLs work, so Python will raise an exception and the import will fail.

Users of Jim Fulton’s ExtensionClass module will be pleased to find out that hooks have been added so that ExtensionClasses are now supported by isinstance() and issubclass(). This means you no longer have to remember to write code such as if type(obj) == myExtensionClass, but can use the more natural if isinstance(obj, myExtensionClass).

The Python/importdl.c file, which was a mass of #ifdefs to support dynamic loading on many different platforms, was cleaned up and reorganised by Greg Stein. importdl.c is now quite small, and platform-specific code has been moved into a bunch of Python/dynload_*.c files. Another cleanup: there were also a number of my*.h files in the Include/ directory that held various portability hacks; they’ve been merged into a single file, Include/pyport.h.

Vladimir Marangozov’s long-awaited malloc restructuring was completed, to make it easy to have the Python interpreter use a custom allocator instead of C’s standard malloc(). For documentation, read the comments in Include/pymem.h and Include/objimpl.h. For the lengthy discussions during which the interface was hammered out, see the web archives of the ‘patches’ and ‘python-dev’ lists at python.org.

Recent versions of the GUSI development environment for MacOS support POSIX threads. Therefore, Python’s POSIX threading support now works on the Macintosh. Threading support using the user-space GNU pth library was also contributed.

Threading support on Windows was enhanced, too. Windows supports thread locks that use kernel objects only in case of contention; in the common case when there’s no contention, they use simpler functions which are an order of magnitude faster. A threaded version of Python 1.5.2 on NT is twice as slow as an unthreaded version; with the 2.0 changes, the difference is only 10%. These improvements were contributed by Yakov Markovitch.

Python 2.0’s source now uses only ANSI C prototypes, so compiling Python now requires an ANSI C compiler, and can no longer be done using a compiler that only supports K&R C.

Previously the Python virtual machine used 16-bit numbers in its bytecode, limiting the size of source files. In particular, this affected the maximum size of literal lists and dictionaries in Python source; occasionally people who are generating Python code would run into this limit. A patch by Charles G. Waldman raises the limit from 2**16 to 2**32.

Three new convenience functions intended for adding constants to a module’s dictionary at module initialization time were added: PyModule_AddObject(), PyModule_AddIntConstant(), and PyModule_AddStringConstant(). Each of these functions takes a module object, a null-terminated C string containing the name to be added, and a third argument for the value to be assigned to the name. This third argument is, respectively, a Python object, a C long, or a C string.

A wrapper API was added for Unix-style signal handlers. PyOS_getsig() gets a signal handler and PyOS_setsig() will set a new handler.

Distutils: Making Modules Easy to Install

Before Python 2.0, installing modules was a tedious affair – there was no way to figure out automatically where Python is installed, or what compiler options to use for extension modules. Software authors had to go through an arduous ritual of editing Makefiles and configuration files, which only really work on Unix and leave Windows and MacOS unsupported. Python users faced wildly differing installation instructions which varied between different extension packages, which made administering a Python installation something of a chore.

The SIG for distribution utilities, shepherded by Greg Ward, has created the Distutils, a system to make package installation much easier. They form the distutils package, a new part of Python’s standard library. In the best case, installing a Python module from source will require the same steps: first you simply mean unpack the tarball or zip archive, and the run “python setup.py install”. The platform will be automatically detected, the compiler will be recognized, C extension modules will be compiled, and the distribution installed into the proper directory. Optional command-line arguments provide more control over the installation process, the distutils package offers many places to override defaults – separating the build from the install, building or installing in non-default directories, and more.

In order to use the Distutils, you need to write a setup.py script. For the simple case, when the software contains only .py files, a minimal setup.py can be just a few lines long:

from distutils.core import setup
setup (name = "foo", version = "1.0",
       py_modules = ["module1", "module2"])

The setup.py file isn’t much more complicated if the software consists of a few packages:

from distutils.core import setup
setup (name = "foo", version = "1.0",
       packages = ["package", "package.subpackage"])

A C extension can be the most complicated case; here’s an example taken from the PyXML package:

from distutils.core import setup, Extension

expat_extension = Extension('xml.parsers.pyexpat',
     define_macros = [('XML_NS', None)],
     include_dirs = [ 'extensions/expat/xmltok',
                      'extensions/expat/xmlparse' ],
     sources = [ 'extensions/pyexpat.c',
                 'extensions/expat/xmltok/xmltok.c',
                 'extensions/expat/xmltok/xmlrole.c', ]
       )
setup (name = "PyXML", version = "0.5.4",
       ext_modules =[ expat_extension ] )

The Distutils can also take care of creating source and binary distributions. The “sdist” command, run by “python setup.py sdist’, builds a source distribution such as foo-1.0.tar.gz. Adding new commands isn’t difficult, “bdist_rpm” and “bdist_wininst” commands have already been contributed to create an RPM distribution and a Windows installer for the software, respectively. Commands to create other distribution formats such as Debian packages and Solaris .pkg files are in various stages of development.

All this is documented in a new manual, Distributing Python Modules, that joins the basic set of Python documentation.

XML Modules

Python 1.5.2 included a simple XML parser in the form of the xmllib module, contributed by Sjoerd Mullender. Since 1.5.2’s release, two different interfaces for processing XML have become common: SAX2 (version 2 of the Simple API for XML) provides an event-driven interface with some similarities to xmllib, and the DOM (Document Object Model) provides a tree-based interface, transforming an XML document into a tree of nodes that can be traversed and modified. Python 2.0 includes a SAX2 interface and a stripped-down DOM interface as part of the xml package. Here we will give a brief overview of these new interfaces; consult the Python documentation or the source code for complete details. The Python XML SIG is also working on improved documentation.

SAX2 Support

SAX defines an event-driven interface for parsing XML. To use SAX, you must write a SAX handler class. Handler classes inherit from various classes provided by SAX, and override various methods that will then be called by the XML parser. For example, the startElement() and endElement() methods are called for every starting and end tag encountered by the parser, the characters() method is called for every chunk of character data, and so forth.

The advantage of the event-driven approach is that the whole document doesn’t have to be resident in memory at any one time, which matters if you are processing really huge documents. However, writing the SAX handler class can get very complicated if you’re trying to modify the document structure in some elaborate way.

For example, this little example program defines a handler that prints a message for every starting and ending tag, and then parses the file hamlet.xml using it:

from xml import sax

class SimpleHandler(sax.ContentHandler):
    def startElement(self, name, attrs):
        print 'Start of element:', name, attrs.keys()

    def endElement(self, name):
        print 'End of element:', name

# Create a parser object
parser = sax.make_parser()

# Tell it what handler to use
handler = SimpleHandler()
parser.setContentHandler( handler )

# Parse a file!
parser.parse( 'hamlet.xml' )

For more information, consult the Python documentation, or the XML HOWTO at https://pyxml.sourceforge.net/topics/howto/xml-howto.html.

DOM Support

The Document Object Model is a tree-based representation for an XML document. A top-level Document instance is the root of the tree, and has a single child which is the top-level Element instance. This Element has children nodes representing character data and any sub-elements, which may have further children of their own, and so forth. Using the DOM you can traverse the resulting tree any way you like, access element and attribute values, insert and delete nodes, and convert the tree back into XML.

The DOM is useful for modifying XML documents, because you can create a DOM tree, modify it by adding new nodes or rearranging subtrees, and then produce a new XML document as output. You can also construct a DOM tree manually and convert it to XML, which can be a more flexible way of producing XML output than simply writing <tag1>…</tag1> to a file.

The DOM implementation included with Python lives in the xml.dom.minidom module. It’s a lightweight implementation of the Level 1 DOM with support for XML namespaces. The parse() and parseString() convenience functions are provided for generating a DOM tree:

from xml.dom import minidom
doc = minidom.parse('hamlet.xml')

doc is a Document instance. Document, like all the other DOM classes such as Element and Text, is a subclass of the Node base class. All the nodes in a DOM tree therefore support certain common methods, such as toxml() which returns a string containing the XML representation of the node and its children. Each class also has special methods of its own; for example, Element and Document instances have a method to find all child elements with a given tag name. Continuing from the previous 2-line example:

perslist = doc.getElementsByTagName( 'PERSONA' )
print perslist[0].toxml()
print perslist[1].toxml()

For the Hamlet XML file, the above few lines output:

<PERSONA>CLAUDIUS, king of Denmark. </PERSONA>
<PERSONA>HAMLET, son to the late, and nephew to the present king.</PERSONA>

The root element of the document is available as doc.documentElement, and its children can be easily modified by deleting, adding, or removing nodes:

root = doc.documentElement

# Remove the first child
root.removeChild( root.childNodes[0] )

# Move the new first child to the end
root.appendChild( root.childNodes[0] )

# Insert the new first child (originally,
# the third child) before the 20th child.
root.insertBefore( root.childNodes[0], root.childNodes[20] )

Again, I will refer you to the Python documentation for a complete listing of the different Node classes and their various methods.

Relationship to PyXML

The XML Special Interest Group has been working on XML-related Python code for a while. Its code distribution, called PyXML, is available from the SIG’s web pages at https://www.python.org/community/sigs/current/xml-sig. The PyXML distribution also used the package name xml. If you’ve written programs that used PyXML, you’re probably wondering about its compatibility with the 2.0 xml package.

The answer is that Python 2.0’s xml package isn’t compatible with PyXML, but can be made compatible by installing a recent version PyXML. Many applications can get by with the XML support that is included with Python 2.0, but more complicated applications will require that the full PyXML package will be installed. When installed, PyXML versions 0.6.0 or greater will replace the xml package shipped with Python, and will be a strict superset of the standard package, adding a bunch of additional features. Some of the additional features in PyXML include:

4DOM, a full DOM implementation from FourThought, Inc.

The xmlproc validating parser, written by Lars Marius Garshol.

The sgmlop parser accelerator module, written by Fredrik Lundh.

Module changes

Lots of improvements and bugfixes were made to Python’s extensive standard library; some of the affected modules include readline, ConfigParser, cgi, calendar, posix, readline, xmllib, aifc, chunk, wave, random, shelve, and nntplib. Consult the CVS logs for the exact patch-by-patch details.

Brian Gallew contributed OpenSSL support for the socket module. OpenSSL is an implementation of the Secure Socket Layer, which encrypts the data being sent over a socket. When compiling Python, you can edit Modules/Setup to include SSL support, which adds an additional function to the socket module: socket.ssl(socket, keyfile, certfile), which takes a socket object and returns an SSL socket. The httplib and urllib modules were also changed to support https:// URLs, though no one has implemented FTP or SMTP over SSL.

The httplib module has been rewritten by Greg Stein to support HTTP/1.1.

Backward compatibility with the 1.5 version of httplib is provided, though using HTTP/1.1 features such as pipelining will require rewriting code to use a different set of interfaces.

The Tkinter module now supports Tcl/Tk version 8.1, 8.2, or 8.3, and support for the older 7.x versions has been dropped. The Tkinter module now supports displaying Unicode strings in Tk widgets. Also, Fredrik Lundh contributed an optimization which makes operations like create_line and create_polygon much faster, especially when using lots of coordinates.

The curses module has been greatly extended, starting from Oliver Andrich’s enhanced version, to provide many additional functions from ncurses and SYSV curses, such as colour, alternative character set support, pads, and mouse support. This means the module is no longer compatible with operating systems that only have BSD curses, but there don’t seem to be any currently maintained OSes that fall into this category.

As mentioned in the earlier discussion of 2.0’s Unicode support, the underlying implementation of the regular expressions provided by the re module has been changed. SRE, a new regular expression engine written by Fredrik Lundh and partially funded by Hewlett Packard, supports matching against both 8-bit strings and Unicode strings.

New modules

A number of new modules were added. We’ll simply list them with brief descriptions; consult the 2.0 documentation for the details of a particular module.

atexit: For registering functions to be called before the Python interpreter exits. Code that currently sets sys.exitfunc directly should be changed to use the atexit module instead, importing atexit and calling atexit.register() with the function to be called on exit. (Contributed by Skip Montanaro.)

codecs, encodings, unicodedata: Added as part of the new Unicode support.

filecmp: Supersedes the old cmp, cmpcache and dircmp modules, which have now become deprecated. (Contributed by Gordon MacMillan and Moshe Zadka.)

gettext: This module provides internationalization (I18N) and localization (L10N) support for Python programs by providing an interface to the GNU gettext message catalog library. (Integrated by Barry Warsaw, from separate contributions by Martin von Löwis, Peter Funk, and James Henstridge.)

linuxaudiodev: Support for the /dev/audio device on Linux, a twin to the existing sunaudiodev module. (Contributed by Peter Bosch, with fixes by Jeremy Hylton.)

mmap: An interface to memory-mapped files on both Windows and Unix. A file’s contents can be mapped directly into memory, at which point it behaves like a mutable string, so its contents can be read and modified. They can even be passed to functions that expect ordinary strings, such as the re module. (Contributed by Sam Rushing, with some extensions by A.M. Kuchling.)

pyexpat: An interface to the Expat XML parser. (Contributed by Paul Prescod.)

robotparser: Parse a robots.txt file, which is used for writing web spiders that politely avoid certain areas of a web site. The parser accepts the contents of a robots.txt file, builds a set of rules from it, and can then answer questions about the fetchability of a given URL. (Contributed by Skip Montanaro.)

tabnanny: A module/script to check Python source code for ambiguous indentation. (Contributed by Tim Peters.)

UserString: A base class useful for deriving objects that behave like strings.

webbrowser: A module that provides a platform independent way to launch a web browser on a specific URL. For each platform, various browsers are tried in a specific order. The user can alter which browser is launched by setting the BROWSER environment variable. (Originally inspired by Eric S. Raymond’s patch to urllib which added similar functionality, but the final module comes from code originally implemented by Fred Drake as Tools/idle/BrowserControl.py, and adapted for the standard library by Fred.)

_winreg: An interface to the Windows registry. _winreg is an adaptation of functions that have been part of PythonWin since 1995, but has now been added to the core distribution, and enhanced to support Unicode. _winreg was written by Bill Tutt and Mark Hammond.

zipfile: A module for reading and writing ZIP-format archives. These are archives produced by PKZIP on DOS/Windows or zip on Unix, not to be confused with gzip-format files (which are supported by the gzip module) (Contributed by James C. Ahlstrom.)

imputil: A module that provides a simpler way for writing customized import hooks, in comparison to the existing ihooks module. (Implemented by Greg Stein, with much discussion on python-dev along the way.)

IDLE Improvements

IDLE is the official Python cross-platform IDE, written using Tkinter. Python 2.0 includes IDLE 0.6, which adds a number of new features and improvements. A partial list:

UI improvements and optimizations, especially in the area of syntax highlighting and auto-indentation.

The class browser now shows more information, such as the top level functions in a module.

Tab width is now a user settable option. When opening an existing Python file, IDLE automatically detects the indentation conventions, and adapts.

There is now support for calling browsers on various platforms, used to open the Python documentation in a browser.

IDLE now has a command line, which is largely similar to the vanilla Python interpreter.

Call tips were added in many places.

IDLE can now be installed as a package.

In the editor window, there is now a line/column bar at the bottom.

Three new keystroke commands: Check module (Alt-F5), Import module (F5) and Run script (Ctrl-F5).

Deleted and Deprecated Modules

A few modules have been dropped because they’re obsolete, or because there are now better ways to do the same thing. The stdwin module is gone; it was for a platform-independent windowing toolkit that’s no longer developed.

A number of modules have been moved to the lib-old subdirectory: cmp, cmpcache, dircmp, dump, find, grep, packmail, poly, util, whatsound, zmod. If you have code which relies on a module that’s been moved to lib-old, you can simply add that directory to sys.path to get them back, but you’re encouraged to update any code that uses these modules.

Acknowledgements

The authors would like to thank the following people for offering suggestions on various drafts of this article: David Bolen, Mark Hammond, Gregg Hauser, Jeremy Hylton, Fredrik Lundh, Detlef Lannert, Aahz Maruch, Skip Montanaro, Vladimir Marangozov, Tobias Polzin, Guido van Rossum, Neil Schemenauer, and Russ Schmidt.

Changelog

Python next

Release date: XXXX-XX-XX

Windows

gh-125729 [https://github.com/python/cpython/issues/125729]: Makes the presence of the turtle module dependent on the Tcl/Tk installer option. Previously, the module was always installed but would be unusable without Tcl/Tk.

Tools/Demos

gh-126700 [https://github.com/python/cpython/issues/126700]: Add support for multi-argument gettext functions in pygettext.py.

Tests

gh-127076 [https://github.com/python/cpython/issues/127076]: Disable strace based system call tests when LD_PRELOAD is set.

gh-127076 [https://github.com/python/cpython/issues/127076]: Filter out memory-related mmap, munmap, and mprotect calls from file-related ones when testing io behavior using strace.

Library

gh-127072 [https://github.com/python/cpython/issues/127072]: Remove outdated socket.NETLINK_* constants not present in Linux kernels beyond 2.6.17.

gh-127182 [https://github.com/python/cpython/issues/127182]: Fix io.StringIO.__setstate__() crash, when None was passed as the first value.

gh-127217 [https://github.com/python/cpython/issues/127217]: Fix urllib.request.pathname2url() for paths starting with multiple slashes on Posix.

gh-125866 [https://github.com/python/cpython/issues/125866]: urllib.request.pathname2url() now adds an empty authority when generating a URL for a path that begins with exactly one slash. For example, the path /etc/hosts is converted to the scheme-less URL ///etc/hosts. As a result of this change, URLs without authorities are only generated for relative paths.

gh-127035 [https://github.com/python/cpython/issues/127035]: Fix shutil.which on Windows. Now it looks at direct match if and only if the command ends with a PATHEXT extension or X_OK is not in mode. Support extensionless files if “.” is in PATHEXT. Support PATHEXT extensions that end with a dot.

gh-122273 [https://github.com/python/cpython/issues/122273]: Support PyREPL history on Windows. Patch by devdanzin and Victor Stinner.

gh-125866 [https://github.com/python/cpython/issues/125866]: urllib.request.pathname2url() and url2pathname() no longer convert Windows drive letters to uppercase.

gh-127078 [https://github.com/python/cpython/issues/127078]: Fix issue where urllib.request.url2pathname() failed to discard an extra slash before a UNC drive in the URL path on Windows.

gh-126766 [https://github.com/python/cpython/issues/126766]: Fix issue where urllib.request.url2pathname() failed to discard any ‘localhost’ authority present in the URL.

gh-127065 [https://github.com/python/cpython/issues/127065]: Fix crash when calling a operator.methodcaller() instance from multiple threads in the free threading build.

gh-126997 [https://github.com/python/cpython/issues/126997]: Fix support of STRING and GLOBAL opcodes with non-ASCII arguments in pickletools. pickletools.dis() now outputs non-ASCII bytes in STRING, BINSTRING and SHORT_BINSTRING arguments as escaped (\xXX).

gh-126316 [https://github.com/python/cpython/issues/126316]: grp: Make grp.getgrall() thread-safe by adding a mutex. Patch by Victor Stinner.

gh-126615 [https://github.com/python/cpython/issues/126615]: The COMError exception is now public. Previously, this was private and only available in _ctypes.

gh-126985 [https://github.com/python/cpython/issues/126985]: When running under a virtual environment with the site disabled (see -S), sys.prefix and sys.base_prefix will now point to the virtual environment, instead of the base installation.

gh-118761 [https://github.com/python/cpython/issues/118761]: Improve import time of mimetypes by around 11-16 times. Patch by Hugo van Kemenade.

gh-126947 [https://github.com/python/cpython/issues/126947]: Raise TypeError in _pydatetime.timedelta.__new__() if the passed arguments are not int or float, so that the Python implementation is in line with the C implementation.

gh-126946 [https://github.com/python/cpython/issues/126946]: Improve the GetoptError error message when a long option prefix matches multiple accepted options in getopt.getopt() and getopt.gnu_getopt().

gh-85168 [https://github.com/python/cpython/issues/85168]: Fix issue where urllib.request.url2pathname() and pathname2url() always used UTF-8 when quoting and unquoting file URIs. They now use the filesystem encoding and error handler.

gh-126780 [https://github.com/python/cpython/issues/126780]: Fix os.path.normpath() for drive-relative paths on Windows.

gh-126601 [https://github.com/python/cpython/issues/126601]: Fix issue where urllib.request.pathname2url() raised OSError when given a Windows path containing a colon character not following a drive letter, such as before an NTFS alternate data stream.

gh-126727 [https://github.com/python/cpython/issues/126727]: locale.nl_langinfo(locale.ERA) now returns multiple era description segments separated by semicolons. Previously it only returned the first segment on platforms with Glibc.

gh-118201 [https://github.com/python/cpython/issues/118201]: Fixed intermittent failures of os.confstr, os.pathconf and os.sysconf on iOS and Android.

gh-86463 [https://github.com/python/cpython/issues/86463]: The usage parameter of argparse.ArgumentParser no longer affects the default value of the prog parameter in subparsers.

gh-122356 [https://github.com/python/cpython/issues/122356]: Guarantee that the position of a file-like object passed to zipfile.is_zipfile() is left untouched after the call. Patch by Bénédikt Tran.

gh-88110 [https://github.com/python/cpython/issues/88110]: Fixed multiprocessing.Process reporting a .exitcode of 1 even on success when using the "fork" start method while using a concurrent.futures.ThreadPoolExecutor.

gh-97514 [https://github.com/python/cpython/issues/97514]: Authentication was added to the multiprocessing forkserver start method control socket so that only processes with the authentication key generated by the process that spawned the forkserver can control it. This is an enhancement over the other gh-97514 [https://github.com/python/cpython/issues/97514] fixes so that access is no longer limited only by filesystem permissions.

The file descriptor exchange of control pipes with the forked worker process now requires an explicit acknowledgement byte to be sent over the socket after the exchange on all forkserver supporting platforms. That makes testing the above much easier.

Core and Builtins

gh-127238 [https://github.com/python/cpython/issues/127238]: Correct error message for sys.set_int_max_str_digits().

gh-113841 [https://github.com/python/cpython/issues/113841]: Fix possible undefined behavior division by zero in complex’s _Py_c_pow().

gh-127133 [https://github.com/python/cpython/issues/127133]: Calling argparse.ArgumentParser.add_argument_group() on an argument group, and calling argparse.ArgumentParser.add_argument_group() or argparse.ArgumentParser.add_mutually_exclusive_group() on a mutually exclusive group now raise exceptions. This nesting was never supported, often failed to work correctly, and was unintentionally exposed through inheritance. This functionality has been deprecated since Python 3.11.

gh-127020 [https://github.com/python/cpython/issues/127020]: Fix a crash in the free threading build when PyCode_GetCode(), PyCode_GetVarnames(), PyCode_GetCellvars(), or PyCode_GetFreevars() were called from multiple threads at the same time.

gh-127010 [https://github.com/python/cpython/issues/127010]: Simplify GC tracking of dictionaries. All dictionaries are tracked when created, rather than being lazily tracked when a trackable object was added to them. This simplifies the code considerably and results in a slight speedup.

gh-126980 [https://github.com/python/cpython/issues/126980]: Fix __buffer__() of bytearray crashing when READ or WRITE are passed as flags.

gh-126892 [https://github.com/python/cpython/issues/126892]: Require cold or invalidated code to “warm up” before being JIT compiled again.

gh-126091 [https://github.com/python/cpython/issues/126091]: Ensure stack traces are complete when throwing into a generator chain that ends in a custom generator.

gh-124470 [https://github.com/python/cpython/issues/124470]: Fix crash in free-threaded builds when replacing object dictionary while reading attribute on another thread

gh-69639 [https://github.com/python/cpython/issues/69639]: Implement mixed-mode arithmetic rules combining real and complex numbers as specified by C standards since C99. Patch by Sergey B Kirpichev.

gh-109746 [https://github.com/python/cpython/issues/109746]: If _thread.start_new_thread() fails to start a new thread, it deletes its state from interpreter and thus avoids its repeated cleanup on finalization.

C API

gh-121058 [https://github.com/python/cpython/issues/121058]: PyThreadState_Clear() now warns (and calls sys.excepthook) if the thread state still has an active exception.

Build

gh-115869 [https://github.com/python/cpython/issues/115869]: Make jit_stencils.h (which is produced during JIT builds) reproducible.

gh-126898 [https://github.com/python/cpython/issues/126898]: The Emscripten build of Python is now based on ES6 modules.

Python 3.14.0 alpha 2

Release date: 2024-11-19

Windows

gh-126911 [https://github.com/python/cpython/issues/126911]: Update credits command output.

gh-118973 [https://github.com/python/cpython/issues/118973]: Ensures the experimental free-threaded install includes the _tkinter module. The optional Tcl/Tk component must also be installed in order for the module to work.

gh-126497 [https://github.com/python/cpython/issues/126497]: Fixes venv failure due to missing redirector executables in experimental free-threaded installs.

gh-126074 [https://github.com/python/cpython/issues/126074]: Removed unnecessary DLLs from Windows embeddable package

gh-125315 [https://github.com/python/cpython/issues/125315]: Avoid crashing in platform due to slow WMI calls on some Windows machines.

gh-126084 [https://github.com/python/cpython/issues/126084]: Fix venvwlauncher to launch pythonw instead of python so no extra console window is created.

gh-125842 [https://github.com/python/cpython/issues/125842]: Fix a SystemError when sys.exit() is called with 0xffffffff on Windows.

gh-125550 [https://github.com/python/cpython/issues/125550]: Enable the 윈도우 용 파이썬 런처 to detect Python 3.14 installs from the Windows Store.

gh-123803 [https://github.com/python/cpython/issues/123803]: All Windows code pages are now supported as “cpXXX” codecs on Windows.

Tools/Demos

gh-126807 [https://github.com/python/cpython/issues/126807]: Fix extraction warnings in pygettext.py caused by mistaking function definitions for function calls.

gh-126167 [https://github.com/python/cpython/issues/126167]: The iOS testbed was modified so that it can be used by third-party projects for testing purposes.

Tests

gh-126909 [https://github.com/python/cpython/issues/126909]: Fix test_os extended attribute tests to work on filesystems with 1 KiB xattr size limit.

gh-125730 [https://github.com/python/cpython/issues/125730]: Change make test to not run GUI tests by default. Use make ci to run tests with GUI tests instead.

gh-124295 [https://github.com/python/cpython/issues/124295]: Add translation tests to the argparse module.

Security

gh-126623 [https://github.com/python/cpython/issues/126623]: Upgrade libexpat to 2.6.4

Library

gh-85957 [https://github.com/python/cpython/issues/85957]: Add missing MIME types for images with RFCs: emf, fits, g3fax, jp2, jpm, jpx, t38, tiff-fx and wmf. Patch by Hugo van Kemenade.

gh-126920 [https://github.com/python/cpython/issues/126920]: Fix the prefix and exec_prefix keys from sysconfig.get_config_vars() incorrectly having the same value as sys.base_prefix and sys.base_exec_prefix, respectively, inside virtual environments. They now accurately reflect sys.prefix and sys.exec_prefix.

gh-67877 [https://github.com/python/cpython/issues/67877]: Fix memory leaks when regular expression matching terminates abruptly, either because of a signal or because memory allocation fails.

gh-125063 [https://github.com/python/cpython/issues/125063]: marshal now supports slice objects. The marshal format version was increased to 5.

gh-126789 [https://github.com/python/cpython/issues/126789]: Fixed the values of sysconfig.get_config_vars(), sysconfig.get_paths(), and their siblings when the site initialization happens after sysconfig has built a cache for sysconfig.get_config_vars().

gh-126188 [https://github.com/python/cpython/issues/126188]: Update bundled pip to 24.3.1

gh-126766 [https://github.com/python/cpython/issues/126766]: Fix issue where urllib.request.url2pathname() failed to discard two leading slashes introducing an empty authority section.

gh-126705 [https://github.com/python/cpython/issues/126705]: Allow os.PathLike to be a base for Protocols.

gh-126699 [https://github.com/python/cpython/issues/126699]: Allow collections.abc.AsyncIterator to be a base for Protocols.

gh-126654 [https://github.com/python/cpython/issues/126654]: Fix crash when non-dict was passed to several functions in _interpreters module.

gh-104745 [https://github.com/python/cpython/issues/104745]: Limit starting a patcher (from unittest.mock.patch() or unittest.mock.patch.object()) more than once without stopping it

gh-126595 [https://github.com/python/cpython/issues/126595]: Fix a crash when instantiating itertools.count with an initial count of sys.maxsize on debug builds. Patch by Bénédikt Tran.

gh-120423 [https://github.com/python/cpython/issues/120423]: Fix issue where urllib.request.pathname2url() mishandled Windows paths with embedded forward slashes.

gh-126565 [https://github.com/python/cpython/issues/126565]: Improve performances of zipfile.Path.open() for non-reading modes.

gh-126505 [https://github.com/python/cpython/issues/126505]: Fix bugs in compiling case-insensitive regular expressions with character classes containing non-BMP characters: upper-case non-BMP character did was ignored and the ASCII flag was ignored when matching a character range whose upper bound is beyond the BMP region.

gh-117378 [https://github.com/python/cpython/issues/117378]: Fixed the multiprocessing "forkserver" start method forkserver process to correctly inherit the parent’s sys.path during the importing of multiprocessing.set_forkserver_preload() modules in the same manner as sys.path is configured in workers before executing work items.

This bug caused some forkserver module preloading to silently fail to preload. This manifested as a performance degration in child processes when the sys.path was required due to additional repeated work in every worker.

It could also have a side effect of "" remaining in sys.path during forkserver preload imports instead of the absolute path from os.getcwd() at multiprocessing import time used in the worker sys.path.

The sys.path differences between phases in the child process could potentially have caused preload to import incorrect things from the wrong location. We are unaware of that actually having happened in practice.

gh-125679 [https://github.com/python/cpython/issues/125679]: The multiprocessing.Lock and multiprocessing.RLock repr values no longer say “unknown” on macOS.

gh-126476 [https://github.com/python/cpython/issues/126476]: Raise calendar.IllegalMonthError (now a subclass of IndexError) for calendar.month() when the input month is not correct.

gh-126489 [https://github.com/python/cpython/issues/126489]: The Python implementation of pickle no longer calls pickle.Pickler.persistent_id() for the result of persistent_id().

gh-126451 [https://github.com/python/cpython/issues/126451]: Register the contextvars.Context type to collections.abc.Mapping.

gh-126175 [https://github.com/python/cpython/issues/126175]: Add msg, doc, pos, lineno and colno attributes to tomllib.TOMLDecodeError. Deprecate instantiating with free-form arguments.

gh-89416 [https://github.com/python/cpython/issues/89416]: Add RFC 9559 [https://datatracker.ietf.org/doc/html/rfc9559.html] MIME types for Matroska audiovisual container formats. Patch by Hugo van Kemenade.

gh-126417 [https://github.com/python/cpython/issues/126417]: Register the multiprocessing.managers.DictProxy and multiprocessing.managers.ListProxy types in multiprocessing.managers to collections.abc.MutableMapping and collections.abc.MutableSequence, respectively.

gh-126390 [https://github.com/python/cpython/issues/126390]: Add support for returning intermixed options and non-option arguments in order in getopt.gnu_getopt().

gh-126374 [https://github.com/python/cpython/issues/126374]: Add support for options with optional arguments in the getopt module.

gh-126363 [https://github.com/python/cpython/issues/126363]: Speed up pattern parsing in pathlib.Path.glob() by skipping creation of a pathlib.Path object for the pattern.

gh-126353 [https://github.com/python/cpython/issues/126353]: asyncio.get_event_loop() now does not implicitly creates an event loop. It now raises a RuntimeError if there is no set event loop. Patch by Kumar Aditya.

gh-126313 [https://github.com/python/cpython/issues/126313]: Fix an issue in curses.napms() when curses.initscr() has not yet been called. Patch by Bénédikt Tran.

gh-126303 [https://github.com/python/cpython/issues/126303]: Fix pickling and copying of os.sched_param objects.

gh-126138 [https://github.com/python/cpython/issues/126138]: Fix a use-after-free crash on asyncio.Task objects whose underlying coroutine yields an object that implements an evil __getattribute__(). Patch by Nico Posada.

gh-120057 [https://github.com/python/cpython/issues/120057]: Replace the os.environ.refresh() method with a new os.reload_environ() function. Patch by Victor Stinner.

gh-126220 [https://github.com/python/cpython/issues/126220]: Fix crash in cProfile.Profile and _lsprof.Profiler when their callbacks were directly called with 0 arguments.

gh-126212 [https://github.com/python/cpython/issues/126212]: Fix issue where urllib.request.pathname2url() and url2pathname() removed slashes from Windows DOS drive paths and URLs.

gh-126223 [https://github.com/python/cpython/issues/126223]: Raise a UnicodeEncodeError instead of a SystemError upon calling _interpreters.create() with an invalid Unicode character.

gh-126205 [https://github.com/python/cpython/issues/126205]: Fix issue where urllib.request.pathname2url() generated URLs beginning with four slashes (rather than two) when given a Windows UNC path.

gh-126156 [https://github.com/python/cpython/issues/126156]: Improved performances of creating Morsel objects by a factor of 3.8x.

gh-126105 [https://github.com/python/cpython/issues/126105]: Fix a crash in ast when the ast.AST._fields attribute is deleted.

gh-126106 [https://github.com/python/cpython/issues/126106]: Fixes a possible NULL pointer dereference in ssl.

gh-126080 [https://github.com/python/cpython/issues/126080]: Fix a use-after-free crash on asyncio.Task objects for which the underlying event loop implements an evil __getattribute__(). Reported by Nico-Posada. Patch by Bénédikt Tran.

gh-125322 [https://github.com/python/cpython/issues/125322]: Correct detection of complex numbers support in libffi.

gh-126083 [https://github.com/python/cpython/issues/126083]: Fixed a reference leak in asyncio.Task objects when reinitializing the same object with a non-None context. Patch by Nico Posada.

gh-126068 [https://github.com/python/cpython/issues/126068]: Fix exceptions in the argparse module so that only error messages for ArgumentError and ArgumentTypeError are now translated. ArgumentError is now only used for command line errors, not for logical errors in the program. TypeError is now raised instead of ValueError for some logical errors.

gh-125413 [https://github.com/python/cpython/issues/125413]: Add pathlib.Path.scandir() method to efficiently fetch directory children and their file attributes. This is a trivial wrapper of os.scandir().

gh-125984 [https://github.com/python/cpython/issues/125984]: Fix use-after-free crashes on asyncio.Future objects for which the underlying event loop implements an evil __getattribute__(). Reported by Nico-Posada. Patch by Bénédikt Tran.

gh-125926 [https://github.com/python/cpython/issues/125926]: Fix urllib.parse.urljoin() for base URI with undefined authority. Although RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html] only specify reference resolution for absolute base URI, urljoin() should continue to return sensible result for relative base URI.

gh-125969 [https://github.com/python/cpython/issues/125969]: Fix an out-of-bounds crash when an evil asyncio.loop.call_soon() mutates the length of the internal callbacks list. Patch by Bénédikt Tran.

gh-125966 [https://github.com/python/cpython/issues/125966]: Fix a use-after-free crash in asyncio.Future.remove_done_callback(). Patch by Bénédikt Tran.

gh-125789 [https://github.com/python/cpython/issues/125789]: Fix possible crash when mutating list of callbacks returned by asyncio.Future._callbacks. It now always returns a new copy in C implementation _asyncio. Patch by Kumar Aditya.

gh-126916 [https://github.com/python/cpython/issues/126916]: Allow the initial parameter of functools.reduce() to be passed as a keyword argument. Patch by Sayandip Dutta.

gh-124452 [https://github.com/python/cpython/issues/124452]: Fix an issue in email.policy.EmailPolicy.header_source_parse() and email.policy.Compat32.header_source_parse() that introduced spurious leading whitespaces into header values when the header includes a newline character after the header name delimiter (:) and before the value.

gh-117941 [https://github.com/python/cpython/issues/117941]: argparse.BooleanOptionalAction now rejects option names starting with --no-.

gh-125884 [https://github.com/python/cpython/issues/125884]: Fixed the bug for pdb where it can’t set breakpoints on functions with certain annotations.

gh-125355 [https://github.com/python/cpython/issues/125355]: Fix several bugs in argparse.ArgumentParser.parse_intermixed_args().

The parser no longer changes temporarily during parsing.

Default values are not processed twice.

Required mutually exclusive groups containing positional arguments are now supported.

The missing arguments report now includes the names of all required optional and positional arguments.

Unknown options can be intermixed with positional arguments in parse_known_intermixed_args().

gh-125767 [https://github.com/python/cpython/issues/125767]: super objects are now pickleable and copyable.

gh-124969 [https://github.com/python/cpython/issues/124969]: locale.nl_langinfo(locale.ALT_DIGITS) now returns a string again. The returned value consists of up to 100 semicolon-separated symbols.

gh-84850 [https://github.com/python/cpython/issues/84850]: Remove URLopener and FancyURLopener classes from urllib.request. They had previously raised DeprecationWarning since Python 3.3.

gh-125666 [https://github.com/python/cpython/issues/125666]: Avoid the exiting the interpreter if a null byte is given as input in the new REPL.

gh-125710 [https://github.com/python/cpython/issues/125710]: [Enum] fix hashable<->nonhashable comparisons for member values

gh-125631 [https://github.com/python/cpython/issues/125631]: Restore ability to set persistent_id and persistent_load attributes of instances of the Pickler and Unpickler classes in the pickle module.

gh-125378 [https://github.com/python/cpython/issues/125378]: Fixed the bug in pdb where after a multi-line command, an empty line repeats the first line of the multi-line command, instead of the full command.

gh-125682 [https://github.com/python/cpython/issues/125682]: Reject non-ASCII digits in the Python implementation of json.loads() conforming to the JSON specification.

gh-125660 [https://github.com/python/cpython/issues/125660]: Reject invalid unicode escapes for Python implementation of json.loads().

gh-52551 [https://github.com/python/cpython/issues/52551]: Use wcsftime() to implement time.strftime() on Windows.

gh-125259 [https://github.com/python/cpython/issues/125259]: Fix the notes removal logic for errors thrown in enum initialization.

gh-125633 [https://github.com/python/cpython/issues/125633]: Add function inspect.ispackage() to determine whether an object is a package or not.

gh-125614 [https://github.com/python/cpython/issues/125614]: In the FORWARDREF format of annotationlib, fix bug where nested expressions were not returned as annotationlib.ForwardRef format.

gh-125590 [https://github.com/python/cpython/issues/125590]: Allow FrameLocalsProxy to delete and pop if the key is not a fast variable.

gh-125600 [https://github.com/python/cpython/issues/125600]: Only show stale code warning in pdb when we display source code.

gh-125542 [https://github.com/python/cpython/issues/125542]: Deprecate passing keyword-only prefix_chars argument to argparse.ArgumentParser.add_argument_group().

gh-125541 [https://github.com/python/cpython/issues/125541]: Pressing Ctrl-C while blocked in threading.Lock.acquire(), threading.RLock.acquire(), and threading.Thread.join() now interrupts the function call and raises a KeyboardInterrupt exception on Windows, similar to how those functions behave on macOS and Linux.

gh-125519 [https://github.com/python/cpython/issues/125519]: Improve traceback if importlib.reload() is called with an object that is not a module. Patch by Alex Waygood.

gh-125451 [https://github.com/python/cpython/issues/125451]: Fix deadlock when concurrent.futures.ProcessPoolExecutor shuts down concurrently with an error when feeding a job to a worker process.

gh-125115 [https://github.com/python/cpython/issues/125115]: Fixed a bug in pdb where arguments starting with - can’t be passed to the debugged script.

gh-125398 [https://github.com/python/cpython/issues/125398]: Fix the conversion of the VIRTUAL_ENV path in the activate script in venv when running in Git Bash for Windows.

gh-125245 [https://github.com/python/cpython/issues/125245]: Fix race condition when importing collections.abc, which could incorrectly return an empty module.

gh-52551 [https://github.com/python/cpython/issues/52551]: Fix encoding issues in time.strftime(), the strftime() method of the datetime classes datetime, date and time and formatting of these classes. Characters not encodable in the current locale are now acceptable in the format string. Surrogate pairs and sequence of surrogatescape-encoded bytes are no longer recombinated. Embedded null character no longer terminates the format string.

gh-124984 [https://github.com/python/cpython/issues/124984]: Fixed thread safety in ssl in the free-threaded build. OpenSSL operations are now protected by a per-object lock.

gh-124651 [https://github.com/python/cpython/issues/124651]: Properly quote template strings in venv activation scripts.

gh-124694 [https://github.com/python/cpython/issues/124694]: We’ve added concurrent.futures.InterpreterPoolExecutor, which allows you to run code in multiple isolated interpreters. This allows you to circumvent the limitations of CPU-bound threads (due to the GIL). Patch by Eric Snow.

This addition is unrelated to PEP 734 [https://peps.python.org/pep-0734/].

gh-58032 [https://github.com/python/cpython/issues/58032]: Deprecate the argparse.FileType type converter.

gh-99749 [https://github.com/python/cpython/issues/99749]: Adds a feature to optionally enable suggestions for argument choices and subparser names if mistyped by the user.

gh-58956 [https://github.com/python/cpython/issues/58956]: Fixed a bug in pdb where sometimes the breakpoint won’t trigger if it was set on a function which is already in the call stack.

gh-124111 [https://github.com/python/cpython/issues/124111]: The tkinter module can now be built to use either the new version 9.0.0 of Tcl/Tk or the latest release 8.6.15 of Tcl/Tk 8. Tcl/Tk 9 includes many improvements, both to the Tcl language and to the appearance and utility of the graphical user interface provided by Tk.

gh-80958 [https://github.com/python/cpython/issues/80958]: unittest discovery supports PEP 420 namespace packages as start directory again.

gh-123370 [https://github.com/python/cpython/issues/123370]: Fix the canvas not clearing after running turtledemo clock.

gh-89083 [https://github.com/python/cpython/issues/89083]: Add uuid.uuid8() for generating UUIDv8 objects as specified in RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html]. Patch by Bénédikt Tran

gh-122549 [https://github.com/python/cpython/issues/122549]: Add platform.invalidate_caches() to invalidate cached results.

gh-120754 [https://github.com/python/cpython/issues/120754]: Update unbounded read calls in zipfile to specify an explicit size putting a limit on how much data they may read. This also updates handling around ZIP max comment size to match the standard instead of reading comments that are one byte too long.

gh-121267 [https://github.com/python/cpython/issues/121267]: Improve the performance of tarfile when writing files, by caching user names and group names.

gh-70764 [https://github.com/python/cpython/issues/70764]: Fixed an issue where inspect.getclosurevars() would incorrectly classify an attribute name as a global variable when the name exists both as an attribute name and a global variable.

gh-118289 [https://github.com/python/cpython/issues/118289]: posixpath.realpath() now raises NotADirectoryError when strict mode is enabled and a non-directory path with a trailing slash is supplied.

gh-119826 [https://github.com/python/cpython/issues/119826]: Always return an absolute path for os.path.abspath() on Windows.

gh-97850 [https://github.com/python/cpython/issues/97850]: Remove deprecated pkgutil.get_loader() and pkgutil.find_loader().

gh-118986 [https://github.com/python/cpython/issues/118986]: Add socket.IPV6_RECVERR constant (available since Linux 2.2).

gh-116897 [https://github.com/python/cpython/issues/116897]: Accepting objects with false values (like 0 and []) except empty strings, byte-like objects and None in urllib.parse functions parse_qsl() and parse_qs() is now deprecated.

gh-101955 [https://github.com/python/cpython/issues/101955]: Fix SystemError when match regular expression pattern containing some combination of possessive quantifier, alternative and capture group.

gh-71936 [https://github.com/python/cpython/issues/71936]: Fix a race condition in multiprocessing.pool.Pool.

bpo-46128 [https://bugs.python.org/issue?@action=redirect&bpo=46128]: Strip unittest.IsolatedAsyncioTestCase stack frames from reported stacktraces.

gh-84852 [https://github.com/python/cpython/issues/84852]: Add MIME types for MS Embedded OpenType, OpenType Layout, TrueType, WOFF 1.0 and 2.0 fonts. Patch by Sahil Prajapati and Hugo van Kemenade.

Documentation

gh-126622 [https://github.com/python/cpython/issues/126622]: Added stub pages for removed modules explaining their removal, where to find replacements, and linking to the last Python version that supported them. Contributed by Ned Batchelder.

gh-125277 [https://github.com/python/cpython/issues/125277]: Require Sphinx 7.2.6 or later to build the Python documentation. Patch by Adam Turner.

gh-60712 [https://github.com/python/cpython/issues/60712]: Include the object type in the lists of documented types. Change by Furkan Onder and Martin Panter.

Core and Builtins

gh-126795 [https://github.com/python/cpython/issues/126795]: Increase the threshold for JIT code warmup. Depending on platform and workload, this can result in performance gains of 1-9% and memory savings of 3-5%.

gh-126341 [https://github.com/python/cpython/issues/126341]: Now ValueError is raised instead of SystemError when trying to iterate over a released memoryview object.

gh-126688 [https://github.com/python/cpython/issues/126688]: Fix a crash when calling os.fork() on some operating systems, including SerenityOS.

gh-126066 [https://github.com/python/cpython/issues/126066]: Fix importlib to not write an incomplete .pyc files when a ulimit or some other operating system mechanism is preventing the write to go through fully.

gh-126222 [https://github.com/python/cpython/issues/126222]: Do not include count of “peek” items in _PyUop_num_popped. This ensures that the correct number of items are popped from the stack when a micro-op exits with an error.

gh-126366 [https://github.com/python/cpython/issues/126366]: Fix crash when using yield from on an object that raises an exception in its __iter__.

gh-126209 [https://github.com/python/cpython/issues/126209]: Fix an issue with skip_file_prefixes parameter which resulted in an inconsistent behaviour between the C and Python implementations of warnings.warn(). Patch by Daehee Kim.

gh-126312 [https://github.com/python/cpython/issues/126312]: Fix crash during garbage collection on an object frozen by gc.freeze() on the free-threaded build.

gh-103951 [https://github.com/python/cpython/issues/103951]: Relax optimization requirements to allow fast attribute access to module subclasses.

gh-126072 [https://github.com/python/cpython/issues/126072]: Following gh-126101 [https://github.com/python/cpython/issues/126101], for 코드 객체 like lambda, annotation and type alias, we no longer add None to its co_consts.

gh-126195 [https://github.com/python/cpython/issues/126195]: Improve JIT performance by 1.4% on macOS Apple Silicon by using platform-specific memory protection APIs. Patch by Diego Russo.

gh-126139 [https://github.com/python/cpython/issues/126139]: Provide better error location when attempting to use a future statement with an unknown future feature.

gh-126072 [https://github.com/python/cpython/issues/126072]: Add a new attribute in co_flags to indicate whether the first item in co_consts is the docstring. If a code object has no docstring, None will NOT be inserted.

gh-126076 [https://github.com/python/cpython/issues/126076]: Relocated objects such as tuple, bytes and str objects are properly tracked by tracemalloc and its associated hooks. Patch by Pablo Galindo.

gh-90370 [https://github.com/python/cpython/issues/90370]: Avoid temporary tuple creation for vararg in argument passing with Argument Clinic generated code (if arguments either vararg or positional-only).

gh-126018 [https://github.com/python/cpython/issues/126018]: Fix a crash in sys.audit() when passing a non-string as first argument and Python was compiled in debug mode.

gh-126012 [https://github.com/python/cpython/issues/126012]: The memoryview type now supports subscription, making it a generic type.

gh-125837 [https://github.com/python/cpython/issues/125837]: Adds LOAD_SMALL_INT and LOAD_CONST_IMMORTAL instructions. LOAD_SMALL_INT pushes a small integer equal to the oparg to the stack. LOAD_CONST_IMMORTAL does the same as LOAD_CONST but is more efficient for immortal objects. Removes RETURN_CONST instruction.

gh-125942 [https://github.com/python/cpython/issues/125942]: On Android, the errors setting of sys.stdout was changed from surrogateescape to backslashreplace.

gh-125859 [https://github.com/python/cpython/issues/125859]: Fix a crash in the free threading build when gc.get_objects() or gc.get_referrers() is called during an in-progress garbage collection.

gh-125868 [https://github.com/python/cpython/issues/125868]: It was possible in 3.14.0a1 only for attribute lookup to give the wrong value. This was due to an incorrect specialization in very specific circumstances. This is fixed in 3.14.0a2.

gh-125498 [https://github.com/python/cpython/issues/125498]: The JIT has been updated to leverage Clang 19’s new preserve_none attribute, which supports more platforms and is more useful than LLVM’s existing ghccc calling convention. This also removes the need to manually patch the calling convention in LLVM IR, simplifying the JIT compilation process.

gh-125703 [https://github.com/python/cpython/issues/125703]: Correctly honour tracemalloc hooks in specialized Py_DECREF paths. Patch by Pablo Galindo

gh-125593 [https://github.com/python/cpython/issues/125593]: Use color to highlight error locations in traceback from exception group

gh-125017 [https://github.com/python/cpython/issues/125017]: Fix crash on certain accesses to the __annotations__ of staticmethod and classmethod objects.

gh-125588 [https://github.com/python/cpython/issues/125588]: The Python PEG generator can now use f-strings in the grammar actions. Patch by Pablo Galindo

gh-125444 [https://github.com/python/cpython/issues/125444]: Fix illegal instruction for older Arm architectures. Patch by Diego Russo, testing by Ross Burton.

gh-118423 [https://github.com/python/cpython/issues/118423]: Add a new INSTRUCTION_SIZE macro to the cases generator which returns the current instruction size.

gh-125038 [https://github.com/python/cpython/issues/125038]: Fix crash when iterating over a generator expression after direct changes on gi_frame.f_locals. Patch by Mikhail Efimov.

gh-124855 [https://github.com/python/cpython/issues/124855]: Don’t allow the JIT and perf support to be active at the same time. Patch by Pablo Galindo

gh-123714 [https://github.com/python/cpython/issues/123714]: Update JIT compilation to use LLVM 19

gh-123930 [https://github.com/python/cpython/issues/123930]: Improve the error message when a script shadowing a module from the standard library causes ImportError to be raised during a “from” import. Similarly, improve the error message when a script shadowing a third party module attempts to “from” import an attribute from that third party module while still initialising.

gh-119793 [https://github.com/python/cpython/issues/119793]: The map() built-in now has an optional keyword-only strict flag like zip() to check that all the iterables are of equal length. Patch by Wannes Boeykens.

gh-118950 [https://github.com/python/cpython/issues/118950]: Fix bug where SSLProtocol.connection_lost wasn’t getting called when OSError was thrown on writing to socket.

gh-113570 [https://github.com/python/cpython/issues/113570]: Fixed a bug in reprlib.repr where it incorrectly called the repr method on shadowed Python built-in types.

C API

gh-126554 [https://github.com/python/cpython/issues/126554]: Fix error handling in ctypes.CDLL objects which could result in a crash in rare situations.

gh-126061 [https://github.com/python/cpython/issues/126061]: Add PyLong_IsPositive(), PyLong_IsNegative() and PyLong_IsZero() for checking if a PyLongObject is positive, negative, or zero, respectively.

gh-125608 [https://github.com/python/cpython/issues/125608]: Fix a bug where dictionary watchers (e.g., PyDict_Watch()) on an object’s attribute dictionary (__dict__) were not triggered when the object’s attributes were modified.

gh-123619 [https://github.com/python/cpython/issues/123619]: Added the PyUnstable_Object_EnableDeferredRefcount() function for enabling PEP 703 [https://peps.python.org/pep-0703/] deferred reference counting.

gh-121654 [https://github.com/python/cpython/issues/121654]: Add PyType_Freeze() function to make a type immutable. Patch by Victor Stinner.

gh-120026 [https://github.com/python/cpython/issues/120026]: The Py_HUGE_VAL macro is soft deprecated.

Build

gh-126691 [https://github.com/python/cpython/issues/126691]: Removed the --with-emscripten-target configure flag. We unified the node and browser options and the same build can now be used, independent of target runtime.

gh-123877 [https://github.com/python/cpython/issues/123877]: Use wasm32-wasip1 as the target triple for WASI instead of wasm32-wasi. The latter will eventually be reclaimed for WASI 1.0 while CPython currently only supports WASI preview1.

gh-126458 [https://github.com/python/cpython/issues/126458]: Disable SIMD support for HACL under WASI.

gh-89640 [https://github.com/python/cpython/issues/89640]: Hard-code float word ordering as little endian on WASM.

gh-126206 [https://github.com/python/cpython/issues/126206]: make clinic now runs Argument Clinic using the --force option, thus forcefully regenerating generated code.

gh-126187 [https://github.com/python/cpython/issues/126187]: Introduced Tools/wasm/emscripten.py to simplify doing Emscripten builds.

gh-124932 [https://github.com/python/cpython/issues/124932]: For cross builds, there is now support for having a different install prefix than the host_prefix used by getpath.py. This is set to / by default for Emscripten, on other platforms the default behavior is the same as before.

gh-125946 [https://github.com/python/cpython/issues/125946]: The minimum supported Android version is now 7.0 (API level 24).

gh-125940 [https://github.com/python/cpython/issues/125940]: The Android build now supports 16 KB page sizes [https://developer.android.com/guide/practices/page-sizes].

gh-89640 [https://github.com/python/cpython/issues/89640]: Improve detection of float word ordering on Linux when link-time optimizations are enabled.

gh-124928 [https://github.com/python/cpython/issues/124928]: Emscripten builds now require node >= 18.

gh-115382 [https://github.com/python/cpython/issues/115382]: Fix cross compile failures when the host and target SOABIs match.

Python 3.14.0 alpha 1

Release date: 2024-10-15

macOS

gh-124448 [https://github.com/python/cpython/issues/124448]: Update bundled Tcl/Tk in macOS installer to 8.6.15.

gh-123797 [https://github.com/python/cpython/issues/123797]: Check for runtime availability of ptsname_r function on macos.

gh-123418 [https://github.com/python/cpython/issues/123418]: Updated macOS installer build to use OpenSSL 3.0.15.

Windows

gh-124487 [https://github.com/python/cpython/issues/124487]: Increases Windows required OS and API level to Windows 10.

gh-124609 [https://github.com/python/cpython/issues/124609]: Fix _Py_ThreadId for Windows builds using MinGW. Patch by Tony Roberts.

gh-124448 [https://github.com/python/cpython/issues/124448]: Updated bundled Tcl/Tk to 8.6.15.

gh-124254 [https://github.com/python/cpython/issues/124254]: Ensures experimental free-threaded binaries remain installed when updating.

gh-123915 [https://github.com/python/cpython/issues/123915]: Ensure that Tools\msi\buildrelease.bat uses different directories for AMD64 and ARM64 builds.

gh-123418 [https://github.com/python/cpython/issues/123418]: Updated Windows build to use OpenSSL 3.0.15.

gh-123476 [https://github.com/python/cpython/issues/123476]: Add support for socket.TCP_QUICKACK on Windows platforms.

gh-122573 [https://github.com/python/cpython/issues/122573]: The Windows build of CPython now requires 3.10 or newer.

gh-100256 [https://github.com/python/cpython/issues/100256]: mimetypes no longer fails when it encounters an inaccessible registry key.

gh-119679 [https://github.com/python/cpython/issues/119679]: Ensures correct import libraries are included in Windows installs.

gh-119690 [https://github.com/python/cpython/issues/119690]: Adds Unicode support and fixes audit events for _winapi.CreateNamedPipe.

gh-111201 [https://github.com/python/cpython/issues/111201]: Add support for new pyrepl on Windows

gh-119070 [https://github.com/python/cpython/issues/119070]: Fixes py.exe handling of shebangs like /usr/bin/env python3.12, which were previously interpreted as python3.exe instead of python3.12.exe.

gh-117505 [https://github.com/python/cpython/issues/117505]: Fixes an issue with the Windows installer not running ensurepip in a fully isolated environment. This could cause unexpected interactions with the user site-packages.

gh-118209 [https://github.com/python/cpython/issues/118209]: Avoid crashing in mmap on Windows when the mapped memory is inaccessible due to file system errors or access violations.

gh-79846 [https://github.com/python/cpython/issues/79846]: Makes ssl.create_default_context() ignore invalid certificates in the Windows certificate store

Tools/Demos

gh-123418 [https://github.com/python/cpython/issues/123418]: Update GitHub CI workflows to use OpenSSL 3.0.15 and multissltests to use 3.0.15, 3.1.7, and 3.2.3.

Tests

gh-125041 [https://github.com/python/cpython/issues/125041]: Re-enable skipped tests for zlib on the s390x architecture: only skip checks of the compressed bytes, which can be different between zlib’s software implementation and the hardware-accelerated implementation.

gh-124378 [https://github.com/python/cpython/issues/124378]: Updated test_ttk to pass with Tcl/Tk 8.6.15.

gh-124213 [https://github.com/python/cpython/issues/124213]: Detect whether the test suite is running inside a systemd-nspawn container with --suppress-sync=true option, and skip the test_os and test_mmap tests that are failing in this scenario.

gh-124190 [https://github.com/python/cpython/issues/124190]: Add capability to ignore entire files or directories in check warning CI tool

gh-121921 [https://github.com/python/cpython/issues/121921]: Update Lib/test/crashers/bogus_code_obj.py so that it crashes properly again.

gh-112301 [https://github.com/python/cpython/issues/112301]: Add tooling to check for changes in compiler warnings. Patch by Nate Ohlson.

gh-59022 [https://github.com/python/cpython/issues/59022]: Add tests for pkgutil.extend_path(). Patch by Andreas Stocker.

gh-99242 [https://github.com/python/cpython/issues/99242]: os.getloadavg() may throw OSError when running regression tests under certain conditions (e.g. chroot). This error is now caught and ignored, since reporting load average is optional.

gh-121084 [https://github.com/python/cpython/issues/121084]: Fix test_typing random leaks. Clear typing ABC caches when running tests for refleaks (-R option): call _abc_caches_clear() on typing abstract classes and their subclasses. Patch by Victor Stinner.

gh-121160 [https://github.com/python/cpython/issues/121160]: Add a test for readline.set_history_length(). Note that this test may fail on readline libraries.

gh-121200 [https://github.com/python/cpython/issues/121200]: Fix test_expanduser_pwd2() of test_posixpath. Call getpwnam() to get pw_dir, since it can be different than getpwall() pw_dir. Patch by Victor Stinner.

gh-121188 [https://github.com/python/cpython/issues/121188]: When creating the JUnit XML file, regrtest now escapes characters which are invalid in XML, such as the chr(27) control character used in ANSI escape sequences. Patch by Victor Stinner.

gh-120801 [https://github.com/python/cpython/issues/120801]: Cleaned up fixtures for importlib.metadata tests and consolidated behavior with ‘test.support.os_helper’.

gh-119727 [https://github.com/python/cpython/issues/119727]: Add --single-process command line option to Python test runner (regrtest). Patch by Victor Stinner.

gh-119273 [https://github.com/python/cpython/issues/119273]: Python test runner no longer runs tests using TTY (ex: test_ioctl) in a process group (using setsid()). Previously, tests using TTY were skipped. Patch by Victor Stinner.

gh-119050 [https://github.com/python/cpython/issues/119050]: regrtest test runner: Add XML support to the refleak checker (-R option). Patch by Victor Stinner.

gh-101525 [https://github.com/python/cpython/issues/101525]: Skip test_gdb if the binary is relocated by BOLT. Patch by Donghee Na.

gh-107562 [https://github.com/python/cpython/issues/107562]: Test certificates have been updated to expire far in the future. This allows testing Y2038 with system time set to after that, so that actual Y2038 issues can be exposed, and not masked by expired certificate errors.

Security

gh-125140 [https://github.com/python/cpython/issues/125140]: Remove the current directory from sys.path when using PyREPL.

gh-123678 [https://github.com/python/cpython/issues/123678]: Upgrade libexpat to 2.6.3

gh-112301 [https://github.com/python/cpython/issues/112301]: Enable compiler options that warn of potential security vulnerabilities.

gh-122792 [https://github.com/python/cpython/issues/122792]: Changed IPv4-mapped ipaddress.IPv6Address to consistently use the mapped IPv4 address value for deciding properties. Properties which have their behavior fixed are is_multicast, is_reserved, is_link_local, is_global, and is_unspecified.

gh-112301 [https://github.com/python/cpython/issues/112301]: Add ability to ignore warnings per file with warning count in warning checking tooling. Patch by Nate Ohlson.

gh-112301 [https://github.com/python/cpython/issues/112301]: Add macOS warning tracking to warning check tooling. Patch by Nate Ohlson.

gh-122133 [https://github.com/python/cpython/issues/122133]: Authenticate the socket connection for the socket.socketpair() fallback on platforms where AF_UNIX is not available like Windows.

Patch by Gregory P. Smith <greg@krypto.org> and Seth Larson <seth@python.org>. Reported by Ellie <el@horse64.org>

gh-121957 [https://github.com/python/cpython/issues/121957]: Fixed missing audit events around interactive use of Python, now also properly firing for python -i, as well as for python -m asyncio. The events in question are cpython.run_stdin and cpython.run_startup.

gh-112301 [https://github.com/python/cpython/issues/112301]: Enable runtime protections for glibc to abort execution when unsafe behavior is encountered, for all platforms except Windows.

gh-121285 [https://github.com/python/cpython/issues/121285]: Remove backtracking from tarfile header parsing for hdrcharset, PAX, and GNU sparse headers.

gh-112301 [https://github.com/python/cpython/issues/112301]: Add default compiler options to improve security. Enable -Wimplicit-fallthrough, -fstack-protector-strong, -Wtrampolines.

gh-118773 [https://github.com/python/cpython/issues/118773]: Fixes creation of ACLs in os.mkdir() on Windows to work correctly on non-English machines.

gh-118486 [https://github.com/python/cpython/issues/118486]: os.mkdir() on Windows now accepts mode of 0o700 to restrict the new directory to the current user. This fixes CVE 2024-4030 [https://www.cve.org/CVERecord?id=CVE-2024-4030] affecting tempfile.mkdtemp() in scenarios where the base temporary directory is more permissive than the default.

Library

gh-125422 [https://github.com/python/cpython/issues/125422]: Fixed the bug where pdb and bdb can step into the bottom caller frame.

gh-100141 [https://github.com/python/cpython/issues/100141]: Fixed the bug where pdb will be stuck in an infinite loop when debugging an empty file.

gh-53203 [https://github.com/python/cpython/issues/53203]: Fix time.strptime() for %c, %x and %X formats in many locales that use non-ASCII digits, like Persian, Burmese, Odia and Shan.

gh-125206 [https://github.com/python/cpython/issues/125206]: Workaround for old libffi versions is added. Module ctypes supports double complex only with libffi >= 3.3.0. Patch by Mikhail Efimov.

gh-89967 [https://github.com/python/cpython/issues/89967]: Make WeakKeyDictionary and WeakValueDictionary safe against concurrent mutations from other threads. Patch by Kumar Aditya.

gh-125260 [https://github.com/python/cpython/issues/125260]: The gzip.compress() mtime parameter now defaults to 0 for reproducible output. Patch by Bernhard M. Wiedemann and Adam Turner.

gh-125243 [https://github.com/python/cpython/issues/125243]: Fix data race when creating zoneinfo.ZoneInfo objects in the free threading build.

gh-125254 [https://github.com/python/cpython/issues/125254]: Fix a bug where ArgumentError includes the incorrect ambiguous option in argparse.

gh-125235 [https://github.com/python/cpython/issues/125235]: Keep tkinter TCL paths in venv pointing to base installation on Windows.

gh-61011 [https://github.com/python/cpython/issues/61011]: Fix inheritance of nested mutually exclusive groups from parent parser in argparse.ArgumentParser. Previously, all nested mutually exclusive groups lost their connection to the group containing them and were displayed as belonging directly to the parser.

gh-125118 [https://github.com/python/cpython/issues/125118]: Don’t copy arbitrary values to _Bool in the struct module.

gh-125069 [https://github.com/python/cpython/issues/125069]: Fix an issue where providing a pathlib.PurePath object as an initializer argument to a second PurePath object with a different parser resulted in arguments to the former object’s initializer being joined by the latter object’s parser.

gh-125096 [https://github.com/python/cpython/issues/125096]: If the PYTHON_BASIC_REPL environment variable is set, the site module no longer imports the _pyrepl module. Moreover, the site module now respects -E and -I command line options: ignore PYTHON_BASIC_REPL in this case. Patch by Victor Stinner.

gh-124969 [https://github.com/python/cpython/issues/124969]: Fix locale.nl_langinfo(locale.ALT_DIGITS). Now it returns a tuple of up to 100 strings (an empty tuple on most locales). Previously it returned the first item of that tuple or an empty string.

gh-124960 [https://github.com/python/cpython/issues/124960]: Fix support for the barry_as_FLUFL future flag in the new REPL.

gh-69998 [https://github.com/python/cpython/issues/69998]: Fix locale.nl_langinfo() in case when different categories have different locales. The function now sets temporarily the LC_CTYPE locale in some cases. This temporary change affects other threads.

gh-124958 [https://github.com/python/cpython/issues/124958]: Fix refcycles in exceptions raised from asyncio.TaskGroup and the python implementation of asyncio.Future

gh-53203 [https://github.com/python/cpython/issues/53203]: Fix time.strptime() for %c and %x formats in many locales: Arabic, Bislama, Breton, Bodo, Kashubian, Chuvash, Estonian, French, Irish, Ge’ez, Gurajati, Manx Gaelic, Hebrew, Hindi, Chhattisgarhi, Haitian Kreyol, Japanese, Kannada, Korean, Marathi, Malay, Norwegian, Nynorsk, Punjabi, Rajasthani, Tok Pisin, Yoruba, Yue Chinese, Yau/Nungon and Chinese.

gh-123961 [https://github.com/python/cpython/issues/123961]: Convert curses to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]), thereby fixing reference leaks at interpreter shutdown. Patch by Bénédikt Tran.

gh-124944 [https://github.com/python/cpython/issues/124944]: Add SO_ORIGINAL_DST to the socket module.

gh-117151 [https://github.com/python/cpython/issues/117151]: The default buffer size used by shutil.copyfileobj() has been increased from 64k to 256k on non-Windows platforms. It was already larger on Windows.

gh-90102 [https://github.com/python/cpython/issues/90102]: Skip the isatty system call during open() when the file is known to not be a character device. This provides a slight performance improvement when reading whole files.

gh-124917 [https://github.com/python/cpython/issues/124917]: Allow calling os.path.exists() and os.path.lexists() with keyword arguments on Windows. Fixes a regression in 3.13.0.

gh-65865 [https://github.com/python/cpython/issues/65865]: argparse now raises early error for invalid help arguments to add_argument(), add_subparsers() and add_parser().

gh-124653 [https://github.com/python/cpython/issues/124653]: Fix detection of the minimal Queue API needed by the logging module. Patch by Bénédikt Tran.

gh-91818 [https://github.com/python/cpython/issues/91818]: The CLI of many modules (ast, ensurepip, json, pdb, sqlite3, tokenize, venv) now uses the actual executable name instead of simply “python” to display in the usage message.

gh-124858 [https://github.com/python/cpython/issues/124858]: Fix reference cycles left in tracebacks in asyncio.open_connection() when used with happy_eyeballs_delay

gh-124390 [https://github.com/python/cpython/issues/124390]: Fixed AssertionError when using asyncio.staggered.staggered_race() with asyncio.eager_task_factory.

gh-85935 [https://github.com/python/cpython/issues/85935]: argparse.ArgumentParser.add_argument() now raises an exception if an action that does not consume arguments (like ‘store_const’ or ‘store_true’) or explicit nargs=0 are specified for positional arguments.

gh-124835 [https://github.com/python/cpython/issues/124835]: Make tomllib.loads() raise TypeError not AttributeError on bad input types that do not have the replace attribute. Improve error message when bytes is received.

gh-124693 [https://github.com/python/cpython/issues/124693]: Fix a bug where argparse doesn’t recognize negative complex numbers or negative numbers using scientific notation.

gh-124787 [https://github.com/python/cpython/issues/124787]: Fix typing.TypeAliasType with incorrect type_params argument. Now it raises a TypeError when a type parameter without a default follows one with a default, and when an entry in the type_params tuple is not a type parameter object.

gh-66436 [https://github.com/python/cpython/issues/66436]: Improved prog default value for argparse.ArgumentParser. It will now include the name of the Python executable along with the module or package name, or the path to a directory, ZIP file, or directory within a ZIP file if the code was run that way.

gh-116850 [https://github.com/python/cpython/issues/116850]: Fix argparse for namespaces with not directly writable dict (e.g. classes).

gh-101552 [https://github.com/python/cpython/issues/101552]: Add an annoation_format parameter to inspect.signature(). Add an quote_annotation_strings parameter to inspect.Signature.format(). Use the new functionality to improve the display of annotations in signatures in pydoc. Patch by Jelle Zijlstra.

gh-58573 [https://github.com/python/cpython/issues/58573]: Fix conflicts between abbreviated long options in the parent parser and subparsers in argparse.

gh-124594 [https://github.com/python/cpython/issues/124594]: All asyncio REPL prompts run in the same context. Contributed by Bartosz Sławecki.

gh-61181 [https://github.com/python/cpython/issues/61181]: Fix support of choices with string value in argparse. Substrings of the specified string no longer considered valid values.

gh-116750 [https://github.com/python/cpython/issues/116750]: Provide sys.monitoring.clear_tool_id() to unregister all events and callbacks set by the tool.

gh-124552 [https://github.com/python/cpython/issues/124552]: Improve the accuracy of bdb’s check for the possibility of breakpoint in a frame. This makes it possible to disable unnecessary events in functions.

gh-124538 [https://github.com/python/cpython/issues/124538]: Fixed crash when using gc.get_referents() on a capsule object.

gh-80259 [https://github.com/python/cpython/issues/80259]: Fix argparse support of positional arguments with nargs='?', default=argparse.SUPPRESS and specified type.

gh-120378 [https://github.com/python/cpython/issues/120378]: Fix a crash related to an integer overflow in curses.resizeterm() and curses.resize_term().

gh-124498 [https://github.com/python/cpython/issues/124498]: Fix typing.TypeAliasType not to be generic, when type_params is an empty tuple.

gh-53834 [https://github.com/python/cpython/issues/53834]: Fix support of arguments with choices in argparse. Positional arguments with nargs equal to '?' or '*' no longer check default against choices. Optional arguments with nargs equal to '?' no longer check const against choices.

gh-123884 [https://github.com/python/cpython/issues/123884]: Fixed bug in itertools.tee() handling of other tee inputs (a tee in a tee). The output now has the promised n independent new iterators. Formerly, the first iterator was identical (not independent) to the input iterator. This would sometimes give surprising results.

gh-123017 [https://github.com/python/cpython/issues/123017]: Due to unreliable results on some devices, time.strftime() no longer accepts negative years on Android.

gh-123014 [https://github.com/python/cpython/issues/123014]: os.pidfd_open() and signal.pidfd_send_signal() are now unavailable when building against Android API levels older than 31, since the underlying system calls may cause a crash.

gh-124176 [https://github.com/python/cpython/issues/124176]: Add support for dataclasses.dataclass() in unittest.mock.create_autospec(). Now create_autospec will check for potential dataclasses and use dataclasses.fields() function to retrieve the spec information.

gh-124345 [https://github.com/python/cpython/issues/124345]: argparse vim supports abbreviated single-dash long options separated by = from its value.

gh-124400 [https://github.com/python/cpython/issues/124400]: Fixed a pdb bug where until has no effect when it appears in a commands sequence. Also avoid printing the frame information at a breakpoint that has a command list containing a command that resumes execution.

gh-90562 [https://github.com/python/cpython/issues/90562]: Modify dataclasses to support zero-argument super() when slots=True is specified. This works by modifying all references to __class__ to point to the newly created class.

gh-104860 [https://github.com/python/cpython/issues/104860]: Fix disallowing abbreviation of single-dash long options in argparse with allow_abbrev=False.

gh-63143 [https://github.com/python/cpython/issues/63143]: Fix parsing mutually exclusive arguments in argparse. Arguments with the value identical to the default value (e.g. booleans, small integers, empty or 1-character strings) are no longer considered “not present”.

gh-72795 [https://github.com/python/cpython/issues/72795]: Positional arguments with nargs equal to '*' or argparse.REMAINDER are no longer required. This allows to use positional argument with nargs='*' and without default in mutually exclusive group and improves error message about required arguments.

gh-59317 [https://github.com/python/cpython/issues/59317]: Fix parsing positional argument with nargs equal to '?' or '*' if it is preceded by an option and another positional argument.

gh-100980 [https://github.com/python/cpython/issues/100980]: The _fields_ attribute of ctypes.Structure and Union is no longer set if the setattr operation raises an error.

gh-53780 [https://github.com/python/cpython/issues/53780]: argparse now ignores the first "--" (double dash) between an option and command.

gh-124217 [https://github.com/python/cpython/issues/124217]: Add RFC 9637 reserved IPv6 block 3fff::/20 in ipaddress module.

gh-111513 [https://github.com/python/cpython/issues/111513]: Improve the error message that may be raised by datetime.date.fromtimestamp().

gh-124248 [https://github.com/python/cpython/issues/124248]: Fixed potential crash when using struct to process zero-width ‘Pascal string’ fields (0p).

gh-81691 [https://github.com/python/cpython/issues/81691]: Fix handling of multiple "--" (double dashes) in argparse. Only the first one has now been removed, all subsequent ones are now taken literally.

gh-87041 [https://github.com/python/cpython/issues/87041]: Fix a bug in argparse where lengthy subparser argument help is incorrectly indented.

gh-84559 [https://github.com/python/cpython/issues/84559]: The default multiprocessing start method on Linux and other POSIX systems has been changed away from often unsafe "fork" to "forkserver" (when the platform supports sending file handles over pipes as most do) or "spawn". Mac and Windows are unchanged as they already default to "spawn".

gh-124212 [https://github.com/python/cpython/issues/124212]: Fix invalid variable in venv handling of failed symlink on Windows

gh-124171 [https://github.com/python/cpython/issues/124171]: Add workaround for broken fmod() implementations on Windows, that loose zero sign (e.g. fmod(-10, 1) returns 0.0). Patch by Sergey B Kirpichev.

gh-123978 [https://github.com/python/cpython/issues/123978]: Remove broken time.thread_time() and time.thread_time_ns() on NetBSD.

gh-123934 [https://github.com/python/cpython/issues/123934]: Fix unittest.mock.MagicMock resetting magic methods return values after .reset_mock(return_value=True) was called.

gh-124016 [https://github.com/python/cpython/issues/124016]: Update unicodedata database to Unicode 16.0.0.

gh-123968 [https://github.com/python/cpython/issues/123968]: Fix the command-line interface for the random module to select floats between 0 and N, not 1 and N.

gh-123945 [https://github.com/python/cpython/issues/123945]: Fix a bug where argparse doesn’t recognize negative numbers with underscores

gh-123935 [https://github.com/python/cpython/issues/123935]: Fix parent slots detection for dataclasses that inherit from classes with __dictoffset__.

gh-123892 [https://github.com/python/cpython/issues/123892]: Add "_wmi" to sys.stdlib_module_names. Patch by Victor Stinner.

gh-84808 [https://github.com/python/cpython/issues/84808]: Fix error handling in socket method connect_ex() on platforms where errno can be negative.

gh-123756 [https://github.com/python/cpython/issues/123756]: Added a new argument mode to pdb.Pdb. Only allow pdb from command line to use restart command.

gh-122765 [https://github.com/python/cpython/issues/122765]: Fix unbalanced quote errors occurring when activate.csh in venv was sourced with a custom prompt containing unpaired quotes or newlines.

gh-123657 [https://github.com/python/cpython/issues/123657]: Fix crash and memory leak in decimal.getcontext(). It crashed when using a thread-local context by --with-decimal-contextvar=no.

gh-123339 [https://github.com/python/cpython/issues/123339]: Fix inspect.getsource() for classes in collections.abc and decimal (for pure Python implementation) modules. inspect.getcomments() now raises OSError instead of IndexError if the __firstlineno__ value for a class is out of bound.

gh-123374 [https://github.com/python/cpython/issues/123374]: Remove check for redefined memo entry in pickletools.dis().

gh-123504 [https://github.com/python/cpython/issues/123504]: Fixed reference leak in the finalization of tkinter.

gh-123430 [https://github.com/python/cpython/issues/123430]: Pages generated by the http.server module allow the browser to apply its default dark mode.

gh-123446 [https://github.com/python/cpython/issues/123446]: Fix empty function name in TypeError when csv.reader(), csv.writer(), or csv.register_dialect() are used without the required args.

gh-123448 [https://github.com/python/cpython/issues/123448]: Fixed memory leak of typing.NoDefault by moving it to the static types array.

gh-123409 [https://github.com/python/cpython/issues/123409]: Fix ipaddress.IPv6Address.reverse_pointer output according to RFC 3596, §2.5 [https://datatracker.ietf.org/doc/html/rfc3596.html#section-2.5]. Patch by Bénédikt Tran.

gh-123089 [https://github.com/python/cpython/issues/123089]: Make weakref.WeakSet safe against concurrent mutations while it is being iterated. Patch by Kumar Aditya.

gh-123363 [https://github.com/python/cpython/issues/123363]: Show string value of CONTAINS_OP oparg in dis output. Patch by Alexandr153.

gh-123341 [https://github.com/python/cpython/issues/123341]: Add __class_getitem__() to tkinter.Event for type subscript support at runtime. Patch by Adonis Rakateli.

gh-123340 [https://github.com/python/cpython/issues/123340]: Show string value of IS_OP oparg in dis output.

gh-119518 [https://github.com/python/cpython/issues/119518]: Speed up normalization of pathlib.PurePath and Path objects by not interning string parts.

gh-123270 [https://github.com/python/cpython/issues/123270]: Applied a more surgical fix for malformed payloads in zipfile.Path causing infinite loops (gh-122905 [https://github.com/python/cpython/issues/122905]) without breaking contents using legitimate characters.

gh-73991 [https://github.com/python/cpython/issues/73991]: Add pathlib.Path.copy_into() and move_into(), which copy and move files and directories into existing directories.

gh-123228 [https://github.com/python/cpython/issues/123228]: Fix return type for _pyrepl.readline._ReadlineWrapper.get_line_buffer() to be str(). Patch by Sergey B Kirpichev.

gh-123240 [https://github.com/python/cpython/issues/123240]: Raise audit events for the input() in the new REPL.

gh-76960 [https://github.com/python/cpython/issues/76960]: Fix urllib.parse.urljoin() and urllib.parse.urldefrag() for URIs containing empty components. For example, urljoin() with relative reference “?” now sets empty query and removes fragment. Preserve empty components (authority, params, query, fragment) in urljoin(). Preserve empty components (authority, params, query) in urldefrag().

gh-116810 [https://github.com/python/cpython/issues/116810]: Resolve a memory leak introduced in CPython 3.10’s ssl when the ssl.SSLSocket.session property was accessed. Speeds up read and write access to said property by no longer unnecessarily cloning session objects via serialization.

gh-123243 [https://github.com/python/cpython/issues/123243]: Fix memory leak in _decimal.

gh-122546 [https://github.com/python/cpython/issues/122546]: Consistently use same file name for different exceptions in the new repl. Patch by Sergey B Kirpichev.

gh-123213 [https://github.com/python/cpython/issues/123213]: xml.etree.ElementTree.Element.extend() and Element assignment no longer hide the internal exception if an erroneous generator is passed. Patch by Bar Harel.

gh-85110 [https://github.com/python/cpython/issues/85110]: Preserve relative path in URL without netloc in urllib.parse.urlunsplit() and urllib.parse.urlunparse().

gh-123165 [https://github.com/python/cpython/issues/123165]: Add support for rendering Positions in dis.

gh-122909 [https://github.com/python/cpython/issues/122909]: In urllib.request when URLError is raised opening an ftp URL, the exception argument is now consistently a string. Earlier versions passed either a string or an ftplib exception instance as the argument to URLError.

gh-123084 [https://github.com/python/cpython/issues/123084]: Deprecate shutil.ExecError, which hasn’t been raised by any shutil function since Python 3.4. It’s now an alias for RuntimeError.

gh-123085 [https://github.com/python/cpython/issues/123085]: In a bare call to importlib.resources.files(), ensure the caller’s frame is properly detected when importlib.resources is itself available as a compiled module only (no source).

gh-123067 [https://github.com/python/cpython/issues/123067]: Fix quadratic complexity in parsing "-quoted cookie values with backslashes by http.cookies.

gh-123049 [https://github.com/python/cpython/issues/123049]: Add support for UNNAMED_SECTION in configparser.ConfigParser.add_section().

gh-121735 [https://github.com/python/cpython/issues/121735]: When working with zip archives, importlib.resources now properly honors module-adjacent references (e.g. files(pkg.mod) and not just files(pkg)).

gh-122981 [https://github.com/python/cpython/issues/122981]: Fix inspect.getsource() for generated classes with Python base classes (e.g. enums).

gh-122903 [https://github.com/python/cpython/issues/122903]: zipfile.Path.glob now correctly matches directories instead of silently omitting them.

gh-122905 [https://github.com/python/cpython/issues/122905]: zipfile.Path objects now sanitize names from the zipfile.

gh-122873 [https://github.com/python/cpython/issues/122873]: Enable json module to work as a script using the -m switch: python -m json. See the JSON command-line interface documentation. Patch by Trey Hunner.

gh-122858 [https://github.com/python/cpython/issues/122858]: Deprecate asyncio.iscoroutinefunction() in favor of inspect.iscoroutinefunction().

gh-116263 [https://github.com/python/cpython/issues/116263]: logging.handlers.RotatingFileHandler no longer rolls over empty log files.

gh-105376 [https://github.com/python/cpython/issues/105376]: Restore the deprecated logging warn() method. It was removed in Python 3.13 alpha 1. Keep the deprecated warn() method in Python 3.13. Patch by Victor Stinner.

gh-122311 [https://github.com/python/cpython/issues/122311]: Improve errors in the pickle module. PicklingError is now raised more often instead of UnicodeEncodeError, ValueError and AttributeError, and the original exception is chained to it. Improve and unify error messages in Python and C implementations.

gh-122744 [https://github.com/python/cpython/issues/122744]: Bump the version of pip bundled in ensurepip to version 24.2.

gh-118761 [https://github.com/python/cpython/issues/118761]: Improve import time of pprint by around seven times. Patch by Hugo van Kemenade.

gh-118974 [https://github.com/python/cpython/issues/118974]: Add decorator parameter to dataclasses.make_dataclass() to customize the functional creation of dataclasses.

gh-118814 [https://github.com/python/cpython/issues/118814]: Fix the typing.TypeVar constructor when name is passed by keyword.

gh-122637 [https://github.com/python/cpython/issues/122637]: Adjust cmath.tanh(nanj) and cmath.tanh(infj) for recent C standards.

gh-122478 [https://github.com/python/cpython/issues/122478]: Remove internal frames from tracebacks shown in code.InteractiveInterpreter with non-default sys.excepthook(). Save correct tracebacks in sys.last_traceback and update __traceback__ attribute of sys.last_value and sys.last_exc.

gh-116622 [https://github.com/python/cpython/issues/116622]: On Android, the FICLONE and FICLONERANGE constants are no longer exposed by fcntl, as these ioctls are blocked by SELinux.

gh-82378 [https://github.com/python/cpython/issues/82378]: Make sure that the new REPL interprets sys.tracebacklimit in the same way that the classic REPL did.

gh-122334 [https://github.com/python/cpython/issues/122334]: Fix crash when importing ssl after the main interpreter restarts.

gh-122459 [https://github.com/python/cpython/issues/122459]: Optimize pickling by name objects without the __module__ attribute.

gh-87320 [https://github.com/python/cpython/issues/87320]: In code.InteractiveInterpreter, handle exceptions caused by calling a non-default sys.excepthook(). Before, the exception bubbled up to the caller, ending the REPL.

gh-122272 [https://github.com/python/cpython/issues/122272]: On some platforms such as Linux, year with century was not 0-padded when formatted by strftime() with C99-specific specifiers '%C' or '%F'. The 0-padding behavior is now guaranteed when the format specifiers '%C' and '%F' are supported by the C library. Patch by Ben Hsing

gh-122400 [https://github.com/python/cpython/issues/122400]: Handle ValueErrors raised by os.stat() in filecmp.dircmp and filecmp.cmpfiles(). Patch by Bénédikt Tran.

gh-122311 [https://github.com/python/cpython/issues/122311]: Fix some error messages in pickle.

gh-121650 [https://github.com/python/cpython/issues/121650]: email headers with embedded newlines are now quoted on output. The generator will now refuse to serialize (write) headers that are unsafely folded or delimited; see verify_generated_headers. (Contributed by Bas Bloemsaat and Petr Viktorin in gh-121650 [https://github.com/python/cpython/issues/121650].)

gh-122332 [https://github.com/python/cpython/issues/122332]: Fixed segfault with asyncio.Task.get_coro() when using an eager task factory.

gh-105733 [https://github.com/python/cpython/issues/105733]: ctypes.ARRAY() is now soft deprecated: it no longer emits deprecation warnings and is not scheduled for removal.

gh-122213 [https://github.com/python/cpython/issues/122213]: Add notes for pickle serialization errors that allow to identify the source of the error.

gh-119180 [https://github.com/python/cpython/issues/119180]: As part of PEP 749 [https://peps.python.org/pep-0749/], add the following attributes for customizing evaluation of annotation scopes:

evaluate_value on typing.TypeAliasType

evaluate_bound, evaluate_constraints, and evaluate_default on typing.TypeVar

evaluate_default on typing.ParamSpec

evaluate_default on typing.TypeVarTuple

gh-119180 [https://github.com/python/cpython/issues/119180]: Fix handling of classes with custom metaclasses in annotationlib.get_annotations.

gh-122170 [https://github.com/python/cpython/issues/122170]: Handle ValueErrors raised by os.stat() in linecache. Patch by Bénédikt Tran.

gh-122163 [https://github.com/python/cpython/issues/122163]: Add notes for JSON serialization errors that allow to identify the source of the error.

gh-122129 [https://github.com/python/cpython/issues/122129]: Improve support of method descriptors and wrappers in the help title.

gh-122145 [https://github.com/python/cpython/issues/122145]: Fix an issue when reporting tracebacks corresponding to Python code emitting an empty AST body. Patch by Nikita Sobolev and Bénédikt Tran.

gh-121723 [https://github.com/python/cpython/issues/121723]: Make logging.config.dictConfig() accept any object implementing the Queue public API. See the queue configuration section for details. Patch by Bénédikt Tran.

gh-82951 [https://github.com/python/cpython/issues/82951]: Serializing objects with complex __qualname__ (such as unbound methods and nested classes) by name no longer involves serializing parent objects by value in pickle protocols < 4.

gh-120754 [https://github.com/python/cpython/issues/120754]: Pathlib.read_bytes no longer opens the file in Python’s buffered I/O mode. This reduces overheads as the code reads a file in whole leading to a modest speedup.

gh-113785 [https://github.com/python/cpython/issues/113785]: csv now correctly parses numeric fields (when used with csv.QUOTE_NONNUMERIC or csv.QUOTE_STRINGS) which start with an escape character.

gh-122088 [https://github.com/python/cpython/issues/122088]: @warnings.deprecated now copies the coroutine status of functions and methods so that inspect.iscoroutinefunction() returns the correct result.

gh-122081 [https://github.com/python/cpython/issues/122081]: Fix a crash in the decimal.IEEEContext() optional function available via the EXTRA_FUNCTIONALITY configuration flag.

gh-73991 [https://github.com/python/cpython/issues/73991]: Add pathlib.Path.move(), which moves a file or directory tree.

gh-121268 [https://github.com/python/cpython/issues/121268]: Remove workarounds for non-IEEE 754 systems in cmath.

gh-119698 [https://github.com/python/cpython/issues/119698]: Due to the lack of interest for symtable.Class.get_methods(), the method is marked as deprecated and will be removed in Python 3.16. Patch by Bénédikt Tran.

gh-121889 [https://github.com/python/cpython/issues/121889]: Adjusts cmath.acosh(complex('0+nanj')) for recent C standards.

gh-121804 [https://github.com/python/cpython/issues/121804]: Correctly show error locations, when SyntaxError raised in new repl. Patch by Sergey B Kirpichev.

gh-121797 [https://github.com/python/cpython/issues/121797]: Add alternative Fraction constructor Fraction.from_number().

gh-121798 [https://github.com/python/cpython/issues/121798]: Add alternative Decimal constructor Decimal.from_number().

gh-120930 [https://github.com/python/cpython/issues/120930]: Fixed a bug introduced by gh-92081 [https://github.com/python/cpython/issues/92081] that added an incorrect extra blank to encoded words occurring in wrapped headers.

gh-57141 [https://github.com/python/cpython/issues/57141]: The shallow argument to filecmp.dircmp (new in Python 3.13) is now keyword-only.

gh-121245 [https://github.com/python/cpython/issues/121245]: Simplify handling of the history file in site.register_readline() helper. The CAN_USE_PYREPL variable now will be initialized, when imported. Patch by Sergey B Kirpichev.

gh-121249 [https://github.com/python/cpython/issues/121249]: Support the float complex and double complex C types in the struct module if the compiler has C11 complex arithmetic. Patch by Sergey B Kirpichev.

gh-121486 [https://github.com/python/cpython/issues/121486]: math functions isqrt(), log(), log2() and log10() now support integers larger than 2**2**32 on 32-bit platforms.

gh-121474 [https://github.com/python/cpython/issues/121474]: Fix missing sanity check for parties arg in threading.Barrier constructor. Patch by Clinton Christian (pygeek).

gh-121450 [https://github.com/python/cpython/issues/121450]: Hard-coded breakpoints (breakpoint() and pdb.set_trace()) now reuse the most recent Pdb instance that calls Pdb.set_trace(), instead of creating a new one each time. As a result, all the instance specific data like display and commands are preserved across Hard-coded breakpoints.

gh-119169 [https://github.com/python/cpython/issues/119169]: Slightly speed up os.walk() by simplifying exception handling.

gh-121423 [https://github.com/python/cpython/issues/121423]: Improve import time of socket by lazy importing modules and writing socket.errorTab as a constant.

gh-59110 [https://github.com/python/cpython/issues/59110]: zipimport supports now namespace packages when no directory entry exists.

gh-119004 [https://github.com/python/cpython/issues/119004]: Fix a crash in OrderedDict.__eq__ when operands are mutated during the check. Patch by Bénédikt Tran.

gh-121313 [https://github.com/python/cpython/issues/121313]: Limit the reading size in the multiprocessing.connection.Connection class to 64 KiB to prevent memory overallocation and unnecessary memory management system calls.

gh-121332 [https://github.com/python/cpython/issues/121332]: Fix constructor of ast nodes with custom _attributes. Previously, passing custom attributes would raise a DeprecationWarning. Passing arguments to the constructor that are not in _fields or _attributes remains deprecated. Patch by Jelle Zijlstra.

gh-121245 [https://github.com/python/cpython/issues/121245]: Fix a bug in the handling of the command history of the new REPL that caused the history file to be wiped at REPL exit.

gh-121210 [https://github.com/python/cpython/issues/121210]: Handle AST nodes with missing runtime fields or attributes in ast.compare(). Patch by Bénédikt Tran.

gh-121163 [https://github.com/python/cpython/issues/121163]: Add support for all as an valid action for warnings.simplefilter() and warnings.filterwarnings().

gh-121151 [https://github.com/python/cpython/issues/121151]: Fix wrapping of long usage text of arguments inside a mutually exclusive group in argparse.

gh-121141 [https://github.com/python/cpython/issues/121141]: Add support for copy.replace() to AST nodes. Patch by Bénédikt Tran.

gh-87744 [https://github.com/python/cpython/issues/87744]: Fix waitpid race while calling send_signal() in asyncio. Patch by Kumar Aditya.

gh-121027 [https://github.com/python/cpython/issues/121027]: Add a future warning in functools.partial.__get__(). In future Python versions functools.partial will be a method descriptor.

gh-121027 [https://github.com/python/cpython/issues/121027]: Make the functools.partial object a method descriptor.

gh-117784 [https://github.com/python/cpython/issues/117784]: CPython now detects whether its linked TLS library supports TLSv1.3 post-handshake authentication and disables that feature if support is lacking.

gh-121025 [https://github.com/python/cpython/issues/121025]: Improve the __repr__() of functools.partialmethod. Patch by Bénédikt Tran.

gh-121018 [https://github.com/python/cpython/issues/121018]: Fixed issues where argparse.ArgumentParser.parse_args() did not honor exit_on_error=False. Based on patch by Ben Hsing.

gh-119614 [https://github.com/python/cpython/issues/119614]: Fix truncation of strings with embedded null characters in some internal operations in tkinter.

gh-120910 [https://github.com/python/cpython/issues/120910]: When reading installed files from an egg, use relative_to(walk_up=True) to honor files installed outside of the installation root.

gh-61103 [https://github.com/python/cpython/issues/61103]: Support float complex, double complex and long double complex C types in ctypes as c_float_complex, c_double_complex and c_longdouble_complex if the compiler has C11 complex arithmetic. Patch by Sergey B Kirpichev.

gh-120888 [https://github.com/python/cpython/issues/120888]: Upgrade pip wheel bundled with ensurepip (pip 24.1.1)

gh-101830 [https://github.com/python/cpython/issues/101830]: Accessing the tkinter object’s string representation no longer converts the underlying Tcl object to a string on Windows.

gh-120678 [https://github.com/python/cpython/issues/120678]: Fix regression in the new REPL that meant that globals from files passed using the -i argument would not be included in the REPL’s global namespace. Patch by Alex Waygood.

gh-120811 [https://github.com/python/cpython/issues/120811]: Fix possible memory leak in contextvars.Context.run().

gh-120782 [https://github.com/python/cpython/issues/120782]: Fix wrong references of the datetime types after reloading the module.

gh-120713 [https://github.com/python/cpython/issues/120713]: datetime.datetime.strftime() now 0-pads years with less than four digits for the format specifiers %Y and %G on Linux. Patch by Ben Hsing

gh-120769 [https://github.com/python/cpython/issues/120769]: Make empty line in pdb repeats the last command even when the command is from cmdqueue.

gh-120780 [https://github.com/python/cpython/issues/120780]: Show string value of LOAD_SPECIAL oparg in dis output.

gh-41431 [https://github.com/python/cpython/issues/41431]: Add datetime.time.strptime() and datetime.date.strptime(). Contributed by Wannes Boeykens.

gh-120743 [https://github.com/python/cpython/issues/120743]: Soft deprecate os.popen() and os.spawn* functions. They should no longer be used to write new code. The subprocess module is recommended instead. Patch by Victor Stinner.

gh-120732 [https://github.com/python/cpython/issues/120732]: Fix name passing to unittest.mock.Mock object when using unittest.mock.create_autospec().

gh-111259 [https://github.com/python/cpython/issues/111259]: re now handles patterns like "[\s\S]" or "\s|\S" which match any character as effectively as a dot with the DOTALL modifier ("(?s:.)").

gh-120683 [https://github.com/python/cpython/issues/120683]: Fix an error in logging.LogRecord, when the integer part of the timestamp is rounded up, while the millisecond calculation truncates, causing the log timestamp to be wrong by up to 999 ms (affected roughly 1 in 8 million timestamps).

gh-118710 [https://github.com/python/cpython/issues/118710]: ipaddress.IPv4Address and ipaddress.IPv6Address attributes version and max_prefixlen are now available on the class.

gh-120633 [https://github.com/python/cpython/issues/120633]: Move scrollbar and remove tear-off menus in turtledemo.

gh-120606 [https://github.com/python/cpython/issues/120606]: Allow users to use EOF to exit commands definition in pdb

gh-120284 [https://github.com/python/cpython/issues/120284]: Allow asyncio.Runner.run() to accept awaitable objects instead of simply coroutines.

gh-120541 [https://github.com/python/cpython/issues/120541]: Improve the prompt in the “less” pager when help() is called with non-string argument.

gh-120495 [https://github.com/python/cpython/issues/120495]: Fix incorrect exception handling in Tab Nanny. Patch by Wulian233.

gh-120388 [https://github.com/python/cpython/issues/120388]: Improve a warning message when a test method in unittest returns something other than None. Now we show the returned object type and optional asyncio-related tip.

gh-120381 [https://github.com/python/cpython/issues/120381]: Correct inspect.ismethoddescriptor() to check also for the lack of __delete__(). Patch by Jan Kaliszewski.

gh-90425 [https://github.com/python/cpython/issues/90425]: The OS byte in gzip headers is now always set to 255 when using gzip.compress().

gh-120343 [https://github.com/python/cpython/issues/120343]: Fix column offset reporting for tokens that come after multiline f-strings in the tokenize module.

gh-119180 [https://github.com/python/cpython/issues/119180]: As part of implementing PEP 649 [https://peps.python.org/pep-0649/] and PEP 749 [https://peps.python.org/pep-0749/], add a new module annotationlib. Add support for unresolved forward references in annotations to dataclasses, typing.TypedDict, and typing.NamedTuple.

gh-119600 [https://github.com/python/cpython/issues/119600]: Fix unittest.mock.patch() to not read attributes of the target when new_callable is set. Patch by Robert Collins.

gh-120289 [https://github.com/python/cpython/issues/120289]: Fixed the use-after-free issue in cProfile by disallowing disable() and clear() in external timers.

gh-82017 [https://github.com/python/cpython/issues/82017]: Added support for converting any objects that have the as_integer_ratio() method to a Fraction.

gh-114053 [https://github.com/python/cpython/issues/114053]: Fix edge-case bug where typing.get_type_hints() would produce incorrect results if type parameters in a class scope were overridden by assignments in a class scope and from __future__ import annotations semantics were enabled. Patch by Alex Waygood.

gh-114053 [https://github.com/python/cpython/issues/114053]: Fix erroneous NameError when calling inspect.get_annotations() with eval_str=True` on a class that made use of PEP 695 [https://peps.python.org/pep-0695/] type parameters in a module that had from __future__ import annotations at the top of the file. Patch by Alex Waygood.

gh-120268 [https://github.com/python/cpython/issues/120268]: Prohibit passing None to pure-Python datetime.date.fromtimestamp() to achieve consistency with C-extension implementation.

gh-120244 [https://github.com/python/cpython/issues/120244]: Fix memory leak in re.sub() when the replacement string contains backreferences.

gh-120254 [https://github.com/python/cpython/issues/120254]: Added commands argument to pdb.set_trace() which allows users to send debugger commands from the source file.

gh-120211 [https://github.com/python/cpython/issues/120211]: Fix tkinter.ttk with Tcl/Tk 9.0.

gh-71587 [https://github.com/python/cpython/issues/71587]: Fix crash in C version of datetime.datetime.strptime() when called again on the restarted interpreter.

gh-117983 [https://github.com/python/cpython/issues/117983]: Defer the threading import in importlib.util until lazy loading is used.

gh-120157 [https://github.com/python/cpython/issues/120157]: Remove unused constant concurrent.futures._base._FUTURE_STATES in concurrent.futures. Patch by Clinton Christian (pygeek).

gh-120161 [https://github.com/python/cpython/issues/120161]: datetime no longer crashes in certain complex reference cycle situations.

gh-119698 [https://github.com/python/cpython/issues/119698]: Fix symtable.Class.get_methods() and document its behaviour. Patch by Bénédikt Tran.

gh-120121 [https://github.com/python/cpython/issues/120121]: Add concurrent.futures.InvalidStateError to module’s __all__.

gh-119933 [https://github.com/python/cpython/issues/119933]: Add the symtable.SymbolTableType enumeration to represent the possible outputs of the symtable.SymbolTable.get_type method. Patch by Bénédikt Tran.

gh-120029 [https://github.com/python/cpython/issues/120029]: Expose symtable.Symbol methods is_free_class(), is_comp_iter() and is_comp_cell(). Patch by Bénédikt Tran.

gh-120108 [https://github.com/python/cpython/issues/120108]: Fix calling copy.deepcopy() on ast trees that have been modified to have references to parent nodes. Patch by Jelle Zijlstra.

gh-120056 [https://github.com/python/cpython/issues/120056]: Add socket.IP_RECVERR and socket.IP_RECVTTL constants (both available since Linux 2.2). And socket.IP_RECVORIGDSTADDR constant (available since Linux 2.6.29).

gh-112672 [https://github.com/python/cpython/issues/112672]: Support building tkinter with Tcl 9.0.

gh-120057 [https://github.com/python/cpython/issues/120057]: Added the os.environ.refresh() method to update os.environ with changes to the environment made by os.putenv(), by os.unsetenv(), or made outside Python in the same process. Patch by Victor Stinner.

gh-120029 [https://github.com/python/cpython/issues/120029]: Expose symtable.Symbol.is_type_parameter() in the symtable module. Patch by Bénédikt Tran.

gh-119819 [https://github.com/python/cpython/issues/119819]: Fix regression to allow logging configuration with multiprocessing queue types.

gh-65454 [https://github.com/python/cpython/issues/65454]: unittest.mock.Mock.attach_mock() no longer triggers a call to a PropertyMock being attached.

gh-117142 [https://github.com/python/cpython/issues/117142]: The ctypes module may now be imported in all subinterpreters, including those that have their own GIL.

gh-118835 [https://github.com/python/cpython/issues/118835]: Fix _pyrepl crash when using custom prompt with ANSI escape codes.

gh-81936 [https://github.com/python/cpython/issues/81936]: help() and showtopic() methods now respect a configured output argument to pydoc.Helper and not use the pager in such cases. Patch by Enrico Tröger.

gh-117398 [https://github.com/python/cpython/issues/117398]: The _datetime module (C implementation for datetime) now supports being imported in multiple interpreters.

gh-119824 [https://github.com/python/cpython/issues/119824]: Print stack entry in pdb when and only when user input is needed.

gh-119838 [https://github.com/python/cpython/issues/119838]: In mixed arithmetic operations with Fraction and complex, the fraction is now converted to float instead of complex.

gh-119770 [https://github.com/python/cpython/issues/119770]: Make termios ioctl() constants positive. Patch by Victor Stinner.

gh-89727 [https://github.com/python/cpython/issues/89727]: Fix issue with shutil.rmtree() where a RecursionError is raised on deep directory trees.

gh-119577 [https://github.com/python/cpython/issues/119577]: The DeprecationWarning emitted when testing the truth value of an xml.etree.ElementTree.Element now describes unconditionally returning True in a future version rather than raising an exception in Python 3.14.

gh-89727 [https://github.com/python/cpython/issues/89727]: Partially fix issue with shutil.rmtree() where a RecursionError is raised on deep directory trees. A recursion error is no longer raised when rmtree.avoids_symlink_attacks is false.

gh-93963 [https://github.com/python/cpython/issues/93963]: Remove deprecated names from importlib.abc as found in importlib.resources.abc.

gh-119118 [https://github.com/python/cpython/issues/119118]: Fix performance regression in the tokenize module by caching the line token attribute and calculating the column offset more efficiently.

gh-89727 [https://github.com/python/cpython/issues/89727]: Fix issue with os.fwalk() where a RecursionError was raised on deep directory trees by adjusting the implementation to be iterative instead of recursive.

gh-119594 [https://github.com/python/cpython/issues/119594]: If one calls pow(fractions.Fraction, x, module) with modulo not None, the error message now says that the types are incompatible rather than saying pow only takes 2 arguments. Patch by Wim Jeantine-Glenn and Mark Dickinson.

gh-119588 [https://github.com/python/cpython/issues/119588]: zipfile.Path.is_symlink now assesses if the given path is a symlink.

gh-119562 [https://github.com/python/cpython/issues/119562]: Remove ast.Num, ast.Str, ast.Bytes, ast.NameConstant and ast.Ellipsis. They had all emitted deprecation warnings since Python 3.12. Patch by Alex Waygood.

gh-119555 [https://github.com/python/cpython/issues/119555]: Catch SyntaxError from compile() in the runsource() method of the InteractiveColoredConsole. Patch by Sergey B Kirpichev.

gh-118908 [https://github.com/python/cpython/issues/118908]: Limit exposed globals from internal imports and definitions on new REPL startup. Patch by Eugene Triguba and Pablo Galindo.

gh-117865 [https://github.com/python/cpython/issues/117865]: Improve the import time of the ast module by deferring the import of re. Patch by Jelle Zijlstra.

gh-119127 [https://github.com/python/cpython/issues/119127]: Positional arguments of functools.partial() objects now support placeholders via functools.Placeholder.

gh-113892 [https://github.com/python/cpython/issues/113892]: Now, the method sock_connect of asyncio.ProactorEventLoop raises a ValueError if given socket is not in non-blocking mode, as well as in other loop implementations.

gh-119506 [https://github.com/python/cpython/issues/119506]: Fix io.TextIOWrapper.write() method breaks internal buffer when the method is called again during flushing internal buffer.

gh-69214 [https://github.com/python/cpython/issues/69214]: Fix fcntl.ioctl() request parameter: use an unsigned long instead of an unsigned int for the request parameter of fcntl.ioctl() to support requests larger than UINT_MAX. Patch by Victor Stinner.

gh-119105 [https://github.com/python/cpython/issues/119105]: difflib’s DIffer.compare() (and so also ndiff) can no longer be provoked into cubic-time behavior, or into unbounded recursion, and should generally be faster in ordinary cases too. Results may change in some cases, although that should be rare. Correctness of diffs is not affected. Some similar lines far apart may be reported as deleting one and adding the other, where before they were displayed on adjacent output lines with markup showing the intraline differences.

gh-119443 [https://github.com/python/cpython/issues/119443]: The interactive REPL no longer runs with from __future__ import annotations enabled. Patch by Jelle Zijlstra.

gh-119461 [https://github.com/python/cpython/issues/119461]: Add socket.VMADDR_CID_LOCAL constant. Patch by Victor Stinner.

gh-117398 [https://github.com/python/cpython/issues/117398]: Objects in the datetime C-API are now all statically allocated, which means better memory safety, especially when the module is reloaded. This should be transparent to users.

gh-118894 [https://github.com/python/cpython/issues/118894]: asyncio REPL now has the same capabilities as PyREPL.

gh-118830 [https://github.com/python/cpython/issues/118830]: Bump pickle default protocol to 5.

gh-118911 [https://github.com/python/cpython/issues/118911]: In PyREPL, updated maybe-accept’s logic so that if the user hits Enter twice, they are able to terminate the block even if there’s trailing whitespace. Also, now when the user hits arrow up, the cursor is on the last functional line. This matches IPython’s behavior. Patch by Aya Elsayed.

gh-115225 [https://github.com/python/cpython/issues/115225]: Raise error on certain technically valid but pathological ISO 8601 strings passed to datetime.time.fromisoformat() that were previously parsed incorrectly.

gh-111201 [https://github.com/python/cpython/issues/111201]: Remove dependency to readline from the new Python REPL.

gh-119189 [https://github.com/python/cpython/issues/119189]: When using the ** operator or pow() with Fraction as the base and an exponent that is not rational, a float, or a complex, the fraction is no longer converted to a float.

gh-119174 [https://github.com/python/cpython/issues/119174]: Fix high DPI causes turtledemo(turtle-graphics examples) windows blurry Patch by Wulian233 and Terry Jan Reedy

gh-119121 [https://github.com/python/cpython/issues/119121]: Fix a NameError happening in asyncio.staggered.staggered_race. This function is now tested.

gh-119105 [https://github.com/python/cpython/issues/119105]: difflib.Differ is much faster for some cases of diffs where many pairs of lines are equally similar.

gh-119113 [https://github.com/python/cpython/issues/119113]: Fix issue where pathlib.PurePath.with_suffix() didn’t raise TypeError when given None as a suffix.

gh-118643 [https://github.com/python/cpython/issues/118643]: Fix an AttributeError in the email module when re-fold a long address list. Also fix more cases of incorrect encoding of the address separator in the address list.

gh-73991 [https://github.com/python/cpython/issues/73991]: Add pathlib.Path.copy(), which copies a file or directory to another.

gh-58933 [https://github.com/python/cpython/issues/58933]: Make pdb return to caller frame correctly when f_trace of the caller frame is not set

gh-82805 [https://github.com/python/cpython/issues/82805]: Support single-dot file extensions in pathlib.PurePath.suffix and related attributes and methods. For example, the suffixes of PurePath('foo.bar.') are now ['.bar', '.'] rather than []. This brings file extension splitting in line with os.path.splitext().

gh-118924 [https://github.com/python/cpython/issues/118924]: Remove version and version_info from sqlite3. Patch by Hugo van Kemenade.

gh-118928 [https://github.com/python/cpython/issues/118928]: Disallow using a sequence of parameters with named placeholders in sqlite3 queries. Patch by Erlend E. Aasland.

gh-118895 [https://github.com/python/cpython/issues/118895]: Setting attributes on typing.NoDefault now raises AttributeError instead of TypeError.

gh-118868 [https://github.com/python/cpython/issues/118868]: Fixed issue where kwargs were no longer passed to the logging handler QueueHandler

gh-118827 [https://github.com/python/cpython/issues/118827]: Remove deprecated Quoter class from urllib.parse. It had previously raised a DeprecationWarning since Python 3.11. Patch by Nikita Sobolev.

gh-118824 [https://github.com/python/cpython/issues/118824]: Remove deprecated pty.master_open() and pty.slave_open(). Use pty.openpty() instead. Patch by Nikita Sobolev.

gh-118851 [https://github.com/python/cpython/issues/118851]: ctx arguments to the constructors of ast node classes now default to ast.Load(). Patch by Jelle Zijlstra.

gh-101588 [https://github.com/python/cpython/issues/101588]: Remove copy, deepcopy, and pickle from itertools. These had previously raised a DeprecationWarning since Python 3.12.

gh-118805 [https://github.com/python/cpython/issues/118805]: Remove type, choices, and metavar parameters of argparse.BooleanOptionalAction. They were deprecated since Python 3.12.

gh-118803 [https://github.com/python/cpython/issues/118803]: typing.ByteString and collections.abc.ByteString are removed. They had previously raised a DeprecationWarning since Python 3.12.

gh-118798 [https://github.com/python/cpython/issues/118798]: The isdst parameter has been removed from email.utils.localtime(). Patch by Hugo van Kemenade.

gh-118760 [https://github.com/python/cpython/issues/118760]: Restore the default value of tkiter.wantobjects to 1.

gh-118760 [https://github.com/python/cpython/issues/118760]: Fix errors in calling Tkinter bindings on Windows.

gh-74033 [https://github.com/python/cpython/issues/74033]: Drop support for passing keyword arguments to pathlib.Path.

gh-101357 [https://github.com/python/cpython/issues/101357]: Suppress all OSError exceptions from pathlib.Path.exists() and is_*() methods, rather than a selection of more common errors. The new behaviour is consistent with os.path.exists(), os.path.isdir(), etc. Use pathlib.Path.stat() to retrieve the file status without suppressing exceptions.

gh-78707 [https://github.com/python/cpython/issues/78707]: Drop support for passing additional positional arguments to pathlib.PurePath.relative_to() and is_relative_to().

gh-118507 [https://github.com/python/cpython/issues/118507]: Fix os.path.isfile() on Windows for pipes. Speedup os.path.isjunction() and os.path.lexists() on Windows with a native implementation.

gh-118772 [https://github.com/python/cpython/issues/118772]: Allow typing.TypeVar instances without a default to follow instances without a default in some cases. Patch by Jelle Zijlstra.

gh-118714 [https://github.com/python/cpython/issues/118714]: Allow restart in post-mortem debugging of pdb. Removed restart message when the user quits pdb from post-mortem mode.

gh-118673 [https://github.com/python/cpython/issues/118673]: Removed executable bits and shebang from stdlib modules.

gh-110863 [https://github.com/python/cpython/issues/110863]: os.path.realpath() now suppresses any OSError from os.readlink() when strict mode is disabled (the default).

gh-118263 [https://github.com/python/cpython/issues/118263]: Speed up os.path.splitroot() & os.path.normpath() with a direct C call.

gh-110190 [https://github.com/python/cpython/issues/110190]: Fix ctypes structs with array on SPARC by setting MAX_STRUCT_SIZE to 32 in stgdict. Patch by Jakub Kulik

gh-118033 [https://github.com/python/cpython/issues/118033]: Fix dataclasses.dataclass() not creating a __weakref__ slot when subclassing typing.Generic.

gh-117766 [https://github.com/python/cpython/issues/117766]: Always use str() to print choices in argparse.

gh-106531 [https://github.com/python/cpython/issues/106531]: In importlib.resources, sync with importlib_resources 6.3.2 [https://importlib-resources.readthedocs.io/en/latest/history.html#v6-3-2], including: MultiplexedPath now expects Traversable paths, deprecating string arguments to MultiplexedPath; Enabled support for resources in namespace packages in zip files; Fixed NotADirectoryError when calling files on a subdirectory of a namespace package.

gh-115937 [https://github.com/python/cpython/issues/115937]: Removed extra preprocessing for the __signature__ attribute: the code just check if it’s a inspect.Signature instance. Patch by Sergey B Kirpichev.

gh-115808 [https://github.com/python/cpython/issues/115808]: Add operator.is_none() and operator.is_not_none() functions.

gh-114264 [https://github.com/python/cpython/issues/114264]: Improve performance of copy.deepcopy() by adding a fast path for atomic types.

gh-113878 [https://github.com/python/cpython/issues/113878]: Add doc parameter to dataclasses.field(), so it can be stored and shown as a documentation / metadata. If @dataclass(slots=True) is used, then the supplied string is availabl in the __slots__ dict. Otherwise, the supplied string is only available in the corresponding dataclasses.Field object.

In order to support this feature we are changing the __slots__ format in dataclasses from tuple to dict when documentation / metadata is present.

gh-113978 [https://github.com/python/cpython/issues/113978]: Ignore warnings on text completion inside REPL.

gh-113008 [https://github.com/python/cpython/issues/113008]: Correct argparse usage output for required, mutually exclusive groups containing a positional argument

gh-108172 [https://github.com/python/cpython/issues/108172]: webbrowser honors OS preferred browser on Linux when its desktop entry name contains the text of a known browser name.

gh-109109 [https://github.com/python/cpython/issues/109109]: You can now get the raw TLS certificate chains from TLS connections via ssl.SSLSocket.get_verified_chain() and ssl.SSLSocket.get_unverified_chain() methods.

Contributed by Mateusz Nowak.

gh-105623 [https://github.com/python/cpython/issues/105623]: Fix performance degradation in logging.handlers.RotatingFileHandler. Patch by Craig Robson.

gh-102450 [https://github.com/python/cpython/issues/102450]: Add missing ISO-8601 24:00 alternative to midnight of next day to datetime.datetime.fromisoformat() and datetime.time.fromisoformat(). Patch by Izan “TizzySaurus” Robinson (tizzysaurus@gmail.com)

gh-103956 [https://github.com/python/cpython/issues/103956]: Fix lack of newline characters in trace module output when line tracing is enabled but source code line for current frame is not available.

gh-92081 [https://github.com/python/cpython/issues/92081]: Fix missing spaces in email headers when the spaces are mixed with encoded 8-bit characters.

gh-103194 [https://github.com/python/cpython/issues/103194]: Prepare Tkinter for C API changes in Tcl 8.7/9.0 to avoid _tkinter.Tcl_Obj being unexpectedly returned instead of bool, str, bytearray, or int.

gh-87106 [https://github.com/python/cpython/issues/87106]: Fixed handling in inspect.Signature.bind() of keyword arguments having the same name as positional-only arguments when a variadic keyword argument (e.g. **kwargs) is present.

gh-103134 [https://github.com/python/cpython/issues/103134]: Add additional methods to proxy objects in the multiprocessing module:

clear() and copy() for proxies of list

fromkeys(), reversed(d), d | {}, {} | d, d |= {'b': 2} for proxies of dict

bpo-45767 [https://bugs.python.org/issue?@action=redirect&bpo=45767]: Fix integer conversion in os.major(), os.minor(), and os.makedev(). Support device numbers larger than 2**63-1. Support non-existent device number (NODEV).

bpo-44864 [https://bugs.python.org/issue?@action=redirect&bpo=44864]: Do not translate user-provided strings in argparse.ArgumentParser.

bpo-41843 [https://bugs.python.org/issue?@action=redirect&bpo=41843]: Solaris now uses os.sendfile() fast-copy syscall for more efficient shutil file copy related functions.

bpo-15987 [https://bugs.python.org/issue?@action=redirect&bpo=15987]: Implemented ast.compare() for comparing two ASTs. Patch by Batuhan Taskaya with some help from Jeremy Hylton.

gh-67693 [https://github.com/python/cpython/issues/67693]: Fix urllib.parse.urlunparse() and urllib.parse.urlunsplit() for URIs with path starting with multiple slashes and no authority. Based on patch by Ashwin Ramaswami.

bpo-14074 [https://bugs.python.org/issue?@action=redirect&bpo=14074]: Fix argparse metavar processing to allow positional arguments to have a tuple metavar.

IDLE

gh-122392 [https://github.com/python/cpython/issues/122392]: Increase currently inadequate vertical spacing for the IDLE browsers (path, module, and stack) on high-resolution monitors.

gh-112938 [https://github.com/python/cpython/issues/112938]: Fix uninteruptable hang when Shell gets rapid continuous output.

gh-122482 [https://github.com/python/cpython/issues/122482]: Change About IDLE to direct users to discuss.python.org instead of the now unused idle-dev email and mailing list.

gh-78889 [https://github.com/python/cpython/issues/78889]: Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes, which are all private.

gh-120083 [https://github.com/python/cpython/issues/120083]: Add explicit black IDLE Hovertip foreground color needed for recent macOS. Fixes Sonoma showing unreadable white on pale yellow. Patch by John Riggles.

gh-120104 [https://github.com/python/cpython/issues/120104]: Fix padding in config and search dialog windows in IDLE.

Documentation

gh-124872 [https://github.com/python/cpython/issues/124872]: Added definitions for context, current context, and context management protocol, updated related definitions to be consistent, and expanded the documentation for contextvars.Context.

gh-125018 [https://github.com/python/cpython/issues/125018]: The importlib.metadata documentation now includes semantic cross-reference targets for the significant documented APIs. This means intersphinx references like importlib.metadata.version() will now work as expected.

gh-124720 [https://github.com/python/cpython/issues/124720]: Update “Using Python on a Mac” section of the “Python Setup and Usage” document and include information on installing free-threading support.

gh-124457 [https://github.com/python/cpython/issues/124457]: Remove coverity scan from the CPython repo. It has not been used since 2020 and is currently unmaintained.

gh-116622 [https://github.com/python/cpython/issues/116622]: Add an Android platform guide, and flag modules not available on Android.

gh-123976 [https://github.com/python/cpython/issues/123976]: Refresh docs around custom providers.

gh-70870 [https://github.com/python/cpython/issues/70870]: Clarified the dual usage of the term “free variable” (both the formal meaning of any reference to names defined outside the local scope, and the narrower pragmatic meaning of nonlocal variables named in co_freevars).

gh-121277 [https://github.com/python/cpython/issues/121277]: Writers of CPython’s documentation can now use next as the version for the versionchanged, versionadded, deprecated directives.

gh-117765 [https://github.com/python/cpython/issues/117765]: Improved documentation for unittest.mock.patch.dict()

gh-121749 [https://github.com/python/cpython/issues/121749]: Fix documentation for PyModule_AddObjectRef().

gh-120012 [https://github.com/python/cpython/issues/120012]: Clarify the behaviours of multiprocessing.Queue.empty() and multiprocessing.SimpleQueue.empty() on closed queues. Patch by Bénédikt Tran.

gh-119574 [https://github.com/python/cpython/issues/119574]: Added some missing environment variables to the output of --help-env.

bpo-34008 [https://bugs.python.org/issue?@action=redirect&bpo=34008]: The Py_Main() documentation moved from the “Very High Level API” section to the “Initialization and Finalization” section.

Also make it explicit that we expect Py_Main to typically be called instead of Py_Initialize rather than after it (since Py_Main makes its own call to Py_Initialize). Document that calling both is supported but is version dependent on which settings will be applied correctly.

Core and Builtins

gh-124375 [https://github.com/python/cpython/issues/124375]: Fix a crash in the free threading build when the GC runs concurrently with a new thread starting.

gh-125221 [https://github.com/python/cpython/issues/125221]: Fix possible race condition when calling __reduce_ex__() for the first time in the free threading build.

gh-125174 [https://github.com/python/cpython/issues/125174]: Make the handling of reference counts of immortal objects more robust. Immortal objects with reference counts that deviate from their original reference count by up to a billion (half a billion on 32 bit builds) are still counted as immortal.

gh-125039 [https://github.com/python/cpython/issues/125039]: Make this_instr and prev_instr const in cases generator.

gh-125008 [https://github.com/python/cpython/issues/125008]: Fix tokenize.untokenize() producing invalid syntax for double braces preceded by certain escape characters.

gh-124871 [https://github.com/python/cpython/issues/124871]: Fix compiler bug (in some versions of 3.13) where an assertion fails during reachability analysis.

gh-123378 [https://github.com/python/cpython/issues/123378]: Fix a crash in the __str__() method of UnicodeError objects when the UnicodeError.start and UnicodeError.end values are invalid or out-of-range. Patch by Bénédikt Tran.

gh-118093 [https://github.com/python/cpython/issues/118093]: Improve the experimental JIT compiler’s ability to stay “on trace” when encountering highly-biased branches.

gh-124642 [https://github.com/python/cpython/issues/124642]: Fixed scalability issue in free-threaded builds for lock-free reads from dictionaries in multi-threaded scenarios

gh-116510 [https://github.com/python/cpython/issues/116510]: Fix a crash caused by immortal interned strings being shared between sub-interpreters that use basic single-phase init. In that case, the string can be used by an interpreter that outlives the interpreter that created and interned it. For interpreters that share obmalloc state, also share the interned dict with the main interpreter.

gh-116510 [https://github.com/python/cpython/issues/116510]: Fix a bug that can cause a crash when sub-interpreters use “basic” single-phase extension modules. Shared objects could refer to PyGC_Head nodes that had been freed as part of interpreter cleanup.

gh-119180 [https://github.com/python/cpython/issues/119180]: The __main__ module no longer always contains an __annotations__ dictionary in its global namespace.

gh-124547 [https://github.com/python/cpython/issues/124547]: When deallocating an object with inline values whose __dict__ is still live: if memory allocation for the inline values fails, clear the dictionary. Prevents an interpreter crash.

gh-124513 [https://github.com/python/cpython/issues/124513]: Fix a crash in FrameLocalsProxy constructor: check the number of arguments. Patch by Victor Stinner.

gh-124442 [https://github.com/python/cpython/issues/124442]: Fix nondeterminism in compilation by sorting the value of __static_attributes__. Patch by kp2pml30.

gh-124285 [https://github.com/python/cpython/issues/124285]: Fix bug where bool(a) can be invoked more than once during the evaluation of a compound boolean expression.

gh-123856 [https://github.com/python/cpython/issues/123856]: Fix PyREPL failure when a keyboard interrupt is triggered after using a history search

gh-65961 [https://github.com/python/cpython/issues/65961]: Deprecate the setting and using __package__ and __cached__.

gh-119726 [https://github.com/python/cpython/issues/119726]: The JIT now generates more efficient code for calls to C functions resulting in up to 0.8% memory savings and 1.5% speed improvement on AArch64. Patch by Diego Russo.

gh-122878 [https://github.com/python/cpython/issues/122878]: Use the pager binary, if available (e.g. on Debian and derivatives), to display REPL help().

gh-124188 [https://github.com/python/cpython/issues/124188]: Fix reading and decoding a line from the source file witn non-UTF-8 encoding for syntax errors raised in the compiler.

gh-124027 [https://github.com/python/cpython/issues/124027]: Support <page up>, <page down>, and <delete> keys in the Python REPL when $TERM is set to vt100.

gh-124022 [https://github.com/python/cpython/issues/124022]: Fix bug where docstring is removed from classes in interactive mode.

gh-123958 [https://github.com/python/cpython/issues/123958]: docstrings are now removed from the optimized AST in optimization level 2.

gh-123923 [https://github.com/python/cpython/issues/123923]: The f_executable field in the internal _PyInterpreterFrame struct now uses a tagged pointer. Profilers and debuggers that uses this field should clear the least significant bit to recover the PyObject* pointer.

gh-77894 [https://github.com/python/cpython/issues/77894]: Fix possible crash in the garbage collector when it tries to break a reference loop containing a memoryview object. Now a memoryview object can only be cleared if there are no buffers that refer it.

gh-120221 [https://github.com/python/cpython/issues/120221]: asyncio REPL is now again properly recognizing KeyboardInterrupts. Display of exceptions raised in secondary threads is fixed.

gh-119310 [https://github.com/python/cpython/issues/119310]: Allow the new interactive shell to read history files written with the editline library that use unicode-escaped entries. Patch by aorcajo and Łukasz Langa.

gh-123572 [https://github.com/python/cpython/issues/123572]: Fix key mappings for various F-keys in Windows for the new REPL. Patch by devdanzin

gh-123614 [https://github.com/python/cpython/issues/123614]: Add turtle.save() to easily save Turtle drawings as PostScript files. Patch by Marie Roald and Yngve Mardal Moe.

gh-123339 [https://github.com/python/cpython/issues/123339]: Setting the __module__ attribute for a class now removes the __firstlineno__ item from the type’s dict, so they will no longer be inconsistent.

gh-119034 [https://github.com/python/cpython/issues/119034]: Change <page up> and <page down> keys of the Python REPL to history search forward/backward. Patch by Victor Stinner.

gh-123562 [https://github.com/python/cpython/issues/123562]: Improve SyntaxError message for using case ... as ... with not a name.

gh-123545 [https://github.com/python/cpython/issues/123545]: Fix a double decref in rare cases on experimental JIT builds.

gh-123484 [https://github.com/python/cpython/issues/123484]: Fix _Py_DebugOffsets for long objects to be relative to the start of the object rather than the start of a subobject.

gh-123446 [https://github.com/python/cpython/issues/123446]: Fix empty function name in TypeError when builtin magic methods are used without the required args.

gh-123440 [https://github.com/python/cpython/issues/123440]: Improve SyntaxError message for using except as with not a name.

gh-116017 [https://github.com/python/cpython/issues/116017]: Improved JIT memory consumption by periodically freeing memory used by infrequently-executed code. This change is especially likely to improve the memory footprint of long-running programs.

gh-123344 [https://github.com/python/cpython/issues/123344]: Add AST optimizations for type parameter defaults.

gh-123321 [https://github.com/python/cpython/issues/123321]: Prevent Parser/myreadline race condition from segfaulting on multi-threaded use. Patch by Bar Harel and Amit Wienner.

gh-123177 [https://github.com/python/cpython/issues/123177]: Fix a bug causing stray prompts to appear in the middle of wrapped lines in the new REPL.

gh-122982 [https://github.com/python/cpython/issues/122982]: Extend the deprecation period for bool inversion (~) by two years.

gh-123271 [https://github.com/python/cpython/issues/123271]: Make concurrent iterations over the same zip() iterator safe under free-threading.

gh-123275 [https://github.com/python/cpython/issues/123275]: Support -X gil=1 and PYTHON_GIL=1 on non-free-threaded builds.

gh-123177 [https://github.com/python/cpython/issues/123177]: Deactivate line wrap in the Apple Terminal via a ANSI escape code. Patch by Pablo Galindo

gh-123229 [https://github.com/python/cpython/issues/123229]: Fix valgrind warning by initializing the f-string buffers to 0 in the tokenizer. Patch by Pablo Galindo

gh-122298 [https://github.com/python/cpython/issues/122298]: Restore printout of GC stats when gc.set_debug(gc.DEBUG_STATS) is called. This feature was accidentally removed when implementing incremental GC.

gh-121804 [https://github.com/python/cpython/issues/121804]: Correctly show error locations when a SyntaxError is raised in the basic REPL. Patch by Sergey B Kirpichev.

gh-115776 [https://github.com/python/cpython/issues/115776]: Enables inline values (Python’s equivalent of hidden classes) on any class who’s instances are of a fixed size.

gh-123142 [https://github.com/python/cpython/issues/123142]: Fix too-wide source location in exception tracebacks coming from broken iterables in comprehensions.

gh-123048 [https://github.com/python/cpython/issues/123048]: Fix a bug where pattern matching code could emit a JUMP_FORWARD with no source location.

gh-118093 [https://github.com/python/cpython/issues/118093]: Break up CALL_ALLOC_AND_ENTER_INIT into micro-ops and relax requirement for exact args, in order to increase the amount of code supported by tier 2.

gh-123123 [https://github.com/python/cpython/issues/123123]: Fix displaying SyntaxError exceptions covering multiple lines. Patch by Pablo Galindo

gh-123083 [https://github.com/python/cpython/issues/123083]: Fix a potential use-after-free in STORE_ATTR_WITH_HINT.

gh-123022 [https://github.com/python/cpython/issues/123022]: Fix crash in free-threaded build when calling Py_Initialize() from a non-main thread.

gh-118093 [https://github.com/python/cpython/issues/118093]: Add three specializations for CALL_KW:

CALL_KW_PY for calls to Python functions

CALL_KW_BOUND_METHOD for calls to bound methods

CALL_KW_NON_PY for all other calls

gh-122821 [https://github.com/python/cpython/issues/122821]: Make sure that branches in while statements have consistent offsets for sys.monitoring. while statements are now compiled with a simple jump at the end of the body, instead of duplicating the test.

gh-122907 [https://github.com/python/cpython/issues/122907]: Building with HAVE_DYNAMIC_LOADING now works as well as it did in 3.12. Existing deficiences will be addressed separately. (See https://github.com/python/cpython/issues/122950.)

gh-122888 [https://github.com/python/cpython/issues/122888]: Fix crash on certain calls to str() with positional arguments of the wrong type. Patch by Jelle Zijlstra.

gh-118093 [https://github.com/python/cpython/issues/118093]: Improve the experimental JIT’s handling of polymorphic code.

gh-122697 [https://github.com/python/cpython/issues/122697]: Fixed memory leaks at interpreter shutdown in the free-threaded build, and also reporting of leaked memory blocks via -X showrefcount.

gh-116622 [https://github.com/python/cpython/issues/116622]: Fix Android stdout and stderr messages being truncated or lost.

gh-122527 [https://github.com/python/cpython/issues/122527]: Fix a crash that occurred when a PyStructSequence was deallocated after its type’s dictionary was cleared by the GC. The type’s tp_basicsize now accounts for non-sequence fields that aren’t included in the Py_SIZE of the sequence.

gh-122445 [https://github.com/python/cpython/issues/122445]: Add only fields which are modified via self.* to __static_attributes__.

gh-122417 [https://github.com/python/cpython/issues/122417]: In the free-threaded build, the reference counts for heap type objects are now partially stored in a distributed manner in per-thread arrays. This reduces contention on the heap type’s reference count fields when creating or destroying instances of the same type from multiple threads concurrently.

gh-116090 [https://github.com/python/cpython/issues/116090]: Fix an issue in JIT builds that prevented some for loops from correctly firing RAISE monitoring events.

gh-122300 [https://github.com/python/cpython/issues/122300]: Preserve AST nodes for f-string with single-element format specifiers. Patch by Pablo Galindo

gh-120906 [https://github.com/python/cpython/issues/120906]: frame.f_locals now supports arbitrary hashable objects as keys.

gh-122239 [https://github.com/python/cpython/issues/122239]: When a list, tuple or dict with too many elements is unpacked, show the actual length in the error message.

gh-122245 [https://github.com/python/cpython/issues/122245]: Detection of writes to __debug__ is moved from the compiler’s codegen stage to the symtable. This means that these errors are now detected even in code that is optimized away before codegen (such as assertions with the -O command line option).

gh-122234 [https://github.com/python/cpython/issues/122234]: Specializations for sums with float and complex inputs in sum() now always use compensated summation. Also, for integer items in above specializations: PyLong_AsDouble() is used, instead of PyLong_AsLongAndOverflow(). Patch by Sergey B Kirpichev.

gh-122208 [https://github.com/python/cpython/issues/122208]: Dictionary watchers now only deliver the PyDict_EVENT_ADDED event when the insertion is in a known good state to succeed.

gh-122160 [https://github.com/python/cpython/issues/122160]: Remove the BUILD_CONST_KEY_MAP opcode. Use BUILD_MAP instead.

gh-122029 [https://github.com/python/cpython/issues/122029]: Emit c_call events in sys.setprofile() when a PyMethodObject pointing to a PyCFunction is called.

gh-122026 [https://github.com/python/cpython/issues/122026]: Fix a bug that caused the tokenizer to not correctly identify mismatched parentheses inside f-strings in some situations. Patch by Pablo Galindo

gh-99108 [https://github.com/python/cpython/issues/99108]: Python’s hashlib now unconditionally uses the vendored HACL* library for Blake2. Python no longer accepts libb2 as an optional dependency for Blake2.

We refreshed HACL* to the latest version, and now vendor HACL*’s 128-bit and 256-bit wide vector implementations for Blake2, which are used on x86/x64 toolchains when the required CPU features are available at runtime.

HACL*’s 128-bit wide vector implementation of Blake2 can also run on ARM NEON and Power8, but lacking evidence of a performance gain, these are not enabled (yet).

gh-121999 [https://github.com/python/cpython/issues/121999]: The default extraction filter for the tarfile module is now set to 'data'.

gh-121860 [https://github.com/python/cpython/issues/121860]: Fix crash when rematerializing a managed dictionary after it was deleted.

gh-121795 [https://github.com/python/cpython/issues/121795]: Improve performance of set membership testing, set.remove() and set.discard() when the argument is a set.

gh-121814 [https://github.com/python/cpython/issues/121814]: Fixed the SegFault when PyEval_SetTrace() is used with no Python frame on stack.

gh-121295 [https://github.com/python/cpython/issues/121295]: Fix PyREPL console getting into a blocked state after interrupting a long paste

gh-121794 [https://github.com/python/cpython/issues/121794]: Fix bug in free-threaded Python where a resurrected object could lead to a negative ref count assertion failure.

gh-121657 [https://github.com/python/cpython/issues/121657]: Improve the SyntaxError message if the user tries to use yield from outside a function.

gh-121609 [https://github.com/python/cpython/issues/121609]: Fix pasting of characters containing unicode character joiners in the new REPL. Patch by Marta Gomez Macias

gh-121297 [https://github.com/python/cpython/issues/121297]: Previously, incorrect usage of await or asynchronous comprehensions in code removed by the -O option was not flagged by the Python compiler. Now, such code raises SyntaxError. Patch by Jelle Zijlstra.

gh-117482 [https://github.com/python/cpython/issues/117482]: Unexpected slot wrappers are no longer created for builtin static types in subinterpreters.

gh-121562 [https://github.com/python/cpython/issues/121562]: Optimized performance of hex_from_char by replacing switch-case with a lookup table

gh-121499 [https://github.com/python/cpython/issues/121499]: Fix a bug affecting how multi-line history was being rendered in the new REPL after interacting with the new screen cache. Patch by Pablo Galindo

gh-121497 [https://github.com/python/cpython/issues/121497]: Fix a bug that was preventing the REPL to correctly respect the history when an input hook was set. Patch by Pablo Galindo

gh-121012 [https://github.com/python/cpython/issues/121012]: Tier 2 execution now ensures that list iterators remain exhausted, once they become exhausted.

gh-121439 [https://github.com/python/cpython/issues/121439]: Allow tuples of length 20 in the freelist to be reused.

gh-121288 [https://github.com/python/cpython/issues/121288]: ValueError messages for list.index(), range.index(), deque.index(), deque.remove() and ShareableList.index() no longer contain the repr of the searched value (which can be arbitrary large) and are consistent with error messages for other index() and remove() methods.

gh-121368 [https://github.com/python/cpython/issues/121368]: Fix race condition in _PyType_Lookup in the free-threaded build due to a missing memory fence. This could lead to _PyType_Lookup returning incorrect results on arm64.

gh-121149 [https://github.com/python/cpython/issues/121149]: Added specialization for summation of complexes, this also improves accuracy of builtin sum() for such inputs. Patch by Sergey B Kirpichev.

gh-121130 [https://github.com/python/cpython/issues/121130]: Fix f-strings with debug expressions in format specifiers. Patch by Pablo Galindo

gh-121381 [https://github.com/python/cpython/issues/121381]: Remove subprocess._USE_VFORK escape hatch code and documentation. It was added just in case, and doesn’t have any known cases that require it.

gh-119726 [https://github.com/python/cpython/issues/119726]: Optimize code layout for calls to C functions from the JIT on AArch64. Patch by Diego Russo.

gh-121115 [https://github.com/python/cpython/issues/121115]: PyLong_AsNativeBytes() no longer uses __index__() methods by default. The Py_ASNATIVEBYTES_ALLOW_INDEX flag has been added to allow it.

gh-120838 [https://github.com/python/cpython/issues/120838]: Py_Finalize() and Py_FinalizeEx() now always run with the main interpreter active.

gh-113433 [https://github.com/python/cpython/issues/113433]: Subinterpreters now get cleaned up automatically during runtime finalization.

gh-119726 [https://github.com/python/cpython/issues/119726]: Improve the speed and memory use of C function calls from JIT code on AArch64. Patch by Diego Russo

gh-116017 [https://github.com/python/cpython/issues/116017]: Simplify the warmup mechanism used for “side exits” in JIT code, resulting in slightly better performance and slightly lower memory usage for most platforms.

gh-98442 [https://github.com/python/cpython/issues/98442]: Fix too wide source locations of the cleanup instructions of a with statement.

gh-120754 [https://github.com/python/cpython/issues/120754]: Reduce the number of system calls invoked when reading a whole file (ex. open('a.txt').read()). For a sample program that reads the contents of the 400+ .rst files in the cpython repository Doc folder, there is an over 10% reduction in system call count.

gh-119462 [https://github.com/python/cpython/issues/119462]: Make sure that invariants of type versioning are maintained: * Superclasses always have their version number assigned before subclasses * The version tag is always zero if the tag is not valid. * The version tag is always non-if the tag is valid.

gh-120437 [https://github.com/python/cpython/issues/120437]: Fix _CHECK_STACK_SPACE optimization problems introduced in gh-118322 [https://github.com/python/cpython/issues/118322].

gh-120722 [https://github.com/python/cpython/issues/120722]: Correctly set the bytecode position on return instructions within lambdas. Patch by Jelle Zijlstra.

gh-120367 [https://github.com/python/cpython/issues/120367]: Fix bug where compiler creates a redundant jump during pseudo-op replacement. Can only happen with a synthetic AST that has a try on the same line as the instruction following the exception handler.

gh-120507 [https://github.com/python/cpython/issues/120507]: Remove the BEFORE_WITH and BEFORE_ASYNC_WITH instructions. Add the new LOAD_SPECIAL instruction. Generate code for with and async with statements using the new instruction.

gh-113993 [https://github.com/python/cpython/issues/113993]: Strings interned with sys.intern() are again garbage-collected when no longer used, as per the documentation. Strings interned with the C function PyUnicode_InternInPlace() are still immortal. Internals of the string interning mechanism have been changed. This may affect performance and identities of str objects.

gh-120485 [https://github.com/python/cpython/issues/120485]: Add an override of allow_reuse_port on classes subclassing socketserver.TCPServer where allow_reuse_address is also overridden.

gh-120384 [https://github.com/python/cpython/issues/120384]: Fix an array out of bounds crash in list_ass_subscript, which could be invoked via some specifically tailored input: including concurrent modification of a list object, where one thread assigns a slice and another clears it.

gh-120367 [https://github.com/python/cpython/issues/120367]: Fix crash in compiler on code with redundant NOPs and JUMPs which show up after exception handlers are moved to the end of the code.

gh-120380 [https://github.com/python/cpython/issues/120380]: Fix Python implementation of pickle.Pickler for bytes and bytearray objects when using protocol version 5. Patch by Bénédikt Tran.

gh-120397 [https://github.com/python/cpython/issues/120397]: Improve the throughput by up to two times for the str.count(), bytes.count() and bytearray.count() methods for counting single characters.

gh-120221 [https://github.com/python/cpython/issues/120221]: Deliver real signals on Ctrl-C and Ctrl-Z in the new REPL. Patch by Pablo Galindo

gh-120346 [https://github.com/python/cpython/issues/120346]: Respect PYTHON_BASIC_REPL when running in interactive inspect mode (python -i). Patch by Pablo Galindo

gh-93691 [https://github.com/python/cpython/issues/93691]: Fix source locations of instructions generated for the iterator of a for statement.

gh-120198 [https://github.com/python/cpython/issues/120198]: Fix a crash when multiple threads read and write to the same __class__ of an object concurrently.

gh-120298 [https://github.com/python/cpython/issues/120298]: Fix use-after free in list_richcompare_impl which can be invoked via some specifically tailored evil input.

gh-119666 [https://github.com/python/cpython/issues/119666]: Fix a compiler crash in the case where two comprehensions in class scope both reference __class__.

gh-119726 [https://github.com/python/cpython/issues/119726]: JIT: Re-use trampolines on AArch64 when creating stencils. Patch by Diego Russo

gh-120225 [https://github.com/python/cpython/issues/120225]: Fix crash in compiler on empty block at end of exception handler.

gh-93691 [https://github.com/python/cpython/issues/93691]: Fix source locations of instructions generated for with statements.

gh-120097 [https://github.com/python/cpython/issues/120097]: FrameLocalsProxy now subclasses collections.abc.Mapping and can be matched as a mapping in match statements

gh-120080 [https://github.com/python/cpython/issues/120080]: Direct call to the int.__round__() now accepts None as a valid argument.

gh-119933 [https://github.com/python/cpython/issues/119933]: Improve SyntaxError messages for invalid expressions in a type parameters bound, a type parameter constraint tuple or a default type parameter. Patch by Bénédikt Tran.

gh-119724 [https://github.com/python/cpython/issues/119724]: Reverted improvements to error messages for elif/else statements not matching any valid statements, which made in hard to locate the syntax errors inside those elif/else blocks.

gh-119879 [https://github.com/python/cpython/issues/119879]: String search is now slightly faster for certain cases. It now utilizes last character gap (good suffix rule) for two-way periodic needles.

gh-119842 [https://github.com/python/cpython/issues/119842]: Honor PyOS_InputHook() in the new REPL. Patch by Pablo Galindo

gh-119180 [https://github.com/python/cpython/issues/119180]: classmethod() and staticmethod() now wrap the __annotations__ and __annotate__ attributes of their underlying callable lazily. See PEP 649 [https://peps.python.org/pep-0649/]. Patch by Jelle Zijlstra.

gh-119821 [https://github.com/python/cpython/issues/119821]: Fix execution of annotation scopes within classes when globals is set to a non-dict. Patch by Jelle Zijlstra.

gh-118934 [https://github.com/python/cpython/issues/118934]: Make PyEval_GetLocals return borrowed reference

gh-119740 [https://github.com/python/cpython/issues/119740]: Remove the previously-deprecated delegation of int() to __trunc__().

gh-119689 [https://github.com/python/cpython/issues/119689]: Generate stack effect metadata for pseudo instructions from bytecodes.c.

gh-109218 [https://github.com/python/cpython/issues/109218]: complex() accepts now a string only as a positional argument. Passing a complex number as the “real” or “imag” argument is deprecated; it should only be passed as a single positional argument.

gh-119548 [https://github.com/python/cpython/issues/119548]: Add a clear command to the REPL. Patch by Pablo Galindo

gh-111999 [https://github.com/python/cpython/issues/111999]: Fix the signature of str.format_map().

gh-119560 [https://github.com/python/cpython/issues/119560]: An invalid assert in beta 1 has been removed. The assert would fail if PyState_FindModule() was used in an extension module’s init function before the module def had been initialized.

gh-119369 [https://github.com/python/cpython/issues/119369]: Fix deadlock during thread deletion in free-threaded build, which could occur when the GIL was enabled at runtime.

gh-119525 [https://github.com/python/cpython/issues/119525]: Fix deadlock involving _PyType_Lookup() cache in the free-threaded build when the GIL is dynamically enabled at runtime.

gh-119258 [https://github.com/python/cpython/issues/119258]: Eliminate type version guards in the tier two interpreter.

Note that setting the tp_version_tag manually (which has never been supported) may result in crashes.

gh-119311 [https://github.com/python/cpython/issues/119311]: Fix bug where names are unexpectedly mangled in the bases of generic classes.

gh-119395 [https://github.com/python/cpython/issues/119395]: Fix bug where names appearing after a generic class are mangled as if they are in the generic class.

gh-119372 [https://github.com/python/cpython/issues/119372]: Correct invalid corner cases in complex division (resulted in (nan+nanj) output), e.g. 1/complex('(inf+infj)'). Patch by Sergey B Kirpichev.

gh-119180 [https://github.com/python/cpython/issues/119180]: Evaluation of annotations is now deferred. See PEP 649 [https://peps.python.org/pep-0649/] for details.

gh-119180 [https://github.com/python/cpython/issues/119180]: Replace LOAD_ASSERTION_ERROR opcode with LOAD_COMMON_CONSTANT and add support for NotImplementedError.

gh-119213 [https://github.com/python/cpython/issues/119213]: Non-builtin modules built with argument clinic were crashing if used in a subinterpreter before the main interpreter. The objects that were causing the problem by leaking between interpreters carelessly have been fixed.

gh-119011 [https://github.com/python/cpython/issues/119011]: Fixes type.__type_params__ to return an empty tuple instead of a descriptor.

gh-118692 [https://github.com/python/cpython/issues/118692]: Avoid creating unnecessary StopIteration instances for monitoring.

gh-119180 [https://github.com/python/cpython/issues/119180]: Add an __annotate__ attribute to functions, classes, and modules as part of PEP 649 [https://peps.python.org/pep-0649/]. Patch by Jelle Zijlstra.

gh-119049 [https://github.com/python/cpython/issues/119049]: Fix displaying the source line for warnings created by the C API if the warnings module had not yet been imported.

gh-119057 [https://github.com/python/cpython/issues/119057]: Improve ZeroDivisionError error message. Now, all error messages are harmonized: all /, //, and % operations just use “division by zero” message. And 0 ** -1 operation uses “zero to a negative power”.

gh-118844 [https://github.com/python/cpython/issues/118844]: Fix build failures when configuring with both --disable-gil and --enable-experimental-jit.

gh-118921 [https://github.com/python/cpython/issues/118921]: Add copy() method for FrameLocalsProxy which returns a snapshot dict for local variables.

gh-117657 [https://github.com/python/cpython/issues/117657]: Fix data races on the field that stores a pointer to the interpreter’s main thread that occur in free-threaded builds.

gh-118750 [https://github.com/python/cpython/issues/118750]: If the C version of the decimal module is available, int(str) now uses it to supply an asymptotically much faster conversion. However, this only applies if the string contains over about 2 million digits.

gh-118767 [https://github.com/python/cpython/issues/118767]: Using NotImplemented in a boolean context now raises TypeError. Contributed by Jelle Zijlstra.

gh-118561 [https://github.com/python/cpython/issues/118561]: Fix race condition in free-threaded build where list.extend() could expose uninitialised memory to concurrent readers.

gh-117139 [https://github.com/python/cpython/issues/117139]: Convert the Python evaluation stack to use internal stack references. The purpose is to support tagged pointers. In PEP 703 [https://peps.python.org/pep-0703/], this will allow for its form of deferred reference counting. For both the default and free-threaded builds, this sets up the infrastructure for unboxed integers in the future.

gh-115801 [https://github.com/python/cpython/issues/115801]: Raise TypeError when passing a string to difflib.unified_diff() and difflib.context_diff().

gh-117558 [https://github.com/python/cpython/issues/117558]: Improve error messages when a string, bytes or bytearray object of length 1 is expected.

gh-117195 [https://github.com/python/cpython/issues/117195]: Avoid assertion failure for debug builds when calling object.__sizeof__(1)

gh-116022 [https://github.com/python/cpython/issues/116022]: Improve the __repr__() output of AST nodes.

gh-114091 [https://github.com/python/cpython/issues/114091]: Changed the error message for awaiting something that can’t be awaited from “object <type> can’t be used in an await expression” to “’<type>’ object can’t be awaited”.

gh-113190 [https://github.com/python/cpython/issues/113190]: Py_Finalize() now deletes all interned strings.

gh-84978 [https://github.com/python/cpython/issues/84978]: Add class methods float.from_number() and complex.from_number().

gh-95144 [https://github.com/python/cpython/issues/95144]: Improve the error message from a in b when b is not a container to mention the term “container”.

bpo-24766 [https://bugs.python.org/issue?@action=redirect&bpo=24766]: Fix handling of doc argument to subclasses of property.

C API

gh-123961 [https://github.com/python/cpython/issues/123961]: Convert the curses.window static type exposed by the PyCursesWindow_Type macro in Include/py_curses.h to a heap type. Patch by Bénédikt Tran.

gh-124502 [https://github.com/python/cpython/issues/124502]: Add PyUnicode_Equal() function to the limited C API: test if two strings are equal. Patch by Victor Stinner.

gh-124296 [https://github.com/python/cpython/issues/124296]: PyDictObject no longer maintains a private version tag field ma_version_tag per PEP 699 [https://peps.python.org/pep-0699/]. This field was originally added in Python 3.6 (PEP 509 [https://peps.python.org/pep-0509/]) and deprecated in Python 3.12.

gh-124160 [https://github.com/python/cpython/issues/124160]: Fix crash when importing modules containing state and single-phase initialization in a subinterpreter.

gh-124153 [https://github.com/python/cpython/issues/124153]: Add PyType_GetBaseByToken() and Py_tp_token slot for easier type checking, related to PEP 489 [https://peps.python.org/pep-0489/] and PEP 630 [https://peps.python.org/pep-0630/].

gh-124127 [https://github.com/python/cpython/issues/124127]: In the limited C API 3.14 and newer, Py_REFCNT() is now implemented as an opaque function call to hide implementation details. Patch by Victor Stinner.

gh-123880 [https://github.com/python/cpython/issues/123880]: Fixed a bug that prevented circular imports of extension modules that use single-phase initialization.

gh-123909 [https://github.com/python/cpython/issues/123909]: PyType_FromSpec(), PyType_FromSpecWithBases() and PyType_FromModuleAndSpec() will now fail if the metaclass of the new type has custom tp_new.

gh-107954 [https://github.com/python/cpython/issues/107954]: Add functions to configure the Python initialization (PEP 741 [https://peps.python.org/pep-0741/]):

PyInitConfig_Create()

PyInitConfig_Free()

PyInitConfig_GetError()

PyInitConfig_GetExitCode()

PyInitConfig_HasOption()

PyInitConfig_GetInt()

PyInitConfig_GetStr()

PyInitConfig_GetStrList()

PyInitConfig_FreeStrList()

PyInitConfig_SetInt()

PyInitConfig_SetStr()

PyInitConfig_SetStrList()

PyInitConfig_AddModule()

Py_InitializeFromInitConfig()

Patch by Victor Stinner.

gh-107954 [https://github.com/python/cpython/issues/107954]: Add functions to get and set the current runtime Python configuration:

PyConfig_Get()

PyConfig_GetInt()

PyConfig_Set()

PyConfig_Names()

Patch by Victor Stinner.

gh-123465 [https://github.com/python/cpython/issues/123465]: Py_RELATIVE_OFFSET is now allowed in PyMemberDef for the special offset member "__vectorcalloffset__", as well as the discouraged special offset members "__dictoffset__" and "__weaklistoffset__"

gh-100554 [https://github.com/python/cpython/issues/100554]: Added a slot Py_tp_vectorcall to set tp_vectorcall via the PyType_FromSpec() function family. Limited API extensions can use this feature to provide more efficient vector call-based implementation of __new__ and __init__.

gh-122854 [https://github.com/python/cpython/issues/122854]: Add Py_HashBuffer() to compute and return the hash value of a buffer. Patch by Antoine Pitrou and Victor Stinner.

gh-122728 [https://github.com/python/cpython/issues/122728]: Fix PyEval_GetLocals() to avoid SystemError (“bad argument to internal function”). Patch by Victor Stinner.

gh-116622 [https://github.com/python/cpython/issues/116622]: Make PyObject_Print work around a bug in Android and OpenBSD which prevented it from throwing an exception when trying to write to a read-only stream.

gh-105201 [https://github.com/python/cpython/issues/105201]: Add PyIter_NextItem() to replace PyIter_Next(), which has an ambiguous return value. Patch by Irit Katriel and Erlend Aasland.

gh-121489 [https://github.com/python/cpython/issues/121489]: Export private _PyBytes_Join() again.

gh-121645 [https://github.com/python/cpython/issues/121645]: Add PyBytes_Join(sep, iterable) function, similar to sep.join(iterable) in Python. Patch by Victor Stinner.

gh-89364 [https://github.com/python/cpython/issues/89364]: Export the PySignal_SetWakeupFd() function. Previously, the function was documented but it couldn’t be used in 3rd party code. Patch by Victor Stinner.

gh-113993 [https://github.com/python/cpython/issues/113993]: PyUnicode_InternInPlace() no longer prevents its argument from being garbage collected.

Several functions that take char * are now documented as possibly preventing string objects from being garbage collected; refer to their documentation for details: PyUnicode_InternFromString(), PyDict_SetItemString(), PyObject_SetAttrString(), PyObject_DelAttrString(), PyUnicode_InternFromString(), and PyModule_Add* convenience functions.

gh-113601 [https://github.com/python/cpython/issues/113601]: Removed debug build assertions related to interning strings, which were falsely triggered by stable ABI extensions.

gh-112136 [https://github.com/python/cpython/issues/112136]: Restore the private _PyArg_Parser structure and the private _PyArg_ParseTupleAndKeywordsFast() function, previously removed in Python 3.13 alpha 1. Patch by Victor Stinner.

gh-120642 [https://github.com/python/cpython/issues/120642]: Remove the private _Py_CODEUNIT type from the public C API. The internal pycore_code.h header should now be used to get this internal type. Patch by Victor Stinner.

gh-120858 [https://github.com/python/cpython/issues/120858]: PyDict_Next() no longer locks the dictionary in the free-threaded build. The locking needs to be done by the caller around the entire iteration loop.

gh-120642 [https://github.com/python/cpython/issues/120642]: Remove the following unstable functions:

PyUnstable_Replace_Executor()

PyUnstable_SetOptimizer()

PyUnstable_GetOptimizer()

PyUnstable_GetExecutor()

PyUnstable_Optimizer_NewCounter()

PyUnstable_Optimizer_NewUOpOptimizer()

Patch by Victor Stinner.

gh-120389 [https://github.com/python/cpython/issues/120389]: Add new functions to convert C <stdint.h> numbers from/to Python int:

PyLong_FromInt32()

PyLong_FromUInt32()

PyLong_FromInt64()

PyLong_FromUInt64()

PyLong_AsInt32()

PyLong_AsUInt32()

PyLong_AsInt64()

PyLong_AsUInt64()

Patch by Victor Stinner.

gh-120600 [https://github.com/python/cpython/issues/120600]: In the limited C API 3.14 and newer, Py_TYPE() is now implemented as an opaque function call to hide implementation details. Patch by Victor Stinner.

gh-70278 [https://github.com/python/cpython/issues/70278]: PyUnicode_FromFormat() no longer produces the ending \ufffd character for truncated C string when use precision with %s and %V. It now truncates the string before the start of truncated multibyte sequences.

gh-119771 [https://github.com/python/cpython/issues/119771]: Set errno in _Py_c_pow() on overflows. Patch by Sergey B Kirpichev.

gh-119182 [https://github.com/python/cpython/issues/119182]: Add a new PyUnicodeWriter API to create a Python str object:

PyUnicodeWriter_Create().

PyUnicodeWriter_Discard().

PyUnicodeWriter_Finish().

PyUnicodeWriter_WriteChar().

PyUnicodeWriter_WriteUTF8().

PyUnicodeWriter_WriteUCS4().

PyUnicodeWriter_WriteWideChar().

PyUnicodeWriter_WriteStr().

PyUnicodeWriter_WriteRepr().

PyUnicodeWriter_WriteSubstring().

PyUnicodeWriter_Format().

PyUnicodeWriter_DecodeUTF8Stateful().

Patch by Victor Stinner.

gh-119613 [https://github.com/python/cpython/issues/119613]: Soft deprecate the Py_MEMCPY macro: use directly memcpy() instead. Patch by Victor Stinner.

gh-119775 [https://github.com/python/cpython/issues/119775]: Creating immutable types with mutable bases was deprecated since 3.12 and now raises a TypeError.

gh-119585 [https://github.com/python/cpython/issues/119585]: Fix crash when a thread state that was created by PyGILState_Ensure() calls a destructor that during PyThreadState_Clear() that calls back into PyGILState_Ensure() and PyGILState_Release(). This might occur when in the free-threaded build or when using thread-local variables whose destructors call PyGILState_Ensure().

gh-119613 [https://github.com/python/cpython/issues/119613]: Macros Py_IS_NAN, Py_IS_INFINITY and Py_IS_FINITE are soft deprecated.

gh-119336 [https://github.com/python/cpython/issues/119336]: Restore the removed _PyLong_NumBits() function. It is used by the pywin32 project. Patch by Ethan Smith

gh-119344 [https://github.com/python/cpython/issues/119344]: The critical section API is now public as part of the non-limited C API.

gh-119333 [https://github.com/python/cpython/issues/119333]: Add PyContext_AddWatcher() and PyContext_ClearWatcher() APIs to register callbacks to receive notification on enter and exit of context objects.

gh-119247 [https://github.com/python/cpython/issues/119247]: Added Py_BEGIN_CRITICAL_SECTION_SEQUENCE_FAST and Py_END_CRITICAL_SECTION_SEQUENCE_FAST macros to make it possible to use PySequence_Fast APIs safely when free-threaded, and update str.join to work without the GIL using them.

gh-111389 [https://github.com/python/cpython/issues/111389]: Add PyHASH_MULTIPLIER constant: prime multiplier used in string and various other hashes. Patch by Victor Stinner.

gh-118771 [https://github.com/python/cpython/issues/118771]: Several C declarations with names that didn’t start with the Py or _Py prefixes, which were added by mistake in 3.13 alpha and beta releases, were moved to internal headers.

gh-116984 [https://github.com/python/cpython/issues/116984]: Make mimalloc includes relative to the current file to avoid embedders or extensions needing to include Internal/mimalloc if they are already including internal CPython headers.

gh-118789 [https://github.com/python/cpython/issues/118789]: Add PyUnstable_Object_ClearWeakRefsNoCallbacks(), which clears weakrefs without calling their callbacks.

gh-118789 [https://github.com/python/cpython/issues/118789]: Restore _PyWeakref_ClearRef that was previously removed in Python 3.13 alpha 1.

gh-117511 [https://github.com/python/cpython/issues/117511]: Make the PyMutex public in the non-limited C API.

gh-116560 [https://github.com/python/cpython/issues/116560]: Add PyLong_GetSign() function. Patch by Sergey B Kirpichev.

gh-97588 [https://github.com/python/cpython/issues/97588]: Fix creating bitfields in ctypes structures and unions. Fields no longer overlap.

gh-87135 [https://github.com/python/cpython/issues/87135]: Attempting to acquire the GIL after runtime finalization has begun in a different thread now causes the thread to hang rather than terminate, which avoids potential crashes or memory corruption caused by attempting to terminate a thread that is running code not specifically designed to support termination. In most cases this hanging is harmless since the process will soon exit anyway.

The PyThread_exit_thread function is now deprecated. Its behavior is inconsistent across platforms, and it can only be used safely in the unlikely case that every function in the entire call stack has been designed to support the platform-dependent termination mechanism. It is recommended that users of this function change their design to not require thread termination. In the unlikely case that thread termination is needed and can be done safely, users may migrate to calling platform-specific APIs such as pthread_exit (POSIX) or _endthreadex (Windows) directly.

bpo-34008 [https://bugs.python.org/issue?@action=redirect&bpo=34008]: Added Py_IsInitialized to the list of APIs that are safe to call before the interpreter is initialized, and updated the embedding tests to cover it.

Build

gh-125269 [https://github.com/python/cpython/issues/125269]: Fix detection of whether -latomic is needed when cross-compiling CPython using the configure script.

gh-123990 [https://github.com/python/cpython/issues/123990]: Remove WITH_FREELISTS macro and --without-freelists build configuration

gh-124102 [https://github.com/python/cpython/issues/124102]: Update internal documentation under PCbuild, so it now correctly states that Windows requires VS2017 or later and Python 3.10 or later

gh-124043 [https://github.com/python/cpython/issues/124043]: Building using --with-trace-refs is (temporarily) disallowed when the GIL is disabled.

gh-123418 [https://github.com/python/cpython/issues/123418]: Updated Android build to use OpenSSL 3.0.15.

gh-123297 [https://github.com/python/cpython/issues/123297]: Propagate the value of LDFLAGS to LDCXXSHARED in sysconfig. Patch by Pablo Galindo

gh-121634 [https://github.com/python/cpython/issues/121634]: Allow for specifying the target compile triple for WASI.

gh-122578 [https://github.com/python/cpython/issues/122578]: Use WASI SDK 24 for testing.

gh-116622 [https://github.com/python/cpython/issues/116622]: Rename build variable MODULE_LDFLAGS back to LIBPYTHON, as it’s used by package build systems (e.g. Meson).

gh-118943 [https://github.com/python/cpython/issues/118943]: Fix an issue where the experimental JIT could be built several times by the make regen-all target, leading to possible race conditions on heavily parallelized builds.

gh-121996 [https://github.com/python/cpython/issues/121996]: Introduce ./configure –disable-safety and –enable-slower-safety options. Patch by Donghee Na.

gh-120522 [https://github.com/python/cpython/issues/120522]: Added a --with-app-store-compliance option to patch out known issues with macOS/iOS App Store review processes.

gh-120371 [https://github.com/python/cpython/issues/120371]: Support WASI SDK 22 by explicitly skipping functions that are just stubs in wasi-libc.

gh-121731 [https://github.com/python/cpython/issues/121731]: Fix mimalloc compile error on GNU/Hurd

gh-121487 [https://github.com/python/cpython/issues/121487]: Fix deprecation warning for ATOMIC_VAR_INIT in mimalloc.

gh-121467 [https://github.com/python/cpython/issues/121467]: Fix a Makefile bug that prevented mimalloc header files from being installed.

gh-121103 [https://github.com/python/cpython/issues/121103]: On POSIX systems, excluding macOS framework installs, the lib directory for the free-threaded build now includes a “t” suffix to avoid conflicts with a co-located default build installation.

gh-120831 [https://github.com/python/cpython/issues/120831]: The default minimum iOS version was increased to 13.0.

gh-121082 [https://github.com/python/cpython/issues/121082]: Fix build failure when the developer use --enable-pystats arguments in configuration command after #118450.

gh-120671 [https://github.com/python/cpython/issues/120671]: Fix failing configure tests due to a missing space when appending to CFLAGS.

gh-120602 [https://github.com/python/cpython/issues/120602]: Correctly handle LLVM installs with LLVM_VERSION_SUFFIX when building with --enable-experimental-jit.

gh-120688 [https://github.com/python/cpython/issues/120688]: On WASI in debug mode, Python is now built with compiler flag -O3 instead of -Og, to support more recursive calls. Patch by Victor Stinner.

gh-118943 [https://github.com/python/cpython/issues/118943]: Fix a possible race condition affecting parallel builds configured with --enable-experimental-jit, in which FileNotFoundError could be caused by another process already moving jit_stencils.h.new to jit_stencils.h.

gh-120326 [https://github.com/python/cpython/issues/120326]: On Windows, fix build error when --disable-gil and --experimental-jit options are combined.

gh-120291 [https://github.com/python/cpython/issues/120291]: Make the python-config shell script compatible with non-bash shells.

gh-113565 [https://github.com/python/cpython/issues/113565]: Improve curses and curses.panel dependency checks in configure.

gh-119729 [https://github.com/python/cpython/issues/119729]: On POSIX systems, the pkg-config (.pc) filenames now include the ABI flags, which may include debug (“d”) and free-threaded (“t”). For example: * python-3.14.pc (default, non-debug build) * python-3.14d.pc (default, debug build) * python-3.14t.pc (free-threaded build)

gh-119400 [https://github.com/python/cpython/issues/119400]: make_ssl_certs, the script that prepares certificate data for the test suite, now allows specifying expiration dates.

gh-115119 [https://github.com/python/cpython/issues/115119]: Fall back to the bundled libmpdec if a system version cannot be found.

gh-119132 [https://github.com/python/cpython/issues/119132]: Update sys.version to identify whether the build is default build or free-threading build. Patch By Donghee Na.

gh-118836 [https://github.com/python/cpython/issues/118836]: Fix an AssertionError when building with --enable-experimental-jit and the compiler emits a SHT_NOTE section.

gh-118943 [https://github.com/python/cpython/issues/118943]: Fix a possible race condition affecting parallel builds configured with --enable-experimental-jit, in which compilation errors could be caused by an incompletely-generated header file.

Python 3.13.0 beta 1

Release date: 2024-05-08

Security

gh-116741 [https://github.com/python/cpython/issues/116741]: Update bundled libexpat to 2.6.2

gh-117233 [https://github.com/python/cpython/issues/117233]: Detect BLAKE2, SHA3, Shake, & truncated SHA512 support in the OpenSSL-ish libcrypto library at build time. This allows hashlib to be used with libraries that do not to support every algorithm that upstream OpenSSL does.

Core and Builtins

gh-118414 [https://github.com/python/cpython/issues/118414]: Add instrumented opcodes to YIELD_VALUE assertion for tracing cases.

gh-117953 [https://github.com/python/cpython/issues/117953]: When a builtin or extension module is imported for the first time, while a subinterpreter is active, the module’s init function is now run by the main interpreter first before import continues in the subinterpreter. Consequently, single-phase init modules now fail in an isolated subinterpreter without the init function running under that interpreter, whereas before it would run under the subinterpreter before failing, potentially leaving behind global state and callbacks and otherwise leaving the module in an inconsistent state.

gh-117549 [https://github.com/python/cpython/issues/117549]: Don’t use designated initializer syntax in inline functions in internal headers. They cause problems for C++ or MSVC users who aren’t yet using the latest C++ standard (C++20). While internal, pycore_backoff.h, is included (indirectly, via pycore_code.h) by some key 3rd party software that does so for speed.

gh-95382 [https://github.com/python/cpython/issues/95382]: Improve performance of json.dumps() and json.dump() when using the argument indent. Depending on the data the encoding using json.dumps() with indent can be up to 2 to 3 times faster.

gh-116322 [https://github.com/python/cpython/issues/116322]: In --disable-gil builds, the GIL will be enabled while loading C extension modules. If the module indicates that it supports running without the GIL, the GIL will be disabled once loading is complete. Otherwise, the GIL will remain enabled for the remainder of the interpreter’s lifetime. This behavior does not apply if the GIL has been explicitly enabled or disabled with PYTHON_GIL or -Xgil.

gh-118513 [https://github.com/python/cpython/issues/118513]: Fix incorrect UnboundLocalError when two comprehensions in the same function both reference the same name, and in one comprehension the name is bound while in the other it’s an implicit global.

gh-118518 [https://github.com/python/cpython/issues/118518]: Allow the Linux perf support to work without frame pointers using perf’s advanced JIT support. The feature is activated when using the PYTHON_PERF_JIT_SUPPORT environment variable or when running Python with -Xperf_jit. Patch by Pablo Galindo.

gh-117514 [https://github.com/python/cpython/issues/117514]: Add sys._is_gil_enabled() function that returns whether the GIL is currently enabled. In the default build it always returns True because the GIL is always enabled. In the free-threaded build, it may return True or False.

gh-118164 [https://github.com/python/cpython/issues/118164]: Break a loop between the Python implementation of the decimal module and the Python code for integer to string conversion. Also optimize integer to string conversion for values in the range from 9_000 to 135_000 decimal digits.

gh-118473 [https://github.com/python/cpython/issues/118473]: Fix sys.set_asyncgen_hooks() not to be partially set when raising TypeError.

gh-118465 [https://github.com/python/cpython/issues/118465]: Compiler populates the new __firstlineno__ field on a class with the line number of the first line of the class definition.

gh-118492 [https://github.com/python/cpython/issues/118492]: Fix an issue where the type cache can expose a previously accessed attribute when a finalizer is run.

gh-117714 [https://github.com/python/cpython/issues/117714]: update async_generator.athrow().close() and async_generator.asend().close() to close their section of the underlying async generator

gh-111201 [https://github.com/python/cpython/issues/111201]: The interactive interpreter is now implemented in Python, which allows for a number of new features like colors, multiline input, history viewing, and paste mode. Contributed by Pablo Galindo, Łukasz Langa and Lysandros Nikolaou based on code from the PyPy project.

gh-74929 [https://github.com/python/cpython/issues/74929]: Implement PEP 667: converted FrameType.f_locals and PyFrame_GetLocals() to return a write-through proxy object when the frame refers to a function or comprehension.

gh-116767 [https://github.com/python/cpython/issues/116767]: Fix crash in compiler on ‘async with’ that has many context managers.

gh-118335 [https://github.com/python/cpython/issues/118335]: Change how to use the tier 2 interpreter. Instead of running Python with -X uops or setting the environment variable PYTHON_UOPS=1, this choice is now made at build time by configuring with --enable-experimental-jit=interpreter.

Beware! This changes the environment variable to enable or disable micro-ops to PYTHON_JIT. The old PYTHON_UOPS is no longer used.

gh-118306 [https://github.com/python/cpython/issues/118306]: Update JIT compilation to use LLVM 18

gh-118160 [https://github.com/python/cpython/issues/118160]: Annotation scopes within classes can now contain comprehensions. However, such comprehensions are not inlined into their parent scope at runtime. Patch by Jelle Zijlstra.

gh-118272 [https://github.com/python/cpython/issues/118272]: Fix bug where generator.close does not free the generator frame’s locals.

gh-118216 [https://github.com/python/cpython/issues/118216]: Don’t consider __future__ imports with dots before the module name.

gh-118074 [https://github.com/python/cpython/issues/118074]: Make sure that the Executor objects in the COLD_EXITS array aren’t assumed to be GC-able (which would access bytes outside the object).

gh-107674 [https://github.com/python/cpython/issues/107674]: Lazy load frame line number to improve performance of tracing

gh-118082 [https://github.com/python/cpython/issues/118082]: Improve SyntaxError message for imports without names, like in from x import and import cases. It now points out to users that import expects at least one name after it.

gh-118090 [https://github.com/python/cpython/issues/118090]: Improve SyntaxError message for empty type param brackets.

gh-117958 [https://github.com/python/cpython/issues/117958]: Added a get_jit_code() method to access JIT compiled machine code from the UOp Executor when the experimental JIT is enabled. Patch by Anthony Shaw.

gh-117901 [https://github.com/python/cpython/issues/117901]: Add option for compiler’s codegen to save nested instruction sequences for introspection.

gh-116622 [https://github.com/python/cpython/issues/116622]: Redirect stdout and stderr to system log when embedded in an Android app.

gh-109118 [https://github.com/python/cpython/issues/109118]: annotation scope within class scopes can now contain lambdas.

gh-117894 [https://github.com/python/cpython/issues/117894]: Prevent agen.aclose() objects being re-used after .throw().

gh-117881 [https://github.com/python/cpython/issues/117881]: prevent concurrent access to an async generator via athrow().throw() or asend().throw()

gh-117536 [https://github.com/python/cpython/issues/117536]: Fix a RuntimeWarning when calling agen.aclose().throw(Exception).

gh-117755 [https://github.com/python/cpython/issues/117755]: Fix mimalloc allocator for huge memory allocation (around 8,589,934,592 GiB) on s390x. Patch by Victor Stinner.

gh-117750 [https://github.com/python/cpython/issues/117750]: Fix issue where an object’s dict would get out of sync with the object’s internal values when being cleared. obj.__dict__.clear() now clears the internal values, but leaves the dict attached to the object.

gh-117431 [https://github.com/python/cpython/issues/117431]: Improve the performance of the following bytes and bytearray methods by adapting them to the METH_FASTCALL calling convention:

count()

find()

index()

rfind()

rindex()

gh-117709 [https://github.com/python/cpython/issues/117709]: Speed up calls to str() with positional-only argument, by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Erlend Aasland.

gh-117680 [https://github.com/python/cpython/issues/117680]: Give _PyInstructionSequence a Python interface and use it in tests.

gh-115776 [https://github.com/python/cpython/issues/115776]: Statically allocated objects are, by definition, immortal so must be marked as such regardless of whether they are in extension modules or not.

gh-117385 [https://github.com/python/cpython/issues/117385]: Remove unhandled PY_MONITORING_EVENT_BRANCH and PY_MONITORING_EVENT_EXCEPTION_HANDLED events from sys.settrace().

gh-116322 [https://github.com/python/cpython/issues/116322]: Extension modules may indicate to the runtime that they can run without the GIL. Multi-phase init modules do so by calling providing Py_MOD_GIL_NOT_USED for the Py_mod_gil slot, while single-phase init modules call PyUnstable_Module_SetGIL(mod, Py_MOD_GIL_NOT_USED) from their init function.

gh-116129 [https://github.com/python/cpython/issues/116129]: Implement PEP 696 [https://peps.python.org/pep-0696/], adding support for defaults on type parameters. Patch by Jelle Zijlstra.

gh-93502 [https://github.com/python/cpython/issues/93502]: Add two new functions to the C-API, PyRefTracer_SetTracer() and PyRefTracer_GetTracer(), that allows to track object creation and destruction the same way the tracemalloc module does. Patch by Pablo Galindo

gh-107674 [https://github.com/python/cpython/issues/107674]: Improved the performance of sys.settrace() significantly

gh-95754 [https://github.com/python/cpython/issues/95754]: Improve the error message when a script shadowing a module from the standard library causes AttributeError to be raised. Similarly, improve the error message when a script shadowing a third party module attempts to access an attribute from that third party module while still initialising.

gh-99180 [https://github.com/python/cpython/issues/99180]: Elide uninformative traceback indicators in return and simple assignment statements. Patch by Pablo Galindo.

gh-105879 [https://github.com/python/cpython/issues/105879]: Allow the globals and locals arguments to exec() and eval() to be passed as keywords.

Library

gh-118418 [https://github.com/python/cpython/issues/118418]: A DeprecationWarning is now emitted if you fail to pass a value to the new type_params parameter of typing._eval_type() or typing.ForwardRef._evaluate(). (Using either of these private and undocumented functions is discouraged to begin with, but failing to pass a value to the type_params parameter may lead to incorrect behaviour on Python 3.12 or newer.)

gh-118660 [https://github.com/python/cpython/issues/118660]: Add an optional second type parameter to typing.ContextManager and typing.AsyncContextManager, representing the return types of __exit__() and __aexit__() respectively. This parameter defaults to bool | None.

gh-118650 [https://github.com/python/cpython/issues/118650]: The enum module allows method named _repr_* to be defined on Enum types.

gh-118648 [https://github.com/python/cpython/issues/118648]: Add type parameter defaults to typing.Generator and typing.AsyncGenerator.

gh-101137 [https://github.com/python/cpython/issues/101137]: Mime type text/x-rst is now supported by mimetypes.

gh-118164 [https://github.com/python/cpython/issues/118164]: The Python implementation of the decimal module could appear to hang in relatively small power cases (like 2**117) if context precision was set to a very high value. A different method to check for exactly representable results is used now that doesn’t rely on computing 10**precision (which could be effectively too large to compute).

gh-111744 [https://github.com/python/cpython/issues/111744]: breakpoint() and pdb.set_trace() now enter the debugger immediately after the call rather than before the next line is executed.

gh-118500 [https://github.com/python/cpython/issues/118500]: Add pdb support for zipapps

gh-118406 [https://github.com/python/cpython/issues/118406]: Add signature for sqlite3.Connection objects.

gh-101732 [https://github.com/python/cpython/issues/101732]: Use a Y2038 compatible openssl time function when available.

gh-118404 [https://github.com/python/cpython/issues/118404]: Fix inspect.signature() for non-comparable callables.

gh-118402 [https://github.com/python/cpython/issues/118402]: Fix inspect.signature() for the result of the functools.cmp_to_key() call.

gh-116622 [https://github.com/python/cpython/issues/116622]: On Android, sysconfig.get_platform now returns the format specified by PEP 738 [https://peps.python.org/pep-0738/].

gh-118285 [https://github.com/python/cpython/issues/118285]: Allow to specify the signature of custom callable instances of extension type by the __text_signature__ attribute. Specify signatures of operator.attrgetter, operator.itemgetter, and operator.methodcaller instances.

gh-118314 [https://github.com/python/cpython/issues/118314]: Fix an edge case in binascii.a2b_base64() strict mode, where excessive padding is not detected when no padding is necessary.

gh-118271 [https://github.com/python/cpython/issues/118271]: Add the PhotoImage methods read() to read an image from a file and data() to get the image data. Add background and grayscale parameters to PhotoImage method write().

gh-118225 [https://github.com/python/cpython/issues/118225]: Add the PhotoImage method copy_replace() to copy a region from one image to other image, possibly with pixel zooming and/or subsampling. Add from_coords parameter to PhotoImage methods copy(), zoom() and subsample(). Add zoom and subsample parameters to PhotoImage method copy().

gh-118221 [https://github.com/python/cpython/issues/118221]: Fix a bug where sqlite3.Connection.iterdump() could fail if a custom row factory was used. Patch by Erlend Aasland.

gh-118013 [https://github.com/python/cpython/issues/118013]: Fix regression introduced in gh-103193 [https://github.com/python/cpython/issues/103193] that meant that calling inspect.getattr_static() on an instance would cause a strong reference to that instance’s class to persist in an internal cache in the inspect module. This caused unexpected memory consumption if the class was dynamically created, the class held strong references to other objects which took up a significant amount of memory, and the cache contained the sole strong reference to the class. The fix for the regression leads to a slowdown in getattr_static(), but the function should still be significantly faster than it was in Python 3.11. Patch by Alex Waygood.

gh-118218 [https://github.com/python/cpython/issues/118218]: Speed up itertools.pairwise() in the common case by up to 1.8x.

gh-117486 [https://github.com/python/cpython/issues/117486]: Improve the behavior of user-defined subclasses of ast.AST. Such classes will now require no changes in the usual case to conform with the behavior changes of the ast module in Python 3.13. Patch by Jelle Zijlstra.

gh-90848 [https://github.com/python/cpython/issues/90848]: Fixed unittest.mock.create_autospec() to configure parent mock with keyword arguments.

gh-118168 [https://github.com/python/cpython/issues/118168]: Fix incorrect argument substitution when typing.Unpack is used with the builtin tuple. typing.Unpack now raises TypeError when used with certain invalid types. Patch by Jelle Zijlstra.

gh-118131 [https://github.com/python/cpython/issues/118131]: Add command-line interface for the random module. Patch by Hugo van Kemenade.

gh-118107 [https://github.com/python/cpython/issues/118107]: Fix zipimport reading of ZIP64 files with file entries that are too big or offset too far.

gh-102511 [https://github.com/python/cpython/issues/102511]: Fix os.path.normpath() for UNC paths on Windows. Speed up os.path.splitroot() with a native implementation.

gh-117535 [https://github.com/python/cpython/issues/117535]: Change the unknown filename of warnings from sys to <sys> to clarify that it’s not a real filename.

gh-114053 [https://github.com/python/cpython/issues/114053]: Fix erroneous NameError when calling typing.get_type_hints() on a class that made use of PEP 695 [https://peps.python.org/pep-0695/] type parameters in a module that had from __future__ import annotations at the top of the file. Patch by Alex Waygood.

gh-116931 [https://github.com/python/cpython/issues/116931]: Add parameter fileobj check for tarfile.TarFile.addfile()

gh-117995 [https://github.com/python/cpython/issues/117995]: Don’t raise DeprecationWarning when a sequence of parameters is used to bind indexed, nameless placeholders. See also gh-100668 [https://github.com/python/cpython/issues/100668].

gh-80361 [https://github.com/python/cpython/issues/80361]: Fix TypeError in email.message.Message.get_payload() when the charset is RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html] encoded.

gh-86650 [https://github.com/python/cpython/issues/86650]: Fix IndexError when parse some emails with invalid Message-ID (including one-off addresses generated by Microsoft Outlook).

gh-117691 [https://github.com/python/cpython/issues/117691]: Improve the error messages emitted by tarfile deprecation warnings relating to PEP 706. If a filter argument is not provided to extract() or extractall, the deprecation warning now points to the line in the user’s code where the relevant function was called. Patch by Alex Waygood.

gh-115874 [https://github.com/python/cpython/issues/115874]: Fixed a possible segfault during garbage collection of _asyncio.FutureIter objects. Patch by Savannah Ostrowski.

gh-115060 [https://github.com/python/cpython/issues/115060]: Speed up pathlib.Path.glob() by omitting an initial is_dir() call. As a result of this change, glob() can no longer raise OSError.

gh-77102 [https://github.com/python/cpython/issues/77102]: site module now parses .pth file with UTF-8 first, and locale encoding if UnicodeDecodeError happened. It supported only locale encoding before.

gh-76785 [https://github.com/python/cpython/issues/76785]: We’ve exposed the low-level _interpreters module for the sake of the PyPI implementation of PEP 734 [https://peps.python.org/pep-0734/]. It was sometimes available as the _xxsubinterpreters module and was formerly used only for testing. For the most part, it should be considered an internal module, like _thread and _imp. See https://discuss.python.org/t/pep-734-multiple-interpreters-in-the-stdlib/41147/26.

gh-115060 [https://github.com/python/cpython/issues/115060]: Speed up pathlib.Path.glob() by not scanning directories for non-wildcard pattern segments.

gh-117727 [https://github.com/python/cpython/issues/117727]: Speed up pathlib.Path.iterdir() by using os.scandir() internally.

gh-117586 [https://github.com/python/cpython/issues/117586]: Speed up pathlib.Path.walk() by working with strings internally.

gh-117722 [https://github.com/python/cpython/issues/117722]: Change the new multi-separator support in asyncio.StreamReader.readuntil() to only accept tuples of separators rather than arbitrary iterables.

gh-117692 [https://github.com/python/cpython/issues/117692]: Fixes a bug when doctest.DocTestFinder was failing on wrapped builtin_function_or_method.

gh-117348 [https://github.com/python/cpython/issues/117348]: Largely restored import time performance of configparser by avoiding dataclasses.

gh-117641 [https://github.com/python/cpython/issues/117641]: Speedup os.path.commonpath() on Unix.

gh-117663 [https://github.com/python/cpython/issues/117663]: Fix _simple_enum to detect aliases when multiple arguments are present but only one is the member value.

gh-117636 [https://github.com/python/cpython/issues/117636]: Speedup os.path.join().

gh-117618 [https://github.com/python/cpython/issues/117618]: Support package.module as filename for break command of pdb

gh-102247 [https://github.com/python/cpython/issues/102247]: the status codes enum with constants in http.HTTPStatus are updated to include the names from RFC9110. This RFC includes some HTTP statuses previously only used for WEBDAV and assigns more generic names to them.

The old constants are preserved for backwards compatibility.

gh-117607 [https://github.com/python/cpython/issues/117607]: Speedup os.path.relpath().

gh-117586 [https://github.com/python/cpython/issues/117586]: Speed up pathlib.Path.glob() by working with strings internally.

gh-117225 [https://github.com/python/cpython/issues/117225]: Add colour to doctest output. Patch by Hugo van Kemenade.

gh-117566 [https://github.com/python/cpython/issues/117566]: ipaddress.IPv6Address.is_loopback() will now return True for IPv4-mapped loopback addresses, i.e. addresses in the ::ffff:127.0.0.0/104 address space.

gh-117546 [https://github.com/python/cpython/issues/117546]: Fix issue where os.path.realpath() stopped resolving symlinks after encountering a symlink loop on POSIX.

gh-116720 [https://github.com/python/cpython/issues/116720]: Improved behavior of asyncio.TaskGroup when an external cancellation collides with an internal cancellation. For example, when two task groups are nested and both experience an exception in a child task simultaneously, it was possible that the outer task group would misbehave, because its internal cancellation was swallowed by the inner task group.

In the case where a task group is cancelled externally and also must raise an ExceptionGroup, it will now call the parent task’s cancel() method. This ensures that a asyncio.CancelledError will be raised at the next await, so the cancellation is not lost.

An added benefit of these changes is that task groups now preserve the cancellation count (asyncio.Task.cancelling()).

In order to handle some corner cases, asyncio.Task.uncancel() may now reset the undocumented _must_cancel flag when the cancellation count reaches zero.

gh-117516 [https://github.com/python/cpython/issues/117516]: Add typing.TypeIs, implementing PEP 742 [https://peps.python.org/pep-0742/]. Patch by Jelle Zijlstra.

gh-117503 [https://github.com/python/cpython/issues/117503]: Fix support of non-ASCII user names in bytes paths in os.path.expanduser() on Posix.

gh-117394 [https://github.com/python/cpython/issues/117394]: os.path.ismount() is now 2-3 times faster if the user has permissions.

gh-117313 [https://github.com/python/cpython/issues/117313]: Only treat '\n', '\r' and '\r\n' as line separators in re-folding the email messages. Preserve control characters '\v', '\f', '\x1c', '\x1d' and '\x1e' and Unicode line separators '\x85', '\u2028' and '\u2029' as is.

gh-117142 [https://github.com/python/cpython/issues/117142]: Convert _ctypes to multi-phase initialisation (PEP 489 [https://peps.python.org/pep-0489/]).

gh-66543 [https://github.com/python/cpython/issues/66543]: Add the mimetypes.guess_file_type() function which works with file path. Passing file path instead of URL in guess_type() is soft deprecated.

gh-68583 [https://github.com/python/cpython/issues/68583]: webbrowser CLI: replace getopt with argparse, add long options. Patch by Hugo van Kemenade.

gh-116871 [https://github.com/python/cpython/issues/116871]: Name suggestions for AttributeError and ImportError now only include underscored names if the original name was underscored.

gh-116023 [https://github.com/python/cpython/issues/116023]: Don’t show empty fields (value None or []) in ast.dump() by default. Add show_empty=False parameter to optionally show them.

gh-115961 [https://github.com/python/cpython/issues/115961]: Added name and mode attributes for compressed and archived file-like objects in modules bz2, lzma, tarfile and zipfile. The value of the mode attribute of gzip.GzipFile was changed from integer (1 or 2) to string ('rb' or 'wb'). The value of the mode attribute of the readable file-like object returned by zipfile.ZipFile.open() was changed from 'r' to 'rb'.

gh-82062 [https://github.com/python/cpython/issues/82062]: Fix inspect.signature() to correctly handle parameter defaults on methods in extension modules that use names defined in the module namespace.

gh-83856 [https://github.com/python/cpython/issues/83856]: Honor atexit for all multiprocessing start methods

gh-113081 [https://github.com/python/cpython/issues/113081]: Print colorized exception just like built-in traceback in pdb

gh-112855 [https://github.com/python/cpython/issues/112855]: Speed up pickling of pathlib.PurePath objects. Patch by Barney Gale.

gh-111744 [https://github.com/python/cpython/issues/111744]: Support opcode events in bdb

gh-109617 [https://github.com/python/cpython/issues/109617]: ncurses: fixed a crash that could occur on macOS 13 or earlier when Python was built with Apple Xcode 15’s SDK.

gh-83151 [https://github.com/python/cpython/issues/83151]: Enabled arbitrary statements and evaluations in pdb shell to access the local variables of the current frame, which made it possible for multi-scope code like generators or nested function to work.

gh-110209 [https://github.com/python/cpython/issues/110209]: Add __class_getitem__() to types.GeneratorType and types.CoroutineType for type hinting purposes. Patch by James Hilton-Balfe.

gh-108191 [https://github.com/python/cpython/issues/108191]: The types.SimpleNamespace now accepts an optional positional argument which specifies initial values of attributes as a dict or an iterable of key-value pairs.

gh-62090 [https://github.com/python/cpython/issues/62090]: Fix assertion errors caused by whitespace in metavars or SUPPRESS-ed groups in argparse by simplifying usage formatting. Patch by Ali Hamdan.

gh-102402 [https://github.com/python/cpython/issues/102402]: Adjust logging.LogRecord to use time.time_ns() and fix minor bug related to floating-point math.

gh-100242 [https://github.com/python/cpython/issues/100242]: Bring pure Python implementation functools.partial.__new__ more in line with the C-implementation by not just always checking for the presence of the attribute 'func' on the first argument of partial. Instead, both the Python version and the C version perform an isinstance(func, partial) check on the first argument of partial.

gh-99730 [https://github.com/python/cpython/issues/99730]: HEAD requests are no longer upgraded to GET request during redirects in urllib.

gh-66410 [https://github.com/python/cpython/issues/66410]: Setting the tkinter module global wantobjects to 2 before creating the Tk object or call the wantobjects() method of the Tk object with argument 2 makes now arguments to callbacks registered in the tkinter module to be passed as various Python objects (int, float, bytes, tuple), depending on their internal representation in Tcl, instead of always str. tkinter.wantobjects is now set to 2 by default.

bpo-40943 [https://bugs.python.org/issue?@action=redirect&bpo=40943]: Fix several IndexError when parse emails with truncated Message-ID, address, routes, etc, e.g. example@.

bpo-39324 [https://bugs.python.org/issue?@action=redirect&bpo=39324]: Add mime type mapping for .md <-> text/markdown

bpo-18108 [https://bugs.python.org/issue?@action=redirect&bpo=18108]: shutil.chown() now supports dir_fd and follow_symlinks keyword arguments.

bpo-30988 [https://bugs.python.org/issue?@action=redirect&bpo=30988]: Fix parsing of emails with invalid address headers having a leading or trailing dot. Patch by tsufeki.

bpo-32839 [https://bugs.python.org/issue?@action=redirect&bpo=32839]: Add the after_info() method for Tkinter widgets.

Documentation

gh-117928 [https://github.com/python/cpython/issues/117928]: The minimum Sphinx version required for the documentation is now 6.2.1.

Build

gh-118734 [https://github.com/python/cpython/issues/118734]: Fixes Windows build when invoked directly (not through the build.bat script) without specifying a value for UseTIER2.

gh-115119 [https://github.com/python/cpython/issues/115119]: The configure option --with-system-libmpdec now defaults to yes. The bundled copy of libmpdecimal will be removed in Python 3.15.

gh-117845 [https://github.com/python/cpython/issues/117845]: Fix building against recent libedit versions by detecting readline hook signatures in configure.

gh-116622 [https://github.com/python/cpython/issues/116622]: A testbed project was added to run the test suite on Android.

gh-117645 [https://github.com/python/cpython/issues/117645]: Increase WASI stack size from 512 KiB to 8 MiB and the initial memory from 10 MiB to 20 MiB. Patch by Victor Stinner.

gh-115119 [https://github.com/python/cpython/issues/115119]: configure now uses pkg-config to detect decimal dependencies if the --with-system-libmpdec option is given.

Windows

gh-115119 [https://github.com/python/cpython/issues/115119]: Update Windows installer to use libmpdecimal 4.0.0.

gh-118486 [https://github.com/python/cpython/issues/118486]: os.mkdir() now accepts mode of 0o700 to restrict the new directory to the current user.

gh-118347 [https://github.com/python/cpython/issues/118347]: Fixes launcher updates not being installed.

gh-118293 [https://github.com/python/cpython/issues/118293]: The multiprocessing module now passes the STARTF_FORCEOFFFEEDBACK flag when spawning processes to tell Windows not to change the mouse cursor.

gh-115009 [https://github.com/python/cpython/issues/115009]: Update Windows installer to use SQLite 3.45.3.

gh-90329 [https://github.com/python/cpython/issues/90329]: Suppress the warning displayed on virtual environment creation when the requested and created paths differ only by a short (8.3 style) name. Warnings will continue to be shown if a junction or symlink in the path caused the venv to be created in a different location than originally requested.

gh-117786 [https://github.com/python/cpython/issues/117786]: Fixes virtual environments not correctly launching when created from a Store install.

macOS

gh-115119 [https://github.com/python/cpython/issues/115119]: Update macOS installer to use libmpdecimal 4.0.0.

gh-114099 [https://github.com/python/cpython/issues/114099]: iOS preprocessor symbol usage was made compatible with older macOS SDKs.

gh-115009 [https://github.com/python/cpython/issues/115009]: Update macOS installer to use SQLite 3.45.3.

gh-91629 [https://github.com/python/cpython/issues/91629]: Use ~/.config/fish/conf.d configs and fish_add_path to set PATH when installing for the Fish shell.

IDLE

bpo-34774 [https://bugs.python.org/issue?@action=redirect&bpo=34774]: Use user-selected color theme for Help => IDLE Doc.

C API

gh-118124 [https://github.com/python/cpython/issues/118124]: Fix Py_BUILD_ASSERT and Py_BUILD_ASSERT_EXPR for non-constant expressions: use static_assert() on C11 and newer. Patch by Victor Stinner.

gh-110850 [https://github.com/python/cpython/issues/110850]: Add “Raw” variant of PyTime functions

PyTime_MonotonicRaw()

PyTime_PerfCounterRaw()

PyTime_TimeRaw()

Patch by Victor Stinner.

gh-117987 [https://github.com/python/cpython/issues/117987]: Restore functions removed in Python 3.13 alpha 1:

Py_SetPythonHome()

Py_SetProgramName()

PySys_SetArgvEx()

PySys_SetArgv()

Patch by Victor Stinner.

gh-117929 [https://github.com/python/cpython/issues/117929]: Restore removed PyEval_InitThreads() function. Patch by Victor Stinner.

gh-117534 [https://github.com/python/cpython/issues/117534]: Improve validation logic in the C implementation of datetime.datetime.fromisoformat() to better handle invalid years. Patch by Vlad Efanov.

gh-68114 [https://github.com/python/cpython/issues/68114]: Fixed skipitem()’s handling of the old ‘w’ and ‘w#’ formatters. These are no longer supported and now raise an exception if used.

gh-111997 [https://github.com/python/cpython/issues/111997]: Add a C-API for firing monitoring events.

Python 3.13.0 alpha 6

Release date: 2024-04-09

Core and Builtins

gh-117494 [https://github.com/python/cpython/issues/117494]: Refactored the instruction sequence data structure out of compile.c into instruction_sequence.c.

gh-116968 [https://github.com/python/cpython/issues/116968]: Introduce a unified 16-bit backoff counter type (_Py_BackoffCounter), shared between the Tier 1 adaptive specializer and the Tier 2 optimizer. The API used for adaptive specialization counters is changed but the behavior is (supposed to be) identical.

The behavior of the Tier 2 counters is changed:

There are no longer dynamic thresholds (we never varied these).

All counters now use the same exponential backoff.

The counter for JUMP_BACKWARD starts counting down from 16.

The temperature in side exits starts counting down from 64.

gh-117431 [https://github.com/python/cpython/issues/117431]: Improve the performance of the following bytes and bytearray methods by adapting them to the METH_FASTCALL calling convention:

endswith()

startswith()

gh-117431 [https://github.com/python/cpython/issues/117431]: Improve the performance of the following str methods by adapting them to the METH_FASTCALL calling convention:

count()

endswith()

find()

index()

rfind()

rindex()

startswith()

gh-117411 [https://github.com/python/cpython/issues/117411]: Move PyFutureFeatures to an internal header and make it private.

gh-109120 [https://github.com/python/cpython/issues/109120]: Added handle of incorrect star expressions, e.g f(3, *). Patch by Grigoryev Semyon

gh-117266 [https://github.com/python/cpython/issues/117266]: Fix crashes for certain user-created subclasses of ast.AST. Such classes are now expected to set the _field_types attribute.

gh-99108 [https://github.com/python/cpython/issues/99108]: Updated the hashlib built-in HACL* project [https://github.com/hacl-star/hacl-star] C code from upstream that we use for many implementations when they are not present via OpenSSL in a given build. This also avoids the rare potential for a C symbol name one definition rule linking issue.

gh-117108 [https://github.com/python/cpython/issues/117108]: Change the old space bit of objects in the young generation from 0 to gcstate->visited, so that any objects created during GC will have the old bit set correctly if they get moved into the old generation.

gh-117108 [https://github.com/python/cpython/issues/117108]: The cycle GC now chooses the size of increments based on the total heap size, instead of the rate of object creation. This ensures that it can keep up with growing heaps.

gh-116735 [https://github.com/python/cpython/issues/116735]: For INSTRUMENTED_CALL_FUNCTION_EX, set arg0 to sys.monitoring.MISSING instead of None for CALL event.

gh-113964 [https://github.com/python/cpython/issues/113964]: Starting new threads and process creation through os.fork() are now only prevented once all non-daemon threads exit.

gh-116626 [https://github.com/python/cpython/issues/116626]: Ensure INSTRUMENTED_CALL_FUNCTION_EX always emits CALL

gh-116554 [https://github.com/python/cpython/issues/116554]: list.sort() now exploits more cases of partial ordering, particularly those with long descending runs with sub-runs of equal values. Those are recognized as single runs now (previously, each block of repeated values caused a new run to be created).

gh-114099 [https://github.com/python/cpython/issues/114099]: Added a Loader that can discover extension modules in an iOS-style Frameworks folder.

gh-115775 [https://github.com/python/cpython/issues/115775]: Compiler populates the new __static_attributes__ field on a class with the names of attributes of this class which are accessed through self.X from any function in its body.

gh-115776 [https://github.com/python/cpython/issues/115776]: The array of values, the PyDictValues struct is now embedded in the object during allocation. This provides better performance in the common case, and does not degrade as much when the object’s __dict__ is materialized.

gh-108362 [https://github.com/python/cpython/issues/108362]: Implement an incremental cyclic garbage collector. By collecting the old generation in increments, there is no need for a full heap scan. This can hugely reduce maximum pause time for programs with large heaps.

Reduce the number of generations from three to two. The old generation is split into two spaces, “visited” and “pending”.

Collection happens in two steps:: * An increment is formed from the young generation and a small part of the pending space. * This increment is scanned and the survivors moved to the end of the visited space.

When the collecting space becomes empty, the two spaces are swapped.

gh-109870 [https://github.com/python/cpython/issues/109870]: Dataclasses now calls exec() once per dataclass, instead of once per method being added. This can speed up dataclass creation by up to 20%.

gh-97901 [https://github.com/python/cpython/issues/97901]: Mime type text/rtf is now supported by mimetypes.

bpo-24612 [https://bugs.python.org/issue?@action=redirect&bpo=24612]: Improve the SyntaxError that happens when ‘not’ appears after an operator. Patch by Pablo Galindo

Library

gh-117648 [https://github.com/python/cpython/issues/117648]: Improve performance of os.path.join() and os.path.expanduser().

gh-117584 [https://github.com/python/cpython/issues/117584]: Raise TypeError for non-paths in posixpath.relpath().

gh-117467 [https://github.com/python/cpython/issues/117467]: Preserve mailbox ownership when rewriting in mailbox.mbox.flush(). Patch by Tony Mountifield.

gh-114848 [https://github.com/python/cpython/issues/114848]: Raise FileNotFoundError when getcwd() returns ‘(unreachable)’, which can happen on Linux >= 2.6.36 with glibc < 2.27.

gh-117459 [https://github.com/python/cpython/issues/117459]: asyncio.asyncio.run_coroutine_threadsafe() now keeps the traceback of CancelledError, TimeoutError and InvalidStateError which are raised in the coroutine.

gh-117381 [https://github.com/python/cpython/issues/117381]: Fix error message for ntpath.commonpath().

gh-117337 [https://github.com/python/cpython/issues/117337]: Deprecate undocumented glob.glob0() and glob.glob1() functions. Use glob.glob() and pass a directory to its root_dir argument instead.

gh-117349 [https://github.com/python/cpython/issues/117349]: Optimise several functions in os.path.

gh-117348 [https://github.com/python/cpython/issues/117348]: Refactored configparser.RawConfigParser._read() to reduce cyclometric complexity and improve comprehensibility.

gh-117335 [https://github.com/python/cpython/issues/117335]: Raise TypeError for non-sequences for ntpath.commonpath().

gh-66449 [https://github.com/python/cpython/issues/66449]: configparser.ConfigParser now accepts unnamed sections before named ones, if configured to do so.

gh-88014 [https://github.com/python/cpython/issues/88014]: In documentation of gzip.GzipFile in module gzip, explain data type of optional constructor argument mtime, and recommend mtime = 0 for generating deterministic streams.

gh-117310 [https://github.com/python/cpython/issues/117310]: Fixed an unlikely early & extra Py_DECREF triggered crash in ssl when creating a new _ssl._SSLContext if CPython was built implausibly such that the default cipher list is empty or the SSL library it was linked against reports a failure from its C SSL_CTX_set_cipher_list() API.

gh-117294 [https://github.com/python/cpython/issues/117294]: A DocTestCase now reports as skipped if all examples in the doctest are skipped.

gh-98966 [https://github.com/python/cpython/issues/98966]: In subprocess, raise a more informative message when stdout=STDOUT.

gh-117225 [https://github.com/python/cpython/issues/117225]: doctest: only print “and X failed” when non-zero, don’t pluralise “1 items”. Patch by Hugo van Kemenade.

gh-117205 [https://github.com/python/cpython/issues/117205]: Speed up compileall.compile_dir() by 20% when using multiprocessing by increasing chunksize.

gh-117178 [https://github.com/python/cpython/issues/117178]: Fix regression in lazy loading of self-referential modules, introduced in gh-114781 [https://github.com/python/cpython/issues/114781].

gh-112383 [https://github.com/python/cpython/issues/112383]: Fix dis module’s handling of ENTER_EXECUTOR instructions.

gh-117182 [https://github.com/python/cpython/issues/117182]: Lazy-loading of modules that modify their own __class__ no longer reverts the __class__ to types.ModuleType.

gh-117084 [https://github.com/python/cpython/issues/117084]: Fix zipfile extraction for directory entries with the name containing backslashes on Windows.

gh-117114 [https://github.com/python/cpython/issues/117114]: Make os.path.isdevdrive() available on all platforms. For those that do not offer Dev Drives, it will always return False.

gh-117110 [https://github.com/python/cpython/issues/117110]: Fix a bug that prevents subclasses of typing.Any to be instantiated with arguments. Patch by Chris Fu.

gh-109653 [https://github.com/python/cpython/issues/109653]: Deferred select imports in importlib.metadata and importlib.resources for a 14% speedup.

gh-70647 [https://github.com/python/cpython/issues/70647]: Start the deprecation period for the current behavior of datetime.datetime.strptime() and time.strptime() which always fails to parse a date string with a ValueError involving a day of month such as strptime("02-29", "%m-%d") when a year is not specified and the date happen to be February 29th. This should help avoid users finding new bugs every four years due to a natural mistaken assumption about the API when parsing partial date values.

gh-116987 [https://github.com/python/cpython/issues/116987]: Fixed inspect.findsource() for class code objects.

gh-114099 [https://github.com/python/cpython/issues/114099]: Modify standard library to allow for iOS platform differences.

gh-90872 [https://github.com/python/cpython/issues/90872]: On Windows, subprocess.Popen.wait() no longer calls WaitForSingleObject() with a negative timeout: pass 0 ms if the timeout is negative. Patch by Victor Stinner.

gh-116957 [https://github.com/python/cpython/issues/116957]: configparser: Don’t leave ConfigParser values in an invalid state (stored as a list instead of a str) after an earlier read raised DuplicateSectionError or DuplicateOptionError.

gh-115538 [https://github.com/python/cpython/issues/115538]: _io.WindowsConsoleIO now emit a warning if a boolean value is passed as a filedescriptor argument.

gh-90095 [https://github.com/python/cpython/issues/90095]: Ignore empty lines and comments in .pdbrc

gh-106531 [https://github.com/python/cpython/issues/106531]: Refreshed zipfile._path from zipp 3.18 [https://zipp.readthedocs.io/en/latest/history.html#v3-18-0], providing better compatibility for PyPy, better glob performance for deeply nested zipfiles, and providing internal access to CompleteDirs.inject for use in other tests (like importlib.resources).

gh-63207 [https://github.com/python/cpython/issues/63207]: On Windows, time.time() now uses the GetSystemTimePreciseAsFileTime() clock to have a resolution better than 1 us, instead of the GetSystemTimeAsFileTime() clock which has a resolution of 15.6 ms. Patch by Victor Stinner.

gh-116764 [https://github.com/python/cpython/issues/116764]: Restore support of None and other false values in urllib.parse functions parse_qs() and parse_qsl(). Also, they now raise a TypeError for non-zero integers and non-empty sequences.

gh-116811 [https://github.com/python/cpython/issues/116811]: In PathFinder.invalidate_caches, delegate to MetadataPathFinder.invalidate_caches.

gh-116647 [https://github.com/python/cpython/issues/116647]: Fix recursive child in dataclasses

gh-113171 [https://github.com/python/cpython/issues/113171]: Fixed various false positives and false negatives in

ipaddress.IPv4Address.is_private (see these docs for details)

ipaddress.IPv4Address.is_global

ipaddress.IPv6Address.is_private

ipaddress.IPv6Address.is_global

Also in the corresponding ipaddress.IPv4Network and ipaddress.IPv6Network attributes.

gh-63283 [https://github.com/python/cpython/issues/63283]: In encodings.idna, any capitalization of the ACE prefix (xn--) is now acceptable. Patch by Pepijn de Vos and Zackery Spytz.

gh-71042 [https://github.com/python/cpython/issues/71042]: Add platform.android_ver(), which provides device and OS information on Android.

gh-73468 [https://github.com/python/cpython/issues/73468]: Added new math.fma() function, wrapping C99’s fma() operation: fused multiply-add function. Patch by Mark Dickinson and Victor Stinner.

gh-116608 [https://github.com/python/cpython/issues/116608]: The importlib.resources functions is_resource(), open_binary(), open_text(), path(), read_binary(), and read_text() are un-deprecated, and support subdirectories via multiple positional arguments. The contents() function also allows subdirectories, but remains deprecated.

gh-116484 [https://github.com/python/cpython/issues/116484]: Change automatically generated tkinter.Checkbutton widget names to avoid collisions with automatically generated tkinter.ttk.Checkbutton widget names within the same parent widget.

gh-114314 [https://github.com/python/cpython/issues/114314]: In ctypes, ctype data is now stored in type objects directly rather than in a dict subclass. This is an internal change that should not affect usage.

gh-116401 [https://github.com/python/cpython/issues/116401]: Fix blocking os.fwalk() and shutil.rmtree() on opening named pipe.

gh-71052 [https://github.com/python/cpython/issues/71052]: Implement ctypes.util.find_library() on Android.

gh-90535 [https://github.com/python/cpython/issues/90535]: Fix support of interval values > 1 in logging.TimedRotatingFileHandler for when='MIDNIGHT' and when='Wx'.

gh-113308 [https://github.com/python/cpython/issues/113308]: Remove some internal protected parts from uuid: _has_uuid_generate_time_safe, _netbios_getnode, _ipconfig_getnode, and _load_system_functions. They were unused.

gh-115627 [https://github.com/python/cpython/issues/115627]: Fix the ssl module error handling of connection terminate by peer. It now throws an OSError with the appropriate error code instead of an EOFError.

gh-114847 [https://github.com/python/cpython/issues/114847]: Speed up os.path.realpath() on non-Windows platforms.

gh-114271 [https://github.com/python/cpython/issues/114271]: Fix a race in threading.Thread.join().

threading._MainThread now always represents the main thread of the main interpreter.

PyThreadState.on_delete and PyThreadState.on_delete_data have been removed.

gh-113538 [https://github.com/python/cpython/issues/113538]: Add asyncio.Server.close_clients() and asyncio.Server.abort_clients() methods which allow to more forcefully close an asyncio server.

gh-85287 [https://github.com/python/cpython/issues/85287]: Changes Unicode codecs to return UnicodeEncodeError or UnicodeDecodeError, rather than just UnicodeError.

gh-113548 [https://github.com/python/cpython/issues/113548]: pdb now allows CLI arguments to pdb -m.

gh-112948 [https://github.com/python/cpython/issues/112948]: Make completion of pdb similar to Python REPL

gh-105866 [https://github.com/python/cpython/issues/105866]: Fixed _get_slots bug which caused error when defining dataclasses with slots and a weakref_slot.

gh-96471 [https://github.com/python/cpython/issues/96471]: Add asyncio.Queue termination with shutdown() method.

gh-89739 [https://github.com/python/cpython/issues/89739]: The zipimport module can now read ZIP64 files.

bpo-33533 [https://bugs.python.org/issue?@action=redirect&bpo=33533]: asyncio.as_completed() now returns an object that is both an asynchronous iterator and plain iterator. The new asynchronous iteration pattern allows for easier correlation between prior tasks and their completed results. This is a closer match to concurrent.futures.as_completed()’s iteration pattern. Patch by Justin Arthur.

bpo-27578 [https://bugs.python.org/issue?@action=redirect&bpo=27578]: inspect.getsource() (and related functions) work with empty module files, returning '\n' (or reasonable equivalent) instead of raising OSError. Patch by Kernc.

bpo-37141 [https://bugs.python.org/issue?@action=redirect&bpo=37141]: Accept an iterable of separators in asyncio.StreamReader.readuntil(), stopping when one of them is encountered.

gh-66543 [https://github.com/python/cpython/issues/66543]: Make mimetypes.guess_type() properly parsing of URLs with only a host name, URLs containing fragment or query, and filenames with only a UNC sharepoint on Windows. Based on patch by Dong-hee Na.

bpo-15010 [https://bugs.python.org/issue?@action=redirect&bpo=15010]: unittest.TestLoader.discover() now saves the original value of unittest.TestLoader._top_level_dir and restores it at the end of the call.

Documentation

gh-115977 [https://github.com/python/cpython/issues/115977]: Remove compatibility references to Emscripten.

gh-114099 [https://github.com/python/cpython/issues/114099]: Add an iOS platform guide, and flag modules not available on iOS.

gh-91565 [https://github.com/python/cpython/issues/91565]: Changes to documentation files and config outputs to reflect the new location for reporting bugs - i.e. GitHub rather than bugs.python.org.

Tests

gh-83434 [https://github.com/python/cpython/issues/83434]: Disable JUnit XML output (--junit-xml=FILE command line option) in regrtest when hunting for reference leaks (-R option). Patch by Victor Stinner.

gh-117187 [https://github.com/python/cpython/issues/117187]: Fix XML tests for vanilla Expat <2.6.0.

gh-116333 [https://github.com/python/cpython/issues/116333]: Tests of TLS related things (error codes, etc) were updated to be more lenient about specific error message strings and behaviors as seen in the BoringSSL and AWS-LC forks of OpenSSL.

gh-117089 [https://github.com/python/cpython/issues/117089]: Consolidated tests for importlib.metadata in their own metadata package.

gh-115979 [https://github.com/python/cpython/issues/115979]: Update test_importlib so that it passes under WASI SDK 21.

gh-112536 [https://github.com/python/cpython/issues/112536]: Add –tsan to test.regrtest for running TSAN tests in reasonable execution times. Patch by Donghee Na.

gh-116307 [https://github.com/python/cpython/issues/116307]: Added import helper isolated_modules as CleanImport does not remove modules imported during the context. Use it in importlib.resources tests to avoid leaving mod around to impede importlib.metadata tests.

Build

gh-114736 [https://github.com/python/cpython/issues/114736]: Have WASI builds use WASI SDK 21.

gh-115983 [https://github.com/python/cpython/issues/115983]: Skip building test modules that must be built as shared under WASI.

gh-71052 [https://github.com/python/cpython/issues/71052]: Add Android build script and instructions.

Windows

gh-117267 [https://github.com/python/cpython/issues/117267]: Ensure DirEntry.stat().st_ctime behaves consistently with os.stat() during the deprecation period of st_ctime by containing the same value as st_birthtime. After the deprecation period, st_ctime will be the metadata change time (or unavailable through DirEntry), and only st_birthtime will contain the creation time.

gh-116195 [https://github.com/python/cpython/issues/116195]: Improves performance of os.getppid() by using an alternate system API when available. Contributed by vxiiduu.

gh-88494 [https://github.com/python/cpython/issues/88494]: On Windows, time.monotonic() now uses the QueryPerformanceCounter() clock to have a resolution better than 1 us, instead of the GetTickCount64() clock which has a resolution of 15.6 ms. Patch by Victor Stinner.

gh-116773 [https://github.com/python/cpython/issues/116773]: Fix instances of <_overlapped.Overlapped object at 0xXXX> still has pending operation at deallocation, the process may crash.

gh-91227 [https://github.com/python/cpython/issues/91227]: Fix the asyncio ProactorEventLoop implementation so that sending a datagram to an address that is not listening does not prevent receiving any more datagrams.

gh-115119 [https://github.com/python/cpython/issues/115119]: Switched from vendored libmpdecimal code to a separately-hosted external package in the cpython-source-deps repository when building the _decimal module.

C API

gh-117642 [https://github.com/python/cpython/issues/117642]: Fix PEP 737 [https://peps.python.org/pep-0737/] implementation for %#T and %#N.

gh-87193 [https://github.com/python/cpython/issues/87193]: _PyBytes_Resize() can now be called for bytes objects with reference count > 1, including 1-byte bytes objects. It creates a new bytes object and destroys the old one if it has reference count > 1.

gh-117021 [https://github.com/python/cpython/issues/117021]: Fix integer overflow in PyLong_AsPid() on non-Windows 64-bit platforms.

gh-115756 [https://github.com/python/cpython/issues/115756]: PyCode_GetFirstFree() is an ustable API now and has been renamed to PyUnstable_Code_GetFirstFree(). (Contributed by Bogdan Romanyuk in gh-115781 [https://github.com/python/cpython/issues/115781])

gh-116869 [https://github.com/python/cpython/issues/116869]: Add test_cext test: build a C extension to check if the Python C API emits C compiler warnings. Patch by Victor Stinner.

gh-116869 [https://github.com/python/cpython/issues/116869]: Make the C API compatible with -Werror=declaration-after-statement compiler flag again. Patch by Victor Stinner.

gh-116936 [https://github.com/python/cpython/issues/116936]: Add PyType_GetModuleByDef() to the limited C API. Patch by Victor Stinner.

gh-116809 [https://github.com/python/cpython/issues/116809]: Restore removed private _PyErr_ChainExceptions1() function. Patch by Victor Stinner.

gh-115754 [https://github.com/python/cpython/issues/115754]: In the limited C API version 3.13, getting Py_None, Py_False, Py_True, Py_Ellipsis and Py_NotImplemented singletons is now implemented as function calls at the stable ABI level to hide implementation details. Getting these constants still return borrowed references. Patch by Victor Stinner.

gh-115754 [https://github.com/python/cpython/issues/115754]: Add Py_GetConstant() and Py_GetConstantBorrowed() functions to get constants. For example, Py_GetConstant(Py_CONSTANT_ZERO) returns a strong reference to the constant zero. Patch by Victor Stinner.

gh-111696 [https://github.com/python/cpython/issues/111696]: Add support for %T, %T#, %N and %N# formats to PyUnicode_FromFormat(): format the fully qualified name of an object type and of a type: call PyType_GetModuleName(). See PEP 737 [https://peps.python.org/pep-0737/] for more information. Patch by Victor Stinner.

gh-111696 [https://github.com/python/cpython/issues/111696]: Add PyType_GetModuleName() function to get the type’s module name. Equivalent to getting the type.__module__ attribute. Patch by Eric Snow and Victor Stinner.

gh-111696 [https://github.com/python/cpython/issues/111696]: Add PyType_GetFullyQualifiedName() function to get the type’s fully qualified name. Equivalent to f"{type.__module__}.{type.__qualname__}", or type.__qualname__ if type.__module__ is not a string or is equal to "builtins". Patch by Victor Stinner.

gh-85283 [https://github.com/python/cpython/issues/85283]: The fcntl, grp, pwd, termios, _statistics and _testconsole C extensions are now built with the limited C API. Patch by Victor Stinner.

gh-111140 [https://github.com/python/cpython/issues/111140]: Add additional flags to PyLong_AsNativeBytes() and PyLong_FromNativeBytes() to allow the caller to determine how to handle edge cases around values that fill the entire buffer.

gh-113024 [https://github.com/python/cpython/issues/113024]: Add PyObject_GenericHash() function.

Python 3.13.0 alpha 5

Release date: 2024-03-12

Security

gh-115398 [https://github.com/python/cpython/issues/115398]: Allow controlling Expat >=2.6.0 reparse deferral (CVE 2023-52425 [https://www.cve.org/CVERecord?id=CVE-2023-52425]) by adding five new methods:

xml.etree.ElementTree.XMLParser.flush()

xml.etree.ElementTree.XMLPullParser.flush()

xml.parsers.expat.xmlparser.GetReparseDeferralEnabled()

xml.parsers.expat.xmlparser.SetReparseDeferralEnabled()

xml.sax.expatreader.ExpatParser.flush()

gh-114572 [https://github.com/python/cpython/issues/114572]: ssl.SSLContext.cert_store_stats() and ssl.SSLContext.get_ca_certs() now correctly lock access to the certificate store, when the ssl.SSLContext is shared across multiple threads.

Core and Builtins

gh-116604 [https://github.com/python/cpython/issues/116604]: Respect the status of the garbage collector when indirect calls are made via PyErr_CheckSignals() and the evaluation breaker. Patch by Pablo Galindo

gh-112087 [https://github.com/python/cpython/issues/112087]: list is now compatible with the implementation of PEP 703 [https://peps.python.org/pep-0703/].

gh-116381 [https://github.com/python/cpython/issues/116381]: Add specialization for CONTAINS_OP.

gh-116296 [https://github.com/python/cpython/issues/116296]: Fix possible refleak in object.__reduce__() internal error handling.

gh-115823 [https://github.com/python/cpython/issues/115823]: Properly calculate error ranges in the parser when raising SyntaxError exceptions caused by invalid byte sequences. Patch by Pablo Galindo

gh-115778 [https://github.com/python/cpython/issues/115778]: Add tierN annotation for instruction definition in interpreter DSL.

gh-115733 [https://github.com/python/cpython/issues/115733]: Fix crash when calling next() on exhausted list iterators.

gh-115700 [https://github.com/python/cpython/issues/115700]: The regen-cases build stage now works on Windows.

gh-115347 [https://github.com/python/cpython/issues/115347]: Fix bug where docstring was replaced by a redundant NOP when Python is run with -OO.

gh-115323 [https://github.com/python/cpython/issues/115323]: Make error message more meaningful for when bytearray.extend() is called with a str object.

gh-112175 [https://github.com/python/cpython/issues/112175]: Every PyThreadState now has its own eval_breaker, allowing specific threads to be interrupted.

gh-115154 [https://github.com/python/cpython/issues/115154]: Fix a bug that was causing the tokenize.untokenize() function to handle unicode named literals incorrectly. Patch by Pablo Galindo

gh-112433 [https://github.com/python/cpython/issues/112433]: Add ability to force alignment of ctypes.Structure by way of the new _align_ attribute on the class.

gh-104090 [https://github.com/python/cpython/issues/104090]: The multiprocessing resource tracker now exits with non-zero status code if a resource leak was detected. It still exits with status code 0 otherwise.

gh-105858 [https://github.com/python/cpython/issues/105858]: Improve the constructors for ast nodes. Arguments of list types now default to an empty list if omitted, and optional fields default to None. AST nodes now have an __annotations__ attribute with the expected types of their attributes. Passing unrecognized extra arguments to AST nodes is deprecated and will become an error in Python 3.15. Omitting a required argument to an AST node is deprecated and will become an error in Python 3.15. Patch by Jelle Zijlstra.

gh-101860 [https://github.com/python/cpython/issues/101860]: Expose __name__ attribute on property.

gh-96497 [https://github.com/python/cpython/issues/96497]: Fix incorrect resolution of mangled class variables used in assignment expressions in comprehensions.

Library

gh-116600 [https://github.com/python/cpython/issues/116600]: Fix repr() for global Flag members.

gh-116349 [https://github.com/python/cpython/issues/116349]: platform.java_ver() is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support.

gh-116143 [https://github.com/python/cpython/issues/116143]: Fix a race in pydoc _start_server, eliminating a window in which _start_server can return a thread that is “serving” but without a docserver set.

gh-116127 [https://github.com/python/cpython/issues/116127]: typing: implement PEP 705 [https://peps.python.org/pep-0705/] which adds typing.ReadOnly support to typing.TypedDict.

gh-116325 [https://github.com/python/cpython/issues/116325]: typing: raise SyntaxError instead of AttributeError on forward references as empty strings.

gh-115957 [https://github.com/python/cpython/issues/115957]: When asyncio.TaskGroup.create_task is called on an inactive asyncio.TaskGroup, the given coroutine will be closed (which prevents a RuntimeWarning).

gh-115978 [https://github.com/python/cpython/issues/115978]: Disable preadv(), readv(), pwritev(), and writev() on WASI.

Under wasmtime for WASI 0.2, these functions don’t pass test_posix (https://github.com/bytecodealliance/wasmtime/issues/7830).

gh-88352 [https://github.com/python/cpython/issues/88352]: Fix the computation of the next rollover time in the logging.TimedRotatingFileHandler handler. computeRollover() now always returns a timestamp larger than the specified time and works correctly during the DST change. doRollover() no longer overwrite the already rolled over file, saving from data loss when run at midnight or during repeated time at the DST change.

gh-87115 [https://github.com/python/cpython/issues/87115]: Set __main__.__spec__ to None when running a script with pdb

gh-76511 [https://github.com/python/cpython/issues/76511]: Fix UnicodeEncodeError in email.Message.as_string() that results when a message that claims to be in the ascii character set actually has non-ascii characters. Non-ascii characters are now replaced with the U+FFFD replacement character, like in the replace error handler.

gh-89547 [https://github.com/python/cpython/issues/89547]: Add support for nested typing special forms like Final[ClassVar[int]].

gh-65824 [https://github.com/python/cpython/issues/65824]: Improve the less prompt in pydoc.

gh-116040 [https://github.com/python/cpython/issues/116040]: [Enum] fix by-value calls when second value is falsey; e.g. Cardinal(1, 0)

gh-115821 [https://github.com/python/cpython/issues/115821]: [Enum] Improve error message when calling super().__new__() in custom __new__.

gh-85644 [https://github.com/python/cpython/issues/85644]: Use the XDG_CURRENT_DESKTOP environment variable in webbrowser to check desktop. Prefer it to the deprecated GNOME_DESKTOP_SESSION_ID for GNOME detection.

gh-75988 [https://github.com/python/cpython/issues/75988]: Fixed unittest.mock.create_autospec() to pass the call through to the wrapped object to return the real result.

gh-115881 [https://github.com/python/cpython/issues/115881]: Fix issue where ast.parse() would incorrectly flag conditional context managers (such as with (x() if y else z()): ...) as invalid syntax if feature_version=(3, 8) was passed. This reverts changes to the grammar made as part of gh-94949 [https://github.com/python/cpython/issues/94949].

gh-115886 [https://github.com/python/cpython/issues/115886]: Fix silent truncation of the name with an embedded null character in multiprocessing.shared_memory.SharedMemory.

gh-115532 [https://github.com/python/cpython/issues/115532]: Add kernel density estimation to the statistics module.

gh-115714 [https://github.com/python/cpython/issues/115714]: On WASI, the time module no longer get process time using times() or CLOCK_PROCESS_CPUTIME_ID, system API is that is unreliable and is likely to be removed from WASI. The affected clock functions fall back to calling clock().

gh-115809 [https://github.com/python/cpython/issues/115809]: Improve algorithm for computing which rolled-over log files to delete in logging.TimedRotatingFileHandler. It is now reliable for handlers without namer and with arbitrary deterministic namer that leaves the datetime part in the file name unmodified.

gh-74668 [https://github.com/python/cpython/issues/74668]: urllib.parse functions parse_qs() and parse_qsl() now support bytes arguments containing raw and percent-encoded non-ASCII data.

gh-67044 [https://github.com/python/cpython/issues/67044]: csv.writer() now always quotes or escapes '\r' and '\n', regardless of lineterminator value.

gh-115712 [https://github.com/python/cpython/issues/115712]: Restore support of space delimiter with skipinitialspace=True in csv. csv.writer() now quotes empty fields if delimiter is a space and skipinitialspace is true and raises exception if quoting is not possible.

gh-112364 [https://github.com/python/cpython/issues/112364]: Fixed ast.unparse() to handle format_spec with ", ' or \\. Patched by Frank Hoffmann.

gh-112997 [https://github.com/python/cpython/issues/112997]: Stop logging potentially sensitive callback arguments in asyncio unless debug mode is active.

gh-114914 [https://github.com/python/cpython/issues/114914]: Fix an issue where an abandoned StreamWriter would not be garbage collected.

gh-111358 [https://github.com/python/cpython/issues/111358]: Fix a bug in asyncio.BaseEventLoop.shutdown_default_executor() to ensure the timeout passed to the coroutine behaves as expected.

gh-115618 [https://github.com/python/cpython/issues/115618]: Fix improper decreasing the reference count for None argument in property methods getter(), setter() and deleter().

gh-112720 [https://github.com/python/cpython/issues/112720]: Refactor dis.ArgResolver to make it possible to subclass and change the way jump args are interpreted.

gh-112006 [https://github.com/python/cpython/issues/112006]: Fix inspect.unwrap() for types with the __wrapper__ data descriptor. Fix inspect.Signature.from_callable() for builtins classmethod() and staticmethod().

gh-101293 [https://github.com/python/cpython/issues/101293]: Support callables with the __call__() method and types with __new__() and __init__() methods set to class methods, static methods, bound methods, partial functions, and other types of methods and descriptors in inspect.Signature.from_callable().

gh-103092 [https://github.com/python/cpython/issues/103092]: Isolate _lsprof (apply PEP 687 [https://peps.python.org/pep-0687/]).

gh-113942 [https://github.com/python/cpython/issues/113942]: pydoc no longer skips global functions implemented as builtin methods, such as MethodDescriptorType and WrapperDescriptorType.

gh-115256 [https://github.com/python/cpython/issues/115256]: Added DeprecationWarning when accessing the tarfile attribute of TarInfo objects. The attribute is never used internally and is only attached to TarInfos when the tarfile is opened in write-mode, not read-mode. The attribute creates an unnecessary reference cycle which may cause corruption when not closing the handle after writing a tarfile.

gh-115197 [https://github.com/python/cpython/issues/115197]: urllib.request no longer resolves the hostname before checking it against the system’s proxy bypass list on macOS and Windows.

gh-113812 [https://github.com/python/cpython/issues/113812]: DatagramTransport.sendto() will now send zero-length datagrams if called with an empty bytes object. The transport flow control also now accounts for the datagram header when calculating the buffer size.

gh-114763 [https://github.com/python/cpython/issues/114763]: Protect modules loaded with importlib.util.LazyLoader from race conditions when multiple threads try to access attributes before the loading is complete.

gh-114709 [https://github.com/python/cpython/issues/114709]: posixpath.commonpath() now raises a ValueError exception when passed an empty iterable. Previously, IndexError was raised.

posixpath.commonpath() now raises a TypeError exception when passed None. Previously, ValueError was raised.

gh-114610 [https://github.com/python/cpython/issues/114610]: Fix bug where pathlib.PurePath.with_stem() converted a non-empty path suffix to a stem when given an empty stem argument. It now raises ValueError, just like pathlib.PurePath.with_suffix() does when called on a path with an empty stem, given a non-empty suffix argument.

gh-107361 [https://github.com/python/cpython/issues/107361]: Add ssl.VERIFY_X509_PARTIAL_CHAIN and VERIFY_X509_STRICT to the default SSL context created with ssl.create_default_context().

gh-112281 [https://github.com/python/cpython/issues/112281]: Allow creating union of types for typing.Annotated with unhashable metadata.

gh-111775 [https://github.com/python/cpython/issues/111775]: Fix importlib.resources.simple.ResourceHandle.open() for text mode, added missed stream argument.

gh-90095 [https://github.com/python/cpython/issues/90095]: Make .pdbrc and -c work with any valid pdb commands.

gh-107625 [https://github.com/python/cpython/issues/107625]: Raise configparser.ParsingError from read() and read_file() methods of configparser.ConfigParser if a key without a corresponding value is continued (that is, followed by an indented line).

gh-107155 [https://github.com/python/cpython/issues/107155]: Fix incorrect output of help(x) where x is a lambda function, which has an __annotations__ dictionary attribute with a "return" key.

gh-57141 [https://github.com/python/cpython/issues/57141]: Add option for non-shallow comparisons to filecmp.dircmp like filecmp.cmp(). Original patch by Steven Ward. Enhanced by Tobias Rautenkranz

gh-69990 [https://github.com/python/cpython/issues/69990]: Profile.print_stats() has been improved to accept multiple sort arguments. Patched by Chiu-Hsiang Hsu and Furkan Onder.

gh-104061 [https://github.com/python/cpython/issues/104061]: Add socket.SO_BINDTOIFINDEX constant.

gh-60346 [https://github.com/python/cpython/issues/60346]: Fix ArgumentParser inconsistent with parse_known_args.

gh-102389 [https://github.com/python/cpython/issues/102389]: Add windows_31j to aliases for cp932 codec

gh-72249 [https://github.com/python/cpython/issues/72249]: functools.partial`s of :func:`repr() has been improved to include the module name. Patched by Furkan Onder and Anilyka Barry.

gh-100985 [https://github.com/python/cpython/issues/100985]: Update HTTPSConnection to consistently wrap IPv6 Addresses when using a proxy.

gh-100884 [https://github.com/python/cpython/issues/100884]: email: fix misfolding of comma in address-lists over multiple lines in combination with unicode encoding.

gh-95782 [https://github.com/python/cpython/issues/95782]: Fix io.BufferedReader.tell(), io.BufferedReader.seek(), _pyio.BufferedReader.tell(), io.BufferedRandom.tell(), io.BufferedRandom.seek() and _pyio.BufferedRandom.tell() being able to return negative offsets.

gh-96310 [https://github.com/python/cpython/issues/96310]: Fix a traceback in argparse when all options in a mutually exclusive group are suppressed.

gh-93205 [https://github.com/python/cpython/issues/93205]: Fixed a bug in logging.handlers.TimedRotatingFileHandler where multiple rotating handler instances pointing to files with the same name but different extensions would conflict and not delete the correct files.

bpo-31116 [https://bugs.python.org/issue?@action=redirect&bpo=31116]: Add Z85 encoding to base64.

bpo-44865 [https://bugs.python.org/issue?@action=redirect&bpo=44865]: Add missing call to localization function in argparse.

bpo-43952 [https://bugs.python.org/issue?@action=redirect&bpo=43952]: Fix multiprocessing.connection.Listener.accept() to accept empty bytes as authkey. Not accepting empty bytes as key causes it to hang indefinitely.

bpo-42125 [https://bugs.python.org/issue?@action=redirect&bpo=42125]: linecache: get module name from __spec__ if available. This allows getting source code for the __main__ module when a custom loader is used.

bpo-41122 [https://bugs.python.org/issue?@action=redirect&bpo=41122]: Failing to pass arguments properly to functools.singledispatchmethod() now throws a TypeError instead of hitting an index out of bounds internally.

bpo-40818 [https://bugs.python.org/issue?@action=redirect&bpo=40818]: The asyncio REPL now runs sys.__interactivehook__ on startup. The default implementation of sys.__interactivehook__ provides auto-completion to the asyncio REPL. Patch contributed by Rémi Lapeyre.

bpo-33775 [https://bugs.python.org/issue?@action=redirect&bpo=33775]: Add ‘default’ and ‘version’ help text for localization in argparse.

Documentation

gh-115399 [https://github.com/python/cpython/issues/115399]: Document CVE 2023-52425 [https://www.cve.org/CVERecord?id=CVE-2023-52425] of Expat <2.6.0 under “XML vulnerabilities”.

gh-109653 [https://github.com/python/cpython/issues/109653]: Improve import time of uuid on Linux.

Tests

gh-71052 [https://github.com/python/cpython/issues/71052]: Add test exclusions to support running the test suite on Android.

gh-71052 [https://github.com/python/cpython/issues/71052]: Enable test_concurrent_futures on platforms that support threading but not multiprocessing.

gh-115796 [https://github.com/python/cpython/issues/115796]: Make ‘_testinternalcapi.assemble_code_object’ construct the exception table for the code object.

gh-115720 [https://github.com/python/cpython/issues/115720]: Leak tests (-R, --huntrleaks) now show a summary of the number of leaks found in each iteration.

gh-115122 [https://github.com/python/cpython/issues/115122]: Add --bisect option to regrtest test runner: run failed tests with test.bisect_cmd to identify failing tests. Patch by Victor Stinner.

gh-115596 [https://github.com/python/cpython/issues/115596]: Fix ProgramPriorityTests in test_os permanently changing the process priority.

gh-115556 [https://github.com/python/cpython/issues/115556]: On Windows, commas passed in arguments to Tools\buildbot\test.bat and PCbuild\\rt.bat are now properly handled.

gh-115420 [https://github.com/python/cpython/issues/115420]: Fix translation of exception handler targets by _testinternalcapi.optimize_cfg.

gh-115376 [https://github.com/python/cpython/issues/115376]: Fix segfault in _testinternalcapi.compiler_codegen on bad input.

Build

gh-116313 [https://github.com/python/cpython/issues/116313]: Get WASI builds to work under wasmtime 18 w/ WASI 0.2/preview2 primitives.

gh-71052 [https://github.com/python/cpython/issues/71052]: Change Android’s sys.platform from "linux" to "android".

gh-116117 [https://github.com/python/cpython/issues/116117]: Backport libb2’s PR #42 to fix compiling CPython on 32-bit Windows with clang-cl.

gh-71052 [https://github.com/python/cpython/issues/71052]: Fix several Android build issues

gh-114099 [https://github.com/python/cpython/issues/114099]: A testbed project was added to run the test suite on iOS.

gh-115350 [https://github.com/python/cpython/issues/115350]: Fix building ctypes module with -DWIN32_LEAN_AND_MEAN defined

gh-111225 [https://github.com/python/cpython/issues/111225]: Link extension modules against libpython on Android.

gh-115737 [https://github.com/python/cpython/issues/115737]: The install name for libPython is now correctly set for non-framework macOS builds.

gh-114099 [https://github.com/python/cpython/issues/114099]: Makefile targets were added to support compiling an iOS-compatible framework build.

Windows

gh-116012 [https://github.com/python/cpython/issues/116012]: Ensure the value of GetLastError() is preserved across GIL operations.

gh-115582 [https://github.com/python/cpython/issues/115582]: Building extensions intended for free-threaded builds of CPython now require compiling with /DPy_GIL_DISABLED manually when using a regular install. This is expected to change in future releases.

gh-115554 [https://github.com/python/cpython/issues/115554]: The installer now has more strict rules about updating the 윈도우 용 파이썬 런처. In general, most users only have a single launcher installed and will see no difference. When multiple launchers have been installed, the option to install the launcher is disabled until all but one have been removed. Downgrading the launcher (which was never allowed) is now more obviously blocked.

gh-115543 [https://github.com/python/cpython/issues/115543]: 윈도우 용 파이썬 런처 can now detect Python 3.13 when installed from the Microsoft Store, and will install Python 3.12 by default when PYLAUNCHER_ALLOW_INSTALL is set.

macOS

gh-116145 [https://github.com/python/cpython/issues/116145]: Update macOS installer to Tcl/Tk 8.6.14.

IDLE

gh-88516 [https://github.com/python/cpython/issues/88516]: On macOS show a proxy icon in the title bar of editor windows to match platform behaviour.

Tools/Demos

gh-100176 [https://github.com/python/cpython/issues/100176]: Remove outdated Tools/{io,cc,string}bench

bpo-45101 [https://bugs.python.org/issue?@action=redirect&bpo=45101]: Add consistency in usage message IO between 2 versions of python-config.

C API

gh-114626 [https://github.com/python/cpython/issues/114626]: Add again _PyCFunctionFastWithKeywords name, removed in Python 3.13 alpha 4 by mistake. Keep the old private _PyCFunctionFastWithKeywords name (Python 3.7) as an alias to the new public name PyCFunctionFastWithKeywords (Python 3.13a4). Patch by Victor Stinner.

gh-111418 [https://github.com/python/cpython/issues/111418]: Add PyHASH_MODULUS, PyHASH_BITS, PyHASH_INF and PyHASH_IMAG C macros. Patch by Sergey B Kirpichev.

Python 3.13.0 alpha 4

Release date: 2024-02-15

Security

gh-115399 [https://github.com/python/cpython/issues/115399]: Update bundled libexpat to 2.6.0

gh-115243 [https://github.com/python/cpython/issues/115243]: Fix possible crashes in collections.deque.index() when the deque is concurrently modified.

Core and Builtins

gh-112087 [https://github.com/python/cpython/issues/112087]: For an empty reverse iterator for list will be reduced to reversed(). Patch by Donghee Na

gh-114570 [https://github.com/python/cpython/issues/114570]: Add PythonFinalizationError exception. This exception derived from RuntimeError is raised when an operation is blocked during the Python finalization. Patch by Victor Stinner.

gh-114695 [https://github.com/python/cpython/issues/114695]: Add sys._clear_internal_caches(), which clears all internal performance-related caches (and deprecate the less-general sys._clear_type_cache() function).

gh-114828 [https://github.com/python/cpython/issues/114828]: Fix compilation crashes in uncommon code examples using super() inside a comprehension in a class body.

gh-112069 [https://github.com/python/cpython/issues/112069]: Adapt set and frozenset methods to Argument Clinic.

gh-115011 [https://github.com/python/cpython/issues/115011]: Setters for members with an unsigned integer type now support the same range of valid values for objects that has a __index__() method as for int.

gh-114887 [https://github.com/python/cpython/issues/114887]: Changed socket type validation in create_datagram_endpoint() to accept all non-stream sockets. This fixes a regression in compatibility with raw sockets.

gh-114944 [https://github.com/python/cpython/issues/114944]: Fixes a race between PyParkingLot_Park and _PyParkingLot_UnparkAll.

gh-113462 [https://github.com/python/cpython/issues/113462]: Limit the number of versions that a single class can use. Prevents a few wayward classes using up all the version numbers.

gh-76763 [https://github.com/python/cpython/issues/76763]: The chr() builtin function now always raises ValueError for values outside the valid range. Previously it raised OverflowError for very large or small values.

gh-114806 [https://github.com/python/cpython/issues/114806]: No longer specialize calls to classes, if those classes have metaclasses. Fixes bug where the __call__ method of the metaclass was not being called.

gh-107944 [https://github.com/python/cpython/issues/107944]: Improve error message for function calls with bad keyword arguments via getargs

gh-112529 [https://github.com/python/cpython/issues/112529]: The free-threaded build no longer allocates space for the PyGC_Head structure in objects that support cyclic garbage collection. A number of other fields and data structures are used as replacements, including ob_gc_bits, ob_tid, and mimalloc internal data structures.

gh-114456 [https://github.com/python/cpython/issues/114456]: Lower the recursion limit under a debug build of WASI.

gh-114083 [https://github.com/python/cpython/issues/114083]: Compiler applies folding of LOAD_CONST with following instruction in a separate pass before other optimisations. This enables jump threading in certain circumstances.

gh-114388 [https://github.com/python/cpython/issues/114388]: Fix a RuntimeWarning emitted when assign an integer-like value that is not an instance of int to an attribute that corresponds to a C struct member of type T_UINT and T_ULONG. Fix a double RuntimeWarning emitted when assign a negative integer value to an attribute that corresponds to a C struct member of type T_UINT.

gh-114265 [https://github.com/python/cpython/issues/114265]: Compiler propagates line numbers before optimization, leading to more optimization opportunities and removing the need for the guarantee_lineno_for_exits hack.

gh-112529 [https://github.com/python/cpython/issues/112529]: The free-threaded build now has its own thread-safe GC implementation that uses mimalloc to find GC tracked objects. It is non-generational, unlike the existing GC implementation.

gh-114050 [https://github.com/python/cpython/issues/114050]: Fix segmentation fault caused by an incorrect format string in TypeError exception when more than two arguments are passed to int.

gh-112354 [https://github.com/python/cpython/issues/112354]: The END_FOR instruction now pops only one value. This is to better support side exits in loops.

gh-113884 [https://github.com/python/cpython/issues/113884]: Make queue.SimpleQueue thread safe when the GIL is disabled.

gh-114058 [https://github.com/python/cpython/issues/114058]: Implement the foundations of the Tier 2 redundancy eliminator.

gh-113939 [https://github.com/python/cpython/issues/113939]: frame.clear(): Clear frame.f_locals as well, and not only the fast locals. This is relevant once frame.f_locals was accessed, which would contain also references to all the locals.

gh-112050 [https://github.com/python/cpython/issues/112050]: Convert collections.deque to use Argument Clinic.

gh-112050 [https://github.com/python/cpython/issues/112050]: Make methods on collections.deque thread-safe when the GIL is disabled.

gh-113464 [https://github.com/python/cpython/issues/113464]: Add an option (--enable-experimental-jit for configure-based builds or --experimental-jit for PCbuild-based ones) to build an experimental just-in-time compiler, based on copy-and-patch [https://fredrikbk.com/publications/copy-and-patch.pdf]

gh-113055 [https://github.com/python/cpython/issues/113055]: Make interp->obmalloc a pointer. For interpreters that share state with the main interpreter, this points to the same static memory structure. For interpreters with their own obmalloc state, it is heap allocated. Add free_obmalloc_arenas() which will free the obmalloc arenas and radix tree structures for interpreters with their own obmalloc state.

gh-55664 [https://github.com/python/cpython/issues/55664]: Add warning when creating type using a namespace dictionary with non-string keys. Patched by Daniel Urban and Furkan Onder.

gh-104530 [https://github.com/python/cpython/issues/104530]: Use native Win32 condition variables.

Library

gh-115392 [https://github.com/python/cpython/issues/115392]: Fix a bug in doctest where incorrect line numbers would be reported for decorated functions.

gh-114563 [https://github.com/python/cpython/issues/114563]: Fix several format() bugs when using the C implementation of Decimal: * memory leak in some rare cases when using the z format option (coerce negative 0) * incorrect output when applying the z format option to type F (fixed-point with capital NAN / INF) * incorrect output when applying the # format option (alternate form)

gh-102840 [https://github.com/python/cpython/issues/102840]: Fix confused traceback when floordiv, mod, or divmod operations happens between instances of fractions.Fraction and complex.

gh-115165 [https://github.com/python/cpython/issues/115165]: Most exceptions are now ignored when attempting to set the __orig_class__ attribute on objects returned when calling typing generic aliases (including generic aliases created using typing.Annotated). Previously only AttributeError was ignored. Patch by Dave Shawley.

gh-112903 [https://github.com/python/cpython/issues/112903]: Fix “issubclass() arg 1 must be a class” errors in certain cases of multiple inheritance with generic aliases (regression in early 3.13 alpha releases).

gh-115133 [https://github.com/python/cpython/issues/115133]: Fix tests for XMLPullParser with Expat 2.6.0.

gh-115059 [https://github.com/python/cpython/issues/115059]: io.BufferedRandom.read1() now flushes the underlying write buffer.

gh-79382 [https://github.com/python/cpython/issues/79382]: Trailing ** no longer allows to match files and non-existing paths in recursive glob().

gh-67837 [https://github.com/python/cpython/issues/67837]: Avoid race conditions in the creation of directories during concurrent extraction in tarfile and zipfile.

gh-115060 [https://github.com/python/cpython/issues/115060]: Speed up pathlib.Path.glob() by removing redundant regex matching.

gh-97928 [https://github.com/python/cpython/issues/97928]: Partially revert the behavior of tkinter.Text.count(). By default it preserves the behavior of older Python versions, except that setting wantobjects to 0 no longer has effect. Add a new parameter return_ints: specifying return_ints=True makes Text.count() always returning the single count as an integer instead of a 1-tuple or None.

gh-114628 [https://github.com/python/cpython/issues/114628]: When csv.Error is raised when handling TypeError, do not print the TypeError traceback.

gh-85984 [https://github.com/python/cpython/issues/85984]: Added _POSIX_VDISABLE from C’s <unistd.h> to termios.

gh-114965 [https://github.com/python/cpython/issues/114965]: Update bundled pip to 24.0

gh-114959 [https://github.com/python/cpython/issues/114959]: tarfile no longer ignores errors when trying to extract a directory on top of a file.

gh-114894 [https://github.com/python/cpython/issues/114894]: Add array.array.clear().

gh-114071 [https://github.com/python/cpython/issues/114071]: Support tuple subclasses using auto() for enum member value.

gh-109475 [https://github.com/python/cpython/issues/109475]: Fix support of explicit option value “–” in argparse (e.g. --option=--).

gh-49766 [https://github.com/python/cpython/issues/49766]: Fix date-datetime comparison. Now the special comparison methods like __eq__ and __lt__ return NotImplemented if one of comparands is date and other is datetime instead of ignoring the time part and the time zone or forcefully return “not equal” or raise TypeError. It makes comparison of date and datetime subclasses more symmetric and allows to change the default behavior by overriding the special comparison methods in subclasses.

gh-110190 [https://github.com/python/cpython/issues/110190]: Fix ctypes structs with array on Windows ARM64 platform by setting MAX_STRUCT_SIZE to 32 in stgdict. Patch by Diego Russo

gh-114678 [https://github.com/python/cpython/issues/114678]: Ensure that deprecation warning for ‘N’ specifier in Decimal format is not raised for cases where ‘N’ appears in other places in the format specifier. Based on patch by Stefan Krah.

gh-70303 [https://github.com/python/cpython/issues/70303]: Return both files and directories from pathlib.Path.glob() if a pattern ends with “**”. Previously only directories were returned.

gh-109653 [https://github.com/python/cpython/issues/109653]: Improve import time of importlib.metadata and email.utils.

gh-113280 [https://github.com/python/cpython/issues/113280]: Fix a leak of open socket in rare cases when error occurred in ssl.SSLSocket creation.

gh-77749 [https://github.com/python/cpython/issues/77749]: email.policy.EmailPolicy.fold() now always encodes non-ASCII characters in headers if utf8 is false.

gh-83383 [https://github.com/python/cpython/issues/83383]: Synchronization of the dbm.dumb database is now no-op if there was no modification since opening or last synchronization. The directory file for a newly created empty dbm.dumb database is now created immediately after opening instead of deferring this until synchronizing or closing.

gh-91602 [https://github.com/python/cpython/issues/91602]: Add filter keyword-only parameter to sqlite3.Connection.iterdump() for filtering database objects to dump. Patch by Mariusz Felisiak.

gh-112451 [https://github.com/python/cpython/issues/112451]: Prohibit subclassing pure-Python datetime.timezone. This is consistent with C-extension implementation. Patch by Mariusz Felisiak.

gh-69893 [https://github.com/python/cpython/issues/69893]: Add the close() method for the iterator returned by xml.etree.ElementTree.iterparse().

gh-109653 [https://github.com/python/cpython/issues/109653]: Reduce the import time of threading module by ~50%. Patch by Daniel Hollas.

gh-114492 [https://github.com/python/cpython/issues/114492]: Make the result of termios.tcgetattr() reproducible on Alpine Linux. Previously it could leave a random garbage in some fields.

gh-114315 [https://github.com/python/cpython/issues/114315]: Make threading.Lock a real class, not a factory function. Add __new__ to _thread.lock type.

gh-100414 [https://github.com/python/cpython/issues/100414]: Add dbm.sqlite3 as a backend to dbm, and make it the new default dbm backend. Patch by Raymond Hettinger and Erlend E. Aasland.

gh-113267 [https://github.com/python/cpython/issues/113267]: Revert changes in gh-106584 [https://github.com/python/cpython/issues/106584] which made calls of TestResult methods startTest() and stopTest() unbalanced.

gh-75128 [https://github.com/python/cpython/issues/75128]: Ignore an OSError in asyncio.BaseEventLoop.create_server() when IPv6 is available but the interface cannot actually support it.

gh-114423 [https://github.com/python/cpython/issues/114423]: _DummyThread entries in threading._active are now automatically removed when the related thread dies.

gh-114257 [https://github.com/python/cpython/issues/114257]: Dismiss the FileNotFound error in ctypes.util.find_library() and just return None on Linux.

gh-114321 [https://github.com/python/cpython/issues/114321]: Expose more platform specific constants in the fcntl module on Linux, macOS, FreeBSD and NetBSD.

gh-114328 [https://github.com/python/cpython/issues/114328]: The tty.setcbreak() and new tty.cfmakecbreak() no longer clears the terminal input ICRLF flag. This fixes a regression introduced in 3.12 that no longer matched how OSes define cbreak mode in their stty(1) manual pages.

gh-114281 [https://github.com/python/cpython/issues/114281]: Remove type hints from Lib/asyncio/staggered.py. The annotations in the typeshed [https://github.com/python/typeshed] project should be used instead.

gh-101438 [https://github.com/python/cpython/issues/101438]: Avoid reference cycle in ElementTree.iterparse. The iterator returned by ElementTree.iterparse may hold on to a file descriptor. The reference cycle prevented prompt clean-up of the file descriptor if the returned iterator was not exhausted.

gh-114198 [https://github.com/python/cpython/issues/114198]: The signature for the __replace__ method on dataclasses now has the first argument named self, rather than obj.

gh-104522 [https://github.com/python/cpython/issues/104522]: OSError raised when run a subprocess now only has filename attribute set to cwd if the error was caused by a failed attempt to change the current directory.

gh-114149 [https://github.com/python/cpython/issues/114149]: Enum: correctly handle tuple subclasses in custom __new__.

gh-83648 [https://github.com/python/cpython/issues/83648]: Support deprecation of options, positional arguments and subcommands in argparse.

gh-114087 [https://github.com/python/cpython/issues/114087]: Speed up dataclasses.asdict up to 1.35x.

gh-109534 [https://github.com/python/cpython/issues/109534]: Fix a reference leak in asyncio.selector_events.BaseSelectorEventLoop when SSL handshakes fail. Patch contributed by Jamie Phan.

gh-79634 [https://github.com/python/cpython/issues/79634]: Accept path-like objects as patterns in pathlib.Path.glob() and rglob().

gh-112202 [https://github.com/python/cpython/issues/112202]: Ensure that a asyncio.Condition.notify() call does not get lost if the awakened Task is simultaneously cancelled or encounters any other error.

gh-113951 [https://github.com/python/cpython/issues/113951]: Fix the behavior of tag_unbind() methods of tkinter.Text and tkinter.Canvas classes with three arguments. Previously, widget.tag_unbind(tag, sequence, funcid) destroyed the current binding for sequence, leaving sequence unbound, and deleted the funcid command. Now it removes only funcid from the binding for sequence, keeping other commands, and deletes the funcid command. It leaves sequence unbound only if funcid was the last bound command.

gh-97959 [https://github.com/python/cpython/issues/97959]: Fix rendering class methods, bound methods, method and function aliases in pydoc. Class methods no longer have “method of builtins.type instance” note. Corresponding notes are now added for class and unbound methods. Method and function aliases now have references to the module or the class where the origin was defined if it differs from the current. Bound methods are now listed in the static methods section. Methods of builtin classes are now supported as well as methods of Python classes.

gh-113796 [https://github.com/python/cpython/issues/113796]: Add more validation checks in the csv.Dialect constructor. ValueError is now raised if the same character is used in different roles.

gh-113732 [https://github.com/python/cpython/issues/113732]: Fix support of QUOTE_NOTNULL and QUOTE_STRINGS in csv.reader().

gh-113225 [https://github.com/python/cpython/issues/113225]: Speed up pathlib.Path.walk() by using os.DirEntry.path where possible.

gh-89039 [https://github.com/python/cpython/issues/89039]: When replace() method is called on a subclass of datetime, date or time, properly call derived constructor. Previously, only the base class’s constructor was called.

Also, make sure to pass non-zero fold values when creating subclasses in various methods. Previously, fold was silently ignored.

gh-112919 [https://github.com/python/cpython/issues/112919]: Speed-up datetime.datetime.replace(), datetime.date.replace() and datetime.time.replace().

gh-59013 [https://github.com/python/cpython/issues/59013]: Set breakpoint on the first executable line of the function, instead of the line of function definition when the user do break func using pdb

gh-112343 [https://github.com/python/cpython/issues/112343]: Improve handling of pdb convenience variables to avoid replacing string contents.

gh-112240 [https://github.com/python/cpython/issues/112240]: Add option to calendar module CLI to specify the weekday to start each week. Patch by Steven Ward.

gh-111741 [https://github.com/python/cpython/issues/111741]: Recognise image/webp as a standard format in the mimetypes module.

gh-43457 [https://github.com/python/cpython/issues/43457]: Fix the tkinter widget method wm_attributes(). It now accepts the attribute name without the minus prefix to get window attributes and allows to specify attributes and values to set as keyword arguments. Add new optional keyword argument return_python_dict: calling w.wm_attributes(return_python_dict=True) returns the attributes as a dict instead of a tuple. Calling w.wm_attributes() now returns a tuple instead of string if wantobjects was set to 0.

gh-82626 [https://github.com/python/cpython/issues/82626]: Many functions now emit a warning if a boolean value is passed as a file descriptor argument.

gh-111051 [https://github.com/python/cpython/issues/111051]: Added check for file modification during debugging with pdb

gh-110345 [https://github.com/python/cpython/issues/110345]: Show the Tcl/Tk patchlevel (rather than version) in tkinter._test().

gh-38807 [https://github.com/python/cpython/issues/38807]: Fix race condition in trace. Instead of checking if a directory exists and creating it, directly call os.makedirs() with the kwarg exist_ok=True.

gh-75705 [https://github.com/python/cpython/issues/75705]: Set unixfrom envelope in mailbox.mbox and mailbox.MMDF.

gh-106233 [https://github.com/python/cpython/issues/106233]: Fix stacklevel in InvalidTZPathWarning during zoneinfo module import.

gh-105102 [https://github.com/python/cpython/issues/105102]: Allow ctypes.Union to be nested in ctypes.Structure when the system endianness is the opposite of the classes.

gh-104282 [https://github.com/python/cpython/issues/104282]: Fix null pointer dereference in lzma._decode_filter_properties() due to improper handling of BCJ filters with properties of zero length. Patch by Radislav Chugunov.

gh-96471 [https://github.com/python/cpython/issues/96471]: Add queue.Queue termination with shutdown().

gh-101599 [https://github.com/python/cpython/issues/101599]: Changed argparse flag options formatting to remove redundancy.

gh-85984 [https://github.com/python/cpython/issues/85984]: Add POSIX pseudo-terminal functions os.posix_openpt(), os.grantpt(), os.unlockpt(), and os.ptsname().

gh-102512 [https://github.com/python/cpython/issues/102512]: When os.fork() is called from a foreign thread (aka _DummyThread), the type of the thread in a child process is changed to _MainThread. Also changed its name and daemonic status, it can be now joined.

gh-88569 [https://github.com/python/cpython/issues/88569]: Add os.path.isreserved(), which identifies reserved pathnames such as “NUL”, “AUX” and “CON”. This function is only available on Windows.

Deprecate pathlib.PurePath.is_reserved().

bpo-38364 [https://bugs.python.org/issue?@action=redirect&bpo=38364]: The inspect functions isgeneratorfunction, iscoroutinefunction, isasyncgenfunction now support functools.partialmethod wrapped functions the same way they support functools.partial.

Documentation

gh-115233 [https://github.com/python/cpython/issues/115233]: Fix an example for LoggerAdapter in the Logging Cookbook.

gh-114123 [https://github.com/python/cpython/issues/114123]: Move the csv module docstring to the csv module instead of reexporting it from the internal _csv module, and remove __doc__ from csv.__all__.

Move csv.__version__ to the csv module instead of reexporting it from the internal _csv module, and remove __version__ from csv.__all__.

Tests

gh-114099 [https://github.com/python/cpython/issues/114099]: Added test exclusions required to run the test suite on iOS.

gh-105089 [https://github.com/python/cpython/issues/105089]: Fix test.test_zipfile.test_core.TestWithDirectory.test_create_directory_with_write test in AIX by doing a bitwise AND of 0xFFFF on mode , so that it will be in sync with zinfo.external_attr

Build

gh-115167 [https://github.com/python/cpython/issues/115167]: Avoid vendoring vcruntime140_threads.dll when building with Visual Studio 2022 version 17.8.

gh-113632 [https://github.com/python/cpython/issues/113632]: Promote WASI to a tier 2 platform and drop Emscripten from tier 3 in configure.ac.

gh-114099 [https://github.com/python/cpython/issues/114099]: configure and Makefile were refactored to accommodate framework builds on Apple platforms other than macOS.

gh-114875 [https://github.com/python/cpython/issues/114875]: Add getgrent() as a prerequisite for building the grp module.

Windows

gh-115049 [https://github.com/python/cpython/issues/115049]: Fixes py.exe launcher failing when run as users without user profiles.

gh-115009 [https://github.com/python/cpython/issues/115009]: Update Windows installer to use SQLite 3.45.1.

gh-109991 [https://github.com/python/cpython/issues/109991]: Update Windows build to use OpenSSL 3.0.13.

gh-111239 [https://github.com/python/cpython/issues/111239]: Update Windows builds to use zlib v1.3.1.

gh-100107 [https://github.com/python/cpython/issues/100107]: The py.exe launcher will no longer attempt to run the Microsoft Store redirector when launching a script containing a /usr/bin/env shebang

gh-112984 [https://github.com/python/cpython/issues/112984]: Adds free-threaded binaries to Windows installer as an optional component.

gh-89240 [https://github.com/python/cpython/issues/89240]: Allows multiprocessing to create pools of greater than 62 processes.

macOS

gh-115009 [https://github.com/python/cpython/issues/115009]: Update macOS installer to use SQLite 3.45.1.

gh-109991 [https://github.com/python/cpython/issues/109991]: Update macOS installer to use OpenSSL 3.0.13.

gh-114490 [https://github.com/python/cpython/issues/114490]: Add Mach-O linkage support for platform.architecture().

gh-87804 [https://github.com/python/cpython/issues/87804]: On macOS the result of os.statvfs and os.fstatvfs now correctly report the size of very large disks, in previous versions the reported number of blocks was wrong for disks with at least 2**32 blocks.

IDLE

gh-96905 [https://github.com/python/cpython/issues/96905]: In idlelib code, stop redefining built-ins ‘dict’ and ‘object’.

gh-103820 [https://github.com/python/cpython/issues/103820]: Revise IDLE bindings so that events from mouse button 4/5 on non-X11 windowing systems (i.e. Win32 and Aqua) are not mistaken for scrolling.

Tools/Demos

gh-113516 [https://github.com/python/cpython/issues/113516]: Don’t set LDSHARED when building for WASI.

gh-109991 [https://github.com/python/cpython/issues/109991]: Update GitHub CI workflows to use OpenSSL 3.0.13 and multissltests to use 1.1.1w, 3.0.13, 3.1.5, and 3.2.1.

gh-115015 [https://github.com/python/cpython/issues/115015]: Fix a bug in Argument Clinic that generated incorrect code for methods with no parameters that use the METH_METHOD | METH_FASTCALL | METH_KEYWORDS calling convention. Only the positional parameter count was checked; any keyword argument passed would be silently accepted.

C API

gh-111140 [https://github.com/python/cpython/issues/111140]: Adds PyLong_AsNativeBytes(), PyLong_FromNativeBytes() and PyLong_FromUnsignedNativeBytes() functions.

gh-114685 [https://github.com/python/cpython/issues/114685]: PyBuffer_FillInfo() now raises a SystemError if called with PyBUF_READ or PyBUF_WRITE as flags. These flags should only be used with the PyMemoryView_* C API.

gh-114685 [https://github.com/python/cpython/issues/114685]: PyObject_GetBuffer() now raises a SystemError if called with PyBUF_READ or PyBUF_WRITE as flags. These flags should only be used with the PyMemoryView_* C API.

gh-114626 [https://github.com/python/cpython/issues/114626]: Add PyCFunctionFast and PyCFunctionFastWithKeywords typedefs (identical to the existing _PyCFunctionFast and _PyCFunctionFastWithKeywords typedefs, just without a leading _ prefix).

gh-114329 [https://github.com/python/cpython/issues/114329]: Add PyList_GetItemRef(), which is similar to PyList_GetItem() but returns a strong reference instead of a borrowed reference.

gh-110850 [https://github.com/python/cpython/issues/110850]: Add PyTime C API:

PyTime_t type.

PyTime_MIN and PyTime_MAX constants.

PyTime_AsSecondsDouble(), PyTime_Monotonic(), PyTime_PerfCounter(), and PyTime_Time() functions.

Patch by Victor Stinner.

gh-112066 [https://github.com/python/cpython/issues/112066]: Add PyDict_SetDefaultRef(): insert a key and value into a dictionary if the key is not already present. This is similar to dict.setdefault(), but returns an integer value indicating if the key was already present. It is also similar to PyDict_SetDefault(), but returns a strong reference instead of a borrowed reference.

Python 3.13.0 alpha 3

Release date: 2024-01-17

Security

gh-113659 [https://github.com/python/cpython/issues/113659]: Skip .pth files with names starting with a dot or hidden file attribute.

gh-112302 [https://github.com/python/cpython/issues/112302]: Created a Software Bill-of-Materials document and tooling for tracking dependencies.

Core and Builtins

gh-107901 [https://github.com/python/cpython/issues/107901]: Compiler duplicates basic blocks that have an eval breaker check, no line number, and multiple predecessors.

gh-107901 [https://github.com/python/cpython/issues/107901]: A jump leaving an exception handler back to normal code no longer checks the eval breaker.

gh-113655 [https://github.com/python/cpython/issues/113655]: Set the C recursion limit to 4000 on Windows, and 10000 on Linux/OSX. This seems to be near the sweet spot to maintain safety, but not compromise backwards compatibility.

gh-113710 [https://github.com/python/cpython/issues/113710]: Add typed stack effects to the interpreter DSL, along with various instruction annotations.

gh-77046 [https://github.com/python/cpython/issues/77046]: On Windows, file descriptors wrapping Windows handles are now created non inheritable by default (PEP 446 [https://peps.python.org/pep-0446/]). Patch by Zackery Spytz and Victor Stinner.

gh-113853 [https://github.com/python/cpython/issues/113853]: Guarantee that all executors make progress. This then guarantees that tier 2 execution always makes progress.

gh-113753 [https://github.com/python/cpython/issues/113753]: Fix an issue where the finalizer of PyAsyncGenASend objects might not be called if they were allocated from a free list.

gh-107901 [https://github.com/python/cpython/issues/107901]: Compiler changed so that synthetic jumps which are not at loop end no longer check the eval breaker.

gh-113703 [https://github.com/python/cpython/issues/113703]: Fix a regression in the codeop module that was causing it to incorrectly identify incomplete f-strings. Patch by Pablo Galindo

gh-89811 [https://github.com/python/cpython/issues/89811]: Check for a valid tp_version_tag before performing bytecode specializations that rely on this value being usable.

gh-111488 [https://github.com/python/cpython/issues/111488]: Changed error message in case of no ‘in’ keyword after ‘for’ in list comprehensions

gh-113657 [https://github.com/python/cpython/issues/113657]: Fix an issue that caused important instruction pointer updates to be optimized out of tier two traces.

gh-113603 [https://github.com/python/cpython/issues/113603]: Fixed bug where a redundant NOP is not removed, causing an assertion to fail in the compiler in debug mode.

gh-113602 [https://github.com/python/cpython/issues/113602]: Fix an error that was causing the parser to try to overwrite existing errors and crashing in the process. Patch by Pablo Galindo

gh-113486 [https://github.com/python/cpython/issues/113486]: No longer issue spurious PY_UNWIND events for optimized calls to classes.

gh-113297 [https://github.com/python/cpython/issues/113297]: Fix segfault in the compiler on with statement with 19 context managers.

gh-113212 [https://github.com/python/cpython/issues/113212]: Improve super error messages.

gh-111375 [https://github.com/python/cpython/issues/111375]: Only use NULL in the exception stack to indicate an exception was handled. Patch by Carey Metcalfe.

gh-112215 [https://github.com/python/cpython/issues/112215]: Increase the C recursion limit by a factor of 3 for non-debug builds, except for webassembly and s390 platforms which are unchanged. This mitigates some regressions in 3.12 with deep recursion mixing builtin (C) and Python code.

gh-113054 [https://github.com/python/cpython/issues/113054]: Fixed bug where a redundant NOP is not removed, causing an assertion to fail in the compiler in debug mode.

gh-106905 [https://github.com/python/cpython/issues/106905]: Use per AST-parser state rather than global state to track recursion depth within the AST parser to prevent potential race condition due to simultaneous parsing.

The issue primarily showed up in 3.11 by multithreaded users of ast.parse(). In 3.12 a change to when garbage collection can be triggered prevented the race condition from occurring.

gh-108866 [https://github.com/python/cpython/issues/108866]: Change the API and contract of _PyExecutorObject to return the next_instr pointer, instead of the frame, and to always execute at least one instruction.

gh-90350 [https://github.com/python/cpython/issues/90350]: Optimize builtin functions min() and max().

gh-112943 [https://github.com/python/cpython/issues/112943]: Correctly compute end column offsets for multiline tokens in the tokenize module. Patch by Pablo Galindo

gh-112125 [https://github.com/python/cpython/issues/112125]: Fix None.__ne__(None) returning NotImplemented instead of False.

gh-74616 [https://github.com/python/cpython/issues/74616]: input() now raises a ValueError when output on the terminal if the prompt contains embedded null characters instead of silently truncating it.

gh-112716 [https://github.com/python/cpython/issues/112716]: Fix SystemError in the import statement and in __reduce__() methods of builtin types when __builtins__ is not a dict.

gh-112730 [https://github.com/python/cpython/issues/112730]: Use color to highlight error locations in tracebacks. Patch by Pablo Galindo

gh-112625 [https://github.com/python/cpython/issues/112625]: Fixes a bug where a bytearray object could be cleared while iterating over an argument in the bytearray.join() method that could result in reading memory after it was freed.

gh-112660 [https://github.com/python/cpython/issues/112660]: Do not clear unexpected errors during formatting error messages for ImportError and AttributeError for modules.

gh-105967 [https://github.com/python/cpython/issues/105967]: Workaround a bug in Apple’s macOS platform zlib library where zlib.crc32() and binascii.crc32() could produce incorrect results on multi-gigabyte inputs. Including when using zipfile on zips containing large data.

gh-95754 [https://github.com/python/cpython/issues/95754]: Provide a better error message when accessing invalid attributes on partially initialized modules. The origin of the module being accessed is now included in the message to help with the common issue of shadowing other modules.

gh-112217 [https://github.com/python/cpython/issues/112217]: Add check for the type of __cause__ returned from calling the type T in raise from T.

gh-111058 [https://github.com/python/cpython/issues/111058]: Change coro.cr_frame/gen.gi_frame to return None after the coroutine/generator has been closed. This fixes a bug where getcoroutinestate() and getgeneratorstate() return the wrong state for a closed coroutine/generator.

gh-112388 [https://github.com/python/cpython/issues/112388]: Fix an error that was causing the parser to try to overwrite tokenizer errors. Patch by pablo Galindo

gh-112387 [https://github.com/python/cpython/issues/112387]: Fix error positions for decoded strings with backwards tokenize errors. Patch by Pablo Galindo

gh-99606 [https://github.com/python/cpython/issues/99606]: Make code generated for an empty f-string identical to the code of an empty normal string.

gh-112367 [https://github.com/python/cpython/issues/112367]: Avoid undefined behaviour when using the perf trampolines by not freeing the code arenas until shutdown. Patch by Pablo Galindo

gh-112320 [https://github.com/python/cpython/issues/112320]: The Tier 2 translator now tracks the confidence level for staying “on trace” (i.e. not exiting back to the Tier 1 interpreter) for branch instructions based on the number of bits set in the branch “counter”. Trace translation ends when the confidence drops below 1/3rd.

gh-109598 [https://github.com/python/cpython/issues/109598]: PyComplex_RealAsDouble()/PyComplex_ImagAsDouble() now tries to convert an object to a complex instance using its __complex__() method before falling back to the __float__() method. Patch by Sergey B Kirpichev.

gh-94606 [https://github.com/python/cpython/issues/94606]: Fix UnicodeEncodeError when email.message.get_payload() reads a message with a Unicode surrogate character and the message content is not well-formed for surrogateescape encoding. Patch by Sidney Markowitz.

bpo-21861 [https://bugs.python.org/issue?@action=redirect&bpo=21861]: Use the object’s actual class name in _io.FileIO.__repr__(), _io._WindowsConsoleIO() and _io.TextIOWrapper.__repr__(), to make these methods subclass friendly.

bpo-45369 [https://bugs.python.org/issue?@action=redirect&bpo=45369]: Remove LibreSSL workarounds as per PEP 644 [https://peps.python.org/pep-0644/].

bpo-34392 [https://bugs.python.org/issue?@action=redirect&bpo=34392]: Added sys._is_interned().

Library

gh-114077 [https://github.com/python/cpython/issues/114077]: Fix possible OverflowError in socket.socket.sendfile() when pass count larger than 2 GiB on 32-bit platform.

gh-111803 [https://github.com/python/cpython/issues/111803]: plistlib now supports loading more deeply nested lists in binary format.

gh-114014 [https://github.com/python/cpython/issues/114014]: Fixed a bug in fractions.Fraction where an invalid string using d in the decimals part creates a different error compared to other invalid letters/characters. Patch by Jeremiah Gabriel Pascual.

gh-108364 [https://github.com/python/cpython/issues/108364]: sqlite3.Connection.iterdump() now ensures that foreign key support is disabled before dumping the database schema, if there is any foreign key violation. Patch by Erlend E. Aasland and Mariusz Felisiak.

gh-113971 [https://github.com/python/cpython/issues/113971]: The zipfile.ZipInfo previously protected ._compresslevel attribute has been made public as .compress_level with the old _compresslevel name remaining available as a property to retain compatibility.

gh-113877 [https://github.com/python/cpython/issues/113877]: Fix tkinter method winfo_pathname() on 64-bit Windows.

gh-113868 [https://github.com/python/cpython/issues/113868]: Added mmap.MAP_NORESERVE, mmap.MAP_NOEXTEND, mmap.MAP_HASSEMAPHORE, mmap.MAP_NOCACHE, mmap.MAP_JIT, mmap.MAP_RESILIENT_CODESIGN, mmap.MAP_RESILIENT_MEDIA, mmap.MAP_32BIT, mmap.MAP_TRANSLATED_ALLOW_EXECUTE, mmap.MAP_UNIX03 and mmap.MAP_TPRO. All of them are mmap(2) flags on macOS.

gh-113848 [https://github.com/python/cpython/issues/113848]: asyncio.TaskGroup() and asyncio.timeout() context managers now handle CancelledError subclasses as well as exact CancelledError.

gh-113661 [https://github.com/python/cpython/issues/113661]: unittest runner: Don’t exit 5 if tests were skipped. The intention of exiting 5 was to detect issues where the test suite wasn’t discovered at all. If we skipped tests, it was correctly discovered.

gh-96037 [https://github.com/python/cpython/issues/96037]: Insert TimeoutError in the context of the exception that was raised during exiting an expired asyncio.timeout() block.

gh-113781 [https://github.com/python/cpython/issues/113781]: Silence unraisable AttributeError when warnings are emitted during Python finalization.

gh-113238 [https://github.com/python/cpython/issues/113238]: Add Anchor to importlib.resources (in order for the code to comply with the documentation)

gh-111693 [https://github.com/python/cpython/issues/111693]: asyncio.Condition.wait() now re-raises the same CancelledError instance that may have caused it to be interrupted. Fixed race condition in asyncio.Semaphore.acquire() when interrupted with a CancelledError.

gh-113791 [https://github.com/python/cpython/issues/113791]: Add CLOCK_MONOTONIC_RAW_APPROX and CLOCK_UPTIME_RAW_APPROX to time on macOS. These are clocks available on macOS 10.12 or later.

gh-112932 [https://github.com/python/cpython/issues/112932]: Restore the ability for zipfile to extractall from zip files with a “/” directory entry in them as is commonly added to zips by some wiki or bug tracker data exporters.

gh-113568 [https://github.com/python/cpython/issues/113568]: Raise deprecation warnings from pathlib.PurePath and not its private base class PurePathBase.

gh-113594 [https://github.com/python/cpython/issues/113594]: Fix UnicodeEncodeError in email when re-fold lines that contain unknown-8bit encoded part followed by non-unknown-8bit encoded part.

gh-113538 [https://github.com/python/cpython/issues/113538]: In asyncio.StreamReaderProtocol.connection_made(), there is callback that logs an error if the task wrapping the “connected callback” fails. This callback would itself fail if the task was cancelled. Prevent this by checking whether the task was cancelled first. If so, close the transport but don’t log an error.

gh-113626 [https://github.com/python/cpython/issues/113626]: Add support for the allow_code argument in the marshal module. Passing allow_code=False prevents serialization and de-serialization of code objects which is incompatible between Python versions.

gh-85567 [https://github.com/python/cpython/issues/85567]: Fix resource warnings for unclosed files in pickle and pickletools command line interfaces.

gh-113537 [https://github.com/python/cpython/issues/113537]: Support loads str in plistlib.loads().

gh-89850 [https://github.com/python/cpython/issues/89850]: Add default implementations of pickle.Pickler.persistent_id() and pickle.Unpickler.persistent_load() methods in the C implementation. Calling super().persistent_id() and super().persistent_load() in subclasses of the C implementation of pickle.Pickler and pickle.Unpickler classes no longer causes infinite recursion.

gh-113569 [https://github.com/python/cpython/issues/113569]: Indicate if there were no actual calls in unittest assert_has_calls() failure.

gh-101225 [https://github.com/python/cpython/issues/101225]: Increase the backlog for multiprocessing.connection.Listener objects created by multiprocessing.manager and multiprocessing.resource_sharer to significantly reduce the risk of getting a connection refused error when creating a multiprocessing.connection.Connection to them.

gh-113568 [https://github.com/python/cpython/issues/113568]: Raise audit events from pathlib.Path and not its private base class PathBase.

gh-113543 [https://github.com/python/cpython/issues/113543]: Make sure that webbrowser.MacOSXOSAScript sends webbrowser.open audit event.

gh-113028 [https://github.com/python/cpython/issues/113028]: When a second reference to a string appears in the input to pickle, and the Python implementation is in use, we are guaranteed that a single copy gets pickled and a single object is shared when reloaded. Previously, in protocol 0, when a string contained certain characters (e.g. newline) it resulted in duplicate objects.

gh-113421 [https://github.com/python/cpython/issues/113421]: Fix multiprocessing logger for %(filename)s.

gh-111784 [https://github.com/python/cpython/issues/111784]: Fix segfaults in the _elementtree module. Fix first segfault during deallocation of _elementtree.XMLParser instances by keeping strong reference to pyexpat module in module state for capsule lifetime. Fix second segfault which happens in the same deallocation process by keeping strong reference to _elementtree module in XMLParser structure for _elementtree module lifetime.

gh-113407 [https://github.com/python/cpython/issues/113407]: Fix import of unittest.mock when CPython is built without docstrings.

gh-113320 [https://github.com/python/cpython/issues/113320]: Fix regression in Python 3.12 where Protocol classes that were not marked as runtime-checkable would be unnecessarily introspected, potentially causing exceptions to be raised if the protocol had problematic members. Patch by Alex Waygood.

gh-53502 [https://github.com/python/cpython/issues/53502]: Add a new option aware_datetime in plistlib to loads or dumps aware datetime.

gh-113358 [https://github.com/python/cpython/issues/113358]: Fix rendering tracebacks with exceptions with a broken __getattr__

gh-113214 [https://github.com/python/cpython/issues/113214]: Fix an AttributeError during asyncio SSL protocol aborts in SSL-over-SSL scenarios.

gh-113246 [https://github.com/python/cpython/issues/113246]: Update bundled pip to 23.3.2.

gh-87264 [https://github.com/python/cpython/issues/87264]: Fixed tarfile list() method to show file type.

gh-112182 [https://github.com/python/cpython/issues/112182]: asyncio.futures.Future.set_exception() now transforms StopIteration into RuntimeError instead of hanging or other misbehavior. Patch contributed by Jamie Phan.

gh-113225 [https://github.com/python/cpython/issues/113225]: Speed up pathlib.Path.glob() by using os.DirEntry.path where possible.

gh-113149 [https://github.com/python/cpython/issues/113149]: Improve error message when a JSON array or object contains a trailing comma. Patch by Carson Radtke.

gh-113117 [https://github.com/python/cpython/issues/113117]: The subprocess module can now use the os.posix_spawn() function with close_fds=True on platforms where posix_spawn_file_actions_addclosefrom_np is available. Patch by Jakub Kulik.

gh-113199 [https://github.com/python/cpython/issues/113199]: Make http.client.HTTPResponse.read1 and http.client.HTTPResponse.readline close IO after reading all data when content length is known. Patch by Illia Volochii.

gh-113191 [https://github.com/python/cpython/issues/113191]: Add support of os.fchmod() and a file descriptor in os.chmod() on Windows.

gh-113188 [https://github.com/python/cpython/issues/113188]: Fix shutil.copymode() and shutil.copystat() on Windows. Previously they worked differently if dst is a symbolic link: they modified the permission bits of dst itself rather than the file it points to if follow_symlinks is true or src is not a symbolic link, and did not modify the permission bits if follow_symlinks is false and src is a symbolic link.

gh-113119 [https://github.com/python/cpython/issues/113119]: os.posix_spawn() now accepts env=None, which makes the newly spawned process use the current process environment. Patch by Jakub Kulik.

gh-113202 [https://github.com/python/cpython/issues/113202]: Add a strict option to batched() in the itertools module.

gh-61648 [https://github.com/python/cpython/issues/61648]: Detect line numbers of properties in doctests.

gh-113175 [https://github.com/python/cpython/issues/113175]: Sync with importlib_metadata 7.0, including improved type annotations, fixed issue with symlinked packages in package_distributions, added EntryPoints.__repr__, introduced the diagnose script, added Distribution.origin property, and removed deprecated EntryPoint access by numeric index (tuple behavior).

gh-59616 [https://github.com/python/cpython/issues/59616]: Add support of os.lchmod() and the follow_symlinks argument in os.chmod() on Windows. Note that the default value of follow_symlinks in os.lchmod() is False on Windows.

gh-112559 [https://github.com/python/cpython/issues/112559]: signal.signal() and signal.getsignal() no longer call repr on callable handlers. asyncio.run() and asyncio.Runner.run() no longer call repr on the task results. Patch by Yilei Yang.

gh-112962 [https://github.com/python/cpython/issues/112962]: dis module functions add cache information to the Instruction instance rather than creating fake Instruction instances to represent the cache entries.

gh-112989 [https://github.com/python/cpython/issues/112989]: Reduce overhead to connect sockets with asyncio SelectorEventLoop.

gh-112970 [https://github.com/python/cpython/issues/112970]: Use closefrom() on Linux where available (e.g. glibc-2.34), rather than only FreeBSD.

gh-110190 [https://github.com/python/cpython/issues/110190]: Fix ctypes structs with array on PPC64LE platform by setting MAX_STRUCT_SIZE to 64 in stgdict. Patch by Diego Russo.

gh-112540 [https://github.com/python/cpython/issues/112540]: The statistics.geometric_mean() function now returns zero for datasets containing a zero. Formerly, it would raise an exception.

gh-87286 [https://github.com/python/cpython/issues/87286]: Added LOG_FTP, LOG_NETINFO, LOG_REMOTEAUTH, LOG_INSTALL, LOG_RAS, and LOG_LAUNCHD tot the syslog module, all of them constants on used on macOS.

gh-112800 [https://github.com/python/cpython/issues/112800]: Fix asyncio SubprocessTransport.close() not to throw PermissionError when used with setuid executables.

gh-51944 [https://github.com/python/cpython/issues/51944]: Add the following constants to the termios module. These values are present in macOS system headers: ALTWERASE, B14400, B28800, B7200, B76800, CCAR_OFLOW, CCTS_OFLOW, CDSR_OFLOW, CDTR_IFLOW, CIGNORE, CRTS_IFLOW, EXTPROC, IUTF8, MDMBUF, NL2, NL3, NOKERNINFO, ONOEOT, OXTABS, VDSUSP, VSTATUS.

gh-79325 [https://github.com/python/cpython/issues/79325]: Fix an infinite recursion error in tempfile.TemporaryDirectory() cleanup on Windows.

gh-94692 [https://github.com/python/cpython/issues/94692]: shutil.rmtree() now only catches OSError exceptions. Previously a symlink attack resistant version of shutil.rmtree() could ignore or pass to the error handler arbitrary exception when invalid arguments were provided.

gh-112736 [https://github.com/python/cpython/issues/112736]: The use of del-safe symbols in subprocess was refactored to allow for use in cross-platform build environments.

gh-112727 [https://github.com/python/cpython/issues/112727]: Speed up pathlib.Path.absolute(). Patch by Barney Gale.

gh-74690 [https://github.com/python/cpython/issues/74690]: Speedup issubclass() checks against simple runtime-checkable protocols by around 6%. Patch by Alex Waygood.

gh-74690 [https://github.com/python/cpython/issues/74690]: Speedup isinstance() checks by roughly 20% for runtime-checkable protocols that only have one callable member. Speedup issubclass() checks for these protocols by roughly 10%. Patch by Alex Waygood.

gh-112645 [https://github.com/python/cpython/issues/112645]: Remove deprecation error on passing onerror to shutil.rmtree().

gh-112640 [https://github.com/python/cpython/issues/112640]: Add kwdefaults parameter to types.FunctionType to set default keyword argument values.

gh-112622 [https://github.com/python/cpython/issues/112622]: Ensure name parameter is passed to event loop in asyncio.create_task().

gh-112618 [https://github.com/python/cpython/issues/112618]: Fix a caching bug relating to typing.Annotated. Annotated[str, True] is no longer identical to Annotated[str, 1].

gh-112334 [https://github.com/python/cpython/issues/112334]: Fixed a performance regression in 3.12’s subprocess on Linux where it would no longer use the fast-path vfork() system call when it could have due to a logic bug, instead falling back to the safe but slower fork().

Also fixed a second 3.12.0 potential security bug. If a value of extra_groups=[] was passed to subprocess.Popen or related APIs, the underlying setgroups(0, NULL) system call to clear the groups list would not be made in the child process prior to exec().

This was identified via code inspection in the process of fixing the first bug.

gh-110190 [https://github.com/python/cpython/issues/110190]: Fix ctypes structs with array on Arm platform by setting MAX_STRUCT_SIZE to 32 in stgdict. Patch by Diego Russo.

gh-81194 [https://github.com/python/cpython/issues/81194]: Fix a crash in socket.if_indextoname() with specific value (UINT_MAX). Fix an integer overflow in socket.if_indextoname() on 64-bit non-Windows platforms.

gh-112578 [https://github.com/python/cpython/issues/112578]: Fix a spurious RuntimeWarning when executing the zipfile module.

gh-112516 [https://github.com/python/cpython/issues/112516]: Update the bundled copy of pip to version 23.3.1.

gh-112510 [https://github.com/python/cpython/issues/112510]: Add readline.backend for the backend readline uses (editline or readline)

gh-112328 [https://github.com/python/cpython/issues/112328]: [Enum] Make EnumDict, EnumDict.member_names, EnumType._add_alias_ and EnumType._add_value_alias_ public.

gh-112509 [https://github.com/python/cpython/issues/112509]: Fix edge cases that could cause a key to be present in both the __required_keys__ and __optional_keys__ attributes of a typing.TypedDict. Patch by Jelle Zijlstra.

gh-101336 [https://github.com/python/cpython/issues/101336]: Add keep_alive keyword parameter for AbstractEventLoop.create_server() and BaseEventLoop.create_server().

gh-63284 [https://github.com/python/cpython/issues/63284]: Added support for TLS-PSK (pre-shared key) mode to the ssl module.

gh-112414 [https://github.com/python/cpython/issues/112414]: Fix regression in Python 3.12 where calling repr() on a module that had been imported using a custom loader could fail with AttributeError. Patch by Alex Waygood.

gh-112358 [https://github.com/python/cpython/issues/112358]: Revert change to struct.Struct initialization that broke some cases of subclassing.

gh-112405 [https://github.com/python/cpython/issues/112405]: Optimize pathlib.PurePath.relative_to(). Patch by Alex Waygood.

gh-94722 [https://github.com/python/cpython/issues/94722]: Fix bug where comparison between instances of DocTest fails if one of them has None as its lineno.

gh-112361 [https://github.com/python/cpython/issues/112361]: Speed up a small handful of pathlib methods by removing some temporary objects.

gh-112345 [https://github.com/python/cpython/issues/112345]: Improve error message when trying to call issubclass() against a typing.Protocol that has non-method members. Patch by Randolf Scholz.

gh-112137 [https://github.com/python/cpython/issues/112137]: Change dis output to display no-lineno as “–” instead of “None”.

gh-112332 [https://github.com/python/cpython/issues/112332]: Deprecate the exc_type field of traceback.TracebackException. Add exc_type_str to replace it.

gh-81620 [https://github.com/python/cpython/issues/81620]: Add extra tests for random.binomialvariate()

gh-112292 [https://github.com/python/cpython/issues/112292]: Fix a crash in readline when imported from a sub interpreter. Patch by Anthony Shaw

gh-77621 [https://github.com/python/cpython/issues/77621]: Slightly improve the import time of the pathlib module by deferring some imports. Patch by Barney Gale.

gh-112137 [https://github.com/python/cpython/issues/112137]: Change dis output to display logical labels for jump targets instead of offsets.

gh-112139 [https://github.com/python/cpython/issues/112139]: Add Signature.format() to format signatures to string with extra options. And use it in pydoc to render more readable signatures that have new lines between parameters.

gh-112105 [https://github.com/python/cpython/issues/112105]: Make readline.set_completer_delims() work with libedit

gh-106922 [https://github.com/python/cpython/issues/106922]: Display multiple lines with traceback when errors span multiple lines.

gh-111874 [https://github.com/python/cpython/issues/111874]: When creating a typing.NamedTuple class, ensure __set_name__() is called on all objects that define __set_name__ and exist in the values of the NamedTuple class’s class dictionary. Patch by Alex Waygood.

gh-68166 [https://github.com/python/cpython/issues/68166]: Add support of the “vsapi” element type in tkinter.ttk.Style.element_create().

gh-110275 [https://github.com/python/cpython/issues/110275]: Named tuple’s methods _replace() and __replace__() now raise TypeError instead of ValueError for invalid keyword arguments.

gh-99367 [https://github.com/python/cpython/issues/99367]: Do not mangle sys.path[0] in pdb if safe_path is set

gh-111615 [https://github.com/python/cpython/issues/111615]: Fix a regression caused by a fix to gh-93162 [https://github.com/python/cpython/issues/93162] whereby you couldn’t configure a QueueHandler without specifying handlers.

gh-75666 [https://github.com/python/cpython/issues/75666]: Fix the behavior of tkinter widget’s unbind() method with two arguments. Previously, widget.unbind(sequence, funcid) destroyed the current binding for sequence, leaving sequence unbound, and deleted the funcid command. Now it removes only funcid from the binding for sequence, keeping other commands, and deletes the funcid command. It leaves sequence unbound only if funcid was the last bound command.

gh-67790 [https://github.com/python/cpython/issues/67790]: Implement basic formatting support (minimum width, alignment, fill) for fractions.Fraction.

gh-111049 [https://github.com/python/cpython/issues/111049]: Fix crash during garbage collection of the io.BytesIO buffer object.

gh-102980 [https://github.com/python/cpython/issues/102980]: Redirect the output of interact command of pdb to the same channel as the debugger. Add tests and improve docs.

gh-102988 [https://github.com/python/cpython/issues/102988]: email.utils.getaddresses() and email.utils.parseaddr() now return ('', '') 2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: use strict=False to get the old behavior, accept malformed inputs. getattr(email.utils, 'supports_strict_parsing', False) can be use to check if the strict parameter is available. Patch by Thomas Dwyer and Victor Stinner to improve the CVE 2023-27043 [https://www.cve.org/CVERecord?id=CVE-2023-27043] fix.

gh-52161 [https://github.com/python/cpython/issues/52161]: cmd.Cmd.do_help() now cleans docstrings with inspect.cleandoc() before writing them. Patch by Filip Łapkiewicz.

gh-82300 [https://github.com/python/cpython/issues/82300]: Add track parameter to multiprocessing.shared_memory.SharedMemory that allows using shared memory blocks without having to register with the POSIX resource tracker that automatically releases them upon process exit.

gh-110109 [https://github.com/python/cpython/issues/110109]: Add private pathlib._PurePathBase class: a base class for pathlib.PurePath that omits certain magic methods. It may be made public (along with _PathBase) in future.

gh-109858 [https://github.com/python/cpython/issues/109858]: Protect zipfile from “quoted-overlap” zipbomb. It now raises BadZipFile when try to read an entry that overlaps with other entry or central directory.

gh-109786 [https://github.com/python/cpython/issues/109786]: Fix possible reference leaks and crash when re-enter the __next__() method of itertools.pairwise.

gh-91539 [https://github.com/python/cpython/issues/91539]: Small (10 - 20%) and trivial performance improvement of urllib.request.getproxies_environment(), typically useful when there are many environment variables to go over.

gh-103363 [https://github.com/python/cpython/issues/103363]: Add follow_symlinks keyword-only argument to pathlib.Path.owner() and group(), defaulting to True.

gh-102130 [https://github.com/python/cpython/issues/102130]: Support tab completion in cmd for editline.

gh-99437 [https://github.com/python/cpython/issues/99437]: runpy.run_path() now decodes path-like objects, making sure __file__ and sys.argv[0] of the module being run are always strings.

gh-104003 [https://github.com/python/cpython/issues/104003]: Add warnings.deprecated(), a decorator to mark deprecated functions to static type checkers and to warn on usage of deprecated classes and functions. See PEP 702 [https://peps.python.org/pep-0702/]. Patch by Jelle Zijlstra.

gh-103708 [https://github.com/python/cpython/issues/103708]: Make hardcoded python name, a configurable parameter so that different implementations of python can override it instead of making huge diffs in sysconfig.py

gh-66515 [https://github.com/python/cpython/issues/66515]: mailbox.MH now supports folders that do not contain a .mh_sequences file (e.g. Claws Mail IMAP-cache folders). Patch by Serhiy Storchaka.

gh-83162 [https://github.com/python/cpython/issues/83162]: Renamed re.error to PatternError for clarity, and kept re.error for backward compatibility. Patch by Matthias Bussonnier and Adam Chhina.

gh-91133 [https://github.com/python/cpython/issues/91133]: Fix a bug in tempfile.TemporaryDirectory cleanup, which now no longer dereferences symlinks when working around file system permission errors.

bpo-43153 [https://bugs.python.org/issue?@action=redirect&bpo=43153]: On Windows, tempfile.TemporaryDirectory previously masked a PermissionError with NotADirectoryError during directory cleanup. It now correctly raises PermissionError if errors are not ignored. Patch by Andrei Kulakov and Ken Jin.

bpo-32731 [https://bugs.python.org/issue?@action=redirect&bpo=32731]: getpass.getuser() now raises OSError for all failures rather than ImportError on systems lacking the pwd module or KeyError if the password database is empty.

bpo-34321 [https://bugs.python.org/issue?@action=redirect&bpo=34321]: mmap.mmap now has a trackfd parameter on Unix; if it is False, the file descriptor specified by fileno will not be duplicated.

bpo-35332 [https://bugs.python.org/issue?@action=redirect&bpo=35332]: The shutil.rmtree() function now ignores errors when calling os.close() when ignore_errors is True, and os.close() no longer retried after error.

bpo-35928 [https://bugs.python.org/issue?@action=redirect&bpo=35928]: io.TextIOWrapper now correctly handles the decoding buffer after read() and write().

bpo-26791 [https://bugs.python.org/issue?@action=redirect&bpo=26791]: shutil.move() now moves a symlink into a directory when that directory is the target of the symlink. This provides the same behavior as the mv shell command. The previous behavior raised an exception. Patch by Jeffrey Kintscher.

bpo-41422 [https://bugs.python.org/issue?@action=redirect&bpo=41422]: Fixed memory leaks of pickle.Pickler and pickle.Unpickler involving cyclic references via the internal memo mapping.

bpo-19821 [https://bugs.python.org/issue?@action=redirect&bpo=19821]: The pydoc.ispackage() function has been deprecated.

bpo-40262 [https://bugs.python.org/issue?@action=redirect&bpo=40262]: The ssl.SSLSocket.recv_into() method no longer requires the buffer argument to implement __len__ and supports buffers with arbitrary item size.

bpo-39912 [https://bugs.python.org/issue?@action=redirect&bpo=39912]: warnings.filterwarnings() and warnings.simplefilter() now raise appropriate exceptions instead of AssertionError. Patch contributed by Rémi Lapeyre.

bpo-37260 [https://bugs.python.org/issue?@action=redirect&bpo=37260]: Fixed a race condition in shutil.rmtree() in which directory entries removed by another process or thread while shutil.rmtree() is running can cause it to raise FileNotFoundError. Patch by Jeffrey Kintscher.

bpo-36959 [https://bugs.python.org/issue?@action=redirect&bpo=36959]: Fix some error messages for invalid ISO format string combinations in strptime() that referred to directives not contained in the format string. Patch by Gordon P. Hemsley.

bpo-18060 [https://bugs.python.org/issue?@action=redirect&bpo=18060]: Fixed a class inheritance issue that can cause segfaults when deriving two or more levels of subclasses from a base class of Structure or Union.

bpo-29779 [https://bugs.python.org/issue?@action=redirect&bpo=29779]: Add a new PYTHON_HISTORY environment variable to set the location of a .python_history file.

bpo-21360 [https://bugs.python.org/issue?@action=redirect&bpo=21360]: mailbox.Maildir now ignores files with a leading dot.

Documentation

gh-111699 [https://github.com/python/cpython/issues/111699]: Relocate smtpd deprecation notice to its own section rather than under locale in What’s New in Python 3.12 document

gh-110746 [https://github.com/python/cpython/issues/110746]: Improved markup for valid options/values for methods ttk.treeview.column and ttk.treeview.heading, and for Layouts.

gh-95649 [https://github.com/python/cpython/issues/95649]: Document that the asyncio module contains code taken from v0.16.0 of the uvloop project [https://github.com/MagicStack/uvloop/tree/v0.16.0], as well as the required MIT licensing information.

Tests

gh-111798 [https://github.com/python/cpython/issues/111798]: Disable test_super_deep() from test_call under pydebug builds on WASI; the stack depth is too small to make the test useful.

gh-111801 [https://github.com/python/cpython/issues/111801]: Lower the recursion limit in test_isinstance for test_infinitely_many_bases(). This prevents a stack overflow on a pydebug build of WASI.

gh-111802 [https://github.com/python/cpython/issues/111802]: Specify a low recursion depth for test_bad_getattr() in test.pickletester to avoid exhausting the stack under a pydebug build for WASI.

gh-44626 [https://github.com/python/cpython/issues/44626]: Fix os.path.isabs() incorrectly returning True when given a path that starts with exactly one (back)slash on Windows.

Fix pathlib.PureWindowsPath.is_absolute() incorrectly returning False for some paths beginning with two (back)slashes.

gh-113633 [https://github.com/python/cpython/issues/113633]: Use module state for the _testcapi extension module.

gh-109980 [https://github.com/python/cpython/issues/109980]: Fix test_tarfile_vs_tar in test_shutil for macOS, where system tar can include more information in the archive than shutil.make_archive.

gh-112769 [https://github.com/python/cpython/issues/112769]: The tests now correctly compare zlib version when zlib.ZLIB_RUNTIME_VERSION contains non-integer suffixes. For example zlib-ng defines the version as 1.3.0.zlib-ng.

gh-112334 [https://github.com/python/cpython/issues/112334]: Adds a regression test to verify that vfork() is used when expected by subprocess on vfork enabled POSIX systems (Linux).

gh-108927 [https://github.com/python/cpython/issues/108927]: Fixed order dependence in running tests in the same process when a test that has submodules (e.g. test_importlib) follows a test that imports its submodule (e.g. test_importlib.util) and precedes a test (e.g. test_unittest or test_compileall) that uses that submodule.

bpo-40648 [https://bugs.python.org/issue?@action=redirect&bpo=40648]: Test modes that file can get with chmod() on Windows.

Build

gh-114013 [https://github.com/python/cpython/issues/114013]: Fix Tools/wasm/wasi.py to not include the path to python.wasm as part of HOSTRUNNER. The environment variable is meant to specify how to run the WASI host only, having python.wasm and relevant flags appended to the HOSTRUNNER. This fixes make test work.

gh-113258 [https://github.com/python/cpython/issues/113258]: Changed the Windows build to write out generated frozen modules into the build tree instead of the source tree.

gh-112305 [https://github.com/python/cpython/issues/112305]: Fixed the check-clean-src step performed on out of tree builds to detect errant $(srcdir)/Python/frozen_modules/*.h files and recommend appropriate source tree cleanup steps to get a working build again.

gh-112536 [https://github.com/python/cpython/issues/112536]: Add support for thread sanitizer (TSAN)

gh-112867 [https://github.com/python/cpython/issues/112867]: Fix the build for the case that WITH_PYMALLOC_RADIX_TREE=0 set.

gh-103065 [https://github.com/python/cpython/issues/103065]: Introduce Tools/wasm/wasi.py to simplify doing a WASI build.

bpo-11102 [https://bugs.python.org/issue?@action=redirect&bpo=11102]: The os.major(), os.makedev(), and os.minor() functions are now available on HP-UX v3.

bpo-36351 [https://bugs.python.org/issue?@action=redirect&bpo=36351]: Do not set ipv6type when cross-compiling.

Windows

gh-114096 [https://github.com/python/cpython/issues/114096]: Process privileges that are activated for creating directory junctions are now restored afterwards, avoiding behaviour changes in other parts of the program.

gh-111877 [https://github.com/python/cpython/issues/111877]: os.stat() calls were returning incorrect time values for files that could not be accessed directly.

gh-111973 [https://github.com/python/cpython/issues/111973]: Update Windows installer to use SQLite 3.44.2.

gh-113009 [https://github.com/python/cpython/issues/113009]: multiprocessing: On Windows, fix a race condition in Process.terminate(): no longer set the returncode attribute to always call WaitForSingleObject() in Process.wait(). Previously, sometimes the process was still running after TerminateProcess() even if GetExitCodeProcess() is not STILL_ACTIVE. Patch by Victor Stinner.

gh-86179 [https://github.com/python/cpython/issues/86179]: Fixes path calculations when launching Python on Windows through a symlink.

gh-71383 [https://github.com/python/cpython/issues/71383]: Update Tcl/Tk in Windows installer to 8.6.13 with a patch to suppress incorrect ThemeChanged warnings.

gh-111650 [https://github.com/python/cpython/issues/111650]: Ensures the Py_GIL_DISABLED preprocessor variable is defined in pyconfig.h so that extension modules written in C are able to use it.

gh-112278 [https://github.com/python/cpython/issues/112278]: Reduce the time cost for some functions in platform on Windows if current user has no permission to the WMI.

gh-73427 [https://github.com/python/cpython/issues/73427]: Deprecate sys._enablelegacywindowsfsencoding(). Use PYTHONLEGACYWINDOWSFSENCODING instead. Patch by Inada Naoki.

gh-87868 [https://github.com/python/cpython/issues/87868]: Correctly sort and remove duplicate environment variables in _winapi.CreateProcess().

bpo-37308 [https://bugs.python.org/issue?@action=redirect&bpo=37308]: Fix mojibake in mmap.mmap when using a non-ASCII tagname argument on Windows.

macOS

gh-113666 [https://github.com/python/cpython/issues/113666]: Add the following constants to module stat: UF_SETTABLE, UF_TRACKED, UF_DATAVAULT, SF_SUPPORTED, SF_SETTABLE, SF_SYNTHETIC, SF_RESTRICTED, SF_FIRMLINK and SF_DATALESS. The values UF_SETTABLE, SF_SUPPORTED, SF_SETTABLE and SF_SYNTHETIC are only available on macOS.

gh-113536 [https://github.com/python/cpython/issues/113536]: os.waitid() is now available on macOS

gh-110459 [https://github.com/python/cpython/issues/110459]: Running configure ... --with-openssl-rpath=X/Y/Z no longer fails to detect OpenSSL on macOS.

gh-74573 [https://github.com/python/cpython/issues/74573]: Document that dbm.ndbm can silently corrupt DBM files on updates when exceeding undocumented platform limits, and can crash (segmentation fault) when reading such a corrupted file. (FB8919203)

gh-65701 [https://github.com/python/cpython/issues/65701]: The freeze tool doesn’t work with framework builds of Python. Document this and bail out early when running the tool with such a build.

gh-87277 [https://github.com/python/cpython/issues/87277]: webbrowser: Don’t look for X11 browsers on macOS. Those are generally not used and probing for them can result in starting XQuartz even if it isn’t used otherwise.

gh-111973 [https://github.com/python/cpython/issues/111973]: Update macOS installer to use SQLite 3.44.2.

gh-108269 [https://github.com/python/cpython/issues/108269]: Set CFBundleAllowMixedLocalizations to true in the Info.plist for the framework, embedded Python.app and IDLE.app with framework installs on macOS. This allows applications to pick up the user’s preferred locale when that’s different from english.

gh-102362 [https://github.com/python/cpython/issues/102362]: Make sure the result of sysconfig.get_plaform() includes at least a major and minor versions, even if MACOSX_DEPLOYMENT_TARGET is set to only a major version during build to match the format expected by pip.

gh-110017 [https://github.com/python/cpython/issues/110017]: Disable a signal handling stress test on macOS due to a bug in macOS (FB13453490).

gh-110820 [https://github.com/python/cpython/issues/110820]: Make sure the preprocessor definitions for ALIGNOF_MAX_ALIGN_T, SIZEOF_LONG_DOUBLE and HAVE_GCC_ASM_FOR_X64 are correct for Universal 2 builds on macOS.

gh-109981 [https://github.com/python/cpython/issues/109981]: Use /dev/fd on macOS to determine the number of open files in test.support.os_helper.fd_count to avoid a crash with “guarded” file descriptors when probing for open files.

IDLE

gh-72284 [https://github.com/python/cpython/issues/72284]: Improve the lists of features, editor key bindings, and shell key bingings in the IDLE doc.

gh-113903 [https://github.com/python/cpython/issues/113903]: Fix rare failure of test.test_idle, in test_configdialog.

gh-113729 [https://github.com/python/cpython/issues/113729]: Fix the “Help -> IDLE Doc” menu bug in 3.11.7 and 3.12.1.

gh-113269 [https://github.com/python/cpython/issues/113269]: Fix test_editor hang on macOS Catalina.

gh-112898 [https://github.com/python/cpython/issues/112898]: Fix processing unsaved files when quitting IDLE on macOS.

bpo-13586 [https://bugs.python.org/issue?@action=redirect&bpo=13586]: Enter the selected text when opening the “Replace” dialog.

C API

gh-106560 [https://github.com/python/cpython/issues/106560]: Fix redundant declarations in the public C API. Declare PyBool_Type, PyLong_Type and PySys_Audit() only once. Patch by Victor Stinner.

gh-112438 [https://github.com/python/cpython/issues/112438]: Fix support of format units “es”, “et”, “es#”, and “et#” in nested tuples in PyArg_ParseTuple()-like functions.

gh-111545 [https://github.com/python/cpython/issues/111545]: Add Py_HashPointer() function to hash a pointer. Patch by Victor Stinner.

gh-65210 [https://github.com/python/cpython/issues/65210]: Change the declaration of the keywords parameter of PyArg_ParseTupleAndKeywords() and PyArg_VaParseTupleAndKeywords() for better compatibility with C++.

Python 3.13.0 alpha 2

Release date: 2023-11-22

Core and Builtins

gh-112243 [https://github.com/python/cpython/issues/112243]: Don’t include comments in f-string debug expressions. Patch by Pablo Galindo

gh-112287 [https://github.com/python/cpython/issues/112287]: Slightly optimize the Tier 2 (uop) interpreter by only loading oparg and operand when needed. Also double the trace size limit again, to 512 this time.

gh-112266 [https://github.com/python/cpython/issues/112266]: Change docstrings of __dict__ and __weakref__.

gh-111807 [https://github.com/python/cpython/issues/111807]: Lower the max parser stack depth to 1000 under WASI debug builds.

gh-111798 [https://github.com/python/cpython/issues/111798]: When Python is built in debug mode, set the C recursion limit to 500 instead of 1500. A debug build is likely built with low optimization level which implies higher stack memory usage than a release build. Patch by Victor Stinner.

gh-106529 [https://github.com/python/cpython/issues/106529]: Enable translating unspecialized FOR_ITER to Tier 2.

gh-111916 [https://github.com/python/cpython/issues/111916]: Make hashlib related modules thread-safe without the GIL

gh-81137 [https://github.com/python/cpython/issues/81137]: Deprecate assignment to a function’s __code__ field when the new code object is of a mismatched type (e.g., from a generator to a plain function).

gh-79932 [https://github.com/python/cpython/issues/79932]: Raise exception if frame.clear() is called on a suspended frame.

gh-81925 [https://github.com/python/cpython/issues/81925]: Implement native thread ids for GNU KFreeBSD.

gh-111843 [https://github.com/python/cpython/issues/111843]: Use exponential backoff to reduce the number of failed tier 2 optimization attempts by over 99%.

gh-110829 [https://github.com/python/cpython/issues/110829]: Joining a thread now ensures the underlying OS thread has exited. This is required for safer fork() in multi-threaded processes.

gh-109369 [https://github.com/python/cpython/issues/109369]: Make sure that tier 2 traces are de-optimized if the code is instrumented

gh-111772 [https://github.com/python/cpython/issues/111772]: Specialize slot loads and stores for _Py_T_OBJECT as well as Py_T_OBJECT_EX

gh-111666 [https://github.com/python/cpython/issues/111666]: Speed up BaseExceptionGroup.derive(), BaseExceptionGroup.subgroup(), and BaseExceptionGroup.split() by changing how they parse passed arguments.

gh-111654 [https://github.com/python/cpython/issues/111654]: Fix runtime crash when some error happens in opcode LOAD_FROM_DICT_OR_DEREF.

gh-111623 [https://github.com/python/cpython/issues/111623]: Add support for sharing tuples between interpreters using the cross-interpreter API. Patch by Anthony Shaw.

gh-111354 [https://github.com/python/cpython/issues/111354]: The oparg of YIELD_VALUE is now 1 if the instruction is part of a yield-from or await, and 0 otherwise.

The SUSPENDED frame state is now split into SUSPENDED and SUSPENDED_YIELD_FROM. This simplifies the code in _PyGen_yf.

gh-111520 [https://github.com/python/cpython/issues/111520]: Merge the Tier 1 (bytecode) and Tier 2 (micro-ops) interpreters together, moving the Tier 2 interpreter loop and switch into _PyEval_EvalFrameDefault() in Python/ceval.c. The Python/executor.c file is gone. Also the TIER_ONE and TIER_TWO macros are now handled by the code generator.

Beware! This changes the environment variables to enable micro-ops and their debugging to PYTHON_UOPS and PYTHON_LLTRACE.

gh-109181 [https://github.com/python/cpython/issues/109181]: Speed up Traceback object creation by lazily compute the line number. Patch by Pablo Galindo

gh-111420 [https://github.com/python/cpython/issues/111420]: Allow type comments in parenthesized with statements

gh-111438 [https://github.com/python/cpython/issues/111438]: Add support for sharing floats between interpreters using the cross-interpreter API. Patch by Anthony Shaw.

gh-111435 [https://github.com/python/cpython/issues/111435]: Add support for sharing of True and False between interpreters using the cross-interpreter API. Patch by Anthony Shaw.

gh-102388 [https://github.com/python/cpython/issues/102388]: Fix a bug where iso2022_jp_3 and iso2022_jp_2004 codecs read out of bounds

gh-111366 [https://github.com/python/cpython/issues/111366]: Fix an issue in the codeop that was causing SyntaxError exceptions raised in the presence of invalid syntax to not contain precise error messages. Patch by Pablo Galindo

gh-111380 [https://github.com/python/cpython/issues/111380]: Fix a bug that was causing SyntaxWarning to appear twice when parsing if invalid syntax is encountered later. Patch by Pablo galindo

gh-111374 [https://github.com/python/cpython/issues/111374]: Added a new environment variable PYTHON_FROZEN_MODULES. It determines whether or not frozen modules are ignored by the import machinery, equivalent of the -X frozen_modules command-line option.

gh-111354 [https://github.com/python/cpython/issues/111354]: Remove oparg from YIELD_VALUE. Change oparg of RESUME to include information about the except-depth. These changes make it possible to simplify the code in generator close.

gh-94438 [https://github.com/python/cpython/issues/94438]: Fix a regression that prevented jumping across is None and is not None when debugging. Patch by Savannah Ostrowski.

gh-67224 [https://github.com/python/cpython/issues/67224]: Show source lines in tracebacks when using the -c option when running Python. Patch by Pablo Galindo

gh-111123 [https://github.com/python/cpython/issues/111123]: Fix a bug where a global declaration in an except block is rejected when the global is used in the else block.

gh-110938 [https://github.com/python/cpython/issues/110938]: Fix error messages for indented blocks with functions and classes with generic type parameters. Patch by Pablo Galindo

gh-109214 [https://github.com/python/cpython/issues/109214]: Remove unnecessary instruction pointer updates before returning from frames.

gh-110912 [https://github.com/python/cpython/issues/110912]: Correctly display the traceback for MemoryError exceptions using the traceback module. Patch by Pablo Galindo

gh-109894 [https://github.com/python/cpython/issues/109894]: Fixed crash due to improperly initialized static MemoryError in subinterpreter.

gh-110892 [https://github.com/python/cpython/issues/110892]: Return NULL for PyTrace_RETURN events caused by an exception

gh-110864 [https://github.com/python/cpython/issues/110864]: Fix argument parsing by _PyArg_UnpackKeywordsWithVararg for functions defining pos-or-keyword, vararg, and kw-only parameters.

gh-109094 [https://github.com/python/cpython/issues/109094]: Replace prev_instr on the interpreter frame by instr_ptr which points to the beginning of the instruction that is currently executing (or will execute once the frame resumes).

gh-110805 [https://github.com/python/cpython/issues/110805]: Allow the repl to show source code and complete tracebacks. Patch by Pablo Galindo

gh-110722 [https://github.com/python/cpython/issues/110722]: Add PYTHON_PRESITE=package.module to import a module early in the interpreter lifecycle before site.py is executed. Python needs to be built in debug mode for this option to exist.

gh-110481 [https://github.com/python/cpython/issues/110481]: Implement biased reference counting in --disable-gil builds.

gh-110543 [https://github.com/python/cpython/issues/110543]: Fix regression in Python 3.12 where types.CodeType.replace() would produce a broken code object if called on a module or class code object that contains a comprehension. Patch by Jelle Zijlstra.

gh-89519 [https://github.com/python/cpython/issues/89519]: Removed chained classmethod descriptors (introduced in bpo-19072 [https://bugs.python.org/issue?@action=redirect&bpo=19072]). This can no longer be used to wrap other descriptors such as property. The core design of this feature was flawed and caused a number of downstream problems. To “pass-through” a classmethod, consider using the __wrapped__ attribute that was added in Python 3.10.

gh-103615 [https://github.com/python/cpython/issues/103615]: Use local events for opcode tracing

bpo-46657 [https://bugs.python.org/issue?@action=redirect&bpo=46657]: Add mimalloc memory allocator support.

gh-106718 [https://github.com/python/cpython/issues/106718]: When PyConfig.stdlib_dir is explicitly set, it’s now respected and won’t be overridden by PyConfig.home.

gh-106905 [https://github.com/python/cpython/issues/106905]: Fix incorrect SystemError about AST constructor recursion depth mismatch.

gh-100445 [https://github.com/python/cpython/issues/100445]: Improve error message for unterminated strings with escapes.

bpo-45759 [https://bugs.python.org/issue?@action=redirect&bpo=45759]: Improved error messages for elif/else statements not matching any valid statements. Patch by Jeremiah Vivian.

Library

gh-111942 [https://github.com/python/cpython/issues/111942]: Fix SystemError in the TextIOWrapper constructor with non-encodable “errors” argument in non-debug mode.

gh-111995 [https://github.com/python/cpython/issues/111995]: Added the NI_IDN constant to the socket module when present in C at build time for use with socket.getnameinfo().

gh-109538 [https://github.com/python/cpython/issues/109538]: Issue warning message instead of having RuntimeError be displayed when event loop has already been closed at StreamWriter.__del__().

gh-111942 [https://github.com/python/cpython/issues/111942]: Fix crashes in io.TextIOWrapper.reconfigure() when pass invalid arguments, e.g. non-string encoding.

gh-111460 [https://github.com/python/cpython/issues/111460]: curses: restore wide character support (including curses.unget_wch() and get_wch()) on macOS, which was unavailable due to a regression in Python 3.12.

gh-103791 [https://github.com/python/cpython/issues/103791]: contextlib.suppress now supports suppressing exceptions raised as part of a BaseExceptionGroup, in addition to the recent support for ExceptionGroup.

gh-111835 [https://github.com/python/cpython/issues/111835]: The mmap.mmap class now has an seekable() method that can be used when a seekable file-like object is required. The seek() method now returns the new absolute position. Patch by Donghee Na.

gh-111804 [https://github.com/python/cpython/issues/111804]: Remove posix.fallocate() under WASI as the underlying posix_fallocate() is not available in WASI preview2.

gh-111841 [https://github.com/python/cpython/issues/111841]: Fix truncating arguments on an embedded null character in os.putenv() and os.unsetenv() on Windows.

gh-111768 [https://github.com/python/cpython/issues/111768]: wsgiref.util.is_hop_by_hop() is now exposed correctly in __all__.

gh-80731 [https://github.com/python/cpython/issues/80731]: Avoid executing the default function in cmd.Cmd in an except block

gh-111541 [https://github.com/python/cpython/issues/111541]: Fix doctest for SyntaxError not-builtin subclasses.

gh-111719 [https://github.com/python/cpython/issues/111719]: Add extra argument validation for alias command in pdb

gh-111482 [https://github.com/python/cpython/issues/111482]: time: Make time.clock_gettime() and time.clock_gettime_ns() functions up to 2x faster by faster calling convention. Patch by Victor Stinner.

gh-110894 [https://github.com/python/cpython/issues/110894]: Call loop exception handler for exceptions in client_connected_cb of asyncio.start_server() so that applications can handle it. Patch by Kumar Aditya.

gh-111531 [https://github.com/python/cpython/issues/111531]: Fix reference leaks in bind_class() and bind_all() methods of tkinter widgets.

gh-111246 [https://github.com/python/cpython/issues/111246]: asyncio.loop.create_unix_server() will now automatically remove the Unix socket when the server is closed.

gh-111356 [https://github.com/python/cpython/issues/111356]: Added io.text_encoding(), io.DEFAULT_BUFFER_SIZE, and io.IncrementalNewlineDecoder to io.__all__.

gh-66425 [https://github.com/python/cpython/issues/66425]: Remove the code to set the REMOTE_HOST header from wsgiref module, as it is unreachable. This header is used for performance reasons, which is not necessary in the wsgiref module.

gh-111429 [https://github.com/python/cpython/issues/111429]: Speed up pathlib.PurePath.relative_to() and is_relative_to().

gh-111342 [https://github.com/python/cpython/issues/111342]: Fixed typo in math.sumprod().

gh-68166 [https://github.com/python/cpython/issues/68166]: Remove mention of not supported “vsapi” element type in tkinter.ttk.Style.element_create(). Add tests for element_create() and other ttk.Style methods. Add examples for element_create() in the documentation.

gh-111388 [https://github.com/python/cpython/issues/111388]: Add show_group parameter to traceback.format_exception_only(), which allows to format ExceptionGroup instances.

gh-79033 [https://github.com/python/cpython/issues/79033]: Another attempt at fixing asyncio.Server.wait_closed(). It now blocks until both conditions are true: the server is closed, and there are no more active connections. (This means that in some cases where in 3.12.0 this function would incorrectly have returned immediately, it will now block; in particular, when there are no active connections but the server hasn’t been closed yet.)

gh-111259 [https://github.com/python/cpython/issues/111259]: Optimize recursive wildcards in pathlib.

gh-111295 [https://github.com/python/cpython/issues/111295]: Fix time not checking for errors when initializing.

gh-111253 [https://github.com/python/cpython/issues/111253]: Add error checking during _socket module init.

gh-111251 [https://github.com/python/cpython/issues/111251]: Fix _blake2 not checking for errors when initializing.

gh-111233 [https://github.com/python/cpython/issues/111233]: Fix select not checking for errors when initializing.

gh-111230 [https://github.com/python/cpython/issues/111230]: Fix ssl not checking for errors when initializing.

gh-111174 [https://github.com/python/cpython/issues/111174]: Fix crash in io.BytesIO.getbuffer() called repeatedly for empty BytesIO.

gh-111187 [https://github.com/python/cpython/issues/111187]: Postpone removal version for locale.getdefaultlocale() to Python 3.15.

gh-111159 [https://github.com/python/cpython/issues/111159]: Fix doctest output comparison for exceptions with notes.

gh-110910 [https://github.com/python/cpython/issues/110910]: Fix invalid state handling in asyncio.TaskGroup and asyncio.Timeout. They now raise proper RuntimeError if they are improperly used and are left in consistent state after this.

gh-111092 [https://github.com/python/cpython/issues/111092]: Make turtledemo run without default root enabled.

gh-110944 [https://github.com/python/cpython/issues/110944]: Support alias and convenience vars for pdb completion

gh-110745 [https://github.com/python/cpython/issues/110745]: Added newline parameter to pathlib.Path.read_text(). Patch by Junya Okabe.

gh-84583 [https://github.com/python/cpython/issues/84583]: Make pdb enter post-mortem mode even for SyntaxError

gh-80675 [https://github.com/python/cpython/issues/80675]: Set f_trace_lines = True on all frames upon pdb.set_trace()

gh-110771 [https://github.com/python/cpython/issues/110771]: Expose the setup and cleanup portions of asyncio.run_forever() as the standalone methods asyncio.run_forever_setup() and asyncio.run_forever_cleanup(). This allows for tighter integration with GUI event loops.

gh-110774 [https://github.com/python/cpython/issues/110774]: Support setting the asyncio.Runner loop_factory kwarg in unittest.IsolatedAsyncioTestCase

gh-110392 [https://github.com/python/cpython/issues/110392]: Fix tty.setraw() and tty.setcbreak(): previously they returned partially modified list of the original tty attributes. tty.cfmakeraw() and tty.cfmakecbreak() now make a copy of the list of special characters before modifying it.

gh-59013 [https://github.com/python/cpython/issues/59013]: Make line number of function breakpoint more precise in pdb

gh-88434 [https://github.com/python/cpython/issues/88434]: Emit deprecation warning for non-integer numbers in gettext functions and methods that consider plural forms even if the translation was not found.

gh-110395 [https://github.com/python/cpython/issues/110395]: Ensure that select.kqueue() objects correctly appear as closed in forked children, to prevent operations on an invalid file descriptor.

gh-110196 [https://github.com/python/cpython/issues/110196]: Add __reduce__ method to IPv6Address in order to keep scope_id

gh-109747 [https://github.com/python/cpython/issues/109747]: Improve errors for unsupported look-behind patterns. Now re.error is raised instead of OverflowError or RuntimeError for too large width of look-behind pattern.

gh-109466 [https://github.com/python/cpython/issues/109466]: Add the ipaddress.IPv4Address.ipv6_mapped property, which returns the IPv4-mapped IPv6 address.

gh-85098 [https://github.com/python/cpython/issues/85098]: Implement the CLI of the symtable module and improve the repr of Symbol.

gh-108791 [https://github.com/python/cpython/issues/108791]: Improved error handling in pdb command line interface, making it produce more concise error messages.

gh-105931 [https://github.com/python/cpython/issues/105931]: Change compileall to only strip the stripdir prefix from the full path recorded in the compiled .pyc file, when the prefix matches the start of the full path in its entirety. When the prefix does not match, no stripping is performed and a warning to this effect is displayed.

Previously all path components of the stripdir prefix that matched the full path were removed, while those that did not match were left alone (including ones interspersed between matching components).

gh-107431 [https://github.com/python/cpython/issues/107431]: Make the DictProxy and ListProxy types in multiprocessing.managers Generic Alias Types for [] use in typing contexts.

gh-72904 [https://github.com/python/cpython/issues/72904]: Add glob.translate(). This function converts a pathname with shell-style wildcards to a regular expression.

gh-90026 [https://github.com/python/cpython/issues/90026]: Define USE_XATTRS on Cygwin so that XATTR-related functions in the os module become available.

gh-90890 [https://github.com/python/cpython/issues/90890]: New methods mailbox.Maildir.get_info(), mailbox.Maildir.set_info(), mailbox.Maildir.get_flags(), mailbox.Maildir.set_flags(), mailbox.Maildir.add_flag(), mailbox.Maildir.remove_flag(). These methods speed up accessing a message’s info and/or flags and are useful when it is not necessary to access the message’s contents, as when iterating over a Maildir to find messages with specific flags.

gh-102956 [https://github.com/python/cpython/issues/102956]: Fix returning of empty byte strings after seek in zipfile module

gh-102895 [https://github.com/python/cpython/issues/102895]: Added a parameter local_exit for code.interact() to prevent exit() and quit from closing sys.stdin and raise SystemExit.

gh-97928 [https://github.com/python/cpython/issues/97928]: Change the behavior of tkinter.Text.count(). It now always returns an integer if one or less counting options are specified. Previously it could return a single count as a 1-tuple, an integer (only if option "update" was specified) or None if no items found. The result is now the same if wantobjects is set to 0.

gh-96954 [https://github.com/python/cpython/issues/96954]: Switch the storage of the unicode codepoint names to use a different data-structure, a directed acyclic word graph [https://en.wikipedia.org/wiki/Deterministic_acyclic_finite_state_automaton]. This makes the unicodedata shared library about 440 KiB smaller. Contributed by Carl Friedrich Bolz-Tereick using code from the PyPy project.

gh-73561 [https://github.com/python/cpython/issues/73561]: Omit the interface scope from an IPv6 address when used as Host header by http.client.

gh-86826 [https://github.com/python/cpython/issues/86826]: zipinfo now supports the full range of values in the TZ string determined by RFC 8536 and detects all invalid formats. Both Python and C implementations now raise exceptions of the same type on invalid data.

Tests

gh-111808 [https://github.com/python/cpython/issues/111808]: Make the default value of test.support.infinite_recursion() to be conditional based on whether optimizations were used when compiling the interpreter. This helps with platforms like WASI whose stack size is greatly restricted in debug builds.

gh-110722 [https://github.com/python/cpython/issues/110722]: Gathering line coverage of standard libraries within the regression test suite is now precise, as well as much faster. Patch by Łukasz Langa.

gh-110367 [https://github.com/python/cpython/issues/110367]: Make regrtest --verbose3 option compatible with --huntrleaks -jN options. The ./python -m test -j1 -R 3:3 --verbose3 command now works as expected. Patch by Victor Stinner.

gh-111165 [https://github.com/python/cpython/issues/111165]: Remove no longer used functions run_unittest() and run_doctest() from the test.support module.

gh-110932 [https://github.com/python/cpython/issues/110932]: Fix regrtest if the SOURCE_DATE_EPOCH environment variable is defined: use the variable value as the random seed. Patch by Victor Stinner.

gh-110995 [https://github.com/python/cpython/issues/110995]: test_gdb: Fix detection of gdb built without Python scripting support. Patch by Victor Stinner.

gh-110918 [https://github.com/python/cpython/issues/110918]: Test case matching patterns specified by options --match, --ignore, --matchfile and --ignorefile are now tested in the order of specification, and the last match determines whether the test case be run or ignored.

gh-108747 [https://github.com/python/cpython/issues/108747]: Add unit test for usercustomize and sitecustomize hooks from site.

Build

gh-96954 [https://github.com/python/cpython/issues/96954]: Make make regen-unicodedata work for out-of-tree builds of CPython.

gh-112088 [https://github.com/python/cpython/issues/112088]: Add Tools/build/regen-configure.sh script to regenerate the configure with an Ubuntu container image. The quay.io/tiran/cpython_autoconf:271 container image (tiran/cpython_autoconf [https://github.com/tiran/cpython_autoconf]) is no longer used. Patch by Victor Stinner.

gh-111046 [https://github.com/python/cpython/issues/111046]: For wasi-threads, memory is now exported to fix compatibility issues with some wasm runtimes.

gh-110828 [https://github.com/python/cpython/issues/110828]: AIX 32bit needs -latomic to build the _testcapi extension module.

gh-85283 [https://github.com/python/cpython/issues/85283]: The errno, md5, resource, winsound, _ctypes_test, _multiprocessing.posixshmem, _scproxy, _stat, _testimportmultiple and _uuid C extensions are now built with the limited C API. Patch by Victor Stinner.

Windows

gh-111856 [https://github.com/python/cpython/issues/111856]: Fixes fstat() on file systems that do not support file ID requests. This includes FAT32 and exFAT.

gh-111293 [https://github.com/python/cpython/issues/111293]: Fix os.DirEntry.inode dropping higher 64 bits of a file id on some filesystems on Windows.

gh-110913 [https://github.com/python/cpython/issues/110913]: WindowsConsoleIO now correctly chunks large buffers without splitting up UTF-8 sequences.

macOS

gh-59703 [https://github.com/python/cpython/issues/59703]: For macOS framework builds, in getpath.c use the system dladdr function to find the path to the shared library rather than depending on deprecated macOS APIs.

gh-110950 [https://github.com/python/cpython/issues/110950]: Update macOS installer to include an upstream Tcl/Tk fix for the Secure coding is not enabled for restorable state! warning encountered in Tkinter on macOS 14 Sonoma.

gh-111015 [https://github.com/python/cpython/issues/111015]: Ensure that IDLE.app and Python Launcher.app are installed with appropriate permissions on macOS builds.

gh-71383 [https://github.com/python/cpython/issues/71383]: Update macOS installer to include an upstream Tcl/Tk fix for the ttk::ThemeChanged error encountered in Tkinter.

gh-92603 [https://github.com/python/cpython/issues/92603]: Update macOS installer to include a fix accepted by upstream Tcl/Tk for a crash encountered after the first tkinter.Tk() instance is destroyed.

IDLE

bpo-35668 [https://bugs.python.org/issue?@action=redirect&bpo=35668]: Add docstrings to the IDLE debugger module. Fix two bugs: initialize Idb.botframe (should be in Bdb); in Idb.in_rpc_code, check whether prev_frame is None before trying to use it. Greatly expand test_debugger.

Tools/Demos

gh-111903 [https://github.com/python/cpython/issues/111903]: Argument Clinic now supports the @critical_section directive that instructs Argument Clinic to generate a critical section around the function call, which locks the self object in --disable-gil builds. Patch by Sam Gross.

C API

gh-112026 [https://github.com/python/cpython/issues/112026]: Add again the private _PyThreadState_UncheckedGet() function as an alias to the new public PyThreadState_GetUnchecked() function. Patch by Victor Stinner.

gh-112026 [https://github.com/python/cpython/issues/112026]: Restore the removed _PyDict_GetItemStringWithError() function. It is used by numpy. Patch by Victor Stinner.

gh-112026 [https://github.com/python/cpython/issues/112026]: Restore removed private C API functions, macros and structures which have no simple replacement for now:

_PyDict_GetItem_KnownHash()

_PyDict_NewPresized()

_PyHASH_BITS

_PyHASH_IMAG

_PyHASH_INF

_PyHASH_MODULUS

_PyHASH_MULTIPLIER

_PyLong_Copy()

_PyLong_FromDigits()

_PyLong_New()

_PyLong_Sign()

_PyObject_CallMethodId()

_PyObject_CallMethodNoArgs()

_PyObject_CallMethodOneArg()

_PyObject_CallOneArg()

_PyObject_EXTRA_INIT

_PyObject_FastCallDict()

_PyObject_GetAttrId()

_PyObject_Vectorcall()

_PyObject_VectorcallMethod()

_PyStack_AsDict()

_PyThread_CurrentFrames()

_PyUnicodeWriter structure

_PyUnicodeWriter_Dealloc()

_PyUnicodeWriter_Finish()

_PyUnicodeWriter_Init()

_PyUnicodeWriter_Prepare()

_PyUnicodeWriter_PrepareKind()

_PyUnicodeWriter_WriteASCIIString()

_PyUnicodeWriter_WriteChar()

_PyUnicodeWriter_WriteLatin1String()

_PyUnicodeWriter_WriteStr()

_PyUnicodeWriter_WriteSubstring()

_PyUnicode_AsString()

_PyUnicode_FromId()

_PyVectorcall_Function()

_Py_IDENTIFIER()

_Py_c_abs()

_Py_c_diff()

_Py_c_neg()

_Py_c_pow()

_Py_c_prod()

_Py_c_quot()

_Py_c_sum()

_Py_static_string()

_Py_static_string_init()

Patch by Victor Stinner.

gh-112026 [https://github.com/python/cpython/issues/112026]: Add again <ctype.h> and <unistd.h> includes in Python.h, but don’t include them in the limited C API version 3.13 and newer. Patch by Victor Stinner.

gh-111956 [https://github.com/python/cpython/issues/111956]: Add internal-only one-time initialization API: _PyOnceFlag and _PyOnceFlag_CallOnce.

gh-111262 [https://github.com/python/cpython/issues/111262]: Add PyDict_Pop() and PyDict_PopString() functions: remove a key from a dictionary and optionally return the removed value. This is similar to dict.pop(), but without the default value and not raising KeyError if the key missing. Patch by Stefan Behnel and Victor Stinner.

gh-111863 [https://github.com/python/cpython/issues/111863]: Rename Py_NOGIL to Py_GIL_DISABLED. Patch by Hugo van Kemenade.

gh-111138 [https://github.com/python/cpython/issues/111138]: Add PyList_Extend() and PyList_Clear() functions: similar to Python list.extend() and list.clear() methods. Patch by Victor Stinner.

gh-108765 [https://github.com/python/cpython/issues/108765]: On Windows, Python.h no longer includes the <stddef.h> standard header file. If needed, it should now be included explicitly. Patch by Victor Stinner.

gh-111569 [https://github.com/python/cpython/issues/111569]: Implement “Python Critical Sections” from PEP 703 [https://peps.python.org/pep-0703/]. These are macros to help replace the GIL with per-object locks in the --disable-gil build of CPython. The macros are no-ops in the default build.

gh-111506 [https://github.com/python/cpython/issues/111506]: In the limited C API version 3.13, Py_SET_REFCNT() function is now implemented as an opaque function call. Patch by Victor Stinner.

gh-108082 [https://github.com/python/cpython/issues/108082]: Add PyErr_FormatUnraisable() function.

gh-110964 [https://github.com/python/cpython/issues/110964]: Move the undocumented private _PyArg functions and _PyArg_Parser structure to internal C API (pycore_modsupport.h). Patch by Victor Stinner.

gh-110815 [https://github.com/python/cpython/issues/110815]: Support non-ASCII keyword names in PyArg_ParseTupleAndKeywords().

gh-109587 [https://github.com/python/cpython/issues/109587]: Introduced PyUnstable_PerfTrampoline_CompileCode(), PyUnstable_PerfTrampoline_SetPersistAfterFork() and PyUnstable_CopyPerfMapFile(). These functions allow extension modules to initialize trampolines eagerly, after the application is “warmed up”. This makes it possible to have perf-trampolines running in an always-enabled fashion.

gh-85283 [https://github.com/python/cpython/issues/85283]: Add the PySys_Audit() function to the limited C API. Patch by Victor Stinner.

gh-85283 [https://github.com/python/cpython/issues/85283]: Add PyMem_RawMalloc(), PyMem_RawCalloc(), PyMem_RawRealloc() and PyMem_RawFree() to the limited C API. Patch by Victor Stinner.

gh-106672 [https://github.com/python/cpython/issues/106672]: Functions PyDict_GetItem(), PyDict_GetItemString(), PyMapping_HasKey(), PyMapping_HasKeyString(), PyObject_HasAttr(), PyObject_HasAttrString(), and PySys_GetObject(), which clear all errors occurred during calling the function, report now them using sys.unraisablehook().

gh-67565 [https://github.com/python/cpython/issues/67565]: Remove redundant C-contiguity check in getargs.c, binascii, ssl and Argument Clinic. Patched by Stefan Krah and Furkan Onder

Python 3.13.0 alpha 1

Release date: 2023-10-13

Security

gh-108310 [https://github.com/python/cpython/issues/108310]: Fixed an issue where instances of ssl.SSLSocket were vulnerable to a bypass of the TLS handshake and included protections (like certificate verification) and treating sent unencrypted data as if it were post-handshake TLS encrypted data. Security issue reported as CVE 2023-40217 [https://www.cve.org/CVERecord?id=CVE-2023-40217] by Aapo Oksman. Patch by Gregory P. Smith.

gh-107774 [https://github.com/python/cpython/issues/107774]: PEP 669 specifies that sys.monitoring.register_callback will generate an audit event. Pre-releases of Python 3.12 did not generate the audit event. This is now fixed.

gh-102988 [https://github.com/python/cpython/issues/102988]: Reverted the email.utils security improvement change released in 3.12beta4 that unintentionally caused email.utils.getaddresses to fail to parse email addresses with a comma in the quoted name field. See gh-106669 [https://github.com/python/cpython/issues/106669].

gh-99108 [https://github.com/python/cpython/issues/99108]: Refresh our new HACL* built-in hashlib code from upstream. Built-in SHA2 should be faster and an issue with SHA3 on 32-bit platforms is fixed.

gh-102509 [https://github.com/python/cpython/issues/102509]: Start initializing ob_digit during creation of PyLongObject objects. Patch by Illia Volochii.

Core and Builtins

gh-110782 [https://github.com/python/cpython/issues/110782]: Fix crash when typing.TypeVar is constructed with a keyword argument. Patch by Jelle Zijlstra.

gh-110752 [https://github.com/python/cpython/issues/110752]: Reset ceval.eval_breaker in interpreter_clear()

gh-110721 [https://github.com/python/cpython/issues/110721]: Use the traceback implementation for the default PyErr_Display() functionality. Patch by Pablo Galindo

gh-110696 [https://github.com/python/cpython/issues/110696]: Fix incorrect error message for invalid argument unpacking. Patch by Pablo Galindo

gh-104169 [https://github.com/python/cpython/issues/104169]: Split the tokenizer into two separate directories: - One part includes the actual lexeme producing logic and lives in Parser/lexer. - The second part wraps the lexer according to the different tokenization modes we have (string, utf-8, file, interactive, readline) and lives in Parser/tokenizer.

gh-110688 [https://github.com/python/cpython/issues/110688]: Remove undocumented test_c_api method from set, which was only defined for testing purposes under Py_DEBUG. Now we have proper CAPI tests.

gh-104584 [https://github.com/python/cpython/issues/104584]: Fix a reference leak when running with PYTHONUOPS or -X uops enabled.

gh-110514 [https://github.com/python/cpython/issues/110514]: Add PY_THROW to sys.setprofile() events

gh-110489 [https://github.com/python/cpython/issues/110489]: Optimise math.ceil() when the input is exactly a float, resulting in about a 10% improvement.

gh-110455 [https://github.com/python/cpython/issues/110455]: Guard assert(tstate->thread_id > 0) with #ifndef HAVE_PTHREAD_STUBS. This allows for for pydebug builds to work under WASI which (currently) lacks thread support.

gh-110309 [https://github.com/python/cpython/issues/110309]: Remove unnecessary empty constant nodes in the ast of f-string specs.

gh-110259 [https://github.com/python/cpython/issues/110259]: Correctly identify the format spec in f-strings (with single or triple quotes) that have multiple lines in the expression part and include a formatting spec. Patch by Pablo Galindo

gh-110237 [https://github.com/python/cpython/issues/110237]: Fix missing error checks for calls to PyList_Append in _PyEval_MatchClass.

gh-110164 [https://github.com/python/cpython/issues/110164]: regrtest: If the SOURCE_DATE_EPOCH environment variable is defined, regrtest now disables tests randomization. Patch by Victor Stinner.

gh-109889 [https://github.com/python/cpython/issues/109889]: Fix the compiler’s redundant NOP detection algorithm to skip over NOPs with no line number when looking for the next instruction’s lineno.

gh-109853 [https://github.com/python/cpython/issues/109853]: sys.path[0] is now set correctly for subinterpreters.

gh-109923 [https://github.com/python/cpython/issues/109923]: Set line number on the POP_TOP that follows a RETURN_GENERATOR.

gh-105716 [https://github.com/python/cpython/issues/105716]: Subinterpreters now correctly handle the case where they have threads running in the background. Before, such threads would interfere with cleaning up and destroying them, as well as prevent running another script.

gh-109369 [https://github.com/python/cpython/issues/109369]: The internal eval_breaker and supporting flags, plus the monitoring version have been merged into a single atomic integer to speed up checks.

gh-109823 [https://github.com/python/cpython/issues/109823]: Fix bug where compiler does not adjust labels when removing an empty basic block which is a jump target.

gh-109793 [https://github.com/python/cpython/issues/109793]: The main thread no longer exits prematurely when a subinterpreter is cleaned up during runtime finalization. The bug was a problem particularly because, when triggered, the Python process would always return with a 0 exitcode, even if it failed.

gh-109719 [https://github.com/python/cpython/issues/109719]: Fix missing jump target labels when compiler reorders cold/warm blocks.

gh-109595 [https://github.com/python/cpython/issues/109595]: Add -X cpu_count command line option to override return results of os.cpu_count() and os.process_cpu_count(). This option is useful for users who need to limit CPU resources of a container system without having to modify the container (application code). Patch by Donghee Na.

gh-109627 [https://github.com/python/cpython/issues/109627]: Fix bug where the compiler does not assign a new jump target label to a duplicated small exit block.

gh-109596 [https://github.com/python/cpython/issues/109596]: Fix some tokens in the grammar that were incorrectly marked as soft keywords. Also fix some repeated rule names and ensure that repeated rules are not allowed. Patch by Pablo Galindo

gh-109496 [https://github.com/python/cpython/issues/109496]: On a Python built in debug mode, Py_DECREF() now calls _Py_NegativeRefcount() if the object is a dangling pointer to deallocated memory: memory filled with 0xDD “dead byte” by the debug hook on memory allocators. The fix is to check the reference count before checking for _Py_IsImmortal(). Patch by Victor Stinner.

gh-107265 [https://github.com/python/cpython/issues/107265]: Deopt opcodes hidden by the executor when base opcode is needed

gh-109371 [https://github.com/python/cpython/issues/109371]: Deopted instructions correctly for tool initialization and modified the incorrect assertion in instrumentation, when a previous tool already sets INSTRUCTION events

gh-105658 [https://github.com/python/cpython/issues/105658]: Fix bug where the line trace of an except block ending with a conditional includes an excess event with the line of the conditional expression.

gh-109219 [https://github.com/python/cpython/issues/109219]: Fix compiling type param scopes that use a name which is also free in an inner scope.

gh-109351 [https://github.com/python/cpython/issues/109351]: Fix crash when compiling an invalid AST involving a named (walrus) expression.

gh-109341 [https://github.com/python/cpython/issues/109341]: Fix crash when compiling an invalid AST involving a ast.TypeAlias.

gh-109195 [https://github.com/python/cpython/issues/109195]: Fix source location for the LOAD_* instruction preceding a LOAD_SUPER_ATTR to load the super global (or shadowing variable) so that it encompasses only the name super and not the following parentheses.

gh-109256 [https://github.com/python/cpython/issues/109256]: Opcode IDs for specialized opcodes are allocated in their own range to improve stability of the IDs for the ‘real’ opcodes.

gh-109216 [https://github.com/python/cpython/issues/109216]: Fix possible memory leak in BUILD_MAP.

gh-109207 [https://github.com/python/cpython/issues/109207]: Fix a SystemError in __repr__ of symtable entry object.

gh-109179 [https://github.com/python/cpython/issues/109179]: Fix bug where the C traceback display drops notes from SyntaxError.

gh-109118 [https://github.com/python/cpython/issues/109118]: Disallow nested scopes (lambdas, generator expressions, and comprehensions) within PEP 695 annotation scopes that are nested within classes.

gh-109156 [https://github.com/python/cpython/issues/109156]: Add tests for de-instrumenting instructions while keeping the instrumentation for lines

gh-109114 [https://github.com/python/cpython/issues/109114]: Relax the detection of the error message for invalid lambdas inside f-strings to not search for arbitrary replacement fields to avoid false positives. Patch by Pablo Galindo

gh-105848 [https://github.com/python/cpython/issues/105848]: Add a new CALL_KW opcode, used for calls containing keyword arguments. Also, fix a possible crash when jumping over method calls in a debugger.

gh-109052 [https://github.com/python/cpython/issues/109052]: Use the base opcode when comparing code objects to avoid interference from instrumentation

gh-109118 [https://github.com/python/cpython/issues/109118]: Fix interpreter crash when a NameError is raised inside the type parameters of a generic class.

gh-88943 [https://github.com/python/cpython/issues/88943]: Improve syntax error for non-ASCII character that follows a numerical literal. It now points on the invalid non-ASCII character, not on the valid numerical literal.

gh-108976 [https://github.com/python/cpython/issues/108976]: Fix crash that occurs after de-instrumenting a code object in a monitoring callback.

gh-108732 [https://github.com/python/cpython/issues/108732]: Make iteration variables of module- and class-scoped comprehensions visible to pdb and other tools that use frame.f_locals again.

gh-108959 [https://github.com/python/cpython/issues/108959]: Fix caret placement for error locations for subscript and binary operations that involve non-semantic parentheses and spaces. Patch by Pablo Galindo

gh-104584 [https://github.com/python/cpython/issues/104584]: Fix a crash when running with PYTHONUOPS or -X uops enabled and an error occurs during optimization.

gh-108727 [https://github.com/python/cpython/issues/108727]: Define tp_dealloc for CounterOptimizer_Type. This fixes a segfault on deallocation.

gh-108520 [https://github.com/python/cpython/issues/108520]: Fix multiprocessing.synchronize.SemLock.__setstate__() to properly initialize multiprocessing.synchronize.SemLock._is_fork_ctx. This fixes a regression when passing a SemLock across nested processes.

Rename multiprocessing.synchronize.SemLock.is_fork_ctx to multiprocessing.synchronize.SemLock._is_fork_ctx to avoid exposing it as public API.

gh-108654 [https://github.com/python/cpython/issues/108654]: Restore locals shadowed by an inlined comprehension if the comprehension raises an exception.

gh-108488 [https://github.com/python/cpython/issues/108488]: Change the initialization of inline cache entries so that the cache entry for JUMP_BACKWARD is initialized to zero, instead of the adaptive_counter_warmup() value used for all other instructions. This counter, unique among instructions, counts up from zero.

gh-108716 [https://github.com/python/cpython/issues/108716]: Turn off deep-freezing of code objects. Modules are still frozen, so that a file system search is not needed for common modules.

gh-108614 [https://github.com/python/cpython/issues/108614]: Add RESUME_CHECK instruction, to avoid having to handle instrumentation, signals, and contexts switches in the tier 2 execution engine.

gh-108487 [https://github.com/python/cpython/issues/108487]: Move an assert that would cause a spurious crash in a devious case that should only trigger deoptimization.

gh-106176 [https://github.com/python/cpython/issues/106176]: Use a WeakValueDictionary to track the lists containing the modules each thread is currently importing. This helps avoid a reference leak from keeping the list around longer than necessary. Weakrefs are used as GC can’t interrupt the cleanup.

gh-105481 [https://github.com/python/cpython/issues/105481]: The regen-opcode build stage was removed and its work is now done in regen-cases.

gh-107901 [https://github.com/python/cpython/issues/107901]: Fix missing line number on JUMP_BACKWARD at the end of a for loop.

gh-108113 [https://github.com/python/cpython/issues/108113]: The compile() built-in can now accept a new flag, ast.PyCF_OPTIMIZED_AST, which is similar to ast.PyCF_ONLY_AST except that the returned AST is optimized according to the value of the optimize argument.

ast.parse() now accepts an optional argument optimize which is passed on to the compile() built-in. This makes it possible to obtain an optimized AST.

gh-107971 [https://github.com/python/cpython/issues/107971]: Opcode IDs are generated from bytecodes.c instead of being hard coded in opcode.py.

gh-107944 [https://github.com/python/cpython/issues/107944]: Improve error message for function calls with bad keyword arguments. Patch by Pablo Galindo

gh-108390 [https://github.com/python/cpython/issues/108390]: Raise an exception when setting a non-local event (RAISE, EXCEPTION_HANDLED, etc.) in sys.monitoring.set_local_events.

Fixes crash when tracing in recursive calls to Python classes.

gh-108035 [https://github.com/python/cpython/issues/108035]: Remove the _PyCFrame struct, moving the pointer to the current interpreter frame back to the threadstate, as it was for 3.10 and earlier. The _PyCFrame existed as a performance optimization for tracing. Since PEP 669 has been implemented, this optimization no longer applies.

gh-91051 [https://github.com/python/cpython/issues/91051]: Fix abort / segfault when using all eight type watcher slots, on platforms where char is signed by default.

gh-106581 [https://github.com/python/cpython/issues/106581]: Fix possible assertion failures and missing instrumentation events when PYTHONUOPS or -X uops is enabled.

gh-107526 [https://github.com/python/cpython/issues/107526]: Revert converting vars, dir, next, getattr, and iter to argument clinic.

gh-84805 [https://github.com/python/cpython/issues/84805]: Autogenerate signature for METH_NOARGS and METH_O extension functions.

gh-107758 [https://github.com/python/cpython/issues/107758]: Make the dump_stack() routine used by the lltrace feature (low-level interpreter debugging) robust against recursion by ensuring that it never calls a __repr__ method implemented in Python. Also make the similar output for Tier-2 uops appear on stdout (instead of stderr), to match the lltrace code in ceval.c.

gh-107659 [https://github.com/python/cpython/issues/107659]: Add docstrings for ctypes.pointer() and ctypes.POINTER().

gh-105848 [https://github.com/python/cpython/issues/105848]: Modify the bytecode so that the actual callable for a CALL is at a consistent position on the stack (regardless of whether or not bound-method-calling optimizations are active).

gh-107674 [https://github.com/python/cpython/issues/107674]: Fixed performance regression in sys.settrace.

gh-107724 [https://github.com/python/cpython/issues/107724]: In pre-release versions of 3.12, up to rc1, the sys.monitoring callback function for the PY_THROW event was missing the third, exception argument. That is now fixed.

gh-84436 [https://github.com/python/cpython/issues/84436]: Skip reference count modifications for many known immortal objects.

gh-107596 [https://github.com/python/cpython/issues/107596]: Specialize subscripting str objects by int indexes.

gh-107080 [https://github.com/python/cpython/issues/107080]: Trace refs builds (--with-trace-refs) were crashing when used with isolated subinterpreters. The problematic global state has been isolated to each interpreter. Other fixing the crashes, this change does not affect users.

gh-107557 [https://github.com/python/cpython/issues/107557]: Generate the cases needed for the barebones tier 2 abstract interpreter for optimization passes in CPython.

gh-106608 [https://github.com/python/cpython/issues/106608]: Make _PyUOpExecutorObject variable length.

gh-100964 [https://github.com/python/cpython/issues/100964]: Clear generators’ exception state after return to break reference cycles.

gh-107455 [https://github.com/python/cpython/issues/107455]: Improve error messages when converting an incompatible type to ctypes.c_char_p, ctypes.c_wchar_p and ctypes.c_void_p.

gh-107263 [https://github.com/python/cpython/issues/107263]: Increase C recursion limit for functions other than the main interpreter from 800 to 1500. This should allow functions like list.__repr__ and json.dumps to handle all the inputs that they could prior to 3.12

gh-104584 [https://github.com/python/cpython/issues/104584]: Fix an issue which caused incorrect inline caches to be read when running with PYTHONUOPS or -X uops enabled.

gh-104432 [https://github.com/python/cpython/issues/104432]: Fix potential unaligned memory access on C APIs involving returned sequences of char * pointers within the grp and socket modules. These were revealed using a -fsaniziter=alignment build on ARM macOS. Patch by Christopher Chavez.

gh-106078 [https://github.com/python/cpython/issues/106078]: Isolate _decimal (apply PEP 687 [https://peps.python.org/pep-0687/]). Patch by Charlie Zhao.

gh-106898 [https://github.com/python/cpython/issues/106898]: Add the exception as the third argument to PY_UNIND callbacks in sys.monitoring. This makes the PY_UNWIND callback consistent with the other exception handling callbacks.

gh-106895 [https://github.com/python/cpython/issues/106895]: Raise a ValueError when a monitoring callback function returns DISABLE for events that cannot be disabled locally.

gh-106897 [https://github.com/python/cpython/issues/106897]: Add a RERAISE event to sys.monitoring, which occurs when an exception is reraise, either explicitly by a plain raise statement, or implicitly in an except or finally block.

gh-77377 [https://github.com/python/cpython/issues/77377]: Ensure that multiprocessing synchronization objects created in a fork context are not sent to a different process created in a spawn context. This changes a segfault into an actionable RuntimeError in the parent process.

gh-106931 [https://github.com/python/cpython/issues/106931]: Statically allocated string objects are now interned globally instead of per-interpreter. This fixes a situation where such a string would only be interned in a single interpreter. Normal string objects are unaffected.

gh-104621 [https://github.com/python/cpython/issues/104621]: Unsupported modules now always fail to be imported.

gh-107122 [https://github.com/python/cpython/issues/107122]: Add dbm.ndbm.ndbm.clear() to dbm.ndbm. Patch By Donghee Na.

gh-107122 [https://github.com/python/cpython/issues/107122]: Add dbm.gnu.gdbm.clear() to dbm.gnu. Patch By Donghee Na.

gh-107015 [https://github.com/python/cpython/issues/107015]: The ASYNC and AWAIT tokens are removed from the Grammar, which removes the possibility of making async and await soft keywords when using feature_version<7 in ast.parse().

gh-106917 [https://github.com/python/cpython/issues/106917]: Fix classmethod-style super() method calls (i.e., where the second argument to super(), or the implied second argument drawn from self/cls in the case of zero-arg super, is a type) when the target of the call is not a classmethod.

gh-105699 [https://github.com/python/cpython/issues/105699]: Python no longer crashes due an infrequent race when initializing per-interpreter interned strings. The crash would manifest when the interpreter was finalized.

gh-105699 [https://github.com/python/cpython/issues/105699]: Python no longer crashes due to an infrequent race in setting Py_FileSystemDefaultEncoding and Py_FileSystemDefaultEncodeErrors (both deprecated), when simultaneously initializing two isolated subinterpreters. Now they are only set during runtime initialization.

gh-106908 [https://github.com/python/cpython/issues/106908]: Fix various hangs, reference leaks, test failures, and tracing/introspection bugs when running with PYTHONUOPS or -X uops enabled.

gh-106092 [https://github.com/python/cpython/issues/106092]: Fix a segmentation fault caused by a use-after-free bug in frame_dealloc when the trashcan delays the deallocation of a PyFrameObject.

gh-106485 [https://github.com/python/cpython/issues/106485]: Reduce the number of materialized instances dictionaries by dematerializing them when possible.

gh-106719 [https://github.com/python/cpython/issues/106719]: No longer suppress arbitrary errors in the __annotations__ getter and setter in the type and module types.

gh-106723 [https://github.com/python/cpython/issues/106723]: Propagate frozen_modules to multiprocessing spawned process interpreters.

gh-104909 [https://github.com/python/cpython/issues/104909]: Split LOAD_ATTR_INSTANCE_VALUE into micro-ops.

gh-104909 [https://github.com/python/cpython/issues/104909]: Split LOAD_GLOBAL specializations into micro-ops.

gh-106597 [https://github.com/python/cpython/issues/106597]: A new debug structure of offsets has been added to the _PyRuntimeState that will help out-of-process debuggers and profilers to obtain the offsets to relevant interpreter structures in a way that is agnostic of how Python was compiled and that doesn’t require copying the headers. Patch by Pablo Galindo

gh-106487 [https://github.com/python/cpython/issues/106487]: Allow the count argument of str.replace() to be a keyword. Patch by Hugo van Kemenade.

gh-96844 [https://github.com/python/cpython/issues/96844]: Improve error message of list.remove(). Patch by Donghee Na.

gh-81283 [https://github.com/python/cpython/issues/81283]: Compiler now strips indents from docstrings. It reduces pyc file size 5% when the module is heavily documented. This change affects to __doc__ so tools like doctest will be affected.

gh-106396 [https://github.com/python/cpython/issues/106396]: When the format specification of an f-string expression is empty, the parser now generates an empty ast.JoinedStr node for it instead of an one-element ast.JoinedStr with an empty string ast.Constant.

gh-100288 [https://github.com/python/cpython/issues/100288]: Specialize LOAD_ATTR for non-descriptors on the class. Adds LOAD_ATTR_NONDESCRIPTOR_WITH_VALUES and LOAD_ATTR_NONDESCRIPTOR_NO_DICT.

gh-106008 [https://github.com/python/cpython/issues/106008]: Fix possible reference leaks when failing to optimize comparisons with None in the bytecode compiler.

gh-106145 [https://github.com/python/cpython/issues/106145]: Make end_lineno and end_col_offset required on type_param ast nodes.

gh-106213 [https://github.com/python/cpython/issues/106213]: Changed the way that Emscripten call trampolines work for compatibility with Wasm/JS Promise integration.

gh-106182 [https://github.com/python/cpython/issues/106182]: sys.getfilesystemencoding() and sys.getfilesystemencodeerrors now return interned Unicode object.

gh-106210 [https://github.com/python/cpython/issues/106210]: Removed Emscripten import trampoline as it was no longer necessary for Pyodide.

gh-104584 [https://github.com/python/cpython/issues/104584]: Added a new, experimental, tracing optimizer and interpreter (a.k.a. “tier 2”). This currently pessimizes, so don’t use yet – this is infrastructure so we can experiment with optimizing passes. To enable it, pass -Xuops or set PYTHONUOPS=1. To get debug output, set PYTHONUOPSDEBUG=N where N is a debug level (0-4, where 0 is no debug output and 4 is excessively verbose).

gh-105775 [https://github.com/python/cpython/issues/105775]: LOAD_CLOSURE is now a pseudo-op.

gh-105730 [https://github.com/python/cpython/issues/105730]: Allow any callable other than type objects as the condition predicate in BaseExceptionGroup.split() and BaseExceptionGroup.subgroup().

gh-105979 [https://github.com/python/cpython/issues/105979]: Fix crash in _imp.get_frozen_object() due to improper exception handling.

gh-106003 [https://github.com/python/cpython/issues/106003]: Add a new TO_BOOL instruction, which performs boolean conversions for POP_JUMP_IF_TRUE, POP_JUMP_IF_FALSE, and UNARY_NOT (which all expect exact bool values now). Also, modify the oparg of COMPARE_OP to include an optional “boolean conversion” flag.

gh-98931 [https://github.com/python/cpython/issues/98931]: Ensure custom SyntaxError error messages are raised for invalid imports with multiple targets. Patch by Pablo Galindo

gh-105724 [https://github.com/python/cpython/issues/105724]: Improve assert error messages by providing exact error range.

gh-105908 [https://github.com/python/cpython/issues/105908]: Fixed bug where gh-99111 [https://github.com/python/cpython/issues/99111] breaks future import barry_as_FLUFL in the Python REPL.

gh-105840 [https://github.com/python/cpython/issues/105840]: Fix possible crashes when specializing function calls with too many __defaults__.

gh-105831 [https://github.com/python/cpython/issues/105831]: Fix an f-string bug, where using a debug expression (the = sign) that appears in the last line of a file results to the debug buffer that holds the expression text being one character too small.

gh-105800 [https://github.com/python/cpython/issues/105800]: Correctly issue SyntaxWarning in f-strings if invalid sequences are used. Patch by Pablo Galindo

gh-105340 [https://github.com/python/cpython/issues/105340]: Include the comprehension iteration variable in locals() inside a module- or class-scope comprehension.

gh-105331 [https://github.com/python/cpython/issues/105331]: Raise ValueError if the delay argument to asyncio.sleep() is a NaN (matching time.sleep()).

gh-105587 [https://github.com/python/cpython/issues/105587]: The runtime can’t guarantee that immortal objects will not be mutated by Extensions. Thus, this modifies _PyStaticObject_CheckRefcnt to warn instead of asserting.

gh-105564 [https://github.com/python/cpython/issues/105564]: Don’t include artificil newlines in the line attribute of tokens in the APIs of the tokenize module. Patch by Pablo Galindo

gh-105549 [https://github.com/python/cpython/issues/105549]: Tokenize separately NUMBER and NAME tokens that are not ambiguous. Patch by Pablo Galindo.

gh-105588 [https://github.com/python/cpython/issues/105588]: Fix an issue that could result in crashes when compiling malformed ast nodes.

gh-100987 [https://github.com/python/cpython/issues/100987]: Allow objects other than code objects as the “executable” in internal frames. In the long term, this can help tools like Cython and PySpy interact more efficiently. In the shorter term, it allows us to perform some optimizations more simply.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in the builtins module where exceptions could end up being overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bug in the compiler where an exception could end up being overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Improve error handling in PyUnicode_BuildEncodingMap() where an exception could end up being overwritten.

gh-105486 [https://github.com/python/cpython/issues/105486]: Change the repr of ParamSpec list of args in types.GenericAlias.

gh-105678 [https://github.com/python/cpython/issues/105678]: Break the MAKE_FUNCTION instruction into two parts, MAKE_FUNCTION which makes the function and SET_FUNCTION_ATTRIBUTE which sets the attributes on the function. This makes the stack effect of MAKE_FUNCTION regular to ease optimization and code generation.

gh-105435 [https://github.com/python/cpython/issues/105435]: Fix spurious newline character if file ends on a comment without a newline. Patch by Pablo Galindo

gh-105390 [https://github.com/python/cpython/issues/105390]: Correctly raise tokenize.TokenError exceptions instead of SyntaxError for tokenize errors such as incomplete input. Patch by Pablo Galindo

gh-105259 [https://github.com/python/cpython/issues/105259]: Don’t include newline character for trailing NEWLINE tokens emitted in the tokenize module. Patch by Pablo Galindo

gh-104635 [https://github.com/python/cpython/issues/104635]: Eliminate redundant STORE_FAST instructions in the compiler. Patch by Donghee Na and Carl Meyer.

gh-105324 [https://github.com/python/cpython/issues/105324]: Fix the main function of the tokenize module when reading from sys.stdin. Patch by Pablo Galindo

gh-33092 [https://github.com/python/cpython/issues/33092]: Simplify and speed up interpreter for f-strings. Removes FORMAT_VALUE opcode. Add CONVERT_VALUE, FORMAT_SIMPLE and FORMAT_WITH_SPEC opcode. Compiler emits more efficient sequence for each format expression.

gh-105229 [https://github.com/python/cpython/issues/105229]: Remove remaining two-codeunit superinstructions. All remaining superinstructions only take a single codeunit, simplifying instrumentation and quickening.

gh-105235 [https://github.com/python/cpython/issues/105235]: Prevent out-of-bounds memory access during mmap.find() calls.

gh-98963 [https://github.com/python/cpython/issues/98963]: Restore the ability for a subclass of property to define __slots__ or otherwise be dict-less by ignoring failures to set a docstring on such a class. This behavior had regressed in 3.12beta1. An AttributeError where there had not previously been one was disruptive to existing code.

gh-104812 [https://github.com/python/cpython/issues/104812]: The “pending call” machinery now works for all interpreters, not just the main interpreter, and runs in all threads, not just the main thread. Some calls are still only done in the main thread, ergo in the main interpreter. This change does not affect signal handling nor the existing public C-API (Py_AddPendingCall()), which both still only target the main thread. The new functionality is meant strictly for internal use for now, since consequences of its use are not well understood yet outside some very restricted cases. This change brings the capability in line with the intention when the state was made per-interpreter several years ago.

gh-105194 [https://github.com/python/cpython/issues/105194]: Do not escape with backslashes f-string format specifiers. Patch by Pablo Galindo

gh-105229 [https://github.com/python/cpython/issues/105229]: Replace some dynamic superinstructions with single instruction equivalents.

gh-105162 [https://github.com/python/cpython/issues/105162]: Fixed bug in generator.close()/throw() where an inner iterator would be ignored when the outer iterator was instrumented.

gh-105164 [https://github.com/python/cpython/issues/105164]: Ensure annotations are set up correctly if the only annotation in a block is within a match block. Patch by Jelle Zijlstra.

gh-105148 [https://github.com/python/cpython/issues/105148]: Make _PyASTOptimizeState internal to ast_opt.c. Make _PyAST_Optimize take two integers instead of a pointer to this struct. This avoids the need to include pycore_compile.h in ast_opt.c.

gh-104799 [https://github.com/python/cpython/issues/104799]: Attributes of ast nodes that are lists now default to the empty list if omitted. This means that some code that previously raised TypeError when the AST node was used will now proceed with the empty list instead. Patch by Jelle Zijlstra.

gh-105111 [https://github.com/python/cpython/issues/105111]: Remove the old trashcan macros Py_TRASHCAN_SAFE_BEGIN and Py_TRASHCAN_SAFE_END. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END.

gh-105035 [https://github.com/python/cpython/issues/105035]: Fix super() calls on types with custom tp_getattro implementation (e.g. meta-types.)

gh-105017 [https://github.com/python/cpython/issues/105017]: Show CRLF lines in the tokenize string attribute in both NL and NEWLINE tokens. Patch by Marta Gómez.

gh-105013 [https://github.com/python/cpython/issues/105013]: Fix handling of multiline parenthesized lambdas in inspect.getsource(). Patch by Pablo Galindo

gh-105017 [https://github.com/python/cpython/issues/105017]: Do not include an additional final NL token when parsing files having CRLF lines. Patch by Marta Gómez.

gh-104976 [https://github.com/python/cpython/issues/104976]: Ensure that trailing DEDENT tokenize.TokenInfo objects emitted by the tokenize module are reported as in Python 3.11. Patch by Pablo Galindo

gh-104972 [https://github.com/python/cpython/issues/104972]: Ensure that the line attribute in tokenize.TokenInfo objects in the tokenize module are always correct. Patch by Pablo Galindo

gh-104955 [https://github.com/python/cpython/issues/104955]: Fix signature for the new __release_buffer__() slot. Patch by Jelle Zijlstra.

gh-104690 [https://github.com/python/cpython/issues/104690]: Starting new threads and process creation through os.fork() during interpreter shutdown (such as from atexit handlers) is no longer supported. It can lead to race condition between the main Python runtime thread freeing thread states while internal threading routines are trying to allocate and use the state of just created threads. Or forked children trying to use the mid-shutdown runtime and thread state in the child process.

gh-104879 [https://github.com/python/cpython/issues/104879]: Fix crash when accessing the __module__ attribute of type aliases defined outside a module. Patch by Jelle Zijlstra.

gh-104825 [https://github.com/python/cpython/issues/104825]: Tokens emitted by the tokenize module do not include an implicit \n character in the line attribute anymore. Patch by Pablo Galindo

gh-104770 [https://github.com/python/cpython/issues/104770]: If a generator returns a value upon being closed, the value is now returned by generator.close().

gh-89091 [https://github.com/python/cpython/issues/89091]: Raise RuntimeWarning for unawaited async generator methods like asend(), athrow() and aclose(). Patch by Kumar Aditya.

gh-96663 [https://github.com/python/cpython/issues/96663]: Add a better, more introspect-able error message when setting attributes on classes without a __dict__ and no slot member for the attribute.

gh-93627 [https://github.com/python/cpython/issues/93627]: Update the Python pickle module implementation to match the C implementation of the pickle module. For objects setting reduction methods like __reduce_ex__() or __reduce__() to None, pickling will result in a TypeError.

gh-101006 [https://github.com/python/cpython/issues/101006]: Improve error handling when read marshal data.

gh-91095 [https://github.com/python/cpython/issues/91095]: Specializes calls to most Python classes. Specifically, any class that inherits from object, or another Python class, and does not override __new__.

The specialized instruction does the following:

Creates the object (by calling object.__new__)

Pushes a shim frame to the frame stack (to cleanup after __init__)

Pushes the frame for __init__ to the frame stack

Speeds up the instantiation of most Python classes.

Library

gh-110786 [https://github.com/python/cpython/issues/110786]: sysconfig’s CLI now ignores BrokenPipeError, making it exit normally if its output is being piped and the pipe closes.

gh-103480 [https://github.com/python/cpython/issues/103480]: The sysconfig module is now a package, instead of a single-file module.

gh-110733 [https://github.com/python/cpython/issues/110733]: Micro-optimization: Avoid calling min(), max() in BaseEventLoop._run_once().

gh-94597 [https://github.com/python/cpython/issues/94597]: Added asyncio.EventLoop for use with the asyncio.run() loop_factory kwarg to avoid calling the asyncio policy system.

gh-110682 [https://github.com/python/cpython/issues/110682]: runtime-checkable protocols used to consider __match_args__ a protocol member in __instancecheck__ if it was present on the protocol. Now, this attribute is ignored if it is present.

gh-110488 [https://github.com/python/cpython/issues/110488]: Fix a couple of issues in pathlib.PurePath.with_name(): a single dot was incorrectly considered a valid name, and in PureWindowsPath, a name with an NTFS alternate data stream, like a:b, was incorrectly considered invalid.

gh-110590 [https://github.com/python/cpython/issues/110590]: Fix a bug in _sre.compile() where TypeError would be overwritten by OverflowError when the code argument was a list of non-ints.

gh-65052 [https://github.com/python/cpython/issues/65052]: Prevent pdb from crashing when trying to display undisplayable objects

gh-110519 [https://github.com/python/cpython/issues/110519]: Deprecation warning about non-integer number in gettext now always refers to the line in the user code where gettext function or method is used. Previously it could refer to a line in gettext code.

gh-89902 [https://github.com/python/cpython/issues/89902]: Deprecate non-standard format specifier “N” for decimal.Decimal. It was not documented and only supported in the C implementation.

gh-110378 [https://github.com/python/cpython/issues/110378]: contextmanager() and asynccontextmanager() context managers now close an invalid underlying generator object that yields more then one value.

gh-106670 [https://github.com/python/cpython/issues/106670]: In pdb, set convenience variable $_exception for post mortem debugging.

gh-110365 [https://github.com/python/cpython/issues/110365]: Fix termios.tcsetattr() bug that was overwriting existing errors during parsing integers from term list.

gh-109653 [https://github.com/python/cpython/issues/109653]: Slightly improve the import time of several standard-library modules by deferring imports of warnings within those modules. Patch by Alex Waygood.

gh-110273 [https://github.com/python/cpython/issues/110273]: dataclasses.replace() now raises TypeError instead of ValueError if specify keyword argument for a field declared with init=False or miss keyword argument for required InitVar field.

gh-110249 [https://github.com/python/cpython/issues/110249]: Add --inline-caches flag to dis command line.

gh-109653 [https://github.com/python/cpython/issues/109653]: Fix a Python 3.12 regression in the import time of random. Patch by Alex Waygood.

gh-110222 [https://github.com/python/cpython/issues/110222]: Add support of struct sequence objects in copy.replace(). Patched by Xuehai Pan.

gh-109649 [https://github.com/python/cpython/issues/109649]: multiprocessing, concurrent.futures, compileall: Replace os.cpu_count() with os.process_cpu_count() to select the default number of worker threads and processes. Get the CPU affinity if supported. Patch by Victor Stinner.

gh-110150 [https://github.com/python/cpython/issues/110150]: Fix base case handling in statistics.quantiles. Now allows a single data point.

gh-110036 [https://github.com/python/cpython/issues/110036]: On Windows, multiprocessing Popen.terminate() now catches PermissionError and get the process exit code. If the process is still running, raise again the PermissionError. Otherwise, the process terminated as expected: store its exit code. Patch by Victor Stinner.

gh-110038 [https://github.com/python/cpython/issues/110038]: Fixed an issue that caused KqueueSelector.select() to not return all the ready events in some cases when a file descriptor is registered for both read and write.

gh-110045 [https://github.com/python/cpython/issues/110045]: Update the symtable module to support the new scopes introduced by PEP 695 [https://peps.python.org/pep-0695/].

gh-88402 [https://github.com/python/cpython/issues/88402]: Add new variables to sysconfig.get_config_vars() on Windows: LIBRARY, LDLIBRARY, LIBDIR, SOABI, and Py_NOGIL.

gh-109631 [https://github.com/python/cpython/issues/109631]: re functions such as re.findall(), re.split(), re.search() and re.sub() which perform short repeated matches can now be interrupted by user.

gh-109653 [https://github.com/python/cpython/issues/109653]: Reduce the import time of email.utils by around 43%. This results in the import time of email.message falling by around 18%, which in turn reduces the import time of importlib.metadata by around 6%. Patch by Alex Waygood.

gh-109818 [https://github.com/python/cpython/issues/109818]: Fix reprlib.recursive_repr() not copying __type_params__ from decorated function.

gh-109047 [https://github.com/python/cpython/issues/109047]: concurrent.futures: The executor manager thread now catches exceptions when adding an item to the call queue. During Python finalization, creating a new thread can now raise RuntimeError. Catch the exception and call terminate_broken() in this case. Patch by Victor Stinner.

gh-109782 [https://github.com/python/cpython/issues/109782]: Ensure the signature of os.path.isdir() is identical on all platforms. Patch by Amin Alaee.

gh-109653 [https://github.com/python/cpython/issues/109653]: Improve import time of functools by around 13%. Patch by Alex Waygood.

gh-109590 [https://github.com/python/cpython/issues/109590]: shutil.which() will prefer files with an extension in PATHEXT if the given mode includes os.X_OK on win32. If no PATHEXT match is found, a file without an extension in PATHEXT can be returned. This change will have shutil.which() act more similarly to previous behavior in Python 3.11.

gh-109653 [https://github.com/python/cpython/issues/109653]: Reduce the import time of enum by over 50%. Patch by Alex Waygood.

gh-109593 [https://github.com/python/cpython/issues/109593]: Avoid deadlocking on a reentrant call to the multiprocessing resource tracker. Such a reentrant call, though unlikely, can happen if a GC pass invokes the finalizer for a multiprocessing object such as SemLock.

gh-109653 [https://github.com/python/cpython/issues/109653]: Reduce the import time of typing by around a third. Patch by Alex Waygood.

gh-109649 [https://github.com/python/cpython/issues/109649]: Add os.process_cpu_count() function to get the number of logical CPUs usable by the calling thread of the current process. Patch by Victor Stinner.

gh-74481 [https://github.com/python/cpython/issues/74481]: Add set_error_mode related constants in msvcrt module in Python debug build.

gh-109613 [https://github.com/python/cpython/issues/109613]: Fix os.stat() and os.DirEntry.stat(): check for exceptions. Previously, on Python built in debug mode, these functions could trigger a fatal Python error (and abort the process) when a function succeeded with an exception set. Patch by Victor Stinner.

gh-109599 [https://github.com/python/cpython/issues/109599]: Expose the type of PyCapsule objects as types.CapsuleType.

gh-109109 [https://github.com/python/cpython/issues/109109]: You can now get the raw TLS certificate chains from TLS connections via ssl.SSLSocket.get_verified_chain() and ssl.SSLSocket.get_unverified_chain() methods.

Contributed by Mateusz Nowak.

gh-109559 [https://github.com/python/cpython/issues/109559]: Update unicodedata database to Unicode 15.1.0.

gh-109543 [https://github.com/python/cpython/issues/109543]: Remove unnecessary hasattr() check during typing.TypedDict creation.

gh-109495 [https://github.com/python/cpython/issues/109495]: Remove unnecessary extra __slots__ in datetime's pure python implementation to reduce memory size, as they are defined in the superclass. Patch by James Hilton-Balfe

gh-109461 [https://github.com/python/cpython/issues/109461]: logging: Use a context manager for lock acquisition.

gh-109096 [https://github.com/python/cpython/issues/109096]: http.server.CGIHTTPRequestHandler has been deprecated for removal in 3.15. Its design is old and the web world has long since moved beyond CGI.

gh-109409 [https://github.com/python/cpython/issues/109409]: Fix error when it was possible to inherit a frozen dataclass from multiple parents some of which were possibly not frozen.

gh-109375 [https://github.com/python/cpython/issues/109375]: The pdb alias command now prevents registering aliases without arguments.

gh-109319 [https://github.com/python/cpython/issues/109319]: Deprecate the dis.HAVE_ARGUMENT field in favour of dis.hasarg.

gh-107219 [https://github.com/python/cpython/issues/107219]: Fix a race condition in concurrent.futures. When a process in the process pool was terminated abruptly (while the future was running or pending), close the connection write end. If the call queue is blocked on sending bytes to a worker process, closing the connection write end interrupts the send, so the queue can be closed. Patch by Victor Stinner.

gh-66143 [https://github.com/python/cpython/issues/66143]: The codecs.CodecInfo object has been made copyable and pickleable. Patched by Robert Lehmann and Furkan Onder.

gh-109187 [https://github.com/python/cpython/issues/109187]: pathlib.Path.resolve() now treats symlink loops like other errors: in strict mode, OSError is raised, and in non-strict mode, no exception is raised.

gh-50644 [https://github.com/python/cpython/issues/50644]: Attempts to pickle or create a shallow or deep copy of codecs streams now raise a TypeError. Previously, copying failed with a RecursionError, while pickling produced wrong results that eventually caused unpickling to fail with a RecursionError.

gh-109174 [https://github.com/python/cpython/issues/109174]: Add support of types.SimpleNamespace in copy.replace().

gh-109164 [https://github.com/python/cpython/issues/109164]: pdb: Replace getopt with argparse for parsing command line arguments.

gh-109151 [https://github.com/python/cpython/issues/109151]: Enable readline editing features in the sqlite3 command-line interface (python -m sqlite3).

gh-108987 [https://github.com/python/cpython/issues/108987]: Fix _thread.start_new_thread() race condition. If a thread is created during Python finalization, the newly spawned thread now exits immediately instead of trying to access freed memory and lead to a crash. Patch by Victor Stinner.

gh-108682 [https://github.com/python/cpython/issues/108682]: Enum: require names=() or type=... to create an empty enum using the functional syntax.

gh-109033 [https://github.com/python/cpython/issues/109033]: Exceptions raised by os.utime builtin function now include the related filename

gh-108843 [https://github.com/python/cpython/issues/108843]: Fix an issue in ast.unparse() when unparsing f-strings containing many quote types.

gh-108469 [https://github.com/python/cpython/issues/108469]: ast.unparse() now supports new f-string syntax introduced in Python 3.12. Note that the f-string quotes are reselected for simplicity under the new syntax. (Patch by Steven Sun)

gh-108751 [https://github.com/python/cpython/issues/108751]: Add copy.replace() function which allows to create a modified copy of an object. It supports named tuples, dataclasses, and many other objects.

gh-108682 [https://github.com/python/cpython/issues/108682]: Enum: raise TypeError if super().__new__() is called from a custom __new__.

gh-108278 [https://github.com/python/cpython/issues/108278]: Deprecate passing the callback callable by keyword for the following sqlite3.Connection APIs:

set_authorizer()

set_progress_handler()

set_trace_callback()

The affected parameters will become positional-only in Python 3.15.

Patch by Erlend E. Aasland.

gh-105829 [https://github.com/python/cpython/issues/105829]: Fix concurrent.futures.ProcessPoolExecutor deadlock

gh-108295 [https://github.com/python/cpython/issues/108295]: Fix crashes related to use of weakrefs on typing.TypeVar.

gh-108463 [https://github.com/python/cpython/issues/108463]: Make expressions/statements work as expected in pdb

gh-108277 [https://github.com/python/cpython/issues/108277]: Add os.timerfd_create(), os.timerfd_settime(), os.timerfd_gettime(), os.timerfd_settime_ns(), and os.timerfd_gettime_ns() to provide a low level interface for Linux’s timer notification file descriptor.

gh-107811 [https://github.com/python/cpython/issues/107811]: tarfile: extraction of members with overly large UID or GID (e.g. on an OS with 32-bit id_t) now fails in the same way as failing to set the ID.

gh-64662 [https://github.com/python/cpython/issues/64662]: Fix support for virtual tables in sqlite3.Connection.iterdump(). Patch by Aviv Palivoda.

gh-108111 [https://github.com/python/cpython/issues/108111]: Fix a regression introduced in gh-101251 [https://github.com/python/cpython/issues/101251] for 3.12, resulting in an incorrect offset calculation in gzip.GzipFile.seek().

gh-108294 [https://github.com/python/cpython/issues/108294]: time.sleep() now raises an auditing event.

gh-108278 [https://github.com/python/cpython/issues/108278]: Deprecate passing name, number of arguments, and the callable as keyword arguments, for the following sqlite3.Connection APIs:

create_function()

create_aggregate()

The affected parameters will become positional-only in Python 3.15.

Patch by Erlend E. Aasland.

gh-108322 [https://github.com/python/cpython/issues/108322]: Speed-up NormalDist.samples() by using the inverse CDF method instead of calling random.gauss().

gh-83417 [https://github.com/python/cpython/issues/83417]: Add the ability for venv to create a .gitignore file which causes the created environment to be ignored by Git. It is on by default when venv is called via its CLI.

gh-105736 [https://github.com/python/cpython/issues/105736]: Harmonized the pure Python version of OrderedDict with the C version. Now, both versions set up their internal state in __new__. Formerly, the pure Python version did the set up in __init__.

gh-108083 [https://github.com/python/cpython/issues/108083]: Fix bugs in the constructor of sqlite3.Connection and sqlite3.Connection.close() where exceptions could be leaked. Patch by Erlend E. Aasland.

gh-107932 [https://github.com/python/cpython/issues/107932]: Fix dis module to properly report and display bytecode that do not have source lines.

gh-105539 [https://github.com/python/cpython/issues/105539]: sqlite3 now emits an ResourceWarning if a sqlite3.Connection object is not closed explicitly. Patch by Erlend E. Aasland.

gh-107995 [https://github.com/python/cpython/issues/107995]: The __module__ attribute on instances of functools.cached_property is now set to the name of the module in which the cached_property is defined, rather than “functools”. This means that doctests in cached_property docstrings are now properly collected by the doctest module. Patch by Tyler Smart.

gh-107963 [https://github.com/python/cpython/issues/107963]: Fix multiprocessing.set_forkserver_preload() to check the given list of modules names. Patch by Donghee Na.

gh-106242 [https://github.com/python/cpython/issues/106242]: Fixes os.path.normpath() to handle embedded null characters without truncating the path.

gh-81555 [https://github.com/python/cpython/issues/81555]: xml.dom.minidom now only quotes " in attributes.

gh-50002 [https://github.com/python/cpython/issues/50002]: xml.dom.minidom now preserves whitespaces in attributes.

gh-93057 [https://github.com/python/cpython/issues/93057]: Passing more than one positional argument to sqlite3.connect() and the sqlite3.Connection constructor is deprecated. The remaining parameters will become keyword-only in Python 3.15. Patch by Erlend E. Aasland.

gh-76913 [https://github.com/python/cpython/issues/76913]: Add merge_extra parameter/feature to logging.LoggerAdapter

gh-107913 [https://github.com/python/cpython/issues/107913]: Fix possible losses of errno and winerror values in OSError exceptions if they were cleared or modified by the cleanup code before creating the exception object.

gh-107845 [https://github.com/python/cpython/issues/107845]: tarfile.data_filter() now takes the location of symlinks into account when determining their target, so it will no longer reject some valid tarballs with LinkOutsideDestinationError.

gh-107812 [https://github.com/python/cpython/issues/107812]: Extend socket’s netlink support to the FreeBSD platform.

gh-107805 [https://github.com/python/cpython/issues/107805]: Fix signatures of module-level generated functions in turtle.

gh-107782 [https://github.com/python/cpython/issues/107782]: pydoc is now able to show signatures which are not representable in Python, e.g. for getattr and dict.pop.

gh-56166 [https://github.com/python/cpython/issues/56166]: Deprecate passing optional arguments maxsplit, count and flags in module-level functions re.split(), re.sub() and re.subn() as positional. They should only be passed by keyword.

gh-107710 [https://github.com/python/cpython/issues/107710]: Speed up logging.getHandlerNames().

gh-107715 [https://github.com/python/cpython/issues/107715]: Fix doctest.DocTestFinder.find() in presence of class names with special characters. Patch by Gertjan van Zwieten.

gh-100814 [https://github.com/python/cpython/issues/100814]: Passing a callable object as an option value to a Tkinter image now raises the expected TclError instead of an AttributeError.

gh-72684 [https://github.com/python/cpython/issues/72684]: Add tkinter widget methods: tk_busy_hold(), tk_busy_configure(), tk_busy_cget(), tk_busy_forget(), tk_busy_current(), and tk_busy_status().

gh-106684 [https://github.com/python/cpython/issues/106684]: Raise ResourceWarning when asyncio.StreamWriter is not closed leading to memory leaks. Patch by Kumar Aditya.

gh-107465 [https://github.com/python/cpython/issues/107465]: Add pathlib.Path.from_uri() classmethod.

gh-107077 [https://github.com/python/cpython/issues/107077]: Seems that in some conditions, OpenSSL will return SSL_ERROR_SYSCALL instead of SSL_ERROR_SSL when a certification verification has failed, but the error parameters will still contain ERR_LIB_SSL and SSL_R_CERTIFICATE_VERIFY_FAILED. We are now detecting this situation and raising the appropriate ssl.SSLCertVerificationError. Patch by Pablo Galindo

gh-107576 [https://github.com/python/cpython/issues/107576]: Fix types.get_original_bases() to only return __orig_bases__ if it is present on cls directly. Patch by James Hilton-Balfe.

gh-105481 [https://github.com/python/cpython/issues/105481]: Remove opcode.is_pseudo, opcode.MIN_PSEUDO_OPCODE and opcode.MAX_PSEUDO_OPCODE, which were added in 3.12, were never documented and were not intended to be used externally.

gh-105481 [https://github.com/python/cpython/issues/105481]: opcode.ENABLE_SPECIALIZATION (which was added in 3.12 but never documented or intended for external usage) is moved to _opcode.ENABLE_SPECIALIZATION where tests can access it.

gh-107396 [https://github.com/python/cpython/issues/107396]: tarfiles; Fixed use before assignment of self.exception for gzip decompression

gh-107409 [https://github.com/python/cpython/issues/107409]: Set __wrapped__ attribute in reprlib.recursive_repr().

gh-107406 [https://github.com/python/cpython/issues/107406]: Implement new __repr__() method for struct.Struct. Now it returns Struct(<format repr>).

gh-107369 [https://github.com/python/cpython/issues/107369]: Optimize textwrap.indent(). It is ~30% faster for large input. Patch by Inada Naoki.

gh-78722 [https://github.com/python/cpython/issues/78722]: Fix issue where pathlib.Path.iterdir() did not raise OSError until iterated.

gh-105578 [https://github.com/python/cpython/issues/105578]: Deprecate typing.AnyStr in favor of the new Type Parameter syntax. See PEP 695.

gh-62519 [https://github.com/python/cpython/issues/62519]: Make gettext.pgettext() search plural definitions when translation is not found.

gh-107089 [https://github.com/python/cpython/issues/107089]: Shelves opened with shelve.open() have a much faster clear() method. Patch by James Cave.

gh-82500 [https://github.com/python/cpython/issues/82500]: Fix overflow on 32-bit systems with asyncio os.sendfile() implementation.

gh-83006 [https://github.com/python/cpython/issues/83006]: Document behavior of shutil.disk_usage() for non-mounted filesystems on Unix.

gh-65495 [https://github.com/python/cpython/issues/65495]: Use lowercase mail from and rcpt to in smptlib.SMTP.

gh-106186 [https://github.com/python/cpython/issues/106186]: Do not report MultipartInvariantViolationDefect defect when the email.parser.Parser class is used to parse emails with headersonly=True.

gh-105002 [https://github.com/python/cpython/issues/105002]: Fix invalid result from PurePath.relative_to() method when attempting to walk a “..” segment in other with walk_up enabled. A ValueError exception is now raised in this case.

gh-106739 [https://github.com/python/cpython/issues/106739]: Add the rtype_cache to the warning message (as an addition to the type of leaked objects and the number of leaked objects already included in the message) to make debugging leaked objects easier when the multiprocessing resource tracker process finds leaked objects at shutdown. This helps more quickly identify what was leaked and/or why the leaked object was not properly cleaned up.

gh-106751 [https://github.com/python/cpython/issues/106751]: Optimize SelectSelector.select() for many iteration case. Patch By Donghee Na.

gh-106751 [https://github.com/python/cpython/issues/106751]: Optimize _PollLikeSelector.select() for many iteration case.

gh-106751 [https://github.com/python/cpython/issues/106751]: Optimize KqueueSelector.select() for many iteration case. Patch By Donghee Na.

gh-106831 [https://github.com/python/cpython/issues/106831]: Fix potential missing NULL check of d2i_SSL_SESSION result in _ssl.c.

gh-105481 [https://github.com/python/cpython/issues/105481]: The various opcode lists in the dis module are now generated from bytecodes.c instead of explicitly constructed in opcode.py.

gh-106727 [https://github.com/python/cpython/issues/106727]: Make inspect.getsource() smarter for class for same name definitions

gh-106789 [https://github.com/python/cpython/issues/106789]: Remove import of pprint from sysconfig.

gh-105726 [https://github.com/python/cpython/issues/105726]: Added __slots__ to contextlib.AbstractContextManager and contextlib.AbstractAsyncContextManager so that child classes can use __slots__.

gh-106774 [https://github.com/python/cpython/issues/106774]: Update the bundled copy of pip to version 23.2.1.

gh-106751 [https://github.com/python/cpython/issues/106751]: selectors: Optimize EpollSelector.select() code by moving some code outside of the loop.

gh-106752 [https://github.com/python/cpython/issues/106752]: Fixed several bugs in zipfile.Path, including: in zipfile.Path.match(), Windows separators are no longer honored (and never were meant to be); Fixed name/suffix/suffixes/stem operations when no filename is present and the Path is not at the root of the zipfile; Reworked glob for performance and more correct matching behavior.

gh-105293 [https://github.com/python/cpython/issues/105293]: Remove call to SSL_CTX_set_session_id_context during client side context creation in the ssl module.

gh-106734 [https://github.com/python/cpython/issues/106734]: Disable tab completion in multiline mode of pdb

gh-105481 [https://github.com/python/cpython/issues/105481]: Expose opcode metadata through _opcode.

gh-106670 [https://github.com/python/cpython/issues/106670]: Add the new exceptions command to the Pdb debugger. It makes it possible to move between chained exceptions when using post mortem debugging.

gh-106602 [https://github.com/python/cpython/issues/106602]: Add __copy__ and __deepcopy__ in enum

gh-106664 [https://github.com/python/cpython/issues/106664]: selectors: Add _SelectorMapping.get() method and optimize _SelectorMapping.__getitem__().

gh-106628 [https://github.com/python/cpython/issues/106628]: Speed up parsing of emails by about 20% by not compiling a new regular expression for every single email.

gh-89427 [https://github.com/python/cpython/issues/89427]: Set the environment variable VIRTUAL_ENV_PROMPT at venv activation, even when VIRTUAL_ENV_DISABLE_PROMPT is set.

gh-106530 [https://github.com/python/cpython/issues/106530]: Revert a change to colorsys.rgb_to_hls() that caused division by zero for certain almost-white inputs. Patch by Terry Jan Reedy.

gh-106584 [https://github.com/python/cpython/issues/106584]: Fix exit code for unittest if all tests are skipped. Patch by Egor Eliseev.

gh-106566 [https://github.com/python/cpython/issues/106566]: Optimize (?!) (pattern which always fails) in regular expressions.

gh-106554 [https://github.com/python/cpython/issues/106554]: selectors: Reduce Selector overhead by using a dict.get() to lookup file descriptors.

gh-106558 [https://github.com/python/cpython/issues/106558]: Remove ref cycle in callers of convert_to_error() by deleting result from scope in a finally block.

gh-100502 [https://github.com/python/cpython/issues/100502]: Add pathlib.PurePath.pathmod class attribute that stores the implementation of os.path used for low-level path operations: either posixpath or ntpath.

gh-106527 [https://github.com/python/cpython/issues/106527]: Reduce overhead to add and remove asyncio readers and writers.

gh-106524 [https://github.com/python/cpython/issues/106524]: Fix crash in _sre.template() with templates containing invalid group indices.

gh-106531 [https://github.com/python/cpython/issues/106531]: Removed _legacy and the names it provided from importlib.resources: Resource, contents, is_resource, open_binary, open_text, path, read_binary, and read_text.

gh-106052 [https://github.com/python/cpython/issues/106052]: re module: fix the matching of possessive quantifiers in the case of a subpattern containing backtracking.

gh-106510 [https://github.com/python/cpython/issues/106510]: Improve debug output for atomic groups in regular expressions.

gh-106503 [https://github.com/python/cpython/issues/106503]: Fix ref cycle in asyncio._SelectorSocketTransport by removing _write_ready in close.

gh-105497 [https://github.com/python/cpython/issues/105497]: Fix flag mask inversion when unnamed flags exist.

gh-90876 [https://github.com/python/cpython/issues/90876]: Prevent multiprocessing.spawn from failing to import in environments where sys.executable is None. This regressed in 3.11 with the addition of support for path-like objects in multiprocessing.

gh-106403 [https://github.com/python/cpython/issues/106403]: Instances of typing.TypeVar, typing.ParamSpec, typing.ParamSpecArgs, typing.ParamSpecKwargs, and typing.TypeVarTuple once again support weak references, fixing a regression introduced in Python 3.12.0 beta 1. Patch by Jelle Zijlstra.

gh-89812 [https://github.com/python/cpython/issues/89812]: Add private pathlib._PathBase class, which provides experimental support for virtual filesystems, and may be made public in a future version of Python.

gh-106292 [https://github.com/python/cpython/issues/106292]: Check for an instance-dict cached value in the __get__() method of functools.cached_property(). This better matches the pre-3.12 behavior and improves compatibility for users subclassing functools.cached_property() and adding a __set__() method.

gh-106350 [https://github.com/python/cpython/issues/106350]: Detect possible memory allocation failure in the libtommath function mp_init() used by the _tkinter module.

gh-106330 [https://github.com/python/cpython/issues/106330]: Fix incorrect matching of empty paths in pathlib.PurePath.match(). This bug was introduced in Python 3.12.0 beta 1.

gh-106309 [https://github.com/python/cpython/issues/106309]: Deprecate typing.no_type_check_decorator(). No major type checker ever added support for this decorator. Patch by Alex Waygood.

gh-102541 [https://github.com/python/cpython/issues/102541]: Make pydoc.doc() catch bad module ImportError when output stream is not None.

gh-106263 [https://github.com/python/cpython/issues/106263]: Fix crash when calling repr with a manually constructed SignalDict object. Patch by Charlie Zhao.

gh-106236 [https://github.com/python/cpython/issues/106236]: Replace assert statements with raise RuntimeError in threading, so that _DummyThread cannot be joined even with -OO.

gh-106238 [https://github.com/python/cpython/issues/106238]: Fix rare concurrency bug in lock acquisition by the logging package.

gh-106152 [https://github.com/python/cpython/issues/106152]: Added PY_THROW event hook for cProfile for generators

gh-106075 [https://github.com/python/cpython/issues/106075]: Added asyncio.taskgroups.__all__ to asyncio.__all__ for export in star imports.

gh-104527 [https://github.com/python/cpython/issues/104527]: Zipapp will now skip over appending an archive to itself.

gh-106046 [https://github.com/python/cpython/issues/106046]: Improve the error message from os.fspath() if called on an object where __fspath__ is set to None. Patch by Alex Waygood.

gh-105987 [https://github.com/python/cpython/issues/105987]: Fix crash due to improper reference counting in asyncio eager task factory internal routines.

gh-105974 [https://github.com/python/cpython/issues/105974]: Fix bug where a typing.Protocol class that had one or more non-callable members would raise TypeError when issubclass() was called against it, even if it defined a custom __subclasshook__ method. The behaviour in Python 3.11 and lower – which has now been restored – was not to raise TypeError in these situations if a custom __subclasshook__ method was defined. Patch by Alex Waygood.

gh-96145 [https://github.com/python/cpython/issues/96145]: Reverted addition of json.AttrDict.

gh-89812 [https://github.com/python/cpython/issues/89812]: Add pathlib.UnsupportedOperation, which is raised instead of NotImplementedError when a path operation isn’t supported.

gh-105808 [https://github.com/python/cpython/issues/105808]: Fix a regression introduced in gh-101251 [https://github.com/python/cpython/issues/101251] for 3.12, causing gzip.GzipFile.flush() to not flush the compressor (nor pass along the zip_mode argument).

gh-105481 [https://github.com/python/cpython/issues/105481]: stack_effect() no longer raises an exception if an oparg is provided for an opcode that doesn’t use its arg, or when it is not provided for an opcode that does use it. In the latter case, the stack effect is returned for oparg=0.

gh-104799 [https://github.com/python/cpython/issues/104799]: Enable ast.unparse() to unparse function and class definitions created without the new type_params field from PEP 695 [https://peps.python.org/pep-0695/]. Patch by Jelle Zijlstra.

gh-105793 [https://github.com/python/cpython/issues/105793]: Add follow_symlinks keyword-only argument to pathlib.Path.is_dir() and is_file(), defaulting to True.

gh-105570 [https://github.com/python/cpython/issues/105570]: Deprecate two methods of creating typing.TypedDict classes with 0 fields using the functional syntax: TD = TypedDict("TD") and TD = TypedDict("TD", None). Both will be disallowed in Python 3.15. To create a TypedDict class with 0 fields, either use class TD(TypedDict): pass or TD = TypedDict("TD", {}).

gh-105745 [https://github.com/python/cpython/issues/105745]: Fix webbrowser.Konqueror.open method.

gh-105733 [https://github.com/python/cpython/issues/105733]: ctypes: Deprecate undocumented ctypes.SetPointerType() and ctypes.ARRAY() functions. Patch by Victor Stinner.

gh-105687 [https://github.com/python/cpython/issues/105687]: Remove deprecated re.template, re.T, re.TEMPLATE, sre_constans.SRE_FLAG_TEMPLATE.

gh-105684 [https://github.com/python/cpython/issues/105684]: Supporting asyncio.Task.set_name() is now mandatory for third party task implementations. The undocumented _set_task_name() function (deprecated since 3.8) has been removed. Patch by Kumar Aditya.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix a bug in _Unpickler_SetInputStream() where an exception could end up being overwritten in case of failure.

gh-105626 [https://github.com/python/cpython/issues/105626]: Change the default return value of http.client.HTTPConnection.get_proxy_response_headers() to be None and not {}.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in sys where exceptions could end up being overwritten because of deferred error handling.

gh-105605 [https://github.com/python/cpython/issues/105605]: Harden pyexpat error handling during module initialisation to prevent exceptions from possibly being overwritten, and objects from being dereferenced twice.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bug in decimal where an exception could end up being overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in _datetime where exceptions could be overwritten in case of module initialisation failure.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in _ssl initialisation which could lead to leaked references and overwritten exceptions.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix a bug in array.array where an exception could end up being overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in _ctypes where exceptions could end up being overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix a bug in the posix module where an exception could be overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in _elementtree where exceptions could be overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in zoneinfo where exceptions could be overwritten.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in errno where exceptions could be overwritten.

gh-105566 [https://github.com/python/cpython/issues/105566]: Deprecate creating a typing.NamedTuple class using keyword arguments to denote the fields (NT = NamedTuple("NT", x=int, y=str)). This will be disallowed in Python 3.15. Use the class-based syntax or the functional syntax instead.

Two methods of creating NamedTuple classes with 0 fields using the functional syntax are also deprecated, and will be disallowed in Python 3.15: NT = NamedTuple("NT") and NT = NamedTuple("NT", None). To create a NamedTuple class with 0 fields, either use class NT(NamedTuple): pass or NT = NamedTuple("NT", []).

gh-105545 [https://github.com/python/cpython/issues/105545]: Remove deprecated in 3.11 webbrowser.MacOSXOSAScript._name attribute.

gh-105497 [https://github.com/python/cpython/issues/105497]: Fix flag inversion when alias/mask members exist.

gh-105509 [https://github.com/python/cpython/issues/105509]: typing.Annotated is now implemented as an instance of typing._SpecialForm rather than a class. This should have no user-facing impact for users of the typing module public API.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix bugs in pickle where exceptions could be overwritten.

gh-70303 [https://github.com/python/cpython/issues/70303]: Emit FutureWarning from pathlib.Path.glob() and rglob() if the given pattern ends with “**”. In a future Python release, patterns with this ending will match both files and directories. Add a trailing slash to only match directories.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix a bug in sqlite3 where an exception could be overwritten in the collation callback.

gh-105382 [https://github.com/python/cpython/issues/105382]: Remove cafile, capath and cadefault parameters of the urllib.request.urlopen() function, deprecated in Python 3.6. Patch by Victor Stinner.

gh-105376 [https://github.com/python/cpython/issues/105376]: logging: Remove undocumented and untested Logger.warn() and LoggerAdapter.warn() methods and logging.warn() function. Deprecated since Python 3.3, they were aliases to the logging.Logger.warning() method, logging.LoggerAdapter.warning() method and logging.warning() function. Patch by Victor Stinner.

gh-105332 [https://github.com/python/cpython/issues/105332]: Revert pickling method from by-name back to by-value.

gh-104554 [https://github.com/python/cpython/issues/104554]: Add RTSPS scheme support in urllib.parse

gh-105292 [https://github.com/python/cpython/issues/105292]: Add option to traceback.format_exception_only() to recurse into the nested exception of a BaseExceptionGroup.

gh-105280 [https://github.com/python/cpython/issues/105280]: Fix bug where isinstance([], collections.abc.Mapping) could evaluate to True if garbage collection happened at the wrong time. The bug was caused by changes to the implementation of typing.Protocol in Python 3.12.

gh-80480 [https://github.com/python/cpython/issues/80480]: array: Add 'w' typecode that represents Py_UCS4.

gh-105239 [https://github.com/python/cpython/issues/105239]: Fix longstanding bug where issubclass(object, typing.Protocol) would evaluate to True in some edge cases. Patch by Alex Waygood.

gh-104310 [https://github.com/python/cpython/issues/104310]: In the beta 1 release we added a utility function for extension module authors, to use when testing their module for support in multiple interpreters or under a per-interpreter GIL. The name of that function has changed from allowing_all_extensions to _incompatible_extension_module_restrictions. The default for the “disable_check” argument has change from True to False, to better match the new function name.

gh-105080 [https://github.com/python/cpython/issues/105080]: Fixed inconsistent signature on derived classes for inspect.signature()

gh-105144 [https://github.com/python/cpython/issues/105144]: Fix a recent regression in the typing module. The regression meant that doing class Foo(X, typing.Protocol), where X was a class that had abc.ABCMeta as its metaclass, would then cause subsequent isinstance(1, X) calls to erroneously raise TypeError. Patch by Alex Waygood.

gh-62948 [https://github.com/python/cpython/issues/62948]: The io.IOBase finalizer now logs the close() method errors with sys.unraisablehook. Previously, errors were ignored silently by default, and only logged in Python Development Mode or on Python built on debug mode. Patch by Victor Stinner.

gh-105096 [https://github.com/python/cpython/issues/105096]: wave: Deprecate the getmark(), setmark() and getmarkers() methods of the wave.Wave_read and wave.Wave_write classes. They will be removed in Python 3.15. Patch by Victor Stinner.

gh-104992 [https://github.com/python/cpython/issues/104992]: Remove the untested and undocumented unittest.TestProgram.usageExit() method, deprecated in Python 3.11. Patch by Hugo van Kemenade.

gh-104996 [https://github.com/python/cpython/issues/104996]: Improve performance of pathlib.PurePath initialisation by deferring joining of paths when multiple arguments are given.

gh-101588 [https://github.com/python/cpython/issues/101588]: Deprecate undocumented copy/deepcopy/pickle support for itertools.

gh-103631 [https://github.com/python/cpython/issues/103631]: Fix pathlib.PurePosixPath(pathlib.PureWindowsPath(...)) not converting path separators to restore 3.11 compatible behavior.

gh-104947 [https://github.com/python/cpython/issues/104947]: Make comparisons between pathlib.PureWindowsPath objects consistent across Windows and Posix to match 3.11 behavior.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the audioop module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the aifc module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the uu module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104935 [https://github.com/python/cpython/issues/104935]: Fix bugs with the interaction between typing.runtime_checkable() and typing.Generic that were introduced by the PEP 695 [https://peps.python.org/pep-0695/] implementation. Patch by Jelle Zijlstra.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the crypt module and its private _crypt extension, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the nis module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104898 [https://github.com/python/cpython/issues/104898]: Add missing __slots__ to os.PathLike.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the xdrlib module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the nntplib module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104886 [https://github.com/python/cpython/issues/104886]: Remove the undocumented configparser.LegacyInterpolation class, deprecated in the docstring since Python 3.2, and with a deprecation warning since Python 3.11. Patch by Hugo van Kemenade.

gh-104786 [https://github.com/python/cpython/issues/104786]: Remove kwargs-based typing.TypedDict creation

gh-104876 [https://github.com/python/cpython/issues/104876]: Remove the turtle.RawTurtle.settiltangle() method, deprecated in docs since Python 3.1 and with a deprecation warning since Python 3.11. Patch by Hugo van Kemenade.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Removed the msilib package, deprecated in Python 3.11.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the spwd module, deprecated in Python 3.11: the python-pam [https://pypi.org/project/python-pam/] project can be used instead. Patch by Victor Stinner.

gh-75552 [https://github.com/python/cpython/issues/75552]: Removed the tkinter.tix module, deprecated since Python 3.6.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the chunk module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the mailcap module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the sunau module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104780 [https://github.com/python/cpython/issues/104780]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the ossaudiodev module, deprecated in Python 3.11. Patch Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the pipes module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104873 [https://github.com/python/cpython/issues/104873]: Add typing.get_protocol_members() to return the set of members defining a typing.Protocol. Add typing.is_protocol() to check whether a class is a typing.Protocol. Patch by Jelle Zijlstra.

gh-104874 [https://github.com/python/cpython/issues/104874]: Document the __name__ and __supertype__ attributes of typing.NewType. Patch by Jelle Zijlstra.

gh-104835 [https://github.com/python/cpython/issues/104835]: Removed the following unittest functions, deprecated in Python 3.11:

unittest.findTestCases()

unittest.makeSuite()

unittest.getTestCaseNames()

Use TestLoader methods instead:

unittest.TestLoader.loadTestsFromModule()

unittest.TestLoader.loadTestsFromTestCase()

unittest.TestLoader.getTestCaseNames()

Patch by Hugo van Kemenade.

gh-104804 [https://github.com/python/cpython/issues/104804]: Remove the untested and undocumented webbrowser MacOSX class, deprecated in Python 3.11. Patch by Hugo van Kemenade.

gh-83863 [https://github.com/python/cpython/issues/83863]: Support for using pathlib.Path objects as context managers has been removed. Before Python 3.9, exiting the context manager marked a path as “closed”, which caused some (but not all!) methods to raise when called. Since Python 3.9, using a path as a context manager does nothing.

gh-104799 [https://github.com/python/cpython/issues/104799]: Adjust the location of the (see PEP 695 [https://peps.python.org/pep-0695/]) type_params field on ast.ClassDef, ast.AsyncFunctionDef, and ast.FunctionDef to better preserve backward compatibility. Patch by Jelle Zijlstra

gh-104797 [https://github.com/python/cpython/issues/104797]: Allow typing.Protocol classes to inherit from collections.abc.Buffer. Patch by Jelle Zijlstra.

gh-104783 [https://github.com/python/cpython/issues/104783]: Remove locale.resetlocale() function deprecated in Python 3.11. Patch by Victor Stinner.

gh-104780 [https://github.com/python/cpython/issues/104780]: Remove the 2to3 program and the lib2to3 module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the telnetlib module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the imghdr module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the cgi and cgitb modules, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104773 [https://github.com/python/cpython/issues/104773]: PEP 594 [https://peps.python.org/pep-0594/]: Remove the sndhdr module, deprecated in Python 3.11. Patch by Victor Stinner.

gh-104372 [https://github.com/python/cpython/issues/104372]: On Linux where subprocess can use the vfork() syscall for faster spawning, prevent the parent process from blocking other threads by dropping the GIL while it waits for the vfork’ed child process exec() outcome. This prevents spawning a binary from a slow filesystem from blocking the rest of the application.

gh-99108 [https://github.com/python/cpython/issues/99108]: We now release the GIL around built-in hashlib computations of reasonable size for the SHA families and MD5 hash functions, matching what our OpenSSL backed hash computations already does.

gh-102613 [https://github.com/python/cpython/issues/102613]: Improve performance of pathlib.Path.glob() when expanding a pattern with a non-terminal “**” component by filtering walked paths through a regular expression, rather than calling os.scandir() more than once on each directory.

gh-104399 [https://github.com/python/cpython/issues/104399]: Prepare the _tkinter module for building with Tcl 9.0 and future libtommath by replacing usage of deprecated functions mp_to_unsigned_bin_n() and mp_unsigned_bin_size() when necessary.

gh-102676 [https://github.com/python/cpython/issues/102676]: Add fields start_offset, cache_offset, end_offset, baseopname, baseopcode, jump_target and oparg to dis.Instruction.

gh-103558 [https://github.com/python/cpython/issues/103558]: Fixed parent argument validation mechanism of argparse. Improved test coverage.

gh-103464 [https://github.com/python/cpython/issues/103464]: Provide helpful usage messages when parsing incorrect pdb commands.

gh-103384 [https://github.com/python/cpython/issues/103384]: Generalize the regex pattern BaseConfigurator.INDEX_PATTERN to allow spaces and non-alphanumeric characters in keys.

gh-103124 [https://github.com/python/cpython/issues/103124]: Added multiline statement support for pdb

gh-101162 [https://github.com/python/cpython/issues/101162]: Forbid using builtins.issubclass() with types.GenericAlias as the first argument.

gh-103200 [https://github.com/python/cpython/issues/103200]: Fix cache repopulation semantics of zipimport.invalidate_caches(). The cache is now repopulated upon retrieving files with an invalid cache, not when the cache is invalidated.

gh-100061 [https://github.com/python/cpython/issues/100061]: Fix a bug that causes wrong matches for regular expressions with possessive qualifier.

gh-77609 [https://github.com/python/cpython/issues/77609]: Add follow_symlinks argument to pathlib.Path.glob() and rglob(), defaulting to false.

gh-102541 [https://github.com/python/cpython/issues/102541]: Hide traceback in help() prompt, when import failed.

gh-102120 [https://github.com/python/cpython/issues/102120]: Added a stream mode to tarfile that allows for reading archives without caching info about the inner files.

gh-102029 [https://github.com/python/cpython/issues/102029]: Deprecate passing any arguments to threading.RLock().

gh-88233 [https://github.com/python/cpython/issues/88233]: Refactored zipfile._strip_extra to use higher level abstractions for extras instead of a heavy-state loop.

gh-102024 [https://github.com/python/cpython/issues/102024]: Reduce calls of _idle_semaphore.release() in concurrent.futures.thread._worker().

gh-73435 [https://github.com/python/cpython/issues/73435]: Add support for recursive wildcards in pathlib.PurePath.match().

gh-84867 [https://github.com/python/cpython/issues/84867]: unittest.TestLoader no longer loads test cases from exact unittest.TestCase and unittest.FunctionTestCase classes.

gh-99203 [https://github.com/python/cpython/issues/99203]: Restore following CPython <= 3.10.5 behavior of shutil.make_archive(): do not create an empty archive if root_dir is not a directory, and, in that case, raise FileNotFoundError or NotADirectoryError regardless of format choice. Beyond the brought-back behavior, the function may now also raise these exceptions in dry_run mode.

gh-80480 [https://github.com/python/cpython/issues/80480]: Emit DeprecationWarning for array’s 'u' type code, deprecated in docs since Python 3.3.

gh-94924 [https://github.com/python/cpython/issues/94924]: unittest.mock.create_autospec() now properly returns coroutine functions compatible with inspect.iscoroutinefunction()

gh-94777 [https://github.com/python/cpython/issues/94777]: Fix hanging multiprocessing ProcessPoolExecutor when a child process crashes while data is being written in the call queue.

gh-92871 [https://github.com/python/cpython/issues/92871]: Remove the typing.io and typing.re namespaces, deprecated since Python 3.8. All items are still available from the main typing module.

bpo-43633 [https://bugs.python.org/issue?@action=redirect&bpo=43633]: Improve the textual representation of IPv4-mapped IPv6 addresses (RFC 4291 [https://datatracker.ietf.org/doc/html/rfc4291.html] Sections 2.2, 2.5.5.2) in ipaddress. Patch by Oleksandr Pavliuk.

bpo-44850 [https://bugs.python.org/issue?@action=redirect&bpo=44850]: Improve performance of operator.methodcaller() using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall convention. Patch by Anthony Lee and Pieter Eendebak.

bpo-44185 [https://bugs.python.org/issue?@action=redirect&bpo=44185]: unittest.mock.mock_open() will call the close() method of the file handle mock when it is exiting from the context manager. Patch by Samet Yaslan.

bpo-40988 [https://bugs.python.org/issue?@action=redirect&bpo=40988]: Improve performance of functools.singledispatchmethod by caching the generated dispatch wrapper. Optimization suggested by frederico. Patch by @mental32, Alex Waygood and Pieter Eendebak.

bpo-41768 [https://bugs.python.org/issue?@action=redirect&bpo=41768]: unittest.mock speccing no longer calls class properties. Patch by Melanie Witt.

bpo-18319 [https://bugs.python.org/issue?@action=redirect&bpo=18319]: Ensure gettext(msg) retrieve translations even if a plural form exists. In other words: gettext(msg) == ngettext(msg, '', 1).

bpo-17013 [https://bugs.python.org/issue?@action=redirect&bpo=17013]: Add ThreadingMock to unittest.mock that can be used to create Mock objects that can wait until they are called. Patch by Karthikeyan Singaravelan and Mario Corchero.

Documentation

gh-109209 [https://github.com/python/cpython/issues/109209]: The minimum Sphinx version required for the documentation is now 4.2.

gh-108826 [https://github.com/python/cpython/issues/108826]: dis module command-line interface is now mentioned in documentation.

gh-107305 [https://github.com/python/cpython/issues/107305]: Add documentation for PyInterpreterConfig and Py_NewInterpreterFromConfig(). Also clarify some of the nearby docs relative to per-interpreter GIL.

gh-107008 [https://github.com/python/cpython/issues/107008]: Document the curses module variables LINES and COLS.

gh-106948 [https://github.com/python/cpython/issues/106948]: Add a number of standard external names to nitpick_ignore.

gh-106232 [https://github.com/python/cpython/issues/106232]: Make timeit doc command lines compatible with Windows by using double quotes for arguments. This works on linux and macOS also.

gh-105172 [https://github.com/python/cpython/issues/105172]: Fixed functools.lru_cache() docstring accounting for typed argument’s different handling of str and int. Patch by Bar Harel.

gh-105052 [https://github.com/python/cpython/issues/105052]: Update timeit doc to specify that time in seconds is just the default.

gh-89455 [https://github.com/python/cpython/issues/89455]: Add missing documentation for the max_group_depth and max_group_width parameters and the exceptions attribute of the traceback.TracebackException class.

gh-89412 [https://github.com/python/cpython/issues/89412]: Add missing documentation for the end_lineno and end_offset attributes of the traceback.TracebackException class.

gh-104943 [https://github.com/python/cpython/issues/104943]: Remove mentions of old Python versions in typing.NamedTuple.

gh-54738 [https://github.com/python/cpython/issues/54738]: Add documentation on how to localize the argparse module.

gh-102823 [https://github.com/python/cpython/issues/102823]: Document the return type of x // y when x and y have type float.

gh-102759 [https://github.com/python/cpython/issues/102759]: Align function signature for functools.reduce in documentation and docstring with the C implementation.

Tests

gh-110647 [https://github.com/python/cpython/issues/110647]: Fix test_stress_modifying_handlers() of test_signal. Patch by Victor Stinner.

gh-103053 [https://github.com/python/cpython/issues/103053]: Fix test_tools.test_freeze on FreeBSD: run “make distclean” instead of “make clean” in the copied source directory to remove also the “python” program. Patch by Victor Stinner.

gh-110167 [https://github.com/python/cpython/issues/110167]: Fix a deadlock in test_socket when server fails with a timeout but the client is still running in its thread. Don’t hold a lock to call cleanup functions in doCleanups(). One of the cleanup function waits until the client completes, whereas the client could deadlock if it called addCleanup() in such situation. Patch by Victor Stinner.

gh-110388 [https://github.com/python/cpython/issues/110388]: Add tests for tty.

gh-81002 [https://github.com/python/cpython/issues/81002]: Add tests for termios.

gh-110367 [https://github.com/python/cpython/issues/110367]: regrtest: When using worker processes (-jN) with –verbose3 option, regrtest can now display the worker output even if a worker process does crash. Previously, sys.stdout and sys.stderr were replaced and so the worker output was lost on a crash. Patch by Victor Stinner.

gh-110267 [https://github.com/python/cpython/issues/110267]: Add tests for pickling and copying PyStructSequence objects. Patched by Xuehai Pan.

gh-110171 [https://github.com/python/cpython/issues/110171]: libregrtest now always sets and shows random.seed, so tests are more reproducible. Use --randseed flag to pass the explicit random seed for tests.

gh-110152 [https://github.com/python/cpython/issues/110152]: Remove Tools/scripts/run_tests.py and make hostrunnertest. Just run ./python -m test --slow-ci, make buildbottest or make test instead. Python test runner (regrtest) now handles cross-compilation and HOSTRUNNER. It also adds options to Python such fast -u -E -W default -bb when --fast-ci or --slow-ci option is used. Patch by Victor Stinner.

gh-110031 [https://github.com/python/cpython/issues/110031]: Skip test_threading tests using thread+fork if Python is built with Address Sanitizer (ASAN). Patch by Victor Stinner.

gh-110088 [https://github.com/python/cpython/issues/110088]: Fix test_asyncio timeouts: don’t measure the maximum duration, a test should not measure a CI performance. Only measure the minimum duration when a task has a timeout or delay. Add CLOCK_RES to test_asyncio.utils. Patch by Victor Stinner.

gh-109974 [https://github.com/python/cpython/issues/109974]: Fix race conditions in test_threading lock tests. Wait until a condition is met rather than using time.sleep() with a hardcoded number of seconds. Patch by Victor Stinner.

gh-110033 [https://github.com/python/cpython/issues/110033]: Fix test_interprocess_signal() of test_signal. Make sure that the subprocess.Popen object is deleted before the test raising an exception in a signal handler. Otherwise, Popen.__del__() can get the exception which is logged as Exception ignored in: ... and the test fails. Patch by Victor Stinner.

gh-109594 [https://github.com/python/cpython/issues/109594]: Fix test_timeout() of test_concurrent_futures.test_wait. Remove the future which may or may not complete depending if it takes longer than the timeout or not. Keep the second future which does not complete before wait() timeout. Patch by Victor Stinner.

gh-109972 [https://github.com/python/cpython/issues/109972]: Split test_gdb.py file into a test_gdb package made of multiple tests, so tests can now be run in parallel. Patch by Victor Stinner.

gh-109566 [https://github.com/python/cpython/issues/109566]: regrtest: When --fast-ci or --slow-ci option is used, regrtest now replaces the current process with a new process to add -u -W default -bb -E options to Python. Patch by Victor Stinner.

gh-109748 [https://github.com/python/cpython/issues/109748]: Fix test_zippath_from_non_installed_posix() of test_venv: don’t copy __pycache__/ sub-directories, because they can be modified by other Python tests running in parallel. Patch by Victor Stinner.

gh-109739 [https://github.com/python/cpython/issues/109739]: regrtest: Fix reference leak check on Windows. Disable the load tracker on Windows in the reference leak check mode (-R option). Patch by Victor Stinner.

gh-109276 [https://github.com/python/cpython/issues/109276]: regrtest: When a test fails with “env changed” and the –rerun option is used, the test is now re-run in verbose mode in a fresh process. Patch by Victor Stinner.

gh-103053 [https://github.com/python/cpython/issues/103053]: Skip test_freeze_simple_script() of test_tools.test_freeze if Python is built with ./configure --enable-optimizations, which means with Profile Guided Optimization (PGO): it just makes the test too slow. The freeze tool is tested by many other CIs with other (faster) compiler flags. Patch by Victor Stinner.

gh-109580 [https://github.com/python/cpython/issues/109580]: Skip test_perf_profiler if Python is built with ASAN, MSAN or UBSAN sanitizer. Python does crash randomly in this test on such build. Patch by Victor Stinner.

gh-109566 [https://github.com/python/cpython/issues/109566]: regrtest: Add --fast-ci and --slow-ci options. --fast-ci uses a default timeout of 10 minutes and -u all,-cpu (skip slowest tests). --slow-ci uses a default timeout of 20 minutes and -u all (run all tests). Patch by Victor Stinner.

gh-109425 [https://github.com/python/cpython/issues/109425]: libregrtest now decodes stdout of test worker processes with the “backslashreplace” error handler to log corrupted stdout, instead of failing with an error and not logging the stdout. Patch by Victor Stinner.

gh-109396 [https://github.com/python/cpython/issues/109396]: Fix test_socket.test_hmac_sha1() in FIPS mode. Use a longer key: FIPS mode requires at least of at least 112 bits. The previous key was only 32 bits. Patch by Victor Stinner.

gh-104736 [https://github.com/python/cpython/issues/104736]: Fix test_gdb on Python built with LLVM clang 16 on Linux ppc64le (ex: Fedora 38). Search patterns in gdb “bt” command output to detect when gdb fails to retrieve the traceback. For example, skip a test if Backtrace stopped: frame did not save the PC is found. Patch by Victor Stinner.

gh-109276 [https://github.com/python/cpython/issues/109276]: libregrtest now calls random.seed() before running each test file when -r/--randomize command line option is used. Moreover, it’s also called in worker processes. It should help to make tests more deterministic. Previously, it was only called once in the main process before running all test files and it was not called in worker processes. Patch by Victor Stinner.

gh-109276 [https://github.com/python/cpython/issues/109276]: libregrtest now uses a separated file descriptor to write test result as JSON. Previously, if a test wrote debug messages late around the JSON, the main test process failed to parse JSON. Patch by Victor Stinner.

gh-108996 [https://github.com/python/cpython/issues/108996]: Fix and enable test_msvcrt.

gh-109237 [https://github.com/python/cpython/issues/109237]: Fix test_site.test_underpth_basic() when the working directory contains at least one non-ASCII character: encode the ._pth file to UTF-8 and enable the UTF-8 Mode to use UTF-8 for the child process stdout. Patch by Victor Stinner.

gh-109230 [https://github.com/python/cpython/issues/109230]: Fix test_pyexpat.test_exception(): it can now be run from a directory different than Python source code directory. Before, the test failed in this case. Skip the test if Modules/pyexpat.c source is not available. Skip also the test on Python implementations other than CPython. Patch by Victor Stinner.

gh-108996 [https://github.com/python/cpython/issues/108996]: Add tests for msvcrt.

gh-109015 [https://github.com/python/cpython/issues/109015]: Fix test_asyncio, test_imaplib and test_socket tests on FreeBSD if the TCP blackhole is enabled (sysctl net.inet.tcp.blackhole). Skip the few tests which failed with ETIMEDOUT which such non standard configuration. Currently, the FreeBSD GCP image enables TCP and UDP blackhole [https://reviews.freebsd.org/D41751] (sysctl net.inet.tcp.blackhole=2 and sysctl net.inet.udp.blackhole=1). Patch by Victor Stinner.

gh-91960 [https://github.com/python/cpython/issues/91960]: Skip test_gdb if gdb is unable to retrieve Python frame objects: if a frame is <optimized out>. When Python is built with “clang -Og”, gdb can fail to retrieve the frame parameter of _PyEval_EvalFrameDefault(). In this case, tests like py_bt() are likely to fail. Without getting access to Python frames, python-gdb.py is mostly clueless on retrieving the Python traceback. Moreover, test_gdb is no longer skipped on macOS if Python is built with Clang. Patch by Victor Stinner.

gh-108962 [https://github.com/python/cpython/issues/108962]: Skip test_tempfile.test_flags() if chflags() fails with “OSError: [Errno 45] Operation not supported” (ex: on FreeBSD 13). Patch by Victor Stinner.

gh-91960 [https://github.com/python/cpython/issues/91960]: FreeBSD 13.2 CI coverage for pull requests is now provided by Cirrus-CI (a hosted CI service that supports Linux, macOS, Windows, and FreeBSD).

gh-89392 [https://github.com/python/cpython/issues/89392]: Removed support of test_main() function in tests. They now always use normal unittest test runner.

gh-108851 [https://github.com/python/cpython/issues/108851]: Fix test_tomllib recursion tests for WASI buildbots: reduce the recursion limit and compute the maximum nested array/dict depending on the current available recursion limit. Patch by Victor Stinner.

gh-108851 [https://github.com/python/cpython/issues/108851]: Add get_recursion_available() and get_recursion_depth() functions to the test.support module. Patch by Victor Stinner.

gh-108834 [https://github.com/python/cpython/issues/108834]: Add --fail-rerun option option to regrtest: if a test failed when then passed when rerun in verbose mode, exit the process with exit code 2 (error), instead of exit code 0 (success). Patch by Victor Stinner.

gh-108834 [https://github.com/python/cpython/issues/108834]: Rename regrtest --verbose2 option (-w) to --rerun. Keep --verbose2 as a deprecated alias. Patch by Victor Stinner.

gh-108834 [https://github.com/python/cpython/issues/108834]: When regrtest reruns failed tests in verbose mode (./python -m test --rerun), tests are now rerun in fresh worker processes rather than being executed in the main process. If a test does crash or is killed by a timeout, the main process can detect and handle the killed worker process. Tests are rerun in parallel if the -jN option is used to run tests in parallel. Patch by Victor Stinner.

gh-108822 [https://github.com/python/cpython/issues/108822]: regrtest now computes statistics on all tests: successes, failures and skipped. test_netrc, test_pep646_syntax and test_xml_etree now return results in their test_main() function. Patch by Victor Stinner and Alex Waygood.

gh-108794 [https://github.com/python/cpython/issues/108794]: The doctest.DocTestRunner.run() method now counts the number of skipped tests. Add doctest.DocTestRunner.skips and doctest.TestResults.skipped attributes. Patch by Victor Stinner.

gh-108388 [https://github.com/python/cpython/issues/108388]: Convert test_concurrent_futures to a package of 7 sub-tests. Patch by Victor Stinner.

gh-108388 [https://github.com/python/cpython/issues/108388]: Split test_multiprocessing_fork, test_multiprocessing_forkserver and test_multiprocessing_spawn into test packages. Each package is made of 4 sub-tests: processes, threads, manager and misc. It allows running more tests in parallel and so reduce the total test duration. Patch by Victor Stinner.

gh-105776 [https://github.com/python/cpython/issues/105776]: Fix test_cppext when the C compiler command -std=c11 option: remove -std= options from the compiler command. Patch by Victor Stinner.

gh-107652 [https://github.com/python/cpython/issues/107652]: Set up CIFuzz to run fuzz targets in GitHub Actions. Patch by Illia Volochii.

gh-107237 [https://github.com/python/cpython/issues/107237]: test_logging: Fix test_udp_reconnection() by increasing the timeout from 100 ms to 5 minutes (LONG_TIMEOUT). Patch by Victor Stinner.

gh-107178 [https://github.com/python/cpython/issues/107178]: Add the C API test for functions in the Mapping Protocol, the Sequence Protocol and some functions in the Object Protocol.

gh-106714 [https://github.com/python/cpython/issues/106714]: test_capi: Fix test_no_FatalError_infinite_loop() to no longer write a coredump, by using test.support.SuppressCrashReport. Patch by Victor Stinner.

gh-104090 [https://github.com/python/cpython/issues/104090]: Avoid creating a reference to the test object in collectedDurations().

gh-106752 [https://github.com/python/cpython/issues/106752]: Moved tests for zipfile.Path into Lib/test/test_zipfile/_path. Made zipfile._path a package.

gh-106690 [https://github.com/python/cpython/issues/106690]: Add .coveragerc to cpython repository for use with coverage package.

gh-101634 [https://github.com/python/cpython/issues/101634]: When running the Python test suite with -jN option, if a worker stdout cannot be decoded from the locale encoding report a failed testn so the exitcode is non-zero. Patch by Victor Stinner.

gh-105084 [https://github.com/python/cpython/issues/105084]: When the Python build is configured --with-wheel-pkg-dir, tests requiring the setuptools and wheel wheels will search for the wheels in WHEEL_PKG_DIR.

gh-81005 [https://github.com/python/cpython/issues/81005]: String tests are modified to reflect that str and unicode are merged in Python 3. Patch by Daniel Fortunov.

gh-103186 [https://github.com/python/cpython/issues/103186]: Suppress and assert expected RuntimeWarnings in test_sys_settrace.py

gh-69714 [https://github.com/python/cpython/issues/69714]: Add additional tests to calendar to achieve full test coverage.

Build

gh-103053 [https://github.com/python/cpython/issues/103053]: “make check-clean-src” now also checks if the “python” program is found in the source directory: fail with an error if it does exist. Patch by Victor Stinner.

gh-109191 [https://github.com/python/cpython/issues/109191]: Fix compile error when building with recent versions of libedit.

gh-110276 [https://github.com/python/cpython/issues/110276]: No longer ignore PROFILE_TASK failure silently: command used by Profile Guided Optimization (PGO). Patch by Victor Stinner.

gh-109566 [https://github.com/python/cpython/issues/109566]: Remove make testall target: use make buildbottest instead. Patch by Victor Stinner.

gh-109740 [https://github.com/python/cpython/issues/109740]: The experimental --disable-gil configure flag now includes “t” (for “threaded”) in extension ABI tags.

gh-109054 [https://github.com/python/cpython/issues/109054]: Fix building the _testcapi extension on Linux AArch64 which requires linking to libatomic when <cpython/pyatomic.h> is used: the _Py_atomic_or_uint64() function requires libatomic __atomic_fetch_or_8() on this platform. The configure script now checks if linking to libatomic is needed and generates a new LIBATOMIC variable used to build the _testcapi extension. Patch by Victor Stinner.

gh-63760 [https://github.com/python/cpython/issues/63760]: Fix Solaris build: no longer redefine the gethostname() function. Solaris defines the function since 2005. Patch by Victor Stinner, original patch by Jakub Kulík.

gh-108740 [https://github.com/python/cpython/issues/108740]: Fix a race condition in make regen-all. The deepfreeze.c source and files generated by Argument Clinic are now generated or updated before generating “global objects”. Previously, some identifiers may miss depending on the order in which these files were generated. Patch by Victor Stinner.

gh-108634 [https://github.com/python/cpython/issues/108634]: Python built with configure --with-trace-refs (tracing references) is now ABI compatible with Python release build and debug build. Patch by Victor Stinner.

gh-85283 [https://github.com/python/cpython/issues/85283]: The _stat C extension is now built with the limited C API. Patch by Victor Stinner.

gh-108447 [https://github.com/python/cpython/issues/108447]: Fix x86_64 GNU/Hurd build

gh-107814 [https://github.com/python/cpython/issues/107814]: When calling find_python.bat with -q it did not properly silence the output of nuget. That is now fixed.

gh-105481 [https://github.com/python/cpython/issues/105481]: Remove the make target regen-opcode-targets, merge its work into regen-opcode which repeats most of the calculation. This simplifies the code for the build and reduces code duplication.

gh-106881 [https://github.com/python/cpython/issues/106881]: Check for linux/limits.h before including it in Modules/posixmodule.c.

gh-95855 [https://github.com/python/cpython/issues/95855]: Refactor platform triplet detection code and add detection for MIPS soft float and musl libc.

gh-106962 [https://github.com/python/cpython/issues/106962]: Detect MPI compilers in configure.

gh-106118 [https://github.com/python/cpython/issues/106118]: Fix compilation for platforms without O_CLOEXEC. The issue was introduced with Python 3.12b1 in gh-103295 [https://github.com/python/cpython/issues/103295]. Patch by Erlend Aasland.

gh-105875 [https://github.com/python/cpython/issues/105875]: SQLite 3.15.2 or newer is required to build the sqlite3 extension module. Patch by Erlend Aasland.

gh-90005 [https://github.com/python/cpython/issues/90005]: Fix a regression in configure where we could end up unintentionally linking with libbsd.

gh-102404 [https://github.com/python/cpython/issues/102404]: Document how to perform a WASI build on Linux. Also add Tools/wasm/build_wasi.sh as a reference implementation of the docs.

gh-89886 [https://github.com/python/cpython/issues/89886]: Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate !configure.

gh-104692 [https://github.com/python/cpython/issues/104692]: Include commoninstall as a prerequisite for bininstall

This ensures that commoninstall is completed before bininstall is started when parallel builds are used (make -j install), and so the python3 symlink is only installed after all standard library modules are installed.

gh-101538 [https://github.com/python/cpython/issues/101538]: Add experimental wasi-threads support. Patch by Takashi Yamamoto.

Windows

gh-110437 [https://github.com/python/cpython/issues/110437]: Allows overriding the source of VC redistributables so that releases can be guaranteed to never downgrade between updates.

gh-109286 [https://github.com/python/cpython/issues/109286]: Update Windows installer to use SQLite 3.43.1.

gh-82367 [https://github.com/python/cpython/issues/82367]: os.path.realpath() now resolves MS-DOS style file names even if the file is not accessible. Patch by Moonsik Park.

gh-109991 [https://github.com/python/cpython/issues/109991]: Update Windows build to use OpenSSL 3.0.11.

gh-106242 [https://github.com/python/cpython/issues/106242]: Fixes realpath() to behave consistently when passed a path containing an embedded null character on Windows. In strict mode, it now raises OSError instead of the unexpected ValueError, and in non-strict mode will make the path absolute.

gh-83180 [https://github.com/python/cpython/issues/83180]: Changes the 윈도우 용 파이썬 런처 to prefer an active virtual environment when the launched script has a shebang line using a Unix-like virtual command, even if the command requests a specific version of Python.

gh-106844 [https://github.com/python/cpython/issues/106844]: Fix integer overflow and truncating by the null character in _winapi.LCMapStringEx() which affects ntpath.normcase().

gh-105436 [https://github.com/python/cpython/issues/105436]: Ensure that an empty environment block is terminated by two null characters, as is required by Windows.

gh-105146 [https://github.com/python/cpython/issues/105146]: Updated the links at the end of the installer to point to Discourse rather than the mailing lists.

gh-103646 [https://github.com/python/cpython/issues/103646]: When installed from the Microsoft Store, pip no longer defaults to per-user installs. However, as the install directory is unwritable, it should automatically decide to do a per-user install anyway. This should resolve issues when pip is passed an option that conflicts with --user.

gh-88745 [https://github.com/python/cpython/issues/88745]: Improve performance of shutil.copy2() by using the operating system’s CopyFile2 function. This may result in subtle changes to metadata copied along with some files, bringing them in line with normal OS behavior.

gh-104820 [https://github.com/python/cpython/issues/104820]: Fixes stat() and related functions on file systems that do not support file ID requests. This includes FAT32 and exFAT.

gh-104803 [https://github.com/python/cpython/issues/104803]: Add os.path.isdevdrive() to detect whether a path is on a Windows Dev Drive. Returns False on platforms that do not support Dev Drive, and is absent on non-Windows platforms.

macOS

gh-109286 [https://github.com/python/cpython/issues/109286]: Update macOS installer to use SQLite 3.43.1.

gh-109991 [https://github.com/python/cpython/issues/109991]: Update macOS installer to use OpenSSL 3.0.11.

gh-99079 [https://github.com/python/cpython/issues/99079]: Update macOS installer to use OpenSSL 3.0.9.

IDLE

gh-104719 [https://github.com/python/cpython/issues/104719]: Remove IDLE’s modification of tokenize.tabsize and test other uses of tokenize data and methods.

Tools/Demos

gh-109991 [https://github.com/python/cpython/issues/109991]: Update GitHub CI workflows to use OpenSSL 3.0.11 and multissltests to use 1.1.1w, 3.0.11, and 3.1.3.

gh-108494 [https://github.com/python/cpython/issues/108494]: Argument Clinic [https://devguide.python.org/development-tools/clinic/] now has a partial support of the Limited API: see documentation in the Python Developer’s Guide [https://devguide.python.org/development-tools/clinic/#clinic-howto-limited-capi] Patch by Victor Stinner.

gh-107704 [https://github.com/python/cpython/issues/107704]: It is now possible to deprecate passing keyword arguments for keyword-or-positional parameters with Argument Clinic, using the new / [from X.Y] syntax. (To be read as “positional-only from Python version X.Y”.) See documentation in the Python Developer’s Guide [https://devguide.python.org/development-tools/clinic/#clinic-howto-deprecate-keyword] for more information.

gh-107880 [https://github.com/python/cpython/issues/107880]: Argument Clinic can now clone __init__() and __new__() methods.

gh-104683 [https://github.com/python/cpython/issues/104683]: Add --exclude option to Argument Clinic CLI.

gh-95065 [https://github.com/python/cpython/issues/95065]: Argument Clinic now supports overriding automatically generated signature by using directive @text_signature. See documentation in the Python Developer’s Guide [https://devguide.python.org/development-tools/clinic/#clinic-howto-override-signature]

gh-107609 [https://github.com/python/cpython/issues/107609]: Fix duplicate module check in Argument Clinic. Previously, a duplicate definition would incorrectly be silently accepted. Patch by Erlend E. Aasland.

gh-107467 [https://github.com/python/cpython/issues/107467]: The Argument Clinic command-line tool now prints to stderr instead of stdout on failure.

gh-106970 [https://github.com/python/cpython/issues/106970]: Fix bugs in the Argument Clinic destination <name> clear command; the destination buffers would never be cleared, and the destination directive parser would simply continue to the fault handler after processing the command. Patch by Erlend E. Aasland.

gh-106706 [https://github.com/python/cpython/issues/106706]: Change bytecode syntax for families to remove redundant name matching pseudo syntax.

gh-106359 [https://github.com/python/cpython/issues/106359]: Argument Clinic now explicitly forbids “kwarg splats” in function calls used as annotations.

gh-103186 [https://github.com/python/cpython/issues/103186]: freeze now fetches CONFIG_ARGS from the original CPython instance the Makefile uses to call utility scripts. Patch by Ijtaba Hussain.

gh-95065 [https://github.com/python/cpython/issues/95065]: It is now possible to deprecate passing parameters positionally with Argument Clinic, using the new * [from X.Y] syntax. (To be read as “keyword-only from Python version X.Y”.) See documentation in the Python Developer’s Guide [https://devguide.python.org/development-tools/clinic/#clinic-howto-deprecate-positional] for more information. Patch by Erlend E. Aasland with help from Alex Waygood, Nikita Sobolev, and Serhiy Storchaka.

C API

gh-85283 [https://github.com/python/cpython/issues/85283]: If the Py_LIMITED_API macro is defined, Py_BUILD_CORE, Py_BUILD_CORE_BUILTIN and Py_BUILD_CORE_MODULE macros are now undefined by <Python.h>. Patch by Victor Stinner.

gh-110289 [https://github.com/python/cpython/issues/110289]: Add PyUnicode_EqualToUTF8AndSize() and PyUnicode_EqualToUTF8() functions.

gh-110235 [https://github.com/python/cpython/issues/110235]: Raise TypeError for duplicate/unknown fields in PyStructSequence constructor. Patched by Xuehai Pan.

gh-110014 [https://github.com/python/cpython/issues/110014]: Remove undocumented PY_TIMEOUT_MAX constant from the limited C API. Patch by Victor Stinner.

gh-109521 [https://github.com/python/cpython/issues/109521]: PyImport_GetImporter() now sets RuntimeError if it fails to get sys.path_hooks or sys.path_importer_cache or they are not list and dict correspondingly. Previously it could return NULL without setting error in obscure cases, crash or raise SystemError if these attributes have wrong type.

gh-108724 [https://github.com/python/cpython/issues/108724]: Add PyMutex internal-only lightweight locking API.

gh-85283 [https://github.com/python/cpython/issues/85283]: Add PySys_AuditTuple() function: similar to PySys_Audit(), but pass event arguments as a Python tuple object. Patch by Victor Stinner.

gh-108867 [https://github.com/python/cpython/issues/108867]: Add PyThreadState_GetUnchecked() function: similar to PyThreadState_Get(), but don’t kill the process with a fatal error if it is NULL. The caller is responsible to check if the result is NULL. Previously, the function was private and known as _PyThreadState_UncheckedGet(). Patch by Victor Stinner.

gh-108765 [https://github.com/python/cpython/issues/108765]: Python.h no longer includes the <ctype.h> standard header file. If needed, it should now be included explicitly. For example, it provides isalpha() and tolower() functions which are locale dependent. Python provides locale independent functions, like Py_ISALPHA() and Py_TOLOWER(). Patch by Victor Stinner.

gh-108765 [https://github.com/python/cpython/issues/108765]: Python.h no longer includes the <unistd.h> standard header file. If needed, it should now be included explicitly. For example, it provides the functions: close(), getpagesize(), getpid() and sysconf(). Patch by Victor Stinner.

gh-108765 [https://github.com/python/cpython/issues/108765]: Python.h no longer includes the <ieeefp.h> standard header. It was included for the finite() function which is now provided by the <math.h> header. It should now be included explicitly if needed. Remove also the HAVE_IEEEFP_H macro. Patch by Victor Stinner.

gh-108765 [https://github.com/python/cpython/issues/108765]: Python.h no longer includes these standard header files: <time.h>, <sys/select.h> and <sys/time.h>. If needed, they should now be included explicitly. For example, <time.h> provides the clock() and gmtime() functions, <sys/select.h> provides the select() function, and <sys/time.h> provides the futimes(), gettimeofday() and setitimer() functions. Patch by Victor Stinner.

gh-108511 [https://github.com/python/cpython/issues/108511]: Add functions PyObject_HasAttrWithError(), PyObject_HasAttrStringWithError(), PyMapping_HasKeyWithError() and PyMapping_HasKeyStringWithError().

gh-107073 [https://github.com/python/cpython/issues/107073]: Add PyObject_VisitManagedDict() and PyObject_ClearManagedDict() functions which must be called by the traverse and clear functions of a type using Py_TPFLAGS_MANAGED_DICT flag. Patch by Victor Stinner.

gh-108634 [https://github.com/python/cpython/issues/108634]: Python built with configure --with-trace-refs (tracing references) now supports the Limited API. Patch by Victor Stinner.

gh-108014 [https://github.com/python/cpython/issues/108014]: Add PyLong_AsInt() function: similar to PyLong_AsLong(), but store the result in a C int instead of a C long. Previously, it was known as the private function _PyLong_AsInt() (with an underscore prefix). Patch by Victor Stinner.

gh-108314 [https://github.com/python/cpython/issues/108314]: Add PyDict_ContainsString() function: same as PyDict_Contains(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*. Patch by Victor Stinner.

gh-108337 [https://github.com/python/cpython/issues/108337]: Add atomic operations on additional data types in pyatomic.h.

gh-108014 [https://github.com/python/cpython/issues/108014]: Add Py_IsFinalizing() function: check if the main Python interpreter is shutting down. Patch by Victor Stinner.

gh-107916 [https://github.com/python/cpython/issues/107916]: C API functions PyErr_SetFromErrnoWithFilename(), PyErr_SetExcFromWindowsErrWithFilename() and PyErr_SetFromWindowsErrWithFilename() save now the error code before calling PyUnicode_DecodeFSDefault().

gh-107915 [https://github.com/python/cpython/issues/107915]: Such C API functions as PyErr_SetString(), PyErr_Format(), PyErr_SetFromErrnoWithFilename() and many others no longer crash or ignore errors if it failed to format the error message or decode the filename. Instead, they keep a corresponding error.

gh-107810 [https://github.com/python/cpython/issues/107810]: Improve DeprecationWarning for uses of PyType_Spec with metaclasses that have custom tp_new.

gh-107249 [https://github.com/python/cpython/issues/107249]: Implement the Py_UNUSED macro for Windows MSVC compiler. Patch by Victor Stinner.

gh-107226 [https://github.com/python/cpython/issues/107226]: PyModule_AddObjectRef() is now only available in the limited API version 3.10 or later.

gh-106320 [https://github.com/python/cpython/issues/106320]: Remove private _PyUnicode_AsString() alias to PyUnicode_AsUTF8(). It was kept for backward compatibility with Python 3.0 - 3.2. The PyUnicode_AsUTF8() is available since Python 3.3. The PyUnicode_AsUTF8String() function can be used to keep compatibility with Python 3.2 and older. Patch by Victor Stinner.

gh-106572 [https://github.com/python/cpython/issues/106572]: Convert PyObject_DelAttr() and PyObject_DelAttrString() macros to functions. Patch by Victor Stinner.

gh-106307 [https://github.com/python/cpython/issues/106307]: Add PyMapping_GetOptionalItem() function.

gh-106521 [https://github.com/python/cpython/issues/106521]: Add PyObject_GetOptionalAttr() and PyObject_GetOptionalAttrString() functions.

gh-106320 [https://github.com/python/cpython/issues/106320]: Remove _PyInterpreterState_Get() alias to PyInterpreterState_Get() which was kept for backward compatibility with Python 3.8. Patch by Victor Stinner.

gh-106316 [https://github.com/python/cpython/issues/106316]: Remove cpython/pytime.h header file: it only contained private functions. Patch by Victor Stinner.

gh-106023 [https://github.com/python/cpython/issues/106023]: Remove private _PyObject_FastCall() function: use PyObject_Vectorcall() which is available since Python 3.8 (PEP 590 [https://peps.python.org/pep-0590/]). Patch by Victor Stinner.

gh-106168 [https://github.com/python/cpython/issues/106168]: If Python is built in debug mode or with assertions, PyTuple_SET_ITEM() and PyList_SET_ITEM() now check the index argument with an assertion. If the assertion fails, make sure that the size is set before. Patch by Victor Stinner.

gh-106084 [https://github.com/python/cpython/issues/106084]: Remove the old aliases to functions calling functions which were kept for backward compatibility with Python 3.8 provisional API:

_PyObject_CallMethodNoArgs(): use PyObject_CallMethodNoArgs()

_PyObject_CallMethodOneArg(): use PyObject_CallMethodOneArg()

_PyObject_CallOneArg(): use PyObject_CallOneArg()

_PyObject_FastCallDict(): use PyObject_VectorcallDict()

_PyObject_Vectorcall(): use PyObject_Vectorcall()

_PyObject_VectorcallMethod(): use PyObject_VectorcallMethod()

_PyVectorcall_Function(): use PyVectorcall_Function()

Just remove the underscore prefix to update your code. Patch by Victor Stinner.

gh-106004 [https://github.com/python/cpython/issues/106004]: Adds PyDict_GetItemRef() and PyDict_GetItemStringRef() functions: similar to PyDict_GetItemWithError() but returning a strong reference instead of a borrowed reference. Patch by Victor Stinner.

gh-105927 [https://github.com/python/cpython/issues/105927]: Deprecate the PyWeakref_GetObject() and PyWeakref_GET_OBJECT() functions: use the new PyWeakref_GetRef() function instead. Patch by Victor Stinner.

gh-105927 [https://github.com/python/cpython/issues/105927]: Add PyWeakref_GetRef() function: similar to PyWeakref_GetObject() but returns a strong reference, or NULL if the referent is no longer live. Patch by Victor Stinner.

gh-105922 [https://github.com/python/cpython/issues/105922]: Add PyImport_AddModuleRef(): similar to PyImport_AddModule(), but return a strong reference instead of a borrowed reference. Patch by Victor Stinner.

gh-105227 [https://github.com/python/cpython/issues/105227]: The new PyType_GetDict() provides the dictionary for the given type object that is normally exposed by cls.__dict__. Normally it’s sufficient to use tp_dict, but for the static builtin types tp_dict is now always NULL. PyType_GetDict() provides the correct dict object instead.

gh-105375 [https://github.com/python/cpython/issues/105375]: Fix a bug in PyErr_WarnExplicit() where an exception could end up being overwritten if the API failed internally.

gh-105603 [https://github.com/python/cpython/issues/105603]: We’ve renamed the new (in 3.12) PyInterpreterConfig.own_gil to PyInterpreterConfig.gil and changed the meaning of the value from “bool” to an integer with supported values of PyInterpreterConfig_DEFAULT_GIL, PyInterpreterConfig_SHARED_GIL, and PyInterpreterConfig_OWN_GIL. The default is “shared”.

gh-105387 [https://github.com/python/cpython/issues/105387]: In the limited C API version 3.12, Py_INCREF() and Py_DECREF() functions are now implemented as opaque function calls to hide implementation details. Patch by Victor Stinner.

gh-105396 [https://github.com/python/cpython/issues/105396]: Deprecate the PyImport_ImportModuleNoBlock() function which is just an alias to PyImport_ImportModule() since Python 3.3. Patch by Victor Stinner.

gh-103968 [https://github.com/python/cpython/issues/103968]: PyType_FromMetaclass() now allows metaclasses with tp_new set to NULL.

gh-105268 [https://github.com/python/cpython/issues/105268]: Remove the old private, undocumented and untested _PyGC_FINALIZED() macro which was kept for backward compatibility with Python 3.8 and older. Patch by Victor Stinner.

gh-105182 [https://github.com/python/cpython/issues/105182]: Remove PyEval_AcquireLock() and PyEval_ReleaseLock() functions, deprecated in Python 3.2. Patch by Victor Stinner.

gh-105182 [https://github.com/python/cpython/issues/105182]: Remove PyEval_InitThreads() and PyEval_ThreadsInitialized() functions, deprecated in Python 3.9. Patch by Victor Stinner.

gh-105145 [https://github.com/python/cpython/issues/105145]: Deprecate old Python initialization functions:

PySys_ResetWarnOptions()

Py_GetExecPrefix()

Py_GetPath()

Py_GetPrefix()

Py_GetProgramFullPath()

Py_GetProgramName()

Py_GetPythonHome()

Patch by Victor Stinner.

gh-85275 [https://github.com/python/cpython/issues/85275]: PyObject_AsCharBuffer(), PyObject_AsReadBuffer(), PyObject_CheckReadBuffer(), and PyObject_AsWriteBuffer() are removed. Please migrate to new buffer protocol; PyObject_GetBuffer() and PyBuffer_Release().

gh-105156 [https://github.com/python/cpython/issues/105156]: Deprecate the old Py_UNICODE and PY_UNICODE_TYPE types: use directly the wchar_t type instead. Since Python 3.3, Py_UNICODE and PY_UNICODE_TYPE are just aliases to wchar_t. Patch by Victor Stinner.

gh-105145 [https://github.com/python/cpython/issues/105145]: Remove the following old functions to configure the Python initialization, deprecated in Python 3.11:

PySys_AddWarnOptionUnicode()

PySys_AddWarnOption()

PySys_AddXOption()

PySys_HasWarnOptions()

PySys_SetArgvEx()

PySys_SetArgv()

PySys_SetPath()

Py_SetPath()

Py_SetProgramName()

Py_SetPythonHome()

Py_SetStandardStreamEncoding()

_Py_SetProgramFullPath()

Patch by Victor Stinner.

gh-105107 [https://github.com/python/cpython/issues/105107]: Remove functions deprecated in Python 3.9.

PyEval_CallObject(), PyEval_CallObjectWithKeywords(): use PyObject_CallNoArgs() and PyObject_Call() (positional arguments must not be NULL) instead.

PyEval_CallFunction(): use PyObject_CallFunction() instead.

PyEval_CallMethod(): use PyObject_CallMethod() instead.

PyCFunction_Call(): use PyObject_Call() instead.

Patch by Victor Stinner.

gh-105115 [https://github.com/python/cpython/issues/105115]: PyTypeObject.tp_bases (and tp_mro) for builtin static types are now shared by all interpreters, whereas in 3.12-beta1 they were stored on PyInterpreterState. Also note that now the tuples are immortal objects.

gh-105071 [https://github.com/python/cpython/issues/105071]: Add PyUnstable_Exc_PrepReraiseStar to the unstable C api to expose the implementation of except*.

gh-104922 [https://github.com/python/cpython/issues/104922]: PY_SSIZE_T_CLEAN is no longer required to use '#' formats in APIs like PyArg_ParseTuple() and Py_BuildValue(). They uses Py_ssize_t for '#' regardless PY_SSIZE_T_CLEAN.

gh-104584 [https://github.com/python/cpython/issues/104584]: Add an unstable C API for hooking in an optimizer. This is mainly internal, but marked “unstable” to allow third-party experimentation.

gh-104668 [https://github.com/python/cpython/issues/104668]: Don’t call PyOS_InputHook or PyOS_ReadlineFunctionPointer in subinterpreters, since it’s generally difficult to avoid using global state in their registered callbacks. This also avoids situations where extensions may find themselves running in a subinterpreter they don’t support (or haven’t yet been loaded in).

bpo-42327 [https://bugs.python.org/issue?@action=redirect&bpo=42327]: Add PyModule_Add() function: similar to PyModule_AddObjectRef() and PyModule_AddObject(), but always steals a reference to the value.

bpo-40309 [https://bugs.python.org/issue?@action=redirect&bpo=40309]: Properly handle trailing spaces before closing parenthesis in Py_BuildValue() format strings.

Python 3.12.0 beta 1

Release date: 2023-05-22

Security

gh-99889 [https://github.com/python/cpython/issues/99889]: Fixed a security in flaw in uu.decode() that could allow for directory traversal based on the input if no out_file was specified.

gh-104049 [https://github.com/python/cpython/issues/104049]: Do not expose the local on-disk location in directory indexes produced by http.client.SimpleHTTPRequestHandler.

gh-99108 [https://github.com/python/cpython/issues/99108]: Upgrade built-in hashlib SHA3 implementation to a verified implementation from the HACL* project. Used when OpenSSL is not present or lacks SHA3.

gh-102153 [https://github.com/python/cpython/issues/102153]: urllib.parse.urlsplit() now strips leading C0 control and space characters following the specification for URLs defined by WHATWG in response to CVE 2023-24329 [https://www.cve.org/CVERecord?id=CVE-2023-24329]. Patch by Illia Volochii.

Core and Builtins

gh-102856 [https://github.com/python/cpython/issues/102856]: Implement PEP 701 changes in the tokenize module. Patch by Marta Gómez Macías and Pablo Galindo Salgado

gh-104615 [https://github.com/python/cpython/issues/104615]: Fix wrong ordering of assignments in code like a, a = x, y. Contributed by Carl Meyer.

gh-104572 [https://github.com/python/cpython/issues/104572]: Improve syntax error message for invalid constructs in PEP 695 [https://peps.python.org/pep-0695/] contexts and in annotations when from __future__ import annotations is active.

gh-104482 [https://github.com/python/cpython/issues/104482]: Fix three error handling bugs in ast.c’s validation of pattern matching statements.

gh-102818 [https://github.com/python/cpython/issues/102818]: Do not add a frame to the traceback in the sys.setprofile and sys.settrace trampoline functions. This ensures that frames are not duplicated if an exception is raised in the callback function, and ensures that frames are not omitted if a C callback is used and that does not add the frame.

gh-104405 [https://github.com/python/cpython/issues/104405]: Fix an issue where some bytecode instructions could ignore PEP 523 [https://peps.python.org/pep-0523/] when “inlining” calls.

gh-103082 [https://github.com/python/cpython/issues/103082]: Change behavior of sys.monitoring.events.LINE events in sys.monitoring: Line events now occur when a new line is reached dynamically, instead of using a static approximation, as before. This makes the behavior very similar to that of “line” events in sys.settrace. This should ease porting of tools from 3.11 to 3.12.

gh-104263 [https://github.com/python/cpython/issues/104263]: Fix float("nan") to produce a quiet NaN on platforms (like MIPS) where the meaning of the signalling / quiet bit is inverted from its usual meaning. Also introduce a new macro Py_INFINITY matching C99’s INFINITY, and refactor internals to rely on C99’s NAN and INFINITY macros instead of hard-coding bit patterns for infinities and NaNs. Thanks Sebastian Berg.

gh-99113 [https://github.com/python/cpython/issues/99113]: Multi-phase init extension modules may now indicate that they support running in subinterpreters that have their own GIL. This is done by using Py_MOD_PER_INTERPRETER_GIL_SUPPORTED as the value for the Py_mod_multiple_interpreters module def slot. Otherwise the module, by default, cannot be imported in such subinterpreters. (This does not affect the main interpreter or subinterpreters that do not have their own GIL.) In addition to the isolation that multi-phase init already normally requires, support for per-interpreter GIL involves one additional constraint: thread-safety. If the module has external (linked) dependencies and those libraries have any state that isn’t thread-safe then the module must do the additional work to add thread-safety. This should be an uncommon case.

gh-99113 [https://github.com/python/cpython/issues/99113]: The GIL is now (optionally) per-interpreter. This is the fundamental change for PEP 684. This is all made possible by virtue of the isolated state of each interpreter in the process. The behavior of the main interpreter remains unchanged. Likewise, interpreters created using Py_NewInterpreter() are not affected. To get an interpreter with its own GIL, call Py_NewInterpreterFromConfig().

gh-104108 [https://github.com/python/cpython/issues/104108]: Multi-phase init extension modules may now indicate whether or not they actually support multiple interpreters. By default such modules are expected to support use in multiple interpreters. In the uncommon case that one does not, it may use the new Py_mod_multiple_interpreters module def slot. A value of 0 means the module does not support them. 1 means it does. The default is 1.

gh-104142 [https://github.com/python/cpython/issues/104142]: Fix an issue where list or tuple repetition could fail to respect PEP 683 [https://peps.python.org/pep-0683/].

gh-104078 [https://github.com/python/cpython/issues/104078]: Improve the performance of PyObject_HasAttrString()

gh-104066 [https://github.com/python/cpython/issues/104066]: Improve the performance of hasattr() for module objects with a missing attribute.

gh-104028 [https://github.com/python/cpython/issues/104028]: Reduce object creation while calling callback function from gc. Patch by Donghee Na.

gh-104018 [https://github.com/python/cpython/issues/104018]: Disallow the “z” format specifier in %-format of bytes objects.

gh-102213 [https://github.com/python/cpython/issues/102213]: Fix performance loss when accessing an object’s attributes with __getattr__ defined.

gh-103895 [https://github.com/python/cpython/issues/103895]: Improve handling of edge cases in showing Exception.__notes__. Ensures that the messages always end with a newline and that string/bytes are not exploded over multiple lines. Patch by Carey Metcalfe.

gh-103907 [https://github.com/python/cpython/issues/103907]: Don’t modify the refcounts of known immortal objects (True, False, and None) in the main interpreter loop.

gh-103899 [https://github.com/python/cpython/issues/103899]: Provide a helpful hint in the TypeError message when accidentally calling a module object that has a callable attribute of the same name (such as dis.dis() or datetime.datetime).

gh-103845 [https://github.com/python/cpython/issues/103845]: Remove both line and instruction instrumentation before adding new ones for monitoring, to avoid newly added instrumentation being removed immediately.

gh-103763 [https://github.com/python/cpython/issues/103763]: Implement PEP 695 [https://peps.python.org/pep-0695/], adding syntactic support for generic classes, generic functions, and type aliases.

A new type X = ... syntax is added for type aliases, which resolves at runtime to an instance of the new class typing.TypeAliasType. The value is lazily evaluated and is accessible through the .__value__ attribute. This is implemented as a new AST node ast.TypeAlias.

New syntax (class X[T]: ..., def func[T](): ...) is added for defining generic functions and classes. This is implemented as a new type_params attribute on the AST nodes for classes and functions. This node holds instances of the new AST classes ast.TypeVar, ast.ParamSpec, and ast.TypeVarTuple.

typing.TypeVar, typing.ParamSpec, typing.ParamSpecArgs, typing.ParamSpecKwargs, typing.TypeVarTuple, and typing.Generic are now implemented in C rather than Python.

There are new bytecode instructions LOAD_LOCALS, LOAD_CLASSDICT_OR_GLOBAL, and LOAD_CLASSDICT_OR_DEREF to support correct resolution of names in class namespaces.

Patch by Eric Traut, Larry Hastings, and Jelle Zijlstra.

gh-103801 [https://github.com/python/cpython/issues/103801]: Adds three minor linting fixes to the wasm module caught that were caught by ruff.

gh-103793 [https://github.com/python/cpython/issues/103793]: Optimized asyncio Task creation by deferring expensive string formatting (task name generation) from Task creation to the first time get_name is called. This makes asyncio benchmarks up to 5% faster.

gh-102310 [https://github.com/python/cpython/issues/102310]: Change the error range for invalid bytes literals.

gh-103590 [https://github.com/python/cpython/issues/103590]: Do not wrap a single exception raised from a try-except* construct in an ExceptionGroup.

gh-103650 [https://github.com/python/cpython/issues/103650]: Change the perf map format to remove the ‘0x’ prefix from the addresses

gh-102856 [https://github.com/python/cpython/issues/102856]: Implement the required C tokenizer changes for PEP 701. Patch by Pablo Galindo Salgado, Lysandros Nikolaou, Batuhan Taskaya, Marta Gómez Macías and sunmy2019.

gh-100530 [https://github.com/python/cpython/issues/100530]: Clarify the error message raised when the called part of a class pattern isn’t actually a class.

gh-101517 [https://github.com/python/cpython/issues/101517]: Fix bug in line numbers of instructions emitted for except*.

gh-103492 [https://github.com/python/cpython/issues/103492]: Clarify SyntaxWarning with literal is comparison by specifying which literal is problematic, since comparisons using is with e.g. None and bool literals are idiomatic.

gh-87729 [https://github.com/python/cpython/issues/87729]: Add LOAD_SUPER_ATTR (and a specialization for super().method()) to speed up super().method() and super().attr. This makes super().method() roughly 2.3x faster and brings it within 20% of the performance of a simple method call. Patch by Vladimir Matveev and Carl Meyer.

gh-103488 [https://github.com/python/cpython/issues/103488]: Change the internal offset distinguishing yield and return target addresses, so that the instruction pointer is correct for exception handling and other stack unwinding.

gh-82012 [https://github.com/python/cpython/issues/82012]: The bitwise inversion operator (~) on bool is deprecated. It returns the bitwise inversion of the underlying int representation such that bool(~True) == True, which can be confusing. Use not for logical negation of bools. In the rare case that you really need the bitwise inversion of the underlying int, convert to int explicitly ~int(x).

gh-77757 [https://github.com/python/cpython/issues/77757]: Exceptions raised in a typeobject’s __set_name__ method are no longer wrapped by a RuntimeError. Context information is added to the exception as a PEP 678 [https://peps.python.org/pep-0678/] note.

gh-103333 [https://github.com/python/cpython/issues/103333]: AttributeError now retains the name attribute when pickled and unpickled.

gh-103242 [https://github.com/python/cpython/issues/103242]: Migrate set_ecdh_curve() method not to use deprecated OpenSSL APIs. Patch by Donghee Na.

gh-103323 [https://github.com/python/cpython/issues/103323]: We’ve replaced our use of _PyRuntime.tstate_current with a thread-local variable. This is a fairly low-level implementation detail, and there should be no change in behavior.

gh-84436 [https://github.com/python/cpython/issues/84436]: The implementation of PEP-683 which adds Immortal Objects by using a fixed reference count that skips reference counting to make objects truly immutable.

gh-102700 [https://github.com/python/cpython/issues/102700]: Allow built-in modules to be submodules. This allows submodules to be statically linked into a CPython binary.

gh-103082 [https://github.com/python/cpython/issues/103082]: Implement PEP 669 [https://peps.python.org/pep-0669/] Low Impact Monitoring for CPython.

gh-88691 [https://github.com/python/cpython/issues/88691]: Reduce the number of inline CACHE entries for CALL.

gh-102500 [https://github.com/python/cpython/issues/102500]: Make the buffer protocol accessible in Python code using the new __buffer__ and __release_buffer__ magic methods. See PEP 688 [https://peps.python.org/pep-0688/] for details. Patch by Jelle Zijlstra.

gh-97933 [https://github.com/python/cpython/issues/97933]: PEP 709 [https://peps.python.org/pep-0709/]: inline list, dict and set comprehensions to improve performance and reduce bytecode size.

gh-99184 [https://github.com/python/cpython/issues/99184]: Bypass instance attribute access of __name__ in repr of weakref.ref.

gh-98003 [https://github.com/python/cpython/issues/98003]: Complex function calls are now faster and consume no C stack space.

bpo-39610 [https://bugs.python.org/issue?@action=redirect&bpo=39610]: len() for 0-dimensional memoryview objects (such as memoryview(ctypes.c_uint8(42))) now raises a TypeError. Previously this returned 1, which was not consistent with mem_0d[0] raising an IndexError.

bpo-31821 [https://bugs.python.org/issue?@action=redirect&bpo=31821]: Fix pause_reading() to work when called from connection_made() in asyncio.

Library

gh-104600 [https://github.com/python/cpython/issues/104600]: functools.update_wrapper() now sets the __type_params__ attribute (added by PEP 695 [https://peps.python.org/pep-0695/]).

gh-104340 [https://github.com/python/cpython/issues/104340]: When an asyncio pipe protocol loses its connection due to an error, and the caller doesn’t await wait_closed() on the corresponding StreamWriter, don’t log a warning about an exception that was never retrieved. After all, according to the StreamWriter.close() docs, the wait_closed() call is optional (“not mandatory”).

gh-104555 [https://github.com/python/cpython/issues/104555]: Fix issue where an issubclass() check comparing a class X against a runtime-checkable protocol Y with non-callable members would not cause TypeError to be raised if an isinstance() call had previously been made comparing an instance of X to Y. This issue was present in edge cases on Python 3.11, but became more prominent in 3.12 due to some unrelated changes that were made to runtime-checkable protocols. Patch by Alex Waygood.

gh-104372 [https://github.com/python/cpython/issues/104372]: Refactored the _posixsubprocess internals to avoid Python C API usage between fork and exec when marking pass_fds= file descriptors inheritable.

gh-104484 [https://github.com/python/cpython/issues/104484]: Added case_sensitive argument to pathlib.PurePath.match()

gh-75367 [https://github.com/python/cpython/issues/75367]: Fix data descriptor detection in inspect.getattr_static().

gh-104536 [https://github.com/python/cpython/issues/104536]: Fix a race condition in the internal multiprocessing.process cleanup logic that could manifest as an unintended AttributeError when calling process.close().

gh-103857 [https://github.com/python/cpython/issues/103857]: Update datetime deprecations’ stracktrace to point to the calling line

gh-101520 [https://github.com/python/cpython/issues/101520]: Move the core functionality of the tracemalloc module in the Python/ folder, leaving just the module wrapper in Modules/.

gh-104392 [https://github.com/python/cpython/issues/104392]: Remove undocumented and unused _paramspec_tvars attribute from some classes in typing.

gh-102613 [https://github.com/python/cpython/issues/102613]: Fix issue where pathlib.Path.glob() raised RecursionError when walking deep directory trees.

gh-103000 [https://github.com/python/cpython/issues/103000]: Improve performance of dataclasses.asdict() for the common case where dict_factory is dict. Patch by David C Ellis.

gh-104301 [https://github.com/python/cpython/issues/104301]: Allow leading whitespace in disambiguated statements in pdb.

gh-104139 [https://github.com/python/cpython/issues/104139]: Teach urllib.parse.unsplit() to retain the "//" when assembling itms-services://?action=generate-bugs style Apple Platform Deployment [https://support.apple.com/en-gb/guide/deployment/depce7cefc4d/web] URLs.

gh-104307 [https://github.com/python/cpython/issues/104307]: socket.getnameinfo() now releases the GIL while contacting the DNS server

gh-104310 [https://github.com/python/cpython/issues/104310]: Users may now use importlib.util.allowing_all_extensions() (a context manager) to temporarily disable the strict compatibility checks for importing extension modules in subinterpreters.

gh-87695 [https://github.com/python/cpython/issues/87695]: Fix issue where pathlib.Path.glob() raised OSError when it encountered a symlink to an overly long path.

gh-104265 [https://github.com/python/cpython/issues/104265]: Prevent possible crash by disallowing instantiation of the _csv.Reader and _csv.Writer types. The regression was introduced in 3.10.0a4 with PR 23224 (bpo-14935 [https://bugs.python.org/issue?@action=redirect&bpo=14935]). Patch by Radislav Chugunov.

gh-102613 [https://github.com/python/cpython/issues/102613]: Improve performance of pathlib.Path.glob() when expanding recursive wildcards (”**”) by merging adjacent wildcards and de-duplicating results only when necessary.

gh-65772 [https://github.com/python/cpython/issues/65772]: Remove unneeded comments and code in turtle.py.

gh-90208 [https://github.com/python/cpython/issues/90208]: Fixed issue where pathlib.Path.glob() returned incomplete results when it encountered a PermissionError. This method now suppresses all OSError exceptions, except those raised from calling is_dir() on the top-level path.

gh-104144 [https://github.com/python/cpython/issues/104144]: Optimize asyncio.TaskGroup when using asyncio.eager_task_factory(). Skip scheduling a done callback if a TaskGroup task completes eagerly.

gh-104144 [https://github.com/python/cpython/issues/104144]: Optimize asyncio.gather() when using asyncio.eager_task_factory() to complete eagerly if all fututres completed eagerly. Avoid scheduling done callbacks for futures that complete eagerly.

gh-104114 [https://github.com/python/cpython/issues/104114]: Fix issue where pathlib.Path.glob() returns paths using the case of non-wildcard segments for corresponding path segments, rather than the real filesystem case.

gh-104104 [https://github.com/python/cpython/issues/104104]: Improve performance of pathlib.Path.glob() by using re.IGNORECASE to implement case-insensitive matching.

gh-104102 [https://github.com/python/cpython/issues/104102]: Improve performance of pathlib.Path.glob() when evaluating patterns that contain '../' segments.

gh-103822 [https://github.com/python/cpython/issues/103822]: Update the return type of weekday to the newly added Day attribute

gh-103629 [https://github.com/python/cpython/issues/103629]: Update the repr of typing.Unpack according to PEP 692 [https://peps.python.org/pep-0692/].

gh-103963 [https://github.com/python/cpython/issues/103963]: Make dis display the names of the args for CALL_INTRINSIC_*.

gh-104035 [https://github.com/python/cpython/issues/104035]: Do not ignore user-defined __getstate__ and __setstate__ methods for slotted frozen dataclasses.

gh-103987 [https://github.com/python/cpython/issues/103987]: In mmap, fix several bugs that could lead to access to memory-mapped files after they have been invalidated.

gh-103977 [https://github.com/python/cpython/issues/103977]: Improve import time of platform module.

gh-88773 [https://github.com/python/cpython/issues/88773]: Added turtle.teleport() to the turtle module to move a turtle to a new point without tracing a line, visible or invisible. Patch by Liam Gersten.

gh-103935 [https://github.com/python/cpython/issues/103935]: Use io.open_code() for files to be executed instead of raw open()

gh-68968 [https://github.com/python/cpython/issues/68968]: Fixed garbled output of assertEqual() when an input lacks final newline.

gh-100370 [https://github.com/python/cpython/issues/100370]: Fix potential OverflowError in sqlite3.Connection.blobopen() for 32-bit builds. Patch by Erlend E. Aasland.

gh-102628 [https://github.com/python/cpython/issues/102628]: Substitute CTRL-D with CTRL-Z in sqlite3 CLI banner when running on Windows.

gh-103636 [https://github.com/python/cpython/issues/103636]: Module-level attributes January and February are deprecated from calendar.

gh-103583 [https://github.com/python/cpython/issues/103583]: Isolate _multibytecodec and codecs extension modules. Patches by Erlend E. Aasland.

gh-103848 [https://github.com/python/cpython/issues/103848]: Add checks to ensure that [ bracketed ] hosts found by urllib.parse.urlsplit() are of IPv6 or IPvFuture format.

gh-103872 [https://github.com/python/cpython/issues/103872]: Update the bundled copy of pip to version 23.1.2.

gh-99944 [https://github.com/python/cpython/issues/99944]: Make dis display the value of oparg of KW_NAMES.

gh-74940 [https://github.com/python/cpython/issues/74940]: The C.UTF-8 locale is no longer converted to en_US.UTF-8, enabling the use of UTF-8 encoding on systems which have no locales installed.

gh-103861 [https://github.com/python/cpython/issues/103861]: Fix zipfile.Zipfile creating invalid zip files when force_zip64 was used to add files to them. Patch by Carey Metcalfe.

gh-103857 [https://github.com/python/cpython/issues/103857]: Deprecated datetime.datetime.utcnow() and datetime.datetime.utcfromtimestamp(). (Patch by Paul Ganssle)

gh-103839 [https://github.com/python/cpython/issues/103839]: Avoid compilation error due to tommath.h not being found when building Tkinter against Tcl 8.7 built with bundled libtommath.

gh-103791 [https://github.com/python/cpython/issues/103791]: contextlib.suppress now supports suppressing exceptions raised as part of an ExceptionGroup. If other exceptions exist on the group, they are re-raised in a group that does not contain the suppressed exceptions.

gh-90750 [https://github.com/python/cpython/issues/90750]: Use datetime.datetime.fromisocalendar() in the implementation of datetime.datetime.strptime(), which should now accept only valid ISO dates. (Patch by Paul Ganssle)

gh-103685 [https://github.com/python/cpython/issues/103685]: Prepare tkinter.Menu.index() for Tk 8.7 so that it does not raise TclError: expected integer but got "" when it should return None.

gh-81403 [https://github.com/python/cpython/issues/81403]: urllib.request.CacheFTPHandler no longer raises URLError if a cached FTP instance is reused. ftplib’s endtransfer method calls voidresp to drain the connection to handle FTP instance reuse properly.

gh-103699 [https://github.com/python/cpython/issues/103699]: Add __orig_bases__ to non-generic TypedDicts, call-based TypedDicts, and call-based NamedTuples. Other TypedDicts and NamedTuples already had the attribute.

gh-103693 [https://github.com/python/cpython/issues/103693]: Add convenience variable feature to pdb

gh-92248 [https://github.com/python/cpython/issues/92248]: Deprecate type, choices, and metavar parameters of argparse.BooleanOptionalAction.

gh-89415 [https://github.com/python/cpython/issues/89415]: Add socket constants for source-specific multicast. Patch by Reese Hyde.

gh-103673 [https://github.com/python/cpython/issues/103673]: socketserver gains ForkingUnixStreamServer and ForkingUnixDatagramServer classes. Patch by Jay Berry.

gh-103636 [https://github.com/python/cpython/issues/103636]: Added Enum for months and days in the calendar module.

gh-84976 [https://github.com/python/cpython/issues/84976]: Create a new Lib/_pydatetime.py file that defines the Python version of the datetime module, and make datetime import the contents of the new library only if the C implementation is missing. Currently, the full Python implementation is defined and then deleted if the C implementation is not available, slowing down import datetime unnecessarily.

gh-103596 [https://github.com/python/cpython/issues/103596]: Attributes/methods are no longer shadowed by same-named enum members, although they may be shadowed by enum.property’s.

gh-103584 [https://github.com/python/cpython/issues/103584]: Updated importlib.metadata with changes from importlib_metadata 5.2 through 6.5.0, including: Support installed-files.txt for Distribution.files when present. PackageMetadata now stipulates an additional get method allowing for easy querying of metadata keys that may not be present. packages_distributions now honors packages and modules with Python modules that not .py sources (e.g. .pyc, .so). Expand protocol for PackageMetadata.get_all to match the upstream implementation of email.message.Message.get_all in python/typeshed#9620. Deprecated use of Distribution without defining abstract methods. Deprecated expectation that PackageMetadata.__getitem__ will return None for missing keys. In the future, it will raise a KeyError.

gh-103578 [https://github.com/python/cpython/issues/103578]: Fixed a bug where pdb crashes when reading source file with different encoding by replacing io.open() with io.open_code(). The new method would also call into the hook set by PyFile_SetOpenCodeHook().

gh-103556 [https://github.com/python/cpython/issues/103556]: Now creating inspect.Signature objects with positional-only parameter with a default followed by a positional-or-keyword parameter without one is impossible.

gh-103559 [https://github.com/python/cpython/issues/103559]: Update the bundled copy of pip to version 23.1.1.

gh-103548 [https://github.com/python/cpython/issues/103548]: Improve performance of pathlib.Path.absolute() and cwd() by joining paths only when necessary. Also improve performance of pathlib.PurePath.is_absolute() on Posix by skipping path parsing and normalization.

gh-103538 [https://github.com/python/cpython/issues/103538]: Remove _tkinter module code guarded by definition of the TK_AQUA macro which was only needed for Tk 8.4.7 or earlier and was never actually defined by any build system or documented for manual use.

gh-103533 [https://github.com/python/cpython/issues/103533]: Update cProfile to use PEP 669 API

gh-103525 [https://github.com/python/cpython/issues/103525]: Fix misleading exception message when mixed str and bytes arguments are supplied to pathlib.PurePath and Path.

gh-103489 [https://github.com/python/cpython/issues/103489]: Add getconfig() and setconfig() to Connection to make configuration changes to a database connection. Patch by Erlend E. Aasland.

gh-103365 [https://github.com/python/cpython/issues/103365]: Set default Flag boundary to STRICT and fix bitwise operations.

gh-103472 [https://github.com/python/cpython/issues/103472]: Avoid a potential ResourceWarning in http.client.HTTPConnection by closing the proxy / tunnel’s CONNECT response explicitly.

gh-103462 [https://github.com/python/cpython/issues/103462]: Fixed an issue with using writelines() in asyncio to send very large payloads that exceed the amount of data that can be written in one call to socket.socket.send() or socket.socket.sendmsg(), resulting in the remaining buffer being left unwritten.

gh-103449 [https://github.com/python/cpython/issues/103449]: Fix a bug in doc string generation in dataclasses.dataclass().

gh-103092 [https://github.com/python/cpython/issues/103092]: Isolate _collections (apply PEP 687 [https://peps.python.org/pep-0687/]). Patch by Erlend E. Aasland.

gh-103357 [https://github.com/python/cpython/issues/103357]: Added support for logging.Formatter defaults parameter to logging.config.dictConfig() and logging.config.fileConfig(). Patch by Bar Harel.

gh-103092 [https://github.com/python/cpython/issues/103092]: Adapt the winreg extension module to PEP 687 [https://peps.python.org/pep-0687/].

gh-74690 [https://github.com/python/cpython/issues/74690]: The performance of isinstance() checks against runtime-checkable protocols has been considerably improved for protocols that only have a few members. To achieve this improvement, several internal implementation details of the typing module have been refactored, including typing._ProtocolMeta.__instancecheck__, typing._is_callable_members_only, and typing._get_protocol_attrs. Patches by Alex Waygood.

gh-74690 [https://github.com/python/cpython/issues/74690]: The members of a runtime-checkable protocol are now considered “frozen” at runtime as soon as the class has been created. See “What’s new in Python 3.12” for more details.

gh-103256 [https://github.com/python/cpython/issues/103256]: Fixed a bug that caused hmac to raise an exception when the requested hash algorithm was not available in OpenSSL despite being available separately as part of hashlib itself. It now falls back properly to the built-in. This could happen when, for example, your OpenSSL does not include SHA3 support and you want to compute hmac.digest(b'K', b'M', 'sha3_256').

gh-102778 [https://github.com/python/cpython/issues/102778]: Support sys.last_exc in idlelib.

gh-103285 [https://github.com/python/cpython/issues/103285]: Improve performance of ast.get_source_segment().

gh-103225 [https://github.com/python/cpython/issues/103225]: Fix a bug in pdb when displaying line numbers of module-level source code.

gh-103092 [https://github.com/python/cpython/issues/103092]: Adapt the msvcrt extension module to PEP 687 [https://peps.python.org/pep-0687/].

gh-103092 [https://github.com/python/cpython/issues/103092]: Adapt the winsound extension module to PEP 687 [https://peps.python.org/pep-0687/].

gh-93910 [https://github.com/python/cpython/issues/93910]: Remove deprecation of enum member.member access.

gh-102978 [https://github.com/python/cpython/issues/102978]: Fixes unittest.mock.patch() not enforcing function signatures for methods decorated with @classmethod or @staticmethod when patch is called with autospec=True.

gh-103092 [https://github.com/python/cpython/issues/103092]: Isolate _socket (apply PEP 687 [https://peps.python.org/pep-0687/]). Patch by Erlend E. Aasland.

gh-100479 [https://github.com/python/cpython/issues/100479]: Add pathlib.PurePath.with_segments(), which creates a path object from arguments. This method is called whenever a derivative path is created, such as from pathlib.PurePath.parent. Subclasses may override this method to share information between path objects.

gh-103220 [https://github.com/python/cpython/issues/103220]: Fix issue where os.path.join() added a slash when joining onto an incomplete UNC drive with a trailing slash on Windows.

gh-103204 [https://github.com/python/cpython/issues/103204]: Fixes http.server accepting HTTP requests with HTTP version numbers preceded by ‘+’, or ‘-’, or with digit-separating ‘_’ characters. The length of the version numbers is also constrained.

gh-75586 [https://github.com/python/cpython/issues/75586]: Fix various Windows-specific issues with shutil.which.

gh-103193 [https://github.com/python/cpython/issues/103193]: Improve performance of inspect.getattr_static(). Patch by Alex Waygood.

gh-103176 [https://github.com/python/cpython/issues/103176]: sys._current_exceptions() now returns a mapping from thread-id to an exception instance, rather than to a (typ, exc, tb) tuple.

gh-103143 [https://github.com/python/cpython/issues/103143]: Polish the help messages and docstrings of pdb.

gh-103015 [https://github.com/python/cpython/issues/103015]: Add entrypoint keyword-only parameter to sqlite3.Connection.load_extension(), for overriding the SQLite extension entry point. Patch by Erlend E. Aasland.

gh-103000 [https://github.com/python/cpython/issues/103000]: Improve performance of dataclasses.astuple() and dataclasses.asdict() in cases where the contents are common Python types.

gh-102953 [https://github.com/python/cpython/issues/102953]: The extraction methods in tarfile, and shutil.unpack_archive(), have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details.

gh-97696 [https://github.com/python/cpython/issues/97696]: Implemented an eager task factory in asyncio. When used as a task factory on an event loop, it performs eager execution of coroutines. Coroutines that are able to complete synchronously (e.g. return or raise without blocking) are returned immediately as a finished task, and the task is never scheduled to the event loop. If the coroutine blocks, the (pending) task is scheduled and returned.

gh-81079 [https://github.com/python/cpython/issues/81079]: Add case_sensitive keyword-only argument to pathlib.Path.glob() and rglob().

gh-101819 [https://github.com/python/cpython/issues/101819]: Isolate the io extension module by applying PEP 687 [https://peps.python.org/pep-0687/]. Patch by Kumar Aditya, Victor Stinner, and Erlend E. Aasland.

gh-91896 [https://github.com/python/cpython/issues/91896]: Deprecate collections.abc.ByteString

gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.Path construction by omitting the path anchor from the internal list of path parts.

gh-102114 [https://github.com/python/cpython/issues/102114]: Functions in the dis module that accept a source code string as argument now print a more concise traceback when the string contains a syntax or indentation error.

gh-62432 [https://github.com/python/cpython/issues/62432]: The unittest runner will now exit with status code 5 if no tests were run. It is common for test runner misconfiguration to fail to find any tests, this should be an error.

gh-78079 [https://github.com/python/cpython/issues/78079]: Fix incorrect normalization of UNC device path roots, and partial UNC share path roots, in pathlib.PurePath. Pathlib no longer appends a trailing slash to such paths.

gh-85984 [https://github.com/python/cpython/issues/85984]: Add tty.cfmakeraw() and tty.cfmakecbreak() to tty and modernize, the behavior of tty.setraw() and tty.setcbreak() to use POSIX.1-2017 Chapter 11 “General Terminal Interface” flag masks by default.

gh-101688 [https://github.com/python/cpython/issues/101688]: Implement types.get_original_bases() to provide further introspection for types.

gh-101640 [https://github.com/python/cpython/issues/101640]: argparse.ArgumentParser now catches errors when writing messages, such as when sys.stderr is None. Patch by Oleg Iarygin.

gh-83861 [https://github.com/python/cpython/issues/83861]: Fix datetime.astimezone method return value when invoked on a naive datetime instance that represents local time falling in a timezone transition gap. PEP 495 requires that instances with fold=1 produce earlier times than those with fold=0 in this case.

gh-89550 [https://github.com/python/cpython/issues/89550]: Decrease execution time of some gzip file writes by 15% by adding more appropriate buffering.

gh-95299 [https://github.com/python/cpython/issues/95299]: Remove the bundled setuptools wheel from ensurepip, and stop installing setuptools in environments created by venv.

gh-99353 [https://github.com/python/cpython/issues/99353]: Respect the http.client.HTTPConnection .debuglevel flag in urllib.request.AbstractHTTPHandler when its constructor parameter debuglevel is not set. And do the same for *HTTPS*.

gh-98040 [https://github.com/python/cpython/issues/98040]: Remove the long-deprecated imp module.

gh-97850 [https://github.com/python/cpython/issues/97850]: Deprecate pkgutil.find_loader() and pkgutil.get_loader() in favor of importlib.util.find_spec().

gh-94473 [https://github.com/python/cpython/issues/94473]: Flatten arguments in tkinter.Canvas.coords(). It now accepts not only x1, y1, x2, y2, ... and [x1, y1, x2, y2, ...], but also (x1, y1), (x2, y2), ... and [(x1, y1), (x2, y2), ...].

gh-98040 [https://github.com/python/cpython/issues/98040]: Remove more deprecated importlib APIs: find_loader(), find_module(), importlib.abc.Finder, pkgutil.ImpImporter, pkgutil.ImpLoader.

gh-96522 [https://github.com/python/cpython/issues/96522]: Fix potential deadlock in pty.spawn()

gh-96534 [https://github.com/python/cpython/issues/96534]: Support divert(4) added in FreeBSD 14.

gh-87474 [https://github.com/python/cpython/issues/87474]: Fix potential file descriptor leaks in subprocess.Popen.

gh-94906 [https://github.com/python/cpython/issues/94906]: Support multiple steps in math.nextafter(). Patch by Shantanu Jain and Matthias Gorgens.

gh-51574 [https://github.com/python/cpython/issues/51574]: Make tempfile.mkdtemp() return absolute paths when its dir parameter is relative.

gh-94518 [https://github.com/python/cpython/issues/94518]: Convert private _posixsubprocess.fork_exec() to use Argument Clinic.

gh-92184 [https://github.com/python/cpython/issues/92184]: When creating zip files using zipfile, os.altsep, if not None, will always be treated as a path separator even when it is not /. Patch by Carey Metcalfe.

bpo-46797 [https://bugs.python.org/issue?@action=redirect&bpo=46797]: Deprecation warnings are now emitted for ast.Num, ast.Bytes, ast.Str, ast.NameConstant and ast.Ellipsis. These have been documented as deprecated since Python 3.8, and will be removed in Python 3.14.

bpo-44844 [https://bugs.python.org/issue?@action=redirect&bpo=44844]: Enables webbrowser to detect and launch Microsoft Edge browser.

bpo-45606 [https://bugs.python.org/issue?@action=redirect&bpo=45606]: Fixed the bug in pathlib.Path.glob() – previously a dangling symlink would not be found by this method when the pattern is an exact match, but would be found when the pattern contains a wildcard or the recursive wildcard (**). With this change, a dangling symlink will be found in both cases.

bpo-23041 [https://bugs.python.org/issue?@action=redirect&bpo=23041]: Add QUOTE_STRINGS and QUOTE_NOTNULL to the suite of csv module quoting styles.

bpo-24964 [https://bugs.python.org/issue?@action=redirect&bpo=24964]: Added http.client.HTTPConnection.get_proxy_response_headers() that provides access to the HTTP headers on a proxy server response to the CONNECT request.

bpo-17258 [https://bugs.python.org/issue?@action=redirect&bpo=17258]: multiprocessing now supports stronger HMAC algorithms for inter-process connection authentication rather than only HMAC-MD5.

bpo-39744 [https://bugs.python.org/issue?@action=redirect&bpo=39744]: Make asyncio.subprocess.Process.communicate() close the subprocess’s stdin even when called with input=None.

bpo-22708 [https://bugs.python.org/issue?@action=redirect&bpo=22708]: http.client CONNECT method tunnel improvements: Use HTTP 1.1 protocol; send a matching Host: header with CONNECT, if one is not provided; convert IDN domain names to Punycode. Patch by Michael Handler.

Documentation

gh-67056 [https://github.com/python/cpython/issues/67056]: Document that the effect of registering or unregistering an atexit cleanup function from within a registered cleanup function is undefined.

gh-103629 [https://github.com/python/cpython/issues/103629]: Mention the new way of typing **kwargs with Unpack and TypedDict introduced in PEP 692 [https://peps.python.org/pep-0692/].

gh-48241 [https://github.com/python/cpython/issues/48241]: Clarifying documentation about the url parameter to urllib.request.urlopen and urllib.request.Request needing to be encoded properly.

gh-86094 [https://github.com/python/cpython/issues/86094]: Add support for Unicode Path Extra Field in ZipFile. Patch by Yeojin Kim and Andrea Giudiceandrea

gh-99202 [https://github.com/python/cpython/issues/99202]: Fix extension type from documentation for compiling in C++20 mode

Tests

gh-104494 [https://github.com/python/cpython/issues/104494]: Update test_pack_configure_in and test_place_configure_in for changes to error message formatting in Tk 8.7.

gh-104461 [https://github.com/python/cpython/issues/104461]: Run test_configure_screen on X11 only, since the DISPLAY environment variable and -screen option for toplevels are not useful on Tk for Win32 or Aqua.

gh-86275 [https://github.com/python/cpython/issues/86275]: Added property-based tests to the zoneinfo tests, along with stubs for the hypothesis interface. (Patch by Paul Ganssle)

gh-103329 [https://github.com/python/cpython/issues/103329]: Regression tests for the behaviour of unittest.mock.PropertyMock were added.

gh-102795 [https://github.com/python/cpython/issues/102795]: fix use of poll in test_epoll’s test_control_and_wait

gh-75729 [https://github.com/python/cpython/issues/75729]: Fix the os.spawn* tests failing on Windows when the working directory or interpreter path contains spaces.

Build

gh-101282 [https://github.com/python/cpython/issues/101282]: BOLT optimization is now applied to the libpython shared library if building a shared library. BOLT instrumentation and application settings can now be influenced via the BOLT_INSTRUMENT_FLAGS and BOLT_APPLY_FLAGS configure variables.

gh-99017 [https://github.com/python/cpython/issues/99017]: PYTHON_FOR_REGEN now require Python 3.10 or newer.

gh-104490 [https://github.com/python/cpython/issues/104490]: Define .PHONY / virtual make targets consistently and properly.

gh-104106 [https://github.com/python/cpython/issues/104106]: Add gcc fallback of mkfifoat/mknodat for macOS. Patch by Donghee Na.

gh-103532 [https://github.com/python/cpython/issues/103532]: The TKINTER_PROTECT_LOADTK macro is no longer defined or used in the _tkinter module. It was previously only defined when building against Tk 8.4.13 and older, but Tk older than 8.5.12 has been unsupported since gh-91152 [https://github.com/python/cpython/issues/91152].

gh-99069 [https://github.com/python/cpython/issues/99069]: Extended workaround defining static_assert when missing from the libc headers to all clang and gcc builds. In particular, this fixes building on macOS <= 10.10.

gh-100220 [https://github.com/python/cpython/issues/100220]: Changed the default value of the SHELL Makefile variable from /bin/sh to /bin/sh -e to ensure that complex recipes correctly fail after an error. Previously, make install could fail to install some files and yet return a successful result.

gh-90656 [https://github.com/python/cpython/issues/90656]: Add platform triplets for 64-bit LoongArch:

loongarch64-linux-gnusf

loongarch64-linux-gnuf32

loongarch64-linux-gnu

Patch by Zhang Na.

Windows

gh-104623 [https://github.com/python/cpython/issues/104623]: Update Windows installer to use SQLite 3.42.0.

gh-82814 [https://github.com/python/cpython/issues/82814]: Fix a potential [Errno 13] Permission denied when using shutil.copystat() within Windows Subsystem for Linux (WSL) on a mounted filesystem by adding errno.EACCES to the list of ignored errors within the internal implementation.

gh-103088 [https://github.com/python/cpython/issues/103088]: Fix virtual environment activate script having incorrect line endings for Cygwin.

gh-103088 [https://github.com/python/cpython/issues/103088]: Fixes venvs not working in bash on Windows across different disks

gh-102997 [https://github.com/python/cpython/issues/102997]: Update Windows installer to use SQLite 3.41.2.

gh-88013 [https://github.com/python/cpython/issues/88013]: Fixed a bug where TypeError was raised when calling ntpath.realpath() with a bytes parameter in some cases.

macOS

gh-99834 [https://github.com/python/cpython/issues/99834]: Update macOS installer to Tcl/Tk 8.6.13.

gh-104623 [https://github.com/python/cpython/issues/104623]: Update macOS installer to SQLite 3.42.0.

gh-103545 [https://github.com/python/cpython/issues/103545]: Add os.PRIO_DARWIN_THREAD, os.PRIO_DARWIN_PROCESS, os.PRIO_DARWIN_BG and os.PRIO_DARWIN_NONUI. These can be used with os.setpriority to run the process at a lower priority and make use of the efficiency cores on Apple Silicon systems.

gh-104180 [https://github.com/python/cpython/issues/104180]: Support reading SOCKS proxy configuration from macOS System Configuration. Patch by Sam Schott.

gh-60436 [https://github.com/python/cpython/issues/60436]: update curses textbox to additionally handle backspace using the curses.ascii.DEL key press.

gh-102997 [https://github.com/python/cpython/issues/102997]: Update macOS installer to SQLite 3.41.2.

IDLE

gh-104499 [https://github.com/python/cpython/issues/104499]: Fix completions for Tk Aqua 8.7 (currently blank).

gh-104496 [https://github.com/python/cpython/issues/104496]: About prints both tcl and tk versions if different (expected someday).

gh-88496 [https://github.com/python/cpython/issues/88496]: Fix IDLE test hang on macOS.

Tools/Demos

gh-104389 [https://github.com/python/cpython/issues/104389]: Argument Clinic C converters now accept the unused keyword, for wrapping a parameter with Py_UNUSED. Patch by Erlend E. Aasland.

C API

gh-101291 [https://github.com/python/cpython/issues/101291]: Added unstable C API for extracting the value of “compact” integers: PyUnstable_Long_IsCompact() and PyUnstable_Long_CompactValue().

gh-104109 [https://github.com/python/cpython/issues/104109]: We’ve added Py_NewInterpreterFromConfig() and PyInterpreterConfig to the public C-API (but not the stable ABI; not yet at least). The new function may be used to create a new interpreter with various features configured. The function was added to support PEP 684 (per-interpreter GIL).

gh-103968 [https://github.com/python/cpython/issues/103968]: PyType_FromSpec() and its variants now allow creating classes whose metaclass overrides tp_new. The tp_new is ignored. This behavior is deprecated and will be disallowed in 3.14+. The new PyType_FromMetaclass() already disallows it.

gh-103743 [https://github.com/python/cpython/issues/103743]: Add PyUnstable_Object_GC_NewWithExtraData() function that can be used to allocate additional memory after an object for data not managed by Python.

gh-103295 [https://github.com/python/cpython/issues/103295]: Introduced PyUnstable_WritePerfMapEntry(), PyUnstable_PerfMapState_Init() and PyUnstable_PerfMapState_Fini(). These allow extension modules (JIT compilers in particular) to write to perf-map files in a thread safe manner. The Python support for the Linux perf profiler also uses these APIs to write entries in the perf-map file.

gh-103509 [https://github.com/python/cpython/issues/103509]: Added C API for extending types whose instance memory layout is opaque: PyType_Spec.basicsize can now be zero or negative, PyObject_GetTypeData() can be used to get subclass-specific data, and Py_TPFLAGS_ITEMS_AT_END can be used to safely extend variable-size objects. See PEP 697 [https://peps.python.org/pep-0697/] for details.

gh-103091 [https://github.com/python/cpython/issues/103091]: Add a new C-API function to eagerly assign a version tag to a PyTypeObject: PyUnstable_Type_AssignVersionTag().

gh-101408 [https://github.com/python/cpython/issues/101408]: PyObject_GC_Resize should calculate preheader size if needed. Patch by Donghee Na.

gh-98836 [https://github.com/python/cpython/issues/98836]: Add support of more formatting options (left aligning, octals, uppercase hexadecimals, intmax_t, ptrdiff_t, wchar_t C strings, variable width and precision) in PyUnicode_FromFormat() and PyUnicode_FromFormatV().

gh-96803 [https://github.com/python/cpython/issues/96803]: Add unstable C-API functions to get the code object, lasti and line number from the internal _PyInterpreterFrame in the limited API. The functions are:

PyCodeObject * PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame)

int PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame)

int PyUnstable_InterpreterFrame_GetLine(struct _PyInterpreterFrame *frame)

Python 3.12.0 alpha 7

Release date: 2023-04-04

Core and Builtins

gh-102192 [https://github.com/python/cpython/issues/102192]: Deprecated _PyErr_ChainExceptions in favour of _PyErr_ChainExceptions1.

gh-89987 [https://github.com/python/cpython/issues/89987]: Reduce the number of inline CACHE entries for BINARY_SUBSCR.

gh-102859 [https://github.com/python/cpython/issues/102859]: Removed JUMP_IF_FALSE_OR_POP and JUMP_IF_TRUE_OR_POP instructions.

gh-101975 [https://github.com/python/cpython/issues/101975]: Fixed stacktop value on tracing entries to avoid corruption on garbage collection.

gh-102778 [https://github.com/python/cpython/issues/102778]: Add sys.last_exc and deprecate sys.last_type, sys.last_value and sys.last_traceback, which hold the same information in its legacy form.

gh-100982 [https://github.com/python/cpython/issues/100982]: Replace all occurrences of COMPARE_AND_BRANCH with COMPARE_OP.

gh-102701 [https://github.com/python/cpython/issues/102701]: Fix overflow when creating very large dict.

gh-102755 [https://github.com/python/cpython/issues/102755]: Add PyErr_DisplayException() which takes just an exception instance, to replace the legacy PyErr_Display() which takes the (typ, exc, tb) triplet.

gh-102594 [https://github.com/python/cpython/issues/102594]: Add note to exception raised in PyErr_SetObject when normalization fails.

gh-90997 [https://github.com/python/cpython/issues/90997]: Shrink the number of inline CACHE entries used by LOAD_GLOBAL.

gh-102491 [https://github.com/python/cpython/issues/102491]: Improve import time of platform by removing IronPython version parsing. The IronPython version parsing was not functional (see https://github.com/IronLanguages/ironpython3/issues/1667).

gh-101291 [https://github.com/python/cpython/issues/101291]: Rearrage bits in first field (after header) of PyLongObject. * Bits 0 and 1: 1 - sign. I.e. 0 for positive numbers, 1 for zero and 2 for negative numbers. * Bit 2 reserved (probably for the immortal bit) * Bits 3+ the unsigned size.

This makes a few operations slightly more efficient, and will enable a more compact and faster 2s-complement representation of most ints in future.

gh-102397 [https://github.com/python/cpython/issues/102397]: Fix segfault from race condition in signal handling during garbage collection. Patch by Kumar Aditya.

gh-102406 [https://github.com/python/cpython/issues/102406]: codecs encoding/decoding errors now get the context information (which operation and which codecs) attached as PEP 678 [https://peps.python.org/pep-0678/] notes instead of through chaining a new instance of the exception.

gh-102281 [https://github.com/python/cpython/issues/102281]: Fix potential nullptr dereference and use of uninitialized memory in fileutils. Patch by Max Bachmann.

gh-102300 [https://github.com/python/cpython/issues/102300]: Reuse operands with refcount of 1 in float specializations of BINARY_OP.

gh-102213 [https://github.com/python/cpython/issues/102213]: Fix performance loss when accessing an object’s attributes with __getattr__ defined.

gh-102255 [https://github.com/python/cpython/issues/102255]: Improve build support for the Xbox. Patch by Max Bachmann.

gh-102027 [https://github.com/python/cpython/issues/102027]: Fix SSE2 and SSE3 detection in _blake2 internal module. Patch by Max Bachmann.

gh-101865 [https://github.com/python/cpython/issues/101865]: Deprecate co_lnotab in code objects, schedule it for removal in Python 3.14

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Adapt _pickle to PEP 687 [https://peps.python.org/pep-0687/]. Patch by Mohamed Koubaa and Erlend Aasland.

Library

gh-103085 [https://github.com/python/cpython/issues/103085]: Pure python locale.getencoding() will not warn deprecation.

gh-103068 [https://github.com/python/cpython/issues/103068]: It’s no longer possible to register conditional breakpoints in Pdb that raise SyntaxError. Patch by Tian Gao.

gh-102549 [https://github.com/python/cpython/issues/102549]: Don’t ignore exceptions in member type creation.

gh-103056 [https://github.com/python/cpython/issues/103056]: Ensure final _generate_next_value_ is a staticmethod.

gh-103046 [https://github.com/python/cpython/issues/103046]: Display current line label correctly in dis when show_caches is False and lasti points to a CACHE entry.

gh-102433 [https://github.com/python/cpython/issues/102433]: isinstance() checks against runtime-checkable protocols now use inspect.getattr_static() rather than hasattr() to lookup whether attributes exist. This means that descriptors and __getattr__() methods are no longer unexpectedly evaluated during isinstance() checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change. Patch by Alex Waygood.

gh-103023 [https://github.com/python/cpython/issues/103023]: It’s no longer possible to register expressions to display in Pdb that raise SyntaxError. Patch by Tian Gao.

gh-102947 [https://github.com/python/cpython/issues/102947]: Improve traceback when dataclasses.fields() is called on a non-dataclass. Patch by Alex Waygood

gh-102780 [https://github.com/python/cpython/issues/102780]: The asyncio.Timeout context manager now works reliably even when performing cleanup due to task cancellation. Previously it could raise a CancelledError instead of an TimeoutError in such cases.

gh-102871 [https://github.com/python/cpython/issues/102871]: Remove support for obsolete browsers from webbrowser. Removed browsers include Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below.

gh-102839 [https://github.com/python/cpython/issues/102839]: Improve performance of math.log() arguments handling by removing the argument clinic.

gh-102828 [https://github.com/python/cpython/issues/102828]: Add the onexc arg to shutil.rmtree(), which is like onerror but expects an exception instance rather than an exc_info tuple. Deprecate onerror.

gh-88965 [https://github.com/python/cpython/issues/88965]: typing: Fix a bug relating to substitution in custom classes generic over a ParamSpec. Previously, if the ParamSpec was substituted with a parameters list that itself contained a TypeVar, the TypeVar in the parameters list could not be subsequently substituted. This is now fixed.

Patch by Nikita Sobolev.

gh-76846 [https://github.com/python/cpython/issues/76846]: Fix issue where __new__() and __init__() methods of pathlib.PurePath and Path subclasses were not called in some circumstances.

gh-78530 [https://github.com/python/cpython/issues/78530]: asyncio.wait() now accepts generators yielding tasks. Patch by Kumar Aditya.

gh-102748 [https://github.com/python/cpython/issues/102748]: asyncio.iscoroutine() now returns False for generators as asyncio does not support legacy generator-based coroutines. Patch by Kumar Aditya.

gh-102670 [https://github.com/python/cpython/issues/102670]: Optimized fmean(), correlation(), covariance(), and linear_regression() using the new math.sumprod() function.

gh-102615 [https://github.com/python/cpython/issues/102615]: Typing: Improve the repr of generic aliases for classes generic over a ParamSpec. (Use square brackets to represent a parameter list.)

gh-100112 [https://github.com/python/cpython/issues/100112]: asyncio.Task.get_coro() now always returns a coroutine when wrapping an awaitable object. Patch by Kumar Aditya.

gh-102578 [https://github.com/python/cpython/issues/102578]: Speed up setting or deleting mutable attributes on non-dataclass subclasses of frozen dataclasses. Due to the implementation of __setattr__ and __delattr__ for frozen dataclasses, this previously had a time complexity of O(n). It now has a time complexity of O(1).

gh-102519 [https://github.com/python/cpython/issues/102519]: Add os.listdrives(), os.listvolumes() and os.listmounts() functions on Windows for enumerating drives, volumes and mount points

gh-74468 [https://github.com/python/cpython/issues/74468]: Attribute name of the extracted tarfile file object now holds filename of itself rather than of the archive it is contained in. Patch by Oleg Iarygin.

gh-102378 [https://github.com/python/cpython/issues/102378]: Private helper method inspect._signature_strip_non_python_syntax will no longer strip / from the input string.

gh-79940 [https://github.com/python/cpython/issues/79940]: Add inspect.getasyncgenstate() and inspect.getasyncgenlocals(). Patch by Thomas Krennwallner.

gh-102103 [https://github.com/python/cpython/issues/102103]: Add module argument to dataclasses.make_dataclass() and make classes produced by it pickleable.

gh-102069 [https://github.com/python/cpython/issues/102069]: Fix __weakref__ descriptor generation for custom dataclasses.

gh-102038 [https://github.com/python/cpython/issues/102038]: Skip a stat in site if we have already found a pyvenv.cfg

gh-98886 [https://github.com/python/cpython/issues/98886]: Fix issues when defining dataclasses that have fields with specific underscore names that aren’t clearly reserved by dataclasses.

gh-101673 [https://github.com/python/cpython/issues/101673]: Fix a pdb bug where ll clears the changes to local variables.

gh-101313 [https://github.com/python/cpython/issues/101313]: Added -h and –help arguments to the webbrowser CLI

gh-100372 [https://github.com/python/cpython/issues/100372]: ssl.SSLContext.load_verify_locations() no longer incorrectly accepts some cases of trailing data when parsing DER.

gh-89727 [https://github.com/python/cpython/issues/89727]: Fix pathlib.Path.walk RecursionError on deep directory trees by rewriting it using iteration instead of recursion.

gh-100131 [https://github.com/python/cpython/issues/100131]: Added an optional delete keyword argument to tempfile.TemporaryDirectory.

gh-48330 [https://github.com/python/cpython/issues/48330]: Added --durations command line option, showing the N slowest test cases. unittest.TextTestRunner and unittest.TextTestResult constructors accept a new durations keyword argument. Subclasses should take this into account or accept **kwargs. Added unittest.TestResult.addDuration() method and unittest.TestResult.collectedDurations attribute.

(Contributed by Giampaolo Rodola)

gh-98169 [https://github.com/python/cpython/issues/98169]: Fix dataclasses.astuple() crash when collections.defaultdict is present in the attributes.

gh-96931 [https://github.com/python/cpython/issues/96931]: Fix incorrect results from ssl.SSLSocket.shared_ciphers()

gh-95495 [https://github.com/python/cpython/issues/95495]: When built against OpenSSL 3.0, the ssl module had a bug where it reported unauthenticated EOFs (i.e. without close_notify) as a clean TLS-level EOF. It now raises SSLEOFError, matching the behavior in previous versions of OpenSSL. The options attribute on SSLContext also no longer includes OP_IGNORE_UNEXPECTED_EOF by default. This option may be set to specify the previous OpenSSL 3.0 behavior.

gh-94684 [https://github.com/python/cpython/issues/94684]: Now uuid.uuid3() and uuid.uuid5() functions support bytes objects as their name argument.

gh-94440 [https://github.com/python/cpython/issues/94440]: Fix a concurrent.futures.process bug where ProcessPoolExecutor shutdown could hang after a future has been quickly submitted and canceled.

gh-72346 [https://github.com/python/cpython/issues/72346]: Added deprecation warning to isdst parameter of email.utils.localtime().

bpo-36305 [https://bugs.python.org/issue?@action=redirect&bpo=36305]: Fix handling of Windows filenames that resemble drives, such as ./a:b, in pathlib.

Documentation

gh-103112 [https://github.com/python/cpython/issues/103112]: Add docstring to http.client.HTTPResponse.read() to fix pydoc output.

Tests

gh-102980 [https://github.com/python/cpython/issues/102980]: Improve test coverage on pdb.

gh-102537 [https://github.com/python/cpython/issues/102537]: Adjust the error handling strategy in test_zoneinfo.TzPathTest.python_tzpath_context. Patch by Paul Ganssle.

gh-101377 [https://github.com/python/cpython/issues/101377]: Improved test_locale_calendar_formatweekday of calendar.

Build

gh-102973 [https://github.com/python/cpython/issues/102973]: Add a dev container (along with accompanying Dockerfile) for development purposes.

gh-102711 [https://github.com/python/cpython/issues/102711]: Fix -Wstrict-prototypes compiler warnings.

Windows

gh-102690 [https://github.com/python/cpython/issues/102690]: Update webbrowser to fall back to Microsoft Edge instead of Internet Explorer.

gh-99726 [https://github.com/python/cpython/issues/99726]: Improves correctness of stat results for Windows, and uses faster API when available

Tools/Demos

gh-102809 [https://github.com/python/cpython/issues/102809]: Misc/gdbinit was removed.

C API

gh-102013 [https://github.com/python/cpython/issues/102013]: Add a new (unstable) C-API function for iterating over GC’able objects using a callback: PyUnstable_VisitObjects.

Python 3.12.0 alpha 6

Release date: 2023-03-07

Security

gh-99108 [https://github.com/python/cpython/issues/99108]: Replace builtin hashlib implementations of MD5 and SHA1 with verified ones from the HACL* project.

gh-101727 [https://github.com/python/cpython/issues/101727]: Updated the OpenSSL version used in Windows and macOS binary release builds to 1.1.1t to address CVE 2023-0286 [https://www.cve.org/CVERecord?id=CVE-2023-0286], CVE 2022-4303 [https://www.cve.org/CVERecord?id=CVE-2022-4303], and CVE 2022-4303 [https://www.cve.org/CVERecord?id=CVE-2022-4303] per the OpenSSL 2023-02-07 security advisory [https://openssl-library.org/news/secadv/20230207.txt].

gh-99108 [https://github.com/python/cpython/issues/99108]: Replace the builtin hashlib implementations of SHA2-384 and SHA2-512 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* [https://github.com/hacl-star/hacl-star/] project. The builtins remain a fallback only used when OpenSSL does not provide them.

gh-101283 [https://github.com/python/cpython/issues/101283]: subprocess.Popen now uses a safer approach to find cmd.exe when launching with shell=True. Patch by Eryk Sun, based on a patch by Oleg Iarygin.

Core and Builtins

gh-102493 [https://github.com/python/cpython/issues/102493]: Fix regression in semantics of normalisation in PyErr_SetObject.

gh-102416 [https://github.com/python/cpython/issues/102416]: Do not memoize incorrectly automatically generated loop rules in the parser. Patch by Pablo Galindo.

gh-102356 [https://github.com/python/cpython/issues/102356]: Fix a bug that caused a crash when deallocating deeply nested filter objects. Patch by Marta Gómez Macías.

gh-102336 [https://github.com/python/cpython/issues/102336]: Cleanup Windows 7 specific special handling. Patch by Max Bachmann.

gh-102250 [https://github.com/python/cpython/issues/102250]: Fixed a segfault occurring when the interpreter calls a __bool__ method that raises.

gh-102126 [https://github.com/python/cpython/issues/102126]: Fix deadlock at shutdown when clearing thread states if any finalizer tries to acquire the runtime head lock. Patch by Kumar Aditya.

gh-102027 [https://github.com/python/cpython/issues/102027]: Use GetCurrentProcessId on Windows when getpid is unavailable. Patch by Max Bachmann.

gh-102056 [https://github.com/python/cpython/issues/102056]: Fix error handling bugs in interpreter’s exception printing code, which could cause a crash on infinite recursion.

gh-100982 [https://github.com/python/cpython/issues/100982]: Restrict the scope of the FOR_ITER_RANGE instruction to the scope of the original FOR_ITER instruction, to allow instrumentation.

gh-101967 [https://github.com/python/cpython/issues/101967]: Fix possible segfault in positional_only_passed_as_keyword function, when new list created.

gh-101952 [https://github.com/python/cpython/issues/101952]: Fix possible segfault in BUILD_SET opcode, when new set created.

gh-74895 [https://github.com/python/cpython/issues/74895]: socket.getaddrinfo no longer raises OverflowError for int port values outside of the C long range. Out of range values are left up to the underlying string based C library API to report. A socket.gaierror SAI_SERVICE may occur instead, or no error at all as not all platform C libraries generate an error.

gh-101799 [https://github.com/python/cpython/issues/101799]: Add CALL_INTRINSIC_2 and use it instead of PREP_RERAISE_STAR.

gh-101857 [https://github.com/python/cpython/issues/101857]: Fix xattr support detection on Linux systems by widening the check to linux, not just glibc. This fixes support for musl.

gh-84783 [https://github.com/python/cpython/issues/84783]: Make the slice object hashable. Patch by Will Bradshaw and Furkan Onder.

gh-87849 [https://github.com/python/cpython/issues/87849]: Change the SEND instruction to leave the receiver on the stack. This allows the specialized form of SEND to skip the chain of C calls and jump directly to the RESUME in the generator or coroutine.

gh-101765 [https://github.com/python/cpython/issues/101765]: Fix SystemError / segmentation fault in iter __reduce__ when internal access of builtins.__dict__ keys mutates the iter object.

gh-101430 [https://github.com/python/cpython/issues/101430]: Update tracemalloc to handle presize of object properly. Patch by Donghee Na.

gh-101696 [https://github.com/python/cpython/issues/101696]: Invalidate type version tag in _PyStaticType_Dealloc for static types, avoiding bug where a false cache hit could crash the interpreter. Patch by Kumar Aditya.

gh-101632 [https://github.com/python/cpython/issues/101632]: Adds a new RETURN_CONST instruction.

gh-100719 [https://github.com/python/cpython/issues/100719]: Remove gi_code field from generator (and coroutine and async generator) objects as it is redundant. The frame already includes a reference to the code object.

gh-98627 [https://github.com/python/cpython/issues/98627]: When an interpreter is configured to check (and only then), importing an extension module will now fail when the extension does not support multiple interpreters (i.e. doesn’t implement PEP 489 multi-phase init). This does not apply to the main interpreter, nor to subinterpreters created with Py_NewInterpreter().

Library

gh-102302 [https://github.com/python/cpython/issues/102302]: Micro-optimise hashing of inspect.Parameter, reducing the time it takes to hash an instance by around 40%.

gh-101979 [https://github.com/python/cpython/issues/101979]: Fix a bug where parentheses in the metavar argument to argparse.ArgumentParser.add_argument() were dropped. Patch by Yeojin Kim.

gh-91038 [https://github.com/python/cpython/issues/91038]: platform.platform() now has boolean default arguments.

gh-81652 [https://github.com/python/cpython/issues/81652]: Add mmap.MAP_ALIGNED_SUPER FreeBSD and mmap.MAP_CONCEAL OpenBSD constants to mmap. Patch by Yeojin Kim.

gh-102179 [https://github.com/python/cpython/issues/102179]: Fix os.dup2() error message for negative fds.

gh-101961 [https://github.com/python/cpython/issues/101961]: For the binary mode, fileinput.hookcompressed() doesn’t set the encoding value even if the value is None. Patch by Gihwan Kim.

gh-101936 [https://github.com/python/cpython/issues/101936]: The default value of fp becomes io.BytesIO if HTTPError is initialized without a designated fp parameter. Patch by Long Vo.

gh-101566 [https://github.com/python/cpython/issues/101566]: In zipfile, sync Path with zipp 3.14 [https://zipp.readthedocs.io/en/latest/history.html#v3-14-0], including fix for extractall on the underlying zipfile after being wrapped in Path.

gh-97930 [https://github.com/python/cpython/issues/97930]: Apply changes from importlib_resources 5.12 [https://importlib-resources.readthedocs.io/en/latest/history.html#v5-12-0], including fix for MultiplexedPath to support directories in multiple namespaces (python/importlib_resources#265).

gh-101997 [https://github.com/python/cpython/issues/101997]: Upgrade pip wheel bundled with ensurepip (pip 23.0.1)

gh-99108 [https://github.com/python/cpython/issues/99108]: The built-in extension modules for hashlib SHA2 algorithms, used when OpenSSL does not provide them, now live in a single internal _sha2 module instead of separate _sha256 and _sha512 modules.

gh-101892 [https://github.com/python/cpython/issues/101892]: Callable iterators no longer raise SystemError when the callable object exhausts the iterator but forgets to either return a sentinel value or raise StopIteration.

gh-87634 [https://github.com/python/cpython/issues/87634]: Remove locking behavior from functools.cached_property().

gh-97786 [https://github.com/python/cpython/issues/97786]: Fix potential undefined behaviour in corner cases of floating-point-to-time conversions.

gh-101517 [https://github.com/python/cpython/issues/101517]: Fixed bug where bdb looks up the source line with linecache with a lineno=None, which causes it to fail with an unhandled exception.

gh-101773 [https://github.com/python/cpython/issues/101773]: Optimize fractions.Fraction for small components. The private argument _normalize of the fractions.Fraction constructor has been removed.

gh-101693 [https://github.com/python/cpython/issues/101693]: In sqlite3.Cursor.execute(), DeprecationWarning is now emitted when named placeholders are used together with parameters supplied as a sequence instead of as a dict. Starting from Python 3.14, using named placeholders with parameters supplied as a sequence will raise a ProgrammingError. Patch by Erlend E. Aasland.

gh-101446 [https://github.com/python/cpython/issues/101446]: Change repr of collections.OrderedDict to use regular dictionary formatting instead of pairs of keys and values.

gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.PurePath construction by handling arguments more uniformly. When a pathlib.Path argument is supplied, we use its string representation rather than joining its parts with os.path.join().

gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.PurePath construction by calling os.path.join() only when two or more arguments are given.

gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.Path construction by running the path flavour compatibility check only when pathlib is imported.

gh-85984 [https://github.com/python/cpython/issues/85984]: Refactored the implementation of pty.fork() to use os.login_tty().

A DeprecationWarning is now raised by pty.master_open() and pty.slave_open(). They were undocumented and deprecated long long ago in the docstring in favor of pty.openpty().

gh-101561 [https://github.com/python/cpython/issues/101561]: Add a new decorator typing.override(). See PEP 698 [https://peps.python.org/pep-0698/] for details. Patch by Steven Troxler.

gh-63301 [https://github.com/python/cpython/issues/63301]: Set exit code when tabnanny CLI exits on error.

gh-101360 [https://github.com/python/cpython/issues/101360]: Fix anchor matching in pathlib.PureWindowsPath.match(). Path and pattern anchors are now matched with fnmatch, just like other path parts. This allows patterns such as "*:/Users/*" to be matched.

gh-101277 [https://github.com/python/cpython/issues/101277]: Remove global state from itertools module (PEP 687 [https://peps.python.org/pep-0687/]). Patches by Erlend E. Aasland.

gh-100809 [https://github.com/python/cpython/issues/100809]: Fix handling of drive-relative paths (like ‘C:’ and ‘C:foo’) in pathlib.Path.absolute(). This method now uses the OS API to retrieve the correct current working directory for the drive.

gh-99138 [https://github.com/python/cpython/issues/99138]: Apply PEP 687 [https://peps.python.org/pep-0687/] to zoneinfo. Patch by Erlend E. Aasland.

gh-96764 [https://github.com/python/cpython/issues/96764]: asyncio.wait_for() now uses asyncio.timeout() as its underlying implementation. Patch by Kumar Aditya.

gh-88233 [https://github.com/python/cpython/issues/88233]: Correctly preserve “extra” fields in zipfile regardless of their ordering relative to a zip64 “extra.”

bpo-23224 [https://bugs.python.org/issue?@action=redirect&bpo=23224]: Fix segfaults when creating lzma.LZMADecompressor and bz2.BZ2Decompressor objects without calling __init__(), and fix leakage of locks and internal buffers when calling the __init__() methods of lzma.LZMADecompressor, lzma.LZMACompressor, bz2.BZ2Compressor, and bz2.BZ2Decompressor objects multiple times.

Documentation

gh-85417 [https://github.com/python/cpython/issues/85417]: Update cmath documentation to clarify behaviour on branch cuts.

gh-97725 [https://github.com/python/cpython/issues/97725]: Fix asyncio.Task.print_stack() description for file=None. Patch by Oleg Iarygin.

Tests

gh-102019 [https://github.com/python/cpython/issues/102019]: Fix deadlock on shutdown if test_current_{exception,frames} fails. Patch by Jacob Bower.

gh-85984 [https://github.com/python/cpython/issues/85984]: Utilize new “winsize” functions from termios in pty tests.

gh-89792 [https://github.com/python/cpython/issues/89792]: test_tools now copies up to 10x less source data to a temporary directory during the freeze test by ignoring git metadata and other artifacts. It also limits its python build parallelism based on os.cpu_count instead of hard coding it as 8 cores.

Build

gh-99942 [https://github.com/python/cpython/issues/99942]: On Android, in a static build, python-config in embed mode no longer incorrectly reports a library to link to.

gh-99942 [https://github.com/python/cpython/issues/99942]: On Android, python.pc now correctly reports the library to link to, the same as python-config.sh.

gh-100221 [https://github.com/python/cpython/issues/100221]: Fix creating install directories in make sharedinstall if they exist outside DESTDIR already.

gh-96821 [https://github.com/python/cpython/issues/96821]: Explicitly mark C extension modules that need defined signed integer overflow, and add a configure option --with-strict-overflow. Patch by Matthias Görgens and Shantanu Jain.

Windows

gh-102344 [https://github.com/python/cpython/issues/102344]: Implement winreg.QueryValue using QueryValueEx and winreg.SetValue using SetValueEx. Patch by Max Bachmann.

gh-101881 [https://github.com/python/cpython/issues/101881]: Handle read and write operations on non-blocking pipes properly on Windows.

gh-101881 [https://github.com/python/cpython/issues/101881]: Add support for the os.get_blocking() and os.set_blocking() functions on Windows.

gh-101849 [https://github.com/python/cpython/issues/101849]: Ensures installer will correctly upgrade existing py.exe launcher installs.

gh-101763 [https://github.com/python/cpython/issues/101763]: Updates copy of libffi bundled with Windows installs to 3.4.4.

gh-101759 [https://github.com/python/cpython/issues/101759]: Update Windows installer to SQLite 3.40.1.

gh-101614 [https://github.com/python/cpython/issues/101614]: Correctly handle extensions built against debug binaries that reference python3_d.dll.

gh-101196 [https://github.com/python/cpython/issues/101196]: The functions os.path.isdir, os.path.isfile, os.path.islink and os.path.exists are now 13% to 28% faster on Windows, by making fewer Win32 API calls.

macOS

gh-101759 [https://github.com/python/cpython/issues/101759]: Update macOS installer to SQLite 3.40.1.

C API

gh-101907 [https://github.com/python/cpython/issues/101907]: Removes use of non-standard C++ extension in public header files.

gh-99293 [https://github.com/python/cpython/issues/99293]: Document that the Py_TPFLAGS_VALID_VERSION_TAG is an internal feature, should not be used, and will be removed.

gh-101578 [https://github.com/python/cpython/issues/101578]: Add PyErr_GetRaisedException() and PyErr_SetRaisedException() for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecated PyErr_Fetch() and PyErr_Restore(). This is less error prone and a bit more efficient.

Add PyException_GetArgs() and PyException_SetArgs() as convenience functions for retrieving and modifying the args passed to the exception’s constructor.

gh-91744 [https://github.com/python/cpython/issues/91744]: Introduced the Unstable C API tier, marking APi that is allowed to change in minor releases without a deprecation period. See PEP 689 [https://peps.python.org/pep-0689/] for details.

Python 3.12.0 alpha 5

Release date: 2023-02-07

Security

gh-99108 [https://github.com/python/cpython/issues/99108]: Replace the builtin hashlib implementations of SHA2-224 and SHA2-256 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* [https://github.com/hacl-star/hacl-star/] project. The builtins remain a fallback only used when OpenSSL does not provide them.

Core and Builtins

gh-92173 [https://github.com/python/cpython/issues/92173]: Fix the defs and kwdefs arguments to PyEval_EvalCodeEx() and a reference leak in that function.

gh-59956 [https://github.com/python/cpython/issues/59956]: The GILState API is now partially compatible with subinterpreters. Previously, PyThreadState_GET() and PyGILState_GetThisThreadState() would get out of sync, causing inconsistent behavior and crashes.

gh-101400 [https://github.com/python/cpython/issues/101400]: Fix wrong lineno in exception message on continue or break which are not in a loop. Patch by Donghee Na.

gh-101372 [https://github.com/python/cpython/issues/101372]: Fix is_normalized() to properly handle the UCD 3.2.0 cases. Patch by Donghee Na.

gh-101266 [https://github.com/python/cpython/issues/101266]: Fix sys.getsizeof() reporting for int subclasses.

gh-101291 [https://github.com/python/cpython/issues/101291]: Refactor the PyLongObject struct into a normal Python object header and a PyLongValue struct.

gh-101046 [https://github.com/python/cpython/issues/101046]: Fix a possible memory leak in the parser when raising MemoryError. Patch by Pablo Galindo

gh-101037 [https://github.com/python/cpython/issues/101037]: Fix potential memory underallocation issue for instances of int subclasses with value zero.

gh-100762 [https://github.com/python/cpython/issues/100762]: Record the (virtual) exception block depth in the oparg of YIELD_VALUE. Use this to avoid the expensive throw() when closing generators (and coroutines) that can be closed trivially.

gh-100982 [https://github.com/python/cpython/issues/100982]: Adds a new COMPARE_AND_BRANCH instruction. This is a bit more efficient when performing a comparison immediately followed by a branch, and restores the design intent of PEP 659 that specializations are local to a single instruction.

gh-100942 [https://github.com/python/cpython/issues/100942]: Fixed segfault in property.getter/setter/deleter that occurred when a property subclass overrode the __new__ method to return a non-property instance.

gh-100923 [https://github.com/python/cpython/issues/100923]: Remove the mask cache entry for the COMPARE_OP instruction and embed the mask into the oparg.

gh-100892 [https://github.com/python/cpython/issues/100892]: Fix race while iterating over thread states in clearing threading.local. Patch by Kumar Aditya.

gh-91351 [https://github.com/python/cpython/issues/91351]: Fix a case where re-entrant imports could corrupt the import deadlock detection code and cause a KeyError to be raised out of importlib/_bootstrap. In addition to the straightforward cases, this could also happen when garbage collection leads to a warning being emitted – as happens when it collects an open socket or file)

gh-100726 [https://github.com/python/cpython/issues/100726]: Optimize construction of range object for medium size integers.

gh-100712 [https://github.com/python/cpython/issues/100712]: Added option to build cpython with specialization disabled, by setting ENABLE_SPECIALIZATION=False in opcode, followed by make regen-all.

bpo-32780 [https://bugs.python.org/issue?@action=redirect&bpo=32780]: Inter-field padding is now inserted into the PEP3118 format strings obtained from ctypes.Structure objects, reflecting their true representation in memory.

Library

gh-101541 [https://github.com/python/cpython/issues/101541]: [Enum] - fix psuedo-flag creation

gh-101570 [https://github.com/python/cpython/issues/101570]: Upgrade pip wheel bundled with ensurepip (pip 23.0)

gh-101323 [https://github.com/python/cpython/issues/101323]: Fix a bug where errors where not thrown by zlib._ZlibDecompressor if encountered during decompressing.

gh-101317 [https://github.com/python/cpython/issues/101317]: Add ssl_shutdown_timeout parameter for asyncio.StreamWriter.start_tls().

gh-101326 [https://github.com/python/cpython/issues/101326]: Fix regression when passing None as second or third argument to FutureIter.throw.

gh-92123 [https://github.com/python/cpython/issues/92123]: Adapt the _elementtree extension module to multi-phase init (PEP 489 [https://peps.python.org/pep-0489/]). Patches by Erlend E. Aasland.

gh-100795 [https://github.com/python/cpython/issues/100795]: Avoid potential unexpected freeaddrinfo call (double free) in socket when when a libc getaddrinfo() implementation leaves garbage in an output pointer when returning an error. Original patch by Sergey G. Brester.

gh-101143 [https://github.com/python/cpython/issues/101143]: Remove unused references to TimerHandle in asyncio.base_events.BaseEventLoop._add_callback.

gh-101144 [https://github.com/python/cpython/issues/101144]: Make zipfile.Path.open() and zipfile.Path.read_text() also accept encoding as a positional argument. This was the behavior in Python 3.9 and earlier. 3.10 introduced a regression where supplying it as a positional argument would lead to a TypeError.

gh-94518 [https://github.com/python/cpython/issues/94518]: Group-related variables of _posixsubprocess module are renamed to stress that supplementary group affinity is added to a fork, not replace the inherited ones. Patch by Oleg Iarygin.

gh-101015 [https://github.com/python/cpython/issues/101015]: Fix typing.get_type_hints() on '*tuple[...]' and *tuple[...]. It must not drop the Unpack part.

gh-101000 [https://github.com/python/cpython/issues/101000]: Add os.path.splitroot(), which splits a path into a 3-item tuple (drive, root, tail). This new function is used by pathlib to improve the performance of path construction by up to a third.

gh-100573 [https://github.com/python/cpython/issues/100573]: Fix a Windows asyncio bug with named pipes where a client doing os.stat() on the pipe would cause an error in the server that disabled serving future requests.

gh-39615 [https://github.com/python/cpython/issues/39615]: warnings.warn() now has the ability to skip stack frames based on code filename prefix rather than only a numeric stacklevel via the new skip_file_prefixes keyword argument.

gh-100750 [https://github.com/python/cpython/issues/100750]: pass encoding kwarg to subprocess in platform

gh-100160 [https://github.com/python/cpython/issues/100160]: Emit a deprecation warning in asyncio.DefaultEventLoopPolicy.get_event_loop() if there is no current event loop set and it decides to create one.

gh-96290 [https://github.com/python/cpython/issues/96290]: Fix handling of partial and invalid UNC drives in ntpath.splitdrive(), and in ntpath.normpath() on non-Windows systems. Paths such as ‘\server’ and ‘\’ are now considered by splitdrive() to contain only a drive, and consequently are not modified by normpath() on non-Windows systems. The behaviour of normpath() on Windows systems is unaffected, as native OS APIs are used. Patch by Eryk Sun, with contributions by Barney Gale.

gh-99952 [https://github.com/python/cpython/issues/99952]: Fix a reference undercounting issue in ctypes.Structure with from_param() results larger than a C pointer.

gh-67790 [https://github.com/python/cpython/issues/67790]: Add float-style formatting support for fractions.Fraction instances.

gh-99266 [https://github.com/python/cpython/issues/99266]: Preserve more detailed error messages in ctypes.

gh-86682 [https://github.com/python/cpython/issues/86682]: Ensure runtime-created collections have the correct module name using the newly added (internal) sys._getframemodulename().

gh-88597 [https://github.com/python/cpython/issues/88597]: uuid now has a command line interface. Try python -m uuid -h.

gh-60580 [https://github.com/python/cpython/issues/60580]: ctypes.wintypes.BYTE definition changed from c_byte to c_ubyte to match Windows SDK. Patch by Anatoly Techtonik and Oleg Iarygin.

gh-94518 [https://github.com/python/cpython/issues/94518]: _posixsubprocess now initializes all UID and GID variables using a reserved -1 value instead of a separate flag. Patch by Oleg Iarygin.

bpo-38941 [https://bugs.python.org/issue?@action=redirect&bpo=38941]: The xml.etree.ElementTree module now emits DeprecationWarning when testing the truth value of an xml.etree.ElementTree.Element. Before, the Python implementation emitted FutureWarning, and the C implementation emitted nothing.

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert elementtree types to heap types. Patch by Erlend E. Aasland.

bpo-29847 [https://bugs.python.org/issue?@action=redirect&bpo=29847]: Fix a bug where pathlib.Path accepted and ignored keyword arguments. Patch provided by Yurii Karabas.

gh-77772 [https://github.com/python/cpython/issues/77772]: ctypes.CDLL, ctypes.OleDLL, ctypes.WinDLL, and ctypes.PyDLL now accept path-like objects as their name argument. Patch by Robert Hoelzl.

Documentation

gh-88324 [https://github.com/python/cpython/issues/88324]: Reword subprocess to emphasize default behavior of stdin, stdout, and stderr arguments. Remove inaccurate statement about child file handle inheritance.

Tests

gh-101334 [https://github.com/python/cpython/issues/101334]: test_tarfile has been updated to pass when run as a high UID.

Build

gh-101282 [https://github.com/python/cpython/issues/101282]: Update BOLT configuration not to use deprecated usage of --split functions. Patch by Donghee Na.

gh-101522 [https://github.com/python/cpython/issues/101522]: Allow overriding Windows dependencies versions and paths using MSBuild properties.

gh-77532 [https://github.com/python/cpython/issues/77532]: Minor fixes to allow building with PlatformToolset=ClangCL on Windows.

gh-101152 [https://github.com/python/cpython/issues/101152]: In accordance with PEP 699 [https://peps.python.org/pep-0699/], the ma_version_tag field in PyDictObject is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14.

gh-100340 [https://github.com/python/cpython/issues/100340]: Allows -Wno-int-conversion for wasm-sdk 17 and onwards, thus enables building WASI builds once against the latest sdk.

gh-101060 [https://github.com/python/cpython/issues/101060]: Conditionally add -fno-reorder-blocks-and-partition in configure. Effectively fixes --enable-bolt when using Clang, as this appears to be a GCC-only flag.

gh-98705 [https://github.com/python/cpython/issues/98705]: __bool__ is defined in AIX system header files which breaks the build in AIX, so undefine it.

gh-98636 [https://github.com/python/cpython/issues/98636]: Fix a regression in detecting gdbm_compat library for the _gdbm module build.

gh-96305 [https://github.com/python/cpython/issues/96305]: _aix_support now uses a simple code to get platform details rather than the now non-existent _bootsubprocess during bootstrap.

Windows

gh-101543 [https://github.com/python/cpython/issues/101543]: Ensure the install path in the registry is only used when the standard library hasn’t been located in any other way.

gh-101467 [https://github.com/python/cpython/issues/101467]: The py.exe launcher now correctly filters when only a single runtime is installed. It also correctly handles prefix matches on tags so that -3.1 does not match 3.11, but would still match 3.1-32.

gh-99834 [https://github.com/python/cpython/issues/99834]: Updates bundled copy of Tcl/Tk to 8.6.13.0

gh-101135 [https://github.com/python/cpython/issues/101135]: Restore ability to launch older 32-bit versions from the py.exe launcher when both 32-bit and 64-bit installs of the same version are available.

gh-82052 [https://github.com/python/cpython/issues/82052]: Fixed an issue where writing more than 32K of Unicode output to the console screen in one go can result in mojibake.

gh-100320 [https://github.com/python/cpython/issues/100320]: Ensures the PythonPath registry key from an install is used when launching from a different copy of Python that relies on an existing install to provide a copy of its modules and standard library.

gh-100247 [https://github.com/python/cpython/issues/100247]: Restores support for the py.exe launcher finding shebang commands in its configuration file using the full command name.

Python 3.12.0 alpha 4

Release date: 2023-01-10

Core and Builtins

gh-100776 [https://github.com/python/cpython/issues/100776]: Fix misleading default value in input()’s __text_signature__.

gh-99005 [https://github.com/python/cpython/issues/99005]: Remove UNARY_POSITIVE, ASYNC_GEN_WRAP and LIST_TO_TUPLE, replacing them with intrinsics.

gh-99005 [https://github.com/python/cpython/issues/99005]: Add new CALL_INTRINSIC_1 instruction. Remove IMPORT_STAR, PRINT_EXPR and STOPITERATION_ERROR, replacing them with the CALL_INTRINSIC_1 instruction.

gh-100288 [https://github.com/python/cpython/issues/100288]: Remove the LOAD_ATTR_METHOD_WITH_DICT specialized instruction. Stats show it is not useful.

gh-100720 [https://github.com/python/cpython/issues/100720]: Added _PyFrame_NumSlotsForCodeObject, which returns the number of slots needed in a frame for a given code object.

gh-100719 [https://github.com/python/cpython/issues/100719]: Removed the co_nplaincellvars field from the code object, as it is redundant.

gh-100637 [https://github.com/python/cpython/issues/100637]: Fix int.__sizeof__() calculation to include the 1-element ob_digit array for 0 and False.

gh-100649 [https://github.com/python/cpython/issues/100649]: Update the native_thread_id field of PyThreadState after fork.

gh-100126 [https://github.com/python/cpython/issues/100126]: Fix an issue where “incomplete” frames could be briefly visible to C code while other frames are being torn down, possibly resulting in corruption or hard crashes of the interpreter while running finalizers.

gh-87447 [https://github.com/python/cpython/issues/87447]: Fix SyntaxError on comprehension rebind checking with names that are not actually redefined.

Now reassigning b in [(b := 1) for a, b.prop in some_iter] is allowed. Reassigning a is still disallowed as per PEP 572 [https://peps.python.org/pep-0572/].

gh-100268 [https://github.com/python/cpython/issues/100268]: Add int.is_integer() to improve duck type compatibility between int and float.

gh-100425 [https://github.com/python/cpython/issues/100425]: Improve the accuracy of sum() with compensated summation.

gh-100374 [https://github.com/python/cpython/issues/100374]: Fix incorrect result and delay in socket.getfqdn(). Patch by Dominic Socular.

gh-100357 [https://github.com/python/cpython/issues/100357]: Convert vars, dir, next, getattr, and iter to argument clinic.

gh-100117 [https://github.com/python/cpython/issues/100117]: Improve the output of codeobject.co_lines() by emitting only one entry for each line range.

gh-90043 [https://github.com/python/cpython/issues/90043]: Handle NaNs when specializing COMPARE_OP for float values.

gh-100222 [https://github.com/python/cpython/issues/100222]: Redefine the _Py_CODEUNIT typedef as a union to describe its layout to the C compiler, avoiding type punning and improving clarity.

gh-99955 [https://github.com/python/cpython/issues/99955]: Internal compiler functions (in compile.c) now consistently return -1 on error and 0 on success.

gh-100188 [https://github.com/python/cpython/issues/100188]: The BINARY_SUBSCR_LIST_INT and BINARY_SUBSCR_TUPLE_INT instructions are no longer used for negative integers because those instructions always miss when encountering negative integers.

gh-99110 [https://github.com/python/cpython/issues/99110]: Initialize frame->previous in frameobject.c to fix a segmentation fault when accessing frames created by PyFrame_New().

gh-94155 [https://github.com/python/cpython/issues/94155]: Improved the hashing algorithm for code objects, mitigating some hash collisions.

gh-99540 [https://github.com/python/cpython/issues/99540]: None now hashes to a constant value. This is not a requirements change.

gh-100143 [https://github.com/python/cpython/issues/100143]: When built with --enable-pystats, stats collection is now off by default. To enable it early at startup, pass the -Xpystats flag. Stats are now always dumped, even if switched off.

gh-100146 [https://github.com/python/cpython/issues/100146]: Improve BUILD_LIST opcode so that it works similarly to the BUILD_TUPLE opcode, by stealing references from the stack rather than repeatedly using stack operations to set list elements. Implementation details are in a new private API _PyList_FromArraySteal().

gh-100110 [https://github.com/python/cpython/issues/100110]: Specialize FOR_ITER for tuples.

gh-100050 [https://github.com/python/cpython/issues/100050]: Honor existing errors obtained when searching for mismatching parentheses in the tokenizer. Patch by Pablo Galindo

gh-92216 [https://github.com/python/cpython/issues/92216]: Improve the performance of hasattr() for type objects with a missing attribute.

gh-99582 [https://github.com/python/cpython/issues/99582]: Freeze zipimport module into _bootstrap_python.

gh-99554 [https://github.com/python/cpython/issues/99554]: Pack debugging location tables more efficiently during bytecode compilation.

gh-98522 [https://github.com/python/cpython/issues/98522]: Add an internal version number to code objects, to give better versioning of inner functions and comprehensions, and thus better specialization of those functions. This change is invisible to both Python and C extensions.

gh-94603 [https://github.com/python/cpython/issues/94603]: Improve performance of list.pop for small lists.

gh-89051 [https://github.com/python/cpython/issues/89051]: Add ssl.OP_LEGACY_SERVER_CONNECT

bpo-32782 [https://bugs.python.org/issue?@action=redirect&bpo=32782]: ctypes arrays of length 0 now report a correct itemsize when a memoryview is constructed from them, rather than always giving a value of 0.

Library

gh-100833 [https://github.com/python/cpython/issues/100833]: Speed up math.fsum() by removing defensive volatile qualifiers.

gh-100805 [https://github.com/python/cpython/issues/100805]: Modify random.choice() implementation to once again work with NumPy arrays.

gh-100813 [https://github.com/python/cpython/issues/100813]: Add socket.IP_PKTINFO constant.

gh-100792 [https://github.com/python/cpython/issues/100792]: Make email.message.Message.__contains__() twice as fast.

gh-91851 [https://github.com/python/cpython/issues/91851]: Microoptimizations for fractions.Fraction.__round__(), fractions.Fraction.__ceil__() and fractions.Fraction.__floor__().

gh-90104 [https://github.com/python/cpython/issues/90104]: Avoid RecursionError on repr if a dataclass field definition has a cyclic reference.

gh-100689 [https://github.com/python/cpython/issues/100689]: Fix crash in pyexpat by statically allocating PyExpat_CAPI capsule.

gh-100740 [https://github.com/python/cpython/issues/100740]: Fix unittest.mock.Mock not respecting the spec for attribute names prefixed with assert.

gh-91219 [https://github.com/python/cpython/issues/91219]: Change SimpleHTTPRequestHandler to support subclassing to provide a different set of index file names instead of using __init__ parameters.

gh-100690 [https://github.com/python/cpython/issues/100690]: Mock objects which are not unsafe will now raise an AttributeError when accessing an attribute that matches the name of an assertion but without the prefix assert_, e.g. accessing called_once instead of assert_called_once. This is in addition to this already happening for accessing attributes with prefixes assert, assret, asert, aseert, and assrt.

gh-89727 [https://github.com/python/cpython/issues/89727]: Simplify and optimize os.walk() by using isinstance() checks to check the top of the stack.

gh-100485 [https://github.com/python/cpython/issues/100485]: Add math.sumprod() to compute the sum of products.

gh-86508 [https://github.com/python/cpython/issues/86508]: Fix asyncio.open_connection() to skip binding to local addresses of different family. Patch by Kumar Aditya.

gh-97930 [https://github.com/python/cpython/issues/97930]: importlib.resources.files now accepts a module as an anchor instead of only accepting packages. If a module is passed, resources are resolved adjacent to that module (in the same package or at the package root). The parameter was renamed from package to anchor with a compatibility shim for those passing by keyword. Additionally, the new anchor parameter is now optional and will default to the caller’s module.

gh-100585 [https://github.com/python/cpython/issues/100585]: Fixed a bug where importlib.resources.as_file was leaving file pointers open

gh-100562 [https://github.com/python/cpython/issues/100562]: Improve performance of pathlib.Path.absolute() by nearly 2x. This comes at the cost of a performance regression in pathlib.Path.cwd(), which is generally used less frequently in user code.

gh-100519 [https://github.com/python/cpython/issues/100519]: Small simplification of http.cookiejar.eff_request_host() that improves readability and better matches the RFC wording.

gh-100287 [https://github.com/python/cpython/issues/100287]: Fix the interaction of unittest.mock.seal() with unittest.mock.AsyncMock.

gh-100488 [https://github.com/python/cpython/issues/100488]: Add Fraction.is_integer() to check whether a fractions.Fraction is an integer. This improves duck type compatibility with float and int.

gh-100474 [https://github.com/python/cpython/issues/100474]: http.server now checks that an index page is actually a regular file before trying to serve it. This avoids issues with directories named index.html.

gh-100363 [https://github.com/python/cpython/issues/100363]: Speed up asyncio.get_running_loop() by removing redundant getpid checks. Patch by Kumar Aditya.

gh-78878 [https://github.com/python/cpython/issues/78878]: Fix crash when creating an instance of _ctypes.CField.

gh-100348 [https://github.com/python/cpython/issues/100348]: Fix ref cycle in asyncio._SelectorSocketTransport by removing _read_ready_cb in close.

gh-100344 [https://github.com/python/cpython/issues/100344]: Provide C implementation for asyncio.current_task() for a 4x-6x speedup.

gh-100272 [https://github.com/python/cpython/issues/100272]: Fix JSON serialization of OrderedDict. It now preserves the order of keys.

gh-83076 [https://github.com/python/cpython/issues/83076]: Instantiation of Mock() and AsyncMock() is now 3.8x faster.

gh-100234 [https://github.com/python/cpython/issues/100234]: Set a default value of 1.0 for the lambd parameter in random.expovariate().

gh-100228 [https://github.com/python/cpython/issues/100228]: A DeprecationWarning may be raised when os.fork() or os.forkpty() is called from multi-threaded processes. Forking with threads is unsafe and can cause deadlocks, crashes and subtle problems. Lack of a warning does not indicate that the fork call was actually safe, as Python may not be aware of all threads.

gh-100039 [https://github.com/python/cpython/issues/100039]: Improve signatures for enums and flags.

gh-100133 [https://github.com/python/cpython/issues/100133]: Fix regression in asyncio where a subprocess would sometimes lose data received from pipe.

bpo-44592 [https://bugs.python.org/issue?@action=redirect&bpo=44592]: Fixes inconsistent handling of case sensitivity of extrasaction arg in csv.DictWriter.

gh-100098 [https://github.com/python/cpython/issues/100098]: Fix tuple subclasses being cast to tuple when used as enum values.

gh-85432 [https://github.com/python/cpython/issues/85432]: Rename the fmt parameter of the pure-Python implementation of datetime.time.strftime() to format. Rename the t parameter of datetime.datetime.fromtimestamp() to timestamp. These changes mean the parameter names in the pure-Python implementation now match the parameter names in the C implementation. Patch by Alex Waygood.

gh-98778 [https://github.com/python/cpython/issues/98778]: Update HTTPError to be initialized properly, even if the fp is None. Patch by Donghee Na.

gh-99925 [https://github.com/python/cpython/issues/99925]: Unify error messages in JSON serialization between json.dumps(float('nan'), allow_nan=False) and json.dumps(float('nan'), allow_nan=False, indent=<SOMETHING>). Now both include the representation of the value that could not be serialized.

gh-89727 [https://github.com/python/cpython/issues/89727]: Fix issue with os.walk() where a RecursionError would occur on deep directory structures by adjusting the implementation of os.walk() to be iterative instead of recursive.

gh-94943 [https://github.com/python/cpython/issues/94943]: Add Dataclass support to the Enum __repr__(). When inheriting from a dataclass, only show the field names in the value section of the member repr(), and not the dataclass’ class name.

gh-83035 [https://github.com/python/cpython/issues/83035]: Fix inspect.getsource() handling of decorator calls with nested parentheses.

gh-99576 [https://github.com/python/cpython/issues/99576]: Fix .save() method for LWPCookieJar and MozillaCookieJar: saved file was not truncated on repeated save.

gh-94912 [https://github.com/python/cpython/issues/94912]: Add inspect.markcoroutinefunction() decorator which manually marks a function as a coroutine for the benefit of iscoroutinefunction().

gh-99509 [https://github.com/python/cpython/issues/99509]: Add PEP 585 [https://peps.python.org/pep-0585/] support for multiprocessing.queues.Queue.

gh-99482 [https://github.com/python/cpython/issues/99482]: Remove Jython partial compatibility code from several stdlib modules.

gh-99433 [https://github.com/python/cpython/issues/99433]: Fix doctest failure on types.MethodWrapperType in modules.

gh-85267 [https://github.com/python/cpython/issues/85267]: Several improvements to inspect.signature()’s handling of __text_signature. - Fixes a case where inspect.signature() dropped parameters - Fixes a case where inspect.signature() raised tokenize.TokenError - Allows inspect.signature() to understand defaults involving binary operations of constants - inspect.signature() is documented as only raising TypeError or ValueError, but sometimes raised RuntimeError. These cases now raise ValueError - Removed a dead code path

gh-91166 [https://github.com/python/cpython/issues/91166]: asyncio is optimized to avoid excessive copying when writing to socket and use sendmsg() if the platform supports it. Patch by Kumar Aditya.

gh-98030 [https://github.com/python/cpython/issues/98030]: Add missing TCP socket options from Linux: TCP_MD5SIG, TCP_THIN_LINEAR_TIMEOUTS, TCP_THIN_DUPACK, TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS, TCP_TIMESTAMP, TCP_CC_INFO, TCP_SAVE_SYN, TCP_SAVED_SYN, TCP_REPAIR_WINDOW, TCP_FASTOPEN_CONNECT, TCP_ULP, TCP_MD5SIG_EXT, TCP_FASTOPEN_KEY, TCP_FASTOPEN_NO_COOKIE, TCP_ZEROCOPY_RECEIVE, TCP_INQ, TCP_TX_DELAY.

gh-88500 [https://github.com/python/cpython/issues/88500]: Reduced the memory usage of urllib.parse.unquote() and urllib.parse.unquote_to_bytes() on large values.

gh-96127 [https://github.com/python/cpython/issues/96127]: inspect.signature was raising TypeError on call with mock objects. Now it correctly returns (*args, **kwargs) as inferred signature.

gh-95882 [https://github.com/python/cpython/issues/95882]: Fix a 3.11 regression in asynccontextmanager(), which caused it to propagate exceptions with incorrect tracebacks and fix a 3.11 regression in contextmanager(), which caused it to propagate exceptions with incorrect tracebacks for StopIteration.

gh-78707 [https://github.com/python/cpython/issues/78707]: Deprecate passing more than one positional argument to pathlib.PurePath.relative_to() and is_relative_to().

gh-92122 [https://github.com/python/cpython/issues/92122]: Fix reStructuredText syntax errors in docstrings in the enum module.

gh-91851 [https://github.com/python/cpython/issues/91851]: Optimize the Fraction arithmetics for small components.

bpo-24132 [https://bugs.python.org/issue?@action=redirect&bpo=24132]: Make pathlib.PurePath and Path subclassable (private to start). Previously, attempting to instantiate a subclass resulted in an AttributeError being raised. Patch by Barney Gale.

bpo-40447 [https://bugs.python.org/issue?@action=redirect&bpo=40447]: Accept os.PathLike (such as pathlib.Path) in the stripdir arguments of compileall.compile_file() and compileall.compile_dir().

bpo-36880 [https://bugs.python.org/issue?@action=redirect&bpo=36880]: Fix a reference counting issue when a ctypes callback with return type py_object returns None, which could cause crashes.

Documentation

gh-100616 [https://github.com/python/cpython/issues/100616]: Document existing attr parameter to curses.window.vline() function in curses.

gh-100472 [https://github.com/python/cpython/issues/100472]: Remove claim in documentation that the stripdir, prependdir and limit_sl_dest parameters of compileall.compile_dir() and compileall.compile_file() could be bytes.

bpo-25377 [https://bugs.python.org/issue?@action=redirect&bpo=25377]: Clarify use of octal format of mode argument in help(os.chmod) as well as help(os.fchmod)

Tests

gh-100454 [https://github.com/python/cpython/issues/100454]: Start running SSL tests with OpenSSL 3.1.0-beta1.

gh-100086 [https://github.com/python/cpython/issues/100086]: The Python test runner (libregrtest) now logs Python build information like “debug” vs “release” build, or LTO and PGO optimizations. Patch by Victor Stinner.

gh-93018 [https://github.com/python/cpython/issues/93018]: Make two tests forgiving towards host system libexpat with backported security fixes applied.

Build

gh-100540 [https://github.com/python/cpython/issues/100540]: Removed the --with-system-ffi configure option; libffi must now always be supplied by the system on all non-Windows platforms. The option has had no effect on non-Darwin platforms for several releases, and in 3.11 only had the non-obvious effect of invoking pkg-config to find libffi and never setting -DUSING_APPLE_OS_LIBFFI. Now on Darwin platforms configure will first check for the OS libffi and then fall back to the same processing as other platforms if it is not found.

gh-88267 [https://github.com/python/cpython/issues/88267]: Avoid exporting Python symbols in linked Windows applications when the core is built as static.

bpo-41916 [https://bugs.python.org/issue?@action=redirect&bpo=41916]: Allow override of ac_cv_cxx_thread so that cross compiled python can set -pthread for CXX.

Windows

gh-100180 [https://github.com/python/cpython/issues/100180]: Update Windows installer to OpenSSL 1.1.1s

gh-99191 [https://github.com/python/cpython/issues/99191]: Use _MSVC_LANG >= 202002L instead of less-precise _MSC_VER >=1929 to more accurately test for C++20 support in PC/_wmimodule.cpp.

gh-79218 [https://github.com/python/cpython/issues/79218]: Define MS_WIN64 for Mingw-w64 64bit, fix cython compilation failure.

gh-99941 [https://github.com/python/cpython/issues/99941]: Ensure that asyncio.Protocol.data_received() receives an immutable bytes object (as documented), instead of bytearray.

bpo-43984 [https://bugs.python.org/issue?@action=redirect&bpo=43984]: winreg.SetValueEx() now leaves the target value untouched in the case of conversion errors. Previously, -1 would be written in case of such errors.

bpo-34816 [https://bugs.python.org/issue?@action=redirect&bpo=34816]: hasattr(ctypes.windll, 'nonexistant') now returns False instead of raising OSError.

macOS

gh-100180 [https://github.com/python/cpython/issues/100180]: Update macOS installer to OpenSSL 1.1.1s

gh-100540 [https://github.com/python/cpython/issues/100540]: Removed obsolete dlfcn.h shim from the _ctypes extension module, which has not been necessary since Mac OS X 10.2.

Tools/Demos

bpo-45256 [https://bugs.python.org/issue?@action=redirect&bpo=45256]: Fix a bug that caused an AttributeError to be raised in python-gdb.py when py-locals is used without a frame.

gh-100342 [https://github.com/python/cpython/issues/100342]: Add missing NULL check for possible allocation failure in *args parsing in Argument Clinic.

C API

gh-99947 [https://github.com/python/cpython/issues/99947]: Raising SystemError on import will now have its cause be set to the original unexpected exception.

gh-99240 [https://github.com/python/cpython/issues/99240]: In argument parsing, after deallocating newly allocated memory, reset its pointer to NULL.

gh-98724 [https://github.com/python/cpython/issues/98724]: The Py_CLEAR, Py_SETREF and Py_XSETREF macros now only evaluate their arguments once. If an argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.

Python 3.12.0 alpha 3

Release date: 2022-12-06

Security

gh-100001 [https://github.com/python/cpython/issues/100001]: python -m http.server no longer allows terminal control characters sent within a garbage request to be printed to the stderr server log.

This is done by changing the http.server BaseHTTPRequestHandler .log_message method to replace control characters with a \xHH hex escape before printing.

gh-87604 [https://github.com/python/cpython/issues/87604]: Avoid publishing list of active per-interpreter audit hooks via the gc module

Core and Builtins

gh-99891 [https://github.com/python/cpython/issues/99891]: Fix a bug in the tokenizer that could cause infinite recursion when showing syntax warnings that happen in the first line of the source. Patch by Pablo Galindo

gh-91054 [https://github.com/python/cpython/issues/91054]: Add PyCode_AddWatcher() and PyCode_ClearWatcher() APIs to register callbacks to receive notification on creation and destruction of code objects.

gh-99729 [https://github.com/python/cpython/issues/99729]: Fix an issue that could cause frames to be visible to Python code as they are being torn down, possibly leading to memory corruption or hard crashes of the interpreter.

gh-99708 [https://github.com/python/cpython/issues/99708]: Fix bug where compiler crashes on an if expression with an empty body block.

gh-99578 [https://github.com/python/cpython/issues/99578]: Fix a reference bug in _imp.create_builtin() after the creation of the first sub-interpreter for modules builtins and sys. Patch by Victor Stinner.

gh-99581 [https://github.com/python/cpython/issues/99581]: Fixed a bug that was causing a buffer overflow if the tokenizer copies a line missing the newline character from a file that is as long as the available tokenizer buffer. Patch by Pablo galindo

gh-99553 [https://github.com/python/cpython/issues/99553]: Fix bug where an ExceptionGroup subclass can wrap a BaseException.

gh-99547 [https://github.com/python/cpython/issues/99547]: Add a function to os.path to check if a path is a junction: isjunction. Add similar functionality to pathlib.Path as is_junction.

gh-99370 [https://github.com/python/cpython/issues/99370]: Fix zip path for venv created from a non-installed python on POSIX platforms.

gh-99377 [https://github.com/python/cpython/issues/99377]: Add audit events for thread creation and clear operations.

gh-98686 [https://github.com/python/cpython/issues/98686]: Remove the BINARY_OP_GENERIC and COMPARE_OP_GENERIC “specializations”.

gh-99298 [https://github.com/python/cpython/issues/99298]: Remove the remaining error paths for attribute specializations, and refuse to specialize attribute accesses on types that haven’t had PyType_Ready() called on them yet.

gh-99127 [https://github.com/python/cpython/issues/99127]: Allow some features of syslog to the main interpreter only. Patch by Donghee Na.

gh-91053 [https://github.com/python/cpython/issues/91053]: Optimizing interpreters and JIT compilers may need to invalidate internal metadata when functions are modified. This change adds the ability to provide a callback that will be invoked each time a function is created, modified, or destroyed.

gh-90994 [https://github.com/python/cpython/issues/90994]: Improve error messages when there’s a syntax error with call arguments. The following three cases are covered: - No value is assigned to a named argument, eg foo(a=). - A value is assigned to a star argument, eg foo(*args=[0]). - A value is assigned to a double-star keyword argument, eg foo(**kwarg={'a': 0}).

bpo-45026 [https://bugs.python.org/issue?@action=redirect&bpo=45026]: Optimize the range object iterator. It is now smaller, faster iteration of ranges containing large numbers. Smaller pickles, faster unpickling.

bpo-31718 [https://bugs.python.org/issue?@action=redirect&bpo=31718]: Raise ValueError instead of SystemError when methods of uninitialized io.IncrementalNewlineDecoder objects are called. Patch by Oren Milman.

bpo-38031 [https://bugs.python.org/issue?@action=redirect&bpo=38031]: Fix a possible assertion failure in io.FileIO when the opener returns an invalid file descriptor.

Library

gh-100001 [https://github.com/python/cpython/issues/100001]: Also escape s in the http.server BaseHTTPRequestHandler.log_message so that it is technically possible to parse the line and reconstruct what the original data was. Without this a xHH is ambiguous as to if it is a hex replacement we put in or the characters r”x” came through in the original request line.

gh-99957 [https://github.com/python/cpython/issues/99957]: Add frozen_default parameter to typing.dataclass_transform().

gh-79033 [https://github.com/python/cpython/issues/79033]: Fix asyncio.Server.wait_closed() to actually do what the docs promise – wait for all existing connections to complete, after closing the server.

gh-51524 [https://github.com/python/cpython/issues/51524]: Fix bug when calling trace.CoverageResults with valid infile.

gh-99645 [https://github.com/python/cpython/issues/99645]: Fix a bug in handling class cleanups in unittest.TestCase. Now addClassCleanup() uses separate lists for different TestCase subclasses, and doClassCleanups() only cleans up the particular class.

gh-99508 [https://github.com/python/cpython/issues/99508]: Fix TypeError in Lib/importlib/_bootstrap_external.py while calling _imp.source_hash().

gh-66285 [https://github.com/python/cpython/issues/66285]: Fix asyncio to not share event loop and signal wakeupfd in forked processes. Patch by Kumar Aditya.

gh-97001 [https://github.com/python/cpython/issues/97001]: Release the GIL when calling termios APIs to avoid blocking threads.

gh-92647 [https://github.com/python/cpython/issues/92647]: Use final status of an enum to determine lookup or creation branch of functional API.

gh-99388 [https://github.com/python/cpython/issues/99388]: Add loop_factory parameter to asyncio.run() to allow specifying a custom event loop factory. Patch by Kumar Aditya.

gh-99341 [https://github.com/python/cpython/issues/99341]: Fix ast.increment_lineno() to also cover ast.TypeIgnore when changing line numbers.

gh-99382 [https://github.com/python/cpython/issues/99382]: Check the number of arguments in substitution in user generics containing a TypeVarTuple and one or more TypeVar.

gh-99379 [https://github.com/python/cpython/issues/99379]: Fix substitution of ParamSpec followed by TypeVarTuple in generic aliases.

gh-99344 [https://github.com/python/cpython/issues/99344]: Fix substitution of TypeVarTuple and ParamSpec together in user generics.

gh-99284 [https://github.com/python/cpython/issues/99284]: Remove _use_broken_old_ctypes_structure_semantics_ old untested and undocumented hack from ctypes.

gh-99201 [https://github.com/python/cpython/issues/99201]: Fix IndexError when initializing the config variables on Windows if HAVE_DYNAMIC_LOADING is not set.

gh-99240 [https://github.com/python/cpython/issues/99240]: Fix double-free bug in Argument Clinic str_converter by extracting memory clean up to a new post_parsing section.

gh-64490 [https://github.com/python/cpython/issues/64490]: Fix refcount error when arguments are packed to tuple in Argument Clinic.

gh-99029 [https://github.com/python/cpython/issues/99029]: pathlib.PurePath.relative_to() now treats naked Windows drive paths as relative. This brings its behaviour in line with other parts of pathlib.

gh-98253 [https://github.com/python/cpython/issues/98253]: The implementation of the typing module is now more resilient to reference leaks in binary extension modules.

Previously, a reference leak in a typed C API-based extension module could leak internals of the typing module, which could in turn introduce leaks in essentially any other package with typed function signatures. Although the typing package is not the original source of the problem, such non-local dependences exacerbate debugging of large-scale projects, and the implementation was therefore changed to reduce harm by providing better isolation.

gh-98458 [https://github.com/python/cpython/issues/98458]: Fix infinite loop in unittest when a self-referencing chained exception is raised

gh-93453 [https://github.com/python/cpython/issues/93453]: asyncio.get_event_loop() and many other asyncio functions like asyncio.ensure_future(), asyncio.shield() or asyncio.gather(), and also the get_event_loop() method of asyncio.BaseDefaultEventLoopPolicy now raise a RuntimeError if called when there is no running event loop and the current event loop was not set. Previously they implicitly created and set a new current event loop. DeprecationWarning is no longer emitted if there is no running event loop but the current event loop was set.

gh-97966 [https://github.com/python/cpython/issues/97966]: On uname_result, restored expectation that _fields and _asdict would include all six properties including processor.

gh-98248 [https://github.com/python/cpython/issues/98248]: Provide informative error messages in struct.pack() when its integral arguments are not in range.

gh-98108 [https://github.com/python/cpython/issues/98108]: zipfile.Path is now pickleable if its initialization parameters were pickleable (e.g. for file system paths).

gh-98098 [https://github.com/python/cpython/issues/98098]: Created packages from zipfile and test_zipfile modules, separating zipfile.Path functionality.

gh-82836 [https://github.com/python/cpython/issues/82836]: Fix is_private properties in the ipaddress module. Previously non-private networks (0.0.0.0/0) would return True from this method; now they correctly return False.

gh-96828 [https://github.com/python/cpython/issues/96828]: Add an OP_ENABLE_KTLS option for enabling the use of the kernel TLS (kTLS). Patch by Illia Volochii.

gh-88863 [https://github.com/python/cpython/issues/88863]: To avoid apparent memory leaks when asyncio.open_connection() raises, break reference cycles generated by local exception and future instances (which has exception instance as its member var). Patch by Dong Uk, Kang.

gh-91078 [https://github.com/python/cpython/issues/91078]: TarFile.next() now returns None when called on an empty tarfile.

bpo-47220 [https://bugs.python.org/issue?@action=redirect&bpo=47220]: Document the optional callback parameter of WeakMethod. Patch by Géry Ogam.

bpo-44817 [https://bugs.python.org/issue?@action=redirect&bpo=44817]: Ignore WinError 53 (ERROR_BAD_NETPATH), 65 (ERROR_NETWORK_ACCESS_DENIED) and 161 (ERROR_BAD_PATHNAME) when using ntpath.realpath().

bpo-41260 [https://bugs.python.org/issue?@action=redirect&bpo=41260]: Rename the fmt parameter of the pure Python implementation of datetime.date.strftime() to format.

bpo-15999 [https://bugs.python.org/issue?@action=redirect&bpo=15999]: All built-in functions now accept arguments of any type instead of just bool and int for boolean parameters.

Documentation

gh-99931 [https://github.com/python/cpython/issues/99931]: Use sphinxext-opengraph [https://sphinxext-opengraph.readthedocs.io/] to generate OpenGraph metadata [https://ogp.me/].

gh-89682 [https://github.com/python/cpython/issues/89682]: Reworded docstring of the default __contains__ to clarify that it returns a bool.

gh-88330 [https://github.com/python/cpython/issues/88330]: Improved the description of what a resource is in importlib.resources docs.

gh-92892 [https://github.com/python/cpython/issues/92892]: Document that calling variadic functions with ctypes requires special care on macOS/arm64 (and possibly other platforms).

bpo-41825 [https://bugs.python.org/issue?@action=redirect&bpo=41825]: Restructured the documentation for the os.wait* family of functions, and improved the docs for os.waitid() with more explanation of the possible argument constants.

Tests

gh-99892 [https://github.com/python/cpython/issues/99892]: Skip test_normalization() of test_unicodedata if it fails to download NormalizationTest.txt file from pythontest.net. Patch by Victor Stinner.

gh-99934 [https://github.com/python/cpython/issues/99934]: Correct test_marsh on (32 bit) x86: test_deterministic sets was failing.

gh-99741 [https://github.com/python/cpython/issues/99741]: We’ve implemented multi-phase init (PEP 489/630/687) for the internal (for testing) _xxsubinterpreters module.

gh-99659 [https://github.com/python/cpython/issues/99659]: Optional big memory tests in test_sqlite3 now catch the correct sqlite.DataError exception type in case of too large strings and/or blobs passed.

gh-99593 [https://github.com/python/cpython/issues/99593]: Cover the Unicode C API with tests.

gh-96002 [https://github.com/python/cpython/issues/96002]: Add functional test for Argument Clinic.

Build

gh-99086 [https://github.com/python/cpython/issues/99086]: Fix -Wimplicit-int, -Wstrict-prototypes, and -Wimplicit-function-declaration compiler warnings in configure checks.

gh-99337 [https://github.com/python/cpython/issues/99337]: Fix a compilation issue with GCC 12 on macOS.

gh-99289 [https://github.com/python/cpython/issues/99289]: Add a COMPILEALL_OPTS variable in Makefile to override compileall options (default: -j0) in make install. Also merged the compileall commands into a single command building .pyc files for the all optimization levels (0, 1, 2) at once. Patch by Victor Stinner.

gh-98872 [https://github.com/python/cpython/issues/98872]: Fix a possible fd leak in Programs/_freeze_module.c introduced in Python 3.11.

gh-88226 [https://github.com/python/cpython/issues/88226]: Always define TARGET_* labels in Python/ceval.c, even if USE_COMPUTED_GOTOS is disabled. This allows breakpoints to be set at those labels in (for instance) gdb.

Windows

gh-99345 [https://github.com/python/cpython/issues/99345]: Use faster initialization functions to detect install location for Windows Store package

gh-98629 [https://github.com/python/cpython/issues/98629]: Fix initialization of sys.version and sys._git on Windows

gh-99442 [https://github.com/python/cpython/issues/99442]: Fix handling in 윈도우 용 파이썬 런처 when argv[0] does not include a file extension.

bpo-40882 [https://bugs.python.org/issue?@action=redirect&bpo=40882]: Fix a memory leak in multiprocessing.shared_memory.SharedMemory on Windows.

macOS

gh-87235 [https://github.com/python/cpython/issues/87235]: On macOS python3 /dev/fd/9 9</path/to/script.py failed for any script longer than a couple of bytes.

gh-98940 [https://github.com/python/cpython/issues/98940]: Fix Mac/Extras.install.py file filter bug.

Tools/Demos

gh-64490 [https://github.com/python/cpython/issues/64490]: Argument Clinic varargs bugfixes

Fix out-of-bounds error in _PyArg_UnpackKeywordsWithVararg().

Fix incorrect check which allowed more than one varargs in clinic.py.

Fix miscalculation of noptargs in generated code.

Do not generate noptargs when there is a vararg argument and no optional argument.

C API

gh-98680 [https://github.com/python/cpython/issues/98680]: PyBUF_* constants were marked as part of Limited API of Python 3.11+. These were available in 3.11.0 with Py_LIMITED_API defined for 3.11, and are necessary to use the buffer API.

gh-99612 [https://github.com/python/cpython/issues/99612]: Fix PyUnicode_DecodeUTF8Stateful() for ASCII-only data: *consumed was not set.

gh-47146 [https://github.com/python/cpython/issues/47146]: The structmember.h header is deprecated. Its non-deprecated contents are now available just by including Python.h, with a Py_ prefix added if it was missing. (Deprecated contents are T_OBJECT, T_NONE, and no-op flags.) Patch by Petr Viktorin, based on earlier work by Alexander Belopolsky and Matthias Braun.

Python 3.12.0 alpha 2

Release date: 2022-11-14

Security

gh-98433 [https://github.com/python/cpython/issues/98433]: The IDNA codec decoder used on DNS hostnames by socket or asyncio related name resolution functions no longer involves a quadratic algorithm. This prevents a potential CPU denial of service if an out-of-spec excessive length hostname involving bidirectional characters were decoded. Some protocols such as urllib http 3xx redirects potentially allow for an attacker to supply such a name.

Individual labels within an IDNA encoded DNS name will now raise an error early during IDNA decoding if they are longer than 1024 unicode characters given that each decoded DNS label must be 63 or fewer characters and the entire decoded DNS name is limited to 255. Only an application presenting a hostname or label consisting primarily of RFC 3454 [https://datatracker.ietf.org/doc/html/rfc3454.html] section 3.1 “Nothing” characters to be removed would run into of this new limit. See also RFC 5894 [https://datatracker.ietf.org/doc/html/rfc5894.html] section 6 and RFC 3491 [https://datatracker.ietf.org/doc/html/rfc3491.html].

gh-98739 [https://github.com/python/cpython/issues/98739]: Update bundled libexpat to 2.5.0

Core and Builtins

gh-81057 [https://github.com/python/cpython/issues/81057]: The docs clearly say that PyImport_Inittab, PyImport_AppendInittab(), and PyImport_ExtendInittab() should not be used after Py_Initialize() has been called. We now enforce this for the two functions. Additionally, the runtime now uses an internal copy of PyImport_Inittab, to guard against modification.

gh-99298 [https://github.com/python/cpython/issues/99298]: Fix an issue that could potentially cause incorrect error handling for some bytecode instructions.

gh-99254 [https://github.com/python/cpython/issues/99254]: The compiler now removes all unused constants from code objects (except the first one, which may be a docstring).

gh-99205 [https://github.com/python/cpython/issues/99205]: Fix an issue that prevented PyThreadState and PyInterpreterState memory from being freed properly.

gh-81057 [https://github.com/python/cpython/issues/81057]: The 18 global C variables holding the state of the allocators have been moved to _PyRuntimeState. This is a strictly internal change with no change in behavior.

gh-99181 [https://github.com/python/cpython/issues/99181]: Fix failure in except* with unhashable exceptions.

gh-99204 [https://github.com/python/cpython/issues/99204]: Fix calculation of sys._base_executable when inside a POSIX virtual environment using copies of the python binary when the base installation does not provide the executable name used by the venv. Calculation will fall back to alternative names (“python<MAJOR>”, “python<MAJOR>.<MINOR>”).

gh-96055 [https://github.com/python/cpython/issues/96055]: Update faulthandler to emit an error message with the proper unexpected signal number. Patch by Donghee Na.

gh-99153 [https://github.com/python/cpython/issues/99153]: Fix location of SyntaxError for a try block with both except and except*.

gh-98686 [https://github.com/python/cpython/issues/98686]: Merge the adaptive opcode logic into each instruction’s unquickened variant, and merge the logic in EXTENDED_ARG_QUICK into EXTENDED_ARG. With these changes, the quickening that happens at code object creation is now only responsible for initializing warmup counters and inserting superinstructions.

gh-99103 [https://github.com/python/cpython/issues/99103]: Fix the error reporting positions of specialized traceback anchors when the source line contains Unicode characters.

gh-99139 [https://github.com/python/cpython/issues/99139]: Improve the error suggestion for NameError exceptions for instances. Now if a NameError is raised in a method and the instance has an attribute that’s exactly equal to the name in the exception, the suggestion will include self.<NAME> instead of the closest match in the method scope. Patch by Pablo Galindo

gh-98401 [https://github.com/python/cpython/issues/98401]: Octal escapes with value larger than 0o377 (ex: "\477"), deprecated in Python 3.11, now produce a SyntaxWarning, instead of DeprecationWarning. In a future Python version they will be eventually a SyntaxError. Patch by Victor Stinner.

gh-98401 [https://github.com/python/cpython/issues/98401]: A backslash-character pair that is not a valid escape sequence now generates a SyntaxWarning, instead of DeprecationWarning. For example, re.compile("\d+\.\d+") now emits a SyntaxWarning ("\d" is an invalid escape sequence), use raw strings for regular expression: re.compile(r"\d+\.\d+"). In a future Python version, SyntaxError will eventually be raised, instead of SyntaxWarning. Patch by Victor Stinner.

gh-96793 [https://github.com/python/cpython/issues/96793]: Handle StopIteration and StopAsyncIteration raised in generator or coroutines in the bytecode, rather than in wrapping C code.

gh-98931 [https://github.com/python/cpython/issues/98931]: Improve the SyntaxError error message when the user types import x from y instead of from y import x. Patch by Pablo Galindo

gh-98852 [https://github.com/python/cpython/issues/98852]: Fix subscription of type aliases containing bare generic types or types like TypeVar: for example tuple[A, T][int] and tuple[TypeVar, T][int], where A is a generic type, and T is a type variable.

gh-98925 [https://github.com/python/cpython/issues/98925]: Lower the recursion depth for marshal on WASI to support (in-development) wasmtime 2.0.

gh-98783 [https://github.com/python/cpython/issues/98783]: Fix multiple crashes in debug mode when str subclasses are used instead of str itself.

gh-98811 [https://github.com/python/cpython/issues/98811]: Use complete source locations to simplify detection of __future__ imports which are not at the beginning of the file. Also corrects the offset in the exception raised in one case, which was off by one and impeded highlighting.

gh-96793 [https://github.com/python/cpython/issues/96793]: Add specialization of FOR_ITER for generators. Saves multiple layers of dispatch and checking to get from the FOR_ITER instruction in the caller to the RESUME in the generator.

gh-98762 [https://github.com/python/cpython/issues/98762]: Fix source locations of match sub-patterns.

gh-98586 [https://github.com/python/cpython/issues/98586]: Added the methods PyObject_Vectorcall() and PyObject_VectorcallMethod() to the Limited API along with the auxiliary macro constant PY_VECTORCALL_ARGUMENTS_OFFSET.

The availability of these functions enables more efficient PEP 590 [https://peps.python.org/pep-0590/] vector calls from binary extension modules that avoid argument boxing/unboxing overheads.

gh-99257 [https://github.com/python/cpython/issues/99257]: Fix an issue where member descriptors (such as those for __slots__) could behave incorrectly or crash instead of raising a TypeError when accessed via an instance of an invalid type.

gh-93143 [https://github.com/python/cpython/issues/93143]: Rather than changing co_code, the interpreter will now display a RuntimeWarning and assign None to any fast locals that are left unbound after jumps or del statements executed while tracing.

gh-96421 [https://github.com/python/cpython/issues/96421]: When calling into Python code from C code, through PyEval_EvalFrameEx() or a related C-API function, a shim frame in inserted into the call stack. This occurs in the _PyEval_EvalFrameDefault() function. The extra frame should be invisible to all Python and most C extensions, but out-of-process profilers and debuggers need to be aware of it. These shim frames can be detected by checking frame->owner == FRAME_OWNED_BY_CSTACK.

Extensions implementing their own interpreters using PEP 523 need to be aware of this shim frame and the changes to the semantics of RETURN_VALUE, YIELD_VALUE, and RETURN_GENERATOR, which now clear the frame.

gh-98415 [https://github.com/python/cpython/issues/98415]: Fix detection of MAC addresses for uuid on certain OSs. Patch by Chaim Sanders

gh-98686 [https://github.com/python/cpython/issues/98686]: Quicken all code objects, and specialize adaptive bytecode instructions more aggressively.

gh-92119 [https://github.com/python/cpython/issues/92119]: Print exception class name instead of its string representation when raising errors from ctypes calls.

gh-91058 [https://github.com/python/cpython/issues/91058]: ImportError raised from failed from <module> import <name> now include suggestions for the value of <name> based on the available names in <module>. Patch by Pablo Galindo

gh-96793 [https://github.com/python/cpython/issues/96793]: The FOR_ITER now leaves the iterator on the stack on termination of the loop. This is to assist specialization of loops for generators.

gh-90716 [https://github.com/python/cpython/issues/90716]: Add _pylong.py module. It includes asymptotically faster algorithms that can be used for operations on integers with many digits. It is used by longobject.c to speed up some operations.

gh-95389 [https://github.com/python/cpython/issues/95389]: Expose ETH_P_ALL and some of the ETHERTYPE_* constants in socket. Patch by Noam Cohen.

gh-93696 [https://github.com/python/cpython/issues/93696]: Allow pdb to locate source for frozen modules in the standard library.

Library

gh-99418 [https://github.com/python/cpython/issues/99418]: Fix bug in urllib.parse.urlparse() that causes URL schemes that begin with a digit, a plus sign, or a minus sign to be parsed incorrectly.

gh-94597 [https://github.com/python/cpython/issues/94597]: Deprecate asyncio.AbstractChildWatcher to be removed in Python 3.14. Patch by Kumar Aditya.

gh-99305 [https://github.com/python/cpython/issues/99305]: Improve performance of secrets.token_hex().

gh-74044 [https://github.com/python/cpython/issues/74044]: Fixed bug where inspect.signature() reported incorrect arguments for decorated methods.

gh-99275 [https://github.com/python/cpython/issues/99275]: Fix SystemError in ctypes when exception was not set during __initsubclass__.

gh-99277 [https://github.com/python/cpython/issues/99277]: Remove older version of _SSLProtocolTransport.get_write_buffer_limits in asyncio.sslproto

gh-99248 [https://github.com/python/cpython/issues/99248]: fix negative numbers failing in verify()

gh-99155 [https://github.com/python/cpython/issues/99155]: Fix statistics.NormalDist pickle with 0 and 1 protocols.

gh-93464 [https://github.com/python/cpython/issues/93464]: enum.auto() is now correctly activated when combined with other assignment values. E.g. ONE = auto(), 'some text' will now evaluate as (1, 'some text').

gh-99134 [https://github.com/python/cpython/issues/99134]: Update the bundled copy of pip to version 22.3.1.

gh-92584 [https://github.com/python/cpython/issues/92584]: Remove the distutils package. It was deprecated in Python 3.10 by PEP 632 [https://peps.python.org/pep-0632/] “Deprecate distutils module”. For projects still using distutils and cannot be updated to something else, the setuptools project can be installed: it still provides distutils. Patch by Victor Stinner.

gh-98999 [https://github.com/python/cpython/issues/98999]: Now _pyio is consistent with _io in raising ValueError when executing methods over closed buffers.

gh-83004 [https://github.com/python/cpython/issues/83004]: Clean up refleak on failed module initialisation in _zoneinfo

gh-83004 [https://github.com/python/cpython/issues/83004]: Clean up refleaks on failed module initialisation in _pickle

gh-83004 [https://github.com/python/cpython/issues/83004]: Clean up refleak on failed module initialisation in _io.

gh-98897 [https://github.com/python/cpython/issues/98897]: Fix memory leak in math.dist() when both points don’t have the same dimension. Patch by Kumar Aditya.

gh-98878 [https://github.com/python/cpython/issues/98878]: Use the frame bound builtins when offering a name suggestion in traceback to prevent crashing when __builtins__ is not a dict.

gh-98139 [https://github.com/python/cpython/issues/98139]: In importlib._bootstrap, enhance namespace package repr to <module 'x' (namespace) from ['path']>.

gh-90352 [https://github.com/python/cpython/issues/90352]: Fix _SelectorDatagramTransport to inherit from DatagramTransport in asyncio. Patch by Kumar Aditya.

gh-98793 [https://github.com/python/cpython/issues/98793]: Fix argument typechecks in _overlapped.WSAConnect() and _overlapped.Overlapped.WSASendTo() functions.

gh-98744 [https://github.com/python/cpython/issues/98744]: Prevent crashing in traceback when retrieving the byte-offset for some source files that contain certain unicode characters.

gh-98740 [https://github.com/python/cpython/issues/98740]: Fix internal error in the re module which in very rare circumstances prevented compilation of a regular expression containing a conditional expression without the “else” branch.

gh-98703 [https://github.com/python/cpython/issues/98703]: Fix asyncio.StreamWriter.drain() to call protocol.connection_lost callback only once on Windows.

gh-98624 [https://github.com/python/cpython/issues/98624]: Add a mutex to unittest.mock.NonCallableMock to protect concurrent access to mock attributes.

gh-98658 [https://github.com/python/cpython/issues/98658]: The array.array class now supports subscripting, making it a generic type.

gh-98284 [https://github.com/python/cpython/issues/98284]: Improved TypeError message for undefined abstract methods of a abc.ABC instance. The names of the missing methods are surrounded by single-quotes to highlight them.

gh-96151 [https://github.com/python/cpython/issues/96151]: Allow BUILTINS to be a valid field name for frozen dataclasses.

gh-98086 [https://github.com/python/cpython/issues/98086]: Make sure patch.dict() can be applied on async functions.

gh-72719 [https://github.com/python/cpython/issues/72719]: Remove modules asyncore and asynchat, which were deprecated by PEP 594 [https://peps.python.org/pep-0594/].

gh-96192 [https://github.com/python/cpython/issues/96192]: Fix handling of bytes path-like objects in os.ismount().

gh-94172 [https://github.com/python/cpython/issues/94172]: ftplib: Remove the FTP_TLS.ssl_version class attribute: use the context parameter instead. Patch by Victor Stinner

gh-94172 [https://github.com/python/cpython/issues/94172]: Remove the keyfile and certfile parameters from the ftplib, imaplib, poplib and smtplib modules, and the key_file, cert_file and check_hostname parameters from the http.client module, all deprecated since Python 3.6. Use the context parameter (ssl_context in imaplib) instead. Patch by Victor Stinner.

gh-83638 [https://github.com/python/cpython/issues/83638]: Add the autocommit attribute to sqlite3.Connection and the autocommit parameter to sqlite3.connect() to control PEP 249 [https://peps.python.org/pep-0249/]-compliant transaction handling. Patch by Erlend E. Aasland.

gh-92452 [https://github.com/python/cpython/issues/92452]: Fixed a race condition that could cause sysconfig.get_config_var() to incorrectly return None in multi-threaded programs.

gh-91803 [https://github.com/python/cpython/issues/91803]: Fix an error when using a method of objects mocked with unittest.mock.create_autospec() after it was sealed with unittest.mock.seal() function.

bpo-38523 [https://bugs.python.org/issue?@action=redirect&bpo=38523]: shutil.copytree() now applies the ignore_dangling_symlinks argument recursively.

bpo-40358 [https://bugs.python.org/issue?@action=redirect&bpo=40358]: Add walk_up argument in pathlib.PurePath.relative_to().

bpo-36267 [https://bugs.python.org/issue?@action=redirect&bpo=36267]: Fix IndexError in argparse.ArgumentParser when a store_true action is given an explicit argument.

Documentation

gh-98832 [https://github.com/python/cpython/issues/98832]: Changes wording of docstring for pathlib.Path.iterdir().

gh-97966 [https://github.com/python/cpython/issues/97966]: Update uname docs to clarify the special nature of the platform attribute and to indicate when it became late-bound.

Tests

gh-98903 [https://github.com/python/cpython/issues/98903]: The Python test suite now fails with exit code 4 if no tests ran. It should help detecting typos in test names and test methods.

gh-98713 [https://github.com/python/cpython/issues/98713]: Fix a bug in the typing tests where a test relying on CPython-specific implementation details was not decorated with @cpython_only and was not skipped on other implementations.

gh-87390 [https://github.com/python/cpython/issues/87390]: Add tests for star-unpacking with PEP 646, and some other miscellaneous PEP 646 tests.

gh-96853 [https://github.com/python/cpython/issues/96853]: Added explicit coverage of Py_Initialize (and hence Py_InitializeEx) back to the embedding tests (all other embedding tests migrated to Py_InitializeFromConfig in Python 3.11)

bpo-34272 [https://bugs.python.org/issue?@action=redirect&bpo=34272]: Some C API tests were moved into the new Lib/test/test_capi/ directory.

Build

gh-99086 [https://github.com/python/cpython/issues/99086]: Fix -Wimplicit-int compiler warning in configure check for PTHREAD_SCOPE_SYSTEM.

gh-99016 [https://github.com/python/cpython/issues/99016]: Fix build with PYTHON_FOR_REGEN=python3.8.

gh-97731 [https://github.com/python/cpython/issues/97731]: Specify the full path to the source location for make docclean (needed for cross-builds).

gh-98949 [https://github.com/python/cpython/issues/98949]: Drop unused build dependency on readelf.

gh-98989 [https://github.com/python/cpython/issues/98989]: Use python3.11, if available, for regeneration and freezing.

gh-98831 [https://github.com/python/cpython/issues/98831]: Add new tooling, in Tools/cases_generator, to generate the interpreter switch statement from a list of opcode definitions. This only affects adding, modifying or removing instruction definitions. The instruction definitions now live in Python/bytecodes.c, in the form of a custom DSL (under development) [https://github.com/faster-cpython/ideas/blob/main/3.12/interpreter_definition.md]. The tooling reads this file and writes Python/generated_cases.c.h, which is then included by Python/ceval.c to provide most of the cases of the main interpreter switch.

gh-98817 [https://github.com/python/cpython/issues/98817]: Remove PCbuild/lib.pyproj: it’s not used for anything, is only a minor convenience for Visual Studio users (who probably mostly don’t even know about it), and it takes a lot of maintenance effort to keep updated.

gh-98776 [https://github.com/python/cpython/issues/98776]: Fix make regen-test-levenshtein for out-of-tree builds.

gh-98707 [https://github.com/python/cpython/issues/98707]: Don’t use vendored libmpdec headers if --with-system-libmpdec is passed to configure. Don’t use vendored libexpat headers if --with-system-expat is passed to configure.

Windows

gh-98689 [https://github.com/python/cpython/issues/98689]: Update Windows builds to zlib v1.2.13. v1.2.12 has CVE 2022-37434 [https://www.cve.org/CVERecord?id=CVE-2022-37434], but the vulnerable inflateGetHeader API is not used by Python.

gh-98790 [https://github.com/python/cpython/issues/98790]: Assumes that a missing DLLs directory means that standard extension modules are in the executable’s directory.

gh-98745 [https://github.com/python/cpython/issues/98745]: Update py.exe launcher to install 3.11 by default and 3.12 on request.

gh-98692 [https://github.com/python/cpython/issues/98692]: Fix the 윈도우 용 파이썬 런처 ignoring unrecognized shebang lines instead of treating them as local paths

gh-94328 [https://github.com/python/cpython/issues/94328]: Update Windows installer to use SQLite 3.39.4.

macOS

gh-94328 [https://github.com/python/cpython/issues/94328]: Update macOS installer to SQLite 3.39.4.

C API

gh-98724 [https://github.com/python/cpython/issues/98724]: The Py_CLEAR, Py_SETREF and Py_XSETREF macros now only evaluate their argument once. If the argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.

gh-98978 [https://github.com/python/cpython/issues/98978]: Fix use-after-free in Py_SetPythonHome(NULL), Py_SetProgramName(NULL) and _Py_SetProgramFullPath(NULL) function calls. Issue reported by Benedikt Reinartz. Patch by Victor Stinner.

gh-98410 [https://github.com/python/cpython/issues/98410]: Add getbufferproc and releasebufferproc to the stable API.

gh-98610 [https://github.com/python/cpython/issues/98610]: Some configurable capabilities of sub-interpreters have changed. They always allow subprocesses (subprocess) now, whereas before subprocesses could be optionally disallowed for a sub-interpreter. Instead os.exec() can now be disallowed. Disallowing daemon threads is now supported. Disallowing all threads is still allowed, but is never done by default. Note that the optional restrictions are only available through _Py_NewInterpreterFromConfig(), which isn’t a public API. They do not affect the main interpreter, nor Py_NewInterpreter().

gh-98608 [https://github.com/python/cpython/issues/98608]: A _PyInterpreterConfig has been added and _Py_NewInterpreter() has been renamed to _Py_NewInterpreterFromConfig(). The “isolated_subinterpreters” argument is now a granular config that captures the previous behavior. Note that this is all “private” API.

gh-96853 [https://github.com/python/cpython/issues/96853]: Py_InitializeEx now correctly calls PyConfig_Clear after initializing the interpreter (the omission didn’t cause a memory leak only because none of the dynamically allocated config fields are populated by the wrapper function)

gh-91248 [https://github.com/python/cpython/issues/91248]: Add PyFrame_GetVar() and PyFrame_GetVarString() functions to get a frame variable by its name. Patch by Victor Stinner.

Python 3.12.0 alpha 1

Release date: 2022-10-25

Security

gh-97616 [https://github.com/python/cpython/issues/97616]: Fix multiplying a list by an integer (list *= int): detect the integer overflow when the new allocated length is close to the maximum size. Issue reported by Jordan Limor. Patch by Victor Stinner.

gh-97514 [https://github.com/python/cpython/issues/97514]: On Linux the multiprocessing module returns to using filesystem backed unix domain sockets for communication with the forkserver process instead of the Linux abstract socket namespace. Only code that chooses to use the “forkserver” start method is affected.

Abstract sockets have no permissions and could allow any user on the system in the same network namespace [https://man7.org/linux/man-pages/man7/network_namespaces.7.html] (often the whole system) to inject code into the multiprocessing forkserver process. This was a potential privilege escalation. Filesystem based socket permissions restrict this to the forkserver process user as was the default in Python 3.8 and earlier.

This prevents Linux CVE 2022-42919 [https://www.cve.org/CVERecord?id=CVE-2022-42919].

gh-87389 [https://github.com/python/cpython/issues/87389]: http.server: Fix an open redirection vulnerability in the HTTP server when an URI path starts with //. Vulnerability discovered, and initial fix proposed, by Hamza Avvan.

gh-79096 [https://github.com/python/cpython/issues/79096]: LWPCookieJar and MozillaCookieJar create files with file mode 600 instead of 644 (Microsoft Windows is not affected)

gh-92888 [https://github.com/python/cpython/issues/92888]: Fix memoryview use after free when accessing the backing buffer in certain cases.

gh-68966 [https://github.com/python/cpython/issues/68966]: The deprecated mailcap module now refuses to inject unsafe text (filenames, MIME types, parameters) into shell commands. Instead of using such text, it will warn and act as if a match was not found (or for test commands, as if the test failed).

Core and Builtins

gh-98374 [https://github.com/python/cpython/issues/98374]: Suppress ImportError for invalid query for help() command. Patch by Donghee Na.

gh-98461 [https://github.com/python/cpython/issues/98461]: Fix source location in bytecode for list, set and dict comprehensions as well as generator expressions.

gh-98354 [https://github.com/python/cpython/issues/98354]: Added unicode check for name attribute of spec argument passed in _imp.create_builtin() function.

gh-98398 [https://github.com/python/cpython/issues/98398]: Fix source location of ‘assert’ bytecodes.

gh-98390 [https://github.com/python/cpython/issues/98390]: Fix location of sub-expressions of boolean expressions, by reducing their scope to that of the sub-expression.

gh-98254 [https://github.com/python/cpython/issues/98254]: Modules from the standard library are now potentially suggested as part of the error messages displayed by the interpreter when an NameError is raised to the top level. Patch by Pablo Galindo

gh-97997 [https://github.com/python/cpython/issues/97997]: Add running column offset to the tokenizer state to avoid calculating AST column information with pointer arithmetic.

gh-97973 [https://github.com/python/cpython/issues/97973]: Modify the tokenizer to return all necessary information the parser needs to set location information in the AST nodes, so that the parser does not have to calculate those doing pointer arithmetic.

gh-96078 [https://github.com/python/cpython/issues/96078]: os.sched_yield() now release the GIL while calling sched_yield(2). Patch by Donghee Na.

gh-97955 [https://github.com/python/cpython/issues/97955]: Migrate zoneinfo to Argument Clinic.

gh-97912 [https://github.com/python/cpython/issues/97912]: The compiler now avoids quadratic behavior when finding which instructions should use the LOAD_FAST_CHECK opcode.

gh-97002 [https://github.com/python/cpython/issues/97002]: Fix an issue where several frame objects could be backed by the same interpreter frame, possibly leading to corrupted memory and hard crashes of the interpreter.

gh-97943 [https://github.com/python/cpython/issues/97943]: Bugfix: PyFunction_GetAnnotations() should return a borrowed reference. It was returning a new reference.

gh-97922 [https://github.com/python/cpython/issues/97922]: The Garbage Collector now runs only on the eval breaker mechanism of the Python bytecode evaluation loop instead on object allocations. The GC can also run when PyErr_CheckSignals() is called so C extensions that need to run for a long time without executing any Python code also have a chance to execute the GC periodically.

gh-65961 [https://github.com/python/cpython/issues/65961]: When __package__ is different than __spec__.parent, raise a DeprecationWarning instead of ImportWarning.

Also remove importlib.util.set_package() which was scheduled for removal.

gh-97850 [https://github.com/python/cpython/issues/97850]: Long deprecated, module_repr() should now be completely eradicated.

gh-86298 [https://github.com/python/cpython/issues/86298]: In cases where warnings.warn_explicit() consults the module’s loader, an DeprecationWarning is issued when m.__loader__ differs from m.__spec__.loader.

gh-97779 [https://github.com/python/cpython/issues/97779]: Ensure that all Python frame objects are backed by “complete” frames.

gh-91052 [https://github.com/python/cpython/issues/91052]: Add API for subscribing to modification events on selected dictionaries.

gh-97752 [https://github.com/python/cpython/issues/97752]: Fix possible data corruption or crashes when accessing the f_back member of newly-created generator or coroutine frames.

gh-97591 [https://github.com/python/cpython/issues/97591]: Fixed a missing incref/decref pair in Exception.__setstate__(). Patch by Ofey Chan.

gh-97670 [https://github.com/python/cpython/issues/97670]: Remove the sys.getdxp() function and the Tools/scripts/analyze_dxp.py script. DXP stands for “dynamic execution pairs”. They were related to DYNAMIC_EXECUTION_PROFILE and DXPAIRS macros which have been removed in Python 3.11. Python can now be built with ./configure --enable-pystats to gather statistics on Python opcodes. Patch by Victor Stinner.

gh-94526 [https://github.com/python/cpython/issues/94526]: Fix the Python path configuration used to initialized sys.path at Python startup. Paths are no longer encoded to UTF-8/strict to avoid encoding errors if it contains surrogate characters (bytes paths are decoded with the surrogateescape error handler). Patch by Victor Stinner.

gh-96670 [https://github.com/python/cpython/issues/96670]: The parser now raises SyntaxError when parsing source code containing null bytes. Patch by Pablo Galindo

gh-96975 [https://github.com/python/cpython/issues/96975]: Fix a crash occurring when PyEval_GetFrame() is called while the topmost Python frame is in a partially-initialized state.

gh-96848 [https://github.com/python/cpython/issues/96848]: Fix command line parsing: reject -X int_max_str_digits option with no value (invalid) when the PYTHONINTMAXSTRDIGITS environment variable is set to a valid limit. Patch by Victor Stinner.

gh-95921 [https://github.com/python/cpython/issues/95921]: Fix overly-broad source position information for chained comparisons used as branching conditions.

gh-96821 [https://github.com/python/cpython/issues/96821]: Fix undefined behaviour in audioop.c.

gh-96821 [https://github.com/python/cpython/issues/96821]: Fix undefined behaviour in _testcapimodule.c.

gh-95778 [https://github.com/python/cpython/issues/95778]: When ValueError is raised if an integer is larger than the limit, mention the sys.set_int_max_str_digits() function in the error message. Patch by Victor Stinner.

gh-96387 [https://github.com/python/cpython/issues/96387]: At Python exit, sometimes a thread holding the GIL can wait forever for a thread (usually a daemon thread) which requested to drop the GIL, whereas the thread already exited. To fix the race condition, the thread which requested the GIL drop now resets its request before exiting. Issue discovered and analyzed by Mingliang ZHAO. Patch by Victor Stinner.

gh-96864 [https://github.com/python/cpython/issues/96864]: Fix a possible assertion failure, fatal error, or SystemError if a line tracing event raises an exception while opcode tracing is enabled.

gh-95778 [https://github.com/python/cpython/issues/95778]: The PyLong_FromString function was refactored to make it more maintainable and extensible.

gh-96678 [https://github.com/python/cpython/issues/96678]: Fix undefined behaviour in C code of null pointer arithmetic.

gh-96754 [https://github.com/python/cpython/issues/96754]: Make sure that all frame objects created are created from valid interpreter frames. Prevents the possibility of invalid frames in backtraces and signal handlers.

gh-90997 [https://github.com/python/cpython/issues/90997]: Improve the performance of reading and writing inline bytecode caches on some platforms.

gh-96751 [https://github.com/python/cpython/issues/96751]: Remove dead code from CALL_FUNCTION_EX opcode.

gh-90751 [https://github.com/python/cpython/issues/90751]: memoryview now supports half-floats. Patch by Donghee Na and Antoine Pitrou.

gh-96678 [https://github.com/python/cpython/issues/96678]: Fix case of undefined behavior in ceval.c

gh-64373 [https://github.com/python/cpython/issues/64373]: Convert _functools to argument clinic.

gh-96641 [https://github.com/python/cpython/issues/96641]: Do not expose KeyWrapper in _functools.

gh-96636 [https://github.com/python/cpython/issues/96636]: Ensure that tracing, sys.setrace(), is turned on immediately. In pre-release versions of 3.11, some tracing events might have been lost when turning on tracing in a __del__ method or interrupt.

gh-96572 [https://github.com/python/cpython/issues/96572]: Fix use after free in trace refs build mode. Patch by Kumar Aditya.

gh-96611 [https://github.com/python/cpython/issues/96611]: When loading a file with invalid UTF-8 inside a multi-line string, a correct SyntaxError is emitted.

gh-96612 [https://github.com/python/cpython/issues/96612]: Make sure that incomplete frames do not show up in tracemalloc traces.

gh-90230 [https://github.com/python/cpython/issues/90230]: Fix compiler warnings and test failures when building with --enable-pystats.

gh-96587 [https://github.com/python/cpython/issues/96587]: Correctly raise SyntaxError on exception groups (PEP 654 [https://peps.python.org/pep-0654/]) on python versions prior to 3.11

gh-96569 [https://github.com/python/cpython/issues/96569]: Remove two cases of undefined behavior, by adding NULL checks.

gh-96582 [https://github.com/python/cpython/issues/96582]: Fix possible NULL pointer dereference in _PyThread_CurrentFrames. Patch by Kumar Aditya.

gh-91079 [https://github.com/python/cpython/issues/91079]: Separate Python recursion checking from C recursion checking which reduces the chance of C stack overflow and allows the recursion limit to be increased safely.

gh-93911 [https://github.com/python/cpython/issues/93911]: Fix an issue that could prevent LOAD_ATTR from specializing properly when accessing properties.

gh-96348 [https://github.com/python/cpython/issues/96348]: Emit a DeprecationWarning when throw(), throw() or athrow() are called with more than one argument.

gh-95196 [https://github.com/python/cpython/issues/95196]: Disable incorrect pickling of the C implemented classmethod descriptors.

gh-96364 [https://github.com/python/cpython/issues/96364]: Fix text signatures of list.__getitem__ and dict.__getitem__.

gh-96352 [https://github.com/python/cpython/issues/96352]: Fix AttributeError missing name and obj attributes in object.__getattribute__(). Patch by Philip Georgi.

gh-93554 [https://github.com/python/cpython/issues/93554]: Change the jump opcodes so that all conditional jumps are forward jumps. Backward jumps are converted by the assembler into a conditional forward jump whose target is the fallthrough block (and with a reversed condition), followed by an unconditional backward jump. For example:

POP_JUMP_IF_TRUE BACKWARD_TARGET becomes POP_JUMP_IF_FALSE NEXT_BLOCK; JUMP BACKWARD_TARGET.

All the directed conditional jump opcodes were removed: POP_JUMP_FORWARD_IF_TRUE, POP_JUMP_BACKWARD_IF_TRUE, POP_JUMP_FORWARD_IF_FALSE, POP_JUMP_BACKWARD_IF_FALSE, POP_JUMP_FORWARD_IF_NONE, POP_JUMP_BACKWARD_IF_NONE, POP_JUMP_FORWARD_IF_NOT_NONE, POP_JUMP_BACKWARD_IF_NOT_NONE.

The corresponding opcodes without direction are no longer pseudo-instructions, and they implement the forward conditional jumps.

gh-96268 [https://github.com/python/cpython/issues/96268]: Loading a file with invalid UTF-8 will now report the broken character at the correct location.

gh-96237 [https://github.com/python/cpython/issues/96237]: The internal field _PyInterpreterFrame.f_func is renamed to _PyInterpreterFrame.f_funcobj and may be any object. The f_globals and f_builtin fields may hold junk values.

It is safest to treat the _PyInterpreterFrame struct as opaque.

gh-96187 [https://github.com/python/cpython/issues/96187]: Fixed a bug that caused _PyCode_GetExtra to return garbage for negative indexes. Patch by Pablo Galindo

gh-96143 [https://github.com/python/cpython/issues/96143]: Add a new -X perf Python command line option as well as sys.activate_stack_trampoline() and sys.deactivate_stack_trampoline() function in the sys module that allows to set/unset the interpreter in a way that the Linux perf profiler can detect Python calls. The new sys.is_stack_trampoline_active() function allows to query the state of the perf trampoline. Design by Pablo Galindo. Patch by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith [Google] and Mark Shannon.

gh-96071 [https://github.com/python/cpython/issues/96071]: Fix a deadlock in PyGILState_Ensure() when allocating new thread state. Patch by Kumar Aditya.

gh-96046 [https://github.com/python/cpython/issues/96046]: PyType_Ready() now initializes ht_cached_keys and performs additional checks to ensure that type objects are properly configured. This avoids crashes in 3rd party packages that don’t use regular API to create new types.

gh-96005 [https://github.com/python/cpython/issues/96005]: On WASI ENOTCAPABLE is now mapped to PermissionError. The errno modules exposes the new error number. getpath.py now ignores PermissionError when it cannot open landmark files pybuilddir.txt and pyenv.cfg.

gh-93678 [https://github.com/python/cpython/issues/93678]: Added test a harness for direct unit tests of the compiler’s optimization stage. The _testinternalcapi.optimize_cfg() function runs the optimiser on a sequence of instructions. The CfgOptimizationTestCase class in test.support has utilities for invoking the optimizer and checking the output.

gh-95245 [https://github.com/python/cpython/issues/95245]: Reduces the size of a “simple” Python object from 8 to 6 words by moving the weakreflist pointer into the pre-header directly before the object’s dict/values pointer.

gh-90997 [https://github.com/python/cpython/issues/90997]: Compile virtual try/except blocks to handle exceptions raised during close() or throw() calls through a suspended frame.

gh-95977 [https://github.com/python/cpython/issues/95977]: Optimized calling __get__() with vectorcall. Patch by Kumar Aditya.

gh-91210 [https://github.com/python/cpython/issues/91210]: Improve error message when a parameter without a default value follows one with a default value, and show the same message, even when the non-default/default sequence is preceded by positional-only parameters.

gh-95922 [https://github.com/python/cpython/issues/95922]: Fixed bug where the compiler’s eliminate_empty_basic_blocks function ignores the last block of the code unit.

gh-95818 [https://github.com/python/cpython/issues/95818]: Skip over incomplete frames in PyThreadState_GetFrame().

gh-95876 [https://github.com/python/cpython/issues/95876]: Fix format string in _PyPegen_raise_error_known_location that can lead to memory corruption on some 64bit systems. The function was building a tuple with i (int) instead of n (Py_ssize_t) for Py_ssize_t arguments.

gh-95605 [https://github.com/python/cpython/issues/95605]: Fix misleading contents of error message when converting an all-whitespace string to float.

gh-95150 [https://github.com/python/cpython/issues/95150]: Update code object hashing and equality to consider all debugging and exception handling tables. This fixes an issue where certain non-identical code objects could be “deduplicated” during compilation.

gh-91146 [https://github.com/python/cpython/issues/91146]: Reduce allocation size of list from str.split() and str.rsplit(). Patch by Donghee Na and Inada Naoki.

gh-87092 [https://github.com/python/cpython/issues/87092]: Create a ‘jump target label’ abstraction in the compiler so that the compiler’s codegen stage does not work directly with basic blocks. This prepares the code for changes to the underlying CFG generation mechanism.

gh-95355 [https://github.com/python/cpython/issues/95355]: _PyPegen_Parser_New now properly detects token memory allocation errors. Patch by Honglin Zhu.

gh-90081 [https://github.com/python/cpython/issues/90081]: Run Python code in tracer/profiler function at full speed. Fixes slowdown in earlier versions of 3.11.

gh-95324 [https://github.com/python/cpython/issues/95324]: Emit a warning in debug mode if an object does not call PyObject_GC_UnTrack() before deallocation. Patch by Pablo Galindo.

gh-95245 [https://github.com/python/cpython/issues/95245]: Merge managed dict and values pointer into a single tagged pointer to save one word in the pre-header.

gh-93678 [https://github.com/python/cpython/issues/93678]: Add cfg_builder struct and refactor the relevant code so that a cfg can be constructed without an instance of the compiler struct.

gh-95185 [https://github.com/python/cpython/issues/95185]: Prevented crashes in the AST constructor when compiling some absurdly long expressions like "+0"*1000000. RecursionError is now raised instead. Patch by Pablo Galindo

gh-93351 [https://github.com/python/cpython/issues/93351]: ast.AST node positions are now validated when provided to compile() and other related functions. If invalid positions are detected, a ValueError will be raised.

gh-94438 [https://github.com/python/cpython/issues/94438]: Fix an issue that caused extended opcode arguments and some conditional pops to be ignored when calculating valid jump targets for assignments to the f_lineno attribute of frame objects. In some cases, this could cause inconsistent internal state, resulting in a hard crash of the interpreter.

gh-95060 [https://github.com/python/cpython/issues/95060]: Undocumented PyCode_Addr2Location function now properly returns when addrq argument is less than zero.

gh-95113 [https://github.com/python/cpython/issues/95113]: Replace all EXTENDED_ARG_QUICK instructions with basic EXTENDED_ARG instructions in unquickened code. Consumers of non-adaptive bytecode should be able to handle extended arguments the same way they were handled in CPython 3.10 and older.

gh-91409 [https://github.com/python/cpython/issues/91409]: Fix incorrect source location info caused by certain optimizations in the bytecode compiler.

gh-95023 [https://github.com/python/cpython/issues/95023]: Implement os.setns() and os.unshare() for Linux. Patch by Noam Cohen.

gh-94036 [https://github.com/python/cpython/issues/94036]: Fix incorrect source location info for some multi-line attribute accesses and method calls.

gh-94938 [https://github.com/python/cpython/issues/94938]: Fix error detection in some builtin functions when keyword argument name is an instance of a str subclass with overloaded __eq__ and __hash__. Previously it could cause SystemError or other undesired behavior.

gh-94996 [https://github.com/python/cpython/issues/94996]: ast.parse() will no longer parse function definitions with positional-only params when passed feature_version less than (3, 8). Patch by Shantanu Jain.

gh-94739 [https://github.com/python/cpython/issues/94739]: Allow jumping within, out of, and across exception handlers in the debugger.

gh-94949 [https://github.com/python/cpython/issues/94949]: ast.parse() will no longer parse parenthesized context managers when passed feature_version less than (3, 9). Patch by Shantanu Jain.

gh-94947 [https://github.com/python/cpython/issues/94947]: ast.parse() will no longer parse assignment expressions when passed feature_version less than (3, 8). Patch by Shantanu Jain.

gh-91256 [https://github.com/python/cpython/issues/91256]: Ensures the program name is known for help text during interpreter startup.

gh-94869 [https://github.com/python/cpython/issues/94869]: Fix the column offsets for some expressions in multi-line f-strings ast nodes. Patch by Pablo Galindo.

gh-94893 [https://github.com/python/cpython/issues/94893]: Fix an issue where frame object manipulations could corrupt inline bytecode caches.

gh-94822 [https://github.com/python/cpython/issues/94822]: Fix an issue where lookups of metaclass descriptors may be ignored when an identically-named attribute also exists on the class itself.

gh-91153 [https://github.com/python/cpython/issues/91153]: Fix an issue where a bytearray item assignment could crash if it’s resized by the new value’s __index__() method.

gh-90699 [https://github.com/python/cpython/issues/90699]: Fix reference counting bug in bool.__repr__(). Patch by Kumar Aditya.

gh-94694 [https://github.com/python/cpython/issues/94694]: Fix an issue that could cause code with multi-line method lookups to have misleading or incorrect column offset information. In some cases (when compiling a hand-built AST) this could have resulted in a hard crash of the interpreter.

gh-93252 [https://github.com/python/cpython/issues/93252]: Fix an issue that caused internal frames to outlive failed Python function calls, possibly resulting in memory leaks or hard interpreter crashes.

gh-94215 [https://github.com/python/cpython/issues/94215]: Fix an issue where exceptions raised by line-tracing events would cause frames to be left in an invalid state, possibly resulting in a hard crash of the interpreter.

gh-92228 [https://github.com/python/cpython/issues/92228]: Disable the compiler’s inline-small-exit-blocks optimization for exit blocks that are associated with source code lines. This fixes a bug where the debugger cannot tell where an exception handler ends and the following code block begins.

gh-94485 [https://github.com/python/cpython/issues/94485]: Line number of a module’s RESUME instruction is set to 0 as specified in PEP 626 [https://peps.python.org/pep-0626/].

gh-94438 [https://github.com/python/cpython/issues/94438]: Account for instructions that can push NULL to the stack when setting line number in a frame. Prevents some (unlikely) crashes.

gh-91719 [https://github.com/python/cpython/issues/91719]: Reload opcode when raising unknown opcode error in the interpreter main loop, for C compilers to generate dispatching code independently.

gh-94329 [https://github.com/python/cpython/issues/94329]: Compile and run code with unpacking of extremely large sequences (1000s of elements). Such code failed to compile. It now compiles and runs correctly.

gh-94360 [https://github.com/python/cpython/issues/94360]: Fixed a tokenizer crash when reading encoded files with syntax errors from stdin with non utf-8 encoded text. Patch by Pablo Galindo

gh-88116 [https://github.com/python/cpython/issues/88116]: Fix an issue when reading line numbers from code objects if the encoded line numbers are close to INT_MIN. Patch by Pablo Galindo

gh-94262 [https://github.com/python/cpython/issues/94262]: Don’t create frame objects for incomplete frames. Prevents the creation of generators and closures from being observable to Python and C extensions, restoring the behavior of 3.10 and earlier.

gh-94192 [https://github.com/python/cpython/issues/94192]: Fix error for dictionary literals with invalid expression as value.

gh-87995 [https://github.com/python/cpython/issues/87995]: types.MappingProxyType instances are now hashable if the underlying mapping is hashable.

gh-93883 [https://github.com/python/cpython/issues/93883]: Revise the display strategy of traceback enhanced error locations. The indicators are only shown when the location doesn’t span the whole line.

gh-94163 [https://github.com/python/cpython/issues/94163]: Add BINARY_SLICE and STORE_SLICE instructions for more efficient handling and better specialization of slicing operations, where the slice is explicit in the source code.

gh-94021 [https://github.com/python/cpython/issues/94021]: Fix unreachable code warning in Python/specialize.c.

gh-93911 [https://github.com/python/cpython/issues/93911]: Specialize LOAD_ATTR for objects with custom __getattribute__.

gh-93955 [https://github.com/python/cpython/issues/93955]: Improve performance of attribute lookups on objects with custom __getattribute__ and __getattr__. Patch by Ken Jin.

gh-93911 [https://github.com/python/cpython/issues/93911]: Specialize LOAD_ATTR for property() attributes.

gh-93678 [https://github.com/python/cpython/issues/93678]: Refactor compiler optimisation code so that it no longer needs the struct assembler and struct compiler passed around. Instead, each function takes the CFG and other data that it actually needs. This will make it possible to test this code directly.

gh-93841 [https://github.com/python/cpython/issues/93841]: When built with -enable-pystats, sys._stats_on(), sys._stats_off(), sys._stats_clear() and sys._stats_dump() functions have been added to enable gathering stats for parts of programs.

gh-93516 [https://github.com/python/cpython/issues/93516]: Store offset of first traceable instruction in code object to avoid having to recompute it for each instruction when tracing.

gh-93516 [https://github.com/python/cpython/issues/93516]: Lazily create a table mapping bytecode offsets to line numbers to speed up calculation of line numbers when tracing.

gh-89828 [https://github.com/python/cpython/issues/89828]: types.GenericAlias no longer relays the __class__ attribute. For example, isinstance(list[int], type) no longer returns True.

gh-93678 [https://github.com/python/cpython/issues/93678]: Refactor the compiler to reduce boilerplate and repetition.

gh-93671 [https://github.com/python/cpython/issues/93671]: Fix some exponential backtrace case happening with deeply nested sequence patterns in match statements. Patch by Pablo Galindo

gh-93662 [https://github.com/python/cpython/issues/93662]: Make sure that the end column offsets are correct in multi-line method calls. Previously, the end column could precede the column offset.

gh-93461 [https://github.com/python/cpython/issues/93461]: importlib.invalidate_caches() now drops entries from sys.path_importer_cache with a relative path as name. This solves a caching issue when a process changes its current working directory.

FileFinder no longer inserts a dot in the path, e.g. /egg/./spam is now /egg/spam.

gh-93621 [https://github.com/python/cpython/issues/93621]: Change order of bytecode instructions emitted for with and async with to reduce the number of entries in the exception table.

gh-93533 [https://github.com/python/cpython/issues/93533]: Reduce the size of the inline cache for LOAD_METHOD by 2 bytes.

gh-93444 [https://github.com/python/cpython/issues/93444]: Removed redundant fields from the compiler’s basicblock struct: b_nofallthrough, b_exit, b_return. They can be easily calculated from the opcode of the last instruction of the block.

gh-93429 [https://github.com/python/cpython/issues/93429]: LOAD_METHOD instruction has been removed. It was merged back into LOAD_ATTR.

gh-93418 [https://github.com/python/cpython/issues/93418]: Fixed an assert where an f-string has an equal sign ‘=’ following an expression, but there’s no trailing brace. For example, f”{i=”.

gh-93382 [https://github.com/python/cpython/issues/93382]: Cache the result of PyCode_GetCode() function to restore the O(1) lookup of the co_code attribute.

gh-93359 [https://github.com/python/cpython/issues/93359]: Ensure that custom ast nodes without explicit end positions can be compiled. Patch by Pablo Galindo.

gh-93356 [https://github.com/python/cpython/issues/93356]: Code for exception handlers is emitted at the end of the code unit’s bytecode. This avoids one jump when no exception is raised.

gh-93354 [https://github.com/python/cpython/issues/93354]: Use exponential backoff for specialization counters in the interpreter. Can reduce the number of failed specializations significantly and avoid slowdown for those parts of a program that are not suitable for specialization.

gh-93283 [https://github.com/python/cpython/issues/93283]: Improve error message for invalid syntax of conversion character in f-string expressions.

gh-93345 [https://github.com/python/cpython/issues/93345]: Fix a crash in substitution of a TypeVar in nested generic alias after TypeVarTuple.

gh-93223 [https://github.com/python/cpython/issues/93223]: When a bytecode instruction jumps to an unconditional jump instruction, the first instruction can often be optimized to target the unconditional jump’s target directly. For tracing reasons, this would previously only occur if both instructions have the same line number. This also now occurs if the unconditional jump is artificial, i.e., if it has no associated line number.

gh-84694 [https://github.com/python/cpython/issues/84694]: The --experimental-isolated-subinterpreters configure option and EXPERIMENTAL_ISOLATED_SUBINTERPRETERS macro have been removed.

gh-91924 [https://github.com/python/cpython/issues/91924]: Fix __lltrace__ debug feature if the stdout encoding is not UTF-8. Patch by Victor Stinner.

gh-93040 [https://github.com/python/cpython/issues/93040]: Wraps unused parameters in Objects/obmalloc.c with Py_UNUSED.

gh-93143 [https://github.com/python/cpython/issues/93143]: Avoid NULL checks for uninitialized local variables by determining at compile time which variables must be initialized.

gh-93061 [https://github.com/python/cpython/issues/93061]: Backward jumps after async for loops are no longer given dubious line numbers.

gh-93065 [https://github.com/python/cpython/issues/93065]: Fix contextvars HAMT implementation to handle iteration over deep trees.

The bug was discovered and fixed by Eli Libman. See MagicStack/immutables#84 [https://github.com/MagicStack/immutables/issues/84] for more details.

gh-93012 [https://github.com/python/cpython/issues/93012]: Added the new function PyType_FromMetaclass(), which generalizes the existing PyType_FromModuleAndSpec() using an additional metaclass argument. This is useful for language binding tools, where it can be used to intercept type-related operations like subclassing or static attribute access by specifying a metaclass with custom slots.

Importantly, PyType_FromMetaclass() is available in the Limited API, which provides a path towards migrating more binding tools onto the Stable ABI.

gh-93021 [https://github.com/python/cpython/issues/93021]: Fix the __text_signature__ for __get__() methods implemented in C. Patch by Jelle Zijlstra.

gh-89914 [https://github.com/python/cpython/issues/89914]: The operand of the YIELD_VALUE instruction is set to the stack depth. This is done to help frame handling on yield and may assist debuggers.

gh-92955 [https://github.com/python/cpython/issues/92955]: Fix memory leak in code object’s lines and positions iterators as they were not finalized at exit. Patch by Kumar Aditya.

gh-92930 [https://github.com/python/cpython/issues/92930]: Fixed a crash in _pickle.c from mutating collections during __reduce__ or persistent_id.

gh-90690 [https://github.com/python/cpython/issues/90690]: The PRECALL instruction has been removed. It offered only a small advantage for specialization and is not needed in the vast majority of cases.

gh-92914 [https://github.com/python/cpython/issues/92914]: Always round the allocated size for lists up to the nearest even number.

gh-92858 [https://github.com/python/cpython/issues/92858]: Improve error message for some suites with syntax error before ‘:’

gh-90473 [https://github.com/python/cpython/issues/90473]: Decrease default recursion limit on WASI to address limited call stack size.

gh-92804 [https://github.com/python/cpython/issues/92804]: Fix memory leak in memoryview iterator as it was not finalized at exit. Patch by Kumar Aditya.

gh-92777 [https://github.com/python/cpython/issues/92777]: Specialize LOAD_METHOD for objects with lazy dictionaries. Patch by Ken Jin.

gh-92658 [https://github.com/python/cpython/issues/92658]: Add support for connecting and binding to Hyper-V sockets on Windows Hyper-V hosts and guests.

gh-92236 [https://github.com/python/cpython/issues/92236]: Remove spurious “LINE” event when starting a generator or coroutine, visible tracing functions implemented in C.

gh-91102 [https://github.com/python/cpython/issues/91102]: _warnings.warn_explicit() is ported to Argument Clinic.

gh-92619 [https://github.com/python/cpython/issues/92619]: Make the compiler duplicate an exit block only if none of its instructions have a lineno (previously only the first instruction in the block was checked, leading to unnecessarily duplicated blocks).

gh-88750 [https://github.com/python/cpython/issues/88750]: The deprecated debug build only PYTHONTHREADDEBUG environment variable no longer does anything.

gh-92261 [https://github.com/python/cpython/issues/92261]: Fix hang when trying to iterate over a typing.Union.

gh-91432 [https://github.com/python/cpython/issues/91432]: Specialized the FOR_ITER opcode using the PEP 659 machinery

gh-91399 [https://github.com/python/cpython/issues/91399]: Removed duplicate ‘{0, 0, 0, 0, 0, 0}’ entry in ‘Objects/unicodetype_db.h’.

gh-91578 [https://github.com/python/cpython/issues/91578]: Updates the error message for abstract class.

bpo-47091 [https://bugs.python.org/issue?@action=redirect&bpo=47091]: Improve performance of repetition of list and tuple by using memcpy to copy data and performing the reference increments in one step.

bpo-46142 [https://bugs.python.org/issue?@action=redirect&bpo=46142]: Make --help output shorter by moving some info to the new --help-env and --help-xoptions command-line options. Also add --help-all option to print complete usage.

bpo-42316 [https://bugs.python.org/issue?@action=redirect&bpo=42316]: Document some places where an assignment expression needs parentheses.

Library

gh-89237 [https://github.com/python/cpython/issues/89237]: Fix hang on Windows in subprocess.wait_closed() in asyncio with ProactorEventLoop. Patch by Kumar Aditya.

gh-97928 [https://github.com/python/cpython/issues/97928]: tkinter.Text.count() raises now an exception for options starting with “-” instead of silently ignoring them.

gh-98393 [https://github.com/python/cpython/issues/98393]: The os module no longer accepts bytes-like paths, like bytearray and memoryview types: only the exact bytes type is accepted for bytes strings. Patch by Victor Stinner.

gh-98363 [https://github.com/python/cpython/issues/98363]: Added itertools.batched() to batch data into lists of a given length with the last list possibly being shorter than the others.

gh-98331 [https://github.com/python/cpython/issues/98331]: Update the bundled copies of pip and setuptools to versions 22.3 and 65.5.0 respectively.

gh-98307 [https://github.com/python/cpython/issues/98307]: A createSocket() method was added to SysLogHandler.

gh-96035 [https://github.com/python/cpython/issues/96035]: Fix bug in urllib.parse.urlparse() that causes certain port numbers containing whitespace, underscores, plus and minus signs, or non-ASCII digits to be incorrectly accepted.

gh-98257 [https://github.com/python/cpython/issues/98257]: Make sys.setprofile() and sys.settrace() functions reentrant. They can no long fail with: RuntimeError("Cannot install a trace function while another trace function is being installed"). Patch by Victor Stinner.

gh-98251 [https://github.com/python/cpython/issues/98251]: Allow venv to pass along PYTHON* variables to ensurepip and pip when they do not impact path resolution

gh-94597 [https://github.com/python/cpython/issues/94597]: Deprecated asyncio.AbstractEventLoopPolicy.get_child_watcher() and asyncio.AbstractEventLoopPolicy.set_child_watcher() methods to be removed in Python 3.14. Patch by Kumar Aditya.

gh-98178 [https://github.com/python/cpython/issues/98178]: On macOS, fix a crash in syslog.syslog() in multi-threaded applications. On macOS, the libc syslog() function is not thread-safe, so syslog.syslog() no longer releases the GIL to call it. Patch by Victor Stinner.

gh-44098 [https://github.com/python/cpython/issues/44098]: Release the GIL when creating mmap.mmap objects on Unix.

gh-87730 [https://github.com/python/cpython/issues/87730]: Wrap network errors consistently in urllib FTP support, so the test suite doesn’t fail when a network is available but the public internet is not reachable.

gh-94597 [https://github.com/python/cpython/issues/94597]: The child watcher classes MultiLoopChildWatcher, FastChildWatcher and SafeChildWatcher are deprecated and will be removed in Python 3.14. Patch by Kumar Aditya.

gh-98023 [https://github.com/python/cpython/issues/98023]: Change default child watcher to PidfdChildWatcher on Linux systems which supports it. Patch by Kumar Aditya.

gh-90985 [https://github.com/python/cpython/issues/90985]: Earlier in 3.11 we deprecated asyncio.Task.cancel("message"). We realized we were too harsh, and have undeprecated it.

gh-65961 [https://github.com/python/cpython/issues/65961]: Do not rely solely on __cached__ on modules; code will also support __spec__.cached.

gh-97646 [https://github.com/python/cpython/issues/97646]: Replace deprecated application/javascript with text/javascript in mimetypes. See RFC 9239 [https://datatracker.ietf.org/doc/html/rfc9239.html]. Patch by Noam Cohen.

gh-97930 [https://github.com/python/cpython/issues/97930]: Apply changes from importlib_resources 5.8 and 5.9: Traversable.joinpath provides a concrete implementation. as_file now supports directories of resources.

gh-97850 [https://github.com/python/cpython/issues/97850]: Remove deprecated importlib.util.set_loader() and importlib.util.module_for_loader() from importlib.util.

gh-97837 [https://github.com/python/cpython/issues/97837]: Change deprecate warning message in unittest from

It is deprecated to return a value!=None

to

It is deprecated to return a value that is not None from a test case

gh-97825 [https://github.com/python/cpython/issues/97825]: Fixes AttributeError when subprocess.check_output() is used with argument input=None and either of the arguments encoding or errors are used.

gh-97008 [https://github.com/python/cpython/issues/97008]: NameError and AttributeError spelling suggestions provided since gh-82711 [https://github.com/python/cpython/issues/82711] are now also emitted by the pure Python traceback module. Tests for those suggestions now exercise both implementations to ensure they are equivalent. Patch by Carl Friedrich Bolz-Tereick and Łukasz Langa.

gh-97799 [https://github.com/python/cpython/issues/97799]: dataclass now uses inspect.get_annotations() to examine the annotations on class objects.

gh-97781 [https://github.com/python/cpython/issues/97781]: Removed deprecated interfaces in importlib.metadata (entry points accessed as dictionary, implicit dictionary construction of sequence of EntryPoint objects, mutablility of EntryPoints result, access of entry point by index). entry_points now has a simpler, more straightforward API (returning EntryPoints).

gh-96827 [https://github.com/python/cpython/issues/96827]: Avoid spurious tracebacks from asyncio when default executor cleanup is delayed until after the event loop is closed (e.g. as the result of a keyboard interrupt).

gh-95534 [https://github.com/python/cpython/issues/95534]: gzip.GzipFile.read() reads 10% faster.

gh-97592 [https://github.com/python/cpython/issues/97592]: Avoid a crash in the C version of asyncio.Future.remove_done_callback() when an evil argument is passed.

gh-97639 [https://github.com/python/cpython/issues/97639]: Remove tokenize.NL check from tabnanny.

gh-97545 [https://github.com/python/cpython/issues/97545]: Make Semaphore run faster.

gh-73588 [https://github.com/python/cpython/issues/73588]: Fix generation of the default name of tkinter.Checkbutton. Previously, checkbuttons in different parent widgets could have the same short name and share the same state if arguments “name” and “variable” are not specified. Now they are globally unique.

gh-96865 [https://github.com/python/cpython/issues/96865]: fix Flag to use boundary CONFORM

This restores previous Flag behavior of allowing flags with non-sequential values to be combined; e.g.

class Skip(Flag): TWO = 2 EIGHT = 8

Skip.TWO | Skip.EIGHT -> <Skip.TWO|EIGHT: 10>

gh-97005 [https://github.com/python/cpython/issues/97005]: Update bundled libexpat to 2.4.9

gh-85760 [https://github.com/python/cpython/issues/85760]: Fix race condition in asyncio where process_exited() called before the pipe_data_received() leading to inconsistent output. Patch by Kumar Aditya.

gh-96704 [https://github.com/python/cpython/issues/96704]: Pass the correct contextvars.Context when a asyncio exception handler is called on behalf of a task or callback handle. This adds a new Task method, get_context, and also a new Handle method with the same name. If this method is not found on a task object (perhaps because it is a third-party library that does not yet provide this method), the context prevailing at the time the exception handler is called is used.

gh-96819 [https://github.com/python/cpython/issues/96819]: Fixed check in multiprocessing.resource_tracker that guarantees that the length of a write to a pipe is not greater than PIPE_BUF.

gh-95865 [https://github.com/python/cpython/issues/95865]: Reduce urllib.parse.quote_from_bytes() memory use on large values.

Contributed by Dennis Sweeney.

gh-96741 [https://github.com/python/cpython/issues/96741]: Corrected type annotation for dataclass attribute pstats.FunctionProfile.ncalls to be str.

gh-96734 [https://github.com/python/cpython/issues/96734]: Update unicodedata database to Unicode 15.0.0.

gh-96735 [https://github.com/python/cpython/issues/96735]: Fix undefined behaviour in struct.unpack().

gh-46412 [https://github.com/python/cpython/issues/46412]: Improve performance of bool(db) for large ndb/gdb databases. Previously this would call len(db) which would iterate over all keys – the answer (empty or not) is known after the first key.

gh-96652 [https://github.com/python/cpython/issues/96652]: Fix the faulthandler implementation of faulthandler.register(signal, chain=True) if the sigaction() function is not available: don’t call the previous signal handler if it’s NULL. Patch by Victor Stinner.

gh-68163 [https://github.com/python/cpython/issues/68163]: Correct conversion of numbers.Rational’s to float.

gh-96538 [https://github.com/python/cpython/issues/96538]: Speed up bisect.bisect() functions by taking advantage of type-stability.

gh-96465 [https://github.com/python/cpython/issues/96465]: Fraction hashes are now cached.

gh-96079 [https://github.com/python/cpython/issues/96079]: In typing, fix missing field name and incorrect __module__ in _AnnotatedAlias.

gh-96415 [https://github.com/python/cpython/issues/96415]: Remove types._cell_factory from module namespace.

gh-95987 [https://github.com/python/cpython/issues/95987]: Fix repr of Any subclasses.

gh-96388 [https://github.com/python/cpython/issues/96388]: Work around missing socket functions in socket’s __repr__.

gh-96385 [https://github.com/python/cpython/issues/96385]: Fix TypeVarTuple.__typing_prepare_subst__. TypeError was not raised when using more than one TypeVarTuple, like [*T, *V] in type alias substitutions.

gh-96142 [https://github.com/python/cpython/issues/96142]: Add match_args, kw_only, slots, and weakref_slot to _DataclassParams.

gh-96073 [https://github.com/python/cpython/issues/96073]: In inspect, fix overeager replacement of “typing.” in formatting annotations.

gh-89258 [https://github.com/python/cpython/issues/89258]: Added a getChildren() method to logging.Logger, to get the immediate child loggers of a logger.

gh-96346 [https://github.com/python/cpython/issues/96346]: Use double caching for compiled RE patterns.

gh-96349 [https://github.com/python/cpython/issues/96349]: Fixed a minor performance regression in threading.Event.__init__()

gh-90467 [https://github.com/python/cpython/issues/90467]: Fix asyncio.streams.StreamReaderProtocol to keep a strong reference to the created task, so that it’s not garbage collected

gh-96172 [https://github.com/python/cpython/issues/96172]: Fix a bug in unicodedata: east_asian_width used to return the wrong value for unassigned characters; and for yet unassigned, but reserved characters.

gh-96159 [https://github.com/python/cpython/issues/96159]: Fix a performance regression in logging TimedRotatingFileHandler. Only check for special files when the rollover time has passed.

gh-96175 [https://github.com/python/cpython/issues/96175]: Fix unused localName parameter in the Attr class in xml.dom.minidom.

gh-96145 [https://github.com/python/cpython/issues/96145]: Add AttrDict to JSON module for use with object_hook.

gh-96052 [https://github.com/python/cpython/issues/96052]: Fix handling compiler warnings (SyntaxWarning and DeprecationWarning) in codeop.compile_command() when checking for incomplete input. Previously it emitted warnings and raised a SyntaxError. Now it always returns None for incomplete input without emitting any warnings.

gh-96125 [https://github.com/python/cpython/issues/96125]: Fix incorrect condition that causes sys.thread_info.name to be wrong on pthread platforms.

gh-96019 [https://github.com/python/cpython/issues/96019]: Fix a bug in the makeunicodedata.py script leading to about 13 KiB of space saving in the unicodedata module, specifically the character decomposition data.

gh-95463 [https://github.com/python/cpython/issues/95463]: Remove an incompatible change from bpo-28080 [https://bugs.python.org/issue?@action=redirect&bpo=28080] that caused a regression that ignored the utf8 in ZipInfo.flag_bits. Patch by Pablo Galindo.

gh-69142 [https://github.com/python/cpython/issues/69142]: Add %:z strftime format code (generates tzoffset with colons as separator), see strftime() and strptime() Behavior.

gh-95899 [https://github.com/python/cpython/issues/95899]: Fix asyncio.Runner to call asyncio.set_event_loop() only once to avoid calling attach_loop() multiple times on child watchers. Patch by Kumar Aditya.

gh-95736 [https://github.com/python/cpython/issues/95736]: Fix unittest.IsolatedAsyncioTestCase to set event loop before calling setup functions. Patch by Kumar Aditya.

gh-95865 [https://github.com/python/cpython/issues/95865]: Speed up urllib.parse.quote_from_bytes() by replacing a list comprehension with map().

gh-95861 [https://github.com/python/cpython/issues/95861]: Add support for computing Spearman’s correlation coefficient to the existing statistics.correlation() function.

gh-95804 [https://github.com/python/cpython/issues/95804]: Fix logging shutdown handler so it respects MemoryHandler.flushOnClose.

gh-95704 [https://github.com/python/cpython/issues/95704]: When a task catches asyncio.CancelledError and raises some other error, the other error should generally not silently be suppressed.

gh-95149 [https://github.com/python/cpython/issues/95149]: The HTTPStatus enum offers a couple of properties to indicate the HTTP status category e.g. HTTPStatus.OK.is_success.

gh-95609 [https://github.com/python/cpython/issues/95609]: Update bundled pip to 22.2.2.

gh-95289 [https://github.com/python/cpython/issues/95289]: Fix asyncio.TaskGroup to propagate exception when asyncio.CancelledError was replaced with another exception by a context manager. Patch by Kumar Aditya and Guido van Rossum.

gh-94909 [https://github.com/python/cpython/issues/94909]: Fix incorrect joining of relative Windows paths with drives in pathlib.PurePath initializer.

gh-95385 [https://github.com/python/cpython/issues/95385]: Faster json.dumps() when sorting of keys is not requested (default).

gh-83901 [https://github.com/python/cpython/issues/83901]: Improve Signature.bind error message for missing keyword-only arguments.

gh-95339 [https://github.com/python/cpython/issues/95339]: Update bundled pip to 22.2.1.

gh-95045 [https://github.com/python/cpython/issues/95045]: Fix GC crash when deallocating _lsprof.Profiler by untracking it before calling any callbacks. Patch by Kumar Aditya.

gh-95231 [https://github.com/python/cpython/issues/95231]: Fail gracefully if EPERM or ENOSYS is raised when loading crypt methods. This may happen when trying to load MD5 on a Linux kernel with FIPS enabled.

gh-95097 [https://github.com/python/cpython/issues/95097]: Fix asyncio.run() for asyncio.Task implementations without uncancel() method. Patch by Kumar Aditya.

gh-95087 [https://github.com/python/cpython/issues/95087]: Fix IndexError in parsing invalid date in the email module.

gh-95199 [https://github.com/python/cpython/issues/95199]: Upgrade bundled setuptools to 63.2.0.

gh-95194 [https://github.com/python/cpython/issues/95194]: Upgrade bundled pip to 22.2.

gh-93899 [https://github.com/python/cpython/issues/93899]: Fix check for existence of os.EFD_CLOEXEC, os.EFD_NONBLOCK and os.EFD_SEMAPHORE flags on older kernel versions where these flags are not present. Patch by Kumar Aditya.

gh-95166 [https://github.com/python/cpython/issues/95166]: Fix concurrent.futures.Executor.map() to cancel the currently waiting on future on an error - e.g. TimeoutError or KeyboardInterrupt.

gh-95132 [https://github.com/python/cpython/issues/95132]: Fix a sqlite3 regression where *args and **kwds were incorrectly relayed from connect() to the Connection factory. The regression was introduced in 3.11a1 with PR 24421 (gh-85128 [https://github.com/python/cpython/issues/85128]). Patch by Erlend E. Aasland.

gh-93157 [https://github.com/python/cpython/issues/93157]: Fix fileinput module didn’t support errors option when inplace is true.

gh-91212 [https://github.com/python/cpython/issues/91212]: Fixed flickering of the turtle window when the tracer is turned off. Patch by Shin-myoung-serp.

gh-95077 [https://github.com/python/cpython/issues/95077]: Add deprecation warning for enum member.member access (e.g. Color.RED.BLUE). Remove EnumMeta.__getattr__.

gh-95109 [https://github.com/python/cpython/issues/95109]: Ensure that timeouts scheduled with asyncio.Timeout that have already expired are delivered promptly.

gh-95105 [https://github.com/python/cpython/issues/95105]: wsgiref.types.InputStream.__iter__() should return Iterator[bytes], not Iterable[bytes]. Patch by Shantanu Jain.

gh-95066 [https://github.com/python/cpython/issues/95066]: Replaced assert with exception in ast.parse(), when feature_version has an invalid major version. Patch by Shantanu Jain.

gh-77617 [https://github.com/python/cpython/issues/77617]: Add sqlite3 command-line interface. Patch by Erlend Aasland.

gh-95005 [https://github.com/python/cpython/issues/95005]: Replace _PyAccu with _PyUnicodeWriter in JSON encoder and StringIO and remove the _PyAccu implementation.

gh-90085 [https://github.com/python/cpython/issues/90085]: Remove -c/--clock and -t/--time CLI options of timeit. The options had been deprecated since Python 3.3 and the functionality was removed in Python 3.7. Patch by Shantanu Jain.

gh-94857 [https://github.com/python/cpython/issues/94857]: Fix refleak in _io.TextIOWrapper.reconfigure. Patch by Kumar Aditya.

gh-94821 [https://github.com/python/cpython/issues/94821]: Fix binding of unix socket to empty address on Linux to use an available address from the abstract namespace, instead of “0”.

gh-94736 [https://github.com/python/cpython/issues/94736]: Fix crash when deallocating an instance of a subclass of _multiprocessing.SemLock. Patch by Kumar Aditya.

gh-81620 [https://github.com/python/cpython/issues/81620]: Add random.binomialvariate().

gh-74116 [https://github.com/python/cpython/issues/74116]: Allow asyncio.StreamWriter.drain() to be awaited concurrently by multiple tasks. Patch by Kumar Aditya.

gh-87822 [https://github.com/python/cpython/issues/87822]: When called with capture_locals=True, the traceback module functions swallow exceptions raised from calls to repr() on local variables of frames. This is in order to prioritize the original exception over rendering errors. An indication of the failure is printed in place of the missing value. (Patch by Simon-Martin Schroeder).

gh-88050 [https://github.com/python/cpython/issues/88050]: Fix asyncio subprocess transport to kill process cleanly when process is blocked and avoid RuntimeError when loop is closed. Patch by Kumar Aditya.

gh-94637 [https://github.com/python/cpython/issues/94637]: SSLContext.set_default_verify_paths() now releases the GIL around SSL_CTX_set_default_verify_paths call. The function call performs I/O and CPU intensive work.

gh-94309 [https://github.com/python/cpython/issues/94309]: Deprecate aliases typing.Hashable and typing.Sized

gh-92546 [https://github.com/python/cpython/issues/92546]: An undocumented python -m pprint benchmark is moved into pprint suite of pyperformance. Patch by Oleg Iarygin.

gh-94607 [https://github.com/python/cpython/issues/94607]: Fix subclassing complex generics with type variables in typing. Previously an error message saying Some type variables ... are not listed in Generic[...] was shown. typing no longer populates __parameters__ with the __parameters__ of a Python class.

gh-94619 [https://github.com/python/cpython/issues/94619]: Remove the long-deprecated module_repr() from importlib.

gh-93910 [https://github.com/python/cpython/issues/93910]: The ability to access the other values of an enum on an enum (e.g. Color.RED.BLUE) has been restored in order to fix a performance regression.

gh-93896 [https://github.com/python/cpython/issues/93896]: Fix asyncio.run() and unittest.IsolatedAsyncioTestCase to always the set event loop as it was done in Python 3.10 and earlier. Patch by Kumar Aditya.

gh-94343 [https://github.com/python/cpython/issues/94343]: Allow setting the attributes of reprlib.Repr during object initialization

gh-94382 [https://github.com/python/cpython/issues/94382]: Port static types of _multiprocessing module to heap types. Patch by Kumar Aditya.

gh-78724 [https://github.com/python/cpython/issues/78724]: Fix crash in struct.Struct when it was not completely initialized by initializing it in __new__(). Patch by Kumar Aditya.

gh-94510 [https://github.com/python/cpython/issues/94510]: Re-entrant calls to sys.setprofile() and sys.settrace() now raise RuntimeError. Patch by Pablo Galindo.

gh-92336 [https://github.com/python/cpython/issues/92336]: Fix bug where linecache.getline() fails on bad files with UnicodeDecodeError or SyntaxError. It now returns an empty string as per the documentation.

gh-94398 [https://github.com/python/cpython/issues/94398]: Once a asyncio.TaskGroup has started shutting down (i.e., at least one task has failed and the task group has started cancelling the remaining tasks), it should not be possible to add new tasks to the task group.

gh-94383 [https://github.com/python/cpython/issues/94383]: xml.etree: Remove the ElementTree.Element.copy() method of the pure Python implementation, deprecated in Python 3.10, use the copy.copy() function instead. The C implementation of xml.etree has no copy() method, only a __copy__() method. Patch by Victor Stinner.

gh-94379 [https://github.com/python/cpython/issues/94379]: zipimport: Remove find_loader() and find_module() methods, deprecated in Python 3.10: use the find_spec() method instead. See PEP 451 [https://peps.python.org/pep-0451/] for the rationale. Patch by Victor Stinner.

gh-94352 [https://github.com/python/cpython/issues/94352]: shlex.split(): Passing None for s argument now raises an exception, rather than reading sys.stdin. The feature was deprecated in Python 3.9. Patch by Victor Stinner.

gh-94318 [https://github.com/python/cpython/issues/94318]: Strip trailing spaces in pydoc text output.

gh-89988 [https://github.com/python/cpython/issues/89988]: Fix memory leak in pickle.Pickler when looking up dispatch_table. Patch by Kumar Aditya.

gh-90016 [https://github.com/python/cpython/issues/90016]: Deprecate sqlite3 default adapters and converters. Patch by Erlend E. Aasland.

gh-94254 [https://github.com/python/cpython/issues/94254]: Fixed types of struct module to be immutable. Patch by Kumar Aditya.

gh-93259 [https://github.com/python/cpython/issues/93259]: Now raise ValueError when None or an empty string are passed to Distribution.from_name (and other callers).

gh-74696 [https://github.com/python/cpython/issues/74696]: shutil.make_archive() now passes the root_dir argument to custom archivers which support it.

gh-94216 [https://github.com/python/cpython/issues/94216]: The dis module now has the opcodes for pseudo instructions (those which are used by the compiler during code generation but then removed or replaced by real opcodes before the final bytecode is emitted).

gh-93096 [https://github.com/python/cpython/issues/93096]: Removed undocumented python -m codecs. Use python -m unittest test.test_codecs.EncodedFileTest instead.

gh-94207 [https://github.com/python/cpython/issues/94207]: Made _struct.Struct GC-tracked in order to fix a reference leak in the _struct module.

gh-93096 [https://github.com/python/cpython/issues/93096]: Removed undocumented -t argument of python -m base64. Use python -m unittest test.test_base64.LegacyBase64TestCase.test_encodebytes instead.

gh-94226 [https://github.com/python/cpython/issues/94226]: Remove the locale.format() function, deprecated in Python 3.7: use locale.format_string() instead. Patch by Victor Stinner.

gh-94199 [https://github.com/python/cpython/issues/94199]: Remove the ssl.match_hostname() function. The ssl.match_hostname() was deprecated in Python 3.7. OpenSSL performs hostname matching since Python 3.7, Python no longer uses the ssl.match_hostname() function. Patch by Victor Stinner.

gh-94214 [https://github.com/python/cpython/issues/94214]: Document the context object used in the venv.EnvBuilder class, and add the new environment’s library path to it.

gh-94199 [https://github.com/python/cpython/issues/94199]: Remove the ssl.wrap_socket() function, deprecated in Python 3.7: instead, create a ssl.SSLContext object and call its ssl.SSLContext.wrap_socket method. Any package that still uses ssl.wrap_socket() is broken and insecure. The function neither sends a SNI TLS extension nor validates server hostname. Code is subject to CWE 295 [https://cwe.mitre.org/data/definitions/295.html] Improper Certificate Validation. Patch by Victor Stinner.

gh-94199 [https://github.com/python/cpython/issues/94199]: Remove the ssl.RAND_pseudo_bytes() function, deprecated in Python 3.6: use os.urandom() or ssl.RAND_bytes() instead. Patch by Victor Stinner.

gh-94199 [https://github.com/python/cpython/issues/94199]: hashlib: Remove the pure Python implementation of hashlib.pbkdf2_hmac(), deprecated in Python 3.10. Python 3.10 and newer requires OpenSSL 1.1.1 (PEP 644 [https://peps.python.org/pep-0644/]): this OpenSSL version provides a C implementation of pbkdf2_hmac() which is faster. Patch by Victor Stinner.

gh-94196 [https://github.com/python/cpython/issues/94196]: gzip: Remove the filename attribute of gzip.GzipFile, deprecated since Python 2.6, use the name attribute instead. In write mode, the filename attribute added '.gz' file extension if it was not present. Patch by Victor Stinner.

gh-94182 [https://github.com/python/cpython/issues/94182]: run the asyncio.PidfdChildWatcher on the running loop, this allows event loops to run subprocesses when there is no default event loop running on the main thread

gh-94169 [https://github.com/python/cpython/issues/94169]: Remove io.OpenWrapper and _pyio.OpenWrapper, deprecated in Python 3.10: just use open() instead. The open() (io.open()) function is a built-in function. Since Python 3.10, _pyio.open() is also a static method. Patch by Victor Stinner.

gh-91742 [https://github.com/python/cpython/issues/91742]: Fix pdb crash after jump caused by a null pointer dereference. Patch by Kumar Aditya.

gh-94101 [https://github.com/python/cpython/issues/94101]: Manual instantiation of ssl.SSLSession objects is no longer allowed as it lead to misconfigured instances that crashed the interpreter when attributes where accessed on them.

gh-84753 [https://github.com/python/cpython/issues/84753]: inspect.iscoroutinefunction(), inspect.isgeneratorfunction(), and inspect.isasyncgenfunction() now properly return True for duck-typed function-like objects like instances of unittest.mock.AsyncMock.

This makes inspect.iscoroutinefunction() consistent with the behavior of asyncio.iscoroutinefunction(). Patch by Mehdi ABAAKOUK.

gh-94028 [https://github.com/python/cpython/issues/94028]: Fix a regression in the sqlite3 where statement objects were not properly cleared and reset after use in cursor iters. The regression was introduced by PR 27884 in Python 3.11a1. Patch by Erlend E. Aasland.

gh-93973 [https://github.com/python/cpython/issues/93973]: Add keyword argument all_errors to asyncio.create_connection so that multiple connection errors can be raised as an ExceptionGroup.

gh-93963 [https://github.com/python/cpython/issues/93963]: Officially deprecate from importlib.abc classes moved to importlib.resources.abc.

gh-93858 [https://github.com/python/cpython/issues/93858]: Prevent error when activating venv in nested fish instances.

gh-93820 [https://github.com/python/cpython/issues/93820]: Pickle enum.Flag by name.

gh-93847 [https://github.com/python/cpython/issues/93847]: Fix repr of enum of generic aliases.

gh-91404 [https://github.com/python/cpython/issues/91404]: Revert the re memory leak when a match is terminated by a signal or memory allocation failure as the implemented fix caused a major performance regression.

gh-83499 [https://github.com/python/cpython/issues/83499]: Fix double closing of file description in tempfile.

gh-93820 [https://github.com/python/cpython/issues/93820]: Fixed a regression when copy.copy()-ing enum.Flag with multiple flag members.

gh-79512 [https://github.com/python/cpython/issues/79512]: Fixed names and __module__ value of weakref classes ReferenceType, ProxyType, CallableProxyType. It makes them pickleable.

gh-91389 [https://github.com/python/cpython/issues/91389]: Fix an issue where dis utilities could report missing or incorrect position information in the presence of CACHE entries.

gh-93626 [https://github.com/python/cpython/issues/93626]: Set __future__.annotations to have a None mandatoryRelease to indicate that it is currently ‘TBD’.

gh-90473 [https://github.com/python/cpython/issues/90473]: Emscripten and WASI have no home directory and cannot provide PEP 370 [https://peps.python.org/pep-0370/] user site directory.

gh-90494 [https://github.com/python/cpython/issues/90494]: copy.copy() and copy.deepcopy() now always raise a TypeError if __reduce__() returns a tuple with length 6 instead of silently ignore the 6th item or produce incorrect result.

gh-90549 [https://github.com/python/cpython/issues/90549]: Fix a multiprocessing bug where a global named resource (such as a semaphore) could leak when a child process is spawned (as opposed to forked).

gh-93521 [https://github.com/python/cpython/issues/93521]: Fixed a case where dataclasses would try to add __weakref__ into the __slots__ for a dataclass that specified weakref_slot=True when it was already defined in one of its bases. This resulted in a TypeError upon the new class being created.

gh-79579 [https://github.com/python/cpython/issues/79579]: sqlite3 now correctly detects DML queries with leading comments. Patch by Erlend E. Aasland.

gh-93421 [https://github.com/python/cpython/issues/93421]: Update sqlite3.Cursor.rowcount when a DML statement has run to completion. This fixes the row count for SQL queries like UPDATE ... RETURNING. Patch by Erlend E. Aasland.

gh-93475 [https://github.com/python/cpython/issues/93475]: Expose FICLONE and FICLONERANGE constants in fcntl. Patch by Illia Volochii.

gh-93370 [https://github.com/python/cpython/issues/93370]: Deprecate version and version_info.

gh-91810 [https://github.com/python/cpython/issues/91810]: Suppress writing an XML declaration in open files in ElementTree.write() with encoding='unicode' and xml_declaration=None.

gh-91162 [https://github.com/python/cpython/issues/91162]: Support splitting of unpacked arbitrary-length tuple over TypeVar and TypeVarTuple parameters. For example:

A[T, *Ts][*tuple[int, ...]] -> A[int, *tuple[int, ...]]

A[*Ts, T][*tuple[int, ...]] -> A[*tuple[int, ...], int]

gh-93353 [https://github.com/python/cpython/issues/93353]: Fix the importlib.resources.as_file() context manager to remove the temporary file if destroyed late during Python finalization: keep a local reference to the os.remove() function. Patch by Victor Stinner.

gh-83658 [https://github.com/python/cpython/issues/83658]: Make multiprocessing.Pool raise an exception if maxtasksperchild is not None or a positive int.

gh-93312 [https://github.com/python/cpython/issues/93312]: Add os.PIDFD_NONBLOCK flag to open a file descriptor for a process with os.pidfd_open() in non-blocking mode. Patch by Kumar Aditya.

gh-88123 [https://github.com/python/cpython/issues/88123]: Implement Enum.__contains__ that returns True or False to replace the deprecated behaviour that would sometimes raise a TypeError.

gh-93297 [https://github.com/python/cpython/issues/93297]: Make asyncio task groups prevent child tasks from being GCed

gh-85308 [https://github.com/python/cpython/issues/85308]: Changed argparse.ArgumentParser to use filesystem encoding and error handler instead of default text encoding to read arguments from file (e.g. fromfile_prefix_chars option). This change affects Windows; argument file should be encoded with UTF-8 instead of ANSI Codepage.

gh-93156 [https://github.com/python/cpython/issues/93156]: Accessing the pathlib.PurePath.parents sequence of an absolute path using negative index values produced incorrect results.

gh-93162 [https://github.com/python/cpython/issues/93162]: Add the ability for logging.config.dictConfig() to usefully configure QueueHandler and QueueListener as a pair, and add logging.getHandlerByName() and logging.getHandlerNames() APIs to allow access to handlers by name.

gh-93243 [https://github.com/python/cpython/issues/93243]: The smtpd module was removed per the schedule in PEP 594 [https://peps.python.org/pep-0594/].

gh-92886 [https://github.com/python/cpython/issues/92886]: Replace assert statements with raise AssertionError() in BaseHandler so that the tested behaviour is maintained running with optimizations (-O).

gh-90155 [https://github.com/python/cpython/issues/90155]: Fix broken asyncio.Semaphore when acquire is cancelled.

gh-90817 [https://github.com/python/cpython/issues/90817]: The locale.resetlocale() function is deprecated and will be removed in Python 3.13. Use locale.setlocale(locale.LC_ALL, "") instead. Patch by Victor Stinner.

gh-91513 [https://github.com/python/cpython/issues/91513]: Added taskName attribute to logging module for use with asyncio tasks.

gh-74696 [https://github.com/python/cpython/issues/74696]: shutil.make_archive() no longer temporarily changes the current working directory during creation of standard .zip or tar archives.

gh-92728 [https://github.com/python/cpython/issues/92728]: The re.template() function and the corresponding re.TEMPLATE and re.T flags are restored after they were removed in 3.11.0b1, but they are now deprecated, so they might be removed from Python 3.13.

gh-93033 [https://github.com/python/cpython/issues/93033]: Search in some strings (platform dependent i.e [U+0xFFFF, U+0x0100] on Windows or [U+0xFFFFFFFF, U+0x00010000] on Linux 64-bit) are now up to 10 times faster.

gh-89973 [https://github.com/python/cpython/issues/89973]: Fix re.error raised in fnmatch if the pattern contains a character range with upper bound lower than lower bound (e.g. [c-a]). Now such ranges are interpreted as empty ranges.

gh-93044 [https://github.com/python/cpython/issues/93044]: No longer convert the database argument of sqlite3.connect() to bytes before passing it to the factory.

gh-93010 [https://github.com/python/cpython/issues/93010]: In a very special case, the email package tried to append the nonexistent InvalidHeaderError to the defect list. It should have been InvalidHeaderDefect.

gh-92986 [https://github.com/python/cpython/issues/92986]: Fix ast.unparse() when ImportFrom.level is None

gh-92932 [https://github.com/python/cpython/issues/92932]: Now dis() and get_instructions() handle operand values for instructions prefixed by EXTENDED_ARG_QUICK. Patch by Sam Gross and Donghee Na.

gh-92675 [https://github.com/python/cpython/issues/92675]: Fix venv.ensure_directories() to accept pathlib.Path arguments in addition to str paths. Patch by David Foster.

gh-87901 [https://github.com/python/cpython/issues/87901]: Removed the encoding argument from os.popen() that was added in 3.11b1.

gh-91922 [https://github.com/python/cpython/issues/91922]: Fix function sqlite.connect() and the sqlite.Connection constructor on non-UTF-8 locales. Also, they now support bytes paths non-decodable with the current FS encoding.

gh-92869 [https://github.com/python/cpython/issues/92869]: Added c_time_t to ctypes, which has the same size as the time_t type in C.

gh-92839 [https://github.com/python/cpython/issues/92839]: Fixed crash resulting from calling bisect.insort() or bisect.insort_left() with the key argument not equal to None.

gh-90473 [https://github.com/python/cpython/issues/90473]: subprocess now fails early on Emscripten and WASI platforms to work around missing os.pipe() on WASI.

gh-89325 [https://github.com/python/cpython/issues/89325]: Removed many old deprecated unittest features: TestCase method aliases, undocumented and broken TestCase method assertDictContainsSubset, undocumented TestLoader.loadTestsFromModule parameter use_load_tests, and an underscored alias of the TextTestResult class.

gh-92734 [https://github.com/python/cpython/issues/92734]: Allow multi-element reprs emitted by reprlib to be pretty-printed using configurable indentation.

gh-92671 [https://github.com/python/cpython/issues/92671]: Fixed ast.unparse() for empty tuples in the assignment target context.

gh-91581 [https://github.com/python/cpython/issues/91581]: utcfromtimestamp() no longer attempts to resolve fold in the pure Python implementation, since the fold is never 1 in UTC. In addition to being slightly faster in the common case, this also prevents some errors when the timestamp is close to datetime.min. Patch by Paul Ganssle.

gh-86388 [https://github.com/python/cpython/issues/86388]: Removed randrange() functionality deprecated since Python 3.10. Formerly, randrange(10.0) losslessly converted to randrange(10). Now, it raises a TypeError. Also, the exception raised for non-integral values such as randrange(10.5) or randrange(‘10’) has been changed from ValueError to TypeError.

gh-90385 [https://github.com/python/cpython/issues/90385]: Add pathlib.Path.walk() as an alternative to os.walk().

gh-92550 [https://github.com/python/cpython/issues/92550]: Fix pathlib.Path.rglob() for empty pattern.

gh-92591 [https://github.com/python/cpython/issues/92591]: Allow logging filters to return a logging.LogRecord instance so that filters attached to logging.Handlers can enrich records without side effects on other handlers.

gh-92445 [https://github.com/python/cpython/issues/92445]: Fix a bug in argparse where nargs="*" would raise an error instead of returning an empty list when 0 arguments were supplied if choice was also defined in parser.add_argument.

gh-92547 [https://github.com/python/cpython/issues/92547]: Remove undocumented sqlite3 features deprecated in Python 3.10:

sqlite3.enable_shared_cache()

sqlite3.OptimizedUnicode

Patch by Erlend E. Aasland.

gh-92530 [https://github.com/python/cpython/issues/92530]: Fix an issue that occurred after interrupting threading.Condition.notify().

gh-92531 [https://github.com/python/cpython/issues/92531]: The statistics.median_grouped() function now always return a float. Formerly, it did not convert the input type when for sequences of length one.

gh-84131 [https://github.com/python/cpython/issues/84131]: The pathlib.Path deprecated method link_to has been removed. Use 3.10’s hardlink_to() method instead as its semantics are consistent with that of symlink_to().

gh-89336 [https://github.com/python/cpython/issues/89336]: Removed configparser module APIs: the SafeConfigParser class alias, the ParsingError.filename property and parameter, and the ConfigParser.readfp method, all of which were deprecated since Python 3.2.

gh-92391 [https://github.com/python/cpython/issues/92391]: Add __class_getitem__() to csv.DictReader and csv.DictWriter, allowing them to be parameterized at runtime. Patch by Marc Mueller.

gh-91968 [https://github.com/python/cpython/issues/91968]: Add SO_RTABLE and SO_USER_COOKIE constants to socket.

gh-91810 [https://github.com/python/cpython/issues/91810]: ElementTree method write() and function tostring() now use the text file’s encoding (“UTF-8” if not available) instead of locale encoding in XML declaration when encoding="unicode" is specified.

gh-81790 [https://github.com/python/cpython/issues/81790]: os.path.splitdrive() now understands DOS device paths with UNC links (beginning \\?\UNC\). Contributed by Barney Gale.

gh-91760 [https://github.com/python/cpython/issues/91760]: Apply more strict rules for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore.

gh-90622 [https://github.com/python/cpython/issues/90622]: Worker processes for concurrent.futures.ProcessPoolExecutor are no longer spawned on demand (a feature added in 3.9) when the multiprocessing context start method is "fork" as that can lead to deadlocks in the child processes due to a fork happening while threads are running.

gh-91577 [https://github.com/python/cpython/issues/91577]: Move imports in SharedMemory methods to module level so that they can be executed late in python finalization.

gh-91581 [https://github.com/python/cpython/issues/91581]: Remove an unhandled error case in the C implementation of calls to datetime.fromtimestamp with no time zone (i.e. getting a local time from an epoch timestamp). This should have no user-facing effect other than giving a possibly more accurate error message when called with timestamps that fall on 10000-01-01 in the local time. Patch by Paul Ganssle.

gh-91539 [https://github.com/python/cpython/issues/91539]: Improve performance of urllib.request.getproxies_environment when there are many environment variables

gh-91524 [https://github.com/python/cpython/issues/91524]: Speed up the regular expression substitution (functions re.sub() and re.subn() and corresponding re.Pattern methods) for replacement strings containing group references by 2–3 times.

gh-91447 [https://github.com/python/cpython/issues/91447]: Fix findtext in the xml module to only give an empty string when the text attribute is set to None.

gh-91456 [https://github.com/python/cpython/issues/91456]: Deprecate current default auto() behavior: In 3.13 the default will be for for auto() to always return the largest member value incremented by 1, and to raise if incompatible value types are used.

bpo-47231 [https://bugs.python.org/issue?@action=redirect&bpo=47231]: Fixed an issue with inconsistent trailing slashes in tarfile longname directories.

bpo-39064 [https://bugs.python.org/issue?@action=redirect&bpo=39064]: zipfile.ZipFile now raises zipfile.BadZipFile instead of ValueError when reading a corrupt zip file in which the central directory offset is negative.

bpo-41287 [https://bugs.python.org/issue?@action=redirect&bpo=41287]: Fix handling of the doc argument in subclasses of property().

gh-90005 [https://github.com/python/cpython/issues/90005]: ctypes dependency libffi is now detected with pkg-config.

bpo-32547 [https://bugs.python.org/issue?@action=redirect&bpo=32547]: The constructors for DictWriter and DictReader now coerce the fieldnames argument to a list if it is an iterator.

bpo-35540 [https://bugs.python.org/issue?@action=redirect&bpo=35540]: Fix dataclasses.asdict() crash when collections.defaultdict is present in the attributes.

bpo-47063 [https://bugs.python.org/issue?@action=redirect&bpo=47063]: Add an index_pages parameter to support using non-default index page names.

bpo-47025 [https://bugs.python.org/issue?@action=redirect&bpo=47025]: Drop support for bytes on sys.path.

bpo-46951 [https://bugs.python.org/issue?@action=redirect&bpo=46951]: Order the contents of zipapp archives, to make builds more reproducible.

bpo-42777 [https://bugs.python.org/issue?@action=redirect&bpo=42777]: Implement pathlib.Path.is_mount() for Windows paths.

bpo-46755 [https://bugs.python.org/issue?@action=redirect&bpo=46755]: In QueueHandler, clear stack_info from LogRecord to prevent stack trace from being written twice.

bpo-45393 [https://bugs.python.org/issue?@action=redirect&bpo=45393]: Fix the formatting for await x and not x in the operator precedence table when using the help() system.

bpo-46642 [https://bugs.python.org/issue?@action=redirect&bpo=46642]: Improve error message when trying to subclass an instance of typing.TypeVar, typing.ParamSpec, typing.TypeVarTuple, etc. Based on patch by Gregory Beauregard.

bpo-46364 [https://bugs.python.org/issue?@action=redirect&bpo=46364]: Restrict use of sockets instead of pipes for stdin of subprocesses created by asyncio to AIX platform only.

bpo-28249 [https://bugs.python.org/issue?@action=redirect&bpo=28249]: Set doctest.DocTest.lineno to None when an object does not have __doc__.

bpo-46197 [https://bugs.python.org/issue?@action=redirect&bpo=46197]: Fix ensurepip environment isolation for subprocess running pip.

bpo-45924 [https://bugs.python.org/issue?@action=redirect&bpo=45924]: Fix asyncio incorrect traceback when future’s exception is raised multiple times. Patch by Kumar Aditya.

bpo-45046 [https://bugs.python.org/issue?@action=redirect&bpo=45046]: Add support of context managers in unittest: methods enterContext() and enterClassContext() of class TestCase, method enterAsyncContext() of class IsolatedAsyncioTestCase and function unittest.enterModuleContext().

bpo-44173 [https://bugs.python.org/issue?@action=redirect&bpo=44173]: Enable fast seeking of uncompressed unencrypted zipfile.ZipExtFile

bpo-42627 [https://bugs.python.org/issue?@action=redirect&bpo=42627]: Fix incorrect parsing of Windows registry proxy settings

bpo-42047 [https://bugs.python.org/issue?@action=redirect&bpo=42047]: Add threading.get_native_id() support for DragonFly BSD. Patch by David Carlier.

bpo-14243 [https://bugs.python.org/issue?@action=redirect&bpo=14243]: The tempfile.NamedTemporaryFile function has a new optional parameter delete_on_close

bpo-41246 [https://bugs.python.org/issue?@action=redirect&bpo=41246]: Give the same callback function for when the overlapped operation is done to the functions recv, recv_into, recvfrom, sendto, send and sendfile inside IocpProactor.

bpo-39264 [https://bugs.python.org/issue?@action=redirect&bpo=39264]: Fixed collections.UserDict.get() to not call __missing__() when a value is not found. This matches the behavior of dict. Patch by Bar Harel.

bpo-38693 [https://bugs.python.org/issue?@action=redirect&bpo=38693]: importlib now uses f-strings internally instead of str.format.

bpo-38267 [https://bugs.python.org/issue?@action=redirect&bpo=38267]: Add timeout parameter to asyncio.loop.shutdown_default_executor(). The default value is None, which means the executor will be given an unlimited amount of time. When called from asyncio.Runner or asyncio.run(), the default timeout is 5 minutes.

bpo-34828 [https://bugs.python.org/issue?@action=redirect&bpo=34828]: sqlite3.Connection.iterdump() now handles databases that use AUTOINCREMENT in one or more tables.

bpo-32990 [https://bugs.python.org/issue?@action=redirect&bpo=32990]: Support reading wave files with the WAVE_FORMAT_EXTENSIBLE format in the wave module.

bpo-26253 [https://bugs.python.org/issue?@action=redirect&bpo=26253]: Allow adjustable compression level for tarfile streams in tarfile.open().

Documentation

gh-85525 [https://github.com/python/cpython/issues/85525]: Remove extra row

gh-86404 [https://github.com/python/cpython/issues/86404]: Deprecated tools make suspicious and rstlint.py are now removed. They have been replaced by sphinx-lint [https://pypi.org/project/sphinx-lint/].

gh-97741 [https://github.com/python/cpython/issues/97741]: Fix ! in c domain ref target syntax via a conf.py patch, so it works as intended to disable ref target resolution.

gh-96432 [https://github.com/python/cpython/issues/96432]: Fraction literals now support whitespace around the forward slash, Fraction('2 / 3').

gh-96098 [https://github.com/python/cpython/issues/96098]: Improve discoverability of the higher level concurrent.futures module by providing clearer links from the lower level threading and multiprocessing modules.

gh-95957 [https://github.com/python/cpython/issues/95957]: What’s New 3.11 now has instructions for how to provide compiler and linker flags for Tcl/Tk and OpenSSL on RHEL 7 and CentOS 7.

gh-95588 [https://github.com/python/cpython/issues/95588]: Clarified the conflicting advice given in the ast documentation about ast.literal_eval() being “safe” for use on untrusted input while at the same time warning that it can crash the process. The latter statement is true and is deemed unfixable without a large amount of work unsuitable for a bugfix. So we keep the warning and no longer claim that literal_eval is safe.

gh-91207 [https://github.com/python/cpython/issues/91207]: Fix stylesheet not working in Windows CHM htmlhelp docs and add warning that they are deprecated. Contributed by C.A.M. Gerlach.

gh-95454 [https://github.com/python/cpython/issues/95454]: Replaced incorrectly written true/false values in documentation. Patch by Robert O’Shea

gh-95451 [https://github.com/python/cpython/issues/95451]: Update library documentation with availability information on WebAssembly platforms wasm32-emscripten and wasm32-wasi.

gh-95415 [https://github.com/python/cpython/issues/95415]: Use consistent syntax for platform availability. The directive now supports a content body and emits a warning when it encounters an unknown platform.

gh-94321 [https://github.com/python/cpython/issues/94321]: Document the PEP 246 [https://peps.python.org/pep-0246/] style protocol type sqlite3.PrepareProtocol.

gh-86128 [https://github.com/python/cpython/issues/86128]: Document a limitation in ThreadPoolExecutor where its exit handler is executed before any handlers in atexit.

gh-61162 [https://github.com/python/cpython/issues/61162]: Clarify sqlite3 behavior when How to use the connection context manager.

gh-87260 [https://github.com/python/cpython/issues/87260]: Align sqlite3 argument specs with the actual implementation.

gh-86986 [https://github.com/python/cpython/issues/86986]: The minimum Sphinx version required to build the documentation is now 3.2.

gh-88831 [https://github.com/python/cpython/issues/88831]: Augmented documentation of asyncio.create_task(). Clarified the need to keep strong references to tasks and added a code snippet detailing how to do this.

gh-86438 [https://github.com/python/cpython/issues/86438]: Clarify that -W and PYTHONWARNINGS are matched literally and case-insensitively, rather than as regular expressions, in warnings.

gh-93031 [https://github.com/python/cpython/issues/93031]: Update tutorial introduction output to use 3.10+ SyntaxError invalid range.

gh-92240 [https://github.com/python/cpython/issues/92240]: Added release dates for “What’s New in Python 3.X” for 3.0, 3.1, 3.2, 3.8 and 3.10

bpo-47161 [https://bugs.python.org/issue?@action=redirect&bpo=47161]: Document that pathlib.PurePath does not collapse initial double slashes because they denote UNC paths.

bpo-40838 [https://bugs.python.org/issue?@action=redirect&bpo=40838]: Document that inspect.getdoc(), inspect.getmodule(), and inspect.getsourcefile() might return None.

bpo-43689 [https://bugs.python.org/issue?@action=redirect&bpo=43689]: The Differ documentation now also mentions other whitespace characters, which make it harder to understand the diff output.

bpo-38056 [https://bugs.python.org/issue?@action=redirect&bpo=38056]: Overhaul the 에러 처리기 documentation in codecs.

bpo-13553 [https://bugs.python.org/issue?@action=redirect&bpo=13553]: Document tkinter.Tk args.

Tests

gh-95027 [https://github.com/python/cpython/issues/95027]: On Windows, when the Python test suite is run with the -jN option, the ANSI code page is now used as the encoding for the stdout temporary file, rather than using UTF-8 which can lead to decoding errors. Patch by Victor Stinner.

gh-96624 [https://github.com/python/cpython/issues/96624]: Fixed the failure of repeated runs of test.test_unittest caused by side effects in test_dotted_but_module_not_loaded.

gh-95243 [https://github.com/python/cpython/issues/95243]: Mitigate the inherent race condition from using find_unused_port() in testSockName() by trying to find an unused port a few times before failing. Patch by Ross Burton.

gh-95573 [https://github.com/python/cpython/issues/95573]: Lib/test/test_asyncio/test_ssl.py [https://github.com/python/cpython/tree/main/Lib/test/test_asyncio/test_ssl.py] exposed a bug in the macOS kernel where intense concurrent load on non-blocking sockets occasionally causes errno.ENOBUFS (“No buffer space available”) to be emitted. FB11063974 filed with Apple, in the mean time as a workaround buffer size used in tests on macOS is decreased to avoid intermittent failures. Patch by Fantix King.

gh-95280 [https://github.com/python/cpython/issues/95280]: Fix problem with test_ssl test_get_ciphers on systems that require perfect forward secrecy (PFS) ciphers.

gh-95212 [https://github.com/python/cpython/issues/95212]: Make multiprocessing test case test_shared_memory_recreate parallel-safe.

gh-95218 [https://github.com/python/cpython/issues/95218]: Move tests for importlib.resources into test_importlib.resources.

gh-93963 [https://github.com/python/cpython/issues/93963]: Updated tests to use preferred location for importlib.resources ABCs.

gh-94675 [https://github.com/python/cpython/issues/94675]: Add a regression test for re exponentional slowdown when using rjsmin.

gh-91330 [https://github.com/python/cpython/issues/91330]: Added more tests for dataclasses to cover behavior with data descriptor-based fields.

gh-94208 [https://github.com/python/cpython/issues/94208]: test_ssl is now checking for supported TLS version and protocols in more tests.

gh-94315 [https://github.com/python/cpython/issues/94315]: Tests now check for DAC override capability instead of relying on os.geteuid().

gh-54781 [https://github.com/python/cpython/issues/54781]: Rename test_tk to test_tkinter, and rename test_ttk_guionly to test_ttk. Patch by Victor Stinner.

gh-93839 [https://github.com/python/cpython/issues/93839]: Move Lib/ctypes/test/ to Lib/test/test_ctypes/. Patch by Victor Stinner.

gh-93951 [https://github.com/python/cpython/issues/93951]: In test_bdb.StateTestCase.test_skip, avoid including auxiliary importers.

gh-93957 [https://github.com/python/cpython/issues/93957]: Provide nicer error reporting from subprocesses in test_venv.EnsurePipTest.test_with_pip.

gh-93884 [https://github.com/python/cpython/issues/93884]: Add test cases for PyNumber_ToBase() that take a large number or a non-int object as parameter.

gh-93852 [https://github.com/python/cpython/issues/93852]: test_asyncio, test_logging, test_socket and test_socketserver now create AF_UNIX domains in the current directory to no longer fail with OSError("AF_UNIX path too long") if the temporary directory (the TMPDIR environment variable) is too long. Patch by Victor Stinner.

gh-93353 [https://github.com/python/cpython/issues/93353]: regrtest now checks if a test leaks temporary files or directories if run with -jN option. Patch by Victor Stinner.

gh-84461 [https://github.com/python/cpython/issues/84461]: run_tests.py now handles cross compiling env vars correctly and pass HOSTRUNNER to regression tests.

gh-93616 [https://github.com/python/cpython/issues/93616]: test_modulefinder now creates a temporary directory in ModuleFinderTest.setUp() instead of module scope.

gh-93575 [https://github.com/python/cpython/issues/93575]: Fix issue with test_unicode test_raiseMemError. The test case now use test.support.calcobjsize to calculate size of PyUnicode structs. sys.getsizeof() may return different size when string has UTF-8 memory.

gh-90473 [https://github.com/python/cpython/issues/90473]: WASI does not have a chmod(2) syscall. os.chmod() is now a dummy function on WASI. Skip all tests that depend on working os.chmod().

gh-90473 [https://github.com/python/cpython/issues/90473]: Skip tests on WASI that require symlinks with absolute paths.

gh-57539 [https://github.com/python/cpython/issues/57539]: Increase calendar test coverage for calendar.LocaleTextCalendar.formatweekday().

gh-90473 [https://github.com/python/cpython/issues/90473]: Skip symlink tests on WASI. wasmtime uses openat2(2) with RESOLVE_BENEATH flag, which prevents symlinks with absolute paths.

gh-89858 [https://github.com/python/cpython/issues/89858]: Fix test_embed for out-of-tree builds. Patch by Kumar Aditya.

gh-92886 [https://github.com/python/cpython/issues/92886]: Fixing tests that fail when running with optimizations (-O) in test_imaplib.py.

gh-92886 [https://github.com/python/cpython/issues/92886]: Fixing tests that fail when running with optimizations (-O) in test_zipimport.py

gh-92886 [https://github.com/python/cpython/issues/92886]: Fixing tests that fail when running with optimizations (-O) in test_py_compile.py

gh-92886 [https://github.com/python/cpython/issues/92886]: Fixing tests that fail when running with optimizations (-O) in test_sys_settrace.py.

gh-92886 [https://github.com/python/cpython/issues/92886]: Fixing tests that fail when running with optimizations (-O) in _test_multiprocessing.py

gh-92670 [https://github.com/python/cpython/issues/92670]: Skip test_shutil.TestCopy.test_copyfile_nonexistent_dir test on AIX as the test uses a trailing slash to force the OS consider the path as a directory, but on AIX the trailing slash has no effect and is considered as a file.

gh-92514 [https://github.com/python/cpython/issues/92514]: Remove unused test.support.BasicTestRunner. Patch by Jelle Zijlstra.

bpo-47016 [https://bugs.python.org/issue?@action=redirect&bpo=47016]: Create a GitHub Actions workflow for verifying bundled pip and setuptools. Patch by Illia Volochii and Adam Turner.

Build

gh-96761 [https://github.com/python/cpython/issues/96761]: Fix the build process of clang compiler for _bootstrap_python if LTO optimization is applied. Patch by Matthias Görgens and Donghee Na.

gh-96883 [https://github.com/python/cpython/issues/96883]: wasm32-emscripten builds for browsers now include concurrent.futures for asyncio and unittest.mock.

gh-85936 [https://github.com/python/cpython/issues/85936]: CPython now uses the ThinLTO option as the default policy if the Clang compiler accepts the flag. Patch by Donghee Na.

gh-96729 [https://github.com/python/cpython/issues/96729]: Ensure that Windows releases built with Tools\msi\buildrelease.bat are upgradable to and from official Python releases.

gh-96269 [https://github.com/python/cpython/issues/96269]: Shared module targets now depend on new MODULE_DEPS variable, which includes EXPORTSYMS. This fixes a build order issue on unsupported AIX platform.

gh-84461 [https://github.com/python/cpython/issues/84461]: wasm32-emscripten platform no longer builds resource module, getresuid(), getresgid(), and their setters. The APIs are stubs and not functional.

gh-95973 [https://github.com/python/cpython/issues/95973]: Add a new --with-dsymutil configure option to link debug information in macOS. Patch by Pablo Galindo.

gh-90536 [https://github.com/python/cpython/issues/90536]: Use the BOLT post-link optimizer to improve performance, particularly on medium-to-large applications.

gh-93744 [https://github.com/python/cpython/issues/93744]: Remove the configure --with-cxx-main build option: it didn’t work for many years. Remove the MAINCC variable from configure and Makefile. Patch by Victor Stinner.

gh-94801 [https://github.com/python/cpython/issues/94801]: Fix a regression in configure script that caused some header checks to ignore custom CPPFLAGS. The regression was introduced in gh-94802 [https://github.com/python/cpython/issues/94802].

gh-95145 [https://github.com/python/cpython/issues/95145]: wasm32-wasi builds no longer depend on WASIX’s pthread stubs. Python now has its own stubbed pthread API.

gh-95174 [https://github.com/python/cpython/issues/95174]: Python now detects missing dup function in WASI and works around some missing errno, select, and socket constants.

gh-95174 [https://github.com/python/cpython/issues/95174]: Python now skips missing socket functions and methods on WASI. WASI can only create sockets from existing fd / accept and has no netdb.

gh-95085 [https://github.com/python/cpython/issues/95085]: Platforms wasm32-unknown-emscripten and wasm32-unknown-wasi have been promoted to PEP 11 [https://peps.python.org/pep-0011/] tier 3 platform support.

gh-94847 [https://github.com/python/cpython/issues/94847]: Fixed _decimal module build issue on GCC when compiling with LTO and pydebug. Debug builds no longer force inlining of functions.

gh-94841 [https://github.com/python/cpython/issues/94841]: Fix the possible performance regression of PyObject_Free() compiled with MSVC version 1932.

gh-94801 [https://github.com/python/cpython/issues/94801]: configure now uses custom flags like ZLIB_CFLAGS and ZLIB_LIBS when searching for headers and libraries.

gh-94773 [https://github.com/python/cpython/issues/94773]: deepfreeze.py now supports code object with frozensets that contain incompatible, unsortable types.

gh-94682 [https://github.com/python/cpython/issues/94682]: Build and test with OpenSSL 1.1.1q

gh-90005 [https://github.com/python/cpython/issues/90005]: Dependencies of readline and curses module are now detected in configure script with pkg-config. Only ncurses / ncursesw are detected automatically. The old curses library is not configured automatically. Workaround for missing termcap or tinfo library has been removed.

gh-90005 [https://github.com/python/cpython/issues/90005]: Fix building _ctypes extension without pkg-config.

gh-90005 [https://github.com/python/cpython/issues/90005]: _dbm module dependencies are now detected by configure.

gh-94404 [https://github.com/python/cpython/issues/94404]: makesetup now works around an issue with sed on macOS and uses correct CFLAGS for object files that end up in a shared extension. Module CFLAGS are used before PY_STDMODULE_CFLAGS to avoid clashes with system headers.

gh-93939 [https://github.com/python/cpython/issues/93939]: C extension modules are now built by configure and make instead of distutils and setup.py.

gh-93939 [https://github.com/python/cpython/issues/93939]: The 2to3, idle, and pydoc scripts are now generated and installed by Makefile instead of setup.py.

gh-94280 [https://github.com/python/cpython/issues/94280]: Updated pegen regeneration script on Windows to find and use Python 3.9 or higher. Prior to this, pegen regeneration already required 3.9 or higher, but the script may have used lower versions of Python.

gh-93584 [https://github.com/python/cpython/issues/93584]: Address race condition in Makefile when installing a PGO build. All test and install targets now depend on all target.

gh-93491 [https://github.com/python/cpython/issues/93491]: configure now detects and reports PEP 11 [https://peps.python.org/pep-0011/] support tiers.

gh-69093 [https://github.com/python/cpython/issues/69093]: Fix Modules/Setup.stdlib.in rule for _sqlite3 extension.

gh-93207 [https://github.com/python/cpython/issues/93207]: va_start() with two parameters, like va_start(args, format), is now required to build Python. va_start() is no longer called with a single parameter. Patch by Kumar Aditya.

gh-93202 [https://github.com/python/cpython/issues/93202]: Python now always use the %zu and %zd printf formats to format a size_t or Py_ssize_t number. Building Python 3.12 requires a C11 compiler, so these printf formats are now always supported. Patch by Victor Stinner.

gh-90473 [https://github.com/python/cpython/issues/90473]: Disable pymalloc and increase stack size on wasm32-wasi.

bpo-34449 [https://bugs.python.org/issue?@action=redirect&bpo=34449]: Drop invalid compiler switch -fPIC for HP aCC on HP-UX. Patch by Michael Osipov.

Windows

gh-98360 [https://github.com/python/cpython/issues/98360]: Fixes multiprocessing spawning child processes on Windows from a virtual environment to ensure that child processes that also use multiprocessing to spawn more children will recognize that they are in a virtual environment.

gh-98414 [https://github.com/python/cpython/issues/98414]: Fix py.exe launcher handling of -V:<company>/ option when default preferences have been set in environment variables or configuration files.

gh-97728 [https://github.com/python/cpython/issues/97728]: Fix possible crashes caused by the use of uninitialized variables when pass invalid arguments in os.system() on Windows and in Windows-specific modules (like winreg).

gh-90989 [https://github.com/python/cpython/issues/90989]: Made 윈도우 용 파이썬 런처 install per-user by default (unless an all users install already exists), and clarify some text in the installer.

gh-97649 [https://github.com/python/cpython/issues/97649]: The Tools directory is no longer installed on Windows

gh-96965 [https://github.com/python/cpython/issues/96965]: Update libffi to 3.4.3

gh-96577 [https://github.com/python/cpython/issues/96577]: Fixes a potential buffer overrun in msilib.

gh-96559 [https://github.com/python/cpython/issues/96559]: Fixes the Windows launcher not using the compatible interpretation of default tags found in configuration files when no tag was passed to the command.

gh-94781 [https://github.com/python/cpython/issues/94781]: Fix pcbuild.proj to clean previous instances of output files in Python\deepfreeze and Python\frozen_modules directories on Windows. Patch by Charlie Zhao.

gh-89545 [https://github.com/python/cpython/issues/89545]: Updates platform code getting the Windows version to use native Windows Management Instrumentation (WMI) queries to determine OS version, type, and architecture.

gh-95733 [https://github.com/python/cpython/issues/95733]: Make certain requirements of the Windows Store package optional to allow installing on earlier updates of Windows.

gh-95656 [https://github.com/python/cpython/issues/95656]: Enable the enable_load_extension() sqlite3 API.

gh-95587 [https://github.com/python/cpython/issues/95587]: Fixes some issues where the Windows installer would incorrectly detect certain features of an existing install when upgrading.

gh-94399 [https://github.com/python/cpython/issues/94399]: Restores the behaviour of 윈도우 용 파이썬 런처 for /usr/bin/env shebang lines, which will now search PATH for an executable matching the given command. If none is found, the usual search process is used.

gh-95445 [https://github.com/python/cpython/issues/95445]: Fixes the unsuccessful removal of the HTML document directory when uninstalling with Windows msi.

gh-95359 [https://github.com/python/cpython/issues/95359]: Fix 윈도우 용 파이썬 런처 handling of py.ini commands (it was incorrectly expecting a py_ prefix on keys) and crashes when reading per-user configuration file.

gh-95285 [https://github.com/python/cpython/issues/95285]: Fix 윈도우 용 파이썬 런처 handling of command lines where it is only passed a short executable name.

gh-90844 [https://github.com/python/cpython/issues/90844]: Allow virtual environments to correctly launch when they have spaces in the path.

gh-94772 [https://github.com/python/cpython/issues/94772]: Fix incorrect handling of shebang lines in py.exe launcher

gh-94018 [https://github.com/python/cpython/issues/94018]: zipfile will now remove trailing spaces from path components when extracting files on Windows.

gh-93824 [https://github.com/python/cpython/issues/93824]: Drag and drop of files onto Python files in Windows Explorer has been enabled for Windows ARM64.

gh-43414 [https://github.com/python/cpython/issues/43414]: os.get_terminal_size() now attempts to read the size from any provided handle, rather than only supporting file descriptors 0, 1 and 2.

gh-92817 [https://github.com/python/cpython/issues/92817]: Ensures that py.exe will prefer an active virtual environment over default tags specified with environment variables or through a py.ini file.

gh-92984 [https://github.com/python/cpython/issues/92984]: Explicitly disable incremental linking for non-Debug builds

gh-92841 [https://github.com/python/cpython/issues/92841]: asyncio no longer throws RuntimeError: Event loop is closed on interpreter exit after asynchronous socket activity. Patch by Oleg Iarygin.

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update Windows installer to use SQLite 3.38.4.

gh-91061 [https://github.com/python/cpython/issues/91061]: Accept os.PathLike for the argument to winsound.PlaySound

bpo-42658 [https://bugs.python.org/issue?@action=redirect&bpo=42658]: Support native Windows case-insensitive path comparisons by using LCMapStringEx instead of str.lower() in ntpath.normcase(). Add LCMapStringEx to the _winapi module.

bpo-38704 [https://bugs.python.org/issue?@action=redirect&bpo=38704]: Prevent installation on unsupported Windows versions.

macOS

gh-97897 [https://github.com/python/cpython/issues/97897]: The macOS 13 SDK includes support for the mkfifoat and mknodat system calls. Using the dir_fd option with either os.mkfifo() or os.mknod() could result in a segfault if cpython is built with the macOS 13 SDK but run on an earlier version of macOS. Prevent this by adding runtime support for detection of these system calls (“weaklinking”) as is done for other newer syscalls on macOS.

IDLE

gh-97527 [https://github.com/python/cpython/issues/97527]: Fix a bug in the previous bugfix that caused IDLE to not start when run with 3.10.8, 3.12.0a1, and at least Microsoft Python 3.10.2288.0 installed without the Lib/test package. 3.11.0 was never affected.

gh-65802 [https://github.com/python/cpython/issues/65802]: Document handling of extensions in Save As dialogs.

gh-95191 [https://github.com/python/cpython/issues/95191]: Include prompts when saving Shell (interactive input and output).

gh-95511 [https://github.com/python/cpython/issues/95511]: Fix the Shell context menu copy-with-prompts bug of copying an extra line when one selects whole lines.

gh-95471 [https://github.com/python/cpython/issues/95471]: In the Edit menu, move Select All and add a new separator.

gh-95411 [https://github.com/python/cpython/issues/95411]: Enable using IDLE’s module browser with .pyw files.

gh-89610 [https://github.com/python/cpython/issues/89610]: Add .pyi as a recognized extension for IDLE on macOS. This allows opening stub files by double clicking on them in the Finder.

Tools/Demos

gh-68686 [https://github.com/python/cpython/issues/68686]: Remove ptags and eptags scripts.

gh-97681 [https://github.com/python/cpython/issues/97681]: Remove the Tools/demo/ directory which contained old demo scripts. A copy can be found in the old-demos project [https://github.com/gvanrossum/old-demos]. Patch by Victor Stinner.

gh-97669 [https://github.com/python/cpython/issues/97669]: Remove outdated example scripts of the Tools/scripts/ directory. A copy can be found in the old-demos project [https://github.com/gvanrossum/old-demos]. Patch by Victor Stinner.

gh-95853 [https://github.com/python/cpython/issues/95853]: The wasm_build.py script now pre-builds Emscripten ports, checks for broken EMSDK versions, and warns about pkg-config env vars.

gh-95853 [https://github.com/python/cpython/issues/95853]: The new tool Tools/wasm/wasm_builder.py automates configure, compile, and test steps for building CPython on WebAssembly platforms.

gh-95731 [https://github.com/python/cpython/issues/95731]: Fix handling of module docstrings in Tools/i18n/pygettext.py.

gh-93939 [https://github.com/python/cpython/issues/93939]: Add script Tools/scripts/check_modules.py to check and validate builtin and shared extension modules. The script also handles Modules/Setup and will eventually replace setup.py.

gh-94538 [https://github.com/python/cpython/issues/94538]: Fix Argument Clinic output to custom file destinations. Patch by Erlend E. Aasland.

gh-94430 [https://github.com/python/cpython/issues/94430]: Allow parameters named module and self with custom C names in Argument Clinic. Patch by Erlend E. Aasland

gh-86087 [https://github.com/python/cpython/issues/86087]: The Tools/scripts/parseentities.py script used to parse HTML4 entities has been removed.

C API

gh-98393 [https://github.com/python/cpython/issues/98393]: The PyUnicode_FSDecoder() function no longer accepts bytes-like paths, like bytearray and memoryview types: only the exact bytes type is accepted for bytes strings. Patch by Victor Stinner.

gh-91051 [https://github.com/python/cpython/issues/91051]: Add PyType_Watch() and related APIs to allow callbacks on PyType_Modified().

gh-95756 [https://github.com/python/cpython/issues/95756]: Lazily create and cache co_ attributes for better performance for code getters.

gh-96512 [https://github.com/python/cpython/issues/96512]: Configuration for the integer string conversion length limitation now lives in the PyConfig C API struct.

gh-95589 [https://github.com/python/cpython/issues/95589]: Extensions classes that set tp_dictoffset and tp_weaklistoffset lose the support for multiple inheritance, but are now safe. Extension classes should use Py_TPFLAGS_MANAGED_DICT and Py_TPFLAGS_MANAGED_WEAKREF instead.

gh-95781 [https://github.com/python/cpython/issues/95781]: An unrecognized format character in PyUnicode_FromFormat() and PyUnicode_FromFormatV() now sets a SystemError. In previous versions it caused all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded.

gh-92678 [https://github.com/python/cpython/issues/92678]: Restore the 3.10 behavior for multiple inheritance of C extension classes that store their dictionary at the end of the struct.

gh-92678 [https://github.com/python/cpython/issues/92678]: Support C extensions using managed dictionaries by setting the Py_TPFLAGS_MANAGED_DICT flag.

gh-93274 [https://github.com/python/cpython/issues/93274]: API for implementing vectorcall (Py_TPFLAGS_HAVE_VECTORCALL, PyVectorcall_NARGS() and PyVectorcall_Call()) was added to the limited API and stable ABI.

gh-95504 [https://github.com/python/cpython/issues/95504]: Fix sign placement when specifying width or precision in PyUnicode_FromFormat() and PyUnicode_FromFormatV(). Patch by Philip Georgi.

gh-93012 [https://github.com/python/cpython/issues/93012]: The Py_TPFLAGS_HAVE_VECTORCALL flag is now removed from a class when the class’s __call__() method is reassigned. This makes vectorcall safe to use with mutable types (i.e. heap types without the immutable flag). Mutable types that do not override tp_call now inherit the Py_TPFLAGS_HAVE_VECTORCALL flag.

gh-95388 [https://github.com/python/cpython/issues/95388]: Creating immutable types with mutable bases is deprecated and is planned to be disabled in Python 3.14.

gh-92678 [https://github.com/python/cpython/issues/92678]: Adds unstable C-API functions _PyObject_VisitManagedDict and _PyObject_ClearManagedDict to allow C extensions to allow the VM to manage their object’s dictionaries.

gh-94936 [https://github.com/python/cpython/issues/94936]: Added PyCode_GetVarnames(), PyCode_GetCellvars() and PyCode_GetFreevars() for accessing co_varnames, co_cellvars and co_freevars respectively via the C API.

gh-94930 [https://github.com/python/cpython/issues/94930]: Fix SystemError raised when PyArg_ParseTupleAndKeywords() is used with # in (...) but without PY_SSIZE_T_CLEAN defined.

gh-94731 [https://github.com/python/cpython/issues/94731]: Python again uses C-style casts for most casting operations when compiled with C++. This may trigger compiler warnings, if they are enabled with e.g. -Wold-style-cast or -Wzero-as-null-pointer-constant options for g++.

gh-93937 [https://github.com/python/cpython/issues/93937]: The following frame functions and type are now directly available with #include <Python.h>, it’s no longer needed to add #include <frameobject.h>:

PyFrame_Check()

PyFrame_GetBack()

PyFrame_GetBuiltins()

PyFrame_GetGenerator()

PyFrame_GetGlobals()

PyFrame_GetLasti()

PyFrame_GetLocals()

PyFrame_Type

Patch by Victor Stinner.

gh-91321 [https://github.com/python/cpython/issues/91321]: Fix the compatibility of the Python C API with C++ older than C++11. Patch by Victor Stinner.

gh-91731 [https://github.com/python/cpython/issues/91731]: Avoid defining the static_assert when compiling with C++ 11, where this is a keyword and redefining it can lead to undefined behavior. Patch by Pablo Galindo

gh-89546 [https://github.com/python/cpython/issues/89546]: PyType_FromMetaclass() (and other PyType_From* functions) now check that offsets and the base class’s tp_basicsize fit in the new class’s tp_basicsize.

gh-93503 [https://github.com/python/cpython/issues/93503]: Add two new public functions to the public C-API, PyEval_SetProfileAllThreads() and PyEval_SetTraceAllThreads(), that allow to set tracing and profiling functions in all running threads in addition to the calling one. Also, two analogous functions to the threading module (threading.setprofile_all_threads() and threading.settrace_all_threads()) that allow to do the same from Python. Patch by Pablo Galindo

gh-93442 [https://github.com/python/cpython/issues/93442]: Add C++ overloads for _Py_CAST_impl() to handle 0/NULL. This will allow C++ extensions that pass 0 or NULL to macros using _Py_CAST() to continue to compile.

gh-93466 [https://github.com/python/cpython/issues/93466]: Slot IDs in PyType_Spec may not be repeated. The documentation was updated to mention this. For some cases of repeated slots, PyType_FromSpec and related functions will now raise an exception.

gh-92898 [https://github.com/python/cpython/issues/92898]: Fix C++ compiler warnings when casting function arguments to PyObject*. Patch by Serge Guelton.

gh-93103 [https://github.com/python/cpython/issues/93103]: Deprecate global configuration variables, like Py_IgnoreEnvironmentFlag, in the documentation: the Py_InitializeFromConfig() API should be instead. Patch by Victor Stinner.

gh-77782 [https://github.com/python/cpython/issues/77782]: Deprecate global configuration variable like Py_IgnoreEnvironmentFlag: the Py_InitializeFromConfig() API should be instead. Patch by Victor Stinner.

gh-92913 [https://github.com/python/cpython/issues/92913]: Ensures changes to PyConfig.module_search_paths are ignored unless PyConfig.module_search_paths_set is set

gh-92781 [https://github.com/python/cpython/issues/92781]: Avoid mixing declarations and code in the C API to fix the compiler warning: “ISO C90 forbids mixed declarations and code” [-Werror=declaration-after-statement]. Patch by Victor Stinner.

gh-92651 [https://github.com/python/cpython/issues/92651]: Remove the token.h header file. There was never any public tokenizer C API. The token.h header file was only designed to be used by Python internals. Patch by Victor Stinner.

gh-92536 [https://github.com/python/cpython/issues/92536]: Remove legacy Unicode APIs based on Py_UNICODE*.

gh-85858 [https://github.com/python/cpython/issues/85858]: Remove the PyUnicode_InternImmortal() function and the SSTATE_INTERNED_IMMORTAL macro. Patch by Victor Stinner.

gh-92193 [https://github.com/python/cpython/issues/92193]: Add new function PyFunction_SetVectorcall() to the C API which sets the vectorcall field of a given PyFunctionObject.

Warning: extensions using this API must preserve the behavior of the unaltered function!

gh-59121 [https://github.com/python/cpython/issues/59121]: Fixed an assert that prevented PyRun_InteractiveOne from providing tracebacks when parsing from the provided FD.

bpo-45383 [https://bugs.python.org/issue?@action=redirect&bpo=45383]: The PyType_FromSpec() API will now find and use a metaclass based on the provided bases. An error will be raised if there is a metaclass conflict.

Python 3.11.0 beta 1

Release date: 2022-05-06

Security

gh-57684 [https://github.com/python/cpython/issues/57684]: Add the -P command line option and the PYTHONSAFEPATH environment variable to not prepend a potentially unsafe path to sys.path. Patch by Victor Stinner.

Core and Builtins

gh-89519 [https://github.com/python/cpython/issues/89519]: Chaining classmethod descriptors (introduced in bpo-19072 [https://bugs.python.org/issue?@action=redirect&bpo=19072]) is deprecated. It can no longer be used to wrap other descriptors such as property(). The core design of this feature was flawed, and it caused a number of downstream problems.

gh-92345 [https://github.com/python/cpython/issues/92345]: pymain_run_python() now imports readline and rlcompleter before sys.path is extended to include the current working directory of an interactive interpreter. Non-interactive interpreters are not affected.

bpo-43857 [https://bugs.python.org/issue?@action=redirect&bpo=43857]: Improve the AttributeError message when deleting a missing attribute. Patch by Géry Ogam.

gh-92245 [https://github.com/python/cpython/issues/92245]: Make sure that PEP 523 is respected in all cases. In 3.11a7, specialization may have prevented Python-to-Python calls respecting PEP 523.

gh-92203 [https://github.com/python/cpython/issues/92203]: Add a closure keyword-only parameter to exec(). It can only be specified when exec-ing a code object that uses free variables. When specified, it must be a tuple, with exactly the number of cell variables referenced by the code object. closure has a default value of None, and it must be None if the code object doesn’t refer to any free variables.

gh-91173 [https://github.com/python/cpython/issues/91173]: Disable frozen modules in debug builds. Patch by Kumar Aditya.

gh-92114 [https://github.com/python/cpython/issues/92114]: Improve error message when subscript a type with __class_getitem__ set to None.

gh-92112 [https://github.com/python/cpython/issues/92112]: Fix crash triggered by an evil custom mro() on a metaclass.

gh-92063 [https://github.com/python/cpython/issues/92063]: The PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS instruction now ensures methods are called only on objects of the correct type.

gh-92031 [https://github.com/python/cpython/issues/92031]: Deoptimize statically allocated code objects during Py_FINALIZE() so that future _PyCode_Quicken calls always start with unquickened code.

gh-92036 [https://github.com/python/cpython/issues/92036]: Fix a crash in subinterpreters related to the garbage collector. When a subinterpreter is deleted, untrack all objects tracked by its GC. To prevent a crash in deallocator functions expecting objects to be tracked by the GC, leak a strong reference to these objects on purpose, so they are never deleted and their deallocator functions are not called. Patch by Victor Stinner.

gh-92032 [https://github.com/python/cpython/issues/92032]: The interpreter can now autocomplete soft keywords, as of now match, case, and _ (wildcard pattern) from PEP 634 [https://peps.python.org/pep-0634/].

gh-87999 [https://github.com/python/cpython/issues/87999]: The warning emitted by the Python parser for a numeric literal immediately followed by keyword has been changed from deprecation warning to syntax warning.

gh-91869 [https://github.com/python/cpython/issues/91869]: Fix an issue where specialized opcodes with extended arguments could produce incorrect tracing output or lead to assertion failures.

gh-91603 [https://github.com/python/cpython/issues/91603]: Speed up types.UnionType instantiation. Based on patch provided by Yurii Karabas.

gh-89373 [https://github.com/python/cpython/issues/89373]: If Python is built in debug mode, Python now ensures that deallocator functions leave the current exception unchanged. Patch by Victor Stinner.

gh-91632 [https://github.com/python/cpython/issues/91632]: Fix a minor memory leak at exit: release the memory of the generic_alias_iterator type. Patch by Donghee Na.

gh-81548 [https://github.com/python/cpython/issues/81548]: Octal escapes with value larger than 0o377 now produce a DeprecationWarning. In a future Python version they will be a SyntaxWarning and eventually a SyntaxError.

bpo-43950 [https://bugs.python.org/issue?@action=redirect&bpo=43950]: Use a single compact table for line starts, ends and column offsets. Reduces memory consumption for location info by half

gh-91102 [https://github.com/python/cpython/issues/91102]: Use Argument Clinic for EncodingMap. Patch by Oleg Iarygin.

gh-91636 [https://github.com/python/cpython/issues/91636]: Fixed a crash in a garbage-collection edge-case, in which a PyFunction_Type.tp_clear function could leave a python function object in an inconsistent state.

gh-91603 [https://github.com/python/cpython/issues/91603]: Speed up isinstance() and issubclass() checks for types.UnionType. Patch by Yurii Karabas.

gh-91625 [https://github.com/python/cpython/issues/91625]: Fixed a bug in which adaptive opcodes ignored any preceding EXTENDED_ARGs on specialization failure.

gh-78607 [https://github.com/python/cpython/issues/78607]: The LLTRACE special build now looks for the name __lltrace__ defined in module globals, rather than the name __ltrace__, which had been introduced as a typo.

gh-91576 [https://github.com/python/cpython/issues/91576]: Speed up iteration of ascii strings by 50%. Patch by Kumar Aditya.

gh-89279 [https://github.com/python/cpython/issues/89279]: Improve interpreter performance on Windows by inlining a few specific macros.

gh-91502 [https://github.com/python/cpython/issues/91502]: Add a new _PyFrame_IsEntryFrame() API function, to check if a PyFrameObject is an entry frame. Patch by Pablo Galindo.

gh-91266 [https://github.com/python/cpython/issues/91266]: Refactor the bytearray strip methods strip, lstrip and rstrip to use a common implementation.

gh-91479 [https://github.com/python/cpython/issues/91479]: Replaced the __note__ field of BaseException (added in an earlier version of 3.11) with the final design of PEP 678 [https://peps.python.org/pep-0678/]. Namely, BaseException gets an add_note() method, and its __notes__ field is created when necessary.

gh-46055 [https://github.com/python/cpython/issues/46055]: Speed up right shift of negative integers, by removing unnecessary creation of temporaries. Original patch by Xinhang Xu, reworked by Mark Dickinson.

gh-91462 [https://github.com/python/cpython/issues/91462]: Make the interpreter’s low-level tracing (lltrace) feature output more readable by displaying opcode names (rather than just numbers), and by displaying stack contents before each opcode.

gh-89455 [https://github.com/python/cpython/issues/89455]: Fixed an uninitialized bool value in the traceback printing code path that was introduced by the initial bpo-45292 [https://bugs.python.org/issue?@action=redirect&bpo=45292] exception groups work.

gh-91421 [https://github.com/python/cpython/issues/91421]: Fix a potential integer overflow in _Py_DecodeUTF8Ex.

gh-91428 [https://github.com/python/cpython/issues/91428]: Add static const char *const _PyOpcode_OpName[256] = {...}; to opcode.h for debug builds to assist in debugging the Python interpreter. It is now more convenient to make various forms of debugging output more human-readable by including opcode names rather than just the corresponding decimal digits.

bpo-47120 [https://bugs.python.org/issue?@action=redirect&bpo=47120]: Make POP_JUMP_IF_TRUE, POP_JUMP_IF_FALSE, POP_JUMP_IF_NONE and POP_JUMP_IF_NOT_NONE virtual, mapping to new relative jump opcodes.

bpo-45317 [https://bugs.python.org/issue?@action=redirect&bpo=45317]: Add internal documentation explaining design of new (for 3.11) frame stack.

bpo-47197 [https://bugs.python.org/issue?@action=redirect&bpo=47197]: ctypes used to mishandle void return types, so that for instance a function declared like ctypes.CFUNCTYPE(None, ctypes.c_int) would be called with signature int f(int) instead of void f(int). Wasm targets require function pointers to be called with the correct signatures so this led to crashes. The problem is now fixed.

bpo-47120 [https://bugs.python.org/issue?@action=redirect&bpo=47120]: Make opcodes JUMP_IF_TRUE_OR_POP and JUMP_IF_FALSE_OR_POP relative rather than absolute.

bpo-47177 [https://bugs.python.org/issue?@action=redirect&bpo=47177]: Replace the f_lasti member of the internal _PyInterpreterFrame structure with a prev_instr pointer, which reduces overhead in the main interpreter loop. The f_lasti attribute of Python-layer frame objects is preserved for backward-compatibility.

bpo-46961 [https://bugs.python.org/issue?@action=redirect&bpo=46961]: Integer mod/remainder operations, including the three-argument form of pow(), now consistently return ints from the global small integer cache when applicable.

bpo-46962 [https://bugs.python.org/issue?@action=redirect&bpo=46962]: Classes and functions that unconditionally declared their docstrings ignoring the --without-doc-strings compilation flag no longer do so.

The classes affected are ctypes.UnionType, pickle.PickleBuffer, testcapi.RecursingInfinitelyError, and types.GenericAlias.

The functions affected are 24 methods in ctypes.

Patch by Oleg Iarygin.

bpo-46942 [https://bugs.python.org/issue?@action=redirect&bpo=46942]: Use Argument Clinic for the types.MethodType constructor. Patch by Oleg Iarygin.

bpo-46764 [https://bugs.python.org/issue?@action=redirect&bpo=46764]: Fix wrapping bound methods with @classmethod

bpo-43464 [https://bugs.python.org/issue?@action=redirect&bpo=43464]: Optimize set.intersection() for non-set arguments.

bpo-46721 [https://bugs.python.org/issue?@action=redirect&bpo=46721]: Optimize set.issuperset() for non-set argument.

bpo-46509 [https://bugs.python.org/issue?@action=redirect&bpo=46509]: Add type-specialized versions of the Py_DECREF(), and use them for float, int, str, bool, and None to avoid pointer-chasing at runtime where types are known at C compile time.

bpo-46045 [https://bugs.python.org/issue?@action=redirect&bpo=46045]: Do not use POSIX semaphores on NetBSD

bpo-36819 [https://bugs.python.org/issue?@action=redirect&bpo=36819]: Fix crashes in built-in encoders with error handlers that return position less or equal than the starting position of non-encodable characters.

bpo-34093 [https://bugs.python.org/issue?@action=redirect&bpo=34093]: marshal.dumps() uses FLAG_REF for all interned strings. This makes output more deterministic and helps reproducible build.

bpo-26579 [https://bugs.python.org/issue?@action=redirect&bpo=26579]: Added object.__getstate__ which provides the default implementation of the __getstate__() method.

Copying and pickling instances of subclasses of builtin types bytearray, set, frozenset, collections.OrderedDict, collections.deque, weakref.WeakSet, and datetime.tzinfo now copies and pickles instance attributes implemented as slots.

Library

gh-87901 [https://github.com/python/cpython/issues/87901]: Add the encoding parameter to os.popen().

gh-90997 [https://github.com/python/cpython/issues/90997]: Fix an issue where dis utilities may interpret populated inline cache entries as valid instructions.

gh-92332 [https://github.com/python/cpython/issues/92332]: Deprecate typing.Text (removal of the class is currently not planned). Patch by Alex Waygood.

Deprecate nested classes in enum definitions becoming members – in 3.13 they will be normal classes; add member and nonmember functions to allow control over results now.

gh-92356 [https://github.com/python/cpython/issues/92356]: Fixed a performance regression in ctypes function calls.

gh-90997 [https://github.com/python/cpython/issues/90997]: Show the actual named values stored in inline caches when show_caches=True is passed to dis utilities.

gh-92301 [https://github.com/python/cpython/issues/92301]: Prefer close_range() to iterating over procfs for file descriptor closing in subprocess for better performance.

gh-67248 [https://github.com/python/cpython/issues/67248]: Sort the miscellaneous topics in Cmd.do_help()

gh-92210 [https://github.com/python/cpython/issues/92210]: Port socket.__init__ to Argument Clinic. Patch by Cinder.

gh-80010 [https://github.com/python/cpython/issues/80010]: Add support for generalized ISO 8601 parsing to datetime.datetime.fromisoformat(), datetime.date.fromisoformat() and datetime.time.fromisoformat(). Patch by Paul Ganssle.

gh-92118 [https://github.com/python/cpython/issues/92118]: Fix a 3.11 regression in contextmanager(), which caused it to propagate exceptions with incorrect tracebacks.

gh-90887 [https://github.com/python/cpython/issues/90887]: Adding COPYFILE_STAT, COPYFILE_ACL and COPYFILE_XATTR constants for os.fcopyfile() available in macOs.

gh-91215 [https://github.com/python/cpython/issues/91215]: For @dataclass, add weakref_slot. The new parameter defaults to False. If true, and if slots=True, add a slot named "__weakref__", which will allow instances to be weakref’d. Contributed by Eric V. Smith

gh-85984 [https://github.com/python/cpython/issues/85984]: New function os.login_tty() for Unix.

gh-92128 [https://github.com/python/cpython/issues/92128]: Add __class_getitem__() to logging.LoggerAdapter and logging.StreamHandler, allowing them to be parameterized at runtime. Patch by Alex Waygood.

gh-92049 [https://github.com/python/cpython/issues/92049]: Forbid pickling constants re._constants.SUCCESS etc. Previously, pickling did not fail, but the result could not be unpickled.

gh-92062 [https://github.com/python/cpython/issues/92062]: inspect.Parameter now raises ValueError if name is a keyword, in addition to the existing check that it is an identifier.

gh-87390 [https://github.com/python/cpython/issues/87390]: Add an __unpacked__ attribute to types.GenericAlias. Patch by Jelle Zijlstra.

gh-88089 [https://github.com/python/cpython/issues/88089]: Add support for generic typing.NamedTuple.

gh-91996 [https://github.com/python/cpython/issues/91996]: New http.HTTPMethod enum to represent all the available HTTP request methods in a convenient way

gh-91984 [https://github.com/python/cpython/issues/91984]: Modified test strings in test_argparse.py to not contain trailing spaces before end of line.

gh-91952 [https://github.com/python/cpython/issues/91952]: Add encoding="locale" support to TextIOWrapper.reconfigure().

gh-91954 [https://github.com/python/cpython/issues/91954]: Add encoding and errors arguments to subprocess.getoutput() and subprocess.getstatusoutput().

bpo-47029 [https://bugs.python.org/issue?@action=redirect&bpo=47029]: Always close the read end of the pipe used by multiprocessing.Queue after the last write of buffered data to the write end of the pipe to avoid BrokenPipeError at garbage collection and at multiprocessing.Queue.close() calls. Patch by Géry Ogam.

gh-91928 [https://github.com/python/cpython/issues/91928]: Add datetime.UTC alias for datetime.timezone.utc.

Patch by Kabir Kwatra.

gh-68966 [https://github.com/python/cpython/issues/68966]: The mailcap module is now deprecated and will be removed in Python 3.13. See PEP 594 [https://peps.python.org/pep-0594/] for the rationale and the mimetypes module for an alternative. Patch by Victor Stinner.

gh-91401 [https://github.com/python/cpython/issues/91401]: Provide a way to disable subprocess use of vfork() just in case it is ever needed and document the existing mechanism for posix_spawn().

gh-64783 [https://github.com/python/cpython/issues/64783]: Fix signal.NSIG value on FreeBSD to accept signal numbers greater than 32, like signal.SIGRTMIN and signal.SIGRTMAX. Patch by Victor Stinner.

gh-91910 [https://github.com/python/cpython/issues/91910]: Add missing f prefix to f-strings in error messages from the multiprocessing and asyncio modules.

gh-91860 [https://github.com/python/cpython/issues/91860]: Add typing.dataclass_transform(), implementing PEP 681 [https://peps.python.org/pep-0681/]. Patch by Jelle Zijlstra.

gh-91832 [https://github.com/python/cpython/issues/91832]: Add required attribute to argparse.Action repr output.

gh-91827 [https://github.com/python/cpython/issues/91827]: In the tkinter module add method info_patchlevel() which returns the exact version of the Tcl library as a named tuple similar to sys.version_info.

gh-84461 [https://github.com/python/cpython/issues/84461]: Add --enable-wasm-pthreads to enable pthreads support for WASM builds. Emscripten/node no longer has threading enabled by default. Include additional file systems.

gh-91821 [https://github.com/python/cpython/issues/91821]: Fix unstable test_from_tuple test in test_decimal.py.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the xdrlib module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the uu module.

gh-91760 [https://github.com/python/cpython/issues/91760]: More strict rules will be applied for numerical group references and group names in regular expressions. For now, a deprecation warning is emitted for group references and group names which will be errors in future Python versions.

gh-84461 [https://github.com/python/cpython/issues/84461]: Add provisional sys._emscripten_info named tuple with build-time and run-time information about Emscripten platform.

gh-90623 [https://github.com/python/cpython/issues/90623]: signal.raise_signal() and os.kill() now check immediately for pending signals. Patch by Victor Stinner.

gh-91734 [https://github.com/python/cpython/issues/91734]: Fix OSS audio support on Solaris.

gh-90633 [https://github.com/python/cpython/issues/90633]: Include the passed value in the exception thrown by typing.assert_never(). Patch by Jelle Zijlstra.

gh-91700 [https://github.com/python/cpython/issues/91700]: Compilation of regular expression containing a conditional expression (?(group)...) now raises an appropriate re.error if the group number refers to not defined group. Previously an internal RuntimeError was raised.

gh-91231 [https://github.com/python/cpython/issues/91231]: Add an optional keyword shutdown_timeout parameter to the multiprocessing.BaseManager constructor. Kill the process if terminate() takes longer than the timeout. Patch by Victor Stinner.

gh-91621 [https://github.com/python/cpython/issues/91621]: Fix typing.get_type_hints() for collections.abc.Callable. Patch by Shantanu Jain.

gh-90568 [https://github.com/python/cpython/issues/90568]: Parsing \N escapes of Unicode Named Character Sequences in a regular expression raises now re.error instead of TypeError.

gh-91670 [https://github.com/python/cpython/issues/91670]: Remove deprecated SO config variable in sysconfig.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the telnetlib module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the sunau module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the spwd module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the sndhdr module, as well as inline needed functionality for email.mime.MIMEAudio.

gh-91616 [https://github.com/python/cpython/issues/91616]: re module, fix fullmatch() mismatch when using Atomic Grouping or Possessive Quantifiers.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the ‘pipes’ module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the ossaudiodev module.

bpo-47256 [https://bugs.python.org/issue?@action=redirect&bpo=47256]: re module, limit the maximum capturing group to 1,073,741,823 in 64-bit build, this increases the depth of backtracking.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the nis module.

gh-91595 [https://github.com/python/cpython/issues/91595]: Fix the comparison of character and integer inside Tools.gdb.libpython.write_repr(). Patch by Yu Liu.

gh-74166 [https://github.com/python/cpython/issues/74166]: Add option to raise all errors from create_connection() in an ExceptionGroup when it fails to create a connection. The default remains to raise only the last error that had occurred when multiple addresses were tried.

gh-91487 [https://github.com/python/cpython/issues/91487]: Optimize asyncio UDP speed, over 100 times faster when transferring a large file.

gh-91575 [https://github.com/python/cpython/issues/91575]: Update case-insensitive matching in the re module to the latest Unicode version.

gh-90622 [https://github.com/python/cpython/issues/90622]: In concurrent.futures.process.ProcessPoolExecutor disallow the “fork” multiprocessing start method when the new max_tasks_per_child feature is used as the mix of threads+fork can hang the child processes. Default to using the safe “spawn” start method in that circumstance if no mp_context was supplied.

gh-89022 [https://github.com/python/cpython/issues/89022]: In sqlite3, SQLITE_MISUSE result codes are now mapped to InterfaceError instead of ProgrammingError. Also, more accurate exceptions are raised when binding parameters fail. Patch by Erlend E. Aasland.

gh-91526 [https://github.com/python/cpython/issues/91526]: Stop calling os.device_encoding(file.fileno()) in TextIOWrapper. It was complex, never documented, and didn’t work for most cases. (Patch by Inada Naoki.)

gh-88116 [https://github.com/python/cpython/issues/88116]: Change the frame-related functions in the inspect module to return a regular object (that is backwards compatible with the old tuple-like interface) that include the extended PEP 657 [https://peps.python.org/pep-0657/] position information (end line number, column and end column). The affected functions are: inspect.getframeinfo(), inspect.getouterframes(), inspect.getinnerframes(), inspect.stack() and inspect.trace(). Patch by Pablo Galindo.

gh-69093 [https://github.com/python/cpython/issues/69093]: Add indexing and slicing support to sqlite3.Blob. Patch by Aviv Palivoda and Erlend E. Aasland.

gh-69093 [https://github.com/python/cpython/issues/69093]: Add context manager support to sqlite3.Blob. Patch by Aviv Palivoda and Erlend E. Aasland.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate nntplib.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate msilib.

gh-91404 [https://github.com/python/cpython/issues/91404]: Improve the performance of re matching by using computed gotos (or “threaded code”) on supported platforms and removing expensive pointer indirections.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the imghdr module.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the crypt module.

gh-91276 [https://github.com/python/cpython/issues/91276]: Make space for longer opcodes in dis output.

bpo-47000 [https://bugs.python.org/issue?@action=redirect&bpo=47000]: Make TextIOWrapper uses locale encoding when encoding="locale" is specified even in UTF-8 mode.

gh-91230 [https://github.com/python/cpython/issues/91230]: warnings.catch_warnings() now accepts arguments for warnings.simplefilter(), providing a more concise way to locally ignore warnings or convert them to errors.

gh-91217 [https://github.com/python/cpython/issues/91217]: Deprecate the chunk module.

Add the TCP_CONNECTION_INFO option (available on macOS) to socket.

bpo-47260 [https://bugs.python.org/issue?@action=redirect&bpo=47260]: Fix os.closerange() potentially being a no-op in a Linux seccomp sandbox.

bpo-47087 [https://bugs.python.org/issue?@action=redirect&bpo=47087]: Implement typing.Required and typing.NotRequired (PEP 655 [https://peps.python.org/pep-0655/]). Patch by David Foster and Jelle Zijlstra.

bpo-47061 [https://bugs.python.org/issue?@action=redirect&bpo=47061]: Deprecate cgi and cgitb.

bpo-47061 [https://bugs.python.org/issue?@action=redirect&bpo=47061]: Deprecate audioop.

bpo-47000 [https://bugs.python.org/issue?@action=redirect&bpo=47000]: Add locale.getencoding() to get the current locale encoding. It is similar to locale.getpreferredencoding(False) but ignores the Python UTF-8 Mode.

bpo-42012 [https://bugs.python.org/issue?@action=redirect&bpo=42012]: Add wsgiref.types, containing WSGI-specific types for static type checking.

bpo-47227 [https://bugs.python.org/issue?@action=redirect&bpo=47227]: Suppress expression chaining for more re parsing errors.

bpo-47211 [https://bugs.python.org/issue?@action=redirect&bpo=47211]: Remove undocumented and never working function re.template() and flag re.TEMPLATE. This was later reverted in 3.11.0b2 and deprecated instead.

bpo-47135 [https://bugs.python.org/issue?@action=redirect&bpo=47135]: decimal.localcontext() now accepts context attributes via keyword arguments

bpo-43323 [https://bugs.python.org/issue?@action=redirect&bpo=43323]: Fix errors in the email module if the charset itself contains undecodable/unencodable characters.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Disassembly of quickened code.

bpo-46681 [https://bugs.python.org/issue?@action=redirect&bpo=46681]: Forward gzip.compress() compresslevel to zlib.

bpo-45100 [https://bugs.python.org/issue?@action=redirect&bpo=45100]: Add typing.get_overloads() and typing.clear_overloads(). Patch by Jelle Zijlstra.

bpo-44807 [https://bugs.python.org/issue?@action=redirect&bpo=44807]: typing.Protocol no longer silently replaces __init__() methods defined on subclasses. Patch by Adrian Garcia Badaracco.

bpo-46787 [https://bugs.python.org/issue?@action=redirect&bpo=46787]: Fix concurrent.futures.ProcessPoolExecutor exception memory leak

bpo-46720 [https://bugs.python.org/issue?@action=redirect&bpo=46720]: Add support for path-like objects to multiprocessing.set_executable() for Windows to be on a par with Unix-like systems. Patch by Géry Ogam.

bpo-46696 [https://bugs.python.org/issue?@action=redirect&bpo=46696]: Add SO_INCOMING_CPU constant to socket.

bpo-46053 [https://bugs.python.org/issue?@action=redirect&bpo=46053]: Fix OSS audio support on NetBSD.

bpo-45639 [https://bugs.python.org/issue?@action=redirect&bpo=45639]: image/avif and image/webp were added to mimetypes.

bpo-46285 [https://bugs.python.org/issue?@action=redirect&bpo=46285]: Add command-line option -p/--protocol to module http.server which specifies the HTTP version to which the server is conformant (HTTP/1.1 conformant servers can now be run from the command-line interface of module http.server). Patch by Géry Ogam.

bpo-44791 [https://bugs.python.org/issue?@action=redirect&bpo=44791]: Accept ellipsis as the last argument of typing.Concatenate.

bpo-46547 [https://bugs.python.org/issue?@action=redirect&bpo=46547]: Remove variables leaking into pydoc.Helper class namespace.

bpo-46415 [https://bugs.python.org/issue?@action=redirect&bpo=46415]: Fix ipaddress.ip_{address,interface,network} raising TypeError instead of ValueError if given invalid tuple as address parameter.

bpo-46075 [https://bugs.python.org/issue?@action=redirect&bpo=46075]: CookieJar with DefaultCookiePolicy now can process cookies from localhost with domain=localhost explicitly specified in Set-Cookie header.

bpo-45995 [https://bugs.python.org/issue?@action=redirect&bpo=45995]: Add a “z” option to the string formatting specification that coerces negative zero floating-point values to positive zero after rounding to the format precision. Contributed by John Belmonte.

bpo-26175 [https://bugs.python.org/issue?@action=redirect&bpo=26175]: Fully implement the io.BufferedIOBase or io.TextIOBase interface for tempfile.SpooledTemporaryFile objects. This lets them work correctly with higher-level layers (like compression modules). Patch by Carey Metcalfe.

bpo-45138 [https://bugs.python.org/issue?@action=redirect&bpo=45138]: Fix a regression in the sqlite3 trace callback where bound parameters were not expanded in the passed statement string. The regression was introduced in Python 3.10 by bpo-40318 [https://bugs.python.org/issue?@action=redirect&bpo=40318]. Patch by Erlend E. Aasland.

bpo-44863 [https://bugs.python.org/issue?@action=redirect&bpo=44863]: Allow TypedDict subclasses to also include Generic as a base class in class based syntax. Thereby allowing the user to define a generic TypedDict, just like a user-defined generic but with TypedDict semantics.

bpo-44587 [https://bugs.python.org/issue?@action=redirect&bpo=44587]: Fix BooleanOptionalAction to not automatically add a default string. If a default string is desired, use a formatter to add it.

bpo-43827 [https://bugs.python.org/issue?@action=redirect&bpo=43827]: All positional-or-keyword parameters to ABCMeta.__new__ are now positional-only to avoid conflicts with keyword arguments to be passed to __init_subclass__().

bpo-43218 [https://bugs.python.org/issue?@action=redirect&bpo=43218]: Prevent creation of a venv whose path contains the PATH separator. This could affect the usage of the activate script. Patch by Dustin Rodrigues.

bpo-38435 [https://bugs.python.org/issue?@action=redirect&bpo=38435]: Add a process_group parameter to subprocess.Popen to help move more things off of the unsafe preexec_fn parameter.

bpo-42066 [https://bugs.python.org/issue?@action=redirect&bpo=42066]: Fix cookies getting sorted in CookieJar.__iter__() which is an extra behavior and not mentioned in RFC 2965 or Netscape cookie protocol. Now the cookies in CookieJar follows the order of the Set-Cookie header. Patch by Iman Kermani.

bpo-40617 [https://bugs.python.org/issue?@action=redirect&bpo=40617]: Add create_window_function() to sqlite3.Connection for creating aggregate window functions. Patch by Erlend E. Aasland.

bpo-40676 [https://bugs.python.org/issue?@action=redirect&bpo=40676]: Convert csv to use Argument Clinic for csv.field_size_limit(), csv.get_dialect(), csv.unregister_dialect() and csv.list_dialects().

bpo-39716 [https://bugs.python.org/issue?@action=redirect&bpo=39716]: Raise an ArgumentError when the same subparser name is added twice to an argparse.ArgumentParser. This is consistent with the (default) behavior when the same option string is added twice to an ArgumentParser.

bpo-36073 [https://bugs.python.org/issue?@action=redirect&bpo=36073]: Raise ProgrammingError instead of segfaulting on recursive usage of cursors in sqlite3 converters. Patch by Sergey Fedoseev.

bpo-34975 [https://bugs.python.org/issue?@action=redirect&bpo=34975]: Adds a start_tls() method to StreamWriter, which upgrades the connection with TLS using the given SSLContext.

bpo-22276 [https://bugs.python.org/issue?@action=redirect&bpo=22276]: Path methods glob() and rglob() return only directories if pattern ends with a pathname components separator (/ or sep). Patch by Eisuke Kawashima.

bpo-24905 [https://bugs.python.org/issue?@action=redirect&bpo=24905]: Add blobopen() to sqlite3.Connection. sqlite3.Blob allows incremental I/O operations on blobs. Patch by Aviv Palivoda and Erlend E. Aasland.

Documentation

gh-91888 [https://github.com/python/cpython/issues/91888]: Add a new gh role to the documentation to link to GitHub issues.

gh-91783 [https://github.com/python/cpython/issues/91783]: Document security issues concerning the use of the function shutil.unpack_archive()

gh-91547 [https://github.com/python/cpython/issues/91547]: Remove “Undocumented modules” page.

gh-91298 [https://github.com/python/cpython/issues/91298]: In importlib.resources.abc, refined the documentation of the Traversable Protocol, applying changes from importlib_resources 5.7.1.

bpo-44347 [https://bugs.python.org/issue?@action=redirect&bpo=44347]: Clarify the meaning of dirs_exist_ok, a kwarg of shutil.copytree().

bpo-36329 [https://bugs.python.org/issue?@action=redirect&bpo=36329]: Remove ‘make -C Doc serve’ in favour of ‘make -C Doc htmlview’

bpo-47189 [https://bugs.python.org/issue?@action=redirect&bpo=47189]: Add a What’s New in Python 3.11 entry for the Faster CPython project. Documentation by Ken Jin and Kumar Aditya.

bpo-38668 [https://bugs.python.org/issue?@action=redirect&bpo=38668]: Update the introduction to documentation for os.path to remove warnings that became irrelevant after the implementations of PEP 383 [https://peps.python.org/pep-0383/] and PEP 529 [https://peps.python.org/pep-0529/].

bpo-47115 [https://bugs.python.org/issue?@action=redirect&bpo=47115]: The documentation now lists which members of C structs are part of the Limited API/Stable ABI.

bpo-46962 [https://bugs.python.org/issue?@action=redirect&bpo=46962]: All docstrings in code snippets are now wrapped into PyDoc_STR to follow the guideline of PEP 7’s Documentation Strings paragraph [https://peps.python.org/pep-0007/#documentation-strings]. Patch by Oleg Iarygin.

bpo-26792 [https://bugs.python.org/issue?@action=redirect&bpo=26792]: Improve the docstrings of runpy.run_module() and runpy.run_path(). Original patch by Andrew Brezovsky.

Tests

gh-92169 [https://github.com/python/cpython/issues/92169]: Use warnings_helper.import_deprecated() to import deprecated modules uniformly in tests. Patch by Hugo van Kemenade.

gh-84461 [https://github.com/python/cpython/issues/84461]: When multiprocessing is enabled, libregrtest can now use a Python executable other than sys.executable via the --python flag.

gh-91904 [https://github.com/python/cpython/issues/91904]: Fix initialization of PYTHONREGRTEST_UNICODE_GUARD which prevented running regression tests on non-UTF-8 locale.

gh-91752 [https://github.com/python/cpython/issues/91752]: Added @requires_zlib to test.test_tools.test_freeze.TestFreeze.

gh-91607 [https://github.com/python/cpython/issues/91607]: Fix test_concurrent_futures to test the correct multiprocessing start method context in several cases where the test logic mixed this up.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Threading tests are now skipped on WASM targets without pthread support.

bpo-47109 [https://bugs.python.org/issue?@action=redirect&bpo=47109]: Test for ctypes.macholib.dyld, ctypes.macholib.dylib, and ctypes.macholib.framework are brought from manual pre-unittest times to ctypes.test location and structure. Patch by Oleg Iarygin.

bpo-29890 [https://bugs.python.org/issue?@action=redirect&bpo=29890]: Add tests for ipaddress.IPv4Interface and ipaddress.IPv6Interface construction with tuple arguments. Original patch and tests by louisom.

Build

gh-89452 [https://github.com/python/cpython/issues/89452]: gdbm-compat is now preferred over ndbm if both are available on the system. This allows avoiding the problematic ndbm.h on macOS.

gh-91731 [https://github.com/python/cpython/issues/91731]: Python is now built with -std=c11 compiler option, rather than -std=c99. Patch by Victor Stinner.

bpo-47152 [https://bugs.python.org/issue?@action=redirect&bpo=47152]: Add script and make target for generating sre_constants.h.

bpo-47103 [https://bugs.python.org/issue?@action=redirect&bpo=47103]: Windows PGInstrument builds now copy a required DLL into the output directory, making it easier to run the profile stage of a PGO build.

Windows

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update Windows installer to use SQLite 3.38.3.

bpo-47239 [https://bugs.python.org/issue?@action=redirect&bpo=47239]: Fixed –list and –list-paths output for 윈도우 용 파이썬 런처 when used in an active virtual environment.

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update Windows installer to use SQLite 3.38.2.

bpo-46785 [https://bugs.python.org/issue?@action=redirect&bpo=46785]: Fix race condition between os.stat() and unlinking a file on Windows, by using errors codes returned by FindFirstFileW() when appropriate in win32_xstat_impl.

bpo-40859 [https://bugs.python.org/issue?@action=redirect&bpo=40859]: Update Windows build to use xz-5.2.5

macOS

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update macOS installer to SQLite 3.38.4.

Tools/Demos

gh-91583 [https://github.com/python/cpython/issues/91583]: Fix regression in the code generated by Argument Clinic for functions with the defining_class parameter.

gh-91575 [https://github.com/python/cpython/issues/91575]: Add script Tools/scripts/generate_re_casefix.py and the make target regen-re for generating additional data for case-insensitive matching according to the current Unicode version.

gh-91551 [https://github.com/python/cpython/issues/91551]: Remove the ancient Pynche color editor. It has moved to https://gitlab.com/warsaw/pynche

C API

gh-88279 [https://github.com/python/cpython/issues/88279]: Deprecate the C functions: PySys_SetArgv(), PySys_SetArgvEx(), PySys_SetPath(). Patch by Victor Stinner.

gh-92154 [https://github.com/python/cpython/issues/92154]: Added the PyCode_GetCode() function. This function does the equivalent of the Python code getattr(code_object, 'co_code').

gh-92173 [https://github.com/python/cpython/issues/92173]: Fix the closure argument to PyEval_EvalCodeEx().

gh-91320 [https://github.com/python/cpython/issues/91320]: Fix C++ compiler warnings about “old-style cast” (g++ -Wold-style-cast) in the Python C API. Use C++ reinterpret_cast<> and static_cast<> casts when the Python C API is used in C++. Patch by Victor Stinner.

gh-80527 [https://github.com/python/cpython/issues/80527]: Mark functions as deprecated by PEP 623 [https://peps.python.org/pep-0623/]: PyUnicode_AS_DATA(), PyUnicode_AS_UNICODE(), PyUnicode_GET_DATA_SIZE(), PyUnicode_GET_SIZE(). Patch by Victor Stinner.

gh-91768 [https://github.com/python/cpython/issues/91768]: Py_REFCNT(), Py_TYPE(), Py_SIZE() and Py_IS_TYPE() functions argument type is now PyObject*, rather than const PyObject*. Patch by Victor Stinner.

gh-91020 [https://github.com/python/cpython/issues/91020]: Add PyBytes_Type.tp_alloc to initialize PyBytesObject.ob_shash for bytes subclasses.

bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421]: Add PyFrame_GetLasti C-API function to access frame object’s f_lasti attribute safely from C code.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: Remove the Include/code.h header file. C extensions should only include the main <Python.h> header file. Patch by Victor Stinner.

bpo-47169 [https://bugs.python.org/issue?@action=redirect&bpo=47169]: PyOS_CheckStack() is now exported in the Stable ABI on Windows.

bpo-47169 [https://bugs.python.org/issue?@action=redirect&bpo=47169]: PyThread_get_thread_native_id() is excluded from the stable ABI on platforms where it doesn’t exist (like Solaris).

bpo-46343 [https://bugs.python.org/issue?@action=redirect&bpo=46343]: Added PyErr_GetHandledException() and PyErr_SetHandledException() as simpler alternatives to PyErr_GetExcInfo() and PyErr_SetExcInfo().

They are included in the stable ABI.

Python 3.11.0 alpha 7

Release date: 2022-04-05

Core and Builtins

bpo-47212 [https://bugs.python.org/issue?@action=redirect&bpo=47212]: Raise IndentationError instead of SyntaxError for a bare except with no following indent. Improve SyntaxError locations for an un-parenthesized generator used as arguments. Patch by Matthieu Dartiailh.

bpo-47186 [https://bugs.python.org/issue?@action=redirect&bpo=47186]: Replace JUMP_IF_NOT_EG_MATCH by CHECK_EG_MATCH + jump.

bpo-47176 [https://bugs.python.org/issue?@action=redirect&bpo=47176]: Emscripten builds cannot handle signals in the usual way due to platform limitations. Python can now handle signals. To use, set Module.Py_EmscriptenSignalBuffer to be a single byte SharedArrayBuffer and set Py_EMSCRIPTEN_SIGNAL_HANDLING to 1. Writing a number into the SharedArrayBuffer will cause the corresponding signal to be raised into the Python thread.

bpo-47186 [https://bugs.python.org/issue?@action=redirect&bpo=47186]: Replace JUMP_IF_NOT_EXC_MATCH by CHECK_EXC_MATCH + jump.

bpo-47120 [https://bugs.python.org/issue?@action=redirect&bpo=47120]: Replace the absolute jump opcode JUMP_NO_INTERRUPT by the relative JUMP_BACKWARD_NO_INTERRUPT.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Avoid unnecessary allocations when comparing code objects.

bpo-47182 [https://bugs.python.org/issue?@action=redirect&bpo=47182]: Fix a crash when using a named unicode character like "\N{digit nine}" after the main interpreter has been initialized a second time.

bpo-47162 [https://bugs.python.org/issue?@action=redirect&bpo=47162]: WebAssembly cannot deal with bad function pointer casts (different count or types of arguments). Python can now use call trampolines to mitigate the problem. Define PY_CALL_TRAMPOLINE to enable call trampolines.

bpo-46775 [https://bugs.python.org/issue?@action=redirect&bpo=46775]: Some Windows system error codes(>= 10000) are now mapped into the correct errno and may now raise a subclass of OSError. Patch by Donghee Na.

bpo-47129 [https://bugs.python.org/issue?@action=redirect&bpo=47129]: Improve error messages in f-string syntax errors concerning empty expressions.

bpo-47117 [https://bugs.python.org/issue?@action=redirect&bpo=47117]: Fix a crash if we fail to decode characters in interactive mode if the tokenizer buffers are uninitialized. Patch by Pablo Galindo.

bpo-47127 [https://bugs.python.org/issue?@action=redirect&bpo=47127]: Speed up calls to c functions with keyword arguments by 25% with specialization. Patch by Kumar Aditya.

bpo-47120 [https://bugs.python.org/issue?@action=redirect&bpo=47120]: Replaced JUMP_ABSOLUTE by the relative jump JUMP_BACKWARD.

bpo-42197 [https://bugs.python.org/issue?@action=redirect&bpo=42197]: PyFrame_FastToLocalsWithError() and PyFrame_LocalsToFast() are no longer called during profiling nor tracing. C code can access the f_locals attribute of PyFrameObject by calling PyFrame_GetLocals().

bpo-47070 [https://bugs.python.org/issue?@action=redirect&bpo=47070]: Improve performance of array_inplace_repeat by reducing the number of invocations of memcpy. Refactor the repeat and inplace repeat methods of array, bytes, bytearray and unicodeobject to use the common _PyBytes_Repeat.

bpo-47053 [https://bugs.python.org/issue?@action=redirect&bpo=47053]: Reduce de-optimization in the specialized BINARY_OP_INPLACE_ADD_UNICODE opcode.

bpo-47045 [https://bugs.python.org/issue?@action=redirect&bpo=47045]: Remove the f_state field from the _PyInterpreterFrame struct. Add the owner field to the _PyInterpreterFrame struct to make ownership explicit to simplify clearing and deallocing frames and generators.

bpo-46968 [https://bugs.python.org/issue?@action=redirect&bpo=46968]: Check for the existence of the “sys/auxv.h” header in faulthandler to avoid compilation problems in systems where this header doesn’t exist. Patch by Pablo Galindo

bpo-46329 [https://bugs.python.org/issue?@action=redirect&bpo=46329]: Use low bit of LOAD_GLOBAL to indicate whether to push a NULL before the global. Helps streamline the call sequence a bit.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Quicken bytecode in-place by storing it as part of the corresponding PyCodeObject.

bpo-47012 [https://bugs.python.org/issue?@action=redirect&bpo=47012]: Speed up iteration of bytes and bytearray by 30%. Patch by Kumar Aditya.

bpo-47009 [https://bugs.python.org/issue?@action=redirect&bpo=47009]: Improved the performance of list.append() and list comprehensions by optimizing for the common case, where no resize is needed. Patch by Dennis Sweeney.

bpo-47005 [https://bugs.python.org/issue?@action=redirect&bpo=47005]: Improve performance of bytearray_repeat and bytearray_irepeat by reducing the number of invocations of memcpy.

bpo-46829 [https://bugs.python.org/issue?@action=redirect&bpo=46829]: Deprecate passing a message into asyncio.Future.cancel() and asyncio.Task.cancel()

bpo-46993 [https://bugs.python.org/issue?@action=redirect&bpo=46993]: Speed up bytearray creation from list and tuple by 40%. Patch by Kumar Aditya.

bpo-39829 [https://bugs.python.org/issue?@action=redirect&bpo=39829]: Removed the __len__() call when initializing a list and moved initializing to list_extend. Patch by Jeremiah Pascual.

bpo-46944 [https://bugs.python.org/issue?@action=redirect&bpo=46944]: Speed up throwing exception in generator with METH_FASTCALL calling convention. Patch by Kumar Aditya.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Modify STORE_SUBSCR to use an inline cache entry (rather than its oparg) as an adaptive counter.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline caching for PRECALL and CALL, and remove the internal machinery for managing the (now unused) non-inline caches.

bpo-46881 [https://bugs.python.org/issue?@action=redirect&bpo=46881]: Statically allocate and initialize the latin1 characters.

bpo-46838 [https://bugs.python.org/issue?@action=redirect&bpo=46838]: Improve syntax errors for incorrect function definitions. Patch by Pablo Galindo

bpo-43721 [https://bugs.python.org/issue?@action=redirect&bpo=43721]: Fix docstrings of getter, setter, and deleter to clarify that they create a new copy of the property.

bpo-43224 [https://bugs.python.org/issue?@action=redirect&bpo=43224]: Make grammar changes required for PEP 646.

Library

bpo-47208 [https://bugs.python.org/issue?@action=redirect&bpo=47208]: Allow vendors to override CTYPES_MAX_ARGCOUNT.

bpo-23689 [https://bugs.python.org/issue?@action=redirect&bpo=23689]: re module: fix memory leak when a match is terminated by a signal or memory allocation failure. Patch by Ma Lin.

bpo-47167 [https://bugs.python.org/issue?@action=redirect&bpo=47167]: Allow overriding a future compliance check in asyncio.Task.

bpo-47151 [https://bugs.python.org/issue?@action=redirect&bpo=47151]: When subprocess tries to use vfork, it now falls back to fork if vfork returns an error. This allows use in situations where vfork isn’t allowed by the OS kernel.

bpo-47152 [https://bugs.python.org/issue?@action=redirect&bpo=47152]: Convert the re module into a package. Deprecate modules sre_compile, sre_constants and sre_parse.

bpo-4833 [https://bugs.python.org/issue?@action=redirect&bpo=4833]: Add ZipFile.mkdir()

bpo-27929 [https://bugs.python.org/issue?@action=redirect&bpo=27929]: Fix asyncio.loop.sock_connect() to only resolve names for socket.AF_INET or socket.AF_INET6 families. Resolution may not make sense for other families, like socket.AF_BLUETOOTH and socket.AF_UNIX.

bpo-14265 [https://bugs.python.org/issue?@action=redirect&bpo=14265]: Adds the fully qualified test name to unittest output

bpo-47061 [https://bugs.python.org/issue?@action=redirect&bpo=47061]: Deprecate the aifc module.

bpo-39622 [https://bugs.python.org/issue?@action=redirect&bpo=39622]: Handle Ctrl+C in asyncio programs to interrupt the main task.

bpo-47101 [https://bugs.python.org/issue?@action=redirect&bpo=47101]: hashlib.algorithms_available now lists only algorithms that are provided by activated crypto providers on OpenSSL 3.0. Legacy algorithms are not listed unless the legacy provider has been loaded into the default OSSL context.

bpo-47099 [https://bugs.python.org/issue?@action=redirect&bpo=47099]: All URLError exception messages raised in urllib.request.URLopener now contain a colon between ftp error and the rest of the message. Previously, open_ftp() missed the colon. Patch by Oleg Iarygin.

bpo-47099 [https://bugs.python.org/issue?@action=redirect&bpo=47099]: Exception chaining is changed from Exception.with_traceback()/sys.exc_info() to PEP 3134 [https://peps.python.org/pep-3134/]. Patch by Oleg Iarygin.

bpo-47095 [https://bugs.python.org/issue?@action=redirect&bpo=47095]: hashlib’s internal _blake2 module now prefers libb2 from https://www.blake2.net/ over Python’s vendored copy of blake2.

bpo-47098 [https://bugs.python.org/issue?@action=redirect&bpo=47098]: The Keccak Code Package for hashlib’s internal _sha3 module has been replaced with tiny_sha3. The module is used as fallback when Python is built without OpenSSL.

bpo-47088 [https://bugs.python.org/issue?@action=redirect&bpo=47088]: Implement typing.LiteralString, part of PEP 675 [https://peps.python.org/pep-0675/]. Patch by Jelle Zijlstra.

bpo-42885 [https://bugs.python.org/issue?@action=redirect&bpo=42885]: Optimize re.search(), re.split(), re.findall(), re.finditer() and re.sub() for regular expressions starting with \A or ^.

bpo-23691 [https://bugs.python.org/issue?@action=redirect&bpo=23691]: Protect the re.finditer() iterator from re-entering.

bpo-47067 [https://bugs.python.org/issue?@action=redirect&bpo=47067]: Optimize calling GenericAlias objects by using PEP 590 [https://peps.python.org/pep-0590/] vectorcall and by replacing PyObject_SetAttrString with PyObject_SetAttr.

bpo-28080 [https://bugs.python.org/issue?@action=redirect&bpo=28080]: Add the metadata_encoding parameter in the zipfile.ZipFile constructor and the --metadata-encoding option in the zipfile CLI to allow reading zipfiles using non-standard codecs to encode the filenames within the archive.

bpo-47000 [https://bugs.python.org/issue?@action=redirect&bpo=47000]: Make io.text_encoding() returns “utf-8” when UTF-8 mode is enabled.

bpo-42369 [https://bugs.python.org/issue?@action=redirect&bpo=42369]: Fix thread safety of zipfile._SharedFile.tell() to avoid a “zipfile.BadZipFile: Bad CRC-32 for file” exception when reading a ZipFile from multiple threads.

bpo-38256 [https://bugs.python.org/issue?@action=redirect&bpo=38256]: Fix binascii.crc32() when it is compiled to use zlib’c crc32 to work properly on inputs 4+GiB in length instead of returning the wrong result. The workaround prior to this was to always feed the function data in increments smaller than 4GiB or to just call the zlib module function.

We also have binascii.crc32() release the GIL when computing on larger inputs as zlib.crc32() and hashlib do.

This also boosts performance on Windows as it now uses the zlib crc32 implementation for binascii.crc32() for a 2-3x speedup.

That the stdlib has a crc32 API in two modules is a known historical oddity. This moves us closer to a single implementation behind them.

bpo-47066 [https://bugs.python.org/issue?@action=redirect&bpo=47066]: Global inline flags (e.g. (?i)) can now only be used at the start of the regular expressions. Using them not at the start of expression was deprecated since Python 3.6.

bpo-39394 [https://bugs.python.org/issue?@action=redirect&bpo=39394]: A warning about inline flags not at the start of the regular expression now contains the position of the flag.

bpo-433030 [https://bugs.python.org/issue?@action=redirect&bpo=433030]: Add support of atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) in regular expressions.

bpo-47062 [https://bugs.python.org/issue?@action=redirect&bpo=47062]: Implement asyncio.Runner context manager.

bpo-46382 [https://bugs.python.org/issue?@action=redirect&bpo=46382]: dataclass() slots=True now correctly omits slots already defined in base classes. Patch by Arie Bovenberg.

bpo-47057 [https://bugs.python.org/issue?@action=redirect&bpo=47057]: Use FASTCALL convention for FutureIter.throw()

bpo-47061 [https://bugs.python.org/issue?@action=redirect&bpo=47061]: Deprecate the various modules listed by PEP 594 [https://peps.python.org/pep-0594/]:

aifc, asynchat, asyncore, audioop, cgi, cgitb, chunk, crypt, imghdr, msilib, nntplib, nis, ossaudiodev, pipes, smtpd, sndhdr, spwd, sunau, telnetlib, uu, xdrlib

bpo-34790 [https://bugs.python.org/issue?@action=redirect&bpo=34790]: Remove passing coroutine objects to asyncio.wait().

bpo-47039 [https://bugs.python.org/issue?@action=redirect&bpo=47039]: Normalize repr() of asyncio future and task objects.

bpo-2604 [https://bugs.python.org/issue?@action=redirect&bpo=2604]: Fix bug where doctests using globals would fail when run multiple times.

bpo-45150 [https://bugs.python.org/issue?@action=redirect&bpo=45150]: Add hashlib.file_digest() helper for efficient hashing of file object.

bpo-34861 [https://bugs.python.org/issue?@action=redirect&bpo=34861]: Made cumtime the default sorting key for cProfile

bpo-45997 [https://bugs.python.org/issue?@action=redirect&bpo=45997]: Fix asyncio.Semaphore re-aquiring FIFO order.

bpo-47022 [https://bugs.python.org/issue?@action=redirect&bpo=47022]: The asynchat, asyncore and smtpd modules have been deprecated since at least Python 3.6. Their documentation and deprecation warnings and have now been updated to note they will removed in Python 3.12 (PEP 594 [https://peps.python.org/pep-0594/]).

bpo-43253 [https://bugs.python.org/issue?@action=redirect&bpo=43253]: Fix a crash when closing transports where the underlying socket handle is already invalid on the Proactor event loop.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: select.select() now passes NULL to select for each empty fdset.

bpo-47004 [https://bugs.python.org/issue?@action=redirect&bpo=47004]: Apply bugfixes from importlib_metadata 4.11.3, including bugfix for EntryPoint.extras, which was returning match objects and not the extras strings.

bpo-46998 [https://bugs.python.org/issue?@action=redirect&bpo=46998]: Allow subclassing of typing.Any. Patch by Shantanu Jain.

bpo-46995 [https://bugs.python.org/issue?@action=redirect&bpo=46995]: Deprecate missing asyncio.Task.set_name() for third-party task implementations, schedule making it mandatory in Python 3.13.

bpo-46994 [https://bugs.python.org/issue?@action=redirect&bpo=46994]: Accept explicit contextvars.Context in asyncio.create_task() and asyncio.loop.create_task().

bpo-46981 [https://bugs.python.org/issue?@action=redirect&bpo=46981]: typing.get_args(typing.Tuple[()]) now returns () instead of ((),).

bpo-46968 [https://bugs.python.org/issue?@action=redirect&bpo=46968]: Add os.sysconf_names['SC_MINSIGSTKSZ'].

bpo-46985 [https://bugs.python.org/issue?@action=redirect&bpo=46985]: Upgrade pip wheel bundled with ensurepip (pip 22.0.4)

bpo-46968 [https://bugs.python.org/issue?@action=redirect&bpo=46968]: faulthandler: On Linux 5.14 and newer, dynamically determine size of signal handler stack size CPython allocates using getauxval(AT_MINSIGSTKSZ). This changes allows for Python extension’s request to Linux kernel to use AMX_TILE instruction set on Sapphire Rapids Xeon processor to succeed, unblocking use of the ISA in frameworks.

bpo-46917 [https://bugs.python.org/issue?@action=redirect&bpo=46917]: The math.nan value is now always available. Patch by Victor Stinner.

bpo-46955 [https://bugs.python.org/issue?@action=redirect&bpo=46955]: Expose asyncio.base_events.Server as asyncio.Server. Patch by Stefan Zabka.

bpo-23325 [https://bugs.python.org/issue?@action=redirect&bpo=23325]: The signal module no longer assumes that SIG_IGN and SIG_DFL are small int singletons.

bpo-46932 [https://bugs.python.org/issue?@action=redirect&bpo=46932]: Update bundled libexpat to 2.4.7

bpo-46933 [https://bugs.python.org/issue?@action=redirect&bpo=46933]: The pwd module is now optional. os.path.expanduser() returns the path when the pwd module is not available.

bpo-40059 [https://bugs.python.org/issue?@action=redirect&bpo=40059]: PEP 680 [https://peps.python.org/pep-0680/], the tomllib module. Adds support for parsing TOML.

bpo-464471 [https://bugs.python.org/issue?@action=redirect&bpo=464471]: asyncio.timeout() and asyncio.timeout_at() context managers added. Patch by Tin Tvrtković and Andrew Svetlov.

bpo-46805 [https://bugs.python.org/issue?@action=redirect&bpo=46805]: Added raw datagram socket functions for asyncio: sock_sendto(), sock_recvfrom() and sock_recvfrom_into().

bpo-46644 [https://bugs.python.org/issue?@action=redirect&bpo=46644]: No longer require valid typeforms to be callable. This allows typing.Annotated to wrap typing.ParamSpecArgs and dataclasses.InitVar. Patch by Gregory Beauregard.

bpo-46581 [https://bugs.python.org/issue?@action=redirect&bpo=46581]: Brings ParamSpec propagation for GenericAlias in line with Concatenate (and others).

bpo-45413 [https://bugs.python.org/issue?@action=redirect&bpo=45413]: Define posix_venv and nt_venv sysconfig installation schemes to be used for bootstrapping new virtual environments. Add venv sysconfig installation scheme to get the appropriate one of the above. The schemes are identical to the pre-existing posix_prefix and nt install schemes. The venv module now uses the venv scheme to create new virtual environments instead of hardcoding the paths depending only on the platform. Downstream Python distributors customizing the posix_prefix or nt install scheme in a way that is not compatible with the install scheme used in virtual environments are encouraged not to customize the venv schemes. When Python itself runs in a virtual environment, sysconfig.get_default_scheme() and sysconfig.get_preferred_scheme() with key="prefix" returns venv.

bpo-43224 [https://bugs.python.org/issue?@action=redirect&bpo=43224]: Implement support for PEP 646 in typing.py.

bpo-43224 [https://bugs.python.org/issue?@action=redirect&bpo=43224]: Allow unpacking types.GenericAlias objects, e.g. *tuple[int, str].

bpo-46557 [https://bugs.python.org/issue?@action=redirect&bpo=46557]: Warnings captured by the logging module are now logged without a format string to prevent systems that group logs by the msg argument from grouping captured warnings together.

bpo-41370 [https://bugs.python.org/issue?@action=redirect&bpo=41370]: typing.get_type_hints() now supports evaluating strings as forward references in PEP 585 generic aliases.

bpo-46607 [https://bugs.python.org/issue?@action=redirect&bpo=46607]: Add DeprecationWarning to LegacyInterpolation, deprecated in the docstring since Python 3.2. Will be removed in Python 3.13. Use BasicInterpolation or ExtendedInterpolation instead.

bpo-26120 [https://bugs.python.org/issue?@action=redirect&bpo=26120]: pydoc now excludes __future__ imports from the module’s data items.

bpo-46480 [https://bugs.python.org/issue?@action=redirect&bpo=46480]: Add typing.assert_type(). Patch by Jelle Zijlstra.

bpo-46421 [https://bugs.python.org/issue?@action=redirect&bpo=46421]: Fix a unittest issue where if the command was invoked as python -m unittest and the filename(s) began with a dot (.), a ValueError is returned.

bpo-46245 [https://bugs.python.org/issue?@action=redirect&bpo=46245]: Add optional parameter dir_fd in shutil.rmtree().

bpo-22859 [https://bugs.python.org/issue?@action=redirect&bpo=22859]: unittest.TestProgram.usageExit() is marked as deprecated, to be removed in Python 3.13.

bpo-46170 [https://bugs.python.org/issue?@action=redirect&bpo=46170]: Improve the error message when you try to subclass an instance of typing.NewType.

bpo-40296 [https://bugs.python.org/issue?@action=redirect&bpo=40296]: Fix supporting generic aliases in pydoc.

bpo-20392 [https://bugs.python.org/issue?@action=redirect&bpo=20392]: Fix inconsistency with uppercase file extensions in MimeTypes.guess_type(). Patch by Kumar Aditya.

bpo-46030 [https://bugs.python.org/issue?@action=redirect&bpo=46030]: Add LOCAL_CREDS, LOCAL_CREDS_PERSISTENT and SCM_CREDS2 FreeBSD constants to the socket module.

bpo-44439 [https://bugs.python.org/issue?@action=redirect&bpo=44439]: Fix .write() method of a member file in ZipFile, when the input data is an object that supports the buffer protocol, the file length may be wrong.

bpo-45171 [https://bugs.python.org/issue?@action=redirect&bpo=45171]: Fix handling of the stacklevel argument to logging functions in the logging module so that it is consistent across all logging functions and, as advertised, similar to the stacklevel argument used in warn().

bpo-24959 [https://bugs.python.org/issue?@action=redirect&bpo=24959]: Fix bug where unittest sometimes drops frames from tracebacks of exceptions raised in tests.

bpo-44859 [https://bugs.python.org/issue?@action=redirect&bpo=44859]: Raise more accurate and PEP 249 [https://peps.python.org/pep-0249/] compatible exceptions in sqlite3.

Raise InterfaceError instead of ProgrammingError for SQLITE_MISUSE errors.

Don’t overwrite BufferError with ValueError when conversion to BLOB fails.

Raise ProgrammingError instead of Warning if user tries to execute() more than one SQL statement.

Raise ProgrammingError instead of ValueError if an SQL query contains null characters.

bpo-44493 [https://bugs.python.org/issue?@action=redirect&bpo=44493]: Add missing terminated NUL in sockaddr_un’s length

This was potentially observable when using non-abstract AF_UNIX datagram sockets to processes written in another programming language.

bpo-41930 [https://bugs.python.org/issue?@action=redirect&bpo=41930]: Add serialize() and deserialize() support to sqlite3. Patch by Erlend E. Aasland.

bpo-33178 [https://bugs.python.org/issue?@action=redirect&bpo=33178]: Added ctypes.BigEndianUnion and ctypes.LittleEndianUnion classes, as originally documented in the library docs but not yet implemented.

bpo-43352 [https://bugs.python.org/issue?@action=redirect&bpo=43352]: Add an Barrier object in synchronization primitives of asyncio Lib in order to be consistent with Barrier from threading and multiprocessing libs*

bpo-35859 [https://bugs.python.org/issue?@action=redirect&bpo=35859]: re module, fix a few bugs about capturing group. In rare cases, capturing group gets an incorrect string. Patch by Ma Lin.

Documentation

bpo-45099 [https://bugs.python.org/issue?@action=redirect&bpo=45099]: Document internal asyncio API.

bpo-47126 [https://bugs.python.org/issue?@action=redirect&bpo=47126]: Update PEP URLs to PEP 676 [https://peps.python.org/pep-0676/]’s new canonical form.

bpo-47040 [https://bugs.python.org/issue?@action=redirect&bpo=47040]: Clarified the old Python versions compatibility note of binascii.crc32() / zlib.adler32() / zlib.crc32() functions.

bpo-46033 [https://bugs.python.org/issue?@action=redirect&bpo=46033]: Clarify for statement execution in its doc.

bpo-45790 [https://bugs.python.org/issue?@action=redirect&bpo=45790]: Adjust inaccurate phrasing in 확장형 정의하기: 자습서 about the ob_base field and the macros used to access its contents.

bpo-42340 [https://bugs.python.org/issue?@action=redirect&bpo=42340]: Document that in some circumstances KeyboardInterrupt may cause the code to enter an inconsistent state. Provided a sample workaround to avoid it if needed.

bpo-41233 [https://bugs.python.org/issue?@action=redirect&bpo=41233]: Link the errnos referenced in Doc/library/exceptions.rst to their respective section in Doc/library/errno.rst, and vice versa. Previously this was only done for EINTR and InterruptedError. Patch by Yan “yyyyyyyan” Orestes.

Tests

bpo-47205 [https://bugs.python.org/issue?@action=redirect&bpo=47205]: Skip test for sched_getaffinity() and sched_setaffinity() error case on FreeBSD.

bpo-46126 [https://bugs.python.org/issue?@action=redirect&bpo=46126]: Restore ‘descriptions’ when running tests internally.

bpo-47104 [https://bugs.python.org/issue?@action=redirect&bpo=47104]: Rewrite asyncio.to_thread() tests to use unittest.IsolatedAsyncioTestCase.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: The test suite is now passing on the Emscripten platform. All fork, socket, and subprocess-based tests are skipped.

bpo-47037 [https://bugs.python.org/issue?@action=redirect&bpo=47037]: Skip strftime("%4Y") feature test on Windows. It can cause an assertion error in debug builds.

bpo-46587 [https://bugs.python.org/issue?@action=redirect&bpo=46587]: Skip tests if platform’s strftime does not support non-portable glibc extensions.

bpo-47015 [https://bugs.python.org/issue?@action=redirect&bpo=47015]: A test case for os.sendfile() is converted from deprecated asyncore (see PEP 594 [https://peps.python.org/pep-0594/]) to asyncio. Patch by Oleg Iarygin.

Build

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Add configure option --enable-wasm-dynamic-linking to enable dlopen and MAIN_MODULE / SIDE_MODULE on wasm32-emscripten.

bpo-46023 [https://bugs.python.org/issue?@action=redirect&bpo=46023]: makesetup now detects and skips all duplicated module definitions. The first entry wins.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Add SOABI wasm32-emscripten for Emscripten and wasm32-wasi for WASI on 32bit WASM as well as wasm64 counter parts.

bpo-47032 [https://bugs.python.org/issue?@action=redirect&bpo=47032]: Ensure Windows install builds fail correctly with a non-zero exit code when part of the build fails.

bpo-47024 [https://bugs.python.org/issue?@action=redirect&bpo=47024]: Update OpenSSL to 1.1.1n for macOS installers and all Windows builds.

bpo-46996 [https://bugs.python.org/issue?@action=redirect&bpo=46996]: The tkinter package now requires Tcl/Tk version 8.5.12 or newer.

bpo-46973 [https://bugs.python.org/issue?@action=redirect&bpo=46973]: Add regen-configure make target to regenerate configure script with Christian’s container image quay.io/tiran/cpython_autoconf:269.

bpo-46917 [https://bugs.python.org/issue?@action=redirect&bpo=46917]: Building Python now requires support of IEEE 754 floating-point numbers. Patch by Victor Stinner.

bpo-45774 [https://bugs.python.org/issue?@action=redirect&bpo=45774]: configure now verifies that all SQLite C APIs needed for the sqlite3 extension module are found.

Windows

bpo-47194 [https://bugs.python.org/issue?@action=redirect&bpo=47194]: Update zlib to v1.2.12 to resolve CVE 2018-25032 [https://www.cve.org/CVERecord?id=CVE-2018-25032].

bpo-47171 [https://bugs.python.org/issue?@action=redirect&bpo=47171]: Enables installing the py.exe launcher on Windows ARM64.

bpo-46566 [https://bugs.python.org/issue?@action=redirect&bpo=46566]: Upgraded 윈도우 용 파이썬 런처 to support a new -V:company/tag argument for full PEP 514 [https://peps.python.org/pep-0514/] support and to detect ARM64 installs. The -64 suffix on arguments is deprecated, but still selects any non-32-bit install. Setting PYLAUNCHER_ALLOW_INSTALL and specifying a version that is not installed will attempt to install the requested version from the Microsoft Store.

bpo-47086 [https://bugs.python.org/issue?@action=redirect&bpo=47086]: The installer for Windows now includes documentation as loose HTML files rather than a single compiled .chm file.

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update Windows installer to use SQLite 3.38.1.

bpo-44549 [https://bugs.python.org/issue?@action=redirect&bpo=44549]: Update bzip2 to 1.0.8 in Windows builds to mitigate CVE 2016-3189 [https://www.cve.org/CVERecord?id=CVE-2016-3189] and CVE 2019-12900 [https://www.cve.org/CVERecord?id=CVE-2019-12900].

bpo-46948 [https://bugs.python.org/issue?@action=redirect&bpo=46948]: Prevent CVE 2022-26488 [https://www.cve.org/CVERecord?id=CVE-2022-26488] by ensuring the Add to PATH option in the Windows installer uses the correct path when being repaired.

macOS

bpo-46890 [https://bugs.python.org/issue?@action=redirect&bpo=46890]: Fix a regression in the setting of sys._base_executable in framework builds, and thereby fix a regression in venv virtual environments with such builds.

bpo-46907 [https://bugs.python.org/issue?@action=redirect&bpo=46907]: Update macOS installer to SQLite 3.38.1.

Tools/Demos

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Replace Emscripten’s limited shell with Katie Bell’s browser-ui REPL from python-wasm project.

C API

bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421]: Add PyFrame_GetBuiltins, PyFrame_GetGenerator and PyFrame_GetGlobals C-API functions to access frame object attributes safely from C code.

bpo-46850 [https://bugs.python.org/issue?@action=redirect&bpo=46850]: Move the private _PyFrameEvalFunction type, and private _PyInterpreterState_GetEvalFrameFunc() and _PyInterpreterState_SetEvalFrameFunc() functions to the internal C API. The _PyFrameEvalFunction callback function type now uses the _PyInterpreterFrame type which is part of the internal C API. Patch by Victor Stinner.

bpo-46850 [https://bugs.python.org/issue?@action=redirect&bpo=46850]: Move the private undocumented _PyEval_EvalFrameDefault() function to the internal C API. The function now uses the _PyInterpreterFrame type which is part of the internal C API. Patch by Victor Stinner.

bpo-46850 [https://bugs.python.org/issue?@action=redirect&bpo=46850]: Remove the private undocumented function _PyEval_CallTracing() from the C API. Call the public sys.call_tracing() function instead. Patch by Victor Stinner.

bpo-46850 [https://bugs.python.org/issue?@action=redirect&bpo=46850]: Remove the private undocumented function _PyEval_GetCoroutineOriginTrackingDepth() from the C API. Call the public sys.get_coroutine_origin_tracking_depth() function instead. Patch by Victor Stinner.

bpo-46850 [https://bugs.python.org/issue?@action=redirect&bpo=46850]: Remove the following private undocumented functions from the C API:

_PyEval_GetAsyncGenFirstiter()

_PyEval_GetAsyncGenFinalizer()

_PyEval_SetAsyncGenFirstiter()

_PyEval_SetAsyncGenFinalizer()

Call the public sys.get_asyncgen_hooks() and sys.set_asyncgen_hooks() functions instead. Patch by Victor Stinner.

bpo-46987 [https://bugs.python.org/issue?@action=redirect&bpo=46987]: Remove private functions _PySys_GetObjectId() and _PySys_SetObjectId(). Patch by Donghee Na.

bpo-46906 [https://bugs.python.org/issue?@action=redirect&bpo=46906]: Add new functions to pack and unpack C double (serialize and deserialize): PyFloat_Pack2(), PyFloat_Pack4(), PyFloat_Pack8(), PyFloat_Unpack2(), PyFloat_Unpack4() and PyFloat_Unpack8(). Patch by Victor Stinner.

Python 3.11.0 alpha 6

Release date: 2022-03-07

Core and Builtins

bpo-46940 [https://bugs.python.org/issue?@action=redirect&bpo=46940]: Avoid overriding AttributeError metadata information for nested attribute access calls. Patch by Pablo Galindo.

bpo-46927 [https://bugs.python.org/issue?@action=redirect&bpo=46927]: Include the type’s name in the error message for subscripting non-generic types.

bpo-46921 [https://bugs.python.org/issue?@action=redirect&bpo=46921]: Support vectorcall for super(). Patch by Ken Jin.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Fix incorrect handling of inline cache entries when specializing BINARY_OP.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use an oparg to simplify the construction of helpful error messages in GET_AWAITABLE.

bpo-46903 [https://bugs.python.org/issue?@action=redirect&bpo=46903]: Make sure that str subclasses can be used as attribute names for instances with virtual dictionaries. Fixes regression in 3.11alpha

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Add more detailed specialization failure stats for COMPARE_OP followed by EXTENDED_ARG.

bpo-46891 [https://bugs.python.org/issue?@action=redirect&bpo=46891]: Fix bug introduced during 3.11alpha where subclasses of types.ModuleType with __slots__ were not initialized correctly, resulting in an interpreter crash.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline caching for LOAD_ATTR, LOAD_METHOD, and STORE_ATTR.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline cache for BINARY_SUBSCR.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline caching for COMPARE_OP.

bpo-46864 [https://bugs.python.org/issue?@action=redirect&bpo=46864]: Deprecate PyBytesObject.ob_shash. It will be removed in Python 3.13.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline caching for UNPACK_SEQUENCE.

bpo-46845 [https://bugs.python.org/issue?@action=redirect&bpo=46845]: Reduces dict size by removing hash value from hash table when all inserted keys are Unicode. For example, sys.getsizeof(dict.fromkeys("abcdefg")) becomes 272 bytes from 352 bytes on 64bit platform.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Use inline cache for LOAD_GLOBAL.

bpo-46852 [https://bugs.python.org/issue?@action=redirect&bpo=46852]: Rename the private undocumented float.__set_format__() method to float.__setformat__() to fix a typo introduced in Python 3.7. The method is only used by test_float. Patch by Victor Stinner.

bpo-46852 [https://bugs.python.org/issue?@action=redirect&bpo=46852]: Remove the undocumented private float.__set_format__() method, previously known as float.__setformat__() in Python 3.7. Its docstring said: “You probably don’t want to use this function. It exists mainly to be used in Python’s test suite.” Patch by Victor Stinner.

bpo-40116 [https://bugs.python.org/issue?@action=redirect&bpo=40116]: Fix regression that dict.update(other) may don’t respect iterate order of other when other is key sharing dict.

bpo-46712 [https://bugs.python.org/issue?@action=redirect&bpo=46712]: Share global string identifiers in deep-frozen modules.

bpo-46430 [https://bugs.python.org/issue?@action=redirect&bpo=46430]: Fix memory leak in interned strings of deep-frozen modules.

bpo-46841 [https://bugs.python.org/issue?@action=redirect&bpo=46841]: Store BINARY_OP caches inline using a new CACHE instruction.

bpo-45107 [https://bugs.python.org/issue?@action=redirect&bpo=45107]: Specialize LOAD_METHOD for instances with a dict.

bpo-44337 [https://bugs.python.org/issue?@action=redirect&bpo=44337]: Reduce the memory usage of specialized LOAD_ATTR and STORE_ATTR instructions.

bpo-46729 [https://bugs.python.org/issue?@action=redirect&bpo=46729]: Add number of sub-exceptions to BaseException.__str__().

bpo-45885 [https://bugs.python.org/issue?@action=redirect&bpo=45885]: Don’t un-adapt COMPARE_OP when collecting specialization stats.

bpo-46329 [https://bugs.python.org/issue?@action=redirect&bpo=46329]: Fix specialization stats gathering for PRECALL instructions.

bpo-46794 [https://bugs.python.org/issue?@action=redirect&bpo=46794]: Bump up the libexpat version into 2.4.6

bpo-46823 [https://bugs.python.org/issue?@action=redirect&bpo=46823]: Implement a specialized combined opcode LOAD_FAST__LOAD_ATTR_INSTANCE_VALUE. Patch by Dennis Sweeney.

bpo-46820 [https://bugs.python.org/issue?@action=redirect&bpo=46820]: Fix parsing a numeric literal immediately (without spaces) followed by “not in” keywords, like in 1not in x. Now the parser only emits a warning, not a syntax error.

bpo-46329 [https://bugs.python.org/issue?@action=redirect&bpo=46329]: Move KW_NAMES before PRECALL instruction in call sequence. Change operand of CALL to match PRECALL for easier specialization.

bpo-46808 [https://bugs.python.org/issue?@action=redirect&bpo=46808]: Remove the NEXT_BLOCK macro from compile.c, and make the compiler automatically generate implicit blocks when they are needed.

bpo-46329 [https://bugs.python.org/issue?@action=redirect&bpo=46329]: Add PUSH_NULL instruction. This is used as a prefix when evaluating a callable, so that the stack has the same shape for methods and other calls. PRECALL_FUNCTION and PRECALL_METHOD are merged into a single PRECALL instruction.

There is no change in semantics.

bpo-46762 [https://bugs.python.org/issue?@action=redirect&bpo=46762]: Fix an assert failure in debug builds when a ‘<’, ‘>’, or ‘=’ is the last character in an f-string that’s missing a closing right brace.

bpo-46730 [https://bugs.python.org/issue?@action=redirect&bpo=46730]: Message of AttributeError caused by getting, setting or deleting a property without the corresponding function now mentions that the attribute is in fact a property and also specifies type of the class that it belongs to.

bpo-46724 [https://bugs.python.org/issue?@action=redirect&bpo=46724]: Make sure that all backwards jumps use the JUMP_ABSOLUTE instruction, rather than JUMP_FORWARD with an argument of (2**32)+offset.

bpo-46732 [https://bugs.python.org/issue?@action=redirect&bpo=46732]: Correct the docstring for the __bool__() method. Patch by Jelle Zijlstra.

bpo-46072 [https://bugs.python.org/issue?@action=redirect&bpo=46072]: Add more detailed specialization failure statistics for BINARY_OP.

bpo-46707 [https://bugs.python.org/issue?@action=redirect&bpo=46707]: Avoid potential exponential backtracking when producing some syntax errors involving lots of brackets. Patch by Pablo Galindo.

bpo-46323 [https://bugs.python.org/issue?@action=redirect&bpo=46323]: ctypes now allocates memory on the stack instead of on the heap to pass arguments while calling a Python callback function. Patch by Donghee Na.

bpo-45923 [https://bugs.python.org/issue?@action=redirect&bpo=45923]: Add a quickened form of RESUME that skips quickening checks.

bpo-46702 [https://bugs.python.org/issue?@action=redirect&bpo=46702]: Specialize UNPACK_SEQUENCE for tuple and list unpackings.

bpo-46072 [https://bugs.python.org/issue?@action=redirect&bpo=46072]: Opcode pair stats are now gathered with --enable-pystats. Defining DYNAMIC_EXECUTION_PROFILE or DXPAIRS no longer has any effect.

bpo-46675 [https://bugs.python.org/issue?@action=redirect&bpo=46675]: Allow more than 16 items in a split dict before it is combined. The limit is now 254.

bpo-40479 [https://bugs.python.org/issue?@action=redirect&bpo=40479]: Add a missing call to va_end() in Modules/_hashopenssl.c.

bpo-46323 [https://bugs.python.org/issue?@action=redirect&bpo=46323]: Use PyObject_Vectorcall() while calling ctypes callback function. Patch by Donghee Na.

bpo-46615 [https://bugs.python.org/issue?@action=redirect&bpo=46615]: When iterating over sets internally in setobject.c, acquire strong references to the resulting items from the set. This prevents crashes in corner-cases of various set operations where the set gets mutated.

bpo-45828 [https://bugs.python.org/issue?@action=redirect&bpo=45828]: The bytecode compiler now attempts to apply runtime stack manipulations at compile-time (whenever it is feasible to do so).

bpo-30496 [https://bugs.python.org/issue?@action=redirect&bpo=30496]: Fixed a minor portability issue in the implementation of PyLong_FromLong(), and added a fast path for single-digit integers to PyLong_FromLongLong().

Library

bpo-25707 [https://bugs.python.org/issue?@action=redirect&bpo=25707]: Fixed a file leak in xml.etree.ElementTree.iterparse() when the iterator is not exhausted. Patch by Jacob Walls.

bpo-46877 [https://bugs.python.org/issue?@action=redirect&bpo=46877]: Export unittest.doModuleCleanups() in unittest. Patch by Kumar Aditya.

bpo-46848 [https://bugs.python.org/issue?@action=redirect&bpo=46848]: For performance, use the optimized string-searching implementations from find() and rfind() for find() and rfind().

bpo-46736 [https://bugs.python.org/issue?@action=redirect&bpo=46736]: SimpleHTTPRequestHandler now uses HTML5 grammar. Patch by Donghee Na.

bpo-44886 [https://bugs.python.org/issue?@action=redirect&bpo=44886]: Inherit asyncio proactor datagram transport from asyncio.DatagramTransport.

bpo-46827 [https://bugs.python.org/issue?@action=redirect&bpo=46827]: Support UDP sockets in asyncio.loop.sock_connect() for selector-based event loops. Patch by Thomas Grainger.

bpo-46811 [https://bugs.python.org/issue?@action=redirect&bpo=46811]: Make test suite support Expat >=2.4.5

bpo-46252 [https://bugs.python.org/issue?@action=redirect&bpo=46252]: Raise TypeError if ssl.SSLSocket is passed to transport-based APIs.

bpo-46784 [https://bugs.python.org/issue?@action=redirect&bpo=46784]: Fix libexpat symbols collisions with user dynamically loaded or statically linked libexpat in embedded Python.

bpo-46786 [https://bugs.python.org/issue?@action=redirect&bpo=46786]: The HTML serialisation in xml.etree.ElementTree now writes embed, source, track and wbr as empty tags, as defined in HTML 5.

bpo-39327 [https://bugs.python.org/issue?@action=redirect&bpo=39327]: shutil.rmtree() can now work with VirtualBox shared folders when running from the guest operating-system.

bpo-45390 [https://bugs.python.org/issue?@action=redirect&bpo=45390]: Propagate asyncio.CancelledError message from inner task to outer awaiter.

bpo-46756 [https://bugs.python.org/issue?@action=redirect&bpo=46756]: Fix a bug in urllib.request.HTTPPasswordMgr.find_user_password() and urllib.request.HTTPPasswordMgrWithPriorAuth.is_authenticated() which allowed to bypass authorization. For example, access to URI example.org/foobar was allowed if the user was authorized for URI example.org/foo.

bpo-46737 [https://bugs.python.org/issue?@action=redirect&bpo=46737]: random.gauss() and random.normalvariate() now have default arguments.

bpo-46752 [https://bugs.python.org/issue?@action=redirect&bpo=46752]: Add task groups to asyncio (structured concurrency, inspired by Trio’s nurseries). This also introduces a change to task cancellation, where a cancelled task can’t be cancelled again until it calls .uncancel().

bpo-46724 [https://bugs.python.org/issue?@action=redirect&bpo=46724]: Fix dis behavior on negative jump offsets.

bpo-46333 [https://bugs.python.org/issue?@action=redirect&bpo=46333]: The __repr__() method of typing.ForwardRef now includes the module parameter of typing.ForwardRef when it is set.

bpo-46643 [https://bugs.python.org/issue?@action=redirect&bpo=46643]: In typing.get_type_hints(), support evaluating stringified ParamSpecArgs and ParamSpecKwargs annotations. Patch by Gregory Beauregard.

bpo-45863 [https://bugs.python.org/issue?@action=redirect&bpo=45863]: When the tarfile module creates a pax format archive, it will put an integer representation of timestamps in the ustar header (if possible) for the benefit of older unarchivers, in addition to the existing full-precision timestamps in the pax extended header.

bpo-46066 [https://bugs.python.org/issue?@action=redirect&bpo=46066]: Deprecate kwargs-based syntax for typing.TypedDict definitions. It had confusing semantics when specifying totality, and was largely unused. Patch by Jingchen Ye.

bpo-46676 [https://bugs.python.org/issue?@action=redirect&bpo=46676]: Make typing.ParamSpec args and kwargs equal to themselves. Patch by Gregory Beauregard.

bpo-46323 [https://bugs.python.org/issue?@action=redirect&bpo=46323]: ctypes.CFUNCTYPE() and ctypes.WINFUNCTYPE() now fail to create the type if its _argtypes_ member contains too many arguments. Previously, the error was only raised when calling a function. Patch by Victor Stinner.

bpo-46672 [https://bugs.python.org/issue?@action=redirect&bpo=46672]: Fix NameError in asyncio.gather() when initial type check fails.

bpo-46659 [https://bugs.python.org/issue?@action=redirect&bpo=46659]: The calendar.LocaleTextCalendar and calendar.LocaleHTMLCalendar classes now use locale.getlocale(), instead of using locale.getdefaultlocale(), if no locale is specified. Patch by Victor Stinner.

bpo-46659 [https://bugs.python.org/issue?@action=redirect&bpo=46659]: The locale.getdefaultlocale() function is deprecated and will be removed in Python 3.13. Use locale.setlocale(), locale.getpreferredencoding(False) and locale.getlocale() functions instead. Patch by Victor Stinner.

bpo-46655 [https://bugs.python.org/issue?@action=redirect&bpo=46655]: In typing.get_type_hints(), support evaluating bare stringified TypeAlias annotations. Patch by Gregory Beauregard.

bpo-45948 [https://bugs.python.org/issue?@action=redirect&bpo=45948]: Fixed a discrepancy in the C implementation of the xml.etree.ElementTree module. Now, instantiating an xml.etree.ElementTree.XMLParser with a target=None keyword provides a default xml.etree.ElementTree.TreeBuilder target as the Python implementation does.

bpo-46626 [https://bugs.python.org/issue?@action=redirect&bpo=46626]: Expose Linux’s IP_BIND_ADDRESS_NO_PORT option in socket.

bpo-46521 [https://bugs.python.org/issue?@action=redirect&bpo=46521]: Fix a bug in the codeop module that was incorrectly identifying invalid code involving string quotes as valid code.

bpo-46571 [https://bugs.python.org/issue?@action=redirect&bpo=46571]: Improve typing.no_type_check().

Now it does not modify external classes and functions. We also now correctly mark classmethods as not to be type checked.

bpo-46400 [https://bugs.python.org/issue?@action=redirect&bpo=46400]: expat: Update libexpat from 2.4.1 to 2.4.4

bpo-46556 [https://bugs.python.org/issue?@action=redirect&bpo=46556]: Deprecate undocumented support for using a pathlib.Path object as a context manager.

bpo-46534 [https://bugs.python.org/issue?@action=redirect&bpo=46534]: Implement PEP 673 [https://peps.python.org/pep-0673/] typing.Self. Patch by James Hilton-Balfe.

bpo-46522 [https://bugs.python.org/issue?@action=redirect&bpo=46522]: Make various module __getattr__ AttributeErrors more closely match a typical AttributeError

bpo-46475 [https://bugs.python.org/issue?@action=redirect&bpo=46475]: Add typing.Never and typing.assert_never(). Patch by Jelle Zijlstra.

bpo-46333 [https://bugs.python.org/issue?@action=redirect&bpo=46333]: The __eq__() and __hash__() methods of typing.ForwardRef now honor the module parameter of typing.ForwardRef. Forward references from different modules are now differentiated.

bpo-46246 [https://bugs.python.org/issue?@action=redirect&bpo=46246]: Add missing __slots__ to importlib.metadata.DeprecatedList. Patch by Arie Bovenberg.

bpo-46232 [https://bugs.python.org/issue?@action=redirect&bpo=46232]: The ssl module now handles certificates with bit strings in DN correctly.

bpo-46195 [https://bugs.python.org/issue?@action=redirect&bpo=46195]: typing.get_type_hints() no longer adds Optional to parameters with None as a default. This aligns to changes to PEP 484 in https://github.com/python/peps/pull/689

bpo-31369 [https://bugs.python.org/issue?@action=redirect&bpo=31369]: Add RegexFlag to re.__all__ and documented it. Add NOFLAG to indicate no flags being set.

bpo-45898 [https://bugs.python.org/issue?@action=redirect&bpo=45898]: ctypes no longer defines ffi_type_* symbols in cfield.c. The symbols have been provided by libffi for over a decade.

bpo-44953 [https://bugs.python.org/issue?@action=redirect&bpo=44953]: Calling operator.itemgetter objects and operator.attrgetter objects is now faster due to use of the vectorcall calling convention.

bpo-44289 [https://bugs.python.org/issue?@action=redirect&bpo=44289]: Fix an issue with is_tarfile() method when using fileobj argument: position in the fileobj was advanced forward which made it unreadable with tarfile.TarFile.open().

bpo-44011 [https://bugs.python.org/issue?@action=redirect&bpo=44011]: Reimplement SSL/TLS support in asyncio, borrow the implementation from uvloop library.

bpo-41086 [https://bugs.python.org/issue?@action=redirect&bpo=41086]: Make the configparser.ConfigParser constructor raise TypeError if the interpolation parameter is not of type configparser.Interpolation

bpo-29418 [https://bugs.python.org/issue?@action=redirect&bpo=29418]: Implement inspect.ismethodwrapper() and fix inspect.isroutine() for cases where methodwrapper is given. Patch by Hakan Çelik.

bpo-14156 [https://bugs.python.org/issue?@action=redirect&bpo=14156]: argparse.FileType now supports an argument of ‘-’ in binary mode, returning the .buffer attribute of sys.stdin/sys.stdout as appropriate. Modes including ‘x’ and ‘a’ are treated equivalently to ‘w’ when argument is ‘-’. Patch contributed by Josh Rosenberg

Documentation

bpo-42238 [https://bugs.python.org/issue?@action=redirect&bpo=42238]: Doc/tools/rstlint.py has moved to its own repository and is now packaged on PyPI as sphinx-lint.

Tests

bpo-46913 [https://bugs.python.org/issue?@action=redirect&bpo=46913]: Fix test_faulthandler.test_sigfpe() if Python is built with undefined behavior sanitizer (UBSAN): disable UBSAN on the faulthandler_sigfpe() function. Patch by Victor Stinner.

bpo-46760 [https://bugs.python.org/issue?@action=redirect&bpo=46760]: Remove bytecode offsets from expected values in test.test_dis module. Reduces the obstacles to modifying the VM or compiler.

bpo-46708 [https://bugs.python.org/issue?@action=redirect&bpo=46708]: Prevent default asyncio event loop policy modification warning after test_asyncio execution.

bpo-46678 [https://bugs.python.org/issue?@action=redirect&bpo=46678]: The function make_legacy_pyc in Lib/test/support/import_helper.py no longer fails when PYTHONPYCACHEPREFIX is set to a directory on a different device from where tempfiles are stored.

bpo-46623 [https://bugs.python.org/issue?@action=redirect&bpo=46623]: Skip test_pair() and test_speech128() of test_zlib on s390x since they fail if zlib uses the s390x hardware accelerator. Patch by Victor Stinner.

Build

bpo-46860 [https://bugs.python.org/issue?@action=redirect&bpo=46860]: Respect --with-suffix when building on case-insensitive file systems.

bpo-46656 [https://bugs.python.org/issue?@action=redirect&bpo=46656]: Building Python now requires a C11 compiler. Optional C11 features are not required. Patch by Victor Stinner.

bpo-46656 [https://bugs.python.org/issue?@action=redirect&bpo=46656]: Building Python now requires support for floating-point Not-a-Number (NaN): remove the Py_NO_NAN macro. Patch by Victor Stinner.

bpo-46640 [https://bugs.python.org/issue?@action=redirect&bpo=46640]: Building Python now requires a C99 <math.h> header file providing a NAN constant, or the __builtin_nan() built-in function. Patch by Victor Stinner.

bpo-46608 [https://bugs.python.org/issue?@action=redirect&bpo=46608]: Exclude marshalled-frozen data if deep-freezing to save 300 KB disk space. This includes adding a new is_package field to _frozen. Patch by Kumar Aditya.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Fix wasm32-emscripten test failures and platform issues. - Disable syscalls that are not supported or don’t work, e.g. wait, getrusage, prlimit, mkfifo, mknod, setres[gu]id, setgroups. - Use fd_count to count open fds. - Add more checks for subprocess and fork. - Add workarounds for missing _multiprocessing and failing socket.accept(). - Enable bzip2. - Disable large file support. - Disable signal.alarm.

bpo-46430 [https://bugs.python.org/issue?@action=redirect&bpo=46430]: Intern strings in deep-frozen modules. Patch by Kumar Aditya.

Windows

bpo-46744 [https://bugs.python.org/issue?@action=redirect&bpo=46744]: The default all users install directory for ARM64 is now under the native Program Files folder, rather than Program Files (Arm) which is intended for ARM (32-bit) files.

bpo-46567 [https://bugs.python.org/issue?@action=redirect&bpo=46567]: Adds Tcl and Tk support for Windows ARM64. This also adds IDLE to the installation.

bpo-46638 [https://bugs.python.org/issue?@action=redirect&bpo=46638]: Ensures registry virtualization is consistently disabled. For 3.10 and earlier, it remains enabled (some registry writes are protected), while for 3.11 and later it is disabled (registry modifications affect all applications).

IDLE

bpo-46630 [https://bugs.python.org/issue?@action=redirect&bpo=46630]: Make query dialogs on Windows start with a cursor in the entry box.

bpo-45447 [https://bugs.python.org/issue?@action=redirect&bpo=45447]: Apply IDLE syntax highlighting to .pyi files. Patch by Alex Waygood and Terry Jan Reedy.

C API

bpo-46748 [https://bugs.python.org/issue?@action=redirect&bpo=46748]: Python’s public headers no longer import <stdbool.h>, leaving code that embeds/extends Python free to define bool, true and false.

bpo-46836 [https://bugs.python.org/issue?@action=redirect&bpo=46836]: Move the PyFrameObject type definition (struct _frame) to the internal C API pycore_frame.h header file. Patch by Victor Stinner.

bpo-45459 [https://bugs.python.org/issue?@action=redirect&bpo=45459]: Rename Include/buffer.h header file to Include/pybuffer.h to avoid conflicts with projects having an existing buffer.h header file. Patch by Victor Stinner.

bpo-45412 [https://bugs.python.org/issue?@action=redirect&bpo=45412]: Remove the HAVE_PY_SET_53BIT_PRECISION macro (moved to the internal C API). Patch by Victor Stinner.

bpo-46613 [https://bugs.python.org/issue?@action=redirect&bpo=46613]: Added function PyType_GetModuleByDef(), which allows access to module state when a method’s defining class is not available.

Python 3.11.0 alpha 5

Release date: 2022-02-03

Core and Builtins

bpo-45773 [https://bugs.python.org/issue?@action=redirect&bpo=45773]: Remove two invalid “peephole” optimizations from the bytecode compiler.

bpo-46564 [https://bugs.python.org/issue?@action=redirect&bpo=46564]: Do not create frame objects when creating super object. Patch by Kumar Aditya.

bpo-45885 [https://bugs.python.org/issue?@action=redirect&bpo=45885]: Added more fined-grained specialization failure stats regarding the COMPARE_OP bytecode.

bpo-44977 [https://bugs.python.org/issue?@action=redirect&bpo=44977]: The delegation of int() to __trunc__() is now deprecated. Calling int(a) when type(a) implements __trunc__() but not __int__() or __index__() now raises a DeprecationWarning.

bpo-46458 [https://bugs.python.org/issue?@action=redirect&bpo=46458]: Reorder code emitted by the compiler for a try-except block so that the else block’s code immediately follows the try body (without a jump). This is more optimal for the happy path.

bpo-46527 [https://bugs.python.org/issue?@action=redirect&bpo=46527]: Allow passing iterable as a keyword argument to enumerate() again. Patch by Jelle Zijlstra.

bpo-46528 [https://bugs.python.org/issue?@action=redirect&bpo=46528]: Replace several stack manipulation instructions (DUP_TOP, DUP_TOP_TWO, ROT_TWO, ROT_THREE, ROT_FOUR, and ROT_N) with new COPY and SWAP instructions.

bpo-46329 [https://bugs.python.org/issue?@action=redirect&bpo=46329]: Use two or three bytecodes to implement most calls.

Calls without named arguments are implemented as a sequence of two instructions: PRECALL; CALL. Calls with named arguments are implemented as a sequence of three instructions: PRECALL; KW_NAMES; CALL. There are two different PRECALL instructions: PRECALL_FUNTION and PRECALL_METHOD. The latter pairs with LOAD_METHOD.

This partition into pre-call and call allows better specialization, and thus better performance ultimately.

There is no change in semantics.

bpo-46503 [https://bugs.python.org/issue?@action=redirect&bpo=46503]: Fix an assert when parsing some invalid N escape sequences in f-strings.

bpo-46431 [https://bugs.python.org/issue?@action=redirect&bpo=46431]: Improve error message on invalid calls to BaseExceptionGroup.__new__().

bpo-46476 [https://bugs.python.org/issue?@action=redirect&bpo=46476]: Fix memory leak in code objects generated by deepfreeze. Patch by Kumar Aditya.

bpo-46481 [https://bugs.python.org/issue?@action=redirect&bpo=46481]: Speed up calls to weakref.ref.__call__() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-46417 [https://bugs.python.org/issue?@action=redirect&bpo=46417]: Fix a race condition on setting a type __bases__ attribute: the internal function add_subclass() now gets the PyTypeObject.tp_subclasses member after calling PyWeakref_NewRef() which can trigger a garbage collection which can indirectly modify PyTypeObject.tp_subclasses. Patch by Victor Stinner.

bpo-46417 [https://bugs.python.org/issue?@action=redirect&bpo=46417]: python -X showrefcount now shows the total reference count after clearing and destroyed the main Python interpreter. Previously, it was shown before. Patch by Victor Stinner.

bpo-43683 [https://bugs.python.org/issue?@action=redirect&bpo=43683]: Add ASYNC_GEN_WRAP opcode to wrap the value to be yielded in async generators. Removes the need to special case async generators in the YIELD_VALUE instruction.

bpo-46407 [https://bugs.python.org/issue?@action=redirect&bpo=46407]: Optimize some modulo operations in Objects/longobject.c. Patch by Jeremiah Vivian.

bpo-46409 [https://bugs.python.org/issue?@action=redirect&bpo=46409]: Add new RETURN_GENERATOR bytecode to make generators. Simplifies calling Python functions in the VM, as they no longer any need to special case generator functions.

Also add JUMP_NO_INTERRUPT bytecode that acts like JUMP_ABSOLUTE, but does not check for interrupts.

bpo-46406 [https://bugs.python.org/issue?@action=redirect&bpo=46406]: The integer division // implementation has been optimized to better let the compiler understand its constraints. It can be 20% faster on the amd64 platform when dividing an int by a value smaller than 2**30.

bpo-46383 [https://bugs.python.org/issue?@action=redirect&bpo=46383]: Fix invalid signature of _zoneinfo’s module_free function to resolve a crash on wasm32-emscripten platform.

bpo-46361 [https://bugs.python.org/issue?@action=redirect&bpo=46361]: Ensure that “small” integers created by int.from_bytes() and decimal.Decimal are properly cached.

bpo-46161 [https://bugs.python.org/issue?@action=redirect&bpo=46161]: Fix the class building error when the arguments are constants and CALL_FUNCTION_EX is used.

bpo-46028 [https://bugs.python.org/issue?@action=redirect&bpo=46028]: Fixes calculation of sys._base_executable when inside a virtual environment that uses symlinks with different binary names than the base environment provides.

bpo-46091 [https://bugs.python.org/issue?@action=redirect&bpo=46091]: Correctly calculate indentation levels for lines with whitespace character that are ended by line continuation characters. Patch by Pablo Galindo

bpo-30512 [https://bugs.python.org/issue?@action=redirect&bpo=30512]: Add CAN Socket support for NetBSD.

bpo-46045 [https://bugs.python.org/issue?@action=redirect&bpo=46045]: Do not use POSIX semaphores on NetBSD

bpo-44024 [https://bugs.python.org/issue?@action=redirect&bpo=44024]: Improve the TypeError message for non-string second arguments passed to the built-in functions getattr() and hasattr(). Patch by Géry Ogam.

Library

bpo-46624 [https://bugs.python.org/issue?@action=redirect&bpo=46624]: Restore support for non-integer arguments of random.randrange() and random.randint().

bpo-46591 [https://bugs.python.org/issue?@action=redirect&bpo=46591]: Make the IDLE doc URL on the About IDLE dialog clickable.

bpo-46565 [https://bugs.python.org/issue?@action=redirect&bpo=46565]: Remove loop variables that are leaking into modules’ namespaces.

bpo-46553 [https://bugs.python.org/issue?@action=redirect&bpo=46553]: In typing.get_type_hints(), support evaluating bare stringified ClassVar annotations. Patch by Gregory Beauregard.

bpo-46544 [https://bugs.python.org/issue?@action=redirect&bpo=46544]: Don’t leak x & uspace intermediate vars in textwrap.TextWrapper.

bpo-46487 [https://bugs.python.org/issue?@action=redirect&bpo=46487]: Add the get_write_buffer_limits method to asyncio.transports.WriteTransport and to the SSL transport.

bpo-45173 [https://bugs.python.org/issue?@action=redirect&bpo=45173]: Note the configparser deprecations will be removed in Python 3.12.

bpo-45162 [https://bugs.python.org/issue?@action=redirect&bpo=45162]: The deprecated unittest APIs removed in 3.11a1 have been temporarily restored to be removed in 3.12 while cleanups in external projects go in.

bpo-46539 [https://bugs.python.org/issue?@action=redirect&bpo=46539]: In typing.get_type_hints(), support evaluating stringified ClassVar and Final annotations inside Annotated. Patch by Gregory Beauregard.

bpo-46510 [https://bugs.python.org/issue?@action=redirect&bpo=46510]: Add missing test for types.TracebackType and types.FrameType. Calculate them directly from the caught exception without calling sys.exc_info().

bpo-46491 [https://bugs.python.org/issue?@action=redirect&bpo=46491]: Allow typing.Annotated to wrap typing.Final and typing.ClassVar. Patch by Gregory Beauregard.

bpo-46483 [https://bugs.python.org/issue?@action=redirect&bpo=46483]: Remove __class_getitem__() from pathlib.PurePath as this class was not supposed to be generic.

bpo-46436 [https://bugs.python.org/issue?@action=redirect&bpo=46436]: Fix command-line option -d/--directory in module http.server which is ignored when combined with command-line option --cgi. Patch by Géry Ogam.

bpo-41403 [https://bugs.python.org/issue?@action=redirect&bpo=41403]: Make mock.patch() raise a TypeError with a relevant error message on invalid arg. Previously it allowed a cryptic AttributeError to escape.

bpo-46474 [https://bugs.python.org/issue?@action=redirect&bpo=46474]: In importlib.metadata.EntryPoint.pattern, avoid potential REDoS by limiting ambiguity in consecutive whitespace.

bpo-46474 [https://bugs.python.org/issue?@action=redirect&bpo=46474]: Removed private method from importlib.metadata.Path. Sync with importlib_metadata 4.10.0.

bpo-46470 [https://bugs.python.org/issue?@action=redirect&bpo=46470]: Remove unused branch from typing._remove_dups_flatten

bpo-46469 [https://bugs.python.org/issue?@action=redirect&bpo=46469]: asyncio generic classes now return types.GenericAlias in __class_getitem__ instead of the same class.

bpo-41906 [https://bugs.python.org/issue?@action=redirect&bpo=41906]: Support passing filter instances in the filters values of handlers and loggers in the dictionary passed to logging.config.dictConfig().

bpo-46422 [https://bugs.python.org/issue?@action=redirect&bpo=46422]: Use dis.Positions in dis.Instruction instead of a regular tuple.

bpo-46434 [https://bugs.python.org/issue?@action=redirect&bpo=46434]: pdb now gracefully handles help when __doc__ is missing, for example when run with pregenerated optimized .pyc files.

bpo-43869 [https://bugs.python.org/issue?@action=redirect&bpo=43869]: Python uses the same time Epoch on all platforms. Add an explicit unit test to ensure that it’s the case. Patch by Victor Stinner.

bpo-46414 [https://bugs.python.org/issue?@action=redirect&bpo=46414]: Add typing.reveal_type(). Patch by Jelle Zijlstra.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: subprocess now imports Windows-specific imports when msvcrt module is available, and POSIX-specific imports on all other platforms. This gives a clean exception when _posixsubprocess is not available (e.g. Emscripten browser target).

bpo-40066 [https://bugs.python.org/issue?@action=redirect&bpo=40066]: IntEnum, IntFlag, and StrEnum use the mixed-in type for their str() and format() output.

bpo-46316 [https://bugs.python.org/issue?@action=redirect&bpo=46316]: Optimize pathlib.Path.iterdir() by removing an unnecessary check for special entries.

bpo-29688 [https://bugs.python.org/issue?@action=redirect&bpo=29688]: Document pathlib.Path.absolute() (which has always existed).

bpo-43012 [https://bugs.python.org/issue?@action=redirect&bpo=43012]: The pathlib module’s obsolete and internal _Accessor class has been removed to prepare the terrain for upcoming enhancements to the module.

bpo-46258 [https://bugs.python.org/issue?@action=redirect&bpo=46258]: Speed up math.isqrt() for small positive integers by replacing two division steps with a lookup table.

bpo-46242 [https://bugs.python.org/issue?@action=redirect&bpo=46242]: Improve error message when creating a new enum.Enum type subclassing an existing Enum with _member_names_ using enum.Enum.__call__().

bpo-43118 [https://bugs.python.org/issue?@action=redirect&bpo=43118]: Fix a bug in inspect.signature() that was causing it to fail on some subclasses of classes with a __text_signature__ referencing module globals. Patch by Weipeng Hong.

bpo-26552 [https://bugs.python.org/issue?@action=redirect&bpo=26552]: Fixed case where failing asyncio.ensure_future() did not close the coroutine. Patch by Kumar Aditya.

bpo-21987 [https://bugs.python.org/issue?@action=redirect&bpo=21987]: Fix an issue with tarfile.TarFile.getmember() getting a directory name with a trailing slash.

bpo-46124 [https://bugs.python.org/issue?@action=redirect&bpo=46124]: Update zoneinfo to rely on importlib.resources traversable API.

bpo-46103 [https://bugs.python.org/issue?@action=redirect&bpo=46103]: Now inspect.getmembers() only gets __bases__ attribute from class type. Patch by Weipeng Hong.

bpo-46080 [https://bugs.python.org/issue?@action=redirect&bpo=46080]: Fix exception in argparse help text generation if a argparse.BooleanOptionalAction argument’s default is argparse.SUPPRESS and it has help specified. Patch by Felix Fontein.

bpo-44791 [https://bugs.python.org/issue?@action=redirect&bpo=44791]: Fix substitution of ParamSpec in Concatenate with different parameter expressions. Substitution with a list of types returns now a tuple of types. Substitution with Concatenate returns now a Concatenate with concatenated lists of arguments.

Documentation

bpo-46463 [https://bugs.python.org/issue?@action=redirect&bpo=46463]: Fixes escape4chm.py script used when building the CHM documentation file

Tests

bpo-43478 [https://bugs.python.org/issue?@action=redirect&bpo=43478]: Mocks can no longer be provided as the specs for other Mocks. As a result, an already-mocked object cannot be passed to mock.Mock(). This can uncover bugs in tests since these Mock-derived Mocks will always pass certain tests (e.g. isinstance) and builtin assert functions (e.g. assert_called_once_with) will unconditionally pass.

bpo-46616 [https://bugs.python.org/issue?@action=redirect&bpo=46616]: Ensures test_importlib.test_windows cleans up registry keys after completion.

bpo-44359 [https://bugs.python.org/issue?@action=redirect&bpo=44359]: test_ftplib now silently ignores socket errors to prevent logging unhandled threading exceptions. Patch by Victor Stinner.

bpo-46600 [https://bugs.python.org/issue?@action=redirect&bpo=46600]: Fix test_gdb.test_pycfunction() for Python built with clang -Og. Tolerate inlined functions in the gdb traceback. Patch by Victor Stinner.

bpo-46542 [https://bugs.python.org/issue?@action=redirect&bpo=46542]: Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. Patch by Victor Stinner.

bpo-46576 [https://bugs.python.org/issue?@action=redirect&bpo=46576]: test_peg_generator now disables compiler optimization when testing compilation of its own C extensions to significantly speed up the testing on non-debug builds of CPython.

bpo-46542 [https://bugs.python.org/issue?@action=redirect&bpo=46542]: Fix test_json tests checking for RecursionError: modify these tests to use support.infinite_recursion(). Patch by Victor Stinner.

bpo-13886 [https://bugs.python.org/issue?@action=redirect&bpo=13886]: Skip test_builtin PTY tests on non-ASCII characters if the readline module is loaded. The readline module changes input() behavior, but test_builtin is not intended to test the readline module. Patch by Victor Stinner.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Add test.support.requires_fork() decorators to mark tests that require a working os.fork().

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Add test.support.requires_subprocess() decorator to mark tests which require working subprocess module or os.spawn*. The wasm32-emscripten platform has no support for processes.

bpo-46126 [https://bugs.python.org/issue?@action=redirect&bpo=46126]: Disable ‘descriptions’ when running tests internally.

Build

bpo-46602 [https://bugs.python.org/issue?@action=redirect&bpo=46602]: Tidied up configure.ac so that conftest.c is truncated rather than appended. This assists in the case where the ‘rm’ of conftest.c fails to happen between tests. Downstream issues such as a clobbered SOABI can result.

bpo-46600 [https://bugs.python.org/issue?@action=redirect&bpo=46600]: Fix the test checking if the C compiler supports -Og option in the ./configure script to also use -Og on clang which supports it. Patch by Victor Stinner.

bpo-38472 [https://bugs.python.org/issue?@action=redirect&bpo=38472]: Fix GCC detection in setup.py when cross-compiling. The C compiler is now run with LC_ALL=C. Previously, the detection failed with a German locale.

bpo-46513 [https://bugs.python.org/issue?@action=redirect&bpo=46513]: configure no longer uses AC_C_CHAR_UNSIGNED macro and pyconfig.h no longer defines reserved symbol __CHAR_UNSIGNED__.

bpo-46471 [https://bugs.python.org/issue?@action=redirect&bpo=46471]: Use global singletons for single byte bytes objects in deepfreeze.

bpo-46443 [https://bugs.python.org/issue?@action=redirect&bpo=46443]: Deepfreeze now uses cached small integers as it saves some space for common small integers.

bpo-46429 [https://bugs.python.org/issue?@action=redirect&bpo=46429]: Merge all deep-frozen files into one for space savings. Patch by Kumar Aditya.

bpo-45569 [https://bugs.python.org/issue?@action=redirect&bpo=45569]: The build now defaults to using 30-bit digits for Python integers. Previously either 15-bit or 30-bit digits would be selected, depending on the platform. 15-bit digits may still be selected using the --enable-big-digits=15 option to the configure script, or by defining PYLONG_BITS_IN_DIGIT in pyconfig.h.

bpo-45925 [https://bugs.python.org/issue?@action=redirect&bpo=45925]: Update Windows installer to use SQLite 3.37.2.

bpo-43112 [https://bugs.python.org/issue?@action=redirect&bpo=43112]: Detect musl libc as a separate SOABI (tagged as linux-musl).

Windows

bpo-33125 [https://bugs.python.org/issue?@action=redirect&bpo=33125]: The traditional EXE/MSI based installer for Windows is now available for ARM64

bpo-46362 [https://bugs.python.org/issue?@action=redirect&bpo=46362]: os.path.abspath(“C:CON”) is now fixed to return “\.CON”, not the same path. The regression was true of all legacy DOS devices such as COM1, LPT1, or NUL.

bpo-44934 [https://bugs.python.org/issue?@action=redirect&bpo=44934]: The installer now offers a command-line only option to add the installation directory to the end of PATH instead of at the start.

macOS

bpo-45925 [https://bugs.python.org/issue?@action=redirect&bpo=45925]: Update macOS installer to SQLite 3.37.2.

IDLE

bpo-45296 [https://bugs.python.org/issue?@action=redirect&bpo=45296]: Clarify close, quit, and exit in IDLE. In the File menu, ‘Close’ and ‘Exit’ are now ‘Close Window’ (the current one) and ‘Exit’ is now ‘Exit IDLE’ (by closing all windows). In Shell, ‘quit()’ and ‘exit()’ mean ‘close Shell’. If there are no other windows, this also exits IDLE.

C API

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the public C API by mistake, it must only be used by Python internally. Use the PyTypeObject.tp_members member instead. Patch by Victor Stinner.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Move _Py_GetAllocatedBlocks() and _PyObject_DebugMallocStats() private functions to the internal C API. Patch by Victor Stinner.

bpo-46433 [https://bugs.python.org/issue?@action=redirect&bpo=46433]: The internal function _PyType_GetModuleByDef now correctly handles inheritance patterns involving static types.

bpo-45459 [https://bugs.python.org/issue?@action=redirect&bpo=45459]: Py_buffer and various Py_buffer related functions are now part of the limited API and stable ABI.

bpo-14916 [https://bugs.python.org/issue?@action=redirect&bpo=14916]: Fixed bug in the tokenizer that prevented PyRun_InteractiveOne from parsing from the provided FD.

Python 3.11.0 alpha 4

Release date: 2022-01-13

Core and Builtins

bpo-46070 [https://bugs.python.org/issue?@action=redirect&bpo=46070]: Py_EndInterpreter() now explicitly untracks all objects currently tracked by the GC. Previously, if an object was used later by another interpreter, calling PyObject_GC_UnTrack() on the object crashed if the previous or the next object of the PyGC_Head structure became a dangling pointer. Patch by Victor Stinner.

bpo-46347 [https://bugs.python.org/issue?@action=redirect&bpo=46347]: Fix memory leak in PyEval_EvalCodeEx.

bpo-46339 [https://bugs.python.org/issue?@action=redirect&bpo=46339]: Fix a crash in the parser when retrieving the error text for multi-line f-strings expressions that do not start in the first line of the string. Patch by Pablo Galindo

bpo-46331 [https://bugs.python.org/issue?@action=redirect&bpo=46331]: Do not set line number of instruction storing doc-string. Fixes regression introduced in 3.11 alpha.

bpo-46314 [https://bugs.python.org/issue?@action=redirect&bpo=46314]: Remove spurious “call” event when creating a lambda function that was accidentally introduced in 3.11a4.

bpo-46289 [https://bugs.python.org/issue?@action=redirect&bpo=46289]: ASDL declaration of FormattedValue has changed to reflect conversion field is not optional.

bpo-46297 [https://bugs.python.org/issue?@action=redirect&bpo=46297]: Fixed an interpreter crash on bootup with multiple PythonPaths set in the Windows registry. Patch by Derzsi Dániel.

bpo-46237 [https://bugs.python.org/issue?@action=redirect&bpo=46237]: Fix the line number of tokenizer errors inside f-strings. Patch by Pablo Galindo.

bpo-46263 [https://bugs.python.org/issue?@action=redirect&bpo=46263]: We always expect the “use_frozen_modules” config to be set, now that getpath.c was rewritten in pure Python and the logic improved.

bpo-46006 [https://bugs.python.org/issue?@action=redirect&bpo=46006]: Fix a regression when a type method like __init__() is modified in a subinterpreter. Fix a regression in _PyUnicode_EqualToASCIIId() and type update_slot(). Revert the change which made the Unicode dictionary of interned strings compatible with subinterpreters: the internal interned dictionary is shared again by all interpreters. Patch by Victor Stinner.

bpo-45923 [https://bugs.python.org/issue?@action=redirect&bpo=45923]: Add RESUME opcode. This is a logical no-op. It is emitted by the compiler anywhere a Python function can be entered. It is used by the interpreter to perform tracing and optimizer checks.

bpo-46208 [https://bugs.python.org/issue?@action=redirect&bpo=46208]: Fix the regression of os.path.normpath(“A/../../B”) not returning expected “../B” but “B”.

bpo-46240 [https://bugs.python.org/issue?@action=redirect&bpo=46240]: Correct the error message for unclosed parentheses when the tokenizer doesn’t reach the end of the source when the error is reported. Patch by Pablo Galindo

bpo-46009 [https://bugs.python.org/issue?@action=redirect&bpo=46009]: Remove the GEN_START opcode.

bpo-46235 [https://bugs.python.org/issue?@action=redirect&bpo=46235]: Certain sequence multiplication operations like [0] * 1_000 are now faster due to reference-counting optimizations. Patch by Dennis Sweeney.

bpo-46221 [https://bugs.python.org/issue?@action=redirect&bpo=46221]: PREP_RERAISE_STAR no longer pushes lasti to the stack.

bpo-46202 [https://bugs.python.org/issue?@action=redirect&bpo=46202]: Remove POP_EXCEPT_AND_RERAISE and replace it by an equivalent sequence of other opcodes.

bpo-46085 [https://bugs.python.org/issue?@action=redirect&bpo=46085]: Fix iterator cache mechanism of OrderedDict.

bpo-46055 [https://bugs.python.org/issue?@action=redirect&bpo=46055]: Speed up shifting operation involving integers less than PyLong_BASE. Patch by Xinhang Xu.

bpo-46110 [https://bugs.python.org/issue?@action=redirect&bpo=46110]: Add a maximum recursion check to the PEG parser to avoid stack overflow. Patch by Pablo Galindo

bpo-46107 [https://bugs.python.org/issue?@action=redirect&bpo=46107]: Fix bug where ExceptionGroup.split() and ExceptionGroup.subgroup() did not copy the exception group’s __note__ field to the parts.

bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711]: The interpreter state’s representation of handled exceptions (a.k.a exc_info, or _PyErr_StackItem) now has only the exc_value field, exc_type and exc_traceback have been removed as their values can be derived from exc_value.

bpo-44525 [https://bugs.python.org/issue?@action=redirect&bpo=44525]: Replace the four call bytecode instructions which one pre-call instruction and two call instructions.

Removes CALL_FUNCTION, CALL_FUNCTION_KW, CALL_METHOD and CALL_METHOD_KW.

Adds CALL_NO_KW and CALL_KW call instructions, and PRECALL_METHOD prefix for pairing with LOAD_METHOD.

bpo-46039 [https://bugs.python.org/issue?@action=redirect&bpo=46039]: Remove the YIELD_FROM instruction and replace it with the SEND instruction which performs the same operation, but without the loop.

bpo-45635 [https://bugs.python.org/issue?@action=redirect&bpo=45635]: The code called from _PyErr_Display() was refactored to improve error handling. It now exits immediately upon an unrecoverable error.

bpo-46054 [https://bugs.python.org/issue?@action=redirect&bpo=46054]: Fix parser error when parsing non-utf8 characters in source files. Patch by Pablo Galindo.

bpo-46042 [https://bugs.python.org/issue?@action=redirect&bpo=46042]: Improve the location of the caret in SyntaxError exceptions emitted by the symbol table. Patch by Pablo Galindo.

bpo-46049 [https://bugs.python.org/issue?@action=redirect&bpo=46049]: Ensure ._pth files work as intended on platforms other than Windows.

bpo-46048 [https://bugs.python.org/issue?@action=redirect&bpo=46048]: Fixes parsing of ._pth files on startup so that single-character paths are correctly read.

bpo-37971 [https://bugs.python.org/issue?@action=redirect&bpo=37971]: Fix a bug where the line numbers given in a traceback when a decorator application raised an exception were wrong.

bpo-46031 [https://bugs.python.org/issue?@action=redirect&bpo=46031]: Add POP_JUMP_IF_NOT_NONE and POP_JUMP_IF_NONE opcodes to speed up conditional jumps.

bpo-45654 [https://bugs.python.org/issue?@action=redirect&bpo=45654]: Deepfreeze runpy, patch by Kumar Aditya.

bpo-46025 [https://bugs.python.org/issue?@action=redirect&bpo=46025]: Fix a crash in the atexit module involving functions that unregister themselves before raising exceptions. Patch by Pablo Galindo.

bpo-46000 [https://bugs.python.org/issue?@action=redirect&bpo=46000]: Improve compatibility of the curses module with NetBSD curses.

bpo-44525 [https://bugs.python.org/issue?@action=redirect&bpo=44525]: Specialize the CALL_FUNCTION instruction for calls to builtin types with a single argument. Speeds up range(x), list(x), and specifically type(obj).

bpo-42918 [https://bugs.python.org/issue?@action=redirect&bpo=42918]: Fix bug where the built-in compile() function did not always raise a SyntaxError when passed multiple statements in ‘single’ mode. Patch by Weipeng Hong.

bpo-45953 [https://bugs.python.org/issue?@action=redirect&bpo=45953]: The main interpreter in _PyRuntimeState.interpreters is now statically allocated (as part of _PyRuntime). Likewise for the initial thread state of each interpreter. This means less allocation during runtime init, as well as better memory locality for these key state objects.

bpo-45292 [https://bugs.python.org/issue?@action=redirect&bpo=45292]: Complete the PEP 654 [https://peps.python.org/pep-0654/] implementation: add except*.

bpo-43413 [https://bugs.python.org/issue?@action=redirect&bpo=43413]: Revert changes in set.__init__. Subclass of set needs to define a __init__() method if it defines a __new__() method with additional keyword parameters.

bpo-43931 [https://bugs.python.org/issue?@action=redirect&bpo=43931]: Added the Py_Version constant which bears the same value as PY_VERSION_HEX. Patch by Gabriele N. Tornetta.

Library

bpo-46342 [https://bugs.python.org/issue?@action=redirect&bpo=46342]: The @typing.final decorator now sets the __final__ attribute on the decorated object to allow runtime introspection. Patch by Jelle Zijlstra.

bpo-46328 [https://bugs.python.org/issue?@action=redirect&bpo=46328]: Added the sys.exception() method which returns the active exception instance.

bpo-46307 [https://bugs.python.org/issue?@action=redirect&bpo=46307]: Add string.Template.is_valid() and string.Template.get_identifiers() methods.

bpo-46306 [https://bugs.python.org/issue?@action=redirect&bpo=46306]: Assume that types.CodeType always has types.CodeType.co_firstlineno in doctest.

bpo-40479 [https://bugs.python.org/issue?@action=redirect&bpo=40479]: Fix hashlib usedforsecurity option to work correctly with OpenSSL 3.0.0 in FIPS mode.

bpo-46070 [https://bugs.python.org/issue?@action=redirect&bpo=46070]: Fix possible segfault when importing the asyncio module from different sub-interpreters in parallel. Patch by Erlend E. Aasland.

bpo-46244 [https://bugs.python.org/issue?@action=redirect&bpo=46244]: Removed __slots__ from typing.ParamSpec and typing.TypeVar. They served no purpose. Patch by Arie Bovenberg.

bpo-46278 [https://bugs.python.org/issue?@action=redirect&bpo=46278]: Reflect context argument in AbstractEventLoop.call_*() methods. Loop implementations already support it.

bpo-46269 [https://bugs.python.org/issue?@action=redirect&bpo=46269]: Remove special-casing of __new__ in enum.Enum.__dir__().

bpo-46266 [https://bugs.python.org/issue?@action=redirect&bpo=46266]: Improve day constants in calendar.

Now all constants (MONDAY … SUNDAY) are documented, tested, and added to __all__.

bpo-46257 [https://bugs.python.org/issue?@action=redirect&bpo=46257]: Optimized the mean, variance, and stdev functions in the statistics module. If the input is an iterator, it is consumed in a single pass rather than eating memory by conversion to a list. The single pass algorithm is about twice as fast as the previous two pass code.

bpo-41011 [https://bugs.python.org/issue?@action=redirect&bpo=41011]: Added two new variables to pyvenv.cfg which is generated by venv module: executable for the executable and command for the command line used to create the environment.

bpo-46239 [https://bugs.python.org/issue?@action=redirect&bpo=46239]: Improve error message when importing asyncio.windows_events on non-Windows.

bpo-46238 [https://bugs.python.org/issue?@action=redirect&bpo=46238]: Reuse _winapi constants in asyncio.windows_events.

bpo-46222 [https://bugs.python.org/issue?@action=redirect&bpo=46222]: Adding SF_NOCACHE sendfile constant for FreeBSD for the posixmodule.

bpo-37295 [https://bugs.python.org/issue?@action=redirect&bpo=37295]: Add fast path for 0 <= k <= n <= 67 for math.comb().

bpo-46176 [https://bugs.python.org/issue?@action=redirect&bpo=46176]: Adding the MAP_STACK constant for the mmap module.

bpo-43424 [https://bugs.python.org/issue?@action=redirect&bpo=43424]: Deprecate webbrowser.MacOSXOSAScript._name and use name instead.

bpo-45321 [https://bugs.python.org/issue?@action=redirect&bpo=45321]: Added missing error codes to module xml.parsers.expat.errors.

bpo-46125 [https://bugs.python.org/issue?@action=redirect&bpo=46125]: Refactor tests to test traversable API directly. Includes changes from importlib 5.4.0.

bpo-46118 [https://bugs.python.org/issue?@action=redirect&bpo=46118]: Moved importlib.resources and its related functionality to a package.

bpo-37578 [https://bugs.python.org/issue?@action=redirect&bpo=37578]: Add include_hidden parameter to glob() and iglob() to match hidden files and directories when using special characters like *, **, ? and [].

bpo-20369 [https://bugs.python.org/issue?@action=redirect&bpo=20369]: concurrent.futures.wait() no longer blocks forever when given duplicate Futures. Patch by Kumar Aditya.

bpo-46105 [https://bugs.python.org/issue?@action=redirect&bpo=46105]: Honor spec when generating requirement specs with urls and extras (importlib_metadata 4.8.3).

bpo-44893 [https://bugs.python.org/issue?@action=redirect&bpo=44893]: EntryPoint objects are no longer tuples. Recommended means to access is by attribute (‘.name’, ‘.group’) or accessor (‘.load()’). Access by index is deprecated and will raise deprecation warning.

bpo-22815 [https://bugs.python.org/issue?@action=redirect&bpo=22815]: Print unexpected successes together with failures and errors in summary in unittest.TextTestResult.

bpo-22047 [https://bugs.python.org/issue?@action=redirect&bpo=22047]: Calling add_argument_group() on an argument group is deprecated. Calling add_argument_group() or add_mutually_exclusive_group() on a mutually exclusive group is deprecated.

These features were never supported and do not always work correctly. The functions exist on the API by accident through inheritance and will be removed in the future.

bpo-26952 [https://bugs.python.org/issue?@action=redirect&bpo=26952]: argparse raises ValueError with clear message when trying to render usage for an empty mutually exclusive group. Previously it raised a cryptic IndexError.

bpo-45615 [https://bugs.python.org/issue?@action=redirect&bpo=45615]: Functions in the traceback module raise TypeError rather than AttributeError when an exception argument is not of type BaseException.

bpo-16594 [https://bugs.python.org/issue?@action=redirect&bpo=16594]: Add allow allow_reuse_port flag in socketserver.

bpo-27718 [https://bugs.python.org/issue?@action=redirect&bpo=27718]: Fix help for the signal module. Some functions (e.g. signal() and getsignal()) were omitted.

bpo-46032 [https://bugs.python.org/issue?@action=redirect&bpo=46032]: The registry() method of functools.singledispatch() functions checks now the first argument or the first parameter annotation and raises a TypeError if it is not supported. Previously unsupported “types” were ignored (e.g. typing.List[int]) or caused an error at calling time (e.g. list[int]).

bpo-46014 [https://bugs.python.org/issue?@action=redirect&bpo=46014]: Add ability to use typing.Union and types.UnionType as dispatch argument to functools.singledispatch. Patch provided by Yurii Karabas.

bpo-27062 [https://bugs.python.org/issue?@action=redirect&bpo=27062]: Add __all__ to inspect, patch by Kumar Aditya.

bpo-46018 [https://bugs.python.org/issue?@action=redirect&bpo=46018]: Ensure that math.expm1() does not raise on underflow.

bpo-46016 [https://bugs.python.org/issue?@action=redirect&bpo=46016]: Adding F_DUP2FD and F_DUP2FD_CLOEXEC constants from FreeBSD into the fcntl module.

bpo-45755 [https://bugs.python.org/issue?@action=redirect&bpo=45755]: typing generic aliases now reveal the class attributes of the original generic class when passed to dir(). This was the behavior up to Python 3.6, but was changed in 3.7-3.9.

bpo-45874 [https://bugs.python.org/issue?@action=redirect&bpo=45874]: The empty query string, consisting of no query arguments, is now handled correctly in urllib.parse.parse_qsl. This caused problems before when strict parsing was enabled.

bpo-44674 [https://bugs.python.org/issue?@action=redirect&bpo=44674]: Change how dataclasses disallows mutable default values. It used to use a list of known types (list, dict, set). Now it disallows unhashable objects to be defaults. It’s using unhashability as a proxy for mutability. Patch by Eric V. Smith, idea by Raymond Hettinger.

bpo-23882 [https://bugs.python.org/issue?@action=redirect&bpo=23882]: Remove namespace package (PEP 420) support from unittest discovery. It was introduced in Python 3.4 but has been broken since Python 3.7.

bpo-25066 [https://bugs.python.org/issue?@action=redirect&bpo=25066]: Added a __repr__() method to multiprocessing.Event objects, patch by Kumar Aditya.

bpo-45643 [https://bugs.python.org/issue?@action=redirect&bpo=45643]: Added signal.SIGSTKFLT on platforms where this signal is defined.

bpo-44092 [https://bugs.python.org/issue?@action=redirect&bpo=44092]: Fetch across rollback no longer raises InterfaceError. Instead we leave it to the SQLite library to handle these cases. Patch by Erlend E. Aasland.

bpo-42413 [https://bugs.python.org/issue?@action=redirect&bpo=42413]: Replace concurrent.futures.TimeoutError and asyncio.TimeoutError with builtin TimeoutError, keep these names as deprecated aliases.

Documentation

bpo-46196 [https://bugs.python.org/issue?@action=redirect&bpo=46196]: Document method cmd.Cmd.columnize().

bpo-46120 [https://bugs.python.org/issue?@action=redirect&bpo=46120]: State that | is preferred for readability over Union in the typing docs.

bpo-46109 [https://bugs.python.org/issue?@action=redirect&bpo=46109]: Extracted importlib.resources and importlib.resources.abc documentation into separate files.

bpo-19737 [https://bugs.python.org/issue?@action=redirect&bpo=19737]: Update the documentation for the globals() function.

Tests

bpo-46296 [https://bugs.python.org/issue?@action=redirect&bpo=46296]: Add a test case for enum with _use_args_ == True and _member_type_ == object.

bpo-46205 [https://bugs.python.org/issue?@action=redirect&bpo=46205]: Fix hang in runtest_mp due to race condition

bpo-46263 [https://bugs.python.org/issue?@action=redirect&bpo=46263]: Fix test_capi on FreeBSD 14-dev: instruct jemalloc to not fill freed memory with junk byte.

bpo-46262 [https://bugs.python.org/issue?@action=redirect&bpo=46262]: Cover ValueError path in tests for enum.Flag._missing_().

bpo-46150 [https://bugs.python.org/issue?@action=redirect&bpo=46150]: Now fakename in test_pathlib.PosixPathTest.test_expanduser is checked to be non-existent.

bpo-46129 [https://bugs.python.org/issue?@action=redirect&bpo=46129]: Rewrite asyncio.locks tests with unittest.IsolatedAsyncioTestCase usage.

bpo-23819 [https://bugs.python.org/issue?@action=redirect&bpo=23819]: Fixed asyncio tests in python optimized mode. Patch by Kumar Aditya.

bpo-46114 [https://bugs.python.org/issue?@action=redirect&bpo=46114]: Fix test case for OpenSSL 3.0.1 version. OpenSSL 3.0 uses 0xMNN00PP0L.

Build

bpo-44133 [https://bugs.python.org/issue?@action=redirect&bpo=44133]: When Python is configured with --without-static-libpython, the Python static library (libpython.a) is no longer built. Patch by Victor Stinner.

bpo-44133 [https://bugs.python.org/issue?@action=redirect&bpo=44133]: When Python is built without --enable-shared, the python program is now linked to object files, rather than being linked to the Python static library (libpython.a), to make sure that all symbols are exported. Previously, the linker omitted some symbols like the Py_FrozenMain() function. Patch by Victor Stinner.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: The configure script has a new option --with-emscripten-target to select browser or node as Emscripten build target.

bpo-46315 [https://bugs.python.org/issue?@action=redirect&bpo=46315]: Added and fixed #ifdef HAVE_FEATURE checks for functionality that is not available on WASI platform.

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: Fixed a regression in configure check for select.epoll().

bpo-46263 [https://bugs.python.org/issue?@action=redirect&bpo=46263]: configure no longer sets MULTIARCH on FreeBSD platforms.

bpo-46106 [https://bugs.python.org/issue?@action=redirect&bpo=46106]: Updated OpenSSL to 1.1.1m in Windows builds, macOS installer builds, and CI. Patch by Kumar Aditya.

bpo-46088 [https://bugs.python.org/issue?@action=redirect&bpo=46088]: Automatically detect or install bootstrap Python runtime when building from Visual Studio.

bpo-46072 [https://bugs.python.org/issue?@action=redirect&bpo=46072]: Add a –with-pystats configure option to turn on internal statistics gathering.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: A new directory Tools/wasm contains WebAssembly-related helpers like config.site override for wasm32-emscripten, wasm assets generator to bundle the stdlib, and a README.

bpo-46023 [https://bugs.python.org/issue?@action=redirect&bpo=46023]: makesetup no longer builds extensions that have been marked as disabled. This allows users to disable modules in Modules/Setup.local.

bpo-45949 [https://bugs.python.org/issue?@action=redirect&bpo=45949]: Use pure Python freeze_module for all but importlib bootstrap files. --with-freeze-module configure option is no longer needed for cross builds.

Windows

bpo-46217 [https://bugs.python.org/issue?@action=redirect&bpo=46217]: Removed parameter that is unsupported on Windows 8.1 and early Windows 10 and may have caused build or runtime failures.

macOS

bpo-40477 [https://bugs.python.org/issue?@action=redirect&bpo=40477]: The Python Launcher app for macOS now properly launches scripts and, if necessary, the Terminal app when running on recent macOS releases.

C API

bpo-46236 [https://bugs.python.org/issue?@action=redirect&bpo=46236]: Fix a bug in PyFunction_GetAnnotations() that caused it to return a tuple instead of a dict.

bpo-46140 [https://bugs.python.org/issue?@action=redirect&bpo=46140]: PyBuffer_GetPointer(), PyBuffer_FromContiguous(), PyBuffer_ToContiguous() and PyMemoryView_FromBuffer() now take buffer info by const Py_buffer * instead of Py_buffer *, as they do not need mutability. PyBuffer_FromContiguous() also now takes the source buffer as const void *, and similarly PyBuffer_GetPointer() takes the strides as const Py_ssize_t *.

bpo-45855 [https://bugs.python.org/issue?@action=redirect&bpo=45855]: Document that the no_block argument to PyCapsule_Import() is a no-op now.

bpo-45855 [https://bugs.python.org/issue?@action=redirect&bpo=45855]: Replaced deprecated usage of PyImport_ImportModuleNoBlock() with PyImport_ImportModule() in stdlib modules. Patch by Kumar Aditya.

bpo-46007 [https://bugs.python.org/issue?@action=redirect&bpo=46007]: The PyUnicode_CHECK_INTERNED() macro has been excluded from the limited C API. It was never usable there, because it used internal structures which are not available in the limited C API. Patch by Victor Stinner.

Python 3.11.0 alpha 3

Release date: 2021-12-08

Core and Builtins

bpo-46009 [https://bugs.python.org/issue?@action=redirect&bpo=46009]: Restore behavior from 3.9 and earlier when sending non-None to newly started generator. In 3.9 this did not affect the state of the generator. In 3.10.0 and 3.10.1 gen_func().send(0) is equivalent to gen_func().throw(TypeError(...) which exhausts the generator. In 3.10.2 onward, the behavior has been reverted to that of 3.9.

bpo-46004 [https://bugs.python.org/issue?@action=redirect&bpo=46004]: Fix the SyntaxError location for errors involving for loops with invalid targets. Patch by Pablo Galindo

bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711]: _PyErr_ChainStackItem() no longer normalizes exc_info (including setting the traceback on the exception instance) because exc_info is always normalized.

bpo-45607 [https://bugs.python.org/issue?@action=redirect&bpo=45607]: The __note__ field was added to BaseException. It is None by default but can be set to a string which is added to the exception’s traceback.

bpo-45947 [https://bugs.python.org/issue?@action=redirect&bpo=45947]: Place pointers to dict and values immediately before GC header. This reduces number of dependent memory loads to access either dict or values from 3 to 1.

bpo-45915 [https://bugs.python.org/issue?@action=redirect&bpo=45915]: is_valid_fd now uses faster fcntl(fd, F_GETFD) on Linux, macOS, and Windows.

bpo-44530 [https://bugs.python.org/issue?@action=redirect&bpo=44530]: Reverts a change to the code.__new__ audit event from an earlier prerelease.

bpo-42268 [https://bugs.python.org/issue?@action=redirect&bpo=42268]: Fail the configure step if the selected compiler doesn’t support memory sanitizer. Patch by Pablo Galindo

bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711]: The three values of exc_info are now always consistent with each other. In particular, the type and traceback fields are now derived from the exception instance. This impacts the return values of sys.exc_info() and PyErr_GetExcInfo() if the exception instance is modified while the exception is handled, as well as PyErr_SetExcInfo(), which now ignores the type and traceback arguments provided to it.

bpo-45727 [https://bugs.python.org/issue?@action=redirect&bpo=45727]: Refine the custom syntax error that suggests that a comma may be missing to trigger only when the expressions are detected between parentheses or brackets. Patch by Pablo Galindo

bpo-45885 [https://bugs.python.org/issue?@action=redirect&bpo=45885]: Specialized the COMPARE_OP opcode using the PEP 659 machinery.

bpo-45786 [https://bugs.python.org/issue?@action=redirect&bpo=45786]: Allocate space for the interpreter frame in the frame object, to avoid an additional allocation when the frame object outlives the frame activation.

bpo-45614 [https://bugs.python.org/issue?@action=redirect&bpo=45614]: Fix traceback display for exceptions with invalid module name.

bpo-45813 [https://bugs.python.org/issue?@action=redirect&bpo=45813]: Fix crash when calling coro.cr_frame.clear() after coroutine has been freed.

bpo-45811 [https://bugs.python.org/issue?@action=redirect&bpo=45811]: Improve the tokenizer errors when encountering invisible control characters in the parser. Patch by Pablo Galindo

bpo-45848 [https://bugs.python.org/issue?@action=redirect&bpo=45848]: Allow the parser to obtain error lines directly from encoded files. Patch by Pablo Galindo

bpo-45709 [https://bugs.python.org/issue?@action=redirect&bpo=45709]: Restore behavior from 3.10 when tracing an exception raised within a with statement.

bpo-44525 [https://bugs.python.org/issue?@action=redirect&bpo=44525]: Adds new COPY_FREE_VARS opcode, to make copying of free variables from function to frame explicit. Helps optimization of calls to Python function.

bpo-45829 [https://bugs.python.org/issue?@action=redirect&bpo=45829]: Specialize BINARY_SUBSCR for classes with a __getitem__ method implemented in Python

bpo-45826 [https://bugs.python.org/issue?@action=redirect&bpo=45826]: Fixed a crash when calling .with_traceback(None) on NameError. This occurs internally in unittest.TestCase.assertRaises().

bpo-45822 [https://bugs.python.org/issue?@action=redirect&bpo=45822]: Fixed a bug in the parser that was causing it to not respect PEP 263 [https://peps.python.org/pep-0263/] coding cookies when no flags are provided. Patch by Pablo Galindo

bpo-45820 [https://bugs.python.org/issue?@action=redirect&bpo=45820]: Fix a segfault when the parser fails without reading any input. Patch by Pablo Galindo

bpo-45636 [https://bugs.python.org/issue?@action=redirect&bpo=45636]: Simplify the implementation of BINARY_OP by indexing into an array of function pointers (rather than switching on the oparg).

bpo-42540 [https://bugs.python.org/issue?@action=redirect&bpo=42540]: Fix crash when os.fork() is called with an active non-default memory allocator.

bpo-45738 [https://bugs.python.org/issue?@action=redirect&bpo=45738]: Fix computation of error location for invalid continuation characters in the parser. Patch by Pablo Galindo.

bpo-45636 [https://bugs.python.org/issue?@action=redirect&bpo=45636]: Remove an existing “fast path” for old-style string formatting, since it no longer appears to have any measurable impact.

bpo-45753 [https://bugs.python.org/issue?@action=redirect&bpo=45753]: Make recursion checks a bit more efficient by tracking amount of calls left before overflow.

bpo-45773 [https://bugs.python.org/issue?@action=redirect&bpo=45773]: Fix a compiler hang when attempting to optimize certain jump patterns.

bpo-45764 [https://bugs.python.org/issue?@action=redirect&bpo=45764]: The parser now gives a better error message when leaving out the opening parenthesis ( after a def-statement:

>>> def f:
  File "<stdin>", line 1
    def f:
         ^
SyntaxError: expected '('

bpo-45609 [https://bugs.python.org/issue?@action=redirect&bpo=45609]: Specialized the STORE_SUBSCR opcode using the PEP 659 machinery.

bpo-45636 [https://bugs.python.org/issue?@action=redirect&bpo=45636]: Replace all numeric BINARY_* and INPLACE_* instructions with a single BINARY_OP implementation.

bpo-45582 [https://bugs.python.org/issue?@action=redirect&bpo=45582]: Path calculation (known as getpath) has been reimplemented as a frozen Python module. This should have no visible impact, but may affect calculation of all paths referenced in sys and sysconfig.

bpo-45450 [https://bugs.python.org/issue?@action=redirect&bpo=45450]: Improve the syntax error message for parenthesized arguments. Patch by Pablo Galindo.

Library

bpo-27946 [https://bugs.python.org/issue?@action=redirect&bpo=27946]: Fix possible crash when getting an attribute of xml.etree.ElementTree.Element simultaneously with replacing the attrib dict.

bpo-45711 [https://bugs.python.org/issue?@action=redirect&bpo=45711]: Make asyncio normalize exceptions as soon as they are captured with PyErr_Fetch(), and before they are stored as an exc_info triplet. This brings asyncio in line with the rest of the codebase, where an exc_info triplet is always normalized.

bpo-23819 [https://bugs.python.org/issue?@action=redirect&bpo=23819]: Replaced asserts with exceptions in asyncio, patch by Kumar Aditya.

bpo-13236 [https://bugs.python.org/issue?@action=redirect&bpo=13236]: unittest.TextTestResult and unittest.TextTestRunner flush now the output stream more often.

bpo-45917 [https://bugs.python.org/issue?@action=redirect&bpo=45917]: Added math.exp2():, which returns 2 raised to the power of x.

bpo-37658 [https://bugs.python.org/issue?@action=redirect&bpo=37658]: Fix issue when on certain conditions asyncio.wait_for() may allow a coroutine to complete successfully, but fail to return the result, potentially causing memory leaks or other issues.

bpo-45876 [https://bugs.python.org/issue?@action=redirect&bpo=45876]: Improve the accuracy of stdev() and pstdev() in the statistics module. When the inputs are floats or fractions, the output is a correctly rounded float

bpo-44649 [https://bugs.python.org/issue?@action=redirect&bpo=44649]: Handle dataclass(slots=True) with a field that has default a default value, but for which init=False.

bpo-45803 [https://bugs.python.org/issue?@action=redirect&bpo=45803]: Added missing kw_only parameter to dataclasses.make_dataclass().

bpo-45837 [https://bugs.python.org/issue?@action=redirect&bpo=45837]: The turtle.RawTurtle.settiltangle() is deprecated since Python 3.1, it now emits a deprecation warning and will be removed in Python 3.13.

Use turtle.RawTurtle.tiltangle() instead.

turtle.RawTurtle.tiltangle() was earlier incorrectly marked as deprecated, its docstring has been corrected.

Patch by Hugo van Kemenade.

bpo-45831 [https://bugs.python.org/issue?@action=redirect&bpo=45831]: faulthandler can now write ASCII-only strings (like filenames and function names) with a single write() syscall when dumping a traceback. It reduces the risk of getting an unreadable dump when two threads or two processes dump a traceback to the same file (like stderr) at the same time. Patch by Victor Stinner.

bpo-45828 [https://bugs.python.org/issue?@action=redirect&bpo=45828]: sqlite C callbacks now use unraisable exceptions if callback tracebacks are enabled. Patch by Erlend E. Aasland.

bpo-41735 [https://bugs.python.org/issue?@action=redirect&bpo=41735]: Fix thread lock in zlib.Decompress.flush() method before PyObject_GetBuffer.

bpo-45235 [https://bugs.python.org/issue?@action=redirect&bpo=45235]: Reverted an argparse bugfix that caused regression in the handling of default arguments for subparsers. This prevented leaf level arguments from taking precedence over root level arguments.

bpo-45754 [https://bugs.python.org/issue?@action=redirect&bpo=45754]: Fix a regression in Python 3.11a1 and 3.11a2 where sqlite3 incorrectly would use SQLITE_LIMIT_LENGTH when checking SQL statement lengths. Now, SQLITE_LIMIT_SQL_LENGTH is used. Patch by Erlend E. Aasland.

bpo-45766 [https://bugs.python.org/issue?@action=redirect&bpo=45766]: Added proportional option to statistics.linear_regression().

bpo-45765 [https://bugs.python.org/issue?@action=redirect&bpo=45765]: In importlib.metadata, fix distribution discovery for an empty path.

bpo-45757 [https://bugs.python.org/issue?@action=redirect&bpo=45757]: Fix bug where dis produced an incorrect oparg when EXTENDED_ARG is followed by an opcode that does not use its argument.

bpo-45644 [https://bugs.python.org/issue?@action=redirect&bpo=45644]: In-place JSON file formatting using python3 -m json.tool infile infile now works correctly, previously it left the file empty. Patch by Chris Wesseling.

bpo-45703 [https://bugs.python.org/issue?@action=redirect&bpo=45703]: When a namespace package is imported before another module from the same namespace is created/installed in a different sys.path location while the program is running, calling the importlib.invalidate_caches() function will now also guarantee the new module is noticed.

bpo-45535 [https://bugs.python.org/issue?@action=redirect&bpo=45535]: Improve output of dir() with Enums.

bpo-45664 [https://bugs.python.org/issue?@action=redirect&bpo=45664]: Fix types.resolve_bases() and types.new_class() for types.GenericAlias instance as a base.

bpo-45663 [https://bugs.python.org/issue?@action=redirect&bpo=45663]: Fix dataclasses.is_dataclass() for dataclasses which are subclasses of types.GenericAlias.

bpo-45662 [https://bugs.python.org/issue?@action=redirect&bpo=45662]: Fix the repr of dataclasses.InitVar with a type alias to the built-in class, e.g. InitVar[list[int]].

bpo-43137 [https://bugs.python.org/issue?@action=redirect&bpo=43137]: Launch GNOME web browsers via gio tool instead of obsolete gvfs-open

bpo-45429 [https://bugs.python.org/issue?@action=redirect&bpo=45429]: On Windows, time.sleep() now uses a waitable timer which supports high-resolution timers. Patch by Donghee Na and Eryk Sun.

bpo-37295 [https://bugs.python.org/issue?@action=redirect&bpo=37295]: Optimize math.comb() and math.perm().

bpo-45514 [https://bugs.python.org/issue?@action=redirect&bpo=45514]: Deprecated legacy functions in importlib.resources.

bpo-45507 [https://bugs.python.org/issue?@action=redirect&bpo=45507]: Add tests for truncated/missing trailers in gzip.decompress implementation.

bpo-45359 [https://bugs.python.org/issue?@action=redirect&bpo=45359]: Implement PEP 585 [https://peps.python.org/pep-0585/] for graphlib.TopologicalSorter.

bpo-44733 [https://bugs.python.org/issue?@action=redirect&bpo=44733]: Add max_tasks_per_child to concurrent.futures.ProcessPoolExecutor. This allows users to specify the maximum number of tasks a single process should execute before the process needs to be restarted.

bpo-28806 [https://bugs.python.org/issue?@action=redirect&bpo=28806]: Improve netrc library. netrc file no longer needs to contain all tokens. And if the login name is anonymous, security check is no longer need.

bpo-43498 [https://bugs.python.org/issue?@action=redirect&bpo=43498]: Avoid a possible “RuntimeError: dictionary changed size during iteration” when adjusting the process count of ProcessPoolExecutor.

bpo-42158 [https://bugs.python.org/issue?@action=redirect&bpo=42158]: Add MIME types for N-quads, N-triples, Notation3 and TriG to mimetypes.

bpo-30533 [https://bugs.python.org/issue?@action=redirect&bpo=30533]: Add inspect.getmembers_static() , it return all members without triggering dynamic lookup via the descriptor protocol. Patch by Weipeng Hong.

Documentation

bpo-42238 [https://bugs.python.org/issue?@action=redirect&bpo=42238]: make -C Doc suspicious will be removed soon in favor of make -C Doc check, mark it as deprecated.

bpo-45840 [https://bugs.python.org/issue?@action=redirect&bpo=45840]: Improve cross-references in the documentation for the data model.

bpo-45640 [https://bugs.python.org/issue?@action=redirect&bpo=45640]: Properly marked-up grammar tokens in the documentation are now clickable and take you to the definition of a given piece of grammar. Patch by Arthur Milchior.

bpo-45788 [https://bugs.python.org/issue?@action=redirect&bpo=45788]: Link doc for sys.prefix to sysconfig doc on installation paths.

bpo-45772 [https://bugs.python.org/issue?@action=redirect&bpo=45772]: socket.socket documentation is corrected to a class from a function.

bpo-45392 [https://bugs.python.org/issue?@action=redirect&bpo=45392]: Update the docstring of the type built-in to remove a redundant line and to mention keyword arguments for the constructor.

bpo-45250 [https://bugs.python.org/issue?@action=redirect&bpo=45250]: Update the documentation to note that CPython does not consistently require iterators to define __iter__.

bpo-25381 [https://bugs.python.org/issue?@action=redirect&bpo=25381]: In the extending chapter of the extending doc, update a paragraph about the global variables containing exception information.

bpo-43905 [https://bugs.python.org/issue?@action=redirect&bpo=43905]: Expanded astuple() and asdict() docs, warning about deepcopy being applied and providing a workaround.

Tests

bpo-45695 [https://bugs.python.org/issue?@action=redirect&bpo=45695]: Out-of-tree builds with a read-only source directory are now tested by CI.

bpo-19460 [https://bugs.python.org/issue?@action=redirect&bpo=19460]: Add new Test for Lib/email/mime/nonmultipart.py::MIMENonMultipart.

bpo-45835 [https://bugs.python.org/issue?@action=redirect&bpo=45835]: Fix race condition in test_queue tests with multiple “feeder” threads.

bpo-45783 [https://bugs.python.org/issue?@action=redirect&bpo=45783]: The test for the freeze tool now handles file moves and deletions.

bpo-45745 [https://bugs.python.org/issue?@action=redirect&bpo=45745]: Remove the --findleaks command line option of regrtest: use the --fail-env-changed option instead. Since Python 3.7, it was a deprecated alias to the --fail-env-changed option.

bpo-45701 [https://bugs.python.org/issue?@action=redirect&bpo=45701]: Add tests with tuple type with functools.lru_cache() to test_functools.

Build

bpo-44035 [https://bugs.python.org/issue?@action=redirect&bpo=44035]: CI now verifies that autoconf files have been regenerated with a current and unpatched autoconf package.

bpo-45950 [https://bugs.python.org/issue?@action=redirect&bpo=45950]: The build system now uses a _bootstrap_python interpreter for freezing and deepfreezing again. To speed up build process the build tools _bootstrap_python and _freeze_module are no longer build with LTO.

bpo-45881 [https://bugs.python.org/issue?@action=redirect&bpo=45881]: The configure script now accepts --with-build-python and --with-freeze-module options to make cross compiling easier.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Emscripten platform now uses .wasm suffix by default.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: Disable unusable core extension modules on WASM/Emscripten targets.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: configure now checks for socket shutdown function. The check makes it possible to disable SYS_shutdown with ac_cv_func_shutdown=no in CONFIG_SITE.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: configure now checks for functions fork1, getegid, geteuid, getgid, getppid, getuid, opendir, pipe, system, wait, ttyname.

bpo-33393 [https://bugs.python.org/issue?@action=redirect&bpo=33393]: Update config.guess to 2021-06-03 and config.sub to 2021-08-14. Makefile now has an update-config target to make updating more convenient.

bpo-45866 [https://bugs.python.org/issue?@action=redirect&bpo=45866]: make regen-all now produces the same output when run from a directory other than the source tree: when building Python out of the source tree. pegen now strips directory of the “generated by pygen from <FILENAME>” header Patch by Victor Stinner.

bpo-40280 [https://bugs.python.org/issue?@action=redirect&bpo=40280]: configure now accepts machine wasm32 or wasm64 and OS wasi or emscripten for cross building, e.g. wasm32-unknown-emscripten, wasm32-wasi, or wasm32-unknown-wasi.

bpo-41498 [https://bugs.python.org/issue?@action=redirect&bpo=41498]: Python now compiles on platforms without sigset_t. Several functions in signal are not available when sigset_t is missing.

Based on patch by Roman Yurchak for pyodide.

bpo-45881 [https://bugs.python.org/issue?@action=redirect&bpo=45881]: setup.py now uses CC from environment first to discover multiarch and cross compile paths.

bpo-45886 [https://bugs.python.org/issue?@action=redirect&bpo=45886]: The _freeze_module program path can now be overridden on the command line, e.g. make FREEZE_MODULE=../x86_64/Program/_freeze_module.

bpo-45873 [https://bugs.python.org/issue?@action=redirect&bpo=45873]: Get rid of the _bootstrap_python build step. The deepfreeze.py script is now run using $(PYTHON_FOR_REGEN) which can be Python 3.7 or newer (on Windows, 3.8 or newer).

bpo-45847 [https://bugs.python.org/issue?@action=redirect&bpo=45847]: Port builtin hashlib extensions to PY_STDLIB_MOD macro and addext().

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: Add autoconf helpers for saving and restoring environment variables:

SAVE_ENV: Save $CFLAGS, $LDFLAGS, $LIBS, and $CPPFLAGS.

RESTORE_ENV: Restore $CFLAGS, $LDFLAGS, $LIBS, and $CPPFLAGS.

WITH_SAVE_ENV([SCRIPT]): Run SCRIPT wrapped with SAVE_ENV and RESTORE_ENV.

Patch by Erlend E. Aasland.

bpo-45573 [https://bugs.python.org/issue?@action=redirect&bpo=45573]: Mandatory core modules, that are required to bootstrap Python, are now in Modules/Setup.bootstrap.

bpo-45573 [https://bugs.python.org/issue?@action=redirect&bpo=45573]: configure now creates Modules/Setup.stdlib with conditionally enabled/disabled extension module lines. The file is not used, yet.

bpo-45573 [https://bugs.python.org/issue?@action=redirect&bpo=45573]: configure now uses a unified format to set state, compiler flags, and linker flags in Makefile. The new macro PY_STDLIB_MOD sets three variables that are consumed by Modules/Setup and setup.py.

bpo-45816 [https://bugs.python.org/issue?@action=redirect&bpo=45816]: Python now supports building with Visual Studio 2022 (MSVC v143, VS Version 17.0). Patch by Jeremiah Vivian.

bpo-45800 [https://bugs.python.org/issue?@action=redirect&bpo=45800]: Settings for pyexpat C extension are now detected by configure. The bundled expat library is built in Makefile.

bpo-45798 [https://bugs.python.org/issue?@action=redirect&bpo=45798]: Settings for decimal internal C extension are now detected by configure. The bundled libmpdec library is built in Makefile.

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: configure has a new option --with-pkg-config to disable or require pkg-config.

bpo-45774 [https://bugs.python.org/issue?@action=redirect&bpo=45774]: The build dependencies for sqlite3 are now detected by configure and pkg-config. Patch by Erlend E. Aasland.

bpo-45763 [https://bugs.python.org/issue?@action=redirect&bpo=45763]: The build dependencies for zlib, bz2, and lzma are now detected by configure.

bpo-45747 [https://bugs.python.org/issue?@action=redirect&bpo=45747]: gdbm and dbm build dependencies are now detected by configure.

bpo-45743 [https://bugs.python.org/issue?@action=redirect&bpo=45743]: On macOS, the build system no longer passes search_paths_first to the linker. The flag has been the default since Xcode 4 / macOS 10.6.

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: configure.ac is now compatible with autoconf 2.71. Deprecated checks STDC_HEADERS and AC_HEADER_TIME have been removed.

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: configure now prints a warning when pkg-config is missing.

bpo-45731 [https://bugs.python.org/issue?@action=redirect&bpo=45731]: configure --enable-loadable-sqlite-extensions is now handled by new PY_SQLITE_ENABLE_LOAD_EXTENSION macro instead of logic in setup.py.

bpo-45723 [https://bugs.python.org/issue?@action=redirect&bpo=45723]: configure.ac now uses custom helper macros and AC_CACHE_CHECK to simplify and speed up configure runs.

bpo-45696 [https://bugs.python.org/issue?@action=redirect&bpo=45696]: Skip the marshal step for frozen modules by generating C code that produces a set of ready-to-use code objects. This speeds up startup time by another 10% or more.

bpo-45561 [https://bugs.python.org/issue?@action=redirect&bpo=45561]: Run smelly.py tool from $(srcdir).

Windows

bpo-46105 [https://bugs.python.org/issue?@action=redirect&bpo=46105]: Fixed calculation of sys.path in a venv on Windows.

bpo-45901 [https://bugs.python.org/issue?@action=redirect&bpo=45901]: When installed through the Microsoft Store and set as the default app for *.py files, command line arguments will now be passed to Python when invoking a script without explicitly launching Python (that is, script.py args rather than python script.py args).

bpo-45616 [https://bugs.python.org/issue?@action=redirect&bpo=45616]: Fix Python Launcher’s ability to distinguish between versions 3.1 and 3.10 when either one is explicitly requested. Previously, 3.1 would be used if 3.10 was requested but not installed, and 3.10 would be used if 3.1 was requested but 3.10 was installed.

bpo-45850 [https://bugs.python.org/issue?@action=redirect&bpo=45850]: Implement changes to build with deep-frozen modules on Windows. Note that we now require Python 3.10 as the “bootstrap” or “host” Python.

bpo-45732 [https://bugs.python.org/issue?@action=redirect&bpo=45732]: Updates bundled Tcl/Tk to 8.6.12.

bpo-45720 [https://bugs.python.org/issue?@action=redirect&bpo=45720]: Internal reference to shlwapi.dll was dropped to help improve startup time. This DLL will no longer be loaded at the start of every Python process.

macOS

bpo-45732 [https://bugs.python.org/issue?@action=redirect&bpo=45732]: Update python.org macOS installer to use Tcl/Tk 8.6.12.

C API

bpo-39026 [https://bugs.python.org/issue?@action=redirect&bpo=39026]: Fix Python.h to build C extensions with Xcode: remove a relative include from Include/cpython/pystate.h.

Python 3.11.0 alpha 2

Release date: 2021-11-05

Core and Builtins

bpo-45716 [https://bugs.python.org/issue?@action=redirect&bpo=45716]: Improve the SyntaxError message when using True, None or False as keywords in a function call. Patch by Pablo Galindo.

bpo-45688 [https://bugs.python.org/issue?@action=redirect&bpo=45688]: sys.stdlib_module_names now contains the macOS-specific module _scproxy.

bpo-45379 [https://bugs.python.org/issue?@action=redirect&bpo=45379]: Clarify ImportError message when we try to explicitly import a frozen module but frozen modules are disabled.

bpo-44525 [https://bugs.python.org/issue?@action=redirect&bpo=44525]: Specialize simple calls to Python functions (no starargs, keyword dict, or closure)

bpo-45530 [https://bugs.python.org/issue?@action=redirect&bpo=45530]: Cases of sorting using tuples as keys may now be significantly faster in some cases. Patch by Tim Peters.

The order of the result may differ from earlier releases if the tuple elements don’t define a total ordering (see 값 비교 for information on total ordering). It’s generally true that the result of sorting simply isn’t well-defined in the absence of a total ordering on list elements.

bpo-45526 [https://bugs.python.org/issue?@action=redirect&bpo=45526]: In obmalloc, set ADDRESS_BITS to not ignore any bits (ignored 16 before). That is safer in the case that the kernel gives user-space virtual addresses that span a range greater than 48 bits.

bpo-30570 [https://bugs.python.org/issue?@action=redirect&bpo=30570]: Fixed a crash in issubclass() from infinite recursion when searching pathological __bases__ tuples.

bpo-45521 [https://bugs.python.org/issue?@action=redirect&bpo=45521]: Fix a bug in the obmalloc radix tree code. On 64-bit machines, the bug causes the tree to hold 46-bits of virtual addresses, rather than the intended 48-bits.

bpo-45494 [https://bugs.python.org/issue?@action=redirect&bpo=45494]: Fix parser crash when reporting errors involving invalid continuation characters. Patch by Pablo Galindo.

bpo-45445 [https://bugs.python.org/issue?@action=redirect&bpo=45445]: Python now fails to initialize if it finds an invalid -X option in the command line. Patch by Pablo Galindo.

bpo-45340 [https://bugs.python.org/issue?@action=redirect&bpo=45340]: Object attributes are held in an array instead of a dictionary. An object’s dictionary are created lazily, only when needed. Reduces the memory consumption of a typical Python object by about 30%. Patch by Mark Shannon.

bpo-45408 [https://bugs.python.org/issue?@action=redirect&bpo=45408]: Fix a crash in the parser when reporting tokenizer errors that occur at the same time unclosed parentheses are detected. Patch by Pablo Galindo.

bpo-29410 [https://bugs.python.org/issue?@action=redirect&bpo=29410]: Add SipHash13 for string hash algorithm and use it by default.

bpo-45385 [https://bugs.python.org/issue?@action=redirect&bpo=45385]: Fix reference leak from descr_check. Patch by Donghee Na.

bpo-45367 [https://bugs.python.org/issue?@action=redirect&bpo=45367]: Specialized the BINARY_MULTIPLY opcode to BINARY_MULTIPLY_INT and BINARY_MULTIPLY_FLOAT using the PEP 659 machinery.

bpo-21736 [https://bugs.python.org/issue?@action=redirect&bpo=21736]: Frozen stdlib modules now have __file__ to the .py file they would otherwise be loaded from, if possible. For packages, __path__ now has the correct entry instead of being an empty list, which allows unfrozen submodules to be imported. These are set only if the stdlib directory is known when the runtime is initialized. Note that the file at __file__ is not guaranteed to exist. None of this affects non-stdlib frozen modules nor, for now, frozen modules imported using PyImport_ImportFrozenModule(). Also, at the moment co_filename is not updated for the module.

bpo-45020 [https://bugs.python.org/issue?@action=redirect&bpo=45020]: For frozen stdlib modules, record the original module name as module.__spec__.loader_state.origname. If the value is different than module.__spec__.name then the module was defined as an alias in Tools/scripts/freeze_modules.py. If it is None then the module comes from a source file outside the stdlib.

bpo-45324 [https://bugs.python.org/issue?@action=redirect&bpo=45324]: In FrozenImporter.find_spec(), we now preserve the information needed in exec_module() to load the module. This change mostly impacts internal details, rather than changing the importer’s behavior.

bpo-45292 [https://bugs.python.org/issue?@action=redirect&bpo=45292]: Implement PEP 654 [https://peps.python.org/pep-0654/]. Add ExceptionGroup and BaseExceptionGroup. Update traceback display code.

bpo-40116 [https://bugs.python.org/issue?@action=redirect&bpo=40116]: Change to the implementation of split dictionaries. Classes where the instances differ either in the exact set of attributes, or in the order in which those attributes are set, can still share keys. This should have no observable effect on users of Python or the C-API. Patch by Mark Shannon.

bpo-44050 [https://bugs.python.org/issue?@action=redirect&bpo=44050]: Extensions that indicate they use global state (by setting m_size to -1) can again be used in multiple interpreters. This reverts to behavior of Python 3.8.

bpo-44525 [https://bugs.python.org/issue?@action=redirect&bpo=44525]: Setup initial specialization infrastructure for the CALL_FUNCTION opcode. Implemented initial specializations for C function calls:

CALL_FUNCTION_BUILTIN_O for METH_O flag.

CALL_FUNCTION_BUILTIN_FAST for METH_FASTCALL flag without keywords.

CALL_FUNCTION_LEN for len(o).

CALL_FUNCTION_ISINSTANCE for isinstance(o, t).

bpo-44511 [https://bugs.python.org/issue?@action=redirect&bpo=44511]: Improve the generated bytecode for class and mapping patterns.

bpo-43706 [https://bugs.python.org/issue?@action=redirect&bpo=43706]: Speed up calls to enumerate() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

Library

bpo-45679 [https://bugs.python.org/issue?@action=redirect&bpo=45679]: Fix caching of multi-value typing.Literal. Literal[True, 2] is no longer equal to Literal[1, 2].

bpo-42064 [https://bugs.python.org/issue?@action=redirect&bpo=42064]: Convert sqlite3 to multi-phase initialisation (PEP 489). Patches by Erlend E. Aasland.

bpo-45438 [https://bugs.python.org/issue?@action=redirect&bpo=45438]: Fix typing.Signature string representation for generic builtin types.

bpo-45613 [https://bugs.python.org/issue?@action=redirect&bpo=45613]: sqlite3 now sets sqlite3.threadsafety based on the default threading mode the underlying SQLite library has been compiled with. Patch by Erlend E. Aasland.

bpo-45574 [https://bugs.python.org/issue?@action=redirect&bpo=45574]: Fix warning about print_escape being unused.

bpo-45581 [https://bugs.python.org/issue?@action=redirect&bpo=45581]: sqlite3.connect() now correctly raises MemoryError if the underlying SQLite API signals memory error. Patch by Erlend E. Aasland.

bpo-45557 [https://bugs.python.org/issue?@action=redirect&bpo=45557]: pprint.pprint() now handles underscore_numbers correctly. Previously it was always setting it to False.

bpo-44019 [https://bugs.python.org/issue?@action=redirect&bpo=44019]: Add operator.call() to operator.__all__. Patch by Kreusada.

bpo-42174 [https://bugs.python.org/issue?@action=redirect&bpo=42174]: shutil.get_terminal_size() now falls back to sane values if the column or line count are 0.

bpo-35673 [https://bugs.python.org/issue?@action=redirect&bpo=35673]: Improve the introspectability of the __loader__ attribute for namespace packages. importlib.machinery.NamespaceLoader is now public, and implements the importlib.abc.InspectLoader interface. _NamespaceLoader is kept for backward compatibility.

bpo-45515 [https://bugs.python.org/issue?@action=redirect&bpo=45515]: Add references to zoneinfo in the datetime documentation, mostly replacing outdated references to dateutil.tz. Change by Paul Ganssle.

bpo-45475 [https://bugs.python.org/issue?@action=redirect&bpo=45475]: Reverted optimization of iterating gzip.GzipFile, bz2.BZ2File, and lzma.LZMAFile (see bpo-43787 [https://bugs.python.org/issue?@action=redirect&bpo=43787]) because it caused regression when user iterate them without having reference of them. Patch by Inada Naoki.

bpo-45489 [https://bugs.python.org/issue?@action=redirect&bpo=45489]: Update ForwardRef to support | operator. Patch by Donghee Na.

bpo-42222 [https://bugs.python.org/issue?@action=redirect&bpo=42222]: Removed deprecated support for float arguments in randrange().

bpo-45428 [https://bugs.python.org/issue?@action=redirect&bpo=45428]: Fix a regression in py_compile when reading filenames from standard input.

bpo-45467 [https://bugs.python.org/issue?@action=redirect&bpo=45467]: Fix incremental decoder and stream reader in the “raw-unicode-escape” codec. Previously they failed if the escape sequence was split.

bpo-45461 [https://bugs.python.org/issue?@action=redirect&bpo=45461]: Fix incremental decoder and stream reader in the “unicode-escape” codec. Previously they failed if the escape sequence was split.

bpo-45239 [https://bugs.python.org/issue?@action=redirect&bpo=45239]: Fixed email.utils.parsedate_tz() crashing with UnboundLocalError on certain invalid input instead of returning None. Patch by Ben Hoyt.

bpo-45417 [https://bugs.python.org/issue?@action=redirect&bpo=45417]: Fix quadratic behaviour in the enum module: Creation of enum classes with a lot of entries was quadratic.

bpo-45249 [https://bugs.python.org/issue?@action=redirect&bpo=45249]: Fix the behaviour of traceback.print_exc() when displaying the caret when the end_offset in the exception is set to 0. Patch by Pablo Galindo

bpo-45416 [https://bugs.python.org/issue?@action=redirect&bpo=45416]: Fix use of asyncio.Condition with explicit asyncio.Lock objects, which was a regression due to removal of explicit loop arguments. Patch by Joongi Kim.

bpo-20028 [https://bugs.python.org/issue?@action=redirect&bpo=20028]: Empty escapechar/quotechar is not allowed when initializing csv.Dialect. Patch by Vajrasky Kok and Donghee Na.

bpo-44904 [https://bugs.python.org/issue?@action=redirect&bpo=44904]: Fix bug in the doctest module that caused it to fail if a docstring included an example with a classmethod property. Patch by Alex Waygood.

bpo-45406 [https://bugs.python.org/issue?@action=redirect&bpo=45406]: Make inspect.getmodule() catch FileNotFoundError raised by inspect.getabsfile(), and return None to indicate that the module could not be determined.

bpo-45411 [https://bugs.python.org/issue?@action=redirect&bpo=45411]: Add extensions for files containing subtitles - .srt & .vtt - to the mimetypes.py module.

bpo-10716 [https://bugs.python.org/issue?@action=redirect&bpo=10716]: Migrated pydoc to HTML5 (without changing the look of it). Side effect is to update xmlrpc’s ServerHTMLDoc which now uses the CSS too. cgitb now relies less on pydoc (as it can’t use the CSS file).

bpo-27580 [https://bugs.python.org/issue?@action=redirect&bpo=27580]: Add support of null characters in csv.

bpo-45262 [https://bugs.python.org/issue?@action=redirect&bpo=45262]: Prevent use-after-free in asyncio. Make sure the cached running loop holder gets cleared on dealloc to prevent use-after-free in get_running_loop

bpo-45386 [https://bugs.python.org/issue?@action=redirect&bpo=45386]: Make xmlrpc.client more robust to C runtimes where the underlying C strftime function results in a ValueError when testing for year formatting options.

bpo-20028 [https://bugs.python.org/issue?@action=redirect&bpo=20028]: Improve error message of csv.Dialect when initializing. Patch by Vajrasky Kok and Donghee Na.

bpo-45343 [https://bugs.python.org/issue?@action=redirect&bpo=45343]: Update bundled pip to 21.2.4 and setuptools to 58.1.0

bpo-45328 [https://bugs.python.org/issue?@action=redirect&bpo=45328]: Fixed http.client.HTTPConnection to work properly in OSs that don’t support the TCP_NODELAY socket option.

bpo-45243 [https://bugs.python.org/issue?@action=redirect&bpo=45243]: Add setlimit() and getlimit() to sqlite3.Connection for setting and getting SQLite limits by connection basis. Patch by Erlend E. Aasland.

bpo-45320 [https://bugs.python.org/issue?@action=redirect&bpo=45320]: Removed from the inspect module:

the getargspec function, deprecated since Python 3.0;

use inspect.signature() or inspect.getfullargspec() instead.

the formatargspec function, deprecated since Python 3.5; use the inspect.signature() function and Signature object directly.

the undocumented Signature.from_builtin and Signature.from_function functions, deprecated since Python 3.5; use the Signature.from_callable() method instead.

Patch by Hugo van Kemenade.

bpo-45192 [https://bugs.python.org/issue?@action=redirect&bpo=45192]: Fix the tempfile._infer_return_type function so that the dir argument of the tempfile functions accepts an object implementing the os.PathLike protocol.

Patch by Kyungmin Lee.

bpo-45160 [https://bugs.python.org/issue?@action=redirect&bpo=45160]: When tracing a tkinter variable used by a ttk OptionMenu, callbacks are no longer made twice.

bpo-25625 [https://bugs.python.org/issue?@action=redirect&bpo=25625]: Added non parallel-safe chdir() context manager to change the current working directory and then restore it on exit. Simple wrapper around chdir().

bpo-24139 [https://bugs.python.org/issue?@action=redirect&bpo=24139]: Add support for SQLite extended result codes in sqlite3.Error. Patch by Erlend E. Aasland.

bpo-24444 [https://bugs.python.org/issue?@action=redirect&bpo=24444]: Fixed an error raised in argparse help display when help for an option is set to 1+ blank spaces or when choices arg is an empty container.

bpo-44547 [https://bugs.python.org/issue?@action=redirect&bpo=44547]: Implement Fraction.__int__, so that a fractions.Fraction instance f passes an isinstance(f, typing.SupportsInt) check.

bpo-40321 [https://bugs.python.org/issue?@action=redirect&bpo=40321]: Adds support for HTTP 308 redirects to urllib. See RFC 7538 [https://datatracker.ietf.org/doc/html/rfc7538.html] for details. Patch by Jochem Schulenklopper.

bpo-41374 [https://bugs.python.org/issue?@action=redirect&bpo=41374]: Ensure that socket.TCP_* constants are exposed on Cygwin 3.1.6 and greater.

bpo-35970 [https://bugs.python.org/issue?@action=redirect&bpo=35970]: Add help flag to the base64 module’s command line interface. Patch contributed by Robert Kuska.

Documentation

bpo-45726 [https://bugs.python.org/issue?@action=redirect&bpo=45726]: Improve documentation for functools.singledispatch() and functools.singledispatchmethod.

bpo-45680 [https://bugs.python.org/issue?@action=redirect&bpo=45680]: Amend the docs on GenericAlias objects to clarify that non-container classes can also implement __class_getitem__. Patch contributed by Alex Waygood.

bpo-45618 [https://bugs.python.org/issue?@action=redirect&bpo=45618]: Update Sphinx version used to build the documentation to 4.2.0. Patch by Maciej Olko.

bpo-45655 [https://bugs.python.org/issue?@action=redirect&bpo=45655]: Add a new “relevant PEPs” section to the top of the documentation for the typing module. Patch by Alex Waygood.

bpo-45604 [https://bugs.python.org/issue?@action=redirect&bpo=45604]: Add level argument to multiprocessing.log_to_stderr function docs.

bpo-45516 [https://bugs.python.org/issue?@action=redirect&bpo=45516]: Add protocol description to the importlib.abc.TraversableResources documentation.

bpo-45464 [https://bugs.python.org/issue?@action=redirect&bpo=45464]: Mention in the documentation of Built-in Exceptions that inheriting from multiple exception types in a single subclass is not recommended due to possible memory layout incompatibility.

bpo-45449 [https://bugs.python.org/issue?@action=redirect&bpo=45449]: Add note about PEP 585 [https://peps.python.org/pep-0585/] in collections.abc.

bpo-45516 [https://bugs.python.org/issue?@action=redirect&bpo=45516]: Add protocol description to the importlib.abc.Traversable documentation.

bpo-20692 [https://bugs.python.org/issue?@action=redirect&bpo=20692]: Add Programming FAQ entry explaining that int literal attribute access requires either a space after or parentheses around the literal.

Tests

bpo-45678 [https://bugs.python.org/issue?@action=redirect&bpo=45678]: Add tests for scenarios in which functools.singledispatchmethod is stacked on top of a method that has already been wrapped by two other decorators. Patch by Alex Waygood.

bpo-45578 [https://bugs.python.org/issue?@action=redirect&bpo=45578]: Add tests for dis.distb()

bpo-45678 [https://bugs.python.org/issue?@action=redirect&bpo=45678]: Add tests to ensure that functools.singledispatchmethod correctly wraps the attributes of the target function.

bpo-45668 [https://bugs.python.org/issue?@action=redirect&bpo=45668]: PGO tests now pass when Python is built without test extension modules.

bpo-45577 [https://bugs.python.org/issue?@action=redirect&bpo=45577]: Add subtests for all pickle protocols in test_zoneinfo.

bpo-45566 [https://bugs.python.org/issue?@action=redirect&bpo=45566]: Fix test_frozen_pickle in test_dataclasses to check all pickle versions.

bpo-43592 [https://bugs.python.org/issue?@action=redirect&bpo=43592]: test.libregrtest now raises the soft resource limit for the maximum number of file descriptors when the default is too low for our test suite as was often the case on macOS.

bpo-39679 [https://bugs.python.org/issue?@action=redirect&bpo=39679]: Add more test cases for @functools.singledispatchmethod when combined with @classmethod or @staticmethod.

bpo-45410 [https://bugs.python.org/issue?@action=redirect&bpo=45410]: When libregrtest spawns a worker process, stderr is now written into stdout to keep messages order. Use a single pipe for stdout and stderr, rather than two pipes. Previously, messages were out of order which made analysis of buildbot logs harder Patch by Victor Stinner.

bpo-45402 [https://bugs.python.org/issue?@action=redirect&bpo=45402]: Fix test_tools.test_sundry() when Python is built out of tree: fix how the freeze_modules.py tool locates the _freeze_module program. Patch by Victor Stinner.

bpo-45403 [https://bugs.python.org/issue?@action=redirect&bpo=45403]: Fix test_sys.test_stdlib_dir() when Python is built outside the source tree: compare normalized paths. Patch by Victor Stinner.

bpo-45400 [https://bugs.python.org/issue?@action=redirect&bpo=45400]: Fix test_name_error_suggestions_do_not_trigger_for_too_many_locals() of test_exceptions if a directory name contains “a1” (like “Python-3.11.0a1”): use a stricter regular expression. Patch by Victor Stinner.

bpo-10572 [https://bugs.python.org/issue?@action=redirect&bpo=10572]: Rename sqlite3 tests from test_sqlite to test_sqlite3, and relocate them to Lib/test/test_sqlite3. Patch by Erlend E. Aasland.

Build

bpo-43158 [https://bugs.python.org/issue?@action=redirect&bpo=43158]: setup.py now uses values from configure script to build the _uuid extension module. Configure now detects util-linux’s libuuid, too.

bpo-45666 [https://bugs.python.org/issue?@action=redirect&bpo=45666]: Fix warning of swprintf and %s usage in _testembed.c

bpo-45548 [https://bugs.python.org/issue?@action=redirect&bpo=45548]: Modules/Setup and Modules/makesetup have been improved. The Setup file now contains working rules for all extensions. Outdated comments have been removed. Rules defined by makesetup track dependencies correctly.

bpo-45548 [https://bugs.python.org/issue?@action=redirect&bpo=45548]: The math and cmath implementation now require a C99 compatible libm and no longer ship with workarounds for missing acosh, asinh, atanh, expm1, and log1p functions.

bpo-45595 [https://bugs.python.org/issue?@action=redirect&bpo=45595]: setup.py and makesetup now track build dependencies on all Python header files and module specific header files.

bpo-45571 [https://bugs.python.org/issue?@action=redirect&bpo=45571]: Modules/Setup now use PY_CFLAGS_NODIST instead of PY_CFLAGS to compile shared modules.

bpo-45570 [https://bugs.python.org/issue?@action=redirect&bpo=45570]: pyexpat and _elementtree no longer define obsolete macros HAVE_EXPAT_CONFIG_H and USE_PYEXPAT_CAPI. XML_POOR_ENTROPY is now defined in expat_config.h.

bpo-43974 [https://bugs.python.org/issue?@action=redirect&bpo=43974]: setup.py no longer defines Py_BUILD_CORE_MODULE. Instead every module, that uses the internal API, defines the macro.

bpo-45548 [https://bugs.python.org/issue?@action=redirect&bpo=45548]: Fill in missing entries in Modules/Setup.

bpo-45532 [https://bugs.python.org/issue?@action=redirect&bpo=45532]: Update sys.version to use main as fallback information. Patch by Jeong YunWon.

bpo-45536 [https://bugs.python.org/issue?@action=redirect&bpo=45536]: The configure script now checks whether OpenSSL headers and libraries provide required APIs. Most common APIs are verified. The check detects outdated or missing OpenSSL. Failures do not stop configure.

bpo-45221 [https://bugs.python.org/issue?@action=redirect&bpo=45221]: Fixed regression in handling of LDFLAGS and CPPFLAGS options where argparse.parse_known_args() could interpret an option as one of the built-in command line argument, for example -h for help.

bpo-45440 [https://bugs.python.org/issue?@action=redirect&bpo=45440]: Building Python now requires a C99 <math.h> header file providing the following functions: copysign(), hypot(), isfinite(), isinf(), isnan(), round(). Patch by Victor Stinner.

bpo-45405 [https://bugs.python.org/issue?@action=redirect&bpo=45405]: Prevent internal configure error when running configure with recent versions of non-Apple clang. Patch by David Bohman.

bpo-45433 [https://bugs.python.org/issue?@action=redirect&bpo=45433]: Avoid linking libpython with libcrypt.

Windows

bpo-43652 [https://bugs.python.org/issue?@action=redirect&bpo=43652]: Update Tcl/Tk to 8.6.11, actually this time. The previous update incorrectly included 8.6.10.

bpo-45337 [https://bugs.python.org/issue?@action=redirect&bpo=45337]: venv now warns when the created environment may need to be accessed at a different path, due to redirections, links or junctions. It also now correctly installs or upgrades components when the alternate path is required.

bpo-43851 [https://bugs.python.org/issue?@action=redirect&bpo=43851]: Build SQLite SQLITE_OMIT_AUTOINIT on Windows. Patch by Erlend E. Aasland.

macOS

bpo-44828 [https://bugs.python.org/issue?@action=redirect&bpo=44828]: Avoid tkinter file dialog failure on macOS 12 Monterey when using the Tk 8.6.11 provided by python.org macOS installers. Patch by Marc Culler of the Tk project.

IDLE

bpo-45495 [https://bugs.python.org/issue?@action=redirect&bpo=45495]: Add context keywords ‘case’ and ‘match’ to completions list.

C API

bpo-29103 [https://bugs.python.org/issue?@action=redirect&bpo=29103]: PyType_FromSpec* now copies the class name from the spec to a buffer owned by the class, so the original can be safely deallocated. Patch by Petr Viktorin.

bpo-45522 [https://bugs.python.org/issue?@action=redirect&bpo=45522]: The internal freelists for frame, float, list, dict, async generators, and context objects can now be disabled.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: Exclude PyWeakref_GET_OBJECT() from the limited C API. It never worked since the PyWeakReference structure is opaque in the limited C API.

bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Move the interpreteridobject.h header file from Include/ to Include/internal/. It only provides private functions. Patch by Victor Stinner.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: The non-limited API files cellobject.h, classobject.h, context.h, funcobject.h, genobject.h and longintrepr.h have been moved to the Include/cpython directory. Moreover, the eval.h header file was removed. These files must not be included directly, as they are already included in Python.h: Include Files. If they have been included directly, consider including Python.h instead. Patch by Victor Stinner.

bpo-45474 [https://bugs.python.org/issue?@action=redirect&bpo=45474]: The following items are no longer available when Py_LIMITED_API is defined:

PyMarshal_WriteLongToFile()

PyMarshal_WriteObjectToFile()

PyMarshal_ReadObjectFromString()

PyMarshal_WriteObjectToString()

the Py_MARSHAL_VERSION macro

These are not part of the limited API.

Patch by Victor Stinner.

bpo-45434 [https://bugs.python.org/issue?@action=redirect&bpo=45434]: Remove the pystrhex.h header file. It only contains private functions. C extensions should only include the main <Python.h> header file. Patch by Victor Stinner.

bpo-45440 [https://bugs.python.org/issue?@action=redirect&bpo=45440]: Remove the Py_FORCE_DOUBLE() macro. It was used by the Py_IS_INFINITY() macro. Patch by Victor Stinner.

bpo-45434 [https://bugs.python.org/issue?@action=redirect&bpo=45434]: <Python.h> no longer includes the header files <stdlib.h>, <stdio.h>, <errno.h> and <string.h> when the Py_LIMITED_API macro is set to 0x030b0000 (Python 3.11) or higher. C extensions should explicitly include the header files after #include <Python.h>. Patch by Victor Stinner.

bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123]: Remove Py_UNICODE_COPY() and Py_UNICODE_FILL() macros, deprecated since Python 3.3. Use PyUnicode_CopyCharacters() or memcpy() (wchar_t* string), and PyUnicode_Fill() functions instead. Patch by Victor Stinner.

bpo-45412 [https://bugs.python.org/issue?@action=redirect&bpo=45412]: Remove the following math macros using the errno variable:

Py_ADJUST_ERANGE1()

Py_ADJUST_ERANGE2()

Py_OVERFLOWED()

Py_SET_ERANGE_IF_OVERFLOW()

Py_SET_ERRNO_ON_MATH_ERROR()

Patch by Victor Stinner.

bpo-45395 [https://bugs.python.org/issue?@action=redirect&bpo=45395]: Custom frozen modules (the array set to PyImport_FrozenModules) are now treated as additions, rather than replacing all the default frozen modules. Frozen stdlib modules can still be disabled by setting the “code” field of the custom array entry to NULL.

bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760]: Add new PyThreadState_EnterTracing(), and PyThreadState_LeaveTracing() functions to the limited C API to suspend and resume tracing and profiling. Patch by Victor Stinner.

bpo-44220 [https://bugs.python.org/issue?@action=redirect&bpo=44220]: PyStructSequence_UnnamedField is added to the Stable ABI.

Python 3.11.0 alpha 1

Release date: 2021-10-05

Security

bpo-42278 [https://bugs.python.org/issue?@action=redirect&bpo=42278]: Replaced usage of tempfile.mktemp() with TemporaryDirectory to avoid a potential race condition.

bpo-44600 [https://bugs.python.org/issue?@action=redirect&bpo=44600]: Fix incorrect line numbers while tracing some failed patterns in match statements. Patch by Charles Burkland.

bpo-41180 [https://bugs.python.org/issue?@action=redirect&bpo=41180]: Add auditing events to the marshal module, and stop raising code.__init__ events for every unmarshalled code object. Directly instantiated code objects will continue to raise an event, and audit event handlers should inspect or collect the raw marshal data. This reduces a significant performance overhead when loading from .pyc files.

bpo-44394 [https://bugs.python.org/issue?@action=redirect&bpo=44394]: Update the vendored copy of libexpat to 2.4.1 (from 2.2.8) to get the fix for the CVE 2013-0340 [https://www.cve.org/CVERecord?id=CVE-2013-0340] “Billion Laughs” vulnerability. This copy is most used on Windows and macOS.

bpo-43124 [https://bugs.python.org/issue?@action=redirect&bpo=43124]: Made the internal putcmd function in smtplib sanitize input for presence of \r and \n characters to avoid (unlikely) command injection.

bpo-44022 [https://bugs.python.org/issue?@action=redirect&bpo=44022]: http.client now avoids infinitely reading potential HTTP headers after a 100 Continue status response from the server.

Core and Builtins

bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760]: The number of hardware branches per instruction dispatch is reduced from two to one by adding a special instruction for tracing. Patch by Mark Shannon.

bpo-45061 [https://bugs.python.org/issue?@action=redirect&bpo=45061]: Add a deallocator to the bool type to detect refcount bugs in C extensions which call Py_DECREF(Py_True) or Py_DECREF(Py_False) by mistake. Detect also refcount bugs when the empty tuple singleton or the Unicode empty string singleton is destroyed by mistake. Patch by Victor Stinner.

bpo-24076 [https://bugs.python.org/issue?@action=redirect&bpo=24076]: sum() was further optimised for summing up single digit integers.

bpo-45190 [https://bugs.python.org/issue?@action=redirect&bpo=45190]: Update Unicode databases to Unicode 14.0.0.

bpo-45167 [https://bugs.python.org/issue?@action=redirect&bpo=45167]: Fix deepcopying of types.GenericAlias objects.

bpo-45155 [https://bugs.python.org/issue?@action=redirect&bpo=45155]: int.to_bytes() and int.from_bytes() now take a default value of "big" for the byteorder argument. int.to_bytes() also takes a default value of 1 for the length argument.

bpo-44219 [https://bugs.python.org/issue?@action=redirect&bpo=44219]: Release the GIL while performing isatty system calls on arbitrary file descriptors. In particular, this affects os.isatty(), os.device_encoding() and io.TextIOWrapper. By extension, io.open() in text mode is also affected. This change solves a deadlock in os.isatty(). Patch by Vincent Michel in bpo-44219 [https://bugs.python.org/issue?@action=redirect&bpo=44219].

bpo-44959 [https://bugs.python.org/issue?@action=redirect&bpo=44959]: Added fallback to extension modules with ‘.sl’ suffix on HP-UX

bpo-45121 [https://bugs.python.org/issue?@action=redirect&bpo=45121]: Fix issue where Protocol.__init__ raises RecursionError when it’s called directly or via super(). Patch provided by Yurii Karabas.

bpo-44348 [https://bugs.python.org/issue?@action=redirect&bpo=44348]: The deallocator function of the BaseException type now uses the trashcan mechanism to prevent stack overflow. For example, when a RecursionError instance is raised, it can be linked to another RecursionError through the __context__ attribute or the __traceback__ attribute, and then a chain of exceptions is created. When the chain is destroyed, nested deallocator function calls can crash with a stack overflow if the chain is too long compared to the available stack memory. Patch by Victor Stinner.

bpo-45123 [https://bugs.python.org/issue?@action=redirect&bpo=45123]: Fix PyAiter_Check to only check for the __anext__ presence (not for __aiter__). Rename PyAiter_Check to PyAIter_Check, PyObject_GetAiter -> PyObject_GetAIter.

bpo-1514420 [https://bugs.python.org/issue?@action=redirect&bpo=1514420]: Interpreter no longer attempts to open files with names in angle brackets (like “<string>” or “<stdin>”) when formatting an exception.

bpo-41031 [https://bugs.python.org/issue?@action=redirect&bpo=41031]: Match C and Python code formatting of unprintable exceptions and exceptions in the __main__ module.

bpo-37330 [https://bugs.python.org/issue?@action=redirect&bpo=37330]: open(), io.open(), codecs.open() and fileinput.FileInput no longer accept 'U' (“universal newline”) in the file mode. This flag was deprecated since Python 3.3. Patch by Victor Stinner.

bpo-45083 [https://bugs.python.org/issue?@action=redirect&bpo=45083]: When the interpreter renders an exception, its name now has a complete qualname. Previously only the class name was concatenated to the module name, which sometimes resulted in an incorrect full name being displayed.

(This issue impacted only the C code exception rendering, the traceback module was using qualname already).

bpo-34561 [https://bugs.python.org/issue?@action=redirect&bpo=34561]: List sorting now uses the merge-ordering strategy from Munro and Wild’s powersort(). Unlike the former strategy, this is provably near-optimal in the entropy of the distribution of run lengths. Most uses of list.sort() probably won’t see a significant time difference, but may see significant improvements in cases where the former strategy was exceptionally poor. However, as these are all fast linear-time approximations to a problem that’s inherently at best quadratic-time to solve truly optimally, it’s also possible to contrive cases where the former strategy did better.

bpo-45056 [https://bugs.python.org/issue?@action=redirect&bpo=45056]: Compiler now removes trailing unused constants from co_consts.

bpo-45020 [https://bugs.python.org/issue?@action=redirect&bpo=45020]: Add a new command line option, “-X frozen_modules=[on|off]” to opt out of (or into) using optional frozen modules. This defaults to “on” (or “off” if it’s running out of the source tree).

bpo-45012 [https://bugs.python.org/issue?@action=redirect&bpo=45012]: In posix, release GIL during stat(), lstat(), and fstatat() syscalls made by os.DirEntry.stat(). Patch by Stanisław Skonieczny.

bpo-45018 [https://bugs.python.org/issue?@action=redirect&bpo=45018]: Fixed pickling of range iterators that iterated for over 2**32 times.

bpo-45000 [https://bugs.python.org/issue?@action=redirect&bpo=45000]: A SyntaxError is now raised when trying to delete __debug__. Patch by Donghee Na.

bpo-44963 [https://bugs.python.org/issue?@action=redirect&bpo=44963]: Implement send() and throw() methods for anext_awaitable objects. Patch by Pablo Galindo.

bpo-44962 [https://bugs.python.org/issue?@action=redirect&bpo=44962]: Fix a race in WeakKeyDictionary, WeakValueDictionary and WeakSet when two threads attempt to commit the last pending removal. This fixes asyncio.create_task and fixes a data loss in asyncio.run where shutdown_asyncgens is not run

bpo-24234 [https://bugs.python.org/issue?@action=redirect&bpo=24234]: Implement the __bytes__() special method on the bytes type, so a bytes object b passes an isinstance(b, typing.SupportsBytes) check.

bpo-24234 [https://bugs.python.org/issue?@action=redirect&bpo=24234]: Implement the __complex__() special method on the complex type, so a complex number z passes an isinstance(z, typing.SupportsComplex) check.

bpo-44954 [https://bugs.python.org/issue?@action=redirect&bpo=44954]: Fixed a corner case bug where the result of float.fromhex('0x.8p-1074') was rounded the wrong way.

bpo-44947 [https://bugs.python.org/issue?@action=redirect&bpo=44947]: Refine the syntax error for trailing commas in import statements. Patch by Pablo Galindo.

bpo-44945 [https://bugs.python.org/issue?@action=redirect&bpo=44945]: Specialize the BINARY_ADD instruction using the PEP 659 machinery. Adds five new instructions:

BINARY_ADD_ADAPTIVE

BINARY_ADD_FLOAT

BINARY_ADD_INT

BINARY_ADD_UNICODE

BINARY_ADD_UNICODE_INPLACE_FAST

bpo-44929 [https://bugs.python.org/issue?@action=redirect&bpo=44929]: Fix some edge cases of enum.Flag string representation in the REPL. Patch by Pablo Galindo.

bpo-44914 [https://bugs.python.org/issue?@action=redirect&bpo=44914]: Class version tags are no longer recycled.

This means that a version tag serves as a unique identifier for the state of a class. We rely on this for effective specialization of the LOAD_ATTR and other instructions.

bpo-44698 [https://bugs.python.org/issue?@action=redirect&bpo=44698]: Restore behaviour of complex exponentiation with integer-valued exponent of type float or complex.

bpo-44895 [https://bugs.python.org/issue?@action=redirect&bpo=44895]: A debug variable PYTHONDUMPREFSFILE is added for creating a dump file which is generated by --with-trace-refs. Patch by Donghee Na.

bpo-44900 [https://bugs.python.org/issue?@action=redirect&bpo=44900]: Add five superinstructions for PEP 659 quickening:

LOAD_FAST LOAD_FAST

STORE_FAST LOAD_FAST

LOAD_FAST LOAD_CONST

LOAD_CONST LOAD_FAST

STORE_FAST STORE_FAST

bpo-44889 [https://bugs.python.org/issue?@action=redirect&bpo=44889]: Initial implementation of adaptive specialization of LOAD_METHOD. The following specialized forms were added:

LOAD_METHOD_CACHED

LOAD_METHOD_MODULE

LOAD_METHOD_CLASS

bpo-44890 [https://bugs.python.org/issue?@action=redirect&bpo=44890]: Specialization stats are always collected in debug builds.

bpo-44885 [https://bugs.python.org/issue?@action=redirect&bpo=44885]: Correct the ast locations of f-strings with format specs and repeated expressions. Patch by Pablo Galindo

bpo-44878 [https://bugs.python.org/issue?@action=redirect&bpo=44878]: Remove the loop from the bytecode interpreter. All instructions end with a DISPATCH macro, so the loop is now redundant.

bpo-44878 [https://bugs.python.org/issue?@action=redirect&bpo=44878]: Remove switch statement for interpreter loop when using computed gotos. This makes sure that we only have one dispatch table in the interpreter.

bpo-44874 [https://bugs.python.org/issue?@action=redirect&bpo=44874]: Deprecate the old trashcan macros (Py_TRASHCAN_SAFE_BEGIN/Py_TRASHCAN_SAFE_END). They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END.

bpo-44872 [https://bugs.python.org/issue?@action=redirect&bpo=44872]: Use new trashcan macros (Py_TRASHCAN_BEGIN/END) in frameobject.c instead of the old ones (Py_TRASHCAN_SAFE_BEGIN/END).

bpo-33930 [https://bugs.python.org/issue?@action=redirect&bpo=33930]: Fix segmentation fault with deep recursion when cleaning method objects. Patch by Augusto Goulart and Pablo Galindo.

bpo-25782 [https://bugs.python.org/issue?@action=redirect&bpo=25782]: Fix bug where PyErr_SetObject hangs when the current exception has a cycle in its context chain.

bpo-44856 [https://bugs.python.org/issue?@action=redirect&bpo=44856]: Fix reference leaks in the error paths of update_bases() and __build_class__. Patch by Pablo Galindo.

bpo-44826 [https://bugs.python.org/issue?@action=redirect&bpo=44826]: Initial implementation of adaptive specialization of STORE_ATTR

Three specialized forms of STORE_ATTR are added:

STORE_ATTR_SLOT

STORE_ATTR_SPLIT_KEYS

STORE_ATTR_WITH_HINT

bpo-44838 [https://bugs.python.org/issue?@action=redirect&bpo=44838]: Fixed a bug that was causing the parser to raise an incorrect custom SyntaxError for invalid ‘if’ expressions. Patch by Pablo Galindo.

bpo-44821 [https://bugs.python.org/issue?@action=redirect&bpo=44821]: Create instance dictionaries (__dict__) eagerly, to improve regularity of object layout and assist specialization.

bpo-44792 [https://bugs.python.org/issue?@action=redirect&bpo=44792]: Improve syntax errors for if expressions. Patch by Miguel Brito

bpo-34013 [https://bugs.python.org/issue?@action=redirect&bpo=34013]: Generalize the invalid legacy statement custom error message (like the one generated when “print” is called without parentheses) to include more generic expressions. Patch by Pablo Galindo

bpo-44732 [https://bugs.python.org/issue?@action=redirect&bpo=44732]: Rename types.Union to types.UnionType.

bpo-44725 [https://bugs.python.org/issue?@action=redirect&bpo=44725]: Expose specialization stats in python via _opcode.get_specialization_stats().

bpo-44717 [https://bugs.python.org/issue?@action=redirect&bpo=44717]: Improve AttributeError on circular imports of submodules.

bpo-44698 [https://bugs.python.org/issue?@action=redirect&bpo=44698]: Fix undefined behaviour in complex object exponentiation.

bpo-44653 [https://bugs.python.org/issue?@action=redirect&bpo=44653]: Support typing types in parameter substitution in the union type.

bpo-44676 [https://bugs.python.org/issue?@action=redirect&bpo=44676]: Add ability to serialise types.Union objects. Patch provided by Yurii Karabas.

bpo-44633 [https://bugs.python.org/issue?@action=redirect&bpo=44633]: Parameter substitution of the union type with wrong types now raises TypeError instead of returning NotImplemented.

bpo-44661 [https://bugs.python.org/issue?@action=redirect&bpo=44661]: Update property_descr_set to use vectorcall if possible. Patch by Donghee Na.

bpo-44662 [https://bugs.python.org/issue?@action=redirect&bpo=44662]: Add __module__ to types.Union. This also fixes types.Union issues with typing.Annotated. Patch provided by Yurii Karabas.

bpo-44655 [https://bugs.python.org/issue?@action=redirect&bpo=44655]: Include the name of the type in unset __slots__ attribute errors. Patch by Pablo Galindo

bpo-44655 [https://bugs.python.org/issue?@action=redirect&bpo=44655]: Don’t include a missing attribute with the same name as the failing one when offering suggestions for missing attributes. Patch by Pablo Galindo

bpo-44646 [https://bugs.python.org/issue?@action=redirect&bpo=44646]: Fix the hash of the union type: it no longer depends on the order of arguments.

bpo-44636 [https://bugs.python.org/issue?@action=redirect&bpo=44636]: Collapse union of equal types. E.g. the result of int | int is now int. Fix comparison of the union type with non-hashable objects. E.g. int | str == {} no longer raises a TypeError.

bpo-44611 [https://bugs.python.org/issue?@action=redirect&bpo=44611]: On Windows, os.urandom(): uses BCryptGenRandom API instead of CryptGenRandom API which is deprecated from Microsoft Windows API. Patch by Donghee Na.

bpo-44635 [https://bugs.python.org/issue?@action=redirect&bpo=44635]: Convert None to type(None) in the union type constructor.

bpo-26280 [https://bugs.python.org/issue?@action=redirect&bpo=26280]: Implement adaptive specialization for BINARY_SUBSCR

Three specialized forms of BINARY_SUBSCR are added:

BINARY_SUBSCR_LIST_INT

BINARY_SUBSCR_TUPLE_INT

BINARY_SUBSCR_DICT

bpo-44589 [https://bugs.python.org/issue?@action=redirect&bpo=44589]: Mapping patterns in match statements with two or more equal literal keys will now raise a SyntaxError at compile-time.

bpo-44606 [https://bugs.python.org/issue?@action=redirect&bpo=44606]: Fix __instancecheck__ and __subclasscheck__ for the union type.

bpo-42073 [https://bugs.python.org/issue?@action=redirect&bpo=42073]: The @classmethod decorator can now wrap other classmethod-like descriptors.

bpo-41972 [https://bugs.python.org/issue?@action=redirect&bpo=41972]: Tuned the string-searching algorithm of fastsearch.h to have a shorter inner loop for most cases.

bpo-44590 [https://bugs.python.org/issue?@action=redirect&bpo=44590]: All necessary data for executing a Python function (local variables, stack, etc) is now kept in a per-thread stack. Frame objects are lazily allocated on demand. This increases performance by about 7% on the standard benchmark suite. Introspection and debugging are unaffected as frame objects are always available when needed. Patch by Mark Shannon.

bpo-44584 [https://bugs.python.org/issue?@action=redirect&bpo=44584]: The threading debug (PYTHONTHREADDEBUG environment variable) is deprecated in Python 3.10 and will be removed in Python 3.12. This feature requires a debug build of Python. Patch by Victor Stinner.

bpo-43895 [https://bugs.python.org/issue?@action=redirect&bpo=43895]: An obsolete internal cache of shared object file handles added in 1995 that attempted, but did not guarantee, that a .so would not be dlopen’ed twice to work around flaws in mid-1990s posix-ish operating systems has been removed from dynload_shlib.c.

bpo-44490 [https://bugs.python.org/issue?@action=redirect&bpo=44490]: typing now searches for type parameters in types.Union objects. get_type_hints will also properly resolve annotations with nested types.Union objects. Patch provided by Yurii Karabas.

bpo-43950 [https://bugs.python.org/issue?@action=redirect&bpo=43950]: Code objects can now provide the column information for instructions when available. This is levaraged during traceback printing to show the expressions responsible for errors.

Contributed by Pablo Galindo, Batuhan Taskaya and Ammar Askar as part of PEP 657 [https://peps.python.org/pep-0657/].

bpo-44562 [https://bugs.python.org/issue?@action=redirect&bpo=44562]: Remove uses of PyObject_GC_Del() in error path when initializing types.GenericAlias.

bpo-41486 [https://bugs.python.org/issue?@action=redirect&bpo=41486]: Fix a memory consumption and copying performance regression in earlier 3.10 beta releases if someone used an output buffer larger than 4GiB with zlib.decompress on input data that expands that large.

bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908]: Heap types with the Py_TPFLAGS_IMMUTABLETYPE flag can now inherit the PEP 590 [https://peps.python.org/pep-0590/] vectorcall protocol. Previously, this was only possible for static types. Patch by Erlend E. Aasland.

bpo-44553 [https://bugs.python.org/issue?@action=redirect&bpo=44553]: Implement GC methods for types.Union to break reference cycles and prevent memory leaks.

bpo-44490 [https://bugs.python.org/issue?@action=redirect&bpo=44490]: Add __parameters__ attribute and __getitem__ operator to types.Union. Patch provided by Yurii Karabas.

bpo-44523 [https://bugs.python.org/issue?@action=redirect&bpo=44523]: Remove the pass-through for hash() of weakref.proxy objects to prevent unintended consequences when the original referred object dies while the proxy is part of a hashable object. Patch by Pablo Galindo.

bpo-44483 [https://bugs.python.org/issue?@action=redirect&bpo=44483]: Fix a crash in types.Union objects when creating a union of an object with bad __module__ field.

bpo-44486 [https://bugs.python.org/issue?@action=redirect&bpo=44486]: Modules will always have a dictionary, even when created by types.ModuleType.__new__()

bpo-44472 [https://bugs.python.org/issue?@action=redirect&bpo=44472]: Fix ltrace functionality when exceptions are raised. Patch by Pablo Galindo

bpo-12022 [https://bugs.python.org/issue?@action=redirect&bpo=12022]: A TypeError is now raised instead of an AttributeError in with and async with statements for objects which do not support the context manager or asynchronous context manager protocols correspondingly.

bpo-44297 [https://bugs.python.org/issue?@action=redirect&bpo=44297]: Make sure that the line number is set when entering a comprehension scope. This ensures that backtraces including generator expressions show the correct line number.

bpo-44456 [https://bugs.python.org/issue?@action=redirect&bpo=44456]: Improve the syntax error when mixing positional and keyword patterns. Patch by Pablo Galindo.

bpo-44409 [https://bugs.python.org/issue?@action=redirect&bpo=44409]: Fix error location information for tokenizer errors raised on initialization of the tokenizer. Patch by Pablo Galindo.

bpo-44396 [https://bugs.python.org/issue?@action=redirect&bpo=44396]: Fix a possible crash in the tokenizer when raising syntax errors for unclosed strings. Patch by Pablo Galindo.

bpo-44376 [https://bugs.python.org/issue?@action=redirect&bpo=44376]: Exact integer exponentiation (like i**2 or pow(i, 2)) with a small exponent is much faster, due to reducing overhead in such cases.

bpo-44313 [https://bugs.python.org/issue?@action=redirect&bpo=44313]: Directly imported objects and modules (through import and from import statements) don’t generate LOAD_METHOD/CALL_METHOD for directly accessed objects on their namespace. They now use the regular LOAD_ATTR/CALL_FUNCTION.

bpo-44338 [https://bugs.python.org/issue?@action=redirect&bpo=44338]: Implement adaptive specialization for LOAD_GLOBAL

Two specialized forms of LOAD_GLOBAL are added:

LOAD_GLOBAL_MODULE

LOAD_GLOBAL_BUILTIN

bpo-44368 [https://bugs.python.org/issue?@action=redirect&bpo=44368]: Improve syntax errors for invalid “as” targets. Patch by Pablo Galindo

bpo-44349 [https://bugs.python.org/issue?@action=redirect&bpo=44349]: Fix an edge case when displaying text from files with encoding in syntax errors. Patch by Pablo Galindo.

bpo-44337 [https://bugs.python.org/issue?@action=redirect&bpo=44337]: Initial implementation of adaptive specialization of LOAD_ATTR

Four specialized forms of LOAD_ATTR are added:

LOAD_ATTR_SLOT

LOAD_ATTR_SPLIT_KEYS

LOAD_ATTR_WITH_HINT

LOAD_ATTR_MODULE

bpo-44335 [https://bugs.python.org/issue?@action=redirect&bpo=44335]: Fix a regression when identifying incorrect characters in syntax errors. Patch by Pablo Galindo

bpo-43693 [https://bugs.python.org/issue?@action=redirect&bpo=43693]: Computation of the offsets of cell variables is done in the compiler instead of at runtime. This reduces the overhead of handling cell and free variables, especially in the case where a variable is both an argument and cell variable.

bpo-44317 [https://bugs.python.org/issue?@action=redirect&bpo=44317]: Improve tokenizer error with improved locations. Patch by Pablo Galindo.

bpo-44304 [https://bugs.python.org/issue?@action=redirect&bpo=44304]: Fix a crash in the sqlite3 module that happened when the garbage collector clears sqlite.Statement objects. Patch by Pablo Galindo

bpo-44305 [https://bugs.python.org/issue?@action=redirect&bpo=44305]: Improve error message for try blocks without except or finally blocks. Patch by Pablo Galindo.

bpo-43413 [https://bugs.python.org/issue?@action=redirect&bpo=43413]: Constructors of subclasses of some builtin classes (e.g. tuple, list, frozenset) no longer accept arbitrary keyword arguments. [reverted in 3.11a4] Subclass of set can now define a __new__() method with additional keyword parameters without overriding also __init__().

bpo-43667 [https://bugs.python.org/issue?@action=redirect&bpo=43667]: Improve Unicode support in non-UTF locales on Oracle Solaris. This issue does not affect other Solaris systems.

bpo-43693 [https://bugs.python.org/issue?@action=redirect&bpo=43693]: A new opcode MAKE_CELL has been added that effectively moves some of the work done on function entry into the compiler and into the eval loop. In addition to creating the required cell objects, the new opcode converts relevant arguments (and other locals) to cell variables on function entry.

bpo-44232 [https://bugs.python.org/issue?@action=redirect&bpo=44232]: Fix a regression in type() when a metaclass raises an exception. The C function type_new() must properly report the exception when a metaclass constructor raises an exception and the winner class is not the metaclass. Patch by Victor Stinner.

bpo-44201 [https://bugs.python.org/issue?@action=redirect&bpo=44201]: Avoid side effects of checking for specialized syntax errors in the REPL that was causing it to ask for extra tokens after a syntax error had been detected. Patch by Pablo Galindo

bpo-43693 [https://bugs.python.org/issue?@action=redirect&bpo=43693]: PyCodeObject gained co_fastlocalnames and co_fastlocalkinds as the authoritative source of fast locals info. Marshaled code objects have changed accordingly.

bpo-44184 [https://bugs.python.org/issue?@action=redirect&bpo=44184]: Fix a crash at Python exit when a deallocator function removes the last strong reference to a heap type. Patch by Victor Stinner.

bpo-44187 [https://bugs.python.org/issue?@action=redirect&bpo=44187]: Implement quickening in the interpreter. This offers no advantages as yet, but is an enabler of future optimizations. See PEP 659 for full explanation.

bpo-44180 [https://bugs.python.org/issue?@action=redirect&bpo=44180]: The parser doesn’t report generic syntax errors that happen in a position further away that the one it reached in the first pass. Patch by Pablo Galindo

bpo-44168 [https://bugs.python.org/issue?@action=redirect&bpo=44168]: Fix error message in the parser involving keyword arguments with invalid expressions. Patch by Pablo Galindo

bpo-44156 [https://bugs.python.org/issue?@action=redirect&bpo=44156]: String caches in compile.c are now subinterpreter compatible.

bpo-44143 [https://bugs.python.org/issue?@action=redirect&bpo=44143]: Fixed a crash in the parser that manifest when raising tokenizer errors when an existing exception was present. Patch by Pablo Galindo.

bpo-44032 [https://bugs.python.org/issue?@action=redirect&bpo=44032]: Move ‘fast’ locals and other variables from the frame object to a per-thread datastack.

bpo-44114 [https://bugs.python.org/issue?@action=redirect&bpo=44114]: Fix incorrect dictkeys_reversed and dictitems_reversed function signatures in C code, which broke webassembly builds.

bpo-44110 [https://bugs.python.org/issue?@action=redirect&bpo=44110]: Improve str.__getitem__() error message

bpo-26110 [https://bugs.python.org/issue?@action=redirect&bpo=26110]: Add CALL_METHOD_KW opcode to speed up method calls with keyword arguments. Idea originated from PyPy. A side effect is executing CALL_METHOD is now branchless in the evaluation loop.

bpo-28307 [https://bugs.python.org/issue?@action=redirect&bpo=28307]: Compiler now optimizes simple C-style formatting with literal format containing only format codes %s, %r and %a by converting them to f-string expressions.

bpo-43149 [https://bugs.python.org/issue?@action=redirect&bpo=43149]: Correct the syntax error message regarding multiple exception types to not refer to “exception groups”. Patch by Pablo Galindo

bpo-43822 [https://bugs.python.org/issue?@action=redirect&bpo=43822]: The parser will prioritize tokenizer errors over custom syntax errors when raising exceptions. Patch by Pablo Galindo.

bpo-40222 [https://bugs.python.org/issue?@action=redirect&bpo=40222]: “Zero cost” exception handling.

Uses a lookup table to determine how to handle exceptions.

Removes SETUP_FINALLY and POP_TOP block instructions, eliminating the runtime overhead of try statements.

Reduces the size of the frame object by about 60%.

Patch by Mark Shannon

bpo-43918 [https://bugs.python.org/issue?@action=redirect&bpo=43918]: Document the signature and default argument in the docstring of the new anext builtin.

bpo-43833 [https://bugs.python.org/issue?@action=redirect&bpo=43833]: Emit a deprecation warning if the numeric literal is immediately followed by one of keywords: and, else, for, if, in, is, or. Raise a syntax error with more informative message if it is immediately followed by other keyword or identifier.

bpo-43879 [https://bugs.python.org/issue?@action=redirect&bpo=43879]: Add native_thread_id to PyThreadState. Patch by Gabriele N. Tornetta.

bpo-43693 [https://bugs.python.org/issue?@action=redirect&bpo=43693]: Compute cell offsets relative to locals in compiler. Allows the interpreter to treats locals and cells a single array, which is slightly more efficient. Also make the LOAD_CLOSURE opcode an alias for LOAD_FAST. Preserving LOAD_CLOSURE helps keep bytecode a bit more readable.

bpo-17792 [https://bugs.python.org/issue?@action=redirect&bpo=17792]: More accurate error messages for access of unbound locals or free vars.

bpo-28146 [https://bugs.python.org/issue?@action=redirect&bpo=28146]: Fix a confusing error message in str.format().

bpo-11105 [https://bugs.python.org/issue?@action=redirect&bpo=11105]: When compiling ast.AST objects with recursive references through compile(), the interpreter doesn’t crash anymore instead it raises a RecursionError.

bpo-39091 [https://bugs.python.org/issue?@action=redirect&bpo=39091]: Fix crash when using passing a non-exception to a generator’s throw() method. Patch by Noah Oxer

bpo-33346 [https://bugs.python.org/issue?@action=redirect&bpo=33346]: Asynchronous comprehensions are now allowed inside comprehensions in asynchronous functions. Outer comprehensions implicitly become asynchronous.

Library

bpo-45371 [https://bugs.python.org/issue?@action=redirect&bpo=45371]: Fix clang rpath issue in distutils. The UnixCCompiler now uses correct clang option to add a runtime library directory (rpath) to a shared library.

bpo-45329 [https://bugs.python.org/issue?@action=redirect&bpo=45329]: Fix freed memory access in pyexpat.xmlparser when building it with an installed expat library <= 2.2.0.

bpo-41710 [https://bugs.python.org/issue?@action=redirect&bpo=41710]: On Unix, if the sem_clockwait() function is available in the C library (glibc 2.30 and newer), the threading.Lock.acquire() method now uses the monotonic clock (time.CLOCK_MONOTONIC) for the timeout, rather than using the system clock (time.CLOCK_REALTIME), to not be affected by system clock changes. Patch by Victor Stinner.

bpo-1596321 [https://bugs.python.org/issue?@action=redirect&bpo=1596321]: Fix the threading._shutdown() function when the threading module was imported first from a thread different than the main thread: no longer log an error at Python exit.

bpo-45274 [https://bugs.python.org/issue?@action=redirect&bpo=45274]: Fix a race condition in the Thread.join() method of the threading module. If the function is interrupted by a signal and the signal handler raises an exception, make sure that the thread remains in a consistent state to prevent a deadlock. Patch by Victor Stinner.

bpo-21302 [https://bugs.python.org/issue?@action=redirect&bpo=21302]: In Unix operating systems, time.sleep() now uses the nanosleep() function, if clock_nanosleep() is not available but nanosleep() is available. nanosleep() allows to sleep with nanosecond precision.

bpo-21302 [https://bugs.python.org/issue?@action=redirect&bpo=21302]: On Windows, time.sleep() now uses a waitable timer which has a resolution of 100 nanoseconds (10⁻⁷ seconds). Previously, it had a resolution of 1 millisecond (10⁻³ seconds). Patch by Benjamin Szőke and Victor Stinner.

bpo-45238 [https://bugs.python.org/issue?@action=redirect&bpo=45238]: Fix unittest.IsolatedAsyncioTestCase.debug(): it runs now asynchronous methods and callbacks.

bpo-36674 [https://bugs.python.org/issue?@action=redirect&bpo=36674]: unittest.TestCase.debug() raises now a unittest.SkipTest if the class or the test method are decorated with the skipping decorator.

bpo-45235 [https://bugs.python.org/issue?@action=redirect&bpo=45235]: Fix an issue where argparse would not preserve values in a provided namespace when using a subparser with defaults.

bpo-45183 [https://bugs.python.org/issue?@action=redirect&bpo=45183]: Have zipimport.zipimporter.find_spec() not raise an exception when the underlying zip file has been deleted and the internal cache has been reset via invalidate_cache().

bpo-45234 [https://bugs.python.org/issue?@action=redirect&bpo=45234]: Fixed a regression in copyfile(), copy(), copy2() raising FileNotFoundError when source is a directory, which should raise IsADirectoryError

bpo-45228 [https://bugs.python.org/issue?@action=redirect&bpo=45228]: Fix stack buffer overflow in parsing J1939 network address.

bpo-45225 [https://bugs.python.org/issue?@action=redirect&bpo=45225]: use map function instead of genexpr in capwords.

bpo-42135 [https://bugs.python.org/issue?@action=redirect&bpo=42135]: Fix typo: importlib.find_loader is really slated for removal in Python 3.12 not 3.10, like the others in PR 25169.

Patch by Hugo van Kemenade.

bpo-20524 [https://bugs.python.org/issue?@action=redirect&bpo=20524]: Improves error messages on .format() operation for str, float, int, and complex. New format now shows the problematic pattern and the object type.

bpo-45168 [https://bugs.python.org/issue?@action=redirect&bpo=45168]: Change dis.dis() output to omit op arg values that cannot be resolved due to co_consts, co_names etc not being provided. Previously the oparg itself was repeated in the value field, which is not useful and can be confusing.

bpo-21302 [https://bugs.python.org/issue?@action=redirect&bpo=21302]: In Unix operating systems, time.sleep() now uses the clock_nanosleep() function, if available, which allows to sleep for an interval specified with nanosecond precision.

bpo-45173 [https://bugs.python.org/issue?@action=redirect&bpo=45173]: Remove from the configparser module: the SafeConfigParser class, the filename property of the ParsingError class, the readfp() method of the ConfigParser class, deprecated since Python 3.2.

Patch by Hugo van Kemenade.

bpo-44987 [https://bugs.python.org/issue?@action=redirect&bpo=44987]: Pure ASCII strings are now normalized in constant time by unicodedata.normalize(). Patch by Donghee Na.

bpo-35474 [https://bugs.python.org/issue?@action=redirect&bpo=35474]: Calling mimetypes.guess_all_extensions() with strict=False no longer affects the result of the following call with strict=True. Also, mutating the returned list no longer affects the global state.

bpo-45166 [https://bugs.python.org/issue?@action=redirect&bpo=45166]: typing.get_type_hints() now works with Final wrapped in ForwardRef.

bpo-45162 [https://bugs.python.org/issue?@action=redirect&bpo=45162]: Remove many old deprecated unittest features:

“fail*” and “assert*” aliases of TestCase methods.

Broken from start TestCase method assertDictContainsSubset().

Ignored <unittest.TestLoader.loadTestsFromModule> TestLoader.loadTestsFromModule() parameter use_load_tests.

Old alias _TextTestResult of TextTestResult.

bpo-38371 [https://bugs.python.org/issue?@action=redirect&bpo=38371]: Remove the deprecated split() method of _tkinter.TkappType. Patch by Erlend E. Aasland.

bpo-20499 [https://bugs.python.org/issue?@action=redirect&bpo=20499]: Improve the speed and accuracy of statistics.pvariance().

bpo-45132 [https://bugs.python.org/issue?@action=redirect&bpo=45132]: Remove __getitem__() methods of xml.dom.pulldom.DOMEventStream, wsgiref.util.FileWrapper and fileinput.FileInput, deprecated since Python 3.9.

Patch by Hugo van Kemenade.

bpo-45129 [https://bugs.python.org/issue?@action=redirect&bpo=45129]: Due to significant security concerns, the reuse_address parameter of asyncio.loop.create_datagram_endpoint(), disabled in Python 3.9, is now entirely removed. This is because of the behavior of the socket option SO_REUSEADDR in UDP.

Patch by Hugo van Kemenade.

bpo-45124 [https://bugs.python.org/issue?@action=redirect&bpo=45124]: The bdist_msi command, deprecated in Python 3.9, is now removed.

Use bdist_wheel (wheel packages) instead.

Patch by Hugo van Kemenade.

bpo-30856 [https://bugs.python.org/issue?@action=redirect&bpo=30856]: unittest.TestResult methods addFailure(), addError(), addSkip() and addSubTest() are now called immediately after raising an exception in test or finishing a subtest. Previously they were called only after finishing the test clean up.

bpo-45034 [https://bugs.python.org/issue?@action=redirect&bpo=45034]: Changes how error is formatted for struct.pack with 'H' and 'h' modes and too large / small numbers. Now it shows the actual numeric limits, while previously it was showing arithmetic expressions.

bpo-25894 [https://bugs.python.org/issue?@action=redirect&bpo=25894]: unittest now always reports skipped and failed subtests separately: separate characters in default mode and separate lines in verbose mode. Also the test description is now output for errors in test method, class and module cleanups.

bpo-45081 [https://bugs.python.org/issue?@action=redirect&bpo=45081]: Fix issue when dataclasses that inherit from typing.Protocol subclasses have wrong __init__. Patch provided by Yurii Karabas.

bpo-45085 [https://bugs.python.org/issue?@action=redirect&bpo=45085]: The binhex module, deprecated in Python 3.9, is now removed. The following binascii functions, deprecated in Python 3.9, are now also removed:

a2b_hqx(), b2a_hqx();

rlecode_hqx(), rledecode_hqx().

The binascii.crc_hqx() function remains available.

Patch by Victor Stinner.

bpo-40360 [https://bugs.python.org/issue?@action=redirect&bpo=40360]: The lib2to3 package is now deprecated and may not be able to parse Python 3.10 or newer. See the PEP 617 [https://peps.python.org/pep-0617/] (New PEG parser for CPython). Patch by Victor Stinner.

bpo-45075 [https://bugs.python.org/issue?@action=redirect&bpo=45075]: Rename traceback.StackSummary.format_frame() to traceback.StackSummary.format_frame_summary(). This method was added for 3.11 so it was not released yet.

Updated code and docs to better distinguish frame and FrameSummary.

bpo-31299 [https://bugs.python.org/issue?@action=redirect&bpo=31299]: Add option to completely drop frames from a traceback by returning None from a format_frame() override.

bpo-41620 [https://bugs.python.org/issue?@action=redirect&bpo=41620]: run() now always return a TestResult instance. Previously it returned None if the test class or method was decorated with a skipping decorator.

bpo-45021 [https://bugs.python.org/issue?@action=redirect&bpo=45021]: Fix a potential deadlock at shutdown of forked children when using concurrent.futures module

bpo-43913 [https://bugs.python.org/issue?@action=redirect&bpo=43913]: Fix bugs in cleaning up classes and modules in unittest:

Functions registered with addModuleCleanup() were not called unless the user defines tearDownModule() in their test module.

Functions registered with addClassCleanup() were not called if tearDownClass is set to None.

Buffering in TestResult did not work with functions registered with addClassCleanup() and addModuleCleanup().

Errors in functions registered with addClassCleanup() and addModuleCleanup() were not handled correctly in buffered and debug modes.

Errors in setUpModule() and functions registered with addModuleCleanup() were reported in wrong order.

And several lesser bugs.

bpo-45030 [https://bugs.python.org/issue?@action=redirect&bpo=45030]: Fix integer overflow in pickling and copying the range iterator.

bpo-45001 [https://bugs.python.org/issue?@action=redirect&bpo=45001]: Made email date parsing more robust against malformed input, namely a whitespace-only Date: header. Patch by Wouter Bolsterlee.

bpo-45010 [https://bugs.python.org/issue?@action=redirect&bpo=45010]: Remove support of special method __div__ in unittest.mock. It is not used in Python 3.

bpo-39218 [https://bugs.python.org/issue?@action=redirect&bpo=39218]: Improve accuracy of variance calculations by using x*x instead of x**2.

bpo-43613 [https://bugs.python.org/issue?@action=redirect&bpo=43613]: Improve the speed of gzip.compress() and gzip.decompress() by compressing and decompressing at once in memory instead of in a streamed fashion.

bpo-37596 [https://bugs.python.org/issue?@action=redirect&bpo=37596]: Ensure that set and frozenset objects are always marshalled reproducibly.

bpo-44019 [https://bugs.python.org/issue?@action=redirect&bpo=44019]: A new function operator.call has been added, such that operator.call(obj, *args, **kwargs) == obj(*args, **kwargs).

bpo-42255 [https://bugs.python.org/issue?@action=redirect&bpo=42255]: webbrowser.MacOSX is deprecated and will be removed in Python 3.13. It is untested and undocumented and also not used by webbrowser itself. Patch by Donghee Na.

bpo-44955 [https://bugs.python.org/issue?@action=redirect&bpo=44955]: Method stopTestRun() is now always called in pair with method startTestRun() for TestResult objects implicitly created in run(). Previously it was not called for test methods and classes decorated with a skipping decorator.

bpo-39039 [https://bugs.python.org/issue?@action=redirect&bpo=39039]: tarfile.open raises ReadError when a zlib error occurs during file extraction.

bpo-44935 [https://bugs.python.org/issue?@action=redirect&bpo=44935]: subprocess on Solaris now also uses os.posix_spawn() for better performance.

bpo-44911 [https://bugs.python.org/issue?@action=redirect&bpo=44911]: IsolatedAsyncioTestCase will no longer throw an exception while cancelling leaked tasks. Patch by Bar Harel.

bpo-41322 [https://bugs.python.org/issue?@action=redirect&bpo=41322]: Added DeprecationWarning for tests and async tests that return a value!=None (as this may indicate an improperly written test, for example a test written as a generator function).

bpo-44524 [https://bugs.python.org/issue?@action=redirect&bpo=44524]: Make exception message more useful when subclass from typing special form alias. Patch provided by Yurii Karabas.

bpo-38956 [https://bugs.python.org/issue?@action=redirect&bpo=38956]: argparse.BooleanOptionalAction’s default value is no longer printed twice when used with argparse.ArgumentDefaultsHelpFormatter.

bpo-44860 [https://bugs.python.org/issue?@action=redirect&bpo=44860]: Fix the posix_user scheme in sysconfig to not depend on sys.platlibdir.

bpo-44859 [https://bugs.python.org/issue?@action=redirect&bpo=44859]: Improve error handling in sqlite3 and raise more accurate exceptions.

MemoryError is now raised instead of sqlite3.Warning when memory is not enough for encoding a statement to UTF-8 in Connection.__call__() and Cursor.execute().

UnicodEncodeError is now raised instead of sqlite3.Warning when the statement contains surrogate characters in Connection.__call__() and Cursor.execute().

TypeError is now raised instead of ValueError for non-string script argument in Cursor.executescript().

ValueError is now raised for script containing the null character instead of truncating it in Cursor.executescript().

Correctly handle exceptions raised when getting boolean value of the result of the progress handler.

Add many tests covering different corner cases.

bpo-44581 [https://bugs.python.org/issue?@action=redirect&bpo=44581]: Upgrade bundled pip to 21.2.3 and setuptools to 57.4.0

bpo-44849 [https://bugs.python.org/issue?@action=redirect&bpo=44849]: Fix the os.set_inheritable() function on FreeBSD 14 for file descriptor opened with the O_PATH flag: ignore the EBADF error on ioctl(), fallback on the fcntl() implementation. Patch by Victor Stinner.

bpo-44605 [https://bugs.python.org/issue?@action=redirect&bpo=44605]: The @functools.total_ordering() decorator now works with metaclasses.

bpo-44524 [https://bugs.python.org/issue?@action=redirect&bpo=44524]: Fixed an issue wherein the __name__ and __qualname__ attributes of subscribed specialforms could be None.

bpo-44839 [https://bugs.python.org/issue?@action=redirect&bpo=44839]: MemoryError raised in user-defined functions will now produce a MemoryError in sqlite3. OverflowError will now be converted to DataError. Previously OperationalError was produced in these cases.

bpo-44822 [https://bugs.python.org/issue?@action=redirect&bpo=44822]: sqlite3 user-defined functions and aggregators returning strings with embedded NUL characters are no longer truncated. Patch by Erlend E. Aasland.

bpo-44801 [https://bugs.python.org/issue?@action=redirect&bpo=44801]: Ensure that the ParamSpec variable in Callable can only be substituted with a parameters expression (a list of types, an ellipsis, ParamSpec or Concatenate).

bpo-44806 [https://bugs.python.org/issue?@action=redirect&bpo=44806]: Non-protocol subclasses of typing.Protocol ignore now the __init__ method inherited from protocol base classes.

bpo-27275 [https://bugs.python.org/issue?@action=redirect&bpo=27275]: collections.OrderedDict.popitem() and collections.OrderedDict.pop() no longer call __getitem__ and __delitem__ methods of the OrderedDict subclasses.

bpo-44793 [https://bugs.python.org/issue?@action=redirect&bpo=44793]: Fix checking the number of arguments when subscribe a generic type with ParamSpec parameter.

bpo-44784 [https://bugs.python.org/issue?@action=redirect&bpo=44784]: In importlib.metadata tests, override warnings behavior under expected DeprecationWarnings (importlib_metadata 4.6.3).

bpo-44667 [https://bugs.python.org/issue?@action=redirect&bpo=44667]: The tokenize.tokenize() doesn’t incorrectly generate a NEWLINE token if the source doesn’t end with a new line character but the last line is a comment, as the function is already generating a NL token. Patch by Pablo Galindo

bpo-44771 [https://bugs.python.org/issue?@action=redirect&bpo=44771]: Added importlib.simple module implementing adapters from a low-level resources reader interface to a TraversableResources interface. Legacy API (path, contents, …) is now supported entirely by the .files() API with a compatibility shim supplied for resource loaders without that functionality. Feature parity with importlib_resources 5.2.

bpo-44752 [https://bugs.python.org/issue?@action=redirect&bpo=44752]: rcompleter does not call getattr() on property objects to avoid the side-effect of evaluating the corresponding method.

bpo-44747 [https://bugs.python.org/issue?@action=redirect&bpo=44747]: Refactor usage of sys._getframe in typing module. Patch provided by Yurii Karabas.

bpo-42378 [https://bugs.python.org/issue?@action=redirect&bpo=42378]: Fixes the issue with log file being overwritten when logging.FileHandler is used in atexit with filemode set to 'w'. Note this will cause the message in atexit not being logged if the log stream is already closed due to shutdown of logging.

bpo-44720 [https://bugs.python.org/issue?@action=redirect&bpo=44720]: weakref.proxy objects referencing non-iterators now raise TypeError rather than dereferencing the null tp_iternext slot and crashing.

bpo-44704 [https://bugs.python.org/issue?@action=redirect&bpo=44704]: The implementation of collections.abc.Set._hash() now matches that of frozenset.__hash__().

bpo-44666 [https://bugs.python.org/issue?@action=redirect&bpo=44666]: Fixed issue in compileall.compile_file() when sys.stdout is redirected. Patch by Stefan Hölzl.

bpo-44688 [https://bugs.python.org/issue?@action=redirect&bpo=44688]: sqlite3.Connection.create_collation() now accepts non-ASCII collation names. Patch by Erlend E. Aasland.

bpo-44690 [https://bugs.python.org/issue?@action=redirect&bpo=44690]: Adopt binacii.a2b_base64’s strict mode in base64.b64decode.

bpo-42854 [https://bugs.python.org/issue?@action=redirect&bpo=42854]: Fixed a bug in the _ssl module that was throwing OverflowError when using _ssl._SSLSocket.write() and _ssl._SSLSocket.read() for a big value of the len parameter. Patch by Pablo Galindo.

bpo-44686 [https://bugs.python.org/issue?@action=redirect&bpo=44686]: Replace unittest.mock._importer with pkgutil.resolve_name.

bpo-44353 [https://bugs.python.org/issue?@action=redirect&bpo=44353]: Make NewType.__call__ faster by implementing it in C. Patch provided by Yurii Karabas.

bpo-44682 [https://bugs.python.org/issue?@action=redirect&bpo=44682]: Change the pdb commands directive to disallow setting commands for an invalid breakpoint and to display an appropriate error.

bpo-44353 [https://bugs.python.org/issue?@action=redirect&bpo=44353]: Refactor typing.NewType from function into callable class. Patch provided by Yurii Karabas.

bpo-44678 [https://bugs.python.org/issue?@action=redirect&bpo=44678]: Added a separate error message for discontinuous padding in binascii.a2b_base64 strict mode.

bpo-44524 [https://bugs.python.org/issue?@action=redirect&bpo=44524]: Add missing __name__ and __qualname__ attributes to typing module classes. Patch provided by Yurii Karabas.

bpo-40897 [https://bugs.python.org/issue?@action=redirect&bpo=40897]: Give priority to using the current class constructor in inspect.signature(). Patch by Weipeng Hong.

bpo-44638 [https://bugs.python.org/issue?@action=redirect&bpo=44638]: Add a reference to the zipp project and hint as to how to use it.

bpo-44648 [https://bugs.python.org/issue?@action=redirect&bpo=44648]: Fixed wrong error being thrown by inspect.getsource() when examining a class in the interactive session. Instead of TypeError, it should be OSError with appropriate error message.

bpo-44608 [https://bugs.python.org/issue?@action=redirect&bpo=44608]: Fix memory leak in _tkinter._flatten() if it is called with a sequence or set, but not list or tuple.

bpo-44594 [https://bugs.python.org/issue?@action=redirect&bpo=44594]: Fix an edge case of ExitStack and AsyncExitStack exception chaining. They will now match with block behavior when __context__ is explicitly set to None when the exception is in flight.

bpo-42799 [https://bugs.python.org/issue?@action=redirect&bpo=42799]: In fnmatch, the cache size for compiled regex patterns (functools.lru_cache()) was bumped up from 256 to 32768, affecting functions: fnmatch.fnmatch(), fnmatch.fnmatchcase(), fnmatch.filter().

bpo-41928 [https://bugs.python.org/issue?@action=redirect&bpo=41928]: Update shutil.copyfile() to raise FileNotFoundError instead of confusing IsADirectoryError when a path ending with a os.path.sep does not exist; shutil.copy() and shutil.copy2() are also affected.

bpo-44569 [https://bugs.python.org/issue?@action=redirect&bpo=44569]: Added the StackSummary.format_frame() function in traceback. This allows users to customize the way individual lines are formatted in tracebacks without re-implementing logic to handle recursive tracebacks.

bpo-44566 [https://bugs.python.org/issue?@action=redirect&bpo=44566]: handle StopIteration subclass raised from @contextlib.contextmanager generator

bpo-44558 [https://bugs.python.org/issue?@action=redirect&bpo=44558]: Make the implementation consistency of indexOf() between C and Python versions. Patch by Donghee Na.

bpo-41249 [https://bugs.python.org/issue?@action=redirect&bpo=41249]: Fixes TypedDict to work with typing.get_type_hints() and postponed evaluation of annotations across modules.

bpo-44554 [https://bugs.python.org/issue?@action=redirect&bpo=44554]: Refactor argument processing in pdb.main() to simplify detection of errors in input loading and clarify behavior around module or script invocation.

bpo-34798 [https://bugs.python.org/issue?@action=redirect&bpo=34798]: Break up paragraph about pprint.PrettyPrinter construction parameters to make it easier to read.

bpo-44539 [https://bugs.python.org/issue?@action=redirect&bpo=44539]: Added support for recognizing JPEG files without JFIF or Exif markers.

bpo-44461 [https://bugs.python.org/issue?@action=redirect&bpo=44461]: Fix bug with pdb’s handling of import error due to a package which does not have a __main__ module

bpo-43625 [https://bugs.python.org/issue?@action=redirect&bpo=43625]: Fix a bug in the detection of CSV file headers by csv.Sniffer.has_header() and improve documentation of same.

bpo-44516 [https://bugs.python.org/issue?@action=redirect&bpo=44516]: Update vendored pip to 21.1.3

bpo-42892 [https://bugs.python.org/issue?@action=redirect&bpo=42892]: Fixed an exception thrown while parsing a malformed multipart email by email.message.EmailMessage.

bpo-44468 [https://bugs.python.org/issue?@action=redirect&bpo=44468]: typing.get_type_hints() now finds annotations in classes and base classes with unexpected __module__. Previously, it skipped those MRO elements.

bpo-44491 [https://bugs.python.org/issue?@action=redirect&bpo=44491]: Allow clearing the sqlite3 authorizer callback by passing None to set_authorizer(). Patch by Erlend E. Aasland.

bpo-43977 [https://bugs.python.org/issue?@action=redirect&bpo=43977]: Set the proper Py_TPFLAGS_MAPPING and Py_TPFLAGS_SEQUENCE flags for subclasses created before a parent has been registered as a collections.abc.Mapping or collections.abc.Sequence.

bpo-44482 [https://bugs.python.org/issue?@action=redirect&bpo=44482]: Fix very unlikely resource leak in glob in alternate Python implementations.

bpo-44466 [https://bugs.python.org/issue?@action=redirect&bpo=44466]: The faulthandler module now detects if a fatal error occurs during a garbage collector collection. Patch by Victor Stinner.

bpo-44471 [https://bugs.python.org/issue?@action=redirect&bpo=44471]: A TypeError is now raised instead of an AttributeError in contextlib.ExitStack.enter_context() and contextlib.AsyncExitStack.enter_async_context() for objects which do not support the context manager or asynchronous context manager protocols correspondingly.

bpo-44404 [https://bugs.python.org/issue?@action=redirect&bpo=44404]: tkinter’s after() method now supports callables without the __name__ attribute.

bpo-41546 [https://bugs.python.org/issue?@action=redirect&bpo=41546]: Make pprint (like the builtin print) not attempt to write to stdout when it is None.

bpo-44458 [https://bugs.python.org/issue?@action=redirect&bpo=44458]: BUFFER_BLOCK_SIZE is now declared static, to avoid linking collisions when bz2, lmza or zlib are statically linked.

bpo-44464 [https://bugs.python.org/issue?@action=redirect&bpo=44464]: Remove exception for flake8 in deprecated importlib.metadata interfaces. Sync with importlib_metadata 4.6.

bpo-44446 [https://bugs.python.org/issue?@action=redirect&bpo=44446]: Take into account that lineno might be None in traceback.FrameSummary.

bpo-44439 [https://bugs.python.org/issue?@action=redirect&bpo=44439]: Fix in bz2.BZ2File.write() / lzma.LZMAFile.write() methods, when the input data is an object that supports the buffer protocol, the file length may be wrong.

bpo-44434 [https://bugs.python.org/issue?@action=redirect&bpo=44434]: _thread.start_new_thread() no longer calls PyThread_exit_thread() explicitly at the thread exit, the call was redundant. On Linux with the glibc, pthread_exit() aborts the whole process if dlopen() fails to open libgcc_s.so file (ex: EMFILE error). Patch by Victor Stinner.

bpo-42972 [https://bugs.python.org/issue?@action=redirect&bpo=42972]: The _thread.RLock type now fully implement the GC protocol: add a traverse function and the Py_TPFLAGS_HAVE_GC flag. Patch by Victor Stinner.

bpo-44422 [https://bugs.python.org/issue?@action=redirect&bpo=44422]: The threading.enumerate() function now uses a reentrant lock to prevent a hang on reentrant call. Patch by Victor Stinner.

bpo-38291 [https://bugs.python.org/issue?@action=redirect&bpo=38291]: Importing typing.io or typing.re now prints a DeprecationWarning.

bpo-37880 [https://bugs.python.org/issue?@action=redirect&bpo=37880]: argparse actions store_const and append_const each receive a default value of None when the const kwarg is not provided. Previously, this raised a TypeError.

bpo-44389 [https://bugs.python.org/issue?@action=redirect&bpo=44389]: Fix deprecation of ssl.OP_NO_TLSv1_3

bpo-27827 [https://bugs.python.org/issue?@action=redirect&bpo=27827]: pathlib.PureWindowsPath.is_reserved() now identifies a greater range of reserved filenames, including those with trailing spaces or colons.

bpo-44395 [https://bugs.python.org/issue?@action=redirect&bpo=44395]: Fix as_string() to pass unixfrom properly. Patch by Donghee Na.

bpo-34266 [https://bugs.python.org/issue?@action=redirect&bpo=34266]: Handle exceptions from parsing the arg of pdb’s run/restart command.

bpo-44362 [https://bugs.python.org/issue?@action=redirect&bpo=44362]: Improve ssl module’s deprecation messages, error reporting, and documentation for deprecations.

bpo-44342 [https://bugs.python.org/issue?@action=redirect&bpo=44342]: [Enum] Change pickling from by-value to by-name.

bpo-44356 [https://bugs.python.org/issue?@action=redirect&bpo=44356]: [Enum] Allow multiple data-type mixins if they are all the same.

bpo-44351 [https://bugs.python.org/issue?@action=redirect&bpo=44351]: Restore back parse_makefile() in distutils.sysconfig because it behaves differently than the similar implementation in sysconfig.

bpo-35800 [https://bugs.python.org/issue?@action=redirect&bpo=35800]: smtpd.MailmanProxy is now removed as it is unusable without an external module, mailman. Patch by Donghee Na.

bpo-44357 [https://bugs.python.org/issue?@action=redirect&bpo=44357]: Added a function that returns cube root of the given number math.cbrt()

bpo-44339 [https://bugs.python.org/issue?@action=redirect&bpo=44339]: Change math.pow(±0.0, -math.inf) to return inf instead of raising ValueError. This brings the special-case handling of math.pow into compliance with the IEEE 754 standard.

bpo-44242 [https://bugs.python.org/issue?@action=redirect&bpo=44242]: Remove missing flag check from Enum creation and move into a verify decorator.

bpo-44246 [https://bugs.python.org/issue?@action=redirect&bpo=44246]: In importlib.metadata, restore compatibility in the result from Distribution.entry_points (EntryPoints) to honor expectations in older implementations and issuing deprecation warnings for these cases: A. EntryPoints objects are once again mutable, allowing for sort() and other list-based mutation operations. Avoid deprecation warnings by casting to a mutable sequence (e.g. list(dist.entry_points).sort()). B. EntryPoints results once again allow for access by index. To avoid deprecation warnings, cast the result to a Sequence first (e.g. tuple(dist.entry_points)[0]).

bpo-44246 [https://bugs.python.org/issue?@action=redirect&bpo=44246]: In importlib.metadata.entry_points, de-duplication of distributions no longer requires loading the full metadata for PathDistribution objects, improving entry point loading performance by ~10x.

bpo-43858 [https://bugs.python.org/issue?@action=redirect&bpo=43858]: Added a function that returns a copy of a dict of logging levels: logging.getLevelNamesMapping()

bpo-44260 [https://bugs.python.org/issue?@action=redirect&bpo=44260]: The random.Random constructor no longer reads system entropy without need.

bpo-44254 [https://bugs.python.org/issue?@action=redirect&bpo=44254]: On Mac, give turtledemo button text a color that works on both light or dark background. Programmers cannot control the latter.

bpo-44258 [https://bugs.python.org/issue?@action=redirect&bpo=44258]: Support PEP 515 for Fraction’s initialization from string.

bpo-44235 [https://bugs.python.org/issue?@action=redirect&bpo=44235]: Remove deprecated functions in the gettext. Patch by Donghee Na.

bpo-38693 [https://bugs.python.org/issue?@action=redirect&bpo=38693]: Prefer f-strings to .format in importlib.resources.

bpo-33693 [https://bugs.python.org/issue?@action=redirect&bpo=33693]: Importlib.metadata now prefers f-strings to .format.

bpo-44241 [https://bugs.python.org/issue?@action=redirect&bpo=44241]: Incorporate minor tweaks from importlib_metadata 4.1: SimplePath protocol, support for Metadata 2.2.

bpo-43216 [https://bugs.python.org/issue?@action=redirect&bpo=43216]: Remove the @asyncio.coroutine decorator enabling legacy generator-based coroutines to be compatible with async/await code; remove asyncio.coroutines.CoroWrapper used for wrapping legacy coroutine objects in the debug mode. The decorator has been deprecated since Python 3.8 and the removal was initially scheduled for Python 3.10. Patch by Illia Volochii.

bpo-44210 [https://bugs.python.org/issue?@action=redirect&bpo=44210]: Make importlib.metadata._meta.PackageMetadata public.

bpo-43643 [https://bugs.python.org/issue?@action=redirect&bpo=43643]: Declare readers.MultiplexedPath.name as a property per the spec.

bpo-27334 [https://bugs.python.org/issue?@action=redirect&bpo=27334]: The sqlite3 context manager now performs a rollback (thus releasing the database lock) if commit failed. Patch by Luca Citi and Erlend E. Aasland.

bpo-4928 [https://bugs.python.org/issue?@action=redirect&bpo=4928]: Documented existing behavior on POSIX: NamedTemporaryFiles are not deleted when creating process is killed with SIGKILL

bpo-44154 [https://bugs.python.org/issue?@action=redirect&bpo=44154]: Optimize fractions.Fraction pickling for large components.

bpo-33433 [https://bugs.python.org/issue?@action=redirect&bpo=33433]: For IPv4 mapped IPv6 addresses (RFC 4291 [https://datatracker.ietf.org/doc/html/rfc4291.html] Section 2.5.5.2), the ipaddress.IPv6Address.is_private check is deferred to the mapped IPv4 address. This solves a bug where public mapped IPv4 addresses were considered private by the IPv6 check.

bpo-44150 [https://bugs.python.org/issue?@action=redirect&bpo=44150]: Add optional weights argument to statistics.fmean().

bpo-44142 [https://bugs.python.org/issue?@action=redirect&bpo=44142]: ast.unparse() will now drop the redundant parentheses when tuples used as assignment targets (e.g in for loops).

bpo-44145 [https://bugs.python.org/issue?@action=redirect&bpo=44145]: hmac computations were not releasing the GIL while calling the OpenSSL HMAC_Update C API (a new feature in 3.9). This unintentionally prevented parallel computation as other hashlib algorithms support.

bpo-44095 [https://bugs.python.org/issue?@action=redirect&bpo=44095]: zipfile.Path now supports zipfile.Path.stem, zipfile.Path.suffixes, and zipfile.Path.suffix attributes.

bpo-44077 [https://bugs.python.org/issue?@action=redirect&bpo=44077]: It’s now possible to receive the type of service (ToS), a.k.a. differentiated services (DS), a.k.a. differentiated services code point (DSCP) and explicit congestion notification (ECN) IP header fields with socket.IP_RECVTOS.

bpo-37788 [https://bugs.python.org/issue?@action=redirect&bpo=37788]: Fix a reference leak when a Thread object is never joined.

bpo-38908 [https://bugs.python.org/issue?@action=redirect&bpo=38908]: Subclasses of typing.Protocol which only have data variables declared will now raise a TypeError when checked with isinstance unless they are decorated with runtime_checkable(). Previously, these checks passed silently. Patch provided by Yurii Karabas.

bpo-44098 [https://bugs.python.org/issue?@action=redirect&bpo=44098]: typing.ParamSpec will no longer be found in the __parameters__ of most typing generics except in valid use locations specified by PEP 612 [https://peps.python.org/pep-0612/]. This prevents incorrect usage like typing.List[P][int]. This change means incorrect usage which may have passed silently in 3.10 beta 1 and earlier will now error.

bpo-44089 [https://bugs.python.org/issue?@action=redirect&bpo=44089]: Allow subclassing csv.Error in 3.10 (it was allowed in 3.9 and earlier but was disallowed in early versions of 3.10).

bpo-44081 [https://bugs.python.org/issue?@action=redirect&bpo=44081]: ast.unparse() now doesn’t use redundant spaces to separate lambda and the : if there are no parameters.

bpo-44061 [https://bugs.python.org/issue?@action=redirect&bpo=44061]: Fix regression in previous release when calling pkgutil.iter_modules() with a list of pathlib.Path objects

bpo-44059 [https://bugs.python.org/issue?@action=redirect&bpo=44059]: Register the SerenityOS Browser in the webbrowser module.

bpo-36515 [https://bugs.python.org/issue?@action=redirect&bpo=36515]: The hashlib module no longer does unaligned memory accesses when compiled for ARM platforms.

bpo-40465 [https://bugs.python.org/issue?@action=redirect&bpo=40465]: Remove random module features deprecated in Python 3.9.

bpo-44018 [https://bugs.python.org/issue?@action=redirect&bpo=44018]: random.seed() no longer mutates bytearray inputs.

bpo-38352 [https://bugs.python.org/issue?@action=redirect&bpo=38352]: Add IO, BinaryIO, TextIO, Match, and Pattern to typing.__all__. Patch by Jelle Zijlstra.

bpo-44002 [https://bugs.python.org/issue?@action=redirect&bpo=44002]: urllib.parse now uses functool.lru_cache() for its internal URL splitting and quoting caches instead of rolling its own like its the ‘90s.

The undocumented internal urllib.parse Quoted class API is now deprecated, for removal in 3.14.

bpo-43972 [https://bugs.python.org/issue?@action=redirect&bpo=43972]: When http.server.SimpleHTTPRequestHandler sends a 301 (Moved Permanently) for a directory path not ending with /, add a Content-Length: 0 header. This improves the behavior for certain clients.

bpo-28528 [https://bugs.python.org/issue?@action=redirect&bpo=28528]: Fix a bug in pdb where checkline() raises AttributeError if it is called after reset().

bpo-43853 [https://bugs.python.org/issue?@action=redirect&bpo=43853]: Improved string handling for sqlite3 user-defined functions and aggregates:

It is now possible to pass strings with embedded null characters to UDFs

Conversion failures now correctly raise MemoryError

Patch by Erlend E. Aasland.

bpo-43666 [https://bugs.python.org/issue?@action=redirect&bpo=43666]: AIX: Lib/_aix_support.get_platform() may fail in an AIX WPAR. The fileset bos.rte appears to have a builddate in both LPAR and WPAR so this fileset is queried rather than bos.mp64. To prevent a similar situation (no builddate in ODM) a value (9988) sufficient for completing a build is provided. Patch by M Felt.

bpo-43650 [https://bugs.python.org/issue?@action=redirect&bpo=43650]: Fix MemoryError in shutil.unpack_archive() which fails inside shutil._unpack_zipfile() on large files. Patch by Igor Bolshakov.

bpo-43612 [https://bugs.python.org/issue?@action=redirect&bpo=43612]: zlib.compress() now accepts a wbits parameter which allows users to compress data as a raw deflate block without zlib headers and trailers in one go. Previously this required instantiating a zlib.compressobj. It also provides a faster alternative to gzip.compress when wbits=31 is used.

bpo-43392 [https://bugs.python.org/issue?@action=redirect&bpo=43392]: importlib._bootstrap._find_and_load() now implements a two-step check to avoid locking when modules have been already imported and are ready. This improves performance of repeated calls to importlib.import_module() and importlib.__import__().

bpo-43318 [https://bugs.python.org/issue?@action=redirect&bpo=43318]: Fix a bug where pdb does not always echo cleared breakpoints.

bpo-43234 [https://bugs.python.org/issue?@action=redirect&bpo=43234]: Prohibit passing non-concurrent.futures.ThreadPoolExecutor executors to loop.set_default_executor() following a deprecation in Python 3.8. Patch by Illia Volochii.

bpo-43232 [https://bugs.python.org/issue?@action=redirect&bpo=43232]: Prohibit previously deprecated potentially disruptive operations on asyncio.trsock.TransportSocket. Patch by Illia Volochii.

bpo-30077 [https://bugs.python.org/issue?@action=redirect&bpo=30077]: Added support for Apple’s aifc/sowt pseudo-compression

bpo-42971 [https://bugs.python.org/issue?@action=redirect&bpo=42971]: Add definition of errno.EQFULL for platforms that define this constant (such as macOS).

bpo-43086 [https://bugs.python.org/issue?@action=redirect&bpo=43086]: Added a new optional strict_mode parameter to binascii.a2b_base64. When scrict_mode is set to True, the a2b_base64 function will accept only valid base64 content. More details about what “valid base64 content” is, can be found in the function’s documentation.

bpo-43024 [https://bugs.python.org/issue?@action=redirect&bpo=43024]: Improve the help signature of traceback.print_exception(), traceback.format_exception() and traceback.format_exception_only().

bpo-33809 [https://bugs.python.org/issue?@action=redirect&bpo=33809]: Add the traceback.TracebackException.print() method which prints the formatted exception information.

bpo-42862 [https://bugs.python.org/issue?@action=redirect&bpo=42862]: sqlite3 now utilizes functools.lru_cache() to implement the connection statement cache. As a small optimisation, the default statement cache size has been increased from 100 to 128. Patch by Erlend E. Aasland.

bpo-41818 [https://bugs.python.org/issue?@action=redirect&bpo=41818]: Soumendra Ganguly: add termios.tcgetwinsize(), termios.tcsetwinsize().

bpo-40497 [https://bugs.python.org/issue?@action=redirect&bpo=40497]: subprocess.check_output() now raises ValueError when the invalid keyword argument check is passed by user code. Previously such use would fail later with a TypeError. Patch by Rémi Lapeyre.

bpo-37449 [https://bugs.python.org/issue?@action=redirect&bpo=37449]: ensurepip now uses importlib.resources.files() traversable APIs

bpo-40956 [https://bugs.python.org/issue?@action=redirect&bpo=40956]: Use Argument Clinic in sqlite3. Patches by Erlend E. Aasland.

bpo-41730 [https://bugs.python.org/issue?@action=redirect&bpo=41730]: DeprecationWarning is now raised when importing tkinter.tix, which has been deprecated in documentation since Python 3.6.

bpo-20684 [https://bugs.python.org/issue?@action=redirect&bpo=20684]: Remove unused _signature_get_bound_param function from inspect - by Anthony Sottile.

bpo-41402 [https://bugs.python.org/issue?@action=redirect&bpo=41402]: Fix email.message.EmailMessage.set_content() when called with binary data and 7bit content transfer encoding.

bpo-32695 [https://bugs.python.org/issue?@action=redirect&bpo=32695]: The compresslevel and preset keyword arguments of tarfile.open() are now both documented and tested.

bpo-41137 [https://bugs.python.org/issue?@action=redirect&bpo=41137]: Use utf-8 encoding while reading .pdbrc files. Patch by Srinivas Reddy Thatiparthy

bpo-24391 [https://bugs.python.org/issue?@action=redirect&bpo=24391]: Improved reprs of threading synchronization objects: Semaphore, BoundedSemaphore, Event and Barrier.

bpo-5846 [https://bugs.python.org/issue?@action=redirect&bpo=5846]: Deprecated the following unittest functions, scheduled for removal in Python 3.13:

findTestCases()

makeSuite()

getTestCaseNames()

Use TestLoader methods instead:

unittest.TestLoader.loadTestsFromModule()

unittest.TestLoader.loadTestsFromTestCase()

unittest.TestLoader.getTestCaseNames()

Patch by Erlend E. Aasland.

bpo-40563 [https://bugs.python.org/issue?@action=redirect&bpo=40563]: Support pathlike objects on dbm/shelve. Patch by Hakan Çelik and Henry-Joseph Audéoud.

bpo-34990 [https://bugs.python.org/issue?@action=redirect&bpo=34990]: Fixed a Y2k38 bug in the compileall module where it would fail to compile files with a modification time after the year 2038.

bpo-39549 [https://bugs.python.org/issue?@action=redirect&bpo=39549]: Whereas the code for reprlib.Repr had previously used a hardcoded string value of ‘…’, this PR updates it to use of a “fillvalue” attribute, whose value defaults to ‘…’ and can be reset in either individual reprlib.Repr instances or in subclasses thereof.

bpo-37022 [https://bugs.python.org/issue?@action=redirect&bpo=37022]: pdb now displays exceptions from repr() with its p and pp commands.

bpo-38840 [https://bugs.python.org/issue?@action=redirect&bpo=38840]: Fix test___all__ on platforms lacking a shared memory implementation.

bpo-39359 [https://bugs.python.org/issue?@action=redirect&bpo=39359]: Add one missing check that the password is a bytes object for an encrypted zipfile.

bpo-38741 [https://bugs.python.org/issue?@action=redirect&bpo=38741]: configparser: using ‘]’ inside a section header will no longer cut the section name short at the ‘]’

bpo-38415 [https://bugs.python.org/issue?@action=redirect&bpo=38415]: Added missing behavior to contextlib.asynccontextmanager() to match contextlib.contextmanager() so decorated functions can themselves be decorators.

bpo-30256 [https://bugs.python.org/issue?@action=redirect&bpo=30256]: Pass multiprocessing BaseProxy argument manager_owned through AutoProxy.

bpo-27513 [https://bugs.python.org/issue?@action=redirect&bpo=27513]: email.utils.getaddresses() now accepts email.header.Header objects along with string values. Patch by Zackery Spytz.

bpo-16379 [https://bugs.python.org/issue?@action=redirect&bpo=16379]: Add SQLite error code and name to sqlite3 exceptions. Patch by Aviv Palivoda, Daniel Shahaf, and Erlend E. Aasland.

bpo-26228 [https://bugs.python.org/issue?@action=redirect&bpo=26228]: pty.spawn no longer hangs on FreeBSD, macOS, and Solaris.

bpo-33349 [https://bugs.python.org/issue?@action=redirect&bpo=33349]: lib2to3 now recognizes async generators everywhere.

bpo-29298 [https://bugs.python.org/issue?@action=redirect&bpo=29298]: Fix TypeError when required subparsers without dest do not receive arguments. Patch by Anthony Sottile.

Documentation

bpo-45216 [https://bugs.python.org/issue?@action=redirect&bpo=45216]: Remove extra documentation listing methods in difflib. It was rendering twice in pydoc and was outdated in some places.

bpo-45024 [https://bugs.python.org/issue?@action=redirect&bpo=45024]: collections.abc documentation has been expanded to explicitly cover how instance and subclass checks work, with additional doctest examples and an exhaustive list of ABCs which test membership purely by presence of the right special methods. Patch by Raymond Hettinger.

bpo-44957 [https://bugs.python.org/issue?@action=redirect&bpo=44957]: Promote PEP 604 union syntax by using it where possible. Also, mention X | Y more prominently in section about Union and mention X | None at all in section about Optional.

bpo-16580 [https://bugs.python.org/issue?@action=redirect&bpo=16580]: Added code equivalents for the int.to_bytes() and int.from_bytes() methods, as well as tests ensuring that these code equivalents are valid.

bpo-44903 [https://bugs.python.org/issue?@action=redirect&bpo=44903]: Removed the othergui.rst file, any references to it, and the list of GUI frameworks in the FAQ. In their place I’ve added links to the Python Wiki page on GUI frameworks [https://wiki.python.org/moin/GuiProgramming].

bpo-33479 [https://bugs.python.org/issue?@action=redirect&bpo=33479]: Tkinter documentation has been greatly expanded with new “Architecture” and “Threading model” sections.

bpo-36700 [https://bugs.python.org/issue?@action=redirect&bpo=36700]: base64 RFC references were updated to point to RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html]; a section was added to point users to the new “security considerations” section of the RFC.

bpo-44740 [https://bugs.python.org/issue?@action=redirect&bpo=44740]: Replaced occurrences of uppercase “Web” and “Internet” with lowercase versions per the 2016 revised Associated Press Style Book.

bpo-44693 [https://bugs.python.org/issue?@action=redirect&bpo=44693]: Update the definition of __future__ in the glossary by replacing the confusing word “pseudo-module” with a more accurate description.

bpo-35183 [https://bugs.python.org/issue?@action=redirect&bpo=35183]: Add typical examples to os.path.splitext docs

bpo-30511 [https://bugs.python.org/issue?@action=redirect&bpo=30511]: Clarify that shutil.make_archive() is not thread-safe due to reliance on changing the current working directory.

bpo-44561 [https://bugs.python.org/issue?@action=redirect&bpo=44561]: Update of three expired hyperlinks in Doc/distributing/index.rst: “Project structure”, “Building and packaging the project”, and “Uploading the project to the Python Packaging Index”.

bpo-44651 [https://bugs.python.org/issue?@action=redirect&bpo=44651]: Delete entry “coercion” in Doc/glossary.rst for its outdated definition.

bpo-42958 [https://bugs.python.org/issue?@action=redirect&bpo=42958]: Updated the docstring and docs of filecmp.cmp() to be more accurate and less confusing especially in respect to shallow arg.

bpo-44631 [https://bugs.python.org/issue?@action=redirect&bpo=44631]: Refactored the repr() code of the _Environ (os module).

bpo-44613 [https://bugs.python.org/issue?@action=redirect&bpo=44613]: importlib.metadata is no longer provisional.

bpo-44558 [https://bugs.python.org/issue?@action=redirect&bpo=44558]: Match the docstring and python implementation of countOf() to the behavior of its c implementation.

bpo-44544 [https://bugs.python.org/issue?@action=redirect&bpo=44544]: List all kwargs for textwrap.wrap(), textwrap.fill(), and textwrap.shorten(). Now, there are nav links to attributes of TextWrap, which makes navigation much easier while minimizing duplication in the documentation.

bpo-38062 [https://bugs.python.org/issue?@action=redirect&bpo=38062]: Clarify that atexit uses equality comparisons internally.

bpo-40620 [https://bugs.python.org/issue?@action=redirect&bpo=40620]: Convert examples in tutorial controlflow.rst section 4.3 to be interpreter-demo style.

bpo-43066 [https://bugs.python.org/issue?@action=redirect&bpo=43066]: Added a warning to zipfile docs: filename arg with a leading slash may cause archive to be un-openable on Windows systems.

bpo-39452 [https://bugs.python.org/issue?@action=redirect&bpo=39452]: Rewrote Doc/library/__main__.rst. Broadened scope of the document to explicitly discuss and differentiate between __main__.py in packages versus the __name__ == '__main__' expression (and the idioms that surround it).

bpo-13814 [https://bugs.python.org/issue?@action=redirect&bpo=13814]: In the Design FAQ, answer “Why don’t generators support the with statement?”

bpo-27752 [https://bugs.python.org/issue?@action=redirect&bpo=27752]: Documentation of csv.Dialect is more descriptive.

bpo-44453 [https://bugs.python.org/issue?@action=redirect&bpo=44453]: Fix documentation for the return type of sysconfig.get_path().

bpo-44392 [https://bugs.python.org/issue?@action=redirect&bpo=44392]: Added a new section in the C API documentation for types used in type hinting. Documented Py_GenericAlias and Py_GenericAliasType.

bpo-38291 [https://bugs.python.org/issue?@action=redirect&bpo=38291]: Mark typing.io and typing.re as deprecated since Python 3.8 in the documentation. They were never properly supported by type checkers.

bpo-44322 [https://bugs.python.org/issue?@action=redirect&bpo=44322]: Document that SyntaxError args have a details tuple and that details are adjusted for errors in f-string field replacement expressions.

bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392]: Document the deprecation and removal of the loop parameter for many functions and classes in asyncio.

bpo-44195 [https://bugs.python.org/issue?@action=redirect&bpo=44195]: Corrected references to TraversableResources in docs. There is no TraversableReader.

bpo-41963 [https://bugs.python.org/issue?@action=redirect&bpo=41963]: Document that ConfigParser strips off comments when reading configuration files.

bpo-44072 [https://bugs.python.org/issue?@action=redirect&bpo=44072]: Correct where in the numeric ABC hierarchy ** support is added, i.e., in numbers.Complex, not numbers.Integral.

bpo-43558 [https://bugs.python.org/issue?@action=redirect&bpo=43558]: Add the remark to dataclasses documentation that the __init__() of any base class has to be called in __post_init__(), along with a code example.

bpo-44025 [https://bugs.python.org/issue?@action=redirect&bpo=44025]: Clarify when ‘_’ in match statements is a keyword, and when not.

bpo-41706 [https://bugs.python.org/issue?@action=redirect&bpo=41706]: Fix docs about how methods like __add__ are invoked when evaluating operator expressions.

bpo-41621 [https://bugs.python.org/issue?@action=redirect&bpo=41621]: Document that collections.defaultdict parameter default_factory defaults to None and is positional-only.

bpo-41576 [https://bugs.python.org/issue?@action=redirect&bpo=41576]: document BaseException in favor of bare except

bpo-21760 [https://bugs.python.org/issue?@action=redirect&bpo=21760]: The description for __file__ fixed. Patch by Furkan Onder

bpo-39498 [https://bugs.python.org/issue?@action=redirect&bpo=39498]: Add a “Security Considerations” index which links to standard library modules that have explicitly documented security considerations.

bpo-33479 [https://bugs.python.org/issue?@action=redirect&bpo=33479]: Remove the unqualified claim that tkinter is threadsafe. It has not been true for several years and likely never was. An explanation of what is true may be added later, after more discussion, and possibly after patching _tkinter.c,

Tests

bpo-40173 [https://bugs.python.org/issue?@action=redirect&bpo=40173]: Fix test.support.import_helper.import_fresh_module().

bpo-45280 [https://bugs.python.org/issue?@action=redirect&bpo=45280]: Add a test case for empty typing.NamedTuple.

bpo-45269 [https://bugs.python.org/issue?@action=redirect&bpo=45269]: Cover case when invalid markers type is supplied to c_make_encoder.

bpo-45128 [https://bugs.python.org/issue?@action=redirect&bpo=45128]: Fix test_multiprocessing_fork failure due to test_logging and sys.modules manipulation.

bpo-45209 [https://bugs.python.org/issue?@action=redirect&bpo=45209]: Fix UserWarning: resource_tracker warning in _test_multiprocessing._TestSharedMemory.test_shared_memory_cleaned_after_process_termination

bpo-45185 [https://bugs.python.org/issue?@action=redirect&bpo=45185]: Enables TestEnumerations test cases in test_ssl suite.

bpo-45195 [https://bugs.python.org/issue?@action=redirect&bpo=45195]: Fix test_readline.test_nonascii(): sometimes, the newline character is not written at the end, so don’t expect it in the output. Patch by Victor Stinner.

bpo-45156 [https://bugs.python.org/issue?@action=redirect&bpo=45156]: Fixes infinite loop on unittest.mock.seal() of mocks created by create_autospec().

bpo-45125 [https://bugs.python.org/issue?@action=redirect&bpo=45125]: Improves pickling tests and docs of SharedMemory and SharableList objects.

bpo-44860 [https://bugs.python.org/issue?@action=redirect&bpo=44860]: Update test_sysconfig.test_user_similar() for the posix_user scheme: platlib doesn’t use sys.platlibdir. Patch by Victor Stinner.

bpo-45052 [https://bugs.python.org/issue?@action=redirect&bpo=45052]: WithProcessesTestSharedMemory.test_shared_memory_basics test was ignored, because self.assertEqual(sms.size, sms2.size) line was failing. It is now removed and test is unskipped.

The main motivation for this line to be removed from the test is that the size of SharedMemory is not ever guaranteed to be the same. It is decided by the platform.

bpo-44895 [https://bugs.python.org/issue?@action=redirect&bpo=44895]: libregrtest now clears the type cache later to reduce the risk of false alarm when checking for reference leaks. Previously, the type cache was cleared too early and libregrtest raised a false alarm about reference leaks under very specific conditions. Patch by Irit Katriel and Victor Stinner.

bpo-45042 [https://bugs.python.org/issue?@action=redirect&bpo=45042]: Fixes that test classes decorated with @hashlib_helper.requires_hashdigest were skipped all the time.

bpo-25130 [https://bugs.python.org/issue?@action=redirect&bpo=25130]: Add calls of gc.collect() in tests to support PyPy.

bpo-45011 [https://bugs.python.org/issue?@action=redirect&bpo=45011]: Made tests relying on the _asyncio C extension module optional to allow running on alternative Python implementations. Patch by Serhiy Storchaka.

bpo-44949 [https://bugs.python.org/issue?@action=redirect&bpo=44949]: Fix auto history tests of test_readline: sometimes, the newline character is not written at the end, so don’t expect it in the output.

bpo-44891 [https://bugs.python.org/issue?@action=redirect&bpo=44891]: Tests were added to clarify id() is preserved when obj * 1 is used on str and bytes objects. Patch by Nikita Sobolev.

bpo-44852 [https://bugs.python.org/issue?@action=redirect&bpo=44852]: Add ability to wholesale silence DeprecationWarnings while running the regression test suite.

bpo-40928 [https://bugs.python.org/issue?@action=redirect&bpo=40928]: Notify users running test_decimal regression tests on macOS of potential harmless “malloc can’t allocate region” messages spewed by test_decimal.

bpo-44734 [https://bugs.python.org/issue?@action=redirect&bpo=44734]: Fixed floating-point precision issue in turtle tests.

bpo-44708 [https://bugs.python.org/issue?@action=redirect&bpo=44708]: Regression tests, when run with -w, are now re-running only the affected test methods instead of re-running the entire test file.

bpo-42095 [https://bugs.python.org/issue?@action=redirect&bpo=42095]: Added interop tests for Apple plists: generate plist files with Python plistlib and parse with Apple plutil; and the other way round.

bpo-44647 [https://bugs.python.org/issue?@action=redirect&bpo=44647]: Added a permanent Unicode-valued environment variable to regression tests to ensure they handle this use case in the future. If your test environment breaks because of that, report a bug to us, and temporarily set PYTHONREGRTEST_UNICODE_GUARD=0 in your test environment.

bpo-44515 [https://bugs.python.org/issue?@action=redirect&bpo=44515]: Adjust recently added contextlib tests to avoid assuming the use of a refcounted GC

bpo-44287 [https://bugs.python.org/issue?@action=redirect&bpo=44287]: Fix asyncio test_popen() of test_windows_utils by using a longer timeout. Use military grade battle-tested test.support.SHORT_TIMEOUT timeout rather than a hardcoded timeout of 10 seconds: it’s 30 seconds by default, but it is made longer on slow buildbots. Patch by Victor Stinner.

bpo-44451 [https://bugs.python.org/issue?@action=redirect&bpo=44451]: Reset DeprecationWarning filters in test.test_importlib.test_metadata_api.APITests.test_entry_points_by_index to avoid StopIteration error if DeprecationWarnings are ignored.

bpo-44363 [https://bugs.python.org/issue?@action=redirect&bpo=44363]: Account for address sanitizer in test_capi. test_capi now passes when run GCC address sanitizer.

bpo-44364 [https://bugs.python.org/issue?@action=redirect&bpo=44364]: Add non integral tests for math.sqrt() function.

bpo-43921 [https://bugs.python.org/issue?@action=redirect&bpo=43921]: Fix test_ssl.test_wrong_cert_tls13(): use suppress_ragged_eofs=False, since read() can raise ssl.SSLEOFError on Windows. Patch by Victor Stinner.

bpo-43921 [https://bugs.python.org/issue?@action=redirect&bpo=43921]: Fix test_pha_required_nocert() of test_ssl: catch two more EOF cases (when the recv() method returns an empty string). Patch by Victor Stinner.

bpo-44131 [https://bugs.python.org/issue?@action=redirect&bpo=44131]: Add test_frozenmain to test_embed to test the Py_FrozenMain() C function. Patch by Victor Stinner.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Ignore error string case in test_file_not_exists().

bpo-42083 [https://bugs.python.org/issue?@action=redirect&bpo=42083]: Add test to check that PyStructSequence_NewType accepts a PyStructSequence_Desc with doc field set to NULL.

bpo-35753 [https://bugs.python.org/issue?@action=redirect&bpo=35753]: Fix crash in doctest when doctest parses modules that include unwrappable functions by skipping those functions.

bpo-30256 [https://bugs.python.org/issue?@action=redirect&bpo=30256]: Add test for nested queues when using multiprocessing shared objects AutoProxy[Queue] inside ListProxy and DictProxy

Build

bpo-45220 [https://bugs.python.org/issue?@action=redirect&bpo=45220]: Avoid building with the Windows 11 SDK previews automatically. This may be overridden by setting the DefaultWindowsSDKVersion environment variable before building.

bpo-45020 [https://bugs.python.org/issue?@action=redirect&bpo=45020]: Freeze stdlib modules that are imported during startup. This provides significant performance improvements to startup. If necessary, use the previously added “-X frozen_modules=off” commandline option to force importing the source modules.

bpo-45188 [https://bugs.python.org/issue?@action=redirect&bpo=45188]: Windows builds now regenerate frozen modules as the first part of the build. Previously the regeneration was later in the build, which would require it to be restarted if any modules had changed.

bpo-45163 [https://bugs.python.org/issue?@action=redirect&bpo=45163]: Fixes Haiku platform build.

bpo-45067 [https://bugs.python.org/issue?@action=redirect&bpo=45067]: The ncurses function extended_color_content was introduced in 2017

(https://invisible-island.net/ncurses/NEWS.html#index-t20170401). The

ncurses-devel package in CentOS 7 had a older version ncurses resulted in compilation error. For compiling ncurses with extended color support, we verify the version of the ncurses library >= 20170401.

bpo-45019 [https://bugs.python.org/issue?@action=redirect&bpo=45019]: Generate lines in relevant files for frozen modules. Up until now each of the files had to be edited manually. This change makes it easier to add to and modify the frozen modules.

bpo-44340 [https://bugs.python.org/issue?@action=redirect&bpo=44340]: Add support for building with clang thin lto via –with-lto=thin/full. Patch by Donghee Na and Brett Holman.

bpo-44535 [https://bugs.python.org/issue?@action=redirect&bpo=44535]: Enable building using a Visual Studio 2022 install on Windows.

bpo-43298 [https://bugs.python.org/issue?@action=redirect&bpo=43298]: Improved error message when building without a Windows SDK installed.

bpo-44381 [https://bugs.python.org/issue?@action=redirect&bpo=44381]: The Windows build now accepts EnableControlFlowGuard set to guard to enable CFG.

bpo-41282 [https://bugs.python.org/issue?@action=redirect&bpo=41282]: Fix broken make install that caused standard library extension modules to be unnecessarily and incorrectly rebuilt during the install phase of cpython.

Windows

bpo-45375 [https://bugs.python.org/issue?@action=redirect&bpo=45375]: Fixes an assertion failure due to searching for the standard library in unnormalised paths.

bpo-45022 [https://bugs.python.org/issue?@action=redirect&bpo=45022]: Update Windows release to include libffi 3.4.2

bpo-45007 [https://bugs.python.org/issue?@action=redirect&bpo=45007]: Update to OpenSSL 1.1.1l in Windows build

bpo-44848 [https://bugs.python.org/issue?@action=redirect&bpo=44848]: Upgrade Windows installer to use SQLite 3.36.0.

bpo-44572 [https://bugs.python.org/issue?@action=redirect&bpo=44572]: Avoid consuming standard input in the platform module

bpo-44582 [https://bugs.python.org/issue?@action=redirect&bpo=44582]: Accelerate speed of mimetypes initialization using a native implementation of the registry scan.

bpo-41299 [https://bugs.python.org/issue?@action=redirect&bpo=41299]: Fix 16 milliseconds jitter when using timeouts in threading, such as with threading.Lock.acquire() or threading.Condition.wait().

bpo-42686 [https://bugs.python.org/issue?@action=redirect&bpo=42686]: Build sqlite3 with math functions enabled. Patch by Erlend E. Aasland.

bpo-40263 [https://bugs.python.org/issue?@action=redirect&bpo=40263]: This is a follow-on bug from https://bugs.python.org/issue26903. Once that is applied we run into an off-by-one assertion problem. The assert was not correct.

macOS

bpo-45007 [https://bugs.python.org/issue?@action=redirect&bpo=45007]: Update macOS installer builds to use OpenSSL 1.1.1l.

bpo-34602 [https://bugs.python.org/issue?@action=redirect&bpo=34602]: When building CPython on macOS with ./configure --with-undefined-behavior-sanitizer --with-pydebug, the stack size is now quadrupled to allow for the entire test suite to pass.

bpo-44848 [https://bugs.python.org/issue?@action=redirect&bpo=44848]: Update macOS installer to use SQLite 3.36.0.

bpo-44689 [https://bugs.python.org/issue?@action=redirect&bpo=44689]: ctypes.util.find_library() now works correctly on macOS 11 Big Sur even if Python is built on an older version of macOS. Previously, when built on older macOS systems, find_library was not able to find macOS system libraries when running on Big Sur due to changes in how system libraries are stored.

bpo-41972 [https://bugs.python.org/issue?@action=redirect&bpo=41972]: The framework build’s user header path in sysconfig is changed to add a ‘pythonX.Y’ component to match distutils’s behavior.

bpo-43109 [https://bugs.python.org/issue?@action=redirect&bpo=43109]: Allow –with-lto configure option to work with Apple-supplied Xcode or Command Line Tools.

bpo-34932 [https://bugs.python.org/issue?@action=redirect&bpo=34932]: Add socket.TCP_KEEPALIVE support for macOS. Patch by Shane Harvey.

IDLE

bpo-45296 [https://bugs.python.org/issue?@action=redirect&bpo=45296]: On Windows, change exit/quit message to suggest Ctrl-D, which works, instead of <Ctrl-Z Return>, which does not work in IDLE.

bpo-45193 [https://bugs.python.org/issue?@action=redirect&bpo=45193]: Make completion boxes appear on Ubuntu again.

bpo-40128 [https://bugs.python.org/issue?@action=redirect&bpo=40128]: Mostly fix completions on macOS when not using tcl/tk 8.6.11 (as with 3.9). The added update_idletask call should be harmless and possibly helpful otherwise.

bpo-33962 [https://bugs.python.org/issue?@action=redirect&bpo=33962]: Move the indent space setting from the Font tab to the new Windows tab. Patch by Mark Roseman and Terry Jan Reedy.

bpo-40468 [https://bugs.python.org/issue?@action=redirect&bpo=40468]: Split the settings dialog General tab into Windows and Shell/ED tabs. Move help sources, which extend the Help menu, to the Extensions tab. Make space for new options and shorten the dialog. The latter makes the dialog better fit small screens.

bpo-41611 [https://bugs.python.org/issue?@action=redirect&bpo=41611]: Avoid uncaught exceptions in AutoCompleteWindow.winconfig_event().

bpo-41611 [https://bugs.python.org/issue?@action=redirect&bpo=41611]: Fix IDLE sometimes freezing upon tab-completion on macOS.

bpo-44010 [https://bugs.python.org/issue?@action=redirect&bpo=44010]: Highlight the new match statement’s soft keywords: match, case, and _. However, this highlighting is not perfect and will be incorrect in some rare cases, including some _-s in case patterns.

bpo-44026 [https://bugs.python.org/issue?@action=redirect&bpo=44026]: Include interpreter’s typo fix suggestions in message line for NameErrors and AttributeErrors. Patch by E. Paine.

Tools/Demos

bpo-44786 [https://bugs.python.org/issue?@action=redirect&bpo=44786]: Fix a warning in regular expression in the c-analyzer script.

bpo-44967 [https://bugs.python.org/issue?@action=redirect&bpo=44967]: pydoc now returns a non-zero status code when a module cannot be found.

bpo-44978 [https://bugs.python.org/issue?@action=redirect&bpo=44978]: Allow the Argument Clinic tool to handle __complex__ special methods.

bpo-43425 [https://bugs.python.org/issue?@action=redirect&bpo=43425]: Removed the ‘test2to3’ demo project that demonstrated using lib2to3 to support Python 2.x and Python 3.x from a single source in a distutils package. Patch by Donghee Na

bpo-44074 [https://bugs.python.org/issue?@action=redirect&bpo=44074]: Make patchcheck automatically detect the correct base branch name (previously it was hardcoded to ‘master’)

bpo-20291 [https://bugs.python.org/issue?@action=redirect&bpo=20291]: Added support for variadic positional parameters in Argument Clinic.

C API

bpo-41710 [https://bugs.python.org/issue?@action=redirect&bpo=41710]: The PyThread_acquire_lock_timed() function now clamps the timeout if it is too large, rather than aborting the process. Patch by Victor Stinner.

bpo-44687 [https://bugs.python.org/issue?@action=redirect&bpo=44687]: BufferedReader.peek() no longer raises ValueError when the entire file has already been buffered.

bpo-45116 [https://bugs.python.org/issue?@action=redirect&bpo=45116]: Add the Py_ALWAYS_INLINE macro to ask the compiler to always inline a static inline function. The compiler can ignore it and decides to not inline the function. Patch by Victor Stinner.

bpo-45094 [https://bugs.python.org/issue?@action=redirect&bpo=45094]: Add the Py_NO_INLINE macro to disable inlining on a function. Patch by Victor Stinner.

bpo-45061 [https://bugs.python.org/issue?@action=redirect&bpo=45061]: Add a deallocator to the bool type to detect refcount bugs in C extensions which call Py_DECREF(Py_True); or Py_DECREF(Py_False); by mistake. Patch by Victor Stinner.

bpo-42035 [https://bugs.python.org/issue?@action=redirect&bpo=42035]: Add a new PyType_GetQualName() function to get type’s qualified name.

bpo-41103 [https://bugs.python.org/issue?@action=redirect&bpo=41103]: Reverts removal of the old buffer protocol because they are part of stable ABI.

bpo-44751 [https://bugs.python.org/issue?@action=redirect&bpo=44751]: Remove crypt.h include from the public Python.h header.

bpo-42747 [https://bugs.python.org/issue?@action=redirect&bpo=42747]: The Py_TPFLAGS_HAVE_VERSION_TAG type flag now does nothing. The Py_TPFLAGS_HAVE_AM_SEND flag (which was added in 3.10) is removed. Both were unnecessary because it is not possible to have type objects with the relevant fields missing.

bpo-44530 [https://bugs.python.org/issue?@action=redirect&bpo=44530]: Added the co_qualname to the PyCodeObject structure to propagate the qualified name from the compiler to code objects.

Patch by Gabriele N. Tornetta

bpo-44441 [https://bugs.python.org/issue?@action=redirect&bpo=44441]: Py_RunMain() now resets PyImport_Inittab to its initial value at exit. It must be possible to call PyImport_AppendInittab() or PyImport_ExtendInittab() at each Python initialization. Patch by Victor Stinner.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Remove 4 private trashcan C API functions which were only kept for the backward compatibility of the stable ABI with Python 3.8 and older, since the trashcan API was not usable with the limited C API on Python 3.8 and older. The trashcan API was excluded from the limited C API in Python 3.9.

Removed functions:

_PyTrash_deposit_object()

_PyTrash_destroy_chain()

_PyTrash_thread_deposit_object()

_PyTrash_thread_destroy_chain()

The trashcan C API was never usable with the limited C API, since old trashcan macros accessed directly PyThreadState members like _tstate->trash_delete_nesting, whereas the PyThreadState structure is opaque in the limited C API.

Exclude also the PyTrash_UNWIND_LEVEL constant from the C API.

Patch by Victor Stinner.

bpo-40939 [https://bugs.python.org/issue?@action=redirect&bpo=40939]: Removed documentation for the removed PyParser_* C API.

bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795]: The list in Contents of Limited API now shows the public name PyFrameObject rather than _frame. The non-existing entry _node no longer appears in the list.

bpo-44378 [https://bugs.python.org/issue?@action=redirect&bpo=44378]: Py_IS_TYPE() no longer uses Py_TYPE() to avoid a compiler warning: no longer cast const PyObject* to PyObject*. Patch by Victor Stinner.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Convert the Py_TYPE() and Py_SIZE() macros to static inline functions. The Py_SET_TYPE() and Py_SET_SIZE() functions must now be used to set an object type and size. Patch by Victor Stinner.

bpo-44263 [https://bugs.python.org/issue?@action=redirect&bpo=44263]: The PyType_Ready() function now raises an error if a type is defined with the Py_TPFLAGS_HAVE_GC flag set but has no traverse function (PyTypeObject.tp_traverse). Patch by Victor Stinner.

bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795]: The undocumented function Py_FrozenMain() is removed from the Limited API.

bpo-44113 [https://bugs.python.org/issue?@action=redirect&bpo=44113]: Deprecate the following functions to configure the Python initialization:

PySys_AddWarnOptionUnicode()

PySys_AddWarnOption()

PySys_AddXOption()

PySys_HasWarnOptions()

Py_SetPath()

Py_SetProgramName()

Py_SetPythonHome()

Py_SetStandardStreamEncoding()

_Py_SetProgramFullPath()

Use the new PyConfig API of the Python Initialization Configuration instead (PEP 587 [https://peps.python.org/pep-0587/]).

bpo-44094 [https://bugs.python.org/issue?@action=redirect&bpo=44094]: Remove PyErr_SetFromErrnoWithUnicodeFilename(), PyErr_SetFromWindowsErrWithUnicodeFilename(), and PyErr_SetExcFromWindowsErrWithUnicodeFilename(). They are not documented and have been deprecated since Python 3.3.

bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795]: PyCodec_Unregister() is now properly exported as a function in the Windows Stable ABI DLL.

bpo-44029 [https://bugs.python.org/issue?@action=redirect&bpo=44029]: Remove deprecated Py_UNICODE APIs: PyUnicode_Encode, PyUnicode_EncodeUTF7, PyUnicode_EncodeUTF8, PyUnicode_EncodeUTF16, PyUnicode_EncodeUTF32, PyUnicode_EncodeLatin1, PyUnicode_EncodeMBCS, PyUnicode_EncodeDecimal, PyUnicode_EncodeRawUnicodeEscape, PyUnicode_EncodeCharmap, PyUnicode_EncodeUnicodeEscape, PyUnicode_TransformDecimalToASCII, PyUnicode_TranslateCharmap, PyUnicodeEncodeError_Create, PyUnicodeTranslateError_Create. See PEP 393 [https://peps.python.org/pep-0393/] and PEP 624 [https://peps.python.org/pep-0624/] for reference.

bpo-42035 [https://bugs.python.org/issue?@action=redirect&bpo=42035]: Add a new PyType_GetName() function to get type’s short name.

Python 3.10.0 beta 1

Release date: 2021-05-03

Security

bpo-43434 [https://bugs.python.org/issue?@action=redirect&bpo=43434]: Creating sqlite3.Connection objects now also produces sqlite3.connect and sqlite3.connect/handle auditing events. Previously these events were only produced by sqlite3.connect() calls. Patch by Erlend E. Aasland.

bpo-43998 [https://bugs.python.org/issue?@action=redirect&bpo=43998]: The ssl module sets more secure cipher suites defaults. Ciphers without forward secrecy and with SHA-1 MAC are disabled by default. Security level 2 prohibits weak RSA, DH, and ECC keys with less than 112 bits of security. SSLContext defaults to minimum protocol version TLS 1.2. Settings are based on Hynek Schlawack’s research.

bpo-43882 [https://bugs.python.org/issue?@action=redirect&bpo=43882]: The presence of newline or tab characters in parts of a URL could allow some forms of attacks.

Following the controlling specification for URLs defined by WHATWG urllib.parse() now removes ASCII newlines and tabs from URLs, preventing such attacks.

bpo-43472 [https://bugs.python.org/issue?@action=redirect&bpo=43472]: Ensures interpreter-level audit hooks receive the cpython.PyInterpreterState_New event when called through the _xxsubinterpreters module.

bpo-43362 [https://bugs.python.org/issue?@action=redirect&bpo=43362]: Fix invalid free in _sha3 module. The issue was introduced in 3.10.0a1. Python 3.9 and earlier are not affected.

bpo-43762 [https://bugs.python.org/issue?@action=redirect&bpo=43762]: Add audit events for sqlite3.connect/handle(), sqlite3.Connection.enable_load_extension(), and sqlite3.Connection.load_extension(). Patch by Erlend E. Aasland.

bpo-43756 [https://bugs.python.org/issue?@action=redirect&bpo=43756]: Add new audit event glob.glob/2 to incorporate the new root_dir and dir_fd arguments added to glob.glob() and glob.iglob().

bpo-36384 [https://bugs.python.org/issue?@action=redirect&bpo=36384]: ipaddress module no longer accepts any leading zeros in IPv4 address strings. Leading zeros are ambiguous and interpreted as octal notation by some libraries. For example the legacy function socket.inet_aton() treats leading zeros as octal notation. glibc implementation of modern inet_pton() does not accept any leading zeros. For a while the ipaddress module used to accept ambiguous leading zeros.

bpo-43075 [https://bugs.python.org/issue?@action=redirect&bpo=43075]: Fix Regular Expression Denial of Service (ReDoS) vulnerability in urllib.request.AbstractBasicAuthHandler. The ReDoS-vulnerable regex has quadratic worst-case complexity and it allows cause a denial of service when identifying crafted invalid RFCs. This ReDoS issue is on the client side and needs remote attackers to control the HTTP server.

bpo-42800 [https://bugs.python.org/issue?@action=redirect&bpo=42800]: Audit hooks are now fired for frame.f_code, traceback.tb_frame, and generator code/frame attribute access.

bpo-37363 [https://bugs.python.org/issue?@action=redirect&bpo=37363]: Add audit events to the http.client module.

Core and Builtins

bpo-43977 [https://bugs.python.org/issue?@action=redirect&bpo=43977]: Prevent classes being both a sequence and a mapping when pattern matching.

bpo-43977 [https://bugs.python.org/issue?@action=redirect&bpo=43977]: Use tp_flags on the class object to determine if the subject is a sequence or mapping when pattern matching. Avoids the need to import collections.abc when pattern matching.

bpo-43892 [https://bugs.python.org/issue?@action=redirect&bpo=43892]: Restore proper validation of complex literal value patterns when parsing match blocks.

bpo-43933 [https://bugs.python.org/issue?@action=redirect&bpo=43933]: Set frame.f_lineno to the line number of the ‘with’ kweyword when executing the call to __exit__.

bpo-43933 [https://bugs.python.org/issue?@action=redirect&bpo=43933]: If the current position in a frame has no line number then set the f_lineno attribute to None, instead of -1, to conform to PEP 626. This should not normally be possible, but might occur in some unusual circumstances.

bpo-43963 [https://bugs.python.org/issue?@action=redirect&bpo=43963]: Importing the _signal module in a subinterpreter has no longer side effects.

bpo-42739 [https://bugs.python.org/issue?@action=redirect&bpo=42739]: The internal representation of line number tables is changed to not use sentinels, and an explicit length parameter is added to the out of process API function PyLineTable_InitAddressRange. This makes the handling of line number tables more robust in some circumstances.

bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908]: Make re types immutable. Patch by Erlend E. Aasland.

bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908]: Make the array.array type immutable. Patch by Erlend E. Aasland.

bpo-43901 [https://bugs.python.org/issue?@action=redirect&bpo=43901]: Change class and module objects to lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object’s __dict__ for backwards compatibility.

bpo-43892 [https://bugs.python.org/issue?@action=redirect&bpo=43892]: Match patterns now use new dedicated AST nodes (MatchValue, MatchSingleton, MatchSequence, MatchStar, MatchMapping, MatchClass) rather than reusing expression AST nodes. MatchAs and MatchOr are now defined as pattern nodes rather than as expression nodes. Patch by Nick Coghlan.

bpo-42725 [https://bugs.python.org/issue?@action=redirect&bpo=42725]: Usage of await/yield/yield from and named expressions within an annotation is now forbidden when PEP 563 is activated.

bpo-43754 [https://bugs.python.org/issue?@action=redirect&bpo=43754]: When performing structural pattern matching (PEP 634 [https://peps.python.org/pep-0634/]), captured names are now left unbound until the entire pattern has matched successfully.

bpo-42737 [https://bugs.python.org/issue?@action=redirect&bpo=42737]: Annotations for complex targets (everything beside simple names) no longer cause any runtime effects with from __future__ import annotations.

bpo-43914 [https://bugs.python.org/issue?@action=redirect&bpo=43914]: SyntaxError exceptions raised by the interpreter will highlight the full error range of the expression that constitutes the syntax error itself, instead of just where the problem is detected. Patch by Pablo Galindo.

bpo-38605 [https://bugs.python.org/issue?@action=redirect&bpo=38605]: Revert making from __future__ import annotations the default. This follows the Steering Council decision to postpone PEP 563 changes to at least Python 3.11. See the original email for more information regarding the decision: https://mail.python.org/archives/list/python-dev@python.org/thread/CLVXXPQ2T2LQ5MP2Y53VVQFCXYWQJHKZ/. Patch by Pablo Galindo.

bpo-43475 [https://bugs.python.org/issue?@action=redirect&bpo=43475]: Hashes of NaN values now depend on object identity. Formerly, they always hashed to 0 even though NaN values are not equal to one another. Having the same hash for unequal values caused pile-ups in hash tables.

bpo-43859 [https://bugs.python.org/issue?@action=redirect&bpo=43859]: Improve the error message for IndentationError exceptions. Patch by Pablo Galindo

bpo-41323 [https://bugs.python.org/issue?@action=redirect&bpo=41323]: Constant tuple folding in bytecode optimizer now reuses tuple in constant table.

bpo-43846 [https://bugs.python.org/issue?@action=redirect&bpo=43846]: Data stack usage is much reduced for large literal and call expressions.

bpo-38530 [https://bugs.python.org/issue?@action=redirect&bpo=38530]: When printing NameError raised by the interpreter, PyErr_Display() will offer suggestions of similar variable names in the function that the exception was raised from. Patch by Pablo Galindo

bpo-43823 [https://bugs.python.org/issue?@action=redirect&bpo=43823]: Improve syntax errors for invalid dictionary literals. Patch by Pablo Galindo.

bpo-43822 [https://bugs.python.org/issue?@action=redirect&bpo=43822]: Improve syntax errors in the parser for missing commas between expressions. Patch by Pablo Galindo.

bpo-43798 [https://bugs.python.org/issue?@action=redirect&bpo=43798]: ast.alias nodes now include source location metadata attributes e.g. lineno, col_offset.

bpo-43797 [https://bugs.python.org/issue?@action=redirect&bpo=43797]: Improve SyntaxError error messages for invalid comparisons. Patch by Pablo Galindo.

bpo-43760 [https://bugs.python.org/issue?@action=redirect&bpo=43760]: Move the flag for checking whether tracing is enabled to the C stack, from the heap. Should speed up dispatch in the interpreter.

bpo-43682 [https://bugs.python.org/issue?@action=redirect&bpo=43682]: Static methods (@staticmethod) and class methods (@classmethod) now inherit the method attributes (__module__, __name__, __qualname__, __doc__, __annotations__) and have a new __wrapped__ attribute. Patch by Victor Stinner.

bpo-43751 [https://bugs.python.org/issue?@action=redirect&bpo=43751]: Fixed a bug where anext(ait, default) would erroneously return None.

bpo-42128 [https://bugs.python.org/issue?@action=redirect&bpo=42128]: __match_args__ is no longer allowed to be a list.

bpo-43683 [https://bugs.python.org/issue?@action=redirect&bpo=43683]: Add GEN_START opcode. Marks start of generator, including async, or coroutine and handles sending values to a newly created generator or coroutine.

bpo-43105 [https://bugs.python.org/issue?@action=redirect&bpo=43105]: Importlib now resolves relative paths when creating module spec objects from file locations.

bpo-43682 [https://bugs.python.org/issue?@action=redirect&bpo=43682]: Static methods (@staticmethod) are now callable as regular functions. Patch by Victor Stinner.

bpo-42609 [https://bugs.python.org/issue?@action=redirect&bpo=42609]: Prevented crashes in the AST validator and optimizer when compiling some absurdly long expressions like "+0"*1000000. RecursionError is now raised instead.

bpo-38530 [https://bugs.python.org/issue?@action=redirect&bpo=38530]: When printing AttributeError, PyErr_Display() will offer suggestions of similar attribute names in the object that the exception was raised from. Patch by Pablo Galindo

Library

bpo-44015 [https://bugs.python.org/issue?@action=redirect&bpo=44015]: In @dataclass(), raise a TypeError if KW_ONLY is specified more than once.

bpo-25478 [https://bugs.python.org/issue?@action=redirect&bpo=25478]: Added a total() method to collections.Counter() to compute the sum of the counts.

bpo-43733 [https://bugs.python.org/issue?@action=redirect&bpo=43733]: Change netrc.netrc to use UTF-8 encoding before using locale encoding.

bpo-43979 [https://bugs.python.org/issue?@action=redirect&bpo=43979]: Removed an unnecessary list comprehension before looping from urllib.parse.parse_qsl(). Patch by Christoph Zwerschke and Donghee Na.

bpo-43993 [https://bugs.python.org/issue?@action=redirect&bpo=43993]: Update bundled pip to 21.1.1.

bpo-43957 [https://bugs.python.org/issue?@action=redirect&bpo=43957]: [Enum] Deprecate TypeError when non-member is used in a containment check; In 3.12 True or False will be returned instead, and containment will return True if the value is either a member of that enum or one of its members’ value.

bpo-42904 [https://bugs.python.org/issue?@action=redirect&bpo=42904]: For backwards compatibility with previous minor versions of Python, if typing.get_type_hints() receives no namespace dictionary arguments, typing.get_type_hints() will search through the global then local namespaces during evaluation of stringized type annotations (string forward references) inside a class.

bpo-43945 [https://bugs.python.org/issue?@action=redirect&bpo=43945]: [Enum] Deprecate non-standard mixin format() behavior: in 3.12 the enum member, not the member’s value, will be used for format() calls.

bpo-41139 [https://bugs.python.org/issue?@action=redirect&bpo=41139]: Deprecate undocumented cgi.log() API.

bpo-43937 [https://bugs.python.org/issue?@action=redirect&bpo=43937]: Fixed the turtle module working with non-default root window.

bpo-43930 [https://bugs.python.org/issue?@action=redirect&bpo=43930]: Update bundled pip to 21.1 and setuptools to 56.0.0

bpo-43907 [https://bugs.python.org/issue?@action=redirect&bpo=43907]: Fix a bug in the pure-Python pickle implementation when using protocol 5, where bytearray instances that occur several time in the pickled object graph would incorrectly unpickle into repeated copies of the bytearray object.

bpo-43926 [https://bugs.python.org/issue?@action=redirect&bpo=43926]: In importlib.metadata, provide a uniform interface to Description, allow for any field to be encoded with multiline values, remove continuation lines from multiline values, and add a .json property for easy access to the PEP 566 JSON-compatible form. Sync with importlib_metadata 4.0.

bpo-43920 [https://bugs.python.org/issue?@action=redirect&bpo=43920]: OpenSSL 3.0.0: load_verify_locations() now returns a consistent error message when cadata contains no valid certificate.

bpo-43607 [https://bugs.python.org/issue?@action=redirect&bpo=43607]: urllib can now convert Windows paths with \\?\ prefixes into URL paths.

bpo-43817 [https://bugs.python.org/issue?@action=redirect&bpo=43817]: Add inspect.get_annotations(), which safely computes the annotations defined on an object. It works around the quirks of accessing the annotations from various types of objects, and makes very few assumptions about the object passed in. inspect.get_annotations() can also correctly un-stringize stringized annotations.

inspect.signature(), inspect.from_callable(), and inspect.from_function() now call inspect.get_annotations() to retrieve annotations. This means inspect.signature() and inspect.from_callable() can now un-stringize stringized annotations, too.

bpo-43284 [https://bugs.python.org/issue?@action=redirect&bpo=43284]: platform.win32_ver derives the windows version from sys.getwindowsversion().platform_version which in turn derives the version from kernel32.dll (which can be of a different version than Windows itself). Therefore change the platform.win32_ver to determine the version using the platform module’s _syscmd_ver private function to return an accurate version.

bpo-42854 [https://bugs.python.org/issue?@action=redirect&bpo=42854]: The ssl module now uses SSL_read_ex and SSL_write_ex internally. The functions support reading and writing of data larger than 2 GB. Writing zero-length data no longer fails with a protocol violation error.

bpo-42333 [https://bugs.python.org/issue?@action=redirect&bpo=42333]: Port _ssl extension module to multiphase initialization.

bpo-43880 [https://bugs.python.org/issue?@action=redirect&bpo=43880]: ssl now raises DeprecationWarning for OP_NO_SSL/TLS* options, old TLS versions, old protocols, and other features that have been deprecated since Python 3.6, 3.7, or OpenSSL 1.1.0.

bpo-41559 [https://bugs.python.org/issue?@action=redirect&bpo=41559]: PEP 612 [https://peps.python.org/pep-0612/] is now implemented purely in Python; builtin types.GenericAlias objects no longer include typing.ParamSpec in __parameters__ (with the exception of collections.abc.Callable‘s GenericAlias). This means previously invalid uses of ParamSpec (such as list[P]) which worked in earlier versions of Python 3.10 alpha, will now raise TypeError during substitution.

bpo-43867 [https://bugs.python.org/issue?@action=redirect&bpo=43867]: The multiprocessing Server class now explicitly catches SystemExit and closes the client connection in this case. It happens when the Server.serve_client() method reaches the end of file (EOF).

bpo-40443 [https://bugs.python.org/issue?@action=redirect&bpo=40443]: Remove unused imports: pyclbr no longer uses copy, and typing no longer uses ast. Patch by Victor Stinner.

bpo-43820 [https://bugs.python.org/issue?@action=redirect&bpo=43820]: Remove an unneeded copy of the namespace passed to dataclasses.make_dataclass().

bpo-43787 [https://bugs.python.org/issue?@action=redirect&bpo=43787]: Add __iter__() method to bz2.BZ2File, gzip.GzipFile, and lzma.LZMAFile. It makes iterating them about 2x faster. Patch by Inada Naoki.

bpo-43680 [https://bugs.python.org/issue?@action=redirect&bpo=43680]: Deprecate io.OpenWrapper and _pyio.OpenWrapper: use io.open and _pyio.open instead. Until Python 3.9, _pyio.open was not a static method and builtins.open was set to OpenWrapper to not become a bound method when set to a class variable. _io.open is a built-in function whereas _pyio.open is a Python function. In Python 3.10, _pyio.open() is now a static method, and builtins.open() is now io.open().

bpo-43680 [https://bugs.python.org/issue?@action=redirect&bpo=43680]: The Python _pyio.open() function becomes a static method to behave as io.open() built-in function: don’t become a bound method when stored as a class variable. It becomes possible since static methods are now callable in Python 3.10. Moreover, _pyio.OpenWrapper() becomes a simple alias to _pyio.open(). Patch by Victor Stinner.

bpo-41515 [https://bugs.python.org/issue?@action=redirect&bpo=41515]: Fix KeyError raised in typing.get_type_hints() due to synthetic modules that don’t appear in sys.modules.

bpo-43776 [https://bugs.python.org/issue?@action=redirect&bpo=43776]: When subprocess.Popen args are provided as a string or as pathlib.Path, the Popen instance repr now shows the right thing.

bpo-42248 [https://bugs.python.org/issue?@action=redirect&bpo=42248]: [Enum] ensure exceptions raised in _missing__ are released

bpo-43744 [https://bugs.python.org/issue?@action=redirect&bpo=43744]: fix issue with enum member name matching the start of a private variable name

bpo-43772 [https://bugs.python.org/issue?@action=redirect&bpo=43772]: Fixed the return value of TypeVar.__ror__. Patch by Jelle Zijlstra.

bpo-43764 [https://bugs.python.org/issue?@action=redirect&bpo=43764]: Add match_args parameter to @dataclass decorator to allow suppression of __match_args__ generation.

bpo-43799 [https://bugs.python.org/issue?@action=redirect&bpo=43799]: OpenSSL 3.0.0: define OPENSSL_API_COMPAT 1.1.1 to suppress deprecation warnings. Python requires OpenSSL 1.1.1 APIs.

bpo-43478 [https://bugs.python.org/issue?@action=redirect&bpo=43478]: Mocks can no longer be used as the specs for other Mocks. As a result, an already-mocked object cannot have an attribute mocked using autospec=True or be the subject of a create_autospec(...) call. This can uncover bugs in tests since these Mock-derived Mocks will always pass certain tests (e.g. isinstance()) and builtin assert functions (e.g. assert_called_once_with) will unconditionally pass.

bpo-43794 [https://bugs.python.org/issue?@action=redirect&bpo=43794]: Add ssl.OP_IGNORE_UNEXPECTED_EOF constants (OpenSSL 3.0.0)

bpo-43785 [https://bugs.python.org/issue?@action=redirect&bpo=43785]: Improve bz2.BZ2File performance by removing the RLock from BZ2File. This makes BZ2File thread unsafe in the face of multiple simultaneous readers or writers, just like its equivalent classes in gzip and lzma have always been. Patch by Inada Naoki.

bpo-43789 [https://bugs.python.org/issue?@action=redirect&bpo=43789]: OpenSSL 3.0.0: Don’t call the password callback function a second time when first call has signaled an error condition.

bpo-43788 [https://bugs.python.org/issue?@action=redirect&bpo=43788]: The header files for ssl error codes are now OpenSSL version-specific. Exceptions will now show correct reason and library codes. The make_ssl_data.py script has been rewritten to use OpenSSL’s text file with error codes.

bpo-43766 [https://bugs.python.org/issue?@action=redirect&bpo=43766]: Implement PEP 647 [https://peps.python.org/pep-0647/] in the typing module by adding TypeGuard.

bpo-25264 [https://bugs.python.org/issue?@action=redirect&bpo=25264]: os.path.realpath() now accepts a strict keyword-only argument. When set to True, OSError is raised if a path doesn’t exist or a symlink loop is encountered.

bpo-43780 [https://bugs.python.org/issue?@action=redirect&bpo=43780]: In importlib.metadata, incorporate changes from importlib_metadata 3.10: Add mtime-based caching during distribution discovery. Flagged use of dict result from entry_points() as deprecated.

The P.args and P.kwargs attributes of typing.ParamSpec are now instances of the new classes typing.ParamSpecArgs and typing.ParamSpecKwargs, which enables a more useful repr(). Patch by Jelle Zijlstra.

bpo-43731 [https://bugs.python.org/issue?@action=redirect&bpo=43731]: Add an encoding parameter logging.fileConfig().

bpo-43712 [https://bugs.python.org/issue?@action=redirect&bpo=43712]: Add encoding and errors parameters to fileinput.input() and fileinput.FileInput.

bpo-38659 [https://bugs.python.org/issue?@action=redirect&bpo=38659]: A simple_enum decorator is added to the enum module to convert a normal class into an Enum. test_simple_enum added to test simple enums against a corresponding normal Enum. Standard library modules updated to use simple_enum.

bpo-43764 [https://bugs.python.org/issue?@action=redirect&bpo=43764]: Fix an issue where __match_args__ generation could fail for some dataclasses.

bpo-43752 [https://bugs.python.org/issue?@action=redirect&bpo=43752]: Fix sqlite3 regression for zero-sized blobs with converters, where b"" was returned instead of None. The regression was introduced by PR 24723. Patch by Erlend E. Aasland.

bpo-43655 [https://bugs.python.org/issue?@action=redirect&bpo=43655]: tkinter dialog windows are now recognized as dialogs by window managers on macOS and X Window.

bpo-43723 [https://bugs.python.org/issue?@action=redirect&bpo=43723]: The following threading methods are now deprecated and should be replaced:

currentThread => threading.current_thread()

activeCount => threading.active_count()

Condition.notifyAll => threading.Condition.notify_all()

Event.isSet => threading.Event.is_set()

Thread.setName => threading.Thread.name

thread.getName => threading.Thread.name

Thread.isDaemon => threading.Thread.daemon

Thread.setDaemon => threading.Thread.daemon

Patch by Jelle Zijlstra.

bpo-2135 [https://bugs.python.org/issue?@action=redirect&bpo=2135]: Deprecate find_module() and find_loader() implementations in importlib and zipimport.

bpo-43534 [https://bugs.python.org/issue?@action=redirect&bpo=43534]: turtle.textinput() and turtle.numinput() create now a transient window working on behalf of the canvas window.

bpo-43532 [https://bugs.python.org/issue?@action=redirect&bpo=43532]: Add the ability to specify keyword-only fields to dataclasses. These fields will become keyword-only arguments to the generated __init__.

bpo-43522 [https://bugs.python.org/issue?@action=redirect&bpo=43522]: Fix problem with hostname_checks_common_name. OpenSSL does not copy hostflags from struct SSL_CTX to struct SSL.

bpo-8978 [https://bugs.python.org/issue?@action=redirect&bpo=8978]: Improve error message for tarfile.open() when lzma / bz2 are unavailable. Patch by Anthony Sottile.

bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967]: Allow bytes separator argument in urllib.parse.parse_qs and urllib.parse.parse_qsl when parsing str query strings. Previously, this raised a TypeError.

bpo-43296 [https://bugs.python.org/issue?@action=redirect&bpo=43296]: Improve sqlite3 error handling: sqlite3_value_blob() errors that set SQLITE_NOMEM now raise MemoryError. Patch by Erlend E. Aasland.

bpo-43312 [https://bugs.python.org/issue?@action=redirect&bpo=43312]: New functions sysconfig.get_preferred_scheme() and sysconfig.get_default_scheme() are added to query a platform for its preferred “user”, “home”, and “prefix” (default) scheme names.

bpo-43265 [https://bugs.python.org/issue?@action=redirect&bpo=43265]: Improve sqlite3.Connection.backup() error handling. The error message for non-existent target database names is now unknown database <database name> instead of SQL logic error. Patch by Erlend E. Aasland.

bpo-41282 [https://bugs.python.org/issue?@action=redirect&bpo=41282]: Install schemes in distutils.command.install are now loaded from sysconfig.

bpo-41282 [https://bugs.python.org/issue?@action=redirect&bpo=41282]: distutils.sysconfig has been merged to sysconfig.

bpo-43176 [https://bugs.python.org/issue?@action=redirect&bpo=43176]: Fixed processing of a dataclass that inherits from a frozen dataclass with no fields. It is now correctly detected as an error.

bpo-43080 [https://bugs.python.org/issue?@action=redirect&bpo=43080]: pprint now has support for dataclasses.dataclass. Patch by Lewis Gaul.

bpo-39950 [https://bugs.python.org/issue?@action=redirect&bpo=39950]: Add pathlib.Path.hardlink_to() method that supersedes link_to(). The new method has the same argument order as symlink_to().

bpo-42904 [https://bugs.python.org/issue?@action=redirect&bpo=42904]: typing.get_type_hints() now checks the local namespace of a class when evaluating PEP 563 [https://peps.python.org/pep-0563/] annotations inside said class.

bpo-42269 [https://bugs.python.org/issue?@action=redirect&bpo=42269]: Add slots parameter to dataclasses.dataclass decorator to automatically generate __slots__ for class. Patch provided by Yurii Karabas.

bpo-39529 [https://bugs.python.org/issue?@action=redirect&bpo=39529]: Deprecated use of asyncio.get_event_loop() without running event loop. Emit deprecation warning for asyncio functions which implicitly create a Future or Task objects if there is no running event loop and no explicit loop argument is passed: ensure_future(), wrap_future(), gather(), shield(), as_completed() and constructors of Future, Task, StreamReader, StreamReaderProtocol.

bpo-18369 [https://bugs.python.org/issue?@action=redirect&bpo=18369]: Certificate and PrivateKey classes were added to the ssl module. Certificates and keys can now be loaded from memory buffer, too.

bpo-41486 [https://bugs.python.org/issue?@action=redirect&bpo=41486]: Use a new output buffer management code for bz2 / lzma / zlib modules, and add .readall() function to _compression.DecompressReader class. These bring some performance improvements. Patch by Ma Lin.

bpo-31870 [https://bugs.python.org/issue?@action=redirect&bpo=31870]: The ssl.get_server_certificate() function now has a timeout parameter.

bpo-41735 [https://bugs.python.org/issue?@action=redirect&bpo=41735]: Fix thread locks in zlib module may go wrong in rare case. Patch by Ma Lin.

bpo-36470 [https://bugs.python.org/issue?@action=redirect&bpo=36470]: Fix dataclasses with InitVars and replace(). Patch by Claudiu Popa.

bpo-40849 [https://bugs.python.org/issue?@action=redirect&bpo=40849]: Expose X509_V_FLAG_PARTIAL_CHAIN ssl flag

bpo-35114 [https://bugs.python.org/issue?@action=redirect&bpo=35114]: ssl.RAND_status() now returns a boolean value (as documented) instead of 1 or 0.

bpo-39906 [https://bugs.python.org/issue?@action=redirect&bpo=39906]: pathlib.Path.stat() and chmod() now accept a follow_symlinks keyword-only argument for consistency with corresponding functions in the os module.

bpo-39899 [https://bugs.python.org/issue?@action=redirect&bpo=39899]: os.path.expanduser() now refuses to guess Windows home directories if the basename of current user’s home directory does not match their username.

pathlib.Path.expanduser() and home() now consistently raise RuntimeError exception when a home directory cannot be resolved. Previously a KeyError exception could be raised on Windows when the "USERNAME" environment variable was unset.

bpo-36076 [https://bugs.python.org/issue?@action=redirect&bpo=36076]: Added SNI support to ssl.get_server_certificate().

bpo-38490 [https://bugs.python.org/issue?@action=redirect&bpo=38490]: Covariance, Pearson’s correlation, and simple linear regression functionality was added to statistics module. Patch by Tymoteusz Wołodźko.

bpo-33731 [https://bugs.python.org/issue?@action=redirect&bpo=33731]: Provide a locale.localize() function, which converts a normalized number string into a locale format.

bpo-32745 [https://bugs.python.org/issue?@action=redirect&bpo=32745]: Fix a regression in the handling of ctypes’ ctypes.c_wchar_p type: embedded null characters would cause a ValueError to be raised. Patch by Zackery Spytz.

Documentation

bpo-43987 [https://bugs.python.org/issue?@action=redirect&bpo=43987]: Add “Annotations Best Practices” document as a new HOWTO.

bpo-43977 [https://bugs.python.org/issue?@action=redirect&bpo=43977]: Document the new Py_TPFLAGS_MAPPING and Py_TPFLAGS_SEQUENCE type flags.

bpo-43959 [https://bugs.python.org/issue?@action=redirect&bpo=43959]: The documentation on the PyContextVar C-API was clarified.

bpo-43938 [https://bugs.python.org/issue?@action=redirect&bpo=43938]: Update dataclasses documentation to express that FrozenInstanceError is derived from AttributeError.

bpo-43778 [https://bugs.python.org/issue?@action=redirect&bpo=43778]: Fix the Sphinx glossary_search extension: create the _static/ sub-directory if it doesn’t exist.

bpo-43755 [https://bugs.python.org/issue?@action=redirect&bpo=43755]: Update documentation to reflect that unparenthesized lambda expressions can no longer be the expression part in an if clause in comprehensions and generator expressions since Python 3.9.

bpo-43739 [https://bugs.python.org/issue?@action=redirect&bpo=43739]: Fixing the example code in Doc/extending/extending.rst to declare and initialize the pmodule variable to be of the right type.

Tests

bpo-43961 [https://bugs.python.org/issue?@action=redirect&bpo=43961]: Fix test_logging.test_namer_rotator_inheritance() on Windows: use os.replace() rather than os.rename(). Patch by Victor Stinner.

bpo-43842 [https://bugs.python.org/issue?@action=redirect&bpo=43842]: Fix a race condition in the SMTP test of test_logging. Don’t close a file descriptor (socket) from a different thread while asyncore.loop() is polling the file descriptor. Patch by Victor Stinner.

bpo-43843 [https://bugs.python.org/issue?@action=redirect&bpo=43843]: test.libregrtest now marks a test as ENV_CHANGED (altered the execution environment) if a thread raises an exception but does not catch it. It sets a hook on threading.excepthook(). Use --fail-env-changed option to mark the test as failed. Patch by Victor Stinner.

bpo-43811 [https://bugs.python.org/issue?@action=redirect&bpo=43811]: Tests multiple OpenSSL versions on GitHub Actions. Use ccache to speed up testing.

bpo-43791 [https://bugs.python.org/issue?@action=redirect&bpo=43791]: OpenSSL 3.0.0: Disable testing of legacy protocols TLS 1.0 and 1.1. Tests are failing with TLSV1_ALERT_INTERNAL_ERROR.

Build

bpo-43567 [https://bugs.python.org/issue?@action=redirect&bpo=43567]: Improved generated code refresh (AST/tokens/opcodes/keywords) on Windows.

bpo-43669 [https://bugs.python.org/issue?@action=redirect&bpo=43669]: Implement PEP 644 [https://peps.python.org/pep-0644/]. Python now requires OpenSSL 1.1.1 or newer.

Windows

bpo-35306 [https://bugs.python.org/issue?@action=redirect&bpo=35306]: Adds additional arguments to os.startfile() function.

bpo-43538 [https://bugs.python.org/issue?@action=redirect&bpo=43538]: Avoid raising errors from pathlib.Path.exists() when passed an invalid filename.

bpo-38822 [https://bugs.python.org/issue?@action=redirect&bpo=38822]: Fixed os.stat() failing on inaccessible directories with a trailing slash, rather than falling back to the parent directory’s metadata. This implicitly affected os.path.exists() and os.path.isdir().

bpo-26227 [https://bugs.python.org/issue?@action=redirect&bpo=26227]: Fixed decoding of host names in socket.gethostbyaddr() and socket.gethostbyname_ex().

bpo-40432 [https://bugs.python.org/issue?@action=redirect&bpo=40432]: Updated pegen regeneration script on Windows to find and use Python 3.8 or higher. Prior to this, pegen regeneration already required 3.8 or higher, but the script may have used lower versions of Python.

bpo-43745 [https://bugs.python.org/issue?@action=redirect&bpo=43745]: Actually updates Windows release to OpenSSL 1.1.1k. Earlier releases were mislabelled and actually included 1.1.1i again.

bpo-43652 [https://bugs.python.org/issue?@action=redirect&bpo=43652]: Update Tcl and Tk to 8.6.11 in Windows installer.

bpo-43492 [https://bugs.python.org/issue?@action=redirect&bpo=43492]: Upgrade Windows installer to use SQLite 3.35.5.

bpo-30555 [https://bugs.python.org/issue?@action=redirect&bpo=30555]: Fix WindowsConsoleIO errors in the presence of fd redirection. Patch by Segev Finer.

macOS

bpo-42119 [https://bugs.python.org/issue?@action=redirect&bpo=42119]: Fix check for macOS SDK paths when building Python. Narrow search to match contents of SDKs, namely only files in /System/Library, /System/IOSSupport, and /usr other than /usr/local. Previously, anything under /System was assumed to be in an SDK which causes problems with the new file system layout in 10.15+ where user file systems may appear to be mounted under /System. Paths in /Library were also incorrectly treated as SDK locations.

bpo-43568 [https://bugs.python.org/issue?@action=redirect&bpo=43568]: Drop support for MACOSX_DEPLOYMENT_TARGET < 10.3

bpo-44009 [https://bugs.python.org/issue?@action=redirect&bpo=44009]: Provide “python3.x-intel64” executable to allow reliably forcing macOS universal2 framework builds to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs. This can be useful for testing or when universal2 wheels are not yet available.

bpo-43851 [https://bugs.python.org/issue?@action=redirect&bpo=43851]: Build SQLite with SQLITE_OMIT_AUTOINIT on macOS. Patch by Erlend E. Aasland.

bpo-43492 [https://bugs.python.org/issue?@action=redirect&bpo=43492]: Update macOS installer to use SQLite 3.35.4.

bpo-42235 [https://bugs.python.org/issue?@action=redirect&bpo=42235]: Mac/BuildScript/build-installer.py will now use “–enable-optimizations” and --with-lto when building on macOS 10.15 or later.

IDLE

bpo-37903 [https://bugs.python.org/issue?@action=redirect&bpo=37903]: Add mouse actions to the shell sidebar. Left click and optional drag selects one or more lines, as with the editor line number sidebar. Right click after selecting raises a context menu with ‘copy with prompts’. This zips together prompts from the sidebar with lines from the selected text.

bpo-43981 [https://bugs.python.org/issue?@action=redirect&bpo=43981]: Fix reference leak in test_sidebar and test_squeezer. Patches by Terry Jan Reedy and Pablo Galindo

bpo-37892 [https://bugs.python.org/issue?@action=redirect&bpo=37892]: Indent IDLE Shell input with spaces instead of tabs

bpo-43655 [https://bugs.python.org/issue?@action=redirect&bpo=43655]: IDLE dialog windows are now recognized as dialogs by window managers on macOS and X Window.

bpo-37903 [https://bugs.python.org/issue?@action=redirect&bpo=37903]: IDLE’s shell now shows prompts in a separate side-bar.

C API

bpo-43916 [https://bugs.python.org/issue?@action=redirect&bpo=43916]: Add a new Py_TPFLAGS_DISALLOW_INSTANTIATION type flag to disallow creating type instances. Patch by Victor Stinner.

bpo-43774 [https://bugs.python.org/issue?@action=redirect&bpo=43774]: Remove the now unused PYMALLOC_DEBUG macro. Debug hooks on memory allocators are now installed by default if Python is built in debug mode (if Py_DEBUG macro is defined). Moreover, they can now be used on Python build in release mode (ex: using PYTHONMALLOC=debug environment variable).

bpo-43962 [https://bugs.python.org/issue?@action=redirect&bpo=43962]: _PyInterpreterState_IDIncref() now calls _PyInterpreterState_IDInitref() and always increments id_refcount. Previously, calling _xxsubinterpreters.get_current() could create an id_refcount inconsistency when a _xxsubinterpreters.InterpreterID object was deallocated. Patch by Victor Stinner.

bpo-28254 [https://bugs.python.org/issue?@action=redirect&bpo=28254]: Add new C-API functions to control the state of the garbage collector: PyGC_Enable(), PyGC_Disable(), PyGC_IsEnabled(), corresponding to the functions in the gc module.

bpo-43908 [https://bugs.python.org/issue?@action=redirect&bpo=43908]: Introduce Py_TPFLAGS_IMMUTABLETYPE flag for immutable type objects, and modify PyType_Ready() to set it for static types. Patch by Erlend E. Aasland.

bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795]: PyMem_Calloc() is now available in the limited C API (Py_LIMITED_API).

bpo-43868 [https://bugs.python.org/issue?@action=redirect&bpo=43868]: PyOS_ReadlineFunctionPointer() is no longer exported by limited C API headers and by python3.dll on Windows. Like any function that takes FILE*, it is not part of the stable ABI.

bpo-43795 [https://bugs.python.org/issue?@action=redirect&bpo=43795]: Stable ABI and limited API definitions are generated from a central manifest (PEP 652 [https://peps.python.org/pep-0652/]).

bpo-43753 [https://bugs.python.org/issue?@action=redirect&bpo=43753]: Add the Py_Is(x, y) function to test if the x object is the y object, the same as x is y in Python. Add also the Py_IsNone(), Py_IsTrue(), Py_IsFalse() functions to test if an object is, respectively, the None singleton, the True singleton or the False singleton. Patch by Victor Stinner.

Python 3.10.0 alpha 7

Release date: 2021-04-05

Security

bpo-42988 [https://bugs.python.org/issue?@action=redirect&bpo=42988]: CVE 2021-3426 [https://www.cve.org/CVERecord?id=CVE-2021-3426]: Remove the getfile feature of the pydoc module which could be abused to read arbitrary files on the disk (directory traversal vulnerability). Moreover, even source code of Python modules can contain sensitive data like passwords. Vulnerability reported by David Schwörer.

bpo-43285 [https://bugs.python.org/issue?@action=redirect&bpo=43285]: ftplib no longer trusts the IP address value returned from the server in response to the PASV command by default. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network.

Code that requires the former vulnerable behavior may set a trust_server_pasv_ipv4_address attribute on their ftplib.FTP instances to True to re-enable it.

bpo-43439 [https://bugs.python.org/issue?@action=redirect&bpo=43439]: Add audit hooks for gc.get_objects(), gc.get_referrers() and gc.get_referents(). Patch by Pablo Galindo.

Core and Builtins

bpo-27129 [https://bugs.python.org/issue?@action=redirect&bpo=27129]: Update CPython bytecode magic number.

bpo-43672 [https://bugs.python.org/issue?@action=redirect&bpo=43672]: Raise ImportWarning when calling find_loader().

bpo-43660 [https://bugs.python.org/issue?@action=redirect&bpo=43660]: Fix crash that happens when replacing sys.stderr with a callable that can remove the object while an exception is being printed. Patch by Pablo Galindo.

bpo-27129 [https://bugs.python.org/issue?@action=redirect&bpo=27129]: The bytecode interpreter uses instruction, rather byte, offsets internally. This reduces the number of EXTENDED_ARG instructions needed and streamlines instruction dispatch a bit.

bpo-40645 [https://bugs.python.org/issue?@action=redirect&bpo=40645]: Fix reference leak in the _hashopenssl extension. Patch by Pablo Galindo.

bpo-42134 [https://bugs.python.org/issue?@action=redirect&bpo=42134]: Calls to find_module() by the import system now raise ImportWarning.

bpo-41064 [https://bugs.python.org/issue?@action=redirect&bpo=41064]: Improve the syntax error for invalid usage of double starred elements (‘**’) in f-strings. Patch by Pablo Galindo.

bpo-43575 [https://bugs.python.org/issue?@action=redirect&bpo=43575]: Speed up calls to map() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-42137 [https://bugs.python.org/issue?@action=redirect&bpo=42137]: The import system now prefers using __spec__ for ModuleType.__repr__ over module_repr().

bpo-43452 [https://bugs.python.org/issue?@action=redirect&bpo=43452]: Added micro-optimizations to _PyType_Lookup() to improve cache lookup performance in the common case of cache hits.

bpo-43555 [https://bugs.python.org/issue?@action=redirect&bpo=43555]: Report the column offset for SyntaxError for invalid line continuation characters. Patch by Pablo Galindo.

bpo-43517 [https://bugs.python.org/issue?@action=redirect&bpo=43517]: Fix misdetection of circular imports when using from pkg.mod import attr, which caused false positives in non-trivial multi-threaded code.

bpo-43497 [https://bugs.python.org/issue?@action=redirect&bpo=43497]: Emit SyntaxWarnings for assertions with tuple constants, this is a regression introduced in python3.7

bpo-39316 [https://bugs.python.org/issue?@action=redirect&bpo=39316]: Tracing now has correct line numbers for attribute accesses when the attribute is on a different line from the object. Improves debugging and profiling for multi-line method chains.

bpo-35883 [https://bugs.python.org/issue?@action=redirect&bpo=35883]: Python no longer fails at startup with a fatal error if a command line argument contains an invalid Unicode character. The Py_DecodeLocale() function now escapes byte sequences which would be decoded as Unicode characters outside the [U+0000; U+10ffff] range.

bpo-43410 [https://bugs.python.org/issue?@action=redirect&bpo=43410]: Fix a bug that was causing the parser to crash when emitting syntax errors when reading input from stdin. Patch by Pablo Galindo

bpo-43406 [https://bugs.python.org/issue?@action=redirect&bpo=43406]: Fix a possible race condition where PyErr_CheckSignals tries to execute a non-Python signal handler.

bpo-42128 [https://bugs.python.org/issue?@action=redirect&bpo=42128]: Add __match_args__ to struct sequence objects. Patch by Pablo Galindo.

bpo-43390 [https://bugs.python.org/issue?@action=redirect&bpo=43390]: CPython now sets the SA_ONSTACK flag in PyOS_setsig for the VM’s default signal handlers. This is friendlier to other in-process code that an extension module or embedding use could pull in (such as Golang’s cgo) where tiny thread stacks are the norm and sigaltstack() has been used to provide for signal handlers. This is a no-op change for the vast majority of processes that don’t use sigaltstack.

bpo-43287 [https://bugs.python.org/issue?@action=redirect&bpo=43287]: Speed up calls to filter() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-37448 [https://bugs.python.org/issue?@action=redirect&bpo=37448]: Add a radix tree based memory map to track in-use obmalloc arenas. Use to replace the old implementation of address_in_range(). The radix tree approach makes it easy to increase pool sizes beyond the OS page size. Boosting the pool and arena size allows obmalloc to handle a significantly higher percentage of requests from its ultra-fast paths.

It also has the advantage of eliminating the memory unsanitary behavior of the previous address_in_range(). The old address_in_range() was marked with the annotations _Py_NO_SANITIZE_ADDRESS, _Py_NO_SANITIZE_THREAD, and _Py_NO_SANITIZE_MEMORY. Those annotations are no longer needed.

To disable the radix tree map, set a preprocessor flag as follows: -DWITH_PYMALLOC_RADIX_TREE=0.

Co-authored-by: Tim Peters <tim.peters@gmail.com>

bpo-29988 [https://bugs.python.org/issue?@action=redirect&bpo=29988]: Only handle asynchronous exceptions and requests to drop the GIL when returning from a call or on the back edges of loops. Makes sure that __exit__() is always called in with statements, even for interrupts.

Library

bpo-43720 [https://bugs.python.org/issue?@action=redirect&bpo=43720]: Document various stdlib deprecations in imp, pkgutil, and importlib.util for removal in Python 3.12.

bpo-43433 [https://bugs.python.org/issue?@action=redirect&bpo=43433]: xmlrpc.client.ServerProxy no longer ignores query and fragment in the URL of the server.

bpo-31956 [https://bugs.python.org/issue?@action=redirect&bpo=31956]: The index() method of array.array now has optional start and stop parameters.

bpo-40066 [https://bugs.python.org/issue?@action=redirect&bpo=40066]: Enum: adjust repr() to show only enum and member name (not value, nor angle brackets) and str() to show only member name. Update and improve documentation to match.

bpo-42136 [https://bugs.python.org/issue?@action=redirect&bpo=42136]: Deprecate all module_repr() methods found in importlib as their use is being phased out by Python 3.12.

bpo-35930 [https://bugs.python.org/issue?@action=redirect&bpo=35930]: Raising an exception raised in a “future” instance will create reference cycles.

bpo-41369 [https://bugs.python.org/issue?@action=redirect&bpo=41369]: Finish updating the vendored libmpdec to version 2.5.1. Patch by Stefan Krah.

bpo-43422 [https://bugs.python.org/issue?@action=redirect&bpo=43422]: Revert the _decimal C API which was added in bpo-41324 [https://bugs.python.org/issue?@action=redirect&bpo=41324].

bpo-43577 [https://bugs.python.org/issue?@action=redirect&bpo=43577]: Fix deadlock when using ssl.SSLContext debug callback with ssl.SSLContext.sni_callback().

bpo-43571 [https://bugs.python.org/issue?@action=redirect&bpo=43571]: It’s now possible to create MPTCP sockets with IPPROTO_MPTCP

bpo-43542 [https://bugs.python.org/issue?@action=redirect&bpo=43542]: image/heic and image/heif were added to mimetypes.

bpo-40645 [https://bugs.python.org/issue?@action=redirect&bpo=40645]: The hmac module now uses OpenSSL’s HMAC implementation when digestmod argument is a hash name or builtin hash function.

bpo-43510 [https://bugs.python.org/issue?@action=redirect&bpo=43510]: Implement PEP 597 [https://peps.python.org/pep-0597/]: Add EncodingWarning warning, -X warn_default_encoding option, PYTHONWARNDEFAULTENCODING environment variable and encoding="locale" argument value.

bpo-43521 [https://bugs.python.org/issue?@action=redirect&bpo=43521]: ast.unparse can now render NaNs and empty sets.

bpo-42914 [https://bugs.python.org/issue?@action=redirect&bpo=42914]: pprint.pprint() gains a new boolean underscore_numbers optional argument to emit integers with thousands separated by an underscore character for improved readability (for example 1_000_000 instead of 1000000).

bpo-41361 [https://bugs.python.org/issue?@action=redirect&bpo=41361]: rotate() calls are now slightly faster due to faster argument parsing.

bpo-43423 [https://bugs.python.org/issue?@action=redirect&bpo=43423]: subprocess.communicate() no longer raises an IndexError when there is an empty stdout or stderr IO buffer during a timeout on Windows.

bpo-27820 [https://bugs.python.org/issue?@action=redirect&bpo=27820]: Fixed long-standing bug of smtplib.SMTP where doing AUTH LOGIN with initial_response_ok=False will fail.

The cause is that SMTP.auth_login _always_ returns a password if provided with a challenge string, thus non-compliant with the standard for AUTH LOGIN.

Also fixes bug with the test for smtpd.

bpo-43445 [https://bugs.python.org/issue?@action=redirect&bpo=43445]: Add frozen modules to sys.stdlib_module_names. For example, add "_frozen_importlib" and "_frozen_importlib_external" names.

bpo-43245 [https://bugs.python.org/issue?@action=redirect&bpo=43245]: Add keyword arguments support to ChainMap.new_child().

bpo-29982 [https://bugs.python.org/issue?@action=redirect&bpo=29982]: Add optional parameter ignore_cleanup_errors to tempfile.TemporaryDirectory() and allow multiple cleanup() attempts. Contributed by C.A.M. Gerlach.

bpo-43428 [https://bugs.python.org/issue?@action=redirect&bpo=43428]: Include changes from importlib_metadata 3.7 [https://importlib-metadata.readthedocs.io/en/latest/history.html#v3-7-0]:

Performance enhancements to distribution discovery.

entry_points only returns unique distributions.

Introduces new EntryPoints object for containing a set of entry points with convenience methods for selecting entry points by group or name. entry_points now returns this object if selection parameters are supplied but continues to return a dict object for compatibility. Users are encouraged to rely on the selection interface. The dict object result is likely to be deprecated in the future.

Added packages_distributions function to return a mapping of packages to the distributions that provide them.

bpo-43332 [https://bugs.python.org/issue?@action=redirect&bpo=43332]: Improves the networking efficiency of http.client when using a proxy via set_tunnel(). Fewer small send calls are made during connection setup.

bpo-43420 [https://bugs.python.org/issue?@action=redirect&bpo=43420]: Improve performance of fractions.Fraction arithmetics for large components. Contributed by Sergey B. Kirpichev.

bpo-43356 [https://bugs.python.org/issue?@action=redirect&bpo=43356]: Allow passing a signal number to _thread.interrupt_main().

bpo-43399 [https://bugs.python.org/issue?@action=redirect&bpo=43399]: Fix ElementTree.extend not working on iterators when using the Python implementation

bpo-43369 [https://bugs.python.org/issue?@action=redirect&bpo=43369]: Improve sqlite3 error handling: If sqlite3_column_text() and sqlite3_column_blob() set SQLITE_NOMEM, MemoryError is now raised. Patch by Erlend E. Aasland.

bpo-43368 [https://bugs.python.org/issue?@action=redirect&bpo=43368]: Fix a regression introduced in PR 24562, where an empty bytestring was fetched as None instead of b'' in sqlite3. Patch by Mariusz Felisiak.

bpo-41282 [https://bugs.python.org/issue?@action=redirect&bpo=41282]: Fixed stacklevel of DeprecationWarning emitted from import distutils.

bpo-42129 [https://bugs.python.org/issue?@action=redirect&bpo=42129]: importlib.resources now honors namespace packages, merging resources from each location in the namespace as introduced in importlib_resources 3.2 and including incidental changes through 5.0.3.

bpo-43295 [https://bugs.python.org/issue?@action=redirect&bpo=43295]: datetime.datetime.strptime() now raises ValueError instead of IndexError when matching 'z' with the %z format specifier.

bpo-43125 [https://bugs.python.org/issue?@action=redirect&bpo=43125]: Return empty string if base64mime.body_encode receive empty bytes

bpo-43084 [https://bugs.python.org/issue?@action=redirect&bpo=43084]: curses.window.enclose() returns now True or False (as was documented) instead of 1 or 0.

bpo-42994 [https://bugs.python.org/issue?@action=redirect&bpo=42994]: Add MIME types for opus, AAC, 3gpp and 3gpp2

bpo-14678 [https://bugs.python.org/issue?@action=redirect&bpo=14678]: Add an invalidate_caches() method to the zipimport.zipimporter class to support importlib.invalidate_caches(). Patch by Desmond Cheong.

bpo-42782 [https://bugs.python.org/issue?@action=redirect&bpo=42782]: Fail fast in shutil.move() to avoid creating destination directories on failure.

bpo-40066 [https://bugs.python.org/issue?@action=redirect&bpo=40066]: Enum’s repr() and str() have changed: repr() is now EnumClass.MemberName and str() is MemberName. Additionally, stdlib Enum’s whose contents are available as module attributes, such as RegexFlag.IGNORECASE, have their repr() as module.name, e.g. re.IGNORECASE.

bpo-26053 [https://bugs.python.org/issue?@action=redirect&bpo=26053]: Fixed bug where the pdb interactive run command echoed the args from the shell command line, even if those have been overridden at the pdb prompt.

bpo-24160 [https://bugs.python.org/issue?@action=redirect&bpo=24160]: Fixed bug where breakpoints did not persist across multiple debugger sessions in pdb’s interactive mode.

bpo-40701 [https://bugs.python.org/issue?@action=redirect&bpo=40701]: When the tempfile.tempdir global variable is set to a value of type bytes, it is now handled consistently. Previously exceptions could be raised from some tempfile APIs when the directory did not already exist in this situation. Also ensures that the tempfile.gettempdir() and tempfile.gettempdirb() functions always return str and bytes respectively.

bpo-39342 [https://bugs.python.org/issue?@action=redirect&bpo=39342]: Expose X509_V_FLAG_ALLOW_PROXY_CERTS as VERIFY_ALLOW_PROXY_CERTS to allow proxy certificate validation as explained in https://docs.openssl.org/1.1.1/man7/proxy-certificates/.

bpo-31861 [https://bugs.python.org/issue?@action=redirect&bpo=31861]: Add builtins.aiter and builtins.anext. Patch by Joshua Bronson (@jab), Daniel Pope (@lordmauve), and Justin Wang (@justin39).

Documentation

bpo-43199 [https://bugs.python.org/issue?@action=redirect&bpo=43199]: Answer “Why is there no goto?” in the Design and History FAQ.

bpo-43407 [https://bugs.python.org/issue?@action=redirect&bpo=43407]: Clarified that a result from time.monotonic(), time.perf_counter(), time.process_time(), or time.thread_time() can be compared with the result from any following call to the same function - not just the next immediate call.

bpo-43354 [https://bugs.python.org/issue?@action=redirect&bpo=43354]: Fix type documentation for Fault.faultCode; the type has to be int instead of str.

bpo-41933 [https://bugs.python.org/issue?@action=redirect&bpo=41933]: Clarified wording of s * n in the Common Sequence Operations

Tests

bpo-37945 [https://bugs.python.org/issue?@action=redirect&bpo=37945]: Fix test_getsetlocale_issue1813() of test_locale: skip the test if setlocale() fails. Patch by Victor Stinner.

bpo-41561 [https://bugs.python.org/issue?@action=redirect&bpo=41561]: Add workaround for Ubuntu’s custom OpenSSL security level policy.

Build

bpo-43179 [https://bugs.python.org/issue?@action=redirect&bpo=43179]: Introduce and correctly use ALIGNOF_X in place of SIZEOF_X for alignment-related code in optimized string routines. Patch by Jessica Clarke.

bpo-43631 [https://bugs.python.org/issue?@action=redirect&bpo=43631]: Update macOS, Windows, and CI to OpenSSL 1.1.1k.

bpo-43617 [https://bugs.python.org/issue?@action=redirect&bpo=43617]: Improve configure.ac: Check for presence of autoconf-archive package and remove our copies of M4 macros.

bpo-43466 [https://bugs.python.org/issue?@action=redirect&bpo=43466]: The configure script now supports --with-openssl-rpath option.

bpo-43372 [https://bugs.python.org/issue?@action=redirect&bpo=43372]: Use _freeze_importlib to generate code for the __hello__ module. This approach ensures the code matches the interpreter version. Previously, PYTHON_FOR_REGEN was used to generate the code, which might be wrong. The marshal format for code objects has changed with bpo-42246 [https://bugs.python.org/issue?@action=redirect&bpo=42246], commit 877df851. Update the code and the expected code sizes in ctypes test_frozentable.

Windows

bpo-43440 [https://bugs.python.org/issue?@action=redirect&bpo=43440]: Build sqlite3 with the R*Tree module enabled. Patch by Erlend E. Aasland.

IDLE

bpo-42225 [https://bugs.python.org/issue?@action=redirect&bpo=42225]: Document that IDLE can fail on Unix either from misconfigured IP masquerade rules or failure displaying complex colored (non-ascii) characters.

C API

bpo-43688 [https://bugs.python.org/issue?@action=redirect&bpo=43688]: The limited C API is now supported if Python is built in debug mode (if the Py_DEBUG macro is defined). In the limited C API, the Py_INCREF() and Py_DECREF() functions are now implemented as opaque function calls, rather than accessing directly the PyObject.ob_refcnt member, if Python is built in debug mode and the Py_LIMITED_API macro targets Python 3.10 or newer. It became possible to support the limited C API in debug mode because the PyObject structure is the same in release and debug mode since Python 3.8 (see bpo-36465 [https://bugs.python.org/issue?@action=redirect&bpo=36465]).

The limited C API is still not supported in the --with-trace-refs special build (Py_TRACE_REFS macro).

Patch by Victor Stinner.

bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244]: Remove the pyarena.h header file with functions:

PyArena_New()

PyArena_Free()

PyArena_Malloc()

PyArena_AddPyObject()

These functions were undocumented, excluded from the limited C API, and were only used internally by the compiler. Patch by Victor Stinner.

bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244]: Remove the compiler and parser functions using struct _mod type, because the public AST C API was removed:

PyAST_Compile()

PyAST_CompileEx()

PyAST_CompileObject()

PyFuture_FromAST()

PyFuture_FromASTObject()

PyParser_ASTFromFile()

PyParser_ASTFromFileObject()

PyParser_ASTFromFilename()

PyParser_ASTFromString()

PyParser_ASTFromStringObject()

These functions were undocumented and excluded from the limited C API. Patch by Victor Stinner.

bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244]: Remove ast.h, asdl.h, and Python-ast.h header files. These functions were undocumented and excluded from the limited C API. Most names defined by these header files were not prefixed by Py and so could create names conflicts. For example, Python-ast.h defined a Yield macro which was conflict with the Yield name used by the Windows <winbase.h> header. Use the Python ast module instead. Patch by Victor Stinner.

bpo-43541 [https://bugs.python.org/issue?@action=redirect&bpo=43541]: Fix a PyEval_EvalCodeEx() regression: fix reference counting on builtins. Patch by Victor Stinner.

bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244]: Remove the symtable.h header file and the undocumented functions:

PyST_GetScope()

PySymtable_Build()

PySymtable_BuildObject()

PySymtable_Free()

Py_SymtableString()

Py_SymtableStringObject()

The Py_SymtableString() function was part the stable ABI by mistake but it could not be used, because the symtable.h header file was excluded from the limited C API.

The Python symtable module remains available and is unchanged.

Patch by Victor Stinner.

bpo-43244 [https://bugs.python.org/issue?@action=redirect&bpo=43244]: Remove the PyAST_Validate() function. It is no longer possible to build a AST object (mod_ty type) with the public C API. The function was already excluded from the limited C API (PEP 384 [https://peps.python.org/pep-0384/]). Patch by Victor Stinner.

Python 3.10.0 alpha 6

Release date: 2021-03-01

Security

bpo-42967 [https://bugs.python.org/issue?@action=redirect&bpo=42967]: Fix web cache poisoning vulnerability by defaulting the query args separator to &, and allowing the user to choose a custom separator.

Core and Builtins

bpo-43321 [https://bugs.python.org/issue?@action=redirect&bpo=43321]: Fix SystemError raised when PyArg_Parse*() is used with # but without PY_SSIZE_T_CLEAN defined.

bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346]: PyArg_Parse*() functions now emits DeprecationWarning when u or Z format is used. See PEP 623 [https://peps.python.org/pep-0623/] for detail.

bpo-43277 [https://bugs.python.org/issue?@action=redirect&bpo=43277]: Add a new PySet_CheckExact() function to the C-API to check if an object is an instance of set but not an instance of a subtype. Patch by Pablo Galindo.

bpo-42990 [https://bugs.python.org/issue?@action=redirect&bpo=42990]: The types.FunctionType constructor now inherits the current builtins if the globals dictionary has no "__builtins__" key, rather than using {"None": None} as builtins: same behavior as eval() and exec() functions. Defining a function with def function(...): ... in Python is not affected, globals cannot be overridden with this syntax: it also inherits the current builtins. Patch by Victor Stinner.

bpo-42990 [https://bugs.python.org/issue?@action=redirect&bpo=42990]: Functions have a new __builtins__ attribute which is used to look for builtin symbols when a function is executed, instead of looking into __globals__['__builtins__']. Patch by Mark Shannon and Victor Stinner.

bpo-43149 [https://bugs.python.org/issue?@action=redirect&bpo=43149]: Improve the error message in the parser for exception groups without parentheses. Patch by Pablo Galindo.

bpo-43121 [https://bugs.python.org/issue?@action=redirect&bpo=43121]: Fixed an incorrect SyntaxError message for missing comma in literals. Patch by Pablo Galindo.

bpo-42819 [https://bugs.python.org/issue?@action=redirect&bpo=42819]: readline: Explicitly disable bracketed paste in the interactive interpreter, even if it’s set in the inputrc, is enabled by default (eg GNU Readline 8.1), or a user calls readline.read_init_file(). The Python REPL has not implemented bracketed paste support. Also, bracketed mode writes the "\x1b[?2004h" escape sequence into stdout which causes test failures in applications that don’t support it. It can still be explicitly enabled by calling readline.parse_and_bind("set enable-bracketed-paste on"). Patch by Dustin Rodrigues.

bpo-42808 [https://bugs.python.org/issue?@action=redirect&bpo=42808]: Simple calls to type(object) are now faster due to the vectorcall calling convention. Patch by Dennis Sweeney.

bpo-42217 [https://bugs.python.org/issue?@action=redirect&bpo=42217]: Make the compiler merges same co_code and co_linetable objects in a module like already did for co_consts.

bpo-41972 [https://bugs.python.org/issue?@action=redirect&bpo=41972]: Substring search functions such as str1 in str2 and str2.find(str1) now sometimes use the “Two-Way” string comparison algorithm to avoid quadratic behavior on long strings.

bpo-42128 [https://bugs.python.org/issue?@action=redirect&bpo=42128]: Implement PEP 634 [https://peps.python.org/pep-0634/] (structural pattern matching). Patch by Brandt Bucher.

bpo-40692 [https://bugs.python.org/issue?@action=redirect&bpo=40692]: In the concurrent.futures.ProcessPoolExecutor, validate that multiprocess.synchronize() is available on a given platform and rely on that check in the concurrent.futures test suite so we can run tests that are unrelated to ProcessPoolExecutor on those platforms.

bpo-38302 [https://bugs.python.org/issue?@action=redirect&bpo=38302]: If object.__ipow__() returns NotImplemented, the operator will correctly fall back to object.__pow__() and object.__rpow__() as expected.

Library

bpo-43316 [https://bugs.python.org/issue?@action=redirect&bpo=43316]: The python -m gzip command line application now properly fails when detecting an unsupported extension. It exits with a non-zero exit code and prints an error message to stderr.

bpo-43317 [https://bugs.python.org/issue?@action=redirect&bpo=43317]: Set the chunk size for the gzip module main function to io.DEFAULT_BUFFER_SIZE. This is slightly faster than the 1024 bytes constant that was used previously.

bpo-43146 [https://bugs.python.org/issue?@action=redirect&bpo=43146]: Handle None in single-arg versions of print_exception() and format_exception().

bpo-43260 [https://bugs.python.org/issue?@action=redirect&bpo=43260]: Fix TextIOWrapper can not flush internal buffer forever after very large text is written.

bpo-43258 [https://bugs.python.org/issue?@action=redirect&bpo=43258]: Prevent needless allocation of sqlite3 aggregate function context when no rows match an aggregate query. Patch by Erlend E. Aasland.

bpo-43251 [https://bugs.python.org/issue?@action=redirect&bpo=43251]: Improve sqlite3 error handling: sqlite3_column_name() failures now result in MemoryError. Patch by Erlend E. Aasland.

bpo-40956 [https://bugs.python.org/issue?@action=redirect&bpo=40956]: Fix segfault in sqlite3.Connection.backup() if no argument was provided. The regression was introduced by PR 23838. Patch by Erlend E. Aasland.

bpo-43172 [https://bugs.python.org/issue?@action=redirect&bpo=43172]: The readline module now passes its tests when built directly against libedit. Existing irreconcilable API differences remain in readline.get_begidx() and readline.get_endidx() behavior based on libreadline vs libedit use.

bpo-43163 [https://bugs.python.org/issue?@action=redirect&bpo=43163]: Fix a bug in codeop that was causing it to not ask for more input when multi-line snippets have unclosed parentheses. Patch by Pablo Galindo

bpo-43162 [https://bugs.python.org/issue?@action=redirect&bpo=43162]: deprecate unsupported ability to access enum members as attributes of other enum members

bpo-43146 [https://bugs.python.org/issue?@action=redirect&bpo=43146]: Fix recent regression in None argument handling in traceback module functions.

bpo-43102 [https://bugs.python.org/issue?@action=redirect&bpo=43102]: The namedtuple __new__ method had its __builtins__ set to None instead of an actual dictionary. This created problems for introspection tools.

bpo-43106 [https://bugs.python.org/issue?@action=redirect&bpo=43106]: Added O_EVTONLY, O_FSYNC, O_SYMLINK and O_NOFOLLOW_ANY for macOS. Patch by Donghee Na.

bpo-42960 [https://bugs.python.org/issue?@action=redirect&bpo=42960]: Adds resource.RLIMIT_KQUEUES constant from FreeBSD to the resource module.

bpo-42151 [https://bugs.python.org/issue?@action=redirect&bpo=42151]: Make the pure Python implementation of xml.etree.ElementTree behave the same as the C implementation (_elementree) regarding default attribute values (by not setting specified_attributes=1).

bpo-29753 [https://bugs.python.org/issue?@action=redirect&bpo=29753]: In ctypes, now packed bitfields are calculated properly and the first item of packed bitfields is now shrank correctly.

Documentation

bpo-27646 [https://bugs.python.org/issue?@action=redirect&bpo=27646]: Clarify that ‘yield from <expr>’ works with any iterable, not just iterators.

bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346]: Update some deprecated unicode APIs which are documented as “will be removed in 4.0” to “3.12”. See PEP 623 [https://peps.python.org/pep-0623/] for detail.

Tests

bpo-43288 [https://bugs.python.org/issue?@action=redirect&bpo=43288]: Fix test_importlib to correctly skip Unicode file tests if the filesystem does not support them.

Build

bpo-43174 [https://bugs.python.org/issue?@action=redirect&bpo=43174]: Windows build now uses /utf-8 compiler option.

bpo-43103 [https://bugs.python.org/issue?@action=redirect&bpo=43103]: Add a new configure --without-static-libpython option to not build the libpythonMAJOR.MINOR.a static library and not install the python.o object file.

bpo-13501 [https://bugs.python.org/issue?@action=redirect&bpo=13501]: The configure script can now use libedit instead of readline with the command line option --with-readline=editline.

bpo-42603 [https://bugs.python.org/issue?@action=redirect&bpo=42603]: Make configure script use pkg-config to detect the location of Tcl/Tk headers and libraries, used to build tkinter.

On macOS, a Tcl/Tk configuration provided by pkg-config will be preferred over Tcl/Tk frameworks installed in /{System/,}Library/Frameworks. If both exist and the latter is preferred, the appropriate --with-tcltk-* configuration options need to be explicitly set.

bpo-39448 [https://bugs.python.org/issue?@action=redirect&bpo=39448]: Add the “regen-frozen” makefile target that regenerates the code for the frozen __hello__ module.

Windows

bpo-43155 [https://bugs.python.org/issue?@action=redirect&bpo=43155]: PyCMethod_New() is now present in python3.lib.

macOS

bpo-41837 [https://bugs.python.org/issue?@action=redirect&bpo=41837]: Update macOS installer build to use OpenSSL 1.1.1j.

IDLE

bpo-43283 [https://bugs.python.org/issue?@action=redirect&bpo=43283]: Document why printing to IDLE’s Shell is often slower than printing to a system terminal and that it can be made faster by pre-formatting a single string before printing.

C API

bpo-43278 [https://bugs.python.org/issue?@action=redirect&bpo=43278]: Always put compiler and system information on the first line of the REPL welcome message.

bpo-43270 [https://bugs.python.org/issue?@action=redirect&bpo=43270]: Remove the private _PyErr_OCCURRED() macro: use the public PyErr_Occurred() function instead.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: Move odictobject.h, parser_interface.h, picklebufobject.h, pydebug.h, and pyfpe.h into the cpython/ directory. They must not be included directly, as they are already included by Python.h: Include Files.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: Move pyarena.h, pyctype.h, and pytime.h into the cpython/ directory. They must not be included directly, as they are already included by Python.h: Include Files.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: PyExceptionClass_Name() is now always declared as a function, in order to hide implementation details. The macro accessed PyTypeObject.tp_name directly. Patch by Erlend E. Aasland.

bpo-43239 [https://bugs.python.org/issue?@action=redirect&bpo=43239]: The PyCFunction_New() function is now exported in the ABI when compiled with -fvisibility=hidden.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: PyIter_Check() is now always declared as a function, in order to hide implementation details. The macro accessed PyTypeObject.tp_iternext directly. Patch by Erlend E. Aasland.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert PyDescr_IsData() macro to a function to hide implementation details: The macro accessed PyTypeObject.tp_descr_set directly. Patch by Erlend E. Aasland.

bpo-43181 [https://bugs.python.org/issue?@action=redirect&bpo=43181]: Convert PyObject_TypeCheck() macro to a static inline function. Patch by Erlend E. Aasland.

Python 3.10.0 alpha 5

Release date: 2021-02-02

Security

bpo-42938 [https://bugs.python.org/issue?@action=redirect&bpo=42938]: Avoid static buffers when computing the repr of ctypes.c_double and ctypes.c_longdouble values.

Core and Builtins

bpo-42990 [https://bugs.python.org/issue?@action=redirect&bpo=42990]: Refactor the PyEval_ family of functions.

An new function _PyEval_Vector is added to simplify calls to Python from C.

_PyEval_EvalCodeWithName is removed

PyEval_EvalCodeEx is retained as part of the API, but is not used internally

bpo-38631 [https://bugs.python.org/issue?@action=redirect&bpo=38631]: Replace Py_FatalError() calls in the compiler with regular SystemError exceptions. Patch by Victor Stinner.

bpo-42997 [https://bugs.python.org/issue?@action=redirect&bpo=42997]: Improve error message for missing “:” before blocks. Patch by Pablo Galindo.

bpo-43017 [https://bugs.python.org/issue?@action=redirect&bpo=43017]: Improve error message in the parser when using un-parenthesised tuples in comprehensions. Patch by Pablo Galindo.

bpo-42986 [https://bugs.python.org/issue?@action=redirect&bpo=42986]: Fix parser crash when reporting syntax errors in f-string with newlines. Patch by Pablo Galindo.

bpo-40176 [https://bugs.python.org/issue?@action=redirect&bpo=40176]: Syntax errors for unterminated string literals now point to the start of the string instead of reporting EOF/EOL.

bpo-42927 [https://bugs.python.org/issue?@action=redirect&bpo=42927]: The inline cache for LOAD_ATTR now also optimizes access to attributes defined by __slots__. This makes reading such attribute up to 30% faster.

bpo-42864 [https://bugs.python.org/issue?@action=redirect&bpo=42864]: Improve error messages in the parser when parentheses are not closed. Patch by Pablo Galindo.

bpo-42924 [https://bugs.python.org/issue?@action=redirect&bpo=42924]: Fix bytearray repetition incorrectly copying data from the start of the buffer, even if the data is offset within the buffer (e.g. after reassigning a slice at the start of the bytearray to a shorter byte string).

bpo-42882 [https://bugs.python.org/issue?@action=redirect&bpo=42882]: Fix the _PyUnicode_FromId() function (_Py_IDENTIFIER(var) API) when Py_Initialize() / Py_Finalize() is called multiple times: preserve _PyRuntime.unicode_ids.next_index value.

bpo-42827 [https://bugs.python.org/issue?@action=redirect&bpo=42827]: Fix a crash when working out the error line of a SyntaxError in some multi-line expressions.

bpo-42823 [https://bugs.python.org/issue?@action=redirect&bpo=42823]: frame.f_lineno is correct even if frame.f_trace is set to True

bpo-37324 [https://bugs.python.org/issue?@action=redirect&bpo=37324]: Remove deprecated aliases to Collections 추상 베이스 클래스 from the collections module.

bpo-41994 [https://bugs.python.org/issue?@action=redirect&bpo=41994]: Fixed possible leak in import when sys.modules is not a dict.

bpo-27772 [https://bugs.python.org/issue?@action=redirect&bpo=27772]: In string formatting, preceding the width field by '0' no longer affects the default alignment for strings.

Library

bpo-43108 [https://bugs.python.org/issue?@action=redirect&bpo=43108]: Fixed a reference leak in the curses module. Patch by Pablo Galindo

bpo-43077 [https://bugs.python.org/issue?@action=redirect&bpo=43077]: Update the bundled pip to 21.0.1 and setuptools to 52.0.0.

bpo-41282 [https://bugs.python.org/issue?@action=redirect&bpo=41282]: Deprecate distutils in documentation and add warning on import.

bpo-43014 [https://bugs.python.org/issue?@action=redirect&bpo=43014]: Improve performance of tokenize by 20-30%. Patch by Anthony Sottile.

bpo-42323 [https://bugs.python.org/issue?@action=redirect&bpo=42323]: Fix math.nextafter() for NaN on AIX.

bpo-42955 [https://bugs.python.org/issue?@action=redirect&bpo=42955]: Add sys.stdlib_module_names, containing the list of the standard library module names. Patch by Victor Stinner.

bpo-42944 [https://bugs.python.org/issue?@action=redirect&bpo=42944]: Fix random.Random.sample when counts argument is not None.

bpo-42934 [https://bugs.python.org/issue?@action=redirect&bpo=42934]: Use TracebackException’s new compact param in TestResult to reduce time and memory consumed by traceback formatting.

bpo-42931 [https://bugs.python.org/issue?@action=redirect&bpo=42931]: Add randbytes() to random.__all__.

bpo-38250 [https://bugs.python.org/issue?@action=redirect&bpo=38250]: [Enum] Flags consisting of a single bit are now considered canonical, and will be the only flags returned from listing and iterating over a Flag class or a Flag member. Multi-bit flags are considered aliases; they will be returned from lookups and operations that result in their value. Iteration for both Flag and Flag members is in definition order.

bpo-42877 [https://bugs.python.org/issue?@action=redirect&bpo=42877]: Added the compact parameter to the constructor of traceback.TracebackException to reduce time and memory for use cases that only need to call TracebackException.format() and TracebackException.format_exception_only().

bpo-42923 [https://bugs.python.org/issue?@action=redirect&bpo=42923]: The Py_FatalError() function and the faulthandler module now dump the list of extension modules on a fatal error.

bpo-42848 [https://bugs.python.org/issue?@action=redirect&bpo=42848]: Removed recursion from TracebackException to allow it to handle long exception chains.

bpo-42901 [https://bugs.python.org/issue?@action=redirect&bpo=42901]: [Enum] move member creation from EnumMeta.__new__ to _proto_member.__set_name__, allowing members to be created and visible in __init_subclass__.

bpo-42780 [https://bugs.python.org/issue?@action=redirect&bpo=42780]: Fix os.set_inheritable() for O_PATH file descriptors on Linux.

bpo-42866 [https://bugs.python.org/issue?@action=redirect&bpo=42866]: Fix a reference leak in the getcodec() function of CJK codecs. Patch by Victor Stinner.

bpo-42846 [https://bugs.python.org/issue?@action=redirect&bpo=42846]: Convert the 6 CJK codec extension modules (_codecs_cn, _codecs_hk, _codecs_iso2022, _codecs_jp, _codecs_kr and _codecs_tw) to the multiphase initialization API (PEP 489 [https://peps.python.org/pep-0489/]). Patch by Victor Stinner.

bpo-42851 [https://bugs.python.org/issue?@action=redirect&bpo=42851]: remove __init_subclass__ support for Enum members

bpo-42834 [https://bugs.python.org/issue?@action=redirect&bpo=42834]: Make internal caches of the _json module compatible with subinterpreters.

bpo-41748 [https://bugs.python.org/issue?@action=redirect&bpo=41748]: Fix HTMLParser parsing rules for element attributes containing commas with spaces. Patch by Karl Dubost.

bpo-40810 [https://bugs.python.org/issue?@action=redirect&bpo=40810]: Require SQLite 3.7.15 or newer. Patch by Erlend E. Aasland.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Convert the _multibytecodec extension module (CJK codecs) to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]). Patch by Erlend E. Aasland.

bpo-42802 [https://bugs.python.org/issue?@action=redirect&bpo=42802]: The distutils bdist_wininst command deprecated in Python 3.8 has been removed. The distutils bdist_wheel command is now recommended to distribute binary packages on Windows.

bpo-24464 [https://bugs.python.org/issue?@action=redirect&bpo=24464]: The undocumented built-in function sqlite3.enable_shared_cache is now deprecated, scheduled for removal in Python 3.12. Its use is strongly discouraged by the SQLite3 documentation. Patch by Erlend E. Aasland.

bpo-42384 [https://bugs.python.org/issue?@action=redirect&bpo=42384]: Make pdb populate sys.path[0] exactly the same as regular python execution.

bpo-42383 [https://bugs.python.org/issue?@action=redirect&bpo=42383]: Fix pdb: previously pdb would fail to restart the debugging target if it was specified using a relative path and the current directory changed.

bpo-42005 [https://bugs.python.org/issue?@action=redirect&bpo=42005]: Fix CLI of cProfile and profile to catch BrokenPipeError.

bpo-41604 [https://bugs.python.org/issue?@action=redirect&bpo=41604]: Don’t decrement the reference count of the previous user_ptr when set_panel_userptr fails.

bpo-41149 [https://bugs.python.org/issue?@action=redirect&bpo=41149]: Allow executing callables that have a boolean value of False when passed to Threading.thread as the target. Patch contributed by Barney Stratford.

bpo-38307 [https://bugs.python.org/issue?@action=redirect&bpo=38307]: Add an ‘end_lineno’ attribute to the Class and Function objects that appear in the tree returned by pyclbr functions. This and the existing ‘lineno’ attribute define the extent of class and def statements. Patch by Aviral Srivastava.

bpo-39273 [https://bugs.python.org/issue?@action=redirect&bpo=39273]: The BUTTON5_* constants are now exposed in the curses module if available.

bpo-33289 [https://bugs.python.org/issue?@action=redirect&bpo=33289]: Correct call to tkinter.colorchooser to return RGB triplet of ints instead of floats. Patch by Cheryl Sabella.

Documentation

bpo-40304 [https://bugs.python.org/issue?@action=redirect&bpo=40304]: Fix doc for type(name, bases, dict). Patch by Boris Verkhovskiy and Éric Araujo.

bpo-42811 [https://bugs.python.org/issue?@action=redirect&bpo=42811]: Updated importlib.util.resolve_name() doc to use __spec__.parent instead of __package__. (Thanks Yair Frid.)

Tests

bpo-40823 [https://bugs.python.org/issue?@action=redirect&bpo=40823]: Use unittest.TestLoader().loadTestsFromTestCase() instead of unittest.makeSuite() in sqlite3 tests. Patch by Erlend E. Aasland.

bpo-40810 [https://bugs.python.org/issue?@action=redirect&bpo=40810]: In sqlite3, fix CheckTraceCallbackContent for SQLite pre 3.7.15.

Build

bpo-43031 [https://bugs.python.org/issue?@action=redirect&bpo=43031]: Pass --timeout=$(TESTTIMEOUT) option to the default profile task ./python -m test --pgo command.

bpo-36143 [https://bugs.python.org/issue?@action=redirect&bpo=36143]: make regen-all now also runs regen-keyword. Patch by Victor Stinner.

bpo-42874 [https://bugs.python.org/issue?@action=redirect&bpo=42874]: Removed the grep -q and -E flags in the tzpath validation section of the configure script to better accommodate users of some platforms (specifically Solaris 10).

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Add library search path by wr-cc in add_cross_compiling_paths() for VxWorks.

bpo-42856 [https://bugs.python.org/issue?@action=redirect&bpo=42856]: Add --with-wheel-pkg-dir=PATH option to the ./configure script. If specified, the ensurepip module looks for setuptools and pip wheel packages in this directory: if both are present, these wheel packages are used instead of ensurepip bundled wheel packages.

Some Linux distribution packaging policies recommend against bundling dependencies. For example, Fedora installs wheel packages in the /usr/share/python-wheels/ directory and don’t install the ensurepip._bundled package.

Windows

bpo-41837 [https://bugs.python.org/issue?@action=redirect&bpo=41837]: Updated Windows installer to include OpenSSL 1.1.1i

bpo-42584 [https://bugs.python.org/issue?@action=redirect&bpo=42584]: Upgrade Windows installer to use SQLite 3.34.0.

macOS

bpo-42504 [https://bugs.python.org/issue?@action=redirect&bpo=42504]: Ensure that the value of sysconfig.get_config_var(‘MACOSX_DEPLOYMENT_TARGET’) is always a string, even in when the value is parsable as an integer.

IDLE

bpo-43008 [https://bugs.python.org/issue?@action=redirect&bpo=43008]: Make IDLE invoke sys.excepthook() in normal, 2-process mode. Patch by Ken Hilton.

bpo-33065 [https://bugs.python.org/issue?@action=redirect&bpo=33065]: Fix problem debugging user classes with __repr__ method.

bpo-23544 [https://bugs.python.org/issue?@action=redirect&bpo=23544]: Disable Debug=>Stack Viewer when user code is running or Debugger is active, to prevent hang or crash. Patch by Zackery Spytz.

bpo-32631 [https://bugs.python.org/issue?@action=redirect&bpo=32631]: Finish zzdummy example extension module: make menu entries work; add docstrings and tests with 100% coverage.

C API

bpo-42979 [https://bugs.python.org/issue?@action=redirect&bpo=42979]: When Python is built in debug mode (with C assertions), calling a type slot like sq_length (__len__() in Python) now fails with a fatal error if the slot succeeded with an exception set, or failed with no exception set. The error message contains the slot, the type name, and the current exception (if an exception is set). Patch by Victor Stinner.

bpo-43030 [https://bugs.python.org/issue?@action=redirect&bpo=43030]: Fixed a compiler warning in Py_UNICODE_ISSPACE() on platforms with signed wchar_t.

Python 3.10.0 alpha 4

Release date: 2021-01-04

Core and Builtins

bpo-42814 [https://bugs.python.org/issue?@action=redirect&bpo=42814]: Fix undefined behavior in Objects/genericaliasobject.c.

bpo-42806 [https://bugs.python.org/issue?@action=redirect&bpo=42806]: Fix the column offsets for f-strings ast nodes surrounded by parentheses and for nodes that spawn multiple lines. Patch by Pablo Galindo.

bpo-40631 [https://bugs.python.org/issue?@action=redirect&bpo=40631]: Fix regression where a single parenthesized starred expression was a valid assignment target.

bpo-27794 [https://bugs.python.org/issue?@action=redirect&bpo=27794]: Improve the error message for failed writes/deletes to property objects. When possible, the attribute name is now shown. Patch provided by Yurii Karabas.

bpo-42745 [https://bugs.python.org/issue?@action=redirect&bpo=42745]: Make the type attribute lookup cache per-interpreter. Patch by Victor Stinner.

bpo-42246 [https://bugs.python.org/issue?@action=redirect&bpo=42246]: Jumps to jumps are not eliminated when it would break PEP 626.

bpo-42246 [https://bugs.python.org/issue?@action=redirect&bpo=42246]: Make sure that the f_lasti and f_lineno attributes of a frame are set correctly when an exception is raised or re-raised. Required for PEP 626.

bpo-32381 [https://bugs.python.org/issue?@action=redirect&bpo=32381]: The coding cookie (ex: # coding: latin1) is now ignored in the command passed to the -c command line option. Patch by Victor Stinner.

bpo-30858 [https://bugs.python.org/issue?@action=redirect&bpo=30858]: Improve error location in expressions that contain assignments. Patch by Pablo Galindo and Lysandros Nikolaou.

bpo-42615 [https://bugs.python.org/issue?@action=redirect&bpo=42615]: Remove jump commands made redundant by the deletion of unreachable bytecode blocks

bpo-42639 [https://bugs.python.org/issue?@action=redirect&bpo=42639]: Make the atexit module state per-interpreter. It is now safe have more than one atexit module instance. Patch by Donghee Na and Victor Stinner.

bpo-32381 [https://bugs.python.org/issue?@action=redirect&bpo=32381]: Fix encoding name when running a .pyc file on Windows: PyRun_SimpleFileExFlags() now uses the correct encoding to decode the filename.

bpo-42195 [https://bugs.python.org/issue?@action=redirect&bpo=42195]: The __args__ of the parameterized generics for typing.Callable and collections.abc.Callable are now consistent. The __args__ for collections.abc.Callable are now flattened while typing.Callable’s have not changed. To allow this change, types.GenericAlias can now be subclassed and collections.abc.Callable’s __class_getitem__ will now return a subclass of types.GenericAlias. Tests for typing were also updated to not subclass things like Callable[..., T] as that is not a valid base class. Finally, both Callables no longer validate their argtypes, in Callable[[argtypes], resulttype] to prepare for PEP 612 [https://peps.python.org/pep-0612/]. Patch by Ken Jin.

bpo-40137 [https://bugs.python.org/issue?@action=redirect&bpo=40137]: Convert functools module to use PyType_FromModuleAndSpec().

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert array to use heap types, and establish module state for these.

bpo-42008 [https://bugs.python.org/issue?@action=redirect&bpo=42008]: Fix _random.Random() seeding.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the pyexpat extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40521 [https://bugs.python.org/issue?@action=redirect&bpo=40521]: Make the Unicode dictionary of interned strings compatible with subinterpreters. Patch by Victor Stinner.

bpo-39465 [https://bugs.python.org/issue?@action=redirect&bpo=39465]: Make _PyUnicode_FromId() function compatible with subinterpreters. Each interpreter now has an array of identifier objects (interned strings decoded from UTF-8). Patch by Victor Stinner.

Library

bpo-42257 [https://bugs.python.org/issue?@action=redirect&bpo=42257]: Handle empty string in variable executable in platform.libc_ver()

bpo-42772 [https://bugs.python.org/issue?@action=redirect&bpo=42772]: randrange() now raises a TypeError when step is specified without a stop argument. Formerly, it silently ignored the step argument.

bpo-42759 [https://bugs.python.org/issue?@action=redirect&bpo=42759]: Fixed equality comparison of tkinter.Variable and tkinter.font.Font. Objects which belong to different Tcl interpreters are now always different, even if they have the same name.

bpo-42756 [https://bugs.python.org/issue?@action=redirect&bpo=42756]: Configure LMTP Unix-domain socket to use socket global default timeout when a timeout is not explicitly provided.

bpo-23328 [https://bugs.python.org/issue?@action=redirect&bpo=23328]: Allow / character in username, password fields on _PROXY envars.

bpo-42740 [https://bugs.python.org/issue?@action=redirect&bpo=42740]: typing.get_args() and typing.get_origin() now support PEP 604 [https://peps.python.org/pep-0604/] union types and PEP 612 [https://peps.python.org/pep-0612/] additions to Callable.

bpo-42655 [https://bugs.python.org/issue?@action=redirect&bpo=42655]: subprocess extra_groups is now correctly passed into setgroups() system call.

bpo-42727 [https://bugs.python.org/issue?@action=redirect&bpo=42727]: EnumMeta.__prepare__ now accepts **kwds to properly support __init_subclass__

bpo-38308 [https://bugs.python.org/issue?@action=redirect&bpo=38308]: Add optional weights to statistics.harmonic_mean().

bpo-42721 [https://bugs.python.org/issue?@action=redirect&bpo=42721]: When simple query dialogs (tkinter.simpledialog), message boxes (tkinter.messagebox) or color choose dialog (tkinter.colorchooser) are created without arguments master and parent, and the default root window is not yet created, and NoDefaultRoot() was not called, a new temporal hidden root window will be created automatically. It will not be set as the default root window and will be destroyed right after closing the dialog window. It will help to use these simple dialog windows in programs which do not need other GUI.

bpo-25246 [https://bugs.python.org/issue?@action=redirect&bpo=25246]: Optimized collections.deque.remove().

bpo-35728 [https://bugs.python.org/issue?@action=redirect&bpo=35728]: Added a root parameter to tkinter.font.nametofont().

bpo-15303 [https://bugs.python.org/issue?@action=redirect&bpo=15303]: tkinter supports now widgets with boolean value False.

bpo-42681 [https://bugs.python.org/issue?@action=redirect&bpo=42681]: Fixed range checks for color and pair numbers in curses.

bpo-42685 [https://bugs.python.org/issue?@action=redirect&bpo=42685]: Improved placing of simple query windows in Tkinter (such as tkinter.simpledialog.askinteger()). They are now centered at the center of the parent window if it is specified and shown, otherwise at the center of the screen.

bpo-9694 [https://bugs.python.org/issue?@action=redirect&bpo=9694]: Argparse help no longer uses the confusing phrase, “optional arguments”. It uses “options” instead.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _thread extension module to the multiphase initialization API (PEP 489 [https://peps.python.org/pep-0489/]) and convert its static types to heap types.

bpo-37961 [https://bugs.python.org/issue?@action=redirect&bpo=37961]: Fix crash in tracemalloc.Traceback.__repr__() (regressed in Python 3.9).

bpo-42630 [https://bugs.python.org/issue?@action=redirect&bpo=42630]: tkinter functions and constructors which need a default root window raise now RuntimeError with descriptive message instead of obscure AttributeError or NameError if it is not created yet or cannot be created automatically.

bpo-42639 [https://bugs.python.org/issue?@action=redirect&bpo=42639]: atexit._run_exitfuncs() now logs callback exceptions using sys.unraisablehook, rather than logging them directly into sys.stderr and raise the last exception.

bpo-42644 [https://bugs.python.org/issue?@action=redirect&bpo=42644]: logging.disable will now validate the types and value of its parameter. It also now accepts strings representing the levels (as does logging.setLevel) instead of only the numerical values.

bpo-42639 [https://bugs.python.org/issue?@action=redirect&bpo=42639]: At Python exit, if a callback registered with atexit.register() fails, its exception is now logged. Previously, only some exceptions were logged, and the last exception was always silently ignored.

bpo-36541 [https://bugs.python.org/issue?@action=redirect&bpo=36541]: Fixed lib2to3.pgen2 to be able to parse PEP-570 positional only argument syntax.

bpo-42382 [https://bugs.python.org/issue?@action=redirect&bpo=42382]: In importlib.metadata: - EntryPoint objects now expose a .dist object referencing the Distribution when constructed from a Distribution. - Add support for package discovery under package normalization rules. - The object returned by metadata() now has a formally defined protocol called PackageMetadata with declared support for the .get_all() method. - Synced with importlib_metadata 3.3.

bpo-41877 [https://bugs.python.org/issue?@action=redirect&bpo=41877]: A check is added against misspellings of autospect, auto_spec and set_spec being passed as arguments to patch, patch.object and create_autospec.

bpo-39717 [https://bugs.python.org/issue?@action=redirect&bpo=39717]: [tarfile] update nested exception raising to use from None or from e

bpo-41877 [https://bugs.python.org/issue?@action=redirect&bpo=41877]: AttributeError for suspected misspellings of assertions on mocks are now pointing out that the cause are misspelled assertions and also what to do if the misspelling is actually an intended attribute name. The unittest.mock document is also updated to reflect the current set of recognised misspellings.

bpo-41559 [https://bugs.python.org/issue?@action=redirect&bpo=41559]: Implemented PEP 612 [https://peps.python.org/pep-0612/]: added ParamSpec and Concatenate to typing. Patch by Ken Jin.

bpo-42385 [https://bugs.python.org/issue?@action=redirect&bpo=42385]: StrEnum: fix _generate_next_value_ to return a str

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Define THREAD_STACK_SIZE for VxWorks.

bpo-34750 [https://bugs.python.org/issue?@action=redirect&bpo=34750]: [Enum] _EnumDict.update() is now supported.

bpo-42517 [https://bugs.python.org/issue?@action=redirect&bpo=42517]: Enum: private names do not become members / do not generate errors – they remain normal attributes

bpo-42678 [https://bugs.python.org/issue?@action=redirect&bpo=42678]: Enum: call __init_subclass__ after members have been added

bpo-28964 [https://bugs.python.org/issue?@action=redirect&bpo=28964]: ast.literal_eval() adds line number information (if available) in error message for malformed nodes.

bpo-42470 [https://bugs.python.org/issue?@action=redirect&bpo=42470]: random.sample() no longer warns on a sequence which is also a set.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: posixpath.expanduser() returns the input path unchanged if user home directory is None on VxWorks.

bpo-42388 [https://bugs.python.org/issue?@action=redirect&bpo=42388]: Fix subprocess.check_output(…, input=None) behavior when text=True to be consistent with that of the documentation and universal_newlines=True.

bpo-34463 [https://bugs.python.org/issue?@action=redirect&bpo=34463]: Fixed discrepancy between traceback and the interpreter in formatting of SyntaxError with lineno not set (traceback was changed to match interpreter).

bpo-42393 [https://bugs.python.org/issue?@action=redirect&bpo=42393]: Raise OverflowError instead of silent truncation in socket.ntohs() and socket.htons(). Silent truncation was deprecated in Python 3.7. Patch by Erlend E. Aasland

bpo-42222 [https://bugs.python.org/issue?@action=redirect&bpo=42222]: Harmonized random.randrange() argument handling to match range().

The integer test and conversion in randrange() now uses operator.index().

Non-integer arguments to randrange() are deprecated.

The ValueError is deprecated in favor of a TypeError.

It now runs a little faster than before.

(Contributed by Raymond Hettinger and Serhiy Storchaka.)

bpo-42163 [https://bugs.python.org/issue?@action=redirect&bpo=42163]: Restore compatibility for uname_result around deepcopy and _replace.

bpo-42090 [https://bugs.python.org/issue?@action=redirect&bpo=42090]: zipfile.Path.joinpath now accepts arbitrary arguments, same as pathlib.Path.joinpath.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _csv module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-42059 [https://bugs.python.org/issue?@action=redirect&bpo=42059]: typing.TypedDict types created using the alternative call-style syntax now correctly respect the total keyword argument when setting their __required_keys__ and __optional_keys__ class attributes.

bpo-41960 [https://bugs.python.org/issue?@action=redirect&bpo=41960]: Add globalns and localns parameters to the inspect.signature() and inspect.Signature.from_callable().

bpo-41907 [https://bugs.python.org/issue?@action=redirect&bpo=41907]: fix format() behavior for IntFlag

bpo-41891 [https://bugs.python.org/issue?@action=redirect&bpo=41891]: Ensure asyncio.wait_for waits for task completion

bpo-24792 [https://bugs.python.org/issue?@action=redirect&bpo=24792]: Fixed bug where zipimporter sometimes reports an incorrect cause of import errors.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix site and sysconfig modules for VxWorks RTOS which has no home directories.

bpo-41462 [https://bugs.python.org/issue?@action=redirect&bpo=41462]: Add os.set_blocking() support for VxWorks RTOS.

bpo-40219 [https://bugs.python.org/issue?@action=redirect&bpo=40219]: Lowered tkinter.ttk.LabeledScale dummy widget to prevent hiding part of the content label.

bpo-37193 [https://bugs.python.org/issue?@action=redirect&bpo=37193]: Fixed memory leak in socketserver.ThreadingMixIn introduced in Python 3.7.

bpo-39068 [https://bugs.python.org/issue?@action=redirect&bpo=39068]: Fix initialization race condition in a85encode() and b85encode() in base64. Patch by Brandon Stansbury.

Documentation

bpo-17140 [https://bugs.python.org/issue?@action=redirect&bpo=17140]: Add documentation for the multiprocessing.pool.ThreadPool class.

bpo-34398 [https://bugs.python.org/issue?@action=redirect&bpo=34398]: Prominently feature listings from the glossary in documentation search results. Patch by Ammar Askar.

Tests

bpo-42794 [https://bugs.python.org/issue?@action=redirect&bpo=42794]: Update test_nntplib to use official group name of news.aioe.org for testing. Patch by Donghee Na.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Skip some asyncio tests on VxWorks.

bpo-42641 [https://bugs.python.org/issue?@action=redirect&bpo=42641]: Enhance test_select.test_select(): it now takes 500 milliseconds rather than 10 seconds. Use Python rather than a shell to make the test more portable.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Skip some tests in _test_all_chown_common() on VxWorks.

bpo-42199 [https://bugs.python.org/issue?@action=redirect&bpo=42199]: Fix bytecode helper assertNotInBytecode.

bpo-41443 [https://bugs.python.org/issue?@action=redirect&bpo=41443]: Add more attribute checking in test_posix.py

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Disable os.popen and impacted tests on VxWorks

bpo-41439 [https://bugs.python.org/issue?@action=redirect&bpo=41439]: Port test_ssl and test_uuid to VxWorks RTOS.

Build

bpo-42692 [https://bugs.python.org/issue?@action=redirect&bpo=42692]: Fix __builtin_available check on older compilers. Patch by Joshua Root.

bpo-27640 [https://bugs.python.org/issue?@action=redirect&bpo=27640]: Added --disable-test-modules option to the configure script: don’t build nor install test modules. Patch by Xavier de Gaye, Thomas Petazzoni and Peixing Xin.

bpo-42604 [https://bugs.python.org/issue?@action=redirect&bpo=42604]: Now all platforms use a value for the “EXT_SUFFIX” build variable derived from SOABI (for instance in freeBSD, “EXT_SUFFIX” is now “.cpython-310d.so” instead of “.so”). Previously only Linux, Mac and VxWorks were using a value for “EXT_SUFFIX” that included “SOABI”.

bpo-42598 [https://bugs.python.org/issue?@action=redirect&bpo=42598]: Fix implicit function declarations in configure which could have resulted in incorrect configuration checks. Patch contributed by Joshua Root.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Enable libpython3.so for VxWorks.

bpo-29076 [https://bugs.python.org/issue?@action=redirect&bpo=29076]: Add fish shell support to macOS installer.

macOS

bpo-42361 [https://bugs.python.org/issue?@action=redirect&bpo=42361]: Update macOS installer build to use Tcl/Tk 8.6.11 (rc2, expected to be final release).

bpo-41837 [https://bugs.python.org/issue?@action=redirect&bpo=41837]: Update macOS installer build to use OpenSSL 1.1.1i.

bpo-42584 [https://bugs.python.org/issue?@action=redirect&bpo=42584]: Update macOS installer to use SQLite 3.34.0.

Tools/Demos

bpo-42726 [https://bugs.python.org/issue?@action=redirect&bpo=42726]: Fixed Python 3 compatibility issue with gdb/libpython.py handling of attribute dictionaries.

bpo-42613 [https://bugs.python.org/issue?@action=redirect&bpo=42613]: Fix freeze.py tool to use the prope config and library directories. Patch by Victor Stinner.

C API

bpo-42591 [https://bugs.python.org/issue?@action=redirect&bpo=42591]: Export the Py_FrozenMain() function: fix a Python 3.9.0 regression. Python 3.9 uses -fvisibility=hidden and the function was not exported explicitly and so not exported.

bpo-32381 [https://bugs.python.org/issue?@action=redirect&bpo=32381]: Remove the private _Py_fopen() function which is no longer needed. Use _Py_wfopen() or _Py_fopen_obj() instead. Patch by Victor Stinner.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port resource extension module to module state

bpo-42111 [https://bugs.python.org/issue?@action=redirect&bpo=42111]: Update the xxlimited module to be a better example of how to use the limited C API.

bpo-40052 [https://bugs.python.org/issue?@action=redirect&bpo=40052]: Fix an alignment build warning/error in function PyVectorcall_Function(). Patch by Andreas Schneider, Antoine Pitrou and Petr Viktorin.

Python 3.10.0 alpha 3

Release date: 2020-12-07

Security

bpo-40791 [https://bugs.python.org/issue?@action=redirect&bpo=40791]: Add volatile to the accumulator variable in hmac.compare_digest, making constant-time-defeating optimizations less likely.

Core and Builtins

bpo-42576 [https://bugs.python.org/issue?@action=redirect&bpo=42576]: types.GenericAlias will now raise a TypeError when attempting to initialize with a keyword argument. Previously, this would cause the interpreter to crash if the interpreter was compiled with debug symbols. This does not affect interpreters compiled for release. Patch by Ken Jin.

bpo-42536 [https://bugs.python.org/issue?@action=redirect&bpo=42536]: Several built-in and standard library types now ensure that their internal result tuples are always tracked by the garbage collector:

collections.OrderedDict.items()

dict.items()

enumerate()

functools.reduce()

itertools.combinations()

itertools.combinations_with_replacement()

itertools.permutations()

itertools.product()

itertools.zip_longest()

zip()

Previously, they could have become untracked by a prior garbage collection. Patch by Brandt Bucher.

bpo-42500 [https://bugs.python.org/issue?@action=redirect&bpo=42500]: Improve handling of exceptions near recursion limit. Converts a number of Fatal Errors in RecursionErrors.

bpo-42246 [https://bugs.python.org/issue?@action=redirect&bpo=42246]: PEP 626: After a return, the f_lineno attribute of a frame is always the last line executed.

bpo-42435 [https://bugs.python.org/issue?@action=redirect&bpo=42435]: Speed up comparison of bytes objects with non-bytes objects when option -b is specified. Speed up comparison of bytarray objects with non-buffer object.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _warnings extension module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]). Patch by Victor Stinner.

bpo-41686 [https://bugs.python.org/issue?@action=redirect&bpo=41686]: On Windows, the SIGINT event, _PyOS_SigintEvent(), is now created even if Python is configured to not install signal handlers (if PyConfig.install_signal_handlers equals to 0, or Py_InitializeEx(0)).

bpo-42381 [https://bugs.python.org/issue?@action=redirect&bpo=42381]: Allow assignment expressions in set literals and set comprehensions as per PEP 572. Patch by Pablo Galindo.

bpo-42202 [https://bugs.python.org/issue?@action=redirect&bpo=42202]: Change function parameters annotations internal representation to tuple of strings. Patch provided by Yurii Karabas.

bpo-42374 [https://bugs.python.org/issue?@action=redirect&bpo=42374]: Fix a regression introduced by the new parser, where an unparenthesized walrus operator was not allowed within generator expressions.

bpo-42316 [https://bugs.python.org/issue?@action=redirect&bpo=42316]: Allow an unparenthesized walrus in subscript indexes.

bpo-42349 [https://bugs.python.org/issue?@action=redirect&bpo=42349]: Make sure that the compiler front-end produces a well-formed control flow graph. Be more aggressive in the compiler back-end, as it is now safe to do so.

bpo-42296 [https://bugs.python.org/issue?@action=redirect&bpo=42296]: On Windows, fix a regression in signal handling which prevented to interrupt a program using CTRL+C. The signal handler can be run in a thread different than the Python thread, in which case the test deciding if the thread can handle signals is wrong.

bpo-42332 [https://bugs.python.org/issue?@action=redirect&bpo=42332]: types.GenericAlias objects can now be the targets of weakrefs.

bpo-42282 [https://bugs.python.org/issue?@action=redirect&bpo=42282]: Optimise constant subexpressions that appear as part of named expressions (previously the AST optimiser did not descend into named expressions). Patch by Nick Coghlan.

bpo-42266 [https://bugs.python.org/issue?@action=redirect&bpo=42266]: Fixed a bug with the LOAD_ATTR opcode cache that was not respecting monkey-patching a class-level attribute to make it a descriptor. Patch by Pablo Galindo.

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert queue to use heap types.

bpo-42246 [https://bugs.python.org/issue?@action=redirect&bpo=42246]: Improved accuracy of line tracing events and f_lineno attribute of Frame objects. See PEP 626 for details.

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert mmap to use heap types.

bpo-42233 [https://bugs.python.org/issue?@action=redirect&bpo=42233]: Allow GenericAlias objects to use union type expressions. This allows expressions like list[int] | dict[float, str] where previously a TypeError would have been thrown. This also fixes union type expressions not de-duplicating GenericAlias objects. (Contributed by Ken Jin in bpo-42233 [https://bugs.python.org/issue?@action=redirect&bpo=42233].)

bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131]: The import system triggers a ImportWarning when it falls back to using load_module().

Library

bpo-5054 [https://bugs.python.org/issue?@action=redirect&bpo=5054]: CGIHTTPRequestHandler.run_cgi() HTTP_ACCEPT improperly parsed. Replace the special purpose getallmatchingheaders with generic get_all method and add relevant tests.

Original Patch by Martin Panter. Modified by Senthil Kumaran.

bpo-42562 [https://bugs.python.org/issue?@action=redirect&bpo=42562]: Fix issue when dis failed to parse function that has no line numbers. Patch provided by Yurii Karabas.

bpo-17735 [https://bugs.python.org/issue?@action=redirect&bpo=17735]: inspect.findsource() now raises OSError instead of IndexError when co_lineno of a code object is greater than the file length. This can happen, for example, when a file is edited after it was imported. PR by Irit Katriel.

bpo-42116 [https://bugs.python.org/issue?@action=redirect&bpo=42116]: Fix handling of trailing comments by inspect.getsource().

bpo-42532 [https://bugs.python.org/issue?@action=redirect&bpo=42532]: Remove unexpected call of __bool__ when passing a spec_arg argument to a Mock.

bpo-38200 [https://bugs.python.org/issue?@action=redirect&bpo=38200]: Added itertools.pairwise()

bpo-41818 [https://bugs.python.org/issue?@action=redirect&bpo=41818]: Fix test_master_read() so that it succeeds on all platforms that either raise OSError or return b”” upon reading from master.

bpo-42487 [https://bugs.python.org/issue?@action=redirect&bpo=42487]: ChainMap.__iter__ no longer calls __getitem__ on underlying maps

bpo-42482 [https://bugs.python.org/issue?@action=redirect&bpo=42482]: TracebackException no longer holds a reference to the exception’s traceback object. Consequently, instances of TracebackException for equivalent but non-equal exceptions now compare as equal.

bpo-41818 [https://bugs.python.org/issue?@action=redirect&bpo=41818]: Make test_openpty() avoid unexpected success due to number of rows and/or number of columns being == 0.

bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392]: Remove loop parameter from asyncio.subprocess and asyncio.tasks functions. Patch provided by Yurii Karabas.

bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392]: Remove loop parameter from asyncio.open_connection and asyncio.start_server functions. Patch provided by Yurii Karabas.

bpo-28468 [https://bugs.python.org/issue?@action=redirect&bpo=28468]: Add platform.freedesktop_os_release() function to parse freedesktop.org os-release files.

bpo-42299 [https://bugs.python.org/issue?@action=redirect&bpo=42299]: Removed the formatter module, which was deprecated in Python 3.4. It is somewhat obsolete, little used, and not tested. It was originally scheduled to be removed in Python 3.6, but such removals were delayed until after Python 2.7 EOL. Existing users should copy whatever classes they use into their code. Patch by Donghee Na and and Terry J. Reedy.

bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131]: Deprecate zipimport.zipimporter.load_module() in favour of exec_module().

bpo-41818 [https://bugs.python.org/issue?@action=redirect&bpo=41818]: Updated tests for the pty library. test_basic() has been changed to test_openpty(); this additionally checks if slave termios and slave winsize are being set properly by pty.openpty(). In order to add support for FreeBSD, NetBSD, OpenBSD, and Darwin, this also adds test_master_read(), which demonstrates that pty.spawn() should not depend on an OSError to exit from its copy loop.

bpo-42392 [https://bugs.python.org/issue?@action=redirect&bpo=42392]: Remove loop parameter from __init__ in all asyncio.locks and asyncio.Queue classes. Patch provided by Yurii Karabas.

bpo-15450 [https://bugs.python.org/issue?@action=redirect&bpo=15450]: Make filecmp.dircmp respect subclassing. Now the filecmp.dircmp.subdirs behaves as expected when subclassing dircmp.

bpo-42413 [https://bugs.python.org/issue?@action=redirect&bpo=42413]: The exception socket.timeout is now an alias of TimeoutError.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Support signal module on VxWorks.

bpo-42406 [https://bugs.python.org/issue?@action=redirect&bpo=42406]: We fixed an issue in pickle.whichmodule in which importing multiprocessing could change the how pickle identifies which module an object belongs to, potentially breaking the unpickling of those objects.

bpo-42403 [https://bugs.python.org/issue?@action=redirect&bpo=42403]: Simplify the importlib external bootstrap code: importlib._bootstrap_external now uses regular imports to import builtin modules. When it is imported, the builtin __import__() function is already fully working and so can be used to import builtin modules like sys. Patch by Victor Stinner.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Convert _sre module types to heap types (PEP 384). Patch by Erlend E. Aasland.

bpo-42375 [https://bugs.python.org/issue?@action=redirect&bpo=42375]: subprocess module update for DragonFlyBSD support.

bpo-41713 [https://bugs.python.org/issue?@action=redirect&bpo=41713]: Port the _signal extension module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]). Patch by Victor Stinner and Mohamed Koubaa.

bpo-37205 [https://bugs.python.org/issue?@action=redirect&bpo=37205]: time.time(), time.perf_counter() and time.monotonic() functions can no longer fail with a Python fatal error, instead raise a regular Python exception on failure.

bpo-42328 [https://bugs.python.org/issue?@action=redirect&bpo=42328]: Fixed tkinter.ttk.Style.map(). The function accepts now the representation of the default state as empty sequence (as returned by Style.map()). The structure of the result is now the same on all platform and does not depend on the value of wantobjects.

bpo-42345 [https://bugs.python.org/issue?@action=redirect&bpo=42345]: Fix various issues with typing.Literal parameter handling (flatten, deduplicate, use type to cache key). Patch provided by Yurii Karabas.

bpo-37205 [https://bugs.python.org/issue?@action=redirect&bpo=37205]: time.perf_counter() on Windows and time.monotonic() on macOS are now system-wide. Previously, they used an offset computed at startup to reduce the precision loss caused by the float type. Use time.perf_counter_ns() and time.monotonic_ns() added in Python 3.7 to avoid this precision loss.

bpo-42318 [https://bugs.python.org/issue?@action=redirect&bpo=42318]: Fixed support of non-BMP characters in tkinter on macOS.

bpo-42350 [https://bugs.python.org/issue?@action=redirect&bpo=42350]: Fix the threading.Thread class at fork: do nothing if the thread is already stopped (ex: fork called at Python exit). Previously, an error was logged in the child process.

bpo-42333 [https://bugs.python.org/issue?@action=redirect&bpo=42333]: Port _ssl extension module to heap types.

bpo-42014 [https://bugs.python.org/issue?@action=redirect&bpo=42014]: The onerror callback from shutil.rmtree now receives correct function when os.open fails.

bpo-42237 [https://bugs.python.org/issue?@action=redirect&bpo=42237]: Fix os.sendfile() on illumos.

bpo-42308 [https://bugs.python.org/issue?@action=redirect&bpo=42308]: Add threading.__excepthook__ to allow retrieving the original value of threading.excepthook() in case it is set to a broken or a different value. Patch by Mario Corchero.

bpo-42131 [https://bugs.python.org/issue?@action=redirect&bpo=42131]: Implement PEP 451/spec methods on zipimport.zipimporter: find_spec(), create_module(), and exec_module().

This also allows for the documented deprecation of find_loader(), find_module(), and load_module().

bpo-41877 [https://bugs.python.org/issue?@action=redirect&bpo=41877]: Mock objects which are not unsafe will now raise an AttributeError if an attribute with the prefix asert, aseert, or assrt is accessed, in addition to this already happening for the prefixes assert or assret.

bpo-42264 [https://bugs.python.org/issue?@action=redirect&bpo=42264]: sqlite3.OptimizedUnicode has been undocumented and obsolete since Python 3.3, when it was made an alias to str. It is now deprecated, scheduled for removal in Python 3.12.

bpo-42251 [https://bugs.python.org/issue?@action=redirect&bpo=42251]: Added threading.gettrace() and threading.getprofile() to retrieve the functions set by threading.settrace() and threading.setprofile() respectively. Patch by Mario Corchero.

bpo-42249 [https://bugs.python.org/issue?@action=redirect&bpo=42249]: Fixed writing binary Plist files larger than 4 GiB.

bpo-42236 [https://bugs.python.org/issue?@action=redirect&bpo=42236]: On Unix, the os.device_encoding() function now returns 'UTF-8' rather than the device encoding if the Python UTF-8 Mode is enabled.

bpo-41754 [https://bugs.python.org/issue?@action=redirect&bpo=41754]: webbrowser: Ignore NotADirectoryError when calling xdg-settings.

bpo-42183 [https://bugs.python.org/issue?@action=redirect&bpo=42183]: Fix a stack overflow error for asyncio Task or Future repr().

The overflow occurs under some circumstances when a Task or Future recursively returns itself.

bpo-42140 [https://bugs.python.org/issue?@action=redirect&bpo=42140]: Improve asyncio.wait function to create the futures set just one time.

bpo-42133 [https://bugs.python.org/issue?@action=redirect&bpo=42133]: Update various modules in the stdlib to fall back on __spec__.loader when __loader__ isn’t defined on a module.

bpo-26131 [https://bugs.python.org/issue?@action=redirect&bpo=26131]: The load_module() methods found in importlib now trigger a DeprecationWarning.

bpo-39825 [https://bugs.python.org/issue?@action=redirect&bpo=39825]: Windows: Change sysconfig.get_config_var('EXT_SUFFIX') to the expected full platform_tag.extension format. Previously it was hard-coded to .pyd, now it is compatible with distutils.sysconfig and will result in something like .cp38-win_amd64.pyd. This brings windows into conformance with the other platforms.

bpo-26389 [https://bugs.python.org/issue?@action=redirect&bpo=26389]: The traceback.format_exception(), traceback.format_exception_only(), and traceback.print_exception() functions can now take an exception object as a positional-only argument.

bpo-41889 [https://bugs.python.org/issue?@action=redirect&bpo=41889]: Enum: fix regression involving inheriting a multiply inherited enum

bpo-41861 [https://bugs.python.org/issue?@action=redirect&bpo=41861]: Convert sqlite3 to use heap types (PEP 384). Patch by Erlend E. Aasland.

bpo-40624 [https://bugs.python.org/issue?@action=redirect&bpo=40624]: Added support for the XPath != operator in xml.etree

bpo-28850 [https://bugs.python.org/issue?@action=redirect&bpo=28850]: Fix pprint.PrettyPrinter.format() overrides being ignored for contents of small containers. The pprint._safe_repr() function was removed.

bpo-41625 [https://bugs.python.org/issue?@action=redirect&bpo=41625]: Expose the splice() as os.splice() in the os module. Patch by Pablo Galindo

bpo-34215 [https://bugs.python.org/issue?@action=redirect&bpo=34215]: Clarify the error message for asyncio.IncompleteReadError when expected is None.

bpo-41543 [https://bugs.python.org/issue?@action=redirect&bpo=41543]: Add async context manager support for contextlib.nullcontext.

bpo-21041 [https://bugs.python.org/issue?@action=redirect&bpo=21041]: pathlib.PurePath.parents now supports negative indexing. Patch contributed by Yaroslav Pankovych.

bpo-41332 [https://bugs.python.org/issue?@action=redirect&bpo=41332]: Added missing connect_accepted_socket() method to asyncio.AbstractEventLoop.

bpo-12800 [https://bugs.python.org/issue?@action=redirect&bpo=12800]: Extracting a symlink from a tarball should succeed and overwrite the symlink if it already exists. The fix is to remove the existing file or symlink before extraction. Based on patch by Chris AtLee, Jeffrey Kintscher, and Senthil Kumaran.

bpo-40968 [https://bugs.python.org/issue?@action=redirect&bpo=40968]: urllib.request and http.client now send http/1.1 ALPN extension during TLS handshake when no custom context is supplied.

bpo-41001 [https://bugs.python.org/issue?@action=redirect&bpo=41001]: Add os.eventfd() to provide a low level interface for Linux’s event notification file descriptor.

bpo-40816 [https://bugs.python.org/issue?@action=redirect&bpo=40816]: Add AsyncContextDecorator to contextlib to support async context manager as a decorator.

bpo-40550 [https://bugs.python.org/issue?@action=redirect&bpo=40550]: Fix time-of-check/time-of-action issue in subprocess.Popen.send_signal.

bpo-39411 [https://bugs.python.org/issue?@action=redirect&bpo=39411]: Add an is_async identifier to pyclbr’s Function objects. Patch by Batuhan Taskaya

bpo-35498 [https://bugs.python.org/issue?@action=redirect&bpo=35498]: Add slice support to pathlib.PurePath.parents.

Documentation

bpo-42238 [https://bugs.python.org/issue?@action=redirect&bpo=42238]: Tentative to deprecate make suspicious by first removing it from the CI and documentation builds, but keeping it around for manual uses.

bpo-42153 [https://bugs.python.org/issue?@action=redirect&bpo=42153]: Fix the URL for the IMAP protocol documents.

bpo-41028 [https://bugs.python.org/issue?@action=redirect&bpo=41028]: Language and version switchers, previously maintained in every cpython branches, are now handled by docsbuild-script.

Tests

bpo-41473 [https://bugs.python.org/issue?@action=redirect&bpo=41473]: Re-enable test_gdb on gdb 9.2 and newer: https://bugzilla.redhat.com/show_bug.cgi?id=1866884 bug is fixed in gdb 10.1.

bpo-42553 [https://bugs.python.org/issue?@action=redirect&bpo=42553]: Fix test_asyncio.test_call_later() race condition: don’t measure asyncio performance in the call_later() unit test. The test failed randomly on the CI.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix test_netrc on VxWorks: create temporary directories using temp_cwd().

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: skip test_getaddrinfo_ipv6_scopeid_symbolic and test_getnameinfo_ipv6_scopeid_symbolic on VxWorks

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: skip test_test of test_mailcap on VxWorks

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: add shell requirement for test_pipes

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: skip some tests related to fifo on VxWorks

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix test_doctest.py failures for VxWorks.

bpo-40754 [https://bugs.python.org/issue?@action=redirect&bpo=40754]: Include _testinternalcapi module in Windows installer for test suite

bpo-41561 [https://bugs.python.org/issue?@action=redirect&bpo=41561]: test_ssl: skip test_min_max_version_mismatch when TLS 1.0 is not available

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix os module failures for VxWorks RTOS.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix fifo test cases for VxWorks RTOS.

Build

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: remove libnet dependency from detect_socket() for VxWorks

bpo-42398 [https://bugs.python.org/issue?@action=redirect&bpo=42398]: Fix a race condition in “make regen-all” when make -jN option is used to run jobs in parallel. The clinic.py script now only use atomic write to write files. Moveover, generated files are now left unchanged if the content does not change, to not change the file modification time.

bpo-41617 [https://bugs.python.org/issue?@action=redirect&bpo=41617]: Fix building pycore_bitutils.h internal header on old clang version without __builtin_bswap16() (ex: Xcode 4.6.3 on Mac OS X 10.7). Patch by Joshua Root and Victor Stinner.

bpo-38823 [https://bugs.python.org/issue?@action=redirect&bpo=38823]: It is no longer possible to build the _ctypes extension module without wchar_t type: remove CTYPES_UNICODE macro. Anyway, the wchar_t type is required to build Python. Patch by Victor Stinner.

bpo-42087 [https://bugs.python.org/issue?@action=redirect&bpo=42087]: Support was removed for AIX 5.3 and below. See bpo-40680 [https://bugs.python.org/issue?@action=redirect&bpo=40680].

bpo-40998 [https://bugs.python.org/issue?@action=redirect&bpo=40998]: Addressed three compiler warnings found by undefined behavior sanitizer (ubsan).

Windows

bpo-42120 [https://bugs.python.org/issue?@action=redirect&bpo=42120]: Remove macro definition of copysign (to _copysign) in headers.

bpo-38506 [https://bugs.python.org/issue?@action=redirect&bpo=38506]: The Windows launcher now properly handles Python 3.10 when listing installed Python versions.

macOS

bpo-42504 [https://bugs.python.org/issue?@action=redirect&bpo=42504]: Fix build on macOS Big Sur when MACOSX_DEPLOYMENT_TARGET=11

bpo-41116 [https://bugs.python.org/issue?@action=redirect&bpo=41116]: Ensure distutils.unixxcompiler.find_library_file can find system provided libraries on macOS 11.

bpo-41100 [https://bugs.python.org/issue?@action=redirect&bpo=41100]: Add support for macOS 11 and Apple Silicon systems.

It is now possible to build “Universal 2” binaries using “–enable-universalsdk –with-universal-archs=universal2”.

Binaries build on later macOS versions can be deployed back to older versions (tested up to macOS 10.9), when using the correct deployment target. This is tested using Xcode 11 and later.

bpo-42232 [https://bugs.python.org/issue?@action=redirect&bpo=42232]: Added Darwin specific madvise options to mmap module.

bpo-38443 [https://bugs.python.org/issue?@action=redirect&bpo=38443]: The --enable-universalsdk and --with-universal-archs options for the configure script now check that the specified architectures can be used.

IDLE

bpo-42508 [https://bugs.python.org/issue?@action=redirect&bpo=42508]: Keep IDLE running on macOS. Remove obsolete workaround that prevented running files with shortcuts when using new universal2 installers built on macOS 11.

bpo-42426 [https://bugs.python.org/issue?@action=redirect&bpo=42426]: Fix reporting offset of the RE error in searchengine.

bpo-42415 [https://bugs.python.org/issue?@action=redirect&bpo=42415]: Get docstrings for IDLE calltips more often by using inspect.getdoc.

Tools/Demos

bpo-42212 [https://bugs.python.org/issue?@action=redirect&bpo=42212]: The smelly.py script now also checks the Python dynamic library and extension modules, not only the Python static library. Make also the script more verbose: explain what it does.

bpo-36310 [https://bugs.python.org/issue?@action=redirect&bpo=36310]: Allow Tools/i18n/pygettext.py to detect calls to gettext in f-strings.

C API

bpo-42423 [https://bugs.python.org/issue?@action=redirect&bpo=42423]: The PyType_FromSpecWithBases() and PyType_FromModuleAndSpec() functions now accept a single class as the bases argument.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port select extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _posixsubprocess extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _posixshmem extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _struct extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port spwd extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port gc extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _queue extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Convert Py_TYPE() and Py_SIZE() back to macros to allow using them as an l-value. Many third party C extension modules rely on the ability of using Py_TYPE() and Py_SIZE() to set an object type and size: Py_TYPE(obj) = type; and Py_SIZE(obj) = size;.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port symtable extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port grp and pwd extension modules to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _random extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _hashlib extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/])

bpo-41713 [https://bugs.python.org/issue?@action=redirect&bpo=41713]: Removed the undocumented PyOS_InitInterrupts() function. Initializing Python already implicitly installs signal handlers: see PyConfig.install_signal_handlers. Patch by Victor Stinner.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: The Py_TRASHCAN_BEGIN macro no longer accesses PyTypeObject attributes, but now can get the condition by calling the new private _PyTrash_cond() function which hides implementation details.

bpo-42260 [https://bugs.python.org/issue?@action=redirect&bpo=42260]: Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix(), Py_GetProgramFullPath(), Py_GetPythonHome() and Py_GetProgramName() functions now return NULL if called before Py_Initialize() (before Python is initialized). Use the new Python Initialization Configuration API to get the Python Path Configuration.. Patch by Victor Stinner.

bpo-42260 [https://bugs.python.org/issue?@action=redirect&bpo=42260]: The PyConfig_Read() function now only parses PyConfig.argv arguments once: PyConfig.parse_argv is set to 2 after arguments are parsed. Since Python arguments are strippped from PyConfig.argv, parsing arguments twice would parse the application options as Python options.

bpo-42262 [https://bugs.python.org/issue?@action=redirect&bpo=42262]: Added Py_NewRef() and Py_XNewRef() functions to increment the reference count of an object and return the object. Patch by Victor Stinner.

bpo-42260 [https://bugs.python.org/issue?@action=redirect&bpo=42260]: When Py_Initialize() is called twice, the second call now updates more sys attributes for the configuration, rather than only sys.argv. Patch by Victor Stinner.

bpo-41832 [https://bugs.python.org/issue?@action=redirect&bpo=41832]: The PyType_FromModuleAndSpec() function now accepts NULL tp_doc slot.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Added PyModule_AddObjectRef() function: similar to PyModule_AddObject() but don’t steal a reference to the value on success. Patch by Victor Stinner.

bpo-42171 [https://bugs.python.org/issue?@action=redirect&bpo=42171]: The METH_FASTCALL calling convention is added to the limited API. The functions PyModule_AddType(), PyType_FromModuleAndSpec(), PyType_GetModule() and PyType_GetModuleState() are added to the limited API on Windows.

bpo-42085 [https://bugs.python.org/issue?@action=redirect&bpo=42085]: Add dedicated entry to PyAsyncMethods for sending values

bpo-41073 [https://bugs.python.org/issue?@action=redirect&bpo=41073]: PyType_GetSlot() can now accept static types.

bpo-30459 [https://bugs.python.org/issue?@action=redirect&bpo=30459]: PyList_SET_ITEM(), PyTuple_SET_ITEM() and PyCell_SET() macros can no longer be used as l-value or r-value. For example, x = PyList_SET_ITEM(a, b, c) and PyList_SET_ITEM(a, b, c) = x now fail with a compiler error. It prevents bugs like if (PyList_SET_ITEM (a, b, c) < 0) ... test. Patch by Zackery Spytz and Victor Stinner.

Python 3.10.0 alpha 2

Release date: 2020-11-03

Security

bpo-42103 [https://bugs.python.org/issue?@action=redirect&bpo=42103]: Prevented potential DoS attack via CPU and RAM exhaustion when processing malformed Apple Property List files in binary format.

bpo-42051 [https://bugs.python.org/issue?@action=redirect&bpo=42051]: The plistlib module no longer accepts entity declarations in XML plist files to avoid XML vulnerabilities. This should not affect users as entity declarations are not used in regular plist files.

Core and Builtins

bpo-42236 [https://bugs.python.org/issue?@action=redirect&bpo=42236]: If the nl_langinfo(CODESET) function returns an empty string, Python now uses UTF-8 as the filesystem encoding. Patch by Victor Stinner.

bpo-42218 [https://bugs.python.org/issue?@action=redirect&bpo=42218]: Fixed a bug in the PEG parser that was causing crashes in debug mode. Now errors are checked in left-recursive rules to avoid cases where such errors do not get handled in time and appear as long-distance crashes in other places.

bpo-42214 [https://bugs.python.org/issue?@action=redirect&bpo=42214]: Fixed a possible crash in the PEG parser when checking for the ‘!=’ token in the barry_as_flufl rule. Patch by Pablo Galindo.

bpo-42206 [https://bugs.python.org/issue?@action=redirect&bpo=42206]: Propagate and raise the errors caused by PyAST_Validate() in the parser.

bpo-41796 [https://bugs.python.org/issue?@action=redirect&bpo=41796]: The ast module internal state is now per interpreter. Patch by Victor Stinner.

bpo-42143 [https://bugs.python.org/issue?@action=redirect&bpo=42143]: Fix handling of errors during creation of PyFunctionObject, which resulted in operations on uninitialized memory. Patch by Yonatan Goldschmidt.

bpo-41659 [https://bugs.python.org/issue?@action=redirect&bpo=41659]: Fix a bug in the parser, where a curly brace following a primary didn’t fail immediately. This led to invalid expressions like a {b} to throw a SyntaxError with a wrong offset, or invalid expressions ending with a curly brace like a { to not fail immediately in the REPL.

bpo-42150 [https://bugs.python.org/issue?@action=redirect&bpo=42150]: Fix possible buffer overflow in the new parser when checking for continuation lines. Patch by Pablo Galindo.

bpo-42123 [https://bugs.python.org/issue?@action=redirect&bpo=42123]: Run the parser two times. On the first run, disable all the rules that only generate better error messages to gain performance. If there’s a parse failure, run the parser a second time with those enabled.

bpo-42093 [https://bugs.python.org/issue?@action=redirect&bpo=42093]: The LOAD_ATTR instruction now uses new “per opcode cache” mechanism and it is about 36% faster now. Patch by Pablo Galindo and Yury Selivanov.

bpo-42030 [https://bugs.python.org/issue?@action=redirect&bpo=42030]: Support for the legacy AIX-specific shared library loading support has been removed. All versions of AIX since 4.3 have supported and defaulted to using the common Unix mechanism instead.

bpo-41984 [https://bugs.python.org/issue?@action=redirect&bpo=41984]: The garbage collector now tracks all user-defined classes. Patch by Brandt Bucher.

bpo-41993 [https://bugs.python.org/issue?@action=redirect&bpo=41993]: Fixed potential issues with removing not completely initialized module from sys.modules when import fails.

bpo-41979 [https://bugs.python.org/issue?@action=redirect&bpo=41979]: Star-unpacking is now allowed for with item’s targets in the PEG parser.

bpo-41974 [https://bugs.python.org/issue?@action=redirect&bpo=41974]: Removed special methods __int__, __float__, __floordiv__, __mod__, __divmod__, __rfloordiv__, __rmod__ and __rdivmod__ of the complex class. They always raised a TypeError.

bpo-41902 [https://bugs.python.org/issue?@action=redirect&bpo=41902]: Micro optimization when compute sq_item and mp_subscript of range. Patch by Donghee Na.

bpo-41894 [https://bugs.python.org/issue?@action=redirect&bpo=41894]: When loading a native module and a load failure occurs, prevent a possible UnicodeDecodeError when not running in a UTF-8 locale by decoding the load error message using the current locale’s encoding.

bpo-41902 [https://bugs.python.org/issue?@action=redirect&bpo=41902]: Micro optimization for range.index if step is 1. Patch by Donghee Na.

bpo-41435 [https://bugs.python.org/issue?@action=redirect&bpo=41435]: Add sys._current_exceptions() function to retrieve a dictionary mapping each thread’s identifier to the topmost exception currently active in that thread at the time the function is called.

bpo-38605 [https://bugs.python.org/issue?@action=redirect&bpo=38605]: Enable from __future__ import annotations (PEP 563 [https://peps.python.org/pep-0563/]) by default. The values found in __annotations__ dicts are now strings, for example {"x": "int"} instead of {"x": int}.

Library

bpo-35455 [https://bugs.python.org/issue?@action=redirect&bpo=35455]: On Solaris, thread_time() is now implemented with gethrvtime() because clock_gettime(CLOCK_THREAD_CPUTIME_ID) is not always available. Patch by Jakub Kulik.

bpo-42233 [https://bugs.python.org/issue?@action=redirect&bpo=42233]: The repr() of typing types containing Generic Alias Types previously did not show the parameterized types in the GenericAlias. They have now been changed to do so.

bpo-29566 [https://bugs.python.org/issue?@action=redirect&bpo=29566]: binhex.binhex() consistently writes macOS 9 line endings.

bpo-26789 [https://bugs.python.org/issue?@action=redirect&bpo=26789]: The logging.FileHandler class now keeps a reference to the builtin open() function to be able to open or reopen the file during Python finalization. Fix errors like: NameError: name 'open' is not defined. Patch by Victor Stinner.

bpo-42157 [https://bugs.python.org/issue?@action=redirect&bpo=42157]: Removed the unicodedata.ucnhash_CAPI attribute which was an internal PyCapsule object. The related private _PyUnicode_Name_CAPI structure was moved to the internal C API. Patch by Victor Stinner.

bpo-42157 [https://bugs.python.org/issue?@action=redirect&bpo=42157]: Convert the unicodedata extension module to the multiphase initialization API (PEP 489 [https://peps.python.org/pep-0489/]) and convert the unicodedata.UCD static type to a heap type. Patch by Mohamed Koubaa and Victor Stinner.

bpo-42146 [https://bugs.python.org/issue?@action=redirect&bpo=42146]: Fix memory leak in subprocess.Popen() in case an uid (gid) specified in user (group, extra_groups) overflows uid_t (gid_t).

bpo-42103 [https://bugs.python.org/issue?@action=redirect&bpo=42103]: InvalidFileException and RecursionError are now the only errors caused by loading malformed binary Plist file (previously ValueError and TypeError could be raised in some specific cases).

bpo-41490 [https://bugs.python.org/issue?@action=redirect&bpo=41490]: In importlib.resources, .path method is more aggressive about releasing handles to zipfile objects early, enabling use-cases like certifi to leave the context open but delete the underlying zip file.

bpo-41052 [https://bugs.python.org/issue?@action=redirect&bpo=41052]: Pickling heap types implemented in C with protocols 0 and 1 raises now an error instead of producing incorrect data.

bpo-42089 [https://bugs.python.org/issue?@action=redirect&bpo=42089]: In importlib.metadata.PackageNotFoundError, make reference to the package metadata being missing to improve the user experience.

bpo-41491 [https://bugs.python.org/issue?@action=redirect&bpo=41491]: plistlib: fix parsing XML plists with hexadecimal integer values

bpo-42065 [https://bugs.python.org/issue?@action=redirect&bpo=42065]: Fix an incorrectly formatted error from _codecs.charmap_decode() when called with a mapped value outside the range of valid Unicode code points. PR by Max Bernstein.

bpo-41966 [https://bugs.python.org/issue?@action=redirect&bpo=41966]: Fix pickling pure Python datetime.time subclasses. Patch by Dean Inwood.

bpo-19270 [https://bugs.python.org/issue?@action=redirect&bpo=19270]: sched.scheduler.cancel() will now cancel the correct event, if two events with same priority are scheduled for the same time. Patch by Bar Harel.

bpo-28660 [https://bugs.python.org/issue?@action=redirect&bpo=28660]: textwrap.wrap() now attempts to break long words after hyphens when break_long_words=True and break_on_hyphens=True.

bpo-35823 [https://bugs.python.org/issue?@action=redirect&bpo=35823]: Use vfork() instead of fork() for subprocess.Popen() on Linux to improve performance in cases where it is deemed safe.

bpo-42043 [https://bugs.python.org/issue?@action=redirect&bpo=42043]: Add support for zipfile.Path inheritance. zipfile.Path.is_file() now returns False for non-existent names. zipfile.Path objects now expose a .filename attribute and rely on that to resolve .name and .parent when the Path object is at the root of the zipfile.

bpo-42021 [https://bugs.python.org/issue?@action=redirect&bpo=42021]: Fix possible ref leaks in sqlite3 module init.

bpo-39101 [https://bugs.python.org/issue?@action=redirect&bpo=39101]: Fixed tests using IsolatedAsyncioTestCase from hanging on BaseExceptions.

bpo-41976 [https://bugs.python.org/issue?@action=redirect&bpo=41976]: Fixed a bug that was causing ctypes.util.find_library() to return None when triying to locate a library in an environment when gcc>=9 is available and ldconfig is not. Patch by Pablo Galindo

bpo-41943 [https://bugs.python.org/issue?@action=redirect&bpo=41943]: Fix bug where TestCase.assertLogs doesn’t correctly filter messages by level.

bpo-41923 [https://bugs.python.org/issue?@action=redirect&bpo=41923]: Implement PEP 613 [https://peps.python.org/pep-0613/], introducing typing.TypeAlias annotation.

bpo-41905 [https://bugs.python.org/issue?@action=redirect&bpo=41905]: A new function in abc: update_abstractmethods to re-calculate an abstract class’s abstract status. In addition, dataclass has been changed to call this function.

bpo-23706 [https://bugs.python.org/issue?@action=redirect&bpo=23706]: Added newline parameter to pathlib.Path.write_text().

bpo-41876 [https://bugs.python.org/issue?@action=redirect&bpo=41876]: Tkinter font class repr uses font name

bpo-41831 [https://bugs.python.org/issue?@action=redirect&bpo=41831]: str() for the type attribute of the tkinter.Event object always returns now the numeric code returned by Tk instead of the name of the event type.

bpo-39337 [https://bugs.python.org/issue?@action=redirect&bpo=39337]: encodings.normalize_encoding() now ignores non-ASCII characters.

bpo-41747 [https://bugs.python.org/issue?@action=redirect&bpo=41747]: Ensure all methods that generated from dataclasses.dataclass() objects now have the proper __qualname__ attribute referring to the class they belong to. Patch by Batuhan Taskaya.

bpo-30681 [https://bugs.python.org/issue?@action=redirect&bpo=30681]: Handle exceptions caused by unparsable date headers when using email “default” policy. Patch by Tim Bell, Georges Toth

bpo-41586 [https://bugs.python.org/issue?@action=redirect&bpo=41586]: Add F_SETPIPE_SZ and F_GETPIPE_SZ to fcntl module. Allow setting pipesize on subprocess.Popen.

bpo-41229 [https://bugs.python.org/issue?@action=redirect&bpo=41229]: Add contextlib.aclosing for deterministic cleanup of async generators which is analogous to contextlib.closing for non-async generators. Patch by Joongi Kim and John Belmonte.

bpo-16396 [https://bugs.python.org/issue?@action=redirect&bpo=16396]: Allow ctypes.wintypes to be imported on non-Windows systems.

bpo-4356 [https://bugs.python.org/issue?@action=redirect&bpo=4356]: Add a key function to the bisect module.

bpo-40592 [https://bugs.python.org/issue?@action=redirect&bpo=40592]: shutil.which() now ignores empty entries in PATHEXT instead of treating them as a match.

bpo-40492 [https://bugs.python.org/issue?@action=redirect&bpo=40492]: Fix --outfile for cProfile / profile not writing the output file in the original directory when the program being profiled changes the working directory. PR by Anthony Sottile.

bpo-34204 [https://bugs.python.org/issue?@action=redirect&bpo=34204]: The shelve module now uses pickle.DEFAULT_PROTOCOL by default instead of pickle protocol 3.

bpo-27321 [https://bugs.python.org/issue?@action=redirect&bpo=27321]: Fixed KeyError exception when flattening an email to a string attempts to replace a non-existent Content-Transfer-Encoding header.

bpo-38976 [https://bugs.python.org/issue?@action=redirect&bpo=38976]: The http.cookiejar module now supports the parsing of cookies in CURL-style cookiejar files through MozillaCookieJar on all platforms. Previously, such cookie entries would be silently ignored when loading a cookiejar with such entries.

Additionally, the HTTP Only attribute is persisted in the object, and will be correctly written to file if the MozillaCookieJar object is subsequently dumped.

Documentation

bpo-42061 [https://bugs.python.org/issue?@action=redirect&bpo=42061]: Document __format__ functionality for IP addresses.

bpo-41910 [https://bugs.python.org/issue?@action=redirect&bpo=41910]: Document the default implementation of object.__eq__.

bpo-42010 [https://bugs.python.org/issue?@action=redirect&bpo=42010]: Clarify that subscription expressions are also valid for certain classes and types in the standard library, and for user-defined classes and types if the classmethod __class_getitem__() is provided.

bpo-41805 [https://bugs.python.org/issue?@action=redirect&bpo=41805]: Documented generic alias type and types.GenericAlias. Also added an entry in glossary for generic types.

bpo-39693 [https://bugs.python.org/issue?@action=redirect&bpo=39693]: Fix tarfile’s extractfile documentation

bpo-39416 [https://bugs.python.org/issue?@action=redirect&bpo=39416]: Document some restrictions on the default string representations of numeric classes.

Tests

bpo-41739 [https://bugs.python.org/issue?@action=redirect&bpo=41739]: Fix test_logging.test_race_between_set_target_and_flush(): the test now waits until all threads complete to avoid leaking running threads.

bpo-41970 [https://bugs.python.org/issue?@action=redirect&bpo=41970]: Avoid a test failure in test_lib2to3 if the module has already imported at the time the test executes. Patch by Pablo Galindo.

bpo-41944 [https://bugs.python.org/issue?@action=redirect&bpo=41944]: Tests for CJK codecs no longer call eval() on content received via HTTP.

bpo-41306 [https://bugs.python.org/issue?@action=redirect&bpo=41306]: Fixed a failure in test_tk.test_widgets.ScaleTest happening when executing the test with Tk 8.6.10.

Build

bpo-38980 [https://bugs.python.org/issue?@action=redirect&bpo=38980]: Add -fno-semantic-interposition to both the compile and link line when building with --enable-optimizations. Patch by Victor Stinner and Pablo Galindo.

Windows

bpo-38439 [https://bugs.python.org/issue?@action=redirect&bpo=38439]: Updates the icons for IDLE in the Windows Store package.

bpo-38252 [https://bugs.python.org/issue?@action=redirect&bpo=38252]: Use 8-byte step to detect ASCII sequence in 64-bit Windows build.

bpo-39107 [https://bugs.python.org/issue?@action=redirect&bpo=39107]: Update Tcl and Tk to 8.6.10 in Windows installer.

bpo-41557 [https://bugs.python.org/issue?@action=redirect&bpo=41557]: Update Windows installer to use SQLite 3.33.0.

bpo-38324 [https://bugs.python.org/issue?@action=redirect&bpo=38324]: Avoid Unicode errors when accessing certain locale data on Windows.

macOS

bpo-41471 [https://bugs.python.org/issue?@action=redirect&bpo=41471]: Ignore invalid prefix lengths in system proxy excludes.

IDLE

bpo-33987 [https://bugs.python.org/issue?@action=redirect&bpo=33987]: Mostly finish using ttk widgets, mainly for editor, settings, and searches. Some patches by Mark Roseman.

bpo-40511 [https://bugs.python.org/issue?@action=redirect&bpo=40511]: Typing opening and closing parentheses inside the parentheses of a function call will no longer cause unnecessary “flashing” off and on of an existing open call-tip, e.g. when typed in a string literal.

bpo-38439 [https://bugs.python.org/issue?@action=redirect&bpo=38439]: Add a 256×256 pixel IDLE icon to the Windows .ico file. Created by Andrew Clover. Remove the low-color gif variations from the .ico file.

C API

bpo-42157 [https://bugs.python.org/issue?@action=redirect&bpo=42157]: The private _PyUnicode_Name_CAPI structure of the PyCapsule API unicodedata.ucnhash_CAPI has been moved to the internal C API. Patch by Victor Stinner.

bpo-42015 [https://bugs.python.org/issue?@action=redirect&bpo=42015]: Fix potential crash in deallocating method objects when dynamically allocated PyMethodDef’s lifetime is managed through the self argument of a PyCFunction.

bpo-40423 [https://bugs.python.org/issue?@action=redirect&bpo=40423]: The subprocess module and os.closerange will now use the close_range(low, high, flags) syscall when it is available for more efficient closing of ranges of descriptors.

bpo-41845 [https://bugs.python.org/issue?@action=redirect&bpo=41845]: PyObject_GenericGetDict() is available again in the limited API when targeting 3.10 or later.

bpo-40422 [https://bugs.python.org/issue?@action=redirect&bpo=40422]: Add _Py_closerange function to provide performant closing of a range of file descriptors.

bpo-41986 [https://bugs.python.org/issue?@action=redirect&bpo=41986]: Py_FileSystemDefaultEncodeErrors and Py_UTF8Mode are available again in limited API.

bpo-41756 [https://bugs.python.org/issue?@action=redirect&bpo=41756]: Add PyIter_Send function to allow sending value into generator/coroutine/iterator without raising StopIteration exception to signal return.

bpo-41784 [https://bugs.python.org/issue?@action=redirect&bpo=41784]: Added PyUnicode_AsUTF8AndSize to the limited C API.

Python 3.10.0 alpha 1

Release date: 2020-10-05

Security

bpo-41304 [https://bugs.python.org/issue?@action=redirect&bpo=41304]: Fixes python3x._pth being ignored on Windows, caused by the fix for bpo-29778 [https://bugs.python.org/issue?@action=redirect&bpo=29778] (CVE 2020-15801 [https://www.cve.org/CVERecord?id=CVE-2020-15801]).

bpo-41162 [https://bugs.python.org/issue?@action=redirect&bpo=41162]: Audit hooks are now cleared later during finalization to avoid missing events.

bpo-29778 [https://bugs.python.org/issue?@action=redirect&bpo=29778]: Ensure python3.dll is loaded from correct locations when Python is embedded (CVE 2020-15523 [https://www.cve.org/CVERecord?id=CVE-2020-15523]).

bpo-41004 [https://bugs.python.org/issue?@action=redirect&bpo=41004]: The __hash__() methods of ipaddress.IPv4Interface and ipaddress.IPv6Interface incorrectly generated constant hash values of 32 and 128 respectively. This resulted in always causing hash collisions. The fix uses hash() to generate hash values for the tuple of (address, mask length, network address).

bpo-39603 [https://bugs.python.org/issue?@action=redirect&bpo=39603]: Prevent http header injection by rejecting control characters in http.client.putrequest(…).

Core and Builtins

bpo-41909 [https://bugs.python.org/issue?@action=redirect&bpo=41909]: Fixed stack overflow in issubclass() and isinstance() when getting the __bases__ attribute leads to infinite recursion.

bpo-41922 [https://bugs.python.org/issue?@action=redirect&bpo=41922]: Speed up calls to reversed() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-41873 [https://bugs.python.org/issue?@action=redirect&bpo=41873]: Calls to float() are now faster due to the vectorcall calling convention. Patch by Dennis Sweeney.

bpo-41870 [https://bugs.python.org/issue?@action=redirect&bpo=41870]: Speed up calls to bool() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _bisect module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39934 [https://bugs.python.org/issue?@action=redirect&bpo=39934]: Correctly count control blocks in ‘except’ in compiler. Ensures that a syntax error, rather a fatal error, occurs for deeply nested, named exception handlers.

bpo-41780 [https://bugs.python.org/issue?@action=redirect&bpo=41780]: Fix __dir__() of types.GenericAlias. Patch by Batuhan Taskaya.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _lsprof extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the cmath extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _scproxy extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the termios extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Convert the _sha256 extension module types to heap types.

bpo-41690 [https://bugs.python.org/issue?@action=redirect&bpo=41690]: Fix a possible stack overflow in the parser when parsing functions and classes with a huge amount of arguments. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _overlapped extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _curses_panel extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _opcode extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-41681 [https://bugs.python.org/issue?@action=redirect&bpo=41681]: Fixes the wrong error description in the error raised by using 2 , in format string in f-string and str.format().

bpo-41675 [https://bugs.python.org/issue?@action=redirect&bpo=41675]: The implementation of signal.siginterrupt() now uses sigaction() (if it is available in the system) instead of the deprecated siginterrupt(). Patch by Pablo Galindo.

bpo-41670 [https://bugs.python.org/issue?@action=redirect&bpo=41670]: Prevent line trace being skipped on platforms not compiled with USE_COMPUTED_GOTOS. Fixes issue where some lines nested within a try-except block were not being traced on Windows.

bpo-41654 [https://bugs.python.org/issue?@action=redirect&bpo=41654]: Fix a crash that occurred when destroying subclasses of MemoryError. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the zlib extension module to multi-phase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-41631 [https://bugs.python.org/issue?@action=redirect&bpo=41631]: The _ast module uses again a global state. Using a module state per module instance is causing subtle practical problems. For example, the Mercurial project replaces the __import__() function to implement lazy import, whereas Python expected that import _ast always return a fully initialized _ast module.

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert _operator to use PyType_FromSpec().

bpo-1653741 [https://bugs.python.org/issue?@action=redirect&bpo=1653741]: Port _sha3 to multi-phase init. Convert static types to heap types.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _blake2 extension module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-41533 [https://bugs.python.org/issue?@action=redirect&bpo=41533]: Free the stack allocated in va_build_stack if do_mkstack fails and the stack is not a small_stack.

bpo-41531 [https://bugs.python.org/issue?@action=redirect&bpo=41531]: Fix a bug that was dropping keys when compiling dict literals with more than 0xFFFF elements. Patch by Pablo Galindo.

bpo-41525 [https://bugs.python.org/issue?@action=redirect&bpo=41525]: The output of python --help contains now only ASCII characters.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _sha1, _sha512, and _md5 extension modules to multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-41431 [https://bugs.python.org/issue?@action=redirect&bpo=41431]: Optimize dict_merge() for copying dict (e.g. dict(d) and {}.update(d)).

bpo-41428 [https://bugs.python.org/issue?@action=redirect&bpo=41428]: Implement PEP 604. This supports (int | str) etc. in place of Union[str, int].

bpo-41340 [https://bugs.python.org/issue?@action=redirect&bpo=41340]: Removed fallback implementation for strdup.

bpo-38156 [https://bugs.python.org/issue?@action=redirect&bpo=38156]: Handle interrupts that come after EOF correctly in PyOS_StdioReadline.

bpo-41342 [https://bugs.python.org/issue?@action=redirect&bpo=41342]: round() with integer argument is now faster (9–60%).

bpo-41334 [https://bugs.python.org/issue?@action=redirect&bpo=41334]: Constructors str(), bytes() and bytearray() are now faster (around 30–40% for small objects).

bpo-41295 [https://bugs.python.org/issue?@action=redirect&bpo=41295]: Resolve a regression in CPython 3.8.4 where defining “__setattr__” in a multi-inheritance setup and calling up the hierarchy chain could fail if builtins/extension types were involved in the base types.

bpo-41323 [https://bugs.python.org/issue?@action=redirect&bpo=41323]: Bytecode optimizations are performed directly on the control flow graph. This will result in slightly more compact code objects in some circumstances.

bpo-41247 [https://bugs.python.org/issue?@action=redirect&bpo=41247]: Always cache the running loop holder when running asyncio.set_running_loop.

bpo-41252 [https://bugs.python.org/issue?@action=redirect&bpo=41252]: Fix incorrect refcounting in _ssl.c’s _servername_callback().

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port multiprocessing to multi-phase initialization

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port winapi to multiphase initialization

bpo-41215 [https://bugs.python.org/issue?@action=redirect&bpo=41215]: Use non-NULL default values in the PEG parser keyword list to overcome a bug that was preventing Python from being properly compiled when using the XLC compiler. Patch by Pablo Galindo.

bpo-41218 [https://bugs.python.org/issue?@action=redirect&bpo=41218]: Python 3.8.3 had a regression where compiling with ast.PyCF_ALLOW_TOP_LEVEL_AWAIT would aggressively mark list comprehension with CO_COROUTINE. Now only list comprehension making use of async/await will tagged as so.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port faulthandler to multiphase initialization.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port sha256 to multiphase initialization

bpo-41175 [https://bugs.python.org/issue?@action=redirect&bpo=41175]: Guard against a NULL pointer dereference within bytearrayobject triggered by the bytearray() + bytearray() operation.

bpo-41100 [https://bugs.python.org/issue?@action=redirect&bpo=41100]: add arm64 to the allowable Mac OS arches in mpdecimal.h

bpo-41094 [https://bugs.python.org/issue?@action=redirect&bpo=41094]: Fix decoding errors with audit when open files with non-ASCII names on non-UTF-8 locale.

bpo-39960 [https://bugs.python.org/issue?@action=redirect&bpo=39960]: The “hackcheck” that prevents sneaking around a type’s __setattr__() by calling the superclass method was rewritten to allow C implemented heap types.

bpo-41084 [https://bugs.python.org/issue?@action=redirect&bpo=41084]: Prefix the error message with ‘f-string: ‘, when parsing an f-string expression which throws a SyntaxError.

bpo-40521 [https://bugs.python.org/issue?@action=redirect&bpo=40521]: Empty frozensets are no longer singletons.

bpo-41076 [https://bugs.python.org/issue?@action=redirect&bpo=41076]: Pre-feed the parser with the location of the f-string expression, not the f-string itself, which allows us to skip the shifting of the AST node locations after the parsing is completed.

bpo-41056 [https://bugs.python.org/issue?@action=redirect&bpo=41056]: Fixes a reference to deallocated stack space during startup when constructing sys.path involving a relative symlink when code was supplied via -c. (discovered via Coverity)

bpo-41061 [https://bugs.python.org/issue?@action=redirect&bpo=41061]: Fix incorrect expressions and asserts in hashtable code and tests.

bpo-41052 [https://bugs.python.org/issue?@action=redirect&bpo=41052]: Opt out serialization/deserialization for _random.Random

bpo-40939 [https://bugs.python.org/issue?@action=redirect&bpo=40939]: Rename PyPegen* functions to PyParser*, so that we can remove the old set of PyParser* functions that were using the old parser, but keep everything backwards-compatible.

bpo-35975 [https://bugs.python.org/issue?@action=redirect&bpo=35975]: Stefan Behnel reported that cf_feature_version is used even when PyCF_ONLY_AST is not set. This is against the intention and against the documented behavior, so it’s been fixed.

bpo-40939 [https://bugs.python.org/issue?@action=redirect&bpo=40939]: Remove the remaining files from the old parser and the symbol module.

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert _bz2 to use PyType_FromSpec().

bpo-41006 [https://bugs.python.org/issue?@action=redirect&bpo=41006]: The encodings.latin_1 module is no longer imported at startup. Now it is only imported when it is the filesystem encoding or the stdio encoding.

bpo-40636 [https://bugs.python.org/issue?@action=redirect&bpo=40636]: zip() now supports PEP 618 [https://peps.python.org/pep-0618/]’s strict parameter, which raises a ValueError if the arguments are exhausted at different lengths. Patch by Brandt Bucher.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _gdbm to multiphase initialization.

bpo-40985 [https://bugs.python.org/issue?@action=redirect&bpo=40985]: Fix a bug that caused the SyntaxError text to be empty when a file ends with a line ending in a line continuation character (i.e. backslash). The error text should contain the text of the last line.

bpo-40958 [https://bugs.python.org/issue?@action=redirect&bpo=40958]: Fix a possible buffer overflow in the PEG parser when gathering information for emitting syntax errors. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _dbm to multiphase initialization.

bpo-40957 [https://bugs.python.org/issue?@action=redirect&bpo=40957]: Fix refleak in _Py_fopen_obj() when PySys_Audit() fails

bpo-40950 [https://bugs.python.org/issue?@action=redirect&bpo=40950]: Add a state to the nis module (PEP 3121 [https://peps.python.org/pep-3121/]) and apply the multiphase initialization. Patch by Donghee Na.

bpo-40947 [https://bugs.python.org/issue?@action=redirect&bpo=40947]: The Python Path Configuration now takes PyConfig.platlibdir in account.

bpo-40939 [https://bugs.python.org/issue?@action=redirect&bpo=40939]: Remove the old parser, the parser module and all associated support code, command-line options and environment variables. Patch by Pablo Galindo.

bpo-40847 [https://bugs.python.org/issue?@action=redirect&bpo=40847]: Fix a bug where a line with only a line continuation character is not considered a blank line at tokenizer level. In such cases, more than a single NEWLINE token was emitted. The old parser was working around the issue, but the new parser threw a SyntaxError for valid input due to this. For example, an empty line following a line continuation character was interpreted as a SyntaxError.

bpo-40890 [https://bugs.python.org/issue?@action=redirect&bpo=40890]: Each dictionary view now has a mapping attribute that provides a types.MappingProxyType wrapping the original dictionary. Patch contributed by Dennis Sweeney.

bpo-40889 [https://bugs.python.org/issue?@action=redirect&bpo=40889]: Improved the performance of symmetric difference operations on dictionary item views. Patch by Dennis Sweeney.

bpo-40904 [https://bugs.python.org/issue?@action=redirect&bpo=40904]: Fix possible segfault in the new PEG parser when parsing f-string containing yield statements with no value (f"{yield}"). Patch by Pablo Galindo

bpo-40903 [https://bugs.python.org/issue?@action=redirect&bpo=40903]: Fixed a possible segfault in the new PEG parser when producing error messages for invalid assignments of the form p=p=. Patch by Pablo Galindo

bpo-40880 [https://bugs.python.org/issue?@action=redirect&bpo=40880]: Fix invalid memory read in the new parser when checking newlines in string literals. Patch by Pablo Galindo.

bpo-40883 [https://bugs.python.org/issue?@action=redirect&bpo=40883]: Fix memory leak in when parsing f-strings in the new parser. Patch by Pablo Galindo

bpo-40870 [https://bugs.python.org/issue?@action=redirect&bpo=40870]: Raise ValueError when validating custom AST’s where the constants True, False and None are used within a ast.Name node.

bpo-40854 [https://bugs.python.org/issue?@action=redirect&bpo=40854]: Allow overriding sys.platlibdir via a new PYTHONPLATLIBDIR environment variable.

bpo-40826 [https://bugs.python.org/issue?@action=redirect&bpo=40826]: Fix GIL usage in PyOS_Readline(): lock the GIL to set an exception and pass the Python thread state when checking if there is a pending signal.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port fcntl to multiphase initialization.

bpo-19468 [https://bugs.python.org/issue?@action=redirect&bpo=19468]: Delete unnecessary instance check in importlib.reload(). Patch by Furkan Önder.

bpo-40824 [https://bugs.python.org/issue?@action=redirect&bpo=40824]: Unexpected errors in calling the __iter__ method are no longer masked by TypeError in the in operator and functions contains(), indexOf() and countOf() of the operator module.

bpo-40792 [https://bugs.python.org/issue?@action=redirect&bpo=40792]: Attributes start, stop and step of the range object now always has exact type int. Previously, they could have been an instance of a subclass of int.

bpo-40780 [https://bugs.python.org/issue?@action=redirect&bpo=40780]: Fix a corner case where g-style string formatting of a float failed to remove trailing zeros.

bpo-38964 [https://bugs.python.org/issue?@action=redirect&bpo=38964]: When there’s a SyntaxError in the expression part of an fstring, the filename attribute of the SyntaxError gets correctly set to the name of the file the fstring resides in.

bpo-40750 [https://bugs.python.org/issue?@action=redirect&bpo=40750]: Support the “-d” debug flag in the new PEG parser. Patch by Pablo Galindo

bpo-40217 [https://bugs.python.org/issue?@action=redirect&bpo=40217]: Instances of types created with PyType_FromSpecWithBases() will no longer automatically visit their class object when traversing references in the garbage collector. The user is expected to manually visit the object’s class. Patch by Pablo Galindo.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Py_TYPE() is changed to the inline static function. Patch by Donghee Na.

bpo-40696 [https://bugs.python.org/issue?@action=redirect&bpo=40696]: Fix a hang that can arise after generator.throw() due to a cycle in the exception context chain.

bpo-40521 [https://bugs.python.org/issue?@action=redirect&bpo=40521]: Each interpreter now its has own free lists, singletons and caches:

Free lists: float, tuple, list, dict, frame, context, asynchronous generator, MemoryError.

Singletons: empty tuple, empty bytes string, empty Unicode string, single byte character, single Unicode (latin1) character.

Slice cache.

They are no longer shared by all interpreters.

bpo-40679 [https://bugs.python.org/issue?@action=redirect&bpo=40679]: Certain TypeError messages about missing or extra arguments now include the function’s qualified name. Patch by Dennis Sweeney.

bpo-29590 [https://bugs.python.org/issue?@action=redirect&bpo=29590]: Make the stack trace correct after calling generator.throw() on a generator that has yielded from a yield from.

bpo-4022 [https://bugs.python.org/issue?@action=redirect&bpo=4022]: Improve performance of generators by not raising internal StopIteration.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port mmap to multiphase initialization.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _lzma to multiphase initialization.

bpo-37999 [https://bugs.python.org/issue?@action=redirect&bpo=37999]: Builtin and extension functions that take integer arguments no longer accept Decimals, Fractions and other objects that can be converted to integers only with a loss (e.g. that have the __int__() method but do not have the __index__() method).

bpo-29882 [https://bugs.python.org/issue?@action=redirect&bpo=29882]: Add int.bit_count(), counting the number of ones in the binary representation of an integer. Patch by Niklas Fiekas.

bpo-36982 [https://bugs.python.org/issue?@action=redirect&bpo=36982]: Use ncurses extended color functions when available to support terminals with 256 colors, and add the new function curses.has_extended_color_support() to indicate whether extended color support is provided by the underlying ncurses library.

bpo-19569 [https://bugs.python.org/issue?@action=redirect&bpo=19569]: Add the private macros _Py_COMP_DIAG_PUSH, _Py_COMP_DIAG_IGNORE_DEPR_DECLS, and _Py_COMP_DIAG_POP.

bpo-26680 [https://bugs.python.org/issue?@action=redirect&bpo=26680]: The int type now supports the x.is_integer() method for compatibility with float.

Library

bpo-41900 [https://bugs.python.org/issue?@action=redirect&bpo=41900]: C14N 2.0 serialisation in xml.etree.ElementTree failed for unprefixed attributes when a default namespace was defined.

bpo-41887 [https://bugs.python.org/issue?@action=redirect&bpo=41887]: Strip leading spaces and tabs on ast.literal_eval(). Also document stripping of spaces and tabs for eval().

bpo-41773 [https://bugs.python.org/issue?@action=redirect&bpo=41773]: Note in documentation that random.choices() doesn’t support non-finite weights, raise ValueError when given non-finite weights.

bpo-41840 [https://bugs.python.org/issue?@action=redirect&bpo=41840]: Fix a bug in the symtable module that was causing module-scope global variables to not be reported as both local and global. Patch by Pablo Galindo.

bpo-41842 [https://bugs.python.org/issue?@action=redirect&bpo=41842]: Add codecs.unregister() function to unregister a codec search function.

bpo-40564 [https://bugs.python.org/issue?@action=redirect&bpo=40564]: In zipfile.Path, mutate the passed ZipFile object type instead of making a copy. Prevents issues when both the local copy and the caller’s copy attempt to close the same file handle.

bpo-40670 [https://bugs.python.org/issue?@action=redirect&bpo=40670]: More reliable validation of statements in timeit.Timer. It now accepts “empty” statements (only whitespaces and comments) and rejects misindentent statements.

bpo-41833 [https://bugs.python.org/issue?@action=redirect&bpo=41833]: The threading.Thread constructor now uses the target name if the target argument is specified but the name argument is omitted.

bpo-41817 [https://bugs.python.org/issue?@action=redirect&bpo=41817]: fix tkinter.EventType Enum so all members are strings, and none are tuples

bpo-41810 [https://bugs.python.org/issue?@action=redirect&bpo=41810]: types.EllipsisType, types.NotImplementedType and types.NoneType have been reintroduced, providing a new set of types readily interpretable by static type checkers.

bpo-41815 [https://bugs.python.org/issue?@action=redirect&bpo=41815]: Fix SQLite3 segfault when backing up closed database. Patch contributed by Peter David McCormick.

bpo-41816 [https://bugs.python.org/issue?@action=redirect&bpo=41816]: StrEnum added: it ensures that all members are already strings or string candidates

bpo-41517 [https://bugs.python.org/issue?@action=redirect&bpo=41517]: fix bug allowing Enums to be extended via multiple inheritance

bpo-39587 [https://bugs.python.org/issue?@action=redirect&bpo=39587]: use the correct mix-in data type when constructing Enums

bpo-41792 [https://bugs.python.org/issue?@action=redirect&bpo=41792]: Add is_typeddict function to typing.py to check if a type is a TypedDict class

Previously there was no way to check that without using private API. See the relevant issue in python/typing [https://github.com/python/typing/issues/751].

bpo-41789 [https://bugs.python.org/issue?@action=redirect&bpo=41789]: Honor object overrides in Enum class creation (specifically, __str__, __repr__, __format__, and __reduce_ex__).

bpo-32218 [https://bugs.python.org/issue?@action=redirect&bpo=32218]: enum.Flag and enum.IntFlag members are now iterable.

bpo-39651 [https://bugs.python.org/issue?@action=redirect&bpo=39651]: Fix a race condition in the call_soon_threadsafe() method of asyncio.ProactorEventLoop: do nothing if the self-pipe socket has been closed.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the mashal extension module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port the _string extension module to the multi-phase initialization API (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-41732 [https://bugs.python.org/issue?@action=redirect&bpo=41732]: Added an iterator to memoryview.

bpo-41720 [https://bugs.python.org/issue?@action=redirect&bpo=41720]: Fixed turtle.Vec2D.__rmul__() for arguments which are not int or float.

bpo-41696 [https://bugs.python.org/issue?@action=redirect&bpo=41696]: Fix handling of debug mode in asyncio.run(). This allows setting PYTHONASYNCIODEBUG or -X dev to enable asyncio debug mode when using asyncio.run().

bpo-41687 [https://bugs.python.org/issue?@action=redirect&bpo=41687]: Fix implementation of sendfile to be compatible with Solaris.

bpo-41662 [https://bugs.python.org/issue?@action=redirect&bpo=41662]: No longer override exceptions raised in __len__() of a sequence of parameters in sqlite3 with ProgrammingError.

bpo-39010 [https://bugs.python.org/issue?@action=redirect&bpo=39010]: Restarting a ProactorEventLoop on Windows no longer logs spurious ConnectionResetErrors.

bpo-41638 [https://bugs.python.org/issue?@action=redirect&bpo=41638]: ProgrammingError message for absent parameter in sqlite3 contains now the name of the parameter instead of its index when parameters are supplied as a dict.

bpo-41662 [https://bugs.python.org/issue?@action=redirect&bpo=41662]: Fixed crash when mutate list of parameters during iteration in sqlite3.

bpo-41513 [https://bugs.python.org/issue?@action=redirect&bpo=41513]: Improved the accuracy of math.hypot(). Internally, each step is computed with extra precision so that the result is now almost always correctly rounded.

bpo-41609 [https://bugs.python.org/issue?@action=redirect&bpo=41609]: The pdb whatis command correctly reports instance methods as ‘Method’ rather than ‘Function’.

bpo-39994 [https://bugs.python.org/issue?@action=redirect&bpo=39994]: Fixed pprint’s handling of dict subclasses that override __repr__.

bpo-32751 [https://bugs.python.org/issue?@action=redirect&bpo=32751]: When cancelling the task due to a timeout, asyncio.wait_for() will now wait until the cancellation is complete also in the case when timeout is <= 0, like it does with positive timeouts.

bpo-37658 [https://bugs.python.org/issue?@action=redirect&bpo=37658]: asyncio.wait_for() now properly handles races between cancellation of itself and the completion of the wrapped awaitable.

bpo-40782 [https://bugs.python.org/issue?@action=redirect&bpo=40782]: Change the method asyncio.AbstractEventLoop.run_in_executor to not be a coroutine.

bpo-41520 [https://bugs.python.org/issue?@action=redirect&bpo=41520]: Fix codeop regression that prevented turning compile warnings into errors.

bpo-41528 [https://bugs.python.org/issue?@action=redirect&bpo=41528]: turtle uses math module functions to convert degrees to radians and vice versa and to calculate vector norm

bpo-41513 [https://bugs.python.org/issue?@action=redirect&bpo=41513]: Minor algorithmic improvement to math.hypot() and math.dist() giving small gains in speed and accuracy.

bpo-41503 [https://bugs.python.org/issue?@action=redirect&bpo=41503]: Fixed a race between setTarget and flush in logging.handlers.MemoryHandler.

bpo-41497 [https://bugs.python.org/issue?@action=redirect&bpo=41497]: Fix potential UnicodeDecodeError in dis module.

bpo-41467 [https://bugs.python.org/issue?@action=redirect&bpo=41467]: On Windows, fix asyncio recv_into() return value when the socket/pipe is closed (BrokenPipeError): return 0 rather than an empty byte string (b'').

bpo-41425 [https://bugs.python.org/issue?@action=redirect&bpo=41425]: Make tkinter doc example runnable.

bpo-41421 [https://bugs.python.org/issue?@action=redirect&bpo=41421]: Make an algebraic simplification to random.paretovariate(). It now is slightly less subject to round-off error and is slightly faster. Inputs that used to cause ZeroDivisionError now cause an OverflowError instead.

bpo-41440 [https://bugs.python.org/issue?@action=redirect&bpo=41440]: Add os.cpu_count() support for VxWorks RTOS.

bpo-41316 [https://bugs.python.org/issue?@action=redirect&bpo=41316]: Fix the tarfile module to write only basename of TAR file to GZIP compression header.

bpo-41384 [https://bugs.python.org/issue?@action=redirect&bpo=41384]: Raise TclError instead of TypeError when an unknown option is passed to tkinter.OptionMenu.

bpo-41317 [https://bugs.python.org/issue?@action=redirect&bpo=41317]: Use add_done_callback() in asyncio.loop.sock_accept() to unsubscribe reader early on cancellation.

bpo-41364 [https://bugs.python.org/issue?@action=redirect&bpo=41364]: Reduce import overhead of uuid.

bpo-35328 [https://bugs.python.org/issue?@action=redirect&bpo=35328]: Set the environment variable VIRTUAL_ENV_PROMPT at venv activation.

bpo-41341 [https://bugs.python.org/issue?@action=redirect&bpo=41341]: Recursive evaluation of typing.ForwardRef in get_type_hints.

bpo-41344 [https://bugs.python.org/issue?@action=redirect&bpo=41344]: Prevent creating shared_memory.SharedMemory objects with size=0.

bpo-41333 [https://bugs.python.org/issue?@action=redirect&bpo=41333]: collections.OrderedDict.pop() is now 2 times faster.

bpo-41288 [https://bugs.python.org/issue?@action=redirect&bpo=41288]: Unpickling invalid NEWOBJ_EX opcode with the C implementation raises now UnpicklingError instead of crashing.

bpo-39017 [https://bugs.python.org/issue?@action=redirect&bpo=39017]: Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE 2019-20907 [https://www.cve.org/CVERecord?id=CVE-2019-20907]).

bpo-41273 [https://bugs.python.org/issue?@action=redirect&bpo=41273]: Speed up any transport using _ProactorReadPipeTransport by calling recv_into instead of recv, thus not creating a new buffer for each recv call in the transport’s read loop.

bpo-41235 [https://bugs.python.org/issue?@action=redirect&bpo=41235]: Fix the error handling in ssl.SSLContext.load_dh_params().

bpo-41207 [https://bugs.python.org/issue?@action=redirect&bpo=41207]: In distutils.spawn, restore expectation that DistutilsExecError is raised when the command is not found.

bpo-29727 [https://bugs.python.org/issue?@action=redirect&bpo=29727]: Register array.array as a MutableSequence. Patch by Pablo Galindo.

bpo-39168 [https://bugs.python.org/issue?@action=redirect&bpo=39168]: Remove the __new__ method of typing.Generic.

bpo-41194 [https://bugs.python.org/issue?@action=redirect&bpo=41194]: Fix a crash in the _ast module: it can no longer be loaded more than once. It now uses a global state rather than a module state.

bpo-41195 [https://bugs.python.org/issue?@action=redirect&bpo=41195]: Add read-only ssl.SSLContext.security_level attribute to retrieve the context’s security level.

bpo-41193 [https://bugs.python.org/issue?@action=redirect&bpo=41193]: The write_history() atexit function of the readline completer now ignores any OSError to ignore error if the filesystem is read-only, instead of only ignoring FileNotFoundError and PermissionError.

bpo-41182 [https://bugs.python.org/issue?@action=redirect&bpo=41182]: selector: use DefaultSelector based upon implementation

bpo-41161 [https://bugs.python.org/issue?@action=redirect&bpo=41161]: The decimal module now requires libmpdec-2.5.0. Users of –with-system-libmpdec should update their system library.

bpo-40874 [https://bugs.python.org/issue?@action=redirect&bpo=40874]: The decimal module now requires libmpdec-2.5.0.

bpo-41138 [https://bugs.python.org/issue?@action=redirect&bpo=41138]: Fixed the trace module CLI for Python source files with non-UTF-8 encoding.

bpo-31082 [https://bugs.python.org/issue?@action=redirect&bpo=31082]: Use the term “iterable” in the docstring for functools.reduce().

bpo-40521 [https://bugs.python.org/issue?@action=redirect&bpo=40521]: Remove freelist from collections.deque().

bpo-31938 [https://bugs.python.org/issue?@action=redirect&bpo=31938]: Fix default-value signatures of several functions in the select module - by Anthony Sottile.

bpo-41068 [https://bugs.python.org/issue?@action=redirect&bpo=41068]: Fixed reading files with non-ASCII names from ZIP archive directly after writing them.

bpo-41058 [https://bugs.python.org/issue?@action=redirect&bpo=41058]: pdb.find_function() now correctly determines the source file encoding.

bpo-41056 [https://bugs.python.org/issue?@action=redirect&bpo=41056]: Invalid file descriptor values are now prevented from being passed to os.fpathconf. (discovered by Coverity)

bpo-41056 [https://bugs.python.org/issue?@action=redirect&bpo=41056]: Fix a NULL pointer dereference within the ssl module during a MemoryError in the keylog callback. (discovered by Coverity)

bpo-41056 [https://bugs.python.org/issue?@action=redirect&bpo=41056]: Fixed an instance where a MemoryError within the zoneinfo module might not be reported or not reported at its source. (found by Coverity)

bpo-41048 [https://bugs.python.org/issue?@action=redirect&bpo=41048]: mimetypes.read_mime_types() function reads the rule file using UTF-8 encoding, not the locale encoding. Patch by Srinivas Reddy Thatiparthy.

bpo-41043 [https://bugs.python.org/issue?@action=redirect&bpo=41043]: Fixed the use of glob() in the stdlib: literal part of the path is now always correctly escaped.

bpo-41025 [https://bugs.python.org/issue?@action=redirect&bpo=41025]: Fixed an issue preventing the C implementation of zoneinfo.ZoneInfo from being subclassed.

bpo-35018 [https://bugs.python.org/issue?@action=redirect&bpo=35018]: Add the xml.sax.handler.LexicalHandler class that is present in other SAX XML implementations.

bpo-41002 [https://bugs.python.org/issue?@action=redirect&bpo=41002]: Improve performance of HTTPResponse.read with a given amount. Patch by Bruce Merry.

bpo-40448 [https://bugs.python.org/issue?@action=redirect&bpo=40448]: ensurepip now disables the use of pip cache when installing the bundled versions of pip and setuptools. Patch by Krzysztof Konopko.

bpo-40967 [https://bugs.python.org/issue?@action=redirect&bpo=40967]: Removed asyncio.Task.current_task() and asyncio.Task.all_tasks(). Patch contributed by Rémi Lapeyre.

bpo-40924 [https://bugs.python.org/issue?@action=redirect&bpo=40924]: Ensure importlib.resources.path returns an extant path for the SourceFileLoader’s resource reader. Avoids the regression identified in master while a long-term solution is devised.

bpo-40955 [https://bugs.python.org/issue?@action=redirect&bpo=40955]: Fix a minor memory leak in subprocess module when extra_groups was specified.

bpo-40855 [https://bugs.python.org/issue?@action=redirect&bpo=40855]: The standard deviation and variance functions in the statistics module were ignoring their mu and xbar arguments.

bpo-40939 [https://bugs.python.org/issue?@action=redirect&bpo=40939]: Use the new PEG parser when generating the stdlib keyword module.

bpo-23427 [https://bugs.python.org/issue?@action=redirect&bpo=23427]: Add sys.orig_argv attribute: the list of the original command line arguments passed to the Python executable.

bpo-33689 [https://bugs.python.org/issue?@action=redirect&bpo=33689]: Ignore empty or whitespace-only lines in .pth files. This matches the documentated behavior. Before, empty lines caused the site-packages dir to appear multiple times in sys.path. By Ido Michael, contributors Malcolm Smith and Tal Einat.

bpo-40884 [https://bugs.python.org/issue?@action=redirect&bpo=40884]: Added a defaults parameter to logging.Formatter, to allow specifying default values for custom fields. Patch by Asaf Alon and Bar Harel.

bpo-40876 [https://bugs.python.org/issue?@action=redirect&bpo=40876]: Clarify error message in the csv module.

bpo-39791 [https://bugs.python.org/issue?@action=redirect&bpo=39791]: Refresh importlib.metadata from importlib_metadata 1.6.1.

bpo-40807 [https://bugs.python.org/issue?@action=redirect&bpo=40807]: Stop codeop._maybe_compile, used by code.InteractiveInterpreter (and IDLE). from emitting each warning three times.

bpo-32604 [https://bugs.python.org/issue?@action=redirect&bpo=32604]: Fix reference leak in the select module when the module is imported in a subinterpreter.

bpo-39791 [https://bugs.python.org/issue?@action=redirect&bpo=39791]: Built-in loaders (SourceFileLoader and ZipImporter) now supply TraversableResources implementations for ResourceReader, and the fallback function has been removed.

bpo-39314 [https://bugs.python.org/issue?@action=redirect&bpo=39314]: rlcompleter.Completer and the standard Python shell now close the parenthesis for functions that take no arguments. Patch contributed by Rémi Lapeyre.

bpo-17005 [https://bugs.python.org/issue?@action=redirect&bpo=17005]: The topological sort functionality that was introduced initially in the functools module has been moved to a new graphlib module to better accommodate the new tools and keep the original scope of the functools module. Patch by Pablo Galindo

bpo-40834 [https://bugs.python.org/issue?@action=redirect&bpo=40834]: Fix truncate when sending str object with_xxsubinterpreters.channel_send.

bpo-40755 [https://bugs.python.org/issue?@action=redirect&bpo=40755]: Add rich comparisons to collections.Counter().

bpo-26407 [https://bugs.python.org/issue?@action=redirect&bpo=26407]: Unexpected errors in calling the __iter__ method are no longer masked by TypeError in csv.reader(), csv.writer.writerow() and csv.writer.writerows().

bpo-39384 [https://bugs.python.org/issue?@action=redirect&bpo=39384]: Fixed email.contentmanager to allow set_content() to set a null string.

bpo-40744 [https://bugs.python.org/issue?@action=redirect&bpo=40744]: The sqlite3 module uses SQLite API functions that require SQLite v3.7.3 or higher. This patch removes support for older SQLite versions, and explicitly requires SQLite 3.7.3 both at build, compile and runtime. Patch by Sergey Fedoseev and Erlend E. Aasland.

bpo-40777 [https://bugs.python.org/issue?@action=redirect&bpo=40777]: Initialize PyDateTime_IsoCalendarDateType.tp_base at run-time to avoid errors on some compilers.

bpo-38488 [https://bugs.python.org/issue?@action=redirect&bpo=38488]: Update ensurepip to install pip 20.1.1 and setuptools 47.1.0.

bpo-40792 [https://bugs.python.org/issue?@action=redirect&bpo=40792]: The result of operator.index() now always has exact type int. Previously, the result could have been an instance of a subclass of int.

bpo-40767 [https://bugs.python.org/issue?@action=redirect&bpo=40767]: webbrowser now properly finds the default browser in pure Wayland systems by checking the WAYLAND_DISPLAY environment variable. Patch contributed by Jérémy Attali.

bpo-40791 [https://bugs.python.org/issue?@action=redirect&bpo=40791]: hashlib.compare_digest() uses OpenSSL’s CRYPTO_memcmp() function when OpenSSL is available.

bpo-40795 [https://bugs.python.org/issue?@action=redirect&bpo=40795]: ctypes module: If ctypes fails to convert the result of a callback or if a ctypes callback function raises an exception, sys.unraisablehook is now called with an exception set. Previously, the error was logged into stderr by PyErr_Print().

bpo-16995 [https://bugs.python.org/issue?@action=redirect&bpo=16995]: Add base64.b32hexencode() and base64.b32hexdecode() to support the Base32 Encoding with Extended Hex Alphabet.

bpo-30008 [https://bugs.python.org/issue?@action=redirect&bpo=30008]: Fix ssl code to be compatible with OpenSSL 1.1.x builds that use no-deprecated and --api=1.1.0.

bpo-30064 [https://bugs.python.org/issue?@action=redirect&bpo=30064]: Fix asyncio loop.sock_* race condition issue

bpo-40759 [https://bugs.python.org/issue?@action=redirect&bpo=40759]: Deprecate the symbol module.

bpo-40756 [https://bugs.python.org/issue?@action=redirect&bpo=40756]: The second argument (extra) of LoggerAdapter.__init__ now defaults to None.

bpo-37129 [https://bugs.python.org/issue?@action=redirect&bpo=37129]: Add a new os.RWF_APPEND flag for os.pwritev().

bpo-40737 [https://bugs.python.org/issue?@action=redirect&bpo=40737]: Fix possible reference leak for sqlite3 initialization.

bpo-40726 [https://bugs.python.org/issue?@action=redirect&bpo=40726]: Handle cases where the end_lineno is None on ast.increment_lineno().

bpo-40698 [https://bugs.python.org/issue?@action=redirect&bpo=40698]: distutils upload creates SHA2-256 and Blake2b-256 digests. MD5 digests is skipped if platform blocks MD5.

bpo-40695 [https://bugs.python.org/issue?@action=redirect&bpo=40695]: hashlib no longer falls back to builtin hash implementations when OpenSSL provides a hash digest and the algorithm is blocked by security policy.

bpo-9216 [https://bugs.python.org/issue?@action=redirect&bpo=9216]: hashlib.new() passed usedforsecurity to OpenSSL EVP constructor _hashlib.new(). test_hashlib and test_smtplib handle strict security policy better.

bpo-40614 [https://bugs.python.org/issue?@action=redirect&bpo=40614]: ast.parse() will not parse self documenting expressions in f-strings when passed feature_version is less than (3, 8).

bpo-40626 [https://bugs.python.org/issue?@action=redirect&bpo=40626]: Add h5 file extension as MIME Type application/x-hdf5, as per HDF Group recommendation for HDF5 formatted data files. Patch contributed by Mark Schwab.

bpo-25920 [https://bugs.python.org/issue?@action=redirect&bpo=25920]: On macOS, when building Python for macOS 10.4 and older, which wasn’t the case for python.org macOS installer, socket.getaddrinfo() no longer uses an internal lock to prevent race conditions when calling getaddrinfo() which is thread-safe since macOS 10.5. Python 3.9 requires macOS 10.6 or newer. The internal lock caused random hang on fork when another thread was calling socket.getaddrinfo(). The lock was also used on FreeBSD older than 5.3, OpenBSD older than 201311 and NetBSD older than 4.

bpo-40671 [https://bugs.python.org/issue?@action=redirect&bpo=40671]: Prepare _hashlib for PEP 489 [https://peps.python.org/pep-0489/] and use PyModule_AddType().

bpo-32309 [https://bugs.python.org/issue?@action=redirect&bpo=32309]: Added a new coroutine asyncio.to_thread(). It is mainly used for running IO-bound functions in a separate thread to avoid blocking the event loop, and essentially works as a high-level version of run_in_executor() that can directly take keyword arguments.

bpo-36543 [https://bugs.python.org/issue?@action=redirect&bpo=36543]: Restored the deprecated xml.etree.cElementTree module.

bpo-40611 [https://bugs.python.org/issue?@action=redirect&bpo=40611]: MAP_POPULATE constant has now been added to the list of exported mmap module flags.

bpo-39881 [https://bugs.python.org/issue?@action=redirect&bpo=39881]: PEP 554 for use in the test suite. (Patch By Joannah Nanjekye)

bpo-13097 [https://bugs.python.org/issue?@action=redirect&bpo=13097]: ctypes now raises an ArgumentError when a callback is invoked with more than 1024 arguments.

bpo-39385 [https://bugs.python.org/issue?@action=redirect&bpo=39385]: A new test assertion context-manager, unittest.assertNoLogs() will ensure a given block of code emits no log messages using the logging module. Contributed by Kit Yan Choi.

bpo-23082 [https://bugs.python.org/issue?@action=redirect&bpo=23082]: Updated the error message and docs of PurePath.relative_to() to better reflect the function behaviour.

bpo-40318 [https://bugs.python.org/issue?@action=redirect&bpo=40318]: Use SQLite3 trace v2 API, if it is available.

bpo-40105 [https://bugs.python.org/issue?@action=redirect&bpo=40105]: ZipFile truncates files to avoid corruption when a shorter comment is provided in append (“a”) mode. Patch by Jan Mazur.

bpo-40084 [https://bugs.python.org/issue?@action=redirect&bpo=40084]: Fix Enum.__dir__: dir(Enum.member) now includes attributes as well as methods.

bpo-31122 [https://bugs.python.org/issue?@action=redirect&bpo=31122]: ssl.wrap_socket() now raises ssl.SSLEOFError rather than OSError when peer closes connection during TLS negotiation

bpo-39728 [https://bugs.python.org/issue?@action=redirect&bpo=39728]: fix default _missing_ so a duplicate ValueError is not set as the __context__ of the original ValueError.

bpo-39244 [https://bugs.python.org/issue?@action=redirect&bpo=39244]: Fixed multiprocessing.context.get_all_start_methods to properly return the default method first on macOS.

bpo-39040 [https://bugs.python.org/issue?@action=redirect&bpo=39040]: Fix parsing of invalid mime headers parameters by collapsing whitespace between encoded words in a bare-quote-string.

bpo-38731 [https://bugs.python.org/issue?@action=redirect&bpo=38731]: Add --quiet option to command-line interface of py_compile. Patch by Gregory Schevchenko.

bpo-35714 [https://bugs.python.org/issue?@action=redirect&bpo=35714]: struct.error is now raised if there is a null character in a struct format string.

bpo-38144 [https://bugs.python.org/issue?@action=redirect&bpo=38144]: Added the root_dir and dir_fd parameters in glob.glob().

bpo-26543 [https://bugs.python.org/issue?@action=redirect&bpo=26543]: Fix IMAP4.noop() when debug mode is enabled (ex: imaplib.Debug = 3).

bpo-12178 [https://bugs.python.org/issue?@action=redirect&bpo=12178]: csv.writer() now correctly escapes escapechar when input contains escapechar. Patch by Catalin Iacob, Berker Peksag, and Itay Elbirt.

bpo-36290 [https://bugs.python.org/issue?@action=redirect&bpo=36290]: AST nodes are now raising TypeError on conflicting keyword arguments. Patch contributed by Rémi Lapeyre.

bpo-33944 [https://bugs.python.org/issue?@action=redirect&bpo=33944]: Added site.py site-packages tracing in verbose mode.

bpo-35078 [https://bugs.python.org/issue?@action=redirect&bpo=35078]: Refactor formatweekday, formatmonthname methods in LocaleHTMLCalendar and LocaleTextCalendar classes in calendar module to call the base class methods.This enables customizable CSS classes for LocaleHTMLCalendar. Patch by Srinivas Reddy Thatiparthy

bpo-29620 [https://bugs.python.org/issue?@action=redirect&bpo=29620]: assertWarns() no longer raises a RuntimeException when accessing a module’s __warningregistry__ causes importation of a new module, or when a new module is imported in another thread. Patch by Kernc.

bpo-31844 [https://bugs.python.org/issue?@action=redirect&bpo=31844]: Remove ParserBase.error() method from the private and undocumented _markupbase module. html.parser.HTMLParser is the only subclass of ParserBase and its error() implementation was deprecated in Python 3.4 and removed in Python 3.5.

bpo-34226 [https://bugs.python.org/issue?@action=redirect&bpo=34226]: Fix cgi.parse_multipart without content_length. Patch by Roger Duran

bpo-33660 [https://bugs.python.org/issue?@action=redirect&bpo=33660]: Fix pathlib.PosixPath to resolve a relative path located on the root directory properly.

bpo-28557 [https://bugs.python.org/issue?@action=redirect&bpo=28557]: Improve the error message for a misbehaving rawio.readinto

bpo-26680 [https://bugs.python.org/issue?@action=redirect&bpo=26680]: The d.is_integer() method is added to the Decimal type, for compatibility with other number types.

bpo-26680 [https://bugs.python.org/issue?@action=redirect&bpo=26680]: The x.is_integer() method is incorporated into the abstract types of the numeric tower, Real, Rational and Integral, with appropriate default implementations.

Documentation

bpo-41428 [https://bugs.python.org/issue?@action=redirect&bpo=41428]: Add documentation for PEP 604 [https://peps.python.org/pep-0604/] (Allow writing union types as X | Y).

bpo-41774 [https://bugs.python.org/issue?@action=redirect&bpo=41774]: In Programming FAQ “Sequences (Tuples/Lists)” section, add “How do you remove multiple items from a list”.

bpo-35293 [https://bugs.python.org/issue?@action=redirect&bpo=35293]: Fix RemovedInSphinx40Warning when building the documentation. Patch by Donghee Na.

bpo-37149 [https://bugs.python.org/issue?@action=redirect&bpo=37149]: Change Shipman tkinter doc link from archive.org to TkDocs. (The doc has been removed from the NMT server.) The new link responds much faster and includes a short explanatory note.

bpo-41726 [https://bugs.python.org/issue?@action=redirect&bpo=41726]: Update the refcounts info of PyType_FromModuleAndSpec.

bpo-41624 [https://bugs.python.org/issue?@action=redirect&bpo=41624]: Fix the signature of typing.Coroutine.

bpo-40204 [https://bugs.python.org/issue?@action=redirect&bpo=40204]: Enable Sphinx 3.2 c_allow_pre_v3 option and disable c_warn_on_allowed_pre_v3 option to make the documentation compatible with Sphinx 2 and Sphinx 3.

bpo-41045 [https://bugs.python.org/issue?@action=redirect&bpo=41045]: Add documentation for debug feature of f-strings.

bpo-41314 [https://bugs.python.org/issue?@action=redirect&bpo=41314]: Changed the release when from __future__ import annotations becomes the default from 4.0 to 3.10 (following a change in PEP 563).

bpo-40979 [https://bugs.python.org/issue?@action=redirect&bpo=40979]: Refactored typing.rst, arranging more than 70 classes, functions, and decorators into new sub-sections.

bpo-40552 [https://bugs.python.org/issue?@action=redirect&bpo=40552]: Fix in tutorial section 4.2. Code snippet is now correct.

bpo-39883 [https://bugs.python.org/issue?@action=redirect&bpo=39883]: Make code, examples, and recipes in the Python documentation be licensed under the more permissive BSD0 license in addition to the existing Python 2.0 license.

bpo-37703 [https://bugs.python.org/issue?@action=redirect&bpo=37703]: Updated Documentation to comprehensively elaborate on the behaviour of gather.cancel()

Tests

bpo-41939 [https://bugs.python.org/issue?@action=redirect&bpo=41939]: Fix test_site.test_license_exists_at_url(): call urllib.request.urlcleanup() to reset the global urllib.request._opener. Patch by Victor Stinner.

bpo-41731 [https://bugs.python.org/issue?@action=redirect&bpo=41731]: Make test_cmd_line_script pass with option ‘-vv’.

bpo-41602 [https://bugs.python.org/issue?@action=redirect&bpo=41602]: Add tests for SIGINT handling in the runpy module.

bpo-41521 [https://bugs.python.org/issue?@action=redirect&bpo=41521]: test.support: Rename blacklist parameter of check__all__() to not_exported.

bpo-41477 [https://bugs.python.org/issue?@action=redirect&bpo=41477]: Make ctypes optional in test_genericalias.

bpo-41085 [https://bugs.python.org/issue?@action=redirect&bpo=41085]: Fix integer overflow in the array.array.index() method on 64-bit Windows for index larger than 2**31.

bpo-41069 [https://bugs.python.org/issue?@action=redirect&bpo=41069]: test.support.TESTFN and the current directory for tests when run via test.regrtest contain now non-ascii characters if possible.

bpo-38377 [https://bugs.python.org/issue?@action=redirect&bpo=38377]: On Linux, skip tests using multiprocessing if the current user cannot create a file in /dev/shm/ directory. Add the skip_if_broken_multiprocessing_synchronize() function to the test.support module.

bpo-41009 [https://bugs.python.org/issue?@action=redirect&bpo=41009]: Fix use of support.require_{linux|mac|freebsd}_version() decorators as class decorator.

bpo-41003 [https://bugs.python.org/issue?@action=redirect&bpo=41003]: Fix test_copyreg when numpy is installed: test.pickletester now saves/restores warnings filters when importing numpy, to ignore filters installed by numpy.

bpo-40964 [https://bugs.python.org/issue?@action=redirect&bpo=40964]: Disable remote imaplib tests, host cyrus.andrew.cmu.edu is blocking incoming connections.

bpo-40927 [https://bugs.python.org/issue?@action=redirect&bpo=40927]: Fix test_binhex when run twice: it now uses import_fresh_module() to ensure that it raises DeprecationWarning each time.

bpo-17258 [https://bugs.python.org/issue?@action=redirect&bpo=17258]: Skip some multiprocessing tests when MD5 hash digest is blocked.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Increase LOOPBACK_TIMEOUT to 10 for VxWorks RTOS.

bpo-38169 [https://bugs.python.org/issue?@action=redirect&bpo=38169]: Increase code coverage for SharedMemory and ShareableList

bpo-34401 [https://bugs.python.org/issue?@action=redirect&bpo=34401]: Make test_gdb properly run on HP-UX. Patch by Michael Osipov.

Build

bpo-38249 [https://bugs.python.org/issue?@action=redirect&bpo=38249]: Update Py_UNREACHABLE to use __builtin_unreachable() if only the compiler is able to use it. Patch by Donghee Na.

bpo-41617 [https://bugs.python.org/issue?@action=redirect&bpo=41617]: Fix pycore_bitutils.h header file to support old clang versions: __builtin_bswap16() is not available in LLVM clang 3.0.

bpo-40204 [https://bugs.python.org/issue?@action=redirect&bpo=40204]: Pin Sphinx version to 2.3.1 in Doc/Makefile.

bpo-36020 [https://bugs.python.org/issue?@action=redirect&bpo=36020]: The C99 functions snprintf() and vsnprintf() are now required to build Python.

bpo-40684 [https://bugs.python.org/issue?@action=redirect&bpo=40684]: make install now uses the PLATLIBDIR variable for the destination lib-dynload/ directory when ./configure --with-platlibdir is used.

bpo-40683 [https://bugs.python.org/issue?@action=redirect&bpo=40683]: Fixed an issue where the zoneinfo module and its tests were not included when Python is installed with make.

Windows

bpo-41744 [https://bugs.python.org/issue?@action=redirect&bpo=41744]: Fixes automatic import of props file when using the Nuget package.

bpo-41627 [https://bugs.python.org/issue?@action=redirect&bpo=41627]: The user site directory for 32-bit now includes a -32 suffix to distinguish it from the 64-bit interpreter’s directory.

bpo-41526 [https://bugs.python.org/issue?@action=redirect&bpo=41526]: Fixed layout of final page of the installer by removing the special thanks to Mark Hammond (with his permission).

bpo-41492 [https://bugs.python.org/issue?@action=redirect&bpo=41492]: Fixes the description that appears in UAC prompts.

bpo-40948 [https://bugs.python.org/issue?@action=redirect&bpo=40948]: Improve post-install message to direct people to the “py” command.

bpo-41412 [https://bugs.python.org/issue?@action=redirect&bpo=41412]: The installer will now fail to install on Windows 7 and Windows 8. Further, the UCRT dependency is now always downloaded on demand.

bpo-40741 [https://bugs.python.org/issue?@action=redirect&bpo=40741]: Update Windows release to include SQLite 3.32.3.

bpo-41142 [https://bugs.python.org/issue?@action=redirect&bpo=41142]: msilib now supports creating CAB files with non-ASCII file path and adding files with non-ASCII file path to them.

bpo-41074 [https://bugs.python.org/issue?@action=redirect&bpo=41074]: Fixed support of non-ASCII names in functions msilib.OpenDatabase() and msilib.init_database() and non-ASCII SQL in method msilib.Database.OpenView().

bpo-41039 [https://bugs.python.org/issue?@action=redirect&bpo=41039]: Stable ABI redirection DLL (python3.dll) now uses #pragma comment(linker) for re-exporting.

bpo-40164 [https://bugs.python.org/issue?@action=redirect&bpo=40164]: Updates Windows OpenSSL to 1.1.1g

bpo-39631 [https://bugs.python.org/issue?@action=redirect&bpo=39631]: Changes the registered MIME type for .py files on Windows to text/x-python instead of text/plain.

bpo-40677 [https://bugs.python.org/issue?@action=redirect&bpo=40677]: Manually define IO_REPARSE_TAG_APPEXECLINK in case some old Windows SDK doesn’t have it.

bpo-37556 [https://bugs.python.org/issue?@action=redirect&bpo=37556]: Extend py.exe help to mention overrides via venv, shebang, environmental variables & ini files.

macOS

bpo-41557 [https://bugs.python.org/issue?@action=redirect&bpo=41557]: Update macOS installer to use SQLite 3.33.0.

bpo-39580 [https://bugs.python.org/issue?@action=redirect&bpo=39580]: Avoid opening Finder window if running installer from the command line. Patch contributed by Rick Heil.

bpo-41100 [https://bugs.python.org/issue?@action=redirect&bpo=41100]: Fix configure error when building on macOS 11. Note that the current Python release was released shortly after the first developer preview of macOS 11 (Big Sur); there are other known issues with building and running on the developer preview. Big Sur is expected to be fully supported in a future bugfix release of Python 3.8.x and with 3.9.0.

bpo-40741 [https://bugs.python.org/issue?@action=redirect&bpo=40741]: Update macOS installer to use SQLite 3.32.3.

bpo-41005 [https://bugs.python.org/issue?@action=redirect&bpo=41005]: fixed an XDG settings issue not allowing macos to open browser in webbrowser.py

bpo-40741 [https://bugs.python.org/issue?@action=redirect&bpo=40741]: Update macOS installer to use SQLite 3.32.2.

IDLE

bpo-41775 [https://bugs.python.org/issue?@action=redirect&bpo=41775]: Use ‘IDLE Shell’ as shell title

bpo-35764 [https://bugs.python.org/issue?@action=redirect&bpo=35764]: Rewrite the Calltips doc section.

bpo-40181 [https://bugs.python.org/issue?@action=redirect&bpo=40181]: In calltips, stop reminding that ‘/’ marks the end of positional-only arguments.

bpo-41468 [https://bugs.python.org/issue?@action=redirect&bpo=41468]: Improve IDLE run crash error message (which users should never see).

bpo-41373 [https://bugs.python.org/issue?@action=redirect&bpo=41373]: Save files loaded with no line ending, as when blank, or different line endings, by setting its line ending to the system default. Fix regression in 3.8.4 and 3.9.0b4.

bpo-41300 [https://bugs.python.org/issue?@action=redirect&bpo=41300]: Save files with non-ascii chars. Fix regression released in 3.9.0b4 and 3.8.4.

bpo-37765 [https://bugs.python.org/issue?@action=redirect&bpo=37765]: Add keywords to module name completion list. Rewrite Completions section of IDLE doc.

bpo-41152 [https://bugs.python.org/issue?@action=redirect&bpo=41152]: The encoding of stdin, stdout and stderr in IDLE is now always UTF-8.

bpo-41144 [https://bugs.python.org/issue?@action=redirect&bpo=41144]: Make Open Module open a special module such as os.path.

bpo-39885 [https://bugs.python.org/issue?@action=redirect&bpo=39885]: Make context menu Cut and Copy work again when right-clicking within a selection.

bpo-40723 [https://bugs.python.org/issue?@action=redirect&bpo=40723]: Make test_idle pass when run after import.

C API

bpo-41936 [https://bugs.python.org/issue?@action=redirect&bpo=41936]: Removed undocumented macros Py_ALLOW_RECURSION and Py_END_ALLOW_RECURSION and the recursion_critical field of the PyInterpreterState structure.

bpo-41692 [https://bugs.python.org/issue?@action=redirect&bpo=41692]: The PyUnicode_InternImmortal() function is now deprecated and will be removed in Python 3.12: use PyUnicode_InternInPlace() instead. Patch by Victor Stinner.

bpo-41842 [https://bugs.python.org/issue?@action=redirect&bpo=41842]: Add PyCodec_Unregister() function to unregister a codec search function.

bpo-41834 [https://bugs.python.org/issue?@action=redirect&bpo=41834]: Remove the _Py_CheckRecursionLimit variable: it has been replaced by ceval.recursion_limit of the PyInterpreterState structure. Patch by Victor Stinner.

bpo-41689 [https://bugs.python.org/issue?@action=redirect&bpo=41689]: Types created with PyType_FromSpec() now make any signature in their tp_doc slot accessible from __text_signature__.

bpo-41524 [https://bugs.python.org/issue?@action=redirect&bpo=41524]: Fix bug in PyOS_mystrnicmp and PyOS_mystricmp that incremented pointers beyond the end of a string.

bpo-41324 [https://bugs.python.org/issue?@action=redirect&bpo=41324]: Add a minimal decimal capsule API. The API supports fast conversions between Decimals up to 38 digits and their triple representation as a C struct.

bpo-30155 [https://bugs.python.org/issue?@action=redirect&bpo=30155]: Add PyDateTime_DATE_GET_TZINFO() and PyDateTime_TIME_GET_TZINFO() macros for accessing the tzinfo attributes of datetime.datetime and datetime.time objects.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Revert PyType_HasFeature() change: it reads again directly the PyTypeObject.tp_flags member when the limited C API is not used, rather than always calling PyType_GetFlags() which hides implementation details.

bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123]: Remove PyUnicode_AsUnicodeCopy.

bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123]: Removed PyLong_FromUnicode().

bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123]: Removed PyUnicode_GetMax().

bpo-41123 [https://bugs.python.org/issue?@action=redirect&bpo=41123]: Removed Py_UNICODE_str* functions manipulating Py_UNICODE* strings.

bpo-41103 [https://bugs.python.org/issue?@action=redirect&bpo=41103]: PyObject_AsCharBuffer(), PyObject_AsReadBuffer(), PyObject_CheckReadBuffer(), and PyObject_AsWriteBuffer() are removed. Please migrate to new buffer protocol; PyObject_GetBuffer() and PyBuffer_Release().

bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346]: Raises DeprecationWarning for PyUnicode_FromUnicode(NULL, size) and PyUnicode_FromStringAndSize(NULL, size) with size > 0.

bpo-36346 [https://bugs.python.org/issue?@action=redirect&bpo=36346]: Mark Py_UNICODE_COPY, Py_UNICODE_FILL, PyUnicode_WSTR_LENGTH, PyUnicode_FromUnicode, PyUnicode_AsUnicode, and PyUnicode_AsUnicodeAndSize as deprecated in C. Remove Py_UNICODE_MATCH which was deprecated and broken since Python 3.3.

bpo-40989 [https://bugs.python.org/issue?@action=redirect&bpo=40989]: The PyObject_INIT() and PyObject_INIT_VAR() macros become aliases to, respectively, PyObject_Init() and PyObject_InitVar() functions.

bpo-36020 [https://bugs.python.org/issue?@action=redirect&bpo=36020]: On Windows, #include "pyerrors.h" no longer defines snprintf and vsnprintf macros.

bpo-40943 [https://bugs.python.org/issue?@action=redirect&bpo=40943]: The PY_SSIZE_T_CLEAN macro must now be defined to use PyArg_ParseTuple() and Py_BuildValue() formats which use #: es#, et#, s#, u#, y#, z#, U# and Z#. See Parsing arguments and building values and the PEP 353 [https://peps.python.org/pep-0353/].

bpo-40910 [https://bugs.python.org/issue?@action=redirect&bpo=40910]: Export explicitly the Py_GetArgcArgv() function to the C API and document the function. Previously, it was exported implicitly which no longer works since Python is built with -fvisibility=hidden.

bpo-40724 [https://bugs.python.org/issue?@action=redirect&bpo=40724]: Allow defining buffer slots in type specs.

bpo-40679 [https://bugs.python.org/issue?@action=redirect&bpo=40679]: Fix a _PyEval_EvalCode() crash if qualname argument is NULL.

bpo-40839 [https://bugs.python.org/issue?@action=redirect&bpo=40839]: Calling PyDict_GetItem() without GIL held had been allowed for historical reason. It is no longer allowed.

bpo-40826 [https://bugs.python.org/issue?@action=redirect&bpo=40826]: PyOS_InterruptOccurred() now fails with a fatal error if it is called with the GIL released.

bpo-40792 [https://bugs.python.org/issue?@action=redirect&bpo=40792]: The result of PyNumber_Index() now always has exact type int. Previously, the result could have been an instance of a subclass of int.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Convert Py_REFCNT() and Py_SIZE() macros to static inline functions. They cannot be used as l-value anymore: use Py_SET_REFCNT() and Py_SET_SIZE() to set an object reference count and size. This change is backward incompatible on purpose, to prepare the C API for an opaque PyObject structure.

bpo-40703 [https://bugs.python.org/issue?@action=redirect&bpo=40703]: The PyType_FromSpec*() functions no longer overwrite the type’s “__module__” attribute if it is set via “Py_tp_members” or “Py_tp_getset”.

bpo-39583 [https://bugs.python.org/issue?@action=redirect&bpo=39583]: Remove superfluous “extern C” declarations from Include/cpython/*.h.

Python 3.9.0 beta 1

Release date: 2020-05-19

Security

bpo-40501 [https://bugs.python.org/issue?@action=redirect&bpo=40501]: uuid no longer uses ctypes to load libuuid or rpcrt4.dll at runtime.

Core and Builtins

bpo-40663 [https://bugs.python.org/issue?@action=redirect&bpo=40663]: Correctly generate annotations where parentheses are omitted but required (e.g: Type[(str, int, *other))].

bpo-40596 [https://bugs.python.org/issue?@action=redirect&bpo=40596]: Fixed str.isidentifier() for non-canonicalized strings containing non-BMP characters on Windows.

bpo-40593 [https://bugs.python.org/issue?@action=redirect&bpo=40593]: Improved syntax errors for invalid characters in source code.

bpo-40585 [https://bugs.python.org/issue?@action=redirect&bpo=40585]: Fixed a bug when using codeop.compile_command() that was causing exceptions to be swallowed with the new parser. Patch by Pablo Galindo

bpo-40566 [https://bugs.python.org/issue?@action=redirect&bpo=40566]: Apply PEP 573 [https://peps.python.org/pep-0573/] to abc.

bpo-40502 [https://bugs.python.org/issue?@action=redirect&bpo=40502]: Initialize n->n_col_offset. (Patch by Joannah Nanjekye)

bpo-40527 [https://bugs.python.org/issue?@action=redirect&bpo=40527]: Fix command line argument parsing: no longer write errors multiple times into stderr.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port errno to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40523 [https://bugs.python.org/issue?@action=redirect&bpo=40523]: Add pass-throughs for hash() and reversed() to weakref.proxy objects. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port syslog to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40246 [https://bugs.python.org/issue?@action=redirect&bpo=40246]: Reporting a specialised error message for invalid string prefixes, which was introduced in bpo-40246 [https://bugs.python.org/issue?@action=redirect&bpo=40246], is being reverted due to backwards compatibility concerns for strings that immediately follow a reserved keyword without whitespace between them. Constructs like bg="#d00" if clear else"#fca" were failing to parse, which is not an acceptable breakage on such short notice.

bpo-40417 [https://bugs.python.org/issue?@action=redirect&bpo=40417]: Fix imp module deprecation warning when PyImport_ReloadModule is called. Patch by Robert Rouhani.

bpo-40408 [https://bugs.python.org/issue?@action=redirect&bpo=40408]: Fixed support of nested type variables in GenericAlias (e.g. list[list[T]]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _stat module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-29587 [https://bugs.python.org/issue?@action=redirect&bpo=29587]: Enable implicit exception chaining when calling generator.throw().

bpo-40328 [https://bugs.python.org/issue?@action=redirect&bpo=40328]: Add tools for generating mappings headers for CJKCodecs.

bpo-40228 [https://bugs.python.org/issue?@action=redirect&bpo=40228]: Setting frame.f_lineno is now robust w.r.t. changes in the source-to-bytecode compiler

bpo-38880 [https://bugs.python.org/issue?@action=redirect&bpo=38880]: Added the ability to list interpreters associated with channel ends in the internal subinterpreters module.

bpo-37986 [https://bugs.python.org/issue?@action=redirect&bpo=37986]: Improve performance of PyLong_FromDouble() for values that fit into long.

Library

bpo-40662 [https://bugs.python.org/issue?@action=redirect&bpo=40662]: Fixed ast.get_source_segment() for ast nodes that have incomplete location information. Patch by Irit Katriel.

bpo-40665 [https://bugs.python.org/issue?@action=redirect&bpo=40665]: Convert bisect to use Argument Clinic.

bpo-40536 [https://bugs.python.org/issue?@action=redirect&bpo=40536]: Added the available_timezones() function to the zoneinfo module. Patch by Paul Ganssle.

bpo-40645 [https://bugs.python.org/issue?@action=redirect&bpo=40645]: The hmac.HMAC exposes internal implementation details. The attributes digest_cons, inner, and outer are deprecated and will be removed in the future.

bpo-40645 [https://bugs.python.org/issue?@action=redirect&bpo=40645]: The internal module _hashlib wraps and exposes OpenSSL’s HMAC API. The new code will be used in Python 3.10 after the internal implementation details of the pure Python HMAC module are no longer part of the public API.

bpo-40637 [https://bugs.python.org/issue?@action=redirect&bpo=40637]: Builtin hash modules can now be disabled or selectively enabled with configure --with-builtin-hashlib-hashes=sha3,blake1 or --without-builtin-hashlib-hashes.

bpo-37630 [https://bugs.python.org/issue?@action=redirect&bpo=37630]: The hashlib module can now use SHA3 hashes and SHAKE XOF from OpenSSL when available.

bpo-40479 [https://bugs.python.org/issue?@action=redirect&bpo=40479]: The hashlib now compiles with OpenSSL 3.0.0-alpha2.

bpo-40257 [https://bugs.python.org/issue?@action=redirect&bpo=40257]: Revert changes to inspect.getdoc().

bpo-40607 [https://bugs.python.org/issue?@action=redirect&bpo=40607]: When cancelling a task due to timeout, asyncio.wait_for() will now propagate the exception if an error happens during cancellation. Patch by Roman Skurikhin.

bpo-40612 [https://bugs.python.org/issue?@action=redirect&bpo=40612]: Fix edge cases in SyntaxError formatting. If the offset is <= 0, no caret is printed. If the offset is > line length, the caret is printed pointing just after the last character.

bpo-40597 [https://bugs.python.org/issue?@action=redirect&bpo=40597]: If text content lines are longer than policy.max_line_length, always use a content-encoding to make sure they are wrapped.

bpo-40571 [https://bugs.python.org/issue?@action=redirect&bpo=40571]: Added functools.cache() as a simpler, more discoverable way to access the unbounded cache variant of lru_cache(maxsize=None).

bpo-40503 [https://bugs.python.org/issue?@action=redirect&bpo=40503]: PEP 615 [https://peps.python.org/pep-0615/], the zoneinfo module. Adds support for the IANA time zone database.

bpo-40397 [https://bugs.python.org/issue?@action=redirect&bpo=40397]: Removed attributes __args__ and __parameters__ from special generic aliases like typing.List (not subscripted).

bpo-40549 [https://bugs.python.org/issue?@action=redirect&bpo=40549]: Convert posixmodule.c (“posix” or “nt” module) to the multiphase initialization (PEP 489).

bpo-31033 [https://bugs.python.org/issue?@action=redirect&bpo=31033]: Add a msg argument to Future.cancel() and Task.cancel().

bpo-40541 [https://bugs.python.org/issue?@action=redirect&bpo=40541]: Added an optional counts parameter to random.sample().

bpo-40515 [https://bugs.python.org/issue?@action=redirect&bpo=40515]: The ssl and hashlib modules now actively check that OpenSSL is build with thread support. Python 3.7.0 made thread support mandatory and no longer works safely with a no-thread builds.

bpo-31033 [https://bugs.python.org/issue?@action=redirect&bpo=31033]: When a asyncio.Task is cancelled, the exception traceback now chains all the way back to where the task was first interrupted.

bpo-40504 [https://bugs.python.org/issue?@action=redirect&bpo=40504]: functools.lru_cache() objects can now be the targets of weakrefs.

bpo-40559 [https://bugs.python.org/issue?@action=redirect&bpo=40559]: Fix possible memory leak in the C implementation of asyncio.Task.

bpo-40480 [https://bugs.python.org/issue?@action=redirect&bpo=40480]: fnmatch.fnmatch() could take exponential time in the presence of multiple * pattern characters. This was repaired by generating more elaborate regular expressions to avoid futile backtracking.

bpo-40495 [https://bugs.python.org/issue?@action=redirect&bpo=40495]: compileall is now able to use hardlinks to prevent duplicates in a case when .pyc files for different optimization levels have the same content.

bpo-40457 [https://bugs.python.org/issue?@action=redirect&bpo=40457]: The ssl module now support OpenSSL builds without TLS 1.0 and 1.1 methods.

bpo-40355 [https://bugs.python.org/issue?@action=redirect&bpo=40355]: Improve error reporting in ast.literal_eval() in the presence of malformed ast.Dict nodes instead of silently ignoring any non-conforming elements. Patch by Curtis Bucher.

bpo-40465 [https://bugs.python.org/issue?@action=redirect&bpo=40465]: Deprecated the optional random argument to random.shuffle().

bpo-40459 [https://bugs.python.org/issue?@action=redirect&bpo=40459]: platform.win32_ver() now produces correct ptype strings instead of empty strings.

bpo-39435 [https://bugs.python.org/issue?@action=redirect&bpo=39435]: The first argument of pickle.loads() is now positional-only.

bpo-39305 [https://bugs.python.org/issue?@action=redirect&bpo=39305]: Update nntplib to merge nntplib.NNTP and nntplib._NNTPBase. Patch by Donghee Na.

bpo-32494 [https://bugs.python.org/issue?@action=redirect&bpo=32494]: Update dbm.gnu to use gdbm_count if possible when calling len(). Patch by Donghee Na.

bpo-40453 [https://bugs.python.org/issue?@action=redirect&bpo=40453]: Add isolated=True keyword-only parameter to _xxsubinterpreters.create(). An isolated subinterpreter cannot spawn threads, spawn a child process or call os.fork().

bpo-40286 [https://bugs.python.org/issue?@action=redirect&bpo=40286]: Remove _random.Random.randbytes(): the C implementation of randbytes(). Implement the method in Python to ease subclassing: randbytes() now directly reuses getrandbits().

bpo-40394 [https://bugs.python.org/issue?@action=redirect&bpo=40394]: Added default arguments to difflib.SequenceMatcher.find_longest_match().

bpo-39995 [https://bugs.python.org/issue?@action=redirect&bpo=39995]: Fix a race condition in concurrent.futures._ThreadWakeup: access to _ThreadWakeup is now protected with the shutdown lock.

bpo-30966 [https://bugs.python.org/issue?@action=redirect&bpo=30966]: Process.shutdown(wait=True) of concurrent.futures now closes explicitly the result queue.

bpo-30966 [https://bugs.python.org/issue?@action=redirect&bpo=30966]: Add a new close() method to the SimpleQueue class to explicitly close the queue.

bpo-39966 [https://bugs.python.org/issue?@action=redirect&bpo=39966]: Revert bpo-25597 [https://bugs.python.org/issue?@action=redirect&bpo=25597]. unittest.mock.MagicMock with wraps’ set uses default return values for magic methods.

bpo-39791 [https://bugs.python.org/issue?@action=redirect&bpo=39791]: Added files() function to importlib.resources with support for subdirectories in package data, matching backport in importlib_resources 1.5.

bpo-40375 [https://bugs.python.org/issue?@action=redirect&bpo=40375]: imaplib.IMAP4.unselect() is added. Patch by Donghee Na.

bpo-40389 [https://bugs.python.org/issue?@action=redirect&bpo=40389]: repr() now returns typing.Optional[T] when called for typing.Union of two types, one of which is NoneType.

bpo-40291 [https://bugs.python.org/issue?@action=redirect&bpo=40291]: Add support for CAN_J1939 sockets (available on Linux 5.4+)

bpo-40273 [https://bugs.python.org/issue?@action=redirect&bpo=40273]: types.MappingProxyType is now reversible.

bpo-39075 [https://bugs.python.org/issue?@action=redirect&bpo=39075]: The repr for types.SimpleNamespace is now insertion ordered rather than alphabetical.

bpo-40192 [https://bugs.python.org/issue?@action=redirect&bpo=40192]: On AIX, thread_time() is now implemented with thread_cputime() which has nanosecond resolution, rather than clock_gettime(CLOCK_THREAD_CPUTIME_ID) which has a resolution of 10 milliseconds. Patch by Batuhan Taskaya.

bpo-40025 [https://bugs.python.org/issue?@action=redirect&bpo=40025]: Raise TypeError when _generate_next_value_ is defined after members. Patch by Ethan Onstott.

bpo-39058 [https://bugs.python.org/issue?@action=redirect&bpo=39058]: In the argparse module, the repr for Namespace() and other argument holders now displayed in the order attributes were added. Formerly, it displayed in alphabetical order even though argument order is preserved the user visible parts of the module.

bpo-24416 [https://bugs.python.org/issue?@action=redirect&bpo=24416]: The isocalendar() methods of datetime.date and datetime.datetime now return a named tuple instead of a tuple.

Documentation

bpo-34790 [https://bugs.python.org/issue?@action=redirect&bpo=34790]: Add version of removal for explicit passing of coros to asyncio.wait()’s documentation

bpo-40561 [https://bugs.python.org/issue?@action=redirect&bpo=40561]: Provide docstrings for webbrowser open functions.

bpo-40499 [https://bugs.python.org/issue?@action=redirect&bpo=40499]: Mention that asyncio.wait() requires a non-empty set of awaitables.

bpo-39705 [https://bugs.python.org/issue?@action=redirect&bpo=39705]: Tutorial example for sorted() in the Loop Techniques section is given a better explanation. Also a new example is included to explain sorted()’s basic behavior.

bpo-39435 [https://bugs.python.org/issue?@action=redirect&bpo=39435]: Fix an incorrect signature for pickle.loads() in the docs

Tests

bpo-40055 [https://bugs.python.org/issue?@action=redirect&bpo=40055]: distutils.tests now saves/restores warnings filters to leave them unchanged. Importing tests imports docutils which imports pkg_resources which adds a warnings filter.

bpo-40436 [https://bugs.python.org/issue?@action=redirect&bpo=40436]: test_gdb and test.pythoninfo now check gdb command exit code.

Build

bpo-40653 [https://bugs.python.org/issue?@action=redirect&bpo=40653]: Move _dirnameW out of HAVE_SYMLINK to fix a potential compiling issue.

bpo-40514 [https://bugs.python.org/issue?@action=redirect&bpo=40514]: Add --with-experimental-isolated-subinterpreters build option to configure: better isolate subinterpreters, experimental build mode.

Windows

bpo-40650 [https://bugs.python.org/issue?@action=redirect&bpo=40650]: Include winsock2.h in pytime.c for timeval.

bpo-40458 [https://bugs.python.org/issue?@action=redirect&bpo=40458]: Increase reserved stack space to prevent overflow crash on Windows.

bpo-39148 [https://bugs.python.org/issue?@action=redirect&bpo=39148]: Add IPv6 support to asyncio datagram endpoints in ProactorEventLoop. Change the raised exception for unknown address families to ValueError as it’s not coming from Windows API.

macOS

bpo-34956 [https://bugs.python.org/issue?@action=redirect&bpo=34956]: When building Python on macOS from source, _tkinter now links with non-system Tcl and Tk frameworks if they are installed in /Library/Frameworks, as had been the case on older releases of macOS. If a macOS SDK is explicitly configured, by using --enable-universalsdk= or -isysroot, only the SDK itself is searched. The default behavior can still be overridden with --with-tcltk-includes and --with-tcltk-libs.

bpo-35569 [https://bugs.python.org/issue?@action=redirect&bpo=35569]: Expose RFC 3542 IPv6 socket options.

Tools/Demos

bpo-40479 [https://bugs.python.org/issue?@action=redirect&bpo=40479]: Update multissltest helper to test with latest OpenSSL 1.0.2, 1.1.0, 1.1.1, and 3.0.0-alpha.

bpo-40431 [https://bugs.python.org/issue?@action=redirect&bpo=40431]: Fix a syntax typo in turtledemo that now raises a SyntaxError.

bpo-40163 [https://bugs.python.org/issue?@action=redirect&bpo=40163]: Fix multissltest tool. OpenSSL has changed download URL for old releases. The multissltest tool now tries to download from current and old download URLs.

C API

bpo-39465 [https://bugs.python.org/issue?@action=redirect&bpo=39465]: Remove the _PyUnicode_ClearStaticStrings() function from the C API.

bpo-38787 [https://bugs.python.org/issue?@action=redirect&bpo=38787]: Add PyCFunction_CheckExact() macro for exact type checks now that we allow subtypes of PyCFunction, as well as PyCMethod_CheckExact() and PyCMethod_Check() for the new PyCMethod subtype.

bpo-40545 [https://bugs.python.org/issue?@action=redirect&bpo=40545]: Declare _PyErr_GetTopmostException() with PyAPI_FUNC() to properly export the function in the C API. The function remains private (_Py) prefix.

bpo-40412 [https://bugs.python.org/issue?@action=redirect&bpo=40412]: Nullify inittab_copy during finalization, preventing future interpreter initializations in an embedded situation from crashing. Patch by Gregory Szorc.

bpo-40429 [https://bugs.python.org/issue?@action=redirect&bpo=40429]: The PyThreadState_GetFrame() function now returns a strong reference to the frame.

bpo-40428 [https://bugs.python.org/issue?@action=redirect&bpo=40428]: Remove the following functions from the C API. Call PyGC_Collect() explicitly to free all free lists.

PyAsyncGen_ClearFreeLists()

PyContext_ClearFreeList()

PyDict_ClearFreeList()

PyFloat_ClearFreeList()

PyFrame_ClearFreeList()

PyList_ClearFreeList()

PySet_ClearFreeList()

PyTuple_ClearFreeList()

bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421]: New PyFrame_GetBack() function: get the frame next outer frame.

bpo-40421 [https://bugs.python.org/issue?@action=redirect&bpo=40421]: New PyFrame_GetCode() function: return a borrowed reference to the frame code.

bpo-40217 [https://bugs.python.org/issue?@action=redirect&bpo=40217]: Ensure that instances of types created with PyType_FromSpecWithBases() will visit its class object when traversing references in the garbage collector (implemented as an extension of the provided tp_traverse). Patch by Pablo Galindo.

bpo-38787 [https://bugs.python.org/issue?@action=redirect&bpo=38787]: Module C state is now accessible from C-defined heap type methods (PEP 573 [https://peps.python.org/pep-0573/]). Patch by Marcel Plch and Petr Viktorin.

Python 3.9.0 alpha 6

Release date: 2020-04-27

Security

bpo-40121 [https://bugs.python.org/issue?@action=redirect&bpo=40121]: Fixes audit events raised on creating a new socket.

bpo-39073 [https://bugs.python.org/issue?@action=redirect&bpo=39073]: Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.

bpo-39503 [https://bugs.python.org/issue?@action=redirect&bpo=39503]: CVE 2020-8492 [https://www.cve.org/CVERecord?id=CVE-2020-8492]: The AbstractBasicAuthHandler class of the urllib.request module uses an inefficient regular expression which can be exploited by an attacker to cause a denial of service. Fix the regex to prevent the catastrophic backtracking. Vulnerability reported by Ben Caller and Matt Schwager.

Core and Builtins

bpo-40313 [https://bugs.python.org/issue?@action=redirect&bpo=40313]: Improve the performance of bytes.hex().

bpo-40334 [https://bugs.python.org/issue?@action=redirect&bpo=40334]: Switch to a new parser, based on PEG. For more details see PEP 617. To temporarily switch back to the old parser, use -X oldparser or PYTHONOLDPARSER=1. In Python 3.10 we will remove the old parser completely, including the parser module (already deprecated) and anything that depends on it.

bpo-40267 [https://bugs.python.org/issue?@action=redirect&bpo=40267]: Fix the tokenizer to display the correct error message, when there is a SyntaxError on the last input character and no newline follows. It used to be unexpected EOF while parsing, while it should be invalid syntax.

bpo-39522 [https://bugs.python.org/issue?@action=redirect&bpo=39522]: Correctly unparse explicit u prefix for strings when postponed evaluation for annotations activated. Patch by Batuhan Taskaya.

bpo-40246 [https://bugs.python.org/issue?@action=redirect&bpo=40246]: Report a specialized error message, invalid string prefix, when the tokenizer encounters a string with an invalid prefix.

bpo-40082 [https://bugs.python.org/issue?@action=redirect&bpo=40082]: Fix the signal handler: it now always uses the main interpreter, rather than trying to get the current Python thread state.

bpo-37388 [https://bugs.python.org/issue?@action=redirect&bpo=37388]: str.encode() and str.decode() no longer check the encoding and errors in development mode or in debug mode during Python finalization. The codecs machinery can no longer work on very late calls to str.encode() and str.decode().

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Fix possible refleaks in _json, memo of PyScannerObject should be traversed.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to dict() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention.

bpo-40141 [https://bugs.python.org/issue?@action=redirect&bpo=40141]: Add column and line information to ast.keyword nodes. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port resource to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port math to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _uuid module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert json module to use PyType_FromSpec().

bpo-40067 [https://bugs.python.org/issue?@action=redirect&bpo=40067]: Improve the error message for multiple star expressions in an assignment. Patch by Furkan Onder

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _functools module to multiphase initialization (PEP 489). Patch by Paulo Henrique Silva.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port operator module to multiphase initialization (PEP 489). Patch by Paulo Henrique Silva.

bpo-20526 [https://bugs.python.org/issue?@action=redirect&bpo=20526]: Fix PyThreadState_Clear(). PyThreadState.frame is a borrowed reference, not a strong reference: PyThreadState_Clear() must not call Py_CLEAR(tstate->frame).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port time module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]). Patch by Paulo Henrique Silva.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _weakref extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40020 [https://bugs.python.org/issue?@action=redirect&bpo=40020]: Fix a leak and subsequent crash in parsetok.c caused by realloc misuse on a rare codepath.

bpo-39939 [https://bugs.python.org/issue?@action=redirect&bpo=39939]: Added str.removeprefix and str.removesuffix methods and corresponding bytes, bytearray, and collections.UserString methods to remove affixes from a string if present. See PEP 616 [https://peps.python.org/pep-0616/] for a full description. Patch by Dennis Sweeney.

bpo-39481 [https://bugs.python.org/issue?@action=redirect&bpo=39481]: Implement PEP 585. This supports list[int], tuple[str, …] etc.

bpo-32894 [https://bugs.python.org/issue?@action=redirect&bpo=32894]: Support unparsing of infinity numbers in postponed annotations. Patch by Batuhan Taşkaya.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to list() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Mark Shannon.

Library

bpo-40398 [https://bugs.python.org/issue?@action=redirect&bpo=40398]: typing.get_args() now always returns an empty tuple for special generic aliases.

bpo-40396 [https://bugs.python.org/issue?@action=redirect&bpo=40396]: Functions typing.get_origin(), typing.get_args() and typing.get_type_hints() support now generic aliases like list[int].

bpo-38061 [https://bugs.python.org/issue?@action=redirect&bpo=38061]: Optimize the subprocess module on FreeBSD using closefrom(). A single close(fd) syscall is cheap, but when sysconf(_SC_OPEN_MAX) is high, the loop calling close(fd) on each file descriptor can take several milliseconds.

The workaround on FreeBSD to improve performance was to load and mount the fdescfs kernel module, but this is not enabled by default.

Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans (kevans) and Kubilay Kocak (koobs): https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274

bpo-38061 [https://bugs.python.org/issue?@action=redirect&bpo=38061]: On FreeBSD, os.closerange(fd_low, fd_high) now calls closefrom(fd_low) if fd_high is greater than or equal to sysconf(_SC_OPEN_MAX).

Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans (kevans) and Kubilay Kocak (koobs): https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274

bpo-40360 [https://bugs.python.org/issue?@action=redirect&bpo=40360]: The lib2to3 module is pending deprecation due to PEP 617 [https://peps.python.org/pep-0617/].

bpo-40138 [https://bugs.python.org/issue?@action=redirect&bpo=40138]: Fix the Windows implementation of os.waitpid() for exit code larger than INT_MAX >> 8. The exit status is now interpreted as an unsigned number.

bpo-39942 [https://bugs.python.org/issue?@action=redirect&bpo=39942]: Set “__main__” as the default module name when “__name__” is missing in typing.TypeVar. Patch by Weipeng Hong.

bpo-40275 [https://bugs.python.org/issue?@action=redirect&bpo=40275]: The logging package is now imported lazily in unittest only when the assertLogs() assertion is used.

bpo-40275 [https://bugs.python.org/issue?@action=redirect&bpo=40275]: The asyncio package is now imported lazily in unittest only when the IsolatedAsyncioTestCase class is used.

bpo-40330 [https://bugs.python.org/issue?@action=redirect&bpo=40330]: In ShareableList.__setitem__(), check the size of a new string item after encoding it to utf-8, not before.

bpo-40148 [https://bugs.python.org/issue?@action=redirect&bpo=40148]: Added pathlib.Path.with_stem() to create a new Path with the stem replaced.

bpo-40325 [https://bugs.python.org/issue?@action=redirect&bpo=40325]: Deprecated support for set objects in random.sample().

bpo-40257 [https://bugs.python.org/issue?@action=redirect&bpo=40257]: Improved help for the typing module. Docstrings are now shown for all special forms and special generic aliases (like Union and List). Using help() with generic alias like List[int] will show the help for the correspondent concrete type (list in this case).

bpo-40257 [https://bugs.python.org/issue?@action=redirect&bpo=40257]: inspect.getdoc() no longer returns docstring inherited from the type of the object or from parent class if it is a class if it is not defined in the object itself. In pydoc the documentation string is now shown not only for class, function, method etc, but for any object that has its own __doc__ attribute.

bpo-40287 [https://bugs.python.org/issue?@action=redirect&bpo=40287]: Fixed SpooledTemporaryFile.seek() to return the position.

bpo-40290 [https://bugs.python.org/issue?@action=redirect&bpo=40290]: Added zscore() to statistics.NormalDist().

bpo-40282 [https://bugs.python.org/issue?@action=redirect&bpo=40282]: Allow random.getrandbits(0) to succeed and to return 0.

bpo-40286 [https://bugs.python.org/issue?@action=redirect&bpo=40286]: Add random.randbytes() function and random.Random.randbytes() method to generate random bytes.

bpo-40277 [https://bugs.python.org/issue?@action=redirect&bpo=40277]: collections.namedtuple() now provides a human-readable repr for its field accessors.

bpo-40270 [https://bugs.python.org/issue?@action=redirect&bpo=40270]: The included copy of sqlite3 on Windows is now compiled with the json extension. This allows the use of functions such as json_object.

bpo-29255 [https://bugs.python.org/issue?@action=redirect&bpo=29255]: Wait in KqueueSelector.select when no fds are registered

bpo-40260 [https://bugs.python.org/issue?@action=redirect&bpo=40260]: Ensure modulefinder uses io.open_code() and respects coding comments.

bpo-40234 [https://bugs.python.org/issue?@action=redirect&bpo=40234]: Allow again to spawn daemon threads in subinterpreters (revert change which denied them).

bpo-39207 [https://bugs.python.org/issue?@action=redirect&bpo=39207]: Workers in ProcessPoolExecutor are now spawned on demand, only when there are no available idle workers to reuse. This optimizes startup overhead and reduces the amount of lost CPU time to idle workers. Patch by Kyle Stanley.

bpo-40091 [https://bugs.python.org/issue?@action=redirect&bpo=40091]: Fix a hang at fork in the logging module: the new private _at_fork_reinit() method is now used to reinitialize locks at fork in the child process.

bpo-40149 [https://bugs.python.org/issue?@action=redirect&bpo=40149]: Implement traverse and clear slots in _abc._abc_data type.

bpo-40208 [https://bugs.python.org/issue?@action=redirect&bpo=40208]: Remove deprecated symtable.SymbolTable.has_exec().

bpo-40196 [https://bugs.python.org/issue?@action=redirect&bpo=40196]: Fix a bug in the symtable module that was causing incorrectly report global variables as local. Patch by Pablo Galindo.

bpo-40190 [https://bugs.python.org/issue?@action=redirect&bpo=40190]: Add support for _SC_AIX_REALMEM to posix.sysconf().

bpo-40182 [https://bugs.python.org/issue?@action=redirect&bpo=40182]: Removed the _field_types attribute of the typing.NamedTuple class.

bpo-36517 [https://bugs.python.org/issue?@action=redirect&bpo=36517]: Multiple inheritance with typing.NamedTuple now raises an error instead of silently ignoring other types.

bpo-40126 [https://bugs.python.org/issue?@action=redirect&bpo=40126]: Fixed reverting multiple patches in unittest.mock. Patcher’s __exit__() is now never called if its __enter__() is failed. Returning true from __exit__() silences now the exception.

bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094]: CGIHTTPRequestHandler of http.server now logs the CGI script exit code, rather than the CGI script exit status of os.waitpid(). For example, if the script is killed by signal 11, it now logs: “CGI script exit code -11.”

bpo-40108 [https://bugs.python.org/issue?@action=redirect&bpo=40108]: Improve the error message when triying to import a module using runpy and incorrectly using the “.py” extension at the end of the module name. Patch by Pablo Galindo.

bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094]: Add os.waitstatus_to_exitcode() function: convert a wait status to an exit code.

bpo-40089 [https://bugs.python.org/issue?@action=redirect&bpo=40089]: Fix threading._after_fork(): if fork was not called by a thread spawned by threading.Thread, threading._after_fork() now creates a _MainThread instance for _main_thread, instead of a _DummyThread instance.

bpo-40089 [https://bugs.python.org/issue?@action=redirect&bpo=40089]: Add a private _at_fork_reinit() method to _thread.Lock, _thread.RLock, threading.RLock and threading.Condition classes: reinitialize the lock at fork in the child process, reset the lock to the unlocked state. Rename also the private _reset_internal_locks() method of threading.Event to _at_fork_reinit().

bpo-25780 [https://bugs.python.org/issue?@action=redirect&bpo=25780]: Expose CAN_RAW_JOIN_FILTERS in the socket module.

bpo-39503 [https://bugs.python.org/issue?@action=redirect&bpo=39503]: AbstractBasicAuthHandler of urllib.request now parses all WWW-Authenticate HTTP headers and accepts multiple challenges per header: use the realm of the first Basic challenge.

bpo-39812 [https://bugs.python.org/issue?@action=redirect&bpo=39812]: Removed daemon threads from concurrent.futures by adding an internal threading._register_atexit(), which calls registered functions prior to joining all non-daemon threads. This allows for compatibility with subinterpreters, which don’t support daemon threads.

bpo-40050 [https://bugs.python.org/issue?@action=redirect&bpo=40050]: Fix importlib._bootstrap_external: avoid creating a new winreg builtin module if it’s already available in sys.modules, and remove redundant imports.

bpo-40014 [https://bugs.python.org/issue?@action=redirect&bpo=40014]: Fix os.getgrouplist(): if getgrouplist() function fails because the group list is too small, retry with a larger group list. On failure, the glibc implementation of getgrouplist() sets ngroups to the total number of groups. For other implementations, double the group list size.

bpo-40017 [https://bugs.python.org/issue?@action=redirect&bpo=40017]: Add time.CLOCK_TAI constant if the operating system support it.

bpo-40016 [https://bugs.python.org/issue?@action=redirect&bpo=40016]: In re docstring, clarify the relationship between inline and argument compile flags.

bpo-39953 [https://bugs.python.org/issue?@action=redirect&bpo=39953]: Update internal table of OpenSSL error codes in the ssl module.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: Added PEP 584 [https://peps.python.org/pep-0584/] operators to weakref.WeakValueDictionary.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: Added PEP 584 [https://peps.python.org/pep-0584/] operators to weakref.WeakKeyDictionary.

bpo-38891 [https://bugs.python.org/issue?@action=redirect&bpo=38891]: Fix linear runtime behaviour of the __getitem__ and __setitem__ methods in multiprocessing.shared_memory.ShareableList. This avoids quadratic performance when iterating a ShareableList. Patch by Thomas Krennwallner.

bpo-39682 [https://bugs.python.org/issue?@action=redirect&bpo=39682]: Remove undocumented support for closing a pathlib.Path object via its context manager. The context manager magic methods remain, but they are now a no-op, making Path objects immutable.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: Added PEP 584 [https://peps.python.org/pep-0584/] operators (| and |=) to collections.ChainMap.

bpo-39011 [https://bugs.python.org/issue?@action=redirect&bpo=39011]: Normalization of line endings in ElementTree attributes was removed, as line endings which were replaced by entity numbers should be preserved in original form.

bpo-38410 [https://bugs.python.org/issue?@action=redirect&bpo=38410]: Properly handle sys.audit() failures in sys.set_asyncgen_hooks().

bpo-36541 [https://bugs.python.org/issue?@action=redirect&bpo=36541]: lib2to3 now recognizes named assignment expressions (the walrus operator, :=)

bpo-35967 [https://bugs.python.org/issue?@action=redirect&bpo=35967]: In platform, delay the invocation of ‘uname -p’ until the processor attribute is requested.

bpo-35113 [https://bugs.python.org/issue?@action=redirect&bpo=35113]: inspect.getsource() now returns correct source code for inner class with same name as module level class. Decorators are also returned as part of source of the class. Patch by Karthikeyan Singaravelan.

bpo-33262 [https://bugs.python.org/issue?@action=redirect&bpo=33262]: Deprecate passing None as an argument for shlex.split()’s s parameter. Patch by Zackery Spytz.

bpo-31758 [https://bugs.python.org/issue?@action=redirect&bpo=31758]: Prevent crashes when using an uninitialized _elementtree.XMLParser object. Patch by Oren Milman.

Documentation

bpo-27635 [https://bugs.python.org/issue?@action=redirect&bpo=27635]: The pickle documentation incorrectly claimed that __new__ isn’t called by default when unpickling.

bpo-39879 [https://bugs.python.org/issue?@action=redirect&bpo=39879]: Updated 데이터 모델 docs to include dict() insertion order preservation. Patch by Furkan Onder and Samy Lahfa.

bpo-38387 [https://bugs.python.org/issue?@action=redirect&bpo=38387]: Document PyDoc_STRVAR macro in the C-API reference.

bpo-13743 [https://bugs.python.org/issue?@action=redirect&bpo=13743]: Some methods within xml.dom.minidom.Element class are now better documented.

Tests

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Set expected default encoding in test_c_locale_coercion.py for VxWorks RTOS.

bpo-40162 [https://bugs.python.org/issue?@action=redirect&bpo=40162]: Update Travis CI configuration to OpenSSL 1.1.1f.

bpo-40146 [https://bugs.python.org/issue?@action=redirect&bpo=40146]: Update OpenSSL to 1.1.1f in Azure Pipelines.

bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094]: Add test.support.wait_process() function.

bpo-40003 [https://bugs.python.org/issue?@action=redirect&bpo=40003]: test.bisect_cmd now copies Python command line options like -O or -W. Moreover, emit a warning if test.bisect_cmd is used with -w/--verbose2 option.

bpo-39380 [https://bugs.python.org/issue?@action=redirect&bpo=39380]: Add the encoding in ftplib.FTP and ftplib.FTP_TLS to the constructor as keyword-only and change the default from latin-1 to utf-8 to follow RFC 2640 [https://datatracker.ietf.org/doc/html/rfc2640.html].

bpo-39793 [https://bugs.python.org/issue?@action=redirect&bpo=39793]: Use the same domain when testing make_msgid. Patch by Batuhan Taskaya.

bpo-1812 [https://bugs.python.org/issue?@action=redirect&bpo=1812]: Fix newline handling in doctest.testfile when loading from a package whose loader has a get_data method. Patch by Peter Donis.

Build

bpo-38360 [https://bugs.python.org/issue?@action=redirect&bpo=38360]: Support single-argument form of macOS -isysroot flag.

bpo-40158 [https://bugs.python.org/issue?@action=redirect&bpo=40158]: Fix CPython MSBuild Properties in NuGet Package (build/native/python.props)

bpo-38527 [https://bugs.python.org/issue?@action=redirect&bpo=38527]: Fix configure check on Solaris for “float word ordering”: sometimes, the correct “grep” command was not being used. Patch by Arnon Yaari.

Windows

bpo-40164 [https://bugs.python.org/issue?@action=redirect&bpo=40164]: Updates Windows to OpenSSL 1.1.1f

bpo-8901 [https://bugs.python.org/issue?@action=redirect&bpo=8901]: Ignore the Windows registry when the -E option is used.

macOS

bpo-38329 [https://bugs.python.org/issue?@action=redirect&bpo=38329]: python.org macOS installers now update the Current version symlink of /Library/Frameworks/Python.framework/Versions for 3.9 installs. Previously, Current was only updated for Python 2.x installs. This should make it easier to embed Python 3 into other macOS applications.

bpo-40164 [https://bugs.python.org/issue?@action=redirect&bpo=40164]: Update macOS installer builds to use OpenSSL 1.1.1g.

IDLE

bpo-38439 [https://bugs.python.org/issue?@action=redirect&bpo=38439]: Add a 256×256 pixel IDLE icon to support more modern environments. Created by Andrew Clover. Delete the unused macOS idle.icns icon file.

bpo-38689 [https://bugs.python.org/issue?@action=redirect&bpo=38689]: IDLE will no longer freeze when inspect.signature fails when fetching a calltip.

Tools/Demos

bpo-40385 [https://bugs.python.org/issue?@action=redirect&bpo=40385]: Removed the checkpyc.py tool. Please see compileall without force mode as a potential alternative.

bpo-40179 [https://bugs.python.org/issue?@action=redirect&bpo=40179]: Fixed translation of #elif in Argument Clinic.

bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094]: Fix which.py script exit code: it now uses os.waitstatus_to_exitcode() to convert os.system() exit status into an exit code.

C API

bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241]: Move the PyGC_Head structure to the internal C API.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert PyObject_IS_GC() macro to a function to hide implementation details.

bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241]: Add the functions PyObject_GC_IsTracked() and PyObject_GC_IsFinalized() to the public API to allow to query if Python objects are being currently tracked or have been already finalized by the garbage collector respectively. Patch by Pablo Galindo.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: The PyObject_NEW() macro becomes an alias to the PyObject_New() macro, and the PyObject_NEW_VAR() macro becomes an alias to the PyObject_NewVar() macro, to hide implementation details. They no longer access directly the PyTypeObject.tp_basicsize member.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: PyType_HasFeature() now always calls PyType_GetFlags() to hide implementation details. Previously, it accessed directly the PyTypeObject.tp_flags member when the limited C API was not used.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert the PyObject_GET_WEAKREFS_LISTPTR() macro to a function to hide implementation details: the macro accessed directly to the PyTypeObject.tp_weaklistoffset member.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert PyObject_CheckBuffer() macro to a function to hide implementation details: the macro accessed directly the PyTypeObject.tp_as_buffer member.

bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Always declare PyIndex_Check() as an opaque function to hide implementation details: remove PyIndex_Check() macro. The macro accessed directly the PyTypeObject.tp_as_number member.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetID() function: get the unique identifier of a Python thread state.

Python 3.9.0 alpha 5

Release date: 2020-03-23

Security

bpo-38576 [https://bugs.python.org/issue?@action=redirect&bpo=38576]: Disallow control characters in hostnames in http.client, addressing CVE 2019-18348 [https://www.cve.org/CVERecord?id=CVE-2019-18348]. Such potentially malicious header injection URLs now cause a InvalidURL to be raised.

Core and Builtins

bpo-40010 [https://bugs.python.org/issue?@action=redirect&bpo=40010]: Optimize pending calls in multithreaded applications. If a thread different than the main thread schedules a pending call (Py_AddPendingCall()), the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending calls which cannot be executed. Only the main thread can execute pending calls.

Previously, the bytecode evaluation loop was interrupted at each instruction until the main thread executes pending calls.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _weakref extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _collections module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-40010 [https://bugs.python.org/issue?@action=redirect&bpo=40010]: Optimize signal handling in multithreaded applications. If a thread different than the main thread gets a signal, the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending signals which cannot be handled. Only the main thread of the main interpreter can handle signals.

Previously, the bytecode evaluation loop was interrupted at each instruction until the main thread handles signals.

bpo-39984 [https://bugs.python.org/issue?@action=redirect&bpo=39984]: If Py_AddPendingCall() is called in a subinterpreter, the function is now scheduled to be called from the subinterpreter, rather than being called from the main interpreter. Each subinterpreter now has its own list of scheduled calls.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _heapq module to multiphase initialization.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port itertools module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to frozenset() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-39984 [https://bugs.python.org/issue?@action=redirect&bpo=39984]: subinterpreters: Move _PyRuntimeState.ceval.tracing_possible to PyInterpreterState.ceval.tracing_possible: each interpreter now has its own variable.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to set() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _statistics module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39968 [https://bugs.python.org/issue?@action=redirect&bpo=39968]: Use inline function to replace extension modules’ get_module_state macros.

bpo-39965 [https://bugs.python.org/issue?@action=redirect&bpo=39965]: Correctly raise SyntaxError if await is used inside non-async functions and PyCF_ALLOW_TOP_LEVEL_AWAIT is set (like in the asyncio REPL). Patch by Pablo Galindo.

bpo-39562 [https://bugs.python.org/issue?@action=redirect&bpo=39562]: Allow executing asynchronous comprehensions on the top level when the PyCF_ALLOW_TOP_LEVEL_AWAIT flag is given. Patch by Batuhan Taskaya.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to tuple() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

bpo-38373 [https://bugs.python.org/issue?@action=redirect&bpo=38373]: Changed list overallocation strategy. It no longer overallocates if the new size is closer to overallocated size than to the old size and adds padding.

bpo-39926 [https://bugs.python.org/issue?@action=redirect&bpo=39926]: Update Unicode database to Unicode version 13.0.0.

bpo-19466 [https://bugs.python.org/issue?@action=redirect&bpo=19466]: Clear the frames of daemon threads earlier during the Python shutdown to call objects destructors. So “unclosed file” resource warnings are now emitted for daemon threads in a more reliable way.

bpo-38894 [https://bugs.python.org/issue?@action=redirect&bpo=38894]: Fix a bug that was causing incomplete results when calling pathlib.Path.glob in the presence of symlinks that point to files where the user does not have read access. Patch by Pablo Galindo and Matt Wozniski.

bpo-39877 [https://bugs.python.org/issue?@action=redirect&bpo=39877]: Fix PyEval_RestoreThread() random crash at exit with daemon threads. It now accesses the _PyRuntime variable directly instead of using tstate->interp->runtime, since tstate can be a dangling pointer after Py_Finalize() has been called. Moreover, the daemon thread now exits before trying to take the GIL.

bpo-39871 [https://bugs.python.org/issue?@action=redirect&bpo=39871]: Fix a possible SystemError in math.{atan2,copysign,remainder}() when the first argument cannot be converted to a float. Patch by Zackery Spytz.

bpo-39776 [https://bugs.python.org/issue?@action=redirect&bpo=39776]: Fix race condition where threads created by PyGILState_Ensure() could get a duplicate id.

This affects consumers of tstate->id like the contextvar caching machinery, which could return invalid cached objects under heavy thread load (observed in embedded scenarios).

bpo-39778 [https://bugs.python.org/issue?@action=redirect&bpo=39778]: Fixed a crash due to incorrect handling of weak references in collections.OrderedDict classes. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port audioop extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39702 [https://bugs.python.org/issue?@action=redirect&bpo=39702]: Relax decorator grammar restrictions to allow any valid expression (PEP 614 [https://peps.python.org/pep-0614/]).

bpo-38091 [https://bugs.python.org/issue?@action=redirect&bpo=38091]: Tweak import deadlock detection code to not deadlock itself.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _locale extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39087 [https://bugs.python.org/issue?@action=redirect&bpo=39087]: Optimize PyUnicode_AsUTF8() and PyUnicode_AsUTF8AndSize() slightly when they need to create internal UTF-8 cache.

bpo-39520 [https://bugs.python.org/issue?@action=redirect&bpo=39520]: Fix unparsing of ext slices with no items (foo[:,]). Patch by Batuhan Taskaya.

bpo-39220 [https://bugs.python.org/issue?@action=redirect&bpo=39220]: Do not optimize annotations if ‘from __future__ import annotations’ is used. Patch by Pablo Galindo.

bpo-35712 [https://bugs.python.org/issue?@action=redirect&bpo=35712]: Using NotImplemented in a boolean context has been deprecated. Patch contributed by Josh Rosenberg.

bpo-22490 [https://bugs.python.org/issue?@action=redirect&bpo=22490]: Don’t leak environment variable __PYVENV_LAUNCHER__ into the interpreter session on macOS.

Library

bpo-39830 [https://bugs.python.org/issue?@action=redirect&bpo=39830]: Add zipfile.Path to __all__ in the zipfile module.

bpo-40000 [https://bugs.python.org/issue?@action=redirect&bpo=40000]: Improved error messages for validation of ast.Constant nodes. Patch by Batuhan Taskaya.

bpo-39999 [https://bugs.python.org/issue?@action=redirect&bpo=39999]: __module__ of the AST node classes is now set to “ast” instead of “_ast”. Added docstrings for dummy AST node classes and deprecated attributes.

bpo-39991 [https://bugs.python.org/issue?@action=redirect&bpo=39991]: uuid.getnode() now skips IPv6 addresses with the same string length than a MAC address (17 characters): only use MAC addresses.

bpo-39988 [https://bugs.python.org/issue?@action=redirect&bpo=39988]: Deprecated ast.AugLoad and ast.AugStore node classes because they are no longer used.

bpo-39656 [https://bugs.python.org/issue?@action=redirect&bpo=39656]: Ensure bin/python3.# is always present in virtual environments on POSIX platforms - by Anthony Sottile.

bpo-39969 [https://bugs.python.org/issue?@action=redirect&bpo=39969]: Deprecated ast.Param node class because it’s no longer used. Patch by Batuhan Taskaya.

bpo-39360 [https://bugs.python.org/issue?@action=redirect&bpo=39360]: Ensure all workers exit when finalizing a multiprocessing.Pool implicitly via the module finalization handlers of multiprocessing. This fixes a deadlock situation that can be experienced when the Pool is not properly finalized via the context manager or a call to multiprocessing.Pool.terminate. Patch by Batuhan Taskaya and Pablo Galindo.

bpo-35370 [https://bugs.python.org/issue?@action=redirect&bpo=35370]: sys.settrace(), sys.setprofile() and _lsprof.Profiler.enable() now properly report PySys_Audit() error if “sys.setprofile” or “sys.settrace” audit event is denied.

bpo-39936 [https://bugs.python.org/issue?@action=redirect&bpo=39936]: AIX: Fix _aix_support module when the subprocess is not available, when building Python from scratch. It now uses new private _bootsubprocess module, rather than having two implementations depending if subprocess is available or not. So _aix_support.aix_platform() result is now the same if subprocess is available or not.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: collections.OrderedDict now implements | and |= (PEP 584 [https://peps.python.org/pep-0584/]).

bpo-39652 [https://bugs.python.org/issue?@action=redirect&bpo=39652]: The column name found in sqlite3.Cursor.description is now truncated on the first ‘[’ only if the PARSE_COLNAMES option is set.

bpo-39915 [https://bugs.python.org/issue?@action=redirect&bpo=39915]: Ensure unittest.mock.AsyncMock.await_args_list has call objects in the order of awaited arguments instead of using unittest.mock.Mock.call_args which has the last value of the call. Patch by Karthikeyan Singaravelan.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: Updated os.environ and os.environb to support PEP 584 [https://peps.python.org/pep-0584/]’s merge (|) and update (|=) operators.

bpo-38662 [https://bugs.python.org/issue?@action=redirect&bpo=38662]: The ensurepip module now invokes pip via the runpy module. Hence it is no longer tightly coupled with the internal API of the bundled pip version, allowing easier updates to a newer pip version both internally and for distributors.

bpo-38075 [https://bugs.python.org/issue?@action=redirect&bpo=38075]: Fix the random.Random.seed() method when a bool is passed as the seed.

bpo-39916 [https://bugs.python.org/issue?@action=redirect&bpo=39916]: More reliable use of os.scandir() in Path.glob(). It no longer emits a ResourceWarning when interrupted.

bpo-39850 [https://bugs.python.org/issue?@action=redirect&bpo=39850]: multiprocessing now supports abstract socket addresses (if abstract sockets are supported in the running platform). When creating arbitrary addresses (like when default-constructing multiprocessing.connection.Listener objects) abstract sockets are preferred to avoid the case when the temporary-file-generated address is too large for an AF_UNIX socket address. Patch by Pablo Galindo.

bpo-36287 [https://bugs.python.org/issue?@action=redirect&bpo=36287]: ast.dump() no longer outputs optional fields and attributes with default values. The default values for optional fields and attributes of AST nodes are now set as class attributes (e.g. Constant.kind is set to None).

bpo-39889 [https://bugs.python.org/issue?@action=redirect&bpo=39889]: Fixed ast.unparse() for extended slices containing a single element (e.g. a[i:j,]). Remove redundant tuples when index with a tuple (e.g. a[i, j]).

bpo-39828 [https://bugs.python.org/issue?@action=redirect&bpo=39828]: Fix json.tool to catch BrokenPipeError. Patch by Donghee Na.

bpo-13487 [https://bugs.python.org/issue?@action=redirect&bpo=13487]: Avoid a possible “RuntimeError: dictionary changed size during iteration” from inspect.getmodule() when it tried to loop through sys.modules.

bpo-39674 [https://bugs.python.org/issue?@action=redirect&bpo=39674]: Revert “bpo-37330 [https://bugs.python.org/issue?@action=redirect&bpo=37330]: open() no longer accept ‘U’ in file mode”. The “U” mode of open() is kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.

bpo-28577 [https://bugs.python.org/issue?@action=redirect&bpo=28577]: The hosts method on 32-bit prefix length IPv4Networks and 128-bit prefix IPv6Networks now returns a list containing the single Address instead of an empty list.

bpo-39826 [https://bugs.python.org/issue?@action=redirect&bpo=39826]: Add getConnection method to logging HTTPHandler to enable custom connections.

bpo-39763 [https://bugs.python.org/issue?@action=redirect&bpo=39763]: Reimplement distutils.spawn.spawn function with the subprocess module.

bpo-39794 [https://bugs.python.org/issue?@action=redirect&bpo=39794]: Add –without-decimal-contextvar build option. This enables a thread-local rather than a coroutine local context.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: collections.defaultdict now implements | (PEP 584 [https://peps.python.org/pep-0584/]).

bpo-39517 [https://bugs.python.org/issue?@action=redirect&bpo=39517]: Fix runpy.run_path() when using pathlike objects

bpo-39775 [https://bugs.python.org/issue?@action=redirect&bpo=39775]: Change inspect.Signature.parameters back to collections.OrderedDict. This was changed to dict in Python 3.9.0a4.

bpo-39678 [https://bugs.python.org/issue?@action=redirect&bpo=39678]: Refactor queue_manager in concurrent.futures.ProcessPoolExecutor to make it easier to maintain.

bpo-39764 [https://bugs.python.org/issue?@action=redirect&bpo=39764]: Fix AttributeError when calling get_stack on a PyAsyncGenObject Task

bpo-39769 [https://bugs.python.org/issue?@action=redirect&bpo=39769]: The compileall.compile_dir() function’s ddir parameter and the compileall command line flag -d no longer write the wrong pathname to the generated pyc file for submodules beneath the root of the directory tree being compiled. This fixes a regression introduced with Python 3.5.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: types.MappingProxyType objects now support the merge (|) operator from PEP 584 [https://peps.python.org/pep-0584/].

bpo-38691 [https://bugs.python.org/issue?@action=redirect&bpo=38691]: The importlib module now ignores the PYTHONCASEOK environment variable when the -E or -I command line options are being used.

bpo-39719 [https://bugs.python.org/issue?@action=redirect&bpo=39719]: Remove tempfile.SpooledTemporaryFile.softspace() as files no longer have the softspace attribute in Python 3. Patch by Shantanu.

bpo-39667 [https://bugs.python.org/issue?@action=redirect&bpo=39667]: Improve pathlib.Path compatibility on zipfile.Path and correct performance degradation as found in zipp 3.0.

bpo-39638 [https://bugs.python.org/issue?@action=redirect&bpo=39638]: Keep ASDL signatures in the docstrings for AST nodes. Patch by Batuhan Taskaya

bpo-39639 [https://bugs.python.org/issue?@action=redirect&bpo=39639]: Deprecated ast.Suite node class because it’s no longer used. Patch by Batuhan Taskaya.

bpo-39609 [https://bugs.python.org/issue?@action=redirect&bpo=39609]: Add thread_name_prefix to default asyncio executor

bpo-39548 [https://bugs.python.org/issue?@action=redirect&bpo=39548]: Fix handling of header in urllib.request.AbstractDigestAuthHandler when the optional qop parameter is not present.

bpo-39509 [https://bugs.python.org/issue?@action=redirect&bpo=39509]: HTTP status codes 103 EARLY_HINTS and 425 TOO_EARLY are added to http.HTTPStatus. Patch by Donghee Na.

bpo-39507 [https://bugs.python.org/issue?@action=redirect&bpo=39507]: Adding HTTP status 418 “I’m a Teapot” to HTTPStatus in http library. Patch by Ross Rhodes.

bpo-39495 [https://bugs.python.org/issue?@action=redirect&bpo=39495]: Remove default value from attrs parameter of xml.etree.ElementTree.TreeBuilder.start() for consistency between Python and C implementations.

bpo-38971 [https://bugs.python.org/issue?@action=redirect&bpo=38971]: Open issue in the BPO indicated a desire to make the implementation of codecs.open() at parity with io.open(), which implements a try/except to assure file stream gets closed before an exception is raised.

bpo-38641 [https://bugs.python.org/issue?@action=redirect&bpo=38641]: Added starred expressions support to return and yield statements for lib2to3. Patch by Vlad Emelianov.

bpo-37534 [https://bugs.python.org/issue?@action=redirect&bpo=37534]: When using minidom module to generate XML documents the ability to add Standalone Document Declaration is added. All the changes are made to generate a document in compliance with Extensible Markup Language (XML) 1.0 (Fifth Edition) W3C Recommendation (available here: https://www.w3.org/TR/xml/#sec-prolog-dtd).

bpo-34788 [https://bugs.python.org/issue?@action=redirect&bpo=34788]: Add support for scoped IPv6 addresses to ipaddress. Patch by Oleksandr Pavliuk.

bpo-34822 [https://bugs.python.org/issue?@action=redirect&bpo=34822]: Simplified AST for subscription. Simple indices are now represented by their value, extended slices are represented as tuples. ast classes Index and ExtSlice are considered deprecated and will be removed in future Python versions. In the meantime, Index(value) now returns a value itself, ExtSlice(slices) returns Tuple(slices, Load()).

Documentation

bpo-39868 [https://bugs.python.org/issue?@action=redirect&bpo=39868]: Updated the Language Reference for PEP 572 [https://peps.python.org/pep-0572/].

bpo-13790 [https://bugs.python.org/issue?@action=redirect&bpo=13790]: Change ‘string’ to ‘specification’ in format doc.

bpo-17422 [https://bugs.python.org/issue?@action=redirect&bpo=17422]: The language reference no longer restricts default class namespaces to dicts only.

bpo-39530 [https://bugs.python.org/issue?@action=redirect&bpo=39530]: Fix misleading documentation about mixed-type numeric comparisons.

bpo-39718 [https://bugs.python.org/issue?@action=redirect&bpo=39718]: Update token documentation to reflect additions in Python 3.8

bpo-39677 [https://bugs.python.org/issue?@action=redirect&bpo=39677]: Changed operand name of MAKE_FUNCTION from argc to flags for module dis

Tests

bpo-40019 [https://bugs.python.org/issue?@action=redirect&bpo=40019]: test_gdb now skips tests if it detects that gdb failed to read debug information because the Python binary is optimized.

bpo-27807 [https://bugs.python.org/issue?@action=redirect&bpo=27807]: test_site.test_startup_imports() is now skipped if a path of sys.path contains a .pth file.

bpo-26067 [https://bugs.python.org/issue?@action=redirect&bpo=26067]: Do not fail test_shutil test_chown test when uid or gid of user cannot be resolved to a name.

bpo-39855 [https://bugs.python.org/issue?@action=redirect&bpo=39855]: test_subprocess.test_user() now skips the test on an user name if the user name doesn’t exist. For example, skip the test if the user “nobody” doesn’t exist on Linux.

Build

bpo-39761 [https://bugs.python.org/issue?@action=redirect&bpo=39761]: Fix build with DTrace but without additional DFLAGS.

bpo-39763 [https://bugs.python.org/issue?@action=redirect&bpo=39763]: setup.py now uses a basic implementation of the subprocess module if the subprocess module is not available: before required C extension modules are built.

bpo-1294959 [https://bugs.python.org/issue?@action=redirect&bpo=1294959]: Add --with-platlibdir option to the configure script: name of the platform-specific library directory, stored in the new sys.platlibdir attribute. It is used to build the path of platform-specific extension modules and the path of the standard library. It is equal to "lib" on most platforms. On Fedora and SuSE, it is equal to "lib64" on 64-bit platforms. Patch by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner.

Windows

bpo-39930 [https://bugs.python.org/issue?@action=redirect&bpo=39930]: Ensures the required vcruntime140.dll is included in install packages.

bpo-39847 [https://bugs.python.org/issue?@action=redirect&bpo=39847]: Avoid hang when computer is hibernated whilst waiting for a mutex (for lock-related objects from threading) around 49-day uptime.

bpo-38597 [https://bugs.python.org/issue?@action=redirect&bpo=38597]: distutils will no longer statically link vcruntime140.dll when a redistributable version is unavailable. All future releases of CPython will include a copy of this DLL to ensure distributed extensions can continue to load.

bpo-38380 [https://bugs.python.org/issue?@action=redirect&bpo=38380]: Update Windows builds to use SQLite 3.31.1

bpo-39789 [https://bugs.python.org/issue?@action=redirect&bpo=39789]: Update Windows release build machines to Visual Studio 2019 (MSVC 14.2).

bpo-34803 [https://bugs.python.org/issue?@action=redirect&bpo=34803]: Package for nuget.org now includes repository reference and bundled icon image.

macOS

bpo-38380 [https://bugs.python.org/issue?@action=redirect&bpo=38380]: Update macOS builds to use SQLite 3.31.1

IDLE

bpo-27115 [https://bugs.python.org/issue?@action=redirect&bpo=27115]: For ‘Go to Line’, use a Query box subclass with IDLE standard behavior and improved error checking.

bpo-39885 [https://bugs.python.org/issue?@action=redirect&bpo=39885]: Since clicking to get an IDLE context menu moves the cursor, any text selection should be and now is cleared.

bpo-39852 [https://bugs.python.org/issue?@action=redirect&bpo=39852]: Edit “Go to line” now clears any selection, preventing accidental deletion. It also updates Ln and Col on the status bar.

bpo-39781 [https://bugs.python.org/issue?@action=redirect&bpo=39781]: Selecting code context lines no longer causes a jump.

Tools/Demos

bpo-36184 [https://bugs.python.org/issue?@action=redirect&bpo=36184]: Port python-gdb.py to FreeBSD. python-gdb.py now checks for “take_gil” function name to check if a frame tries to acquire the GIL, instead of checking for “pthread_cond_timedwait” which is specific to Linux and can be a different condition than the GIL.

bpo-38080 [https://bugs.python.org/issue?@action=redirect&bpo=38080]: Added support to fix getproxies in the lib2to3.fixes.fix_urllib module. Patch by José Roberto Meza Cabrera.

C API

bpo-40024 [https://bugs.python.org/issue?@action=redirect&bpo=40024]: Add PyModule_AddType() helper function: add a type to a module. Patch by Donghee Na.

bpo-39946 [https://bugs.python.org/issue?@action=redirect&bpo=39946]: Remove _PyRuntime.getframe hook and remove _PyThreadState_GetFrame macro which was an alias to _PyRuntime.getframe. They were only exposed by the internal C API. Remove also PyThreadFrameGetter type.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetFrame() function: get the current frame of a Python thread state.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Add _PyArg_NoKwnames helper function. Patch by Donghee Na.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetInterpreter(): get the interpreter of a Python thread state.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyInterpreterState_Get() function to the limited C API.

bpo-35370 [https://bugs.python.org/issue?@action=redirect&bpo=35370]: If PySys_Audit() fails in PyEval_SetProfile() or PyEval_SetTrace(), log the error as an unraisable exception.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Move the static inline function flavor of Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() to the internal C API: they access PyThreadState attributes. The limited C API provides regular functions which hide implementation details.

bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro no longer access PyThreadState attributes, but call new private _PyTrash_begin() and _PyTrash_end() functions which hide implementation details.

bpo-39884 [https://bugs.python.org/issue?@action=redirect&bpo=39884]: PyDescr_NewMethod() and PyCFunction_NewEx() now include the method name in the SystemError “bad call flags” error message to ease debug.

bpo-39877 [https://bugs.python.org/issue?@action=redirect&bpo=39877]: Deprecated PyEval_InitThreads() and PyEval_ThreadsInitialized(). Calling PyEval_InitThreads() now does nothing.

bpo-38249 [https://bugs.python.org/issue?@action=redirect&bpo=38249]: Py_UNREACHABLE is now implemented with __builtin_unreachable() and analogs in release mode.

bpo-38643 [https://bugs.python.org/issue?@action=redirect&bpo=38643]: PyNumber_ToBase() now raises a SystemError instead of crashing when called with invalid base.

bpo-39882 [https://bugs.python.org/issue?@action=redirect&bpo=39882]: The Py_FatalError() function is replaced with a macro which logs automatically the name of the current function, unless the Py_LIMITED_API macro is defined.

bpo-39824 [https://bugs.python.org/issue?@action=redirect&bpo=39824]: Extension modules: m_traverse, m_clear and m_free functions of PyModuleDef are no longer called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec function). More precisely, these functions are not called if m_size is greater than 0 and the module state (as returned by PyModule_GetState()) is NULL.

Extension modules without module state (m_size <= 0) are not affected.

bpo-38913 [https://bugs.python.org/issue?@action=redirect&bpo=38913]: Fixed segfault in Py_BuildValue() called with a format containing “#” and undefined PY_SSIZE_T_CLEAN whwn an exception is set.

bpo-38500 [https://bugs.python.org/issue?@action=redirect&bpo=38500]: Add a private API to get and set the frame evaluation function: add _PyInterpreterState_GetEvalFrameFunc() and _PyInterpreterState_SetEvalFrameFunc() C functions. The _PyFrameEvalFunction function type now takes a tstate parameter.

Python 3.9.0 alpha 4

Release date: 2020-02-25

Security

bpo-39184 [https://bugs.python.org/issue?@action=redirect&bpo=39184]: Add audit events to functions in fcntl, msvcrt, os, resource, shutil, signal and syslog.

bpo-39401 [https://bugs.python.org/issue?@action=redirect&bpo=39401]: Avoid unsafe DLL load at startup on Windows 7 and earlier.

bpo-39184 [https://bugs.python.org/issue?@action=redirect&bpo=39184]: Add audit events to command execution functions in os and pty modules.

Core and Builtins

bpo-39382 [https://bugs.python.org/issue?@action=redirect&bpo=39382]: Fix a use-after-free in the single inheritance path of issubclass(), when the __bases__ of an object has a single reference, and so does its first item. Patch by Yonatan Goldschmidt.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Update clinic tool to use Py_IS_TYPE(). Patch by Donghee Na.

bpo-39619 [https://bugs.python.org/issue?@action=redirect&bpo=39619]: Enable use of os.chroot() on HP-UX systems.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_IS_TYPE() static inline function to check whether the object o type is type.

bpo-39606 [https://bugs.python.org/issue?@action=redirect&bpo=39606]: Fix regression caused by fix for bpo-39386 [https://bugs.python.org/issue?@action=redirect&bpo=39386], that prevented calling aclose on an async generator that had already been closed or exhausted.

bpo-39579 [https://bugs.python.org/issue?@action=redirect&bpo=39579]: Change the ending column offset of Attribute nodes constructed in ast_for_dotted_name to point at the end of the current node and not at the end of the last NAME node.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _crypt extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _contextvars extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39510 [https://bugs.python.org/issue?@action=redirect&bpo=39510]: Fix segfault in readinto() method on closed BufferedReader.

bpo-39502 [https://bugs.python.org/issue?@action=redirect&bpo=39502]: Fix time.localtime() on 64-bit AIX to support years before 1902 and after 2038. Patch by M Felt.

bpo-39492 [https://bugs.python.org/issue?@action=redirect&bpo=39492]: Fix a reference cycle in the C Pickler that was preventing the garbage collection of deleted, pickled objects.

bpo-39453 [https://bugs.python.org/issue?@action=redirect&bpo=39453]: Fixed a possible crash in list.__contains__() when a list is changed during comparing items. Patch by Donghee Na.

bpo-39434 [https://bugs.python.org/issue?@action=redirect&bpo=39434]: floor division of float operation now has a better performance. Also the message of ZeroDivisionError for this operation is updated. Patch by Donghee Na.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _codecs extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _bz2 extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _abc extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39320 [https://bugs.python.org/issue?@action=redirect&bpo=39320]: Replace two complex bytecodes for building dicts with two simpler ones. The new bytecodes DICT_MERGE and DICT_UPDATE have been added The old bytecodes BUILD_MAP_UNPACK and BUILD_MAP_UNPACK_WITH_CALL have been removed.

bpo-39219 [https://bugs.python.org/issue?@action=redirect&bpo=39219]: Syntax errors raised in the tokenizer now always set correct “text” and “offset” attributes.

bpo-36051 [https://bugs.python.org/issue?@action=redirect&bpo=36051]: Drop the GIL during large bytes.join operations. Patch by Bruce Merry.

bpo-38960 [https://bugs.python.org/issue?@action=redirect&bpo=38960]: Fix DTrace build issues on FreeBSD. Patch by David Carlier.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to range() by about 30%, by using the PEP 590 vectorcall calling convention. Patch by Mark Shannon.

bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: dict (and collections.UserDict) objects now support PEP 584’s merge (|) and update (|=) operators. Patch by Brandt Bucher.

bpo-32856 [https://bugs.python.org/issue?@action=redirect&bpo=32856]: Optimized the idiom for assignment a temporary variable in comprehensions. Now for y in [expr] in comprehensions is as fast as a simple assignment y = expr.

Library

bpo-30566 [https://bugs.python.org/issue?@action=redirect&bpo=30566]: Fix IndexError when trying to decode an invalid string with punycode codec.

bpo-39649 [https://bugs.python.org/issue?@action=redirect&bpo=39649]: Remove obsolete check for __args__ in bdb.Bdb.format_stack_entry.

bpo-39648 [https://bugs.python.org/issue?@action=redirect&bpo=39648]: Expanded math.gcd() and math.lcm() to handle multiple arguments.

bpo-39681 [https://bugs.python.org/issue?@action=redirect&bpo=39681]: Fix a regression where the C pickle module wouldn’t allow unpickling from a file-like object that doesn’t expose a readinto() method.

bpo-35950 [https://bugs.python.org/issue?@action=redirect&bpo=35950]: Raise io.UnsupportedOperation in io.BufferedReader.truncate() when it is called on a read-only io.BufferedReader instance.

bpo-39479 [https://bugs.python.org/issue?@action=redirect&bpo=39479]: Add math.lcm() function: least common multiple.

bpo-39674 [https://bugs.python.org/issue?@action=redirect&bpo=39674]: Revert “Do not expose abstract collection classes in the collections module” change (bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988]). Aliases to ABC like collections.Mapping are kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.

bpo-39104 [https://bugs.python.org/issue?@action=redirect&bpo=39104]: Fix hanging ProcessPoolExcutor on shutdown(wait=False) when a task has failed pickling.

bpo-39627 [https://bugs.python.org/issue?@action=redirect&bpo=39627]: Fixed TypedDict totality check for inherited keys.

bpo-39474 [https://bugs.python.org/issue?@action=redirect&bpo=39474]: Fixed starting position of AST for expressions like (a)(b), (a)[b] and (a).b.

bpo-21016 [https://bugs.python.org/issue?@action=redirect&bpo=21016]: The pydoc and trace modules now use the sysconfig module to get the path to the Python standard library, to support uncommon installation path like /usr/lib64/python3.9/ on Fedora. Patch by Jan Matějek.

bpo-39590 [https://bugs.python.org/issue?@action=redirect&bpo=39590]: Collections.deque now holds strong references during deque.__contains__ and deque.count, fixing crashes.

bpo-39586 [https://bugs.python.org/issue?@action=redirect&bpo=39586]: The distutils bdist_msi command is deprecated in Python 3.9, use bdist_wheel (wheel packages) instead.

bpo-39595 [https://bugs.python.org/issue?@action=redirect&bpo=39595]: Improved performance of zipfile.Path for files with a large number of entries. Also improved performance and fixed minor issue as published with importlib_metadata 1.5 [https://importlib-metadata.readthedocs.io/en/latest/history.html#v1-5-0].

bpo-39350 [https://bugs.python.org/issue?@action=redirect&bpo=39350]: Fix regression in fractions.Fraction if the numerator and/or the denominator is an int subclass. The math.gcd() function is now used to normalize the numerator and denominator. math.gcd() always return a int type. Previously, the GCD type depended on numerator and denominator.

bpo-39567 [https://bugs.python.org/issue?@action=redirect&bpo=39567]: Added audit for os.walk(), os.fwalk(), pathlib.Path.glob() and pathlib.Path.rglob().

bpo-39559 [https://bugs.python.org/issue?@action=redirect&bpo=39559]: Remove unused, undocumented argument getters from uuid.getnode()

bpo-38149 [https://bugs.python.org/issue?@action=redirect&bpo=38149]: sys.audit() is now called only once per call of glob.glob() and glob.iglob().

bpo-39546 [https://bugs.python.org/issue?@action=redirect&bpo=39546]: Fix a regression in ArgumentParser where allow_abbrev=False was ignored for long options that used a prefix character other than “-“.

bpo-39450 [https://bugs.python.org/issue?@action=redirect&bpo=39450]: Striped whitespace from docstring before returning it from unittest.case.shortDescription().

bpo-12915 [https://bugs.python.org/issue?@action=redirect&bpo=12915]: A new function resolve_name has been added to the pkgutil module. This resolves a string of the form 'a.b.c.d' or 'a.b:c.d' to an object. In the example, a.b is a package/module and c.d is an object within that package/module reached via recursive attribute access.

bpo-39353 [https://bugs.python.org/issue?@action=redirect&bpo=39353]: The binascii.crc_hqx() function is no longer deprecated.

bpo-39493 [https://bugs.python.org/issue?@action=redirect&bpo=39493]: Mark typing.IO.closed as a property

bpo-39491 [https://bugs.python.org/issue?@action=redirect&bpo=39491]: Add typing.Annotated and include_extras parameter to typing.get_type_hints() as part of PEP 593 [https://peps.python.org/pep-0593/]. Patch by Till Varoquaux, documentation by Till Varoquaux and Konstantin Kashin.

bpo-39485 [https://bugs.python.org/issue?@action=redirect&bpo=39485]: Fix a bug in unittest.mock.create_autospec() that would complain about the wrong number of arguments for custom descriptors defined in an extension module returning functions.

bpo-38932 [https://bugs.python.org/issue?@action=redirect&bpo=38932]: Mock fully resets child objects on reset_mock(). Patch by Vegard Stikbakke

bpo-39082 [https://bugs.python.org/issue?@action=redirect&bpo=39082]: Allow AsyncMock to correctly patch static/class methods

bpo-39432 [https://bugs.python.org/issue?@action=redirect&bpo=39432]: Implement PEP-489 algorithm for non-ascii “PyInit_…” symbol names in distutils to make it export the correct init symbol also on Windows.

bpo-18819 [https://bugs.python.org/issue?@action=redirect&bpo=18819]: Omit devmajor and devminor fields for non-device files in tarfile archives, enabling bit-for-bit compatibility with GNU tar(1).

bpo-39349 [https://bugs.python.org/issue?@action=redirect&bpo=39349]: Added a new cancel_futures parameter to concurrent.futures.Executor.shutdown() that cancels all pending futures which have not started running, instead of waiting for them to complete before shutting down the executor.

bpo-39274 [https://bugs.python.org/issue?@action=redirect&bpo=39274]: bool(fraction.Fraction) now returns a boolean even if (numerator != 0) does not return a boolean (ex: numpy number).

bpo-34793 [https://bugs.python.org/issue?@action=redirect&bpo=34793]: Remove support for with (await asyncio.lock): and with (yield from asyncio.lock):. The same is correct for asyncio.Condition and asyncio.Semaphore.

bpo-25597 [https://bugs.python.org/issue?@action=redirect&bpo=25597]: Ensure, if wraps is supplied to unittest.mock.MagicMock, it is used to calculate return values for the magic methods instead of using the default return values. Patch by Karthikeyan Singaravelan.

bpo-36350 [https://bugs.python.org/issue?@action=redirect&bpo=36350]: inspect.Signature.parameters and inspect.BoundArguments.arguments are now dicts instead of OrderedDicts. Patch contributed by Rémi Lapeyre.

bpo-35727 [https://bugs.python.org/issue?@action=redirect&bpo=35727]: Fix sys.exit() and sys.exit(None) exit code propagation when used in multiprocessing.Process.

bpo-32173 [https://bugs.python.org/issue?@action=redirect&bpo=32173]: * Add lazycache function to __all__. * Use dict.clear to clear the cache. * Refactoring getline function and checkcache function.

Documentation

bpo-17422 [https://bugs.python.org/issue?@action=redirect&bpo=17422]: The language reference now specifies restrictions on class namespaces. Adapted from a patch by Ethan Furman.

bpo-39572 [https://bugs.python.org/issue?@action=redirect&bpo=39572]: Updated documentation of total flag of TypedDict.

bpo-39654 [https://bugs.python.org/issue?@action=redirect&bpo=39654]: In pyclbr doc, update ‘class’ to ‘module’ where appropriate and add readmodule comment. Patch by Hakan Çelik.

bpo-39153 [https://bugs.python.org/issue?@action=redirect&bpo=39153]: Clarify refcounting semantics for the following functions: - PyObject_SetItem - PyMapping_SetItemString - PyDict_SetItem - PyDict_SetItemString

bpo-39392 [https://bugs.python.org/issue?@action=redirect&bpo=39392]: Explain that when filling with turtle, overlap regions may be left unfilled.

bpo-39369 [https://bugs.python.org/issue?@action=redirect&bpo=39369]: Update mmap readline method description. The fact that the readline method does update the file position should not be ignored since this might give the impression for the programmer that it doesn’t update it.

bpo-9056 [https://bugs.python.org/issue?@action=redirect&bpo=9056]: Include subsection in TOC for PDF version of docs.

Tests

bpo-38325 [https://bugs.python.org/issue?@action=redirect&bpo=38325]: Skip tests on non-BMP characters of test_winconsoleio.

bpo-39502 [https://bugs.python.org/issue?@action=redirect&bpo=39502]: Skip test_zipfile.test_add_file_after_2107() if time.localtime() fails with OverflowError. It is the case on AIX 6.1 for example.

Build

bpo-39489 [https://bugs.python.org/issue?@action=redirect&bpo=39489]: Remove COUNT_ALLOCS special build.

Windows

bpo-39553 [https://bugs.python.org/issue?@action=redirect&bpo=39553]: Delete unused code related to SxS manifests.

bpo-39439 [https://bugs.python.org/issue?@action=redirect&bpo=39439]: Honor the Python path when a virtualenv is active on Windows.

bpo-39393 [https://bugs.python.org/issue?@action=redirect&bpo=39393]: Improve the error message when attempting to load a DLL with unresolved dependencies.

bpo-38883 [https://bugs.python.org/issue?@action=redirect&bpo=38883]: home() and expanduser() on Windows now prefer USERPROFILE and no longer use HOME, which is not normally set for regular user accounts. This makes them again behave like os.path.expanduser(), which was changed to ignore HOME in 3.8, see bpo-36264 [https://bugs.python.org/issue?@action=redirect&bpo=36264].

bpo-39185 [https://bugs.python.org/issue?@action=redirect&bpo=39185]: The build.bat script has additional options for very-quiet output (-q) and very-verbose output (-vv)

IDLE

bpo-39663 [https://bugs.python.org/issue?@action=redirect&bpo=39663]: Add tests for pyparse find_good_parse_start().

bpo-39600 [https://bugs.python.org/issue?@action=redirect&bpo=39600]: In the font configuration window, remove duplicated font names.

bpo-30780 [https://bugs.python.org/issue?@action=redirect&bpo=30780]: Add remaining configdialog tests for buttons and highlights and keys tabs.

bpo-39388 [https://bugs.python.org/issue?@action=redirect&bpo=39388]: IDLE Settings Cancel button now cancels pending changes

bpo-38792 [https://bugs.python.org/issue?@action=redirect&bpo=38792]: Close an IDLE shell calltip if a KeyboardInterrupt or shell restart occurs. Patch by Zackery Spytz.

C API

bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Move the bytes_methods.h header file to the internal C API as pycore_bytes_methods.h: it only contains private symbols (prefixed by _Py), except of the PyDoc_STRVAR_shared() macro.

bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Move the dtoa.h header file to the internal C API as pycore_dtoa.h: it only contains private functions (prefixed by _Py). The math and cmath modules must now be compiled with the Py_BUILD_CORE macro defined.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_SET_SIZE() function to set the size of an object.

bpo-39500 [https://bugs.python.org/issue?@action=redirect&bpo=39500]: PyUnicode_IsIdentifier() does not call Py_FatalError() anymore if the string is not ready.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_SET_TYPE() function to set the type of an object.

bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add a Py_SET_REFCNT() function to set the reference counter of an object.

bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: Convert PyType_HasFeature(), PyType_Check() and PyType_CheckExact() macros to static inline functions.

bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: In the limited C API, PyObject_INIT() and PyObject_INIT_VAR() are now defined as aliases to PyObject_Init() and PyObject_InitVar() to make their implementation opaque. It avoids to leak implementation details in the limited C API. Exclude the following functions from the limited C API: _Py_NewReference(), _Py_ForgetReference(), _PyTraceMalloc_NewReference() and _Py_GetRefTotal().

bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: Exclude trashcan mechanism from the limited C API: it requires access to PyTypeObject and PyThreadState structure fields, whereas these structures are opaque in the limited C API.

bpo-39511 [https://bugs.python.org/issue?@action=redirect&bpo=39511]: The PyThreadState_Clear() function now calls the PyThreadState.on_delete callback. Previously, that happened in PyThreadState_Delete().

bpo-38076 [https://bugs.python.org/issue?@action=redirect&bpo=38076]: Fix to clear the interpreter state only after clearing module globals to guarantee module state access from C Extensions during runtime destruction

bpo-39245 [https://bugs.python.org/issue?@action=redirect&bpo=39245]: The Vectorcall API (PEP 590) was made public, adding the functions PyObject_Vectorcall, PyObject_VectorcallMethod, PyVectorcall_Function, PyObject_CallOneArg, PyObject_CallMethodNoArgs, PyObject_CallMethodOneArg, PyObject_FastCallDict, and the flag Py_TPFLAGS_HAVE_VECTORCALL.

Python 3.9.0 alpha 3

Release date: 2020-01-24

Core and Builtins

bpo-39427 [https://bugs.python.org/issue?@action=redirect&bpo=39427]: Document all possibilities for the -X options in the command line help section. Patch by Pablo Galindo.

bpo-39421 [https://bugs.python.org/issue?@action=redirect&bpo=39421]: Fix possible crashes when operating with the functions in the heapq module and custom comparison operators.

bpo-39386 [https://bugs.python.org/issue?@action=redirect&bpo=39386]: Prevent double awaiting of async iterator.

bpo-17005 [https://bugs.python.org/issue?@action=redirect&bpo=17005]: Add functools.TopologicalSorter to the functools module to offers functionality to perform topological sorting of graphs. Patch by Pablo Galindo, Tim Peters and Larry Hastings.

bpo-39320 [https://bugs.python.org/issue?@action=redirect&bpo=39320]: Replace four complex bytecodes for building sequences with three simpler ones.

The following four bytecodes have been removed:

BUILD_LIST_UNPACK

BUILD_TUPLE_UNPACK

BUILD_SET_UNPACK

BUILD_TUPLE_UNPACK_WITH_CALL

The following three bytecodes have been added:

LIST_TO_TUPLE

LIST_EXTEND

SET_UPDATE

bpo-39336 [https://bugs.python.org/issue?@action=redirect&bpo=39336]: Import loaders which publish immutable module objects can now publish immutable packages in addition to individual modules.

bpo-39322 [https://bugs.python.org/issue?@action=redirect&bpo=39322]: Added a new function gc.is_finalized() to check if an object has been finalized by the garbage collector. Patch by Pablo Galindo.

bpo-39048 [https://bugs.python.org/issue?@action=redirect&bpo=39048]: Improve the displayed error message when incorrect types are passed to async with statements by looking up the __aenter__() special method before the __aexit__() special method when entering an asynchronous context manager. Patch by Géry Ogam.

bpo-39235 [https://bugs.python.org/issue?@action=redirect&bpo=39235]: Fix AST end location for lone generator expression in function call, e.g. f(i for i in a).

bpo-39209 [https://bugs.python.org/issue?@action=redirect&bpo=39209]: Correctly handle multi-line tokens in interactive mode. Patch by Pablo Galindo.

bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _json extension module to multiphase initialization (PEP 489 [https://peps.python.org/pep-0489/]).

bpo-39216 [https://bugs.python.org/issue?@action=redirect&bpo=39216]: Fix constant folding optimization for positional only arguments - by Anthony Sottile.

bpo-39215 [https://bugs.python.org/issue?@action=redirect&bpo=39215]: Fix SystemError when nested function has annotation on positional-only argument - by Anthony Sottile.

bpo-39200 [https://bugs.python.org/issue?@action=redirect&bpo=39200]: Correct the error message when calling the min() or max() with no arguments. Patch by Donghee Na.

bpo-39200 [https://bugs.python.org/issue?@action=redirect&bpo=39200]: Correct the error message when trying to construct range objects with no arguments. Patch by Pablo Galindo.

bpo-39166 [https://bugs.python.org/issue?@action=redirect&bpo=39166]: Fix incorrect line execution reporting in trace functions when tracing the last iteration of asynchronous for loops. Patch by Pablo Galindo.

bpo-39114 [https://bugs.python.org/issue?@action=redirect&bpo=39114]: Fix incorrect line execution reporting in trace functions when tracing exception handlers with name binding. Patch by Pablo Galindo.

bpo-39156 [https://bugs.python.org/issue?@action=redirect&bpo=39156]: Split the COMPARE_OP bytecode instruction into four distinct instructions.

COMPARE_OP for rich comparisons

IS_OP for ‘is’ and ‘is not’ tests

CONTAINS_OP for ‘in’ and ‘is not’ tests

JUMP_IF_NOT_EXC_MATCH for checking exceptions in ‘try-except’ statements.

This improves the clarity of the interpreter and should provide a modest speedup.

bpo-38588 [https://bugs.python.org/issue?@action=redirect&bpo=38588]: Fix possible crashes in dict and list when calling PyObject_RichCompareBool().

bpo-13601 [https://bugs.python.org/issue?@action=redirect&bpo=13601]: By default, sys.stderr is line-buffered now, even if stderr is redirected to a file. You can still make sys.stderr unbuffered by passing the -u command-line option or setting the PYTHONUNBUFFERED environment variable.

(Contributed by Jendrik Seipp in bpo-13601 [https://bugs.python.org/issue?@action=redirect&bpo=13601].)

bpo-38610 [https://bugs.python.org/issue?@action=redirect&bpo=38610]: Fix possible crashes in several list methods by holding strong references to list elements when calling PyObject_RichCompareBool().

bpo-32021 [https://bugs.python.org/issue?@action=redirect&bpo=32021]: Include brotli .br encoding in mimetypes encodings_map

Library

bpo-39430 [https://bugs.python.org/issue?@action=redirect&bpo=39430]: Fixed race condition in lazy imports in tarfile.

bpo-39413 [https://bugs.python.org/issue?@action=redirect&bpo=39413]: The os.unsetenv() function is now also available on Windows.

bpo-39390 [https://bugs.python.org/issue?@action=redirect&bpo=39390]: Fixed a regression with the ignore callback of shutil.copytree(). The argument types are now str and List[str] again.

bpo-39395 [https://bugs.python.org/issue?@action=redirect&bpo=39395]: The os.putenv() and os.unsetenv() functions are now always available.

bpo-39406 [https://bugs.python.org/issue?@action=redirect&bpo=39406]: If setenv() C function is available, os.putenv() is now implemented with setenv() instead of putenv(), so Python doesn’t have to handle the environment variable memory.

bpo-39396 [https://bugs.python.org/issue?@action=redirect&bpo=39396]: Fix math.nextafter(-0.0, +0.0) on AIX 7.1.

bpo-29435 [https://bugs.python.org/issue?@action=redirect&bpo=29435]: Allow tarfile.is_tarfile() to be used with file and file-like objects, like zipfile.is_zipfile(). Patch by William Woodruff.

bpo-39377 [https://bugs.python.org/issue?@action=redirect&bpo=39377]: Removed encoding option from json.loads(). It has been deprecated since Python 3.1.

bpo-39389 [https://bugs.python.org/issue?@action=redirect&bpo=39389]: Write accurate compression level metadata in gzip archives, rather than always signaling maximum compression.

bpo-39366 [https://bugs.python.org/issue?@action=redirect&bpo=39366]: The previously deprecated xpath() and xgtitle() methods of nntplib.NNTP have been removed.

bpo-39357 [https://bugs.python.org/issue?@action=redirect&bpo=39357]: Remove the buffering parameter of bz2.BZ2File. Since Python 3.0, it was ignored and using it was emitting DeprecationWarning. Pass an open file object, to control how the file is opened. The compresslevel parameter becomes keyword-only.

bpo-39353 [https://bugs.python.org/issue?@action=redirect&bpo=39353]: Deprecate binhex4 and hexbin4 standards. Deprecate the binhex module and the following binascii functions: b2a_hqx(), a2b_hqx(), rlecode_hqx(), rledecode_hqx(), crc_hqx().

bpo-39351 [https://bugs.python.org/issue?@action=redirect&bpo=39351]: Remove base64.encodestring() and base64.decodestring(), aliases deprecated since Python 3.1: use base64.encodebytes() and base64.decodebytes() instead.

bpo-39350 [https://bugs.python.org/issue?@action=redirect&bpo=39350]: Remove fractions.gcd() function, deprecated since Python 3.5 (bpo-22486 [https://bugs.python.org/issue?@action=redirect&bpo=22486]): use math.gcd() instead.

bpo-39329 [https://bugs.python.org/issue?@action=redirect&bpo=39329]: LMTP constructor now has an optional timeout parameter. Patch by Donghee Na.

bpo-39313 [https://bugs.python.org/issue?@action=redirect&bpo=39313]: Add a new exec_function option (–exec-function in the CLI) to RefactoringTool for making exec a function. Patch by Batuhan Taskaya.

bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: FTP_TLS and FTP_TLS now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Donghee Na.

bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: SMTP and SMTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Donghee Na.

bpo-39310 [https://bugs.python.org/issue?@action=redirect&bpo=39310]: Add math.ulp(): return the value of the least significant bit of a float.

bpo-39297 [https://bugs.python.org/issue?@action=redirect&bpo=39297]: Improved performance of importlib.metadata distribution discovery and resilients to inaccessible sys.path entries (importlib_metadata v1.4.0).

bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: NNTP and NNTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Donghee Na.

bpo-38901 [https://bugs.python.org/issue?@action=redirect&bpo=38901]: When you specify prompt=’.’ or equivalently python -m venv –prompt . … the basename of the current directory is used to set the created venv’s prompt when it’s activated.

bpo-39288 [https://bugs.python.org/issue?@action=redirect&bpo=39288]: Add math.nextafter(): return the next floating-point value after x towards y.

bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: POP3 and POP3_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Donghee Na.

bpo-39242 [https://bugs.python.org/issue?@action=redirect&bpo=39242]: Updated the Gmane domain from news.gmane.org to news.gmane.io which is used for examples of NNTP news reader server and nntplib tests.

bpo-35292 [https://bugs.python.org/issue?@action=redirect&bpo=35292]: Proxy the SimpleHTTPRequestHandler.guess_type to mimetypes.guess_type so the mimetypes.init is called lazily to avoid unnecessary costs when http.server module is imported.

bpo-39239 [https://bugs.python.org/issue?@action=redirect&bpo=39239]: The select.epoll.unregister() method no longer ignores the EBADF error.

bpo-38907 [https://bugs.python.org/issue?@action=redirect&bpo=38907]: In http.server script, restore binding to IPv4 on Windows.

bpo-39152 [https://bugs.python.org/issue?@action=redirect&bpo=39152]: Fix ttk.Scale.configure([name]) to return configuration tuple for name or all options. Giovanni Lombardo contributed part of the patch.

bpo-39198 [https://bugs.python.org/issue?@action=redirect&bpo=39198]: If an exception were to be thrown in Logger.isEnabledFor (say, by asyncio timeouts or stopit) , the logging global lock may not be released appropriately, resulting in deadlock. This change wraps that block of code with try...finally to ensure the lock is released.

bpo-39191 [https://bugs.python.org/issue?@action=redirect&bpo=39191]: Perform a check for running loop before starting a new task in loop.run_until_complete() to fail fast; it prevents the side effect of new task spawning before exception raising.

bpo-38871 [https://bugs.python.org/issue?@action=redirect&bpo=38871]: Correctly parenthesize filter-based statements that contain lambda expressions in lib2to3. Patch by Donghee Na.

bpo-39142 [https://bugs.python.org/issue?@action=redirect&bpo=39142]: A change was made to logging.config.dictConfig to avoid converting instances of named tuples to ConvertingTuple. It’s assumed that named tuples are too specialised to be treated like ordinary tuples; if a user of named tuples requires ConvertingTuple functionality, they will have to implement that themselves in their named tuple class.

bpo-39158 [https://bugs.python.org/issue?@action=redirect&bpo=39158]: ast.literal_eval() now supports empty sets.

bpo-39129 [https://bugs.python.org/issue?@action=redirect&bpo=39129]: Fix import path for asyncio.TimeoutError

bpo-39057 [https://bugs.python.org/issue?@action=redirect&bpo=39057]: urllib.request.proxy_bypass_environment() now ignores leading dots and no longer ignores a trailing newline.

bpo-39056 [https://bugs.python.org/issue?@action=redirect&bpo=39056]: Fixed handling invalid warning category in the -W option. No longer import the re module if it is not needed.

bpo-39055 [https://bugs.python.org/issue?@action=redirect&bpo=39055]: base64.b64decode() with validate=True raises now a binascii.Error if the input ends with a single \n.

bpo-21600 [https://bugs.python.org/issue?@action=redirect&bpo=21600]: Fix mock.patch.stopall() to stop active patches that were created with mock.patch.dict().

bpo-39019 [https://bugs.python.org/issue?@action=redirect&bpo=39019]: Implement dummy __class_getitem__ for tempfile.SpooledTemporaryFile.

bpo-39019 [https://bugs.python.org/issue?@action=redirect&bpo=39019]: Implement dummy __class_getitem__ for subprocess.Popen, subprocess.CompletedProcess

bpo-38914 [https://bugs.python.org/issue?@action=redirect&bpo=38914]: Adjusted the wording of the warning issued by distutils’ check command when the author and maintainer fields are supplied but no corresponding e-mail field (author_email or maintainer_email) is found. The wording now reflects the fact that these fields are suggested, but not required. Patch by Juergen Gmach.

bpo-38878 [https://bugs.python.org/issue?@action=redirect&bpo=38878]: Fixed __subclasshook__ of os.PathLike to return a correct result upon inheritance. Patch by Bar Harel.

bpo-38615 [https://bugs.python.org/issue?@action=redirect&bpo=38615]: IMAP4 and IMAP4_SSL now have an optional timeout parameter for their constructors. Also, the open() method now has an optional timeout parameter with this change. The overridden methods of IMAP4_SSL and IMAP4_stream were applied to this change. Patch by Donghee Na.

bpo-35182 [https://bugs.python.org/issue?@action=redirect&bpo=35182]: Fixed Popen.communicate() subsequent call crash when the child process has already closed any piped standard stream, but still continues to be running. Patch by Andriy Maletsky.

bpo-38630 [https://bugs.python.org/issue?@action=redirect&bpo=38630]: On Unix, subprocess.Popen.send_signal() now polls the process status. Polling reduces the risk of sending a signal to the wrong process if the process completed, the subprocess.Popen.returncode attribute is still None, and the pid has been reassigned (recycled) to a new different process.

bpo-38536 [https://bugs.python.org/issue?@action=redirect&bpo=38536]: Removes trailing space in formatted currency with international=True and a locale with symbol following value. E.g. locale.currency(12.34, international=True) returned '12,34 EUR ' instead of '12,34 EUR'.

bpo-38473 [https://bugs.python.org/issue?@action=redirect&bpo=38473]: Use signature from inner mock for autospecced methods attached with unittest.mock.attach_mock(). Patch by Karthikeyan Singaravelan.

bpo-38361 [https://bugs.python.org/issue?@action=redirect&bpo=38361]: Fixed an issue where ident could include a leading path separator when syslog.openlog() was called without arguments.

bpo-38293 [https://bugs.python.org/issue?@action=redirect&bpo=38293]: Add copy.copy() and copy.deepcopy() support to property() objects.

bpo-37958 [https://bugs.python.org/issue?@action=redirect&bpo=37958]: Added the pstats.Stats.get_profile_dict() method to return the profile data as a StatsProfile instance.

bpo-28367 [https://bugs.python.org/issue?@action=redirect&bpo=28367]: Termios magic constants for the following baud rates: - B500000 - B576000 - B921600 - B1000000 - B1152000 - B1500000 - B2000000 - B2500000 - B3000000 - B3500000 - B4000000 Patch by Andrey Smirnov

Documentation

bpo-39381 [https://bugs.python.org/issue?@action=redirect&bpo=39381]: Mention in docs that asyncio.get_event_loop() implicitly creates new event loop only if called from the main thread.

bpo-38918 [https://bugs.python.org/issue?@action=redirect&bpo=38918]: Add an entry for __module__ in the “function” & “method” sections of the inspect docs’ 형과 멤버 table.

bpo-3530 [https://bugs.python.org/issue?@action=redirect&bpo=3530]: In the ast module documentation, fix a misleading NodeTransformer example and add advice on when to use the fix_missing_locations function.

Build

bpo-39395 [https://bugs.python.org/issue?@action=redirect&bpo=39395]: On non-Windows platforms, the setenv() and unsetenv() functions are now required to build Python.

bpo-39160 [https://bugs.python.org/issue?@action=redirect&bpo=39160]: Updated the documentation in ./configure --help to show default values, reference documentation where required and add additional explanation where needed.

bpo-39144 [https://bugs.python.org/issue?@action=redirect&bpo=39144]: The ctags and etags build targets both include Modules/_ctypes and Python standard library source files.

IDLE

bpo-39050 [https://bugs.python.org/issue?@action=redirect&bpo=39050]: Make IDLE Settings dialog Help button work again.

bpo-34118 [https://bugs.python.org/issue?@action=redirect&bpo=34118]: Tag memoryview, range, and tuple as classes, the same as list, etcetera, in the library manual built-in functions list.

bpo-32989 [https://bugs.python.org/issue?@action=redirect&bpo=32989]: Add tests for editor newline_and_indent_event method. Remove dead code from pyparse find_good_parse_start method.

C API

bpo-39372 [https://bugs.python.org/issue?@action=redirect&bpo=39372]: Clean header files of interfaces defined but with no implementation. The public API symbols being removed are: _PyBytes_InsertThousandsGroupingLocale, _PyBytes_InsertThousandsGrouping, _Py_InitializeFromArgs, _Py_InitializeFromWideArgs, _PyFloat_Repr, _PyFloat_Digits, _PyFloat_DigitsInit, PyFrame_ExtendStack, _PyAIterWrapper_Type, PyNullImporter_Type, PyCmpWrapper_Type, PySortWrapper_Type, PyNoArgsFunction.

bpo-39164 [https://bugs.python.org/issue?@action=redirect&bpo=39164]: Add a private _PyErr_GetExcInfo() function to retrieve exception information of the specified Python thread state.

Python 3.9.0 alpha 2

Release date: 2019-12-18

Security

bpo-38945 [https://bugs.python.org/issue?@action=redirect&bpo=38945]: Newline characters have been escaped when performing uu encoding to prevent them from overflowing into to content section of the encoded file. This prevents malicious or accidental modification of data during the decoding process.

bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228]: Due to significant security concerns, the reuse_address parameter of asyncio.loop.create_datagram_endpoint() is no longer supported. This is because of the behavior of SO_REUSEADDR in UDP. For more details, see the documentation for loop.create_datagram_endpoint(). (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228 [https://bugs.python.org/issue?@action=redirect&bpo=37228].)

bpo-38804 [https://bugs.python.org/issue?@action=redirect&bpo=38804]: Fixes a ReDoS vulnerability in http.cookiejar. Patch by Ben Caller.

Core and Builtins

bpo-39028 [https://bugs.python.org/issue?@action=redirect&bpo=39028]: Slightly improve the speed of keyword argument parsing with many kwargs by strengthening the assumption that kwargs are interned strings.

bpo-39080 [https://bugs.python.org/issue?@action=redirect&bpo=39080]: Fix the value of end_col_offset for Starred Expression AST nodes when they are among the elements in the args attribute of Call AST nodes.

bpo-39031 [https://bugs.python.org/issue?@action=redirect&bpo=39031]: When parsing an “elif” node, lineno and col_offset of the node now point to the “elif” keyword and not to its condition, making it consistent with the “if” node. Patch by Lysandros Nikolaou.

bpo-20443 [https://bugs.python.org/issue?@action=redirect&bpo=20443]: In Python 3.9.0a1, sys.argv[0] was made an absolute path if a filename was specified on the command line. Revert this change, since most users expect sys.argv to be unmodified.

bpo-39008 [https://bugs.python.org/issue?@action=redirect&bpo=39008]: PySys_Audit() now requires Py_ssize_t to be used for size arguments in the format string, regardless of whether PY_SSIZE_T_CLEAN was defined at include time.

bpo-38673 [https://bugs.python.org/issue?@action=redirect&bpo=38673]: In REPL mode, don’t switch to PS2 if the line starts with comment or whitespace. Based on work by Batuhan Taşkaya.

bpo-38922 [https://bugs.python.org/issue?@action=redirect&bpo=38922]: Calling replace on a code object now raises the code.__new__ audit event.

bpo-38920 [https://bugs.python.org/issue?@action=redirect&bpo=38920]: Add audit hooks for when sys.excepthook() and sys.unraisablehook() are invoked.

bpo-38892 [https://bugs.python.org/issue?@action=redirect&bpo=38892]: Improve documentation for audit events table and functions.

bpo-38852 [https://bugs.python.org/issue?@action=redirect&bpo=38852]: Set the thread stack size to 8 Mb for debug builds on android platforms.

bpo-38858 [https://bugs.python.org/issue?@action=redirect&bpo=38858]: Each Python subinterpreter now has its own “small integer singletons”: numbers in [-5; 257] range. It is no longer possible to change the number of small integers at build time by overriding NSMALLNEGINTS and NSMALLPOSINTS macros: macros should now be modified manually in pycore_pystate.h header file.

bpo-36854 [https://bugs.python.org/issue?@action=redirect&bpo=36854]: The garbage collector state becomes per interpreter (PyInterpreterState.gc), rather than being global (_PyRuntimeState.gc).

bpo-38835 [https://bugs.python.org/issue?@action=redirect&bpo=38835]: The PyFPE_START_PROTECT() and PyFPE_END_PROTECT() macros are empty: they have been doing nothing for the last year, so stop using them.

bpo-38328 [https://bugs.python.org/issue?@action=redirect&bpo=38328]: Sped up the creation time of constant list and set displays. Patch by Brandt Bucher.

bpo-38707 [https://bugs.python.org/issue?@action=redirect&bpo=38707]: MainThread.native_id is now correctly reset in child processes spawned using multiprocessing.Process, instead of retaining the parent’s value.

bpo-38629 [https://bugs.python.org/issue?@action=redirect&bpo=38629]: Added __floor__ and __ceil__ methods to float object. Patch by Batuhan Taşkaya.

bpo-27145 [https://bugs.python.org/issue?@action=redirect&bpo=27145]: int + int and int - int operators can now return small integer singletons. Patch by hongweipeng.

bpo-38021 [https://bugs.python.org/issue?@action=redirect&bpo=38021]: Provide a platform tag for AIX that is sufficient for PEP425 binary distribution identification. Patch by Michael Felt.

bpo-35409 [https://bugs.python.org/issue?@action=redirect&bpo=35409]: Ignore GeneratorExit exceptions when throwing an exception into the aclose coroutine of an asynchronous generator.

bpo-33387 [https://bugs.python.org/issue?@action=redirect&bpo=33387]: Removed WITH_CLEANUP_START, WITH_CLEANUP_FINISH, BEGIN_FINALLY, END_FINALLY, CALL_FINALLY and POP_FINALLY bytecodes. Replaced with RERAISE and WITH_EXCEPT_START bytecodes. The compiler now generates different code for exceptional and non-exceptional branches for ‘with’ and ‘try-except’ statements. For ‘try-finally’ statements the ‘finally’ block is replicated for each exit from the ‘try’ body.

Library

bpo-39033 [https://bugs.python.org/issue?@action=redirect&bpo=39033]: Fix NameError in zipimport. Patch by Karthikeyan Singaravelan.

bpo-39022 [https://bugs.python.org/issue?@action=redirect&bpo=39022]: Update importlib.metadata to include improvements from importlib_metadata 1.3 including better serialization of EntryPoints and improved documentation for custom finders.

bpo-39006 [https://bugs.python.org/issue?@action=redirect&bpo=39006]: Fix asyncio when the ssl module is missing: only check for ssl.SSLSocket instance if the ssl module is available.

bpo-38708 [https://bugs.python.org/issue?@action=redirect&bpo=38708]: Fix a potential IndexError in email parser when parsing an empty msg-id.

bpo-38698 [https://bugs.python.org/issue?@action=redirect&bpo=38698]: Add a new InvalidMessageID token to email parser to represent invalid Message-ID headers. Also, add defects when there is remaining value after parsing the header.

bpo-38994 [https://bugs.python.org/issue?@action=redirect&bpo=38994]: Implement __class_getitem__ for os.PathLike, pathlib.Path.

bpo-38979 [https://bugs.python.org/issue?@action=redirect&bpo=38979]: Return class from ContextVar.__class_getitem__ to simplify subclassing.

bpo-38978 [https://bugs.python.org/issue?@action=redirect&bpo=38978]: Implement __class_getitem__ on asyncio objects (Future, Task, Queue). Patch by Batuhan Taskaya.

bpo-38916 [https://bugs.python.org/issue?@action=redirect&bpo=38916]: array.array: Remove tostring() and fromstring() methods. They were aliases to tobytes() and frombytes(), deprecated since Python 3.2.

bpo-38986 [https://bugs.python.org/issue?@action=redirect&bpo=38986]: Make repr of C accelerated TaskWakeupMethWrapper the same as of pure Python version.

bpo-38982 [https://bugs.python.org/issue?@action=redirect&bpo=38982]: Fix asyncio PidfdChildWatcher: handle waitpid() error. If waitpid() is called elsewhere, waitpid() call fails with ChildProcessError: use return code 255 in this case, and log a warning. It ensures that the pidfd file descriptor is closed if this error occurs.

bpo-38529 [https://bugs.python.org/issue?@action=redirect&bpo=38529]: Drop too noisy asyncio warning about deletion of a stream without explicit .close() call.

bpo-27413 [https://bugs.python.org/issue?@action=redirect&bpo=27413]: Added ability to pass through ensure_ascii options to json.dumps in the json.tool command-line interface.

bpo-38634 [https://bugs.python.org/issue?@action=redirect&bpo=38634]: The readline module now detects if Python is linked to libedit at runtime on all platforms. Previously, the check was only done on macOS.

bpo-33684 [https://bugs.python.org/issue?@action=redirect&bpo=33684]: Fix json.tool failed to read a JSON file with non-ASCII characters when locale encoding is not UTF-8.

bpo-38698 [https://bugs.python.org/issue?@action=redirect&bpo=38698]: Prevent UnboundLocalError to pop up in parse_message_id.

parse_message_id() was improperly using a token defined inside an exception handler, which was raising UnboundLocalError on parsing an invalid value. Patch by Claudiu Popa.

bpo-38927 [https://bugs.python.org/issue?@action=redirect&bpo=38927]: Use python -m pip instead of pip to upgrade dependencies in venv.

bpo-26730 [https://bugs.python.org/issue?@action=redirect&bpo=26730]: Fix SpooledTemporaryFile.rollover() might corrupt the file when it is in text mode. Patch by Serhiy Storchaka.

bpo-38881 [https://bugs.python.org/issue?@action=redirect&bpo=38881]: random.choices() now raises a ValueError when all the weights are zero.

bpo-38876 [https://bugs.python.org/issue?@action=redirect&bpo=38876]: Raise pickle.UnpicklingError when loading an item from memo for invalid input.

The previous code was raising a KeyError for both the Python and C implementation. This was caused by the specified index of an invalid input which did not exist in the memo structure, where the pickle stores what objects it has seen. The malformed input would have caused either a BINGET or LONG_BINGET load from the memo, leading to a KeyError as the determined index was bogus. Patch by Claudiu Popa.

bpo-38688 [https://bugs.python.org/issue?@action=redirect&bpo=38688]: Calling func:shutil.copytree to copy a directory tree from one directory to another subdirectory resulted in an endless loop and a RecursionError. A fix was added to consume an iterator and create the list of the entries to be copied, avoiding the recursion for newly created directories. Patch by Bruno P. Kinoshita.

bpo-38863 [https://bugs.python.org/issue?@action=redirect&bpo=38863]: Improve is_cgi() function in http.server, which enables processing the case that cgi directory is a child of another directory other than root.

bpo-37838 [https://bugs.python.org/issue?@action=redirect&bpo=37838]: typing.get_type_hints() properly handles functions decorated with functools.wraps().

bpo-38870 [https://bugs.python.org/issue?@action=redirect&bpo=38870]: Expose ast.unparse() as a function of the ast module that can be used to unparse an ast.AST object and produce a string with code that would produce an equivalent ast.AST object when parsed. Patch by Pablo Galindo and Batuhan Taskaya.

bpo-38859 [https://bugs.python.org/issue?@action=redirect&bpo=38859]: AsyncMock now returns StopAsyncIteration on the exhaustion of a side_effects iterable. Since PEP-479 its Impossible to raise a StopIteration exception from a coroutine.

bpo-38857 [https://bugs.python.org/issue?@action=redirect&bpo=38857]: AsyncMock fix for return values that are awaitable types. This also covers side_effect iterable values that happened to be awaitable, and wraps callables that return an awaitable type. Before these awaitables were being awaited instead of being returned as is.

bpo-38834 [https://bugs.python.org/issue?@action=redirect&bpo=38834]: typing.TypedDict subclasses now track which keys are optional using the __required_keys__ and __optional_keys__ attributes, to enable runtime validation by downstream projects. Patch by Zac Hatfield-Dodds.

bpo-38821 [https://bugs.python.org/issue?@action=redirect&bpo=38821]: Fix unhandled exceptions in argparse when internationalizing error messages for arguments with nargs set to special (non-integer) values. Patch by Federico Bond.

bpo-38820 [https://bugs.python.org/issue?@action=redirect&bpo=38820]: Make Python compatible with OpenSSL 3.0.0. ssl.SSLSocket.getpeercert() no longer returns IPv6 addresses with a trailing new line.

bpo-38811 [https://bugs.python.org/issue?@action=redirect&bpo=38811]: Fix an unhandled exception in pathlib when os.link() is missing. Patch by Toke Høiland-Jørgensen.

bpo-38686 [https://bugs.python.org/issue?@action=redirect&bpo=38686]: Added support for multiple qop values in urllib.request.AbstractDigestAuthHandler.

bpo-38712 [https://bugs.python.org/issue?@action=redirect&bpo=38712]: Add the Linux-specific signal.pidfd_send_signal() function, which allows sending a signal to a process identified by a file descriptor rather than a pid.

bpo-38348 [https://bugs.python.org/issue?@action=redirect&bpo=38348]: Add -i and --indent (indentation level), and --no-type-comments (type comments) command line options to ast parsing tool.

bpo-37523 [https://bugs.python.org/issue?@action=redirect&bpo=37523]: Change zipfile.ZipExtFile to raise ValueError when trying to access the underlying file object after it has been closed. This new behavior is consistent with how accessing closed files is handled in other parts of Python.

bpo-38045 [https://bugs.python.org/issue?@action=redirect&bpo=38045]: Improve the performance of enum._decompose() in enum. Patch by hongweipeng.

bpo-36820 [https://bugs.python.org/issue?@action=redirect&bpo=36820]: Break cycle generated when saving an exception in socket.py, codeop.py and dyld.py as they keep alive not only the exception but user objects through the __traceback__ attribute. Patch by Mario Corchero.

bpo-36406 [https://bugs.python.org/issue?@action=redirect&bpo=36406]: Handle namespace packages in doctest. Patch by Karthikeyan Singaravelan.

bpo-34776 [https://bugs.python.org/issue?@action=redirect&bpo=34776]: Fix dataclasses to support forward references in type annotations

bpo-20928 [https://bugs.python.org/issue?@action=redirect&bpo=20928]: ElementTree supports recursive XInclude processing. Patch by Stefan Behnel.

bpo-29636 [https://bugs.python.org/issue?@action=redirect&bpo=29636]: Add whitespace options for formatting JSON with the json.tool CLI. The following mutually exclusive options are now supported: --indent for setting the indent level in spaces; --tab for indenting with tabs; --no-indent for suppressing newlines; and --compact for suppressing all whitespace. The default behavior remains the same as --indent=4.

Documentation

bpo-38928 [https://bugs.python.org/issue?@action=redirect&bpo=38928]: Correct when venv’s upgrade_dependencies() and --upgrade-deps are added.

bpo-38899 [https://bugs.python.org/issue?@action=redirect&bpo=38899]: Update documentation to state that to activate virtual environments under fish one should use source, not . as documented at https://fishshell.com/docs/current/cmds/source.html.

bpo-22377 [https://bugs.python.org/issue?@action=redirect&bpo=22377]: Improves documentation of the values that datetime.datetime.strptime() accepts for %Z. Patch by Karl Dubost.

Tests

bpo-38546 [https://bugs.python.org/issue?@action=redirect&bpo=38546]: Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly stop the manager to prevent leaking a child process running in the background after the test completes.

bpo-38546 [https://bugs.python.org/issue?@action=redirect&bpo=38546]: Multiprocessing and concurrent.futures tests now stop the resource tracker process when tests complete.

bpo-38614 [https://bugs.python.org/issue?@action=redirect&bpo=38614]: Replace hardcoded timeout constants in tests with new test.support constants: LOOPBACK_TIMEOUT, INTERNET_TIMEOUT, SHORT_TIMEOUT and LONG_TIMEOUT. It becomes easier to adjust these four timeout constants for all tests at once, rather than having to adjust every single test file.

bpo-38547 [https://bugs.python.org/issue?@action=redirect&bpo=38547]: Fix test_pty: if the process is the session leader, closing the master file descriptor raises a SIGHUP signal: simply ignore SIGHUP when running the tests.

bpo-38992 [https://bugs.python.org/issue?@action=redirect&bpo=38992]: Fix a test for math.fsum() that was failing due to constant folding.

bpo-38991 [https://bugs.python.org/issue?@action=redirect&bpo=38991]: test.support: run_python_until_end(), assert_python_ok() and assert_python_failure() functions no longer strip whitespaces from stderr. Remove test.support.strip_python_stderr() function.

bpo-38965 [https://bugs.python.org/issue?@action=redirect&bpo=38965]: Fix test_faulthandler on GCC 10. Use the “volatile” keyword in faulthandler._stack_overflow() to prevent tail call optimization on any compiler, rather than relying on compiler specific pragma.

bpo-38875 [https://bugs.python.org/issue?@action=redirect&bpo=38875]: test_capi: trashcan tests now require the test “cpu” resource.

bpo-38841 [https://bugs.python.org/issue?@action=redirect&bpo=38841]: Skip asyncio test_create_datagram_endpoint_existing_sock_unix on platforms lacking a functional bind() for named unix domain sockets.

bpo-38692 [https://bugs.python.org/issue?@action=redirect&bpo=38692]: Skip the test_posix.test_pidfd_open() test if os.pidfd_open() fails with a PermissionError. This situation can happen in a Linux sandbox using a syscall whitelist which doesn’t allow the pidfd_open() syscall yet.

bpo-38839 [https://bugs.python.org/issue?@action=redirect&bpo=38839]: Fix some unused functions in tests. Patch by Adam Johnson.

bpo-38669 [https://bugs.python.org/issue?@action=redirect&bpo=38669]: Raise TypeError when passing target as a string with unittest.mock.patch.object().

bpo-37957 [https://bugs.python.org/issue?@action=redirect&bpo=37957]: test.regrtest now can receive a list of test patterns to ignore (using the -i/–ignore argument) or a file with a list of patterns to ignore (using the –ignore-file argument). Patch by Pablo Galindo.

Build

bpo-37404 [https://bugs.python.org/issue?@action=redirect&bpo=37404]: asyncio now raises TypeError when calling incompatible methods with an ssl.SSLSocket socket. Patch by Ido Michael.

bpo-36500 [https://bugs.python.org/issue?@action=redirect&bpo=36500]: Added an optional “regen” project to the Visual Studio solution that will regenerate all grammar, tokens, and opcodes.

Windows

bpo-39007 [https://bugs.python.org/issue?@action=redirect&bpo=39007]: Add auditing events to functions in winreg.

bpo-33125 [https://bugs.python.org/issue?@action=redirect&bpo=33125]: Add support for building and releasing Windows ARM64 packages.

macOS

bpo-37931 [https://bugs.python.org/issue?@action=redirect&bpo=37931]: Fixed a crash on OSX dynamic builds that occurred when re-initializing the posix module after a Py_Finalize if the environment had changed since the previous import posix. Patch by Benoît Hudson.

IDLE

bpo-38944 [https://bugs.python.org/issue?@action=redirect&bpo=38944]: Escape key now closes IDLE completion windows. Patch by Johnny Najera.

bpo-38943 [https://bugs.python.org/issue?@action=redirect&bpo=38943]: Fix IDLE autocomplete windows not always appearing on some systems. Patch by Johnny Najera.

bpo-38862 [https://bugs.python.org/issue?@action=redirect&bpo=38862]: ‘Strip Trailing Whitespace’ on the Format menu removes extra newlines at the end of non-shell files.

bpo-38636 [https://bugs.python.org/issue?@action=redirect&bpo=38636]: Fix IDLE Format menu tab toggle and file indent width. These functions (default shortcuts Alt-T and Alt-U) were mistakenly disabled in 3.7.5 and 3.8.0.

C API

bpo-38896 [https://bugs.python.org/issue?@action=redirect&bpo=38896]: Remove PyUnicode_ClearFreeList() function: the Unicode free list has been removed in Python 3.3.

bpo-37340 [https://bugs.python.org/issue?@action=redirect&bpo=37340]: Remove PyMethod_ClearFreeList() and PyCFunction_ClearFreeList() functions: the free lists of bound method objects have been removed.

bpo-38835 [https://bugs.python.org/issue?@action=redirect&bpo=38835]: Exclude PyFPE_START_PROTECT() and PyFPE_END_PROTECT() macros of pyfpe.h from Py_LIMITED_API (stable API).

Python 3.9.0 alpha 1

Release date: 2019-11-19

Security

bpo-38722 [https://bugs.python.org/issue?@action=redirect&bpo=38722]: runpy now uses io.open_code() to open code files. Patch by Jason Killen.

bpo-38622 [https://bugs.python.org/issue?@action=redirect&bpo=38622]: Add additional audit events for the ctypes module.

bpo-38418 [https://bugs.python.org/issue?@action=redirect&bpo=38418]: Fixes audit event for os.system() to be named os.system.

bpo-38243 [https://bugs.python.org/issue?@action=redirect&bpo=38243]: Escape the server title of xmlrpc.server.DocXMLRPCServer when rendering the document page as HTML. (Contributed by Donghee Na in bpo-38243 [https://bugs.python.org/issue?@action=redirect&bpo=38243].)

bpo-38174 [https://bugs.python.org/issue?@action=redirect&bpo=38174]: Update vendorized expat library version to 2.2.8, which resolves CVE 2019-15903 [https://www.cve.org/CVERecord?id=CVE-2019-15903].

bpo-37764 [https://bugs.python.org/issue?@action=redirect&bpo=37764]: Fixes email._header_value_parser.get_unstructured going into an infinite loop for a specific case in which the email header does not have trailing whitespace, and the case in which it contains an invalid encoded word. Patch by Ashwin Ramaswami.

bpo-37461 [https://bugs.python.org/issue?@action=redirect&bpo=37461]: Fix an infinite loop when parsing specially crafted email headers. Patch by Abhilash Raj.

bpo-37363 [https://bugs.python.org/issue?@action=redirect&bpo=37363]: Adds audit events for the range of supported run commands (see 명령 줄과 환경).

bpo-37463 [https://bugs.python.org/issue?@action=redirect&bpo=37463]: ssl.match_hostname() no longer accepts IPv4 addresses with additional text after the address and only quad-dotted notation without trailing whitespaces. Some inet_aton() implementations ignore whitespace and all data after whitespace, e.g. ‘127.0.0.1 whatever’.

bpo-37363 [https://bugs.python.org/issue?@action=redirect&bpo=37363]: Adds audit events for ensurepip, ftplib, glob, imaplib, nntplib, pdb, poplib, shutil, smtplib, sqlite3, subprocess, telnetlib, tempfile and webbrowser, as well as os.listdir(), os.scandir() and breakpoint().

bpo-37364 [https://bugs.python.org/issue?@action=redirect&bpo=37364]: io.open_code() is now used when reading .pth files.

bpo-34631 [https://bugs.python.org/issue?@action=redirect&bpo=34631]: Updated OpenSSL to 1.1.1c in Windows installer

bpo-34155 [https://bugs.python.org/issue?@action=redirect&bpo=34155]: Fix parsing of invalid email addresses with more than one @ (e.g. a@b@c.com.) to not return the part before 2nd @ as valid email address. Patch by maxking & jpic.

Core and Builtins

bpo-38631 [https://bugs.python.org/issue?@action=redirect&bpo=38631]: Replace Py_FatalError() call with a regular RuntimeError exception in float.__getformat__().

bpo-38639 [https://bugs.python.org/issue?@action=redirect&bpo=38639]: Optimized math.floor(), math.ceil() and math.trunc() for floats.

bpo-38640 [https://bugs.python.org/issue?@action=redirect&bpo=38640]: Fixed a bug in the compiler that was causing to raise in the presence of break statements and continue statements inside always false while loops. Patch by Pablo Galindo.

bpo-38613 [https://bugs.python.org/issue?@action=redirect&bpo=38613]: Optimized some set operations (e.g. |, ^, and -) of dict_keys. d.keys() | other was slower than set(d) | other but they are almost same performance for now.

bpo-28029 [https://bugs.python.org/issue?@action=redirect&bpo=28029]: "".replace("", s, n) now returns s instead of an empty string for all non-zero n. There are similar changes for bytes and bytearray objects.

bpo-38535 [https://bugs.python.org/issue?@action=redirect&bpo=38535]: Fixed line numbers and column offsets for AST nodes for calls without arguments in decorators.

bpo-38525 [https://bugs.python.org/issue?@action=redirect&bpo=38525]: Fix a segmentation fault when using reverse iterators of empty dict objects. Patch by Donghee Na and Inada Naoki.

bpo-38465 [https://bugs.python.org/issue?@action=redirect&bpo=38465]: bytearray, array and mmap objects allow now to export more than 2**31 buffers at a time.

bpo-38469 [https://bugs.python.org/issue?@action=redirect&bpo=38469]: Fixed a bug where the scope of named expressions was not being resolved correctly in the presence of the global keyword. Patch by Pablo Galindo.

bpo-38437 [https://bugs.python.org/issue?@action=redirect&bpo=38437]: Activate the GC_DEBUG macro for debug builds of the interpreter (when Py_DEBUG is set). Patch by Pablo Galindo.

bpo-38379 [https://bugs.python.org/issue?@action=redirect&bpo=38379]: When the garbage collector makes a collection in which some objects resurrect (they are reachable from outside the isolated cycles after the finalizers have been executed), do not block the collection of all objects that are still unreachable. Patch by Pablo Galindo and Tim Peters.

bpo-38379 [https://bugs.python.org/issue?@action=redirect&bpo=38379]: When cyclic garbage collection (gc) runs finalizers that resurrect unreachable objects, the current gc run ends, without collecting any cyclic trash. However, the statistics reported by collect() and get_stats() claimed that all cyclic trash found was collected, and that the resurrected objects were collected. Changed the stats to report that none were collected.

bpo-38392 [https://bugs.python.org/issue?@action=redirect&bpo=38392]: In debug mode, PyObject_GC_Track() now calls tp_traverse() of the object type to ensure that the object is valid: test that objects visited by tp_traverse() are valid.

bpo-38210 [https://bugs.python.org/issue?@action=redirect&bpo=38210]: Remove unnecessary intersection and update set operation in dictview with empty set. (Contributed by Donghee Na in bpo-38210 [https://bugs.python.org/issue?@action=redirect&bpo=38210].)

bpo-38402 [https://bugs.python.org/issue?@action=redirect&bpo=38402]: Check the error from the system’s underlying crypt or crypt_r.

bpo-37474 [https://bugs.python.org/issue?@action=redirect&bpo=37474]: On FreeBSD, Python no longer calls fedisableexcept() at startup to control the floating-point control mode. The call became useless since FreeBSD 6: it became the default mode.

bpo-38006 [https://bugs.python.org/issue?@action=redirect&bpo=38006]: Fix a bug due to the interaction of weakrefs and the cyclic garbage collector. We must clear any weakrefs in garbage in order to prevent their callbacks from executing and causing a crash.

bpo-38317 [https://bugs.python.org/issue?@action=redirect&bpo=38317]: Fix warnings options priority: PyConfig.warnoptions has the highest priority, as stated in the PEP 587 [https://peps.python.org/pep-0587/].

bpo-38310 [https://bugs.python.org/issue?@action=redirect&bpo=38310]: Predict BUILD_MAP_UNPACK_WITH_CALL -> CALL_FUNCTION_EX opcode pairs in the main interpreter loop. Patch by Brandt Bucher.

bpo-36871 [https://bugs.python.org/issue?@action=redirect&bpo=36871]: Improve error handling for the assert_has_calls and assert_has_awaits methods of mocks. Fixed a bug where any errors encountered while binding the expected calls to the mock’s spec were silently swallowed, leading to misleading error output.

bpo-11410 [https://bugs.python.org/issue?@action=redirect&bpo=11410]: Better control over symbol visibility is provided through use of the visibility attributes available in gcc >= 4.0, provided in a uniform way across POSIX and Windows. The POSIX build files have been updated to compile with -fvisibility=hidden, minimising exported symbols.

bpo-38219 [https://bugs.python.org/issue?@action=redirect&bpo=38219]: Optimized the dict constructor and the update() method for the case when the argument is a dict.

bpo-38236 [https://bugs.python.org/issue?@action=redirect&bpo=38236]: Python now dumps path configuration if it fails to import the Python codecs of the filesystem and stdio encodings.

bpo-38013 [https://bugs.python.org/issue?@action=redirect&bpo=38013]: Allow to call async_generator_athrow().throw(...) even for non-started async generator helper. It fixes annoying warning at the end of asyncio.run() call.

bpo-38124 [https://bugs.python.org/issue?@action=redirect&bpo=38124]: Fix an off-by-one error in PyState_AddModule that could cause out-of-bounds memory access.

bpo-38116 [https://bugs.python.org/issue?@action=redirect&bpo=38116]: The select module is now PEP-384 compliant and no longer has static state

bpo-38113 [https://bugs.python.org/issue?@action=redirect&bpo=38113]: ast module updated to PEP-384 and all statics removed

bpo-38076 [https://bugs.python.org/issue?@action=redirect&bpo=38076]: The struct module is now PEP-384 compatible

bpo-38075 [https://bugs.python.org/issue?@action=redirect&bpo=38075]: The random module is now PEP-384 compatible

bpo-38074 [https://bugs.python.org/issue?@action=redirect&bpo=38074]: zlib module made PEP-384 compatible

bpo-38073 [https://bugs.python.org/issue?@action=redirect&bpo=38073]: Make pwd extension module PEP-384 compatible

bpo-38072 [https://bugs.python.org/issue?@action=redirect&bpo=38072]: grp module made PEP-384 compatible

bpo-38069 [https://bugs.python.org/issue?@action=redirect&bpo=38069]: Make _posixsubprocess PEP-384 compatible

bpo-38071 [https://bugs.python.org/issue?@action=redirect&bpo=38071]: Make termios extension module PEP-384 compatible

bpo-38005 [https://bugs.python.org/issue?@action=redirect&bpo=38005]: Fixed comparing and creating of InterpreterID and ChannelID.

bpo-36946 [https://bugs.python.org/issue?@action=redirect&bpo=36946]: Fix possible signed integer overflow when handling slices. Patch by hongweipeng.

bpo-37994 [https://bugs.python.org/issue?@action=redirect&bpo=37994]: Fixed silencing arbitrary errors if an attribute lookup fails in several sites. Only AttributeError should be silenced.

bpo-8425 [https://bugs.python.org/issue?@action=redirect&bpo=8425]: Optimize set difference_update for the case when the other set is much larger than the base set. (Suggested by Evgeny Kapun with code contributed by Michele Orrù).

bpo-37966 [https://bugs.python.org/issue?@action=redirect&bpo=37966]: The implementation of is_normalized() has been greatly sped up on strings that aren’t normalized, by implementing the full normalization-quick-check algorithm from the Unicode standard.

bpo-37947 [https://bugs.python.org/issue?@action=redirect&bpo=37947]: Adjust correctly the recursion level in the symtable generation for named expressions. Patch by Pablo Galindo.

bpo-37812 [https://bugs.python.org/issue?@action=redirect&bpo=37812]: The CHECK_SMALL_INT macro used inside Object/longobject.c has been replaced with an explicit return at each call site.

bpo-37751 [https://bugs.python.org/issue?@action=redirect&bpo=37751]: Fix codecs.lookup() to normalize the encoding name the same way than encodings.normalize_encoding(), except that codecs.lookup() also converts the name to lower case.

bpo-37830 [https://bugs.python.org/issue?@action=redirect&bpo=37830]: Fixed compilation of break and continue in the finally block when the corresponding try block contains return with a non-constant value.

bpo-20490 [https://bugs.python.org/issue?@action=redirect&bpo=20490]: Improve import error message for partially initialized module on circular from imports - by Anthony Sottile.

bpo-37840 [https://bugs.python.org/issue?@action=redirect&bpo=37840]: Fix handling of negative indices in sq_item of bytearray. Patch by Sergey Fedoseev.

bpo-37802 [https://bugs.python.org/issue?@action=redirect&bpo=37802]: Slightly improve performance of PyLong_FromUnsignedLong(), PyLong_FromUnsignedLongLong() and PyLong_FromSize_t(). Patch by Sergey Fedoseev.

bpo-37409 [https://bugs.python.org/issue?@action=redirect&bpo=37409]: Ensure explicit relative imports from interactive sessions and scripts (having no parent package) always raise ImportError, rather than treating the current module as the package. Patch by Ben Lewis.

bpo-32912 [https://bugs.python.org/issue?@action=redirect&bpo=32912]: Reverted bpo-32912 [https://bugs.python.org/issue?@action=redirect&bpo=32912]: emitting SyntaxWarning instead of DeprecationWarning for invalid escape sequences in string and bytes literals.

bpo-37757 [https://bugs.python.org/issue?@action=redirect&bpo=37757]: PEP 572 [https://peps.python.org/pep-0572/]: As described in the PEP, assignment expressions now raise SyntaxError when their interaction with comprehension scoping results in an ambiguous target scope.

The TargetScopeError subclass originally proposed by the PEP has been removed in favour of just raising regular syntax errors for the disallowed cases.

bpo-36279 [https://bugs.python.org/issue?@action=redirect&bpo=36279]: Fix potential use of uninitialized memory in os.wait3().

bpo-36311 [https://bugs.python.org/issue?@action=redirect&bpo=36311]: Decoding bytes objects larger than 2GiB is faster and no longer fails when a multibyte characters spans a chunk boundary.

bpo-34880 [https://bugs.python.org/issue?@action=redirect&bpo=34880]: The assert statement now works properly if the AssertionError exception is being shadowed. Patch by Zackery Spytz.

bpo-37340 [https://bugs.python.org/issue?@action=redirect&bpo=37340]: Removed object cache (free_list) for bound method objects. Temporary bound method objects are less used than before thanks to the LOAD_METHOD opcode and the _PyObject_VectorcallMethod C API.

bpo-37648 [https://bugs.python.org/issue?@action=redirect&bpo=37648]: Fixed minor inconsistency in list.__contains__(), tuple.__contains__() and a few other places. The collection’s item is now always at the left and the needle is on the right of ==.

bpo-37444 [https://bugs.python.org/issue?@action=redirect&bpo=37444]: Update differing exception between builtins.__import__() and importlib.__import__().

bpo-37619 [https://bugs.python.org/issue?@action=redirect&bpo=37619]: When adding a wrapper descriptor from one class to a different class (for example, setting __add__ = str.__add__ on an int subclass), an exception is correctly raised when the operator is called.

bpo-37593 [https://bugs.python.org/issue?@action=redirect&bpo=37593]: Swap the positions of the posonlyargs and args parameters in the constructor of ast.parameters nodes.

bpo-37543 [https://bugs.python.org/issue?@action=redirect&bpo=37543]: Optimized pymalloc for non PGO build.

bpo-37537 [https://bugs.python.org/issue?@action=redirect&bpo=37537]: Compute allocated pymalloc blocks inside _Py_GetAllocatedBlocks(). This slows down _Py_GetAllocatedBlocks() but gives a small speedup to _PyObject_Malloc() and _PyObject_Free().

bpo-37467 [https://bugs.python.org/issue?@action=redirect&bpo=37467]: Fix sys.excepthook() and PyErr_Display() if a filename is a bytes string. For example, for a SyntaxError exception where the filename attribute is a bytes string.

bpo-37433 [https://bugs.python.org/issue?@action=redirect&bpo=37433]: Fix SyntaxError indicator printing too many spaces for multi-line strings - by Anthony Sottile.

bpo-37417 [https://bugs.python.org/issue?@action=redirect&bpo=37417]: bytearray.extend() now correctly handles errors that arise during iteration. Patch by Brandt Bucher.

bpo-37414 [https://bugs.python.org/issue?@action=redirect&bpo=37414]: The undocumented sys.callstats() function has been removed. Since Python 3.7, it was deprecated and always returned None. It required a special build option CALL_PROFILE which was already removed in Python 3.7.

bpo-37392 [https://bugs.python.org/issue?@action=redirect&bpo=37392]: Remove sys.getcheckinterval() and sys.setcheckinterval() functions. They were deprecated since Python 3.2. Use sys.getswitchinterval() and sys.setswitchinterval() instead. Remove also check_interval field of the PyInterpreterState structure.

bpo-37388 [https://bugs.python.org/issue?@action=redirect&bpo=37388]: In development mode and in debug build, encoding and errors arguments are now checked on string encoding and decoding operations. Examples: open(), str.encode() and bytes.decode().

By default, for best performances, the errors argument is only checked at the first encoding/decoding error, and the encoding argument is sometimes ignored for empty strings.

bpo-37348 [https://bugs.python.org/issue?@action=redirect&bpo=37348]: Optimized decoding short ASCII string with UTF-8 and ascii codecs. b"foo".decode() is about 15% faster. Patch by Inada Naoki.

bpo-24214 [https://bugs.python.org/issue?@action=redirect&bpo=24214]: Improved support of the surrogatepass error handler in the UTF-8 and UTF-16 incremental decoders.

bpo-37330 [https://bugs.python.org/issue?@action=redirect&bpo=37330]: open(), io.open(), codecs.open() and fileinput.FileInput no longer accept 'U' (“universal newline”) in the file mode. This flag was deprecated since Python 3.3.

bpo-35224 [https://bugs.python.org/issue?@action=redirect&bpo=35224]: Reverse evaluation order of key: value in dict comprehensions as proposed in PEP 572. I.e. in {k: v for ...}, k will be evaluated before v.

bpo-37316 [https://bugs.python.org/issue?@action=redirect&bpo=37316]: Fix the PySys_Audit() call in mmap.mmap.

bpo-37300 [https://bugs.python.org/issue?@action=redirect&bpo=37300]: Remove an unnecessary Py_XINCREF in classobject.c.

bpo-37269 [https://bugs.python.org/issue?@action=redirect&bpo=37269]: Fix a bug in the peephole optimizer that was not treating correctly constant conditions with binary operators. Patch by Pablo Galindo.

bpo-20443 [https://bugs.python.org/issue?@action=redirect&bpo=20443]: Python now gets the absolute path of the script filename specified on the command line (ex: “python3 script.py”): the __file__ attribute of the __main__ module and sys.path[0] become an absolute path, rather than a relative path.

bpo-37257 [https://bugs.python.org/issue?@action=redirect&bpo=37257]: Python’s small object allocator (obmalloc.c) now allows (no more than) one empty arena to remain available for immediate reuse, without returning it to the OS. This prevents thrashing in simple loops where an arena could be created and destroyed anew on each iteration.

bpo-37231 [https://bugs.python.org/issue?@action=redirect&bpo=37231]: The dispatching of type slots to special methods (for example calling __mul__ when doing x * y) has been made faster.

bpo-36974 [https://bugs.python.org/issue?@action=redirect&bpo=36974]: Implemented separate vectorcall functions for every calling convention of builtin functions and methods. This improves performance for calls.

bpo-37213 [https://bugs.python.org/issue?@action=redirect&bpo=37213]: Handle correctly negative line offsets in the peephole optimizer. Patch by Pablo Galindo.

bpo-37219 [https://bugs.python.org/issue?@action=redirect&bpo=37219]: Remove erroneous optimization for empty set differences.

bpo-15913 [https://bugs.python.org/issue?@action=redirect&bpo=15913]: Implement PyBuffer_SizeFromFormat() function (previously documented but not implemented): call struct.calcsize(). Patch by Joannah Nanjekye.

bpo-36922 [https://bugs.python.org/issue?@action=redirect&bpo=36922]: Slot functions optimize any callable with Py_TPFLAGS_METHOD_DESCRIPTOR instead of only instances of function.

bpo-36974 [https://bugs.python.org/issue?@action=redirect&bpo=36974]: The slot tp_vectorcall_offset is inherited unconditionally to support super().__call__() when the base class uses vectorcall.

bpo-37160 [https://bugs.python.org/issue?@action=redirect&bpo=37160]: threading.get_native_id() now also supports NetBSD.

bpo-37077 [https://bugs.python.org/issue?@action=redirect&bpo=37077]: Add threading.get_native_id() support for AIX. Patch by M. Felt

bpo-36781 [https://bugs.python.org/issue?@action=redirect&bpo=36781]: sum() has been optimized for boolean values.

bpo-34556 [https://bugs.python.org/issue?@action=redirect&bpo=34556]: Add --upgrade-deps to venv module. Patch by Cooper Ry Lees

bpo-20523 [https://bugs.python.org/issue?@action=redirect&bpo=20523]: pdb.Pdb supports ~/.pdbrc in Windows 7. Patch by Tim Hopper and Dan Lidral-Porter.

bpo-35551 [https://bugs.python.org/issue?@action=redirect&bpo=35551]: Updated encodings: - Removed the “tis260” encoding, which was an alias for the nonexistent “tactis” codec. - Added “mac_centeuro” as an alias for the mac_latin2 encoding.

bpo-19072 [https://bugs.python.org/issue?@action=redirect&bpo=19072]: The classmethod decorator can now wrap other descriptors such as property objects. Adapted from a patch written by Graham Dumpleton.

bpo-27575 [https://bugs.python.org/issue?@action=redirect&bpo=27575]: Improve speed of dictview intersection by directly using set intersection logic. Patch by David Su.

bpo-30773 [https://bugs.python.org/issue?@action=redirect&bpo=30773]: Prohibit parallel running of aclose() / asend() / athrow(). Fix ag_running to reflect the actual running status of the AG.

Library

bpo-36589 [https://bugs.python.org/issue?@action=redirect&bpo=36589]: The curses.update_lines_cols() function now returns None instead of 1 on success.

bpo-38807 [https://bugs.python.org/issue?@action=redirect&bpo=38807]: Update TypeError messages for os.path.join() to include os.PathLike objects as acceptable input types.

bpo-38724 [https://bugs.python.org/issue?@action=redirect&bpo=38724]: Add a repr for subprocess.Popen objects. Patch by Andrey Doroschenko.

bpo-38786 [https://bugs.python.org/issue?@action=redirect&bpo=38786]: pydoc now recognizes and parses HTTPS URLs. Patch by python273.

bpo-38785 [https://bugs.python.org/issue?@action=redirect&bpo=38785]: Prevent asyncio from crashing if parent __init__ is not called from a constructor of object derived from asyncio.Future.

bpo-38723 [https://bugs.python.org/issue?@action=redirect&bpo=38723]: pdb now uses io.open_code() to trigger auditing events.

bpo-27805 [https://bugs.python.org/issue?@action=redirect&bpo=27805]: Allow opening pipes and other non-seekable files in append mode with open().

bpo-38438 [https://bugs.python.org/issue?@action=redirect&bpo=38438]: Simplify the argparse usage message for nargs="*".

bpo-38761 [https://bugs.python.org/issue?@action=redirect&bpo=38761]: WeakSet is now registered as a collections.abc.MutableSet.

bpo-38716 [https://bugs.python.org/issue?@action=redirect&bpo=38716]: logging: change RotatingHandler namer and rotator to class-level attributes. This stops __init__ from setting them to None in the case where a subclass defines them with eponymous methods.

bpo-38713 [https://bugs.python.org/issue?@action=redirect&bpo=38713]: Add os.P_PIDFD constant, which may be passed to os.waitid() to wait on a Linux process file descriptor.

bpo-38692 [https://bugs.python.org/issue?@action=redirect&bpo=38692]: Add asyncio.PidfdChildWatcher, a Linux-specific child watcher implementation that polls process file descriptors.

bpo-38692 [https://bugs.python.org/issue?@action=redirect&bpo=38692]: Expose the Linux pidfd_open syscall as os.pidfd_open().

bpo-38602 [https://bugs.python.org/issue?@action=redirect&bpo=38602]: Added constants F_OFD_GETLK, F_OFD_SETLK and F_OFD_SETLKW to the fcntl module. Patch by Donghee Na.

bpo-38334 [https://bugs.python.org/issue?@action=redirect&bpo=38334]: Fixed seeking backward on an encrypted zipfile.ZipExtFile.

bpo-38312 [https://bugs.python.org/issue?@action=redirect&bpo=38312]: Add curses.get_escdelay(), curses.set_escdelay(), curses.get_tabsize(), and curses.set_tabsize() functions - by Anthony Sottile.

bpo-38586 [https://bugs.python.org/issue?@action=redirect&bpo=38586]: Now fileConfig() correctly sets the .name of handlers loaded.

bpo-38565 [https://bugs.python.org/issue?@action=redirect&bpo=38565]: Add new cache_parameters() method for functools.lru_cache() to better support pickling.

bpo-34679 [https://bugs.python.org/issue?@action=redirect&bpo=34679]: asynci.ProactorEventLoop.close() now only calls signal.set_wakeup_fd() in the main thread.

bpo-31202 [https://bugs.python.org/issue?@action=redirect&bpo=31202]: The case the result of pathlib.WindowsPath.glob() matches now the case of the pattern for literal parts.

bpo-36321 [https://bugs.python.org/issue?@action=redirect&bpo=36321]: Remove misspelled attribute. The 3.8 changelog noted that this would be removed in 3.9.

bpo-38521 [https://bugs.python.org/issue?@action=redirect&bpo=38521]: Fixed erroneous equality comparison in statistics.NormalDist().

bpo-38493 [https://bugs.python.org/issue?@action=redirect&bpo=38493]: Added CLD_KILLED and CLD_STOPPED for si_code. Patch by Donghee Na.

bpo-38478 [https://bugs.python.org/issue?@action=redirect&bpo=38478]: Fixed a bug in inspect.signature.bind() that was causing it to fail when handling a keyword argument with same name as positional-only parameter. Patch by Pablo Galindo.

bpo-33604 [https://bugs.python.org/issue?@action=redirect&bpo=33604]: Fixed hmac.new and hmac.HMAC to raise TypeError instead of ValueError when the digestmod parameter, now required in 3.8, is omitted. Also clarified the hmac module documentation and docstrings.

bpo-38378 [https://bugs.python.org/issue?@action=redirect&bpo=38378]: Parameters out and in of os.sendfile() was renamed to out_fd and in_fd.

bpo-38417 [https://bugs.python.org/issue?@action=redirect&bpo=38417]: Added support for setting the umask in the child process to the subprocess module on POSIX systems.

bpo-38449 [https://bugs.python.org/issue?@action=redirect&bpo=38449]: Revert PR 15522, which introduces a regression in mimetypes.guess_type() due to improper handling of filenames as urls.

bpo-38431 [https://bugs.python.org/issue?@action=redirect&bpo=38431]: Fix __repr__ method for dataclasses.InitVar to support typing objects, patch by Samuel Colvin.

bpo-38109 [https://bugs.python.org/issue?@action=redirect&bpo=38109]: Add missing stat.S_IFDOOR, stat.S_IFPORT, stat.S_IFWHT, stat.S_ISDOOR(), stat.S_ISPORT(), and stat.S_ISWHT() values to the Python implementation of stat.

bpo-38422 [https://bugs.python.org/issue?@action=redirect&bpo=38422]: Clarify docstrings of pathlib suffix(es)

bpo-38405 [https://bugs.python.org/issue?@action=redirect&bpo=38405]: Nested subclasses of typing.NamedTuple are now pickleable.

bpo-38332 [https://bugs.python.org/issue?@action=redirect&bpo=38332]: Prevent KeyError thrown by _encoded_words.decode() when given an encoded-word with invalid content-type encoding from propagating all the way to email.message.get().

bpo-38371 [https://bugs.python.org/issue?@action=redirect&bpo=38371]: Deprecated the split() method in _tkinter.TkappType in favour of the splitlist() method which has more consistent and predictable behavior.

bpo-38341 [https://bugs.python.org/issue?@action=redirect&bpo=38341]: Add smtplib.SMTPNotSupportedError to the smtplib exported names.

bpo-38319 [https://bugs.python.org/issue?@action=redirect&bpo=38319]: sendfile() used in socket and shutil modules was raising OverflowError for files >= 2GiB on 32-bit architectures. (patch by Giampaolo Rodola)

bpo-38242 [https://bugs.python.org/issue?@action=redirect&bpo=38242]: Revert the new asyncio Streams API

bpo-13153 [https://bugs.python.org/issue?@action=redirect&bpo=13153]: OS native encoding is now used for converting between Python strings and Tcl objects. This allows to display, copy and paste to clipboard emoji and other non-BMP characters. Converting strings from Tcl to Python and back now never fails (except MemoryError).

bpo-38019 [https://bugs.python.org/issue?@action=redirect&bpo=38019]: Correctly handle pause/resume reading of closed asyncio unix pipe.

bpo-38163 [https://bugs.python.org/issue?@action=redirect&bpo=38163]: Child mocks will now detect their type as either synchronous or asynchronous, asynchronous child mocks will be AsyncMocks and synchronous child mocks will be either MagicMock or Mock (depending on their parent type).

bpo-38161 [https://bugs.python.org/issue?@action=redirect&bpo=38161]: Removes _AwaitEvent from AsyncMock.

bpo-38216 [https://bugs.python.org/issue?@action=redirect&bpo=38216]: Allow the rare code that wants to send invalid http requests from the http.client library a way to do so. The fixes for bpo-30458 [https://bugs.python.org/issue?@action=redirect&bpo=30458] led to breakage for some projects that were relying on this ability to test their own behavior in the face of bad requests.

bpo-28286 [https://bugs.python.org/issue?@action=redirect&bpo=28286]: Deprecate opening GzipFile for writing implicitly. Always specify the mode argument for writing.

bpo-38108 [https://bugs.python.org/issue?@action=redirect&bpo=38108]: Any synchronous magic methods on an AsyncMock now return a MagicMock. Any asynchronous magic methods on a MagicMock now return an AsyncMock.

bpo-38265 [https://bugs.python.org/issue?@action=redirect&bpo=38265]: Update the length parameter of os.pread() to accept Py_ssize_t instead of int.

bpo-38112 [https://bugs.python.org/issue?@action=redirect&bpo=38112]: compileall has a higher default recursion limit and new command-line arguments for path manipulation, symlinks handling, and multiple optimization levels.

bpo-38248 [https://bugs.python.org/issue?@action=redirect&bpo=38248]: asyncio: Fix inconsistent immediate Task cancellation

bpo-38237 [https://bugs.python.org/issue?@action=redirect&bpo=38237]: The arguments for the builtin pow function are more descriptive. They can now also be passed in as keywords.

bpo-34002 [https://bugs.python.org/issue?@action=redirect&bpo=34002]: Improve efficiency in parts of email package by changing while-pop to a for loop, using isdisjoint instead of set intersections.

bpo-38191 [https://bugs.python.org/issue?@action=redirect&bpo=38191]: Constructors of NamedTuple and TypedDict types now accept arbitrary keyword argument names, including “cls”, “self”, “typename”, “_typename”, “fields” and “_fields”.

bpo-38155 [https://bugs.python.org/issue?@action=redirect&bpo=38155]: Add __all__ to datetime. Patch by Tahia Khan.

bpo-38185 [https://bugs.python.org/issue?@action=redirect&bpo=38185]: Fixed case-insensitive string comparison in sqlite3.Row indexing.

bpo-38136 [https://bugs.python.org/issue?@action=redirect&bpo=38136]: Changes AsyncMock call count and await count to be two different counters. Now await count only counts when a coroutine has been awaited, not when it has been called, and vice-versa. Update the documentation around this.

bpo-37828 [https://bugs.python.org/issue?@action=redirect&bpo=37828]: Fix default mock name in unittest.mock.Mock.assert_called() exceptions. Patch by Abraham Toriz Cruz.

bpo-38175 [https://bugs.python.org/issue?@action=redirect&bpo=38175]: Fix a memory leak in comparison of sqlite3.Row objects.

bpo-33936 [https://bugs.python.org/issue?@action=redirect&bpo=33936]: _hashlib no longer calls obsolete OpenSSL initialization function with OpenSSL 1.1.0+.

bpo-34706 [https://bugs.python.org/issue?@action=redirect&bpo=34706]: Preserve subclassing in inspect.Signature.from_callable.

bpo-38153 [https://bugs.python.org/issue?@action=redirect&bpo=38153]: Names of hashing algorithms from OpenSSL are now normalized to follow Python’s naming conventions. For example OpenSSL uses sha3-512 instead of sha3_512 or blake2b512 instead of blake2b.

bpo-38115 [https://bugs.python.org/issue?@action=redirect&bpo=38115]: Fix a bug in dis.findlinestarts() where it would return invalid bytecode offsets. Document that a code object’s co_lnotab can contain invalid bytecode offsets.

bpo-38148 [https://bugs.python.org/issue?@action=redirect&bpo=38148]: Add slots to asyncio transport classes, which can reduce memory usage.

bpo-38142 [https://bugs.python.org/issue?@action=redirect&bpo=38142]: The _hashlib OpenSSL wrapper extension module is now PEP-384 compliant.

bpo-9216 [https://bugs.python.org/issue?@action=redirect&bpo=9216]: hashlib constructors now support usedforsecurity flag to signal that a hashing algorithm is not used in a security context.

bpo-36991 [https://bugs.python.org/issue?@action=redirect&bpo=36991]: Fixes a potential incorrect AttributeError exception escaping ZipFile.extract() in some unsupported input error situations.

bpo-38134 [https://bugs.python.org/issue?@action=redirect&bpo=38134]: Remove obsolete copy of PBKDF2_HMAC_fast. All supported OpenSSL versions contain a fast implementation.

bpo-38132 [https://bugs.python.org/issue?@action=redirect&bpo=38132]: The OpenSSL hashlib wrapper uses a simpler implementation. Several Macros and pointless caches are gone. The hash name now comes from OpenSSL’s EVP. The algorithm name stays the same, except it is now always lower case.

bpo-38008 [https://bugs.python.org/issue?@action=redirect&bpo=38008]: Fix parent class check in protocols to correctly identify the module that provides a builtin protocol, instead of assuming they all come from the collections.abc module

bpo-34037 [https://bugs.python.org/issue?@action=redirect&bpo=34037]: For asyncio, add a new coroutine loop.shutdown_default_executor(). The new coroutine provides an API to schedule an executor shutdown that waits on the threadpool to finish closing. Also, asyncio.run() has been updated to utilize the new coroutine. Patch by Kyle Stanley.

bpo-37405 [https://bugs.python.org/issue?@action=redirect&bpo=37405]: Fixed regression bug for socket.getsockname() for non-CAN_ISOTP AF_CAN address family sockets by returning a 1-tuple instead of string.

bpo-38121 [https://bugs.python.org/issue?@action=redirect&bpo=38121]: Update parameter names on functions in importlib.metadata matching the changes in the 0.22 release of importlib_metadata.

bpo-38110 [https://bugs.python.org/issue?@action=redirect&bpo=38110]: The os.closewalk() implementation now uses the libc fdwalk() API on platforms where it is available.

bpo-38093 [https://bugs.python.org/issue?@action=redirect&bpo=38093]: Fixes AsyncMock so it doesn’t crash when used with AsyncContextManagers or AsyncIterators.

bpo-37488 [https://bugs.python.org/issue?@action=redirect&bpo=37488]: Add warning to datetime.utctimetuple(), datetime.utcnow() and datetime.utcfromtimestamp() .

bpo-35640 [https://bugs.python.org/issue?@action=redirect&bpo=35640]: Allow passing a path-like object as directory argument to the http.server.SimpleHTTPRequestHandler class. Patch by Géry Ogam.

bpo-38086 [https://bugs.python.org/issue?@action=redirect&bpo=38086]: Update importlib.metadata with changes from importlib_metadata 0.21 [https://gitlab.com/python-devs/importlib_metadata/blob/0.21/importlib_metadata/docs/changelog.rst].

bpo-37251 [https://bugs.python.org/issue?@action=redirect&bpo=37251]: Remove __code__ check in AsyncMock that incorrectly evaluated function specs as async objects but failed to evaluate classes with __await__ but no __code__ attribute defined as async objects.

bpo-38037 [https://bugs.python.org/issue?@action=redirect&bpo=38037]: Fix reference counters in the signal module.

bpo-38066 [https://bugs.python.org/issue?@action=redirect&bpo=38066]: Hide internal asyncio.Stream methods: feed_eof(), feed_data(), set_exception() and set_transport().

bpo-38059 [https://bugs.python.org/issue?@action=redirect&bpo=38059]: inspect.py now uses sys.exit() instead of exit()

bpo-38049 [https://bugs.python.org/issue?@action=redirect&bpo=38049]: Added command-line interface for the ast module.

bpo-37953 [https://bugs.python.org/issue?@action=redirect&bpo=37953]: In typing, improved the __hash__ and __eq__ methods for ForwardReferences.

bpo-38026 [https://bugs.python.org/issue?@action=redirect&bpo=38026]: Fixed inspect.getattr_static() used isinstance while it should avoid dynamic lookup.

bpo-35923 [https://bugs.python.org/issue?@action=redirect&bpo=35923]: Update importlib.machinery.BuiltinImporter to use loader._ORIGIN instead of a hardcoded value. Patch by Donghee Na.

bpo-38010 [https://bugs.python.org/issue?@action=redirect&bpo=38010]: In importlib.metadata sync with importlib_metadata 0.20, clarifying behavior of files() and fixing issue where only one requirement was returned for requires() on dist-info packages.

bpo-38006 [https://bugs.python.org/issue?@action=redirect&bpo=38006]: weakref.WeakValueDictionary defines a local remove() function used as callback for weak references. This function was created with a closure. Modify the implementation to avoid the closure.

bpo-37995 [https://bugs.python.org/issue?@action=redirect&bpo=37995]: Added the indent option to ast.dump() which allows it to produce a multiline indented output.

bpo-34410 [https://bugs.python.org/issue?@action=redirect&bpo=34410]: Fixed a crash in the tee() iterator when re-enter it. RuntimeError is now raised in this case.

bpo-37140 [https://bugs.python.org/issue?@action=redirect&bpo=37140]: Fix a ctypes regression of Python 3.8. When a ctypes.Structure is passed by copy to a function, ctypes internals created a temporary object which had the side effect of calling the structure finalizer (__del__) twice. The Python semantics requires a finalizer to be called exactly once. Fix ctypes internals to no longer call the finalizer twice.

bpo-37587 [https://bugs.python.org/issue?@action=redirect&bpo=37587]: _json.scanstring is now up to 3x faster when there are many backslash escaped characters in the JSON string.

bpo-37834 [https://bugs.python.org/issue?@action=redirect&bpo=37834]: Prevent shutil.rmtree exception when built on non-Windows system without fd system call support, like older versions of macOS.

bpo-10978 [https://bugs.python.org/issue?@action=redirect&bpo=10978]: Semaphores and BoundedSemaphores can now release more than one waiting thread at a time.

bpo-37972 [https://bugs.python.org/issue?@action=redirect&bpo=37972]: Subscripts to the unittest.mock.call objects now receive the same chaining mechanism as any other custom attributes, so that the following usage no longer raises a TypeError:

call().foo().__getitem__('bar')

Patch by blhsing

bpo-37965 [https://bugs.python.org/issue?@action=redirect&bpo=37965]: Fix C compiler warning caused by distutils.ccompiler.CCompiler.has_function.

bpo-37964 [https://bugs.python.org/issue?@action=redirect&bpo=37964]: Add F_GETPATH command to fcntl.

bpo-37960 [https://bugs.python.org/issue?@action=redirect&bpo=37960]: repr() of buffered and text streams now silences only expected exceptions when get the value of “name” and “mode” attributes.

bpo-37961 [https://bugs.python.org/issue?@action=redirect&bpo=37961]: Add a total_nframe field to the traces collected by the tracemalloc module. This field indicates the original number of frames before it was truncated.

bpo-37951 [https://bugs.python.org/issue?@action=redirect&bpo=37951]: Most features of the subprocess module now work again in subinterpreters. Only preexec_fn is restricted in subinterpreters.

bpo-36205 [https://bugs.python.org/issue?@action=redirect&bpo=36205]: Fix the rusage implementation of time.process_time() to correctly report the sum of the system and user CPU time.

bpo-37950 [https://bugs.python.org/issue?@action=redirect&bpo=37950]: Fix ast.dump() when call with incompletely initialized node.

bpo-34679 [https://bugs.python.org/issue?@action=redirect&bpo=34679]: Restores instantiation of Windows IOCP event loops from the non-main thread.

bpo-36917 [https://bugs.python.org/issue?@action=redirect&bpo=36917]: Add default implementation of the ast.NodeVisitor.visit_Constant() method which emits a deprecation warning and calls corresponding methods visit_Num(), visit_Str(), etc.

bpo-37798 [https://bugs.python.org/issue?@action=redirect&bpo=37798]: Update test_statistics.py to verify that the statistics module works well for both C and Python implementations. Patch by Donghee Na

bpo-26589 [https://bugs.python.org/issue?@action=redirect&bpo=26589]: Added a new status code to the http module: 451 UNAVAILABLE_FOR_LEGAL_REASONS

bpo-37915 [https://bugs.python.org/issue?@action=redirect&bpo=37915]: Fix a segmentation fault that appeared when comparing instances of datetime.timezone and datetime.tzinfo objects. Patch by Pablo Galindo.

bpo-32554 [https://bugs.python.org/issue?@action=redirect&bpo=32554]: Deprecate having random.seed() call hash on arbitrary types.

bpo-9938 [https://bugs.python.org/issue?@action=redirect&bpo=9938]: Add optional keyword argument exit_on_error for ArgumentParser.

bpo-37851 [https://bugs.python.org/issue?@action=redirect&bpo=37851]: The faulthandler module no longer allocates its alternative stack at Python startup. Now the stack is only allocated at the first faulthandler usage.

bpo-32793 [https://bugs.python.org/issue?@action=redirect&bpo=32793]: Fix a duplicated debug message when smtplib.SMTP.connect() is called.

bpo-37885 [https://bugs.python.org/issue?@action=redirect&bpo=37885]: venv: Don’t generate unset variable warning on deactivate.

bpo-37868 [https://bugs.python.org/issue?@action=redirect&bpo=37868]: Fix dataclasses.is_dataclass when given an instance that never raises AttributeError in __getattr__. That is, an object that returns something for __dataclass_fields__ even if it’s not a dataclass.

bpo-37811 [https://bugs.python.org/issue?@action=redirect&bpo=37811]: Fix socket module’s socket.connect(address) function being unable to establish connection in case of interrupted system call. The problem was observed on all OSes which poll(2) system call can take only non-negative integers and -1 as a timeout value.

bpo-37863 [https://bugs.python.org/issue?@action=redirect&bpo=37863]: Optimizations for Fraction.__hash__ suggested by Tim Peters.

bpo-21131 [https://bugs.python.org/issue?@action=redirect&bpo=21131]: Fix faulthandler.register(chain=True) stack. faulthandler now allocates a dedicated stack of SIGSTKSZ*2 bytes, instead of just SIGSTKSZ bytes. Calling the previous signal handler in faulthandler signal handler uses more than SIGSTKSZ bytes of stack memory on some platforms.

bpo-37798 [https://bugs.python.org/issue?@action=redirect&bpo=37798]: Add C fastpath for statistics.NormalDist.inv_cdf() Patch by Donghee Na

bpo-37804 [https://bugs.python.org/issue?@action=redirect&bpo=37804]: Remove the deprecated method threading.Thread.isAlive(). Patch by Donghee Na.

bpo-37819 [https://bugs.python.org/issue?@action=redirect&bpo=37819]: Add Fraction.as_integer_ratio() to match the corresponding methods in bool, int, float, and decimal.

bpo-14465 [https://bugs.python.org/issue?@action=redirect&bpo=14465]: Add an xml.etree.ElementTree.indent() function for pretty-printing XML trees. Contributed by Stefan Behnel.

bpo-37810 [https://bugs.python.org/issue?@action=redirect&bpo=37810]: Fix difflib ? hint in diff output when dealing with tabs. Patch by Anthony Sottile.

bpo-37772 [https://bugs.python.org/issue?@action=redirect&bpo=37772]: In zipfile.Path, when adding implicit dirs, ensure that ancestral directories are added and that duplicates are excluded.

bpo-18578 [https://bugs.python.org/issue?@action=redirect&bpo=18578]: Renamed and documented test.bytecode_helper as test.support.bytecode_helper. Patch by Joannah Nanjekye.

bpo-37785 [https://bugs.python.org/issue?@action=redirect&bpo=37785]: Fix xgettext warnings in argparse.

bpo-34488 [https://bugs.python.org/issue?@action=redirect&bpo=34488]: writelines() method of io.BytesIO is now slightly faster when many small lines are passed. Patch by Sergey Fedoseev.

bpo-37449 [https://bugs.python.org/issue?@action=redirect&bpo=37449]: ensurepip now uses importlib.resources.read_binary() to read data instead of pkgutil.get_data(). Patch by Joannah Nanjekye.

bpo-28292 [https://bugs.python.org/issue?@action=redirect&bpo=28292]: Mark calendar.py helper functions as being private. The follows PEP 8 guidance to maintain the style conventions in the module and it addresses a known case of user confusion.

bpo-18049 [https://bugs.python.org/issue?@action=redirect&bpo=18049]: Add definition of THREAD_STACK_SIZE for AIX in Python/thread_pthread.h The default thread stacksize caused crashes with the default recursion limit Patch by M Felt

bpo-37742 [https://bugs.python.org/issue?@action=redirect&bpo=37742]: The logging.getLogger() API now returns the root logger when passed the name ‘root’, whereas previously it returned a non-root logger named ‘root’. This could affect cases where user code explicitly wants a non-root logger named ‘root’, or instantiates a logger using logging.getLogger(__name__) in some top-level module called ‘root.py’.

bpo-37738 [https://bugs.python.org/issue?@action=redirect&bpo=37738]: Fix the implementation of curses addch(str, color_pair): pass the color pair to setcchar(), instead of always passing 0 as the color pair.

bpo-37723 [https://bugs.python.org/issue?@action=redirect&bpo=37723]: Fix performance regression on regular expression parsing with huge character sets. Patch by Yann Vaginay.

bpo-35943 [https://bugs.python.org/issue?@action=redirect&bpo=35943]: The function PyImport_GetModule() now ensures any module it returns is fully initialized. Patch by Joannah Nanjekye.

bpo-32178 [https://bugs.python.org/issue?@action=redirect&bpo=32178]: Fix IndexError in email package when trying to parse invalid address fields starting with :.

bpo-37268 [https://bugs.python.org/issue?@action=redirect&bpo=37268]: The parser module is deprecated and will be removed in future versions of Python.

bpo-11953 [https://bugs.python.org/issue?@action=redirect&bpo=11953]: Completing WSA* error codes in socket.

bpo-37685 [https://bugs.python.org/issue?@action=redirect&bpo=37685]: Fixed comparisons of datetime.timedelta and datetime.timezone.

bpo-37697 [https://bugs.python.org/issue?@action=redirect&bpo=37697]: Synchronize importlib.metadata with importlib_metadata 0.19 [https://gitlab.com/python-devs/importlib_metadata/-/milestones/20], improving handling of EGG-INFO files and fixing a crash when entry point names contained colons.

bpo-37695 [https://bugs.python.org/issue?@action=redirect&bpo=37695]: Correct curses.unget_wch() error message. Patch by Anthony Sottile.

bpo-37689 [https://bugs.python.org/issue?@action=redirect&bpo=37689]: Add is_relative_to() in PurePath to determine whether or not one path is relative to another.

bpo-29553 [https://bugs.python.org/issue?@action=redirect&bpo=29553]: Fixed argparse.ArgumentParser.format_usage() for mutually exclusive groups. Patch by Andrew Nester.

bpo-37691 [https://bugs.python.org/issue?@action=redirect&bpo=37691]: Let math.dist() accept coordinates as sequences (or iterables) rather than just tuples.

bpo-37685 [https://bugs.python.org/issue?@action=redirect&bpo=37685]: Fixed __eq__, __lt__ etc implementations in some classes. They now return NotImplemented for unsupported type of the other operand. This allows the other operand to play role (for example the equality comparison with ANY will return True).

bpo-37354 [https://bugs.python.org/issue?@action=redirect&bpo=37354]: Make Activate.ps1 Powershell script static to allow for signing it.

bpo-37664 [https://bugs.python.org/issue?@action=redirect&bpo=37664]: Update wheels bundled with ensurepip (pip 19.2.3 and setuptools 41.2.0)

bpo-37663 [https://bugs.python.org/issue?@action=redirect&bpo=37663]: Bring consistency to venv shell activation scripts by always using __VENV_PROMPT__.

bpo-37642 [https://bugs.python.org/issue?@action=redirect&bpo=37642]: Allowed the pure Python implementation of datetime.timezone to represent sub-minute offsets close to minimum and maximum boundaries, specifically in the ranges (23:59, 24:00) and (-23:59, 24:00). Patch by Ngalim Siregar

bpo-36161 [https://bugs.python.org/issue?@action=redirect&bpo=36161]: In posix, use ttyname_r instead of ttyname for thread safety.

bpo-36324 [https://bugs.python.org/issue?@action=redirect&bpo=36324]: Make internal attributes for statistics.NormalDist() private.

bpo-37555 [https://bugs.python.org/issue?@action=redirect&bpo=37555]: Fix NonCallableMock._call_matcher returning tuple instead of _Call object when self._spec_signature exists. Patch by Elizabeth Uselton

bpo-29446 [https://bugs.python.org/issue?@action=redirect&bpo=29446]: Make from tkinter import * import only the expected objects.

bpo-16970 [https://bugs.python.org/issue?@action=redirect&bpo=16970]: Adding a value error when an invalid value in passed to nargs Patch by Robert Leenders

bpo-34443 [https://bugs.python.org/issue?@action=redirect&bpo=34443]: Exceptions from enum now use the __qualname of the enum class in the exception message instead of the __name__.

bpo-37491 [https://bugs.python.org/issue?@action=redirect&bpo=37491]: Fix IndexError when parsing email headers with unexpectedly ending bare-quoted string value. Patch by Abhilash Raj.

bpo-37587 [https://bugs.python.org/issue?@action=redirect&bpo=37587]: Make json.loads faster for long strings. (Patch by Marco Paolini)

bpo-18378 [https://bugs.python.org/issue?@action=redirect&bpo=18378]: Recognize “UTF-8” as a valid value for LC_CTYPE in locale._parse_localename.

bpo-37579 [https://bugs.python.org/issue?@action=redirect&bpo=37579]: Return NotImplemented in Python implementation of __eq__ for timedelta and time when the other object being compared is not of the same type to match C implementation. Patch by Karthikeyan Singaravelan.

bpo-21478 [https://bugs.python.org/issue?@action=redirect&bpo=21478]: Record calls to parent when autospecced object is attached to a mock using unittest.mock.attach_mock(). Patch by Karthikeyan Singaravelan.

bpo-37531 [https://bugs.python.org/issue?@action=redirect&bpo=37531]: “python3 -m test -jN –timeout=TIMEOUT” now kills a worker process if it runs longer than TIMEOUT seconds.

bpo-37482 [https://bugs.python.org/issue?@action=redirect&bpo=37482]: Fix serialization of display name in originator or destination address fields with both encoded words and special chars.

bpo-36993 [https://bugs.python.org/issue?@action=redirect&bpo=36993]: Improve error reporting for corrupt zip files with bad zip64 extra data. Patch by Daniel Hillier.

bpo-37502 [https://bugs.python.org/issue?@action=redirect&bpo=37502]: pickle.loads() no longer raises TypeError when the buffers argument is set to None

bpo-37520 [https://bugs.python.org/issue?@action=redirect&bpo=37520]: Correct behavior for zipfile.Path.parent when the path object identifies a subdirectory.

bpo-18374 [https://bugs.python.org/issue?@action=redirect&bpo=18374]: Fix the .col_offset attribute of nested ast.BinOp instances which had a too large value in some situations.

bpo-37424 [https://bugs.python.org/issue?@action=redirect&bpo=37424]: Fixes a possible hang when using a timeout on subprocess.run() while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: Fix multiprocessing.util.get_temp_dir() finalizer: clear also the ‘tempdir’ configuration of the current process, so next call to get_temp_dir() will create a new temporary directory, rather than reusing the removed temporary directory.

bpo-37481 [https://bugs.python.org/issue?@action=redirect&bpo=37481]: The distutils bdist_wininst command is deprecated in Python 3.8, use bdist_wheel (wheel packages) instead.

bpo-37479 [https://bugs.python.org/issue?@action=redirect&bpo=37479]: When Enum.__str__ is overridden in a derived class, the override will be used by Enum.__format__ regardless of whether mixin classes are present.

bpo-37440 [https://bugs.python.org/issue?@action=redirect&bpo=37440]: http.client now enables TLS 1.3 post-handshake authentication for default context or if a cert_file is passed to HTTPSConnection.

bpo-37437 [https://bugs.python.org/issue?@action=redirect&bpo=37437]: Update vendorized expat version to 2.2.7.

bpo-37428 [https://bugs.python.org/issue?@action=redirect&bpo=37428]: SSLContext.post_handshake_auth = True no longer sets SSL_VERIFY_POST_HANDSHAKE verify flag for client connections. Although the option is documented as ignored for clients, OpenSSL implicitly enables cert chain validation when the flag is set.

bpo-37420 [https://bugs.python.org/issue?@action=redirect&bpo=37420]: os.sched_setaffinity() now correctly handles errors that arise during iteration over its mask argument. Patch by Brandt Bucher.

bpo-37412 [https://bugs.python.org/issue?@action=redirect&bpo=37412]: The os.getcwdb() function now uses the UTF-8 encoding on Windows, rather than the ANSI code page: see PEP 529 [https://peps.python.org/pep-0529/] for the rationale. The function is no longer deprecated on Windows.

bpo-37406 [https://bugs.python.org/issue?@action=redirect&bpo=37406]: The sqlite3 module now raises TypeError, rather than ValueError, if operation argument type is not str: execute(), executemany() and calling a connection.

bpo-29412 [https://bugs.python.org/issue?@action=redirect&bpo=29412]: Fix IndexError in parsing a header value ending unexpectedly. Patch by Abhilash Raj.

bpo-36546 [https://bugs.python.org/issue?@action=redirect&bpo=36546]: The dist argument for statistics.quantiles() is now positional only. The current name doesn’t reflect that the argument can be either a dataset or a distribution. Marking the parameter as positional avoids confusion and makes it possible to change the name later.

bpo-37394 [https://bugs.python.org/issue?@action=redirect&bpo=37394]: Fix a bug that was causing the queue module to fail if the accelerator module was not available. Patch by Pablo Galindo.

bpo-37376 [https://bugs.python.org/issue?@action=redirect&bpo=37376]: pprint now has support for types.SimpleNamespace. Patch by Carl Bordum Hansen.

bpo-26967 [https://bugs.python.org/issue?@action=redirect&bpo=26967]: An ArgumentParser with allow_abbrev=False no longer disables grouping of short flags, such as -vv, but only disables abbreviation of long flags as documented. Patch by Zac Hatfield-Dodds.

bpo-37212 [https://bugs.python.org/issue?@action=redirect&bpo=37212]: unittest.mock.call() now preserves the order of keyword arguments in repr output. Patch by Karthikeyan Singaravelan.

bpo-37372 [https://bugs.python.org/issue?@action=redirect&bpo=37372]: Fix error unpickling datetime.time objects from Python 2 with seconds>=24. Patch by Justin Blanchard.

bpo-37345 [https://bugs.python.org/issue?@action=redirect&bpo=37345]: Add formal support for UDPLITE sockets. Support was present before, but it is now easier to detect support with hasattr(socket, 'IPPROTO_UDPLITE') and there are constants defined for each of the values needed: socket.IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV, and UDPLITE_RECV_CSCOV. Patch by Gabe Appleton.

bpo-37358 [https://bugs.python.org/issue?@action=redirect&bpo=37358]: Optimized functools.partial by using vectorcall.

bpo-37347 [https://bugs.python.org/issue?@action=redirect&bpo=37347]: sqlite3.Connection.create_aggregate(), sqlite3.Connection.create_function(), sqlite3.Connection.set_authorizer(), sqlite3.Connection.set_progress_handler() sqlite3.Connection.set_trace_callback() methods lead to segfaults if some of these methods are called twice with an equal object but not the same. Now callbacks are stored more carefully. Patch by Aleksandr Balezin.

bpo-37163 [https://bugs.python.org/issue?@action=redirect&bpo=37163]: The obj argument of dataclasses.replace() is positional-only now.

bpo-37085 [https://bugs.python.org/issue?@action=redirect&bpo=37085]: Add the optional Linux SocketCAN Broadcast Manager constants, used as flags to configure the BCM behaviour, in the socket module. Patch by Karl Ding.

bpo-37328 [https://bugs.python.org/issue?@action=redirect&bpo=37328]: HTMLParser.unescape is removed. It was undocumented and deprecated since Python 3.4.

bpo-37305 [https://bugs.python.org/issue?@action=redirect&bpo=37305]: Add .webmanifest -> application/manifest+json to list of recognized file types and content type headers

bpo-37320 [https://bugs.python.org/issue?@action=redirect&bpo=37320]: aifc.openfp() alias to aifc.open(), sunau.openfp() alias to sunau.open(), and wave.openfp() alias to wave.open() have been removed. They were deprecated since Python 3.7.

bpo-37315 [https://bugs.python.org/issue?@action=redirect&bpo=37315]: Deprecated accepting floats with integral value (like 5.0) in math.factorial().

bpo-37312 [https://bugs.python.org/issue?@action=redirect&bpo=37312]: _dummy_thread and dummy_threading modules have been removed. These modules were deprecated since Python 3.7 which requires threading support.

bpo-33972 [https://bugs.python.org/issue?@action=redirect&bpo=33972]: Email with single part but content-type set to multipart/* doesn’t raise AttributeError anymore.

bpo-37280 [https://bugs.python.org/issue?@action=redirect&bpo=37280]: Use threadpool for reading from file for sendfile fallback mode.

bpo-37279 [https://bugs.python.org/issue?@action=redirect&bpo=37279]: Fix asyncio sendfile support when sendfile sends extra data in fallback mode.

bpo-19865 [https://bugs.python.org/issue?@action=redirect&bpo=19865]: ctypes.create_unicode_buffer() now also supports non-BMP characters on platforms with 16-bit wchar_t (for example, Windows and AIX).

bpo-37266 [https://bugs.python.org/issue?@action=redirect&bpo=37266]: In a subinterpreter, spawning a daemon thread now raises an exception. Daemon threads were never supported in subinterpreters. Previously, the subinterpreter finalization crashed with a Python fatal error if a daemon thread was still running.

bpo-37210 [https://bugs.python.org/issue?@action=redirect&bpo=37210]: Allow pure Python implementation of pickle to work even when the C _pickle module is unavailable.

bpo-21872 [https://bugs.python.org/issue?@action=redirect&bpo=21872]: Fix lzma: module decompresses data incompletely. When decompressing a FORMAT_ALONE format file, and it doesn’t have the end marker, sometimes the last one to dozens bytes can’t be output. Patch by Ma Lin.

bpo-35922 [https://bugs.python.org/issue?@action=redirect&bpo=35922]: Fix RobotFileParser.crawl_delay() and RobotFileParser.request_rate() to return None rather than raise AttributeError when no relevant rule is defined in the robots.txt file. Patch by Rémi Lapeyre.

bpo-35766 [https://bugs.python.org/issue?@action=redirect&bpo=35766]: Change the format of feature_version to be a (major, minor) tuple.

bpo-36607 [https://bugs.python.org/issue?@action=redirect&bpo=36607]: Eliminate RuntimeError raised by asyncio.all_tasks() if internal tasks weak set is changed by another thread during iteration.

bpo-18748 [https://bugs.python.org/issue?@action=redirect&bpo=18748]: _pyio.IOBase destructor now does nothing if getting the closed attribute fails to better mimic _io.IOBase finalizer.

bpo-36402 [https://bugs.python.org/issue?@action=redirect&bpo=36402]: Fix a race condition at Python shutdown when waiting for threads. Wait until the Python thread state of all non-daemon threads get deleted (join all non-daemon threads), rather than just wait until non-daemon Python threads complete.

bpo-37206 [https://bugs.python.org/issue?@action=redirect&bpo=37206]: Default values which cannot be represented as Python objects no longer improperly represented as None in function signatures.

bpo-37111 [https://bugs.python.org/issue?@action=redirect&bpo=37111]: Added encoding and errors keyword parameters to logging.basicConfig.

bpo-12144 [https://bugs.python.org/issue?@action=redirect&bpo=12144]: Ensure cookies with expires attribute are handled in CookieJar.make_cookies().

bpo-34886 [https://bugs.python.org/issue?@action=redirect&bpo=34886]: Fix an unintended ValueError from subprocess.run() when checking for conflicting input and stdin or capture_output and stdout or stderr args when they were explicitly provided but with None values within a passed in **kwargs dict rather than as passed directly by name. Patch contributed by Rémi Lapeyre.

bpo-37173 [https://bugs.python.org/issue?@action=redirect&bpo=37173]: The exception message for inspect.getfile() now correctly reports the passed class rather than the builtins module.

bpo-37178 [https://bugs.python.org/issue?@action=redirect&bpo=37178]: Give math.perm() a one argument form that means the same as math.factorial().

bpo-37178 [https://bugs.python.org/issue?@action=redirect&bpo=37178]: For math.perm(n, k), let k default to n, giving the same result as factorial.

bpo-37165 [https://bugs.python.org/issue?@action=redirect&bpo=37165]: Converted _collections._count_elements to use the Argument Clinic.

bpo-34767 [https://bugs.python.org/issue?@action=redirect&bpo=34767]: Do not always create a collections.deque in asyncio.Lock.

bpo-37158 [https://bugs.python.org/issue?@action=redirect&bpo=37158]: Speed-up statistics.fmean() by switching from a function to a generator.

bpo-34282 [https://bugs.python.org/issue?@action=redirect&bpo=34282]: Remove Enum._convert method, deprecated in 3.8.

bpo-37150 [https://bugs.python.org/issue?@action=redirect&bpo=37150]: argparse._ActionsContainer.add_argument now throws error, if someone accidentally pass FileType class object instead of instance of FileType as type argument.

bpo-28724 [https://bugs.python.org/issue?@action=redirect&bpo=28724]: The socket module now has the socket.send_fds() and socket.recv.fds() methods. Contributed by Joannah Nanjekye, Shinya Okano and Victor Stinner.

bpo-35621 [https://bugs.python.org/issue?@action=redirect&bpo=35621]: Support running asyncio subprocesses when execution event loop in a thread on UNIX.

bpo-36520 [https://bugs.python.org/issue?@action=redirect&bpo=36520]: Lengthy email headers with UTF-8 characters are now properly encoded when they are folded. Patch by Jeffrey Kintscher.

bpo-30835 [https://bugs.python.org/issue?@action=redirect&bpo=30835]: Fixed a bug in email parsing where a message with invalid bytes in content-transfer-encoding of a multipart message can cause an AttributeError. Patch by Andrew Donnellan.

bpo-31163 [https://bugs.python.org/issue?@action=redirect&bpo=31163]: pathlib.Path instance’s rename and replace methods now return the new Path instance.

bpo-25068 [https://bugs.python.org/issue?@action=redirect&bpo=25068]: urllib.request.ProxyHandler now lowercases the keys of the passed dictionary.

bpo-26185 [https://bugs.python.org/issue?@action=redirect&bpo=26185]: Fix repr() on empty ZipInfo object. Patch by Mickaël Schoentgen.

bpo-21315 [https://bugs.python.org/issue?@action=redirect&bpo=21315]: Email headers containing RFC2047 encoded words are parsed despite the missing whitespace, and a defect registered. Also missing trailing whitespace after encoded words is now registered as a defect.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Port test_datetime to VxWorks: skip zoneinfo tests on VxWorks

bpo-35805 [https://bugs.python.org/issue?@action=redirect&bpo=35805]: Add parser for Message-ID header and add it to default HeaderRegistry. This should prevent folding of Message-ID using RFC 2048 encoded words.

bpo-36871 [https://bugs.python.org/issue?@action=redirect&bpo=36871]: Ensure method signature is used instead of constructor signature of a class while asserting mock object against method calls. Patch by Karthikeyan Singaravelan.

bpo-35070 [https://bugs.python.org/issue?@action=redirect&bpo=35070]: posix.getgrouplist() now works correctly when the user belongs to NGROUPS_MAX supplemental groups. Patch by Jeffrey Kintscher.

bpo-31783 [https://bugs.python.org/issue?@action=redirect&bpo=31783]: Fix race condition in ThreadPoolExecutor when worker threads are created during interpreter shutdown.

bpo-36582 [https://bugs.python.org/issue?@action=redirect&bpo=36582]: Fix UserString.encode() to correctly return bytes rather than a UserString instance.

bpo-32424 [https://bugs.python.org/issue?@action=redirect&bpo=32424]: Deprecate xml.etree.ElementTree.Element.copy() in favor of copy.copy().

Patch by Gordon P. Hemsley

bpo-36564 [https://bugs.python.org/issue?@action=redirect&bpo=36564]: Fix infinite loop in email header folding logic that would be triggered when an email policy’s max_line_length is not long enough to include the required markup and any values in the message. Patch by Paul Ganssle

bpo-36543 [https://bugs.python.org/issue?@action=redirect&bpo=36543]: Removed methods Element.getchildren(), Element.getiterator() and ElementTree.getiterator() and the xml.etree.cElementTree module.

bpo-36409 [https://bugs.python.org/issue?@action=redirect&bpo=36409]: Remove the old plistlib API deprecated in Python 3.4

bpo-36302 [https://bugs.python.org/issue?@action=redirect&bpo=36302]: distutils sorts source file lists so that Extension .so files build more reproducibly by default

bpo-36250 [https://bugs.python.org/issue?@action=redirect&bpo=36250]: Ignore ValueError from signal with interaction in non-main thread.

bpo-36046 [https://bugs.python.org/issue?@action=redirect&bpo=36046]: Added user, group and extra_groups parameters to the subprocess.Popen constructor. Patch by Patrick McLean.

bpo-32627 [https://bugs.python.org/issue?@action=redirect&bpo=32627]: Fix compile error when _uuid headers conflicting included.

bpo-35800 [https://bugs.python.org/issue?@action=redirect&bpo=35800]: Deprecate smtpd.MailmanProxy ready for future removal.

bpo-35168 [https://bugs.python.org/issue?@action=redirect&bpo=35168]: shlex.shlex.punctuation_chars is now a read-only property.

bpo-8538 [https://bugs.python.org/issue?@action=redirect&bpo=8538]: Add support for boolean actions like --foo and --no-foo to argparse. Patch contributed by Rémi Lapeyre.

bpo-20504 [https://bugs.python.org/issue?@action=redirect&bpo=20504]: Fixes a bug in cgi module when a multipart/form-data request has no Content-Length header.

bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988]: The abstract base classes in collections.abc no longer are exposed in the regular collections module.

bpo-11122 [https://bugs.python.org/issue?@action=redirect&bpo=11122]: Distutils won’t check for rpmbuild in specified paths only.

bpo-34775 [https://bugs.python.org/issue?@action=redirect&bpo=34775]: Division handling of PurePath now returns NotImplemented instead of raising a TypeError when passed something other than an instance of str or PurePath. Patch by Roger Aiudi.

bpo-34749 [https://bugs.python.org/issue?@action=redirect&bpo=34749]: binascii.a2b_base64() is now up to 2 times faster. Patch by Sergey Fedoseev.

bpo-34519 [https://bugs.python.org/issue?@action=redirect&bpo=34519]: Add additional aliases for HP Roman 8. Patch by Michael Osipov.

bpo-28009 [https://bugs.python.org/issue?@action=redirect&bpo=28009]: Fix uuid.getnode() on platforms with ‘.’ as MAC Addr delimiter as well fix for MAC Addr format that omits a leading 0 in MAC Addr values. Currently, AIX is the only know platform with these settings. Patch by Michael Felt.

bpo-30618 [https://bugs.python.org/issue?@action=redirect&bpo=30618]: Add readlink(). Patch by Girts Folkmanis.

bpo-32498 [https://bugs.python.org/issue?@action=redirect&bpo=32498]: Made urllib.parse.unquote() accept bytes in addition to strings. Patch by Stein Karlsen.

bpo-33348 [https://bugs.python.org/issue?@action=redirect&bpo=33348]: lib2to3 now recognizes expressions after * and ** like in f(*[] or []).

bpo-32689 [https://bugs.python.org/issue?@action=redirect&bpo=32689]: Update shutil.move() function to allow for Path objects to be used as source argument. Patch by Emily Morehouse and Maxwell “5.13b” McKinnon.

bpo-32820 [https://bugs.python.org/issue?@action=redirect&bpo=32820]: Added __format__ to IPv4 and IPv6 classes. Always outputs a fully zero-padded string. Supports b/x/n modifiers (bin/hex/native format). Native format for IPv4 is bin, native format for IPv6 is hex. Also supports ‘#’ and ‘_’ modifiers.

bpo-27657 [https://bugs.python.org/issue?@action=redirect&bpo=27657]: Fix urllib.parse.urlparse() with numeric paths. A string like “path:80” is no longer parsed as a path but as a scheme (“path”) and a path (“80”).

bpo-4963 [https://bugs.python.org/issue?@action=redirect&bpo=4963]: Fixed non-deterministic behavior related to mimetypes extension mapping and module reinitialization.

Documentation

bpo-21767 [https://bugs.python.org/issue?@action=redirect&bpo=21767]: Explicitly mention abc support in functools.singledispatch

bpo-38816 [https://bugs.python.org/issue?@action=redirect&bpo=38816]: Provides more details about the interaction between fork() and CPython’s runtime, focusing just on the C-API. This includes cautions about where fork() should and shouldn’t be called.

bpo-38351 [https://bugs.python.org/issue?@action=redirect&bpo=38351]: Modernize email examples from %-formatting to f-strings.

bpo-38778 [https://bugs.python.org/issue?@action=redirect&bpo=38778]: Document the fact that RuntimeError is raised if os.fork() is called in a subinterpreter.

bpo-38592 [https://bugs.python.org/issue?@action=redirect&bpo=38592]: Add Brazilian Portuguese to the language switcher at Python Documentation website.

bpo-38294 [https://bugs.python.org/issue?@action=redirect&bpo=38294]: Add list of no-longer-escaped chars to re.escape documentation

bpo-38053 [https://bugs.python.org/issue?@action=redirect&bpo=38053]: Modernized the plistlib documentation

bpo-26868 [https://bugs.python.org/issue?@action=redirect&bpo=26868]: Fix example usage of PyModule_AddObject() to properly handle errors.

bpo-36797 [https://bugs.python.org/issue?@action=redirect&bpo=36797]: Fix a dead link in the distutils API Reference.

bpo-37977 [https://bugs.python.org/issue?@action=redirect&bpo=37977]: Warn more strongly and clearly about pickle insecurity

bpo-37979 [https://bugs.python.org/issue?@action=redirect&bpo=37979]: Added a link to dateutil.parser.isoparse in the datetime.fromisoformat documentation. Patch by Paul Ganssle

bpo-12707 [https://bugs.python.org/issue?@action=redirect&bpo=12707]: Deprecate info(), geturl(), getcode() methods in favor of the headers, url, and status properties, respectively, for HTTPResponse and addinfourl. Also deprecate the code attribute of addinfourl in favor of the status attribute. Patch by Ashwin Ramaswami

bpo-37937 [https://bugs.python.org/issue?@action=redirect&bpo=37937]: Mention frame.f_trace in sys.settrace() docs.

bpo-37878 [https://bugs.python.org/issue?@action=redirect&bpo=37878]: Make PyThreadState_DeleteCurrent() Internal.

bpo-37759 [https://bugs.python.org/issue?@action=redirect&bpo=37759]: Beginning edits to Whatsnew 3.8

bpo-37726 [https://bugs.python.org/issue?@action=redirect&bpo=37726]: Stop recommending getopt in the tutorial for command line argument parsing and promote argparse.

bpo-32910 [https://bugs.python.org/issue?@action=redirect&bpo=32910]: Remove implementation-specific behaviour of how venv’s Deactivate works.

bpo-37256 [https://bugs.python.org/issue?@action=redirect&bpo=37256]: Fix wording of arguments for Request in urllib.request

bpo-37284 [https://bugs.python.org/issue?@action=redirect&bpo=37284]: Add a brief note to indicate that any new sys.implementation required attributes must go through the PEP process.

bpo-30088 [https://bugs.python.org/issue?@action=redirect&bpo=30088]: Documented that mailbox.Maildir constructor doesn’t attempt to verify the maildir folder layout correctness. Patch by Sviatoslav Sydorenko.

bpo-37521 [https://bugs.python.org/issue?@action=redirect&bpo=37521]: Fix importlib examples to insert any newly created modules via importlib.util.module_from_spec() immediately into sys.modules instead of after calling loader.exec_module().

Thanks to Benjamin Mintz for finding the bug.

bpo-37456 [https://bugs.python.org/issue?@action=redirect&bpo=37456]: Slash (‘/’) is now part of syntax.

bpo-37487 [https://bugs.python.org/issue?@action=redirect&bpo=37487]: Fix PyList_GetItem index description to include 0.

bpo-37149 [https://bugs.python.org/issue?@action=redirect&bpo=37149]: Replace the dead link to the Tkinter 8.5 reference by John Shipman, New Mexico Tech, with a link to the archive.org copy.

bpo-37478 [https://bugs.python.org/issue?@action=redirect&bpo=37478]: Added possible exceptions to the description of os.chdir().

bpo-34903 [https://bugs.python.org/issue?@action=redirect&bpo=34903]: Documented that in datetime.datetime.strptime(), the leading zero in some two-digit formats is optional. Patch by Mike Gleen.

bpo-36260 [https://bugs.python.org/issue?@action=redirect&bpo=36260]: Add decompression pitfalls to zipfile module documentation.

bpo-37004 [https://bugs.python.org/issue?@action=redirect&bpo=37004]: In the documentation for difflib, a note was added explicitly warning that the results of SequenceMatcher’s ratio method may depend on the order of the input strings.

bpo-36960 [https://bugs.python.org/issue?@action=redirect&bpo=36960]: Restructured the datetime docs in the interest of making them more user-friendly and improving readability. Patch by Brad Solomon.

bpo-36487 [https://bugs.python.org/issue?@action=redirect&bpo=36487]: Make C-API docs clear about what the “main” interpreter is.

bpo-23460 [https://bugs.python.org/issue?@action=redirect&bpo=23460]: The documentation for decimal string formatting using the :g specifier has been updated to reflect the correct exponential notation cutoff point. Original patch contributed by Tuomas Suutari.

bpo-35803 [https://bugs.python.org/issue?@action=redirect&bpo=35803]: Document and test that tempfile functions may accept a path-like object for the dir argument. Patch by Anthony Sottile.

bpo-33944 [https://bugs.python.org/issue?@action=redirect&bpo=33944]: Added a note about the intended use of code in .pth files.

bpo-34293 [https://bugs.python.org/issue?@action=redirect&bpo=34293]: Fix the Doc/Makefile regarding PAPER environment variable and PDF builds

bpo-25237 [https://bugs.python.org/issue?@action=redirect&bpo=25237]: Add documentation for tkinter modules

Tests

bpo-38614 [https://bugs.python.org/issue?@action=redirect&bpo=38614]: Fix test_communicate() of test_asyncio.test_subprocess: use support.LONG_TIMEOUT (5 minutes), instead of just 1 minute.

bpo-38614 [https://bugs.python.org/issue?@action=redirect&bpo=38614]: Add timeout constants to test.support: LOOPBACK_TIMEOUT, INTERNET_TIMEOUT, SHORT_TIMEOUT and LONG_TIMEOUT.

bpo-38502 [https://bugs.python.org/issue?@action=redirect&bpo=38502]: test.regrtest now uses process groups in the multiprocessing mode (-jN command line option) if process groups are available: if os.setsid() and os.killpg() functions are available.

bpo-35998 [https://bugs.python.org/issue?@action=redirect&bpo=35998]: Fix a race condition in test_asyncio.test_start_tls_server_1(). Previously, there was a race condition between the test main() function which replaces the protocol and the test ServerProto protocol which sends ANSWER once it gets HELLO. Now, only the test main() function is responsible to send data, ServerProto no longer sends data.

bpo-38470 [https://bugs.python.org/issue?@action=redirect&bpo=38470]: Fix test_compileall.test_compile_dir_maxlevels() on Windows without long path support: only create 3 subdirectories instead of between 20 and 100 subdirectories.

bpo-37531 [https://bugs.python.org/issue?@action=redirect&bpo=37531]: On timeout, regrtest no longer attempts to call popen.communicate() again: it can hang until all child processes using stdout and stderr pipes completes. Kill the worker process and ignores its output. Change also the faulthandler timeout of the main process from 1 minute to 5 minutes, for Python slowest buildbots.

bpo-38239 [https://bugs.python.org/issue?@action=redirect&bpo=38239]: Fix test_gdb for Link Time Optimization (LTO) builds.

bpo-38275 [https://bugs.python.org/issue?@action=redirect&bpo=38275]: test_ssl now handles disabled TLS/SSL versions better. OpenSSL’s crypto policy and run-time settings are recognized and tests for disabled versions are skipped. Tests also accept more TLS minimum_versions for platforms that override OpenSSL’s default with strict settings.

bpo-38271 [https://bugs.python.org/issue?@action=redirect&bpo=38271]: The private keys for test_ssl were encrypted with 3DES in traditional PKCS#5 format. 3DES and the digest algorithm of PKCS#5 are blocked by some strict crypto policies. Use PKCS#8 format with AES256 encryption instead.

bpo-38270 [https://bugs.python.org/issue?@action=redirect&bpo=38270]: test.support now has a helper function to check for availability of a hash digest function. Several tests are refactored avoid MD5 and use SHA256 instead. Other tests are marked to use MD5 and skipped when MD5 is disabled.

bpo-37123 [https://bugs.python.org/issue?@action=redirect&bpo=37123]: Multiprocessing test test_mymanager() now also expects -SIGTERM, not only exitcode 0. BaseManager._finalize_manager() sends SIGTERM to the manager process if it takes longer than 1 second to stop, which happens on slow buildbots.

bpo-38212 [https://bugs.python.org/issue?@action=redirect&bpo=38212]: Multiprocessing tests: increase test_queue_feeder_donot_stop_onexc() timeout from 1 to 60 seconds.

bpo-38117 [https://bugs.python.org/issue?@action=redirect&bpo=38117]: Test with OpenSSL 1.1.1d

bpo-38018 [https://bugs.python.org/issue?@action=redirect&bpo=38018]: Increase code coverage for multiprocessing.shared_memory.

bpo-37805 [https://bugs.python.org/issue?@action=redirect&bpo=37805]: Add tests for json.dump(…, skipkeys=True). Patch by Donghee Na.

bpo-37531 [https://bugs.python.org/issue?@action=redirect&bpo=37531]: Enhance regrtest multiprocess timeout: write a message when killing a worker process, catch popen.kill() and popen.wait() exceptions, put a timeout on the second call to popen.communicate().

bpo-37876 [https://bugs.python.org/issue?@action=redirect&bpo=37876]: Add tests for ROT-13 codec.

bpo-36833 [https://bugs.python.org/issue?@action=redirect&bpo=36833]: Added tests for PyDateTime_xxx_GET_xxx() macros of the C API of the datetime module. Patch by Joannah Nanjekye.

bpo-37558 [https://bugs.python.org/issue?@action=redirect&bpo=37558]: Fix test_shared_memory_cleaned_after_process_termination name handling

bpo-37526 [https://bugs.python.org/issue?@action=redirect&bpo=37526]: Add test.support.catch_threading_exception(): context manager catching threading.Thread exception using threading.excepthook().

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: test_concurrent_futures now explicitly stops the ForkServer instance if it’s running.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: multiprocessing tests now stop the ForkServer instance if it’s running: close the “alive” file descriptor to ask the server to stop and then remove its UNIX address.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: test_distutils.test_build_ext() is now able to remove the temporary directory on Windows: don’t import the newly built C extension (“xx”) in the current process, but test it in a separated process.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: test_concurrent_futures now cleans up multiprocessing to remove immediately temporary directories created by multiprocessing.util.get_temp_dir().

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: test_winconsoleio doesn’t leak a temporary file anymore: use tempfile.TemporaryFile() to remove it when the test completes.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: multiprocessing tests now explicitly call _run_finalizers() to immediately remove temporary directories created by tests.

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: urllib.request tests now call urlcleanup() to remove temporary files created by urlretrieve() tests and to clear the _opener global variable set by urlopen() and functions calling indirectly urlopen().

bpo-37472 [https://bugs.python.org/issue?@action=redirect&bpo=37472]: Remove Lib/test/outstanding_bugs.py.

bpo-37199 [https://bugs.python.org/issue?@action=redirect&bpo=37199]: Fix test failures when IPv6 is unavailable or disabled.

bpo-19696 [https://bugs.python.org/issue?@action=redirect&bpo=19696]: Replace deprecated method “random.choose” with “random.choice” in “test_pkg_import.py”.

bpo-37335 [https://bugs.python.org/issue?@action=redirect&bpo=37335]: Remove no longer necessary code from c locale coercion tests

bpo-37421 [https://bugs.python.org/issue?@action=redirect&bpo=37421]: Fix test_shutil to no longer leak temporary files.

bpo-37411 [https://bugs.python.org/issue?@action=redirect&bpo=37411]: Fix test_wsgiref.testEnviron() to no longer depend on the environment variables (don’t fail if “X” variable is set).

bpo-37400 [https://bugs.python.org/issue?@action=redirect&bpo=37400]: Fix test_os.test_chown(): use os.getgroups() rather than grp.getgrall() to get groups. Rename also the test to test_chown_gid().

bpo-37359 [https://bugs.python.org/issue?@action=redirect&bpo=37359]: Add –cleanup option to python3 -m test to remove test_python_* directories of previous failed jobs. Add “make cleantest” to run python3 -m test --cleanup.

bpo-37362 [https://bugs.python.org/issue?@action=redirect&bpo=37362]: test_gdb no longer fails if it gets an “unexpected” message on stderr: it now ignores stderr. The purpose of test_gdb is to test that python-gdb.py commands work as expected, not to test gdb.

bpo-35998 [https://bugs.python.org/issue?@action=redirect&bpo=35998]: Avoid TimeoutError in test_asyncio: test_start_tls_server_1()

bpo-37278 [https://bugs.python.org/issue?@action=redirect&bpo=37278]: Fix test_asyncio ProactorLoopCtrlC: join the thread to prevent leaking a running thread and leaking a reference.

bpo-37261 [https://bugs.python.org/issue?@action=redirect&bpo=37261]: Fix test.support.catch_unraisable_exception(): its __exit__() method now ignores unraisable exception raised when clearing its unraisable attribute.

bpo-37069 [https://bugs.python.org/issue?@action=redirect&bpo=37069]: regrtest now uses sys.unraisablehook() to mark a test as “environment altered” (ENV_CHANGED) if it emits an “unraisable exception”. Moreover, regrtest logs a warning in this case.

Use python3 -m test --fail-env-changed to catch unraisable exceptions in tests.

bpo-37252 [https://bugs.python.org/issue?@action=redirect&bpo=37252]: Fix assertions in test_close and test_events_mask_overflow devpoll tests.

bpo-37169 [https://bugs.python.org/issue?@action=redirect&bpo=37169]: Rewrite _PyObject_IsFreed() unit tests.

bpo-37153 [https://bugs.python.org/issue?@action=redirect&bpo=37153]: test_venv.test_multiprocessing() now explicitly calls pool.terminate() to wait until the pool completes.

bpo-34001 [https://bugs.python.org/issue?@action=redirect&bpo=34001]: Make test_ssl pass with LibreSSL. LibreSSL handles minimum and maximum TLS version differently than OpenSSL.

bpo-36919 [https://bugs.python.org/issue?@action=redirect&bpo=36919]: Make test_source_encoding.test_issue2301 implementation independent. The test will work now for both CPython and IronPython.

bpo-30202 [https://bugs.python.org/issue?@action=redirect&bpo=30202]: Update test.test_importlib.test_abc to test find_spec().

bpo-28009 [https://bugs.python.org/issue?@action=redirect&bpo=28009]: Modify the test_uuid logic to test when a program is available AND can be used to obtain a MACADDR as basis for an UUID. Patch by M. Felt

bpo-34596 [https://bugs.python.org/issue?@action=redirect&bpo=34596]: Fallback to a default reason when unittest.skip() is uncalled. Patch by Naitree Zhu.

Build

bpo-38809 [https://bugs.python.org/issue?@action=redirect&bpo=38809]: On Windows, build scripts will now recognize and use python.exe from an active virtual env.

bpo-38684 [https://bugs.python.org/issue?@action=redirect&bpo=38684]: Fix _hashlib build when Blake2 is disabled, but OpenSSL supports it.

bpo-38468 [https://bugs.python.org/issue?@action=redirect&bpo=38468]: Misc/python-config.in now uses getvar() for all still existing sysconfig.get_config_var() calls. Patch by Joannah Nanjekye.

bpo-37415 [https://bugs.python.org/issue?@action=redirect&bpo=37415]: Fix stdatomic.h header check for ICC compiler: the ICC implementation lacks atomic_uintptr_t type which is needed by Python.

bpo-38301 [https://bugs.python.org/issue?@action=redirect&bpo=38301]: In Solaris family, we must be sure to use -D_REENTRANT. Patch by Jesús Cea Avión.

bpo-36002 [https://bugs.python.org/issue?@action=redirect&bpo=36002]: Locate llvm-profdata and llvm-ar binaries using AC_PATH_TOOL rather than AC_PATH_TARGET_TOOL.

bpo-37936 [https://bugs.python.org/issue?@action=redirect&bpo=37936]: The .gitignore file systematically keeps “rooted”, with a non-trailing slash, all the rules that are meant to apply to files in a specific place in the repo. Previously, when the intended file to ignore happened to be at the root of the repo, we’d most often accidentally also ignore files and directories with the same name anywhere in the tree.

bpo-37760 [https://bugs.python.org/issue?@action=redirect&bpo=37760]: The Tools/unicode/makeunicodedata.py script, which is used for converting information from the Unicode Character Database into generated code and data used by the methods of str and by the unicodedata module, now handles each character’s data as a dataclass with named attributes, rather than a length-18 list of different fields.

bpo-37936 [https://bugs.python.org/issue?@action=redirect&bpo=37936]: The .gitignore file no longer applies to any files that are in fact tracked in the Git repository. Patch by Greg Price.

bpo-37725 [https://bugs.python.org/issue?@action=redirect&bpo=37725]: Change “clean” makefile target to also clean the program guided optimization (PGO) data. Previously you would have to use “make clean” and “make profile-removal”, or “make clobber”.

bpo-37707 [https://bugs.python.org/issue?@action=redirect&bpo=37707]: Mark some individual tests to skip when –pgo is used. The tests marked increase the PGO task time significantly and likely don’t help improve optimization of the final executable.

bpo-36044 [https://bugs.python.org/issue?@action=redirect&bpo=36044]: Reduce the number of unit tests run for the PGO generation task. This speeds up the task by a factor of about 15x. Running the full unit test suite is slow. This change may result in a slightly less optimized build since not as many code branches will be executed. If you are willing to wait for the much slower build, the old behavior can be restored using ‘./configure [..] PROFILE_TASK=”-m test –pgo-extended”’. We make no guarantees as to which PGO task set produces a faster build. Users who care should run their own relevant benchmarks as results can depend on the environment, workload, and compiler tool chain.

bpo-37468 [https://bugs.python.org/issue?@action=redirect&bpo=37468]: make install no longer installs wininst-*.exe files used by distutils bdist_wininst: bdist_wininst only works on Windows.

bpo-37189 [https://bugs.python.org/issue?@action=redirect&bpo=37189]: Many PyRun_XXX() functions like PyRun_String() were no longer exported in libpython38.dll by mistake. Export them again to fix the ABI compatibility.

bpo-25361 [https://bugs.python.org/issue?@action=redirect&bpo=25361]: Enables use of SSE2 instructions in Windows 32-bit build.

bpo-36210 [https://bugs.python.org/issue?@action=redirect&bpo=36210]: Update optional extension module detection for AIX. ossaudiodev and spwd are not applicable for AIX, and are no longer reported as missing. 3rd-party packaging of ncurses (with ASIS support) conflicts with officially supported AIX curses library, so configure AIX to use libcurses.a. However, skip trying to build _curses_panel.

patch by M Felt

Windows

bpo-38589 [https://bugs.python.org/issue?@action=redirect&bpo=38589]: Fixes HTML Help shortcut when Windows is not installed to C drive

bpo-38453 [https://bugs.python.org/issue?@action=redirect&bpo=38453]: Ensure ntpath.realpath() correctly resolves relative paths.

bpo-38519 [https://bugs.python.org/issue?@action=redirect&bpo=38519]: Restores the internal C headers that were missing from the nuget.org and Microsoft Store packages.

bpo-38492 [https://bugs.python.org/issue?@action=redirect&bpo=38492]: Remove pythonw.exe dependency on the Microsoft C++ runtime.

bpo-38344 [https://bugs.python.org/issue?@action=redirect&bpo=38344]: Fix error message in activate.bat

bpo-38359 [https://bugs.python.org/issue?@action=redirect&bpo=38359]: Ensures pyw.exe launcher reads correct registry key.

bpo-38355 [https://bugs.python.org/issue?@action=redirect&bpo=38355]: Fixes ntpath.realpath failing on sys.executable.

bpo-38117 [https://bugs.python.org/issue?@action=redirect&bpo=38117]: Update bundled OpenSSL to 1.1.1d

bpo-38092 [https://bugs.python.org/issue?@action=redirect&bpo=38092]: Reduce overhead when using multiprocessing in a Windows virtual environment.

bpo-38133 [https://bugs.python.org/issue?@action=redirect&bpo=38133]: Allow py.exe launcher to locate installations from the Microsoft Store and improve display of active virtual environments.

bpo-38114 [https://bugs.python.org/issue?@action=redirect&bpo=38114]: The pip.ini is no longer included in the Nuget package.

bpo-32592 [https://bugs.python.org/issue?@action=redirect&bpo=32592]: Set Windows 8 as the minimum required version for API support

bpo-36634 [https://bugs.python.org/issue?@action=redirect&bpo=36634]: os.cpu_count() now returns active processors rather than maximum processors.

bpo-36634 [https://bugs.python.org/issue?@action=redirect&bpo=36634]: venv activate.bat now works when the existing variables contain double quote characters.

bpo-38081 [https://bugs.python.org/issue?@action=redirect&bpo=38081]: Prevent error calling os.path.realpath() on 'NUL'.

bpo-38087 [https://bugs.python.org/issue?@action=redirect&bpo=38087]: Fix case sensitivity in test_pathlib and test_ntpath.

bpo-38088 [https://bugs.python.org/issue?@action=redirect&bpo=38088]: Fixes distutils not finding vcruntime140.dll with only the v142 toolset installed.

bpo-37283 [https://bugs.python.org/issue?@action=redirect&bpo=37283]: Ensure command-line and unattend.xml setting override previously detected states in Windows installer.

bpo-38030 [https://bugs.python.org/issue?@action=redirect&bpo=38030]: Fixes os.stat() failing for block devices on Windows

bpo-38020 [https://bugs.python.org/issue?@action=redirect&bpo=38020]: Fixes potential crash when calling os.readlink() (or indirectly through realpath()) on a file that is not a supported link.

bpo-37705 [https://bugs.python.org/issue?@action=redirect&bpo=37705]: Improve the implementation of winerror_to_errno().

bpo-37549 [https://bugs.python.org/issue?@action=redirect&bpo=37549]: os.dup() no longer fails for standard streams on Windows 7.

bpo-1311 [https://bugs.python.org/issue?@action=redirect&bpo=1311]: The nul file on Windows now returns True from exists() and a valid result from os.stat() with S_IFCHR set.

bpo-9949 [https://bugs.python.org/issue?@action=redirect&bpo=9949]: Enable support for following symlinks in os.realpath().

bpo-37834 [https://bugs.python.org/issue?@action=redirect&bpo=37834]: Treat all name surrogate reparse points on Windows in os.lstat() and other reparse points as regular files in os.stat().

bpo-36266 [https://bugs.python.org/issue?@action=redirect&bpo=36266]: Add the module name in the formatted error message when DLL load fail happens during module import in _PyImport_FindSharedFuncptrWindows(). Patch by Srinivas Nyayapati.

bpo-25172 [https://bugs.python.org/issue?@action=redirect&bpo=25172]: Trying to import the crypt module on Windows will result in an ImportError with a message explaining that the module isn’t supported on Windows. On other platforms, if the underlying _crypt module is not available, the ImportError will include a message explaining the problem.

bpo-37778 [https://bugs.python.org/issue?@action=redirect&bpo=37778]: Fixes the icons used for file associations to the Microsoft Store package.

bpo-37734 [https://bugs.python.org/issue?@action=redirect&bpo=37734]: Fix use of registry values to launch Python from Microsoft Store app.

bpo-37702 [https://bugs.python.org/issue?@action=redirect&bpo=37702]: Fix memory leak on Windows in creating an SSLContext object or running urllib.request.urlopen('https://...').

bpo-37672 [https://bugs.python.org/issue?@action=redirect&bpo=37672]: Switch Windows Store package’s pip to use bundled pip.ini instead of PIP_USER variable.

bpo-10945 [https://bugs.python.org/issue?@action=redirect&bpo=10945]: Officially drop support for creating bdist_wininst installers on non-Windows systems.

bpo-37445 [https://bugs.python.org/issue?@action=redirect&bpo=37445]: Include the FORMAT_MESSAGE_IGNORE_INSERTS flag in FormatMessageW() calls.

bpo-37369 [https://bugs.python.org/issue?@action=redirect&bpo=37369]: Fixes path for sys.executable when running from the Microsoft Store.

bpo-37380 [https://bugs.python.org/issue?@action=redirect&bpo=37380]: Don’t collect unfinished processes with subprocess._active on Windows to cleanup later. Patch by Ruslan Kuprieiev.

bpo-37351 [https://bugs.python.org/issue?@action=redirect&bpo=37351]: Removes libpython38.a from standard Windows distribution.

bpo-35360 [https://bugs.python.org/issue?@action=redirect&bpo=35360]: Update Windows builds to use SQLite 3.28.0.

bpo-37267 [https://bugs.python.org/issue?@action=redirect&bpo=37267]: On Windows, os.dup() no longer creates an inheritable fd when handling a character file.

bpo-36779 [https://bugs.python.org/issue?@action=redirect&bpo=36779]: Ensure time.tzname is correct on Windows when the active code page is set to CP_UTF7 or CP_UTF8.

bpo-32587 [https://bugs.python.org/issue?@action=redirect&bpo=32587]: Make winreg.REG_MULTI_SZ support zero-length strings.

bpo-28269 [https://bugs.python.org/issue?@action=redirect&bpo=28269]: Replace use of strcasecmp() for the system function _stricmp(). Patch by Minmin Gong.

bpo-36590 [https://bugs.python.org/issue?@action=redirect&bpo=36590]: Add native Bluetooth RFCOMM support to socket module.

macOS

bpo-38117 [https://bugs.python.org/issue?@action=redirect&bpo=38117]: Updated OpenSSL to 1.1.1d in macOS installer.

bpo-38089 [https://bugs.python.org/issue?@action=redirect&bpo=38089]: Move Azure Pipelines to latest VM versions and make macOS tests optional

bpo-18049 [https://bugs.python.org/issue?@action=redirect&bpo=18049]: Increase the default stack size of threads from 5MB to 16MB on macOS, to match the stack size of the main thread. This avoids crashes on deep recursion in threads.

bpo-34602 [https://bugs.python.org/issue?@action=redirect&bpo=34602]: Avoid test suite failures on macOS by no longer calling resource.setrlimit to increase the process stack size limit at runtime. The runtime change is no longer needed since the interpreter is being built with a larger default stack size.

bpo-35360 [https://bugs.python.org/issue?@action=redirect&bpo=35360]: Update macOS installer to use SQLite 3.28.0.

bpo-34631 [https://bugs.python.org/issue?@action=redirect&bpo=34631]: Updated OpenSSL to 1.1.1c in macOS installer.

IDLE

bpo-26353 [https://bugs.python.org/issue?@action=redirect&bpo=26353]: Stop adding newline when saving an IDLE shell window.

bpo-4630 [https://bugs.python.org/issue?@action=redirect&bpo=4630]: Add an option to toggle IDLE’s cursor blink for shell, editor, and output windows. See Settings, General, Window Preferences, Cursor Blink. Patch by Zackery Spytz.

bpo-38598 [https://bugs.python.org/issue?@action=redirect&bpo=38598]: Do not try to compile IDLE shell or output windows

bpo-36698 [https://bugs.python.org/issue?@action=redirect&bpo=36698]: IDLE no longer fails when write non-encodable characters to stderr. It now escapes them with a backslash, as the regular Python interpreter. Added the errors field to the standard streams.

bpo-35379 [https://bugs.python.org/issue?@action=redirect&bpo=35379]: When exiting IDLE, catch any AttributeError. One happens when EditorWindow.close is called twice. Printing a traceback, when IDLE is run from a terminal, is useless and annoying.

bpo-38183 [https://bugs.python.org/issue?@action=redirect&bpo=38183]: To avoid problems, test_idle ignores the user config directory. It no longer tries to create or access .idlerc or any files within. Users must run IDLE to discover problems with saving settings.

bpo-38077 [https://bugs.python.org/issue?@action=redirect&bpo=38077]: IDLE no longer adds ‘argv’ to the user namespace when initializing it. This bug only affected 3.7.4 and 3.8.0b2 to 3.8.0b4.

bpo-38041 [https://bugs.python.org/issue?@action=redirect&bpo=38041]: Shell restart lines now fill the window width, always start with ‘=’, and avoid wrapping unnecessarily. The line will still wrap if the included file name is long relative to the width.

bpo-35771 [https://bugs.python.org/issue?@action=redirect&bpo=35771]: To avoid occasional spurious test_idle failures on slower machines, increase the hover_delay in test_tooltip.

bpo-37824 [https://bugs.python.org/issue?@action=redirect&bpo=37824]: Properly handle user input warnings in IDLE shell. Cease turning SyntaxWarnings into SyntaxErrors.

bpo-37929 [https://bugs.python.org/issue?@action=redirect&bpo=37929]: IDLE Settings dialog now closes properly when there is no shell window.

bpo-37902 [https://bugs.python.org/issue?@action=redirect&bpo=37902]: Add mousewheel scrolling for IDLE module, path, and stack browsers. Patch by George Zhang.

bpo-37849 [https://bugs.python.org/issue?@action=redirect&bpo=37849]: Fixed completions list appearing too high or low when shown above the current line.

bpo-36419 [https://bugs.python.org/issue?@action=redirect&bpo=36419]: Refactor IDLE autocomplete and improve testing.

bpo-37748 [https://bugs.python.org/issue?@action=redirect&bpo=37748]: Reorder the Run menu. Put the most common choice, Run Module, at the top.

bpo-37692 [https://bugs.python.org/issue?@action=redirect&bpo=37692]: Improve highlight config sample with example shell interaction and better labels for shell elements.

bpo-37628 [https://bugs.python.org/issue?@action=redirect&bpo=37628]: Settings dialog no longer expands with font size.

bpo-37627 [https://bugs.python.org/issue?@action=redirect&bpo=37627]: Initialize the Customize Run dialog with the command line arguments most recently entered before. The user can optionally edit before submitting them.

bpo-33610 [https://bugs.python.org/issue?@action=redirect&bpo=33610]: Fix code context not showing the correct context when first toggled on.

bpo-37530 [https://bugs.python.org/issue?@action=redirect&bpo=37530]: Optimize code context to reduce unneeded background activity. Font and highlight changes now occur along with text changes instead of after a random delay.

bpo-27452 [https://bugs.python.org/issue?@action=redirect&bpo=27452]: Cleanup config.py by inlining RemoveFile and simplifying the handling of file in CreateConfigHandlers.

bpo-37325 [https://bugs.python.org/issue?@action=redirect&bpo=37325]: Fix tab focus traversal order for help source and custom run dialogs.

bpo-37321 [https://bugs.python.org/issue?@action=redirect&bpo=37321]: Both subprocess connection error messages now refer to the ‘Startup failure’ section of the IDLE doc.

bpo-17535 [https://bugs.python.org/issue?@action=redirect&bpo=17535]: Add optional line numbers for IDLE editor windows. Windows open without line numbers unless set otherwise in the General tab of the configuration dialog.

bpo-26806 [https://bugs.python.org/issue?@action=redirect&bpo=26806]: To compensate for stack frames added by IDLE and avoid possible problems with low recursion limits, add 30 to limits in the user code execution process. Subtract 30 when reporting recursion limits to make this addition mostly transparent.

bpo-37177 [https://bugs.python.org/issue?@action=redirect&bpo=37177]: Properly ‘attach’ search dialogs to their main window so that they behave like other dialogs and do not get hidden behind their main window.

bpo-37039 [https://bugs.python.org/issue?@action=redirect&bpo=37039]: Adjust “Zoom Height” to individual screens by momentarily maximizing the window on first use with a particular screen. Changing screen settings may invalidate the saved height. While a window is maximized, “Zoom Height” has no effect.

bpo-35763 [https://bugs.python.org/issue?@action=redirect&bpo=35763]: Make calltip reminder about ‘/’ meaning positional-only less obtrusive by only adding it when there is room on the first line.

bpo-5680 [https://bugs.python.org/issue?@action=redirect&bpo=5680]: Add ‘Run… Customized’ to the Run menu to run a module with customized settings. Any ‘command line arguments’ entered are added to sys.argv. One can suppress the normal Shell main module restart.

bpo-36390 [https://bugs.python.org/issue?@action=redirect&bpo=36390]: Gather Format menu functions into format.py. Combine paragraph.py, rstrip.py, and format methods from editor.py.

Tools/Demos

bpo-38118 [https://bugs.python.org/issue?@action=redirect&bpo=38118]: Update Valgrind suppression file to ignore a false alarm in PyUnicode_Decode() when using GCC builtin strcmp().

bpo-38347 [https://bugs.python.org/issue?@action=redirect&bpo=38347]: pathfix.py: Assume all files that end on ‘.py’ are Python scripts when working recursively.

bpo-37803 [https://bugs.python.org/issue?@action=redirect&bpo=37803]: pdb’s --help and --version long options now work.

bpo-37942 [https://bugs.python.org/issue?@action=redirect&bpo=37942]: Improve ArgumentClinic converter for floats.

bpo-37704 [https://bugs.python.org/issue?@action=redirect&bpo=37704]: Remove Tools/scripts/h2py.py: use cffi to access a C API in Python.

bpo-37675 [https://bugs.python.org/issue?@action=redirect&bpo=37675]: 2to3 now works when run from a zipped standard library.

bpo-37034 [https://bugs.python.org/issue?@action=redirect&bpo=37034]: Argument Clinic now uses the argument name on errors with keyword-only argument instead of their position. Patch contributed by Rémi Lapeyre.

bpo-37064 [https://bugs.python.org/issue?@action=redirect&bpo=37064]: Add option -k to pathscript.py script: preserve shebang flags. Add option -a to pathscript.py script: add flags.

C API

bpo-37633 [https://bugs.python.org/issue?@action=redirect&bpo=37633]: Re-export some function compatibility wrappers for macros in pythonrun.h.

bpo-38644 [https://bugs.python.org/issue?@action=redirect&bpo=38644]: Provide Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() as regular functions for the limited API. Previously, there were defined as macros, but these macros didn’t work with the limited API which cannot access PyThreadState.recursion_depth field. Remove _Py_CheckRecursionLimit from the stable ABI.

bpo-38650 [https://bugs.python.org/issue?@action=redirect&bpo=38650]: The global variable PyStructSequence_UnnamedField is now a constant and refers to a constant string.

bpo-38540 [https://bugs.python.org/issue?@action=redirect&bpo=38540]: Fixed possible leak in PyArg_Parse() and similar functions for format units "es#" and "et#" when the macro PY_SSIZE_T_CLEAN is not defined.

bpo-38395 [https://bugs.python.org/issue?@action=redirect&bpo=38395]: Fix a crash in weakref.proxy objects due to incorrect lifetime management when calling some associated methods that may delete the last reference to object being referenced by the proxy. Patch by Pablo Galindo.

bpo-36389 [https://bugs.python.org/issue?@action=redirect&bpo=36389]: The _PyObject_CheckConsistency() function is now also available in release mode. For example, it can be used to debug a crash in the visit_decref() function of the GC.

bpo-38266 [https://bugs.python.org/issue?@action=redirect&bpo=38266]: Revert the removal of PyThreadState_DeleteCurrent() with documentation.

bpo-38303 [https://bugs.python.org/issue?@action=redirect&bpo=38303]: Update audioop extension module to use the stable ABI (PEP-384). Patch by Tyler Kieft.

bpo-38234 [https://bugs.python.org/issue?@action=redirect&bpo=38234]: Py_SetPath() now sets sys.executable to the program full path (Py_GetProgramFullPath()) rather than to the program name (Py_GetProgramName()).

bpo-38234 [https://bugs.python.org/issue?@action=redirect&bpo=38234]: Python ignored arguments passed to Py_SetPath(), Py_SetPythonHome() and Py_SetProgramName(): fix Python initialization to use specified arguments.

bpo-38205 [https://bugs.python.org/issue?@action=redirect&bpo=38205]: The Py_UNREACHABLE() macro now calls Py_FatalError().

bpo-38140 [https://bugs.python.org/issue?@action=redirect&bpo=38140]: Make dict and weakref offsets opaque for C heap types by passing the offsets through PyMemberDef

bpo-15088 [https://bugs.python.org/issue?@action=redirect&bpo=15088]: The C function PyGen_NeedsFinalizing has been removed. It was not documented, tested or used anywhere within CPython after the implementation of PEP 442 [https://peps.python.org/pep-0442/]. Patch by Joannah Nanjekye. (Patch by Joannah Nanjekye)

bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763]: Options added by PySys_AddXOption() are now handled the same way than PyConfig.xoptions and command line -X options.

bpo-37926 [https://bugs.python.org/issue?@action=redirect&bpo=37926]: Fix a crash in PySys_SetArgvEx(0, NULL, 0).

bpo-37879 [https://bugs.python.org/issue?@action=redirect&bpo=37879]: Fix subtype_dealloc to suppress the type decref when the base type is a C heap type

bpo-37645 [https://bugs.python.org/issue?@action=redirect&bpo=37645]: Add _PyObject_FunctionStr() to get a user-friendly string representation of a function-like object. Patch by Jeroen Demeyer.

bpo-29548 [https://bugs.python.org/issue?@action=redirect&bpo=29548]: The functions PyEval_CallObject, PyEval_CallFunction, PyEval_CallMethod and PyEval_CallObjectWithKeywords are deprecated. Use PyObject_Call() and its variants instead.

bpo-37151 [https://bugs.python.org/issue?@action=redirect&bpo=37151]: PyCFunction_Call is now a deprecated alias of PyObject_Call().

bpo-37540 [https://bugs.python.org/issue?@action=redirect&bpo=37540]: The vectorcall protocol now requires that the caller passes only strings as keyword names.

bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: The vectorcall protocol is now enabled for type objects: set tp_vectorcall to a vectorcall function to be used instead of tp_new and tp_init when calling the class itself.

bpo-21120 [https://bugs.python.org/issue?@action=redirect&bpo=21120]: Exclude Python-ast.h, ast.h and asdl.h from the limited API.

bpo-37483 [https://bugs.python.org/issue?@action=redirect&bpo=37483]: Add new function _PyObject_CallOneArg for calling an object with one positional argument.

bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763]: Add PyConfig_SetWideStringList() function.

bpo-37337 [https://bugs.python.org/issue?@action=redirect&bpo=37337]: Add fast functions for calling methods: _PyObject_VectorcallMethod(), _PyObject_CallMethodNoArgs() and _PyObject_CallMethodOneArg().

bpo-28805 [https://bugs.python.org/issue?@action=redirect&bpo=28805]: The METH_FASTCALL calling convention has been documented.

bpo-37221 [https://bugs.python.org/issue?@action=redirect&bpo=37221]: The new function PyCode_NewWithPosOnlyArgs() allows to create code objects like PyCode_New(), but with an extra posonlyargcount parameter for indicating the number of positonal-only arguments.

bpo-37215 [https://bugs.python.org/issue?@action=redirect&bpo=37215]: Fix dtrace issue introduce by bpo-36842 [https://bugs.python.org/issue?@action=redirect&bpo=36842]

bpo-37194 [https://bugs.python.org/issue?@action=redirect&bpo=37194]: Add a new public PyObject_CallNoArgs() function to the C API: call a callable Python object without any arguments. It is the most efficient way to call a callback without any argument. On x86-64, for example, PyObject_CallFunctionObjArgs(func, NULL) allocates 960 bytes on the stack per call, whereas PyObject_CallNoArgs(func) only allocates 624 bytes per call.

bpo-37170 [https://bugs.python.org/issue?@action=redirect&bpo=37170]: Fix the cast on error in PyLong_AsUnsignedLongLongMask().

bpo-35381 [https://bugs.python.org/issue?@action=redirect&bpo=35381]: Convert posixmodule.c statically allocated types DirEntryType and ScandirIteratorType to heap-allocated types.

bpo-34331 [https://bugs.python.org/issue?@action=redirect&bpo=34331]: Use singular/plural noun in error message when instantiating an abstract class with non-overridden abstract method(s).

Python 3.8.0 beta 1

Release date: 2019-06-04

Security

bpo-35907 [https://bugs.python.org/issue?@action=redirect&bpo=35907]: CVE 2019-9948 [https://www.cve.org/CVERecord?id=CVE-2019-9948]: Avoid file reading by disallowing local-file:// and local_file:// URL schemes in URLopener().open() and URLopener().retrieve() of urllib.request.

bpo-33529 [https://bugs.python.org/issue?@action=redirect&bpo=33529]: Prevent fold function used in email header encoding from entering infinite loop when there are too many non-ASCII characters in a header.

bpo-33164 [https://bugs.python.org/issue?@action=redirect&bpo=33164]: Updated blake2 implementation which uses secure memset implementation provided by platform.

Core and Builtins

bpo-35814 [https://bugs.python.org/issue?@action=redirect&bpo=35814]: Allow unpacking in the right hand side of annotated assignments. In particular, t: Tuple[int, ...] = x, y, *z is now allowed.

bpo-37126 [https://bugs.python.org/issue?@action=redirect&bpo=37126]: All structseq objects are now tracked by the garbage collector. Patch by Pablo Galindo.

bpo-37122 [https://bugs.python.org/issue?@action=redirect&bpo=37122]: Make the co_argcount attribute of code objects represent the total number of positional arguments (including positional-only arguments). The value of co_posonlyargcount can be used to distinguish which arguments are positional only, and the difference (co_argcount - co_posonlyargcount) is the number of positional-or-keyword arguments. Patch by Pablo Galindo.

bpo-20092 [https://bugs.python.org/issue?@action=redirect&bpo=20092]: Constructors of int, float and complex will now use the __index__() special method, if available and the corresponding method __int__(), __float__() or __complex__() is not available.

bpo-37087 [https://bugs.python.org/issue?@action=redirect&bpo=37087]: Add native thread ID (TID) support to OpenBSD.

bpo-26219 [https://bugs.python.org/issue?@action=redirect&bpo=26219]: Implemented per opcode cache mechanism and LOAD_GLOBAL instruction use it. LOAD_GLOBAL is now about 40% faster. Contributed by Yury Selivanov, and Inada Naoki.

bpo-37072 [https://bugs.python.org/issue?@action=redirect&bpo=37072]: Fix crash in PyAST_FromNodeObject() when flags is NULL.

bpo-37029 [https://bugs.python.org/issue?@action=redirect&bpo=37029]: Freeing a great many small objects could take time quadratic in the number of arenas, due to using linear search to keep obmalloc.c’s list of usable arenas sorted by order of number of free memory pools. This is accomplished without search now, leaving the worst-case time linear in the number of arenas. For programs where this quite visibly matters (typically with more than 100 thousand small objects alive simultaneously), this can greatly reduce the time needed to release their memory.

bpo-26423 [https://bugs.python.org/issue?@action=redirect&bpo=26423]: Fix possible overflow in wrap_lenfunc() when sizeof(long) < sizeof(Py_ssize_t) (e.g., 64-bit Windows).

bpo-37050 [https://bugs.python.org/issue?@action=redirect&bpo=37050]: Improve the AST for “debug” f-strings, which use ‘=’ to print out the source of the expression being evaluated. Delete expr_text from the FormattedValue node, and instead use a Constant string node (possibly merged with adjacent constant expressions inside the f-string).

bpo-22385 [https://bugs.python.org/issue?@action=redirect&bpo=22385]: The bytes.hex, bytearray.hex, and memoryview.hex methods as well as the binascii.hexlify and b2a_hex functions now have the ability to include an optional separator between hex bytes. This functionality was inspired by MicroPython’s hexlify implementation.

bpo-26836 [https://bugs.python.org/issue?@action=redirect&bpo=26836]: Add os.memfd_create().

bpo-37032 [https://bugs.python.org/issue?@action=redirect&bpo=37032]: Added new replace() method to the code type (types.CodeType).

bpo-37007 [https://bugs.python.org/issue?@action=redirect&bpo=37007]: Implement socket.if_nameindex(), socket.if_nametoindex(), and socket.if_indextoname() on Windows.

bpo-36829 [https://bugs.python.org/issue?@action=redirect&bpo=36829]: PyErr_WriteUnraisable() now creates a traceback object if there is no current traceback. Moreover, call PyErr_NormalizeException() and PyException_SetTraceback() to normalize the exception value. Ignore any error.

bpo-36878 [https://bugs.python.org/issue?@action=redirect&bpo=36878]: Only accept text after # type: ignore if the first character is ASCII. This is to disallow things like # type: ignoreé.

bpo-36878 [https://bugs.python.org/issue?@action=redirect&bpo=36878]: Store text appearing after a # type: ignore comment in the AST. For example a type ignore like # type: ignore[E1000] will have the string "[E1000]" stored in its AST node.

bpo-2180 [https://bugs.python.org/issue?@action=redirect&bpo=2180]: Treat line continuation at EOF as a SyntaxError by Anthony Sottile.

bpo-36907 [https://bugs.python.org/issue?@action=redirect&bpo=36907]: Fix a crash when calling a C function with a keyword dict (f(**kwargs)) and changing the dict kwargs while that function is running.

bpo-36946 [https://bugs.python.org/issue?@action=redirect&bpo=36946]: Fix possible signed integer overflow when handling slices.

bpo-36826 [https://bugs.python.org/issue?@action=redirect&bpo=36826]: Add NamedExpression kind support to ast_unparse.c

bpo-1875 [https://bugs.python.org/issue?@action=redirect&bpo=1875]: A SyntaxError is now raised if a code blocks that will be optimized away (e.g. if conditions that are always false) contains syntax errors. Patch by Pablo Galindo.

bpo-36027 [https://bugs.python.org/issue?@action=redirect&bpo=36027]: Allow computation of modular inverses via three-argument pow: the second argument is now permitted to be negative in the case where the first and third arguments are relatively prime.

bpo-36861 [https://bugs.python.org/issue?@action=redirect&bpo=36861]: Update the Unicode database to version 12.1.0.

bpo-28866 [https://bugs.python.org/issue?@action=redirect&bpo=28866]: Avoid caching attributes of classes which type defines mro() to avoid a hard cache invalidation problem.

bpo-36851 [https://bugs.python.org/issue?@action=redirect&bpo=36851]: The FrameType stack is now correctly cleaned up if the execution ends with a return and the stack is not empty.

bpo-34616 [https://bugs.python.org/issue?@action=redirect&bpo=34616]: The compile() builtin functions now support the ast.PyCF_ALLOW_TOP_LEVEL_AWAIT flag, which allow to compile sources that contains top-level await, async with or async for. This is useful to evaluate async-code from with an already async functions; for example in a custom REPL.

bpo-36842 [https://bugs.python.org/issue?@action=redirect&bpo=36842]: Implement PEP 578, adding sys.audit, io.open_code and related APIs.

bpo-27639 [https://bugs.python.org/issue?@action=redirect&bpo=27639]: Correct return type for UserList slicing operations. Patch by Michael Blahay, Erick Cervantes, and vaultah

bpo-36737 [https://bugs.python.org/issue?@action=redirect&bpo=36737]: Move PyRuntimeState.warnings into per-interpreter state (via “module state”).

bpo-36793 [https://bugs.python.org/issue?@action=redirect&bpo=36793]: Removed __str__ implementations from builtin types bool, int, float, complex and few classes from the standard library. They now inherit __str__() from object.

bpo-36817 [https://bugs.python.org/issue?@action=redirect&bpo=36817]: Add a = feature f-strings for debugging. This can precede !s, !r, or !a. It produces the text of the expression, followed by an equal sign, followed by the repr of the value of the expression. So f'{3*9+15=}' would be equal to the string '3*9+15=42'. If = is specified, the default conversion is set to !r, unless a format spec is given, in which case the formatting behavior is unchanged, and __format__ will be used.

bpo-24048 [https://bugs.python.org/issue?@action=redirect&bpo=24048]: Save the live exception during import.c’s remove_module().

bpo-27987 [https://bugs.python.org/issue?@action=redirect&bpo=27987]: pymalloc returns memory blocks aligned by 16 bytes, instead of 8 bytes, on 64-bit platforms to conform x86-64 ABI. Recent compilers assume this alignment more often. Patch by Inada Naoki.

bpo-36601 [https://bugs.python.org/issue?@action=redirect&bpo=36601]: A long-since-meaningless check for getpid() == main_pid was removed from Python’s internal C signal handler.

bpo-36594 [https://bugs.python.org/issue?@action=redirect&bpo=36594]: Fix incorrect use of %p in format strings. Patch by Zackery Spytz.

bpo-36045 [https://bugs.python.org/issue?@action=redirect&bpo=36045]: builtins.help() now prefixes async for async functions.

bpo-36084 [https://bugs.python.org/issue?@action=redirect&bpo=36084]: Add native thread ID (TID) to threading.Thread objects (supported platforms: Windows, FreeBSD, Linux, macOS)

bpo-36035 [https://bugs.python.org/issue?@action=redirect&bpo=36035]: Added fix for broken symlinks in combination with pathlib

bpo-35983 [https://bugs.python.org/issue?@action=redirect&bpo=35983]: Added new trashcan macros to deal with a double deallocation that could occur when the tp_dealloc of a subclass calls the tp_dealloc of a base class and that base class uses the trashcan mechanism. Patch by Jeroen Demeyer.

bpo-20602 [https://bugs.python.org/issue?@action=redirect&bpo=20602]: Do not clear sys.flags and sys.float_info during shutdown. Patch by Zackery Spytz.

bpo-26826 [https://bugs.python.org/issue?@action=redirect&bpo=26826]: Expose copy_file_range() as a low level API in the os module.

bpo-32388 [https://bugs.python.org/issue?@action=redirect&bpo=32388]: Remove cross-version binary compatibility requirement in tp_flags.

bpo-31862 [https://bugs.python.org/issue?@action=redirect&bpo=31862]: Port binascii to PEP 489 multiphase initialization. Patch by Marcel Plch.

Library

bpo-37128 [https://bugs.python.org/issue?@action=redirect&bpo=37128]: Added math.perm().

bpo-37120 [https://bugs.python.org/issue?@action=redirect&bpo=37120]: Add SSLContext.num_tickets to control the number of TLSv1.3 session tickets.

bpo-12202 [https://bugs.python.org/issue?@action=redirect&bpo=12202]: Fix the error handling in msilib.SummaryInformation.GetProperty(). Patch by Zackery Spytz.

bpo-26835 [https://bugs.python.org/issue?@action=redirect&bpo=26835]: The fcntl module now contains file sealing constants for sealing of memfds.

bpo-29262 [https://bugs.python.org/issue?@action=redirect&bpo=29262]: Add get_origin() and get_args() introspection helpers to typing module.

bpo-12639 [https://bugs.python.org/issue?@action=redirect&bpo=12639]: msilib.Directory.start_component() no longer fails if keyfile is not None.

bpo-36999 [https://bugs.python.org/issue?@action=redirect&bpo=36999]: Add the asyncio.Task.get_coro() method to publicly expose the tasks’s coroutine object.

bpo-35246 [https://bugs.python.org/issue?@action=redirect&bpo=35246]: Make asyncio.create_subprocess_exec() accept path-like arguments.

bpo-35279 [https://bugs.python.org/issue?@action=redirect&bpo=35279]: Change default max_workers of ThreadPoolExecutor from cpu_count() * 5 to min(32, cpu_count() + 4). Previous value was unreasonably large on many cores machines.

bpo-37076 [https://bugs.python.org/issue?@action=redirect&bpo=37076]: _thread.start_new_thread() now logs uncaught exception raised by the function using sys.unraisablehook(), rather than sys.excepthook(), so the hook gets access to the function which raised the exception.

bpo-33725 [https://bugs.python.org/issue?@action=redirect&bpo=33725]: On macOS, the multiprocessing module now uses spawn start method by default.

bpo-37054 [https://bugs.python.org/issue?@action=redirect&bpo=37054]: Fix destructor _pyio.BytesIO and _pyio.TextIOWrapper: initialize their _buffer attribute as soon as possible (in the class body), because it’s used by __del__() which calls close().

bpo-37058 [https://bugs.python.org/issue?@action=redirect&bpo=37058]: PEP 544: Add Protocol and @runtime_checkable to the typing module.

bpo-36933 [https://bugs.python.org/issue?@action=redirect&bpo=36933]: The functions sys.set_coroutine_wrapper and sys.get_coroutine_wrapper that were deprecated and marked for removal in 3.8 have been removed.

bpo-37047 [https://bugs.python.org/issue?@action=redirect&bpo=37047]: Handle late binding and attribute access in unittest.mock.AsyncMock setup for autospeccing. Document newly implemented async methods in unittest.mock.MagicMock.

bpo-37049 [https://bugs.python.org/issue?@action=redirect&bpo=37049]: PEP 589: Add TypedDict to the typing module.

bpo-37046 [https://bugs.python.org/issue?@action=redirect&bpo=37046]: PEP 586: Add Literal to the typing module.

bpo-37045 [https://bugs.python.org/issue?@action=redirect&bpo=37045]: PEP 591: Add Final qualifier and @final decorator to the typing module.

bpo-37035 [https://bugs.python.org/issue?@action=redirect&bpo=37035]: Don’t log OSError based exceptions if a fatal error has occurred in asyncio transport. Peer can generate almost any OSError, user cannot avoid these exceptions by fixing own code. Errors are still propagated to user code, it’s just logging them is pointless and pollute asyncio logs.

bpo-37001 [https://bugs.python.org/issue?@action=redirect&bpo=37001]: symtable.symtable() now accepts the same input types for source code as the built-in compile() function. Patch by Dino Viehland.

bpo-37028 [https://bugs.python.org/issue?@action=redirect&bpo=37028]: Implement asyncio REPL

bpo-37027 [https://bugs.python.org/issue?@action=redirect&bpo=37027]: Return safe to use proxy socket object from transport.get_extra_info(‘socket’)

bpo-32528 [https://bugs.python.org/issue?@action=redirect&bpo=32528]: Make asyncio.CancelledError a BaseException.

This will address the common mistake many asyncio users make: an “except Exception” clause breaking Tasks cancellation.

In addition to this change, we stop inheriting asyncio.TimeoutError and asyncio.InvalidStateError from their concurrent.futures.* counterparts. There’s no point for these exceptions to share the inheritance chain.

bpo-1230540 [https://bugs.python.org/issue?@action=redirect&bpo=1230540]: Add a new threading.excepthook() function which handles uncaught threading.Thread.run() exception. It can be overridden to control how uncaught threading.Thread.run() exceptions are handled.

bpo-36996 [https://bugs.python.org/issue?@action=redirect&bpo=36996]: Handle unittest.mock.patch() used as a decorator on async functions.

bpo-37008 [https://bugs.python.org/issue?@action=redirect&bpo=37008]: Add support for calling next() with the mock resulting from unittest.mock.mock_open()

bpo-27737 [https://bugs.python.org/issue?@action=redirect&bpo=27737]: Allow whitespace only header encoding in email.header - by Batuhan Taskaya

bpo-36969 [https://bugs.python.org/issue?@action=redirect&bpo=36969]: PDB command args now display positional only arguments. Patch contributed by Rémi Lapeyre.

bpo-36969 [https://bugs.python.org/issue?@action=redirect&bpo=36969]: PDB command args now display keyword only arguments. Patch contributed by Rémi Lapeyre.

bpo-36983 [https://bugs.python.org/issue?@action=redirect&bpo=36983]: Add missing names to typing.__all__: ChainMap, ForwardRef, OrderedDict - by Anthony Sottile.

bpo-36972 [https://bugs.python.org/issue?@action=redirect&bpo=36972]: Add SupportsIndex protocol to the typing module to allow type checking to detect classes that can be passed to hex(), oct() and bin().

bpo-32972 [https://bugs.python.org/issue?@action=redirect&bpo=32972]: Implement unittest.IsolatedAsyncioTestCase to help testing asyncio-based code.

bpo-36952 [https://bugs.python.org/issue?@action=redirect&bpo=36952]: fileinput.input() and fileinput.FileInput bufsize argument has been removed (was deprecated and ignored since Python 3.6), and as a result the mode and openhook arguments have been made keyword-only.

bpo-36952 [https://bugs.python.org/issue?@action=redirect&bpo=36952]: Starting with Python 3.3, importing ABCs from collections is deprecated, and import should be done from collections.abc. Still being able to import from collections was marked for removal in 3.8, but has been delayed to 3.9; documentation and DeprecationWarning clarified.

bpo-36949 [https://bugs.python.org/issue?@action=redirect&bpo=36949]: Implement __repr__ for WeakSet objects.

bpo-36948 [https://bugs.python.org/issue?@action=redirect&bpo=36948]: Fix NameError in urllib.request.URLopener.retrieve(). Patch by Karthikeyan Singaravelan.

bpo-33524 [https://bugs.python.org/issue?@action=redirect&bpo=33524]: Fix the folding of email header when the max_line_length is 0 or None and the header contains non-ascii characters. Contributed by Licht Takeuchi (@Licht-T).

bpo-24564 [https://bugs.python.org/issue?@action=redirect&bpo=24564]: shutil.copystat() now ignores errno.EINVAL on os.setxattr() which may occur when copying files on filesystems without extended attributes support.

Original patch by Giampaolo Rodola, updated by Ying Wang.

bpo-36888 [https://bugs.python.org/issue?@action=redirect&bpo=36888]: Python child processes can now access the status of their parent process using multiprocessing.process.parent_process

bpo-36921 [https://bugs.python.org/issue?@action=redirect&bpo=36921]: Deprecate @coroutine for sake of async def.

bpo-25652 [https://bugs.python.org/issue?@action=redirect&bpo=25652]: Fix bug in __rmod__ of UserString - by Batuhan Taskaya.

bpo-36916 [https://bugs.python.org/issue?@action=redirect&bpo=36916]: Remove a message about an unhandled exception in a task when writer.write() is used without await and writer.drain() fails with an exception.

bpo-36889 [https://bugs.python.org/issue?@action=redirect&bpo=36889]: Introduce asyncio.Stream class that merges asyncio.StreamReader and asyncio.StreamWriter functionality. asyncio.Stream can work in readonly, writeonly and readwrite modes. Provide asyncio.connect(), asyncio.connect_unix(), asyncio.connect_read_pipe() and asyncio.connect_write_pipe() factories to open asyncio.Stream connections. Provide asyncio.StreamServer and UnixStreamServer to serve servers with asyncio.Stream API. Modify asyncio.create_subprocess_shell() and asyncio.create_subprocess_exec() to use asyncio.Stream instead of deprecated StreamReader and StreamWriter. Deprecate asyncio.StreamReader and asyncio.StreamWriter. Deprecate usage of private classes, e.g. asyncio.FlowControlMixing and asyncio.StreamReaderProtocol outside of asyncio package.

bpo-36845 [https://bugs.python.org/issue?@action=redirect&bpo=36845]: Added validation of integer prefixes to the construction of IP networks and interfaces in the ipaddress module.

bpo-23378 [https://bugs.python.org/issue?@action=redirect&bpo=23378]: Add an extend action to argparser.

bpo-36867 [https://bugs.python.org/issue?@action=redirect&bpo=36867]: Fix a bug making a SharedMemoryManager instance and its parent process use two separate resource_tracker processes.

bpo-23896 [https://bugs.python.org/issue?@action=redirect&bpo=23896]: Adds a grammar to lib2to3.pygram that contains exec as a function not as statement.

bpo-36895 [https://bugs.python.org/issue?@action=redirect&bpo=36895]: The function time.clock() was deprecated in 3.3 in favor of time.perf_counter() and marked for removal in 3.8, it has removed.

bpo-35545 [https://bugs.python.org/issue?@action=redirect&bpo=35545]: Fix asyncio discarding IPv6 scopes when ensuring hostname resolutions internally

bpo-36887 [https://bugs.python.org/issue?@action=redirect&bpo=36887]: Add new function math.isqrt() to compute integer square roots.

bpo-34632 [https://bugs.python.org/issue?@action=redirect&bpo=34632]: Introduce the importlib.metadata module with (provisional) support for reading metadata from third-party packages.

bpo-36878 [https://bugs.python.org/issue?@action=redirect&bpo=36878]: When using type_comments=True in ast.parse, treat # type: ignore followed by a non-alphanumeric character and then arbitrary text as a type ignore, instead of requiring nothing but whitespace or another comment. This is to permit formations such as # type: ignore[E1000].

bpo-36778 [https://bugs.python.org/issue?@action=redirect&bpo=36778]: cp65001 encoding (Windows code page 65001) becomes an alias to utf_8 encoding.

bpo-36867 [https://bugs.python.org/issue?@action=redirect&bpo=36867]: The multiprocessing.resource_tracker replaces the multiprocessing.semaphore_tracker module. Other than semaphores, resource_tracker also tracks shared_memory segments.

bpo-30262 [https://bugs.python.org/issue?@action=redirect&bpo=30262]: The Cache and Statement objects of the sqlite3 module are not exposed to the user. Patch by Aviv Palivoda.

bpo-24538 [https://bugs.python.org/issue?@action=redirect&bpo=24538]: In shutil.copystat(), first copy extended file attributes and then file permissions, since extended attributes can only be set on the destination while it is still writeable.

bpo-36829 [https://bugs.python.org/issue?@action=redirect&bpo=36829]: Add new sys.unraisablehook() function which can be overridden to control how “unraisable exceptions” are handled. It is called when an exception has occurred but there is no way for Python to handle it. For example, when a destructor raises an exception or during garbage collection (gc.collect()).

bpo-36832 [https://bugs.python.org/issue?@action=redirect&bpo=36832]: Introducing zipfile.Path, a pathlib-compatible wrapper for traversing zip files.

bpo-36814 [https://bugs.python.org/issue?@action=redirect&bpo=36814]: Fix an issue where os.posix_spawnp() would incorrectly raise a TypeError when file_actions is None.

bpo-33110 [https://bugs.python.org/issue?@action=redirect&bpo=33110]: Handle exceptions raised by functions added by concurrent.futures add_done_callback correctly when the Future has already completed.

bpo-26903 [https://bugs.python.org/issue?@action=redirect&bpo=26903]: Limit max_workers in ProcessPoolExecutor to 61 to work around a WaitForMultipleObjects limitation.

bpo-36813 [https://bugs.python.org/issue?@action=redirect&bpo=36813]: Fix QueueListener to call queue.task_done() upon stopping. Patch by Bar Harel.

bpo-36806 [https://bugs.python.org/issue?@action=redirect&bpo=36806]: Forbid creation of asyncio stream objects like StreamReader, StreamWriter, Process, and their protocols outside of asyncio package.

bpo-36802 [https://bugs.python.org/issue?@action=redirect&bpo=36802]: Provide both sync and async calls for StreamWriter.write() and StreamWriter.close()

bpo-36801 [https://bugs.python.org/issue?@action=redirect&bpo=36801]: Properly handle SSL connection closing in asyncio StreamWriter.drain() call.

bpo-36785 [https://bugs.python.org/issue?@action=redirect&bpo=36785]: Implement PEP 574 (pickle protocol 5 with out-of-band buffers).

bpo-36772 [https://bugs.python.org/issue?@action=redirect&bpo=36772]: functools.lru_cache() can now be used as a straight decorator in addition to its existing usage as a function that returns a decorator.

bpo-6584 [https://bugs.python.org/issue?@action=redirect&bpo=6584]: Add a BadGzipFile exception to the gzip module.

bpo-36748 [https://bugs.python.org/issue?@action=redirect&bpo=36748]: Optimized write buffering in C implementation of TextIOWrapper. Writing ASCII string to TextIOWrapper with ascii, latin1, or utf-8 encoding is about 20% faster. Patch by Inada Naoki.

bpo-8138 [https://bugs.python.org/issue?@action=redirect&bpo=8138]: Don’t mark wsgiref.simple_server.SimpleServer as multi-threaded since wsgiref.simple_server.WSGIServer is single-threaded.

bpo-22640 [https://bugs.python.org/issue?@action=redirect&bpo=22640]: py_compile.compile() now supports silent mode. Patch by Joannah Nanjekye

bpo-29183 [https://bugs.python.org/issue?@action=redirect&bpo=29183]: Fix double exceptions in wsgiref.handlers.BaseHandler by calling its close() method only when no exception is raised.

bpo-36548 [https://bugs.python.org/issue?@action=redirect&bpo=36548]: Improved the repr of regular expression flags.

bpo-36542 [https://bugs.python.org/issue?@action=redirect&bpo=36542]: The signature of Python functions can now be overridden by specifying the __text_signature__ attribute.

bpo-36533 [https://bugs.python.org/issue?@action=redirect&bpo=36533]: Reinitialize logging.Handler locks in forked child processes instead of attempting to acquire them all in the parent before forking only to be released in the child process. The acquire/release pattern was leading to deadlocks in code that has implemented any form of chained logging handlers that depend upon one another as the lock acquisition order cannot be guaranteed.

bpo-35252 [https://bugs.python.org/issue?@action=redirect&bpo=35252]: Throw a TypeError instead of an AssertionError when using an invalid type annotation with singledispatch.

bpo-35900 [https://bugs.python.org/issue?@action=redirect&bpo=35900]: Allow reduction methods to return a 6-item tuple where the 6th item specifies a custom state-setting method that’s called instead of the regular __setstate__ method.

bpo-35900 [https://bugs.python.org/issue?@action=redirect&bpo=35900]: enable custom reduction callback registration for functions and classes in _pickle.c, using the new Pickler’s attribute reducer_override

bpo-36368 [https://bugs.python.org/issue?@action=redirect&bpo=36368]: Fix a bug crashing SharedMemoryManager instances in interactive sessions after a ctrl-c (KeyboardInterrupt) was sent

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix mmap fail for VxWorks

bpo-27497 [https://bugs.python.org/issue?@action=redirect&bpo=27497]: csv.DictWriter.writeheader() now returns the return value of the underlying csv.Writer.writerow() method. Patch contributed by Ashish Nitin Patil.

bpo-36239 [https://bugs.python.org/issue?@action=redirect&bpo=36239]: Parsing .mo files now ignores comments starting and ending with #-#-#-#-#.

bpo-26707 [https://bugs.python.org/issue?@action=redirect&bpo=26707]: Enable plistlib to read and write binary plist files that were created as a KeyedArchive file. Specifically, this allows the plistlib to process 0x80 tokens as UID objects.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Add posix module support for VxWorks.

bpo-35125 [https://bugs.python.org/issue?@action=redirect&bpo=35125]: Asyncio: Remove inner callback on outer cancellation in shield

bpo-35721 [https://bugs.python.org/issue?@action=redirect&bpo=35721]: Fix asyncio.SelectorEventLoop.subprocess_exec() leaks file descriptors if Popen fails and called with stdin=subprocess.PIPE. Patch by Niklas Fiekas.

bpo-31855 [https://bugs.python.org/issue?@action=redirect&bpo=31855]: unittest.mock.mock_open() results now respects the argument of read([size]). Patch contributed by Rémi Lapeyre.

bpo-35431 [https://bugs.python.org/issue?@action=redirect&bpo=35431]: Implement math.comb() that returns binomial coefficient, that computes the number of ways to choose k items from n items without repetition and without order. Patch by Yash Aggarwal and Keller Fuchs.

bpo-26660 [https://bugs.python.org/issue?@action=redirect&bpo=26660]: Fixed permission errors in TemporaryDirectory clean up. Previously TemporaryDirectory.cleanup() failed when non-writeable or non-searchable files or directories were created inside a temporary directory.

bpo-34271 [https://bugs.python.org/issue?@action=redirect&bpo=34271]: Add debugging helpers to ssl module. It’s now possible to dump key material and to trace TLS protocol. The default and stdlib contexts also support SSLKEYLOGFILE env var.

bpo-26467 [https://bugs.python.org/issue?@action=redirect&bpo=26467]: Added AsyncMock to support using unittest to mock asyncio coroutines. Patch by Lisa Roach.

bpo-33569 [https://bugs.python.org/issue?@action=redirect&bpo=33569]: dataclasses.InitVar: Exposes the type used to create the init var.

bpo-34424 [https://bugs.python.org/issue?@action=redirect&bpo=34424]: Fix serialization of messages containing encoded strings when the policy.linesep is set to a multi-character string. Patch by Jens Troeger.

bpo-34303 [https://bugs.python.org/issue?@action=redirect&bpo=34303]: Performance of functools.reduce() is slightly improved. Patch by Sergey Fedoseev.

bpo-33361 [https://bugs.python.org/issue?@action=redirect&bpo=33361]: Fix a bug in codecs.StreamRecoder where seeking might leave old data in a buffer and break subsequent read calls. Patch by Ammar Askar.

bpo-22454 [https://bugs.python.org/issue?@action=redirect&bpo=22454]: The shlex module now exposes shlex.join(), the inverse of shlex.split(). Patch by Bo Bayles.

bpo-31922 [https://bugs.python.org/issue?@action=redirect&bpo=31922]: asyncio.AbstractEventLoop.create_datagram_endpoint(): Do not connect UDP socket when broadcast is allowed. This allows to receive replies after a UDP broadcast.

bpo-24882 [https://bugs.python.org/issue?@action=redirect&bpo=24882]: Change ThreadPoolExecutor to use existing idle threads before spinning up new ones.

bpo-31961 [https://bugs.python.org/issue?@action=redirect&bpo=31961]: Added support for bytes and path-like objects in subprocess.Popen() on Windows. The args parameter now accepts a path-like object if shell is False and a sequence containing bytes and path-like objects. The executable parameter now accepts a bytes and path-like object. The cwd parameter now accepts a bytes object. Based on patch by Anders Lorentsen.

bpo-33123 [https://bugs.python.org/issue?@action=redirect&bpo=33123]: pathlib.Path.unlink now accepts a missing_ok parameter to avoid a FileNotFoundError from being raised. Patch by Robert Buchholz.

bpo-32941 [https://bugs.python.org/issue?@action=redirect&bpo=32941]: Allow mmap.mmap objects to access the madvise() system call (through mmap.mmap.madvise()).

bpo-22102 [https://bugs.python.org/issue?@action=redirect&bpo=22102]: Added support for ZIP files with disks set to 0. Such files are commonly created by builtin tools on Windows when use ZIP64 extension. Patch by Francisco Facioni.

bpo-32515 [https://bugs.python.org/issue?@action=redirect&bpo=32515]: trace.py can now run modules via python3 -m trace -t –module module_name

bpo-32299 [https://bugs.python.org/issue?@action=redirect&bpo=32299]: Changed unittest.mock.patch.dict() to return the patched dictionary when used as context manager. Patch by Vadim Tsander.

bpo-27141 [https://bugs.python.org/issue?@action=redirect&bpo=27141]: Added a __copy__() to collections.UserList and collections.UserDict in order to correctly implement shallow copying of the objects. Patch by Bar Harel.

bpo-31829 [https://bugs.python.org/issue?@action=redirect&bpo=31829]: \r, \0 and \x1a (end-of-file on Windows) are now escaped in protocol 0 pickles of Unicode strings. This allows to load them without loss from files open in text mode in Python 2.

bpo-23395 [https://bugs.python.org/issue?@action=redirect&bpo=23395]: _thread.interrupt_main() now avoids setting the Python error status if the SIGINT signal is ignored or not handled by Python.

Documentation

bpo-36896 [https://bugs.python.org/issue?@action=redirect&bpo=36896]: Clarify that some types have unstable constructor signature between Python versions.

bpo-36686 [https://bugs.python.org/issue?@action=redirect&bpo=36686]: Improve documentation of the stdin, stdout, and stderr arguments of the asyncio.subprocess_exec function to specify which values are supported. Also mention that decoding as text is not supported.

Add a few tests to verify that the various values passed to the std* arguments actually work.

bpo-36984 [https://bugs.python.org/issue?@action=redirect&bpo=36984]: Improve version added references in typing module - by Anthony Sottile.

bpo-36868 [https://bugs.python.org/issue?@action=redirect&bpo=36868]: What’s new now mentions SSLContext.hostname_checks_common_name instead of SSLContext.host_flags.

bpo-35924 [https://bugs.python.org/issue?@action=redirect&bpo=35924]: Add a note to the curses.addstr() documentation to warn that multiline strings can cause segfaults because of an ncurses bug.

bpo-36783 [https://bugs.python.org/issue?@action=redirect&bpo=36783]: Added C API Documentation for Time_FromTimeAndFold and PyDateTime_FromDateAndTimeAndFold as per PEP 495. Patch by Edison Abahurire.

bpo-36797 [https://bugs.python.org/issue?@action=redirect&bpo=36797]: More of the legacy distutils documentation has been either pruned, or else more clearly marked as being retained solely until the setuptools documentation covers it independently.

bpo-22865 [https://bugs.python.org/issue?@action=redirect&bpo=22865]: Add detail to the documentation on the pty.spawn function.

bpo-35397 [https://bugs.python.org/issue?@action=redirect&bpo=35397]: Remove deprecation and document urllib.parse.unwrap(). Patch contributed by Rémi Lapeyre.

bpo-32995 [https://bugs.python.org/issue?@action=redirect&bpo=32995]: Added the context variable in glossary.

bpo-33519 [https://bugs.python.org/issue?@action=redirect&bpo=33519]: Clarify that copy() is not part of the MutableSequence ABC.

bpo-33482 [https://bugs.python.org/issue?@action=redirect&bpo=33482]: Make codecs.StreamRecoder.writelines take a list of bytes.

bpo-25735 [https://bugs.python.org/issue?@action=redirect&bpo=25735]: Added documentation for func factorial to indicate that returns integer values

bpo-20285 [https://bugs.python.org/issue?@action=redirect&bpo=20285]: Expand object.__doc__ (docstring) to make it clearer. Modify pydoc.py so that help(object) lists object methods (for other classes, help omits methods of the object base class.)

Tests

bpo-37069 [https://bugs.python.org/issue?@action=redirect&bpo=37069]: Modify test_coroutines, test_cprofile, test_generators, test_raise, test_ssl and test_yield_from to use test.support.catch_unraisable_exception() rather than test.support.captured_stderr().

bpo-37098 [https://bugs.python.org/issue?@action=redirect&bpo=37098]: Fix test_memfd_create on older Linux Kernels.

bpo-37081 [https://bugs.python.org/issue?@action=redirect&bpo=37081]: Test with OpenSSL 1.1.1c

bpo-36829 [https://bugs.python.org/issue?@action=redirect&bpo=36829]: Add test.support.catch_unraisable_exception(): context manager catching unraisable exception using sys.unraisablehook().

bpo-36915 [https://bugs.python.org/issue?@action=redirect&bpo=36915]: The main regrtest process now always removes all temporary directories of worker processes even if they crash or if they are killed on KeyboardInterrupt (CTRL+c).

bpo-36719 [https://bugs.python.org/issue?@action=redirect&bpo=36719]: “python3 -m test -jN …” now continues the execution of next tests when a worker process crash (CHILD_ERROR state). Previously, the test suite stopped immediately. Use –failfast to stop at the first error.

bpo-36816 [https://bugs.python.org/issue?@action=redirect&bpo=36816]: Update Lib/test/selfsigned_pythontestdotnet.pem to match self-signed.pythontest.net’s new TLS certificate.

bpo-35925 [https://bugs.python.org/issue?@action=redirect&bpo=35925]: Skip httplib and nntplib networking tests when they would otherwise fail due to a modern OS or distro with a default OpenSSL policy of rejecting connections to servers with weak certificates.

bpo-36782 [https://bugs.python.org/issue?@action=redirect&bpo=36782]: Add tests for several C API functions in the datetime module. Patch by Edison Abahurire.

bpo-36342 [https://bugs.python.org/issue?@action=redirect&bpo=36342]: Fix test_multiprocessing in test_venv if platform lacks functioning sem_open.

Build

bpo-36721 [https://bugs.python.org/issue?@action=redirect&bpo=36721]: To embed Python into an application, a new --embed option must be passed to python3-config --libs --embed to get -lpython3.8 (link the application to libpython). To support both 3.8 and older, try python3-config --libs --embed first and fallback to python3-config --libs (without --embed) if the previous command fails.

Add a pkg-config python-3.8-embed module to embed Python into an application: pkg-config python-3.8-embed --libs includes -lpython3.8. To support both 3.8 and older, try pkg-config python-X.Y-embed --libs first and fallback to pkg-config python-X.Y --libs (without --embed) if the previous command fails (replace X.Y with the Python version).

On the other hand, pkg-config python3.8 --libs no longer contains -lpython3.8. C extensions must not be linked to libpython (except on Android, case handled by the script); this change is backward incompatible on purpose.

bpo-36786 [https://bugs.python.org/issue?@action=redirect&bpo=36786]: “make install” now runs compileall in parallel.

Windows

bpo-36965 [https://bugs.python.org/issue?@action=redirect&bpo=36965]: include of STATUS_CONTROL_C_EXIT without depending on MSC compiler

bpo-35926 [https://bugs.python.org/issue?@action=redirect&bpo=35926]: Update to OpenSSL 1.1.1b for Windows.

bpo-29883 [https://bugs.python.org/issue?@action=redirect&bpo=29883]: Add Windows support for UDP transports for the Proactor Event Loop. Patch by Adam Meily.

bpo-33407 [https://bugs.python.org/issue?@action=redirect&bpo=33407]: The Py_DEPRECATED() macro has been implemented for MSVC.

macOS

bpo-36231 [https://bugs.python.org/issue?@action=redirect&bpo=36231]: Support building Python on macOS without /usr/include installed. As of macOS 10.14, system header files are only available within an SDK provided by either the Command Line Tools or the Xcode app.

IDLE

bpo-35610 [https://bugs.python.org/issue?@action=redirect&bpo=35610]: Replace now redundant .context_use_ps1 with .prompt_last_line. This finishes change started in bpo-31858 [https://bugs.python.org/issue?@action=redirect&bpo=31858].

bpo-37038 [https://bugs.python.org/issue?@action=redirect&bpo=37038]: Make idlelib.run runnable; add test clause.

bpo-36958 [https://bugs.python.org/issue?@action=redirect&bpo=36958]: Print any argument other than None or int passed to SystemExit or sys.exit().

bpo-36807 [https://bugs.python.org/issue?@action=redirect&bpo=36807]: When saving a file, call os.fsync() so bits are flushed to e.g. USB drive.

bpo-32411 [https://bugs.python.org/issue?@action=redirect&bpo=32411]: In browser.py, remove extraneous sorting by line number since dictionary was created in line number order.

Tools/Demos

bpo-37053 [https://bugs.python.org/issue?@action=redirect&bpo=37053]: Handle strings like u”bar” correctly in Tools/parser/unparse.py. Patch by Chih-Hsuan Yen.

C API

bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763]: Implement the PEP 587 [https://peps.python.org/pep-0587/] “Python Initialization Configuration”.

bpo-36379 [https://bugs.python.org/issue?@action=redirect&bpo=36379]: Fix crashes when attempting to use the modulo parameter when __ipow__ is implemented in C.

bpo-37107 [https://bugs.python.org/issue?@action=redirect&bpo=37107]: Update PyObject_CallMethodObjArgs() and _PyObject_CallMethodIdObjArgs to use _PyObject_GetMethod to avoid creating a bound method object in many cases. Patch by Michael J. Sullivan.

bpo-36974 [https://bugs.python.org/issue?@action=redirect&bpo=36974]: Implement PEP 590 [https://peps.python.org/pep-0590/]: Vectorcall: a fast calling protocol for CPython. This is a new protocol to optimize calls of custom callable objects.

bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763]: Py_Main() now returns the exitcode rather than calling Py_Exit(exitcode) when calling PyErr_Print() if the current exception type is SystemExit.

bpo-36922 [https://bugs.python.org/issue?@action=redirect&bpo=36922]: Add new type flag Py_TPFLAGS_METHOD_DESCRIPTOR for objects behaving like unbound methods. These are objects supporting the optimization given by the LOAD_METHOD/CALL_METHOD opcodes. See PEP 590.

bpo-36728 [https://bugs.python.org/issue?@action=redirect&bpo=36728]: The PyEval_ReInitThreads() function has been removed from the C API. It should not be called explicitly: use PyOS_AfterFork_Child() instead.

Python 3.8.0 alpha 4

Release date: 2019-05-06

Security

bpo-36742 [https://bugs.python.org/issue?@action=redirect&bpo=36742]: Fixes mishandling of pre-normalization characters in urlsplit().

bpo-30458 [https://bugs.python.org/issue?@action=redirect&bpo=30458]: Address CVE 2019-9740 [https://www.cve.org/CVERecord?id=CVE-2019-9740] by disallowing URL paths with embedded whitespace or control characters through into the underlying http client request. Such potentially malicious header injection URLs now cause an http.client.InvalidURL exception to be raised.

bpo-35755 [https://bugs.python.org/issue?@action=redirect&bpo=35755]: shutil.which() now uses os.confstr("CS_PATH") if available and if the PATH environment variable is not set. Remove also the current directory from posixpath.defpath. On Unix, shutil.which() and the subprocess module no longer search the executable in the current directory if the PATH environment variable is not set.

Core and Builtins

bpo-36722 [https://bugs.python.org/issue?@action=redirect&bpo=36722]: In debug build, import now also looks for C extensions compiled in release mode and for C extensions compiled in the stable ABI.

bpo-32849 [https://bugs.python.org/issue?@action=redirect&bpo=32849]: Fix Python Initialization code on FreeBSD to detect properly when stdin file descriptor (fd 0) is invalid.

bpo-36623 [https://bugs.python.org/issue?@action=redirect&bpo=36623]: Remove parser headers and related function declarations that lack implementations after the removal of pgen.

bpo-20180 [https://bugs.python.org/issue?@action=redirect&bpo=20180]: dict.pop() is now up to 33% faster thanks to Argument Clinic. Patch by Inada Naoki.

bpo-36611 [https://bugs.python.org/issue?@action=redirect&bpo=36611]: Debug memory allocators: disable serialno field by default from debug hooks on Python memory allocators to reduce the memory footprint by 5%. Enable tracemalloc to get the traceback where a memory block has been allocated when a fatal memory error is logged to decide where to put a breakpoint. Compile Python with PYMEM_DEBUG_SERIALNO defined to get back the field.

bpo-36588 [https://bugs.python.org/issue?@action=redirect&bpo=36588]: On AIX, sys.platform doesn’t contain the major version anymore. Always return 'aix', instead of 'aix3' .. 'aix7'. Since older Python versions include the version number, it is recommended to always use sys.platform.startswith('aix'). Contributed by M. Felt.

bpo-36549 [https://bugs.python.org/issue?@action=redirect&bpo=36549]: Change str.capitalize to use titlecase for the first character instead of uppercase.

bpo-36540 [https://bugs.python.org/issue?@action=redirect&bpo=36540]: Implement PEP 570 [https://peps.python.org/pep-0570/] (Python positional-only parameters). Patch by Pablo Galindo.

bpo-36475 [https://bugs.python.org/issue?@action=redirect&bpo=36475]: PyEval_AcquireLock() and PyEval_AcquireThread() now terminate the current thread if called while the interpreter is finalizing, making them consistent with PyEval_RestoreThread(), Py_END_ALLOW_THREADS(), and PyGILState_Ensure().

bpo-36504 [https://bugs.python.org/issue?@action=redirect&bpo=36504]: Fix signed integer overflow in _ctypes.c’s PyCArrayType_new().

bpo-20844 [https://bugs.python.org/issue?@action=redirect&bpo=20844]: Fix running script with encoding cookie and LF line ending may fail on Windows.

bpo-24214 [https://bugs.python.org/issue?@action=redirect&bpo=24214]: Fixed support of the surrogatepass error handler in the UTF-8 incremental decoder.

bpo-36452 [https://bugs.python.org/issue?@action=redirect&bpo=36452]: Changing dict keys during iteration of the dict itself, keys(), values(), or items() will now be detected in certain corner cases where keys are deleted/added so that the number of keys isn’t changed. A RuntimeError will be raised after len(dict) iterations. Contributed by Thomas Perl.

bpo-36459 [https://bugs.python.org/issue?@action=redirect&bpo=36459]: Fix a possible double PyMem_FREE() due to tokenizer.c’s tok_nextc().

bpo-36433 [https://bugs.python.org/issue?@action=redirect&bpo=36433]: Fixed TypeError message in classmethoddescr_call.

bpo-36430 [https://bugs.python.org/issue?@action=redirect&bpo=36430]: Fix a possible reference leak in itertools.count().

bpo-36440 [https://bugs.python.org/issue?@action=redirect&bpo=36440]: Include node names in ParserError messages, instead of numeric IDs. Patch by A. Skrobov.

bpo-36143 [https://bugs.python.org/issue?@action=redirect&bpo=36143]: Regenerate keyword from the Grammar and Tokens file using pgen. Patch by Pablo Galindo.

bpo-18372 [https://bugs.python.org/issue?@action=redirect&bpo=18372]: Add missing PyObject_GC_Track() calls in the pickle module. Patch by Zackery Spytz.

Library

bpo-35952 [https://bugs.python.org/issue?@action=redirect&bpo=35952]: Fix pythoninfo when the compiler is missing.

bpo-28238 [https://bugs.python.org/issue?@action=redirect&bpo=28238]: The .find*() methods of xml.etree.ElementTree can now search for wildcards like {*}tag and {ns}* that match a tag in any namespace or all tags in a namespace. Patch by Stefan Behnel.

bpo-26978 [https://bugs.python.org/issue?@action=redirect&bpo=26978]: pathlib.path.link_to() is now implemented. It creates a hard link pointing to a path.

bpo-1613500 [https://bugs.python.org/issue?@action=redirect&bpo=1613500]: fileinput.FileInput now uses the input file mode to correctly set the output file mode (previously it was hardcoded to 'w') when inplace=True is passed to its constructor.

bpo-36734 [https://bugs.python.org/issue?@action=redirect&bpo=36734]: Fix compilation of faulthandler.c on HP-UX. Initialize stack_t current_stack to zero using memset().

bpo-13611 [https://bugs.python.org/issue?@action=redirect&bpo=13611]: The xml.etree.ElementTree packages gained support for C14N 2.0 serialisation. Patch by Stefan Behnel.

bpo-36669 [https://bugs.python.org/issue?@action=redirect&bpo=36669]: Add missing matrix multiplication operator support to weakref.proxy.

bpo-36676 [https://bugs.python.org/issue?@action=redirect&bpo=36676]: The XMLParser() in xml.etree.ElementTree provides namespace prefix context to the parser target if it defines the callback methods “start_ns()” and/or “end_ns()”. Patch by Stefan Behnel.

bpo-36673 [https://bugs.python.org/issue?@action=redirect&bpo=36673]: The TreeBuilder and XMLPullParser in xml.etree.ElementTree gained support for parsing comments and processing instructions. Patch by Stefan Behnel.

bpo-36650 [https://bugs.python.org/issue?@action=redirect&bpo=36650]: The C version of functools.lru_cache() was treating calls with an empty **kwargs dictionary as being distinct from calls with no keywords at all. This did not result in an incorrect answer, but it did trigger an unexpected cache miss.

bpo-28552 [https://bugs.python.org/issue?@action=redirect&bpo=28552]: Fix distutils.sysconfig if sys.executable is None or an empty string: use os.getcwd() to initialize project_base. Fix also the distutils build command: don’t use sys.executable if it is None or an empty string.

bpo-35755 [https://bugs.python.org/issue?@action=redirect&bpo=35755]: shutil.which() and distutils.spawn.find_executable now use os.confstr("CS_PATH") if available instead of os.defpath, if the PATH environment variable is not set. Moreover, don’t use os.confstr("CS_PATH") nor os.defpath if the PATH environment variable is set to an empty string.

bpo-25430 [https://bugs.python.org/issue?@action=redirect&bpo=25430]: improve performance of IPNetwork.__contains__()

bpo-30485 [https://bugs.python.org/issue?@action=redirect&bpo=30485]: Path expressions in xml.etree.ElementTree can now avoid explicit namespace prefixes for tags (or the “{namespace}tag” notation) by passing a default namespace with an empty string prefix.

bpo-36613 [https://bugs.python.org/issue?@action=redirect&bpo=36613]: Fix asyncio wait() not removing callback if exception

bpo-36598 [https://bugs.python.org/issue?@action=redirect&bpo=36598]: Fix isinstance check for Mock objects with spec when the code is executed under tracing. Patch by Karthikeyan Singaravelan.

bpo-18748 [https://bugs.python.org/issue?@action=redirect&bpo=18748]: In development mode (-X dev) and in debug build, the io.IOBase destructor now logs close() exceptions. These exceptions are silent by default in release mode.

bpo-36575 [https://bugs.python.org/issue?@action=redirect&bpo=36575]: The _lsprof module now uses internal timer same to time.perf_counter() by default. gettimeofday(2) was used on Unix. New timer has better resolution on most Unix platforms and timings are no longer impacted by system clock updates since perf_counter() is monotonic. Patch by Inada Naoki.

bpo-33461 [https://bugs.python.org/issue?@action=redirect&bpo=33461]: json.loads now emits DeprecationWarning when encoding option is specified. Patch by Matthias Bussonnier.

bpo-36559 [https://bugs.python.org/issue?@action=redirect&bpo=36559]: The random module now prefers the lean internal _sha512 module over hashlib for seed(version=2) to optimize import time.

bpo-17561 [https://bugs.python.org/issue?@action=redirect&bpo=17561]: Set backlog=None as the default for socket.create_server.

bpo-34373 [https://bugs.python.org/issue?@action=redirect&bpo=34373]: Fix time.mktime() error handling on AIX for year before 1970.

bpo-36232 [https://bugs.python.org/issue?@action=redirect&bpo=36232]: Improve error message when trying to open existing DBM database that actually doesn’t exist. Patch by Marco Rougeth.

bpo-36546 [https://bugs.python.org/issue?@action=redirect&bpo=36546]: Add statistics.quantiles()

bpo-36050 [https://bugs.python.org/issue?@action=redirect&bpo=36050]: Optimized http.client.HTTPResponse.read() for large response. Patch by Inada Naoki.

bpo-36522 [https://bugs.python.org/issue?@action=redirect&bpo=36522]: If debuglevel is set to >0 in http.client, print all values for headers with multiple values for the same header name. Patch by Matt Houglum.

bpo-36492 [https://bugs.python.org/issue?@action=redirect&bpo=36492]: Deprecated passing required arguments like func as keyword arguments in functions which should accept arbitrary keyword arguments and pass them to other function. Arbitrary keyword arguments (even with names “self” and “func”) can now be passed to these functions if the required arguments are passed as positional arguments.

bpo-27181 [https://bugs.python.org/issue?@action=redirect&bpo=27181]: Add statistics.geometric_mean().

bpo-30427 [https://bugs.python.org/issue?@action=redirect&bpo=30427]: os.path.normcase() relies on os.fspath() to check the type of its argument. Redundant checks have been removed from its posixpath.normcase() and ntpath.normcase() implementations. Patch by Wolfgang Maier.

bpo-36385 [https://bugs.python.org/issue?@action=redirect&bpo=36385]: Stop rejecting IPv4 octets for being ambiguously octal. Leading zeros are ignored, and no longer are assumed to specify octal octets. Octets are always decimal numbers. Octets must still be no more than three digits, including leading zeroes.

bpo-36434 [https://bugs.python.org/issue?@action=redirect&bpo=36434]: Errors during writing to a ZIP file no longer prevent to properly close it.

bpo-36407 [https://bugs.python.org/issue?@action=redirect&bpo=36407]: Fixed wrong indentation writing for CDATA section in xml.dom.minidom. Patch by Vladimir Surjaninov.

bpo-36326 [https://bugs.python.org/issue?@action=redirect&bpo=36326]: inspect.getdoc() can now find docstrings for member objects when __slots__ is a dictionary.

bpo-36366 [https://bugs.python.org/issue?@action=redirect&bpo=36366]: Calling stop() on an unstarted or stopped unittest.mock.patch() object will now return None instead of raising RuntimeError, making the method idempotent. Patch by Karthikeyan Singaravelan.

bpo-36348 [https://bugs.python.org/issue?@action=redirect&bpo=36348]: The imap.IMAP4.logout() method no longer ignores silently arbitrary exceptions.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Add time module support and fix test_time failures for VxWorks.

bpo-36227 [https://bugs.python.org/issue?@action=redirect&bpo=36227]: Added support for keyword arguments default_namespace and xml_declaration in functions ElementTree.tostring() and ElementTree.tostringlist().

bpo-36004 [https://bugs.python.org/issue?@action=redirect&bpo=36004]: Added new alternate constructors datetime.date.fromisocalendar() and datetime.datetime.fromisocalendar(), which construct date objects from ISO year, week number and weekday; these are the inverse of each class’s isocalendar method. Patch by Paul Ganssle.

bpo-35936 [https://bugs.python.org/issue?@action=redirect&bpo=35936]: modulefinder no longer depends on the deprecated imp module, and the initializer for modulefinder.ModuleFinder now has immutable default arguments. Patch by Brandt Bucher.

bpo-35376 [https://bugs.python.org/issue?@action=redirect&bpo=35376]: modulefinder correctly handles modules that have the same name as a bad package. Patch by Brandt Bucher.

bpo-17396 [https://bugs.python.org/issue?@action=redirect&bpo=17396]: modulefinder no longer crashes when encountering syntax errors in followed imports. Patch by Brandt Bucher.

bpo-35934 [https://bugs.python.org/issue?@action=redirect&bpo=35934]: Added create_server() and has_dualstack_ipv6() convenience functions to automate the necessary tasks usually involved when creating a server socket, including accepting both IPv4 and IPv6 connections on the same socket. (Contributed by Giampaolo Rodola in bpo-17561 [https://bugs.python.org/issue?@action=redirect&bpo=17561].)

bpo-23078 [https://bugs.python.org/issue?@action=redirect&bpo=23078]: Add support for classmethod() and staticmethod() to unittest.mock.create_autospec(). Initial patch by Felipe Ochoa.

bpo-35416 [https://bugs.python.org/issue?@action=redirect&bpo=35416]: Fix potential resource warnings in distutils. Patch by Mickaël Schoentgen.

bpo-25451 [https://bugs.python.org/issue?@action=redirect&bpo=25451]: Add transparency methods to tkinter.PhotoImage. Patch by Zackery Spytz.

bpo-35082 [https://bugs.python.org/issue?@action=redirect&bpo=35082]: Don’t return deleted attributes when calling dir on a unittest.mock.Mock.

bpo-34547 [https://bugs.python.org/issue?@action=redirect&bpo=34547]: wsgiref.handlers.BaseHandler now handles abrupt client connection terminations gracefully. Patch by Petter Strandmark.

bpo-31658 [https://bugs.python.org/issue?@action=redirect&bpo=31658]: xml.sax.parse() now supports path-like. Patch by Mickaël Schoentgen.

bpo-34139 [https://bugs.python.org/issue?@action=redirect&bpo=34139]: Remove stale unix datagram socket before binding

bpo-33530 [https://bugs.python.org/issue?@action=redirect&bpo=33530]: Implemented Happy Eyeballs in asyncio.create_connection(). Added two new arguments, happy_eyeballs_delay and interleave, to specify Happy Eyeballs behavior.

bpo-33291 [https://bugs.python.org/issue?@action=redirect&bpo=33291]: Do not raise AttributeError when calling the inspect functions isgeneratorfunction, iscoroutinefunction, isasyncgenfunction on a method created from an arbitrary callable. Instead, return False.

bpo-31310 [https://bugs.python.org/issue?@action=redirect&bpo=31310]: Fix the multiprocessing.semaphore_tracker so it is reused by child processes

bpo-31292 [https://bugs.python.org/issue?@action=redirect&bpo=31292]: Fix setup.py check --restructuredtext for files containing include directives.

Documentation

bpo-36625 [https://bugs.python.org/issue?@action=redirect&bpo=36625]: Remove obsolete comments from docstrings in fractions.Fraction

bpo-30840 [https://bugs.python.org/issue?@action=redirect&bpo=30840]: Document relative imports

bpo-36523 [https://bugs.python.org/issue?@action=redirect&bpo=36523]: Add docstring for io.IOBase.writelines().

bpo-36425 [https://bugs.python.org/issue?@action=redirect&bpo=36425]: New documentation translation: Simplified Chinese [https://docs.python.org/zh-cn/].

bpo-36345 [https://bugs.python.org/issue?@action=redirect&bpo=36345]: Avoid the duplication of code from Tools/scripts/serve.py in using the literalinclude directive for the basic wsgiref-based web server in the documentation of wsgiref. Contributed by Stéphane Wirtel.

bpo-36345 [https://bugs.python.org/issue?@action=redirect&bpo=36345]: Using the code of the Tools/scripts/serve.py script as an example in the wsgiref documentation. Contributed by Stéphane Wirtel.

bpo-36157 [https://bugs.python.org/issue?@action=redirect&bpo=36157]: Added documentation for PyInterpreterState_Main().

bpo-33043 [https://bugs.python.org/issue?@action=redirect&bpo=33043]: Updates the docs.python.org page with the addition of a ‘Contributing to Docs’ link at the end of the page (between ‘Reporting Bugs’ and ‘About Documentation’). Updates the ‘Found a Bug’ page with additional links and information in the Documentation Bugs section.

bpo-35581 [https://bugs.python.org/issue?@action=redirect&bpo=35581]: @typing.type_check_only now allows type stubs to mark functions and classes not available during runtime.

bpo-33832 [https://bugs.python.org/issue?@action=redirect&bpo=33832]: Add glossary entry for ‘magic method’.

bpo-32913 [https://bugs.python.org/issue?@action=redirect&bpo=32913]: Added re.Match.groupdict example to regex HOWTO.

Tests

bpo-36719 [https://bugs.python.org/issue?@action=redirect&bpo=36719]: regrtest now always detects uncollectable objects. Previously, the check was only enabled by --findleaks. The check now also works with -jN/--multiprocess N. --findleaks becomes a deprecated alias to --fail-env-changed.

bpo-36725 [https://bugs.python.org/issue?@action=redirect&bpo=36725]: When using multiprocessing mode (-jN), regrtest now better reports errors if a worker process fails, and it exits immediately on a worker thread failure or when interrupted.

bpo-36454 [https://bugs.python.org/issue?@action=redirect&bpo=36454]: Change test_time.test_monotonic() to test only the lower bound of elapsed time after a sleep command rather than the upper bound. This prevents unnecessary test failures on slow buildbots. Patch by Victor Stinner.

bpo-32424 [https://bugs.python.org/issue?@action=redirect&bpo=32424]: Improve test coverage for xml.etree.ElementTree. Patch by Gordon P. Hemsley.

bpo-32424 [https://bugs.python.org/issue?@action=redirect&bpo=32424]: Fix typo in test_cyclic_gc() test for xml.etree.ElementTree. Patch by Gordon P. Hemsley.

bpo-36635 [https://bugs.python.org/issue?@action=redirect&bpo=36635]: Add a new _testinternalcapi module to test the internal C API.

bpo-36629 [https://bugs.python.org/issue?@action=redirect&bpo=36629]: Fix test_imap4_host_default_value() of test_imaplib: catch also errno.ENETUNREACH error.

bpo-36611 [https://bugs.python.org/issue?@action=redirect&bpo=36611]: Fix test_sys.test_getallocatedblocks() when tracemalloc is enabled.

bpo-36560 [https://bugs.python.org/issue?@action=redirect&bpo=36560]: Fix reference leak hunting in regrtest: compute also deltas (of reference count, allocated memory blocks, file descriptor count) during warmup, to ensure that everything is initialized before starting to hunt reference leaks.

bpo-36565 [https://bugs.python.org/issue?@action=redirect&bpo=36565]: Fix reference hunting (python3 -m test -R 3:3) when Python has no built-in abc module.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Port test_resource to VxWorks: skip tests cases setting RLIMIT_FSIZE and RLIMIT_CPU.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix test_tabnanny on VxWorks: adjust ENOENT error message.

bpo-36436 [https://bugs.python.org/issue?@action=redirect&bpo=36436]: Fix _testcapi.pymem_buffer_overflow(): handle memory allocation failure.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Fix test_utf8_mode on VxWorks: Python always use UTF-8 on VxWorks.

bpo-36341 [https://bugs.python.org/issue?@action=redirect&bpo=36341]: Fix tests that may fail with PermissionError upon calling bind() on AF_UNIX sockets.

Build

bpo-36747 [https://bugs.python.org/issue?@action=redirect&bpo=36747]: Remove the stale scriptsinstall Makefile target.

bpo-21536 [https://bugs.python.org/issue?@action=redirect&bpo=21536]: On Unix, C extensions are no longer linked to libpython except on Android and Cygwin.

It is now possible for a statically linked Python to load a C extension built using a shared library Python.

When Python is embedded, libpython must not be loaded with RTLD_LOCAL, but RTLD_GLOBAL instead. Previously, using RTLD_LOCAL, it was already not possible to load C extensions which were not linked to libpython, such as C extensions of the standard library built by the *shared* section of Modules/Setup.

distutils, python-config and python-config.py have been modified.

bpo-36707 [https://bugs.python.org/issue?@action=redirect&bpo=36707]: ./configure --with-pymalloc no longer adds the m flag to SOABI (sys.implementation.cache_tag). Enabling or disabling pymalloc has no impact on the ABI.

bpo-36635 [https://bugs.python.org/issue?@action=redirect&bpo=36635]: Change PyAPI_FUNC(type), PyAPI_DATA(type) and PyMODINIT_FUNC macros of pyport.h when Py_BUILD_CORE_MODULE is defined. The Py_BUILD_CORE_MODULE define must be now be used to build a C extension as a dynamic library accessing Python internals: export the PyInit_xxx() function in DLL exports on Windows.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Don’t build the _crypt extension on VxWorks.

bpo-36618 [https://bugs.python.org/issue?@action=redirect&bpo=36618]: Add -fmax-type-align=8 to CFLAGS when clang compiler is detected. The pymalloc memory allocator aligns memory on 8 bytes. On x86-64, clang expects alignment on 16 bytes by default and so uses MOVAPS instruction which can lead to segmentation fault. Instruct clang that Python is limited to alignment on 8 bytes to use MOVUPS instruction instead: slower but don’t trigger a SIGSEGV if the memory is not aligned on 16 bytes. Sadly, the flag must be added to CFLAGS and not just CFLAGS_NODIST, since third party C extensions can have the same issue.

bpo-36605 [https://bugs.python.org/issue?@action=redirect&bpo=36605]: make tags and make TAGS now also parse Modules/_io/*.c and Modules/_io/*.h.

bpo-36465 [https://bugs.python.org/issue?@action=redirect&bpo=36465]: Release builds and debug builds are now ABI compatible: defining the Py_DEBUG macro no longer implies the Py_TRACE_REFS macro, which introduces the only ABI incompatibility. The Py_TRACE_REFS macro, which adds the sys.getobjects() function and the PYTHONDUMPREFS environment variable, can be set using the new ./configure --with-trace-refs build option.

bpo-36577 [https://bugs.python.org/issue?@action=redirect&bpo=36577]: setup.py now correctly reports missing OpenSSL headers and libraries again.

bpo-36544 [https://bugs.python.org/issue?@action=redirect&bpo=36544]: Fix regression introduced in bpo-36146 [https://bugs.python.org/issue?@action=redirect&bpo=36146] refactoring setup.py

bpo-36508 [https://bugs.python.org/issue?@action=redirect&bpo=36508]: python-config --ldflags no longer includes flags of the LINKFORSHARED variable. The LINKFORSHARED variable must only be used to build executables.

bpo-36503 [https://bugs.python.org/issue?@action=redirect&bpo=36503]: Remove references to “aix3” and “aix4”. Patch by M. Felt.

Windows

bpo-35920 [https://bugs.python.org/issue?@action=redirect&bpo=35920]: Added platform.win32_edition() and platform.win32_is_iot(). Added support for cross-compiling packages for Windows ARM32. Skip tests that are not expected to work on Windows IoT Core ARM32.

bpo-36649 [https://bugs.python.org/issue?@action=redirect&bpo=36649]: Remove trailing spaces for registry keys when installed via the Store.

bpo-34144 [https://bugs.python.org/issue?@action=redirect&bpo=34144]: Fixed activate.bat to correctly update codepage when chcp.com returns dots in output. Patch by Lorenz Mende.

bpo-36509 [https://bugs.python.org/issue?@action=redirect&bpo=36509]: Added preset-iot layout for Windows IoT ARM containers. This layout doesn’t contain UI components like tkinter or IDLE. It also doesn’t contain files to support on-target builds since Windows ARM32 builds must be cross-compiled when using MSVC.

bpo-35941 [https://bugs.python.org/issue?@action=redirect&bpo=35941]: enum_certificates function of the ssl module now returns certificates from all available certificate stores inside windows in a query instead of returning only certificates from the system wide certificate store. This includes certificates from these certificate stores: local machine, local machine enterprise, local machine group policy, current user, current user group policy, services, users. ssl.enum_crls() function is changed in the same way to return all certificate revocation lists inside the windows certificate revocation list stores.

bpo-36441 [https://bugs.python.org/issue?@action=redirect&bpo=36441]: Fixes creating a venv when debug binaries are installed.

bpo-36085 [https://bugs.python.org/issue?@action=redirect&bpo=36085]: Enable better DLL resolution on Windows by using safe DLL search paths and adding os.add_dll_directory().

bpo-36010 [https://bugs.python.org/issue?@action=redirect&bpo=36010]: Add the venv standard library module to the nuget distribution for Windows.

bpo-29515 [https://bugs.python.org/issue?@action=redirect&bpo=29515]: Add the following socket module constants on Windows: IPPROTO_AH IPPROTO_CBT IPPROTO_DSTOPTS IPPROTO_EGP IPPROTO_ESP IPPROTO_FRAGMENT IPPROTO_GGP IPPROTO_HOPOPTS IPPROTO_ICLFXBM IPPROTO_ICMPV6 IPPROTO_IDP IPPROTO_IGMP IPPROTO_IGP IPPROTO_IPV4 IPPROTO_IPV6 IPPROTO_L2TP IPPROTO_MAX IPPROTO_ND IPPROTO_NONE IPPROTO_PGM IPPROTO_PIM IPPROTO_PUP IPPROTO_RDP IPPROTO_ROUTING IPPROTO_SCTP IPPROTO_ST

bpo-35947 [https://bugs.python.org/issue?@action=redirect&bpo=35947]: Added current version of libffi to cpython-source-deps. Change _ctypes to use current version of libffi on Windows.

bpo-34060 [https://bugs.python.org/issue?@action=redirect&bpo=34060]: Report system load when running test suite on Windows. Patch by Ammar Askar. Based on prior work by Jeremy Kloth.

bpo-31512 [https://bugs.python.org/issue?@action=redirect&bpo=31512]: With the Windows 10 Creators Update, non-elevated users can now create symlinks as long as the computer has Developer Mode enabled.

macOS

bpo-34602 [https://bugs.python.org/issue?@action=redirect&bpo=34602]: Avoid failures setting macOS stack resource limit with resource.setrlimit. This reverts an earlier fix for bpo-18075 [https://bugs.python.org/issue?@action=redirect&bpo=18075] which forced a non-default stack size when building the interpreter executable on macOS.

IDLE

bpo-36429 [https://bugs.python.org/issue?@action=redirect&bpo=36429]: Fix starting IDLE with pyshell. Add idlelib.pyshell alias at top; remove pyshell alias at bottom. Remove obsolete __name__==’__main__’ command.

Tools/Demos

bpo-14546 [https://bugs.python.org/issue?@action=redirect&bpo=14546]: Fix the argument handling in Tools/scripts/lll.py.

C API

bpo-36763 [https://bugs.python.org/issue?@action=redirect&bpo=36763]: Fix memory leak in Py_SetStandardStreamEncoding(): release memory if the function is called twice.

bpo-36641 [https://bugs.python.org/issue?@action=redirect&bpo=36641]: PyDoc_VAR(name) and PyDoc_STRVAR(name, str) now create static const char name[] instead of static char name[]. Patch by Inada Naoki.

bpo-36389 [https://bugs.python.org/issue?@action=redirect&bpo=36389]: Change the value of CLEANBYTE, DEADDYTE and FORBIDDENBYTE internal constants used by debug hooks on Python memory allocators (PyMem_SetupDebugHooks() function). Byte patterns 0xCB, 0xDB and 0xFB have been replaced with 0xCD, 0xDD and 0xFD to use the same values than Windows CRT debug malloc() and free().

bpo-36443 [https://bugs.python.org/issue?@action=redirect&bpo=36443]: Since Python 3.7.0, calling Py_DecodeLocale() before Py_Initialize() produces mojibake if the LC_CTYPE locale is coerced and/or if the UTF-8 Mode is enabled by the user configuration. The LC_CTYPE coercion and UTF-8 Mode are now disabled by default to fix the mojibake issue. They must now be enabled explicitly (opt-in) using the new _Py_PreInitialize() API with _PyPreConfig.

bpo-36025 [https://bugs.python.org/issue?@action=redirect&bpo=36025]: Fixed an accidental change to the datetime C API where the arguments to the PyDate_FromTimestamp() function were incorrectly interpreted as a single timestamp rather than an arguments tuple, which causes existing code to start raising TypeError. The backwards-incompatible change was only present in alpha releases of Python 3.8. Patch by Paul Ganssle.

bpo-35810 [https://bugs.python.org/issue?@action=redirect&bpo=35810]: Modify PyObject_Init to correctly increase the refcount of heap-allocated Type objects. Also fix the refcounts of the heap-allocated types that were either doing this manually or not decreasing the type’s refcount in tp_dealloc

Python 3.8.0 alpha 3

Release date: 2019-03-25

Security

bpo-36216 [https://bugs.python.org/issue?@action=redirect&bpo=36216]: Changes urlsplit() to raise ValueError when the URL contains characters that decompose under IDNA encoding (NFKC-normalization) into characters that affect how the URL is parsed.

bpo-35121 [https://bugs.python.org/issue?@action=redirect&bpo=35121]: Don’t send cookies of domain A without Domain attribute to domain B when domain A is a suffix match of domain B while using a cookiejar with http.cookiejar.DefaultCookiePolicy policy. Patch by Karthikeyan Singaravelan.

Core and Builtins

bpo-36421 [https://bugs.python.org/issue?@action=redirect&bpo=36421]: Fix a possible double decref in _ctypes.c’s PyCArrayType_new().

bpo-36412 [https://bugs.python.org/issue?@action=redirect&bpo=36412]: Fix a possible crash when creating a new dictionary.

bpo-36398 [https://bugs.python.org/issue?@action=redirect&bpo=36398]: Fix a possible crash in structseq_repr().

bpo-36256 [https://bugs.python.org/issue?@action=redirect&bpo=36256]: Fix bug in parsermodule when parsing a state in a DFA that has two or more arcs with labels of the same type. Patch by Pablo Galindo.

bpo-36365 [https://bugs.python.org/issue?@action=redirect&bpo=36365]: repr(structseq) is no longer limited to 512 bytes.

bpo-36374 [https://bugs.python.org/issue?@action=redirect&bpo=36374]: Fix a possible null pointer dereference in merge_consts_recursive(). Patch by Zackery Spytz.

bpo-36236 [https://bugs.python.org/issue?@action=redirect&bpo=36236]: At Python initialization, the current directory is no longer prepended to sys.path if it has been removed.

bpo-36352 [https://bugs.python.org/issue?@action=redirect&bpo=36352]: Python initialization now fails with an error, rather than silently truncating paths, if a path is too long.

bpo-36301 [https://bugs.python.org/issue?@action=redirect&bpo=36301]: Python initialization now fails if decoding pybuilddir.txt configuration file fails at startup.

bpo-36333 [https://bugs.python.org/issue?@action=redirect&bpo=36333]: Fix leak in _PyRuntimeState_Fini. Contributed by Stéphane Wirtel.

bpo-36332 [https://bugs.python.org/issue?@action=redirect&bpo=36332]: The builtin compile() can now handle AST objects that contain assignment expressions. Patch by Pablo Galindo.

bpo-36282 [https://bugs.python.org/issue?@action=redirect&bpo=36282]: Improved error message for too much positional arguments in some builtin functions.

bpo-30040 [https://bugs.python.org/issue?@action=redirect&bpo=30040]: New empty dict uses fewer memory for now. It used more memory than empty dict created by dict.clear(). And empty dict creation and deletion is about 2x faster. Patch by Inada Naoki.

bpo-36262 [https://bugs.python.org/issue?@action=redirect&bpo=36262]: Fix an unlikely memory leak on conversion from string to float in the function _Py_dg_strtod() used by float(str), complex(str), pickle.load(), marshal.load(), etc.

bpo-36252 [https://bugs.python.org/issue?@action=redirect&bpo=36252]: Update Unicode databases to version 12.0.0.

bpo-36218 [https://bugs.python.org/issue?@action=redirect&bpo=36218]: Fix a segfault occurring when sorting a list of heterogeneous values. Patch contributed by Rémi Lapeyre and Elliot Gorokhovsky.

bpo-36188 [https://bugs.python.org/issue?@action=redirect&bpo=36188]: Cleaned up left-over vestiges of Python 2 unbound method handling in method objects and documentation. Patch by Martijn Pieters

bpo-36124 [https://bugs.python.org/issue?@action=redirect&bpo=36124]: Add a new interpreter-specific dict and expose it in the C-API via PyInterpreterState_GetDict(). This parallels PyThreadState_GetDict(). However, extension modules should continue using PyModule_GetState() for their own internal per-interpreter state.

bpo-35975 [https://bugs.python.org/issue?@action=redirect&bpo=35975]: Add a feature_version flag to ast.parse() (documented) and compile() (hidden) that allows tweaking the parser to support older versions of the grammar. In particular, if feature_version is 5 or 6, the hacks for the async and await keyword from PEP 492 are reinstated. (For 7 or higher, these are unconditionally treated as keywords, but they are still special tokens rather than NAME tokens that the parser driver recognizes.)

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Use UTF-8 as the system encoding on VxWorks.

bpo-36048 [https://bugs.python.org/issue?@action=redirect&bpo=36048]: The __index__() special method will be used instead of __int__() for implicit conversion of Python numbers to C integers. Using the __int__() method in implicit conversions has been deprecated.

bpo-35808 [https://bugs.python.org/issue?@action=redirect&bpo=35808]: Retire pgen and use a modified version of pgen2 to generate the parser. Patch by Pablo Galindo.

Library

bpo-36401 [https://bugs.python.org/issue?@action=redirect&bpo=36401]: The class documentation created by pydoc now has a separate section for readonly properties.

bpo-36320 [https://bugs.python.org/issue?@action=redirect&bpo=36320]: The typing.NamedTuple() class has deprecated the _field_types attribute in favor of the __annotations__ attribute which carried the same information. Also, both attributes were converted from OrderedDict to a regular dict.

bpo-34745 [https://bugs.python.org/issue?@action=redirect&bpo=34745]: Fix asyncio ssl memory issues caused by circular references

bpo-36324 [https://bugs.python.org/issue?@action=redirect&bpo=36324]: Add method to statistics.NormalDist for computing the inverse cumulative normal distribution.

bpo-36321 [https://bugs.python.org/issue?@action=redirect&bpo=36321]: collections.namedtuple() misspelled the name of an attribute. To be consistent with typing.NamedTuple, the attribute name should have been “_field_defaults” instead of “_fields_defaults”. For backwards compatibility, both spellings are now created. The misspelled version may be removed in the future.

bpo-36297 [https://bugs.python.org/issue?@action=redirect&bpo=36297]: “unicode_internal” codec is removed. It was deprecated since Python 3.3. Patch by Inada Naoki.

bpo-36298 [https://bugs.python.org/issue?@action=redirect&bpo=36298]: Raise ModuleNotFoundError in pyclbr when a module can’t be found. Thanks to ‘mental’ for the bug report.

bpo-36268 [https://bugs.python.org/issue?@action=redirect&bpo=36268]: Switch the default format used for writing tars with tarfile to the modern POSIX.1-2001 pax standard, from the vendor-specific GNU. Contributed by C.A.M. Gerlach.

bpo-36285 [https://bugs.python.org/issue?@action=redirect&bpo=36285]: Fix integer overflows in the array module. Patch by Stephan Hohe.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Add _signal module support for VxWorks.

bpo-36272 [https://bugs.python.org/issue?@action=redirect&bpo=36272]: logging does not silently ignore RecursionError anymore. Patch contributed by Rémi Lapeyre.

bpo-36280 [https://bugs.python.org/issue?@action=redirect&bpo=36280]: Add a kind field to ast.Constant. It is ‘u’ if the literal has a ‘u’ prefix (i.e. a Python 2 style unicode literal), else None.

bpo-35931 [https://bugs.python.org/issue?@action=redirect&bpo=35931]: The pdb debug command now gracefully handles all exceptions.

bpo-36251 [https://bugs.python.org/issue?@action=redirect&bpo=36251]: Fix format strings used for stderrprinter and re.Match reprs. Patch by Stephan Hohe.

bpo-36235 [https://bugs.python.org/issue?@action=redirect&bpo=36235]: Fix CFLAGS in customize_compiler() of distutils.sysconfig: when the CFLAGS environment variable is defined, don’t override CFLAGS variable with the OPT variable anymore. Initial patch written by David Malcolm.

bpo-35807 [https://bugs.python.org/issue?@action=redirect&bpo=35807]: Update ensurepip to install pip 19.0.3 and setuptools 40.8.0.

bpo-36139 [https://bugs.python.org/issue?@action=redirect&bpo=36139]: Release GIL when closing mmap objects.

bpo-36179 [https://bugs.python.org/issue?@action=redirect&bpo=36179]: Fix two unlikely reference leaks in _hashopenssl. The leaks only occur in out-of-memory cases.

bpo-36169 [https://bugs.python.org/issue?@action=redirect&bpo=36169]: Add overlap() method to statistics.NormalDist. Computes the overlapping coefficient for two normal distributions.

bpo-36103 [https://bugs.python.org/issue?@action=redirect&bpo=36103]: Default buffer size used by shutil.copyfileobj() is changed from 16 KiB to 64 KiB on non-Windows platform to reduce system call overhead. Contributed by Inada Naoki.

bpo-36130 [https://bugs.python.org/issue?@action=redirect&bpo=36130]: Fix pdb with skip=... when stepping into a frame without a __name__ global. Patch by Anthony Sottile.

bpo-35652 [https://bugs.python.org/issue?@action=redirect&bpo=35652]: shutil.copytree(copy_function=…) erroneously pass DirEntry instead of a path string.

bpo-35178 [https://bugs.python.org/issue?@action=redirect&bpo=35178]: Ensure custom warnings.formatwarning() function can receive line as positional argument. Based on patch by Tashrif Billah.

bpo-36106 [https://bugs.python.org/issue?@action=redirect&bpo=36106]: Resolve potential name clash with libm’s sinpi(). Patch by Dmitrii Pasechnik.

bpo-36091 [https://bugs.python.org/issue?@action=redirect&bpo=36091]: Clean up reference to async generator in Lib/types. Patch by Henry Chen.

bpo-36043 [https://bugs.python.org/issue?@action=redirect&bpo=36043]: FileCookieJar supports path-like object. Contributed by Stéphane Wirtel

bpo-35899 [https://bugs.python.org/issue?@action=redirect&bpo=35899]: Enum has been fixed to correctly handle empty strings and strings with non-Latin characters (ie. ‘α’, ‘א’) without crashing. Original patch contributed by Maxwell. Assisted by Stéphane Wirtel.

bpo-21269 [https://bugs.python.org/issue?@action=redirect&bpo=21269]: Add args and kwargs properties to mock call objects. Contributed by Kumar Akshay.

bpo-30670 [https://bugs.python.org/issue?@action=redirect&bpo=30670]: pprint.pp has been added to pretty-print objects with dictionary keys being sorted with their insertion order by default. Parameter sort_dicts has been added to pprint.pprint, pprint.pformat and pprint.PrettyPrinter. Contributed by Rémi Lapeyre.

bpo-35843 [https://bugs.python.org/issue?@action=redirect&bpo=35843]: Implement __getitem__ for _NamespacePath. Patch by Anthony Sottile.

bpo-35802 [https://bugs.python.org/issue?@action=redirect&bpo=35802]: Clean up code which checked presence of os.stat / os.lstat / os.chmod which are always present. Patch by Anthony Sottile.

bpo-35715 [https://bugs.python.org/issue?@action=redirect&bpo=35715]: Librates the return value of a ProcessPoolExecutor _process_worker after it’s no longer needed to free memory

bpo-35493 [https://bugs.python.org/issue?@action=redirect&bpo=35493]: Use multiprocessing.connection.wait() instead of polling each 0.2 seconds for worker updates in multiprocessing.Pool. Patch by Pablo Galindo.

bpo-35661 [https://bugs.python.org/issue?@action=redirect&bpo=35661]: Store the venv prompt in pyvenv.cfg.

bpo-35121 [https://bugs.python.org/issue?@action=redirect&bpo=35121]: Don’t set cookie for a request when the request path is a prefix match of the cookie’s path attribute but doesn’t end with “/”. Patch by Karthikeyan Singaravelan.

bpo-21478 [https://bugs.python.org/issue?@action=redirect&bpo=21478]: Calls to a child function created with unittest.mock.create_autospec() should propagate to the parent. Patch by Karthikeyan Singaravelan.

bpo-35198 [https://bugs.python.org/issue?@action=redirect&bpo=35198]: Fix C++ extension compilation on AIX

Documentation

bpo-36329 [https://bugs.python.org/issue?@action=redirect&bpo=36329]: Declare the path of the Python binary for the usage of Tools/scripts/serve.py when executing make -C Doc/ serve. Contributed by Stéphane Wirtel

bpo-36138 [https://bugs.python.org/issue?@action=redirect&bpo=36138]: Improve documentation about converting datetime.timedelta to scalars.

bpo-21314 [https://bugs.python.org/issue?@action=redirect&bpo=21314]: A new entry was added to the Core Language Section of the Programming FAQ, which explaines the usage of slash(/) in the signature of a function. Patch by Lysandros Nikolaou

Tests

bpo-36234 [https://bugs.python.org/issue?@action=redirect&bpo=36234]: test_posix.PosixUidGidTests: add tests for invalid uid/gid type (str). Initial patch written by David Malcolm.

bpo-29571 [https://bugs.python.org/issue?@action=redirect&bpo=29571]: Fix test_re.test_locale_flag(): use locale.getpreferredencoding() rather than locale.getlocale() to get the locale encoding. With some locales, locale.getlocale() returns the wrong encoding.

bpo-36123 [https://bugs.python.org/issue?@action=redirect&bpo=36123]: Fix race condition in test_socket.

Build

bpo-36356 [https://bugs.python.org/issue?@action=redirect&bpo=36356]: Fix leaks that led to build failure when configured with address sanitizer.

bpo-36146 [https://bugs.python.org/issue?@action=redirect&bpo=36146]: Add TEST_EXTENSIONS constant to setup.py to allow to not build test extensions like _testcapi.

bpo-36146 [https://bugs.python.org/issue?@action=redirect&bpo=36146]: Fix setup.py on macOS: only add /usr/include/ffi to include directories of _ctypes, not for all extensions.

bpo-31904 [https://bugs.python.org/issue?@action=redirect&bpo=31904]: Enable build system to cross-build for VxWorks RTOS.

Windows

bpo-36312 [https://bugs.python.org/issue?@action=redirect&bpo=36312]: Fixed decoders for the following code pages: 50220, 50221, 50222, 50225, 50227, 50229, 57002 through 57011, 65000 and 42.

bpo-36264 [https://bugs.python.org/issue?@action=redirect&bpo=36264]: Don’t honor POSIX HOME in os.path.expanduser on windows. Patch by Anthony Sottile.

bpo-24643 [https://bugs.python.org/issue?@action=redirect&bpo=24643]: Fix name collisions due to #define timezone _timezone in PC/pyconfig.h.

IDLE

bpo-36405 [https://bugs.python.org/issue?@action=redirect&bpo=36405]: Use dict unpacking in idlelib.

bpo-36396 [https://bugs.python.org/issue?@action=redirect&bpo=36396]: Remove fgBg param of idlelib.config.GetHighlight(). This param was only used twice and changed the return type.

bpo-36176 [https://bugs.python.org/issue?@action=redirect&bpo=36176]: Fix IDLE autocomplete & calltip popup colors. Prevent conflicts with Linux dark themes (and slightly darken calltip background).

bpo-23205 [https://bugs.python.org/issue?@action=redirect&bpo=23205]: For the grep module, add tests for findfiles, refactor findfiles to be a module-level function, and refactor findfiles to use os.walk.

bpo-23216 [https://bugs.python.org/issue?@action=redirect&bpo=23216]: Add docstrings to IDLE search modules.

bpo-36152 [https://bugs.python.org/issue?@action=redirect&bpo=36152]: Remove colorizer.ColorDelegator.close_when_done and the corresponding argument of .close(). In IDLE, both have always been None or False since 2007.

bpo-32129 [https://bugs.python.org/issue?@action=redirect&bpo=32129]: Avoid blurry IDLE application icon on macOS with Tk 8.6. Patch by Kevin Walzer.

bpo-36096 [https://bugs.python.org/issue?@action=redirect&bpo=36096]: Refactor class variables to instance variables in colorizer.

bpo-30348 [https://bugs.python.org/issue?@action=redirect&bpo=30348]: Increase test coverage of idlelib.autocomplete by 30%. Patch by Louie Lu

Tools/Demos

bpo-35132 [https://bugs.python.org/issue?@action=redirect&bpo=35132]: Fix py-list and py-bt commands of python-gdb.py on gdb7.

bpo-32217 [https://bugs.python.org/issue?@action=redirect&bpo=32217]: Fix freeze script on Windows.

C API

bpo-36381 [https://bugs.python.org/issue?@action=redirect&bpo=36381]: Raise DeprecationWarning when ‘#’ formats are used for building or parsing values without PY_SSIZE_T_CLEAN.

bpo-36142 [https://bugs.python.org/issue?@action=redirect&bpo=36142]: The whole coreconfig.h header is now excluded from Py_LIMITED_API. Move functions definitions into a new internal pycore_coreconfig.h header.

Python 3.8.0 alpha 2

Release date: 2019-02-25

Core and Builtins

bpo-36052 [https://bugs.python.org/issue?@action=redirect&bpo=36052]: Raise a SyntaxError when assigning a value to __debug__ with the Assignment Operator. Contributed by Stéphane Wirtel and Pablo Galindo.

bpo-36012 [https://bugs.python.org/issue?@action=redirect&bpo=36012]: Doubled the speed of class variable writes. When a non-dunder attribute was updated, there was an unnecessary call to update slots.

bpo-35942 [https://bugs.python.org/issue?@action=redirect&bpo=35942]: The error message emitted when returning invalid types from __fspath__ in interfaces that allow passing PathLike objects has been improved and now it does explain the origin of the error.

bpo-36016 [https://bugs.python.org/issue?@action=redirect&bpo=36016]: gc.get_objects can now receive an optional parameter indicating a generation to get objects from. Patch by Pablo Galindo.

bpo-1054041 [https://bugs.python.org/issue?@action=redirect&bpo=1054041]: When the main interpreter exits due to an uncaught KeyboardInterrupt, the process now exits in the appropriate manner for its parent process to detect that a SIGINT or ^C terminated the process. This allows shells and batch scripts to understand that the user has asked them to stop.

bpo-35992 [https://bugs.python.org/issue?@action=redirect&bpo=35992]: Fix __class_getitem__() not being called on a class with a custom non-subscriptable metaclass.

bpo-35993 [https://bugs.python.org/issue?@action=redirect&bpo=35993]: Fix a crash on fork when using subinterpreters. Contributed by Stéphane Wirtel

bpo-35991 [https://bugs.python.org/issue?@action=redirect&bpo=35991]: Fix a potential double free in Modules/_randommodule.c.

bpo-35961 [https://bugs.python.org/issue?@action=redirect&bpo=35961]: Fix a crash in slice_richcompare(): use strong references rather than stolen references for the two temporary internal tuples.

bpo-35911 [https://bugs.python.org/issue?@action=redirect&bpo=35911]: Enable the creation of cell objects by adding a cell.__new__ method, and expose the type cell in Lib/types.py under the name CellType. Patch by Pierre Glaser.

bpo-12822 [https://bugs.python.org/issue?@action=redirect&bpo=12822]: Use monotonic clock for pthread_cond_timedwait when pthread_condattr_setclock and CLOCK_MONOTONIC are available.

bpo-15248 [https://bugs.python.org/issue?@action=redirect&bpo=15248]: The compiler emits now syntax warnings in the case when a comma is likely missed before tuple or list.

bpo-35886 [https://bugs.python.org/issue?@action=redirect&bpo=35886]: The implementation of PyInterpreterState has been moved into the internal header files (guarded by Py_BUILD_CORE).

bpo-31506 [https://bugs.python.org/issue?@action=redirect&bpo=31506]: Clarify the errors reported when object.__new__ and object.__init__ receive more than one argument. Contributed by Sanyam Khurana.

bpo-35724 [https://bugs.python.org/issue?@action=redirect&bpo=35724]: Signal-handling is now guaranteed to happen relative to the main interpreter.

bpo-33608 [https://bugs.python.org/issue?@action=redirect&bpo=33608]: We added a new internal _Py_AddPendingCall() that operates relative to the provided interpreter. This allows us to use the existing implementation to ask another interpreter to do work that cannot be done in the current interpreter, like decref an object the other interpreter owns. The existing Py_AddPendingCall() only operates relative to the main interpreter.

bpo-33989 [https://bugs.python.org/issue?@action=redirect&bpo=33989]: Fix a possible crash in list.sort() when sorting objects with ob_type->tp_richcompare == NULL. Patch by Zackery Spytz.

Library

bpo-35512 [https://bugs.python.org/issue?@action=redirect&bpo=35512]: unittest.mock.patch.dict() used as a decorator with string target resolves the target during function call instead of during decorator construction. Patch by Karthikeyan Singaravelan.

bpo-36018 [https://bugs.python.org/issue?@action=redirect&bpo=36018]: Add statistics.NormalDist, a tool for creating and manipulating normal distributions of random variable. Features a composite class that treats the mean and standard deviation of measurement data as single entity.

bpo-35904 [https://bugs.python.org/issue?@action=redirect&bpo=35904]: Added statistics.fmean() as a faster, floating-point variant of the existing mean() function.

bpo-35918 [https://bugs.python.org/issue?@action=redirect&bpo=35918]: Removed broken has_key method from multiprocessing.managers.SyncManager.dict. Contributed by Rémi Lapeyre.

bpo-18283 [https://bugs.python.org/issue?@action=redirect&bpo=18283]: Add support for bytes to shutil.which().

bpo-35960 [https://bugs.python.org/issue?@action=redirect&bpo=35960]: Fix dataclasses.field() throwing away empty mapping objects passed as metadata.

bpo-35500 [https://bugs.python.org/issue?@action=redirect&bpo=35500]: Write expected and actual call parameters on separate lines in unittest.mock.Mock.assert_called_with() assertion errors. Contributed by Susan Su.

bpo-35931 [https://bugs.python.org/issue?@action=redirect&bpo=35931]: The pdb debug command now gracefully handles syntax errors.

bpo-24209 [https://bugs.python.org/issue?@action=redirect&bpo=24209]: In http.server script, rely on getaddrinfo to bind to preferred address based on the bind parameter. Now default bind or binding to a name may bind to IPv6 or dual-stack, depending on the environment.

bpo-35321 [https://bugs.python.org/issue?@action=redirect&bpo=35321]: Set __spec__.origin of _frozen_importlib to frozen so that it matches the behavior of _frozen_importlib_external. Patch by Nina Zakharenko.

bpo-35378 [https://bugs.python.org/issue?@action=redirect&bpo=35378]: Fix a reference issue inside multiprocessing.Pool that caused the pool to remain alive if it was deleted without being closed or terminated explicitly. A new strong reference is added to the pool iterators to link the lifetime of the pool to the lifetime of its iterators so the pool does not get destroyed if a pool iterator is still alive.

bpo-34294 [https://bugs.python.org/issue?@action=redirect&bpo=34294]: re module, fix wrong capturing groups in rare cases. re.search(), re.findall(), re.sub() and other functions that scan through string looking for a match, should reset capturing groups between two match attempts. Patch by Ma Lin.

bpo-35615 [https://bugs.python.org/issue?@action=redirect&bpo=35615]: weakref: Fix a RuntimeError when copying a WeakKeyDictionary or a WeakValueDictionary, due to some keys or values disappearing while iterating.

bpo-35606 [https://bugs.python.org/issue?@action=redirect&bpo=35606]: Implement math.prod() as analogous function to sum() that returns the product of a ‘start’ value (default: 1) times an iterable of numbers. Patch by Pablo Galindo.

bpo-32417 [https://bugs.python.org/issue?@action=redirect&bpo=32417]: Performing arithmetic between datetime.datetime subclasses and datetime.timedelta now returns an object of the same type as the datetime.datetime subclass. As a result, datetime.datetime.astimezone() and alternate constructors like datetime.datetime.now() and datetime.fromtimestamp() called with a tz argument now also retain their subclass.

bpo-35153 [https://bugs.python.org/issue?@action=redirect&bpo=35153]: Add headers optional keyword-only parameter to xmlrpc.client.ServerProxy, xmlrpc.client.Transport and xmlrpc.client.SafeTransport. Patch by Cédric Krier.

bpo-34572 [https://bugs.python.org/issue?@action=redirect&bpo=34572]: Fix C implementation of pickle.loads to use importlib’s locking mechanisms, and thereby avoid using partially loaded modules. Patch by Tim Burgess.

Documentation

bpo-36083 [https://bugs.python.org/issue?@action=redirect&bpo=36083]: Fix formatting of –check-hash-based-pycs options in the manpage Synopsis.

bpo-36007 [https://bugs.python.org/issue?@action=redirect&bpo=36007]: Bump minimum sphinx version to 1.8. Patch by Anthony Sottile.

bpo-22062 [https://bugs.python.org/issue?@action=redirect&bpo=22062]: Update documentation and docstrings for pathlib. Original patch by Mike Short.

Tests

bpo-27313 [https://bugs.python.org/issue?@action=redirect&bpo=27313]: Avoid test_ttk_guionly ComboboxTest failure with macOS Cocoa Tk.

bpo-36019 [https://bugs.python.org/issue?@action=redirect&bpo=36019]: Add test.support.TEST_HTTP_URL and replace references of http://www.example.com by this new constant. Contributed by Stéphane Wirtel.

bpo-36037 [https://bugs.python.org/issue?@action=redirect&bpo=36037]: Fix test_ssl for strict OpenSSL configuration like RHEL8 strict crypto policy. Use older TLS version for minimum TLS version of the server SSL context if needed, to test TLS version older than default minimum TLS version.

bpo-35798 [https://bugs.python.org/issue?@action=redirect&bpo=35798]: Added test.support.check_syntax_warning().

bpo-35505 [https://bugs.python.org/issue?@action=redirect&bpo=35505]: Make test_imap4_host_default_value independent on whether the local IMAP server is running.

bpo-35917 [https://bugs.python.org/issue?@action=redirect&bpo=35917]: multiprocessing: provide unit tests for SyncManager and SharedMemoryManager classes + all the shareable types which are supposed to be supported by them. (patch by Giampaolo Rodola)

bpo-35704 [https://bugs.python.org/issue?@action=redirect&bpo=35704]: Skip test_shutil.test_unpack_archive_xztar to prevent a MemoryError on 32-bit AIX when MAXDATA setting is less than 0x20000000.

Patch by Michael Felt (aixtools)

bpo-34720 [https://bugs.python.org/issue?@action=redirect&bpo=34720]: Assert m_state != NULL to mimic GC traversal functions that do not correctly handle module creation when the module state has not been created.

Windows

bpo-35976 [https://bugs.python.org/issue?@action=redirect&bpo=35976]: Added ARM build support to Windows build files in PCBuild.

bpo-35692 [https://bugs.python.org/issue?@action=redirect&bpo=35692]: pathlib no longer raises when checking file and directory existence on drives that are not ready

bpo-35872 [https://bugs.python.org/issue?@action=redirect&bpo=35872]: Uses the base Python executable when invoking venv in a virtual environment

bpo-35873 [https://bugs.python.org/issue?@action=redirect&bpo=35873]: Prevents venv paths being inherited by child processes

bpo-35299 [https://bugs.python.org/issue?@action=redirect&bpo=35299]: Fix sysconfig detection of the source directory and distutils handling of pyconfig.h during PGO profiling

IDLE

bpo-24310 [https://bugs.python.org/issue?@action=redirect&bpo=24310]: IDLE – Document settings dialog font tab sample.

bpo-35833 [https://bugs.python.org/issue?@action=redirect&bpo=35833]: Revise IDLE doc for control codes sent to Shell. Add a code example block.

bpo-35689 [https://bugs.python.org/issue?@action=redirect&bpo=35689]: Add docstrings and unittests for colorizer.py.

Python 3.8.0 alpha 1

Release date: 2019-02-03

Security

bpo-35746 [https://bugs.python.org/issue?@action=redirect&bpo=35746]: CVE 2019-5010 [https://www.cve.org/CVERecord?id=CVE-2019-5010]: Fix a NULL pointer deref in ssl module. The cert parser did not handle CRL distribution points with empty DP or URI correctly. A malicious or buggy certificate can result into segfault. Vulnerability (TALOS-2018-0758) reported by Colin Read and Nicolas Edet of Cisco.

bpo-34812 [https://bugs.python.org/issue?@action=redirect&bpo=34812]: The -I command line option (run Python in isolated mode) is now also copied by the multiprocessing and distutils modules when spawning child processes. Previously, only -E and -s options (enabled by -I) were copied.

bpo-34791 [https://bugs.python.org/issue?@action=redirect&bpo=34791]: The xml.sax and xml.dom.domreg no longer use environment variables to override parser implementations when sys.flags.ignore_environment is set by -E or -I arguments.

bpo-17239 [https://bugs.python.org/issue?@action=redirect&bpo=17239]: The xml.sax and xml.dom.minidom parsers no longer processes external entities by default. External DTD and ENTITY declarations no longer load files or create network connections.

bpo-34623 [https://bugs.python.org/issue?@action=redirect&bpo=34623]: CVE 2018-14647 [https://www.cve.org/CVERecord?id=CVE-2018-14647]: The C accelerated _elementtree module now initializes hash randomization salt from _Py_HashSecret instead of libexpat’s default CSPRNG.

bpo-34405 [https://bugs.python.org/issue?@action=redirect&bpo=34405]: Updated to OpenSSL 1.1.0i for Windows builds.

bpo-33871 [https://bugs.python.org/issue?@action=redirect&bpo=33871]: Fixed sending the part of the file in os.sendfile() on macOS. Using the trailers argument could cause sending more bytes from the input file than was specified.

bpo-32533 [https://bugs.python.org/issue?@action=redirect&bpo=32533]: Fixed thread-safety of error handling in _ssl.

bpo-33136 [https://bugs.python.org/issue?@action=redirect&bpo=33136]: Harden ssl module against LibreSSL CVE 2018-8970 [https://www.cve.org/CVERecord?id=CVE-2018-8970]. X509_VERIFY_PARAM_set1_host() is called with an explicit namelen. A new test ensures that NULL bytes are not allowed.

bpo-33001 [https://bugs.python.org/issue?@action=redirect&bpo=33001]: Minimal fix to prevent buffer overrun in os.symlink on Windows

bpo-32981 [https://bugs.python.org/issue?@action=redirect&bpo=32981]: Regexes in difflib and poplib were vulnerable to catastrophic backtracking. These regexes formed potential DOS vectors (REDOS). They have been refactored. This resolves CVE 2018-1060 [https://www.cve.org/CVERecord?id=CVE-2018-1060] and CVE 2018-1061 [https://www.cve.org/CVERecord?id=CVE-2018-1061]. Patch by Jamie Davis.

bpo-28414 [https://bugs.python.org/issue?@action=redirect&bpo=28414]: The ssl module now allows users to perform their own IDN en/decoding when using SNI.

Core and Builtins

bpo-35877 [https://bugs.python.org/issue?@action=redirect&bpo=35877]: Make parenthesis optional for named expressions in while statement. Patch by Karthikeyan Singaravelan.

bpo-35814 [https://bugs.python.org/issue?@action=redirect&bpo=35814]: Allow same right hand side expressions in annotated assignments as in normal ones. In particular, x: Tuple[int, int] = 1, 2 (without parentheses on the right) is now allowed.

bpo-35766 [https://bugs.python.org/issue?@action=redirect&bpo=35766]: Add the option to parse PEP 484 type comments in the ast module. (Off by default.) This is merging the key functionality of the third party fork thereof, [typed_ast](https://github.com/python/typed_ast).

bpo-35713 [https://bugs.python.org/issue?@action=redirect&bpo=35713]: Reorganize Python initialization to get working exceptions and sys.stderr earlier.

bpo-33416 [https://bugs.python.org/issue?@action=redirect&bpo=33416]: Add end line and end column position information to the Python AST nodes. This is a C-level backwards incompatible change.

bpo-35720 [https://bugs.python.org/issue?@action=redirect&bpo=35720]: Fixed a minor memory leak in pymain_parse_cmdline_impl function in Modules/main.c

bpo-35634 [https://bugs.python.org/issue?@action=redirect&bpo=35634]: func(**kwargs) will now raise an error when kwargs is a mapping containing multiple entries with the same key. An error was already raised when other keyword arguments are passed before **kwargs since Python 3.6.

bpo-35623 [https://bugs.python.org/issue?@action=redirect&bpo=35623]: Fix a crash when sorting very long lists. Patch by Stephan Hohe.

bpo-35214 [https://bugs.python.org/issue?@action=redirect&bpo=35214]: clang Memory Sanitizer build instrumentation was added to work around false positives from posix, socket, time, test_io, and test_faulthandler.

bpo-35560 [https://bugs.python.org/issue?@action=redirect&bpo=35560]: Fix an assertion error in format() in debug build for floating-point formatting with “n” format, zero padding and small width. Release build is not impacted. Patch by Karthikeyan Singaravelan.

bpo-35552 [https://bugs.python.org/issue?@action=redirect&bpo=35552]: Format characters %s and %V in PyUnicode_FromFormat() and %s in PyBytes_FromFormat() no longer read memory past the limit if precision is specified.

bpo-35504 [https://bugs.python.org/issue?@action=redirect&bpo=35504]: Fix segfaults and SystemErrors when deleting certain attributes. Patch by Zackery Spytz.

bpo-35504 [https://bugs.python.org/issue?@action=redirect&bpo=35504]: Fixed a SystemError when delete the characters_written attribute of an OSError.

bpo-35494 [https://bugs.python.org/issue?@action=redirect&bpo=35494]: Improved syntax error messages for unbalanced parentheses in f-string.

bpo-35444 [https://bugs.python.org/issue?@action=redirect&bpo=35444]: Fixed error handling in pickling methods when fail to look up builtin “getattr”. Sped up pickling iterators.

bpo-35436 [https://bugs.python.org/issue?@action=redirect&bpo=35436]: Fix various issues with memory allocation error handling. Patch by Zackery Spytz.

bpo-35423 [https://bugs.python.org/issue?@action=redirect&bpo=35423]: Separate the signal handling trigger in the eval loop from the “pending calls” machinery. There is no semantic change and the difference in performance is insignificant.

bpo-35357 [https://bugs.python.org/issue?@action=redirect&bpo=35357]: Internal attributes’ names of unittest.mock._Call and unittest.mock.MagicProxy (name, parent & from_kall) are now prefixed with _mock_ in order to prevent clashes with widely used object attributes. Fixed minor typo in test function name.

bpo-35372 [https://bugs.python.org/issue?@action=redirect&bpo=35372]: Fixed the code page decoder for input longer than 2 GiB containing undecodable bytes.

bpo-35336 [https://bugs.python.org/issue?@action=redirect&bpo=35336]: Fix PYTHONCOERCECLOCALE=1 environment variable: only coerce the C locale if the LC_CTYPE locale is “C”.

bpo-31241 [https://bugs.python.org/issue?@action=redirect&bpo=31241]: The lineno and col_offset attributes of AST nodes for list comprehensions, generator expressions and tuples are now point to the opening parenthesis or square brace. For tuples without parenthesis they point to the position of the first item.

bpo-33954 [https://bugs.python.org/issue?@action=redirect&bpo=33954]: For str.format(), float.__format__() and complex.__format__() methods for non-ASCII decimal point when using the “n” formatter.

bpo-35269 [https://bugs.python.org/issue?@action=redirect&bpo=35269]: Fix a possible segfault involving a newly created coroutine. Patch by Zackery Spytz.

bpo-35224 [https://bugs.python.org/issue?@action=redirect&bpo=35224]: Implement PEP 572 [https://peps.python.org/pep-0572/] (assignment expressions). Patch by Emily Morehouse.

bpo-32492 [https://bugs.python.org/issue?@action=redirect&bpo=32492]: Speed up namedtuple() attribute access by 1.6x using a C fast-path for the name descriptors. Patch by Pablo Galindo.

bpo-35214 [https://bugs.python.org/issue?@action=redirect&bpo=35214]: Fixed an out of bounds memory access when parsing a truncated unicode escape sequence at the end of a string such as '\N'. It would read one byte beyond the end of the memory allocation.

bpo-35214 [https://bugs.python.org/issue?@action=redirect&bpo=35214]: The interpreter and extension modules have had annotations added so that they work properly under clang’s Memory Sanitizer. A new configure flag –with-memory-sanitizer has been added to make test builds of this nature easier to perform.

bpo-35193 [https://bugs.python.org/issue?@action=redirect&bpo=35193]: Fix an off by one error in the bytecode peephole optimizer where it could read bytes beyond the end of bounds of an array when removing unreachable code. This bug was present in every release of Python 3.6 and 3.7 until now.

bpo-35169 [https://bugs.python.org/issue?@action=redirect&bpo=35169]: Improved error messages for forbidden assignments.

bpo-34022 [https://bugs.python.org/issue?@action=redirect&bpo=34022]: Fix handling of hash-based bytecode files in zipimport. Patch by Elvis Pranskevichus.

bpo-28401 [https://bugs.python.org/issue?@action=redirect&bpo=28401]: Debug builds will no longer to attempt to import extension modules built for the ABI as they were never compatible to begin with. Patch by Stefano Rivera.

bpo-29341 [https://bugs.python.org/issue?@action=redirect&bpo=29341]: Clarify in the docstrings of os methods that path-like objects are also accepted as input parameters.

bpo-35050 [https://bugs.python.org/issue?@action=redirect&bpo=35050]: socket: Fix off-by-one bug in length check for AF_ALG name and type.

bpo-29743 [https://bugs.python.org/issue?@action=redirect&bpo=29743]: Raise ValueError instead of OverflowError in case of a negative _length_ in a ctypes.Array subclass. Also raise TypeError instead of AttributeError for non-integer _length_. Original patch by Oren Milman.

bpo-16806 [https://bugs.python.org/issue?@action=redirect&bpo=16806]: Fix lineno and col_offset for multi-line string tokens.

bpo-35029 [https://bugs.python.org/issue?@action=redirect&bpo=35029]: SyntaxWarning raised as an exception at code generation time will be now replaced with a SyntaxError for better error reporting.

bpo-34983 [https://bugs.python.org/issue?@action=redirect&bpo=34983]: Expose symtable.Symbol.is_nonlocal() in the symtable module. Patch by Pablo Galindo.

bpo-34974 [https://bugs.python.org/issue?@action=redirect&bpo=34974]: bytes and bytearray constructors no longer convert unexpected exceptions (e.g. MemoryError and KeyboardInterrupt) to TypeError.

bpo-34939 [https://bugs.python.org/issue?@action=redirect&bpo=34939]: Allow annotated names in module namespace that are declared global before the annotation happens. Patch by Pablo Galindo.

bpo-34973 [https://bugs.python.org/issue?@action=redirect&bpo=34973]: Fixed crash in bytes() when the list argument is mutated while it is iterated.

bpo-34876 [https://bugs.python.org/issue?@action=redirect&bpo=34876]: The lineno and col_offset attributes of the AST for decorated function and class refer now to the position of the corresponding def, async def and class instead of the position of the first decorator. This leads to more correct line reporting in tracing. This is the only case when the position of child AST nodes can precede the position of the parent AST node.

bpo-34879 [https://bugs.python.org/issue?@action=redirect&bpo=34879]: Fix a possible null pointer dereference in bytesobject.c. Patch by Zackery Spytz.

bpo-34784 [https://bugs.python.org/issue?@action=redirect&bpo=34784]: Fix the implementation of PyStructSequence_NewType in order to create heap allocated StructSequences.

bpo-32912 [https://bugs.python.org/issue?@action=redirect&bpo=32912]: A SyntaxWarning is now emitted instead of a DeprecationWarning for invalid escape sequences in string and bytes literals.

bpo-34854 [https://bugs.python.org/issue?@action=redirect&bpo=34854]: Fixed a crash in compiling string annotations containing a lambda with a keyword-only argument that doesn’t have a default value.

bpo-34850 [https://bugs.python.org/issue?@action=redirect&bpo=34850]: The compiler now produces a SyntaxWarning when identity checks (is and is not) are used with certain types of literals (e.g. strings, ints). These can often work by accident in CPython, but are not guaranteed by the language spec. The warning advises users to use equality tests (== and !=) instead.

bpo-34824 [https://bugs.python.org/issue?@action=redirect&bpo=34824]: Fix a possible null pointer dereference in Modules/_ssl.c. Patch by Zackery Spytz.

bpo-30156 [https://bugs.python.org/issue?@action=redirect&bpo=30156]: The C function property_descr_get() uses a “cached” tuple to optimize function calls. But this tuple can be discovered in debug mode with sys.getobjects(). Remove the optimization, it’s not really worth it and it causes 3 different crashes last years.

bpo-34762 [https://bugs.python.org/issue?@action=redirect&bpo=34762]: Fix contextvars C API to use PyObject* pointer types.

bpo-34751 [https://bugs.python.org/issue?@action=redirect&bpo=34751]: The hash function for tuples is now based on xxHash which gives better collision results on (formerly) pathological cases. Additionally, on 64-bit systems it improves tuple hashes in general. Patch by Jeroen Demeyer with substantial contributions by Tim Peters.

bpo-34735 [https://bugs.python.org/issue?@action=redirect&bpo=34735]: Fix a memory leak in Modules/timemodule.c. Patch by Zackery Spytz.

bpo-34683 [https://bugs.python.org/issue?@action=redirect&bpo=34683]: Fixed a bug where some SyntaxError error pointed to locations that were off-by-one.

bpo-34651 [https://bugs.python.org/issue?@action=redirect&bpo=34651]: Only allow the main interpreter to fork. The avoids the possibility of affecting the main interpreter, which is critical to operation of the runtime.

bpo-34653 [https://bugs.python.org/issue?@action=redirect&bpo=34653]: Remove unused function PyParser_SimpleParseStringFilename.

bpo-32236 [https://bugs.python.org/issue?@action=redirect&bpo=32236]: Warn that line buffering is not supported if open() is called with binary mode and buffering=1.

bpo-34641 [https://bugs.python.org/issue?@action=redirect&bpo=34641]: Further restrict the syntax of the left-hand side of keyword arguments in function calls. In particular, f((keyword)=arg) is now disallowed.

bpo-34637 [https://bugs.python.org/issue?@action=redirect&bpo=34637]: Make the start argument to sum() visible as a keyword argument.

bpo-1621 [https://bugs.python.org/issue?@action=redirect&bpo=1621]: Do not assume signed integer overflow behavior (C undefined behavior) when performing set hash table resizing.

bpo-34588 [https://bugs.python.org/issue?@action=redirect&bpo=34588]: Fix an off-by-one in the recursive call pruning feature of traceback formatting.

bpo-34485 [https://bugs.python.org/issue?@action=redirect&bpo=34485]: On Windows, the LC_CTYPE is now set to the user preferred locale at startup. Previously, the LC_CTYPE locale was “C” at startup, but changed when calling setlocale(LC_CTYPE, “”) or setlocale(LC_ALL, “”).

bpo-34485 [https://bugs.python.org/issue?@action=redirect&bpo=34485]: Standard streams like sys.stdout now use the “surrogateescape” error handler, instead of “strict”, on the POSIX locale (when the C locale is not coerced and the UTF-8 Mode is disabled).

bpo-34485 [https://bugs.python.org/issue?@action=redirect&bpo=34485]: Fix the error handler of standard streams like sys.stdout: PYTHONIOENCODING=”:” is now ignored instead of setting the error handler to “strict”.

bpo-34485 [https://bugs.python.org/issue?@action=redirect&bpo=34485]: Python now gets the locale encoding with C code to initialize the encoding of standard streams like sys.stdout. Moreover, the encoding is now initialized to the Python codec name to get a normalized encoding name and to ensure that the codec is loaded. The change avoids importing _bootlocale and _locale modules at startup by default.

bpo-34527 [https://bugs.python.org/issue?@action=redirect&bpo=34527]: On FreeBSD, Py_DecodeLocale() and Py_EncodeLocale() now also forces the ASCII encoding if the LC_CTYPE locale is “POSIX”, not only if the LC_CTYPE locale is “C”.

bpo-34527 [https://bugs.python.org/issue?@action=redirect&bpo=34527]: The UTF-8 Mode is now also enabled by the “POSIX” locale, not only by the “C” locale.

bpo-34403 [https://bugs.python.org/issue?@action=redirect&bpo=34403]: On HP-UX with C or POSIX locale, sys.getfilesystemencoding() now returns “ascii” instead of “roman8” (when the UTF-8 Mode is disabled and the C locale is not coerced).

bpo-34523 [https://bugs.python.org/issue?@action=redirect&bpo=34523]: The Python filesystem encoding is now read earlier during the Python initialization.

bpo-12458 [https://bugs.python.org/issue?@action=redirect&bpo=12458]: Tracebacks show now correct line number for subexpressions in multiline expressions. Tracebacks show now the line number of the first line for multiline expressions instead of the line number of the last subexpression.

bpo-34408 [https://bugs.python.org/issue?@action=redirect&bpo=34408]: Prevent a null pointer dereference and resource leakage in PyInterpreterState_New().

bpo-34400 [https://bugs.python.org/issue?@action=redirect&bpo=34400]: Fix undefined behavior in parsetok.c. Patch by Zackery Spytz.

bpo-33073 [https://bugs.python.org/issue?@action=redirect&bpo=33073]: Added as_integer_ratio to ints to make them more interoperable with floats.

bpo-34377 [https://bugs.python.org/issue?@action=redirect&bpo=34377]: Update valgrind suppression list to use _PyObject_Free/_PyObject_Realloc instead of PyObject_Free/PyObject_Realloc.

bpo-34353 [https://bugs.python.org/issue?@action=redirect&bpo=34353]: Added the “socket” option in the stat.filemode() Python implementation to match the C implementation.

bpo-34320 [https://bugs.python.org/issue?@action=redirect&bpo=34320]: Fix dict(od) didn’t copy iteration order of OrderedDict.

bpo-34113 [https://bugs.python.org/issue?@action=redirect&bpo=34113]: Fixed crash on debug builds when opcode stack was adjusted with negative numbers. Patch by Constantin Petrisor.

bpo-34100 [https://bugs.python.org/issue?@action=redirect&bpo=34100]: Compiler now merges constants in tuples and frozensets recursively. Code attributes like co_names are merged too.

bpo-34151 [https://bugs.python.org/issue?@action=redirect&bpo=34151]: Performance of list concatenation, repetition and slicing operations is slightly improved. Patch by Sergey Fedoseev.

bpo-34170 [https://bugs.python.org/issue?@action=redirect&bpo=34170]: -X dev: it is now possible to override the memory allocator using PYTHONMALLOC even if the developer mode is enabled.

bpo-33237 [https://bugs.python.org/issue?@action=redirect&bpo=33237]: Improved AttributeError message for partially initialized module.

bpo-34149 [https://bugs.python.org/issue?@action=redirect&bpo=34149]: Fix min and max functions to get default behavior when key is None.

bpo-34125 [https://bugs.python.org/issue?@action=redirect&bpo=34125]: Profiling of unbound built-in methods now works when **kwargs is given.

bpo-34141 [https://bugs.python.org/issue?@action=redirect&bpo=34141]: Optimized pickling atomic types (None, bool, int, float, bytes, str).

bpo-34126 [https://bugs.python.org/issue?@action=redirect&bpo=34126]: Fix crashes when profiling certain invalid calls of unbound methods. Patch by Jeroen Demeyer.

bpo-24618 [https://bugs.python.org/issue?@action=redirect&bpo=24618]: Fixed reading invalid memory when create the code object with too small varnames tuple or too large argument counts.

bpo-34068 [https://bugs.python.org/issue?@action=redirect&bpo=34068]: In io.IOBase.close(), ensure that the closed attribute is not set with a live exception. Patch by Zackery Spytz and Serhiy Storchaka.

bpo-34087 [https://bugs.python.org/issue?@action=redirect&bpo=34087]: Fix buffer overflow while converting unicode to numeric values.

bpo-34080 [https://bugs.python.org/issue?@action=redirect&bpo=34080]: Fixed a memory leak in the compiler when it raised some uncommon errors during tokenizing.

bpo-34066 [https://bugs.python.org/issue?@action=redirect&bpo=34066]: Disabled interruption by Ctrl-C between calling open() and entering a with block in with open().

bpo-34042 [https://bugs.python.org/issue?@action=redirect&bpo=34042]: Fix dict.copy() to maintain correct total refcount (as reported by sys.gettotalrefcount()).

bpo-33418 [https://bugs.python.org/issue?@action=redirect&bpo=33418]: Fix potential memory leak in function object when it creates reference cycle.

bpo-33985 [https://bugs.python.org/issue?@action=redirect&bpo=33985]: Implement contextvars.ContextVar.name attribute.

bpo-33956 [https://bugs.python.org/issue?@action=redirect&bpo=33956]: Update vendored Expat library copy to version 2.2.5.

bpo-24596 [https://bugs.python.org/issue?@action=redirect&bpo=24596]: Decref the module object in PyRun_SimpleFileExFlags() before calling PyErr_Print(). Patch by Zackery Spytz.

bpo-33451 [https://bugs.python.org/issue?@action=redirect&bpo=33451]: Close directly executed pyc files before calling PyEval_EvalCode().

bpo-1617161 [https://bugs.python.org/issue?@action=redirect&bpo=1617161]: The hash of BuiltinMethodType instances (methods of built-in classes) now depends on the hash of the identity of __self__ instead of its value. The hash and equality of ModuleType and MethodWrapperType instances (methods of user-defined classes and some methods of built-in classes like str.__add__) now depend on the hash and equality of the identity of __self__ instead of its value. MethodWrapperType instances no longer support ordering.

bpo-33824 [https://bugs.python.org/issue?@action=redirect&bpo=33824]: Fix “LC_ALL=C python3.7 -V”: reset properly the command line parser when the encoding changes after reading the Python configuration.

bpo-33803 [https://bugs.python.org/issue?@action=redirect&bpo=33803]: Fix a crash in hamt.c caused by enabling GC tracking for an object that hadn’t all of its fields set to NULL.

bpo-33738 [https://bugs.python.org/issue?@action=redirect&bpo=33738]: Seven macro incompatibilities with the Limited API were fixed, and the macros PyIter_Check(), PyIndex_Check() and PyExceptionClass_Name() were added as functions. A script for automatic macro checks was added.

bpo-33786 [https://bugs.python.org/issue?@action=redirect&bpo=33786]: Fix asynchronous generators to handle GeneratorExit in athrow() correctly

bpo-30167 [https://bugs.python.org/issue?@action=redirect&bpo=30167]: PyRun_SimpleFileExFlags removes __cached__ from module in addition to __file__.

bpo-33706 [https://bugs.python.org/issue?@action=redirect&bpo=33706]: Fix a crash in Python initialization when parsing the command line options. Thanks Christoph Gohlke for the bug report and the fix!

bpo-33597 [https://bugs.python.org/issue?@action=redirect&bpo=33597]: Reduce PyGC_Head size from 3 words to 2 words.

bpo-30654 [https://bugs.python.org/issue?@action=redirect&bpo=30654]: Fixed reset of the SIGINT handler to SIG_DFL on interpreter shutdown even when there was a custom handler set previously. Patch by Philipp Kerling.

bpo-33622 [https://bugs.python.org/issue?@action=redirect&bpo=33622]: Fixed a leak when the garbage collector fails to add an object with the __del__ method or referenced by it into the gc.garbage list. PyGC_Collect() can now be called when an exception is set and preserves it.

bpo-33462 [https://bugs.python.org/issue?@action=redirect&bpo=33462]: Make dict and dict views reversible. Patch by Rémi Lapeyre.

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: A RuntimeError is now raised when the custom metaclass doesn’t provide the __classcell__ entry in the namespace passed to type.__new__. A DeprecationWarning was emitted in Python 3.6–3.7.

bpo-33499 [https://bugs.python.org/issue?@action=redirect&bpo=33499]: Add PYTHONPYCACHEPREFIX environment variable and -X pycache_prefix command-line option to set an alternate root directory for writing module bytecode cache files.

bpo-25711 [https://bugs.python.org/issue?@action=redirect&bpo=25711]: The zipimport module has been rewritten in pure Python.

bpo-33509 [https://bugs.python.org/issue?@action=redirect&bpo=33509]: Fix module_globals parameter of warnings.warn_explicit(): don’t crash if module_globals is not a dict.

bpo-31849 [https://bugs.python.org/issue?@action=redirect&bpo=31849]: Fix signed/unsigned comparison warning in pyhash.c.

bpo-33475 [https://bugs.python.org/issue?@action=redirect&bpo=33475]: Fixed miscellaneous bugs in converting annotations to strings and optimized parentheses in the string representation.

bpo-20104 [https://bugs.python.org/issue?@action=redirect&bpo=20104]: Added support for the setpgroup, resetids, setsigmask, setsigdef and scheduler parameters of posix_spawn. Patch by Pablo Galindo.

bpo-33391 [https://bugs.python.org/issue?@action=redirect&bpo=33391]: Fix a leak in set_symmetric_difference().

bpo-33363 [https://bugs.python.org/issue?@action=redirect&bpo=33363]: Raise a SyntaxError for async with and async for statements outside of async functions.

bpo-28055 [https://bugs.python.org/issue?@action=redirect&bpo=28055]: Fix unaligned accesses in siphash24(). Patch by Rolf Eike Beer.

bpo-33128 [https://bugs.python.org/issue?@action=redirect&bpo=33128]: Fix a bug that causes PathFinder to appear twice on sys.meta_path. Patch by Pablo Galindo Salgado.

bpo-33331 [https://bugs.python.org/issue?@action=redirect&bpo=33331]: Modules imported last are now cleared first at interpreter shutdown.

bpo-33312 [https://bugs.python.org/issue?@action=redirect&bpo=33312]: Fixed clang ubsan (undefined behavior sanitizer) warnings in dictobject.c by adjusting how the internal struct _dictkeysobject shared keys structure is declared.

bpo-33305 [https://bugs.python.org/issue?@action=redirect&bpo=33305]: Improved syntax error messages for invalid numerical literals.

bpo-33306 [https://bugs.python.org/issue?@action=redirect&bpo=33306]: Improved syntax error messages for unbalanced parentheses.

bpo-33234 [https://bugs.python.org/issue?@action=redirect&bpo=33234]: The list constructor will pre-size and not over-allocate when the input length is known.

bpo-33270 [https://bugs.python.org/issue?@action=redirect&bpo=33270]: Intern the names for all anonymous code objects. Patch by Zackery Spytz.

bpo-30455 [https://bugs.python.org/issue?@action=redirect&bpo=30455]: The C and Python code and the documentation related to tokens are now generated from a single source file Grammar/Tokens.

bpo-33176 [https://bugs.python.org/issue?@action=redirect&bpo=33176]: Add a toreadonly() method to memoryviews.

bpo-33231 [https://bugs.python.org/issue?@action=redirect&bpo=33231]: Fix potential memory leak in normalizestring().

bpo-33205 [https://bugs.python.org/issue?@action=redirect&bpo=33205]: Change dict growth function from round_up_to_power_2(used*2+hashtable_size/2) to round_up_to_power_2(used*3). Previously, dict is shrunk only when used == 0. Now dict has more chance to be shrunk.

bpo-29922 [https://bugs.python.org/issue?@action=redirect&bpo=29922]: Improved error messages in ‘async with’ when __aenter__() or __aexit__() return non-awaitable object.

bpo-33199 [https://bugs.python.org/issue?@action=redirect&bpo=33199]: Fix ma_version_tag in dict implementation is uninitialized when copying from key-sharing dict.

bpo-33053 [https://bugs.python.org/issue?@action=redirect&bpo=33053]: When using the -m switch, sys.path[0] is now explicitly expanded as the starting working directory, rather than being left as the empty path (which allows imports from the current working directory at the time of the import)

bpo-33138 [https://bugs.python.org/issue?@action=redirect&bpo=33138]: Changed standard error message for non-pickleable and non-copyable types. It now says “cannot pickle” instead of “can’t pickle” or “cannot serialize”.

bpo-33018 [https://bugs.python.org/issue?@action=redirect&bpo=33018]: Improve consistency of errors raised by issubclass() when called with a non-class and an abstract base class as the first and second arguments, respectively. Patch by Josh Bronson.

bpo-33083 [https://bugs.python.org/issue?@action=redirect&bpo=33083]: math.factorial no longer accepts arguments that are not int-like. Patch by Pablo Galindo.

bpo-33041 [https://bugs.python.org/issue?@action=redirect&bpo=33041]: Added new opcode END_ASYNC_FOR and fixes the following issues:

Setting global StopAsyncIteration no longer breaks async for loops.

Jumping into an async for loop is now disabled.

Jumping out of an async for loop no longer corrupts the stack.

bpo-25750 [https://bugs.python.org/issue?@action=redirect&bpo=25750]: Fix rare Python crash due to bad refcounting in type_getattro() if a descriptor deletes itself from the class. Patch by Jeroen Demeyer.

bpo-33041 [https://bugs.python.org/issue?@action=redirect&bpo=33041]: Fixed bytecode generation for “async for” with a complex target. A StopAsyncIteration raised on assigning or unpacking will be now propagated instead of stopping the iteration.

bpo-33026 [https://bugs.python.org/issue?@action=redirect&bpo=33026]: Fixed jumping out of “with” block by setting f_lineno.

bpo-33005 [https://bugs.python.org/issue?@action=redirect&bpo=33005]: Fix a crash on fork when using a custom memory allocator (ex: using PYTHONMALLOC env var). _PyGILState_Reinit() and _PyInterpreterState_Enable() now use the default RAW memory allocator to allocate a new interpreters mutex on fork.

bpo-32911 [https://bugs.python.org/issue?@action=redirect&bpo=32911]: Due to unexpected compatibility issues discovered during downstream beta testing, reverted bpo-29463 [https://bugs.python.org/issue?@action=redirect&bpo=29463]. docstring field is removed from Module, ClassDef, FunctionDef, and AsyncFunctionDef ast nodes which was added in 3.7a1. Docstring expression is restored as a first statement in their body. Based on patch by Inada Naoki.

bpo-17288 [https://bugs.python.org/issue?@action=redirect&bpo=17288]: Prevent jumps from ‘return’ and ‘exception’ trace events.

bpo-32946 [https://bugs.python.org/issue?@action=redirect&bpo=32946]: Importing names from already imported module with “from … import …” is now 30% faster if the module is not a package.

bpo-32932 [https://bugs.python.org/issue?@action=redirect&bpo=32932]: Make error message more revealing when there are non-str objects in __all__.

bpo-32925 [https://bugs.python.org/issue?@action=redirect&bpo=32925]: Optimized iterating and containing test for literal lists consisting of non-constants: x in [a, b] and for x in [a, b]. The case of all constant elements already was optimized.

bpo-32889 [https://bugs.python.org/issue?@action=redirect&bpo=32889]: Update Valgrind suppression list to account for the rename of Py_ADDRESS_IN_RANG to address_in_range.

bpo-32836 [https://bugs.python.org/issue?@action=redirect&bpo=32836]: Don’t use temporary variables in cases of list/dict/set comprehensions

bpo-31356 [https://bugs.python.org/issue?@action=redirect&bpo=31356]: Remove the new API added in bpo-31356 [https://bugs.python.org/issue?@action=redirect&bpo=31356] (gc.ensure_disabled() context manager).

bpo-32305 [https://bugs.python.org/issue?@action=redirect&bpo=32305]: For namespace packages, ensure that both __file__ and __spec__.origin are set to None.

bpo-32303 [https://bugs.python.org/issue?@action=redirect&bpo=32303]: Make sure __spec__.loader matches __loader__ for namespace packages.

bpo-32711 [https://bugs.python.org/issue?@action=redirect&bpo=32711]: Fix the warning messages for Python/ast_unparse.c. Patch by Stéphane Wirtel

bpo-32583 [https://bugs.python.org/issue?@action=redirect&bpo=32583]: Fix possible crashing in builtin Unicode decoders caused by write out-of-bound errors when using customized decode error handlers.

bpo-32489 [https://bugs.python.org/issue?@action=redirect&bpo=32489]: A continue statement is now allowed in the finally clause.

bpo-17611 [https://bugs.python.org/issue?@action=redirect&bpo=17611]: Simplified the interpreter loop by moving the logic of unrolling the stack of blocks into the compiler. The compiler emits now explicit instructions for adjusting the stack of values and calling the cleaning up code for break, continue and return.

Removed opcodes BREAK_LOOP, CONTINUE_LOOP, SETUP_LOOP and SETUP_EXCEPT. Added new opcodes ROT_FOUR, BEGIN_FINALLY and CALL_FINALLY and POP_FINALLY. Changed the behavior of END_FINALLY and WITH_CLEANUP_START.

bpo-32285 [https://bugs.python.org/issue?@action=redirect&bpo=32285]: New function unicodedata.is_normalized, which can check whether a string is in a specific normal form.

bpo-10544 [https://bugs.python.org/issue?@action=redirect&bpo=10544]: Yield expressions are now disallowed in comprehensions and generator expressions except the expression for the outermost iterable.

bpo-32117 [https://bugs.python.org/issue?@action=redirect&bpo=32117]: Iterable unpacking is now allowed without parentheses in yield and return statements, e.g. yield 1, 2, 3, *rest. Thanks to David Cuthbert for the change and Jordan Chapman for added tests.

bpo-31902 [https://bugs.python.org/issue?@action=redirect&bpo=31902]: Fix the col_offset attribute for ast nodes ast.AsyncFor, ast.AsyncFunctionDef, and ast.AsyncWith. Previously, col_offset pointed to the keyword after async.

bpo-25862 [https://bugs.python.org/issue?@action=redirect&bpo=25862]: Fix assertion failures in the tell() method of io.TextIOWrapper. Patch by Zackery Spytz.

bpo-21983 [https://bugs.python.org/issue?@action=redirect&bpo=21983]: Fix a crash in ctypes.cast() in case the type argument is a ctypes structured data type. Patch by Eryk Sun and Oren Milman.

bpo-31577 [https://bugs.python.org/issue?@action=redirect&bpo=31577]: Fix a crash in os.utime() in case of a bad ns argument. Patch by Oren Milman.

bpo-29832 [https://bugs.python.org/issue?@action=redirect&bpo=29832]: Remove references to ‘getsockaddrarg’ from various socket error messages. Patch by Oren Milman.

Library

bpo-35845 [https://bugs.python.org/issue?@action=redirect&bpo=35845]: Add ‘order’ parameter to memoryview.tobytes().

bpo-35864 [https://bugs.python.org/issue?@action=redirect&bpo=35864]: The _asdict() method for collections.namedtuple now returns a regular dict instead of an OrderedDict.

bpo-35537 [https://bugs.python.org/issue?@action=redirect&bpo=35537]: An ExitStack is now used internally within subprocess.Popen to clean up pipe file handles. No behavior change in normal operation. But if closing one handle were ever to cause an exception, the others will now be closed instead of leaked. (patch by Giampaolo Rodola)

bpo-35847 [https://bugs.python.org/issue?@action=redirect&bpo=35847]: RISC-V needed the CTYPES_PASS_BY_REF_HACK. Fixes ctypes Structure test_pass_by_value.

bpo-35813 [https://bugs.python.org/issue?@action=redirect&bpo=35813]: Shared memory submodule added to multiprocessing to avoid need for serialization between processes

bpo-35780 [https://bugs.python.org/issue?@action=redirect&bpo=35780]: Fix lru_cache() errors arising in recursive, reentrant, or multi-threaded code. These errors could result in orphan links and in the cache being trapped in a state with fewer than the specified maximum number of links. Fix handling of negative maxsize which should have been treated as zero. Fix errors in toggling the “full” status flag. Fix misordering of links when errors are encountered. Sync-up the C code and pure Python code for the space saving path in functions with a single positional argument. In this common case, the space overhead of an lru cache entry is reduced by almost half. Fix counting of cache misses. In error cases, the miss count was out of sync with the actual number of times the underlying user function was called.

bpo-35537 [https://bugs.python.org/issue?@action=redirect&bpo=35537]: os.posix_spawn() and os.posix_spawnp() now have a setsid parameter.

bpo-23846 [https://bugs.python.org/issue?@action=redirect&bpo=23846]: asyncio.ProactorEventLoop now catches and logs send errors when the self-pipe is full.

bpo-34323 [https://bugs.python.org/issue?@action=redirect&bpo=34323]: asyncio: Enhance IocpProactor.close() log: wait 1 second before the first log, then log every second. Log also the number of seconds since close() was called.

bpo-35674 [https://bugs.python.org/issue?@action=redirect&bpo=35674]: Add a new os.posix_spawnp() function. Patch by Joannah Nanjekye.

bpo-35733 [https://bugs.python.org/issue?@action=redirect&bpo=35733]: ast.Constant(boolean) no longer an instance of ast.Num. Patch by Anthony Sottile.

bpo-35726 [https://bugs.python.org/issue?@action=redirect&bpo=35726]: QueueHandler.prepare() now makes a copy of the record before modifying and enqueueing it, to avoid affecting other handlers in the chain.

bpo-35719 [https://bugs.python.org/issue?@action=redirect&bpo=35719]: Sped up multi-argument math functions atan2(), copysign(), remainder() and hypot() by 1.3–2.5 times.

bpo-35717 [https://bugs.python.org/issue?@action=redirect&bpo=35717]: Fix KeyError exception raised when using enums and compile. Patch contributed by Rémi Lapeyre.

bpo-35699 [https://bugs.python.org/issue?@action=redirect&bpo=35699]: Fixed detection of Visual Studio Build Tools 2017 in distutils

bpo-32710 [https://bugs.python.org/issue?@action=redirect&bpo=32710]: Fix memory leaks in asyncio ProactorEventLoop on overlapped operation failure.

bpo-35702 [https://bugs.python.org/issue?@action=redirect&bpo=35702]: The time.CLOCK_UPTIME_RAW constant is now available for macOS 10.12.

bpo-32710 [https://bugs.python.org/issue?@action=redirect&bpo=32710]: Fix a memory leak in asyncio in the ProactorEventLoop when ReadFile() or WSASend() overlapped operation fail immediately: release the internal buffer.

bpo-35682 [https://bugs.python.org/issue?@action=redirect&bpo=35682]: Fix asyncio.ProactorEventLoop.sendfile(): don’t attempt to set the result of an internal future if it’s already done.

bpo-35283 [https://bugs.python.org/issue?@action=redirect&bpo=35283]: Add a deprecated warning for the threading.Thread.isAlive() method. Patch by Donghee Na.

bpo-35664 [https://bugs.python.org/issue?@action=redirect&bpo=35664]: Improve operator.itemgetter() performance by 33% with optimized argument handling and with adding a fast path for the common case of a single non-negative integer index into a tuple (which is the typical use case in the standard library).

bpo-35643 [https://bugs.python.org/issue?@action=redirect&bpo=35643]: Fixed a SyntaxWarning: invalid escape sequence in Modules/_sha3/cleanup.py. Patch by Mickaël Schoentgen.

bpo-35619 [https://bugs.python.org/issue?@action=redirect&bpo=35619]: Improved support of custom data descriptors in help() and pydoc.

bpo-28503 [https://bugs.python.org/issue?@action=redirect&bpo=28503]: The crypt module now internally uses the crypt_r() library function instead of crypt() when available.

bpo-35614 [https://bugs.python.org/issue?@action=redirect&bpo=35614]: Fixed help() on metaclasses. Patch by Sanyam Khurana.

bpo-35568 [https://bugs.python.org/issue?@action=redirect&bpo=35568]: Expose raise(signum) as raise_signal

bpo-35588 [https://bugs.python.org/issue?@action=redirect&bpo=35588]: The floor division and modulo operations and the divmod() function on fractions.Fraction types are 2–4x faster. Patch by Stefan Behnel.

bpo-35585 [https://bugs.python.org/issue?@action=redirect&bpo=35585]: Speed-up building enums by value, e.g. http.HTTPStatus(200).

bpo-30561 [https://bugs.python.org/issue?@action=redirect&bpo=30561]: random.gammavariate(1.0, beta) now computes the same result as random.expovariate(1.0 / beta). This synchronizes the two algorithms and eliminates some idiosyncrasies in the old implementation. It does however produce a difference stream of random variables than it used to.

bpo-35537 [https://bugs.python.org/issue?@action=redirect&bpo=35537]: The subprocess module can now use the os.posix_spawn() function in some cases for better performance.

bpo-35526 [https://bugs.python.org/issue?@action=redirect&bpo=35526]: Delaying the ‘joke’ of barry_as_FLUFL.mandatory to Python version 4.0

bpo-35523 [https://bugs.python.org/issue?@action=redirect&bpo=35523]: Remove ctypes callback workaround: no longer create a callback at startup. Avoid SELinux alert on import ctypes and import uuid.

bpo-31784 [https://bugs.python.org/issue?@action=redirect&bpo=31784]: uuid.uuid1() now calls time.time_ns() rather than int(time.time() * 1e9).

bpo-35513 [https://bugs.python.org/issue?@action=redirect&bpo=35513]: TextTestRunner of unittest.runner now uses time.perf_counter() rather than time.time() to measure the execution time of a test: time.time() can go backwards, whereas time.perf_counter() is monotonic.

bpo-35502 [https://bugs.python.org/issue?@action=redirect&bpo=35502]: Fixed reference leaks in xml.etree.ElementTree.TreeBuilder in case of unfinished building of the tree (in particular when an error was raised during parsing XML).

bpo-35348 [https://bugs.python.org/issue?@action=redirect&bpo=35348]: Make platform.architecture() parsing of file command output more reliable: add the -b option to the file command to omit the filename, force the usage of the C locale, and search also the “shared object” pattern.

bpo-35491 [https://bugs.python.org/issue?@action=redirect&bpo=35491]: multiprocessing: Add Pool.__repr__() and enhance BaseProcess.__repr__() (add pid and parent pid) to ease debugging. Pool state constant values are now strings instead of integers, for example RUN value becomes 'RUN' instead of 0.

bpo-35477 [https://bugs.python.org/issue?@action=redirect&bpo=35477]: multiprocessing.Pool.__enter__() now fails if the pool is not running: with pool: fails if used more than once.

bpo-31446 [https://bugs.python.org/issue?@action=redirect&bpo=31446]: Copy command line that was passed to CreateProcessW since this function can change the content of the input buffer.

bpo-35471 [https://bugs.python.org/issue?@action=redirect&bpo=35471]: Python 2.4 dropped MacOS 9 support. The macpath module was deprecated in Python 3.7. The module is now removed.

bpo-23057 [https://bugs.python.org/issue?@action=redirect&bpo=23057]: Unblock Proactor event loop when keyboard interrupt is received on Windows

bpo-35052 [https://bugs.python.org/issue?@action=redirect&bpo=35052]: Fix xml.dom.minidom cloneNode() on a document with an entity: pass the correct arguments to the user data handler of an entity.

bpo-20239 [https://bugs.python.org/issue?@action=redirect&bpo=20239]: Allow repeated assignment deletion of unittest.mock.Mock attributes. Patch by Pablo Galindo.

bpo-17185 [https://bugs.python.org/issue?@action=redirect&bpo=17185]: Set __signature__ on mock for inspect to get signature. Patch by Karthikeyan Singaravelan.

bpo-35445 [https://bugs.python.org/issue?@action=redirect&bpo=35445]: Memory errors during creating posix.environ no longer ignored.

bpo-35415 [https://bugs.python.org/issue?@action=redirect&bpo=35415]: Validate fileno= argument to socket.socket().

bpo-35424 [https://bugs.python.org/issue?@action=redirect&bpo=35424]: multiprocessing.Pool destructor now emits ResourceWarning if the pool is still running.

bpo-35330 [https://bugs.python.org/issue?@action=redirect&bpo=35330]: When a Mock instance was used to wrap an object, if side_effect is used in one of the mocks of it methods, don’t call the original implementation and return the result of using the side effect the same way that it is done with return_value.

bpo-35346 [https://bugs.python.org/issue?@action=redirect&bpo=35346]: Drop Mac OS 9 and Rhapsody support from the platform module. Rhapsody last release was in 2000. Mac OS 9 last release was in 2001.

bpo-10496 [https://bugs.python.org/issue?@action=redirect&bpo=10496]: check_environ() of distutils.utils now catches KeyError on calling pwd.getpwuid(): don’t create the HOME environment variable in this case.

bpo-10496 [https://bugs.python.org/issue?@action=redirect&bpo=10496]: posixpath.expanduser() now returns the input path unchanged if the HOME environment variable is not set and the current user has no home directory (if the current user identifier doesn’t exist in the password database). This change fix the site module if the current user doesn’t exist in the password database (if the user has no home directory).

bpo-35389 [https://bugs.python.org/issue?@action=redirect&bpo=35389]: platform.libc_ver() now uses os.confstr('CS_GNU_LIBC_VERSION') if available and the executable parameter is not set.

bpo-35394 [https://bugs.python.org/issue?@action=redirect&bpo=35394]: Add empty slots to asyncio abstract protocols.

bpo-35310 [https://bugs.python.org/issue?@action=redirect&bpo=35310]: Fix a bug in select.select() where, in some cases, the file descriptor sequences were returned unmodified after a signal interruption, even though the file descriptors might not be ready yet. select.select() will now always return empty lists if a timeout has occurred. Patch by Oran Avraham.

bpo-35380 [https://bugs.python.org/issue?@action=redirect&bpo=35380]: Enable TCP_NODELAY on Windows for proactor asyncio event loop.

bpo-35341 [https://bugs.python.org/issue?@action=redirect&bpo=35341]: Add generic version of collections.OrderedDict to the typing module. Patch by Ismo Toijala.

bpo-35371 [https://bugs.python.org/issue?@action=redirect&bpo=35371]: Fixed possible crash in os.utime() on Windows when pass incorrect arguments.

bpo-35346 [https://bugs.python.org/issue?@action=redirect&bpo=35346]: platform.uname() now redirects stderr to os.devnull when running external programs like cmd /c ver.

bpo-35066 [https://bugs.python.org/issue?@action=redirect&bpo=35066]: Previously, calling the strftime() method on a datetime object with a trailing ‘%’ in the format string would result in an exception. However, this only occurred when the datetime C module was being used; the python implementation did not match this behavior. Datetime is now PEP-399 compliant, and will not throw an exception on a trailing ‘%’.

bpo-35345 [https://bugs.python.org/issue?@action=redirect&bpo=35345]: The function platform.popen has been removed, it was deprecated since Python 3.3: use os.popen() instead.

bpo-35344 [https://bugs.python.org/issue?@action=redirect&bpo=35344]: On macOS, platform.platform() now uses platform.mac_ver(), if it returns a non-empty release string, to get the macOS version rather than the darwin version.

bpo-35312 [https://bugs.python.org/issue?@action=redirect&bpo=35312]: Make lib2to3.pgen2.parse.ParseError round-trip pickle-able. Patch by Anthony Sottile.

bpo-35308 [https://bugs.python.org/issue?@action=redirect&bpo=35308]: Fix regression in webbrowser where default browsers may be preferred over browsers in the BROWSER environment variable.

bpo-24746 [https://bugs.python.org/issue?@action=redirect&bpo=24746]: Avoid stripping trailing whitespace in doctest fancy diff. Original patch by R. David Murray & Jairo Trad. Enhanced by Sanyam Khurana.

bpo-28604 [https://bugs.python.org/issue?@action=redirect&bpo=28604]: locale.localeconv() now sets temporarily the LC_CTYPE locale to the LC_MONETARY locale if the two locales are different and monetary strings are non-ASCII. This temporary change affects other threads.

bpo-35277 [https://bugs.python.org/issue?@action=redirect&bpo=35277]: Update ensurepip to install pip 18.1 and setuptools 40.6.2.

bpo-24209 [https://bugs.python.org/issue?@action=redirect&bpo=24209]: Adds IPv6 support when invoking http.server directly.

bpo-35226 [https://bugs.python.org/issue?@action=redirect&bpo=35226]: Recursively check arguments when testing for equality of unittest.mock.call objects and add note that tracking of parameters used to create ancestors of mocks in mock_calls is not possible.

bpo-29564 [https://bugs.python.org/issue?@action=redirect&bpo=29564]: The warnings module now suggests to enable tracemalloc if the source is specified, the tracemalloc module is available, but tracemalloc is not tracing memory allocations.

bpo-35189 [https://bugs.python.org/issue?@action=redirect&bpo=35189]: Modify the following fnctl function to retry if interrupted by a signal (EINTR): flock, lockf, fnctl

bpo-30064 [https://bugs.python.org/issue?@action=redirect&bpo=30064]: Use add_done_callback() in sock_* asyncio API to unsubscribe reader/writer early on calcellation.

bpo-35186 [https://bugs.python.org/issue?@action=redirect&bpo=35186]: Removed the “built with” comment added when setup.py upload is used with either bdist_rpm or bdist_dumb.

bpo-35152 [https://bugs.python.org/issue?@action=redirect&bpo=35152]: Allow sending more than 2 GB at once on a multiprocessing connection on non-Windows systems.

bpo-35062 [https://bugs.python.org/issue?@action=redirect&bpo=35062]: Fix incorrect parsing of io.IncrementalNewlineDecoder’s translate argument.

bpo-35065 [https://bugs.python.org/issue?@action=redirect&bpo=35065]: Remove StreamReaderProtocol._untrack_reader. The call to _untrack_reader is currently performed too soon, causing the protocol to forget about the reader before connection_lost can run and feed the EOF to the reader.

bpo-34160 [https://bugs.python.org/issue?@action=redirect&bpo=34160]: ElementTree and minidom now preserve the attribute order specified by the user.

bpo-35079 [https://bugs.python.org/issue?@action=redirect&bpo=35079]: Improve difflib.SequenceManager.get_matching_blocks doc by adding ‘non-overlapping’ and changing ‘!=’ to ‘<’.

bpo-33710 [https://bugs.python.org/issue?@action=redirect&bpo=33710]: Deprecated l*gettext() functions and methods in the gettext module. They return encoded bytes instead of Unicode strings and are artifacts from Python 2 times. Also deprecated functions and methods related to setting the charset for l*gettext() functions and methods.

bpo-35017 [https://bugs.python.org/issue?@action=redirect&bpo=35017]: socketserver.BaseServer.serve_forever() now exits immediately if it’s shutdown() method is called while it is polling for new events.

bpo-35024 [https://bugs.python.org/issue?@action=redirect&bpo=35024]: importlib no longer logs wrote <bytecode path> redundantly after (created|could not create) <bytecode path> is already logged. Patch by Quentin Agren.

bpo-35047 [https://bugs.python.org/issue?@action=redirect&bpo=35047]: unittest.mock now includes mock calls in exception messages if assert_not_called, assert_called_once, or assert_called_once_with fails. Patch by Petter Strandmark.

bpo-31047 [https://bugs.python.org/issue?@action=redirect&bpo=31047]: Fix ntpath.abspath regression where it didn’t remove a trailing separator on Windows. Patch by Tim Graham.

bpo-35053 [https://bugs.python.org/issue?@action=redirect&bpo=35053]: tracemalloc now tries to update the traceback when an object is reused from a “free list” (optimization for faster object creation, used by the builtin list type for example).

bpo-31553 [https://bugs.python.org/issue?@action=redirect&bpo=31553]: Add the –json-lines option to json.tool. Patch by hongweipeng.

bpo-34794 [https://bugs.python.org/issue?@action=redirect&bpo=34794]: Fixed a leak in Tkinter when pass the Python wrapper around Tcl_Obj back to Tcl/Tk.

bpo-34909 [https://bugs.python.org/issue?@action=redirect&bpo=34909]: Enum: fix grandchildren subclassing when parent mixed with concrete data types.

bpo-35022 [https://bugs.python.org/issue?@action=redirect&bpo=35022]: unittest.mock.MagicMock now supports the __fspath__ method (from os.PathLike).

bpo-35008 [https://bugs.python.org/issue?@action=redirect&bpo=35008]: Fixed references leaks when call the __setstate__() method of xml.etree.ElementTree.Element in the C implementation for already initialized element.

bpo-23420 [https://bugs.python.org/issue?@action=redirect&bpo=23420]: Verify the value for the parameter ‘-s’ of the cProfile CLI. Patch by Robert Kuska

bpo-33947 [https://bugs.python.org/issue?@action=redirect&bpo=33947]: dataclasses now handle recursive reprs without raising RecursionError.

bpo-34890 [https://bugs.python.org/issue?@action=redirect&bpo=34890]: Make inspect.iscoroutinefunction(), inspect.isgeneratorfunction() and inspect.isasyncgenfunction() work with functools.partial(). Patch by Pablo Galindo.

bpo-34521 [https://bugs.python.org/issue?@action=redirect&bpo=34521]: Use socket.CMSG_SPACE() to calculate ancillary data size instead of socket.CMSG_LEN() in multiprocessing.reduction.recvfds() as RFC 3542 [https://datatracker.ietf.org/doc/html/rfc3542.html] requires the use of the former for portable applications.

bpo-31522 [https://bugs.python.org/issue?@action=redirect&bpo=31522]: The mailbox.mbox.get_string function from_ parameter can now successfully be set to a non-default value.

bpo-34970 [https://bugs.python.org/issue?@action=redirect&bpo=34970]: Protect tasks weak set manipulation in asyncio.all_tasks()

bpo-34969 [https://bugs.python.org/issue?@action=redirect&bpo=34969]: gzip: Add –fast, –best on the gzip CLI, these parameters will be used for the fast compression method (quick) or the best method compress (slower, but smaller file). Also, change the default compression level to 6 (tradeoff).

bpo-16965 [https://bugs.python.org/issue?@action=redirect&bpo=16965]: The 2to3 execfile fixer now opens the file with mode 'rb'. Patch by Zackery Spytz.

bpo-34966 [https://bugs.python.org/issue?@action=redirect&bpo=34966]: pydoc now supports aliases not only to methods defined in the end class, but also to inherited methods. The docstring is not duplicated for aliases.

bpo-34926 [https://bugs.python.org/issue?@action=redirect&bpo=34926]: mimetypes.MimeTypes.guess_type() now accepts path-like object in addition to url strings. Patch by Mayank Asthana.

bpo-23831 [https://bugs.python.org/issue?@action=redirect&bpo=23831]: Add moveto() method to the tkinter.Canvas widget. Patch by Juliette Monsel.

bpo-34941 [https://bugs.python.org/issue?@action=redirect&bpo=34941]: Methods find(), findtext() and findall() of the Element class in the xml.etree.ElementTree module are now able to find children which are instances of Element subclasses.

bpo-32680 [https://bugs.python.org/issue?@action=redirect&bpo=32680]: smtplib.SMTP objects now always have a sock attribute present

bpo-34769 [https://bugs.python.org/issue?@action=redirect&bpo=34769]: Fix for async generators not finalizing when event loop is in debug mode and garbage collector runs in another thread.

bpo-34936 [https://bugs.python.org/issue?@action=redirect&bpo=34936]: Fix TclError in tkinter.Spinbox.selection_element(). Patch by Juliette Monsel.

bpo-34829 [https://bugs.python.org/issue?@action=redirect&bpo=34829]: Add methods selection_from, selection_range, selection_present and selection_to to the tkinter.Spinbox for consistency with the tkinter.Entry widget. Patch by Juliette Monsel.

bpo-34911 [https://bugs.python.org/issue?@action=redirect&bpo=34911]: Added secure_protocols argument to http.cookiejar.DefaultCookiePolicy to allow for tweaking of protocols and also to add support by default for wss, the secure websocket protocol.

bpo-34922 [https://bugs.python.org/issue?@action=redirect&bpo=34922]: Fixed integer overflow in the digest() and hexdigest() methods for the SHAKE algorithm in the hashlib module.

bpo-34925 [https://bugs.python.org/issue?@action=redirect&bpo=34925]: 25% speedup in argument parsing for the functions in the bisect module.

bpo-34900 [https://bugs.python.org/issue?@action=redirect&bpo=34900]: Fixed unittest.TestCase.debug() when used to call test methods with subtests. Patch by Bruno Oliveira.

bpo-34844 [https://bugs.python.org/issue?@action=redirect&bpo=34844]: logging.Formatter enhancement - Ensure styles and fmt matches in logging.Formatter - Added validate method in each format style class: StrFormatStyle, PercentStyle, StringTemplateStyle. - This method is called in the constructor of logging.Formatter class - Also re-raise the KeyError in the format method of each style class, so it would a bit clear that it’s an error with the invalid format fields.

bpo-34897 [https://bugs.python.org/issue?@action=redirect&bpo=34897]: Adjust test.support.missing_compiler_executable check so that a nominal command name of “” is ignored. Patch by Michael Felt.

bpo-34871 [https://bugs.python.org/issue?@action=redirect&bpo=34871]: Fix inspect module polluted sys.modules when parsing __text_signature__ of callable.

bpo-34898 [https://bugs.python.org/issue?@action=redirect&bpo=34898]: Add mtime argument to gzip.compress for reproducible output. Patch by Guo Ci Teo.

bpo-28441 [https://bugs.python.org/issue?@action=redirect&bpo=28441]: On Cygwin and MinGW, ensure that sys.executable always includes the full filename in the path, including the .exe suffix (unless it is a symbolic link).

bpo-34866 [https://bugs.python.org/issue?@action=redirect&bpo=34866]: Adding max_num_fields to cgi.FieldStorage to make DOS attacks harder by limiting the number of MiniFieldStorage objects created by FieldStorage.

bpo-34711 [https://bugs.python.org/issue?@action=redirect&bpo=34711]: http.server ensures it reports HTTPStatus.NOT_FOUND when the local path ends with “/” and is not a directory, even if the underlying OS (e.g. AIX) accepts such paths as a valid file reference. Patch by Michael Felt.

bpo-34872 [https://bugs.python.org/issue?@action=redirect&bpo=34872]: Fix self-cancellation in C implementation of asyncio.Task

bpo-34849 [https://bugs.python.org/issue?@action=redirect&bpo=34849]: Don’t log waiting for selector.select in asyncio loop iteration. The waiting is pretty normal for any asyncio program, logging its time just adds a noise to logs without any useful information provided.

bpo-34022 [https://bugs.python.org/issue?@action=redirect&bpo=34022]: The SOURCE_DATE_EPOCH environment variable no longer overrides the value of the invalidation_mode argument to py_compile.compile(), and determines its default value instead.

bpo-34819 [https://bugs.python.org/issue?@action=redirect&bpo=34819]: Use a monotonic clock to compute timeouts in Executor.map() and as_completed(), in order to prevent timeouts from deviating when the system clock is adjusted.

bpo-34758 [https://bugs.python.org/issue?@action=redirect&bpo=34758]: Add .wasm -> application/wasm to list of recognized file types and content type headers

bpo-34789 [https://bugs.python.org/issue?@action=redirect&bpo=34789]: xml.sax.make_parser() now accepts any iterable as its parser_list argument. Patch by Andrés Delfino.

bpo-34334 [https://bugs.python.org/issue?@action=redirect&bpo=34334]: In QueueHandler, clear exc_text from LogRecord to prevent traceback from being written twice.

bpo-34687 [https://bugs.python.org/issue?@action=redirect&bpo=34687]: On Windows, asyncio now uses ProactorEventLoop, instead of SelectorEventLoop, by default.

bpo-5950 [https://bugs.python.org/issue?@action=redirect&bpo=5950]: Support reading zip files with archive comments in zipimport.

bpo-32892 [https://bugs.python.org/issue?@action=redirect&bpo=32892]: The parser now represents all constants as ast.Constant instead of using specific constant AST types (Num, Str, Bytes, NameConstant and Ellipsis). These classes are considered deprecated and will be removed in future Python versions.

bpo-34728 [https://bugs.python.org/issue?@action=redirect&bpo=34728]: Add deprecation warning when loop is used in methods: asyncio.sleep, asyncio.wait and asyncio.wait_for.

bpo-34738 [https://bugs.python.org/issue?@action=redirect&bpo=34738]: ZIP files created by distutils will now include entries for directories.

bpo-34659 [https://bugs.python.org/issue?@action=redirect&bpo=34659]: Add an optional initial argument to itertools.accumulate().

bpo-29577 [https://bugs.python.org/issue?@action=redirect&bpo=29577]: Support multiple mixin classes when creating Enums.

bpo-34670 [https://bugs.python.org/issue?@action=redirect&bpo=34670]: Add SSLContext.post_handshake_auth and SSLSocket.verify_client_post_handshake for TLS 1.3’s post handshake authentication feature.

bpo-32718 [https://bugs.python.org/issue?@action=redirect&bpo=32718]: The Activate.ps1 script from venv works with PowerShell Core 6.1 and is now available under all operating systems.

bpo-31177 [https://bugs.python.org/issue?@action=redirect&bpo=31177]: Fix bug that prevented using reset_mock on mock instances with deleted attributes

bpo-34672 [https://bugs.python.org/issue?@action=redirect&bpo=34672]: Add a workaround, so the 'Z' time.strftime() specifier on the musl C library can work in some cases.

bpo-34666 [https://bugs.python.org/issue?@action=redirect&bpo=34666]: Implement asyncio.StreamWriter.awrite and asyncio.StreamWriter.aclose() coroutines. Methods are needed for providing a consistent stream API with control flow switched on by default.

bpo-6721 [https://bugs.python.org/issue?@action=redirect&bpo=6721]: Acquire the logging module’s commonly used internal locks while fork()ing to avoid deadlocks in the child process.

bpo-34658 [https://bugs.python.org/issue?@action=redirect&bpo=34658]: Fix a rare interpreter unhandled exception state SystemError only seen when using subprocess with a preexec_fn while an after_parent handler has been registered with os.register_at_fork and the fork system call fails.

bpo-34652 [https://bugs.python.org/issue?@action=redirect&bpo=34652]: Ensure os.lchmod() is never defined on Linux.

bpo-34638 [https://bugs.python.org/issue?@action=redirect&bpo=34638]: Store a weak reference to stream reader to break strong references loop between reader and protocol. It allows to detect and close the socket if the stream is deleted (garbage collected) without close() call.

bpo-34536 [https://bugs.python.org/issue?@action=redirect&bpo=34536]: Enum._missing_: raise ValueError if None returned and TypeError if non-member is returned.

bpo-34636 [https://bugs.python.org/issue?@action=redirect&bpo=34636]: Speed up re scanning of many non-matching characters for s w and d within bytes objects. (microoptimization)

bpo-24412 [https://bugs.python.org/issue?@action=redirect&bpo=24412]: Add addModuleCleanup() and addClassCleanup() to unittest to support cleanups for setUpModule() and setUpClass(). Patch by Lisa Roach.

bpo-34630 [https://bugs.python.org/issue?@action=redirect&bpo=34630]: Don’t log SSL certificate errors in asyncio code (connection error logging is skipped already).

bpo-32490 [https://bugs.python.org/issue?@action=redirect&bpo=32490]: Prevent filename duplication in subprocess exception messages. Patch by Zackery Spytz.

bpo-34363 [https://bugs.python.org/issue?@action=redirect&bpo=34363]: dataclasses.asdict() and .astuple() now handle namedtuples correctly.

bpo-34625 [https://bugs.python.org/issue?@action=redirect&bpo=34625]: Update vendorized expat library version to 2.2.6.

bpo-32270 [https://bugs.python.org/issue?@action=redirect&bpo=32270]: The subprocess module no longer mistakenly closes redirected fds even when they were in pass_fds when outside of the default {0, 1, 2} set.

bpo-34622 [https://bugs.python.org/issue?@action=redirect&bpo=34622]: Create a dedicated asyncio.CancelledError, asyncio.InvalidStateError and asyncio.TimeoutError exception classes. Inherit them from corresponding exceptions from concurrent.futures package. Extract asyncio exceptions into a separate file.

bpo-34610 [https://bugs.python.org/issue?@action=redirect&bpo=34610]: Fixed iterator of multiprocessing.managers.DictProxy.

bpo-34421 [https://bugs.python.org/issue?@action=redirect&bpo=34421]: Fix distutils logging for non-ASCII strings. This caused installation issues on Windows.

bpo-34604 [https://bugs.python.org/issue?@action=redirect&bpo=34604]: Fix possible mojibake in the error message of pwd.getpwnam and grp.getgrnam using string representation because of invisible characters or trailing whitespaces. Patch by William Grzybowski.

bpo-30977 [https://bugs.python.org/issue?@action=redirect&bpo=30977]: Make uuid.UUID use __slots__ to reduce its memory footprint. Based on original patch by Wouter Bolsterlee.

bpo-34574 [https://bugs.python.org/issue?@action=redirect&bpo=34574]: OrderedDict iterators are not exhausted during pickling anymore. Patch by Sergey Fedoseev.

bpo-8110 [https://bugs.python.org/issue?@action=redirect&bpo=8110]: Refactored subprocess to check for Windows-specific modules rather than sys.platform == 'win32'.

bpo-34530 [https://bugs.python.org/issue?@action=redirect&bpo=34530]: distutils.spawn.find_executable() now falls back on os.defpath if the PATH environment variable is not set.

bpo-34563 [https://bugs.python.org/issue?@action=redirect&bpo=34563]: On Windows, fix multiprocessing.Connection for very large read: fix _winapi.PeekNamedPipe() and _winapi.ReadFile() for read larger than INT_MAX (usually 2**31-1).

bpo-34558 [https://bugs.python.org/issue?@action=redirect&bpo=34558]: Correct typo in Lib/ctypes/_aix.py

bpo-34282 [https://bugs.python.org/issue?@action=redirect&bpo=34282]: Move Enum._convert to EnumMeta._convert_ and fix enum members getting shadowed by parent attributes.

bpo-22872 [https://bugs.python.org/issue?@action=redirect&bpo=22872]: When the queue is closed, ValueError is now raised by multiprocessing.Queue.put() and multiprocessing.Queue.get() instead of AssertionError and OSError, respectively. Patch by Zackery Spytz.

bpo-34515 [https://bugs.python.org/issue?@action=redirect&bpo=34515]: Fix parsing non-ASCII identifiers in lib2to3.pgen2.tokenize (PEP 3131 [https://peps.python.org/pep-3131/]).

bpo-13312 [https://bugs.python.org/issue?@action=redirect&bpo=13312]: Avoids a possible integer underflow (undefined behavior) in the time module’s year handling code when passed a very low negative year value.

bpo-34472 [https://bugs.python.org/issue?@action=redirect&bpo=34472]: Improved compatibility for streamed files in zipfile. Previously an optional signature was not being written and certain ZIP applications were not supported. Patch by Silas Sewell.

bpo-34454 [https://bugs.python.org/issue?@action=redirect&bpo=34454]: Fix the .fromisoformat() methods of datetime types crashing when given unicode with non-UTF-8-encodable code points. Specifically, datetime.fromisoformat() now accepts surrogate unicode code points used as the separator. Report and tests by Alexey Izbyshev, patch by Paul Ganssle.

bpo-6700 [https://bugs.python.org/issue?@action=redirect&bpo=6700]: Fix inspect.getsourcelines for module level frames/tracebacks. Patch by Vladimir Matveev.

bpo-34171 [https://bugs.python.org/issue?@action=redirect&bpo=34171]: Running the trace module no longer creates the trace.cover file.

bpo-34441 [https://bugs.python.org/issue?@action=redirect&bpo=34441]: Fix crash when an ABC-derived class with invalid __subclasses__ is passed as the second argument to issubclass(). Patch by Alexey Izbyshev.

bpo-34427 [https://bugs.python.org/issue?@action=redirect&bpo=34427]: Fix infinite loop in a.extend(a) for MutableSequence subclasses.

bpo-34412 [https://bugs.python.org/issue?@action=redirect&bpo=34412]: Make signal.strsignal() work on HP-UX. Patch by Michael Osipov.

bpo-20849 [https://bugs.python.org/issue?@action=redirect&bpo=20849]: shutil.copytree now accepts a new dirs_exist_ok keyword argument. Patch by Josh Bronson.

bpo-31715 [https://bugs.python.org/issue?@action=redirect&bpo=31715]: Associate .mjs file extension with application/javascript MIME Type.

bpo-34384 [https://bugs.python.org/issue?@action=redirect&bpo=34384]: os.readlink() now accepts path-like and bytes objects on Windows.

bpo-22602 [https://bugs.python.org/issue?@action=redirect&bpo=22602]: The UTF-7 decoder now raises UnicodeDecodeError for ill-formed sequences starting with “+” (as specified in RFC 2152). Patch by Zackery Spytz.

bpo-2122 [https://bugs.python.org/issue?@action=redirect&bpo=2122]: The mmap.flush() method now returns None on success, raises an exception on error under all platforms.

bpo-34341 [https://bugs.python.org/issue?@action=redirect&bpo=34341]: Appending to the ZIP archive with the ZIP64 extension no longer grows the size of extra fields of existing entries.

bpo-34333 [https://bugs.python.org/issue?@action=redirect&bpo=34333]: Fix %-formatting in pathlib.PurePath.with_suffix() when formatting an error message.

bpo-18540 [https://bugs.python.org/issue?@action=redirect&bpo=18540]: The imaplib.IMAP4 and imaplib.IMAP4_SSL classes now resolve to the local host IP correctly when the default value of host parameter ('') is used.

bpo-26502 [https://bugs.python.org/issue?@action=redirect&bpo=26502]: Implement traceback.FrameSummary.__len__() method to preserve compatibility with the old tuple API.

bpo-34318 [https://bugs.python.org/issue?@action=redirect&bpo=34318]: assertRaises(), assertRaisesRegex(), assertWarns() and assertWarnsRegex() no longer success if the passed callable is None. They no longer ignore unknown keyword arguments in the context manager mode. A DeprecationWarning was raised in these cases since Python 3.5.

bpo-9372 [https://bugs.python.org/issue?@action=redirect&bpo=9372]: Deprecate __getitem__() methods of xml.dom.pulldom.DOMEventStream, wsgiref.util.FileWrapper and fileinput.FileInput.

bpo-33613 [https://bugs.python.org/issue?@action=redirect&bpo=33613]: Fix a race condition in multiprocessing.semaphore_tracker when the tracker receives SIGINT before it can register signal handlers for ignoring it.

bpo-34248 [https://bugs.python.org/issue?@action=redirect&bpo=34248]: Report filename in the exception raised when the database file cannot be opened by dbm.gnu.open() and dbm.ndbm.open() due to OS-related error. Patch by Zsolt Cserna.

bpo-33089 [https://bugs.python.org/issue?@action=redirect&bpo=33089]: Add math.dist() to compute the Euclidean distance between two points.

bpo-34246 [https://bugs.python.org/issue?@action=redirect&bpo=34246]: smtplib.SMTP.send_message() no longer modifies the content of the mail_options argument. Patch by Pablo S. Blum de Aguiar.

bpo-31047 [https://bugs.python.org/issue?@action=redirect&bpo=31047]: Fix ntpath.abspath for invalid paths on windows. Patch by Franz Woellert.

bpo-32321 [https://bugs.python.org/issue?@action=redirect&bpo=32321]: Add pure Python fallback for functools.reduce. Patch by Robert Wright.

bpo-34270 [https://bugs.python.org/issue?@action=redirect&bpo=34270]: The default asyncio task class now always has a name which can be get or set using two new methods (get_name() and set_name()) and is visible in the repr() output. An initial name can also be set using the new name keyword argument to asyncio.create_task() or the create_task() method of the event loop. If no initial name is set, the default Task implementation generates a name like Task-1 using a monotonic counter.

bpo-34263 [https://bugs.python.org/issue?@action=redirect&bpo=34263]: asyncio’s event loop will not pass timeouts longer than one day to epoll/select etc.

bpo-34035 [https://bugs.python.org/issue?@action=redirect&bpo=34035]: Fix several AttributeError in zipfile seek() methods. Patch by Mickaël Schoentgen.

bpo-32215 [https://bugs.python.org/issue?@action=redirect&bpo=32215]: Fix performance regression in sqlite3 when a DML statement appeared in a different line than the rest of the SQL query.

bpo-34075 [https://bugs.python.org/issue?@action=redirect&bpo=34075]: Deprecate passing non-ThreadPoolExecutor instances to AbstractEventLoop.set_default_executor().

bpo-34251 [https://bugs.python.org/issue?@action=redirect&bpo=34251]: Restore msilib.Win64 to preserve backwards compatibility since it’s already used by distutils’ bdist_msi command.

bpo-19891 [https://bugs.python.org/issue?@action=redirect&bpo=19891]: Ignore errors caused by missing / non-writable homedir while writing history during exit of an interactive session. Patch by Anthony Sottile.

bpo-33089 [https://bugs.python.org/issue?@action=redirect&bpo=33089]: Enhanced math.hypot() to support more than two dimensions.

bpo-34228 [https://bugs.python.org/issue?@action=redirect&bpo=34228]: tracemalloc: PYTHONTRACEMALLOC=0 environment variable and -X tracemalloc=0 command line option are now allowed to disable explicitly tracemalloc at startup.

bpo-13041 [https://bugs.python.org/issue?@action=redirect&bpo=13041]: Use shutil.get_terminal_size() to calculate the terminal width correctly in the argparse.HelpFormatter class. Initial patch by Zbyszek Jędrzejewski-Szmek.

bpo-34213 [https://bugs.python.org/issue?@action=redirect&bpo=34213]: Allow frozen dataclasses to have a field named “object”. Previously this conflicted with an internal use of “object”.

bpo-34052 [https://bugs.python.org/issue?@action=redirect&bpo=34052]: sqlite3.Connection.create_aggregate(), sqlite3.Connection.create_function(), sqlite3.Connection.set_authorizer(), sqlite3.Connection.set_progress_handler() methods raises TypeError when unhashable objects are passed as callable. These methods now don’t pass such objects to SQLite API. Previous behavior could lead to segfaults. Patch by Sergey Fedoseev.

bpo-34197 [https://bugs.python.org/issue?@action=redirect&bpo=34197]: Attributes skipinitialspace, doublequote and strict of the dialect attribute of the csv reader are now bool instances instead of integers 0 or 1.

bpo-32788 [https://bugs.python.org/issue?@action=redirect&bpo=32788]: Errors other than TypeError raised in methods __adapt__() and __conform__() in the sqlite3 module are now propagated to the user.

bpo-21446 [https://bugs.python.org/issue?@action=redirect&bpo=21446]: The reload fixer now uses importlib.reload() instead of deprecated imp.reload().

bpo-940286 [https://bugs.python.org/issue?@action=redirect&bpo=940286]: pydoc’s Helper.showtopic() method now prints the cross references of a topic correctly.

bpo-34164 [https://bugs.python.org/issue?@action=redirect&bpo=34164]: base64.b32decode() could raise UnboundLocalError or OverflowError for incorrect padding. Now it always raises base64.Error in these cases.

bpo-33729 [https://bugs.python.org/issue?@action=redirect&bpo=33729]: Fixed issues with arguments parsing in hashlib.

bpo-34097 [https://bugs.python.org/issue?@action=redirect&bpo=34097]: ZipFile can zip files older than 1980-01-01 and newer than 2107-12-31 using a new strict_timestamps parameter at the cost of setting the timestamp to the limit.

bpo-34108 [https://bugs.python.org/issue?@action=redirect&bpo=34108]: Remove extraneous CR in 2to3 refactor.

bpo-34070 [https://bugs.python.org/issue?@action=redirect&bpo=34070]: Make sure to only check if the handle is a tty, when opening a file with buffering=-1.

bpo-27494 [https://bugs.python.org/issue?@action=redirect&bpo=27494]: Reverted bpo-27494 [https://bugs.python.org/issue?@action=redirect&bpo=27494]. 2to3 rejects now a trailing comma in generator expressions.

bpo-33967 [https://bugs.python.org/issue?@action=redirect&bpo=33967]: functools.singledispatch now raises TypeError instead of IndexError when no positional arguments are passed.

bpo-34041 [https://bugs.python.org/issue?@action=redirect&bpo=34041]: Add the parameter deterministic to the sqlite3.Connection.create_function() method. Patch by Sergey Fedoseev.

bpo-34056 [https://bugs.python.org/issue?@action=redirect&bpo=34056]: Ensure the loader shim created by imp.load_module always returns bytes from its get_data() function. This fixes using imp.load_module with PEP 552 [https://peps.python.org/pep-0552/] hash-based pycs.

bpo-34054 [https://bugs.python.org/issue?@action=redirect&bpo=34054]: The multiprocessing module now uses the monotonic clock time.monotonic() instead of the system clock time.time() to implement timeout.

bpo-34043 [https://bugs.python.org/issue?@action=redirect&bpo=34043]: Optimize tarfile uncompress performance about 15% when gzip is used.

bpo-34044 [https://bugs.python.org/issue?@action=redirect&bpo=34044]: subprocess.Popen now copies the startupinfo argument to leave it unchanged: it will modify the copy, so that the same STARTUPINFO object can be used multiple times.

bpo-34010 [https://bugs.python.org/issue?@action=redirect&bpo=34010]: Fixed a performance regression for reading streams with tarfile. The buffered read should use a list, instead of appending to a bytes object.

bpo-34019 [https://bugs.python.org/issue?@action=redirect&bpo=34019]: webbrowser: Correct the arguments passed to Opera Browser when opening a new URL using the webbrowser module. Patch by Bumsik Kim.

bpo-34003 [https://bugs.python.org/issue?@action=redirect&bpo=34003]: csv.DictReader now creates dicts instead of OrderedDicts. Patch by Michael Selik.

bpo-33978 [https://bugs.python.org/issue?@action=redirect&bpo=33978]: Closed existing logging handlers before reconfiguration via fileConfig and dictConfig. Patch by Karthikeyan Singaravelan.

bpo-14117 [https://bugs.python.org/issue?@action=redirect&bpo=14117]: Make minor tweaks to turtledemo. The ‘wikipedia’ example is now ‘rosette’, describing what it draws. The ‘penrose’ print output is reduced. The’1024’ output of ‘tree’ is eliminated.

bpo-33974 [https://bugs.python.org/issue?@action=redirect&bpo=33974]: Fixed passing lists and tuples of strings containing special characters ", \, {, } and \n as options to ttk widgets.

bpo-27500 [https://bugs.python.org/issue?@action=redirect&bpo=27500]: Fix getaddrinfo to resolve IPv6 addresses correctly.

bpo-24567 [https://bugs.python.org/issue?@action=redirect&bpo=24567]: Improve random.choices() to handle subnormal input weights that could occasionally trigger an IndexError.

bpo-33871 [https://bugs.python.org/issue?@action=redirect&bpo=33871]: Fixed integer overflow in os.readv(), os.writev(), os.preadv() and os.pwritev() and in os.sendfile() with headers or trailers arguments (on BSD-based OSes and macOS).

bpo-25007 [https://bugs.python.org/issue?@action=redirect&bpo=25007]: Add copy.copy() and copy.deepcopy() support to zlib compressors and decompressors. Patch by Zackery Spytz.

bpo-33929 [https://bugs.python.org/issue?@action=redirect&bpo=33929]: multiprocessing: Fix a race condition in Popen of multiprocessing.popen_spawn_win32. The child process now duplicates the read end of pipe instead of “stealing” it. Previously, the read end of pipe was “stolen” by the child process, but it leaked a handle if the child process had been terminated before it could steal the handle from the parent process.

bpo-33899 [https://bugs.python.org/issue?@action=redirect&bpo=33899]: Tokenize module now implicitly emits a NEWLINE when provided with input that does not have a trailing new line. This behavior now matches what the C tokenizer does internally. Contributed by Ammar Askar.

bpo-33897 [https://bugs.python.org/issue?@action=redirect&bpo=33897]: Added a ‘force’ keyword argument to logging.basicConfig().

bpo-33695 [https://bugs.python.org/issue?@action=redirect&bpo=33695]: shutil.copytree() uses os.scandir() function and all copy functions depending from it use cached os.stat() values. The speedup for copying a directory with 8000 files is around +9% on Linux, +20% on Windows and + 30% on a Windows SMB share. Also the number of os.stat() syscalls is reduced by 38% making shutil.copytree() especially faster on network filesystems. (Contributed by Giampaolo Rodola’ in bpo-33695 [https://bugs.python.org/issue?@action=redirect&bpo=33695].)

bpo-33916 [https://bugs.python.org/issue?@action=redirect&bpo=33916]: bz2 and lzma: When Decompressor.__init__() is called twice, free the old lock to not leak memory.

bpo-32568 [https://bugs.python.org/issue?@action=redirect&bpo=32568]: Make select.epoll() and its documentation consistent regarding sizehint and flags.

bpo-33833 [https://bugs.python.org/issue?@action=redirect&bpo=33833]: Fixed bug in asyncio where ProactorSocketTransport logs AssertionError if force closed during write.

bpo-33663 [https://bugs.python.org/issue?@action=redirect&bpo=33663]: Convert content length to string before putting to header.

bpo-33721 [https://bugs.python.org/issue?@action=redirect&bpo=33721]: os.path functions that return a boolean result like exists(), lexists(), isdir(), isfile(), islink(), and ismount(), and pathlib.Path methods that return a boolean result like exists(), is_dir(), is_file(), is_mount(), is_symlink(), is_block_device(), is_char_device(), is_fifo(), is_socket() now return False instead of raising ValueError or its subclasses UnicodeEncodeError and UnicodeDecodeError for paths that contain characters or bytes unrepresentable at the OS level.

bpo-26544 [https://bugs.python.org/issue?@action=redirect&bpo=26544]: Fixed implementation of platform.libc_ver(). It almost always returned version ‘2.9’ for glibc.

bpo-33843 [https://bugs.python.org/issue?@action=redirect&bpo=33843]: Remove deprecated cgi.escape, cgi.parse_qs and cgi.parse_qsl.

bpo-33842 [https://bugs.python.org/issue?@action=redirect&bpo=33842]: Remove tarfile.filemode which is deprecated since Python 3.3.

bpo-30167 [https://bugs.python.org/issue?@action=redirect&bpo=30167]: Prevent site.main() exception if PYTHONSTARTUP is set. Patch by Steve Weber.

bpo-33805 [https://bugs.python.org/issue?@action=redirect&bpo=33805]: Improve error message of dataclasses.replace() when an InitVar is not specified

bpo-33687 [https://bugs.python.org/issue?@action=redirect&bpo=33687]: Fix the call to os.chmod() for uu.decode() if a mode is given or decoded. Patch by Timo Furrer.

bpo-33812 [https://bugs.python.org/issue?@action=redirect&bpo=33812]: Datetime instance d with non-None tzinfo, but with d.tzinfo.utcoffset(d) returning None is now treated as naive by the astimezone() method.

bpo-32108 [https://bugs.python.org/issue?@action=redirect&bpo=32108]: In configparser, don’t clear section when it is assigned to itself.

bpo-27397 [https://bugs.python.org/issue?@action=redirect&bpo=27397]: Make email module properly handle invalid-length base64 strings.

bpo-33578 [https://bugs.python.org/issue?@action=redirect&bpo=33578]: Implement multibyte encoder/decoder state methods

bpo-30805 [https://bugs.python.org/issue?@action=redirect&bpo=30805]: Avoid race condition with debug logging

bpo-33476 [https://bugs.python.org/issue?@action=redirect&bpo=33476]: Fix _header_value_parser.py when address group is missing final ‘;’. Contributed by Enrique Perez-Terron

bpo-33694 [https://bugs.python.org/issue?@action=redirect&bpo=33694]: asyncio: Fix a race condition causing data loss on pause_reading()/resume_reading() when using the ProactorEventLoop.

bpo-32493 [https://bugs.python.org/issue?@action=redirect&bpo=32493]: Correct test for uuid_enc_be availability in configure.ac. Patch by Michael Felt.

bpo-33792 [https://bugs.python.org/issue?@action=redirect&bpo=33792]: Add asyncio.WindowsSelectorEventLoopPolicy and asyncio.WindowsProactorEventLoopPolicy.

bpo-33274 [https://bugs.python.org/issue?@action=redirect&bpo=33274]: W3C DOM Level 1 specifies return value of Element.removeAttributeNode() as “The Attr node that was removed.” xml.dom.minidom now complies with this requirement.

bpo-33778 [https://bugs.python.org/issue?@action=redirect&bpo=33778]: Update unicodedata’s database to Unicode version 11.0.0.

bpo-33165 [https://bugs.python.org/issue?@action=redirect&bpo=33165]: Added a stacklevel parameter to logging calls to allow use of wrapper/helper functions for logging APIs.

bpo-33770 [https://bugs.python.org/issue?@action=redirect&bpo=33770]: improve base64 exception message for encoded inputs of invalid length

bpo-33769 [https://bugs.python.org/issue?@action=redirect&bpo=33769]: asyncio/start_tls: Fix error message; cancel callbacks in case of an unhandled error; mark SSLTransport as closed if it is aborted.

bpo-33767 [https://bugs.python.org/issue?@action=redirect&bpo=33767]: The concatenation (+) and repetition (*) sequence operations now raise TypeError instead of SystemError when performed on mmap.mmap objects. Patch by Zackery Spytz.

bpo-33734 [https://bugs.python.org/issue?@action=redirect&bpo=33734]: asyncio/ssl: Fix AttributeError, increase default handshake timeout

bpo-31014 [https://bugs.python.org/issue?@action=redirect&bpo=31014]: Fixed creating a controller for webbrowser when a user specifies a path to an entry in the BROWSER environment variable. Based on patch by John Still.

bpo-2504 [https://bugs.python.org/issue?@action=redirect&bpo=2504]: Add gettext.pgettext() and variants.

bpo-33197 [https://bugs.python.org/issue?@action=redirect&bpo=33197]: Add description property for _ParameterKind

bpo-32751 [https://bugs.python.org/issue?@action=redirect&bpo=32751]: When cancelling the task due to a timeout, asyncio.wait_for() will now wait until the cancellation is complete.

bpo-32684 [https://bugs.python.org/issue?@action=redirect&bpo=32684]: Fix gather to propagate cancellation of itself even with return_exceptions.

bpo-33654 [https://bugs.python.org/issue?@action=redirect&bpo=33654]: Support protocol type switching in SSLTransport.set_protocol().

bpo-33674 [https://bugs.python.org/issue?@action=redirect&bpo=33674]: Pause the transport as early as possible to further reduce the risk of data_received() being called before connection_made().

bpo-33671 [https://bugs.python.org/issue?@action=redirect&bpo=33671]: shutil.copyfile(), shutil.copy(), shutil.copy2(), shutil.copytree() and shutil.move() use platform-specific fast-copy syscalls on Linux and macOS in order to copy the file more efficiently. On Windows shutil.copyfile() uses a bigger default buffer size (1 MiB instead of 16 KiB) and a memoryview()-based variant of shutil.copyfileobj() is used. The speedup for copying a 512MiB file is about +26% on Linux, +50% on macOS and +40% on Windows. Also, much less CPU cycles are consumed. (Contributed by Giampaolo Rodola’ in bpo-25427 [https://bugs.python.org/issue?@action=redirect&bpo=25427].)

bpo-33674 [https://bugs.python.org/issue?@action=redirect&bpo=33674]: Fix a race condition in SSLProtocol.connection_made() of asyncio.sslproto: start immediately the handshake instead of using call_soon(). Previously, data_received() could be called before the handshake started, causing the handshake to hang or fail.

bpo-31647 [https://bugs.python.org/issue?@action=redirect&bpo=31647]: Fixed bug where calling write_eof() on a _SelectorSocketTransport after it’s already closed raises AttributeError.

bpo-32610 [https://bugs.python.org/issue?@action=redirect&bpo=32610]: Make asyncio.all_tasks() return only pending tasks.

bpo-32410 [https://bugs.python.org/issue?@action=redirect&bpo=32410]: Avoid blocking on file IO in sendfile fallback code

bpo-33469 [https://bugs.python.org/issue?@action=redirect&bpo=33469]: Fix RuntimeError after closing loop that used run_in_executor

bpo-33672 [https://bugs.python.org/issue?@action=redirect&bpo=33672]: Fix Task.__repr__ crash with Cython’s bogus coroutines

bpo-33654 [https://bugs.python.org/issue?@action=redirect&bpo=33654]: Fix transport.set_protocol() to support switching between asyncio.Protocol and asyncio.BufferedProtocol. Fix loop.start_tls() to work with asyncio.BufferedProtocols.

bpo-33652 [https://bugs.python.org/issue?@action=redirect&bpo=33652]: Pickles of type variables and subscripted generics are now future-proof and compatible with older Python versions.

bpo-32493 [https://bugs.python.org/issue?@action=redirect&bpo=32493]: Fixed uuid.uuid1() on FreeBSD.

bpo-33238 [https://bugs.python.org/issue?@action=redirect&bpo=33238]: Add InvalidStateError to concurrent.futures. Future.set_result and Future.set_exception now raise InvalidStateError if the futures are not pending or running. Patch by Jason Haydaman.

bpo-33618 [https://bugs.python.org/issue?@action=redirect&bpo=33618]: Finalize and document preliminary and experimental TLS 1.3 support with OpenSSL 1.1.1

bpo-33625 [https://bugs.python.org/issue?@action=redirect&bpo=33625]: Release GIL on grp.getgrnam, grp.getgrgid, pwd.getpwnam and pwd.getpwuid if reentrant variants of these functions are available. Patch by William Grzybowski.

bpo-33623 [https://bugs.python.org/issue?@action=redirect&bpo=33623]: Fix possible SIGSGV when asyncio.Future is created in __del__

bpo-11874 [https://bugs.python.org/issue?@action=redirect&bpo=11874]: Use a better regex when breaking usage into wrappable parts. Avoids bogus assertion errors from custom metavar strings.

bpo-30877 [https://bugs.python.org/issue?@action=redirect&bpo=30877]: Fixed a bug in the Python implementation of the JSON decoder that prevented the cache of parsed strings from clearing after finishing the decoding. Based on patch by c-fos.

bpo-33604 [https://bugs.python.org/issue?@action=redirect&bpo=33604]: Remove HMAC default to md5 marked for removal in 3.8 (removal originally planned in 3.6, bump to 3.8 in PR 7062).

bpo-33582 [https://bugs.python.org/issue?@action=redirect&bpo=33582]: Emit a deprecation warning for inspect.formatargspec

bpo-21145 [https://bugs.python.org/issue?@action=redirect&bpo=21145]: Add functools.cached_property decorator, for computed properties cached for the life of the instance.

bpo-33570 [https://bugs.python.org/issue?@action=redirect&bpo=33570]: Change TLS 1.3 cipher suite settings for compatibility with OpenSSL 1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3 ciphers enabled by default.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Do not simplify arguments to typing.Union. Now Union[Manager, Employee] is not simplified to Employee at runtime. Such simplification previously caused several bugs and limited possibilities for introspection.

bpo-12486 [https://bugs.python.org/issue?@action=redirect&bpo=12486]: tokenize.generate_tokens() is now documented as a public API to tokenize unicode strings. It was previously present but undocumented.

bpo-33540 [https://bugs.python.org/issue?@action=redirect&bpo=33540]: Add a new block_on_close class attribute to ForkingMixIn and ThreadingMixIn classes of socketserver.

bpo-33548 [https://bugs.python.org/issue?@action=redirect&bpo=33548]: tempfile._candidate_tempdir_list should consider common TEMP locations

bpo-33109 [https://bugs.python.org/issue?@action=redirect&bpo=33109]: argparse subparsers are once again not required by default, reverting the change in behavior introduced by bpo-26510 [https://bugs.python.org/issue?@action=redirect&bpo=26510] in 3.7.0a2.

bpo-33541 [https://bugs.python.org/issue?@action=redirect&bpo=33541]: Remove unused private method _strptime.LocaleTime.__pad (a.k.a. _LocaleTime__pad).

bpo-33536 [https://bugs.python.org/issue?@action=redirect&bpo=33536]: dataclasses.make_dataclass now checks for invalid field names and duplicate fields. Also, added a check for invalid field specifications.

bpo-33542 [https://bugs.python.org/issue?@action=redirect&bpo=33542]: Prevent uuid.get_node from using a DUID instead of a MAC on Windows. Patch by Zvi Effron

bpo-26819 [https://bugs.python.org/issue?@action=redirect&bpo=26819]: Fix race condition with ReadTransport.resume_reading in Windows proactor event loop.

Fix failure in typing.get_type_hints() when ClassVar was provided as a string forward reference.

bpo-33516 [https://bugs.python.org/issue?@action=redirect&bpo=33516]: unittest.mock.MagicMock now supports the __round__ magic method.

bpo-28612 [https://bugs.python.org/issue?@action=redirect&bpo=28612]: Added support for Site Maps to urllib’s RobotFileParser as RobotFileParser.site_maps(). Patch by Lady Red, based on patch by Peter Wirtz.

bpo-28167 [https://bugs.python.org/issue?@action=redirect&bpo=28167]: Remove platform.linux_distribution, which was deprecated since 3.5.

bpo-33504 [https://bugs.python.org/issue?@action=redirect&bpo=33504]: Switch the default dictionary implementation for configparser from collections.OrderedDict to the standard dict type.

bpo-33505 [https://bugs.python.org/issue?@action=redirect&bpo=33505]: Optimize asyncio.ensure_future() by reordering if checks: 1.17x faster.

bpo-33497 [https://bugs.python.org/issue?@action=redirect&bpo=33497]: Add errors param to cgi.parse_multipart and make an encoding in FieldStorage use the given errors (needed for Twisted). Patch by Amber Brown.

bpo-29235 [https://bugs.python.org/issue?@action=redirect&bpo=29235]: The cProfile.Profile class can now be used as a context manager. Patch by Scott Sanderson.

bpo-33495 [https://bugs.python.org/issue?@action=redirect&bpo=33495]: Change dataclasses.Fields repr to use the repr of each of its members, instead of str. This makes it more clear what each field actually represents. This is especially true for the ‘type’ member.

bpo-26103 [https://bugs.python.org/issue?@action=redirect&bpo=26103]: Correct inspect.isdatadescriptor to look for __set__ or __delete__. Patch by Aaron Hall.

bpo-29209 [https://bugs.python.org/issue?@action=redirect&bpo=29209]: Removed the doctype() method and the html parameter of the constructor of XMLParser. The doctype() method defined in a subclass will no longer be called. Deprecated methods getchildren() and getiterator() in the ElementTree module emit now a DeprecationWarning instead of PendingDeprecationWarning.

bpo-33453 [https://bugs.python.org/issue?@action=redirect&bpo=33453]: Fix dataclasses to work if using literal string type annotations or if using PEP 563 “Postponed Evaluation of Annotations”. Only specific string prefixes are detected for both ClassVar (“ClassVar” and “typing.ClassVar”) and InitVar (“InitVar” and “dataclasses.InitVar”).

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Minor fixes in typing module: add annotations to NamedTuple.__new__, pass *args and **kwds in Generic.__new__. Original PRs by Paulius Šarka and Chad Dombrova.

bpo-33365 [https://bugs.python.org/issue?@action=redirect&bpo=33365]: Print the header values besides the header keys instead just the header keys if debuglevel is set to >0 in http.client. Patch by Marco Strigl.

bpo-20087 [https://bugs.python.org/issue?@action=redirect&bpo=20087]: Updated alias mapping with glibc 2.27 supported locales.

bpo-33422 [https://bugs.python.org/issue?@action=redirect&bpo=33422]: Fix trailing quotation marks getting deleted when looking up byte/string literals on pydoc. Patch by Andrés Delfino.

bpo-28167 [https://bugs.python.org/issue?@action=redirect&bpo=28167]: The function platform.linux_distribution and platform.dist now trigger a DeprecationWarning and have been marked for removal in Python 3.8

bpo-33281 [https://bugs.python.org/issue?@action=redirect&bpo=33281]: Fix ctypes.util.find_library regression on macOS.

bpo-33311 [https://bugs.python.org/issue?@action=redirect&bpo=33311]: Text and html output generated by cgitb does not display parentheses if the current call is done directly in the module. Patch by Stéphane Blondon.

bpo-27300 [https://bugs.python.org/issue?@action=redirect&bpo=27300]: The file classes in tempfile now accept an errors parameter that complements the already existing encoding. Patch by Stephan Hohe.

bpo-32933 [https://bugs.python.org/issue?@action=redirect&bpo=32933]: unittest.mock.mock_open() now supports iteration over the file contents. Patch by Tony Flury.

bpo-33217 [https://bugs.python.org/issue?@action=redirect&bpo=33217]: Raise TypeError when looking up non-Enum objects in Enum classes and Enum members.

bpo-33197 [https://bugs.python.org/issue?@action=redirect&bpo=33197]: Update error message when constructing invalid inspect.Parameters Patch by Donghee Na.

bpo-33383 [https://bugs.python.org/issue?@action=redirect&bpo=33383]: Fixed crash in the get() method of the dbm.ndbm database object when it is called with a single argument.

bpo-33375 [https://bugs.python.org/issue?@action=redirect&bpo=33375]: The warnings module now finds the Python file associated with a warning from the code object, rather than the frame’s global namespace. This is consistent with how tracebacks and pdb find filenames, and should work better for dynamically executed code.

bpo-33336 [https://bugs.python.org/issue?@action=redirect&bpo=33336]: imaplib now allows MOVE command in IMAP4.uid() (RFC 6851: IMAP MOVE Extension) and potentially as a name of supported method of IMAP4 object.

bpo-32455 [https://bugs.python.org/issue?@action=redirect&bpo=32455]: Added jump parameter to dis.stack_effect().

bpo-27485 [https://bugs.python.org/issue?@action=redirect&bpo=27485]: Rename and deprecate undocumented functions in urllib.parse().

bpo-33332 [https://bugs.python.org/issue?@action=redirect&bpo=33332]: Add signal.valid_signals() to expose the POSIX sigfillset() functionality.

bpo-33251 [https://bugs.python.org/issue?@action=redirect&bpo=33251]: ConfigParser.items() was fixed so that key-value pairs passed in via vars() are not included in the resulting output.

bpo-33329 [https://bugs.python.org/issue?@action=redirect&bpo=33329]: Fix multiprocessing regression on newer glibcs

bpo-33334 [https://bugs.python.org/issue?@action=redirect&bpo=33334]: dis.stack_effect() now supports all defined opcodes including NOP and EXTENDED_ARG.

bpo-991266 [https://bugs.python.org/issue?@action=redirect&bpo=991266]: Fix quoting of the Comment attribute of http.cookies.SimpleCookie.

bpo-33131 [https://bugs.python.org/issue?@action=redirect&bpo=33131]: Upgrade bundled version of pip to 10.0.1.

bpo-33308 [https://bugs.python.org/issue?@action=redirect&bpo=33308]: Fixed a crash in the parser module when converting an ST object to a tree of tuples or lists with line_info=False and col_info=True.

bpo-23403 [https://bugs.python.org/issue?@action=redirect&bpo=23403]: lib2to3 now uses pickle protocol 4 for pre-computed grammars.

bpo-33266 [https://bugs.python.org/issue?@action=redirect&bpo=33266]: lib2to3 now recognizes rf'...' strings.

bpo-11594 [https://bugs.python.org/issue?@action=redirect&bpo=11594]: Ensure line-endings are respected when using lib2to3.

bpo-33254 [https://bugs.python.org/issue?@action=redirect&bpo=33254]: Have importlib.resources.contents() and importlib.abc.ResourceReader.contents() return an iterable instead of an iterator.

bpo-33265 [https://bugs.python.org/issue?@action=redirect&bpo=33265]: contextlib.ExitStack and contextlib.AsyncExitStack now use a method instead of a wrapper function for exit callbacks.

bpo-33263 [https://bugs.python.org/issue?@action=redirect&bpo=33263]: Fix FD leak in _SelectorSocketTransport Patch by Vlad Starostin.

bpo-33256 [https://bugs.python.org/issue?@action=redirect&bpo=33256]: Fix display of <module> call in the html produced by cgitb.html(). Patch by Stéphane Blondon.

bpo-33144 [https://bugs.python.org/issue?@action=redirect&bpo=33144]: random.Random() and its subclassing mechanism got optimized to check only once at class/subclass instantiation time whether its getrandbits() method can be relied on by other methods, including randrange(), for the generation of arbitrarily large random integers. Patch by Wolfgang Maier.

bpo-33185 [https://bugs.python.org/issue?@action=redirect&bpo=33185]: Fixed regression when running pydoc with the -m switch. (The regression was introduced in 3.7.0b3 by the resolution of bpo-33053 [https://bugs.python.org/issue?@action=redirect&bpo=33053])

This fix also changed pydoc to add os.getcwd() to sys.path when necessary, rather than adding ".".

bpo-29613 [https://bugs.python.org/issue?@action=redirect&bpo=29613]: Added support for the SameSite cookie flag to the http.cookies module.

bpo-33169 [https://bugs.python.org/issue?@action=redirect&bpo=33169]: Delete entries of None in sys.path_importer_cache when importlib.machinery.invalidate_caches() is called.

bpo-33203 [https://bugs.python.org/issue?@action=redirect&bpo=33203]: random.Random.choice() now raises IndexError for empty sequences consistently even when called from subclasses without a getrandbits() implementation.

bpo-33224 [https://bugs.python.org/issue?@action=redirect&bpo=33224]: Update difflib.mdiff() for PEP 479 [https://peps.python.org/pep-0479/]. Convert an uncaught StopIteration in a generator into a return-statement.

bpo-33209 [https://bugs.python.org/issue?@action=redirect&bpo=33209]: End framing at the end of C implementation of pickle.Pickler.dump().

bpo-32861 [https://bugs.python.org/issue?@action=redirect&bpo=32861]: The urllib.robotparser’s __str__ representation now includes wildcard entries and the “Crawl-delay” and “Request-rate” fields. Also removes extra newlines that were being appended to the end of the string. Patch by Michael Lazar.

bpo-23403 [https://bugs.python.org/issue?@action=redirect&bpo=23403]: DEFAULT_PROTOCOL in pickle was bumped to 4. Protocol 4 is described in PEP 3154 [https://peps.python.org/pep-3154/] and available since Python 3.4. It offers better performance and smaller size compared to protocol 3 introduced in Python 3.0.

bpo-20104 [https://bugs.python.org/issue?@action=redirect&bpo=20104]: Improved error handling and fixed a reference leak in os.posix_spawn().

bpo-33106 [https://bugs.python.org/issue?@action=redirect&bpo=33106]: Deleting a key from a read-only dbm database raises module specific error instead of KeyError.

bpo-33175 [https://bugs.python.org/issue?@action=redirect&bpo=33175]: In dataclasses, Field.__set_name__ now looks up the __set_name__ special method on the class, not the instance, of the default value.

bpo-32380 [https://bugs.python.org/issue?@action=redirect&bpo=32380]: Create functools.singledispatchmethod to support generic single dispatch on descriptors and methods.

bpo-33141 [https://bugs.python.org/issue?@action=redirect&bpo=33141]: Have Field objects pass through __set_name__ to their default values, if they have their own __set_name__.

bpo-33096 [https://bugs.python.org/issue?@action=redirect&bpo=33096]: Allow ttk.Treeview.insert to insert iid that has a false boolean value. Note iid=0 and iid=False would be same. Patch by Garvit Khatri.

bpo-32873 [https://bugs.python.org/issue?@action=redirect&bpo=32873]: Treat type variables and special typing forms as immutable by copy and pickle. This fixes several minor issues and inconsistencies, and improves backwards compatibility with Python 3.6.

bpo-33134 [https://bugs.python.org/issue?@action=redirect&bpo=33134]: When computing dataclass’s __hash__, use the lookup table to contain the function which returns the __hash__ value. This is an improvement over looking up a string, and then testing that string to see what to do.

bpo-33127 [https://bugs.python.org/issue?@action=redirect&bpo=33127]: The ssl module now compiles with LibreSSL 2.7.1.

bpo-32505 [https://bugs.python.org/issue?@action=redirect&bpo=32505]: Raise TypeError if a member variable of a dataclass is of type Field, but doesn’t have a type annotation.

bpo-33078 [https://bugs.python.org/issue?@action=redirect&bpo=33078]: Fix the failure on OSX caused by the tests relying on sem_getvalue

bpo-33116 [https://bugs.python.org/issue?@action=redirect&bpo=33116]: Add ‘Field’ to dataclasses.__all__.

bpo-32896 [https://bugs.python.org/issue?@action=redirect&bpo=32896]: Fix an error where subclassing a dataclass with a field that uses a default_factory would generate an incorrect class.

bpo-33100 [https://bugs.python.org/issue?@action=redirect&bpo=33100]: Dataclasses: If a field has a default value that’s a MemberDescriptorType, then it’s from that field being in __slots__, not an actual default value.

bpo-32953 [https://bugs.python.org/issue?@action=redirect&bpo=32953]: If a non-dataclass inherits from a frozen dataclass, allow attributes to be added to the derived class. Only attributes from the frozen dataclass cannot be assigned to. Require all dataclasses in a hierarchy to be either all frozen or all non-frozen.

bpo-33097 [https://bugs.python.org/issue?@action=redirect&bpo=33097]: Raise RuntimeError when executor.submit is called during interpreter shutdown.

bpo-32968 [https://bugs.python.org/issue?@action=redirect&bpo=32968]: Modulo and floor division involving Fraction and float should return float.

bpo-33061 [https://bugs.python.org/issue?@action=redirect&bpo=33061]: Add missing NoReturn to __all__ in typing.py

bpo-33078 [https://bugs.python.org/issue?@action=redirect&bpo=33078]: Fix the size handling in multiprocessing.Queue when a pickling error occurs.

bpo-33064 [https://bugs.python.org/issue?@action=redirect&bpo=33064]: lib2to3 now properly supports trailing commas after *args and **kwargs in function signatures.

bpo-33056 [https://bugs.python.org/issue?@action=redirect&bpo=33056]: FIX properly close leaking fds in concurrent.futures.ProcessPoolExecutor.

bpo-33021 [https://bugs.python.org/issue?@action=redirect&bpo=33021]: Release the GIL during fstat() calls, avoiding hang of all threads when calling mmap.mmap(), os.urandom(), and random.seed(). Patch by Nir Soffer.

bpo-31804 [https://bugs.python.org/issue?@action=redirect&bpo=31804]: Avoid failing in multiprocessing.Process if the standard streams are closed or None at exit.

bpo-33034 [https://bugs.python.org/issue?@action=redirect&bpo=33034]: Providing an explicit error message when casting the port property to anything that is not an integer value using urlparse() and urlsplit(). Patch by Matt Eaton.

bpo-30249 [https://bugs.python.org/issue?@action=redirect&bpo=30249]: Improve struct.unpack_from() exception messages for problems with the buffer size and offset.

bpo-33037 [https://bugs.python.org/issue?@action=redirect&bpo=33037]: Skip sending/receiving data after SSL transport closing.

bpo-27683 [https://bugs.python.org/issue?@action=redirect&bpo=27683]: Fix a regression in ipaddress that result of hosts() is empty when the network is constructed by a tuple containing an integer mask and only 1 bit left for addresses.

bpo-22674 [https://bugs.python.org/issue?@action=redirect&bpo=22674]: Add the strsignal() function in the signal module that returns the system description of the given signal, as returned by strsignal(3).

bpo-32999 [https://bugs.python.org/issue?@action=redirect&bpo=32999]: Fix C implementation of ABC.__subclasscheck__(cls, subclass) crashed when subclass is not a type object.

bpo-33009 [https://bugs.python.org/issue?@action=redirect&bpo=33009]: Fix inspect.signature() for single-parameter partialmethods.

bpo-32969 [https://bugs.python.org/issue?@action=redirect&bpo=32969]: Expose several missing constants in zlib and fix corresponding documentation.

bpo-32056 [https://bugs.python.org/issue?@action=redirect&bpo=32056]: Improved exceptions raised for invalid number of channels and sample width when read an audio file in modules aifc, wave and sunau.

bpo-32970 [https://bugs.python.org/issue?@action=redirect&bpo=32970]: Improved disassembly of the MAKE_FUNCTION instruction.

bpo-32844 [https://bugs.python.org/issue?@action=redirect&bpo=32844]: Fix wrong redirection of a low descriptor (0 or 1) to stderr in subprocess if another low descriptor is closed.

bpo-32960 [https://bugs.python.org/issue?@action=redirect&bpo=32960]: For dataclasses, disallow inheriting frozen from non-frozen classes, and also disallow inheriting non-frozen from frozen classes. This restriction will be relaxed at a future date.

bpo-32713 [https://bugs.python.org/issue?@action=redirect&bpo=32713]: Fixed tarfile.itn handling of out-of-bounds float values. Patch by Joffrey Fuhrer.

bpo-32257 [https://bugs.python.org/issue?@action=redirect&bpo=32257]: The ssl module now contains OP_NO_RENEGOTIATION constant, available with OpenSSL 1.1.0h or 1.1.1.

bpo-32951 [https://bugs.python.org/issue?@action=redirect&bpo=32951]: Direct instantiation of SSLSocket and SSLObject objects is now prohibited. The constructors were never documented, tested, or designed as public constructors. Users were suppose to use ssl.wrap_socket() or SSLContext.

bpo-32929 [https://bugs.python.org/issue?@action=redirect&bpo=32929]: Remove the tri-state parameter “hash”, and add the boolean “unsafe_hash”. If unsafe_hash is True, add a __hash__ function, but if a __hash__ exists, raise TypeError. If unsafe_hash is False, add a __hash__ based on the values of eq= and frozen=. The unsafe_hash=False behavior is the same as the old hash=None behavior. unsafe_hash=False is the default, just as hash=None used to be.

bpo-32947 [https://bugs.python.org/issue?@action=redirect&bpo=32947]: Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for TLSv1.3 for future compatibility with OpenSSL 1.1.1.

bpo-32146 [https://bugs.python.org/issue?@action=redirect&bpo=32146]: Document the interaction between frozen executables and the spawn and forkserver start methods in multiprocessing.

bpo-30622 [https://bugs.python.org/issue?@action=redirect&bpo=30622]: The ssl module now detects missing NPN support in LibreSSL.

bpo-32922 [https://bugs.python.org/issue?@action=redirect&bpo=32922]: dbm.open() now encodes filename with the filesystem encoding rather than default encoding.

bpo-32759 [https://bugs.python.org/issue?@action=redirect&bpo=32759]: Free unused arenas in multiprocessing.heap.

bpo-32859 [https://bugs.python.org/issue?@action=redirect&bpo=32859]: In os.dup2, don’t check every call whether the dup3 syscall exists or not.

bpo-32556 [https://bugs.python.org/issue?@action=redirect&bpo=32556]: nt._getfinalpathname, nt._getvolumepathname and nt._getdiskusage now correctly convert from bytes.

bpo-21060 [https://bugs.python.org/issue?@action=redirect&bpo=21060]: Rewrite confusing message from setup.py upload from “No dist file created in earlier command” to the more helpful “Must create and upload files in one command”.

bpo-32857 [https://bugs.python.org/issue?@action=redirect&bpo=32857]: In tkinter, after_cancel(None) now raises a ValueError instead of canceling the first scheduled function. Patch by Cheryl Sabella.

bpo-32852 [https://bugs.python.org/issue?@action=redirect&bpo=32852]: Make sure sys.argv remains as a list when running trace.

bpo-31333 [https://bugs.python.org/issue?@action=redirect&bpo=31333]: _abc module is added. It is a speedup module with C implementations for various functions and methods in abc. Creating an ABC subclass and calling isinstance or issubclass with an ABC subclass are up to 1.5x faster. In addition, this makes Python start-up up to 10% faster.

Note that the new implementation hides internal registry and caches, previously accessible via private attributes _abc_registry, _abc_cache, and _abc_negative_cache. There are three debugging helper methods that can be used instead _dump_registry, _abc_registry_clear, and _abc_caches_clear.

bpo-32841 [https://bugs.python.org/issue?@action=redirect&bpo=32841]: Fixed asyncio.Condition issue which silently ignored cancellation after notifying and cancelling a conditional lock. Patch by Bar Harel.

bpo-32819 [https://bugs.python.org/issue?@action=redirect&bpo=32819]: ssl.match_hostname() has been simplified and no longer depends on re and ipaddress module for wildcard and IP addresses. Error reporting for invalid wildcards has been improved.

bpo-19675 [https://bugs.python.org/issue?@action=redirect&bpo=19675]: multiprocessing.Pool no longer leaks processes if its initialization fails.

bpo-32394 [https://bugs.python.org/issue?@action=redirect&bpo=32394]: socket: Remove TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older version Windows during run-time.

bpo-31787 [https://bugs.python.org/issue?@action=redirect&bpo=31787]: Fixed refleaks of __init__() methods in various modules. (Contributed by Oren Milman)

bpo-30157 [https://bugs.python.org/issue?@action=redirect&bpo=30157]: Fixed guessing quote and delimiter in csv.Sniffer.sniff() when only the last field is quoted. Patch by Jake Davis.

bpo-30688 [https://bugs.python.org/issue?@action=redirect&bpo=30688]: Added support of \N{name} escapes in regular expressions. Based on patch by Jonathan Eunice.

bpo-32792 [https://bugs.python.org/issue?@action=redirect&bpo=32792]: collections.ChainMap() preserves the order of the underlying mappings.

bpo-32775 [https://bugs.python.org/issue?@action=redirect&bpo=32775]: fnmatch.translate() no longer produces patterns which contain set operations. Sets starting with ‘[’ or containing ‘–’, ‘&&’, ‘~~’ or ‘||’ will be interpreted differently in regular expressions in future versions. Currently they emit warnings. fnmatch.translate() now avoids producing patterns containing such sets by accident.

bpo-32622 [https://bugs.python.org/issue?@action=redirect&bpo=32622]: Implement native fast sendfile for Windows proactor event loop.

bpo-32777 [https://bugs.python.org/issue?@action=redirect&bpo=32777]: Fix a rare but potential pre-exec child process deadlock in subprocess on POSIX systems when marking file descriptors inheritable on exec in the child process. This bug appears to have been introduced in 3.4.

bpo-32647 [https://bugs.python.org/issue?@action=redirect&bpo=32647]: The ctypes module used to depend on indirect linking for dlopen. The shared extension is now explicitly linked against libdl on platforms with dl.

bpo-32749 [https://bugs.python.org/issue?@action=redirect&bpo=32749]: A dbm.dumb database opened with flags ‘r’ is now read-only. dbm.dumb.open() with flags ‘r’ and ‘w’ no longer creates a database if it does not exist.

bpo-32741 [https://bugs.python.org/issue?@action=redirect&bpo=32741]: Implement asyncio.TimerHandle.when() method.

bpo-32691 [https://bugs.python.org/issue?@action=redirect&bpo=32691]: Use mod_spec.parent when running modules with pdb

bpo-32734 [https://bugs.python.org/issue?@action=redirect&bpo=32734]: Fixed asyncio.Lock() safety issue which allowed acquiring and locking the same lock multiple times, without it being free. Patch by Bar Harel.

bpo-32727 [https://bugs.python.org/issue?@action=redirect&bpo=32727]: Do not include name field in SMTP envelope from address. Patch by Stéphane Wirtel

bpo-31453 [https://bugs.python.org/issue?@action=redirect&bpo=31453]: Add TLSVersion constants and SSLContext.maximum_version / minimum_version attributes. The new API wraps OpenSSL 1.1 https://web.archive.org/web/20180309043602/https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html feature.

bpo-24334 [https://bugs.python.org/issue?@action=redirect&bpo=24334]: Internal implementation details of ssl module were cleaned up. The SSLSocket has one less layer of indirection. Owner and session information are now handled by the SSLSocket and SSLObject constructor. Channel binding implementation has been simplified.

bpo-31848 [https://bugs.python.org/issue?@action=redirect&bpo=31848]: Fix the error handling in Aifc_read.initfp() when the SSND chunk is not found. Patch by Zackery Spytz.

bpo-32585 [https://bugs.python.org/issue?@action=redirect&bpo=32585]: Add Ttk spinbox widget to tkinter.ttk. Patch by Alan D Moore.

bpo-32512 [https://bugs.python.org/issue?@action=redirect&bpo=32512]: profile CLI accepts -m module_name as an alternative to script path.

bpo-8525 [https://bugs.python.org/issue?@action=redirect&bpo=8525]: help() on a type now displays builtin subclasses. This is intended primarily to help with notification of more specific exception subclasses.

Patch by Sanyam Khurana.

bpo-31639 [https://bugs.python.org/issue?@action=redirect&bpo=31639]: http.server now exposes a ThreadingHTTPServer class and uses it when the module is run with -m to cope with web browsers pre-opening sockets.

bpo-29877 [https://bugs.python.org/issue?@action=redirect&bpo=29877]: compileall: import ProcessPoolExecutor only when needed, preventing hangs on low resource platforms

bpo-32221 [https://bugs.python.org/issue?@action=redirect&bpo=32221]: Various functions returning tuple containing IPv6 addresses now omit %scope part since the same information is already encoded in scopeid tuple item. Especially this speeds up socket.recvfrom() when it receives multicast packet since useless resolving of network interface name is omitted.

bpo-32147 [https://bugs.python.org/issue?@action=redirect&bpo=32147]: binascii.unhexlify() is now up to 2 times faster. Patch by Sergey Fedoseev.

bpo-30693 [https://bugs.python.org/issue?@action=redirect&bpo=30693]: The TarFile class now recurses directories in a reproducible way.

bpo-30693 [https://bugs.python.org/issue?@action=redirect&bpo=30693]: The ZipFile class now recurses directories in a reproducible way.

bpo-31680 [https://bugs.python.org/issue?@action=redirect&bpo=31680]: Added curses.ncurses_version.

bpo-31908 [https://bugs.python.org/issue?@action=redirect&bpo=31908]: Fix output of cover files for trace module command-line tool. Previously emitted cover files only when --missing option was used. Patch by Michael Selik.

bpo-31608 [https://bugs.python.org/issue?@action=redirect&bpo=31608]: Raise a TypeError instead of crashing if a collections.deque subclass returns a non-deque from __new__. Patch by Oren Milman.

bpo-31425 [https://bugs.python.org/issue?@action=redirect&bpo=31425]: Add support for sockets of the AF_QIPCRTR address family, supported by the Linux kernel. This is used to communicate with services, such as GPS or radio, running on Qualcomm devices. Patch by Bjorn Andersson.

bpo-22005 [https://bugs.python.org/issue?@action=redirect&bpo=22005]: Implemented unpickling instances of datetime, date and time pickled by Python 2. encoding='latin1' should be used for successful decoding.

bpo-27645 [https://bugs.python.org/issue?@action=redirect&bpo=27645]: sqlite3.Connection now exposes a backup method, if the underlying SQLite library is at version 3.6.11 or higher. Patch by Lele Gaifax.

bpo-16865 [https://bugs.python.org/issue?@action=redirect&bpo=16865]: Support arrays >=2GiB in ctypes. Patch by Segev Finer.

bpo-31508 [https://bugs.python.org/issue?@action=redirect&bpo=31508]: Removed support of arguments in tkinter.ttk.Treeview.selection. It was deprecated in 3.6. Use specialized methods like selection_set for changing the selection.

bpo-29456 [https://bugs.python.org/issue?@action=redirect&bpo=29456]: Fix bugs in hangul normalization: u1176, u11a7 and u11c3

Documentation

bpo-21257 [https://bugs.python.org/issue?@action=redirect&bpo=21257]: Document http.client.parse_headers().

bpo-34764 [https://bugs.python.org/issue?@action=redirect&bpo=34764]: Improve example of iter() with 2nd sentinel argument.

bpo-35564 [https://bugs.python.org/issue?@action=redirect&bpo=35564]: Explicitly set master_doc variable in conf.py for compliance with Sphinx 2.0

bpo-35511 [https://bugs.python.org/issue?@action=redirect&bpo=35511]: Specified that profile.Profile class doesn’t not support enable or disable methods. Also, elaborated that Profile object as a context manager is only supported in cProfile module.

bpo-10536 [https://bugs.python.org/issue?@action=redirect&bpo=10536]: Enhance the gettext docs. Patch by Éric Araujo

bpo-35089 [https://bugs.python.org/issue?@action=redirect&bpo=35089]: Remove mention of typing.io and typing.re. Their types should be imported from typing directly.

bpo-35038 [https://bugs.python.org/issue?@action=redirect&bpo=35038]: Fix the documentation about an unexisting f_restricted attribute in the frame object. Patch by Stéphane Wirtel

bpo-35042 [https://bugs.python.org/issue?@action=redirect&bpo=35042]: Replace PEP XYZ by the pep role and allow to use the direct links to the PEPs.

bpo-35044 [https://bugs.python.org/issue?@action=redirect&bpo=35044]: Fix the documentation with the role exc for the appropriated exception. Patch by Stéphane Wirtel

bpo-35035 [https://bugs.python.org/issue?@action=redirect&bpo=35035]: Rename documentation for email.utils to email.utils.rst.

bpo-34967 [https://bugs.python.org/issue?@action=redirect&bpo=34967]: Use app.add_object_type() instead of the deprecated Sphinx function app.description_unit()

bpo-34913 [https://bugs.python.org/issue?@action=redirect&bpo=34913]: Add documentation about the new command line interface of the gzip module.

bpo-32174 [https://bugs.python.org/issue?@action=redirect&bpo=32174]: chm document displays non-ASCII characters properly on some MBCS Windows systems.

bpo-11233 [https://bugs.python.org/issue?@action=redirect&bpo=11233]: Create availability directive for documentation. Original patch by Georg Brandl.

bpo-34790 [https://bugs.python.org/issue?@action=redirect&bpo=34790]: Document how passing coroutines to asyncio.wait() can be confusing.

bpo-34552 [https://bugs.python.org/issue?@action=redirect&bpo=34552]: Make clear that == operator sometimes is equivalent to is. The <, <=, > and >= operators are only defined where they make sense.

bpo-28617 [https://bugs.python.org/issue?@action=redirect&bpo=28617]: Fixed info in the stdtypes docs concerning the types that support membership tests.

bpo-20177 [https://bugs.python.org/issue?@action=redirect&bpo=20177]: Migrate datetime.date.fromtimestamp to Argument Clinic. Patch by Tim Hoffmann.

bpo-34065 [https://bugs.python.org/issue?@action=redirect&bpo=34065]: Fix wrongly written basicConfig documentation markup syntax

bpo-33460 [https://bugs.python.org/issue?@action=redirect&bpo=33460]: replaced ellipsis with correct error codes in tutorial chapter 3.

bpo-33847 [https://bugs.python.org/issue?@action=redirect&bpo=33847]: Add ‘@’ operator entry to index.

bpo-33409 [https://bugs.python.org/issue?@action=redirect&bpo=33409]: Clarified the relationship between PEP 538 [https://peps.python.org/pep-0538/]’s PYTHONCOERCECLOCALE and PEP 540’s PYTHONUTF8 mode.

bpo-33197 [https://bugs.python.org/issue?@action=redirect&bpo=33197]: Add versionadded tag to the documentation of ParameterKind.description

bpo-17045 [https://bugs.python.org/issue?@action=redirect&bpo=17045]: Improve the C-API doc for PyTypeObject. This includes adding several quick-reference tables and a lot of missing slot/typedef entries. The existing entries were also cleaned up with a slightly more consistent format.

bpo-33736 [https://bugs.python.org/issue?@action=redirect&bpo=33736]: Improve the documentation of asyncio.open_connection(), asyncio.start_server() and their UNIX socket counterparts.

bpo-23859 [https://bugs.python.org/issue?@action=redirect&bpo=23859]: Document that asyncio.wait() does not cancel its futures on timeout.

bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436]: Document PEP 567 [https://peps.python.org/pep-0567/] changes to asyncio.

bpo-33604 [https://bugs.python.org/issue?@action=redirect&bpo=33604]: Update HMAC md5 default to a DeprecationWarning, bump removal to 3.8.

bpo-33594 [https://bugs.python.org/issue?@action=redirect&bpo=33594]: Document getargspec, from_function and from_builtin as deprecated in their respective docstring, and include version since deprecation in DeprecationWarning message.

bpo-33503 [https://bugs.python.org/issue?@action=redirect&bpo=33503]: Fix broken pypi link

bpo-33421 [https://bugs.python.org/issue?@action=redirect&bpo=33421]: Add missing documentation for typing.AsyncContextManager.

bpo-33487 [https://bugs.python.org/issue?@action=redirect&bpo=33487]: BZ2file now emit a DeprecationWarning when buffering=None is passed, the deprecation message and documentation also now explicitly state it is deprecated since 3.0.

bpo-33378 [https://bugs.python.org/issue?@action=redirect&bpo=33378]: Add Korean language switcher for https://docs.python.org/3/

bpo-33276 [https://bugs.python.org/issue?@action=redirect&bpo=33276]: Clarify that the __path__ attribute on modules cannot be just any value.

bpo-33201 [https://bugs.python.org/issue?@action=redirect&bpo=33201]: Modernize documentation for writing C extension types.

bpo-33195 [https://bugs.python.org/issue?@action=redirect&bpo=33195]: Deprecate Py_UNICODE usage in c-api/arg document. Py_UNICODE related APIs are deprecated since Python 3.3, but it is missed in the document.

bpo-33126 [https://bugs.python.org/issue?@action=redirect&bpo=33126]: Document PyBuffer_ToContiguous().

bpo-27212 [https://bugs.python.org/issue?@action=redirect&bpo=27212]: Modify documentation for the islice() recipe to consume initial values up to the start index.

bpo-28247 [https://bugs.python.org/issue?@action=redirect&bpo=28247]: Update zipapp documentation to describe how to make standalone applications.

bpo-18802 [https://bugs.python.org/issue?@action=redirect&bpo=18802]: Documentation changes for ipaddress. Patch by Jon Foster and Berker Peksag.

bpo-27428 [https://bugs.python.org/issue?@action=redirect&bpo=27428]: Update documentation to clarify that WindowsRegistryFinder implements MetaPathFinder. (Patch by Himanshu Lakhara)

bpo-28124 [https://bugs.python.org/issue?@action=redirect&bpo=28124]: The ssl module function ssl.wrap_socket() has been de-emphasized and deprecated in favor of the more secure and efficient SSLContext.wrap_socket() method.

bpo-17232 [https://bugs.python.org/issue?@action=redirect&bpo=17232]: Clarify docs for -O and -OO. Patch by Terry Reedy.

bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436]: Add documentation for the contextvars module (PEP 567).

bpo-32800 [https://bugs.python.org/issue?@action=redirect&bpo=32800]: Update link to w3c doc for xml default namespaces.

bpo-11015 [https://bugs.python.org/issue?@action=redirect&bpo=11015]: Update test.support documentation.

bpo-32613 [https://bugs.python.org/issue?@action=redirect&bpo=32613]: Update the faq/windows.html to use the py command from PEP 397 instead of python.

bpo-8722 [https://bugs.python.org/issue?@action=redirect&bpo=8722]: Document __getattr__() behavior when property get() method raises AttributeError.

bpo-32614 [https://bugs.python.org/issue?@action=redirect&bpo=32614]: Modify RE examples in documentation to use raw strings to prevent DeprecationWarning and add text to REGEX HOWTO to highlight the deprecation.

bpo-20709 [https://bugs.python.org/issue?@action=redirect&bpo=20709]: Remove the paragraph where we explain that os.utime() does not support a directory as path under Windows. Patch by Jan-Philip Gehrcke

bpo-32722 [https://bugs.python.org/issue?@action=redirect&bpo=32722]: Remove the bad example in the tutorial of the Generator Expression. Patch by Stéphane Wirtel

bpo-31972 [https://bugs.python.org/issue?@action=redirect&bpo=31972]: Improve docstrings for pathlib.PurePath subclasses.

bpo-30607 [https://bugs.python.org/issue?@action=redirect&bpo=30607]: Use the externalized python-docs-theme package when building the documentation.

bpo-8243 [https://bugs.python.org/issue?@action=redirect&bpo=8243]: Add a note about curses.addch and curses.addstr exception behavior when writing outside a window, or pad.

bpo-32337 [https://bugs.python.org/issue?@action=redirect&bpo=32337]: Update documentation related with dict order.

bpo-25041 [https://bugs.python.org/issue?@action=redirect&bpo=25041]: Document AF_PACKET in the socket module.

bpo-31432 [https://bugs.python.org/issue?@action=redirect&bpo=31432]: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

Tests

bpo-35772 [https://bugs.python.org/issue?@action=redirect&bpo=35772]: Fix sparse file tests of test_tarfile on ppc64 with the tmpfs filesystem. Fix the function testing if the filesystem supports sparse files: create a file which contains data and “holes”, instead of creating a file which contains no data. tmpfs effective block size is a page size (tmpfs lives in the page cache). RHEL uses 64 KiB pages on aarch64, ppc64, ppc64le, only s390x and x86_64 use 4 KiB pages, whereas the test punch holes of 4 KiB.

bpo-35045 [https://bugs.python.org/issue?@action=redirect&bpo=35045]: Make ssl tests less strict and also accept TLSv1 as system default. The changes unbreaks test_min_max_version on Fedora 29.

bpo-32710 [https://bugs.python.org/issue?@action=redirect&bpo=32710]: test_asyncio/test_sendfile.py now resets the event loop policy using tearDownModule() as done in other tests, to prevent a warning when running tests on Windows.

bpo-33717 [https://bugs.python.org/issue?@action=redirect&bpo=33717]: test.pythoninfo now logs information of all clocks, not only time.time() and time.perf_counter().

bpo-35488 [https://bugs.python.org/issue?@action=redirect&bpo=35488]: Add a test to pathlib’s Path.match() to verify it does not support glob-style ** recursive pattern matching.

bpo-31731 [https://bugs.python.org/issue?@action=redirect&bpo=31731]: Fix a race condition in check_interrupted_write() of test_io: create directly the thread with SIGALRM signal blocked, rather than blocking the signal later from the thread. Previously, it was possible that the thread gets the signal before the signal is blocked.

bpo-35424 [https://bugs.python.org/issue?@action=redirect&bpo=35424]: Fix test_multiprocessing_main_handling: use multiprocessing.Pool with a context manager and then explicitly join the pool.

bpo-35519 [https://bugs.python.org/issue?@action=redirect&bpo=35519]: Rename test.bisect module to test.bisect_cmd to avoid conflict with bisect module when running directly a test like ./python Lib/test/test_xmlrpc.py.

bpo-35513 [https://bugs.python.org/issue?@action=redirect&bpo=35513]: Replace time.time() with time.monotonic() in tests to measure time delta.

bpo-34279 [https://bugs.python.org/issue?@action=redirect&bpo=34279]: test.support.run_unittest() no longer raise TestDidNotRun if the test result contains skipped tests. The exception is now only raised if no test have been run and no test have been skipped.

bpo-35412 [https://bugs.python.org/issue?@action=redirect&bpo=35412]: Add testcase to test_future4: check unicode literal.

bpo-26704 [https://bugs.python.org/issue?@action=redirect&bpo=26704]: Added test demonstrating double-patching of an instance method. Patch by Anthony Sottile.

bpo-33725 [https://bugs.python.org/issue?@action=redirect&bpo=33725]: test_multiprocessing_fork may crash on recent versions of macOS. Until the issue is resolved, skip the test on macOS.

bpo-35352 [https://bugs.python.org/issue?@action=redirect&bpo=35352]: Modify test_asyncio to use the certificate set from the test directory.

bpo-35317 [https://bugs.python.org/issue?@action=redirect&bpo=35317]: Fix mktime() overflow error in test_email: run test_localtime_daylight_true_dst_true() and test_localtime_daylight_false_dst_true() with a specific timezone.

bpo-21263 [https://bugs.python.org/issue?@action=redirect&bpo=21263]: After several reports that test_gdb does not work properly on macOS and since gdb is not shipped by default anymore, test_gdb is now skipped on macOS when LLVM Clang has been used to compile Python. Patch by Lysandros Nikolaou

bpo-34279 [https://bugs.python.org/issue?@action=redirect&bpo=34279]: regrtest issue a warning when no tests have been executed in a particular test file. Also, a new final result state is issued if no test have been executed across all test files. Patch by Pablo Galindo.

bpo-34962 [https://bugs.python.org/issue?@action=redirect&bpo=34962]: make docstest in Doc now passes., and is enforced in CI

bpo-23596 [https://bugs.python.org/issue?@action=redirect&bpo=23596]: Use argparse for the command line of the gzip module. Patch by Antony Lee

bpo-34537 [https://bugs.python.org/issue?@action=redirect&bpo=34537]: Fix test_gdb.test_strings() when LC_ALL=C and GDB was compiled with Python 3.6 or earlier.

bpo-34587 [https://bugs.python.org/issue?@action=redirect&bpo=34587]: test_socket: Remove RDSTest.testCongestion(). The test tries to fill the receiver’s socket buffer and expects an error. But the RDS protocol doesn’t require that. Moreover, the Linux implementation of RDS expects that the producer of the messages reduces its rate, it’s not the role of the receiver to trigger an error. The test fails on Fedora 28 by design, so just remove it.

bpo-34661 [https://bugs.python.org/issue?@action=redirect&bpo=34661]: Fix test_shutil if unzip doesn’t support -t.

bpo-34200 [https://bugs.python.org/issue?@action=redirect&bpo=34200]: Fixed non-deterministic flakiness of test_pkg by not using the scary test.support.module_cleanup() logic to save and restore sys.modules contents between test cases.

bpo-34569 [https://bugs.python.org/issue?@action=redirect&bpo=34569]: The experimental PEP 554 data channels now correctly pass negative PyLong objects between subinterpreters on 32-bit systems. Patch by Michael Felt.

bpo-34594 [https://bugs.python.org/issue?@action=redirect&bpo=34594]: Fix usage of hardcoded errno values in the tests.

bpo-34579 [https://bugs.python.org/issue?@action=redirect&bpo=34579]: Fix test_embed for AIX Patch by Michael Felt

bpo-34542 [https://bugs.python.org/issue?@action=redirect&bpo=34542]: Use 3072 RSA keys and SHA-256 signature for test certs and keys.

bpo-11193 [https://bugs.python.org/issue?@action=redirect&bpo=11193]: Remove special condition for AIX in test_subprocess.test_undecodable_env

bpo-34347 [https://bugs.python.org/issue?@action=redirect&bpo=34347]: Fix test_utf8_mode.test_cmd_line for AIX

bpo-34490 [https://bugs.python.org/issue?@action=redirect&bpo=34490]: On AIX with AF_UNIX family sockets getsockname() does not provide ‘sockname’, so skip calls to transport.get_extra_info(‘sockname’)

bpo-34391 [https://bugs.python.org/issue?@action=redirect&bpo=34391]: Fix ftplib test for TLS 1.3 by reading from data socket.

bpo-11192 [https://bugs.python.org/issue?@action=redirect&bpo=11192]: Fix test_socket on AIX 6.1 and later IPv6 zone id supports only supported by inet_pton6_zone(). Switch to runtime-based platform.system() to establish current platform rather than build-time based sys.platform()

bpo-34399 [https://bugs.python.org/issue?@action=redirect&bpo=34399]: Update all RSA keys and DH params to use at least 2048 bits.

bpo-34373 [https://bugs.python.org/issue?@action=redirect&bpo=34373]: Fix test_mktime and test_pthread_getcpuclickid tests for AIX Add range checking for _PyTime_localtime for AIX Patch by Michael Felt

bpo-11191 [https://bugs.python.org/issue?@action=redirect&bpo=11191]: Skip the distutils test ‘test_search_cpp’ when using XLC as compiler patch by aixtools (Michael Felt)

Improved an error message when mock assert_has_calls fails.

bpo-33746 [https://bugs.python.org/issue?@action=redirect&bpo=33746]: Fix test_unittest when run in verbose mode.

bpo-33901 [https://bugs.python.org/issue?@action=redirect&bpo=33901]: Fix test_dbm_gnu on macOS with gdbm 1.15: add a larger value to make sure that the file size changes.

bpo-33873 [https://bugs.python.org/issue?@action=redirect&bpo=33873]: Fix a bug in regrtest that caused an extra test to run if –huntrleaks/-R was used. Exit with error in case that invalid parameters are specified to –huntrleaks/-R (at least one warmup run and one repetition must be used).

bpo-33562 [https://bugs.python.org/issue?@action=redirect&bpo=33562]: Check that a global asyncio event loop policy is not left behind by any tests.

bpo-33655 [https://bugs.python.org/issue?@action=redirect&bpo=33655]: Ignore test_posix_fallocate failures on BSD platforms that might be due to running on ZFS.

bpo-32962 [https://bugs.python.org/issue?@action=redirect&bpo=32962]: Fixed test_gdb when Python is compiled with flags -mcet -fcf-protection -O0.

bpo-33358 [https://bugs.python.org/issue?@action=redirect&bpo=33358]: Fix test_embed.test_pre_initialization_sys_options() when the interpreter is built with --enable-shared.

bpo-32872 [https://bugs.python.org/issue?@action=redirect&bpo=32872]: Avoid regrtest compatibility issue with namespace packages.

bpo-32517 [https://bugs.python.org/issue?@action=redirect&bpo=32517]: Fix failing test_asyncio on macOS 10.12.2+ due to transport of KqueueSelector loop was not being closed.

bpo-32663 [https://bugs.python.org/issue?@action=redirect&bpo=32663]: Making sure the SMTPUTF8SimTests class of tests gets run in test_smtplib.py.

bpo-27643 [https://bugs.python.org/issue?@action=redirect&bpo=27643]: Test_C test case needs “signed short” bitfields, but the IBM XLC compiler (on AIX) does not support this Skip the code and test when AIX and XLC are used

Applicable to Python2-2.7 and later

bpo-19417 [https://bugs.python.org/issue?@action=redirect&bpo=19417]: Add test_bdb.py.

bpo-31809 [https://bugs.python.org/issue?@action=redirect&bpo=31809]: Add tests to verify connection with secp ECDH curves.

Build

bpo-34691 [https://bugs.python.org/issue?@action=redirect&bpo=34691]: The _contextvars module is now built into the core Python library on Windows.

bpo-35683 [https://bugs.python.org/issue?@action=redirect&bpo=35683]: Improved Azure Pipelines build steps and now verifying layouts correctly

bpo-35642 [https://bugs.python.org/issue?@action=redirect&bpo=35642]: Remove asynciomodule.c from pythoncore.vcxproj

bpo-35550 [https://bugs.python.org/issue?@action=redirect&bpo=35550]: Fix incorrect Solaris #ifdef checks to look for __sun && __SVR4 instead of sun when compiling.

bpo-35499 [https://bugs.python.org/issue?@action=redirect&bpo=35499]: make profile-opt no longer replaces CFLAGS_NODIST with CFLAGS. It now adds profile-guided optimization (PGO) flags to CFLAGS_NODIST: existing CFLAGS_NODIST flags are kept.

bpo-35257 [https://bugs.python.org/issue?@action=redirect&bpo=35257]: Avoid leaking the linker flags from Link Time Optimizations (LTO) into distutils when compiling C extensions.

bpo-35351 [https://bugs.python.org/issue?@action=redirect&bpo=35351]: When building Python with clang and LTO, LTO flags are no longer passed into CFLAGS to build third-party C extensions through distutils.

bpo-35139 [https://bugs.python.org/issue?@action=redirect&bpo=35139]: Fix a compiler error when statically linking pyexpat in Modules/Setup.

bpo-35059 [https://bugs.python.org/issue?@action=redirect&bpo=35059]: PCbuild: Set InlineFunctionExpansion to OnlyExplicitInline (“/Ob1” option) in pyproject.props in Debug mode to expand functions marked as inline. This change should make Python compiled in Debug mode a little bit faster on Windows.

bpo-35011 [https://bugs.python.org/issue?@action=redirect&bpo=35011]: Restores the use of pyexpatns.h to isolate our embedded copy of the expat C library so that its symbols do not conflict at link or dynamic loading time with an embedding application or other extension modules with their own version of libexpat.

bpo-28015 [https://bugs.python.org/issue?@action=redirect&bpo=28015]: Have –with-lto works correctly with clang.

bpo-34765 [https://bugs.python.org/issue?@action=redirect&bpo=34765]: Update the outdated install-sh file to the latest revision from automake v1.16.1

bpo-34585 [https://bugs.python.org/issue?@action=redirect&bpo=34585]: Check for floating-point byte order in configure.ac using compilation tests instead of executing code, so that these checks work in cross-compiled builds.

bpo-34710 [https://bugs.python.org/issue?@action=redirect&bpo=34710]: Fixed SSL module build with OpenSSL & pedantic CFLAGS.

bpo-34582 [https://bugs.python.org/issue?@action=redirect&bpo=34582]: Add JUnit XML output for regression tests and update Azure DevOps builds.

bpo-34081 [https://bugs.python.org/issue?@action=redirect&bpo=34081]: Make Sphinx warnings as errors in the Docs Makefile.

bpo-34555 [https://bugs.python.org/issue?@action=redirect&bpo=34555]: Fix for case where it was not possible to have both HAVE_LINUX_VM_SOCKETS_H and HAVE_SOCKADDR_ALG be undefined.

bpo-33015 [https://bugs.python.org/issue?@action=redirect&bpo=33015]: Fix an undefined behaviour in the pthread implementation of PyThread_start_new_thread(): add a function wrapper to always return NULL.

bpo-34245 [https://bugs.python.org/issue?@action=redirect&bpo=34245]: The Python shared library is now installed with write permission (mode 0755), which is the standard way of installing such libraries.

bpo-34121 [https://bugs.python.org/issue?@action=redirect&bpo=34121]: Fix detection of C11 atomic support on clang.

bpo-32430 [https://bugs.python.org/issue?@action=redirect&bpo=32430]: Rename Modules/Setup.dist to Modules/Setup, and remove the necessity to copy the former manually to the latter when updating the local source tree.

bpo-30345 [https://bugs.python.org/issue?@action=redirect&bpo=30345]: Add -g to LDFLAGS when compiling with LTO to get debug symbols.

bpo-5755 [https://bugs.python.org/issue?@action=redirect&bpo=5755]: Move -Wstrict-prototypes option to CFLAGS_NODIST from OPT. This option emitted annoying warnings when building extension modules written in C++.

bpo-33614 [https://bugs.python.org/issue?@action=redirect&bpo=33614]: Ensures module definition files for the stable ABI on Windows are correctly regenerated.

bpo-33648 [https://bugs.python.org/issue?@action=redirect&bpo=33648]: The –with-c-locale-warning configuration flag has been removed. It has had no effect for about a year.

bpo-33522 [https://bugs.python.org/issue?@action=redirect&bpo=33522]: Enable CI builds on Visual Studio Team Services at https://python.visualstudio.com/cpython

bpo-33512 [https://bugs.python.org/issue?@action=redirect&bpo=33512]: configure’s check for “long double” has been simplified

bpo-33483 [https://bugs.python.org/issue?@action=redirect&bpo=33483]: C compiler is now correctly detected from the standard environment variables. –without-gcc and –with-icc options have been removed.

bpo-33394 [https://bugs.python.org/issue?@action=redirect&bpo=33394]: Enable the verbose build for extension modules, when GNU make is passed macros on the command line.

bpo-33393 [https://bugs.python.org/issue?@action=redirect&bpo=33393]: Update config.guess and config.sub files.

bpo-33377 [https://bugs.python.org/issue?@action=redirect&bpo=33377]: Add new triplets for mips r6 and riscv variants (used in extension suffixes).

bpo-32232 [https://bugs.python.org/issue?@action=redirect&bpo=32232]: By default, modules configured in Modules/Setup are no longer built with -DPy_BUILD_CORE. Instead, modules that specifically need that preprocessor definition include it in their individual entries.

bpo-33182 [https://bugs.python.org/issue?@action=redirect&bpo=33182]: The embedding tests can once again be built with clang 6.0

bpo-33163 [https://bugs.python.org/issue?@action=redirect&bpo=33163]: Upgrade pip to 9.0.3 and setuptools to v39.0.1.

bpo-33012 [https://bugs.python.org/issue?@action=redirect&bpo=33012]: gcc 8 has added a new warning heuristic to detect invalid function casts and a stock python build seems to hit that warning quite often. The most common is the cast of a METH_NOARGS function (that uses just one argument) to a PyCFunction. Fix this by adding a dummy argument to all functions that implement METH_NOARGS.

bpo-32898 [https://bugs.python.org/issue?@action=redirect&bpo=32898]: Fix the python debug build when using COUNT_ALLOCS.

bpo-29442 [https://bugs.python.org/issue?@action=redirect&bpo=29442]: Replace optparse with argparse in setup.py

Windows

bpo-35890 [https://bugs.python.org/issue?@action=redirect&bpo=35890]: Fix API calling consistency of GetVersionEx and wcstok.

bpo-32560 [https://bugs.python.org/issue?@action=redirect&bpo=32560]: The py launcher now forwards its STARTUPINFO structure to child processes.

bpo-35854 [https://bugs.python.org/issue?@action=redirect&bpo=35854]: Fix EnvBuilder and –symlinks in venv on Windows

bpo-35811 [https://bugs.python.org/issue?@action=redirect&bpo=35811]: Avoid propagating venv settings when launching via py.exe

bpo-35797 [https://bugs.python.org/issue?@action=redirect&bpo=35797]: Fix default executable used by the multiprocessing module

bpo-35758 [https://bugs.python.org/issue?@action=redirect&bpo=35758]: Allow building on ARM with MSVC.

bpo-29734 [https://bugs.python.org/issue?@action=redirect&bpo=29734]: Fix handle leaks in os.stat on Windows.

bpo-35596 [https://bugs.python.org/issue?@action=redirect&bpo=35596]: Use unchecked PYCs for the embeddable distro to avoid zipimport restrictions.

bpo-35596 [https://bugs.python.org/issue?@action=redirect&bpo=35596]: Fix vcruntime140.dll being added to embeddable distro multiple times.

bpo-35402 [https://bugs.python.org/issue?@action=redirect&bpo=35402]: Update Windows build to use Tcl and Tk 8.6.9

bpo-35401 [https://bugs.python.org/issue?@action=redirect&bpo=35401]: Updates Windows build to OpenSSL 1.1.0j

bpo-34977 [https://bugs.python.org/issue?@action=redirect&bpo=34977]: venv on Windows will now use a python.exe redirector rather than copying the actual binaries from the base environment.

bpo-34977 [https://bugs.python.org/issue?@action=redirect&bpo=34977]: Adds support for building a Windows App Store package

bpo-35067 [https://bugs.python.org/issue?@action=redirect&bpo=35067]: Remove _distutils_findvs module and use vswhere.exe instead.

bpo-32557 [https://bugs.python.org/issue?@action=redirect&bpo=32557]: Allow shutil.disk_usage to take a file path on Windows

bpo-34770 [https://bugs.python.org/issue?@action=redirect&bpo=34770]: Fix a possible null pointer dereference in pyshellext.cpp.

bpo-34603 [https://bugs.python.org/issue?@action=redirect&bpo=34603]: Fix returning structs from functions produced by MSVC

bpo-34581 [https://bugs.python.org/issue?@action=redirect&bpo=34581]: Guard MSVC-specific code in socketmodule.c with #ifdef _MSC_VER.

bpo-34532 [https://bugs.python.org/issue?@action=redirect&bpo=34532]: Fixes exit code of list version arguments for py.exe.

bpo-34062 [https://bugs.python.org/issue?@action=redirect&bpo=34062]: Fixed the ‘–list’ and ‘–list-paths’ arguments for the py.exe launcher

bpo-34225 [https://bugs.python.org/issue?@action=redirect&bpo=34225]: Ensure INCLUDE and LIB directories do not end with a backslash.

bpo-34011 [https://bugs.python.org/issue?@action=redirect&bpo=34011]: A suite of code has been changed which copied across DLLs and init.tcl from the running Python location into a venv being created. These copies are needed only when running from a Python source build, and the copying code is now only run when that is the case, rather than whenever a venv is created.

bpo-34006 [https://bugs.python.org/issue?@action=redirect&bpo=34006]: Revert line length limit for Windows help docs. The line-length limit is not needed because the pages appear in a separate app rather than on a browser tab. It can also interact badly with the DPI setting.

bpo-31546 [https://bugs.python.org/issue?@action=redirect&bpo=31546]: Restore running PyOS_InputHook while waiting for user input at the prompt. The restores integration of interactive GUI windows (such as Matplotlib figures) with the prompt on Windows.

bpo-30237 [https://bugs.python.org/issue?@action=redirect&bpo=30237]: Output error when ReadConsole is canceled by CancelSynchronousIo instead of crashing.

bpo-33895 [https://bugs.python.org/issue?@action=redirect&bpo=33895]: GIL is released while calling functions that acquire Windows loader lock.

bpo-33720 [https://bugs.python.org/issue?@action=redirect&bpo=33720]: Reduces maximum marshal recursion depth on release builds.

bpo-29097 [https://bugs.python.org/issue?@action=redirect&bpo=29097]: Fix bug where datetime.fromtimestamp() erroneously throws an OSError on Windows for values between 0 and 86400. Patch by Ammar Askar.

bpo-33316 [https://bugs.python.org/issue?@action=redirect&bpo=33316]: PyThread_release_lock always fails

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update Windows installer to use OpenSSL 1.1.0h.

bpo-32890 [https://bugs.python.org/issue?@action=redirect&bpo=32890]: Fix usage of GetLastError() instead of errno in os.execve() and os.truncate().

bpo-33016 [https://bugs.python.org/issue?@action=redirect&bpo=33016]: Fix potential use of uninitialized memory in nt._getfinalpathname

bpo-32903 [https://bugs.python.org/issue?@action=redirect&bpo=32903]: Fix a memory leak in os.chdir() on Windows if the current directory is set to a UNC path.

bpo-32901 [https://bugs.python.org/issue?@action=redirect&bpo=32901]: Update Tcl and Tk versions to 8.6.8

bpo-31966 [https://bugs.python.org/issue?@action=redirect&bpo=31966]: Fixed WindowsConsoleIO.write() for writing empty data.

bpo-32409 [https://bugs.python.org/issue?@action=redirect&bpo=32409]: Ensures activate.bat can handle Unicode contents.

bpo-32457 [https://bugs.python.org/issue?@action=redirect&bpo=32457]: Improves handling of denormalized executable path when launching Python.

bpo-32370 [https://bugs.python.org/issue?@action=redirect&bpo=32370]: Use the correct encoding for ipconfig output in the uuid module. Patch by Segev Finer.

bpo-29248 [https://bugs.python.org/issue?@action=redirect&bpo=29248]: Fix os.readlink() on Windows, which was mistakenly treating the PrintNameOffset field of the reparse data buffer as a number of characters instead of bytes. Patch by Craig Holmquist and SSE4.

bpo-1104 [https://bugs.python.org/issue?@action=redirect&bpo=1104]: Correctly handle string length in msilib.SummaryInfo.GetProperty() to prevent it from truncating the last character.

macOS

bpo-35401 [https://bugs.python.org/issue?@action=redirect&bpo=35401]: Update macOS installer to use OpenSSL 1.1.0j.

bpo-35025 [https://bugs.python.org/issue?@action=redirect&bpo=35025]: Properly guard the use of the CLOCK_GETTIME et al. macros in timemodule on macOS.

bpo-24658 [https://bugs.python.org/issue?@action=redirect&bpo=24658]: On macOS, fix reading from and writing into a file with a size larger than 2 GiB.

bpo-34405 [https://bugs.python.org/issue?@action=redirect&bpo=34405]: Update to OpenSSL 1.1.0i for macOS installer builds.

bpo-33635 [https://bugs.python.org/issue?@action=redirect&bpo=33635]: In macOS stat on some file descriptors (/dev/fd/3 f.e) will result in bad file descriptor OSError. Guard against this exception was added in is_dir, is_file and similar methods. DirEntry.is_dir can also throw this exception so _RecursiveWildcardSelector._iterate_directories was also extended with the same error ignoring pattern.

bpo-13631 [https://bugs.python.org/issue?@action=redirect&bpo=13631]: The .editrc file in user’s home directory is now processed correctly during the readline initialization through editline emulation on macOS.

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update macOS installer build to use OpenSSL 1.1.0h.

bpo-32726 [https://bugs.python.org/issue?@action=redirect&bpo=32726]: Build and link with private copy of Tcl/Tk 8.6 for the macOS 10.6+ installer. The 10.9+ installer variant already does this. This means that the Python 3.7 provided by the python.org macOS installers no longer need or use any external versions of Tcl/Tk, either system-provided or user-installed, such as ActiveTcl.

bpo-32901 [https://bugs.python.org/issue?@action=redirect&bpo=32901]: Update macOS 10.9+ installer to Tcl/Tk 8.6.8.

bpo-31903 [https://bugs.python.org/issue?@action=redirect&bpo=31903]: In _scproxy, drop the GIL when calling into SystemConfiguration to avoid deadlocks.

IDLE

bpo-35770 [https://bugs.python.org/issue?@action=redirect&bpo=35770]: IDLE macosx deletes Options => Configure IDLE. It previously deleted Window => Zoom Height by mistake. (Zoom Height is now on the Options menu). On Mac, the settings dialog is accessed via Preferences on the IDLE menu.

bpo-35769 [https://bugs.python.org/issue?@action=redirect&bpo=35769]: Change IDLE’s new file name from ‘Untitled’ to ‘untitled’

bpo-35660 [https://bugs.python.org/issue?@action=redirect&bpo=35660]: Fix imports in idlelib.window.

bpo-35641 [https://bugs.python.org/issue?@action=redirect&bpo=35641]: Proper format calltip when the function has no docstring.

bpo-33987 [https://bugs.python.org/issue?@action=redirect&bpo=33987]: Use ttk Frame for ttk widgets.

bpo-34055 [https://bugs.python.org/issue?@action=redirect&bpo=34055]: Fix erroneous ‘smart’ indents and newlines in IDLE Shell.

bpo-35591 [https://bugs.python.org/issue?@action=redirect&bpo=35591]: Find Selection now works when selection not found.

bpo-35196 [https://bugs.python.org/issue?@action=redirect&bpo=35196]: Speed up squeezer line counting.

bpo-35598 [https://bugs.python.org/issue?@action=redirect&bpo=35598]: Update config_key: use PEP 8 names and ttk widgets, make some objects global, and add tests.

bpo-28097 [https://bugs.python.org/issue?@action=redirect&bpo=28097]: Add Previous/Next History entries to Shell menu.

bpo-35208 [https://bugs.python.org/issue?@action=redirect&bpo=35208]: Squeezer now properly counts wrapped lines before newlines.

bpo-35555 [https://bugs.python.org/issue?@action=redirect&bpo=35555]: Gray out Code Context menu entry when it’s not applicable.

bpo-35521 [https://bugs.python.org/issue?@action=redirect&bpo=35521]: Document the IDLE editor code context feature. Add some internal references within the IDLE doc.

bpo-22703 [https://bugs.python.org/issue?@action=redirect&bpo=22703]: The Code Context menu label now toggles between Show/Hide Code Context. The Zoom Height menu now toggles between Zoom/Restore Height. Zoom Height has moved from the Window menu to the Options menu.

bpo-35213 [https://bugs.python.org/issue?@action=redirect&bpo=35213]: Where appropriate, use ‘macOS’ in idlelib.

bpo-34864 [https://bugs.python.org/issue?@action=redirect&bpo=34864]: On macOS, warn if the system preference “Prefer tabs when opening documents” is set to “Always”.

bpo-34864 [https://bugs.python.org/issue?@action=redirect&bpo=34864]: Document two IDLE on MacOS issues. The System Preferences Dock “prefer tabs always” setting disables some IDLE features. Menus are a bit different than as described for Windows and Linux.

bpo-35202 [https://bugs.python.org/issue?@action=redirect&bpo=35202]: Remove unused imports from lib/idlelib

bpo-33000 [https://bugs.python.org/issue?@action=redirect&bpo=33000]: Document that IDLE’s shell has no line limit. A program that runs indefinitely can overfill memory.

bpo-23220 [https://bugs.python.org/issue?@action=redirect&bpo=23220]: Explain how IDLE’s Shell displays output.

bpo-35099 [https://bugs.python.org/issue?@action=redirect&bpo=35099]: Improve the doc about IDLE running user code. The section is renamed from “IDLE – console differences” is renamed “Running user code”. It mostly covers the implications of using custom sys.stdxxx objects.

bpo-35097 [https://bugs.python.org/issue?@action=redirect&bpo=35097]: Add IDLE doc subsection explaining editor windows. Topics include opening, title and status bar, .py* extension, and running.

bpo-35093 [https://bugs.python.org/issue?@action=redirect&bpo=35093]: Document the IDLE document viewer in the IDLE doc. Add a paragraph in “Help and preferences”, “Help sources” subsection.

bpo-35088 [https://bugs.python.org/issue?@action=redirect&bpo=35088]: Update idlelib.help.copy_string docstring. We now use git and backporting instead of hg and forward merging.

bpo-35087 [https://bugs.python.org/issue?@action=redirect&bpo=35087]: Update idlelib help files for the current doc build. The main change is the elimination of chapter-section numbers.

bpo-34548 [https://bugs.python.org/issue?@action=redirect&bpo=34548]: Use configured color theme for read-only text views.

bpo-1529353 [https://bugs.python.org/issue?@action=redirect&bpo=1529353]: Enable “squeezing” of long outputs in the shell, to avoid performance degradation and to clean up the history without losing it. Squeezed outputs may be copied, viewed in a separate window, and “unsqueezed”.

bpo-34047 [https://bugs.python.org/issue?@action=redirect&bpo=34047]: Fixed mousewheel scrolling direction on macOS.

bpo-34275 [https://bugs.python.org/issue?@action=redirect&bpo=34275]: Make IDLE calltips always visible on Mac. Some MacOS-tk combinations need .update_idletasks(). Patch by Kevin Walzer.

bpo-34120 [https://bugs.python.org/issue?@action=redirect&bpo=34120]: Fix unresponsiveness after closing certain windows and dialogs.

bpo-33975 [https://bugs.python.org/issue?@action=redirect&bpo=33975]: Avoid small type when running htests. Since part of the purpose of human-viewed tests is to determine that widgets look right, it is important that they look the same for testing as when running IDLE.

bpo-33905 [https://bugs.python.org/issue?@action=redirect&bpo=33905]: Add test for idlelib.stackview.StackBrowser.

bpo-33924 [https://bugs.python.org/issue?@action=redirect&bpo=33924]: Change mainmenu.menudefs key ‘windows’ to ‘window’. Every other menudef key is lowercase version of main menu entry.

bpo-33906 [https://bugs.python.org/issue?@action=redirect&bpo=33906]: Rename idlelib.windows as window Match Window on the main menu and remove last plural module name.

bpo-33917 [https://bugs.python.org/issue?@action=redirect&bpo=33917]: Fix and document idlelib/idle_test/template.py. The revised file compiles, runs, and tests OK. idle_test/README.txt explains how to use it to create new IDLE test files.

bpo-33904 [https://bugs.python.org/issue?@action=redirect&bpo=33904]: IDLE: In rstrip, rename class RstripExtension as Rstrip

bpo-33907 [https://bugs.python.org/issue?@action=redirect&bpo=33907]: For consistency and clarity, rename an IDLE module and classes. Module calltips and its class CallTips are now calltip and Calltip. In module calltip_w, class CallTip is now CalltipWindow.

bpo-33856 [https://bugs.python.org/issue?@action=redirect&bpo=33856]: Add “help” in the welcome message of IDLE

bpo-33839 [https://bugs.python.org/issue?@action=redirect&bpo=33839]: IDLE: refactor ToolTip and CallTip and add documentation and tests

bpo-33855 [https://bugs.python.org/issue?@action=redirect&bpo=33855]: Minimally test all IDLE modules. Add missing files, import module, instantiate classes, and check coverage. Check existing files.

bpo-33656 [https://bugs.python.org/issue?@action=redirect&bpo=33656]: On Windows, add API call saying that tk scales for DPI. On Windows 8.1+ or 10, with DPI compatibility properties of the Python binary unchanged, and a monitor resolution greater than 96 DPI, this should make text and lines sharper. It should otherwise have no effect.

bpo-33768 [https://bugs.python.org/issue?@action=redirect&bpo=33768]: Clicking on a context line moves that line to the top of the editor window.

bpo-33763 [https://bugs.python.org/issue?@action=redirect&bpo=33763]: IDLE: Use read-only text widget for code context instead of label widget.

bpo-33664 [https://bugs.python.org/issue?@action=redirect&bpo=33664]: Scroll IDLE editor text by lines. Previously, the mouse wheel and scrollbar slider moved text by a fixed number of pixels, resulting in partial lines at the top of the editor box. The change also applies to the shell and grep output windows, but not to read-only text views.

bpo-33679 [https://bugs.python.org/issue?@action=redirect&bpo=33679]: Enable theme-specific color configuration for Code Context. Use the Highlights tab to see the setting for built-in themes or add settings to custom themes.

bpo-33642 [https://bugs.python.org/issue?@action=redirect&bpo=33642]: Display up to maxlines non-blank lines for Code Context. If there is no current context, show a single blank line.

bpo-33628 [https://bugs.python.org/issue?@action=redirect&bpo=33628]: IDLE: Cleanup codecontext.py and its test.

bpo-33564 [https://bugs.python.org/issue?@action=redirect&bpo=33564]: IDLE’s code context now recognizes async as a block opener.

bpo-21474 [https://bugs.python.org/issue?@action=redirect&bpo=21474]: Update word/identifier definition from ascii to unicode. In text and entry boxes, this affects selection by double-click, movement left/right by control-left/right, and deletion left/right by control-BACKSPACE/DEL.

bpo-33204 [https://bugs.python.org/issue?@action=redirect&bpo=33204]: IDLE: consistently color invalid string prefixes. A ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’. Consistently color as much of the prefix, starting at the right, as is valid. Revise and extend colorizer test.

bpo-32984 [https://bugs.python.org/issue?@action=redirect&bpo=32984]: Set __file__ while running a startup file. Like Python, IDLE optionally runs one startup file in the Shell window before presenting the first interactive input prompt. For IDLE, -s runs a file named in environmental variable IDLESTARTUP or PYTHONSTARTUP; -r file runs file. Python sets __file__ to the startup file name before running the file and unsets it before the first prompt. IDLE now does the same when run normally, without the -n option.

bpo-32940 [https://bugs.python.org/issue?@action=redirect&bpo=32940]: Simplify and rename StringTranslatePseudoMapping in pyparse.

bpo-32916 [https://bugs.python.org/issue?@action=redirect&bpo=32916]: Change str to code in pyparse.

bpo-32905 [https://bugs.python.org/issue?@action=redirect&bpo=32905]: Remove unused code in pyparse module.

bpo-32874 [https://bugs.python.org/issue?@action=redirect&bpo=32874]: Add tests for pyparse.

bpo-32837 [https://bugs.python.org/issue?@action=redirect&bpo=32837]: Using the system and place-dependent default encoding for open() is a bad idea for IDLE’s system and location-independent files.

bpo-32826 [https://bugs.python.org/issue?@action=redirect&bpo=32826]: Add “encoding=utf-8” to open() in IDLE’s test_help_about. GUI test test_file_buttons() only looks at initial ascii-only lines, but failed on systems where open() defaults to ‘ascii’ because readline() internally reads and decodes far enough ahead to encounter a non-ascii character in CREDITS.txt.

bpo-32831 [https://bugs.python.org/issue?@action=redirect&bpo=32831]: Add docstrings and tests for codecontext.

bpo-32765 [https://bugs.python.org/issue?@action=redirect&bpo=32765]: Update configdialog General tab docstring to add new widgets to the widget list.

Tools/Demos

bpo-35884 [https://bugs.python.org/issue?@action=redirect&bpo=35884]: Add a benchmark script for timing various ways to access variables: Tools/scripts/var_access_benchmark.py.

bpo-34989 [https://bugs.python.org/issue?@action=redirect&bpo=34989]: python-gdb.py now handles errors on computing the line number of a Python frame.

bpo-20260 [https://bugs.python.org/issue?@action=redirect&bpo=20260]: Argument Clinic now has non-bitwise unsigned int converters.

bpo-32962 [https://bugs.python.org/issue?@action=redirect&bpo=32962]: python-gdb now catches UnicodeDecodeError exceptions when calling string().

bpo-32962 [https://bugs.python.org/issue?@action=redirect&bpo=32962]: python-gdb now catches ValueError on read_var(): when Python has no debug symbols for example.

bpo-33189 [https://bugs.python.org/issue?@action=redirect&bpo=33189]: pygettext.py now recognizes only literal strings as docstrings and translatable strings, and rejects bytes literals and f-string expressions.

bpo-31920 [https://bugs.python.org/issue?@action=redirect&bpo=31920]: Fixed handling directories as arguments in the pygettext script. Based on patch by Oleg Krasnikov.

bpo-29673 [https://bugs.python.org/issue?@action=redirect&bpo=29673]: Fix pystackv and pystack gdbinit macros.

bpo-25427 [https://bugs.python.org/issue?@action=redirect&bpo=25427]: Remove the pyvenv script in favor of python3 -m venv in order to lower confusion as to what Python interpreter a virtual environment will be created for.

bpo-32885 [https://bugs.python.org/issue?@action=redirect&bpo=32885]: Add an -n flag for Tools/scripts/pathfix.py to disable automatic backup creation (files with ~ suffix).

bpo-32222 [https://bugs.python.org/issue?@action=redirect&bpo=32222]: Fix pygettext not extracting docstrings for functions with type annotated arguments. Patch by Toby Harradine.

bpo-31583 [https://bugs.python.org/issue?@action=redirect&bpo=31583]: Fix 2to3 for using with –add-suffix option but without –output-dir option for relative path to files in current directory.

C API

bpo-35713 [https://bugs.python.org/issue?@action=redirect&bpo=35713]: The PyByteArray_Init() and PyByteArray_Fini() functions have been removed. They did nothing since Python 2.7.4 and Python 3.2.0, were excluded from the limited API (stable ABI), and were not documented.

bpo-33817 [https://bugs.python.org/issue?@action=redirect&bpo=33817]: Fixed _PyBytes_Resize() for empty bytes objects.

bpo-35322 [https://bugs.python.org/issue?@action=redirect&bpo=35322]: Fix memory leak in PyUnicode_EncodeLocale() and PyUnicode_EncodeFSDefault() on error handling.

bpo-35059 [https://bugs.python.org/issue?@action=redirect&bpo=35059]: The following C macros have been converted to static inline functions: Py_INCREF(), Py_DECREF(), Py_XINCREF(), Py_XDECREF(), PyObject_INIT(), PyObject_INIT_VAR().

bpo-35296 [https://bugs.python.org/issue?@action=redirect&bpo=35296]: make install now also installs the internal API: Include/internal/*.h header files.

bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Internal APIs surrounded by #ifdef Py_BUILD_CORE have been moved from Include/*.h headers to new header files Include/internal/pycore_*.h.

bpo-35259 [https://bugs.python.org/issue?@action=redirect&bpo=35259]: Conditionally declare Py_FinalizeEx() (new in 3.6) based on Py_LIMITED_API. Patch by Arthur Neufeld.

bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: The _PyObject_GC_TRACK() and _PyObject_GC_UNTRACK() macros have been removed from the public C API.

bpo-35134 [https://bugs.python.org/issue?@action=redirect&bpo=35134]: Creation of a new Include/cpython/ subdirectory.

bpo-34725 [https://bugs.python.org/issue?@action=redirect&bpo=34725]: Adds _Py_SetProgramFullPath so embedders may override sys.executable

bpo-34910 [https://bugs.python.org/issue?@action=redirect&bpo=34910]: Ensure that PyObject_Print() always returns -1 on error. Patch by Zackery Spytz.

bpo-34523 [https://bugs.python.org/issue?@action=redirect&bpo=34523]: Py_DecodeLocale() and Py_EncodeLocale() now use the UTF-8 encoding on Windows if Py_LegacyWindowsFSEncodingFlag is zero.

bpo-34193 [https://bugs.python.org/issue?@action=redirect&bpo=34193]: Fix pluralization in TypeError messages in getargs.c and typeobject.c: ‘1 argument’ instead of ‘1 arguments’ and ‘1 element’ instead of ‘1 elements’.

bpo-34127 [https://bugs.python.org/issue?@action=redirect&bpo=34127]: Return grammatically correct error message based on argument count. Patch by Karthikeyan Singaravelan.

bpo-23927 [https://bugs.python.org/issue?@action=redirect&bpo=23927]: Fixed SystemError in PyArg_ParseTupleAndKeywords() when the w* format unit is used for optional parameter.

bpo-32455 [https://bugs.python.org/issue?@action=redirect&bpo=32455]: Added PyCompile_OpcodeStackEffectWithJump().

bpo-34008 [https://bugs.python.org/issue?@action=redirect&bpo=34008]: Py_Main() can again be called after Py_Initialize(), as in Python 3.6.

bpo-32500 [https://bugs.python.org/issue?@action=redirect&bpo=32500]: Fixed error messages for PySequence_Size(), PySequence_GetItem(), PySequence_SetItem() and PySequence_DelItem() called with a mapping and PyMapping_Size() called with a sequence.

bpo-33818 [https://bugs.python.org/issue?@action=redirect&bpo=33818]: PyExceptionClass_Name() will now return const char * instead of char *.

bpo-33042 [https://bugs.python.org/issue?@action=redirect&bpo=33042]: Embedding applications may once again call PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption prior to calling Py_Initialize.

bpo-32374 [https://bugs.python.org/issue?@action=redirect&bpo=32374]: Document that m_traverse for multi-phase initialized modules can be called with m_state=NULL, and add a sanity check

bpo-30863 [https://bugs.python.org/issue?@action=redirect&bpo=30863]: PyUnicode_AsWideChar() and PyUnicode_AsWideCharString() no longer cache the wchar_t* representation of string objects.

Python 3.7.0 final

Release date: 2018-06-27

Library

bpo-33851 [https://bugs.python.org/issue?@action=redirect&bpo=33851]: Fix ast.get_docstring() for a node that lacks a docstring.

C API

bpo-33932 [https://bugs.python.org/issue?@action=redirect&bpo=33932]: Calling Py_Initialize() twice does nothing, instead of failing with a fatal error: restore the Python 3.6 behaviour.

Python 3.7.0 release candidate 1

Release date: 2018-06-12

Core and Builtins

bpo-33803 [https://bugs.python.org/issue?@action=redirect&bpo=33803]: Fix a crash in hamt.c caused by enabling GC tracking for an object that hadn’t all of its fields set to NULL.

bpo-33706 [https://bugs.python.org/issue?@action=redirect&bpo=33706]: Fix a crash in Python initialization when parsing the command line options. Thanks Christoph Gohlke for the bug report and the fix!

bpo-30654 [https://bugs.python.org/issue?@action=redirect&bpo=30654]: Fixed reset of the SIGINT handler to SIG_DFL on interpreter shutdown even when there was a custom handler set previously. Patch by Philipp Kerling.

bpo-31849 [https://bugs.python.org/issue?@action=redirect&bpo=31849]: Fix signed/unsigned comparison warning in pyhash.c.

Library

bpo-30167 [https://bugs.python.org/issue?@action=redirect&bpo=30167]: Prevent site.main() exception if PYTHONSTARTUP is set. Patch by Steve Weber.

bpo-33812 [https://bugs.python.org/issue?@action=redirect&bpo=33812]: Datetime instance d with non-None tzinfo, but with d.tzinfo.utcoffset(d) returning None is now treated as naive by the astimezone() method.

bpo-30805 [https://bugs.python.org/issue?@action=redirect&bpo=30805]: Avoid race condition with debug logging

bpo-33694 [https://bugs.python.org/issue?@action=redirect&bpo=33694]: asyncio: Fix a race condition causing data loss on pause_reading()/resume_reading() when using the ProactorEventLoop.

bpo-32493 [https://bugs.python.org/issue?@action=redirect&bpo=32493]: Correct test for uuid_enc_be availability in configure.ac. Patch by Michael Felt.

bpo-33792 [https://bugs.python.org/issue?@action=redirect&bpo=33792]: Add asyncio.WindowsSelectorEventLoopPolicy and asyncio.WindowsProactorEventLoopPolicy.

bpo-33778 [https://bugs.python.org/issue?@action=redirect&bpo=33778]: Update unicodedata’s database to Unicode version 11.0.0.

bpo-33770 [https://bugs.python.org/issue?@action=redirect&bpo=33770]: improve base64 exception message for encoded inputs of invalid length

bpo-33769 [https://bugs.python.org/issue?@action=redirect&bpo=33769]: asyncio/start_tls: Fix error message; cancel callbacks in case of an unhandled error; mark SSLTransport as closed if it is aborted.

bpo-33767 [https://bugs.python.org/issue?@action=redirect&bpo=33767]: The concatenation (+) and repetition (*) sequence operations now raise TypeError instead of SystemError when performed on mmap.mmap objects. Patch by Zackery Spytz.

bpo-33734 [https://bugs.python.org/issue?@action=redirect&bpo=33734]: asyncio/ssl: Fix AttributeError, increase default handshake timeout

bpo-11874 [https://bugs.python.org/issue?@action=redirect&bpo=11874]: Use a better regex when breaking usage into wrappable parts. Avoids bogus assertion errors from custom metavar strings.

bpo-33582 [https://bugs.python.org/issue?@action=redirect&bpo=33582]: Emit a deprecation warning for inspect.formatargspec

Documentation

bpo-33409 [https://bugs.python.org/issue?@action=redirect&bpo=33409]: Clarified the relationship between PEP 538 [https://peps.python.org/pep-0538/]’s PYTHONCOERCECLOCALE and PEP 540’s PYTHONUTF8 mode.

bpo-33736 [https://bugs.python.org/issue?@action=redirect&bpo=33736]: Improve the documentation of asyncio.open_connection(), asyncio.start_server() and their UNIX socket counterparts.

bpo-31432 [https://bugs.python.org/issue?@action=redirect&bpo=31432]: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

Build

bpo-5755 [https://bugs.python.org/issue?@action=redirect&bpo=5755]: Move -Wstrict-prototypes option to CFLAGS_NODIST from OPT. This option emitted annoying warnings when building extension modules written in C++.

Windows

bpo-33720 [https://bugs.python.org/issue?@action=redirect&bpo=33720]: Reduces maximum marshal recursion depth on release builds.

IDLE

bpo-33656 [https://bugs.python.org/issue?@action=redirect&bpo=33656]: On Windows, add API call saying that tk scales for DPI. On Windows 8.1+ or 10, with DPI compatibility properties of the Python binary unchanged, and a monitor resolution greater than 96 DPI, this should make text and lines sharper. It should otherwise have no effect.

bpo-33768 [https://bugs.python.org/issue?@action=redirect&bpo=33768]: Clicking on a context line moves that line to the top of the editor window.

bpo-33763 [https://bugs.python.org/issue?@action=redirect&bpo=33763]: IDLE: Use read-only text widget for code context instead of label widget.

bpo-33664 [https://bugs.python.org/issue?@action=redirect&bpo=33664]: Scroll IDLE editor text by lines. Previously, the mouse wheel and scrollbar slider moved text by a fixed number of pixels, resulting in partial lines at the top of the editor box. The change also applies to the shell and grep output windows, but not to read-only text views.

bpo-33679 [https://bugs.python.org/issue?@action=redirect&bpo=33679]: Enable theme-specific color configuration for Code Context. Use the Highlights tab to see the setting for built-in themes or add settings to custom themes.

bpo-33642 [https://bugs.python.org/issue?@action=redirect&bpo=33642]: Display up to maxlines non-blank lines for Code Context. If there is no current context, show a single blank line.

Python 3.7.0 beta 5

Release date: 2018-05-30

Core and Builtins

bpo-33622 [https://bugs.python.org/issue?@action=redirect&bpo=33622]: Fixed a leak when the garbage collector fails to add an object with the __del__ method or referenced by it into the gc.garbage list. PyGC_Collect() can now be called when an exception is set and preserves it.

bpo-33509 [https://bugs.python.org/issue?@action=redirect&bpo=33509]: Fix module_globals parameter of warnings.warn_explicit(): don’t crash if module_globals is not a dict.

bpo-20104 [https://bugs.python.org/issue?@action=redirect&bpo=20104]: The new os.posix_spawn added in 3.7.0b1 was removed as we are still working on what the API should look like. Expect this in 3.8 instead.

bpo-33475 [https://bugs.python.org/issue?@action=redirect&bpo=33475]: Fixed miscellaneous bugs in converting annotations to strings and optimized parentheses in the string representation.

bpo-33391 [https://bugs.python.org/issue?@action=redirect&bpo=33391]: Fix a leak in set_symmetric_difference().

bpo-28055 [https://bugs.python.org/issue?@action=redirect&bpo=28055]: Fix unaligned accesses in siphash24(). Patch by Rolf Eike Beer.

bpo-32911 [https://bugs.python.org/issue?@action=redirect&bpo=32911]: Due to unexpected compatibility issues discovered during downstream beta testing, reverted bpo-29463 [https://bugs.python.org/issue?@action=redirect&bpo=29463]. docstring field is removed from Module, ClassDef, FunctionDef, and AsyncFunctionDef ast nodes which was added in 3.7a1. Docstring expression is restored as a first statement in their body. Based on patch by Inada Naoki.

bpo-21983 [https://bugs.python.org/issue?@action=redirect&bpo=21983]: Fix a crash in ctypes.cast() in case the type argument is a ctypes structured data type. Patch by Eryk Sun and Oren Milman.

Library

bpo-32751 [https://bugs.python.org/issue?@action=redirect&bpo=32751]: When cancelling the task due to a timeout, asyncio.wait_for() will now wait until the cancellation is complete.

bpo-32684 [https://bugs.python.org/issue?@action=redirect&bpo=32684]: Fix gather to propagate cancellation of itself even with return_exceptions.

bpo-33654 [https://bugs.python.org/issue?@action=redirect&bpo=33654]: Support protocol type switching in SSLTransport.set_protocol().

bpo-33674 [https://bugs.python.org/issue?@action=redirect&bpo=33674]: Pause the transport as early as possible to further reduce the risk of data_received() being called before connection_made().

bpo-33674 [https://bugs.python.org/issue?@action=redirect&bpo=33674]: Fix a race condition in SSLProtocol.connection_made() of asyncio.sslproto: start immediately the handshake instead of using call_soon(). Previously, data_received() could be called before the handshake started, causing the handshake to hang or fail.

bpo-31647 [https://bugs.python.org/issue?@action=redirect&bpo=31647]: Fixed bug where calling write_eof() on a _SelectorSocketTransport after it’s already closed raises AttributeError.

bpo-32610 [https://bugs.python.org/issue?@action=redirect&bpo=32610]: Make asyncio.all_tasks() return only pending tasks.

bpo-32410 [https://bugs.python.org/issue?@action=redirect&bpo=32410]: Avoid blocking on file IO in sendfile fallback code

bpo-33469 [https://bugs.python.org/issue?@action=redirect&bpo=33469]: Fix RuntimeError after closing loop that used run_in_executor

bpo-33672 [https://bugs.python.org/issue?@action=redirect&bpo=33672]: Fix Task.__repr__ crash with Cython’s bogus coroutines

bpo-33654 [https://bugs.python.org/issue?@action=redirect&bpo=33654]: Fix transport.set_protocol() to support switching between asyncio.Protocol and asyncio.BufferedProtocol. Fix loop.start_tls() to work with asyncio.BufferedProtocols.

bpo-33652 [https://bugs.python.org/issue?@action=redirect&bpo=33652]: Pickles of type variables and subscripted generics are now future-proof and compatible with older Python versions.

bpo-32493 [https://bugs.python.org/issue?@action=redirect&bpo=32493]: Fixed uuid.uuid1() on FreeBSD.

bpo-33618 [https://bugs.python.org/issue?@action=redirect&bpo=33618]: Finalize and document preliminary and experimental TLS 1.3 support with OpenSSL 1.1.1

bpo-33623 [https://bugs.python.org/issue?@action=redirect&bpo=33623]: Fix possible SIGSGV when asyncio.Future is created in __del__

bpo-30877 [https://bugs.python.org/issue?@action=redirect&bpo=30877]: Fixed a bug in the Python implementation of the JSON decoder that prevented the cache of parsed strings from clearing after finishing the decoding. Based on patch by c-fos.

bpo-33570 [https://bugs.python.org/issue?@action=redirect&bpo=33570]: Change TLS 1.3 cipher suite settings for compatibility with OpenSSL 1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3 ciphers enabled by default.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Do not simplify arguments to typing.Union. Now Union[Manager, Employee] is not simplified to Employee at runtime. Such simplification previously caused several bugs and limited possibilities for introspection.

bpo-33540 [https://bugs.python.org/issue?@action=redirect&bpo=33540]: Add a new block_on_close class attribute to ForkingMixIn and ThreadingMixIn classes of socketserver.

bpo-33548 [https://bugs.python.org/issue?@action=redirect&bpo=33548]: tempfile._candidate_tempdir_list should consider common TEMP locations

bpo-33109 [https://bugs.python.org/issue?@action=redirect&bpo=33109]: argparse subparsers are once again not required by default, reverting the change in behavior introduced by bpo-26510 [https://bugs.python.org/issue?@action=redirect&bpo=26510] in 3.7.0a2.

bpo-33536 [https://bugs.python.org/issue?@action=redirect&bpo=33536]: dataclasses.make_dataclass now checks for invalid field names and duplicate fields. Also, added a check for invalid field specifications.

bpo-33542 [https://bugs.python.org/issue?@action=redirect&bpo=33542]: Prevent uuid.get_node from using a DUID instead of a MAC on Windows. Patch by Zvi Effron

bpo-26819 [https://bugs.python.org/issue?@action=redirect&bpo=26819]: Fix race condition with ReadTransport.resume_reading in Windows proactor event loop.

Fix failure in typing.get_type_hints() when ClassVar was provided as a string forward reference.

bpo-33505 [https://bugs.python.org/issue?@action=redirect&bpo=33505]: Optimize asyncio.ensure_future() by reordering if checks: 1.17x faster.

bpo-33497 [https://bugs.python.org/issue?@action=redirect&bpo=33497]: Add errors param to cgi.parse_multipart and make an encoding in FieldStorage use the given errors (needed for Twisted). Patch by Amber Brown.

bpo-33495 [https://bugs.python.org/issue?@action=redirect&bpo=33495]: Change dataclasses.Fields repr to use the repr of each of its members, instead of str. This makes it more clear what each field actually represents. This is especially true for the ‘type’ member.

bpo-33453 [https://bugs.python.org/issue?@action=redirect&bpo=33453]: Fix dataclasses to work if using literal string type annotations or if using PEP 563 “Postponed Evaluation of Annotations”. Only specific string prefixes are detected for both ClassVar (“ClassVar” and “typing.ClassVar”) and InitVar (“InitVar” and “dataclasses.InitVar”).

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Minor fixes in typing module: add annotations to NamedTuple.__new__, pass *args and **kwds in Generic.__new__. Original PRs by Paulius Šarka and Chad Dombrova.

bpo-20087 [https://bugs.python.org/issue?@action=redirect&bpo=20087]: Updated alias mapping with glibc 2.27 supported locales.

bpo-33422 [https://bugs.python.org/issue?@action=redirect&bpo=33422]: Fix trailing quotation marks getting deleted when looking up byte/string literals on pydoc. Patch by Andrés Delfino.

bpo-28167 [https://bugs.python.org/issue?@action=redirect&bpo=28167]: The function platform.linux_distribution and platform.dist now trigger a DeprecationWarning and have been marked for removal in Python 3.8

bpo-33197 [https://bugs.python.org/issue?@action=redirect&bpo=33197]: Update error message when constructing invalid inspect.Parameters Patch by Donghee Na.

bpo-33263 [https://bugs.python.org/issue?@action=redirect&bpo=33263]: Fix FD leak in _SelectorSocketTransport Patch by Vlad Starostin.

bpo-32861 [https://bugs.python.org/issue?@action=redirect&bpo=32861]: The urllib.robotparser’s __str__ representation now includes wildcard entries and the “Crawl-delay” and “Request-rate” fields. Patch by Michael Lazar.

bpo-32257 [https://bugs.python.org/issue?@action=redirect&bpo=32257]: The ssl module now contains OP_NO_RENEGOTIATION constant, available with OpenSSL 1.1.0h or 1.1.1.

bpo-16865 [https://bugs.python.org/issue?@action=redirect&bpo=16865]: Support arrays >=2GiB in ctypes. Patch by Segev Finer.

Documentation

bpo-23859 [https://bugs.python.org/issue?@action=redirect&bpo=23859]: Document that asyncio.wait() does not cancel its futures on timeout.

bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436]: Document PEP 567 [https://peps.python.org/pep-0567/] changes to asyncio.

bpo-33604 [https://bugs.python.org/issue?@action=redirect&bpo=33604]: Update HMAC md5 default to a DeprecationWarning, bump removal to 3.8.

bpo-33503 [https://bugs.python.org/issue?@action=redirect&bpo=33503]: Fix broken pypi link

bpo-33421 [https://bugs.python.org/issue?@action=redirect&bpo=33421]: Add missing documentation for typing.AsyncContextManager.

Tests

bpo-33655 [https://bugs.python.org/issue?@action=redirect&bpo=33655]: Ignore test_posix_fallocate failures on BSD platforms that might be due to running on ZFS.

bpo-32604 [https://bugs.python.org/issue?@action=redirect&bpo=32604]: Remove the _xxsubinterpreters module (meant for testing) and associated helpers. This module was originally added recently in 3.7b1.

Build

bpo-33614 [https://bugs.python.org/issue?@action=redirect&bpo=33614]: Ensures module definition files for the stable ABI on Windows are correctly regenerated.

bpo-33522 [https://bugs.python.org/issue?@action=redirect&bpo=33522]: Enable CI builds on Visual Studio Team Services at https://python.visualstudio.com/cpython

bpo-33012 [https://bugs.python.org/issue?@action=redirect&bpo=33012]: Add -Wno-cast-function-type for gcc 8 for silencing warnings about function casts like casting to PyCFunction in method definition lists.

macOS

bpo-13631 [https://bugs.python.org/issue?@action=redirect&bpo=13631]: The .editrc file in user’s home directory is now processed correctly during the readline initialization through editline emulation on macOS.

IDLE

bpo-33628 [https://bugs.python.org/issue?@action=redirect&bpo=33628]: IDLE: Cleanup codecontext.py and its test.

bpo-33564 [https://bugs.python.org/issue?@action=redirect&bpo=33564]: IDLE’s code context now recognizes async as a block opener.

bpo-32831 [https://bugs.python.org/issue?@action=redirect&bpo=32831]: Add docstrings and tests for codecontext.

Python 3.7.0 beta 4

Release date: 2018-05-02

Core and Builtins

bpo-33363 [https://bugs.python.org/issue?@action=redirect&bpo=33363]: Raise a SyntaxError for async with and async for statements outside of async functions.

bpo-33128 [https://bugs.python.org/issue?@action=redirect&bpo=33128]: Fix a bug that causes PathFinder to appear twice on sys.meta_path. Patch by Pablo Galindo Salgado.

bpo-33312 [https://bugs.python.org/issue?@action=redirect&bpo=33312]: Fixed clang ubsan (undefined behavior sanitizer) warnings in dictobject.c by adjusting how the internal struct _dictkeysobject shared keys structure is declared.

bpo-33231 [https://bugs.python.org/issue?@action=redirect&bpo=33231]: Fix potential memory leak in normalizestring().

bpo-33205 [https://bugs.python.org/issue?@action=redirect&bpo=33205]: Change dict growth function from round_up_to_power_2(used*2+hashtable_size/2) to round_up_to_power_2(used*3). Previously, dict is shrunk only when used == 0. Now dict has more chance to be shrunk.

bpo-29922 [https://bugs.python.org/issue?@action=redirect&bpo=29922]: Improved error messages in ‘async with’ when __aenter__() or __aexit__() return non-awaitable object.

bpo-33199 [https://bugs.python.org/issue?@action=redirect&bpo=33199]: Fix ma_version_tag in dict implementation is uninitialized when copying from key-sharing dict.

Library

bpo-33281 [https://bugs.python.org/issue?@action=redirect&bpo=33281]: Fix ctypes.util.find_library regression on macOS.

bpo-33383 [https://bugs.python.org/issue?@action=redirect&bpo=33383]: Fixed crash in the get() method of the dbm.ndbm database object when it is called with a single argument.

bpo-33329 [https://bugs.python.org/issue?@action=redirect&bpo=33329]: Fix multiprocessing regression on newer glibcs

bpo-991266 [https://bugs.python.org/issue?@action=redirect&bpo=991266]: Fix quoting of the Comment attribute of http.cookies.SimpleCookie.

bpo-33131 [https://bugs.python.org/issue?@action=redirect&bpo=33131]: Upgrade bundled version of pip to 10.0.1.

bpo-33308 [https://bugs.python.org/issue?@action=redirect&bpo=33308]: Fixed a crash in the parser module when converting an ST object to a tree of tuples or lists with line_info=False and col_info=True.

bpo-33266 [https://bugs.python.org/issue?@action=redirect&bpo=33266]: lib2to3 now recognizes rf'...' strings.

bpo-11594 [https://bugs.python.org/issue?@action=redirect&bpo=11594]: Ensure line-endings are respected when using lib2to3.

bpo-33254 [https://bugs.python.org/issue?@action=redirect&bpo=33254]: Have importlib.resources.contents() and importlib.abc.ResourceReader.contents() return an iterable instead of an iterator.

bpo-33256 [https://bugs.python.org/issue?@action=redirect&bpo=33256]: Fix display of <module> call in the html produced by cgitb.html(). Patch by Stéphane Blondon.

bpo-33185 [https://bugs.python.org/issue?@action=redirect&bpo=33185]: Fixed regression when running pydoc with the -m switch. (The regression was introduced in 3.7.0b3 by the resolution of bpo-33053 [https://bugs.python.org/issue?@action=redirect&bpo=33053]) This fix also changed pydoc to add os.getcwd() to sys.path when necessary, rather than adding ".".

bpo-33169 [https://bugs.python.org/issue?@action=redirect&bpo=33169]: Delete entries of None in sys.path_importer_cache when importlib.machinery.invalidate_caches() is called.

bpo-33217 [https://bugs.python.org/issue?@action=redirect&bpo=33217]: Deprecate looking up non-Enum objects in Enum classes and Enum members (will raise TypeError in 3.8+).

bpo-33203 [https://bugs.python.org/issue?@action=redirect&bpo=33203]: random.Random.choice() now raises IndexError for empty sequences consistently even when called from subclasses without a getrandbits() implementation.

bpo-33224 [https://bugs.python.org/issue?@action=redirect&bpo=33224]: Update difflib.mdiff() for PEP 479 [https://peps.python.org/pep-0479/]. Convert an uncaught StopIteration in a generator into a return-statement.

bpo-33209 [https://bugs.python.org/issue?@action=redirect&bpo=33209]: End framing at the end of C implementation of pickle.Pickler.dump().

bpo-20104 [https://bugs.python.org/issue?@action=redirect&bpo=20104]: Improved error handling and fixed a reference leak in os.posix_spawn().

bpo-33175 [https://bugs.python.org/issue?@action=redirect&bpo=33175]: In dataclasses, Field.__set_name__ now looks up the __set_name__ special method on the class, not the instance, of the default value.

bpo-33097 [https://bugs.python.org/issue?@action=redirect&bpo=33097]: Raise RuntimeError when executor.submit is called during interpreter shutdown.

bpo-31908 [https://bugs.python.org/issue?@action=redirect&bpo=31908]: Fix output of cover files for trace module command-line tool. Previously emitted cover files only when --missing option was used. Patch by Michael Selik.

Documentation

bpo-33378 [https://bugs.python.org/issue?@action=redirect&bpo=33378]: Add Korean language switcher for https://docs.python.org/3/

bpo-33276 [https://bugs.python.org/issue?@action=redirect&bpo=33276]: Clarify that the __path__ attribute on modules cannot be just any value.

bpo-33201 [https://bugs.python.org/issue?@action=redirect&bpo=33201]: Modernize documentation for writing C extension types.

bpo-33195 [https://bugs.python.org/issue?@action=redirect&bpo=33195]: Deprecate Py_UNICODE usage in c-api/arg document. Py_UNICODE related APIs are deprecated since Python 3.3, but it is missed in the document.

bpo-8243 [https://bugs.python.org/issue?@action=redirect&bpo=8243]: Add a note about curses.addch and curses.addstr exception behavior when writing outside a window, or pad.

bpo-32337 [https://bugs.python.org/issue?@action=redirect&bpo=32337]: Update documentation related with dict order.

Tests

bpo-33358 [https://bugs.python.org/issue?@action=redirect&bpo=33358]: Fix test_embed.test_pre_initialization_sys_options() when the interpreter is built with --enable-shared.

Build

bpo-33394 [https://bugs.python.org/issue?@action=redirect&bpo=33394]: Enable the verbose build for extension modules, when GNU make is passed macros on the command line.

bpo-33393 [https://bugs.python.org/issue?@action=redirect&bpo=33393]: Update config.guess and config.sub files.

bpo-33377 [https://bugs.python.org/issue?@action=redirect&bpo=33377]: Add new triplets for mips r6 and riscv variants (used in extension suffixes).

bpo-32232 [https://bugs.python.org/issue?@action=redirect&bpo=32232]: By default, modules configured in Modules/Setup are no longer built with -DPy_BUILD_CORE. Instead, modules that specifically need that preprocessor definition include it in their individual entries.

bpo-33182 [https://bugs.python.org/issue?@action=redirect&bpo=33182]: The embedding tests can once again be built with clang 6.0

Windows

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update Windows installer to use OpenSSL 1.1.0h.

macOS

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update macOS installer build to use OpenSSL 1.1.0h.

IDLE

bpo-21474 [https://bugs.python.org/issue?@action=redirect&bpo=21474]: Update word/identifier definition from ascii to unicode. In text and entry boxes, this affects selection by double-click, movement left/right by control-left/right, and deletion left/right by control-BACKSPACE/DEL.

bpo-33204 [https://bugs.python.org/issue?@action=redirect&bpo=33204]: IDLE: consistently color invalid string prefixes. A ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’. Consistently color as much of the prefix, starting at the right, as is valid. Revise and extend colorizer test.

Tools/Demos

bpo-33189 [https://bugs.python.org/issue?@action=redirect&bpo=33189]: pygettext.py now recognizes only literal strings as docstrings and translatable strings, and rejects bytes literals and f-string expressions.

bpo-31920 [https://bugs.python.org/issue?@action=redirect&bpo=31920]: Fixed handling directories as arguments in the pygettext script. Based on patch by Oleg Krasnikov.

bpo-29673 [https://bugs.python.org/issue?@action=redirect&bpo=29673]: Fix pystackv and pystack gdbinit macros.

bpo-31583 [https://bugs.python.org/issue?@action=redirect&bpo=31583]: Fix 2to3 for using with –add-suffix option but without –output-dir option for relative path to files in current directory.

Python 3.7.0 beta 3

Release date: 2018-03-29

Security

bpo-33136 [https://bugs.python.org/issue?@action=redirect&bpo=33136]: Harden ssl module against LibreSSL CVE 2018-8970 [https://www.cve.org/CVERecord?id=CVE-2018-8970]. X509_VERIFY_PARAM_set1_host() is called with an explicit namelen. A new test ensures that NULL bytes are not allowed.

bpo-33001 [https://bugs.python.org/issue?@action=redirect&bpo=33001]: Minimal fix to prevent buffer overrun in os.symlink on Windows

bpo-32981 [https://bugs.python.org/issue?@action=redirect&bpo=32981]: Regexes in difflib and poplib were vulnerable to catastrophic backtracking. These regexes formed potential DOS vectors (REDOS). They have been refactored. This resolves CVE 2018-1060 [https://www.cve.org/CVERecord?id=CVE-2018-1060] and CVE 2018-1061 [https://www.cve.org/CVERecord?id=CVE-2018-1061]. Patch by Jamie Davis.

Core and Builtins

bpo-33053 [https://bugs.python.org/issue?@action=redirect&bpo=33053]: When using the -m switch, sys.path[0] is now explicitly expanded as the starting working directory, rather than being left as the empty path (which allows imports from the current working directory at the time of the import)

bpo-33018 [https://bugs.python.org/issue?@action=redirect&bpo=33018]: Improve consistency of errors raised by issubclass() when called with a non-class and an abstract base class as the first and second arguments, respectively. Patch by Josh Bronson.

bpo-33041 [https://bugs.python.org/issue?@action=redirect&bpo=33041]: Fixed jumping when the function contains an async for loop.

bpo-33026 [https://bugs.python.org/issue?@action=redirect&bpo=33026]: Fixed jumping out of “with” block by setting f_lineno.

bpo-33005 [https://bugs.python.org/issue?@action=redirect&bpo=33005]: Fix a crash on fork when using a custom memory allocator (ex: using PYTHONMALLOC env var). _PyGILState_Reinit() and _PyInterpreterState_Enable() now use the default RAW memory allocator to allocate a new interpreters mutex on fork.

bpo-17288 [https://bugs.python.org/issue?@action=redirect&bpo=17288]: Prevent jumps from ‘return’ and ‘exception’ trace events.

bpo-32836 [https://bugs.python.org/issue?@action=redirect&bpo=32836]: Don’t use temporary variables in cases of list/dict/set comprehensions

Library

bpo-33141 [https://bugs.python.org/issue?@action=redirect&bpo=33141]: Have Field objects pass through __set_name__ to their default values, if they have their own __set_name__.

bpo-33096 [https://bugs.python.org/issue?@action=redirect&bpo=33096]: Allow ttk.Treeview.insert to insert iid that has a false boolean value. Note iid=0 and iid=False would be same. Patch by Garvit Khatri.

bpo-32873 [https://bugs.python.org/issue?@action=redirect&bpo=32873]: Treat type variables and special typing forms as immutable by copy and pickle. This fixes several minor issues and inconsistencies, and improves backwards compatibility with Python 3.6.

bpo-33134 [https://bugs.python.org/issue?@action=redirect&bpo=33134]: When computing dataclass’s __hash__, use the lookup table to contain the function which returns the __hash__ value. This is an improvement over looking up a string, and then testing that string to see what to do.

bpo-33127 [https://bugs.python.org/issue?@action=redirect&bpo=33127]: The ssl module now compiles with LibreSSL 2.7.1.

bpo-32505 [https://bugs.python.org/issue?@action=redirect&bpo=32505]: Raise TypeError if a member variable of a dataclass is of type Field, but doesn’t have a type annotation.

bpo-33078 [https://bugs.python.org/issue?@action=redirect&bpo=33078]: Fix the failure on OSX caused by the tests relying on sem_getvalue

bpo-33116 [https://bugs.python.org/issue?@action=redirect&bpo=33116]: Add ‘Field’ to dataclasses.__all__.

bpo-32896 [https://bugs.python.org/issue?@action=redirect&bpo=32896]: Fix an error where subclassing a dataclass with a field that uses a default_factory would generate an incorrect class.

bpo-33100 [https://bugs.python.org/issue?@action=redirect&bpo=33100]: Dataclasses: If a field has a default value that’s a MemberDescriptorType, then it’s from that field being in __slots__, not an actual default value.

bpo-32953 [https://bugs.python.org/issue?@action=redirect&bpo=32953]: If a non-dataclass inherits from a frozen dataclass, allow attributes to be added to the derived class. Only attributes from the frozen dataclass cannot be assigned to. Require all dataclasses in a hierarchy to be either all frozen or all non-frozen.

bpo-33061 [https://bugs.python.org/issue?@action=redirect&bpo=33061]: Add missing NoReturn to __all__ in typing.py

bpo-33078 [https://bugs.python.org/issue?@action=redirect&bpo=33078]: Fix the size handling in multiprocessing.Queue when a pickling error occurs.

bpo-33064 [https://bugs.python.org/issue?@action=redirect&bpo=33064]: lib2to3 now properly supports trailing commas after *args and **kwargs in function signatures.

bpo-33056 [https://bugs.python.org/issue?@action=redirect&bpo=33056]: FIX properly close leaking fds in concurrent.futures.ProcessPoolExecutor.

bpo-33021 [https://bugs.python.org/issue?@action=redirect&bpo=33021]: Release the GIL during fstat() calls, avoiding hang of all threads when calling mmap.mmap(), os.urandom(), and random.seed(). Patch by Nir Soffer.

bpo-31804 [https://bugs.python.org/issue?@action=redirect&bpo=31804]: Avoid failing in multiprocessing.Process if the standard streams are closed or None at exit.

bpo-33037 [https://bugs.python.org/issue?@action=redirect&bpo=33037]: Skip sending/receiving data after SSL transport closing.

bpo-27683 [https://bugs.python.org/issue?@action=redirect&bpo=27683]: Fix a regression in ipaddress that result of hosts() is empty when the network is constructed by a tuple containing an integer mask and only 1 bit left for addresses.

bpo-32999 [https://bugs.python.org/issue?@action=redirect&bpo=32999]: Fix C implementation of ABC.__subclasscheck__(cls, subclass) crashed when subclass is not a type object.

bpo-33009 [https://bugs.python.org/issue?@action=redirect&bpo=33009]: Fix inspect.signature() for single-parameter partialmethods.

bpo-32969 [https://bugs.python.org/issue?@action=redirect&bpo=32969]: Expose several missing constants in zlib and fix corresponding documentation.

bpo-32056 [https://bugs.python.org/issue?@action=redirect&bpo=32056]: Improved exceptions raised for invalid number of channels and sample width when read an audio file in modules aifc, wave and sunau.

bpo-32844 [https://bugs.python.org/issue?@action=redirect&bpo=32844]: Fix wrong redirection of a low descriptor (0 or 1) to stderr in subprocess if another low descriptor is closed.

bpo-32857 [https://bugs.python.org/issue?@action=redirect&bpo=32857]: In tkinter, after_cancel(None) now raises a ValueError instead of canceling the first scheduled function. Patch by Cheryl Sabella.

bpo-31639 [https://bugs.python.org/issue?@action=redirect&bpo=31639]: http.server now exposes a ThreadedHTTPServer class and uses it when the module is run with -m to cope with web browsers pre-opening sockets.

bpo-27645 [https://bugs.python.org/issue?@action=redirect&bpo=27645]: sqlite3.Connection now exposes a backup method, if the underlying SQLite library is at version 3.6.11 or higher. Patch by Lele Gaifax.

Documentation

bpo-33126 [https://bugs.python.org/issue?@action=redirect&bpo=33126]: Document PyBuffer_ToContiguous().

bpo-27212 [https://bugs.python.org/issue?@action=redirect&bpo=27212]: Modify documentation for the islice() recipe to consume initial values up to the start index.

bpo-28247 [https://bugs.python.org/issue?@action=redirect&bpo=28247]: Update zipapp documentation to describe how to make standalone applications.

bpo-18802 [https://bugs.python.org/issue?@action=redirect&bpo=18802]: Documentation changes for ipaddress. Patch by Jon Foster and Berker Peksag.

bpo-27428 [https://bugs.python.org/issue?@action=redirect&bpo=27428]: Update documentation to clarify that WindowsRegistryFinder implements MetaPathFinder. (Patch by Himanshu Lakhara)

Tests

bpo-32872 [https://bugs.python.org/issue?@action=redirect&bpo=32872]: Avoid regrtest compatibility issue with namespace packages.

bpo-32517 [https://bugs.python.org/issue?@action=redirect&bpo=32517]: Fix failing test_asyncio on macOS 10.12.2+ due to transport of KqueueSelector loop was not being closed.

bpo-19417 [https://bugs.python.org/issue?@action=redirect&bpo=19417]: Add test_bdb.py.

Build

bpo-33163 [https://bugs.python.org/issue?@action=redirect&bpo=33163]: Upgrade pip to 9.0.3 and setuptools to v39.0.1.

Windows

bpo-33016 [https://bugs.python.org/issue?@action=redirect&bpo=33016]: Fix potential use of uninitialized memory in nt._getfinalpathname

bpo-32903 [https://bugs.python.org/issue?@action=redirect&bpo=32903]: Fix a memory leak in os.chdir() on Windows if the current directory is set to a UNC path.

macOS

bpo-32726 [https://bugs.python.org/issue?@action=redirect&bpo=32726]: Build and link with private copy of Tcl/Tk 8.6 for the macOS 10.6+ installer. The 10.9+ installer variant already does this. This means that the Python 3.7 provided by the python.org macOS installers no longer need or use any external versions of Tcl/Tk, either system-provided or user-installed, such as ActiveTcl.

IDLE

bpo-32984 [https://bugs.python.org/issue?@action=redirect&bpo=32984]: Set __file__ while running a startup file. Like Python, IDLE optionally runs one startup file in the Shell window before presenting the first interactive input prompt. For IDLE, -s runs a file named in environmental variable IDLESTARTUP or PYTHONSTARTUP; -r file runs file. Python sets __file__ to the startup file name before running the file and unsets it before the first prompt. IDLE now does the same when run normally, without the -n option.

bpo-32940 [https://bugs.python.org/issue?@action=redirect&bpo=32940]: Simplify and rename StringTranslatePseudoMapping in pyparse.

Tools/Demos

bpo-32885 [https://bugs.python.org/issue?@action=redirect&bpo=32885]: Add an -n flag for Tools/scripts/pathfix.py to disable automatic backup creation (files with ~ suffix).

C API

bpo-33042 [https://bugs.python.org/issue?@action=redirect&bpo=33042]: Embedding applications may once again call PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption prior to calling Py_Initialize.

bpo-32374 [https://bugs.python.org/issue?@action=redirect&bpo=32374]: Document that m_traverse for multi-phase initialized modules can be called with m_state=NULL, and add a sanity check

Python 3.7.0 beta 2

Release date: 2018-02-27

Security

bpo-28414 [https://bugs.python.org/issue?@action=redirect&bpo=28414]: The ssl module now allows users to perform their own IDN en/decoding when using SNI.

Core and Builtins

bpo-32889 [https://bugs.python.org/issue?@action=redirect&bpo=32889]: Update Valgrind suppression list to account for the rename of Py_ADDRESS_IN_RANG to address_in_range.

bpo-31356 [https://bugs.python.org/issue?@action=redirect&bpo=31356]: Remove the new API added in bpo-31356 [https://bugs.python.org/issue?@action=redirect&bpo=31356] (gc.ensure_disabled() context manager).

bpo-32305 [https://bugs.python.org/issue?@action=redirect&bpo=32305]: For namespace packages, ensure that both __file__ and __spec__.origin are set to None.

bpo-32303 [https://bugs.python.org/issue?@action=redirect&bpo=32303]: Make sure __spec__.loader matches __loader__ for namespace packages.

bpo-32711 [https://bugs.python.org/issue?@action=redirect&bpo=32711]: Fix the warning messages for Python/ast_unparse.c. Patch by Stéphane Wirtel

bpo-32583 [https://bugs.python.org/issue?@action=redirect&bpo=32583]: Fix possible crashing in builtin Unicode decoders caused by write out-of-bound errors when using customized decode error handlers.

Library

bpo-32960 [https://bugs.python.org/issue?@action=redirect&bpo=32960]: For dataclasses, disallow inheriting frozen from non-frozen classes, and also disallow inheriting non-frozen from frozen classes. This restriction will be relaxed at a future date.

bpo-32713 [https://bugs.python.org/issue?@action=redirect&bpo=32713]: Fixed tarfile.itn handling of out-of-bounds float values. Patch by Joffrey Fuhrer.

bpo-32951 [https://bugs.python.org/issue?@action=redirect&bpo=32951]: Direct instantiation of SSLSocket and SSLObject objects is now prohibited. The constructors were never documented, tested, or designed as public constructors. Users were suppose to use ssl.wrap_socket() or SSLContext.

bpo-32929 [https://bugs.python.org/issue?@action=redirect&bpo=32929]: Remove the tri-state parameter “hash”, and add the boolean “unsafe_hash”. If unsafe_hash is True, add a __hash__ function, but if a __hash__ exists, raise TypeError. If unsafe_hash is False, add a __hash__ based on the values of eq= and frozen=. The unsafe_hash=False behavior is the same as the old hash=None behavior. unsafe_hash=False is the default, just as hash=None used to be.

bpo-32947 [https://bugs.python.org/issue?@action=redirect&bpo=32947]: Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for TLSv1.3 for future compatibility with OpenSSL 1.1.1.

bpo-30622 [https://bugs.python.org/issue?@action=redirect&bpo=30622]: The ssl module now detects missing NPN support in LibreSSL.

bpo-32922 [https://bugs.python.org/issue?@action=redirect&bpo=32922]: dbm.open() now encodes filename with the filesystem encoding rather than default encoding.

bpo-32859 [https://bugs.python.org/issue?@action=redirect&bpo=32859]: In os.dup2, don’t check every call whether the dup3 syscall exists or not.

bpo-32556 [https://bugs.python.org/issue?@action=redirect&bpo=32556]: nt._getfinalpathname, nt._getvolumepathname and nt._getdiskusage now correctly convert from bytes.

bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988]: Emit a DeprecationWarning when using or importing an ABC directly from collections rather than from collections.abc.

bpo-21060 [https://bugs.python.org/issue?@action=redirect&bpo=21060]: Rewrite confusing message from setup.py upload from “No dist file created in earlier command” to the more helpful “Must create and upload files in one command”.

bpo-32852 [https://bugs.python.org/issue?@action=redirect&bpo=32852]: Make sure sys.argv remains as a list when running trace.

bpo-31333 [https://bugs.python.org/issue?@action=redirect&bpo=31333]: _abc module is added. It is a speedup module with C implementations for various functions and methods in abc. Creating an ABC subclass and calling isinstance or issubclass with an ABC subclass are up to 1.5x faster. In addition, this makes Python start-up up to 10% faster. Note that the new implementation hides internal registry and caches, previously accessible via private attributes _abc_registry, _abc_cache, and _abc_negative_cache. There are three debugging helper methods that can be used instead _dump_registry, _abc_registry_clear, and _abc_caches_clear.

bpo-32841 [https://bugs.python.org/issue?@action=redirect&bpo=32841]: Fixed asyncio.Condition issue which silently ignored cancellation after notifying and cancelling a conditional lock. Patch by Bar Harel.

bpo-32819 [https://bugs.python.org/issue?@action=redirect&bpo=32819]: ssl.match_hostname() has been simplified and no longer depends on re and ipaddress module for wildcard and IP addresses. Error reporting for invalid wildcards has been improved.

bpo-32394 [https://bugs.python.org/issue?@action=redirect&bpo=32394]: socket: Remove TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older version Windows during run-time.

bpo-31787 [https://bugs.python.org/issue?@action=redirect&bpo=31787]: Fixed refleaks of __init__() methods in various modules. (Contributed by Oren Milman)

bpo-30157 [https://bugs.python.org/issue?@action=redirect&bpo=30157]: Fixed guessing quote and delimiter in csv.Sniffer.sniff() when only the last field is quoted. Patch by Jake Davis.

bpo-32792 [https://bugs.python.org/issue?@action=redirect&bpo=32792]: collections.ChainMap() preserves the order of the underlying mappings.

bpo-32775 [https://bugs.python.org/issue?@action=redirect&bpo=32775]: fnmatch.translate() no longer produces patterns which contain set operations. Sets starting with ‘[’ or containing ‘–’, ‘&&’, ‘~~’ or ‘||’ will be interpreted differently in regular expressions in future versions. Currently they emit warnings. fnmatch.translate() now avoids producing patterns containing such sets by accident.

bpo-32622 [https://bugs.python.org/issue?@action=redirect&bpo=32622]: Implement native fast sendfile for Windows proactor event loop.

bpo-32777 [https://bugs.python.org/issue?@action=redirect&bpo=32777]: Fix a rare but potential pre-exec child process deadlock in subprocess on POSIX systems when marking file descriptors inheritable on exec in the child process. This bug appears to have been introduced in 3.4.

bpo-32647 [https://bugs.python.org/issue?@action=redirect&bpo=32647]: The ctypes module used to depend on indirect linking for dlopen. The shared extension is now explicitly linked against libdl on platforms with dl.

bpo-32741 [https://bugs.python.org/issue?@action=redirect&bpo=32741]: Implement asyncio.TimerHandle.when() method.

bpo-32691 [https://bugs.python.org/issue?@action=redirect&bpo=32691]: Use mod_spec.parent when running modules with pdb

bpo-32734 [https://bugs.python.org/issue?@action=redirect&bpo=32734]: Fixed asyncio.Lock() safety issue which allowed acquiring and locking the same lock multiple times, without it being free. Patch by Bar Harel.

bpo-32727 [https://bugs.python.org/issue?@action=redirect&bpo=32727]: Do not include name field in SMTP envelope from address. Patch by Stéphane Wirtel

bpo-31453 [https://bugs.python.org/issue?@action=redirect&bpo=31453]: Add TLSVersion constants and SSLContext.maximum_version / minimum_version attributes. The new API wraps OpenSSL 1.1 https://web.archive.org/web/20180309043602/https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html feature.

bpo-24334 [https://bugs.python.org/issue?@action=redirect&bpo=24334]: Internal implementation details of ssl module were cleaned up. The SSLSocket has one less layer of indirection. Owner and session information are now handled by the SSLSocket and SSLObject constructor. Channel binding implementation has been simplified.

bpo-31848 [https://bugs.python.org/issue?@action=redirect&bpo=31848]: Fix the error handling in Aifc_read.initfp() when the SSND chunk is not found. Patch by Zackery Spytz.

bpo-32585 [https://bugs.python.org/issue?@action=redirect&bpo=32585]: Add Ttk spinbox widget to tkinter.ttk. Patch by Alan D Moore.

bpo-32221 [https://bugs.python.org/issue?@action=redirect&bpo=32221]: Various functions returning tuple containing IPv6 addresses now omit %scope part since the same information is already encoded in scopeid tuple item. Especially this speeds up socket.recvfrom() when it receives multicast packet since useless resolving of network interface name is omitted.

bpo-30693 [https://bugs.python.org/issue?@action=redirect&bpo=30693]: The TarFile class now recurses directories in a reproducible way.

bpo-30693 [https://bugs.python.org/issue?@action=redirect&bpo=30693]: The ZipFile class now recurses directories in a reproducible way.

Documentation

bpo-28124 [https://bugs.python.org/issue?@action=redirect&bpo=28124]: The ssl module function ssl.wrap_socket() has been de-emphasized and deprecated in favor of the more secure and efficient SSLContext.wrap_socket() method.

bpo-17232 [https://bugs.python.org/issue?@action=redirect&bpo=17232]: Clarify docs for -O and -OO. Patch by Terry Reedy.

bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436]: Add documentation for the contextvars module (PEP 567).

bpo-32800 [https://bugs.python.org/issue?@action=redirect&bpo=32800]: Update link to w3c doc for xml default namespaces.

bpo-11015 [https://bugs.python.org/issue?@action=redirect&bpo=11015]: Update test.support documentation.

bpo-8722 [https://bugs.python.org/issue?@action=redirect&bpo=8722]: Document __getattr__() behavior when property get() method raises AttributeError.

bpo-32614 [https://bugs.python.org/issue?@action=redirect&bpo=32614]: Modify RE examples in documentation to use raw strings to prevent DeprecationWarning and add text to REGEX HOWTO to highlight the deprecation.

bpo-31972 [https://bugs.python.org/issue?@action=redirect&bpo=31972]: Improve docstrings for pathlib.PurePath subclasses.

Tests

bpo-31809 [https://bugs.python.org/issue?@action=redirect&bpo=31809]: Add tests to verify connection with secp ECDH curves.

Build

bpo-32898 [https://bugs.python.org/issue?@action=redirect&bpo=32898]: Fix the python debug build when using COUNT_ALLOCS.

Windows

bpo-32901 [https://bugs.python.org/issue?@action=redirect&bpo=32901]: Update Tcl and Tk versions to 8.6.8

bpo-31966 [https://bugs.python.org/issue?@action=redirect&bpo=31966]: Fixed WindowsConsoleIO.write() for writing empty data.

bpo-32409 [https://bugs.python.org/issue?@action=redirect&bpo=32409]: Ensures activate.bat can handle Unicode contents.

bpo-32457 [https://bugs.python.org/issue?@action=redirect&bpo=32457]: Improves handling of denormalized executable path when launching Python.

bpo-32370 [https://bugs.python.org/issue?@action=redirect&bpo=32370]: Use the correct encoding for ipconfig output in the uuid module. Patch by Segev Finer.

bpo-29248 [https://bugs.python.org/issue?@action=redirect&bpo=29248]: Fix os.readlink() on Windows, which was mistakenly treating the PrintNameOffset field of the reparse data buffer as a number of characters instead of bytes. Patch by Craig Holmquist and SSE4.

macOS

bpo-32901 [https://bugs.python.org/issue?@action=redirect&bpo=32901]: Update macOS 10.9+ installer to Tcl/Tk 8.6.8.

IDLE

bpo-32916 [https://bugs.python.org/issue?@action=redirect&bpo=32916]: Change str to code in pyparse.

bpo-32905 [https://bugs.python.org/issue?@action=redirect&bpo=32905]: Remove unused code in pyparse module.

bpo-32874 [https://bugs.python.org/issue?@action=redirect&bpo=32874]: Add tests for pyparse.

bpo-32837 [https://bugs.python.org/issue?@action=redirect&bpo=32837]: Using the system and place-dependent default encoding for open() is a bad idea for IDLE’s system and location-independent files.

bpo-32826 [https://bugs.python.org/issue?@action=redirect&bpo=32826]: Add “encoding=utf-8” to open() in IDLE’s test_help_about. GUI test test_file_buttons() only looks at initial ascii-only lines, but failed on systems where open() defaults to ‘ascii’ because readline() internally reads and decodes far enough ahead to encounter a non-ascii character in CREDITS.txt.

bpo-32765 [https://bugs.python.org/issue?@action=redirect&bpo=32765]: Update configdialog General tab docstring to add new widgets to the widget list.

Tools/Demos

bpo-32222 [https://bugs.python.org/issue?@action=redirect&bpo=32222]: Fix pygettext not extracting docstrings for functions with type annotated arguments. Patch by Toby Harradine.

Python 3.7.0 beta 1

Release date: 2018-01-30

Core and Builtins

bpo-32703 [https://bugs.python.org/issue?@action=redirect&bpo=32703]: Fix coroutine’s ResourceWarning when there’s an active error set when it’s being finalized.

bpo-32650 [https://bugs.python.org/issue?@action=redirect&bpo=32650]: Pdb and other debuggers dependent on bdb.py will correctly step over (next command) native coroutines. Patch by Pablo Galindo.

bpo-28685 [https://bugs.python.org/issue?@action=redirect&bpo=28685]: Optimize list.sort() and sorted() by using type specialized comparisons when possible.

bpo-32685 [https://bugs.python.org/issue?@action=redirect&bpo=32685]: Improve suggestion when the Python 2 form of print statement is either present on the same line as the header of a compound statement or else terminated by a semi-colon instead of a newline. Patch by Nitish Chandra.

bpo-32697 [https://bugs.python.org/issue?@action=redirect&bpo=32697]: Python now explicitly preserves the definition order of keyword-only parameters. It’s always preserved their order, but this behavior was never guaranteed before; this behavior is now guaranteed and tested.

bpo-32690 [https://bugs.python.org/issue?@action=redirect&bpo=32690]: The locals() dictionary now displays in the lexical order that variables were defined. Previously, the order was reversed.

bpo-32677 [https://bugs.python.org/issue?@action=redirect&bpo=32677]: Add .isascii() method to str, bytes and bytearray. It can be used to test that string contains only ASCII characters.

bpo-32670 [https://bugs.python.org/issue?@action=redirect&bpo=32670]: Enforce PEP 479 [https://peps.python.org/pep-0479/] for all code. This means that manually raising a StopIteration exception from a generator is prohibited for all code, regardless of whether ‘from __future__ import generator_stop’ was used or not.

bpo-32591 [https://bugs.python.org/issue?@action=redirect&bpo=32591]: Added built-in support for tracking the origin of coroutine objects; see sys.set_coroutine_origin_tracking_depth and CoroutineType.cr_origin. This replaces the asyncio debug mode’s use of coroutine wrapping for native coroutine objects.

bpo-31368 [https://bugs.python.org/issue?@action=redirect&bpo=31368]: Expose preadv and pwritev system calls in the os module. Patch by Pablo Galindo

bpo-32544 [https://bugs.python.org/issue?@action=redirect&bpo=32544]: hasattr(obj, name) and getattr(obj, name, default) are about 4 times faster than before when name is not found and obj doesn’t override __getattr__ or __getattribute__.

bpo-26163 [https://bugs.python.org/issue?@action=redirect&bpo=26163]: Improved frozenset() hash to create more distinct hash values when faced with datasets containing many similar values.

bpo-32550 [https://bugs.python.org/issue?@action=redirect&bpo=32550]: Remove the STORE_ANNOTATION bytecode.

bpo-20104 [https://bugs.python.org/issue?@action=redirect&bpo=20104]: Expose posix_spawn as a low level API in the os module. (removed before 3.7.0rc1)

bpo-24340 [https://bugs.python.org/issue?@action=redirect&bpo=24340]: Fixed estimation of the code stack size.

bpo-32436 [https://bugs.python.org/issue?@action=redirect&bpo=32436]: Implement PEP 567 [https://peps.python.org/pep-0567/] Context Variables.

bpo-18533 [https://bugs.python.org/issue?@action=redirect&bpo=18533]: repr() on a dict containing its own values() or items() no longer raises RecursionError; OrderedDict similarly. Instead, use ..., as for other recursive structures. Patch by Ben North.

bpo-20891 [https://bugs.python.org/issue?@action=redirect&bpo=20891]: Py_Initialize() now creates the GIL. The GIL is no longer created “on demand” to fix a race condition when PyGILState_Ensure() is called in a non-Python thread.

bpo-32028 [https://bugs.python.org/issue?@action=redirect&bpo=32028]: Leading whitespace is now correctly ignored when generating suggestions for converting Py2 print statements to Py3 builtin print function calls. Patch by Sanyam Khurana.

bpo-31179 [https://bugs.python.org/issue?@action=redirect&bpo=31179]: Make dict.copy() up to 5.5 times faster.

bpo-31113 [https://bugs.python.org/issue?@action=redirect&bpo=31113]: Get rid of recursion in the compiler for normal control flow.

Library

bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988]: Deprecate exposing the contents of collections.abc in the regular collections module.

bpo-31429 [https://bugs.python.org/issue?@action=redirect&bpo=31429]: The default cipher suite selection of the ssl module now uses a blacklist approach rather than a hard-coded whitelist. Python no longer re-enables ciphers that have been blocked by OpenSSL security update. Default cipher suite selection can be configured on compile time.

bpo-30306 [https://bugs.python.org/issue?@action=redirect&bpo=30306]: contextlib.contextmanager now releases the arguments passed to the underlying generator as soon as the context manager is entered. Previously it would keep them alive for as long as the context manager was alive, even when not being used as a function decorator. Patch by Martin Teichmann.

bpo-21417 [https://bugs.python.org/issue?@action=redirect&bpo=21417]: Added support for setting the compression level for zipfile.ZipFile.

bpo-32251 [https://bugs.python.org/issue?@action=redirect&bpo=32251]: Implement asyncio.BufferedProtocol (provisional API).

bpo-32513 [https://bugs.python.org/issue?@action=redirect&bpo=32513]: In dataclasses, allow easier overriding of dunder methods without specifying decorator parameters.

bpo-32660 [https://bugs.python.org/issue?@action=redirect&bpo=32660]: termios makes available FIONREAD, FIONCLEX, FIOCLEX, FIOASYNC and FIONBIO also under Solaris/derivatives.

bpo-27931 [https://bugs.python.org/issue?@action=redirect&bpo=27931]: Fix email address header parsing error when the username is an empty quoted string. Patch by Xiang Zhang.

bpo-32659 [https://bugs.python.org/issue?@action=redirect&bpo=32659]: Under Solaris and derivatives, os.stat_result provides a st_fstype attribute.

bpo-32662 [https://bugs.python.org/issue?@action=redirect&bpo=32662]: Implement Server.start_serving(), Server.serve_forever(), and Server.is_serving() methods. Add ‘start_serving’ keyword parameter to loop.create_server() and loop.create_unix_server().

bpo-32391 [https://bugs.python.org/issue?@action=redirect&bpo=32391]: Implement asyncio.StreamWriter.wait_closed() and asyncio.StreamWriter.is_closing() methods

bpo-32643 [https://bugs.python.org/issue?@action=redirect&bpo=32643]: Make Task._step, Task._wakeup and Future._schedule_callbacks methods private.

bpo-32630 [https://bugs.python.org/issue?@action=redirect&bpo=32630]: Refactor decimal module to use contextvars to store decimal context.

bpo-32622 [https://bugs.python.org/issue?@action=redirect&bpo=32622]: Add asyncio.AbstractEventLoop.sendfile() method.

bpo-32304 [https://bugs.python.org/issue?@action=redirect&bpo=32304]: distutils’ upload command no longer corrupts tar files ending with a CR byte, and no longer tries to convert CR to CRLF in any of the upload text fields.

bpo-32502 [https://bugs.python.org/issue?@action=redirect&bpo=32502]: uuid.uuid1 no longer raises an exception if a 64-bit hardware address is encountered.

bpo-32596 [https://bugs.python.org/issue?@action=redirect&bpo=32596]: concurrent.futures imports ThreadPoolExecutor and ProcessPoolExecutor lazily (using PEP 562 [https://peps.python.org/pep-0562/]). It makes import asyncio about 15% faster because asyncio uses only ThreadPoolExecutor by default.

bpo-31801 [https://bugs.python.org/issue?@action=redirect&bpo=31801]: Add _ignore_ to Enum so temporary variables can be used during class construction without being turned into members.

bpo-32576 [https://bugs.python.org/issue?@action=redirect&bpo=32576]: Use queue.SimpleQueue() in places where it can be invoked from a weakref callback.

bpo-32574 [https://bugs.python.org/issue?@action=redirect&bpo=32574]: Fix memory leak in asyncio.Queue, when the queue has limited size and it is full, the cancellation of queue.put() can cause a memory leak. Patch by: José Melero.

bpo-32521 [https://bugs.python.org/issue?@action=redirect&bpo=32521]: The nis module is now compatible with new libnsl and headers location.

bpo-32467 [https://bugs.python.org/issue?@action=redirect&bpo=32467]: collections.abc.ValuesView now inherits from collections.abc.Collection.

bpo-32473 [https://bugs.python.org/issue?@action=redirect&bpo=32473]: Improve ABCMeta._dump_registry() output readability

bpo-32102 [https://bugs.python.org/issue?@action=redirect&bpo=32102]: New argument capture_output for subprocess.run

bpo-32521 [https://bugs.python.org/issue?@action=redirect&bpo=32521]: glibc has removed Sun RPC. Use replacement libtirpc headers and library in nis module.

bpo-32493 [https://bugs.python.org/issue?@action=redirect&bpo=32493]: UUID module fixes build for FreeBSD/OpenBSD

bpo-32503 [https://bugs.python.org/issue?@action=redirect&bpo=32503]: Pickling with protocol 4 no longer creates too small frames.

bpo-29237 [https://bugs.python.org/issue?@action=redirect&bpo=29237]: Create enum for pstats sorting options

bpo-32454 [https://bugs.python.org/issue?@action=redirect&bpo=32454]: Add close(fd) function to the socket module.

bpo-25942 [https://bugs.python.org/issue?@action=redirect&bpo=25942]: The subprocess module is now more graceful when handling a Ctrl-C KeyboardInterrupt during subprocess.call, subprocess.run, or a Popen context manager. It now waits a short amount of time for the child (presumed to have also gotten the SIGINT) to exit, before continuing the KeyboardInterrupt exception handling. This still includes a SIGKILL in the call() and run() APIs, but at least the child had a chance first.

bpo-32433 [https://bugs.python.org/issue?@action=redirect&bpo=32433]: The hmac module now has hmac.digest(), which provides an optimized HMAC digest.

bpo-28134 [https://bugs.python.org/issue?@action=redirect&bpo=28134]: Sockets now auto-detect family, type and protocol from file descriptor by default.

bpo-32404 [https://bugs.python.org/issue?@action=redirect&bpo=32404]: Fix bug where datetime.datetime.fromtimestamp() did not call __new__ in datetime.datetime subclasses.

bpo-32403 [https://bugs.python.org/issue?@action=redirect&bpo=32403]: Improved speed of datetime.date and datetime.datetime alternate constructors.

bpo-32228 [https://bugs.python.org/issue?@action=redirect&bpo=32228]: Ensure that truncate() preserves the file position (as reported by tell()) after writes longer than the buffer size.

bpo-32410 [https://bugs.python.org/issue?@action=redirect&bpo=32410]: Implement loop.sock_sendfile for asyncio event loop.

bpo-22908 [https://bugs.python.org/issue?@action=redirect&bpo=22908]: Added seek and tell to the ZipExtFile class. This only works if the file object used to open the zipfile is seekable.

bpo-32373 [https://bugs.python.org/issue?@action=redirect&bpo=32373]: Add socket.getblocking() method.

bpo-32248 [https://bugs.python.org/issue?@action=redirect&bpo=32248]: Add importlib.resources and importlib.abc.ResourceReader as the unified API for reading resources contained within packages. Loaders wishing to support resource reading must implement the get_resource_reader() method. File-based and zipimport-based loaders both implement these APIs. importlib.abc.ResourceLoader is deprecated in favor of these new APIs.

bpo-32320 [https://bugs.python.org/issue?@action=redirect&bpo=32320]: collections.namedtuple() now supports default values.

bpo-29302 [https://bugs.python.org/issue?@action=redirect&bpo=29302]: Add contextlib.AsyncExitStack. Patch by Alexander Mohr and Ilya Kulakov.

bpo-31961 [https://bugs.python.org/issue?@action=redirect&bpo=31961]: Removed in Python 3.7.0b2. The args argument of subprocess.Popen can now be a path-like object. If args is given as a sequence, it’s first element can now be a path-like object as well.

bpo-31900 [https://bugs.python.org/issue?@action=redirect&bpo=31900]: The locale.localeconv() function now sets temporarily the LC_CTYPE locale to the LC_NUMERIC locale to decode decimal_point and thousands_sep byte strings if they are non-ASCII or longer than 1 byte, and the LC_NUMERIC locale is different than the LC_CTYPE locale. This temporary change affects other threads. Same change for the str.format() method when formatting a number (int, float, float and subclasses) with the n type (ex: '{:n}'.format(1234)).

bpo-31853 [https://bugs.python.org/issue?@action=redirect&bpo=31853]: Use super().method instead of socket.method in SSLSocket. They were there most likely for legacy reasons.

bpo-31399 [https://bugs.python.org/issue?@action=redirect&bpo=31399]: The ssl module now uses OpenSSL’s X509_VERIFY_PARAM_set1_host() and X509_VERIFY_PARAM_set1_ip() API to verify hostname and IP addresses. Subject common name fallback can be disabled with SSLContext.hostname_checks_common_name.

bpo-14976 [https://bugs.python.org/issue?@action=redirect&bpo=14976]: Add a queue.SimpleQueue class, an unbounded FIFO queue with a reentrant C implementation of put().

Documentation

bpo-32724 [https://bugs.python.org/issue?@action=redirect&bpo=32724]: Add references to some commands in the documentation of Pdb. Patch by Stéphane Wirtel

bpo-32649 [https://bugs.python.org/issue?@action=redirect&bpo=32649]: Complete the C API documentation, profiling and tracing part with the newly added per-opcode events.

bpo-17799 [https://bugs.python.org/issue?@action=redirect&bpo=17799]: Explain real behaviour of sys.settrace and sys.setprofile and their C-API counterparts regarding which type of events are received in each function. Patch by Pablo Galindo Salgado.

Tests

bpo-32721 [https://bugs.python.org/issue?@action=redirect&bpo=32721]: Fix test_hashlib to not fail if the _md5 module is not built.

bpo-28414 [https://bugs.python.org/issue?@action=redirect&bpo=28414]: Add test cases for IDNA 2003 and 2008 host names. IDNA 2003 internationalized host names are working since bpo-31399 [https://bugs.python.org/issue?@action=redirect&bpo=31399] has landed. IDNA 2008 are still broken.

bpo-32604 [https://bugs.python.org/issue?@action=redirect&bpo=32604]: Add a new “_xxsubinterpreters” extension module that exposes the existing subinterpreter C-API and a new cross-interpreter data sharing mechanism. The module is primarily intended for more thorough testing of the existing subinterpreter support. Note that the _xxsubinterpreters module has been removed in 3.7.0rc1.

bpo-32602 [https://bugs.python.org/issue?@action=redirect&bpo=32602]: Add test certs and test for ECDSA cert and EC/RSA dual mode.

bpo-32549 [https://bugs.python.org/issue?@action=redirect&bpo=32549]: On Travis CI, Python now Compiles and uses a local copy of OpenSSL 1.1.0g for testing.

Build

bpo-32635 [https://bugs.python.org/issue?@action=redirect&bpo=32635]: Fix segfault of the crypt module when libxcrypt is provided instead of libcrypt at the system.

bpo-32598 [https://bugs.python.org/issue?@action=redirect&bpo=32598]: Use autoconf to detect OpenSSL libs, headers and supported features. The ax_check_openssl M4 macro uses pkg-config to locate OpenSSL and falls back to manual search.

bpo-32593 [https://bugs.python.org/issue?@action=redirect&bpo=32593]: Drop support of FreeBSD 9 and older.

bpo-29708 [https://bugs.python.org/issue?@action=redirect&bpo=29708]: If the SOURCE_DATE_EPOCH environment variable is set, py_compile will always create hash-based .pyc files.

Windows

bpo-32588 [https://bugs.python.org/issue?@action=redirect&bpo=32588]: Create standalone _distutils_findvs module and add missing _queue module to installer.

bpo-29911 [https://bugs.python.org/issue?@action=redirect&bpo=29911]: Ensure separate Modify and Uninstall buttons are displayed.

bpo-32507 [https://bugs.python.org/issue?@action=redirect&bpo=32507]: Use app-local UCRT install rather than the proper update for old versions of Windows.

macOS

bpo-32726 [https://bugs.python.org/issue?@action=redirect&bpo=32726]: Provide an additional, more modern macOS installer variant that supports macOS 10.9+ systems in 64-bit mode only. Upgrade the supplied third-party libraries to OpenSSL 1.1.0g and to SQLite 3.22.0. The 10.9+ installer now links with and supplies its own copy of Tcl/Tk 8.6.

bpo-28440 [https://bugs.python.org/issue?@action=redirect&bpo=28440]: No longer add /Library/Python/3.x/site-packages to sys.path for macOS framework builds to avoid future conflicts.

C API

bpo-32681 [https://bugs.python.org/issue?@action=redirect&bpo=32681]: Fix uninitialized variable ‘res’ in the C implementation of os.dup2. Patch by Stéphane Wirtel

bpo-10381 [https://bugs.python.org/issue?@action=redirect&bpo=10381]: Add C API access to the datetime.timezone constructor and datetime.timezone.UTC singleton.

Python 3.7.0 alpha 4

Release date: 2018-01-08

Core and Builtins

bpo-31975 [https://bugs.python.org/issue?@action=redirect&bpo=31975]: The default warning filter list now starts with a “default::DeprecationWarning:__main__” entry, so deprecation warnings are once again shown by default in single-file scripts and at the interactive prompt.

bpo-32226 [https://bugs.python.org/issue?@action=redirect&bpo=32226]: __class_getitem__ is now an automatic class method.

bpo-32399 [https://bugs.python.org/issue?@action=redirect&bpo=32399]: Add AIX uuid library support for RFC4122 using uuid_create() in libc.a

bpo-32390 [https://bugs.python.org/issue?@action=redirect&bpo=32390]: Fix the compilation failure on AIX after the f_fsid field has been added to the object returned by os.statvfs() (bpo-32143 [https://bugs.python.org/issue?@action=redirect&bpo=32143]). Original patch by Michael Felt.

bpo-32379 [https://bugs.python.org/issue?@action=redirect&bpo=32379]: Make MRO computation faster when a class inherits from a single base.

bpo-32259 [https://bugs.python.org/issue?@action=redirect&bpo=32259]: The error message of a TypeError raised when unpack non-iterable is now more specific.

bpo-27169 [https://bugs.python.org/issue?@action=redirect&bpo=27169]: The __debug__ constant is now optimized out at compile time. This fixes also bpo-22091 [https://bugs.python.org/issue?@action=redirect&bpo=22091].

bpo-32329 [https://bugs.python.org/issue?@action=redirect&bpo=32329]: The -R option now turns on hash randomization when the PYTHONHASHSEED environment variable is set to 0. Previously, the option was ignored. Moreover, sys.flags.hash_randomization is now properly set to 0 when hash randomization is turned off by PYTHONHASHSEED=0.

bpo-30416 [https://bugs.python.org/issue?@action=redirect&bpo=30416]: The optimizer is now protected from spending much time doing complex calculations and consuming much memory for creating large constants in constant folding. Increased limits for constants that can be produced in constant folding.

bpo-32282 [https://bugs.python.org/issue?@action=redirect&bpo=32282]: Fix an unnecessary ifdef in the include of VersionHelpers.h in socketmodule on Windows.

bpo-30579 [https://bugs.python.org/issue?@action=redirect&bpo=30579]: Implement TracebackType.__new__ to allow Python-level creation of traceback objects, and make TracebackType.tb_next mutable.

bpo-32260 [https://bugs.python.org/issue?@action=redirect&bpo=32260]: Don’t byte swap the input keys to the SipHash algorithm on big-endian platforms. This should ensure siphash gives consistent results across platforms.

bpo-31506 [https://bugs.python.org/issue?@action=redirect&bpo=31506]: Improve the error message logic for object.__new__ and object.__init__. Patch by Sanyam Khurana.

bpo-20361 [https://bugs.python.org/issue?@action=redirect&bpo=20361]: -b and -bb now inject 'default::BytesWarning' and error::BytesWarning entries into sys.warnoptions, ensuring that they take precedence over any other warning filters configured via the -W option or the PYTHONWARNINGS environment variable.

bpo-32230 [https://bugs.python.org/issue?@action=redirect&bpo=32230]: -X dev now injects a 'default' entry into sys.warnoptions, ensuring that it behaves identically to actually passing -Wdefault at the command line.

bpo-29240 [https://bugs.python.org/issue?@action=redirect&bpo=29240]: Add a new UTF-8 mode: implementation of the PEP 540 [https://peps.python.org/pep-0540/].

bpo-32226 [https://bugs.python.org/issue?@action=redirect&bpo=32226]: PEP 560 [https://peps.python.org/pep-0560/]: Add support for __mro_entries__ and __class_getitem__. Implemented by Ivan Levkivskyi.

bpo-32225 [https://bugs.python.org/issue?@action=redirect&bpo=32225]: PEP 562 [https://peps.python.org/pep-0562/]: Add support for module __getattr__ and __dir__. Implemented by Ivan Levkivskyi.

bpo-31901 [https://bugs.python.org/issue?@action=redirect&bpo=31901]: The atexit module now has its callback stored per interpreter.

bpo-31650 [https://bugs.python.org/issue?@action=redirect&bpo=31650]: Implement PEP 552 [https://peps.python.org/pep-0552/] (Deterministic pycs). Python now supports invalidating bytecode cache files bashed on a source content hash rather than source last-modified time.

bpo-29469 [https://bugs.python.org/issue?@action=redirect&bpo=29469]: Move constant folding from bytecode layer to AST layer. Original patch by Eugene Toder.

Library

bpo-32506 [https://bugs.python.org/issue?@action=redirect&bpo=32506]: Now that dict is defined as keeping insertion order, drop OrderedDict and just use plain dict.

bpo-32279 [https://bugs.python.org/issue?@action=redirect&bpo=32279]: Add params to dataclasses.make_dataclasses(): init, repr, eq, order, hash, and frozen. Pass them through to dataclass().

bpo-32278 [https://bugs.python.org/issue?@action=redirect&bpo=32278]: Make type information optional on dataclasses.make_dataclass(). If omitted, the string ‘typing.Any’ is used.

bpo-32499 [https://bugs.python.org/issue?@action=redirect&bpo=32499]: Add dataclasses.is_dataclass(obj), which returns True if obj is a dataclass or an instance of one.

bpo-32468 [https://bugs.python.org/issue?@action=redirect&bpo=32468]: Improve frame repr() to mention filename, code name and current line number.

bpo-23749 [https://bugs.python.org/issue?@action=redirect&bpo=23749]: asyncio: Implement loop.start_tls()

bpo-32441 [https://bugs.python.org/issue?@action=redirect&bpo=32441]: Return the new file descriptor (i.e., the second argument) from os.dup2. Previously, None was always returned.

bpo-32422 [https://bugs.python.org/issue?@action=redirect&bpo=32422]: functools.lru_cache uses less memory (3 words for each cached key) and takes about 1/3 time for cyclic GC.

bpo-31721 [https://bugs.python.org/issue?@action=redirect&bpo=31721]: Prevent Python crash from happening when Future._log_traceback is set to True manually. Now it can only be set to False, or a ValueError is raised.

bpo-32415 [https://bugs.python.org/issue?@action=redirect&bpo=32415]: asyncio: Add Task.get_loop() and Future.get_loop()

bpo-26133 [https://bugs.python.org/issue?@action=redirect&bpo=26133]: Don’t unsubscribe signals in asyncio UNIX event loop on interpreter shutdown.

bpo-32363 [https://bugs.python.org/issue?@action=redirect&bpo=32363]: Make asyncio.Task.set_exception() and set_result() raise NotImplementedError. Task._step() and Future.__await__() raise proper exceptions when they are in an invalid state, instead of raising an AssertionError.

bpo-32357 [https://bugs.python.org/issue?@action=redirect&bpo=32357]: Optimize asyncio.iscoroutine() and loop.create_task() for non-native coroutines (e.g. async/await compiled with Cython). ‘loop.create_task(python_coroutine)’ used to be 20% faster than ‘loop.create_task(cython_coroutine)’. Now, the latter is as fast.

bpo-32356 [https://bugs.python.org/issue?@action=redirect&bpo=32356]: asyncio.transport.resume_reading() and pause_reading() are now idempotent. New transport.is_reading() method is added.

bpo-32355 [https://bugs.python.org/issue?@action=redirect&bpo=32355]: Optimize asyncio.gather(); now up to 15% faster.

bpo-32351 [https://bugs.python.org/issue?@action=redirect&bpo=32351]: Use fastpath in asyncio.sleep if delay<0 (2x boost)

bpo-32348 [https://bugs.python.org/issue?@action=redirect&bpo=32348]: Optimize asyncio.Future schedule/add/remove callback. The optimization shows 3-6% performance improvements of async/await code.

bpo-32331 [https://bugs.python.org/issue?@action=redirect&bpo=32331]: Fix socket.settimeout() and socket.setblocking() to keep socket.type as is. Fix socket.socket() constructor to reset any bit flags applied to socket’s type. This change only affects OSes that have SOCK_NONBLOCK and/or SOCK_CLOEXEC.

bpo-32248 [https://bugs.python.org/issue?@action=redirect&bpo=32248]: Add importlib.abc.ResourceReader as an ABC for loaders to provide a unified API for reading resources contained within packages. Also add importlib.resources as the port of importlib_resources.

bpo-32311 [https://bugs.python.org/issue?@action=redirect&bpo=32311]: Implement asyncio.create_task(coro) shortcut

bpo-32327 [https://bugs.python.org/issue?@action=redirect&bpo=32327]: Convert asyncio functions that were documented as coroutines to coroutines. Affected functions: loop.sock_sendall, loop.sock_recv, loop.sock_accept, loop.getaddrinfo, loop.getnameinfo.

bpo-32323 [https://bugs.python.org/issue?@action=redirect&bpo=32323]: urllib.parse.urlsplit() does not convert zone-id (scope) to lower case for scoped IPv6 addresses in hostnames now.

bpo-32302 [https://bugs.python.org/issue?@action=redirect&bpo=32302]: Fix bdist_wininst of distutils for CRT v142: it binary compatible with CRT v140.

bpo-29711 [https://bugs.python.org/issue?@action=redirect&bpo=29711]: Fix stop_serving in asyncio proactor loop kill all listening servers

bpo-32308 [https://bugs.python.org/issue?@action=redirect&bpo=32308]: re.sub() now replaces empty matches adjacent to a previous non-empty match.

bpo-29970 [https://bugs.python.org/issue?@action=redirect&bpo=29970]: Abort asyncio SSLProtocol connection if handshake not complete within 10 seconds.

bpo-32314 [https://bugs.python.org/issue?@action=redirect&bpo=32314]: Implement asyncio.run().

bpo-17852 [https://bugs.python.org/issue?@action=redirect&bpo=17852]: Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics.

bpo-32296 [https://bugs.python.org/issue?@action=redirect&bpo=32296]: Implement asyncio._get_running_loop() and get_event_loop() in C. This makes them 4x faster.

bpo-32250 [https://bugs.python.org/issue?@action=redirect&bpo=32250]: Implement asyncio.current_task() and asyncio.all_tasks(). Add helpers intended to be used by alternative task implementations: asyncio._register_task, asyncio._enter_task, asyncio._leave_task and asyncio._unregister_task. Deprecate asyncio.Task.current_task() and asyncio.Task.all_tasks().

bpo-32255 [https://bugs.python.org/issue?@action=redirect&bpo=32255]: A single empty field is now always quoted when written into a CSV file. This allows to distinguish an empty row from a row consisting of a single empty field. Patch by Licht Takeuchi.

bpo-32277 [https://bugs.python.org/issue?@action=redirect&bpo=32277]: Raise NotImplementedError instead of SystemError on platforms where chmod(..., follow_symlinks=False) is not supported. Patch by Anthony Sottile.

bpo-30050 [https://bugs.python.org/issue?@action=redirect&bpo=30050]: New argument warn_on_full_buffer to signal.set_wakeup_fd lets you control whether Python prints a warning on stderr when the wakeup fd buffer overflows.

bpo-29137 [https://bugs.python.org/issue?@action=redirect&bpo=29137]: The fpectl library has been removed. It was never enabled by default, never worked correctly on x86-64, and it changed the Python ABI in ways that caused unexpected breakage of C extensions.

bpo-32273 [https://bugs.python.org/issue?@action=redirect&bpo=32273]: Move asyncio.test_utils to test.test_asyncio.

bpo-32272 [https://bugs.python.org/issue?@action=redirect&bpo=32272]: Remove asyncio.async() function.

bpo-32269 [https://bugs.python.org/issue?@action=redirect&bpo=32269]: Add asyncio.get_running_loop() function.

bpo-32265 [https://bugs.python.org/issue?@action=redirect&bpo=32265]: All class and static methods of builtin types now are correctly classified by inspect.classify_class_attrs() and grouped in pydoc output. Added types.ClassMethodDescriptorType for unbound class methods of builtin types.

bpo-32253 [https://bugs.python.org/issue?@action=redirect&bpo=32253]: Deprecate yield from lock, await lock, with (yield from lock) and with await lock for asyncio synchronization primitives.

bpo-22589 [https://bugs.python.org/issue?@action=redirect&bpo=22589]: Changed MIME type of .bmp from ‘image/x-ms-bmp’ to ‘image/bmp’

bpo-32193 [https://bugs.python.org/issue?@action=redirect&bpo=32193]: Convert asyncio to use async/await syntax. Old styled yield from is still supported too.

bpo-32206 [https://bugs.python.org/issue?@action=redirect&bpo=32206]: Add support to run modules with pdb

bpo-32227 [https://bugs.python.org/issue?@action=redirect&bpo=32227]: functools.singledispatch now supports registering implementations using type annotations.

bpo-15873 [https://bugs.python.org/issue?@action=redirect&bpo=15873]: Added new alternate constructors datetime.datetime.fromisoformat(), datetime.time.fromisoformat() and datetime.date.fromisoformat() as the inverse operation of each classes’s respective isoformat methods.

bpo-32199 [https://bugs.python.org/issue?@action=redirect&bpo=32199]: The getnode() ip getter now uses ‘ip link’ instead of ‘ip link list’.

bpo-32143 [https://bugs.python.org/issue?@action=redirect&bpo=32143]: os.statvfs() includes the f_fsid field from statvfs(2)

bpo-26439 [https://bugs.python.org/issue?@action=redirect&bpo=26439]: Fix ctypes.util.find_library() for AIX by implementing ctypes._aix.find_library() Patch by: Michael Felt

bpo-31993 [https://bugs.python.org/issue?@action=redirect&bpo=31993]: The pickler now uses less memory when serializing large bytes and str objects into a file. Pickles created with protocol 4 will require less memory for unpickling large bytes and str objects.

bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456]: Ensure TCP_NODELAY is set on Linux. Tests by Victor Stinner.

bpo-31778 [https://bugs.python.org/issue?@action=redirect&bpo=31778]: ast.literal_eval() is now more strict. Addition and subtraction of arbitrary numbers no longer allowed.

bpo-31802 [https://bugs.python.org/issue?@action=redirect&bpo=31802]: Importing native path module (posixpath, ntpath) now works even if the os module still is not imported.

bpo-30241 [https://bugs.python.org/issue?@action=redirect&bpo=30241]: Add contextlib.AbstractAsyncContextManager. Patch by Jelle Zijlstra.

bpo-31699 [https://bugs.python.org/issue?@action=redirect&bpo=31699]: Fix deadlocks in concurrent.futures.ProcessPoolExecutor when task arguments or results cause pickling or unpickling errors. This should make sure that calls to the ProcessPoolExecutor API always eventually return.

bpo-15216 [https://bugs.python.org/issue?@action=redirect&bpo=15216]: TextIOWrapper.reconfigure() supports changing encoding, errors, and newline.

Documentation

bpo-32418 [https://bugs.python.org/issue?@action=redirect&bpo=32418]: Add get_loop() method to Server and AbstractServer classes.

Tests

bpo-32252 [https://bugs.python.org/issue?@action=redirect&bpo=32252]: Fix faulthandler_suppress_crash_report() used to prevent core dump files when testing crashes. getrlimit() returns zero on success.

bpo-32002 [https://bugs.python.org/issue?@action=redirect&bpo=32002]: Adjust C locale coercion testing for the empty locale and POSIX locale cases to more readily adjust to platform dependent behaviour.

Windows

bpo-19764 [https://bugs.python.org/issue?@action=redirect&bpo=19764]: Implement support for subprocess.Popen(close_fds=True) on Windows. Patch by Segev Finer.

Tools/Demos

bpo-24960 [https://bugs.python.org/issue?@action=redirect&bpo=24960]: 2to3 and lib2to3 can now read pickled grammar files using pkgutil.get_data() rather than probing the filesystem. This lets 2to3 and lib2to3 work when run from a zipfile.

C API

bpo-32030 [https://bugs.python.org/issue?@action=redirect&bpo=32030]: Py_Initialize() doesn’t reset the memory allocators to default if the PYTHONMALLOC environment variable is not set.

bpo-29084 [https://bugs.python.org/issue?@action=redirect&bpo=29084]: Undocumented C API for OrderedDict has been excluded from the limited C API. It was added by mistake and actually never worked in the limited C API.

bpo-32264 [https://bugs.python.org/issue?@action=redirect&bpo=32264]: Moved the pygetopt.h header into internal/, since it has no public APIs.

bpo-32241 [https://bugs.python.org/issue?@action=redirect&bpo=32241]: Py_SetProgramName() and Py_SetPythonHome() now take the const wchar * arguments instead of wchar *.

Python 3.7.0 alpha 3

Release date: 2017-12-05

Core and Builtins

bpo-32176 [https://bugs.python.org/issue?@action=redirect&bpo=32176]: co_flags.CO_NOFREE is now always set correctly by the code object constructor based on freevars and cellvars, rather than needing to be set correctly by the caller. This ensures it will be cleared automatically when additional cell references are injected into a modified code object and function.

bpo-10544 [https://bugs.python.org/issue?@action=redirect&bpo=10544]: Yield expressions are now deprecated in comprehensions and generator expressions. They are still permitted in the definition of the outermost iterable, as that is evaluated directly in the enclosing scope.

bpo-32137 [https://bugs.python.org/issue?@action=redirect&bpo=32137]: The repr of deeply nested dict now raises a RecursionError instead of crashing due to a stack overflow.

bpo-32096 [https://bugs.python.org/issue?@action=redirect&bpo=32096]: Revert memory allocator changes in the C API: move structures back from _PyRuntime to Objects/obmalloc.c. The memory allocators are once again initialized statically, and so PyMem_RawMalloc() and Py_DecodeLocale() can be called before _PyRuntime_Initialize().

bpo-32043 [https://bugs.python.org/issue?@action=redirect&bpo=32043]: Add a new “developer mode”: new “-X dev” command line option to enable debug checks at runtime.

bpo-32023 [https://bugs.python.org/issue?@action=redirect&bpo=32023]: SyntaxError is now correctly raised when a generator expression without parenthesis is used instead of an inheritance list in a class definition. The duplication of the parentheses can be omitted only on calls.

bpo-32012 [https://bugs.python.org/issue?@action=redirect&bpo=32012]: SyntaxError is now correctly raised when a generator expression without parenthesis is passed as an argument, but followed by a trailing comma. A generator expression always needs to be directly inside a set of parentheses and cannot have a comma on either side.

bpo-28180 [https://bugs.python.org/issue?@action=redirect&bpo=28180]: A new internal _Py_SetLocaleFromEnv(category) helper function has been added in order to improve the consistency of behaviour across different libc implementations (e.g. Android doesn’t support setting the locale from the environment by default).

bpo-31949 [https://bugs.python.org/issue?@action=redirect&bpo=31949]: Fixed several issues in printing tracebacks (PyTraceBack_Print()). Setting sys.tracebacklimit to 0 or less now suppresses printing tracebacks. Setting sys.tracebacklimit to None now causes using the default limit. Setting sys.tracebacklimit to an integer larger than LONG_MAX now means using the limit LONG_MAX rather than the default limit. Fixed integer overflows in the case of more than 2**31 traceback items on Windows. Fixed output errors handling.

bpo-30696 [https://bugs.python.org/issue?@action=redirect&bpo=30696]: Fix the interactive interpreter looping endlessly when no memory.

bpo-20047 [https://bugs.python.org/issue?@action=redirect&bpo=20047]: Bytearray methods partition() and rpartition() now accept only bytes-like objects as separator, as documented. In particular they now raise TypeError rather of returning a bogus result when an integer is passed as a separator.

bpo-21720 [https://bugs.python.org/issue?@action=redirect&bpo=21720]: BytesWarning no longer emitted when the fromlist argument of __import__() or the __all__ attribute of the module contain bytes instances.

bpo-31845 [https://bugs.python.org/issue?@action=redirect&bpo=31845]: Environment variables are once more read correctly at interpreter startup.

bpo-28936 [https://bugs.python.org/issue?@action=redirect&bpo=28936]: Ensure that lexically first syntax error involving a parameter and global or nonlocal is detected first at a given scope. Patch by Ivan Levkivskyi.

bpo-31825 [https://bugs.python.org/issue?@action=redirect&bpo=31825]: Fixed OverflowError in the ‘unicode-escape’ codec and in codecs.escape_decode() when decode an escaped non-ascii byte.

bpo-31618 [https://bugs.python.org/issue?@action=redirect&bpo=31618]: The per-frame tracing logic added in 3.7a1 has been altered so that frame->f_lineno is updated before either "line" or "opcode" events are emitted. Previously, opcode events were emitted first, and therefore would occasionally see stale line numbers on the frame. The behavior of this feature has changed slightly as a result: when both f_trace_lines and f_trace_opcodes are enabled, line events now occur first.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: Print the full context/cause chain of exceptions on interpreter exit, even if an exception in the chain is unhashable or compares equal to later ones. Patch by Zane Bitter.

bpo-31786 [https://bugs.python.org/issue?@action=redirect&bpo=31786]: Fix timeout rounding in the select module to round correctly negative timeouts between -1.0 and 0.0. The functions now block waiting for events as expected. Previously, the call was incorrectly non-blocking. Patch by Pablo Galindo.

bpo-31781 [https://bugs.python.org/issue?@action=redirect&bpo=31781]: Prevent crashes when calling methods of an uninitialized zipimport.zipimporter object. Patch by Oren Milman.

bpo-30399 [https://bugs.python.org/issue?@action=redirect&bpo=30399]: Standard repr() of BaseException with a single argument no longer contains redundant trailing comma.

bpo-31626 [https://bugs.python.org/issue?@action=redirect&bpo=31626]: Fixed a bug in debug memory allocator. There was a write to freed memory after shrinking a memory block.

bpo-30817 [https://bugs.python.org/issue?@action=redirect&bpo=30817]: PyErr_PrintEx() clears now the ignored exception that may be raised by _PySys_SetObjectId(), for example when no memory.

Library

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Two minor fixes for typing module: allow shallow copying instances of generic classes, improve interaction of __init_subclass__ with generics. Original PRs by Ivan Levkivskyi.

bpo-32214 [https://bugs.python.org/issue?@action=redirect&bpo=32214]: PEP 557, Data Classes. Provides a decorator which adds boilerplate methods to classes which use type annotations so specify fields.

bpo-27240 [https://bugs.python.org/issue?@action=redirect&bpo=27240]: The header folding algorithm for the new email policies has been rewritten, which also fixes bpo-30788 [https://bugs.python.org/issue?@action=redirect&bpo=30788], bpo-31831 [https://bugs.python.org/issue?@action=redirect&bpo=31831], and bpo-32182 [https://bugs.python.org/issue?@action=redirect&bpo=32182]. In particular, RFC2231 folding is now done correctly.

bpo-32186 [https://bugs.python.org/issue?@action=redirect&bpo=32186]: io.FileIO.readall() and io.FileIO.read() now release the GIL when getting the file size. Fixed hang of all threads with inaccessible NFS server. Patch by Nir Soffer.

bpo-32101 [https://bugs.python.org/issue?@action=redirect&bpo=32101]: Add sys.flags.dev_mode flag

bpo-32154 [https://bugs.python.org/issue?@action=redirect&bpo=32154]: The asyncio.windows_utils.socketpair() function has been removed: use directly socket.socketpair() which is available on all platforms since Python 3.5 (before, it wasn’t available on Windows). asyncio.windows_utils.socketpair() was just an alias to socket.socketpair on Python 3.5 and newer.

bpo-32089 [https://bugs.python.org/issue?@action=redirect&bpo=32089]: warnings: In development (-X dev) and debug mode (pydebug build), use the “default” action for ResourceWarning, rather than the “always” action, in the default warnings filters.

bpo-32107 [https://bugs.python.org/issue?@action=redirect&bpo=32107]: uuid.getnode() now preferentially returns universally administered MAC addresses if available, over locally administered MAC addresses. This makes a better guarantee for global uniqueness of UUIDs returned from uuid.uuid1(). If only locally administered MAC addresses are available, the first such one found is returned.

bpo-23033 [https://bugs.python.org/issue?@action=redirect&bpo=23033]: Wildcard is now supported in hostname when it is one and only character in the left most segment of hostname in second argument of ssl.match_hostname(). Patch by Mandeep Singh.

bpo-12239 [https://bugs.python.org/issue?@action=redirect&bpo=12239]: Make msilib.SummaryInformation.GetProperty() return None when the value of property is VT_EMPTY. Initial patch by Mark Mc Mahon.

bpo-28334 [https://bugs.python.org/issue?@action=redirect&bpo=28334]: Use os.path.expanduser() to find the ~/.netrc file in netrc.netrc. If it does not exist, FileNotFoundError is raised. Patch by Dimitri Merejkowsky.

bpo-32121 [https://bugs.python.org/issue?@action=redirect&bpo=32121]: Made tracemalloc.Traceback behave more like the traceback module, sorting the frames from oldest to most recent. Traceback.format() now accepts negative limit, truncating the result to the abs(limit) oldest frames. To get the old behaviour, one can use the new most_recent_first argument to Traceback.format(). (Patch by Jesse Bakker.)

bpo-31325 [https://bugs.python.org/issue?@action=redirect&bpo=31325]: Fix wrong usage of collections.namedtuple() in the RobotFileParser.parse() method. Initial patch by Robin Wellner.

bpo-12382 [https://bugs.python.org/issue?@action=redirect&bpo=12382]: msilib.OpenDatabase() now raises a better exception message when it couldn’t open or create an MSI file. Initial patch by William Tisäter.

bpo-19610 [https://bugs.python.org/issue?@action=redirect&bpo=19610]: setup() now warns about invalid types for some fields. The distutils.dist.Distribution class now warns when classifiers, keywords and platforms fields are not specified as a list or a string.

bpo-32071 [https://bugs.python.org/issue?@action=redirect&bpo=32071]: Added the -k command-line option to python -m unittest to run only tests that match the given pattern(s).

bpo-10049 [https://bugs.python.org/issue?@action=redirect&bpo=10049]: Added nullcontext no-op context manager to contextlib. This provides a simpler and faster alternative to ExitStack() when handling optional context managers.

bpo-28684 [https://bugs.python.org/issue?@action=redirect&bpo=28684]: The new test.support.skip_unless_bind_unix_socket() decorator is used here to skip asyncio tests that fail because the platform lacks a functional bind() function for unix domain sockets (as it is the case for non root users on the recent Android versions that run now SELinux in enforcing mode).

bpo-32110 [https://bugs.python.org/issue?@action=redirect&bpo=32110]: codecs.StreamReader.read(n) now returns not more than n characters/bytes for non-negative n. This makes it compatible with read() methods of other file-like objects.

bpo-27535 [https://bugs.python.org/issue?@action=redirect&bpo=27535]: The warnings module doesn’t leak memory anymore in the hidden warnings registry for the “ignore” action of warnings filters. warn_explicit() function doesn’t add the warning key to the registry anymore for the “ignore” action.

bpo-32088 [https://bugs.python.org/issue?@action=redirect&bpo=32088]: warnings: When Python is build is debug mode (Py_DEBUG), DeprecationWarning, PendingDeprecationWarning and ImportWarning warnings are now displayed by default.

bpo-1647489 [https://bugs.python.org/issue?@action=redirect&bpo=1647489]: Fixed searching regular expression patterns that could match an empty string. Non-empty string can now be correctly found after matching an empty string.

bpo-25054 [https://bugs.python.org/issue?@action=redirect&bpo=25054]: Added support of splitting on a pattern that could match an empty string.

bpo-32072 [https://bugs.python.org/issue?@action=redirect&bpo=32072]: Fixed issues with binary plists: Fixed saving bytearrays. Identical objects will be saved only once. Equal references will be load as identical objects. Added support for saving and loading recursive data structures.

bpo-32069 [https://bugs.python.org/issue?@action=redirect&bpo=32069]: Drop legacy SSL transport from asyncio, ssl.MemoryBIO is always used anyway.

bpo-32066 [https://bugs.python.org/issue?@action=redirect&bpo=32066]: asyncio: Support pathlib.Path in create_unix_connection; sock arg should be optional

bpo-32046 [https://bugs.python.org/issue?@action=redirect&bpo=32046]: Updates 2to3 to convert from operator.isCallable(obj) to callable(obj). Patch by Donghee Na.

bpo-32018 [https://bugs.python.org/issue?@action=redirect&bpo=32018]: inspect.signature should follow PEP 8 [https://peps.python.org/pep-0008/], if the parameter has an annotation and a default value. Patch by Donghee Na.

bpo-32025 [https://bugs.python.org/issue?@action=redirect&bpo=32025]: Add time.thread_time() and time.thread_time_ns()

bpo-32037 [https://bugs.python.org/issue?@action=redirect&bpo=32037]: Integers that fit in a signed 32-bit integer will be now pickled with protocol 0 using the INT opcode. This will decrease the size of a pickle, speed up pickling and unpickling, and make these integers be unpickled as int instances in Python 2.

bpo-32034 [https://bugs.python.org/issue?@action=redirect&bpo=32034]: Make asyncio.IncompleteReadError and LimitOverrunError pickleable.

bpo-32015 [https://bugs.python.org/issue?@action=redirect&bpo=32015]: Fixed the looping of asyncio in the case of reconnection the socket during waiting async read/write from/to the socket.

bpo-32011 [https://bugs.python.org/issue?@action=redirect&bpo=32011]: Restored support of loading marshal files with the TYPE_INT64 code. These files can be produced in Python 2.7.

bpo-28369 [https://bugs.python.org/issue?@action=redirect&bpo=28369]: Enhance add_reader/writer check that socket is not used by some transport. Before, only cases when add_reader/writer were called with an int FD were supported. Now the check is implemented correctly for all file-like objects.

bpo-31976 [https://bugs.python.org/issue?@action=redirect&bpo=31976]: Fix race condition when flushing a file is slow, which can cause a segfault if closing the file from another thread.

bpo-31985 [https://bugs.python.org/issue?@action=redirect&bpo=31985]: Formally deprecated aifc.openfp, sunau.openfp, and wave.openfp. Since change 7bc817d5ba917528e8bd07ec461c635291e7b06a in 1993, openfp in each of the three modules had been pointing to that module’s open function as a matter of backwards compatibility, though it had been both untested and undocumented.

bpo-21862 [https://bugs.python.org/issue?@action=redirect&bpo=21862]: cProfile command line now accepts -m module_name as an alternative to script path. Patch by Sanyam Khurana.

bpo-31970 [https://bugs.python.org/issue?@action=redirect&bpo=31970]: Reduce performance overhead of asyncio debug mode.

bpo-31843 [https://bugs.python.org/issue?@action=redirect&bpo=31843]: database argument of sqlite3.connect() now accepts a path-like object, instead of just a string.

bpo-31945 [https://bugs.python.org/issue?@action=redirect&bpo=31945]: Add Configurable blocksize to HTTPConnection and HTTPSConnection for improved upload throughput. Patch by Nir Soffer.

bpo-31943 [https://bugs.python.org/issue?@action=redirect&bpo=31943]: Add a cancelled() method to asyncio.Handle. Patch by Marat Sharafutdinov.

bpo-9678 [https://bugs.python.org/issue?@action=redirect&bpo=9678]: Fixed determining the MAC address in the uuid module: Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD, NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

bpo-30057 [https://bugs.python.org/issue?@action=redirect&bpo=30057]: Fix potential missed signal in signal.signal().

bpo-31933 [https://bugs.python.org/issue?@action=redirect&bpo=31933]: Fix Blake2 params leaf_size and node_offset on big endian platforms. Patch by Jack O’Connor.

bpo-21423 [https://bugs.python.org/issue?@action=redirect&bpo=21423]: Add an initializer argument to {Process,Thread}PoolExecutor

bpo-31927 [https://bugs.python.org/issue?@action=redirect&bpo=31927]: Fixed compilation of the socket module on NetBSD 8. Fixed assertion failure or reading arbitrary data when parse a AF_BLUETOOTH address on NetBSD and DragonFly BSD.

bpo-27666 [https://bugs.python.org/issue?@action=redirect&bpo=27666]: Fixed stack corruption in curses.box() and curses.ungetmouse() when the size of types chtype or mmask_t is less than the size of C long. curses.box() now accepts characters as arguments. Based on patch by Steve Fink.

bpo-31917 [https://bugs.python.org/issue?@action=redirect&bpo=31917]: Add 3 new clock identifiers: time.CLOCK_BOOTTIME, time.CLOCK_PROF and time.CLOCK_UPTIME.

bpo-31897 [https://bugs.python.org/issue?@action=redirect&bpo=31897]: plistlib now catches more errors when read binary plists and raises InvalidFileException instead of unexpected exceptions.

bpo-25720 [https://bugs.python.org/issue?@action=redirect&bpo=25720]: Fix the method for checking pad state of curses WINDOW. Patch by Masayuki Yamamoto.

bpo-31893 [https://bugs.python.org/issue?@action=redirect&bpo=31893]: Fixed the layout of the kqueue_event structure on OpenBSD and NetBSD. Fixed the comparison of the kqueue_event objects.

bpo-31891 [https://bugs.python.org/issue?@action=redirect&bpo=31891]: Fixed building the curses module on NetBSD.

bpo-31884 [https://bugs.python.org/issue?@action=redirect&bpo=31884]: added required constants to subprocess module for setting priority on windows

bpo-28281 [https://bugs.python.org/issue?@action=redirect&bpo=28281]: Remove year (1-9999) limits on the Calendar.weekday() function. Patch by Mark Gollahon.

bpo-31702 [https://bugs.python.org/issue?@action=redirect&bpo=31702]: crypt.mksalt() now allows to specify the number of rounds for SHA-256 and SHA-512 hashing.

bpo-30639 [https://bugs.python.org/issue?@action=redirect&bpo=30639]: inspect.getfile() no longer computes the repr of unknown objects to display in an error message, to protect against badly behaved custom reprs.

bpo-30768 [https://bugs.python.org/issue?@action=redirect&bpo=30768]: Fix the pthread+semaphore implementation of PyThread_acquire_lock_timed() when called with timeout > 0 and intr_flag=0: recompute the timeout if sem_timedwait() is interrupted by a signal (EINTR). See also the PEP 475 [https://peps.python.org/pep-0475/].

bpo-31854 [https://bugs.python.org/issue?@action=redirect&bpo=31854]: Add mmap.ACCESS_DEFAULT constant.

bpo-31834 [https://bugs.python.org/issue?@action=redirect&bpo=31834]: Use optimized code for BLAKE2 only with SSSE3+. The pure SSE2 implementation is slower than the pure C reference implementation.

bpo-28292 [https://bugs.python.org/issue?@action=redirect&bpo=28292]: Calendar.itermonthdates() will now consistently raise an exception when a date falls outside of the 0001-01-01 through 9999-12-31 range. To support applications that cannot tolerate such exceptions, the new methods itermonthdays3() and itermonthdays4() are added. The new methods return tuples and are not restricted by the range supported by datetime.date.

bpo-28564 [https://bugs.python.org/issue?@action=redirect&bpo=28564]: The shutil.rmtree() function has been sped up to 20–40%. This was done using the os.scandir() function.

bpo-28416 [https://bugs.python.org/issue?@action=redirect&bpo=28416]: Instances of pickle.Pickler subclass with the persistent_id() method and pickle.Unpickler subclass with the persistent_load() method no longer create reference cycles.

bpo-31653 [https://bugs.python.org/issue?@action=redirect&bpo=31653]: Don’t release the GIL if we can acquire a multiprocessing semaphore immediately.

bpo-28326 [https://bugs.python.org/issue?@action=redirect&bpo=28326]: Fix multiprocessing.Process when stdout and/or stderr is closed or None.

bpo-20825 [https://bugs.python.org/issue?@action=redirect&bpo=20825]: Add subnet_of and superset_of containment tests to ipaddress.IPv6Network and ipaddress.IPv4Network. Patch by Michel Albert and Cheryl Sabella.

bpo-31827 [https://bugs.python.org/issue?@action=redirect&bpo=31827]: Remove the os.stat_float_times() function. It was introduced in Python 2.3 for backward compatibility with Python 2.2, and was deprecated since Python 3.1.

bpo-31756 [https://bugs.python.org/issue?@action=redirect&bpo=31756]: Add a subprocess.Popen(text=False) keyword argument to subprocess functions to be more explicit about when the library should attempt to decode outputs into text. Patch by Andrew Clegg.

bpo-31819 [https://bugs.python.org/issue?@action=redirect&bpo=31819]: Add AbstractEventLoop.sock_recv_into().

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: If nested log adapters are used, the inner process() methods are no longer omitted.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: The manager property on LoggerAdapter objects is now properly settable.

bpo-31806 [https://bugs.python.org/issue?@action=redirect&bpo=31806]: Fix timeout rounding in time.sleep(), threading.Lock.acquire() and socket.socket.settimeout() to round correctly negative timeouts between -1.0 and 0.0. The functions now block waiting for events as expected. Previously, the call was incorrectly non-blocking. Patch by Pablo Galindo.

bpo-31803 [https://bugs.python.org/issue?@action=redirect&bpo=31803]: time.clock() and time.get_clock_info(‘clock’) now emit a DeprecationWarning warning.

bpo-31800 [https://bugs.python.org/issue?@action=redirect&bpo=31800]: Extended support for parsing UTC offsets. strptime ‘%z’ can now parse the output generated by datetime.isoformat, including seconds and microseconds.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: traceback: Fix a TypeError that occurred during printing of exception tracebacks when either the current exception or an exception in its context/cause chain is unhashable. Patch by Zane Bitter.

bpo-30541 [https://bugs.python.org/issue?@action=redirect&bpo=30541]: Add new function to seal a mock and prevent the automatically creation of child mocks. Patch by Mario Corchero.

bpo-31784 [https://bugs.python.org/issue?@action=redirect&bpo=31784]: Implement the PEP 564 [https://peps.python.org/pep-0564/], add new 6 new functions with nanosecond resolution to the time module: clock_gettime_ns(), clock_settime_ns(), monotonic_ns(), perf_counter_ns(), process_time_ns(), time_ns().

bpo-30143 [https://bugs.python.org/issue?@action=redirect&bpo=30143]: 2to3 now generates a code that uses abstract collection classes from collections.abc rather than collections.

bpo-31770 [https://bugs.python.org/issue?@action=redirect&bpo=31770]: Prevent a crash when calling the __init__() method of a sqlite3.Cursor object more than once. Patch by Oren Milman.

bpo-31764 [https://bugs.python.org/issue?@action=redirect&bpo=31764]: Prevent a crash in sqlite3.Cursor.close() in case the Cursor object is uninitialized. Patch by Oren Milman.

bpo-31752 [https://bugs.python.org/issue?@action=redirect&bpo=31752]: Fix possible crash in timedelta constructor called with custom integers.

bpo-31620 [https://bugs.python.org/issue?@action=redirect&bpo=31620]: an empty asyncio.Queue now doesn’t leak memory when queue.get pollers timeout

bpo-31690 [https://bugs.python.org/issue?@action=redirect&bpo=31690]: Allow the flags re.ASCII, re.LOCALE, and re.UNICODE to be used as group flags for regular expressions.

bpo-30349 [https://bugs.python.org/issue?@action=redirect&bpo=30349]: FutureWarning is now emitted if a regular expression contains character set constructs that will change semantically in the future (nested sets and set operations).

bpo-31664 [https://bugs.python.org/issue?@action=redirect&bpo=31664]: Added support for the Blowfish hashing in the crypt module.

bpo-31632 [https://bugs.python.org/issue?@action=redirect&bpo=31632]: Fix method set_protocol() of class _SSLProtocolTransport in asyncio module. This method was previously modifying a wrong reference to the protocol.

bpo-15037 [https://bugs.python.org/issue?@action=redirect&bpo=15037]: Added a workaround for getkey() in curses for ncurses 5.7 and earlier.

bpo-31307 [https://bugs.python.org/issue?@action=redirect&bpo=31307]: Allow use of bytes objects for arguments to configparser.ConfigParser.read(). Patch by Vincent Michel.

bpo-31334 [https://bugs.python.org/issue?@action=redirect&bpo=31334]: Fix poll.poll([timeout]) in the select module for arbitrary negative timeouts on all OSes where it can only be a non-negative integer or -1. Patch by Riccardo Coccioli.

bpo-31310 [https://bugs.python.org/issue?@action=redirect&bpo=31310]: multiprocessing’s semaphore tracker should be launched again if crashed.

bpo-31308 [https://bugs.python.org/issue?@action=redirect&bpo=31308]: Make multiprocessing’s forkserver process immune to Ctrl-C and other user interruptions. If it crashes, restart it when necessary.

bpo-31245 [https://bugs.python.org/issue?@action=redirect&bpo=31245]: Added support for AF_UNIX socket in asyncio create_datagram_endpoint.

bpo-30553 [https://bugs.python.org/issue?@action=redirect&bpo=30553]: Add HTTP/2 status code 421 (Misdirected Request) to http.HTTPStatus. Patch by Vitor Pereira.

Documentation

bpo-32105 [https://bugs.python.org/issue?@action=redirect&bpo=32105]: Added asyncio.BaseEventLoop.connect_accepted_socket versionadded marker.

Tests

bpo-31380 [https://bugs.python.org/issue?@action=redirect&bpo=31380]: Skip test_httpservers test_undecodable_file on macOS: fails on APFS.

bpo-31705 [https://bugs.python.org/issue?@action=redirect&bpo=31705]: Skip test_socket.test_sha256() on Linux kernel older than 4.5. The test fails with ENOKEY on kernel 3.10 (on ppc64le). A fix was merged into the kernel 4.5.

bpo-32138 [https://bugs.python.org/issue?@action=redirect&bpo=32138]: Skip on Android test_faulthandler tests that raise SIGSEGV and remove the test.support.requires_android_level decorator.

bpo-32136 [https://bugs.python.org/issue?@action=redirect&bpo=32136]: The runtime embedding tests have been split out from Lib/test/test_capi.py into a new Lib/test/test_embed.py file.

bpo-28668 [https://bugs.python.org/issue?@action=redirect&bpo=28668]: test.support.requires_multiprocessing_queue is removed. Skip tests with test.support.import_module(‘multiprocessing.synchronize’) instead when the semaphore implementation is broken or missing.

bpo-32126 [https://bugs.python.org/issue?@action=redirect&bpo=32126]: Skip test_get_event_loop_new_process in test.test_asyncio.test_events when sem_open() is not functional.

bpo-31174 [https://bugs.python.org/issue?@action=redirect&bpo=31174]: Fix test_tools.test_unparse: DirectoryTestCase now stores the names sample to always test the same files. It prevents false alarms when hunting reference leaks.

Build

bpo-28538 [https://bugs.python.org/issue?@action=redirect&bpo=28538]: Revert the previous changes, the if_nameindex structure is defined by Unified Headers.

bpo-28762 [https://bugs.python.org/issue?@action=redirect&bpo=28762]: Revert the last commit, the F_LOCK macro is defined by Android Unified Headers.

bpo-29040 [https://bugs.python.org/issue?@action=redirect&bpo=29040]: Support building Android with Unified Headers. The first NDK release to support Unified Headers is android-ndk-r14.

bpo-32059 [https://bugs.python.org/issue?@action=redirect&bpo=32059]: detect_modules() in setup.py now also searches the sysroot paths when cross-compiling.

bpo-31957 [https://bugs.python.org/issue?@action=redirect&bpo=31957]: Fixes Windows SDK version detection when building for Windows.

bpo-31609 [https://bugs.python.org/issue?@action=redirect&bpo=31609]: Fixes quotes in PCbuild/clean.bat

bpo-31934 [https://bugs.python.org/issue?@action=redirect&bpo=31934]: Abort the build when building out of a not clean source tree.

bpo-31926 [https://bugs.python.org/issue?@action=redirect&bpo=31926]: Fixed Argument Clinic sometimes causing compilation errors when there was more than one function and/or method in a .c file with the same name.

bpo-28791 [https://bugs.python.org/issue?@action=redirect&bpo=28791]: Update Windows builds to use SQLite 3.21.0.

bpo-28791 [https://bugs.python.org/issue?@action=redirect&bpo=28791]: Update OS X installer to use SQLite 3.21.0.

bpo-28643 [https://bugs.python.org/issue?@action=redirect&bpo=28643]: Record profile-opt build progress with stamp files.

bpo-31866 [https://bugs.python.org/issue?@action=redirect&bpo=31866]: Finish removing support for AtheOS.

Windows

bpo-1102 [https://bugs.python.org/issue?@action=redirect&bpo=1102]: Return None when View.Fetch() returns ERROR_NO_MORE_ITEMS instead of raising MSIError. Initial patch by Anthony Tuininga.

bpo-31944 [https://bugs.python.org/issue?@action=redirect&bpo=31944]: Fixes Modify button in Apps and Features dialog.

bpo-20486 [https://bugs.python.org/issue?@action=redirect&bpo=20486]: Implement the Database.Close() method to help closing MSI database objects.

bpo-31857 [https://bugs.python.org/issue?@action=redirect&bpo=31857]: Make the behavior of USE_STACKCHECK deterministic in a multi-threaded environment.

macOS

bpo-31392 [https://bugs.python.org/issue?@action=redirect&bpo=31392]: Update macOS installer to use OpenSSL 1.0.2m

IDLE

bpo-32207 [https://bugs.python.org/issue?@action=redirect&bpo=32207]: Improve tk event exception tracebacks in IDLE. When tk event handling is driven by IDLE’s run loop, a confusing and distracting queue.EMPTY traceback context is no longer added to tk event exception tracebacks. The traceback is now the same as when event handling is driven by user code. Patch based on a suggestion by Serhiy Storchaka.

bpo-32164 [https://bugs.python.org/issue?@action=redirect&bpo=32164]: Delete unused file idlelib/tabbedpages.py. Use of TabbedPageSet in configdialog was replaced by ttk.Notebook.

bpo-32100 [https://bugs.python.org/issue?@action=redirect&bpo=32100]: IDLE: Fix old and new bugs in pathbrowser; improve tests. Patch mostly by Cheryl Sabella.

bpo-31858 [https://bugs.python.org/issue?@action=redirect&bpo=31858]: IDLE – Restrict shell prompt manipulation to the shell. Editor and output windows only see an empty last prompt line. This simplifies the code and fixes a minor bug when newline is inserted. Sys.ps1, if present, is read on Shell start-up, but is not set or changed.

bpo-31860 [https://bugs.python.org/issue?@action=redirect&bpo=31860]: The font sample in the IDLE configuration dialog is now editable. Changes persist while IDLE remains open

bpo-31836 [https://bugs.python.org/issue?@action=redirect&bpo=31836]: Test_code_module now passes if run after test_idle, which sets ps1. The code module uses sys.ps1 if present or sets it to ‘>>> ‘ if not. Test_code_module now properly tests both behaviors. Ditto for ps2.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: Fix a TypeError that caused a shell restart when printing a traceback that includes an exception that is unhashable. Patch by Zane Bitter.

bpo-13802 [https://bugs.python.org/issue?@action=redirect&bpo=13802]: Use non-Latin characters in the IDLE’s Font settings sample. Even if one selects a font that defines a limited subset of the unicode Basic Multilingual Plane, tcl/tk will use other fonts that define a character. The expanded example give users of non-Latin characters a better idea of what they might see in IDLE’s shell and editors. To make room for the expanded sample, frames on the Font tab are re-arranged. The Font/Tabs help explains a bit about the additions.

Tools/Demos

bpo-32159 [https://bugs.python.org/issue?@action=redirect&bpo=32159]: Remove CVS and Subversion tools: remove svneol.py and treesync.py scripts. CPython migrated from CVS to Subversion, to Mercurial, and then to Git. CVS and Subversion are no longer used to develop CPython.

bpo-30722 [https://bugs.python.org/issue?@action=redirect&bpo=30722]: Make redemo work with Python 3.6 and newer versions. Also, remove the LOCALE option since it doesn’t work with string patterns in Python 3. Patch by Christoph Sarnowski.

C API

bpo-20891 [https://bugs.python.org/issue?@action=redirect&bpo=20891]: Fix PyGILState_Ensure(). When PyGILState_Ensure() is called in a non-Python thread before PyEval_InitThreads(), only call PyEval_InitThreads() after calling PyThreadState_New() to fix a crash.

bpo-32125 [https://bugs.python.org/issue?@action=redirect&bpo=32125]: The Py_UseClassExceptionsFlag flag has been removed. It was deprecated and wasn’t used anymore since Python 2.0.

bpo-25612 [https://bugs.python.org/issue?@action=redirect&bpo=25612]: Move the current exception state from the frame object to the co-routine. This simplifies the interpreter and fixes a couple of obscure bugs caused by having swap exception state when entering or exiting a generator.

bpo-23699 [https://bugs.python.org/issue?@action=redirect&bpo=23699]: Add Py_RETURN_RICHCOMPARE macro to reduce boilerplate code in rich comparison functions.

bpo-30697 [https://bugs.python.org/issue?@action=redirect&bpo=30697]: The PyExc_RecursionErrorInst singleton is removed and PyErr_NormalizeException() does not use it anymore. This singleton is persistent and its members being never cleared may cause a segfault during finalization of the interpreter. See also bpo-22898 [https://bugs.python.org/issue?@action=redirect&bpo=22898].

Python 3.7.0 alpha 2

Release date: 2017-10-16

Core and Builtins

bpo-31558 [https://bugs.python.org/issue?@action=redirect&bpo=31558]: gc.freeze() is a new API that allows for moving all objects currently tracked by the garbage collector to a permanent generation, effectively removing them from future collection events. This can be used to protect those objects from having their PyGC_Head mutated. In effect, this enables great copy-on-write stability at fork().

bpo-31642 [https://bugs.python.org/issue?@action=redirect&bpo=31642]: Restored blocking “from package import module” by setting sys.modules[“package.module”] to None.

bpo-31708 [https://bugs.python.org/issue?@action=redirect&bpo=31708]: Allow use of asynchronous generator expressions in synchronous functions.

bpo-31709 [https://bugs.python.org/issue?@action=redirect&bpo=31709]: Drop support of asynchronous __aiter__.

bpo-30404 [https://bugs.python.org/issue?@action=redirect&bpo=30404]: The -u option now makes the stdout and stderr streams unbuffered rather than line-buffered.

bpo-31619 [https://bugs.python.org/issue?@action=redirect&bpo=31619]: Fixed a ValueError when convert a string with large number of underscores to integer with binary base.

bpo-31602 [https://bugs.python.org/issue?@action=redirect&bpo=31602]: Fix an assertion failure in zipimporter.get_source() in case of a bad zlib.decompress(). Patch by Oren Milman.

bpo-31592 [https://bugs.python.org/issue?@action=redirect&bpo=31592]: Fixed an assertion failure in Python parser in case of a bad unicodedata.normalize(). Patch by Oren Milman.

bpo-31588 [https://bugs.python.org/issue?@action=redirect&bpo=31588]: Raise a TypeError with a helpful error message when class creation fails due to a metaclass with a bad __prepare__() method. Patch by Oren Milman.

bpo-31574 [https://bugs.python.org/issue?@action=redirect&bpo=31574]: Importlib was instrumented with two dtrace probes to profile import timing.

bpo-31566 [https://bugs.python.org/issue?@action=redirect&bpo=31566]: Fix an assertion failure in _warnings.warn() in case of a bad __name__ global. Patch by Oren Milman.

bpo-31506 [https://bugs.python.org/issue?@action=redirect&bpo=31506]: Improved the error message logic for object.__new__ and object.__init__.

bpo-31505 [https://bugs.python.org/issue?@action=redirect&bpo=31505]: Fix an assertion failure in json, in case _json.make_encoder() received a bad encoder() argument. Patch by Oren Milman.

bpo-31492 [https://bugs.python.org/issue?@action=redirect&bpo=31492]: Fix assertion failures in case of failing to import from a module with a bad __name__ attribute, and in case of failing to access an attribute of such a module. Patch by Oren Milman.

bpo-31478 [https://bugs.python.org/issue?@action=redirect&bpo=31478]: Fix an assertion failure in _random.Random.seed() in case the argument has a bad __abs__() method. Patch by Oren Milman.

bpo-31336 [https://bugs.python.org/issue?@action=redirect&bpo=31336]: Speed up class creation by 10-20% by reducing the overhead in the necessary special method lookups. Patch by Stefan Behnel.

bpo-31415 [https://bugs.python.org/issue?@action=redirect&bpo=31415]: Add -X importtime option to show how long each import takes. It can be used to optimize application’s startup time. Support the PYTHONPROFILEIMPORTTIME as an equivalent way to enable this.

bpo-31410 [https://bugs.python.org/issue?@action=redirect&bpo=31410]: Optimized calling wrapper and classmethod descriptors.

bpo-31353 [https://bugs.python.org/issue?@action=redirect&bpo=31353]: PEP 553 [https://peps.python.org/pep-0553/] - Add a new built-in called breakpoint() which calls sys.breakpointhook(). By default this imports pdb and calls pdb.set_trace(), but users may override sys.breakpointhook() to call whatever debugger they want. The original value of the hook is saved in sys.__breakpointhook__.

bpo-17852 [https://bugs.python.org/issue?@action=redirect&bpo=17852]: Maintain a list of open buffered files, flush them before exiting the interpreter. Based on a patch from Armin Rigo.

bpo-31315 [https://bugs.python.org/issue?@action=redirect&bpo=31315]: Fix an assertion failure in imp.create_dynamic(), when spec.name is not a string. Patch by Oren Milman.

bpo-31311 [https://bugs.python.org/issue?@action=redirect&bpo=31311]: Fix a crash in the __setstate__() method of ctypes._CData, in case of a bad __dict__. Patch by Oren Milman.

bpo-31293 [https://bugs.python.org/issue?@action=redirect&bpo=31293]: Fix crashes in true division and multiplication of a timedelta object by a float with a bad as_integer_ratio() method. Patch by Oren Milman.

bpo-31285 [https://bugs.python.org/issue?@action=redirect&bpo=31285]: Fix an assertion failure in warnings.warn_explicit, when the return value of the received loader’s get_source() has a bad splitlines() method. Patch by Oren Milman.

bpo-30406 [https://bugs.python.org/issue?@action=redirect&bpo=30406]: Make async and await proper keywords, as specified in PEP 492 [https://peps.python.org/pep-0492/].

Library

bpo-30058 [https://bugs.python.org/issue?@action=redirect&bpo=30058]: Fixed buffer overflow in select.kqueue.control().

bpo-31672 [https://bugs.python.org/issue?@action=redirect&bpo=31672]: idpattern in string.Template matched some non-ASCII characters. Now it uses -i regular expression local flag to avoid non-ASCII characters.

bpo-31701 [https://bugs.python.org/issue?@action=redirect&bpo=31701]: On Windows, faulthandler.enable() now ignores MSC and COM exceptions.

bpo-31728 [https://bugs.python.org/issue?@action=redirect&bpo=31728]: Prevent crashes in _elementtree due to unsafe cleanup of Element.text and Element.tail. Patch by Oren Milman.

bpo-31671 [https://bugs.python.org/issue?@action=redirect&bpo=31671]: Now re.compile() converts passed RegexFlag to normal int object before compiling. bm_regex_compile benchmark shows 14% performance improvements.

bpo-30397 [https://bugs.python.org/issue?@action=redirect&bpo=30397]: The types of compiled regular objects and match objects are now exposed as re.Pattern and re.Match. This adds information in pydoc output for the re module.

bpo-31675 [https://bugs.python.org/issue?@action=redirect&bpo=31675]: Fixed memory leaks in Tkinter’s methods splitlist() and split() when pass a string larger than 2 GiB.

bpo-31673 [https://bugs.python.org/issue?@action=redirect&bpo=31673]: Fixed typo in the name of Tkinter’s method adderrorinfo().

bpo-31648 [https://bugs.python.org/issue?@action=redirect&bpo=31648]: Improvements to path predicates in ElementTree: Allow whitespace around predicate parts, i.e. “[a = ‘text’]” instead of requiring the less readable “[a=’text’]”. Add support for text comparison of the current node, like “[.=’text’]”. Patch by Stefan Behnel.

bpo-30806 [https://bugs.python.org/issue?@action=redirect&bpo=30806]: Fix the string representation of a netrc object.

bpo-31638 [https://bugs.python.org/issue?@action=redirect&bpo=31638]: Add optional argument compressed to zipapp.create_archive, and add option --compress to the command line interface of zipapp.

bpo-25351 [https://bugs.python.org/issue?@action=redirect&bpo=25351]: Avoid venv activate failures with undefined variables

bpo-20519 [https://bugs.python.org/issue?@action=redirect&bpo=20519]: Avoid ctypes use (if possible) and improve import time for uuid.

bpo-28293 [https://bugs.python.org/issue?@action=redirect&bpo=28293]: The regular expression cache is no longer completely dumped when it is full.

bpo-31596 [https://bugs.python.org/issue?@action=redirect&bpo=31596]: Added pthread_getcpuclockid() to the time module

bpo-27494 [https://bugs.python.org/issue?@action=redirect&bpo=27494]: Make 2to3 accept a trailing comma in generator expressions. For example, set(x for x in [],) is now allowed.

bpo-30347 [https://bugs.python.org/issue?@action=redirect&bpo=30347]: Stop crashes when concurrently iterate over itertools.groupby() iterators.

bpo-30346 [https://bugs.python.org/issue?@action=redirect&bpo=30346]: An iterator produced by itertools.groupby() iterator now becomes exhausted after advancing the groupby iterator.

bpo-31556 [https://bugs.python.org/issue?@action=redirect&bpo=31556]: Cancel asyncio.wait_for future faster if timeout <= 0

bpo-31540 [https://bugs.python.org/issue?@action=redirect&bpo=31540]: Allow passing a context object in concurrent.futures.ProcessPoolExecutor constructor. Also, free job resources in concurrent.futures.ProcessPoolExecutor earlier to improve memory usage when a worker waits for new jobs.

bpo-31516 [https://bugs.python.org/issue?@action=redirect&bpo=31516]: threading.current_thread() should not return a dummy thread at shutdown.

bpo-31525 [https://bugs.python.org/issue?@action=redirect&bpo=31525]: In the sqlite module, require the sqlite3_prepare_v2 API. Thus, the sqlite module now requires sqlite version at least 3.3.9.

bpo-26510 [https://bugs.python.org/issue?@action=redirect&bpo=26510]: argparse subparsers are now required by default. This matches behaviour in Python 2. For optional subparsers, use the new parameter add_subparsers(required=False). Patch by Anthony Sottile. (As of 3.7.0rc1, the default was changed to not required as had been the case since Python 3.3.)

bpo-27541 [https://bugs.python.org/issue?@action=redirect&bpo=27541]: Reprs of subclasses of some collection and iterator classes (bytearray, array.array, collections.deque, collections.defaultdict, itertools.count, itertools.repeat) now contain actual type name instead of hardcoded names of the base class.

bpo-31351 [https://bugs.python.org/issue?@action=redirect&bpo=31351]: python -m ensurepip now exits with non-zero exit code if pip bootstrapping has failed.

bpo-31389 [https://bugs.python.org/issue?@action=redirect&bpo=31389]: pdb.set_trace() now takes an optional keyword-only argument header. If given, this is printed to the console just before debugging begins.

Documentation

bpo-31537 [https://bugs.python.org/issue?@action=redirect&bpo=31537]: Fix incorrect usage of get_history_length in readline documentation example code. Patch by Brad Smith.

bpo-30085 [https://bugs.python.org/issue?@action=redirect&bpo=30085]: The operator functions without double underscores are preferred for clarity. The one with underscores are only kept for back-compatibility.

Build

bpo-31696 [https://bugs.python.org/issue?@action=redirect&bpo=31696]: Improve compiler version information in sys.version when Python is built with Clang.

bpo-31625 [https://bugs.python.org/issue?@action=redirect&bpo=31625]: Stop using ranlib on static libraries. Instead, we assume ar supports the ‘s’ flag.

bpo-31624 [https://bugs.python.org/issue?@action=redirect&bpo=31624]: Remove support for BSD/OS.

bpo-22140 [https://bugs.python.org/issue?@action=redirect&bpo=22140]: Prevent double substitution of prefix in python-config.sh.

bpo-31569 [https://bugs.python.org/issue?@action=redirect&bpo=31569]: Correct PCBuild/ case to PCbuild/ in build scripts and documentation.

bpo-31536 [https://bugs.python.org/issue?@action=redirect&bpo=31536]: Avoid wholesale rebuild after make regen-all if nothing changed.

IDLE

bpo-31460 [https://bugs.python.org/issue?@action=redirect&bpo=31460]: Simplify the API of IDLE’s Module Browser. Passing a widget instead of an flist with a root widget opens the option of creating a browser frame that is only part of a window. Passing a full file name instead of pieces assumed to come from a .py file opens the possibility of browsing python files that do not end in .py.

bpo-31649 [https://bugs.python.org/issue?@action=redirect&bpo=31649]: IDLE - Make _htest, _utest parameters keyword only.

bpo-31559 [https://bugs.python.org/issue?@action=redirect&bpo=31559]: Remove test order dependence in idle_test.test_browser.

bpo-31459 [https://bugs.python.org/issue?@action=redirect&bpo=31459]: Rename IDLE’s module browser from Class Browser to Module Browser. The original module-level class and method browser became a module browser, with the addition of module-level functions, years ago. Nested classes and functions were added yesterday. For back-compatibility, the virtual event <<open-class-browser>>, which appears on the Keys tab of the Settings dialog, is not changed. Patch by Cheryl Sabella.

bpo-31500 [https://bugs.python.org/issue?@action=redirect&bpo=31500]: Default fonts now are scaled on HiDPI displays.

bpo-1612262 [https://bugs.python.org/issue?@action=redirect&bpo=1612262]: IDLE module browser now shows nested classes and functions. Original patches for code and tests by Guilherme Polo and Cheryl Sabella, respectively.

C API

bpo-28280 [https://bugs.python.org/issue?@action=redirect&bpo=28280]: Make PyMapping_Keys(), PyMapping_Values() and PyMapping_Items() always return a list (rather than a list or a tuple). Patch by Oren Milman.

bpo-31532 [https://bugs.python.org/issue?@action=redirect&bpo=31532]: Fix memory corruption due to allocator mix in getpath.c between Py_GetPath() and Py_SetPath()

bpo-25658 [https://bugs.python.org/issue?@action=redirect&bpo=25658]: Implement PEP 539 [https://peps.python.org/pep-0539/] for Thread Specific Storage (TSS) API: it is a new Thread Local Storage (TLS) API to CPython which would supersede use of the existing TLS API within the CPython interpreter, while deprecating the existing API. PEP written by Erik M. Bray, patch by Masayuki Yamamoto.

Python 3.7.0 alpha 1

Release date: 2017-09-19

Security

bpo-29781 [https://bugs.python.org/issue?@action=redirect&bpo=29781]: SSLObject.version() now correctly returns None when handshake over BIO has not been performed yet.

bpo-29505 [https://bugs.python.org/issue?@action=redirect&bpo=29505]: Add fuzz tests for float(str), int(str), unicode(str); for oss-fuzz.

bpo-30947 [https://bugs.python.org/issue?@action=redirect&bpo=30947]: Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to get security fixes.

bpo-30730 [https://bugs.python.org/issue?@action=redirect&bpo=30730]: Prevent environment variables injection in subprocess on Windows. Prevent passing other environment variables and command arguments.

bpo-30694 [https://bugs.python.org/issue?@action=redirect&bpo=30694]: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of multiple security vulnerabilities including: CVE 2017-9233 [https://www.cve.org/CVERecord?id=CVE-2017-9233] (External entity infinite loop DoS), CVE 2016-9063 [https://www.cve.org/CVERecord?id=CVE-2016-9063] (Integer overflow, re-fix), CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] (Fix regression bugs from 2.2.0’s fix to CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718]) and CVE 2012-0876 [https://www.cve.org/CVERecord?id=CVE-2012-0876] (Counter hash flooding with SipHash). Note: the CVE 2016-5300 [https://www.cve.org/CVERecord?id=CVE-2016-5300] (Use os-specific entropy sources like getrandom) doesn’t impact Python, since Python already gets entropy from the OS to set the expat secret using XML_SetHashSalt().

bpo-30500 [https://bugs.python.org/issue?@action=redirect&bpo=30500]: Fix urllib.parse.splithost() to correctly parse fragments. For example, splithost('//127.0.0.1#@evil.com/') now correctly returns the 127.0.0.1 host, instead of treating @evil.com as the host in an authentication (login@host).

bpo-29591 [https://bugs.python.org/issue?@action=redirect&bpo=29591]: Update expat copy from 2.1.1 to 2.2.0 to get fixes of CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] and CVE 2016-4472 [https://www.cve.org/CVERecord?id=CVE-2016-4472]. See https://sourceforge.net/p/expat/bugs/537/ for more information.

Core and Builtins

bpo-31490 [https://bugs.python.org/issue?@action=redirect&bpo=31490]: Fix an assertion failure in ctypes class definition, in case the class has an attribute whose name is specified in _anonymous_ but not in _fields_. Patch by Oren Milman.

bpo-31471 [https://bugs.python.org/issue?@action=redirect&bpo=31471]: Fix an assertion failure in subprocess.Popen() on Windows, in case the env argument has a bad keys() method. Patch by Oren Milman.

bpo-31418 [https://bugs.python.org/issue?@action=redirect&bpo=31418]: Fix an assertion failure in PyErr_WriteUnraisable() in case of an exception with a bad __module__ attribute. Patch by Oren Milman.

bpo-31416 [https://bugs.python.org/issue?@action=redirect&bpo=31416]: Fix assertion failures in case of a bad warnings.filters or warnings.defaultaction. Patch by Oren Milman.

bpo-28411 [https://bugs.python.org/issue?@action=redirect&bpo=28411]: Change direct usage of PyInterpreterState.modules to PyImport_GetModuleDict(). Also introduce more uniformity in other code that deals with sys.modules. This helps reduce complications when working on sys.modules.

bpo-28411 [https://bugs.python.org/issue?@action=redirect&bpo=28411]: Switch to the abstract API when dealing with PyInterpreterState.modules. This allows later support for all dict subclasses and other Mapping implementations. Also add a PyImport_GetModule() function to reduce a bunch of duplicated code.

bpo-31411 [https://bugs.python.org/issue?@action=redirect&bpo=31411]: Raise a TypeError instead of SystemError in case warnings.onceregistry is not a dictionary. Patch by Oren Milman.

bpo-31344 [https://bugs.python.org/issue?@action=redirect&bpo=31344]: For finer control of tracing behaviour when testing the interpreter, two new frame attributes have been added to control the emission of particular trace events: f_trace_lines (True by default) to turn off per-line trace events; and f_trace_opcodes (False by default) to turn on per-opcode trace events.

bpo-31373 [https://bugs.python.org/issue?@action=redirect&bpo=31373]: Fix several possible instances of undefined behavior due to floating-point demotions.

bpo-30465 [https://bugs.python.org/issue?@action=redirect&bpo=30465]: Location information (lineno and col_offset) in f-strings is now (mostly) correct. This fixes tools like flake8 from showing warnings on the wrong line (typically the first line of the file).

bpo-30860 [https://bugs.python.org/issue?@action=redirect&bpo=30860]: Consolidate CPython’s global runtime state under a single struct. This improves discoverability of the runtime state.

bpo-31347 [https://bugs.python.org/issue?@action=redirect&bpo=31347]: Fix possible undefined behavior in _PyObject_FastCall_Prepend.

bpo-31343 [https://bugs.python.org/issue?@action=redirect&bpo=31343]: Include sys/sysmacros.h for major(), minor(), and makedev(). GNU C library plans to remove the functions from sys/types.h.

bpo-31291 [https://bugs.python.org/issue?@action=redirect&bpo=31291]: Fix an assertion failure in zipimport.zipimporter.get_data on Windows, when the return value of pathname.replace('/','\\') isn’t a string. Patch by Oren Milman.

bpo-31271 [https://bugs.python.org/issue?@action=redirect&bpo=31271]: Fix an assertion failure in the write() method of io.TextIOWrapper, when the encoder doesn’t return a bytes object. Patch by Oren Milman.

bpo-31243 [https://bugs.python.org/issue?@action=redirect&bpo=31243]: Fix a crash in some methods of io.TextIOWrapper, when the decoder’s state is invalid. Patch by Oren Milman.

bpo-30721 [https://bugs.python.org/issue?@action=redirect&bpo=30721]: print now shows correct usage hint for using Python 2 redirection syntax. Patch by Sanyam Khurana.

bpo-31070 [https://bugs.python.org/issue?@action=redirect&bpo=31070]: Fix a race condition in importlib _get_module_lock().

bpo-30747 [https://bugs.python.org/issue?@action=redirect&bpo=30747]: Add a non-dummy implementation of _Py_atomic_store and _Py_atomic_load on MSVC.

bpo-31095 [https://bugs.python.org/issue?@action=redirect&bpo=31095]: Fix potential crash during GC caused by tp_dealloc which doesn’t call PyObject_GC_UnTrack().

bpo-31071 [https://bugs.python.org/issue?@action=redirect&bpo=31071]: Avoid masking original TypeError in call with * unpacking when other arguments are passed.

bpo-30978 [https://bugs.python.org/issue?@action=redirect&bpo=30978]: str.format_map() now passes key lookup exceptions through. Previously any exception was replaced with a KeyError exception.

bpo-30808 [https://bugs.python.org/issue?@action=redirect&bpo=30808]: Use _Py_atomic API for concurrency-sensitive signal state.

bpo-30876 [https://bugs.python.org/issue?@action=redirect&bpo=30876]: Relative import from unloaded package now reimports the package instead of failing with SystemError. Relative import from non-package now fails with ImportError rather than SystemError.

bpo-30703 [https://bugs.python.org/issue?@action=redirect&bpo=30703]: Improve signal delivery. Avoid using Py_AddPendingCall from signal handler, to avoid calling signal-unsafe functions. The tests I’m adding here fail without the rest of the patch, on Linux and OS X. This means our signal delivery logic had defects (some signals could be lost).

bpo-30765 [https://bugs.python.org/issue?@action=redirect&bpo=30765]: Avoid blocking in pthread_mutex_lock() when PyThread_acquire_lock() is asked not to block.

bpo-31161 [https://bugs.python.org/issue?@action=redirect&bpo=31161]: Make sure the ‘Missing parentheses’ syntax error message is only applied to SyntaxError, not to subclasses. Patch by Martijn Pieters.

bpo-30814 [https://bugs.python.org/issue?@action=redirect&bpo=30814]: Fixed a race condition when import a submodule from a package.

bpo-30736 [https://bugs.python.org/issue?@action=redirect&bpo=30736]: The internal unicodedata database has been upgraded to Unicode 10.0.

bpo-30604 [https://bugs.python.org/issue?@action=redirect&bpo=30604]: Move co_extra_freefuncs from per-thread to per-interpreter to avoid crashes.

bpo-30597 [https://bugs.python.org/issue?@action=redirect&bpo=30597]: print now shows expected input in custom error message when used as a Python 2 statement. Patch by Sanyam Khurana.

bpo-30682 [https://bugs.python.org/issue?@action=redirect&bpo=30682]: Removed a too-strict assertion that failed for certain f-strings, such as eval(“f’\n’”) and eval(“f’\r’”).

bpo-30501 [https://bugs.python.org/issue?@action=redirect&bpo=30501]: The compiler now produces more optimal code for complex condition expressions in the “if”, “while” and “assert” statement, the “if” expression, and generator expressions and comprehensions.

bpo-28180 [https://bugs.python.org/issue?@action=redirect&bpo=28180]: Implement PEP 538 [https://peps.python.org/pep-0538/] (legacy C locale coercion). This means that when a suitable coercion target locale is available, both the core interpreter and locale-aware C extensions will assume the use of UTF-8 as the default text encoding, rather than ASCII.

bpo-30486 [https://bugs.python.org/issue?@action=redirect&bpo=30486]: Allows setting cell values for __closure__. Patch by Lisa Roach.

bpo-30537 [https://bugs.python.org/issue?@action=redirect&bpo=30537]: itertools.islice now accepts integer-like objects (having an __index__ method) as start, stop, and slice arguments

bpo-25324 [https://bugs.python.org/issue?@action=redirect&bpo=25324]: Tokens needed for parsing in Python moved to C. COMMENT, NL and ENCODING. This way the tokens and tok_names in the token module don’t get changed when you import the tokenize module.

bpo-29104 [https://bugs.python.org/issue?@action=redirect&bpo=29104]: Fixed parsing backslashes in f-strings.

bpo-27945 [https://bugs.python.org/issue?@action=redirect&bpo=27945]: Fixed various segfaults with dict when input collections are mutated during searching, inserting or comparing. Based on patches by Duane Griffin and Tim Mitchell.

bpo-25794 [https://bugs.python.org/issue?@action=redirect&bpo=25794]: Fixed type.__setattr__() and type.__delattr__() for non-interned attribute names. Based on patch by Eryk Sun.

bpo-30039 [https://bugs.python.org/issue?@action=redirect&bpo=30039]: If a KeyboardInterrupt happens when the interpreter is in the middle of resuming a chain of nested ‘yield from’ or ‘await’ calls, it’s now correctly delivered to the innermost frame.

bpo-28974 [https://bugs.python.org/issue?@action=redirect&bpo=28974]: object.__format__(x, '') is now equivalent to str(x) rather than format(str(self), '').

bpo-30024 [https://bugs.python.org/issue?@action=redirect&bpo=30024]: Circular imports involving absolute imports with binding a submodule to a name are now supported.

bpo-12414 [https://bugs.python.org/issue?@action=redirect&bpo=12414]: sys.getsizeof() on a code object now returns the sizes which includes the code struct and sizes of objects which it references. Patch by Donghee Na.

bpo-29839 [https://bugs.python.org/issue?@action=redirect&bpo=29839]: len() now raises ValueError rather than OverflowError if __len__() returned a large negative integer.

bpo-11913 [https://bugs.python.org/issue?@action=redirect&bpo=11913]: README.rst is now included in the list of distutils standard READMEs and therefore included in source distributions.

bpo-29914 [https://bugs.python.org/issue?@action=redirect&bpo=29914]: Fixed default implementations of __reduce__ and __reduce_ex__(). object.__reduce__() no longer takes arguments, object.__reduce_ex__() now requires one argument.

bpo-29949 [https://bugs.python.org/issue?@action=redirect&bpo=29949]: Fix memory usage regression of set and frozenset object.

bpo-29935 [https://bugs.python.org/issue?@action=redirect&bpo=29935]: Fixed error messages in the index() method of tuple, list and deque when pass indices of wrong type.

bpo-29816 [https://bugs.python.org/issue?@action=redirect&bpo=29816]: Shift operation now has less opportunity to raise OverflowError. ValueError always is raised rather than OverflowError for negative counts. Shifting zero with non-negative count always returns zero.

bpo-24821 [https://bugs.python.org/issue?@action=redirect&bpo=24821]: Fixed the slowing down to 25 times in the searching of some unlucky Unicode characters.

bpo-29102 [https://bugs.python.org/issue?@action=redirect&bpo=29102]: Add a unique ID to PyInterpreterState. This makes it easier to identify each subinterpreter.

bpo-29894 [https://bugs.python.org/issue?@action=redirect&bpo=29894]: The deprecation warning is emitted if __complex__ returns an instance of a strict subclass of complex. In a future versions of Python this can be an error.

bpo-29859 [https://bugs.python.org/issue?@action=redirect&bpo=29859]: Show correct error messages when any of the pthread_* calls in thread_pthread.h fails.

bpo-29849 [https://bugs.python.org/issue?@action=redirect&bpo=29849]: Fix a memory leak when an ImportError is raised during from import.

bpo-28856 [https://bugs.python.org/issue?@action=redirect&bpo=28856]: Fix an oversight that %b format for bytes should support objects follow the buffer protocol.

bpo-29723 [https://bugs.python.org/issue?@action=redirect&bpo=29723]: The sys.path[0] initialization change for bpo-29139 [https://bugs.python.org/issue?@action=redirect&bpo=29139] caused a regression by revealing an inconsistency in how sys.path is initialized when executing __main__ from a zipfile, directory, or other import location. The interpreter now consistently avoids ever adding the import location’s parent directory to sys.path, and ensures no other sys.path entries are inadvertently modified when inserting the import location named on the command line.

bpo-29568 [https://bugs.python.org/issue?@action=redirect&bpo=29568]: Escaped percent “%%” in the format string for classic string formatting no longer allows any characters between two percents.

bpo-29714 [https://bugs.python.org/issue?@action=redirect&bpo=29714]: Fix a regression that bytes format may fail when containing zero bytes inside.

bpo-29695 [https://bugs.python.org/issue?@action=redirect&bpo=29695]: bool(), float(), list() and tuple() no longer take keyword arguments. The first argument of int() can now be passes only as positional argument.

bpo-28893 [https://bugs.python.org/issue?@action=redirect&bpo=28893]: Set correct __cause__ for errors about invalid awaitables returned from __aiter__ and __anext__.

bpo-28876 [https://bugs.python.org/issue?@action=redirect&bpo=28876]: bool(range) works even if len(range) raises OverflowError.

bpo-29683 [https://bugs.python.org/issue?@action=redirect&bpo=29683]: Fixes to memory allocation in _PyCode_SetExtra. Patch by Brian Coleman.

bpo-29684 [https://bugs.python.org/issue?@action=redirect&bpo=29684]: Fix minor regression of PyEval_CallObjectWithKeywords. It should raise TypeError when kwargs is not a dict. But it might cause segv when args=NULL and kwargs is not a dict.

bpo-28598 [https://bugs.python.org/issue?@action=redirect&bpo=28598]: Support __rmod__ for subclasses of str being called before str.__mod__. Patch by Martijn Pieters.

bpo-29607 [https://bugs.python.org/issue?@action=redirect&bpo=29607]: Fix stack_effect computation for CALL_FUNCTION_EX. Patch by Matthieu Dartiailh.

bpo-29602 [https://bugs.python.org/issue?@action=redirect&bpo=29602]: Fix incorrect handling of signed zeros in complex constructor for complex subclasses and for inputs having a __complex__ method. Patch by Serhiy Storchaka.

bpo-29347 [https://bugs.python.org/issue?@action=redirect&bpo=29347]: Fixed possibly dereferencing undefined pointers when creating weakref objects.

bpo-29463 [https://bugs.python.org/issue?@action=redirect&bpo=29463]: Add docstring field to Module, ClassDef, FunctionDef, and AsyncFunctionDef ast nodes. docstring is not first stmt in their body anymore. It affects co_firstlineno and co_lnotab of code object for module and class. (Reverted in bpo-32911 [https://bugs.python.org/issue?@action=redirect&bpo=32911].)

bpo-29438 [https://bugs.python.org/issue?@action=redirect&bpo=29438]: Fixed use-after-free problem in key sharing dict.

bpo-29546 [https://bugs.python.org/issue?@action=redirect&bpo=29546]: Set the ‘path’ and ‘name’ attribute on ImportError for from ... import ....

bpo-29546 [https://bugs.python.org/issue?@action=redirect&bpo=29546]: Improve from-import error message with location

bpo-29478 [https://bugs.python.org/issue?@action=redirect&bpo=29478]: If max_line_length=None is specified while using the Compat32 policy, it is no longer ignored. Patch by Mircea Cosbuc.

bpo-29319 [https://bugs.python.org/issue?@action=redirect&bpo=29319]: Prevent RunMainFromImporter overwriting sys.path[0].

bpo-29337 [https://bugs.python.org/issue?@action=redirect&bpo=29337]: Fixed possible BytesWarning when compare the code objects. Warnings could be emitted at compile time.

bpo-29327 [https://bugs.python.org/issue?@action=redirect&bpo=29327]: Fixed a crash when pass the iterable keyword argument to sorted().

bpo-29034 [https://bugs.python.org/issue?@action=redirect&bpo=29034]: Fix memory leak and use-after-free in os module (path_converter).

bpo-29159 [https://bugs.python.org/issue?@action=redirect&bpo=29159]: Fix regression in bytes(x) when x.__index__() raises Exception.

bpo-29049 [https://bugs.python.org/issue?@action=redirect&bpo=29049]: Call _PyObject_GC_TRACK() lazily when calling Python function. Calling function is up to 5% faster.

bpo-28927 [https://bugs.python.org/issue?@action=redirect&bpo=28927]: bytes.fromhex() and bytearray.fromhex() now ignore all ASCII whitespace, not only spaces. Patch by Robert Xiao.

bpo-28932 [https://bugs.python.org/issue?@action=redirect&bpo=28932]: Do not include <sys/random.h> if it does not exist.

bpo-25677 [https://bugs.python.org/issue?@action=redirect&bpo=25677]: Correct the positioning of the syntax error caret for indented blocks. Based on patch by Michael Layzell.

bpo-29000 [https://bugs.python.org/issue?@action=redirect&bpo=29000]: Fixed bytes formatting of octals with zero padding in alternate form.

bpo-18896 [https://bugs.python.org/issue?@action=redirect&bpo=18896]: Python function can now have more than 255 parameters. collections.namedtuple() now supports tuples with more than 255 elements.

bpo-28596 [https://bugs.python.org/issue?@action=redirect&bpo=28596]: The preferred encoding is UTF-8 on Android. Patch written by Chi Hsuan Yen.

bpo-22257 [https://bugs.python.org/issue?@action=redirect&bpo=22257]: Clean up interpreter startup (see PEP 432 [https://peps.python.org/pep-0432/]).

bpo-26919 [https://bugs.python.org/issue?@action=redirect&bpo=26919]: On Android, operating system data is now always encoded/decoded to/from UTF-8, instead of the locale encoding to avoid inconsistencies with os.fsencode() and os.fsdecode() which are already using UTF-8.

bpo-28991 [https://bugs.python.org/issue?@action=redirect&bpo=28991]: functools.lru_cache() was susceptible to an obscure reentrancy bug triggerable by a monkey-patched len() function.

bpo-28147 [https://bugs.python.org/issue?@action=redirect&bpo=28147]: Fix a memory leak in split-table dictionaries: setattr() must not convert combined table into split table. Patch written by INADA Naoki.

bpo-28739 [https://bugs.python.org/issue?@action=redirect&bpo=28739]: f-string expressions are no longer accepted as docstrings and by ast.literal_eval() even if they do not include expressions.

bpo-28512 [https://bugs.python.org/issue?@action=redirect&bpo=28512]: Fixed setting the offset attribute of SyntaxError by PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

bpo-28918 [https://bugs.python.org/issue?@action=redirect&bpo=28918]: Fix the cross compilation of xxlimited when Python has been built with Py_DEBUG defined.

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: Rather than silently producing a class that doesn’t support zero-argument super() in methods, failing to pass the new __classcell__ namespace entry up to type.__new__ now results in a DeprecationWarning and a class that supports zero-argument super().

bpo-28797 [https://bugs.python.org/issue?@action=redirect&bpo=28797]: Modifying the class __dict__ inside the __set_name__ method of a descriptor that is used inside that class no longer prevents calling the __set_name__ method of other descriptors.

bpo-28799 [https://bugs.python.org/issue?@action=redirect&bpo=28799]: Remove the PyEval_GetCallStats() function and deprecate the untested and undocumented sys.callstats() function. Remove the CALL_PROFILE special build: use the sys.setprofile() function, cProfile or profile to profile function calls.

bpo-12844 [https://bugs.python.org/issue?@action=redirect&bpo=12844]: More than 255 arguments can now be passed to a function.

bpo-28782 [https://bugs.python.org/issue?@action=redirect&bpo=28782]: Fix a bug in the implementation yield from when checking if the next instruction is YIELD_FROM. Regression introduced by WORDCODE (bpo-26647 [https://bugs.python.org/issue?@action=redirect&bpo=26647]).

bpo-28774 [https://bugs.python.org/issue?@action=redirect&bpo=28774]: Fix error position of the unicode error in ASCII and Latin1 encoders when a string returned by the error handler contains multiple non-encodable characters (non-ASCII for the ASCII codec, characters out of the U+0000-U+00FF range for Latin1).

bpo-28731 [https://bugs.python.org/issue?@action=redirect&bpo=28731]: Optimize _PyDict_NewPresized() to create correct size dict. Improve speed of dict literal with constant keys up to 30%.

bpo-28532 [https://bugs.python.org/issue?@action=redirect&bpo=28532]: Show sys.version when -V option is supplied twice.

bpo-27100 [https://bugs.python.org/issue?@action=redirect&bpo=27100]: The with-statement now checks for __enter__ before it checks for __exit__. This gives less confusing error messages when both methods are missing. Patch by Jonathan Ellington.

bpo-28746 [https://bugs.python.org/issue?@action=redirect&bpo=28746]: Fix the set_inheritable() file descriptor method on platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

bpo-26920 [https://bugs.python.org/issue?@action=redirect&bpo=26920]: Fix not getting the locale’s charset upon initializing the interpreter, on platforms that do not have langinfo.

bpo-28648 [https://bugs.python.org/issue?@action=redirect&bpo=28648]: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X when decode astral characters. Patch by Xiang Zhang.

bpo-28665 [https://bugs.python.org/issue?@action=redirect&bpo=28665]: Improve speed of the STORE_DEREF opcode by 40%.

bpo-19398 [https://bugs.python.org/issue?@action=redirect&bpo=19398]: Extra slash no longer added to sys.path components in case of empty compile-time PYTHONPATH components.

bpo-28621 [https://bugs.python.org/issue?@action=redirect&bpo=28621]: Sped up converting int to float by reusing faster bits counting implementation. Patch by Adrian Wielgosik.

bpo-28580 [https://bugs.python.org/issue?@action=redirect&bpo=28580]: Optimize iterating split table values. Patch by Xiang Zhang.

bpo-28583 [https://bugs.python.org/issue?@action=redirect&bpo=28583]: PyDict_SetDefault didn’t combine split table when needed. Patch by Xiang Zhang.

bpo-28128 [https://bugs.python.org/issue?@action=redirect&bpo=28128]: Deprecation warning for invalid str and byte escape sequences now prints better information about where the error occurs. Patch by Serhiy Storchaka and Eric Smith.

bpo-28509 [https://bugs.python.org/issue?@action=redirect&bpo=28509]: dict.update() no longer allocate unnecessary large memory.

bpo-28426 [https://bugs.python.org/issue?@action=redirect&bpo=28426]: Fixed potential crash in PyUnicode_AsDecodedObject() in debug build.

bpo-28517 [https://bugs.python.org/issue?@action=redirect&bpo=28517]: Fixed of-by-one error in the peephole optimizer that caused keeping unreachable code.

bpo-28214 [https://bugs.python.org/issue?@action=redirect&bpo=28214]: Improved exception reporting for problematic __set_name__ attributes.

bpo-23782 [https://bugs.python.org/issue?@action=redirect&bpo=23782]: Fixed possible memory leak in _PyTraceback_Add() and exception loss in PyTraceBack_Here().

bpo-28183 [https://bugs.python.org/issue?@action=redirect&bpo=28183]: Optimize and cleanup dict iteration.

bpo-26081 [https://bugs.python.org/issue?@action=redirect&bpo=26081]: Added C implementation of asyncio.Future. Original patch by Yury Selivanov.

bpo-28379 [https://bugs.python.org/issue?@action=redirect&bpo=28379]: Added sanity checks and tests for PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: The type of long range iterator is now registered as Iterator. Patch by Oren Milman.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: Creating instances of range_iterator by calling range_iterator type now is disallowed. Calling iter() on range instance is the only way. Patch by Oren Milman.

bpo-26906 [https://bugs.python.org/issue?@action=redirect&bpo=26906]: Resolving special methods of uninitialized type now causes implicit initialization of the type instead of a fail.

bpo-18287 [https://bugs.python.org/issue?@action=redirect&bpo=18287]: PyType_Ready() now checks that tp_name is not NULL. Original patch by Niklas Koep.

bpo-24098 [https://bugs.python.org/issue?@action=redirect&bpo=24098]: Fixed possible crash when AST is changed in process of compiling it.

bpo-28201 [https://bugs.python.org/issue?@action=redirect&bpo=28201]: Dict reduces possibility of 2nd conflict in hash table when hashes have same lower bits.

bpo-28350 [https://bugs.python.org/issue?@action=redirect&bpo=28350]: String constants with null character no longer interned.

bpo-26617 [https://bugs.python.org/issue?@action=redirect&bpo=26617]: Fix crash when GC runs during weakref callbacks.

bpo-27942 [https://bugs.python.org/issue?@action=redirect&bpo=27942]: String constants now interned recursively in tuples and frozensets.

bpo-28289 [https://bugs.python.org/issue?@action=redirect&bpo=28289]: ImportError.__init__ now resets not specified attributes.

bpo-21578 [https://bugs.python.org/issue?@action=redirect&bpo=21578]: Fixed misleading error message when ImportError called with invalid keyword args.

bpo-28203 [https://bugs.python.org/issue?@action=redirect&bpo=28203]: Fix incorrect type in complex(1.0, {2:3}) error message. Patch by Soumya Sharma.

bpo-28086 [https://bugs.python.org/issue?@action=redirect&bpo=28086]: Single var-positional argument of tuple subtype was passed unscathed to the C-defined function. Now it is converted to exact tuple.

bpo-28214 [https://bugs.python.org/issue?@action=redirect&bpo=28214]: Now __set_name__ is looked up on the class instead of the instance.

bpo-27955 [https://bugs.python.org/issue?@action=redirect&bpo=27955]: Fallback on reading /dev/urandom device when the getrandom() syscall fails with EPERM, for example when blocked by SECCOMP.

bpo-28192 [https://bugs.python.org/issue?@action=redirect&bpo=28192]: Don’t import readline in isolated mode.

bpo-27441 [https://bugs.python.org/issue?@action=redirect&bpo=27441]: Remove some redundant assignments to ob_size in longobject.c. Thanks Oren Milman.

bpo-27222 [https://bugs.python.org/issue?@action=redirect&bpo=27222]: Clean up redundant code in long_rshift function. Thanks Oren Milman.

Upgrade internal unicode databases to Unicode version 9.0.0.

bpo-28131 [https://bugs.python.org/issue?@action=redirect&bpo=28131]: Fix a regression in zipimport’s compile_source(). zipimport should use the same optimization level as the interpreter.

bpo-28126 [https://bugs.python.org/issue?@action=redirect&bpo=28126]: Replace Py_MEMCPY with memcpy(). Visual Studio can properly optimize memcpy().

bpo-28120 [https://bugs.python.org/issue?@action=redirect&bpo=28120]: Fix dict.pop() for split dictionary when trying to remove a “pending key” (Not yet inserted in split-table). Patch by Xiang Zhang.

bpo-26182 [https://bugs.python.org/issue?@action=redirect&bpo=26182]: Raise DeprecationWarning when async and await keywords are used as variable/attribute/class/function name.

bpo-26182 [https://bugs.python.org/issue?@action=redirect&bpo=26182]: Fix a refleak in code that raises DeprecationWarning.

bpo-28721 [https://bugs.python.org/issue?@action=redirect&bpo=28721]: Fix asynchronous generators aclose() and athrow() to handle StopAsyncIteration propagation properly.

bpo-26110 [https://bugs.python.org/issue?@action=redirect&bpo=26110]: Speed-up method calls: add LOAD_METHOD and CALL_METHOD opcodes.

Library

bpo-31499 [https://bugs.python.org/issue?@action=redirect&bpo=31499]: xml.etree: Fix a crash when a parser is part of a reference cycle.

bpo-31482 [https://bugs.python.org/issue?@action=redirect&bpo=31482]: random.seed() now works with bytes in version=1

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: typing.get_type_hints now finds the right globalns for classes and modules by default (when no globalns was specified by the caller).

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Speed improvements to the typing module. Original PRs by Ivan Levkivskyi and Mitar.

bpo-31544 [https://bugs.python.org/issue?@action=redirect&bpo=31544]: The C accelerator module of ElementTree ignored exceptions raised when looking up TreeBuilder target methods in XMLParser().

bpo-31234 [https://bugs.python.org/issue?@action=redirect&bpo=31234]: socket.create_connection() now fixes manually a reference cycle: clear the variable storing the last exception on success.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: LoggerAdapter objects can now be nested.

bpo-31431 [https://bugs.python.org/issue?@action=redirect&bpo=31431]: SSLContext.check_hostname now automatically sets SSLContext.verify_mode to ssl.CERT_REQUIRED instead of failing with a ValueError.

bpo-31233 [https://bugs.python.org/issue?@action=redirect&bpo=31233]: socketserver.ThreadingMixIn now keeps a list of non-daemonic threads to wait until all these threads complete in server_close().

bpo-28638 [https://bugs.python.org/issue?@action=redirect&bpo=28638]: Changed the implementation strategy for collections.namedtuple() to substantially reduce the use of exec() in favor of precomputed methods. As a result, the verbose parameter and _source attribute are no longer supported. The benefits include 1) having a smaller memory footprint for applications using multiple named tuples, 2) faster creation of the named tuple class (approx 4x to 6x depending on how it is measured), and 3) minor speed-ups for instance creation using __new__, _make, and _replace. (The primary patch contributor is Jelle Zijlstra with further improvements by INADA Naoki, Serhiy Storchaka, and Raymond Hettinger.)

bpo-31400 [https://bugs.python.org/issue?@action=redirect&bpo=31400]: Improves SSL error handling to avoid losing error numbers.

bpo-27629 [https://bugs.python.org/issue?@action=redirect&bpo=27629]: Make return types of SSLContext.wrap_bio() and SSLContext.wrap_socket() customizable.

bpo-28958 [https://bugs.python.org/issue?@action=redirect&bpo=28958]: ssl.SSLContext() now uses OpenSSL error information when a context cannot be instantiated.

bpo-28182 [https://bugs.python.org/issue?@action=redirect&bpo=28182]: The SSL module now raises SSLCertVerificationError when OpenSSL fails to verify the peer’s certificate. The exception contains more information about the error.

bpo-27340 [https://bugs.python.org/issue?@action=redirect&bpo=27340]: SSLSocket.sendall() now uses memoryview to create slices of data. This fixes support for all bytes-like object. It is also more efficient and avoids costly copies.

bpo-14191 [https://bugs.python.org/issue?@action=redirect&bpo=14191]: A new function argparse.ArgumentParser.parse_intermixed_args provides the ability to parse command lines where there user intermixes options and positional arguments.

bpo-31178 [https://bugs.python.org/issue?@action=redirect&bpo=31178]: Fix string concatenation bug in rare error path in the subprocess module

bpo-31350 [https://bugs.python.org/issue?@action=redirect&bpo=31350]: Micro-optimize asyncio._get_running_loop() to become up to 10% faster.

bpo-31170 [https://bugs.python.org/issue?@action=redirect&bpo=31170]: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying of partial characters for UTF-8 input (libexpat bug 115): https://github.com/libexpat/libexpat/issues/115

bpo-29136 [https://bugs.python.org/issue?@action=redirect&bpo=29136]: Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

bpo-1198569 [https://bugs.python.org/issue?@action=redirect&bpo=1198569]: string.Template subclasses can optionally define braceidpattern if they want to specify different placeholder patterns inside and outside the braces. If None (the default) it falls back to idpattern.

bpo-31326 [https://bugs.python.org/issue?@action=redirect&bpo=31326]: concurrent.futures.ProcessPoolExecutor.shutdown() now explicitly closes the call queue. Moreover, shutdown(wait=True) now also join the call queue thread, to prevent leaking a dangling thread.

bpo-27144 [https://bugs.python.org/issue?@action=redirect&bpo=27144]: The map() and as_completed() iterators in concurrent.futures now avoid keeping a reference to yielded objects.

bpo-31281 [https://bugs.python.org/issue?@action=redirect&bpo=31281]: Fix fileinput.FileInput(files, inplace=True) when files contain pathlib.Path objects.

bpo-10746 [https://bugs.python.org/issue?@action=redirect&bpo=10746]: Fix ctypes producing wrong PEP 3118 [https://peps.python.org/pep-3118/] type codes for integer types.

bpo-27584 [https://bugs.python.org/issue?@action=redirect&bpo=27584]: AF_VSOCK has been added to the socket interface which allows communication between virtual machines and their host.

bpo-22536 [https://bugs.python.org/issue?@action=redirect&bpo=22536]: The subprocess module now sets the filename when FileNotFoundError is raised on POSIX systems due to the executable or cwd not being found.

bpo-29741 [https://bugs.python.org/issue?@action=redirect&bpo=29741]: Update some methods in the _pyio module to also accept integer types. Patch by Oren Milman.

bpo-31249 [https://bugs.python.org/issue?@action=redirect&bpo=31249]: concurrent.futures: WorkItem.run() used by ThreadPoolExecutor now breaks a reference cycle between an exception object and the WorkItem object.

bpo-31247 [https://bugs.python.org/issue?@action=redirect&bpo=31247]: xmlrpc.server now explicitly breaks reference cycles when using sys.exc_info() in code handling exceptions.

bpo-23835 [https://bugs.python.org/issue?@action=redirect&bpo=23835]: configparser: reading defaults in the ConfigParser() constructor is now using read_dict(), making its behavior consistent with the rest of the parser. Non-string keys and values in the defaults dictionary are now being implicitly converted to strings. Patch by James Tocknell.

bpo-31238 [https://bugs.python.org/issue?@action=redirect&bpo=31238]: pydoc: the stop() method of the private ServerThread class now waits until DocServer.serve_until_quit() completes and then explicitly sets its docserver attribute to None to break a reference cycle.

bpo-5001 [https://bugs.python.org/issue?@action=redirect&bpo=5001]: Many asserts in multiprocessing are now more informative, and some error types have been changed to more specific ones.

bpo-31109 [https://bugs.python.org/issue?@action=redirect&bpo=31109]: Convert zipimport to use Argument Clinic.

bpo-30102 [https://bugs.python.org/issue?@action=redirect&bpo=30102]: The ssl and hashlib modules now call OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0. The function detects CPU features and enables optimizations on some CPU architectures such as POWER8. Patch is based on research from Gustavo Serra Scalet.

bpo-18966 [https://bugs.python.org/issue?@action=redirect&bpo=18966]: Non-daemonic threads created by a multiprocessing.Process are now joined on child exit.

bpo-31183 [https://bugs.python.org/issue?@action=redirect&bpo=31183]: dis now works with asynchronous generator and coroutine objects. Patch by George Collins based on diagnosis by Luciano Ramalho.

bpo-5001 [https://bugs.python.org/issue?@action=redirect&bpo=5001]: There are a number of uninformative asserts in the multiprocessing module, as noted in issue 5001. This change fixes two of the most potentially problematic ones, since they are in error-reporting code, in the multiprocessing.managers.convert_to_error function. (It also makes more informative a ValueError message.) The only potentially problematic change is that the AssertionError is now a TypeError; however, this should also help distinguish it from an AssertionError being reported by the function/its caller (such as in issue 31169). - Patch by Allen W. Smith (drallensmith on github).

bpo-31185 [https://bugs.python.org/issue?@action=redirect&bpo=31185]: Fixed miscellaneous errors in asyncio speedup module.

bpo-31151 [https://bugs.python.org/issue?@action=redirect&bpo=31151]: socketserver.ForkingMixIn.server_close() now waits until all child processes completed to prevent leaking zombie processes.

bpo-31072 [https://bugs.python.org/issue?@action=redirect&bpo=31072]: Add an include_file parameter to zipapp.create_archive()

bpo-24700 [https://bugs.python.org/issue?@action=redirect&bpo=24700]: Optimize array.array comparison. It is now from 10x up to 70x faster when comparing arrays holding values of the same integer type.

bpo-31135 [https://bugs.python.org/issue?@action=redirect&bpo=31135]: ttk: fix the destroy() method of LabeledScale and OptionMenu classes. Call the parent destroy() method even if the used attribute doesn’t exist. The LabeledScale.destroy() method now also explicitly clears label and scale attributes to help the garbage collector to destroy all widgets.

bpo-31107 [https://bugs.python.org/issue?@action=redirect&bpo=31107]: Fix copyreg._slotnames() mangled attribute calculation for classes whose name begins with an underscore. Patch by Shane Harvey.

bpo-31080 [https://bugs.python.org/issue?@action=redirect&bpo=31080]: Allow logging.config.fileConfig to accept kwargs and/or args.

bpo-30897 [https://bugs.python.org/issue?@action=redirect&bpo=30897]: pathlib.Path objects now include an is_mount() method (only implemented on POSIX). This is similar to os.path.ismount(p). Patch by Cooper Ry Lees.

bpo-31061 [https://bugs.python.org/issue?@action=redirect&bpo=31061]: Fixed a crash when using asyncio and threads.

bpo-30987 [https://bugs.python.org/issue?@action=redirect&bpo=30987]: Added support for CAN ISO-TP protocol in the socket module.

bpo-30522 [https://bugs.python.org/issue?@action=redirect&bpo=30522]: Added a setStream method to logging.StreamHandler to allow the stream to be set after creation.

bpo-30502 [https://bugs.python.org/issue?@action=redirect&bpo=30502]: Fix handling of long oids in ssl. Based on patch by Christian Heimes.

bpo-5288 [https://bugs.python.org/issue?@action=redirect&bpo=5288]: Support tzinfo objects with sub-minute offsets.

bpo-30919 [https://bugs.python.org/issue?@action=redirect&bpo=30919]: Fix shared memory performance regression in multiprocessing in 3.x. Shared memory used anonymous memory mappings in 2.x, while 3.x mmaps actual files. Try to be careful to do as little disk I/O as possible.

bpo-26732 [https://bugs.python.org/issue?@action=redirect&bpo=26732]: Fix too many fds in processes started with the “forkserver” method. A child process would inherit as many fds as the number of still-running children.

bpo-29403 [https://bugs.python.org/issue?@action=redirect&bpo=29403]: Fix unittest.mock’s autospec to not fail on method-bound builtin functions. Patch by Aaron Gallagher.

bpo-30961 [https://bugs.python.org/issue?@action=redirect&bpo=30961]: Fix decrementing a borrowed reference in tracemalloc.

bpo-19896 [https://bugs.python.org/issue?@action=redirect&bpo=19896]: Fix multiprocessing.sharedctypes to recognize typecodes 'q' and 'Q'.

bpo-30946 [https://bugs.python.org/issue?@action=redirect&bpo=30946]: Remove obsolete code in readline module for platforms where GNU readline is older than 2.1 or where select() is not available.

bpo-25684 [https://bugs.python.org/issue?@action=redirect&bpo=25684]: Change ttk.OptionMenu radiobuttons to be unique across instances of OptionMenu.

bpo-30886 [https://bugs.python.org/issue?@action=redirect&bpo=30886]: Fix multiprocessing.Queue.join_thread(): it now waits until the thread completes, even if the thread was started by the same process which created the queue.

bpo-29854 [https://bugs.python.org/issue?@action=redirect&bpo=29854]: Fix segfault in readline when using readline’s history-size option. Patch by Nir Soffer.

bpo-30794 [https://bugs.python.org/issue?@action=redirect&bpo=30794]: Added multiprocessing.Process.kill method to terminate using the SIGKILL signal on Unix.

bpo-30319 [https://bugs.python.org/issue?@action=redirect&bpo=30319]: socket.close() now ignores ECONNRESET error.

bpo-30828 [https://bugs.python.org/issue?@action=redirect&bpo=30828]: Fix out of bounds write in asyncio.CFuture.remove_done_callback().

bpo-30302 [https://bugs.python.org/issue?@action=redirect&bpo=30302]: Use keywords in the repr of datetime.timedelta.

bpo-30807 [https://bugs.python.org/issue?@action=redirect&bpo=30807]: signal.setitimer() may disable the timer when passed a tiny value. Tiny values (such as 1e-6) are valid non-zero values for setitimer(), which is specified as taking microsecond-resolution intervals. However, on some platform, our conversion routine could convert 1e-6 into a zero interval, therefore disabling the timer instead of (re-)scheduling it.

bpo-30441 [https://bugs.python.org/issue?@action=redirect&bpo=30441]: Fix bug when modifying os.environ while iterating over it

bpo-29585 [https://bugs.python.org/issue?@action=redirect&bpo=29585]: Avoid importing sysconfig from site to improve startup speed. Python startup is about 5% faster on Linux and 30% faster on macOS.

bpo-29293 [https://bugs.python.org/issue?@action=redirect&bpo=29293]: Add missing parameter “n” on multiprocessing.Condition.notify(). The doc claims multiprocessing.Condition behaves like threading.Condition, but its notify() method lacked the optional “n” argument (to specify the number of sleepers to wake up) that threading.Condition.notify() accepts.

bpo-30532 [https://bugs.python.org/issue?@action=redirect&bpo=30532]: Fix email header value parser dropping folding white space in certain cases.

bpo-30596 [https://bugs.python.org/issue?@action=redirect&bpo=30596]: Add a close() method to multiprocessing.Process.

bpo-9146 [https://bugs.python.org/issue?@action=redirect&bpo=9146]: Fix a segmentation fault in _hashopenssl when standard hash functions such as md5 are not available in the linked OpenSSL library. As in some special FIPS-140 build environments.

bpo-29169 [https://bugs.python.org/issue?@action=redirect&bpo=29169]: Update zlib to 1.2.11.

bpo-30119 [https://bugs.python.org/issue?@action=redirect&bpo=30119]: ftplib.FTP.putline() now throws ValueError on commands that contains CR or LF. Patch by Donghee Na.

bpo-30879 [https://bugs.python.org/issue?@action=redirect&bpo=30879]: os.listdir() and os.scandir() now emit bytes names when called with bytes-like argument.

bpo-30746 [https://bugs.python.org/issue?@action=redirect&bpo=30746]: Prohibited the ‘=’ character in environment variable names in os.putenv() and os.spawn*().

bpo-30664 [https://bugs.python.org/issue?@action=redirect&bpo=30664]: The description of a unittest subtest now preserves the order of keyword arguments of TestCase.subTest().

bpo-21071 [https://bugs.python.org/issue?@action=redirect&bpo=21071]: struct.Struct.format type is now str instead of bytes.

bpo-29212 [https://bugs.python.org/issue?@action=redirect&bpo=29212]: Fix concurrent.futures.thread.ThreadPoolExecutor threads to have a non repr() based thread name by default when no thread_name_prefix is supplied. They will now identify themselves as “ThreadPoolExecutor-y_n”.

bpo-29755 [https://bugs.python.org/issue?@action=redirect&bpo=29755]: Fixed the lgettext() family of functions in the gettext module. They now always return bytes.

bpo-30616 [https://bugs.python.org/issue?@action=redirect&bpo=30616]: Functional API of enum allows to create empty enums. Patched by Donghee Na

bpo-30038 [https://bugs.python.org/issue?@action=redirect&bpo=30038]: Fix race condition between signal delivery and wakeup file descriptor. Patch by Nathaniel Smith.

bpo-23894 [https://bugs.python.org/issue?@action=redirect&bpo=23894]: lib2to3 now recognizes rb'...' and f'...' strings.

bpo-24744 [https://bugs.python.org/issue?@action=redirect&bpo=24744]: pkgutil.walk_packages function now raises ValueError if path is a string. Patch by Sanyam Khurana.

bpo-24484 [https://bugs.python.org/issue?@action=redirect&bpo=24484]: Avoid race condition in multiprocessing cleanup.

bpo-30589 [https://bugs.python.org/issue?@action=redirect&bpo=30589]: Fix multiprocessing.Process.exitcode to return the opposite of the signal number when the process is killed by a signal (instead of 255) when using the “forkserver” method.

bpo-28994 [https://bugs.python.org/issue?@action=redirect&bpo=28994]: The traceback no longer displayed for SystemExit raised in a callback registered by atexit.

bpo-30508 [https://bugs.python.org/issue?@action=redirect&bpo=30508]: Don’t log exceptions if Task/Future “cancel()” method was called.

bpo-30645 [https://bugs.python.org/issue?@action=redirect&bpo=30645]: Fix path calculation in imp.load_package(), fixing it for cases when a package is only shipped with bytecodes. Patch by Alexandru Ardelean.

bpo-11822 [https://bugs.python.org/issue?@action=redirect&bpo=11822]: The dis.dis() function now is able to disassemble nested code objects.

bpo-30624 [https://bugs.python.org/issue?@action=redirect&bpo=30624]: selectors does not take KeyboardInterrupt and SystemExit into account, leaving a fd in a bad state in case of error. Patch by Giampaolo Rodola’.

bpo-30595 [https://bugs.python.org/issue?@action=redirect&bpo=30595]: multiprocessing.Queue.get() with a timeout now polls its reader in non-blocking mode if it succeeded to acquire the lock but the acquire took longer than the timeout.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Updates to typing module: Add generic AsyncContextManager, add support for ContextManager on all versions. Original PRs by Jelle Zijlstra and Ivan Levkivskyi

bpo-30605 [https://bugs.python.org/issue?@action=redirect&bpo=30605]: re.compile() no longer raises a BytesWarning when compiling a bytes instance with misplaced inline modifier. Patch by Roy Williams.

bpo-29870 [https://bugs.python.org/issue?@action=redirect&bpo=29870]: Fix ssl sockets leaks when connection is aborted in asyncio/ssl implementation. Patch by Michaël Sghaïer.

bpo-29743 [https://bugs.python.org/issue?@action=redirect&bpo=29743]: Closing transport during handshake process leaks open socket. Patch by Nikolay Kim

bpo-27585 [https://bugs.python.org/issue?@action=redirect&bpo=27585]: Fix waiter cancellation in asyncio.Lock. Patch by Mathieu Sornay.

bpo-30014 [https://bugs.python.org/issue?@action=redirect&bpo=30014]: modify() method of poll(), epoll() and devpoll() based classes of selectors module is around 10% faster. Patch by Giampaolo Rodola’.

bpo-30418 [https://bugs.python.org/issue?@action=redirect&bpo=30418]: On Windows, subprocess.Popen.communicate() now also ignore EINVAL on stdin.write() if the child process is still running but closed the pipe.

bpo-30463 [https://bugs.python.org/issue?@action=redirect&bpo=30463]: Added empty __slots__ to abc.ABC. This allows subclassers to deny __dict__ and __weakref__ creation. Patch by Aaron Hall.

bpo-30520 [https://bugs.python.org/issue?@action=redirect&bpo=30520]: Loggers are now pickleable.

bpo-30557 [https://bugs.python.org/issue?@action=redirect&bpo=30557]: faulthandler now correctly filters and displays exception codes on Windows

bpo-30526 [https://bugs.python.org/issue?@action=redirect&bpo=30526]: Add TextIOWrapper.reconfigure() and a TextIOWrapper.write_through attribute.

bpo-30245 [https://bugs.python.org/issue?@action=redirect&bpo=30245]: Fix possible overflow when organize struct.pack_into error message. Patch by Yuan Liu.

bpo-30378 [https://bugs.python.org/issue?@action=redirect&bpo=30378]: Fix the problem that logging.handlers.SysLogHandler cannot handle IPv6 addresses.

bpo-16500 [https://bugs.python.org/issue?@action=redirect&bpo=16500]: Allow registering at-fork handlers.

bpo-30470 [https://bugs.python.org/issue?@action=redirect&bpo=30470]: Deprecate invalid ctypes call protection on Windows. Patch by Mariatta Wijaya.

bpo-30414 [https://bugs.python.org/issue?@action=redirect&bpo=30414]: multiprocessing.Queue._feed background running thread do not break from main loop on exception.

bpo-30003 [https://bugs.python.org/issue?@action=redirect&bpo=30003]: Fix handling escape characters in HZ codec. Based on patch by Ma Lin.

bpo-30149 [https://bugs.python.org/issue?@action=redirect&bpo=30149]: inspect.signature() now supports callables with variable-argument parameters wrapped with partialmethod. Patch by Donghee Na.

bpo-30436 [https://bugs.python.org/issue?@action=redirect&bpo=30436]: importlib.find_spec() raises ModuleNotFoundError instead of AttributeError if the specified parent module is not a package (i.e. lacks a __path__ attribute).

bpo-30301 [https://bugs.python.org/issue?@action=redirect&bpo=30301]: Fix AttributeError when using SimpleQueue.empty() under spawn and forkserver start methods.

bpo-30375 [https://bugs.python.org/issue?@action=redirect&bpo=30375]: Warnings emitted when compile a regular expression now always point to the line in the user code. Previously they could point into inners of the re module if emitted from inside of groups or conditionals.

bpo-30329 [https://bugs.python.org/issue?@action=redirect&bpo=30329]: imaplib and poplib now catch the Windows socket WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid operation was attempted. This error occurs sometimes on SSL connections.

bpo-29196 [https://bugs.python.org/issue?@action=redirect&bpo=29196]: Removed previously deprecated in Python 2.4 classes Plist, Dict and _InternalDict in the plistlib module. Dict values in the result of functions readPlist() and readPlistFromBytes() are now normal dicts. You no longer can use attribute access to access items of these dictionaries.

bpo-9850 [https://bugs.python.org/issue?@action=redirect&bpo=9850]: The macpath is now deprecated and will be removed in Python 3.8.

bpo-30299 [https://bugs.python.org/issue?@action=redirect&bpo=30299]: Compiling regular expression in debug mode on CPython now displays the compiled bytecode in human readable form.

bpo-30048 [https://bugs.python.org/issue?@action=redirect&bpo=30048]: Fixed Task.cancel() can be ignored when the task is running coroutine and the coroutine returned without any more await.

bpo-30266 [https://bugs.python.org/issue?@action=redirect&bpo=30266]: contextlib.AbstractContextManager now supports anti-registration by setting __enter__ = None or __exit__ = None, following the pattern introduced in bpo-25958 [https://bugs.python.org/issue?@action=redirect&bpo=25958]. Patch by Jelle Zijlstra.

bpo-30340 [https://bugs.python.org/issue?@action=redirect&bpo=30340]: Enhanced regular expressions optimization. This increased the performance of matching some patterns up to 25 times.

bpo-30298 [https://bugs.python.org/issue?@action=redirect&bpo=30298]: Weaken the condition of deprecation warnings for inline modifiers. Now allowed several subsequential inline modifiers at the start of the pattern (e.g. '(?i)(?s)...'). In verbose mode whitespaces and comments now are allowed before and between inline modifiers (e.g. '(?x) (?i) (?s)...').

bpo-30285 [https://bugs.python.org/issue?@action=redirect&bpo=30285]: Optimized case-insensitive matching and searching of regular expressions.

bpo-29990 [https://bugs.python.org/issue?@action=redirect&bpo=29990]: Fix range checking in GB18030 decoder. Original patch by Ma Lin.

bpo-29979 [https://bugs.python.org/issue?@action=redirect&bpo=29979]: rewrite cgi.parse_multipart, reusing the FieldStorage class and making its results consistent with those of FieldStorage for multipart/form-data requests. Patch by Pierre Quentel.

bpo-30243 [https://bugs.python.org/issue?@action=redirect&bpo=30243]: Removed the __init__ methods of _json’s scanner and encoder. Misusing them could cause memory leaks or crashes. Now scanner and encoder objects are completely initialized in the __new__ methods.

bpo-30215 [https://bugs.python.org/issue?@action=redirect&bpo=30215]: Compiled regular expression objects with the re.LOCALE flag no longer depend on the locale at compile time. Only the locale at matching time affects the result of matching.

bpo-30185 [https://bugs.python.org/issue?@action=redirect&bpo=30185]: Avoid KeyboardInterrupt tracebacks in forkserver helper process when Ctrl-C is received.

bpo-30103 [https://bugs.python.org/issue?@action=redirect&bpo=30103]: binascii.b2a_uu() and uu.encode() now support using '`' as zero instead of space.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: add typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes. Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

bpo-30205 [https://bugs.python.org/issue?@action=redirect&bpo=30205]: Fix getsockname() for unbound AF_UNIX sockets on Linux.

bpo-30228 [https://bugs.python.org/issue?@action=redirect&bpo=30228]: The seek() and tell() methods of io.FileIO now set the internal seekable attribute to avoid one syscall on open() (in buffered or text mode).

bpo-30190 [https://bugs.python.org/issue?@action=redirect&bpo=30190]: unittest’s assertAlmostEqual and assertNotAlmostEqual provide a better message in case of failure which includes the difference between left and right arguments. (patch by Giampaolo Rodola’)

bpo-30101 [https://bugs.python.org/issue?@action=redirect&bpo=30101]: Add support for curses.A_ITALIC.

bpo-29822 [https://bugs.python.org/issue?@action=redirect&bpo=29822]: inspect.isabstract() now works during __init_subclass__. Patch by Nate Soares.

bpo-29960 [https://bugs.python.org/issue?@action=redirect&bpo=29960]: Preserve generator state when _random.Random.setstate() raises an exception. Patch by Bryan Olson.

bpo-30070 [https://bugs.python.org/issue?@action=redirect&bpo=30070]: Fixed leaks and crashes in errors handling in the parser module.

bpo-22352 [https://bugs.python.org/issue?@action=redirect&bpo=22352]: Column widths in the output of dis.dis() are now adjusted for large line numbers and instruction offsets.

bpo-30061 [https://bugs.python.org/issue?@action=redirect&bpo=30061]: Fixed crashes in IOBase methods __next__() and readlines() when readline() or __next__() respectively return non-sizeable object. Fixed possible other errors caused by not checking results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

bpo-30218 [https://bugs.python.org/issue?@action=redirect&bpo=30218]: Fix PathLike support for shutil.unpack_archive. Patch by Jelle Zijlstra.

bpo-10076 [https://bugs.python.org/issue?@action=redirect&bpo=10076]: Compiled regular expression and match objects in the re module now support copy.copy() and copy.deepcopy() (they are considered atomic).

bpo-30068 [https://bugs.python.org/issue?@action=redirect&bpo=30068]: _io._IOBase.readlines will check if it’s closed first when hint is present.

bpo-29694 [https://bugs.python.org/issue?@action=redirect&bpo=29694]: Fixed race condition in pathlib mkdir with flags parents=True. Patch by Armin Rigo.

bpo-29692 [https://bugs.python.org/issue?@action=redirect&bpo=29692]: Fixed arbitrary unchaining of RuntimeError exceptions in contextlib.contextmanager. Patch by Siddharth Velankar.

bpo-26187 [https://bugs.python.org/issue?@action=redirect&bpo=26187]: Test that sqlite3 trace callback is not called multiple times when schema is changing. Indirectly fixed by switching to use sqlite3_prepare_v2() in bpo-9303 [https://bugs.python.org/issue?@action=redirect&bpo=9303]. Patch by Aviv Palivoda.

bpo-30017 [https://bugs.python.org/issue?@action=redirect&bpo=30017]: Allowed calling the close() method of the zip entry writer object multiple times. Writing to a closed writer now always produces a ValueError.

bpo-29998 [https://bugs.python.org/issue?@action=redirect&bpo=29998]: Pickling and copying ImportError now preserves name and path attributes.

bpo-29995 [https://bugs.python.org/issue?@action=redirect&bpo=29995]: re.escape() now escapes only regex special characters.

bpo-29962 [https://bugs.python.org/issue?@action=redirect&bpo=29962]: Add math.remainder operation, implementing remainder as specified in IEEE 754.

bpo-29649 [https://bugs.python.org/issue?@action=redirect&bpo=29649]: Improve struct.pack_into() exception messages for problems with the buffer size and offset. Patch by Andrew Nester.

bpo-29654 [https://bugs.python.org/issue?@action=redirect&bpo=29654]: Support If-Modified-Since HTTP header (browser cache). Patch by Pierre Quentel.

bpo-29931 [https://bugs.python.org/issue?@action=redirect&bpo=29931]: Fixed comparison check for ipaddress.ip_interface objects. Patch by Sanjay Sundaresan.

bpo-29953 [https://bugs.python.org/issue?@action=redirect&bpo=29953]: Fixed memory leaks in the replace() method of datetime and time objects when pass out of bound fold argument.

bpo-29942 [https://bugs.python.org/issue?@action=redirect&bpo=29942]: Fix a crash in itertools.chain.from_iterable when encountering long runs of empty iterables.

bpo-10030 [https://bugs.python.org/issue?@action=redirect&bpo=10030]: Sped up reading encrypted ZIP files by 2 times.

bpo-29204 [https://bugs.python.org/issue?@action=redirect&bpo=29204]: Element.getiterator() and the html parameter of XMLParser() were deprecated only in the documentation (since Python 3.2 and 3.4 correspondingly). Now using them emits a deprecation warning.

bpo-27863 [https://bugs.python.org/issue?@action=redirect&bpo=27863]: Fixed multiple crashes in ElementTree caused by race conditions and wrong types.

bpo-25996 [https://bugs.python.org/issue?@action=redirect&bpo=25996]: Added support of file descriptors in os.scandir() on Unix. os.fwalk() is sped up by 2 times by using os.scandir().

bpo-28699 [https://bugs.python.org/issue?@action=redirect&bpo=28699]: Fixed a bug in pools in multiprocessing.pool that raising an exception at the very first of an iterable may swallow the exception or make the program hang. Patch by Davin Potts and Xiang Zhang.

bpo-23890 [https://bugs.python.org/issue?@action=redirect&bpo=23890]: unittest.TestCase.assertRaises() now manually breaks a reference cycle to not keep objects alive longer than expected.

bpo-29901 [https://bugs.python.org/issue?@action=redirect&bpo=29901]: The zipapp module now supports general path-like objects, not just pathlib.Path.

bpo-25803 [https://bugs.python.org/issue?@action=redirect&bpo=25803]: Avoid incorrect errors raised by Path.mkdir(exist_ok=True) when the OS gives priority to errors such as EACCES over EEXIST.

bpo-29861 [https://bugs.python.org/issue?@action=redirect&bpo=29861]: Release references to tasks, their arguments and their results as soon as they are finished in multiprocessing.Pool.

bpo-19930 [https://bugs.python.org/issue?@action=redirect&bpo=19930]: The mode argument of os.makedirs() no longer affects the file permission bits of newly created intermediate-level directories.

bpo-29884 [https://bugs.python.org/issue?@action=redirect&bpo=29884]: faulthandler: Restore the old sigaltstack during teardown. Patch by Christophe Zeitouny.

bpo-25455 [https://bugs.python.org/issue?@action=redirect&bpo=25455]: Fixed crashes in repr of recursive buffered file-like objects.

bpo-29800 [https://bugs.python.org/issue?@action=redirect&bpo=29800]: Fix crashes in partial.__repr__ if the keys of partial.keywords are not strings. Patch by Michael Seifert.

bpo-8256 [https://bugs.python.org/issue?@action=redirect&bpo=8256]: Fixed possible failing or crashing input() if attributes “encoding” or “errors” of sys.stdin or sys.stdout are not set or are not strings.

bpo-28692 [https://bugs.python.org/issue?@action=redirect&bpo=28692]: Using non-integer value for selecting a plural form in gettext is now deprecated.

bpo-26121 [https://bugs.python.org/issue?@action=redirect&bpo=26121]: Use C library implementation for math functions erf() and erfc().

bpo-29619 [https://bugs.python.org/issue?@action=redirect&bpo=29619]: os.stat() and os.DirEntry.inode() now convert inode (st_ino) using unsigned integers.

bpo-28298 [https://bugs.python.org/issue?@action=redirect&bpo=28298]: Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from accepting big intables (objects that have __int__) as elements.

bpo-29645 [https://bugs.python.org/issue?@action=redirect&bpo=29645]: Speed up importing the webbrowser module. webbrowser.register() is now thread-safe.

bpo-28231 [https://bugs.python.org/issue?@action=redirect&bpo=28231]: The zipfile module now accepts path-like objects for external paths.

bpo-26915 [https://bugs.python.org/issue?@action=redirect&bpo=26915]: index() and count() methods of collections.abc.Sequence now check identity before checking equality when do comparisons.

bpo-28682 [https://bugs.python.org/issue?@action=redirect&bpo=28682]: Added support for bytes paths in os.fwalk().

bpo-29728 [https://bugs.python.org/issue?@action=redirect&bpo=29728]: Add new socket.TCP_NOTSENT_LOWAT (Linux 3.12) constant. Patch by Nathaniel J. Smith.

bpo-29623 [https://bugs.python.org/issue?@action=redirect&bpo=29623]: Allow use of path-like object as a single argument in ConfigParser.read(). Patch by David Ellis.

bpo-9303 [https://bugs.python.org/issue?@action=redirect&bpo=9303]: Migrate sqlite3 module to _v2 API. Patch by Aviv Palivoda.

bpo-28963 [https://bugs.python.org/issue?@action=redirect&bpo=28963]: Fix out of bound iteration in asyncio.Future.remove_done_callback implemented in C.

bpo-29704 [https://bugs.python.org/issue?@action=redirect&bpo=29704]: asyncio.subprocess.SubprocessStreamProtocol no longer closes before all pipes are closed.

bpo-29271 [https://bugs.python.org/issue?@action=redirect&bpo=29271]: Fix Task.current_task and Task.all_tasks implemented in C to accept None argument as their pure Python implementation.

bpo-29703 [https://bugs.python.org/issue?@action=redirect&bpo=29703]: Fix asyncio to support instantiation of new event loops in child processes.

bpo-29615 [https://bugs.python.org/issue?@action=redirect&bpo=29615]: SimpleXMLRPCDispatcher no longer chains KeyError (or any other exception) to exception(s) raised in the dispatched methods. Patch by Petr Motejlek.

bpo-7769 [https://bugs.python.org/issue?@action=redirect&bpo=7769]: Method register_function() of xmlrpc.server.SimpleXMLRPCDispatcher and its subclasses can now be used as a decorator.

bpo-29376 [https://bugs.python.org/issue?@action=redirect&bpo=29376]: Fix assertion error in threading._DummyThread.is_alive().

bpo-28624 [https://bugs.python.org/issue?@action=redirect&bpo=28624]: Add a test that checks that cwd parameter of Popen() accepts PathLike objects. Patch by Sayan Chowdhury.

bpo-28518 [https://bugs.python.org/issue?@action=redirect&bpo=28518]: Start a transaction implicitly before a DML statement. Patch by Aviv Palivoda.

bpo-29742 [https://bugs.python.org/issue?@action=redirect&bpo=29742]: get_extra_info() raises exception if get called on closed ssl transport. Patch by Nikolay Kim.

bpo-16285 [https://bugs.python.org/issue?@action=redirect&bpo=16285]: urllib.parse.quote is now based on RFC 3986 and hence includes ‘~’ in the set of characters that is not quoted by default. Patch by Christian Theune and Ratnadeep Debnath.

bpo-29532 [https://bugs.python.org/issue?@action=redirect&bpo=29532]: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation.

bpo-29110 [https://bugs.python.org/issue?@action=redirect&bpo=29110]: Fix file object leak in aifc.open() when file is given as a filesystem path and is not in valid AIFF format. Patch by Anthony Zhang.

bpo-22807 [https://bugs.python.org/issue?@action=redirect&bpo=22807]: Add uuid.SafeUUID and uuid.UUID.is_safe to relay information from the platform about whether generated UUIDs are generated with a multiprocessing safe method.

bpo-29576 [https://bugs.python.org/issue?@action=redirect&bpo=29576]: Improve some deprecations in importlib. Some deprecated methods now emit DeprecationWarnings and have better descriptive messages.

bpo-29534 [https://bugs.python.org/issue?@action=redirect&bpo=29534]: Fixed different behaviour of Decimal.from_float() for _decimal and _pydecimal. Thanks Andrew Nester.

bpo-10379 [https://bugs.python.org/issue?@action=redirect&bpo=10379]: locale.format_string now supports the ‘monetary’ keyword argument, and locale.format is deprecated.

bpo-29851 [https://bugs.python.org/issue?@action=redirect&bpo=29851]: importlib.reload() now raises ModuleNotFoundError if the module lacks a spec.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: typing.Counter, typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

bpo-29100 [https://bugs.python.org/issue?@action=redirect&bpo=29100]: Fix datetime.fromtimestamp() regression introduced in Python 3.6.0: check minimum and maximum years.

bpo-29416 [https://bugs.python.org/issue?@action=redirect&bpo=29416]: Prevent infinite loop in pathlib.Path.mkdir

bpo-29444 [https://bugs.python.org/issue?@action=redirect&bpo=29444]: Fixed out-of-bounds buffer access in the group() method of the match object. Based on patch by WGH.

bpo-29377 [https://bugs.python.org/issue?@action=redirect&bpo=29377]: Add WrapperDescriptorType, MethodWrapperType, and MethodDescriptorType built-in types to types module. Original patch by Manuel Krebber.

bpo-29218 [https://bugs.python.org/issue?@action=redirect&bpo=29218]: Unused install_misc command is now removed. It has been documented as unused since 2000. Patch by Eric N. Vander Weele.

bpo-29368 [https://bugs.python.org/issue?@action=redirect&bpo=29368]: The extend() method is now called instead of the append() method when unpickle collections.deque and other list-like objects. This can speed up unpickling to 2 times.

bpo-29338 [https://bugs.python.org/issue?@action=redirect&bpo=29338]: The help of a builtin or extension class now includes the constructor signature if __text_signature__ is provided for the class.

bpo-29335 [https://bugs.python.org/issue?@action=redirect&bpo=29335]: Fix subprocess.Popen.wait() when the child process has exited to a stopped instead of terminated state (ex: when under ptrace).

bpo-29290 [https://bugs.python.org/issue?@action=redirect&bpo=29290]: Fix a regression in argparse that help messages would wrap at non-breaking spaces.

bpo-28735 [https://bugs.python.org/issue?@action=redirect&bpo=28735]: Fixed the comparison of mock.MagickMock with mock.ANY.

bpo-29197 [https://bugs.python.org/issue?@action=redirect&bpo=29197]: Removed deprecated function ntpath.splitunc().

bpo-29210 [https://bugs.python.org/issue?@action=redirect&bpo=29210]: Removed support of deprecated argument “exclude” in tarfile.TarFile.add().

bpo-29219 [https://bugs.python.org/issue?@action=redirect&bpo=29219]: Fixed infinite recursion in the repr of uninitialized ctypes.CDLL instances.

bpo-29192 [https://bugs.python.org/issue?@action=redirect&bpo=29192]: Removed deprecated features in the http.cookies module.

bpo-29193 [https://bugs.python.org/issue?@action=redirect&bpo=29193]: A format string argument for string.Formatter.format() is now positional-only.

bpo-29195 [https://bugs.python.org/issue?@action=redirect&bpo=29195]: Removed support of deprecated undocumented keyword arguments in methods of regular expression objects.

bpo-28969 [https://bugs.python.org/issue?@action=redirect&bpo=28969]: Fixed race condition in C implementation of functools.lru_cache. KeyError could be raised when cached function with full cache was simultaneously called from different threads with the same uncached arguments.

bpo-20804 [https://bugs.python.org/issue?@action=redirect&bpo=20804]: The unittest.mock.sentinel attributes now preserve their identity when they are copied or pickled.

bpo-29142 [https://bugs.python.org/issue?@action=redirect&bpo=29142]: In urllib.request, suffixes in no_proxy environment variable with leading dots could match related hostnames again (e.g. .b.c matches a.b.c). Patch by Milan Oberkirch.

bpo-28961 [https://bugs.python.org/issue?@action=redirect&bpo=28961]: Fix unittest.mock._Call helper: don’t ignore the name parameter anymore. Patch written by Jiajun Huang.

bpo-15812 [https://bugs.python.org/issue?@action=redirect&bpo=15812]: inspect.getframeinfo() now correctly shows the first line of a context. Patch by Sam Breese.

bpo-28985 [https://bugs.python.org/issue?@action=redirect&bpo=28985]: Update authorizer constants in sqlite3 module. Patch by Dingyuan Wang.

bpo-29079 [https://bugs.python.org/issue?@action=redirect&bpo=29079]: Prevent infinite loop in pathlib.resolve() on Windows

bpo-13051 [https://bugs.python.org/issue?@action=redirect&bpo=13051]: Fixed recursion errors in large or resized curses.textpad.Textbox. Based on patch by Tycho Andersen.

bpo-9770 [https://bugs.python.org/issue?@action=redirect&bpo=9770]: curses.ascii predicates now work correctly with negative integers.

bpo-28427 [https://bugs.python.org/issue?@action=redirect&bpo=28427]: old keys should not remove new values from WeakValueDictionary when collecting from another thread.

bpo-28923 [https://bugs.python.org/issue?@action=redirect&bpo=28923]: Remove editor artifacts from Tix.py.

bpo-28871 [https://bugs.python.org/issue?@action=redirect&bpo=28871]: Fixed a crash when deallocate deep ElementTree.

bpo-19542 [https://bugs.python.org/issue?@action=redirect&bpo=19542]: Fix bugs in WeakValueDictionary.setdefault() and WeakValueDictionary.pop() when a GC collection happens in another thread.

bpo-20191 [https://bugs.python.org/issue?@action=redirect&bpo=20191]: Fixed a crash in resource.prlimit() when passing a sequence that doesn’t own its elements as limits.

bpo-16255 [https://bugs.python.org/issue?@action=redirect&bpo=16255]: subprocess.Popen uses /system/bin/sh on Android as the shell, instead of /bin/sh.

bpo-28779 [https://bugs.python.org/issue?@action=redirect&bpo=28779]: multiprocessing.set_forkserver_preload() would crash the forkserver process if a preloaded module instantiated some multiprocessing objects such as locks.

bpo-26937 [https://bugs.python.org/issue?@action=redirect&bpo=26937]: The chown() method of the tarfile.TarFile class does not fail now when the grp module cannot be imported, as for example on Android platforms.

bpo-28847 [https://bugs.python.org/issue?@action=redirect&bpo=28847]: dbm.dumb now supports reading read-only files and no longer writes the index file when it is not changed. A deprecation warning is now emitted if the index file is missed and recreated in the ‘r’ and ‘w’ modes (will be an error in future Python releases).

bpo-27030 [https://bugs.python.org/issue?@action=redirect&bpo=27030]: Unknown escapes consisting of '\' and an ASCII letter in re.sub() replacement templates regular expressions now are errors.

bpo-28835 [https://bugs.python.org/issue?@action=redirect&bpo=28835]: Fix a regression introduced in warnings.catch_warnings(): call warnings.showwarning() if it was overridden inside the context manager.

bpo-27172 [https://bugs.python.org/issue?@action=redirect&bpo=27172]: To assist with upgrades from 2.7, the previously documented deprecation of inspect.getfullargspec() has been reversed. This decision may be revisited again after the Python 2.7 branch is no longer officially supported.

bpo-28740 [https://bugs.python.org/issue?@action=redirect&bpo=28740]: Add sys.getandroidapilevel(): return the build time API version of Android as an integer. Function only available on Android.

bpo-26273 [https://bugs.python.org/issue?@action=redirect&bpo=26273]: Add new socket.TCP_CONGESTION (Linux 2.6.13) and socket.TCP_USER_TIMEOUT (Linux 2.6.37) constants. Patch written by Omar Sandoval.

bpo-28752 [https://bugs.python.org/issue?@action=redirect&bpo=28752]: Restored the __reduce__() methods of datetime objects.

bpo-28727 [https://bugs.python.org/issue?@action=redirect&bpo=28727]: Regular expression patterns, _sre.SRE_Pattern objects created by re.compile(), become comparable (only x==y and x!=y operators). This change should fix the bpo-18383 [https://bugs.python.org/issue?@action=redirect&bpo=18383]: don’t duplicate warning filters when the warnings module is reloaded (thing usually only done in unit tests).

bpo-20572 [https://bugs.python.org/issue?@action=redirect&bpo=20572]: Remove the subprocess.Popen.wait endtime parameter. It was deprecated in 3.4 and undocumented prior to that.

bpo-25659 [https://bugs.python.org/issue?@action=redirect&bpo=25659]: In ctypes, prevent a crash calling the from_buffer() and from_buffer_copy() methods on abstract classes like Array.

bpo-28548 [https://bugs.python.org/issue?@action=redirect&bpo=28548]: In the “http.server” module, parse the protocol version if possible, to avoid using HTTP 0.9 in some error responses.

bpo-19717 [https://bugs.python.org/issue?@action=redirect&bpo=19717]: Makes Path.resolve() succeed on paths that do not exist. Patch by Vajrasky Kok

bpo-28563 [https://bugs.python.org/issue?@action=redirect&bpo=28563]: Fixed possible DoS and arbitrary code execution when handle plural form selections in the gettext module. The expression parser now supports exact syntax supported by GNU gettext.

bpo-28387 [https://bugs.python.org/issue?@action=redirect&bpo=28387]: Fixed possible crash in _io.TextIOWrapper deallocator when the garbage collector is invoked in other thread. Based on patch by Sebastian Cufre.

bpo-27517 [https://bugs.python.org/issue?@action=redirect&bpo=27517]: LZMA compressor and decompressor no longer raise exceptions if given empty data twice. Patch by Benjamin Fogle.

bpo-28549 [https://bugs.python.org/issue?@action=redirect&bpo=28549]: Fixed segfault in curses’s addch() with ncurses6.

bpo-28449 [https://bugs.python.org/issue?@action=redirect&bpo=28449]: tarfile.open() with mode “r” or “r:” now tries to open a tar file with compression before trying to open it without compression. Otherwise it had 50% chance failed with ignore_zeros=True.

bpo-23262 [https://bugs.python.org/issue?@action=redirect&bpo=23262]: The webbrowser module now supports Firefox 36+ and derived browsers. Based on patch by Oleg Broytman.

bpo-24241 [https://bugs.python.org/issue?@action=redirect&bpo=24241]: The webbrowser in an X environment now prefers using the default browser directly. Also, the webbrowser register() function now has a documented ‘preferred’ argument, to specify browsers to be returned by get() with no arguments. Patch by David Steele

bpo-27939 [https://bugs.python.org/issue?@action=redirect&bpo=27939]: Fixed bugs in tkinter.ttk.LabeledScale and tkinter.Scale caused by representing the scale as float value internally in Tk. tkinter.IntVar now works if float value is set to underlying Tk variable.

bpo-28255 [https://bugs.python.org/issue?@action=redirect&bpo=28255]: calendar.TextCalendar.prweek() no longer prints a space after a weeks’s calendar. calendar.TextCalendar.pryear() no longer prints redundant newline after a year’s calendar. Based on patch by Xiang Zhang.

bpo-28255 [https://bugs.python.org/issue?@action=redirect&bpo=28255]: calendar.TextCalendar.prmonth() no longer prints a space at the start of new line after printing a month’s calendar. Patch by Xiang Zhang.

bpo-20491 [https://bugs.python.org/issue?@action=redirect&bpo=20491]: The textwrap.TextWrapper class now honors non-breaking spaces. Based on patch by Kaarle Ritvanen.

bpo-28353 [https://bugs.python.org/issue?@action=redirect&bpo=28353]: os.fwalk() no longer fails on broken links.

bpo-28430 [https://bugs.python.org/issue?@action=redirect&bpo=28430]: Fix iterator of C implemented asyncio.Future doesn’t accept non-None value is passed to it.send(val).

bpo-27025 [https://bugs.python.org/issue?@action=redirect&bpo=27025]: Generated names for Tkinter widgets now start by the “!” prefix for readability.

bpo-25464 [https://bugs.python.org/issue?@action=redirect&bpo=25464]: Fixed HList.header_exists() in tkinter.tix module by addin a workaround to Tix library bug.

bpo-28488 [https://bugs.python.org/issue?@action=redirect&bpo=28488]: shutil.make_archive() no longer adds entry “./” to ZIP archive.

bpo-25953 [https://bugs.python.org/issue?@action=redirect&bpo=25953]: re.sub() now raises an error for invalid numerical group reference in replacement template even if the pattern is not found in the string. Error message for invalid group reference now includes the group index and the position of the reference. Based on patch by SilentGhost.

bpo-28469 [https://bugs.python.org/issue?@action=redirect&bpo=28469]: timeit now uses the sequence 1, 2, 5, 10, 20, 50,… instead of 1, 10, 100,… for autoranging.

bpo-28115 [https://bugs.python.org/issue?@action=redirect&bpo=28115]: Command-line interface of the zipfile module now uses argparse. Added support of long options.

bpo-18219 [https://bugs.python.org/issue?@action=redirect&bpo=18219]: Optimize csv.DictWriter for large number of columns. Patch by Mariatta Wijaya.

bpo-28448 [https://bugs.python.org/issue?@action=redirect&bpo=28448]: Fix C implemented asyncio.Future didn’t work on Windows.

bpo-23214 [https://bugs.python.org/issue?@action=redirect&bpo=23214]: In the “io” module, the argument to BufferedReader and BytesIO’s read1() methods is now optional and can be -1, matching the BufferedIOBase specification.

bpo-28480 [https://bugs.python.org/issue?@action=redirect&bpo=28480]: Fix error building socket module when multithreading is disabled.

bpo-28240 [https://bugs.python.org/issue?@action=redirect&bpo=28240]: timeit: remove -c/--clock and -t/--time command line options which were deprecated since Python 3.3.

bpo-28240 [https://bugs.python.org/issue?@action=redirect&bpo=28240]: timeit now repeats the benchmarks 5 times instead of only 3 to make benchmarks more reliable.

bpo-28240 [https://bugs.python.org/issue?@action=redirect&bpo=28240]: timeit autorange now uses a single loop iteration if the benchmark takes less than 10 seconds, instead of 10 iterations. “python3 -m timeit -s ‘import time’ ‘time.sleep(1)’” now takes 4 seconds instead of 40 seconds.

Distutils.sdist now looks for README and setup.py files with case sensitivity. This behavior matches that found in Setuptools 6.0 and later. See setuptools 100 [https://github.com/pypa/setuptools/issues/100] for rationale.

bpo-24452 [https://bugs.python.org/issue?@action=redirect&bpo=24452]: Make webbrowser support Chrome on Mac OS X. Patch by Ned Batchelder.

bpo-20766 [https://bugs.python.org/issue?@action=redirect&bpo=20766]: Fix references leaked by pdb in the handling of SIGINT handlers.

bpo-27998 [https://bugs.python.org/issue?@action=redirect&bpo=27998]: Fixed bytes path support in os.scandir() on Windows. Patch by Eryk Sun.

bpo-28317 [https://bugs.python.org/issue?@action=redirect&bpo=28317]: The disassembler now decodes FORMAT_VALUE argument.

bpo-28380 [https://bugs.python.org/issue?@action=redirect&bpo=28380]: unittest.mock Mock autospec functions now properly support assert_called, assert_not_called, and assert_called_once.

bpo-28229 [https://bugs.python.org/issue?@action=redirect&bpo=28229]: lzma module now supports pathlib.

bpo-28321 [https://bugs.python.org/issue?@action=redirect&bpo=28321]: Fixed writing non-BMP characters with binary format in plistlib.

bpo-28225 [https://bugs.python.org/issue?@action=redirect&bpo=28225]: bz2 module now supports pathlib. Initial patch by Ethan Furman.

bpo-28227 [https://bugs.python.org/issue?@action=redirect&bpo=28227]: gzip now supports pathlib. Patch by Ethan Furman.

bpo-28332 [https://bugs.python.org/issue?@action=redirect&bpo=28332]: Deprecated silent truncations in socket.htons and socket.ntohs. Original patch by Oren Milman.

bpo-27358 [https://bugs.python.org/issue?@action=redirect&bpo=27358]: Optimized merging var-keyword arguments and improved error message when passing a non-mapping as a var-keyword argument.

bpo-28257 [https://bugs.python.org/issue?@action=redirect&bpo=28257]: Improved error message when passing a non-iterable as a var-positional argument. Added opcode BUILD_TUPLE_UNPACK_WITH_CALL.

bpo-28322 [https://bugs.python.org/issue?@action=redirect&bpo=28322]: Fixed possible crashes when unpickle itertools objects from incorrect pickle data. Based on patch by John Leitch.

bpo-28228 [https://bugs.python.org/issue?@action=redirect&bpo=28228]: imghdr now supports pathlib.

bpo-28226 [https://bugs.python.org/issue?@action=redirect&bpo=28226]: compileall now supports pathlib.

bpo-28314 [https://bugs.python.org/issue?@action=redirect&bpo=28314]: Fix function declaration (C flags) for the getiterator() method of xml.etree.ElementTree.Element.

bpo-28148 [https://bugs.python.org/issue?@action=redirect&bpo=28148]: Stop using localtime() and gmtime() in the time module. Introduced platform independent _PyTime_localtime API that is similar to POSIX localtime_r, but available on all platforms. Patch by Ed Schouten.

bpo-28253 [https://bugs.python.org/issue?@action=redirect&bpo=28253]: Fixed calendar functions for extreme months: 0001-01 and 9999-12. Methods itermonthdays() and itermonthdays2() are reimplemented so that they don’t call itermonthdates() which can cause datetime.date under/overflow.

bpo-28275 [https://bugs.python.org/issue?@action=redirect&bpo=28275]: Fixed possible use after free in the decompress() methods of the LZMADecompressor and BZ2Decompressor classes. Original patch by John Leitch.

bpo-27897 [https://bugs.python.org/issue?@action=redirect&bpo=27897]: Fixed possible crash in sqlite3.Connection.create_collation() if pass invalid string-like object as a name. Patch by Xiang Zhang.

bpo-18844 [https://bugs.python.org/issue?@action=redirect&bpo=18844]: random.choices() now has k as a keyword-only argument to improve the readability of common cases and come into line with the signature used in other languages.

bpo-18893 [https://bugs.python.org/issue?@action=redirect&bpo=18893]: Fix invalid exception handling in Lib/ctypes/macholib/dyld.py. Patch by Madison May.

bpo-27611 [https://bugs.python.org/issue?@action=redirect&bpo=27611]: Fixed support of default root window in the tkinter.tix module. Added the master parameter in the DisplayStyle constructor.

bpo-27348 [https://bugs.python.org/issue?@action=redirect&bpo=27348]: In the traceback module, restore the formatting of exception messages like “Exception: None”. This fixes a regression introduced in 3.5a2.

bpo-25651 [https://bugs.python.org/issue?@action=redirect&bpo=25651]: Allow false values to be used for msg parameter of subTest().

bpo-27778 [https://bugs.python.org/issue?@action=redirect&bpo=27778]: Fix a memory leak in os.getrandom() when the getrandom() is interrupted by a signal and a signal handler raises a Python exception.

bpo-28200 [https://bugs.python.org/issue?@action=redirect&bpo=28200]: Fix memory leak on Windows in the os module (fix path_converter() function).

bpo-25400 [https://bugs.python.org/issue?@action=redirect&bpo=25400]: RobotFileParser now correctly returns default values for crawl_delay and request_rate. Initial patch by Peter Wirtz.

bpo-27932 [https://bugs.python.org/issue?@action=redirect&bpo=27932]: Prevent memory leak in win32_ver().

Fix UnboundLocalError in socket._sendfile_use_sendfile.

bpo-28075 [https://bugs.python.org/issue?@action=redirect&bpo=28075]: Check for ERROR_ACCESS_DENIED in Windows implementation of os.stat(). Patch by Eryk Sun.

bpo-22493 [https://bugs.python.org/issue?@action=redirect&bpo=22493]: Warning message emitted by using inline flags in the middle of regular expression now contains a (truncated) regex pattern. Patch by Tim Graham.

bpo-25270 [https://bugs.python.org/issue?@action=redirect&bpo=25270]: Prevent codecs.escape_encode() from raising SystemError when an empty bytestring is passed.

bpo-28181 [https://bugs.python.org/issue?@action=redirect&bpo=28181]: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

bpo-25895 [https://bugs.python.org/issue?@action=redirect&bpo=25895]: Enable WebSocket URL schemes in urllib.parse.urljoin. Patch by Gergely Imreh and Markus Holtermann.

bpo-28114 [https://bugs.python.org/issue?@action=redirect&bpo=28114]: Fix a crash in parse_envlist() when env contains byte strings. Patch by Eryk Sun.

bpo-27599 [https://bugs.python.org/issue?@action=redirect&bpo=27599]: Fixed buffer overrun in binascii.b2a_qp() and binascii.a2b_qp().

bpo-27906 [https://bugs.python.org/issue?@action=redirect&bpo=27906]: Fix socket accept exhaustion during high TCP traffic. Patch by Kevin Conway.

bpo-28174 [https://bugs.python.org/issue?@action=redirect&bpo=28174]: Handle when SO_REUSEPORT isn’t properly supported. Patch by Seth Michael Larson.

bpo-26654 [https://bugs.python.org/issue?@action=redirect&bpo=26654]: Inspect functools.partial in asyncio.Handle.__repr__. Patch by iceboy.

bpo-26909 [https://bugs.python.org/issue?@action=redirect&bpo=26909]: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

bpo-28176 [https://bugs.python.org/issue?@action=redirect&bpo=28176]: Fix callbacks race in asyncio.SelectorLoop.sock_connect.

bpo-27759 [https://bugs.python.org/issue?@action=redirect&bpo=27759]: Fix selectors incorrectly retain invalid file descriptors. Patch by Mark Williams.

bpo-28325 [https://bugs.python.org/issue?@action=redirect&bpo=28325]: Remove vestigial MacOS 9 macurl2path module and its tests.

bpo-28368 [https://bugs.python.org/issue?@action=redirect&bpo=28368]: Refuse monitoring processes if the child watcher has no loop attached. Patch by Vincent Michel.

bpo-28369 [https://bugs.python.org/issue?@action=redirect&bpo=28369]: Raise RuntimeError when transport’s FD is used with add_reader, add_writer, etc.

bpo-28370 [https://bugs.python.org/issue?@action=redirect&bpo=28370]: Speedup asyncio.StreamReader.readexactly. Patch by Коренберг Марк.

bpo-28371 [https://bugs.python.org/issue?@action=redirect&bpo=28371]: Deprecate passing asyncio.Handles to run_in_executor.

bpo-28372 [https://bugs.python.org/issue?@action=redirect&bpo=28372]: Fix asyncio to support formatting of non-python coroutines.

bpo-28399 [https://bugs.python.org/issue?@action=redirect&bpo=28399]: Remove UNIX socket from FS before binding. Patch by Коренберг Марк.

bpo-27972 [https://bugs.python.org/issue?@action=redirect&bpo=27972]: Prohibit Tasks to await on themselves.

bpo-24142 [https://bugs.python.org/issue?@action=redirect&bpo=24142]: Reading a corrupt config file left configparser in an invalid state. Original patch by Florian Höch.

bpo-29581 [https://bugs.python.org/issue?@action=redirect&bpo=29581]: ABCMeta.__new__ now accepts **kwargs, allowing abstract base classes to use keyword parameters in __init_subclass__. Patch by Nate Soares.

bpo-25532 [https://bugs.python.org/issue?@action=redirect&bpo=25532]: inspect.unwrap() will now only try to unwrap an object sys.getrecursionlimit() times, to protect against objects which create a new object on every attribute access.

bpo-30177 [https://bugs.python.org/issue?@action=redirect&bpo=30177]: path.resolve(strict=False) no longer cuts the path after the first element not present in the filesystem. Patch by Antoine Pietri.

Documentation

bpo-31294 [https://bugs.python.org/issue?@action=redirect&bpo=31294]: Fix incomplete code snippet in the ZeroMQSocketListener and ZeroMQSocketHandler examples and adapt them to Python 3.

bpo-21649 [https://bugs.python.org/issue?@action=redirect&bpo=21649]: Add RFC 7525 and Mozilla server side TLS links to SSL documentation.

bpo-31128 [https://bugs.python.org/issue?@action=redirect&bpo=31128]: Allow the pydoc server to bind to arbitrary hostnames.

bpo-30803 [https://bugs.python.org/issue?@action=redirect&bpo=30803]: Clarify doc on truth value testing. Original patch by Peter Thomassen.

bpo-30176 [https://bugs.python.org/issue?@action=redirect&bpo=30176]: Add missing attribute related constants in curses documentation.

bpo-30052 [https://bugs.python.org/issue?@action=redirect&bpo=30052]: the link targets for bytes() and bytearray() are now their respective type definitions, rather than the corresponding builtin function entries. Use bytes and bytearray to reference the latter. In order to ensure this and future cross-reference updates are applied automatically, the daily documentation builds now disable the default output caching features in Sphinx.

bpo-26985 [https://bugs.python.org/issue?@action=redirect&bpo=26985]: Add missing info of code object in inspect documentation.

bpo-19824 [https://bugs.python.org/issue?@action=redirect&bpo=19824]: Improve the documentation for, and links to, template strings by emphasizing their utility for internationalization, and by clarifying some usage constraints. (See also: bpo-20314 [https://bugs.python.org/issue?@action=redirect&bpo=20314], bpo-12518 [https://bugs.python.org/issue?@action=redirect&bpo=12518])

bpo-28929 [https://bugs.python.org/issue?@action=redirect&bpo=28929]: Link the documentation to its source file on GitHub.

bpo-25008 [https://bugs.python.org/issue?@action=redirect&bpo=25008]: Document smtpd.py as effectively deprecated and add a pointer to aiosmtpd, a third-party asyncio-based replacement.

bpo-26355 [https://bugs.python.org/issue?@action=redirect&bpo=26355]: Add canonical header link on each page to corresponding major version of the documentation. Patch by Matthias Bussonnier.

bpo-29349 [https://bugs.python.org/issue?@action=redirect&bpo=29349]: Fix Python 2 syntax in code for building the documentation.

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: The data model reference and the porting section in the 3.6 What’s New guide now cover the additional __classcell__ handling needed for custom metaclasses to fully support PEP 487 [https://peps.python.org/pep-0487/] and zero-argument super().

bpo-28513 [https://bugs.python.org/issue?@action=redirect&bpo=28513]: Documented command-line interface of zipfile.

Tests

bpo-29639 [https://bugs.python.org/issue?@action=redirect&bpo=29639]: test.support.HOST is now “localhost”, a new HOSTv4 constant has been added for your 127.0.0.1 needs, similar to the existing HOSTv6 constant.

bpo-31320 [https://bugs.python.org/issue?@action=redirect&bpo=31320]: Silence traceback in test_ssl

bpo-31346 [https://bugs.python.org/issue?@action=redirect&bpo=31346]: Prefer PROTOCOL_TLS_CLIENT and PROTOCOL_TLS_SERVER protocols for SSLContext.

bpo-25674 [https://bugs.python.org/issue?@action=redirect&bpo=25674]: Remove sha256.tbs-internet.com ssl test

bpo-30715 [https://bugs.python.org/issue?@action=redirect&bpo=30715]: Address ALPN callback changes for OpenSSL 1.1.0f. The latest version behaves like OpenSSL 1.0.2 and no longer aborts handshake.

bpo-30822 [https://bugs.python.org/issue?@action=redirect&bpo=30822]: regrtest: Exclude tzdata from regrtest –all. When running the test suite using –use=all / -u all, exclude tzdata since it makes test_datetime too slow (15-20 min on some buildbots) which then times out on some buildbots. Fix also regrtest command line parser to allow passing -u extralargefile to run test_zipfile64.

bpo-30695 [https://bugs.python.org/issue?@action=redirect&bpo=30695]: Add the set_nomemory(start, stop) and remove_mem_hooks() functions to the _testcapi module.

bpo-30357 [https://bugs.python.org/issue?@action=redirect&bpo=30357]: test_thread: setUp() now uses support.threading_setup() and support.threading_cleanup() to wait until threads complete to avoid random side effects on following tests. Initial patch written by Grzegorz Grzywacz.

bpo-30197 [https://bugs.python.org/issue?@action=redirect&bpo=30197]: Enhanced functions swap_attr() and swap_item() in the test.support module. They now work when delete replaced attribute or item inside the with statement. The old value of the attribute or item (or None if it doesn’t exist) now will be assigned to the target of the “as” clause, if there is one.

bpo-24932 [https://bugs.python.org/issue?@action=redirect&bpo=24932]: Use proper command line parsing in _testembed

bpo-28950 [https://bugs.python.org/issue?@action=redirect&bpo=28950]: Disallow -j0 to be combined with -T/-l in regrtest command line arguments.

bpo-28683 [https://bugs.python.org/issue?@action=redirect&bpo=28683]: Fix the tests that bind() a unix socket and raise PermissionError on Android for a non-root user.

bpo-26936 [https://bugs.python.org/issue?@action=redirect&bpo=26936]: Fix the test_socket failures on Android - getservbyname(), getservbyport() and getaddrinfo() are broken on some Android API levels.

bpo-28666 [https://bugs.python.org/issue?@action=redirect&bpo=28666]: Now test.support.rmtree is able to remove unwritable or unreadable directories.

bpo-23839 [https://bugs.python.org/issue?@action=redirect&bpo=23839]: Various caches now are cleared before running every test file.

bpo-26944 [https://bugs.python.org/issue?@action=redirect&bpo=26944]: Fix test_posix for Android where ‘id -G’ is entirely wrong or missing the effective gid.

bpo-28409 [https://bugs.python.org/issue?@action=redirect&bpo=28409]: regrtest: fix the parser of command line arguments.

bpo-28217 [https://bugs.python.org/issue?@action=redirect&bpo=28217]: Adds _testconsole module to test console input.

bpo-26939 [https://bugs.python.org/issue?@action=redirect&bpo=26939]: Add the support.setswitchinterval() function to fix test_functools hanging on the Android armv7 qemu emulator.

Build

bpo-31354 [https://bugs.python.org/issue?@action=redirect&bpo=31354]: Allow --with-lto to be used on all builds, not just make profile-opt.

bpo-31370 [https://bugs.python.org/issue?@action=redirect&bpo=31370]: Remove support for building –without-threads. This option is not really useful anymore in the 21st century. Removing lots of conditional paths allows us to simplify the code base, including in difficult to maintain low-level internal code.

bpo-31341 [https://bugs.python.org/issue?@action=redirect&bpo=31341]: Per PEP 11 [https://peps.python.org/pep-0011/], support for the IRIX operating system was removed.

bpo-30854 [https://bugs.python.org/issue?@action=redirect&bpo=30854]: Fix compile error when compiling –without-threads. Patch by Masayuki Yamamoto.

bpo-30687 [https://bugs.python.org/issue?@action=redirect&bpo=30687]: Locate msbuild.exe on Windows when building rather than vcvarsall.bat

bpo-20210 [https://bugs.python.org/issue?@action=redirect&bpo=20210]: Support the disabled marker in Setup files. Extension modules listed after this marker are not built at all, neither by the Makefile nor by setup.py.

bpo-29941 [https://bugs.python.org/issue?@action=redirect&bpo=29941]: Add --with-assertions configure flag to explicitly enable C assert() checks. Defaults to off. --with-pydebug implies --with-assertions.

bpo-28787 [https://bugs.python.org/issue?@action=redirect&bpo=28787]: Fix out-of-tree builds of Python when configured with --with--dtrace.

bpo-29243 [https://bugs.python.org/issue?@action=redirect&bpo=29243]: Prevent unnecessary rebuilding of Python during make test, make install and some other make targets when configured with --enable-optimizations.

bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404]: Don’t regenerate generated files based on file modification time anymore: the action is now explicit. Replace make touch with make regen-all.

bpo-29643 [https://bugs.python.org/issue?@action=redirect&bpo=29643]: Fix --enable-optimization didn’t work.

bpo-27593 [https://bugs.python.org/issue?@action=redirect&bpo=27593]: sys.version and the platform module python_build(), python_branch(), and python_revision() functions now use git information rather than hg when building from a repo.

bpo-29572 [https://bugs.python.org/issue?@action=redirect&bpo=29572]: Update Windows build and OS X installers to use OpenSSL 1.0.2k.

bpo-27659 [https://bugs.python.org/issue?@action=redirect&bpo=27659]: Prohibit implicit C function declarations: use -Werror=implicit-function-declaration when possible (GCC and Clang, but it depends on the compiler version). Patch written by Chi Hsuan Yen.

bpo-29384 [https://bugs.python.org/issue?@action=redirect&bpo=29384]: Remove old Be OS helper scripts.

bpo-26851 [https://bugs.python.org/issue?@action=redirect&bpo=26851]: Set Android compilation and link flags.

bpo-28768 [https://bugs.python.org/issue?@action=redirect&bpo=28768]: Fix implicit declaration of function _setmode. Patch by Masayuki Yamamoto

bpo-29080 [https://bugs.python.org/issue?@action=redirect&bpo=29080]: Removes hard dependency on hg.exe from PCBuild/build.bat

bpo-23903 [https://bugs.python.org/issue?@action=redirect&bpo=23903]: Added missed names to PC/python3.def.

bpo-28762 [https://bugs.python.org/issue?@action=redirect&bpo=28762]: lockf() is available on Android API level 24, but the F_LOCK macro is not defined in android-ndk-r13.

bpo-28538 [https://bugs.python.org/issue?@action=redirect&bpo=28538]: Fix the compilation error that occurs because if_nameindex() is available on Android API level 24, but the if_nameindex structure is not defined.

bpo-20211 [https://bugs.python.org/issue?@action=redirect&bpo=20211]: Do not add the directory for installing C header files and the directory for installing object code libraries to the cross compilation search paths. Original patch by Thomas Petazzoni.

bpo-28849 [https://bugs.python.org/issue?@action=redirect&bpo=28849]: Do not define sys.implementation._multiarch on Android.

bpo-10656 [https://bugs.python.org/issue?@action=redirect&bpo=10656]: Fix out-of-tree building on AIX. Patch by Tristan Carel and Michael Haubenwallner.

bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359]: Rename –with-optimiations to –enable-optimizations.

bpo-28444 [https://bugs.python.org/issue?@action=redirect&bpo=28444]: Fix missing extensions modules when cross compiling.

bpo-28208 [https://bugs.python.org/issue?@action=redirect&bpo=28208]: Update Windows build and OS X installers to use SQLite 3.14.2.

bpo-28248 [https://bugs.python.org/issue?@action=redirect&bpo=28248]: Update Windows build and OS X installers to use OpenSSL 1.0.2j.

bpo-21124 [https://bugs.python.org/issue?@action=redirect&bpo=21124]: Fix building the _struct module on Cygwin by passing NULL instead of &PyType_Type to PyVarObject_HEAD_INIT. Patch by Masayuki Yamamoto.

bpo-13756 [https://bugs.python.org/issue?@action=redirect&bpo=13756]: Fix building extensions modules on Cygwin. Patch by Roumen Petrov, based on original patch by Jason Tishler.

bpo-21085 [https://bugs.python.org/issue?@action=redirect&bpo=21085]: Add configure check for siginfo_t.si_band, which Cygwin does not provide. Patch by Masayuki Yamamoto with review and rebase by Erik Bray.

bpo-28258 [https://bugs.python.org/issue?@action=redirect&bpo=28258]: Fixed build with Estonian locale (python-config and distclean targets in Makefile). Patch by Arfrever Frehtes Taifersar Arahesis.

bpo-26661 [https://bugs.python.org/issue?@action=redirect&bpo=26661]: setup.py now detects system libffi with multiarch wrapper.

bpo-27979 [https://bugs.python.org/issue?@action=redirect&bpo=27979]: A full copy of libffi is no longer bundled for use when building _ctypes on non-OSX UNIX platforms. An installed copy of libffi is now required when building _ctypes on such platforms.

bpo-15819 [https://bugs.python.org/issue?@action=redirect&bpo=15819]: Remove redundant include search directory option for building outside the source tree.

bpo-28676 [https://bugs.python.org/issue?@action=redirect&bpo=28676]: Prevent missing ‘getentropy’ declaration warning on macOS. Patch by Gareth Rees.

Windows

bpo-31392 [https://bugs.python.org/issue?@action=redirect&bpo=31392]: Update Windows build to use OpenSSL 1.1.0f

bpo-30389 [https://bugs.python.org/issue?@action=redirect&bpo=30389]: Adds detection of Visual Studio 2017 to distutils on Windows.

bpo-31358 [https://bugs.python.org/issue?@action=redirect&bpo=31358]: zlib is no longer bundled in the CPython source, instead it is downloaded on demand just like bz2, lzma, OpenSSL, Tcl/Tk, and SQLite.

bpo-31340 [https://bugs.python.org/issue?@action=redirect&bpo=31340]: Change to building with MSVC v141 (included with Visual Studio 2017)

bpo-30581 [https://bugs.python.org/issue?@action=redirect&bpo=30581]: os.cpu_count() now returns the correct number of processors on Windows when the number of logical processors is greater than 64.

bpo-30916 [https://bugs.python.org/issue?@action=redirect&bpo=30916]: Pre-build OpenSSL, Tcl and Tk and include the binaries in the build.

bpo-30731 [https://bugs.python.org/issue?@action=redirect&bpo=30731]: Add a missing xmlns to python.manifest so that it matches the schema.

bpo-30291 [https://bugs.python.org/issue?@action=redirect&bpo=30291]: Allow requiring 64-bit interpreters from py.exe using -64 suffix. Contributed by Steve (Gadget) Barnes.

bpo-30362 [https://bugs.python.org/issue?@action=redirect&bpo=30362]: Adds list options (-0, -0p) to py.exe launcher. Contributed by Steve Barnes.

bpo-23451 [https://bugs.python.org/issue?@action=redirect&bpo=23451]: Fix socket deprecation warnings in socketmodule.c. Patch by Segev Finer.

bpo-30450 [https://bugs.python.org/issue?@action=redirect&bpo=30450]: The build process on Windows no longer depends on Subversion, instead pulling external code from GitHub via a Python script. If Python 3.6 is not found on the system (via py -3.6), NuGet is used to download a copy of 32-bit Python.

bpo-29579 [https://bugs.python.org/issue?@action=redirect&bpo=29579]: Removes readme.txt from the installer.

bpo-25778 [https://bugs.python.org/issue?@action=redirect&bpo=25778]: winreg does not truncate string correctly (Patch by Eryk Sun)

bpo-28896 [https://bugs.python.org/issue?@action=redirect&bpo=28896]: Deprecate WindowsRegistryFinder and disable it by default

bpo-28522 [https://bugs.python.org/issue?@action=redirect&bpo=28522]: Fixes mishandled buffer reallocation in getpathp.c

bpo-28402 [https://bugs.python.org/issue?@action=redirect&bpo=28402]: Adds signed catalog files for stdlib on Windows.

bpo-28333 [https://bugs.python.org/issue?@action=redirect&bpo=28333]: Enables Unicode for ps1/ps2 and input() prompts. (Patch by Eryk Sun)

bpo-28251 [https://bugs.python.org/issue?@action=redirect&bpo=28251]: Improvements to help manuals on Windows.

bpo-28110 [https://bugs.python.org/issue?@action=redirect&bpo=28110]: launcher.msi has different product codes between 32-bit and 64-bit

bpo-28161 [https://bugs.python.org/issue?@action=redirect&bpo=28161]: Opening CON for write access fails

bpo-28162 [https://bugs.python.org/issue?@action=redirect&bpo=28162]: WindowsConsoleIO readall() fails if first line starts with Ctrl+Z

bpo-28163 [https://bugs.python.org/issue?@action=redirect&bpo=28163]: WindowsConsoleIO fileno() passes wrong flags to _open_osfhandle

bpo-28164 [https://bugs.python.org/issue?@action=redirect&bpo=28164]: _PyIO_get_console_type fails for various paths

bpo-28137 [https://bugs.python.org/issue?@action=redirect&bpo=28137]: Renames Windows path file to ._pth

bpo-28138 [https://bugs.python.org/issue?@action=redirect&bpo=28138]: Windows ._pth file should allow import site

IDLE

bpo-31493 [https://bugs.python.org/issue?@action=redirect&bpo=31493]: IDLE code context – fix code update and font update timers. Canceling timers prevents a warning message when test_idle completes.

bpo-31488 [https://bugs.python.org/issue?@action=redirect&bpo=31488]: IDLE - Update non-key options in former extension classes. When applying configdialog changes, call .reload for each feature class. Change ParenMatch so updated options affect existing instances attached to existing editor windows.

bpo-31477 [https://bugs.python.org/issue?@action=redirect&bpo=31477]: IDLE - Improve rstrip entry in doc. Strip trailing whitespace strips more than blank spaces. Multiline string literals are not skipped.

bpo-31480 [https://bugs.python.org/issue?@action=redirect&bpo=31480]: IDLE - make tests pass with zzdummy extension disabled by default.

bpo-31421 [https://bugs.python.org/issue?@action=redirect&bpo=31421]: Document how IDLE runs tkinter programs. IDLE calls tcl/tk update in the background in order to make live interaction and experimentation with tkinter applications much easier.

bpo-31414 [https://bugs.python.org/issue?@action=redirect&bpo=31414]: IDLE – fix tk entry box tests by deleting first. Adding to an int entry is not the same as deleting and inserting because int(‘’) will fail.

bpo-31051 [https://bugs.python.org/issue?@action=redirect&bpo=31051]: Rearrange IDLE configdialog GenPage into Window, Editor, and Help sections.

bpo-30617 [https://bugs.python.org/issue?@action=redirect&bpo=30617]: IDLE - Add docstrings and tests for outwin subclass of editor. Move some data and functions from the class to module level. Patch by Cheryl Sabella.

bpo-31287 [https://bugs.python.org/issue?@action=redirect&bpo=31287]: IDLE - Do not modify tkinter.message in test_configdialog.

bpo-27099 [https://bugs.python.org/issue?@action=redirect&bpo=27099]: Convert IDLE’s built-in ‘extensions’ to regular features. About 10 IDLE features were implemented as supposedly optional extensions. Their different behavior could be confusing or worse for users and not good for maintenance. Hence the conversion. The main difference for users is that user configurable key bindings for builtin features are now handled uniformly. Now, editing a binding in a keyset only affects its value in the keyset. All bindings are defined together in the system-specific default keysets in config-extensions.def. All custom keysets are saved as a whole in config-extension.cfg. All take effect as soon as one clicks Apply or Ok. The affected events are ‘<<force-open-completions>>’, ‘<<expand-word>>’, ‘<<force-open-calltip>>’, ‘<<flash-paren>>’, ‘<<format-paragraph>>’, ‘<<run-module>>’, ‘<<check-module>>’, and ‘<<zoom-height>>’. Any (global) customizations made before 3.6.3 will not affect their keyset-specific customization after 3.6.3. and vice versa. Initial patch by Charles Wohlganger.

bpo-31206 [https://bugs.python.org/issue?@action=redirect&bpo=31206]: IDLE: Factor HighPage(Frame) class from ConfigDialog. Patch by Cheryl Sabella.

bpo-31001 [https://bugs.python.org/issue?@action=redirect&bpo=31001]: Add tests for configdialog highlight tab. Patch by Cheryl Sabella.

bpo-31205 [https://bugs.python.org/issue?@action=redirect&bpo=31205]: IDLE: Factor KeysPage(Frame) class from ConfigDialog. The slightly modified tests continue to pass. Patch by Cheryl Sabella.

bpo-31130 [https://bugs.python.org/issue?@action=redirect&bpo=31130]: IDLE – stop leaks in test_configdialog. Initial patch by Victor Stinner.

bpo-31002 [https://bugs.python.org/issue?@action=redirect&bpo=31002]: Add tests for configdialog keys tab. Patch by Cheryl Sabella.

bpo-19903 [https://bugs.python.org/issue?@action=redirect&bpo=19903]: IDLE: Calltips use inspect.signature instead of inspect.getfullargspec. This improves calltips for builtins converted to use Argument Clinic. Patch by Louie Lu.

bpo-31083 [https://bugs.python.org/issue?@action=redirect&bpo=31083]: IDLE - Add an outline of a TabPage class in configdialog. Update existing classes to match outline. Initial patch by Cheryl Sabella.

bpo-31050 [https://bugs.python.org/issue?@action=redirect&bpo=31050]: Factor GenPage(Frame) class from ConfigDialog. The slightly modified tests continue to pass. Patch by Cheryl Sabella.

bpo-31004 [https://bugs.python.org/issue?@action=redirect&bpo=31004]: IDLE - Factor FontPage(Frame) class from ConfigDialog. Slightly modified tests continue to pass. Fix General tests. Patch mostly by Cheryl Sabella.

bpo-30781 [https://bugs.python.org/issue?@action=redirect&bpo=30781]: IDLE - Use ttk widgets in ConfigDialog. Patches by Terry Jan Reedy and Cheryl Sabella.

bpo-31060 [https://bugs.python.org/issue?@action=redirect&bpo=31060]: IDLE - Finish rearranging methods of ConfigDialog Grouping methods pertaining to each tab and the buttons will aid writing tests and improving the tabs and will enable splitting the groups into classes.

bpo-30853 [https://bugs.python.org/issue?@action=redirect&bpo=30853]: IDLE – Factor a VarTrace class out of ConfigDialog. Instance tracers manages pairs consisting of a tk variable and a callback function. When tracing is turned on, setting the variable calls the function. Test coverage for the new class is 100%.

bpo-31003 [https://bugs.python.org/issue?@action=redirect&bpo=31003]: IDLE: Add more tests for General tab.

bpo-30993 [https://bugs.python.org/issue?@action=redirect&bpo=30993]: IDLE - Improve configdialog font page and tests. In configdialog: Document causal pathways in create_font_tab docstring. Simplify some attribute names. Move set_samples calls to var_changed_font (idea from Cheryl Sabella). Move related functions to positions after the create widgets function. In test_configdialog: Fix test_font_set so not order dependent. Fix renamed test_indent_scale so it tests the widget. Adjust tests for movement of set_samples call. Add tests for load functions. Put all font tests in one class and tab indent tests in another. Except for two lines, these tests completely cover the related functions.

bpo-30981 [https://bugs.python.org/issue?@action=redirect&bpo=30981]: IDLE – Add more configdialog font page tests.

bpo-28523 [https://bugs.python.org/issue?@action=redirect&bpo=28523]: IDLE: replace ‘colour’ with ‘color’ in configdialog.

bpo-30917 [https://bugs.python.org/issue?@action=redirect&bpo=30917]: Add tests for idlelib.config.IdleConf. Increase coverage from 46% to 96%. Patch by Louie Lu.

bpo-30934 [https://bugs.python.org/issue?@action=redirect&bpo=30934]: Document coverage details for idlelib tests. Add section to idlelib/idle-test/README.txt. Include check that branches are taken both ways. Exclude IDLE-specific code that does not run during unit tests.

bpo-30913 [https://bugs.python.org/issue?@action=redirect&bpo=30913]: IDLE: Document ConfigDialog tk Vars, methods, and widgets in docstrings This will facilitate improving the dialog and splitting up the class. Original patch by Cheryl Sabella.

bpo-30899 [https://bugs.python.org/issue?@action=redirect&bpo=30899]: IDLE: Add tests for ConfigParser subclasses in config. Patch by Louie Lu.

bpo-30881 [https://bugs.python.org/issue?@action=redirect&bpo=30881]: IDLE: Add docstrings to browser.py. Patch by Cheryl Sabella.

bpo-30851 [https://bugs.python.org/issue?@action=redirect&bpo=30851]: IDLE: Remove unused variables in configdialog. One is a duplicate, one is set but cannot be altered by users. Patch by Cheryl Sabella.

bpo-30870 [https://bugs.python.org/issue?@action=redirect&bpo=30870]: IDLE: In Settings dialog, select font with Up, Down keys as well as mouse. Initial patch by Louie Lu.

bpo-8231 [https://bugs.python.org/issue?@action=redirect&bpo=8231]: IDLE: call config.IdleConf.GetUserCfgDir only once.

bpo-30779 [https://bugs.python.org/issue?@action=redirect&bpo=30779]: IDLE: Factor ConfigChanges class from configdialog, put in config; test. * In config, put dump test code in a function; run it and unittest in ‘if __name__ == ‘__main__’. * Add class config.ConfigChanges based on changes_class_v4.py on bpo issue. * Add class test_config.ChangesTest, partly using configdialog_tests_v1.py. * Revise configdialog to use ConfigChanges; see tracker msg297804. * Revise test_configdialog to match configdialog changes. * Remove configdialog functions unused or moved to ConfigChanges. Cheryl Sabella contributed parts of the patch.

bpo-30777 [https://bugs.python.org/issue?@action=redirect&bpo=30777]: IDLE: configdialog - Add docstrings and fix comments. Patch by Cheryl Sabella.

bpo-30495 [https://bugs.python.org/issue?@action=redirect&bpo=30495]: IDLE: Improve textview with docstrings, PEP8 names, and more tests. Patch by Cheryl Sabella.

bpo-30723 [https://bugs.python.org/issue?@action=redirect&bpo=30723]: IDLE: Make several improvements to parenmatch. Add ‘parens’ style to highlight both opener and closer. Make ‘default’ style, which is not default, a synonym for ‘opener’. Make time-delay work the same with all styles. Add help for config dialog extensions tab, including help for parenmatch. Add new tests. Original patch by Charles Wohlganger.

bpo-30674 [https://bugs.python.org/issue?@action=redirect&bpo=30674]: IDLE: add docstrings to grep module. Patch by Cheryl Sabella

bpo-21519 [https://bugs.python.org/issue?@action=redirect&bpo=21519]: IDLE’s basic custom key entry dialog now detects duplicates properly. Original patch by Saimadhav Heblikar.

bpo-29910 [https://bugs.python.org/issue?@action=redirect&bpo=29910]: IDLE no longer deletes a character after commenting out a region by a key shortcut. Add return 'break' for this and other potential conflicts between IDLE and default key bindings.

bpo-30728 [https://bugs.python.org/issue?@action=redirect&bpo=30728]: Review and change idlelib.configdialog names. Lowercase method and attribute names. Replace ‘colour’ with ‘color’, expand overly cryptic names, delete unneeded underscores. Replace import * with specific imports. Patches by Cheryl Sabella.

bpo-6739 [https://bugs.python.org/issue?@action=redirect&bpo=6739]: IDLE: Verify user-entered key sequences by trying to bind them with tk. Add tests for all 3 validation functions. Original patch by G Polo. Tests added by Cheryl Sabella.

bpo-15786 [https://bugs.python.org/issue?@action=redirect&bpo=15786]: Fix several problems with IDLE’s autocompletion box. The following should now work: clicking on selection box items; using the scrollbar; selecting an item by hitting Return. Hangs on MacOSX should no longer happen. Patch by Louie Lu.

bpo-25514 [https://bugs.python.org/issue?@action=redirect&bpo=25514]: Add doc subsubsection about IDLE failure to start. Popup no-connection message directs users to this section.

bpo-30642 [https://bugs.python.org/issue?@action=redirect&bpo=30642]: Fix reference leaks in IDLE tests. Patches by Louie Lu and Terry Jan Reedy.

bpo-30495 [https://bugs.python.org/issue?@action=redirect&bpo=30495]: Add docstrings for textview.py and use PEP8 names. Patches by Cheryl Sabella and Terry Jan Reedy.

bpo-30290 [https://bugs.python.org/issue?@action=redirect&bpo=30290]: Help-about: use pep8 names and add tests. Increase coverage to 100%. Patches by Louie Lu, Cheryl Sabella, and Terry Jan Reedy.

bpo-30303 [https://bugs.python.org/issue?@action=redirect&bpo=30303]: Add _utest option to textview; add new tests. Increase coverage to 100%. Patches by Louie Lu and Terry Jan Reedy.

bpo-29071 [https://bugs.python.org/issue?@action=redirect&bpo=29071]: IDLE colors f-string prefixes (but not invalid ur prefixes).

bpo-28572 [https://bugs.python.org/issue?@action=redirect&bpo=28572]: Add 10% to coverage of IDLE’s test_configdialog. Update and augment description of the configuration system.

Tools/Demos

bpo-30983 [https://bugs.python.org/issue?@action=redirect&bpo=30983]: gdb integration commands (py-bt, etc.) work on optimized shared builds now, too. PEP 523 [https://peps.python.org/pep-0523/] introduced _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on non-debug shared builds. This broke the ability to use py-bt, py-up, and a few other Python-specific gdb integrations. The problem is fixed by only looking for _PyEval_EvalFrameDefault frames in python-gdb.py. Original patch by Bruno “Polaco” Penteado.

bpo-29748 [https://bugs.python.org/issue?@action=redirect&bpo=29748]: Added the slice index converter in Argument Clinic.

bpo-24037 [https://bugs.python.org/issue?@action=redirect&bpo=24037]: Argument Clinic now uses the converter bool(accept={int}) rather than int for semantical booleans. This avoids repeating the default value for Python and C and will help in converting to bool in future.

bpo-29367 [https://bugs.python.org/issue?@action=redirect&bpo=29367]: python-gdb.py now supports also method-wrapper (wrapperobject) objects.

bpo-28023 [https://bugs.python.org/issue?@action=redirect&bpo=28023]: Fix python-gdb.py didn’t support new dict implementation.

bpo-15369 [https://bugs.python.org/issue?@action=redirect&bpo=15369]: The pybench and pystone microbenchmark have been removed from Tools. Please use the new Python benchmark suite https://github.com/python/pyperformance which is more reliable and includes a portable version of pybench working on Python 2 and Python 3.

bpo-28102 [https://bugs.python.org/issue?@action=redirect&bpo=28102]: The zipfile module CLI now prints usage to stderr. Patch by Stephen J. Turnbull.

C API

bpo-31338 [https://bugs.python.org/issue?@action=redirect&bpo=31338]: Added the Py_UNREACHABLE() macro for code paths which are never expected to be reached. This and a few other useful macros are now documented in the C API manual.

bpo-30832 [https://bugs.python.org/issue?@action=redirect&bpo=30832]: Remove own implementation for thread-local storage. CPython has provided the own implementation for thread-local storage (TLS) on Python/thread.c, it’s used in the case which a platform has not supplied native TLS. However, currently all supported platforms (Windows and pthreads) have provided native TLS and defined the Py_HAVE_NATIVE_TLS macro with unconditional in any case.

bpo-30708 [https://bugs.python.org/issue?@action=redirect&bpo=30708]: PyUnicode_AsWideCharString() now raises a ValueError if the second argument is NULL and the wchar_t* string contains null characters.

bpo-16500 [https://bugs.python.org/issue?@action=redirect&bpo=16500]: Deprecate PyOS_AfterFork() and add PyOS_BeforeFork(), PyOS_AfterFork_Parent() and PyOS_AfterFork_Child().

bpo-6532 [https://bugs.python.org/issue?@action=redirect&bpo=6532]: The type of results of PyThread_start_new_thread() and PyThread_get_thread_ident(), and the id parameter of PyThreadState_SetAsyncExc() changed from “long” to “unsigned long”.

bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867]: Function PySlice_GetIndicesEx() is deprecated and replaced with a macro if Py_LIMITED_API is not set or set to the value between 0x03050400 and 0x03060000 (not including) or 0x03060100 or higher. Added functions PySlice_Unpack() and PySlice_AdjustIndices().

bpo-29083 [https://bugs.python.org/issue?@action=redirect&bpo=29083]: Fixed the declaration of some public API functions. PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and Py_BuildValue() were not available in limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

bpo-28769 [https://bugs.python.org/issue?@action=redirect&bpo=28769]: The result of PyUnicode_AsUTF8AndSize() and PyUnicode_AsUTF8() is now of type const char * rather of char *.

bpo-29058 [https://bugs.python.org/issue?@action=redirect&bpo=29058]: All stable API extensions added after Python 3.2 are now available only when Py_LIMITED_API is set to the PY_VERSION_HEX value of the minimum Python version supporting this API.

bpo-28822 [https://bugs.python.org/issue?@action=redirect&bpo=28822]: The index parameters start and end of PyUnicode_FindChar() are now adjusted to behave like str[start:end].

bpo-28808 [https://bugs.python.org/issue?@action=redirect&bpo=28808]: PyUnicode_CompareWithASCIIString() now never raises exceptions.

bpo-28761 [https://bugs.python.org/issue?@action=redirect&bpo=28761]: The fields name and doc of structures PyMemberDef, PyGetSetDef, PyStructSequence_Field, PyStructSequence_Desc, and wrapperbase are now of type const char * rather of char *.

bpo-28748 [https://bugs.python.org/issue?@action=redirect&bpo=28748]: Private variable _Py_PackageContext is now of type const char * rather of char *.

bpo-19569 [https://bugs.python.org/issue?@action=redirect&bpo=19569]: Compiler warnings are now emitted if use most of deprecated functions.

bpo-28426 [https://bugs.python.org/issue?@action=redirect&bpo=28426]: Deprecated undocumented functions PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(), PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().

Python 3.6.6 final

Release date: 2018-06-27

There were no new changes in version 3.6.6.

Python 3.6.6 release candidate 1

Release date: 2018-06-11

Core and Builtins

bpo-33786 [https://bugs.python.org/issue?@action=redirect&bpo=33786]: Fix asynchronous generators to handle GeneratorExit in athrow() correctly

bpo-30654 [https://bugs.python.org/issue?@action=redirect&bpo=30654]: Fixed reset of the SIGINT handler to SIG_DFL on interpreter shutdown even when there was a custom handler set previously. Patch by Philipp Kerling.

bpo-33622 [https://bugs.python.org/issue?@action=redirect&bpo=33622]: Fixed a leak when the garbage collector fails to add an object with the __del__ method or referenced by it into the gc.garbage list. PyGC_Collect() can now be called when an exception is set and preserves it.

bpo-31849 [https://bugs.python.org/issue?@action=redirect&bpo=31849]: Fix signed/unsigned comparison warning in pyhash.c.

bpo-33391 [https://bugs.python.org/issue?@action=redirect&bpo=33391]: Fix a leak in set_symmetric_difference().

bpo-28055 [https://bugs.python.org/issue?@action=redirect&bpo=28055]: Fix unaligned accesses in siphash24(). Patch by Rolf Eike Beer.

bpo-33231 [https://bugs.python.org/issue?@action=redirect&bpo=33231]: Fix potential memory leak in normalizestring().

bpo-29922 [https://bugs.python.org/issue?@action=redirect&bpo=29922]: Improved error messages in ‘async with’ when __aenter__() or __aexit__() return non-awaitable object.

bpo-33199 [https://bugs.python.org/issue?@action=redirect&bpo=33199]: Fix ma_version_tag in dict implementation is uninitialized when copying from key-sharing dict.

bpo-33041 [https://bugs.python.org/issue?@action=redirect&bpo=33041]: Fixed jumping when the function contains an async for loop.

bpo-32282 [https://bugs.python.org/issue?@action=redirect&bpo=32282]: Fix an unnecessary ifdef in the include of VersionHelpers.h in socketmodule on Windows.

bpo-21983 [https://bugs.python.org/issue?@action=redirect&bpo=21983]: Fix a crash in ctypes.cast() in case the type argument is a ctypes structured data type. Patch by Eryk Sun and Oren Milman.

Library

bpo-30167 [https://bugs.python.org/issue?@action=redirect&bpo=30167]: Prevent site.main() exception if PYTHONSTARTUP is set. Patch by Steve Weber.

bpo-33812 [https://bugs.python.org/issue?@action=redirect&bpo=33812]: Datetime instance d with non-None tzinfo, but with d.tzinfo.utcoffset(d) returning None is now treated as naive by the astimezone() method.

bpo-30805 [https://bugs.python.org/issue?@action=redirect&bpo=30805]: Avoid race condition with debug logging

bpo-33767 [https://bugs.python.org/issue?@action=redirect&bpo=33767]: The concatenation (+) and repetition (*) sequence operations now raise TypeError instead of SystemError when performed on mmap.mmap objects. Patch by Zackery Spytz.

bpo-32684 [https://bugs.python.org/issue?@action=redirect&bpo=32684]: Fix gather to propagate cancellation of itself even with return_exceptions.

bpo-33674 [https://bugs.python.org/issue?@action=redirect&bpo=33674]: Fix a race condition in SSLProtocol.connection_made() of asyncio.sslproto: start immediately the handshake instead of using call_soon(). Previously, data_received() could be called before the handshake started, causing the handshake to hang or fail.

bpo-31647 [https://bugs.python.org/issue?@action=redirect&bpo=31647]: Fixed bug where calling write_eof() on a _SelectorSocketTransport after it’s already closed raises AttributeError.

bpo-33672 [https://bugs.python.org/issue?@action=redirect&bpo=33672]: Fix Task.__repr__ crash with Cython’s bogus coroutines

bpo-33469 [https://bugs.python.org/issue?@action=redirect&bpo=33469]: Fix RuntimeError after closing loop that used run_in_executor

bpo-11874 [https://bugs.python.org/issue?@action=redirect&bpo=11874]: Use a better regex when breaking usage into wrappable parts. Avoids bogus assertion errors from custom metavar strings.

bpo-30877 [https://bugs.python.org/issue?@action=redirect&bpo=30877]: Fixed a bug in the Python implementation of the JSON decoder that prevented the cache of parsed strings from clearing after finishing the decoding. Based on patch by c-fos.

bpo-33548 [https://bugs.python.org/issue?@action=redirect&bpo=33548]: tempfile._candidate_tempdir_list should consider common TEMP locations

bpo-33542 [https://bugs.python.org/issue?@action=redirect&bpo=33542]: Prevent uuid.get_node from using a DUID instead of a MAC on Windows. Patch by Zvi Effron

bpo-26819 [https://bugs.python.org/issue?@action=redirect&bpo=26819]: Fix race condition with ReadTransport.resume_reading in Windows proactor event loop.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Minor fixes in typing module: add annotations to NamedTuple.__new__, pass *args and **kwds in Generic.__new__. Original PRs by Paulius Šarka and Chad Dombrova.

bpo-20087 [https://bugs.python.org/issue?@action=redirect&bpo=20087]: Updated alias mapping with glibc 2.27 supported locales.

bpo-33422 [https://bugs.python.org/issue?@action=redirect&bpo=33422]: Fix trailing quotation marks getting deleted when looking up byte/string literals on pydoc. Patch by Andrés Delfino.

bpo-33197 [https://bugs.python.org/issue?@action=redirect&bpo=33197]: Update error message when constructing invalid inspect.Parameters Patch by Donghee Na.

bpo-33383 [https://bugs.python.org/issue?@action=redirect&bpo=33383]: Fixed crash in the get() method of the dbm.ndbm database object when it is called with a single argument.

bpo-33329 [https://bugs.python.org/issue?@action=redirect&bpo=33329]: Fix multiprocessing regression on newer glibcs

bpo-991266 [https://bugs.python.org/issue?@action=redirect&bpo=991266]: Fix quoting of the Comment attribute of http.cookies.SimpleCookie.

bpo-33131 [https://bugs.python.org/issue?@action=redirect&bpo=33131]: Upgrade bundled version of pip to 10.0.1.

bpo-33308 [https://bugs.python.org/issue?@action=redirect&bpo=33308]: Fixed a crash in the parser module when converting an ST object to a tree of tuples or lists with line_info=False and col_info=True.

bpo-33263 [https://bugs.python.org/issue?@action=redirect&bpo=33263]: Fix FD leak in _SelectorSocketTransport Patch by Vlad Starostin.

bpo-33256 [https://bugs.python.org/issue?@action=redirect&bpo=33256]: Fix display of <module> call in the html produced by cgitb.html(). Patch by Stéphane Blondon.

bpo-33203 [https://bugs.python.org/issue?@action=redirect&bpo=33203]: random.Random.choice() now raises IndexError for empty sequences consistently even when called from subclasses without a getrandbits() implementation.

bpo-33224 [https://bugs.python.org/issue?@action=redirect&bpo=33224]: Update difflib.mdiff() for PEP 479 [https://peps.python.org/pep-0479/]. Convert an uncaught StopIteration in a generator into a return-statement.

bpo-33209 [https://bugs.python.org/issue?@action=redirect&bpo=33209]: End framing at the end of C implementation of pickle.Pickler.dump().

bpo-32861 [https://bugs.python.org/issue?@action=redirect&bpo=32861]: The urllib.robotparser’s __str__ representation now includes wildcard entries and the “Crawl-delay” and “Request-rate” fields. Patch by Michael Lazar.

bpo-33096 [https://bugs.python.org/issue?@action=redirect&bpo=33096]: Allow ttk.Treeview.insert to insert iid that has a false boolean value. Note iid=0 and iid=False would be same. Patch by Garvit Khatri.

bpo-33127 [https://bugs.python.org/issue?@action=redirect&bpo=33127]: The ssl module now compiles with LibreSSL 2.7.1.

bpo-33021 [https://bugs.python.org/issue?@action=redirect&bpo=33021]: Release the GIL during fstat() calls, avoiding hang of all threads when calling mmap.mmap(), os.urandom(), and random.seed(). Patch by Nir Soffer.

bpo-27683 [https://bugs.python.org/issue?@action=redirect&bpo=27683]: Fix a regression in ipaddress that result of hosts() is empty when the network is constructed by a tuple containing an integer mask and only 1 bit left for addresses.

bpo-32844 [https://bugs.python.org/issue?@action=redirect&bpo=32844]: Fix wrong redirection of a low descriptor (0 or 1) to stderr in subprocess if another low descriptor is closed.

bpo-31908 [https://bugs.python.org/issue?@action=redirect&bpo=31908]: Fix output of cover files for trace module command-line tool. Previously emitted cover files only when --missing option was used. Patch by Michael Selik.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: If nested log adapters are used, the inner process() methods are no longer omitted.

bpo-16865 [https://bugs.python.org/issue?@action=redirect&bpo=16865]: Support arrays >=2GiB in ctypes. Patch by Segev Finer.

bpo-31238 [https://bugs.python.org/issue?@action=redirect&bpo=31238]: pydoc: the stop() method of the private ServerThread class now waits until DocServer.serve_until_quit() completes and then explicitly sets its docserver attribute to None to break a reference cycle.

Documentation

bpo-33503 [https://bugs.python.org/issue?@action=redirect&bpo=33503]: Fix broken pypi link

bpo-33421 [https://bugs.python.org/issue?@action=redirect&bpo=33421]: Add missing documentation for typing.AsyncContextManager.

bpo-33378 [https://bugs.python.org/issue?@action=redirect&bpo=33378]: Add Korean language switcher for https://docs.python.org/3/

bpo-33276 [https://bugs.python.org/issue?@action=redirect&bpo=33276]: Clarify that the __path__ attribute on modules cannot be just any value.

bpo-33201 [https://bugs.python.org/issue?@action=redirect&bpo=33201]: Modernize documentation for writing C extension types.

bpo-33195 [https://bugs.python.org/issue?@action=redirect&bpo=33195]: Deprecate Py_UNICODE usage in c-api/arg document. Py_UNICODE related APIs are deprecated since Python 3.3, but it is missed in the document.

bpo-33126 [https://bugs.python.org/issue?@action=redirect&bpo=33126]: Document PyBuffer_ToContiguous().

bpo-27212 [https://bugs.python.org/issue?@action=redirect&bpo=27212]: Modify documentation for the islice() recipe to consume initial values up to the start index.

bpo-28247 [https://bugs.python.org/issue?@action=redirect&bpo=28247]: Update zipapp documentation to describe how to make standalone applications.

bpo-18802 [https://bugs.python.org/issue?@action=redirect&bpo=18802]: Documentation changes for ipaddress. Patch by Jon Foster and Berker Peksag.

bpo-27428 [https://bugs.python.org/issue?@action=redirect&bpo=27428]: Update documentation to clarify that WindowsRegistryFinder implements MetaPathFinder. (Patch by Himanshu Lakhara)

bpo-8243 [https://bugs.python.org/issue?@action=redirect&bpo=8243]: Add a note about curses.addch and curses.addstr exception behavior when writing outside a window, or pad.

bpo-31432 [https://bugs.python.org/issue?@action=redirect&bpo=31432]: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

Tests

bpo-33655 [https://bugs.python.org/issue?@action=redirect&bpo=33655]: Ignore test_posix_fallocate failures on BSD platforms that might be due to running on ZFS.

bpo-19417 [https://bugs.python.org/issue?@action=redirect&bpo=19417]: Add test_bdb.py.

Build

bpo-5755 [https://bugs.python.org/issue?@action=redirect&bpo=5755]: Move -Wstrict-prototypes option to CFLAGS_NODIST from OPT. This option emitted annoying warnings when building extension modules written in C++.

bpo-33614 [https://bugs.python.org/issue?@action=redirect&bpo=33614]: Ensures module definition files for the stable ABI on Windows are correctly regenerated.

bpo-33522 [https://bugs.python.org/issue?@action=redirect&bpo=33522]: Enable CI builds on Visual Studio Team Services at https://python.visualstudio.com/cpython

bpo-33012 [https://bugs.python.org/issue?@action=redirect&bpo=33012]: Add -Wno-cast-function-type for gcc 8 for silencing warnings about function casts like casting to PyCFunction in method definition lists.

bpo-33394 [https://bugs.python.org/issue?@action=redirect&bpo=33394]: Enable the verbose build for extension modules, when GNU make is passed macros on the command line.

Windows

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update Windows installer to OpenSSL 1.0.2o.

macOS

bpo-33184 [https://bugs.python.org/issue?@action=redirect&bpo=33184]: Update macOS installer build to use OpenSSL 1.0.2o.

IDLE

bpo-33656 [https://bugs.python.org/issue?@action=redirect&bpo=33656]: On Windows, add API call saying that tk scales for DPI. On Windows 8.1+ or 10, with DPI compatibility properties of the Python binary unchanged, and a monitor resolution greater than 96 DPI, this should make text and lines sharper. It should otherwise have no effect.

bpo-33768 [https://bugs.python.org/issue?@action=redirect&bpo=33768]: Clicking on a context line moves that line to the top of the editor window.

bpo-33763 [https://bugs.python.org/issue?@action=redirect&bpo=33763]: IDLE: Use read-only text widget for code context instead of label widget.

bpo-33664 [https://bugs.python.org/issue?@action=redirect&bpo=33664]: Scroll IDLE editor text by lines. Previously, the mouse wheel and scrollbar slider moved text by a fixed number of pixels, resulting in partial lines at the top of the editor box. The change also applies to the shell and grep output windows, but not to read-only text views.

bpo-33679 [https://bugs.python.org/issue?@action=redirect&bpo=33679]: Enable theme-specific color configuration for Code Context. Use the Highlights tab to see the setting for built-in themes or add settings to custom themes.

bpo-33642 [https://bugs.python.org/issue?@action=redirect&bpo=33642]: Display up to maxlines non-blank lines for Code Context. If there is no current context, show a single blank line.

bpo-33628 [https://bugs.python.org/issue?@action=redirect&bpo=33628]: IDLE: Cleanup codecontext.py and its test.

bpo-33564 [https://bugs.python.org/issue?@action=redirect&bpo=33564]: IDLE’s code context now recognizes async as a block opener.

bpo-29706 [https://bugs.python.org/issue?@action=redirect&bpo=29706]: IDLE now colors async and await as keywords in 3.6. They become full keywords in 3.7.

bpo-21474 [https://bugs.python.org/issue?@action=redirect&bpo=21474]: Update word/identifier definition from ascii to unicode. In text and entry boxes, this affects selection by double-click, movement left/right by control-left/right, and deletion left/right by control-BACKSPACE/DEL.

bpo-33204 [https://bugs.python.org/issue?@action=redirect&bpo=33204]: IDLE: consistently color invalid string prefixes. A ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’. Consistently color as much of the prefix, starting at the right, as is valid. Revise and extend colorizer test.

bpo-32831 [https://bugs.python.org/issue?@action=redirect&bpo=32831]: Add docstrings and tests for codecontext.

Tools/Demos

bpo-33189 [https://bugs.python.org/issue?@action=redirect&bpo=33189]: pygettext.py now recognizes only literal strings as docstrings and translatable strings, and rejects bytes literals and f-string expressions.

bpo-31920 [https://bugs.python.org/issue?@action=redirect&bpo=31920]: Fixed handling directories as arguments in the pygettext script. Based on patch by Oleg Krasnikov.

bpo-29673 [https://bugs.python.org/issue?@action=redirect&bpo=29673]: Fix pystackv and pystack gdbinit macros.

bpo-32885 [https://bugs.python.org/issue?@action=redirect&bpo=32885]: Add an -n flag for Tools/scripts/pathfix.py to disable automatic backup creation (files with ~ suffix).

bpo-31583 [https://bugs.python.org/issue?@action=redirect&bpo=31583]: Fix 2to3 for using with –add-suffix option but without –output-dir option for relative path to files in current directory.

C API

bpo-32374 [https://bugs.python.org/issue?@action=redirect&bpo=32374]: Document that m_traverse for multi-phase initialized modules can be called with m_state=NULL, and add a sanity check

Python 3.6.5 final

Release date: 2018-03-28

Tests

bpo-32872 [https://bugs.python.org/issue?@action=redirect&bpo=32872]: Avoid regrtest compatibility issue with namespace packages.

Build

bpo-33163 [https://bugs.python.org/issue?@action=redirect&bpo=33163]: Upgrade pip to 9.0.3 and setuptools to v39.0.1.

Python 3.6.5 release candidate 1

Release date: 2018-03-13

Security

bpo-33001 [https://bugs.python.org/issue?@action=redirect&bpo=33001]: Minimal fix to prevent buffer overrun in os.symlink on Windows

bpo-32981 [https://bugs.python.org/issue?@action=redirect&bpo=32981]: Regexes in difflib and poplib were vulnerable to catastrophic backtracking. These regexes formed potential DOS vectors (REDOS). They have been refactored. This resolves CVE 2018-1060 [https://www.cve.org/CVERecord?id=CVE-2018-1060] and CVE 2018-1061 [https://www.cve.org/CVERecord?id=CVE-2018-1061]. Patch by Jamie Davis.

Core and Builtins

bpo-33026 [https://bugs.python.org/issue?@action=redirect&bpo=33026]: Fixed jumping out of “with” block by setting f_lineno.

bpo-17288 [https://bugs.python.org/issue?@action=redirect&bpo=17288]: Prevent jumps from ‘return’ and ‘exception’ trace events.

bpo-32889 [https://bugs.python.org/issue?@action=redirect&bpo=32889]: Update Valgrind suppression list to account for the rename of Py_ADDRESS_IN_RANG to address_in_range.

bpo-32650 [https://bugs.python.org/issue?@action=redirect&bpo=32650]: Pdb and other debuggers dependent on bdb.py will correctly step over (next command) native coroutines. Patch by Pablo Galindo.

bpo-32685 [https://bugs.python.org/issue?@action=redirect&bpo=32685]: Improve suggestion when the Python 2 form of print statement is either present on the same line as the header of a compound statement or else terminated by a semi-colon instead of a newline. Patch by Nitish Chandra.

bpo-32583 [https://bugs.python.org/issue?@action=redirect&bpo=32583]: Fix possible crashing in builtin Unicode decoders caused by write out-of-bound errors when using customized decode error handlers.

bpo-26163 [https://bugs.python.org/issue?@action=redirect&bpo=26163]: Improved frozenset() hash to create more distinct hash values when faced with datasets containing many similar values.

bpo-27169 [https://bugs.python.org/issue?@action=redirect&bpo=27169]: The __debug__ constant is now optimized out at compile time. This fixes also bpo-22091 [https://bugs.python.org/issue?@action=redirect&bpo=22091].

bpo-32329 [https://bugs.python.org/issue?@action=redirect&bpo=32329]: sys.flags.hash_randomization is now properly set to 0 when hash randomization is turned off by PYTHONHASHSEED=0.

bpo-30416 [https://bugs.python.org/issue?@action=redirect&bpo=30416]: The optimizer is now protected from spending much time doing complex calculations and consuming much memory for creating large constants in constant folding.

bpo-18533 [https://bugs.python.org/issue?@action=redirect&bpo=18533]: repr() on a dict containing its own values() or items() no longer raises RecursionError; OrderedDict similarly. Instead, use ..., as for other recursive structures. Patch by Ben North.

bpo-32028 [https://bugs.python.org/issue?@action=redirect&bpo=32028]: Leading whitespace is now correctly ignored when generating suggestions for converting Py2 print statements to Py3 builtin print function calls. Patch by Sanyam Khurana.

bpo-32137 [https://bugs.python.org/issue?@action=redirect&bpo=32137]: The repr of deeply nested dict now raises a RecursionError instead of crashing due to a stack overflow.

Library

bpo-33064 [https://bugs.python.org/issue?@action=redirect&bpo=33064]: lib2to3 now properly supports trailing commas after *args and **kwargs in function signatures.

bpo-31804 [https://bugs.python.org/issue?@action=redirect&bpo=31804]: Avoid failing in multiprocessing.Process if the standard streams are closed or None at exit.

bpo-33037 [https://bugs.python.org/issue?@action=redirect&bpo=33037]: Skip sending/receiving data after SSL transport closing.

bpo-30353 [https://bugs.python.org/issue?@action=redirect&bpo=30353]: Fix ctypes pass-by-value for structs on 64-bit Cygwin/MinGW.

bpo-33009 [https://bugs.python.org/issue?@action=redirect&bpo=33009]: Fix inspect.signature() for single-parameter partialmethods.

bpo-32969 [https://bugs.python.org/issue?@action=redirect&bpo=32969]: Expose several missing constants in zlib and fix corresponding documentation.

bpo-32713 [https://bugs.python.org/issue?@action=redirect&bpo=32713]: Fixed tarfile.itn handling of out-of-bounds float values. Patch by Joffrey Fuhrer.

bpo-30622 [https://bugs.python.org/issue?@action=redirect&bpo=30622]: The ssl module now detects missing NPN support in LibreSSL.

bpo-32922 [https://bugs.python.org/issue?@action=redirect&bpo=32922]: dbm.open() now encodes filename with the filesystem encoding rather than default encoding.

bpo-32859 [https://bugs.python.org/issue?@action=redirect&bpo=32859]: In os.dup2, don’t check every call whether the dup3 syscall exists or not.

bpo-21060 [https://bugs.python.org/issue?@action=redirect&bpo=21060]: Rewrite confusing message from setup.py upload from “No dist file created in earlier command” to the more helpful “Must create and upload files in one command”.

bpo-32857 [https://bugs.python.org/issue?@action=redirect&bpo=32857]: In tkinter, after_cancel(None) now raises a ValueError instead of canceling the first scheduled function. Patch by Cheryl Sabella.

bpo-32852 [https://bugs.python.org/issue?@action=redirect&bpo=32852]: Make sure sys.argv remains as a list when running trace.

bpo-32841 [https://bugs.python.org/issue?@action=redirect&bpo=32841]: Fixed asyncio.Condition issue which silently ignored cancellation after notifying and cancelling a conditional lock. Patch by Bar Harel.

bpo-31787 [https://bugs.python.org/issue?@action=redirect&bpo=31787]: Fixed refleaks of __init__() methods in various modules. (Contributed by Oren Milman)

bpo-30157 [https://bugs.python.org/issue?@action=redirect&bpo=30157]: Fixed guessing quote and delimiter in csv.Sniffer.sniff() when only the last field is quoted. Patch by Jake Davis.

bpo-32394 [https://bugs.python.org/issue?@action=redirect&bpo=32394]: socket: Remove TCP_FASTOPEN, TCP_KEEPCNT flags on older version Windows during run-time.

bpo-32777 [https://bugs.python.org/issue?@action=redirect&bpo=32777]: Fix a rare but potential pre-exec child process deadlock in subprocess on POSIX systems when marking file descriptors inheritable on exec in the child process. This bug appears to have been introduced in 3.4.

bpo-32647 [https://bugs.python.org/issue?@action=redirect&bpo=32647]: The ctypes module used to depend on indirect linking for dlopen. The shared extension is now explicitly linked against libdl on platforms with dl.

bpo-32734 [https://bugs.python.org/issue?@action=redirect&bpo=32734]: Fixed asyncio.Lock() safety issue which allowed acquiring and locking the same lock multiple times, without it being free. Patch by Bar Harel.

bpo-32727 [https://bugs.python.org/issue?@action=redirect&bpo=32727]: Do not include name field in SMTP envelope from address. Patch by Stéphane Wirtel

bpo-27931 [https://bugs.python.org/issue?@action=redirect&bpo=27931]: Fix email address header parsing error when the username is an empty quoted string. Patch by Xiang Zhang.

bpo-32304 [https://bugs.python.org/issue?@action=redirect&bpo=32304]: distutils’ upload command no longer corrupts tar files ending with a CR byte, and no longer tries to convert CR to CRLF in any of the upload text fields.

bpo-32502 [https://bugs.python.org/issue?@action=redirect&bpo=32502]: uuid.uuid1 no longer raises an exception if a 64-bit hardware address is encountered.

bpo-31848 [https://bugs.python.org/issue?@action=redirect&bpo=31848]: Fix the error handling in Aifc_read.initfp() when the SSND chunk is not found. Patch by Zackery Spytz.

bpo-32555 [https://bugs.python.org/issue?@action=redirect&bpo=32555]: On FreeBSD and Solaris, os.strerror() now always decode the byte string from the current locale encoding, rather than using ASCII/surrogateescape in some cases.

bpo-32521 [https://bugs.python.org/issue?@action=redirect&bpo=32521]: The nis module is now compatible with new libnsl and headers location.

bpo-32473 [https://bugs.python.org/issue?@action=redirect&bpo=32473]: Improve ABCMeta._dump_registry() output readability

bpo-32521 [https://bugs.python.org/issue?@action=redirect&bpo=32521]: glibc has removed Sun RPC. Use replacement libtirpc headers and library in nis module.

bpo-32228 [https://bugs.python.org/issue?@action=redirect&bpo=32228]: Ensure that truncate() preserves the file position (as reported by tell()) after writes longer than the buffer size.

bpo-26133 [https://bugs.python.org/issue?@action=redirect&bpo=26133]: Don’t unsubscribe signals in asyncio UNIX event loop on interpreter shutdown.

bpo-32185 [https://bugs.python.org/issue?@action=redirect&bpo=32185]: The SSL module no longer sends IP addresses in SNI TLS extension on platforms with OpenSSL 1.0.2+ or inet_pton.

bpo-32323 [https://bugs.python.org/issue?@action=redirect&bpo=32323]: urllib.parse.urlsplit() does not convert zone-id (scope) to lower case for scoped IPv6 addresses in hostnames now.

bpo-32302 [https://bugs.python.org/issue?@action=redirect&bpo=32302]: Fix bdist_wininst of distutils for CRT v142: it binary compatible with CRT v140.

bpo-32255 [https://bugs.python.org/issue?@action=redirect&bpo=32255]: A single empty field is now always quoted when written into a CSV file. This allows to distinguish an empty row from a row consisting of a single empty field. Patch by Licht Takeuchi.

bpo-32277 [https://bugs.python.org/issue?@action=redirect&bpo=32277]: Raise NotImplementedError instead of SystemError on platforms where chmod(..., follow_symlinks=False) is not supported. Patch by Anthony Sottile.

bpo-32199 [https://bugs.python.org/issue?@action=redirect&bpo=32199]: The getnode() ip getter now uses ‘ip link’ instead of ‘ip link list’.

bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456]: Ensure TCP_NODELAY is set on Linux. Tests by Victor Stinner.

bpo-31900 [https://bugs.python.org/issue?@action=redirect&bpo=31900]: The locale.localeconv() function now sets temporarily the LC_CTYPE locale to the LC_NUMERIC locale to decode decimal_point and thousands_sep byte strings if they are non-ASCII or longer than 1 byte, and the LC_NUMERIC locale is different than the LC_CTYPE locale. This temporary change affects other threads. Same change for the str.format() method when formatting a number (int, float, float and subclasses) with the n type (ex: '{:n}'.format(1234)).

bpo-31802 [https://bugs.python.org/issue?@action=redirect&bpo=31802]: Importing native path module (posixpath, ntpath) now works even if the os module still is not imported.

Documentation

bpo-17232 [https://bugs.python.org/issue?@action=redirect&bpo=17232]: Clarify docs for -O and -OO. Patch by Terry Reedy.

bpo-32800 [https://bugs.python.org/issue?@action=redirect&bpo=32800]: Update link to w3c doc for xml default namespaces.

bpo-8722 [https://bugs.python.org/issue?@action=redirect&bpo=8722]: Document __getattr__() behavior when property get() method raises AttributeError.

bpo-32614 [https://bugs.python.org/issue?@action=redirect&bpo=32614]: Modify RE examples in documentation to use raw strings to prevent DeprecationWarning and add text to REGEX HOWTO to highlight the deprecation.

bpo-31972 [https://bugs.python.org/issue?@action=redirect&bpo=31972]: Improve docstrings for pathlib.PurePath subclasses.

bpo-17799 [https://bugs.python.org/issue?@action=redirect&bpo=17799]: Explain real behaviour of sys.settrace and sys.setprofile and their C-API counterparts regarding which type of events are received in each function. Patch by Pablo Galindo Salgado.

Tests

bpo-32517 [https://bugs.python.org/issue?@action=redirect&bpo=32517]: Fix failing test_asyncio on macOS 10.12.2+ due to transport of KqueueSelector loop was not being closed.

bpo-32721 [https://bugs.python.org/issue?@action=redirect&bpo=32721]: Fix test_hashlib to not fail if the _md5 module is not built.

bpo-32252 [https://bugs.python.org/issue?@action=redirect&bpo=32252]: Fix faulthandler_suppress_crash_report() used to prevent core dump files when testing crashes. getrlimit() returns zero on success.

bpo-31518 [https://bugs.python.org/issue?@action=redirect&bpo=31518]: Debian Unstable has disabled TLS 1.0 and 1.1 for SSLv23_METHOD(). Change TLS/SSL protocol of some tests to PROTOCOL_TLS or PROTOCOL_TLSv1_2 to make them pass on Debian.

Build

bpo-32635 [https://bugs.python.org/issue?@action=redirect&bpo=32635]: Fix segfault of the crypt module when libxcrypt is provided instead of libcrypt at the system.

Windows

bpo-33016 [https://bugs.python.org/issue?@action=redirect&bpo=33016]: Fix potential use of uninitialized memory in nt._getfinalpathname

bpo-32903 [https://bugs.python.org/issue?@action=redirect&bpo=32903]: Fix a memory leak in os.chdir() on Windows if the current directory is set to a UNC path.

bpo-31966 [https://bugs.python.org/issue?@action=redirect&bpo=31966]: Fixed WindowsConsoleIO.write() for writing empty data.

bpo-32409 [https://bugs.python.org/issue?@action=redirect&bpo=32409]: Ensures activate.bat can handle Unicode contents.

bpo-32457 [https://bugs.python.org/issue?@action=redirect&bpo=32457]: Improves handling of denormalized executable path when launching Python.

bpo-32370 [https://bugs.python.org/issue?@action=redirect&bpo=32370]: Use the correct encoding for ipconfig output in the uuid module. Patch by Segev Finer.

bpo-29248 [https://bugs.python.org/issue?@action=redirect&bpo=29248]: Fix os.readlink() on Windows, which was mistakenly treating the PrintNameOffset field of the reparse data buffer as a number of characters instead of bytes. Patch by Craig Holmquist and SSE4.

bpo-32588 [https://bugs.python.org/issue?@action=redirect&bpo=32588]: Create standalone _distutils_findvs module.

macOS

bpo-32726 [https://bugs.python.org/issue?@action=redirect&bpo=32726]: Provide an additional, more modern macOS installer variant that supports macOS 10.9+ systems in 64-bit mode only. Upgrade the supplied third-party libraries to OpenSSL 1.0.2n, XZ 5.2.3, and SQLite 3.22.0. The 10.9+ installer now links with and supplies its own copy of Tcl/Tk 8.6.8.

IDLE

bpo-32984 [https://bugs.python.org/issue?@action=redirect&bpo=32984]: Set __file__ while running a startup file. Like Python, IDLE optionally runs one startup file in the Shell window before presenting the first interactive input prompt. For IDLE, -s runs a file named in environmental variable IDLESTARTUP or PYTHONSTARTUP; -r file runs file. Python sets __file__ to the startup file name before running the file and unsets it before the first prompt. IDLE now does the same when run normally, without the -n option.

bpo-32940 [https://bugs.python.org/issue?@action=redirect&bpo=32940]: Simplify and rename StringTranslatePseudoMapping in pyparse.

bpo-32916 [https://bugs.python.org/issue?@action=redirect&bpo=32916]: Change str to code in pyparse.

bpo-32905 [https://bugs.python.org/issue?@action=redirect&bpo=32905]: Remove unused code in pyparse module.

bpo-32874 [https://bugs.python.org/issue?@action=redirect&bpo=32874]: Add tests for pyparse.

bpo-32837 [https://bugs.python.org/issue?@action=redirect&bpo=32837]: Using the system and place-dependent default encoding for open() is a bad idea for IDLE’s system and location-independent files.

bpo-32826 [https://bugs.python.org/issue?@action=redirect&bpo=32826]: Add “encoding=utf-8” to open() in IDLE’s test_help_about. GUI test test_file_buttons() only looks at initial ascii-only lines, but failed on systems where open() defaults to ‘ascii’ because readline() internally reads and decodes far enough ahead to encounter a non-ascii character in CREDITS.txt.

bpo-32765 [https://bugs.python.org/issue?@action=redirect&bpo=32765]: Update configdialog General tab docstring to add new widgets to the widget list.

Tools/Demos

bpo-24960 [https://bugs.python.org/issue?@action=redirect&bpo=24960]: 2to3 and lib2to3 can now read pickled grammar files using pkgutil.get_data() rather than probing the filesystem. This lets 2to3 and lib2to3 work when run from a zipfile.

bpo-32222 [https://bugs.python.org/issue?@action=redirect&bpo=32222]: Fix pygettext not extracting docstrings for functions with type annotated arguments. Patch by Toby Harradine.

C API

bpo-29084 [https://bugs.python.org/issue?@action=redirect&bpo=29084]: Undocumented C API for OrderedDict has been excluded from the limited C API. It was added by mistake and actually never worked in the limited C API.

Python 3.6.4 final

Release date: 2017-12-18

There were no new code changes in version 3.6.4 since v3.6.4rc1.

Python 3.6.4 release candidate 1

Release date: 2017-12-05

Core and Builtins

bpo-32176 [https://bugs.python.org/issue?@action=redirect&bpo=32176]: co_flags.CO_NOFREE is now always set correctly by the code object constructor based on freevars and cellvars, rather than needing to be set correctly by the caller. This ensures it will be cleared automatically when additional cell references are injected into a modified code object and function.

bpo-31949 [https://bugs.python.org/issue?@action=redirect&bpo=31949]: Fixed several issues in printing tracebacks (PyTraceBack_Print()). Setting sys.tracebacklimit to 0 or less now suppresses printing tracebacks. Setting sys.tracebacklimit to None now causes using the default limit. Setting sys.tracebacklimit to an integer larger than LONG_MAX now means using the limit LONG_MAX rather than the default limit. Fixed integer overflows in the case of more than 2**31 traceback items on Windows. Fixed output errors handling.

bpo-30696 [https://bugs.python.org/issue?@action=redirect&bpo=30696]: Fix the interactive interpreter looping endlessly when no memory.

bpo-20047 [https://bugs.python.org/issue?@action=redirect&bpo=20047]: Bytearray methods partition() and rpartition() now accept only bytes-like objects as separator, as documented. In particular they now raise TypeError rather of returning a bogus result when an integer is passed as a separator.

bpo-31852 [https://bugs.python.org/issue?@action=redirect&bpo=31852]: Fix a segmentation fault caused by a combination of the async soft keyword and continuation lines.

bpo-21720 [https://bugs.python.org/issue?@action=redirect&bpo=21720]: BytesWarning no longer emitted when the fromlist argument of __import__() or the __all__ attribute of the module contain bytes instances.

bpo-31825 [https://bugs.python.org/issue?@action=redirect&bpo=31825]: Fixed OverflowError in the ‘unicode-escape’ codec and in codecs.escape_decode() when decode an escaped non-ascii byte.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: Print the full context/cause chain of exceptions on interpreter exit, even if an exception in the chain is unhashable or compares equal to later ones. Patch by Zane Bitter.

bpo-31786 [https://bugs.python.org/issue?@action=redirect&bpo=31786]: Fix timeout rounding in the select module to round correctly negative timeouts between -1.0 and 0.0. The functions now block waiting for events as expected. Previously, the call was incorrectly non-blocking. Patch by Pablo Galindo.

bpo-31642 [https://bugs.python.org/issue?@action=redirect&bpo=31642]: Restored blocking “from package import module” by setting sys.modules[“package.module”] to None.

bpo-31626 [https://bugs.python.org/issue?@action=redirect&bpo=31626]: Fixed a bug in debug memory allocator. There was a write to freed memory after shrinking a memory block.

bpo-31619 [https://bugs.python.org/issue?@action=redirect&bpo=31619]: Fixed a ValueError when convert a string with large number of underscores to integer with binary base.

bpo-31592 [https://bugs.python.org/issue?@action=redirect&bpo=31592]: Fixed an assertion failure in Python parser in case of a bad unicodedata.normalize(). Patch by Oren Milman.

bpo-31588 [https://bugs.python.org/issue?@action=redirect&bpo=31588]: Raise a TypeError with a helpful error message when class creation fails due to a metaclass with a bad __prepare__() method. Patch by Oren Milman.

bpo-31566 [https://bugs.python.org/issue?@action=redirect&bpo=31566]: Fix an assertion failure in _warnings.warn() in case of a bad __name__ global. Patch by Oren Milman.

bpo-31505 [https://bugs.python.org/issue?@action=redirect&bpo=31505]: Fix an assertion failure in json, in case _json.make_encoder() received a bad encoder() argument. Patch by Oren Milman.

bpo-31492 [https://bugs.python.org/issue?@action=redirect&bpo=31492]: Fix assertion failures in case of failing to import from a module with a bad __name__ attribute, and in case of failing to access an attribute of such a module. Patch by Oren Milman.

bpo-31490 [https://bugs.python.org/issue?@action=redirect&bpo=31490]: Fix an assertion failure in ctypes class definition, in case the class has an attribute whose name is specified in _anonymous_ but not in _fields_. Patch by Oren Milman.

bpo-31478 [https://bugs.python.org/issue?@action=redirect&bpo=31478]: Fix an assertion failure in _random.Random.seed() in case the argument has a bad __abs__() method. Patch by Oren Milman.

bpo-31315 [https://bugs.python.org/issue?@action=redirect&bpo=31315]: Fix an assertion failure in imp.create_dynamic(), when spec.name is not a string. Patch by Oren Milman.

bpo-31311 [https://bugs.python.org/issue?@action=redirect&bpo=31311]: Fix a crash in the __setstate__() method of ctypes._CData, in case of a bad __dict__. Patch by Oren Milman.

bpo-31293 [https://bugs.python.org/issue?@action=redirect&bpo=31293]: Fix crashes in true division and multiplication of a timedelta object by a float with a bad as_integer_ratio() method. Patch by Oren Milman.

bpo-31285 [https://bugs.python.org/issue?@action=redirect&bpo=31285]: Fix an assertion failure in warnings.warn_explicit, when the return value of the received loader’s get_source() has a bad splitlines() method. Patch by Oren Milman.

bpo-30817 [https://bugs.python.org/issue?@action=redirect&bpo=30817]: PyErr_PrintEx() clears now the ignored exception that may be raised by _PySys_SetObjectId(), for example when no memory.

Library

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Two minor fixes for typing module: allow shallow copying instances of generic classes, improve interaction of __init_subclass__ with generics. Original PRs by Ivan Levkivskyi.

bpo-27240 [https://bugs.python.org/issue?@action=redirect&bpo=27240]: The header folding algorithm for the new email policies has been rewritten, which also fixes bpo-30788 [https://bugs.python.org/issue?@action=redirect&bpo=30788], bpo-31831 [https://bugs.python.org/issue?@action=redirect&bpo=31831], and bpo-32182 [https://bugs.python.org/issue?@action=redirect&bpo=32182]. In particular, RFC2231 folding is now done correctly.

bpo-32186 [https://bugs.python.org/issue?@action=redirect&bpo=32186]: io.FileIO.readall() and io.FileIO.read() now release the GIL when getting the file size. Fixed hang of all threads with inaccessible NFS server. Patch by Nir Soffer.

bpo-12239 [https://bugs.python.org/issue?@action=redirect&bpo=12239]: Make msilib.SummaryInformation.GetProperty() return None when the value of property is VT_EMPTY. Initial patch by Mark Mc Mahon.

bpo-31325 [https://bugs.python.org/issue?@action=redirect&bpo=31325]: Fix wrong usage of collections.namedtuple() in the RobotFileParser.parse() method. Initial patch by Robin Wellner.

bpo-12382 [https://bugs.python.org/issue?@action=redirect&bpo=12382]: msilib.OpenDatabase() now raises a better exception message when it couldn’t open or create an MSI file. Initial patch by William Tisäter.

bpo-32110 [https://bugs.python.org/issue?@action=redirect&bpo=32110]: codecs.StreamReader.read(n) now returns not more than n characters/bytes for non-negative n. This makes it compatible with read() methods of other file-like objects.

bpo-32072 [https://bugs.python.org/issue?@action=redirect&bpo=32072]: Fixed issues with binary plists: Fixed saving bytearrays. Identical objects will be saved only once. Equal references will be load as identical objects. Added support for saving and loading recursive data structures.

bpo-32034 [https://bugs.python.org/issue?@action=redirect&bpo=32034]: Make asyncio.IncompleteReadError and LimitOverrunError pickleable.

bpo-32015 [https://bugs.python.org/issue?@action=redirect&bpo=32015]: Fixed the looping of asyncio in the case of reconnection the socket during waiting async read/write from/to the socket.

bpo-32011 [https://bugs.python.org/issue?@action=redirect&bpo=32011]: Restored support of loading marshal files with the TYPE_INT64 code. These files can be produced in Python 2.7.

bpo-31970 [https://bugs.python.org/issue?@action=redirect&bpo=31970]: Reduce performance overhead of asyncio debug mode.

bpo-9678 [https://bugs.python.org/issue?@action=redirect&bpo=9678]: Fixed determining the MAC address in the uuid module: Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD, NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

bpo-30057 [https://bugs.python.org/issue?@action=redirect&bpo=30057]: Fix potential missed signal in signal.signal().

bpo-31933 [https://bugs.python.org/issue?@action=redirect&bpo=31933]: Fix Blake2 params leaf_size and node_offset on big endian platforms. Patch by Jack O’Connor.

bpo-31927 [https://bugs.python.org/issue?@action=redirect&bpo=31927]: Fixed compilation of the socket module on NetBSD 8. Fixed assertion failure or reading arbitrary data when parse a AF_BLUETOOTH address on NetBSD and DragonFly BSD.

bpo-27666 [https://bugs.python.org/issue?@action=redirect&bpo=27666]: Fixed stack corruption in curses.box() and curses.ungetmouse() when the size of types chtype or mmask_t is less than the size of C long. curses.box() now accepts characters as arguments. Based on patch by Steve Fink.

bpo-31897 [https://bugs.python.org/issue?@action=redirect&bpo=31897]: plistlib now catches more errors when read binary plists and raises InvalidFileException instead of unexpected exceptions.

bpo-25720 [https://bugs.python.org/issue?@action=redirect&bpo=25720]: Fix the method for checking pad state of curses WINDOW. Patch by Masayuki Yamamoto.

bpo-31893 [https://bugs.python.org/issue?@action=redirect&bpo=31893]: Fixed the layout of the kqueue_event structure on OpenBSD and NetBSD. Fixed the comparison of the kqueue_event objects.

bpo-31891 [https://bugs.python.org/issue?@action=redirect&bpo=31891]: Fixed building the curses module on NetBSD.

bpo-28416 [https://bugs.python.org/issue?@action=redirect&bpo=28416]: Instances of pickle.Pickler subclass with the persistent_id() method and pickle.Unpickler subclass with the persistent_load() method no longer create reference cycles.

bpo-28326 [https://bugs.python.org/issue?@action=redirect&bpo=28326]: Fix multiprocessing.Process when stdout and/or stderr is closed or None.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: If nested log adapters are used, the inner process() methods are no longer omitted.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: The manager property on LoggerAdapter objects is now properly settable.

bpo-31806 [https://bugs.python.org/issue?@action=redirect&bpo=31806]: Fix timeout rounding in time.sleep(), threading.Lock.acquire() and socket.socket.settimeout() to round correctly negative timeouts between -1.0 and 0.0. The functions now block waiting for events as expected. Previously, the call was incorrectly non-blocking. Patch by Pablo Galindo.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: traceback: Fix a TypeError that occurred during printing of exception tracebacks when either the current exception or an exception in its context/cause chain is unhashable. Patch by Zane Bitter.

bpo-30058 [https://bugs.python.org/issue?@action=redirect&bpo=30058]: Fixed buffer overflow in select.kqueue.control().

bpo-31770 [https://bugs.python.org/issue?@action=redirect&bpo=31770]: Prevent a crash when calling the __init__() method of a sqlite3.Cursor object more than once. Patch by Oren Milman.

bpo-31672 [https://bugs.python.org/issue?@action=redirect&bpo=31672]: idpattern in string.Template matched some non-ASCII characters. Now it uses -i regular expression local flag to avoid non-ASCII characters.

bpo-31764 [https://bugs.python.org/issue?@action=redirect&bpo=31764]: Prevent a crash in sqlite3.Cursor.close() in case the Cursor object is uninitialized. Patch by Oren Milman.

bpo-31752 [https://bugs.python.org/issue?@action=redirect&bpo=31752]: Fix possible crash in timedelta constructor called with custom integers.

bpo-31701 [https://bugs.python.org/issue?@action=redirect&bpo=31701]: On Windows, faulthandler.enable() now ignores MSC and COM exceptions.

bpo-31728 [https://bugs.python.org/issue?@action=redirect&bpo=31728]: Prevent crashes in _elementtree due to unsafe cleanup of Element.text and Element.tail. Patch by Oren Milman.

bpo-31620 [https://bugs.python.org/issue?@action=redirect&bpo=31620]: an empty asyncio.Queue now doesn’t leak memory when queue.get pollers timeout

bpo-31632 [https://bugs.python.org/issue?@action=redirect&bpo=31632]: Fix method set_protocol() of class _SSLProtocolTransport in asyncio module. This method was previously modifying a wrong reference to the protocol.

bpo-31675 [https://bugs.python.org/issue?@action=redirect&bpo=31675]: Fixed memory leaks in Tkinter’s methods splitlist() and split() when pass a string larger than 2 GiB.

bpo-31673 [https://bugs.python.org/issue?@action=redirect&bpo=31673]: Fixed typo in the name of Tkinter’s method adderrorinfo().

bpo-30806 [https://bugs.python.org/issue?@action=redirect&bpo=30806]: Fix the string representation of a netrc object.

bpo-15037 [https://bugs.python.org/issue?@action=redirect&bpo=15037]: Added a workaround for getkey() in curses for ncurses 5.7 and earlier.

bpo-25351 [https://bugs.python.org/issue?@action=redirect&bpo=25351]: Avoid venv activate failures with undefined variables

bpo-25532 [https://bugs.python.org/issue?@action=redirect&bpo=25532]: inspect.unwrap() will now only try to unwrap an object sys.getrecursionlimit() times, to protect against objects which create a new object on every attribute access.

bpo-30347 [https://bugs.python.org/issue?@action=redirect&bpo=30347]: Stop crashes when concurrently iterate over itertools.groupby() iterators.

bpo-31516 [https://bugs.python.org/issue?@action=redirect&bpo=31516]: threading.current_thread() should not return a dummy thread at shutdown.

bpo-31351 [https://bugs.python.org/issue?@action=redirect&bpo=31351]: python -m ensurepip now exits with non-zero exit code if pip bootstrapping has failed.

bpo-31482 [https://bugs.python.org/issue?@action=redirect&bpo=31482]: random.seed() now works with bytes in version=1

bpo-31334 [https://bugs.python.org/issue?@action=redirect&bpo=31334]: Fix poll.poll([timeout]) in the select module for arbitrary negative timeouts on all OSes where it can only be a non-negative integer or -1. Patch by Riccardo Coccioli.

bpo-31310 [https://bugs.python.org/issue?@action=redirect&bpo=31310]: multiprocessing’s semaphore tracker should be launched again if crashed.

bpo-31308 [https://bugs.python.org/issue?@action=redirect&bpo=31308]: Make multiprocessing’s forkserver process immune to Ctrl-C and other user interruptions. If it crashes, restart it when necessary.

Documentation

bpo-32105 [https://bugs.python.org/issue?@action=redirect&bpo=32105]: Added asyncio.BaseEventLoop.connect_accepted_socket versionadded marker.

bpo-31537 [https://bugs.python.org/issue?@action=redirect&bpo=31537]: Fix incorrect usage of get_history_length in readline documentation example code. Patch by Brad Smith.

bpo-30085 [https://bugs.python.org/issue?@action=redirect&bpo=30085]: The operator functions without double underscores are preferred for clarity. The one with underscores are only kept for back-compatibility.

Tests

bpo-31380 [https://bugs.python.org/issue?@action=redirect&bpo=31380]: Skip test_httpservers test_undecodable_file on macOS: fails on APFS.

bpo-31705 [https://bugs.python.org/issue?@action=redirect&bpo=31705]: Skip test_socket.test_sha256() on Linux kernel older than 4.5. The test fails with ENOKEY on kernel 3.10 (on ppc64le). A fix was merged into the kernel 4.5.

bpo-31174 [https://bugs.python.org/issue?@action=redirect&bpo=31174]: Fix test_tools.test_unparse: DirectoryTestCase now stores the names sample to always test the same files. It prevents false alarms when hunting reference leaks.

bpo-30695 [https://bugs.python.org/issue?@action=redirect&bpo=30695]: Add the set_nomemory(start, stop) and remove_mem_hooks() functions to the _testcapi module.

Build

bpo-32059 [https://bugs.python.org/issue?@action=redirect&bpo=32059]: detect_modules() in setup.py now also searches the sysroot paths when cross-compiling.

bpo-31957 [https://bugs.python.org/issue?@action=redirect&bpo=31957]: Fixes Windows SDK version detection when building for Windows.

bpo-31609 [https://bugs.python.org/issue?@action=redirect&bpo=31609]: Fixes quotes in PCbuild/clean.bat

bpo-31934 [https://bugs.python.org/issue?@action=redirect&bpo=31934]: Abort the build when building out of a not clean source tree.

bpo-31926 [https://bugs.python.org/issue?@action=redirect&bpo=31926]: Fixed Argument Clinic sometimes causing compilation errors when there was more than one function and/or method in a .c file with the same name.

bpo-28791 [https://bugs.python.org/issue?@action=redirect&bpo=28791]: Update Windows builds to use SQLite 3.21.0.

bpo-28791 [https://bugs.python.org/issue?@action=redirect&bpo=28791]: Update OS X installer to use SQLite 3.21.0.

bpo-22140 [https://bugs.python.org/issue?@action=redirect&bpo=22140]: Prevent double substitution of prefix in python-config.sh.

bpo-31536 [https://bugs.python.org/issue?@action=redirect&bpo=31536]: Avoid wholesale rebuild after make regen-all if nothing changed.

Windows

bpo-1102 [https://bugs.python.org/issue?@action=redirect&bpo=1102]: Return None when View.Fetch() returns ERROR_NO_MORE_ITEMS instead of raising MSIError. Initial patch by Anthony Tuininga.

bpo-31944 [https://bugs.python.org/issue?@action=redirect&bpo=31944]: Fixes Modify button in Apps and Features dialog.

macOS

bpo-31392 [https://bugs.python.org/issue?@action=redirect&bpo=31392]: Update macOS installer to use OpenSSL 1.0.2m

IDLE

bpo-32207 [https://bugs.python.org/issue?@action=redirect&bpo=32207]: Improve tk event exception tracebacks in IDLE. When tk event handling is driven by IDLE’s run loop, a confusing and distracting queue.EMPTY traceback context is no longer added to tk event exception tracebacks. The traceback is now the same as when event handling is driven by user code. Patch based on a suggestion by Serhiy Storchaka.

bpo-32164 [https://bugs.python.org/issue?@action=redirect&bpo=32164]: Delete unused file idlelib/tabbedpages.py. Use of TabbedPageSet in configdialog was replaced by ttk.Notebook.

bpo-32100 [https://bugs.python.org/issue?@action=redirect&bpo=32100]: IDLE: Fix old and new bugs in pathbrowser; improve tests. Patch mostly by Cheryl Sabella.

bpo-31858 [https://bugs.python.org/issue?@action=redirect&bpo=31858]: IDLE – Restrict shell prompt manipulation to the shell. Editor and output windows only see an empty last prompt line. This simplifies the code and fixes a minor bug when newline is inserted. Sys.ps1, if present, is read on Shell start-up, but is not set or changed.

bpo-31860 [https://bugs.python.org/issue?@action=redirect&bpo=31860]: The font sample in the IDLE configuration dialog is now editable. Changes persist while IDLE remains open

bpo-31836 [https://bugs.python.org/issue?@action=redirect&bpo=31836]: Test_code_module now passes if run after test_idle, which sets ps1. The code module uses sys.ps1 if present or sets it to ‘>>> ‘ if not. Test_code_module now properly tests both behaviors. Ditto for ps2.

bpo-28603 [https://bugs.python.org/issue?@action=redirect&bpo=28603]: Fix a TypeError that caused a shell restart when printing a traceback that includes an exception that is unhashable. Patch by Zane Bitter.

bpo-13802 [https://bugs.python.org/issue?@action=redirect&bpo=13802]: Use non-Latin characters in the IDLE’s Font settings sample. Even if one selects a font that defines a limited subset of the unicode Basic Multilingual Plane, tcl/tk will use other fonts that define a character. The expanded example give users of non-Latin characters a better idea of what they might see in IDLE’s shell and editors. To make room for the expanded sample, frames on the Font tab are re-arranged. The Font/Tabs help explains a bit about the additions.

bpo-31460 [https://bugs.python.org/issue?@action=redirect&bpo=31460]: Simplify the API of IDLE’s Module Browser. Passing a widget instead of an flist with a root widget opens the option of creating a browser frame that is only part of a window. Passing a full file name instead of pieces assumed to come from a .py file opens the possibility of browsing python files that do not end in .py.

bpo-31649 [https://bugs.python.org/issue?@action=redirect&bpo=31649]: IDLE - Make _htest, _utest parameters keyword only.

bpo-31559 [https://bugs.python.org/issue?@action=redirect&bpo=31559]: Remove test order dependence in idle_test.test_browser.

bpo-31459 [https://bugs.python.org/issue?@action=redirect&bpo=31459]: Rename IDLE’s module browser from Class Browser to Module Browser. The original module-level class and method browser became a module browser, with the addition of module-level functions, years ago. Nested classes and functions were added yesterday. For back-compatibility, the virtual event <<open-class-browser>>, which appears on the Keys tab of the Settings dialog, is not changed. Patch by Cheryl Sabella.

bpo-31500 [https://bugs.python.org/issue?@action=redirect&bpo=31500]: Default fonts now are scaled on HiDPI displays.

bpo-1612262 [https://bugs.python.org/issue?@action=redirect&bpo=1612262]: IDLE module browser now shows nested classes and functions. Original patches for code and tests by Guilherme Polo and Cheryl Sabella, respectively.

Tools/Demos

bpo-30722 [https://bugs.python.org/issue?@action=redirect&bpo=30722]: Make redemo work with Python 3.6 and newer versions. Also, remove the LOCALE option since it doesn’t work with string patterns in Python 3. Patch by Christoph Sarnowski.

C API

bpo-20891 [https://bugs.python.org/issue?@action=redirect&bpo=20891]: Fix PyGILState_Ensure(). When PyGILState_Ensure() is called in a non-Python thread before PyEval_InitThreads(), only call PyEval_InitThreads() after calling PyThreadState_New() to fix a crash.

bpo-31532 [https://bugs.python.org/issue?@action=redirect&bpo=31532]: Fix memory corruption due to allocator mix in getpath.c between Py_GetPath() and Py_SetPath()

bpo-30697 [https://bugs.python.org/issue?@action=redirect&bpo=30697]: The PyExc_RecursionErrorInst singleton is removed and PyErr_NormalizeException() does not use it anymore. This singleton is persistent and its members being never cleared may cause a segfault during finalization of the interpreter. See also bpo-22898 [https://bugs.python.org/issue?@action=redirect&bpo=22898].

Python 3.6.3 final

Release date: 2017-10-03

Library

bpo-31641 [https://bugs.python.org/issue?@action=redirect&bpo=31641]: Re-allow arbitrary iterables in concurrent.futures.as_completed(). Fixes regression in 3.6.3rc1.

Build

bpo-31662 [https://bugs.python.org/issue?@action=redirect&bpo=31662]: Fix typos in Windows uploadrelease.bat script. Fix Windows Doc build issues in Doc/make.bat.

bpo-31423 [https://bugs.python.org/issue?@action=redirect&bpo=31423]: Fix building the PDF documentation with newer versions of Sphinx.

Python 3.6.3 release candidate 1

Release date: 2017-09-18

Security

bpo-29781 [https://bugs.python.org/issue?@action=redirect&bpo=29781]: SSLObject.version() now correctly returns None when handshake over BIO has not been performed yet.

bpo-30947 [https://bugs.python.org/issue?@action=redirect&bpo=30947]: Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to get security fixes.

Core and Builtins

bpo-31471 [https://bugs.python.org/issue?@action=redirect&bpo=31471]: Fix an assertion failure in subprocess.Popen() on Windows, in case the env argument has a bad keys() method. Patch by Oren Milman.

bpo-31418 [https://bugs.python.org/issue?@action=redirect&bpo=31418]: Fix an assertion failure in PyErr_WriteUnraisable() in case of an exception with a bad __module__ attribute. Patch by Oren Milman.

bpo-31416 [https://bugs.python.org/issue?@action=redirect&bpo=31416]: Fix assertion failures in case of a bad warnings.filters or warnings.defaultaction. Patch by Oren Milman.

bpo-31411 [https://bugs.python.org/issue?@action=redirect&bpo=31411]: Raise a TypeError instead of SystemError in case warnings.onceregistry is not a dictionary. Patch by Oren Milman.

bpo-31373 [https://bugs.python.org/issue?@action=redirect&bpo=31373]: Fix several possible instances of undefined behavior due to floating-point demotions.

bpo-30465 [https://bugs.python.org/issue?@action=redirect&bpo=30465]: Location information (lineno and col_offset) in f-strings is now (mostly) correct. This fixes tools like flake8 from showing warnings on the wrong line (typically the first line of the file).

bpo-31343 [https://bugs.python.org/issue?@action=redirect&bpo=31343]: Include sys/sysmacros.h for major(), minor(), and makedev(). GNU C library plans to remove the functions from sys/types.h.

bpo-31291 [https://bugs.python.org/issue?@action=redirect&bpo=31291]: Fix an assertion failure in zipimport.zipimporter.get_data on Windows, when the return value of pathname.replace('/','\\') isn’t a string. Patch by Oren Milman.

bpo-31271 [https://bugs.python.org/issue?@action=redirect&bpo=31271]: Fix an assertion failure in the write() method of io.TextIOWrapper, when the encoder doesn’t return a bytes object. Patch by Oren Milman.

bpo-31243 [https://bugs.python.org/issue?@action=redirect&bpo=31243]: Fix a crash in some methods of io.TextIOWrapper, when the decoder’s state is invalid. Patch by Oren Milman.

bpo-30721 [https://bugs.python.org/issue?@action=redirect&bpo=30721]: print now shows correct usage hint for using Python 2 redirection syntax. Patch by Sanyam Khurana.

bpo-31070 [https://bugs.python.org/issue?@action=redirect&bpo=31070]: Fix a race condition in importlib _get_module_lock().

bpo-31095 [https://bugs.python.org/issue?@action=redirect&bpo=31095]: Fix potential crash during GC caused by tp_dealloc which doesn’t call PyObject_GC_UnTrack().

bpo-31071 [https://bugs.python.org/issue?@action=redirect&bpo=31071]: Avoid masking original TypeError in call with * unpacking when other arguments are passed.

bpo-30978 [https://bugs.python.org/issue?@action=redirect&bpo=30978]: str.format_map() now passes key lookup exceptions through. Previously any exception was replaced with a KeyError exception.

bpo-30808 [https://bugs.python.org/issue?@action=redirect&bpo=30808]: Use _Py_atomic API for concurrency-sensitive signal state.

bpo-30876 [https://bugs.python.org/issue?@action=redirect&bpo=30876]: Relative import from unloaded package now reimports the package instead of failing with SystemError. Relative import from non-package now fails with ImportError rather than SystemError.

bpo-30703 [https://bugs.python.org/issue?@action=redirect&bpo=30703]: Improve signal delivery. Avoid using Py_AddPendingCall from signal handler, to avoid calling signal-unsafe functions. The tests I’m adding here fail without the rest of the patch, on Linux and OS X. This means our signal delivery logic had defects (some signals could be lost).

bpo-30765 [https://bugs.python.org/issue?@action=redirect&bpo=30765]: Avoid blocking in pthread_mutex_lock() when PyThread_acquire_lock() is asked not to block.

bpo-31161 [https://bugs.python.org/issue?@action=redirect&bpo=31161]: Make sure the ‘Missing parentheses’ syntax error message is only applied to SyntaxError, not to subclasses. Patch by Martijn Pieters.

bpo-30814 [https://bugs.python.org/issue?@action=redirect&bpo=30814]: Fixed a race condition when import a submodule from a package.

bpo-30597 [https://bugs.python.org/issue?@action=redirect&bpo=30597]: print now shows expected input in custom error message when used as a Python 2 statement. Patch by Sanyam Khurana.

Library

bpo-31499 [https://bugs.python.org/issue?@action=redirect&bpo=31499]: xml.etree: Fix a crash when a parser is part of a reference cycle.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: typing.get_type_hints now finds the right globalns for classes and modules by default (when no globalns was specified by the caller).

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Speed improvements to the typing module. Original PRs by Ivan Levkivskyi and Mitar.

bpo-31544 [https://bugs.python.org/issue?@action=redirect&bpo=31544]: The C accelerator module of ElementTree ignored exceptions raised when looking up TreeBuilder target methods in XMLParser().

bpo-31234 [https://bugs.python.org/issue?@action=redirect&bpo=31234]: socket.create_connection() now fixes manually a reference cycle: clear the variable storing the last exception on success.

bpo-31457 [https://bugs.python.org/issue?@action=redirect&bpo=31457]: LoggerAdapter objects can now be nested.

bpo-31400 [https://bugs.python.org/issue?@action=redirect&bpo=31400]: Improves SSL error handling to avoid losing error numbers.

bpo-28958 [https://bugs.python.org/issue?@action=redirect&bpo=28958]: ssl.SSLContext() now uses OpenSSL error information when a context cannot be instantiated.

bpo-27340 [https://bugs.python.org/issue?@action=redirect&bpo=27340]: SSLSocket.sendall() now uses memoryview to create slices of data. This fixes support for all bytes-like object. It is also more efficient and avoids costly copies.

bpo-31178 [https://bugs.python.org/issue?@action=redirect&bpo=31178]: Fix string concatenation bug in rare error path in the subprocess module

bpo-31350 [https://bugs.python.org/issue?@action=redirect&bpo=31350]: Micro-optimize asyncio._get_running_loop() to become up to 10% faster.

bpo-31170 [https://bugs.python.org/issue?@action=redirect&bpo=31170]: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying of partial characters for UTF-8 input (libexpat bug 115): https://github.com/libexpat/libexpat/issues/115

bpo-29136 [https://bugs.python.org/issue?@action=redirect&bpo=29136]: Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

bpo-29212 [https://bugs.python.org/issue?@action=redirect&bpo=29212]: Fix concurrent.futures.thread.ThreadPoolExecutor threads to have a non repr() based thread name by default when no thread_name_prefix is supplied. They will now identify themselves as “ThreadPoolExecutor-y_n”.

bpo-9146 [https://bugs.python.org/issue?@action=redirect&bpo=9146]: Fix a segmentation fault in _hashopenssl when standard hash functions such as md5 are not available in the linked OpenSSL library. As in some special FIPS-140 build environments.

bpo-27144 [https://bugs.python.org/issue?@action=redirect&bpo=27144]: The map() and as_completed() iterators in concurrent.futures now avoid keeping a reference to yielded objects.

bpo-10746 [https://bugs.python.org/issue?@action=redirect&bpo=10746]: Fix ctypes producing wrong PEP 3118 [https://peps.python.org/pep-3118/] type codes for integer types.

bpo-22536 [https://bugs.python.org/issue?@action=redirect&bpo=22536]: The subprocess module now sets the filename when FileNotFoundError is raised on POSIX systems due to the executable or cwd not being found.

bpo-31249 [https://bugs.python.org/issue?@action=redirect&bpo=31249]: concurrent.futures: WorkItem.run() used by ThreadPoolExecutor now breaks a reference cycle between an exception object and the WorkItem object.

bpo-31247 [https://bugs.python.org/issue?@action=redirect&bpo=31247]: xmlrpc.server now explicitly breaks reference cycles when using sys.exc_info() in code handling exceptions.

bpo-30102 [https://bugs.python.org/issue?@action=redirect&bpo=30102]: The ssl and hashlib modules now call OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0. The function detects CPU features and enables optimizations on some CPU architectures such as POWER8. Patch is based on research from Gustavo Serra Scalet.

bpo-31185 [https://bugs.python.org/issue?@action=redirect&bpo=31185]: Fixed miscellaneous errors in asyncio speedup module.

bpo-31135 [https://bugs.python.org/issue?@action=redirect&bpo=31135]: ttk: fix the destroy() method of LabeledScale and OptionMenu classes. Call the parent destroy() method even if the used attribute doesn’t exist. The LabeledScale.destroy() method now also explicitly clears label and scale attributes to help the garbage collector to destroy all widgets.

bpo-31107 [https://bugs.python.org/issue?@action=redirect&bpo=31107]: Fix copyreg._slotnames() mangled attribute calculation for classes whose name begins with an underscore. Patch by Shane Harvey.

bpo-31061 [https://bugs.python.org/issue?@action=redirect&bpo=31061]: Fixed a crash when using asyncio and threads.

bpo-30502 [https://bugs.python.org/issue?@action=redirect&bpo=30502]: Fix handling of long oids in ssl. Based on patch by Christian Heimes.

bpo-30119 [https://bugs.python.org/issue?@action=redirect&bpo=30119]: ftplib.FTP.putline() now throws ValueError on commands that contains CR or LF. Patch by Donghee Na.

bpo-30595 [https://bugs.python.org/issue?@action=redirect&bpo=30595]: multiprocessing.Queue.get() with a timeout now polls its reader in non-blocking mode if it succeeded to acquire the lock but the acquire took longer than the timeout.

bpo-29403 [https://bugs.python.org/issue?@action=redirect&bpo=29403]: Fix unittest.mock’s autospec to not fail on method-bound builtin functions. Patch by Aaron Gallagher.

bpo-30961 [https://bugs.python.org/issue?@action=redirect&bpo=30961]: Fix decrementing a borrowed reference in tracemalloc.

bpo-25684 [https://bugs.python.org/issue?@action=redirect&bpo=25684]: Change ttk.OptionMenu radiobuttons to be unique across instances of OptionMenu.

bpo-30886 [https://bugs.python.org/issue?@action=redirect&bpo=30886]: Fix multiprocessing.Queue.join_thread(): it now waits until the thread completes, even if the thread was started by the same process which created the queue.

bpo-29854 [https://bugs.python.org/issue?@action=redirect&bpo=29854]: Fix segfault in readline when using readline’s history-size option. Patch by Nir Soffer.

bpo-30319 [https://bugs.python.org/issue?@action=redirect&bpo=30319]: socket.close() now ignores ECONNRESET error.

bpo-30828 [https://bugs.python.org/issue?@action=redirect&bpo=30828]: Fix out of bounds write in asyncio.CFuture.remove_done_callback().

bpo-30807 [https://bugs.python.org/issue?@action=redirect&bpo=30807]: signal.setitimer() may disable the timer when passed a tiny value. Tiny values (such as 1e-6) are valid non-zero values for setitimer(), which is specified as taking microsecond-resolution intervals. However, on some platform, our conversion routine could convert 1e-6 into a zero interval, therefore disabling the timer instead of (re-)scheduling it.

bpo-30441 [https://bugs.python.org/issue?@action=redirect&bpo=30441]: Fix bug when modifying os.environ while iterating over it

bpo-30532 [https://bugs.python.org/issue?@action=redirect&bpo=30532]: Fix email header value parser dropping folding white space in certain cases.

bpo-30879 [https://bugs.python.org/issue?@action=redirect&bpo=30879]: os.listdir() and os.scandir() now emit bytes names when called with bytes-like argument.

bpo-30746 [https://bugs.python.org/issue?@action=redirect&bpo=30746]: Prohibited the ‘=’ character in environment variable names in os.putenv() and os.spawn*().

bpo-29755 [https://bugs.python.org/issue?@action=redirect&bpo=29755]: Fixed the lgettext() family of functions in the gettext module. They now always return bytes.

Documentation

bpo-31294 [https://bugs.python.org/issue?@action=redirect&bpo=31294]: Fix incomplete code snippet in the ZeroMQSocketListener and ZeroMQSocketHandler examples and adapt them to Python 3.

bpo-21649 [https://bugs.python.org/issue?@action=redirect&bpo=21649]: Add RFC 7525 and Mozilla server side TLS links to SSL documentation.

bpo-30803 [https://bugs.python.org/issue?@action=redirect&bpo=30803]: Clarify doc on truth value testing. Original patch by Peter Thomassen.

Tests

bpo-31320 [https://bugs.python.org/issue?@action=redirect&bpo=31320]: Silence traceback in test_ssl

bpo-25674 [https://bugs.python.org/issue?@action=redirect&bpo=25674]: Remove sha256.tbs-internet.com ssl test

bpo-30715 [https://bugs.python.org/issue?@action=redirect&bpo=30715]: Address ALPN callback changes for OpenSSL 1.1.0f. The latest version behaves like OpenSSL 1.0.2 and no longer aborts handshake.

bpo-30822 [https://bugs.python.org/issue?@action=redirect&bpo=30822]: regrtest: Exclude tzdata from regrtest –all. When running the test suite using –use=all / -u all, exclude tzdata since it makes test_datetime too slow (15-20 min on some buildbots) which then times out on some buildbots. Fix also regrtest command line parser to allow passing -u extralargefile to run test_zipfile64.

Build

bpo-30854 [https://bugs.python.org/issue?@action=redirect&bpo=30854]: Fix compile error when compiling –without-threads. Patch by Masayuki Yamamoto.

Windows

bpo-30389 [https://bugs.python.org/issue?@action=redirect&bpo=30389]: Adds detection of Visual Studio 2017 to distutils on Windows.

bpo-31340 [https://bugs.python.org/issue?@action=redirect&bpo=31340]: Change to building with MSVC v141 (included with Visual Studio 2017)

bpo-30581 [https://bugs.python.org/issue?@action=redirect&bpo=30581]: os.cpu_count() now returns the correct number of processors on Windows when the number of logical processors is greater than 64.

bpo-30731 [https://bugs.python.org/issue?@action=redirect&bpo=30731]: Add a missing xmlns to python.manifest so that it matches the schema.

IDLE

bpo-31493 [https://bugs.python.org/issue?@action=redirect&bpo=31493]: IDLE code context – fix code update and font update timers. Canceling timers prevents a warning message when test_idle completes.

bpo-31488 [https://bugs.python.org/issue?@action=redirect&bpo=31488]: IDLE - Update non-key options in former extension classes. When applying configdialog changes, call .reload for each feature class. Change ParenMatch so updated options affect existing instances attached to existing editor windows.

bpo-31477 [https://bugs.python.org/issue?@action=redirect&bpo=31477]: IDLE - Improve rstrip entry in doc. Strip trailing whitespace strips more than blank spaces. Multiline string literals are not skipped.

bpo-31480 [https://bugs.python.org/issue?@action=redirect&bpo=31480]: IDLE - make tests pass with zzdummy extension disabled by default.

bpo-31421 [https://bugs.python.org/issue?@action=redirect&bpo=31421]: Document how IDLE runs tkinter programs. IDLE calls tcl/tk update in the background in order to make live interaction and experimentation with tkinter applications much easier.

bpo-31414 [https://bugs.python.org/issue?@action=redirect&bpo=31414]: IDLE – fix tk entry box tests by deleting first. Adding to an int entry is not the same as deleting and inserting because int(‘’) will fail.

bpo-31051 [https://bugs.python.org/issue?@action=redirect&bpo=31051]: Rearrange IDLE configdialog GenPage into Window, Editor, and Help sections.

bpo-30617 [https://bugs.python.org/issue?@action=redirect&bpo=30617]: IDLE - Add docstrings and tests for outwin subclass of editor. Move some data and functions from the class to module level. Patch by Cheryl Sabella.

bpo-31287 [https://bugs.python.org/issue?@action=redirect&bpo=31287]: IDLE - Do not modify tkinter.message in test_configdialog.

bpo-27099 [https://bugs.python.org/issue?@action=redirect&bpo=27099]: Convert IDLE’s built-in ‘extensions’ to regular features. About 10 IDLE features were implemented as supposedly optional extensions. Their different behavior could be confusing or worse for users and not good for maintenance. Hence the conversion. The main difference for users is that user configurable key bindings for builtin features are now handled uniformly. Now, editing a binding in a keyset only affects its value in the keyset. All bindings are defined together in the system-specific default keysets in config-extensions.def. All custom keysets are saved as a whole in config-extension.cfg. All take effect as soon as one clicks Apply or Ok. The affected events are ‘<<force-open-completions>>’, ‘<<expand-word>>’, ‘<<force-open-calltip>>’, ‘<<flash-paren>>’, ‘<<format-paragraph>>’, ‘<<run-module>>’, ‘<<check-module>>’, and ‘<<zoom-height>>’. Any (global) customizations made before 3.6.3 will not affect their keyset-specific customization after 3.6.3. and vice versa. Initial patch by Charles Wohlganger.

bpo-31206 [https://bugs.python.org/issue?@action=redirect&bpo=31206]: IDLE: Factor HighPage(Frame) class from ConfigDialog. Patch by Cheryl Sabella.

bpo-31001 [https://bugs.python.org/issue?@action=redirect&bpo=31001]: Add tests for configdialog highlight tab. Patch by Cheryl Sabella.

bpo-31205 [https://bugs.python.org/issue?@action=redirect&bpo=31205]: IDLE: Factor KeysPage(Frame) class from ConfigDialog. The slightly modified tests continue to pass. Patch by Cheryl Sabella.

bpo-31130 [https://bugs.python.org/issue?@action=redirect&bpo=31130]: IDLE – stop leaks in test_configdialog. Initial patch by Victor Stinner.

bpo-31002 [https://bugs.python.org/issue?@action=redirect&bpo=31002]: Add tests for configdialog keys tab. Patch by Cheryl Sabella.

bpo-19903 [https://bugs.python.org/issue?@action=redirect&bpo=19903]: IDLE: Calltips use inspect.signature instead of inspect.getfullargspec. This improves calltips for builtins converted to use Argument Clinic. Patch by Louie Lu.

bpo-31083 [https://bugs.python.org/issue?@action=redirect&bpo=31083]: IDLE - Add an outline of a TabPage class in configdialog. Update existing classes to match outline. Initial patch by Cheryl Sabella.

bpo-31050 [https://bugs.python.org/issue?@action=redirect&bpo=31050]: Factor GenPage(Frame) class from ConfigDialog. The slightly modified tests continue to pass. Patch by Cheryl Sabella.

bpo-31004 [https://bugs.python.org/issue?@action=redirect&bpo=31004]: IDLE - Factor FontPage(Frame) class from ConfigDialog. Slightly modified tests continue to pass. Fix General tests. Patch mostly by Cheryl Sabella.

bpo-30781 [https://bugs.python.org/issue?@action=redirect&bpo=30781]: IDLE - Use ttk widgets in ConfigDialog. Patches by Terry Jan Reedy and Cheryl Sabella.

bpo-31060 [https://bugs.python.org/issue?@action=redirect&bpo=31060]: IDLE - Finish rearranging methods of ConfigDialog Grouping methods pertaining to each tab and the buttons will aid writing tests and improving the tabs and will enable splitting the groups into classes.

bpo-30853 [https://bugs.python.org/issue?@action=redirect&bpo=30853]: IDLE – Factor a VarTrace class out of ConfigDialog. Instance tracers manages pairs consisting of a tk variable and a callback function. When tracing is turned on, setting the variable calls the function. Test coverage for the new class is 100%.

bpo-31003 [https://bugs.python.org/issue?@action=redirect&bpo=31003]: IDLE: Add more tests for General tab.

bpo-30993 [https://bugs.python.org/issue?@action=redirect&bpo=30993]: IDLE - Improve configdialog font page and tests. In configdialog: Document causal pathways in create_font_tab docstring. Simplify some attribute names. Move set_samples calls to var_changed_font (idea from Cheryl Sabella). Move related functions to positions after the create widgets function. In test_configdialog: Fix test_font_set so not order dependent. Fix renamed test_indent_scale so it tests the widget. Adjust tests for movement of set_samples call. Add tests for load functions. Put all font tests in one class and tab indent tests in another. Except for two lines, these tests completely cover the related functions.

bpo-30981 [https://bugs.python.org/issue?@action=redirect&bpo=30981]: IDLE – Add more configdialog font page tests.

bpo-28523 [https://bugs.python.org/issue?@action=redirect&bpo=28523]: IDLE: replace ‘colour’ with ‘color’ in configdialog.

bpo-30917 [https://bugs.python.org/issue?@action=redirect&bpo=30917]: Add tests for idlelib.config.IdleConf. Increase coverage from 46% to 96%. Patch by Louie Lu.

bpo-30934 [https://bugs.python.org/issue?@action=redirect&bpo=30934]: Document coverage details for idlelib tests. Add section to idlelib/idle-test/README.txt. Include check that branches are taken both ways. Exclude IDLE-specific code that does not run during unit tests.

bpo-30913 [https://bugs.python.org/issue?@action=redirect&bpo=30913]: IDLE: Document ConfigDialog tk Vars, methods, and widgets in docstrings This will facilitate improving the dialog and splitting up the class. Original patch by Cheryl Sabella.

bpo-30899 [https://bugs.python.org/issue?@action=redirect&bpo=30899]: IDLE: Add tests for ConfigParser subclasses in config. Patch by Louie Lu.

bpo-30881 [https://bugs.python.org/issue?@action=redirect&bpo=30881]: IDLE: Add docstrings to browser.py. Patch by Cheryl Sabella.

bpo-30851 [https://bugs.python.org/issue?@action=redirect&bpo=30851]: IDLE: Remove unused variables in configdialog. One is a duplicate, one is set but cannot be altered by users. Patch by Cheryl Sabella.

bpo-30870 [https://bugs.python.org/issue?@action=redirect&bpo=30870]: IDLE: In Settings dialog, select font with Up, Down keys as well as mouse. Initial patch by Louie Lu.

bpo-8231 [https://bugs.python.org/issue?@action=redirect&bpo=8231]: IDLE: call config.IdleConf.GetUserCfgDir only once.

bpo-30779 [https://bugs.python.org/issue?@action=redirect&bpo=30779]: IDLE: Factor ConfigChanges class from configdialog, put in config; test. * In config, put dump test code in a function; run it and unittest in ‘if __name__ == ‘__main__’. * Add class config.ConfigChanges based on changes_class_v4.py on bpo issue. * Add class test_config.ChangesTest, partly using configdialog_tests_v1.py. * Revise configdialog to use ConfigChanges; see tracker msg297804. * Revise test_configdialog to match configdialog changes. * Remove configdialog functions unused or moved to ConfigChanges. Cheryl Sabella contributed parts of the patch.

bpo-30777 [https://bugs.python.org/issue?@action=redirect&bpo=30777]: IDLE: configdialog - Add docstrings and fix comments. Patch by Cheryl Sabella.

bpo-30495 [https://bugs.python.org/issue?@action=redirect&bpo=30495]: IDLE: Improve textview with docstrings, PEP8 names, and more tests. Patch by Cheryl Sabella.

bpo-30723 [https://bugs.python.org/issue?@action=redirect&bpo=30723]: IDLE: Make several improvements to parenmatch. Add ‘parens’ style to highlight both opener and closer. Make ‘default’ style, which is not default, a synonym for ‘opener’. Make time-delay work the same with all styles. Add help for config dialog extensions tab, including help for parenmatch. Add new tests. Original patch by Charles Wohlganger.

bpo-30674 [https://bugs.python.org/issue?@action=redirect&bpo=30674]: IDLE: add docstrings to grep module. Patch by Cheryl Sabella

bpo-21519 [https://bugs.python.org/issue?@action=redirect&bpo=21519]: IDLE’s basic custom key entry dialog now detects duplicates properly. Original patch by Saimadhav Heblikar.

bpo-29910 [https://bugs.python.org/issue?@action=redirect&bpo=29910]: IDLE no longer deletes a character after commenting out a region by a key shortcut. Add return 'break' for this and other potential conflicts between IDLE and default key bindings.

bpo-30728 [https://bugs.python.org/issue?@action=redirect&bpo=30728]: Review and change idlelib.configdialog names. Lowercase method and attribute names. Replace ‘colour’ with ‘color’, expand overly cryptic names, delete unneeded underscores. Replace import * with specific imports. Patches by Cheryl Sabella.

bpo-6739 [https://bugs.python.org/issue?@action=redirect&bpo=6739]: IDLE: Verify user-entered key sequences by trying to bind them with tk. Add tests for all 3 validation functions. Original patch by G Polo. Tests added by Cheryl Sabella.

Tools/Demos

bpo-30983 [https://bugs.python.org/issue?@action=redirect&bpo=30983]: gdb integration commands (py-bt, etc.) work on optimized shared builds now, too. PEP 523 [https://peps.python.org/pep-0523/] introduced _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on non-debug shared builds. This broke the ability to use py-bt, py-up, and a few other Python-specific gdb integrations. The problem is fixed by only looking for _PyEval_EvalFrameDefault frames in python-gdb.py. Original patch by Bruno “Polaco” Penteado.

Python 3.6.2 final

Release date: 2017-07-17

No changes since release candidate 2

Python 3.6.2 release candidate 2

Release date: 2017-07-07

Security

bpo-30730 [https://bugs.python.org/issue?@action=redirect&bpo=30730]: Prevent environment variables injection in subprocess on Windows. Prevent passing other environment variables and command arguments.

bpo-30694 [https://bugs.python.org/issue?@action=redirect&bpo=30694]: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of multiple security vulnerabilities including: CVE 2017-9233 [https://www.cve.org/CVERecord?id=CVE-2017-9233] (External entity infinite loop DoS), CVE 2016-9063 [https://www.cve.org/CVERecord?id=CVE-2016-9063] (Integer overflow, re-fix), CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] (Fix regression bugs from 2.2.0’s fix to CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718]) and CVE 2012-0876 [https://www.cve.org/CVERecord?id=CVE-2012-0876] (Counter hash flooding with SipHash). Note: the CVE 2016-5300 [https://www.cve.org/CVERecord?id=CVE-2016-5300] (Use os-specific entropy sources like getrandom) doesn’t impact Python, since Python already gets entropy from the OS to set the expat secret using XML_SetHashSalt().

bpo-30500 [https://bugs.python.org/issue?@action=redirect&bpo=30500]: Fix urllib.parse.splithost() to correctly parse fragments. For example, splithost('//127.0.0.1#@evil.com/') now correctly returns the 127.0.0.1 host, instead of treating @evil.com as the host in an authentication (login@host).

Python 3.6.2 release candidate 1

Release date: 2017-06-17

Security

bpo-29591 [https://bugs.python.org/issue?@action=redirect&bpo=29591]: Update expat copy from 2.1.1 to 2.2.0 to get fixes of CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] and CVE 2016-4472 [https://www.cve.org/CVERecord?id=CVE-2016-4472]. See https://sourceforge.net/p/expat/bugs/537/ for more information.

Core and Builtins

bpo-30682 [https://bugs.python.org/issue?@action=redirect&bpo=30682]: Removed a too-strict assertion that failed for certain f-strings, such as eval(“f’\n’”) and eval(“f’\r’”).

bpo-30604 [https://bugs.python.org/issue?@action=redirect&bpo=30604]: Move co_extra_freefuncs to not be per-thread to avoid crashes

bpo-29104 [https://bugs.python.org/issue?@action=redirect&bpo=29104]: Fixed parsing backslashes in f-strings.

bpo-27945 [https://bugs.python.org/issue?@action=redirect&bpo=27945]: Fixed various segfaults with dict when input collections are mutated during searching, inserting or comparing. Based on patches by Duane Griffin and Tim Mitchell.

bpo-25794 [https://bugs.python.org/issue?@action=redirect&bpo=25794]: Fixed type.__setattr__() and type.__delattr__() for non-interned attribute names. Based on patch by Eryk Sun.

bpo-30039 [https://bugs.python.org/issue?@action=redirect&bpo=30039]: If a KeyboardInterrupt happens when the interpreter is in the middle of resuming a chain of nested ‘yield from’ or ‘await’ calls, it’s now correctly delivered to the innermost frame.

bpo-12414 [https://bugs.python.org/issue?@action=redirect&bpo=12414]: sys.getsizeof() on a code object now returns the sizes which includes the code struct and sizes of objects which it references. Patch by Donghee Na.

bpo-29949 [https://bugs.python.org/issue?@action=redirect&bpo=29949]: Fix memory usage regression of set and frozenset object.

bpo-29935 [https://bugs.python.org/issue?@action=redirect&bpo=29935]: Fixed error messages in the index() method of tuple, list and deque when pass indices of wrong type.

bpo-29859 [https://bugs.python.org/issue?@action=redirect&bpo=29859]: Show correct error messages when any of the pthread_* calls in thread_pthread.h fails.

bpo-28876 [https://bugs.python.org/issue?@action=redirect&bpo=28876]: bool(range) works even if len(range) raises OverflowError.

bpo-29600 [https://bugs.python.org/issue?@action=redirect&bpo=29600]: Fix wrapping coroutine return values in StopIteration.

bpo-28856 [https://bugs.python.org/issue?@action=redirect&bpo=28856]: Fix an oversight that %b format for bytes should support objects follow the buffer protocol.

bpo-29714 [https://bugs.python.org/issue?@action=redirect&bpo=29714]: Fix a regression that bytes format may fail when containing zero bytes inside.

bpo-29478 [https://bugs.python.org/issue?@action=redirect&bpo=29478]: If max_line_length=None is specified while using the Compat32 policy, it is no longer ignored. Patch by Mircea Cosbuc.

Library

bpo-30616 [https://bugs.python.org/issue?@action=redirect&bpo=30616]: Functional API of enum allows to create empty enums. Patched by Donghee Na

bpo-30038 [https://bugs.python.org/issue?@action=redirect&bpo=30038]: Fix race condition between signal delivery and wakeup file descriptor. Patch by Nathaniel Smith.

bpo-23894 [https://bugs.python.org/issue?@action=redirect&bpo=23894]: lib2to3 now recognizes rb'...' and f'...' strings.

bpo-23890 [https://bugs.python.org/issue?@action=redirect&bpo=23890]: unittest.TestCase.assertRaises() now manually breaks a reference cycle to not keep objects alive longer than expected.

bpo-30149 [https://bugs.python.org/issue?@action=redirect&bpo=30149]: inspect.signature() now supports callables with variable-argument parameters wrapped with partialmethod. Patch by Donghee Na.

bpo-30645 [https://bugs.python.org/issue?@action=redirect&bpo=30645]: Fix path calculation in imp.load_package(), fixing it for cases when a package is only shipped with bytecodes. Patch by Alexandru Ardelean.

bpo-29931 [https://bugs.python.org/issue?@action=redirect&bpo=29931]: Fixed comparison check for ipaddress.ip_interface objects. Patch by Sanjay Sundaresan.

bpo-30605 [https://bugs.python.org/issue?@action=redirect&bpo=30605]: re.compile() no longer raises a BytesWarning when compiling a bytes instance with misplaced inline modifier. Patch by Roy Williams.

bpo-24484 [https://bugs.python.org/issue?@action=redirect&bpo=24484]: Avoid race condition in multiprocessing cleanup (#2159)

bpo-28994 [https://bugs.python.org/issue?@action=redirect&bpo=28994]: The traceback no longer displayed for SystemExit raised in a callback registered by atexit.

bpo-30508 [https://bugs.python.org/issue?@action=redirect&bpo=30508]: Don’t log exceptions if Task/Future “cancel()” method was called.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Updates to typing module: Add generic AsyncContextManager, add support for ContextManager on all versions. Original PRs by Jelle Zijlstra and Ivan Levkivskyi

bpo-29870 [https://bugs.python.org/issue?@action=redirect&bpo=29870]: Fix ssl sockets leaks when connection is aborted in asyncio/ssl implementation. Patch by Michaël Sghaïer.

bpo-29743 [https://bugs.python.org/issue?@action=redirect&bpo=29743]: Closing transport during handshake process leaks open socket. Patch by Nikolay Kim

bpo-27585 [https://bugs.python.org/issue?@action=redirect&bpo=27585]: Fix waiter cancellation in asyncio.Lock. Patch by Mathieu Sornay.

bpo-30418 [https://bugs.python.org/issue?@action=redirect&bpo=30418]: On Windows, subprocess.Popen.communicate() now also ignore EINVAL on stdin.write() if the child process is still running but closed the pipe.

bpo-29822 [https://bugs.python.org/issue?@action=redirect&bpo=29822]: inspect.isabstract() now works during __init_subclass__. Patch by Nate Soares.

bpo-29581 [https://bugs.python.org/issue?@action=redirect&bpo=29581]: ABCMeta.__new__ now accepts **kwargs, allowing abstract base classes to use keyword parameters in __init_subclass__. Patch by Nate Soares.

bpo-30557 [https://bugs.python.org/issue?@action=redirect&bpo=30557]: faulthandler now correctly filters and displays exception codes on Windows

bpo-30378 [https://bugs.python.org/issue?@action=redirect&bpo=30378]: Fix the problem that logging.handlers.SysLogHandler cannot handle IPv6 addresses.

bpo-29960 [https://bugs.python.org/issue?@action=redirect&bpo=29960]: Preserve generator state when _random.Random.setstate() raises an exception. Patch by Bryan Olson.

bpo-30414 [https://bugs.python.org/issue?@action=redirect&bpo=30414]: multiprocessing.Queue._feed background running thread do not break from main loop on exception.

bpo-30003 [https://bugs.python.org/issue?@action=redirect&bpo=30003]: Fix handling escape characters in HZ codec. Based on patch by Ma Lin.

bpo-30301 [https://bugs.python.org/issue?@action=redirect&bpo=30301]: Fix AttributeError when using SimpleQueue.empty() under spawn and forkserver start methods.

bpo-30329 [https://bugs.python.org/issue?@action=redirect&bpo=30329]: imaplib and poplib now catch the Windows socket WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid operation was attempted. This error occurs sometimes on SSL connections.

bpo-30375 [https://bugs.python.org/issue?@action=redirect&bpo=30375]: Warnings emitted when compile a regular expression now always point to the line in the user code. Previously they could point into inners of the re module if emitted from inside of groups or conditionals.

bpo-30048 [https://bugs.python.org/issue?@action=redirect&bpo=30048]: Fixed Task.cancel() can be ignored when the task is running coroutine and the coroutine returned without any more await.

bpo-30266 [https://bugs.python.org/issue?@action=redirect&bpo=30266]: contextlib.AbstractContextManager now supports anti-registration by setting __enter__ = None or __exit__ = None, following the pattern introduced in bpo-25958 [https://bugs.python.org/issue?@action=redirect&bpo=25958]. Patch by Jelle Zijlstra.

bpo-30298 [https://bugs.python.org/issue?@action=redirect&bpo=30298]: Weaken the condition of deprecation warnings for inline modifiers. Now allowed several subsequential inline modifiers at the start of the pattern (e.g. '(?i)(?s)...'). In verbose mode whitespaces and comments now are allowed before and between inline modifiers (e.g. '(?x) (?i) (?s)...').

bpo-29990 [https://bugs.python.org/issue?@action=redirect&bpo=29990]: Fix range checking in GB18030 decoder. Original patch by Ma Lin.

bpo-26293 [https://bugs.python.org/issue?@action=redirect&bpo=26293]: Change resulted because of zipfile breakage. (See also: bpo-29094 [https://bugs.python.org/issue?@action=redirect&bpo=29094])

bpo-30243 [https://bugs.python.org/issue?@action=redirect&bpo=30243]: Removed the __init__ methods of _json’s scanner and encoder. Misusing them could cause memory leaks or crashes. Now scanner and encoder objects are completely initialized in the __new__ methods.

bpo-30185 [https://bugs.python.org/issue?@action=redirect&bpo=30185]: Avoid KeyboardInterrupt tracebacks in forkserver helper process when Ctrl-C is received.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: add typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes. Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

bpo-30205 [https://bugs.python.org/issue?@action=redirect&bpo=30205]: Fix getsockname() for unbound AF_UNIX sockets on Linux.

bpo-30070 [https://bugs.python.org/issue?@action=redirect&bpo=30070]: Fixed leaks and crashes in errors handling in the parser module.

bpo-30061 [https://bugs.python.org/issue?@action=redirect&bpo=30061]: Fixed crashes in IOBase methods __next__() and readlines() when readline() or __next__() respectively return non-sizeable object. Fixed possible other errors caused by not checking results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

bpo-30017 [https://bugs.python.org/issue?@action=redirect&bpo=30017]: Allowed calling the close() method of the zip entry writer object multiple times. Writing to a closed writer now always produces a ValueError.

bpo-30068 [https://bugs.python.org/issue?@action=redirect&bpo=30068]: _io._IOBase.readlines will check if it’s closed first when hint is present.

bpo-29694 [https://bugs.python.org/issue?@action=redirect&bpo=29694]: Fixed race condition in pathlib mkdir with flags parents=True. Patch by Armin Rigo.

bpo-29692 [https://bugs.python.org/issue?@action=redirect&bpo=29692]: Fixed arbitrary unchaining of RuntimeError exceptions in contextlib.contextmanager. Patch by Siddharth Velankar.

bpo-29998 [https://bugs.python.org/issue?@action=redirect&bpo=29998]: Pickling and copying ImportError now preserves name and path attributes.

bpo-29953 [https://bugs.python.org/issue?@action=redirect&bpo=29953]: Fixed memory leaks in the replace() method of datetime and time objects when pass out of bound fold argument.

bpo-29942 [https://bugs.python.org/issue?@action=redirect&bpo=29942]: Fix a crash in itertools.chain.from_iterable when encountering long runs of empty iterables.

bpo-27863 [https://bugs.python.org/issue?@action=redirect&bpo=27863]: Fixed multiple crashes in ElementTree caused by race conditions and wrong types.

bpo-28699 [https://bugs.python.org/issue?@action=redirect&bpo=28699]: Fixed a bug in pools in multiprocessing.pool that raising an exception at the very first of an iterable may swallow the exception or make the program hang. Patch by Davin Potts and Xiang Zhang.

bpo-25803 [https://bugs.python.org/issue?@action=redirect&bpo=25803]: Avoid incorrect errors raised by Path.mkdir(exist_ok=True) when the OS gives priority to errors such as EACCES over EEXIST.

bpo-29861 [https://bugs.python.org/issue?@action=redirect&bpo=29861]: Release references to tasks, their arguments and their results as soon as they are finished in multiprocessing.Pool.

bpo-29884 [https://bugs.python.org/issue?@action=redirect&bpo=29884]: faulthandler: Restore the old sigaltstack during teardown. Patch by Christophe Zeitouny.

bpo-25455 [https://bugs.python.org/issue?@action=redirect&bpo=25455]: Fixed crashes in repr of recursive buffered file-like objects.

bpo-29800 [https://bugs.python.org/issue?@action=redirect&bpo=29800]: Fix crashes in partial.__repr__ if the keys of partial.keywords are not strings. Patch by Michael Seifert.

bpo-29742 [https://bugs.python.org/issue?@action=redirect&bpo=29742]: get_extra_info() raises exception if get called on closed ssl transport. Patch by Nikolay Kim.

bpo-8256 [https://bugs.python.org/issue?@action=redirect&bpo=8256]: Fixed possible failing or crashing input() if attributes “encoding” or “errors” of sys.stdin or sys.stdout are not set or are not strings.

bpo-28298 [https://bugs.python.org/issue?@action=redirect&bpo=28298]: Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from accepting big intables (objects that have __int__) as elements. Patch by Oren Milman.

bpo-28231 [https://bugs.python.org/issue?@action=redirect&bpo=28231]: The zipfile module now accepts path-like objects for external paths.

bpo-26915 [https://bugs.python.org/issue?@action=redirect&bpo=26915]: index() and count() methods of collections.abc.Sequence now check identity before checking equality when do comparisons.

bpo-29615 [https://bugs.python.org/issue?@action=redirect&bpo=29615]: SimpleXMLRPCDispatcher no longer chains KeyError (or any other exception) to exception(s) raised in the dispatched methods. Patch by Petr Motejlek.

bpo-30177 [https://bugs.python.org/issue?@action=redirect&bpo=30177]: path.resolve(strict=False) no longer cuts the path after the first element not present in the filesystem. Patch by Antoine Pietri.

IDLE

bpo-15786 [https://bugs.python.org/issue?@action=redirect&bpo=15786]: Fix several problems with IDLE’s autocompletion box. The following should now work: clicking on selection box items; using the scrollbar; selecting an item by hitting Return. Hangs on MacOSX should no longer happen. Patch by Louie Lu.

bpo-25514 [https://bugs.python.org/issue?@action=redirect&bpo=25514]: Add doc subsubsection about IDLE failure to start. Popup no-connection message directs users to this section.

bpo-30642 [https://bugs.python.org/issue?@action=redirect&bpo=30642]: Fix reference leaks in IDLE tests. Patches by Louie Lu and Terry Jan Reedy.

bpo-30495 [https://bugs.python.org/issue?@action=redirect&bpo=30495]: Add docstrings for textview.py and use PEP8 names. Patches by Cheryl Sabella and Terry Jan Reedy.

bpo-30290 [https://bugs.python.org/issue?@action=redirect&bpo=30290]: Help-about: use pep8 names and add tests. Increase coverage to 100%. Patches by Louie Lu, Cheryl Sabella, and Terry Jan Reedy.

bpo-30303 [https://bugs.python.org/issue?@action=redirect&bpo=30303]: Add _utest option to textview; add new tests. Increase coverage to 100%. Patches by Louie Lu and Terry Jan Reedy.

C API

bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867]: Function PySlice_GetIndicesEx() no longer replaced with a macro if Py_LIMITED_API is not set.

Build

bpo-29941 [https://bugs.python.org/issue?@action=redirect&bpo=29941]: Add --with-assertions configure flag to explicitly enable C assert() checks. Defaults to off. --with-pydebug implies --with-assertions.

bpo-28787 [https://bugs.python.org/issue?@action=redirect&bpo=28787]: Fix out-of-tree builds of Python when configured with --with--dtrace.

bpo-29243 [https://bugs.python.org/issue?@action=redirect&bpo=29243]: Prevent unnecessary rebuilding of Python during make test, make install and some other make targets when configured with --enable-optimizations.

bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404]: Don’t regenerate generated files based on file modification time anymore: the action is now explicit. Replace make touch with make regen-all.

bpo-29643 [https://bugs.python.org/issue?@action=redirect&bpo=29643]: Fix --enable-optimization didn’t work.

Documentation

bpo-30176 [https://bugs.python.org/issue?@action=redirect&bpo=30176]: Add missing attribute related constants in curses documentation.

bpo-30052 [https://bugs.python.org/issue?@action=redirect&bpo=30052]: the link targets for bytes() and bytearray() are now their respective type definitions, rather than the corresponding builtin function entries. Use bytes and bytearray to reference the latter. In order to ensure this and future cross-reference updates are applied automatically, the daily documentation builds now disable the default output caching features in Sphinx.

bpo-26985 [https://bugs.python.org/issue?@action=redirect&bpo=26985]: Add missing info of code object in inspect documentation.

Tools/Demos

bpo-29367 [https://bugs.python.org/issue?@action=redirect&bpo=29367]: python-gdb.py now supports also method-wrapper (wrapperobject) objects.

Tests

bpo-30357 [https://bugs.python.org/issue?@action=redirect&bpo=30357]: test_thread: setUp() now uses support.threading_setup() and support.threading_cleanup() to wait until threads complete to avoid random side effects on following tests. Initial patch written by Grzegorz Grzywacz.

bpo-30197 [https://bugs.python.org/issue?@action=redirect&bpo=30197]: Enhanced functions swap_attr() and swap_item() in the test.support module. They now work when delete replaced attribute or item inside the with statement. The old value of the attribute or item (or None if it doesn’t exist) now will be assigned to the target of the “as” clause, if there is one.

Windows

bpo-30687 [https://bugs.python.org/issue?@action=redirect&bpo=30687]: Locate msbuild.exe on Windows when building rather than vcvarsall.bat

bpo-30450 [https://bugs.python.org/issue?@action=redirect&bpo=30450]: The build process on Windows no longer depends on Subversion, instead pulling external code from GitHub via a Python script. If Python 3.6 is not found on the system (via py -3.6), NuGet is used to download a copy of 32-bit Python.

Python 3.6.1 final

Release date: 2017-03-21

Core and Builtins

bpo-29723 [https://bugs.python.org/issue?@action=redirect&bpo=29723]: The sys.path[0] initialization change for bpo-29139 [https://bugs.python.org/issue?@action=redirect&bpo=29139] caused a regression by revealing an inconsistency in how sys.path is initialized when executing __main__ from a zipfile, directory, or other import location. The interpreter now consistently avoids ever adding the import location’s parent directory to sys.path, and ensures no other sys.path entries are inadvertently modified when inserting the import location named on the command line.

Build

bpo-27593 [https://bugs.python.org/issue?@action=redirect&bpo=27593]: fix format of git information used in sys.version

Fix incompatible comment in python.h

Python 3.6.1 release candidate 1

Release date: 2017-03-04

Core and Builtins

bpo-28893 [https://bugs.python.org/issue?@action=redirect&bpo=28893]: Set correct __cause__ for errors about invalid awaitables returned from __aiter__ and __anext__.

bpo-29683 [https://bugs.python.org/issue?@action=redirect&bpo=29683]: Fixes to memory allocation in _PyCode_SetExtra. Patch by Brian Coleman.

bpo-29684 [https://bugs.python.org/issue?@action=redirect&bpo=29684]: Fix minor regression of PyEval_CallObjectWithKeywords. It should raise TypeError when kwargs is not a dict. But it might cause segv when args=NULL and kwargs is not a dict.

bpo-28598 [https://bugs.python.org/issue?@action=redirect&bpo=28598]: Support __rmod__ for subclasses of str being called before str.__mod__. Patch by Martijn Pieters.

bpo-29607 [https://bugs.python.org/issue?@action=redirect&bpo=29607]: Fix stack_effect computation for CALL_FUNCTION_EX. Patch by Matthieu Dartiailh.

bpo-29602 [https://bugs.python.org/issue?@action=redirect&bpo=29602]: Fix incorrect handling of signed zeros in complex constructor for complex subclasses and for inputs having a __complex__ method. Patch by Serhiy Storchaka.

bpo-29347 [https://bugs.python.org/issue?@action=redirect&bpo=29347]: Fixed possibly dereferencing undefined pointers when creating weakref objects.

bpo-29438 [https://bugs.python.org/issue?@action=redirect&bpo=29438]: Fixed use-after-free problem in key sharing dict.

bpo-29319 [https://bugs.python.org/issue?@action=redirect&bpo=29319]: Prevent RunMainFromImporter overwriting sys.path[0].

bpo-29337 [https://bugs.python.org/issue?@action=redirect&bpo=29337]: Fixed possible BytesWarning when compare the code objects. Warnings could be emitted at compile time.

bpo-29327 [https://bugs.python.org/issue?@action=redirect&bpo=29327]: Fixed a crash when pass the iterable keyword argument to sorted().

bpo-29034 [https://bugs.python.org/issue?@action=redirect&bpo=29034]: Fix memory leak and use-after-free in os module (path_converter).

bpo-29159 [https://bugs.python.org/issue?@action=redirect&bpo=29159]: Fix regression in bytes(x) when x.__index__() raises Exception.

bpo-28932 [https://bugs.python.org/issue?@action=redirect&bpo=28932]: Do not include <sys/random.h> if it does not exist.

bpo-25677 [https://bugs.python.org/issue?@action=redirect&bpo=25677]: Correct the positioning of the syntax error caret for indented blocks. Based on patch by Michael Layzell.

bpo-29000 [https://bugs.python.org/issue?@action=redirect&bpo=29000]: Fixed bytes formatting of octals with zero padding in alternate form.

bpo-26919 [https://bugs.python.org/issue?@action=redirect&bpo=26919]: On Android, operating system data is now always encoded/decoded to/from UTF-8, instead of the locale encoding to avoid inconsistencies with os.fsencode() and os.fsdecode() which are already using UTF-8.

bpo-28991 [https://bugs.python.org/issue?@action=redirect&bpo=28991]: functools.lru_cache() was susceptible to an obscure reentrancy bug triggerable by a monkey-patched len() function.

bpo-28739 [https://bugs.python.org/issue?@action=redirect&bpo=28739]: f-string expressions are no longer accepted as docstrings and by ast.literal_eval() even if they do not include expressions.

bpo-28512 [https://bugs.python.org/issue?@action=redirect&bpo=28512]: Fixed setting the offset attribute of SyntaxError by PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

bpo-28918 [https://bugs.python.org/issue?@action=redirect&bpo=28918]: Fix the cross compilation of xxlimited when Python has been built with Py_DEBUG defined.

bpo-28731 [https://bugs.python.org/issue?@action=redirect&bpo=28731]: Optimize _PyDict_NewPresized() to create correct size dict. Improve speed of dict literal with constant keys up to 30%.

Library

bpo-29169 [https://bugs.python.org/issue?@action=redirect&bpo=29169]: Update zlib to 1.2.11.

bpo-29623 [https://bugs.python.org/issue?@action=redirect&bpo=29623]: Allow use of path-like object as a single argument in ConfigParser.read(). Patch by David Ellis.

bpo-28963 [https://bugs.python.org/issue?@action=redirect&bpo=28963]: Fix out of bound iteration in asyncio.Future.remove_done_callback implemented in C.

bpo-29704 [https://bugs.python.org/issue?@action=redirect&bpo=29704]: asyncio.subprocess.SubprocessStreamProtocol no longer closes before all pipes are closed.

bpo-29271 [https://bugs.python.org/issue?@action=redirect&bpo=29271]: Fix Task.current_task and Task.all_tasks implemented in C to accept None argument as their pure Python implementation.

bpo-29703 [https://bugs.python.org/issue?@action=redirect&bpo=29703]: Fix asyncio to support instantiation of new event loops in child processes.

bpo-29376 [https://bugs.python.org/issue?@action=redirect&bpo=29376]: Fix assertion error in threading._DummyThread.is_alive().

bpo-28624 [https://bugs.python.org/issue?@action=redirect&bpo=28624]: Add a test that checks that cwd parameter of Popen() accepts PathLike objects. Patch by Sayan Chowdhury.

bpo-28518 [https://bugs.python.org/issue?@action=redirect&bpo=28518]: Start a transaction implicitly before a DML statement. Patch by Aviv Palivoda.

bpo-29532 [https://bugs.python.org/issue?@action=redirect&bpo=29532]: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation.

bpo-29110 [https://bugs.python.org/issue?@action=redirect&bpo=29110]: Fix file object leak in aifc.open() when file is given as a filesystem path and is not in valid AIFF format. Patch by Anthony Zhang.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: typing.Counter, typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

bpo-29100 [https://bugs.python.org/issue?@action=redirect&bpo=29100]: Fix datetime.fromtimestamp() regression introduced in Python 3.6.0: check minimum and maximum years.

bpo-29519 [https://bugs.python.org/issue?@action=redirect&bpo=29519]: Fix weakref spewing exceptions during interpreter shutdown when used with a rare combination of multiprocessing and custom codecs.

bpo-29416 [https://bugs.python.org/issue?@action=redirect&bpo=29416]: Prevent infinite loop in pathlib.Path.mkdir

bpo-29444 [https://bugs.python.org/issue?@action=redirect&bpo=29444]: Fixed out-of-bounds buffer access in the group() method of the match object. Based on patch by WGH.

bpo-29335 [https://bugs.python.org/issue?@action=redirect&bpo=29335]: Fix subprocess.Popen.wait() when the child process has exited to a stopped instead of terminated state (ex: when under ptrace).

bpo-29290 [https://bugs.python.org/issue?@action=redirect&bpo=29290]: Fix a regression in argparse that help messages would wrap at non-breaking spaces.

bpo-28735 [https://bugs.python.org/issue?@action=redirect&bpo=28735]: Fixed the comparison of mock.MagickMock with mock.ANY.

bpo-29316 [https://bugs.python.org/issue?@action=redirect&bpo=29316]: Restore the provisional status of typing module, add corresponding note to documentation. Patch by Ivan L.

bpo-29219 [https://bugs.python.org/issue?@action=redirect&bpo=29219]: Fixed infinite recursion in the repr of uninitialized ctypes.CDLL instances.

bpo-29011 [https://bugs.python.org/issue?@action=redirect&bpo=29011]: Fix an important omission by adding Deque to the typing module.

bpo-28969 [https://bugs.python.org/issue?@action=redirect&bpo=28969]: Fixed race condition in C implementation of functools.lru_cache. KeyError could be raised when cached function with full cache was simultaneously called from different threads with the same uncached arguments.

bpo-29142 [https://bugs.python.org/issue?@action=redirect&bpo=29142]: In urllib.request, suffixes in no_proxy environment variable with leading dots could match related hostnames again (e.g. .b.c matches a.b.c). Patch by Milan Oberkirch.

bpo-28961 [https://bugs.python.org/issue?@action=redirect&bpo=28961]: Fix unittest.mock._Call helper: don’t ignore the name parameter anymore. Patch written by Jiajun Huang.

bpo-29203 [https://bugs.python.org/issue?@action=redirect&bpo=29203]: functools.lru_cache() now respects PEP 468 [https://peps.python.org/pep-0468/] and preserves the order of keyword arguments. f(a=1, b=2) is now cached separately from f(b=2, a=1) since both calls could potentially give different results.

bpo-15812 [https://bugs.python.org/issue?@action=redirect&bpo=15812]: inspect.getframeinfo() now correctly shows the first line of a context. Patch by Sam Breese.

bpo-29094 [https://bugs.python.org/issue?@action=redirect&bpo=29094]: Offsets in a ZIP file created with extern file object and modes “w” and “x” now are relative to the start of the file.

bpo-29085 [https://bugs.python.org/issue?@action=redirect&bpo=29085]: Allow random.Random.seed() to use high quality OS randomness rather than the pid and time.

bpo-29061 [https://bugs.python.org/issue?@action=redirect&bpo=29061]: Fixed bug in secrets.randbelow() which would hang when given a negative input. Patch by Brendan Donegan.

bpo-29079 [https://bugs.python.org/issue?@action=redirect&bpo=29079]: Prevent infinite loop in pathlib.resolve() on Windows

bpo-13051 [https://bugs.python.org/issue?@action=redirect&bpo=13051]: Fixed recursion errors in large or resized curses.textpad.Textbox. Based on patch by Tycho Andersen.

bpo-29119 [https://bugs.python.org/issue?@action=redirect&bpo=29119]: Fix weakrefs in the pure python version of collections.OrderedDict move_to_end() method. Contributed by Andra Bogildea.

bpo-9770 [https://bugs.python.org/issue?@action=redirect&bpo=9770]: curses.ascii predicates now work correctly with negative integers.

bpo-28427 [https://bugs.python.org/issue?@action=redirect&bpo=28427]: old keys should not remove new values from WeakValueDictionary when collecting from another thread.

bpo-28923 [https://bugs.python.org/issue?@action=redirect&bpo=28923]: Remove editor artifacts from Tix.py.

bpo-29055 [https://bugs.python.org/issue?@action=redirect&bpo=29055]: Neaten-up empty population error on random.choice() by suppressing the upstream exception.

bpo-28871 [https://bugs.python.org/issue?@action=redirect&bpo=28871]: Fixed a crash when deallocate deep ElementTree.

bpo-19542 [https://bugs.python.org/issue?@action=redirect&bpo=19542]: Fix bugs in WeakValueDictionary.setdefault() and WeakValueDictionary.pop() when a GC collection happens in another thread.

bpo-20191 [https://bugs.python.org/issue?@action=redirect&bpo=20191]: Fixed a crash in resource.prlimit() when passing a sequence that doesn’t own its elements as limits.

bpo-28779 [https://bugs.python.org/issue?@action=redirect&bpo=28779]: multiprocessing.set_forkserver_preload() would crash the forkserver process if a preloaded module instantiated some multiprocessing objects such as locks.

bpo-28847 [https://bugs.python.org/issue?@action=redirect&bpo=28847]: dbm.dumb now supports reading read-only files and no longer writes the index file when it is not changed.

bpo-26937 [https://bugs.python.org/issue?@action=redirect&bpo=26937]: The chown() method of the tarfile.TarFile class does not fail now when the grp module cannot be imported, as for example on Android platforms.

IDLE

bpo-29071 [https://bugs.python.org/issue?@action=redirect&bpo=29071]: IDLE colors f-string prefixes (but not invalid ur prefixes).

bpo-28572 [https://bugs.python.org/issue?@action=redirect&bpo=28572]: Add 10% to coverage of IDLE’s test_configdialog. Update and augment description of the configuration system.

Windows

bpo-29579 [https://bugs.python.org/issue?@action=redirect&bpo=29579]: Removes readme.txt from the installer

bpo-29326 [https://bugs.python.org/issue?@action=redirect&bpo=29326]: Ignores blank lines in ._pth files (Patch by Alexey Izbyshev)

bpo-28164 [https://bugs.python.org/issue?@action=redirect&bpo=28164]: Correctly handle special console filenames (patch by Eryk Sun)

bpo-29409 [https://bugs.python.org/issue?@action=redirect&bpo=29409]: Implement PEP 529 [https://peps.python.org/pep-0529/] for io.FileIO (Patch by Eryk Sun)

bpo-29392 [https://bugs.python.org/issue?@action=redirect&bpo=29392]: Prevent crash when passing invalid arguments into msvcrt module.

bpo-25778 [https://bugs.python.org/issue?@action=redirect&bpo=25778]: winreg does not truncate string correctly (Patch by Eryk Sun)

bpo-28896 [https://bugs.python.org/issue?@action=redirect&bpo=28896]: Deprecate WindowsRegistryFinder and disable it by default.

C API

bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867]: Function PySlice_GetIndicesEx() is replaced with a macro if Py_LIMITED_API is not set or set to the value between 0x03050400 and 0x03060000 (not including) or 0x03060100 or higher.

bpo-29083 [https://bugs.python.org/issue?@action=redirect&bpo=29083]: Fixed the declaration of some public API functions. PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and Py_BuildValue() were not available in limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

bpo-29058 [https://bugs.python.org/issue?@action=redirect&bpo=29058]: All stable API extensions added after Python 3.2 are now available only when Py_LIMITED_API is set to the PY_VERSION_HEX value of the minimum Python version supporting this API.

Documentation

bpo-28929 [https://bugs.python.org/issue?@action=redirect&bpo=28929]: Link the documentation to its source file on GitHub.

bpo-25008 [https://bugs.python.org/issue?@action=redirect&bpo=25008]: Document smtpd.py as effectively deprecated and add a pointer to aiosmtpd, a third-party asyncio-based replacement.

bpo-26355 [https://bugs.python.org/issue?@action=redirect&bpo=26355]: Add canonical header link on each page to corresponding major version of the documentation. Patch by Matthias Bussonnier.

bpo-29349 [https://bugs.python.org/issue?@action=redirect&bpo=29349]: Fix Python 2 syntax in code for building the documentation.

Tests

bpo-28087 [https://bugs.python.org/issue?@action=redirect&bpo=28087]: Skip test_asyncore and test_eintr poll failures on macOS. Skip some tests of select.poll when running on macOS due to unresolved issues with the underlying system poll function on some macOS versions.

bpo-29571 [https://bugs.python.org/issue?@action=redirect&bpo=29571]: to match the behaviour of the re.LOCALE flag, test_re.test_locale_flag now uses locale.getpreferredencoding(False) to determine the candidate encoding for the test regex (allowing it to correctly skip the test when the default locale encoding is a multi-byte encoding)

bpo-28950 [https://bugs.python.org/issue?@action=redirect&bpo=28950]: Disallow -j0 to be combined with -T/-l in regrtest command line arguments.

bpo-28683 [https://bugs.python.org/issue?@action=redirect&bpo=28683]: Fix the tests that bind() a unix socket and raise PermissionError on Android for a non-root user.

bpo-26939 [https://bugs.python.org/issue?@action=redirect&bpo=26939]: Add the support.setswitchinterval() function to fix test_functools hanging on the Android armv7 qemu emulator.

Build

bpo-27593 [https://bugs.python.org/issue?@action=redirect&bpo=27593]: sys.version and the platform module python_build(), python_branch(), and python_revision() functions now use git information rather than hg when building from a repo.

bpo-29572 [https://bugs.python.org/issue?@action=redirect&bpo=29572]: Update Windows build and OS X installers to use OpenSSL 1.0.2k.

bpo-26851 [https://bugs.python.org/issue?@action=redirect&bpo=26851]: Set Android compilation and link flags.

bpo-28768 [https://bugs.python.org/issue?@action=redirect&bpo=28768]: Fix implicit declaration of function _setmode. Patch by Masayuki Yamamoto

bpo-29080 [https://bugs.python.org/issue?@action=redirect&bpo=29080]: Removes hard dependency on hg.exe from PCBuild/build.bat

bpo-23903 [https://bugs.python.org/issue?@action=redirect&bpo=23903]: Added missed names to PC/python3.def.

bpo-28762 [https://bugs.python.org/issue?@action=redirect&bpo=28762]: lockf() is available on Android API level 24, but the F_LOCK macro is not defined in android-ndk-r13.

bpo-28538 [https://bugs.python.org/issue?@action=redirect&bpo=28538]: Fix the compilation error that occurs because if_nameindex() is available on Android API level 24, but the if_nameindex structure is not defined.

bpo-20211 [https://bugs.python.org/issue?@action=redirect&bpo=20211]: Do not add the directory for installing C header files and the directory for installing object code libraries to the cross compilation search paths. Original patch by Thomas Petazzoni.

bpo-28849 [https://bugs.python.org/issue?@action=redirect&bpo=28849]: Do not define sys.implementation._multiarch on Android.

Python 3.6.0 final

Release date: 2016-12-23

No changes since release candidate 2

Python 3.6.0 release candidate 2

Release date: 2016-12-16

Core and Builtins

bpo-28147 [https://bugs.python.org/issue?@action=redirect&bpo=28147]: Fix a memory leak in split-table dictionaries: setattr() must not convert combined table into split table. Patch written by INADA Naoki.

bpo-28990 [https://bugs.python.org/issue?@action=redirect&bpo=28990]: Fix asyncio SSL hanging if connection is closed before handshake is completed. (Patch by HoHo-Ho)

Tools/Demos

bpo-28770 [https://bugs.python.org/issue?@action=redirect&bpo=28770]: Fix python-gdb.py for fastcalls.

Windows

bpo-28896 [https://bugs.python.org/issue?@action=redirect&bpo=28896]: Deprecate WindowsRegistryFinder.

Build

bpo-28898 [https://bugs.python.org/issue?@action=redirect&bpo=28898]: Prevent gdb build errors due to HAVE_LONG_LONG redefinition.

Python 3.6.0 release candidate 1

Release date: 2016-12-06

Core and Builtins

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: Rather than silently producing a class that doesn’t support zero-argument super() in methods, failing to pass the new __classcell__ namespace entry up to type.__new__ now results in a DeprecationWarning and a class that supports zero-argument super().

bpo-28797 [https://bugs.python.org/issue?@action=redirect&bpo=28797]: Modifying the class __dict__ inside the __set_name__ method of a descriptor that is used inside that class no longer prevents calling the __set_name__ method of other descriptors.

bpo-28782 [https://bugs.python.org/issue?@action=redirect&bpo=28782]: Fix a bug in the implementation yield from when checking if the next instruction is YIELD_FROM. Regression introduced by WORDCODE (bpo-26647 [https://bugs.python.org/issue?@action=redirect&bpo=26647]).

Library

bpo-27030 [https://bugs.python.org/issue?@action=redirect&bpo=27030]: Unknown escapes in re.sub() replacement template are allowed again. But they still are deprecated and will be disabled in 3.7.

bpo-28835 [https://bugs.python.org/issue?@action=redirect&bpo=28835]: Fix a regression introduced in warnings.catch_warnings(): call warnings.showwarning() if it was overridden inside the context manager.

bpo-27172 [https://bugs.python.org/issue?@action=redirect&bpo=27172]: To assist with upgrades from 2.7, the previously documented deprecation of inspect.getfullargspec() has been reversed. This decision may be revisited again after the Python 2.7 branch is no longer officially supported.

bpo-26273 [https://bugs.python.org/issue?@action=redirect&bpo=26273]: Add new socket.TCP_CONGESTION (Linux 2.6.13) and socket.TCP_USER_TIMEOUT (Linux 2.6.37) constants. Patch written by Omar Sandoval.

bpo-24142 [https://bugs.python.org/issue?@action=redirect&bpo=24142]: Reading a corrupt config file left configparser in an invalid state. Original patch by Florian Höch.

bpo-28843 [https://bugs.python.org/issue?@action=redirect&bpo=28843]: Fix asyncio C Task to handle exceptions __traceback__.

C API

bpo-28808 [https://bugs.python.org/issue?@action=redirect&bpo=28808]: PyUnicode_CompareWithASCIIString() now never raises exceptions.

Documentation

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: The data model reference and the porting section in the What’s New guide now cover the additional __classcell__ handling needed for custom metaclasses to fully support PEP 487 [https://peps.python.org/pep-0487/] and zero-argument super().

Tools/Demos

bpo-28023 [https://bugs.python.org/issue?@action=redirect&bpo=28023]: Fix python-gdb.py didn’t support new dict implementation.

Python 3.6.0 beta 4

Release date: 2016-11-21

Core and Builtins

bpo-28532 [https://bugs.python.org/issue?@action=redirect&bpo=28532]: Show sys.version when -V option is supplied twice.

bpo-27100 [https://bugs.python.org/issue?@action=redirect&bpo=27100]: The with-statement now checks for __enter__ before it checks for __exit__. This gives less confusing error messages when both methods are missing. Patch by Jonathan Ellington.

bpo-28746 [https://bugs.python.org/issue?@action=redirect&bpo=28746]: Fix the set_inheritable() file descriptor method on platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

bpo-26920 [https://bugs.python.org/issue?@action=redirect&bpo=26920]: Fix not getting the locale’s charset upon initializing the interpreter, on platforms that do not have langinfo.

bpo-28648 [https://bugs.python.org/issue?@action=redirect&bpo=28648]: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X when decode astral characters. Patch by Xiang Zhang.

bpo-19398 [https://bugs.python.org/issue?@action=redirect&bpo=19398]: Extra slash no longer added to sys.path components in case of empty compile-time PYTHONPATH components.

bpo-28665 [https://bugs.python.org/issue?@action=redirect&bpo=28665]: Improve speed of the STORE_DEREF opcode by 40%.

bpo-28583 [https://bugs.python.org/issue?@action=redirect&bpo=28583]: PyDict_SetDefault didn’t combine split table when needed. Patch by Xiang Zhang.

bpo-27243 [https://bugs.python.org/issue?@action=redirect&bpo=27243]: Change PendingDeprecationWarning -> DeprecationWarning. As it was agreed in the issue, __aiter__ returning an awaitable should result in PendingDeprecationWarning in 3.5 and in DeprecationWarning in 3.6.

bpo-26182 [https://bugs.python.org/issue?@action=redirect&bpo=26182]: Fix a refleak in code that raises DeprecationWarning.

bpo-28721 [https://bugs.python.org/issue?@action=redirect&bpo=28721]: Fix asynchronous generators aclose() and athrow() to handle StopAsyncIteration propagation properly.

Library

bpo-28752 [https://bugs.python.org/issue?@action=redirect&bpo=28752]: Restored the __reduce__() methods of datetime objects.

bpo-28727 [https://bugs.python.org/issue?@action=redirect&bpo=28727]: Regular expression patterns, _sre.SRE_Pattern objects created by re.compile(), become comparable (only x==y and x!=y operators). This change should fix the bpo-18383 [https://bugs.python.org/issue?@action=redirect&bpo=18383]: don’t duplicate warning filters when the warnings module is reloaded (thing usually only done in unit tests).

bpo-20572 [https://bugs.python.org/issue?@action=redirect&bpo=20572]: The subprocess.Popen.wait method’s undocumented endtime parameter now raises a DeprecationWarning.

bpo-25659 [https://bugs.python.org/issue?@action=redirect&bpo=25659]: In ctypes, prevent a crash calling the from_buffer() and from_buffer_copy() methods on abstract classes like Array.

bpo-19717 [https://bugs.python.org/issue?@action=redirect&bpo=19717]: Makes Path.resolve() succeed on paths that do not exist. Patch by Vajrasky Kok

bpo-28563 [https://bugs.python.org/issue?@action=redirect&bpo=28563]: Fixed possible DoS and arbitrary code execution when handle plural form selections in the gettext module. The expression parser now supports exact syntax supported by GNU gettext.

bpo-28387 [https://bugs.python.org/issue?@action=redirect&bpo=28387]: Fixed possible crash in _io.TextIOWrapper deallocator when the garbage collector is invoked in other thread. Based on patch by Sebastian Cufre.

bpo-28600 [https://bugs.python.org/issue?@action=redirect&bpo=28600]: Optimize loop.call_soon.

bpo-28613 [https://bugs.python.org/issue?@action=redirect&bpo=28613]: Fix get_event_loop() return the current loop if called from coroutines/callbacks.

bpo-28634 [https://bugs.python.org/issue?@action=redirect&bpo=28634]: Fix asyncio.isfuture() to support unittest.Mock.

bpo-26081 [https://bugs.python.org/issue?@action=redirect&bpo=26081]: Fix refleak in _asyncio.Future.__iter__().throw.

bpo-28639 [https://bugs.python.org/issue?@action=redirect&bpo=28639]: Fix inspect.isawaitable to always return bool Patch by Justin Mayfield.

bpo-28652 [https://bugs.python.org/issue?@action=redirect&bpo=28652]: Make loop methods reject socket kinds they do not support.

bpo-28653 [https://bugs.python.org/issue?@action=redirect&bpo=28653]: Fix a refleak in functools.lru_cache.

bpo-28703 [https://bugs.python.org/issue?@action=redirect&bpo=28703]: Fix asyncio.iscoroutinefunction to handle Mock objects.

bpo-28704 [https://bugs.python.org/issue?@action=redirect&bpo=28704]: Fix create_unix_server to support Path-like objects (PEP 519).

bpo-28720 [https://bugs.python.org/issue?@action=redirect&bpo=28720]: Add collections.abc.AsyncGenerator.

Documentation

bpo-28513 [https://bugs.python.org/issue?@action=redirect&bpo=28513]: Documented command-line interface of zipfile.

Tests

bpo-28666 [https://bugs.python.org/issue?@action=redirect&bpo=28666]: Now test.support.rmtree is able to remove unwritable or unreadable directories.

bpo-23839 [https://bugs.python.org/issue?@action=redirect&bpo=23839]: Various caches now are cleared before running every test file.

Build

bpo-10656 [https://bugs.python.org/issue?@action=redirect&bpo=10656]: Fix out-of-tree building on AIX. Patch by Tristan Carel and Michael Haubenwallner.

bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359]: Rename –with-optimiations to –enable-optimizations.

bpo-28676 [https://bugs.python.org/issue?@action=redirect&bpo=28676]: Prevent missing ‘getentropy’ declaration warning on macOS. Patch by Gareth Rees.

Python 3.6.0 beta 3

Release date: 2016-10-31

Core and Builtins

bpo-28128 [https://bugs.python.org/issue?@action=redirect&bpo=28128]: Deprecation warning for invalid str and byte escape sequences now prints better information about where the error occurs. Patch by Serhiy Storchaka and Eric Smith.

bpo-28509 [https://bugs.python.org/issue?@action=redirect&bpo=28509]: dict.update() no longer allocate unnecessary large memory.

bpo-28426 [https://bugs.python.org/issue?@action=redirect&bpo=28426]: Fixed potential crash in PyUnicode_AsDecodedObject() in debug build.

bpo-28517 [https://bugs.python.org/issue?@action=redirect&bpo=28517]: Fixed of-by-one error in the peephole optimizer that caused keeping unreachable code.

bpo-28214 [https://bugs.python.org/issue?@action=redirect&bpo=28214]: Improved exception reporting for problematic __set_name__ attributes.

bpo-23782 [https://bugs.python.org/issue?@action=redirect&bpo=23782]: Fixed possible memory leak in _PyTraceback_Add() and exception loss in PyTraceBack_Here().

bpo-28471 [https://bugs.python.org/issue?@action=redirect&bpo=28471]: Fix “Python memory allocator called without holding the GIL” crash in socket.setblocking.

Library

bpo-27517 [https://bugs.python.org/issue?@action=redirect&bpo=27517]: LZMA compressor and decompressor no longer raise exceptions if given empty data twice. Patch by Benjamin Fogle.

bpo-28549 [https://bugs.python.org/issue?@action=redirect&bpo=28549]: Fixed segfault in curses’s addch() with ncurses6.

bpo-28449 [https://bugs.python.org/issue?@action=redirect&bpo=28449]: tarfile.open() with mode “r” or “r:” now tries to open a tar file with compression before trying to open it without compression. Otherwise it had 50% chance failed with ignore_zeros=True.

bpo-23262 [https://bugs.python.org/issue?@action=redirect&bpo=23262]: The webbrowser module now supports Firefox 36+ and derived browsers. Based on patch by Oleg Broytman.

bpo-27939 [https://bugs.python.org/issue?@action=redirect&bpo=27939]: Fixed bugs in tkinter.ttk.LabeledScale and tkinter.Scale caused by representing the scale as float value internally in Tk. tkinter.IntVar now works if float value is set to underlying Tk variable.

bpo-18844 [https://bugs.python.org/issue?@action=redirect&bpo=18844]: The various ways of specifying weights for random.choices() now produce the same result sequences.

bpo-28255 [https://bugs.python.org/issue?@action=redirect&bpo=28255]: calendar.TextCalendar().prmonth() no longer prints a space at the start of new line after printing a month’s calendar. Patch by Xiang Zhang.

bpo-20491 [https://bugs.python.org/issue?@action=redirect&bpo=20491]: The textwrap.TextWrapper class now honors non-breaking spaces. Based on patch by Kaarle Ritvanen.

bpo-28353 [https://bugs.python.org/issue?@action=redirect&bpo=28353]: os.fwalk() no longer fails on broken links.

bpo-28430 [https://bugs.python.org/issue?@action=redirect&bpo=28430]: Fix iterator of C implemented asyncio.Future doesn’t accept non-None value is passed to it.send(val).

bpo-27025 [https://bugs.python.org/issue?@action=redirect&bpo=27025]: Generated names for Tkinter widgets now start by the “!” prefix for readability.

bpo-25464 [https://bugs.python.org/issue?@action=redirect&bpo=25464]: Fixed HList.header_exists() in tkinter.tix module by addin a workaround to Tix library bug.

bpo-28488 [https://bugs.python.org/issue?@action=redirect&bpo=28488]: shutil.make_archive() no longer adds entry “./” to ZIP archive.

bpo-25953 [https://bugs.python.org/issue?@action=redirect&bpo=25953]: re.sub() now raises an error for invalid numerical group reference in replacement template even if the pattern is not found in the string. Error message for invalid group reference now includes the group index and the position of the reference. Based on patch by SilentGhost.

bpo-18219 [https://bugs.python.org/issue?@action=redirect&bpo=18219]: Optimize csv.DictWriter for large number of columns. Patch by Mariatta Wijaya.

bpo-28448 [https://bugs.python.org/issue?@action=redirect&bpo=28448]: Fix C implemented asyncio.Future didn’t work on Windows.

bpo-28480 [https://bugs.python.org/issue?@action=redirect&bpo=28480]: Fix error building socket module when multithreading is disabled.

bpo-24452 [https://bugs.python.org/issue?@action=redirect&bpo=24452]: Make webbrowser support Chrome on Mac OS X.

bpo-20766 [https://bugs.python.org/issue?@action=redirect&bpo=20766]: Fix references leaked by pdb in the handling of SIGINT handlers.

bpo-28492 [https://bugs.python.org/issue?@action=redirect&bpo=28492]: Fix how StopIteration exception is raised in _asyncio.Future.

bpo-28500 [https://bugs.python.org/issue?@action=redirect&bpo=28500]: Fix asyncio to handle async gens GC from another thread.

bpo-26923 [https://bugs.python.org/issue?@action=redirect&bpo=26923]: Fix asyncio.Gather to refuse being cancelled once all children are done. Patch by Johannes Ebke.

bpo-26796 [https://bugs.python.org/issue?@action=redirect&bpo=26796]: Don’t configure the number of workers for default threadpool executor. Initial patch by Hans Lawrenz.

bpo-28544 [https://bugs.python.org/issue?@action=redirect&bpo=28544]: Implement asyncio.Task in C.

Windows

bpo-28522 [https://bugs.python.org/issue?@action=redirect&bpo=28522]: Fixes mishandled buffer reallocation in getpathp.c

Build

bpo-28444 [https://bugs.python.org/issue?@action=redirect&bpo=28444]: Fix missing extensions modules when cross compiling.

bpo-28208 [https://bugs.python.org/issue?@action=redirect&bpo=28208]: Update Windows build and OS X installers to use SQLite 3.14.2.

bpo-28248 [https://bugs.python.org/issue?@action=redirect&bpo=28248]: Update Windows build and OS X installers to use OpenSSL 1.0.2j.

Tests

bpo-26944 [https://bugs.python.org/issue?@action=redirect&bpo=26944]: Fix test_posix for Android where ‘id -G’ is entirely wrong or missing the effective gid.

bpo-28409 [https://bugs.python.org/issue?@action=redirect&bpo=28409]: regrtest: fix the parser of command line arguments.

Python 3.6.0 beta 2

Release date: 2016-10-10

Core and Builtins

bpo-28183 [https://bugs.python.org/issue?@action=redirect&bpo=28183]: Optimize and cleanup dict iteration.

bpo-26081 [https://bugs.python.org/issue?@action=redirect&bpo=26081]: Added C implementation of asyncio.Future. Original patch by Yury Selivanov.

bpo-28379 [https://bugs.python.org/issue?@action=redirect&bpo=28379]: Added sanity checks and tests for PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: The type of long range iterator is now registered as Iterator. Patch by Oren Milman.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: Creating instances of range_iterator by calling range_iterator type now is deprecated. Patch by Oren Milman.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: The constructor of range_iterator now checks that step is not 0. Patch by Oren Milman.

bpo-26906 [https://bugs.python.org/issue?@action=redirect&bpo=26906]: Resolving special methods of uninitialized type now causes implicit initialization of the type instead of a fail.

bpo-18287 [https://bugs.python.org/issue?@action=redirect&bpo=18287]: PyType_Ready() now checks that tp_name is not NULL. Original patch by Niklas Koep.

bpo-24098 [https://bugs.python.org/issue?@action=redirect&bpo=24098]: Fixed possible crash when AST is changed in process of compiling it.

bpo-28201 [https://bugs.python.org/issue?@action=redirect&bpo=28201]: Dict reduces possibility of 2nd conflict in hash table when hashes have same lower bits.

bpo-28350 [https://bugs.python.org/issue?@action=redirect&bpo=28350]: String constants with null character no longer interned.

bpo-26617 [https://bugs.python.org/issue?@action=redirect&bpo=26617]: Fix crash when GC runs during weakref callbacks.

bpo-27942 [https://bugs.python.org/issue?@action=redirect&bpo=27942]: String constants now interned recursively in tuples and frozensets.

bpo-21578 [https://bugs.python.org/issue?@action=redirect&bpo=21578]: Fixed misleading error message when ImportError called with invalid keyword args.

bpo-28203 [https://bugs.python.org/issue?@action=redirect&bpo=28203]: Fix incorrect type in complex(1.0, {2:3}) error message. Patch by Soumya Sharma.

bpo-28086 [https://bugs.python.org/issue?@action=redirect&bpo=28086]: Single var-positional argument of tuple subtype was passed unscathed to the C-defined function. Now it is converted to exact tuple.

bpo-28214 [https://bugs.python.org/issue?@action=redirect&bpo=28214]: Now __set_name__ is looked up on the class instead of the instance.

bpo-27955 [https://bugs.python.org/issue?@action=redirect&bpo=27955]: Fallback on reading /dev/urandom device when the getrandom() syscall fails with EPERM, for example when blocked by SECCOMP.

bpo-28192 [https://bugs.python.org/issue?@action=redirect&bpo=28192]: Don’t import readline in isolated mode.

Upgrade internal unicode databases to Unicode version 9.0.0.

bpo-28131 [https://bugs.python.org/issue?@action=redirect&bpo=28131]: Fix a regression in zipimport’s compile_source(). zipimport should use the same optimization level as the interpreter.

bpo-28126 [https://bugs.python.org/issue?@action=redirect&bpo=28126]: Replace Py_MEMCPY with memcpy(). Visual Studio can properly optimize memcpy().

bpo-28120 [https://bugs.python.org/issue?@action=redirect&bpo=28120]: Fix dict.pop() for split dictionary when trying to remove a “pending key” (Not yet inserted in split-table). Patch by Xiang Zhang.

bpo-26182 [https://bugs.python.org/issue?@action=redirect&bpo=26182]: Raise DeprecationWarning when async and await keywords are used as variable/attribute/class/function name.

Library

bpo-27998 [https://bugs.python.org/issue?@action=redirect&bpo=27998]: Fixed bytes path support in os.scandir() on Windows. Patch by Eryk Sun.

bpo-28317 [https://bugs.python.org/issue?@action=redirect&bpo=28317]: The disassembler now decodes FORMAT_VALUE argument.

bpo-26293 [https://bugs.python.org/issue?@action=redirect&bpo=26293]: Fixed writing ZIP files that starts not from the start of the file. Offsets in ZIP file now are relative to the start of the archive in conforming to the specification.

bpo-28380 [https://bugs.python.org/issue?@action=redirect&bpo=28380]: unittest.mock Mock autospec functions now properly support assert_called, assert_not_called, and assert_called_once.

bpo-27181 [https://bugs.python.org/issue?@action=redirect&bpo=27181]: remove statistics.geometric_mean and defer until 3.7.

bpo-28229 [https://bugs.python.org/issue?@action=redirect&bpo=28229]: lzma module now supports pathlib.

bpo-28321 [https://bugs.python.org/issue?@action=redirect&bpo=28321]: Fixed writing non-BMP characters with binary format in plistlib.

bpo-28225 [https://bugs.python.org/issue?@action=redirect&bpo=28225]: bz2 module now supports pathlib. Initial patch by Ethan Furman.

bpo-28227 [https://bugs.python.org/issue?@action=redirect&bpo=28227]: gzip now supports pathlib. Patch by Ethan Furman.

bpo-27358 [https://bugs.python.org/issue?@action=redirect&bpo=27358]: Optimized merging var-keyword arguments and improved error message when passing a non-mapping as a var-keyword argument.

bpo-28257 [https://bugs.python.org/issue?@action=redirect&bpo=28257]: Improved error message when passing a non-iterable as a var-positional argument. Added opcode BUILD_TUPLE_UNPACK_WITH_CALL.

bpo-28322 [https://bugs.python.org/issue?@action=redirect&bpo=28322]: Fixed possible crashes when unpickle itertools objects from incorrect pickle data. Based on patch by John Leitch.

bpo-28228 [https://bugs.python.org/issue?@action=redirect&bpo=28228]: imghdr now supports pathlib.

bpo-28226 [https://bugs.python.org/issue?@action=redirect&bpo=28226]: compileall now supports pathlib.

bpo-28314 [https://bugs.python.org/issue?@action=redirect&bpo=28314]: Fix function declaration (C flags) for the getiterator() method of xml.etree.ElementTree.Element.

bpo-28148 [https://bugs.python.org/issue?@action=redirect&bpo=28148]: Stop using localtime() and gmtime() in the time module. Introduced platform independent _PyTime_localtime API that is similar to POSIX localtime_r, but available on all platforms. Patch by Ed Schouten.

bpo-28253 [https://bugs.python.org/issue?@action=redirect&bpo=28253]: Fixed calendar functions for extreme months: 0001-01 and 9999-12. Methods itermonthdays() and itermonthdays2() are reimplemented so that they don’t call itermonthdates() which can cause datetime.date under/overflow.

bpo-28275 [https://bugs.python.org/issue?@action=redirect&bpo=28275]: Fixed possible use after free in the decompress() methods of the LZMADecompressor and BZ2Decompressor classes. Original patch by John Leitch.

bpo-27897 [https://bugs.python.org/issue?@action=redirect&bpo=27897]: Fixed possible crash in sqlite3.Connection.create_collation() if pass invalid string-like object as a name. Patch by Xiang Zhang.

bpo-18844 [https://bugs.python.org/issue?@action=redirect&bpo=18844]: random.choices() now has k as a keyword-only argument to improve the readability of common cases and come into line with the signature used in other languages.

bpo-18893 [https://bugs.python.org/issue?@action=redirect&bpo=18893]: Fix invalid exception handling in Lib/ctypes/macholib/dyld.py. Patch by Madison May.

bpo-27611 [https://bugs.python.org/issue?@action=redirect&bpo=27611]: Fixed support of default root window in the tkinter.tix module. Added the master parameter in the DisplayStyle constructor.

bpo-27348 [https://bugs.python.org/issue?@action=redirect&bpo=27348]: In the traceback module, restore the formatting of exception messages like “Exception: None”. This fixes a regression introduced in 3.5a2.

bpo-25651 [https://bugs.python.org/issue?@action=redirect&bpo=25651]: Allow false values to be used for msg parameter of subTest().

bpo-27778 [https://bugs.python.org/issue?@action=redirect&bpo=27778]: Fix a memory leak in os.getrandom() when the getrandom() is interrupted by a signal and a signal handler raises a Python exception.

bpo-28200 [https://bugs.python.org/issue?@action=redirect&bpo=28200]: Fix memory leak on Windows in the os module (fix path_converter() function).

bpo-25400 [https://bugs.python.org/issue?@action=redirect&bpo=25400]: RobotFileParser now correctly returns default values for crawl_delay and request_rate. Initial patch by Peter Wirtz.

bpo-27932 [https://bugs.python.org/issue?@action=redirect&bpo=27932]: Prevent memory leak in win32_ver().

Fix UnboundLocalError in socket._sendfile_use_sendfile.

bpo-28075 [https://bugs.python.org/issue?@action=redirect&bpo=28075]: Check for ERROR_ACCESS_DENIED in Windows implementation of os.stat(). Patch by Eryk Sun.

bpo-22493 [https://bugs.python.org/issue?@action=redirect&bpo=22493]: Warning message emitted by using inline flags in the middle of regular expression now contains a (truncated) regex pattern. Patch by Tim Graham.

bpo-25270 [https://bugs.python.org/issue?@action=redirect&bpo=25270]: Prevent codecs.escape_encode() from raising SystemError when an empty bytestring is passed.

bpo-28181 [https://bugs.python.org/issue?@action=redirect&bpo=28181]: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

bpo-25895 [https://bugs.python.org/issue?@action=redirect&bpo=25895]: Enable WebSocket URL schemes in urllib.parse.urljoin. Patch by Gergely Imreh and Markus Holtermann.

bpo-28114 [https://bugs.python.org/issue?@action=redirect&bpo=28114]: Fix a crash in parse_envlist() when env contains byte strings. Patch by Eryk Sun.

bpo-27599 [https://bugs.python.org/issue?@action=redirect&bpo=27599]: Fixed buffer overrun in binascii.b2a_qp() and binascii.a2b_qp().

bpo-27906 [https://bugs.python.org/issue?@action=redirect&bpo=27906]: Fix socket accept exhaustion during high TCP traffic. Patch by Kevin Conway.

bpo-28174 [https://bugs.python.org/issue?@action=redirect&bpo=28174]: Handle when SO_REUSEPORT isn’t properly supported. Patch by Seth Michael Larson.

bpo-26654 [https://bugs.python.org/issue?@action=redirect&bpo=26654]: Inspect functools.partial in asyncio.Handle.__repr__. Patch by iceboy.

bpo-26909 [https://bugs.python.org/issue?@action=redirect&bpo=26909]: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

bpo-28176 [https://bugs.python.org/issue?@action=redirect&bpo=28176]: Fix callbacks race in asyncio.SelectorLoop.sock_connect.

bpo-27759 [https://bugs.python.org/issue?@action=redirect&bpo=27759]: Fix selectors incorrectly retain invalid file descriptors. Patch by Mark Williams.

bpo-28368 [https://bugs.python.org/issue?@action=redirect&bpo=28368]: Refuse monitoring processes if the child watcher has no loop attached. Patch by Vincent Michel.

bpo-28369 [https://bugs.python.org/issue?@action=redirect&bpo=28369]: Raise RuntimeError when transport’s FD is used with add_reader, add_writer, etc.

bpo-28370 [https://bugs.python.org/issue?@action=redirect&bpo=28370]: Speedup asyncio.StreamReader.readexactly. Patch by Коренберг Марк.

bpo-28371 [https://bugs.python.org/issue?@action=redirect&bpo=28371]: Deprecate passing asyncio.Handles to run_in_executor.

bpo-28372 [https://bugs.python.org/issue?@action=redirect&bpo=28372]: Fix asyncio to support formatting of non-python coroutines.

bpo-28399 [https://bugs.python.org/issue?@action=redirect&bpo=28399]: Remove UNIX socket from FS before binding. Patch by Коренберг Марк.

bpo-27972 [https://bugs.python.org/issue?@action=redirect&bpo=27972]: Prohibit Tasks to await on themselves.

Windows

bpo-28402 [https://bugs.python.org/issue?@action=redirect&bpo=28402]: Adds signed catalog files for stdlib on Windows.

bpo-28333 [https://bugs.python.org/issue?@action=redirect&bpo=28333]: Enables Unicode for ps1/ps2 and input() prompts. (Patch by Eryk Sun)

bpo-28251 [https://bugs.python.org/issue?@action=redirect&bpo=28251]: Improvements to help manuals on Windows.

bpo-28110 [https://bugs.python.org/issue?@action=redirect&bpo=28110]: launcher.msi has different product codes between 32-bit and 64-bit

bpo-28161 [https://bugs.python.org/issue?@action=redirect&bpo=28161]: Opening CON for write access fails

bpo-28162 [https://bugs.python.org/issue?@action=redirect&bpo=28162]: WindowsConsoleIO readall() fails if first line starts with Ctrl+Z

bpo-28163 [https://bugs.python.org/issue?@action=redirect&bpo=28163]: WindowsConsoleIO fileno() passes wrong flags to _open_osfhandle

bpo-28164 [https://bugs.python.org/issue?@action=redirect&bpo=28164]: _PyIO_get_console_type fails for various paths

bpo-28137 [https://bugs.python.org/issue?@action=redirect&bpo=28137]: Renames Windows path file to ._pth

bpo-28138 [https://bugs.python.org/issue?@action=redirect&bpo=28138]: Windows ._pth file should allow import site

C API

bpo-28426 [https://bugs.python.org/issue?@action=redirect&bpo=28426]: Deprecated undocumented functions PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(), PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().

Build

bpo-28258 [https://bugs.python.org/issue?@action=redirect&bpo=28258]: Fixed build with Estonian locale (python-config and distclean targets in Makefile). Patch by Arfrever Frehtes Taifersar Arahesis.

bpo-26661 [https://bugs.python.org/issue?@action=redirect&bpo=26661]: setup.py now detects system libffi with multiarch wrapper.

bpo-15819 [https://bugs.python.org/issue?@action=redirect&bpo=15819]: Remove redundant include search directory option for building outside the source tree.

Tests

bpo-28217 [https://bugs.python.org/issue?@action=redirect&bpo=28217]: Adds _testconsole module to test console input.

Python 3.6.0 beta 1

Release date: 2016-09-12

Core and Builtins

bpo-23722 [https://bugs.python.org/issue?@action=redirect&bpo=23722]: The __class__ cell used by zero-argument super() is now initialized from type.__new__ rather than __build_class__, so class methods relying on that will now work correctly when called from metaclass methods during class creation. Patch by Martin Teichmann.

bpo-25221 [https://bugs.python.org/issue?@action=redirect&bpo=25221]: Fix corrupted result from PyLong_FromLong(0) when Python is compiled with NSMALLPOSINTS = 0.

bpo-27080 [https://bugs.python.org/issue?@action=redirect&bpo=27080]: Implement formatting support for PEP 515 [https://peps.python.org/pep-0515/]. Initial patch by Chris Angelico.

bpo-27199 [https://bugs.python.org/issue?@action=redirect&bpo=27199]: In tarfile, expose copyfileobj bufsize to improve throughput. Patch by Jason Fried.

bpo-27948 [https://bugs.python.org/issue?@action=redirect&bpo=27948]: In f-strings, only allow backslashes inside the braces (where the expressions are). This is a breaking change from the 3.6 alpha releases, where backslashes are allowed anywhere in an f-string. Also, require that expressions inside f-strings be enclosed within literal braces, and not escapes like f'\x7b"hi"\x7d'.

bpo-28046 [https://bugs.python.org/issue?@action=redirect&bpo=28046]: Remove platform-specific directories from sys.path.

bpo-28071 [https://bugs.python.org/issue?@action=redirect&bpo=28071]: Add early-out for differencing from an empty set.

bpo-25758 [https://bugs.python.org/issue?@action=redirect&bpo=25758]: Prevents zipimport from unnecessarily encoding a filename (patch by Eryk Sun)

bpo-25856 [https://bugs.python.org/issue?@action=redirect&bpo=25856]: The __module__ attribute of extension classes and functions now is interned. This leads to more compact pickle data with protocol 4.

bpo-27213 [https://bugs.python.org/issue?@action=redirect&bpo=27213]: Rework CALL_FUNCTION* opcodes to produce shorter and more efficient bytecode. Patch by Demur Rumed, design by Serhiy Storchaka, reviewed by Serhiy Storchaka and Victor Stinner.

bpo-26331 [https://bugs.python.org/issue?@action=redirect&bpo=26331]: Implement tokenizing support for PEP 515 [https://peps.python.org/pep-0515/]. Patch by Georg Brandl.

bpo-27999 [https://bugs.python.org/issue?@action=redirect&bpo=27999]: Make “global after use” a SyntaxError, and ditto for nonlocal. Patch by Ivan Levkivskyi.

bpo-28003 [https://bugs.python.org/issue?@action=redirect&bpo=28003]: Implement PEP 525 [https://peps.python.org/pep-0525/] – Asynchronous Generators.

bpo-27985 [https://bugs.python.org/issue?@action=redirect&bpo=27985]: Implement PEP 526 [https://peps.python.org/pep-0526/] – Syntax for Variable Annotations. Patch by Ivan Levkivskyi.

bpo-26058 [https://bugs.python.org/issue?@action=redirect&bpo=26058]: Add a new private version to the builtin dict type, incremented at each dictionary creation and at each dictionary change. Implementation of the PEP 509.

bpo-27364 [https://bugs.python.org/issue?@action=redirect&bpo=27364]: A backslash-character pair that is not a valid escape sequence now generates a DeprecationWarning. Patch by Emanuel Barry.

bpo-27350 [https://bugs.python.org/issue?@action=redirect&bpo=27350]: dict implementation is changed like PyPy. It is more compact and preserves insertion order. (Concept developed by Raymond Hettinger and patch by Inada Naoki.)

bpo-27911 [https://bugs.python.org/issue?@action=redirect&bpo=27911]: Remove unnecessary error checks in exec_builtin_or_dynamic().

bpo-27078 [https://bugs.python.org/issue?@action=redirect&bpo=27078]: Added BUILD_STRING opcode. Optimized f-strings evaluation.

bpo-17884 [https://bugs.python.org/issue?@action=redirect&bpo=17884]: Python now requires systems with inttypes.h and stdint.h

bpo-27961 [https://bugs.python.org/issue?@action=redirect&bpo=27961]: Require platforms to support long long. Python hasn’t compiled without long long for years, so this is basically a formality.

bpo-27355 [https://bugs.python.org/issue?@action=redirect&bpo=27355]: Removed support for Windows CE. It was never finished, and Windows CE is no longer a relevant platform for Python.

Implement PEP 523 [https://peps.python.org/pep-0523/].

bpo-27870 [https://bugs.python.org/issue?@action=redirect&bpo=27870]: A left shift of zero by a large integer no longer attempts to allocate large amounts of memory.

bpo-25402 [https://bugs.python.org/issue?@action=redirect&bpo=25402]: In int-to-decimal-string conversion, improve the estimate of the intermediate memory required, and remove an unnecessarily strict overflow check. Patch by Serhiy Storchaka.

bpo-27214 [https://bugs.python.org/issue?@action=redirect&bpo=27214]: In long_invert, be more careful about modifying object returned by long_add, and remove an unnecessary check for small longs. Thanks Oren Milman for analysis and patch.

bpo-27506 [https://bugs.python.org/issue?@action=redirect&bpo=27506]: Support passing the bytes/bytearray.translate() “delete” argument by keyword.

bpo-27812 [https://bugs.python.org/issue?@action=redirect&bpo=27812]: Properly clear out a generator’s frame’s backreference to the generator to prevent crashes in frame.clear().

bpo-27811 [https://bugs.python.org/issue?@action=redirect&bpo=27811]: Fix a crash when a coroutine that has not been awaited is finalized with warnings-as-errors enabled.

bpo-27587 [https://bugs.python.org/issue?@action=redirect&bpo=27587]: Fix another issue found by PVS-Studio: Null pointer check after use of ‘def’ in _PyState_AddModule(). Initial patch by Christian Heimes.

bpo-27792 [https://bugs.python.org/issue?@action=redirect&bpo=27792]: The modulo operation applied to bool and other int subclasses now always returns an int. Previously the return type depended on the input values. Patch by Xiang Zhang.

bpo-26984 [https://bugs.python.org/issue?@action=redirect&bpo=26984]: int() now always returns an instance of exact int.

bpo-25604 [https://bugs.python.org/issue?@action=redirect&bpo=25604]: Fix a minor bug in integer true division; this bug could potentially have caused off-by-one-ulp results on platforms with unreliable ldexp implementations.

bpo-24254 [https://bugs.python.org/issue?@action=redirect&bpo=24254]: Make class definition namespace ordered by default.

bpo-27662 [https://bugs.python.org/issue?@action=redirect&bpo=27662]: Fix an overflow check in List_New: the original code was checking against Py_SIZE_MAX instead of the correct upper bound of Py_SSIZE_T_MAX. Patch by Xiang Zhang.

bpo-27782 [https://bugs.python.org/issue?@action=redirect&bpo=27782]: Multi-phase extension module import now correctly allows the m_methods field to be used to add module level functions to instances of non-module types returned from Py_create_mod. Patch by Xiang Zhang.

bpo-27936 [https://bugs.python.org/issue?@action=redirect&bpo=27936]: The round() function accepted a second None argument for some types but not for others. Fixed the inconsistency by accepting None for all numeric types.

bpo-27487 [https://bugs.python.org/issue?@action=redirect&bpo=27487]: Warn if a submodule argument to “python -m” or runpy.run_module() is found in sys.modules after parent packages are imported, but before the submodule is executed.

bpo-27157 [https://bugs.python.org/issue?@action=redirect&bpo=27157]: Make only type() itself accept the one-argument form. Patch by Eryk Sun and Emanuel Barry.

bpo-27558 [https://bugs.python.org/issue?@action=redirect&bpo=27558]: Fix a SystemError in the implementation of “raise” statement. In a brand new thread, raise a RuntimeError since there is no active exception to reraise. Patch written by Xiang Zhang.

bpo-28008 [https://bugs.python.org/issue?@action=redirect&bpo=28008]: Implement PEP 530 [https://peps.python.org/pep-0530/] – asynchronous comprehensions.

bpo-27942 [https://bugs.python.org/issue?@action=redirect&bpo=27942]: Fix memory leak in codeobject.c

Library

bpo-28732 [https://bugs.python.org/issue?@action=redirect&bpo=28732]: Fix crash in os.spawnv() with no elements in args

bpo-28485 [https://bugs.python.org/issue?@action=redirect&bpo=28485]: Always raise ValueError for negative compileall.compile_dir(workers=…) parameter, even when multithreading is unavailable.

bpo-28037 [https://bugs.python.org/issue?@action=redirect&bpo=28037]: Use sqlite3_get_autocommit() instead of setting Connection->inTransaction manually.

bpo-25283 [https://bugs.python.org/issue?@action=redirect&bpo=25283]: Attributes tm_gmtoff and tm_zone are now available on all platforms in the return values of time.localtime() and time.gmtime().

bpo-24454 [https://bugs.python.org/issue?@action=redirect&bpo=24454]: Regular expression match object groups are now accessible using __getitem__. “mo[x]” is equivalent to “mo.group(x)”.

bpo-10740 [https://bugs.python.org/issue?@action=redirect&bpo=10740]: sqlite3 no longer implicitly commit an open transaction before DDL statements.

bpo-17941 [https://bugs.python.org/issue?@action=redirect&bpo=17941]: Add a module parameter to collections.namedtuple().

bpo-22493 [https://bugs.python.org/issue?@action=redirect&bpo=22493]: Inline flags now should be used only at the start of the regular expression. Deprecation warning is emitted if uses them in the middle of the regular expression.

bpo-26885 [https://bugs.python.org/issue?@action=redirect&bpo=26885]: xmlrpc now supports unmarshalling additional data types used by Apache XML-RPC implementation for numerics and None.

bpo-28070 [https://bugs.python.org/issue?@action=redirect&bpo=28070]: Fixed parsing inline verbose flag in regular expressions.

bpo-19500 [https://bugs.python.org/issue?@action=redirect&bpo=19500]: Add client-side SSL session resumption to the ssl module.

bpo-28022 [https://bugs.python.org/issue?@action=redirect&bpo=28022]: Deprecate ssl-related arguments in favor of SSLContext. The deprecation include manual creation of SSLSocket and certfile/keyfile (or similar) in ftplib, httplib, imaplib, smtplib, poplib and urllib.

bpo-28043 [https://bugs.python.org/issue?@action=redirect&bpo=28043]: SSLContext has improved default settings: OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION, OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE and HIGH ciphers without MD5.

bpo-24693 [https://bugs.python.org/issue?@action=redirect&bpo=24693]: Changed some RuntimeError’s in the zipfile module to more appropriate types. Improved some error messages and debugging output.

bpo-17909 [https://bugs.python.org/issue?@action=redirect&bpo=17909]: json.load and json.loads now support binary input encoded as UTF-8, UTF-16 or UTF-32. Patch by Serhiy Storchaka.

bpo-27137 [https://bugs.python.org/issue?@action=redirect&bpo=27137]: the pure Python fallback implementation of functools.partial now matches the behaviour of its accelerated C counterpart for subclassing, pickling and text representation purposes. Patch by Emanuel Barry and Serhiy Storchaka.

Fix possible integer overflows and crashes in the mmap module with unusual usage patterns.

bpo-1703178 [https://bugs.python.org/issue?@action=redirect&bpo=1703178]: Fix the ability to pass the –link-objects option to the distutils build_ext command.

bpo-28019 [https://bugs.python.org/issue?@action=redirect&bpo=28019]: itertools.count() no longer rounds non-integer step in range between 1.0 and 2.0 to 1.

bpo-18401 [https://bugs.python.org/issue?@action=redirect&bpo=18401]: Pdb now supports the ‘readrc’ keyword argument to control whether .pdbrc files should be read. Patch by Martin Matusiak and Sam Kimbrel.

bpo-25969 [https://bugs.python.org/issue?@action=redirect&bpo=25969]: Update the lib2to3 grammar to handle the unpacking generalizations added in 3.5.

bpo-14977 [https://bugs.python.org/issue?@action=redirect&bpo=14977]: mailcap now respects the order of the lines in the mailcap files (“first match”), as required by RFC 1542. Patch by Michael Lazar.

bpo-28082 [https://bugs.python.org/issue?@action=redirect&bpo=28082]: Convert re flag constants to IntFlag.

bpo-28025 [https://bugs.python.org/issue?@action=redirect&bpo=28025]: Convert all ssl module constants to IntEnum and IntFlags. SSLContext properties now return flags and enums.

bpo-23591 [https://bugs.python.org/issue?@action=redirect&bpo=23591]: Add Flag, IntFlag, and auto() to enum module.

bpo-433028 [https://bugs.python.org/issue?@action=redirect&bpo=433028]: Added support of modifier spans in regular expressions.

bpo-24594 [https://bugs.python.org/issue?@action=redirect&bpo=24594]: Validates persist parameter when opening MSI database

bpo-17582 [https://bugs.python.org/issue?@action=redirect&bpo=17582]: xml.etree.ElementTree nows preserves whitespaces in attributes (Patch by Duane Griffin. Reviewed and approved by Stefan Behnel.)

bpo-28047 [https://bugs.python.org/issue?@action=redirect&bpo=28047]: Fixed calculation of line length used for the base64 CTE in the new email policies.

bpo-27576 [https://bugs.python.org/issue?@action=redirect&bpo=27576]: Fix call order in OrderedDict.__init__().

email.generator.DecodedGenerator now supports the policy keyword.

bpo-28027 [https://bugs.python.org/issue?@action=redirect&bpo=28027]: Remove undocumented modules from Lib/plat-*: IN, CDROM, DLFCN, TYPES, CDIO, and STROPTS.

bpo-27445 [https://bugs.python.org/issue?@action=redirect&bpo=27445]: Don’t pass str(_charset) to MIMEText.set_payload(). Patch by Claude Paroz.

bpo-24277 [https://bugs.python.org/issue?@action=redirect&bpo=24277]: The new email API is no longer provisional, and the docs have been reorganized and rewritten to emphasize the new API.

bpo-22450 [https://bugs.python.org/issue?@action=redirect&bpo=22450]: urllib now includes an Accept: */* header among the default headers. This makes the results of REST API requests more consistent and predictable especially when proxy servers are involved.

lib2to3.pgen3.driver.load_grammar() now creates a stable cache file between runs given the same Grammar.txt input regardless of the hash randomization setting.

bpo-28005 [https://bugs.python.org/issue?@action=redirect&bpo=28005]: Allow ImportErrors in encoding implementation to propagate.

bpo-26667 [https://bugs.python.org/issue?@action=redirect&bpo=26667]: Support path-like objects in importlib.util.

bpo-27570 [https://bugs.python.org/issue?@action=redirect&bpo=27570]: Avoid zero-length memcpy() etc calls with null source pointers in the “ctypes” and “array” modules.

bpo-22233 [https://bugs.python.org/issue?@action=redirect&bpo=22233]: Break email header lines only on the RFC specified CR and LF characters, not on arbitrary unicode line breaks. This also fixes a bug in HTTP header parsing.

bpo-27331 [https://bugs.python.org/issue?@action=redirect&bpo=27331]: The email.mime classes now all accept an optional policy keyword.

bpo-27988 [https://bugs.python.org/issue?@action=redirect&bpo=27988]: Fix email iter_attachments incorrect mutation of payload list.

bpo-16113 [https://bugs.python.org/issue?@action=redirect&bpo=16113]: Add SHA-3 and SHAKE support to hashlib module.

Eliminate a tautological-pointer-compare warning in _scproxy.c.

bpo-27776 [https://bugs.python.org/issue?@action=redirect&bpo=27776]: The os.urandom() function does now block on Linux 3.17 and newer until the system urandom entropy pool is initialized to increase the security. This change is part of the PEP 524 [https://peps.python.org/pep-0524/].

bpo-27778 [https://bugs.python.org/issue?@action=redirect&bpo=27778]: Expose the Linux getrandom() syscall as a new os.getrandom() function. This change is part of the PEP 524 [https://peps.python.org/pep-0524/].

bpo-27691 [https://bugs.python.org/issue?@action=redirect&bpo=27691]: Fix ssl module’s parsing of GEN_RID subject alternative name fields in X.509 certs.

bpo-18844 [https://bugs.python.org/issue?@action=redirect&bpo=18844]: Add random.choices().

bpo-25761 [https://bugs.python.org/issue?@action=redirect&bpo=25761]: Improved error reporting about truncated pickle data in C implementation of unpickler. UnpicklingError is now raised instead of AttributeError and ValueError in some cases.

bpo-26798 [https://bugs.python.org/issue?@action=redirect&bpo=26798]: Add BLAKE2 (blake2b and blake2s) to hashlib.

bpo-26032 [https://bugs.python.org/issue?@action=redirect&bpo=26032]: Optimized globbing in pathlib by using os.scandir(); it is now about 1.5–4 times faster.

bpo-25596 [https://bugs.python.org/issue?@action=redirect&bpo=25596]: Optimized glob() and iglob() functions in the glob module; they are now about 3–6 times faster.

bpo-27928 [https://bugs.python.org/issue?@action=redirect&bpo=27928]: Add scrypt (password-based key derivation function) to hashlib module (requires OpenSSL 1.1.0).

bpo-27850 [https://bugs.python.org/issue?@action=redirect&bpo=27850]: Remove 3DES from ssl module’s default cipher list to counter measure sweet32 attack (CVE 2016-2183 [https://www.cve.org/CVERecord?id=CVE-2016-2183]).

bpo-27766 [https://bugs.python.org/issue?@action=redirect&bpo=27766]: Add ChaCha20 Poly1305 to ssl module’s default cipher list. (Required OpenSSL 1.1.0 or LibreSSL).

bpo-25387 [https://bugs.python.org/issue?@action=redirect&bpo=25387]: Check return value of winsound.MessageBeep.

bpo-27866 [https://bugs.python.org/issue?@action=redirect&bpo=27866]: Add SSLContext.get_ciphers() method to get a list of all enabled ciphers.

bpo-27744 [https://bugs.python.org/issue?@action=redirect&bpo=27744]: Add AF_ALG (Linux Kernel crypto) to socket module.

bpo-26470 [https://bugs.python.org/issue?@action=redirect&bpo=26470]: Port ssl and hashlib module to OpenSSL 1.1.0.

bpo-11620 [https://bugs.python.org/issue?@action=redirect&bpo=11620]: Fix support for SND_MEMORY in winsound.PlaySound. Based on a patch by Tim Lesher.

bpo-11734 [https://bugs.python.org/issue?@action=redirect&bpo=11734]: Add support for IEEE 754 half-precision floats to the struct module. Based on a patch by Eli Stevens.

bpo-27919 [https://bugs.python.org/issue?@action=redirect&bpo=27919]: Deprecated extra_path distribution option in distutils packaging.

bpo-23229 [https://bugs.python.org/issue?@action=redirect&bpo=23229]: Add new cmath constants: cmath.inf and cmath.nan to match math.inf and math.nan, and also cmath.infj and cmath.nanj to match the format used by complex repr.

bpo-27842 [https://bugs.python.org/issue?@action=redirect&bpo=27842]: The csv.DictReader now returns rows of type OrderedDict. (Contributed by Steve Holden.)

Remove support for passing a file descriptor to os.access. It never worked but previously didn’t raise.

bpo-12885 [https://bugs.python.org/issue?@action=redirect&bpo=12885]: Fix error when distutils encounters symlink.

bpo-27881 [https://bugs.python.org/issue?@action=redirect&bpo=27881]: Fixed possible bugs when setting sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

bpo-27861 [https://bugs.python.org/issue?@action=redirect&bpo=27861]: Fixed a crash in sqlite3.Connection.cursor() when a factory creates not a cursor. Patch by Xiang Zhang.

bpo-19884 [https://bugs.python.org/issue?@action=redirect&bpo=19884]: Avoid spurious output on OS X with Gnu Readline.

bpo-27706 [https://bugs.python.org/issue?@action=redirect&bpo=27706]: Restore deterministic behavior of random.Random().seed() for string seeds using seeding version 1. Allows sequences of calls to random() to exactly match those obtained in Python 2. Patch by Nofar Schnider.

bpo-10513 [https://bugs.python.org/issue?@action=redirect&bpo=10513]: Fix a regression in Connection.commit(). Statements should not be reset after a commit.

bpo-12319 [https://bugs.python.org/issue?@action=redirect&bpo=12319]: Chunked transfer encoding support added to http.client.HTTPConnection requests. The urllib.request.AbstractHTTPHandler class does not enforce a Content-Length header any more. If a HTTP request has a file or iterable body, but no Content-Length header, the library now falls back to use chunked transfer-encoding.

A new version of typing.py from https://github.com/python/typing: - Collection (only for 3.6) (bpo-27598 [https://bugs.python.org/issue?@action=redirect&bpo=27598]) - Add FrozenSet to __all__ (upstream #261) - fix crash in _get_type_vars() (upstream #259) - Remove the dict constraint in ForwardRef._eval_type (upstream #252)

bpo-27832 [https://bugs.python.org/issue?@action=redirect&bpo=27832]: Make _normalize parameter to Fraction constructor keyword-only, so that Fraction(2, 3, 4) now raises TypeError.

bpo-27539 [https://bugs.python.org/issue?@action=redirect&bpo=27539]: Fix unnormalised Fraction.__pow__ result in the case of negative exponent and negative base.

bpo-21718 [https://bugs.python.org/issue?@action=redirect&bpo=21718]: cursor.description is now available for queries using CTEs.

bpo-27819 [https://bugs.python.org/issue?@action=redirect&bpo=27819]: In distutils sdists, simply produce the “gztar” (gzipped tar format) distributions on all platforms unless “formats” is supplied.

bpo-2466 [https://bugs.python.org/issue?@action=redirect&bpo=2466]: posixpath.ismount now correctly recognizes mount points which the user does not have permission to access.

bpo-9998 [https://bugs.python.org/issue?@action=redirect&bpo=9998]: On Linux, ctypes.util.find_library now looks in LD_LIBRARY_PATH for shared libraries.

bpo-27573 [https://bugs.python.org/issue?@action=redirect&bpo=27573]: exit message for code.interact is now configurable.

bpo-27930 [https://bugs.python.org/issue?@action=redirect&bpo=27930]: Improved behaviour of logging.handlers.QueueListener. Thanks to Paulo Andrade and Petr Viktorin for the analysis and patch.

bpo-6766 [https://bugs.python.org/issue?@action=redirect&bpo=6766]: Distributed reference counting added to multiprocessing to support nesting of shared values / proxy objects.

bpo-21201 [https://bugs.python.org/issue?@action=redirect&bpo=21201]: Improves readability of multiprocessing error message. Thanks to Wojciech Walczak for patch.

asyncio: Add set_protocol / get_protocol to Transports.

bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456]: asyncio: Set TCP_NODELAY by default.

IDLE

bpo-15308 [https://bugs.python.org/issue?@action=redirect&bpo=15308]: Add ‘interrupt execution’ (^C) to Shell menu. Patch by Roger Serwy, updated by Bayard Randel.

bpo-27922 [https://bugs.python.org/issue?@action=redirect&bpo=27922]: Stop IDLE tests from ‘flashing’ gui widgets on the screen.

bpo-27891 [https://bugs.python.org/issue?@action=redirect&bpo=27891]: Consistently group and sort imports within idlelib modules.

bpo-17642 [https://bugs.python.org/issue?@action=redirect&bpo=17642]: add larger font sizes for classroom projection.

Add version to title of IDLE help window.

bpo-25564 [https://bugs.python.org/issue?@action=redirect&bpo=25564]: In section on IDLE – console differences, mention that using exec means that __builtins__ is defined for each statement.

bpo-27821 [https://bugs.python.org/issue?@action=redirect&bpo=27821]: Fix 3.6.0a3 regression that prevented custom key sets from being selected when no custom theme was defined.

C API

bpo-26900 [https://bugs.python.org/issue?@action=redirect&bpo=26900]: Excluded underscored names and other private API from limited API.

bpo-26027 [https://bugs.python.org/issue?@action=redirect&bpo=26027]: Add support for path-like objects in PyUnicode_FSConverter() & PyUnicode_FSDecoder().

Tests

bpo-27427 [https://bugs.python.org/issue?@action=redirect&bpo=27427]: Additional tests for the math module. Patch by Francisco Couzo.

bpo-27953 [https://bugs.python.org/issue?@action=redirect&bpo=27953]: Skip math and cmath tests that fail on OS X 10.4 due to a poor libm implementation of tan.

bpo-26040 [https://bugs.python.org/issue?@action=redirect&bpo=26040]: Improve test_math and test_cmath coverage and rigour. Patch by Jeff Allen.

bpo-27787 [https://bugs.python.org/issue?@action=redirect&bpo=27787]: Call gc.collect() before checking each test for “dangling threads”, since the dangling threads are weak references.

Build

bpo-27566 [https://bugs.python.org/issue?@action=redirect&bpo=27566]: Fix clean target in freeze makefile (patch by Lisa Roach)

bpo-27705 [https://bugs.python.org/issue?@action=redirect&bpo=27705]: Update message in validate_ucrtbase.py

bpo-27976 [https://bugs.python.org/issue?@action=redirect&bpo=27976]: Deprecate building _ctypes with the bundled copy of libffi on non-OSX UNIX platforms.

bpo-27983 [https://bugs.python.org/issue?@action=redirect&bpo=27983]: Cause lack of llvm-profdata tool when using clang as required for PGO linking to be a configure time error rather than make time when --with-optimizations is enabled. Also improve our ability to find the llvm-profdata tool on MacOS and some Linuxes.

bpo-21590 [https://bugs.python.org/issue?@action=redirect&bpo=21590]: Support for DTrace and SystemTap probes.

bpo-26307 [https://bugs.python.org/issue?@action=redirect&bpo=26307]: The profile-opt build now applies PGO to the built-in modules.

bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359]: Add the –with-optimizations flag to turn on LTO and PGO build support when available.

bpo-27917 [https://bugs.python.org/issue?@action=redirect&bpo=27917]: Set platform triplets for Android builds.

bpo-25825 [https://bugs.python.org/issue?@action=redirect&bpo=25825]: Update references to the $(LIBPL) installation path on AIX. This path was changed in 3.2a4.

Update OS X installer to use SQLite 3.14.1 and XZ 5.2.2.

bpo-21122 [https://bugs.python.org/issue?@action=redirect&bpo=21122]: Fix LTO builds on OS X.

bpo-17128 [https://bugs.python.org/issue?@action=redirect&bpo=17128]: Build OS X installer with a private copy of OpenSSL. Also provide a sample Install Certificates command script to install a set of root certificates from the third-party certifi module.

Tools/Demos

bpo-27952 [https://bugs.python.org/issue?@action=redirect&bpo=27952]: Get Tools/scripts/fixcid.py working with Python 3 and the current “re” module, avoid invalid Python backslash escapes, and fix a bug parsing escaped C quote signs.

Windows

bpo-28065 [https://bugs.python.org/issue?@action=redirect&bpo=28065]: Update xz dependency to 5.2.2 and build it from source.

bpo-25144 [https://bugs.python.org/issue?@action=redirect&bpo=25144]: Ensures TargetDir is set before continuing with custom install.

bpo-1602 [https://bugs.python.org/issue?@action=redirect&bpo=1602]: Windows console doesn’t input or print Unicode (PEP 528)

bpo-27781 [https://bugs.python.org/issue?@action=redirect&bpo=27781]: Change file system encoding on Windows to UTF-8 (PEP 529)

bpo-27731 [https://bugs.python.org/issue?@action=redirect&bpo=27731]: Opt-out of MAX_PATH on Windows 10

bpo-6135 [https://bugs.python.org/issue?@action=redirect&bpo=6135]: Adds encoding and errors parameters to subprocess.

bpo-27959 [https://bugs.python.org/issue?@action=redirect&bpo=27959]: Adds oem encoding, alias ansi to mbcs, move aliasmbcs to codec lookup.

bpo-27982 [https://bugs.python.org/issue?@action=redirect&bpo=27982]: The functions of the winsound module now accept keyword arguments.

bpo-20366 [https://bugs.python.org/issue?@action=redirect&bpo=20366]: Build full text search support into SQLite on Windows.

bpo-27756 [https://bugs.python.org/issue?@action=redirect&bpo=27756]: Adds new icons for Python files and processes on Windows. Designs by Cherry Wang.

bpo-27883 [https://bugs.python.org/issue?@action=redirect&bpo=27883]: Update sqlite to 3.14.1.0 on Windows.

Python 3.6.0 alpha 4

Release date: 2016-08-15

Core and Builtins

bpo-27704 [https://bugs.python.org/issue?@action=redirect&bpo=27704]: Optimized creating bytes and bytearray from byte-like objects and iterables. Speed up to 3 times for short objects. Original patch by Naoki Inada.

bpo-26823 [https://bugs.python.org/issue?@action=redirect&bpo=26823]: Large sections of repeated lines in tracebacks are now abbreviated as “[Previous line repeated {count} more times]” by the builtin traceback rendering. Patch by Emanuel Barry.

bpo-27574 [https://bugs.python.org/issue?@action=redirect&bpo=27574]: Decreased an overhead of parsing keyword arguments in functions implemented with using Argument Clinic.

bpo-22557 [https://bugs.python.org/issue?@action=redirect&bpo=22557]: Now importing already imported modules is up to 2.5 times faster.

bpo-17596 [https://bugs.python.org/issue?@action=redirect&bpo=17596]: Include <wincrypt.h> to help with Min GW building.

bpo-17599 [https://bugs.python.org/issue?@action=redirect&bpo=17599]: On Windows, rename the privately defined REPARSE_DATA_BUFFER structure to avoid conflicting with the definition from Min GW.

bpo-27507 [https://bugs.python.org/issue?@action=redirect&bpo=27507]: Add integer overflow check in bytearray.extend(). Patch by Xiang Zhang.

bpo-27581 [https://bugs.python.org/issue?@action=redirect&bpo=27581]: Don’t rely on wrapping for overflow check in PySequence_Tuple(). Patch by Xiang Zhang.

bpo-1621 [https://bugs.python.org/issue?@action=redirect&bpo=1621]: Avoid signed integer overflow in list and tuple operations. Patch by Xiang Zhang.

bpo-27419 [https://bugs.python.org/issue?@action=redirect&bpo=27419]: Standard __import__() no longer look up “__import__” in globals or builtins for importing submodules or “from import”. Fixed a crash if raise a warning about unabling to resolve package from __spec__ or __package__.

bpo-27083 [https://bugs.python.org/issue?@action=redirect&bpo=27083]: Respect the PYTHONCASEOK environment variable under Windows.

bpo-27514 [https://bugs.python.org/issue?@action=redirect&bpo=27514]: Make having too many statically nested blocks a SyntaxError instead of SystemError.

bpo-27366 [https://bugs.python.org/issue?@action=redirect&bpo=27366]: Implemented PEP 487 [https://peps.python.org/pep-0487/] (Simpler customization of class creation). Upon subclassing, the __init_subclass__ classmethod is called on the base class. Descriptors are initialized with __set_name__ after class creation.

Library

bpo-26027 [https://bugs.python.org/issue?@action=redirect&bpo=26027]: Add PEP 519 [https://peps.python.org/pep-0519/]/__fspath__() support to the os and os.path modules. Includes code from Jelle Zijlstra. (See also: bpo-27524 [https://bugs.python.org/issue?@action=redirect&bpo=27524])

bpo-27598 [https://bugs.python.org/issue?@action=redirect&bpo=27598]: Add Collections to collections.abc. Patch by Ivan Levkivskyi, docs by Neil Girdhar.

bpo-25958 [https://bugs.python.org/issue?@action=redirect&bpo=25958]: Support “anti-registration” of special methods from various ABCs, like __hash__, __iter__ or __len__. All these (and several more) can be set to None in an implementation class and the behavior will be as if the method is not defined at all. (Previously, this mechanism existed only for __hash__, to make mutable classes unhashable.) Code contributed by Andrew Barnert and Ivan Levkivskyi.

bpo-16764 [https://bugs.python.org/issue?@action=redirect&bpo=16764]: Support keyword arguments to zlib.decompress(). Patch by Xiang Zhang.

bpo-27736 [https://bugs.python.org/issue?@action=redirect&bpo=27736]: Prevent segfault after interpreter re-initialization due to ref count problem introduced in code for bpo-27038 [https://bugs.python.org/issue?@action=redirect&bpo=27038] in 3.6.0a3. Patch by Xiang Zhang.

bpo-25628 [https://bugs.python.org/issue?@action=redirect&bpo=25628]: The verbose and rename parameters for collections.namedtuple are now keyword-only.

bpo-12345 [https://bugs.python.org/issue?@action=redirect&bpo=12345]: Add mathematical constant tau to math and cmath. See also PEP 628 [https://peps.python.org/pep-0628/].

bpo-26823 [https://bugs.python.org/issue?@action=redirect&bpo=26823]: traceback.StackSummary.format now abbreviates large sections of repeated lines as “[Previous line repeated {count} more times]” (this change then further affects other traceback display operations in the module). Patch by Emanuel Barry.

bpo-27664 [https://bugs.python.org/issue?@action=redirect&bpo=27664]: Add to concurrent.futures.thread.ThreadPoolExecutor() the ability to specify a thread name prefix.

bpo-27181 [https://bugs.python.org/issue?@action=redirect&bpo=27181]: Add geometric_mean and harmonic_mean to statistics module.

bpo-27573 [https://bugs.python.org/issue?@action=redirect&bpo=27573]: code.interact now prints an message when exiting.

bpo-6422 [https://bugs.python.org/issue?@action=redirect&bpo=6422]: Add autorange method to timeit.Timer objects.

bpo-27773 [https://bugs.python.org/issue?@action=redirect&bpo=27773]: Correct some memory management errors server_hostname in _ssl.wrap_socket().

bpo-26750 [https://bugs.python.org/issue?@action=redirect&bpo=26750]: unittest.mock.create_autospec() now works properly for subclasses of property() and other data descriptors. Removes the never publicly used, never documented unittest.mock.DescriptorTypes tuple.

bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754]: Undocumented support of general bytes-like objects as path in compile() and similar functions is now deprecated.

bpo-26800 [https://bugs.python.org/issue?@action=redirect&bpo=26800]: Undocumented support of general bytes-like objects as paths in os functions is now deprecated.

bpo-26981 [https://bugs.python.org/issue?@action=redirect&bpo=26981]: Add _order_ compatibility shim to enum.Enum for Python 2/3 code bases.

bpo-27661 [https://bugs.python.org/issue?@action=redirect&bpo=27661]: Added tzinfo keyword argument to datetime.combine.

In the curses module, raise an error if window.getstr() or window.instr() is passed a negative value.

bpo-27783 [https://bugs.python.org/issue?@action=redirect&bpo=27783]: Fix possible usage of uninitialized memory in operator.methodcaller.

bpo-27774 [https://bugs.python.org/issue?@action=redirect&bpo=27774]: Fix possible Py_DECREF on unowned object in _sre.

bpo-27760 [https://bugs.python.org/issue?@action=redirect&bpo=27760]: Fix possible integer overflow in binascii.b2a_qp.

bpo-27758 [https://bugs.python.org/issue?@action=redirect&bpo=27758]: Fix possible integer overflow in the _csv module for large record lengths.

bpo-27568 [https://bugs.python.org/issue?@action=redirect&bpo=27568]: Prevent HTTPoxy attack (CVE 2016-1000110 [https://www.cve.org/CVERecord?id=CVE-2016-1000110]). Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is set, which indicates that the script is in CGI mode.

bpo-7063 [https://bugs.python.org/issue?@action=redirect&bpo=7063]: Remove dead code from the “array” module’s slice handling. Patch by Chuck.

bpo-27656 [https://bugs.python.org/issue?@action=redirect&bpo=27656]: Do not assume sched.h defines any SCHED_* constants.

bpo-27130 [https://bugs.python.org/issue?@action=redirect&bpo=27130]: In the “zlib” module, fix handling of large buffers (typically 4 GiB) when compressing and decompressing. Previously, inputs were limited to 4 GiB, and compression and decompression operations did not properly handle results of 4 GiB.

bpo-24773 [https://bugs.python.org/issue?@action=redirect&bpo=24773]: Implemented PEP 495 [https://peps.python.org/pep-0495/] (Local Time Disambiguation).

Expose the EPOLLEXCLUSIVE constant (when it is defined) in the select module.

bpo-27567 [https://bugs.python.org/issue?@action=redirect&bpo=27567]: Expose the EPOLLRDHUP and POLLRDHUP constants in the select module.

bpo-1621 [https://bugs.python.org/issue?@action=redirect&bpo=1621]: Avoid signed int negation overflow in the “audioop” module.

bpo-27533 [https://bugs.python.org/issue?@action=redirect&bpo=27533]: Release GIL in nt._isdir

bpo-17711 [https://bugs.python.org/issue?@action=redirect&bpo=17711]: Fixed unpickling by the persistent ID with protocol 0. Original patch by Alexandre Vassalotti.

bpo-27522 [https://bugs.python.org/issue?@action=redirect&bpo=27522]: Avoid an unintentional reference cycle in email.feedparser.

bpo-27512 [https://bugs.python.org/issue?@action=redirect&bpo=27512]: Fix a segfault when os.fspath() called an __fspath__() method that raised an exception. Patch by Xiang Zhang.

IDLE

bpo-27714 [https://bugs.python.org/issue?@action=redirect&bpo=27714]: text_textview and test_autocomplete now pass when re-run in the same process. This occurs when test_idle fails when run with the -w option but without -jn. Fix warning from test_config.

bpo-27621 [https://bugs.python.org/issue?@action=redirect&bpo=27621]: Put query response validation error messages in the query box itself instead of in a separate messagebox. Redo tests to match. Add Mac OSX refinements. Original patch by Mark Roseman.

bpo-27620 [https://bugs.python.org/issue?@action=redirect&bpo=27620]: Escape key now closes Query box as cancelled.

bpo-27609 [https://bugs.python.org/issue?@action=redirect&bpo=27609]: IDLE: tab after initial whitespace should tab, not autocomplete. This fixes problem with writing docstrings at least twice indented.

bpo-27609 [https://bugs.python.org/issue?@action=redirect&bpo=27609]: Explicitly return None when there are also non-None returns. In a few cases, reverse a condition and eliminate a return.

bpo-25507 [https://bugs.python.org/issue?@action=redirect&bpo=25507]: IDLE no longer runs buggy code because of its tkinter imports. Users must include the same imports required to run directly in Python.

bpo-27173 [https://bugs.python.org/issue?@action=redirect&bpo=27173]: Add ‘IDLE Modern Unix’ to the built-in key sets. Make the default key set depend on the platform. Add tests for the changes to the config module.

bpo-27452 [https://bugs.python.org/issue?@action=redirect&bpo=27452]: add line counter and crc to IDLE configHandler test dump.

Tests

bpo-25805 [https://bugs.python.org/issue?@action=redirect&bpo=25805]: Skip a test in test_pkgutil as needed that doesn’t work when __name__ == __main__. Patch by SilentGhost.

bpo-27472 [https://bugs.python.org/issue?@action=redirect&bpo=27472]: Add test.support.unix_shell as the path to the default shell.

bpo-27369 [https://bugs.python.org/issue?@action=redirect&bpo=27369]: In test_pyexpat, avoid testing an error message detail that changed in Expat 2.2.0.

bpo-27594 [https://bugs.python.org/issue?@action=redirect&bpo=27594]: Prevent assertion error when running test_ast with coverage enabled: ensure code object has a valid first line number. Patch suggested by Ivan Levkivskyi.

Windows

bpo-27647 [https://bugs.python.org/issue?@action=redirect&bpo=27647]: Update bundled Tcl/Tk to 8.6.6.

bpo-27610 [https://bugs.python.org/issue?@action=redirect&bpo=27610]: Adds PEP 514 [https://peps.python.org/pep-0514/] metadata to Windows installer

bpo-27469 [https://bugs.python.org/issue?@action=redirect&bpo=27469]: Adds a shell extension to the launcher so that drag and drop works correctly.

bpo-27309 [https://bugs.python.org/issue?@action=redirect&bpo=27309]: Enables proper Windows styles in python[w].exe manifest.

Build

bpo-27713 [https://bugs.python.org/issue?@action=redirect&bpo=27713]: Suppress spurious build warnings when updating importlib’s bootstrap files. Patch by Xiang Zhang

bpo-25825 [https://bugs.python.org/issue?@action=redirect&bpo=25825]: Correct the references to Modules/python.exp, which is required on AIX. The references were accidentally changed in 3.5.0a1.

bpo-27453 [https://bugs.python.org/issue?@action=redirect&bpo=27453]: CPP invocation in configure must use CPPFLAGS. Patch by Chi Hsuan Yen.

bpo-27641 [https://bugs.python.org/issue?@action=redirect&bpo=27641]: The configure script now inserts comments into the makefile to prevent the pgen and _freeze_importlib executables from being cross-compiled.

bpo-26662 [https://bugs.python.org/issue?@action=redirect&bpo=26662]: Set PYTHON_FOR_GEN in configure as the Python program to be used for file generation during the build.

bpo-10910 [https://bugs.python.org/issue?@action=redirect&bpo=10910]: Avoid C++ compilation errors on FreeBSD and OS X. Also update FreedBSD version checks for the original ctype UTF-8 workaround.

Python 3.6.0 alpha 3

Release date: 2016-07-11

Security

bpo-27278 [https://bugs.python.org/issue?@action=redirect&bpo=27278]: Fix os.urandom() implementation using getrandom() on Linux. Truncate size to INT_MAX and loop until we collected enough random bytes, instead of casting a directly Py_ssize_t to int.

bpo-22636 [https://bugs.python.org/issue?@action=redirect&bpo=22636]: Avoid shell injection problems with ctypes.util.find_library().

Core and Builtins

bpo-27473 [https://bugs.python.org/issue?@action=redirect&bpo=27473]: Fixed possible integer overflow in bytes and bytearray concatenations. Patch by Xiang Zhang.

bpo-23034 [https://bugs.python.org/issue?@action=redirect&bpo=23034]: The output of a special Python build with defined COUNT_ALLOCS, SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off by default. It can be re-enabled using the “-X showalloccount” option. It now outputs to stderr instead of stdout.

bpo-27443 [https://bugs.python.org/issue?@action=redirect&bpo=27443]: __length_hint__() of bytearray iterators no longer return a negative integer for a resized bytearray.

bpo-27007 [https://bugs.python.org/issue?@action=redirect&bpo=27007]: The fromhex() class methods of bytes and bytearray subclasses now return an instance of corresponding subclass.

Library

bpo-26844 [https://bugs.python.org/issue?@action=redirect&bpo=26844]: Fix error message for imp.find_module() to refer to ‘path’ instead of ‘name’. Patch by Lev Maximov.

bpo-23804 [https://bugs.python.org/issue?@action=redirect&bpo=23804]: Fix SSL zero-length recv() calls to not block and not raise an error about unclean EOF.

bpo-27466 [https://bugs.python.org/issue?@action=redirect&bpo=27466]: Change time format returned by http.cookie.time2netscape, confirming the netscape cookie format and making it consistent with documentation.

bpo-21708 [https://bugs.python.org/issue?@action=redirect&bpo=21708]: Deprecated dbm.dumb behavior that differs from common dbm behavior: creating a database in ‘r’ and ‘w’ modes and modifying a database in ‘r’ mode.

bpo-26721 [https://bugs.python.org/issue?@action=redirect&bpo=26721]: Change the socketserver.StreamRequestHandler.wfile attribute to implement BufferedIOBase. In particular, the write() method no longer does partial writes.

bpo-22115 [https://bugs.python.org/issue?@action=redirect&bpo=22115]: Added methods trace_add, trace_remove and trace_info in the tkinter.Variable class. They replace old methods trace_variable, trace, trace_vdelete and trace_vinfo that use obsolete Tcl commands and might not work in future versions of Tcl. Fixed old tracing methods: trace_vdelete() with wrong mode no longer break tracing, trace_vinfo() now always returns a list of pairs of strings, tracing in the “u” mode now works.

bpo-26243 [https://bugs.python.org/issue?@action=redirect&bpo=26243]: Only the level argument to zlib.compress() is keyword argument now. The first argument is positional-only.

bpo-27038 [https://bugs.python.org/issue?@action=redirect&bpo=27038]: Expose the DirEntry type as os.DirEntry. Code patch by Jelle Zijlstra.

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Update os.fspath()/PyOS_FSPath() to check the return value of __fspath__() to be either str or bytes.

bpo-18726 [https://bugs.python.org/issue?@action=redirect&bpo=18726]: All optional parameters of the dump(), dumps(), load() and loads() functions and JSONEncoder and JSONDecoder class constructors in the json module are now keyword-only.

bpo-27319 [https://bugs.python.org/issue?@action=redirect&bpo=27319]: Methods selection_set(), selection_add(), selection_remove() and selection_toggle() of ttk.TreeView now allow passing multiple items as multiple arguments instead of passing them as a tuple. Deprecated undocumented ability of calling the selection() method with arguments.

bpo-27079 [https://bugs.python.org/issue?@action=redirect&bpo=27079]: Fixed curses.ascii functions isblank(), iscntrl() and ispunct().

bpo-27294 [https://bugs.python.org/issue?@action=redirect&bpo=27294]: Numerical state in the repr for Tkinter event objects is now represented as a combination of known flags.

bpo-27177 [https://bugs.python.org/issue?@action=redirect&bpo=27177]: Match objects in the re module now support index-like objects as group indices. Based on patches by Jeroen Demeyer and Xiang Zhang.

bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754]: Some functions (compile() etc) accepted a filename argument encoded as an iterable of integers. Now only strings and byte-like objects are accepted.

bpo-26536 [https://bugs.python.org/issue?@action=redirect&bpo=26536]: socket.ioctl now supports SIO_LOOPBACK_FAST_PATH. Patch by Daniel Stokes.

bpo-27048 [https://bugs.python.org/issue?@action=redirect&bpo=27048]: Prevents distutils failing on Windows when environment variables contain non-ASCII characters

bpo-27330 [https://bugs.python.org/issue?@action=redirect&bpo=27330]: Fixed possible leaks in the ctypes module.

bpo-27238 [https://bugs.python.org/issue?@action=redirect&bpo=27238]: Got rid of bare excepts in the turtle module. Original patch by Jelle Zijlstra.

bpo-27122 [https://bugs.python.org/issue?@action=redirect&bpo=27122]: When an exception is raised within the context being managed by a contextlib.ExitStack() and one of the exit stack generators catches and raises it in a chain, do not re-raise the original exception when exiting, let the new chained one through. This avoids the PEP 479 [https://peps.python.org/pep-0479/] bug described in issue25782.

bpo-16864 [https://bugs.python.org/issue?@action=redirect&bpo=16864]: sqlite3.Cursor.lastrowid now supports REPLACE statement. Initial patch by Alex LordThorsen.

bpo-26386 [https://bugs.python.org/issue?@action=redirect&bpo=26386]: Fixed ttk.TreeView selection operations with item id’s containing spaces.

bpo-8637 [https://bugs.python.org/issue?@action=redirect&bpo=8637]: Honor a pager set by the env var MANPAGER (in preference to one set by the env var PAGER).

bpo-16182 [https://bugs.python.org/issue?@action=redirect&bpo=16182]: Fix various functions in the “readline” module to use the locale encoding, and fix get_begidx() and get_endidx() to return code point indexes.

bpo-27392 [https://bugs.python.org/issue?@action=redirect&bpo=27392]: Add loop.connect_accepted_socket(). Patch by Jim Fulton.

IDLE

bpo-27477 [https://bugs.python.org/issue?@action=redirect&bpo=27477]: IDLE search dialogs now use ttk widgets.

bpo-27173 [https://bugs.python.org/issue?@action=redirect&bpo=27173]: Add ‘IDLE Modern Unix’ to the built-in key sets. Make the default key set depend on the platform. Add tests for the changes to the config module.

bpo-27452 [https://bugs.python.org/issue?@action=redirect&bpo=27452]: make command line “idle-test> python test_help.py” work. __file__ is relative when python is started in the file’s directory.

bpo-27452 [https://bugs.python.org/issue?@action=redirect&bpo=27452]: add line counter and crc to IDLE configHandler test dump.

bpo-27380 [https://bugs.python.org/issue?@action=redirect&bpo=27380]: IDLE: add query.py with base Query dialog and ttk widgets. Module had subclasses SectionName, ModuleName, and HelpSource, which are used to get information from users by configdialog and file =>Load Module. Each subclass has itw own validity checks. Using ModuleName allows users to edit bad module names instead of starting over. Add tests and delete the two files combined into the new one.

bpo-27372 [https://bugs.python.org/issue?@action=redirect&bpo=27372]: Test_idle no longer changes the locale.

bpo-27365 [https://bugs.python.org/issue?@action=redirect&bpo=27365]: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.

bpo-27245 [https://bugs.python.org/issue?@action=redirect&bpo=27245]: IDLE: Cleanly delete custom themes and key bindings. Previously, when IDLE was started from a console or by import, a cascade of warnings was emitted. Patch by Serhiy Storchaka.

bpo-24137 [https://bugs.python.org/issue?@action=redirect&bpo=24137]: Run IDLE, test_idle, and htest with tkinter default root disabled. Fix code and tests that fail with this restriction. Fix htests to not create a second and redundant root and mainloop.

bpo-27310 [https://bugs.python.org/issue?@action=redirect&bpo=27310]: Fix IDLE.app failure to launch on OS X due to vestigial import.

C API

bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754]: PyUnicode_FSDecoder() accepted a filename argument encoded as an iterable of integers. Now only strings and byte-like objects are accepted.

Build

bpo-28066 [https://bugs.python.org/issue?@action=redirect&bpo=28066]: Fix the logic that searches build directories for generated include files when building outside the source tree.

bpo-27442 [https://bugs.python.org/issue?@action=redirect&bpo=27442]: Expose the Android API level that python was built against, in sysconfig.get_config_vars() as ‘ANDROID_API_LEVEL’.

bpo-27434 [https://bugs.python.org/issue?@action=redirect&bpo=27434]: The interpreter that runs the cross-build, found in PATH, must now be of the same feature version (e.g. 3.6) as the source being built.

bpo-26930 [https://bugs.python.org/issue?@action=redirect&bpo=26930]: Update Windows builds to use OpenSSL 1.0.2h.

bpo-23968 [https://bugs.python.org/issue?@action=redirect&bpo=23968]: Rename the platform directory from plat-$(MACHDEP) to plat-$(PLATFORM_TRIPLET). Rename the config directory (LIBPL) from config-$(LDVERSION) to config-$(LDVERSION)-$(PLATFORM_TRIPLET). Install the platform specific _sysconfigdata module into the platform directory and rename it to include the ABIFLAGS.

Don’t use largefile support for GNU/Hurd.

Tools/Demos

bpo-27332 [https://bugs.python.org/issue?@action=redirect&bpo=27332]: Fixed the type of the first argument of module-level functions generated by Argument Clinic. Patch by Petr Viktorin.

bpo-27418 [https://bugs.python.org/issue?@action=redirect&bpo=27418]: Fixed Tools/importbench/importbench.py.

Documentation

bpo-19489 [https://bugs.python.org/issue?@action=redirect&bpo=19489]: Moved the search box from the sidebar to the header and footer of each page. Patch by Ammar Askar.

bpo-27285 [https://bugs.python.org/issue?@action=redirect&bpo=27285]: Update documentation to reflect the deprecation of pyvenv and normalize on the term “virtual environment”. Patch by Steve Piercy.

Tests

bpo-27027 [https://bugs.python.org/issue?@action=redirect&bpo=27027]: Added test.support.is_android that is True when this is an Android build.

Python 3.6.0 alpha 2

Release date: 2016-06-13

Security

bpo-26556 [https://bugs.python.org/issue?@action=redirect&bpo=26556]: Update expat to 2.1.1, fixes CVE 2015-1283 [https://www.cve.org/CVERecord?id=CVE-2015-1283].

Fix TLS stripping vulnerability in smtplib, CVE 2016-0772 [https://www.cve.org/CVERecord?id=CVE-2016-0772]. Reported by Team Oststrom.

bpo-26839 [https://bugs.python.org/issue?@action=redirect&bpo=26839]: On Linux, os.urandom() now calls getrandom() with GRND_NONBLOCK to fall back on reading /dev/urandom if the urandom entropy pool is not initialized yet. Patch written by Colm Buckley.

Core and Builtins

bpo-27095 [https://bugs.python.org/issue?@action=redirect&bpo=27095]: Simplified MAKE_FUNCTION and removed MAKE_CLOSURE opcodes. Patch by Demur Rumed.

bpo-27190 [https://bugs.python.org/issue?@action=redirect&bpo=27190]: Raise NotSupportedError if sqlite3 is older than 3.3.1. Patch by Dave Sawyer.

bpo-27286 [https://bugs.python.org/issue?@action=redirect&bpo=27286]: Fixed compiling BUILD_MAP_UNPACK_WITH_CALL opcode. Calling function with generalized unpacking (PEP 448) and conflicting keyword names could cause undefined behavior.

bpo-27140 [https://bugs.python.org/issue?@action=redirect&bpo=27140]: Added BUILD_CONST_KEY_MAP opcode.

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Add support for os.PathLike objects to open() (part of PEP 519 [https://peps.python.org/pep-0519/]).

bpo-27066 [https://bugs.python.org/issue?@action=redirect&bpo=27066]: Fixed SystemError if a custom opener (for open()) returns a negative number without setting an exception.

bpo-26983 [https://bugs.python.org/issue?@action=redirect&bpo=26983]: float() now always return an instance of exact float. The deprecation warning is emitted if __float__ returns an instance of a strict subclass of float. In a future versions of Python this can be an error.

bpo-27097 [https://bugs.python.org/issue?@action=redirect&bpo=27097]: Python interpreter is now about 7% faster due to optimized instruction decoding. Based on patch by Demur Rumed.

bpo-26647 [https://bugs.python.org/issue?@action=redirect&bpo=26647]: Python interpreter now uses 16-bit wordcode instead of bytecode. Patch by Demur Rumed.

bpo-23275 [https://bugs.python.org/issue?@action=redirect&bpo=23275]: Allow assigning to an empty target list in round brackets: () = iterable.

bpo-27243 [https://bugs.python.org/issue?@action=redirect&bpo=27243]: Update the __aiter__ protocol: instead of returning an awaitable that resolves to an asynchronous iterator, the asynchronous iterator should be returned directly. Doing the former will trigger a PendingDeprecationWarning.

Library

Comment out socket (SO_REUSEPORT) and posix (O_SHLOCK, O_EXLOCK) constants exposed on the API which are not implemented on GNU/Hurd. They would not work at runtime anyway.

bpo-27025 [https://bugs.python.org/issue?@action=redirect&bpo=27025]: Generated names for Tkinter widgets are now more meaningful and recognizable.

bpo-25455 [https://bugs.python.org/issue?@action=redirect&bpo=25455]: Fixed crashes in repr of recursive ElementTree.Element and functools.partial objects.

bpo-27294 [https://bugs.python.org/issue?@action=redirect&bpo=27294]: Improved repr for Tkinter event objects.

bpo-20508 [https://bugs.python.org/issue?@action=redirect&bpo=20508]: Improve exception message of IPv{4,6}Network.__getitem__. Patch by Gareth Rees.

bpo-21386 [https://bugs.python.org/issue?@action=redirect&bpo=21386]: Implement missing IPv4Address.is_global property. It was documented since 07a5610bae9d. Initial patch by Roger Luethi.

bpo-27029 [https://bugs.python.org/issue?@action=redirect&bpo=27029]: Removed deprecated support of universal newlines mode from ZipFile.open().

bpo-27030 [https://bugs.python.org/issue?@action=redirect&bpo=27030]: Unknown escapes consisting of '\' and an ASCII letter in regular expressions now are errors. The re.LOCALE flag now can be used only with bytes patterns.

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Add os.PathLike support to DirEntry (part of PEP 519 [https://peps.python.org/pep-0519/]). Initial patch by Jelle Zijlstra.

bpo-20900 [https://bugs.python.org/issue?@action=redirect&bpo=20900]: distutils register command now decodes HTTP responses correctly. Initial patch by ingrid.

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Add os.PathLike support to pathlib, removing its provisional status (part of PEP 519). Initial patch by Dusty Phillips.

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Add support for os.PathLike objects to os.fsencode() and os.fsdecode() (part of PEP 519 [https://peps.python.org/pep-0519/]).

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Introduce os.PathLike and os.fspath() (part of PEP 519 [https://peps.python.org/pep-0519/]).

A new version of typing.py provides several new classes and features: @overload outside stubs, Reversible, DefaultDict, Text, ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug fixes (note that some of the new features are not yet implemented in mypy or other static analyzers). Also classes for PEP 492 [https://peps.python.org/pep-0492/] (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact they made it into 3.5.1 but were never mentioned).

bpo-25738 [https://bugs.python.org/issue?@action=redirect&bpo=25738]: Stop http.server.BaseHTTPRequestHandler.send_error() from sending a message body for 205 Reset Content. Also, don’t send Content header fields in responses that don’t have a body. Patch by Susumu Koshiba.

bpo-21313 [https://bugs.python.org/issue?@action=redirect&bpo=21313]: Fix the “platform” module to tolerate when sys.version contains truncated build information.

bpo-23883 [https://bugs.python.org/issue?@action=redirect&bpo=23883]: Added missing APIs to __all__ to match the documented APIs for the following modules: cgi, mailbox, mimetypes, plistlib and smtpd. Patches by Jacek Kołodziej.

bpo-27164 [https://bugs.python.org/issue?@action=redirect&bpo=27164]: In the zlib module, allow decompressing raw Deflate streams with a predefined zdict. Based on patch by Xiang Zhang.

bpo-24291 [https://bugs.python.org/issue?@action=redirect&bpo=24291]: Fix wsgiref.simple_server.WSGIRequestHandler to completely write data to the client. Previously it could do partial writes and truncate data. Also, wsgiref.handler.ServerHandler can now handle stdout doing partial writes, but this is deprecated.

bpo-21272 [https://bugs.python.org/issue?@action=redirect&bpo=21272]: Use _sysconfigdata.py to initialize distutils.sysconfig.

bpo-19611 [https://bugs.python.org/issue?@action=redirect&bpo=19611]: inspect now reports the implicit .0 parameters generated by the compiler for comprehension and generator expression scopes as if they were positional-only parameters called implicit0. Patch by Jelle Zijlstra.

bpo-26809 [https://bugs.python.org/issue?@action=redirect&bpo=26809]: Add __all__ to string. Patch by Emanuel Barry.

bpo-26373 [https://bugs.python.org/issue?@action=redirect&bpo=26373]: subprocess.Popen.communicate now correctly ignores BrokenPipeError when the child process dies before .communicate() is called in more/all circumstances.

signal, socket, and ssl module IntEnum constant name lookups now return a consistent name for values having multiple names. Ex: signal.Signals(6) now refers to itself as signal.SIGALRM rather than flipping between that and signal.SIGIOT based on the interpreter’s hash randomization seed.

bpo-27167 [https://bugs.python.org/issue?@action=redirect&bpo=27167]: Clarify the subprocess.CalledProcessError error message text when the child process died due to a signal.

bpo-25931 [https://bugs.python.org/issue?@action=redirect&bpo=25931]: Don’t define socketserver.Forking* names on platforms such as Windows that do not support os.fork().

bpo-21776 [https://bugs.python.org/issue?@action=redirect&bpo=21776]: distutils.upload now correctly handles HTTPError. Initial patch by Claudiu Popa.

bpo-26526 [https://bugs.python.org/issue?@action=redirect&bpo=26526]: Replace custom parse tree validation in the parser module with a simple DFA validator.

bpo-27114 [https://bugs.python.org/issue?@action=redirect&bpo=27114]: Fix SSLContext._load_windows_store_certs fails with PermissionError

bpo-18383 [https://bugs.python.org/issue?@action=redirect&bpo=18383]: Avoid creating duplicate filters when using filterwarnings and simplefilter. Based on patch by Alex Shkop.

bpo-23026 [https://bugs.python.org/issue?@action=redirect&bpo=23026]: winreg.QueryValueEx() now return an integer for REG_QWORD type.

bpo-26741 [https://bugs.python.org/issue?@action=redirect&bpo=26741]: subprocess.Popen destructor now emits a ResourceWarning warning if the child process is still running.

bpo-27056 [https://bugs.python.org/issue?@action=redirect&bpo=27056]: Optimize pickle.load() and pickle.loads(), up to 10% faster to deserialize a lot of small objects.

bpo-21271 [https://bugs.python.org/issue?@action=redirect&bpo=21271]: New keyword only parameters in reset_mock call.

IDLE

bpo-5124 [https://bugs.python.org/issue?@action=redirect&bpo=5124]: Paste with text selected now replaces the selection on X11. This matches how paste works on Windows, Mac, most modern Linux apps, and ttk widgets. Original patch by Serhiy Storchaka.

bpo-24750 [https://bugs.python.org/issue?@action=redirect&bpo=24750]: Switch all scrollbars in IDLE to ttk versions. Where needed, minimal tests are added to cover changes.

bpo-24759 [https://bugs.python.org/issue?@action=redirect&bpo=24759]: IDLE requires tk 8.5 and availability ttk widgets. Delete now unneeded tk version tests and code for older versions. Add test for IDLE syntax colorizer.

bpo-27239 [https://bugs.python.org/issue?@action=redirect&bpo=27239]: idlelib.macosx.isXyzTk functions initialize as needed.

bpo-27262 [https://bugs.python.org/issue?@action=redirect&bpo=27262]: move Aqua unbinding code, which enable context menus, to macosx.

bpo-24759 [https://bugs.python.org/issue?@action=redirect&bpo=24759]: Make clear in idlelib.idle_test.__init__ that the directory is a private implementation of test.test_idle and tool for maintainers.

bpo-27196 [https://bugs.python.org/issue?@action=redirect&bpo=27196]: Stop ‘ThemeChanged’ warnings when running IDLE tests. These persisted after other warnings were suppressed in #20567. Apply Serhiy Storchaka’s update_idletasks solution to four test files. Record this additional advice in idle_test/README.txt

bpo-20567 [https://bugs.python.org/issue?@action=redirect&bpo=20567]: Revise idle_test/README.txt with advice about avoiding tk warning messages from tests. Apply advice to several IDLE tests.

bpo-24225 [https://bugs.python.org/issue?@action=redirect&bpo=24225]: Update idlelib/README.txt with new file names and event handlers.

bpo-27156 [https://bugs.python.org/issue?@action=redirect&bpo=27156]: Remove obsolete code not used by IDLE.

bpo-27117 [https://bugs.python.org/issue?@action=redirect&bpo=27117]: Make colorizer htest and turtledemo work with dark themes. Move code for configuring text widget colors to a new function.

bpo-24225 [https://bugs.python.org/issue?@action=redirect&bpo=24225]: Rename many idlelib/*.py and idle_test/test_*.py files. Edit files to replace old names with new names when the old name referred to the module rather than the class it contained. See the issue and IDLE section in What’s New in 3.6 for more.

bpo-26673 [https://bugs.python.org/issue?@action=redirect&bpo=26673]: When tk reports font size as 0, change to size 10. Such fonts on Linux prevented the configuration dialog from opening.

bpo-21939 [https://bugs.python.org/issue?@action=redirect&bpo=21939]: Add test for IDLE’s percolator. Original patch by Saimadhav Heblikar.

bpo-21676 [https://bugs.python.org/issue?@action=redirect&bpo=21676]: Add test for IDLE’s replace dialog. Original patch by Saimadhav Heblikar.

bpo-18410 [https://bugs.python.org/issue?@action=redirect&bpo=18410]: Add test for IDLE’s search dialog. Original patch by Westley Martínez.

bpo-21703 [https://bugs.python.org/issue?@action=redirect&bpo=21703]: Add test for undo delegator. Patch mostly by Saimadhav Heblikar .

bpo-27044 [https://bugs.python.org/issue?@action=redirect&bpo=27044]: Add ConfigDialog.remove_var_callbacks to stop memory leaks.

bpo-23977 [https://bugs.python.org/issue?@action=redirect&bpo=23977]: Add more asserts to test_delegator.

Documentation

bpo-16484 [https://bugs.python.org/issue?@action=redirect&bpo=16484]: Change the default PYTHONDOCS URL to “https:”, and fix the resulting links to use lowercase. Patch by Sean Rodman, test by Kaushik Nadikuditi.

bpo-24136 [https://bugs.python.org/issue?@action=redirect&bpo=24136]: Document the new PEP 448 [https://peps.python.org/pep-0448/] unpacking syntax of 3.5.

bpo-22558 [https://bugs.python.org/issue?@action=redirect&bpo=22558]: Add remaining doc links to source code for Python-coded modules. Patch by Yoni Lavi.

Tests

bpo-25285 [https://bugs.python.org/issue?@action=redirect&bpo=25285]: regrtest now uses subprocesses when the -j1 command line option is used: each test file runs in a fresh child process. Before, the -j1 option was ignored.

bpo-25285 [https://bugs.python.org/issue?@action=redirect&bpo=25285]: Tools/buildbot/test.bat script now uses -j1 by default to run each test file in fresh child process.

Windows

bpo-27064 [https://bugs.python.org/issue?@action=redirect&bpo=27064]: The py.exe launcher now defaults to Python 3. The Windows launcher py.exe no longer prefers an installed Python 2 version over Python 3 by default when used interactively.

bpo-17500 [https://bugs.python.org/issue?@action=redirect&bpo=17500]: Remove unused and outdated icons. (See also: https://github.com/python/pythondotorg/issues/945)

Build

bpo-27229 [https://bugs.python.org/issue?@action=redirect&bpo=27229]: Fix the cross-compiling pgen rule for in-tree builds. Patch by Xavier de Gaye.

bpo-26930 [https://bugs.python.org/issue?@action=redirect&bpo=26930]: Update OS X 10.5+ 32-bit-only installer to build and link with OpenSSL 1.0.2h.

C API

bpo-27186 [https://bugs.python.org/issue?@action=redirect&bpo=27186]: Add the PyOS_FSPath() function (part of PEP 519 [https://peps.python.org/pep-0519/]).

bpo-26282 [https://bugs.python.org/issue?@action=redirect&bpo=26282]: PyArg_ParseTupleAndKeywords() now supports positional-only parameters.

Tools/Demos

bpo-26282 [https://bugs.python.org/issue?@action=redirect&bpo=26282]: Argument Clinic now supports positional-only and keyword parameters in the same function.

Python 3.6.0 alpha 1

Release date: 2016-05-16

Security

bpo-26657 [https://bugs.python.org/issue?@action=redirect&bpo=26657]: Fix directory traversal vulnerability with http.server on Windows. This fixes a regression that was introduced in 3.3.4rc1 and 3.4.0rc1. Based on patch by Philipp Hagemeister.

bpo-26313 [https://bugs.python.org/issue?@action=redirect&bpo=26313]: ssl.py _load_windows_store_certs fails if windows cert store is empty. Patch by Baji.

bpo-25939 [https://bugs.python.org/issue?@action=redirect&bpo=25939]: On Windows open the cert store readonly in ssl.enum_certificates.

Core and Builtins

bpo-20041 [https://bugs.python.org/issue?@action=redirect&bpo=20041]: Fixed TypeError when frame.f_trace is set to None. Patch by Xavier de Gaye.

bpo-26168 [https://bugs.python.org/issue?@action=redirect&bpo=26168]: Fixed possible refleaks in failing Py_BuildValue() with the “N” format unit.

bpo-26991 [https://bugs.python.org/issue?@action=redirect&bpo=26991]: Fix possible refleak when creating a function with annotations.

bpo-27039 [https://bugs.python.org/issue?@action=redirect&bpo=27039]: Fixed bytearray.remove() for values greater than 127. Based on patch by Joe Jevnik.

bpo-23640 [https://bugs.python.org/issue?@action=redirect&bpo=23640]: int.from_bytes() no longer bypasses constructors for subclasses.

bpo-27005 [https://bugs.python.org/issue?@action=redirect&bpo=27005]: Optimized the float.fromhex() class method for exact float. It is now 2 times faster.

bpo-18531 [https://bugs.python.org/issue?@action=redirect&bpo=18531]: Single var-keyword argument of dict subtype was passed unscathed to the C-defined function. Now it is converted to exact dict.

bpo-26811 [https://bugs.python.org/issue?@action=redirect&bpo=26811]: gc.get_objects() no longer contains a broken tuple with NULL pointer.

bpo-20120 [https://bugs.python.org/issue?@action=redirect&bpo=20120]: Use RawConfigParser for .pypirc parsing, removing support for interpolation unintentionally added with move to Python 3. Behavior no longer does any interpolation in .pypirc files, matching behavior in Python 2.7 and Setuptools 19.0.

bpo-26249 [https://bugs.python.org/issue?@action=redirect&bpo=26249]: Memory functions of the PyMem_Malloc() domain (PYMEM_DOMAIN_MEM) now use the pymalloc allocator rather than system malloc(). Applications calling PyMem_Malloc() without holding the GIL can now crash: use PYTHONMALLOC=debug environment variable to validate the usage of memory allocators in your application.

bpo-26802 [https://bugs.python.org/issue?@action=redirect&bpo=26802]: Optimize function calls only using unpacking like func(*tuple) (no other positional argument, no keyword): avoid copying the tuple. Patch written by Joe Jevnik.

bpo-26659 [https://bugs.python.org/issue?@action=redirect&bpo=26659]: Make the builtin slice type support cycle collection.

bpo-26718 [https://bugs.python.org/issue?@action=redirect&bpo=26718]: super.__init__ no longer leaks memory if called multiple times. NOTE: A direct call of super.__init__ is not endorsed!

bpo-27138 [https://bugs.python.org/issue?@action=redirect&bpo=27138]: Fix the doc comment for FileFinder.find_spec().

bpo-27147 [https://bugs.python.org/issue?@action=redirect&bpo=27147]: Mention PEP 420 [https://peps.python.org/pep-0420/] in the importlib docs.

bpo-25339 [https://bugs.python.org/issue?@action=redirect&bpo=25339]: PYTHONIOENCODING now has priority over locale in setting the error handler for stdin and stdout.

bpo-26494 [https://bugs.python.org/issue?@action=redirect&bpo=26494]: Fixed crash on iterating exhausting iterators. Affected classes are generic sequence iterators, iterators of str, bytes, bytearray, list, tuple, set, frozenset, dict, OrderedDict, corresponding views and os.scandir() iterator.

bpo-26574 [https://bugs.python.org/issue?@action=redirect&bpo=26574]: Optimize bytes.replace(b'', b'.') and bytearray.replace(b'', b'.'). Patch written by Josh Snider.

bpo-26581 [https://bugs.python.org/issue?@action=redirect&bpo=26581]: If coding cookie is specified multiple times on a line in Python source code file, only the first one is taken to account.

bpo-19711 [https://bugs.python.org/issue?@action=redirect&bpo=19711]: Add tests for reloading namespace packages.

bpo-21099 [https://bugs.python.org/issue?@action=redirect&bpo=21099]: Switch applicable importlib tests to use PEP 451 [https://peps.python.org/pep-0451/] API.

bpo-26563 [https://bugs.python.org/issue?@action=redirect&bpo=26563]: Debug hooks on Python memory allocators now raise a fatal error if functions of the PyMem_Malloc() family are called without holding the GIL.

bpo-26564 [https://bugs.python.org/issue?@action=redirect&bpo=26564]: On error, the debug hooks on Python memory allocators now use the tracemalloc module to get the traceback where a memory block was allocated.

bpo-26558 [https://bugs.python.org/issue?@action=redirect&bpo=26558]: The debug hooks on Python memory allocator PyObject_Malloc() now detect when functions are called without holding the GIL.

bpo-26516 [https://bugs.python.org/issue?@action=redirect&bpo=26516]: Add PYTHONMALLOC environment variable to set the Python memory allocators and/or install debug hooks.

bpo-26516 [https://bugs.python.org/issue?@action=redirect&bpo=26516]: The PyMem_SetupDebugHooks() function can now also be used on Python compiled in release mode.

bpo-26516 [https://bugs.python.org/issue?@action=redirect&bpo=26516]: The PYTHONMALLOCSTATS environment variable can now also be used on Python compiled in release mode. It now has no effect if set to an empty string.

bpo-26516 [https://bugs.python.org/issue?@action=redirect&bpo=26516]: In debug mode, debug hooks are now also installed on Python memory allocators when Python is configured without pymalloc.

bpo-26464 [https://bugs.python.org/issue?@action=redirect&bpo=26464]: Fix str.translate() when string is ASCII and first replacements removes character, but next replacement uses a non-ASCII character or a string longer than 1 character. Regression introduced in Python 3.5.0.

bpo-22836 [https://bugs.python.org/issue?@action=redirect&bpo=22836]: Ensure exception reports from PyErr_Display() and PyErr_WriteUnraisable() are sensible even when formatting them produces secondary errors. This affects the reports produced by sys.__excepthook__() and when __del__() raises an exception.

bpo-26302 [https://bugs.python.org/issue?@action=redirect&bpo=26302]: Correct behavior to reject comma as a legal character for cookie names.

bpo-26136 [https://bugs.python.org/issue?@action=redirect&bpo=26136]: Upgrade the warning when a generator raises StopIteration from PendingDeprecationWarning to DeprecationWarning. Patch by Anish Shah.

bpo-26204 [https://bugs.python.org/issue?@action=redirect&bpo=26204]: The compiler now ignores all constant statements: bytes, str, int, float, complex, name constants (None, False, True), Ellipsis and ast.Constant; not only str and int. For example, 1.0 is now ignored in def f(): 1.0.

bpo-4806 [https://bugs.python.org/issue?@action=redirect&bpo=4806]: Avoid masking the original TypeError exception when using star (*) unpacking in function calls. Based on patch by Hagen Fürstenau and Daniel Urban.

bpo-26146 [https://bugs.python.org/issue?@action=redirect&bpo=26146]: Add a new kind of AST node: ast.Constant. It can be used by external AST optimizers, but the compiler does not emit directly such node.

bpo-23601 [https://bugs.python.org/issue?@action=redirect&bpo=23601]: Sped-up allocation of dict key objects by using Python’s small object allocator. (Contributed by Julian Taylor.)

bpo-18018 [https://bugs.python.org/issue?@action=redirect&bpo=18018]: Import raises ImportError instead of SystemError if a relative import is attempted without a known parent package.

bpo-25843 [https://bugs.python.org/issue?@action=redirect&bpo=25843]: When compiling code, don’t merge constants if they are equal but have a different types. For example, f1, f2 = lambda: 1, lambda: 1.0 is now correctly compiled to two different functions: f1() returns 1 (int) and f2() returns 1.0 (float), even if 1 and 1.0 are equal.

bpo-26107 [https://bugs.python.org/issue?@action=redirect&bpo=26107]: The format of the co_lnotab attribute of code objects changes to support negative line number delta.

bpo-26154 [https://bugs.python.org/issue?@action=redirect&bpo=26154]: Add a new private _PyThreadState_UncheckedGet() function to get the current Python thread state, but don’t issue a fatal error if it is NULL. This new function must be used instead of accessing directly the _PyThreadState_Current variable. The variable is no more exposed since Python 3.5.1 to hide the exact implementation of atomic C types, to avoid compiler issues.

bpo-25791 [https://bugs.python.org/issue?@action=redirect&bpo=25791]: If __package__ != __spec__.parent or if neither __package__ or __spec__ are defined then ImportWarning is raised.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: [UPDATE] Comment out the one of the pickleability tests in _PyObject_GetState() due to regressions observed in Cython-based projects.

bpo-25961 [https://bugs.python.org/issue?@action=redirect&bpo=25961]: Disallowed null characters in the type name.

bpo-25973 [https://bugs.python.org/issue?@action=redirect&bpo=25973]: Fix segfault when an invalid nonlocal statement binds a name starting with two underscores.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: Instances of extension types with a state that aren’t subclasses of list or dict and haven’t implemented any pickle-related methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__, or __getstate__), can no longer be pickled. Including memoryview.

bpo-20440 [https://bugs.python.org/issue?@action=redirect&bpo=20440]: Massive replacing unsafe attribute setting code with special macro Py_SETREF.

bpo-25766 [https://bugs.python.org/issue?@action=redirect&bpo=25766]: Special method __bytes__() now works in str subclasses.

bpo-25421 [https://bugs.python.org/issue?@action=redirect&bpo=25421]: __sizeof__ methods of builtin types now use dynamic basic size. This allows sys.getsize() to work correctly with their subclasses with __slots__ defined.

bpo-25709 [https://bugs.python.org/issue?@action=redirect&bpo=25709]: Fixed problem with in-place string concatenation and utf-8 cache.

bpo-5319 [https://bugs.python.org/issue?@action=redirect&bpo=5319]: New Py_FinalizeEx() API allowing Python to set an exit status of 120 on failure to flush buffered streams.

bpo-25485 [https://bugs.python.org/issue?@action=redirect&bpo=25485]: telnetlib.Telnet is now a context manager.

bpo-24097 [https://bugs.python.org/issue?@action=redirect&bpo=24097]: Fixed crash in object.__reduce__() if slot name is freed inside __getattr__.

bpo-24731 [https://bugs.python.org/issue?@action=redirect&bpo=24731]: Fixed crash on converting objects with special methods __bytes__, __trunc__, and __float__ returning instances of subclasses of bytes, int, and float to subclasses of bytes, int, and float correspondingly.

bpo-25630 [https://bugs.python.org/issue?@action=redirect&bpo=25630]: Fix a possible segfault during argument parsing in functions that accept filesystem paths.

bpo-23564 [https://bugs.python.org/issue?@action=redirect&bpo=23564]: Fixed a partially broken sanity check in the _posixsubprocess internals regarding how fds_to_pass were passed to the child. The bug had no actual impact as subprocess.py already avoided it.

bpo-25388 [https://bugs.python.org/issue?@action=redirect&bpo=25388]: Fixed tokenizer crash when processing undecodable source code with a null byte.

bpo-25462 [https://bugs.python.org/issue?@action=redirect&bpo=25462]: The hash of the key now is calculated only once in most operations in C implementation of OrderedDict.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: Default implementation of __reduce__ and __reduce_ex__ now rejects builtin types with not defined __new__.

bpo-24802 [https://bugs.python.org/issue?@action=redirect&bpo=24802]: Avoid buffer overreads when int(), float(), compile(), exec() and eval() are passed bytes-like objects. These objects are not necessarily terminated by a null byte, but the functions assumed they were.

bpo-25555 [https://bugs.python.org/issue?@action=redirect&bpo=25555]: Fix parser and AST: fill lineno and col_offset of “arg” node when compiling AST from Python objects.

bpo-24726 [https://bugs.python.org/issue?@action=redirect&bpo=24726]: Fixed a crash and leaking NULL in repr() of OrderedDict that was mutated by direct calls of dict methods.

bpo-25449 [https://bugs.python.org/issue?@action=redirect&bpo=25449]: Iterating OrderedDict with keys with unstable hash now raises KeyError in C implementations as well as in Python implementation.

bpo-25395 [https://bugs.python.org/issue?@action=redirect&bpo=25395]: Fixed crash when highly nested OrderedDict structures were garbage collected.

bpo-25401 [https://bugs.python.org/issue?@action=redirect&bpo=25401]: Optimize bytes.fromhex() and bytearray.fromhex(): they are now between 2x and 3.5x faster.

bpo-25399 [https://bugs.python.org/issue?@action=redirect&bpo=25399]: Optimize bytearray % args using the new private _PyBytesWriter API. Formatting is now between 2.5 and 5 times faster.

bpo-25274 [https://bugs.python.org/issue?@action=redirect&bpo=25274]: sys.setrecursionlimit() now raises a RecursionError if the new recursion limit is too low depending at the current recursion depth. Modify also the “lower-water mark” formula to make it monotonic. This mark is used to decide when the overflowed flag of the thread state is reset.

bpo-24402 [https://bugs.python.org/issue?@action=redirect&bpo=24402]: Fix input() to prompt to the redirected stdout when sys.stdout.fileno() fails.

bpo-25349 [https://bugs.python.org/issue?@action=redirect&bpo=25349]: Optimize bytes % args using the new private _PyBytesWriter API. Formatting is now up to 2 times faster.

bpo-24806 [https://bugs.python.org/issue?@action=redirect&bpo=24806]: Prevent builtin types that are not allowed to be subclassed from being subclassed through multiple inheritance.

bpo-25301 [https://bugs.python.org/issue?@action=redirect&bpo=25301]: The UTF-8 decoder is now up to 15 times as fast for error handlers: ignore, replace and surrogateescape.

bpo-24848 [https://bugs.python.org/issue?@action=redirect&bpo=24848]: Fixed a number of bugs in UTF-7 decoding of misformed data.

bpo-25267 [https://bugs.python.org/issue?@action=redirect&bpo=25267]: The UTF-8 encoder is now up to 75 times as fast for error handlers: ignore, replace, surrogateescape, surrogatepass. Patch co-written with Serhiy Storchaka.

bpo-25280 [https://bugs.python.org/issue?@action=redirect&bpo=25280]: Import trace messages emitted in verbose (-v) mode are no longer formatted twice.

bpo-25227 [https://bugs.python.org/issue?@action=redirect&bpo=25227]: Optimize ASCII and latin1 encoders with the surrogateescape error handler: the encoders are now up to 3 times as fast. Initial patch written by Serhiy Storchaka.

bpo-25003 [https://bugs.python.org/issue?@action=redirect&bpo=25003]: On Solaris 11.3 or newer, os.urandom() now uses the getrandom() function instead of the getentropy() function. The getentropy() function is blocking to generate very good quality entropy, os.urandom() doesn’t need such high-quality entropy.

bpo-9232 [https://bugs.python.org/issue?@action=redirect&bpo=9232]: Modify Python’s grammar to allow trailing commas in the argument list of a function declaration. For example, “def f(*, a = 3,): pass” is now legal. Patch from Mark Dickinson.

bpo-24965 [https://bugs.python.org/issue?@action=redirect&bpo=24965]: Implement PEP 498 [https://peps.python.org/pep-0498/] “Literal String Interpolation”. This allows you to embed expressions inside f-strings, which are converted to normal strings at run time. Given x=3, then f’value={x}’ == ‘value=3’. Patch by Eric V. Smith.

bpo-26478 [https://bugs.python.org/issue?@action=redirect&bpo=26478]: Fix semantic bugs when using binary operators with dictionary views and tuples.

bpo-26171 [https://bugs.python.org/issue?@action=redirect&bpo=26171]: Fix possible integer overflow and heap corruption in zipimporter.get_data().

bpo-25660 [https://bugs.python.org/issue?@action=redirect&bpo=25660]: Fix TAB key behaviour in REPL with readline.

bpo-26288 [https://bugs.python.org/issue?@action=redirect&bpo=26288]: Optimize PyLong_AsDouble.

bpo-26289 [https://bugs.python.org/issue?@action=redirect&bpo=26289]: Optimize floor and modulo division for single-digit longs. Microbenchmarks show 2-2.5x improvement. Built-in ‘divmod’ function is now also ~10% faster. (See also: bpo-26315 [https://bugs.python.org/issue?@action=redirect&bpo=26315])

bpo-25887 [https://bugs.python.org/issue?@action=redirect&bpo=25887]: Raise a RuntimeError when a coroutine object is awaited more than once.

Library

bpo-27057 [https://bugs.python.org/issue?@action=redirect&bpo=27057]: Fix os.set_inheritable() on Android, ioctl() is blocked by SELinux and fails with EACCESS. The function now falls back to fcntl(). Patch written by Michał Bednarski.

bpo-27014 [https://bugs.python.org/issue?@action=redirect&bpo=27014]: Fix infinite recursion using typing.py. Thanks to Kalle Tuure!

bpo-27031 [https://bugs.python.org/issue?@action=redirect&bpo=27031]: Removed dummy methods in Tkinter widget classes: tk_menuBar() and tk_bindForTraversal().

bpo-14132 [https://bugs.python.org/issue?@action=redirect&bpo=14132]: Fix urllib.request redirect handling when the target only has a query string. Original fix by Ján Janech.

bpo-17214 [https://bugs.python.org/issue?@action=redirect&bpo=17214]: The “urllib.request” module now percent-encodes non-ASCII bytes found in redirect target URLs. Some servers send Location header fields with non-ASCII bytes, but “http.client” requires the request target to be ASCII-encodable, otherwise a UnicodeEncodeError is raised. Based on patch by Christian Heimes.

bpo-27033 [https://bugs.python.org/issue?@action=redirect&bpo=27033]: The default value of the decode_data parameter for smtpd.SMTPChannel and smtpd.SMTPServer constructors is changed to False.

bpo-27034 [https://bugs.python.org/issue?@action=redirect&bpo=27034]: Removed deprecated class asynchat.fifo.

bpo-26870 [https://bugs.python.org/issue?@action=redirect&bpo=26870]: Added readline.set_auto_history(), which can stop entries being automatically added to the history list. Based on patch by Tyler Crompton.

bpo-26039 [https://bugs.python.org/issue?@action=redirect&bpo=26039]: zipfile.ZipFile.open() can now be used to write data into a ZIP file, as well as for extracting data. Patch by Thomas Kluyver.

bpo-26892 [https://bugs.python.org/issue?@action=redirect&bpo=26892]: Honor debuglevel flag in urllib.request.HTTPHandler. Patch contributed by Chi Hsuan Yen.

bpo-22274 [https://bugs.python.org/issue?@action=redirect&bpo=22274]: In the subprocess module, allow stderr to be redirected to stdout even when stdout is not redirected. Patch by Akira Li.

bpo-26807 [https://bugs.python.org/issue?@action=redirect&bpo=26807]: mock_open ‘files’ no longer error on readline at end of file. Patch from Yolanda Robla.

bpo-25745 [https://bugs.python.org/issue?@action=redirect&bpo=25745]: Fixed leaking a userptr in curses panel destructor.

bpo-26977 [https://bugs.python.org/issue?@action=redirect&bpo=26977]: Removed unnecessary, and ignored, call to sum of squares helper in statistics.pvariance.

bpo-26002 [https://bugs.python.org/issue?@action=redirect&bpo=26002]: Use bisect in statistics.median instead of a linear search. Patch by Upendra Kuma.

bpo-25974 [https://bugs.python.org/issue?@action=redirect&bpo=25974]: Make use of new Decimal.as_integer_ratio() method in statistics module. Patch by Stefan Krah.

bpo-26996 [https://bugs.python.org/issue?@action=redirect&bpo=26996]: Add secrets module as described in PEP 506 [https://peps.python.org/pep-0506/].

bpo-26881 [https://bugs.python.org/issue?@action=redirect&bpo=26881]: The modulefinder module now supports extended opcode arguments.

bpo-23815 [https://bugs.python.org/issue?@action=redirect&bpo=23815]: Fixed crashes related to directly created instances of types in _tkinter and curses.panel modules.

bpo-17765 [https://bugs.python.org/issue?@action=redirect&bpo=17765]: weakref.ref() no longer silently ignores keyword arguments. Patch by Georg Brandl.

bpo-26873 [https://bugs.python.org/issue?@action=redirect&bpo=26873]: xmlrpc now raises ResponseError on unsupported type tags instead of silently return incorrect result.

bpo-26915 [https://bugs.python.org/issue?@action=redirect&bpo=26915]: The __contains__ methods in the collections ABCs now check for identity before checking equality. This better matches the behavior of the concrete classes, allows sensible handling of NaNs, and makes it easier to reason about container invariants.

bpo-26711 [https://bugs.python.org/issue?@action=redirect&bpo=26711]: Fixed the comparison of plistlib.Data with other types.

bpo-24114 [https://bugs.python.org/issue?@action=redirect&bpo=24114]: Fix an uninitialized variable in ctypes.util. The bug only occurs on SunOS when the ctypes implementation searches for the crle program. Patch by Xiang Zhang. Tested on SunOS by Kees Bos.

bpo-26864 [https://bugs.python.org/issue?@action=redirect&bpo=26864]: In urllib.request, change the proxy bypass host checking against no_proxy to be case-insensitive, and to not match unrelated host names that happen to have a bypassed hostname as a suffix. Patch by Xiang Zhang.

bpo-24902 [https://bugs.python.org/issue?@action=redirect&bpo=24902]: Print server URL on http.server startup. Initial patch by Felix Kaiser.

bpo-25788 [https://bugs.python.org/issue?@action=redirect&bpo=25788]: fileinput.hook_encoded() now supports an “errors” argument for passing to open. Original patch by Joseph Hackman.

bpo-26634 [https://bugs.python.org/issue?@action=redirect&bpo=26634]: recursive_repr() now sets __qualname__ of wrapper. Patch by Xiang Zhang.

bpo-26804 [https://bugs.python.org/issue?@action=redirect&bpo=26804]: urllib.request will prefer lower_case proxy environment variables over UPPER_CASE or Mixed_Case ones. Patch contributed by Hans-Peter Jansen.

bpo-26837 [https://bugs.python.org/issue?@action=redirect&bpo=26837]: assertSequenceEqual() now correctly outputs non-stringified differing items (like bytes in the -b mode). This affects assertListEqual() and assertTupleEqual().

bpo-26041 [https://bugs.python.org/issue?@action=redirect&bpo=26041]: Remove “will be removed in Python 3.7” from deprecation messages of platform.dist() and platform.linux_distribution(). Patch by Kumaripaba Miyurusara Athukorala.

bpo-26822 [https://bugs.python.org/issue?@action=redirect&bpo=26822]: itemgetter, attrgetter and methodcaller objects no longer silently ignore keyword arguments.

bpo-26733 [https://bugs.python.org/issue?@action=redirect&bpo=26733]: Disassembling a class now disassembles class and static methods. Patch by Xiang Zhang.

bpo-26801 [https://bugs.python.org/issue?@action=redirect&bpo=26801]: Fix error handling in shutil.get_terminal_size(), catch AttributeError instead of NameError. Patch written by Emanuel Barry.

bpo-24838 [https://bugs.python.org/issue?@action=redirect&bpo=24838]: tarfile’s ustar and gnu formats now correctly calculate name and link field limits for multibyte character encodings like utf-8.

bpo-26717 [https://bugs.python.org/issue?@action=redirect&bpo=26717]: Stop encoding Latin-1-ized WSGI paths with UTF-8. Patch by Anthony Sottile.

bpo-26782 [https://bugs.python.org/issue?@action=redirect&bpo=26782]: Add STARTUPINFO to subprocess.__all__ on Windows.

bpo-26404 [https://bugs.python.org/issue?@action=redirect&bpo=26404]: Add context manager to socketserver. Patch by Aviv Palivoda.

bpo-26735 [https://bugs.python.org/issue?@action=redirect&bpo=26735]: Fix os.urandom() on Solaris 11.3 and newer when reading more than 1,024 bytes: call getrandom() multiple times with a limit of 1024 bytes per call.

bpo-26585 [https://bugs.python.org/issue?@action=redirect&bpo=26585]: Eliminate http.server._quote_html() and use html.escape(quote=False). Patch by Xiang Zhang.

bpo-26685 [https://bugs.python.org/issue?@action=redirect&bpo=26685]: Raise OSError if closing a socket fails.

bpo-16329 [https://bugs.python.org/issue?@action=redirect&bpo=16329]: Add .webm to mimetypes.types_map. Patch by Giampaolo Rodola’.

bpo-13952 [https://bugs.python.org/issue?@action=redirect&bpo=13952]: Add .csv to mimetypes.types_map. Patch by Geoff Wilson.

bpo-26587 [https://bugs.python.org/issue?@action=redirect&bpo=26587]: the site module now allows .pth files to specify files to be added to sys.path (e.g. zip files).

bpo-25609 [https://bugs.python.org/issue?@action=redirect&bpo=25609]: Introduce contextlib.AbstractContextManager and typing.ContextManager.

bpo-26709 [https://bugs.python.org/issue?@action=redirect&bpo=26709]: Fixed Y2038 problem in loading binary PLists.

bpo-23735 [https://bugs.python.org/issue?@action=redirect&bpo=23735]: Handle terminal resizing with Readline 6.3+ by installing our own SIGWINCH handler. Patch by Eric Price.

bpo-25951 [https://bugs.python.org/issue?@action=redirect&bpo=25951]: Change SSLSocket.sendall() to return None, as explicitly documented for plain socket objects. Patch by Aviv Palivoda.

bpo-26586 [https://bugs.python.org/issue?@action=redirect&bpo=26586]: In http.server, respond with “413 Request header fields too large” if there are too many header fields to parse, rather than killing the connection and raising an unhandled exception. Patch by Xiang Zhang.

bpo-26676 [https://bugs.python.org/issue?@action=redirect&bpo=26676]: Added missing XMLPullParser to ElementTree.__all__.

bpo-22854 [https://bugs.python.org/issue?@action=redirect&bpo=22854]: Change BufferedReader.writable() and BufferedWriter.readable() to always return False.

bpo-26492 [https://bugs.python.org/issue?@action=redirect&bpo=26492]: Exhausted iterator of array.array now conforms with the behavior of iterators of other mutable sequences: it lefts exhausted even if iterated array is extended.

bpo-26641 [https://bugs.python.org/issue?@action=redirect&bpo=26641]: doctest.DocFileTest and doctest.testfile() now support packages (module split into multiple directories) for the package parameter.

bpo-25195 [https://bugs.python.org/issue?@action=redirect&bpo=25195]: Fix a regression in mock.MagicMock. _Call is a subclass of tuple (changeset 3603bae63c13 only works for classes) so we need to implement __ne__ ourselves. Patch by Andrew Plummer.

bpo-26644 [https://bugs.python.org/issue?@action=redirect&bpo=26644]: Raise ValueError rather than SystemError when a negative length is passed to SSLSocket.recv() or read().

bpo-23804 [https://bugs.python.org/issue?@action=redirect&bpo=23804]: Fix SSL recv(0) and read(0) methods to return zero bytes instead of up to 1024.

bpo-26616 [https://bugs.python.org/issue?@action=redirect&bpo=26616]: Fixed a bug in datetime.astimezone() method.

bpo-26637 [https://bugs.python.org/issue?@action=redirect&bpo=26637]: The importlib module now emits an ImportError rather than a TypeError if __import__() is tried during the Python shutdown process but sys.path is already cleared (set to None).

bpo-21925 [https://bugs.python.org/issue?@action=redirect&bpo=21925]: warnings.formatwarning() now catches exceptions when calling linecache.getline() and tracemalloc.get_object_traceback() to be able to log ResourceWarning emitted late during the Python shutdown process.

bpo-23848 [https://bugs.python.org/issue?@action=redirect&bpo=23848]: On Windows, faulthandler.enable() now also installs an exception handler to dump the traceback of all Python threads on any Windows exception, not only on UNIX signals (SIGSEGV, SIGFPE, SIGABRT).

bpo-26530 [https://bugs.python.org/issue?@action=redirect&bpo=26530]: Add C functions _PyTraceMalloc_Track() and _PyTraceMalloc_Untrack() to track memory blocks using the tracemalloc module. Add _PyTraceMalloc_GetTraceback() to get the traceback of an object.

bpo-26588 [https://bugs.python.org/issue?@action=redirect&bpo=26588]: The _tracemalloc now supports tracing memory allocations of multiple address spaces (domains).

bpo-24266 [https://bugs.python.org/issue?@action=redirect&bpo=24266]: Ctrl+C during Readline history search now cancels the search mode when compiled with Readline 7.

bpo-26590 [https://bugs.python.org/issue?@action=redirect&bpo=26590]: Implement a safe finalizer for the _socket.socket type. It now releases the GIL to close the socket.

bpo-18787 [https://bugs.python.org/issue?@action=redirect&bpo=18787]: spwd.getspnam() now raises a PermissionError if the user doesn’t have privileges.

bpo-26560 [https://bugs.python.org/issue?@action=redirect&bpo=26560]: Avoid potential ValueError in BaseHandler.start_response. Initial patch by Peter Inglesby.

bpo-26567 [https://bugs.python.org/issue?@action=redirect&bpo=26567]: Add a new function PyErr_ResourceWarning() function to pass the destroyed object. Add a source attribute to warnings.WarningMessage. Add warnings._showwarnmsg() which uses tracemalloc to get the traceback where source object was allocated.

bpo-26569 [https://bugs.python.org/issue?@action=redirect&bpo=26569]: Fix pyclbr.readmodule() and pyclbr.readmodule_ex() to support importing packages.

bpo-26499 [https://bugs.python.org/issue?@action=redirect&bpo=26499]: Account for remaining Content-Length in HTTPResponse.readline() and read1(). Based on patch by Silent Ghost. Also document that HTTPResponse now supports these methods.

bpo-25320 [https://bugs.python.org/issue?@action=redirect&bpo=25320]: Handle sockets in directories unittest discovery is scanning. Patch from Victor van den Elzen.

bpo-16181 [https://bugs.python.org/issue?@action=redirect&bpo=16181]: cookiejar.http2time() now returns None if year is higher than datetime.MAXYEAR.

bpo-26513 [https://bugs.python.org/issue?@action=redirect&bpo=26513]: Fixes platform module detection of Windows Server

bpo-23718 [https://bugs.python.org/issue?@action=redirect&bpo=23718]: Fixed parsing time in week 0 before Jan 1. Original patch by Tamás Bence Gedai.

bpo-26323 [https://bugs.python.org/issue?@action=redirect&bpo=26323]: Add Mock.assert_called() and Mock.assert_called_once() methods to unittest.mock. Patch written by Amit Saha.

bpo-20589 [https://bugs.python.org/issue?@action=redirect&bpo=20589]: Invoking Path.owner() and Path.group() on Windows now raise NotImplementedError instead of ImportError.

bpo-26177 [https://bugs.python.org/issue?@action=redirect&bpo=26177]: Fixed the keys() method for Canvas and Scrollbar widgets.

bpo-15068 [https://bugs.python.org/issue?@action=redirect&bpo=15068]: Got rid of excessive buffering in fileinput. The bufsize parameter is now deprecated and ignored.

bpo-19475 [https://bugs.python.org/issue?@action=redirect&bpo=19475]: Added an optional argument timespec to the datetime isoformat() method to choose the precision of the time component.

bpo-2202 [https://bugs.python.org/issue?@action=redirect&bpo=2202]: Fix UnboundLocalError in AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by Mathieu Dupuy.

bpo-26167 [https://bugs.python.org/issue?@action=redirect&bpo=26167]: Minimized overhead in copy.copy() and copy.deepcopy(). Optimized copying and deepcopying bytearrays, NotImplemented, slices, short lists, tuples, dicts, sets.

bpo-25718 [https://bugs.python.org/issue?@action=redirect&bpo=25718]: Fixed pickling and copying the accumulate() iterator with total is None.

bpo-26475 [https://bugs.python.org/issue?@action=redirect&bpo=26475]: Fixed debugging output for regular expressions with the (?x) flag.

bpo-26482 [https://bugs.python.org/issue?@action=redirect&bpo=26482]: Allowed pickling recursive dequeues.

bpo-26335 [https://bugs.python.org/issue?@action=redirect&bpo=26335]: Make mmap.write() return the number of bytes written like other write methods. Patch by Jakub Stasiak.

bpo-26457 [https://bugs.python.org/issue?@action=redirect&bpo=26457]: Fixed the subnets() methods in IP network classes for the case when resulting prefix length is equal to maximal prefix length. Based on patch by Xiang Zhang.

bpo-26385 [https://bugs.python.org/issue?@action=redirect&bpo=26385]: Remove the file if the internal open() call in NamedTemporaryFile() fails. Patch by Silent Ghost.

bpo-26402 [https://bugs.python.org/issue?@action=redirect&bpo=26402]: Fix XML-RPC client to retry when the server shuts down a persistent connection. This was a regression related to the new http.client.RemoteDisconnected exception in 3.5.0a4.

bpo-25913 [https://bugs.python.org/issue?@action=redirect&bpo=25913]: Leading <~ is optional now in base64.a85decode() with adobe=True. Patch by Swati Jaiswal.

bpo-26186 [https://bugs.python.org/issue?@action=redirect&bpo=26186]: Remove an invalid type check in importlib.util.LazyLoader.

bpo-26367 [https://bugs.python.org/issue?@action=redirect&bpo=26367]: importlib.__import__() raises ImportError like builtins.__import__() when level is specified but without an accompanying package specified.

bpo-26309 [https://bugs.python.org/issue?@action=redirect&bpo=26309]: In the “socketserver” module, shut down the request (closing the connected socket) when verify_request() returns false. Patch by Aviv Palivoda.

bpo-23430 [https://bugs.python.org/issue?@action=redirect&bpo=23430]: Change the socketserver module to only catch exceptions raised from a request handler that are derived from Exception (instead of BaseException). Therefore SystemExit and KeyboardInterrupt no longer trigger the handle_error() method, and will now to stop a single-threaded server.

bpo-25995 [https://bugs.python.org/issue?@action=redirect&bpo=25995]: os.walk() no longer uses FDs proportional to the tree depth.

bpo-25994 [https://bugs.python.org/issue?@action=redirect&bpo=25994]: Added the close() method and the support of the context manager protocol for the os.scandir() iterator.

bpo-23992 [https://bugs.python.org/issue?@action=redirect&bpo=23992]: multiprocessing: make MapResult not fail-fast upon exception.

bpo-26243 [https://bugs.python.org/issue?@action=redirect&bpo=26243]: Support keyword arguments to zlib.compress(). Patch by Aviv Palivoda.

bpo-26117 [https://bugs.python.org/issue?@action=redirect&bpo=26117]: The os.scandir() iterator now closes file descriptor not only when the iteration is finished, but when it was failed with error.

bpo-25949 [https://bugs.python.org/issue?@action=redirect&bpo=25949]: __dict__ for an OrderedDict instance is now created only when needed.

bpo-25911 [https://bugs.python.org/issue?@action=redirect&bpo=25911]: Restored support of bytes paths in os.walk() on Windows.

bpo-26045 [https://bugs.python.org/issue?@action=redirect&bpo=26045]: Add UTF-8 suggestion to error message when posting a non-Latin-1 string with http.client.

bpo-26039 [https://bugs.python.org/issue?@action=redirect&bpo=26039]: Added zipfile.ZipInfo.from_file() and zipinfo.ZipInfo.is_dir(). Patch by Thomas Kluyver.

bpo-12923 [https://bugs.python.org/issue?@action=redirect&bpo=12923]: Reset FancyURLopener’s redirect counter even if there is an exception. Based on patches by Brian Brazil and Daniel Rocco.

bpo-25945 [https://bugs.python.org/issue?@action=redirect&bpo=25945]: Fixed a crash when unpickle the functools.partial object with wrong state. Fixed a leak in failed functools.partial constructor. “args” and “keywords” attributes of functools.partial have now always types tuple and dict correspondingly.

bpo-26202 [https://bugs.python.org/issue?@action=redirect&bpo=26202]: copy.deepcopy() now correctly copies range() objects with non-atomic attributes.

bpo-23076 [https://bugs.python.org/issue?@action=redirect&bpo=23076]: Path.glob() now raises a ValueError if it’s called with an invalid pattern. Patch by Thomas Nyberg.

bpo-19883 [https://bugs.python.org/issue?@action=redirect&bpo=19883]: Fixed possible integer overflows in zipimport.

bpo-26227 [https://bugs.python.org/issue?@action=redirect&bpo=26227]: On Windows, getnameinfo(), gethostbyaddr() and gethostbyname_ex() functions of the socket module now decode the hostname from the ANSI code page rather than UTF-8.

bpo-26099 [https://bugs.python.org/issue?@action=redirect&bpo=26099]: The site module now writes an error into stderr if sitecustomize module can be imported but executing the module raise an ImportError. Same change for usercustomize.

bpo-26147 [https://bugs.python.org/issue?@action=redirect&bpo=26147]: xmlrpc now works with strings not encodable with used non-UTF-8 encoding.

bpo-25935 [https://bugs.python.org/issue?@action=redirect&bpo=25935]: Garbage collector now breaks reference loops with OrderedDict.

bpo-16620 [https://bugs.python.org/issue?@action=redirect&bpo=16620]: Fixed AttributeError in msilib.Directory.glob().

bpo-26013 [https://bugs.python.org/issue?@action=redirect&bpo=26013]: Added compatibility with broken protocol 2 pickles created in old Python 3 versions (3.4.3 and lower).

bpo-26129 [https://bugs.python.org/issue?@action=redirect&bpo=26129]: Deprecated accepting non-integers in grp.getgrgid().

bpo-25850 [https://bugs.python.org/issue?@action=redirect&bpo=25850]: Use cross-compilation by default for 64-bit Windows.

bpo-25822 [https://bugs.python.org/issue?@action=redirect&bpo=25822]: Add docstrings to the fields of urllib.parse results. Patch contributed by Swati Jaiswal.

bpo-22642 [https://bugs.python.org/issue?@action=redirect&bpo=22642]: Convert trace module option parsing mechanism to argparse. Patch contributed by SilentGhost.

bpo-24705 [https://bugs.python.org/issue?@action=redirect&bpo=24705]: Fix sysconfig._parse_makefile not expanding ${} vars appearing before $() vars.

bpo-26069 [https://bugs.python.org/issue?@action=redirect&bpo=26069]: Remove the deprecated apis in the trace module.

bpo-22138 [https://bugs.python.org/issue?@action=redirect&bpo=22138]: Fix mock.patch behavior when patching descriptors. Restore original values after patching. Patch contributed by Sean McCully.

bpo-25672 [https://bugs.python.org/issue?@action=redirect&bpo=25672]: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS mode option if it is safe to do so.

bpo-26012 [https://bugs.python.org/issue?@action=redirect&bpo=26012]: Don’t traverse into symlinks for ** pattern in pathlib.Path.[r]glob().

bpo-24120 [https://bugs.python.org/issue?@action=redirect&bpo=24120]: Ignore PermissionError when traversing a tree with pathlib.Path.[r]glob(). Patch by Ulrich Petri.

bpo-21815 [https://bugs.python.org/issue?@action=redirect&bpo=21815]: Accept ] characters in the data portion of imap responses, in order to handle the flags with square brackets accepted and produced by servers such as gmail.

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: fileinput now uses sys.stdin as-is if it does not have a buffer attribute (restores backward compatibility).

bpo-25971 [https://bugs.python.org/issue?@action=redirect&bpo=25971]: Optimized creating Fractions from floats by 2 times and from Decimals by 3 times.

bpo-25802 [https://bugs.python.org/issue?@action=redirect&bpo=25802]: Document as deprecated the remaining implementations of importlib.abc.Loader.load_module().

bpo-25928 [https://bugs.python.org/issue?@action=redirect&bpo=25928]: Add Decimal.as_integer_ratio().

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: Copying the lru_cache() wrapper object now always works, independently from the type of the wrapped object (by returning the original object unchanged).

bpo-25768 [https://bugs.python.org/issue?@action=redirect&bpo=25768]: Have the functions in compileall return booleans instead of ints and add proper documentation and tests for the return values.

bpo-24103 [https://bugs.python.org/issue?@action=redirect&bpo=24103]: Fixed possible use after free in ElementTree.XMLPullParser.

bpo-25860 [https://bugs.python.org/issue?@action=redirect&bpo=25860]: os.fwalk() no longer skips remaining directories when error occurs. Original patch by Samson Lee.

bpo-25914 [https://bugs.python.org/issue?@action=redirect&bpo=25914]: Fixed and simplified OrderedDict.__sizeof__.

bpo-25869 [https://bugs.python.org/issue?@action=redirect&bpo=25869]: Optimized deepcopying ElementTree; it is now 20 times faster.

bpo-25873 [https://bugs.python.org/issue?@action=redirect&bpo=25873]: Optimized iterating ElementTree. Iterating elements Element.iter() is now 40% faster, iterating text Element.itertext() is now up to 2.5 times faster.

bpo-25902 [https://bugs.python.org/issue?@action=redirect&bpo=25902]: Fixed various refcount issues in ElementTree iteration.

bpo-22227 [https://bugs.python.org/issue?@action=redirect&bpo=22227]: The TarFile iterator is reimplemented using generator. This implementation is simpler that using class.

bpo-25638 [https://bugs.python.org/issue?@action=redirect&bpo=25638]: Optimized ElementTree.iterparse(); it is now 2x faster. Optimized ElementTree parsing; it is now 10% faster.

bpo-25761 [https://bugs.python.org/issue?@action=redirect&bpo=25761]: Improved detecting errors in broken pickle data.

bpo-25717 [https://bugs.python.org/issue?@action=redirect&bpo=25717]: Restore the previous behaviour of tolerating most fstat() errors when opening files. This was a regression in 3.5a1, and stopped anonymous temporary files from working in special cases.

bpo-24903 [https://bugs.python.org/issue?@action=redirect&bpo=24903]: Fix regression in number of arguments compileall accepts when ‘-d’ is specified. The check on the number of arguments has been dropped completely as it never worked correctly anyway.

bpo-25764 [https://bugs.python.org/issue?@action=redirect&bpo=25764]: In the subprocess module, preserve any exception caused by fork() failure when preexec_fn is used.

bpo-25771 [https://bugs.python.org/issue?@action=redirect&bpo=25771]: Tweak the exception message for importlib.util.resolve_name() when ‘package’ isn’t specified but necessary.

bpo-6478 [https://bugs.python.org/issue?@action=redirect&bpo=6478]: _strptime’s regexp cache now is reset after changing timezone with time.tzset().

bpo-14285 [https://bugs.python.org/issue?@action=redirect&bpo=14285]: When executing a package with the “python -m package” option, and package initialization fails, a proper traceback is now reported. The “runpy” module now lets exceptions from package initialization pass back to the caller, rather than raising ImportError.

bpo-19771 [https://bugs.python.org/issue?@action=redirect&bpo=19771]: Also in runpy and the “-m” option, omit the irrelevant message “… is a package and cannot be directly executed” if the package could not even be initialized (e.g. due to a bad *.pyc file).

bpo-25177 [https://bugs.python.org/issue?@action=redirect&bpo=25177]: Fixed problem with the mean of very small and very large numbers. As a side effect, statistics.mean and statistics.variance should be significantly faster.

bpo-25718 [https://bugs.python.org/issue?@action=redirect&bpo=25718]: Fixed copying object with state with boolean value is false.

bpo-10131 [https://bugs.python.org/issue?@action=redirect&bpo=10131]: Fixed deep copying of minidom documents. Based on patch by Marian Ganisin.

bpo-7990 [https://bugs.python.org/issue?@action=redirect&bpo=7990]: dir() on ElementTree.Element now lists properties: “tag”, “text”, “tail” and “attrib”. Original patch by Santoso Wijaya.

bpo-25725 [https://bugs.python.org/issue?@action=redirect&bpo=25725]: Fixed a reference leak in pickle.loads() when unpickling invalid data including tuple instructions.

bpo-25663 [https://bugs.python.org/issue?@action=redirect&bpo=25663]: In the Readline completer, avoid listing duplicate global names, and search the global namespace before searching builtins.

bpo-25688 [https://bugs.python.org/issue?@action=redirect&bpo=25688]: Fixed file leak in ElementTree.iterparse() raising an error.

bpo-23914 [https://bugs.python.org/issue?@action=redirect&bpo=23914]: Fixed SystemError raised by unpickler on broken pickle data.

bpo-25691 [https://bugs.python.org/issue?@action=redirect&bpo=25691]: Fixed crash on deleting ElementTree.Element attributes.

bpo-25624 [https://bugs.python.org/issue?@action=redirect&bpo=25624]: ZipFile now always writes a ZIP_STORED header for directory entries. Patch by Dingyuan Wang.

bpo-25626 [https://bugs.python.org/issue?@action=redirect&bpo=25626]: Change three zlib functions to accept sizes that fit in Py_ssize_t, but internally cap those sizes to UINT_MAX. This resolves a regression in 3.5 where GzipFile.read() failed to read chunks larger than 2 or 4 GiB. The change affects the zlib.Decompress.decompress() max_length parameter, the zlib.decompress() bufsize parameter, and the zlib.Decompress.flush() length parameter.

bpo-25583 [https://bugs.python.org/issue?@action=redirect&bpo=25583]: Avoid incorrect errors raised by os.makedirs(exist_ok=True) when the OS gives priority to errors such as EACCES over EEXIST.

bpo-25593 [https://bugs.python.org/issue?@action=redirect&bpo=25593]: Change semantics of EventLoop.stop() in asyncio.

bpo-6973 [https://bugs.python.org/issue?@action=redirect&bpo=6973]: When we know a subprocess.Popen process has died, do not allow the send_signal(), terminate(), or kill() methods to do anything as they could potentially signal a different process.

bpo-23883 [https://bugs.python.org/issue?@action=redirect&bpo=23883]: Added missing APIs to __all__ to match the documented APIs for the following modules: calendar, csv, enum, fileinput, ftplib, logging, optparse, tarfile, threading and wave. Also added a test.support.check__all__() helper. Patches by Jacek Kołodziej, Mauro S. M. Rodrigues and Joel Taddei.

bpo-25590 [https://bugs.python.org/issue?@action=redirect&bpo=25590]: In the Readline completer, only call getattr() once per attribute. Also complete names of attributes such as properties and slots which are listed by dir() but not yet created on an instance.

bpo-25498 [https://bugs.python.org/issue?@action=redirect&bpo=25498]: Fix a crash when garbage-collecting ctypes objects created by wrapping a memoryview. This was a regression made in 3.5a1. Based on patch by Eryksun.

bpo-25584 [https://bugs.python.org/issue?@action=redirect&bpo=25584]: Added “escape” to the __all__ list in the glob module.

bpo-25584 [https://bugs.python.org/issue?@action=redirect&bpo=25584]: Fixed recursive glob() with patterns starting with **.

bpo-25446 [https://bugs.python.org/issue?@action=redirect&bpo=25446]: Fix regression in smtplib’s AUTH LOGIN support.

bpo-18010 [https://bugs.python.org/issue?@action=redirect&bpo=18010]: Fix the pydoc web server’s module search function to handle exceptions from importing packages.

bpo-25554 [https://bugs.python.org/issue?@action=redirect&bpo=25554]: Got rid of circular references in regular expression parsing.

bpo-18973 [https://bugs.python.org/issue?@action=redirect&bpo=18973]: Command-line interface of the calendar module now uses argparse instead of optparse.

bpo-25510 [https://bugs.python.org/issue?@action=redirect&bpo=25510]: fileinput.FileInput.readline() now returns b’’ instead of ‘’ at the end if the FileInput was opened with binary mode. Patch by Ryosuke Ito.

bpo-25503 [https://bugs.python.org/issue?@action=redirect&bpo=25503]: Fixed inspect.getdoc() for inherited docstrings of properties. Original patch by John Mark Vandenberg.

bpo-25515 [https://bugs.python.org/issue?@action=redirect&bpo=25515]: Always use os.urandom as a source of randomness in uuid.uuid4.

bpo-21827 [https://bugs.python.org/issue?@action=redirect&bpo=21827]: Fixed textwrap.dedent() for the case when largest common whitespace is a substring of smallest leading whitespace. Based on patch by Robert Li.

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: The lru_cache() wrapper objects now can be copied and pickled (by returning the original object unchanged).

bpo-25390 [https://bugs.python.org/issue?@action=redirect&bpo=25390]: typing: Don’t crash on Union[str, Pattern].

bpo-25441 [https://bugs.python.org/issue?@action=redirect&bpo=25441]: asyncio: Raise error from drain() when socket is closed.

bpo-25410 [https://bugs.python.org/issue?@action=redirect&bpo=25410]: Cleaned up and fixed minor bugs in C implementation of OrderedDict.

bpo-25411 [https://bugs.python.org/issue?@action=redirect&bpo=25411]: Improved Unicode support in SMTPHandler through better use of the email package. Thanks to user simon04 for the patch.

Move the imp module from a PendingDeprecationWarning to DeprecationWarning.

bpo-25407 [https://bugs.python.org/issue?@action=redirect&bpo=25407]: Remove mentions of the formatter module being removed in Python 3.6.

bpo-25406 [https://bugs.python.org/issue?@action=redirect&bpo=25406]: Fixed a bug in C implementation of OrderedDict.move_to_end() that caused segmentation fault or hang in iterating after moving several items to the start of ordered dict.

bpo-25382 [https://bugs.python.org/issue?@action=redirect&bpo=25382]: pickletools.dis() now outputs implicit memo index for the MEMOIZE opcode.

bpo-25357 [https://bugs.python.org/issue?@action=redirect&bpo=25357]: Add an optional newline parameter to binascii.b2a_base64(). base64.b64encode() uses it to avoid a memory copy.

bpo-24164 [https://bugs.python.org/issue?@action=redirect&bpo=24164]: Objects that need calling __new__ with keyword arguments, can now be pickled using pickle protocols older than protocol version 4.

bpo-25364 [https://bugs.python.org/issue?@action=redirect&bpo=25364]: zipfile now works in threads disabled builds.

bpo-25328 [https://bugs.python.org/issue?@action=redirect&bpo=25328]: smtpd’s SMTPChannel now correctly raises a ValueError if both decode_data and enable_SMTPUTF8 are set to true.

bpo-16099 [https://bugs.python.org/issue?@action=redirect&bpo=16099]: RobotFileParser now supports Crawl-delay and Request-rate extensions. Patch by Nikolay Bogoychev.

bpo-25316 [https://bugs.python.org/issue?@action=redirect&bpo=25316]: distutils raises OSError instead of DistutilsPlatformError when MSVC is not installed.

bpo-25380 [https://bugs.python.org/issue?@action=redirect&bpo=25380]: Fixed protocol for the STACK_GLOBAL opcode in pickletools.opcodes.

bpo-23972 [https://bugs.python.org/issue?@action=redirect&bpo=23972]: Updates asyncio datagram create method allowing reuseport and reuseaddr socket options to be set prior to binding the socket. Mirroring the existing asyncio create_server method the reuseaddr option for datagram sockets defaults to True if the O/S is ‘posix’ (except if the platform is Cygwin). Patch by Chris Laws.

bpo-25304 [https://bugs.python.org/issue?@action=redirect&bpo=25304]: Add asyncio.run_coroutine_threadsafe(). This lets you submit a coroutine to a loop from another thread, returning a concurrent.futures.Future. By Vincent Michel.

bpo-25232 [https://bugs.python.org/issue?@action=redirect&bpo=25232]: Fix CGIRequestHandler to split the query from the URL at the first question mark (?) rather than the last. Patch from Xiang Zhang.

bpo-24657 [https://bugs.python.org/issue?@action=redirect&bpo=24657]: Prevent CGIRequestHandler from collapsing slashes in the query part of the URL as if it were a path. Patch from Xiang Zhang.

bpo-25287 [https://bugs.python.org/issue?@action=redirect&bpo=25287]: Don’t add crypt.METHOD_CRYPT to crypt.methods if it’s not supported. Check if it is supported, it may not be supported on OpenBSD for example.

bpo-23600 [https://bugs.python.org/issue?@action=redirect&bpo=23600]: Default implementation of tzinfo.fromutc() was returning wrong results in some cases.

bpo-25203 [https://bugs.python.org/issue?@action=redirect&bpo=25203]: Failed readline.set_completer_delims() no longer left the module in inconsistent state.

bpo-25011 [https://bugs.python.org/issue?@action=redirect&bpo=25011]: rlcompleter now omits private and special attribute names unless the prefix starts with underscores.

bpo-25209 [https://bugs.python.org/issue?@action=redirect&bpo=25209]: rlcompleter now can add a space or a colon after completed keyword.

bpo-22241 [https://bugs.python.org/issue?@action=redirect&bpo=22241]: timezone.utc name is now plain ‘UTC’, not ‘UTC-00:00’.

bpo-23517 [https://bugs.python.org/issue?@action=redirect&bpo=23517]: fromtimestamp() and utcfromtimestamp() methods of datetime.datetime now round microseconds to nearest with ties going to nearest even integer (ROUND_HALF_EVEN), as round(float), instead of rounding towards -Infinity (ROUND_FLOOR).

bpo-23552 [https://bugs.python.org/issue?@action=redirect&bpo=23552]: Timeit now warns when there is substantial (4x) variance between best and worst times. Patch from Serhiy Storchaka.

bpo-24633 [https://bugs.python.org/issue?@action=redirect&bpo=24633]: site-packages/README -> README.txt.

bpo-24879 [https://bugs.python.org/issue?@action=redirect&bpo=24879]: help() and pydoc can now list named tuple fields in the order they were defined rather than alphabetically. The ordering is determined by the _fields attribute if present.

bpo-24874 [https://bugs.python.org/issue?@action=redirect&bpo=24874]: Improve speed of itertools.cycle() and make its pickle more compact.

Fix crash in itertools.cycle.__setstate__() when the first argument wasn’t a list.

bpo-20059 [https://bugs.python.org/issue?@action=redirect&bpo=20059]: urllib.parse raises ValueError on all invalid ports. Patch by Martin Panter.

bpo-24360 [https://bugs.python.org/issue?@action=redirect&bpo=24360]: Improve __repr__ of argparse.Namespace() for invalid identifiers. Patch by Matthias Bussonnier.

bpo-23426 [https://bugs.python.org/issue?@action=redirect&bpo=23426]: run_setup was broken in distutils. Patch from Alexander Belopolsky.

bpo-13938 [https://bugs.python.org/issue?@action=redirect&bpo=13938]: 2to3 converts StringTypes to a tuple. Patch from Mark Hammond.

bpo-2091 [https://bugs.python.org/issue?@action=redirect&bpo=2091]: open() accepted a ‘U’ mode string containing ‘+’, but ‘U’ can only be used with ‘r’. Patch from Jeff Balogh and John O’Connor.

bpo-8585 [https://bugs.python.org/issue?@action=redirect&bpo=8585]: improved tests for zipimporter2. Patch from Mark Lawrence.

bpo-18622 [https://bugs.python.org/issue?@action=redirect&bpo=18622]: unittest.mock.mock_open().reset_mock would recurse infinitely. Patch from Nicola Palumbo and Laurent De Buyst.

bpo-24426 [https://bugs.python.org/issue?@action=redirect&bpo=24426]: Fast searching optimization in regular expressions now works for patterns that starts with capturing groups. Fast searching optimization now can’t be disabled at compile time.

bpo-23661 [https://bugs.python.org/issue?@action=redirect&bpo=23661]: unittest.mock side_effects can now be exceptions again. This was a regression vs Python 3.4. Patch from Ignacio Rossi

bpo-13248 [https://bugs.python.org/issue?@action=redirect&bpo=13248]: Remove deprecated inspect.getmoduleinfo function.

bpo-25578 [https://bugs.python.org/issue?@action=redirect&bpo=25578]: Fix (another) memory leak in SSLSocket.getpeercer().

bpo-25530 [https://bugs.python.org/issue?@action=redirect&bpo=25530]: Disable the vulnerable SSLv3 protocol by default when creating ssl.SSLContext.

bpo-25569 [https://bugs.python.org/issue?@action=redirect&bpo=25569]: Fix memory leak in SSLSocket.getpeercert().

bpo-25471 [https://bugs.python.org/issue?@action=redirect&bpo=25471]: Sockets returned from accept() shouldn’t appear to be nonblocking.

bpo-25319 [https://bugs.python.org/issue?@action=redirect&bpo=25319]: When threading.Event is reinitialized, the underlying condition should use a regular lock rather than a recursive lock.

Skip getaddrinfo if host is already resolved. Patch by A. Jesse Jiryu Davis.

bpo-26050 [https://bugs.python.org/issue?@action=redirect&bpo=26050]: Add asyncio.StreamReader.readuntil() method. Patch by Марк Коренберг.

bpo-25924 [https://bugs.python.org/issue?@action=redirect&bpo=25924]: Avoid unnecessary serialization of getaddrinfo(3) calls on OS X versions 10.5 or higher. Original patch by A. Jesse Jiryu Davis.

bpo-26406 [https://bugs.python.org/issue?@action=redirect&bpo=26406]: Avoid unnecessary serialization of getaddrinfo(3) calls on current versions of OpenBSD and NetBSD. Patch by A. Jesse Jiryu Davis.

bpo-26848 [https://bugs.python.org/issue?@action=redirect&bpo=26848]: Fix asyncio/subprocess.communicate() to handle empty input. Patch by Jack O’Connor.

bpo-27040 [https://bugs.python.org/issue?@action=redirect&bpo=27040]: Add loop.get_exception_handler method

bpo-27041 [https://bugs.python.org/issue?@action=redirect&bpo=27041]: asyncio: Add loop.create_future method

IDLE

bpo-20640 [https://bugs.python.org/issue?@action=redirect&bpo=20640]: Add tests for idlelib.configHelpSourceEdit. Patch by Saimadhav Heblikar.

In the ‘IDLE-console differences’ section of the IDLE doc, clarify how running with IDLE affects sys.modules and the standard streams.

bpo-25507 [https://bugs.python.org/issue?@action=redirect&bpo=25507]: fix incorrect change in IOBinding that prevented printing. Augment IOBinding htest to include all major IOBinding functions.

bpo-25905 [https://bugs.python.org/issue?@action=redirect&bpo=25905]: Revert unwanted conversion of ‘ to ’ RIGHT SINGLE QUOTATION MARK in README.txt and open this and NEWS.txt with ‘ascii’. Re-encode CREDITS.txt to utf-8 and open it with ‘utf-8’.

bpo-15348 [https://bugs.python.org/issue?@action=redirect&bpo=15348]: Stop the debugger engine (normally in a user process) before closing the debugger window (running in the IDLE process). This prevents the RuntimeErrors that were being caught and ignored.

bpo-24455 [https://bugs.python.org/issue?@action=redirect&bpo=24455]: Prevent IDLE from hanging when a) closing the shell while the debugger is active (15347); b) closing the debugger with the [X] button (15348); and c) activating the debugger when already active (24455). The patch by Mark Roseman does this by making two changes. 1. Suspend and resume the gui.interaction method with the tcl vwait mechanism intended for this purpose (instead of root.mainloop & .quit). 2. In gui.run, allow any existing interaction to terminate first.

Change ‘The program’ to ‘Your program’ in an IDLE ‘kill program?’ message to make it clearer that the program referred to is the currently running user program, not IDLE itself.

bpo-24750 [https://bugs.python.org/issue?@action=redirect&bpo=24750]: Improve the appearance of the IDLE editor window status bar. Patch by Mark Roseman.

bpo-25313 [https://bugs.python.org/issue?@action=redirect&bpo=25313]: Change the handling of new built-in text color themes to better address the compatibility problem introduced by the addition of IDLE Dark. Consistently use the revised idleConf.CurrentTheme everywhere in idlelib.

bpo-24782 [https://bugs.python.org/issue?@action=redirect&bpo=24782]: Extension configuration is now a tab in the IDLE Preferences dialog rather than a separate dialog. The former tabs are now a sorted list. Patch by Mark Roseman.

bpo-22726 [https://bugs.python.org/issue?@action=redirect&bpo=22726]: Re-activate the config dialog help button with some content about the other buttons and the new IDLE Dark theme.

bpo-24820 [https://bugs.python.org/issue?@action=redirect&bpo=24820]: IDLE now has an ‘IDLE Dark’ built-in text color theme. It is more or less IDLE Classic inverted, with a cobalt blue background. Strings, comments, keywords, … are still green, red, orange, … . To use it with IDLEs released before November 2015, hit the ‘Save as New Custom Theme’ button and enter a new name, such as ‘Custom Dark’. The custom theme will work with any IDLE release, and can be modified.

bpo-25224 [https://bugs.python.org/issue?@action=redirect&bpo=25224]: README.txt is now an idlelib index for IDLE developers and curious users. The previous user content is now in the IDLE doc chapter. ‘IDLE’ now means ‘Integrated Development and Learning Environment’.

bpo-24820 [https://bugs.python.org/issue?@action=redirect&bpo=24820]: Users can now set breakpoint colors in Settings -> Custom Highlighting. Original patch by Mark Roseman.

bpo-24972 [https://bugs.python.org/issue?@action=redirect&bpo=24972]: Inactive selection background now matches active selection background, as configured by users, on all systems. Found items are now always highlighted on Windows. Initial patch by Mark Roseman.

bpo-24570 [https://bugs.python.org/issue?@action=redirect&bpo=24570]: Idle: make calltip and completion boxes appear on Macs affected by a tk regression. Initial patch by Mark Roseman.

bpo-24988 [https://bugs.python.org/issue?@action=redirect&bpo=24988]: Idle ScrolledList context menus (used in debugger) now work on Mac Aqua. Patch by Mark Roseman.

bpo-24801 [https://bugs.python.org/issue?@action=redirect&bpo=24801]: Make right-click for context menu work on Mac Aqua. Patch by Mark Roseman.

bpo-25173 [https://bugs.python.org/issue?@action=redirect&bpo=25173]: Associate tkinter messageboxes with a specific widget. For Mac OSX, make them a ‘sheet’. Patch by Mark Roseman.

bpo-25198 [https://bugs.python.org/issue?@action=redirect&bpo=25198]: Enhance the initial html viewer now used for Idle Help. Properly indent fixed-pitch text (patch by Mark Roseman). Give code snippet a very Sphinx-like light blueish-gray background. Re-use initial width and height set by users for shell and editor. When the Table of Contents (TOC) menu is used, put the section header at the top of the screen.

bpo-25225 [https://bugs.python.org/issue?@action=redirect&bpo=25225]: Condense and rewrite Idle doc section on text colors.

bpo-21995 [https://bugs.python.org/issue?@action=redirect&bpo=21995]: Explain some differences between IDLE and console Python.

bpo-22820 [https://bugs.python.org/issue?@action=redirect&bpo=22820]: Explain need for print when running file from Idle editor.

bpo-25224 [https://bugs.python.org/issue?@action=redirect&bpo=25224]: Doc: augment Idle feature list and no-subprocess section.

bpo-25219 [https://bugs.python.org/issue?@action=redirect&bpo=25219]: Update doc for Idle command line options. Some were missing and notes were not correct.

bpo-24861 [https://bugs.python.org/issue?@action=redirect&bpo=24861]: Most of idlelib is private and subject to change. Use idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

bpo-25199 [https://bugs.python.org/issue?@action=redirect&bpo=25199]: Idle: add synchronization comments for future maintainers.

bpo-16893 [https://bugs.python.org/issue?@action=redirect&bpo=16893]: Replace help.txt with help.html for Idle doc display. The new idlelib/help.html is rstripped Doc/build/html/library/idle.html. It looks better than help.txt and will better document Idle as released. The tkinter html viewer that works for this file was written by Rose Roseman. The now unused EditorWindow.HelpDialog class and helt.txt file are deprecated.

bpo-24199 [https://bugs.python.org/issue?@action=redirect&bpo=24199]: Deprecate unused idlelib.idlever with possible removal in 3.6.

bpo-24790 [https://bugs.python.org/issue?@action=redirect&bpo=24790]: Remove extraneous code (which also create 2 & 3 conflicts).

Documentation

bpo-26736 [https://bugs.python.org/issue?@action=redirect&bpo=26736]: Used HTTPS for external links in the documentation if possible.

bpo-6953 [https://bugs.python.org/issue?@action=redirect&bpo=6953]: Rework the Readline module documentation to group related functions together, and add more details such as what underlying Readline functions and variables are accessed.

bpo-23606 [https://bugs.python.org/issue?@action=redirect&bpo=23606]: Adds note to ctypes documentation regarding cdll.msvcrt.

bpo-24952 [https://bugs.python.org/issue?@action=redirect&bpo=24952]: Clarify the default size argument of stack_size() in the “threading” and “_thread” modules. Patch from Mattip.

bpo-26014 [https://bugs.python.org/issue?@action=redirect&bpo=26014]: Update 3.x packaging documentation: * “See also” links to the new docs are now provided in the legacy pages * links to setuptools documentation have been updated

Tests

bpo-21916 [https://bugs.python.org/issue?@action=redirect&bpo=21916]: Added tests for the turtle module. Patch by ingrid, Gregory Loyse and Jelle Zijlstra.

bpo-26295 [https://bugs.python.org/issue?@action=redirect&bpo=26295]: When using “python3 -m test –testdir=TESTDIR”, regrtest doesn’t add “test.” prefix to test module names.

bpo-26523 [https://bugs.python.org/issue?@action=redirect&bpo=26523]: The multiprocessing thread pool (multiprocessing.dummy.Pool) was untested.

bpo-26015 [https://bugs.python.org/issue?@action=redirect&bpo=26015]: Added new tests for pickling iterators of mutable sequences.

bpo-26325 [https://bugs.python.org/issue?@action=redirect&bpo=26325]: Added test.support.check_no_resource_warning() to check that no ResourceWarning is emitted.

bpo-25940 [https://bugs.python.org/issue?@action=redirect&bpo=25940]: Changed test_ssl to use its internal local server more. This avoids relying on svn.python.org, which recently changed root certificate.

bpo-25616 [https://bugs.python.org/issue?@action=redirect&bpo=25616]: Tests for OrderedDict are extracted from test_collections into separate file test_ordered_dict.

bpo-25449 [https://bugs.python.org/issue?@action=redirect&bpo=25449]: Added tests for OrderedDict subclasses.

bpo-25188 [https://bugs.python.org/issue?@action=redirect&bpo=25188]: Add -P/–pgo to test.regrtest to suppress error output when running the test suite for the purposes of a PGO build. Initial patch by Alecsandru Patrascu.

bpo-22806 [https://bugs.python.org/issue?@action=redirect&bpo=22806]: Add python -m test --list-tests command to list tests.

bpo-18174 [https://bugs.python.org/issue?@action=redirect&bpo=18174]: python -m test --huntrleaks ... now also checks for leak of file descriptors. Patch written by Richard Oudkerk.

bpo-25260 [https://bugs.python.org/issue?@action=redirect&bpo=25260]: Fix python -m test --coverage on Windows. Remove the list of ignored directories.

PCbuild\rt.bat now accepts an unlimited number of arguments to pass along to regrtest.py. Previously there was a limit of 9.

bpo-26583 [https://bugs.python.org/issue?@action=redirect&bpo=26583]: Skip test_timestamp_overflow in test_import if bytecode files cannot be written.

Build

bpo-21277 [https://bugs.python.org/issue?@action=redirect&bpo=21277]: Don’t try to link _ctypes with a ffi_convenience library.

bpo-26884 [https://bugs.python.org/issue?@action=redirect&bpo=26884]: Fix linking extension modules for cross builds. Patch by Xavier de Gaye.

bpo-26932 [https://bugs.python.org/issue?@action=redirect&bpo=26932]: Fixed support of RTLD_* constants defined as enum values, not via macros (in particular on Android). Patch by Chi Hsuan Yen.

bpo-22359 [https://bugs.python.org/issue?@action=redirect&bpo=22359]: Disable the rules for running _freeze_importlib and pgen when cross-compiling. The output of these programs is normally saved with the source code anyway, and is still regenerated when doing a native build. Patch by Xavier de Gaye.

bpo-21668 [https://bugs.python.org/issue?@action=redirect&bpo=21668]: Link audioop, _datetime, _ctypes_test modules to libm, except on Mac OS X. Patch written by Chi Hsuan Yen.

bpo-25702 [https://bugs.python.org/issue?@action=redirect&bpo=25702]: A –with-lto configure option has been added that will enable link time optimizations at build time during a make profile-opt. Some compilers and toolchains are known to not produce stable code when using LTO, be sure to test things thoroughly before relying on it. It can provide a few % speed up over profile-opt alone.

bpo-26624 [https://bugs.python.org/issue?@action=redirect&bpo=26624]: Adds validation of ucrtbase[d].dll version with warning for old versions.

bpo-17603 [https://bugs.python.org/issue?@action=redirect&bpo=17603]: Avoid error about nonexistent fileblocks.o file by using a lower-level check for st_blocks in struct stat.

bpo-26079 [https://bugs.python.org/issue?@action=redirect&bpo=26079]: Fixing the build output folder for tix-8.4.3.6. Patch by Bjoern Thiel.

bpo-26465 [https://bugs.python.org/issue?@action=redirect&bpo=26465]: Update Windows builds to use OpenSSL 1.0.2g.

bpo-25348 [https://bugs.python.org/issue?@action=redirect&bpo=25348]: Added --pgo and --pgo-job arguments to PCbuild\build.bat for building with Profile-Guided Optimization. The old PCbuild\build_pgo.bat script is removed.

bpo-25827 [https://bugs.python.org/issue?@action=redirect&bpo=25827]: Add support for building with ICC to configure, including a new --with-icc flag.

bpo-25696 [https://bugs.python.org/issue?@action=redirect&bpo=25696]: Fix installation of Python on UNIX with make -j9.

bpo-24986 [https://bugs.python.org/issue?@action=redirect&bpo=24986]: It is now possible to build Python on Windows without errors when external libraries are not available.

bpo-24421 [https://bugs.python.org/issue?@action=redirect&bpo=24421]: Compile Modules/_math.c once, before building extensions. Previously it could fail to compile properly if the math and cmath builds were concurrent.

bpo-26465 [https://bugs.python.org/issue?@action=redirect&bpo=26465]: Update OS X 10.5+ 32-bit-only installer to build and link with OpenSSL 1.0.2g.

bpo-26268 [https://bugs.python.org/issue?@action=redirect&bpo=26268]: Update Windows builds to use OpenSSL 1.0.2f.

bpo-25136 [https://bugs.python.org/issue?@action=redirect&bpo=25136]: Support Apple Xcode 7’s new textual SDK stub libraries.

bpo-24324 [https://bugs.python.org/issue?@action=redirect&bpo=24324]: Do not enable unreachable code warnings when using gcc as the option does not work correctly in older versions of gcc and has been silently removed as of gcc-4.5.

Windows

bpo-27053 [https://bugs.python.org/issue?@action=redirect&bpo=27053]: Updates make_zip.py to correctly generate library ZIP file.

bpo-26268 [https://bugs.python.org/issue?@action=redirect&bpo=26268]: Update the prepare_ssl.py script to handle OpenSSL releases that don’t include the contents of the include directory (that is, 1.0.2e and later).

bpo-26071 [https://bugs.python.org/issue?@action=redirect&bpo=26071]: bdist_wininst created binaries fail to start and find 32bit Python

bpo-26073 [https://bugs.python.org/issue?@action=redirect&bpo=26073]: Update the list of magic numbers in launcher

bpo-26065 [https://bugs.python.org/issue?@action=redirect&bpo=26065]: Excludes venv from library when generating embeddable distro.

bpo-25022 [https://bugs.python.org/issue?@action=redirect&bpo=25022]: Removed very outdated PC/example_nt/ directory.

Tools/Demos

bpo-26799 [https://bugs.python.org/issue?@action=redirect&bpo=26799]: Fix python-gdb.py: don’t get C types once when the Python code is loaded, but get C types on demand. The C types can change if python-gdb.py is loaded before the Python executable. Patch written by Thomas Ilsche.

bpo-26271 [https://bugs.python.org/issue?@action=redirect&bpo=26271]: Fix the Freeze tool to properly use flags passed through configure. Patch by Daniel Shaulov.

bpo-26489 [https://bugs.python.org/issue?@action=redirect&bpo=26489]: Add dictionary unpacking support to Tools/parser/unparse.py. Patch by Guo Ci Teo.

bpo-26316 [https://bugs.python.org/issue?@action=redirect&bpo=26316]: Fix variable name typo in Argument Clinic.

bpo-25440 [https://bugs.python.org/issue?@action=redirect&bpo=25440]: Fix output of python-config –extension-suffix.

bpo-25154 [https://bugs.python.org/issue?@action=redirect&bpo=25154]: The pyvenv script has been deprecated in favour of python3 -m venv.

C API

bpo-26312 [https://bugs.python.org/issue?@action=redirect&bpo=26312]: SystemError is now raised in all programming bugs with using PyArg_ParseTupleAndKeywords(). RuntimeError did raised before in some programming bugs.

bpo-26198 [https://bugs.python.org/issue?@action=redirect&bpo=26198]: ValueError is now raised instead of TypeError on buffer overflow in parsing “es#” and “et#” format units. SystemError is now raised instead of TypeError on programmatical error in parsing format string.

Python 3.5.5 final

Release date: 2018-02-04

There were no new changes in version 3.5.5.

Python 3.5.5 release candidate 1

Release date: 2018-01-23

Security

bpo-32551 [https://bugs.python.org/issue?@action=redirect&bpo=32551]: The sys.path[0] initialization change for bpo-29139 [https://bugs.python.org/issue?@action=redirect&bpo=29139] caused a regression by revealing an inconsistency in how sys.path is initialized when executing __main__ from a zipfile, directory, or other import location. This is considered a potential security issue, as it may lead to privileged processes unexpectedly loading code from user controlled directories in situations where that was not previously the case. The interpreter now consistently avoids ever adding the import location’s parent directory to sys.path, and ensures no other sys.path entries are inadvertently modified when inserting the import location named on the command line. (Originally reported as bpo-29723 [https://bugs.python.org/issue?@action=redirect&bpo=29723] against Python 3.6rc1, but it was missed at the time that the then upcoming Python 3.5.4 release would also be affected)

bpo-30657 [https://bugs.python.org/issue?@action=redirect&bpo=30657]: Fixed possible integer overflow in PyBytes_DecodeEscape, CVE 2017-1000158 [https://www.cve.org/CVERecord?id=CVE-2017-1000158]. Original patch by Jay Bosamiya; rebased to Python 3 by Miro Hrončok.

bpo-30947 [https://bugs.python.org/issue?@action=redirect&bpo=30947]: Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to get security fixes.

Core and Builtins

bpo-31095 [https://bugs.python.org/issue?@action=redirect&bpo=31095]: Fix potential crash during GC caused by tp_dealloc which doesn’t call PyObject_GC_UnTrack().

Library

bpo-32072 [https://bugs.python.org/issue?@action=redirect&bpo=32072]: Fixed issues with binary plists: Fixed saving bytearrays. Identical objects will be saved only once. Equal references will be load as identical objects. Added support for saving and loading recursive data structures.

bpo-31170 [https://bugs.python.org/issue?@action=redirect&bpo=31170]: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying of partial characters for UTF-8 input (libexpat bug 115): https://github.com/libexpat/libexpat/issues/115

Python 3.5.4 final

Release date: 2017-08-07

Library

bpo-30119 [https://bugs.python.org/issue?@action=redirect&bpo=30119]: ftplib.FTP.putline() now throws ValueError on commands that contains CR or LF. Patch by Donghee Na.

Python 3.5.4 release candidate 1

Release date: 2017-07-23

Security

bpo-30730 [https://bugs.python.org/issue?@action=redirect&bpo=30730]: Prevent environment variables injection in subprocess on Windows. Prevent passing other environment variables and command arguments.

bpo-30694 [https://bugs.python.org/issue?@action=redirect&bpo=30694]: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of multiple security vulnerabilities including: CVE 2017-9233 [https://www.cve.org/CVERecord?id=CVE-2017-9233] (External entity infinite loop DoS), CVE 2016-9063 [https://www.cve.org/CVERecord?id=CVE-2016-9063] (Integer overflow, re-fix), CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] (Fix regression bugs from 2.2.0’s fix to CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718]) and CVE 2012-0876 [https://www.cve.org/CVERecord?id=CVE-2012-0876] (Counter hash flooding with SipHash). Note: the CVE 2016-5300 [https://www.cve.org/CVERecord?id=CVE-2016-5300] (Use os-specific entropy sources like getrandom) doesn’t impact Python, since Python already gets entropy from the OS to set the expat secret using XML_SetHashSalt().

bpo-30500 [https://bugs.python.org/issue?@action=redirect&bpo=30500]: Fix urllib.parse.splithost() to correctly parse fragments. For example, splithost('//127.0.0.1#@evil.com/') now correctly returns the 127.0.0.1 host, instead of treating @evil.com as the host in an authentication (login@host).

bpo-29591 [https://bugs.python.org/issue?@action=redirect&bpo=29591]: Update expat copy from 2.1.1 to 2.2.0 to get fixes of CVE 2016-0718 [https://www.cve.org/CVERecord?id=CVE-2016-0718] and CVE 2016-4472 [https://www.cve.org/CVERecord?id=CVE-2016-4472]. See https://sourceforge.net/p/expat/bugs/537/ for more information.

Core and Builtins

bpo-30876 [https://bugs.python.org/issue?@action=redirect&bpo=30876]: Relative import from unloaded package now reimports the package instead of failing with SystemError. Relative import from non-package now fails with ImportError rather than SystemError.

bpo-30765 [https://bugs.python.org/issue?@action=redirect&bpo=30765]: Avoid blocking in pthread_mutex_lock() when PyThread_acquire_lock() is asked not to block.

bpo-27945 [https://bugs.python.org/issue?@action=redirect&bpo=27945]: Fixed various segfaults with dict when input collections are mutated during searching, inserting or comparing. Based on patches by Duane Griffin and Tim Mitchell.

bpo-25794 [https://bugs.python.org/issue?@action=redirect&bpo=25794]: Fixed type.__setattr__() and type.__delattr__() for non-interned attribute names. Based on patch by Eryk Sun.

bpo-29935 [https://bugs.python.org/issue?@action=redirect&bpo=29935]: Fixed error messages in the index() method of tuple, list and deque when pass indices of wrong type.

bpo-28876 [https://bugs.python.org/issue?@action=redirect&bpo=28876]: bool(range) works even if len(range) raises OverflowError.

bpo-29600 [https://bugs.python.org/issue?@action=redirect&bpo=29600]: Fix wrapping coroutine return values in StopIteration.

bpo-29537 [https://bugs.python.org/issue?@action=redirect&bpo=29537]: Restore runtime compatibility with bytecode files generated by CPython 3.5.0 to 3.5.2, and adjust the eval loop to avoid the problems that could be caused by the malformed variant of the BUILD_MAP_UNPACK_WITH_CALL opcode that they may contain. Patch by Petr Viktorin, Serhiy Storchaka, and Nick Coghlan.

bpo-28598 [https://bugs.python.org/issue?@action=redirect&bpo=28598]: Support __rmod__ for subclasses of str being called before str.__mod__. Patch by Martijn Pieters.

bpo-29602 [https://bugs.python.org/issue?@action=redirect&bpo=29602]: Fix incorrect handling of signed zeros in complex constructor for complex subclasses and for inputs having a __complex__ method. Patch by Serhiy Storchaka.

bpo-29347 [https://bugs.python.org/issue?@action=redirect&bpo=29347]: Fixed possibly dereferencing undefined pointers when creating weakref objects.

bpo-29438 [https://bugs.python.org/issue?@action=redirect&bpo=29438]: Fixed use-after-free problem in key sharing dict.

bpo-29319 [https://bugs.python.org/issue?@action=redirect&bpo=29319]: Prevent RunMainFromImporter overwriting sys.path[0].

bpo-29337 [https://bugs.python.org/issue?@action=redirect&bpo=29337]: Fixed possible BytesWarning when compare the code objects. Warnings could be emitted at compile time.

bpo-29478 [https://bugs.python.org/issue?@action=redirect&bpo=29478]: If max_line_length=None is specified while using the Compat32 policy, it is no longer ignored. Patch by Mircea Cosbuc.

Library

bpo-29403 [https://bugs.python.org/issue?@action=redirect&bpo=29403]: Fix unittest.mock’s autospec to not fail on method-bound builtin functions. Patch by Aaron Gallagher.

bpo-30961 [https://bugs.python.org/issue?@action=redirect&bpo=30961]: Fix decrementing a borrowed reference in tracemalloc.

bpo-30886 [https://bugs.python.org/issue?@action=redirect&bpo=30886]: Fix multiprocessing.Queue.join_thread(): it now waits until the thread completes, even if the thread was started by the same process which created the queue.

bpo-29854 [https://bugs.python.org/issue?@action=redirect&bpo=29854]: Fix segfault in readline when using readline’s history-size option. Patch by Nir Soffer.

bpo-30807 [https://bugs.python.org/issue?@action=redirect&bpo=30807]: signal.setitimer() may disable the timer when passed a tiny value. Tiny values (such as 1e-6) are valid non-zero values for setitimer(), which is specified as taking microsecond-resolution intervals. However, on some platform, our conversion routine could convert 1e-6 into a zero interval, therefore disabling the timer instead of (re-)scheduling it.

bpo-30441 [https://bugs.python.org/issue?@action=redirect&bpo=30441]: Fix bug when modifying os.environ while iterating over it

bpo-30532 [https://bugs.python.org/issue?@action=redirect&bpo=30532]: Fix email header value parser dropping folding white space in certain cases.

bpo-29169 [https://bugs.python.org/issue?@action=redirect&bpo=29169]: Update zlib to 1.2.11.

bpo-30879 [https://bugs.python.org/issue?@action=redirect&bpo=30879]: os.listdir() and os.scandir() now emit bytes names when called with bytes-like argument.

bpo-30746 [https://bugs.python.org/issue?@action=redirect&bpo=30746]: Prohibited the ‘=’ character in environment variable names in os.putenv() and os.spawn*().

bpo-29755 [https://bugs.python.org/issue?@action=redirect&bpo=29755]: Fixed the lgettext() family of functions in the gettext module. They now always return bytes.

bpo-30645 [https://bugs.python.org/issue?@action=redirect&bpo=30645]: Fix path calculation in imp.load_package(), fixing it for cases when a package is only shipped with bytecodes. Patch by Alexandru Ardelean.

bpo-23890 [https://bugs.python.org/issue?@action=redirect&bpo=23890]: unittest.TestCase.assertRaises() now manually breaks a reference cycle to not keep objects alive longer than expected.

bpo-30149 [https://bugs.python.org/issue?@action=redirect&bpo=30149]: inspect.signature() now supports callables with variable-argument parameters wrapped with partialmethod. Patch by Donghee Na.

bpo-29931 [https://bugs.python.org/issue?@action=redirect&bpo=29931]: Fixed comparison check for ipaddress.ip_interface objects. Patch by Sanjay Sundaresan.

bpo-24484 [https://bugs.python.org/issue?@action=redirect&bpo=24484]: Avoid race condition in multiprocessing cleanup.

bpo-28994 [https://bugs.python.org/issue?@action=redirect&bpo=28994]: The traceback no longer displayed for SystemExit raised in a callback registered by atexit.

bpo-30508 [https://bugs.python.org/issue?@action=redirect&bpo=30508]: Don’t log exceptions if Task/Future “cancel()” method was called.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Updates to typing module: Add generic AsyncContextManager, add support for ContextManager on all versions. Original PRs by Jelle Zijlstra and Ivan Levkivskyi

bpo-29870 [https://bugs.python.org/issue?@action=redirect&bpo=29870]: Fix ssl sockets leaks when connection is aborted in asyncio/ssl implementation. Patch by Michaël Sghaïer.

bpo-29743 [https://bugs.python.org/issue?@action=redirect&bpo=29743]: Closing transport during handshake process leaks open socket. Patch by Nikolay Kim

bpo-27585 [https://bugs.python.org/issue?@action=redirect&bpo=27585]: Fix waiter cancellation in asyncio.Lock. Patch by Mathieu Sornay.

bpo-30418 [https://bugs.python.org/issue?@action=redirect&bpo=30418]: On Windows, subprocess.Popen.communicate() now also ignore EINVAL on stdin.write() if the child process is still running but closed the pipe.

bpo-30378 [https://bugs.python.org/issue?@action=redirect&bpo=30378]: Fix the problem that logging.handlers.SysLogHandler cannot handle IPv6 addresses.

bpo-29960 [https://bugs.python.org/issue?@action=redirect&bpo=29960]: Preserve generator state when _random.Random.setstate() raises an exception. Patch by Bryan Olson.

bpo-30414 [https://bugs.python.org/issue?@action=redirect&bpo=30414]: multiprocessing.Queue._feed background running thread do not break from main loop on exception.

bpo-30003 [https://bugs.python.org/issue?@action=redirect&bpo=30003]: Fix handling escape characters in HZ codec. Based on patch by Ma Lin.

bpo-30301 [https://bugs.python.org/issue?@action=redirect&bpo=30301]: Fix AttributeError when using SimpleQueue.empty() under spawn and forkserver start methods.

bpo-30329 [https://bugs.python.org/issue?@action=redirect&bpo=30329]: imaplib and poplib now catch the Windows socket WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid operation was attempted. This error occurs sometimes on SSL connections.

bpo-30375 [https://bugs.python.org/issue?@action=redirect&bpo=30375]: Warnings emitted when compile a regular expression now always point to the line in the user code. Previously they could point into inners of the re module if emitted from inside of groups or conditionals.

bpo-30048 [https://bugs.python.org/issue?@action=redirect&bpo=30048]: Fixed Task.cancel() can be ignored when the task is running coroutine and the coroutine returned without any more await.

bpo-29990 [https://bugs.python.org/issue?@action=redirect&bpo=29990]: Fix range checking in GB18030 decoder. Original patch by Ma Lin.

bpo-26293 [https://bugs.python.org/issue?@action=redirect&bpo=26293]: Change resulted because of zipfile breakage. (See also: bpo-29094 [https://bugs.python.org/issue?@action=redirect&bpo=29094])

bpo-30243 [https://bugs.python.org/issue?@action=redirect&bpo=30243]: Removed the __init__ methods of _json’s scanner and encoder. Misusing them could cause memory leaks or crashes. Now scanner and encoder objects are completely initialized in the __new__ methods.

bpo-30185 [https://bugs.python.org/issue?@action=redirect&bpo=30185]: Avoid KeyboardInterrupt tracebacks in forkserver helper process when Ctrl-C is received.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: add typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes. Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

bpo-30205 [https://bugs.python.org/issue?@action=redirect&bpo=30205]: Fix getsockname() for unbound AF_UNIX sockets on Linux.

bpo-30070 [https://bugs.python.org/issue?@action=redirect&bpo=30070]: Fixed leaks and crashes in errors handling in the parser module.

bpo-30061 [https://bugs.python.org/issue?@action=redirect&bpo=30061]: Fixed crashes in IOBase methods __next__() and readlines() when readline() or __next__() respectively return non-sizeable object. Fixed possible other errors caused by not checking results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

bpo-30068 [https://bugs.python.org/issue?@action=redirect&bpo=30068]: _io._IOBase.readlines will check if it’s closed first when hint is present.

bpo-29694 [https://bugs.python.org/issue?@action=redirect&bpo=29694]: Fixed race condition in pathlib mkdir with flags parents=True. Patch by Armin Rigo.

bpo-29692 [https://bugs.python.org/issue?@action=redirect&bpo=29692]: Fixed arbitrary unchaining of RuntimeError exceptions in contextlib.contextmanager. Patch by Siddharth Velankar.

bpo-29998 [https://bugs.python.org/issue?@action=redirect&bpo=29998]: Pickling and copying ImportError now preserves name and path attributes.

bpo-29942 [https://bugs.python.org/issue?@action=redirect&bpo=29942]: Fix a crash in itertools.chain.from_iterable when encountering long runs of empty iterables.

bpo-27863 [https://bugs.python.org/issue?@action=redirect&bpo=27863]: Fixed multiple crashes in ElementTree caused by race conditions and wrong types.

bpo-28699 [https://bugs.python.org/issue?@action=redirect&bpo=28699]: Fixed a bug in pools in multiprocessing.pool that raising an exception at the very first of an iterable may swallow the exception or make the program hang. Patch by Davin Potts and Xiang Zhang.

bpo-25803 [https://bugs.python.org/issue?@action=redirect&bpo=25803]: Avoid incorrect errors raised by Path.mkdir(exist_ok=True) when the OS gives priority to errors such as EACCES over EEXIST.

bpo-29861 [https://bugs.python.org/issue?@action=redirect&bpo=29861]: Release references to tasks, their arguments and their results as soon as they are finished in multiprocessing.Pool.

bpo-29884 [https://bugs.python.org/issue?@action=redirect&bpo=29884]: faulthandler: Restore the old sigaltstack during teardown. Patch by Christophe Zeitouny.

bpo-25455 [https://bugs.python.org/issue?@action=redirect&bpo=25455]: Fixed crashes in repr of recursive buffered file-like objects.

bpo-29800 [https://bugs.python.org/issue?@action=redirect&bpo=29800]: Fix crashes in partial.__repr__ if the keys of partial.keywords are not strings. Patch by Michael Seifert.

bpo-29742 [https://bugs.python.org/issue?@action=redirect&bpo=29742]: get_extra_info() raises exception if get called on closed ssl transport. Patch by Nikolay Kim.

bpo-8256 [https://bugs.python.org/issue?@action=redirect&bpo=8256]: Fixed possible failing or crashing input() if attributes “encoding” or “errors” of sys.stdin or sys.stdout are not set or are not strings.

bpo-28298 [https://bugs.python.org/issue?@action=redirect&bpo=28298]: Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from accepting big intables (objects that have __int__) as elements. Patch by Oren Milman.

bpo-29615 [https://bugs.python.org/issue?@action=redirect&bpo=29615]: SimpleXMLRPCDispatcher no longer chains KeyError (or any other exception) to exception(s) raised in the dispatched methods. Patch by Petr Motejlek.

bpo-29704 [https://bugs.python.org/issue?@action=redirect&bpo=29704]: asyncio.subprocess.SubprocessStreamProtocol no longer closes before all pipes are closed.

bpo-29703 [https://bugs.python.org/issue?@action=redirect&bpo=29703]: Fix asyncio to support instantiation of new event loops in child processes.

bpo-29376 [https://bugs.python.org/issue?@action=redirect&bpo=29376]: Fix assertion error in threading._DummyThread.is_alive().

bpo-29110 [https://bugs.python.org/issue?@action=redirect&bpo=29110]: Fix file object leak in aifc.open() when file is given as a filesystem path and is not in valid AIFF format. Patch by Anthony Zhang.

bpo-28961 [https://bugs.python.org/issue?@action=redirect&bpo=28961]: Fix unittest.mock._Call helper: don’t ignore the name parameter anymore. Patch written by Jiajun Huang.

bpo-29532 [https://bugs.python.org/issue?@action=redirect&bpo=29532]: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation.

bpo-28556 [https://bugs.python.org/issue?@action=redirect&bpo=28556]: Various updates to typing module: typing.Counter, typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

bpo-29100 [https://bugs.python.org/issue?@action=redirect&bpo=29100]: Fix datetime.fromtimestamp() regression introduced in Python 3.6.0: check minimum and maximum years.

bpo-29519 [https://bugs.python.org/issue?@action=redirect&bpo=29519]: Fix weakref spewing exceptions during interpreter shutdown when used with a rare combination of multiprocessing and custom codecs.

bpo-29416 [https://bugs.python.org/issue?@action=redirect&bpo=29416]: Prevent infinite loop in pathlib.Path.mkdir

bpo-29444 [https://bugs.python.org/issue?@action=redirect&bpo=29444]: Fixed out-of-bounds buffer access in the group() method of the match object. Based on patch by WGH.

bpo-29335 [https://bugs.python.org/issue?@action=redirect&bpo=29335]: Fix subprocess.Popen.wait() when the child process has exited to a stopped instead of terminated state (ex: when under ptrace).

bpo-29290 [https://bugs.python.org/issue?@action=redirect&bpo=29290]: Fix a regression in argparse that help messages would wrap at non-breaking spaces.

bpo-28735 [https://bugs.python.org/issue?@action=redirect&bpo=28735]: Fixed the comparison of mock.MagickMock with mock.ANY.

bpo-29011 [https://bugs.python.org/issue?@action=redirect&bpo=29011]: Fix an important omission by adding Deque to the typing module.

bpo-29219 [https://bugs.python.org/issue?@action=redirect&bpo=29219]: Fixed infinite recursion in the repr of uninitialized ctypes.CDLL instances.

bpo-28969 [https://bugs.python.org/issue?@action=redirect&bpo=28969]: Fixed race condition in C implementation of functools.lru_cache. KeyError could be raised when cached function with full cache was simultaneously called from different threads with the same uncached arguments.

bpo-29142 [https://bugs.python.org/issue?@action=redirect&bpo=29142]: In urllib.request, suffixes in no_proxy environment variable with leading dots could match related hostnames again (e.g. .b.c matches a.b.c). Patch by Milan Oberkirch.

Documentation

bpo-30176 [https://bugs.python.org/issue?@action=redirect&bpo=30176]: Add missing attribute related constants in curses documentation.

bpo-26985 [https://bugs.python.org/issue?@action=redirect&bpo=26985]: Add missing info of code object in inspect documentation.

bpo-28929 [https://bugs.python.org/issue?@action=redirect&bpo=28929]: Link the documentation to its source file on GitHub.

bpo-25008 [https://bugs.python.org/issue?@action=redirect&bpo=25008]: Document smtpd.py as effectively deprecated and add a pointer to aiosmtpd, a third-party asyncio-based replacement.

bpo-26355 [https://bugs.python.org/issue?@action=redirect&bpo=26355]: Add canonical header link on each page to corresponding major version of the documentation. Patch by Matthias Bussonnier.

bpo-29349 [https://bugs.python.org/issue?@action=redirect&bpo=29349]: Fix Python 2 syntax in code for building the documentation.

Tests

bpo-30822 [https://bugs.python.org/issue?@action=redirect&bpo=30822]: Fix regrtest command line parser to allow passing -u extralargefile to run test_zipfile64.

bpo-30383 [https://bugs.python.org/issue?@action=redirect&bpo=30383]: regrtest: Enhance regrtest and backport features from the master branch. Add options: –coverage, –testdir, –list-tests (list test files, don’t run them), –list-cases (list test identifiers, don’t run them, bpo-30523 [https://bugs.python.org/issue?@action=redirect&bpo=30523]), –matchfile (load a list of test filters from a text file, bpo-30540 [https://bugs.python.org/issue?@action=redirect&bpo=30540]), –slowest (alias to –slow). Enhance output: add timestamp, test result, currently running tests, “Tests result: xxx” summary with total duration, etc. Fix reference leak hunting in regrtest, –huntrleaks: regrtest now warms up caches, create explicitly all internal singletons which are created on demand to prevent false positives when checking for reference leaks. (bpo-30675 [https://bugs.python.org/issue?@action=redirect&bpo=30675]).

bpo-30357 [https://bugs.python.org/issue?@action=redirect&bpo=30357]: test_thread: setUp() now uses support.threading_setup() and support.threading_cleanup() to wait until threads complete to avoid random side effects on following tests. Initial patch written by Grzegorz Grzywacz.

bpo-28087 [https://bugs.python.org/issue?@action=redirect&bpo=28087]: Skip test_asyncore and test_eintr poll failures on macOS. Skip some tests of select.poll when running on macOS due to unresolved issues with the underlying system poll function on some macOS versions.

bpo-30197 [https://bugs.python.org/issue?@action=redirect&bpo=30197]: Enhanced functions swap_attr() and swap_item() in the test.support module. They now work when delete replaced attribute or item inside the with statement. The old value of the attribute or item (or None if it doesn’t exist) now will be assigned to the target of the “as” clause, if there is one.

bpo-29571 [https://bugs.python.org/issue?@action=redirect&bpo=29571]: to match the behaviour of the re.LOCALE flag, test_re.test_locale_flag now uses locale.getpreferredencoding(False) to determine the candidate encoding for the test regex (allowing it to correctly skip the test when the default locale encoding is a multi-byte encoding)

Build

bpo-29243 [https://bugs.python.org/issue?@action=redirect&bpo=29243]: Prevent unnecessary rebuilding of Python during make test, make install and some other make targets when configured with --enable-optimizations.

bpo-23404 [https://bugs.python.org/issue?@action=redirect&bpo=23404]: Don’t regenerate generated files based on file modification time anymore: the action is now explicit. Replace make touch with make regen-all.

bpo-29643 [https://bugs.python.org/issue?@action=redirect&bpo=29643]: Fix --enable-optimization didn’t work.

Windows

bpo-30687 [https://bugs.python.org/issue?@action=redirect&bpo=30687]: Locate msbuild.exe on Windows when building rather than vcvarsall.bat

bpo-29392 [https://bugs.python.org/issue?@action=redirect&bpo=29392]: Prevent crash when passing invalid arguments into msvcrt module.

C API

bpo-27867 [https://bugs.python.org/issue?@action=redirect&bpo=27867]: Function PySlice_GetIndicesEx() is replaced with a macro if Py_LIMITED_API is set to the value between 0x03050400 and 0x03060000 (not including) or 0x03060100 or higher.

bpo-29083 [https://bugs.python.org/issue?@action=redirect&bpo=29083]: Fixed the declaration of some public API functions. PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and Py_BuildValue() were not available in limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

Python 3.5.3 final

Release date: 2017-01-17

There were no code changes between 3.5.3rc1 and 3.5.3 final.

Python 3.5.3 release candidate 1

Release date: 2017-01-02

Security

bpo-27278 [https://bugs.python.org/issue?@action=redirect&bpo=27278]: Fix os.urandom() implementation using getrandom() on Linux. Truncate size to INT_MAX and loop until we collected enough random bytes, instead of casting a directly Py_ssize_t to int.

bpo-22636 [https://bugs.python.org/issue?@action=redirect&bpo=22636]: Avoid shell injection problems with ctypes.util.find_library().

Core and Builtins

bpo-29073 [https://bugs.python.org/issue?@action=redirect&bpo=29073]: bytearray formatting no longer truncates on first null byte.

bpo-28932 [https://bugs.python.org/issue?@action=redirect&bpo=28932]: Do not include <sys/random.h> if it does not exist.

bpo-28147 [https://bugs.python.org/issue?@action=redirect&bpo=28147]: Fix a memory leak in split-table dictionaries: setattr() must not convert combined table into split table.

bpo-25677 [https://bugs.python.org/issue?@action=redirect&bpo=25677]: Correct the positioning of the syntax error caret for indented blocks. Based on patch by Michael Layzell.

bpo-29000 [https://bugs.python.org/issue?@action=redirect&bpo=29000]: Fixed bytes formatting of octals with zero padding in alternate form.

bpo-28512 [https://bugs.python.org/issue?@action=redirect&bpo=28512]: Fixed setting the offset attribute of SyntaxError by PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

bpo-28991 [https://bugs.python.org/issue?@action=redirect&bpo=28991]: functools.lru_cache() was susceptible to an obscure reentrancy bug caused by a monkey-patched len() function.

bpo-28648 [https://bugs.python.org/issue?@action=redirect&bpo=28648]: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X when decode astral characters. Patch by Xiang Zhang.

bpo-19398 [https://bugs.python.org/issue?@action=redirect&bpo=19398]: Extra slash no longer added to sys.path components in case of empty compile-time PYTHONPATH components.

bpo-28426 [https://bugs.python.org/issue?@action=redirect&bpo=28426]: Fixed potential crash in PyUnicode_AsDecodedObject() in debug build.

bpo-23782 [https://bugs.python.org/issue?@action=redirect&bpo=23782]: Fixed possible memory leak in _PyTraceback_Add() and exception loss in PyTraceBack_Here().

bpo-28379 [https://bugs.python.org/issue?@action=redirect&bpo=28379]: Added sanity checks and tests for PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: The type of long range iterator is now registered as Iterator. Patch by Oren Milman.

bpo-28376 [https://bugs.python.org/issue?@action=redirect&bpo=28376]: The constructor of range_iterator now checks that step is not 0. Patch by Oren Milman.

bpo-26906 [https://bugs.python.org/issue?@action=redirect&bpo=26906]: Resolving special methods of uninitialized type now causes implicit initialization of the type instead of a fail.

bpo-18287 [https://bugs.python.org/issue?@action=redirect&bpo=18287]: PyType_Ready() now checks that tp_name is not NULL. Original patch by Niklas Koep.

bpo-24098 [https://bugs.python.org/issue?@action=redirect&bpo=24098]: Fixed possible crash when AST is changed in process of compiling it.

bpo-28350 [https://bugs.python.org/issue?@action=redirect&bpo=28350]: String constants with null character no longer interned.

bpo-26617 [https://bugs.python.org/issue?@action=redirect&bpo=26617]: Fix crash when GC runs during weakref callbacks.

bpo-27942 [https://bugs.python.org/issue?@action=redirect&bpo=27942]: String constants now interned recursively in tuples and frozensets.

bpo-21578 [https://bugs.python.org/issue?@action=redirect&bpo=21578]: Fixed misleading error message when ImportError called with invalid keyword args.

bpo-28203 [https://bugs.python.org/issue?@action=redirect&bpo=28203]: Fix incorrect type in error message from complex(1.0, {2:3}). Patch by Soumya Sharma.

bpo-27955 [https://bugs.python.org/issue?@action=redirect&bpo=27955]: Fallback on reading /dev/urandom device when the getrandom() syscall fails with EPERM, for example when blocked by SECCOMP.

bpo-28131 [https://bugs.python.org/issue?@action=redirect&bpo=28131]: Fix a regression in zipimport’s compile_source(). zipimport should use the same optimization level as the interpreter.

bpo-25221 [https://bugs.python.org/issue?@action=redirect&bpo=25221]: Fix corrupted result from PyLong_FromLong(0) when Python is compiled with NSMALLPOSINTS = 0.

bpo-25758 [https://bugs.python.org/issue?@action=redirect&bpo=25758]: Prevents zipimport from unnecessarily encoding a filename (patch by Eryk Sun)

bpo-28189 [https://bugs.python.org/issue?@action=redirect&bpo=28189]: dictitems_contains no longer swallows compare errors. (Patch by Xiang Zhang)

bpo-27812 [https://bugs.python.org/issue?@action=redirect&bpo=27812]: Properly clear out a generator’s frame’s backreference to the generator to prevent crashes in frame.clear().

bpo-27811 [https://bugs.python.org/issue?@action=redirect&bpo=27811]: Fix a crash when a coroutine that has not been awaited is finalized with warnings-as-errors enabled.

bpo-27587 [https://bugs.python.org/issue?@action=redirect&bpo=27587]: Fix another issue found by PVS-Studio: Null pointer check after use of ‘def’ in _PyState_AddModule(). Initial patch by Christian Heimes.

bpo-26020 [https://bugs.python.org/issue?@action=redirect&bpo=26020]: set literal evaluation order did not match documented behaviour.

bpo-27782 [https://bugs.python.org/issue?@action=redirect&bpo=27782]: Multi-phase extension module import now correctly allows the m_methods field to be used to add module level functions to instances of non-module types returned from Py_create_mod. Patch by Xiang Zhang.

bpo-27936 [https://bugs.python.org/issue?@action=redirect&bpo=27936]: The round() function accepted a second None argument for some types but not for others. Fixed the inconsistency by accepting None for all numeric types.

bpo-27487 [https://bugs.python.org/issue?@action=redirect&bpo=27487]: Warn if a submodule argument to “python -m” or runpy.run_module() is found in sys.modules after parent packages are imported, but before the submodule is executed.

bpo-27558 [https://bugs.python.org/issue?@action=redirect&bpo=27558]: Fix a SystemError in the implementation of “raise” statement. In a brand new thread, raise a RuntimeError since there is no active exception to reraise. Patch written by Xiang Zhang.

bpo-27419 [https://bugs.python.org/issue?@action=redirect&bpo=27419]: Standard __import__() no longer look up “__import__” in globals or builtins for importing submodules or “from import”. Fixed handling an error of non-string package name.

bpo-27083 [https://bugs.python.org/issue?@action=redirect&bpo=27083]: Respect the PYTHONCASEOK environment variable under Windows.

bpo-27514 [https://bugs.python.org/issue?@action=redirect&bpo=27514]: Make having too many statically nested blocks a SyntaxError instead of SystemError.

bpo-27473 [https://bugs.python.org/issue?@action=redirect&bpo=27473]: Fixed possible integer overflow in bytes and bytearray concatenations. Patch by Xiang Zhang.

bpo-27507 [https://bugs.python.org/issue?@action=redirect&bpo=27507]: Add integer overflow check in bytearray.extend(). Patch by Xiang Zhang.

bpo-27581 [https://bugs.python.org/issue?@action=redirect&bpo=27581]: Don’t rely on wrapping for overflow check in PySequence_Tuple(). Patch by Xiang Zhang.

bpo-27443 [https://bugs.python.org/issue?@action=redirect&bpo=27443]: __length_hint__() of bytearray iterators no longer return a negative integer for a resized bytearray.

bpo-27942 [https://bugs.python.org/issue?@action=redirect&bpo=27942]: Fix memory leak in codeobject.c

Library

bpo-15812 [https://bugs.python.org/issue?@action=redirect&bpo=15812]: inspect.getframeinfo() now correctly shows the first line of a context. Patch by Sam Breese.

bpo-29094 [https://bugs.python.org/issue?@action=redirect&bpo=29094]: Offsets in a ZIP file created with extern file object and modes “w” and “x” now are relative to the start of the file.

bpo-13051 [https://bugs.python.org/issue?@action=redirect&bpo=13051]: Fixed recursion errors in large or resized curses.textpad.Textbox. Based on patch by Tycho Andersen.

bpo-29119 [https://bugs.python.org/issue?@action=redirect&bpo=29119]: Fix weakrefs in the pure python version of collections.OrderedDict move_to_end() method. Contributed by Andra Bogildea.

bpo-9770 [https://bugs.python.org/issue?@action=redirect&bpo=9770]: curses.ascii predicates now work correctly with negative integers.

bpo-28427 [https://bugs.python.org/issue?@action=redirect&bpo=28427]: old keys should not remove new values from WeakValueDictionary when collecting from another thread.

bpo-28923 [https://bugs.python.org/issue?@action=redirect&bpo=28923]: Remove editor artifacts from Tix.py.

bpo-28871 [https://bugs.python.org/issue?@action=redirect&bpo=28871]: Fixed a crash when deallocate deep ElementTree.

bpo-19542 [https://bugs.python.org/issue?@action=redirect&bpo=19542]: Fix bugs in WeakValueDictionary.setdefault() and WeakValueDictionary.pop() when a GC collection happens in another thread.

bpo-20191 [https://bugs.python.org/issue?@action=redirect&bpo=20191]: Fixed a crash in resource.prlimit() when pass a sequence that doesn’t own its elements as limits.

bpo-28779 [https://bugs.python.org/issue?@action=redirect&bpo=28779]: multiprocessing.set_forkserver_preload() would crash the forkserver process if a preloaded module instantiated some multiprocessing objects such as locks.

bpo-28847 [https://bugs.python.org/issue?@action=redirect&bpo=28847]: dbm.dumb now supports reading read-only files and no longer writes the index file when it is not changed.

bpo-25659 [https://bugs.python.org/issue?@action=redirect&bpo=25659]: In ctypes, prevent a crash calling the from_buffer() and from_buffer_copy() methods on abstract classes like Array.

bpo-28732 [https://bugs.python.org/issue?@action=redirect&bpo=28732]: Fix crash in os.spawnv() with no elements in args

bpo-28485 [https://bugs.python.org/issue?@action=redirect&bpo=28485]: Always raise ValueError for negative compileall.compile_dir(workers=…) parameter, even when multithreading is unavailable.

bpo-28387 [https://bugs.python.org/issue?@action=redirect&bpo=28387]: Fixed possible crash in _io.TextIOWrapper deallocator when the garbage collector is invoked in other thread. Based on patch by Sebastian Cufre.

bpo-27517 [https://bugs.python.org/issue?@action=redirect&bpo=27517]: LZMA compressor and decompressor no longer raise exceptions if given empty data twice. Patch by Benjamin Fogle.

bpo-28549 [https://bugs.python.org/issue?@action=redirect&bpo=28549]: Fixed segfault in curses’s addch() with ncurses6.

bpo-28449 [https://bugs.python.org/issue?@action=redirect&bpo=28449]: tarfile.open() with mode “r” or “r:” now tries to open a tar file with compression before trying to open it without compression. Otherwise it had 50% chance failed with ignore_zeros=True.

bpo-23262 [https://bugs.python.org/issue?@action=redirect&bpo=23262]: The webbrowser module now supports Firefox 36+ and derived browsers. Based on patch by Oleg Broytman.

bpo-27939 [https://bugs.python.org/issue?@action=redirect&bpo=27939]: Fixed bugs in tkinter.ttk.LabeledScale and tkinter.Scale caused by representing the scale as float value internally in Tk. tkinter.IntVar now works if float value is set to underlying Tk variable.

bpo-28255 [https://bugs.python.org/issue?@action=redirect&bpo=28255]: calendar.TextCalendar().prmonth() no longer prints a space at the start of new line after printing a month’s calendar. Patch by Xiang Zhang.

bpo-20491 [https://bugs.python.org/issue?@action=redirect&bpo=20491]: The textwrap.TextWrapper class now honors non-breaking spaces. Based on patch by Kaarle Ritvanen.

bpo-28353 [https://bugs.python.org/issue?@action=redirect&bpo=28353]: os.fwalk() no longer fails on broken links.

bpo-25464 [https://bugs.python.org/issue?@action=redirect&bpo=25464]: Fixed HList.header_exists() in tkinter.tix module by addin a workaround to Tix library bug.

bpo-28488 [https://bugs.python.org/issue?@action=redirect&bpo=28488]: shutil.make_archive() no longer add entry “./” to ZIP archive.

bpo-24452 [https://bugs.python.org/issue?@action=redirect&bpo=24452]: Make webbrowser support Chrome on Mac OS X.

bpo-20766 [https://bugs.python.org/issue?@action=redirect&bpo=20766]: Fix references leaked by pdb in the handling of SIGINT handlers.

bpo-26293 [https://bugs.python.org/issue?@action=redirect&bpo=26293]: Fixed writing ZIP files that starts not from the start of the file. Offsets in ZIP file now are relative to the start of the archive in conforming to the specification.

bpo-28321 [https://bugs.python.org/issue?@action=redirect&bpo=28321]: Fixed writing non-BMP characters with binary format in plistlib.

bpo-28322 [https://bugs.python.org/issue?@action=redirect&bpo=28322]: Fixed possible crashes when unpickle itertools objects from incorrect pickle data. Based on patch by John Leitch.

Fix possible integer overflows and crashes in the mmap module with unusual usage patterns.

bpo-1703178 [https://bugs.python.org/issue?@action=redirect&bpo=1703178]: Fix the ability to pass the –link-objects option to the distutils build_ext command.

bpo-28253 [https://bugs.python.org/issue?@action=redirect&bpo=28253]: Fixed calendar functions for extreme months: 0001-01 and 9999-12. Methods itermonthdays() and itermonthdays2() are reimplemented so that they don’t call itermonthdates() which can cause datetime.date under/overflow.

bpo-28275 [https://bugs.python.org/issue?@action=redirect&bpo=28275]: Fixed possible use after free in the decompress() methods of the LZMADecompressor and BZ2Decompressor classes. Original patch by John Leitch.

bpo-27897 [https://bugs.python.org/issue?@action=redirect&bpo=27897]: Fixed possible crash in sqlite3.Connection.create_collation() if pass invalid string-like object as a name. Patch by Xiang Zhang.

bpo-18893 [https://bugs.python.org/issue?@action=redirect&bpo=18893]: Fix invalid exception handling in Lib/ctypes/macholib/dyld.py. Patch by Madison May.

bpo-27611 [https://bugs.python.org/issue?@action=redirect&bpo=27611]: Fixed support of default root window in the tkinter.tix module.

bpo-27348 [https://bugs.python.org/issue?@action=redirect&bpo=27348]: In the traceback module, restore the formatting of exception messages like “Exception: None”. This fixes a regression introduced in 3.5a2.

bpo-25651 [https://bugs.python.org/issue?@action=redirect&bpo=25651]: Allow false values to be used for msg parameter of subTest().

bpo-27932 [https://bugs.python.org/issue?@action=redirect&bpo=27932]: Prevent memory leak in win32_ver().

Fix UnboundLocalError in socket._sendfile_use_sendfile.

bpo-28075 [https://bugs.python.org/issue?@action=redirect&bpo=28075]: Check for ERROR_ACCESS_DENIED in Windows implementation of os.stat(). Patch by Eryk Sun.

bpo-25270 [https://bugs.python.org/issue?@action=redirect&bpo=25270]: Prevent codecs.escape_encode() from raising SystemError when an empty bytestring is passed.

bpo-28181 [https://bugs.python.org/issue?@action=redirect&bpo=28181]: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

bpo-25895 [https://bugs.python.org/issue?@action=redirect&bpo=25895]: Enable WebSocket URL schemes in urllib.parse.urljoin. Patch by Gergely Imreh and Markus Holtermann.

bpo-27599 [https://bugs.python.org/issue?@action=redirect&bpo=27599]: Fixed buffer overrun in binascii.b2a_qp() and binascii.a2b_qp().

bpo-19003 [https://bugs.python.org/issue?@action=redirect&bpo=19003]: m email.generator now replaces only \r and/or \n line endings, per the RFC, instead of all unicode line endings.

bpo-28019 [https://bugs.python.org/issue?@action=redirect&bpo=28019]: itertools.count() no longer rounds non-integer step in range between 1.0 and 2.0 to 1.

bpo-25969 [https://bugs.python.org/issue?@action=redirect&bpo=25969]: Update the lib2to3 grammar to handle the unpacking generalizations added in 3.5.

bpo-14977 [https://bugs.python.org/issue?@action=redirect&bpo=14977]: mailcap now respects the order of the lines in the mailcap files (“first match”), as required by RFC 1542. Patch by Michael Lazar.

bpo-24594 [https://bugs.python.org/issue?@action=redirect&bpo=24594]: Validates persist parameter when opening MSI database

bpo-17582 [https://bugs.python.org/issue?@action=redirect&bpo=17582]: xml.etree.ElementTree nows preserves whitespaces in attributes (Patch by Duane Griffin. Reviewed and approved by Stefan Behnel.)

bpo-28047 [https://bugs.python.org/issue?@action=redirect&bpo=28047]: Fixed calculation of line length used for the base64 CTE in the new email policies.

bpo-27445 [https://bugs.python.org/issue?@action=redirect&bpo=27445]: Don’t pass str(_charset) to MIMEText.set_payload(). Patch by Claude Paroz.

bpo-22450 [https://bugs.python.org/issue?@action=redirect&bpo=22450]: urllib now includes an Accept: */* header among the default headers. This makes the results of REST API requests more consistent and predictable especially when proxy servers are involved.

lib2to3.pgen3.driver.load_grammar() now creates a stable cache file between runs given the same Grammar.txt input regardless of the hash randomization setting.

bpo-27570 [https://bugs.python.org/issue?@action=redirect&bpo=27570]: Avoid zero-length memcpy() etc calls with null source pointers in the “ctypes” and “array” modules.

bpo-22233 [https://bugs.python.org/issue?@action=redirect&bpo=22233]: Break email header lines only on the RFC specified CR and LF characters, not on arbitrary unicode line breaks. This also fixes a bug in HTTP header parsing.

bpo-27988 [https://bugs.python.org/issue?@action=redirect&bpo=27988]: Fix email iter_attachments incorrect mutation of payload list.

bpo-27691 [https://bugs.python.org/issue?@action=redirect&bpo=27691]: Fix ssl module’s parsing of GEN_RID subject alternative name fields in X.509 certs.

bpo-27850 [https://bugs.python.org/issue?@action=redirect&bpo=27850]: Remove 3DES from ssl module’s default cipher list to counter measure sweet32 attack (CVE 2016-2183 [https://www.cve.org/CVERecord?id=CVE-2016-2183]).

bpo-27766 [https://bugs.python.org/issue?@action=redirect&bpo=27766]: Add ChaCha20 Poly1305 to ssl module’s default cipher list. (Required OpenSSL 1.1.0 or LibreSSL).

bpo-26470 [https://bugs.python.org/issue?@action=redirect&bpo=26470]: Port ssl and hashlib module to OpenSSL 1.1.0.

Remove support for passing a file descriptor to os.access. It never worked but previously didn’t raise.

bpo-12885 [https://bugs.python.org/issue?@action=redirect&bpo=12885]: Fix error when distutils encounters symlink.

bpo-27881 [https://bugs.python.org/issue?@action=redirect&bpo=27881]: Fixed possible bugs when setting sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

bpo-27861 [https://bugs.python.org/issue?@action=redirect&bpo=27861]: Fixed a crash in sqlite3.Connection.cursor() when a factory creates not a cursor. Patch by Xiang Zhang.

bpo-19884 [https://bugs.python.org/issue?@action=redirect&bpo=19884]: Avoid spurious output on OS X with Gnu Readline.

bpo-27706 [https://bugs.python.org/issue?@action=redirect&bpo=27706]: Restore deterministic behavior of random.Random().seed() for string seeds using seeding version 1. Allows sequences of calls to random() to exactly match those obtained in Python 2. Patch by Nofar Schnider.

bpo-10513 [https://bugs.python.org/issue?@action=redirect&bpo=10513]: Fix a regression in Connection.commit(). Statements should not be reset after a commit.

A new version of typing.py from https://github.com/python/typing: Collection (only for 3.6) (bpo-27598 [https://bugs.python.org/issue?@action=redirect&bpo=27598]). Add FrozenSet to __all__ (upstream #261). Fix crash in _get_type_vars() (upstream #259). Remove the dict constraint in ForwardRef._eval_type (upstream #252).

bpo-27539 [https://bugs.python.org/issue?@action=redirect&bpo=27539]: Fix unnormalised Fraction.__pow__ result in the case of negative exponent and negative base.

bpo-21718 [https://bugs.python.org/issue?@action=redirect&bpo=21718]: cursor.description is now available for queries using CTEs.

bpo-2466 [https://bugs.python.org/issue?@action=redirect&bpo=2466]: posixpath.ismount now correctly recognizes mount points which the user does not have permission to access.

bpo-27773 [https://bugs.python.org/issue?@action=redirect&bpo=27773]: Correct some memory management errors server_hostname in _ssl.wrap_socket().

bpo-26750 [https://bugs.python.org/issue?@action=redirect&bpo=26750]: unittest.mock.create_autospec() now works properly for subclasses of property() and other data descriptors.

In the curses module, raise an error if window.getstr() or window.instr() is passed a negative value.

bpo-27783 [https://bugs.python.org/issue?@action=redirect&bpo=27783]: Fix possible usage of uninitialized memory in operator.methodcaller.

bpo-27774 [https://bugs.python.org/issue?@action=redirect&bpo=27774]: Fix possible Py_DECREF on unowned object in _sre.

bpo-27760 [https://bugs.python.org/issue?@action=redirect&bpo=27760]: Fix possible integer overflow in binascii.b2a_qp.

bpo-27758 [https://bugs.python.org/issue?@action=redirect&bpo=27758]: Fix possible integer overflow in the _csv module for large record lengths.

bpo-27568 [https://bugs.python.org/issue?@action=redirect&bpo=27568]: Prevent HTTPoxy attack (CVE 2016-1000110 [https://www.cve.org/CVERecord?id=CVE-2016-1000110]). Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is set, which indicates that the script is in CGI mode.

bpo-27656 [https://bugs.python.org/issue?@action=redirect&bpo=27656]: Do not assume sched.h defines any SCHED_* constants.

bpo-27130 [https://bugs.python.org/issue?@action=redirect&bpo=27130]: In the “zlib” module, fix handling of large buffers (typically 4 GiB) when compressing and decompressing. Previously, inputs were limited to 4 GiB, and compression and decompression operations did not properly handle results of 4 GiB.

bpo-27533 [https://bugs.python.org/issue?@action=redirect&bpo=27533]: Release GIL in nt._isdir

bpo-17711 [https://bugs.python.org/issue?@action=redirect&bpo=17711]: Fixed unpickling by the persistent ID with protocol 0. Original patch by Alexandre Vassalotti.

bpo-27522 [https://bugs.python.org/issue?@action=redirect&bpo=27522]: Avoid an unintentional reference cycle in email.feedparser.

bpo-26844 [https://bugs.python.org/issue?@action=redirect&bpo=26844]: Fix error message for imp.find_module() to refer to ‘path’ instead of ‘name’. Patch by Lev Maximov.

bpo-23804 [https://bugs.python.org/issue?@action=redirect&bpo=23804]: Fix SSL zero-length recv() calls to not block and not raise an error about unclean EOF.

bpo-27466 [https://bugs.python.org/issue?@action=redirect&bpo=27466]: Change time format returned by http.cookie.time2netscape, confirming the netscape cookie format and making it consistent with documentation.

bpo-26664 [https://bugs.python.org/issue?@action=redirect&bpo=26664]: Fix activate.fish by removing mis-use of $.

bpo-22115 [https://bugs.python.org/issue?@action=redirect&bpo=22115]: Fixed tracing Tkinter variables: trace_vdelete() with wrong mode no longer break tracing, trace_vinfo() now always returns a list of pairs of strings, tracing in the “u” mode now works.

Fix a scoping issue in importlib.util.LazyLoader which triggered an UnboundLocalError when lazy-loading a module that was already put into sys.modules.

bpo-27079 [https://bugs.python.org/issue?@action=redirect&bpo=27079]: Fixed curses.ascii functions isblank(), iscntrl() and ispunct().

bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754]: Some functions (compile() etc) accepted a filename argument encoded as an iterable of integers. Now only strings and byte-like objects are accepted.

bpo-27048 [https://bugs.python.org/issue?@action=redirect&bpo=27048]: Prevents distutils failing on Windows when environment variables contain non-ASCII characters

bpo-27330 [https://bugs.python.org/issue?@action=redirect&bpo=27330]: Fixed possible leaks in the ctypes module.

bpo-27238 [https://bugs.python.org/issue?@action=redirect&bpo=27238]: Got rid of bare excepts in the turtle module. Original patch by Jelle Zijlstra.

bpo-27122 [https://bugs.python.org/issue?@action=redirect&bpo=27122]: When an exception is raised within the context being managed by a contextlib.ExitStack() and one of the exit stack generators catches and raises it in a chain, do not re-raise the original exception when exiting, let the new chained one through. This avoids the PEP 479 [https://peps.python.org/pep-0479/] bug described in issue25782.

bpo-26386 [https://bugs.python.org/issue?@action=redirect&bpo=26386]: Fixed ttk.TreeView selection operations with item id’s containing spaces.

bpo-16182 [https://bugs.python.org/issue?@action=redirect&bpo=16182]: Fix various functions in the “readline” module to use the locale encoding, and fix get_begidx() and get_endidx() to return code point indexes.

bpo-27392 [https://bugs.python.org/issue?@action=redirect&bpo=27392]: Add loop.connect_accepted_socket(). Patch by Jim Fulton.

bpo-27930 [https://bugs.python.org/issue?@action=redirect&bpo=27930]: Improved behaviour of logging.handlers.QueueListener. Thanks to Paulo Andrade and Petr Viktorin for the analysis and patch.

bpo-21201 [https://bugs.python.org/issue?@action=redirect&bpo=21201]: Improves readability of multiprocessing error message. Thanks to Wojciech Walczak for patch.

bpo-27456 [https://bugs.python.org/issue?@action=redirect&bpo=27456]: asyncio: Set TCP_NODELAY by default.

bpo-27906 [https://bugs.python.org/issue?@action=redirect&bpo=27906]: Fix socket accept exhaustion during high TCP traffic. Patch by Kevin Conway.

bpo-28174 [https://bugs.python.org/issue?@action=redirect&bpo=28174]: Handle when SO_REUSEPORT isn’t properly supported. Patch by Seth Michael Larson.

bpo-26654 [https://bugs.python.org/issue?@action=redirect&bpo=26654]: Inspect functools.partial in asyncio.Handle.__repr__. Patch by iceboy.

bpo-26909 [https://bugs.python.org/issue?@action=redirect&bpo=26909]: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

bpo-28176 [https://bugs.python.org/issue?@action=redirect&bpo=28176]: Fix callbacks race in asyncio.SelectorLoop.sock_connect.

bpo-27759 [https://bugs.python.org/issue?@action=redirect&bpo=27759]: Fix selectors incorrectly retain invalid file descriptors. Patch by Mark Williams.

bpo-28368 [https://bugs.python.org/issue?@action=redirect&bpo=28368]: Refuse monitoring processes if the child watcher has no loop attached. Patch by Vincent Michel.

bpo-28369 [https://bugs.python.org/issue?@action=redirect&bpo=28369]: Raise RuntimeError when transport’s FD is used with add_reader, add_writer, etc.

bpo-28370 [https://bugs.python.org/issue?@action=redirect&bpo=28370]: Speedup asyncio.StreamReader.readexactly. Patch by Коренберг Марк.

bpo-28371 [https://bugs.python.org/issue?@action=redirect&bpo=28371]: Deprecate passing asyncio.Handles to run_in_executor.

bpo-28372 [https://bugs.python.org/issue?@action=redirect&bpo=28372]: Fix asyncio to support formatting of non-python coroutines.

bpo-28399 [https://bugs.python.org/issue?@action=redirect&bpo=28399]: Remove UNIX socket from FS before binding. Patch by Коренберг Марк.

bpo-27972 [https://bugs.python.org/issue?@action=redirect&bpo=27972]: Prohibit Tasks to await on themselves.

bpo-26923 [https://bugs.python.org/issue?@action=redirect&bpo=26923]: Fix asyncio.Gather to refuse being cancelled once all children are done. Patch by Johannes Ebke.

bpo-26796 [https://bugs.python.org/issue?@action=redirect&bpo=26796]: Don’t configure the number of workers for default threadpool executor. Initial patch by Hans Lawrenz.

bpo-28600 [https://bugs.python.org/issue?@action=redirect&bpo=28600]: Optimize loop.call_soon().

bpo-28613 [https://bugs.python.org/issue?@action=redirect&bpo=28613]: Fix get_event_loop() return the current loop if called from coroutines/callbacks.

bpo-28639 [https://bugs.python.org/issue?@action=redirect&bpo=28639]: Fix inspect.isawaitable to always return bool Patch by Justin Mayfield.

bpo-28652 [https://bugs.python.org/issue?@action=redirect&bpo=28652]: Make loop methods reject socket kinds they do not support.

bpo-28653 [https://bugs.python.org/issue?@action=redirect&bpo=28653]: Fix a refleak in functools.lru_cache.

bpo-28703 [https://bugs.python.org/issue?@action=redirect&bpo=28703]: Fix asyncio.iscoroutinefunction to handle Mock objects.

bpo-24142 [https://bugs.python.org/issue?@action=redirect&bpo=24142]: Reading a corrupt config file left the parser in an invalid state. Original patch by Florian Höch.

bpo-28990 [https://bugs.python.org/issue?@action=redirect&bpo=28990]: Fix SSL hanging if connection is closed before handshake completed. (Patch by HoHo-Ho)

IDLE

bpo-15308 [https://bugs.python.org/issue?@action=redirect&bpo=15308]: Add ‘interrupt execution’ (^C) to Shell menu. Patch by Roger Serwy, updated by Bayard Randel.

bpo-27922 [https://bugs.python.org/issue?@action=redirect&bpo=27922]: Stop IDLE tests from ‘flashing’ gui widgets on the screen.

Add version to title of IDLE help window.

bpo-25564 [https://bugs.python.org/issue?@action=redirect&bpo=25564]: In section on IDLE – console differences, mention that using exec means that __builtins__ is defined for each statement.

bpo-27714 [https://bugs.python.org/issue?@action=redirect&bpo=27714]: text_textview and test_autocomplete now pass when re-run in the same process. This occurs when test_idle fails when run with the -w option but without -jn. Fix warning from test_config.

bpo-25507 [https://bugs.python.org/issue?@action=redirect&bpo=25507]: IDLE no longer runs buggy code because of its tkinter imports. Users must include the same imports required to run directly in Python.

bpo-27452 [https://bugs.python.org/issue?@action=redirect&bpo=27452]: add line counter and crc to IDLE configHandler test dump.

bpo-27365 [https://bugs.python.org/issue?@action=redirect&bpo=27365]: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.

bpo-27245 [https://bugs.python.org/issue?@action=redirect&bpo=27245]: IDLE: Cleanly delete custom themes and key bindings. Previously, when IDLE was started from a console or by import, a cascade of warnings was emitted. Patch by Serhiy Storchaka.

C API

bpo-28808 [https://bugs.python.org/issue?@action=redirect&bpo=28808]: PyUnicode_CompareWithASCIIString() now never raises exceptions.

bpo-26754 [https://bugs.python.org/issue?@action=redirect&bpo=26754]: PyUnicode_FSDecoder() accepted a filename argument encoded as an iterable of integers. Now only strings and bytes-like objects are accepted.

Documentation

bpo-28513 [https://bugs.python.org/issue?@action=redirect&bpo=28513]: Documented command-line interface of zipfile.

Tests

bpo-28950 [https://bugs.python.org/issue?@action=redirect&bpo=28950]: Disallow -j0 to be combined with -T/-l/-M in regrtest command line arguments.

bpo-28666 [https://bugs.python.org/issue?@action=redirect&bpo=28666]: Now test.support.rmtree is able to remove unwritable or unreadable directories.

bpo-23839 [https://bugs.python.org/issue?@action=redirect&bpo=23839]: Various caches now are cleared before running every test file.

bpo-28409 [https://bugs.python.org/issue?@action=redirect&bpo=28409]: regrtest: fix the parser of command line arguments.

bpo-27787 [https://bugs.python.org/issue?@action=redirect&bpo=27787]: Call gc.collect() before checking each test for “dangling threads”, since the dangling threads are weak references.

bpo-27369 [https://bugs.python.org/issue?@action=redirect&bpo=27369]: In test_pyexpat, avoid testing an error message detail that changed in Expat 2.2.0.

Tools/Demos

bpo-27952 [https://bugs.python.org/issue?@action=redirect&bpo=27952]: Get Tools/scripts/fixcid.py working with Python 3 and the current “re” module, avoid invalid Python backslash escapes, and fix a bug parsing escaped C quote signs.

bpo-27332 [https://bugs.python.org/issue?@action=redirect&bpo=27332]: Fixed the type of the first argument of module-level functions generated by Argument Clinic. Patch by Petr Viktorin.

bpo-27418 [https://bugs.python.org/issue?@action=redirect&bpo=27418]: Fixed Tools/importbench/importbench.py.

Windows

bpo-28251 [https://bugs.python.org/issue?@action=redirect&bpo=28251]: Improvements to help manuals on Windows.

bpo-28110 [https://bugs.python.org/issue?@action=redirect&bpo=28110]: launcher.msi has different product codes between 32-bit and 64-bit

bpo-25144 [https://bugs.python.org/issue?@action=redirect&bpo=25144]: Ensures TargetDir is set before continuing with custom install.

bpo-27469 [https://bugs.python.org/issue?@action=redirect&bpo=27469]: Adds a shell extension to the launcher so that drag and drop works correctly.

bpo-27309 [https://bugs.python.org/issue?@action=redirect&bpo=27309]: Enabled proper Windows styles in python[w].exe manifest.

Build

bpo-29080 [https://bugs.python.org/issue?@action=redirect&bpo=29080]: Removes hard dependency on hg.exe from PCBuild/build.bat

bpo-23903 [https://bugs.python.org/issue?@action=redirect&bpo=23903]: Added missed names to PC/python3.def.

bpo-10656 [https://bugs.python.org/issue?@action=redirect&bpo=10656]: Fix out-of-tree building on AIX. Patch by Tristan Carel and Michael Haubenwallner.

bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359]: Rename –with-optimiations to –enable-optimizations.

bpo-28444 [https://bugs.python.org/issue?@action=redirect&bpo=28444]: Fix missing extensions modules when cross compiling.

bpo-28248 [https://bugs.python.org/issue?@action=redirect&bpo=28248]: Update Windows build and OS X installers to use OpenSSL 1.0.2j.

bpo-28258 [https://bugs.python.org/issue?@action=redirect&bpo=28258]: Fixed build with Estonian locale (python-config and distclean targets in Makefile). Patch by Arfrever Frehtes Taifersar Arahesis.

bpo-26661 [https://bugs.python.org/issue?@action=redirect&bpo=26661]: setup.py now detects system libffi with multiarch wrapper.

bpo-28066 [https://bugs.python.org/issue?@action=redirect&bpo=28066]: Fix the logic that searches build directories for generated include files when building outside the source tree.

bpo-15819 [https://bugs.python.org/issue?@action=redirect&bpo=15819]: Remove redundant include search directory option for building outside the source tree.

bpo-27566 [https://bugs.python.org/issue?@action=redirect&bpo=27566]: Fix clean target in freeze makefile (patch by Lisa Roach)

bpo-27705 [https://bugs.python.org/issue?@action=redirect&bpo=27705]: Update message in validate_ucrtbase.py

bpo-27983 [https://bugs.python.org/issue?@action=redirect&bpo=27983]: Cause lack of llvm-profdata tool when using clang as required for PGO linking to be a configure time error rather than make time when –with-optimizations is enabled. Also improve our ability to find the llvm-profdata tool on MacOS and some Linuxes.

bpo-26307 [https://bugs.python.org/issue?@action=redirect&bpo=26307]: The profile-opt build now applies PGO to the built-in modules.

bpo-26359 [https://bugs.python.org/issue?@action=redirect&bpo=26359]: Add the –with-optimizations configure flag.

bpo-27713 [https://bugs.python.org/issue?@action=redirect&bpo=27713]: Suppress spurious build warnings when updating importlib’s bootstrap files. Patch by Xiang Zhang

bpo-25825 [https://bugs.python.org/issue?@action=redirect&bpo=25825]: Correct the references to Modules/python.exp and ld_so_aix, which are required on AIX. This updates references to an installation path that was changed in 3.2a4, and undoes changed references to the build tree that were made in 3.5.0a1.

bpo-27453 [https://bugs.python.org/issue?@action=redirect&bpo=27453]: CPP invocation in configure must use CPPFLAGS. Patch by Chi Hsuan Yen.

bpo-27641 [https://bugs.python.org/issue?@action=redirect&bpo=27641]: The configure script now inserts comments into the makefile to prevent the pgen and _freeze_importlib executables from being cross-compiled.

bpo-26662 [https://bugs.python.org/issue?@action=redirect&bpo=26662]: Set PYTHON_FOR_GEN in configure as the Python program to be used for file generation during the build.

bpo-10910 [https://bugs.python.org/issue?@action=redirect&bpo=10910]: Avoid C++ compilation errors on FreeBSD and OS X. Also update FreedBSD version checks for the original ctype UTF-8 workaround.

bpo-28676 [https://bugs.python.org/issue?@action=redirect&bpo=28676]: Prevent missing ‘getentropy’ declaration warning on macOS. Patch by Gareth Rees.

Python 3.5.2 final

Release date: 2016-06-26

Core and Builtins

bpo-26930 [https://bugs.python.org/issue?@action=redirect&bpo=26930]: Update Windows builds to use OpenSSL 1.0.2h.

Tests

bpo-26867 [https://bugs.python.org/issue?@action=redirect&bpo=26867]: Ubuntu’s openssl OP_NO_SSLv3 is forced on by default; fix test.

IDLE

bpo-27365 [https://bugs.python.org/issue?@action=redirect&bpo=27365]: Allow non-ascii in idlelib/NEWS.txt - minimal part for 3.5.2.

Python 3.5.2 release candidate 1

Release date: 2016-06-12

Security

bpo-26556 [https://bugs.python.org/issue?@action=redirect&bpo=26556]: Update expat to 2.1.1, fixes CVE 2015-1283 [https://www.cve.org/CVERecord?id=CVE-2015-1283].

Fix TLS stripping vulnerability in smtplib, CVE 2016-0772 [https://www.cve.org/CVERecord?id=CVE-2016-0772]. Reported by Team Oststrom.

bpo-26839 [https://bugs.python.org/issue?@action=redirect&bpo=26839]: On Linux, os.urandom() now calls getrandom() with GRND_NONBLOCK to fall back on reading /dev/urandom if the urandom entropy pool is not initialized yet. Patch written by Colm Buckley.

bpo-26657 [https://bugs.python.org/issue?@action=redirect&bpo=26657]: Fix directory traversal vulnerability with http.server on Windows. This fixes a regression that was introduced in 3.3.4rc1 and 3.4.0rc1. Based on patch by Philipp Hagemeister.

bpo-26313 [https://bugs.python.org/issue?@action=redirect&bpo=26313]: ssl.py _load_windows_store_certs fails if windows cert store is empty. Patch by Baji.

bpo-25939 [https://bugs.python.org/issue?@action=redirect&bpo=25939]: On Windows open the cert store readonly in ssl.enum_certificates.

Core and Builtins

bpo-27066 [https://bugs.python.org/issue?@action=redirect&bpo=27066]: Fixed SystemError if a custom opener (for open()) returns a negative number without setting an exception.

bpo-20041 [https://bugs.python.org/issue?@action=redirect&bpo=20041]: Fixed TypeError when frame.f_trace is set to None. Patch by Xavier de Gaye.

bpo-26168 [https://bugs.python.org/issue?@action=redirect&bpo=26168]: Fixed possible refleaks in failing Py_BuildValue() with the “N” format unit.

bpo-26991 [https://bugs.python.org/issue?@action=redirect&bpo=26991]: Fix possible refleak when creating a function with annotations.

bpo-27039 [https://bugs.python.org/issue?@action=redirect&bpo=27039]: Fixed bytearray.remove() for values greater than 127. Patch by Joe Jevnik.

bpo-23640 [https://bugs.python.org/issue?@action=redirect&bpo=23640]: int.from_bytes() no longer bypasses constructors for subclasses.

bpo-26811 [https://bugs.python.org/issue?@action=redirect&bpo=26811]: gc.get_objects() no longer contains a broken tuple with NULL pointer.

bpo-20120 [https://bugs.python.org/issue?@action=redirect&bpo=20120]: Use RawConfigParser for .pypirc parsing, removing support for interpolation unintentionally added with move to Python 3. Behavior no longer does any interpolation in .pypirc files, matching behavior in Python 2.7 and Setuptools 19.0.

bpo-26659 [https://bugs.python.org/issue?@action=redirect&bpo=26659]: Make the builtin slice type support cycle collection.

bpo-26718 [https://bugs.python.org/issue?@action=redirect&bpo=26718]: super.__init__ no longer leaks memory if called multiple times. NOTE: A direct call of super.__init__ is not endorsed!

bpo-25339 [https://bugs.python.org/issue?@action=redirect&bpo=25339]: PYTHONIOENCODING now has priority over locale in setting the error handler for stdin and stdout.

bpo-26494 [https://bugs.python.org/issue?@action=redirect&bpo=26494]: Fixed crash on iterating exhausting iterators. Affected classes are generic sequence iterators, iterators of str, bytes, bytearray, list, tuple, set, frozenset, dict, OrderedDict, corresponding views and os.scandir() iterator.

bpo-26581 [https://bugs.python.org/issue?@action=redirect&bpo=26581]: If coding cookie is specified multiple times on a line in Python source code file, only the first one is taken to account.

bpo-26464 [https://bugs.python.org/issue?@action=redirect&bpo=26464]: Fix str.translate() when string is ASCII and first replacements removes character, but next replacement uses a non-ASCII character or a string longer than 1 character. Regression introduced in Python 3.5.0.

bpo-22836 [https://bugs.python.org/issue?@action=redirect&bpo=22836]: Ensure exception reports from PyErr_Display() and PyErr_WriteUnraisable() are sensible even when formatting them produces secondary errors. This affects the reports produced by sys.__excepthook__() and when __del__() raises an exception.

bpo-26302 [https://bugs.python.org/issue?@action=redirect&bpo=26302]: Correct behavior to reject comma as a legal character for cookie names.

bpo-4806 [https://bugs.python.org/issue?@action=redirect&bpo=4806]: Avoid masking the original TypeError exception when using star (*) unpacking in function calls. Based on patch by Hagen Fürstenau and Daniel Urban.

bpo-27138 [https://bugs.python.org/issue?@action=redirect&bpo=27138]: Fix the doc comment for FileFinder.find_spec().

bpo-26154 [https://bugs.python.org/issue?@action=redirect&bpo=26154]: Add a new private _PyThreadState_UncheckedGet() function to get the current Python thread state, but don’t issue a fatal error if it is NULL. This new function must be used instead of accessing directly the _PyThreadState_Current variable. The variable is no more exposed since Python 3.5.1 to hide the exact implementation of atomic C types, to avoid compiler issues.

bpo-26194 [https://bugs.python.org/issue?@action=redirect&bpo=26194]: Deque.insert() gave odd results for bounded deques that had reached their maximum size. Now an IndexError will be raised when attempting to insert into a full deque.

bpo-25843 [https://bugs.python.org/issue?@action=redirect&bpo=25843]: When compiling code, don’t merge constants if they are equal but have a different types. For example, f1, f2 = lambda: 1, lambda: 1.0 is now correctly compiled to two different functions: f1() returns 1 (int) and f2() returns 1.0 (int), even if 1 and 1.0 are equal.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: [UPDATE] Comment out the one of the pickleability tests in _PyObject_GetState() due to regressions observed in Cython-based projects.

bpo-25961 [https://bugs.python.org/issue?@action=redirect&bpo=25961]: Disallowed null characters in the type name.

bpo-25973 [https://bugs.python.org/issue?@action=redirect&bpo=25973]: Fix segfault when an invalid nonlocal statement binds a name starting with two underscores.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: Instances of extension types with a state that aren’t subclasses of list or dict and haven’t implemented any pickle-related methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__, or __getstate__), can no longer be pickled. Including memoryview.

bpo-20440 [https://bugs.python.org/issue?@action=redirect&bpo=20440]: Massive replacing unsafe attribute setting code with special macro Py_SETREF.

bpo-25766 [https://bugs.python.org/issue?@action=redirect&bpo=25766]: Special method __bytes__() now works in str subclasses.

bpo-25421 [https://bugs.python.org/issue?@action=redirect&bpo=25421]: __sizeof__ methods of builtin types now use dynamic basic size. This allows sys.getsize() to work correctly with their subclasses with __slots__ defined.

bpo-25709 [https://bugs.python.org/issue?@action=redirect&bpo=25709]: Fixed problem with in-place string concatenation and utf-8 cache.

bpo-27147 [https://bugs.python.org/issue?@action=redirect&bpo=27147]: Mention PEP 420 [https://peps.python.org/pep-0420/] in the importlib docs.

bpo-24097 [https://bugs.python.org/issue?@action=redirect&bpo=24097]: Fixed crash in object.__reduce__() if slot name is freed inside __getattr__.

bpo-24731 [https://bugs.python.org/issue?@action=redirect&bpo=24731]: Fixed crash on converting objects with special methods __bytes__, __trunc__, and __float__ returning instances of subclasses of bytes, int, and float to subclasses of bytes, int, and float correspondingly.

bpo-26478 [https://bugs.python.org/issue?@action=redirect&bpo=26478]: Fix semantic bugs when using binary operators with dictionary views and tuples.

bpo-26171 [https://bugs.python.org/issue?@action=redirect&bpo=26171]: Fix possible integer overflow and heap corruption in zipimporter.get_data().

bpo-25660 [https://bugs.python.org/issue?@action=redirect&bpo=25660]: Fix TAB key behaviour in REPL with readline.

bpo-25887 [https://bugs.python.org/issue?@action=redirect&bpo=25887]: Raise a RuntimeError when a coroutine object is awaited more than once.

bpo-27243 [https://bugs.python.org/issue?@action=redirect&bpo=27243]: Update the __aiter__ protocol: instead of returning an awaitable that resolves to an asynchronous iterator, the asynchronous iterator should be returned directly. Doing the former will trigger a PendingDeprecationWarning.

Library

bpo-21386 [https://bugs.python.org/issue?@action=redirect&bpo=21386]: Implement missing IPv4Address.is_global property. It was documented since 07a5610bae9d. Initial patch by Roger Luethi.

bpo-20900 [https://bugs.python.org/issue?@action=redirect&bpo=20900]: distutils register command now decodes HTTP responses correctly. Initial patch by ingrid.

A new version of typing.py provides several new classes and features: @overload outside stubs, Reversible, DefaultDict, Text, ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug fixes (note that some of the new features are not yet implemented in mypy or other static analyzers). Also classes for PEP 492 [https://peps.python.org/pep-0492/] (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact they made it into 3.5.1 but were never mentioned).

bpo-25738 [https://bugs.python.org/issue?@action=redirect&bpo=25738]: Stop http.server.BaseHTTPRequestHandler.send_error() from sending a message body for 205 Reset Content. Also, don’t send Content header fields in responses that don’t have a body. Patch by Susumu Koshiba.

bpo-21313 [https://bugs.python.org/issue?@action=redirect&bpo=21313]: Fix the “platform” module to tolerate when sys.version contains truncated build information.

bpo-27164 [https://bugs.python.org/issue?@action=redirect&bpo=27164]: In the zlib module, allow decompressing raw Deflate streams with a predefined zdict. Based on patch by Xiang Zhang.

bpo-24291 [https://bugs.python.org/issue?@action=redirect&bpo=24291]: Fix wsgiref.simple_server.WSGIRequestHandler to completely write data to the client. Previously it could do partial writes and truncate data. Also, wsgiref.handler.ServerHandler can now handle stdout doing partial writes, but this is deprecated.

bpo-26809 [https://bugs.python.org/issue?@action=redirect&bpo=26809]: Add __all__ to string. Patch by Emanuel Barry.

bpo-26373 [https://bugs.python.org/issue?@action=redirect&bpo=26373]: subprocess.Popen.communicate now correctly ignores BrokenPipeError when the child process dies before .communicate() is called in more/all circumstances.

bpo-21776 [https://bugs.python.org/issue?@action=redirect&bpo=21776]: distutils.upload now correctly handles HTTPError. Initial patch by Claudiu Popa.

bpo-27114 [https://bugs.python.org/issue?@action=redirect&bpo=27114]: Fix SSLContext._load_windows_store_certs fails with PermissionError

bpo-18383 [https://bugs.python.org/issue?@action=redirect&bpo=18383]: Avoid creating duplicate filters when using filterwarnings and simplefilter. Based on patch by Alex Shkop.

bpo-27057 [https://bugs.python.org/issue?@action=redirect&bpo=27057]: Fix os.set_inheritable() on Android, ioctl() is blocked by SELinux and fails with EACCESS. The function now falls back to fcntl(). Patch written by Michał Bednarski.

bpo-27014 [https://bugs.python.org/issue?@action=redirect&bpo=27014]: Fix infinite recursion using typing.py. Thanks to Kalle Tuure!

bpo-14132 [https://bugs.python.org/issue?@action=redirect&bpo=14132]: Fix urllib.request redirect handling when the target only has a query string. Original fix by Ján Janech.

bpo-17214 [https://bugs.python.org/issue?@action=redirect&bpo=17214]: The “urllib.request” module now percent-encodes non-ASCII bytes found in redirect target URLs. Some servers send Location header fields with non-ASCII bytes, but “http.client” requires the request target to be ASCII-encodable, otherwise a UnicodeEncodeError is raised. Based on patch by Christian Heimes.

bpo-26892 [https://bugs.python.org/issue?@action=redirect&bpo=26892]: Honor debuglevel flag in urllib.request.HTTPHandler. Patch contributed by Chi Hsuan Yen.

bpo-22274 [https://bugs.python.org/issue?@action=redirect&bpo=22274]: In the subprocess module, allow stderr to be redirected to stdout even when stdout is not redirected. Patch by Akira Li.

bpo-26807 [https://bugs.python.org/issue?@action=redirect&bpo=26807]: mock_open ‘files’ no longer error on readline at end of file. Patch from Yolanda Robla.

bpo-25745 [https://bugs.python.org/issue?@action=redirect&bpo=25745]: Fixed leaking a userptr in curses panel destructor.

bpo-26977 [https://bugs.python.org/issue?@action=redirect&bpo=26977]: Removed unnecessary, and ignored, call to sum of squares helper in statistics.pvariance.

bpo-26881 [https://bugs.python.org/issue?@action=redirect&bpo=26881]: The modulefinder module now supports extended opcode arguments.

bpo-23815 [https://bugs.python.org/issue?@action=redirect&bpo=23815]: Fixed crashes related to directly created instances of types in _tkinter and curses.panel modules.

bpo-17765 [https://bugs.python.org/issue?@action=redirect&bpo=17765]: weakref.ref() no longer silently ignores keyword arguments. Patch by Georg Brandl.

bpo-26873 [https://bugs.python.org/issue?@action=redirect&bpo=26873]: xmlrpc now raises ResponseError on unsupported type tags instead of silently return incorrect result.

bpo-26711 [https://bugs.python.org/issue?@action=redirect&bpo=26711]: Fixed the comparison of plistlib.Data with other types.

bpo-24114 [https://bugs.python.org/issue?@action=redirect&bpo=24114]: Fix an uninitialized variable in ctypes.util. The bug only occurs on SunOS when the ctypes implementation searches for the crle program. Patch by Xiang Zhang. Tested on SunOS by Kees Bos.

bpo-26864 [https://bugs.python.org/issue?@action=redirect&bpo=26864]: In urllib.request, change the proxy bypass host checking against no_proxy to be case-insensitive, and to not match unrelated host names that happen to have a bypassed hostname as a suffix. Patch by Xiang Zhang.

bpo-26634 [https://bugs.python.org/issue?@action=redirect&bpo=26634]: recursive_repr() now sets __qualname__ of wrapper. Patch by Xiang Zhang.

bpo-26804 [https://bugs.python.org/issue?@action=redirect&bpo=26804]: urllib.request will prefer lower_case proxy environment variables over UPPER_CASE or Mixed_Case ones. Patch contributed by Hans-Peter Jansen.

bpo-26837 [https://bugs.python.org/issue?@action=redirect&bpo=26837]: assertSequenceEqual() now correctly outputs non-stringified differing items (like bytes in the -b mode). This affects assertListEqual() and assertTupleEqual().

bpo-26041 [https://bugs.python.org/issue?@action=redirect&bpo=26041]: Remove “will be removed in Python 3.7” from deprecation messages of platform.dist() and platform.linux_distribution(). Patch by Kumaripaba Miyurusara Athukorala.

bpo-26822 [https://bugs.python.org/issue?@action=redirect&bpo=26822]: itemgetter, attrgetter and methodcaller objects no longer silently ignore keyword arguments.

bpo-26733 [https://bugs.python.org/issue?@action=redirect&bpo=26733]: Disassembling a class now disassembles class and static methods. Patch by Xiang Zhang.

bpo-26801 [https://bugs.python.org/issue?@action=redirect&bpo=26801]: Fix error handling in shutil.get_terminal_size(), catch AttributeError instead of NameError. Patch written by Emanuel Barry.

bpo-24838 [https://bugs.python.org/issue?@action=redirect&bpo=24838]: tarfile’s ustar and gnu formats now correctly calculate name and link field limits for multibyte character encodings like utf-8.

bpo-26717 [https://bugs.python.org/issue?@action=redirect&bpo=26717]: Stop encoding Latin-1-ized WSGI paths with UTF-8. Patch by Anthony Sottile.

bpo-26735 [https://bugs.python.org/issue?@action=redirect&bpo=26735]: Fix os.urandom() on Solaris 11.3 and newer when reading more than 1,024 bytes: call getrandom() multiple times with a limit of 1024 bytes per call.

bpo-16329 [https://bugs.python.org/issue?@action=redirect&bpo=16329]: Add .webm to mimetypes.types_map. Patch by Giampaolo Rodola’.

bpo-13952 [https://bugs.python.org/issue?@action=redirect&bpo=13952]: Add .csv to mimetypes.types_map. Patch by Geoff Wilson.

bpo-26709 [https://bugs.python.org/issue?@action=redirect&bpo=26709]: Fixed Y2038 problem in loading binary PLists.

bpo-23735 [https://bugs.python.org/issue?@action=redirect&bpo=23735]: Handle terminal resizing with Readline 6.3+ by installing our own SIGWINCH handler. Patch by Eric Price.

bpo-26586 [https://bugs.python.org/issue?@action=redirect&bpo=26586]: In http.server, respond with “413 Request header fields too large” if there are too many header fields to parse, rather than killing the connection and raising an unhandled exception. Patch by Xiang Zhang.

bpo-22854 [https://bugs.python.org/issue?@action=redirect&bpo=22854]: Change BufferedReader.writable() and BufferedWriter.readable() to always return False.

bpo-25195 [https://bugs.python.org/issue?@action=redirect&bpo=25195]: Fix a regression in mock.MagicMock. _Call is a subclass of tuple (changeset 3603bae63c13 only works for classes) so we need to implement __ne__ ourselves. Patch by Andrew Plummer.

bpo-26644 [https://bugs.python.org/issue?@action=redirect&bpo=26644]: Raise ValueError rather than SystemError when a negative length is passed to SSLSocket.recv() or read().

bpo-23804 [https://bugs.python.org/issue?@action=redirect&bpo=23804]: Fix SSL recv(0) and read(0) methods to return zero bytes instead of up to 1024.

bpo-26616 [https://bugs.python.org/issue?@action=redirect&bpo=26616]: Fixed a bug in datetime.astimezone() method.

bpo-21925 [https://bugs.python.org/issue?@action=redirect&bpo=21925]: warnings.formatwarning() now catches exceptions on linecache.getline(...) to be able to log ResourceWarning emitted late during the Python shutdown process.

bpo-24266 [https://bugs.python.org/issue?@action=redirect&bpo=24266]: Ctrl+C during Readline history search now cancels the search mode when compiled with Readline 7.

bpo-26560 [https://bugs.python.org/issue?@action=redirect&bpo=26560]: Avoid potential ValueError in BaseHandler.start_response. Initial patch by Peter Inglesby.

bpo-26569 [https://bugs.python.org/issue?@action=redirect&bpo=26569]: Fix pyclbr.readmodule() and pyclbr.readmodule_ex() to support importing packages.

bpo-26499 [https://bugs.python.org/issue?@action=redirect&bpo=26499]: Account for remaining Content-Length in HTTPResponse.readline() and read1(). Based on patch by Silent Ghost. Also document that HTTPResponse now supports these methods.

bpo-25320 [https://bugs.python.org/issue?@action=redirect&bpo=25320]: Handle sockets in directories unittest discovery is scanning. Patch from Victor van den Elzen.

bpo-16181 [https://bugs.python.org/issue?@action=redirect&bpo=16181]: cookiejar.http2time() now returns None if year is higher than datetime.MAXYEAR.

bpo-26513 [https://bugs.python.org/issue?@action=redirect&bpo=26513]: Fixes platform module detection of Windows Server

bpo-23718 [https://bugs.python.org/issue?@action=redirect&bpo=23718]: Fixed parsing time in week 0 before Jan 1. Original patch by Tamás Bence Gedai.

bpo-20589 [https://bugs.python.org/issue?@action=redirect&bpo=20589]: Invoking Path.owner() and Path.group() on Windows now raise NotImplementedError instead of ImportError.

bpo-26177 [https://bugs.python.org/issue?@action=redirect&bpo=26177]: Fixed the keys() method for Canvas and Scrollbar widgets.

bpo-15068 [https://bugs.python.org/issue?@action=redirect&bpo=15068]: Got rid of excessive buffering in the fileinput module. The bufsize parameter is no longer used.

bpo-2202 [https://bugs.python.org/issue?@action=redirect&bpo=2202]: Fix UnboundLocalError in AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by Mathieu Dupuy.

bpo-25718 [https://bugs.python.org/issue?@action=redirect&bpo=25718]: Fixed pickling and copying the accumulate() iterator with total is None.

bpo-26475 [https://bugs.python.org/issue?@action=redirect&bpo=26475]: Fixed debugging output for regular expressions with the (?x) flag.

bpo-26457 [https://bugs.python.org/issue?@action=redirect&bpo=26457]: Fixed the subnets() methods in IP network classes for the case when resulting prefix length is equal to maximal prefix length. Based on patch by Xiang Zhang.

bpo-26385 [https://bugs.python.org/issue?@action=redirect&bpo=26385]: Remove the file if the internal open() call in NamedTemporaryFile() fails. Patch by Silent Ghost.

bpo-26402 [https://bugs.python.org/issue?@action=redirect&bpo=26402]: Fix XML-RPC client to retry when the server shuts down a persistent connection. This was a regression related to the new http.client.RemoteDisconnected exception in 3.5.0a4.

bpo-25913 [https://bugs.python.org/issue?@action=redirect&bpo=25913]: Leading <~ is optional now in base64.a85decode() with adobe=True. Patch by Swati Jaiswal.

bpo-26186 [https://bugs.python.org/issue?@action=redirect&bpo=26186]: Remove an invalid type check in importlib.util.LazyLoader.

bpo-26367 [https://bugs.python.org/issue?@action=redirect&bpo=26367]: importlib.__import__() raises SystemError like builtins.__import__() when level is specified but without an accompanying package specified.

bpo-26309 [https://bugs.python.org/issue?@action=redirect&bpo=26309]: In the “socketserver” module, shut down the request (closing the connected socket) when verify_request() returns false. Patch by Aviv Palivoda.

bpo-25995 [https://bugs.python.org/issue?@action=redirect&bpo=25995]: os.walk() no longer uses FDs proportional to the tree depth.

bpo-26117 [https://bugs.python.org/issue?@action=redirect&bpo=26117]: The os.scandir() iterator now closes file descriptor not only when the iteration is finished, but when it was failed with error.

bpo-25911 [https://bugs.python.org/issue?@action=redirect&bpo=25911]: Restored support of bytes paths in os.walk() on Windows.

bpo-26045 [https://bugs.python.org/issue?@action=redirect&bpo=26045]: Add UTF-8 suggestion to error message when posting a non-Latin-1 string with http.client.

bpo-12923 [https://bugs.python.org/issue?@action=redirect&bpo=12923]: Reset FancyURLopener’s redirect counter even if there is an exception. Based on patches by Brian Brazil and Daniel Rocco.

bpo-25945 [https://bugs.python.org/issue?@action=redirect&bpo=25945]: Fixed a crash when unpickle the functools.partial object with wrong state. Fixed a leak in failed functools.partial constructor. “args” and “keywords” attributes of functools.partial have now always types tuple and dict correspondingly.

bpo-26202 [https://bugs.python.org/issue?@action=redirect&bpo=26202]: copy.deepcopy() now correctly copies range() objects with non-atomic attributes.

bpo-23076 [https://bugs.python.org/issue?@action=redirect&bpo=23076]: Path.glob() now raises a ValueError if it’s called with an invalid pattern. Patch by Thomas Nyberg.

bpo-19883 [https://bugs.python.org/issue?@action=redirect&bpo=19883]: Fixed possible integer overflows in zipimport.

bpo-26227 [https://bugs.python.org/issue?@action=redirect&bpo=26227]: On Windows, getnameinfo(), gethostbyaddr() and gethostbyname_ex() functions of the socket module now decode the hostname from the ANSI code page rather than UTF-8.

bpo-26147 [https://bugs.python.org/issue?@action=redirect&bpo=26147]: xmlrpc now works with strings not encodable with used non-UTF-8 encoding.

bpo-25935 [https://bugs.python.org/issue?@action=redirect&bpo=25935]: Garbage collector now breaks reference loops with OrderedDict.

bpo-16620 [https://bugs.python.org/issue?@action=redirect&bpo=16620]: Fixed AttributeError in msilib.Directory.glob().

bpo-26013 [https://bugs.python.org/issue?@action=redirect&bpo=26013]: Added compatibility with broken protocol 2 pickles created in old Python 3 versions (3.4.3 and lower).

bpo-25850 [https://bugs.python.org/issue?@action=redirect&bpo=25850]: Use cross-compilation by default for 64-bit Windows.

bpo-17633 [https://bugs.python.org/issue?@action=redirect&bpo=17633]: Improve zipimport’s support for namespace packages.

bpo-24705 [https://bugs.python.org/issue?@action=redirect&bpo=24705]: Fix sysconfig._parse_makefile not expanding ${} vars appearing before $() vars.

bpo-22138 [https://bugs.python.org/issue?@action=redirect&bpo=22138]: Fix mock.patch behavior when patching descriptors. Restore original values after patching. Patch contributed by Sean McCully.

bpo-25672 [https://bugs.python.org/issue?@action=redirect&bpo=25672]: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS mode option if it is safe to do so.

bpo-26012 [https://bugs.python.org/issue?@action=redirect&bpo=26012]: Don’t traverse into symlinks for ** pattern in pathlib.Path.[r]glob().

bpo-24120 [https://bugs.python.org/issue?@action=redirect&bpo=24120]: Ignore PermissionError when traversing a tree with pathlib.Path.[r]glob(). Patch by Ulrich Petri.

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: fileinput now uses sys.stdin as-is if it does not have a buffer attribute (restores backward compatibility).

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: Copying the lru_cache() wrapper object now always works, independently from the type of the wrapped object (by returning the original object unchanged).

bpo-24103 [https://bugs.python.org/issue?@action=redirect&bpo=24103]: Fixed possible use after free in ElementTree.XMLPullParser.

bpo-25860 [https://bugs.python.org/issue?@action=redirect&bpo=25860]: os.fwalk() no longer skips remaining directories when error occurs. Original patch by Samson Lee.

bpo-25914 [https://bugs.python.org/issue?@action=redirect&bpo=25914]: Fixed and simplified OrderedDict.__sizeof__.

bpo-25902 [https://bugs.python.org/issue?@action=redirect&bpo=25902]: Fixed various refcount issues in ElementTree iteration.

bpo-25717 [https://bugs.python.org/issue?@action=redirect&bpo=25717]: Restore the previous behaviour of tolerating most fstat() errors when opening files. This was a regression in 3.5a1, and stopped anonymous temporary files from working in special cases.

bpo-24903 [https://bugs.python.org/issue?@action=redirect&bpo=24903]: Fix regression in number of arguments compileall accepts when ‘-d’ is specified. The check on the number of arguments has been dropped completely as it never worked correctly anyway.

bpo-25764 [https://bugs.python.org/issue?@action=redirect&bpo=25764]: In the subprocess module, preserve any exception caused by fork() failure when preexec_fn is used.

bpo-6478 [https://bugs.python.org/issue?@action=redirect&bpo=6478]: _strptime’s regexp cache now is reset after changing timezone with time.tzset().

bpo-14285 [https://bugs.python.org/issue?@action=redirect&bpo=14285]: When executing a package with the “python -m package” option, and package initialization fails, a proper traceback is now reported. The “runpy” module now lets exceptions from package initialization pass back to the caller, rather than raising ImportError.

bpo-19771 [https://bugs.python.org/issue?@action=redirect&bpo=19771]: Also in runpy and the “-m” option, omit the irrelevant message “… is a package and cannot be directly executed” if the package could not even be initialized (e.g. due to a bad *.pyc file).

bpo-25177 [https://bugs.python.org/issue?@action=redirect&bpo=25177]: Fixed problem with the mean of very small and very large numbers. As a side effect, statistics.mean and statistics.variance should be significantly faster.

bpo-25718 [https://bugs.python.org/issue?@action=redirect&bpo=25718]: Fixed copying object with state with boolean value is false.

bpo-10131 [https://bugs.python.org/issue?@action=redirect&bpo=10131]: Fixed deep copying of minidom documents. Based on patch by Marian Ganisin.

bpo-25725 [https://bugs.python.org/issue?@action=redirect&bpo=25725]: Fixed a reference leak in pickle.loads() when unpickling invalid data including tuple instructions.

bpo-25663 [https://bugs.python.org/issue?@action=redirect&bpo=25663]: In the Readline completer, avoid listing duplicate global names, and search the global namespace before searching builtins.

bpo-25688 [https://bugs.python.org/issue?@action=redirect&bpo=25688]: Fixed file leak in ElementTree.iterparse() raising an error.

bpo-23914 [https://bugs.python.org/issue?@action=redirect&bpo=23914]: Fixed SystemError raised by unpickler on broken pickle data.

bpo-25691 [https://bugs.python.org/issue?@action=redirect&bpo=25691]: Fixed crash on deleting ElementTree.Element attributes.

bpo-25624 [https://bugs.python.org/issue?@action=redirect&bpo=25624]: ZipFile now always writes a ZIP_STORED header for directory entries. Patch by Dingyuan Wang.

Skip getaddrinfo if host is already resolved. Patch by A. Jesse Jiryu Davis.

bpo-26050 [https://bugs.python.org/issue?@action=redirect&bpo=26050]: Add asyncio.StreamReader.readuntil() method. Patch by Марк Коренберг.

bpo-25924 [https://bugs.python.org/issue?@action=redirect&bpo=25924]: Avoid unnecessary serialization of getaddrinfo(3) calls on OS X versions 10.5 or higher. Original patch by A. Jesse Jiryu Davis.

bpo-26406 [https://bugs.python.org/issue?@action=redirect&bpo=26406]: Avoid unnecessary serialization of getaddrinfo(3) calls on current versions of OpenBSD and NetBSD. Patch by A. Jesse Jiryu Davis.

bpo-26848 [https://bugs.python.org/issue?@action=redirect&bpo=26848]: Fix asyncio/subprocess.communicate() to handle empty input. Patch by Jack O’Connor.

bpo-27040 [https://bugs.python.org/issue?@action=redirect&bpo=27040]: Add loop.get_exception_handler method

bpo-27041 [https://bugs.python.org/issue?@action=redirect&bpo=27041]: asyncio: Add loop.create_future method

bpo-27223 [https://bugs.python.org/issue?@action=redirect&bpo=27223]: asyncio: Fix _read_ready and _write_ready to respect _conn_lost. Patch by Łukasz Langa.

bpo-22970 [https://bugs.python.org/issue?@action=redirect&bpo=22970]: asyncio: Fix inconsistency cancelling Condition.wait. Patch by David Coles.

IDLE

bpo-5124 [https://bugs.python.org/issue?@action=redirect&bpo=5124]: Paste with text selected now replaces the selection on X11. This matches how paste works on Windows, Mac, most modern Linux apps, and ttk widgets. Original patch by Serhiy Storchaka.

bpo-24759 [https://bugs.python.org/issue?@action=redirect&bpo=24759]: Make clear in idlelib.idle_test.__init__ that the directory is a private implementation of test.test_idle and tool for maintainers.

bpo-27196 [https://bugs.python.org/issue?@action=redirect&bpo=27196]: Stop ‘ThemeChanged’ warnings when running IDLE tests. These persisted after other warnings were suppressed in #20567. Apply Serhiy Storchaka’s update_idletasks solution to four test files. Record this additional advice in idle_test/README.txt

bpo-20567 [https://bugs.python.org/issue?@action=redirect&bpo=20567]: Revise idle_test/README.txt with advice about avoiding tk warning messages from tests. Apply advice to several IDLE tests.

bpo-27117 [https://bugs.python.org/issue?@action=redirect&bpo=27117]: Make colorizer htest and turtledemo work with dark themes. Move code for configuring text widget colors to a new function.

bpo-26673 [https://bugs.python.org/issue?@action=redirect&bpo=26673]: When tk reports font size as 0, change to size 10. Such fonts on Linux prevented the configuration dialog from opening.

bpo-21939 [https://bugs.python.org/issue?@action=redirect&bpo=21939]: Add test for IDLE’s percolator. Original patch by Saimadhav Heblikar.

bpo-21676 [https://bugs.python.org/issue?@action=redirect&bpo=21676]: Add test for IDLE’s replace dialog. Original patch by Saimadhav Heblikar.

bpo-18410 [https://bugs.python.org/issue?@action=redirect&bpo=18410]: Add test for IDLE’s search dialog. Original patch by Westley Martínez.

bpo-21703 [https://bugs.python.org/issue?@action=redirect&bpo=21703]: Add test for IDLE’s undo delegator. Original patch by Saimadhav Heblikar .

bpo-27044 [https://bugs.python.org/issue?@action=redirect&bpo=27044]: Add ConfigDialog.remove_var_callbacks to stop memory leaks.

bpo-23977 [https://bugs.python.org/issue?@action=redirect&bpo=23977]: Add more asserts to test_delegator.

bpo-20640 [https://bugs.python.org/issue?@action=redirect&bpo=20640]: Add tests for idlelib.configHelpSourceEdit. Patch by Saimadhav Heblikar.

In the ‘IDLE-console differences’ section of the IDLE doc, clarify how running with IDLE affects sys.modules and the standard streams.

bpo-25507 [https://bugs.python.org/issue?@action=redirect&bpo=25507]: fix incorrect change in IOBinding that prevented printing. Augment IOBinding htest to include all major IOBinding functions.

bpo-25905 [https://bugs.python.org/issue?@action=redirect&bpo=25905]: Revert unwanted conversion of ‘ to ’ RIGHT SINGLE QUOTATION MARK in README.txt and open this and NEWS.txt with ‘ascii’. Re-encode CREDITS.txt to utf-8 and open it with ‘utf-8’.

Documentation

bpo-19489 [https://bugs.python.org/issue?@action=redirect&bpo=19489]: Moved the search box from the sidebar to the header and footer of each page. Patch by Ammar Askar.

bpo-24136 [https://bugs.python.org/issue?@action=redirect&bpo=24136]: Document the new PEP 448 [https://peps.python.org/pep-0448/] unpacking syntax of 3.5.

bpo-26736 [https://bugs.python.org/issue?@action=redirect&bpo=26736]: Used HTTPS for external links in the documentation if possible.

bpo-6953 [https://bugs.python.org/issue?@action=redirect&bpo=6953]: Rework the Readline module documentation to group related functions together, and add more details such as what underlying Readline functions and variables are accessed.

bpo-23606 [https://bugs.python.org/issue?@action=redirect&bpo=23606]: Adds note to ctypes documentation regarding cdll.msvcrt.

bpo-25500 [https://bugs.python.org/issue?@action=redirect&bpo=25500]: Fix documentation to not claim that __import__ is searched for in the global scope.

bpo-26014 [https://bugs.python.org/issue?@action=redirect&bpo=26014]: Update 3.x packaging documentation: * “See also” links to the new docs are now provided in the legacy pages * links to setuptools documentation have been updated

Tests

bpo-21916 [https://bugs.python.org/issue?@action=redirect&bpo=21916]: Added tests for the turtle module. Patch by ingrid, Gregory Loyse and Jelle Zijlstra.

bpo-26523 [https://bugs.python.org/issue?@action=redirect&bpo=26523]: The multiprocessing thread pool (multiprocessing.dummy.Pool) was untested.

bpo-26015 [https://bugs.python.org/issue?@action=redirect&bpo=26015]: Added new tests for pickling iterators of mutable sequences.

bpo-26325 [https://bugs.python.org/issue?@action=redirect&bpo=26325]: Added test.support.check_no_resource_warning() to check that no ResourceWarning is emitted.

bpo-25940 [https://bugs.python.org/issue?@action=redirect&bpo=25940]: Changed test_ssl to use self-signed.pythontest.net. This avoids relying on svn.python.org, which recently changed root certificate.

bpo-25616 [https://bugs.python.org/issue?@action=redirect&bpo=25616]: Tests for OrderedDict are extracted from test_collections into separate file test_ordered_dict.

bpo-26583 [https://bugs.python.org/issue?@action=redirect&bpo=26583]: Skip test_timestamp_overflow in test_import if bytecode files cannot be written.

Build

bpo-26884 [https://bugs.python.org/issue?@action=redirect&bpo=26884]: Fix linking extension modules for cross builds. Patch by Xavier de Gaye.

bpo-22359 [https://bugs.python.org/issue?@action=redirect&bpo=22359]: Disable the rules for running _freeze_importlib and pgen when cross-compiling. The output of these programs is normally saved with the source code anyway, and is still regenerated when doing a native build. Patch by Xavier de Gaye.

bpo-27229 [https://bugs.python.org/issue?@action=redirect&bpo=27229]: Fix the cross-compiling pgen rule for in-tree builds. Patch by Xavier de Gaye.

bpo-21668 [https://bugs.python.org/issue?@action=redirect&bpo=21668]: Link audioop, _datetime, _ctypes_test modules to libm, except on Mac OS X. Patch written by Xavier de Gaye.

bpo-25702 [https://bugs.python.org/issue?@action=redirect&bpo=25702]: A –with-lto configure option has been added that will enable link time optimizations at build time during a make profile-opt. Some compilers and toolchains are known to not produce stable code when using LTO, be sure to test things thoroughly before relying on it. It can provide a few % speed up over profile-opt alone.

bpo-26624 [https://bugs.python.org/issue?@action=redirect&bpo=26624]: Adds validation of ucrtbase[d].dll version with warning for old versions.

bpo-17603 [https://bugs.python.org/issue?@action=redirect&bpo=17603]: Avoid error about nonexistent fileblocks.o file by using a lower-level check for st_blocks in struct stat.

bpo-26079 [https://bugs.python.org/issue?@action=redirect&bpo=26079]: Fixing the build output folder for tix-8.4.3.6. Patch by Bjoern Thiel.

bpo-26465 [https://bugs.python.org/issue?@action=redirect&bpo=26465]: Update Windows builds to use OpenSSL 1.0.2g.

bpo-24421 [https://bugs.python.org/issue?@action=redirect&bpo=24421]: Compile Modules/_math.c once, before building extensions. Previously it could fail to compile properly if the math and cmath builds were concurrent.

bpo-25348 [https://bugs.python.org/issue?@action=redirect&bpo=25348]: Added --pgo and --pgo-job arguments to PCbuild\build.bat for building with Profile-Guided Optimization. The old PCbuild\build_pgo.bat script is now deprecated, and simply calls PCbuild\build.bat --pgo %*.

bpo-25827 [https://bugs.python.org/issue?@action=redirect&bpo=25827]: Add support for building with ICC to configure, including a new --with-icc flag.

bpo-25696 [https://bugs.python.org/issue?@action=redirect&bpo=25696]: Fix installation of Python on UNIX with make -j9.

bpo-26930 [https://bugs.python.org/issue?@action=redirect&bpo=26930]: Update OS X 10.5+ 32-bit-only installer to build and link with OpenSSL 1.0.2h.

bpo-26268 [https://bugs.python.org/issue?@action=redirect&bpo=26268]: Update Windows builds to use OpenSSL 1.0.2f.

bpo-25136 [https://bugs.python.org/issue?@action=redirect&bpo=25136]: Support Apple Xcode 7’s new textual SDK stub libraries.

bpo-24324 [https://bugs.python.org/issue?@action=redirect&bpo=24324]: Do not enable unreachable code warnings when using gcc as the option does not work correctly in older versions of gcc and has been silently removed as of gcc-4.5.

Windows

bpo-27053 [https://bugs.python.org/issue?@action=redirect&bpo=27053]: Updates make_zip.py to correctly generate library ZIP file.

bpo-26268 [https://bugs.python.org/issue?@action=redirect&bpo=26268]: Update the prepare_ssl.py script to handle OpenSSL releases that don’t include the contents of the include directory (that is, 1.0.2e and later).

bpo-26071 [https://bugs.python.org/issue?@action=redirect&bpo=26071]: bdist_wininst created binaries fail to start and find 32bit Python

bpo-26073 [https://bugs.python.org/issue?@action=redirect&bpo=26073]: Update the list of magic numbers in launcher

bpo-26065 [https://bugs.python.org/issue?@action=redirect&bpo=26065]: Excludes venv from library when generating embeddable distro.

bpo-17500 [https://bugs.python.org/issue?@action=redirect&bpo=17500]: Remove unused and outdated icons. (See also: https://github.com/python/pythondotorg/issues/945)

Tools/Demos

bpo-26799 [https://bugs.python.org/issue?@action=redirect&bpo=26799]: Fix python-gdb.py: don’t get C types once when the Python code is loaded, but get C types on demand. The C types can change if python-gdb.py is loaded before the Python executable. Patch written by Thomas Ilsche.

bpo-26271 [https://bugs.python.org/issue?@action=redirect&bpo=26271]: Fix the Freeze tool to properly use flags passed through configure. Patch by Daniel Shaulov.

bpo-26489 [https://bugs.python.org/issue?@action=redirect&bpo=26489]: Add dictionary unpacking support to Tools/parser/unparse.py. Patch by Guo Ci Teo.

bpo-26316 [https://bugs.python.org/issue?@action=redirect&bpo=26316]: Fix variable name typo in Argument Clinic.

Python 3.5.1 final

Release date: 2015-12-06

Core and Builtins

bpo-25709 [https://bugs.python.org/issue?@action=redirect&bpo=25709]: Fixed problem with in-place string concatenation and utf-8 cache.

Windows

bpo-25715 [https://bugs.python.org/issue?@action=redirect&bpo=25715]: Python 3.5.1 installer shows wrong upgrade path and incorrect logic for launcher detection.

Python 3.5.1 release candidate 1

Release date: 2015-11-22

Core and Builtins

bpo-25630 [https://bugs.python.org/issue?@action=redirect&bpo=25630]: Fix a possible segfault during argument parsing in functions that accept filesystem paths.

bpo-23564 [https://bugs.python.org/issue?@action=redirect&bpo=23564]: Fixed a partially broken sanity check in the _posixsubprocess internals regarding how fds_to_pass were passed to the child. The bug had no actual impact as subprocess.py already avoided it.

bpo-25388 [https://bugs.python.org/issue?@action=redirect&bpo=25388]: Fixed tokenizer crash when processing undecodable source code with a null byte.

bpo-25462 [https://bugs.python.org/issue?@action=redirect&bpo=25462]: The hash of the key now is calculated only once in most operations in C implementation of OrderedDict.

bpo-22995 [https://bugs.python.org/issue?@action=redirect&bpo=22995]: Default implementation of __reduce__ and __reduce_ex__ now rejects builtin types with not defined __new__.

bpo-25555 [https://bugs.python.org/issue?@action=redirect&bpo=25555]: Fix parser and AST: fill lineno and col_offset of “arg” node when compiling AST from Python objects.

bpo-24802 [https://bugs.python.org/issue?@action=redirect&bpo=24802]: Avoid buffer overreads when int(), float(), compile(), exec() and eval() are passed bytes-like objects. These objects are not necessarily terminated by a null byte, but the functions assumed they were.

bpo-24726 [https://bugs.python.org/issue?@action=redirect&bpo=24726]: Fixed a crash and leaking NULL in repr() of OrderedDict that was mutated by direct calls of dict methods.

bpo-25449 [https://bugs.python.org/issue?@action=redirect&bpo=25449]: Iterating OrderedDict with keys with unstable hash now raises KeyError in C implementations as well as in Python implementation.

bpo-25395 [https://bugs.python.org/issue?@action=redirect&bpo=25395]: Fixed crash when highly nested OrderedDict structures were garbage collected.

bpo-25274 [https://bugs.python.org/issue?@action=redirect&bpo=25274]: sys.setrecursionlimit() now raises a RecursionError if the new recursion limit is too low depending at the current recursion depth. Modify also the “lower-water mark” formula to make it monotonic. This mark is used to decide when the overflowed flag of the thread state is reset.

bpo-24402 [https://bugs.python.org/issue?@action=redirect&bpo=24402]: Fix input() to prompt to the redirected stdout when sys.stdout.fileno() fails.

bpo-24806 [https://bugs.python.org/issue?@action=redirect&bpo=24806]: Prevent builtin types that are not allowed to be subclassed from being subclassed through multiple inheritance.

bpo-24848 [https://bugs.python.org/issue?@action=redirect&bpo=24848]: Fixed a number of bugs in UTF-7 decoding of misformed data.

bpo-25280 [https://bugs.python.org/issue?@action=redirect&bpo=25280]: Import trace messages emitted in verbose (-v) mode are no longer formatted twice.

bpo-25003 [https://bugs.python.org/issue?@action=redirect&bpo=25003]: On Solaris 11.3 or newer, os.urandom() now uses the getrandom() function instead of the getentropy() function. The getentropy() function is blocking to generate very good quality entropy, os.urandom() doesn’t need such high-quality entropy.

bpo-25182 [https://bugs.python.org/issue?@action=redirect&bpo=25182]: The stdprinter (used as sys.stderr before the io module is imported at startup) now uses the backslashreplace error handler.

bpo-25131 [https://bugs.python.org/issue?@action=redirect&bpo=25131]: Make the line number and column offset of set/dict literals and comprehensions correspond to the opening brace.

bpo-25150 [https://bugs.python.org/issue?@action=redirect&bpo=25150]: Hide the private _Py_atomic_xxx symbols from the public Python.h header to fix a compilation error with OpenMP. PyThreadState_GET() becomes an alias to PyThreadState_Get() to avoid ABI incompatibilities.

Library

bpo-25626 [https://bugs.python.org/issue?@action=redirect&bpo=25626]: Change three zlib functions to accept sizes that fit in Py_ssize_t, but internally cap those sizes to UINT_MAX. This resolves a regression in 3.5 where GzipFile.read() failed to read chunks larger than 2 or 4 GiB. The change affects the zlib.Decompress.decompress() max_length parameter, the zlib.decompress() bufsize parameter, and the zlib.Decompress.flush() length parameter.

bpo-25583 [https://bugs.python.org/issue?@action=redirect&bpo=25583]: Avoid incorrect errors raised by os.makedirs(exist_ok=True) when the OS gives priority to errors such as EACCES over EEXIST.

bpo-25593 [https://bugs.python.org/issue?@action=redirect&bpo=25593]: Change semantics of EventLoop.stop() in asyncio.

bpo-6973 [https://bugs.python.org/issue?@action=redirect&bpo=6973]: When we know a subprocess.Popen process has died, do not allow the send_signal(), terminate(), or kill() methods to do anything as they could potentially signal a different process.

bpo-25590 [https://bugs.python.org/issue?@action=redirect&bpo=25590]: In the Readline completer, only call getattr() once per attribute.

bpo-25498 [https://bugs.python.org/issue?@action=redirect&bpo=25498]: Fix a crash when garbage-collecting ctypes objects created by wrapping a memoryview. This was a regression made in 3.5a1. Based on patch by Eryksun.

bpo-25584 [https://bugs.python.org/issue?@action=redirect&bpo=25584]: Added “escape” to the __all__ list in the glob module.

bpo-25584 [https://bugs.python.org/issue?@action=redirect&bpo=25584]: Fixed recursive glob() with patterns starting with **.

bpo-25446 [https://bugs.python.org/issue?@action=redirect&bpo=25446]: Fix regression in smtplib’s AUTH LOGIN support.

bpo-18010 [https://bugs.python.org/issue?@action=redirect&bpo=18010]: Fix the pydoc web server’s module search function to handle exceptions from importing packages.

bpo-25554 [https://bugs.python.org/issue?@action=redirect&bpo=25554]: Got rid of circular references in regular expression parsing.

bpo-25510 [https://bugs.python.org/issue?@action=redirect&bpo=25510]: fileinput.FileInput.readline() now returns b’’ instead of ‘’ at the end if the FileInput was opened with binary mode. Patch by Ryosuke Ito.

bpo-25503 [https://bugs.python.org/issue?@action=redirect&bpo=25503]: Fixed inspect.getdoc() for inherited docstrings of properties. Original patch by John Mark Vandenberg.

bpo-25515 [https://bugs.python.org/issue?@action=redirect&bpo=25515]: Always use os.urandom as a source of randomness in uuid.uuid4.

bpo-21827 [https://bugs.python.org/issue?@action=redirect&bpo=21827]: Fixed textwrap.dedent() for the case when largest common whitespace is a substring of smallest leading whitespace. Based on patch by Robert Li.

bpo-25447 [https://bugs.python.org/issue?@action=redirect&bpo=25447]: The lru_cache() wrapper objects now can be copied and pickled (by returning the original object unchanged).

bpo-25390 [https://bugs.python.org/issue?@action=redirect&bpo=25390]: typing: Don’t crash on Union[str, Pattern].

bpo-25441 [https://bugs.python.org/issue?@action=redirect&bpo=25441]: asyncio: Raise error from drain() when socket is closed.

bpo-25410 [https://bugs.python.org/issue?@action=redirect&bpo=25410]: Cleaned up and fixed minor bugs in C implementation of OrderedDict.

bpo-25411 [https://bugs.python.org/issue?@action=redirect&bpo=25411]: Improved Unicode support in SMTPHandler through better use of the email package. Thanks to user simon04 for the patch.

bpo-25407 [https://bugs.python.org/issue?@action=redirect&bpo=25407]: Remove mentions of the formatter module being removed in Python 3.6.

bpo-25406 [https://bugs.python.org/issue?@action=redirect&bpo=25406]: Fixed a bug in C implementation of OrderedDict.move_to_end() that caused segmentation fault or hang in iterating after moving several items to the start of ordered dict.

bpo-25364 [https://bugs.python.org/issue?@action=redirect&bpo=25364]: zipfile now works in threads disabled builds.

bpo-25328 [https://bugs.python.org/issue?@action=redirect&bpo=25328]: smtpd’s SMTPChannel now correctly raises a ValueError if both decode_data and enable_SMTPUTF8 are set to true.

bpo-25316 [https://bugs.python.org/issue?@action=redirect&bpo=25316]: distutils raises OSError instead of DistutilsPlatformError when MSVC is not installed.

bpo-25380 [https://bugs.python.org/issue?@action=redirect&bpo=25380]: Fixed protocol for the STACK_GLOBAL opcode in pickletools.opcodes.

bpo-23972 [https://bugs.python.org/issue?@action=redirect&bpo=23972]: Updates asyncio datagram create method allowing reuseport and reuseaddr socket options to be set prior to binding the socket. Mirroring the existing asyncio create_server method the reuseaddr option for datagram sockets defaults to True if the O/S is ‘posix’ (except if the platform is Cygwin). Patch by Chris Laws.

bpo-25304 [https://bugs.python.org/issue?@action=redirect&bpo=25304]: Add asyncio.run_coroutine_threadsafe(). This lets you submit a coroutine to a loop from another thread, returning a concurrent.futures.Future. By Vincent Michel.

bpo-25232 [https://bugs.python.org/issue?@action=redirect&bpo=25232]: Fix CGIRequestHandler to split the query from the URL at the first question mark (?) rather than the last. Patch from Xiang Zhang.

bpo-24657 [https://bugs.python.org/issue?@action=redirect&bpo=24657]: Prevent CGIRequestHandler from collapsing slashes in the query part of the URL as if it were a path. Patch from Xiang Zhang.

bpo-24483 [https://bugs.python.org/issue?@action=redirect&bpo=24483]: C implementation of functools.lru_cache() now calculates key’s hash only once.

bpo-22958 [https://bugs.python.org/issue?@action=redirect&bpo=22958]: Constructor and update method of weakref.WeakValueDictionary now accept the self and the dict keyword arguments.

bpo-22609 [https://bugs.python.org/issue?@action=redirect&bpo=22609]: Constructor of collections.UserDict now accepts the self keyword argument.

bpo-25111 [https://bugs.python.org/issue?@action=redirect&bpo=25111]: Fixed comparison of traceback.FrameSummary.

bpo-25262 [https://bugs.python.org/issue?@action=redirect&bpo=25262]: Added support for BINBYTES8 opcode in Python implementation of unpickler. Highest 32 bits of 64-bit size for BINUNICODE8 and BINBYTES8 opcodes no longer silently ignored on 32-bit platforms in C implementation.

bpo-25034 [https://bugs.python.org/issue?@action=redirect&bpo=25034]: Fix string.Formatter problem with auto-numbering and nested format_specs. Patch by Anthon van der Neut.

bpo-25233 [https://bugs.python.org/issue?@action=redirect&bpo=25233]: Rewrite the guts of asyncio.Queue and asyncio.Semaphore to be more understandable and correct.

bpo-25203 [https://bugs.python.org/issue?@action=redirect&bpo=25203]: Failed readline.set_completer_delims() no longer left the module in inconsistent state.

bpo-23600 [https://bugs.python.org/issue?@action=redirect&bpo=23600]: Default implementation of tzinfo.fromutc() was returning wrong results in some cases.

bpo-23329 [https://bugs.python.org/issue?@action=redirect&bpo=23329]: Allow the ssl module to be built with older versions of LibreSSL.

Prevent overflow in _Unpickler_Read.

bpo-25047 [https://bugs.python.org/issue?@action=redirect&bpo=25047]: The XML encoding declaration written by Element Tree now respects the letter case given by the user. This restores the ability to write encoding names in uppercase like “UTF-8”, which worked in Python 2.

bpo-25135 [https://bugs.python.org/issue?@action=redirect&bpo=25135]: Make deque_clear() safer by emptying the deque before clearing. This helps avoid possible reentrancy issues.

bpo-19143 [https://bugs.python.org/issue?@action=redirect&bpo=19143]: platform module now reads Windows version from kernel32.dll to avoid compatibility shims.

bpo-25092 [https://bugs.python.org/issue?@action=redirect&bpo=25092]: Fix datetime.strftime() failure when errno was already set to EINVAL.

bpo-23517 [https://bugs.python.org/issue?@action=redirect&bpo=23517]: Fix rounding in fromtimestamp() and utcfromtimestamp() methods of datetime.datetime: microseconds are now rounded to nearest with ties going to nearest even integer (ROUND_HALF_EVEN), instead of being rounding towards minus infinity (ROUND_FLOOR). It’s important that these methods use the same rounding mode than datetime.timedelta to keep the property: (datetime(1970,1,1) + timedelta(seconds=t)) == datetime.utcfromtimestamp(t). It also the rounding mode used by round(float) for example.

bpo-25155 [https://bugs.python.org/issue?@action=redirect&bpo=25155]: Fix datetime.datetime.now() and datetime.datetime.utcnow() on Windows to support date after year 2038. It was a regression introduced in Python 3.5.0.

bpo-25108 [https://bugs.python.org/issue?@action=redirect&bpo=25108]: Omitted internal frames in traceback functions print_stack(), format_stack(), and extract_stack() called without arguments.

bpo-25118 [https://bugs.python.org/issue?@action=redirect&bpo=25118]: Fix a regression of Python 3.5.0 in os.waitpid() on Windows.

bpo-24684 [https://bugs.python.org/issue?@action=redirect&bpo=24684]: socket.socket.getaddrinfo() now calls PyUnicode_AsEncodedString() instead of calling the encode() method of the host, to handle correctly custom string with an encode() method which doesn’t return a byte string. The encoder of the IDNA codec is now called directly instead of calling the encode() method of the string.

bpo-25060 [https://bugs.python.org/issue?@action=redirect&bpo=25060]: Correctly compute stack usage of the BUILD_MAP opcode.

bpo-24857 [https://bugs.python.org/issue?@action=redirect&bpo=24857]: Comparing call_args to a long sequence now correctly returns a boolean result instead of raising an exception. Patch by A Kaptur.

bpo-23144 [https://bugs.python.org/issue?@action=redirect&bpo=23144]: Make sure that HTMLParser.feed() returns all the data, even when convert_charrefs is True.

bpo-24982 [https://bugs.python.org/issue?@action=redirect&bpo=24982]: shutil.make_archive() with the “zip” format now adds entries for directories (including empty directories) in ZIP file.

bpo-25019 [https://bugs.python.org/issue?@action=redirect&bpo=25019]: Fixed a crash caused by setting non-string key of expat parser. Based on patch by John Leitch.

bpo-16180 [https://bugs.python.org/issue?@action=redirect&bpo=16180]: Exit pdb if file has syntax error, instead of trapping user in an infinite loop. Patch by Xavier de Gaye.

bpo-24891 [https://bugs.python.org/issue?@action=redirect&bpo=24891]: Fix a race condition at Python startup if the file descriptor of stdin (0), stdout (1) or stderr (2) is closed while Python is creating sys.stdin, sys.stdout and sys.stderr objects. These attributes are now set to None if the creation of the object failed, instead of raising an OSError exception. Initial patch written by Marco Paolini.

bpo-24992 [https://bugs.python.org/issue?@action=redirect&bpo=24992]: Fix error handling and a race condition (related to garbage collection) in collections.OrderedDict constructor.

bpo-24881 [https://bugs.python.org/issue?@action=redirect&bpo=24881]: Fixed setting binary mode in Python implementation of FileIO on Windows and Cygwin. Patch from Akira Li.

bpo-25578 [https://bugs.python.org/issue?@action=redirect&bpo=25578]: Fix (another) memory leak in SSLSocket.getpeercer().

bpo-25530 [https://bugs.python.org/issue?@action=redirect&bpo=25530]: Disable the vulnerable SSLv3 protocol by default when creating ssl.SSLContext.

bpo-25569 [https://bugs.python.org/issue?@action=redirect&bpo=25569]: Fix memory leak in SSLSocket.getpeercert().

bpo-25471 [https://bugs.python.org/issue?@action=redirect&bpo=25471]: Sockets returned from accept() shouldn’t appear to be nonblocking.

bpo-25319 [https://bugs.python.org/issue?@action=redirect&bpo=25319]: When threading.Event is reinitialized, the underlying condition should use a regular lock rather than a recursive lock.

bpo-21112 [https://bugs.python.org/issue?@action=redirect&bpo=21112]: Fix regression in unittest.expectedFailure on subclasses. Patch from Berker Peksag.

bpo-24764 [https://bugs.python.org/issue?@action=redirect&bpo=24764]: cgi.FieldStorage.read_multi() now ignores the Content-Length header in part headers. Patch written by Peter Landry and reviewed by Pierre Quentel.

bpo-24913 [https://bugs.python.org/issue?@action=redirect&bpo=24913]: Fix overrun error in deque.index(). Found by John Leitch and Bryce Darling.

bpo-24774 [https://bugs.python.org/issue?@action=redirect&bpo=24774]: Fix docstring in http.server.test. Patch from Chiu-Hsiang Hsu.

bpo-21159 [https://bugs.python.org/issue?@action=redirect&bpo=21159]: Improve message in configparser.InterpolationMissingOptionError. Patch from Łukasz Langa.

bpo-20362 [https://bugs.python.org/issue?@action=redirect&bpo=20362]: Honour TestCase.longMessage correctly in assertRegex. Patch from Ilia Kurenkov.

bpo-23572 [https://bugs.python.org/issue?@action=redirect&bpo=23572]: Fixed functools.singledispatch on classes with false metaclasses. Patch by Ethan Furman.

asyncio: ensure_future() now accepts awaitable objects.

IDLE

bpo-15348 [https://bugs.python.org/issue?@action=redirect&bpo=15348]: Stop the debugger engine (normally in a user process) before closing the debugger window (running in the IDLE process). This prevents the RuntimeErrors that were being caught and ignored.

bpo-24455 [https://bugs.python.org/issue?@action=redirect&bpo=24455]: Prevent IDLE from hanging when a) closing the shell while the debugger is active (15347); b) closing the debugger with the [X] button (15348); and c) activating the debugger when already active (24455). The patch by Mark Roseman does this by making two changes. 1. Suspend and resume the gui.interaction method with the tcl vwait mechanism intended for this purpose (instead of root.mainloop & .quit). 2. In gui.run, allow any existing interaction to terminate first.

Change ‘The program’ to ‘Your program’ in an IDLE ‘kill program?’ message to make it clearer that the program referred to is the currently running user program, not IDLE itself.

bpo-24750 [https://bugs.python.org/issue?@action=redirect&bpo=24750]: Improve the appearance of the IDLE editor window status bar. Patch by Mark Roseman.

bpo-25313 [https://bugs.python.org/issue?@action=redirect&bpo=25313]: Change the handling of new built-in text color themes to better address the compatibility problem introduced by the addition of IDLE Dark. Consistently use the revised idleConf.CurrentTheme everywhere in idlelib.

bpo-24782 [https://bugs.python.org/issue?@action=redirect&bpo=24782]: Extension configuration is now a tab in the IDLE Preferences dialog rather than a separate dialog. The former tabs are now a sorted list. Patch by Mark Roseman.

bpo-22726 [https://bugs.python.org/issue?@action=redirect&bpo=22726]: Re-activate the config dialog help button with some content about the other buttons and the new IDLE Dark theme.

bpo-24820 [https://bugs.python.org/issue?@action=redirect&bpo=24820]: IDLE now has an ‘IDLE Dark’ built-in text color theme. It is more or less IDLE Classic inverted, with a cobalt blue background. Strings, comments, keywords, … are still green, red, orange, … . To use it with IDLEs released before November 2015, hit the ‘Save as New Custom Theme’ button and enter a new name, such as ‘Custom Dark’. The custom theme will work with any IDLE release, and can be modified.

bpo-25224 [https://bugs.python.org/issue?@action=redirect&bpo=25224]: README.txt is now an idlelib index for IDLE developers and curious users. The previous user content is now in the IDLE doc chapter. ‘IDLE’ now means ‘Integrated Development and Learning Environment’.

bpo-24820 [https://bugs.python.org/issue?@action=redirect&bpo=24820]: Users can now set breakpoint colors in Settings -> Custom Highlighting. Original patch by Mark Roseman.

bpo-24972 [https://bugs.python.org/issue?@action=redirect&bpo=24972]: Inactive selection background now matches active selection background, as configured by users, on all systems. Found items are now always highlighted on Windows. Initial patch by Mark Roseman.

bpo-24570 [https://bugs.python.org/issue?@action=redirect&bpo=24570]: Idle: make calltip and completion boxes appear on Macs affected by a tk regression. Initial patch by Mark Roseman.

bpo-24988 [https://bugs.python.org/issue?@action=redirect&bpo=24988]: Idle ScrolledList context menus (used in debugger) now work on Mac Aqua. Patch by Mark Roseman.

bpo-24801 [https://bugs.python.org/issue?@action=redirect&bpo=24801]: Make right-click for context menu work on Mac Aqua. Patch by Mark Roseman.

bpo-25173 [https://bugs.python.org/issue?@action=redirect&bpo=25173]: Associate tkinter messageboxes with a specific widget. For Mac OSX, make them a ‘sheet’. Patch by Mark Roseman.

bpo-25198 [https://bugs.python.org/issue?@action=redirect&bpo=25198]: Enhance the initial html viewer now used for Idle Help. Properly indent fixed-pitch text (patch by Mark Roseman). Give code snippet a very Sphinx-like light blueish-gray background. Re-use initial width and height set by users for shell and editor. When the Table of Contents (TOC) menu is used, put the section header at the top of the screen.

bpo-25225 [https://bugs.python.org/issue?@action=redirect&bpo=25225]: Condense and rewrite Idle doc section on text colors.

bpo-21995 [https://bugs.python.org/issue?@action=redirect&bpo=21995]: Explain some differences between IDLE and console Python.

bpo-22820 [https://bugs.python.org/issue?@action=redirect&bpo=22820]: Explain need for print when running file from Idle editor.

bpo-25224 [https://bugs.python.org/issue?@action=redirect&bpo=25224]: Doc: augment Idle feature list and no-subprocess section.

bpo-25219 [https://bugs.python.org/issue?@action=redirect&bpo=25219]: Update doc for Idle command line options. Some were missing and notes were not correct.

bpo-24861 [https://bugs.python.org/issue?@action=redirect&bpo=24861]: Most of idlelib is private and subject to change. Use idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

bpo-25199 [https://bugs.python.org/issue?@action=redirect&bpo=25199]: Idle: add synchronization comments for future maintainers.

bpo-16893 [https://bugs.python.org/issue?@action=redirect&bpo=16893]: Replace help.txt with help.html for Idle doc display. The new idlelib/help.html is rstripped Doc/build/html/library/idle.html. It looks better than help.txt and will better document Idle as released. The tkinter html viewer that works for this file was written by Mark Roseman. The now unused EditorWindow.HelpDialog class and helt.txt file are deprecated.

bpo-24199 [https://bugs.python.org/issue?@action=redirect&bpo=24199]: Deprecate unused idlelib.idlever with possible removal in 3.6.

bpo-24790 [https://bugs.python.org/issue?@action=redirect&bpo=24790]: Remove extraneous code (which also create 2 & 3 conflicts).

Documentation

bpo-22558 [https://bugs.python.org/issue?@action=redirect&bpo=22558]: Add remaining doc links to source code for Python-coded modules. Patch by Yoni Lavi.

bpo-12067 [https://bugs.python.org/issue?@action=redirect&bpo=12067]: Rewrite Comparisons section in the Expressions chapter of the language reference. Some of the details of comparing mixed types were incorrect or ambiguous. NotImplemented is only relevant at a lower level than the Expressions chapter. Added details of comparing range() objects, and default behaviour and consistency suggestions for user-defined classes. Patch from Andy Maier.

bpo-24952 [https://bugs.python.org/issue?@action=redirect&bpo=24952]: Clarify the default size argument of stack_size() in the “threading” and “_thread” modules. Patch from Mattip.

bpo-23725 [https://bugs.python.org/issue?@action=redirect&bpo=23725]: Overhaul tempfile docs. Note deprecated status of mktemp. Patch from Zbigniew Jędrzejewski-Szmek.

bpo-24808 [https://bugs.python.org/issue?@action=redirect&bpo=24808]: Update the types of some PyTypeObject fields. Patch by Joseph Weston.

bpo-22812 [https://bugs.python.org/issue?@action=redirect&bpo=22812]: Fix unittest discovery examples. Patch from Pam McA’Nulty.

Tests

bpo-25449 [https://bugs.python.org/issue?@action=redirect&bpo=25449]: Added tests for OrderedDict subclasses.

bpo-25099 [https://bugs.python.org/issue?@action=redirect&bpo=25099]: Make test_compileall not fail when an entry on sys.path cannot be written to (commonly seen in administrative installs on Windows).

bpo-23919 [https://bugs.python.org/issue?@action=redirect&bpo=23919]: Prevents assert dialogs appearing in the test suite.

PCbuild\rt.bat now accepts an unlimited number of arguments to pass along to regrtest.py. Previously there was a limit of 9.

Build

bpo-24915 [https://bugs.python.org/issue?@action=redirect&bpo=24915]: Add LLVM support for PGO builds and use the test suite to generate the profile data. Initial patch by Alecsandru Patrascu of Intel.

bpo-24910 [https://bugs.python.org/issue?@action=redirect&bpo=24910]: Windows MSIs now have unique display names.

bpo-24986 [https://bugs.python.org/issue?@action=redirect&bpo=24986]: It is now possible to build Python on Windows without errors when external libraries are not available.

Windows

bpo-25450 [https://bugs.python.org/issue?@action=redirect&bpo=25450]: Updates shortcuts to start Python in installation directory.

bpo-25164 [https://bugs.python.org/issue?@action=redirect&bpo=25164]: Changes default all-users install directory to match per-user directory.

bpo-25143 [https://bugs.python.org/issue?@action=redirect&bpo=25143]: Improves installer error messages for unsupported platforms.

bpo-25163 [https://bugs.python.org/issue?@action=redirect&bpo=25163]: Display correct directory in installer when using non-default settings.

bpo-25361 [https://bugs.python.org/issue?@action=redirect&bpo=25361]: Disables use of SSE2 instructions in Windows 32-bit build

bpo-25089 [https://bugs.python.org/issue?@action=redirect&bpo=25089]: Adds logging to installer for case where launcher is not selected on upgrade.

bpo-25165 [https://bugs.python.org/issue?@action=redirect&bpo=25165]: Windows uninstallation should not remove launcher if other versions remain

bpo-25112 [https://bugs.python.org/issue?@action=redirect&bpo=25112]: py.exe launcher is missing icons

bpo-25102 [https://bugs.python.org/issue?@action=redirect&bpo=25102]: Windows installer does not precompile for -O or -OO.

bpo-25081 [https://bugs.python.org/issue?@action=redirect&bpo=25081]: Makes Back button in installer go back to upgrade page when upgrading.

bpo-25091 [https://bugs.python.org/issue?@action=redirect&bpo=25091]: Increases font size of the installer.

bpo-25126 [https://bugs.python.org/issue?@action=redirect&bpo=25126]: Clarifies that the non-web installer will download some components.

bpo-25213 [https://bugs.python.org/issue?@action=redirect&bpo=25213]: Restores requestedExecutionLevel to manifest to disable UAC virtualization.

bpo-25022 [https://bugs.python.org/issue?@action=redirect&bpo=25022]: Removed very outdated PC/example_nt/ directory.

Tools/Demos

bpo-25440 [https://bugs.python.org/issue?@action=redirect&bpo=25440]: Fix output of python-config –extension-suffix.

Python 3.5.0 final

Release date: 2015-09-13

Build

bpo-25071 [https://bugs.python.org/issue?@action=redirect&bpo=25071]: Windows installer should not require TargetDir parameter when installing quietly.

Python 3.5.0 release candidate 4

Release date: 2015-09-09

Library

bpo-25029 [https://bugs.python.org/issue?@action=redirect&bpo=25029]: Fixes MemoryError in test_strptime.

Build

bpo-25027 [https://bugs.python.org/issue?@action=redirect&bpo=25027]: Reverts partial-static build options and adds vcruntime140.dll to Windows installation.

Python 3.5.0 release candidate 3

Release date: 2015-09-07

Core and Builtins

bpo-24305 [https://bugs.python.org/issue?@action=redirect&bpo=24305]: Prevent import subsystem stack frames from being counted by the warnings.warn(stacklevel=) parameter.

bpo-24912 [https://bugs.python.org/issue?@action=redirect&bpo=24912]: Prevent __class__ assignment to immutable built-in objects.

bpo-24975 [https://bugs.python.org/issue?@action=redirect&bpo=24975]: Fix AST compilation for PEP 448 [https://peps.python.org/pep-0448/] syntax.

Library

bpo-24917 [https://bugs.python.org/issue?@action=redirect&bpo=24917]: time_strftime() buffer over-read.

bpo-24748 [https://bugs.python.org/issue?@action=redirect&bpo=24748]: To resolve a compatibility problem found with py2exe and pywin32, imp.load_dynamic() once again ignores previously loaded modules to support Python modules replacing themselves with extension modules. Patch by Petr Viktorin.

bpo-24635 [https://bugs.python.org/issue?@action=redirect&bpo=24635]: Fixed a bug in typing.py where isinstance([], typing.Iterable) would return True once, then False on subsequent calls.

bpo-24989 [https://bugs.python.org/issue?@action=redirect&bpo=24989]: Fixed buffer overread in BytesIO.readline() if a position is set beyond size. Based on patch by John Leitch.

bpo-24913 [https://bugs.python.org/issue?@action=redirect&bpo=24913]: Fix overrun error in deque.index(). Found by John Leitch and Bryce Darling.

Python 3.5.0 release candidate 2

Release date: 2015-08-25

Core and Builtins

bpo-24769 [https://bugs.python.org/issue?@action=redirect&bpo=24769]: Interpreter now starts properly when dynamic loading is disabled. Patch by Petr Viktorin.

bpo-21167 [https://bugs.python.org/issue?@action=redirect&bpo=21167]: NAN operations are now handled correctly when python is compiled with ICC even if -fp-model strict is not specified.

bpo-24492 [https://bugs.python.org/issue?@action=redirect&bpo=24492]: A “package” lacking a __name__ attribute when trying to perform a from .. import ... statement will trigger an ImportError instead of an AttributeError.

Library

bpo-24847 [https://bugs.python.org/issue?@action=redirect&bpo=24847]: Removes vcruntime140.dll dependency from Tcl/Tk.

bpo-24839 [https://bugs.python.org/issue?@action=redirect&bpo=24839]: platform._syscmd_ver raises DeprecationWarning

bpo-24867 [https://bugs.python.org/issue?@action=redirect&bpo=24867]: Fix Task.get_stack() for ‘async def’ coroutines

Python 3.5.0 release candidate 1

Release date: 2015-08-09

Core and Builtins

bpo-24667 [https://bugs.python.org/issue?@action=redirect&bpo=24667]: Resize odict in all cases that the underlying dict resizes.

Library

bpo-24824 [https://bugs.python.org/issue?@action=redirect&bpo=24824]: Signatures of codecs.encode() and codecs.decode() now are compatible with pydoc.

bpo-24634 [https://bugs.python.org/issue?@action=redirect&bpo=24634]: Importing uuid should not try to load libc on Windows

bpo-24798 [https://bugs.python.org/issue?@action=redirect&bpo=24798]: _msvccompiler.py doesn’t properly support manifests

bpo-4395 [https://bugs.python.org/issue?@action=redirect&bpo=4395]: Better testing and documentation of binary operators. Patch by Martin Panter.

bpo-23973 [https://bugs.python.org/issue?@action=redirect&bpo=23973]: Update typing.py from GitHub repo.

bpo-23004 [https://bugs.python.org/issue?@action=redirect&bpo=23004]: mock_open() now reads binary data correctly when the type of read_data is bytes. Initial patch by Aaron Hill.

bpo-23888 [https://bugs.python.org/issue?@action=redirect&bpo=23888]: Handle fractional time in cookie expiry. Patch by ssh.

bpo-23652 [https://bugs.python.org/issue?@action=redirect&bpo=23652]: Make it possible to compile the select module against the libc headers from the Linux Standard Base, which do not include some EPOLL macros. Patch by Matt Frank.

bpo-22932 [https://bugs.python.org/issue?@action=redirect&bpo=22932]: Fix timezones in email.utils.formatdate. Patch from Dmitry Shachnev.

bpo-23779 [https://bugs.python.org/issue?@action=redirect&bpo=23779]: imaplib raises TypeError if authenticator tries to abort. Patch from Craig Holmquist.

bpo-23319 [https://bugs.python.org/issue?@action=redirect&bpo=23319]: Fix ctypes.BigEndianStructure, swap correctly bytes. Patch written by Matthieu Gautier.

bpo-23254 [https://bugs.python.org/issue?@action=redirect&bpo=23254]: Document how to close the TCPServer listening socket. Patch from Martin Panter.

bpo-19450 [https://bugs.python.org/issue?@action=redirect&bpo=19450]: Update Windows and OS X installer builds to use SQLite 3.8.11.

bpo-17527 [https://bugs.python.org/issue?@action=redirect&bpo=17527]: Add PATCH to wsgiref.validator. Patch from Luca Sbardella.

bpo-24791 [https://bugs.python.org/issue?@action=redirect&bpo=24791]: Fix grammar regression for call syntax: ‘g(*a or b)’.

IDLE

bpo-23672 [https://bugs.python.org/issue?@action=redirect&bpo=23672]: Allow Idle to edit and run files with astral chars in name. Patch by Mohd Sanad Zaki Rizvi.

bpo-24745 [https://bugs.python.org/issue?@action=redirect&bpo=24745]: Idle editor default font. Switch from Courier to platform-sensitive TkFixedFont. This should not affect current customized font selections. If there is a problem, edit $HOME/.idlerc/config-main.cfg and remove ‘fontxxx’ entries from [Editor Window]. Patch by Mark Roseman.

bpo-21192 [https://bugs.python.org/issue?@action=redirect&bpo=21192]: Idle editor. When a file is run, put its name in the restart bar. Do not print false prompts. Original patch by Adnan Umer.

bpo-13884 [https://bugs.python.org/issue?@action=redirect&bpo=13884]: Idle menus. Remove tearoff lines. Patch by Roger Serwy.

Documentation

bpo-24129 [https://bugs.python.org/issue?@action=redirect&bpo=24129]: Clarify the reference documentation for name resolution. This includes removing the assumption that readers will be familiar with the name resolution scheme Python used prior to the introduction of lexical scoping for function namespaces. Patch by Ivan Levkivskyi.

bpo-20769 [https://bugs.python.org/issue?@action=redirect&bpo=20769]: Improve reload() docs. Patch by Dorian Pula.

bpo-23589 [https://bugs.python.org/issue?@action=redirect&bpo=23589]: Remove duplicate sentence from the FAQ. Patch by Yongzhi Pan.

bpo-24729 [https://bugs.python.org/issue?@action=redirect&bpo=24729]: Correct IO tutorial to match implementation regarding encoding parameter to open function.

Tests

bpo-24751 [https://bugs.python.org/issue?@action=redirect&bpo=24751]: When running regrtest with the -w command line option, a test run is no longer marked as a failure if all tests succeed when re-run.

Python 3.5.0 beta 4

Release date: 2015-07-26

Core and Builtins

bpo-23573 [https://bugs.python.org/issue?@action=redirect&bpo=23573]: Restored optimization of bytes.rfind() and bytearray.rfind() for single-byte argument on Linux.

bpo-24569 [https://bugs.python.org/issue?@action=redirect&bpo=24569]: Make PEP 448 [https://peps.python.org/pep-0448/] dictionary evaluation more consistent.

bpo-24583 [https://bugs.python.org/issue?@action=redirect&bpo=24583]: Fix crash when set is mutated while being updated.

bpo-24407 [https://bugs.python.org/issue?@action=redirect&bpo=24407]: Fix crash when dict is mutated while being updated.

bpo-24619 [https://bugs.python.org/issue?@action=redirect&bpo=24619]: New approach for tokenizing async/await. As a consequence, it is now possible to have one-line ‘async def foo(): await ..’ functions.

bpo-24687 [https://bugs.python.org/issue?@action=redirect&bpo=24687]: Plug refleak on SyntaxError in function parameters annotations.

bpo-15944 [https://bugs.python.org/issue?@action=redirect&bpo=15944]: memoryview: Allow arbitrary formats when casting to bytes. Patch by Martin Panter.

Library

bpo-23441 [https://bugs.python.org/issue?@action=redirect&bpo=23441]: rcompleter now prints a tab character instead of displaying possible completions for an empty word. Initial patch by Martin Sekera.

bpo-24683 [https://bugs.python.org/issue?@action=redirect&bpo=24683]: Fixed crashes in _json functions called with arguments of inappropriate type.

bpo-21697 [https://bugs.python.org/issue?@action=redirect&bpo=21697]: shutil.copytree() now correctly handles symbolic links that point to directories. Patch by Eduardo Seabra and Thomas Kluyver.

bpo-14373 [https://bugs.python.org/issue?@action=redirect&bpo=14373]: Fixed segmentation fault when gc.collect() is called during constructing lru_cache (C implementation).

bpo-24695 [https://bugs.python.org/issue?@action=redirect&bpo=24695]: Fix a regression in traceback.print_exception(). If exc_traceback is None we shouldn’t print a traceback header like described in the documentation.

bpo-24620 [https://bugs.python.org/issue?@action=redirect&bpo=24620]: Random.setstate() now validates the value of state last element.

bpo-22485 [https://bugs.python.org/issue?@action=redirect&bpo=22485]: Fixed an issue that caused inspect.getsource to return incorrect results on nested functions.

bpo-22153 [https://bugs.python.org/issue?@action=redirect&bpo=22153]: Improve unittest docs. Patch from Martin Panter and evilzero.

bpo-24580 [https://bugs.python.org/issue?@action=redirect&bpo=24580]: Symbolic group references to open group in re patterns now are explicitly forbidden as well as numeric group references.

bpo-24206 [https://bugs.python.org/issue?@action=redirect&bpo=24206]: Fixed __eq__ and __ne__ methods of inspect classes.

bpo-24631 [https://bugs.python.org/issue?@action=redirect&bpo=24631]: Fixed regression in the timeit module with multiline setup.

bpo-18622 [https://bugs.python.org/issue?@action=redirect&bpo=18622]: unittest.mock.mock_open().reset_mock would recurse infinitely. Patch from Nicola Palumbo and Laurent De Buyst.

bpo-23661 [https://bugs.python.org/issue?@action=redirect&bpo=23661]: unittest.mock side_effects can now be exceptions again. This was a regression vs Python 3.4. Patch from Ignacio Rossi

bpo-24608 [https://bugs.python.org/issue?@action=redirect&bpo=24608]: chunk.Chunk.read() now always returns bytes, not str.

bpo-18684 [https://bugs.python.org/issue?@action=redirect&bpo=18684]: Fixed reading out of the buffer in the re module.

bpo-24259 [https://bugs.python.org/issue?@action=redirect&bpo=24259]: tarfile now raises a ReadError if an archive is truncated inside a data segment.

bpo-15014 [https://bugs.python.org/issue?@action=redirect&bpo=15014]: SMTP.auth() and SMTP.login() now support RFC 4954’s optional initial-response argument to the SMTP AUTH command.

bpo-24669 [https://bugs.python.org/issue?@action=redirect&bpo=24669]: Fix inspect.getsource() for ‘async def’ functions. Patch by Kai Groner.

bpo-24688 [https://bugs.python.org/issue?@action=redirect&bpo=24688]: ast.get_docstring() for ‘async def’ functions.

Build

bpo-24603 [https://bugs.python.org/issue?@action=redirect&bpo=24603]: Update Windows builds and OS X 10.5 installer to use OpenSSL 1.0.2d.

Python 3.5.0 beta 3

Release date: 2015-07-05

Core and Builtins

bpo-24467 [https://bugs.python.org/issue?@action=redirect&bpo=24467]: Fixed possible buffer over-read in bytearray. The bytearray object now always allocates place for trailing null byte and it’s buffer now is always null-terminated.

Upgrade to Unicode 8.0.0.

bpo-24345 [https://bugs.python.org/issue?@action=redirect&bpo=24345]: Add Py_tp_finalize slot for the stable ABI.

bpo-24400 [https://bugs.python.org/issue?@action=redirect&bpo=24400]: Introduce a distinct type for PEP 492 [https://peps.python.org/pep-0492/] coroutines; add types.CoroutineType, inspect.getcoroutinestate, inspect.getcoroutinelocals; coroutines no longer use CO_GENERATOR flag; sys.set_coroutine_wrapper works only for ‘async def’ coroutines; inspect.iscoroutine no longer uses collections.abc.Coroutine, it’s intended to test for pure ‘async def’ coroutines only; add new opcode: GET_YIELD_FROM_ITER; fix generators wrapper used in types.coroutine to be instance of collections.abc.Generator; collections.abc.Awaitable and collections.abc.Coroutine can no longer be used to detect generator-based coroutines–use inspect.isawaitable instead.

bpo-24450 [https://bugs.python.org/issue?@action=redirect&bpo=24450]: Add gi_yieldfrom to generators and cr_await to coroutines. Contributed by Benno Leslie and Yury Selivanov.

bpo-19235 [https://bugs.python.org/issue?@action=redirect&bpo=19235]: Add new RecursionError exception. Patch by Georg Brandl.

Library

bpo-21750 [https://bugs.python.org/issue?@action=redirect&bpo=21750]: mock_open.read_data can now be read from each instance, as it could in Python 3.3.

bpo-24552 [https://bugs.python.org/issue?@action=redirect&bpo=24552]: Fix use after free in an error case of the _pickle module.

bpo-24514 [https://bugs.python.org/issue?@action=redirect&bpo=24514]: tarfile now tolerates number fields consisting of only whitespace.

bpo-19176 [https://bugs.python.org/issue?@action=redirect&bpo=19176]: Fixed doctype() related bugs in C implementation of ElementTree. A deprecation warning no longer issued by XMLParser subclass with default doctype() method. Direct call of doctype() now issues a warning. Parser’s doctype() now is not called if target’s doctype() is called. Based on patch by Martin Panter.

bpo-20387 [https://bugs.python.org/issue?@action=redirect&bpo=20387]: Restore semantic round-trip correctness in tokenize/untokenize for tab-indented blocks.

bpo-24456 [https://bugs.python.org/issue?@action=redirect&bpo=24456]: Fixed possible buffer over-read in adpcm2lin() and lin2adpcm() functions of the audioop module.

bpo-24336 [https://bugs.python.org/issue?@action=redirect&bpo=24336]: The contextmanager decorator now works with functions with keyword arguments called “func” and “self”. Patch by Martin Panter.

bpo-24522 [https://bugs.python.org/issue?@action=redirect&bpo=24522]: Fix possible integer overflow in json accelerator module.

bpo-24489 [https://bugs.python.org/issue?@action=redirect&bpo=24489]: ensure a previously set C errno doesn’t disturb cmath.polar().

bpo-24408 [https://bugs.python.org/issue?@action=redirect&bpo=24408]: Fixed AttributeError in measure() and metrics() methods of tkinter.Font.

bpo-14373 [https://bugs.python.org/issue?@action=redirect&bpo=14373]: C implementation of functools.lru_cache() now can be used with methods.

bpo-24347 [https://bugs.python.org/issue?@action=redirect&bpo=24347]: Set KeyError if PyDict_GetItemWithError returns NULL.

bpo-24348 [https://bugs.python.org/issue?@action=redirect&bpo=24348]: Drop superfluous incref/decref.

bpo-24359 [https://bugs.python.org/issue?@action=redirect&bpo=24359]: Check for changed OrderedDict size during iteration.

bpo-24368 [https://bugs.python.org/issue?@action=redirect&bpo=24368]: Support keyword arguments in OrderedDict methods.

bpo-24362 [https://bugs.python.org/issue?@action=redirect&bpo=24362]: Simplify the C OrderedDict fast nodes resize logic.

bpo-24377 [https://bugs.python.org/issue?@action=redirect&bpo=24377]: Fix a ref leak in OrderedDict.__repr__.

bpo-24369 [https://bugs.python.org/issue?@action=redirect&bpo=24369]: Defend against key-changes during iteration.

Tests

bpo-24373 [https://bugs.python.org/issue?@action=redirect&bpo=24373]: _testmultiphase and xxlimited now use tp_traverse and tp_finalize to avoid reference leaks encountered when combining tp_dealloc with PyType_FromSpec (see bpo-16690 [https://bugs.python.org/issue?@action=redirect&bpo=16690] for details)

Documentation

bpo-24458 [https://bugs.python.org/issue?@action=redirect&bpo=24458]: Update documentation to cover multi-phase initialization for extension modules (PEP 489). Patch by Petr Viktorin.

bpo-24351 [https://bugs.python.org/issue?@action=redirect&bpo=24351]: Clarify what is meant by “identifier” in the context of string.Template instances.

Build

bpo-24432 [https://bugs.python.org/issue?@action=redirect&bpo=24432]: Update Windows builds and OS X 10.5 installer to use OpenSSL 1.0.2c.

Python 3.5.0 beta 2

Release date: 2015-05-31

Core and Builtins

bpo-24284 [https://bugs.python.org/issue?@action=redirect&bpo=24284]: The startswith and endswith methods of the str class no longer return True when finding the empty string and the indexes are completely out of range.

bpo-24115 [https://bugs.python.org/issue?@action=redirect&bpo=24115]: Update uses of PyObject_IsTrue(), PyObject_Not(), PyObject_IsInstance(), PyObject_RichCompareBool() and _PyDict_Contains() to check for and handle errors correctly.

bpo-24328 [https://bugs.python.org/issue?@action=redirect&bpo=24328]: Fix importing one character extension modules.

bpo-11205 [https://bugs.python.org/issue?@action=redirect&bpo=11205]: In dictionary displays, evaluate the key before the value.

bpo-24285 [https://bugs.python.org/issue?@action=redirect&bpo=24285]: Fixed regression that prevented importing extension modules from inside packages. Patch by Petr Viktorin.

Library

bpo-23247 [https://bugs.python.org/issue?@action=redirect&bpo=23247]: Fix a crash in the StreamWriter.reset() of CJK codecs.

bpo-24270 [https://bugs.python.org/issue?@action=redirect&bpo=24270]: Add math.isclose() and cmath.isclose() functions as per PEP 485 [https://peps.python.org/pep-0485/]. Contributed by Chris Barker and Tal Einat.

bpo-5633 [https://bugs.python.org/issue?@action=redirect&bpo=5633]: Fixed timeit when the statement is a string and the setup is not.

bpo-24326 [https://bugs.python.org/issue?@action=redirect&bpo=24326]: Fixed audioop.ratecv() with non-default weightB argument. Original patch by David Moore.

bpo-16991 [https://bugs.python.org/issue?@action=redirect&bpo=16991]: Add a C implementation of OrderedDict.

bpo-23934 [https://bugs.python.org/issue?@action=redirect&bpo=23934]: Fix inspect.signature to fail correctly for builtin types lacking signature information. Initial patch by James Powell.

Python 3.5.0 beta 1

Release date: 2015-05-24

Core and Builtins

bpo-24276 [https://bugs.python.org/issue?@action=redirect&bpo=24276]: Fixed optimization of property descriptor getter.

bpo-24268 [https://bugs.python.org/issue?@action=redirect&bpo=24268]: PEP 489: Multi-phase extension module initialization. Patch by Petr Viktorin.

bpo-23955 [https://bugs.python.org/issue?@action=redirect&bpo=23955]: Add pyvenv.cfg option to suppress registry/environment lookup for generating sys.path on Windows.

bpo-24257 [https://bugs.python.org/issue?@action=redirect&bpo=24257]: Fixed system error in the comparison of faked types.SimpleNamespace.

bpo-22939 [https://bugs.python.org/issue?@action=redirect&bpo=22939]: Fixed integer overflow in iterator object. Patch by Clement Rouault.

bpo-23985 [https://bugs.python.org/issue?@action=redirect&bpo=23985]: Fix a possible buffer overrun when deleting a slice from the front of a bytearray and then appending some other bytes data.

bpo-24102 [https://bugs.python.org/issue?@action=redirect&bpo=24102]: Fixed exception type checking in standard error handlers.

bpo-15027 [https://bugs.python.org/issue?@action=redirect&bpo=15027]: The UTF-32 encoder is now 3x to 7x faster.

bpo-23290 [https://bugs.python.org/issue?@action=redirect&bpo=23290]: Optimize set_merge() for cases where the target is empty. (Contributed by Serhiy Storchaka.)

bpo-2292 [https://bugs.python.org/issue?@action=redirect&bpo=2292]: PEP 448: Additional Unpacking Generalizations.

bpo-24096 [https://bugs.python.org/issue?@action=redirect&bpo=24096]: Make warnings.warn_explicit more robust against mutation of the warnings.filters list.

bpo-23996 [https://bugs.python.org/issue?@action=redirect&bpo=23996]: Avoid a crash when a delegated generator raises an unnormalized StopIteration exception. Patch by Stefan Behnel.

bpo-23910 [https://bugs.python.org/issue?@action=redirect&bpo=23910]: Optimize property() getter calls. Patch by Joe Jevnik.

bpo-23911 [https://bugs.python.org/issue?@action=redirect&bpo=23911]: Move path-based importlib bootstrap code to a separate frozen module.

bpo-24192 [https://bugs.python.org/issue?@action=redirect&bpo=24192]: Fix namespace package imports.

bpo-24022 [https://bugs.python.org/issue?@action=redirect&bpo=24022]: Fix tokenizer crash when processing undecodable source code.

bpo-9951 [https://bugs.python.org/issue?@action=redirect&bpo=9951]: Added a hex() method to bytes, bytearray, and memoryview.

bpo-22906 [https://bugs.python.org/issue?@action=redirect&bpo=22906]: PEP 479: Change StopIteration handling inside generators.

bpo-24017 [https://bugs.python.org/issue?@action=redirect&bpo=24017]: PEP 492: Coroutines with async and await syntax.

Library

bpo-14373 [https://bugs.python.org/issue?@action=redirect&bpo=14373]: Added C implementation of functools.lru_cache(). Based on patches by Matt Joiner and Alexey Kachayev.

bpo-24230 [https://bugs.python.org/issue?@action=redirect&bpo=24230]: The tempfile module now accepts bytes for prefix, suffix and dir parameters and returns bytes in such situations (matching the os module APIs).

bpo-22189 [https://bugs.python.org/issue?@action=redirect&bpo=22189]: collections.UserString now supports __getnewargs__(), __rmod__(), casefold(), format_map(), isprintable(), and maketrans(). Patch by Joe Jevnik.

bpo-24244 [https://bugs.python.org/issue?@action=redirect&bpo=24244]: Prevents termination when an invalid format string is encountered on Windows in strftime.

bpo-23973 [https://bugs.python.org/issue?@action=redirect&bpo=23973]: PEP 484: Add the typing module.

bpo-23086 [https://bugs.python.org/issue?@action=redirect&bpo=23086]: The collections.abc.Sequence() abstract base class added start and stop parameters to the index() mixin. Patch by Devin Jeanpierre.

bpo-20035 [https://bugs.python.org/issue?@action=redirect&bpo=20035]: Replaced the tkinter._fix module used for setting up the Tcl/Tk environment on Windows with a private function in the _tkinter module that makes no permanent changes to the environment.

bpo-24257 [https://bugs.python.org/issue?@action=redirect&bpo=24257]: Fixed segmentation fault in sqlite3.Row constructor with faked cursor type.

bpo-15836 [https://bugs.python.org/issue?@action=redirect&bpo=15836]: assertRaises(), assertRaisesRegex(), assertWarns() and assertWarnsRegex() assertments now check the type of the first argument to prevent possible user error. Based on patch by Daniel Wagner-Hall.

bpo-9858 [https://bugs.python.org/issue?@action=redirect&bpo=9858]: Add missing method stubs to _io.RawIOBase. Patch by Laura Rupprecht.

bpo-22955 [https://bugs.python.org/issue?@action=redirect&bpo=22955]: attrgetter, itemgetter and methodcaller objects in the operator module now support pickling. Added readable and evaluable repr for these objects. Based on patch by Josh Rosenberg.

bpo-22107 [https://bugs.python.org/issue?@action=redirect&bpo=22107]: tempfile.gettempdir() and tempfile.mkdtemp() now try again when a directory with the chosen name already exists on Windows as well as on Unix. tempfile.mkstemp() now fails early if parent directory is not valid (not exists or is a file) on Windows.

bpo-23780 [https://bugs.python.org/issue?@action=redirect&bpo=23780]: Improved error message in os.path.join() with single argument.

bpo-6598 [https://bugs.python.org/issue?@action=redirect&bpo=6598]: Increased time precision and random number range in email.utils.make_msgid() to strengthen the uniqueness of the message ID.

bpo-24091 [https://bugs.python.org/issue?@action=redirect&bpo=24091]: Fixed various crashes in corner cases in C implementation of ElementTree.

bpo-21931 [https://bugs.python.org/issue?@action=redirect&bpo=21931]: msilib.FCICreate() now raises TypeError in the case of a bad argument instead of a ValueError with a bogus FCI error number. Patch by Jeffrey Armstrong.

bpo-13866 [https://bugs.python.org/issue?@action=redirect&bpo=13866]: quote_via argument added to urllib.parse.urlencode.

bpo-20098 [https://bugs.python.org/issue?@action=redirect&bpo=20098]: New mangle_from policy option for email, default True for compat32, but False for all other policies.

bpo-24211 [https://bugs.python.org/issue?@action=redirect&bpo=24211]: The email library now supports RFC 6532: it can generate headers using utf-8 instead of encoded words.

bpo-16314 [https://bugs.python.org/issue?@action=redirect&bpo=16314]: Added support for the LZMA compression in distutils.

bpo-21804 [https://bugs.python.org/issue?@action=redirect&bpo=21804]: poplib now supports RFC 6856 (UTF8).

bpo-18682 [https://bugs.python.org/issue?@action=redirect&bpo=18682]: Optimized pprint functions for builtin scalar types.

bpo-22027 [https://bugs.python.org/issue?@action=redirect&bpo=22027]: smtplib now supports RFC 6531 (SMTPUTF8).

bpo-23488 [https://bugs.python.org/issue?@action=redirect&bpo=23488]: Random generator objects now consume 2x less memory on 64-bit.

bpo-1322 [https://bugs.python.org/issue?@action=redirect&bpo=1322]: platform.dist() and platform.linux_distribution() functions are now deprecated. Initial patch by Vajrasky Kok.

bpo-22486 [https://bugs.python.org/issue?@action=redirect&bpo=22486]: Added the math.gcd() function. The fractions.gcd() function now is deprecated. Based on patch by Mark Dickinson.

bpo-24064 [https://bugs.python.org/issue?@action=redirect&bpo=24064]: Property() docstrings are now writeable. (Patch by Berker Peksag.)

bpo-22681 [https://bugs.python.org/issue?@action=redirect&bpo=22681]: Added support for the koi8_t encoding.

bpo-22682 [https://bugs.python.org/issue?@action=redirect&bpo=22682]: Added support for the kz1048 encoding.

bpo-23796 [https://bugs.python.org/issue?@action=redirect&bpo=23796]: peek and read1 methods of BufferedReader now raise ValueError if they called on a closed object. Patch by John Hergenroeder.

bpo-21795 [https://bugs.python.org/issue?@action=redirect&bpo=21795]: smtpd now supports the 8BITMIME extension whenever the new decode_data constructor argument is set to False.

bpo-24155 [https://bugs.python.org/issue?@action=redirect&bpo=24155]: optimize heapq.heapify() for better cache performance when heapifying large lists.

bpo-21800 [https://bugs.python.org/issue?@action=redirect&bpo=21800]: imaplib now supports RFC 5161 (enable), RFC 6855 (utf8/internationalized email) and automatically encodes non-ASCII usernames and passwords to UTF8.

bpo-20274 [https://bugs.python.org/issue?@action=redirect&bpo=20274]: When calling a _sqlite.Connection, it now complains if passed any keyword arguments. Previously it silently ignored them.

bpo-20274 [https://bugs.python.org/issue?@action=redirect&bpo=20274]: Remove ignored and erroneous “kwargs” parameters from three METH_VARARGS methods on _sqlite.Connection.

bpo-24134 [https://bugs.python.org/issue?@action=redirect&bpo=24134]: assertRaises(), assertRaisesRegex(), assertWarns() and assertWarnsRegex() checks now emits a deprecation warning when callable is None or keyword arguments except msg is passed in the context manager mode.

bpo-24018 [https://bugs.python.org/issue?@action=redirect&bpo=24018]: Add a collections.abc.Generator abstract base class. Contributed by Stefan Behnel.

bpo-23880 [https://bugs.python.org/issue?@action=redirect&bpo=23880]: Tkinter’s getint() and getdouble() now support Tcl_Obj. Tkinter’s getdouble() now supports any numbers (in particular int).

bpo-22619 [https://bugs.python.org/issue?@action=redirect&bpo=22619]: Added negative limit support in the traceback module. Based on patch by Dmitry Kazakov.

bpo-24094 [https://bugs.python.org/issue?@action=redirect&bpo=24094]: Fix possible crash in json.encode with poorly behaved dict subclasses.

bpo-9246 [https://bugs.python.org/issue?@action=redirect&bpo=9246]: On POSIX, os.getcwd() now supports paths longer than 1025 bytes. Patch written by William Orr.

bpo-17445 [https://bugs.python.org/issue?@action=redirect&bpo=17445]: add difflib.diff_bytes() to support comparison of byte strings (fixes a regression from Python 2).

bpo-23917 [https://bugs.python.org/issue?@action=redirect&bpo=23917]: Fall back to sequential compilation when ProcessPoolExecutor doesn’t exist. Patch by Claudiu Popa.

bpo-23008 [https://bugs.python.org/issue?@action=redirect&bpo=23008]: Fixed resolving attributes with boolean value is False in pydoc.

Fix asyncio issue 235: LifoQueue and PriorityQueue’s put didn’t increment unfinished tasks (this bug was introduced when JoinableQueue was merged with Queue).

bpo-23908 [https://bugs.python.org/issue?@action=redirect&bpo=23908]: os functions now reject paths with embedded null character on Windows instead of silently truncating them.

bpo-23728 [https://bugs.python.org/issue?@action=redirect&bpo=23728]: binascii.crc_hqx() could return an integer outside of the range 0-0xffff for empty data.

bpo-23887 [https://bugs.python.org/issue?@action=redirect&bpo=23887]: urllib.error.HTTPError now has a proper repr() representation. Patch by Berker Peksag.

asyncio: New event loop APIs: set_task_factory() and get_task_factory().

asyncio: async() function is deprecated in favour of ensure_future().

bpo-24178 [https://bugs.python.org/issue?@action=redirect&bpo=24178]: asyncio.Lock, Condition, Semaphore, and BoundedSemaphore support new ‘async with’ syntax. Contributed by Yury Selivanov.

bpo-24179 [https://bugs.python.org/issue?@action=redirect&bpo=24179]: Support ‘async for’ for asyncio.StreamReader. Contributed by Yury Selivanov.

bpo-24184 [https://bugs.python.org/issue?@action=redirect&bpo=24184]: Add AsyncIterator and AsyncIterable ABCs to collections.abc. Contributed by Yury Selivanov.

bpo-22547 [https://bugs.python.org/issue?@action=redirect&bpo=22547]: Implement informative __repr__ for inspect.BoundArguments. Contributed by Yury Selivanov.

bpo-24190 [https://bugs.python.org/issue?@action=redirect&bpo=24190]: Implement inspect.BoundArgument.apply_defaults() method. Contributed by Yury Selivanov.

bpo-20691 [https://bugs.python.org/issue?@action=redirect&bpo=20691]: Add ‘follow_wrapped’ argument to inspect.Signature.from_callable() and inspect.signature(). Contributed by Yury Selivanov.

bpo-24248 [https://bugs.python.org/issue?@action=redirect&bpo=24248]: Deprecate inspect.Signature.from_function() and inspect.Signature.from_builtin().

bpo-23898 [https://bugs.python.org/issue?@action=redirect&bpo=23898]: Fix inspect.classify_class_attrs() to support attributes with overloaded __eq__ and __bool__. Patch by Mike Bayer.

bpo-24298 [https://bugs.python.org/issue?@action=redirect&bpo=24298]: Fix inspect.signature() to correctly unwrap wrappers around bound methods.

IDLE

bpo-23184 [https://bugs.python.org/issue?@action=redirect&bpo=23184]: remove unused names and imports in idlelib. Initial patch by Al Sweigart.

Tests

bpo-21520 [https://bugs.python.org/issue?@action=redirect&bpo=21520]: test_zipfile no longer fails if the word ‘bad’ appears anywhere in the name of the current directory.

bpo-9517 [https://bugs.python.org/issue?@action=redirect&bpo=9517]: Move script_helper into the support package. Patch by Christie Wilson.

Documentation

bpo-22155 [https://bugs.python.org/issue?@action=redirect&bpo=22155]: Add File Handlers subsection with createfilehandler to tkinter doc. Remove obsolete example from FAQ. Patch by Martin Panter.

bpo-24029 [https://bugs.python.org/issue?@action=redirect&bpo=24029]: Document the name binding behavior for submodule imports.

bpo-24077 [https://bugs.python.org/issue?@action=redirect&bpo=24077]: Fix typo in man page for -I command option: -s, not -S

Tools/Demos

bpo-24000 [https://bugs.python.org/issue?@action=redirect&bpo=24000]: Improved Argument Clinic’s mapping of converters to legacy “format units”. Updated the documentation to match.

bpo-24001 [https://bugs.python.org/issue?@action=redirect&bpo=24001]: Argument Clinic converters now use accept={type} instead of types={‘type’} to specify the types the converter accepts.

bpo-23330 [https://bugs.python.org/issue?@action=redirect&bpo=23330]: h2py now supports arbitrary filenames in #include.

bpo-24031 [https://bugs.python.org/issue?@action=redirect&bpo=24031]: make patchcheck now supports git checkouts, too.

Python 3.5.0 alpha 4

Release date: 2015-04-19

Core and Builtins

bpo-22980 [https://bugs.python.org/issue?@action=redirect&bpo=22980]: Under Linux, GNU/KFreeBSD and the Hurd, C extensions now include the architecture triplet in the extension name, to make it easy to test builds for different ABIs in the same working tree. Under OS X, the extension name now includes PEP 3149 [https://peps.python.org/pep-3149/]-style information.

bpo-22631 [https://bugs.python.org/issue?@action=redirect&bpo=22631]: Added Linux-specific socket constant CAN_RAW_FD_FRAMES. Patch courtesy of Joe Jevnik.

bpo-23731 [https://bugs.python.org/issue?@action=redirect&bpo=23731]: Implement PEP 488 [https://peps.python.org/pep-0488/]: removal of .pyo files.

bpo-23726 [https://bugs.python.org/issue?@action=redirect&bpo=23726]: Don’t enable GC for user subclasses of non-GC types that don’t add any new fields. Patch by Eugene Toder.

bpo-23309 [https://bugs.python.org/issue?@action=redirect&bpo=23309]: Avoid a deadlock at shutdown if a daemon thread is aborted while it is holding a lock to a buffered I/O object, and the main thread tries to use the same I/O object (typically stdout or stderr). A fatal error is emitted instead.

bpo-22977 [https://bugs.python.org/issue?@action=redirect&bpo=22977]: Fixed formatting Windows error messages on Wine. Patch by Martin Panter.

bpo-23466 [https://bugs.python.org/issue?@action=redirect&bpo=23466]: %c, %o, %x, and %X in bytes formatting now raise TypeError on non-integer input.

bpo-24044 [https://bugs.python.org/issue?@action=redirect&bpo=24044]: Fix possible null pointer dereference in list.sort in out of memory conditions.

bpo-21354 [https://bugs.python.org/issue?@action=redirect&bpo=21354]: PyCFunction_New function is exposed by python DLL again.

Library

bpo-23840 [https://bugs.python.org/issue?@action=redirect&bpo=23840]: tokenize.open() now closes the temporary binary file on error to fix a resource warning.

bpo-16914 [https://bugs.python.org/issue?@action=redirect&bpo=16914]: new debuglevel 2 in smtplib adds timestamps to debug output.

bpo-7159 [https://bugs.python.org/issue?@action=redirect&bpo=7159]: urllib.request now supports sending auth credentials automatically after the first 401. This enhancement is a superset of the enhancement from bpo-19494 [https://bugs.python.org/issue?@action=redirect&bpo=19494] and supersedes that change.

bpo-23703 [https://bugs.python.org/issue?@action=redirect&bpo=23703]: Fix a regression in urljoin() introduced in 901e4e52b20a. Patch by Demian Brecht.

bpo-4254 [https://bugs.python.org/issue?@action=redirect&bpo=4254]: Adds _curses.update_lines_cols(). Patch by Arnon Yaari

bpo-19933 [https://bugs.python.org/issue?@action=redirect&bpo=19933]: Provide default argument for ndigits in round. Patch by Vajrasky Kok.

bpo-23193 [https://bugs.python.org/issue?@action=redirect&bpo=23193]: Add a numeric_owner parameter to tarfile.TarFile.extract and tarfile.TarFile.extractall. Patch by Michael Vogt and Eric Smith.

bpo-23342 [https://bugs.python.org/issue?@action=redirect&bpo=23342]: Add a subprocess.run() function than returns a CalledProcess instance for a more consistent API than the existing call* functions.

bpo-21217 [https://bugs.python.org/issue?@action=redirect&bpo=21217]: inspect.getsourcelines() now tries to compute the start and end lines from the code object, fixing an issue when a lambda function is used as decorator argument. Patch by Thomas Ballinger and Allison Kaptur.

bpo-24521 [https://bugs.python.org/issue?@action=redirect&bpo=24521]: Fix possible integer overflows in the pickle module.

bpo-22931 [https://bugs.python.org/issue?@action=redirect&bpo=22931]: Allow ‘[’ and ‘]’ in cookie values.

The keywords attribute of functools.partial is now always a dictionary.

bpo-23811 [https://bugs.python.org/issue?@action=redirect&bpo=23811]: Add missing newline to the PyCompileError error message. Patch by Alex Shkop.

bpo-21116 [https://bugs.python.org/issue?@action=redirect&bpo=21116]: Avoid blowing memory when allocating a multiprocessing shared array that’s larger than 50% of the available RAM. Patch by Médéric Boquien.

bpo-22982 [https://bugs.python.org/issue?@action=redirect&bpo=22982]: Improve BOM handling when seeking to multiple positions of a writable text file.

bpo-23464 [https://bugs.python.org/issue?@action=redirect&bpo=23464]: Removed deprecated asyncio JoinableQueue.

bpo-23529 [https://bugs.python.org/issue?@action=redirect&bpo=23529]: Limit the size of decompressed data when reading from GzipFile, BZ2File or LZMAFile. This defeats denial of service attacks using compressed bombs (i.e. compressed payloads which decompress to a huge size). Patch by Martin Panter and Nikolaus Rath.

bpo-21859 [https://bugs.python.org/issue?@action=redirect&bpo=21859]: Added Python implementation of io.FileIO.

bpo-23865 [https://bugs.python.org/issue?@action=redirect&bpo=23865]: close() methods in multiple modules now are idempotent and more robust at shutdown. If they need to release multiple resources, all are released even if errors occur.

bpo-23400 [https://bugs.python.org/issue?@action=redirect&bpo=23400]: Raise same exception on both Python 2 and 3 if sem_open is not available. Patch by Davin Potts.

bpo-10838 [https://bugs.python.org/issue?@action=redirect&bpo=10838]: The subprocess now module includes SubprocessError and TimeoutError in its list of exported names for the users wild enough to use from subprocess import *.

bpo-23411 [https://bugs.python.org/issue?@action=redirect&bpo=23411]: Added DefragResult, ParseResult, SplitResult, DefragResultBytes, ParseResultBytes, and SplitResultBytes to urllib.parse.__all__. Patch by Martin Panter.

bpo-23881 [https://bugs.python.org/issue?@action=redirect&bpo=23881]: urllib.request.ftpwrapper constructor now closes the socket if the FTP connection failed to fix a ResourceWarning.

bpo-23853 [https://bugs.python.org/issue?@action=redirect&bpo=23853]: socket.socket.sendall() does no more reset the socket timeout each time data is sent successfully. The socket timeout is now the maximum total duration to send all data.

bpo-22721 [https://bugs.python.org/issue?@action=redirect&bpo=22721]: An order of multiline pprint output of set or dict containing orderable and non-orderable elements no longer depends on iteration order of set or dict.

bpo-15133 [https://bugs.python.org/issue?@action=redirect&bpo=15133]: _tkinter.tkapp.getboolean() now supports Tcl_Obj and always returns bool. tkinter.BooleanVar now validates input values (accepted bool, int, str, and Tcl_Obj). tkinter.BooleanVar.get() now always returns bool.

bpo-10590 [https://bugs.python.org/issue?@action=redirect&bpo=10590]: xml.sax.parseString() now supports string argument.

bpo-23338 [https://bugs.python.org/issue?@action=redirect&bpo=23338]: Fixed formatting ctypes error messages on Cygwin. Patch by Makoto Kato.

bpo-15582 [https://bugs.python.org/issue?@action=redirect&bpo=15582]: inspect.getdoc() now follows inheritance chains.

bpo-2175 [https://bugs.python.org/issue?@action=redirect&bpo=2175]: SAX parsers now support a character stream of InputSource object.

bpo-16840 [https://bugs.python.org/issue?@action=redirect&bpo=16840]: Tkinter now supports 64-bit integers added in Tcl 8.4 and arbitrary precision integers added in Tcl 8.5.

bpo-23834 [https://bugs.python.org/issue?@action=redirect&bpo=23834]: Fix socket.sendto(), use the C Py_ssize_t type to store the result of sendto() instead of the C int type.

bpo-23618 [https://bugs.python.org/issue?@action=redirect&bpo=23618]: socket.socket.connect() now waits until the connection completes instead of raising InterruptedError if the connection is interrupted by signals, signal handlers don’t raise an exception and the socket is blocking or has a timeout. socket.socket.connect() still raise InterruptedError for non-blocking sockets.

bpo-21526 [https://bugs.python.org/issue?@action=redirect&bpo=21526]: Tkinter now supports new boolean type in Tcl 8.5.

bpo-23836 [https://bugs.python.org/issue?@action=redirect&bpo=23836]: Fix the faulthandler module to handle reentrant calls to its signal handlers.

bpo-23838 [https://bugs.python.org/issue?@action=redirect&bpo=23838]: linecache now clears the cache and returns an empty result on MemoryError.

bpo-10395 [https://bugs.python.org/issue?@action=redirect&bpo=10395]: Added os.path.commonpath(). Implemented in posixpath and ntpath. Based on patch by Rafik Draoui.

bpo-23611 [https://bugs.python.org/issue?@action=redirect&bpo=23611]: Serializing more “lookupable” objects (such as unbound methods or nested classes) now are supported with pickle protocols < 4.

bpo-13583 [https://bugs.python.org/issue?@action=redirect&bpo=13583]: sqlite3.Row now supports slice indexing.

bpo-18473 [https://bugs.python.org/issue?@action=redirect&bpo=18473]: Fixed 2to3 and 3to2 compatible pickle mappings. Fixed ambiguous reverse mappings. Added many new mappings. Import mapping is no longer applied to modules already mapped with full name mapping.

bpo-23485 [https://bugs.python.org/issue?@action=redirect&bpo=23485]: select.select() is now retried automatically with the recomputed timeout when interrupted by a signal, except if the signal handler raises an exception. This change is part of the PEP 475 [https://peps.python.org/pep-0475/].

bpo-23752 [https://bugs.python.org/issue?@action=redirect&bpo=23752]: When built from an existing file descriptor, io.FileIO() now only calls fstat() once. Before fstat() was called twice, which was not necessary.

bpo-23704 [https://bugs.python.org/issue?@action=redirect&bpo=23704]: collections.deque() objects now support __add__, __mul__, and __imul__().

bpo-23171 [https://bugs.python.org/issue?@action=redirect&bpo=23171]: csv.Writer.writerow() now supports arbitrary iterables.

bpo-23745 [https://bugs.python.org/issue?@action=redirect&bpo=23745]: The new email header parser now handles duplicate MIME parameter names without error, similar to how get_param behaves.

bpo-22117 [https://bugs.python.org/issue?@action=redirect&bpo=22117]: Fix os.utime(), it now rounds the timestamp towards minus infinity (-inf) instead of rounding towards zero.

bpo-23310 [https://bugs.python.org/issue?@action=redirect&bpo=23310]: Fix MagicMock’s initializer to work with __methods__, just like configure_mock(). Patch by Kasia Jachim.

Build

bpo-23817 [https://bugs.python.org/issue?@action=redirect&bpo=23817]: FreeBSD now uses “1.0” in the SOVERSION as other operating systems, instead of just “1”.

bpo-23501 [https://bugs.python.org/issue?@action=redirect&bpo=23501]: Argument Clinic now generates code into separate files by default.

Tests

bpo-23799 [https://bugs.python.org/issue?@action=redirect&bpo=23799]: Added test.support.start_threads() for running and cleaning up multiple threads.

bpo-22390 [https://bugs.python.org/issue?@action=redirect&bpo=22390]: test.regrtest now emits a warning if temporary files or directories are left after running a test.

Tools/Demos

bpo-18128 [https://bugs.python.org/issue?@action=redirect&bpo=18128]: pygettext now uses standard +NNNN format in the POT-Creation-Date header.

bpo-23935 [https://bugs.python.org/issue?@action=redirect&bpo=23935]: Argument Clinic’s understanding of format units accepting bytes, bytearrays, and buffers is now consistent with both the documentation and the implementation.

bpo-23944 [https://bugs.python.org/issue?@action=redirect&bpo=23944]: Argument Clinic now wraps long impl prototypes at column 78.

bpo-20586 [https://bugs.python.org/issue?@action=redirect&bpo=20586]: Argument Clinic now ensures that functions without docstrings have signatures.

bpo-23492 [https://bugs.python.org/issue?@action=redirect&bpo=23492]: Argument Clinic now generates argument parsing code with PyArg_Parse instead of PyArg_ParseTuple if possible.

bpo-23500 [https://bugs.python.org/issue?@action=redirect&bpo=23500]: Argument Clinic is now smarter about generating the “#ifndef” (empty) definition of the methoddef macro: it’s only generated once, even if Argument Clinic processes the same symbol multiple times, and it’s emitted at the end of all processing rather than immediately after the first use.

C API

bpo-23998 [https://bugs.python.org/issue?@action=redirect&bpo=23998]: PyImport_ReInitLock() now checks for lock allocation error

Python 3.5.0 alpha 3

Release date: 2015-03-28

Core and Builtins

bpo-23573 [https://bugs.python.org/issue?@action=redirect&bpo=23573]: Increased performance of string search operations (str.find, str.index, str.count, the in operator, str.split, str.partition) with arguments of different kinds (UCS1, UCS2, UCS4).

bpo-23753 [https://bugs.python.org/issue?@action=redirect&bpo=23753]: Python doesn’t support anymore platforms without stat() or fstat(), these functions are always required.

bpo-23681 [https://bugs.python.org/issue?@action=redirect&bpo=23681]: The -b option now affects comparisons of bytes with int.

bpo-23632 [https://bugs.python.org/issue?@action=redirect&bpo=23632]: Memoryviews now allow tuple indexing (including for multi-dimensional memoryviews).

bpo-23192 [https://bugs.python.org/issue?@action=redirect&bpo=23192]: Fixed generator lambdas. Patch by Bruno Cauet.

bpo-23629 [https://bugs.python.org/issue?@action=redirect&bpo=23629]: Fix the default __sizeof__ implementation for variable-sized objects.

Library

bpo-14260 [https://bugs.python.org/issue?@action=redirect&bpo=14260]: The groupindex attribute of regular expression pattern object now is non-modifiable mapping.

bpo-23792 [https://bugs.python.org/issue?@action=redirect&bpo=23792]: Ignore KeyboardInterrupt when the pydoc pager is active. This mimics the behavior of the standard unix pagers, and prevents pipepager from shutting down while the pager itself is still running.

bpo-23775 [https://bugs.python.org/issue?@action=redirect&bpo=23775]: pprint() of OrderedDict now outputs the same representation as repr().

bpo-23765 [https://bugs.python.org/issue?@action=redirect&bpo=23765]: Removed IsBadStringPtr calls in ctypes

bpo-22364 [https://bugs.python.org/issue?@action=redirect&bpo=22364]: Improved some re error messages using regex for hints.

bpo-23742 [https://bugs.python.org/issue?@action=redirect&bpo=23742]: ntpath.expandvars() no longer loses unbalanced single quotes.

bpo-21717 [https://bugs.python.org/issue?@action=redirect&bpo=21717]: The zipfile.ZipFile.open function now supports ‘x’ (exclusive creation) mode.

bpo-21802 [https://bugs.python.org/issue?@action=redirect&bpo=21802]: The reader in BufferedRWPair now is closed even when closing writer failed in BufferedRWPair.close().

bpo-23622 [https://bugs.python.org/issue?@action=redirect&bpo=23622]: Unknown escapes in regular expressions that consist of '\' and ASCII letter now raise a deprecation warning and will be forbidden in Python 3.6.

bpo-23671 [https://bugs.python.org/issue?@action=redirect&bpo=23671]: string.Template now allows specifying the “self” parameter as a keyword argument. string.Formatter now allows specifying the “self” and the “format_string” parameters as keyword arguments.

bpo-23502 [https://bugs.python.org/issue?@action=redirect&bpo=23502]: The pprint module now supports mapping proxies.

bpo-17530 [https://bugs.python.org/issue?@action=redirect&bpo=17530]: pprint now wraps long bytes objects and bytearrays.

bpo-22687 [https://bugs.python.org/issue?@action=redirect&bpo=22687]: Fixed some corner cases in breaking words in tetxtwrap. Got rid of quadratic complexity in breaking long words.

bpo-4727 [https://bugs.python.org/issue?@action=redirect&bpo=4727]: The copy module now uses pickle protocol 4 (PEP 3154) and supports copying of instances of classes whose __new__ method takes keyword-only arguments.

bpo-23491 [https://bugs.python.org/issue?@action=redirect&bpo=23491]: Added a zipapp module to support creating executable zip file archives of Python code. Registered “.pyz” and “.pyzw” extensions on Windows for these archives (PEP 441).

bpo-23657 [https://bugs.python.org/issue?@action=redirect&bpo=23657]: Avoid explicit checks for str in zipapp, adding support for pathlib.Path objects as arguments.

bpo-23688 [https://bugs.python.org/issue?@action=redirect&bpo=23688]: Added support of arbitrary bytes-like objects and avoided unnecessary copying of memoryview in gzip.GzipFile.write(). Original patch by Wolfgang Maier.

bpo-23252 [https://bugs.python.org/issue?@action=redirect&bpo=23252]: Added support for writing ZIP files to unseekable streams.

bpo-23647 [https://bugs.python.org/issue?@action=redirect&bpo=23647]: Increase imaplib’s MAXLINE to accommodate modern mailbox sizes.

bpo-23539 [https://bugs.python.org/issue?@action=redirect&bpo=23539]: If body is None, http.client.HTTPConnection.request now sets Content-Length to 0 for PUT, POST, and PATCH headers to avoid 411 errors from some web servers.

bpo-22351 [https://bugs.python.org/issue?@action=redirect&bpo=22351]: The nntplib.NNTP constructor no longer leaves the connection and socket open until the garbage collector cleans them up. Patch by Martin Panter.

bpo-23704 [https://bugs.python.org/issue?@action=redirect&bpo=23704]: collections.deque() objects now support methods for index(), insert(), and copy(). This allows deques to be registered as a MutableSequence and it improves their substitutability for lists.

bpo-23715 [https://bugs.python.org/issue?@action=redirect&bpo=23715]: signal.sigwaitinfo() and signal.sigtimedwait() are now retried when interrupted by a signal not in the sigset parameter, if the signal handler does not raise an exception. signal.sigtimedwait() recomputes the timeout with a monotonic clock when it is retried.

bpo-23001 [https://bugs.python.org/issue?@action=redirect&bpo=23001]: Few functions in modules mmap, ossaudiodev, socket, ssl, and codecs, that accepted only read-only bytes-like object now accept writable bytes-like object too.

bpo-23646 [https://bugs.python.org/issue?@action=redirect&bpo=23646]: If time.sleep() is interrupted by a signal, the sleep is now retried with the recomputed delay, except if the signal handler raises an exception (PEP 475).

bpo-23136 [https://bugs.python.org/issue?@action=redirect&bpo=23136]: _strptime now uniformly handles all days in week 0, including Dec 30 of previous year. Based on patch by Jim Carroll.

bpo-23700 [https://bugs.python.org/issue?@action=redirect&bpo=23700]: Iterator of NamedTemporaryFile now keeps a reference to NamedTemporaryFile instance. Patch by Bohuslav Kabrda.

bpo-22903 [https://bugs.python.org/issue?@action=redirect&bpo=22903]: The fake test case created by unittest.loader when it fails importing a test module is now picklable.

bpo-22181 [https://bugs.python.org/issue?@action=redirect&bpo=22181]: On Linux, os.urandom() now uses the new getrandom() syscall if available, syscall introduced in the Linux kernel 3.17. It is more reliable and more secure, because it avoids the need of a file descriptor and waits until the kernel has enough entropy.

bpo-2211 [https://bugs.python.org/issue?@action=redirect&bpo=2211]: Updated the implementation of the http.cookies.Morsel class. Setting attributes key, value and coded_value directly now is deprecated. update() and setdefault() now transform and check keys. Comparing for equality now takes into account attributes key, value and coded_value. copy() now returns a Morsel, not a dict. repr() now contains all attributes. Optimized checking keys and quoting values. Added new tests. Original patch by Demian Brecht.

bpo-18983 [https://bugs.python.org/issue?@action=redirect&bpo=18983]: Allow selection of output units in timeit. Patch by Julian Gindi.

bpo-23631 [https://bugs.python.org/issue?@action=redirect&bpo=23631]: Fix traceback.format_list when a traceback has been mutated.

bpo-23568 [https://bugs.python.org/issue?@action=redirect&bpo=23568]: Add rdivmod support to MagicMock() objects. Patch by Håkan Lövdahl.

bpo-2052 [https://bugs.python.org/issue?@action=redirect&bpo=2052]: Add charset parameter to HtmlDiff.make_file().

bpo-23668 [https://bugs.python.org/issue?@action=redirect&bpo=23668]: Support os.truncate and os.ftruncate on Windows.

bpo-23138 [https://bugs.python.org/issue?@action=redirect&bpo=23138]: Fixed parsing cookies with absent keys or values in cookiejar. Patch by Demian Brecht.

bpo-23051 [https://bugs.python.org/issue?@action=redirect&bpo=23051]: multiprocessing.Pool methods imap() and imap_unordered() now handle exceptions raised by an iterator. Patch by Alon Diamant and Davin Potts.

bpo-23581 [https://bugs.python.org/issue?@action=redirect&bpo=23581]: Add matmul support to MagicMock. Patch by Håkan Lövdahl.

bpo-23566 [https://bugs.python.org/issue?@action=redirect&bpo=23566]: enable(), register(), dump_traceback() and dump_traceback_later() functions of faulthandler now accept file descriptors. Patch by Wei Wu.

bpo-22928 [https://bugs.python.org/issue?@action=redirect&bpo=22928]: Disabled HTTP header injections in http.client. Original patch by Demian Brecht.

bpo-23615 [https://bugs.python.org/issue?@action=redirect&bpo=23615]: Modules bz2, tarfile and tokenize now can be reloaded with imp.reload(). Patch by Thomas Kluyver.

bpo-23605 [https://bugs.python.org/issue?@action=redirect&bpo=23605]: os.walk() now calls os.scandir() instead of os.listdir(). The usage of os.scandir() reduces the number of calls to os.stat(). Initial patch written by Ben Hoyt.

Build

bpo-23585 [https://bugs.python.org/issue?@action=redirect&bpo=23585]: make patchcheck will ensure the interpreter is built.

Tests

bpo-23583 [https://bugs.python.org/issue?@action=redirect&bpo=23583]: Added tests for standard IO streams in IDLE.

bpo-22289 [https://bugs.python.org/issue?@action=redirect&bpo=22289]: Prevent test_urllib2net failures due to ftp connection timeout.

Tools/Demos

bpo-22826 [https://bugs.python.org/issue?@action=redirect&bpo=22826]: The result of open() in Tools/freeze/bkfile.py is now better compatible with regular files (in particular it now supports the context management protocol).

Python 3.5.0 alpha 2

Release date: 2015-03-09

Core and Builtins

bpo-23571 [https://bugs.python.org/issue?@action=redirect&bpo=23571]: PyObject_Call() and PyCFunction_Call() now raise a SystemError if a function returns a result and raises an exception. The SystemError is chained to the previous exception.

Library

bpo-22524 [https://bugs.python.org/issue?@action=redirect&bpo=22524]: New os.scandir() function, part of the PEP 471 [https://peps.python.org/pep-0471/]: “os.scandir() function – a better and faster directory iterator”. Patch written by Ben Hoyt.

bpo-23103 [https://bugs.python.org/issue?@action=redirect&bpo=23103]: Reduced the memory consumption of IPv4Address and IPv6Address.

bpo-21793 [https://bugs.python.org/issue?@action=redirect&bpo=21793]: BaseHTTPRequestHandler again logs response code as numeric, not as stringified enum. Patch by Demian Brecht.

bpo-23476 [https://bugs.python.org/issue?@action=redirect&bpo=23476]: In the ssl module, enable OpenSSL’s X509_V_FLAG_TRUSTED_FIRST flag on certificate stores when it is available.

bpo-23576 [https://bugs.python.org/issue?@action=redirect&bpo=23576]: Avoid stalling in SSL reads when EOF has been reached in the SSL layer but the underlying connection hasn’t been closed.

bpo-23504 [https://bugs.python.org/issue?@action=redirect&bpo=23504]: Added an __all__ to the types module.

bpo-23563 [https://bugs.python.org/issue?@action=redirect&bpo=23563]: Optimized utility functions in urllib.parse.

bpo-7830 [https://bugs.python.org/issue?@action=redirect&bpo=7830]: Flatten nested functools.partial.

bpo-20204 [https://bugs.python.org/issue?@action=redirect&bpo=20204]: Added the __module__ attribute to _tkinter classes.

bpo-19980 [https://bugs.python.org/issue?@action=redirect&bpo=19980]: Improved help() for non-recognized strings. help(‘’) now shows the help on str. help(‘help’) now shows the help on help(). Original patch by Mark Lawrence.

bpo-23521 [https://bugs.python.org/issue?@action=redirect&bpo=23521]: Corrected pure python implementation of timedelta division. Eliminated OverflowError from timedelta * float for some floats; Corrected rounding in timedelta true division.

bpo-21619 [https://bugs.python.org/issue?@action=redirect&bpo=21619]: Popen objects no longer leave a zombie after exit in the with statement if the pipe was broken. Patch by Martin Panter.

bpo-22936 [https://bugs.python.org/issue?@action=redirect&bpo=22936]: Make it possible to show local variables in tracebacks for both the traceback module and unittest.

bpo-15955 [https://bugs.python.org/issue?@action=redirect&bpo=15955]: Add an option to limit the output size in bz2.decompress(). Patch by Nikolaus Rath.

bpo-6639 [https://bugs.python.org/issue?@action=redirect&bpo=6639]: Module-level turtle functions no longer raise TclError after closing the window.

bpo-814253 [https://bugs.python.org/issue?@action=redirect&bpo=814253]: Group references and conditional group references now work in lookbehind assertions in regular expressions. (See also: bpo-9179 [https://bugs.python.org/issue?@action=redirect&bpo=9179])

bpo-23215 [https://bugs.python.org/issue?@action=redirect&bpo=23215]: Multibyte codecs with custom error handlers that ignores errors consumed too much memory and raised SystemError or MemoryError. Original patch by Aleksi Torhamo.

bpo-5700 [https://bugs.python.org/issue?@action=redirect&bpo=5700]: io.FileIO() called flush() after closing the file. flush() was not called in close() if closefd=False.

bpo-23374 [https://bugs.python.org/issue?@action=redirect&bpo=23374]: Fixed pydoc failure with non-ASCII files when stdout encoding differs from file system encoding (e.g. on Mac OS).

bpo-23481 [https://bugs.python.org/issue?@action=redirect&bpo=23481]: Remove RC4 from the SSL module’s default cipher list.

bpo-21548 [https://bugs.python.org/issue?@action=redirect&bpo=21548]: Fix pydoc.synopsis() and pydoc.apropos() on modules with empty docstrings.

bpo-22885 [https://bugs.python.org/issue?@action=redirect&bpo=22885]: Fixed arbitrary code execution vulnerability in the dbm.dumb module. Original patch by Claudiu Popa.

bpo-23239 [https://bugs.python.org/issue?@action=redirect&bpo=23239]: ssl.match_hostname() now supports matching of IP addresses.

bpo-23146 [https://bugs.python.org/issue?@action=redirect&bpo=23146]: Fix mishandling of absolute Windows paths with forward slashes in pathlib.

bpo-23096 [https://bugs.python.org/issue?@action=redirect&bpo=23096]: Pickle representation of floats with protocol 0 now is the same for both Python and C implementations.

bpo-19105 [https://bugs.python.org/issue?@action=redirect&bpo=19105]: pprint now more efficiently uses free space at the right.

bpo-14910 [https://bugs.python.org/issue?@action=redirect&bpo=14910]: Add allow_abbrev parameter to argparse.ArgumentParser. Patch by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.

bpo-21717 [https://bugs.python.org/issue?@action=redirect&bpo=21717]: tarfile.open() now supports ‘x’ (exclusive creation) mode.

bpo-23344 [https://bugs.python.org/issue?@action=redirect&bpo=23344]: marshal.dumps() is now 20-25% faster on average.

bpo-20416 [https://bugs.python.org/issue?@action=redirect&bpo=20416]: marshal.dumps() with protocols 3 and 4 is now 40-50% faster on average.

bpo-23421 [https://bugs.python.org/issue?@action=redirect&bpo=23421]: Fixed compression in tarfile CLI. Patch by wdv4758h.

bpo-23367 [https://bugs.python.org/issue?@action=redirect&bpo=23367]: Fix possible overflows in the unicodedata module.

bpo-23361 [https://bugs.python.org/issue?@action=redirect&bpo=23361]: Fix possible overflow in Windows subprocess creation code.

logging.handlers.QueueListener now takes a respect_handler_level keyword argument which, if set to True, will pass messages to handlers taking handler levels into account.

bpo-19705 [https://bugs.python.org/issue?@action=redirect&bpo=19705]: turtledemo now has a visual sorting algorithm demo. Original patch from Jason Yeo.

bpo-23801 [https://bugs.python.org/issue?@action=redirect&bpo=23801]: Fix issue where cgi.FieldStorage did not always ignore the entire preamble to a multipart body.

Build

bpo-23445 [https://bugs.python.org/issue?@action=redirect&bpo=23445]: pydebug builds now use “gcc -Og” where possible, to make the resulting executable faster.

bpo-23686 [https://bugs.python.org/issue?@action=redirect&bpo=23686]: Update OS X 10.5 installer build to use OpenSSL 1.0.2a.

C API

bpo-20204 [https://bugs.python.org/issue?@action=redirect&bpo=20204]: Deprecation warning is now raised for builtin types without the __module__ attribute.

Windows

bpo-23465 [https://bugs.python.org/issue?@action=redirect&bpo=23465]: Implement PEP 486 [https://peps.python.org/pep-0486/] - Make the Python Launcher aware of virtual environments. Patch by Paul Moore.

bpo-23437 [https://bugs.python.org/issue?@action=redirect&bpo=23437]: Make user scripts directory versioned on Windows. Patch by Paul Moore.

Python 3.5.0 alpha 1

Release date: 2015-02-08

Core and Builtins

bpo-23285 [https://bugs.python.org/issue?@action=redirect&bpo=23285]: PEP 475 - EINTR handling.

bpo-22735 [https://bugs.python.org/issue?@action=redirect&bpo=22735]: Fix many edge cases (including crashes) involving custom mro() implementations.

bpo-22896 [https://bugs.python.org/issue?@action=redirect&bpo=22896]: Avoid using PyObject_AsCharBuffer(), PyObject_AsReadBuffer() and PyObject_AsWriteBuffer().

bpo-21295 [https://bugs.python.org/issue?@action=redirect&bpo=21295]: Revert some changes (bpo-16795 [https://bugs.python.org/issue?@action=redirect&bpo=16795]) to AST line numbers and column offsets that constituted a regression.

bpo-22986 [https://bugs.python.org/issue?@action=redirect&bpo=22986]: Allow changing an object’s __class__ between a dynamic type and static type in some cases.

bpo-15859 [https://bugs.python.org/issue?@action=redirect&bpo=15859]: PyUnicode_EncodeFSDefault(), PyUnicode_EncodeMBCS() and PyUnicode_EncodeCodePage() now raise an exception if the object is not a Unicode object. For PyUnicode_EncodeFSDefault(), it was already the case on platforms other than Windows. Patch written by Campbell Barton.

bpo-21408 [https://bugs.python.org/issue?@action=redirect&bpo=21408]: The default __ne__() now returns NotImplemented if __eq__() returned NotImplemented. Original patch by Martin Panter.

bpo-23321 [https://bugs.python.org/issue?@action=redirect&bpo=23321]: Fixed a crash in str.decode() when error handler returned replacement string longer than malformed input data.

bpo-22286 [https://bugs.python.org/issue?@action=redirect&bpo=22286]: The “backslashreplace” error handlers now works with decoding and translating.

bpo-23253 [https://bugs.python.org/issue?@action=redirect&bpo=23253]: Delay-load ShellExecute[AW] in os.startfile for reduced startup overhead on Windows.

bpo-22038 [https://bugs.python.org/issue?@action=redirect&bpo=22038]: pyatomic.h now uses stdatomic.h or GCC built-in functions for atomic memory access if available. Patch written by Vitor de Lima and Gustavo Temple.

bpo-20284 [https://bugs.python.org/issue?@action=redirect&bpo=20284]: %-interpolation (aka printf) formatting added for bytes and bytearray.

bpo-23048 [https://bugs.python.org/issue?@action=redirect&bpo=23048]: Fix jumping out of an infinite while loop in the pdb.

bpo-20335 [https://bugs.python.org/issue?@action=redirect&bpo=20335]: bytes constructor now raises TypeError when encoding or errors is specified with non-string argument. Based on patch by Renaud Blanch.

bpo-22834 [https://bugs.python.org/issue?@action=redirect&bpo=22834]: If the current working directory ends up being set to a non-existent directory then import will no longer raise FileNotFoundError.

bpo-22869 [https://bugs.python.org/issue?@action=redirect&bpo=22869]: Move the interpreter startup & shutdown code to a new dedicated pylifecycle.c module

bpo-22847 [https://bugs.python.org/issue?@action=redirect&bpo=22847]: Improve method cache efficiency.

bpo-22335 [https://bugs.python.org/issue?@action=redirect&bpo=22335]: Fix crash when trying to enlarge a bytearray to 0x7fffffff bytes on a 32-bit platform.

bpo-22653 [https://bugs.python.org/issue?@action=redirect&bpo=22653]: Fix an assertion failure in debug mode when doing a reentrant dict insertion in debug mode.

bpo-22643 [https://bugs.python.org/issue?@action=redirect&bpo=22643]: Fix integer overflow in Unicode case operations (upper, lower, title, swapcase, casefold).

bpo-17636 [https://bugs.python.org/issue?@action=redirect&bpo=17636]: Circular imports involving relative imports are now supported.

bpo-22604 [https://bugs.python.org/issue?@action=redirect&bpo=22604]: Fix assertion error in debug mode when dividing a complex number by (nan+0j).

bpo-21052 [https://bugs.python.org/issue?@action=redirect&bpo=21052]: Do not raise ImportWarning when sys.path_hooks or sys.meta_path are set to None.

bpo-16518 [https://bugs.python.org/issue?@action=redirect&bpo=16518]: Use ‘bytes-like object required’ in error messages that previously used the far more cryptic “‘x’ does not support the buffer protocol.

bpo-22470 [https://bugs.python.org/issue?@action=redirect&bpo=22470]: Fixed integer overflow issues in “backslashreplace”, “xmlcharrefreplace”, and “surrogatepass” error handlers.

bpo-22540 [https://bugs.python.org/issue?@action=redirect&bpo=22540]: speed up PyObject_IsInstance and PyObject_IsSubclass in the common case that the second argument has metaclass type.

bpo-18711 [https://bugs.python.org/issue?@action=redirect&bpo=18711]: Add a new PyErr_FormatV function, similar to PyErr_Format but accepting a va_list argument.

bpo-22520 [https://bugs.python.org/issue?@action=redirect&bpo=22520]: Fix overflow checking when generating the repr of a unicode object.

bpo-22519 [https://bugs.python.org/issue?@action=redirect&bpo=22519]: Fix overflow checking in PyBytes_Repr.

bpo-22518 [https://bugs.python.org/issue?@action=redirect&bpo=22518]: Fix integer overflow issues in latin-1 encoding.

bpo-16324 [https://bugs.python.org/issue?@action=redirect&bpo=16324]: _charset parameter of MIMEText now also accepts email.charset.Charset instances. Initial patch by Claude Paroz.

bpo-1764286 [https://bugs.python.org/issue?@action=redirect&bpo=1764286]: Fix inspect.getsource() to support decorated functions. Patch by Claudiu Popa.

bpo-18554 [https://bugs.python.org/issue?@action=redirect&bpo=18554]: os.__all__ includes posix functions.

bpo-21391 [https://bugs.python.org/issue?@action=redirect&bpo=21391]: Use os.path.abspath in the shutil module.

bpo-11471 [https://bugs.python.org/issue?@action=redirect&bpo=11471]: avoid generating a JUMP_FORWARD instruction at the end of an if-block if there is no else-clause. Original patch by Eugene Toder.

bpo-22215 [https://bugs.python.org/issue?@action=redirect&bpo=22215]: Now ValueError is raised instead of TypeError when str or bytes argument contains not permitted null character or byte.

bpo-22258 [https://bugs.python.org/issue?@action=redirect&bpo=22258]: Fix the internal function set_inheritable() on Illumos. This platform exposes the function ioctl(FIOCLEX), but calling it fails with errno is ENOTTY: “Inappropriate ioctl for device”. set_inheritable() now falls back to the slower fcntl() (F_GETFD and then F_SETFD).

bpo-21389 [https://bugs.python.org/issue?@action=redirect&bpo=21389]: Displaying the __qualname__ of the underlying function in the repr of a bound method.

bpo-22206 [https://bugs.python.org/issue?@action=redirect&bpo=22206]: Using pthread, PyThread_create_key() now sets errno to ENOMEM and returns -1 (error) on integer overflow.

bpo-20184 [https://bugs.python.org/issue?@action=redirect&bpo=20184]: Argument Clinic based signature introspection added for 30 of the builtin functions.

bpo-22116 [https://bugs.python.org/issue?@action=redirect&bpo=22116]: C functions and methods (of the ‘builtin_function_or_method’ type) can now be weakref’ed. Patch by Wei Wu.

bpo-22077 [https://bugs.python.org/issue?@action=redirect&bpo=22077]: Improve index error messages for bytearrays, bytes, lists, and tuples by adding ‘or slices’. Added ‘, not <typename>’ for bytearrays. Original patch by Claudiu Popa.

bpo-20179 [https://bugs.python.org/issue?@action=redirect&bpo=20179]: Apply Argument Clinic to bytes and bytearray. Patch by Tal Einat.

bpo-22082 [https://bugs.python.org/issue?@action=redirect&bpo=22082]: Clear interned strings in slotdefs.

Upgrade Unicode database to Unicode 7.0.0.

bpo-21897 [https://bugs.python.org/issue?@action=redirect&bpo=21897]: Fix a crash with the f_locals attribute with closure variables when frame.clear() has been called.

bpo-21205 [https://bugs.python.org/issue?@action=redirect&bpo=21205]: Add a new __qualname__ attribute to generator, the qualified name, and use it in the representation of a generator (repr(gen)). The default name of the generator (__name__ attribute) is now get from the function instead of the code. Use gen.gi_code.co_name to get the name of the code.

bpo-21669 [https://bugs.python.org/issue?@action=redirect&bpo=21669]: With the aid of heuristics in SyntaxError.__init__, the parser now attempts to generate more meaningful (or at least more search engine friendly) error messages when “exec” and “print” are used as statements.

bpo-21642 [https://bugs.python.org/issue?@action=redirect&bpo=21642]: In the conditional if-else expression, allow an integer written with no space between itself and the else keyword (e.g. True if 42else False) to be valid syntax.

bpo-21523 [https://bugs.python.org/issue?@action=redirect&bpo=21523]: Fix over-pessimistic computation of the stack effect of some opcodes in the compiler. This also fixes a quadratic compilation time issue noticeable when compiling code with a large number of “and” and “or” operators.

bpo-21418 [https://bugs.python.org/issue?@action=redirect&bpo=21418]: Fix a crash in the builtin function super() when called without argument and without current frame (ex: embedded Python).

bpo-21425 [https://bugs.python.org/issue?@action=redirect&bpo=21425]: Fix flushing of standard streams in the interactive interpreter.

bpo-21435 [https://bugs.python.org/issue?@action=redirect&bpo=21435]: In rare cases, when running finalizers on objects in cyclic trash a bad pointer dereference could occur due to a subtle flaw in internal iteration logic.

bpo-21377 [https://bugs.python.org/issue?@action=redirect&bpo=21377]: PyBytes_Concat() now tries to concatenate in-place when the first argument has a reference count of 1. Patch by Nikolaus Rath.

bpo-20355 [https://bugs.python.org/issue?@action=redirect&bpo=20355]: -W command line options now have higher priority than the PYTHONWARNINGS environment variable. Patch by Arfrever.

bpo-21274 [https://bugs.python.org/issue?@action=redirect&bpo=21274]: Define PATH_MAX for GNU/Hurd in Python/pythonrun.c.

bpo-20904 [https://bugs.python.org/issue?@action=redirect&bpo=20904]: Support setting FPU precision on m68k.

bpo-21209 [https://bugs.python.org/issue?@action=redirect&bpo=21209]: Fix sending tuples to custom generator objects with the yield from syntax.

bpo-21193 [https://bugs.python.org/issue?@action=redirect&bpo=21193]: pow(a, b, c) now raises ValueError rather than TypeError when b is negative. Patch by Josh Rosenberg.

bpo-21176 [https://bugs.python.org/issue?@action=redirect&bpo=21176]: PEP 465: Add the ‘@’ operator for matrix multiplication.

bpo-21134 [https://bugs.python.org/issue?@action=redirect&bpo=21134]: Fix segfault when str is called on an uninitialized UnicodeEncodeError, UnicodeDecodeError, or UnicodeTranslateError object.

bpo-19537 [https://bugs.python.org/issue?@action=redirect&bpo=19537]: Fix PyUnicode_DATA() alignment under m68k. Patch by Andreas Schwab.

bpo-20929 [https://bugs.python.org/issue?@action=redirect&bpo=20929]: Add a type cast to avoid shifting a negative number.

bpo-20731 [https://bugs.python.org/issue?@action=redirect&bpo=20731]: Properly position in source code files even if they are opened in text mode. Patch by Serhiy Storchaka.

bpo-20637 [https://bugs.python.org/issue?@action=redirect&bpo=20637]: Key-sharing now also works for instance dictionaries of subclasses. Patch by Peter Ingebretson.

bpo-8297 [https://bugs.python.org/issue?@action=redirect&bpo=8297]: Attributes missing from modules now include the module name in the error text. Original patch by ysj.ray.

bpo-19995 [https://bugs.python.org/issue?@action=redirect&bpo=19995]: %c, %o, %x, and %X now raise TypeError on non-integer input.

bpo-19655 [https://bugs.python.org/issue?@action=redirect&bpo=19655]: The ASDL parser - used by the build process to generate code for managing the Python AST in C - was rewritten. The new parser is self contained and does not require to carry long the spark.py parser-generator library; spark.py was removed from the source base.

bpo-12546 [https://bugs.python.org/issue?@action=redirect&bpo=12546]: Allow \x00 to be used as a fill character when using str, int, float, and complex __format__ methods.

bpo-20480 [https://bugs.python.org/issue?@action=redirect&bpo=20480]: Add ipaddress.reverse_pointer. Patch by Leon Weber.

bpo-13598 [https://bugs.python.org/issue?@action=redirect&bpo=13598]: Modify string.Formatter to support auto-numbering of replacement fields. It now matches the behavior of str.format() in this regard. Patches by Phil Elson and Ramchandra Apte.

bpo-8931 [https://bugs.python.org/issue?@action=redirect&bpo=8931]: Make alternate formatting (‘#’) for type ‘c’ raise an exception. In versions prior to 3.5, ‘#’ with ‘c’ had no effect. Now specifying it is an error. Patch by Torsten Landschoff.

bpo-23165 [https://bugs.python.org/issue?@action=redirect&bpo=23165]: Perform overflow checks before allocating memory in the _Py_char2wchar function.

Library

bpo-23399 [https://bugs.python.org/issue?@action=redirect&bpo=23399]: pyvenv creates relative symlinks where possible.

bpo-20289 [https://bugs.python.org/issue?@action=redirect&bpo=20289]: cgi.FieldStorage() now supports the context management protocol.

bpo-13128 [https://bugs.python.org/issue?@action=redirect&bpo=13128]: Print response headers for CONNECT requests when debuglevel > 0. Patch by Demian Brecht.

bpo-15381 [https://bugs.python.org/issue?@action=redirect&bpo=15381]: Optimized io.BytesIO to make less allocations and copyings.

bpo-22818 [https://bugs.python.org/issue?@action=redirect&bpo=22818]: Splitting on a pattern that could match an empty string now raises a warning. Patterns that can only match empty strings are now rejected.

bpo-23099 [https://bugs.python.org/issue?@action=redirect&bpo=23099]: Closing io.BytesIO with exported buffer is rejected now to prevent corrupting exported buffer.

bpo-23326 [https://bugs.python.org/issue?@action=redirect&bpo=23326]: Removed __ne__ implementations. Since fixing default __ne__ implementation in bpo-21408 [https://bugs.python.org/issue?@action=redirect&bpo=21408] they are redundant.

bpo-23363 [https://bugs.python.org/issue?@action=redirect&bpo=23363]: Fix possible overflow in itertools.permutations.

bpo-23364 [https://bugs.python.org/issue?@action=redirect&bpo=23364]: Fix possible overflow in itertools.product.

bpo-23366 [https://bugs.python.org/issue?@action=redirect&bpo=23366]: Fixed possible integer overflow in itertools.combinations.

bpo-23369 [https://bugs.python.org/issue?@action=redirect&bpo=23369]: Fixed possible integer overflow in _json.encode_basestring_ascii.

bpo-23353 [https://bugs.python.org/issue?@action=redirect&bpo=23353]: Fix the exception handling of generators in PyEval_EvalFrameEx(). At entry, save or swap the exception state even if PyEval_EvalFrameEx() is called with throwflag=0. At exit, the exception state is now always restored or swapped, not only if why is WHY_YIELD or WHY_RETURN. Patch co-written with Antoine Pitrou.

bpo-14099 [https://bugs.python.org/issue?@action=redirect&bpo=14099]: Restored support of writing ZIP files to tellable but non-seekable streams.

bpo-14099 [https://bugs.python.org/issue?@action=redirect&bpo=14099]: Writing to ZipFile and reading multiple ZipExtFiles is threadsafe now.

bpo-19361 [https://bugs.python.org/issue?@action=redirect&bpo=19361]: JSON decoder now raises JSONDecodeError instead of ValueError.

bpo-18518 [https://bugs.python.org/issue?@action=redirect&bpo=18518]: timeit now rejects statements which can’t be compiled outside a function or a loop (e.g. “return” or “break”).

bpo-23094 [https://bugs.python.org/issue?@action=redirect&bpo=23094]: Fixed readline with frames in Python implementation of pickle.

bpo-23268 [https://bugs.python.org/issue?@action=redirect&bpo=23268]: Fixed bugs in the comparison of ipaddress classes.

bpo-21408 [https://bugs.python.org/issue?@action=redirect&bpo=21408]: Removed incorrect implementations of __ne__() which didn’t returned NotImplemented if __eq__() returned NotImplemented. The default __ne__() now works correctly.

bpo-19996 [https://bugs.python.org/issue?@action=redirect&bpo=19996]: email.feedparser.FeedParser now handles (malformed) headers with no key rather than assuming the body has started.

bpo-20188 [https://bugs.python.org/issue?@action=redirect&bpo=20188]: Support Application-Layer Protocol Negotiation (ALPN) in the ssl module.

bpo-23133 [https://bugs.python.org/issue?@action=redirect&bpo=23133]: Pickling of ipaddress objects now produces more compact and portable representation.

bpo-23248 [https://bugs.python.org/issue?@action=redirect&bpo=23248]: Update ssl error codes from latest OpenSSL git master.

bpo-23266 [https://bugs.python.org/issue?@action=redirect&bpo=23266]: Much faster implementation of ipaddress.collapse_addresses() when there are many non-consecutive addresses.

bpo-23098 [https://bugs.python.org/issue?@action=redirect&bpo=23098]: 64-bit dev_t is now supported in the os module.

bpo-21817 [https://bugs.python.org/issue?@action=redirect&bpo=21817]: When an exception is raised in a task submitted to a ProcessPoolExecutor, the remote traceback is now displayed in the parent process. Patch by Claudiu Popa.

bpo-15955 [https://bugs.python.org/issue?@action=redirect&bpo=15955]: Add an option to limit output size when decompressing LZMA data. Patch by Nikolaus Rath and Martin Panter.

bpo-23250 [https://bugs.python.org/issue?@action=redirect&bpo=23250]: In the http.cookies module, capitalize “HttpOnly” and “Secure” as they are written in the standard.

bpo-23063 [https://bugs.python.org/issue?@action=redirect&bpo=23063]: In the distutils’ check command, fix parsing of reST with code or code-block directives.

bpo-23209 [https://bugs.python.org/issue?@action=redirect&bpo=23209]: selectors.BaseSelector.get_key() now raises a RuntimeError if the selector is closed. And selectors.BaseSelector.close() now clears its internal reference to the selector mapping to break a reference cycle. Initial patch written by Martin Richard. (See also: bpo-23225 [https://bugs.python.org/issue?@action=redirect&bpo=23225])

bpo-17911 [https://bugs.python.org/issue?@action=redirect&bpo=17911]: Provide a way to seed the linecache for a PEP-302 module without actually loading the code.

bpo-17911 [https://bugs.python.org/issue?@action=redirect&bpo=17911]: Provide a new object API for traceback, including the ability to not lookup lines at all until the traceback is actually rendered, without any trace of the original objects being kept alive.

bpo-19777 [https://bugs.python.org/issue?@action=redirect&bpo=19777]: Provide a home() classmethod on Path objects. Contributed by Victor Salgado and Mayank Tripathi.

bpo-23206 [https://bugs.python.org/issue?@action=redirect&bpo=23206]: Make json.dumps(..., ensure_ascii=False) as fast as the default case of ensure_ascii=True. Patch by Naoki Inada.

bpo-23185 [https://bugs.python.org/issue?@action=redirect&bpo=23185]: Add math.inf and math.nan constants.

bpo-23186 [https://bugs.python.org/issue?@action=redirect&bpo=23186]: Add ssl.SSLObject.shared_ciphers() and ssl.SSLSocket.shared_ciphers() to fetch the client’s list ciphers sent at handshake.

bpo-23143 [https://bugs.python.org/issue?@action=redirect&bpo=23143]: Remove compatibility with OpenSSLs older than 0.9.8.

bpo-23132 [https://bugs.python.org/issue?@action=redirect&bpo=23132]: Improve performance and introspection support of comparison methods created by functool.total_ordering.

bpo-19776 [https://bugs.python.org/issue?@action=redirect&bpo=19776]: Add an expanduser() method on Path objects.

bpo-23112 [https://bugs.python.org/issue?@action=redirect&bpo=23112]: Fix SimpleHTTPServer to correctly carry the query string and fragment when it redirects to add a trailing slash.

bpo-21793 [https://bugs.python.org/issue?@action=redirect&bpo=21793]: Added http.HTTPStatus enums (i.e. HTTPStatus.OK, HTTPStatus.NOT_FOUND). Patch by Demian Brecht.

bpo-23093 [https://bugs.python.org/issue?@action=redirect&bpo=23093]: In the io, module allow more operations to work on detached streams.

bpo-23111 [https://bugs.python.org/issue?@action=redirect&bpo=23111]: In the ftplib, make ssl.PROTOCOL_SSLv23 the default protocol version.

bpo-22585 [https://bugs.python.org/issue?@action=redirect&bpo=22585]: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(), instead of reading /dev/urandom, to get pseudo-random bytes.

bpo-19104 [https://bugs.python.org/issue?@action=redirect&bpo=19104]: pprint now produces evaluable output for wrapped strings.

bpo-23071 [https://bugs.python.org/issue?@action=redirect&bpo=23071]: Added missing names to codecs.__all__. Patch by Martin Panter.

bpo-22783 [https://bugs.python.org/issue?@action=redirect&bpo=22783]: Pickling now uses the NEWOBJ opcode instead of the NEWOBJ_EX opcode if possible.

bpo-15513 [https://bugs.python.org/issue?@action=redirect&bpo=15513]: Added a __sizeof__ implementation for pickle classes.

bpo-19858 [https://bugs.python.org/issue?@action=redirect&bpo=19858]: pickletools.optimize() now aware of the MEMOIZE opcode, can produce more compact result and no longer produces invalid output if input data contains MEMOIZE opcodes together with PUT or BINPUT opcodes.

bpo-22095 [https://bugs.python.org/issue?@action=redirect&bpo=22095]: Fixed HTTPConnection.set_tunnel with default port. The port value in the host header was set to “None”. Patch by Demian Brecht.

bpo-23016 [https://bugs.python.org/issue?@action=redirect&bpo=23016]: A warning no longer produces an AttributeError when the program is run with pythonw.exe.

bpo-21775 [https://bugs.python.org/issue?@action=redirect&bpo=21775]: shutil.copytree(): fix crash when copying to VFAT. An exception handler assumed that OSError objects always have a ‘winerror’ attribute. That is not the case, so the exception handler itself raised AttributeError when run on Linux (and, presumably, any other non-Windows OS). Patch by Greg Ward.

bpo-1218234 [https://bugs.python.org/issue?@action=redirect&bpo=1218234]: Fix inspect.getsource() to load updated source of reloaded module. Initial patch by Berker Peksag.

bpo-21740 [https://bugs.python.org/issue?@action=redirect&bpo=21740]: Support wrapped callables in doctest. Patch by Claudiu Popa.

bpo-23009 [https://bugs.python.org/issue?@action=redirect&bpo=23009]: Make sure selectors.EpollSelector.select() works when no FD is registered.

bpo-22959 [https://bugs.python.org/issue?@action=redirect&bpo=22959]: In the constructor of http.client.HTTPSConnection, prefer the context’s check_hostname attribute over the check_hostname parameter.

bpo-22696 [https://bugs.python.org/issue?@action=redirect&bpo=22696]: Add function sys.is_finalizing() to know about interpreter shutdown.

bpo-16043 [https://bugs.python.org/issue?@action=redirect&bpo=16043]: Add a default limit for the amount of data xmlrpclib.gzip_decode will return. This resolves CVE 2013-1753 [https://www.cve.org/CVERecord?id=CVE-2013-1753].

bpo-14099 [https://bugs.python.org/issue?@action=redirect&bpo=14099]: ZipFile.open() no longer reopen the underlying file. Objects returned by ZipFile.open() can now operate independently of the ZipFile even if the ZipFile was created by passing in a file-like object as the first argument to the constructor.

bpo-22966 [https://bugs.python.org/issue?@action=redirect&bpo=22966]: Fix __pycache__ pyc file name clobber when pyc_compile is asked to compile a source file containing multiple dots in the source file name.

bpo-21971 [https://bugs.python.org/issue?@action=redirect&bpo=21971]: Update turtledemo doc and add module to the index.

bpo-21032 [https://bugs.python.org/issue?@action=redirect&bpo=21032]: Fixed socket leak if HTTPConnection.getresponse() fails. Original patch by Martin Panter.

bpo-22407 [https://bugs.python.org/issue?@action=redirect&bpo=22407]: Deprecated the use of re.LOCALE flag with str patterns or re.ASCII. It was newer worked.

bpo-22902 [https://bugs.python.org/issue?@action=redirect&bpo=22902]: The “ip” command is now used on Linux to determine MAC address in uuid.getnode(). Patch by Bruno Cauet.

bpo-22960 [https://bugs.python.org/issue?@action=redirect&bpo=22960]: Add a context argument to xmlrpclib.ServerProxy constructor.

bpo-22389 [https://bugs.python.org/issue?@action=redirect&bpo=22389]: Add contextlib.redirect_stderr().

bpo-21356 [https://bugs.python.org/issue?@action=redirect&bpo=21356]: Make ssl.RAND_egd() optional to support LibreSSL. The availability of the function is checked during the compilation. Patch written by Bernard Spil.

bpo-22915 [https://bugs.python.org/issue?@action=redirect&bpo=22915]: SAX parser now supports files opened with file descriptor or bytes path.

bpo-22609 [https://bugs.python.org/issue?@action=redirect&bpo=22609]: Constructors and update methods of mapping classes in the collections module now accept the self keyword argument.

bpo-22940 [https://bugs.python.org/issue?@action=redirect&bpo=22940]: Add readline.append_history_file.

bpo-19676 [https://bugs.python.org/issue?@action=redirect&bpo=19676]: Added the “namereplace” error handler.

bpo-22788 [https://bugs.python.org/issue?@action=redirect&bpo=22788]: Add context parameter to logging.handlers.HTTPHandler.

bpo-22921 [https://bugs.python.org/issue?@action=redirect&bpo=22921]: Allow SSLContext to take the hostname parameter even if OpenSSL doesn’t support SNI.

bpo-22894 [https://bugs.python.org/issue?@action=redirect&bpo=22894]: TestCase.subTest() would cause the test suite to be stopped when in failfast mode, even in the absence of failures.

bpo-22796 [https://bugs.python.org/issue?@action=redirect&bpo=22796]: HTTP cookie parsing is now stricter, in order to protect against potential injection attacks.

bpo-22370 [https://bugs.python.org/issue?@action=redirect&bpo=22370]: Windows detection in pathlib is now more robust.

bpo-22841 [https://bugs.python.org/issue?@action=redirect&bpo=22841]: Reject coroutines in asyncio add_signal_handler(). Patch by Ludovic.Gasc.

bpo-19494 [https://bugs.python.org/issue?@action=redirect&bpo=19494]: Added urllib.request.HTTPBasicPriorAuthHandler. Patch by Matej Cepl.

bpo-22578 [https://bugs.python.org/issue?@action=redirect&bpo=22578]: Added attributes to the re.error class.

bpo-22849 [https://bugs.python.org/issue?@action=redirect&bpo=22849]: Fix possible double free in the io.TextIOWrapper constructor.

bpo-12728 [https://bugs.python.org/issue?@action=redirect&bpo=12728]: Different Unicode characters having the same uppercase but different lowercase are now matched in case-insensitive regular expressions.

bpo-22821 [https://bugs.python.org/issue?@action=redirect&bpo=22821]: Fixed fcntl() with integer argument on 64-bit big-endian platforms.

bpo-21650 [https://bugs.python.org/issue?@action=redirect&bpo=21650]: Add an --sort-keys option to json.tool CLI.

bpo-22824 [https://bugs.python.org/issue?@action=redirect&bpo=22824]: Updated reprlib output format for sets to use set literals. Patch contributed by Berker Peksag.

bpo-22824 [https://bugs.python.org/issue?@action=redirect&bpo=22824]: Updated reprlib output format for arrays to display empty arrays without an unnecessary empty list. Suggested by Serhiy Storchaka.

bpo-22406 [https://bugs.python.org/issue?@action=redirect&bpo=22406]: Fixed the uu_codec codec incorrectly ported to 3.x. Based on patch by Martin Panter.

bpo-17293 [https://bugs.python.org/issue?@action=redirect&bpo=17293]: uuid.getnode() now determines MAC address on AIX using netstat. Based on patch by Aivars Kalvāns.

bpo-22769 [https://bugs.python.org/issue?@action=redirect&bpo=22769]: Fixed ttk.Treeview.tag_has() when called without arguments.

bpo-22417 [https://bugs.python.org/issue?@action=redirect&bpo=22417]: Verify certificates by default in httplib (PEP 476).

bpo-22775 [https://bugs.python.org/issue?@action=redirect&bpo=22775]: Fixed unpickling of http.cookies.SimpleCookie with protocol 2 and above. Patch by Tim Graham.

bpo-22776 [https://bugs.python.org/issue?@action=redirect&bpo=22776]: Brought excluded code into the scope of a try block in SysLogHandler.emit().

bpo-22665 [https://bugs.python.org/issue?@action=redirect&bpo=22665]: Add missing get_terminal_size and SameFileError to shutil.__all__.

bpo-6623 [https://bugs.python.org/issue?@action=redirect&bpo=6623]: Remove deprecated Netrc class in the ftplib module. Patch by Matt Chaput.

bpo-17381 [https://bugs.python.org/issue?@action=redirect&bpo=17381]: Fixed handling of case-insensitive ranges in regular expressions.

bpo-22410 [https://bugs.python.org/issue?@action=redirect&bpo=22410]: Module level functions in the re module now cache compiled locale-dependent regular expressions taking into account the locale.

bpo-22759 [https://bugs.python.org/issue?@action=redirect&bpo=22759]: Query methods on pathlib.Path() (exists(), is_dir(), etc.) now return False when the underlying stat call raises NotADirectoryError.

bpo-8876 [https://bugs.python.org/issue?@action=redirect&bpo=8876]: distutils now falls back to copying files when hard linking doesn’t work. This allows use with special filesystems such as VirtualBox shared folders.

bpo-22217 [https://bugs.python.org/issue?@action=redirect&bpo=22217]: Implemented reprs of classes in the zipfile module.

bpo-22457 [https://bugs.python.org/issue?@action=redirect&bpo=22457]: Honour load_tests in the start_dir of discovery.

bpo-18216 [https://bugs.python.org/issue?@action=redirect&bpo=18216]: gettext now raises an error when a .mo file has an unsupported major version number. Patch by Aaron Hill.

bpo-13918 [https://bugs.python.org/issue?@action=redirect&bpo=13918]: Provide a locale.delocalize() function which can remove locale-specific number formatting from a string representing a number, without then converting it to a specific type. Patch by Cédric Krier.

bpo-22676 [https://bugs.python.org/issue?@action=redirect&bpo=22676]: Make the pickling of global objects which don’t have a __module__ attribute less slow.

bpo-18853 [https://bugs.python.org/issue?@action=redirect&bpo=18853]: Fixed ResourceWarning in shlex.__nain__.

bpo-9351 [https://bugs.python.org/issue?@action=redirect&bpo=9351]: Defaults set with set_defaults on an argparse subparser are no longer ignored when also set on the parent parser.

bpo-7559 [https://bugs.python.org/issue?@action=redirect&bpo=7559]: unittest test loading ImportErrors are reported as import errors with their import exception rather than as attribute errors after the import has already failed.

bpo-19746 [https://bugs.python.org/issue?@action=redirect&bpo=19746]: Make it possible to examine the errors from unittest discovery without executing the test suite. The new errors attribute on TestLoader exposes these non-fatal errors encountered during discovery.

bpo-21991 [https://bugs.python.org/issue?@action=redirect&bpo=21991]: Make email.headerregistry’s header ‘params’ attributes be read-only (MappingProxyType). Previously the dictionary was modifiable but a new one was created on each access of the attribute.

bpo-22638 [https://bugs.python.org/issue?@action=redirect&bpo=22638]: SSLv3 is now disabled throughout the standard library. It can still be enabled by instantiating a SSLContext manually.

bpo-22641 [https://bugs.python.org/issue?@action=redirect&bpo=22641]: In asyncio, the default SSL context for client connections is now created using ssl.create_default_context(), for stronger security.

bpo-17401 [https://bugs.python.org/issue?@action=redirect&bpo=17401]: Include closefd in io.FileIO repr.

bpo-21338 [https://bugs.python.org/issue?@action=redirect&bpo=21338]: Add silent mode for compileall. quiet parameters of compile_{dir, file, path} functions now have a multilevel value. Also, -q option of the CLI now have a multilevel value. Patch by Thomas Kluyver.

bpo-20152 [https://bugs.python.org/issue?@action=redirect&bpo=20152]: Convert the array and cmath modules to Argument Clinic.

bpo-18643 [https://bugs.python.org/issue?@action=redirect&bpo=18643]: Add socket.socketpair() on Windows.

bpo-22435 [https://bugs.python.org/issue?@action=redirect&bpo=22435]: Fix a file descriptor leak when socketserver bind fails.

bpo-13096 [https://bugs.python.org/issue?@action=redirect&bpo=13096]: Fixed segfault in CTypes POINTER handling of large values.

bpo-11694 [https://bugs.python.org/issue?@action=redirect&bpo=11694]: Raise ConversionError in xdrlib as documented. Patch by Filip Gruszczyński and Claudiu Popa.

bpo-19380 [https://bugs.python.org/issue?@action=redirect&bpo=19380]: Optimized parsing of regular expressions.

bpo-1519638 [https://bugs.python.org/issue?@action=redirect&bpo=1519638]: Now unmatched groups are replaced with empty strings in re.sub() and re.subn().

bpo-18615 [https://bugs.python.org/issue?@action=redirect&bpo=18615]: sndhdr.what/whathdr now return a namedtuple.

bpo-22462 [https://bugs.python.org/issue?@action=redirect&bpo=22462]: Fix pyexpat’s creation of a dummy frame to make it appear in exception tracebacks.

bpo-21965 [https://bugs.python.org/issue?@action=redirect&bpo=21965]: Add support for in-memory SSL to the ssl module. Patch by Geert Jansen.

bpo-21173 [https://bugs.python.org/issue?@action=redirect&bpo=21173]: Fix len() on a WeakKeyDictionary when .clear() was called with an iterator alive.

bpo-11866 [https://bugs.python.org/issue?@action=redirect&bpo=11866]: Eliminated race condition in the computation of names for new threads.

bpo-21905 [https://bugs.python.org/issue?@action=redirect&bpo=21905]: Avoid RuntimeError in pickle.whichmodule() when sys.modules is mutated while iterating. Patch by Olivier Grisel.

bpo-11271 [https://bugs.python.org/issue?@action=redirect&bpo=11271]: concurrent.futures.Executor.map() now takes a chunksize argument to allow batching of tasks in child processes and improve performance of ProcessPoolExecutor. Patch by Dan O’Reilly.

bpo-21883 [https://bugs.python.org/issue?@action=redirect&bpo=21883]: os.path.join() and os.path.relpath() now raise a TypeError with more helpful error message for unsupported or mismatched types of arguments.

bpo-22219 [https://bugs.python.org/issue?@action=redirect&bpo=22219]: The zipfile module CLI now adds entries for directories (including empty directories) in ZIP file.

bpo-22449 [https://bugs.python.org/issue?@action=redirect&bpo=22449]: In the ssl.SSLContext.load_default_certs, consult the environmental variables SSL_CERT_DIR and SSL_CERT_FILE on Windows.

bpo-22508 [https://bugs.python.org/issue?@action=redirect&bpo=22508]: The email.__version__ variable has been removed; the email code is no longer shipped separately from the stdlib, and __version__ hasn’t been updated in several releases.

bpo-20076 [https://bugs.python.org/issue?@action=redirect&bpo=20076]: Added non derived UTF-8 aliases to locale aliases table.

bpo-20079 [https://bugs.python.org/issue?@action=redirect&bpo=20079]: Added locales supported in glibc 2.18 to locale alias table.

bpo-20218 [https://bugs.python.org/issue?@action=redirect&bpo=20218]: Added convenience methods read_text/write_text and read_bytes/ write_bytes to pathlib.Path objects.

bpo-22396 [https://bugs.python.org/issue?@action=redirect&bpo=22396]: On 32-bit AIX platform, don’t expose os.posix_fadvise() nor os.posix_fallocate() because their prototypes in system headers are wrong.

bpo-22517 [https://bugs.python.org/issue?@action=redirect&bpo=22517]: When an io.BufferedRWPair object is deallocated, clear its weakrefs.

bpo-22437 [https://bugs.python.org/issue?@action=redirect&bpo=22437]: Number of capturing groups in regular expression is no longer limited by 100.

bpo-17442 [https://bugs.python.org/issue?@action=redirect&bpo=17442]: InteractiveInterpreter now displays the full chained traceback in its showtraceback method, to match the built in interactive interpreter.

bpo-23392 [https://bugs.python.org/issue?@action=redirect&bpo=23392]: Added tests for marshal C API that works with FILE*.

bpo-10510 [https://bugs.python.org/issue?@action=redirect&bpo=10510]: distutils register and upload methods now use HTML standards compliant CRLF line endings.

bpo-9850 [https://bugs.python.org/issue?@action=redirect&bpo=9850]: Fixed macpath.join() for empty first component. Patch by Oleg Oshmyan.

bpo-5309 [https://bugs.python.org/issue?@action=redirect&bpo=5309]: distutils’ build and build_ext commands now accept a -j option to enable parallel building of extension modules.

bpo-22448 [https://bugs.python.org/issue?@action=redirect&bpo=22448]: Improve canceled timer handles cleanup to prevent unbound memory usage. Patch by Joshua Moore-Oliva.

bpo-22427 [https://bugs.python.org/issue?@action=redirect&bpo=22427]: TemporaryDirectory no longer attempts to clean up twice when used in the with statement in generator.

bpo-22362 [https://bugs.python.org/issue?@action=redirect&bpo=22362]: Forbidden ambiguous octal escapes out of range 0-0o377 in regular expressions.

bpo-20912 [https://bugs.python.org/issue?@action=redirect&bpo=20912]: Now directories added to ZIP file have correct Unix and MS-DOS directory attributes.

bpo-21866 [https://bugs.python.org/issue?@action=redirect&bpo=21866]: ZipFile.close() no longer writes ZIP64 central directory records if allowZip64 is false.

bpo-22278 [https://bugs.python.org/issue?@action=redirect&bpo=22278]: Fix urljoin problem with relative urls, a regression observed after changes to issue22118 were submitted.

bpo-22415 [https://bugs.python.org/issue?@action=redirect&bpo=22415]: Fixed debugging output of the GROUPREF_EXISTS opcode in the re module. Removed trailing spaces in debugging output.

bpo-22423 [https://bugs.python.org/issue?@action=redirect&bpo=22423]: Unhandled exception in thread no longer causes unhandled AttributeError when sys.stderr is None.

bpo-21332 [https://bugs.python.org/issue?@action=redirect&bpo=21332]: Ensure that bufsize=1 in subprocess.Popen() selects line buffering, rather than block buffering. Patch by Akira Li.

bpo-21091 [https://bugs.python.org/issue?@action=redirect&bpo=21091]: Fix API bug: email.message.EmailMessage.is_attachment is now a method.

bpo-21079 [https://bugs.python.org/issue?@action=redirect&bpo=21079]: Fix email.message.EmailMessage.is_attachment to return the correct result when the header has parameters as well as a value.

bpo-22247 [https://bugs.python.org/issue?@action=redirect&bpo=22247]: Add NNTPError to nntplib.__all__.

bpo-22366 [https://bugs.python.org/issue?@action=redirect&bpo=22366]: urllib.request.urlopen will accept a context object (SSLContext) as an argument which will then be used for HTTPS connection. Patch by Alex Gaynor.

bpo-4180 [https://bugs.python.org/issue?@action=redirect&bpo=4180]: The warnings registries are now reset when the filters are modified.

bpo-22419 [https://bugs.python.org/issue?@action=redirect&bpo=22419]: Limit the length of incoming HTTP request in wsgiref server to 65536 bytes and send a 414 error code for higher lengths. Patch contributed by Devin Cook.

Lax cookie parsing in http.cookies could be a security issue when combined with non-standard cookie handling in some web browsers. Reported by Sergey Bobrov.

bpo-20537 [https://bugs.python.org/issue?@action=redirect&bpo=20537]: logging methods now accept an exception instance as well as a Boolean value or exception tuple. Thanks to Yury Selivanov for the patch.

bpo-22384 [https://bugs.python.org/issue?@action=redirect&bpo=22384]: An exception in Tkinter callback no longer crashes the program when it is run with pythonw.exe.

bpo-22168 [https://bugs.python.org/issue?@action=redirect&bpo=22168]: Prevent turtle AttributeError with non-default Canvas on OS X.

bpo-21147 [https://bugs.python.org/issue?@action=redirect&bpo=21147]: sqlite3 now raises an exception if the request contains a null character instead of truncating it. Based on patch by Victor Stinner.

bpo-13968 [https://bugs.python.org/issue?@action=redirect&bpo=13968]: The glob module now supports recursive search in subdirectories using the ** pattern.

bpo-21951 [https://bugs.python.org/issue?@action=redirect&bpo=21951]: Fixed a crash in Tkinter on AIX when called Tcl command with empty string or tuple argument.

bpo-21951 [https://bugs.python.org/issue?@action=redirect&bpo=21951]: Tkinter now most likely raises MemoryError instead of crash if the memory allocation fails.

bpo-22338 [https://bugs.python.org/issue?@action=redirect&bpo=22338]: Fix a crash in the json module on memory allocation failure.

bpo-12410 [https://bugs.python.org/issue?@action=redirect&bpo=12410]: imaplib.IMAP4 now supports the context management protocol. Original patch by Tarek Ziadé.

bpo-21270 [https://bugs.python.org/issue?@action=redirect&bpo=21270]: We now override tuple methods in mock.call objects so that they can be used as normal call attributes.

bpo-16662 [https://bugs.python.org/issue?@action=redirect&bpo=16662]: load_tests() is now unconditionally run when it is present in a package’s __init__.py. TestLoader.loadTestsFromModule() still accepts use_load_tests, but it is deprecated and ignored. A new keyword-only attribute pattern is added and documented. Patch given by Robert Collins, tweaked by Barry Warsaw.

bpo-22226 [https://bugs.python.org/issue?@action=redirect&bpo=22226]: First letter no longer is stripped from the “status” key in the result of Treeview.heading().

bpo-19524 [https://bugs.python.org/issue?@action=redirect&bpo=19524]: Fixed resource leak in the HTTP connection when an invalid response is received. Patch by Martin Panter.

bpo-20421 [https://bugs.python.org/issue?@action=redirect&bpo=20421]: Add a .version() method to SSL sockets exposing the actual protocol version in use.

bpo-19546 [https://bugs.python.org/issue?@action=redirect&bpo=19546]: configparser exceptions no longer expose implementation details. Chained KeyErrors are removed, which leads to cleaner tracebacks. Patch by Claudiu Popa.

bpo-22051 [https://bugs.python.org/issue?@action=redirect&bpo=22051]: turtledemo no longer reloads examples to re-run them. Initialization of variables and gui setup should be done in main(), which is called each time a demo is run, but not on import.

bpo-21933 [https://bugs.python.org/issue?@action=redirect&bpo=21933]: Turtledemo users can change the code font size with a menu selection or control(command) ‘-’ or ‘+’ or control-mousewheel. Original patch by Lita Cho.

bpo-21597 [https://bugs.python.org/issue?@action=redirect&bpo=21597]: The separator between the turtledemo text pane and the drawing canvas can now be grabbed and dragged with a mouse. The code text pane can be widened to easily view or copy the full width of the text. The canvas can be widened on small screens. Original patches by Jan Kanis and Lita Cho.

bpo-18132 [https://bugs.python.org/issue?@action=redirect&bpo=18132]: Turtledemo buttons no longer disappear when the window is shrunk. Original patches by Jan Kanis and Lita Cho.

bpo-22043 [https://bugs.python.org/issue?@action=redirect&bpo=22043]: time.monotonic() is now always available. threading.Lock.acquire(), threading.RLock.acquire() and socket operations now use a monotonic clock, instead of the system clock, when a timeout is used.

bpo-21527 [https://bugs.python.org/issue?@action=redirect&bpo=21527]: Add a default number of workers to ThreadPoolExecutor equal to 5 times the number of CPUs. Patch by Claudiu Popa.

bpo-22216 [https://bugs.python.org/issue?@action=redirect&bpo=22216]: smtplib now resets its state more completely after a quit. The most obvious consequence of the previous behavior was a STARTTLS failure during a connect/starttls/quit/connect/starttls sequence.

bpo-22098 [https://bugs.python.org/issue?@action=redirect&bpo=22098]: ctypes’ BigEndianStructure and LittleEndianStructure now define an empty __slots__ so that subclasses don’t always get an instance dict. Patch by Claudiu Popa.

bpo-22185 [https://bugs.python.org/issue?@action=redirect&bpo=22185]: Fix an occasional RuntimeError in threading.Condition.wait() caused by mutation of the waiters queue without holding the lock. Patch by Doug Zongker.

bpo-22287 [https://bugs.python.org/issue?@action=redirect&bpo=22287]: On UNIX, _PyTime_gettimeofday() now uses clock_gettime(CLOCK_REALTIME) if available. As a side effect, Python now depends on the librt library on Solaris and on Linux (only with glibc older than 2.17).

bpo-22182 [https://bugs.python.org/issue?@action=redirect&bpo=22182]: Use e.args to unpack exceptions correctly in distutils.file_util.move_file. Patch by Claudiu Popa.

The webbrowser module now uses subprocess’s start_new_session=True rather than a potentially risky preexec_fn=os.setsid call.

bpo-22042 [https://bugs.python.org/issue?@action=redirect&bpo=22042]: signal.set_wakeup_fd(fd) now raises an exception if the file descriptor is in blocking mode.

bpo-16808 [https://bugs.python.org/issue?@action=redirect&bpo=16808]: inspect.stack() now returns a named tuple instead of a tuple. Patch by Daniel Shahaf.

bpo-22236 [https://bugs.python.org/issue?@action=redirect&bpo=22236]: Fixed Tkinter images copying operations in NoDefaultRoot mode.

bpo-2527 [https://bugs.python.org/issue?@action=redirect&bpo=2527]: Add a globals argument to timeit functions, in order to override the globals namespace in which the timed code is executed. Patch by Ben Roberts.

bpo-22118 [https://bugs.python.org/issue?@action=redirect&bpo=22118]: Switch urllib.parse to use RFC 3986 semantics for the resolution of relative URLs, rather than RFCs 1808 and 2396. Patch by Demian Brecht.

bpo-21549 [https://bugs.python.org/issue?@action=redirect&bpo=21549]: Added the “members” parameter to TarFile.list().

bpo-19628 [https://bugs.python.org/issue?@action=redirect&bpo=19628]: Allow compileall recursion depth to be specified with a -r option.

bpo-15696 [https://bugs.python.org/issue?@action=redirect&bpo=15696]: Add a __sizeof__ implementation for mmap objects on Windows.

bpo-22068 [https://bugs.python.org/issue?@action=redirect&bpo=22068]: Avoided reference loops with Variables and Fonts in Tkinter.

bpo-22165 [https://bugs.python.org/issue?@action=redirect&bpo=22165]: SimpleHTTPRequestHandler now supports undecodable file names.

bpo-15381 [https://bugs.python.org/issue?@action=redirect&bpo=15381]: Optimized line reading in io.BytesIO.

bpo-8797 [https://bugs.python.org/issue?@action=redirect&bpo=8797]: Raise HTTPError on failed Basic Authentication immediately. Initial patch by Sam Bull.

bpo-20729 [https://bugs.python.org/issue?@action=redirect&bpo=20729]: Restored the use of lazy iterkeys()/itervalues()/iteritems() in the mailbox module.

bpo-21448 [https://bugs.python.org/issue?@action=redirect&bpo=21448]: Changed FeedParser feed() to avoid O(n²) behavior when parsing long line. Original patch by Raymond Hettinger.

bpo-22184 [https://bugs.python.org/issue?@action=redirect&bpo=22184]: The functools LRU Cache decorator factory now gives an earlier and clearer error message when the user forgets the required parameters.

bpo-17923 [https://bugs.python.org/issue?@action=redirect&bpo=17923]: glob() patterns ending with a slash no longer match non-dirs on AIX. Based on patch by Delhallt.

bpo-21725 [https://bugs.python.org/issue?@action=redirect&bpo=21725]: Added support for RFC 6531 (SMTPUTF8) in smtpd.

bpo-22176 [https://bugs.python.org/issue?@action=redirect&bpo=22176]: Update the ctypes module’s libffi to v3.1. This release adds support for the Linux AArch64 and POWERPC ELF ABIv2 little endian architectures.

bpo-5411 [https://bugs.python.org/issue?@action=redirect&bpo=5411]: Added support for the “xztar” format in the shutil module.

bpo-21121 [https://bugs.python.org/issue?@action=redirect&bpo=21121]: Don’t force 3rd party C extensions to be built with -Werror=declaration-after-statement.

bpo-21975 [https://bugs.python.org/issue?@action=redirect&bpo=21975]: Fixed crash when using uninitialized sqlite3.Row (in particular when unpickling pickled sqlite3.Row). sqlite3.Row is now initialized in the __new__() method.

bpo-20170 [https://bugs.python.org/issue?@action=redirect&bpo=20170]: Convert posixmodule to use Argument Clinic.

bpo-21539 [https://bugs.python.org/issue?@action=redirect&bpo=21539]: Add an exists_ok argument to Pathlib.mkdir() to mimic mkdir -p and os.makedirs() functionality. When true, ignore FileExistsErrors. Patch by Berker Peksag.

bpo-22127 [https://bugs.python.org/issue?@action=redirect&bpo=22127]: Bypass IDNA for pure-ASCII host names in the socket module (in particular for numeric IPs).

bpo-21047 [https://bugs.python.org/issue?@action=redirect&bpo=21047]: set the default value for the convert_charrefs argument of HTMLParser to True. Patch by Berker Peksag.

Add an __all__ to html.entities.

bpo-15114 [https://bugs.python.org/issue?@action=redirect&bpo=15114]: the strict mode and argument of HTMLParser, HTMLParser.error, and the HTMLParserError exception have been removed.

bpo-22085 [https://bugs.python.org/issue?@action=redirect&bpo=22085]: Dropped support of Tk 8.3 in Tkinter.

bpo-21580 [https://bugs.python.org/issue?@action=redirect&bpo=21580]: Now Tkinter correctly handles bytes arguments passed to Tk. In particular this allows initializing images from binary data.

bpo-22003 [https://bugs.python.org/issue?@action=redirect&bpo=22003]: When initialized from a bytes object, io.BytesIO() now defers making a copy until it is mutated, improving performance and memory use on some use cases. Patch by David Wilson.

bpo-22018 [https://bugs.python.org/issue?@action=redirect&bpo=22018]: On Windows, signal.set_wakeup_fd() now also supports sockets. A side effect is that Python depends to the WinSock library.

bpo-22054 [https://bugs.python.org/issue?@action=redirect&bpo=22054]: Add os.get_blocking() and os.set_blocking() functions to get and set the blocking mode of a file descriptor (False if the O_NONBLOCK flag is set, True otherwise). These functions are not available on Windows.

bpo-17172 [https://bugs.python.org/issue?@action=redirect&bpo=17172]: Make turtledemo start as active on OS X even when run with subprocess. Patch by Lita Cho.

bpo-21704 [https://bugs.python.org/issue?@action=redirect&bpo=21704]: Fix build error for _multiprocessing when semaphores are not available. Patch by Arfrever Frehtes Taifersar Arahesis.

bpo-20173 [https://bugs.python.org/issue?@action=redirect&bpo=20173]: Convert sha1, sha256, sha512 and md5 to ArgumentClinic. Patch by Vajrasky Kok.

Fix repr(_socket.socket) on Windows 64-bit: don’t fail with OverflowError on closed socket. repr(socket.socket) already works fine.

bpo-22033 [https://bugs.python.org/issue?@action=redirect&bpo=22033]: Reprs of most Python implemented classes now contain actual class name instead of hardcoded one.

bpo-21947 [https://bugs.python.org/issue?@action=redirect&bpo=21947]: The dis module can now disassemble generator-iterator objects based on their gi_code attribute. Patch by Clement Rouault.

bpo-16133 [https://bugs.python.org/issue?@action=redirect&bpo=16133]: The asynchat.async_chat.handle_read() method now ignores BlockingIOError exceptions.

bpo-22044 [https://bugs.python.org/issue?@action=redirect&bpo=22044]: Fixed premature DECREF in call_tzinfo_method. Patch by Tom Flanagan.

bpo-19884 [https://bugs.python.org/issue?@action=redirect&bpo=19884]: readline: Disable the meta modifier key if stdout is not a terminal to not write the ANSI sequence "\033[1034h" into stdout. This sequence is used on some terminal (ex: TERM=xterm-256color”) to enable support of 8 bit characters.

bpo-4350 [https://bugs.python.org/issue?@action=redirect&bpo=4350]: Removed a number of out-of-dated and non-working for a long time Tkinter methods.

bpo-6167 [https://bugs.python.org/issue?@action=redirect&bpo=6167]: Scrollbar.activate() now returns the name of active element if the argument is not specified. Scrollbar.set() now always accepts only 2 arguments.

bpo-15275 [https://bugs.python.org/issue?@action=redirect&bpo=15275]: Clean up and speed up the ntpath module.

bpo-21888 [https://bugs.python.org/issue?@action=redirect&bpo=21888]: plistlib’s load() and loads() now work if the fmt parameter is specified.

bpo-22032 [https://bugs.python.org/issue?@action=redirect&bpo=22032]: __qualname__ instead of __name__ is now always used to format fully qualified class names of Python implemented classes.

bpo-22031 [https://bugs.python.org/issue?@action=redirect&bpo=22031]: Reprs now always use hexadecimal format with the “0x” prefix when contain an id in form “ at 0x…”.

bpo-22018 [https://bugs.python.org/issue?@action=redirect&bpo=22018]: signal.set_wakeup_fd() now raises an OSError instead of a ValueError on fstat() failure.

bpo-21044 [https://bugs.python.org/issue?@action=redirect&bpo=21044]: tarfile.open() now handles fileobj with an integer ‘name’ attribute. Based on patch by Antoine Pietri.

bpo-21966 [https://bugs.python.org/issue?@action=redirect&bpo=21966]: Respect -q command-line option when code module is ran.

bpo-19076 [https://bugs.python.org/issue?@action=redirect&bpo=19076]: Don’t pass the redundant ‘file’ argument to self.error().

bpo-16382 [https://bugs.python.org/issue?@action=redirect&bpo=16382]: Improve exception message of warnings.warn() for bad category. Initial patch by Phil Elson.

bpo-21932 [https://bugs.python.org/issue?@action=redirect&bpo=21932]: os.read() now uses a Py_ssize_t() type instead of int for the size to support reading more than 2 GB at once. On Windows, the size is truncated to INT_MAX. As any call to os.read(), the OS may read less bytes than the number of requested bytes.

bpo-21942 [https://bugs.python.org/issue?@action=redirect&bpo=21942]: Fixed source file viewing in pydoc’s server mode on Windows.

bpo-11259 [https://bugs.python.org/issue?@action=redirect&bpo=11259]: asynchat.async_chat().set_terminator() now raises a ValueError if the number of received bytes is negative.

bpo-12523 [https://bugs.python.org/issue?@action=redirect&bpo=12523]: asynchat.async_chat.push() now raises a TypeError if it doesn’t get a bytes string

bpo-21707 [https://bugs.python.org/issue?@action=redirect&bpo=21707]: Add missing kwonlyargcount argument to ModuleFinder.replace_paths_in_code().

bpo-20639 [https://bugs.python.org/issue?@action=redirect&bpo=20639]: calling Path.with_suffix(‘’) allows removing the suffix again. Patch by July Tikhonov.

bpo-21714 [https://bugs.python.org/issue?@action=redirect&bpo=21714]: Disallow the construction of invalid paths using Path.with_name(). Original patch by Antony Lee.

bpo-15014 [https://bugs.python.org/issue?@action=redirect&bpo=15014]: Added ‘auth’ method to smtplib to make implementing auth mechanisms simpler, and used it internally in the login method.

bpo-21151 [https://bugs.python.org/issue?@action=redirect&bpo=21151]: Fixed a segfault in the winreg module when None is passed as a REG_BINARY value to SetValueEx. Patch by John Ehresman.

bpo-21090 [https://bugs.python.org/issue?@action=redirect&bpo=21090]: io.FileIO.readall() does not ignore I/O errors anymore. Before, it ignored I/O errors if at least the first C call read() succeed.

bpo-5800 [https://bugs.python.org/issue?@action=redirect&bpo=5800]: headers parameter of wsgiref.headers.Headers is now optional. Initial patch by Pablo Torres Navarrete and SilentGhost.

bpo-21781 [https://bugs.python.org/issue?@action=redirect&bpo=21781]: ssl.RAND_add() now supports strings longer than 2 GB.

bpo-21679 [https://bugs.python.org/issue?@action=redirect&bpo=21679]: Prevent extraneous fstat() calls during open(). Patch by Bohuslav Kabrda.

bpo-21863 [https://bugs.python.org/issue?@action=redirect&bpo=21863]: cProfile now displays the module name of C extension functions, in addition to their own name.

bpo-11453 [https://bugs.python.org/issue?@action=redirect&bpo=11453]: asyncore: emit a ResourceWarning when an unclosed file_wrapper object is destroyed. The destructor now closes the file if needed. The close() method can now be called twice: the second call does nothing.

bpo-21858 [https://bugs.python.org/issue?@action=redirect&bpo=21858]: Better handling of Python exceptions in the sqlite3 module.

bpo-21476 [https://bugs.python.org/issue?@action=redirect&bpo=21476]: Make sure the email.parser.BytesParser TextIOWrapper is discarded after parsing, so the input file isn’t unexpectedly closed.

bpo-20295 [https://bugs.python.org/issue?@action=redirect&bpo=20295]: imghdr now recognizes OpenEXR format images.

bpo-21729 [https://bugs.python.org/issue?@action=redirect&bpo=21729]: Used the “with” statement in the dbm.dumb module to ensure files closing. Patch by Claudiu Popa.

bpo-21491 [https://bugs.python.org/issue?@action=redirect&bpo=21491]: socketserver: Fix a race condition in child processes reaping.

bpo-21719 [https://bugs.python.org/issue?@action=redirect&bpo=21719]: Added the st_file_attributes field to os.stat_result on Windows.

bpo-21832 [https://bugs.python.org/issue?@action=redirect&bpo=21832]: Require named tuple inputs to be exact strings.

bpo-21722 [https://bugs.python.org/issue?@action=redirect&bpo=21722]: The distutils “upload” command now exits with a non-zero return code when uploading fails. Patch by Martin Dengler.

bpo-21723 [https://bugs.python.org/issue?@action=redirect&bpo=21723]: asyncio.Queue: support any type of number (ex: float) for the maximum size. Patch written by Vajrasky Kok.

bpo-21711 [https://bugs.python.org/issue?@action=redirect&bpo=21711]: support for “site-python” directories has now been removed from the site module (it was deprecated in 3.4).

bpo-17552 [https://bugs.python.org/issue?@action=redirect&bpo=17552]: new socket.sendfile() method allowing a file to be sent over a socket by using high-performance os.sendfile() on UNIX. Patch by Giampaolo Rodola’.

bpo-18039 [https://bugs.python.org/issue?@action=redirect&bpo=18039]: dbm.dump.open() now always creates a new database when the flag has the value ‘n’. Patch by Claudiu Popa.

bpo-21326 [https://bugs.python.org/issue?@action=redirect&bpo=21326]: Add a new is_closed() method to asyncio.BaseEventLoop. run_forever() and run_until_complete() methods of asyncio.BaseEventLoop now raise an exception if the event loop was closed.

bpo-21766 [https://bugs.python.org/issue?@action=redirect&bpo=21766]: Prevent a security hole in CGIHTTPServer by URL unquoting paths before checking for a CGI script at that path.

bpo-21310 [https://bugs.python.org/issue?@action=redirect&bpo=21310]: Fixed possible resource leak in failed open().

bpo-21256 [https://bugs.python.org/issue?@action=redirect&bpo=21256]: Printout of keyword args should be in deterministic order in a mock function call. This will help to write better doctests.

bpo-21677 [https://bugs.python.org/issue?@action=redirect&bpo=21677]: Fixed chaining nonnormalized exceptions in io close() methods.

bpo-11709 [https://bugs.python.org/issue?@action=redirect&bpo=11709]: Fix the pydoc.help function to not fail when sys.stdin is not a valid file.

bpo-21515 [https://bugs.python.org/issue?@action=redirect&bpo=21515]: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available.

bpo-13223 [https://bugs.python.org/issue?@action=redirect&bpo=13223]: Fix pydoc.writedoc so that the HTML documentation for methods that use ‘self’ in the example code is generated correctly.

bpo-21463 [https://bugs.python.org/issue?@action=redirect&bpo=21463]: In urllib.request, fix pruning of the FTP cache.

bpo-21618 [https://bugs.python.org/issue?@action=redirect&bpo=21618]: The subprocess module could fail to close open fds that were inherited by the calling process and already higher than POSIX resource limits would otherwise allow. On systems with a functioning /proc/self/fd or /dev/fd interface the max is now ignored and all fds are closed.

bpo-20383 [https://bugs.python.org/issue?@action=redirect&bpo=20383]: Introduce importlib.util.module_from_spec() as the preferred way to create a new module.

bpo-21552 [https://bugs.python.org/issue?@action=redirect&bpo=21552]: Fixed possible integer overflow of too long string lengths in the tkinter module on 64-bit platforms.

bpo-14315 [https://bugs.python.org/issue?@action=redirect&bpo=14315]: The zipfile module now ignores extra fields in the central directory that are too short to be parsed instead of letting a struct.unpack error bubble up as this “bad data” appears in many real world zip files in the wild and is ignored by other zip tools.

bpo-13742 [https://bugs.python.org/issue?@action=redirect&bpo=13742]: Added “key” and “reverse” parameters to heapq.merge(). (First draft of patch contributed by Simon Sapin.)

bpo-21402 [https://bugs.python.org/issue?@action=redirect&bpo=21402]: tkinter.ttk now works when default root window is not set.

bpo-3015 [https://bugs.python.org/issue?@action=redirect&bpo=3015]: _tkinter.create() now creates tkapp object with wantobjects=1 by default.

bpo-10203 [https://bugs.python.org/issue?@action=redirect&bpo=10203]: sqlite3.Row now truly supports sequence protocol. In particular it supports reverse() and negative indices. Original patch by Claudiu Popa.

bpo-18807 [https://bugs.python.org/issue?@action=redirect&bpo=18807]: If copying (no symlinks) specified for a venv, then the python interpreter aliases (python, python3) are now created by copying rather than symlinking.

bpo-20197 [https://bugs.python.org/issue?@action=redirect&bpo=20197]: Added support for the WebP image type in the imghdr module. Patch by Fabrice Aneche and Claudiu Popa.

bpo-21513 [https://bugs.python.org/issue?@action=redirect&bpo=21513]: Speedup some properties of IP addresses (IPv4Address, IPv6Address) such as .is_private or .is_multicast.

bpo-21137 [https://bugs.python.org/issue?@action=redirect&bpo=21137]: Improve the repr for threading.Lock() and its variants by showing the “locked” or “unlocked” status. Patch by Berker Peksag.

bpo-21538 [https://bugs.python.org/issue?@action=redirect&bpo=21538]: The plistlib module now supports loading of binary plist files when reference or offset size is not a power of two.

bpo-21455 [https://bugs.python.org/issue?@action=redirect&bpo=21455]: Add a default backlog to socket.listen().

bpo-21525 [https://bugs.python.org/issue?@action=redirect&bpo=21525]: Most Tkinter methods which accepted tuples now accept lists too.

bpo-22166 [https://bugs.python.org/issue?@action=redirect&bpo=22166]: With the assistance of a new internal _codecs._forget_codec helping function, test_codecs now clears the encoding caches to avoid the appearance of a reference leak

bpo-22236 [https://bugs.python.org/issue?@action=redirect&bpo=22236]: Tkinter tests now don’t reuse default root window. New root window is created for every test class.

bpo-10744 [https://bugs.python.org/issue?@action=redirect&bpo=10744]: Fix PEP 3118 [https://peps.python.org/pep-3118/] format strings on ctypes objects with a nontrivial shape.

bpo-20826 [https://bugs.python.org/issue?@action=redirect&bpo=20826]: Optimize ipaddress.collapse_addresses().

bpo-21487 [https://bugs.python.org/issue?@action=redirect&bpo=21487]: Optimize ipaddress.summarize_address_range() and ipaddress.{IPv4Network,IPv6Network}.subnets().

bpo-21486 [https://bugs.python.org/issue?@action=redirect&bpo=21486]: Optimize parsing of netmasks in ipaddress.IPv4Network and ipaddress.IPv6Network.

bpo-13916 [https://bugs.python.org/issue?@action=redirect&bpo=13916]: Disallowed the surrogatepass error handler for non UTF-* encodings.

bpo-20998 [https://bugs.python.org/issue?@action=redirect&bpo=20998]: Fixed re.fullmatch() of repeated single character pattern with ignore case. Original patch by Matthew Barnett.

bpo-21075 [https://bugs.python.org/issue?@action=redirect&bpo=21075]: fileinput.FileInput now reads bytes from standard stream if binary mode is specified. Patch by Sam Kimbrel.

bpo-19775 [https://bugs.python.org/issue?@action=redirect&bpo=19775]: Add a samefile() method to pathlib Path objects. Initial patch by Vajrasky Kok.

bpo-21226 [https://bugs.python.org/issue?@action=redirect&bpo=21226]: Set up modules properly in PyImport_ExecCodeModuleObject (and friends).

bpo-21398 [https://bugs.python.org/issue?@action=redirect&bpo=21398]: Fix a unicode error in the pydoc pager when the documentation contains characters not encodable to the stdout encoding.

bpo-16531 [https://bugs.python.org/issue?@action=redirect&bpo=16531]: ipaddress.IPv4Network and ipaddress.IPv6Network now accept an (address, netmask) tuple argument, so as to easily construct network objects from existing addresses.

bpo-21156 [https://bugs.python.org/issue?@action=redirect&bpo=21156]: importlib.abc.InspectLoader.source_to_code() is now a staticmethod.

bpo-21424 [https://bugs.python.org/issue?@action=redirect&bpo=21424]: Simplified and optimized heaqp.nlargest() and nmsmallest() to make fewer tuple comparisons.

bpo-21396 [https://bugs.python.org/issue?@action=redirect&bpo=21396]: Fix TextIOWrapper(…, write_through=True) to not force a flush() on the underlying binary stream. Patch by akira.

bpo-18314 [https://bugs.python.org/issue?@action=redirect&bpo=18314]: Unlink now removes junctions on Windows. Patch by Kim Gräsman

bpo-21088 [https://bugs.python.org/issue?@action=redirect&bpo=21088]: Bugfix for curses.window.addch() regression in 3.4.0. In porting to Argument Clinic, the first two arguments were reversed.

bpo-21407 [https://bugs.python.org/issue?@action=redirect&bpo=21407]: _decimal: The module now supports function signatures.

bpo-10650 [https://bugs.python.org/issue?@action=redirect&bpo=10650]: Remove the non-standard ‘watchexp’ parameter from the Decimal.quantize() method in the Python version. It had never been present in the C version.

bpo-21469 [https://bugs.python.org/issue?@action=redirect&bpo=21469]: Reduced the risk of false positives in robotparser by checking to make sure that robots.txt has been read or does not exist prior to returning True in can_fetch().

bpo-19414 [https://bugs.python.org/issue?@action=redirect&bpo=19414]: Have the OrderedDict mark deleted links as unusable. This gives an early failure if the link is deleted during iteration.

bpo-21421 [https://bugs.python.org/issue?@action=redirect&bpo=21421]: Add __slots__ to the MappingViews ABC. Patch by Josh Rosenberg.

bpo-21101 [https://bugs.python.org/issue?@action=redirect&bpo=21101]: Eliminate double hashing in the C speed-up code for collections.Counter().

bpo-21321 [https://bugs.python.org/issue?@action=redirect&bpo=21321]: itertools.islice() now releases the reference to the source iterator when the slice is exhausted. Patch by Anton Afanasyev.

bpo-21057 [https://bugs.python.org/issue?@action=redirect&bpo=21057]: TextIOWrapper now allows the underlying binary stream’s read() or read1() method to return an arbitrary bytes-like object (such as a memoryview). Patch by Nikolaus Rath.

bpo-20951 [https://bugs.python.org/issue?@action=redirect&bpo=20951]: SSLSocket.send() now raises either SSLWantReadError or SSLWantWriteError on a non-blocking socket if the operation would block. Previously, it would return 0. Patch by Nikolaus Rath.

bpo-13248 [https://bugs.python.org/issue?@action=redirect&bpo=13248]: removed previously deprecated asyncore.dispatcher __getattr__ cheap inheritance hack.

bpo-9815 [https://bugs.python.org/issue?@action=redirect&bpo=9815]: assertRaises now tries to clear references to local variables in the exception’s traceback.

bpo-19940 [https://bugs.python.org/issue?@action=redirect&bpo=19940]: ssl.cert_time_to_seconds() now interprets the given time string in the UTC timezone (as specified in RFC 5280), not the local timezone.

bpo-13204 [https://bugs.python.org/issue?@action=redirect&bpo=13204]: Calling sys.flags.__new__ would crash the interpreter, now it raises a TypeError.

bpo-19385 [https://bugs.python.org/issue?@action=redirect&bpo=19385]: Make operations on a closed dbm.dumb database always raise the same exception.

bpo-21207 [https://bugs.python.org/issue?@action=redirect&bpo=21207]: Detect when the os.urandom cached fd has been closed or replaced, and open it anew.

bpo-21291 [https://bugs.python.org/issue?@action=redirect&bpo=21291]: subprocess’s Popen.wait() is now thread safe so that multiple threads may be calling wait() or poll() on a Popen instance at the same time without losing the Popen.returncode value.

bpo-21127 [https://bugs.python.org/issue?@action=redirect&bpo=21127]: Path objects can now be instantiated from str subclass instances (such as numpy.str_).

bpo-15002 [https://bugs.python.org/issue?@action=redirect&bpo=15002]: urllib.response object to use _TemporaryFileWrapper (and _TemporaryFileCloser) facility. Provides a better way to handle file descriptor close. Patch contributed by Christian Theune.

bpo-12220 [https://bugs.python.org/issue?@action=redirect&bpo=12220]: mindom now raises a custom ValueError indicating it doesn’t support spaces in URIs instead of letting a ‘split’ ValueError bubble up.

bpo-21068 [https://bugs.python.org/issue?@action=redirect&bpo=21068]: The ssl.PROTOCOL* constants are now enum members.

bpo-21276 [https://bugs.python.org/issue?@action=redirect&bpo=21276]: posixmodule: Don’t define USE_XATTRS on KFreeBSD and the Hurd.

bpo-21262 [https://bugs.python.org/issue?@action=redirect&bpo=21262]: New method assert_not_called for Mock. It raises AssertionError if the mock has been called.

bpo-21238 [https://bugs.python.org/issue?@action=redirect&bpo=21238]: New keyword argument unsafe to Mock. It raises AttributeError in case of an attribute startswith assert or assret.

bpo-20896 [https://bugs.python.org/issue?@action=redirect&bpo=20896]: ssl.get_server_certificate() now uses PROTOCOL_SSLv23, not PROTOCOL_SSLv3, for maximum compatibility.

bpo-21239 [https://bugs.python.org/issue?@action=redirect&bpo=21239]: patch.stopall() didn’t work deterministically when the same name was patched more than once.

bpo-21203 [https://bugs.python.org/issue?@action=redirect&bpo=21203]: Updated fileConfig and dictConfig to remove inconsistencies. Thanks to Jure Koren for the patch.

bpo-21222 [https://bugs.python.org/issue?@action=redirect&bpo=21222]: Passing name keyword argument to mock.create_autospec now works.

bpo-21197 [https://bugs.python.org/issue?@action=redirect&bpo=21197]: Add lib64 -> lib symlink in venvs on 64-bit non-OS X POSIX.

bpo-17498 [https://bugs.python.org/issue?@action=redirect&bpo=17498]: Some SMTP servers disconnect after certain errors, violating strict RFC conformance. Instead of losing the error code when we issue the subsequent RSET, smtplib now returns the error code and defers raising the SMTPServerDisconnected error until the next command is issued.

bpo-17826 [https://bugs.python.org/issue?@action=redirect&bpo=17826]: setting an iterable side_effect on a mock function created by create_autospec now works. Patch by Kushal Das.

bpo-7776 [https://bugs.python.org/issue?@action=redirect&bpo=7776]: Fix Host: header and reconnection when using http.client.HTTPConnection.set_tunnel(). Patch by Nikolaus Rath.

bpo-20968 [https://bugs.python.org/issue?@action=redirect&bpo=20968]: unittest.mock.MagicMock now supports division. Patch by Johannes Baiter.

bpo-21529 [https://bugs.python.org/issue?@action=redirect&bpo=21529]: Fix arbitrary memory access in JSONDecoder.raw_decode with a negative second parameter. Bug reported by Guido Vranken. (See also: CVE 2014-4616 [https://www.cve.org/CVERecord?id=CVE-2014-4616])

bpo-21169 [https://bugs.python.org/issue?@action=redirect&bpo=21169]: getpass now handles non-ascii characters that the input stream encoding cannot encode by re-encoding using the replace error handler.

bpo-21171 [https://bugs.python.org/issue?@action=redirect&bpo=21171]: Fixed undocumented filter API of the rot13 codec. Patch by Berker Peksag.

bpo-20539 [https://bugs.python.org/issue?@action=redirect&bpo=20539]: Improved math.factorial error message for large positive inputs and changed exception type (OverflowError -> ValueError) for large negative inputs.

bpo-21172 [https://bugs.python.org/issue?@action=redirect&bpo=21172]: isinstance check relaxed from dict to collections.Mapping.

bpo-21155 [https://bugs.python.org/issue?@action=redirect&bpo=21155]: asyncio.EventLoop.create_unix_server() now raises a ValueError if path and sock are specified at the same time.

bpo-21136 [https://bugs.python.org/issue?@action=redirect&bpo=21136]: Avoid unnecessary normalization of Fractions resulting from power and other operations. Patch by Raymond Hettinger.

bpo-17621 [https://bugs.python.org/issue?@action=redirect&bpo=17621]: Introduce importlib.util.LazyLoader.

bpo-21076 [https://bugs.python.org/issue?@action=redirect&bpo=21076]: signal module constants were turned into enums. Patch by Giampaolo Rodola’.

bpo-20636 [https://bugs.python.org/issue?@action=redirect&bpo=20636]: Improved the repr of Tkinter widgets.

bpo-19505 [https://bugs.python.org/issue?@action=redirect&bpo=19505]: The items, keys, and values views of OrderedDict now support reverse iteration using reversed().

bpo-21149 [https://bugs.python.org/issue?@action=redirect&bpo=21149]: Improved thread-safety in logging cleanup during interpreter shutdown. Thanks to Devin Jeanpierre for the patch.

bpo-21058 [https://bugs.python.org/issue?@action=redirect&bpo=21058]: Fix a leak of file descriptor in tempfile.NamedTemporaryFile(), close the file descriptor if io.open() fails

bpo-21200 [https://bugs.python.org/issue?@action=redirect&bpo=21200]: Return None from pkgutil.get_loader() when __spec__ is missing.

bpo-21013 [https://bugs.python.org/issue?@action=redirect&bpo=21013]: Enhance ssl.create_default_context() when used for server side sockets to provide better security by default.

bpo-20145 [https://bugs.python.org/issue?@action=redirect&bpo=20145]: assertRaisesRegex and assertWarnsRegex now raise a TypeError if the second argument is not a string or compiled regex.

bpo-20633 [https://bugs.python.org/issue?@action=redirect&bpo=20633]: Replace relative import by absolute import.

bpo-20980 [https://bugs.python.org/issue?@action=redirect&bpo=20980]: Stop wrapping exception when using ThreadPool.

bpo-21082 [https://bugs.python.org/issue?@action=redirect&bpo=21082]: In os.makedirs, do not set the process-wide umask. Note this changes behavior of makedirs when exist_ok=True.

bpo-20990 [https://bugs.python.org/issue?@action=redirect&bpo=20990]: Fix issues found by pyflakes for multiprocessing.

bpo-21015 [https://bugs.python.org/issue?@action=redirect&bpo=21015]: SSL contexts will now automatically select an elliptic curve for ECDH key exchange on OpenSSL 1.0.2 and later, and otherwise default to “prime256v1”.

bpo-21000 [https://bugs.python.org/issue?@action=redirect&bpo=21000]: Improve the command-line interface of json.tool.

bpo-20995 [https://bugs.python.org/issue?@action=redirect&bpo=20995]: Enhance default ciphers used by the ssl module to enable better security and prioritize perfect forward secrecy.

bpo-20884 [https://bugs.python.org/issue?@action=redirect&bpo=20884]: Don’t assume that __file__ is defined on importlib.__init__.

bpo-21499 [https://bugs.python.org/issue?@action=redirect&bpo=21499]: Ignore __builtins__ in several test_importlib.test_api tests.

bpo-20627 [https://bugs.python.org/issue?@action=redirect&bpo=20627]: xmlrpc.client.ServerProxy is now a context manager.

bpo-19165 [https://bugs.python.org/issue?@action=redirect&bpo=19165]: The formatter module now raises DeprecationWarning instead of PendingDeprecationWarning.

bpo-13936 [https://bugs.python.org/issue?@action=redirect&bpo=13936]: Remove the ability of datetime.time instances to be considered false in boolean contexts.

bpo-18931 [https://bugs.python.org/issue?@action=redirect&bpo=18931]: selectors module now supports /dev/poll on Solaris. Patch by Giampaolo Rodola’.

bpo-19977 [https://bugs.python.org/issue?@action=redirect&bpo=19977]: When the LC_TYPE locale is the POSIX locale (C locale), sys.stdin and sys.stdout are now using the surrogateescape error handler, instead of the strict error handler.

bpo-20574 [https://bugs.python.org/issue?@action=redirect&bpo=20574]: Implement incremental decoder for cp65001 code (Windows code page 65001, Microsoft UTF-8).

bpo-20879 [https://bugs.python.org/issue?@action=redirect&bpo=20879]: Delay the initialization of encoding and decoding tables for base32, ascii85 and base85 codecs in the base64 module, and delay the initialization of the unquote_to_bytes() table of the urllib.parse module, to not waste memory if these modules are not used.

bpo-19157 [https://bugs.python.org/issue?@action=redirect&bpo=19157]: Include the broadcast address in the usable hosts for IPv6 in ipaddress.

bpo-11599 [https://bugs.python.org/issue?@action=redirect&bpo=11599]: When an external command (e.g. compiler) fails, distutils now prints out the whole command line (instead of just the command name) if the environment variable DISTUTILS_DEBUG is set.

bpo-4931 [https://bugs.python.org/issue?@action=redirect&bpo=4931]: distutils should not produce unhelpful “error: None” messages anymore. distutils.util.grok_environment_error is kept but doc-deprecated.

bpo-20875 [https://bugs.python.org/issue?@action=redirect&bpo=20875]: Prevent possible gzip “‘read’ is not defined” NameError. Patch by Claudiu Popa.

bpo-11558 [https://bugs.python.org/issue?@action=redirect&bpo=11558]: email.message.Message.attach now returns a more useful error message if attach is called on a message for which is_multipart is False.

bpo-20283 [https://bugs.python.org/issue?@action=redirect&bpo=20283]: RE pattern methods now accept the string keyword parameters as documented. The pattern and source keyword parameters are left as deprecated aliases.

bpo-20778 [https://bugs.python.org/issue?@action=redirect&bpo=20778]: Fix modulefinder to work with bytecode-only modules.

bpo-20791 [https://bugs.python.org/issue?@action=redirect&bpo=20791]: copy.copy() now doesn’t make a copy when the input is a bytes object. Initial patch by Peter Otten.

bpo-19748 [https://bugs.python.org/issue?@action=redirect&bpo=19748]: On AIX, time.mktime() now raises an OverflowError for year outsize range [1902; 2037].

bpo-19573 [https://bugs.python.org/issue?@action=redirect&bpo=19573]: inspect.signature: Use enum for parameter kind constants.

bpo-20726 [https://bugs.python.org/issue?@action=redirect&bpo=20726]: inspect.signature: Make Signature and Parameter picklable.

bpo-17373 [https://bugs.python.org/issue?@action=redirect&bpo=17373]: Add inspect.Signature.from_callable method.

bpo-20378 [https://bugs.python.org/issue?@action=redirect&bpo=20378]: Improve repr of inspect.Signature and inspect.Parameter.

bpo-20816 [https://bugs.python.org/issue?@action=redirect&bpo=20816]: Fix inspect.getcallargs() to raise correct TypeError for missing keyword-only arguments. Patch by Jeremiah Lowin.

bpo-20817 [https://bugs.python.org/issue?@action=redirect&bpo=20817]: Fix inspect.getcallargs() to fail correctly if more than 3 arguments are missing. Patch by Jeremiah Lowin.

bpo-6676 [https://bugs.python.org/issue?@action=redirect&bpo=6676]: Ensure a meaningful exception is raised when attempting to parse more than one XML document per pyexpat xmlparser instance. (Original patches by Hirokazu Yamamoto and Amaury Forgeot d’Arc, with suggested wording by David Gutteridge)

bpo-21117 [https://bugs.python.org/issue?@action=redirect&bpo=21117]: Fix inspect.signature to better support functools.partial. Due to the specifics of functools.partial implementation, positional-or-keyword arguments passed as keyword arguments become keyword-only.

bpo-20334 [https://bugs.python.org/issue?@action=redirect&bpo=20334]: inspect.Signature and inspect.Parameter are now hashable. Thanks to Antony Lee for bug reports and suggestions.

bpo-15916 [https://bugs.python.org/issue?@action=redirect&bpo=15916]: doctest.DocTestSuite returns an empty unittest.TestSuite instead of raising ValueError if it finds no tests

bpo-21209 [https://bugs.python.org/issue?@action=redirect&bpo=21209]: Fix asyncio.tasks.CoroWrapper to workaround a bug in yield-from implementation in CPythons prior to 3.4.1.

asyncio: Add gi_{frame,running,code} properties to CoroWrapper (upstream bpo-163 [https://bugs.python.org/issue?@action=redirect&bpo=163]).

bpo-21311 [https://bugs.python.org/issue?@action=redirect&bpo=21311]: Avoid exception in _osx_support with non-standard compiler configurations. Patch by John Szakmeister.

bpo-11571 [https://bugs.python.org/issue?@action=redirect&bpo=11571]: Ensure that the turtle window becomes the topmost window when launched on OS X.

bpo-21801 [https://bugs.python.org/issue?@action=redirect&bpo=21801]: Validate that __signature__ is None or an instance of Signature.

bpo-21923 [https://bugs.python.org/issue?@action=redirect&bpo=21923]: Prevent AttributeError in distutils.sysconfig.customize_compiler due to possible uninitialized _config_vars.

bpo-21323 [https://bugs.python.org/issue?@action=redirect&bpo=21323]: Fix http.server to again handle scripts in CGI subdirectories, broken by the fix for security bpo-19435 [https://bugs.python.org/issue?@action=redirect&bpo=19435]. Patch by Zach Byrne.

bpo-22733 [https://bugs.python.org/issue?@action=redirect&bpo=22733]: Fix ffi_prep_args not zero-extending argument values correctly on 64-bit Windows.

bpo-23302 [https://bugs.python.org/issue?@action=redirect&bpo=23302]: Default to TCP_NODELAY=1 upon establishing an HTTPConnection. Removed use of hard-coded MSS as it’s an optimization that’s no longer needed with Nagle disabled.

IDLE

bpo-20577 [https://bugs.python.org/issue?@action=redirect&bpo=20577]: Configuration of the max line length for the FormatParagraph extension has been moved from the General tab of the Idle preferences dialog to the FormatParagraph tab of the Config Extensions dialog. Patch by Tal Einat.

bpo-16893 [https://bugs.python.org/issue?@action=redirect&bpo=16893]: Update Idle doc chapter to match current Idle and add new information.

bpo-3068 [https://bugs.python.org/issue?@action=redirect&bpo=3068]: Add Idle extension configuration dialog to Options menu. Changes are written to HOME/.idlerc/config-extensions.cfg. Original patch by Tal Einat.

bpo-16233 [https://bugs.python.org/issue?@action=redirect&bpo=16233]: A module browser (File : Class Browser, Alt+C) requires an editor window with a filename. When Class Browser is requested otherwise, from a shell, output window, or ‘Untitled’ editor, Idle no longer displays an error box. It now pops up an Open Module box (Alt+M). If a valid name is entered and a module is opened, a corresponding browser is also opened.

bpo-4832 [https://bugs.python.org/issue?@action=redirect&bpo=4832]: Save As to type Python files automatically adds .py to the name you enter (even if your system does not display it). Some systems automatically add .txt when type is Text files.

bpo-21986 [https://bugs.python.org/issue?@action=redirect&bpo=21986]: Code objects are not normally pickled by the pickle module. To match this, they are no longer pickled when running under Idle.

bpo-17390 [https://bugs.python.org/issue?@action=redirect&bpo=17390]: Adjust Editor window title; remove ‘Python’, move version to end.

bpo-14105 [https://bugs.python.org/issue?@action=redirect&bpo=14105]: Idle debugger breakpoints no longer disappear when inserting or deleting lines.

bpo-17172 [https://bugs.python.org/issue?@action=redirect&bpo=17172]: Turtledemo can now be run from Idle. Currently, the entry is on the Help menu, but it may move to Run. Patch by Ramchandra Apt and Lita Cho.

bpo-21765 [https://bugs.python.org/issue?@action=redirect&bpo=21765]: Add support for non-ascii identifiers to HyperParser.

bpo-21940 [https://bugs.python.org/issue?@action=redirect&bpo=21940]: Add unittest for WidgetRedirector. Initial patch by Saimadhav Heblikar.

bpo-18592 [https://bugs.python.org/issue?@action=redirect&bpo=18592]: Add unittest for SearchDialogBase. Patch by Phil Webster.

bpo-21694 [https://bugs.python.org/issue?@action=redirect&bpo=21694]: Add unittest for ParenMatch. Patch by Saimadhav Heblikar.

bpo-21686 [https://bugs.python.org/issue?@action=redirect&bpo=21686]: add unittest for HyperParser. Original patch by Saimadhav Heblikar.

bpo-12387 [https://bugs.python.org/issue?@action=redirect&bpo=12387]: Add missing upper(lower)case versions of default Windows key bindings for Idle so Caps Lock does not disable them. Patch by Roger Serwy.

bpo-21695 [https://bugs.python.org/issue?@action=redirect&bpo=21695]: Closing a Find-in-files output window while the search is still in progress no longer closes Idle.

bpo-18910 [https://bugs.python.org/issue?@action=redirect&bpo=18910]: Add unittest for textView. Patch by Phil Webster.

bpo-18292 [https://bugs.python.org/issue?@action=redirect&bpo=18292]: Add unittest for AutoExpand. Patch by Saihadhav Heblikar.

bpo-18409 [https://bugs.python.org/issue?@action=redirect&bpo=18409]: Add unittest for AutoComplete. Patch by Phil Webster.

bpo-21477 [https://bugs.python.org/issue?@action=redirect&bpo=21477]: htest.py - Improve framework, complete set of tests. Patches by Saimadhav Heblikar

bpo-18104 [https://bugs.python.org/issue?@action=redirect&bpo=18104]: Add idlelib/idle_test/htest.py with a few sample tests to begin consolidating and improving human-validated tests of Idle. Change other files as needed to work with htest. Running the module as __main__ runs all tests.

bpo-21139 [https://bugs.python.org/issue?@action=redirect&bpo=21139]: Change default paragraph width to 72, the PEP 8 [https://peps.python.org/pep-0008/] recommendation.

bpo-21284 [https://bugs.python.org/issue?@action=redirect&bpo=21284]: Paragraph reformat test passes after user changes reformat width.

bpo-17654 [https://bugs.python.org/issue?@action=redirect&bpo=17654]: Ensure IDLE menus are customized properly on OS X for non-framework builds and for all variants of Tk.

bpo-23180 [https://bugs.python.org/issue?@action=redirect&bpo=23180]: Rename IDLE “Windows” menu item to “Window”. Patch by Al Sweigart.

Build

bpo-15506 [https://bugs.python.org/issue?@action=redirect&bpo=15506]: Use standard PKG_PROG_PKG_CONFIG autoconf macro in the configure script.

bpo-22935 [https://bugs.python.org/issue?@action=redirect&bpo=22935]: Allow the ssl module to be compiled if openssl doesn’t support SSL 3.

bpo-22592 [https://bugs.python.org/issue?@action=redirect&bpo=22592]: Drop support of the Borland C compiler to build Python. The distutils module still supports it to build extensions.

bpo-22591 [https://bugs.python.org/issue?@action=redirect&bpo=22591]: Drop support of MS-DOS, especially of the DJGPP compiler (MS-DOS port of GCC).

bpo-16537 [https://bugs.python.org/issue?@action=redirect&bpo=16537]: Check whether self.extensions is empty in setup.py. Patch by Jonathan Hosmer.

bpo-22359 [https://bugs.python.org/issue?@action=redirect&bpo=22359]: Remove incorrect uses of recursive make. Patch by Jonas Wagner.

bpo-21958 [https://bugs.python.org/issue?@action=redirect&bpo=21958]: Define HAVE_ROUND when building with Visual Studio 2013 and above. Patch by Zachary Turner.

bpo-18093 [https://bugs.python.org/issue?@action=redirect&bpo=18093]: the programs that embed the CPython runtime are now in a separate “Programs” directory, rather than being kept in the Modules directory.

bpo-15759 [https://bugs.python.org/issue?@action=redirect&bpo=15759]: “make suspicious”, “make linkcheck” and “make doctest” in Doc/ now display special message when and only when there are failures.

bpo-21141 [https://bugs.python.org/issue?@action=redirect&bpo=21141]: The Windows build process no longer attempts to find Perl, instead relying on OpenSSL source being configured and ready to build. The PCbuild\build_ssl.py script has been re-written and re-named to PCbuild\prepare_ssl.py, and takes care of configuring OpenSSL source for both 32 and 64 bit platforms. OpenSSL sources obtained from svn.python.org will always be pre-configured and ready to build.

bpo-21037 [https://bugs.python.org/issue?@action=redirect&bpo=21037]: Add a build option to enable AddressSanitizer support.

bpo-19962 [https://bugs.python.org/issue?@action=redirect&bpo=19962]: The Windows build process now creates “python.bat” in the root of the source tree, which passes all arguments through to the most recently built interpreter.

bpo-21285 [https://bugs.python.org/issue?@action=redirect&bpo=21285]: Refactor and fix curses configure check to always search in a ncursesw directory.

bpo-15234 [https://bugs.python.org/issue?@action=redirect&bpo=15234]: For BerkeleyDB and Sqlite, only add the found library and include directories if they aren’t already being searched. This avoids an explicit runtime library dependency.

bpo-17861 [https://bugs.python.org/issue?@action=redirect&bpo=17861]: Tools/scripts/generate_opcode_h.py automatically regenerates Include/opcode.h from Lib/opcode.py if the latter gets any change.

bpo-20644 [https://bugs.python.org/issue?@action=redirect&bpo=20644]: OS X installer build support for documentation build changes in 3.4.1: assume externally supplied sphinx-build is available in /usr/bin.

bpo-20022 [https://bugs.python.org/issue?@action=redirect&bpo=20022]: Eliminate use of deprecated bundlebuilder in OS X builds.

bpo-15968 [https://bugs.python.org/issue?@action=redirect&bpo=15968]: Incorporated Tcl, Tk, and Tix builds into the Windows build solution.

bpo-17095 [https://bugs.python.org/issue?@action=redirect&bpo=17095]: Fix Modules/Setup shared support.

bpo-21811 [https://bugs.python.org/issue?@action=redirect&bpo=21811]: Anticipated fixes to support OS X versions > 10.9.

bpo-21166 [https://bugs.python.org/issue?@action=redirect&bpo=21166]: Prevent possible segfaults and other random failures of python –generate-posix-vars in pybuilddir.txt build target.

bpo-18096 [https://bugs.python.org/issue?@action=redirect&bpo=18096]: Fix library order returned by python-config.

bpo-17219 [https://bugs.python.org/issue?@action=redirect&bpo=17219]: Add library build dir for Python extension cross-builds.

bpo-22919 [https://bugs.python.org/issue?@action=redirect&bpo=22919]: Windows build updated to support VC 14.0 (Visual Studio 2015), which will be used for the official release.

bpo-21236 [https://bugs.python.org/issue?@action=redirect&bpo=21236]: Build _msi.pyd with cabinet.lib instead of fci.lib

bpo-17128 [https://bugs.python.org/issue?@action=redirect&bpo=17128]: Use private version of OpenSSL for OS X 10.5+ installer.

C API

bpo-14203 [https://bugs.python.org/issue?@action=redirect&bpo=14203]: Remove obsolete support for view==NULL in PyBuffer_FillInfo(), bytearray_getbuffer(), bytesiobuf_getbuffer() and array_buffer_getbuf(). All functions now raise BufferError in that case.

bpo-22445 [https://bugs.python.org/issue?@action=redirect&bpo=22445]: PyBuffer_IsContiguous() now implements precise contiguity tests, compatible with NumPy’s NPY_RELAXED_STRIDES_CHECKING compilation flag. Previously the function reported false negatives for corner cases.

bpo-22079 [https://bugs.python.org/issue?@action=redirect&bpo=22079]: PyType_Ready() now checks that statically allocated type has no dynamically allocated bases.

bpo-22453 [https://bugs.python.org/issue?@action=redirect&bpo=22453]: Removed non-documented macro PyObject_REPR().

bpo-18395 [https://bugs.python.org/issue?@action=redirect&bpo=18395]: Rename _Py_char2wchar() to Py_DecodeLocale(), rename _Py_wchar2char() to Py_EncodeLocale(), and document these functions.

bpo-21233 [https://bugs.python.org/issue?@action=redirect&bpo=21233]: Add new C functions: PyMem_RawCalloc(), PyMem_Calloc(), PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) is now using calloc() instead of malloc() for large objects which is faster and use less memory.

bpo-20942 [https://bugs.python.org/issue?@action=redirect&bpo=20942]: PyImport_ImportFrozenModuleObject() no longer sets __file__ to match what importlib does; this affects _frozen_importlib as well as any module loaded using imp.init_frozen().

Documentation

bpo-19548 [https://bugs.python.org/issue?@action=redirect&bpo=19548]: Update the codecs module documentation to better cover the distinction between text encodings and other codecs, together with other clarifications. Patch by Martin Panter.

bpo-22394 [https://bugs.python.org/issue?@action=redirect&bpo=22394]: Doc/Makefile now supports make venv PYTHON=../python to create a venv for generating the documentation, e.g., make html PYTHON=venv/bin/python3.

bpo-21514 [https://bugs.python.org/issue?@action=redirect&bpo=21514]: The documentation of the json module now refers to new JSON RFC 7159 instead of obsoleted RFC 4627.

bpo-21777 [https://bugs.python.org/issue?@action=redirect&bpo=21777]: The binary sequence methods on bytes and bytearray are now documented explicitly, rather than assuming users will be able to derive the expected behaviour from the behaviour of the corresponding str methods.

bpo-6916 [https://bugs.python.org/issue?@action=redirect&bpo=6916]: undocument deprecated asynchat.fifo class.

bpo-17386 [https://bugs.python.org/issue?@action=redirect&bpo=17386]: Expanded functionality of the Doc/make.bat script to make it much more comparable to Doc/Makefile.

bpo-21312 [https://bugs.python.org/issue?@action=redirect&bpo=21312]: Update the thread_foobar.h template file to include newer threading APIs. Patch by Jack McCracken.

bpo-21043 [https://bugs.python.org/issue?@action=redirect&bpo=21043]: Remove the recommendation for specific CA organizations and to mention the ability to load the OS certificates.

bpo-20765 [https://bugs.python.org/issue?@action=redirect&bpo=20765]: Add missing documentation for PurePath.with_name() and PurePath.with_suffix().

bpo-19407 [https://bugs.python.org/issue?@action=redirect&bpo=19407]: New package installation and distribution guides based on the Python Packaging Authority tools. Existing guides have been retained as legacy links from the distutils docs, as they still contain some required reference material for tool developers that isn’t recorded anywhere else.

bpo-19697 [https://bugs.python.org/issue?@action=redirect&bpo=19697]: Document cases where __main__.__spec__ is None.

Tests

bpo-18982 [https://bugs.python.org/issue?@action=redirect&bpo=18982]: Add tests for CLI of the calendar module.

bpo-19548 [https://bugs.python.org/issue?@action=redirect&bpo=19548]: Added some additional checks to test_codecs to ensure that statements in the updated documentation remain accurate. Patch by Martin Panter.

bpo-22838 [https://bugs.python.org/issue?@action=redirect&bpo=22838]: All test_re tests now work with unittest test discovery.

bpo-22173 [https://bugs.python.org/issue?@action=redirect&bpo=22173]: Update lib2to3 tests to use unittest test discovery.

bpo-16000 [https://bugs.python.org/issue?@action=redirect&bpo=16000]: Convert test_curses to use unittest.

bpo-21456 [https://bugs.python.org/issue?@action=redirect&bpo=21456]: Skip two tests in test_urllib2net.py if _ssl module not present. Patch by Remi Pointel.

bpo-20746 [https://bugs.python.org/issue?@action=redirect&bpo=20746]: Fix test_pdb to run in refleak mode (-R). Patch by Xavier de Gaye.

bpo-22060 [https://bugs.python.org/issue?@action=redirect&bpo=22060]: test_ctypes has been somewhat cleaned up and simplified; it now uses unittest test discovery to find its tests.

bpo-22104 [https://bugs.python.org/issue?@action=redirect&bpo=22104]: regrtest.py no longer holds a reference to the suite of tests loaded from test modules that don’t define test_main().

bpo-22111 [https://bugs.python.org/issue?@action=redirect&bpo=22111]: Assorted cleanups in test_imaplib. Patch by Milan Oberkirch.

bpo-22002 [https://bugs.python.org/issue?@action=redirect&bpo=22002]: Added load_package_tests function to test.support and used it to implement/augment test discovery in test_asyncio, test_email, test_importlib, test_json, and test_tools.

bpo-21976 [https://bugs.python.org/issue?@action=redirect&bpo=21976]: Fix test_ssl to accept LibreSSL version strings. Thanks to William Orr.

bpo-21918 [https://bugs.python.org/issue?@action=redirect&bpo=21918]: Converted test_tools from a module to a package containing separate test files for each tested script.

bpo-9554 [https://bugs.python.org/issue?@action=redirect&bpo=9554]: Use modern unittest features in test_argparse. Initial patch by Denver Coneybeare and Radu Voicilas.

bpo-20155 [https://bugs.python.org/issue?@action=redirect&bpo=20155]: Changed HTTP method names in failing tests in test_httpservers so that packet filtering software (specifically Windows Base Filtering Engine) does not interfere with the transaction semantics expected by the tests.

bpo-19493 [https://bugs.python.org/issue?@action=redirect&bpo=19493]: Refactored the ctypes test package to skip tests explicitly rather than silently.

bpo-18492 [https://bugs.python.org/issue?@action=redirect&bpo=18492]: All resources are now allowed when tests are not run by regrtest.py.

bpo-21634 [https://bugs.python.org/issue?@action=redirect&bpo=21634]: Fix pystone micro-benchmark: use floor division instead of true division to benchmark integers instead of floating-point numbers. Set pystone version to 1.2. Patch written by Lennart Regebro.

bpo-21605 [https://bugs.python.org/issue?@action=redirect&bpo=21605]: Added tests for Tkinter images.

bpo-21493 [https://bugs.python.org/issue?@action=redirect&bpo=21493]: Added test for ntpath.expanduser(). Original patch by Claudiu Popa.

bpo-19925 [https://bugs.python.org/issue?@action=redirect&bpo=19925]: Added tests for the spwd module. Original patch by Vajrasky Kok.

bpo-21522 [https://bugs.python.org/issue?@action=redirect&bpo=21522]: Added Tkinter tests for Listbox.itemconfigure(), PanedWindow.paneconfigure(), and Menu.entryconfigure().

bpo-17756 [https://bugs.python.org/issue?@action=redirect&bpo=17756]: Fix test_code test when run from the installed location.

bpo-17752 [https://bugs.python.org/issue?@action=redirect&bpo=17752]: Fix distutils tests when run from the installed location.

bpo-18604 [https://bugs.python.org/issue?@action=redirect&bpo=18604]: Consolidated checks for GUI availability. All platforms now at least check whether Tk can be instantiated when the GUI resource is requested.

bpo-21275 [https://bugs.python.org/issue?@action=redirect&bpo=21275]: Fix a socket test on KFreeBSD.

bpo-21223 [https://bugs.python.org/issue?@action=redirect&bpo=21223]: Pass test_site/test_startup_imports when some of the extensions are built as builtins.

bpo-20635 [https://bugs.python.org/issue?@action=redirect&bpo=20635]: Added tests for Tk geometry managers.

Add test case for freeze.

bpo-20743 [https://bugs.python.org/issue?@action=redirect&bpo=20743]: Fix a reference leak in test_tcl.

bpo-21097 [https://bugs.python.org/issue?@action=redirect&bpo=21097]: Move test_namespace_pkgs into test_importlib.

bpo-21503 [https://bugs.python.org/issue?@action=redirect&bpo=21503]: Use test_both() consistently in test_importlib.

bpo-20939 [https://bugs.python.org/issue?@action=redirect&bpo=20939]: Avoid various network test failures due to new redirect of http://www.python.org/ to https://www.python.org: use http://www.example.com instead.

bpo-20668 [https://bugs.python.org/issue?@action=redirect&bpo=20668]: asyncio tests no longer rely on tests.txt file. (Patch by Vajrasky Kok)

bpo-21093 [https://bugs.python.org/issue?@action=redirect&bpo=21093]: Prevent failures of ctypes test_macholib on OS X if a copy of libz exists in $HOME/lib or /usr/local/lib.

bpo-22770 [https://bugs.python.org/issue?@action=redirect&bpo=22770]: Prevent some Tk segfaults on OS X when running gui tests.

bpo-23211 [https://bugs.python.org/issue?@action=redirect&bpo=23211]: Workaround test_logging failure on some OS X 10.6 systems.

bpo-23345 [https://bugs.python.org/issue?@action=redirect&bpo=23345]: Prevent test_ssl failures with large OpenSSL patch level values (like 0.9.8zc).

Tools/Demos

bpo-22314 [https://bugs.python.org/issue?@action=redirect&bpo=22314]: pydoc now works when the LINES environment variable is set.

bpo-22615 [https://bugs.python.org/issue?@action=redirect&bpo=22615]: Argument Clinic now supports the “type” argument for the int converter. This permits using the int converter with enums and typedefs.

bpo-20076 [https://bugs.python.org/issue?@action=redirect&bpo=20076]: The makelocalealias.py script no longer ignores UTF-8 mapping.

bpo-20079 [https://bugs.python.org/issue?@action=redirect&bpo=20079]: The makelocalealias.py script now can parse the SUPPORTED file from glibc sources and supports command line options for source paths.

bpo-22201 [https://bugs.python.org/issue?@action=redirect&bpo=22201]: Command-line interface of the zipfile module now correctly extracts ZIP files with directory entries. Patch by Ryan Wilson.

bpo-22120 [https://bugs.python.org/issue?@action=redirect&bpo=22120]: For functions using an unsigned integer return converter, Argument Clinic now generates a cast to that type for the comparison to -1 in the generated code. (This suppresses a compilation warning.)

bpo-18974 [https://bugs.python.org/issue?@action=redirect&bpo=18974]: Tools/scripts/diff.py now uses argparse instead of optparse.

bpo-21906 [https://bugs.python.org/issue?@action=redirect&bpo=21906]: Make Tools/scripts/md5sum.py work in Python 3. Patch by Zachary Ware.

bpo-21629 [https://bugs.python.org/issue?@action=redirect&bpo=21629]: Fix Argument Clinic’s “–converters” feature.

Add support for yield from to 2to3.

Add support for the PEP 465 [https://peps.python.org/pep-0465/] matrix multiplication operator to 2to3.

bpo-16047 [https://bugs.python.org/issue?@action=redirect&bpo=16047]: Fix module exception list and __file__ handling in freeze. Patch by Meador Inge.

bpo-11824 [https://bugs.python.org/issue?@action=redirect&bpo=11824]: Consider ABI tags in freeze. Patch by Meador Inge.

bpo-20535 [https://bugs.python.org/issue?@action=redirect&bpo=20535]: PYTHONWARNING no longer affects the run_tests.py script. Patch by Arfrever Frehtes Taifersar Arahesis.

Windows

bpo-23260 [https://bugs.python.org/issue?@action=redirect&bpo=23260]: Update Windows installer

The bundled version of Tcl/Tk has been updated to 8.6.3. The most visible result of this change is the addition of new native file dialogs when running on Windows Vista or newer. See Tcl/Tk’s TIP 432 for more information. Also, this version of Tcl/Tk includes support for Windows 10.

bpo-17896 [https://bugs.python.org/issue?@action=redirect&bpo=17896]: The Windows build scripts now expect external library sources to be in PCbuild\..\externals rather than PCbuild\..\...

bpo-17717 [https://bugs.python.org/issue?@action=redirect&bpo=17717]: The Windows build scripts now use a copy of NASM pulled from svn.python.org to build OpenSSL.

bpo-21907 [https://bugs.python.org/issue?@action=redirect&bpo=21907]: Improved the batch scripts provided for building Python.

bpo-22644 [https://bugs.python.org/issue?@action=redirect&bpo=22644]: The bundled version of OpenSSL has been updated to 1.0.1j.

bpo-10747 [https://bugs.python.org/issue?@action=redirect&bpo=10747]: Use versioned labels in the Windows start menu. Patch by Olive Kilburn.

bpo-22980 [https://bugs.python.org/issue?@action=redirect&bpo=22980]: .pyd files with a version and platform tag (for example, “.cp35-win32.pyd”) will now be loaded in preference to those without tags.

(For information about older versions, consult the HISTORY file.)

파이썬 자습서

파이썬은 배우기 쉬우면서도 강력한 프로그래밍 언어입니다. 효율적인 자료 구조와 객체 지향 프로그래밍에 대한 간단하고도 효과적인 접근법을 제공합니다. 파이썬은 우아한 문법과 동적 타이핑(typing)을 지원하는 인터프리터 언어로서, 대부분 플랫폼과 다양한 문제 영역에서 스크립트 작성과 빠른 응용 프로그램 개발에 이상적인 환경을 제공합니다.

The Python interpreter and the extensive standard library are freely available in source or binary form for all major platforms from the Python web site, https://www.python.org/, and may be freely distributed. The same site also contains distributions of and pointers to many free third party Python modules, programs and tools, and additional documentation.

파이썬 인터프리터는 C 나 C++ (또는 C에서 호출 가능한 다른 언어들)로 구현된 새 함수나 자료 구조를 쉽게 추가할 수 있습니다. 파이썬은 고객화 가능한 응용 프로그램을 위한 확장 언어로도 적합합니다.

이 학습서는 파이썬 언어와 시스템의 기본 개념과 기능들을 격식 없이 소개합니다. 파이썬 인터프리터를 직접 만져볼 수 있도록 돕지만, 모든 예제가 독립적이기 때문에 오프라인에서 읽기에도 적합합니다.

표준 객체들과 모듈들에 대한 설명은 파이썬 표준 라이브러리 를 보세요. 파이썬 언어 레퍼런스 는 언어에 대한 좀 더 형식적인 정의를 제공합니다. C 나 C++ 로 확장하려면 파이썬 인터프리터 확장 및 내장 와 파이썬/C API 레퍼런스 설명서 를 읽으세요. 파이썬을 깊이 있게 다룬 책들도 많습니다.

이 자습서는 포괄적이려고 시도하지 않습니다. 모든 기능을 다루지는 않는데, 심지어 자주 사용되는 기능조차도 그렇습니다. 대신에, 파이썬의 가장 주목할만한 기능들을 소개하고, 언어의 맛과 스타일에 대한 전체적인 인상을 제공합니다. 이 학습서를 읽은 후에는 파이썬 모듈과 프로그램을 작성할 수 있고, 파이썬 표준 라이브러리 에 기술된 다양한 파이썬 라이브러리 모듈들에 대해 학습할 수 있는 준비가 될 것입니다.

용어집 또한 훑어볼 만한 가치가 있습니다.

1. 입맛 돋우기

2. 파이썬 인터프리터 사용하기

2.1. 인터프리터 실행하기

2.1.1. 인자 전달

2.1.2. 대화형 모드

2.2. 인터프리터와 환경

2.2.1. 소스 코드 인코딩

3. 파이썬의 간략한 소개

3.1. 파이썬을 계산기로 사용하기

3.1.1. 숫자

3.1.2. Text

3.1.3. 리스트

3.2. 프로그래밍으로의 첫걸음

4. 기타 제어 흐름 도구

4.1. if 문

4.2. for 문

4.3. range() 함수

4.4. break and continue Statements

4.5. else Clauses on Loops

4.6. pass 문

4.7. match Statements

4.8. 함수 정의하기

4.9. 함수 정의 더 보기

4.9.1. 기본 인자 값

4.9.2. 키워드 인자

4.9.3. 특수 매개 변수

4.9.3.1. 위치-키워드(Positional-or-Keyword) 인자

4.9.3.2. 위치 전용 매개 변수

4.9.3.3. 키워드 전용 인자

4.9.3.4. 함수 예제

4.9.3.5. 복습

4.9.4. 임의의 인자 목록

4.9.5. 인자 목록 언 패킹

4.9.6. 람다 표현식

4.9.7. 도큐멘테이션 문자열

4.9.8. 함수 어노테이션

4.10. 막간극: 코딩 스타일

5. 자료 구조

5.1. 리스트 더 보기

5.1.1. 리스트를 스택으로 사용하기

5.1.2. 리스트를 큐로 사용하기

5.1.3. 리스트 컴프리헨션

5.1.4. 중첩된 리스트 컴프리헨션

5.2. del 문

5.3. 튜플과 시퀀스

5.4. 집합

5.5. 딕셔너리

5.6. 루프 테크닉

5.7. 조건 더 보기

5.8. 시퀀스와 다른 형들을 비교하기

6. 모듈

6.1. 모듈 더 보기

6.1.1. 모듈을 스크립트로 실행하기

6.1.2. 모듈 검색 경로

6.1.3. “컴파일된” 파이썬 파일

6.2. 표준 모듈들

6.3. dir() 함수

6.4. 패키지

6.4.1. 패키지에서 * 임포트 하기

6.4.2. 패키지 내부 간의 참조

6.4.3. 여러 디렉터리에 있는 패키지

7. 입력과 출력

7.1. 장식적인 출력 포매팅

7.1.1. 포맷 문자열 리터럴

7.1.2. 문자열 format() 메서드

7.1.3. 수동 문자열 포매팅

7.1.4. 예전의 문자열 포매팅

7.2. 파일을 읽고 쓰기

7.2.1. 파일 객체의 매소드

7.2.2. json 으로 구조적인 데이터를 저장하기

8. 에러와 예외

8.1. 문법 에러

8.2. 예외

8.3. 예외 처리하기

8.4. 예외 일으키기

8.5. 예외 연쇄

8.6. 사용자 정의 예외

8.7. 뒷정리 동작 정의하기

8.8. 미리 정의된 뒷정리 동작들

8.9. Raising and Handling Multiple Unrelated Exceptions

8.10. Enriching Exceptions with Notes

9. 클래스

9.1. 이름과 객체에 관한 한마디

9.2. 파이썬 스코프와 이름 공간

9.2.1. 스코프와 이름 공간 예

9.3. 클래스와의 첫 만남

9.3.1. 클래스 정의 문법

9.3.2. 클래스 객체

9.3.3. 인스턴스 객체

9.3.4. 메서드 객체

9.3.5. 클래스와 인스턴스 변수

9.4. 기타 주의사항들

9.5. 상속

9.5.1. 다중 상속

9.6. 비공개 변수

9.7. 잡동사니

9.8. 이터레이터

9.9. 제너레이터

9.10. 제너레이터 표현식

10. 표준 라이브러리 둘러보기

10.1. 운영 체제 인터페이스

10.2. 파일 와일드카드

10.3. 명령행 인자

10.4. 에러 출력 리디렉션과 프로그램 종료

10.5. 문자열 패턴 매칭

10.6. 수학

10.7. 인터넷 액세스

10.8. 날짜와 시간

10.9. 데이터 압축

10.10. 성능 측정

10.11. 품질 관리

10.12. 배터리가 포함됩니다

11. 표준 라이브러리 둘러보기 — 2부

11.1. 출력 포매팅

11.2. 템플릿

11.3. 바이너리 데이터 레코드 배치 작업

11.4. 다중 스레딩

11.5. 로깅

11.6. 약한 참조

11.7. 리스트 작업 도구

11.8. Decimal Floating-Point Arithmetic

12. 가상 환경 및 패키지

12.1. 소개

12.2. 가상 환경 만들기

12.3. pip로 패키지 관리하기

13. 이제 뭘 하지?

14. 대화형 입력 편집 및 히스토리 치환

14.1. 탭 완성 및 히스토리 편집

14.2. 대화형 인터프리터 대안

15. Floating-Point Arithmetic: Issues and Limitations

15.1. 표현 오류

16. 부록

16.1. 대화형 모드

16.1.1. 에러 처리

16.1.2. 실행 가능한 파이썬 스크립트

16.1.3. 대화형 시작 파일

16.1.4. 커스터마이제이션 모듈

1. 입맛 돋우기

여러분이 컴퓨터를 많이 사용한다면, 결국 자동화하고 싶은 작업을 발견하게 됩니다. 예를 들어, 많은 텍스트 파일들을 검색-수정하고 싶거나, 사진 파일들을 복잡한 방법으로 이름을 바꾸거나 재배치하고 싶을 수 있습니다. 어쩌면 자그마한 자신만의 데이터베이스나 GUI 응용 프로그램, 또는 간단한 게임을 만들고 싶을 것입니다.

만약 여러분이 전문 소프트웨어 개발자라면, 여러 C/C++/Java 라이브러리들을 갖고 작업해야만 할 수 있는데, 일반적인 코드작성/컴파일/테스트/재컴파일 순환이 너무 느리다는 것을 깨닫게 됩니다. 어쩌면 그 라이브러리들을 위한 테스트 스위트를 작성하다가, 테스트 코드 작성에 따분해하는 자신을 발견하게 됩니다. 또는 확장 언어를 사용하는 프로그램을 작성했는데, 완전히 새로운 언어 전체를 설계하고 구현하고 싶지 않을 수 있습니다.

파이썬은 바로 여러분을 위한 언어입니다.

You could write a Unix shell script or Windows batch files for some of these tasks, but shell scripts are best at moving around files and changing text data, not well-suited for GUI applications or games. You could write a C/C++/Java program, but it can take a lot of development time to get even a first-draft program. Python is simpler to use, available on Windows, macOS, and Unix operating systems, and will help you get the job done more quickly.

파이썬은 사용이 간단하지만, 제대로 갖춰진 프로그래밍 언어인데, 셸 스크립트나 배치 파일보다 더 많은 구조를 제공하고 커다란 프로그램을 위한 지원을 제공합니다. 반면에, 파이썬은 C보다 훨씬 많은 에러 검사를 제공하고, 유연한 배열과 딕셔너리같은 고수준의 자료형들을 내장하고 있습니다. 더 일반적인 자료형들 때문에 Awk 나 Perl보다도 더 많은 문제영역에 쓸모가 있는데, 그러면서도 여전히 많은 것들이 적어도 이들 언어를 사용하는 것만큼 파이썬에서도 쉽게 해결할 수 있습니다.

파이썬은 여러분의 프로그램을 여러 모듈로 나눌 수 있도록 하는데, 각 모듈은 다른 파이썬 프로그램에서 재사용할 수 있습니다. 대규모의 표준 모듈들이 따라오는데 여러분의 프로그램 기초로 사용하거나 파이썬 프로그래밍을 배우기 위한 예제로 활용할 수 있습니다. 이 모듈에는 파일 입출력, 시스템 호출, 소켓들이 포함되는데, 심지어 Tk 와 같은 GUI 도구상자에 대한 인터페이스도 들어있습니다.

파이썬은 인터프리터 언어입니다. 컴파일과 링크 단계가 필요 없으므로 개발 시간을 상당히 단축해줍니다. 인터프리터는 대화형으로 사용할 수 있어서, 언어의 기능을 실험하거나, 쓰고 버릴 프로그램을 만들거나, 바닥부터 프로그램을 만들어가는 동안 함수들을 테스트하기 쉽습니다. 간편한 탁상용 계산기이기도 합니다.

파이썬은 간결하고 읽기 쉽게 프로그램을 작성할 수 있도록 합니다. 파이썬 프로그램은 여러 가지 이유로 같은 기능의 C, C++, Java 프로그램들에 비교해 간결합니다:

고수준의 자료형 때문에 복잡한 연산을 한 문장으로 표현할 수 있습니다;

문장의 묶음은 괄호 대신에 들여쓰기를 통해 이루어집니다;

변수나 인자의 선언이 필요 없다.

파이썬은 확장 가능 하다: C로 프로그램하는 법을 안다면, 인터프리터에 새로운 내장 함수나 자료형을 추가해서, 핵심 연산을 최대 속도로 수행하거나 바이너리 형태로만 제공되는 라이브러리(가령 업체가 제공하는 그래픽스 라이브러리)에 파이썬 프로그램을 연결할 수 있습니다. 진짜 파이썬에 매료되었다면, C로 만든 응용 프로그램에 파이썬 인터프리터를 연결하여 그 응용 프로그램의 확장이나 명령 언어로 사용할 수 있습니다.

파이썬 이라는 이름은 “Monty Python’s Flying Circus”라는 BBC 쇼에서 따온 것이고, 파충류와는 아무런 관련이 없습니다. 문서에서 Monty Python의 농담을 인용하는 것은 허락된 것일 뿐만 아니라, 권장되고 있습니다.

이제 여러분은 파이썬에 한껏 흥분한 상태고 좀 더 자세히 들여다보길 원할 것입니다. 언어를 배우는 가장 좋은 방법은 사용하는 것이기 때문에, 이 학습서를 읽으면서 직접 파이썬 인터프리터를 만져볼 것을 권합니다.

다음 장에서, 인터프리터를 사용하는 방법을 설명합니다. 이것은 약간 지루할 수도 있는 정보지만, 이후에 나오는 예제들을 실행하기 위해서는 꼭 필요합니다.

자습서의 나머지는 파이썬 언어와 시스템의 여러 기능을 예제를 통해 소개합니다. 간단한 표현식, 문장, 자료형에서 출발해서 함수와 모듈을 거쳐, 마지막으로 예외와 사용자 정의 클래스와 같은 고급 개념들을 다룹니다.

2. 파이썬 인터프리터 사용하기

2.1. 인터프리터 실행하기

The Python interpreter is usually installed as /usr/local/bin/python3.14 on those machines where it is available; putting /usr/local/bin in your Unix shell’s search path makes it possible to start it by typing the command:

python3.14

을 셸에 입력해서 실행할 수 있습니다. [1] 인터프리터가 위치하는 디렉터리의 선택은 설치 옵션이기 때문에, 다른 장소도 가능합니다; 주변의 파이썬 전문가나 시스템 관리자에게 확인할 필요가 있습니다. (예를 들어, /usr/local/python 도 널리 사용되는 위치입니다.)

On Windows machines where you have installed Python from the Microsoft Store, the python3.14 command will be available. If you have the py.exe launcher installed, you can use the py command. See 보충 설명: 환경 변수 설정하기 for other ways to launch Python.

기본 프롬프트에서 EOF(end-of-file) 문자(유닉스에서는 Control-D, 윈도우에서는 Control-Z)를 입력하면 인터프리터가 종료하고, 종료 상태 코드는 0 이 됩니다. 이 방법이 통하지 않는다면 quit() 명령을 입력해서 인터프리터를 종료시킬 수 있습니다.

인터프리터는 GNU Readline [https://tiswww.case.edu/php/chet/readline/rltop.html] 라이브러리를 지원하는 시스템에서 줄 편집 기능으로 대화형 편집, 히스토리 치환, 코드 완성 등을 제공합니다. 아마도 명령행 편집이 제공되는지 확인하는 가장 빠른 방법은 첫 프롬프트에서 Control-P 를 입력하는 것입니다. 삑 하는 소리가 난다면 명령행 편집이 지원되고 있습니다; 입력 키에 대한 소개는 부록 대화형 입력 편집 및 히스토리 치환 을 보세요. 아무런 반응도 없거나 ^P 가 출력된다면 명령행 편집이 제공되지 않는 것입니다; 현재 줄에서 문자를 지우기 위해 백스페이스를 사용할 수 있는 것이 전부입니다.

인터프리터는 어느 정도 유닉스 셸처럼 동작합니다: tty 장치에 표준 입력이 연결된 상태로 실행되면, 대화형으로 명령을 읽고 실행합니다; 파일명을 인자로 주거나 파일을 표준입력으로 연결한 상태로 실행되면 스크립트를 읽고 실행합니다.

A second way of starting the interpreter is python -c command [arg] ..., which executes the statement(s) in command, analogous to the shell’s -c option. Since Python statements often contain spaces or other characters that are special to the shell, it is usually advised to quote command in its entirety.

몇몇 파이썬 모듈들은 스크립트로도 쓸모가 있습니다. python -m module [arg] ... 로 실행할 수 있는데, 마치 module 모듈 소스 파일의 경로명을 명령행에 입력한 것처럼 실행되게 됩니다.

스크립트 파일이 사용될 때, 때로 스크립트를 실행한 후에 대화형 모드로 들어가는 것이 편리할 때가 있습니다. 스크립트 앞에 -i 를 전달하면 됩니다.

모든 명령행 옵션은 명령 줄과 환경 에서 찾을 수 있습니다.

2.1.1. 인자 전달

스크립트 이름과 추가의 인자들이 인터프리터로 전달될 때, 문자열의 목록으로 변환된 후 sys 모듈의 argv 변수에 저장됩니다. import sys 를 사용해서 이 목록에 접근할 수 있습니다. 목록의 길이는 최소한 1이고, 스크립트도 추가의 인자도 없는 경우로, sys.argv[0] 은 빈 문자열입니다. 스크립트 이름을 '-' (표준 입력을 뜻한다) 로 주면 sys.argv[0] 는 '-' 가 됩니다. -c command 가 사용되면 sys.argv[0] 는 '-c' 로 설정됩니다. -m module 이 사용되면 sys.argv[0] 는 모듈의 절대 경로명이 됩니다. -c command 나 -m module 뒤에 오는 옵션들은 파이썬 인터프리터가 소모하지 않고 명령이나 모듈이 처리하도록 sys.argv 로 전달됩니다.

2.1.2. 대화형 모드

명령을 tty 에서 읽을 때, 인터프리터가 대화형 모드 로 동작한다고 말합니다. 이 모드에서는 기본 프롬프트 를 표시해서 다음 명령을 요청하는데, 보통 세 개의 …보다 크다 기호입니다 (>>>); 한 줄로 끝나지 않고 이어지는 줄의 입력을 요청할 때는 보조 프롬프트가 사용되는데, 기본적으로 세 개의 점입니다 (...). 인터프리터는 첫 번째 프롬프트를 인쇄하기 전에 버전 번호와 저작권 공지를 포함하는 환영 메시지를 출력합니다.

$ python3.14
Python 3.14 (default, April 4 2024, 09:25:04)
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

이어지는 줄은 여러 줄로 구성된 구조물을 입력할 때 필요합니다. 예를 들자면, 이런 식의 if 문이 가능합니다:

>>> the_world_is_flat = True
>>> if the_world_is_flat:
...     print("Be careful not to fall off!")
...
Be careful not to fall off!

대화형 모드에 대해 더 알고 싶다면, 대화형 모드 를 보세요.

2.2. 인터프리터와 환경

2.2.1. 소스 코드 인코딩

기본적으로, 파이썬 소스 파일들은 UTF-8으로 인코드 된 것으로 취급됩니다. 이 인코딩에서는 대부분 언어에서 사용되는 문자들을 문자열 상수, 식별자, 주석 등에서 함께 사용할 수 있습니다. (하지만 표준 라이브러리는 오직 ASCII 문자만 식별자로 사용하고 있는데, 범용 코드에서는 이 관례를 따르는 것이 좋습니다.) 이 문자들을 모두 올바로 표시하기 위해서는 편집기가 파일이 UTF-8임을 인식해야 하고, 이 파일에 포함된 모든 문자를 지원할 수 있는 글꼴을 사용해야 합니다.

인코딩을 기본값 외의 것으로 선언하려면, 파일의 첫 줄에 특별한 형태의 주석 문을 추가해야 합니다. 문법은 이렇습니다:

# -*- coding: encoding -*-

encoding 은 파이썬이 지원하는 코덱 (codecs) 중 하나여야 합니다.

예를 들어, Windows-1252 인코딩을 사용하도록 선언하려면, 소스 코드 파일의 첫 줄은 이렇게 되어야 합니다:

# -*- coding: cp1252 -*-

첫 줄 규칙의 한가지 예외는 소스 코드가 유닉스 “셔뱅 (shebang)” 줄 로 시작하는 경우입니다. 이 경우에, 인코딩 선언은 두 번째 줄에 들어갑니다. 예를 들어:

#!/usr/bin/env python3
# -*- coding: cp1252 -*-

각주

[1]

유닉스에서, 파이썬 3.x 인터프리터는 보통 python 이라는 이름의 실행 파일로 설치되지 않는데, 동시에 설치되는 파이썬 2.x 실행 파일과 충돌하지 않도록 하기 위해섭니다.

3. 파이썬의 간략한 소개

다음에 나올 예에서, 입력과 출력은 프롬프트(>>> 와 …)의 존재 여부로 구분됩니다: 예제를 실행하기 위해서는 프롬프트가 나올 때 프롬프트 뒤에 오는 모든 것들을 입력해야 합니다; 프롬프트로 시작하지 않는 줄들은 인터프리터가 출력하는 것들입니다. 예에서 보조 프롬프트 외에 아무것도 없는 줄은 빈 줄을 입력해야 한다는 뜻임에 주의하세요; 여러 줄로 구성된 명령을 끝내는 방법입니다.

You can toggle the display of prompts and output by clicking on >>> in the upper-right corner of an example box. If you hide the prompts and output for an example, then you can easily copy and paste the input lines into your interpreter.

이 설명서에 나오는 많은 예는 (대화형 프롬프트에서 입력되는 것들조차도) 주석을 포함하고 있습니다. 파이썬에서 주석은 해시 문자, #, 로 시작하고 줄의 끝까지 이어집니다. 주석은 줄의 처음에서 시작할 수도 있고, 공백이나 코드 뒤에 나올 수도 있습니다. 하지만 문자열 리터럴 안에는 들어갈 수 없습니다. 문자열 리터럴 안에 등장하는 해시 문자는 주석이 아니라 해시 문자일 뿐입니다. 주석은 코드의 의미를 정확히 전달하기 위한 것이고, 파이썬이 해석하지 않는 만큼, 예를 입력할 때는 생략해도 됩니다.

몇 가지 예를 듭니다:

# this is the first comment
spam = 1  # and this is the second comment
          # ... and now a third!
text = "# This is not a comment because it's inside quotes."

3.1. 파이썬을 계산기로 사용하기

몇 가지 간단한 파이썬 명령을 사용해봅시다. 인터프리터를 실행하고 기본 프롬프트, >>>, 를 기다리세요. (얼마 걸리지 않아야 합니다.)

3.1.1. 숫자

The interpreter acts as a simple calculator: you can type an expression at it and it will write the value. Expression syntax is straightforward: the operators +, -, * and / can be used to perform arithmetic; parentheses (()) can be used for grouping. For example:

>>> 2 + 2
4
>>> 50 - 5*6
20
>>> (50 - 5*6) / 4
5.0
>>> 8 / 5  # division always returns a floating-point number
1.6

정수 (예를 들어 2, 4, 20)는 int 형입니다. 소수부가 있는 것들 (예를 들어 5.0, 1.6)은 float 형입니다. 이 자습서 뒤에서 숫자 형들에 관해 더 자세히 살펴볼 예정입니다.

Division (/) always returns a float. To do floor division and get an integer result you can use the // operator; to calculate the remainder you can use %:

>>> 17 / 3  # classic division returns a float
5.666666666666667
>>>
>>> 17 // 3  # floor division discards the fractional part
5
>>> 17 % 3  # the % operator returns the remainder of the division
2
>>> 5 * 3 + 2  # floored quotient * divisor + remainder
17

파이썬에서는 거듭제곱을 계산할 때 ** 연산자를 사용합니다 [1]:

>>> 5 ** 2  # 5 squared
25
>>> 2 ** 7  # 2 to the power of 7
128

변수에 값을 대입할 때는 등호(=)를 사용합니다. 이 경우 다음 대화형 프롬프트 전에 표시되는 출력은 없습니다:

>>> width = 20
>>> height = 5 * 9
>>> width * height
900

변수가 “정의되어” 있지 않을 때 (값을 대입하지 않았을 때) 사용하려고 시도하는 것은 에러를 일으킵니다:

>>> n  # try to access an undefined variable
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'n' is not defined

실수를 본격적으로 지원합니다; 서로 다른 형의 피연산자를 갖는 연산자는 정수 피연산자를 실수로 변환합니다:

>>> 4 * 3.75 - 1
14.0

대화형 모드에서는, 마지막에 인쇄된 표현식은 변수 _ 에 대입됩니다. 이것은 파이썬을 탁상용 계산기로 사용할 때, 계산을 이어 가기가 좀 더 쉬워짐을 의미합니다. 예를 들어:

>>> tax = 12.5 / 100
>>> price = 100.50
>>> price * tax
12.5625
>>> price + _
113.0625
>>> round(_, 2)
113.06

이 변수는 사용자로서는 읽기만 가능한 것처럼 취급되어야 합니다. 값을 직접 대입하지 마세요 — 만약 그렇게 한다면 같은 이름의 지역 변수를 새로 만드는 것이 되는데, 내장 변수의 마술 같은 동작을 차단하는 결과를 낳습니다.

int 와 float 에 더해, 파이썬은 Decimal 이나 Fraction 등의 다른 형의 숫자들도 지원합니다. 파이썬은 복소수 에 대한 지원도 내장하고 있는데, 허수부를 가리키는데 j 나 J 접미사를 사용합니다 (예를 들어 3+5j).

3.1.2. Text

Python can manipulate text (represented by type str, so-called “strings”) as well as numbers. This includes characters “!”, words “rabbit”, names “Paris”, sentences “Got your back.”, etc. “Yay! :)”. They can be enclosed in single quotes ('...') or double quotes ("...") with the same result [2].

>>> 'spam eggs'  # single quotes
'spam eggs'
>>> "Paris rabbit got your back :)! Yay!"  # double quotes
'Paris rabbit got your back :)! Yay!'
>>> '1975'  # digits and numerals enclosed in quotes are also strings
'1975'

To quote a quote, we need to “escape” it, by preceding it with \. Alternatively, we can use the other type of quotation marks:

>>> 'doesn\'t'  # use \' to escape the single quote...
"doesn't"
>>> "doesn't"  # ...or use double quotes instead
"doesn't"
>>> '"Yes," they said.'
'"Yes," they said.'
>>> "\"Yes,\" they said."
'"Yes," they said.'
>>> '"Isn\'t," they said.'
'"Isn\'t," they said.'

In the Python shell, the string definition and output string can look different. The print() function produces a more readable output, by omitting the enclosing quotes and by printing escaped and special characters:

>>> s = 'First line.\nSecond line.'  # \n means newline
>>> s  # without print(), special characters are included in the string
'First line.\nSecond line.'
>>> print(s)  # with print(), special characters are interpreted, so \n produces new line
First line.
Second line.

\ 뒤에 나오는 문자가 특수 문자로 취급되게 하고 싶지 않다면, 첫 따옴표 앞에 r 을 붙여서 날 문자열 (raw string) 을 만들 수 있습니다:

>>> print('C:\some\name')  # here \n means newline!
C:\some
ame
>>> print(r'C:\some\name')  # note the r before the quote
C:\some\name

There is one subtle aspect to raw strings: a raw string may not end in an odd number of \ characters; see the FAQ entry for more information and workarounds.

String literals can span multiple lines. One way is using triple-quotes: """...""" or '''...'''. End of lines are automatically included in the string, but it’s possible to prevent this by adding a \ at the end of the line. In the following example, the initial newline is not included:

>>> print("""\
... Usage: thingy [OPTIONS]
...      -h                        Display this usage message
...      -H hostname               Hostname to connect to
... """)
Usage: thingy [OPTIONS]
     -h                        Display this usage message
     -H hostname               Hostname to connect to

>>>

문자열은 + 연산자로 이어붙이고, * 연산자로 반복시킬 수 있습니다:

>>> # 3 times 'un', followed by 'ium'
>>> 3 * 'un' + 'ium'
'unununium'

두 개 이상의 문자열 리터럴 (즉, 따옴표로 둘러싸인 것들) 가 연속해서 나타나면 자동으로 이어 붙여집니다.

>>> 'Py' 'thon'
'Python'

이 기능은 긴 문자열을 쪼개고자 할 때 특별히 쓸모 있습니다:

>>> text = ('Put several strings within parentheses '
...         'to have them joined together.')
>>> text
'Put several strings within parentheses to have them joined together.'

이것은 오직 두 개의 리터럴에만 적용될 뿐 변수나 표현식에는 해당하지 않습니다:

>>> prefix = 'Py'
>>> prefix 'thon'  # can't concatenate a variable and a string literal
  File "<stdin>", line 1
    prefix 'thon'
           ^^^^^^
SyntaxError: invalid syntax
>>> ('un' * 3) 'ium'
  File "<stdin>", line 1
    ('un' * 3) 'ium'
               ^^^^^
SyntaxError: invalid syntax

변수들끼리 혹은 변수와 문자열 리터럴을 이어붙이려면 + 를 사용해야 합니다

>>> prefix + 'thon'
'Python'

문자열은 인덱스 (서브 스크립트) 될 수 있습니다. 첫 번째 문자가 인덱스 0에 대응됩니다. 문자를 위한 별도의 형은 없습니다; 단순히 길이가 1인 문자열입니다:

>>> word = 'Python'
>>> word[0]  # character in position 0
'P'
>>> word[5]  # character in position 5
'n'

인덱스는 음수가 될 수도 있는데, 끝에서부터 셉니다:

>>> word[-1]  # last character
'n'
>>> word[-2]  # second-last character
'o'
>>> word[-6]
'P'

-0은 0과 같으므로, 음의 인덱스는 -1에서 시작한다는 것에 주목하세요.

In addition to indexing, slicing is also supported. While indexing is used to obtain individual characters, slicing allows you to obtain a substring:

>>> word[0:2]  # characters from position 0 (included) to 2 (excluded)
'Py'
>>> word[2:5]  # characters from position 2 (included) to 5 (excluded)
'tho'

슬라이스 인덱스는 편리한 기본값을 갖고 있습니다; 첫 번째 인덱스를 생략하면 기본값 0 이 사용되고, 두 번째 인덱스가 생략되면 기본값으로 슬라이싱 되는 문자열의 길이가 사용됩니다.

>>> word[:2]   # character from the beginning to position 2 (excluded)
'Py'
>>> word[4:]   # characters from position 4 (included) to the end
'on'
>>> word[-2:]  # characters from the second-last (included) to the end
'on'

시작 위치의 문자는 항상 포함되는 반면, 종료 위치의 문자는 항상 포함되지 않는 것에 주의하세요. 이 때문에 s[:i] + s[i:] 는 항상 s 와 같아집니다

>>> word[:2] + word[2:]
'Python'
>>> word[:4] + word[4:]
'Python'

슬라이스가 동작하는 방법을 기억하는 한 가지 방법은 인덱스가 문자들 사이의 위치를 가리킨다고 생각하는 것입니다. 첫 번째 문자의 왼쪽 경계가 0입니다. n 개의 문자들로 구성된 문자열의 오른쪽 끝 경계는 인덱스 n 이 됩니다, 예를 들어:

 +---+---+---+---+---+---+
 | P | y | t | h | o | n |
 +---+---+---+---+---+---+
 0   1   2   3   4   5   6
-6  -5  -4  -3  -2  -1

첫 번째 숫자 행은 인덱스 0…6 의 위치를 보여주고; 두 번째 행은 대응하는 음의 인덱스들을 보여줍니다. i 에서 j 범위의 슬라이스는 i 와 j 로 번호 붙여진 경계 사이의 문자들로 구성됩니다.

음이 아닌 인덱스들의 경우, 두 인덱스 모두 범위 내에 있다면 슬라이스의 길이는 인덱스 간의 차입니다. 예를 들어 word[1:3] 의 길이는 2입니다.

너무 큰 값을 인덱스로 사용하는 것은 에러입니다:

>>> word[42]  # the word only has 6 characters
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: string index out of range

하지만, 범위를 벗어나는 슬라이스 인덱스는 슬라이싱할 때 부드럽게 처리됩니다:

>>> word[4:42]
'on'
>>> word[42:]
''

파이썬 문자열은 변경할 수 없다 — 불변 이라고 합니다. 그래서 문자열의 인덱스로 참조한 위치에 대입하려고 하면 에러를 일으킵니다:

>>> word[0] = 'J'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment
>>> word[2:] = 'py'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment

다른 문자열이 필요하면, 새로 만들어야 합니다:

>>> 'J' + word[1:]
'Jython'
>>> word[:2] + 'py'
'Pypy'

내장 함수 len() 은 문자열의 길이를 돌려줍니다:

>>> s = 'supercalifragilisticexpialidocious'
>>> len(s)
34

더 보기

텍스트 시퀀스 형 — str

문자열은 시퀀스 형 의 일종이고, 시퀀스가 지원하는 공통 연산들이 지원됩니다.

문자열 메서드

문자열은 기본적인 변환과 검색을 위한 여러 가지 메서드들을 지원합니다.

f-strings

내장된 표현식을 갖는 문자열 리터럴

포맷 문자열 문법

str.format() 으로 문자열을 포맷하는 방법에 대한 정보.

printf 스타일 문자열 포매팅

이곳에서 문자열을 % 연산자 왼쪽에 사용하는 예전 방식의 포매팅에 관해 좀 더 상세하게 설명하고 있습니다.

3.1.3. 리스트

파이썬은 다른 값들을 덩어리로 묶는데 사용되는 여러 가지 컴파운드 (compound) 자료 형을 알고 있습니다. 가장 융통성이 있는 것은 리스트 인데, 대괄호 사이에 쉼표로 구분된 값(항목)들의 목록으로 표현될 수 있습니다. 리스트는 서로 다른 형의 항목들을 포함할 수 있지만, 항목들이 모두 같은 형인 경우가 많습니다.

>>> squares = [1, 4, 9, 16, 25]
>>> squares
[1, 4, 9, 16, 25]

문자열(그리고, 다른 모든 내장 시퀀스 형들)처럼 리스트는 인덱싱하고 슬라이싱할 수 있습니다:

>>> squares[0]  # indexing returns the item
1
>>> squares[-1]
25
>>> squares[-3:]  # slicing returns a new list
[9, 16, 25]

리스트는 이어붙이기 같은 연산도 지원합니다:

>>> squares + [36, 49, 64, 81, 100]
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

불변 인 문자열과는 달리, 리스트는 가변 입니다. 즉 내용을 변경할 수 있습니다:

>>> cubes = [1, 8, 27, 65, 125]  # something's wrong here
>>> 4 ** 3  # the cube of 4 is 64, not 65!
64
>>> cubes[3] = 64  # replace the wrong value
>>> cubes
[1, 8, 27, 64, 125]

You can also add new items at the end of the list, by using the list.append() method (we will see more about methods later):

>>> cubes.append(216)  # add the cube of 6
>>> cubes.append(7 ** 3)  # and the cube of 7
>>> cubes
[1, 8, 27, 64, 125, 216, 343]

Simple assignment in Python never copies data. When you assign a list to a variable, the variable refers to the existing list. Any changes you make to the list through one variable will be seen through all other variables that refer to it.:

>>> rgb = ["Red", "Green", "Blue"]
>>> rgba = rgb
>>> id(rgb) == id(rgba)  # they reference the same object
True
>>> rgba.append("Alph")
>>> rgb
["Red", "Green", "Blue", "Alph"]

모든 슬라이스 연산은 요청한 항목들을 포함하는 새 리스트를 돌려줍니다. 이는 다음과 같은 슬라이스가 리스트의 새로운 얕은 복사본을 돌려준다는 뜻입니다:

>>> correct_rgba = rgba[:]
>>> correct_rgba[-1] = "Alpha"
>>> correct_rgba
["Red", "Green", "Blue", "Alpha"]
>>> rgba
["Red", "Green", "Blue", "Alph"]

슬라이스에 대입하는 것도 가능한데, 리스트의 길이를 변경할 수 있고, 모든 항목을 삭제할 수조차 있습니다:

>>> letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
>>> letters
['a', 'b', 'c', 'd', 'e', 'f', 'g']
>>> # replace some values
>>> letters[2:5] = ['C', 'D', 'E']
>>> letters
['a', 'b', 'C', 'D', 'E', 'f', 'g']
>>> # now remove them
>>> letters[2:5] = []
>>> letters
['a', 'b', 'f', 'g']
>>> # clear the list by replacing all the elements with an empty list
>>> letters[:] = []
>>> letters
[]

내장 함수 len() 은 리스트에도 적용됩니다:

>>> letters = ['a', 'b', 'c', 'd']
>>> len(letters)
4

리스트를 중첩할 수도 있습니다. (다른 리스트를 포함하는 리스트를 만듭니다). 예를 들어:

>>> a = ['a', 'b', 'c']
>>> n = [1, 2, 3]
>>> x = [a, n]
>>> x
[['a', 'b', 'c'], [1, 2, 3]]
>>> x[0]
['a', 'b', 'c']
>>> x[0][1]
'b'

3.2. 프로그래밍으로의 첫걸음

Of course, we can use Python for more complicated tasks than adding two and two together. For instance, we can write an initial sub-sequence of the Fibonacci series [https://en.wikipedia.org/wiki/Fibonacci_sequence] as follows:

>>> # Fibonacci series:
>>> # the sum of two elements defines the next
>>> a, b = 0, 1
>>> while a < 10:
...     print(a)
...     a, b = b, a+b
...
0
1
1
2
3
5
8

이 예는 몇 가지 새로운 기능을 소개하고 있습니다.

첫 줄은 다중 대입 을 포함하고 있습니다: 변수 a 와 b 에 동시에 값 0과1이 대입됩니다. 마지막 줄에서 다시 사용되는데, 대입이 어느 하나라도 이루어지기 전에 우변의 표현식들이 모두 계산됩니다. 우변의 표현식은 왼쪽부터 오른쪽으로 가면서 순서대로 계산됩니다.

while 루프는 조건(여기서는: a < 10)이 참인 동안 실행됩니다. C와 마찬가지로 파이썬에서 0 이 아닌 모든 정수는 참이고, 0은 거짓입니다. 조건은 문자열이나 리스트 (사실 모든 종류의 시퀀스)가 될 수도 있는데 길이가 0 이 아닌 것은 모두 참이고, 빈 시퀀스는 거짓입니다. 이 예에서 사용한 검사는 간단한 비교입니다. 표준 비교 연산자는 C와 같은 방식으로 표현됩니다: < (작다), > (크다), == (같다), <= (작거나 같다), >= (크거나 같다), != (다르다).

루프의 바디 (body) 는 들여쓰기 됩니다. 들여쓰기는 파이썬에서 문장을 덩어리로 묶는 방법입니다. 대화형 프롬프트에서 각각 들여 쓰는 줄에서 탭(tab)이나 공백(space)을 입력해야 합니다. 실제적으로는 텍스트 편집기를 사용해서 좀 더 복잡한 파이썬 코드를 준비하게 됩니다; 웬만한 텍스트 편집기들은 자동 들여쓰기 기능을 제공합니다. 복합문을 대화형으로 입력할 때는 끝을 알리기 위해 빈 줄을 입력해야 합니다. (해석기가 언제 마지막 줄을 입력할지 짐작할 수 없기 때문입니다.) 같은 블록에 포함되는 모든 줄은 같은 양만큼 들여쓰기 되어야 함에 주의하세요.

The print() function writes the value of the argument(s) it is given. It differs from just writing the expression you want to write (as we did earlier in the calculator examples) in the way it handles multiple arguments, floating-point quantities, and strings. Strings are printed without quotes, and a space is inserted between items, so you can format things nicely, like this:

>>> i = 256*256
>>> print('The value of i is', i)
The value of i is 65536

키워드 인자 end 는 출력 끝에 포함되는 개행문자를 제거하거나 출력을 다른 문자열로 끝나게 하고 싶을 때 사용됩니다:

>>> a, b = 0, 1
>>> while a < 1000:
...     print(a, end=',')
...     a, b = b, a+b
...
0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,

각주

[1]

** 가 - 보다 우선순위가 높으므로, -3**2 는 -(3**2) 로 해석되어서 결과는 -9 가 됩니다. 9 를 얻고 싶으면 (-3)**2 를 사용할 수 있습니다.

[2]

다른 언어들과는 달리, \n 과 같은 특수 문자들은 작은따옴표('...')와 큰따옴표("...")에서 같은 의미가 있습니다. 둘 간의 유일한 차이는 작은따옴표 안에서 " 를 이스케이핑할 필요가 없고 (하지만 \' 는 이스케이핑 시켜야 합니다), 그 역도 성립한다는 것입니다.

4. 기타 제어 흐름 도구

As well as the while statement just introduced, Python uses a few more that we will encounter in this chapter.

4.1. if 문

아마도 가장 잘 알려진 문장 형은 if 문일 것입니다. 예를 들어:

>>> x = int(input("Please enter an integer: "))
Please enter an integer: 42
>>> if x < 0:
...     x = 0
...     print('Negative changed to zero')
... elif x == 0:
...     print('Zero')
... elif x == 1:
...     print('Single')
... else:
...     print('More')
...
More

없거나 여러 개의 elif 부가 있을 수 있고, else 부는 선택적입니다. 키워드 ‘elif’ 는 ‘else if’ 의 줄임 표현인데, 과도한 들여쓰기를 피하는 데 유용합니다. if … elif … elif … 시퀀스는 다른 언어들에서 발견되는 switch 나 case 문을 대신합니다.

If you’re comparing the same value to several constants, or checking for specific types or attributes, you may also find the match statement useful. For more details see match Statements.

4.2. for 문

파이썬에서 for 문은 C 나 파스칼에서 사용하던 것과 약간 다릅니다. (파스칼처럼) 항상 숫자의 산술적인 진행을 통해 이터레이션 하거나, (C처럼) 사용자가 이터레이션 단계와 중지 조건을 정의할 수 있도록 하는 대신, 파이썬의 for 문은 임의의 시퀀스 (리스트나 문자열)의 항목들을 그 시퀀스에 들어있는 순서대로 이터레이션 합니다. 예를 들어 (말장난이 아니라):

>>> # Measure some strings:
>>> words = ['cat', 'window', 'defenestrate']
>>> for w in words:
...     print(w, len(w))
...
cat 3
window 6
defenestrate 12

컬렉션을 이터레이트 하는 동안 같은 컬렉션을 수정하는 코드는 올바르게 동작하도록 만들기 힘듭니다. 대신, 보통 컬렉션의 복사본으로 루프를 만들거나 새 컬렉션을 만드는 것이 더 간단합니다:

# Create a sample collection
users = {'Hans': 'active', 'Éléonore': 'inactive', '景太郎': 'active'}

# Strategy:  Iterate over a copy
for user, status in users.copy().items():
    if status == 'inactive':
        del users[user]

# Strategy:  Create a new collection
active_users = {}
for user, status in users.items():
    if status == 'active':
        active_users[user] = status

4.3. range() 함수

숫자들의 시퀀스로 이터레이트할 필요가 있으면, 내장 함수 range()가 편리합니다. 수열을 만듭니다:

>>> for i in range(5):
...     print(i)
...
0
1
2
3
4

끝값은 만들어지는 수열에 포함되지 않습니다; range(10) 은 10개의 값을 만드는데, 길이 10인 시퀀스의 항목들을 가리키는 올바른 인덱스들입니다. 범위가 다른 숫자로 시작하거나, 다른 증가분을 (음수조차 가능합니다; 때로 이것을 ‘스텝(step)’이라고 부릅니다) 지정하는 것도 가능합니다:

>>> list(range(5, 10))
[5, 6, 7, 8, 9]

>>> list(range(0, 10, 3))
[0, 3, 6, 9]

>>> list(range(-10, -100, -30))
[-10, -40, -70]

시퀀스의 인덱스들로 이터레이트 하려면, 다음처럼 range()와 len() 을 결합할 수 있습니다:

>>> a = ['Mary', 'had', 'a', 'little', 'lamb']
>>> for i in range(len(a)):
...     print(i, a[i])
...
0 Mary
1 had
2 a
3 little
4 lamb

하지만, 그럴 때 대부분은, enumerate() 함수를 쓰는 것이 편리합니다, 루프 테크닉 를 보세요.

범위를 그냥 인쇄하면 이상한 일이 일어납니다:

>>> range(10)
range(0, 10)

많은 경우에 range()가 돌려준 객체는 리스트인 것처럼 동작하지만, 사실 리스트가 아닙니다. 이터레이트할 때 원하는 시퀀스 항목들을 순서대로 돌려주는 객체이지만, 실제로 리스트를 만들지 않아서 공간을 절약합니다.

이런 객체를 이터러블 이라고 부릅니다. 공급이 소진될 때까지 일련의 항목들을 얻을 수 있는 무엇인가를 기대하는 함수와 구조물들의 타깃으로 적합합니다. 우리는 for 문이 그런 구조물임을 보았습니다. 이터러블을 취하는 함수의 예는 sum()입니다:

>>> sum(range(4))  # 0 + 1 + 2 + 3
6

Later we will see more functions that return iterables and take iterables as arguments. In chapter 자료 구조, we will discuss in more detail about list().

4.4. break and continue Statements

The break statement breaks out of the innermost enclosing for or while loop:

>>> for n in range(2, 10):
...     for x in range(2, n):
...         if n % x == 0:
...             print(f"{n} equals {x} * {n//x}")
...             break
...
4 equals 2 * 2
6 equals 2 * 3
8 equals 2 * 4
9 equals 3 * 3

The continue statement continues with the next iteration of the loop:

>>> for num in range(2, 10):
...     if num % 2 == 0:
...         print(f"Found an even number {num}")
...         continue
...     print(f"Found an odd number {num}")
...
Found an even number 2
Found an odd number 3
Found an even number 4
Found an odd number 5
Found an even number 6
Found an odd number 7
Found an even number 8
Found an odd number 9

4.5. else Clauses on Loops

In a for or while loop the break statement may be paired with an else clause. If the loop finishes without executing the break, the else clause executes.

In a for loop, the else clause is executed after the loop finishes its final iteration, that is, if no break occurred.

In a while loop, it’s executed after the loop’s condition becomes false.

In either kind of loop, the else clause is not executed if the loop was terminated by a break. Of course, other ways of ending the loop early, such as a return or a raised exception, will also skip execution of the else clause.

This is exemplified in the following for loop, which searches for prime numbers:

>>> for n in range(2, 10):
...     for x in range(2, n):
...         if n % x == 0:
...             print(n, 'equals', x, '*', n//x)
...             break
...     else:
...         # loop fell through without finding a factor
...         print(n, 'is a prime number')
...
2 is a prime number
3 is a prime number
4 equals 2 * 2
5 is a prime number
6 equals 2 * 3
7 is a prime number
8 equals 2 * 4
9 equals 3 * 3

(Yes, this is the correct code. Look closely: the else clause belongs to the for loop, not the if statement.)

One way to think of the else clause is to imagine it paired with the if inside the loop. As the loop executes, it will run a sequence like if/if/if/else. The if is inside the loop, encountered a number of times. If the condition is ever true, a break will happen. If the condition is never true, the else clause outside the loop will execute.

When used with a loop, the else clause has more in common with the else clause of a try statement than it does with that of if statements: a try statement’s else clause runs when no exception occurs, and a loop’s else clause runs when no break occurs. For more on the try statement and exceptions, see 예외 처리하기.

4.6. pass 문

pass 문은 아무것도 하지 않습니다. 문법적으로 문장이 필요하지만, 프로그램이 특별히 할 일이 없을 때 사용할 수 있습니다. 예를 들어:

>>> while True:
...     pass  # Busy-wait for keyboard interrupt (Ctrl+C)
...

최소한의 클래스를 만들 때 흔히 사용됩니다:

>>> class MyEmptyClass:
...     pass
...

pass가 사용될 수 있는 다른 장소는 새 코드를 작업할 때 함수나 조건부 바디의 자리를 채우는 것인데, 여러분이 더 추상적인 수준에서 생각할 수 있게 합니다. pass 는 조용히 무시됩니다:

>>> def initlog(*args):
...     pass   # Remember to implement this!
...

4.7. match Statements

A match statement takes an expression and compares its value to successive patterns given as one or more case blocks. This is superficially similar to a switch statement in C, Java or JavaScript (and many other languages), but it’s more similar to pattern matching in languages like Rust or Haskell. Only the first pattern that matches gets executed and it can also extract components (sequence elements or object attributes) from the value into variables.

The simplest form compares a subject value against one or more literals:

def http_error(status):
    match status:
        case 400:
            return "Bad request"
        case 404:
            return "Not found"
        case 418:
            return "I'm a teapot"
        case _:
            return "Something's wrong with the internet"

Note the last block: the “variable name” _ acts as a wildcard and never fails to match. If no case matches, none of the branches is executed.

You can combine several literals in a single pattern using | (“or”):

case 401 | 403 | 404:
    return "Not allowed"

Patterns can look like unpacking assignments, and can be used to bind variables:

# point is an (x, y) tuple
match point:
    case (0, 0):
        print("Origin")
    case (0, y):
        print(f"Y={y}")
    case (x, 0):
        print(f"X={x}")
    case (x, y):
        print(f"X={x}, Y={y}")
    case _:
        raise ValueError("Not a point")

Study that one carefully! The first pattern has two literals, and can be thought of as an extension of the literal pattern shown above. But the next two patterns combine a literal and a variable, and the variable binds a value from the subject (point). The fourth pattern captures two values, which makes it conceptually similar to the unpacking assignment (x, y) = point.

If you are using classes to structure your data you can use the class name followed by an argument list resembling a constructor, but with the ability to capture attributes into variables:

class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

def where_is(point):
    match point:
        case Point(x=0, y=0):
            print("Origin")
        case Point(x=0, y=y):
            print(f"Y={y}")
        case Point(x=x, y=0):
            print(f"X={x}")
        case Point():
            print("Somewhere else")
        case _:
            print("Not a point")

You can use positional parameters with some builtin classes that provide an ordering for their attributes (e.g. dataclasses). You can also define a specific position for attributes in patterns by setting the __match_args__ special attribute in your classes. If it’s set to (“x”, “y”), the following patterns are all equivalent (and all bind the y attribute to the var variable):

Point(1, var)
Point(1, y=var)
Point(x=1, y=var)
Point(y=var, x=1)

A recommended way to read patterns is to look at them as an extended form of what you would put on the left of an assignment, to understand which variables would be set to what. Only the standalone names (like var above) are assigned to by a match statement. Dotted names (like foo.bar), attribute names (the x= and y= above) or class names (recognized by the “(…)” next to them like Point above) are never assigned to.

Patterns can be arbitrarily nested. For example, if we have a short list of Points, with __match_args__ added, we could match it like this:

class Point:
    __match_args__ = ('x', 'y')
    def __init__(self, x, y):
        self.x = x
        self.y = y

match points:
    case []:
        print("No points")
    case [Point(0, 0)]:
        print("The origin")
    case [Point(x, y)]:
        print(f"Single point {x}, {y}")
    case [Point(0, y1), Point(0, y2)]:
        print(f"Two on the Y axis at {y1}, {y2}")
    case _:
        print("Something else")

We can add an if clause to a pattern, known as a “guard”. If the guard is false, match goes on to try the next case block. Note that value capture happens before the guard is evaluated:

match point:
    case Point(x, y) if x == y:
        print(f"Y=X at {x}")
    case Point(x, y):
        print(f"Not on the diagonal")

Several other key features of this statement:

Like unpacking assignments, tuple and list patterns have exactly the same meaning and actually match arbitrary sequences. An important exception is that they don’t match iterators or strings.

Sequence patterns support extended unpacking: [x, y, *rest] and (x, y, *rest) work similar to unpacking assignments. The name after * may also be _, so (x, y, *_) matches a sequence of at least two items without binding the remaining items.

Mapping patterns: {"bandwidth": b, "latency": l} captures the "bandwidth" and "latency" values from a dictionary. Unlike sequence patterns, extra keys are ignored. An unpacking like **rest is also supported. (But **_ would be redundant, so it is not allowed.)

Subpatterns may be captured using the as keyword:

case (Point(x1, y1), Point(x2, y2) as p2): ...

will capture the second element of the input as p2 (as long as the input is a sequence of two points)

Most literals are compared by equality, however the singletons True, False and None are compared by identity.

Patterns may use named constants. These must be dotted names to prevent them from being interpreted as capture variable:

from enum import Enum
class Color(Enum):
    RED = 'red'
    GREEN = 'green'
    BLUE = 'blue'

color = Color(input("Enter your choice of 'red', 'blue' or 'green': "))

match color:
    case Color.RED:
        print("I see red!")
    case Color.GREEN:
        print("Grass is green")
    case Color.BLUE:
        print("I'm feeling the blues :(")

For a more detailed explanation and additional examples, you can look into PEP 636 [https://peps.python.org/pep-0636/] which is written in a tutorial format.

4.8. 함수 정의하기

피보나치 수열을 임의의 한도까지 출력하는 함수를 만들 수 있습니다:

>>> def fib(n):    # write Fibonacci series less than n
...     """Print a Fibonacci series less than n."""
...     a, b = 0, 1
...     while a < n:
...         print(a, end=' ')
...         a, b = b, a+b
...     print()
...
>>> # Now call the function we just defined:
>>> fib(2000)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

키워드 def는 함수 정의를 시작합니다. 함수 이름과 괄호로 싸인 형식 매개변수들의 목록이 뒤따릅니다. 함수의 바디를 형성하는 문장들이 다음 줄에서 시작되고, 반드시 들여쓰기 되어야 합니다.

함수 바디의 첫 번째 문장은 선택적으로 문자열 리터럴이 될 수 있습니다; 이 문자열 리터럴은 함수의 도큐멘테이션 문자열, 즉 독스트링 (docstring) 입니다. (독스트링에 대한 자세한 내용은 도큐멘테이션 문자열 에 나옵니다.) 독스트링을 사용해서 온라인이나 인쇄된 설명서를 자동 생성하거나, 사용자들이 대화형으로 코드를 열람할 수 있도록 하는 도구들이 있습니다; 여러분이 작성하는 코드에 독스트링을 첨부하는 것은 좋은 관습입니다, 그러니 버릇을 들이는 것이 좋습니다.

함수의 실행은 함수의 지역 변수들을 위한 새 심볼 테이블을 만듭니다. 좀 더 구체적으로, 함수에서의 모든 변수 대입들은 값을 지역 심볼 테이블에 저장합니다; 반면에 변수 참조는 먼저 지역 심볼 테이블을 본 다음, 전역 심볼 테이블을 본 후, 마지막으로 내장 이름들의 테이블을 살핍니다. 그래서, 참조될 수는 있다 하더라도, 전역 변수들과 둘러싸는 함수의 변수들은 함수 내에서 직접 값이 대입될 수 없습니다 (전역 변수를 global 문으로 명시하거나 둘러싸는 함수의 변수를 nonlocal 문으로 명시하지 않는 이상).

함수 호출로 전달되는 실제 매개변수들 (인자들)은 호출될 때 호출되는 함수의 지역 심볼 테이블에 만들어집니다; 그래서 인자들은 값에 의한 호출(call by value)로 전달됩니다 (값은 항상 객체의 값이 아니라 객체 참조입니다). [1] 함수가 다른 함수를 호출할 때, 또는 자신을 재귀적으로 호출할 때, 그 호출을 위한 새 지역 심볼 테이블이 만들어집니다.

함수 정의는 함수 이름을 현재 심볼 테이블의 함수 객체와 연결합니다. 인터프리터는 해당 이름이 가리키는 객체를 사용자 정의 함수로 인식합니다. 다른 이름은 같은 함수 객체를 가리킬 수 있으며 함수에 액세스하는 데 사용될 수도 있습니다:

>>> fib
<function fib at 10042ed0>
>>> f = fib
>>> f(100)
0 1 1 2 3 5 8 13 21 34 55 89

다른 언어들을 사용했다면, fib 가 값을 돌려주지 않기 때문에 함수가 아니라 프로시저라고 생각할 수 있습니다. 사실, return 문이 없는 함수도 값을 돌려줍니다, 비록 따분한 값이기는 하지만. 이 값은 None이라고 불립니다 (내장 이름입니다). None 이 출력할 유일한 값이라면, 인터프리터는 보통 None 값 출력을 억제합니다. 꼭 보길 원한다면 print()를 사용할 수 있습니다:

>>> fib(0)
>>> print(fib(0))
None

인쇄하는 대신, 피보나치 수열의 숫자들 리스트를 돌려주는 함수를 작성하는 것도 간단합니다:

>>> def fib2(n):  # return Fibonacci series up to n
...     """Return a list containing the Fibonacci series up to n."""
...     result = []
...     a, b = 0, 1
...     while a < n:
...         result.append(a)    # see below
...         a, b = b, a+b
...     return result
...
>>> f100 = fib2(100)    # call it
>>> f100                # write the result
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

여느 때처럼, 이 예는 몇 가지 새 파이썬 기능을 보여줍니다:

return 문은 함수로부터 값을 갖고 복귀하게 만듭니다. 표현식 인자 없는 return 은 None을 돌려줍니다. 함수의 끝으로 떨어지면 역시 None을 돌려줍니다.

The statement result.append(a) calls a method of the list object result. A method is a function that ‘belongs’ to an object and is named obj.methodname, where obj is some object (this may be an expression), and methodname is the name of a method that is defined by the object’s type. Different types define different methods. Methods of different types may have the same name without causing ambiguity. (It is possible to define your own object types and methods, using classes, see 클래스) The method append() shown in the example is defined for list objects; it adds a new element at the end of the list. In this example it is equivalent to result = result + [a], but more efficient.

4.9. 함수 정의 더 보기

정해지지 않은 개수의 인자들로 함수를 정의하는 것도 가능합니다. 세 가지 형식이 있는데, 조합할 수 있습니다.

4.9.1. 기본 인자 값

가장 쓸모 있는 형식은 하나나 그 이상 인자들의 기본값을 지정하는 것입니다. 정의된 것보다 더 적은 개수의 인자들로 호출될 수 있는 함수를 만듭니다. 예를 들어:

def ask_ok(prompt, retries=4, reminder='Please try again!'):
    while True:
        reply = input(prompt)
        if reply in {'y', 'ye', 'yes'}:
            return True
        if reply in {'n', 'no', 'nop', 'nope'}:
            return False
        retries = retries - 1
        if retries < 0:
            raise ValueError('invalid user response')
        print(reminder)

이 함수는 여러 가지 방법으로 호출될 수 있습니다:

오직 꼭 필요한 인자만 전달해서: ask_ok('정말 끝내길 원하세요?')

선택적 인자 하나를 제공해서: ask_ok('파일을 덮어써도 좋습니까?', 2)

또는 모든 인자를 제공해서: ask_ok('파일을 덮어써도 좋습니까?', 2, '자, 예나 아니요로만 답하세요!')

이 예는 in 키워드도 소개하고 있습니다. 시퀀스가 어떤 값을 가졌는지 아닌지를 검사합니다.

기본값은 함수 정의 시점에 정의되고 있는 스코프에서 구해집니다, 그래서

i = 5

def f(arg=i):
    print(arg)

i = 6
f()

는 5를 인쇄합니다.

중요한 주의사항: 기본값은 오직 한 번만 값이 구해집니다. 이것은 기본값이 리스트나 딕셔너리나 대부분 클래스의 인스턴스와 같은 가변 객체일 때 차이를 만듭니다. 예를 들어, 다음 함수는 계속되는 호출로 전달된 인자들을 누적합니다:

def f(a, L=[]):
    L.append(a)
    return L

print(f(1))
print(f(2))
print(f(3))

다음과 같은 것을 인쇄합니다

[1]
[1, 2]
[1, 2, 3]

연속된 호출 간에 기본값이 공유되지 않기를 원한다면, 대신 함수를 이런 식으로 쓸 수 있습니다:

def f(a, L=None):
    if L is None:
        L = []
    L.append(a)
    return L

4.9.2. 키워드 인자

함수는 kwarg=value 형식의 키워드 인자 를 사용해서 호출될 수 있습니다. 예를 들어, 다음 함수는:

def parrot(voltage, state='a stiff', action='voom', type='Norwegian Blue'):
    print("-- This parrot wouldn't", action, end=' ')
    print("if you put", voltage, "volts through it.")
    print("-- Lovely plumage, the", type)
    print("-- It's", state, "!")

하나의 필수 인자(voltage)와 세 개의 선택적 인자 (state, action, type) 를 받아들입니다. 이 함수는 다음과 같은 방법 중 아무것으로나 호출될 수 있습니다.

parrot(1000)                                          # 1 positional argument
parrot(voltage=1000)                                  # 1 keyword argument
parrot(voltage=1000000, action='VOOOOOM')             # 2 keyword arguments
parrot(action='VOOOOOM', voltage=1000000)             # 2 keyword arguments
parrot('a million', 'bereft of life', 'jump')         # 3 positional arguments
parrot('a thousand', state='pushing up the daisies')  # 1 positional, 1 keyword

하지만 다음과 같은 호출들은 모두 올바르지 않습니다:

parrot()                     # required argument missing
parrot(voltage=5.0, 'dead')  # non-keyword argument after a keyword argument
parrot(110, voltage=220)     # duplicate value for the same argument
parrot(actor='John Cleese')  # unknown keyword argument

함수 호출에서, 키워드 인자는 위치 인자 뒤에 나와야 합니다. 전달된 모든 키워드 인자는 함수가 받아들이는 인자 중 하나와 맞아야 하며 (예를 들어, actor는 parrot 함수의 올바른 인자가 아니다), 그 순서는 중요하지 않습니다. 이것들에는 필수 인자들도 포함됩니다 (예를 들어, parrot(voltage=1000) 도 올바릅니다). 어떤 인자도 두 개 이상의 값을 받을 수 없습니다. 여기, 이 제약 때문에 실패하는 예가 있습니다:

>>> def function(a):
...     pass
...
>>> function(0, a=0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: function() got multiple values for argument 'a'

**name 형식의 마지막 형식 매개변수가 존재하면, 형식 매개변수들에 대응하지 않는 모든 키워드 인자들을 담은 딕셔너리 (매핑 형 — dict 를 보세요) 를 받습니다. 이것은 *name (다음 서브섹션에서 설명합니다) 형식의 형식 매개변수와 조합될 수 있는데, 형식 매개변수 목록 밖의 위치 인자들을 담은 튜플을 받습니다. (*name은 **name 앞에 나와야 합니다.) 예를 들어, 이런 함수를 정의하면:

def cheeseshop(kind, *arguments, **keywords):
    print("-- Do you have any", kind, "?")
    print("-- I'm sorry, we're all out of", kind)
    for arg in arguments:
        print(arg)
    print("-" * 40)
    for kw in keywords:
        print(kw, ":", keywords[kw])

이런 식으로 호출될 수 있습니다:

cheeseshop("Limburger", "It's very runny, sir.",
           "It's really very, VERY runny, sir.",
           shopkeeper="Michael Palin",
           client="John Cleese",
           sketch="Cheese Shop Sketch")

그리고 당연히 이렇게 인쇄합니다:

-- Do you have any Limburger ?
-- I'm sorry, we're all out of Limburger
It's very runny, sir.
It's really very, VERY runny, sir.
----------------------------------------
shopkeeper : Michael Palin
client : John Cleese
sketch : Cheese Shop Sketch

인쇄되는 키워드 인자들의 순서 함수 호출로 전달된 순서와 일치함이 보장됨에 주목하세요.

4.9.3. 특수 매개 변수

기본적으로, 인자는 위치나 명시적인 키워드로 파이썬 함수에 전달될 수 있습니다. 가독성과 성능을 위해, 개발자가 항목이 위치, 위치나 키워드 또는 키워드로 전달되는지를 판단할 때 함수 정의만을 보면 되도록, 인자가 전달될 방법을 제한하면 좋습니다.

함수 정의는 다음과 같습니다:

def f(pos1, pos2, /, pos_or_kwd, *, kwd1, kwd2):
      -----------    ----------     ----------
        |             |                  |
        |        Positional or keyword   |
        |                                - Keyword only
         -- Positional only

여기서 /와 *는 선택적입니다. 사용하면, 이 기호는 인자가 함수에 전달되는 방식에 따른 매개 변수의 종류를 나타냅니다: 위치 전용, 위치-키워드 및 키워드 전용. 키워드 매개 변수는 명명된(named) 매개 변수라고도 합니다.

4.9.3.1. 위치-키워드(Positional-or-Keyword) 인자

함수 정의에 /와 *가 없으면, 인자를 위치나 키워드로 함수에 전달할 수 있습니다.

4.9.3.2. 위치 전용 매개 변수

좀 더 자세하게 살펴보면, 특정 매개 변수를 위치 전용으로 표시할 수 있습니다. 위치 전용이면, 매개 변수의 순서가 중요하며, 키워드로 매개 변수를 전달할 수 없습니다. 위치 전용 매개 변수는 / (슬래시) 앞에 놓입니다. /는 위치 전용 매개 변수를 나머지 매개 변수들로부터 논리적으로 분리하는 데 사용됩니다. 함수 정의에 /가 없으면, 위치 전용 매개 변수는 없습니다.

/ 다음의 매개 변수는 위치-키워드나 키워드 전용일 수 있습니다.

4.9.3.3. 키워드 전용 인자

매개 변수를 키워드 인자로 전달해야 함을 나타내도록, 매개 변수를 키워드 전용으로 표시하려면, 첫 번째 키워드 전용 매개 변수 바로 전에 인자 목록에 *를 넣으십시오.

4.9.3.4. 함수 예제

/와 * 마커에 주의를 기울이는 다음 예제 함수 정의를 고려하십시오:

>>> def standard_arg(arg):
...     print(arg)
...
>>> def pos_only_arg(arg, /):
...     print(arg)
...
>>> def kwd_only_arg(*, arg):
...     print(arg)
...
>>> def combined_example(pos_only, /, standard, *, kwd_only):
...     print(pos_only, standard, kwd_only)

첫 번째 함수 정의 standard_arg는 가장 익숙한 형식으로, 호출 규칙에 아무런 제한을 두지 않으며 인자는 위치나 키워드로 전달될 수 있습니다:

>>> standard_arg(2)
2

>>> standard_arg(arg=2)
2

두 번째 함수 pos_only_arg는 함수 정의에 /가 있으므로 위치 매개 변수만 사용하도록 제한됩니다:

>>> pos_only_arg(1)
1

>>> pos_only_arg(arg=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: pos_only_arg() got some positional-only arguments passed as keyword arguments: 'arg'

The third function kwd_only_arg only allows keyword arguments as indicated by a * in the function definition:

>>> kwd_only_arg(3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: kwd_only_arg() takes 0 positional arguments but 1 was given

>>> kwd_only_arg(arg=3)
3

마지막은 같은 함수 정의에서 세 가지 호출 규칙을 모두 사용합니다:

>>> combined_example(1, 2, 3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: combined_example() takes 2 positional arguments but 3 were given

>>> combined_example(1, 2, kwd_only=3)
1 2 3

>>> combined_example(1, standard=2, kwd_only=3)
1 2 3

>>> combined_example(pos_only=1, standard=2, kwd_only=3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: combined_example() got some positional-only arguments passed as keyword arguments: 'pos_only'

마지막으로, 위치 인자 name과 name을 키로 가지는 **kwds 사이에 잠재적인 충돌이 있는 이 함수 정의를 고려하십시오:

def foo(name, **kwds):
    return 'name' in kwds

'name' 키워드는 항상 첫 번째 매개 변수에 결합하므로 True를 반환할 수 있는 호출은 불가능합니다. 예를 들면:

>>> foo(1, **{'name': 2})
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: foo() got multiple values for argument 'name'
>>>

그러나 /(위치 전용 인자)를 사용하면, name을 위치 인자로, 동시에 'name'을 키워드 인자의 키로 사용할 수 있으므로 가능합니다:

>>> def foo(name, /, **kwds):
...     return 'name' in kwds
...
>>> foo(1, **{'name': 2})
True

즉, 위치 전용 매개 변수의 이름을 **kwds에서 모호함 없이 사용할 수 있습니다.

4.9.3.5. 복습

사용 사례가 함수 정의에서 어떤 매개 변수를 사용할지 결정합니다:

def f(pos1, pos2, /, pos_or_kwd, *, kwd1, kwd2):

지침으로서:

매개 변수의 이름을 사용자가 사용할 수 없도록 하려면 위치 전용을 사용하십시오. 매개 변수 이름이 실제 의미가 없을 때, 함수가 호출될 때 인자의 순서를 강제하려고 할 때, 또는 일부 위치 매개 변수와 임의의 키워드를 받아들이고 싶을 때 유용합니다.

이름이 의미가 있고 함수 정의가 이름을 명시적으로 지정함으로써 더 이해하기 쉬워지거나, 사용자가 전달되는 인자의 위치에 의존하지 못하도록 하려면 키워드 전용을 사용하십시오.

API의 경우, 향후 매개 변수의 이름이 수정될 때 비호환 API 변경이 발생하는 것을 방지하려면 위치 전용을 사용하십시오.

4.9.4. 임의의 인자 목록

마지막으로, 가장 덜 사용되는 옵션은 함수가 임의의 개수 인자로 호출될 수 있도록 지정하는 것입니다. 이 인자들은 튜플로 묶입니다 (튜플과 시퀀스 을 보세요). 가변 길이 인자 앞에, 없거나 여러 개의 일반 인자들이 올 수 있습니다.

def write_multiple_items(file, separator, *args):
    file.write(separator.join(args))

Normally, these variadic arguments will be last in the list of formal parameters, because they scoop up all remaining input arguments that are passed to the function. Any formal parameters which occur after the *args parameter are ‘keyword-only’ arguments, meaning that they can only be used as keywords rather than positional arguments.

>>> def concat(*args, sep="/"):
...     return sep.join(args)
...
>>> concat("earth", "mars", "venus")
'earth/mars/venus'
>>> concat("earth", "mars", "venus", sep=".")
'earth.mars.venus'

4.9.5. 인자 목록 언 패킹

인자들이 이미 리스트나 튜플에 있지만, 분리된 위치 인자들을 요구하는 함수 호출을 위해 언 패킹 해야 하는 경우 반대 상황이 벌어집니다. 예를 들어, 내장 range() 함수는 별도의 start와 stop 인자를 기대합니다. 그것들이 따로 있지 않으면, 리스트와 튜플로부터 인자를 언 패킹하기 위해 *-연산자를 사용해서 함수를 호출하면 됩니다:

>>> list(range(3, 6))            # normal call with separate arguments
[3, 4, 5]
>>> args = [3, 6]
>>> list(range(*args))            # call with arguments unpacked from a list
[3, 4, 5]

같은 방식으로 딕셔너리도 **-연산자를 써서 키워드 인자를 전달할 수 있습니다:

>>> def parrot(voltage, state='a stiff', action='voom'):
...     print("-- This parrot wouldn't", action, end=' ')
...     print("if you put", voltage, "volts through it.", end=' ')
...     print("E's", state, "!")
...
>>> d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
>>> parrot(**d)
-- This parrot wouldn't VOOM if you put four million volts through it. E's bleedin' demised !

4.9.6. 람다 표현식

lambda 키워드들 사용해서 작고 이름 없는 함수를 만들 수 있습니다. 이 함수는 두 인자의 합을 돌려줍니다: lambda a, b: a+b. 함수 객체가 있어야 하는 곳이면 어디나 람다 함수가 사용될 수 있습니다. 문법적으로는 하나의 표현식으로 제한됩니다. 의미적으로는, 일반적인 함수 정의의 편의 문법일 뿐입니다. 중첩된 함수 정의처럼, 람다 함수는 둘러싸는 스코프에 있는 변수들을 참조할 수 있습니다:

>>> def make_incrementor(n):
...     return lambda x: x + n
...
>>> f = make_incrementor(42)
>>> f(0)
42
>>> f(1)
43

위의 예는 함수를 돌려주기 위해 람다 표현식을 사용합니다. 또 다른 용도는 작은 함수를 인자로 전달하는 것입니다:

>>> pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
>>> pairs.sort(key=lambda pair: pair[1])
>>> pairs
[(4, 'four'), (1, 'one'), (3, 'three'), (2, 'two')]

4.9.7. 도큐멘테이션 문자열

여기에 도큐멘테이션 문자열의 내용과 포매팅에 관한 몇 가지 관례가 있습니다.

첫 줄은 항상 객체의 목적을 짧고, 간결하게 요약해야 합니다. 간결함을 위해, 객체의 이름이나 형을 명시적으로 언급하지 않아야 하는데, 이것들은 다른 방법으로 제공되기 때문입니다 (이름이 함수의 작업을 설명하는 동사라면 예외입니다). 이 줄은 대문자로 시작하고 마침표로 끝나야 합니다.

도큐멘테이션 문자열에 여러 줄이 있다면, 두 번째 줄은 비어있어서, 시각적으로 요약과 나머지 설명을 분리해야 합니다. 뒤따르는 줄들은 하나나 그 이상의 문단으로, 객체의 호출 규약, 부작용 등을 설명해야 합니다.

파이썬 파서는 여러 줄 문자열 리터럴에서 들여쓰기를 제거하지 않기 때문에, 설명서를 처리하는 도구들은 필요하면 들여쓰기를 제거합니다. 이것은 다음과 같은 관례를 사용합니다. 문자열의 첫줄 뒤에 오는 첫 번째 비어있지 않은 줄이 전체 도튜멘테이션 문자열의 들여쓰기 수준을 결정합니다. (우리는 첫 줄을 사용할 수 없는데, 일반적으로 문자열을 시작하는 따옴표에 붙어있어서 들여쓰기가 문자열 리터럴의 것을 반영하지 않기 때문입니다.) 이 들여쓰기와 “동등한” 공백이 문자열의 모든 줄의 시작 부분에서 제거됩니다. 덜 들여쓰기 된 줄이 나타나지는 말아야 하지만, 나타난다면 모든 앞부분의 공백이 제거됩니다. 공백의 동등성은 탭 확장 (보통 8개의 스페이스) 후에 검사됩니다.

여기 여러 줄 독스트링의 예가 있습니다:

>>> def my_function():
...     """Do nothing, but document it.
...
...     No, really, it doesn't do anything.
...     """
...     pass
...
>>> print(my_function.__doc__)
Do nothing, but document it.

    No, really, it doesn't do anything.

4.9.8. 함수 어노테이션

함수 어노테이션 은 사용자 정의 함수가 사용하는 형들에 대한 완전히 선택적인 메타데이터 정보입니다 (자세한 내용은 PEP 3107 [https://peps.python.org/pep-3107/] 과 PEP 484 [https://peps.python.org/pep-0484/] 를 보세요).

Annotations are stored in the __annotations__ attribute of the function as a dictionary and have no effect on any other part of the function. Parameter annotations are defined by a colon after the parameter name, followed by an expression evaluating to the value of the annotation. Return annotations are defined by a literal ->, followed by an expression, between the parameter list and the colon denoting the end of the def statement. The following example has a required argument, an optional argument, and the return value annotated:

>>> def f(ham: str, eggs: str = 'eggs') -> str:
...     print("Annotations:", f.__annotations__)
...     print("Arguments:", ham, eggs)
...     return ham + ' and ' + eggs
...
>>> f('spam')
Annotations: {'ham': <class 'str'>, 'return': <class 'str'>, 'eggs': <class 'str'>}
Arguments: spam eggs
'spam and eggs'

4.10. 막간극: 코딩 스타일

이제 여러분은 파이썬의 더 길고, 더 복잡한 조각들을 작성하려고 합니다, 코딩 스타일에 대해 말할 적절한 시간입니다. 대부분 언어는 서로 다른 스타일로 작성될 (또는 더 간략하게, 포맷될) 수 있습니다; 어떤 것들은 다른 것들보다 더 읽기 쉽습니다. 다른 사람들이 여러분의 코드를 읽기 쉽게 만드는 것은 항상 좋은 생각이고, 훌륭한 코딩 스타일을 도입하는 것은 그렇게 하는 데 큰 도움을 줍니다.

파이썬을 위해, 대부분 프로젝트가 고수하는 스타일 가이드로 PEP 8 [https://peps.python.org/pep-0008/]이 나왔습니다; 이것은 매우 읽기 쉽고 눈이 편안한 코딩 스타일을 장려합니다. 모든 파이썬 개발자는 언젠가는 이 문서를 읽어야 합니다; 여러분을 위해 가장 중요한 부분들을 추려봤습니다:

들려 쓰기에 4-스페이스를 사용하고, 탭을 사용하지 마세요.

4개의 스페이스는 작은 들여쓰기 (더 많은 중첩 도를 허락합니다) 와 큰 들여쓰기 (읽기 쉽습니다) 사이의 좋은 절충입니다. 탭은 혼란을 일으키고, 없애는 것이 최선입니다.

79자를 넘지 않도록 줄 넘김 하세요.

이것은 작은 화면을 가진 사용자를 돕고 큰 화면에서는 여러 코드 파일들을 나란히 볼 수 있게 합니다.

함수, 클래스, 함수 내의 큰 코드 블록 사이에 빈 줄을 넣어 분리하세요.

가능하다면, 주석은 별도의 줄로 넣으세요.

독스트링을 사용하세요.

연산자들 주변과 콤마 뒤에 스페이스를 넣고, 괄호 바로 안쪽에는 스페이스를 넣지 마세요: a = f(1, 2) + g(3, 4).

클래스와 함수들에 일관성 있는 이름을 붙이세요; 관례는 클래스의 경우 UpperCamelCase, 함수와 메서드의 경우 lowercase_with_underscores입니다. 첫 번째 메서드 인자의 이름으로는 항상 self를 사용하세요 (클래스와 메서드에 대한 자세한 내용은 클래스와의 첫 만남 을 보세요).

여러분의 코드를 국제적인 환경에서 사용하려고 한다면 특별한 인코딩을 사용하지 마세요. 어떤 경우에도 파이썬의 기본, UTF-8, 또는 단순 ASCII조차, 이 최선입니다.

마찬가지로, 다른 언어를 사용하는 사람이 코드를 읽거나 유지할 약간의 가능성만 있더라도, 식별자에 ASCII 이외의 문자를 사용하지 마세요.

각주

[1]

실제로, 객체 참조에 의한 호출 (call by object reference) 이 더 좋은 표현인데, 가변 객체가 전달되면, 호출자는 피호출자가 만든 변경을 볼 수 있기 때문입니다 (가령 리스트에 항목을 추가합니다).

5. 자료 구조

이 장에서는 여러분이 이미 배운 것들을 좀 더 자세히 설명하고, 몇 가지 새로운 것들을 덧붙입니다.

5.1. 리스트 더 보기

리스트 자료 형은 몇 가지 메서드들을 더 갖고 있습니다. 이것들이 리스트 객체의 모든 메서드 들입니다:

list.append(x)

Add an item to the end of the list. Similar to a[len(a):] = [x].

list.extend(iterable)

Extend the list by appending all the items from the iterable. Similar to a[len(a):] = iterable.

list.insert(i, x)

주어진 위치에 항목을 삽입합니다. 첫 번째 인자는 삽입되는 요소가 갖게 될 인덱스입니다. 그래서 a.insert(0, x) 는 리스트의 처음에 삽입하고, a.insert(len(a), x) 는 a.append(x) 와 동등합니다.

list.remove(x)

리스트에서 값이 x 와 같은 첫 번째 항목을 삭제합니다. 그런 항목이 없으면 ValueError를 일으킵니다.

list.pop([i])

Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list. It raises an IndexError if the list is empty or the index is outside the list range.

list.clear()

Remove all items from the list. Similar to del a[:].

list.index(x[, start[, end]])

리스트에 있는 항목 중 값이 x 와 같은 첫 번째 것의 0부터 시작하는 인덱스를 돌려줍니다. 그런 항목이 없으면 ValueError 를 일으킵니다.

선택적인 인자 start 와 end 는 슬라이스 표기법처럼 해석되고, 검색을 리스트의 특별한 서브 시퀀스로 제한하는 데 사용됩니다. 돌려주는 인덱스는 start 인자가 아니라 전체 시퀀스의 시작을 기준으로 합니다.

list.count(x)

리스트에서 x 가 등장하는 횟수를 돌려줍니다.

list.sort(*, key=None, reverse=False)

리스트의 항목들을 제자리에서 정렬합니다 (인자들은 정렬 커스터마이제이션에 사용될 수 있습니다. 설명은 sorted() 를 보세요).

list.reverse()

리스트의 요소들을 제자리에서 뒤집습니다.

list.copy()

Return a shallow copy of the list. Similar to a[:].

리스트 메서드 대부분을 사용하는 예:

>>> fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', 'banana']
>>> fruits.count('apple')
2
>>> fruits.count('tangerine')
0
>>> fruits.index('banana')
3
>>> fruits.index('banana', 4)  # Find next banana starting at position 4
6
>>> fruits.reverse()
>>> fruits
['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']
>>> fruits.append('grape')
>>> fruits
['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']
>>> fruits.sort()
>>> fruits
['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']
>>> fruits.pop()
'pear'

You might have noticed that methods like insert, remove or sort that only modify the list have no return value printed – they return the default None. [1] This is a design principle for all mutable data structures in Python.

Another thing you might notice is that not all data can be sorted or compared. For instance, [None, 'hello', 10] doesn’t sort because integers can’t be compared to strings and None can’t be compared to other types. Also, there are some types that don’t have a defined ordering relation. For example, 3+4j < 5+7j isn’t a valid comparison.

5.1.1. 리스트를 스택으로 사용하기

The list methods make it very easy to use a list as a stack, where the last element added is the first element retrieved (“last-in, first-out”). To add an item to the top of the stack, use append(). To retrieve an item from the top of the stack, use pop() without an explicit index. For example:

>>> stack = [3, 4, 5]
>>> stack.append(6)
>>> stack.append(7)
>>> stack
[3, 4, 5, 6, 7]
>>> stack.pop()
7
>>> stack
[3, 4, 5, 6]
>>> stack.pop()
6
>>> stack.pop()
5
>>> stack
[3, 4]

5.1.2. 리스트를 큐로 사용하기

리스트를 큐로 사용하는 것도 가능한데, 처음으로 넣은 요소가 처음으로 꺼내지는 요소입니다 (“first-in, first-out”); 하지만, 리스트는 이 목적에는 효율적이지 않습니다. 리스트의 끝에 덧붙이거나, 끝에서 꺼내는 것은 빠르지만, 리스트의 머리에 덧붙이거나 머리에서 꺼내는 것은 느립니다 (다른 요소들을 모두 한 칸씩 이동시켜야 하기 때문입니다).

큐를 구현하려면, 양 끝에서의 덧붙이기와 꺼내기가 모두 빠르도록 설계된 collections.deque 를 사용하세요. 예를 들어:

>>> from collections import deque
>>> queue = deque(["Eric", "John", "Michael"])
>>> queue.append("Terry")           # Terry arrives
>>> queue.append("Graham")          # Graham arrives
>>> queue.popleft()                 # The first to arrive now leaves
'Eric'
>>> queue.popleft()                 # The second to arrive now leaves
'John'
>>> queue                           # Remaining queue in order of arrival
deque(['Michael', 'Terry', 'Graham'])

5.1.3. 리스트 컴프리헨션

리스트 컴프리헨션은 리스트를 만드는 간결한 방법을 제공합니다. 흔한 용도는, 각 요소가 다른 시퀀스나 이터러블의 멤버들에 어떤 연산을 적용한 결과인 리스트를 만들거나, 어떤 조건을 만족하는 요소들로 구성된 서브 시퀀스를 만드는 것입니다.

예를 들어, 제곱수의 리스트를 만들고 싶다고 가정하자, 이런 식입니다:

>>> squares = []
>>> for x in range(10):
...     squares.append(x**2)
...
>>> squares
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

이것은 x 라는 이름의 변수를 만들고 (또는 덮어쓰고) 루프가 종료된 후에도 남아있게 만든다는 것에 유의하세요. 어떤 부작용도 없이, 제곱수의 리스트를 이런 식으로 계산할 수 있습니다:

squares = list(map(lambda x: x**2, range(10)))

또는, 이렇게 할 수도 있습니다:

squares = [x**2 for x in range(10)]

이것이 더 간결하고 읽기 쉽습니다.

리스트 컴프리헨션은 표현식과 그 뒤를 따르는 for 절과 없거나 여러 개의 for 나 if 절들을 감싸는 대괄호로 구성됩니다. 그 결과는 새 리스트인데, for 와 if 절의 문맥에서 표현식의 값을 구해서 만들어집니다. 예를 들어, 이 리스트 컴프리헨션은 두 리스트의 요소들을 서로 같지 않은 것끼리 결합합니다:

>>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]

그리고, 이것은 다음과 동등합니다:

>>> combs = []
>>> for x in [1,2,3]:
...     for y in [3,1,4]:
...         if x != y:
...             combs.append((x, y))
...
>>> combs
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]

두 코드 조각에서 for 와 if 문의 순서가 같음에 유의하세요.

표현식이 튜플이면 (즉 앞의 예에서 (x, y)), 반드시 괄호로 둘러싸야 합니다.

>>> vec = [-4, -2, 0, 2, 4]
>>> # create a new list with the values doubled
>>> [x*2 for x in vec]
[-8, -4, 0, 4, 8]
>>> # filter the list to exclude negative numbers
>>> [x for x in vec if x >= 0]
[0, 2, 4]
>>> # apply a function to all the elements
>>> [abs(x) for x in vec]
[4, 2, 0, 2, 4]
>>> # call a method on each element
>>> freshfruit = ['  banana', '  loganberry ', 'passion fruit  ']
>>> [weapon.strip() for weapon in freshfruit]
['banana', 'loganberry', 'passion fruit']
>>> # create a list of 2-tuples like (number, square)
>>> [(x, x**2) for x in range(6)]
[(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]
>>> # the tuple must be parenthesized, otherwise an error is raised
>>> [x, x**2 for x in range(6)]
  File "<stdin>", line 1
    [x, x**2 for x in range(6)]
     ^^^^^^^
SyntaxError: did you forget parentheses around the comprehension target?
>>> # flatten a list using a listcomp with two 'for'
>>> vec = [[1,2,3], [4,5,6], [7,8,9]]
>>> [num for elem in vec for num in elem]
[1, 2, 3, 4, 5, 6, 7, 8, 9]

리스트 컴프리헨션은 복잡한 표현식과 중첩된 함수들을 포함할 수 있습니다:

>>> from math import pi
>>> [str(round(pi, i)) for i in range(1, 6)]
['3.1', '3.14', '3.142', '3.1416', '3.14159']

5.1.4. 중첩된 리스트 컴프리헨션

리스트 컴프리헨션의 첫 표현식으로 임의의 표현식이 올 수 있는데, 다른 리스트 컴프리헨션도 가능합니다.

다음과 같은 길이가 4인 리스트 3개의 리스트로 구현된 3x4 행렬의 예를 봅시다:

>>> matrix = [
...     [1, 2, 3, 4],
...     [5, 6, 7, 8],
...     [9, 10, 11, 12],
... ]

다음 리스트 컴프리헨션은 행과 열을 전치 시킵니다:

>>> [[row[i] for row in matrix] for i in range(4)]
[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

As we saw in the previous section, the inner list comprehension is evaluated in the context of the for that follows it, so this example is equivalent to:

>>> transposed = []
>>> for i in range(4):
...     transposed.append([row[i] for row in matrix])
...
>>> transposed
[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

이것은 다시 다음과 같습니다:

>>> transposed = []
>>> for i in range(4):
...     # the following 3 lines implement the nested listcomp
...     transposed_row = []
...     for row in matrix:
...         transposed_row.append(row[i])
...     transposed.append(transposed_row)
...
>>> transposed
[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

실제 세상에서는, 복잡한 흐름문보다 내장 함수들을 선호해야 합니다. 이 경우에는 zip() 함수가 제 역할을 할 수 있습니다:

>>> list(zip(*matrix))
[(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]

이 줄에 나오는 애스터리스크에 대한 자세한 내용은 인자 목록 언 패킹 을 보세요.

5.2. del 문

There is a way to remove an item from a list given its index instead of its value: the del statement. This differs from the pop() method which returns a value. The del statement can also be used to remove slices from a list or clear the entire list (which we did earlier by assignment of an empty list to the slice). For example:

>>> a = [-1, 1, 66.25, 333, 333, 1234.5]
>>> del a[0]
>>> a
[1, 66.25, 333, 333, 1234.5]
>>> del a[2:4]
>>> a
[1, 66.25, 1234.5]
>>> del a[:]
>>> a
[]

del 는 변 자체를 삭제하는데에도 사용될 수 있습니다:

>>> del a

이후에 이름 a 를 참조하는 것은 에러입니다 (적어도 다른 값이 새로 대입되기 전까지). 뒤에서 del 의 다른 용도를 보게 됩니다.

5.3. 튜플과 시퀀스

리스트와 문자열이 인덱싱과 슬라이싱 연산과 같은 많은 성질을 공유함을 보았습니다. 이것들은 시퀀스 자료 형의 두 가지 예입니다 (시퀀스 형 — list, tuple, range 를 보세요). 파이썬은 진화하는 언어이기 때문에, 다른 시퀀스 자료형이 추가될 수도 있습니다. 다른 표준 시퀀스 자료 형이 있습니다: 튜플 입니다.

튜플은 쉼표로 구분되는 여러 값으로 구성됩니다. 예를 들어:

>>> t = 12345, 54321, 'hello!'
>>> t[0]
12345
>>> t
(12345, 54321, 'hello!')
>>> # Tuples may be nested:
>>> u = t, (1, 2, 3, 4, 5)
>>> u
((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))
>>> # Tuples are immutable:
>>> t[0] = 88888
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment
>>> # but they can contain mutable objects:
>>> v = ([1, 2, 3], [3, 2, 1])
>>> v
([1, 2, 3], [3, 2, 1])

여러분이 보듯이, 출력되는 튜플은 항상 괄호로 둘러싸입니다, 그래서 중첩된 튜플이 올바르게 해석됩니다; 종종 괄호가 필요하기는 하지만 (튜플이 더 큰 표현식의 일부일 때), 둘러싼 괄호와 함께 또는 없이 입력될 수 있습니다. 튜플의 개별 항목에 대입하는 것은 가능하지 않지만, 리스트 같은 가변 객체를 포함하는 튜플을 만들 수는 있습니다.

튜플이 리스트처럼 보인다 하더라도, 이것들은 다른 상황에서 다른 목적으로 사용됩니다. 튜플은 불변 이고, 보통 이질적인 요소들의 시퀀스를 포함합니다. 요소들은 언 패킹 (이 섹션의 뒤에 나온다) 이나 인덱싱 (또는 네임드 튜플 의 경우는 어트리뷰트로도) 으로 액세스합니다. 리스트는 가변 이고, 요소들은 보통 등질 적이고 리스트에 대한 이터레이션으로 액세스 됩니다.

특별한 문제는 비었거나 하나의 항목을 갖는 튜플을 만드는 것입니다: 이 경우를 수용하기 위해 문법은 추가적인 예외 사항을 갖고 있습니다. 빈 튜플은 빈 괄호 쌍으로 만들어집니다; 하나의 항목으로 구성된 튜플은 값 뒤에 쉼표를 붙여서 만듭니다 (값 하나를 괄호로 둘러싸기만 하는 것으로는 충분하지 않습니다). 추합니다, 하지만 효과적입니다. 예를 들어:

>>> empty = ()
>>> singleton = 'hello',    # <-- note trailing comma
>>> len(empty)
0
>>> len(singleton)
1
>>> singleton
('hello',)

문장 t = 12345, 54321, 'hello!' 는 튜플 패킹 의 예입니다: 값 12345, 54321, 'hello!' 는 함께 튜플로 패킹 됩니다. 반대 연산 또한 가능합니다:

>>> x, y, z = t

이것은, 충분히 적절하게도, 시퀀스 언 패킹 이라고 불리고 오른쪽에 어떤 시퀀스가 와도 됩니다. 시퀀스 언 패킹은 등호의 좌변에 시퀀스에 있는 요소들과 같은 개수의 변수들이 올 것을 요구합니다. 다중 대입은 사실 튜플 패킹과 시퀀스 언 패킹의 조합일뿐이라는 것에 유의하세요.

5.4. 집합

파이썬은 집합 을 위한 자료 형도 포함합니다. 집합은 중복되는 요소가 없는 순서 없는 컬렉션입니다. 기본적인 용도는 멤버십 검사와 중복 엔트리 제거입니다. 집합 객체는 합집합, 교집합, 차집합, 대칭 차집합과 같은 수학적인 연산들도 지원합니다.

집합을 만들 때는 중괄호나 set() 함수를 사용할 수 있습니다. 주의사항: 빈 집합을 만들려면 set() 을 사용해야 합니다. {} 가 아닙니다; 후자는 빈 딕셔너리를 만드는데, 다음 섹션에서 다룹니다.

여기 간략한 실연이 있습니다:

>>> basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
>>> print(basket)                      # show that duplicates have been removed
{'orange', 'banana', 'pear', 'apple'}
>>> 'orange' in basket                 # fast membership testing
True
>>> 'crabgrass' in basket
False

>>> # Demonstrate set operations on unique letters from two words
>>>
>>> a = set('abracadabra')
>>> b = set('alacazam')
>>> a                                  # unique letters in a
{'a', 'r', 'b', 'c', 'd'}
>>> a - b                              # letters in a but not in b
{'r', 'd', 'b'}
>>> a | b                              # letters in a or b or both
{'a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'}
>>> a & b                              # letters in both a and b
{'a', 'c'}
>>> a ^ b                              # letters in a or b but not both
{'r', 'd', 'b', 'm', 'z', 'l'}

리스트 컴프리헨션 과 유사하게, 집합 컴프리헨션도 지원됩니다:

>>> a = {x for x in 'abracadabra' if x not in 'abc'}
>>> a
{'r', 'd'}

5.5. 딕셔너리

Another useful data type built into Python is the dictionary (see 매핑 형 — dict). Dictionaries are sometimes found in other languages as “associative memories” or “associative arrays”. Unlike sequences, which are indexed by a range of numbers, dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys. Tuples can be used as keys if they contain only strings, numbers, or tuples; if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key. You can’t use lists as keys, since lists can be modified in place using index assignments, slice assignments, or methods like append() and extend().

딕셔너리를 (한 딕셔너리 안에서) 키가 중복되지 않는다는 제약 조건을 가진 키: 값 쌍의 집합으로 생각하는 것이 최선입니다. 중괄호 쌍은 빈 딕셔너리를 만듭니다: {}. 중괄호 안에 쉼표로 분리된 키:값 쌍들의 목록을 넣으면, 딕셔너리에 초기 키:값 쌍들을 제공합니다; 이것이 딕셔너리가 출력되는 방식이기도 합니다.

딕셔너리의 주 연산은 값을 키와 함께 저장하고 주어진 키로 값을 추출하는 것입니다. del 로 키:값 쌍을 삭제하는 것도 가능합니다. 이미 사용하고 있는 키로 저장하면, 그 키로 저장된 예전 값은 잊힙니다. 존재하지 않는 키로 값을 추출하는 것은 에러입니다.

딕셔러리에 list(d) 를 수행하면 딕셔너리에서 사용되고 있는 모든 키의 리스트를 삽입 순서대로 돌려줍니다 (정렬을 원하면 대신 sorted(d) 를 사용하면 됩니다). 하나의 키가 딕셔너리에 있는지 검사하려면, in 키워드들 사용하세요.

여기에 딕셔너리를 사용하는 조그마한 예가 있습니다:

>>> tel = {'jack': 4098, 'sape': 4139}
>>> tel['guido'] = 4127
>>> tel
{'jack': 4098, 'sape': 4139, 'guido': 4127}
>>> tel['jack']
4098
>>> del tel['sape']
>>> tel['irv'] = 4127
>>> tel
{'jack': 4098, 'guido': 4127, 'irv': 4127}
>>> list(tel)
['jack', 'guido', 'irv']
>>> sorted(tel)
['guido', 'irv', 'jack']
>>> 'guido' in tel
True
>>> 'jack' not in tel
False

dict() 생성자는 키-값 쌍들의 시퀀스로 부터 직접 딕셔너리를 구성합니다.

>>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])
{'sape': 4139, 'guido': 4127, 'jack': 4098}

이에 더해, 딕셔너리 컴프리헨션은 임의의 키와 값 표현식들로 부터 딕셔너리를 만드는데 사용될 수 있습니다:

>>> {x: x**2 for x in (2, 4, 6)}
{2: 4, 4: 16, 6: 36}

키가 간단한 문자열일 때, 때로 키워드 인자들을 사용해서 쌍을 지정하기가 쉽습니다:

>>> dict(sape=4139, guido=4127, jack=4098)
{'sape': 4139, 'guido': 4127, 'jack': 4098}

5.6. 루프 테크닉

When looping through dictionaries, the key and corresponding value can be retrieved at the same time using the items() method.

>>> knights = {'gallahad': 'the pure', 'robin': 'the brave'}
>>> for k, v in knights.items():
...     print(k, v)
...
gallahad the pure
robin the brave

시퀀스를 루핑할 때, enumerate() 함수를 사용하면 위치 인덱스와 대응하는 값을 동시에 얻을 수 있습니다.

>>> for i, v in enumerate(['tic', 'tac', 'toe']):
...     print(i, v)
...
0 tic
1 tac
2 toe

둘이나 그 이상의 시퀀스를 동시에 루핑하려면, zip() 함수로 엔트리들의 쌍을 만들 수 있습니다.

>>> questions = ['name', 'quest', 'favorite color']
>>> answers = ['lancelot', 'the holy grail', 'blue']
>>> for q, a in zip(questions, answers):
...     print('What is your {0}?  It is {1}.'.format(q, a))
...
What is your name?  It is lancelot.
What is your quest?  It is the holy grail.
What is your favorite color?  It is blue.

시퀀스를 거꾸로 루핑하려면, 먼저 정방향으로 시퀀스를 지정한 다음에 reversed() 함수를 호출하세요.

>>> for i in reversed(range(1, 10, 2)):
...     print(i)
...
9
7
5
3
1

정렬된 순서로 시퀀스를 루핑하려면, sorted() 함수를 사용해서 소스를 변경하지 않고도 정렬된 새 리스트를 받을 수 있습니다.

>>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']
>>> for i in sorted(basket):
...     print(i)
...
apple
apple
banana
orange
orange
pear

시퀀스에 대해 set()을 사용하면 중복 요소를 제거합니다. 시퀀스에 대해 set()과 sorted()를 함께 사용하는 것은 시퀀스의 고유 한 요소를 정렬된 순서로 루핑하는 관용적 방법입니다.

>>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']
>>> for f in sorted(set(basket)):
...     print(f)
...
apple
banana
orange
pear

때로 루프를 돌고 있는 리스트를 변경하고픈 유혹을 느낍니다; 하지만, 종종, 대신 새 리스트를 만드는 것이 더 간단하고 더 안전합니다.

>>> import math
>>> raw_data = [56.2, float('NaN'), 51.7, 55.3, 52.5, float('NaN'), 47.8]
>>> filtered_data = []
>>> for value in raw_data:
...     if not math.isnan(value):
...         filtered_data.append(value)
...
>>> filtered_data
[56.2, 51.7, 55.3, 52.5, 47.8]

5.7. 조건 더 보기

while 과 if 문에서 사용되는 조건에는 비교뿐만 아니라 모든 연산자를 사용할 수 있습니다.

The comparison operators in and not in are membership tests that determine whether a value is in (or not in) a container. The operators is and is not compare whether two objects are really the same object. All comparison operators have the same priority, which is lower than that of all numerical operators.

비교는 연쇄할 수 있습니다. 예를 들어, a < b == c 는, a 가 b 보다 작고, 동시에 b 가 c 와 같은지 검사합니다.

비교는 논리 연산자 and 와 or 를 사용해서 결합할 수 있고, 비교의 결과는 (또는 그 밖의 모든 논리 표현식은) not 으로 부정될 수 있습니다. 이것들은 비교 연산자보다 낮은 우선순위를 갖습니다. 이것 간에는 not 이 가장 높은 우선순위를 갖고, or 가 가장 낮습니다. 그래서 A and not B or C 는 (A and (not B)) or C 와 동등합니다. 여느 때처럼, 원하는 조합을 표현하기 위해 괄호를 사용할 수 있습니다.

논리 연산자 and 와 or 는 소위 단락-회로(short-circuit) 연산자입니다: 인자들은 왼쪽에서 오른쪽으로 값이 구해지고, 결과가 결정되자마자 값 구하기는 중단됩니다. 예를 들어, A 와 C 가 참이고 B 가 거짓이면, A and B and C 는 표현식 C 의 값을 구하지 않습니다. 논리값이 아닌 일반 값으로 사용될 때, 단락-회로 연산자의 반환 값은 마지막으로 값이 구해진 인자입니다.

비교의 결과나 다른 논리 표현식의 결과를 변수에 대입할 수 있습니다. 예를 들어,

>>> string1, string2, string3 = '', 'Trondheim', 'Hammer Dance'
>>> non_null = string1 or string2 or string3
>>> non_null
'Trondheim'

파이썬에서, C와는 달리, 표현식 안에서의 대입은 바다코끼리 연산자 :=를 사용하여 명시적으로 수행해야 합니다. C 프로그램에서 흔히 마주치는 부류의 문제들을 회피하도록 합니다: == 를 사용할 표현식에 = 를 입력하는 실수.

5.8. 시퀀스와 다른 형들을 비교하기

시퀀스 객체들은 보통 같은 시퀀스 형의 다른 객체들과 비교될 수 있습니다. 비교는 사전식 순서를 사용합니다: 먼저 첫 두 항목을 비교해서 다르면 이것이 비교의 결과를 결정합니다; 같으면, 다음 두 항목을 비교하고, 이런 식으로 어느 한 시퀀스가 소진될 때까지 계속합니다. 만약 비교되는 두 항목 자체가 같은 형의 시퀀스면, 사전식 비교가 재귀적으로 수행됩니다. 두 시퀀스의 모든 항목이 같다고 비교되면, 시퀀스들은 같은 것으로 취급됩니다. 한 시퀀스가 다른 하나의 머리 부분 서브 시퀀스면, 짧은 시퀀스가 작은 것입니다. 문자열의 사전식 배열은 개별 문자들의 순서를 정하는데 유니코드 코드 포인트 숫자를 사용합니다. 같은 형의 시퀀스들 간의 비교의 몇 가지 예는 이렇습니다:

(1, 2, 3)              < (1, 2, 4)
[1, 2, 3]              < [1, 2, 4]
'ABC' < 'C' < 'Pascal' < 'Python'
(1, 2, 3, 4)           < (1, 2, 4)
(1, 2)                 < (1, 2, -1)
(1, 2, 3)             == (1.0, 2.0, 3.0)
(1, 2, ('aa', 'ab'))   < (1, 2, ('abc', 'a'), 4)

서로 다른 형의 객체들을 < 나 > 로 비교하는 것은, 그 객체들이 적절한 비교 메서드들을 갖고 있을 때만 허락된다는 것에 유의하세요. 예를 들어, 서로 다른 숫자 형들은 그들의 숫자 값에 따라 비교됩니다. 그래서 0은 0.0과 같고, 등등. 그렇지 않으면, 임의의 순서를 제공하는 대신, 인터프리터는 TypeError 를 일으킵니다.

각주

[1]

다른 언어들에서는 가변 객체를 돌려주기도 하는데, d->insert("a")->remove("b")->sort(); 와 같은 메서드 연쇄를 허락합니다.

6. 모듈

파이썬 인터프리터를 종료한 후에 다시 들어가면, 여러분이 만들었던 정의들이 사라집니다 (함수나 변수들). 그래서, 좀 긴 프로그램을 쓰고자 한다면, 대신 인터프리터 입력을 편집기를 사용해서 준비한 후에 그 파일을 입력으로 사용해서 실행하는 것이 좋습니다. 이렇게 하는 것을 스크립트 를 만든다고 합니다. 프로그램이 길어짐에 따라, 유지를 쉽게 하려고 여러 개의 파일로 나누고 싶을 수 있습니다. 여러 프로그램에서 썼던 편리한 함수를 각 프로그램에 정의를 복사하지 않고도 사용하고 싶을 수도 있습니다.

이런 것을 지원하기 위해, 파이썬은 정의들을 파일에 넣고 스크립트나 인터프리터의 대화형 모드에서 사용할 수 있는 방법을 제공합니다. 그런 파일을 모듈 이라고 부릅니다; 모듈로부터 정의들이 다른 모듈이나 메인 모듈로 임포트 될 수 있습니다 (메인 모듈은 최상위 수준에서 실행되는 스크립트나 계산기 모드에서 액세스하는 변수들의 컬렉션입니다).

모듈은 파이썬 정의와 문장들을 담고 있는 파일입니다. 파일의 이름은 모듈 이름에 확장자 .py 를 붙입니다. 모듈 내에서, 모듈의 이름은 전역 변수 __name__ 으로 제공됩니다. 예를 들어, 여러분이 좋아하는 편집기로 fibo.py 라는 이름의 파일을 현재 디렉터리에 만들고 다음과 같은 내용으로 채웁니다:

# Fibonacci numbers module

def fib(n):    # write Fibonacci series up to n
    a, b = 0, 1
    while a < n:
        print(a, end=' ')
        a, b = b, a+b
    print()

def fib2(n):   # return Fibonacci series up to n
    result = []
    a, b = 0, 1
    while a < n:
        result.append(a)
        a, b = b, a+b
    return result

이제 파이썬 인터프리터에 들어가서 이 모듈을 다음과 같은 명령으로 임포트 합니다:

>>> import fibo

This does not add the names of the functions defined in fibo directly to the current namespace (see 파이썬 스코프와 이름 공간 for more details); it only adds the module name fibo there. Using the module name you can access the functions:

>>> fibo.fib(1000)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987
>>> fibo.fib2(100)
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
>>> fibo.__name__
'fibo'

함수를 자주 사용할 거라면 지역 이름으로 대입할 수 있습니다:

>>> fib = fibo.fib
>>> fib(500)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

6.1. 모듈 더 보기

모듈은 함수 정의뿐만 아니라 실행 가능한 문장들도 포함할 수 있습니다. 이 문장들은 모듈을 초기화하는 데 사용됩니다. 이것들은 임포트 문에서 모듈 이름이 처음 등장할 때만 실행됩니다. [1] (이것들은 파일이 스크립트로 실행될 때도 실행됩니다.)

Each module has its own private namespace, which is used as the global namespace by all functions defined in the module. Thus, the author of a module can use global variables in the module without worrying about accidental clashes with a user’s global variables. On the other hand, if you know what you are doing you can touch a module’s global variables with the same notation used to refer to its functions, modname.itemname.

Modules can import other modules. It is customary but not required to place all import statements at the beginning of a module (or script, for that matter). The imported module names, if placed at the top level of a module (outside any functions or classes), are added to the module’s global namespace.

There is a variant of the import statement that imports names from a module directly into the importing module’s namespace. For example:

>>> from fibo import fib, fib2
>>> fib(500)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

This does not introduce the module name from which the imports are taken in the local namespace (so in the example, fibo is not defined).

모듈이 정의하는 모든 이름을 임포트하는 변종도 있습니다:

>>> from fibo import *
>>> fib(500)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

이것은 밑줄 (_) 로 시작하는 것들을 제외한 모든 이름을 임포트 합니다. 대부분 파이썬 프로그래머들은 이 기능을 사용하지 않는데, 인터프리터로 알려지지 않은 이름들의 집합을 도입하게 되어, 여러분이 이미 정의한 것들을 가리게 될 수 있기 때문입니다.

일반적으로 모듈이나 패키지에서 * 를 임포트하는 것은 눈살을 찌푸리게 한다는 것에 유의하세요, 종종 읽기에 편하지 않은 코드를 만들기 때문입니다. 하지만, 대화형 세션에서 입력을 줄이고자 사용하는 것은 상관없습니다.

모듈 이름 다음에 as 가 올 경우, as 다음의 이름을 임포트한 모듈에 직접 연결합니다.

>>> import fibo as fib
>>> fib.fib(500)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

이것은 import fibo 가하는 것과 같은 방식으로 모듈을 임포트 하는데, 유일한 차이점은 그 모듈을 fib 라는 이름으로 사용할 수 있다는 것입니다.

from을 써서 비슷한 효과를 낼 때도 사용할 수 있습니다:

>>> from fibo import fib as fibonacci
>>> fibonacci(500)
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

참고

효율성의 이유로, 각 모듈은 인터프리터 세션마다 한 번만 임포트됩니다. 그래서, 여러분이 모듈을 수정하면, 인터프리터를 다시 시작시켜야 합니다 — 또는, 대화형으로 시험하는 모듈이 하나뿐이라면, importlib.reload() 를 사용하세요. 예를 들어, import importlib; importlib.reload(modulename).

6.1.1. 모듈을 스크립트로 실행하기

여러분이 파이썬 모듈을 이렇게 실행하면

python fibo.py <arguments>

모듈에 있는 코드는, 그것을 임포트할 때처럼 실행됩니다. 하지만 __name__ 은 "__main__" 로 설정됩니다. 이것은, 이 코드를 모듈의 끝에 붙여서:

if __name__ == "__main__":
    import sys
    fib(int(sys.argv[1]))

파일을 임포트할 수 있는 모듈뿐만 아니라 스크립트로도 사용할 수 있도록 만들 수 있음을 의미하는데, 오직 모듈이 “메인” 파일로 실행될 때만 명령행을 파싱하는 코드가 실행되기 때문입니다:

$ python fibo.py 50
0 1 1 2 3 5 8 13 21 34

모듈이 임포트될 때, 코드는 실행되지 않습니다:

>>> import fibo
>>>

이것은 종종 모듈에 대한 편리한 사용자 인터페이스를 제공하거나 테스트 목적으로 사용됩니다 (모듈을 스크립트로 실행하면 테스트 스위트를 실행하기).

6.1.2. 모듈 검색 경로

When a module named spam is imported, the interpreter first searches for a built-in module with that name. These module names are listed in sys.builtin_module_names. If not found, it then searches for a file named spam.py in a list of directories given by the variable sys.path. sys.path is initialized from these locations:

입력 스크립트를 포함하는 디렉터리 (또는 파일이 지정되지 않았을 때는 현재 디렉터리).

PYTHONPATH (디렉터리 이름들의 목록, 셸 변수 PATH 와 같은 문법).

The installation-dependent default (by convention including a site-packages directory, handled by the site module).

More details are at The initialization of the sys.path module search path.

참고

심볼릭 링크를 지원하는 파일 시스템에서, 입력 스크립트를 포함하는 디렉터리는 심볼릭 링크를 변환한 후에 계산됩니다. 다른 말로, 심볼릭 링크를 포함하는 디렉터리는 모듈 검색 경로에 포함되지 않습니다.

초기화 후에, 파이썬 프로그램은 sys.path 를 수정할 수 있습니다. 스크립트를 포함하는 디렉터리는 검색 경로의 처음에, 표준 라이브러리 경로의 앞에 놓입니다. 이것은 같은 이름일 경우 라이브러리 디렉터리에 있는 것 대신 스크립트를 포함하는 디렉터리의 것이 로드된다는 뜻입니다. 이 치환이 의도된 것이 아니라면 에러입니다. 더 자세한 정보는 표준 모듈들 을 보세요.

6.1.3. “컴파일된” 파이썬 파일

모듈 로딩을 빠르게 하려고, 파이썬은 __pycache__ 디렉터리에 각 모듈의 컴파일된 버전을 module.version.pyc 라는 이름으로 캐싱합니다. version 은 컴파일된 파일의 형식을 지정합니다; 일반적으로 파이썬의 버전 번호를 포함합니다. 예를 들어, CPython 배포 3.3 에서 spam.py 의 컴파일된 버전은 __pycache__/spam.cpython-33.pyc 로 캐싱 됩니다. 이 명명법은 서로 다른 파이썬 배포와 버전의 컴파일된 모듈들이 공존할 수 있도록 합니다.

파이썬은 소스의 수정 시간을 컴파일된 버전과 비교해서 시효가 지나 다시 컴파일해야 하는지 검사합니다. 이것은 완전히 자동화된 과정입니다. 또한, 컴파일된 모듈은 플랫폼 독립적이기 때문에, 같은 라이브러리를 서로 다른 아키텍처를 갖는 시스템들에서 공유할 수 있습니다.

파이썬은 두 가지 상황에서 캐시를 검사하지 않습니다. 첫째로, 명령행에서 직접 로드되는 모듈들은 항상 재컴파일하고 그 결과를 저장하지 않습니다. 둘째로, 소스 모듈이 없으면 캐시를 검사하지 않습니다. 소스 없는 (컴파일된 파일만 있는) 배포를 지원하려면, 컴파일된 모듈이 소스 디렉터리에 있어야 하고, 소스 모듈이 없어야 합니다.

전문가를 위한 몇 가지 팁

컴파일된 모듈의 크기를 줄이려면 파이썬 명령에 -O 나 -OO 스위치를 사용할 수 있습니다. -O 스위치는 assert 문을 제거하고, -OO 스위치는 assert 문과 __doc__ 문자열을 모두 제거합니다. 어떤 프로그램들은 이것들에 의존하기 때문에, 무엇을 하고 있는지 아는 경우만 이 옵션을 사용해야 합니다. “최적화된” 모듈은 opt- 태그를 갖고, 보통 더 작습니다. 미래의 배포에서는 최적화의 효과가 변경될 수 있습니다.

.py 파일에서 읽을 때보다 .pyc 파일에서 읽을 때 프로그램이 더 빨리 실행되지는 않습니다; .pyc 파일에서 더 빨라지는 것은 로드되는 속도뿐입니다.

모듈 compileall 은 디렉터리에 있는 모든 모듈의 .pyc 파일들을 만들 수 있습니다.

이 절차에 대한 더 자세한 정보, 결정들의 순서도를 포함합니다, 는 PEP 3147 [https://peps.python.org/pep-3147/] 에 나옵니다.

6.2. 표준 모듈들

파이썬은 표준 모듈들의 라이브러리가 함께 오는데, 별도의 문서 파이썬 라이브러리 레퍼런스 (이후로는 “라이브러리 레퍼런스”) 에서 설명합니다. 어떤 모듈들은 인터프리터에 내장됩니다; 이것들은 언어의 핵심적인 부분은 아니지만 그런데도 내장된 연산들에 대한 액세스를 제공하는데, 효율이나 시스템 호출과 같은 운영 체제 기본 요소들에 대한 액세스를 제공하기 위함입니다. 그런 모듈들의 집합은 설정 옵션인데 기반 플랫폼 의존적입니다. 예를 들어, winreg 모듈은 윈도우 시스템에서만 제공됩니다. 특별한 모듈 하나는 주목을 받을 필요가 있습니다: sys. 모든 파이썬 인터프리터에 내장됩니다. 변수 sys.ps1 와 sys.ps2 는 기본과 보조 프롬프트로 사용되는 문자열을 정의합니다:

>>> import sys
>>> sys.ps1
'>>> '
>>> sys.ps2
'... '
>>> sys.ps1 = 'C> '
C> print('Yuck!')
Yuck!
C>

이 두 개의 변수들은 인터프리터가 대화형 모드일 때만 정의됩니다.

변수 sys.path 는 인터프리터의 모듈 검색 경로를 결정하는 문자열들의 리스트입니다. 환경 변수 PYTHONPATH 에서 취한 기본 경로나, PYTHONPATH 가 설정되지 않는 경우 내장 기본값으로 초기화됩니다. 표준 리스트 연산을 사용해서 수정할 수 있습니다:

>>> import sys
>>> sys.path.append('/ufs/guido/lib/python')

6.3. dir() 함수

내장 함수 dir() 은 모듈이 정의하는 이름들을 찾는 데 사용됩니다. 문자열들의 정렬된 리스트를 돌려줍니다:

>>> import fibo, sys
>>> dir(fibo)
['__name__', 'fib', 'fib2']
>>> dir(sys)
['__breakpointhook__', '__displayhook__', '__doc__', '__excepthook__',
 '__interactivehook__', '__loader__', '__name__', '__package__', '__spec__',
 '__stderr__', '__stdin__', '__stdout__', '__unraisablehook__',
 '_clear_type_cache', '_current_frames', '_debugmallocstats', '_framework',
 '_getframe', '_git', '_home', '_xoptions', 'abiflags', 'addaudithook',
 'api_version', 'argv', 'audit', 'base_exec_prefix', 'base_prefix',
 'breakpointhook', 'builtin_module_names', 'byteorder', 'call_tracing',
 'callstats', 'copyright', 'displayhook', 'dont_write_bytecode', 'exc_info',
 'excepthook', 'exec_prefix', 'executable', 'exit', 'flags', 'float_info',
 'float_repr_style', 'get_asyncgen_hooks', 'get_coroutine_origin_tracking_depth',
 'getallocatedblocks', 'getdefaultencoding', 'getdlopenflags',
 'getfilesystemencodeerrors', 'getfilesystemencoding', 'getprofile',
 'getrecursionlimit', 'getrefcount', 'getsizeof', 'getswitchinterval',
 'gettrace', 'hash_info', 'hexversion', 'implementation', 'int_info',
 'intern', 'is_finalizing', 'last_traceback', 'last_type', 'last_value',
 'maxsize', 'maxunicode', 'meta_path', 'modules', 'path', 'path_hooks',
 'path_importer_cache', 'platform', 'prefix', 'ps1', 'ps2', 'pycache_prefix',
 'set_asyncgen_hooks', 'set_coroutine_origin_tracking_depth', 'setdlopenflags',
 'setprofile', 'setrecursionlimit', 'setswitchinterval', 'settrace', 'stderr',
 'stdin', 'stdout', 'thread_info', 'unraisablehook', 'version', 'version_info',
 'warnoptions']

인자가 없으면, dir() 는 현재 정의한 이름들을 나열합니다:

>>> a = [1, 2, 3, 4, 5]
>>> import fibo
>>> fib = fibo.fib
>>> dir()
['__builtins__', '__name__', 'a', 'fib', 'fibo', 'sys']

모든 형의 이름을 나열한다는 것에 유의해야 합니다: 변수, 모듈, 함수, 등등.

dir() 은 내장 함수와 변수들의 이름을 나열하지 않습니다. 그것들의 목록을 원한다면, 표준 모듈 builtins 에 정의되어 있습니다:

>>> import builtins
>>> dir(builtins)
['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException',
 'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning',
 'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError',
 'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning',
 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False',
 'FileExistsError', 'FileNotFoundError', 'FloatingPointError',
 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError',
 'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError',
 'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError',
 'MemoryError', 'NameError', 'None', 'NotADirectoryError', 'NotImplemented',
 'NotImplementedError', 'OSError', 'OverflowError',
 'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError',
 'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning',
 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError',
 'SystemExit', 'TabError', 'TimeoutError', 'True', 'TypeError',
 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError',
 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning',
 'ValueError', 'Warning', 'ZeroDivisionError', '_', '__build_class__',
 '__debug__', '__doc__', '__import__', '__name__', '__package__', 'abs',
 'all', 'any', 'ascii', 'bin', 'bool', 'bytearray', 'bytes', 'callable',
 'chr', 'classmethod', 'compile', 'complex', 'copyright', 'credits',
 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'exec', 'exit',
 'filter', 'float', 'format', 'frozenset', 'getattr', 'globals', 'hasattr',
 'hash', 'help', 'hex', 'id', 'input', 'int', 'isinstance', 'issubclass',
 'iter', 'len', 'license', 'list', 'locals', 'map', 'max', 'memoryview',
 'min', 'next', 'object', 'oct', 'open', 'ord', 'pow', 'print', 'property',
 'quit', 'range', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice',
 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'vars',
 'zip']

6.4. 패키지

Packages are a way of structuring Python’s module namespace by using “dotted module names”. For example, the module name A.B designates a submodule named B in a package named A. Just like the use of modules saves the authors of different modules from having to worry about each other’s global variable names, the use of dotted module names saves the authors of multi-module packages like NumPy or Pillow from having to worry about each other’s module names.

음향 파일과 과 음향 데이터의 일관된 처리를 위한 모듈들의 컬렉션 (“패키지”) 을 설계하길 원한다고 합시다. 여러 종류의 음향 파일 형식이 있으므로 (보통 확장자로 구분됩니다, 예를 들어: .wav, .aiff, .au), 다양한 파일 형식 간의 변환을 위해 계속 늘어나는 모듈들의 컬렉션을 만들고 유지할 필요가 있습니다. 또한, 음향 데이터에 적용하고자 하는 많은 종류의 연산들도 있으므로 (믹싱, 에코 넣기, 이퀄라이저 기능 적용, 인공적인 스테레오 효과 만들기와 같은), 이 연산들을 수행하기 위한 모듈들을 끊임없이 작성하게 될 것입니다. 패키지를 이렇게 구성해 볼 수 있습니다 (계층적 파일 시스템으로 표현했습니다):

sound/                          Top-level package
      __init__.py               Initialize the sound package
      formats/                  Subpackage for file format conversions
              __init__.py
              wavread.py
              wavwrite.py
              aiffread.py
              aiffwrite.py
              auread.py
              auwrite.py
              ...
      effects/                  Subpackage for sound effects
              __init__.py
              echo.py
              surround.py
              reverse.py
              ...
      filters/                  Subpackage for filters
              __init__.py
              equalizer.py
              vocoder.py
              karaoke.py
              ...

패키지를 임포트할 때, 파이썬은 sys.path 에 있는 디렉터리들을 검색하면서 패키지 서브 디렉터리를 찾습니다.

The __init__.py files are required to make Python treat directories containing the file as packages (unless using a namespace package, a relatively advanced feature). This prevents directories with a common name, such as string, from unintentionally hiding valid modules that occur later on the module search path. In the simplest case, __init__.py can just be an empty file, but it can also execute initialization code for the package or set the __all__ variable, described later.

패키지 사용자는 패키지로부터 개별 모듈을 임포트할 수 있습니다, 예를 들어:

import sound.effects.echo

This loads the submodule sound.effects.echo. It must be referenced with its full name.

sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)

서브 모듈을 임포트하는 다른 방법은 이렇습니다:

from sound.effects import echo

This also loads the submodule echo, and makes it available without its package prefix, so it can be used as follows:

echo.echofilter(input, output, delay=0.7, atten=4)

또 다른 방법은 원하는 함수나 변수를 직접 임포트하는 것입니다:

from sound.effects.echo import echofilter

Again, this loads the submodule echo, but this makes its function echofilter() directly available:

echofilter(input, output, delay=0.7, atten=4)

from package import item 를 사용할 때, item은 패키지의 서브 모듈 (또는 서브 패키지)일 수도 있고 함수, 클래스, 변수 등 패키지에 정의된 다른 이름들일 수도 있음에 유의하세요. import 문은 먼저 item이 패키지에 정의되어 있는지 검사하고, 그렇지 않으면 모듈이라고 가정하고 로드를 시도합니다. 찾지 못한다면, ImportError 예외를 일으킵니다.

이에 반하여, import item.subitem.subsubitem 와 같은 문법을 사용할 때, 마지막 것을 제외한 각 항목은 반드시 패키지여야 합니다; 마지막 항목은 모듈이나 패키지가 될 수 있지만, 앞의 항목에서 정의된 클래스, 함수, 변수 등이 될 수는 없습니다.

6.4.1. 패키지에서 * 임포트 하기

이제 from sound.effects import * 라고 쓰면 어떻게 될까? 이상적으로는, 어떻게든 파일 시스템에서 패키지에 어떤 모듈들이 들어있는지 찾은 다음, 그것들 모두를 임포트 하기를 원할 것입니다. 이렇게 하는 데는 시간이 오래 걸리고 서브 모듈을 임포트 함에 따라 어떤 서브 모듈을 명시적으로 임포트할 경우만 일어나야만 하는 원하지 않는 부수적 효과가 발생할 수 있습니다.

유일한 해결책은 패키지 저자가 패키지의 색인을 명시적으로 제공하는 것입니다. import 문은 다음과 같은 관례가 있습니다: 패키지의 __init__.py 코드가 __all__ 이라는 이름의 목록을 제공하면, 이것을 from package import * 를 만날 때 임포트 해야만 하는 모듈 이름들의 목록으로 받아들입니다. 새 버전의 패키지를 출시할 때 이 목록을 최신 상태로 유지하는 것은 패키지 저자의 책임입니다. 패키지 저자가 패키지에서 * 를 임포트하는 용도가 없다고 판단한다면, 이것을 지원하지 않기로 할 수도 있습니다. 예를 들어, 파일 sound/effects/__init__.py 는 다음과 같은 코드를 포함할 수 있습니다:

__all__ = ["echo", "surround", "reverse"]

This would mean that from sound.effects import * would import the three named submodules of the sound.effects package.

Be aware that submodules might become shadowed by locally defined names. For example, if you added a reverse function to the sound/effects/__init__.py file, the from sound.effects import * would only import the two submodules echo and surround, but not the reverse submodule, because it is shadowed by the locally defined reverse function:

__all__ = [
    "echo",      # refers to the 'echo.py' file
    "surround",  # refers to the 'surround.py' file
    "reverse",   # !!! refers to the 'reverse' function now !!!
]

def reverse(msg: str):  # <-- this name shadows the 'reverse.py' submodule
    return msg[::-1]    #     in the case of a 'from sound.effects import *'

If __all__ is not defined, the statement from sound.effects import * does not import all submodules from the package sound.effects into the current namespace; it only ensures that the package sound.effects has been imported (possibly running any initialization code in __init__.py) and then imports whatever names are defined in the package. This includes any names defined (and submodules explicitly loaded) by __init__.py. It also includes any submodules of the package that were explicitly loaded by previous import statements. Consider this code:

import sound.effects.echo
import sound.effects.surround
from sound.effects import *

In this example, the echo and surround modules are imported in the current namespace because they are defined in the sound.effects package when the from...import statement is executed. (This also works when __all__ is defined.)

설사 어떤 모듈이 import * 를 사용할 때 특정 패턴을 따르는 이름들만 익스포트 하도록 설계되었다 하더라도, 프로덕션 코드에서는 여전히 좋지 않은 사례로 여겨집니다.

from package import specific_submodule 을 사용하는데 잘못된 것은 없다는 것을 기억하세요! 사실, 임포트하는 모듈이 다른 패키지에서 같은 이름의 서브 모듈을 사용할 필요가 없는 한 권장되는 표기법입니다.

6.4.2. 패키지 내부 간의 참조

When packages are structured into subpackages (as with the sound package in the example), you can use absolute imports to refer to submodules of siblings packages. For example, if the module sound.filters.vocoder needs to use the echo module in the sound.effects package, it can use from sound.effects import echo.

You can also write relative imports, with the from module import name form of import statement. These imports use leading dots to indicate the current and parent packages involved in the relative import. From the surround module for example, you might use:

from . import echo
from .. import formats
from ..filters import equalizer

상대 임포트가 현재 모듈의 이름에 기반을 둔다는 것에 주의하세요. 메인 모듈의 이름은 항상 "__main__" 이기 때문에, 파이썬 응용 프로그램의 메인 모듈로 사용될 목적의 모듈들은 반드시 절대 임포트를 사용해야 합니다.

6.4.3. 여러 디렉터리에 있는 패키지

Packages support one more special attribute, __path__. This is initialized to be a sequence of strings containing the name of the directory holding the package’s __init__.py before the code in that file is executed. This variable can be modified; doing so affects future searches for modules and subpackages contained in the package.

이 기능이 자주 필요하지는 않지만, 패키지에서 발견되는 모듈의 집합을 확장하는 데 사용됩니다.

각주

[1]

In fact function definitions are also ‘statements’ that are ‘executed’; the execution of a module-level function definition adds the function name to the module’s global namespace.

7. 입력과 출력

프로그램의 출력을 표현하는 여러 가지 방법이 있습니다; 사람이 일기에 적합한 형태로 데이터를 인쇄할 수도 있고, 나중에 사용하기 위해 파일에 쓸 수도 있습니다. 이 장에서는 몇 가지 가능성을 논합니다.

7.1. 장식적인 출력 포매팅

So far we’ve encountered two ways of writing values: expression statements and the print() function. (A third way is using the write() method of file objects; the standard output file can be referenced as sys.stdout. See the Library Reference for more information on this.)

종종 단순히 스페이스로 구분된 값을 인쇄하는 것보다 출력 형식을 더 많이 제어해야 하는 경우가 있습니다. 출력을 포맷하는 데는 여러 가지 방법이 있습니다.

포맷 문자열 리터럴을 사용하려면, 시작 인용 부호 또는 삼중 인용 부호 앞에 f 또는 F 를 붙여 문자열을 시작하십시오. 이 문자열 안에서, { 및 } 문자 사이에, 변수 또는 리터럴 값을 참조할 수 있는 파이썬 표현식을 작성할 수 있습니다.

>>> year = 2016
>>> event = 'Referendum'
>>> f'Results of the {year} {event}'
'Results of the 2016 Referendum'

The str.format() method of strings requires more manual effort. You’ll still use { and } to mark where a variable will be substituted and can provide detailed formatting directives, but you’ll also need to provide the information to be formatted. In the following code block there are two examples of how to format variables:

>>> yes_votes = 42_572_654
>>> total_votes = 85_705_149
>>> percentage = yes_votes / total_votes
>>> '{:-9} YES votes  {:2.2%}'.format(yes_votes, percentage)
' 42572654 YES votes  49.67%'

Notice how the yes_votes are padded with spaces and a negative sign only for negative numbers. The example also prints percentage multiplied by 100, with 2 decimal places and followed by a percent sign (see 포맷 명세 미니 언어 for details).

마지막으로, 문자열 슬라이싱 및 이어붙이기 연산을 사용하여 상상할 수 있는 모든 배치를 만듦으로써, 모든 문자열 처리를 스스로 수행할 수 있습니다. 문자열형에는 주어진 열 너비로 문자열을 채우는 데 유용한 연산을 수행하는 몇 가지 메서드가 있습니다.

장식적인 출력이 필요하지 않고 단지 디버깅을 위해 일부 변수를 빠르게 표시하려면, repr() 또는 str() 함수를 사용하여 모든 값을 문자열로 변환할 수 있습니다.

str() 함수는 어느 정도 사람이 읽기에 적합한 형태로 값의 표현을 돌려주게 되어있습니다. 반면에 repr() 은 인터프리터에 의해 읽힐 수 있는 형태를 만들게 되어있습니다 (또는 그렇게 표현할 수 있는 문법이 없으면 SyntaxError 를 일으키도록 구성됩니다). 사람이 소비하기 위한 특별한 표현이 없는 객체의 경우, str() 는 repr() 과 같은 값을 돌려줍니다. 많은 값, 숫자들이나 리스트와 딕셔너리와 같은 구조들, 은 두 함수를 쓸 때 같은 표현을 합니다. 특별히, 문자열은 두 가지 표현을 합니다.

몇 가지 예를 듭니다:

>>> s = 'Hello, world.'
>>> str(s)
'Hello, world.'
>>> repr(s)
"'Hello, world.'"
>>> str(1/7)
'0.14285714285714285'
>>> x = 10 * 3.25
>>> y = 200 * 200
>>> s = 'The value of x is ' + repr(x) + ', and y is ' + repr(y) + '...'
>>> print(s)
The value of x is 32.5, and y is 40000...
>>> # The repr() of a string adds string quotes and backslashes:
>>> hello = 'hello, world\n'
>>> hellos = repr(hello)
>>> print(hellos)
'hello, world\n'
>>> # The argument to repr() may be any Python object:
>>> repr((x, y, ('spam', 'eggs')))
"(32.5, 40000, ('spam', 'eggs'))"

string 모듈에는 문자열에 값을 치환하는 또 다른 방법을 제공하는 Template 클래스가 포함되어 있습니다. $x와 같은 자리 표시자를 사용하고 이것들을 딕셔너리에서 오는 값으로 치환하지만, 포매팅에 대한 제어를 훨씬 덜 제공합니다.

7.1.1. 포맷 문자열 리터럴

포맷 문자열 리터럴(간단히 f-문자열이라고도 합니다)은 문자열에 f 또는 F 접두어를 붙이고 표현식을 {expression}로 작성하여 문자열에 파이썬 표현식의 값을 삽입할 수 있게 합니다.

선택적인 포맷 지정자가 표현식 뒤에 올 수 있습니다. 이것으로 값이 포맷되는 방식을 더 정교하게 제어할 수 있습니다. 다음 예는 원주율을 소수점 이하 세 자리로 반올림합니다.

>>> import math
>>> print(f'The value of pi is approximately {math.pi:.3f}.')
The value of pi is approximately 3.142.

':' 뒤에 정수를 전달하면 해당 필드의 최소 문자 폭이 됩니다. 열을 줄 맞춤할 때 편리합니다.

>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678}
>>> for name, phone in table.items():
...     print(f'{name:10} ==> {phone:10d}')
...
Sjoerd     ==>       4127
Jack       ==>       4098
Dcab       ==>       7678

다른 수정자를 사용하면 포맷되기 전에 값을 변환할 수 있습니다. '!a'는 ascii()를, '!s'는 str()을, '!r'는 repr()을 적용합니다.:

>>> animals = 'eels'
>>> print(f'My hovercraft is full of {animals}.')
My hovercraft is full of eels.
>>> print(f'My hovercraft is full of {animals!r}.')
My hovercraft is full of 'eels'.

The = specifier can be used to expand an expression to the text of the expression, an equal sign, then the representation of the evaluated expression:

>>> bugs = 'roaches'
>>> count = 13
>>> area = 'living room'
>>> print(f'Debugging {bugs=} {count=} {area=}')
Debugging bugs='roaches' count=13 area='living room'

See self-documenting expressions for more information on the = specifier. For a reference on these format specifications, see the reference guide for the 포맷 명세 미니 언어.

7.1.2. 문자열 format() 메서드

str.format() 메서드의 기본적인 사용법은 이런 식입니다:

>>> print('We are the {} who say "{}!"'.format('knights', 'Ni'))
We are the knights who say "Ni!"

중괄호와 그 안에 있는 문자들 (포맷 필드라고 부른다) 은 str.format() 메서드로 전달된 객체들로 치환됩니다. 중괄호 안의 숫자는 str.format() 메서드로 전달된 객체들의 위치를 가리키는데 사용될 수 있습니다.

>>> print('{0} and {1}'.format('spam', 'eggs'))
spam and eggs
>>> print('{1} and {0}'.format('spam', 'eggs'))
eggs and spam

str.format() 메서드에 키워드 인자가 사용되면, 그 값들은 인자의 이름을 사용해서 지정할 수 있습니다.

>>> print('This {food} is {adjective}.'.format(
...       food='spam', adjective='absolutely horrible'))
This spam is absolutely horrible.

위치와 키워드 인자를 자유롭게 조합할 수 있습니다:

>>> print('The story of {0}, {1}, and {other}.'.format('Bill', 'Manfred',
...                                                    other='Georg'))
The story of Bill, Manfred, and Georg.

나누고 싶지 않은 정말 긴 포맷 문자열이 있을 때, 포맷할 변수들을 위치 대신에 이름으로 지정할 수 있다면 좋을 것입니다. 간단히 딕셔너리를 넘기고 키를 액세스하는데 대괄호 '[]' 를 사용하면 됩니다.

>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
>>> print('Jack: {0[Jack]:d}; Sjoerd: {0[Sjoerd]:d}; '
...       'Dcab: {0[Dcab]:d}'.format(table))
Jack: 4098; Sjoerd: 4127; Dcab: 8637678

This could also be done by passing the table dictionary as keyword arguments with the ** notation.

>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
>>> print('Jack: {Jack:d}; Sjoerd: {Sjoerd:d}; Dcab: {Dcab:d}'.format(**table))
Jack: 4098; Sjoerd: 4127; Dcab: 8637678

This is particularly useful in combination with the built-in function vars(), which returns a dictionary containing all local variables:

>>> table = {k: str(v) for k, v in vars().items()}
>>> message = " ".join([f'{k}: ' + '{' + k +'};' for k in table.keys()])
>>> print(message.format(**table))
__name__: __main__; __doc__: None; __package__: None; __loader__: ...

As an example, the following lines produce a tidily aligned set of columns giving integers and their squares and cubes:

>>> for x in range(1, 11):
...     print('{0:2d} {1:3d} {2:4d}'.format(x, x*x, x*x*x))
...
 1   1    1
 2   4    8
 3   9   27
 4  16   64
 5  25  125
 6  36  216
 7  49  343
 8  64  512
 9  81  729
10 100 1000

str.format() 를 사용한 문자열 포매팅의 완전한 개요는 포맷 문자열 문법 을 보세요.

7.1.3. 수동 문자열 포매팅

여기 같은 제곱수와 세제곱수 표를 수동으로 포매팅했습니다:

>>> for x in range(1, 11):
...     print(repr(x).rjust(2), repr(x*x).rjust(3), end=' ')
...     # Note use of 'end' on previous line
...     print(repr(x*x*x).rjust(4))
...
 1   1    1
 2   4    8
 3   9   27
 4  16   64
 5  25  125
 6  36  216
 7  49  343
 8  64  512
 9  81  729
10 100 1000

(print() 의 동작 방식으로 인해 각 칼럼 사이에 스페이스 하나가 추가되었음에 유의하세요: 항상 인자들 사이에 스페이스를 추가합니다.)

문자열 객체의 str.rjust() 메서드는 왼쪽에 스페이스를 채워서 주어진 폭으로 문자열을 우측 줄 맞춤합니다. 비슷한 메서드 str.ljust() 와 str.center() 도 있습니다. 이 메서드들은 어떤 것도 출력하지 않습니다, 단지 새 문자열을 돌려줍니다. 입력 문자열이 너무 길면, 자르지 않고, 변경 없이 그냥 돌려줍니다; 이것이 열 배치를 엉망으로 만들겠지만, 보통 값에 대해 거짓말을 하게 될 대안보다는 낫습니다. (정말로 잘라내기를 원한다면, 항상 슬라이스 연산을 추가할 수 있습니다, x.ljust(n)[:n] 처럼.)

다른 메서드도 있습니다, str.zfill(). 숫자 문자열의 왼쪽에 0을 채웁니다. 플러스와 마이너스 부호도 이해합니다:

>>> '12'.zfill(5)
'00012'
>>> '-3.14'.zfill(7)
'-003.14'
>>> '3.14159265359'.zfill(5)
'3.14159265359'

7.1.4. 예전의 문자열 포매팅

The % operator (modulo) can also be used for string formatting. Given format % values (where format is a string), % conversion specifications in format are replaced with zero or more elements of values. This operation is commonly known as string interpolation. For example:

>>> import math
>>> print('The value of pi is approximately %5.3f.' % math.pi)
The value of pi is approximately 3.142.

더 자세한 내용은 printf 스타일 문자열 포매팅 섹션에 나옵니다.

7.2. 파일을 읽고 쓰기

open() returns a file object, and is most commonly used with two positional arguments and one keyword argument: open(filename, mode, encoding=None)

>>> f = open('workfile', 'w', encoding="utf-8")

첫 번째 인자는 파일 이름을 담은 문자열입니다. 두 번째 인자는 파일이 사용될 방식을 설명하는 몇 개의 문자들을 담은 또 하나의 문자열입니다. mode 는 파일을 읽기만 하면 'r', 쓰기만 하면 'w' (같은 이름의 이미 존재하는 파일은 삭제됩니다) 가 되고, 'a' 는 파일을 덧붙이기 위해 엽니다; 파일에 기록되는 모든 데이터는 자동으로 끝에 붙습니다. 'r+' 는 파일을 읽고 쓰기 위해 엽니다. mode 인자는 선택적인데, 생략하면 'r' 이 가정됩니다.

Normally, files are opened in text mode, that means, you read and write strings from and to the file, which are encoded in a specific encoding. If encoding is not specified, the default is platform dependent (see open()). Because UTF-8 is the modern de-facto standard, encoding="utf-8" is recommended unless you know that you need to use a different encoding. Appending a 'b' to the mode opens the file in binary mode. Binary mode data is read and written as bytes objects. You can not specify encoding when opening file in binary mode.

텍스트 모드에서, 읽을 때의 기본 동작은 플랫폼 의존적인 줄 종료 (유닉스에서 \n, 윈도우에서 \r\n) 를 단지 \n 로 변경하는 것입니다. 텍스트 모드로 쓸 때, 기본 동작은 \n 를 다시 플랫폼 의존적인 줄 종료로 변환하는 것입니다. 이 파일 데이터에 대한 무대 뒤의 수정은 텍스트 파일의 경우는 문제가 안 되지만, JPEG 이나 EXE 파일과 같은 바이너리 데이터를 망치게 됩니다. 그런 파일을 읽고 쓸 때 바이너리 모드를 사용하도록 주의하세요.

파일 객체를 다룰 때 with 키워드를 사용하는 것은 좋은 습관입니다. 혜택은 도중 예외가 발생하더라도 스위트가 종료될 때 파일이 올바르게 닫힌다는 것입니다. with 를 사용하는 것은 동등한 try-finally 블록을 쓰는 것에 비교해 훨씬 짧기도 합니다:

>>> with open('workfile', encoding="utf-8") as f:
...     read_data = f.read()

>>> # We can check that the file has been automatically closed.
>>> f.closed
True

with 키워드를 사용하지 않으면, f.close() 를 호출해서 파일을 닫고 사용된 시스템 자원을 즉시 반납해야 합니다.

경고

with 키워드를 사용하거나 f.close()를 호출하지 않고 f.write()를 호출하면 프로그램이 성공적으로 종료되더라도 f.write()의 인자가 디스크에 완전히 기록되지 않을 수 있습니다.

파일 객체가 닫힌 후에는, with 문이나 f.close() 를 호출하는 경우 모두, 파일 객체를 사용하려는 시도는 자동으로 실패합니다.

>>> f.close()
>>> f.read()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: I/O operation on closed file.

7.2.1. 파일 객체의 매소드

이 섹션의 나머지 예들은 f 라는 파일 객체가 이미 만들어졌다고 가정합니다.

파일의 내용을 읽으려면, f.read(size) 를 호출하는데, 일정량의 데이터를 읽고 문자열 (텍스트 모드 에서) 이나 바이트열 (바이너리 모드에서) 로 돌려줍니다. size 는 선택적인 숫자 인자입니다. size 가 생략되거나 음수면 파일의 내용 전체를 읽어서 돌려줍니다; 파일의 크기가 기계의 메모리보다 두 배 크다면 여러분이 감당할 문제입니다. 그렇지 않으면 최대 size 문자(텍스트 모드에서)나 size 바이트(바이너리 모드에서)를 읽고 돌려줍니다. 파일의 끝에 도달하면, f.read() 는 빈 문자열 ('') 을 돌려줍니다.

>>> f.read()
'This is the entire file.\n'
>>> f.read()
''

f.readline() 은 파일에서 한 줄을 읽습니다; 개행 문자 (\n) 는 문자열의 끝에 보존되고, 파일이 개행문자로 끝나지 않는 때에만 파일의 마지막 줄에서만 생략됩니다. 이렇게 반환 값을 모호하지 않게 만듭니다; f.readline() 가 빈 문자열을 돌려주면, 파일의 끝에 도달한 것이지만, 빈 줄은 '\n', 즉 하나의 개행문자만을 포함하는 문자열로 표현됩니다.

>>> f.readline()
'This is the first line of the file.\n'
>>> f.readline()
'Second line of the file\n'
>>> f.readline()
''

파일에서 줄들을 읽으려면, 파일 객체에 대해 루핑할 수 있습니다. 이것은 메모리 효율적이고, 빠르며 간단한 코드로 이어집니다:

>>> for line in f:
...     print(line, end='')
...
This is the first line of the file.
Second line of the file

파일의 모든 줄을 리스트로 읽어 들이려면 list(f) 나 f.readlines() 를 쓸 수 있습니다.

f.write(string) 은 string 의 내용을 파일에 쓰고, 출력된 문자들의 개수를 돌려줍니다.

>>> f.write('This is a test\n')
15

다른 형의 객체들은 쓰기 전에 변환될 필요가 있습니다 – 문자열 (텍스트 모드에서) 이나 바이트열 객체 (바이너리 모드에서) 로 –:

>>> value = ('the answer', 42)
>>> s = str(value)  # convert the tuple to string
>>> f.write(s)
18

f.tell() 은 파일의 현재 위치를 가리키는 정수를 돌려주는데, 바이너리 모드의 경우 파일의 처음부터의 바이트 수로 표현되고 텍스트 모드의 경우는 불투명한 숫자입니다.

파일 객체의 위치를 바꾸려면, f.seek(offset, whence) 를 사용합니다. 위치는 기준점에 offset 을 더해서 계산됩니다; 기준점은 whence 인자로 선택합니다. whence 값이 0이면 파일의 처음부터 측정하고, 1이면 현재 파일 위치를 사용하고, 2 는 파일의 끝을 기준점으로 사용합니다. whence 는 생략될 수 있고, 기본값은 0이라서 파일의 처음을 기준점으로 사용합니다.

>>> f = open('workfile', 'rb+')
>>> f.write(b'0123456789abcdef')
16
>>> f.seek(5)      # Go to the 6th byte in the file
5
>>> f.read(1)
b'5'
>>> f.seek(-3, 2)  # Go to the 3rd byte before the end
13
>>> f.read(1)
b'd'

텍스트 파일에서는 (모드 문자열에 b 가 없이 열린 것들), 파일의 시작에 상대적인 위치 변경만 허락되고 (예외는 seek(0, 2) 를 사용해서 파일의 끝으로 위치를 변경하는 경우입니다), 올바른 offset 값은 f.tell() 이 돌려준 값과 0뿐입니다. 그 밖의 다른 offset 값은 정의되지 않은 결과를 낳습니다.

File objects have some additional methods, such as isatty() and truncate() which are less frequently used; consult the Library Reference for a complete guide to file objects.

7.2.2. json 으로 구조적인 데이터를 저장하기

Strings can easily be written to and read from a file. Numbers take a bit more effort, since the read() method only returns strings, which will have to be passed to a function like int(), which takes a string like '123' and returns its numeric value 123. When you want to save more complex data types like nested lists and dictionaries, parsing and serializing by hand becomes complicated.

Rather than having users constantly writing and debugging code to save complicated data types to files, Python allows you to use the popular data interchange format called JSON (JavaScript Object Notation) [https://json.org]. The standard module called json can take Python data hierarchies, and convert them to string representations; this process is called serializing. Reconstructing the data from the string representation is called deserializing. Between serializing and deserializing, the string representing the object may have been stored in a file or data, or sent over a network connection to some distant machine.

참고

JSON 형식은 데이터 교환을 위해 현대 응용 프로그램들이 자주 사용합니다. 많은 프로그래머가 이미 이것에 익숙하므로, 연동성을 위한 좋은 선택이 됩니다.

객체 x 가 있을 때, 간단한 한 줄의 코드로 그것의 JSON 문자열 표현을 볼 수 있습니다:

>>> import json
>>> x = [1, 'simple', 'list']
>>> json.dumps(x)
'[1, "simple", "list"]'

dump()라는 dumps() 함수의 변종은 객체를 텍스트 파일 로 직렬화합니다. 그래서 f 가 쓰기를 위해 열린 텍스트 파일 이면, 이렇게 할 수 있습니다:

json.dump(x, f)

To decode the object again, if f is a binary file or text file object which has been opened for reading:

x = json.load(f)

참고

JSON files must be encoded in UTF-8. Use encoding="utf-8" when opening JSON file as a text file for both of reading and writing.

이 간단한 직렬화 테크닉이 리스트와 딕셔너리를 다룰 수 있지만, 임의의 클래스 인스턴스를 JSON 으로 직렬화하기 위해서는 약간의 수고가 더 필요합니다. json 모듈의 레퍼런스는 이 방법에 대한 설명을 담고 있습니다.

더 보기

pickle - 피클 모듈

JSON 에 반해, pickle 은 임의의 복잡한 파이썬 객체들을 직렬화할 수 있는 프로토콜입니다. 파이썬에 국한되고 다른 언어로 작성된 응용 프로그램들과 통신하는데 사용될 수 없습니다. 기본적으로 안전하지 않기도 합니다: 믿을 수 없는 소스에서 온 데이터를 역 직렬화할 때, 숙련된 공격자에 의해 데이터가 조작되었다면 임의의 코드가 실행될 수 있습니다.

8. 에러와 예외

지금까지 에러 메시지가 언급되지는 않았지만, 예제들을 직접 해보았다면 아마도 몇몇 개를 보았을 것입니다. (적어도) 두 가지 구별되는 에러들이 있습니다; 문법 에러 와 예외.

8.1. 문법 에러

문법 에러는, 파싱 에러라고도 알려져 있습니다, 아마도 여러분이 파이썬을 배우고 있는 동안에는 가장 자주 만나는 종류의 불평일 것입니다:

>>> while True print('Hello world')
  File "<stdin>", line 1
    while True print('Hello world')
               ^^^^^
SyntaxError: invalid syntax

The parser repeats the offending line and displays little arrows pointing at the token in the line where the error was detected. The error may be caused by the absence of a token before the indicated token. In the example, the error is detected at the function print(), since a colon (':') is missing before it. File name and line number are printed so you know where to look in case the input came from a script.

8.2. 예외

문장이나 표현식이 문법적으로 올바르다 할지라도, 실행하려고 하면 에러를 일으킬 수 있습니다. 실행 중에 감지되는 에러들을 예외 라고 부르고 무조건 치명적이지는 않습니다: 파이썬 프로그램에서 이것들을 어떻게 다루는지 곧 배우게 됩니다. 하지만 대부분의 예외는 프로그램이 처리하지 않아서, 여기에서 볼 수 있듯이 에러 메시지를 만듭니다:

>>> 10 * (1/0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    10 * (1/0)
          ~^~
ZeroDivisionError: division by zero
>>> 4 + spam*3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    4 + spam*3
        ^^^^
NameError: name 'spam' is not defined
>>> '2' + 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    '2' + 2
    ~~~~^~~
TypeError: can only concatenate str (not "int") to str

에러 메시지의 마지막 줄은 어떤 일이 일어났는지 알려줍니다. 예외는 여러 형으로 나타나고, 형이 메시지 일부로 인쇄됩니다: 이 예에서의 형은 ZeroDivisionError, NameError, TypeError 입니다. 예외 형으로 인쇄된 문자열은 발생한 내장 예외의 이름입니다. 이것은 모든 내장 예외들의 경우는 항상 참이지만, 사용자 정의 예외의 경우는 (편리한 관례임에도 불구하고) 꼭 그럴 필요는 없습니다. 표준 예외 이름은 내장 식별자입니다 (예약 키워드가 아닙니다).

줄의 나머지 부분은 예외의 형과 원인에 기반을 둔 상세 명세를 제공합니다.

에러 메시지의 앞부분은 스택 트레이스의 형태로 예외가 일어난 위치의 문맥을 보여줍니다. 일반적으로 소스의 줄들을 나열하는 스택 트레이스를 포함하고 있습니다; 하지만, 표준 입력에서 읽어 들인 줄들은 표시하지 않습니다.

내장 예외 는 내장 예외들과 그 들의 의미를 나열하고 있습니다.

8.3. 예외 처리하기

선택한 예외를 처리하는 프로그램을 만드는 것이 가능합니다. 다음 예를 보면, 올바를 정수가 입력될 때까지 사용자에게 입력을 요청하지만, 사용자가 프로그램을 인터럽트 하는 것을 허용합니다 (Control-C 나 그 외에 운영 체제가 지원하는 것을 사용해서); 사용자가 만든 인터럽트는 KeyboardInterrupt 예외를 일으키는 형태로 나타남에 유의하세요.

>>> while True:
...     try:
...         x = int(input("Please enter a number: "))
...         break
...     except ValueError:
...         print("Oops!  That was no valid number.  Try again...")
...

try 문은 다음과 같이 동작합니다.

먼저, try 절 (try 와 except 사이의 문장들) 이 실행됩니다.

예외가 발생하지 않으면, except 절 을 건너뛰고 try 문의 실행은 종료됩니다.

If an exception occurs during execution of the try clause, the rest of the clause is skipped. Then, if its type matches the exception named after the except keyword, the except clause is executed, and then execution continues after the try/except block.

If an exception occurs which does not match the exception named in the except clause, it is passed on to outer try statements; if no handler is found, it is an unhandled exception and execution stops with an error message.

A try statement may have more than one except clause, to specify handlers for different exceptions. At most one handler will be executed. Handlers only handle exceptions that occur in the corresponding try clause, not in other handlers of the same try statement. An except clause may name multiple exceptions as a parenthesized tuple, for example:

... except (RuntimeError, TypeError, NameError):
...     pass

A class in an except clause matches exceptions which are instances of the class itself or one of its derived classes (but not the other way around — an except clause listing a derived class does not match instances of its base classes). For example, the following code will print B, C, D in that order:

class B(Exception):
    pass

class C(B):
    pass

class D(C):
    pass

for cls in [B, C, D]:
    try:
        raise cls()
    except D:
        print("D")
    except C:
        print("C")
    except B:
        print("B")

Note that if the except clauses were reversed (with except B first), it would have printed B, B, B — the first matching except clause is triggered.

When an exception occurs, it may have associated values, also known as the exception’s arguments. The presence and types of the arguments depend on the exception type.

The except clause may specify a variable after the exception name. The variable is bound to the exception instance which typically has an args attribute that stores the arguments. For convenience, builtin exception types define __str__() to print all the arguments without explicitly accessing .args.

>>> try:
...     raise Exception('spam', 'eggs')
... except Exception as inst:
...     print(type(inst))    # the exception type
...     print(inst.args)     # arguments stored in .args
...     print(inst)          # __str__ allows args to be printed directly,
...                          # but may be overridden in exception subclasses
...     x, y = inst.args     # unpack args
...     print('x =', x)
...     print('y =', y)
...
<class 'Exception'>
('spam', 'eggs')
('spam', 'eggs')
x = spam
y = eggs

The exception’s __str__() output is printed as the last part (‘detail’) of the message for unhandled exceptions.

BaseException is the common base class of all exceptions. One of its subclasses, Exception, is the base class of all the non-fatal exceptions. Exceptions which are not subclasses of Exception are not typically handled, because they are used to indicate that the program should terminate. They include SystemExit which is raised by sys.exit() and KeyboardInterrupt which is raised when a user wishes to interrupt the program.

Exception can be used as a wildcard that catches (almost) everything. However, it is good practice to be as specific as possible with the types of exceptions that we intend to handle, and to allow any unexpected exceptions to propagate on.

The most common pattern for handling Exception is to print or log the exception and then re-raise it (allowing a caller to handle the exception as well):

import sys

try:
    f = open('myfile.txt')
    s = f.readline()
    i = int(s.strip())
except OSError as err:
    print("OS error:", err)
except ValueError:
    print("Could not convert data to an integer.")
except Exception as err:
    print(f"Unexpected {err=}, {type(err)=}")
    raise

The try … except statement has an optional else clause, which, when present, must follow all except clauses. It is useful for code that must be executed if the try clause does not raise an exception. For example:

for arg in sys.argv[1:]:
    try:
        f = open(arg, 'r')
    except OSError:
        print('cannot open', arg)
    else:
        print(arg, 'has', len(f.readlines()), 'lines')
        f.close()

else 절의 사용이 try 절에 코드를 추가하는 것보다 좋은데, try … except 문에 의해 보호되고 있는 코드가 일으키지 않은 예외를 우연히 잡게 되는 것을 방지하기 때문입니다.

Exception handlers do not handle only exceptions that occur immediately in the try clause, but also those that occur inside functions that are called (even indirectly) in the try clause. For example:

>>> def this_fails():
...     x = 1/0
...
>>> try:
...     this_fails()
... except ZeroDivisionError as err:
...     print('Handling run-time error:', err)
...
Handling run-time error: division by zero

8.4. 예외 일으키기

raise 문은 프로그래머가 지정한 예외가 발생하도록 강제할 수 있게 합니다. 예를 들어:

>>> raise NameError('HiThere')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    raise NameError('HiThere')
NameError: HiThere

The sole argument to raise indicates the exception to be raised. This must be either an exception instance or an exception class (a class that derives from BaseException, such as Exception or one of its subclasses). If an exception class is passed, it will be implicitly instantiated by calling its constructor with no arguments:

raise ValueError  # shorthand for 'raise ValueError()'

만약 예외가 발생했는지는 알아야 하지만 처리하고 싶지는 않다면, 더 간단한 형태의 raise 문이 그 예외를 다시 일으킬 수 있게 합니다:

>>> try:
...     raise NameError('HiThere')
... except NameError:
...     print('An exception flew by!')
...     raise
...
An exception flew by!
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    raise NameError('HiThere')
NameError: HiThere

8.5. 예외 연쇄

If an unhandled exception occurs inside an except section, it will have the exception being handled attached to it and included in the error message:

>>> try:
...     open("database.sqlite")
... except OSError:
...     raise RuntimeError("unable to handle error")
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    open("database.sqlite")
    ~~~~^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'database.sqlite'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
    raise RuntimeError("unable to handle error")
RuntimeError: unable to handle error

To indicate that an exception is a direct consequence of another, the raise statement allows an optional from clause:

# exc must be exception instance or None.
raise RuntimeError from exc

이것은 예외를 변환할 때 유용할 수 있습니다. 예를 들면:

>>> def func():
...     raise ConnectionError
...
>>> try:
...     func()
... except ConnectionError as exc:
...     raise RuntimeError('Failed to open database') from exc
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    func()
    ~~~~^^
  File "<stdin>", line 2, in func
ConnectionError

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
    raise RuntimeError('Failed to open database') from exc
RuntimeError: Failed to open database

It also allows disabling automatic exception chaining using the from None idiom:

>>> try:
...     open('database.sqlite')
... except OSError:
...     raise RuntimeError from None
...
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
    raise RuntimeError from None
RuntimeError

연쇄 메커니즘에 대한 자세한 내용은, 내장 예외를 참조하십시오.

8.6. 사용자 정의 예외

새 예외 클래스를 만듦으로써 프로그램은 자신의 예외에 이름을 붙일 수 있습니다 (파이썬 클래스에 대한 자세한 내용은 클래스 를 보세요). 예외는 보통 직접적으로나 간접적으로 Exception 클래스를 계승합니다.

Exception classes can be defined which do anything any other class can do, but are usually kept simple, often only offering a number of attributes that allow information about the error to be extracted by handlers for the exception.

대부분의 예외는 표준 예외들의 이름들과 유사하게, “Error” 로 끝나는 이름으로 정의됩니다.

Many standard modules define their own exceptions to report errors that may occur in functions they define.

8.7. 뒷정리 동작 정의하기

try 문은 또 다른 선택적 절을 가질 수 있는데 모든 상황에 실행되어야만 하는 뒷정리 동작을 정의하는 데 사용됩니다. 예를 들어:

>>> try:
...     raise KeyboardInterrupt
... finally:
...     print('Goodbye, world!')
...
Goodbye, world!
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    raise KeyboardInterrupt
KeyboardInterrupt

finally 절이 있으면, try 문이 완료되기 전에 finally 절이 마지막 작업으로 실행됩니다. finally 절은 try 문이 예외를 생성하는지와 관계없이 실행됩니다. 다음은 예외가 발생할 때 더 복잡한 경우를 설명합니다:

try 절을 실행하는 동안 예외가 발생하면, except 절에서 예외를 처리할 수 있습니다. 예외가 except 절에서 처리되지 않으면, finally 절이 실행된 후 예외가 다시 발생합니다.

except나 else 절 실행 중에 예외가 발생할 수 있습니다. 다시, finally 절이 실행된 후 예외가 다시 발생합니다.

If the finally clause executes a break, continue or return statement, exceptions are not re-raised.

try 문이 break, continue 또는 return 문에 도달하면, finally 절은 break, continue 또는 return 문 실행 직전에 실행됩니다.

finally 절에 return 문이 포함되면, 반환 값은 try 절의 return 문이 주는 값이 아니라, finally 절의 return 문이 주는 값이 됩니다.

예를 들면:

>>> def bool_return():
...     try:
...         return True
...     finally:
...         return False
...
>>> bool_return()
False

더 복잡한 예:

>>> def divide(x, y):
...     try:
...         result = x / y
...     except ZeroDivisionError:
...         print("division by zero!")
...     else:
...         print("result is", result)
...     finally:
...         print("executing finally clause")
...
>>> divide(2, 1)
result is 2.0
executing finally clause
>>> divide(2, 0)
division by zero!
executing finally clause
>>> divide("2", "1")
executing finally clause
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    divide("2", "1")
    ~~~~~~^^^^^^^^^^
  File "<stdin>", line 3, in divide
    result = x / y
             ~~^~~
TypeError: unsupported operand type(s) for /: 'str' and 'str'

보인 바와 같이, finally 절은 모든 경우에 실행됩니다. 두 문자열을 나눠서 발생한 TypeError 는 except 절에 의해 처리되지 않고 finally 절이 실행된 후에 다시 일어납니다.

실제 세상의 응용 프로그램에서, finally 절은 외부 자원을 사용할 때, 성공적인지 아닌지와 관계없이, 그 자원을 반납하는 데 유용합니다 (파일이나 네트워크 연결 같은 것들).

8.8. 미리 정의된 뒷정리 동작들

어떤 객체들은 객체가 더 필요 없을 때 개입하는 표준 뒷정리 동작을 정의합니다. 그 객체를 사용하는 연산의 성공 여부와 관계없습니다. 파일을 열고 그 내용을 화면에 인쇄하려고 하는 다음 예를 보세요.

for line in open("myfile.txt"):
    print(line, end="")

이 코드의 문제점은 이 부분이 실행을 끝낸 뒤에도 예측할 수 없는 기간 동안 파일을 열린 채로 둔다는 것입니다. 간단한 스크립트에서는 문제가 되지 않지만, 큰 응용 프로그램에서는 문제가 될 수 있습니다. with 문은 파일과 같은 객체들이 즉시 올바르게 뒷정리 되도록 보장하는 방법을 제공합니다.

with open("myfile.txt") as f:
    for line in f:
        print(line, end="")

문장이 실행된 후에, 줄을 처리하는 데 문제가 발생하더라도, 파일 f 는 항상 닫힙니다. 파일과 같이, 미리 정의된 뒷정리 동작들을 제공하는 객체들은 그들의 설명서에서 이 사실을 설명합니다.

8.9. Raising and Handling Multiple Unrelated Exceptions

There are situations where it is necessary to report several exceptions that have occurred. This is often the case in concurrency frameworks, when several tasks may have failed in parallel, but there are also other use cases where it is desirable to continue execution and collect multiple errors rather than raise the first exception.

The builtin ExceptionGroup wraps a list of exception instances so that they can be raised together. It is an exception itself, so it can be caught like any other exception.

>>> def f():
...     excs = [OSError('error 1'), SystemError('error 2')]
...     raise ExceptionGroup('there were problems', excs)
...
>>> f()
  + Exception Group Traceback (most recent call last):
  |   File "<stdin>", line 1, in <module>
  |     f()
  |     ~^^
  |   File "<stdin>", line 3, in f
  |     raise ExceptionGroup('there were problems', excs)
  | ExceptionGroup: there were problems (2 sub-exceptions)
  +-+---------------- 1 ----------------
    | OSError: error 1
    +---------------- 2 ----------------
    | SystemError: error 2
    +------------------------------------
>>> try:
...     f()
... except Exception as e:
...     print(f'caught {type(e)}: e')
...
caught <class 'ExceptionGroup'>: e
>>>

By using except* instead of except, we can selectively handle only the exceptions in the group that match a certain type. In the following example, which shows a nested exception group, each except* clause extracts from the group exceptions of a certain type while letting all other exceptions propagate to other clauses and eventually to be reraised.

>>> def f():
...     raise ExceptionGroup(
...         "group1",
...         [
...             OSError(1),
...             SystemError(2),
...             ExceptionGroup(
...                 "group2",
...                 [
...                     OSError(3),
...                     RecursionError(4)
...                 ]
...             )
...         ]
...     )
...
>>> try:
...     f()
... except* OSError as e:
...     print("There were OSErrors")
... except* SystemError as e:
...     print("There were SystemErrors")
...
There were OSErrors
There were SystemErrors
  + Exception Group Traceback (most recent call last):
  |   File "<stdin>", line 2, in <module>
  |     f()
  |     ~^^
  |   File "<stdin>", line 2, in f
  |     raise ExceptionGroup(
  |     ...<12 lines>...
  |     )
  | ExceptionGroup: group1 (1 sub-exception)
  +-+---------------- 1 ----------------
    | ExceptionGroup: group2 (1 sub-exception)
    +-+---------------- 1 ----------------
      | RecursionError: 4
      +------------------------------------
>>>

Note that the exceptions nested in an exception group must be instances, not types. This is because in practice the exceptions would typically be ones that have already been raised and caught by the program, along the following pattern:

>>> excs = []
... for test in tests:
...     try:
...         test.run()
...     except Exception as e:
...         excs.append(e)
...
>>> if excs:
...    raise ExceptionGroup("Test Failures", excs)
...

8.10. Enriching Exceptions with Notes

When an exception is created in order to be raised, it is usually initialized with information that describes the error that has occurred. There are cases where it is useful to add information after the exception was caught. For this purpose, exceptions have a method add_note(note) that accepts a string and adds it to the exception’s notes list. The standard traceback rendering includes all notes, in the order they were added, after the exception.

>>> try:
...     raise TypeError('bad type')
... except Exception as e:
...     e.add_note('Add some information')
...     e.add_note('Add some more information')
...     raise
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    raise TypeError('bad type')
TypeError: bad type
Add some information
Add some more information
>>>

For example, when collecting exceptions into an exception group, we may want to add context information for the individual errors. In the following each exception in the group has a note indicating when this error has occurred.

>>> def f():
...     raise OSError('operation failed')
...
>>> excs = []
>>> for i in range(3):
...     try:
...         f()
...     except Exception as e:
...         e.add_note(f'Happened in Iteration {i+1}')
...         excs.append(e)
...
>>> raise ExceptionGroup('We have some problems', excs)
  + Exception Group Traceback (most recent call last):
  |   File "<stdin>", line 1, in <module>
  |     raise ExceptionGroup('We have some problems', excs)
  | ExceptionGroup: We have some problems (3 sub-exceptions)
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "<stdin>", line 3, in <module>
    |     f()
    |     ~^^
    |   File "<stdin>", line 2, in f
    |     raise OSError('operation failed')
    | OSError: operation failed
    | Happened in Iteration 1
    +---------------- 2 ----------------
    | Traceback (most recent call last):
    |   File "<stdin>", line 3, in <module>
    |     f()
    |     ~^^
    |   File "<stdin>", line 2, in f
    |     raise OSError('operation failed')
    | OSError: operation failed
    | Happened in Iteration 2
    +---------------- 3 ----------------
    | Traceback (most recent call last):
    |   File "<stdin>", line 3, in <module>
    |     f()
    |     ~^^
    |   File "<stdin>", line 2, in f
    |     raise OSError('operation failed')
    | OSError: operation failed
    | Happened in Iteration 3
    +------------------------------------
>>>

9. 클래스

클래스는 데이터와 기능을 함께 묶는 방법을 제공합니다. 새 클래스를 만드는 것은 객체의 새 형 을 만들어서, 그 형의 새 인스턴스 를 만들 수 있도록 합니다. 각 클래스 인스턴스는 상태를 유지하기 위해 그 자신에게 첨부된 어트리뷰트를 가질 수 있습니다. 클래스 인스턴스는 상태를 바꾸기 위한 (클래스에 의해 정의된) 메서드도 가질 수 있습니다.

다른 프로그래밍 언어들과 비교할 때, 파이썬의 클래스 메커니즘은 최소한의 새로운 문법과 개념을 써서 클래스를 추가합니다. C++ 과 모듈라-3 에서 발견되는 클래스 메커니즘을 혼합합니다. 파이썬 클래스는 객체 지향형 프로그래밍의 모든 표준 기능들을 제공합니다: 클래스 상속 메커니즘은 다중 베이스 클래스를 허락하고, 자식 클래스는 베이스 클래스나 클래스들의 어떤 메서드도 재정의할 수 있으며, 메서드는 같은 이름의 베이스 클래스의 메서드를 호출할 수 있습니다. 객체들은 임의의 종류의 데이터를 양적 제한 없이 가질 수 있습니다. 모듈과 마찬가지로, 클래스는 파이썬의 동적인 본성을 함께 나눕니다: 실행 시간에 만들어지고, 만들어진 후에도 더 수정될 수 있습니다.

C++ 용어로, 보통 클래스 멤버들은 (데이터 멤버를 포함해서) public (예외는 아래 비공개 변수 를 보세요) 하고, 모든 맴버 함수들은 virtual 입니다. 모듈라-3처럼, 객체의 매소드에서 그 객체의 멤버를 참조하는 줄임 표현은 없습니다: 메서드 함수는 그 객체를 표현하는 명시적인 첫 번째 인자를 선언하는데, 함수 호출 때 묵시적으로 제공됩니다. 스몰토크처럼, 클래스 자신도 객체입니다. 이것이 임포팅과 이름 변경을 위한 개념을 제공합니다. C++ 나 모듈라-3 와는 달리, 내장형도 사용자가 확장하기 위해 베이스 클래스로 사용할 수 있습니다. 또한, C++ 처럼, 특별한 문법을 갖는 대부분의 내장 연산자들은 (산술 연산자, 서브스크립팅, 등등) 클래스 인스턴스에 대해 새로 정의될 수 있습니다.

(클래스에 대해 보편적으로 받아들여지는 용어들이 없는 상태에서, 이따금 스몰토크나 C++ 용어들을 사용할 것입니다. C++ 보다 객체 지향적 개념들이 파이썬의 것과 더 가까우므로 모듈라-3 용어를 사용할 수도 있지만, 들어본 독자들이 별로 없을 것으로 예상합니다.)

9.1. 이름과 객체에 관한 한마디

객체는 개체성(individuality)을 갖고, 여러 개의 이름이 (여러 개의 스코프에서) 같은 객체에 연결될 수 있습니다. 이것은 다른 언어들에서는 에일리어싱(aliasing) 이라고 알려져 있습니다. 보통 파이썬을 처음 볼 때 이 점을 높이 평가하지는 않고, 불변 기본형들 (숫자, 문자열, 튜플)을 다루는 동안은 안전하게 무시할 수 있습니다. 하지만, 에일리어싱는 리스트, 딕셔너리나 그 밖의 다른 가변 객체들을 수반하는 파이썬 코드의 의미에 극적인 효과를 줄 수 있습니다. 이것은 보통 프로그램에 혜택이 되는데, 에일리어스는 어떤 면에서 포인터처럼 동작하기 때문입니다. 예를 들어, 구현이 포인터만 전달하기 때문에, 객체를 전달하는 비용이 적게 듭니다; 그리고 함수가 인자로 전달된 객체를 수정하면, 호출자는 그 변경을 보게 됩니다 — 이것은 파스칼에서 사용되는 두 가지 서로 다른 인자 전달 메커니즘의 필요를 제거합니다.

9.2. 파이썬 스코프와 이름 공간

클래스를 소개하기 전에, 파이썬의 스코프 규칙에 대해 몇 가지 말할 것이 있습니다. 클래스 정의는 이름 공간으로 깔끔한 요령을 부리고, 여러분은 무엇이 일어나는지 완전히 이해하기 위해 스코프와 이름 공간이 어떻게 동작하는지 알 필요가 있습니다. 덧붙여 말하자면, 이 주제에 대한 지식은 모든 고급 파이썬 프로그래머에게 쓸모가 있습니다.

몇 가지 정의로 시작합시다.

이름 공간 은 이름에서 객체로 가는 매핑입니다. 대부분의 이름 공간은 현재 파이썬 딕셔너리로 구현되어 있지만, 보통 다른 식으로는 알아차릴 수 없고 (성능은 예외입니다), 앞으로는 바뀔 수 있습니다. 이름 공간의 예는: 내장 이름들의 집합 (abs() 와 같은 함수들과 내장 예외 이름들을 포함합니다); 모듈의 전역 이름들; 함수 호출에서의 지역 이름들. 어떤 의미에서 객체의 어트리뷰트 집합도 이름 공간을 형성합니다. 이름 공간에 대해 알아야 할 중요한 것은 서로 다른 이름 공간들의 이름 간에는 아무런 관계가 없다는 것입니다; 예를 들어, 두 개의 서로 다른 모듈들은 모두 혼동 없이 함수 maximize 를 정의할 수 있습니다 — 모듈의 사용자들은 모듈 이름을 앞에 붙여야 합니다.

그런데, 저는 어트리뷰트 라는 단어를 점 뒤에 오는 모든 이름에 사용합니다 — 예를 들어, 표현식 z.real 에서, real 는 객체 z 의 어트리뷰트입니다. 엄밀하게 말해서, 모듈에 있는 이름들에 대한 참조는 어트리뷰트 참조입니다: 표현식 modname.funcname 에서, modname 은 모듈 객체고 funcname 는 그것의 어트리뷰트입니다. 이 경우에는 우연히도 모듈의 어트리뷰트와 모듈에서 정의된 전역 이름 간에 직접적인 매핑이 생깁니다: 같은 이름 공간을 공유합니다! [1]

Attributes may be read-only or writable. In the latter case, assignment to attributes is possible. Module attributes are writable: you can write modname.the_answer = 42. Writable attributes may also be deleted with the del statement. For example, del modname.the_answer will remove the attribute the_answer from the object named by modname.

이름 공간들은 서로 다른 순간에 만들어지고 서로 다른 수명을 갖습니다. 내장 이름들을 담는 이름 공간은 파이썬 인터프리터가 시작할 때 만들어지고 영원히 지워지지 않습니다. 모듈의 전역 이름 공간은 모듈 정의를 읽는 동안 만들어집니다; 보통, 모듈 이름 공간은 인터프리터가 끝날 때까지 남습니다. 인터프리터의 최상위 호출 때문에 실행되는, 스크립트 파일이나 대화형으로 읽히는, 문장들은 __main__ 이라고 불리는 모듈 일부로 여겨져서 그 들 자신의 이름 공간을 갖습니다. (내장 이름들 또한 모듈에 속하는데; 이것을 builtins 라 부릅니다.)

함수의 지역 이름 공간은 함수가 호출될 때 만들어지고, 함수가 복귀하거나 함수 내에서 처리되지 않는 예외를 일으킬 때 삭제됩니다. (사실, 잊어버린다는 것이 실제로 일어나는 일에 대한 더 좋은 설명입니다.) 물론, 재귀적 호출은 각각 자기 자신만의 지역 이름 공간을 갖습니다.

스코프 는 이름 공간을 직접 액세스할 수 있는 파이썬 프로그램의 텍스트 적인 영역입니다. 여기에서 “직접 액세스 가능한” 이란 이름에 대한 정규화되지 않은 참조가 그 이름 공간에서 이름을 찾으려고 시도한다는 의미입니다.

스코프가 정적으로 결정됨에도 불구하고, 동적으로 사용됩니다. 실행 중 어느 시점에서건, 이름 공간을 직접 액세스 가능한, 세 개나 네 개의 중첩된 스코프가 있습니다:

가장 먼저 검색되는, 가장 내부의 스코프는 지역 이름들을 포함합니다

the scopes of any enclosing functions, which are searched starting with the nearest enclosing scope, contain non-local, but also non-global names

마지막 직전의 스코프는 현재 모듈의 전역 이름들을 포함합니다

(가장 나중에 검색되는) 가장 외부의 스코프는 내장 이름들을 포함하고 있는 이름 공간입니다.

If a name is declared global, then all references and assignments go directly to the next-to-last scope containing the module’s global names. To rebind variables found outside of the innermost scope, the nonlocal statement can be used; if not declared nonlocal, those variables are read-only (an attempt to write to such a variable will simply create a new local variable in the innermost scope, leaving the identically named outer variable unchanged).

보통, 지역 스코프는 현재 함수의 지역 이름들을 (텍스트 적으로) 참조합니다. 함수 바깥에서, 지역 스코프는 전역 스코프와 같은 이름 공간을 참조합니다: 모듈의 이름 공간. 클래스 정의들은 지역 스코프에 또 하나의 이름 공간을 배치합니다.

스코프가 텍스트 적으로 결정된다는 것을 깨닫는 것은 중요합니다: 모듈에서 정의된 함수의 전역 스코프는, 어디에서 어떤 에일리어스를 통해 그 함수가 호출되는지에 관계없이, 그 모듈의 이름 공간입니다. 반면에, 이름을 실제로 검색하는 것은 실행시간에 동적으로 수행됩니다 — 하지만, 언어 정의는 컴파일 시점의 정적인 이름 결정을 향해 진화하고 있어서, 동적인 이름 결정에 의존하지 말아야 합니다! (사실, 지역 변수들은 이미 정적으로 결정됩니다.)

파이썬의 특별한 특징은 – global이나 nonlocal 문이 없을 때 – 이름에 대입하면 항상 가장 내부의 스코프로 간다는 것입니다. 대입은 데이터를 복사하지 않습니다 – 이름을 단지 객체에 연결할 뿐입니다. 삭제도 마찬가지입니다: 문장 del x 는 지역 스코프가 참조하는 이름 공간에서 x 의 연결을 제거합니다. 사실, 새 이름을 소개하는 모든 연산은 지역 스코프를 사용합니다: 특히, import 문과 함수 정의는 모듈이나 함수 이름을 지역 스코프에 연결합니다.

global 문은 특정 변수가 전역 스코프에 있으며 그곳에 재연결되어야 함을 가리킬 때 사용될 수 있습니다; nonlocal 문은 특정 변수가 둘러싸는 스코프에 있으며 그곳에 재연결되어야 함을 가리킵니다.

9.2.1. 스코프와 이름 공간 예

이것은 어떻게 서로 다른 스코프와 이름 공간을 참조하고, global 과 nonlocal 이 변수 연결에 어떤 영향을 주는지를 보여주는 예입니다:

def scope_test():
    def do_local():
        spam = "local spam"

    def do_nonlocal():
        nonlocal spam
        spam = "nonlocal spam"

    def do_global():
        global spam
        spam = "global spam"

    spam = "test spam"
    do_local()
    print("After local assignment:", spam)
    do_nonlocal()
    print("After nonlocal assignment:", spam)
    do_global()
    print("After global assignment:", spam)

scope_test()
print("In global scope:", spam)

예제 코드의 출력은 이렇게 됩니다:

After local assignment: test spam
After nonlocal assignment: nonlocal spam
After global assignment: nonlocal spam
In global scope: global spam

어떻게 지역 대입이 (이것이 기본입니다) scope_test 의 spam 연결을 바꾸지 않는지에 유의하세요. nonlocal 대입은 scope_test 의 spam 연결을 바꾸고 global 대입은 모듈 수준의 연결을 바꿉니다.

global 대입 전에는 spam 의 연결이 없다는 것도 볼 수 있습니다.

9.3. 클래스와의 첫 만남

클래스는 약간의 새 문법과 세 개의 객체형과 몇 가지 새 개념들을 도입합니다.

9.3.1. 클래스 정의 문법

클래스 정의의 가장 간단한 형태는 이렇게 생겼습니다:

class ClassName:
    <statement-1>
    .
    .
    .
    <statement-N>

함수 정의(def 문)처럼, 클래스 정의는 어떤 효과가 생기기 위해서는 먼저 실행되어야 합니다. (상상컨대 클래스 정의를 if 문의 분기나 함수 내부에 놓을 수 있습니다)

실재적으로, 클래스 정의 내부의 문장들은 보통 함수 정의들이지만, 다른 문장들도 허락되고 때로 쓸모가 있습니다 — 나중에 이 주제로 돌아올 것입니다. 클래스 내부의 함수 정의는 보통, 메서드 호출 규약의 영향을 받은, 특별한 형태의 인자 목록을 갖습니다. — 다시, 이것은 뒤에서 설명됩니다.

클래스 정의에 진입할 때, 새 이름 공간이 만들어지고 지역 스코프로 사용됩니다 — 그래서, 모든 지역 변수들로의 대입은 이 새 이름 공간으로 갑니다. 특히, 함수 정의는 새 함수의 이름을 이곳에 연결합니다.

When a class definition is left normally (via the end), a class object is created. This is basically a wrapper around the contents of the namespace created by the class definition; we’ll learn more about class objects in the next section. The original local scope (the one in effect just before the class definition was entered) is reinstated, and the class object is bound here to the class name given in the class definition header (ClassName in the example).

9.3.2. 클래스 객체

클래스 객체는 두 종류의 연산을 지원합니다: 어트리뷰트 참조와 인스턴스 만들기.

어트리뷰트 참조 는 파이썬의 모든 어트리뷰트 참조에 사용되는 표준 문법을 사용합니다: obj.name. 올바른 어트리뷰트 이름은 클래스 객체가 만들어질 때 클래스의 이름 공간에 있던 모든 이름입니다. 그래서, 클래스 정의가 이렇게 될 때:

class MyClass:
    """A simple example class"""
    i = 12345

    def f(self):
        return 'hello world'

then MyClass.i and MyClass.f are valid attribute references, returning an integer and a function object, respectively. Class attributes can also be assigned to, so you can change the value of MyClass.i by assignment. __doc__ is also a valid attribute, returning the docstring belonging to the class: "A simple example class".

클래스 인스턴스 만들기 는 함수 표기법을 사용합니다. 클래스 객체가 클래스의 새 인스턴스를 돌려주는 매개변수 없는 함수인 체합니다. 예를 들어 (위의 클래스를 가정하면):

x = MyClass()

는 클래스의 새 인스턴스 를 만들고 이 객체를 지역 변수 x 에 대입합니다.

The instantiation operation (“calling” a class object) creates an empty object. Many classes like to create objects with instances customized to a specific initial state. Therefore a class may define a special method named __init__(), like this:

def __init__(self):
    self.data = []

When a class defines an __init__() method, class instantiation automatically invokes __init__() for the newly created class instance. So in this example, a new, initialized instance can be obtained by:

x = MyClass()

Of course, the __init__() method may have arguments for greater flexibility. In that case, arguments given to the class instantiation operator are passed on to __init__(). For example,

>>> class Complex:
...     def __init__(self, realpart, imagpart):
...         self.r = realpart
...         self.i = imagpart
...
>>> x = Complex(3.0, -4.5)
>>> x.r, x.i
(3.0, -4.5)

9.3.3. 인스턴스 객체

이제 인스턴스 객체로 무엇을 할 수 있을까? 인스턴스 객체가 이해하는 오직 한가지 연산은 어트리뷰트 참조입니다. 두 가지 종류의 올바른 어트리뷰트 이름이 있습니다: 데이터 어트리뷰트와 메서드.

data attributes correspond to “instance variables” in Smalltalk, and to “data members” in C++. Data attributes need not be declared; like local variables, they spring into existence when they are first assigned to. For example, if x is the instance of MyClass created above, the following piece of code will print the value 16, without leaving a trace:

x.counter = 1
while x.counter < 10:
    x.counter = x.counter * 2
print(x.counter)
del x.counter

The other kind of instance attribute reference is a method. A method is a function that “belongs to” an object.

인스턴스 객체의 올바른 메서드 이름은 그것의 클래스에 달려있습니다. 정의상, 함수 객체인 클래스의 모든 어트리뷰트들은 상응하는 인스턴스의 메서드들을 정의합니다. 그래서 우리의 예제에서, x.f 는 올바른 메서드 참조인데, MyClass.f 가 함수이기 때문입니다. 하지만 x.i 는 그렇지 않은데, MyClass.i 가 함수가 아니기 때문입니다. 그러나, x.f 는 MyClass.f 와 같은 것이 아닙니다 — 이것은 함수 객체가 아니라 메서드 객체 입니다.

9.3.4. 메서드 객체

보통, 메서드는 연결되자마자 호출됩니다:

x.f()

In the MyClass example, this will return the string 'hello world'. However, it is not necessary to call a method right away: x.f is a method object, and can be stored away and called at a later time. For example:

xf = x.f
while True:
    print(xf())

는 영원히 계속 hello world 를 인쇄합니다.

What exactly happens when a method is called? You may have noticed that x.f() was called without an argument above, even though the function definition for f() specified an argument. What happened to the argument? Surely Python raises an exception when a function that requires an argument is called without any — even if the argument isn’t actually used…

실제로, 여러분은 답을 짐작할 수 있습니다: 메서드의 특별함은 인스턴스 객체가 함수의 첫 번째 인자로 전달된다는 것입니다. 우리 예에서, 호출 x.f()는 정확히 MyClass.f(x) 와 동등합니다. 일반적으로, n 개의 인자들의 목록으로 메서드를 호출하는 것은, 첫 번째 인자 앞에 메서드의 인스턴스 객체를 삽입해서 만든 인자 목록으로 상응하는 함수를 호출하는 것과 동등합니다.

In general, methods work as follows. When a non-data attribute of an instance is referenced, the instance’s class is searched. If the name denotes a valid class attribute that is a function object, references to both the instance object and the function object are packed into a method object. When the method object is called with an argument list, a new argument list is constructed from the instance object and the argument list, and the function object is called with this new argument list.

9.3.5. 클래스와 인스턴스 변수

일반적으로 말해서, 인스턴스 변수는 인스턴스별 데이터를 위한 것이고 클래스 변수는 그 클래스의 모든 인스턴스에서 공유되는 어트리뷰트와 메서드를 위한 것입니다:

class Dog:

    kind = 'canine'         # class variable shared by all instances

    def __init__(self, name):
        self.name = name    # instance variable unique to each instance

>>> d = Dog('Fido')
>>> e = Dog('Buddy')
>>> d.kind                  # shared by all dogs
'canine'
>>> e.kind                  # shared by all dogs
'canine'
>>> d.name                  # unique to d
'Fido'
>>> e.name                  # unique to e
'Buddy'

이름과 객체에 관한 한마디 에서 논의했듯이, 리스트나 딕셔너리와 같은 가변 객체가 참여할 때 공유 데이터는 예상치 못한 효과를 줄 가능성이 있습니다. 예를 들어, 다음 코드에서 tricks 리스트는 클래스 변수로 사용되지 않아야 하는데, 하나의 리스트가 모든 Dog 인스턴스들에 공유되기 때문입니다.

class Dog:

    tricks = []             # mistaken use of a class variable

    def __init__(self, name):
        self.name = name

    def add_trick(self, trick):
        self.tricks.append(trick)

>>> d = Dog('Fido')
>>> e = Dog('Buddy')
>>> d.add_trick('roll over')
>>> e.add_trick('play dead')
>>> d.tricks                # unexpectedly shared by all dogs
['roll over', 'play dead']

대신, 클래스의 올바른 설계는 인스턴스 변수를 사용해야 합니다:

class Dog:

    def __init__(self, name):
        self.name = name
        self.tricks = []    # creates a new empty list for each dog

    def add_trick(self, trick):
        self.tricks.append(trick)

>>> d = Dog('Fido')
>>> e = Dog('Buddy')
>>> d.add_trick('roll over')
>>> e.add_trick('play dead')
>>> d.tricks
['roll over']
>>> e.tricks
['play dead']

9.4. 기타 주의사항들

인스턴스와 클래스 모두에서 같은 어트리뷰트 이름이 등장하면, 어트리뷰트 조회는 인스턴스를 우선합니다:

>>> class Warehouse:
...    purpose = 'storage'
...    region = 'west'
...
>>> w1 = Warehouse()
>>> print(w1.purpose, w1.region)
storage west
>>> w2 = Warehouse()
>>> w2.region = 'east'
>>> print(w2.purpose, w2.region)
storage east

데이터 어트리뷰트는 메서드 뿐만 아니라 객체의 일반적인 사용자 (“클라이언트”)에 의해서 참조될 수도 있습니다. 달리 표현하면, 클래스는 순수하게 추상적인 데이터형을 구현하는데 사용될 수 없습니다. 사실, 파이썬에서는 데이터 은닉을 강제할 방법이 없습니다 — 모두 관례에 의존합니다. (반면에, C로 작성된 파이썬 구현은 필요하다면 구현 상세를 완전히 숨기고 객체에 대한 액세스를 제어할 수 있습니다; 이것은 C로 작성된 파이썬 확장에서 사용될 수 있습니다.)

클라이언트는 데이터 어트리뷰트를 조심스럽게 사용해야 합니다 — 클라이언트는 데이터 어트리뷰트를 건드려서 메서드들에 의해 유지되는 불변성 들을 망가뜨릴 수 있습니다. 클라이언트는 이름 충돌을 피하는 한 메서드들의 유효성을 손상하지 않고도 그들 자신의 데이터 어트리뷰트를 인스턴스 객체에 추가할 수도 있음에 유의하세요 — 다시 한번, 명명 규칙은 여러 골칫거리를 피할 수 있게 합니다.

메서드 안에서 데이터 어트리뷰트들(또는 다른 메서드들!)을 참조하는 줄임 표현은 없습니다. 저는 이것이 실제로 메서드의 가독성을 높인다는 것을 알게 되었습니다: 메서드를 훑어볼 때 지역 변수와 인스턴스 변수를 혼동할 우려가 없습니다.

종종, 메서드의 첫 번째 인자는 self 라고 불립니다. 이것은 관례일 뿐입니다: 이름 self 는 파이썬에서 아무런 특별한 의미를 갖지 않습니다. 하지만, 이 규칙을 따르지 않을 때 여러분의 코드가 다른 파이썬 프로그래머들이 읽기에 불편하고, 클래스 브라우저 프로그램도 이런 규칙에 의존하도록 작성되었다고 상상할 수 있음에 유의하세요.

클래스 어트리뷰트인 모든 함수는 그 클래스의 인스턴스들을 위한 메서드를 정의합니다. 함수 정의가 클래스 정의에 텍스트 적으로 둘러싸일 필요는 없습니다: 함수 객체를 클래스의 지역 변수로 대입하는 것 역시 가능합니다. 예를 들어:

# Function defined outside the class
def f1(self, x, y):
    return min(x, x+y)

class C:
    f = f1

    def g(self):
        return 'hello world'

    h = g

Now f, g and h are all attributes of class C that refer to function objects, and consequently they are all methods of instances of C — h being exactly equivalent to g. Note that this practice usually only serves to confuse the reader of a program.

메서드는 self 인자의 메서드 어트리뷰트를 사용해서 다른 메서드를 호출할 수 있습니다:

class Bag:
    def __init__(self):
        self.data = []

    def add(self, x):
        self.data.append(x)

    def addtwice(self, x):
        self.add(x)
        self.add(x)

메서드는 일반 함수들과 마찬가지로 전역 이름을 참조할 수 있습니다. 메서드에 결합한 전역 스코프는 그것의 정의를 포함하는 모듈입니다. (클래스는 결코 전역 스코프로 사용되지 않습니다.) 메서드에서 전역 데이터를 사용할 좋은 이유를 거의 만나지 못하지만, 전역 스코프를 정당하게 사용하는 여러 가지 경우가 있습니다: 한가지는, 전역 스코프에 정의된 함수와 메서드 뿐만 아니라, 그곳에 임포트된 함수와 모듈도 메서드가 사용할 수 있다는 것입니다. 보통, 메서드를 포함하는 클래스 자신은 이 전역 스코프에 정의되고, 다음 섹션에서 메서드가 자신의 클래스를 참조하길 원하는 몇 가지 좋은 이유를 보게 될 것입니다.

각 값은 객체고, 그러므로 클래스 (형 이라고도 불린다) 를 갖습니다. 이것은 object.__class__ 에 저장되어 있습니다.

9.5. 상속

물론, 상속을 지원하지 않는다면 언어 기능은 “클래스”라는 이름을 붙일만한 가치가 없을 것입니다. 파생 클래스 정의의 문법은 이렇게 생겼습니다:

class DerivedClassName(BaseClassName):
    <statement-1>
    .
    .
    .
    <statement-N>

The name BaseClassName must be defined in a namespace accessible from the scope containing the derived class definition. In place of a base class name, other arbitrary expressions are also allowed. This can be useful, for example, when the base class is defined in another module:

class DerivedClassName(modname.BaseClassName):

파생 클래스 정의의 실행은 베이스 클래스와 같은 방식으로 진행됩니다. 클래스 객체가 만들어질 때, 베이스 클래스가 기억됩니다. 이것은 어트리뷰트 참조를 결정할 때 사용됩니다: 요청된 어트리뷰트가 클래스에서 발견되지 않으면 베이스 클래스로 검색을 확장합니다. 베이스 클래스 또한 다른 클래스로부터 파생되었다면 이 규칙은 재귀적으로 적용됩니다.

파생 클래스의 인스턴스 만들기에 특별한 것은 없습니다: DerivedClassName() 는 그 클래스의 새 인스턴스를 만듭니다. 메서드 참조는 다음과 같이 결정됩니다: 대응하는 클래스 어트리뷰트가 검색되는데, 필요하면 베이스 클래스의 연쇄를 타고 내려갑니다. 이것이 함수 객체를 준다면 메서드 참조는 올바릅니다.

파생 클래스는 베이스 클래스의 메서드들을 재정의할 수 있습니다. 메서드가 같은 객체의 다른 메서드를 호출할 때 특별한 권한 같은 것은 없으므로, 베이스 클래스에 정의된 다른 메서드를 호출하는 베이스 클래스의 메서드는 재정의된 파생 클래스의 메서드를 호출하게 됩니다. (C++ 프로그래머를 위한 표현으로: 파이썬의 모든 메서드는 실질적으로 virtual 입니다.)

파생 클래스에서 재정의된 메서드가, 같은 이름의 베이스 클래스 메서드를 단순히 갈아치우기보다 사실은 확장하고 싶을 수 있습니다. 베이스 클래스의 메서드를 직접 호출하는 간단한 방법이 있습니다: 단지 BaseClassName.methodname(self, arguments) 를 호출하면 됩니다. 이것은 때로 클라이언트에게도 쓸모가 있습니다. (이것은 베이스 클래스가 전역 스코프에서 BaseClassName 으로 액세스 될 수 있을 때만 동작함에 주의하세요.)

파이썬에는 상속과 함께 사용할 수 있는 두 개의 내장 함수가 있습니다:

인스턴스의 형을 검사하려면 isinstance() 를 사용합니다: isinstance(obj, int) 는 obj.__class__ 가 int 거나 int 에서 파생된 클래스인 경우만 True 가 됩니다.

클래스 상속을 검사하려면 issubclass() 를 사용합니다: issubclass(bool, int) 는 True 인데, bool 이 int 의 서브 클래스이기 때문입니다. 하지만, issubclass(float, int) 는 False 인데, float 는 int 의 서브 클래스가 아니기 때문입니다.

9.5.1. 다중 상속

파이썬은 다중 상속의 형태도 지원합니다. 여러 개의 베이스 클래스를 갖는 클래스 정의는 이런 식입니다:

class DerivedClassName(Base1, Base2, Base3):
    <statement-1>
    .
    .
    .
    <statement-N>

For most purposes, in the simplest cases, you can think of the search for attributes inherited from a parent class as depth-first, left-to-right, not searching twice in the same class where there is an overlap in the hierarchy. Thus, if an attribute is not found in DerivedClassName, it is searched for in Base1, then (recursively) in the base classes of Base1, and if it was not found there, it was searched for in Base2, and so on.

사실, 이것보다는 약간 더 복잡합니다; 메서드 결정 순서는 super() 로의 협력적인 호출을 지원하기 위해 동적으로 변경됩니다. 이 접근법은 몇몇 다른 다중 상속 언어들에서 call-next-method 라고 알려져 있고, 단일 상속 언어들에서 발견되는 super 호출보다 더 강력합니다.

Dynamic ordering is necessary because all cases of multiple inheritance exhibit one or more diamond relationships (where at least one of the parent classes can be accessed through multiple paths from the bottommost class). For example, all classes inherit from object, so any case of multiple inheritance provides more than one path to reach object. To keep the base classes from being accessed more than once, the dynamic algorithm linearizes the search order in a way that preserves the left-to-right ordering specified in each class, that calls each parent only once, and that is monotonic (meaning that a class can be subclassed without affecting the precedence order of its parents). Taken together, these properties make it possible to design reliable and extensible classes with multiple inheritance. For more detail, see The Python 2.3 Method Resolution Order.

9.6. 비공개 변수

객체 내부에서만 액세스할 수 있는 “비공개” 인스턴스 변수는 파이썬에 존재하지 않습니다. 하지만, 대부분의 파이썬 코드에서 따르고 있는 규약이 있습니다: 밑줄로 시작하는 이름은 (예를 들어, _spam) API의 공개적이지 않은 부분으로 취급되어야 합니다 (그것이 함수, 메서드, 데이터 멤버중 무엇이건 간에). 구현 상세이고 통보 없이 변경되는 대상으로 취급되어야 합니다.

클래스-비공개 멤버들의 올바른 사례가 있으므로 (즉 서브 클래스에서 정의된 이름들과의 충돌을 피하고자), 이름 뒤섞기 (name mangling) 라고 불리는 메커니즘에 대한 제한된 지원이 있습니다. __spam 형태의 (최소 두 개의 밑줄로 시작하고, 최대 한 개의 밑줄로 끝납니다) 모든 식별자는 _classname__spam 로 텍스트 적으로 치환되는데, classname 은 현재 클래스 이름에서 앞에 오는 밑줄을 제거한 것입니다. 이 뒤섞기는 클래스 정의에 등장하는 이상, 식별자의 문법적 위치와 무관하게 수행됩니다.

더 보기

The private name mangling specifications for details and special cases.

이름 뒤섞기는 클래스 내부의 메서드 호출을 방해하지 않고 서브 클래스들이 메서드를 재정의할 수 있도록 하는 데 도움을 줍니다. 예를 들어:

class Mapping:
    def __init__(self, iterable):
        self.items_list = []
        self.__update(iterable)

    def update(self, iterable):
        for item in iterable:
            self.items_list.append(item)

    __update = update   # private copy of original update() method

class MappingSubclass(Mapping):

    def update(self, keys, values):
        # provides new signature for update()
        # but does not break __init__()
        for item in zip(keys, values):
            self.items_list.append(item)

위의 예는 MappingSubclass가 __update 식별자를 도입하더라도 작동합니다. Mapping 클래스에서는 _Mapping__update로 MappingSubclass 클래스에서는 _MappingSubclass__update로 각각 대체 되기 때문입니다.

뒤섞기 규칙은 대체로 사고를 피하고자 설계되었다는 것에 주의하세요; 여전히 비공개로 취급되는 변수들을 액세스하거나 수정할 수 있습니다. 이것은 디버거와 같은 특별한 상황에서 쓸모 있기조차 합니다.

exec() 나 eval() 로 전달된 코드는 호출하는 클래스의 클래스 이름을 현재 클래스로 여기지 않는다는 것에 주의하세요; 이것은 global 문의 효과와 유사한데, 효과가 함께 바이트-컴파일된 코드로 제한됩니다. 같은 제약이 __dict__ 를 직접 참조할 때뿐만 아니라, getattr(), setattr(), delattr() 에도 적용됩니다.

9.7. 잡동사니

Sometimes it is useful to have a data type similar to the Pascal “record” or C “struct”, bundling together a few named data items. The idiomatic approach is to use dataclasses for this purpose:

from dataclasses import dataclass

@dataclass
class Employee:
    name: str
    dept: str
    salary: int

>>> john = Employee('john', 'computer lab', 1000)
>>> john.dept
'computer lab'
>>> john.salary
1000

A piece of Python code that expects a particular abstract data type can often be passed a class that emulates the methods of that data type instead. For instance, if you have a function that formats some data from a file object, you can define a class with methods read() and readline() that get the data from a string buffer instead, and pass it as an argument.

Instance method objects have attributes, too: m.__self__ is the instance object with the method m(), and m.__func__ is the function object corresponding to the method.

9.8. 이터레이터

지금쯤 아마도 여러분은 대부분의 컨테이너 객체들을 for 문으로 루핑할 수 있음을 눈치챘을 것입니다:

for element in [1, 2, 3]:
    print(element)
for element in (1, 2, 3):
    print(element)
for key in {'one':1, 'two':2}:
    print(key)
for char in "123":
    print(char)
for line in open("myfile.txt"):
    print(line, end='')

이런 스타일의 액세스는 명료하고, 간결하고, 편리합니다. 이터레이터를 사용하면 파이썬이 보편화하고 통합됩니다. 무대 뒤에서, for 문은 컨테이너 객체에 대해 iter() 를 호출합니다. 이 함수는 메서드 __next__() 를 정의하는 이터레이터 객체를 돌려주는데, 이 메서드는 컨테이너의 요소들을 한 번에 하나씩 액세스합니다. 남은 요소가 없으면, __next__() 는 StopIteration 예외를 일으켜서 for 루프에 종료를 알립니다. next() 내장 함수를 사용해서 __next__() 메서드를 호출할 수 있습니다; 이 예는 이 모든 것들이 어떻게 동작하는지 보여줍니다:

>>> s = 'abc'
>>> it = iter(s)
>>> it
<str_iterator object at 0x10c90e650>
>>> next(it)
'a'
>>> next(it)
'b'
>>> next(it)
'c'
>>> next(it)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    next(it)
StopIteration

Having seen the mechanics behind the iterator protocol, it is easy to add iterator behavior to your classes. Define an __iter__() method which returns an object with a __next__() method. If the class defines __next__(), then __iter__() can just return self:

class Reverse:
    """Iterator for looping over a sequence backwards."""
    def __init__(self, data):
        self.data = data
        self.index = len(data)

    def __iter__(self):
        return self

    def __next__(self):
        if self.index == 0:
            raise StopIteration
        self.index = self.index - 1
        return self.data[self.index]

>>> rev = Reverse('spam')
>>> iter(rev)
<__main__.Reverse object at 0x00A1DB50>
>>> for char in rev:
...     print(char)
...
m
a
p
s

9.9. 제너레이터

제너레이터 는 이터레이터를 만드는 간단하고 강력한 도구입니다. 일반적인 함수처럼 작성되지만 값을 돌려주고 싶을 때마다 yield 문을 사용합니다. 제너레이터에 next() 가 호출될 때마다, 제너레이터는 떠난 곳에서 실행을 재개합니다 (모든 데이터 값들과 어떤 문장이 마지막으로 실행되었는지 기억합니다). 예는 제너레이터를 사소할 정도로 쉽게 만들 수 있음을 보여줍니다:

def reverse(data):
    for index in range(len(data)-1, -1, -1):
        yield data[index]

>>> for char in reverse('golf'):
...     print(char)
...
f
l
o
g

Anything that can be done with generators can also be done with class-based iterators as described in the previous section. What makes generators so compact is that the __iter__() and __next__() methods are created automatically.

또 하나의 주요 기능은 지역 변수들과 실행 상태가 호출 간에 자동으로 보관된다는 것입니다. 이것은 self.index 나 self.data 와 같은 인스턴스 변수를 사용하는 접근법에 비교해 함수를 쓰기 쉽고 명료하게 만듭니다.

자동 메서드 생성과 프로그램 상태의 저장에 더해, 제너레이터가 종료할 때 자동으로 StopIteration 을 일으킵니다. 조합하면, 이 기능들이 일반 함수를 작성하는 것만큼 이터레이터를 만들기 쉽게 만듭니다.

9.10. 제너레이터 표현식

간단한 제너레이터는 리스트 컴프리헨션과 비슷하지만, 대괄호 대신 괄호를 사용하는 문법을 사용한 표현식으로 간결하게 코딩할 수 있습니다. 이 표현식들은 둘러싸는 함수가 제너레이터를 즉시 사용하는 상황을 위해 설계되었습니다. 제너레이터 표현식은 완전한 제너레이터 정의보다 간결하지만, 융통성은 떨어지고, 비슷한 리스트 컴프리헨션보다 메모리를 덜 쓰는 경향이 있습니다.

예:

>>> sum(i*i for i in range(10))                 # sum of squares
285

>>> xvec = [10, 20, 30]
>>> yvec = [7, 5, 3]
>>> sum(x*y for x,y in zip(xvec, yvec))         # dot product
260

>>> unique_words = set(word for line in page  for word in line.split())

>>> valedictorian = max((student.gpa, student.name) for student in graduates)

>>> data = 'golf'
>>> list(data[i] for i in range(len(data)-1, -1, -1))
['f', 'l', 'o', 'g']

각주

[1]

Except for one thing. Module objects have a secret read-only attribute called __dict__ which returns the dictionary used to implement the module’s namespace; the name __dict__ is an attribute but not a global name. Obviously, using this violates the abstraction of namespace implementation, and should be restricted to things like post-mortem debuggers.

10. 표준 라이브러리 둘러보기

10.1. 운영 체제 인터페이스

os 모듈은 운영 체제와 상호 작용하기 위한 수십 가지 함수들을 제공합니다:

>>> import os
>>> os.getcwd()      # Return the current working directory
'C:\\Python314'
>>> os.chdir('/server/accesslogs')   # Change current working directory
>>> os.system('mkdir today')   # Run the command mkdir in the system shell
0

from os import * 대신에 import os 스타일을 사용해야 합니다. 그래야 os.open() 이 내장 open() 을 가리는 것을 피할 수 있는데, 두 함수는 아주 다르게 동작합니다.

os 와 같은 큰 모듈과 작업할 때, 내장 dir() 과 help() 함수는 대화형 도우미로 쓸모가 있습니다.

>>> import os
>>> dir(os)
<returns a list of all module functions>
>>> help(os)
<returns an extensive manual page created from the module's docstrings>

일상적인 파일과 디렉터리 관리 작업을 위해, shutil 모듈은 사용하기 쉬운 더 고수준의 인터페이스를 제공합니다:

>>> import shutil
>>> shutil.copyfile('data.db', 'archive.db')
'archive.db'
>>> shutil.move('/build/executables', 'installdir')
'installdir'

10.2. 파일 와일드카드

glob 모듈은 디렉터리 와일드카드 검색으로 파일 목록을 만드는 함수를 제공합니다:

>>> import glob
>>> glob.glob('*.py')
['primes.py', 'random.py', 'quote.py']

10.3. 명령행 인자

Common utility scripts often need to process command line arguments. These arguments are stored in the sys module’s argv attribute as a list. For instance, let’s take the following demo.py file:

# File demo.py
import sys
print(sys.argv)

Here is the output from running python demo.py one two three at the command line:

['demo.py', 'one', 'two', 'three']

argparse 모듈은 명령 줄 인자를 처리하는 더 정교한 메커니즘을 제공합니다. 다음 스크립트는 하나 이상의 파일명과 선택적으로 표시할 줄 수를 추출합니다:

import argparse

parser = argparse.ArgumentParser(
    prog='top',
    description='Show top lines from each file')
parser.add_argument('filenames', nargs='+')
parser.add_argument('-l', '--lines', type=int, default=10)
args = parser.parse_args()
print(args)

python top.py --lines=5 alpha.txt beta.txt를 사용하여 명령 줄에서 실행할 때, 스크립트는 args.lines를 5로, args.filenames를 ['alpha.txt', 'beta.txt']로 설정합니다.

10.4. 에러 출력 리디렉션과 프로그램 종료

sys 모듈은 stdin, stdout, stderr 어트리뷰트도 갖고 있습니다. 가장 마지막 것은 stdout 이 리디렉트 되었을 때도 볼 수 있는 경고와 에러 메시지들을 출력하는데 쓸모가 있습니다:

>>> sys.stderr.write('Warning, log file not found starting a new one\n')
Warning, log file not found starting a new one

스크립트를 종료하는 가장 직접적인 방법은 sys.exit() 를 쓰는 것입니다.

10.5. 문자열 패턴 매칭

re 모듈은 고급 문자열 처리를 위한 정규식 도구들을 제공합니다. 복잡한 매칭과 조작을 위해, 정규식은 간결하고 최적화된 솔루션을 제공합니다:

>>> import re
>>> re.findall(r'\bf[a-z]*', 'which foot or hand fell fastest')
['foot', 'fell', 'fastest']
>>> re.sub(r'(\b[a-z]+) \1', r'\1', 'cat in the the hat')
'cat in the hat'

단지 간단한 기능만 필요한 경우에는, 문자열 메서드들이 선호되는데 읽기 쉽고 디버깅이 쉽기 때문입니다:

>>> 'tea for too'.replace('too', 'two')
'tea for two'

10.6. 수학

The math module gives access to the underlying C library functions for floating-point math:

>>> import math
>>> math.cos(math.pi / 4)
0.70710678118654757
>>> math.log(1024, 2)
10.0

random 모듈은 무작위 선택을 할 수 있는 도구들을 제공합니다:

>>> import random
>>> random.choice(['apple', 'pear', 'banana'])
'apple'
>>> random.sample(range(100), 10)   # sampling without replacement
[30, 83, 16, 4, 8, 81, 41, 50, 18, 33]
>>> random.random()    # random float from the interval [0.0, 1.0)
0.17970987693706186
>>> random.randrange(6)    # random integer chosen from range(6)
4

statistics 모듈은 수치 데이터의 기본적인 통계적 특성들을 (평균, 중간값, 분산, 등등) 계산합니다.

>>> import statistics
>>> data = [2.75, 1.75, 1.25, 0.25, 0.5, 1.25, 3.5]
>>> statistics.mean(data)
1.6071428571428572
>>> statistics.median(data)
1.25
>>> statistics.variance(data)
1.3720238095238095

SciPy 프로젝트 <https://scipy.org> 는 다른 수치 계산용 모듈들을 많이 갖고 있습니다.

10.7. 인터넷 액세스

인터넷을 액세스하고 인터넷 프로토콜들을 처리하는 많은 모듈이 있습니다. 가장 간단한 두 개는 URL에서 데이터를 읽어오는 urllib.request 와 메일을 보내는 smtplib 입니다:

>>> from urllib.request import urlopen
>>> with urlopen('http://worldtimeapi.org/api/timezone/etc/UTC.txt') as response:
...     for line in response:
...         line = line.decode()             # Convert bytes to a str
...         if line.startswith('datetime'):
...             print(line.rstrip())         # Remove trailing newline
...
datetime: 2022-01-01T01:36:47.689215+00:00

>>> import smtplib
>>> server = smtplib.SMTP('localhost')
>>> server.sendmail('soothsayer@example.org', 'jcaesar@example.org',
... """To: jcaesar@example.org
... From: soothsayer@example.org
...
... Beware the Ides of March.
... """)
>>> server.quit()

(두 번째 예는 localhost 에서 메일 서버가 실행되고 있어야 한다는 것에 주의하세요.)

10.8. 날짜와 시간

datetime 모듈은 날짜와 시간을 조작하는 클래스들을 제공하는데, 간단한 방법과 복잡한 방법 모두 제공합니다. 날짜와 시간 산술이 지원되지만, 구현의 초점은 출력 포매팅과 조작을 위해 효율적으로 멤버를 추출하는 데에 맞춰져 있습니다. 모듈은 시간대를 고려하는 객체들도 지원합니다.

>>> # dates are easily constructed and formatted
>>> from datetime import date
>>> now = date.today()
>>> now
datetime.date(2003, 12, 2)
>>> now.strftime("%m-%d-%y. %d %b %Y is a %A on the %d day of %B.")
'12-02-03. 02 Dec 2003 is a Tuesday on the 02 day of December.'

>>> # dates support calendar arithmetic
>>> birthday = date(1964, 7, 31)
>>> age = now - birthday
>>> age.days
14368

10.9. 데이터 압축

일반적인 데이터 보관 및 압축 형식들을 다음과 같은 모듈들이 직접 지원합니다: zlib, gzip, bz2, lzma, zipfile, tarfile.

>>> import zlib
>>> s = b'witch which has which witches wrist watch'
>>> len(s)
41
>>> t = zlib.compress(s)
>>> len(t)
37
>>> zlib.decompress(t)
b'witch which has which witches wrist watch'
>>> zlib.crc32(s)
226805979

10.10. 성능 측정

일부 파이썬 사용자들은 같은 문제에 대한 다른 접근법들의 상대적인 성능을 파악하는데 깊은 관심을 두고 있습니다. 파이썬은 이런 질문들에 즉시 답을 주는 측정 도구를 제공합니다.

예를 들어, 인자들을 맞교환하는 전통적인 방식 대신에, 튜플 패킹과 언 패킹을 사용하고자 하는 유혹을 느낄 수 있습니다. timeit 모듈은 적당한 성능 이점을 신속하게 보여줍니다:

>>> from timeit import Timer
>>> Timer('t=a; a=b; b=t', 'a=1; b=2').timeit()
0.57535828626024577
>>> Timer('a,b = b,a', 'a=1; b=2').timeit()
0.54962537085770791

timeit 의 정밀도와는 대조적으로, profile 과 pstats 모듈은 큰 블록의 코드에서 시간 임계 섹션을 식별하기 위한 도구들을 제공합니다.

10.11. 품질 관리

고품질의 소프트웨어를 개발하는 한 가지 접근법은 개발되는 각 함수에 대한 테스트를 작성하고, 그것들을 개발 프로세스 중에 자주 실행하는 것입니다.

doctest 모듈은 모듈을 훑어보고 프로그램의 독스트링들에 내장된 테스트들을 검사하는 도구를 제공합니다. 테스트 만들기는 평범한 호출을 그 결과와 함께 독스트링으로 복사해서 붙여넣기를 하는 수준으로 간단해집니다. 사용자에게 예제를 함께 제공해서 설명서를 개선하고, doctest 모듈이 설명서에서 코드가 여전히 사실인지 확인하도록 합니다.

def average(values):
    """Computes the arithmetic mean of a list of numbers.

    >>> print(average([20, 30, 70]))
    40.0
    """
    return sum(values) / len(values)

import doctest
doctest.testmod()   # automatically validate the embedded tests

unittest 모듈은 doctest 모듈만큼 쉬운 것은 아니지만, 더욱 포괄적인 테스트 집합을 별도의 파일로 관리할 수 있게 합니다:

import unittest

class TestStatisticalFunctions(unittest.TestCase):

    def test_average(self):
        self.assertEqual(average([20, 30, 70]), 40.0)
        self.assertEqual(round(average([1, 5, 7]), 1), 4.3)
        with self.assertRaises(ZeroDivisionError):
            average([])
        with self.assertRaises(TypeError):
            average(20, 30, 70)

unittest.main()  # Calling from the command line invokes all tests

10.12. 배터리가 포함됩니다

파이썬은 “배터리가 포함됩니다” 철학을 갖고 있습니다. 이는 더 큰 패키지의 정교하고 강력한 기능을 통해 가장 잘 나타납니다. 예를 들어:

The xmlrpc.client and xmlrpc.server modules make implementing remote procedure calls into an almost trivial task. Despite the modules’ names, no direct knowledge or handling of XML is needed.

email 패키지는 MIME 및 기타 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 기반 메시지 문서를 포함하는 전자 메일 메시지를 관리하기 위한 라이브러리입니다. 실제로 메시지를 보내고 받는 smtplib 와 poplib 와는 달리, email 패키지는 복잡한 메시지 구조 (첨부 파일 포함) 를 작성하거나 해독하고 인터넷 인코딩과 헤더 프로토콜을 구현하기 위한 완벽한 도구 상자를 가지고 있습니다.

json 패키지는 널리 사용되는 데이터 교환 형식을 파싱하기위한 강력한 지원을 제공합니다. csv 모듈은 데이터베이스와 스프레드시트에서 일반적으로 지원되는 쉼표로 구분된 값 형식으로 파일을 직접 읽고 쓸 수 있도록 지원합니다. XML 처리는 xml.etree.ElementTree, xml.dom 및 xml.sax 패키지에 의해 지원됩니다. 이러한 모듈과 패키지를 함께 사용하면 파이썬 응용 프로그램과 다른 도구 간의 데이터 교환이 크게 단순해집니다.

sqlite3 모듈은 SQLite 데이터베이스 라이브러리의 래퍼인데, 약간 비표준 SQL 구문을 사용하여 업데이트되고 액세스 될 수 있는 퍼시스턴트 데이터베이스를 제공합니다.

국제화는 gettext, locale, 그리고 codecs 패키지를 포함한 많은 모듈에 의해 지원됩니다.

11. 표준 라이브러리 둘러보기 — 2부

이 두 번째 둘러보기는 전문 프로그래밍 요구 사항을 지원하는 고급 모듈을 다루고 있습니다. 이러한 모듈은 작은 스크립트에서는 거의 사용되지 않습니다.

11.1. 출력 포매팅

reprlib 모듈은 크거나 깊게 중첩된 컨테이너의 축약 된 디스플레이를 위해 커스터마이즈된 repr() 의 버전을 제공합니다:

>>> import reprlib
>>> reprlib.repr(set('supercalifragilisticexpialidocious'))
"{'a', 'c', 'd', 'e', 'f', 'g', ...}"

pprint 모듈은 인터프리터가 읽을 수 있는 방식으로 내장 객체나 사용자 정의 객체를 인쇄하는 것을 보다 정교하게 제어할 수 있게 합니다. 결과가 한 줄보다 길면 “예쁜 프린터”가 줄 바꿈과 들여쓰기를 추가하여 데이터 구조를 보다 명확하게 나타냅니다:

>>> import pprint
>>> t = [[[['black', 'cyan'], 'white', ['green', 'red']], [['magenta',
...     'yellow'], 'blue']]]
...
>>> pprint.pprint(t, width=30)
[[[['black', 'cyan'],
   'white',
   ['green', 'red']],
  [['magenta', 'yellow'],
   'blue']]]

textwrap 모듈은 텍스트의 문단을 주어진 화면 너비에 맞게 포맷합니다:

>>> import textwrap
>>> doc = """The wrap() method is just like fill() except that it returns
... a list of strings instead of one big string with newlines to separate
... the wrapped lines."""
...
>>> print(textwrap.fill(doc, width=40))
The wrap() method is just like fill()
except that it returns a list of strings
instead of one big string with newlines
to separate the wrapped lines.

locale 모듈은 문화권 특정 데이터 포맷의 데이터베이스에 액세스합니다. locale의 format 함수의 grouping 어트리뷰트는 그룹 구분 기호로 숫자를 포매팅하는 직접적인 방법을 제공합니다:

>>> import locale
>>> locale.setlocale(locale.LC_ALL, 'English_United States.1252')
'English_United States.1252'
>>> conv = locale.localeconv()          # get a mapping of conventions
>>> x = 1234567.8
>>> locale.format_string("%d", x, grouping=True)
'1,234,567'
>>> locale.format_string("%s%.*f", (conv['currency_symbol'],
...                      conv['frac_digits'], x), grouping=True)
'$1,234,567.80'

11.2. 템플릿

string 모듈은 다재다능한 Template 클래스를 포함하고 있는데, 최종 사용자가 편집하기에 적절한 단순한 문법을 갖고 있습니다. 따라서 사용자는 응용 프로그램을 변경하지 않고도 응용 프로그램을 커스터마이즈할 수 있습니다.

형식은 $ 와 유효한 파이썬 식별자 (영숫자와 밑줄)로 만들어진 자리표시자 이름을 사용합니다. 중괄호를 사용하여 자리표시자를 둘러싸면 공백없이 영숫자가 뒤따르도록 할 수 있습니다. $$ 을 쓰면 하나의 이스케이프 된 $ 를 만듭니다:

>>> from string import Template
>>> t = Template('${village}folk send $$10 to $cause.')
>>> t.substitute(village='Nottingham', cause='the ditch fund')
'Nottinghamfolk send $10 to the ditch fund.'

substitute() 메서드는 자리표시자가 딕셔너리나 키워드 인자로 제공되지 않을 때 KeyError 를 일으킵니다. 메일 병합 스타일 응용 프로그램의 경우 사용자가 제공한 데이터가 불완전할 수 있으며 safe_substitute() 메서드가 더 적절할 수 있습니다. 데이터가 누락 된 경우 자리표시자를 변경하지 않습니다:

>>> t = Template('Return the $item to $owner.')
>>> d = dict(item='unladen swallow')
>>> t.substitute(d)
Traceback (most recent call last):
  ...
KeyError: 'owner'
>>> t.safe_substitute(d)
'Return the unladen swallow to $owner.'

Template 서브 클래스는 사용자 정의 구분자를 지정할 수 있습니다. 예를 들어 사진 브라우저를 위한 일괄 이름 바꾸기 유틸리티는 현재 날짜, 이미지 시퀀스 번호 또는 파일 형식과 같은 자리표시자에 백분율 기호를 사용하도록 선택할 수 있습니다:

>>> import time, os.path
>>> photofiles = ['img_1074.jpg', 'img_1076.jpg', 'img_1077.jpg']
>>> class BatchRename(Template):
...     delimiter = '%'
...
>>> fmt = input('Enter rename style (%d-date %n-seqnum %f-format):  ')
Enter rename style (%d-date %n-seqnum %f-format):  Ashley_%n%f

>>> t = BatchRename(fmt)
>>> date = time.strftime('%d%b%y')
>>> for i, filename in enumerate(photofiles):
...     base, ext = os.path.splitext(filename)
...     newname = t.substitute(d=date, n=i, f=ext)
...     print('{0} --> {1}'.format(filename, newname))

img_1074.jpg --> Ashley_0.jpg
img_1076.jpg --> Ashley_1.jpg
img_1077.jpg --> Ashley_2.jpg

템플릿의 또 다른 응용은 다중 출력 형식의 세부 사항에서 프로그램 논리를 분리하는 것입니다. 이렇게 하면 XML 파일, 일반 텍스트 보고서 및 HTML 웹 보고서에 대한 커스텀 템플릿을 치환할 수 있습니다.

11.3. 바이너리 데이터 레코드 배치 작업

struct 모듈은 가변 길이 바이너리 레코드 형식으로 작업하기 위한 pack() 과 unpack() 함수를 제공합니다. 다음 예제는 zipfile 모듈을 사용하지 않고 ZIP 파일의 헤더 정보를 루핑하는 법을 보여줍니다. 팩 코드 "H" 와 "I" 는 각각 2바이트와 4바이트의 부호 없는 숫자를 나타냅니다. "<" 는 표준 크기이면서 리틀 엔디안 바이트 순서를 가짐을 나타냅니다:

import struct

with open('myfile.zip', 'rb') as f:
    data = f.read()

start = 0
for i in range(3):                      # show the first 3 file headers
    start += 14
    fields = struct.unpack('<IIIHH', data[start:start+16])
    crc32, comp_size, uncomp_size, filenamesize, extra_size = fields

    start += 16
    filename = data[start:start+filenamesize]
    start += filenamesize
    extra = data[start:start+extra_size]
    print(filename, hex(crc32), comp_size, uncomp_size)

    start += extra_size + comp_size     # skip to the next header

11.4. 다중 스레딩

스레딩은 차례로 종속되지 않는 작업을 분리하는 기술입니다. 스레드는 다른 작업이 백그라운드에서 실행되는 동안 사용자 입력을 받는 응용 프로그램의 응답을 향상하는 데 사용할 수 있습니다. 관련된 사용 사례는 다른 스레드의 계산과 병렬로 I/O를 실행하는 경우입니다.

다음 코드는 메인 프로그램이 계속 실행되는 동안 고수준 threading 모듈이 백그라운드에서 작업을 어떻게 수행할 수 있는지 보여줍니다:

import threading, zipfile

class AsyncZip(threading.Thread):
    def __init__(self, infile, outfile):
        threading.Thread.__init__(self)
        self.infile = infile
        self.outfile = outfile

    def run(self):
        f = zipfile.ZipFile(self.outfile, 'w', zipfile.ZIP_DEFLATED)
        f.write(self.infile)
        f.close()
        print('Finished background zip of:', self.infile)

background = AsyncZip('mydata.txt', 'myarchive.zip')
background.start()
print('The main program continues to run in foreground.')

background.join()    # Wait for the background task to finish
print('Main program waited until background was done.')

다중 스레드 응용 프로그램의 가장 큰 문제점은 데이터 또는 다른 자원을 공유하는 스레드를 조정하는 것입니다. 이를 위해 threading 모듈은 록, 이벤트, 조건 변수 및 세마포어를 비롯한 많은 수의 동기화 기본 요소를 제공합니다.

이러한 도구는 강력하지만, 사소한 설계 오류로 인해 재현하기 어려운 문제가 발생할 수 있습니다. 따라서, 작업 조정에 대한 선호되는 접근 방식은 자원에 대한 모든 액세스를 단일 스레드에 집중시킨 다음 queue 모듈을 사용하여 해당 스레드에 다른 스레드의 요청을 제공하는 것입니다. 스레드 간 통신 및 조정을 위한 Queue 객체를 사용하는 응용 프로그램은 설계하기 쉽고, 읽기 쉽고, 신뢰성이 높습니다.

11.5. 로깅

logging 모듈은 완전한 기능을 갖춘 유연한 로깅 시스템을 제공합니다. 가장 단순한 경우, 로그 메시지는 파일이나 sys.stderr 로 보내집니다:

import logging
logging.debug('Debugging information')
logging.info('Informational message')
logging.warning('Warning:config file %s not found', 'server.conf')
logging.error('Error occurred')
logging.critical('Critical error -- shutting down')

그러면 다음과 같은 결과가 출력됩니다:

WARNING:root:Warning:config file server.conf not found
ERROR:root:Error occurred
CRITICAL:root:Critical error -- shutting down

기본적으로 정보 및 디버깅 메시지는 표시되지 않고 출력은 표준 에러로 보내집니다. 다른 출력 옵션에는 전자 메일, 데이터 그램, 소켓 또는 HTTP 서버를 통한 메시지 라우팅이 포함됩니다. 새로운 필터는 메시지 우선순위에 따라 다른 라우팅을 선택할 수 있습니다: DEBUG, INFO, WARNING, ERROR , 그리고 CRITICAL.

로깅 시스템은 파이썬에서 직접 구성하거나, 응용 프로그램을 변경하지 않고 사용자 정의 로깅을 위해 사용자가 편집할 수 있는 설정 파일에서 로드 할 수 있습니다.

11.6. 약한 참조

파이썬은 자동 메모리 관리 (대부분 객체에 대한 참조 횟수 추적 및 순환을 제거하기 위한 가비지 수거)를 수행합니다. 메모리는 마지막 참조가 제거된 직후에 해제됩니다.

이 접근법은 대부분의 응용 프로그램에서 잘 작동하지만, 때로는 다른 것들에 의해 사용되는 동안에만 객체를 추적해야 할 필요가 있습니다. 불행하게도, 단지 그것들을 추적하는 것만으로도 그들을 영구적으로 만드는 참조를 만듭니다. weakref 모듈은 참조를 만들지 않고 객체를 추적할 수 있는 도구를 제공합니다. 객체가 더 필요하지 않으면 weakref 테이블에서 객체가 자동으로 제거되고 weakref 객체에 대한 콜백이 트리거됩니다. 일반적인 응용에는 만드는 데 비용이 많이 드는 개체 캐싱이 포함됩니다:

>>> import weakref, gc
>>> class A:
...     def __init__(self, value):
...         self.value = value
...     def __repr__(self):
...         return str(self.value)
...
>>> a = A(10)                   # create a reference
>>> d = weakref.WeakValueDictionary()
>>> d['primary'] = a            # does not create a reference
>>> d['primary']                # fetch the object if it is still alive
10
>>> del a                       # remove the one reference
>>> gc.collect()                # run garbage collection right away
0
>>> d['primary']                # entry was automatically removed
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    d['primary']                # entry was automatically removed
  File "C:/python314/lib/weakref.py", line 46, in __getitem__
    o = self.data[key]()
KeyError: 'primary'

11.7. 리스트 작업 도구

내장 리스트 형으로 많은 데이터 구조 요구를 충족시킬 수 있습니다. 그러나 때로는 다른 성능 상충 관계가 있는 대안적 구현이 필요할 수도 있습니다.

The array module provides an array object that is like a list that stores only homogeneous data and stores it more compactly. The following example shows an array of numbers stored as two byte unsigned binary numbers (typecode "H") rather than the usual 16 bytes per entry for regular lists of Python int objects:

>>> from array import array
>>> a = array('H', [4000, 10, 700, 22222])
>>> sum(a)
26932
>>> a[1:3]
array('H', [10, 700])

The collections module provides a deque object that is like a list with faster appends and pops from the left side but slower lookups in the middle. These objects are well suited for implementing queues and breadth first tree searches:

>>> from collections import deque
>>> d = deque(["task1", "task2", "task3"])
>>> d.append("task4")
>>> print("Handling", d.popleft())
Handling task1

unsearched = deque([starting_node])
def breadth_first_search(unsearched):
    node = unsearched.popleft()
    for m in gen_moves(node):
        if is_goal(m):
            return m
        unsearched.append(m)

대안적 리스트 구현 외에도 라이브러리는 정렬된 리스트를 조작하는 함수들이 있는 bisect 모듈과 같은 다른 도구를 제공합니다:

>>> import bisect
>>> scores = [(100, 'perl'), (200, 'tcl'), (400, 'lua'), (500, 'python')]
>>> bisect.insort(scores, (300, 'ruby'))
>>> scores
[(100, 'perl'), (200, 'tcl'), (300, 'ruby'), (400, 'lua'), (500, 'python')]

heapq 모듈은 일반 리스트를 기반으로 힙을 구현하는 함수를 제공합니다. 가장 값이 작은 항목은 항상 위치 0에 유지됩니다. 이것은 가장 작은 요소에 반복적으로 액세스하지만, 전체 목록 정렬을 실행하지 않으려는 응용에 유용합니다:

>>> from heapq import heapify, heappop, heappush
>>> data = [1, 3, 5, 7, 9, 2, 4, 6, 8, 0]
>>> heapify(data)                      # rearrange the list into heap order
>>> heappush(data, -5)                 # add a new entry
>>> [heappop(data) for i in range(3)]  # fetch the three smallest entries
[-5, 0, 1]

11.8. Decimal Floating-Point Arithmetic

The decimal module offers a Decimal datatype for decimal floating-point arithmetic. Compared to the built-in float implementation of binary floating point, the class is especially helpful for

정확한 10진수 표현이 필요한 금융 응용 및 기타 용도,

정밀도 제어,

법적 또는 규제 요구 사항을 충족하는 반올림 제어,

유효숫자 추적, 또는

사용자가 결과가 손으로 계산한 것과 일치 할 것으로 기대하는 응용.

예를 들어, 70센트 전화 요금에 대해 5% 세금을 계산하면, 십진 부동 소수점 및 이진 부동 소수점에 다른 결과가 나타납니다. 결과를 가장 가까운 센트로 반올림하면 차이가 드러납니다:

>>> from decimal import *
>>> round(Decimal('0.70') * Decimal('1.05'), 2)
Decimal('0.74')
>>> round(.70 * 1.05, 2)
0.73

Decimal 결과는 끝에 붙는 0을 유지하며, 두 개의 유효숫자를 가진 피승수로부터 네 자리의 유효숫자를 자동으로 추론합니다. Decimal은 손으로 한 수학을 재현하고 이진 부동 소수점이 십진수를 정확하게 표현할 수 없을 때 발생할 수 있는 문제를 피합니다.

정확한 표현은 Decimal 클래스가 이진 부동 소수점에 적합하지 않은 모듈로 계산과 동등성 검사를 수행할 수 있도록 합니다:

>>> Decimal('1.00') % Decimal('.10')
Decimal('0.00')
>>> 1.00 % 0.10
0.09999999999999995

>>> sum([Decimal('0.1')]*10) == Decimal('1.0')
True
>>> 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 == 1.0
False

decimal 모듈은 필요한 만큼의 정밀도로 산술을 제공합니다:

>>> getcontext().prec = 36
>>> Decimal(1) / Decimal(7)
Decimal('0.142857142857142857142857142857142857')

12. 가상 환경 및 패키지

12.1. 소개

파이썬 응용 프로그램은 종종 표준 라이브러리의 일부로 제공되지 않는 패키지와 모듈을 사용합니다. 응용 프로그램에 특정 버전의 라이브러리가 필요할 수 있는데, 응용 프로그램에 특정 버그가 수정된 버전이 필요하거나, 라이브러리 인터페이스의 구식 버전을 사용하여 응용 프로그램을 작성할 수도 있기 때문입니다.

즉, 하나의 파이썬 설치가 모든 응용 프로그램의 요구 사항을 충족시키는 것이 불가능할 수도 있습니다. 응용 프로그램 A에 특정 모듈의 버전 1.0이 필요하지만, 응용 프로그램 B에 버전 2.0이 필요한 경우, 요구 사항이 충돌하고, 버전 1.0 또는 2.0을 설치하면 어느 한 응용 프로그램은 실행할 수 없게 됩니다.

이 문제에 대한 해결책은 가상 환경 을 만드는 것입니다. 이 가상 환경은 특정 버전 파이썬 설치와 여러 추가 패키지를 포함하는 완비된 디렉터리 트리입니다.

서로 다른 응용 프로그램은 서로 다른 가상 환경을 사용할 수 있습니다. 앞서 본 상충하는 요구 사항의 예를 해결하기 위해, 응용 프로그램 A에는 버전 1.0이 설치된 자체 가상 환경이 있고, 응용 프로그램 B에는 버전 2.0이 있는 다른 가상 환경이 있을 수 있습니다. 응용 프로그램 B에서 라이브러리를 버전 3.0으로 업그레이드해야 하는 경우, 응용 프로그램 A의 환경에 영향을 미치지 않습니다.

12.2. 가상 환경 만들기

The module used to create and manage virtual environments is called venv. venv will install the Python version from which the command was run (as reported by the --version option). For instance, executing the command with python3.12 will install version 3.12.

가상 환경을 만들려면, 원하는 디렉터리를 결정하고, venv 모듈을 스크립트로 실행하는데 디렉터리 경로를 명령행 인자로 전달합니다:

python -m venv tutorial-env

This will create the tutorial-env directory if it doesn’t exist, and also create directories inside it containing a copy of the Python interpreter and various supporting files.

가상 환경의 일반적인 디렉터리 위치는 .venv입니다. 이 이름은 디렉터리가 보통 셸에서 숨겨져 있도록 하므로, 디렉터리가 존재하는 이유를 설명하는 이름을 제공하면서도 방해받지 않습니다. 또한 일부 툴링(tooling)이 지원하는 .env 환경 변수 정의 파일과의 충돌을 방지합니다.

가상 환경을 만들었으면, 가상 환경을 활성화할 수 있습니다.

윈도우에서 이렇게 실행합니다:

tutorial-env\Scripts\activate

Unix 또는 MacOS에서 이렇게 실행합니다:

source tutorial-env/bin/activate

(이 스크립트는 bash 셸을 위해 작성된 것으로, csh 또는 fish 셸을 사용하는 경우에는, 대신 activate.csh 와 activate.fish 스크립트를 사용해야 합니다.)

가상 환경을 활성화하면, 셸의 프롬프트가 변경되어 사용 중인 가상 환경을 보여주고, 환경을 수정하여 python 을 실행하면 특정 버전의 파이썬이 실행되도록 합니다. 예를 들어:

$ source ~/envs/tutorial-env/bin/activate
(tutorial-env) $ python
Python 3.5.1 (default, May  6 2016, 10:59:36)
  ...
>>> import sys
>>> sys.path
['', '/usr/local/lib/python35.zip', ...,
'~/envs/tutorial-env/lib/python3.5/site-packages']
>>>

To deactivate a virtual environment, type:

deactivate

into the terminal.

12.3. pip로 패키지 관리하기

You can install, upgrade, and remove packages using a program called pip. By default pip will install packages from the Python Package Index [https://pypi.org]. You can browse the Python Package Index by going to it in your web browser.

pip has a number of subcommands: “install”, “uninstall”, “freeze”, etc. (Consult the 파이썬 모듈 설치하기 guide for complete documentation for pip.)

패키지 이름을 지정하여 최신 버전의 패키지를 설치할 수 있습니다:

(tutorial-env) $ python -m pip install novas
Collecting novas
  Downloading novas-3.1.1.3.tar.gz (136kB)
Installing collected packages: novas
  Running setup.py install for novas
Successfully installed novas-3.1.1.3

패키지 이름 뒤에 == 과 버전 번호를 붙여 특정 버전의 패키지를 설치할 수도 있습니다:

(tutorial-env) $ python -m pip install requests==2.6.0
Collecting requests==2.6.0
  Using cached requests-2.6.0-py2.py3-none-any.whl
Installing collected packages: requests
Successfully installed requests-2.6.0

If you re-run this command, pip will notice that the requested version is already installed and do nothing. You can supply a different version number to get that version, or you can run python -m pip install --upgrade to upgrade the package to the latest version:

(tutorial-env) $ python -m pip install --upgrade requests
Collecting requests
Installing collected packages: requests
  Found existing installation: requests 2.6.0
    Uninstalling requests-2.6.0:
      Successfully uninstalled requests-2.6.0
Successfully installed requests-2.7.0

python -m pip uninstall followed by one or more package names will remove the packages from the virtual environment.

python -m pip show will display information about a particular package:

(tutorial-env) $ python -m pip show requests
---
Metadata-Version: 2.0
Name: requests
Version: 2.7.0
Summary: Python HTTP for Humans.
Home-page: http://python-requests.org
Author: Kenneth Reitz
Author-email: me@kennethreitz.com
License: Apache 2.0
Location: /Users/akuchling/envs/tutorial-env/lib/python3.4/site-packages
Requires:

python -m pip list will display all of the packages installed in the virtual environment:

(tutorial-env) $ python -m pip list
novas (3.1.1.3)
numpy (1.9.2)
pip (7.0.3)
requests (2.7.0)
setuptools (16.0)

python -m pip freeze will produce a similar list of the installed packages, but the output uses the format that python -m pip install expects. A common convention is to put this list in a requirements.txt file:

(tutorial-env) $ python -m pip freeze > requirements.txt
(tutorial-env) $ cat requirements.txt
novas==3.1.1.3
numpy==1.9.2
requests==2.7.0

requirements.txt 는 버전 제어에 커밋되어 응용 프로그램 일부로 제공될 수 있습니다. 사용자는 install -r 로 모든 필요한 패키지를 설치할 수 있습니다:

(tutorial-env) $ python -m pip install -r requirements.txt
Collecting novas==3.1.1.3 (from -r requirements.txt (line 1))
  ...
Collecting numpy==1.9.2 (from -r requirements.txt (line 2))
  ...
Collecting requests==2.7.0 (from -r requirements.txt (line 3))
  ...
Installing collected packages: novas, numpy, requests
  Running setup.py install for novas
Successfully installed novas-3.1.1.3 numpy-1.9.2 requests-2.7.0

pip has many more options. Consult the 파이썬 모듈 설치하기 guide for complete documentation for pip. When you’ve written a package and want to make it available on the Python Package Index, consult the Python packaging user guide [https://packaging.python.org/en/latest/tutorials/packaging-projects/].

13. 이제 뭘 하지?

이 자습서를 읽어서 아마도 파이썬 사용에 관한 관심이 높아졌을 것입니다 — 실제 문제를 해결하기 위해 파이썬을 적용하려고 열망해야 합니다. 더 배우려면 어디로 가야 할까?

이 자습서는 파이썬의 문서 세트의 일부입니다. 세트의 다른 문서는 다음과 같습니다:

파이썬 표준 라이브러리:

You should browse through this manual, which gives complete (though terse) reference material about types, functions, and the modules in the standard library. The standard Python distribution includes a lot of additional code. There are modules to read Unix mailboxes, retrieve documents via HTTP, generate random numbers, parse command-line options, compress data, and many other tasks. Skimming through the Library Reference will give you an idea of what’s available.

파이썬 모듈 설치하기 는 다른 파이썬 사용자가 작성한 추가 모듈을 설치하는 방법을 설명합니다.

파이썬 언어 레퍼런스: 파이썬의 문법과 의미에 대한 자세한 설명. 읽기에 부담스럽지만, 언어 자체에 대한 완전한 안내서로서 유용합니다.

기타 파이썬 자료:

https://www.python.org: The major Python web site. It contains code, documentation, and pointers to Python-related pages around the web.

https://docs.python.org: 파이썬의 설명서에 빠르게 액세스할 수 있습니다.

https://pypi.org: 이전에 치즈 가게(Cheese Shop)로도 불렸던 [1] 파이썬 패키지 인덱스는 내려받을 수 있는 사용자 제작 파이썬 모듈의 색인입니다. 코드를 배포하기 시작하면 다른 사람들이 찾을 수 있도록 여기에 코드를 등록할 수 있습니다.

https://code.activestate.com/recipes/langs/python/: 파이썬 요리책(Python Cookbook)은 많은 코드 예제, 더 큰 모듈 및 유용한 스크립트 모음입니다. 특히 주목할만한 공헌들을 Python Cookbook (O’Reilly & Associates, ISBN 0-596-00797-3)이라는 제목의 책에 모았습니다.

https://pyvideo.org collects links to Python-related videos from conferences and user-group meetings.

https://scipy.org: Scientific Python 프로젝트에는 빠른 배열 계산 및 조작을 위한 모듈들과 선형 대수, 푸리에 변환, 비선형 솔버, 난수 분포, 통계 분석 등과 같은 여러 가지 패키지들이 포함되어 있습니다.

파이썬 관련 질문 및 문제 보고의 경우, 뉴스 그룹 comp.lang.python 에 게시하거나 python-list@python.org 의 메일링 리스트로 보낼 수 있습니다. 뉴스 그룹과 메일링 리스트는 게이트웨이로 연결되어 있으므로 하나에 게시된 메시지는 자동으로 다른 그룹으로 전달됩니다. 하루에 수백 건의 게시물이 올라옵니다. 질문하고, 질문에 답변하고, 새로운 기능을 제안하고, 새로운 모듈을 발표합니다. 메일링 리스트 저장소는 https://mail.python.org/pipermail/ 에 있습니다.

게시하기 전에 자주 나오는 질문들 (FAQ라고도 한다) 목록을 확인해야 합니다. FAQ는 반복적으로 나타나는 많은 질문에 대한 답을 제공하며, 이미 여러분의 문제에 대한 해결 방법을 담고 있을 수 있습니다.

각주

[1]

“Cheese Shop” 은 Monty Python의 스케치입니다: 고객이 치즈 가게에 들어가지만, 찾는 치즈가 무엇이건, 점원은 없다고 말합니다.

14. 대화형 입력 편집 및 히스토리 치환

일부 파이썬 인터프리터 버전은 Korn 셸 및 GNU Bash 셸에 있는 기능과 유사하게 현재 입력 줄 편집 및 히스토리 치환을 지원합니다. 이는 다양한 스타일의 편집을 지원하는 GNU Readline [https://tiswww.case.edu/php/chet/readline/rltop.html] 라이브러리를 사용하여 구현됩니다. 이 라이브러리에는 자체 설명서가 있고, 여기에서 반복하지는 않습니다.

14.1. 탭 완성 및 히스토리 편집

Completion of variable and module names is automatically enabled at interpreter startup so that the Tab key invokes the completion function; it looks at Python statement names, the current local variables, and the available module names. For dotted expressions such as string.a, it will evaluate the expression up to the final '.' and then suggest completions from the attributes of the resulting object. Note that this may execute application-defined code if an object with a __getattr__() method is part of the expression. The default configuration also saves your history into a file named .python_history in your user directory. The history will be available again during the next interactive interpreter session.

14.2. 대화형 인터프리터 대안

이 기능은 이전 버전의 인터프리터에 비교해 엄청난 발전입니다; 그러나, 몇 가지 희망 사항이 남아 있습니다: 이어지는 줄에서 적절한 들여쓰기가 제안된다면 좋을 것입니다 (파서는 다음에 들여쓰기 토큰이 필요한지 알고 있습니다). 완료 메커니즘은 인터프리터의 심볼 테이블을 사용할 수 있습니다. 매치되는 괄호, 따옴표 등을 검사 (또는 제안)하는 명령도 유용할 것입니다.

꽤 오랫동안 사용됐던 개선된 대화형 인터프리터는 IPython [https://ipython.org/] 인데, 탭 완성, 객체 탐색 및 고급 히스토리 관리 기능을 갖추고 있습니다. 또한, 철저하게 커스터마이즈해서 다른 응용 프로그램에 내장할 수 있습니다. 비슷한 또 다른 개선된 대화형 환경은 bpython [https://bpython-interpreter.org/] 입니다.

15. Floating-Point Arithmetic: Issues and Limitations

Floating-point numbers are represented in computer hardware as base 2 (binary) fractions. For example, the decimal fraction 0.625 has value 6/10 + 2/100 + 5/1000, and in the same way the binary fraction 0.101 has value 1/2 + 0/4 + 1/8. These two fractions have identical values, the only real difference being that the first is written in base 10 fractional notation, and the second in base 2.

불행히도, 대부분의 십진 소수는 정확하게 이진 소수로 표현될 수 없습니다. 결과적으로, 일반적으로 입력하는 십진 부동 소수점 숫자가 실제로 기계에 저장될 때는 이진 부동 소수점 수로 근사 될 뿐입니다.

이 문제는 먼저 밑 10에서 따져보는 것이 이해하기 쉽습니다. 분수 1/3을 생각해봅시다. 이 값을 십진 소수로 근사할 수 있습니다:

0.3

또는, 더 정확하게,

0.33

또는, 더 정확하게,

0.333

등등. 아무리 많은 자릿수를 적어도 결과가 정확하게 1/3이 될 수 없지만, 점점 더 1/3에 가까운 근사치가 됩니다.

같은 방식으로, 아무리 많은 자릿수의 숫자를 사용해도, 십진수 0.1은 이진 소수로 정확하게 표현될 수 없습니다. 이진법에서, 1/10은 무한히 반복되는 소수입니다

0.0001100110011001100110011001100110011001100110011...

유한 한 비트 수에서 멈추면, 근삿값을 얻게 됩니다. 오늘날 대부분 기계에서, float는 이진 분수로 근사 되는 데, 최상위 비트로부터 시작하는 53비트를 분자로 사용하고, 2의 거듭제곱 수를 분모로 사용합니다. 1/10의 경우, 이진 분수는 3602879701896397 / 2 ** 55 인데, 실제 값 1/10과 거의 같지만 정확히 같지는 않습니다.

Many users are not aware of the approximation because of the way values are displayed. Python only prints a decimal approximation to the true decimal value of the binary approximation stored by the machine. On most machines, if Python were to print the true decimal value of the binary approximation stored for 0.1, it would have to display:

>>> 0.1
0.1000000000000000055511151231257827021181583404541015625

That is more digits than most people find useful, so Python keeps the number of digits manageable by displaying a rounded value instead:

>>> 1 / 10
0.1

인쇄된 결과가 정확히 1/10인 것처럼 보여도, 실제 저장된 값은 가장 가까운 표현 가능한 이진 소수임을 기억하세요.

흥미롭게도, 가장 가까운 근사 이진 소수를 공유하는 여러 다른 십진수가 있습니다. 예를 들어, 0.1 과 0.10000000000000001 및 0.1000000000000000055511151231257827021181583404541015625 는 모두 3602879701896397 / 2 ** 55 로 근사 됩니다. 이 십진 값들이 모두 같은 근삿값을 공유하기 때문에 eval(repr(x)) == x 불변을 그대로 유지하면서 그중 하나를 표시할 수 있습니다.

역사적으로, 파이썬 프롬프트와 내장 repr() 함수는 유효 숫자 17개의 숫자인 0.10000000000000001 을 선택합니다. 파이썬 3.1부터, 이제 파이썬(대부분 시스템에서)이 가장 짧은 것을 선택할 수 있으며, 단순히 0.1 만 표시합니다.

Note that this is in the very nature of binary floating point: this is not a bug in Python, and it is not a bug in your code either. You’ll see the same kind of thing in all languages that support your hardware’s floating-point arithmetic (although some languages may not display the difference by default, or in all output modes).

For more pleasant output, you may wish to use string formatting to produce a limited number of significant digits:

>>> format(math.pi, '.12g')  # give 12 significant digits
'3.14159265359'

>>> format(math.pi, '.2f')   # give 2 digits after the point
'3.14'

>>> repr(math.pi)
'3.141592653589793'

이것이, 진정한 의미에서, 환영임을 깨닫는 것이 중요합니다: 여러분은 단순히 진짜 기곗값의 표시 를 반올림하고 있습니다.

One illusion may beget another. For example, since 0.1 is not exactly 1/10, summing three values of 0.1 may not yield exactly 0.3, either:

>>> 0.1 + 0.1 + 0.1 == 0.3
False

Also, since the 0.1 cannot get any closer to the exact value of 1/10 and 0.3 cannot get any closer to the exact value of 3/10, then pre-rounding with round() function cannot help:

>>> round(0.1, 1) + round(0.1, 1) + round(0.1, 1) == round(0.3, 1)
False

Though the numbers cannot be made closer to their intended exact values, the math.isclose() function can be useful for comparing inexact values:

>>> math.isclose(0.1 + 0.1 + 0.1, 0.3)
True

Alternatively, the round() function can be used to compare rough approximations:

>>> round(math.pi, ndigits=2) == round(22 / 7, ndigits=2)
True

Binary floating-point arithmetic holds many surprises like this. The problem with “0.1” is explained in precise detail below, in the “Representation Error” section. See Examples of Floating Point Problems [https://jvns.ca/blog/2023/01/13/examples-of-floating-point-problems/] for a pleasant summary of how binary floating point works and the kinds of problems commonly encountered in practice. Also see The Perils of Floating Point [http://www.indowsway.com/floatingpoint.htm] for a more complete account of other common surprises.

As that says near the end, “there are no easy answers.” Still, don’t be unduly wary of floating point! The errors in Python float operations are inherited from the floating-point hardware, and on most machines are on the order of no more than 1 part in 2**53 per operation. That’s more than adequate for most tasks, but you do need to keep in mind that it’s not decimal arithmetic and that every float operation can suffer a new rounding error.

병리학적 경우가 존재하지만, 무심히 부동 소수점 산술을 사용하는 대부분은, 단순히 최종 결과를 기대하는 자릿수로 반올림해서 표시하면 기대하는 결과를 보게 될 것입니다. 보통 str() 만으로도 충분하며, 더 세밀하게 제어하려면 포맷 문자열 문법 에서 str.format() 메서드의 포맷 지정자를 보세요.

정확한 십진 표현이 필요한 사용 사례의 경우, 회계 응용 프로그램 및 고정밀 응용 프로그램에 적합한 십진 산술을 구현하는 decimal 모듈을 사용해보세요.

정확한 산술의 또 다른 형태는 유리수를 기반으로 산술을 구현하는 fractions 모듈에 의해 지원됩니다 (따라서 1/3과 같은 숫자는 정확하게 나타낼 수 있습니다).

If you are a heavy user of floating-point operations you should take a look at the NumPy package and many other packages for mathematical and statistical operations supplied by the SciPy project. See <https://scipy.org>.

Python provides tools that may help on those rare occasions when you really do want to know the exact value of a float. The float.as_integer_ratio() method expresses the value of a float as a fraction:

>>> x = 3.14159
>>> x.as_integer_ratio()
(3537115888337719, 1125899906842624)

Since the ratio is exact, it can be used to losslessly recreate the original value:

>>> x == 3537115888337719 / 1125899906842624
True

The float.hex() method expresses a float in hexadecimal (base 16), again giving the exact value stored by your computer:

>>> x.hex()
'0x1.921f9f01b866ep+1'

This precise hexadecimal representation can be used to reconstruct the float value exactly:

>>> x == float.fromhex('0x1.921f9f01b866ep+1')
True

표현이 정확하므로, 파이썬의 다른 버전 에 걸쳐 값을 신뢰성 있게 이식하고 (플랫폼 독립성), 같은 형식을 지원하는 다른 언어(자바나 C99 같은)와 데이터를 교환하는 데 유용합니다.

Another helpful tool is the sum() function which helps mitigate loss-of-precision during summation. It uses extended precision for intermediate rounding steps as values are added onto a running total. That can make a difference in overall accuracy so that the errors do not accumulate to the point where they affect the final total:

>>> 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 == 1.0
False
>>> sum([0.1] * 10) == 1.0
True

The math.fsum() goes further and tracks all of the “lost digits” as values are added onto a running total so that the result has only a single rounding. This is slower than sum() but will be more accurate in uncommon cases where large magnitude inputs mostly cancel each other out leaving a final sum near zero:

>>> arr = [-0.10430216751806065, -266310978.67179024, 143401161448607.16,
...        -143401161400469.7, 266262841.31058735, -0.003244936839808227]
>>> float(sum(map(Fraction, arr)))   # Exact summation with single rounding
8.042173697819788e-13
>>> math.fsum(arr)                   # Single rounding
8.042173697819788e-13
>>> sum(arr)                         # Multiple roundings in extended precision
8.042178034628478e-13
>>> total = 0.0
>>> for x in arr:
...     total += x                   # Multiple roundings in standard precision
...
>>> total                            # Straight addition has no correct digits!
-0.0051575902860057365

15.1. 표현 오류

이 섹션에서는 “0.1” 예제를 자세히 설명하고, 이러한 사례에 대한 정확한 분석을 여러분이 직접 수행하는 방법을 보여줍니다. 이진 부동 소수점 표현에 대한 기본 지식이 있다고 가정합니다.

표현 오류 (Representation error) 는 일부 (실제로는, 대부분의) 십진 소수가 이진(밑 2) 소수로 정확하게 표현될 수 없다는 사실을 나타냅니다. 이것이 파이썬(또는 펄, C, C++, 자바, 포트란 및 기타 여러 언어)이 종종 여러분이 기대하는 정확한 십진수를 표시하지 않는 주된 이유입니다.

Why is that? 1/10 is not exactly representable as a binary fraction. Since at least 2000, almost all machines use IEEE 754 binary floating-point arithmetic, and almost all platforms map Python floats to IEEE 754 binary64 “double precision” values. IEEE 754 binary64 values contain 53 bits of precision, so on input the computer strives to convert 0.1 to the closest fraction it can of the form J/2**N where J is an integer containing exactly 53 bits. Rewriting

1 / 10 ~= J / (2**N)

를

J ~= 2**N / 10

and recalling that J has exactly 53 bits (is >= 2**52 but < 2**53), the best value for N is 56:

>>> 2**52 <=  2**56 // 10  < 2**53
True

That is, 56 is the only value for N that leaves J with exactly 53 bits. The best possible value for J is then that quotient rounded:

>>> q, r = divmod(2**56, 10)
>>> r
6

Since the remainder is more than half of 10, the best approximation is obtained by rounding up:

>>> q+1
7205759403792794

Therefore the best possible approximation to 1/10 in IEEE 754 double precision is:

7205759403792794 / 2 ** 56

분자와 분모를 둘로 나누면 다음과 같이 약분됩니다:

3602879701896397 / 2 ** 55

올림을 했기 때문에, 이것은 실제로 1/10 보다 약간 크다는 것에 유의하세요; 내림을 했다면, 몫이 1/10 보다 약간 작아졌을 것입니다. 그러나 어떤 경우에도 정확하게 1/10일 수는 없습니다!

So the computer never “sees” 1/10: what it sees is the exact fraction given above, the best IEEE 754 double approximation it can get:

>>> 0.1 * 2 ** 55
3602879701896397.0

If we multiply that fraction by 10**55, we can see the value out to 55 decimal digits:

>>> 3602879701896397 * 10 ** 55 // 2 ** 55
1000000000000000055511151231257827021181583404541015625

meaning that the exact number stored in the computer is equal to the decimal value 0.1000000000000000055511151231257827021181583404541015625. Instead of displaying the full decimal value, many languages (including older versions of Python), round the result to 17 significant digits:

>>> format(0.1, '.17f')
'0.10000000000000001'

The fractions and decimal modules make these calculations easy:

>>> from decimal import Decimal
>>> from fractions import Fraction

>>> Fraction.from_float(0.1)
Fraction(3602879701896397, 36028797018963968)

>>> (0.1).as_integer_ratio()
(3602879701896397, 36028797018963968)

>>> Decimal.from_float(0.1)
Decimal('0.1000000000000000055511151231257827021181583404541015625')

>>> format(Decimal.from_float(0.1), '.17')
'0.10000000000000001'

16. 부록

16.1. 대화형 모드

There are two variants of the interactive REPL. The classic basic interpreter is supported on all platforms with minimal line control capabilities.

On Windows, or Unix-like systems with curses support, a new interactive shell is used by default. This one supports color, multiline editing, history browsing, and paste mode. To disable color, see Controlling color for details. Function keys provide some additional functionality. F1 enters the interactive help browser pydoc. F2 allows for browsing command-line history with neither output nor the >>> and … prompts. F3 enters “paste mode”, which makes pasting larger blocks of code easier. Press F3 to return to the regular prompt.

When using the new interactive shell, exit the shell by typing exit or quit. Adding call parentheses after those commands is not required.

If the new interactive shell is not desired, it can be disabled via the PYTHON_BASIC_REPL environment variable.

16.1.1. 에러 처리

When an error occurs, the interpreter prints an error message and a stack trace. In interactive mode, it then returns to the primary prompt; when input came from a file, it exits with a nonzero exit status after printing the stack trace. (Exceptions handled by an except clause in a try statement are not errors in this context.) Some errors are unconditionally fatal and cause an exit with a nonzero exit status; this applies to internal inconsistencies and some cases of running out of memory. All error messages are written to the standard error stream; normal output from executed commands is written to standard output.

기본 또는 보조 프롬프트에 인터럽트 문자 (일반적으로 Control-C 또는 Delete)를 입력하면 입력을 취소하고 기본 프롬프트로 돌아갑니다. [1] 명령어가 실행되는 동안 인터럽트를 입력하면 try 문에 의해 처리될 수 있는 KeyboardInterrupt 예외가 발생합니다.

16.1.2. 실행 가능한 파이썬 스크립트

BSD 스타일의 유닉스 시스템에서 파이썬 스크립트는 셸 스크립트처럼 직접 실행할 수 있게 만들 수 있습니다. 다음과 같은 줄

#!/usr/bin/env python3

(인터프리터가 사용자의 PATH 에 있다고 가정할 때)을 스크립트의 시작 부분에 넣고 파일에 실행 가능 모드를 줍니다. #! 는 반드시 파일의 처음 두 문자여야 합니다. 일부 플랫폼에서는 이 첫 번째 줄이 유닉스 스타일의 줄 종료 ('\n')로 끝나야 하며, 윈도우 줄 종료('\r\n')는 허락되지 않습니다. 파이썬에서 해시, 또는 파운드, 문자 '#' 는 주석을 시작하는 데 사용됩니다.

스크립트는 chmod 명령을 사용하여 실행 가능한 모드, 또는 권한, 을 부여받을 수 있습니다.

$ chmod +x myscript.py

윈도우 시스템에서는 “실행 가능 모드”라는 개념이 없습니다. 파이썬 설치 프로그램은 .py 파일을 python.exe와 자동으로 연결하여, 파이썬 파일을 이중 클릭하면 스크립트로 실행합니다. 확장자는 .pyw 일 수도 있습니다. 이 경우, 일반적으로 나타나는 콘솔 창은 표시되지 않습니다.

16.1.3. 대화형 시작 파일

파이썬을 대화형으로 사용할 때, 종종 인터프리터가 시작될 때마다 실행되는 표준 명령들이 있으면 편리합니다. PYTHONSTARTUP 환경 변수를 시작 명령이 들어있는 파일 이름으로 설정하면 됩니다. 이것은 유닉스 셸의 .profile 기능과 유사합니다.

이 파일은 대화형 세션에서만 읽히며, 파이썬이 스크립트에서 명령을 읽을 때나, /dev/tty 가 명령의 명시적 소스인 경우(대화형 세션처럼 동작한다)에는 읽지 않습니다. 대화형 명령이 실행되는 같은 이름 공간에서 실행되므로, 이 파일에서 정의하거나 임포트하는 객체들을 대화형 세션에서 정규화하지 않은 이름으로 사용할 수 있습니다. 이 파일에서 sys.ps1 및 sys.ps2 프롬프트를 변경할 수도 있습니다.

현재 디렉터리에서 추가 시작 파일을 읽으려면, 전역 시작 파일에서 if os.path.isfile('.pythonrc.py'): exec(open('.pythonrc.py').read()) 와 같은 코드를 사용해서 프로그램할 수 있습니다. 스크립트에서 시작 파일을 사용하려면 스크립트에서 명시적으로 수행해야 합니다:

import os
filename = os.environ.get('PYTHONSTARTUP')
if filename and os.path.isfile(filename):
    with open(filename) as fobj:
        startup_file = fobj.read()
    exec(startup_file)

16.1.4. 커스터마이제이션 모듈

Python provides two hooks to let you customize it: sitecustomize and usercustomize. To see how it works, you need first to find the location of your user site-packages directory. Start Python and run this code:

>>> import site
>>> site.getusersitepackages()
'/home/user/.local/lib/python3.x/site-packages'

이제 그 디렉터리에 usercustomize.py 라는 이름의 파일을 만들고 원하는 것들을 넣을 수 있습니다. 자동 임포트를 비활성화하는 -s 옵션으로 시작하지 않는 한, 이 파일은 모든 파이썬 실행에 영향을 줍니다.

sitecustomize works in the same way, but is typically created by an administrator of the computer in the global site-packages directory, and is imported before usercustomize. See the documentation of the site module for more details.

각주

[1]

GNU Readline 패키지에 있는 문제가 이것을 방해할 수 있습니다.

파이썬 설정 및 사용법

설명서의 이 부분은 여러 플랫폼에서 파이썬 환경을 설정하고, 인터프리터를 호출하며, 파이썬으로 작업하기 더 쉽게 만드는 것들에 관한 일반적인 정보를 다루는데 할당되었습니다.

1. 명령 줄과 환경

1.1. 명령 줄

1.2. 환경 변수

2. 유닉스 플랫폼에서 파이썬 사용하기

2.1. 최신 버전의 파이썬 내려받기와 설치

2.2. 파이썬 빌드하기

2.3. 파이썬 관련 경로와 파일

2.4. 잡동사니

2.5. Custom OpenSSL

3. Configure Python

3.1. Build Requirements

3.2. Generated files

3.3. Configure Options

3.4. Python Build System

3.5. Compiler and linker flags

4. 윈도우에서 파이썬 사용하기

4.1. 전체 설치 프로그램

4.2. Microsoft Store 패키지

4.3. nuget.org 패키지

4.4. 내장 가능한 패키지

4.5. 대체 번들

4.6. 파이썬 구성하기

4.7. UTF-8 모드

4.8. 윈도우 용 파이썬 런처

4.9. 모듈 찾기

4.10. 추가 모듈

4.11. 윈도우에서 파이썬 컴파일하기

4.12. 기타 플랫폼

5. Using Python on macOS

5.1. Using Python for macOS from python.org

5.2. Alternative Distributions

5.3. 추가 파이썬 패키지 설치하기

5.4. GUI Programming

5.5. Advanced Topics

5.6. 기타 자원

6. Using Python on Android

6.1. Adding Python to an Android app

7. Using Python on iOS

7.1. Python at runtime on iOS

7.2. Installing Python on iOS

7.3. App Store Compliance

8. 편집기와 IDE

1. 명령 줄과 환경

CPython 인터프리터는 명령 줄과 환경에서 다양한 설정을 찾습니다.

CPython 구현 상세: 다른 구현의 명령 줄 체계는 다를 수 있습니다. 자세한 내용은 대안 구현들 참조하십시오.

1.1. 명령 줄

파이썬을 호출할 때 다음 옵션들을 지정할 수 있습니다:

python [-bBdEhiIOPqRsSuvVWx?] [-c command | -m module-name | script | - ] [args]

물론, 가장 일반적인 사용 사례는 간단한 스크립트 호출입니다:

python myscript.py

1.1.1. 인터페이스 옵션

인터프리터 인터페이스는 유닉스 셸의 인터페이스와 비슷하지만, 몇 가지 추가 호출 방법을 제공합니다:

When called with standard input connected to a tty device, it prompts for commands and executes them until an EOF (an end-of-file character, you can produce that with Ctrl-D on UNIX or Ctrl-Z, Enter on Windows) is read. For more on interactive mode, see 대화형 모드.

파일 이름 인자나 파일을 표준 입력으로 사용해서 호출하면, 해당 파일에서 스크립트를 읽고 실행합니다.

디렉터리 이름 인자로 호출되면, 해당 디렉터리에서 적절히 이름 붙은 스크립트를 읽고 실행합니다.

-c command 로 호출되면, command로 주어지는 파이썬 문장을 실행합니다. 여기서 command는 개행 문자로 구분된 여러 개의 문장을 포함할 수 있습니다. 선행 공백은 파이썬 문장에서 중요합니다!

-m module-name 으로 호출되면, 주어진 모듈을 파이썬 모듈 경로에서 찾은 후에 스크립트로 실행합니다.

비대화형 모드에서는, 실행하기 전에 전체 입력을 구문 분석합니다.

인터페이스 옵션은 인터프리터에 의해 소비되는 옵션의 목록을 종료합니다, 뒤따르는 모든 인자는 sys.argv 로 들어갑니다 – 첫 번째 요소, 서브 스크립트 0(sys.argv[0])은 프로그램 소스를 반영하는 문자열임에 유의하세요.

-c <command>

command 의 파이썬 코드를 실행합니다. command 는 개행 문자로 구분된 하나 이상의 문장일 수 있는데, 일반 모듈 코드에서와같이 선행 공백은 의미가 있습니다.

이 옵션을 주면, sys.argv 의 첫 번째 요소는 "-c" 가 되고, 현재 디렉터리를 sys.path 의 시작 부분에 추가합니다 (그 디렉터리에 있는 모듈을 최상위 모듈로 임포트 할 수 있게 합니다).

command를 인자로 감사 이벤트(auditing event) cpython.run_command를 발생시킵니다.

-m <module-name>

제공된 이름의 모듈을 sys.path 에서 검색하고 그 내용을 __main__ 모듈로서 실행합니다.

인자가 모듈 이름이기 때문에, 파일 확장자(.py)를 주지 않아야 합니다. 모듈 이름은 유효한 절대 파이썬 모듈 이름이어야 하지만, 구현이 항상 이를 강제하는 것은 아닙니다 (예를 들어, 하이픈을 포함하는 이름을 허락할 수도 있습니다).

패키지 이름(이름 공간 패키지 포함)도 허용됩니다. 일반 모듈 대신 패키지 이름이 제공되면, 인터프리터는 <pkg>.__main__ 을 메인 모듈로 실행합니다. 이 동작은 인터프리터에 스크립트 인자로 전달되는 디렉터리 및 zip 파일의 처리와 의도적으로 유사합니다.

참고

이 옵션은 내장 모듈이나 확장 모듈에는 사용될 수 없는데, 이것들은 파이썬 모듈 파일을 갖고 있지 않기 때문입니다. 그러나, 원래 소스 파일이 없는 사전 컴파일된 모듈에는 여전히 사용할 수 있습니다.

이 옵션을 주면, sys.argv 의 첫 번째 요소는 모듈 파일의 전체 경로가 됩니다 (모듈 파일을 찾는 동안에는 첫 번째 요소를 "-m" 으로 설정합니다). -c 옵션과 마찬가지로, 현재 디렉터리가 sys.path 의 시작 부분에 추가됩니다.

-I option can be used to run the script in isolated mode where sys.path contains neither the current directory nor the user’s site-packages directory. All PYTHON* environment variables are ignored, too.

많은 표준 라이브러리 모듈에는 스크립트로 실행할 때 호출되는 코드가 들어 있습니다. 한 예는 timeit 모듈입니다:

python -m timeit -s "setup here" "benchmarked code here"
python -m timeit -h # for details

module-name을 인자로 감사 이벤트(auditing event) cpython.run_module을 발생시킵니다.

더 보기

runpy.run_module()

파이썬 코드에서 직접 사용할 수 있는 동등한 기능

PEP 338 [https://peps.python.org/pep-0338/] – 모듈을 스크립트로 실행하기

버전 3.1에서 변경: __main__ 서브 모듈을 실행할 패키지 이름을 제공할 수 있습니다.

버전 3.4에서 변경: 이름 공간 패키지도 지원됩니다.

-

표준 입력(sys.stdin)에서 명령을 읽습니다. 표준 입력이 터미널이면, -i 가 묵시적으로 적용됩니다.

이 옵션을 주면, sys.argv 의 첫 번째 요소는 "-" 이 되고, 현재 디렉터리가 sys.path 의 처음에 추가됩니다.

인자 없이 감사 이벤트(auditing event) cpython.run_stdin을 발생시킵니다.

<script>

script 에 담긴 파이썬 코드를 실행합니다. script 는 파이썬 파일이나 __main__.py 파일이 들어있는 디렉터리나 __main__.py 파일을 포함하는 zip 파일을 가리키는 파일 시스템 경로(절대나 상대)여야 합니다.

이 옵션을 주면, sys.argv 의 첫 번째 요소는 명령 줄에서 주어진 스크립트 이름이 됩니다.

스크립트 이름이 파이썬 파일을 직접 가리키면, 해당 파일을 포함하는 디렉터리가 sys.path 의 시작 부분에 추가되고, 파일은 __main__ 모듈로 실행됩니다.

스크립트 이름이 디렉터리 나 zip 파일을 가리키면, 스크립트 이름이 sys.path 의 시작 부분에 추가되고, 해당 위치의 __main__.py 파일을 __main__ 모듈로 실행합니다.

-I option can be used to run the script in isolated mode where sys.path contains neither the script’s directory nor the user’s site-packages directory. All PYTHON* environment variables are ignored, too.

filename을 인자로 감사 이벤트(auditing event) cpython.run_file을 발생시킵니다.

더 보기

runpy.run_path()

파이썬 코드에서 직접 사용할 수 있는 동등한 기능

인터페이스 옵션을 주지 않으면, -i 가 묵시적으로 적용되고, sys.argv[0] 는 빈 문자열("")이 되고, 현재 디렉터리가 sys.path 의 처음에 추가됩니다. 또한, 플랫폼에서 사용 가능한 경우 (Readline 구성 를 참조하세요), 탭 완성 및 히스토리 편집이 자동으로 활성화됩니다.

더 보기

인터프리터 실행하기

버전 3.4에서 변경: 탭 완성과 히스토리 편집의 자동 활성화.

1.1.2. 일반 옵션

-?

-h

--help

Print a short description of all command line options and corresponding environment variables and exit.

--help-env

Print a short description of Python-specific environment variables and exit.

Added in version 3.11.

--help-xoptions

Print a description of implementation-specific -X options and exit.

Added in version 3.11.

--help-all

Print complete usage information and exit.

Added in version 3.11.

-V

--version

파이썬 버전 번호를 출력하고 종료합니다. 출력 예는 다음과 같습니다:

Python 3.8.0b2+

두 번 지정하면, 다음과 같이 빌드에 관한 추가 정보를 인쇄합니다:

Python 3.8.0b2+ (3.8:0c076caaa8, Apr 20 2019, 21:55:00)
[GCC 6.2.0 20161005]

Added in version 3.6: -VV 옵션.

1.1.3. 기타 옵션

-b

Issue a warning when converting bytes or bytearray to str without specifying encoding or comparing bytes or bytearray with str or bytes with int. Issue an error when the option is given twice (-bb).

버전 3.5에서 변경: Affects also comparisons of bytes with int.

-B

주어지면, 파이썬은 소스 모듈을 임포트 할 때 .pyc 파일을 쓰려고 하지 않습니다. PYTHONDONTWRITEBYTECODE 도 참조하십시오.

--check-hash-based-pycs default|always|never

해시 기반 .pyc 파일의 검증 동작을 제어합니다. 캐시된 바이트 코드 무효화를 참조하세요. default 로 설정하면, 검사형과 비검사형 해시 기반 바이트 코드 캐시 파일은 기본 의미에 따라 유효성이 검사됩니다. always 로 설정하면, 모든 해시 기반 .pyc 파일들은, 검사형과 비검사형을 가리지 않고, 해당 소스 파일에 대해 유효성이 검사됩니다. never 로 설정되면, 해시 기반 .pyc 파일은 해당 소스 파일에 대해 유효성이 검사되지 않습니다.

타임스탬프 기반 .pyc 파일의 의미는 이 옵션의 영향을 받지 않습니다.

-d

Turn on parser debugging output (for expert only). See also the PYTHONDEBUG environment variable.

This option requires a debug build of Python, otherwise it’s ignored.

-E

Ignore all PYTHON* environment variables, e.g. PYTHONPATH and PYTHONHOME, that might be set.

See also the -P and -I (isolated) options.

-i

Enter interactive mode after execution.

Using the -i option will enter interactive mode in any of the following circumstances:

When a script is passed as first argument

When the -c option is used

When the -m option is used

Interactive mode will start even when sys.stdin does not appear to be a terminal. The PYTHONSTARTUP file is not read.

이것은 스크립트가 예외를 발생시킬 때 전역 변수나 스택 트레이스를 검사하는 데 유용할 수 있습니다. PYTHONINSPECT 도 참조하십시오.

-I

Run Python in isolated mode. This also implies -E, -P and -s options.

In isolated mode sys.path contains neither the script’s directory nor the user’s site-packages directory. All PYTHON* environment variables are ignored, too. Further restrictions may be imposed to prevent the user from injecting malicious code.

Added in version 3.4.

-O

assert 문과 __debug__ 의 값에 대한 조건부 코드를 제거합니다. .pyc 확장자 앞에 .opt-1 을 추가하여 컴파일된 (바이트 코드) 파일의 이름을 구분합니다 (PEP 488 [https://peps.python.org/pep-0488/]을 참조하세요). PYTHONOPTIMIZE 도 참조하십시오.

버전 3.5에서 변경: PEP 488 [https://peps.python.org/pep-0488/] 에 따라 .pyc 파일명을 수정합니다.

-OO

-O를 적용하고 독스트링도 버립니다. .pyc 확장자 앞에 .opt-2 를 추가하여 컴파일 된(바이트 코드) 파일의 이름을 구분합니다 (참조 PEP 488 [https://peps.python.org/pep-0488/]을 참조하세요).

버전 3.5에서 변경: PEP 488 [https://peps.python.org/pep-0488/] 에 따라 .pyc 파일명을 수정합니다.

-P

Don’t prepend a potentially unsafe path to sys.path:

python -m module command line: Don’t prepend the current working directory.

python script.py command line: Don’t prepend the script’s directory. If it’s a symbolic link, resolve symbolic links.

python -c code and python (REPL) command lines: Don’t prepend an empty string, which means the current working directory.

See also the PYTHONSAFEPATH environment variable, and -E and -I (isolated) options.

Added in version 3.11.

-q

대화형 모드에서도 저작권과 버전 메시지를 표시하지 않습니다.

Added in version 3.2.

-R

해시 무작위화를 켭니다. 이 옵션은 PYTHONHASHSEED 환경 변수가 0 으로 설정된 경우에만 효과가 있습니다, 해시 무작위화는 기본적으로 활성화되기 때문입니다.

On previous versions of Python, this option turns on hash randomization, so that the __hash__() values of str and bytes objects are “salted” with an unpredictable random value. Although they remain constant within an individual Python process, they are not predictable between repeated invocations of Python.

Hash randomization is intended to provide protection against a denial-of-service caused by carefully chosen inputs that exploit the worst case performance of a dict construction, O(n²) complexity. See http://ocert.org/advisories/ocert-2011-003.html for details.

PYTHONHASHSEED 는 해시 시드 시크릿에 고정값을 설정할 수 있게 합니다.

Added in version 3.2.3.

버전 3.7에서 변경: 이 옵션은 더는 무시되지 않습니다.

-s

사용자 site-packages 디렉터리 를 sys.path 에 추가하지 않습니다.

See also PYTHONNOUSERSITE.

더 보기

PEP 370 [https://peps.python.org/pep-0370/] – 사용자별 site-packages 디렉터리

-S

site 모듈의 임포트와 이 모듈이 수반하는 sys.path 의 사이트 의존적 조작을 비활성화합니다. 또한 site 가 나중에 명시적으로 임포트될 때도 이 조작을 비활성화합니다 (조작하기를 원하면 site.main() 을 호출하십시오).

-u

stdout 과 stderr 스트림을 버퍼링하지 않도록 만듭니다. 이 옵션은 stdin 스트림에는 영향을 미치지 않습니다.

PYTHONUNBUFFERED 도 참조하세요.

버전 3.7에서 변경: stdout 과 stderr 스트림의 텍스트 계층은 이제 버퍼링 되지 않습니다.

-v

Print a message each time a module is initialized, showing the place (filename or built-in module) from which it is loaded. When given twice (-vv), print a message for each file that is checked for when searching for a module. Also provides information on module cleanup at exit.

버전 3.10에서 변경: The site module reports the site-specific paths and .pth files being processed.

See also PYTHONVERBOSE.

-W arg

Warning control. Python’s warning machinery by default prints warning messages to sys.stderr.

가장 단순한 설정은 프로세스가 만드는 모든 경고에 무조건 특정 액션을 적용합니다 (그렇지 않으면 기본적으로 무시되는 경고조차도):

-Wdefault  # Warn once per call location
-Werror    # Convert to exceptions
-Walways   # Warn every time
-Wall      # Same as -Walways
-Wmodule   # Warn once per calling module
-Wonce     # Warn once per Python process
-Wignore   # Never warn

The action names can be abbreviated as desired and the interpreter will resolve them to the appropriate action name. For example, -Wi is the same as -Wignore.

The full form of argument is:

action:message:category:module:lineno

Empty fields match all values; trailing empty fields may be omitted. For example -W ignore::DeprecationWarning ignores all DeprecationWarning warnings.

The action field is as explained above but only applies to warnings that match the remaining fields.

The message field must match the whole warning message; this match is case-insensitive.

The category field matches the warning category (ex: DeprecationWarning). This must be a class name; the match test whether the actual warning category of the message is a subclass of the specified warning category.

The module field matches the (fully qualified) module name; this match is case-sensitive.

The lineno field matches the line number, where zero matches all line numbers and is thus equivalent to an omitted line number.

Multiple -W options can be given; when a warning matches more than one option, the action for the last matching option is performed. Invalid -W options are ignored (though, a warning message is printed about invalid options when the first warning is issued).

Warnings can also be controlled using the PYTHONWARNINGS environment variable and from within a Python program using the warnings module. For example, the warnings.filterwarnings() function can be used to use a regular expression on the warning message.

자세한 내용은 경고 필터와 경고 필터 설명를 참조하십시오.

-x

소스의 첫 번째 줄을 건너 뛰어서, 유닉스 이외의 형식의 #!cmd 을 사용할 수 있게 합니다. 이것은 DOS 전용 핵(hack)을 위한 것입니다.

-X

다양한 구현 특정 옵션을 위해 예약되어 있습니다. CPython은 현재 다음과 같은 가능한 값을 정의합니다:

-X faulthandler to enable faulthandler. See also PYTHONFAULTHANDLER.

Added in version 3.3.

-X showrefcount to output the total reference count and number of used memory blocks when the program finishes or after each statement in the interactive interpreter. This only works on debug builds.

Added in version 3.4.

-X tracemalloc to start tracing Python memory allocations using the tracemalloc module. By default, only the most recent frame is stored in a traceback of a trace. Use -X tracemalloc=NFRAME to start tracing with a traceback limit of NFRAME frames. See tracemalloc.start() and PYTHONTRACEMALLOC for more information.

Added in version 3.4.

-X int_max_str_digits configures the integer string conversion length limitation. See also PYTHONINTMAXSTRDIGITS.

Added in version 3.11.

-X importtime 은 각 임포트가 얼마나 오래 걸렸는지 보여줍니다. 모듈 이름, 누적 시간(중첩된 임포트 포함), 자체 시간(중첩 임포트 제외)을 표시합니다. 다중 스레드 응용 프로그램에서 출력이 깨질 수 있음에 유의하십시오. 일반적인 사용법은 python3 -X importtime -c 'import asyncio' 입니다. PYTHONPROFILEIMPORTTIME 도 참조하십시오.

Added in version 3.7.

-X dev: enable Python Development Mode, introducing additional runtime checks that are too expensive to be enabled by default. See also PYTHONDEVMODE.

Added in version 3.7.

-X utf8 enables the Python UTF-8 Mode. -X utf8=0 explicitly disables Python UTF-8 Mode (even when it would otherwise activate automatically). See also PYTHONUTF8.

Added in version 3.7.

-X pycache_prefix=PATH는 .pyc 파일을 코드 트리 대신에 지정된 디렉터리를 루트로 하는 병렬 트리에 쓰도록 합니다. PYTHONPYCACHEPREFIX도 참조하십시오.

Added in version 3.8.

-X warn_default_encoding issues a EncodingWarning when the locale-specific default encoding is used for opening files. See also PYTHONWARNDEFAULTENCODING.

Added in version 3.10.

-X no_debug_ranges disables the inclusion of the tables mapping extra location information (end line, start column offset and end column offset) to every instruction in code objects. This is useful when smaller code objects and pyc files are desired as well as suppressing the extra visual location indicators when the interpreter displays tracebacks. See also PYTHONNODEBUGRANGES.

Added in version 3.11.

-X frozen_modules determines whether or not frozen modules are ignored by the import machinery. A value of on means they get imported and off means they are ignored. The default is on if this is an installed Python (the normal case). If it’s under development (running from the source tree) then the default is off. Note that the importlib_bootstrap and importlib_bootstrap_external frozen modules are always used, even if this flag is set to off. See also PYTHON_FROZEN_MODULES.

Added in version 3.11.

-X perf enables support for the Linux perf profiler. When this option is provided, the perf profiler will be able to report Python calls. This option is only available on some platforms and will do nothing if is not supported on the current system. The default value is “off”. See also PYTHONPERFSUPPORT and Python support for the Linux perf profiler.

Added in version 3.12.

-X perf_jit enables support for the Linux perf profiler with DWARF support. When this option is provided, the perf profiler will be able to report Python calls using DWARF information. This option is only available on some platforms and will do nothing if is not supported on the current system. The default value is “off”. See also PYTHON_PERF_JIT_SUPPORT and Python support for the Linux perf profiler.

Added in version 3.13.

-X cpu_count=n overrides os.cpu_count(), os.process_cpu_count(), and multiprocessing.cpu_count(). n must be greater than or equal to 1. This option may be useful for users who need to limit CPU resources of a container system. See also PYTHON_CPU_COUNT. If n is default, nothing is overridden.

Added in version 3.13.

-X presite=package.module specifies a module that should be imported before the site module is executed and before the __main__ module exists. Therefore, the imported module isn’t __main__. This can be used to execute code early during Python initialization. Python needs to be built in debug mode for this option to exist. See also PYTHON_PRESITE.

Added in version 3.13.

-X gil=0,1 forces the GIL to be disabled or enabled, respectively. Setting to 0 is only available in builds configured with --disable-gil. See also PYTHON_GIL and Free-threaded CPython.

Added in version 3.13.

또한 sys._xoptions 딕셔너리를 통해 임의의 값을 전달하고 조회할 수 있도록 합니다.

Added in version 3.2.

버전 3.9에서 변경: Removed the -X showalloccount option.

버전 3.10에서 변경: Removed the -X oldparser option.

1.1.4. Controlling color

The Python interpreter is configured by default to use colors to highlight output in certain situations such as when displaying tracebacks. This behavior can be controlled by setting different environment variables.

Setting the environment variable TERM to dumb will disable color.

If the FORCE_COLOR [https://force-color.org/] environment variable is set, then color will be enabled regardless of the value of TERM. This is useful on CI systems which aren’t terminals but can still display ANSI escape sequences.

If the NO_COLOR [https://no-color.org/] environment variable is set, Python will disable all color in the output. This takes precedence over FORCE_COLOR.

All these environment variables are used also by other tools to control color output. To control the color output only in the Python interpreter, the PYTHON_COLORS environment variable can be used. This variable takes precedence over NO_COLOR, which in turn takes precedence over FORCE_COLOR.

1.1.5. 사용해서는 안 되는 옵션

-J

Jython [https://www.jython.org/] 이 사용하기 위해 예약되었습니다.

1.2. 환경 변수

이 환경 변수들은 파이썬의 동작에 영향을 주며, -E와 -I 이외의 명령 줄 스위치보다 먼저 처리됩니다. 충돌하면 명령 줄 스위치가 환경 변수에 우선하는 것이 관례입니다.

PYTHONHOME

표준 파이썬 라이브러리의 위치를 변경합니다. 기본적으로, 라이브러리는 prefix/lib/pythonversion과 exec_prefix/lib/pythonversion에서 검색되는데, prefix 와 exec_prefix 는 설치 의존적인 디렉터리이고, 둘 다 기본값은 /usr/local 입니다.

PYTHONHOME 이 하나의 디렉터리로 설정되면, 그 값은 prefix 와 exec_prefix 를 모두 대체합니다. 이들에 대해 다른 값을 지정하려면, PYTHONHOME 을 prefix:exec_prefix 로 설정하십시오.

PYTHONPATH

모듈 파일의 기본 검색 경로를 보강합니다. 형식은 셸의 PATH 와 같습니다: 하나 이상의 디렉터리 경로명이 os.pathsep (예를 들어, 유닉스에서는 콜론, 윈도우에서는 세미콜론) 로 구분됩니다. 존재하지 않는 디렉터리는 조용히 무시됩니다.

일반 디렉터리 외에도, 개별 PYTHONPATH 엔트리는 순수 파이썬 모듈(소스 또는 컴파일된 형식)을 포함하는 zip 파일을 가리킬 수 있습니다. 확장 모듈은 zip 파일에서 임포트될 수 없습니다.

기본 검색 경로는 설치 의존적이지만, 일반적으로 prefix/lib/pythonversion으로 시작합니다 (위의 PYTHONHOME 을 참조하세요). 항상 PYTHONPATH 에 추가됩니다.

위에서 설명한 대로 인터페이스 옵션 하에서는 PYTHONPATH 앞에 검색 경로에 추가 디렉터리가 삽입됩니다. 검색 경로는 파이썬 프로그램 내에서 sys.path 변수로 조작할 수 있습니다.

PYTHONSAFEPATH

If this is set to a non-empty string, don’t prepend a potentially unsafe path to sys.path: see the -P option for details.

Added in version 3.11.

PYTHONPLATLIBDIR

이것을 비어 있지 않은 문자열로 설정하면, sys.platlibdir 값을 재정의합니다.

Added in version 3.9.

PYTHONSTARTUP

이것이 읽을 수 있는 파일의 이름이면, 첫 번째 프롬프트가 대화형 모드에 표시되기 전에, 해당 파일의 파이썬 명령이 실행됩니다. 이 파일은 대화형 명령이 실행되는 것과 같은 이름 공간에서 실행되므로, 여기에서 정의되거나 임포트 한 객체를 대화형 세션에서 그대로 사용할 수 있습니다. 이 파일에서 프롬프트 sys.ps1 과 sys.ps2 와 훅 sys.__interactivehook__ 도 바꿀 수 있습니다.

시작 시 호출될 때 filename을 인자로 감사 이벤트(auditing event) cpython.run_startup을 발생시킵니다.

PYTHONOPTIMIZE

비어 있지 않은 문자열로 설정하면 -O 옵션을 지정하는 것과 같습니다. 정수로 설정하면, -O를 여러 번 지정하는 것과 같습니다.

PYTHONBREAKPOINT

설정되면, 점으로 구분된 경로 표기법을 사용하여 콜러블의 이름을 지정합니다. 콜러블을 포함하는 모듈이 임포트 된 후에 콜러블은, 내장 breakpoint() 에 의해 호출되는 sys.breakpointhook() 의 기본 구현이 실행합니다. 설정되지 않았거나 빈 문자열로 설정하면, 값 “pdb.set_trace”와 동등합니다. 문자열 “0”으로 설정하면, sys.breakpointhook() 의 기본 구현은 아무것도 하지 않고 즉시 반환합니다.

Added in version 3.7.

PYTHONDEBUG

비어 있지 않은 문자열로 설정하면, -d 옵션을 지정하는 것과 같습니다. 정수로 설정하면, -d를 여러 번 지정하는 것과 같습니다.

This environment variable requires a debug build of Python, otherwise it’s ignored.

PYTHONINSPECT

비어 있지 않은 문자열로 설정하면, -i 옵션을 지정하는 것과 같습니다.

이 변수는 프로그램 종료 시 검사 모드를 강제하기 위해, os.environ 을 사용해서 파이썬 코드에 의해 수정될 수도 있습니다.

인자 없이 감사 이벤트(auditing event) cpython.run_stdin을 발생시킵니다.

버전 3.12.5에서 변경: (also 3.11.10, 3.10.15, 3.9.20, and 3.8.20) Emits audit events.

버전 3.13에서 변경: Uses PyREPL if possible, in which case PYTHONSTARTUP is also executed. Emits audit events.

PYTHONUNBUFFERED

비어 있지 않은 문자열로 설정하면, -u 옵션을 지정하는 것과 같습니다.

PYTHONVERBOSE

비어 있지 않은 문자열로 설정하면, -v 옵션을 지정하는 것과 같습니다. 정수로 설정하면 -v를 여러 번 지정하는 것과 같습니다.

PYTHONCASEOK

If this is set, Python ignores case in import statements. This only works on Windows and macOS.

PYTHONDONTWRITEBYTECODE

비어 있지 않은 문자열로 설정되면, 파이썬은 소스 모듈을 임포트 할 때 .pyc 파일을 쓰지 않습니다. 이는 -B 옵션을 지정하는 것과 같습니다.

PYTHONPYCACHEPREFIX

설정되면, 파이썬은 소스 트리 내의 __pycache__ 디렉터리 대신에 이 경로에 있는 미러 디렉터리 트리에 .pyc 파일을 씁니다. 이것은 -X pycache_prefix=PATH 옵션을 지정하는 것과 동등합니다.

Added in version 3.8.

PYTHONHASHSEED

이 변수가 설정되어 있지 않거나 random 으로 설정되면, str과 bytes 객체의 해시 시드에 난수가 사용됩니다.

PYTHONHASHSEED 가 정숫값으로 설정되면, 해시 무작위화가 적용되는 형의 hash()를 생성하기 위한 고정 시드로 사용됩니다.

목적은 인터프리터 자체에 대한 셀프 테스트와 같은 이유로 반복 가능한 해싱을 허용하거나, 파이썬 프로세스 클러스터가 해시값을 공유하도록 허용하는 것입니다.

정수는 [0,4294967295] 범위의 십진수여야 합니다. 값 0을 지정하면 해시 무작위화가 비활성화됩니다.

Added in version 3.2.3.

PYTHONINTMAXSTRDIGITS

If this variable is set to an integer, it is used to configure the interpreter’s global integer string conversion length limitation.

Added in version 3.11.

PYTHONIOENCODING

인터프리터를 실행하기 전에 이것이 설정되면, stdin/stdout/stderr에 사용되는 인코딩을 대체합니다. 문법은 encodingname:errorhandler 형식입니다. encodingname 과 :errorhandler 부분은 모두 선택 사항이며 str.encode() 에서와 같은 의미입니다.

stderr의 경우, :errorhandler 부분은 무시됩니다; 처리기는 항상 'backslashreplace' 입니다.

버전 3.4에서 변경: encodingname 부분은 이제 선택적입니다.

버전 3.6에서 변경: Windows에서, PYTHONLEGACYWINDOWSSTDIO 도 지정하지 않는 한, 대화형 콘솔 버퍼에서 이 변수로 지정된 인코딩이 무시됩니다. 표준 스트림을 통해 리디렉션 된 파일과 파이프는 영향을 받지 않습니다.

PYTHONNOUSERSITE

설정되면, 파이썬은 사용자 site-packages 디렉터리 를 sys.path 에 추가하지 않습니다.

더 보기

PEP 370 [https://peps.python.org/pep-0370/] – 사용자별 site-packages 디렉터리

PYTHONUSERBASE

Defines the user base directory, which is used to compute the path of the user site-packages directory and installation paths for python -m pip install --user.

더 보기

PEP 370 [https://peps.python.org/pep-0370/] – 사용자별 site-packages 디렉터리

PYTHONEXECUTABLE

If this environment variable is set, sys.argv[0] will be set to its value instead of the value got through the C runtime. Only works on macOS.

PYTHONWARNINGS

-W 옵션과 동등합니다. 쉼표로 구분된 문자열로 설정하면, -W를 여러 번 지정하는 것과 같습니다. 목록의 뒷부분에 있는 필터는 목록의 이전 필터보다 우선합니다.

가장 단순한 설정은 프로세스가 만드는 모든 경고에 무조건 특정 액션을 적용합니다 (그렇지 않으면 기본적으로 무시되는 경고조차도):

PYTHONWARNINGS=default  # Warn once per call location
PYTHONWARNINGS=error    # Convert to exceptions
PYTHONWARNINGS=always   # Warn every time
PYTHONWARNINGS=all      # Same as PYTHONWARNINGS=always
PYTHONWARNINGS=module   # Warn once per calling module
PYTHONWARNINGS=once     # Warn once per Python process
PYTHONWARNINGS=ignore   # Never warn

자세한 내용은 경고 필터와 경고 필터 설명를 참조하십시오.

PYTHONFAULTHANDLER

If this environment variable is set to a non-empty string, faulthandler.enable() is called at startup: install a handler for SIGSEGV, SIGFPE, SIGABRT, SIGBUS and SIGILL signals to dump the Python traceback. This is equivalent to -X faulthandler option.

Added in version 3.3.

PYTHONTRACEMALLOC

If this environment variable is set to a non-empty string, start tracing Python memory allocations using the tracemalloc module. The value of the variable is the maximum number of frames stored in a traceback of a trace. For example, PYTHONTRACEMALLOC=1 stores only the most recent frame. See the tracemalloc.start() function for more information. This is equivalent to setting the -X tracemalloc option.

Added in version 3.4.

PYTHONPROFILEIMPORTTIME

If this environment variable is set to a non-empty string, Python will show how long each import takes. This is equivalent to setting the -X importtime option.

Added in version 3.7.

PYTHONASYNCIODEBUG

이 환경 변수가 비어 있지 않은 문자열로 설정되면, asyncio 모듈의 디버그 모드 를 활성화합니다.

Added in version 3.4.

PYTHONMALLOC

파이썬 메모리 할당자를 설정하거나 디버그 훅을 설치합니다.

파이썬이 사용하는 메모리 할당자를 설정합니다:

default: 기본 메모리 할당자 를 사용합니다.

malloc: use the malloc() function of the C library for all domains (PYMEM_DOMAIN_RAW, PYMEM_DOMAIN_MEM, PYMEM_DOMAIN_OBJ).

pymalloc: use the pymalloc allocator for PYMEM_DOMAIN_MEM and PYMEM_DOMAIN_OBJ domains and use the malloc() function for the PYMEM_DOMAIN_RAW domain.

mimalloc: use the mimalloc allocator for PYMEM_DOMAIN_MEM and PYMEM_DOMAIN_OBJ domains and use the malloc() function for the PYMEM_DOMAIN_RAW domain.

Install debug hooks:

debug: 기본 메모리 할당자 위에 디버그 훅을 설치합니다.

malloc_debug: malloc 과 같지만, 디버그 훅도 설치합니다.

pymalloc_debug: pymalloc 과 같지만, 디버그 훅도 설치합니다.

mimalloc_debug: same as mimalloc but also install debug hooks.

Added in version 3.6.

버전 3.7에서 변경: "default" 할당자를 추가했습니다.

PYTHONMALLOCSTATS

비어 있지 않은 문자열로 설정되면, 파이썬은 새로운 pymalloc 객체 영역이 생성될 때마다, 그리고 종료할 때 pymalloc 메모리 할당자 의 통계를 인쇄합니다.

PYTHONMALLOC 환경 변수를 사용하여 C 라이브러리의 malloc() 할당자를 강제로 사용하거나, pymalloc 지원 없이 파이썬을 구성하면, 이 변수는 무시됩니다.

버전 3.6에서 변경: 이 변수는 이제 배포 모드로 컴파일된 파이썬에서도 사용할 수 있습니다. 이제 빈 문자열로 설정하면 효과가 없습니다.

PYTHONLEGACYWINDOWSFSENCODING

If set to a non-empty string, the default filesystem encoding and error handler mode will revert to their pre-3.6 values of ‘mbcs’ and ‘replace’, respectively. Otherwise, the new defaults ‘utf-8’ and ‘surrogatepass’ are used.

This may also be enabled at runtime with sys._enablelegacywindowsfsencoding().

Availability: Windows.

Added in version 3.6: 자세한 내용은 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오.

PYTHONLEGACYWINDOWSSTDIO

비어 있지 않은 문자열로 설정하면, 새 콘솔 입력기와 출력기를 사용하지 않습니다. 이것은 유니코드 문자가 utf-8을 사용하는 대신 활성 콘솔 코드 페이지에 따라 인코딩됨을 의미합니다.

이 변수는 표준 스트림이 콘솔 버퍼를 참조하는 대신 리디렉트 된 (파일 또는 파이프로) 경우 무시됩니다.

Availability: Windows.

Added in version 3.6.

PYTHONCOERCECLOCALE

값 0 으로 설정하면, 주 파이썬 명령 줄 응용 프로그램이 레거시 ASCII 기반 C와 POSIX 로케일을 보다 유능한 UTF-8 기반 대안으로 강제 변환하지 않습니다.

이 변수가 설정되지 않고 (또는 0 이외의 값으로 설정되고), 환경 변수에 우선하는 LC_ALL 로케일도 설정되지 않고, LC_CTYPE 범주에 대해 보고되는 현재 로케일이 기본 C 로케일이거나 명시적인 ASCII 기반의 POSIX 로케일이면, 파이썬 CLI는 인터프리터 런타임을 로드하기 전에 LC_CTYPE 범주에 대해 다음 로케일을 나열된 순서대로 구성하려고 시도합니다:

C.UTF-8

C.utf8

UTF-8

이러한 로케일 범주 중 하나를 설정하는 데 성공하면, 파이썬 런타임이 초기화되기 전에 LC_CTYPE 환경 변수도 현재 프로세스 환경에서 적절히 설정됩니다. 이렇게 하면 인터프리터 자신과 같은 프로세스에서 실행되는 다른 로케일 인식 구성 요소(가령 GNU readline 라이브러리)가 볼 수 있는 것에 더해, 갱신된 설정을 현재 C 로케일이 아닌 환경을 조회하는 연산(가령 파이썬 자체의 locale.getdefaultlocale())뿐만 아니라, 자식 프로세스에서도 (이 프로세스가 파이썬 인터프리터를 실행하는지에 관계없이) 볼 수 있습니다.

이러한 로케일 중 하나를 구성하면 (명시적으로나 위의 묵시적 로케일 강제 변경을 통해) sys.stdin 과 sys.stdout 에 대해 surrogateescape 에러 처리기 를 자동으로 활성화합니다 (sys.stderr 는 다른 로케일에서처럼 backslashreplace 를 계속 사용합니다). 이 스트림 처리 동작은 평소처럼 PYTHONIOENCODING을 사용하여 대체할 수 있습니다.

디버깅을 위해, PYTHONCOERCECLOCALE=warn 을 설정하면, 로케일 강제 변경이 일어나거나, 그렇지 않고 강제 변경을 유발할 로케일이 파이썬 런타임이 초기화될 때 여전히 활성 상태면 파이썬은 stderr 로 경고 메시지를 보냅니다.

또한, 로케일 강제 변환이 비활성화되거나 적절한 대상 로케일을 찾지 못할 때도, 레거시 ASCII 기반 로케일에서 PYTHONUTF8 은 기본적으로 활성화됨에 유의하십시오. 인터프리터가 시스템 인터페이스에 대해 UTF-8 대신에 ASCII 를 사용하게 하려면, 두 가지 기능을 모두 비활성화시켜야 합니다.

Availability: Unix.

Added in version 3.7: 자세한 내용은 PEP 538 [https://peps.python.org/pep-0538/]을 참조하십시오.

PYTHONDEVMODE

If this environment variable is set to a non-empty string, enable Python Development Mode, introducing additional runtime checks that are too expensive to be enabled by default. This is equivalent to setting the -X dev option.

Added in version 3.7.

PYTHONUTF8

If set to 1, enable the Python UTF-8 Mode.

If set to 0, disable the Python UTF-8 Mode.

다른 모든 비어 있지 않은 문자열로 설정하면, 인터프리터를 초기화하는 동안 에러가 발생합니다.

Added in version 3.7.

PYTHONWARNDEFAULTENCODING

If this environment variable is set to a non-empty string, issue a EncodingWarning when the locale-specific default encoding is used.

See Opt-in EncodingWarning for details.

Added in version 3.10.

PYTHONNODEBUGRANGES

If this variable is set, it disables the inclusion of the tables mapping extra location information (end line, start column offset and end column offset) to every instruction in code objects. This is useful when smaller code objects and pyc files are desired as well as suppressing the extra visual location indicators when the interpreter displays tracebacks.

Added in version 3.11.

PYTHONPERFSUPPORT

If this variable is set to a nonzero value, it enables support for the Linux perf profiler so Python calls can be detected by it.

If set to 0, disable Linux perf profiler support.

See also the -X perf command-line option and Python support for the Linux perf profiler.

Added in version 3.12.

PYTHON_PERF_JIT_SUPPORT

If this variable is set to a nonzero value, it enables support for the Linux perf profiler so Python calls can be detected by it using DWARF information.

If set to 0, disable Linux perf profiler support.

See also the -X perf_jit command-line option and Python support for the Linux perf profiler.

Added in version 3.13.

PYTHON_CPU_COUNT

If this variable is set to a positive integer, it overrides the return values of os.cpu_count() and os.process_cpu_count().

See also the -X cpu_count command-line option.

Added in version 3.13.

PYTHON_FROZEN_MODULES

If this variable is set to on or off, it determines whether or not frozen modules are ignored by the import machinery. A value of on means they get imported and off means they are ignored. The default is on for non-debug builds (the normal case) and off for debug builds. Note that the importlib_bootstrap and importlib_bootstrap_external frozen modules are always used, even if this flag is set to off.

See also the -X frozen_modules command-line option.

Added in version 3.13.

PYTHON_COLORS

If this variable is set to 1, the interpreter will colorize various kinds of output. Setting it to 0 deactivates this behavior. See also Controlling color.

Added in version 3.13.

PYTHON_BASIC_REPL

If this variable is set to 1, the interpreter will not attempt to load the Python-based REPL that requires curses and readline, and will instead use the traditional parser-based REPL.

Added in version 3.13.

PYTHON_HISTORY

This environment variable can be used to set the location of a .python_history file (by default, it is .python_history in the user’s home directory).

Added in version 3.13.

PYTHON_GIL

If this variable is set to 1, the global interpreter lock (GIL) will be forced on. Setting it to 0 forces the GIL off (needs Python configured with the --disable-gil build option).

See also the -X gil command-line option, which takes precedence over this variable, and Free-threaded CPython.

Added in version 3.13.

1.2.1. 디버그 모드 변수

PYTHONDUMPREFS

설정되면, 파이썬은 인터프리터를 종료한 후에도 살아있는 객체와 참조 횟수를 덤프합니다.

Needs Python configured with the --with-trace-refs build option.

PYTHONDUMPREFSFILE

If set, Python will dump objects and reference counts still alive after shutting down the interpreter into a file under the path given as the value to this environment variable.

Needs Python configured with the --with-trace-refs build option.

Added in version 3.11.

PYTHON_PRESITE

If this variable is set to a module, that module will be imported early in the interpreter lifecycle, before the site module is executed, and before the __main__ module is created. Therefore, the imported module is not treated as __main__.

This can be used to execute code early during Python initialization.

To import a submodule, use package.module as the value, like in an import statement.

See also the -X presite command-line option, which takes precedence over this variable.

Needs Python configured with the --with-pydebug build option.

Added in version 3.13.

2. 유닉스 플랫폼에서 파이썬 사용하기

2.1. 최신 버전의 파이썬 내려받기와 설치

2.1.1. 리눅스

Python comes preinstalled on most Linux distributions, and is available as a package on all others. However there are certain features you might want to use that are not available on your distro’s package. You can compile the latest version of Python from source.

In the event that the latest version of Python doesn’t come preinstalled and isn’t in the repositories as well, you can make packages for your own distro. Have a look at the following links:

더 보기

https://www.debian.org/doc/manuals/maint-guide/first.en.html

데비안 사용자용

https://en.opensuse.org/Portal:Packaging

OpenSuse 사용자용

https://docs.fedoraproject.org/en-US/package-maintainers/Packaging_Tutorial_GNU_Hello/

Fedora 사용자용

https://slackbook.org/html/package-management-making-packages.html

Slackware 사용자용

2.1.2. FreeBSD와 OpenBSD

FreeBSD 사용자, 패키지를 추가하려면 이렇게 하십시오:

pkg install python3

OpenBSD 사용자, 패키지를 추가하려면 이렇게 하십시오:

pkg_add -r python

pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/<insert your architecture here>/python-<version>.tgz

예를 들어 i386 사용자는 이렇게 파이썬 2.5.1 버전을 얻습니다:

pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/i386/python-2.5.1p2.tgz

2.2. 파이썬 빌드하기

If you want to compile CPython yourself, first thing you should do is get the source [https://www.python.org/downloads/source/]. You can download either the latest release’s source or just grab a fresh clone [https://devguide.python.org/setup/#get-the-source-code]. (If you want to contribute patches, you will need a clone.)

빌드 프로세스는 일반적으로 다음과 같은 명령으로 구성됩니다

./configure
make
make install

Configuration options and caveats for specific Unix platforms are extensively documented in the README.rst [https://github.com/python/cpython/tree/main/README.rst] file in the root of the Python source tree.

경고

make install은 python3 바이너리를 덮어쓰거나 가장 할 수 있습니다. 따라서 make altinstall을 make install 대신 권장하는데, exec_prefix/bin/pythonversion 만 설치하기 때문입니다.

2.3. 파이썬 관련 경로와 파일

These are subject to difference depending on local installation conventions; prefix and exec_prefix are installation-dependent and should be interpreted as for GNU software; they may be the same.

예를 들어, 대부분 리눅스 시스템에서, 기본값은 모두 /usr입니다.

파일/디렉터리

의미

exec_prefix/bin/python3

인터프리터의 권장 위치.

prefix/lib/pythonversion, exec_prefix/lib/pythonversion

표준 모듈을 포함하는 디렉터리의 권장 위치.

prefix/include/pythonversion, exec_prefix/include/pythonversion

파이썬 확장을 개발하고 인터프리터를 내장하는 데 필요한 인클루드 파일을 포함하는 디렉터리의 권장 위치.

2.4. 잡동사니

유닉스에서 파이썬 스크립트를 쉽게 사용하려면, 실행 파일로 만들어야 합니다. 예를 들어, 이렇게

$ chmod +x script

그리고, 스크립트의 상단에 적절한 셔뱅(Shebang) 줄을 넣습니다. 좋은 선택은 대개 이렇습니다

#!/usr/bin/env python3

이것은 PATH 전체에서 파이썬 인터프리터를 검색합니다. 그러나, 일부 유닉스에는 env 명령이 없을 수 있으므로, 인터프리터 경로로 /usr/bin/python3를 하드 코딩해야 할 수 있습니다.

파이썬 스크립트에서 셸 명령을 사용하려면, subprocess 모듈을 보십시오.

2.5. Custom OpenSSL

To use your vendor’s OpenSSL configuration and system trust store, locate the directory with openssl.cnf file or symlink in /etc. On most distribution the file is either in /etc/ssl or /etc/pki/tls. The directory should also contain a cert.pem file and/or a certs directory.

$ find /etc/ -name openssl.cnf -printf "%h\n"
/etc/ssl

Download, build, and install OpenSSL. Make sure you use install_sw and not install. The install_sw target does not override openssl.cnf.

$ curl -O https://www.openssl.org/source/openssl-VERSION.tar.gz
$ tar xzf openssl-VERSION
$ pushd openssl-VERSION
$ ./config \
    --prefix=/usr/local/custom-openssl \
    --libdir=lib \
    --openssldir=/etc/ssl
$ make -j1 depend
$ make -j8
$ make install_sw
$ popd

Build Python with custom OpenSSL (see the configure --with-openssl and --with-openssl-rpath options)

$ pushd python-3.x.x
$ ./configure -C \
    --with-openssl=/usr/local/custom-openssl \
    --with-openssl-rpath=auto \
    --prefix=/usr/local/python-3.x.x
$ make -j8
$ make altinstall

참고

Patch releases of OpenSSL have a backwards compatible ABI. You don’t need to recompile Python to update OpenSSL. It’s sufficient to replace the custom OpenSSL installation with a newer version.

3. Configure Python

3.1. Build Requirements

Features and minimum versions required to build CPython:

A C11 [https://en.cppreference.com/w/c/11] compiler. Optional C11 features [https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features] are not required.

On Windows, Microsoft Visual Studio 2017 or later is required.

Support for IEEE 754 [https://en.wikipedia.org/wiki/IEEE_754] floating-point numbers and floating-point Not-a-Number (NaN) [https://en.wikipedia.org/wiki/NaN#Floating_point].

Support for threads.

OpenSSL 1.1.1 is the minimum version and OpenSSL 3.0.9 is the recommended minimum version for the ssl and hashlib extension modules.

SQLite 3.15.2 for the sqlite3 extension module.

Tcl/Tk 8.5.12 for the tkinter module.

Autoconf 2.71 and aclocal 1.16.5 are required to regenerate the configure script.

버전 3.1에서 변경: Tcl/Tk version 8.3.1 is now required.

버전 3.5에서 변경: On Windows, Visual Studio 2015 or later is now required. Tcl/Tk version 8.4 is now required.

버전 3.6에서 변경: Selected C99 features are now required, like <stdint.h> and static inline functions.

버전 3.7에서 변경: Thread support and OpenSSL 1.0.2 are now required.

버전 3.10에서 변경: OpenSSL 1.1.1 is now required. Require SQLite 3.7.15.

버전 3.11에서 변경: C11 compiler, IEEE 754 and NaN support are now required. On Windows, Visual Studio 2017 or later is required. Tcl/Tk version 8.5.12 is now required for the tkinter module.

버전 3.13에서 변경: Autoconf 2.71, aclocal 1.16.5 and SQLite 3.15.2 are now required.

See also PEP 7 [https://peps.python.org/pep-0007/] “Style Guide for C Code” and PEP 11 [https://peps.python.org/pep-0011/] “CPython platform support”.

3.2. Generated files

To reduce build dependencies, Python source code contains multiple generated files. Commands to regenerate all generated files:

make regen-all
make regen-stdlib-module-names
make regen-limited-abi
make regen-configure

The Makefile.pre.in file documents generated files, their inputs, and tools used to regenerate them. Search for regen-* make targets.

3.2.1. configure script

The make regen-configure command regenerates the aclocal.m4 file and the configure script using the Tools/build/regen-configure.sh shell script which uses an Ubuntu container to get the same tools versions and have a reproducible output.

The container is optional, the following command can be run locally:

autoreconf -ivf -Werror

The generated files can change depending on the exact autoconf-archive, aclocal and pkg-config versions.

3.3. Configure Options

List all configure script options using:

./configure --help

See also the Misc/SpecialBuilds.txt in the Python source distribution.

3.3.1. General Options

--enable-loadable-sqlite-extensions

Support loadable extensions in the _sqlite extension module (default is no) of the sqlite3 module.

See the sqlite3.Connection.enable_load_extension() method of the sqlite3 module.

Added in version 3.6.

--disable-ipv6

Disable IPv6 support (enabled by default if supported), see the socket module.

--enable-big-digits=[15|30]

Define the size in bits of Python int digits: 15 or 30 bits.

By default, the digit size is 30.

Define the PYLONG_BITS_IN_DIGIT to 15 or 30.

See sys.int_info.bits_per_digit.

--with-suffix=SUFFIX

Set the Python executable suffix to SUFFIX.

The default suffix is .exe on Windows and macOS (python.exe executable), .js on Emscripten node, .html on Emscripten browser, .wasm on WASI, and an empty string on other platforms (python executable).

버전 3.11에서 변경: The default suffix on WASM platform is one of .js, .html or .wasm.

--with-tzpath=<list of absolute paths separated by pathsep>

Select the default time zone search path for zoneinfo.TZPATH. See the Compile-time configuration of the zoneinfo module.

Default: /usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo.

See os.pathsep path separator.

Added in version 3.9.

--without-decimal-contextvar

Build the _decimal extension module using a thread-local context rather than a coroutine-local context (default), see the decimal module.

See decimal.HAVE_CONTEXTVAR and the contextvars module.

Added in version 3.9.

--with-dbmliborder=<list of backend names>

Override order to check db backends for the dbm module

A valid value is a colon (:) separated string with the backend names:

ndbm;

gdbm;

bdb.

--without-c-locale-coercion

Disable C locale coercion to a UTF-8 based locale (enabled by default).

Don’t define the PY_COERCE_C_LOCALE macro.

See PYTHONCOERCECLOCALE and the PEP 538 [https://peps.python.org/pep-0538/].

--with-platlibdir=DIRNAME

Python library directory name (default is lib).

Fedora and SuSE use lib64 on 64-bit platforms.

See sys.platlibdir.

Added in version 3.9.

--with-wheel-pkg-dir=PATH

Directory of wheel packages used by the ensurepip module (none by default).

Some Linux distribution packaging policies recommend against bundling dependencies. For example, Fedora installs wheel packages in the /usr/share/python-wheels/ directory and don’t install the ensurepip._bundled package.

Added in version 3.10.

--with-pkg-config=[check|yes|no]

Whether configure should use pkg-config to detect build dependencies.

check (default): pkg-config is optional

yes: pkg-config is mandatory

no: configure does not use pkg-config even when present

Added in version 3.11.

--enable-pystats

Turn on internal Python performance statistics gathering.

By default, statistics gathering is off. Use python3 -X pystats command or set PYTHONSTATS=1 environment variable to turn on statistics gathering at Python startup.

At Python exit, dump statistics if statistics gathering was on and not cleared.

Effects:

Add -X pystats command line option.

Add PYTHONSTATS environment variable.

Define the Py_STATS macro.

Add functions to the sys module:

sys._stats_on(): Turns on statistics gathering.

sys._stats_off(): Turns off statistics gathering.

sys._stats_clear(): Clears the statistics.

sys._stats_dump(): Dump statistics to file, and clears the statistics.

The statistics will be dumped to a arbitrary (probably unique) file in /tmp/py_stats/ (Unix) or C:\temp\py_stats\ (Windows). If that directory does not exist, results will be printed on stderr.

Use Tools/scripts/summarize_stats.py to read the stats.

Statistics:

Opcode:

Specialization: success, failure, hit, deferred, miss, deopt, failures;

Execution count;

Pair count.

Call:

Inlined Python calls;

PyEval calls;

Frames pushed;

Frame object created;

Eval calls: vector, generator, legacy, function VECTORCALL, build class, slot, function “ex”, API, method.

Object:

incref and decref;

interpreter incref and decref;

allocations: all, 512 bytes, 4 kiB, big;

free;

to/from free lists;

dictionary materialized/dematerialized;

type cache;

optimization attempts;

optimization traces created/executed;

uops executed.

Garbage collector:

Garbage collections;

Objects visited;

Objects collected.

Added in version 3.11.

--disable-gil

Enables experimental support for running Python without the global interpreter lock (GIL): free threading build.

Defines the Py_GIL_DISABLED macro and adds "t" to sys.abiflags.

See Free-threaded CPython for more detail.

Added in version 3.13.

--enable-experimental-jit=[no|yes|yes-off|interpreter]

Indicate how to integrate the JIT compiler.

no - build the interpreter without the JIT.

yes - build the interpreter with the JIT.

yes-off - build the interpreter with the JIT but disable it by default.

interpreter - build the interpreter without the JIT, but with the tier 2 enabled interpreter.

By convention, --enable-experimental-jit is a shorthand for --enable-experimental-jit=yes.

Added in version 3.13.

PKG_CONFIG

Path to pkg-config utility.

PKG_CONFIG_LIBDIR

PKG_CONFIG_PATH

pkg-config options.

3.3.2. C compiler options

CC

C compiler command.

CFLAGS

C compiler flags.

CPP

C preprocessor command.

CPPFLAGS

C preprocessor flags, e.g. -Iinclude_dir.

3.3.3. Linker options

LDFLAGS

Linker flags, e.g. -Llibrary_directory.

LIBS

Libraries to pass to the linker, e.g. -llibrary.

MACHDEP

Name for machine-dependent library files.

3.3.4. Options for third-party dependencies

Added in version 3.11.

BZIP2_CFLAGS

BZIP2_LIBS

C compiler and linker flags to link Python to libbz2, used by bz2 module, overriding pkg-config.

CURSES_CFLAGS

CURSES_LIBS

C compiler and linker flags for libncurses or libncursesw, used by curses module, overriding pkg-config.

GDBM_CFLAGS

GDBM_LIBS

C compiler and linker flags for gdbm.

LIBB2_CFLAGS

LIBB2_LIBS

C compiler and linker flags for libb2 (BLAKE2), used by hashlib module, overriding pkg-config.

LIBEDIT_CFLAGS

LIBEDIT_LIBS

C compiler and linker flags for libedit, used by readline module, overriding pkg-config.

LIBFFI_CFLAGS

LIBFFI_LIBS

C compiler and linker flags for libffi, used by ctypes module, overriding pkg-config.

LIBMPDEC_CFLAGS

LIBMPDEC_LIBS

C compiler and linker flags for libmpdec, used by decimal module, overriding pkg-config.

참고

These environment variables have no effect unless --with-system-libmpdec is specified.

LIBLZMA_CFLAGS

LIBLZMA_LIBS

C compiler and linker flags for liblzma, used by lzma module, overriding pkg-config.

LIBREADLINE_CFLAGS

LIBREADLINE_LIBS

C compiler and linker flags for libreadline, used by readline module, overriding pkg-config.

LIBSQLITE3_CFLAGS

LIBSQLITE3_LIBS

C compiler and linker flags for libsqlite3, used by sqlite3 module, overriding pkg-config.

LIBUUID_CFLAGS

LIBUUID_LIBS

C compiler and linker flags for libuuid, used by uuid module, overriding pkg-config.

PANEL_CFLAGS

PANEL_LIBS

C compiler and linker flags for PANEL, overriding pkg-config.

C compiler and linker flags for libpanel or libpanelw, used by curses.panel module, overriding pkg-config.

TCLTK_CFLAGS

TCLTK_LIBS

C compiler and linker flags for TCLTK, overriding pkg-config.

ZLIB_CFLAGS

ZLIB_LIBS

C compiler and linker flags for libzlib, used by gzip module, overriding pkg-config.

3.3.5. WebAssembly Options

--enable-wasm-dynamic-linking

Turn on dynamic linking support for WASM.

Dynamic linking enables dlopen. File size of the executable increases due to limited dead code elimination and additional features.

Added in version 3.11.

--enable-wasm-pthreads

Turn on pthreads support for WASM.

Added in version 3.11.

3.3.6. Install Options

--prefix=PREFIX

Install architecture-independent files in PREFIX. On Unix, it defaults to /usr/local.

This value can be retrieved at runtime using sys.prefix.

As an example, one can use --prefix="$HOME/.local/" to install a Python in its home directory.

--exec-prefix=EPREFIX

Install architecture-dependent files in EPREFIX, defaults to --prefix.

This value can be retrieved at runtime using sys.exec_prefix.

--disable-test-modules

Don’t build nor install test modules, like the test package or the _testcapi extension module (built and installed by default).

Added in version 3.10.

--with-ensurepip=[upgrade|install|no]

Select the ensurepip command run on Python installation:

upgrade (default): run python -m ensurepip --altinstall --upgrade command.

install: run python -m ensurepip --altinstall command;

no: don’t run ensurepip;

Added in version 3.6.

3.3.7. Performance options

Configuring Python using --enable-optimizations --with-lto (PGO + LTO) is recommended for best performance. The experimental --enable-bolt flag can also be used to improve performance.

--enable-optimizations

Enable Profile Guided Optimization (PGO) using PROFILE_TASK (disabled by default).

The C compiler Clang requires llvm-profdata program for PGO. On macOS, GCC also requires it: GCC is just an alias to Clang on macOS.

Disable also semantic interposition in libpython if --enable-shared and GCC is used: add -fno-semantic-interposition to the compiler and linker flags.

참고

During the build, you may encounter compiler warnings about profile data not being available for some source files. These warnings are harmless, as only a subset of the code is exercised during profile data acquisition. To disable these warnings on Clang, manually suppress them by adding -Wno-profile-instr-unprofiled to CFLAGS.

Added in version 3.6.

버전 3.10에서 변경: Use -fno-semantic-interposition on GCC.

PROFILE_TASK

Environment variable used in the Makefile: Python command line arguments for the PGO generation task.

Default: -m test --pgo --timeout=$(TESTTIMEOUT).

Added in version 3.8.

버전 3.13에서 변경: Task failure is no longer ignored silently.

--with-lto=[full|thin|no|yes]

Enable Link Time Optimization (LTO) in any build (disabled by default).

The C compiler Clang requires llvm-ar for LTO (ar on macOS), as well as an LTO-aware linker (ld.gold or lld).

Added in version 3.6.

Added in version 3.11: To use ThinLTO feature, use --with-lto=thin on Clang.

버전 3.12에서 변경: Use ThinLTO as the default optimization policy on Clang if the compiler accepts the flag.

--enable-bolt

Enable usage of the BOLT post-link binary optimizer [https://github.com/llvm/llvm-project/tree/main/bolt] (disabled by default).

BOLT is part of the LLVM project but is not always included in their binary distributions. This flag requires that llvm-bolt and merge-fdata are available.

BOLT is still a fairly new project so this flag should be considered experimental for now. Because this tool operates on machine code its success is dependent on a combination of the build environment + the other optimization configure args + the CPU architecture, and not all combinations are supported. BOLT versions before LLVM 16 are known to crash BOLT under some scenarios. Use of LLVM 16 or newer for BOLT optimization is strongly encouraged.

The BOLT_INSTRUMENT_FLAGS and BOLT_APPLY_FLAGS configure variables can be defined to override the default set of arguments for llvm-bolt to instrument and apply BOLT data to binaries, respectively.

Added in version 3.12.

BOLT_APPLY_FLAGS

Arguments to llvm-bolt when creating a BOLT optimized binary [https://github.com/facebookarchive/BOLT].

Added in version 3.12.

BOLT_INSTRUMENT_FLAGS

Arguments to llvm-bolt when instrumenting binaries.

Added in version 3.12.

--with-computed-gotos

Enable computed gotos in evaluation loop (enabled by default on supported compilers).

--without-mimalloc

Disable the fast mimalloc allocator (enabled by default).

See also PYTHONMALLOC environment variable.

--without-pymalloc

Disable the specialized Python memory allocator pymalloc (enabled by default).

See also PYTHONMALLOC environment variable.

--without-doc-strings

Disable static documentation strings to reduce the memory footprint (enabled by default). Documentation strings defined in Python are not affected.

Don’t define the WITH_DOC_STRINGS macro.

See the PyDoc_STRVAR() macro.

--enable-profiling

Enable C-level code profiling with gprof (disabled by default).

--with-strict-overflow

Add -fstrict-overflow to the C compiler flags (by default we add -fno-strict-overflow instead).

3.3.8. Python Debug Build

A debug build is Python built with the --with-pydebug configure option.

Effects of a debug build:

Display all warnings by default: the list of default warning filters is empty in the warnings module.

Add d to sys.abiflags.

Add sys.gettotalrefcount() function.

Add -X showrefcount command line option.

Add -d command line option and PYTHONDEBUG environment variable to debug the parser.

Add support for the __lltrace__ variable: enable low-level tracing in the bytecode evaluation loop if the variable is defined.

Install debug hooks on memory allocators to detect buffer overflow and other memory errors.

Define Py_DEBUG and Py_REF_DEBUG macros.

Add runtime checks: code surrounded by #ifdef Py_DEBUG and #endif. Enable assert(...) and _PyObject_ASSERT(...) assertions: don’t set the NDEBUG macro (see also the --with-assertions configure option). Main runtime checks:

Add sanity checks on the function arguments.

Unicode and int objects are created with their memory filled with a pattern to detect usage of uninitialized objects.

Ensure that functions which can clear or replace the current exception are not called with an exception raised.

Check that deallocator functions don’t change the current exception.

The garbage collector (gc.collect() function) runs some basic checks on objects consistency.

The Py_SAFE_DOWNCAST() macro checks for integer underflow and overflow when downcasting from wide types to narrow types.

See also the Python Development Mode and the --with-trace-refs configure option.

버전 3.8에서 변경: Release builds and debug builds are now ABI compatible: defining the Py_DEBUG macro no longer implies the Py_TRACE_REFS macro (see the --with-trace-refs option).

3.3.9. Debug options

--with-pydebug

Build Python in debug mode: define the Py_DEBUG macro (disabled by default).

--with-trace-refs

Enable tracing references for debugging purpose (disabled by default).

Effects:

Define the Py_TRACE_REFS macro.

Add sys.getobjects() function.

Add PYTHONDUMPREFS environment variable.

The PYTHONDUMPREFS environment variable can be used to dump objects and reference counts still alive at Python exit.

Statically allocated objects are not traced.

Added in version 3.8.

버전 3.13에서 변경: This build is now ABI compatible with release build and debug build.

--with-assertions

Build with C assertions enabled (default is no): assert(...); and _PyObject_ASSERT(...);.

If set, the NDEBUG macro is not defined in the OPT compiler variable.

See also the --with-pydebug option (debug build) which also enables assertions.

Added in version 3.6.

--with-valgrind

Enable Valgrind support (default is no).

--with-dtrace

Enable DTrace support (default is no).

See Instrumenting CPython with DTrace and SystemTap.

Added in version 3.6.

--with-address-sanitizer

Enable AddressSanitizer memory error detector, asan (default is no).

Added in version 3.6.

--with-memory-sanitizer

Enable MemorySanitizer allocation error detector, msan (default is no).

Added in version 3.6.

--with-undefined-behavior-sanitizer

Enable UndefinedBehaviorSanitizer undefined behaviour detector, ubsan (default is no).

Added in version 3.6.

--with-thread-sanitizer

Enable ThreadSanitizer data race detector, tsan (default is no).

Added in version 3.13.

3.3.10. Linker options

--enable-shared

Enable building a shared Python library: libpython (default is no).

--without-static-libpython

Do not build libpythonMAJOR.MINOR.a and do not install python.o (built and enabled by default).

Added in version 3.10.

3.3.11. Libraries options

--with-libs='lib1 ...'

Link against additional libraries (default is no).

--with-system-expat

Build the pyexpat module using an installed expat library (default is no).

--with-system-libmpdec

Build the _decimal extension module using an installed mpdecimal library, see the decimal module (default is yes).

Added in version 3.3.

버전 3.13에서 변경: Default to using the installed mpdecimal library.

Deprecated since version 3.13, will be removed in version 3.15: A copy of the mpdecimal library sources will no longer be distributed with Python 3.15.

더 보기

LIBMPDEC_CFLAGS and LIBMPDEC_LIBS.

--with-readline=readline|editline

Designate a backend library for the readline module.

readline: Use readline as the backend.

editline: Use editline as the backend.

Added in version 3.10.

--without-readline

Don’t build the readline module (built by default).

Don’t define the HAVE_LIBREADLINE macro.

Added in version 3.10.

--with-libm=STRING

Override libm math library to STRING (default is system-dependent).

--with-libc=STRING

Override libc C library to STRING (default is system-dependent).

--with-openssl=DIR

Root of the OpenSSL directory.

Added in version 3.7.

--with-openssl-rpath=[no|auto|DIR]

Set runtime library directory (rpath) for OpenSSL libraries:

no (default): don’t set rpath;

auto: auto-detect rpath from --with-openssl and pkg-config;

DIR: set an explicit rpath.

Added in version 3.10.

3.3.12. Security Options

--with-hash-algorithm=[fnv|siphash13|siphash24]

Select hash algorithm for use in Python/pyhash.c:

siphash13 (default);

siphash24;

fnv.

Added in version 3.4.

Added in version 3.11: siphash13 is added and it is the new default.

--with-builtin-hashlib-hashes=md5,sha1,sha256,sha512,sha3,blake2

Built-in hash modules:

md5;

sha1;

sha256;

sha512;

sha3 (with shake);

blake2.

Added in version 3.9.

--with-ssl-default-suites=[python|openssl|STRING]

Override the OpenSSL default cipher suites string:

python (default): use Python’s preferred selection;

openssl: leave OpenSSL’s defaults untouched;

STRING: use a custom string

See the ssl module.

Added in version 3.7.

버전 3.10에서 변경: The settings python and STRING also set TLS 1.2 as minimum protocol version.

--disable-safety

Disable compiler options that are recommended by OpenSSF [https://github.com/ossf/wg-best-practices-os-developers/blob/main/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.md] for security reasons with no performance overhead. If this option is not enabled, CPython will be built based on safety compiler options with no slow down. When this option is enabled, CPython will not be built with the compiler options listed below.

The following compiler options are disabled with --disable-safety:

-fstack-protector-strong [https://github.com/ossf/wg-best-practices-os-developers/blob/main/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.md#enable-run-time-checks-for-stack-based-buffer-overflows]: Enable run-time checks for stack-based buffer overflows.

-Wtrampolines [https://github.com/ossf/wg-best-practices-os-developers/blob/main/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.md#enable-warning-about-trampolines-that-require-executable-stacks]: Enable warnings about trampolines that require executable stacks.

Added in version 3.14.

--enable-slower-safety

Enable compiler options that are recommended by OpenSSF [https://github.com/ossf/wg-best-practices-os-developers/blob/main/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.md] for security reasons which require overhead. If this option is not enabled, CPython will not be built based on safety compiler options which performance impact. When this option is enabled, CPython will be built with the compiler options listed below.

The following compiler options are enabled with --enable-slower-safety:

-D_FORTIFY_SOURCE=3 [https://github.com/ossf/wg-best-practices-os-developers/blob/main/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.md#fortify-sources-for-unsafe-libc-usage-and-buffer-overflows]: Fortify sources with compile- and run-time checks for unsafe libc usage and buffer overflows.

Added in version 3.14.

3.3.13. macOS Options

See Mac/README.rst [https://github.com/python/cpython/tree/main/Mac/README.rst].

--enable-universalsdk

--enable-universalsdk=SDKDIR

Create a universal binary build. SDKDIR specifies which macOS SDK should be used to perform the build (default is no).

--enable-framework

--enable-framework=INSTALLDIR

Create a Python.framework rather than a traditional Unix install. Optional INSTALLDIR specifies the installation path (default is no).

--with-universal-archs=ARCH

Specify the kind of universal binary that should be created. This option is only valid when --enable-universalsdk is set.

Options:

universal2;

32-bit;

64-bit;

3-way;

intel;

intel-32;

intel-64;

all.

--with-framework-name=FRAMEWORK

Specify the name for the python framework on macOS only valid when --enable-framework is set (default: Python).

--with-app-store-compliance

--with-app-store-compliance=PATCH-FILE

The Python standard library contains strings that are known to trigger automated inspection tool errors when submitted for distribution by the macOS and iOS App Stores. If enabled, this option will apply the list of patches that are known to correct app store compliance. A custom patch file can also be specified. This option is disabled by default.

Added in version 3.13.

3.3.14. iOS Options

See iOS/README.rst [https://github.com/python/cpython/tree/main/iOS/README.rst].

--enable-framework=INSTALLDIR

Create a Python.framework. Unlike macOS, the INSTALLDIR argument specifying the installation path is mandatory.

--with-framework-name=FRAMEWORK

Specify the name for the framework (default: Python).

3.3.15. Cross Compiling Options

Cross compiling, also known as cross building, can be used to build Python for another CPU architecture or platform. Cross compiling requires a Python interpreter for the build platform. The version of the build Python must match the version of the cross compiled host Python.

--build=BUILD

configure for building on BUILD, usually guessed by config.guess.

--host=HOST

cross-compile to build programs to run on HOST (target platform)

--with-build-python=path/to/python

path to build python binary for cross compiling

Added in version 3.11.

CONFIG_SITE=file

An environment variable that points to a file with configure overrides.

Example config.site file:

# config.site-aarch64
ac_cv_buggy_getaddrinfo=no
ac_cv_file__dev_ptmx=yes
ac_cv_file__dev_ptc=no

HOSTRUNNER

Program to run CPython for the host platform for cross-compilation.

Added in version 3.11.

Cross compiling example:

CONFIG_SITE=config.site-aarch64 ../configure \
    --build=x86_64-pc-linux-gnu \
    --host=aarch64-unknown-linux-gnu \
    --with-build-python=../x86_64/python

3.4. Python Build System

3.4.1. Main files of the build system

configure.ac => configure;

Makefile.pre.in => Makefile (created by configure);

pyconfig.h (created by configure);

Modules/Setup: C extensions built by the Makefile using Module/makesetup shell script;

3.4.2. Main build steps

C files (.c) are built as object files (.o).

A static libpython library (.a) is created from objects files.

python.o and the static libpython library are linked into the final python program.

C extensions are built by the Makefile (see Modules/Setup).

3.4.3. Main Makefile targets

3.4.3.1. make

For the most part, when rebuilding after editing some code or refreshing your checkout from upstream, all you need to do is execute make, which (per Make’s semantics) builds the default target, the first one defined in the Makefile. By tradition (including in the CPython project) this is usually the all target. The configure script expands an autoconf variable, @DEF_MAKE_ALL_RULE@ to describe precisely which targets make all will build. The three choices are:

profile-opt (configured with --enable-optimizations)

build_wasm (chosen if the host platform matches wasm32-wasi* or wasm32-emscripten)

build_all (configured without explicitly using either of the others)

Depending on the most recent source file changes, Make will rebuild any targets (object files and executables) deemed out-of-date, including running configure again if necessary. Source/target dependencies are many and maintained manually however, so Make sometimes doesn’t have all the information necessary to correctly detect all targets which need to be rebuilt. Depending on which targets aren’t rebuilt, you might experience a number of problems. If you have build or test problems which you can’t otherwise explain, make clean && make should work around most dependency problems, at the expense of longer build times.

3.4.3.2. make platform

Build the python program, but don’t build the standard library extension modules. This generates a file named platform which contains a single line describing the details of the build platform, e.g., macosx-14.3-arm64-3.12 or linux-x86_64-3.13.

3.4.3.3. make profile-opt

Build Python using profile-guided optimization (PGO). You can use the configure --enable-optimizations option to make this the default target of the make command (make all or just make).

3.4.3.4. make clean

Remove built files.

3.4.3.5. make distclean

In addition to the work done by make clean, remove files created by the configure script. configure will have to be run before building again. [1]

3.4.3.6. make install

Build the all target and install Python.

3.4.3.7. make test

Build the all target and run the Python test suite with the --fast-ci option without GUI tests. Variables:

TESTOPTS: additional regrtest command-line options.

TESTPYTHONOPTS: additional Python command-line options.

TESTTIMEOUT: timeout in seconds (default: 10 minutes).

3.4.3.8. make ci

This is similar to make test, but uses the -ugui to also run GUI tests.

Added in version 3.14.

3.4.3.9. make buildbottest

This is similar to make test, but uses the --slow-ci option and default timeout of 20 minutes, instead of --fast-ci option.

3.4.3.10. make regen-all

Regenerate (almost) all generated files. These include (but are not limited to) bytecode cases, and parser generator file. make regen-stdlib-module-names and autoconf must be run separately for the remaining generated files.

3.4.4. C extensions

Some C extensions are built as built-in modules, like the sys module. They are built with the Py_BUILD_CORE_BUILTIN macro defined. Built-in modules have no __file__ attribute:

>>> import sys
>>> sys
<module 'sys' (built-in)>
>>> sys.__file__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'sys' has no attribute '__file__'

Other C extensions are built as dynamic libraries, like the _asyncio module. They are built with the Py_BUILD_CORE_MODULE macro defined. Example on Linux x86-64:

>>> import _asyncio
>>> _asyncio
<module '_asyncio' from '/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'>
>>> _asyncio.__file__
'/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'

Modules/Setup is used to generate Makefile targets to build C extensions. At the beginning of the files, C extensions are built as built-in modules. Extensions defined after the *shared* marker are built as dynamic libraries.

The PyAPI_FUNC(), PyAPI_DATA() and PyMODINIT_FUNC macros of Include/exports.h are defined differently depending if the Py_BUILD_CORE_MODULE macro is defined:

Use Py_EXPORTED_SYMBOL if the Py_BUILD_CORE_MODULE is defined

Use Py_IMPORTED_SYMBOL otherwise.

If the Py_BUILD_CORE_BUILTIN macro is used by mistake on a C extension built as a shared library, its PyInit_xxx() function is not exported, causing an ImportError on import.

3.5. Compiler and linker flags

Options set by the ./configure script and environment variables and used by Makefile.

3.5.1. Preprocessor flags

CONFIGURE_CPPFLAGS

Value of CPPFLAGS variable passed to the ./configure script.

Added in version 3.6.

CPPFLAGS

(Objective) C/C++ preprocessor flags, e.g. -Iinclude_dir if you have headers in a nonstandard directory include_dir.

Both CPPFLAGS and LDFLAGS need to contain the shell’s value to be able to build extension modules using the directories specified in the environment variables.

BASECPPFLAGS

Added in version 3.4.

PY_CPPFLAGS

Extra preprocessor flags added for building the interpreter object files.

Default: $(BASECPPFLAGS) -I. -I$(srcdir)/Include $(CONFIGURE_CPPFLAGS) $(CPPFLAGS).

Added in version 3.2.

3.5.2. Compiler flags

CC

C compiler command.

Example: gcc -pthread.

CXX

C++ compiler command.

Example: g++ -pthread.

CFLAGS

C compiler flags.

CFLAGS_NODIST

CFLAGS_NODIST is used for building the interpreter and stdlib C extensions. Use it when a compiler flag should not be part of CFLAGS once Python is installed (gh-65320 [https://github.com/python/cpython/issues/65320]).

In particular, CFLAGS should not contain:

the compiler flag -I (for setting the search path for include files). The -I flags are processed from left to right, and any flags in CFLAGS would take precedence over user- and package-supplied -I flags.

hardening flags such as -Werror because distributions cannot control whether packages installed by users conform to such heightened standards.

Added in version 3.5.

COMPILEALL_OPTS

Options passed to the compileall command line when building PYC files in make install. Default: -j0.

Added in version 3.12.

EXTRA_CFLAGS

Extra C compiler flags.

CONFIGURE_CFLAGS

Value of CFLAGS variable passed to the ./configure script.

Added in version 3.2.

CONFIGURE_CFLAGS_NODIST

Value of CFLAGS_NODIST variable passed to the ./configure script.

Added in version 3.5.

BASECFLAGS

Base compiler flags.

OPT

Optimization flags.

CFLAGS_ALIASING

Strict or non-strict aliasing flags used to compile Python/dtoa.c.

Added in version 3.7.

CCSHARED

Compiler flags used to build a shared library.

For example, -fPIC is used on Linux and on BSD.

CFLAGSFORSHARED

Extra C flags added for building the interpreter object files.

Default: $(CCSHARED) when --enable-shared is used, or an empty string otherwise.

PY_CFLAGS

Default: $(BASECFLAGS) $(OPT) $(CONFIGURE_CFLAGS) $(CFLAGS) $(EXTRA_CFLAGS).

PY_CFLAGS_NODIST

Default: $(CONFIGURE_CFLAGS_NODIST) $(CFLAGS_NODIST) -I$(srcdir)/Include/internal.

Added in version 3.5.

PY_STDMODULE_CFLAGS

C flags used for building the interpreter object files.

Default: $(PY_CFLAGS) $(PY_CFLAGS_NODIST) $(PY_CPPFLAGS) $(CFLAGSFORSHARED).

Added in version 3.7.

PY_CORE_CFLAGS

Default: $(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE.

Added in version 3.2.

PY_BUILTIN_MODULE_CFLAGS

Compiler flags to build a standard library extension module as a built-in module, like the posix module.

Default: $(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE_BUILTIN.

Added in version 3.8.

PURIFY

Purify command. Purify is a memory debugger program.

Default: empty string (not used).

3.5.3. Linker flags

LINKCC

Linker command used to build programs like python and _testembed.

Default: $(PURIFY) $(CC).

CONFIGURE_LDFLAGS

Value of LDFLAGS variable passed to the ./configure script.

Avoid assigning CFLAGS, LDFLAGS, etc. so users can use them on the command line to append to these values without stomping the pre-set values.

Added in version 3.2.

LDFLAGS_NODIST

LDFLAGS_NODIST is used in the same manner as CFLAGS_NODIST. Use it when a linker flag should not be part of LDFLAGS once Python is installed (gh-65320 [https://github.com/python/cpython/issues/65320]).

In particular, LDFLAGS should not contain:

the compiler flag -L (for setting the search path for libraries). The -L flags are processed from left to right, and any flags in LDFLAGS would take precedence over user- and package-supplied -L flags.

CONFIGURE_LDFLAGS_NODIST

Value of LDFLAGS_NODIST variable passed to the ./configure script.

Added in version 3.8.

LDFLAGS

Linker flags, e.g. -Llib_dir if you have libraries in a nonstandard directory lib_dir.

Both CPPFLAGS and LDFLAGS need to contain the shell’s value to be able to build extension modules using the directories specified in the environment variables.

LIBS

Linker flags to pass libraries to the linker when linking the Python executable.

Example: -lrt.

LDSHARED

Command to build a shared library.

Default: @LDSHARED@ $(PY_LDFLAGS).

BLDSHARED

Command to build libpython shared library.

Default: @BLDSHARED@ $(PY_CORE_LDFLAGS).

PY_LDFLAGS

Default: $(CONFIGURE_LDFLAGS) $(LDFLAGS).

PY_LDFLAGS_NODIST

Default: $(CONFIGURE_LDFLAGS_NODIST) $(LDFLAGS_NODIST).

Added in version 3.8.

PY_CORE_LDFLAGS

Linker flags used for building the interpreter object files.

Added in version 3.8.

Footnotes

[1]

git clean -fdx is an even more extreme way to “clean” your checkout. It removes all files not known to Git. When bug hunting using git bisect, this is recommended between probes [https://github.com/python/cpython/issues/114505#issuecomment-1907021718] to guarantee a completely clean build. Use with care, as it will delete all files not checked into Git, including your new, uncommitted work.

4. 윈도우에서 파이썬 사용하기

이 문서는 Microsoft 윈도우에서 파이썬을 사용할 때 알아야 할 윈도우 특정 동작에 대한 개요를 제공하는 것을 목표로 합니다.

Unlike most Unix systems and services, Windows does not include a system supported installation of Python. To make Python available, the CPython team has compiled Windows installers with every release [https://www.python.org/downloads/] for many years. These installers are primarily intended to add a per-user installation of Python, with the core interpreter and library being used by a single user. The installer is also able to install for all users of a single machine, and a separate ZIP file is available for application-local distributions.

As specified in PEP 11 [https://peps.python.org/pep-0011/], a Python release only supports a Windows platform while Microsoft considers the platform under extended support. This means that Python 3.14 supports Windows 10 and newer. If you require Windows 7 support, please install Python 3.8. If you require Windows 8.1 support, please install Python 3.12.

윈도우에서 사용할 수 있는 여러 가지 설치 프로그램이 있으며, 각각 나름의 장단점이 있습니다.

전체 설치 프로그램은 모든 구성 요소를 포함하며 모든 종류의 프로젝트에 파이썬을 사용하는 개발자에게 가장 적합한 옵션입니다.

Microsoft Store 패키지 is a simple installation of Python that is suitable for running scripts and packages, and using IDLE or other development environments. It requires Windows 10 and above, but can be safely installed without corrupting other programs. It also provides many convenient commands for launching Python and its tools.

nuget.org 패키지는 지속적 통합 시스템(continuous integration systems)을 위한 경량 설치입니다. 파이썬 패키지를 빌드하거나 스크립트를 실행하는 데 사용할 수 있지만, 업데이트할 수 없으며 사용자 인터페이스 도구가 없습니다.

내장 가능한 패키지는 더 큰 응용 프로그램에 내장하기에 적합한 파이썬의 최소 패키지입니다.

4.1. 전체 설치 프로그램

4.1.1. 설치 단계

네 개의 파이썬 3.14 설치 프로그램을 다운로드할 수 있습니다 - 각각 32비트와 64비트 버전의 인터프리터를 지원하는 두 가지. 웹 설치 프로그램(web installer)은 작은 초기 다운로드이며, 필요한 구성 요소를 자동으로 다운로드합니다. 오프라인 설치 프로그램(offline installer)에는 기본 설치에 필요한 구성 요소가 포함되어 있으며 선택적 기능을 위해서만 인터넷 연결이 필요합니다. 설치 중 다운로드를 피하는 다른 방법은 다운로드 없이 설치하기를 참조하십시오.

설치 프로그램을 시작한 후, 두 가지 옵션 중 하나를 선택할 수 있습니다:

“Install Now”를 선택하면:

관리자(administrator)일 필요는 없습니다 (C 런타임 라이브러리에 대한 시스템 업데이트가 필요하거나 모든 사용자를 위해 윈도우 용 파이썬 런처를 설치하지 않는 한)

파이썬이 사용자 디렉터리에 설치됩니다

윈도우 용 파이썬 런처는 첫 페이지 하단의 옵션에 따라 설치됩니다

표준 라이브러리, 테스트 스위트, 런처 및 pip가 설치됩니다

선택하면, 설치 디렉터리가 PATH에 추가됩니다

바로 가기는 현재 사용자에게만 표시됩니다

“Customize installation”을 선택하면 설치할 기능, 설치 위치 및 다른 옵션이나 설치 후 작업을 선택할 수 있습니다. 디버깅 심볼이나 바이너리를 설치하려면, 이 옵션을 사용해야 합니다.

모든 사용자 설치를 수행하려면, “Customize installation”을 선택해야 합니다. 이 경우:

관리자 자격 증명이나 승인을 제공해야 할 수 있습니다.

파이썬은 Program Files 디렉터리에 설치됩니다

윈도우 용 파이썬 런처는 Windows 디렉터리에 설치됩니다

설치 중에 선택적 기능을 선택할 수 있습니다

표준 라이브러리는 바이트 코드로 사전 컴파일될 수 있습니다

선택하면, 설치 디렉터리가 시스템 PATH에 추가됩니다

모든 사용자가 바로 가기를 사용할 수 있습니다

4.1.2. MAX_PATH 제한 제거하기

윈도우는 역사적으로 경로 길이를 260자로 제한했습니다. 이는 이보다 긴 경로는 결정(resolve)되지 않고 에러가 발생함을 의미합니다.

최신 버전의 윈도우에서는, 이 제한을 약 32,000자로 확장할 수 있습니다. 관리자는 “Enable Win32 long paths” 그룹 정책을 활성화하거나, 레지스트리 키 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem에서 LongPathsEnabled를 1로 설정해야 합니다.

이는 open() 함수, os 모듈 및 대부분의 다른 경로 기능이 260자보다 긴 경로를 받아들이고 반환할 수 있도록 합니다.

위 옵션을 변경한 후에는, 추가 구성이 필요하지 않습니다.

버전 3.6에서 변경: 긴 경로에 대한 지원이 파이썬에서 활성화되었습니다.

4.1.3. UI 없이 설치하기

설치 프로그램 UI에서 사용할 수 있는 모든 옵션은 명령 줄에서도 지정할 수 있어서, 스크립팅 된 설치 프로그램이 사용자 상호 작용 없이 여러 컴퓨터에서 설치를 복제할 수 있도록 합니다. 이러한 옵션은 일부 기본값을 변경하기 위해 UI를 억제하지 않고 설정할 수도 있습니다.

The following options (found by executing the installer with /?) can be passed into the installer:

이름

설명

/passive

to display progress without requiring user interaction

/quiet

to install/uninstall without displaying any UI

/simple

to prevent user customization

/uninstall

to remove Python (without confirmation)

/layout [directory]

to pre-download all components

/log [filename]

to specify log files location

다른 모든 옵션은 name=value로 전달됩니다. 여기서 value는 일반적으로 기능을 비활성화하려면 0, 기능을 활성화하려면 1 또는 경로입니다. 사용 가능한 옵션의 전체 목록은 다음과 같습니다.

이름

설명

기본값

InstallAllUsers

시스템 전체 설치를 수행합니다.

0

TargetDir

설치 디렉터리

InstallAllUsers 에 따라 선택됩니다

DefaultAllUsersTargetDir

모든 사용자 설치를 위한 기본 설치 디렉터리

%ProgramFiles%\Python X.Y 또는 %ProgramFiles(x86)%\Python X.Y

DefaultJustForMeTargetDir

현재 사용자 전용 설치를 위한 기본 설치 디렉터리

%LocalAppData%\Programs\Python\PythonXY or %LocalAppData%\Programs\Python\PythonXY-32 or %LocalAppData%\Programs\Python\PythonXY-64

DefaultCustomTargetDir

UI에 표시되는 기본 사용자 지정 설치 디렉터리

(비어있음)

AssociateFiles

런처도 설치되었으면 파일 연결을 만듭니다.

1

CompileAll

모든 .py 파일을 .pyc로 컴파일합니다.

0

PrependPath

Prepend install and Scripts directories to PATH and add .PY to PATHEXT

0

AppendPath

Append install and Scripts directories to PATH and add .PY to PATHEXT

0

Shortcuts

설치되면, 인터프리터, 설명서 및 IDLE에 대한 바로 가기를 만듭니다.

1

Include_doc

파이썬 매뉴얼을 설치합니다

1

Include_debug

디버그 바이너리를 설치합니다

0

Include_dev

Install developer headers and libraries. Omitting this may lead to an unusable installation.

1

Include_exe

Install python.exe and related files. Omitting this may lead to an unusable installation.

1

Include_launcher

윈도우 용 파이썬 런처를 설치합니다.

1

InstallLauncherAllUsers

Installs the launcher for all users. Also requires Include_launcher to be set to 1

1

Include_lib

Install standard library and extension modules. Omitting this may lead to an unusable installation.

1

Include_pip

번들로 제공되는 pip와 setuptools를 설치합니다

1

Include_symbols

Install debugging symbols (*.pdb)

0

Include_tcltk

Tcl/Tk 지원과 IDLE을 설치합니다

1

Include_test

표준 라이브러리 테스트 스위트를 설치합니다

1

Include_tools

유틸리티 스크립트를 설치합니다

1

LauncherOnly

런처만 설치합니다. 이것은 대부분의 다른 옵션보다 우선합니다.

0

SimpleInstall

대부분의 설치 UI를 비활성화합니다

0

SimpleInstallDescription

단순화된 설치 UI를 사용할 때 표시할 사용자 정의 메시지.

(비어있음)

예를 들어 기본, 시스템 전체 파이썬 설치를 조용히 설치하려면, (관리자 권한 명령 프롬프트에서) 다음 명령을 사용할 수 있습니다:

python-3.9.0.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0

사용자가 테스트 스위트 없이 파이썬의 개인용 사본을 쉽게 설치할 수 있도록, 다음 명령으로 바로 가기를 제공할 수 있습니다. 이렇게 하면 단순화된 초기 페이지가 표시되고 사용자 정의가 허용되지 않습니다:

python-3.9.0.exe InstallAllUsers=0 Include_launcher=0 Include_test=0
    SimpleInstall=1 SimpleInstallDescription="Just for me, no test suite."

(런처를 생략하면 파일 연결도 생략되며, 런처가 포함된 시스템 전체 설치가 있을 때, 사용자별 설치에만 권장됨에 유의하십시오.)

위에 나열된 옵션은 실행 파일과 함께 unattend.xml이라는 파일로 제공될 수도 있습니다. 이 파일은 옵션과 값 목록을 지정합니다. 값이 어트리뷰트로 제공되면, 가능한 경우 숫자로 변환됩니다. 엘리먼트 텍스트로 제공된 값은 항상 문자열로 남아 있습니다. 이 예제 파일은 이전 예제와 같은 옵션을 설정합니다:

<Options>
    <Option Name="InstallAllUsers" Value="no" />
    <Option Name="Include_launcher" Value="0" />
    <Option Name="Include_test" Value="no" />
    <Option Name="SimpleInstall" Value="yes" />
    <Option Name="SimpleInstallDescription">Just for me, no test suite</Option>
</Options>

4.1.4. 다운로드 없이 설치하기

파이썬의 일부 기능은 초기 설치 프로그램 다운로드에 포함되어 있지 않아서, 이러한 기능을 선택하면 인터넷 연결이 필요할 수 있습니다. 이러한 요구를 피하고자, 필요에 따라 모든 가능한 구성 요소를 내려받아 선택한 기능과 관계없이 더는 인터넷 연결이 필요하지 않은 완전한 레이아웃을 만들 수 있습니다. 이 다운로드는 필요한 것보다 클 수 있지만, 많은 수의 설치를 수행할 경우 로컬로 캐시 된 사본을 보유하는 것이 매우 유용합니다.

가능한 모든 파일을 다운로드하려면 명령 프롬프트에서 다음 명령을 실행하십시오. python-3.9.0.exe를 설치 프로그램의 실제 이름으로 대체하고, 같은 이름을 가진 파일 간의 충돌을 방지하기 위해 자체 디렉터리에 레이아웃을 만들어야 합니다.

python-3.9.0.exe /layout [optional target directory]

/quiet 옵션을 지정하여 진행률 표시를 숨길 수도 있습니다.

4.1.5. 설치 수정하기

일단 파이썬이 설치되면, 윈도우의 일부인 Programs and Features 도구를 통해 기능을 추가하거나 제거할 수 있습니다. Python 항목을 선택하고 “Uninstall/Change”를 선택하여 유지 관리 모드로 설치 프로그램을 엽니다.

“Modify”는 체크 박스를 수정하여 기능을 추가하거나 제거하도록 합니다 - 변경되지 않은 체크 박스는 아무것도 설치하거나 제거하지 않습니다. 이 모드에서는 설치 디렉터리와 같은 일부 옵션을 변경할 수 없습니다; 이를 수정하려면 파이썬을 완전히 제거한 다음 다시 설치해야 합니다.

“Repair”는 현재 설정을 사용하여 설치되어야 하는 모든 파일을 확인하고 제거되거나 수정된 파일을 대체합니다.

“Uninstall”은 파이썬을 완전히 제거하는데, Programs and Features에 자체 항목이 있는 윈도우 용 파이썬 런처는 제외합니다.

4.1.6. Installing Free-threaded Binaries

Added in version 3.13: (Experimental)

참고

Everything described in this section is considered experimental, and should be expected to change in future releases.

To install pre-built binaries with free-threading enabled (see PEP 703 [https://peps.python.org/pep-0703/]), you should select “Customize installation”. The second page of options includes the “Download free-threaded binaries” checkbox.

Selecting this option will download and install additional binaries to the same location as the main Python install. The main executable is called python3.13t.exe, and other binaries either receive a t suffix or a full ABI suffix. Python source files and bundled third-party dependencies are shared with the main install.

The free-threaded version is registered as a regular Python install with the tag 3.13t (with a -32 or -arm64 suffix as normal for those platforms). This allows tools to discover it, and for the 윈도우 용 파이썬 런처 to support py.exe -3.13t. Note that the launcher will interpret py.exe -3 (or a python3 shebang) as “the latest 3.x install”, which will prefer the free-threaded binaries over the regular ones, while py.exe -3.13 will not. If you use the short style of option, you may prefer to not install the free-threaded binaries at this time.

To specify the install option at the command line, use Include_freethreaded=1. See 다운로드 없이 설치하기 for instructions on pre-emptively downloading the additional binaries for offline install. The options to include debug symbols and binaries also apply to the free-threaded builds.

Free-threaded binaries are also available on nuget.org.

4.2. Microsoft Store 패키지

Added in version 3.7.2.

Microsoft Store 패키지는 쉽게 설치할 수 있는 파이썬 인터프리터로, 주로 예를 들어 학생의 대화형 사용을 목적으로 합니다.

패키지를 설치하려면, 최신 윈도우 10 업데이트가 있는지 확인하고 “Python 3.14”를(을) 위한 Microsoft Store 앱을 검색하십시오. 선택한 앱이 Python Software Foundation에서 게시되었는지 확인하고, 설치합니다.

경고

파이썬은 Microsoft Store에서 항상 무료로 제공됩니다. 비용을 지불하라는 요청을 받으면, 올바른 패키지를 선택하지 않은 것입니다.

설치 후, 파이썬은 Start에서 찾아서 시작할 수 있습니다. 또는, 모든 명령 프롬프트 또는 PowerShell 세션에서 python을 입력하여 사용할 수 있습니다. 또한, pip나 idle을 입력하여 pip와 IDLE을 사용할 수 있습니다. IDLE은 Start에서도 찾을 수 있습니다.

세 가지 명령 모두 버전 번호 접미사와 함께 사용할 수 있습니다, 예를 들어, python.exe뿐만 아니라 python3.exe와 python3.x.exe (여기서 3.x는 여러분이 시작하려는 특정 버전입니다, 가령 3.14). Start를 통해 “Manage App Execution Aliases”를 열어 각 명령과 연결된 파이썬 버전을 선택합니다. pip와 idle이 선택된 python 버전과 일치하도록 하는 것이 좋습니다.

python -m venv로 가상 환경을 만들고 활성화하여 정상적으로 사용할 수 있습니다.

다른 버전의 파이썬을 설치하고 PATH 변수에 추가했으면, Microsoft Store에서 제공하는 것이 아니라 그것이 python.exe로 사용될 수 있습니다. 새 설치에 액세스하려면, python3.exe나 python3.x.exe를 사용하십시오.

py.exe 런처는 이 파이썬 설치를 감지하지만, 기존 설치 프로그램으로부터의 설치를 선호합니다.

파이썬을 제거하려면, Settings를 열고 Apps and Features를 사용하거나, Start에서 Python을 찾은 다음 마우스 오른쪽 단추를 클릭하여 Uninstall 을 선택합니다. 제거하면 이 파이썬 설치에 직접 설치한 모든 패키지가 제거되지만, 가상 환경은 제거되지 않습니다.

4.2.1. Known issues

4.2.1.1. Redirection of local data, registry, and temporary paths

Because of restrictions on Microsoft Store apps, Python scripts may not have full write access to shared locations such as TEMP and the registry. Instead, it will write to a private copy. If your scripts must modify the shared locations, you will need to install the full installer.

At runtime, Python will use a private copy of well-known Windows folders and the registry. For example, if the environment variable %APPDATA% is c:\Users\<user>\AppData\, then when writing to C:\Users\<user>\AppData\Local will write to C:\Users\<user>\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.8_qbz5n2kfra8p0\LocalCache\Local\.

When reading files, Windows will return the file from the private folder, or if that does not exist, the real Windows directory. For example reading C:\Windows\System32 returns the contents of C:\Windows\System32 plus the contents of C:\Program Files\WindowsApps\package_name\VFS\SystemX86.

You can find the real path of any existing file using os.path.realpath():

>>> import os
>>> test_file = 'C:\\Users\\example\\AppData\\Local\\test.txt'
>>> os.path.realpath(test_file)
'C:\\Users\\example\\AppData\\Local\\Packages\\PythonSoftwareFoundation.Python.3.8_qbz5n2kfra8p0\\LocalCache\\Local\\test.txt'

When writing to the Windows Registry, the following behaviors exist:

Reading from HKLM\\Software is allowed and results are merged with the registry.dat file in the package.

Writing to HKLM\\Software is not allowed if the corresponding key/value exists, i.e. modifying existing keys.

Writing to HKLM\\Software is allowed as long as a corresponding key/value does not exist in the package and the user has the correct access permissions.

For more detail on the technical basis for these limitations, please consult Microsoft’s documentation on packaged full-trust apps, currently available at docs.microsoft.com/en-us/windows/msix/desktop/desktop-to-uwp-behind-the-scenes [https://learn.microsoft.com/windows/msix/desktop/desktop-to-uwp-behind-the-scenes]

4.3. nuget.org 패키지

Added in version 3.5.2.

nuget.org 패키지는 시스템 전체에 파이썬이 설치되지 않은 지속적인 통합과 빌드 시스템에 사용하기 위한 축소된 크기의 파이썬 환경입니다. 너겟은 “.NET 용 패키지 관리자”이지만, 빌드 타임 도구가 포함된 패키지에서도 완벽하게 작동합니다.

너겟 사용에 대한 최신 정보를 보려면 nuget.org [https://www.nuget.org/]를 방문하십시오. 다음은 파이썬 개발자에게 충분한 요약입니다.

nuget.exe 명령 줄 도구는, 예를 들어 curl이나 PowerShell을 사용하여 https://aka.ms/nugetclidl에서 직접 다운로드할 수 있습니다. 이 도구를 사용하면 다음과 같이 64비트나 32비트 컴퓨터용 파이썬의 최신 버전이 설치됩니다:

nuget.exe install python -ExcludeVersion -OutputDirectory .
nuget.exe install pythonx86 -ExcludeVersion -OutputDirectory .

To select a particular version, add a -Version 3.x.y. The output directory may be changed from ., and the package will be installed into a subdirectory. By default, the subdirectory is named the same as the package, and without the -ExcludeVersion option this name will include the specific version installed. Inside the subdirectory is a tools directory that contains the Python installation:

# Without -ExcludeVersion
> .\python.3.5.2\tools\python.exe -V
Python 3.5.2

# With -ExcludeVersion
> .\python\tools\python.exe -V
Python 3.5.2

일반적으로, 너겟 패키지는 업그레이드할 수 없으며, 최신 버전을 나란히 설치하고 전체 경로를 사용하여 참조해야 합니다. 또는, 패키지 디렉터리를 수동으로 삭제하고 다시 설치하십시오. 많은 CI 시스템은 빌드 간에 파일을 보존하지 않으면 이 작업을 자동으로 수행합니다.

tools 디렉터리와 함께 build\native 디렉터리가 있습니다. 여기에는 파이썬 설치를 참조하기 위해 C++ 프로젝트에서 사용할 수 있는 MSBuild 속성 파일 python.props가 포함되어 있습니다. 설정을 포함하면 빌드에서 자동으로 헤더와 임포트 라이브러리를 사용합니다.

The package information pages on nuget.org are www.nuget.org/packages/python [https://www.nuget.org/packages/python] for the 64-bit version, www.nuget.org/packages/pythonx86 [https://www.nuget.org/packages/pythonx86] for the 32-bit version, and www.nuget.org/packages/pythonarm64 [https://www.nuget.org/packages/pythonarm64] for the ARM64 version

4.3.1. Free-threaded packages

Added in version 3.13: (Experimental)

참고

Everything described in this section is considered experimental, and should be expected to change in future releases.

Packages containing free-threaded binaries are named python-freethreaded [https://www.nuget.org/packages/python-freethreaded] for the 64-bit version, pythonx86-freethreaded [https://www.nuget.org/packages/pythonx86-freethreaded] for the 32-bit version, and pythonarm64-freethreaded [https://www.nuget.org/packages/pythonarm64-freethreaded] for the ARM64 version. These packages contain both the python3.13t.exe and python.exe entry points, both of which run free threaded.

4.4. 내장 가능한 패키지

Added in version 3.5.

내장된 배포는 최소 파이썬 환경을 포함하는 ZIP 파일입니다. 최종 사용자가 직접 액세스하기보다는, 다른 응용 프로그램의 일부로 작동하기 위한 것입니다.

When extracted, the embedded distribution is (almost) fully isolated from the user’s system, including environment variables, system registry settings, and installed packages. The standard library is included as pre-compiled and optimized .pyc files in a ZIP, and python3.dll, python37.dll, python.exe and pythonw.exe are all provided. Tcl/tk (including all dependents, such as Idle), pip and the Python documentation are not included.

참고

The embedded distribution does not include the Microsoft C Runtime [https://learn.microsoft.com/cpp/windows/latest-supported-vc-redist#visual-studio-2015-2017-2019-and-2022] and it is the responsibility of the application installer to provide this. The runtime may have already been installed on a user’s system previously or automatically via Windows Update, and can be detected by finding ucrtbase.dll in the system directory.

제삼자 패키지는 내장된 배포와 함께 응용 프로그램 설치 프로그램이 설치해야 합니다. 일반 파이썬 설치처럼 종속성을 관리하기 위해 pip를 사용하는 것은 이 배포에서 지원되지 않지만, 주의를 기울이면 자동 업데이트를 위해 pip를 포함하고 사용할 수 있습니다. 일반적으로, 제삼자 패키지는 개발자가 사용자에게 업데이트를 제공하기 전에 최신 버전과의 호환성을 보장할 수 있도록 응용 프로그램의 일부로 처리되어야 합니다 (“벤더링(vendoring)”).

이 배포에 권장되는 두 가지 사용 사례가 아래에 설명되어 있습니다.

4.4.1. 파이썬 응용 프로그램

파이썬으로 작성된 응용 프로그램이 반드시 사용자가 그 사실을 인식하도록 할 필요는 없습니다. 이 경우 내장된 배포를 사용하여 설치 패키지에 파이썬의 내부 버전을 포함할 수 있습니다. 얼마나 투명해야 하는지(또는 반대로, 얼마나 전문적으로 보여야 하는지)에 따라, 두 가지 옵션이 있습니다.

특수 실행 파일을 런처로 사용하려면 약간의 코딩이 필요하지만, 사용자에게 가장 투명한 경험을 제공합니다. 사용자 정의된 런처를 사용하면, 프로그램이 파이썬에서 실행되고 있다는 명백한 표시가 없습니다: 아이콘을 사용자 정의하고, 회사와 버전 정보를 지정할 수 있으며 파일 연결이 제대로 작동합니다. 대부분의 경우, 사용자 정의 런처는 하드 코딩된 명령 줄을 사용하여 Py_Main을 호출할 수 있어야 합니다.

더 간단한 방법은 필요한 명령 줄 인자를 사용하여 python.exe나 pythonw.exe를 직접 호출하는 배치 파일이나 생성된 바로 가기를 제공하는 것입니다. 이 경우, 응용 프로그램은 실제 이름이 아닌 파이썬으로 표시되며, 사용자는 실행 중인 다른 파이썬 프로세스나 파일 연결과 구별하는 데 어려움을 겪을 수 있습니다.

후자의 접근 방식에서는, 패키지를 파이썬 실행 파일과 함께 디렉터리로 설치하여 경로에서 사용할 수 있도록 해야 합니다. 특수 런처를 사용하면, 응용 프로그램을 시작하기 전에 검색 경로를 지정할 수 있어서 패키지를 다른 위치에 배치할 수 있습니다.

4.4.2. 파이썬 내장하기

네이티브 코드로 작성된 응용 프로그램에는 종종 어떤 형태의 스크립팅 언어가 필요하며, 내장된 파이썬 배포를 이러한 목적으로 사용할 수 있습니다. 일반적으로, 대부분의 응용 프로그램은 네이티브 코드로 되어 있으며, 일부가 python.exe를 호출하거나 python3.dll을 직접 사용합니다. 두 경우 모두, 내장된 배포를 응용 프로그램 설치의 하위 디렉터리로 추출하면 로드할 수 있는 파이썬 인터프리터를 제공하기에 충분합니다.

응용 프로그램 사용과 마찬가지로, 인터프리터를 초기화하기 전에 검색 경로를 지정할 기회가 있어서 패키지를 임의의 위치에 설치할 수 있습니다. 그 외에는, 내장된 배포와 일반 설치를 사용하는 것 간에 근본적인 차이점은 없습니다.

4.5. 대체 번들

표준 CPython 배포 외에도, 추가 기능을 포함하는 수정된 패키지가 있습니다. 다음은 많이 사용되는 버전과 주요 기능 목록입니다:

ActivePython [https://www.activestate.com/products/python/]

다중 플랫폼 호환성, 설명서, PyWin32가 있는 설치 프로그램

Anaconda [https://www.anaconda.com/download/]

인기 있는 과학 모듈(가령 numpy, scipy 및 pandas)과 conda 패키지 관리자.

Enthought Deployment Manager [https://assets.enthought.com/downloads/edm/]

“The Next Generation Python Environment and Package Manager”.

Previously Enthought provided Canopy, but it reached end of life in 2016 [https://support.enthought.com/hc/en-us/articles/360038600051-Canopy-GUI-end-of-life-transition-to-the-Enthought-Deployment-Manager-EDM-and-Visual-Studio-Code].

WinPython [https://winpython.github.io/]

사전 빌드된 과학 패키지와 패키지 빌드를 위한 도구가 포함된 윈도우 전용 배포.

이러한 패키지들은 최신 버전의 파이썬이나 기타 라이브러리를 포함하지 않을 수 있으며, 핵심 파이썬 팀에서 유지 관리하거나 지원하지 않음에 유의하십시오.

4.6. 파이썬 구성하기

명령 프롬프트에서 파이썬을 편리하게 실행하려면, 윈도우에서 일부 기본 환경 변수를 변경하는 것을 고려할 수 있습니다. 설치 프로그램이 PATH와 PATHEXT 변수를 구성하는 옵션을 제공하지만, 이는 시스템 전체의 단일 설치에서만 신뢰할 수 있습니다. 여러 버전의 파이썬을 정기적으로 사용하면, 윈도우 용 파이썬 런처 사용을 고려하십시오.

4.6.1. 보충 설명: 환경 변수 설정하기

윈도우에서는 환경 변수를 사용자 수준과 시스템 수준 모두에서 영구적으로 구성하거나, 명령 프롬프트에서 일시적으로 구성할 수 있습니다.

환경 변수를 임시로 설정하려면, 명령 프롬프트를 열고 set 명령을 사용하십시오:

C:\>set PATH=C:\Program Files\Python 3.9;%PATH%
C:\>set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib
C:\>python

이러한 변경은 해당 콘솔에서 실행되는 모든 추가 명령에 적용되며, 콘솔에서 시작된 모든 응용 프로그램에 상속됩니다.

백분율 기호 안에 변수 이름을 포함하면 기존 값으로 확장되어, 시작이나 끝부분에 새 값을 추가할 수 있습니다. python.exe를 포함하는 디렉터리를 시작 부분에 추가하여 PATH를 수정하는 것은 올바른 버전의 파이썬이 실행되도록 하는 일반적인 방법입니다.

기본 환경 변수를 영구적으로 수정하려면, Start를 클릭하고 ‘edit environment variables’를 검색하거나, 시스템 속성, Advanced system settings를 열고 Environment Variables 버튼을 클릭합니다. 이 대화 상자에서, 사용자와 시스템 변수를 추가하거나 수정할 수 있습니다. 시스템 변수를 변경하려면 컴퓨터에 제한 없이 액세스해야 합니다 (즉 관리자 권한).

참고

윈도우는 사용자 변수를 시스템 변수 뒤에 이어붙이므로, PATH를 수정할 때 예기치 않은 결과가 발생할 수 있습니다.

The PYTHONPATH variable is used by all versions of Python, so you should not permanently configure it unless the listed paths only include code that is compatible with all of your installed Python versions.

더 보기

https://learn.microsoft.com/windows/win32/procthread/environment-variables

Overview of environment variables on Windows

https://learn.microsoft.com/windows-server/administration/windows-commands/set_1

The set command, for temporarily modifying environment variables

https://learn.microsoft.com/windows-server/administration/windows-commands/setx

The setx command, for permanently modifying environment variables

4.6.2. 파이썬 실행 파일 찾기

버전 3.5에서 변경.

자동으로 만들어진 파이썬 인터프리터를 위한 시작 메뉴 항목을 사용하는 것 외에도, 명령 프롬프트에서 파이썬을 시작하고 싶을 수 있습니다. 설치 프로그램에는 이를 설정할 수 있는 옵션이 있습니다.

설치 프로그램의 첫 페이지에서, “Add Python to PATH”라는 옵션을 선택하여 설치 프로그램이 PATH에 설치 위치를 추가하도록 할 수 있습니다. Scripts\ 폴더의 위치도 추가됩니다. 이는 인터프리터를 실행하기 위해 python을 입력하고, 패키지 설치 프로그램을 실행하려면 pip를 입력할 수 있도록 합니다. 따라서, 명령 줄 옵션으로 스크립트를 실행할 수도 있습니다, 명령 줄 설명서를 참조하십시오.

설치 시 이 옵션을 활성화하지 않았으면, 언제든지 설치 프로그램을 다시 실행하고, Modify를 선택한 다음, 활성화할 수 있습니다. 또는, 보충 설명: 환경 변수 설정하기의 지침을 사용하여 PATH를 수동으로 수정할 수 있습니다. 파이썬 설치 디렉터리를 포함하도록 PATH 환경 변수를 설정해야 하며, 다른 항목과 세미콜론으로 구분됩니다. 예제 변수는 다음과 같습니다 (처음 두 항목이 이미 존재한다고 가정합니다):

C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Python 3.9

4.7. UTF-8 모드

Added in version 3.7.

Windows still uses legacy encodings for the system encoding (the ANSI Code Page). Python uses it for the default encoding of text files (e.g. locale.getencoding()).

UTF-8은 인터넷과 WSL(Windows Subsystem for Linux)을 포함한 대부분의 유닉스 시스템에서 널리 사용되기 때문에 문제가 발생할 수 있습니다.

You can use the Python UTF-8 Mode to change the default text encoding to UTF-8. You can enable the Python UTF-8 Mode via the -X utf8 command line option, or the PYTHONUTF8=1 environment variable. See PYTHONUTF8 for enabling UTF-8 mode, and 보충 설명: 환경 변수 설정하기 for how to modify environment variables.

When the Python UTF-8 Mode is enabled, you can still use the system encoding (the ANSI Code Page) via the “mbcs” codec.

기본 환경 변수에 PYTHONUTF8=1을 추가하면 시스템의 모든 파이썬 3.7+ 응용 프로그램에 영향을 줍니다. 레거시 시스템 인코딩에 의존하는 파이썬 3.7+ 응용 프로그램이 있으면 환경 변수를 임시로 설정하거나 -X utf8 명령 줄 옵션을 사용하는 것이 좋습니다.

참고

UTF-8 모드가 비활성화된 경우에도, 파이썬은 윈도우에서 기본적으로 다음을 위해 UTF-8을 사용합니다:

표준 I/O를 포함한 콘솔 I/O (자세한 내용은 PEP 528 [https://peps.python.org/pep-0528/]을 참조하십시오).

The filesystem encoding (see PEP 529 [https://peps.python.org/pep-0529/] for details).

4.8. 윈도우 용 파이썬 런처

Added in version 3.3.

윈도우 용 파이썬 런처는 다양한 파이썬 버전을 찾고 실행하는 데 도움이 되는 유틸리티입니다. 스크립트(또는 명령 줄)가 특정 파이썬 버전에 대한 선호를 나타내도록 허용하고, 해당 버전을 찾아 실행합니다.

PATH 변수와 달리, 런처는 가장 적합한 파이썬 버전을 올바르게 선택합니다. 시스템 전체 설치보다 사용자별 설치를 선호하며, 가장 최근에 설치된 버전을 사용하기보다 언어 버전별로 순서를 매깁니다.

런처는 원래 PEP 397 [https://peps.python.org/pep-0397/]에서 지정되었습니다.

4.8.1. 시작하기

4.8.1.1. 명령 줄에서

버전 3.6에서 변경.

System-wide installations of Python 3.3 and later will put the launcher on your PATH. The launcher is compatible with all available versions of Python, so it does not matter which version is installed. To check that the launcher is available, execute the following command in Command Prompt:

py

설치한 최신 버전의 파이썬이 시작되어야 합니다 - 정상적으로 종료할 수 있으며, 지정된 추가 명령 줄 인자가 파이썬으로 직접 전송됩니다.

If you have multiple versions of Python installed (e.g., 3.7 and 3.14) you will have noticed that Python 3.14 was started - to launch Python 3.7, try the command:

py -3.7

If you want the latest version of Python 2 you have installed, try the command:

py -2

If you see the following error, you do not have the launcher installed:

'py' is not recognized as an internal or external command,
operable program or batch file.

The command:

py --list

displays the currently installed version(s) of Python.

The -x.y argument is the short form of the -V:Company/Tag argument, which allows selecting a specific Python runtime, including those that may have come from somewhere other than python.org. Any runtime registered by following PEP 514 [https://peps.python.org/pep-0514/] will be discoverable. The --list command lists all available runtimes using the -V: format.

When using the -V: argument, specifying the Company will limit selection to runtimes from that provider, while specifying only the Tag will select from all providers. Note that omitting the slash implies a tag:

# Select any '3.*' tagged runtime
py -V:3

# Select any 'PythonCore' released runtime
py -V:PythonCore/

# Select PythonCore's latest Python 3 runtime
py -V:PythonCore/3

The short form of the argument (-3) only ever selects from core Python releases, and not other distributions. However, the longer form (-V:3) will select from any.

The Company is matched on the full string, case-insensitive. The Tag is matched on either the full string, or a prefix, provided the next character is a dot or a hyphen. This allows -V:3.1 to match 3.1-32, but not 3.10. Tags are sorted using numerical ordering (3.10 is newer than 3.1), but are compared using text (-V:3.01 does not match 3.1).

4.8.1.2. 가상 환경

Added in version 3.5.

런처가 명시적인 파이썬 버전 지정 없이 실행되고, 가상 환경(표준 라이브러리 venv 모듈이나 외부 virtualenv 도구로 생성된)이 활성화되었으면, 런처는 전역 인터프리터가 아닌 가상 환경의 인터프리터를 실행합니다. 전역 인터프리터를 실행하려면 가상 환경을 비활성화하거나, 전역 파이썬 버전을 명시적으로 지정하십시오.

4.8.1.3. 스크립트에서

테스트 파이썬 스크립트를 만들어 봅시다 - 다음 내용으로 hello.py라는 파일을 만듭니다.

#! python
import sys
sys.stdout.write("hello from Python %s\n" % (sys.version,))

From the directory in which hello.py lives, execute the command:

py hello.py

최신 파이썬 2.x 설치의 버전 번호가 인쇄됨을 알 수 있습니다. 이제 첫 번째 줄을 다음과 같이 변경합니다:

#! python3

Re-executing the command should now print the latest Python 3.x information. As with the above command-line examples, you can specify a more explicit version qualifier. Assuming you have Python 3.7 installed, try changing the first line to #! python3.7 and you should find the 3.7 version information printed.

대화 형 사용과 달리, 장식 없는 “python”은 설치된 파이썬 2.x의 최신 버전을 사용합니다. 이는 이전 버전과의 호환성과 유닉스와의 호환성을 위한 것입니다, 여기서 python 명령은 일반적으로 파이썬 2를 참조합니다.

4.8.1.4. 파일 연결에서

런처는 설치 시 파이썬 파일(즉 .py, .pyw, .pyc 파일)과 연결되어 있어야 합니다. 즉, 윈도우 탐색기에서 이러한 파일 중 하나를 더블 클릭하면 런처가 사용되므로, 위에서 설명한 것과 같은 기능을 사용하여 스크립트에서 사용해야 하는 버전을 지정할 수 있습니다.

이것의 주요 이점은 첫 번째 줄의 내용에 따라 단일 런처가 동시에 여러 파이썬 버전을 지원할 수 있다는 것입니다.

4.8.2. 셔뱅 줄

스크립트 파일의 첫 번째 줄이 #!로 시작하면 “셔뱅(shebang)”줄이라고 합니다. 리눅스와 기타 유닉스 류 운영 체제는 이러한 줄을 기본적으로 지원하며 스크립트 실행 방법을 나타내기 위해 이러한 시스템에서 일반적으로 사용됩니다. 이 런처를 사용하면 윈도우에서 파이썬 스크립트로 같은 기능을 사용할 수 있으며 위의 예제는 그 사용법을 보여줍니다.

파이썬 스크립트의 셔뱅 줄을 유닉스와 윈도우 간에 이식성 있도록 하기 위해, 이 런처는 사용할 인터프리터를 지정하는 여러 ‘가상’ 명령을 지원합니다. 지원되는 가상 명령은 다음과 같습니다:

/usr/bin/env

/usr/bin/python

/usr/local/bin/python

python

예를 들어, 스크립트의 첫 번째 줄이 다음과 같이 시작하면

#! /usr/bin/python

The default Python or an active virtual environment will be located and used. As many Python scripts written to work on Unix will already have this line, you should find these scripts can be used by the launcher without modification. If you are writing a new script on Windows which you hope will be useful on Unix, you should use one of the shebang lines starting with /usr.

Any of the above virtual commands can be suffixed with an explicit version (either just the major version, or the major and minor version). Furthermore the 32-bit version can be requested by adding “-32” after the minor version. I.e. /usr/bin/python3.7-32 will request usage of the 32-bit Python 3.7. If a virtual environment is active, the version will be ignored and the environment will be used.

Added in version 3.7: 파이썬 런처 3.7부터는 “-64” 접미사로 64비트 버전을 요청할 수 있습니다. 또한 부 버전 없이 주 버전과 아키텍처를 지정할 수 있습니다 (즉 /usr/bin/python3-64).

버전 3.11에서 변경: The “-64” suffix is deprecated, and now implies “any architecture that is not provably i386/32-bit”. To request a specific environment, use the new -V:TAG argument with the complete tag.

버전 3.13에서 변경: Virtual commands referencing python now prefer an active virtual environment rather than searching PATH. This handles cases where the shebang specifies /usr/bin/env python3 but python3.exe is not present in the active environment.

The /usr/bin/env form of shebang line has one further special property. Before looking for installed Python interpreters, this form will search the executable PATH for a Python executable matching the name provided as the first argument. This corresponds to the behaviour of the Unix env program, which performs a PATH search. If an executable matching the first argument after the env command cannot be found, but the argument starts with python, it will be handled as described for the other virtual commands. The environment variable PYLAUNCHER_NO_SEARCH_PATH may be set (to any value) to skip this search of PATH.

Shebang lines that do not match any of these patterns are looked up in the [commands] section of the launcher’s .INI file. This may be used to handle certain commands in a way that makes sense for your system. The name of the command must be a single argument (no spaces in the shebang executable), and the value substituted is the full path to the executable (additional arguments specified in the .INI will be quoted as part of the filename).

[commands]
/bin/xpython=C:\Program Files\XPython\python.exe

Any commands not found in the .INI file are treated as Windows executable paths that are absolute or relative to the directory containing the script file. This is a convenience for Windows-only scripts, such as those generated by an installer, since the behavior is not compatible with Unix-style shells. These paths may be quoted, and may include multiple arguments, after which the path to the script and any additional arguments will be appended.

4.8.3. 셔뱅 줄의 인자

셔뱅 줄은 또한 파이썬 인터프리터에 전달할 추가 옵션을 지정할 수 있습니다. 예를 들어, 다음과 같은 셔뱅 줄이 있으면:

#! /usr/bin/python -v

파이썬은 -v 옵션으로 시작됩니다

4.8.4. 사용자 정의

4.8.4.1. INI 파일을 통한 사용자 정의

Two .ini files will be searched by the launcher - py.ini in the current user’s application data directory (%LOCALAPPDATA% or $env:LocalAppData) and py.ini in the same directory as the launcher. The same .ini files are used for both the ‘console’ version of the launcher (i.e. py.exe) and for the ‘windows’ version (i.e. pyw.exe).

“응용 프로그램 디렉터리”에 지정된 사용자 정의가 실행 파일 옆에 있는 사용자 지정보다 우선하므로, 런처 옆에 있는 .ini 파일에 대한 쓰기 권한이 없는 사용자는 전역 .ini 파일에서 명령을 재정의할 수 있습니다.

4.8.4.2. 기본 파이썬 버전 사용자 정의

때에 따라, 버전 한정자를 명령에 포함하여 명령에서 사용할 파이썬 버전을 지정할 수 있습니다. 버전 한정자는 주 버전 번호로 시작하며 선택적으로 마침표(‘.’)와 부 버전 지정자가 올 수 있습니다. 또한 “-32”나 “-64”를 추가하여 32비트나 64비트 구현을 요청할지를 지정할 수 있습니다.

예를 들어, #!python의 셔뱅 줄에는 버전 한정자가 없는 반면, #!python3에는 주 버전 만 지정하는 버전 한정자가 있습니다.

명령에 버전 한정자가 없으면, 환경 변수 PY_PYTHON을 설정하여 기본 버전 한정자를 지정할 수 있습니다. 설정되지 않으면, 기본값은 “3”입니다. 변수는 “3”, “3.7”, “3.7-32” 또는 “3.7-64”와 같이 명령 줄에서 전달할 수 있는 모든 값을 지정할 수 있습니다. (“-64” 옵션은 파이썬 3.7 이상에 포함된 런처에서만 사용할 수 있음에 유의하십시오.)

부 버전 한정자가 없으면, 환경 변수 PY_PYTHON{major}(여기서 {major}는 위에서 결정된 현재 주 버전 한정자입니다)를 설정하여 전체 버전을 지정할 수 있습니다. 그러한 옵션이 없으면, 런처는 설치된 파이썬 버전을 열거하고 주 버전에 대해 발견된 최신 부 릴리스를 사용합니다. 이것은 보장되지는 않지만, 해당 제품군에서 가장 최근에 설치된 버전일 가능성이 높습니다.

같은 (major.minor) 파이썬 버전의 32비트와 64비트 구현이 모두 설치된 64비트 윈도우에서는 항상 64비트 버전이 선호됩니다. 이는 32비트와 64비트 런처 구현 모두에 해당합니다 - 32비트 런처는 가능하면 지정된 버전의 64비트 파이썬 설치를 실행하는 것을 선호합니다. 따라서 런처의 동작은 PC에 설치된 버전만 알고 설치 순서와 관계없이 (즉, 32비트나 64비트 버전의 파이썬과 해당 런처가 마지막에 설치되었는지 알지 못하고) 예측할 수 있습니다). 위에서 언급했듯이, 선택적 “-32”나 “-64” 접미사를 버전 지정자에 사용하여 이 동작을 변경할 수 있습니다.

예:

관련 옵션이 설정되지 않으면, python과 python2 명령은 설치된 최신 파이썬 2.x 버전을 사용하고 python3 명령은 설치된 최신 파이썬 3.x를 사용합니다.

The command python3.7 will not consult any options at all as the versions are fully specified.

PY_PYTHON=3이면, python과 python3 명령은 모두 최신 설치된 파이썬 3 버전을 사용합니다.

If PY_PYTHON=3.7-32, the command python will use the 32-bit implementation of 3.7 whereas the command python3 will use the latest installed Python (PY_PYTHON was not considered at all as a major version was specified.)

If PY_PYTHON=3 and PY_PYTHON3=3.7, the commands python and python3 will both use specifically 3.7

환경 변수 외에도, 런처에서 사용하는 .INI 파일에서 같은 설정을 구성할 수 있습니다. INI 파일의 섹션은 [defaults]라고 하며 키 이름은 선행 PY_ 접두어가 없는 환경 변수와 같습니다 (그리고 INI 파일의 키 이름은 대소 문자를 구분하지 않음에 유의하십시오.) 환경 변수의 내용은 INI 파일에 지정된 것을 재정의합니다.

예를 들면:

Setting PY_PYTHON=3.7 is equivalent to the INI file containing:

[defaults]
python=3.7

Setting PY_PYTHON=3 and PY_PYTHON3=3.7 is equivalent to the INI file containing:

[defaults]
python=3
python3=3.7

4.8.5. 진단

If an environment variable PYLAUNCHER_DEBUG is set (to any value), the launcher will print diagnostic information to stderr (i.e. to the console). While this information manages to be simultaneously verbose and terse, it should allow you to see what versions of Python were located, why a particular version was chosen and the exact command-line used to execute the target Python. It is primarily intended for testing and debugging.

4.8.6. Dry Run

If an environment variable PYLAUNCHER_DRYRUN is set (to any value), the launcher will output the command it would have run, but will not actually launch Python. This may be useful for tools that want to use the launcher to detect and then launch Python directly. Note that the command written to standard output is always encoded using UTF-8, and may not render correctly in the console.

4.8.7. Install on demand

If an environment variable PYLAUNCHER_ALLOW_INSTALL is set (to any value), and the requested Python version is not installed but is available on the Microsoft Store, the launcher will attempt to install it. This may require user interaction to complete, and you may need to run the command again.

An additional PYLAUNCHER_ALWAYS_INSTALL variable causes the launcher to always try to install Python, even if it is detected. This is mainly intended for testing (and should be used with PYLAUNCHER_DRYRUN).

4.8.8. Return codes

The following exit codes may be returned by the Python launcher. Unfortunately, there is no way to distinguish these from the exit code of Python itself.

The names of codes are as used in the sources, and are only for reference. There is no way to access or resolve them apart from reading this page. Entries are listed in alphabetical order of names.

이름

Value

설명

RC_BAD_VENV_CFG

107

A pyvenv.cfg was found but is corrupt.

RC_CREATE_PROCESS

101

Failed to launch Python.

RC_INSTALLING

111

An install was started, but the command will need to be re-run after it completes.

RC_INTERNAL_ERROR

109

Unexpected error. Please report a bug.

RC_NO_COMMANDLINE

108

Unable to obtain command line from the operating system.

RC_NO_PYTHON

103

Unable to locate the requested version.

RC_NO_VENV_CFG

106

A pyvenv.cfg was required but not found.

4.9. 모듈 찾기

These notes supplement the description at The initialization of the sys.path module search path with detailed Windows notes.

._pth 파일이 없을 때, 윈도우에서 sys.path를 채우는 방법은 다음과 같습니다:

시작에 현재 디렉터리에 해당하는 빈 항목이 추가됩니다.

환경 변수에 설명된 대로, 환경 변수 PYTHONPATH가 존재하면, 해당 항목이 다음에 추가됩니다. 윈도우에서, 이 변수의 경로는 드라이브 식별자(C:\ 등)에 사용되는 콜론과 구별하기 위해 세미콜론으로 구분되어야 합니다.

추가 “응용 프로그램 경로”는 HKEY_CURRENT_USER와 HKEY_LOCAL_MACHINE 하이브 모두의 아래에 \SOFTWARE\Python\PythonCore{version}\PythonPath의 하위 키로 레지스트리에 추가될 수 있습니다. 세미콜론으로 구분된 경로 문자열을 기본값으로 사용하는 하위 키는 각 경로가 sys.path에 추가되도록 합니다. (알려진 모든 설치 프로그램은 HKLM 만 사용하므로, HKCU는 일반적으로 비어 있음에 유의하십시오.)

환경 변수 PYTHONHOME이 설정되면, “파이썬 홈”으로 간주합니다. 그렇지 않으면, 메인 파이썬 실행 파일의 경로를 사용하여 “랜드마크 파일”(Lib\os.py나 pythonXY.zip)을 찾아 “파이썬 홈”을 추론합니다. 파이썬 홈이 발견되면, sys.path에 추가되는 관련 하위 디렉터리(Lib, plat-win 등)는 해당 폴더를 기반으로 합니다. 그렇지 않으면, 핵심 파이썬 경로가 레지스트리에 저장된 PythonPath에서 구성됩니다.

파이썬 홈을 찾을 수 없고, 환경에 PYTHONPATH가 지정되어 있지 않고, 레지스트리 항목을 찾을 수 없으면, 상대 항목의 기본 경로(예를 들어 .\Lib;.\plat-win 등)가 사용됩니다.

pyvenv.cfg 파일이 메인 실행 파일과 함께 또는 실행 파일보다 한 수준 위의 디렉터리에서 발견되면, 다음 변형이 적용됩니다:

home이 절대 경로이고 PYTHONHOME이 설정되지 않으면, 홈 위치를 추론할 때 메인 실행 파일에 대한 경로 대신 이 경로가 사용됩니다.

이 모든 것의 최종 결과는 다음과 같습니다:

python.exe 또는 기본 파이썬 디렉터리 (설치된 버전 또는 PCbuild 디렉터리에서 직접)에서 다른 .exe를 실행할 때 핵심 경로가 추론되고 레지스트리의 핵심 경로가 무시됩니다. 레지스트리의 다른 “응용 프로그램 경로”는 항상 읽습니다.

파이썬이 다른 .exe(다른 디렉터리, COM을 통한 내장, 등)에서 호스팅 될 때, “파이썬 홈”이 추론되지 않아서, 레지스트리의 핵심 경로가 사용됩니다. 레지스트리의 다른 “응용 프로그램 경로”는 항상 읽힙니다.

파이썬이 홈을 찾을 수 없고 레지스트리 값이 없으면 (고정된(frozen) .exe, 아주 이상한 설치 설정), 일부 기본 (하지만 상대) 경로를 얻게 됩니다.

파이썬을 응용 프로그램이나 배포에 번들로 포함하려는 사용자를 위해, 다음 조언은 다른 설치와의 충돌을 방지합니다:

포함할 디렉터리가 포함된 실행 파일과 함께 ._pth 파일을 포함합니다. 이것은 레지스트리와 환경 변수에 나열된 경로를 무시하고, import site가 나열되지 않는 한 site도 무시합니다.

If you are loading python3.dll or python37.dll in your own executable, explicitly set PyConfig.module_search_paths before Py_InitializeFromConfig().

응용 프로그램에서 python.exe를 시작하기 전에 PYTHONPATH를 지우거나 덮어쓰고 PYTHONHOME를 설정하십시오.

이전 제안을 사용할 수 없으면 (예를 들어, 사용자가 python.exe를 직접 실행할 수 있는 배포판이면), 랜드마크 파일(Lib\os.py)이 설치 디렉터리에 있도록 하십시오. (ZIP 파일 내에서는 감지되지 않지만, 대신 올바른 이름의 ZIP 파일은 감지됨에 유의하십시오.)

이렇게 하면 시스템 전체 설치의 파일이 응용 프로그램과 함께 번들로 제공되는 표준 라이브러리의 복사본보다 우선하지 않습니다. 그렇지 않으면, 사용자가 여러분의 응용 프로그램을 사용하는 데 문제가 발생할 수 있습니다. 다른 제안은 레지스트리의 비표준 경로와 사용자 site-packages에 여전히 취약할 수 있어서, 첫 번째 제안이 가장 좋음에 유의하십시오.

버전 3.6에서 변경: Add ._pth file support and removes applocal option from pyvenv.cfg.

버전 3.6에서 변경: Add pythonXX.zip as a potential landmark when directly adjacent to the executable.

버전 3.6부터 폐지됨: Modules specified in the registry under Modules (not PythonPath) may be imported by importlib.machinery.WindowsRegistryFinder. This finder is enabled on Windows in 3.6.0 and earlier, but may need to be explicitly added to sys.meta_path in the future.

4.10. 추가 모듈

파이썬이 모든 플랫폼 간에 이식성 있는 것을 목표로 하지만, 윈도우에만 고유한 기능이 있습니다. 이러한 기능을 사용하기 위한 표준 라이브러리와 외부에 있는 두 개의 모듈과 스니펫(snippets)이 존재합니다.

윈도우 특정 표준 모듈은 MS 윈도우 특정 서비스에 설명되어 있습니다.

4.10.1. PyWin32

The PyWin32 [https://pypi.org/project/PyWin32/] module by Mark Hammond is a collection of modules for advanced Windows-specific support. This includes utilities for:

Component Object Model [https://learn.microsoft.com/windows/win32/com/component-object-model--com--portal] (COM)

Win32 API 호출

레지스트리

이벤트 로그

Microsoft Foundation Classes [https://learn.microsoft.com/cpp/mfc/mfc-desktop-applications] (MFC) user interfaces

PythonWin [https://web.archive.org/web/20060524042422/https://www.python.org/windows/pythonwin/]은 PyWin32와 함께 제공되는 샘플 MFC 응용 프로그램입니다. 디버거가 내장된 내장할 수 있는 IDE입니다.

더 보기

Win32 How Do I…? [https://timgolden.me.uk/python/win32_how_do_i.html]

저자: Tim Golden

Python and COM [https://www.boddie.org.uk/python/COM.html]

저자: David와 Paul Boddie

4.10.2. cx_Freeze

cx_Freeze [https://cx-freeze.readthedocs.io/en/latest/] wraps Python scripts into executable Windows programs (*.exe files). When you have done this, you can distribute your application without requiring your users to install Python.

4.11. 윈도우에서 파이썬 컴파일하기

If you want to compile CPython yourself, first thing you should do is get the source [https://www.python.org/downloads/source/]. You can download either the latest release’s source or just grab a fresh checkout [https://devguide.python.org/setup/#get-the-source-code].

The source tree contains a build solution and project files for Microsoft Visual Studio, which is the compiler used to build the official Python releases. These files are in the PCbuild directory.

빌드 프로세스에 대한 일반 정보는 PCbuild/readme.txt를 확인하십시오.

확장 모듈에 대해서는, 윈도우에서 C와 C++ 확장 빌드하기를 참조하십시오.

4.12. 기타 플랫폼

파이썬의 지속적인 개발로 인해, 이전에 지원되던 일부 플랫폼은 더는 지원되지 않습니다 (사용자나 개발자 부족으로 인해). 지원되지 않는 모든 플랫폼에 대한 자세한 내용은 PEP 11 [https://peps.python.org/pep-0011/]을 확인하십시오.

Windows CE [https://pythonce.sourceforge.net/] is no longer supported [https://github.com/python/cpython/issues/71542] since Python 3 (if it ever was).

The Cygwin [https://cygwin.com/] installer offers to install the Python interpreter [https://cygwin.com/packages/summary/python3.html] as well

사전 컴파일된 설치 프로그램이 있는 플랫폼에 대한 자세한 정보는 Python for Windows [https://www.python.org/downloads/windows/]를 참조하십시오.

5. Using Python on macOS

This document aims to give an overview of macOS-specific behavior you should know about to get started with Python on Mac computers. Python on a Mac running macOS is very similar to Python on other Unix-derived platforms, but there are some differences in installation and some features.

There are various ways to obtain and install Python for macOS. Pre-built versions of the most recent versions of Python are available from a number of distributors. Much of this document describes use of the Pythons provided by the CPython release team for download from the python.org website [https://www.python.org/downloads/]. See Alternative Distributions for some other options.

5.1. Using Python for macOS from python.org

5.1.1. Installation steps

For current Python versions [https://www.python.org/downloads/] (other than those in security status), the release team produces a Python for macOS installer package for each new release. A list of available installers is available here [https://www.python.org/downloads/macos/]. We recommend using the most recent supported Python version where possible. Current installers provide a universal2 binary [https://en.wikipedia.org/wiki/Universal_binary] build of Python which runs natively on all Macs (Apple Silicon and Intel) that are supported by a wide range of macOS versions, currently typically from at least macOS 10.13 High Sierra on.

The downloaded file is a standard macOS installer package file (.pkg). File integrity information (checksum, size, sigstore signature, etc) for each file is included on the release download page. Installer packages and their contents are signed and notarized with Python Software Foundation Apple Developer ID certificates to meet macOS Gatekeeper requirements [https://support.apple.com/en-us/102445].

For a default installation, double-click on the downloaded installer package file. This should launch the standard macOS Installer app and display the first of several installer windows steps.

Clicking on the Continue button brings up the Read Me for this installer. Besides other important information, the Read Me documents which Python version is going to be installed and on what versions of macOS it is supported. You may need to scroll through to read the whole file. By default, this Read Me will also be installed in /Applications/Python 3.13/ and available to read anytime.

Clicking on Continue proceeds to display the license for Python and for other included software. You will then need to Agree to the license terms before proceeding to the next step. This license file will also be installed and available to be read later.

After the license terms are accepted, the next step is the Installation Type display. For most uses, the standard set of installation operations is appropriate.

By pressing the Customize button, you can choose to omit or select certain package components of the installer. Click on each package name to see a description of what it installs. To also install support for the optional experimental free-threaded feature, see Installing Free-threaded Binaries.

In either case, clicking Install will begin the install process by asking permission to install new software. A macOS user name with Administrator privilege is needed as the installed Python will be available to all users of the Mac.

When the installation is complete, the Summary window will appear.

Double-click on the Install Certificates.command icon or file in the /Applications/Python 3.13/ window to complete the installation.

This will open a temporary Terminal shell window that will use the new Python to download and install SSL root certificates for its use.

If Successfully installed certifi and update complete appears in the terminal window, the installation is complete. Close this terminal window and the installer window.

A default install will include:

A Python 3.13 folder in your Applications folder. In here you find IDLE, the development environment that is a standard part of official Python distributions; and Python Launcher, which handles double-clicking Python scripts from the macOS Finder [https://support.apple.com/en-us/HT201732].

A framework /Library/Frameworks/Python.framework, which includes the Python executable and libraries. The installer adds this location to your shell path. To uninstall Python, you can remove these three things. Symlinks to the Python executable are placed in /usr/local/bin/.

참고

Recent versions of macOS include a python3 command in /usr/bin/python3 that links to a usually older and incomplete version of Python provided by and for use by the Apple development tools, Xcode or the Command Line Tools for Xcode. You should never modify or attempt to delete this installation, as it is Apple-controlled and is used by Apple-provided or third-party software. If you choose to install a newer Python version from python.org, you will have two different but functional Python installations on your computer that can co-exist. The default installer options should ensure that its python3 will be used instead of the system python3.

5.1.2. 파이썬 스크립트를 실행하는 방법

There are two ways to invoke the Python interpreter. If you are familiar with using a Unix shell in a terminal window, you can invoke python3.13 or python3 optionally followed by one or more command line options (described in 명령 줄과 환경). The Python tutorial also has a useful section on using Python interactively from a shell.

You can also invoke the interpreter through an integrated development environment. IDLE is a basic editor and interpreter environment which is included with the standard distribution of Python. IDLE includes a Help menu that allows you to access Python documentation. If you are completely new to Python, you can read the tutorial introduction in that document.

There are many other editors and IDEs available, see 편집기와 IDE for more information.

To run a Python script file from the terminal window, you can invoke the interpreter with the name of the script file:

python3.13 myscript.py

To run your script from the Finder, you can either:

Drag it to Python Launcher.

Select Python Launcher as the default application to open your script (or any .py script) through the Finder Info window and double-click it. Python Launcher has various preferences to control how your script is launched. Option-dragging allows you to change these for one invocation, or use its Preferences menu to change things globally.

Be aware that running the script directly from the macOS Finder might produce different results than when running from a terminal window as the script will not be run in the usual shell environment including any setting of environment variables in shell profiles. And, as with any other script or program, be certain of what you are about to run.

5.2. Alternative Distributions

Besides the standard python.org for macOS installer, there are third-party distributions for macOS that may include additional functionality. Some popular distributions and their key features:

ActivePython [https://www.activestate.com/products/python/]

Installer with multi-platform compatibility, documentation

Anaconda [https://www.anaconda.com/download/]

Popular scientific modules (such as numpy, scipy, and pandas) and the conda package manager.

Homebrew [https://brew.sh]

Package manager for macOS including multiple versions of Python and many third-party Python-based packages (including numpy, scipy, and pandas).

MacPorts [https://www.macports.org]

Another package manager for macOS including multiple versions of Python and many third-party Python-based packages. May include pre-built versions of Python and many packages for older versions of macOS.

Note that distributions might not include the latest versions of Python or other libraries, and are not maintained or supported by the core Python team.

5.3. 추가 파이썬 패키지 설치하기

Refer to the Python Packaging User Guide [https://packaging.python.org/en/latest/tutorials/installing-packages/] for more information.

5.4. GUI Programming

Mac에서 파이썬으로 GUI 응용 프로그램을 작성하기 위한 몇 가지 옵션이 있습니다.

The standard Python GUI toolkit is tkinter, based on the cross-platform Tk toolkit (https://www.tcl.tk). A macOS-native version of Tk is included with the installer.

PyObjC is a Python binding to Apple’s Objective-C/Cocoa framework. Information on PyObjC is available from pyobjc [https://pypi.org/project/pyobjc/].

A number of alternative macOS GUI toolkits are available including:

PySide [https://www.qt.io/qt-for-python]: Official Python bindings to the Qt GUI toolkit [https://wiki.qt.io/Qt_for_Python].

PyQt [https://riverbankcomputing.com/software/pyqt/]: Alternative Python bindings to Qt.

Kivy [https://kivy.org]: A cross-platform GUI toolkit that supports desktop and mobile platforms.

Toga [https://toga.readthedocs.io]: Part of the BeeWare Project [https://beeware.org]; supports desktop, mobile, web and console apps.

wxPython [https://wxpython.org]: A cross-platform toolkit that supports desktop operating systems.

5.5. Advanced Topics

5.5.1. Installing Free-threaded Binaries

Added in version 3.13: (Experimental)

참고

Everything described in this section is considered experimental, and should be expected to change in future releases.

The python.org Python for macOS installer package can optionally install an additional build of Python 3.13 that supports PEP 703 [https://peps.python.org/pep-0703/], the experimental free-threading feature (running with the global interpreter lock disabled). Check the release page on python.org for possible updated information.

Because this feature is still considered experimental, the support for it is not installed by default. It is packaged as a separate install option, available by clicking the Customize button on the Installation Type step of the installer as described above.

If the box next to the Free-threaded Python package name is checked, a separate PythonT.framework will also be installed alongside the normal Python.framework in /Library/Frameworks. This configuration allows a free-threaded Python 3.13 build to co-exist on your system with a traditional (GIL only) Python 3.13 build with minimal risk while installing or testing. This installation layout is itself experimental and is subject to change in future releases.

Known cautions and limitations:

The UNIX command-line tools package, which is selected by default, will install links in /usr/local/bin for python3.13t, the free-threaded interpreter, and python3.13t-config, a configuration utility which may be useful for package builders. Since /usr/local/bin is typically included in your shell PATH, in most cases no changes to your PATH environment variables should be needed to use python3.13t.

For this release, the Shell profile updater package and the Update Shell Profile.command in /Applications/Python 3.13/ do not support the free-threaded package.

The free-threaded build and the traditional build have separate search paths and separate site-packages directories so, by default, if you need a package available in both builds, it may need to be installed in both. The free-threaded package will install a separate instance of pip for use with python3.13t.

To install a package using pip without a venv:

python3.13t -m pip install <package_name>

When working with multiple Python environments, it is usually safest and easiest to create and use virtual environments. This can avoid possible command name conflicts and confusion about which Python is in use:

python3.13t -m venv <venv_name>

then activate.

To run a free-threaded version of IDLE:

python3.13t -m idlelib

The interpreters in both builds respond to the same PYTHON environment variables which may have unexpected results, for example, if you have PYTHONPATH set in a shell profile. If necessary, there are command line options like -E to ignore these environment variables.

The free-threaded build links to the third-party shared libraries, such as OpenSSL and Tk, installed in the traditional framework. This means that both builds also share one set of trust certificates as installed by the Install Certificates.command script, thus it only needs to be run once.

If you cannot depend on the link in /usr/local/bin pointing to the python.org free-threaded python3.13t (for example, if you want to install your own version there or some other distribution does), you can explicitly set your shell PATH environment variable to include the PythonT framework bin directory:

export PATH="/Library/Frameworks/PythonT.framework/Versions/3.13/bin":"$PATH"

The traditional framework installation by default does something similar, except for Python.framework. Be aware that having both framework bin directories in PATH can lead to confusion if there are duplicate names like python3.13 in both; which one is actually used depends on the order they appear in PATH. The which python3.x or which python3.xt commands can show which path is being used. Using virtual environments can help avoid such ambiguities. Another option might be to create a shell alias to the desired interpreter, like:

alias py3.13="/Library/Frameworks/Python.framework/Versions/3.13/bin/python3.13"
alias py3.13t="/Library/Frameworks/PythonT.framework/Versions/3.13/bin/python3.13t"

5.5.2. Installing using the command line

If you want to use automation to install the python.org installer package (rather than by using the familiar macOS Installer GUI app), the macOS command line installer utility lets you select non-default options, too. If you are not familiar with installer, it can be somewhat cryptic (see man installer for more information). As an example, the following shell snippet shows one way to do it, using the 3.13.0b2 release and selecting the free-threaded interpreter option:

RELEASE="python-3.13.0b2-macos11.pkg"

# download installer pkg
curl -O https://www.python.org/ftp/python/3.13.0/${RELEASE}

# create installer choicechanges to customize the install:
#    enable the PythonTFramework-3.13 package
#    while accepting the other defaults (install all other packages)
cat > ./choicechanges.plist <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
        <dict>
                <key>attributeSetting</key>
                <integer>1</integer>
                <key>choiceAttribute</key>
                <string>selected</string>
                <key>choiceIdentifier</key>
                <string>org.python.Python.PythonTFramework-3.13</string>
        </dict>
</array>
</plist>
EOF

sudo installer -pkg ./${RELEASE} -applyChoiceChangesXML ./choicechanges.plist -target /

You can then test that both installer builds are now available with something like:

$ # test that the free-threaded interpreter was installed if the Unix Command Tools package was enabled
$ /usr/local/bin/python3.13t -VV
Python 3.13.0b2 experimental free-threading build (v3.13.0b2:3a83b172af, Jun  5 2024, 12:57:31) [Clang 15.0.0 (clang-1500.3.9.4)]
$ #    and the traditional interpreter
$ /usr/local/bin/python3.13 -VV
Python 3.13.0b2 (v3.13.0b2:3a83b172af, Jun  5 2024, 12:50:24) [Clang 15.0.0 (clang-1500.3.9.4)]
$ # test that they are also available without the prefix if /usr/local/bin is on $PATH
$ python3.13t -VV
Python 3.13.0b2 experimental free-threading build (v3.13.0b2:3a83b172af, Jun  5 2024, 12:57:31) [Clang 15.0.0 (clang-1500.3.9.4)]
$ python3.13 -VV
Python 3.13.0b2 (v3.13.0b2:3a83b172af, Jun  5 2024, 12:50:24) [Clang 15.0.0 (clang-1500.3.9.4)]

참고

Current python.org installers only install to fixed locations like /Library/Frameworks/, /Applications, and /usr/local/bin. You cannot use the installer -domain option to install to other locations.

5.5.3. Distributing Python Applications

A range of tools exist for converting your Python code into a standalone distributable application:

py2app [https://pypi.org/project/py2app/]: Supports creating macOS .app bundles from a Python project.

Briefcase [https://briefcase.readthedocs.io]: Part of the BeeWare Project [https://beeware.org]; a cross-platform packaging tool that supports creation of .app bundles on macOS, as well as managing signing and notarization.

PyInstaller [https://pyinstaller.org/]: A cross-platform packaging tool that creates a single file or folder as a distributable artifact.

5.5.4. App Store Compliance

Apps submitted for distribution through the macOS App Store must pass Apple’s app review process. This process includes a set of automated validation rules that inspect the submitted application bundle for problematic code.

The Python standard library contains some code that is known to violate these automated rules. While these violations appear to be false positives, Apple’s review rules cannot be challenged. Therefore, it is necessary to modify the Python standard library for an app to pass App Store review.

The Python source tree contains a patch file [https://github.com/python/cpython/tree/main/Mac/Resources/app-store-compliance.patch] that will remove all code that is known to cause issues with the App Store review process. This patch is applied automatically when CPython is configured with the --with-app-store-compliance option.

This patch is not normally required to use CPython on a Mac; nor is it required if you are distributing an app outside the macOS App Store. It is only required if you are using the macOS App Store as a distribution channel.

5.6. 기타 자원

The python.org Help page [https://www.python.org/about/help/] has links to many useful resources. The Pythonmac-SIG mailing list [https://www.python.org/community/sigs/current/pythonmac-sig/] is another support resource specifically for Python users and developers on the Mac.

6. Using Python on Android

Python on Android is unlike Python on desktop platforms. On a desktop platform, Python is generally installed as a system resource that can be used by any user of that computer. Users then interact with Python by running a python executable and entering commands at an interactive prompt, or by running a Python script.

On Android, there is no concept of installing as a system resource. The only unit of software distribution is an “app”. There is also no console where you could run a python executable, or interact with a Python REPL.

As a result, the only way you can use Python on Android is in embedded mode – that is, by writing a native Android application, embedding a Python interpreter using libpython, and invoking Python code using the Python embedding API. The full Python interpreter, the standard library, and all your Python code is then packaged into your app for its own private use.

The Python standard library has some notable omissions and restrictions on Android. See the API availability guide for details.

6.1. Adding Python to an Android app

These instructions are only needed if you’re planning to compile Python for Android yourself. Most users should not need to do this. Instead, use one of the following tools, which will provide a much easier experience:

Briefcase [https://briefcase.readthedocs.io], from the BeeWare project

Buildozer [https://buildozer.readthedocs.io], from the Kivy project

Chaquopy [https://chaquo.com/chaquopy]

pyqtdeploy [https://www.riverbankcomputing.com/static/Docs/pyqtdeploy/]

Termux [https://termux.dev/en/]

If you’re sure you want to do all of this manually, read on. You can use the testbed app [https://github.com/python/cpython/tree/main/Android/testbed] as a guide; each step below contains a link to the relevant file.

Build Python by following the instructions in Android/README.md [https://github.com/python/cpython/tree/main/Android/README.md].

Add code to your build.gradle [https://github.com/python/cpython/tree/main/Android/testbed/app/build.gradle.kts] file to copy the following items into your project. All except your own Python code can be copied from cross-build/HOST/prefix/lib:

In your JNI libraries:

libpython*.*.so

lib*_python.so (external libraries such as OpenSSL)

In your assets:

python*.* (the Python standard library)

python*.*/site-packages (your own Python code)

Add code to your app to extract the assets to the filesystem [https://github.com/python/cpython/tree/main/Android/testbed/app/src/main/java/org/python/testbed/MainActivity.kt].

Add code to your app to start Python in embedded mode [https://github.com/python/cpython/tree/main/Android/testbed/app/src/main/c/main_activity.c]. This will need to be C code called via JNI.

7. Using Python on iOS

Authors:

Russell Keith-Magee (2024-03)

Python on iOS is unlike Python on desktop platforms. On a desktop platform, Python is generally installed as a system resource that can be used by any user of that computer. Users then interact with Python by running a python executable and entering commands at an interactive prompt, or by running a Python script.

On iOS, there is no concept of installing as a system resource. The only unit of software distribution is an “app”. There is also no console where you could run a python executable, or interact with a Python REPL.

As a result, the only way you can use Python on iOS is in embedded mode - that is, by writing a native iOS application, and embedding a Python interpreter using libPython, and invoking Python code using the Python embedding API. The full Python interpreter, the standard library, and all your Python code is then packaged as a standalone bundle that can be distributed via the iOS App Store.

If you’re looking to experiment for the first time with writing an iOS app in Python, projects such as BeeWare [https://beeware.org] and Kivy [https://kivy.org] will provide a much more approachable user experience. These projects manage the complexities associated with getting an iOS project running, so you only need to deal with the Python code itself.

7.1. Python at runtime on iOS

7.1.1. iOS version compatibility

The minimum supported iOS version is specified at compile time, using the --host option to configure. By default, when compiled for iOS, Python will be compiled with a minimum supported iOS version of 13.0. To use a different minimum iOS version, provide the version number as part of the --host argument - for example, --host=arm64-apple-ios15.4-simulator would compile an ARM64 simulator build with a deployment target of 15.4.

7.1.2. Platform identification

When executing on iOS, sys.platform will report as ios. This value will be returned on an iPhone or iPad, regardless of whether the app is running on the simulator or a physical device.

Information about the specific runtime environment, including the iOS version, device model, and whether the device is a simulator, can be obtained using platform.ios_ver(). platform.system() will report iOS or iPadOS, depending on the device.

os.uname() reports kernel-level details; it will report a name of Darwin.

7.1.3. Standard library availability

The Python standard library has some notable omissions and restrictions on iOS. See the API availability guide for iOS for details.

7.1.4. Binary extension modules

One notable difference about iOS as a platform is that App Store distribution imposes hard requirements on the packaging of an application. One of these requirements governs how binary extension modules are distributed.

The iOS App Store requires that all binary modules in an iOS app must be dynamic libraries, contained in a framework with appropriate metadata, stored in the Frameworks folder of the packaged app. There can be only a single binary per framework, and there can be no executable binary material outside the Frameworks folder.

This conflicts with the usual Python approach for distributing binaries, which allows a binary extension module to be loaded from any location on sys.path. To ensure compliance with App Store policies, an iOS project must post-process any Python packages, converting .so binary modules into individual standalone frameworks with appropriate metadata and signing. For details on how to perform this post-processing, see the guide for adding Python to your project.

To help Python discover binaries in their new location, the original .so file on sys.path is replaced with a .fwork file. This file is a text file containing the location of the framework binary, relative to the app bundle. To allow the framework to resolve back to the original location, the framework must contain a .origin file that contains the location of the .fwork file, relative to the app bundle.

For example, consider the case of an import from foo.bar import _whiz, where _whiz is implemented with the binary module sources/foo/bar/_whiz.abi3.so, with sources being the location registered on sys.path, relative to the application bundle. This module must be distributed as Frameworks/foo.bar._whiz.framework/foo.bar._whiz (creating the framework name from the full import path of the module), with an Info.plist file in the .framework directory identifying the binary as a framework. The foo.bar._whiz module would be represented in the original location with a sources/foo/bar/_whiz.abi3.fwork marker file, containing the path Frameworks/foo.bar._whiz/foo.bar._whiz. The framework would also contain Frameworks/foo.bar._whiz.framework/foo.bar._whiz.origin, containing the path to the .fwork file.

When running on iOS, the Python interpreter will install an AppleFrameworkLoader that is able to read and import .fwork files. Once imported, the __file__ attribute of the binary module will report as the location of the .fwork file. However, the ModuleSpec for the loaded module will report the origin as the location of the binary in the framework folder.

7.1.5. Compiler stub binaries

Xcode doesn’t expose explicit compilers for iOS; instead, it uses an xcrun script that resolves to a full compiler path (e.g., xcrun --sdk iphoneos clang to get the clang for an iPhone device). However, using this script poses two problems:

The output of xcrun includes paths that are machine specific, resulting in a sysconfig module that cannot be shared between users; and

It results in CC/CPP/LD/AR definitions that include spaces. There is a lot of C ecosystem tooling that assumes that you can split a command line at the first space to get the path to the compiler executable; this isn’t the case when using xcrun.

To avoid these problems, Python provided stubs for these tools. These stubs are shell script wrappers around the underingly xcrun tools, distributed in a bin folder distributed alongside the compiled iOS framework. These scripts are relocatable, and will always resolve to the appropriate local system paths. By including these scripts in the bin folder that accompanies a framework, the contents of the sysconfig module becomes useful for end-users to compile their own modules. When compiling third-party Python modules for iOS, you should ensure these stub binaries are on your path.

7.2. Installing Python on iOS

7.2.1. Tools for building iOS apps

Building for iOS requires the use of Apple’s Xcode tooling. It is strongly recommended that you use the most recent stable release of Xcode. This will require the use of the most (or second-most) recently released macOS version, as Apple does not maintain Xcode for older macOS versions. The Xcode Command Line Tools are not sufficient for iOS development; you need a full Xcode install.

If you want to run your code on the iOS simulator, you’ll also need to install an iOS Simulator Platform. You should be prompted to select an iOS Simulator Platform when you first run Xcode. Alternatively, you can add an iOS Simulator Platform by selecting from the Platforms tab of the Xcode Settings panel.

7.2.2. Adding Python to an iOS project

Python can be added to any iOS project, using either Swift or Objective C. The following examples will use Objective C; if you are using Swift, you may find a library like PythonKit [https://github.com/pvieito/PythonKit] to be helpful.

To add Python to an iOS Xcode project:

Build or obtain a Python XCFramework. See the instructions in iOS/README.rst [https://github.com/python/cpython/tree/main/iOS/README.rst] (in the CPython source distribution) for details on how to build a Python XCFramework. At a minimum, you will need a build that supports arm64-apple-ios, plus one of either arm64-apple-ios-simulator or x86_64-apple-ios-simulator.

Drag the XCframework into your iOS project. In the following instructions, we’ll assume you’ve dropped the XCframework into the root of your project; however, you can use any other location that you want by adjusting paths as needed.

Drag the iOS/Resources/dylib-Info-template.plist file into your project, and ensure it is associated with the app target.

Add your application code as a folder in your Xcode project. In the following instructions, we’ll assume that your user code is in a folder named app in the root of your project; you can use any other location by adjusting paths as needed. Ensure that this folder is associated with your app target.

Select the app target by selecting the root node of your Xcode project, then the target name in the sidebar that appears.

In the “General” settings, under “Frameworks, Libraries and Embedded Content”, add Python.xcframework, with “Embed & Sign” selected.

In the “Build Settings” tab, modify the following:

Build Options

User Script Sandboxing: No

Enable Testability: Yes

Search Paths

Framework Search Paths: $(PROJECT_DIR)

Header Search Paths: "$(BUILT_PRODUCTS_DIR)/Python.framework/Headers"

Apple Clang - Warnings - All languages

Quoted Include In Framework Header: No

Add a build step that copies the Python standard library into your app. In the “Build Phases” tab, add a new “Run Script” build step before the “Embed Frameworks” step, but after the “Copy Bundle Resources” step. Name the step “Install Target Specific Python Standard Library”, disable the “Based on dependency analysis” checkbox, and set the script content to:

set -e

mkdir -p "$CODESIGNING_FOLDER_PATH/python/lib"
if [ "$EFFECTIVE_PLATFORM_NAME" = "-iphonesimulator" ]; then
    echo "Installing Python modules for iOS Simulator"
    rsync -au --delete "$PROJECT_DIR/Python.xcframework/ios-arm64_x86_64-simulator/lib/" "$CODESIGNING_FOLDER_PATH/python/lib/"
else
    echo "Installing Python modules for iOS Device"
    rsync -au --delete "$PROJECT_DIR/Python.xcframework/ios-arm64/lib/" "$CODESIGNING_FOLDER_PATH/python/lib/"
fi

Note that the name of the simulator “slice” in the XCframework may be different, depending the CPU architectures your XCFramework supports.

Add a second build step that processes the binary extension modules in the standard library into “Framework” format. Add a “Run Script” build step directly after the one you added in step 8, named “Prepare Python Binary Modules”. It should also have “Based on dependency analysis” unchecked, with the following script content:

set -e

install_dylib () {
    INSTALL_BASE=$1
    FULL_EXT=$2

    # The name of the extension file
    EXT=$(basename "$FULL_EXT")
    # The location of the extension file, relative to the bundle
    RELATIVE_EXT=${FULL_EXT#$CODESIGNING_FOLDER_PATH/}
    # The path to the extension file, relative to the install base
    PYTHON_EXT=${RELATIVE_EXT/$INSTALL_BASE/}
    # The full dotted name of the extension module, constructed from the file path.
    FULL_MODULE_NAME=$(echo $PYTHON_EXT | cut -d "." -f 1 | tr "/" ".");
    # A bundle identifier; not actually used, but required by Xcode framework packaging
    FRAMEWORK_BUNDLE_ID=$(echo $PRODUCT_BUNDLE_IDENTIFIER.$FULL_MODULE_NAME | tr "_" "-")
    # The name of the framework folder.
    FRAMEWORK_FOLDER="Frameworks/$FULL_MODULE_NAME.framework"

    # If the framework folder doesn't exist, create it.
    if [ ! -d "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER" ]; then
        echo "Creating framework for $RELATIVE_EXT"
        mkdir -p "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER"
        cp "$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
        plutil -replace CFBundleExecutable -string "$FULL_MODULE_NAME" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
        plutil -replace CFBundleIdentifier -string "$FRAMEWORK_BUNDLE_ID" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
    fi

    echo "Installing binary for $FRAMEWORK_FOLDER/$FULL_MODULE_NAME"
    mv "$FULL_EXT" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME"
    # Create a placeholder .fwork file where the .so was
    echo "$FRAMEWORK_FOLDER/$FULL_MODULE_NAME" > ${FULL_EXT%.so}.fwork
    # Create a back reference to the .so file location in the framework
    echo "${RELATIVE_EXT%.so}.fwork" > "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME.origin"
 }

 PYTHON_VER=$(ls -1 "$CODESIGNING_FOLDER_PATH/python/lib")
 echo "Install Python $PYTHON_VER standard library extension modules..."
 find "$CODESIGNING_FOLDER_PATH/python/lib/$PYTHON_VER/lib-dynload" -name "*.so" | while read FULL_EXT; do
    install_dylib python/lib/$PYTHON_VER/lib-dynload/ "$FULL_EXT"
 done

 # Clean up dylib template
 rm -f "$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist"

 echo "Signing frameworks as $EXPANDED_CODE_SIGN_IDENTITY_NAME ($EXPANDED_CODE_SIGN_IDENTITY)..."
 find "$CODESIGNING_FOLDER_PATH/Frameworks" -name "*.framework" -exec /usr/bin/codesign --force --sign "$EXPANDED_CODE_SIGN_IDENTITY" ${OTHER_CODE_SIGN_FLAGS:-} -o runtime --timestamp=none --preserve-metadata=identifier,entitlements,flags --generate-entitlement-der "{}" \;

Add Objective C code to initialize and use a Python interpreter in embedded mode. You should ensure that:

UTF-8 mode is enabled;

Buffered stdio is disabled;

Writing bytecode is disabled;

Signal handlers are enabled;

PYTHONHOME for the interpreter is configured to point at the python subfolder of your app’s bundle; and

The PYTHONPATH for the interpreter includes:

the python/lib/python3.X subfolder of your app’s bundle,

the python/lib/python3.X/lib-dynload subfolder of your app’s bundle, and

the app subfolder of your app’s bundle

Your app’s bundle location can be determined using [[NSBundle mainBundle] resourcePath].

Steps 8, 9 and 10 of these instructions assume that you have a single folder of pure Python application code, named app. If you have third-party binary modules in your app, some additional steps will be required:

You need to ensure that any folders containing third-party binaries are either associated with the app target, or copied in as part of step 8. Step 8 should also purge any binaries that are not appropriate for the platform a specific build is targeting (i.e., delete any device binaries if you’re building an app targeting the simulator).

Any folders that contain third-party binaries must be processed into framework form by step 9. The invocation of install_dylib that processes the lib-dynload folder can be copied and adapted for this purpose.

If you’re using a separate folder for third-party packages, ensure that folder is included as part of the PYTHONPATH configuration in step 10.

7.3. App Store Compliance

The only mechanism for distributing apps to third-party iOS devices is to submit the app to the iOS App Store; apps submitted for distribution must pass Apple’s app review process. This process includes a set of automated validation rules that inspect the submitted application bundle for problematic code.

The Python standard library contains some code that is known to violate these automated rules. While these violations appear to be false positives, Apple’s review rules cannot be challenged; so, it is necessary to modify the Python standard library for an app to pass App Store review.

The Python source tree contains a patch file [https://github.com/python/cpython/tree/main/Mac/Resources/app-store-compliance.patch] that will remove all code that is known to cause issues with the App Store review process. This patch is applied automatically when building for iOS.

8. 편집기와 IDE

파이썬 프로그래밍 언어를 지원하는 여러 IDE가 있습니다. 많은 편집기와 IDE는 구문 강조, 디버깅 도구 및 PEP 8 [https://peps.python.org/pep-0008/] 검사를 제공합니다.

포괄적인 목록을 보려면 Python Editors [https://wiki.python.org/moin/PythonEditors]와 Integrated Development Environments [https://wiki.python.org/moin/IntegratedDevelopmentEnvironments]로 이동하십시오.

파이썬 언어 레퍼런스

이 참조 설명서는 언어의 문법과 “중심 개념들(core semantics)”을 설명합니다. 딱딱하더라도 정확하고 완전해지려고 합니다. 중심에서 벗어난 내장형, 내장 함수, 모듈들의 개념들은 파이썬 표준 라이브러리 에 기술되어 있습니다. 언어에 대한 비형식적인 소개는 파이썬 자습서 에서 제공됩니다. C와 C++ 프로그래머를 위해서는 두 개의 설명서가 따로 제공됩니다: 파이썬 인터프리터 확장 및 내장 는 파이썬 확장 모듈을 작성하는 방법에 대한 큰 그림을 설명하고, 파이썬/C API 레퍼런스 설명서 은 C/C++ 프로그래머에게 제공되는 인터페이스들을 상세하게 기술합니다.

1. 개요

1.1. 대안 구현들

1.2. 표기법

2. 어휘 분석

2.1. 줄 구조(Line structure)

2.2. 다른 토큰들

2.3. 식별자와 키워드

2.4. 리터럴

2.5. 연산자

2.6. 구분자

3. 데이터 모델

3.1. 객체, 값, 형

3.2. 표준형 계층

3.3. 특수 메서드 이름들

3.4. 코루틴(Coroutines)

4. 실행 모델

4.1. 프로그램의 구조

4.2. 이름과 연결(binding)

4.3. 예외

5. 임포트 시스템

5.1. importlib

5.2. 패키지(package)

5.3. 검색

5.4. 로딩(loading)

5.5. 경로 기반 파인더

5.6. 표준 임포트 시스템 교체하기

5.7. 패키지 상대 임포트

5.8. __main__ 에 대한 특별한 고려

5.9. 참고문헌

6. 표현식

6.1. 산술 변환

6.2. 아톰 (Atoms)

6.3. 프라이머리

6.4. 어웨이트 표현식

6.5. 거듭제곱 연산자

6.6. 일 항 산술과 비트 연산

6.7. 이항 산술 연산

6.8. 시프트 연산

6.9. 이항 비트 연산

6.10. 비교

6.11. 논리 연산(Boolean operations)

6.12. 대입 표현식

6.13. 조건 표현식(Conditional expressions)

6.14. 람다(Lambdas)

6.15. 표현식 목록(Expression lists)

6.16. 값을 구하는 순서

6.17. 연산자 우선순위

7. 단순문(Simple statements)

7.1. 표현식 문

7.2. 대입문

7.3. assert 문

7.4. pass 문

7.5. del 문

7.6. return 문

7.7. yield 문

7.8. raise 문

7.9. break 문

7.10. continue 문

7.11. 임포트(import) 문

7.12. global 문

7.13. nonlocal 문

7.14. The type statement

8. 복합문(Compound statements)

8.1. if 문

8.2. while 문

8.3. for 문

8.4. try 문

8.5. with 문

8.6. The match statement

8.7. 함수 정의

8.8. 클래스 정의

8.9. 코루틴

8.10. Type parameter lists

8.11. Annotations

9. 최상위 요소들

9.1. 완전한 파이썬 프로그램

9.2. 파일 입력

9.3. 대화형 입력

9.4. 표현식 입력

10. 전체 문법 규격

1. 개요

이 레퍼런스 설명서는 파이썬 프로그래밍 언어를 설명합니다. 자습서를 목표로 하고 있지 않습니다.

가능한 한 정확하려고 노력하고 있지만, 문법과 어휘 분석 이외의 모든 것에는 형식 규격보다는 자연어를 사용합니다. 이 선택이 평균적인 독자들이 문서를 좀 더 잘 이해하도록 만들지만, 동시에 모호해질 가능성 역시 만듭니다. 결과적으로, 만약 여러분이 화성에서 왔고 이 문서만으로 파이썬을 다시 구현하려고 하면, 아마도 여러 가지를 짐작해야 할 것이고 결국 많이 다른 언어를 만드는 것으로 끝날 것입니다. 반면에, 여러분이 파이썬을 사용하고 있고 언어의 특정 영역에 대한 정확한 규칙에 대해 궁금해하고 있다면 거의 확실히 이곳에서 답을 찾을 수 있습니다. 좀 더 형식화된 정의를 보고 싶다면, 아마도 여러분의 시간을 기부하는 편이 좋습니다 — 그렇지 않으면 클로닝 기계를 발명하거나 :-).

참조 문서에 너무 많은 구현 세부 사항을 넣는 것은 위험합니다. 구현은 변경될 것이고 같은 언어의 다른 구현도 좀 다른 방식으로 동작할 수 있습니다. 반면에 (대안 구현이 점차 지지도를 높여가고 있기는 하지만) CPython 은 가장 널리 사용되는 파이썬 구현이고, 그것의 특별한 경우 들은 때로 언급할 가치가 있습니다. 구현이 추가의 제약을 내포하고 있는 경우는 특히 그렇습니다. 그래서, 텍스트 중간중간 짧은 “구현 노트” 가 튀어나오는 것을 보게 될 것입니다.

모든 파이썬 구현에는 많은 내장 표준 모듈들이 따라옵니다. 이것들은 파이썬 표준 라이브러리 에 기술되어 있습니다. 언어 정의에 주목할 만한 방식으로 관계될 경우 몇몇 내장 모듈들은 따로 언급됩니다.

1.1. 대안 구현들

눈에 띄게 널리 사용되는 파이썬 구현이 존재하기는 하지만, 특정한 관심사를 가진 대상들에게 호소력을 가진 여러 대안 구현들이 존재합니다.

알려진 구현들은:

CPython

원조이기도 하고 가장 잘 관리되고 있는 C로 작성된 파이썬 구현입니다. 언어의 새로운 기능은 보통 여기에서 처음 등장합니다.

Jython

Python implemented in Java. This implementation can be used as a scripting language for Java applications, or can be used to create applications using the Java class libraries. It is also often used to create tests for Java libraries. More information can be found at the Jython website [https://www.jython.org/].

Python for .NET

이 구현은 실제로는 CPython 구현을 사용하지만, 매니지드(managed) .NET 응용 프로그램이고 .NET 라이브러리를 제공합니다. Bryan Lloyd가 만들었습니다다. 더 자세한 정보는 Python for .NET 홈페이지 [https://pythonnet.github.io/] 에서 제공됩니다.

IronPython

An alternate Python for .NET. Unlike Python.NET, this is a complete Python implementation that generates IL, and compiles Python code directly to .NET assemblies. It was created by Jim Hugunin, the original creator of Jython. For more information, see the IronPython website [https://ironpython.net/].

PyPy

An implementation of Python written completely in Python. It supports several advanced features not found in other implementations like stackless support and a Just in Time compiler. One of the goals of the project is to encourage experimentation with the language itself by making it easier to modify the interpreter (since it is written in Python). Additional information is available on the PyPy project’s home page [https://pypy.org/].

각 구현은 이 설명서에서 설명되는 언어와 조금씩 각기 다른 방법으로 벗어나거나, 표준 파이썬 문서에서 다루는 범위 밖의 특별한 정보들을 소개합니다. 여러분이 사용 중인 구현에 대해 어떤 것을 더 알아야 하는지 판단하기 위해서는 구현 별로 제공되는 문서를 참조할 필요가 있습니다.

1.2. 표기법

The descriptions of lexical analysis and syntax use a modified Backus–Naur form (BNF) [https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form] grammar notation. This uses the following style of definition:

name      ::=  lc_letter (lc_letter | "_")*
lc_letter ::=  "a"..."z"

첫 줄은 name 이 lc_letter 로 시작하고, 없거나 하나 이상의 lc_letter 나 밑줄이 뒤따르는 형태로 구성된다고 말합니다. 한편 lc_letter 는 'a' 와 'z' 사이의 문자 하나입니다. (사실 이 규칙은 이 문서에서 어휘와 문법 규칙에서 정의되는 이름들에 대한 규칙입니다.)

개별 규칙은 이름 (위 규칙에 등장하는 name)과 ::= 로 시작합니다. 세로막대(|)는 대안들을 분리하는 데 사용됩니다; 이 표기법에서 우선순위가 가장 낮은 연산자입니다. 별표(*)는 앞에 나오는 항목이 생략되거나 한 번 이상 반복될 수 있다는 의미입니다; 비슷하게, 더하기(+)는 한 번 이상 반복될 수 있지만 생략할 수는 없다는 뜻이고, 대괄호([])로 둘러싸인 것은 최대 한 번 나올 수 있고, 생략 가능하다는 뜻입니다. * 와 + 연산자는 최대한 엄격하게 연결됩니다; 우선순위가 가장 높습니다; 괄호는 덩어리로 묶는 데 사용됩니다. 문자열 리터럴은 따옴표로 둘러싸입니다. 공백은 토큰을 분리하는 용도로만 사용됩니다. 규칙은 보통 한 줄로 표현됩니다; 대안이 많은 규칙은 여러 줄로 표현될 수도 있는데, 뒤따르는 줄들이 세로막대로 시작되게 만듭니다.

어휘 정의 (위에서 든 예와 같이) 에서는, 두 가지 추가 관례가 사용됩니다: 두 개의 리터럴 문자가 세 개의 점으로 분리되어 있으면 주어진 (끝의 두 문자 모두 포함하는) 범위의 ASCII 문자 중 어느 하나라는 뜻입니다. 홑화살괄호(<...>) 안에 들어있는 구문은, 정의되는 기호에 대한 비형식적 설명을 제공합니다. 즉 필요한 경우 ‘제어 문자’를 설명하는데 사용될 수 있습니다.

사용되는 표기법이 거의 같다고 하더라도, 어휘와 문법 정의 간에는 커다란 차이가 있습니다: 어휘 정의는 입력의 개별 문자에 적용되는 반면, 문법 정의는 어휘 분석기가 만들어내는 토큰들에 적용됩니다. 다음 장 (“어휘 분석(Lexical Analysis)”)에서 사용되는 모든 BNF는 어휘 정의입니다; 그 이후의 장에서는 문법 정의입니다.

2. 어휘 분석

파이썬 프로그램은 파서(parser) 에 의해 읽힙니다. 파서의 입력은 어휘 분석기(lexical analyzer) 가 만들어내는 토큰(token) 들의 스트림입니다. 이 장에서는 어휘 분석기가 어떻게 파일을 토큰들로 분해하는지 설명합니다.

파이썬은 프로그램 텍스트를 유니코드 코드값으로 읽습니다; 소스 파일의 인코딩은 인코딩 선언을 통해 지정될 수 있고, 기본값은 UTF-8입니다. 자세한 내용은 PEP 3120 [https://peps.python.org/pep-3120/] 에 나옵니다. 소스 파일을 디코딩할 수 없을 때는 SyntaxError 가 발생합니다.

2.1. 줄 구조(Line structure)

파이썬 프로그램은 여러 개의 논리적인 줄(logical lines) 들로 나뉩니다.

2.1.1. 논리적인 줄

논리적인 줄의 끝은 NEWLINE 토큰으로 표현됩니다. 문법이 허락하지 않는 이상 (예를 들어 복합문에서 문장들 사이) 문장은 논리적인 줄 간의 경계를 가로지를 수 없습니다. 논리적인 줄은 명시적이거나 묵시적인 줄 결합(line joining) 규칙에 따라 하나 이상의 물리적인 줄(physical lines) 들로 구성됩니다.

2.1.2. 물리적인 줄

물리적인 줄은 줄의 끝을 나타내는 시퀀스로 끝나는 문자들의 시퀀스입니다. 소스 파일과 문자열에는 플랫폼들의 표준 줄 종료 시퀀스들이 모두 사용될 수 있습니다 - ASCII LF (개행문자)를 사용하는 유닉스 형, ASCII 시퀀스 CR LF(캐리지 리턴 다음에 오는 개행 문자)를 사용하는 윈도우 형, ASCII CR(캐리지 리턴)을 사용하는 예전의 매킨토시 형. 이 형태들은 플랫폼의 종류와 관계없이 동등하게 사용할 수 있습니다. 입력의 끝은 마지막 물리적인 줄의 묵시적 종결자 역할을 합니다.

파이썬을 내장할 때는, 소스 코드 문자열은 반드시 줄 종료 문자에 표준 C 관행(ASCII LF를 표현하는 \n 문자로 줄이 종료됩니다)을 적용해서 파이썬 API로 전달되어야 합니다.

2.1.3. 주석

주석은 문자열 리터럴에 포함되지 않는 해시 문자(#)로 시작하고 물리적인 줄의 끝에서 끝납니다. 묵시적인 줄 결합 규칙이 유효하지 않은 이상, 주석은 논리적인 줄을 종료시킵니다. 주석은 문법이 무시합니다.

2.1.4. 인코딩 선언

파이썬 스크립트의 첫 번 째나 두 번째 줄에 있는 주석이 정규식 coding[=:]\s*([-\w.]+) 과 매치되면, 이 주석은 인코딩 선언으로 처리됩니다. 이 정규식의 첫 번째 그룹은 소스 코드 파일의 인코딩 이름을 지정합니다. 인코딩 선언은 줄 전체에 홀로 나와야 합니다. 만약 두 번째 줄이라면, 첫 번째 줄 역시 주석만 있어야 합니다. 인코딩 선언의 권장 형태는 두 개입니다. 하나는

# -*- coding: <encoding-name> -*-

인데 GNU Emacs에서도 인식됩니다. 다른 하나는

# vim:fileencoding=<encoding-name>

인데 Bram Moolenaar 의 VIM에서 인식됩니다.

If no encoding declaration is found, the default encoding is UTF-8. If the implicit or explicit encoding of a file is UTF-8, an initial UTF-8 byte-order mark (b’xefxbbxbf’) is ignored rather than being a syntax error.

If an encoding is declared, the encoding name must be recognized by Python (see 표준 인코딩). The encoding is used for all lexical analysis, including string literals, comments and identifiers.

2.1.5. 명시적인 줄 결합

둘 이상의 물리적인 줄은 역 슬래시 문자(\)를 사용해서 논리적인 줄로 결합할 수 있습니다: 물리적인 줄이 문자열 리터럴이나 주석의 일부가 아닌 역 슬래시 문자로 끝나면, 역 슬래시와 뒤따르는 개행 문자가 제거된 채로, 현재 만들어지고 있는 논리적인 줄에 합쳐집니다. 예를 들어:

if 1900 < year < 2100 and 1 <= month <= 12 \
   and 1 <= day <= 31 and 0 <= hour < 24 \
   and 0 <= minute < 60 and 0 <= second < 60:   # Looks like a valid date
        return 1

역 슬래시로 끝나는 줄은 주석이 포함될 수 없습니다. 역 슬래시는 주석을 결합하지 못합니다. 역 슬래시는 문자열 리터럴을 제외한 어떤 토큰도 결합하지 못합니다 (즉, 문자열 리터럴 이외의 어떤 토큰도 역 슬래시를 사용해서 두 줄에 나누어 기록할 수 없습니다.). 문자열 리터럴 밖에 있는 역 슬래시가 앞에서 언급한 장소 이외의 곳에 등장하는 것은 문법에 어긋납니다.

2.1.6. 묵시적인 줄 결합

괄호(()), 대괄호([]), 중괄호({})가 사용되는 표현은 역 슬래시 없이도 여러 개의 물리적인 줄로 나눌 수 있습니다. 예를 들어:

month_names = ['Januari', 'Februari', 'Maart',      # These are the
               'April',   'Mei',      'Juni',       # Dutch names
               'Juli',    'Augustus', 'September',  # for the months
               'Oktober', 'November', 'December']   # of the year

묵시적으로 이어지는 줄들은 주석을 포함할 수 있습니다. 이어지는 줄들의 들여쓰기는 중요하지 않습니다. 중간에 빈 줄이 들어가도 됩니다. 묵시적으로 줄 결합하는 줄 들 간에는 NEWLINE 토큰이 만들어지지 않습니다. 묵시적으로 이어지는 줄들은 삼중 따옴표 된 문자열들에서도 등장할 수 있는데 (아래를 보라), 이 경우는 주석이 포함될 수 없습니다.

2.1.7. 빈 줄

스페이스, 탭, 폼 피드(formfeed) 와 주석만으로 구성된 논리적인 줄은 무시됩니다. (즉 NEWLINE 토큰이 만들어지지 않습니다.) 대화형으로 문장이 입력되는 도중에는 빈 줄의 처리가 REPL 구현에 따라 달라질 수 있습니다. 표준 대화형 인터프리터에서는, 완전히 빈 줄(즉 공백이나 주석조차 없는 것)은 다중 행 문장을 종료시킵니다.

2.1.8. 들여쓰기

논리적인 줄의 제일 앞에 오는 공백(스페이스와 탭)은 줄의 들여쓰기 수준을 계산하는 데 사용되고, 이는 다시 문장들의 묶음을 결정하는 데 사용되게 됩니다.

탭은 (왼쪽에서 오른쪽으로) 1~8개의 스페이스로 변환되는데, 치환된 후의 총 스페이스 문자 수가 8의 배수가 되도록 맞춥니다. (유닉스에서 사용되는 규칙에 맞추려는 것입니다.) 첫 번째 비 공백 문자 앞에 나오는 공백의 총수가 줄의 들여쓰기를 결정합니다. 들여쓰기는 역 슬래시를 사용해서 여러 개의 물리적인 줄로 나눠질 수 없습니다; 첫 번째 역 슬래시 이전의 공백이 들여쓰기를 결정합니다.

소스 파일이 탭과 스페이스를 섞어 쓰는 경우, 탭이 몇 개의 스페이스에 해당하는지에 따라 다르게 해석될 수 있으면 TabError 를 일으킵니다.

크로스-플랫폼 호환성 유의 사항: UNIX 이외의 플랫폼에서 편집기들이 동작하는 방식 때문에, 하나의 파일 내에서 들여쓰기를 위해 탭과 스페이스를 섞어 쓰는 것은 현명한 선택이 아닙니다. 다른 플랫폼들에서는 최대 들여쓰기 수준에 제한이 있을 수도 있다는 점도 주의해야 합니다.

폼 피드 문자는 줄의 처음에 나올 수 있습니다; 앞서 설명한 들여쓰기 수준 계산에서는 무시됩니다. 페이지 넘김 문자 앞에 공백이나 탭이 있는 경우는 정의되지 않은 효과를 줄 수 있습니다 (가령, 스페이스 수가 0으로 초기화될 수 있습니다).

연속된 줄의 들여쓰기 수준은, 스택을 사용해서, 다음과 같은 방법으로 INDENT와 DEDENT 토큰을 만드는 데 사용됩니다.

파일의 첫 줄을 읽기 전에 0하나를 스택에 넣습니다(push); 이 값은 다시 꺼내는(pop) 일이 없습니다. 스택에 넣는 값은 항상 스택의 아래에서 위로 올라갈 때 단조 증가합니다. 각 논리적인 줄의 처음에서 줄의 들여쓰기 수준이 스택의 가장 위에 있는 값과 비교됩니다. 같다면 아무런 일도 일어나지 않습니다. 더 크다면 그 값을 스택에 넣고 하나의 INDENT 토큰을 만듭니다. 더 작다면 이 값은 스택에 있는 값 중 하나여야만 합니다. 이 값보다 큰 모든 스택의 값들을 꺼내고(pop), 꺼낸 횟수만큼의 DEDENT 토큰을 만듭니다. 파일의 끝에서, 스택에 남아있는 0보다 큰 값의 개수만큼 DEDENT 토큰을 만듭니다.

여기에 (혼란스럽다 할지라도) 올바르게 들여쓰기 된 파이썬 코드 조각이 있습니다:

def perm(l):
        # Compute the list of all permutations of l
    if len(l) <= 1:
                  return [l]
    r = []
    for i in range(len(l)):
             s = l[:i] + l[i+1:]
             p = perm(s)
             for x in p:
              r.append(l[i:i+1] + x)
    return r

다음 예는 여러 가지 들여쓰기 에러를 보여줍니다:

 def perm(l):                       # error: first line indented
for i in range(len(l)):             # error: not indented
    s = l[:i] + l[i+1:]
        p = perm(l[:i] + l[i+1:])   # error: unexpected indent
        for x in p:
                r.append(l[i:i+1] + x)
            return r                # error: inconsistent dedent

(사실, 처음 세 개의 에러는 파서가 감지합니다. 단지 마지막 에러만 어휘 분석기가 감지합니다. — return r 의 들여쓰기가 스택에 있는 값과 일치하지 않습니다.)

2.1.9. 토큰 사이의 공백

논리적인 줄의 처음과 문자열 리터럴을 제외하고, 공백 문자인 스페이스, 탭, 폼 피드는 토큰을 분리하기 위해 섞어 쓸 수 있습니다. 두 토큰을 붙여 쓸 때 다른 토큰으로 해석될 수 있는 경우만 토큰 사이에 공백이 필요합니다. (예를 들어, ab 는 하나의 토큰이지만, a b 는 두 개의 토큰입니다.)

2.2. 다른 토큰들

NEWLINE, INDENT, DEDENT 와는 별도로, 다음과 같은 유형의 토큰들이 존재합니다: 식별자(identifier), 키워드(keyword), 리터럴(literal), 연산자(operator), 구분자(delimiter). (앞에서 살펴본 줄 종료 이외의) 공백 문자들은 토큰이 아니지만, 토큰을 분리하는 역할을 담당합니다. 모호할 경우, 왼쪽에서 오른쪽으로 읽을 때, 하나의 토큰은 올바르고 가능한 한 최대 길이의 문자열로 구성되는 것을 선호합니다.

2.3. 식별자와 키워드

식별자 (이름(name) 이라고도 합니다) 은 다음과 같은 어휘 정의로 기술됩니다.

파이썬에서 식별자의 문법은 유니코드 표준 부속서 UAX-31 에 기반을 두는데, 여기에 덧붙이거나 바꾼 내용은 아래에서 정의합니다. 좀 더 상세한 내용은 PEP 3131 [https://peps.python.org/pep-3131/] 에서 찾을 수 있습니다.

Within the ASCII range (U+0001..U+007F), the valid characters for identifiers include the uppercase and lowercase letters A through Z, the underscore _ and, except for the first character, the digits 0 through 9. Python 3.0 introduced additional characters from outside the ASCII range (see PEP 3131 [https://peps.python.org/pep-3131/]). For these characters, the classification uses the version of the Unicode Character Database as included in the unicodedata module.

식별자는 길이에 제한이 없고, 케이스(case)는 구분됩니다.

identifier   ::=  xid_start xid_continue*
id_start     ::=  <all characters in general categories Lu, Ll, Lt, Lm, Lo, Nl, the underscore, and characters with the Other_ID_Start property>
id_continue  ::=  <all characters in id_start, plus characters in the categories Mn, Mc, Nd, Pc and others with the Other_ID_Continue property>
xid_start    ::=  <all characters in id_start whose NFKC normalization is in "id_start xid_continue*">
xid_continue ::=  <all characters in id_continue whose NFKC normalization is in "id_continue*">

위에서 언급한 유니코드 카테고리 코드들의 의미는 이렇습니다:

Lu - uppercase letters

Ll - lowercase letters

Lt - titlecase letters

Lm - modifier letters

Lo - other letters

Nl - letter numbers

Mn - nonspacing marks

Mc - spacing combining marks

Nd - decimal numbers

Pc - connector punctuations

Other_ID_Start - explicit list of characters in PropList.txt [https://www.unicode.org/Public/16.0.0/ucd/PropList.txt] to support backwards compatibility

Other_ID_Continue - 마찬가지

모든 식별자는 파서에 의해 NFKC 정규화 형식으로 변환되고, 식별자의 비교는 NFKC 에 기반을 둡니다.

A non-normative HTML file listing all valid identifier characters for Unicode 16.0.0 can be found at https://www.unicode.org/Public/16.0.0/ucd/DerivedCoreProperties.txt

2.3.1. 키워드

다음 식별자들은 예약어, 또는 언어의 키워드, 로 사용되고, 일반적인 식별자로 사용될 수 없습니다. 여기 쓰여 있는 것과 정확히 같게 사용되어야 합니다:

False      await      else       import     pass
None       break      except     in         raise
True       class      finally    is         return
and        continue   for        lambda     try
as         def        from       nonlocal   while
assert     del        global     not        with
async      elif       if         or         yield

2.3.2. Soft Keywords

Added in version 3.10.

Some identifiers are only reserved under specific contexts. These are known as soft keywords. The identifiers match, case, type and _ can syntactically act as keywords in certain contexts, but this distinction is done at the parser level, not when tokenizing.

As soft keywords, their use in the grammar is possible while still preserving compatibility with existing code that uses these names as identifier names.

match, case, and _ are used in the match statement. type is used in the type statement.

버전 3.12에서 변경: type is now a soft keyword.

2.3.3. 식별자의 예약 영역

(키워드와는 별개로) 어떤 부류의 식별자들은 특별한 의미가 있습니다. 이 부류의 식별자들은 시작과 끝의 밑줄 문자 패턴으로 구분됩니다:

_*

Not imported by from module import *.

_

In a case pattern within a match statement, _ is a soft keyword that denotes a wildcard.

Separately, the interactive interpreter makes the result of the last evaluation available in the variable _. (It is stored in the builtins module, alongside built-in functions like print.)

Elsewhere, _ is a regular identifier. It is often used to name “special” items, but it is not special to Python itself.

참고

이름 _ 은 종종 국제화(internationalization)와 관련되어 사용됩니다. 이 관례에 관해서는 gettext 모듈의 문서를 참조하십시오.

It is also commonly used for unused variables.

__*__

시스템 정의 이름, 비공식적으로 “던더(dunder)” 이름이라고 알려졌습니다. 이 이름들은 인터프리터와 그 구현(표준 라이브러리를 포함합니다)이 정의합니다. 현재 정의된 시스템 이름은 특수 메서드 이름들 섹션과 그 외의 곳에서 논의됩니다. 파이썬의 미래 버전에서는 더 많은 것들이 정의될 가능성이 큽니다. 어떤 문맥에서건, 명시적으로 문서로 만들어진 사용법을 벗어나는 __*__ 이름의 모든 사용은, 경고 없이 손상될 수 있습니다.

__*

클래스-비공개 이름. 이 부류의 이름들을 클래스 정의 문맥에서 사용하면 뒤섞인 형태로 변형됩니다. 부모 클래스와 자식 클래스의 “비공개(private)” 어트리뷰트 간의 이름 충돌을 피하기 위함입니다. 식별자 (이름) 섹션을 보세요.

2.4. 리터럴

리터럴(literal)은 몇몇 내장형들의 상숫값을 위한 표기법입니다.

2.4.1. 문자열과 바이트열 리터럴

문자열 리터럴은 다음과 같은 어휘 정의로 기술됩니다:

stringliteral   ::=  [stringprefix](shortstring | longstring)
stringprefix    ::=  "r" | "u" | "R" | "U" | "f" | "F"
                     | "fr" | "Fr" | "fR" | "FR" | "rf" | "rF" | "Rf" | "RF"
shortstring     ::=  "'" shortstringitem* "'" | '"' shortstringitem* '"'
longstring      ::=  "'''" longstringitem* "'''" | '"""' longstringitem* '"""'
shortstringitem ::=  shortstringchar | stringescapeseq
longstringitem  ::=  longstringchar | stringescapeseq
shortstringchar ::=  <any source character except "\" or newline or the quote>
longstringchar  ::=  <any source character except "\">
stringescapeseq ::=  "\" <any source character>

bytesliteral   ::=  bytesprefix(shortbytes | longbytes)
bytesprefix    ::=  "b" | "B" | "br" | "Br" | "bR" | "BR" | "rb" | "rB" | "Rb" | "RB"
shortbytes     ::=  "'" shortbytesitem* "'" | '"' shortbytesitem* '"'
longbytes      ::=  "'''" longbytesitem* "'''" | '"""' longbytesitem* '"""'
shortbytesitem ::=  shortbyteschar | bytesescapeseq
longbytesitem  ::=  longbyteschar | bytesescapeseq
shortbyteschar ::=  <any ASCII character except "\" or newline or the quote>
longbyteschar  ::=  <any ASCII character except "\">
bytesescapeseq ::=  "\" <any ASCII character>

One syntactic restriction not indicated by these productions is that whitespace is not allowed between the stringprefix or bytesprefix and the rest of the literal. The source character set is defined by the encoding declaration; it is UTF-8 if no encoding declaration is given in the source file; see section 인코딩 선언.

In plain English: Both types of literals can be enclosed in matching single quotes (') or double quotes ("). They can also be enclosed in matching groups of three single or double quotes (these are generally referred to as triple-quoted strings). The backslash (\) character is used to give special meaning to otherwise ordinary characters like n, which means ‘newline’ when escaped (\n). It can also be used to escape characters that otherwise have a special meaning, such as newline, backslash itself, or the quote character. See escape sequences below for examples.

바이트열(bytes) 리터럴은 항상 'b' 나 'B' 를 앞에 붙입니다; str 형의 인스턴스 대신 bytes 형의 인스턴스를 만듭니다. 오직 ASCII 문자들만 포함할 수 있습니다. 코드값이 128보다 크거나 같은 값들은 반드시 이스케이핑으로 표현되어야 합니다.

Both string and bytes literals may optionally be prefixed with a letter 'r' or 'R'; such constructs are called raw string literals and raw bytes literals respectively and treat backslashes as literal characters. As a result, in raw string literals, '\U' and '\u' escapes are not treated specially.

Added in version 3.3: 날 바이트열 리터럴의 'br' 와 같은 의미가 있는 'rb' 접두어가 추가되었습니다.

파이썬 2.x 와 3.x 에서 동시에 지원하는 코드들의 유지보수를 단순화하기 위해 예전에 사용되던 유니코드 리터럴 (u'value')이 다시 도입되었습니다. 자세한 정보는 PEP 414 [https://peps.python.org/pep-0414/] 에 나옵니다.

'f' 나 'F' 를 접두어로 갖는 문자열 리터럴은 포맷 문자열 리터럴(formatted string literal)입니다; f-strings 을 보세요. 'f' 는 'r' 과 결합할 수 있습니다, 하지만, 'b' 나 'u' 와는 결합할 수 없습니다. 따라서 날 포맷 문자열은 가능하지만, 포맷 바이트열 리터럴은 불가능합니다.

삼중 따옴표 된 리터럴에서, 세 개의 이스케이핑 되지 않은 개행 문자와 따옴표가 허락됩니다 (그리고 유지됩니다). 예외는 한 줄에 세 개의 이스케이핑 되지 않은 따옴표가 나오는 것인데, 리터럴을 종료시킵니다. (“따옴표”는 리터럴을 시작하는데 사용한 문자입니다. 즉, ' 나 ")

2.4.1.1. Escape sequences

'r' 나 'R' 접두어가 붙지 않은 이상, 문자열과 바이트열 리터럴에 포함된 이스케이프 시퀀스는 표준 C에서 사용된 것과 비슷한 규칙으로 해석됩니다. 인식되는 이스케이프 시퀀스는 이렇습니다:

이스케이프 시퀀스

의미

유의 사항

\<newline>

역 슬래시와 개행 문자가 무시됩니다

(1)

\\

역 슬래시 (\)

\'

작은따옴표 (')

\"

큰따옴표 (")

\a

ASCII 벨 (BEL)

\b

ASCII 백스페이스 (BS)

\f

ASCII 폼 피드 (FF)

\n

ASCII 라인 피드 (LF)

\r

ASCII 캐리지 리턴 (CR)

\t

ASCII 가로 탭 (TAB)

\v

ASCII 세로 탭 (VT)

\ooo

8진수 ooo 로 지정된 문자

(2,4)

\xhh

16진수 hh 로 지정된 문자

(3,4)

문자열 리터럴에서만 인식되는 이스케이프 시퀀스는:

이스케이프 시퀀스

의미

유의 사항

\N{name}

유니코드 데이터베이스에서 name 이라고 이름 붙여진 문자

(5)

\uxxxx

16-bit 16진수 xxxx 로 지정된 문자

(6)

\Uxxxxxxxx

32-bit 16진수 xxxxxxxx 로 지정된 문자

(7)

유의 사항:

A backslash can be added at the end of a line to ignore the newline:

>>> 'This string will not include \
... backslashes or newline characters.'
'This string will not include backslashes or newline characters.'

The same result can be achieved using triple-quoted strings, or parentheses and string literal concatenation.

표준 C와 마찬가지로, 최대 세 개의 8진수가 허용됩니다.

버전 3.11에서 변경: Octal escapes with value larger than 0o377 produce a DeprecationWarning.

버전 3.12에서 변경: Octal escapes with value larger than 0o377 produce a SyntaxWarning. In a future Python version they will be eventually a SyntaxError.

표준 C와는 달리, 정확히 두 개의 16진수가 제공되어야 합니다.

바이트열 리터럴에서, 16진수와 8진수 이스케이프는 지정된 값의 바이트를 표현합니다. 문자열 리터럴에서는, 이 이스케이프는 지정된 값의 유니코드 문자를 표현합니다.

버전 3.3에서 변경: 별칭 [1] 지원이 추가되었습니다

정확히 4개의 16진수를 필요로 합니다.

이 방법으로 모든 유니코드를 인코딩할 수 있습니다. 정확히 8개의 16진수가 필요합니다.

표준 C와는 달리, 인식되지 않는 모든 이스케이프 시퀀스는 문자열에 변경되지 않은 상태로 남게 됩니다. 즉, 역 슬래시가 결과에 남게 됩니다. (이 동작은 디버깅할 때 쓸모가 있습니다. 이스케이프 시퀀스가 잘못 입력되었을 때, 최종 결과에서 잘못된 부분을 쉽게 인지할 수 있습니다.) 문자열 리터럴에서만 인식되는 이스케이프 시퀀스가, 바이트열 리터럴에서는 인식되지 않는 부류임에 주목하십시오.

버전 3.6에서 변경: Unrecognized escape sequences produce a DeprecationWarning.

버전 3.12에서 변경: Unrecognized escape sequences produce a SyntaxWarning. In a future Python version they will be eventually a SyntaxError.

날 리터럴에서 조차, 따옴표는 역 슬래시로 이스케이프 됩니다. 하지만 역 슬래시가 결과에 남게 됩니다; 예를 들어, r"\"" 는 올바른 문자열 리터럴인데, 두 개의 문자가 들어있습니다: 역 슬래시와 큰따옴표; r"\" 는 올바른 문자열 리터럴이 아닙니다 (날 문자열조차 홀수개의 역 슬래시로 끝날 수 없습니다.). 좀 더 명확하게 말하자면, 날 리터럴은 하나의 역 슬래시로 끝날 수 없습니다(역 슬래시가 뒤에 오는 따옴표를 이스케이프 시키기 때문입니다). 역 슬래시와 바로 뒤에 오는 개행문자는 줄 결합이 아니라 리터럴에 포함되는 두 개의 문자로 인식됨에 주의해야 합니다.

2.4.2. 문자열 리터럴 이어붙이기

여러 개의 문자열이나 바이트열 리터럴을 (공백으로 분리해서) 여러 개 인접해서 나열하는 것이 허락되고, 그 의미는 이어붙인 것과 같습니다. 각 리터럴이 서로 다른 따옴표를 사용해도 됩니다. 그래서, "hello" 'world' 는 "helloworld" 와 동등합니다. 이 기능은 긴 문자열을 편의상 여러 줄로 나눌 때 필요한 역 슬래시를 줄여줍니다. 각 문자열 단위마다 주석을 붙이는 것도 가능합니다. 예를 들어:

re.compile("[A-Za-z_]"       # letter or underscore
           "[A-Za-z0-9_]*"   # letter, digit or underscore
          )

이 기능이 문법 수준에서 정의되고는 있지만, 컴파일 시점에 구현됨에 주의해야 합니다. 실행 시간에 문자열 표현을 이어붙이기 위해서는 ‘+’ 연산자를 사용해야 합니다. 리터럴 이어붙이기가 요소별로 다른 따옴표를 사용할 수 있고 (날 문자열과 삼중 따옴표 문자열을 이어붙이는 것조차 가능합니다), 포맷 문자열 리터럴을 보통 문자열 리터럴과 이어붙일 수 있음에 유의해야 합니다.

2.4.3. f-strings

Added in version 3.6.

포맷 문자열 리터럴(formatted string literal) 또는 f-문자열 (f-string) 은 'f' 나 'F' 를 앞에 붙인 문자열 리터럴입니다. 이 문자열은 치환 필드를 포함할 수 있는데, 중괄호 {} 로 구분되는 표현식입니다. 다른 문자열 리터럴이 항상 상숫값을 갖지만, 포맷 문자열 리터럴은 실행시간에 계산되는 표현식입니다.

이스케이프 시퀀스는 일반 문자열 리터럴처럼 디코딩됩니다 (동시에 날 문자열인 경우는 예외입니다). 디코딩 후에 문자열의 내용은 다음과 같은 문법을 따릅니다:

f_string          ::=  (literal_char | "{{" | "}}" | replacement_field)*
replacement_field ::=  "{" f_expression ["="] ["!" conversion] [":" format_spec] "}"
f_expression      ::=  (conditional_expression | "*" or_expr)
                         ("," conditional_expression | "," "*" or_expr)* [","]
                       | yield_expression
conversion        ::=  "s" | "r" | "a"
format_spec       ::=  (literal_char | replacement_field)*
literal_char      ::=  <any code point except "{", "}" or NULL>

중괄호 바깥 부분은 일반 리터럴처럼 취급되는데, 이중 중괄호 '{{' 나 '}}' 가 대응하는 단일 중괄호로 치환된다는 점만 예외입니다. 하나의 여는 중괄호 '{' 는 치환 필드를 시작시키는데, 파이썬 표현식이 뒤따릅니다. 평가 후 표현식 텍스트와 해당 값을 모두 표시하려면 (디버깅에 유용합니다), 표현식 뒤에 등호 `` ‘=’\를 추가할 수 있습니다. 느낌표 ``'!' 로 시작하는, 변환(conversion) 필드가 뒤따를 수 있습니다. 포맷 지정자(format specifier)도 덧붙일 수 있는데, 콜론 ':' 으로 시작합니다. 치환 필드는 닫는 중괄호 '}' 로 끝납니다.

Expressions in formatted string literals are treated like regular Python expressions surrounded by parentheses, with a few exceptions. An empty expression is not allowed, and both lambda and assignment expressions := must be surrounded by explicit parentheses. Each expression is evaluated in the context where the formatted string literal appears, in order from left to right. Replacement expressions can contain newlines in both single-quoted and triple-quoted f-strings and they can contain comments. Everything that comes after a # inside a replacement field is a comment (even closing braces and quotes). In that case, replacement fields must be closed in a different line.

>>> f"abc{a # This is a comment }"
... + 3}"
'abc5'

버전 3.7에서 변경: 파이썬 3.7 이전에는, 구현 문제로 인해 포맷 문자열 리터럴의 표현식에서 await 표현식과 async for 절을 포함하는 컴프리헨션은 유효하지 않았습니다.

버전 3.12에서 변경: Prior to Python 3.12, comments were not allowed inside f-string replacement fields.

등호 기호 '='이 제공되면, 출력에는 표현식 텍스트, '=' 및 평가된 값이 포함됩니다. 여는 중괄호 '{' 뒤, 표현식 내, '=' 뒤의 스페이스는 모두 출력에 유지됩니다. 기본적으로, '='은 포맷 지정자가 없는 한 표현식의 repr()을 제공합니다. 포맷이 지정되면 변환 '!r'이 선언되지 않는 한 기본적으로 표현식의 str()이 사용됩니다.

Added in version 3.8: 등호 기호 '='.

변환(conversion)이 지정되면, 표현식의 결과가 포매팅 전에 변환됩니다. 변환 '!s' 는 결과에 str() 을 호출하고, '!r' 은 repr() 을 호출하고, '!a' 은 ascii() 를 호출합니다.

The result is then formatted using the format() protocol. The format specifier is passed to the __format__() method of the expression or conversion result. An empty string is passed when the format specifier is omitted. The formatted result is then included in the final value of the whole string.

Top-level format specifiers may include nested replacement fields. These nested fields may include their own conversion fields and format specifiers, but may not include more deeply nested replacement fields. The format specifier mini-language is the same as that used by the str.format() method.

포맷 문자열 리터럴을 이어붙일 수는 있지만, 치환 필드가 여러 리터럴로 쪼개질 수는 없습니다.

포맷 문자열 리터럴의 예를 들면:

>>> name = "Fred"
>>> f"He said his name is {name!r}."
"He said his name is 'Fred'."
>>> f"He said his name is {repr(name)}."  # repr() is equivalent to !r
"He said his name is 'Fred'."
>>> width = 10
>>> precision = 4
>>> value = decimal.Decimal("12.34567")
>>> f"result: {value:{width}.{precision}}"  # nested fields
'result:      12.35'
>>> today = datetime(year=2017, month=1, day=27)
>>> f"{today:%B %d, %Y}"  # using date format specifier
'January 27, 2017'
>>> f"{today=:%B %d, %Y}" # using date format specifier and debugging
'today=January 27, 2017'
>>> number = 1024
>>> f"{number:#0x}"  # using integer format specifier
'0x400'
>>> foo = "bar"
>>> f"{ foo = }" # preserves whitespace
" foo = 'bar'"
>>> line = "The mill's closed"
>>> f"{line = }"
'line = "The mill\'s closed"'
>>> f"{line = :20}"
"line = The mill's closed   "
>>> f"{line = !r:20}"
'line = "The mill\'s closed" '

Reusing the outer f-string quoting type inside a replacement field is permitted:

>>> a = dict(x=2)
>>> f"abc {a["x"]} def"
'abc 2 def'

버전 3.12에서 변경: Prior to Python 3.12, reuse of the same quoting type of the outer f-string inside a replacement field was not possible.

Backslashes are also allowed in replacement fields and are evaluated the same way as in any other context:

>>> a = ["a", "b", "c"]
>>> print(f"List a contains:\n{"\n".join(a)}")
List a contains:
a
b
c

버전 3.12에서 변경: Prior to Python 3.12, backslashes were not permitted inside an f-string replacement field.

포맷 문자열 리터럴은 독스트링(docstring)으로 사용될 수 없습니다. 표현식이 전혀 없더라도 마찬가집니다.

>>> def foo():
...     f"Not a docstring"
...
>>> foo.__doc__ is None
True

포맷 문자열 리터럴 추가에 대한 제안은 PEP 498 [https://peps.python.org/pep-0498/] 을 참조하고, 관련된 포맷 문자열 메커니즘을 사용하는 str.format() 도 살펴보는 것이 좋습니다.

2.4.4. 숫자 리터럴

There are three types of numeric literals: integers, floating-point numbers, and imaginary numbers. There are no complex literals (complex numbers can be formed by adding a real number and an imaginary number).

숫자 리터럴이 부호를 포함하지 않는 것에 주의해야 합니다; -1 과 같은 구문은 일 항 연산자 ‘-’ 과 리터럴 1 로 구성된 표현식입니다.

2.4.5. 정수 리터럴

정수 리터럴은 다음과 같은 어휘 정의로 표현됩니다:

integer      ::=  decinteger | bininteger | octinteger | hexinteger
decinteger   ::=  nonzerodigit (["_"] digit)* | "0"+ (["_"] "0")*
bininteger   ::=  "0" ("b" | "B") (["_"] bindigit)+
octinteger   ::=  "0" ("o" | "O") (["_"] octdigit)+
hexinteger   ::=  "0" ("x" | "X") (["_"] hexdigit)+
nonzerodigit ::=  "1"..."9"
digit        ::=  "0"..."9"
bindigit     ::=  "0" | "1"
octdigit     ::=  "0"..."7"
hexdigit     ::=  digit | "a"..."f" | "A"..."F"

가용한 메모리에 저장될 수 있는지와는 별개로 정수 리터럴의 길이에 제한은 없습니다.

밑줄은 리터럴의 숫자 값을 결정할 때 고려되지 않습니다. 가독성을 높이기 위해 숫자들을 무리 지을 때 쓸모가 있습니다. 밑줄은 숫자 사이나 0x 와 같은 진수 지정자(base specifier) 다음에 나올 수 있는데, 한 번에 하나만 사용될 수 있습니다.

0 이 아닌 10진수가 0으로 시작할 수 없음에 주의해야 합니다. 3.0 버전 이전의 파이썬에서 사용한 C 스타일의 8진수 리터럴과 혼동되는 것을 막기 위함입니다.

정수 리터럴의 예를 들면:

7     2147483647                        0o177    0b100110111
3     79228162514264337593543950336     0o377    0xdeadbeef
      100_000_000_000                   0b_1110_0101

버전 3.6에서 변경: 리터럴에서 숫자들의 그룹을 표현할 목적으로 밑줄을 허락합니다.

2.4.6. Floating-point literals

Floating-point literals are described by the following lexical definitions:

floatnumber   ::=  pointfloat | exponentfloat
pointfloat    ::=  [digitpart] fraction | digitpart "."
exponentfloat ::=  (digitpart | pointfloat) exponent
digitpart     ::=  digit (["_"] digit)*
fraction      ::=  "." digitpart
exponent      ::=  ("e" | "E") ["+" | "-"] digitpart

Note that the integer and exponent parts are always interpreted using radix 10. For example, 077e010 is legal, and denotes the same number as 77e10. The allowed range of floating-point literals is implementation-dependent. As in integer literals, underscores are supported for digit grouping.

Some examples of floating-point literals:

3.14    10.    .001    1e100    3.14e-10    0e0    3.14_15_93

버전 3.6에서 변경: 리터럴에서 숫자들의 그룹을 표현할 목적으로 밑줄을 허락합니다.

2.4.7. 허수 리터럴

허수 리터럴은 다음과 같은 어휘 정의로 표현됩니다:

imagnumber ::=  (floatnumber | digitpart) ("j" | "J")

An imaginary literal yields a complex number with a real part of 0.0. Complex numbers are represented as a pair of floating-point numbers and have the same restrictions on their range. To create a complex number with a nonzero real part, add a floating-point number to it, e.g., (3+4j). Some examples of imaginary literals:

3.14j   10.j    10j     .001j   1e100j   3.14e-10j   3.14_15_93j

2.5. 연산자

다음과 같은 토큰들은 연산자입니다:

+       -       *       **      /       //      %      @
<<      >>      &       |       ^       ~       :=
<       >       <=      >=      ==      !=

2.6. 구분자

다음 토큰들은 문법에서 구분자(delimiter)로 기능합니다:

(       )       [       ]       {       }
,       :       !       .       ;       @       =
->      +=      -=      *=      /=      //=     %=
@=      &=      |=      ^=      >>=     <<=     **=

마침표는 실수와 허수 리터럴에서도 등장할 수 있습니다. 연속된 마침표 세 개는 생략부호 리터럴(ellipsis literal)이라는 특별한 의미가 있습니다. 목록 후반의 증분 대입 연산자(augmented assignment operator)들은 어휘적으로는 구분자로 기능하지만, 동시에 연산을 수행합니다.

다음의 인쇄되는 ASCII 문자들은 다른 토큰들 일부로서 특별한 의미가 있거나, 그렇지 않으면 어휘 분석기에 유의미합니다:

'       "       #       \

다음의 인쇄되는 ASCII 문자들은 파이썬에서 사용되지 않습니다. 문자열 리터럴과 주석 이외의 곳에서 사용되는 것은 조건 없는 에러입니다:

$       ?       `

각주

[1]

https://www.unicode.org/Public/16.0.0/ucd/NameAliases.txt

3. 데이터 모델

3.1. 객체, 값, 형

객체 (Objects)는 파이썬이 데이터(data)를 추상화한 것(abstraction)입니다. 파이썬 프로그램의 모든 데이터는 객체나 객체 간의 관계로 표현됩니다. (폰 노이만(Von Neumann)의 “프로그램 내장식 컴퓨터(stored program computer)” 모델을 따르고, 또 그 관점에서 코드 역시 객체로 표현됩니다.)

Every object has an identity, a type and a value. An object’s identity never changes once it has been created; you may think of it as the object’s address in memory. The is operator compares the identity of two objects; the id() function returns an integer representing its identity.

CPython 구현 상세: CPython 의 경우, id(x) 는 x 가 저장된 메모리의 주소입니다.

객체의 형은 객체가 지원하는 연산들을 정의하고 (예를 들어, “길이를 갖고 있나?”) 그 형의 객체들이 가질 수 있는 가능한 값들을 정의합니다. type() 함수는 객체의 형(이것 역시 객체다)을 돌려줍니다. 아이덴티티와 마찬가지로, 객체의 형 (type) 역시 변경되지 않습니다. [1]

어떤 객체들의 값 은 변경할 수 있습니다. 값을 변경할 수 있는 객체들을 가변(mutable) 이라고 합니다. 일단 만들어진 후에 값을 변경할 수 없는 객체들을 불변(immutable) 이라고 합니다. (가변 객체에 대한 참조를 저장하고 있는 불변 컨테이너의 값은 가변 객체의 값이 변할 때 변경된다고 볼 수도 있습니다; 하지만 저장하고 있는 객체들의 집합이 바뀔 수 없으므로 컨테이너는 여전히 불변이라고 여겨집니다. 따라서 불변성은 엄밀하게는 변경 불가능한 값을 갖는 것과는 다릅니다. 좀 더 미묘합니다.) 객체의 가변성(mutability)은 그것의 형에 의해 결정됩니다; 예를 들어 숫자, 문자열, 튜플(tuple)은 불변이지만, 딕셔너리(dictionary) 와 리스트(list)는 가변입니다.

객체는 결코 명시적으로 파괴되지 않습니다; 더 참조되지 않을 때(unreachable) 가비지 수거(garbage collect)됩니다. 구현이 가비지 수거를 지연시키거나 아예 생략하는 것이 허락됩니다 — 아직 참조되는 객체들을 수거하지 않는 이상 가비지 수거가 어떤 식으로 구현되는지는 구현의 품질 문제입니다.

CPython 구현 상세: CPython 은 현재 참조 횟수 계산(reference-counting) 방식을 사용하는데, (선택 사항으로) 순환적으로 연결된 가비지의 지연된 감지가 추가됩니다. 이 방법으로 대부분 객체를 참조가 제거되자마자 수거할 수 있습니다. 하지만 순환 참조가 있는 가비지들을 수거한다는 보장은 없습니다. 순환적 가비지 수거의 제어에 관한 정보는 gc 모듈 문서를 참조하면 됩니다. 다른 구현들은 다른 식으로 동작하고, CPython 도 변경될 수 있습니다. 참조가 제거될 때 즉각적으로 파이널리제이션(finalization)되는 것에 의존하지 말아야 합니다 (그래서 항상 파일을 명시적으로 닫아주어야 합니다).

Note that the use of the implementation’s tracing or debugging facilities may keep objects alive that would normally be collectable. Also note that catching an exception with a try…except statement may keep objects alive.

Some objects contain references to “external” resources such as open files or windows. It is understood that these resources are freed when the object is garbage-collected, but since garbage collection is not guaranteed to happen, such objects also provide an explicit way to release the external resource, usually a close() method. Programs are strongly recommended to explicitly close such objects. The try…finally statement and the with statement provide convenient ways to do this.

어떤 객체들은 다른 객체에 대한 참조를 포함하고 있습니다. 이런 것들을 컨테이너(container) 라고 부릅니다. 튜플, 리스트, 딕셔너리등이 컨테이너의 예입니다. 이 참조들은 컨테이너의 값의 일부입니다. 대부분은, 우리가 컨테이너의 값을 논할 때는, 들어있는 객체들의 아이덴티티 보다는 값을 따집니다. 하지만, 컨테이너의 가변성에 대해 논할 때는 직접 가진 객체들의 아이덴티티만을 따집니다. 그래서, (튜플 같은) 불변 컨테이너가 가변 객체로의 참조를 하고 있다면, 그 가변 객체가 변경되면 컨테이너의 값도 변경됩니다.

Types affect almost all aspects of object behavior. Even the importance of object identity is affected in some sense: for immutable types, operations that compute new values may actually return a reference to any existing object with the same type and value, while for mutable objects this is not allowed. For example, after a = 1; b = 1, a and b may or may not refer to the same object with the value one, depending on the implementation. This is because int is an immutable type, so the reference to 1 can be reused. This behaviour depends on the implementation used, so should not be relied upon, but is something to be aware of when making use of object identity tests. However, after c = []; d = [], c and d are guaranteed to refer to two different, unique, newly created empty lists. (Note that e = f = [] assigns the same object to both e and f.)

3.2. 표준형 계층

아래에 파이썬에 내장된 형들의 목록이 있습니다. (구현에 따라 C 나 자바나 다른 언어로 작성된) 확장 모듈들은 추가의 형을 정의할 수 있습니다. 파이썬의 미래 버전 역시 형 계층에 형을 더할 수 있는데 (예를 들어, 유리수, 효율적으로 저장된 정수 배열 등등), 표준 라이브러리를 통해 추가될 가능성이 더 크기는 합니다.

아래에 나오는 몇몇 형에 대한 설명은 ‘특수 어트리뷰트(special attribute)’ 를 나열하는 문단을 포함합니다. 이것들은 구현에 접근할 방법을 제공하는데, 일반적인 사용을 위한 것이 아닙니다. 정의는 앞으로 변경될 수 있습니다.

3.2.1. None

이 형은 하나의 값만을 갖습니다. 이 값을 갖는 하나의 객체가 존재합니다. 이 객체에는 내장된 이름 None 을 통해 접근합니다. 여러 가지 상황에서 값의 부재를 알리는 데 사용됩니다. 예를 들어, 명시적으로 뭔가를 돌려주지 않는 함수의 반환 값입니다. 논리값은 거짓입니다.

3.2.2. NotImplemented

This type has a single value. There is a single object with this value. This object is accessed through the built-in name NotImplemented. Numeric methods and rich comparison methods should return this value if they do not implement the operation for the operands provided. (The interpreter will then try the reflected operation, or some other fallback, depending on the operator.) It should not be evaluated in a boolean context.

더 자세한 내용은 산술 연산 구현 을 참고하십시오.

버전 3.9에서 변경: Evaluating NotImplemented in a boolean context was deprecated.

버전 3.14에서 변경: Evaluating NotImplemented in a boolean context now raises a TypeError. It previously evaluated to True and emitted a DeprecationWarning since Python 3.9.

3.2.3. Ellipsis

이 형은 하나의 값만을 갖습니다. 이 값을 갖는 하나의 객체가 존재합니다. 이 객체에는 리터럴 ... 이나 내장된 이름 Ellipsis 을 통해 접근합니다. 논리값은 참입니다.

3.2.4. numbers.Number

이것들은 숫자 리터럴에 의해 만들어지고, 산술 연산과 내장 산술 함수들이 결과로 돌려줍니다. 숫자 객체는 불변입니다; 한 번 값이 만들어지면 절대 변하지 않습니다. 파이썬의 숫자는 당연히 수학적인 숫자들과 밀접하게 관련되어 있습니다, 하지만 컴퓨터의 숫자 표현상의 제약을 받고 있습니다.

The string representations of the numeric classes, computed by __repr__() and __str__(), have the following properties:

클래스 생성자에 전달될 때 원래 숫자 값을 가진 객체를 생성하는 유효한 숫자 리터럴 입니다.

가능하면, 표현은 10진법입니다.

소수점 앞의 단일 0을 제외하고, 선행 0은 표시되지 않습니다.

소수점 뒤의 단일 0을 제외하고, 후행 0은 표시되지 않습니다.

부호는 숫자가 음수일 때만 표시됩니다.

Python distinguishes between integers, floating-point numbers, and complex numbers:

3.2.4.1. numbers.Integral

이것들은 수학적인 정수 집합(양과 음)에 속하는 요소들을 나타냅니다.

참고

정수 표현 규칙은 음수가 포함된 시프트와 마스크 연산에 가장 의미 있는 해석을 제공하기 위한 것입니다.

두 가지 종류의 정수가 있습니다:

정수 (int)

이것은 (가상) 메모리가 허락하는 한, 제약 없는 범위의 숫자를 표현합니다. 시프트(shift)와 마스크(mask) 연산이 목적일 때는 이진 표현이 가정되고, 음수는 일종의 2의 보수(2’s complement)로 표현되는데, 부호 비트가 왼쪽으로 무한히 확장된 것과 같은 효과를 줍니다.

불린 (bool)

이것은 논리값 거짓과 참을 나타냅니다. False 와 True 두 객체만 불린 형 객체입니다. 불린 형은 int 형의 자식형(subtype)이고, 대부분 상황에서 각기 0과1처럼 동작합니다. 예외는 문자열로 변환되는 경우인데, 각기 문자열 "False" 와 "True" 가 반환됩니다.

3.2.4.2. numbers.Real (float)

These represent machine-level double precision floating-point numbers. You are at the mercy of the underlying machine architecture (and C or Java implementation) for the accepted range and handling of overflow. Python does not support single-precision floating-point numbers; the savings in processor and memory usage that are usually the reason for using these are dwarfed by the overhead of using objects in Python, so there is no reason to complicate the language with two kinds of floating-point numbers.

3.2.4.3. numbers.Complex (complex)

These represent complex numbers as a pair of machine-level double precision floating-point numbers. The same caveats apply as for floating-point numbers. The real and imaginary parts of a complex number z can be retrieved through the read-only attributes z.real and z.imag.

3.2.5. 시퀀스들

These represent finite ordered sets indexed by non-negative numbers. The built-in function len() returns the number of items of a sequence. When the length of a sequence is n, the index set contains the numbers 0, 1, …, n-1. Item i of sequence a is selected by a[i]. Some sequences, including built-in sequences, interpret negative subscripts by adding the sequence length. For example, a[-2] equals a[n-2], the second to last item of sequence a with length n.

Sequences also support slicing: a[i:j] selects all items with index k such that i <= k < j. When used as an expression, a slice is a sequence of the same type. The comment above about negative indexes also applies to negative slice positions.

어떤 시퀀스는 세 번째 “스텝(step)” 매개변수를 사용하는 “확장 슬라이싱(extended slicing)”도 지원합니다: a[i:j:k] 는 x = i + n*k, n >= 0, i <= x < j 를 만족하는 모든 항목 x 를 선택합니다.

시퀀스는 불변성에 따라 구분됩니다

3.2.5.1. 불변 시퀀스

불변 시퀀스 형의 객체는 일단 만들어진 후에는 변경될 수 없습니다. (만약 다른 객체로의 참조를 포함하면, 그 객체는 가변일 수 있고, 변경될 수 있습니다; 하지만, 불변 객체로부터 참조되는 객체의 집합 자체는 변경될 수 없습니다.)

다음과 같은 형들은 불변 시퀀스입니다:

문자열(Strings)

A string is a sequence of values that represent Unicode code points. All the code points in the range U+0000 - U+10FFFF can be represented in a string. Python doesn’t have a char type; instead, every code point in the string is represented as a string object with length 1. The built-in function ord() converts a code point from its string form to an integer in the range 0 - 10FFFF; chr() converts an integer in the range 0 - 10FFFF to the corresponding length 1 string object. str.encode() can be used to convert a str to bytes using the given text encoding, and bytes.decode() can be used to achieve the opposite.

튜플(Tuples)

튜플의 항목은 임의의 파이썬 객체입니다. 두 개 이상의 항목으로 구성되는 튜플은 콤마로 분리된 표현식의 목록으로 만들 수 있습니다. 하나의 항목으로 구성된 튜플(싱글턴,singleton)은 표현식에 콤마를 붙여서 만들 수 있습니다(괄호로 표현식을 묶을 수 있으므로, 표현식 만으로는 튜플을 만들지 않습니다). 빈 튜플은 한 쌍의 빈 괄호로 만들 수 있습니다.

바이트열(Bytes)

A bytes object is an immutable array. The items are 8-bit bytes, represented by integers in the range 0 <= x < 256. Bytes literals (like b'abc') and the built-in bytes() constructor can be used to create bytes objects. Also, bytes objects can be decoded to strings via the decode() method.

3.2.5.2. 가변 시퀀스

가변 시퀀스는 만들어진 후에 변경될 수 있습니다. 서브스크립션(subscription)과 슬라이싱은 대입문과 del (삭제) 문의 대상으로 사용될 수 있습니다.

참고

The collections and array module provide additional examples of mutable sequence types.

현재 두 개의 내장 가변 시퀀스형이 있습니다:

리스트(Lists)

리스트의 항목은 임의의 파이썬 객체입니다. 리스트는 콤마로 분리된 표현식을 대괄호 안에 넣어서 만들 수 있습니다. (길이 0이나 1의 리스트를 만드는데 별도의 규칙이 필요 없습니다.)

바이트 배열(Byte Arrays)

바이트 배열(bytearray) 객체는 가변 배열입니다. 내장 bytearray() 생성자로 만들어집니다. 가변이라는 것(그래서 해싱 불가능하다는 것)을 제외하고, 바이트 배열은 불변 바이트열( bytes) 객체와 같은 인터페이스와 기능을 제공합니다.

3.2.6. 집합 형들(Set types)

이것들은 중복 없는 불변 객체들의 순서 없고 유한한 집합을 나타냅니다. 인덱싱할 수 없습니다. 하지만 이터레이트할 수 있고, 내장 함수 len() 은 집합 안에 있는 항목들의 개수를 돌려줍니다. 집합의 일반적인 용도는 빠른 멤버십 검사(fast membership testing), 시퀀스에서 중복된 항목 제거, 교집합(intersection), 합집합(union), 차집합(difference), 대칭차집합(symmetric difference)과 같은 집합 연산을 계산하는 것입니다.

집합의 원소들에는 딕셔너리 키와 같은 불변성 규칙이 적용됩니다. 숫자 형의 경우는 숫자 비교에 관한 일반 원칙이 적용된다는 점에 주의해야 합니다: 만약 두 숫자가 같다고 비교되면(예를 들어, 1 과 1.0), 그중 하나만 집합에 들어갈 수 있습니다.

현재 두 개의 내장 집합 형이 있습니다:

집합(Sets)

이것들은 가변 집합을 나타냅니다. 내장 set() 생성자로 만들 수 있고, add() 같은 메서드들을 사용해서 나중에 수정할 수 있습니다.

불변 집합(Frozen sets)

이것들은 불변 집합을 나타냅니다. 내장 frozenset() 생성자로 만들 수 있습니다. 불변 집합(frozenset)은 불변이고 해시 가능 하므로, 다른 집합의 원소나, 딕셔너리의 키로 사용될 수 있습니다.

3.2.7. 매핑(Mappings)

이것들은 임의의 인덱스 집합으로 인덱싱되는 객체들의 유한한 집합을 나타냅니다. 인덱스 표기법(subscript notation) a[k] 는 매핑 a 에서 k 로 인덱스 되는 항목을 선택합니다; 이것은 표현식에 사용될 수도 있고, 대입이나 del 문장의 대상이 될 수도 있습니다. 내장 함수 len() 은 매핑에 포함된 항목들의 개수를 돌려줍니다.

현재 한 개의 내장 매핑 형이 있습니다:

3.2.7.1. 딕셔너리(Dictionaries)

이것들은 거의 임의의 인덱스 집합으로 인덱싱되는 객체들의 유한한 집합을 나타냅니다. 키로 사용할 수 없는 것들은 리스트, 딕셔너리나 그 외의 가변형 중에서 아이덴티티가 아니라 값으로 비교되는 것들뿐입니다. 딕셔너리의 효율적인 구현이, 키의 해시값이 도중에 변경되지 않고 계속 같은 값으로 유지되도록 요구하고 있기 때문입니다. 키로 사용되는 숫자 형의 경우는 숫자 비교에 관한 일반 원칙이 적용됩니다: 만약 두 숫자가 같다고 비교되면(예를 들어, 1 과 1.0), 둘 다 같은 딕셔너리 항목을 인덱싱하는데 사용될 수 있습니다.

딕셔너리는 삽입 순서를 유지합니다, 키가 딕셔너리에 순차적으로 추가된 순서와 같은 순서로 생성됨을 뜻합니다. 기존 키를 교체해도 순서는 변경되지 않지만, 키를 제거했다가 다시 삽입하면 이전 위치를 유지하는 대신 끝에 추가됩니다.

Dictionaries are mutable; they can be created by the {} notation (see section 딕셔너리 디스플레이).

확장 모듈 dbm.ndbm 과 dbm.gnu 는 추가의 매핑 형을 제공하는데, collections 모듈 역시 마찬가지입니다.

버전 3.7에서 변경: 딕셔너리는 3.6 이전의 파이썬 버전에서 삽입 순서를 유지하지 않았습니다. CPython 3.6에서, 삽입 순서가 유지되었지만, 그 시점에는 언어 보증이 아니라 구현 세부 사항으로 간주하였습니다.

3.2.8. 콜러블(Callable types)

이것들은 함수 호출 연산(호출 섹션 참고)이 적용될 수 있는 형들입니다:

3.2.8.1. 사용자 정의 함수

사용자 정의 함수 객체는 함수 정의를 통해 만들어집니다 (함수 정의 섹션 참고). 함수의 형식 매개변수(formal parameter) 목록과 같은 개수의 항목을 포함하는 인자(argument) 목록으로 호출되어야 합니다.

3.2.8.1.1. Special read-only attributes

어트리뷰트

의미

function.__globals__

A reference to the dictionary that holds the function’s global variables – the global namespace of the module in which the function was defined.

function.__closure__

None or a tuple of cells that contain bindings for the names specified in the co_freevars attribute of the function’s code object.

셀 객체는 cell_contents 어트리뷰트를 가지고 있습니다. 셀의 값을 읽을 뿐만 아니라 값을 설정하는 데도 사용할 수 있습니다.

3.2.8.1.2. Special writable attributes

Most of these attributes check the type of the assigned value:

어트리뷰트

의미

function.__doc__

The function’s documentation string, or None if unavailable.

function.__name__

The function’s name. See also: __name__ attributes.

function.__qualname__

The function’s qualified name. See also: __qualname__ attributes.

Added in version 3.3.

function.__module__

함수가 정의된 모듈의 이름 또는 (없는 경우) None

function.__defaults__

A tuple containing default parameter values for those parameters that have defaults, or None if no parameters have a default value.

function.__code__

The code object representing the compiled function body.

function.__dict__

The namespace supporting arbitrary function attributes. See also: __dict__ attributes.

function.__annotations__

A dictionary containing annotations of parameters. The keys of the dictionary are the parameter names, and 'return' for the return annotation, if provided. See also: object.__annotations__.

버전 3.14에서 변경: Annotations are now lazily evaluated. See PEP 649 [https://peps.python.org/pep-0649/].

function.__annotate__

The annotate function for this function, or None if the function has no annotations. See object.__annotate__.

Added in version 3.14.

function.__kwdefaults__

A dictionary containing defaults for keyword-only parameters.

function.__type_params__

A tuple containing the type parameters of a generic function.

Added in version 3.12.

Function objects also support getting and setting arbitrary attributes, which can be used, for example, to attach metadata to functions. Regular attribute dot-notation is used to get and set such attributes.

CPython 구현 상세: CPython’s current implementation only supports function attributes on user-defined functions. Function attributes on built-in functions may be supported in the future.

Additional information about a function’s definition can be retrieved from its code object (accessible via the __code__ attribute).

3.2.8.2. 인스턴스 메서드(Instance methods)

인스턴스 메서드는 클래스, 클래스 인스턴스와 모든 콜러블 객체 (보통 사용자 정의 함수)을 결합합니다.

Special read-only attributes:

method.__self__

Refers to the class instance object to which the method is bound

method.__func__

Refers to the original function object

method.__doc__

The method’s documentation (same as method.__func__.__doc__). A string if the original function had a docstring, else None.

method.__name__

The name of the method (same as method.__func__.__name__)

method.__module__

The name of the module the method was defined in, or None if unavailable.

Methods also support accessing (but not setting) the arbitrary function attributes on the underlying function object.

User-defined method objects may be created when getting an attribute of a class (perhaps via an instance of that class), if that attribute is a user-defined function object or a classmethod object.

When an instance method object is created by retrieving a user-defined function object from a class via one of its instances, its __self__ attribute is the instance, and the method object is said to be bound. The new method’s __func__ attribute is the original function object.

When an instance method object is created by retrieving a classmethod object from a class or instance, its __self__ attribute is the class itself, and its __func__ attribute is the function object underlying the class method.

When an instance method object is called, the underlying function (__func__) is called, inserting the class instance (__self__) in front of the argument list. For instance, when C is a class which contains a definition for a function f(), and x is an instance of C, calling x.f(1) is equivalent to calling C.f(x, 1).

When an instance method object is derived from a classmethod object, the “class instance” stored in __self__ will actually be the class itself, so that calling either x.f(1) or C.f(1) is equivalent to calling f(C,1) where f is the underlying function.

It is important to note that user-defined functions which are attributes of a class instance are not converted to bound methods; this only happens when the function is an attribute of the class.

3.2.8.3. 제너레이터 함수(Generator functions)

A function or method which uses the yield statement (see section yield 문) is called a generator function. Such a function, when called, always returns an iterator object which can be used to execute the body of the function: calling the iterator’s iterator.__next__() method will cause the function to execute until it provides a value using the yield statement. When the function executes a return statement or falls off the end, a StopIteration exception is raised and the iterator will have reached the end of the set of values to be returned.

3.2.8.4. 코루틴 함수(Coroutine functions)

async def 를 사용해서 정의되는 함수나 메서드를 코루틴 함수 (coroutine function) 라고 부릅니다. 이런 함수를 호출하면 코루틴 객체를 돌려줍니다. await 표현식을 비롯해, async with 와 async for 문을 사용할 수 있습니다. 코루틴 객체(Coroutine Objects) 섹션을 참조하십시오.

3.2.8.5. 비동기 제너레이터 함수(Asynchronous generator functions)

A function or method which is defined using async def and which uses the yield statement is called a asynchronous generator function. Such a function, when called, returns an asynchronous iterator object which can be used in an async for statement to execute the body of the function.

Calling the asynchronous iterator’s aiterator.__anext__ method will return an awaitable which when awaited will execute until it provides a value using the yield expression. When the function executes an empty return statement or falls off the end, a StopAsyncIteration exception is raised and the asynchronous iterator will have reached the end of the set of values to be yielded.

3.2.8.6. 내장 함수(Built-in functions)

A built-in function object is a wrapper around a C function. Examples of built-in functions are len() and math.sin() (math is a standard built-in module). The number and type of the arguments are determined by the C function. Special read-only attributes:

__doc__ is the function’s documentation string, or None if unavailable. See function.__doc__.

__name__ is the function’s name. See function.__name__.

__self__ is set to None (but see the next item).

__module__ is the name of the module the function was defined in or None if unavailable. See function.__module__.

3.2.8.7. 내장 메서드(Built-in methods)

This is really a different disguise of a built-in function, this time containing an object passed to the C function as an implicit extra argument. An example of a built-in method is alist.append(), assuming alist is a list object. In this case, the special read-only attribute __self__ is set to the object denoted by alist. (The attribute has the same semantics as it does with other instance methods.)

3.2.8.8. 클래스(Classes)

Classes are callable. These objects normally act as factories for new instances of themselves, but variations are possible for class types that override __new__(). The arguments of the call are passed to __new__() and, in the typical case, to __init__() to initialize the new instance.

3.2.8.9. 클래스 인스턴스(Class Instances)

Instances of arbitrary classes can be made callable by defining a __call__() method in their class.

3.2.9. 모듈(Modules)

Modules are a basic organizational unit of Python code, and are created by the import system as invoked either by the import statement, or by calling functions such as importlib.import_module() and built-in __import__(). A module object has a namespace implemented by a dictionary object (this is the dictionary referenced by the __globals__ attribute of functions defined in the module). Attribute references are translated to lookups in this dictionary, e.g., m.x is equivalent to m.__dict__["x"]. A module object does not contain the code object used to initialize the module (since it isn’t needed once the initialization is done).

어트리뷰트 대입은 모듈의 이름 공간 딕셔너리를 갱신합니다. 예를 들어, m.x = 1 은 m.__dict__["x"] = 1 과 같습니다.

3.2.9.1. Import-related attributes on module objects

Module objects have the following attributes that relate to the import system. When a module is created using the machinery associated with the import system, these attributes are filled in based on the module’s spec, before the loader executes and loads the module.

To create a module dynamically rather than using the import system, it’s recommended to use importlib.util.module_from_spec(), which will set the various import-controlled attributes to appropriate values. It’s also possible to use the types.ModuleType constructor to create modules directly, but this technique is more error-prone, as most attributes must be manually set on the module object after it has been created when using this approach.

조심

With the exception of __name__, it is strongly recommended that you rely on __spec__ and its attributes instead of any of the other individual attributes listed in this subsection. Note that updating an attribute on __spec__ will not update the corresponding attribute on the module itself:

>>> import typing
>>> typing.__name__, typing.__spec__.name
('typing', 'typing')
>>> typing.__spec__.name = 'spelling'
>>> typing.__name__, typing.__spec__.name
('typing', 'spelling')
>>> typing.__name__ = 'keyboard_smashing'
>>> typing.__name__, typing.__spec__.name
('keyboard_smashing', 'spelling')

module.__name__

The name used to uniquely identify the module in the import system. For a directly executed module, this will be set to "__main__".

This attribute must be set to the fully qualified name of the module. It is expected to match the value of module.__spec__.name.

module.__spec__

A record of the module’s import-system-related state.

Set to the module spec that was used when importing the module. See Module specs for more details.

Added in version 3.4.

module.__package__

The package a module belongs to.

If the module is top-level (that is, not a part of any specific package) then the attribute should be set to '' (the empty string). Otherwise, it should be set to the name of the module’s package (which can be equal to module.__name__ if the module itself is a package). See PEP 366 [https://peps.python.org/pep-0366/] for further details.

This attribute is used instead of __name__ to calculate explicit relative imports for main modules. It defaults to None for modules created dynamically using the types.ModuleType constructor; use importlib.util.module_from_spec() instead to ensure the attribute is set to a str.

It is strongly recommended that you use module.__spec__.parent instead of module.__package__. __package__ is now only used as a fallback if __spec__.parent is not set, and this fallback path is deprecated.

버전 3.4에서 변경: This attribute now defaults to None for modules created dynamically using the types.ModuleType constructor. Previously the attribute was optional.

버전 3.6에서 변경: The value of __package__ is expected to be the same as __spec__.parent. __package__ is now only used as a fallback during import resolution if __spec__.parent is not defined.

버전 3.10에서 변경: ImportWarning is raised if an import resolution falls back to __package__ instead of __spec__.parent.

버전 3.12에서 변경: Raise DeprecationWarning instead of ImportWarning when falling back to __package__ during import resolution.

Deprecated since version 3.13, will be removed in version 3.15: __package__ will cease to be set or taken into consideration by the import system or standard library.

module.__loader__

The loader object that the import machinery used to load the module.

This attribute is mostly useful for introspection, but can be used for additional loader-specific functionality, for example getting data associated with a loader.

__loader__ defaults to None for modules created dynamically using the types.ModuleType constructor; use importlib.util.module_from_spec() instead to ensure the attribute is set to a loader object.

It is strongly recommended that you use module.__spec__.loader instead of module.__loader__.

버전 3.4에서 변경: This attribute now defaults to None for modules created dynamically using the types.ModuleType constructor. Previously the attribute was optional.

Deprecated since version 3.12, will be removed in version 3.16: Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

module.__path__

A (possibly empty) sequence of strings enumerating the locations where the package’s submodules will be found. Non-package modules should not have a __path__ attribute. See __path__ attributes on modules for more details.

It is strongly recommended that you use module.__spec__.submodule_search_locations instead of module.__path__.

module.__file__

module.__cached__

__file__ and __cached__ are both optional attributes that may or may not be set. Both attributes should be a str when they are available.

__file__ indicates the pathname of the file from which the module was loaded (if loaded from a file), or the pathname of the shared library file for extension modules loaded dynamically from a shared library. It might be missing for certain types of modules, such as C modules that are statically linked into the interpreter, and the import system may opt to leave it unset if it has no semantic meaning (for example, a module loaded from a database).

If __file__ is set then the __cached__ attribute might also be set, which is the path to any compiled version of the code (for example, a byte-compiled file). The file does not need to exist to set this attribute; the path can simply point to where the compiled file would exist (see PEP 3147 [https://peps.python.org/pep-3147/]).

Note that __cached__ may be set even if __file__ is not set. However, that scenario is quite atypical. Ultimately, the loader is what makes use of the module spec provided by the finder (from which __file__ and __cached__ are derived). So if a loader can load from a cached module but otherwise does not load from a file, that atypical scenario may be appropriate.

It is strongly recommended that you use module.__spec__.cached instead of module.__cached__.

Deprecated since version 3.13, will be removed in version 3.15: Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or taken into consideration by the import system or standard library.

3.2.9.2. Other writable attributes on module objects

As well as the import-related attributes listed above, module objects also have the following writable attributes:

module.__doc__

The module’s documentation string, or None if unavailable. See also: __doc__ attributes.

module.__annotations__

A dictionary containing variable annotations collected during module body execution. For best practices on working with __annotations__, see annotationlib.

버전 3.14에서 변경: Annotations are now lazily evaluated. See PEP 649 [https://peps.python.org/pep-0649/].

module.__annotate__

The annotate function for this module, or None if the module has no annotations. See also: __annotate__ attributes.

Added in version 3.14.

3.2.9.3. Module dictionaries

Module objects also have the following special read-only attribute:

module.__dict__

The module’s namespace as a dictionary object. Uniquely among the attributes listed here, __dict__ cannot be accessed as a global variable from within a module; it can only be accessed as an attribute on module objects.

CPython 구현 상세: CPython 이 모듈 딕셔너리를 비우는 방법 때문에, 딕셔너리에 대한 참조가 남아있더라도, 모듈이 스코프를 벗어나면 모듈 딕셔너리는 비워집니다. 이것을 피하려면, 딕셔너리를 복사하거나 딕셔너리를 직접 이용하는 동안은 모듈을 잡아두어야 합니다.

3.2.10. 사용자 정의 클래스(Custom classes)

Custom class types are typically created by class definitions (see section 클래스 정의). A class has a namespace implemented by a dictionary object. Class attribute references are translated to lookups in this dictionary, e.g., C.x is translated to C.__dict__["x"] (although there are a number of hooks which allow for other means of locating attributes). When the attribute name is not found there, the attribute search continues in the base classes. This search of the base classes uses the C3 method resolution order which behaves correctly even in the presence of ‘diamond’ inheritance structures where there are multiple inheritance paths leading back to a common ancestor. Additional details on the C3 MRO used by Python can be found at The Python 2.3 Method Resolution Order.

When a class attribute reference (for class C, say) would yield a class method object, it is transformed into an instance method object whose __self__ attribute is C. When it would yield a staticmethod object, it is transformed into the object wrapped by the static method object. See section 디스크립터 구현하기 for another way in which attributes retrieved from a class may differ from those actually contained in its __dict__.

클래스 어트리뷰트 대입은 클래스의 딕셔너리를 갱신할 뿐, 어떤 경우도 부모 클래스의 딕셔너리를 건드리지는 않습니다.

클래스 객체는 클래스 인스턴스를 돌려주도록(아래를 보십시오) 호출될 수 있습니다(위를 보십시오).

3.2.10.1. Special attributes

어트리뷰트

의미

type.__name__

The class’s name. See also: __name__ attributes.

type.__qualname__

The class’s qualified name. See also: __qualname__ attributes.

type.__module__

The name of the module in which the class was defined.

type.__dict__

A mapping proxy providing a read-only view of the class’s namespace. See also: __dict__ attributes.

type.__bases__

A tuple containing the class’s bases. In most cases, for a class defined as class X(A, B, C), X.__bases__ will be exactly equal to (A, B, C).

type.__doc__

The class’s documentation string, or None if undefined. Not inherited by subclasses.

type.__annotations__

A dictionary containing variable annotations collected during class body execution. See also: __annotations__ attributes.

For best practices on working with __annotations__, please see annotationlib.

조심

Accessing the __annotations__ attribute of a class object directly may yield incorrect results in the presence of metaclasses. In addition, the attribute may not exist for some classes. Use annotationlib.get_annotations() to retrieve class annotations safely.

버전 3.14에서 변경: Annotations are now lazily evaluated. See PEP 649 [https://peps.python.org/pep-0649/].

type.__annotate__()

The annotate function for this class, or None if the class has no annotations. See also: __annotate__ attributes.

조심

Accessing the __annotate__ attribute of a class object directly may yield incorrect results in the presence of metaclasses. Use annotationlib.get_annotate_function() to retrieve the annotate function safely.

Added in version 3.14.

type.__type_params__

A tuple containing the type parameters of a generic class.

Added in version 3.12.

type.__static_attributes__

A tuple containing names of attributes of this class which are assigned through self.X from any function in its body.

Added in version 3.13.

type.__firstlineno__

The line number of the first line of the class definition, including decorators. Setting the __module__ attribute removes the __firstlineno__ item from the type’s dictionary.

Added in version 3.13.

type.__mro__

The tuple of classes that are considered when looking for base classes during method resolution.

3.2.10.2. Special methods

In addition to the special attributes described above, all Python classes also have the following two methods available:

type.mro()

This method can be overridden by a metaclass to customize the method resolution order for its instances. It is called at class instantiation, and its result is stored in __mro__.

type.__subclasses__()

Each class keeps a list of weak references to its immediate subclasses. This method returns a list of all those references still alive. The list is in definition order. Example:

>>> class A: pass
>>> class B(A): pass
>>> A.__subclasses__()
[<class 'B'>]

3.2.11. 클래스 인스턴스(Class instances)

A class instance is created by calling a class object (see above). A class instance has a namespace implemented as a dictionary which is the first place in which attribute references are searched. When an attribute is not found there, and the instance’s class has an attribute by that name, the search continues with the class attributes. If a class attribute is found that is a user-defined function object, it is transformed into an instance method object whose __self__ attribute is the instance. Static method and class method objects are also transformed; see above under “Classes”. See section 디스크립터 구현하기 for another way in which attributes of a class retrieved via its instances may differ from the objects actually stored in the class’s __dict__. If no class attribute is found, and the object’s class has a __getattr__() method, that is called to satisfy the lookup.

Attribute assignments and deletions update the instance’s dictionary, never a class’s dictionary. If the class has a __setattr__() or __delattr__() method, this is called instead of updating the instance dictionary directly.

어떤 특별한 이름들의 메서드들을 가지면, 클래스 인스턴스는 숫자, 시퀀스, 매핑인 척할 수 있습니다. 특수 메서드 이름들 섹션을 보십시오.

3.2.11.1. Special attributes

object.__class__

The class to which a class instance belongs.

object.__dict__

A dictionary or other mapping object used to store an object’s (writable) attributes. Not all instances have a __dict__ attribute; see the section on __slots__ for more details.

3.2.12. I/O 객체 (파일 객체라고도 알려져 있습니다)

파일 객체 는 열린 파일을 나타냅니다. 파일 객체를 만드는 여러 가지 단축법이 있습니다: open() 내장 함수, os.popen(), os.fdopen() 과 소켓 객체의 makefile() 메서드 (그리고, 아마도 확장 모듈들이 제공하는 다른 함수들이나 메서드들).

sys.stdin, sys.stdout, sys.stderr 는 인터프리터의 표준 입력, 출력, 에러 스트림으로 초기화된 파일 객체들입니다; 모두 텍스트 모드로 열려서 io.TextIOBase 추상 클래스에 의해 정의된 인터페이스를 따릅니다.

3.2.13. 내부 형(Internal types)

인터프리터가 내부적으로 사용하는 몇몇 형들은 사용자에게 노출됩니다. 인터프리터의 미래 버전에서 이들의 정의는 변경될 수 있지만, 완전함을 위해 여기서 언급합니다.

3.2.13.1. 코드 객체(Code objects)

코드 객체는 바이트로 컴파일된(byte-compiled) 실행 가능한 파이썬 코드를 나타내는데, 그냥 바이트 코드 라고도 부릅니다. 코드 객체와 함수 객체 간에는 차이가 있습니다; 함수 객체는 함수의 전역 공간(globals) (함수가 정의된 모듈)을 명시적으로 참조하고 있지만, 코드 객체는 어떤 문맥(context)도 갖고 있지 않습니다; 또한 기본 인자값들이 함수 객체에 저장되어 있지만 코드 객체에는 들어있지 않습니다 (실행 시간에 계산되는 값들을 나타내기 때문입니다). 함수 객체와는 달리, 코드 객체는 불변이고 가변 객체들에 대한 어떤 참조도 (직접 혹은 간접적으로도) 갖고 있지 않습니다.

3.2.13.1.1. Special read-only attributes

codeobject.co_name

The function name

codeobject.co_qualname

The fully qualified function name

Added in version 3.11.

codeobject.co_argcount

The total number of positional parameters (including positional-only parameters and parameters with default values) that the function has

codeobject.co_posonlyargcount

The number of positional-only parameters (including arguments with default values) that the function has

codeobject.co_kwonlyargcount

The number of keyword-only parameters (including arguments with default values) that the function has

codeobject.co_nlocals

The number of local variables used by the function (including parameters)

codeobject.co_varnames

A tuple containing the names of the local variables in the function (starting with the parameter names)

codeobject.co_cellvars

A tuple containing the names of local variables that are referenced from at least one nested scope inside the function

codeobject.co_freevars

A tuple containing the names of free (closure) variables that a nested scope references in an outer scope. See also function.__closure__.

Note: references to global and builtin names are not included.

codeobject.co_code

A string representing the sequence of bytecode instructions in the function

codeobject.co_consts

A tuple containing the literals used by the bytecode in the function

codeobject.co_names

A tuple containing the names used by the bytecode in the function

codeobject.co_filename

The name of the file from which the code was compiled

codeobject.co_firstlineno

The line number of the first line of the function

codeobject.co_lnotab

A string encoding the mapping from bytecode offsets to line numbers. For details, see the source code of the interpreter.

버전 3.12부터 폐지됨: This attribute of code objects is deprecated, and may be removed in Python 3.15.

codeobject.co_stacksize

The required stack size of the code object

codeobject.co_flags

An integer encoding a number of flags for the interpreter.

The following flag bits are defined for co_flags: bit 0x04 is set if the function uses the *arguments syntax to accept an arbitrary number of positional arguments; bit 0x08 is set if the function uses the **keywords syntax to accept arbitrary keyword arguments; bit 0x20 is set if the function is a generator. See 코드 객체 비트 플래그 for details on the semantics of each flags that might be present.

Future feature declarations (from __future__ import division) also use bits in co_flags to indicate whether a code object was compiled with a particular feature enabled: bit 0x2000 is set if the function was compiled with future division enabled; bits 0x10 and 0x1000 were used in earlier versions of Python.

Other bits in co_flags are reserved for internal use.

If a code object represents a function and has a docstring, the first item in co_consts is the docstring of the function.

3.2.13.1.2. Methods on code objects

codeobject.co_positions()

Returns an iterable over the source code positions of each bytecode instruction in the code object.

The iterator returns tuples containing the (start_line, end_line, start_column, end_column). The i-th tuple corresponds to the position of the source code that compiled to the i-th code unit. Column information is 0-indexed utf-8 byte offsets on the given source line.

This positional information can be missing. A non-exhaustive lists of cases where this may happen:

Running the interpreter with -X no_debug_ranges.

Loading a pyc file compiled while using -X no_debug_ranges.

Position tuples corresponding to artificial instructions.

Line and column numbers that can’t be represented due to implementation specific limitations.

When this occurs, some or all of the tuple elements can be None.

Added in version 3.11.

참고

This feature requires storing column positions in code objects which may result in a small increase of disk usage of compiled Python files or interpreter memory usage. To avoid storing the extra information and/or deactivate printing the extra traceback information, the -X no_debug_ranges command line flag or the PYTHONNODEBUGRANGES environment variable can be used.

codeobject.co_lines()

Returns an iterator that yields information about successive ranges of bytecodes. Each item yielded is a (start, end, lineno) tuple:

start (an int) represents the offset (inclusive) of the start of the bytecode range

end (an int) represents the offset (exclusive) of the end of the bytecode range

lineno is an int representing the line number of the bytecode range, or None if the bytecodes in the given range have no line number

The items yielded will have the following properties:

The first range yielded will have a start of 0.

The (start, end) ranges will be non-decreasing and consecutive. That is, for any pair of tuples, the start of the second will be equal to the end of the first.

No range will be backwards: end >= start for all triples.

The last tuple yielded will have end equal to the size of the bytecode.

Zero-width ranges, where start == end, are allowed. Zero-width ranges are used for lines that are present in the source code, but have been eliminated by the bytecode compiler.

Added in version 3.10.

더 보기

PEP 626 [https://peps.python.org/pep-0626/] - Precise line numbers for debugging and other tools.

The PEP that introduced the co_lines() method.

codeobject.replace(**kwargs)

Return a copy of the code object with new values for the specified fields.

Code objects are also supported by the generic function copy.replace().

Added in version 3.8.

3.2.13.2. 프레임 객체(Frame objects)

Frame objects represent execution frames. They may occur in traceback objects, and are also passed to registered trace functions.

3.2.13.2.1. Special read-only attributes

frame.f_back

Points to the previous stack frame (towards the caller), or None if this is the bottom stack frame

frame.f_code

The code object being executed in this frame. Accessing this attribute raises an auditing event object.__getattr__ with arguments obj and "f_code".

frame.f_locals

The mapping used by the frame to look up local variables. If the frame refers to an optimized scope, this may return a write-through proxy object.

버전 3.13에서 변경: Return a proxy for optimized scopes.

frame.f_globals

The dictionary used by the frame to look up global variables

frame.f_builtins

The dictionary used by the frame to look up built-in (intrinsic) names

frame.f_lasti

The “precise instruction” of the frame object (this is an index into the bytecode string of the code object)

3.2.13.2.2. Special writable attributes

frame.f_trace

If not None, this is a function called for various events during code execution (this is used by debuggers). Normally an event is triggered for each new source line (see f_trace_lines).

frame.f_trace_lines

Set this attribute to False to disable triggering a tracing event for each source line.

frame.f_trace_opcodes

Set this attribute to True to allow per-opcode events to be requested. Note that this may lead to undefined interpreter behaviour if exceptions raised by the trace function escape to the function being traced.

frame.f_lineno

The current line number of the frame – writing to this from within a trace function jumps to the given line (only for the bottom-most frame). A debugger can implement a Jump command (aka Set Next Statement) by writing to this attribute.

3.2.13.2.3. Frame object methods

프레임 객체는 한가지 메서드를 지원합니다:

frame.clear()

This method clears all references to local variables held by the frame. Also, if the frame belonged to a generator, the generator is finalized. This helps break reference cycles involving frame objects (for example when catching an exception and storing its traceback for later use).

RuntimeError is raised if the frame is currently executing or suspended.

Added in version 3.4.

버전 3.13에서 변경: Attempting to clear a suspended frame raises RuntimeError (as has always been the case for executing frames).

3.2.13.3. 트레이스백 객체(Traceback objects)

Traceback objects represent the stack trace of an exception. A traceback object is implicitly created when an exception occurs, and may also be explicitly created by calling types.TracebackType.

버전 3.7에서 변경: Traceback objects can now be explicitly instantiated from Python code.

For implicitly created tracebacks, when the search for an exception handler unwinds the execution stack, at each unwound level a traceback object is inserted in front of the current traceback. When an exception handler is entered, the stack trace is made available to the program. (See section try 문.) It is accessible as the third item of the tuple returned by sys.exc_info(), and as the __traceback__ attribute of the caught exception.

When the program contains no suitable handler, the stack trace is written (nicely formatted) to the standard error stream; if the interpreter is interactive, it is also made available to the user as sys.last_traceback.

For explicitly created tracebacks, it is up to the creator of the traceback to determine how the tb_next attributes should be linked to form a full stack trace.

Special read-only attributes:

traceback.tb_frame

Points to the execution frame of the current level.

Accessing this attribute raises an auditing event object.__getattr__ with arguments obj and "tb_frame".

traceback.tb_lineno

Gives the line number where the exception occurred

traceback.tb_lasti

Indicates the “precise instruction”.

The line number and last instruction in the traceback may differ from the line number of its frame object if the exception occurred in a try statement with no matching except clause or with a finally clause.

traceback.tb_next

The special writable attribute tb_next is the next level in the stack trace (towards the frame where the exception occurred), or None if there is no next level.

버전 3.7에서 변경: This attribute is now writable

3.2.13.4. 슬라이스 객체(Slice objects)

Slice objects are used to represent slices for __getitem__() methods. They are also created by the built-in slice() function.

특수 읽기 전용 어트리뷰트들: start 는 하한(lower bound) 입니다; stop 은 상한(upper bound) 입니다; step 은 스텝 값입니다; 각 값은 생략될 경우 None 입니다. 이 어트리뷰트들은 임의의 형이 될 수 있습니다.

슬라이스 객체는 하나의 메서드를 지원합니다.

slice.indices(self, length)

이 메서드는 하나의 정수 인자 length 를 받아서 슬라이스 객체가 길이 length 인 시퀀스에 적용되었을 때 그 슬라이스에 대한 정보를 계산합니다. 세 개의 정수로 구성된 튜플을 돌려줍니다: 이것들은 각각 start 와 stop 인덱스와, step 또는 슬라이스의 스트라이드(stride) 길이입니다. 생략되었거나 범위를 벗어난 인덱스들은 일반적인 슬라이스와 같은 방법으로 다뤄집니다.

3.2.13.5. 스태틱 메서드 객체(Static method objects)

Static method objects provide a way of defeating the transformation of function objects to method objects described above. A static method object is a wrapper around any other object, usually a user-defined method object. When a static method object is retrieved from a class or a class instance, the object actually returned is the wrapped object, which is not subject to any further transformation. Static method objects are also callable. Static method objects are created by the built-in staticmethod() constructor.

3.2.13.6. 클래스 메서드 객체(Class method objects)

A class method object, like a static method object, is a wrapper around another object that alters the way in which that object is retrieved from classes and class instances. The behaviour of class method objects upon such retrieval is described above, under “instance methods”. Class method objects are created by the built-in classmethod() constructor.

3.3. 특수 메서드 이름들

A class can implement certain operations that are invoked by special syntax (such as arithmetic operations or subscripting and slicing) by defining methods with special names. This is Python’s approach to operator overloading, allowing classes to define their own behavior with respect to language operators. For instance, if a class defines a method named __getitem__(), and x is an instance of this class, then x[i] is roughly equivalent to type(x).__getitem__(x, i). Except where mentioned, attempts to execute an operation raise an exception when no appropriate method is defined (typically AttributeError or TypeError).

Setting a special method to None indicates that the corresponding operation is not available. For example, if a class sets __iter__() to None, the class is not iterable, so calling iter() on its instances will raise a TypeError (without falling back to __getitem__()). [2]

내장형을 흉내 내는 클래스를 구현할 때, 모방은 모형화하는 객체에 말이 되는 수준까지만 구현하는 것이 중요합니다. 예를 들어, 어떤 시퀀스는 개별 항목들을 꺼내는 것만으로도 잘 동작할 수 있습니다. 하지만 슬라이스를 꺼내는 것은 말이 안 될 수 있습니다. (이런 한가지 예는 W3C의 Document Object Model의 NodeList 인터페이스입니다.)

3.3.1. 기본적인 커스터마이제이션

object.__new__(cls[, ...])

클래스 cls 의 새 인스턴스를 만들기 위해 호출됩니다. __new__() 는 스태틱 메서드입니다 (그렇게 선언하지 않아도 되는 특별한 경우입니다)인데, 첫 번째 인자로 만들려고 하는 인스턴스의 클래스가 전달됩니다. 나머지 인자들은 객체 생성자 표현(클래스 호출)에 전달된 것들입니다. __new__() 의 반환 값은 새 객체 인스턴스이어야 합니다 (보통 cls 의 인스턴스).

Typical implementations create a new instance of the class by invoking the superclass’s __new__() method using super().__new__(cls[, ...]) with appropriate arguments and then modifying the newly created instance as necessary before returning it.

If __new__() is invoked during object construction and it returns an instance of cls, then the new instance’s __init__() method will be invoked like __init__(self[, ...]), where self is the new instance and the remaining arguments are the same as were passed to the object constructor.

만약 __new__() 가 cls 의 인스턴스를 돌려주지 않으면, 새 인스턴스의 __init__() 는 호출되지 않습니다.

__new__() 는 주로 불변형(int, str, tuple과 같은)의 서브 클래스가 인스턴스 생성을 커스터마이즈할 수 있도록 하는 데 사용됩니다. 또한, 사용자 정의 메타 클래스에서 클래스 생성을 커스터마이즈하기 위해 자주 사용됩니다.

object.__init__(self[, ...])

(__new__() 에 의해) 인스턴스가 만들어진 후에, 하지만 호출자에게 돌려주기 전에 호출됩니다. 인자들은 클래스 생성자 표현으로 전달된 것들입니다. 만약 베이스 클래스가 __init__() 메서드를 갖고 있다면, 서브 클래스의 __init__() 메서드는, 있다면, 인스턴스에서 베이스 클래스가 차지하는 부분이 올바르게 초기화됨을 확실히 하기 위해 명시적으로 호출해주어야 합니다; 예를 들어: super().__init__([args...]).

객체를 만드는데 __new__() 와 __init__() 가 협력하고 있으므로 (__new__() 는 만들고, __init__() 는 그것을 커스터마이즈합니다), __init__() 가 None 이외의 값을 돌려주면 실행시간에 TypeError 를 일으킵니다.

object.__del__(self)

인스턴스가 파괴되기 직전에 호출됩니다. 파이널라이저 또는 (부적절하게) 파괴자라고 불립니다. 만약 베이스 클래스가 __del__() 메서드를 갖고 있다면, 자식 클래스의 __del__() 메서드는, 정의되어 있다면, 인스턴스에서 베이스 클래스가 차지하는 부분을 적절하게 삭제하기 위해, 명시적으로 베이스 클래스의 메서드를 호출해야 합니다.

(권장하지는 않지만!) __del__() 메서드는 인스턴스에 대한 새로운 참조를 만듦으로써 인스턴스의 파괴를 지연시킬 수 있습니다. 이것을 객체 부활 이라고 부릅니다. 부활한 객체가 파괴될 때 __del__() 이 두 번째로 호출될지는 구현에 따라 다릅니다; 현재 CPython 구현은 오직 한 번만 호출합니다.

It is not guaranteed that __del__() methods are called for objects that still exist when the interpreter exits. weakref.finalize provides a straightforward way to register a cleanup function to be called when an object is garbage collected.

참고

del x 는 직접 x.__del__() 를 호출하지 않습니다 — 앞에 있는 것은 x 의 참조 횟수(reference count)를 하나 감소시키고, 뒤에 있는 것은 x 의 참조 횟수가 0 이 될 때 호출됩니다.

CPython 구현 상세: It is possible for a reference cycle to prevent the reference count of an object from going to zero. In this case, the cycle will be later detected and deleted by the cyclic garbage collector. A common cause of reference cycles is when an exception has been caught in a local variable. The frame’s locals then reference the exception, which references its own traceback, which references the locals of all frames caught in the traceback.

더 보기

gc 모듈에 대한 문서.

경고

__del__() 이 호출되는 불안정한 상황 때문에, 이것이 실행 중에 발생시키는 예외는 무시되고, 대신에 sys.stderr 로 경고가 출력됩니다. 특히:

__del__() 은 (임의의 스레드에서) 임의의 코드가 실행되는 동안 호출될 수 있습니다. __del__() 이 록을 얻어야 하거나 다른 블로킹 자원을 호출하면, __del__() 을 실행하기 위해 중단된 코드가 자원을 이미 차지했을 수 있으므로 교착 상태에 빠질 수 있습니다.

__del__() 은 인터프리터를 종료할 때 실행될 수 있습니다. 결과적으로, 액세스해야 하는 전역 변수(다른 모듈 포함)가 이미 삭제되었거나 None 으로 설정되었을 수 있습니다. 파이썬은 이름이 하나의 밑줄로 시작하는 전역 객체가 다른 전역 객체들보다 먼저 삭제됨을 보장합니다; 이것은, 만약 그 전역 객체들에 대한 다른 참조가 존재하지 않는다면, __del__() 메서드가 호출되는 시점에, 임포트된 모듈들이 남아있도록 확실히 하는 데 도움이 될 수 있습니다.

object.__repr__(self)

repr() 내장 함수에 의해 호출되어 객체의 “형식적인(official)” 문자열 표현을 계산합니다. 만약 가능하다면, 이것은 같은 (적절한 환경이 주어질 때) 값을 갖는 객체를 새로 만들 수 있는 올바른 파이썬 표현식처럼 보여야 합니다. 가능하지 않다면, <...쓸모있는 설명...> 형태의 문자열을 돌려줘야 합니다. 반환 값은 반드시 문자열이어야 합니다. 만약 클래스가 __str__() 없이 __repr__() 만 정의한다면, __repr__() 은 그 클래스 인스턴스의 “비형식적인(informal)” 문자열 표현이 요구될 때 사용될 수 있습니다.

This is typically used for debugging, so it is important that the representation is information-rich and unambiguous. A default implementation is provided by the object class itself.

object.__str__(self)

Called by str(object), the default __format__() implementation, and the built-in function print(), to compute the “informal” or nicely printable string representation of an object. The return value must be a str object.

이 메서드는 __str__() 이 올바른 파이썬 표현식을 돌려줄 것이라고 기대되지 않는다는 점에서 object.__repr__() 과 다릅니다: 더 편리하고 간결한 표현이 사용될 수 있습니다.

내장형 object 에 정의된 기본 구현은 object.__repr__() 을 호출합니다.

object.__bytes__(self)

Called by bytes to compute a byte-string representation of an object. This should return a bytes object. The object class itself does not provide this method.

object.__format__(self, format_spec)

format() 내장 함수, 확대하면, 포맷 문자열 리터럴(formatted string literals) 의 계산과 str.format() 메서드에 의해 호출되어, 객체의 “포맷된” 문자열 표현을 만들어냅니다. format_spec 인자는 요구되는 포맷 옵션들을 포함하는 문자열입니다. format_spec 인자의 해석은 __format__() 을 구현하는 형에 달려있으나, 대부분 클래스는 포매팅을 내향형들의 하나로 위임하거나, 비슷한 포맷 옵션 문법을 사용합니다.

표준 포매팅 문법에 대해서는 포맷 명세 미니 언어 를 참고하면 됩니다.

반환 값은 반드시 문자열이어야 합니다.

The default implementation by the object class should be given an empty format_spec string. It delegates to __str__().

버전 3.4에서 변경: object 의 __format__ 메서드 자신은, 빈 문자열이 아닌 인자가 전달되면 TypeError 를 발생시킵니다.

버전 3.7에서 변경: 이제 object.__format__(x, '') 는 format(str(x), '') 가 아니라 str(x) 와 동등합니다.

object.__lt__(self, other)

object.__le__(self, other)

object.__eq__(self, other)

object.__ne__(self, other)

object.__gt__(self, other)

object.__ge__(self, other)

이것들은 소위 “풍부한 비교(rich comparison)” 메서드입니다. 연산자 기호와 메서드 이름 간의 관계는 다음과 같습니다: x<y 는 x.__lt__(y) 를 호출합니다, x<=y 는 x.__le__(y) 를 호출합니다, x==y 는 x.__eq__(y) 를 호출합니다, x!=y 는 x.__ne__(y) 를 호출합니다, x>y 는 x.__gt__(y) 를 호출합니다, x>=y 는 x.__ge__(y) 를 호출합니다.

A rich comparison method may return the singleton NotImplemented if it does not implement the operation for a given pair of arguments. By convention, False and True are returned for a successful comparison. However, these methods can return any value, so if the comparison operator is used in a Boolean context (e.g., in the condition of an if statement), Python will call bool() on the value to determine if the result is true or false.

By default, object implements __eq__() by using is, returning NotImplemented in the case of a false comparison: True if x is y else NotImplemented. For __ne__(), by default it delegates to __eq__() and inverts the result unless it is NotImplemented. There are no other implied relationships among the comparison operators or default implementations; for example, the truth of (x<y or x==y) does not imply x<=y. To automatically generate ordering operations from a single root operation, see functools.total_ordering().

By default, the object class provides implementations consistent with 값 비교: equality compares according to object identity, and order comparisons raise TypeError. Each default method may generate these results directly, but may also return NotImplemented.

사용자 정의 비교 연산자를 지원하고 딕셔너리 키로 사용될 수 있는 해시 가능 객체를 만드는 것에 관한 몇 가지 중요한 내용이 __hash__() 에 관한 문단에 나옵니다.

There are no swapped-argument versions of these methods (to be used when the left argument does not support the operation but the right argument does); rather, __lt__() and __gt__() are each other’s reflection, __le__() and __ge__() are each other’s reflection, and __eq__() and __ne__() are their own reflection. If the operands are of different types, and the right operand’s type is a direct or indirect subclass of the left operand’s type, the reflected method of the right operand has priority, otherwise the left operand’s method has priority. Virtual subclassing is not considered.

When no appropriate method returns any value other than NotImplemented, the == and != operators will fall back to is and is not, respectively.

object.__hash__(self)

Called by built-in function hash() and for operations on members of hashed collections including set, frozenset, and dict. The __hash__() method should return an integer. The only required property is that objects which compare equal have the same hash value; it is advised to mix together the hash values of the components of the object that also play a part in comparison of objects by packing them into a tuple and hashing the tuple. Example:

def __hash__(self):
    return hash((self.name, self.nick, self.color))

참고

hash() 는 객체가 정의한 __hash__() 메서드가 돌려주는 값을 Py_ssize_t 의 크기로 자릅니다(truncate). 이것은 보통 64-bit 빌드에서는 8바이트고, 32-bit 빌드에서는 4바이트입니다. 만약 객체의 __hash__() 가 서로 다른 비트 크기를 갖는 빌드들 사이에서 함께 사용되어야 한다면, 모든 지원할 빌드들에서의 폭을 검사해야 합니다. 이렇게 하는 쉬운 방법은 python -c "import sys; print(sys.hash_info.width)" 입니다.

If a class does not define an __eq__() method it should not define a __hash__() operation either; if it defines __eq__() but not __hash__(), its instances will not be usable as items in hashable collections. If a class defines mutable objects and implements an __eq__() method, it should not implement __hash__(), since the implementation of hashable collections requires that a key’s hash value is immutable (if the object’s hash value changes, it will be in the wrong hash bucket).

User-defined classes have __eq__() and __hash__() methods by default (inherited from the object class); with them, all objects compare unequal (except with themselves) and x.__hash__() returns an appropriate value such that x == y implies both that x is y and hash(x) == hash(y).

__eq__() 를 재정의하고 __hash__() 를 정의하지 않는 클래스는 __hash__() 가 None 으로 설정됩니다. 클래스의 __hash__() 메서드가 None 이면, 클래스의 인스턴스는 프로그램이 해시값을 얻으려 시도할 때 TypeError 를 일으키고, isinstance(obj, collections.abc.Hashable) 로 검사할 때 해시 가능하지 않다고 올바로 감지됩니다.

만약 __eq__() 를 재정의하는 클래스가 부모 클래스로부터 __hash__() 의 구현을 물려받고 싶으면 인터프리터에게 명시적으로 이렇게 지정해주어야 합니다: __hash__ = <ParentClass>.__hash__.

만약 __eq__() 를 재정의하지 않는 클래스가 해시 지원을 멈추고 싶으면, 클래스 정의에 __hash__ = None 을 포함해야 합니다. 자신의 __hash__() 을 정의한 후에 직접 TypeError 를 일으키는 경우는 isinstance(obj, collections.abc.Hashable) 호출이 해시 가능하다고 잘못 인식합니다.

참고

기본적으로, str과 bytes 객체들의 __hash__() 값은 예측할 수 없는 난수값으로 “솔트되어(salted)” 있습니다. 개별 파이썬 프로세스 내에서는 변하지 않는 값으로 유지되지만, 파이썬을 반복적으로 실행할 때는 예측할 수 없게 됩니다.

This is intended to provide protection against a denial-of-service caused by carefully chosen inputs that exploit the worst case performance of a dict insertion, O(n²) complexity. See http://ocert.org/advisories/ocert-2011-003.html for details.

해시값의 변경은 집합의 이터레이션 순서에 영향을 줍니다, 파이썬은 이 순서에 대해 어떤 보장도 하지 않습니다 (그리고 보통 32-bit 와 64-bit 빌드 사이에서도 다릅니다).

PYTHONHASHSEED 를 참고하십시오.

버전 3.3에서 변경: 해시 난수 화는 기본적으로 활성화됩니다.

object.__bool__(self)

Called to implement truth value testing and the built-in operation bool(); should return False or True. When this method is not defined, __len__() is called, if it is defined, and the object is considered true if its result is nonzero. If a class defines neither __len__() nor __bool__() (which is true of the object class itself), all its instances are considered true.

3.3.2. 어트리뷰트 액세스 커스터마이제이션

클래스 인스턴스의 어트리뷰트 참조(읽기, 대입하기, x.name 을 삭제하기)의 의미를 변경하기 위해 다음과 같은 메서드들이 정의될 수 있습니다.

object.__getattr__(self, name)

Called when the default attribute access fails with an AttributeError (either __getattribute__() raises an AttributeError because name is not an instance attribute or an attribute in the class tree for self; or __get__() of a name property raises AttributeError). This method should either return the (computed) attribute value or raise an AttributeError exception. The object class itself does not provide this method.

Note that if the attribute is found through the normal mechanism, __getattr__() is not called. (This is an intentional asymmetry between __getattr__() and __setattr__().) This is done both for efficiency reasons and because otherwise __getattr__() would have no way to access other attributes of the instance. Note that at least for instance variables, you can take total control by not inserting any values in the instance attribute dictionary (but instead inserting them in another object). See the __getattribute__() method below for a way to actually get total control over attribute access.

object.__getattribute__(self, name)

클래스 인스턴스의 어트리뷰트 액세스를 구현하기 위해 조건 없이 호출됩니다. 만약 클래스가 __getattr__() 도 함께 구현하면, __getattribute__() 가 명시적으로 호출하거나 AttributeError 를 일으키지 않는 이상 __getattr__ 는 호출되지 않습니다. 이 메서드는 어트리뷰트의 (계산된) 값을 돌려주거나 AttributeError 예외를 일으켜야 합니다. 이 메서드에서 무한 재귀(infinite recursion)가 발생하는 것을 막기 위해, 구현은 언제나 필요한 어트리뷰트에 접근하기 위해 같은 이름의 베이스 클래스의 메서드를 호출해야 합니다. 예를 들어, object.__getattribute__(self, name).

참고

This method may still be bypassed when looking up special methods as the result of implicit invocation via language syntax or built-in functions. See 특수 메서드 조회.

특정 민감한 어트리뷰트 액세스의 경우, 인자 obj와 name으로 감사 이벤트 object.__getattr__을 발생시킵니다.

object.__setattr__(self, name, value)

어트리뷰트 대입이 시도될 때 호출됩니다. 일반적인 메커니즘(즉 인스턴스 딕셔너리에 값을 저장하는 것) 대신에 이것이 호출됩니다. name 은 어트리뷰트 이름이고, value 는 그것에 대입하려는 값입니다.

__setattr__() 에서 인스턴스 어트리뷰트에 대입하려고 할 때는, 같은 이름의 베이스 클래스의 메서드를 호출해야 합니다. 예를 들어 object.__setattr__(self, name, value)

특정 민감한 어트리뷰트 대입의 경우, 인자 obj, name, value로 감사 이벤트 object.__setattr__을 발생시킵니다.

object.__delattr__(self, name)

__setattr__() 과 비슷하지만 어트리뷰트를 대입하는 대신에 삭제합니다. 이것은 del obj.name 이 객체에 의미가 있는 경우에만 구현되어야 합니다.

특정 민감한 어트리뷰트 삭제의 경우, 인자 obj와 name으로 감사 이벤트 object.__delattr__을 발생시킵니다.

object.__dir__(self)

Called when dir() is called on the object. An iterable must be returned. dir() converts the returned iterable to a list and sorts it.

3.3.2.1. 모듈 어트리뷰트 액세스 커스터마이제이션

특수한 이름 __getattr__ 과 __dir__ 는 모듈 어트리뷰트에 대한 접근을 사용자 정의하는 데 사용될 수도 있습니다. 모듈 수준의 __getattr__ 함수는 하나의 인자로 어트리뷰트의 이름을 받아서 계산된 값을 돌려주거나 AttributeError 를 발생시켜야 합니다. 일반적인 조회(즉 object.__getattribute__())를 통해 어트리뷰트가 모듈 객체에서 발견되지 않으면, AttributeError 를 일으키기 전에 모듈 __dict__ 에서 __getattr__ 을 검색합니다. 발견되면, 어트리뷰트 이름으로 그 함수를 호출하고 결과를 돌려줍니다.

The __dir__ function should accept no arguments, and return an iterable of strings that represents the names accessible on module. If present, this function overrides the standard dir() search on a module.

모듈 동작(어트리뷰트 설정, 프로퍼티 등)을 보다 세밀하게 사용자 정의하려면, 모듈 객체의 __class__ 어트리뷰트를 types.ModuleType 의 서브 클래스로 설정할 수 있습니다. 예를 들면:

import sys
from types import ModuleType

class VerboseModule(ModuleType):
    def __repr__(self):
        return f'Verbose {self.__name__}'

    def __setattr__(self, attr, value):
        print(f'Setting {attr}...')
        super().__setattr__(attr, value)

sys.modules[__name__].__class__ = VerboseModule

참고

모듈 __getattr__ 정의와 모듈 __class__ 설정은 어트리뷰트 액세스 구문을 사용하는 조회에만 영향을 미칩니다 – 모듈 전역에 대한 직접적인 액세스(모듈 내의 코드에 의한 액세스이거나 모듈의 전역 딕셔너리에 대한 참조를 거치거나)는 영향받지 않습니다.

버전 3.5에서 변경: 이제 __class__ 모듈 어트리뷰트가 쓰기 가능합니다.

Added in version 3.7: __getattr__ 과 __dir__ 모듈 어트리뷰트.

더 보기

PEP 562 [https://peps.python.org/pep-0562/] - 모듈 __getattr__ 과 __dir__

모듈에 대한 __getattr__ 과 __dir__ 함수를 설명합니다.

3.3.2.2. 디스크립터 구현하기

The following methods only apply when an instance of the class containing the method (a so-called descriptor class) appears in an owner class (the descriptor must be in either the owner’s class dictionary or in the class dictionary for one of its parents). In the examples below, “the attribute” refers to the attribute whose name is the key of the property in the owner class’ __dict__. The object class itself does not implement any of these protocols.

object.__get__(self, instance, owner=None)

소유자 클래스(클래스 어트리뷰트 액세스) 나 그 클래스의 인스턴스(인스턴스 어트리뷰트 액세스)의 어트리뷰트를 취하려고 할 때 호출됩니다. 선택적 owner 인자는 소유자 클래스입니다. 반면에 instance 는 어트리뷰트 참조가 일어나고 있는 인스턴스이거나, 어트리뷰트가 owner 를 통해 액세스 되는 경우 None 입니다.

이 메서드는 계산된 어트리뷰트 값을 돌려주거나 AttributeError 예외를 일으켜야 합니다.

PEP 252 [https://peps.python.org/pep-0252/]는 __get__()이 하나나 두 개의 인자를 갖는 콜러블이라고 지정합니다. 파이썬 자신의 내장 디스크립터는 이 명세를 지원합니다; 그러나, 일부 제삼자 도구에는 두 인수를 모두 요구하는 디스크립터가 있을 수 있습니다. 파이썬 자신의 __getattribute__() 구현은 필요한지와 관계없이 항상 두 인자를 모두 전달합니다.

object.__set__(self, instance, value)

소유자 클래스의 인스턴스 instance 의 어트리뷰트를 새 값 value 로 설정할 때 호출됩니다.

__set__()이나 __delete__()를 추가하면 디스크립터 유형이 “데이터 디스크립터(data descriptor)”로 변경됨에 유의하십시오. 자세한 내용은 디스크립터 호출하기를 참조하십시오.

object.__delete__(self, instance)

소유자 클래스의 인스턴스 instance 의 어트리뷰트를 삭제할 때 호출됩니다.

Instances of descriptors may also have the __objclass__ attribute present:

object.__objclass__

The attribute __objclass__ is interpreted by the inspect module as specifying the class where this object was defined (setting this appropriately can assist in runtime introspection of dynamic class attributes). For callables, it may indicate that an instance of the given type (or a subclass) is expected or required as the first positional argument (for example, CPython sets this attribute for unbound methods that are implemented in C).

3.3.2.3. 디스크립터 호출하기

In general, a descriptor is an object attribute with “binding behavior”, one whose attribute access has been overridden by methods in the descriptor protocol: __get__(), __set__(), and __delete__(). If any of those methods are defined for an object, it is said to be a descriptor.

어트리뷰트 액세스의 기본 동작은 객체의 딕셔너리에서 어트리뷰트를 읽고, 쓰고, 삭제하는 것입니다. 예를 들어 a.x 는 a.__dict__['x'] 에서 시작해서 type(a).__dict__['x'] 를 거쳐 type(a) 의 메타 클래스를 제외한 베이스 클래스들을 거쳐 가는 일련의 조회로 구성됩니다.

그러나, 만약 조회한 값이 디스크립터 메서드를 구현한 객체면, 파이썬은 기본 동작 대신에 디스크립터 메서드를 호출할 수 있습니다. 우선순위 목록의 어느 위치에서 이런 일이 일어나는지는 어떤 디스크립터 메서드가 정의되어 있고 어떤 식으로 호출되는지에 따라 다릅니다.

디스크립터 호출의 시작점은 결합(binding)입니다, a.x. 어떻게 인자들이 조합되는지는 a 에 따라 다릅니다:

직접 호출

가장 간단하면서도 가장 덜 사용되는 호출은 사용자의 코드가 디스크립터 메서드를 직접 호출할 때입니다: x.__get__(a)

인스턴스 결합

객체 인스턴스에 결합하면, a.x 는 이런 호출로 변환됩니다: type(a).__dict__['x'].__get__(a, type(a)).

클래스 결합

클래스에 결합하면, A.x 는 이런 호출로 변환됩니다: A.__dict__['x'].__get__(None, A).

Super 결합

A dotted lookup such as super(A, a).x searches a.__class__.__mro__ for a base class B following A and then returns B.__dict__['x'].__get__(a, A). If not a descriptor, x is returned unchanged.

For instance bindings, the precedence of descriptor invocation depends on which descriptor methods are defined. A descriptor can define any combination of __get__(), __set__() and __delete__(). If it does not define __get__(), then accessing the attribute will return the descriptor object itself unless there is a value in the object’s instance dictionary. If the descriptor defines __set__() and/or __delete__(), it is a data descriptor; if it defines neither, it is a non-data descriptor. Normally, data descriptors define both __get__() and __set__(), while non-data descriptors have just the __get__() method. Data descriptors with __get__() and __set__() (and/or __delete__()) defined always override a redefinition in an instance dictionary. In contrast, non-data descriptors can be overridden by instances.

Python methods (including those decorated with @staticmethod and @classmethod) are implemented as non-data descriptors. Accordingly, instances can redefine and override methods. This allows individual instances to acquire behaviors that differ from other instances of the same class.

property() 함수는 데이터 디스크립터로 구현됩니다. 이 때문에, 인스턴스는 프로퍼티(property)의 동작을 변경할 수 없습니다.

3.3.2.4. __slots__

__slots__ allow us to explicitly declare data members (like properties) and deny the creation of __dict__ and __weakref__ (unless explicitly declared in __slots__ or available in a parent.)

The space saved over using __dict__ can be significant. Attribute lookup speed can be significantly improved as well.

object.__slots__

This class variable can be assigned a string, iterable, or sequence of strings with variable names used by instances. __slots__ reserves space for the declared variables and prevents the automatic creation of __dict__ and __weakref__ for each instance.

Notes on using __slots__:

When inheriting from a class without __slots__, the __dict__ and __weakref__ attribute of the instances will always be accessible.

Without a __dict__ variable, instances cannot be assigned new variables not listed in the __slots__ definition. Attempts to assign to an unlisted variable name raises AttributeError. If dynamic assignment of new variables is desired, then add '__dict__' to the sequence of strings in the __slots__ declaration.

Without a __weakref__ variable for each instance, classes defining __slots__ do not support weak references to its instances. If weak reference support is needed, then add '__weakref__' to the sequence of strings in the __slots__ declaration.

__slots__ are implemented at the class level by creating descriptors for each variable name. As a result, class attributes cannot be used to set default values for instance variables defined by __slots__; otherwise, the class attribute would overwrite the descriptor assignment.

The action of a __slots__ declaration is not limited to the class where it is defined. __slots__ declared in parents are available in child classes. However, instances of a child subclass will get a __dict__ and __weakref__ unless the subclass also defines __slots__ (which should only contain names of any additional slots).

클래스가 베이스 클래스의 __slots__ 에 정의된 이름과 같은 이름의 변수를 __slots__ 에 선언한다면, 베이스 클래스가 정의한 변수는 액세스할 수 없는 상태가 됩니다(베이스 클래스로부터 디스크립터를 직접 조회하는 경우는 예외다). 이것은 프로그램을 정의되지 않은 상태로 보내게 됩니다. 미래에는, 이를 방지하기 위한 검사가 추가될 것입니다.

TypeError will be raised if nonempty __slots__ are defined for a class derived from a "variable-length" built-in type such as int, bytes, and tuple.

Any non-string iterable may be assigned to __slots__.

If a dictionary is used to assign __slots__, the dictionary keys will be used as the slot names. The values of the dictionary can be used to provide per-attribute docstrings that will be recognised by inspect.getdoc() and displayed in the output of help().

__class__ assignment works only if both classes have the same __slots__.

Multiple inheritance with multiple slotted parent classes can be used, but only one parent is allowed to have attributes created by slots (the other bases must have empty slot layouts) - violations raise TypeError.

If an iterator is used for __slots__ then a descriptor is created for each of the iterator’s values. However, the __slots__ attribute will be an empty iterator.

3.3.3. 클래스 생성 커스터마이제이션

Whenever a class inherits from another class, __init_subclass__() is called on the parent class. This way, it is possible to write classes which change the behavior of subclasses. This is closely related to class decorators, but where class decorators only affect the specific class they’re applied to, __init_subclass__ solely applies to future subclasses of the class defining the method.

classmethod object.__init_subclass__(cls)

이 메서드는 포함하는 클래스의 서브 클래스가 만들어질 때마다 호출됩니다. cls 는 새 서브 클래스입니다. 만약 일반적인 인스턴스 메서드로 정의되면, 이 메서드는 묵시적으로 클래스 메서드로 변경됩니다.

Keyword arguments which are given to a new class are passed to the parent class’s __init_subclass__. For compatibility with other classes using __init_subclass__, one should take out the needed keyword arguments and pass the others over to the base class, as in:

class Philosopher:
    def __init_subclass__(cls, /, default_name, **kwargs):
        super().__init_subclass__(**kwargs)
        cls.default_name = default_name

class AustralianPhilosopher(Philosopher, default_name="Bruce"):
    pass

기본 구현 object.__init_subclass__ 는 아무 일도 하지 않지만, 인자가 포함되어 호출되면 예외를 발생시킵니다.

참고

메타 클래스 힌트 metaclass 는 나머지 형 절차에 의해 소비되고, __init_subclass__ 로 전달되지 않습니다. 실제 메타 클래스 (명시적인 힌트 대신에) 는 type(cls) 로 액세스할 수 있습니다.

Added in version 3.6.

When a class is created, type.__new__() scans the class variables and makes callbacks to those with a __set_name__() hook.

object.__set_name__(self, owner, name)

Automatically called at the time the owning class owner is created. The object has been assigned to name in that class:

class A:
    x = C()  # Automatically calls: x.__set_name__(A, 'x')

If the class variable is assigned after the class is created, __set_name__() will not be called automatically. If needed, __set_name__() can be called directly:

class A:
   pass

c = C()
A.x = c                  # The hook is not called
c.__set_name__(A, 'x')   # Manually invoke the hook

더 자세한 내용은 클래스 객체 만들기 을 참고하십시오.

Added in version 3.6.

3.3.3.1. 메타 클래스

기본적으로, 클래스는 type() 을 사용해서 만들어집니다. 클래스의 바디는 새 이름 공간에서 실행되고, 클래스 이름은 type(name, bases, namespace) 의 결과에 지역적으로 연결됩니다.

클래스를 만드는 과정은 클래스 정의 줄에 metaclass 키워드 인자를 전달하거나, 그런 인자를 포함한 이미 존재하는 클래스를 계승함으로써 커스터마이즈될 수 있습니다. 다음 예에서, MyClass 와 MySubclass 는 모두 Meta 의 인스턴스입니다.

class Meta(type):
    pass

class MyClass(metaclass=Meta):
    pass

class MySubclass(MyClass):
    pass

클래스 정의에서 지정된 다른 키워드 인자들은 아래에서 설명되는 모든 메타 클래스 연산들로 전달됩니다.

클래스 정의가 실행될 때, 다음과 같은 단계가 수행됩니다.:

MRO 항목이 결정됩니다;

적절한 메타 클래스가 결정됩니다;

클래스 이름 공간이 준비됩니다;

클래스 바디가 실행됩니다;

클래스 객체가 만들어집니다.

3.3.3.2. MRO 항목 결정하기

object.__mro_entries__(self, bases)

If a base that appears in a class definition is not an instance of type, then an __mro_entries__() method is searched on the base. If an __mro_entries__() method is found, the base is substituted with the result of a call to __mro_entries__() when creating the class. The method is called with the original bases tuple passed to the bases parameter, and must return a tuple of classes that will be used instead of the base. The returned tuple may be empty: in these cases, the original base is ignored.

더 보기

types.resolve_bases()

Dynamically resolve bases that are not instances of type.

types.get_original_bases()

Retrieve a class’s “original bases” prior to modifications by __mro_entries__().

PEP 560 [https://peps.python.org/pep-0560/]

Core support for typing module and generic types.

3.3.3.3. 적절한 메타 클래스 선택하기

클래스 정의의 적절한 메타 클래스는 다음과 같이 결정됩니다:

베이스와 명시적인 메타 클래스를 주지 않는 경우 type() 이 사용됩니다;

명시적인 메타 클래스가 지정되고, 그것이 type() 의 인스턴스가 아니면, 그것을 메타 클래스로 사용합니다;

type() 의 인스턴스가 명시적인 메타 클래스로 주어지거나, 베이스가 정의되었으면, 가장 많이 파생된 메타 클래스가 사용됩니다.

가장 많이 파생된 메타 클래스는 명시적으로 지정된 메타 클래스(있다면)와 지정된 모든 베이스 클래스들의 메타 클래스들(즉, type(cls)) 중에서 선택됩니다. 가장 많이 파생된 메타 클래스는 이들 모두 의 서브 타입(subtype)입니다. 만약 어느 것도 이 조건을 만족하지 못한다면, 클래스 정의는 TypeError 를 발생시키며 실패합니다.

3.3.3.4. 클래스 이름 공간 준비하기

Once the appropriate metaclass has been identified, then the class namespace is prepared. If the metaclass has a __prepare__ attribute, it is called as namespace = metaclass.__prepare__(name, bases, **kwds) (where the additional keyword arguments, if any, come from the class definition). The __prepare__ method should be implemented as a classmethod. The namespace returned by __prepare__ is passed in to __new__, but when the final class object is created the namespace is copied into a new dict.

만약 메타 클래스에 __prepare__ 어트리뷰트가 없다면, 클래스 이름 공간은 빈 순서 있는 매핑으로 초기화됩니다.

더 보기

PEP 3115 [https://peps.python.org/pep-3115/] - 파이썬 3000 에서의 메타 클래스

__prepare__ 이름 공간 훅을 도입했습니다

3.3.3.5. 클래스 바디 실행하기

클래스 바디는 (대략) exec(body, globals(), namespace) 과같이 실행됩니다. 일반적인 exec() 호출과 주된 차이점은 클래스 정의가 함수 내부에서 이루어질 때 어휘 스코핑(lexical scoping) 이 클래스 바디(모든 메서드들을 포함해서)로 하여금 현재와 외부 스코프에 있는 이름들을 참조하도록 허락한다는 것입니다.

하지만, 클래스 정의가 함수 내부에서 이루어질 때조차도, 클래스 내부에서 정의된 메서드들은 클래스 스코프에서 정의된 이름들을 볼 수 없습니다. 클래스 변수는 인스턴스나 클래스 메서드의 첫 번째 매개변수를 통해 액세스하거나 다음 섹션에서 설명하는 묵시적으로 어휘 스코핑된 __class__ 참조를 통해야 합니다.

3.3.3.6. 클래스 객체 만들기

일단 클래스 이름 공간이 클래스 바디를 실행함으로써 채워지면, 클래스 객체가 metaclass(name, bases, namespace, **kwds) 을 통해 만들어집니다(여기에서 전달되는 추가적인 키워드 인자들은 __prepare__ 에 전달된 것들과 같습니다).

이 클래스 객체는 super() 에 인자를 주지 않는 경우 참조되는 것입니다. __class__ 는 클래스 바디의 메서드들 중 어느 하나라도 __class__ 나 super 를 참조할 경우 컴파일러에 의해 만들어지는 묵시적인 클로저(closure) 참조입니다. 이것은 인자 없는 형태의 super() 가 어휘 스코핑 기반으로 현재 정의되고 있는 클래스를 올바르게 찾을 수 있도록 합니다. 반면에 현재의 호출에 사용된 클래스나 인스턴스는 메서드로 전달된 첫 번째 인자에 기초해서 식별됩니다.

CPython 구현 상세: CPython 3.6 이상에서, __class__ 셀(cell)은 클래스 이름 공간의 __classcell__ 엔트리로 메타 클래스에 전달됩니다. 만약 존재한다면, 이것은 클래스가 올바르게 초기화되기 위해 type.__new__ 호출까지 거슬러서 전파되어야 합니다. 이렇게 하지 못하면 파이썬 3.8 에서는 RuntimeError로 이어질 것입니다.

When using the default metaclass type, or any metaclass that ultimately calls type.__new__, the following additional customization steps are invoked after creating the class object:

The type.__new__ method collects all of the attributes in the class namespace that define a __set_name__() method;

Those __set_name__ methods are called with the class being defined and the assigned name of that particular attribute;

The __init_subclass__() hook is called on the immediate parent of the new class in its method resolution order.

클래스 객체가 만들어진 후에, 클래스 정의에 포함된 클래스 데코레이터들에게 (있다면) 클래스를 전달하고, 그 결과를 클래스가 정의되는 지역 이름 공간에 연결합니다.

When a new class is created by type.__new__, the object provided as the namespace parameter is copied to a new ordered mapping and the original object is discarded. The new copy is wrapped in a read-only proxy, which becomes the __dict__ attribute of the class object.

더 보기

PEP 3135 [https://peps.python.org/pep-3135/] - 새 super

묵시적인 __class__ 클로저 참조를 설명합니다

3.3.3.7. 메타 클래스의 용도

메타 클래스의 잠재적인 용도에는 한계가 없습니다. 탐색 된 몇 가지 아이디어들에는 enum, 로깅, 인터페이스 검사, 자동화된 위임(automatic delegation), 자동화된 프로퍼티(properety) 생성, 프락시(proxy), 프레임웍(framework), 자동화된 자원 로킹/동기화(automatic resource locking/synchronization) 등이 있습니다.

3.3.4. 인스턴스 및 서브 클래스 검사 커스터마이제이션

다음 메서드들은 isinstance() 와 issubclass() 내장 함수들의 기본 동작을 재정의하는 데 사용됩니다.

특히, 메타 클래스 abc.ABCMeta 는 추상 베이스 클래스(Abstract Base Class, ABC)를 다른 ABC를 포함한 임의의 클래스나 형(내장형을 포함합니다)에 “가상 베이스 클래스(virtual base class)”로 추가할 수 있게 하려고 이 메서드들을 구현합니다.

type.__instancecheck__(self, instance)

instance 가 (직접적이거나 간접적으로) class 의 인스턴스로 취급될 수 있으면 참을 돌려줍니다. 만약 정의되면, isinstance(instance, class) 를 구현하기 위해 호출됩니다.

type.__subclasscheck__(self, subclass)

subclass 가 (직접적이거나 간접적으로) class 의 서브 클래스로 취급될 수 있으면 참을 돌려줍니다. 만약 정의되면, issubclass(subclass, class) 를 구현하기 위해 호출됩니다.

이 메서드들은 클래스의 형(메타 클래스)에서 조회된다는 것에 주의해야 합니다. 실제 클래스에서 클래스 메서드로 정의될 수 없습니다. 이것은 인스턴스에 대해 호출되는 특수 메서드들의 조회와 일관성 있습니다. 이 경우 인스턴스는 클래스 자체다.

더 보기

PEP 3119 [https://peps.python.org/pep-3119/] - 추상 베이스 클래스의 도입

Includes the specification for customizing isinstance() and issubclass() behavior through __instancecheck__() and __subclasscheck__(), with motivation for this functionality in the context of adding Abstract Base Classes (see the abc module) to the language.

3.3.5. 제네릭 형 흉내 내기

When using type annotations, it is often useful to parameterize a generic type using Python’s square-brackets notation. For example, the annotation list[int] might be used to signify a list in which all the elements are of type int.

더 보기

PEP 484 [https://peps.python.org/pep-0484/] - Type Hints

Introducing Python’s framework for type annotations

Generic Alias Types

Documentation for objects representing parameterized generic classes

제네릭, user-defined generics and typing.Generic

Documentation on how to implement generic classes that can be parameterized at runtime and understood by static type-checkers.

A class can generally only be parameterized if it defines the special class method __class_getitem__().

classmethod object.__class_getitem__(cls, key)

key 에 있는 형 인자에 의한 제네릭 클래스의 특수화를 나타내는 객체를 돌려줍니다.

When defined on a class, __class_getitem__() is automatically a class method. As such, there is no need for it to be decorated with @classmethod when it is defined.

3.3.5.1. The purpose of __class_getitem__

The purpose of __class_getitem__() is to allow runtime parameterization of standard-library generic classes in order to more easily apply type hints to these classes.

To implement custom generic classes that can be parameterized at runtime and understood by static type-checkers, users should either inherit from a standard library class that already implements __class_getitem__(), or inherit from typing.Generic, which has its own implementation of __class_getitem__().

Custom implementations of __class_getitem__() on classes defined outside of the standard library may not be understood by third-party type-checkers such as mypy. Using __class_getitem__() on any class for purposes other than type hinting is discouraged.

3.3.5.2. __class_getitem__ versus __getitem__

Usually, the subscription of an object using square brackets will call the __getitem__() instance method defined on the object’s class. However, if the object being subscribed is itself a class, the class method __class_getitem__() may be called instead. __class_getitem__() should return a GenericAlias object if it is properly defined.

Presented with the expression obj[x], the Python interpreter follows something like the following process to decide whether __getitem__() or __class_getitem__() should be called:

from inspect import isclass

def subscribe(obj, x):
    """Return the result of the expression 'obj[x]'"""

    class_of_obj = type(obj)

    # If the class of obj defines __getitem__,
    # call class_of_obj.__getitem__(obj, x)
    if hasattr(class_of_obj, '__getitem__'):
        return class_of_obj.__getitem__(obj, x)

    # Else, if obj is a class and defines __class_getitem__,
    # call obj.__class_getitem__(x)
    elif isclass(obj) and hasattr(obj, '__class_getitem__'):
        return obj.__class_getitem__(x)

    # Else, raise an exception
    else:
        raise TypeError(
            f"'{class_of_obj.__name__}' object is not subscriptable"
        )

In Python, all classes are themselves instances of other classes. The class of a class is known as that class’s metaclass, and most classes have the type class as their metaclass. type does not define __getitem__(), meaning that expressions such as list[int], dict[str, float] and tuple[str, bytes] all result in __class_getitem__() being called:

>>> # list has class "type" as its metaclass, like most classes:
>>> type(list)
<class 'type'>
>>> type(dict) == type(list) == type(tuple) == type(str) == type(bytes)
True
>>> # "list[int]" calls "list.__class_getitem__(int)"
>>> list[int]
list[int]
>>> # list.__class_getitem__ returns a GenericAlias object:
>>> type(list[int])
<class 'types.GenericAlias'>

However, if a class has a custom metaclass that defines __getitem__(), subscribing the class may result in different behaviour. An example of this can be found in the enum module:

>>> from enum import Enum
>>> class Menu(Enum):
...     """A breakfast menu"""
...     SPAM = 'spam'
...     BACON = 'bacon'
...
>>> # Enum classes have a custom metaclass:
>>> type(Menu)
<class 'enum.EnumMeta'>
>>> # EnumMeta defines __getitem__,
>>> # so __class_getitem__ is not called,
>>> # and the result is not a GenericAlias object:
>>> Menu['SPAM']
<Menu.SPAM: 'spam'>
>>> type(Menu['SPAM'])
<enum 'Menu'>

더 보기

PEP 560 [https://peps.python.org/pep-0560/] - Core Support for typing module and generic types

Introducing __class_getitem__(), and outlining when a subscription results in __class_getitem__() being called instead of __getitem__()

3.3.6. 콜러블 객체 흉내 내기

object.__call__(self[, args...])

Called when the instance is “called” as a function; if this method is defined, x(arg1, arg2, ...) roughly translates to type(x).__call__(x, arg1, ...). The object class itself does not provide this method.

3.3.7. 컨테이너형 흉내 내기

The following methods can be defined to implement container objects. None of them are provided by the object class itself. Containers usually are sequences (such as lists or tuples) or mappings (like dictionaries), but can represent other containers as well. The first set of methods is used either to emulate a sequence or to emulate a mapping; the difference is that for a sequence, the allowable keys should be the integers k for which 0 <= k < N where N is the length of the sequence, or slice objects, which define a range of items. It is also recommended that mappings provide the methods keys(), values(), items(), get(), clear(), setdefault(), pop(), popitem(), copy(), and update() behaving similar to those for Python’s standard dictionary objects. The collections.abc module provides a MutableMapping abstract base class to help create those methods from a base set of __getitem__(), __setitem__(), __delitem__(), and keys(). Mutable sequences should provide methods append(), count(), index(), extend(), insert(), pop(), remove(), reverse() and sort(), like Python standard list objects. Finally, sequence types should implement addition (meaning concatenation) and multiplication (meaning repetition) by defining the methods __add__(), __radd__(), __iadd__(), __mul__(), __rmul__() and __imul__() described below; they should not define other numerical operators. It is recommended that both mappings and sequences implement the __contains__() method to allow efficient use of the in operator; for mappings, in should search the mapping’s keys; for sequences, it should search through the values. It is further recommended that both mappings and sequences implement the __iter__() method to allow efficient iteration through the container; for mappings, __iter__() should iterate through the object’s keys; for sequences, it should iterate through the values.

object.__len__(self)

Called to implement the built-in function len(). Should return the length of the object, an integer >= 0. Also, an object that doesn’t define a __bool__() method and whose __len__() method returns zero is considered to be false in a Boolean context.

CPython 구현 상세: In CPython, the length is required to be at most sys.maxsize. If the length is larger than sys.maxsize some features (such as len()) may raise OverflowError. To prevent raising OverflowError by truth value testing, an object must define a __bool__() method.

object.__length_hint__(self)

Called to implement operator.length_hint(). Should return an estimated length for the object (which may be greater or less than the actual length). The length must be an integer >= 0. The return value may also be NotImplemented, which is treated the same as if the __length_hint__ method didn’t exist at all. This method is purely an optimization and is never required for correctness.

Added in version 3.4.

참고

슬라이싱은 전적으로 다음에 나오는 세 메서드들에의해 수행됩니다

a[1:2] = b

과 같은 호출은

a[slice(1, 2, None)] = b

로 번역되고, 다른 형태도 마찬가지입니다. 빠진 슬라이스 항목은 항상 None 으로 채워집니다.

object.__getitem__(self, key)

Called to implement evaluation of self[key]. For sequence types, the accepted keys should be integers. Optionally, they may support slice objects as well. Negative index support is also optional. If key is of an inappropriate type, TypeError may be raised; if key is a value outside the set of indexes for the sequence (after any special interpretation of negative values), IndexError should be raised. For mapping types, if key is missing (not in the container), KeyError should be raised.

참고

for 루프는 시퀀스의 끝을 올바로 감지하기 위해, 잘못된 인덱스에 대해 IndexError 가 일어날 것으로 기대하고 있습니다.

참고

When subscripting a class, the special class method __class_getitem__() may be called instead of __getitem__(). See __class_getitem__ versus __getitem__ for more details.

object.__setitem__(self, key, value)

self[key] 로의 대입을 구현하기 위해 호출됩니다. __getitem__() 과 같은 주의가 필요합니다. 매핑의 경우에는, 객체가 키에 대해 값의 변경이나 새 키의 추가를 허락할 경우, 시퀀스의 경우는 항목이 교체될 수 있을 때만 구현되어야 합니다. 잘못된 key 값의 경우는 __getitem__() 에서와 같은 예외를 일으켜야 합니다.

object.__delitem__(self, key)

self[key] 의 삭제를 구현하기 위해 호출됩니다. __getitem__() 과 같은 주의가 필요합니다. 매핑의 경우에는, 객체가 키의 삭제를 허락할 경우, 시퀀스의 경우는 항목이 시퀀스로부터 제거될 수 있을 때만 구현되어야 합니다. 잘못된 key 값의 경우는 __getitem__() 에서와 같은 예외를 일으켜야 합니다.

object.__missing__(self, key)

dict.__getitem__() 이 dict 서브 클래스에서 키가 딕셔너리에 없으면 self[key] 를 구현하기 위해 호출합니다.

object.__iter__(self)

This method is called when an iterator is required for a container. This method should return a new iterator object that can iterate over all the objects in the container. For mappings, it should iterate over the keys of the container.

object.__reversed__(self)

reversed() 내장 함수가 역 이터레이션(reverse iteration)을 구현하기 위해 (있다면) 호출합니다. 컨테이너에 있는 객체들을 역 순으로 탐색하는 새 이터레이터 객체를 돌려줘야 합니다.

__reversed__() 메서드가 제공되지 않으면, reversed() 내장함수는 시퀀스 프로토콜(__len__() 과 __getitem__())을 대안으로 사용합니다. 시퀀스 프로토콜을 지원하는 객체들은 reversed() 가 제공하는 것보다 더 효율적인 구현을 제공할 수 있을 때만 __reversed__() 를 제공해야 합니다.

멤버십 검사 연산자들(in 과 not in) 은 보통 컨테이너에 대한 이터레이션으로 구현됩니다. 하지만, 컨테이너 객체는 더 효율적인 구현을 다음과 같은 특수 메서드를 통해 제공할 수 있습니다. 이 경우 객체는 이터러블일 필요도 없습니다.

object.__contains__(self, item)

멤버십 검사 연산자를 구현하기 위해 호출됩니다. item 이 self 에 있으면 참을, 그렇지 않으면 거짓을 돌려줘야 합니다. 매핑 객체의 경우, 키-값 쌍이 아니라 매핑의 키가 고려되어야 합니다.

__contains__() 를 정의하지 않는 객체의 경우, 멤버십 검사는 먼저 __iter__() 를 통한 이터레이션을 시도한 후, __getitem__() 을 통한 낡은 시퀀스 이터레이션 프로토콜을 시도합니다. 언어 레퍼런스의 이 절을 참고하십시오.

3.3.8. 숫자 형 흉내 내기

숫자 형을 흉내 내기 위해 다음과 같은 메서드들을 정의할 수 있습니다. 구현되는 특별한 종류의 숫자에 의해 지원되지 않는 연산들(예를 들어, 정수가 아닌 숫자들에 대한 비트 연산들)에 대응하는 메서드들을 정의되지 않은 채로 남겨두어야 합니다.

object.__add__(self, other)

object.__sub__(self, other)

object.__mul__(self, other)

object.__matmul__(self, other)

object.__truediv__(self, other)

object.__floordiv__(self, other)

object.__mod__(self, other)

object.__divmod__(self, other)

object.__pow__(self, other[, modulo])

object.__lshift__(self, other)

object.__rshift__(self, other)

object.__and__(self, other)

object.__xor__(self, other)

object.__or__(self, other)

These methods are called to implement the binary arithmetic operations (+, -, *, @, /, //, %, divmod(), pow(), **, <<, >>, &, ^, |). For instance, to evaluate the expression x + y, where x is an instance of a class that has an __add__() method, type(x).__add__(x, y) is called. The __divmod__() method should be the equivalent to using __floordiv__() and __mod__(); it should not be related to __truediv__(). Note that __pow__() should be defined to accept an optional third argument if the ternary version of the built-in pow() function is to be supported.

If one of those methods does not support the operation with the supplied arguments, it should return NotImplemented.

object.__radd__(self, other)

object.__rsub__(self, other)

object.__rmul__(self, other)

object.__rmatmul__(self, other)

object.__rtruediv__(self, other)

object.__rfloordiv__(self, other)

object.__rmod__(self, other)

object.__rdivmod__(self, other)

object.__rpow__(self, other[, modulo])

object.__rlshift__(self, other)

object.__rrshift__(self, other)

object.__rand__(self, other)

object.__rxor__(self, other)

object.__ror__(self, other)

These methods are called to implement the binary arithmetic operations (+, -, *, @, /, //, %, divmod(), pow(), **, <<, >>, &, ^, |) with reflected (swapped) operands. These functions are only called if the operands are of different types, when the left operand does not support the corresponding operation [3], or the right operand’s class is derived from the left operand’s class. [4] For instance, to evaluate the expression x - y, where y is an instance of a class that has an __rsub__() method, type(y).__rsub__(y, x) is called if type(x).__sub__(x, y) returns NotImplemented or type(y) is a subclass of type(x). [5]

삼 항 pow() 는 __rpow__() 를 호출하려고 시도하지 않음에 주의해야 합니다 (그렇게 하려면 코어션 규칙이 너무 복잡해집니다).

참고

만약 오른쪽 피연산자의 형이 왼쪽 피연산자의 형의 서브 클래스이고, 그 서브 클래스가 연산의 뒤집힌 메서드의 다른 구현을 제공하면, 이 메서드가 왼쪽 연산자의 뒤집히지 않은 메서드보다 먼저 호출됩니다. 이 동작은 서브 클래스가 조상들의 연산을 재정의할 수 있도록 합니다.

object.__iadd__(self, other)

object.__isub__(self, other)

object.__imul__(self, other)

object.__imatmul__(self, other)

object.__itruediv__(self, other)

object.__ifloordiv__(self, other)

object.__imod__(self, other)

object.__ipow__(self, other[, modulo])

object.__ilshift__(self, other)

object.__irshift__(self, other)

object.__iand__(self, other)

object.__ixor__(self, other)

object.__ior__(self, other)

These methods are called to implement the augmented arithmetic assignments (+=, -=, *=, @=, /=, //=, %=, **=, <<=, >>=, &=, ^=, |=). These methods should attempt to do the operation in-place (modifying self) and return the result (which could be, but does not have to be, self). If a specific method is not defined, or if that method returns NotImplemented, the augmented assignment falls back to the normal methods. For instance, if x is an instance of a class with an __iadd__() method, x += y is equivalent to x = x.__iadd__(y) . If __iadd__() does not exist, or if x.__iadd__(y) returns NotImplemented, x.__add__(y) and y.__radd__(x) are considered, as with the evaluation of x + y. In certain situations, augmented assignment can result in unexpected errors (see 덧셈은 작동하는데, 왜 a_tuple[i] += [‘item’]이 예외를 일으킵니까?), but this behavior is in fact part of the data model.

object.__neg__(self)

object.__pos__(self)

object.__abs__(self)

object.__invert__(self)

일 항 산술 연산(-, +, abs(), ~)을 구현하기 위해 호출됩니다.

object.__complex__(self)

object.__int__(self)

object.__float__(self)

내장 함수 complex(), int(), float()를 구현하기 위해 호출됩니다. 적절한 형의 값을 돌려줘야 합니다.

object.__index__(self)

operator.index() 를 구현하기 위해 호출되고, 파이썬이 숫자 객체를 정수 객체로 손실 없이 변환해야 할 때(슬라이싱이나 내장 bin(), hex(), oct() 함수들에서와같이)마다 호출됩니다. 이 메서드의 존재는 숫자 객체가 정수 형임을 가리킵니다. 반드시 정수를 돌려줘야 합니다.

__int__(), __float__() 및 __complex__()가 정의되어 있지 않으면, 해당 내장 함수 int(), float() 및 complex()는 __index__()를 사용합니다.

object.__round__(self[, ndigits])

object.__trunc__(self)

object.__floor__(self)

object.__ceil__(self)

내장 함수 round()와 math 함수 trunc(), floor(), ceil() 을 구현하기 위해 호출됩니다. ndigits 가 __round__() 로 전달되지 않는 한, 이 메서드들은 모두 Integral (보통 int) 로 잘린 객체의 값을 돌려줘야 합니다.

버전 3.14에서 변경: int() no longer delegates to the __trunc__() method.

3.3.9. with 문 컨텍스트 관리자

컨텍스트 관리자 (context manager) 는 with 문을 실행할 때 자리 잡는 실행 컨텍스트(context)를 정의하는 객체입니다. 코드 블록의 실행을 위해, 컨텍스트 관리자는 원하는 실행시간 컨텍스트로의 진입과 탈출을 처리합니다. 컨텍스트 관리자는 보통 with 문(with 문 섹션에서 설명합니다)으로 시작되지만, 그들의 메서드를 호출해서 직접 사용할 수도 있습니다.

컨텍스트 관리자의 전형적인 용도에는 다양한 종류의 전역 상태(global state)를 보관하고 복구하는 것, 자원을 로킹(locking)하고 언로킹(unlocking)하는 것, 열린 파일을 닫는 것 등이 있습니다.

For more information on context managers, see 컨텍스트 관리자 형. The object class itself does not provide the context manager methods.

object.__enter__(self)

이 객체와 연관된 실행시간 컨텍스트에 진입합니다. with 문은 as 절로 지정된 대상이 있다면, 이 메서드의 반환 값을 연결합니다.

object.__exit__(self, exc_type, exc_value, traceback)

이 객체와 연관된 실행시간 컨텍스트를 종료합니다. 매개변수들은 컨텍스트에서 벗어나게 만든 예외를 기술합니다. 만약 컨텍스트가 예외 없이 종료한다면, 세 인자 모두 None 이 됩니다.

만약 예외가 제공되고, 메서드가 예외를 중지시키고 싶으면 (즉 확산하는 것을 막으려면) 참(true)을 돌려줘야 합니다. 그렇지 않으면 예외는 이 메서드가 종료한 후에 계속 진행됩니다.

Note that __exit__() methods should not reraise the passed-in exception; this is the caller’s responsibility.

더 보기

PEP 343 [https://peps.python.org/pep-0343/] - “with” 문

파이썬 with 문에 대한 규격, 배경, 예.

3.3.10. Customizing positional arguments in class pattern matching

When using a class name in a pattern, positional arguments in the pattern are not allowed by default, i.e. case MyClass(x, y) is typically invalid without special support in MyClass. To be able to use that kind of pattern, the class needs to define a __match_args__ attribute.

object.__match_args__

This class variable can be assigned a tuple of strings. When this class is used in a class pattern with positional arguments, each positional argument will be converted into a keyword argument, using the corresponding value in __match_args__ as the keyword. The absence of this attribute is equivalent to setting it to ().

For example, if MyClass.__match_args__ is ("left", "center", "right") that means that case MyClass(x, y) is equivalent to case MyClass(left=x, center=y). Note that the number of arguments in the pattern must be smaller than or equal to the number of elements in __match_args__; if it is larger, the pattern match attempt will raise a TypeError.

Added in version 3.10.

더 보기

PEP 634 [https://peps.python.org/pep-0634/] - Structural Pattern Matching

The specification for the Python match statement.

3.3.11. Emulating buffer types

The buffer protocol provides a way for Python objects to expose efficient access to a low-level memory array. This protocol is implemented by builtin types such as bytes and memoryview, and third-party libraries may define additional buffer types.

While buffer types are usually implemented in C, it is also possible to implement the protocol in Python.

object.__buffer__(self, flags)

Called when a buffer is requested from self (for example, by the memoryview constructor). The flags argument is an integer representing the kind of buffer requested, affecting for example whether the returned buffer is read-only or writable. inspect.BufferFlags provides a convenient way to interpret the flags. The method must return a memoryview object.

object.__release_buffer__(self, buffer)

Called when a buffer is no longer needed. The buffer argument is a memoryview object that was previously returned by __buffer__(). The method must release any resources associated with the buffer. This method should return None. Buffer objects that do not need to perform any cleanup are not required to implement this method.

Added in version 3.12.

더 보기

PEP 688 [https://peps.python.org/pep-0688/] - Making the buffer protocol accessible in Python

Introduces the Python __buffer__ and __release_buffer__ methods.

collections.abc.Buffer

ABC for buffer types.

3.3.12. Annotations

Functions, classes, and modules may contain annotations, which are a way to associate information (usually type hints) with a symbol.

object.__annotations__

This attribute contains the annotations for an object. It is lazily evaluated, so accessing the attribute may execute arbitrary code and raise exceptions. If evaluation is successful, the attribute is set to a dictionary mapping from variable names to annotations.

버전 3.14에서 변경: Annotations are now lazily evaluated.

object.__annotate__(format)

An annotate function. Returns a new dictionary object mapping attribute/parameter names to their annotation values.

Takes a format parameter specifying the format in which annotations values should be provided. It must be a member of the annotationlib.Format enum, or an integer with a value corresponding to a member of the enum.

If an annotate function doesn’t support the requested format, it must raise NotImplementedError. Annotate functions must always support VALUE format; they must not raise NotImplementedError() when called with this format.

When called with VALUE format, an annotate function may raise NameError; it must not raise NameError when called requesting any other format.

If an object does not have any annotations, __annotate__ should preferably be set to None (it can’t be deleted), rather than set to a function that returns an empty dict.

Added in version 3.14.

더 보기

PEP 649 [https://peps.python.org/pep-0649/] — Deferred evaluation of annotation using descriptors

Introduces lazy evaluation of annotations and the __annotate__ function.

3.3.13. 특수 메서드 조회

사용자 정의 클래스의 경우, 묵시적인 특수 메서드의 호출은 객체의 인스턴스 딕셔너리가 아닌 객체의 형에 정의되어 있을 때만 올바르게 동작함이 보장됩니다. 이런 동작은 다음과 같은 코드가 예외를 일으키는 원인입니다:

>>> class C:
...     pass
...
>>> c = C()
>>> c.__len__ = lambda: 5
>>> len(c)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: object of type 'C' has no len()

The rationale behind this behaviour lies with a number of special methods such as __hash__() and __repr__() that are implemented by all objects, including type objects. If the implicit lookup of these methods used the conventional lookup process, they would fail when invoked on the type object itself:

>>> 1 .__hash__() == hash(1)
True
>>> int.__hash__() == hash(int)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: descriptor '__hash__' of 'int' object needs an argument

클래스의 연결되지 않은 메서드를 호출하려는 이런 식의 잘못된 시도는 종종 ‘메타 클래스 혼란(metaclass confusion)’ 이라고 불리고, 특수 메서드를 조회할 때 인스턴스를 우회하는 방법으로 피할 수 있습니다.

>>> type(1).__hash__(1) == hash(1)
True
>>> type(int).__hash__(int) == hash(int)
True

In addition to bypassing any instance attributes in the interest of correctness, implicit special method lookup generally also bypasses the __getattribute__() method even of the object’s metaclass:

>>> class Meta(type):
...     def __getattribute__(*args):
...         print("Metaclass getattribute invoked")
...         return type.__getattribute__(*args)
...
>>> class C(object, metaclass=Meta):
...     def __len__(self):
...         return 10
...     def __getattribute__(*args):
...         print("Class getattribute invoked")
...         return object.__getattribute__(*args)
...
>>> c = C()
>>> c.__len__()                 # Explicit lookup via instance
Class getattribute invoked
10
>>> type(c).__len__(c)          # Explicit lookup via type
Metaclass getattribute invoked
10
>>> len(c)                      # Implicit lookup
10

Bypassing the __getattribute__() machinery in this fashion provides significant scope for speed optimisations within the interpreter, at the cost of some flexibility in the handling of special methods (the special method must be set on the class object itself in order to be consistently invoked by the interpreter).

3.4. 코루틴(Coroutines)

3.4.1. 어웨이터블 객체(Awaitable Objects)

An awaitable object generally implements an __await__() method. Coroutine objects returned from async def functions are awaitable.

참고

The generator iterator objects returned from generators decorated with types.coroutine() are also awaitable, but they do not implement __await__().

object.__await__(self)

Must return an iterator. Should be used to implement awaitable objects. For instance, asyncio.Future implements this method to be compatible with the await expression. The object class itself is not awaitable and does not provide this method.

참고

The language doesn’t place any restriction on the type or value of the objects yielded by the iterator returned by __await__, as this is specific to the implementation of the asynchronous execution framework (e.g. asyncio) that will be managing the awaitable object.

Added in version 3.5.

더 보기

PEP 492 [https://peps.python.org/pep-0492/] 가 어웨이터블 객체에 대한 더 자세한 정보를 포함하고 있습니다.

3.4.2. 코루틴 객체(Coroutine Objects)

Coroutine objects are awaitable objects. A coroutine’s execution can be controlled by calling __await__() and iterating over the result. When the coroutine has finished executing and returns, the iterator raises StopIteration, and the exception’s value attribute holds the return value. If the coroutine raises an exception, it is propagated by the iterator. Coroutines should not directly raise unhandled StopIteration exceptions.

코루틴은 다음에 나열하는 메서드들 또한 갖고 있는데, 제너레이터(제너레이터-이터레이터 메서드 를 보십시오)의 것들과 닮았습니다. 하지만, 제너레이터와는 달리, 코루틴은 이터레이션을 직접 지원하지는 않습니다.

버전 3.5.2에서 변경: 코루틴을 두 번 await 하면 RuntimeError 를 일으킵니다.

coroutine.send(value)

Starts or resumes execution of the coroutine. If value is None, this is equivalent to advancing the iterator returned by __await__(). If value is not None, this method delegates to the send() method of the iterator that caused the coroutine to suspend. The result (return value, StopIteration, or other exception) is the same as when iterating over the __await__() return value, described above.

coroutine.throw(value)

coroutine.throw(type[, value[, traceback]])

Raises the specified exception in the coroutine. This method delegates to the throw() method of the iterator that caused the coroutine to suspend, if it has such a method. Otherwise, the exception is raised at the suspension point. The result (return value, StopIteration, or other exception) is the same as when iterating over the __await__() return value, described above. If the exception is not caught in the coroutine, it propagates back to the caller.

버전 3.12에서 변경: The second signature (type[, value[, traceback]]) is deprecated and may be removed in a future version of Python.

coroutine.close()

코루틴이 자신을 정리하고 종료하도록 만듭니다. 만약 코루틴이 일시 중지 중이면, 이 메서드는 먼저 코루틴이 일시 중지되도록 한 이터레이터의 close() 메서드로 위임합니다(그런 메서드를 가지는 경우). 그런 다음 일시 중지지점에서 GeneratorExit 를 발생시키는데, 코루틴이 즉시 자신을 정리하도록 만듭니다. 마지막으로 코루틴에 실행을 종료했다고 표시하는데, 아직 시작하지조차 않았을 때도 그렇다.

코루틴 객체가 파괴될 때는 위의 프로세스에 따라 자동으로 닫힙니다(closed).

3.4.3. 비동기 이터레이터(Asynchronous Iterators)

비동기 이터레이터 는 자신의 __anext__ 메서드에서 비동기 코드를 호출할 수 있습니다.

비동기 이터레이터는 async for 문에서 사용될 수 있습니다.

The object class itself does not provide these methods.

object.__aiter__(self)

비동기 이터레이터 객체를 돌려줘야 합니다.

object.__anext__(self)

이터레이터의 다음 값을 주는 어웨이터블 을 돌려줘야 합니다. 이터레이션이 끝나면 StopAsyncIteration 에러를 일으켜야 합니다.

비동기 이터러블 객체의 예:

class Reader:
    async def readline(self):
        ...

    def __aiter__(self):
        return self

    async def __anext__(self):
        val = await self.readline()
        if val == b'':
            raise StopAsyncIteration
        return val

Added in version 3.5.

버전 3.7에서 변경: Prior to Python 3.7, __aiter__() could return an awaitable that would resolve to an asynchronous iterator.

Starting with Python 3.7, __aiter__() must return an asynchronous iterator object. Returning anything else will result in a TypeError error.

3.4.4. 비동기 컨텍스트 관리자

비동기 컨텍스트 관리자(asynchronous context manager) 는 __aenter__ 와 __aexit__ 메서드에서 실행을 일시 중지할 수 있는 컨텍스트 관리자 입니다.

비동기 컨텍스트 관리자는 async with 문에서 사용될 수 있습니다.

The object class itself does not provide these methods.

object.__aenter__(self)

Semantically similar to __enter__(), the only difference being that it must return an awaitable.

object.__aexit__(self, exc_type, exc_value, traceback)

Semantically similar to __exit__(), the only difference being that it must return an awaitable.

비동기 컨텍스트 관리자 클래스의 예:

class AsyncContextManager:
    async def __aenter__(self):
        await log('entering context')

    async def __aexit__(self, exc_type, exc, tb):
        await log('exiting context')

Added in version 3.5.

각주

[1]

어떤 제한된 조건으로, 어떤 경우에 객체의 형을 변경하는 것이 가능합니다. 하지만 잘못 다뤄지면 아주 괴상한 결과로 이어질 수 있으므로 일반적으로 좋은 생각이 아닙니다.

[2]

The __hash__(), __iter__(), __reversed__(), __contains__(), __class_getitem__() and __fspath__() methods have special handling for this. Others will still raise a TypeError, but may do so by relying on the behavior that None is not callable.

[3]

“Does not support” here means that the class has no such method, or the method returns NotImplemented. Do not set the method to None if you want to force fallback to the right operand’s reflected method—that will instead have the opposite effect of explicitly blocking such fallback.

[4]

For operands of the same type, it is assumed that if the non-reflected method (such as __add__()) fails then the operation is not supported, which is why the reflected method is not called.

[5]

If the right operand’s type is a subclass of the left operand’s type, the reflected method having precedence allows subclasses to override their ancestors’ operations.

4. 실행 모델

4.1. 프로그램의 구조

파이썬 프로그램은 코드 블록으로 만들어집니다. 블록 (block) 은 한 단위로 실행되는 한 조각의 파이썬 프로그램 텍스트입니다. 다음과 같은 것들이 블록입니다: 모듈, 함수 바디, 클래스 정의. 대화형으로 입력되는 각 명령은 블록입니다. 스크립트 파일(표준 입력을 통해 인터프리터로 제공되는 파일이나 인터프리터에 명령행 인자로 지정된 파일)은 코드 블록입니다. 스크립트 명령(-c 옵션으로 인터프리터 명령행에 지정된 명령)은 코드 블록입니다. -m 인자를 사용하여 명령 줄에서 최상위 수준 스크립트로 (모듈 __main__으로) 실행되는 모듈도 코드 블록입니다. 내장함수 eval() 과 exec() 로 전달되는 문자열 인자도 코드 블록입니다.

코드 블록은 실행 프레임 (execution frame) 에서 실행됩니다. 프레임은 몇몇 관리를 위한 정보(디버깅에 사용됩니다)를 포함하고, 코드 블록의 실행이 끝난 후에 어디서 어떻게 실행을 계속할 것인지를 결정합니다.

4.2. 이름과 연결(binding)

4.2.1. 이름의 연결

이름 (Names) 은 객체를 가리킵니다. 이름은 이름 연결 연산 때문에 만들어집니다.

The following constructs bind names:

formal parameters to functions,

class definitions,

function definitions,

assignment expressions,

targets that are identifiers if occurring in an assignment:

for loop header,

after as in a with statement, except clause, except* clause, or in the as-pattern in structural pattern matching,

in a capture pattern in structural pattern matching

import statements.

type statements.

type parameter lists.

The import statement of the form from ... import * binds all names defined in the imported module, except those beginning with an underscore. This form may only be used at the module level.

del 문에 나오는 대상 역시 이 목적에서 연결된 것으로 간주합니다(실제 의미가 이름을 연결 해제하는 것이기는 해도).

각 대입이나 임포트 문은 클래스나 함수 정의 때문에 정의되는 블록 내에 등장할 수 있고, 모듈 수준(최상위 코드 블록)에서 등장할 수도 있습니다.

If a name is bound in a block, it is a local variable of that block, unless declared as nonlocal or global. If a name is bound at the module level, it is a global variable. (The variables of the module code block are local and global.) If a variable is used in a code block but not defined there, it is a free variable.

프로그램 텍스트에 등장하는 각각의 이름들은 다음에 나오는 이름 검색(name resolution) 규칙에 따라 확정되는 이름의 연결 (binding) 을 가리킵니다.

4.2.2. 이름의 검색(resolution)

스코프 (scope) 는 블록 내에서 이름의 가시성(visibility)을 정의합니다. 지역 변수가 블록에서 정의되면, 그것의 스코프는 그 블록을 포함합니다. 만약 정의가 함수 블록에서 이루어지면, 포함된 블록이 그 이름에 대해 다른 결합을 만들지 않는 이상, 스코프는 정의하고 있는 것 안에 포함된 모든 블록으로 확대됩니다.

이름이 코드 블록 내에서 사용될 때, 가장 가깝게 둘러싸고 있는 스코프에 있는 것으로 검색됩니다. 코드 블록이 볼 수 있는 모든 스코프의 집합을 블록의 환경 (environment) 이라고 부릅니다.

이름이 어디에서도 발견되지 않으면 NameError 예외가 발생합니다. 만약 현재 스코프가 함수 스코프이고, 그 이름이 사용되는 시점에 아직 연결되지 않은 지역 변수면 UnboundLocalError 예외가 발생합니다. UnboundLocalError 는 NameError 의 서브 클래스입니다.

If a name binding operation occurs anywhere within a code block, all uses of the name within the block are treated as references to the current block. This can lead to errors when a name is used within a block before it is bound. This rule is subtle. Python lacks declarations and allows name binding operations to occur anywhere within a code block. The local variables of a code block can be determined by scanning the entire text of the block for name binding operations. See the FAQ entry on UnboundLocalError for examples.

If the global statement occurs within a block, all uses of the names specified in the statement refer to the bindings of those names in the top-level namespace. Names are resolved in the top-level namespace by searching the global namespace, i.e. the namespace of the module containing the code block, and the builtins namespace, the namespace of the module builtins. The global namespace is searched first. If the names are not found there, the builtins namespace is searched next. If the names are also not found in the builtins namespace, new variables are created in the global namespace. The global statement must precede all uses of the listed names.

global 문은 같은 블록의 이름 연결 연산과 같은 스코프를 갖습니다. 자유 변수의 경우 가장 가까이서 둘러싸는 스코프가 global 문을 포함한다면, 그 자유 변수는 전역으로 취급됩니다.

The nonlocal statement causes corresponding names to refer to previously bound variables in the nearest enclosing function scope. SyntaxError is raised at compile time if the given name does not exist in any enclosing function scope. Type parameters cannot be rebound with the nonlocal statement.

모듈의 이름 공간은 모듈이 처음 임포트될 때 자동으로 만들어집니다. 스크립트의 메인 모듈은 항상 __main__ 이라고 불립니다.

Class definition blocks and arguments to exec() and eval() are special in the context of name resolution. A class definition is an executable statement that may use and define names. These references follow the normal rules for name resolution with an exception that unbound local variables are looked up in the global namespace. The namespace of the class definition becomes the attribute dictionary of the class. The scope of names defined in a class block is limited to the class block; it does not extend to the code blocks of methods. This includes comprehensions and generator expressions, but it does not include annotation scopes, which have access to their enclosing class scopes. This means that the following will fail:

class A:
    a = 42
    b = list(a + i for i in range(10))

However, the following will succeed:

class A:
    type Alias = Nested
    class Nested: pass

print(A.Alias.__value__)  # <type 'A.Nested'>

4.2.3. Annotation scopes

Annotations, type parameter lists and type statements introduce annotation scopes, which behave mostly like function scopes, but with some exceptions discussed below.

Annotation scopes are used in the following contexts:

Function annotations.

Variable annotations.

Type parameter lists for generic type aliases.

Type parameter lists for generic functions. A generic function’s annotations are executed within the annotation scope, but its defaults and decorators are not.

Type parameter lists for generic classes. A generic class’s base classes and keyword arguments are executed within the annotation scope, but its decorators are not.

The bounds, constraints, and default values for type parameters (lazily evaluated).

The value of type aliases (lazily evaluated).

Annotation scopes differ from function scopes in the following ways:

Annotation scopes have access to their enclosing class namespace. If an annotation scope is immediately within a class scope, or within another annotation scope that is immediately within a class scope, the code in the annotation scope can use names defined in the class scope as if it were executed directly within the class body. This contrasts with regular functions defined within classes, which cannot access names defined in the class scope.

Expressions in annotation scopes cannot contain yield, yield from, await, or := expressions. (These expressions are allowed in other scopes contained within the annotation scope.)

Names defined in annotation scopes cannot be rebound with nonlocal statements in inner scopes. This includes only type parameters, as no other syntactic elements that can appear within annotation scopes can introduce new names.

While annotation scopes have an internal name, that name is not reflected in the qualified name of objects defined within the scope. Instead, the __qualname__ of such objects is as if the object were defined in the enclosing scope.

Added in version 3.12: Annotation scopes were introduced in Python 3.12 as part of PEP 695 [https://peps.python.org/pep-0695/].

버전 3.13에서 변경: Annotation scopes are also used for type parameter defaults, as introduced by PEP 696 [https://peps.python.org/pep-0696/].

버전 3.14에서 변경: Annotation scopes are now also used for annotations, as specified in PEP 649 [https://peps.python.org/pep-0649/] and PEP 749 [https://peps.python.org/pep-0749/].

4.2.4. Lazy evaluation

Most annotation scopes are lazily evaluated. This includes annotations, the values of type aliases created through the type statement, and the bounds, constraints, and default values of type variables created through the type parameter syntax. This means that they are not evaluated when the type alias or type variable is created, or when the object carrying annotations is created. Instead, they are only evaluated when necessary, for example when the __value__ attribute on a type alias is accessed.

Example:

>>> type Alias = 1/0
>>> Alias.__value__
Traceback (most recent call last):
  ...
ZeroDivisionError: division by zero
>>> def func[T: 1/0](): pass
>>> T = func.__type_params__[0]
>>> T.__bound__
Traceback (most recent call last):
  ...
ZeroDivisionError: division by zero

Here the exception is raised only when the __value__ attribute of the type alias or the __bound__ attribute of the type variable is accessed.

This behavior is primarily useful for references to types that have not yet been defined when the type alias or type variable is created. For example, lazy evaluation enables creation of mutually recursive type aliases:

from typing import Literal

type SimpleExpr = int | Parenthesized
type Parenthesized = tuple[Literal["("], Expr, Literal[")"]]
type Expr = SimpleExpr | tuple[SimpleExpr, Literal["+", "-"], Expr]

Lazily evaluated values are evaluated in annotation scope, which means that names that appear inside the lazily evaluated value are looked up as if they were used in the immediately enclosing scope.

Added in version 3.12.

4.2.5. builtins 와 제한된 실행

CPython 구현 상세: 사용자는 __builtins__ 를 건드리지 말아야 합니다; 이것은 구현 세부사항입니다. 내장 이름 공간의 값을 변경하고 싶은 사용자는 builtins 모듈을 import 하고 그것의 어트리뷰트를 적절하게 수정해야 합니다.

코드 블록의 실행과 연관된 내장 이름 공간은, 사실 전역 이름 공간의 이름 __builtins__ 를 조회함으로써 발견됩니다. 이것은 딕셔너리나 모듈이어야 합니다(후자의 경우 모듈의 딕셔너리가 사용됩니다). 기본적으로, __main__ 모듈에 있을 때는 __builtins__ 가 내장 모듈 builtins 이고, 다른 모듈에 있을 때는 __builtins__ 는 builtins 모듈의 딕셔너리에 대한 별칭입니다.

4.2.6. 동적 기능과의 상호작용

자유 변수에 대해 이름 검색은 컴파일 시점이 아니라 실행 시점에 이루어집니다. 이것은 다음과 같은 코드가 42를 출력한다는 것을 뜻합니다:

i = 10
def f():
    print(i)
i = 42
f()

eval() 과 exec() 함수는 이름 검색을 위한 완전한 환경에 대한 접근권이 없습니다. 이름은 호출자의 지역과 전역 이름 공간에서 검색될 수 있습니다. 자유 변수는 가장 가까이 둘러싼 이름 공간이 아니라 전역 이름 공간에서 검색됩니다. [1] exec() 과 eval() 함수에는 전역과 지역 이름 공간을 재정의할 수 있는 생략 가능한 인자가 있습니다. 만약 단지 한 이름 공간만 주어지면, 그것이 두 가지 모두로 사용됩니다.

4.3. 예외

예외는 에러나 예외적인 조건을 처리하기 위해 코드 블록의 일반적인 제어 흐름을 깨는 수단입니다. 에러가 감지된 지점에서 예외를 일으킵니다(raised); 둘러싼 코드 블록이나 직접적 혹은 간접적으로 에러가 발생한 코드 블록을 호출한 어떤 코드 블록에서건 예외는 처리될 수 있습니다.

파이썬 인터프리터는 실행 시간 에러(0으로 나누는 것 같은)를 감지할 때 예외를 일으킵니다. 파이썬 프로그램은 raise 문을 사용해서 명시적으로 예외를 일으킬 수 있습니다. 예외 처리기는 try … except 문으로 지정됩니다. 그런 문장에서 finally 구는 정리(cleanup) 코드를 지정하는 데 사용되는데, 예외를 처리하는 것이 아니라 앞선 코드에서 예외가 발생하건 그렇지 않건 실행됩니다.

파이썬은 에러 처리에 “종결 (termination)” 모델을 사용합니다; 예외 처리기가 뭐가 발생했는지 발견할 수 있고, 바깥 단계에서 실행을 계속할 수는 있지만, 에러의 원인을 제거한 후에 실패한 연산을 재시도할 수는 없습니다(문제의 코드 조각을 처음부터 다시 시작시키는 것은 예외입니다).

예외가 어디서도 처리되지 않을 때, 인터프리터는 프로그램의 실행을 종료하거나, 대화형 메인 루프로 돌아갑니다. 두 경우 모두, 예외가 SystemExit 인 경우를 제외하고, 스택 트레이스백을 인쇄합니다.

Exceptions are identified by class instances. The except clause is selected depending on the class of the instance: it must reference the class of the instance or a non-virtual base class thereof. The instance can be received by the handler and can carry additional information about the exceptional condition.

참고

예외 메시지는 파이썬 API 일부가 아닙니다. 그 내용은 파이썬의 버전이 바뀔 때 경고 없이 변경될 수 있고, 코드는 여러 버전의 인터프리터에서 실행될 수 있는 코드는 이것에 의존하지 말아야 합니다.

섹션 try 문 에서 try 문, raise 문 에서 raise 문에 대한 설명이 제공됩니다.

각주

[1]

이 한계는 이 연산들 때문에 실행되는 코드가 모듈이 컴파일되는 시점에는 존재하지 않았기 때문입니다.

5. 임포트 시스템

한 모듈 에 있는 파이썬 코드는 임포팅 이라는 프로세스를 통해 다른 모듈에 있는 코드들에 대한 접근권을 얻습니다. import 문은 임포트 절차를 일으키는 가장 흔한 방법이지만, 유일한 방법은 아닙니다. importlib.import_module() 같은 함수나 내장 __import__() 도 임포트 절차를 일으키는데 사용될 수 있습니다.

import 문은 두 가지 연산을 합친 것입니다; 먼저 이름이 가리키는 모듈을 찾은 후에, 그 검색의 결과를 지역 스코프의 이름에 연결합니다. import 문의 검색 연산은 적절한 인자들로 __import__() 함수를 호출하는 것으로 정의됩니다. __import__() 의 반환 값은 import 문의 이름 연결 연산을 수행하는 데 사용됩니다. 이 이름 연결 연산의 정확한 세부사항에 대해서는 import 문을 보세요.

__import__() 의 직접 호출은 모듈을 찾고, 발견된다면, 모듈을 만드는 연산만을 수행합니다. 부모 패키지를 임포트하거나 여러 캐시(sys.modules 를 포함합니다)를 갱신하는 것과 같은 부수적인 효과들이 일어날 수 있기는 하지만, 오직 import 문만이 이름 연결 연산을 수행합니다.

import 문이 실행될 때, 표준 내장 __import__() 가 호출됩니다. 임포트 시스템을 호출하는 다른 메커니즘 (importlib.import_module() 같은)은 __import__() 를 사용하지 않고 임포트 개념을 구현하기 위한 자신의 방법을 사용할 수 있습니다.

모듈이 처음 임포트 될 때, 파이썬은 모듈을 검색하고, 발견된다면, 모듈 객체를 만들고 [1], 초기화합니다. 만약 그 이름의 모듈을 발견할 수 없다면, ModuleNotFoundError 를 일으킵니다. 파이썬은 임포트 절차가 호출될 때 이름 붙여진 모듈을 찾는 다양한 전략을 구현합니다. 이 전략들은 다음 섹션에서 설명하는 여러 가지 훅을 통해 수정되고 확장될 수 있습니다.

버전 3.3에서 변경: 임포트 시스템은 PEP 302 [https://peps.python.org/pep-0302/] 의 두 번째 단계를 완전히 구현하도록 개정되었습니다. 이제 묵시적인 임포트 절차는 없습니다 - 전체 임포트 시스템이 sys.meta_path 을 통해 노출됩니다. 여기에 더해, 네이티브(native) 이름 공간 패키지의 지원이 구현되었습니다 (PEP 420 [https://peps.python.org/pep-0420/] 을 보세요).

5.1. importlib

importlib 모듈은 임포트 시스템과 상호 작용하기 위한 풍부한 API를 제공합니다. 예를 들어, importlib.import_module() 는 임포트 절차를 구동하는 데 있어 내장 __import__() 에 비해 권장되고, 더 간단한 API를 제공합니다. 더 상세한 내용은 importlib 라이브러리 설명서를 참조하십시오.

5.2. 패키지(package)

파이썬은 한 가지 종류의 모듈 객체만 갖고 있고, 모든 모듈은 모듈이 파이썬이나 C나 그 밖의 다른 어떤 방법으로 구현되었는지와 상관없이 이 형입니다. 모듈을 조직화하고 이름 계층구조를 제공하기 위해, 파이썬은 패키지 라는 개념을 갖고 있습니다.

패키지를 파일 시스템에 있는 디렉터리라고 생각할 수 있지만, 패키지와 모듈이 파일시스템으로부터 올 필요는 없으므로 이 비유를 너무 문자 그대로 해석하지 말아야 합니다. 이 문서의 목적상, 디렉터리와 파일이라는 비유를 사용할 것입니다. 파일 시스템 디렉터리처럼, 패키지는 계층적으로 조직화하고, 패키지는 보통 모듈뿐만 아니라 서브 패키지도 포함할 수 있습니다.

모든 패키지가 모듈이라는 것을 기억하는 것이 중요합니다. 하지만 모든 모듈이 패키지인 것은 아닙니다. 다른 식으로 표현하면, 패키지는 특별한 종류의 모듈입니다. 구체적으로, __path__ 어트리뷰트를 포함하는 모든 모듈은 패키지로 취급됩니다.

All modules have a name. Subpackage names are separated from their parent package name by a dot, akin to Python’s standard attribute access syntax. Thus you might have a package called email, which in turn has a subpackage called email.mime and a module within that subpackage called email.mime.text.

5.2.1. 정규 패키지

파이썬은 두 가지 종류의 패키지를 정의합니다, 정규 패키지 와 이름 공간 패키지. 정규 패키지는 파이썬 3.2와 그 이전에 존재하던 전통적인 패키지입니다. 정규 패키지는 보통 __init__.py 파일을 가진 디렉터리로 구현됩니다. 정규 패키지가 임포트될 때, 이 __init__.py 파일이 묵시적으로 실행되고, 그것이 정의하는 객체들이 패키지의 이름 공간의 이름들도 연결됩니다. __init__.py 파일은 다른 모듈들이 가질 수 있는 것과 같은 파이썬 코드를 포함할 수 있고, 파이썬은 임포트될 때 모듈에 몇 가지 어트리뷰트를 추가합니다.

예를 들어, 다음과 같은 파일시스템 배치는 최상위 parent 패키지와 세 개의 서브 패키지를 정의합니다:

parent/
    __init__.py
    one/
        __init__.py
    two/
        __init__.py
    three/
        __init__.py

parent.one 을 임포트하면 parent/__init__.py 과 parent/one/__init__.py 을 묵시적으로 실행합니다. 뒤이은 parent.two 와 parent.three 의 임포트는 각각 parent/two/__init__.py 와 parent/three/__init__.py 를 실행합니다.

5.2.2. 이름 공간 패키지

이름 공간 패키지는 여러 가지 포션 들의 복합체인데, 각 포션들은 부모 패키지의 서브 패키지로 이바지합니다. 포션들은 파일시스템의 다른 위치에 놓일 수 있습니다. 포션들은 zip 파일이나 네트워크나 파이썬이 임포트 할 때 검색하는 어떤 다른 장소에서 발견될 수 있습니다. 이름 공간 패키지는 파일시스템의 객체와 직접적인 상관관계가 있을 수도 있고 그렇지 않을 수도 있습니다; 구체적인 형태가 없는 가상 모듈일 수도 있습니다.

이름 공간 패키지는 __path__ 어트리뷰트로 일반적인 리스트를 사용하지 않습니다. 대신에 특별한 이터러블 형을 사용하는데, 그 패키지 내의 다음 임포트 시도에서 그것의 부모 패키지(또는 최상위 패키지의 경우 sys.path) 의 경로가 변했으면 패키지 포션에 대한 새 검색을 자동으로 수행하게 됩니다.

이름 공간 패키지의 경우, parent/__init__.py 파일이 없습니다. 사실, 임포트 검색 동안 여러 개의 parent 디렉터리가 발견될 수 있고, 각각의 것은 다른 포션들에 의해 제공됩니다. 그래서 parent/one 은 물리적으로 parent/two 옆에 위치하지 않을 수 있습니다. 이 경우, 파이썬은 자신 또는 서브 패키지 중 어느 하나가 임포트 될 때마다 최상위 parent 패키지를 위한 이름 공간 패키지를 만듭니다.

이름 공간 패키지의 규격은 PEP 420 [https://peps.python.org/pep-0420/] 을 참조하세요.

5.3. 검색

검색을 시작하기 위해, 파이썬은 임포트될 모듈(또는 패키지, 하지만 이 논의에서 차이점은 중요하지 않다)의 완전히 정규화된 이름 을 필요로 합니다. 이 이름은 import 문으로 제공된 여러 인자나, importlib.import_module() 나 __import__() 함수로 전달된 매개변수들로부터 옵니다.

이 이름은 임포트 검색의 여러 단계에서 사용되는데, 서브 모듈로 가는 점으로 구분된 경로일 수 있습니다, 예를 들어 foo.bar.baz. 이 경우에, 파이썬은 먼저 foo 를, 그다음에 foo.bar 를, 마지막으로 foo.bar.baz 를 임포트하려고 시도합니다. 만약 중간 임포트가 어느 하나라도 실패한다면 ModuleNotFoundError 가 발생합니다.

5.3.1. 모듈 캐시

임포트 검색 도중 처음으로 검사되는 장소는 sys.modules 입니다. 이 매핑은 중간 경로들을 포함해서 전에 임포트 된 모든 모듈의 캐시로 기능합니다. 그래서 만약 foo.bar.baz 가 앞서 임포트 되었다면, sys.modules 는 foo, foo.bar, foo.bar.baz 항목들을 포함합니다. 각 키에 대응하는 값들은 모듈 객체입니다.

임포트하는 동안, 모듈 이름을 sys.modules 에서 찾고, 만약 있다면 해당 값이 임포트를 만족하는 모듈이고, 프로세스는 완료됩니다. 하지만 값이 None 이면, ModuleNotFoundError 를 일으킵니다. 만약 모듈 이름이 없다면, 파이썬은 모듈 검색을 계속 진행합니다.

sys.modules 은 쓰기가 허락됩니다. 키를 삭제해도 해당 모듈을 파괴하지는 않지만(다른 모듈들이 아직 그 모듈에 대한 참조를 유지하고 있을 수 있으므로), 해당 이름의 모듈에 대한 캐시를 무효화해서, 다음 임포트때 파이썬으로 하여금 그 모듈을 다시 찾도록 만듭니다. 키에는 None 을 대입할 수도 있는데, 다음 임포트 때 ModuleNotFoundError 가 일어나도록 만듭니다.

모듈 객체에 대한 참조를 유지한다면, sys.modules 의 캐시 항목을 무효로 한 후 다시 임포트하면 두 모듈 객체는 같은 것이 아니게 됨에 주의해야 합니다. 반면에 importlib.reload() 는 같은 모듈 객체를 재사용하고, 간단하게 모듈의 코드를 다시 실행해서 모듈의 내용을 다시 초기화합니다.

5.3.2. 파인더(finder)와 로더(loader)

모듈이 sys.modules 에서 발견되지 않으면, 모듈을 찾아서 로드하기 위해 파이썬의 임포트 프로토콜이 구동됩니다. 이 프로토콜은 두 개의 개념적 객체들로 구성되어 있습니다, 파인더 와 로더. 파인더의 일은 자신이 알고 있는 전략을 사용해, 주어진 이름의 모듈을 찾을 수 있는지 결정하는 것입니다. 두 인터페이스 모두를 구현한 객체들을 임포터라고 부릅니다 - 요청한 모듈을 로딩할 수 있다고 판단할 때 자신을 돌려줍니다.

파이썬은 여러 가지 기본 파인더들과 임포터들을 포함하고 있습니다. 첫 번째 것은 내장 모듈들의 위치를 찾을 수 있고, 두 번째 것은 프로즌 모듈(frozen module)의 위치를 찾을 수 있고, 세 번째 것은 모듈을 임포트 경로 에서 검색합니다. 임포트 경로 는 파일 시스템의 경로나 zip 파일을 가리키는 위치들의 목록입니다. 그것은 URL로 식별될 수 있는 것들처럼, 위치가 지정될 수 있는 자원들을 검색하도록 확장될 수 있습니다.

임포트 절차는 확장 가능해서, 모듈 검색의 범위를 확대하기 위해 새 파인더를 추가할 수 있습니다.

파인더는 실제로 모듈을 로드하지는 않습니다. 주어진 이름의 모듈을 찾으면 임포트와 관련된 정보들을 요약한 모듈 스펙 (module spec) 을 돌려주는데, 임포트 절차는 모듈을 로딩할 때 이것을 사용하게 됩니다.

다음 섹션은 파인더와 로더의 프로토콜에 대해 좀 더 자세히 설명하는데, 임포트 절차를 확장하기 위해 어떻게 새로운 것들을 만들고 등록하는지를 포함합니다.

버전 3.4에서 변경: 이전 버전의 파이썬에서, 파인더가 로더 를 직접 돌려주었지만, 이제는 로더를 포함하고 있는 모듈 스펙을 돌려줍니다. 임포트 도중 로더가 아직 사용되기는 하지만 그 역할은 축소되었습니다.

5.3.3. 임포트 훅(import hooks)

임포트 절차는 확장할 수 있도록 설계되었습니다; 일차적인 메커니즘은 임포트 훅(import hook) 입니다. 두 가지 종류의 임포트 훅이 있습니다: 메타 훅(meta hook) 과 임포트 경로 훅(import path hook).

메타 훅은 임포트 처리의 처음에, sys.modules 캐시 조회를 제외한 다른 임포트 처리들이 시작되기 전에 호출됩니다. 이것은 메타 훅이 sys.path 처리, 프로즌 모듈, 내장 모듈들을 재정의할 수 있게 합니다. 다음에 설명하듯이, 메타 훅은 sys.meta_path 에 새 파인더 객체를 추가하는 방법으로 등록할 수 있습니다.

임포트 경로 훅은 sys.path (혹은 package.__path__) 처리 일부로, 관련된 경로 항목을 만나는 시점에 호출됩니다. 다음에 설명하듯이, 임포트 경로 훅은 sys.path_hooks 에 새 콜러블을 추가하는 방법으로 등록할 수 있습니다.

5.3.4. 메타 경로(meta path)

When the named module is not found in sys.modules, Python next searches sys.meta_path, which contains a list of meta path finder objects. These finders are queried in order to see if they know how to handle the named module. Meta path finders must implement a method called find_spec() which takes three arguments: a name, an import path, and (optionally) a target module. The meta path finder can use any strategy it wants to determine whether it can handle the named module or not.

만약 메타 경로 파인더가 주어진 이름의 모듈을 처리하는 법을 안다면, 스펙 객체를 돌려줍니다. 그럴 수 없다면 None 을 돌려줍니다. 만약 sys.meta_path 처리가 스펙을 돌려주지 못하고 목록의 끝에 도달하면, ModuleNotFoundError 를 일으킵니다. 발생하는 다른 예외들은 그냥 확산시키고, 임포트 프로세스를 중단합니다.

The find_spec() method of meta path finders is called with two or three arguments. The first is the fully qualified name of the module being imported, for example foo.bar.baz. The second argument is the path entries to use for the module search. For top-level modules, the second argument is None, but for submodules or subpackages, the second argument is the value of the parent package’s __path__ attribute. If the appropriate __path__ attribute cannot be accessed, a ModuleNotFoundError is raised. The third argument is an existing module object that will be the target of loading later. The import system passes in a target module only during reload.

메타 경로는 한 번의 임포트 요청에 대해 여러 번 탐색 될 수 있습니다. 예를 들어, 대상 모듈들이 아무것도 캐싱 되지 않았다고 할 때, foo.bar.baz 를 임포트 하려면, 먼저 각 메타 경로 파인더 (mpf)들에 대해 mpf.find_spec("foo", None, None) 를 호출해서 최상위 임포트를 수행합니다. foo 가 임포트 된 후에, 메타 경로를 두 번째 탐색해서 foo.bar 를 임포트 하는데, mpf.find_spec("foo.bar", foo.__path__, None) 를 호출합니다. 일단 foo.bar 가 임포트 되면, 마지막 탐색은 mpf.find_spec("foo.bar.baz", foo.bar.__path__, None) 를 호출합니다.

어떤 메타 경로 파인더들은 오직 최상위 임포트만 지원합니다. 이런 임포터들은 두 번째 인자로 None 이 아닌 것이 오면 항상 None 을 돌려줍니다.

파이썬의 기본 sys.meta_path 는 세 개의 메타 경로 파인더를 갖고 있습니다. 하나는 내장 모듈을 임포트하는 법을 알고, 하나는 프로즌 모듈을 임포트하는 법을 알고, 하나는 임포트 경로 에서 모듈을 임포트하는 법을 압니다(즉 경로 기반 파인더).

버전 3.4에서 변경: The find_spec() method of meta path finders replaced find_module(), which is now deprecated. While it will continue to work without change, the import machinery will try it only if the finder does not implement find_spec().

버전 3.10에서 변경: Use of find_module() by the import system now raises ImportWarning.

버전 3.12에서 변경: find_module() has been removed. Use find_spec() instead.

5.4. 로딩(loading)

모듈 스펙이 발견되면, 임포트 절차는 모듈을 로딩할 때 그것(그것이 가진 로더도)을 사용합니다. 여기에 임포트의 로딩 과정 동안 일어나는 일에 대한 대략적인 그림이 있습니다:

module = None
if spec.loader is not None and hasattr(spec.loader, 'create_module'):
    # It is assumed 'exec_module' will also be defined on the loader.
    module = spec.loader.create_module(spec)
if module is None:
    module = ModuleType(spec.name)
# The import-related module attributes get set here:
_init_module_attrs(spec, module)

if spec.loader is None:
    # unsupported
    raise ImportError
if spec.origin is None and spec.submodule_search_locations is not None:
    # namespace package
    sys.modules[spec.name] = module
elif not hasattr(spec.loader, 'exec_module'):
    module = spec.loader.load_module(spec.name)
else:
    sys.modules[spec.name] = module
    try:
        spec.loader.exec_module(module)
    except BaseException:
        try:
            del sys.modules[spec.name]
        except KeyError:
            pass
        raise
return sys.modules[spec.name]

다음과 같은 세부 사항에 주의해야 합니다:

만약 주어진 이름의 모듈이 sys.modules 에 있다면, 임포트는 이미 그걸 돌려줄 겁니다.

로더가 모듈을 실행하기 전에 모듈은 sys.modules 에 자리를 잡습니다. 이것은 필수적인데 모듈이 (직접적 혹은 간접적으로) 자신을 임포트 할 수 있기 때문입니다; 먼저 sys.modules 에 추가함으로써 최악의 상황에 제한 없는 재귀(recursion)를 방지하고, 최선의 상황에 여러 번 로딩되는 것을 막습니다.

로딩이 실패하면, 실패한 모듈(오직 실패한 모듈만)은 sys.modules 에서 삭제됩니다. sys.modules 캐시에 이미 있는 모듈과 부수적 효과로 성공적으로 로딩된 모듈들은 캐시에 남아있어야만 합니다. 이는 실패한 모듈조차 sys.modules 에 남아있게 되는 리로딩과 대비됩니다.

모듈이 만들어졌지만, 아직 실행되기 전에, 뒤의 섹션 에서 요약되듯이, 임포트 절차는 임포트 관련 모듈 어트리뷰트들을 설정합니다(위의 의사 코드 예에서 “_init_module_attrs”).

모듈 실행은 로딩에서 모듈의 이름 공간이 채워지는 결정적 순간입니다. 실행은 전적으로 로더에 위임되는데, 로더가 어떤 것이 어떻게 채워져야 하는지 결정합니다.

로딩 동안 만들어지고 exec_module() 로 전달되는 모듈은 임포트의 끝에 반환되는 것이 아닐 수 있습니다 [2].

버전 3.4에서 변경: 임포트 시스템이 기초 공사에 대한 로더의 책임을 들고 갔습니다. 이것들은 전에는 importlib.abc.Loader.load_module() 메서드에서 수행되었습니다.

5.4.1. 로더

모듈 로더는 로딩의 결정적인 기능을 제공합니다: 모듈 실행. 임포트 절차는 하나의 인자로 importlib.abc.Loader.exec_module() 메서드를 호출하는데, 실행할 모듈 객체가 전달됩니다. exec_module() 이 돌려주는 값은 무시됩니다.

로더는 다음과 같은 요구 조건들을 만족해야 합니다:

만약 모듈이 파이썬 모듈(내장 모듈이나 동적으로 로딩되는 확장이 아니라)이면, 로더는 모듈의 코드를 모듈의 전역 이름 공간(module.__dict__)에서 실행해야 합니다.

만약 로더가 모듈을 실행하지 못하면, ImportError 를 일으켜야 합니다. 하지만 exec_module() 동안 발생하는 다른 예외도 전파됩니다.

많은 경우에, 파인더와 로더는 같은 객체입니다; 그런 경우 find_spec() 메서드는 로더가 self 로 설정된 스펙을 돌려줍니다.

모듈 로더는 create_module() 메서드를 구현함으로써 로딩하는 동안 모듈 객체를 만드는 일에 개입할 수 있습니다. 하나의 인자, 모듈 스펙, 을 받아들이고 로딩 중 사용할 모듈 객체를 돌려줍니다. create_module() 은 모듈 객체의 어트리뷰트를 설정할 필요는 없습니다. 만약 메서드가 None 을 돌려주면, 임포트 절차는 새 모듈을 스스로 만듭니다.

Added in version 3.4: 로더의 create_module() 메서드.

버전 3.4에서 변경: load_module() 메서드는 exec_module() 로 대체되었고, 임포트 절차가 로딩의 공통 코드(boilerplate)에 대한 책임을 집니다.

이미 존재하는 로더들과의 호환을 위해, 임포트 절차는 load_module() 메서드가 존재하고, exec_module() 을 구현하지 않았으면 load_module() 을 사용합니다. 하지만 load_module() 은 폐지되었습니다. 로더는 대신 exec_module() 를 구현해야 합니다.

load_module() 메서드는 모듈을 실행하는 것 외에 위에서 언급한 모든 공통(boilerplate) 로딩 기능을 구현해야만 합니다. 같은 제약들이 모두 적용되는데, 추가적인 설명을 붙여보면:

만약 sys.modules 에 주어진 이름의 모듈 객체가 이미 존재하면, 로더는 반드시 그 객체를 사용해야 합니다. (그렇지 않으면, importlib.reload() 이 올바로 동작하지 않게 됩니다.) 만약 sys.modules 에 주어진 이름의 모듈이 없으면, 로더는 새 모듈객체를 만들고 sys.modules 에 추가해야 합니다.

제한 없는 재귀와 여러 번 로딩되는 것을 방지하기 위해, 로더가 모듈 코드를 실행하기 전에 모듈이 sys.modules 에 존재해야 합니다.

만약 로딩이 실패하면, 로더는 sys.modules 에 삽입한 모듈들을 제거해야 하는데, 실패한 모듈만을 제거해야 하고, 로더가 그 모듈을 직접 명시적으로 로드한 경우에만 그래야 합니다.

버전 3.5에서 변경: exec_module() 이 정의되었지만 create_module() 이 정의되지 않으면 DeprecationWarning 이 발생합니다.

버전 3.6에서 변경: exec_module() 이 정의되었지만 create_module() 이 정의되지 않으면 ImportError 를 일으킵니다.

버전 3.10에서 변경: Use of load_module() will raise ImportWarning.

5.4.2. 서브 모듈

어떤 메커니즘으로든 (예를 들어, importlib API들, import 나 import-from 문, 내장 __import__()) 서브 모듈이 로드될 때, 서브 모듈 객체로의 연결은 부모 모듈의 이름 공간에 이루어집니다. 예를 들어, 패키지 spam 이 서브 모듈 foo 를 가지면, spam.foo 를 임포트 한 후에는 spam 이 서브 모듈에 연결된 어트리뷰트 foo 를 갖게 됩니다. 다음과 같은 디렉터리 구조로 되어 있다고 합시다:

spam/
    __init__.py
    foo.py

and spam/__init__.py has the following line in it:

from .foo import Foo

then executing the following puts name bindings for foo and Foo in the spam module:

>>> import spam
>>> spam.foo
<module 'spam.foo' from '/tmp/imports/spam/foo.py'>
>>> spam.Foo
<class 'spam.foo.Foo'>

파이썬의 익숙한 이름 연결 규칙에서 볼 때 의외의 결과로 보일 수 있습니다. 하지만 실제로는 임포트 시스템의 근본적인 기능입니다. 불변의 규칙은 이렇습니다: 만약 sys.modules['spam'] 과 sys.modules['spam.foo'] 가 있다면 (위의 임포트 이후의 상태가 그러합니다), 뒤에 있는 것은 반드시 앞에 있는 것의 foo 어트리뷰트가 되어야 합니다.

5.4.3. Module specs

임포트 절차는 임포트 동안 각 모듈에 대한 다양한 정보들을 사용합니다, 특히 로딩 전에. 대부분 정보는 모든 모듈의 공통이다. 모듈 스펙의 목적은 이 임포트 관련 정보를 모듈별로 요약하는 것입니다.

임포트 동안 스펙을 사용하면 상태가 임포트 시스템의 구성 요소들로 전달될 수 있습니다, 예를 들어 모듈 스펙을 만드는 파인더와 그것을 실행하는 로더 간에. 가장 중요한 것은, 임포트 절차가 로딩의 공통 연산(boilerplate operation)을 수행할 수 있도록 하는 것입니다. 모듈 스펙이 없다면 로더가 모든 책임을 지게 됩니다.

The module’s spec is exposed as module.__spec__. Setting __spec__ appropriately applies equally to modules initialized during interpreter startup. The one exception is __main__, where __spec__ is set to None in some cases.

See ModuleSpec for details on the contents of the module spec.

Added in version 3.4.

5.4.4. __path__ attributes on modules

The __path__ attribute should be a (possibly empty) sequence of strings enumerating the locations where the package’s submodules will be found. By definition, if a module has a __path__ attribute, it is a package.

A package’s __path__ attribute is used during imports of its subpackages. Within the import machinery, it functions much the same as sys.path, i.e. providing a list of locations to search for modules during import. However, __path__ is typically much more constrained than sys.path.

The same rules used for sys.path also apply to a package’s __path__. sys.path_hooks (described below) are consulted when traversing a package’s __path__.

A package’s __init__.py file may set or alter the package’s __path__ attribute, and this was typically the way namespace packages were implemented prior to PEP 420 [https://peps.python.org/pep-0420/]. With the adoption of PEP 420 [https://peps.python.org/pep-0420/], namespace packages no longer need to supply __init__.py files containing only __path__ manipulation code; the import machinery automatically sets __path__ correctly for the namespace package.

5.4.5. 모듈 repr

기본적으로, 모든 모듈은 사용할만한 repr 을 갖고 있습니다. 하지만 위의 어트리뷰트들과 모듈 스펙에 있는 것들에 따라, 모듈 객체의 repr 을 좀 더 명시적으로 제어할 수 있습니다.

모듈이 스펙(__spec__)을 가지면, 임포트 절차는 그것으로부터 repr 을 만들려고 시도합니다. 그것이 실패하거나 스펙이 없으면, 임포트 시스템은 모듈에서 제공되는 것들로 기본 repr 을 구성합니다. module.__name__, module.__file__, module.__loader__ 을 repr 의 입력으로 사용하려고 시도하는데, 빠진 정보는 기본값으로 채웁니다.

사용되고 있는 정확한 규칙은 이렇습니다:

모듈이 __spec__ 어트리뷰트를 가지면, 스펙에 있는 정보로 repr 을 생성합니다. “name”, “loader”, “origin”, “has_location” 어트리뷰트들이 사용됩니다.

모듈이 __file__ 어트리뷰트를 가지면, 모듈의 repr 의 일부로 사용됩니다.

모듈이 __file__ 어트리뷰트를 갖지 않지만 None 이 아닌 __loader__ 를 가지면, 로더의 repr 이 모듈의 repr 의 일부로 사용됩니다.

그렇지 않으면, repr 에 모듈의 __name__ 을 사용합니다.

버전 3.12에서 변경: Use of module_repr(), having been deprecated since Python 3.4, was removed in Python 3.12 and is no longer called during the resolution of a module’s repr.

5.4.6. 캐시된 바이트 코드 무효화

파이썬이 .pyc 파일로부터 캐시 된 바이트 코드를 로드하기 전에, 캐시가 최신 버전인지 소스 .py 파일과 비교합니다. 기본적으로, 파이썬은 소스의 최종 수정 타임스탬프와 크기를 캐시 파일을 만들 때 함께 저장해서 이 작업을 수행합니다. 실행시간에, 임포트 시스템은 캐시 파일에 저장된 메타 데이터를 소스의 메타 데이터와 대조하여 캐시 파일의 유효성을 검사합니다.

파이썬은 또한 “해시 기반” 캐시 파일을 지원하는데, 캐시 파일은 메타 데이터 대신에 소스 파일의 내용 해시를 저장합니다. 해시 기반 .pyc 파일에는 두 가지 변종이 있습니다: 검사형(checked)과 비검사형(unchecked). 검사형 해시 기반 .pyc 파일의 경우, 파이썬은 소스 파일을 해시하고 결과 해시를 캐시 파일의 해시와 비교하여 캐시 파일의 유효성을 검사합니다. 검사형 해시 기반 캐시 파일이 유효하지 않은 것으로 판명되면, 파이썬은 캐시 파일을 다시 생성하고 새로운 검사형 해시 기반 캐시 파일을 만듭니다. 비검사형 해시 기반 .pyc 파일의 경우, 파이썬은 단순히 캐시 파일이 존재할 경우 유효하다고 가정합니다. 해시 기반 .pyc 파일 유효성 검사 동작은 --check-hash-based-pycs 플래그로 재정의될 수 있습니다.

버전 3.7에서 변경: 해시 기반 .pyc 파일을 추가했습니다. 이전에는, 파이썬은 바이트 코드 캐시의 타임스탬프 기반 무효화만 지원했습니다.

5.5. 경로 기반 파인더

앞에서 언급했듯이, 파이썬은 여러 기본 메타 경로 파인더들을 갖고 있습니다. 이 중 하나는, 경로 기반 파인더 (PathFinder) 로 불리는데, 경로 엔트리 들의 목록을 담고 있는 임포트 경로 를 검색합니다. 각 경로 엔트리는 모듈을 찾을 곳을 가리킵니다.

경로 기반 파인더 자신은 뭔가를 임포트하는 법에 대해서는 아는 것이 없습니다. 대신에, 각 경로 엔트리를 탐색하면서, 각각을 구체적인 경로 엔트리를 다루는 법을 아는 경로 엔트리 파인더와 관련시킵니다.

경로 엔트리 파인더의 기본 집합은 파일 시스템에서 모듈을 찾는데 필요한 모든 개념을 구현하는데, 파이썬 소스 코드(.py 파일들), 파이썬 바이트 코드(.pyc 파일들), 공유 라이브러리(예를 들어 .so 파일들)와 같은 특수 파일형들을 처리합니다. 표준라이브러리의 zipimport 모듈의 지원을 받으면, 기본 경로 엔트리 파인더는 이 모든 파일(공유 라이브러리를 제외한 것들)을 zip 파일들로부터 로딩합니다.

경로 엔트리가 파일 시스템의 위치로 제한될 필요는 없습니다. URL이나 데이터베이스 조회나 문자열로 지정될 수 있는 어떤 위치도 가능합니다.

경로 기반 파인더는 검색 가능한 경로 엔트리의 유형을 확장하고 커스터마이즈할 수 있도록 하는 추가의 훅과 프로토콜을 제공합니다. 예를 들어, 네트워크 URL을 경로 엔트리로 지원하고 싶다면, 웹에서 모듈을 찾는 HTTP 개념을 구현하는 훅을 작성할 수 있습니다. 이 훅 (콜러블)은 아래에서 설명하는 프로토콜을 지원하는 경로 엔트리 파인더 를 돌려주는데, 웹에 있는 모듈을 위한 로더를 얻는 데 사용됩니다.

경고의 글: 이 섹션과 앞에 나온 것들은 모두 파인더라는 용어를 사용하는데, 메타 경로 파인더 와 경로 엔트리 파인더 라는 용어를 사용해서 구분합니다. 이 두 종류의 파인더는 매우 유사해서 비슷한 프로토콜을 지원하고 임포트 절차에서 비슷한 방식으로 기능합니다. 하지만 이것들이 미묘하게 다르다는 것을 기억하는 것이 중요합니다. 특히, 메타 경로 파인더는 임포트 절차의 처음에 개입하는데, sys.meta_path 탐색을 통해 들어옵니다.

반면에, 경로 엔트리 파인더는 경로 기반 파인더의 구현 상세인데, 사실 경로 기반 파인더가 sys.meta_path 로 부터 제거되면, 경로 엔트리 파인더의 개념은 일절 호출되지 않습니다.

5.5.1. 경로 엔트리 파인더

경로 기반 파인더 는 위치가 문자열 경로 엔트리 로 지정된 파이썬 모듈과 패키지를 찾고 로드하는 책임을 집니다. 대부분의 경로 엔트리는 파일 시스템의 위치를 가리키지만, 이것으로 한정될 필요는 없습니다.

메타 경로 파인더로서, 경로 기반 파인더 는 앞에서 설명한 find_spec() 프로토콜을 구현합니다. 하지만 모듈이 임포트 경로 에서 어떻게 발견되고 로드되는지는 커스터마이즈하는데 사용될 수 있는 추가의 훅을 제공합니다.

경로 기반 파인더 는 세 개의 변수를 사용합니다, sys.path, sys.path_hooks, sys.path_importer_cache. 패키지 객체의 __path__ 어트리뷰트 또한 사용된다. 이것들은 임포트 절차를 커스터마이즈할 수 있는 추가의 방법을 제공합니다.

sys.path contains a list of strings providing search locations for modules and packages. It is initialized from the PYTHONPATH environment variable and various other installation- and implementation-specific defaults. Entries in sys.path can name directories on the file system, zip files, and potentially other “locations” (see the site module) that should be searched for modules, such as URLs, or database queries. Only strings should be present on sys.path; all other data types are ignored.

경로 기반 파인더 는 메타 경로 파인더 이기 때문에, 앞에서 설명했듯이 임포트 절차는 경로 기반 파인더의 find_spec() 메서드를 호출하는 것으로 임포트 경로 검색을 시작합니다. find_spec() 에 제공되는 path 인자는 탐색할 문자열 경로들의 리스트입니다 - 보통 패키지 내에서 임포트 하면 패키지의 __path__ 어트리뷰트. path 인자가 None 이면, 최상위 임포트를 뜻하고 sys.path 가 사용됩니다.

The path based finder iterates over every entry in the search path, and for each of these, looks for an appropriate path entry finder (PathEntryFinder) for the path entry. Because this can be an expensive operation (e.g. there may be stat() call overheads for this search), the path based finder maintains a cache mapping path entries to path entry finders. This cache is maintained in sys.path_importer_cache (despite the name, this cache actually stores finder objects rather than being limited to importer objects). In this way, the expensive search for a particular path entry location’s path entry finder need only be done once. User code is free to remove cache entries from sys.path_importer_cache forcing the path based finder to perform the path entry search again.

경로 엔트리가 캐시에 없으면, 경로 기반 파인더는 sys.path_hooks 에 있는 모든 콜러블들을 탐색합니다. 이 목록의 각 경로 엔트리 훅 은 검색할 경로 엔트리 인자 한 개를 사용해서 호출됩니다. 이 콜러블은 경로 엔트리를 다룰 수 있는 경로 엔트리 파인더 를 돌려주거나, ImportError 를 발생시킬 수 있습니다. ImportError 는 경로 기반 파인더가 어떤 훅이 주어진 경로 엔트리 를 위한 경로 엔트리 파인더 를 발견할 수 없음을 알리는 데 사용합니다. 이 예외는 무시되고 임포트 경로 탐색은 계속됩니다. 훅은 문자열이나 바이트열을 기대해야 합니다; 바이트열의 인코딩은 훅이 결정하고(예를 들어, 파일 시스템 인코딩이나 UTF-8 이나 그 밖의 다른 것일 수 있습니다), 만약 훅이 인자를 디코딩할 수 없으면 ImportError 를 일으켜야 합니다.

만약 sys.path_hooks 탐색이 아무런 경로 엔트리 파인더 를 돌려주지 못하면, 경로 기반 파인더의 find_spec() 메서드는 sys.path_importer_cache 에 None 을 저장하고(이 경로 엔트리를 위한 파인더가 없음을 가리키기 위해), None 을 돌려줘서 이 메타 경로 파인더 가 모듈을 찾을 수 없음을 알립니다.

만약 sys.path_hooks 에 있는 어느 하나의 경로 엔트리 훅 콜러블이 경로 엔트리 파인더 를 돌려주면, 파인더에 모듈 스펙을 요청하기 위해 다음에 나오는 프로토콜이 사용됩니다. 모듈 스펙은 모듈을 로딩할 때 사용됩니다.

현재 작업 디렉터리(current working directory) – 빈 문자열로 표현된다 – 는 sys.path 에 있는 다른 엔트리들과 약간 다르게 취급됩니다. 첫째로, 현재 작업 디렉터리가 존재하지 않음이 발견되면 sys.path_importer_cache 에는 아무런 값도 저장되지 않습니다. 둘째로, 현재 작업 디렉터리는 각 모듈 조회 때마다 다시 확인됩니다. 셋째로, sys.path_importer_cache 에 사용되는 경로와 importlib.machinery.PathFinder.find_spec() 가 돌려주는 경로는 빈 문자열이 아니라 실제 현재 작업 디렉터리가 됩니다.

5.5.2. 경로 엔트리 파인더 프로토콜

모듈과 초기화된 패키지의 임포트를 지원하고 이름 공간 패키지에 포션으로 이바지하기 위해, 경로 엔트리 파인더는 find_spec() 메서드를 구현해야 합니다.

find_spec() 은 두 개의 인자를 받아들입니다: 임포트 할 모듈의 완전히 정규화된 이름과 (생략 가능한) 타깃 모듈. find_spec() 은 값이 완전히 채워진 모듈의 스펙을 돌려줍니다. 이 스펙은 항상 “loader” 가 설정됩니다(한가지 예외가 있습니다).

To indicate to the import machinery that the spec represents a namespace portion, the path entry finder sets submodule_search_locations to a list containing the portion.

버전 3.4에서 변경: find_spec() replaced find_loader() and find_module(), both of which are now deprecated, but will be used if find_spec() is not defined.

예전의 경로 엔트리 파인더는 find_spec() 대신에 이 두 개의 폐지된 메서드들을 구현할 수 있습니다. 이 메서드들은 과거 호환성 때문에 아직도 사용됩니다. 하지만, find_spec() 이 경로 엔트리 파인더에 구현되면, 예전 메서드들은 무시됩니다.

find_loader() takes one argument, the fully qualified name of the module being imported. find_loader() returns a 2-tuple where the first item is the loader and the second item is a namespace portion.

임포트 프로토콜의 다른 구현들과의 과거 호환성을 위해, 많은 경로 엔트리 파인더들은 메타 경로 파인더가 지원하는 것과 같고 전통적인 find_module() 메서드 또한 지원합니다. 하지만 경로 엔트리 파인더 find_module() 메서드는 결코 path 인자로 호출되지 않습니다 (그것들은 경로 훅의 최초 호출 때 적절한 경로 정보를 기록해둘 것으로 기대됩니다).

경로 엔트리 파인더의 find_module() 메서드는 경로 엔트리 파인더가 이름 공간 패키지에 포션으로 이바지하는 것을 허락하지 않기 때문에 폐지되었습니다. 만약 경로 엔트리 파인더에 find_loader() 와 find_module() 이 모두 존재하면, 임포트 시스템은 항상 find_module() 대신 find_loader() 를 호출합니다.

버전 3.10에서 변경: Calls to find_module() and find_loader() by the import system will raise ImportWarning.

버전 3.12에서 변경: find_module() and find_loader() have been removed.

5.6. 표준 임포트 시스템 교체하기

임포트 시스템 전체를 교체하기 위한 가장 신뢰성 있는 메커니즘은 sys.meta_path 의 기본값들을 모두 삭제하고, 새로 만든 메타 경로 훅들로 채우는 것입니다.

만약 임포트 시스템을 액세스하는 다른 API들에 영향을 주지 않고, 단지 임포트 문의 동작만을 변경해도 좋다면, 내장 __import__() 함수를 교체하는 것으로 충분할 수도 있습니다. 이 기법은 특정 모듈 내에서의 임포트 문의 동작만을 변경하도록 모듈 수준에서 적용될 수도 있습니다.

메타 경로의 앞쪽에 있는 훅에서 어떤 모듈의 임포트를 선택적으로 막으려면(표준 임포트 시스템을 완전히 비활성화하는 대신), find_spec() 에서 None 을 돌려주는 대신, ModuleNotFoundError 를 일으키는 것으로 충분합니다. 전자는 메타 경로 검색을 계속해야 한다는 것을 지시하는 반면, 예외를 일으키면 즉시 종료시킵니다.

5.7. 패키지 상대 임포트

상대 임포트는 선행 점을 사용합니다. 단일 선행 점은 현재 패키지에서 시작하는 상대 임포트를 나타냅니다. 두 개 이상의 선행 점은 현재 패키지의 부모(들)에 대한 상대 임포트를 나타내며, 첫 번째 점 다음의 점 하나당 하나의 수준을 나타냅니다. 예를 들어, 다음과 같은 패키지 배치가 제공될 때:

package/
    __init__.py
    subpackage1/
        __init__.py
        moduleX.py
        moduleY.py
    subpackage2/
        __init__.py
        moduleZ.py
    moduleA.py

subpackage1/moduleX.py나 subpackage1/__init__.py 모두에서, 다음은 유효한 상대 임포트입니다:

from .moduleY import spam
from .moduleY import spam as ham
from . import moduleY
from ..subpackage1 import moduleY
from ..subpackage2.moduleZ import eggs
from ..moduleA import foo

절대 임포트는 import <> 또는 from <> import <> 문법을 사용할 수 있지만, 상대 임포트는 두 번째 형식만 사용할 수 있습니다; 그 이유는:

import XXX.YYY.ZZZ

가 XXX.YYY.ZZZ를 사용할 수 있는 표현식으로 노출하지만, .moduleY는 유효한 표현식이 아니기 때문입니다.

5.8. __main__ 에 대한 특별한 고려

__main__ 모듈은 파이썬의 임포트 시스템에서 특별한 경우입니다. 다른 곳에서 언급했듯이, __main__ 모듈은 sys 와 builtins 처럼 인터프리터 시작 때 직접 초기화됩니다. 하지만, 이 두 개와는 다르게, 이것은 엄밀하게 내장 모듈로 취급되지 않습니다. 이것은 __main__ 이 초기화되는 방식이 인터프리터를 실행할 때 주는 플래그와 다른 옵션들에 영향을 받기 때문입니다.

5.8.1. __main__.__spec__

__main__ 이 어떻게 초기화되는지에 따라, __main__.__spec__ 은 적절히 설정되기도 하고 None 으로 설정되기도 합니다.

파이썬이 -m 옵션으로 시작하면, __spec__ 은 해당하는 모듈이나 패키지의 모듈 스팩으로 설정됩니다. 또한 __spec__ 은 __main__ 모듈이 디렉터리나 zip 파일이나 다른 sys.path 엔트리를 실행하는 일부로 로드될 때 그 내용이 채워집니다.

나머지 경우 에는 __main__.__spec__ 은 None 으로 설정되는데, __main__ 을 채우는데 사용된 코드가 임포트 가능한 모듈에 직접 대응하지 않기 때문입니다:

대화형 프롬프트

-c 옵션

표준 입력으로 실행

소스 파일이나 바이트 코드 파일로부터 직접 실행

마지막 경우에 __main__.__spec__ 이 항상 None 임에 주의해야 합니다. 설사 그 파일이 기술적으로 모듈로 임포트 될 수 있어도 그렇습니다. __main__ 에 올바른 모듈 메타데이터가 필요하다면 -m 스위치를 사용해야 합니다.

또한 __main__ 이 임포트 가능한 모듈에 대응되고, __main__.__spec__ 이 적절히 설정되었다 하더라도, 이 둘은 여전히 다른 모듈로 취급됨에 주의해야 합니다. 이것은 if __name__ == "__main__": 검사로 둘러싸인 블록이 모듈이 __main__ 이름 공간을 채울 때만 실행되고, 일반적인 임포트 때는 실행되지 않는다는 사실 때문입니다.

5.9. 참고문헌

임포트 절차는 파이썬의 초창기부터 상당히 변해왔습니다. 문서를 작성한 이후에 약간의 세부사항이 변경되었기는 하지만, 최초의 패키지 규격 [https://www.python.org/doc/essays/packages/] 은 아직 읽을 수 있도록 남아있습니다.

sys.meta_path 의 최초 규격은 PEP 302 [https://peps.python.org/pep-0302/] 이고, 뒤이은 확장은 PEP 420 [https://peps.python.org/pep-0420/] 입니다.

PEP 420 [https://peps.python.org/pep-0420/] introduced namespace packages for Python 3.3. PEP 420 [https://peps.python.org/pep-0420/] also introduced the find_loader() protocol as an alternative to find_module().

PEP 366 [https://peps.python.org/pep-0366/] 은 메인 모듈에서의 명시적인 상태 임포트를 위한 __package__ 어트리뷰트의 추가에 관해 설명하고 있습니다.

PEP 328 [https://peps.python.org/pep-0328/] 은 절대와 명시적인 상대 임포트들 도입하고 PEP 366 [https://peps.python.org/pep-0366/] 이 결국 __package__ 를 지정하게 되는 개념을 초기에 __name__ 으로 제안했습니다.

PEP 338 [https://peps.python.org/pep-0338/] 은 모듈을 스크립트로 실행하는 것을 정의합니다.

PEP 451 [https://peps.python.org/pep-0451/] 은 스팩 객체에 모듈별 임포트 상태를 요약하는 것을 추가합니다. 로더들에 주어졌던 대부분의 공통 코드 책임들을 임포트 절차로 옮기기도 했습니다. 이 변경은 임포트 시스템의 여러 API 들을 폐지하도록 만들었고, 파인더와 로더에 새 메서드들을 추가하기도 했습니다.

각주

[1]

types.ModuleType 을 보세요.

[2]

importlib 구현은 반환 값을 직접 사용하지 않습니다. 대신에, sys.modules 에서 모듈 이름을 조회해서 모듈을 얻습니다. 이것의 간접적인 효과는 임포트되는 모듈이 sys.modules 에 있는 자신을 바꿀 수 있다는 것입니다. 이것은 구현 상세 동작이고 다른 파이썬 구현에서 동작한다고 보장되지 않습니다.

6. 표현식

이 장은 파이썬에서 사용되는 표현식 요소들의 의미를 설명합니다.

문법 유의 사항: 여기와 이어지는 장에서는, 어휘 분석이 아니라 문법을 설명하기 위해 확장 BNF 표기법을 사용합니다. 문법 규칙이 다음과 같은 형태를 가지고,

name ::=  othername

뜻(semantics)을 주지 않으면, 이 형태의 name 의 뜻은 othername 과 같습니다.

6.1. 산술 변환

When a description of an arithmetic operator below uses the phrase “the numeric arguments are converted to a common real type”, this means that the operator implementation for built-in types works as follows:

If both arguments are complex numbers, no conversion is performed;

if either argument is a complex or a floating-point number, the other is converted to a floating-point number;

그렇지 않으면, 두 인자는 모두 정수여야 하고, 변환은 필요 없습니다.

어떤 연산자들(예를 들어, ‘%’ 연산자의 왼쪽 인자로 주어지는 문자열)에 대해서는 몇 가지 추가의 규칙이 적용됩니다. 확장(extension)은 그들 자신의 변환 규칙을 정의해야 합니다.

6.2. 아톰 (Atoms)

아톰은 표현식의 가장 기본적인 요소입니다. 가장 간단한 아톰은 식별자와 리터럴입니다. 괄호, 대괄호, 중괄호로 둘러싸인 형태도 문법적으로 아톰으로 분류됩니다. 아톰의 문법은 이렇습니다:

atom      ::=  identifier | literal | enclosure
enclosure ::=  parenth_form | list_display | dict_display | set_display
               | generator_expression | yield_atom

6.2.1. 식별자 (이름)

아톰으로 등장하는 식별자는 이름입니다. 어휘 정의에 대해서는 식별자와 키워드 섹션을, 이름과 연결에 대한 문서는 이름과 연결(binding) 섹션을 보세요.

이름이 객체에 연결될 때, 아톰의 값을 구하면 객체가 나옵니다. 이름이 연결되지 않았을 때, 값을 구하려고 하면 NameError 예외가 일어납니다.

6.2.1.1. Private name mangling

When an identifier that textually occurs in a class definition begins with two or more underscore characters and does not end in two or more underscores, it is considered a private name of that class.

더 보기

The class specifications.

More precisely, private names are transformed to a longer form before code is generated for them. If the transformed name is longer than 255 characters, implementation-defined truncation may happen.

The transformation is independent of the syntactical context in which the identifier is used but only the following private identifiers are mangled:

Any name used as the name of a variable that is assigned or read or any name of an attribute being accessed.

The __name__ attribute of nested functions, classes, and type aliases is however not mangled.

The name of imported modules, e.g., __spam in import __spam. If the module is part of a package (i.e., its name contains a dot), the name is not mangled, e.g., the __foo in import __foo.bar is not mangled.

The name of an imported member, e.g., __f in from spam import __f.

The transformation rule is defined as follows:

The class name, with leading underscores removed and a single leading underscore inserted, is inserted in front of the identifier, e.g., the identifier __spam occurring in a class named Foo, _Foo or __Foo is transformed to _Foo__spam.

If the class name consists only of underscores, the transformation is the identity, e.g., the identifier __spam occurring in a class named _ or __ is left as is.

6.2.2. 리터럴 (Literals)

파이썬은 문자열과 바이트열 리터럴과 여러 가지 숫자 리터럴들을 지원합니다:

literal ::=  stringliteral | bytesliteral
             | integer | floatnumber | imagnumber

Evaluation of a literal yields an object of the given type (string, bytes, integer, floating-point number, complex number) with the given value. The value may be approximated in the case of floating-point and imaginary (complex) literals. See section 리터럴 for details.

모든 리터럴은 불변 데이터형에 대응하기 때문에, 객체의 아이덴티티는 값 보다 덜 중요합니다. 같은 값의 리터럴에 대해 반복적으로 값을 구하면 (프로그램 텍스트의 같은 장소에 있거나 다른 장소에 있을 때) 같은 객체를 얻을 수도 있고, 같은 값의 다른 객체를 얻을 수도 있습니다.

6.2.3. 괄호 안에 넣은 형

괄호 안에 넣은 형은, 괄호로 둘러싸인 생략 가능한 표현식 목록입니다:

parenth_form ::=  "(" [starred_expression] ")"

괄호 안에 넣은 표현식 목록은, 무엇이건 그 표현식 목록이 산출하는 것이 됩니다: 목록이 적어도 하나의 쉼표를 포함하면, 튜플이 됩니다; 그렇지 않으면 표현식 목록을 구성한 단일 표현식이 됩니다.

빈 괄호 쌍은 빈 튜플 객체를 만듭니다. 튜플은 불변이기 때문에 리터럴에서와 같은 규칙이 적용됩니다 (즉, 두 개의 빈 튜플은 같은 객체일 수도 있고 그렇지 않을 수도 있습니다).

Note that tuples are not formed by the parentheses, but rather by use of the comma. The exception is the empty tuple, for which parentheses are required — allowing unparenthesized “nothing” in expressions would cause ambiguities and allow common typos to pass uncaught.

6.2.4. 리스트, 집합, 딕셔너리의 디스플레이(display)

리스트, 집합, 딕셔너리를 구성하기 위해, 파이썬은 “디스플레이(displays)”라고 부르는 특별한 문법을 각기 두 가지 스타일로 제공합니다:

컨테이너의 내용을 명시적으로 나열하거나,

일련의 루프와 필터링 지시들을 통해 계산되는데, 컴프리헨션 (comprehension) 이라고 불립니다.

컴프리헨션의 공통 문법 요소들은 이렇습니다:

comprehension ::=  assignment_expression comp_for
comp_for      ::=  ["async"] "for" target_list "in" or_test [comp_iter]
comp_iter     ::=  comp_for | comp_if
comp_if       ::=  "if" or_test [comp_iter]

컴프리헨션은 하나의 표현식과 그 뒤를 따르는 최소한 하나의 for 절과 없거나 여러 개의 for 또는 if 절로 구성됩니다. 이 경우, 새 컨테이너의 요소들은 각 for 또는 if 절이 왼쪽에서 오른쪽으로 중첩된 블록을 이루고, 가장 안쪽에 있는 블록에서 표현식의 값을 구해서 만들어낸 것들입니다.

하지만, 가장 왼쪽의 for 절에 있는 이터러블 표현식을 제외하고는, 컴프리헨션은 묵시적으로 중첩된 스코프에서 실행됩니다. 이렇게 해서 target_list 에서 대입되는 이름이 둘러싸는 스코프로 “누수” 되지 않도록 합니다.

가장 왼쪽의 for 절의 이터러블 표현식은, 둘러싸는 스코프에서 직접 평가된 다음, 묵시적으로 중첩된 스코프로 인자로 전달됩니다. 뒤따르는 for 절과 가장 왼쪽 for 절의 모든 필터 조건은, 가장 왼쪽 이터러블에서 얻은 값에 따라 달라질 수 있으므로 둘러싸는 스코프에서 평가할 수 없습니다. 예를 들면, [x*y for x in range(10) for y in range(x, x+10)].

컴프리헨션이 항상 적절한 형의 컨테이너가 되게 하려고, 묵시적으로 중첩된 스코프에서 yield 와 yield from 표현식은 금지됩니다.

Since Python 3.6, in an async def function, an async for clause may be used to iterate over a asynchronous iterator. A comprehension in an async def function may consist of either a for or async for clause following the leading expression, may contain additional for or async for clauses, and may also use await expressions.

If a comprehension contains async for clauses, or if it contains await expressions or other asynchronous comprehensions anywhere except the iterable expression in the leftmost for clause, it is called an asynchronous comprehension. An asynchronous comprehension may suspend the execution of the coroutine function in which it appears. See also PEP 530 [https://peps.python.org/pep-0530/].

Added in version 3.6: 비동기 컴프리헨션이 도입되었습니다.

버전 3.8에서 변경: yield 와 yield from 은 묵시적으로 중첩된 스코프에서 금지됩니다.

버전 3.11에서 변경: Asynchronous comprehensions are now allowed inside comprehensions in asynchronous functions. Outer comprehensions implicitly become asynchronous.

6.2.5. 리스트 디스플레이

리스트 디스플레이는 대괄호(square brackets)로 둘러싸인 표현식의 나열인데 비어있을 수 있습니다:

list_display ::=  "[" [flexible_expression_list | comprehension] "]"

리스트 디스플레이는 리스트 객체를 만드는데, 그 내용은 표현식의 목록이나 컴프리헨션으로 지정할 수 있습니다. 쉼표로 분리된 표현식의 목록이 제공될 때, 그 요소들은 왼쪽에서 오른쪽으로 값이 구해지고, 그 순서대로 리스트 객체에 삽입됩니다. 컴프리헨션이 제공될 때, 리스트는 컴프리헨션으로 만들어지는 요소들로 구성됩니다.

6.2.6. 집합 디스플레이

집합 디스플레이는 중괄호(curly braces)로 표시되고, 키와 값을 분리하는 콜론(colon)이 없는 것으로 딕셔너리 디스플레이와 구분될 수 있습니다.

set_display ::=  "{" (flexible_expression_list | comprehension) "}"

집합 디스플레이는 새 가변 집합 객체를 만드는데, 그 내용은 표현식의 시퀀스나 컴프리헨션으로 지정됩니다. 쉼표로 분리된 표현식의 목록이 제공될 때, 그 요소들은 왼쪽에서 오른쪽으로 값이 구해지고, 집합 객체에 더해집니다. 컴프리헨션이 제공될 때, 집합은 컴프리헨션으로 만들어지는 요소들로 구성됩니다.

빈 집합은 {} 으로 만들어질 수 없습니다; 이 리터럴은 빈 딕셔너리를 만듭니다.

6.2.7. 딕셔너리 디스플레이

A dictionary display is a possibly empty series of dict items (key/value pairs) enclosed in curly braces:

dict_display       ::=  "{" [dict_item_list | dict_comprehension] "}"
dict_item_list     ::=  dict_item ("," dict_item)* [","]
dict_item          ::=  expression ":" expression | "**" or_expr
dict_comprehension ::=  expression ":" expression comp_for

딕셔너리 디스플레이는 새 딕셔너리 객체를 만듭니다.

If a comma-separated sequence of dict items is given, they are evaluated from left to right to define the entries of the dictionary: each key object is used as a key into the dictionary to store the corresponding value. This means that you can specify the same key multiple times in the dict item list, and the final dictionary’s value for that key will be the last one given.

A double asterisk ** denotes dictionary unpacking. Its operand must be a mapping. Each mapping item is added to the new dictionary. Later values replace values already set by earlier dict items and earlier dictionary unpackings.

Added in version 3.5: PEP 448 [https://peps.python.org/pep-0448/] 에서 처음 제안된 딕셔너리 디스플레이로의 언 패킹.

딕셔너리 컴프리헨션은, 리스트와 집합 컴프리헨션에 대비해서, 일반적인 “for” 와 “if” 절 앞에 콜론으로 분리된 두 개의 표현식을 필요로 합니다. 컴프리헨션이 실행될 때, 만들어지는 키와 값 요소들이 만들어지는 순서대로 딕셔너리에 삽입됩니다.

Restrictions on the types of the key values are listed earlier in section 표준형 계층. (To summarize, the key type should be hashable, which excludes all mutable objects.) Clashes between duplicate keys are not detected; the last value (textually rightmost in the display) stored for a given key value prevails.

버전 3.8에서 변경: 파이썬 3.8 이전에는, 딕셔너리 컴프리헨션에서, 키와 값의 평가 순서가 잘 정의되어 있지 않았습니다. CPython에서, 값이 키보다 먼저 평가되었습니다. 3.8부터는, PEP 572 [https://peps.python.org/pep-0572/]의 제안에 따라 키가 값보다 먼저 평가됩니다.

6.2.8. 제너레이터 표현식 (Generator expressions)

제너레이터 표현식은 괄호로 둘러싸인 간결한 제너레이터 표기법입니다.

generator_expression ::=  "(" expression comp_for ")"

제너레이터 표현식은 새 제너레이터 객체를 만듭니다. 문법은 대괄호나 중괄호 대신 괄호로 둘러싸인다는 점만 제외하면 컴프리헨션과 같습니다.

제너레이터 표현식에 사용되는 변수들은 제너레이터 객체의 __next__() 메서드가 호출될 때 느긋하게(lazily) 값이 구해집니다 (일반 제너레이터와 마찬가지입니다). 그러나 가장 왼쪽의 for 절에 있는 이터러블 표현식은 즉시 값이 구해져서, 그것으로 인해 발생하는 에러는 첫 번째 값이 검색되는 지점이 아니라 제너레이터 표현식이 정의된 지점에서 발생합니다. 후속 for 절과 가장 왼쪽 for 절의 모든 필터 조건은, 가장 왼쪽 이터러블에서 가져온 값에 따라 달라질 수 있으므로 둘러싸는 스코프에서 평가할 수 없습니다. 예를 들어: (x*y for x in range(10) for y in range(x, x+10)).

단지 하나의 인자만 갖는 호출에서는 괄호를 생략할 수 있습니다. 자세한 내용은 호출 섹션을 보세요.

제너레이터 표현식 자체의 기대되는 연산을 방해하지 않기 위해, 묵시적으로 정의된 제너레이터에서 yield 와 yield from 표현식은 금지됩니다.

제너레이터 표현식이 async for 절이나 await 표현식을 포함하면 비동기 제너레이터 표현식 (asynchronous generator expression) 이라고 불립니다. 비동기 제너레이터 표현식은 새 비동기 제너레이터 객체를 돌려주는데 이것은 비동기 이터레이터입니다 (비동기 이터레이터(Asynchronous Iterators) 를 참조하세요).

Added in version 3.6: 비동기식 제너레이터 표현식이 도입되었습니다.

버전 3.7에서 변경: 파이썬 3.7 이전에는, 비동기 제너레이터 표현식이 async def 코루틴에만 나타날 수 있었습니다. 3.7부터는, 모든 함수가 비동기식 제너레이터 표현식을 사용할 수 있습니다.

버전 3.8에서 변경: yield 와 yield from 은 묵시적으로 중첩된 스코프에서 금지됩니다.

6.2.9. 일드 표현식(Yield expressions)

yield_atom       ::=  "(" yield_expression ")"
yield_from       ::=  "yield" "from" expression
yield_expression ::=  "yield" yield_list | yield_from

The yield expression is used when defining a generator function or an asynchronous generator function and thus can only be used in the body of a function definition. Using a yield expression in a function’s body causes that function to be a generator function, and using it in an async def function’s body causes that coroutine function to be an asynchronous generator function. For example:

def gen():  # defines a generator function
    yield 123

async def agen(): # defines an asynchronous generator function
    yield 123

둘러싸는 스코프에 대한 부작용으로 인해, yield 표현식은 컴프리헨션과 제너레이터 표현식을 구현하는 데 사용되는 묵시적으로 정의된 스코프에 사용될 수 없습니다.

버전 3.8에서 변경: 일드 표현식은 컴프리헨션과 제너레이터 표현식을 구현하는 데 사용되는 묵시적으로 정의된 스코프에서 금지됩니다.

제너레이터 함수는 다음에서 설명합니다. 반면에 비동기 제너레이터 함수는 비동기 제너레이터 함수 섹션에서 별도로 설명합니다.

When a generator function is called, it returns an iterator known as a generator. That generator then controls the execution of the generator function. The execution starts when one of the generator’s methods is called. At that time, the execution proceeds to the first yield expression, where it is suspended again, returning the value of yield_list to the generator’s caller, or None if yield_list is omitted. By suspended, we mean that all local state is retained, including the current bindings of local variables, the instruction pointer, the internal evaluation stack, and the state of any exception handling. When the execution is resumed by calling one of the generator’s methods, the function can proceed exactly as if the yield expression were just another external call. The value of the yield expression after resuming depends on the method which resumed the execution. If __next__() is used (typically via either a for or the next() builtin) then the result is None. Otherwise, if send() is used, then the result will be the value passed in to that method.

이 모든 것들은 제너레이터 함수를 코루틴과 아주 비슷하게 만듭니다; 여러 번 결과를 만들고, 하나 이상의 진입 지점을 갖고 있으며, 실행이 일시 중지될 수 있습니다. 유일한 차이점은 제너레이터 함수는 yield 한 후에 실행이 어디에서 계속되어야 하는지를 제어할 수 없다는 점입니다; 제어는 항상 제너레이터의 호출자로 전달됩니다.

일드 표현식은 try 구조물의 어디에서건 허락됩니다. 제너레이터가 (참조 횟수가 0이 되거나 가비지 수거됨으로써) 파이널라이즈(finalize)되기 전에 재개되지 않으면, 제너레이터-이터레이터의 close() 메서드가 호출되어, 대기 중인 finally 절이 실행되도록 허락합니다.

yield from <expr> 이 사용될 때, 제공된 표현식은 어터러블이어야 합니다. 그 이터러블을 이터레이트 해서 생성되는 값들은 현재 제너레이터 메서드의 호출자에게 바로 전달됩니다. send() 로 전달된 모든 값과 throw() 로 전달된 모든 예외는 밑에 있는(underlying) 이터레이터가 해당 메서드를 갖고 있다면 그곳으로 전달됩니다. 그렇지 않다면, send() 는 AttributeError 나 TypeError 를 일으키지만, throw() 는 전달된 예외를 즉시 일으킨다.

밑에 있는 이러레이터가 완료될 때, 발생하는 StopIteration 인스턴스의 value 어트리뷰트는 일드 표현식의 값이 됩니다. StopIteration 를 일으킬 때 명시적으로 설정되거나, 서브 이터레이터가 제너레이터일 경우는 자동으로 이루어집니다 (서브 제너레이터가 값을 돌려(return)줌으로써).

버전 3.3에서 변경: 서브 이터레이터로 제어 흐름을 위임하는 yield from <expr> 를 추가했습니다.

일드 표현식이 대입문의 우변에 홀로 나온다면 괄호를 생략할 수 있습니다.

더 보기

PEP 255 [https://peps.python.org/pep-0255/] - 간단한 제너레이터

파이썬에 제너레이터와 yield 문을 추가하는 제안.

PEP 342 [https://peps.python.org/pep-0342/] - 개선된 제너레이터를 통한 코루틴

제너레이터의 API와 문법을 개선해서, 간단한 코루틴으로 사용할 수 있도록 만드는 제안.

PEP 380 [https://peps.python.org/pep-0380/] - 서브 제너레이터로 위임하는 문법

The proposal to introduce the yield_from syntax, making delegation to subgenerators easy.

PEP 525 [https://peps.python.org/pep-0525/] - 비동기 제너레이터

코루틴 함수에 제너레이터 기능을 추가하여 PEP 492 [https://peps.python.org/pep-0492/]을 확장한 제안.

6.2.9.1. 제너레이터-이터레이터 메서드

이 서브섹션은 제너레이터 이터레이터의 메서드들을 설명합니다. 제너레이터 함수의 실행을 제어하는데 사용될 수 있습니다.

제너레이터가 이미 실행 중일 때 아래에 나오는 메서드들을 호출하면 ValueError 예외를 일으키는 것에 주의해야 합니다.

generator.__next__()

Starts the execution of a generator function or resumes it at the last executed yield expression. When a generator function is resumed with a __next__() method, the current yield expression always evaluates to None. The execution then continues to the next yield expression, where the generator is suspended again, and the value of the yield_list is returned to __next__()’s caller. If the generator exits without yielding another value, a StopIteration exception is raised.

이 메서드는 보통 묵시적으로 호출됩니다, 예를 들어, for 루프나 내장 next() 함수에 의해.

generator.send(value)

실행을 재개하고 제너레이터 함수로 값을 “보냅니다(send)”. value 인자는 현재 일드 표현식의 값이 됩니다. send() 메서드는 제너레이터가 yield 하는 다음 값을 돌려주거나, 제너레이터가 다른 값을 yield 하지 않고 종료하면 StopIteration 을 일으킵니다. send() 가 제너레이터를 시작시키도록 호출될 때, 값을 받을 일드 표현식이 없으므로, 인자로는 반드시 None 을 전달해야 합니다.

generator.throw(value)

generator.throw(type[, value[, traceback]])

Raises an exception at the point where the generator was paused, and returns the next value yielded by the generator function. If the generator exits without yielding another value, a StopIteration exception is raised. If the generator function does not catch the passed-in exception, or raises a different exception, then that exception propagates to the caller.

In typical use, this is called with a single exception instance similar to the way the raise keyword is used.

For backwards compatibility, however, the second signature is supported, following a convention from older versions of Python. The type argument should be an exception class, and value should be an exception instance. If the value is not provided, the type constructor is called to get an instance. If traceback is provided, it is set on the exception, otherwise any existing __traceback__ attribute stored in value may be cleared.

버전 3.12에서 변경: The second signature (type[, value[, traceback]]) is deprecated and may be removed in a future version of Python.

generator.close()

Raises a GeneratorExit at the point where the generator function was paused. If the generator function catches the exception and returns a value, this value is returned from close(). If the generator function is already closed, or raises GeneratorExit (by not catching the exception), close() returns None. If the generator yields a value, a RuntimeError is raised. If the generator raises any other exception, it is propagated to the caller. If the generator has already exited due to an exception or normal exit, close() returns None and has no other effect.

버전 3.13에서 변경: If a generator returns a value upon being closed, the value is returned by close().

6.2.9.2. 사용 예

여기에 제너레이터와 제너레이터 함수의 동작을 시연하는 간단한 예가 있습니다:

>>> def echo(value=None):
...     print("Execution starts when 'next()' is called for the first time.")
...     try:
...         while True:
...             try:
...                 value = (yield value)
...             except Exception as e:
...                 value = e
...     finally:
...         print("Don't forget to clean up when 'close()' is called.")
...
>>> generator = echo(1)
>>> print(next(generator))
Execution starts when 'next()' is called for the first time.
1
>>> print(next(generator))
None
>>> print(generator.send(2))
2
>>> generator.throw(TypeError, "spam")
TypeError('spam',)
>>> generator.close()
Don't forget to clean up when 'close()' is called.

yield from 을 사용하는 예는, “What’s New in Python.” 에 있는 PEP 380: Syntax for Delegating to a Subgenerator 을 보세요.

6.2.9.3. 비동기 제너레이터 함수

async def 를 사용한 함수나 메서드에서 일드 표현식의 존재는 그 함수를 비동기 제너레이터 함수로 정의합니다.

비동기 제너레이터 함수가 호출되면, 비동기 제너레이터 객체로 알려진 비동기 이터레이터를 돌려줍니다. 그런 다음 그 객체는 제너레이터 함수의 실행을 제어합니다. 비동기 제너레이터 객체는 보통 코루틴 함수의 async for 문에서 사용되는데, 제너레이터 객체가 for 문에서 사용되는 방식과 유사합니다.

Calling one of the asynchronous generator’s methods returns an awaitable object, and the execution starts when this object is awaited on. At that time, the execution proceeds to the first yield expression, where it is suspended again, returning the value of yield_list to the awaiting coroutine. As with a generator, suspension means that all local state is retained, including the current bindings of local variables, the instruction pointer, the internal evaluation stack, and the state of any exception handling. When the execution is resumed by awaiting on the next object returned by the asynchronous generator’s methods, the function can proceed exactly as if the yield expression were just another external call. The value of the yield expression after resuming depends on the method which resumed the execution. If __anext__() is used then the result is None. Otherwise, if asend() is used, then the result will be the value passed in to that method.

If an asynchronous generator happens to exit early by break, the caller task being cancelled, or other exceptions, the generator’s async cleanup code will run and possibly raise exceptions or access context variables in an unexpected context–perhaps after the lifetime of tasks it depends, or during the event loop shutdown when the async-generator garbage collection hook is called. To prevent this, the caller must explicitly close the async generator by calling aclose() method to finalize the generator and ultimately detach it from the event loop.

비동기 제너레이터 함수에서, 일드 표현식은 try 구조물의 어디에서건 허락됩니다. 하지만, 비동기 제너레이터가 (참조 횟수가 0이 되거나 가비지 수거됨으로써) 파이널라이즈(finalize)되기 전에 재개되지 않으면, try 구조물 내의 일드 표현식은 대기 중인 finally 절을 실행하는 데 실패할 수 있습니다. 이 경우에, 비동기 제너레이터-이터레이터의 aclose() 를 호출하고, 그 결과로 오는 코루틴 객체를 실행해서, 대기 중인 finally 절이 실행되도록 하는 책임은, 비동기 제너레이터를 실행하는 이벤트 루프(event loop)나 스케줄러(scheduler)에게 있습니다.

To take care of finalization upon event loop termination, an event loop should define a finalizer function which takes an asynchronous generator-iterator and presumably calls aclose() and executes the coroutine. This finalizer may be registered by calling sys.set_asyncgen_hooks(). When first iterated over, an asynchronous generator-iterator will store the registered finalizer to be called upon finalization. For a reference example of a finalizer method see the implementation of asyncio.Loop.shutdown_asyncgens in Lib/asyncio/base_events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/base_events.py].

표현식 yield from <expr> 를 비동기 제너레이터 함수에서 사용하는 것은 문법 에러다.

6.2.9.4. 비동기 제너레이터-이터레이터 메서드

이 서브섹션은 비동기 제너레이터 이터레이터의 메서드를 설명하는데, 제너레이터 함수의 실행을 제어하는 데 사용됩니다.

coroutine agen.__anext__()

Returns an awaitable which when run starts to execute the asynchronous generator or resumes it at the last executed yield expression. When an asynchronous generator function is resumed with an __anext__() method, the current yield expression always evaluates to None in the returned awaitable, which when run will continue to the next yield expression. The value of the yield_list of the yield expression is the value of the StopIteration exception raised by the completing coroutine. If the asynchronous generator exits without yielding another value, the awaitable instead raises a StopAsyncIteration exception, signalling that the asynchronous iteration has completed.

이 메서드는 보통 async for 루프에 의해 묵시적으로 호출됩니다.

coroutine agen.asend(value)

Returns an awaitable which when run resumes the execution of the asynchronous generator. As with the send() method for a generator, this “sends” a value into the asynchronous generator function, and the value argument becomes the result of the current yield expression. The awaitable returned by the asend() method will return the next value yielded by the generator as the value of the raised StopIteration, or raises StopAsyncIteration if the asynchronous generator exits without yielding another value. When asend() is called to start the asynchronous generator, it must be called with None as the argument, because there is no yield expression that could receive the value.

coroutine agen.athrow(value)

coroutine agen.athrow(type[, value[, traceback]])

어웨이터블을 돌려주는데, 비동기 제너레이터가 일시 중지한 지점에 type 형의 예외를 일으키고, 제너레이터 함수가 yield 한 다음 값을 발생하는 StopIteration 예외의 값으로 돌려줍니다. 비동기 제너레이터가 다른 값을 yield 하지 않고 종료하면, 어웨이터블에 의해 StopAsyncIteration 예외가 일어납니다. 제너레이터 함수가 전달된 예외를 잡지 않거나, 다른 예외를 일으키면, 어웨이터블을 실행할 때 그 예외가 어웨이터블의 호출자에게 퍼집니다.

버전 3.12에서 변경: The second signature (type[, value[, traceback]]) is deprecated and may be removed in a future version of Python.

coroutine agen.aclose()

어웨이터블을 돌려주는데, 실행하면, 비동기 제너레이터 함수가 일시 정지한 지점으로 GeneratorExit 를 던집니다. 만약 그 이후에 비동기 제너레이터 함수가 우아하게 (gracefully) 종료하거나, 이미 닫혔거나, (그 예외를 잡지 않음으로써) GeneratorExit 를 일으키면, 돌려준 어웨이터블은 StopIteration 예외를 일으킵니다. 이어지는 비동기 제너레이터 호출이 돌려주는 추가의 어웨이터블들은 StopAsyncIteration 예외를 일으킵니다. 만약 비동기 제너레이터가 값을 yield 하면 어웨이터블에 의해 RuntimeError 가 발생합니다. 만약 비동기 제너레이터가 그 밖의 다른 예외를 일으키면, 어웨이터블의 호출자로 퍼집니다. 만약 비동기 제너레이터가 예외나 정상 종료로 이미 종료했으면, 더 이어지는 aclose() 호출은 아무것도 하지 않는 어웨이터블을 돌려줍니다.

6.3. 프라이머리

프라이머리는 언어에서 가장 강하게 결합하는 연산들을 나타냅니다. 문법은 이렇습니다:

primary ::=  atom | attributeref | subscription | slicing | call

6.3.1. 어트리뷰트 참조

어트리뷰트 참조는 마침표(period)와 이름이 뒤에 붙은 프라이머리다:

attributeref ::=  primary "." identifier

The primary must evaluate to an object of a type that supports attribute references, which most objects do. This object is then asked to produce the attribute whose name is the identifier. The type and value produced is determined by the object. Multiple evaluations of the same attribute reference may yield different objects.

This production can be customized by overriding the __getattribute__() method or the __getattr__() method. The __getattribute__() method is called first and either returns a value or raises AttributeError if the attribute is not available.

If an AttributeError is raised and the object has a __getattr__() method, that method is called as a fallback.

6.3.2. 서브스크립션(Subscriptions)

The subscription of an instance of a container class will generally select an element from the container. The subscription of a generic class will generally return a GenericAlias object.

subscription ::=  primary "[" flexible_expression_list "]"

When an object is subscripted, the interpreter will evaluate the primary and the expression list.

The primary must evaluate to an object that supports subscription. An object may support subscription through defining one or both of __getitem__() and __class_getitem__(). When the primary is subscripted, the evaluated result of the expression list will be passed to one of these methods. For more details on when __class_getitem__ is called instead of __getitem__, see __class_getitem__ versus __getitem__.

If the expression list contains at least one comma, or if any of the expressions are starred, the expression list will evaluate to a tuple containing the items of the expression list. Otherwise, the expression list will evaluate to the value of the list’s sole member.

버전 3.11에서 변경: Expressions in an expression list may be starred. See PEP 646 [https://peps.python.org/pep-0646/].

For built-in objects, there are two types of objects that support subscription via __getitem__():

Mappings. If the primary is a mapping, the expression list must evaluate to an object whose value is one of the keys of the mapping, and the subscription selects the value in the mapping that corresponds to that key. An example of a builtin mapping class is the dict class.

Sequences. If the primary is a sequence, the expression list must evaluate to an int or a slice (as discussed in the following section). Examples of builtin sequence classes include the str, list and tuple classes.

The formal syntax makes no special provision for negative indices in sequences. However, built-in sequences all provide a __getitem__() method that interprets negative indices by adding the length of the sequence to the index so that, for example, x[-1] selects the last item of x. The resulting value must be a nonnegative integer less than the number of items in the sequence, and the subscription selects the item whose index is that value (counting from zero). Since the support for negative indices and slicing occurs in the object’s __getitem__() method, subclasses overriding this method will need to explicitly add that support.

A string is a special kind of sequence whose items are characters. A character is not a separate data type but a string of exactly one character.

6.3.3. 슬라이싱(Slicings)

슬라이싱은 시퀀스 객체 (예를 들어, 문자열 튜플 리스트)에서 어떤 범위의 항목들을 선택합니다. 슬라이싱은 표현식이나 대입의 타깃이나 del 문에 사용될 수 있습니다. 슬라이싱의 문법은 이렇습니다:

slicing      ::=  primary "[" slice_list "]"
slice_list   ::=  slice_item ("," slice_item)* [","]
slice_item   ::=  expression | proper_slice
proper_slice ::=  [lower_bound] ":" [upper_bound] [ ":" [stride] ]
lower_bound  ::=  expression
upper_bound  ::=  expression
stride       ::=  expression

이 형식 문법에는 모호함이 있습니다: 표현식 목록처럼 보이는 것들은 모두 슬라이스 목록으로 보이기도 해서, 모든 서브스크립션이 슬라이싱으로 해석될 수도 있습니다. 문법을 더 복잡하게 만드는 대신, 이 경우에 서브스크립션으로 해석하는 것이 슬라이싱으로 해석하는 것에 우선한다고 정의하는 것으로 애매함을 제거합니다 (이 경우는 슬라이스 목록이 고유한 슬라이스(proper slice) 를 하나도 포함하지 않을 때입니다).

The semantics for a slicing are as follows. The primary is indexed (using the same __getitem__() method as normal subscription) with a key that is constructed from the slice list, as follows. If the slice list contains at least one comma, the key is a tuple containing the conversion of the slice items; otherwise, the conversion of the lone slice item is the key. The conversion of a slice item that is an expression is that expression. The conversion of a proper slice is a slice object (see section 표준형 계층) whose start, stop and step attributes are the values of the expressions given as lower bound, upper bound and stride, respectively, substituting None for missing expressions.

6.3.4. 호출

호출은 콜러블 객체 (예를 들어, 함수) 를 빌 수도 있는 인자 들의 목록으로 호출합니다.

call                 ::=  primary "(" [argument_list [","] | comprehension] ")"
argument_list        ::=  positional_arguments ["," starred_and_keywords]
                            ["," keywords_arguments]
                          | starred_and_keywords ["," keywords_arguments]
                          | keywords_arguments
positional_arguments ::=  positional_item ("," positional_item)*
positional_item      ::=  assignment_expression | "*" expression
starred_and_keywords ::=  ("*" expression | keyword_item)
                          ("," "*" expression | "," keyword_item)*
keywords_arguments   ::=  (keyword_item | "**" expression)
                          ("," keyword_item | "," "**" expression)*
keyword_item         ::=  identifier "=" expression

생략할 수 있는 마지막 쉼표가 위치나 키워드 인자 뒤에 나타날 수 있지만, 의미를 바꾸지 않습니다.

The primary must evaluate to a callable object (user-defined functions, built-in functions, methods of built-in objects, class objects, methods of class instances, and all objects having a __call__() method are callable). All argument expressions are evaluated before the call is attempted. Please refer to section 함수 정의 for the syntax of formal parameter lists.

If keyword arguments are present, they are first converted to positional arguments, as follows. First, a list of unfilled slots is created for the formal parameters. If there are N positional arguments, they are placed in the first N slots. Next, for each keyword argument, the identifier is used to determine the corresponding slot (if the identifier is the same as the first formal parameter name, the first slot is used, and so on). If the slot is already filled, a TypeError exception is raised. Otherwise, the argument is placed in the slot, filling it (even if the expression is None, it fills the slot). When all arguments have been processed, the slots that are still unfilled are filled with the corresponding default value from the function definition. (Default values are calculated, once, when the function is defined; thus, a mutable object such as a list or dictionary used as default value will be shared by all calls that don’t specify an argument value for the corresponding slot; this should usually be avoided.) If there are any unfilled slots for which no default value is specified, a TypeError exception is raised. Otherwise, the list of filled slots is used as the argument list for the call.

CPython 구현 상세: 구현은 위치 매개변수가 이름을 갖지 않아서, 설사 문서화의 목적으로 이름이 붙여졌다 하더라도, 키워드로 공급될 수 없는 내장 함수들을 제공할 수 있습니다. CPython 에서, 인자들을 파싱하기 위해 PyArg_ParseTuple() 를 사용하는 C로 구현된 함수들이 이 경우입니다.

형식 매개변수 슬롯들보다 많은 위치 인자들이 있으면, *identifier 문법을 사용하는 형식 매개변수가 있지 않은 한, TypeError 예외를 일으킵니다; 이 경우, 그 형식 매개변수는 남는 위치 인자들을 포함하는 튜플을 전달받습니다 (또는 남는 위치 인자들이 없으면 빈 튜플).

키워드 인자가 형식 매개변수 이름에 대응하지 않으면, **identifier 문법을 사용하는 형식 매개변수가 있지 않은 한, TypeError 예외를 일으킵니다; 이 경우, 그 형식 매개변수는 남는 키워드 인자들을 포함하는 딕셔너리나, 남는 위치기반 인자들이 없으면 빈 (새) 딕셔너리를 전달받습니다.

문법 *expression 이 함수 호출에 등장하면, expression 의 값은 이터러블 이 되어야 합니다. 이 이터러블의 요소들은, 그것들이 추가의 위치 인자들인 것처럼 취급됩니다. 호출 f(x1, x2, *y, x3, x4) 의 경우, y 의 값을 구할 때 시퀀스 y1, …, yM 이 나온다면, 이것은 M+4개의 위치 인자들 x1, x2, y1, …, yM, x3, x4 로 호출하는 것과 동등합니다.

이로 인한 결과는 설사 *expression 문법이 명시적인 키워드 인자 뒤에 나올 수는 있어도, 키워드 인자 (그리고 모든 **expression 인자들 – 아래를 보라) 전에 처리된다는 것입니다. 그래서:

>>> def f(a, b):
...     print(a, b)
...
>>> f(b=1, *(2,))
2 1
>>> f(a=1, *(2,))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: f() got multiple values for keyword argument 'a'
>>> f(1, *(2,))
1 2

It is unusual for both keyword arguments and the *expression syntax to be used in the same call, so in practice this confusion does not often arise.

If the syntax **expression appears in the function call, expression must evaluate to a mapping, the contents of which are treated as additional keyword arguments. If a parameter matching a key has already been given a value (by an explicit keyword argument, or from another unpacking), a TypeError exception is raised.

When **expression is used, each key in this mapping must be a string. Each value from the mapping is assigned to the first formal parameter eligible for keyword assignment whose name is equal to the key. A key need not be a Python identifier (e.g. "max-temp °F" is acceptable, although it will not match any formal parameter that could be declared). If there is no match to a formal parameter the key-value pair is collected by the ** parameter, if there is one, or if there is not, a TypeError exception is raised.

문법 *identifier 이나 **identifier 를 사용하는 형식 매개변수들은 위치 인자 슬롯이나 키워드 인자 아름들로 사용될 수 없습니다.

버전 3.5에서 변경: 함수 호출은 임의의 개수의 * and ** 언 패킹을 받아들이고, 위치 인자들이 이터러블 언 패킹 (*) 뒤에 올 수 있고, 키워드 인자가 딕셔너리 언 패킹 (**) 뒤에 올 수 있습니다. 최초로 PEP 448 [https://peps.python.org/pep-0448/] 에서 제안되었습니다.

호출은 예외를 일으키지 않는 한, 항상 어떤 값을 돌려줍니다, None 일 수 있습니다. 이 값이 어떻게 계산되는지는 콜러블 객체의 형에 달려있습니다.

만약 그것이—

사용자 정의 함수면:

The code block for the function is executed, passing it the argument list. The first thing the code block will do is bind the formal parameters to the arguments; this is described in section 함수 정의. When the code block executes a return statement, this specifies the return value of the function call. If execution reaches the end of the code block without executing a return statement, the return value is None.

내장 함수나 메서드면:

결과는 인터프리터에 달려있습니다; 내장 함수와 메서드들에 대한 설명은 내장 함수 를 보세요.

클래스 객체면:

그 클래스의 새 인스턴스가 반환됩니다.

클래스 인스턴스 메서드면:

대응하는 사용자 정의 함수가 호출되는데, 그 인스턴스가 첫 번째 인자가 되는 하나만큼 더 긴 인자 목록이 전달됩니다.

클래스 인스턴스면:

The class must define a __call__() method; the effect is then the same as if that method was called.

6.4. 어웨이트 표현식

어웨이터블 에서 코루틴 의 실행을 일시 중지합니다. 오직 코루틴 함수 에서만 사용할 수 있습니다.

await_expr ::=  "await" primary

Added in version 3.5.

6.5. 거듭제곱 연산자

거듭제곱 연산자는 그것의 왼쪽에 붙는 일 항 연산자보다 더 강하게 결합합니다; 그것의 오른쪽에 붙는 일 항 연산자보다는 약하게 결합합니다. 문법은 이렇습니다:

power ::=  (await_expr | primary) ["**" u_expr]

그래서, 괄호가 없는 거듭제곱과 일 항 연산자의 시퀀스에서, 연산자는 오른쪽에서 왼쪽으로 값이 구해집니다 (이것이 피연산자의 값을 구하는 순서를 제약하는 것은 아닙니다): -1**2 은 -1 이 됩니다.

거듭제곱 연산자는 내장 pow() 함수가 두 개의 인자로 호출될 때와 같은 의미가 있습니다: 왼쪽 인자를 오른쪽 인자만큼 거듭제곱한 값을 줍니다. 숫자 인자는 먼저 공통 형으로 변환되고, 결과는 그 형입니다.

int 피연산자의 경우, 두 번째 인자가 음수가 아닌 이상 결과는 피연산자들과 같은 형을 갖습니다; 두 번째 인자가 음수면, 모든 인자는 float로 변환되고, float 결과가 전달됩니다. 예를 들어, 10**2 는 100 를 돌려주지만, 10**-2 는 0.01 를 돌려줍니다.

0.0 를 음수로 거듭제곱하면 ZeroDivisionError 를 일으킵니다. 음수를 분수로 거듭제곱하면 복소수(complex)가 나옵니다. (예전 버전에서는 ValueError 를 일으켰습니다.)

This operation can be customized using the special __pow__() and __rpow__() methods.

6.6. 일 항 산술과 비트 연산

모든 일 항 산술과 비트 연산자는 같은 우선순위를 갖습니다.

u_expr ::=  power | "-" u_expr | "+" u_expr | "~" u_expr

The unary - (minus) operator yields the negation of its numeric argument; the operation can be overridden with the __neg__() special method.

The unary + (plus) operator yields its numeric argument unchanged; the operation can be overridden with the __pos__() special method.

The unary ~ (invert) operator yields the bitwise inversion of its integer argument. The bitwise inversion of x is defined as -(x+1). It only applies to integral numbers or to custom objects that override the __invert__() special method.

세 가지 경우 모두, 인자가 올바른 형을 갖지 않는다면, TypeError 예외가 발생합니다.

6.7. 이항 산술 연산

이항 산술 연산자는 관습적인 우선순위를 갖습니다. 이 연산자 중 일부는 일부 비 숫자 형에도 적용됨에 주의해야 합니다. 거듭제곱 연산자와는 별개로, 오직 두 가지 수준만 있는데, 하나는 곱셈형 연산자들이고, 하나는 덧셈형 연산자들입니다.

m_expr ::=  u_expr | m_expr "*" u_expr | m_expr "@" m_expr |
            m_expr "//" u_expr | m_expr "/" u_expr |
            m_expr "%" u_expr
a_expr ::=  m_expr | a_expr "+" m_expr | a_expr "-" m_expr

The * (multiplication) operator yields the product of its arguments. The arguments must either both be numbers, or one argument must be an integer and the other must be a sequence. In the former case, the numbers are converted to a common real type and then multiplied together. In the latter case, sequence repetition is performed; a negative repetition factor yields an empty sequence.

This operation can be customized using the special __mul__() and __rmul__() methods.

버전 3.14에서 변경: If only one operand is a complex number, the other operand is converted to a floating-point number.

@ (at) 연산자는 행렬 곱셈에 사용하려는 것입니다. 파이썬의 내장형들 어느 것도 이 연산자를 구현하지 않습니다.

This operation can be customized using the special __matmul__() and __rmatmul__() methods.

Added in version 3.5.

/ (나눗셈)과 // (정수 나눗셈, floor division) 연산자들은 그 인자들의 몫(quotient)을 줍니다. 숫자 인자들은 먼저 공통형으로 변환됩니다. 정수들의 나눗셈은 실수를 만드는 반면, 정수들의 정수 나눗셈은 정숫값을 줍니다; 그 결과는 수학적인 나눗셈의 결과에 ‘floor’ 함수를 적용한 것입니다. 0으로 나누는 것은 ZeroDivisionError 예외를 일으킵니다.

The division operation can be customized using the special __truediv__() and __rtruediv__() methods. The floor division operation can be customized using the special __floordiv__() and __rfloordiv__() methods.

The % (modulo) operator yields the remainder from the division of the first argument by the second. The numeric arguments are first converted to a common type. A zero right argument raises the ZeroDivisionError exception. The arguments may be floating-point numbers, e.g., 3.14%0.7 equals 0.34 (since 3.14 equals 4*0.7 + 0.34.) The modulo operator always yields a result with the same sign as its second operand (or zero); the absolute value of the result is strictly smaller than the absolute value of the second operand [1].

정수 나눗셈과 모듈로 연산자는 다음과 같은 항등식으로 연결되어 있습니다: x == (x//y)*y + (x%y). 정수 나눗셈과 모듈로는 내장 함수 divmod() 와도 연결되어 있습니다: divmod(x, y) == (x//y, x%y). [2].

숫자들에 대해 모듈로 연산을 수행하는 것에 더해, % 연산자는 예전 스타일의 문자열 포매팅 (인터폴레이션이라고도 알려져 있습니다)을 수행하기 위해 문자열 객체에 의해 다시 정의됩니다. 문자열 포매팅의 문법은 파이썬 라이브러리 레퍼런스의 섹션 printf 스타일 문자열 포매팅 에서 설명합니다.

The modulo operation can be customized using the special __mod__() and __rmod__() methods.

The floor division operator, the modulo operator, and the divmod() function are not defined for complex numbers. Instead, convert to a floating-point number using the abs() function if appropriate.

The + (addition) operator yields the sum of its arguments. The arguments must either both be numbers or both be sequences of the same type. In the former case, the numbers are converted to a common real type and then added together. In the latter case, the sequences are concatenated.

This operation can be customized using the special __add__() and __radd__() methods.

버전 3.14에서 변경: If only one operand is a complex number, the other operand is converted to a floating-point number.

The - (subtraction) operator yields the difference of its arguments. The numeric arguments are first converted to a common real type.

This operation can be customized using the special __sub__() and __rsub__() methods.

버전 3.14에서 변경: If only one operand is a complex number, the other operand is converted to a floating-point number.

6.8. 시프트 연산

시프트 연산은 산술 연산보다 낮은 우선순위를 갖습니다.

shift_expr ::=  a_expr | shift_expr ("<<" | ">>") a_expr

이 연산들은 정수들을 인자로 받아들입니다. 첫 번째 인자를 두 번째 인자로 주어진 비트 수만큼 왼쪽이나 오른쪽으로 밉니다(shift).

The left shift operation can be customized using the special __lshift__() and __rlshift__() methods. The right shift operation can be customized using the special __rshift__() and __rrshift__() methods.

오른쪽으로 n 비트 시프트 하는 것은 pow(2,n) 로 정수 나눗셈하는 것으로 정의됩니다. 왼쪽으로 n 비트 시프트 하는 것은 pow(2,n) 를 곱하는 것으로 정의됩니다.

6.9. 이항 비트 연산

세 개의 비트 연산은 각기 다른 우선순위를 갖습니다:

and_expr ::=  shift_expr | and_expr "&" shift_expr
xor_expr ::=  and_expr | xor_expr "^" and_expr
or_expr  ::=  xor_expr | or_expr "|" xor_expr

The & operator yields the bitwise AND of its arguments, which must be integers or one of them must be a custom object overriding __and__() or __rand__() special methods.

The ^ operator yields the bitwise XOR (exclusive OR) of its arguments, which must be integers or one of them must be a custom object overriding __xor__() or __rxor__() special methods.

The | operator yields the bitwise (inclusive) OR of its arguments, which must be integers or one of them must be a custom object overriding __or__() or __ror__() special methods.

6.10. 비교

C와는 달리, 파이썬에서 모든 비교 연산은 같은 우선순위를 갖는데, 산술, 시프팅, 비트 연산들보다 낮습니다. 또한, C와는 달리, a < b < c 와 같은 표현식이 수학에서와 같은 방식으로 해석됩니다.

comparison    ::=  or_expr (comp_operator or_expr)*
comp_operator ::=  "<" | ">" | "==" | ">=" | "<=" | "!="
                   | "is" ["not"] | ["not"] "in"

Comparisons yield boolean values: True or False. Custom rich comparison methods may return non-boolean values. In this case Python will call bool() on such value in boolean contexts.

비교는 자유롭게 연결될 수 있습니다, 예를 들어, x < y <= z 는 x < y and y <= z 와 동등한데, 차이점은 y 의 값을 오직 한 번만 구한다는 것입니다 (하지만 두 경우 모두 x < y 가 거짓이면 z 의 값은 구하지 않습니다).

형식적으로, a, b, c, …, y, z 가 표현식이고, op1, op2, …, opN 가 비교 연산자면, a op1 b op2 c ... y opN z 는 각 표현식의 값을 최대 한 번만 구한다는 점을 제외하고는 a op1 b and b op2 c and ... y opN z 와 동등합니다.

a op1 b op2 c 가 a 와 c 간의 어떤 종류의 비교도 암시하지 않기 때문에, 예를 들어, x < y > z 이 완벽하게 (아마 이쁘지는 않더라도) 올바르다는 것에 주의해야 합니다.

6.10.1. 값 비교

연산자 <, >, ==, >=, <=, != 는 두 객체의 값을 비교합니다. 객체들이 같은 형일 필요는 없습니다.

객체, 값, 형 장은 객체들이 (형과 아이덴티티에 더해) 값을 갖는다고 말하고 있습니다. 파이썬에서 객체의 값은 좀 추상적인 개념입니다: 예를 들어, 객체의 값에 대한 규범적인(canonical) 액세스 방법은 없습니다. 또한, 객체의 값이 특별한 방식(예를 들어, 모든 데이터 어트리뷰트로 구성되는 것)으로 구성되어야 한다는 요구 사항도 없습니다. 비교 연산자는 객체의 값이 무엇인지에 대한 특정한 종류의 개념을 구현합니다. 객체의 값을 비교를 통해 간접적으로 정의한다고 생각해도 좋습니다.

Because all types are (direct or indirect) subtypes of object, they inherit the default comparison behavior from object. Types can customize their comparison behavior by implementing rich comparison methods like __lt__(), described in 기본적인 커스터마이제이션.

동등 비교 (== 와 !=) 의 기본 동작은 객체의 아이덴티티에 기반을 둡니다. 그래서, 같은 아이덴티티를 갖는 인스턴스 간의 동등 비교는 같음을 주고, 다른 아이덴티티를 갖는 인스턴스 간의 동등 비교는 다름을 줍니다. 이 기본 동작의 동기는 모든 객체가 반사적(reflexive) (즉, x is y 는 x == y 를 암시합니다) 이도록 만들고자 하는 욕구입니다.

기본 대소 비교(order comparison) (<, >, <=, >=) 는 제공되지 않습니다; 시도하면 TypeError 를 일으킵니다. 이 기본 동작의 동기는 동등함과 유사한 항등 관계가 없다는 것입니다.

다른 아이덴티티를 갖는 인스턴스들이 항상 서로 다르다는, 기본 동등 비교의 동작은, 객체의 값과 값 기반의 동등함에 대한 나름의 정의를 가진 형들이 필요로 하는 것과는 크게 다를 수 있습니다. 그런 형들은 자신의 비교 동작을 커스터마이즈 할 필요가 있고, 사실 많은 내장형이 그렇게 하고 있습니다.

다음 목록은 가장 중요한 내장형들의 비교 동작을 기술합니다.

내장 숫자 형 ((숫자 형 — int, float, complex)) 과 표준 라이브러리 형 fractions.Fraction 과 decimal.Decimal 에 속하는 숫자들은, 복소수가 대소 비교를 지원하지 않는다는 제약 사항만 빼고는, 같거나 다른 형들 간의 비교가 가능합니다. 관련된 형들의 한계 안에서, 정밀도의 손실 없이 수학적으로 (알고리즘 적으로) 올바르게 비교합니다.

NaN(not-a-number) 값들 float('NaN') 과 decimal.Decimal('NaN')은 특별합니다. 모든 숫자와 NaN 간의 비교는 거짓입니다. 반 직관적으로 내포하고 있는 것은, NaN 이 자신과 같지 않다는 것입니다. 예를 들어, x = float('NaN'), 3 < x, x < 3 및 x == x는 모두 거짓이지만, x != x는 참입니다. 이 동작은 IEEE 754를 준수합니다.

None and NotImplemented are singletons. PEP 8 [https://peps.python.org/pep-0008/] advises that comparisons for singletons should always be done with is or is not, never the equality operators.

바이너리 시퀀스들 (bytes 나 bytearray 의 인스턴스들)은 형을 건너 상호 비교될 수 있습니다. 이것들은 요소들의 숫자 값을 사용해서 사전식으로(lexicographically) 비교합니다.

문자열들 (str 의 인스턴스들) 은 문자들의 유니코드 코드 포인트(Unicode code points) (내장 함수 ord() 의 결과)를 사용해서 사전식으로 비교합니다. [3]

문자열과 바이너리 시퀀스는 직접 비교할 수 없습니다.

시퀀스들 (tuple, list, range 의 인스턴스들)은 같은 형끼리 비교될 수 있는데, range는 대소 비교를 지원하지 않습니다. 서로 다른 형들 간의 동등 비교는 다름을 주고, 서로 다른 형들 간의 대소 비교는 TypeError 를 일으킵니다.

시퀀스는 대응하는 요소 간의 비교를 사용해서 사전적으로 비교합니다. 내장 컨테이너는 일반적으로 동일한(identical) 객체가 자신과 같다고(equal) 가정합니다. 이를 통해 동일한 객체에 대한 동등성(equality) 검사를 우회하여 성능을 개선하고 내부 불변성을 유지합니다.

내장 컬렉션들의 사전적인 비교는 다음과 같이 이루어집니다:

두 컬렉션이 같다고 비교되기 위해서는, 같은 형이고, 길이가 같고, 대응하는 요소들의 각 쌍이 같다고 비교되어야 합니다 (예를 들어, [1,2] == (1,2) 는 거짓인데, 형이 다르기 때문입니다).

대소 비교를 지원하는 컬렉션들은 첫 번째로 다른 요소들과 같은 순서를 줍니다 (예를 들어, [1,2,x] <= [1,2,y] 는 x <= y 와 같은 값입니다). 대응하는 요소가 없는 경우 더 짧은 컬렉션이 작다고 비교됩니다 (예를 들어, [1,2] < [1,2,3] 은 참입니다).

Mappings (instances of dict) compare equal if and only if they have equal (key, value) pairs. Equality comparison of the keys and values enforces reflexivity.

대소 비교 (<, >, <=, >=) 는 TypeError 를 일으킵니다.

집합들 (set 이나 frozenset 의 인스턴스들)은 같은 형들과 서로 다른 형들 간에 비교될 수 있습니다.

이것들은 부분집합(subset)과 상위집합(superset)을 뜻하는 대소비교 연산자들을 정의합니다. 이 관계는 전 순서(total ordering)를 정의하지 않습니다 (예를 들어, 두 집합 {1,2} 와 {2,3} 는 다르면서도, 하나가 다른 하나의 부분집합이지도, 하나가 다른 하나의 상위집합이지도 않습니다). 따라서, 전 순서에 의존하는 함수의 인자로는 적합하지 않습니다 (예를 들어, min(), max(), sorted() 에 입력으로 집합의 리스트를 제공하면 정의되지 않은 결과를 줍니다).

집합의 비교는 그 요소들의 반사성을 강제합니다.

대부분의 다른 내장형들은 비교 메서드들을 구현하지 않기 때문에, 기본 비교 동작을 계승합니다.

비교 동작을 커스터마이즈하는 사용자 정의 클래스들은 가능하다면 몇 가지 일관성 규칙을 준수해야 합니다:

동등 비교는 반사적(reflexive)이어야 합니다. 다른 말로 표현하면, 아이덴티티가 같은 객체는 같다고 비교되어야 합니다:

x is y 면 x == y 다.

비교는 대칭적(symmetric)이어야 합니다. 다른 말로 표현하면, 다음과 같은 표현식은 같은 결과를 주어야 합니다:

x == y 와 y == x

x != y 와 y != x

x < y 와 y > x

x <= y 와 y >= x

비교는 추이적(transitive)이어야 합니다. 다음 (철저하지 않은) 예들이 이것을 예증합니다:

x > y and y > z 면 x > z 다

x < y and y <= z 면 x < z 다

역 비교는 논리적 부정이 되어야 합니다. 다른 말로 표현하면, 다음 표현식들이 같은 값을 주어야 합니다:

x == y 와 not x != y

x < y 와 not x >= y (전 순서의 경우)

x > y 와 not x <= y (전 순서의 경우)

마지막 두 표현식은 전 순서 컬렉션에 적용됩니다 (예를 들어, 시퀀스에는 적용되지만, 집합과 매핑은 그렇지 않습니다). total_ordering() 데코레이터도 보십시오.

hash() 결과는 동등성과 일관성을 유지해야 합니다. 같은 객체들은 같은 해시값을 같거나 해시 불가능으로 지정되어야 합니다.

파이썬은 이 일관성 규칙들을 강제하지 않습니다. 사실 NaN 값들은 이 규칙을 따르지 않는 예입니다.

6.10.2. 멤버십 검사 연산

연산자 in 과 not in 은 멤버십을 검사합니다. x in s 는 x 가 s 의 멤버일 때 True 를, 그렇지 않을 때 False 를 줍니다. x not in s 은 x in s 의 부정을 줍니다. 딕셔너리 뿐만 아니라 모든 내장 시퀀스들과 집합 형들이 이것을 지원하는데, 딕셔너리의 경우는 in 이 딕셔너리에 주어진 키가 있는지 검사합니다. list, tuple, set, frozenset, dict, collections.deque 와 같은 컨테이너형들의 경우, 표현식 x in y 는 any(x is e or x == e for e in y) 와 동등합니다.

문자열과 바이트열 형의 경우, x in y 는 x 가 y 의 부분 문자열(substring)인 경우, 그리고 오직 그 경우만 True 입니다. 동등한 검사는 y.find(x) != -1 입니다. 빈 문자열은 항상 다른 문자열들의 부분 문자열로 취급되기 때문에, "" in "abc" 은 True 를 돌려줍니다.

For user-defined classes which define the __contains__() method, x in y returns True if y.__contains__(x) returns a true value, and False otherwise.

For user-defined classes which do not define __contains__() but do define __iter__(), x in y is True if some value z, for which the expression x is z or x == z is true, is produced while iterating over y. If an exception is raised during the iteration, it is as if in raised that exception.

Lastly, the old-style iteration protocol is tried: if a class defines __getitem__(), x in y is True if and only if there is a non-negative integer index i such that x is y[i] or x == y[i], and no lower integer index raises the IndexError exception. (If any other exception is raised, it is as if in raised that exception).

연산자 not in 은 in 의 논리적 부정으로 정의됩니다.

6.10.3. 아이덴티티 비교

연산자 is 와 is not 은 객체의 아이덴티티를 검사합니다: x is y 는 x 와 y 가 아이덴티티가 같은 객체일 때, 그리고 오직 그 경우만 참입니다. 객체의 아이덴티티는 id() 함수를 사용해서 결정됩니다. x is not y 은 논리적 부정 값을 줍니다. [4]

6.11. 논리 연산(Boolean operations)

or_test  ::=  and_test | or_test "or" and_test
and_test ::=  not_test | and_test "and" not_test
not_test ::=  comparison | "not" not_test

In the context of Boolean operations, and also when expressions are used by control flow statements, the following values are interpreted as false: False, None, numeric zero of all types, and empty strings and containers (including strings, tuples, lists, dictionaries, sets and frozensets). All other values are interpreted as true. User-defined objects can customize their truth value by providing a __bool__() method.

연산자 not 은 그 인자가 거짓이면 True 를, 그렇지 않으면 False 를 줍니다.

표현식 x and y 는 먼저 x 의 값을 구합니다; x 가 거짓이면 그 값을 돌려줍니다; 그렇지 않으면 y 의 값을 구한 후에 그 결과를 돌려줍니다.

표현식 x or y 는 먼저 x 의 값을 구합니다; x 가 참이면 그 값을 돌려줍니다. 그렇지 않으면 y 의 값을 구한 후에 그 결과를 돌려줍니다.

and 와 or 어느 것도 반환 값이나 그 형을 False 와 True 로 제한하지 않고, 대신 마지막에 값이 구해진 인자를 돌려줌에 주의해야 합니다. 이것은 때로 쓸모가 있습니다, 예를 들어 s 가 문자열이고 비어 있으면 기본값으로 대체되어야 한다면, 표현식 s or 'foo' 는 원하는 값을 제공합니다. not 은 새 값을 만들어야 하므로, 그 인자의 형과 관계없이 논리값(boolean value)을 돌려줍니다 (예를 들어, not 'foo' 는 '' 가 아니라 False 를 만듭니다.)

6.12. 대입 표현식

assignment_expression ::=  [identifier ":="] expression

An assignment expression (sometimes also called a “named expression” or “walrus”) assigns an expression to an identifier, while also returning the value of the expression.

일반적인 사용 사례 중 하나는 일치하는 정규식을 처리할 때입니다:

if matching := pattern.search(data):
    do_something(matching)

또는, 청크로 파일 스트림을 처리할 때:

while chunk := file.read(9000):
    process(chunk)

Assignment expressions must be surrounded by parentheses when used as expression statements and when used as sub-expressions in slicing, conditional, lambda, keyword-argument, and comprehension-if expressions and in assert, with, and assignment statements. In all other places where they can be used, parentheses are not required, including in if and while statements.

Added in version 3.8: 대입 표현식에 대한 더 자세한 내용은 PEP 572 [https://peps.python.org/pep-0572/]를 참조하세요.

6.13. 조건 표현식(Conditional expressions)

conditional_expression ::=  or_test ["if" or_test "else" expression]
expression             ::=  conditional_expression | lambda_expr

조건 표현식은 (때로 “삼 항 연산자(ternary operator)”라고 불립니다) 모든 파이썬 연산에서 가장 낮은 우선순위를 갖습니다.

표현식 x if C else y 은 먼저 x 대신에 조건 C 의 값을 구합니다. C 가 참이면, x 의 값이 구해지고 그 값을 돌려줍니다; 그렇지 않으면, y 의 값을 구한 후에 그 결과를 돌려줍니다.

조건 표현식에 대한 더 자세한 내용은 PEP 308 [https://peps.python.org/pep-0308/] 를 참조하세요.

6.14. 람다(Lambdas)

lambda_expr ::=  "lambda" [parameter_list] ":" expression

람다 표현식은 (때로 람다 형식(lambda forms)이라고 불립니다) 이름 없는 함수를 만드는 데 사용됩니다. 표현식 lambda parameters: expression 는 함수 객체를 줍니다. 이 이름 없는 객체는 이렇게 정의된 함수 객체처럼 동작합니다:

def <lambda>(parameters):
    return expression

매개변수 목록의 문법은 함수 정의 섹션을 보세요. 람다 표현식으로 만들어진 함수는 문장(statements)이나 어노테이션(annotations)을 포함할 수 없음에 주의해야 합니다.

6.15. 표현식 목록(Expression lists)

starred_expression       ::=  ["*"] or_expr
flexible_expression      ::=  assignment_expression | starred_expression
flexible_expression_list ::=  flexible_expression ("," flexible_expression)* [","]
starred_expression_list  ::=  starred_expression ("," starred_expression)* [","]
expression_list          ::=  expression ("," expression)* [","]
yield_list               ::=  expression_list | starred_expression "," [starred_expression_list]

리스트나 집합 디스플레이의 일부일 때를 제외하고, 최소한 하나의 쉼표를 포함하는 표현식 목록은 튜플을 줍니다. 튜플의 길이는 목록에 있는 표현식의 개수입니다. 표현식들은 왼쪽에서 오른쪽으로 값이 구해집니다.

애스터리스크(asterisk) * 는 이터러블 언 패킹(iterable unpacking)을 나타냅니다. 피연산자는 반드시 이터러블 이어야 합니다. 그 이터러블이 항목들의 시퀀스로 확장되어서, 언 패킹 지점에서 새 튜플, 리스트, 집합에 포함됩니다.

Added in version 3.5: 표현식 목록에서의 이터러블 언 패킹, PEP 448 [https://peps.python.org/pep-0448/] 에서 최초로 제안되었습니다.

Added in version 3.11: Any item in an expression list may be starred. See PEP 646 [https://peps.python.org/pep-0646/].

A trailing comma is required only to create a one-item tuple, such as 1,; it is optional in all other cases. A single expression without a trailing comma doesn’t create a tuple, but rather yields the value of that expression. (To create an empty tuple, use an empty pair of parentheses: ().)

6.16. 값을 구하는 순서

파이썬은 왼쪽에서 오른쪽으로 표현식의 값을 구합니다. 대입의 값을 구하는 동안, 우변의 값이 좌변보다 먼저 구해짐에 주목하십시오.

다음 줄들에서, 표현식은 그들의 끝에 붙은 숫자들의 순서대로 값이 구해집니다:

expr1, expr2, expr3, expr4
(expr1, expr2, expr3, expr4)
{expr1: expr2, expr3: expr4}
expr1 + expr2 * (expr3 - expr4)
expr1(expr2, expr3, *expr4, **expr5)
expr3, expr4 = expr1, expr2

6.17. 연산자 우선순위

The following table summarizes the operator precedence in Python, from highest precedence (most binding) to lowest precedence (least binding). Operators in the same box have the same precedence. Unless the syntax is explicitly given, operators are binary. Operators in the same box group left to right (except for exponentiation and conditional expressions, which group from right to left).

비교, 멤버십 검사, 아이덴티티 검사들은 모두 같은 우선순위를 갖고 비교 섹션에서 설명한 것처럼 왼쪽에서 오른쪽으로 이어붙이기(chaining) 하는 기능을 갖습니다.

연산자

설명

(expressions...),

[expressions...], {key: value...}, {expressions...}

결합(binding) 또는 괄호 친 표현식, 리스트 디스플레이, 딕셔너리 디스플레이, 집합 디스플레이

x[index], x[index:index], x(arguments...), x.attribute

서브스크립션, 슬라이싱, 호출, 어트리뷰트 참조

await x

어웨이트 표현식

**

거듭제곱 [5]

+x, -x, ~x

양, 음, 비트 NOT

*, @, /, //, %

곱셈, 행렬 곱셈, 나눗셈, 정수 나눗셈, 나머지 [6]

+, -

덧셈과 뺄셈

<<, >>

시프트

&

비트 AND

^

비트 XOR

|

비트 OR

in, not in, is, is not, <, <=, >, >=, !=, ==

비교, 멤버십 검사와 아이덴티티 검사를 포함합니다

not x

논리 NOT

and

논리 AND

or

논리 OR

if – else

조건 표현식

lambda

람다 표현식

:=

대입 표현식

각주

[1]

abs(x%y) < abs(y) 이 수학적으로는 참이지만, float의 경우에는 소수점 자름(roundoff) 때문에 수치적으로 참이 아닐 수 있습니다. 예를 들어, 파이썬 float가 IEEE 754 배정도 숫자인 플랫폼을 가정할 때, -1e-100 % 1e100 가 1e100 와 같은 부호를 가지기 위해, 계산된 결과는 -1e-100 + 1e100 인데, 수치적으로는 1e100 과 정확히 같은 값입니다. 함수 math.fmod() 는 부호가 첫 번째 인자의 부호에 맞춰진 결과를 주기 때문에, 이 경우 -1e-100 을 돌려줍니다. 어떤 접근법이 더 적절한지는 응용 프로그램에 달려있습니다.

[2]

x가 y의 정확한 정수배와 아주 가까우면, 라운딩(rounding) 때문에 x//y 는 (x-x%y)//y 보다 1 클 수 있습니다. 그런 경우, divmod(x,y)[0] * y + x % y 가 x 와 아주 가깝도록 유지하기 위해, 파이썬은 뒤의 결과를 돌려줍니다.

[3]

유니코드 표준은 코드 포인트(code points) (예를 들어, U+0041) 와 추상 문자(abstract characters) (예를 들어, “LATIN CAPITAL LETTER A”) 를 구분합니다. 유니코드에 있는 대부분의 추상 문자들이 오직 하나의 코드 포인트만으로 표현되지만, 추가로 하나 이상의 코드 포인트의 시퀀스로 표현될 수 있는 추상 문자들이 많이 있습니다. 예를 들어, 추상 문자 “LATIN CAPITAL LETTER C WITH CEDILLA” 는 코드 위치 U+00C7 에 있는 한 개의 복합 문자(precomposed character) 나 코드 위치 U+0043 (LATIN CAPITAL LETTER C) 에 있는 기본 문자(base character) 와 뒤따르는 코드 위치 U+0327 (COMBINING CEDILLA) 에 있는 결합 문자(combining character) 의 시퀀스로 표현될 수 있습니다.

문자열의 비교 연산자는 유니코드 코드 포인트 수준에서 비교합니다. 이것은 사람에게 반 직관적일 수 있습니다. 예를 들어, "\u00C7" == "\u0043\u0327" 는 거짓입니다, 설사 두 문자열이 같은 추상 문자 “LATIN CAPITAL LETTER C WITH CEDILLA”를 표현할지라도 그렇습니다.

문자열을 추상 문자 수준에서 비교하려면 (즉, 사람에게 직관적인 방법으로), unicodedata.normalize() 를 사용하십시오.

[4]

자동 가비지-수거(automatic garbage-collection)와 자유 목록(free lists)과 디스크립터(descriptor)의 동적인 성격 때문에, is 연산자를 인스턴스 메서드들이나 상수들을 비교하는 것과 같은 특정한 방식으로 사용할 때, 겉으로 보기에 이상한 동작을 감지할 수 있습니다. 더 자세한 정보는 그들의 문서를 확인하십시오.

[5]

거듭제곱 연산자 ** 는 오른쪽에 오는 산술이나 비트 일 항 연산자보다 약하게 결합합니다, 즉, 2**-1 는 0.5 입니다.

[6]

% 연산자는 문자열 포매팅에도 사용됩니다; 같은 우선순위가 적용됩니다.

7. 단순문(Simple statements)

단순문은 하나의 논리적인 줄 안에 구성됩니다. 여러 개의 단순문이 세미콜론으로 분리되어 하나의 줄에 나올 수 있습니다. 단순문의 문법은 이렇습니다:

simple_stmt ::=  expression_stmt
                 | assert_stmt
                 | assignment_stmt
                 | augmented_assignment_stmt
                 | annotated_assignment_stmt
                 | pass_stmt
                 | del_stmt
                 | return_stmt
                 | yield_stmt
                 | raise_stmt
                 | break_stmt
                 | continue_stmt
                 | import_stmt
                 | future_stmt
                 | global_stmt
                 | nonlocal_stmt
                 | type_stmt

7.1. 표현식 문

표현식 문은 값을 계산하고 출력하거나, (보통) 프로시저(procedure) (의미 없는 결과를 돌려주는 함수; 파이썬에서 프로시저는 None 값을 돌려줍니다)를 호출하기 위해 (대부분 대화형으로) 사용됩니다. 표현식 문의 다른 사용도 허락되고 때때로 쓸모가 있습니다.

expression_stmt ::=  starred_expression

표현식 문은 (하나의 표현식일 수 있는) 표현식 목록의 값을 구합니다.

대화형 모드에서, 값이 None 이 아니면, 내장 repr() 함수를 사용해 문자열로 변환되고, 그렇게 나온 문자열을 별도의 줄에 표준 출력으로 보냅니다 (결과가 None 일 때는 그렇지 않아서, 프로시저 호출은 어떤 출력도 만들지 않습니다.),

7.2. 대입문

대입문은 이름을 값에 (재)연결하고 가변 객체의 어트리뷰트나 항목들을 수정합니다.

assignment_stmt ::=  (target_list "=")+ (starred_expression | yield_expression)
target_list     ::=  target ("," target)* [","]
target          ::=  identifier
                     | "(" [target_list] ")"
                     | "[" [target_list] "]"
                     | attributeref
                     | subscription
                     | slicing
                     | "*" target

(attributeref, subscription, slicing 의 문법 정의는 프라이머리 섹션을 보십시오.)

대입문은 표현식 목록 (이것이 하나의 표현식일 수도, 쉼표로 분리된 목록일 수도 있는데, 후자의 경우는 튜플이 만들어진다는 것을 기억하십시오) 의 값을 구하고, 왼쪽에서 오른쪽으로, 하나의 결과 객체를 타깃 목록의 각각에 대입합니다.

대입은 타깃 (목록)의 형태에 따라 재귀적으로 정의됩니다. 타깃이 가변 객체의 일부 (어트리뷰트 참조나 서브스크립션이나 슬라이싱) 면, 가변 객체가 최종적으로 대입을 수행해야만 하고, 그것이 올바른지 아닌지를 결정하고, 대입이 받아들여 질 수 없으면 예외를 일으킬 수 있습니다. 다양한 형들이 주시하는 규칙들과 발생하는 예외들은 그 객체 형의 정의에서 주어진다 (표준형 계층 섹션을 보십시오).

객체를 타깃 목록, 괄호나 대괄호로 둘러싸일 수 있는데 생략할 수 있습니다, 에 대입하는 것은 다음과 같이 재귀적으로 정의됩니다.

타깃 목록이 (선택적으로 괄호에 들어있는) 뒤따르는 쉼표가 없는 하나의 타깃이면 객체는 타깃에 대입됩니다.

Else:

타깃 목록이 애스터리스크(asterisk)를 앞에 붙인 타깃, “스타드(starred)” 타깃이라고 불립니다, 하나를 포함하면: 객체는 적어도 타깃 목록에 나오는 타깃의 수보다 하나 작은 개수의 항목을 제공하는 이터러블이어야 합니다. 이터러블의 처음 항목들은, 왼쪽에서 오른쪽으로, 스타드 타깃 앞에 나오는 타깃들에 대입됩니다. 이터러블의 마지막 항목들은 스타드 타깃 뒤에 나오는 타깃들에 대입됩니다. 이터러블의 나머지 항목들로 구성된 리스트가 스타드 타깃에 대입됩니다 (이 리스트는 비어있을 수 있습니다).

그렇지 않으면: 객체는 타깃 목록에 나오는 타깃의 수와 같은 수의 항목들을 제공하는 이터러블이어야 하고, 항목들은, 왼쪽에서 오른쪽으로, 대응하는 타깃들에 대입됩니다.

하나의 타깃에 대한 객체의 대입은 다음과 같이 재귀적으로 정의됩니다.

타깃이 식별자 (이름) 면:

그 이름이 현재 코드 블록에 있는 global 나 nonlocal 문에 등장하지 않으면: 그 이름은 현재 지역 이름 공간에서 객체에 연결됩니다.

그렇지 않으면: 그 이름은 각각 전역 이름 공간이나 nonlocal 에 의해 결정되는 외부 이름 공간에서 객체에 연결됩니다.

그 이름이 이미 연결되어 있으면 재연결됩니다. 이것은 기존에 연결되어 있던 객체의 참조 횟수가 0이 되도록 만들어서, 객체가 점유하던 메모리가 반납되고 파괴자(destructor) (갖고 있다면) 가 호출되도록 만들 수 있습니다.

타깃이 어트리뷰트 참조면: 참조의 프라이머리 표현식의 값을 구합니다. 이것은 대입 가능한 어트리뷰트를 가진 객체를 주어야 하는데, 그렇지 않으면 TypeError 가 일어납니다. 그에 그 객체에 주어진 어트리뷰트로 객체를 대입하도록 요청합니다; 대입을 수행할 수 없다면 예외 (보통 AttributeError 이지만, 꼭 그럴 필요는 없다) 를 일으킵니다.

주의 사항: 객체가 클래스 인스턴스이고 어트리뷰트 참조가 대입 연산자의 양쪽에서 모두 등장하면, 우변(right-hand side) 표현식, a.x 는 인스턴스 어트리뷰트나 (인스턴스 어트리뷰트가 없다면) 클래스 어트리뷰트를 액세스할 수 있습니다. 좌변(left-hand side) 타깃 a.x 는 항상 필요하면 만들어서라도 항상 인스턴스 어트리뷰트를 설정합니다. 그래서, 두 a.x 가 같은 어트리뷰트를 가리키는 것은 필요조건이 아닙니다: 우변 표현식이 클래스 어트리뷰트를 가리킨다면, 좌변은 대입의 타깃으로 새 인스턴스 어트리뷰트를 만듭니다:

class Cls:
    x = 3             # class variable
inst = Cls()
inst.x = inst.x + 1   # writes inst.x as 4 leaving Cls.x as 3

이 설명이 property() 로 만들어진 프로퍼티(property)와 같은 디스크립터 어트리뷰트에 적용될 필요는 없습니다.

타깃이 서브스크립션이면: 참조에 있는 프라이머리 표현식의 값을 구합니다. (리스트 같은) 가변 시퀀스 객체나 (딕셔너리 같은) 매핑 객체가 나와야 합니다. 그런 다음, 서브 스크립트 표현식의 값을 구합니다.

프라이머리가 (리스트 같은) 가변 시퀀스 객체면, 서브 스크립트는 정수가 나와야 합니다. 음수면, 시퀀스의 길이가 더해집니다. 결괏값은 시퀀스의 길이보다 작은 음이 아닌 정수여야 하고, 시퀀스에 그 인덱스를 가진 항목에 객체를 대입하라고 요청합니다. 인덱스가 범위를 벗어나면, IndexError 를 일으킵니다 (서브 스크립트 된 시퀀스에 대한 대입은 리스트에 새 항목을 추가할 수 없습니다).

If the primary is a mapping object (such as a dictionary), the subscript must have a type compatible with the mapping’s key type, and the mapping is then asked to create a key/value pair which maps the subscript to the assigned object. This can either replace an existing key/value pair with the same key value, or insert a new key/value pair (if no key with the same value existed).

For user-defined objects, the __setitem__() method is called with appropriate arguments.

타깃이 슬라이싱이면: 참조의 프라이머리 표현식의 값을 구합니다. (리스트 같은) 가변 시퀀스 객체가 나와야 합니다. 대입되는 객체는 같은 형의 시퀀스 객체야 합니다. 그런 다음, 존재한다면 하한과 상한 표현식의 값을 구합니다; 기본값은 0과 시퀀스의 길이다. 경곗값은 정수가 되어야 합니다. 둘 중 어느 것이건 음수가 나오면, 시퀀스의 길이를 더합니다. 그렇게 얻어진 경곗값들을 0과 시퀀스의 길이나 그 사이에 들어가는 값이 되도록 자릅니다. 마지막으로 시퀀스 객체에 슬라이스를 대입되는 시퀀스로 변경하도록 요청합니다. 타깃 시퀀스가 허락한다면, 슬라이스의 길이는 대입되는 시퀀스의 길이와 다를 수 있습니다.

CPython 구현 상세: 현재 구현에서, 타깃의 문법은 표현식과 같게 유지되고, 잘못된 문법은 코드 생성 단계에서 거부되기 때문에 에러 메시지가 덜 상세해지는 결과를 낳고 있습니다.

설사 대입의 정의가 좌변과 우변 간의 중첩이 ‘동시적(simultaneous)’임을 (예를 들어, a, b = b, a 는 두 변수를 교환합니다) 암시해도, 대입되는 변수들의 컬렉션 안 에서의 중첩은 왼쪽에서 오른쪽으로 일어나서, 때로 혼동할 수 있는 결과를 낳습니다. 예를 들어, 다음과 같은 프로그램은 [0, 2] 를 인쇄합니다:

x = [0, 1]
i = 0
i, x[i] = 1, 2         # i is updated, then x[i] is updated
print(x)

더 보기

PEP 3132 [https://peps.python.org/pep-3132/] - 확장 이터러블 언 패킹

*target 기능에 대한 규격

7.2.1. 증분 대입문(Augmented assignment statements)

증분 대입문은 한 문장에서 이항 연산과 대입문을 합치는 것입니다:

augmented_assignment_stmt ::=  augtarget augop (expression_list | yield_expression)
augtarget                 ::=  identifier | attributeref | subscription | slicing
augop                     ::=  "+=" | "-=" | "*=" | "@=" | "/=" | "//=" | "%=" | "**="
                               | ">>=" | "<<=" | "&=" | "^=" | "|="

(마지막 세 기호의 문법 정의는 프라이머리 섹션을 보십시오.)

증분 대입은 타깃 (일반 대입문과는 달리 언 패킹이 될 수 없습니다) 과 표현식 목록의 값을 구하고, 둘을 피연산자로 삼아 대입의 형에 맞는 이항 연산을 수행한 후, 원래의 타깃에 그 결과를 대입합니다. 타깃은 오직 한 번만 값이 구해집니다.

An augmented assignment statement like x += 1 can be rewritten as x = x + 1 to achieve a similar, but not exactly equal effect. In the augmented version, x is only evaluated once. Also, when possible, the actual operation is performed in-place, meaning that rather than creating a new object and assigning that to the target, the old object is modified instead.

일반 대입과는 달리, 증분 대입은 우변의 값을 구하기 이전에 좌변의 값을 구합니다. 예를 들어, a[i] += f(x) 는 처음에 a[i] 를 조회한 다음, f(x) 의 값을 구하고, 덧셈을 수행하고, 마지막으로 그 결과를 a[i] 에 다시 씁니다.

하나의 문장에서 튜플과 다중 타깃으로 대입하는 것을 예외로 하면, 증분 대입문에 의한 대입은 일반 대입과 같은 방법으로 처리됩니다. 마찬가지로, 제자리 동작의 가능성을 예외로 하면, 증분 대입 때문에 수행되는 이진 연산은 일반 이진 연산과 같습니다.

어트리뷰트 참조인 타깃의 경우, 일반 대입처럼 클래스와 인스턴스 어트리뷰트에 관한 경고 가 적용됩니다.

7.2.2. 어노테이트된 대입문(Annotated assignment statements)

어노테이션 대입은, 한 문장에서, 변수나 어트리뷰트 어노테이션과 생략할 수 있는 대입문을 합치는 것입니다.

annotated_assignment_stmt ::=  augtarget ":" expression
                               ["=" (starred_expression | yield_expression)]

The difference from normal 대입문 is that only a single target is allowed.

The assignment target is considered “simple” if it consists of a single name that is not enclosed in parentheses. For simple assignment targets, if in class or module scope, the annotations are gathered in a lazily evaluated annotation scope. The annotations can be evaluated using the __annotations__ attribute of a class or module, or using the facilities in the annotationlib module.

If the assignment target is not simple (an attribute, subscript node, or parenthesized name), the annotation is never evaluated.

이름이 함수 스코프에서 어노테이트되면, 이 이름은 그 스코프에 지역적(local)입니다. 함수 스코프에서 어노테이션은 값이 구해지거나 저장되지 않습니다.

If the right hand side is present, an annotated assignment performs the actual assignment as if there was no annotation present. If the right hand side is not present for an expression target, then the interpreter evaluates the target except for the last __setitem__() or __setattr__() call.

더 보기

PEP 526 [https://peps.python.org/pep-0526/] - 변수 어노테이션 문법

주석을 통해 표현하는 대신, 변수(클래스 변수와 인스턴스 변수 포함)의 형을 어노테이트 하는 문법을 추가하는 제안.

PEP 484 [https://peps.python.org/pep-0484/] - 형 힌트

정적 분석 도구와 IDE에서 사용할 수 있는 형 어노테이션에 대한 표준 문법을 제공하기 위해 typing 모듈을 추가하는 제안.

버전 3.8에서 변경: Now annotated assignments allow the same expressions in the right hand side as regular assignments. Previously, some expressions (like un-parenthesized tuple expressions) caused a syntax error.

버전 3.14에서 변경: Annotations are now lazily evaluated in a separate annotation scope. If the assignment target is not simple, annotations are never evaluated.

7.3. assert 문

assert 문은 프로그램에 디버깅 어서션(debugging assertion)을 삽입하는 편리한 방법입니다:

assert_stmt ::=  "assert" expression ["," expression]

간단한 형태, assert expression 은 다음과 동등합니다

if __debug__:
    if not expression: raise AssertionError

확장된 형태, assert expression1, expression2 는 다음과 동등합니다

if __debug__:
    if not expression1: raise AssertionError(expression2)

These equivalences assume that __debug__ and AssertionError refer to the built-in variables with those names. In the current implementation, the built-in variable __debug__ is True under normal circumstances, False when optimization is requested (command line option -O). The current code generator emits no code for an assert statement when optimization is requested at compile time. Note that it is unnecessary to include the source code for the expression that failed in the error message; it will be displayed as part of the stack trace.

__debug__ 에 대한 대입은 허락되지 않습니다. 이 내장 변수의 값은 인터프리터가 시작할 때 결정됩니다.

7.4. pass 문

pass_stmt ::=  "pass"

pass 는 널(null) 연산입니다 — 실행될 때, 아무런 일도 일어나지 않습니다. 문법적으로 문장이 필요하기는 하지만 할 일은 없을 때, 자리를 채우는 용도로 쓸모가 있습니다, 예를 들어:

def f(arg): pass    # a function that does nothing (yet)

class C: pass       # a class with no methods (yet)

7.5. del 문

del_stmt ::=  "del" target_list

삭제는 대입이 정의된 방식과 아주 비슷하게 재귀적으로 정의됩니다. 전체 세부 사항들을 나열하는 대신, 여기 몇 가지 힌트가 있습니다.

타깃 목록의 삭제는 각 타깃을 왼쪽에서 오른쪽으로 재귀적으로 삭제합니다.

이름의 삭제는 같은 코드 블록에 있는 global 문에 그 이름이 등장하는지에 따라 지역이나 전역 이름 공간에서 이름의 연결을 제거합니다. 이름이 연결되어 있지 않으면, NameError 예외가 일어납니다.

어트리뷰트 참조, 서브스크립션, 슬라이싱의 삭제는 관련된 프라이머리 객체로 전달됩니다; 슬라이싱의 삭제는 일반적으로 우변 형의 빈 슬라이스를 대입하는 것과 동등합니다 (하지만 이것조차 슬라이싱 되는 객체가 판단합니다).

버전 3.2에서 변경: 예전에는 이름이 중첩된 블록에서 자유 변수로 등장하는 경우 지역 이름 공간에서 삭제하는 것이 허락되지 않았습니다.

7.6. return 문

return_stmt ::=  "return" [expression_list]

return 은 문법적으로 클래스 정의에 중첩된 경우가 아니라, 함수 정의에만 중첩되어 나타날 수 있습니다.

표현식 목록이 있으면 값을 구하고, 그렇지 않으면 None 으로 치환됩니다.

return 은 표현식 목록 (또는 None)을 반환 값으로 해서, 현재의 함수 호출을 떠납니다.

return 이 finally 절을 가진 try 문에서 제어가 벗어나도록 만드는 경우, 함수로부터 진짜로 벗어나기 전에 그 finally 절이 실행됩니다.

제너레이터 함수에서, return 문은 제너레이터가 끝났음을 가리키고, StopIteration 예외를 일으킵니다. return 문에 제공되는 값은 (있다면) StopIteration 의 생성자에 인자로 전달되어 StopIteration.value 어트리뷰트가 됩니다.

비동기 제너레이터 함수에서, 빈 return 문은 비동기 제너레이터가 끝났음을 알리고, StopAsyncIteration 예외를 일으킵니다. 비동기 제너레이터 함수에서, 비어있지 않은 return 은 문법 에러입니다.

7.7. yield 문

yield_stmt ::=  yield_expression

A yield statement is semantically equivalent to a yield expression. The yield statement can be used to omit the parentheses that would otherwise be required in the equivalent yield expression statement. For example, the yield statements

yield <expr>
yield from <expr>

은 다음과 같은 yield 표현식 문장들과 동등합니다

(yield <expr>)
(yield from <expr>)

Yield expressions and statements are only used when defining a generator function, and are only used in the body of the generator function. Using yield in a function definition is sufficient to cause that definition to create a generator function instead of a normal function.

yield 의 뜻에 대한 전체 세부 사항들은 일드 표현식(Yield expressions) 섹션을 참고하면 됩니다.

7.8. raise 문

raise_stmt ::=  "raise" [expression ["from" expression]]

If no expressions are present, raise re-raises the exception that is currently being handled, which is also known as the active exception. If there isn’t currently an active exception, a RuntimeError exception is raised indicating that this is an error.

그렇지 않으면, raise 는 예외 객체로, 첫 번째 표현식의 값을 구합니다. BaseException 의 서브 클래스나 인스턴스여야 합니다. 클래스면, 예외 인스턴스는 필요할 때 인자 없이 클래스의 인스턴스를 만들어서 사용됩니다.

예외의 형(type)은 예외 인스턴스의 클래스고, 값(value)은 인스턴스 자신입니다.

A traceback object is normally created automatically when an exception is raised and attached to it as the __traceback__ attribute. You can create an exception and set your own traceback in one step using the with_traceback() exception method (which returns the same exception instance, with its traceback set to its argument), like so:

raise Exception("foo occurred").with_traceback(tracebackobj)

The from clause is used for exception chaining: if given, the second expression must be another exception class or instance. If the second expression is an exception instance, it will be attached to the raised exception as the __cause__ attribute (which is writable). If the expression is an exception class, the class will be instantiated and the resulting exception instance will be attached to the raised exception as the __cause__ attribute. If the raised exception is not handled, both exceptions will be printed:

>>> try:
...     print(1 / 0)
... except Exception as exc:
...     raise RuntimeError("Something bad happened") from exc
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    print(1 / 0)
          ~~^~~
ZeroDivisionError: division by zero

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
    raise RuntimeError("Something bad happened") from exc
RuntimeError: Something bad happened

A similar mechanism works implicitly if a new exception is raised when an exception is already being handled. An exception may be handled when an except or finally clause, or a with statement, is used. The previous exception is then attached as the new exception’s __context__ attribute:

>>> try:
...     print(1 / 0)
... except:
...     raise RuntimeError("Something bad happened")
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    print(1 / 0)
          ~~^~~
ZeroDivisionError: division by zero

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
    raise RuntimeError("Something bad happened")
RuntimeError: Something bad happened

Exception chaining can be explicitly suppressed by specifying None in the from clause:

>>> try:
...     print(1 / 0)
... except:
...     raise RuntimeError("Something bad happened") from None
...
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
RuntimeError: Something bad happened

예외에 대한 더 많은 정보를 예외 섹션에서 발견할 수 있고, 예외를 처리하는 것에 대한 정보는 try 문 섹션에 있습니다.

버전 3.3에서 변경: 이제 raise X from Y 에서 Y 로 None 이 허락됩니다.

Added the __suppress_context__ attribute to suppress automatic display of the exception context.

버전 3.11에서 변경: If the traceback of the active exception is modified in an except clause, a subsequent raise statement re-raises the exception with the modified traceback. Previously, the exception was re-raised with the traceback it had when it was caught.

7.9. break 문

break_stmt ::=  "break"

break 는 문법적으로 for 나 while 루프에 중첩되어서만 나타날 수 있습니다. 하지만 그 루프 안의 함수나 클래스 정의에 중첩되지는 않습니다.

가장 가까이서 둘러싸고 있는 루프를 종료하고, 그 루프가 else 절을 갖고 있다면 건너뜁니다(skip).

for 루프가 break 로 종료되면, 루프 제어 타깃은 현재값을 유지합니다.

break 가 finally 절을 가 try 문에서 제어가 벗어나도록 만드는 경우, 루프로부터 진짜로 벗어나기 전에 그 finally 절이 실행됩니다.

7.10. continue 문

continue_stmt ::=  "continue"

continue 는 문법적으로 for 나 while 루프에 중첩되어서만 나타날 수 있습니다. 하지만 그 루프 안의 함수나 클래스 정의에 중첩되지는 않습니다. 가장 가까이서 둘러싸고 있는 루프가 다음 사이클로 넘어가도록 만듭니다.

continue 가 finally 절을 가진 try 문에서 제어가 벗어나도록 만드는 경우, 다음 루트 사이클을 시작하기 전에 그 finally 절이 실행됩니다.

7.11. 임포트(import) 문

import_stmt     ::=  "import" module ["as" identifier] ("," module ["as" identifier])*
                     | "from" relative_module "import" identifier ["as" identifier]
                     ("," identifier ["as" identifier])*
                     | "from" relative_module "import" "(" identifier ["as" identifier]
                     ("," identifier ["as" identifier])* [","] ")"
                     | "from" relative_module "import" "*"
module          ::=  (identifier ".")* identifier
relative_module ::=  "."* module | "."+

(from 절이 없는) 기본 임포트 문은 두 단계로 실행됩니다:

모듈을 찾고, 로드하고, 필요하면 초기화합니다

임포트(import) 문이 등장한 스코프의 지역 이름 공간에 이름이나 이름들을 정의합니다.

문장이 (쉼표로 분리된) 여러 개의 절을 포함하면, 마치 각 절이 별도의 임포트 문에 의해 분리된 것처럼, 두 단계는 절마다 별도로 수행됩니다.

The details of the first step, finding and loading modules, are described in greater detail in the section on the import system, which also describes the various types of packages and modules that can be imported, as well as all the hooks that can be used to customize the import system. Note that failures in this step may indicate either that the module could not be located, or that an error occurred while initializing the module, which includes execution of the module’s code.

요청된 모듈이 성공적으로 읽어 들여지면, 세 가지 중 한 방법으로 지역 이름 공간에 소개됩니다:

모듈 이름 뒤에 as 가 오면, as 뒤에 오는 이름이 임포트된 모듈에 직접 연결됩니다.

다른 이름이 지정되지 않고, 임포트되는 모듈이 최상위 모듈이면, 모듈의 이름이 임포트되는 모듈에 대한 참조로 지역 이름 공간에 연결됩니다.

임포트되는 모듈이 최상이 모듈이 아니 라면, 그 모듈을 포함하는 최상위 패키지의 이름이 최상위 패키지에 대한 참조로 지역 이름 공간에 연결됩니다. 임포트된 모듈은 직접적이기보다는 완전히 정규화된 이름(full qualified name)을 통해 액세스 되어야 합니다.

from 형은 약간 더 복잡한 절차를 사용합니다:

from 절에 지정된 모듈을 찾고, 로드하고, 필요하면 초기화합니다

import 절에 지정된 식별자들 각각에 대해:

임포트된 모듈이 그 이름의 어트리뷰트를 가졌는지 검사합니다

없으면, 그 이름의 서브 모듈을 임포트하는 것을 시도한 다음 임포트된 모듈에서 그 어트리뷰트를 다시 검사합니다

어트리뷰트가 발견되지 않으면 ImportError 를 일으킵니다.

그렇지 않으면, 그 값에 대한 참조가 지역 이름 공간에 저장되는데, as 절이 존재하면 거기에서 지정된 이름을 사용하고, 그렇지 않으면 어트리뷰트 이름을 사용합니다

사용 예:

import foo                 # foo imported and bound locally
import foo.bar.baz         # foo, foo.bar, and foo.bar.baz imported, foo bound locally
import foo.bar.baz as fbb  # foo, foo.bar, and foo.bar.baz imported, foo.bar.baz bound as fbb
from foo.bar import baz    # foo, foo.bar, and foo.bar.baz imported, foo.bar.baz bound as baz
from foo import attr       # foo imported and foo.attr bound as attr

식별자들의 목록을 스타 ('*') 로 바꾸면, 모듈에 정의된 모든 공개 이름들이 import 문이 등장한 스코프의 지역 이름 공간에 연결됩니다.

모듈에 정의된 공개 이름(public names) 은 모듈의 이름 공간에서 __all__ 이라는 이름의 변수를 검사해서 결정됩니다; 정의되어 있다면, 문자열의 시퀀스여야 하는데, 그 모듈이 정의하거나 임포트하는 이름들입니다. __all__ 에서 지정한 이름들은 모두 공개로 취급되고 반드시 존재해야 합니다. __all__ 이 정의되지 않으면, 모듈의 이름 공간에서 발견되는 이름 중, 밑줄 문자 ('_')로 시작하지 않는 모든 이름이 공개로 취급됩니다. __all__ 는 공개 API 전체를 포함해야 합니다. 이것의 목적은 의도치 않게 API 일부가 아닌 항목들을 노출하는 것을 방지하는 것입니다 (가령 그 모듈이 임포트하고 사용하는 라이브러리 모듈).

임포트의 와일드카드 형태 — from module import * — 는 모듈 수준에서만 허락됩니다. 클래스나 함수 정의에서 사용하려는 시도는 SyntaxError 를 일으킵니다.

임포트할 모듈을 지정할 때 모듈의 절대 이름(absolute name)을 지정할 필요는 없습니다. 모듈이나 패키지가 다른 패키지 안에 포함될 때, 같은 상위 패키지 내에서는 그 패키지 이름을 언급할 필요 없이 상대 임포트(relative import)를 할 수 있습니다. from 뒤에 지정되는 패키지나 모듈 앞에 붙이는 점으로, 정확한 이름을 지정하지 않고도 현재 패키지 계층을 얼마나 거슬러 올라가야 하는지 지정할 수 있습니다. 하나의 점은 이 임포트를 하는 모듈이 존재하는 현재 패키지를 뜻합니다. 두 개의 점은 한 패키지 수준을 거슬러 올라가는 것을 뜻합니다. 세 개의 점은 두 개의 수준을, 등등입니다. 그래서 pkg 패키지에 있는 모듈에서 from . import mod 를 실행하면, pkg.mod 를 임포트하게 됩니다. pkg.subpkg1 안에서 from ..subpkg2 import mod 를 실행하면 pkg.subpkg2.mod 를 임포트하게 됩니다. 상대 임포트에 대한 규격은 패키지 상대 임포트 절에 들어있습니다.

로드할 모듈들을 동적으로 결정하는 응용 프로그램들을 지원하기 위해 importlib.import_module() 이 제공됩니다.

인자 module, filename, sys.path, sys.meta_path, sys.path_hooks로 감사 이벤트 import를 발생시킵니다.

7.11.1. 퓨처 문

퓨처 문(future statement)은 컴파일러가 특정한 모듈을 특별한 문법이나 개념을 사용해서 컴파일하도록 만드는 지시어(directive)인데, 그 기능은 미래에 출시되는 파이썬에서 표준이 되는 것입니다.

퓨처 문의 목적은 언어에 호환되지 않는 변경이 도입된 미래 버전의 파이썬으로 옮겨가는 것을 쉽게 만드는 것입니다. 그 기능이 표준이 되는 배포 이전에 모듈 단위로 새 기능을 사용할 수 있도록 만듭니다.

future_stmt ::=  "from" "__future__" "import" feature ["as" identifier]
                 ("," feature ["as" identifier])*
                 | "from" "__future__" "import" "(" feature ["as" identifier]
                 ("," feature ["as" identifier])* [","] ")"
feature     ::=  identifier

퓨처 문은 모듈의 거의 처음에 나와야 합니다. 퓨처 문 앞에 나올 수 있는 줄들은:

모듈 독스트링(docstring) (있다면),

주석

빈 줄, 그리고

다른 퓨처 문들

퓨처 문을 사용해야 하는 유일한 기능은 annotations 입니다 (PEP 563 [https://peps.python.org/pep-0563/]을 참조하십시오).

과거에 퓨처 문을 통해 활성화되던 기능들은 여전히 파이썬 3에 의해 인식됩니다. 이 목록에는 absolute_import, division, generators, generator_stop, unicode_literals, print_function, nested_scopes 및 with_statement 가 포함됩니다. 이것들은 잉여물인데 항상 활성화되고, 오직 과거 호환성을 위해 유지되고 있기 때문입니다.

퓨처 문은 구체적으로는 컴파일 시점에 인식되고 다뤄집니다: 핵심 구성물들의 의미에 대한 변경은 종종 다른 코드 생성을 통해 구현됩니다. 새 기능이 호환되지 않는 (새로운 예약어처럼) 새로운 문법을 도입하는 경우조차 가능한데, 이 경우는 컴파일러가 모듈을 다르게 파싱할 수 있습니다. 그런 결정들은 실행 시점으로 미뤄질 수 없습니다..

배포마다, 컴파일러는 어떤 기능 이름들이 정의되어 있는지 알고, 만약 퓨처 문이 알지 못하는 기능을 포함하고 있으면 컴파일 시점 에러를 일으킵니다.

직접적인 실행 시점의 개념은 다른 임포트 문들과 같습니다: 표준 모듈 __future__, 후에 설명합니다, 다 있고, 퓨처 문이 실행되는 시점에 일반적인 방법으로 임포트됩니다.

흥미로운 실행 시점의 개념들은 퓨처 문에 의해 활성화되는 구체적인 기능들에 달려있습니다.

이런 문장에는 아무것도 특별한 것이 없음에 주의해야 합니다:

import __future__ [as name]

이것은 퓨처 문이 아닙니다; 아무런 특별한 개념이나 문법적인 제약이 없는 평범한 임포트 문일 뿐입니다.

Code compiled by calls to the built-in functions exec() and compile() that occur in a module M containing a future statement will, by default, use the new syntax or semantics associated with the future statement. This can be controlled by optional arguments to compile() — see the documentation of that function for details.

대화형 인터프리터 프롬프트에서 입력된 퓨처 문은 인터프리터 세션의 남은 기간 효과를 발생시킵니다. 인터프리터가 -i, 실행할 스크립트 이름이 전달됩니다, 옵션으로 시작하고, 그 스크립트가 퓨처 문을 포함하면, 스크립트가 실행된 이후에 시작되는 대화형 세션에서도 효과를 유지합니다.

더 보기

PEP 236 [https://peps.python.org/pep-0236/] - 백 투 더 __future__

__future__ 메커니즘에 대한 최초의 제안.

7.12. global 문

global_stmt ::=  "global" identifier ("," identifier)*

The global statement causes the listed identifiers to be interpreted as globals. It would be impossible to assign to a global variable without global, although free variables may refer to globals without being declared global.

The global statement applies to the entire scope of a function or class body. A SyntaxError is raised if a variable is used or assigned to prior to its global declaration in the scope.

프로그래머의 주의 사향: global 은 파서에 주는 지시자(directive)입니다. global 문과 같은 시점에 파싱되는 코드에만 적용됩니다. 특히, 내장 exec() 함수로 공급되는 문자열이나 코드 객체에 포함된 global 문은 그 함수 호출을 포함하는 코드 블록에는 영향을 주지 않고, 그런 문자열에 포함된 코드 역시 함수 호출을 포함하는 코드에 있는 global 문에 영향을 받지 않습니다. eval() 과 compile() 함수들도 마찬가지입니다.

7.13. nonlocal 문

nonlocal_stmt ::=  "nonlocal" identifier ("," identifier)*

When the definition of a function or class is nested (enclosed) within the definitions of other functions, its nonlocal scopes are the local scopes of the enclosing functions. The nonlocal statement causes the listed identifiers to refer to names previously bound in nonlocal scopes. It allows encapsulated code to rebind such nonlocal identifiers. If a name is bound in more than one nonlocal scope, the nearest binding is used. If a name is not bound in any nonlocal scope, or if there is no nonlocal scope, a SyntaxError is raised.

The nonlocal statement applies to the entire scope of a function or class body. A SyntaxError is raised if a variable is used or assigned to prior to its nonlocal declaration in the scope.

더 보기

PEP 3104 [https://peps.python.org/pep-3104/] - 바깥 스코프에 있는 이름들에 대한 액세스

nonlocal 문의 규격.

Programmer’s note: nonlocal is a directive to the parser and applies only to code parsed along with it. See the note for the global statement.

7.14. The type statement

type_stmt ::=  'type' identifier [type_params] "=" expression

The type statement declares a type alias, which is an instance of typing.TypeAliasType.

For example, the following statement creates a type alias:

type Point = tuple[float, float]

This code is roughly equivalent to:

annotation-def VALUE_OF_Point():
    return tuple[float, float]
Point = typing.TypeAliasType("Point", VALUE_OF_Point())

annotation-def indicates an annotation scope, which behaves mostly like a function, but with several small differences.

The value of the type alias is evaluated in the annotation scope. It is not evaluated when the type alias is created, but only when the value is accessed through the type alias’s __value__ attribute (see Lazy evaluation). This allows the type alias to refer to names that are not yet defined.

Type aliases may be made generic by adding a type parameter list after the name. See Generic type aliases for more.

type is a soft keyword.

Added in version 3.12.

더 보기

PEP 695 [https://peps.python.org/pep-0695/] - Type Parameter Syntax

Introduced the type statement and syntax for generic classes and functions.

8. 복합문(Compound statements)

복합문은 다른 문장들(의 그룹들)을 포함합니다; 어떤 방법으로 그 다른 문장들의 실행에 영향을 주거나 제어합니다. 간단하게 표현할 때, 전체 복합문을 한 줄로 쓸 수 있기는 하지만, 일반적으로 복합문은 여러 줄에 걸칩니다.

if, while, for 문장은 전통적인 제어 흐름 구조를 구현합니다. 문장들의 그룹에 대해 try 는 예외 처리기나 정리(cleanup) 코드 또는 그 둘 모두를 지정하는 반면, with 문은 코드 블록 주변으로 초기화와 파이널리제이션 코드를 실행할 수 있도록 합니다. 함수와 클래스 정의 또한 문법적으로 복합문입니다.

복합문은 하나나 그 이상의 ‘절’로 구성됩니다. 절은 헤더와 ‘스위트(suite)’로 구성됩니다. 특정 복합문의 절 헤더들은 모두 같은 들여쓰기 수준을 갖습니다. 각 절 헤더는 특별하게 식별되는 키워드로 시작하고 콜론으로 끝납니다. 스위트는 절에 의해 제어되는 문장들의 그룹입니다. 스위트는 헤더의 콜론 뒤에서 같은 줄에 세미콜론으로 분리된 하나나 그 이상의 단순문일 수 있습니다. 또는 그다음 줄에 들여쓰기 된 하나나 그 이상의 문장들일 수도 있습니다. 오직 후자의 형태만 중첩된 복합문을 포함할 수 있습니다; 다음과 같은 것은 올바르지 않은데, 대체로 뒤따르는 else 절이 있다면 어떤 if 절에 속하는지 명확하지 않기 때문입니다.

if test1: if test2: print(x)

또한, 이 문맥에서 세미콜론이 콜론보다 더 강하게 결합해서, 다음과 같은 예에서, print() 호출들은 모두 실행되거나 어느 하나도 실행되지 않습니다는 것에 주의해야 합니다:

if x < y < z: print(x); print(y); print(z)

요약하면:

compound_stmt ::=  if_stmt
                   | while_stmt
                   | for_stmt
                   | try_stmt
                   | with_stmt
                   | match_stmt
                   | funcdef
                   | classdef
                   | async_with_stmt
                   | async_for_stmt
                   | async_funcdef
suite         ::=  stmt_list NEWLINE | NEWLINE INDENT statement+ DEDENT
statement     ::=  stmt_list NEWLINE | compound_stmt
stmt_list     ::=  simple_stmt (";" simple_stmt)* [";"]

문장들이 항상 NEWLINE 으로 끝나고 DEDENT 가 그 뒤를 따를 수 있음에 주목해야 합니다. 또한, 생략 가능한 연결 절들이 항상 문장을 시작시킬 수 없는 키워드로 시작하기 때문에, 모호함이 없다는 것도 주목하세요 (파이썬에서는 중첩된 if 문이 들여쓰기 되는 것을 요구함으로써 ‘매달린(dangling) else’ 문제를 해결합니다).

명확함을 위해 다음에 오는 절들에서 나오는 문법 규칙들은 각 절을 별도의 줄에 놓도록 포매팅합니다.

8.1. if 문

if 문은 조건부 실행에 사용됩니다:

if_stmt ::=  "if" assignment_expression ":" suite
             ("elif" assignment_expression ":" suite)*
             ["else" ":" suite]

참이 되는 것을 발견할 때까지 표현식들의 값을 하나씩 차례대로 구해서 정확히 하나의 스위트를 선택합니다 (참과 거짓의 정의는 논리 연산(Boolean operations) 섹션을 보세요); 그런 다음 그 스위트를 실행합니다 (그리고는 if 문의 다른 어떤 부분도 실행되거나 값이 구해지지 않습니다). 모든 표현식들이 거짓이면 else 절의 스위트가 (있다면) 실행됩니다.

8.2. while 문

while 문은 표현식이 참인 동안 실행을 반복하는 데 사용됩니다:

while_stmt ::=  "while" assignment_expression ":" suite
                ["else" ":" suite]

이것은 표현식을 반복적으로 검사하고, 참이면, 첫 번째 스위트를 실행합니다; 표현식이 거짓이면 (처음부터 거짓일 수도 있습니다) else 절의 스위트가 (있다면) 실행되고 루프를 종료합니다.

첫 번째 스위트에서 실행되는 break 문은 else 절을 실행하지 않고 루프를 종료합니다. 첫 번째 스위트에서 실행되는 continue 문은 스위트의 나머지 부분을 건너뛰고 표현식의 검사로 돌아갑니다.

8.3. for 문

for 문은 (문자열, 튜플, 리스트 같은) 시퀀스 나 다른 이터러블 객체의 요소들을 이터레이트하는데 사용됩니다:

for_stmt ::=  "for" target_list "in" starred_list ":" suite
              ["else" ":" suite]

The starred_list expression is evaluated once; it should yield an iterable object. An iterator is created for that iterable. The first item provided by the iterator is then assigned to the target list using the standard rules for assignments (see 대입문), and the suite is executed. This repeats for each item provided by the iterator. When the iterator is exhausted, the suite in the else clause, if present, is executed, and the loop terminates.

첫 번째 스위트에서 실행되는 break 문은 else 절을 실행하지 않고 루프를 종료합니다. 첫 번째 스위트에서 실행되는 continue 문은 스위트의 나머지 부분을 건너뛰고 다음 항목으로 넘어가거나, 다음 항목이 없으면 else 절로 갑니다.

for-루프는 타깃 목록의 변수들에 대입합니다. for-루프의 스위트에서 이루어진 것들도 포함해서, 그 변수에 앞서 대입된 값들을 모두 덮어씁니다:

for i in range(10):
    print(i)
    i = 5             # this will not affect the for-loop
                      # because i will be overwritten with the next
                      # index in the range

Names in the target list are not deleted when the loop is finished, but if the sequence is empty, they will not have been assigned to at all by the loop. Hint: the built-in type range() represents immutable arithmetic sequences of integers. For instance, iterating range(3) successively yields 0, 1, and then 2.

버전 3.11에서 변경: Starred elements are now allowed in the expression list.

8.4. try 문

The try statement specifies exception handlers and/or cleanup code for a group of statements:

try_stmt  ::=  try1_stmt | try2_stmt | try3_stmt
try1_stmt ::=  "try" ":" suite
               ("except" [expression ["as" identifier]] ":" suite)+
               ["else" ":" suite]
               ["finally" ":" suite]
try2_stmt ::=  "try" ":" suite
               ("except" "*" expression ["as" identifier] ":" suite)+
               ["else" ":" suite]
               ["finally" ":" suite]
try3_stmt ::=  "try" ":" suite
               "finally" ":" suite

예외에 관한 추가의 정보는 예외 섹션에서 찾을 수 있고, 예외를 일으키기 위해 raise 문을 사용하는 것에 관한 정보는 raise 문 섹션에서 찾을 수 있습니다.

8.4.1. except clause

The except clause(s) specify one or more exception handlers. When no exception occurs in the try clause, no exception handler is executed. When an exception occurs in the try suite, a search for an exception handler is started. This search inspects the except clauses in turn until one is found that matches the exception. An expression-less except clause, if present, must be last; it matches any exception.

For an except clause with an expression, the expression must evaluate to an exception type or a tuple of exception types. The raised exception matches an except clause whose expression evaluates to the class or a non-virtual base class of the exception object, or to a tuple that contains such a class.

If no except clause matches the exception, the search for an exception handler continues in the surrounding code and on the invocation stack. [1]

If the evaluation of an expression in the header of an except clause raises an exception, the original search for a handler is canceled and a search starts for the new exception in the surrounding code and on the call stack (it is treated as if the entire try statement raised the exception).

When a matching except clause is found, the exception is assigned to the target specified after the as keyword in that except clause, if present, and the except clause’s suite is executed. All except clauses must have an executable block. When the end of this block is reached, execution continues normally after the entire try statement. (This means that if two nested handlers exist for the same exception, and the exception occurs in the try clause of the inner handler, the outer handler will not handle the exception.)

When an exception has been assigned using as target, it is cleared at the end of the except clause. This is as if

except E as N:
    foo

가 이렇게 변환되는 것과 같습니다

except E as N:
    try:
        foo
    finally:
        del N

This means the exception must be assigned to a different name to be able to refer to it after the except clause. Exceptions are cleared because with the traceback attached to them, they form a reference cycle with the stack frame, keeping all locals in that frame alive until the next garbage collection occurs.

Before an except clause’s suite is executed, the exception is stored in the sys module, where it can be accessed from within the body of the except clause by calling sys.exception(). When leaving an exception handler, the exception stored in the sys module is reset to its previous value:

>>> print(sys.exception())
None
>>> try:
...     raise TypeError
... except:
...     print(repr(sys.exception()))
...     try:
...          raise ValueError
...     except:
...         print(repr(sys.exception()))
...     print(repr(sys.exception()))
...
TypeError()
ValueError()
TypeError()
>>> print(sys.exception())
None

8.4.2. except* clause

The except* clause(s) are used for handling ExceptionGroups. The exception type for matching is interpreted as in the case of except, but in the case of exception groups we can have partial matches when the type matches some of the exceptions in the group. This means that multiple except* clauses can execute, each handling part of the exception group. Each clause executes at most once and handles an exception group of all matching exceptions. Each exception in the group is handled by at most one except* clause, the first that matches it.

>>> try:
...     raise ExceptionGroup("eg",
...         [ValueError(1), TypeError(2), OSError(3), OSError(4)])
... except* TypeError as e:
...     print(f'caught {type(e)} with nested {e.exceptions}')
... except* OSError as e:
...     print(f'caught {type(e)} with nested {e.exceptions}')
...
caught <class 'ExceptionGroup'> with nested (TypeError(2),)
caught <class 'ExceptionGroup'> with nested (OSError(3), OSError(4))
  + Exception Group Traceback (most recent call last):
  |   File "<stdin>", line 2, in <module>
  | ExceptionGroup: eg
  +-+---------------- 1 ----------------
    | ValueError: 1
    +------------------------------------

Any remaining exceptions that were not handled by any except* clause are re-raised at the end, along with all exceptions that were raised from within the except* clauses. If this list contains more than one exception to reraise, they are combined into an exception group.

If the raised exception is not an exception group and its type matches one of the except* clauses, it is caught and wrapped by an exception group with an empty message string.

>>> try:
...     raise BlockingIOError
... except* BlockingIOError as e:
...     print(repr(e))
...
ExceptionGroup('', (BlockingIOError()))

An except* clause must have a matching expression; it cannot be except*:. Furthermore, this expression cannot contain exception group types, because that would have ambiguous semantics.

It is not possible to mix except and except* in the same try. break, continue and return cannot appear in an except* clause.

8.4.3. else clause

생략 가능한 else 절은 제어 흐름이 try 스위트를 빠져나가고, 예외가 발생하지 않았고, return, continue 또는 break 문이 실행되지 않으면 실행됩니다. else 절에서 발생하는 예외는 앞에 나오는 except 절에서 처리되지 않습니다.

8.4.4. finally clause

If finally is present, it specifies a ‘cleanup’ handler. The try clause is executed, including any except and else clauses. If an exception occurs in any of the clauses and is not handled, the exception is temporarily saved. The finally clause is executed. If there is a saved exception it is re-raised at the end of the finally clause. If the finally clause raises another exception, the saved exception is set as the context of the new exception. If the finally clause executes a return, break or continue statement, the saved exception is discarded:

>>> def f():
...     try:
...         1/0
...     finally:
...         return 42
...
>>> f()
42

The exception information is not available to the program during execution of the finally clause.

When a return, break or continue statement is executed in the try suite of a try…finally statement, the finally clause is also executed ‘on the way out.’

The return value of a function is determined by the last return statement executed. Since the finally clause always executes, a return statement executed in the finally clause will always be the last one executed:

>>> def foo():
...     try:
...         return 'try'
...     finally:
...         return 'finally'
...
>>> foo()
'finally'

버전 3.8에서 변경: Prior to Python 3.8, a continue statement was illegal in the finally clause due to a problem with the implementation.

8.5. with 문

with 문은 블록의 실행을 컨텍스트 관리자 (with 문 컨텍스트 관리자 섹션을 보세요) 가 정의한 메서드들로 감싸는 데 사용됩니다. 이것은 흔한 try…except…finally 사용 패턴을 편리하게 재사용할 수 있도록 캡슐화할 수 있도록 합니다.

with_stmt          ::=  "with" ( "(" with_stmt_contents ","? ")" | with_stmt_contents ) ":" suite
with_stmt_contents ::=  with_item ("," with_item)*
with_item          ::=  expression ["as" target]

하나의 “item” 을 사용하는 with 문의 실행은 다음과 같이 진행됩니다:

The context expression (the expression given in the with_item) is evaluated to obtain a context manager.

The context manager’s __enter__() is loaded for later use.

The context manager’s __exit__() is loaded for later use.

The context manager’s __enter__() method is invoked.

If a target was included in the with statement, the return value from __enter__() is assigned to it.

참고

The with statement guarantees that if the __enter__() method returns without an error, then __exit__() will always be called. Thus, if an error occurs during the assignment to the target list, it will be treated the same as an error occurring within the suite would be. See step 7 below.

스위트가 실행됩니다.

The context manager’s __exit__() method is invoked. If an exception caused the suite to be exited, its type, value, and traceback are passed as arguments to __exit__(). Otherwise, three None arguments are supplied.

If the suite was exited due to an exception, and the return value from the __exit__() method was false, the exception is reraised. If the return value was true, the exception is suppressed, and execution continues with the statement following the with statement.

If the suite was exited for any reason other than an exception, the return value from __exit__() is ignored, and execution proceeds at the normal location for the kind of exit that was taken.

다음과 같은 코드는:

with EXPRESSION as TARGET:
    SUITE

의미상으로 다음과 동등합니다:

manager = (EXPRESSION)
enter = type(manager).__enter__
exit = type(manager).__exit__
value = enter(manager)

try:
    TARGET = value
    SUITE
except:
    if not exit(manager, *sys.exc_info()):
        raise
else:
    exit(manager, None, None, None)

하나 보다 많은 항목을 주면, 컨텍스트 관리자는 with 문이 중첩된 것처럼 진행합니다:

with A() as a, B() as b:
    SUITE

의미상으로 다음과 동등합니다:

with A() as a:
    with B() as b:
        SUITE

You can also write multi-item context managers in multiple lines if the items are surrounded by parentheses. For example:

with (
    A() as a,
    B() as b,
):
    SUITE

버전 3.1에서 변경: 다중 컨텍스트 표현식의 지원

버전 3.10에서 변경: Support for using grouping parentheses to break the statement in multiple lines.

더 보기

PEP 343 [https://peps.python.org/pep-0343/] - “with” 문

파이썬 with 문의 규격, 배경, 예.

8.6. The match statement

Added in version 3.10.

The match statement is used for pattern matching. Syntax:

match_stmt   ::=  'match' subject_expr ":" NEWLINE INDENT case_block+ DEDENT
subject_expr ::=  star_named_expression "," star_named_expressions?
                  | named_expression
case_block   ::=  'case' patterns [guard] ":" block

참고

This section uses single quotes to denote soft keywords.

Pattern matching takes a pattern as input (following case) and a subject value (following match). The pattern (which may contain subpatterns) is matched against the subject value. The outcomes are:

A match success or failure (also termed a pattern success or failure).

Possible binding of matched values to a name. The prerequisites for this are further discussed below.

The match and case keywords are soft keywords.

더 보기

PEP 634 [https://peps.python.org/pep-0634/] – Structural Pattern Matching: Specification

PEP 636 [https://peps.python.org/pep-0636/] – Structural Pattern Matching: Tutorial

8.6.1. Overview

Here’s an overview of the logical flow of a match statement:

The subject expression subject_expr is evaluated and a resulting subject value obtained. If the subject expression contains a comma, a tuple is constructed using the standard rules.

Each pattern in a case_block is attempted to match with the subject value. The specific rules for success or failure are described below. The match attempt can also bind some or all of the standalone names within the pattern. The precise pattern binding rules vary per pattern type and are specified below. Name bindings made during a successful pattern match outlive the executed block and can be used after the match statement.

참고

During failed pattern matches, some subpatterns may succeed. Do not rely on bindings being made for a failed match. Conversely, do not rely on variables remaining unchanged after a failed match. The exact behavior is dependent on implementation and may vary. This is an intentional decision made to allow different implementations to add optimizations.

If the pattern succeeds, the corresponding guard (if present) is evaluated. In this case all name bindings are guaranteed to have happened.

If the guard evaluates as true or is missing, the block inside case_block is executed.

Otherwise, the next case_block is attempted as described above.

If there are no further case blocks, the match statement is completed.

참고

Users should generally never rely on a pattern being evaluated. Depending on implementation, the interpreter may cache values or use other optimizations which skip repeated evaluations.

A sample match statement:

>>> flag = False
>>> match (100, 200):
...    case (100, 300):  # Mismatch: 200 != 300
...        print('Case 1')
...    case (100, 200) if flag:  # Successful match, but guard fails
...        print('Case 2')
...    case (100, y):  # Matches and binds y to 200
...        print(f'Case 3, y: {y}')
...    case _:  # Pattern not attempted
...        print('Case 4, I match anything!')
...
Case 3, y: 200

In this case, if flag is a guard. Read more about that in the next section.

8.6.2. Guards

guard ::=  "if" named_expression

A guard (which is part of the case) must succeed for code inside the case block to execute. It takes the form: if followed by an expression.

The logical flow of a case block with a guard follows:

Check that the pattern in the case block succeeded. If the pattern failed, the guard is not evaluated and the next case block is checked.

If the pattern succeeded, evaluate the guard.

If the guard condition evaluates as true, the case block is selected.

If the guard condition evaluates as false, the case block is not selected.

If the guard raises an exception during evaluation, the exception bubbles up.

Guards are allowed to have side effects as they are expressions. Guard evaluation must proceed from the first to the last case block, one at a time, skipping case blocks whose pattern(s) don’t all succeed. (I.e., guard evaluation must happen in order.) Guard evaluation must stop once a case block is selected.

8.6.3. Irrefutable Case Blocks

An irrefutable case block is a match-all case block. A match statement may have at most one irrefutable case block, and it must be last.

A case block is considered irrefutable if it has no guard and its pattern is irrefutable. A pattern is considered irrefutable if we can prove from its syntax alone that it will always succeed. Only the following patterns are irrefutable:

AS Patterns whose left-hand side is irrefutable

OR Patterns containing at least one irrefutable pattern

Capture Patterns

Wildcard Patterns

parenthesized irrefutable patterns

8.6.4. Patterns

참고

This section uses grammar notations beyond standard EBNF:

the notation SEP.RULE+ is shorthand for RULE (SEP RULE)*

the notation !RULE is shorthand for a negative lookahead assertion

The top-level syntax for patterns is:

patterns       ::=  open_sequence_pattern | pattern
pattern        ::=  as_pattern | or_pattern
closed_pattern ::=  | literal_pattern
                    | capture_pattern
                    | wildcard_pattern
                    | value_pattern
                    | group_pattern
                    | sequence_pattern
                    | mapping_pattern
                    | class_pattern

The descriptions below will include a description “in simple terms” of what a pattern does for illustration purposes (credits to Raymond Hettinger for a document that inspired most of the descriptions). Note that these descriptions are purely for illustration purposes and may not reflect the underlying implementation. Furthermore, they do not cover all valid forms.

8.6.4.1. OR Patterns

An OR pattern is two or more patterns separated by vertical bars |. Syntax:

or_pattern ::=  "|".closed_pattern+

Only the final subpattern may be irrefutable, and each subpattern must bind the same set of names to avoid ambiguity.

An OR pattern matches each of its subpatterns in turn to the subject value, until one succeeds. The OR pattern is then considered successful. Otherwise, if none of the subpatterns succeed, the OR pattern fails.

In simple terms, P1 | P2 | ... will try to match P1, if it fails it will try to match P2, succeeding immediately if any succeeds, failing otherwise.

8.6.4.2. AS Patterns

An AS pattern matches an OR pattern on the left of the as keyword against a subject. Syntax:

as_pattern ::=  or_pattern "as" capture_pattern

If the OR pattern fails, the AS pattern fails. Otherwise, the AS pattern binds the subject to the name on the right of the as keyword and succeeds. capture_pattern cannot be a _.

In simple terms P as NAME will match with P, and on success it will set NAME = <subject>.

8.6.4.3. Literal Patterns

A literal pattern corresponds to most literals in Python. Syntax:

literal_pattern ::=  signed_number
                     | signed_number "+" NUMBER
                     | signed_number "-" NUMBER
                     | strings
                     | "None"
                     | "True"
                     | "False"
signed_number   ::=  ["-"] NUMBER

The rule strings and the token NUMBER are defined in the standard Python grammar. Triple-quoted strings are supported. Raw strings and byte strings are supported. f-strings are not supported.

The forms signed_number '+' NUMBER and signed_number '-' NUMBER are for expressing complex numbers; they require a real number on the left and an imaginary number on the right. E.g. 3 + 4j.

In simple terms, LITERAL will succeed only if <subject> == LITERAL. For the singletons None, True and False, the is operator is used.

8.6.4.4. Capture Patterns

A capture pattern binds the subject value to a name. Syntax:

capture_pattern ::=  !'_' NAME

A single underscore _ is not a capture pattern (this is what !'_' expresses). It is instead treated as a wildcard_pattern.

In a given pattern, a given name can only be bound once. E.g. case x, x: ... is invalid while case [x] | x: ... is allowed.

Capture patterns always succeed. The binding follows scoping rules established by the assignment expression operator in PEP 572 [https://peps.python.org/pep-0572/]; the name becomes a local variable in the closest containing function scope unless there’s an applicable global or nonlocal statement.

In simple terms NAME will always succeed and it will set NAME = <subject>.

8.6.4.5. Wildcard Patterns

A wildcard pattern always succeeds (matches anything) and binds no name. Syntax:

wildcard_pattern ::=  '_'

_ is a soft keyword within any pattern, but only within patterns. It is an identifier, as usual, even within match subject expressions, guards, and case blocks.

In simple terms, _ will always succeed.

8.6.4.6. Value Patterns

A value pattern represents a named value in Python. Syntax:

value_pattern ::=  attr
attr          ::=  name_or_attr "." NAME
name_or_attr  ::=  attr | NAME

The dotted name in the pattern is looked up using standard Python name resolution rules. The pattern succeeds if the value found compares equal to the subject value (using the == equality operator).

In simple terms NAME1.NAME2 will succeed only if <subject> == NAME1.NAME2

참고

If the same value occurs multiple times in the same match statement, the interpreter may cache the first value found and reuse it rather than repeat the same lookup. This cache is strictly tied to a given execution of a given match statement.

8.6.4.7. Group Patterns

A group pattern allows users to add parentheses around patterns to emphasize the intended grouping. Otherwise, it has no additional syntax. Syntax:

group_pattern ::=  "(" pattern ")"

In simple terms (P) has the same effect as P.

8.6.4.8. Sequence Patterns

A sequence pattern contains several subpatterns to be matched against sequence elements. The syntax is similar to the unpacking of a list or tuple.

sequence_pattern       ::=  "[" [maybe_sequence_pattern] "]"
                            | "(" [open_sequence_pattern] ")"
open_sequence_pattern  ::=  maybe_star_pattern "," [maybe_sequence_pattern]
maybe_sequence_pattern ::=  ",".maybe_star_pattern+ ","?
maybe_star_pattern     ::=  star_pattern | pattern
star_pattern           ::=  "*" (capture_pattern | wildcard_pattern)

There is no difference if parentheses or square brackets are used for sequence patterns (i.e. (...) vs [...] ).

참고

A single pattern enclosed in parentheses without a trailing comma (e.g. (3 | 4)) is a group pattern. While a single pattern enclosed in square brackets (e.g. [3 | 4]) is still a sequence pattern.

At most one star subpattern may be in a sequence pattern. The star subpattern may occur in any position. If no star subpattern is present, the sequence pattern is a fixed-length sequence pattern; otherwise it is a variable-length sequence pattern.

The following is the logical flow for matching a sequence pattern against a subject value:

If the subject value is not a sequence [2], the sequence pattern fails.

If the subject value is an instance of str, bytes or bytearray the sequence pattern fails.

The subsequent steps depend on whether the sequence pattern is fixed or variable-length.

If the sequence pattern is fixed-length:

If the length of the subject sequence is not equal to the number of subpatterns, the sequence pattern fails

Subpatterns in the sequence pattern are matched to their corresponding items in the subject sequence from left to right. Matching stops as soon as a subpattern fails. If all subpatterns succeed in matching their corresponding item, the sequence pattern succeeds.

Otherwise, if the sequence pattern is variable-length:

If the length of the subject sequence is less than the number of non-star subpatterns, the sequence pattern fails.

The leading non-star subpatterns are matched to their corresponding items as for fixed-length sequences.

If the previous step succeeds, the star subpattern matches a list formed of the remaining subject items, excluding the remaining items corresponding to non-star subpatterns following the star subpattern.

Remaining non-star subpatterns are matched to their corresponding subject items, as for a fixed-length sequence.

참고

The length of the subject sequence is obtained via len() (i.e. via the __len__() protocol). This length may be cached by the interpreter in a similar manner as value patterns.

In simple terms [P1, P2, P3, … , P<N>] matches only if all the following happens:

check <subject> is a sequence

len(subject) == <N>

P1 matches <subject>[0] (note that this match can also bind names)

P2 matches <subject>[1] (note that this match can also bind names)

… and so on for the corresponding pattern/element.

8.6.4.9. Mapping Patterns

A mapping pattern contains one or more key-value patterns. The syntax is similar to the construction of a dictionary. Syntax:

mapping_pattern     ::=  "{" [items_pattern] "}"
items_pattern       ::=  ",".key_value_pattern+ ","?
key_value_pattern   ::=  (literal_pattern | value_pattern) ":" pattern
                         | double_star_pattern
double_star_pattern ::=  "**" capture_pattern

At most one double star pattern may be in a mapping pattern. The double star pattern must be the last subpattern in the mapping pattern.

Duplicate keys in mapping patterns are disallowed. Duplicate literal keys will raise a SyntaxError. Two keys that otherwise have the same value will raise a ValueError at runtime.

The following is the logical flow for matching a mapping pattern against a subject value:

If the subject value is not a mapping [3],the mapping pattern fails.

If every key given in the mapping pattern is present in the subject mapping, and the pattern for each key matches the corresponding item of the subject mapping, the mapping pattern succeeds.

If duplicate keys are detected in the mapping pattern, the pattern is considered invalid. A SyntaxError is raised for duplicate literal values; or a ValueError for named keys of the same value.

참고

Key-value pairs are matched using the two-argument form of the mapping subject’s get() method. Matched key-value pairs must already be present in the mapping, and not created on-the-fly via __missing__() or __getitem__().

In simple terms {KEY1: P1, KEY2: P2, ... } matches only if all the following happens:

check <subject> is a mapping

KEY1 in <subject>

P1 matches <subject>[KEY1]

… and so on for the corresponding KEY/pattern pair.

8.6.4.10. Class Patterns

A class pattern represents a class and its positional and keyword arguments (if any). Syntax:

class_pattern       ::=  name_or_attr "(" [pattern_arguments ","?] ")"
pattern_arguments   ::=  positional_patterns ["," keyword_patterns]
                         | keyword_patterns
positional_patterns ::=  ",".pattern+
keyword_patterns    ::=  ",".keyword_pattern+
keyword_pattern     ::=  NAME "=" pattern

The same keyword should not be repeated in class patterns.

The following is the logical flow for matching a class pattern against a subject value:

If name_or_attr is not an instance of the builtin type , raise TypeError.

If the subject value is not an instance of name_or_attr (tested via isinstance()), the class pattern fails.

If no pattern arguments are present, the pattern succeeds. Otherwise, the subsequent steps depend on whether keyword or positional argument patterns are present.

For a number of built-in types (specified below), a single positional subpattern is accepted which will match the entire subject; for these types keyword patterns also work as for other types.

If only keyword patterns are present, they are processed as follows, one by one:

I. The keyword is looked up as an attribute on the subject.

If this raises an exception other than AttributeError, the exception bubbles up.

If this raises AttributeError, the class pattern has failed.

Else, the subpattern associated with the keyword pattern is matched against the subject’s attribute value. If this fails, the class pattern fails; if this succeeds, the match proceeds to the next keyword.

II. If all keyword patterns succeed, the class pattern succeeds.

If any positional patterns are present, they are converted to keyword patterns using the __match_args__ attribute on the class name_or_attr before matching:

I. The equivalent of getattr(cls, "__match_args__", ()) is called.

If this raises an exception, the exception bubbles up.

If the returned value is not a tuple, the conversion fails and TypeError is raised.

If there are more positional patterns than len(cls.__match_args__), TypeError is raised.

Otherwise, positional pattern i is converted to a keyword pattern using __match_args__[i] as the keyword. __match_args__[i] must be a string; if not TypeError is raised.

If there are duplicate keywords, TypeError is raised.

더 보기

Customizing positional arguments in class pattern matching

II. Once all positional patterns have been converted to keyword patterns,

the match proceeds as if there were only keyword patterns.

For the following built-in types the handling of positional subpatterns is different:

bool

bytearray

bytes

dict

float

frozenset

int

list

set

str

tuple

These classes accept a single positional argument, and the pattern there is matched against the whole object rather than an attribute. For example int(0|1) matches the value 0, but not the value 0.0.

In simple terms CLS(P1, attr=P2) matches only if the following happens:

isinstance(<subject>, CLS)

convert P1 to a keyword pattern using CLS.__match_args__

For each keyword argument attr=P2:

hasattr(<subject>, "attr")

P2 matches <subject>.attr

… and so on for the corresponding keyword argument/pattern pair.

더 보기

PEP 634 [https://peps.python.org/pep-0634/] – Structural Pattern Matching: Specification

PEP 636 [https://peps.python.org/pep-0636/] – Structural Pattern Matching: Tutorial

8.7. 함수 정의

함수 정의는 사용자 정의 함수 객체 (표준형 계층 섹션을 보세요) 를 정의합니다:

funcdef                   ::=  [decorators] "def" funcname [type_params] "(" [parameter_list] ")"
                               ["->" expression] ":" suite
decorators                ::=  decorator+
decorator                 ::=  "@" assignment_expression NEWLINE
parameter_list            ::=  defparameter ("," defparameter)* "," "/" ["," [parameter_list_no_posonly]]
                                 | parameter_list_no_posonly
parameter_list_no_posonly ::=  defparameter ("," defparameter)* ["," [parameter_list_starargs]]
                               | parameter_list_starargs
parameter_list_starargs   ::=  "*" [star_parameter] ("," defparameter)* ["," ["**" parameter [","]]]
                               | "**" parameter [","]
parameter                 ::=  identifier [":" expression]
star_parameter            ::=  identifier [":" ["*"] expression]
defparameter              ::=  parameter ["=" expression]
funcname                  ::=  identifier

함수 정의는 실행할 수 있는 문장입니다. 실행하면 현재 지역 이름 공간의 함수 이름을 함수 객체 (함수의 실행 가능한 코드를 둘러싼 래퍼(wrapper)). 이 함수 객체는 현재의 이름 공간에 대한 참조를 포함하는데, 함수가 호출될 때 전역 이름 공간으로 사용됩니다.

함수 정의는 함수의 바디를 실행하지 않습니다. 함수가 호출될 때 실행됩니다. [4]

함수 정의는 하나나 그 이상의 데코레이터 표현식으로 감싸질 수 있습니다. 데코레이터 표현식은 함수가 정의될 때, 함수 정의를 포함하는 스코프에서 값을 구합니다. 그 결과는 콜러블이어야 하는데, 함수 객체만을 인자로 사용해서 호출됩니다. 반환 값이 함수 객체 대신 함수의 이름에 연결됩니다. 여러 개의 데코레이터는 중첩되는 방식으로 적용됩니다. 예를 들어, 다음과 같은 코드

@f1(arg)
@f2
def func(): pass

는 대략 다음과 동등합니다

def func(): pass
func = f1(arg)(f2(func))

원래의 함수가 임시로 이름 func 에 연결되지 않는다는 점만 다릅니다.

버전 3.9에서 변경: Functions may be decorated with any valid assignment_expression. Previously, the grammar was much more restrictive; see PEP 614 [https://peps.python.org/pep-0614/] for details.

A list of type parameters may be given in square brackets between the function’s name and the opening parenthesis for its parameter list. This indicates to static type checkers that the function is generic. At runtime, the type parameters can be retrieved from the function’s __type_params__ attribute. See Generic functions for more.

버전 3.12에서 변경: Type parameter lists are new in Python 3.12.

하나나 그 이상의 매개변수 들이 parameter = expression 형태를 가질 때, 함수가 “기본 매개변수 값”을 갖는다고 말합니다. 기본값이 있는 매개변수의 경우, 호출할 때 대응하는 인자 를 생략할 수 있고, 그럴 때 매개변수의 기본값이 적용됩니다. 만약 매개변수가 기본값을 가지면, “*” 까지 그 뒤를 따르는 모든 매개변수도 기본값을 가져야 합니다 — 이것은 문법 규칙에서 표현되지 않는 문법적 제약입니다.

Default parameter values are evaluated from left to right when the function definition is executed. This means that the expression is evaluated once, when the function is defined, and that the same “pre-computed” value is used for each call. This is especially important to understand when a default parameter value is a mutable object, such as a list or a dictionary: if the function modifies the object (e.g. by appending an item to a list), the default parameter value is in effect modified. This is generally not what was intended. A way around this is to use None as the default, and explicitly test for it in the body of the function, e.g.:

def whats_on_the_telly(penguin=None):
    if penguin is None:
        penguin = []
    penguin.append("property of the zoo")
    return penguin

Function call semantics are described in more detail in section 호출. A function call always assigns values to all parameters mentioned in the parameter list, either from positional arguments, from keyword arguments, or from default values. If the form “*identifier” is present, it is initialized to a tuple receiving any excess positional parameters, defaulting to the empty tuple. If the form “**identifier” is present, it is initialized to a new ordered mapping receiving any excess keyword arguments, defaulting to a new empty mapping of the same type. Parameters after “*” or “*identifier” are keyword-only parameters and may only be passed by keyword arguments. Parameters before “/” are positional-only parameters and may only be passed by positional arguments.

버전 3.8에서 변경: The / function parameter syntax may be used to indicate positional-only parameters. See PEP 570 [https://peps.python.org/pep-0570/] for details.

Parameters may have an annotation of the form “: expression” following the parameter name. Any parameter may have an annotation, even those of the form *identifier or **identifier. (As a special case, parameters of the form *identifier may have an annotation “: *expression”.) Functions may have “return” annotation of the form “-> expression” after the parameter list. These annotations can be any valid Python expression. The presence of annotations does not change the semantics of a function. See Annotations for more information on annotations.

버전 3.11에서 변경: Parameters of the form “*identifier” may have an annotation “: *expression”. See PEP 646 [https://peps.python.org/pep-0646/].

표현식에서 즉시 사용하기 위해, 이름 없는 함수(이름에 연결되지 않은 함수)를 만드는 것도 가능합니다. 이것은 람다 표현식을 사용하는데, 람다(Lambdas) 섹션에서 설명합니다. 람다 표현식은 단순화된 함수 정의를 위한 줄임 표현에 지나지 않는다는 것에 주의하세요; “def” 문장에서 정의된 함수는 람다 표현식으로 정의된 함수처럼 전달되거나 다른 이름에 대입될 수 있습니다. 여러 개의 문장을 실행하는 것과 어노테이션을 허락하기 때문에, “def” 형태가 사실 더 강력합니다.

프로그래머 유의 사항: 함수는 퍼스트 클래스(first-class) 객체다. 함수 정의 안에서 실행되는 “def” 문은 돌려주거나 전달할 수 있는 지역 함수를 정의합니다. 중첩된 함수에서 사용되는 자유 변수들은 그 def 를 포함하는 함수의 지역 변수들을 액세스할 수 있습니다. 더 자세한 내용은 이름과 연결(binding) 섹션을 보세요.

더 보기

PEP 3107 [https://peps.python.org/pep-3107/] - 함수 어노테이션

함수 어노테이션의 최초 규격.

PEP 484 [https://peps.python.org/pep-0484/] - 형 힌트

어노테이션에 대한 표준 의미 정의: 형 힌트.

PEP 526 [https://peps.python.org/pep-0526/] - 변수 어노테이션 문법

Ability to type hint variable declarations, including class variables and instance variables.

PEP 563 [https://peps.python.org/pep-0563/] - 어노테이션의 지연된 평가

즉시 평가하는 대신 실행시간에 어노테이션을 문자열 형식으로 보존하여 어노테이션 내에서의 전방 참조를 지원합니다.

PEP 318 [https://peps.python.org/pep-0318/] - Decorators for Functions and Methods

Function and method decorators were introduced. Class decorators were introduced in PEP 3129 [https://peps.python.org/pep-3129/].

8.8. 클래스 정의

클래스 정의는 클래스 객체(표준형 계층 섹션을 보세요)를 정의합니다:

classdef    ::=  [decorators] "class" classname [type_params] [inheritance] ":" suite
inheritance ::=  "(" [argument_list] ")"
classname   ::=  identifier

클래스 정의는 실행 가능한 문장입니다. 계승(inheritance) 목록은 보통 베이스 클래스들의 목록을 제공하는데 (더 고급 사용에 대해서는 메타 클래스 를 보세요), 목록의 각 항목은 값을 구할 때 서브 클래싱을 허락하는 클래스 객체가 되어야 합니다. 계승 목록이 없는 클래스는, 기본적으로, 베이스 클래스 object 를 계승합니다; 그래서

class Foo:
    pass

는 다음과 동등합니다

class Foo(object):
    pass

클래스의 스위트는 새로 만들어진 지역 이름 공간과 원래의 전역 이름 공간을 사용하는 새 실행 프레임 (이름과 연결(binding) 을 보세요)에서 실행됩니다. (보통, 스위트는 대부분 함수 정의들을 포함합니다.) 클래스의 스위트가 실행을 마치면, 실행 프레임은 파기하지만, 그것의 지역 이름 공간은 보존합니다. [5] 그런 다음, 계승 목록을 베이스 클래스들로, 보존된 지역 이름 공간을 어트리뷰트 딕셔너리로 사용해서 새 클래스 객체를 만듭니다. 클래스의 이름은 원래의 지역 이름 공간에서 이 클래스 객체와 연결됩니다.

The order in which attributes are defined in the class body is preserved in the new class’s __dict__. Note that this is reliable only right after the class is created and only for classes that were defined using the definition syntax.

클래스 생성은 메타 클래스 를 사용해서 심하게 커스터마이즈할 수 있습니다.

클래스 역시 함수를 데코레이팅할 때처럼 테코레이트할 수 있습니다,

@f1(arg)
@f2
class Foo: pass

는 대략 다음과 동등합니다

class Foo: pass
Foo = f1(arg)(f2(Foo))

데코레이터 표현식의 값을 구하는 규칙은 함수 데코레이터와 같습니다. 그런 다음 그 결과가 클래스 이름에 연결됩니다.

버전 3.9에서 변경: Classes may be decorated with any valid assignment_expression. Previously, the grammar was much more restrictive; see PEP 614 [https://peps.python.org/pep-0614/] for details.

A list of type parameters may be given in square brackets immediately after the class’s name. This indicates to static type checkers that the class is generic. At runtime, the type parameters can be retrieved from the class’s __type_params__ attribute. See Generic classes for more.

버전 3.12에서 변경: Type parameter lists are new in Python 3.12.

프로그래머 유의 사항: 클래스 정의에서 정의되는 변수들은 클래스 어트리뷰트입니다; 이것들은 인스턴스 간에 공유됩니다. 인스턴스 어트리뷰트는 메서드에서 self.name = value 로 설정될 수 있습니다. 클래스와 인스턴스 어트리뷰트 모두 “self.name” 표기법으로 액세스할 수 있고, 이런 식으로 액세스할 때 인스턴스 어트리뷰트는 같은 이름의 클래스 어트리뷰트를 가립니다. 클래스 어트리뷰트는 인스턴스 어트리뷰트의 기본값으로 사용될 수 있지만, 가변 값을 사용하는 것은 예상하지 않은 결과를 줄 수 있습니다. 디스크립터 를 다른 구현 상세를 갖는 인스턴스 변수를 만드는데 사용할 수 있습니다.

더 보기

PEP 3115 [https://peps.python.org/pep-3115/] - 파이썬 3000의 메타 클래스

메타 클래스 선언을 현재 문법으로 변경하고, 메타 클래스가 있는 클래스를 구성하는 방법의 의미를 변경하는 제안.

PEP 3129 [https://peps.python.org/pep-3129/] - 클래스 데코레이터

클래스 데코레이터를 추가하는 제안. 함수와 메서드 데코레이터는 PEP 318 [https://peps.python.org/pep-0318/]에서 도입되었습니다.

8.9. 코루틴

Added in version 3.5.

8.9.1. 코루틴 함수 정의

async_funcdef ::=  [decorators] "async" "def" funcname "(" [parameter_list] ")"
                   ["->" expression] ":" suite

Execution of Python coroutines can be suspended and resumed at many points (see coroutine). await expressions, async for and async with can only be used in the body of a coroutine function.

async def 문법으로 정의된 함수는 항상 코루틴 함수인데, await 나 async 키워드를 포함하지 않는 경우도 그렇습니다.

코루틴 함수의 바디 안에서 yield from 표현식을 사용하는 것은 SyntaxError 입니다.

코루틴 함수의 예:

async def func(param1, param2):
    do_stuff()
    await some_coroutine()

버전 3.7에서 변경: await and async are now keywords; previously they were only treated as such inside the body of a coroutine function.

8.9.2. async for 문

async_for_stmt ::=  "async" for_stmt

비동기 이터러블 은 비동기 이터레이터 를 직접 반환하는 __aiter__ 메서드를 제공하고, 비동기 이터레이터는 자신의 __anext__ 메서드에서 비동기 코드를 호출할 수 있습니다.

async for 문은 비동기 이터러블에 대한 편리한 이터레이션을 허락합니다.

다음과 같은 코드는:

async for TARGET in ITER:
    SUITE
else:
    SUITE2

의미상으로 다음과 동등합니다:

iter = (ITER)
iter = type(iter).__aiter__(iter)
running = True

while running:
    try:
        TARGET = await type(iter).__anext__(iter)
    except StopAsyncIteration:
        running = False
    else:
        SUITE
else:
    SUITE2

See also __aiter__() and __anext__() for details.

코루틴 함수의 바디 밖에서 async for 문을 사용하는 것은 SyntaxError 입니다.

8.9.3. async with 문

async_with_stmt ::=  "async" with_stmt

비동기 컨텍스트 관리자 는 enter 와 exit 메서드에서 실행을 일시 중지할 수 있는 컨텍스트 관리자 입니다.

다음과 같은 코드는:

async with EXPRESSION as TARGET:
    SUITE

의미상으로 다음과 동등합니다:

manager = (EXPRESSION)
aenter = type(manager).__aenter__
aexit = type(manager).__aexit__
value = await aenter(manager)
hit_except = False

try:
    TARGET = value
    SUITE
except:
    hit_except = True
    if not await aexit(manager, *sys.exc_info()):
        raise
finally:
    if not hit_except:
        await aexit(manager, None, None, None)

See also __aenter__() and __aexit__() for details.

코루틴 함수의 바디 밖에서 async with 문을 사용하는 것은 SyntaxError 입니다.

더 보기

PEP 492 [https://peps.python.org/pep-0492/] - async 와 await 문법을 사용하는 코루틴

코루틴을 파이썬에서 적절한 독립적인 개념으로 만들고, 문법 지원을 추가한 제안.

8.10. Type parameter lists

Added in version 3.12.

버전 3.13에서 변경: Support for default values was added (see PEP 696 [https://peps.python.org/pep-0696/]).

type_params  ::=  "[" type_param ("," type_param)* "]"
type_param   ::=  typevar | typevartuple | paramspec
typevar      ::=  identifier (":" expression)? ("=" expression)?
typevartuple ::=  "*" identifier ("=" expression)?
paramspec    ::=  "**" identifier ("=" expression)?

Functions (including coroutines), classes and type aliases may contain a type parameter list:

def max[T](args: list[T]) -> T:
    ...

async def amax[T](args: list[T]) -> T:
    ...

class Bag[T]:
    def __iter__(self) -> Iterator[T]:
        ...

    def add(self, arg: T) -> None:
        ...

type ListOrSet[T] = list[T] | set[T]

Semantically, this indicates that the function, class, or type alias is generic over a type variable. This information is primarily used by static type checkers, and at runtime, generic objects behave much like their non-generic counterparts.

Type parameters are declared in square brackets ([]) immediately after the name of the function, class, or type alias. The type parameters are accessible within the scope of the generic object, but not elsewhere. Thus, after a declaration def func[T](): pass, the name T is not available in the module scope. Below, the semantics of generic objects are described with more precision. The scope of type parameters is modeled with a special function (technically, an annotation scope) that wraps the creation of the generic object.

Generic functions, classes, and type aliases have a __type_params__ attribute listing their type parameters.

Type parameters come in three kinds:

typing.TypeVar, introduced by a plain name (e.g., T). Semantically, this represents a single type to a type checker.

typing.TypeVarTuple, introduced by a name prefixed with a single asterisk (e.g., *Ts). Semantically, this stands for a tuple of any number of types.

typing.ParamSpec, introduced by a name prefixed with two asterisks (e.g., **P). Semantically, this stands for the parameters of a callable.

typing.TypeVar declarations can define bounds and constraints with a colon (:) followed by an expression. A single expression after the colon indicates a bound (e.g. T: int). Semantically, this means that the typing.TypeVar can only represent types that are a subtype of this bound. A parenthesized tuple of expressions after the colon indicates a set of constraints (e.g. T: (str, bytes)). Each member of the tuple should be a type (again, this is not enforced at runtime). Constrained type variables can only take on one of the types in the list of constraints.

For typing.TypeVars declared using the type parameter list syntax, the bound and constraints are not evaluated when the generic object is created, but only when the value is explicitly accessed through the attributes __bound__ and __constraints__. To accomplish this, the bounds or constraints are evaluated in a separate annotation scope.

typing.TypeVarTuples and typing.ParamSpecs cannot have bounds or constraints.

All three flavors of type parameters can also have a default value, which is used when the type parameter is not explicitly provided. This is added by appending a single equals sign (=) followed by an expression. Like the bounds and constraints of type variables, the default value is not evaluated when the object is created, but only when the type parameter’s __default__ attribute is accessed. To this end, the default value is evaluated in a separate annotation scope. If no default value is specified for a type parameter, the __default__ attribute is set to the special sentinel object typing.NoDefault.

The following example indicates the full set of allowed type parameter declarations:

def overly_generic[
   SimpleTypeVar,
   TypeVarWithDefault = int,
   TypeVarWithBound: int,
   TypeVarWithConstraints: (str, bytes),
   *SimpleTypeVarTuple = (int, float),
   **SimpleParamSpec = (str, bytearray),
](
   a: SimpleTypeVar,
   b: TypeVarWithDefault,
   c: TypeVarWithBound,
   d: Callable[SimpleParamSpec, TypeVarWithConstraints],
   *e: SimpleTypeVarTuple,
): ...

8.10.1. Generic functions

Generic functions are declared as follows:

def func[T](arg: T): ...

This syntax is equivalent to:

annotation-def TYPE_PARAMS_OF_func():
    T = typing.TypeVar("T")
    def func(arg: T): ...
    func.__type_params__ = (T,)
    return func
func = TYPE_PARAMS_OF_func()

Here annotation-def indicates an annotation scope, which is not actually bound to any name at runtime. (One other liberty is taken in the translation: the syntax does not go through attribute access on the typing module, but creates an instance of typing.TypeVar directly.)

The annotations of generic functions are evaluated within the annotation scope used for declaring the type parameters, but the function’s defaults and decorators are not.

The following example illustrates the scoping rules for these cases, as well as for additional flavors of type parameters:

@decorator
def func[T: int, *Ts, **P](*args: *Ts, arg: Callable[P, T] = some_default):
    ...

Except for the lazy evaluation of the TypeVar bound, this is equivalent to:

DEFAULT_OF_arg = some_default

annotation-def TYPE_PARAMS_OF_func():

    annotation-def BOUND_OF_T():
        return int
    # In reality, BOUND_OF_T() is evaluated only on demand.
    T = typing.TypeVar("T", bound=BOUND_OF_T())

    Ts = typing.TypeVarTuple("Ts")
    P = typing.ParamSpec("P")

    def func(*args: *Ts, arg: Callable[P, T] = DEFAULT_OF_arg):
        ...

    func.__type_params__ = (T, Ts, P)
    return func
func = decorator(TYPE_PARAMS_OF_func())

The capitalized names like DEFAULT_OF_arg are not actually bound at runtime.

8.10.2. Generic classes

Generic classes are declared as follows:

class Bag[T]: ...

This syntax is equivalent to:

annotation-def TYPE_PARAMS_OF_Bag():
    T = typing.TypeVar("T")
    class Bag(typing.Generic[T]):
        __type_params__ = (T,)
        ...
    return Bag
Bag = TYPE_PARAMS_OF_Bag()

Here again annotation-def (not a real keyword) indicates an annotation scope, and the name TYPE_PARAMS_OF_Bag is not actually bound at runtime.

Generic classes implicitly inherit from typing.Generic. The base classes and keyword arguments of generic classes are evaluated within the type scope for the type parameters, and decorators are evaluated outside that scope. This is illustrated by this example:

@decorator
class Bag(Base[T], arg=T): ...

This is equivalent to:

annotation-def TYPE_PARAMS_OF_Bag():
    T = typing.TypeVar("T")
    class Bag(Base[T], typing.Generic[T], arg=T):
        __type_params__ = (T,)
        ...
    return Bag
Bag = decorator(TYPE_PARAMS_OF_Bag())

8.10.3. Generic type aliases

The type statement can also be used to create a generic type alias:

type ListOrSet[T] = list[T] | set[T]

Except for the lazy evaluation of the value, this is equivalent to:

annotation-def TYPE_PARAMS_OF_ListOrSet():
    T = typing.TypeVar("T")

    annotation-def VALUE_OF_ListOrSet():
        return list[T] | set[T]
    # In reality, the value is lazily evaluated
    return typing.TypeAliasType("ListOrSet", VALUE_OF_ListOrSet(), type_params=(T,))
ListOrSet = TYPE_PARAMS_OF_ListOrSet()

Here, annotation-def (not a real keyword) indicates an annotation scope. The capitalized names like TYPE_PARAMS_OF_ListOrSet are not actually bound at runtime.

8.11. Annotations

버전 3.14에서 변경: Annotations are now lazily evaluated by default.

Variables and function parameters may carry annotations, created by adding a colon after the name, followed by an expression:

x: annotation = 1
def f(param: annotation): ...

Functions may also carry a return annotation following an arrow:

def f() -> annotation: ...

Annotations are conventionally used for type hints, but this is not enforced by the language, and in general annotations may contain arbitrary expressions. The presence of annotations does not change the runtime semantics of the code, except if some mechanism is used that introspects and uses the annotations (such as dataclasses or functools.singledispatch()).

By default, annotations are lazily evaluated in a annotation scope. This means that they are not evaluated when the code containing the annotation is evaluated. Instead, the interpreter saves information that can be used to evaluate the annotation later if requested. The annotationlib module provides tools for evaluating annotations.

If the future statement from __future__ import annotations is present, all annotations are instead stored as strings:

>>> from __future__ import annotations
>>> def f(param: annotation): ...
>>> f.__annotations__
{'param': 'annotation'}

각주

[1]

다른 예외를 일으키는 finally 절이 있지 않은 한 예외는 호출 스택으로 퍼집니다. 그 새 예외는 예전의 것을 잃어버리게 만듭니다.

[2]

In pattern matching, a sequence is defined as one of the following:

a class that inherits from collections.abc.Sequence

a Python class that has been registered as collections.abc.Sequence

a builtin class that has its (CPython) Py_TPFLAGS_SEQUENCE bit set

a class that inherits from any of the above

The following standard library classes are sequences:

array.array

collections.deque

list

memoryview

range

tuple

참고

Subject values of type str, bytes, and bytearray do not match sequence patterns.

[3]

In pattern matching, a mapping is defined as one of the following:

a class that inherits from collections.abc.Mapping

a Python class that has been registered as collections.abc.Mapping

a builtin class that has its (CPython) Py_TPFLAGS_MAPPING bit set

a class that inherits from any of the above

The standard library classes dict and types.MappingProxyType are mappings.

[4]

A string literal appearing as the first statement in the function body is transformed into the function’s __doc__ attribute and therefore the function’s docstring.

[5]

A string literal appearing as the first statement in the class body is transformed into the namespace’s __doc__ item and therefore the class’s docstring.

9. 최상위 요소들

파이썬 인터프리터는 여러 가지 출처로부터 입력을 얻을 수 있습니다: 표준 입력이나 프로그램 인자로 전달된 스크립트, 대화형으로 입력된 것, 모듈 소스 파일 등등. 이 장은 이 경우들에 사용되는 문법을 제공합니다.

9.1. 완전한 파이썬 프로그램

언어 규격이 어떤 식으로 언어 인터프리터가 실행되는지를 미리 규정할 필요는 없지만, 완전한 파이썬 프로그램이라는 개념을 갖는 것은 쓸모가 있습니다. 완전한 파이썬 프로그램은 최소한으로 초기화된 환경에서 실행됩니다: 모든 내장과 표준 모듈이 제공되지만, sys (각종 시스템 서비스들)와 builtins (내장 함수들, 예외들, None)과 __main__ 이외의 어느 것도 초기화되지 않았습니다. 마지막 것은 완전한 프로그램의 실행을 위한 지역과 전역 이름 공간을 제공하는 데 사용됩니다.

완전한 파이썬 프로그램의 문법은 다음 섹션에서 설명되는 파일 입력의 경우입니다.

인터프리터는 대화형으로 실행될 수도 있습니다; 이 경우, 완전한 프로그램을 읽어서 실행하지 않고, 한 번에 한 문장 (복합문도 가능하다) 씩 읽어서 실행합니다. 초기 환경은 완전한 프로그램과 같습니다; 각 문장은 __main__ 의 이름 공간에서 실행됩니다.

완전한 프로그램은 세 가지 형태로 인터프리터에게 전달될 수 있습니다: -c string 명령행 옵션으로, 첫 번째 명령행 인자로 전달된 파일로, 표준 입력으로. 파일이나 표준입력이 tty 장치면, 인터프리터는 대화형 모드로 돌입합니다; 그렇지 않으면 그 파일을 완전한 프로그램으로 실행합니다.

9.2. 파일 입력

비대화형 파일로부터 읽힌 모든 입력은 같은 형태를 취합니다:

file_input ::=  (NEWLINE | statement)*

이 문법은 다음과 같은 상황에서 사용됩니다:

(파일이나 문자열로부터 온) 완전한 파이썬 프로그램을 파싱할 때;

모듈을 파싱할 때;

exec() 함수로 전달된 문자열을 파싱할 때;

9.3. 대화형 입력

대화형 모드에서의 입력은 다음과 같은 문법 규칙을 사용합니다:

interactive_input ::=  [stmt_list] NEWLINE | compound_stmt NEWLINE

(최상위) 복합문은 대화형 모드에서 빈 줄을 붙여줘야 함에 유념해야 합니다; 파서가 입력의 끝을 감지하는 데 필요합니다.

9.4. 표현식 입력

표현식 입력을 위해 eval() 이 사용됩니다. 앞에 오는 공백을 무시합니다. eval() 의 문자열 인자는 다음과 같은 형식을 취해야 합니다:

eval_input ::=  expression_list NEWLINE*

10. 전체 문법 규격

이것은 CPython 구문 분석기를 생성하는 데 사용되는 문법에서 직접 파생된, 전체 파이썬 문법 규칙입니다 (Grammar/python.gram [https://github.com/python/cpython/tree/main/Grammar/python.gram]을 참조하십시오). 이 버전은 코드 생성과 에러 복구와 관련된 세부 정보를 생략합니다.

The notation is a mixture of EBNF [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form] and PEG [https://en.wikipedia.org/wiki/Parsing_expression_grammar]. In particular, & followed by a symbol, token or parenthesized group indicates a positive lookahead (i.e., is required to match but not consumed), while ! indicates a negative lookahead (i.e., is required not to match). We use the | separator to mean PEG’s “ordered choice” (written as / in traditional PEG grammars). See PEP 617 [https://peps.python.org/pep-0617/] for more details on the grammar’s syntax.

# PEG grammar for Python

# ========================= START OF THE GRAMMAR =========================

# General grammatical elements and rules:
#
# * Strings with double quotes (") denote SOFT KEYWORDS
# * Strings with single quotes (') denote KEYWORDS
# * Upper case names (NAME) denote tokens in the Grammar/Tokens file
# * Rule names starting with "invalid_" are used for specialized syntax errors
#     - These rules are NOT used in the first pass of the parser.
#     - Only if the first pass fails to parse, a second pass including the invalid
#       rules will be executed.
#     - If the parser fails in the second phase with a generic syntax error, the
#       location of the generic failure of the first pass will be used (this avoids
#       reporting incorrect locations due to the invalid rules).
#     - The order of the alternatives involving invalid rules matter
#       (like any rule in PEG).
#
# Grammar Syntax (see PEP 617 for more information):
#
# rule_name: expression
#   Optionally, a type can be included right after the rule name, which
#   specifies the return type of the C or Python function corresponding to the
#   rule:
# rule_name[return_type]: expression
#   If the return type is omitted, then a void * is returned in C and an Any in
#   Python.
# e1 e2
#   Match e1, then match e2.
# e1 | e2
#   Match e1 or e2.
#   The first alternative can also appear on the line after the rule name for
#   formatting purposes. In that case, a | must be used before the first
#   alternative, like so:
#       rule_name[return_type]:
#            | first_alt
#            | second_alt
# ( e )
#   Match e (allows also to use other operators in the group like '(e)*')
# [ e ] or e?
#   Optionally match e.
# e*
#   Match zero or more occurrences of e.
# e+
#   Match one or more occurrences of e.
# s.e+
#   Match one or more occurrences of e, separated by s. The generated parse tree
#   does not include the separator. This is otherwise identical to (e (s e)*).
# &e
#   Succeed if e can be parsed, without consuming any input.
# !e
#   Fail if e can be parsed, without consuming any input.
# ~
#   Commit to the current alternative, even if it fails to parse.
# &&e
#   Eager parse e. The parser will not backtrack and will immediately
#   fail with SyntaxError if e cannot be parsed.
#

# STARTING RULES
# ==============

file: [statements] ENDMARKER
interactive: statement_newline
eval: expressions NEWLINE* ENDMARKER
func_type: '(' [type_expressions] ')' '->' expression NEWLINE* ENDMARKER

# GENERAL STATEMENTS
# ==================

statements: statement+

statement: compound_stmt  | simple_stmts

statement_newline:
    | compound_stmt NEWLINE
    | simple_stmts
    | NEWLINE
    | ENDMARKER

simple_stmts:
    | simple_stmt !';' NEWLINE  # Not needed, there for speedup
    | ';'.simple_stmt+ [';'] NEWLINE

# NOTE: assignment MUST precede expression, else parsing a simple assignment
# will throw a SyntaxError.
simple_stmt:
    | assignment
    | type_alias
    | star_expressions
    | return_stmt
    | import_stmt
    | raise_stmt
    | 'pass'
    | del_stmt
    | yield_stmt
    | assert_stmt
    | 'break'
    | 'continue'
    | global_stmt
    | nonlocal_stmt

compound_stmt:
    | function_def
    | if_stmt
    | class_def
    | with_stmt
    | for_stmt
    | try_stmt
    | while_stmt
    | match_stmt

# SIMPLE STATEMENTS
# =================

# NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield'
assignment:
    | NAME ':' expression ['=' annotated_rhs ]
    | ('(' single_target ')'
         | single_subscript_attribute_target) ':' expression ['=' annotated_rhs ]
    | (star_targets '=' )+ annotated_rhs !'=' [TYPE_COMMENT]
    | single_target augassign ~ annotated_rhs

annotated_rhs: yield_expr | star_expressions

augassign:
    | '+='
    | '-='
    | '*='
    | '@='
    | '/='
    | '%='
    | '&='
    | '|='
    | '^='
    | '<<='
    | '>>='
    | '**='
    | '//='

return_stmt:
    | 'return' [star_expressions]

raise_stmt:
    | 'raise' expression ['from' expression ]
    | 'raise'

global_stmt: 'global' ','.NAME+

nonlocal_stmt: 'nonlocal' ','.NAME+

del_stmt:
    | 'del' del_targets &(';' | NEWLINE)

yield_stmt: yield_expr

assert_stmt: 'assert' expression [',' expression ]

import_stmt:
    | import_name
    | import_from

# Import statements
# -----------------

import_name: 'import' dotted_as_names
# note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
import_from:
    | 'from' ('.' | '...')* dotted_name 'import' import_from_targets
    | 'from' ('.' | '...')+ 'import' import_from_targets
import_from_targets:
    | '(' import_from_as_names [','] ')'
    | import_from_as_names !','
    | '*'
import_from_as_names:
    | ','.import_from_as_name+
import_from_as_name:
    | NAME ['as' NAME ]
dotted_as_names:
    | ','.dotted_as_name+
dotted_as_name:
    | dotted_name ['as' NAME ]
dotted_name:
    | dotted_name '.' NAME
    | NAME

# COMPOUND STATEMENTS
# ===================

# Common elements
# ---------------

block:
    | NEWLINE INDENT statements DEDENT
    | simple_stmts

decorators: ('@' named_expression NEWLINE )+

# Class definitions
# -----------------

class_def:
    | decorators class_def_raw
    | class_def_raw

class_def_raw:
    | 'class' NAME [type_params] ['(' [arguments] ')' ] ':' block

# Function definitions
# --------------------

function_def:
    | decorators function_def_raw
    | function_def_raw

function_def_raw:
    | 'def' NAME [type_params] '(' [params] ')' ['->' expression ] ':' [func_type_comment] block
    | 'async' 'def' NAME [type_params] '(' [params] ')' ['->' expression ] ':' [func_type_comment] block

# Function parameters
# -------------------

params:
    | parameters

parameters:
    | slash_no_default param_no_default* param_with_default* [star_etc]
    | slash_with_default param_with_default* [star_etc]
    | param_no_default+ param_with_default* [star_etc]
    | param_with_default+ [star_etc]
    | star_etc

# Some duplication here because we can't write (',' | &')'),
# which is because we don't support empty alternatives (yet).

slash_no_default:
    | param_no_default+ '/' ','
    | param_no_default+ '/' &')'
slash_with_default:
    | param_no_default* param_with_default+ '/' ','
    | param_no_default* param_with_default+ '/' &')'

star_etc:
    | '*' param_no_default param_maybe_default* [kwds]
    | '*' param_no_default_star_annotation param_maybe_default* [kwds]
    | '*' ',' param_maybe_default+ [kwds]
    | kwds

kwds:
    | '**' param_no_default

# One parameter.  This *includes* a following comma and type comment.
#
# There are three styles:
# - No default
# - With default
# - Maybe with default
#
# There are two alternative forms of each, to deal with type comments:
# - Ends in a comma followed by an optional type comment
# - No comma, optional type comment, must be followed by close paren
# The latter form is for a final parameter without trailing comma.
#

param_no_default:
    | param ',' TYPE_COMMENT?
    | param TYPE_COMMENT? &')'
param_no_default_star_annotation:
    | param_star_annotation ',' TYPE_COMMENT?
    | param_star_annotation TYPE_COMMENT? &')'
param_with_default:
    | param default ',' TYPE_COMMENT?
    | param default TYPE_COMMENT? &')'
param_maybe_default:
    | param default? ',' TYPE_COMMENT?
    | param default? TYPE_COMMENT? &')'
param: NAME annotation?
param_star_annotation: NAME star_annotation
annotation: ':' expression
star_annotation: ':' star_expression
default: '=' expression  | invalid_default

# If statement
# ------------

if_stmt:
    | 'if' named_expression ':' block elif_stmt
    | 'if' named_expression ':' block [else_block]
elif_stmt:
    | 'elif' named_expression ':' block elif_stmt
    | 'elif' named_expression ':' block [else_block]
else_block:
    | 'else' ':' block

# While statement
# ---------------

while_stmt:
    | 'while' named_expression ':' block [else_block]

# For statement
# -------------

for_stmt:
    | 'for' star_targets 'in' ~ star_expressions ':' [TYPE_COMMENT] block [else_block]
    | 'async' 'for' star_targets 'in' ~ star_expressions ':' [TYPE_COMMENT] block [else_block]

# With statement
# --------------

with_stmt:
    | 'with' '(' ','.with_item+ ','? ')' ':' [TYPE_COMMENT] block
    | 'with' ','.with_item+ ':' [TYPE_COMMENT] block
    | 'async' 'with' '(' ','.with_item+ ','? ')' ':' block
    | 'async' 'with' ','.with_item+ ':' [TYPE_COMMENT] block

with_item:
    | expression 'as' star_target &(',' | ')' | ':')
    | expression

# Try statement
# -------------

try_stmt:
    | 'try' ':' block finally_block
    | 'try' ':' block except_block+ [else_block] [finally_block]
    | 'try' ':' block except_star_block+ [else_block] [finally_block]

# Except statement
# ----------------

except_block:
    | 'except' expression ['as' NAME ] ':' block
    | 'except' ':' block
except_star_block:
    | 'except' '*' expression ['as' NAME ] ':' block
finally_block:
    | 'finally' ':' block

# Match statement
# ---------------

match_stmt:
    | "match" subject_expr ':' NEWLINE INDENT case_block+ DEDENT

subject_expr:
    | star_named_expression ',' star_named_expressions?
    | named_expression

case_block:
    | "case" patterns guard? ':' block

guard: 'if' named_expression

patterns:
    | open_sequence_pattern
    | pattern

pattern:
    | as_pattern
    | or_pattern

as_pattern:
    | or_pattern 'as' pattern_capture_target

or_pattern:
    | '|'.closed_pattern+

closed_pattern:
    | literal_pattern
    | capture_pattern
    | wildcard_pattern
    | value_pattern
    | group_pattern
    | sequence_pattern
    | mapping_pattern
    | class_pattern

# Literal patterns are used for equality and identity constraints
literal_pattern:
    | signed_number !('+' | '-')
    | complex_number
    | strings
    | 'None'
    | 'True'
    | 'False'

# Literal expressions are used to restrict permitted mapping pattern keys
literal_expr:
    | signed_number !('+' | '-')
    | complex_number
    | strings
    | 'None'
    | 'True'
    | 'False'

complex_number:
    | signed_real_number '+' imaginary_number
    | signed_real_number '-' imaginary_number

signed_number:
    | NUMBER
    | '-' NUMBER

signed_real_number:
    | real_number
    | '-' real_number

real_number:
    | NUMBER

imaginary_number:
    | NUMBER

capture_pattern:
    | pattern_capture_target

pattern_capture_target:
    | !"_" NAME !('.' | '(' | '=')

wildcard_pattern:
    | "_"

value_pattern:
    | attr !('.' | '(' | '=')

attr:
    | name_or_attr '.' NAME

name_or_attr:
    | attr
    | NAME

group_pattern:
    | '(' pattern ')'

sequence_pattern:
    | '[' maybe_sequence_pattern? ']'
    | '(' open_sequence_pattern? ')'

open_sequence_pattern:
    | maybe_star_pattern ',' maybe_sequence_pattern?

maybe_sequence_pattern:
    | ','.maybe_star_pattern+ ','?

maybe_star_pattern:
    | star_pattern
    | pattern

star_pattern:
    | '*' pattern_capture_target
    | '*' wildcard_pattern

mapping_pattern:
    | '{' '}'
    | '{' double_star_pattern ','? '}'
    | '{' items_pattern ',' double_star_pattern ','? '}'
    | '{' items_pattern ','? '}'

items_pattern:
    | ','.key_value_pattern+

key_value_pattern:
    | (literal_expr | attr) ':' pattern

double_star_pattern:
    | '**' pattern_capture_target

class_pattern:
    | name_or_attr '(' ')'
    | name_or_attr '(' positional_patterns ','? ')'
    | name_or_attr '(' keyword_patterns ','? ')'
    | name_or_attr '(' positional_patterns ',' keyword_patterns ','? ')'

positional_patterns:
    | ','.pattern+

keyword_patterns:
    | ','.keyword_pattern+

keyword_pattern:
    | NAME '=' pattern

# Type statement
# ---------------

type_alias:
    | "type" NAME [type_params] '=' expression

# Type parameter declaration
# --------------------------

type_params:
    | invalid_type_params
    | '[' type_param_seq ']'

type_param_seq: ','.type_param+ [',']

type_param:
    | NAME [type_param_bound] [type_param_default]
    | '*' NAME [type_param_starred_default]
    | '**' NAME [type_param_default]

type_param_bound: ':' expression
type_param_default: '=' expression
type_param_starred_default: '=' star_expression

# EXPRESSIONS
# -----------

expressions:
    | expression (',' expression )+ [',']
    | expression ','
    | expression

expression:
    | disjunction 'if' disjunction 'else' expression
    | disjunction
    | lambdef

yield_expr:
    | 'yield' 'from' expression
    | 'yield' [star_expressions]

star_expressions:
    | star_expression (',' star_expression )+ [',']
    | star_expression ','
    | star_expression

star_expression:
    | '*' bitwise_or
    | expression

star_named_expressions: ','.star_named_expression+ [',']

star_named_expression:
    | '*' bitwise_or
    | named_expression

assignment_expression:
    | NAME ':=' ~ expression

named_expression:
    | assignment_expression
    | expression !':='

disjunction:
    | conjunction ('or' conjunction )+
    | conjunction

conjunction:
    | inversion ('and' inversion )+
    | inversion

inversion:
    | 'not' inversion
    | comparison

# Comparison operators
# --------------------

comparison:
    | bitwise_or compare_op_bitwise_or_pair+
    | bitwise_or

compare_op_bitwise_or_pair:
    | eq_bitwise_or
    | noteq_bitwise_or
    | lte_bitwise_or
    | lt_bitwise_or
    | gte_bitwise_or
    | gt_bitwise_or
    | notin_bitwise_or
    | in_bitwise_or
    | isnot_bitwise_or
    | is_bitwise_or

eq_bitwise_or: '==' bitwise_or
noteq_bitwise_or:
    | ('!=' ) bitwise_or
lte_bitwise_or: '<=' bitwise_or
lt_bitwise_or: '<' bitwise_or
gte_bitwise_or: '>=' bitwise_or
gt_bitwise_or: '>' bitwise_or
notin_bitwise_or: 'not' 'in' bitwise_or
in_bitwise_or: 'in' bitwise_or
isnot_bitwise_or: 'is' 'not' bitwise_or
is_bitwise_or: 'is' bitwise_or

# Bitwise operators
# -----------------

bitwise_or:
    | bitwise_or '|' bitwise_xor
    | bitwise_xor

bitwise_xor:
    | bitwise_xor '^' bitwise_and
    | bitwise_and

bitwise_and:
    | bitwise_and '&' shift_expr
    | shift_expr

shift_expr:
    | shift_expr '<<' sum
    | shift_expr '>>' sum
    | sum

# Arithmetic operators
# --------------------

sum:
    | sum '+' term
    | sum '-' term
    | term

term:
    | term '*' factor
    | term '/' factor
    | term '//' factor
    | term '%' factor
    | term '@' factor
    | factor

factor:
    | '+' factor
    | '-' factor
    | '~' factor
    | power

power:
    | await_primary '**' factor
    | await_primary

# Primary elements
# ----------------

# Primary elements are things like "obj.something.something", "obj[something]", "obj(something)", "obj" ...

await_primary:
    | 'await' primary
    | primary

primary:
    | primary '.' NAME
    | primary genexp
    | primary '(' [arguments] ')'
    | primary '[' slices ']'
    | atom

slices:
    | slice !','
    | ','.(slice | starred_expression)+ [',']

slice:
    | [expression] ':' [expression] [':' [expression] ]
    | named_expression

atom:
    | NAME
    | 'True'
    | 'False'
    | 'None'
    | strings
    | NUMBER
    | (tuple | group | genexp)
    | (list | listcomp)
    | (dict | set | dictcomp | setcomp)
    | '...'

group:
    | '(' (yield_expr | named_expression) ')'

# Lambda functions
# ----------------

lambdef:
    | 'lambda' [lambda_params] ':' expression

lambda_params:
    | lambda_parameters

# lambda_parameters etc. duplicates parameters but without annotations
# or type comments, and if there's no comma after a parameter, we expect
# a colon, not a close parenthesis.  (For more, see parameters above.)
#
lambda_parameters:
    | lambda_slash_no_default lambda_param_no_default* lambda_param_with_default* [lambda_star_etc]
    | lambda_slash_with_default lambda_param_with_default* [lambda_star_etc]
    | lambda_param_no_default+ lambda_param_with_default* [lambda_star_etc]
    | lambda_param_with_default+ [lambda_star_etc]
    | lambda_star_etc

lambda_slash_no_default:
    | lambda_param_no_default+ '/' ','
    | lambda_param_no_default+ '/' &':'

lambda_slash_with_default:
    | lambda_param_no_default* lambda_param_with_default+ '/' ','
    | lambda_param_no_default* lambda_param_with_default+ '/' &':'

lambda_star_etc:
    | '*' lambda_param_no_default lambda_param_maybe_default* [lambda_kwds]
    | '*' ',' lambda_param_maybe_default+ [lambda_kwds]
    | lambda_kwds

lambda_kwds:
    | '**' lambda_param_no_default

lambda_param_no_default:
    | lambda_param ','
    | lambda_param &':'
lambda_param_with_default:
    | lambda_param default ','
    | lambda_param default &':'
lambda_param_maybe_default:
    | lambda_param default? ','
    | lambda_param default? &':'
lambda_param: NAME

# LITERALS
# ========

fstring_middle:
    | fstring_replacement_field
    | FSTRING_MIDDLE
fstring_replacement_field:
    | '{' annotated_rhs '='? [fstring_conversion] [fstring_full_format_spec] '}'
fstring_conversion:
    | "!" NAME
fstring_full_format_spec:
    | ':' fstring_format_spec*
fstring_format_spec:
    | FSTRING_MIDDLE
    | fstring_replacement_field
fstring:
    | FSTRING_START fstring_middle* FSTRING_END

string: STRING
strings: (fstring|string)+

list:
    | '[' [star_named_expressions] ']'

tuple:
    | '(' [star_named_expression ',' [star_named_expressions]  ] ')'

set: '{' star_named_expressions '}'

# Dicts
# -----

dict:
    | '{' [double_starred_kvpairs] '}'

double_starred_kvpairs: ','.double_starred_kvpair+ [',']

double_starred_kvpair:
    | '**' bitwise_or
    | kvpair

kvpair: expression ':' expression

# Comprehensions & Generators
# ---------------------------

for_if_clauses:
    | for_if_clause+

for_if_clause:
    | 'async' 'for' star_targets 'in' ~ disjunction ('if' disjunction )*
    | 'for' star_targets 'in' ~ disjunction ('if' disjunction )*

listcomp:
    | '[' named_expression for_if_clauses ']'

setcomp:
    | '{' named_expression for_if_clauses '}'

genexp:
    | '(' ( assignment_expression | expression !':=') for_if_clauses ')'

dictcomp:
    | '{' kvpair for_if_clauses '}'

# FUNCTION CALL ARGUMENTS
# =======================

arguments:
    | args [','] &')'

args:
    | ','.(starred_expression | ( assignment_expression | expression !':=') !'=')+ [',' kwargs ]
    | kwargs

kwargs:
    | ','.kwarg_or_starred+ ',' ','.kwarg_or_double_starred+
    | ','.kwarg_or_starred+
    | ','.kwarg_or_double_starred+

starred_expression:
    | '*' expression

kwarg_or_starred:
    | NAME '=' expression
    | starred_expression

kwarg_or_double_starred:
    | NAME '=' expression
    | '**' expression

# ASSIGNMENT TARGETS
# ==================

# Generic targets
# ---------------

# NOTE: star_targets may contain *bitwise_or, targets may not.
star_targets:
    | star_target !','
    | star_target (',' star_target )* [',']

star_targets_list_seq: ','.star_target+ [',']

star_targets_tuple_seq:
    | star_target (',' star_target )+ [',']
    | star_target ','

star_target:
    | '*' (!'*' star_target)
    | target_with_star_atom

target_with_star_atom:
    | t_primary '.' NAME !t_lookahead
    | t_primary '[' slices ']' !t_lookahead
    | star_atom

star_atom:
    | NAME
    | '(' target_with_star_atom ')'
    | '(' [star_targets_tuple_seq] ')'
    | '[' [star_targets_list_seq] ']'

single_target:
    | single_subscript_attribute_target
    | NAME
    | '(' single_target ')'

single_subscript_attribute_target:
    | t_primary '.' NAME !t_lookahead
    | t_primary '[' slices ']' !t_lookahead

t_primary:
    | t_primary '.' NAME &t_lookahead
    | t_primary '[' slices ']' &t_lookahead
    | t_primary genexp &t_lookahead
    | t_primary '(' [arguments] ')' &t_lookahead
    | atom &t_lookahead

t_lookahead: '(' | '[' | '.'

# Targets for del statements
# --------------------------

del_targets: ','.del_target+ [',']

del_target:
    | t_primary '.' NAME !t_lookahead
    | t_primary '[' slices ']' !t_lookahead
    | del_t_atom

del_t_atom:
    | NAME
    | '(' del_target ')'
    | '(' [del_targets] ')'
    | '[' [del_targets] ']'

# TYPING ELEMENTS
# ---------------

# type_expressions allow */** but ignore them
type_expressions:
    | ','.expression+ ',' '*' expression ',' '**' expression
    | ','.expression+ ',' '*' expression
    | ','.expression+ ',' '**' expression
    | '*' expression ',' '**' expression
    | '*' expression
    | '**' expression
    | ','.expression+

func_type_comment:
    | NEWLINE TYPE_COMMENT &(NEWLINE INDENT)   # Must be followed by indented block
    | TYPE_COMMENT

# ========================= END OF THE GRAMMAR ===========================

# ========================= START OF INVALID RULES =======================

파이썬 표준 라이브러리

파이썬 언어 레퍼런스 는 파이썬 언어의 정확한 문법과 의미를 설명하고 있지만, 이 라이브러리 레퍼런스 설명서는 파이썬과 함께 배포되는 표준 라이브러리를 설명합니다. 또한, 파이썬 배포판에 일반적으로 포함되어있는 선택적 구성 요소 중 일부를 설명합니다.

파이썬의 표준 라이브러리는 매우 광범위하며, 아래 나열된 긴 목차에 표시된 대로 다양한 기능을 제공합니다. 라이브러리에는 일상적인 프로그래밍에서 발생하는 많은 문제에 대한 표준적인 해결책을 제공하는 파이썬으로 작성된 모듈뿐만 아니라, 파일 I/O와 같은 시스템 기능에 액세스하는 (C로 작성된) 내장 모듈들이 포함됩니다 (이 모듈들이 없다면 파이썬 프로그래머가 액세스할 방법은 없습니다). 이 모듈 중 일부는 플랫폼 관련 사항을 플랫폼 중립적인 API들로 추상화시킴으로써, 파이썬 프로그램의 이식성을 권장하고 개선하도록 명시적으로 설계되었습니다.

윈도우 플랫폼용 파이썬 설치 프로그램은 일반적으로 전체 표준 라이브러리를 포함하며 종종 많은 추가 구성 요소도 포함합니다. 유닉스와 같은 운영체제의 경우, 파이썬은 일반적으로 패키지 모음으로 제공되기 때문에, 운영 체제와 함께 제공되는 패키지 도구를 사용하여 선택적 구성 요소의 일부 또는 전부를 구해야 할 수 있습니다.

In addition to the standard library, there is an active collection of hundreds of thousands of components (from individual programs and modules to packages and entire application development frameworks), available from the Python Package Index [https://pypi.org].

소개

가용성에 대한 참고 사항

내장 함수

abs()

aiter()

all()

anext()

any()

ascii()

bin()

bool

breakpoint()

callable()

chr()

classmethod()

compile()

complex

delattr()

dir()

divmod()

enumerate()

eval()

exec()

filter()

float

format()

getattr()

globals()

hasattr()

hash()

help()

hex()

id()

input()

int

isinstance()

issubclass()

iter()

len()

locals()

map()

max()

min()

next()

object

oct()

open()

ord()

pow()

print()

property

repr()

reversed()

round()

setattr()

slice

sorted()

staticmethod()

sum()

super

type

vars()

zip()

__import__()

내장 상수

False

True

None

NotImplemented

Ellipsis

__debug__

site 모듈에 의해 추가된 상수들

내장형

논리값 검사

논리 연산 — and, or, not

비교

숫자 형 — int, float, complex

Boolean Type - bool

이터레이터 형

시퀀스 형 — list, tuple, range

텍스트 시퀀스 형 — str

바이너리 시퀀스 형 — bytes, bytearray, memoryview

집합 형 — set, frozenset

매핑 형 — dict

컨텍스트 관리자 형

Type Annotation Types — Generic Alias, Union

기타 내장형

특수 어트리뷰트

Integer string conversion length limitation

내장 예외

Exception context

Inheriting from built-in exceptions

베이스 클래스

구체적인 예외

경고

Exception groups

예외 계층 구조

텍스트 처리 서비스

string — Common string operations

re — Regular expression operations

difflib — Helpers for computing deltas

textwrap — Text wrapping and filling

unicodedata — Unicode Database

stringprep — Internet String Preparation

readline — GNU readline interface

rlcompleter — Completion function for GNU readline

바이너리 데이터 서비스

struct — Interpret bytes as packed binary data

codecs — Codec registry and base classes

데이터형

datetime — Basic date and time types

zoneinfo — IANA time zone support

calendar — General calendar-related functions

collections — Container datatypes

collections.abc — Abstract Base Classes for Containers

heapq — Heap queue algorithm

bisect — Array bisection algorithm

array — Efficient arrays of numeric values

weakref — 약한 참조

types — Dynamic type creation and names for built-in types

copy — Shallow and deep copy operations

pprint — Data pretty printer

reprlib — Alternate repr() implementation

enum — Support for enumerations

graphlib — Functionality to operate with graph-like structures

숫자와 수학 모듈

numbers — Numeric abstract base classes

math — Mathematical functions

cmath — Mathematical functions for complex numbers

decimal — Decimal fixed-point and floating-point arithmetic

fractions — Rational numbers

random — Generate pseudo-random numbers

statistics — Mathematical statistics functions

함수형 프로그래밍 모듈

itertools — Functions creating iterators for efficient looping

functools — Higher-order functions and operations on callable objects

operator — Standard operators as functions

파일과 디렉터리 액세스

pathlib — Object-oriented filesystem paths

os.path — Common pathname manipulations

fileinput — Iterate over lines from multiple input streams

stat — Interpreting stat() results

filecmp — File and Directory Comparisons

tempfile — Generate temporary files and directories

glob — Unix style pathname pattern expansion

fnmatch — Unix filename pattern matching

linecache — Random access to text lines

shutil — High-level file operations

데이터 지속성

pickle — Python object serialization

copyreg — Register pickle support functions

shelve — Python object persistence

marshal — Internal Python object serialization

dbm — Interfaces to Unix “databases”

sqlite3 — DB-API 2.0 interface for SQLite databases

데이터 압축 및 보관

zlib — Compression compatible with gzip

gzip — Support for gzip files

bz2 — Support for bzip2 compression

lzma — Compression using the LZMA algorithm

zipfile — Work with ZIP archives

tarfile — Read and write tar archive files

파일 형식

csv — CSV File Reading and Writing

configparser — Configuration file parser

tomllib — Parse TOML files

netrc — netrc file processing

plistlib — Generate and parse Apple .plist files

암호화 서비스

hashlib — Secure hashes and message digests

hmac — Keyed-Hashing for Message Authentication

secrets — Generate secure random numbers for managing secrets

일반 운영 체제 서비스

os — Miscellaneous operating system interfaces

io — Core tools for working with streams

time — Time access and conversions

argparse — Parser for command-line options, arguments and subcommands

logging — Logging facility for Python

logging.config — Logging configuration

logging.handlers — Logging handlers

getpass — Portable password input

curses — Terminal handling for character-cell displays

curses.textpad — curses 프로그램을 위한 텍스트 입력 위젯

curses.ascii — Utilities for ASCII characters

curses.panel — A panel stack extension for curses

platform — Access to underlying platform’s identifying data

errno — Standard errno system symbols

ctypes — A foreign function library for Python

동시 실행

threading — Thread-based parallelism

multiprocessing — Process-based parallelism

multiprocessing.shared_memory — Shared memory for direct access across processes

The concurrent package

concurrent.futures — Launching parallel tasks

subprocess — Subprocess management

sched — Event scheduler

queue — A synchronized queue class

contextvars — Context Variables

_thread — Low-level threading API

네트워킹과 프로세스 간 통신

asyncio — Asynchronous I/O

socket — Low-level networking interface

ssl — TLS/SSL wrapper for socket objects

select — Waiting for I/O completion

selectors — High-level I/O multiplexing

signal — Set handlers for asynchronous events

mmap — Memory-mapped file support

인터넷 데이터 처리

email — An email and MIME handling package

json — JSON encoder and decoder

mailbox — Manipulate mailboxes in various formats

mimetypes — Map filenames to MIME types

base64 — Base16, Base32, Base64, Base85 Data Encodings

binascii — Convert between binary and ASCII

quopri — Encode and decode MIME quoted-printable data

구조화된 마크업 처리 도구

html — HyperText Markup Language support

html.parser — Simple HTML and XHTML parser

html.entities — Definitions of HTML general entities

XML 처리 모듈

xml.etree.ElementTree — The ElementTree XML API

xml.dom — The Document Object Model API

xml.dom.minidom — Minimal DOM implementation

xml.dom.pulldom — Support for building partial DOM trees

xml.sax — Support for SAX2 parsers

xml.sax.handler — Base classes for SAX handlers

xml.sax.saxutils — SAX Utilities

xml.sax.xmlreader — Interface for XML parsers

xml.parsers.expat — Fast XML parsing using Expat

인터넷 프로토콜과 지원

webbrowser — Convenient web-browser controller

wsgiref — WSGI Utilities and Reference Implementation

urllib — URL handling modules

urllib.request — Extensible library for opening URLs

urllib.response — urllib가 사용하는 응답 클래스

urllib.parse — Parse URLs into components

urllib.error — Exception classes raised by urllib.request

urllib.robotparser — Parser for robots.txt

http — HTTP modules

http.client — HTTP protocol client

ftplib — FTP protocol client

poplib — POP3 protocol client

imaplib — IMAP4 protocol client

smtplib — SMTP protocol client

uuid — UUID objects according to RFC 9562

socketserver — A framework for network servers

http.server — HTTP servers

http.cookies — HTTP state management

http.cookiejar — Cookie handling for HTTP clients

xmlrpc — XMLRPC server and client modules

xmlrpc.client — XML-RPC client access

xmlrpc.server — Basic XML-RPC servers

ipaddress — IPv4/IPv6 manipulation library

멀티미디어 서비스

wave — Read and write WAV files

colorsys — Conversions between color systems

국제화

gettext — Multilingual internationalization services

locale — Internationalization services

프로그램 프레임워크

turtle — 터틀 그래픽

cmd — Support for line-oriented command interpreters

shlex — Simple lexical analysis

Tk를 사용한 그래픽 사용자 인터페이스

tkinter — Python interface to Tcl/Tk

tkinter.colorchooser — Color choosing dialog

tkinter.font — Tkinter font wrapper

Tkinter 대화 상자

tkinter.messagebox — Tkinter message prompts

tkinter.scrolledtext — Scrolled Text Widget

tkinter.dnd — Drag and drop support

tkinter.ttk — Tk themed widgets

IDLE

개발 도구

typing — 형 힌트 지원

pydoc — Documentation generator and online help system

파이썬 개발 모드

doctest — Test interactive Python examples

unittest — Unit testing framework

unittest.mock — mock object library

unittest.mock — getting started

test — Regression tests package for Python

test.support — 파이썬 테스트 스위트용 유틸리티

test.support.socket_helper — 소켓 테스트용 유틸리티

test.support.script_helper — 파이썬 실행 테스트용 유틸리티

test.support.bytecode_helper — 올바른 바이트 코드 생성 테스트를 위한 지원 도구

test.support.threading_helper — Utilities for threading tests

test.support.os_helper — Utilities for os tests

test.support.import_helper — Utilities for import tests

test.support.warnings_helper — Utilities for warnings tests

디버깅과 프로파일링

감사 이벤트 표

bdb — Debugger framework

faulthandler — Dump the Python traceback

pdb — 파이썬 디버거

파이썬 프로파일러

timeit — Measure execution time of small code snippets

trace — Trace or track Python statement execution

tracemalloc — Trace memory allocations

소프트웨어 패키징 및 배포

ensurepip — Bootstrapping the pip installer

venv — Creation of virtual environments

zipapp — Manage executable Python zip archives

파이썬 실행시간 서비스

sys — System-specific parameters and functions

sys.monitoring — Execution event monitoring

sysconfig — Provide access to Python’s configuration information

builtins — Built-in objects

__main__ — Top-level code environment

warnings — Warning control

dataclasses — Data Classes

contextlib — with 문 컨텍스트를 위한 유틸리티

abc — Abstract Base Classes

atexit — Exit handlers

traceback — Print or retrieve a stack traceback

__future__ — Future statement definitions

gc — Garbage Collector interface

inspect — Inspect live objects

annotationlib — Functionality for introspecting annotations

site — Site-specific configuration hook

사용자 정의 파이썬 인터프리터

code — Interpreter base classes

codeop — Compile Python code

모듈 임포트 하기

zipimport — Import modules from Zip archives

pkgutil — Package extension utility

modulefinder — Find modules used by a script

runpy — Locating and executing Python modules

importlib — import의 구현

importlib.resources – Package resource reading, opening and access

importlib.resources.abc – Abstract base classes for resources

importlib.metadata – Accessing package metadata

The initialization of the sys.path module search path

파이썬 언어 서비스

ast — Abstract Syntax Trees

symtable — Access to the compiler’s symbol tables

token — Constants used with Python parse trees

keyword — Testing for Python keywords

tokenize — Tokenizer for Python source

tabnanny — Detection of ambiguous indentation

pyclbr — Python module browser support

py_compile — Compile Python source files

compileall — Byte-compile Python libraries

dis — Disassembler for Python bytecode

pickletools — Tools for pickle developers

MS 윈도우 특정 서비스

msvcrt — Useful routines from the MS VC++ runtime

winreg — Windows registry access

winsound — Sound-playing interface for Windows

유닉스 특정 서비스

posix — The most common POSIX system calls

pwd — The password database

grp — The group database

termios — POSIX style tty control

tty — Terminal control functions

pty — Pseudo-terminal utilities

fcntl — The fcntl and ioctl system calls

resource — Resource usage information

syslog — Unix syslog library routines

Modules command-line interface (CLI)

대체된 모듈

getopt — C-style parser for command line options

optparse — Parser for command line options

Removed Modules

Security Considerations

소개

“파이썬 라이브러리”에는 여러 가지 구성 요소가 포함되어 있습니다.

여기에는 일반적으로 숫자 및 리스트와 같이 언어의 “핵심” 부분으로 간주하는 데이터형이 포함됩니다. 이러한 형의 경우, 파이썬 언어 핵심은 리터럴의 형식을 정의하고 그 의미에 몇 가지 제약을 가하지만, 의미를 완전히 정의하지는 않습니다. (반면에, 언어 핵심은 연산자의 철자법과 우선순위와 같은 문법적 속성을 정의합니다.)

라이브러리는 또한 내장 함수와 예외를 포함합니다 — import 문을 쓰지 않고도 모든 파이썬 코드에서 사용할 수 있는 객체들입니다. 이들 중 일부는 언어 핵심에 의해 정의되지만, 핵심 의미에 필수적인 것은 아니며 여기에서 설명합니다.

그러나 라이브러리 대부분은 모듈 컬렉션으로 구성됩니다. 이 컬렉션을 나누는 데는 여러 가지 방법이 있습니다. 일부 모듈은 C로 작성되고 파이썬 인터프리터에 내장되어 있습니다; 다른 것은 파이썬으로 작성되고 소스 형식으로 임포트 됩니다. 일부 모듈은 스택 추적 인쇄와 같이 파이썬에 매우 특정한 인터페이스를 제공합니다; 일부는 특정 하드웨어에 대한 액세스와 같이 운영 체제에 특정한 인터페이스를 제공합니다; 다른 것은 월드 와이드 웹과 같은 응용 프로그램 영역에 특정한 인터페이스를 제공합니다. 일부 모듈은 파이썬의 모든 버전과 이식에서 사용할 수 있습니다; 다른 것은 하위 시스템이 지원하거나 요구할 때만 사용할 수 있습니다; 그러나 다른 것들은 파이썬이 컴파일되고 설치될 때 특정 설정 옵션이 선택되었을 때만 사용할 수 있습니다.

이 설명서는 “안쪽에서부터 밖으로” 구성되어 있습니다. 먼저 내장 함수, 데이터형 및 예외, 마지막으로 관련 모듈의 장으로 그룹화된 모듈들을 설명합니다.

즉, 처음부터 이 설명서를 읽고, 지루할 때 다음 장으로 건너뛰면, 파이썬 라이브러리가 지원하는 사용 가능한 모듈과 응용 프로그램 영역에 대한 적당한 개요를 얻게 됩니다. 물론 소설처럼 읽을 필요는 없습니다. (설명서 앞에 있는) 목차를 검색하거나, (뒤에 있는) 색인에서 특정 함수, 모듈 또는 용어를 찾을 수도 있습니다. 그리고 마지막으로, 무작위 주제에 대해 배우는 것을 즐긴다면, 임의의 페이지 번호 (모듈 random 참조)를 선택하고 한두 섹션을 읽으면 됩니다. 이 설명서의 섹션을 읽는 순서와 관계없이, 내장 함수 장에서 시작하는 것이 도움이 되는데, 설명서의 나머지 부분은 이 내용에 익숙하다고 가정하기 때문입니다.

쇼를 시작합시다!

가용성에 대한 참고 사항

“가용성: 유닉스” 참고 사항은 이 기능이 유닉스 시스템에서 일반적으로 발견된다는 것을 뜻합니다. 특정 운영 체제에 이 기능이 존재하는지에 관한 어떠한 주장도 하지 않습니다.

If not separately noted, all functions that claim “Availability: Unix” are supported on macOS, iOS and Android, all of which build on a Unix core.

If an availability note contains both a minimum Kernel version and a minimum libc version, then both conditions must hold. For example a feature with note Availability: Linux >= 3.17 with glibc >= 2.27 requires both Linux 3.17 or newer and glibc 2.27 or newer.

WebAssembly platforms

The WebAssembly [https://webassembly.org/] platforms wasm32-emscripten (Emscripten [https://emscripten.org/]) and wasm32-wasi (WASI [https://wasi.dev/]) provide a subset of POSIX APIs. WebAssembly runtimes and browsers are sandboxed and have limited access to the host and external resources. Any Python standard library module that uses processes, threading, networking, signals, or other forms of inter-process communication (IPC), is either not available or may not work as on other Unix-like systems. File I/O, file system, and Unix permission-related functions are restricted, too. Emscripten does not permit blocking I/O. Other blocking operations like sleep() block the browser event loop.

The properties and behavior of Python on WebAssembly platforms depend on the Emscripten [https://emscripten.org/]-SDK or WASI [https://wasi.dev/]-SDK version, WASM runtimes (browser, NodeJS, wasmtime [https://wasmtime.dev/]), and Python build time flags. WebAssembly, Emscripten, and WASI are evolving standards; some features like networking may be supported in the future.

For Python in the browser, users should consider Pyodide [https://pyodide.org/] or PyScript [https://pyscript.net/]. PyScript is built on top of Pyodide, which itself is built on top of CPython and Emscripten. Pyodide provides access to browsers’ JavaScript and DOM APIs as well as limited networking capabilities with JavaScript’s XMLHttpRequest and Fetch APIs.

Process-related APIs are not available or always fail with an error. That includes APIs that spawn new processes (fork(), execve()), wait for processes (waitpid()), send signals (kill()), or otherwise interact with processes. The subprocess is importable but does not work.

The socket module is available, but is limited and behaves differently from other platforms. On Emscripten, sockets are always non-blocking and require additional JavaScript code and helpers on the server to proxy TCP through WebSockets; see Emscripten Networking [https://emscripten.org/docs/porting/networking.html] for more information. WASI snapshot preview 1 only permits sockets from an existing file descriptor.

Some functions are stubs that either don’t do anything and always return hardcoded values.

Functions related to file descriptors, file permissions, file ownership, and links are limited and don’t support some operations. For example, WASI does not permit symlinks with absolute file names.

Mobile platforms

Android and iOS are, in most respects, POSIX operating systems. File I/O, socket handling, and threading all behave as they would on any POSIX operating system. However, there are several major differences:

Mobile platforms can only use Python in “embedded” mode. There is no Python REPL, and no ability to use separate executables such as python or pip. To add Python code to your mobile app, you must use the Python embedding API. For more details, see Using Python on Android and Using Python on iOS.

Subprocesses:

On Android, creating subprocesses is possible but officially unsupported [https://issuetracker.google.com/issues/128554619#comment4]. In particular, Android does not support any part of the System V IPC API, so multiprocessing is not available.

An iOS app cannot use any form of subprocessing, multiprocessing, or inter-process communication. If an iOS app attempts to create a subprocess, the process creating the subprocess will either lock up, or crash. An iOS app has no visibility of other applications that are running, nor any ability to communicate with other running applications, outside of the iOS-specific APIs that exist for this purpose.

Mobile apps have limited access to modify system resources (such as the system clock). These resources will often be readable, but attempts to modify those resources will usually fail.

Console input and output:

On Android, the native stdout and stderr are not connected to anything, so Python installs its own streams which redirect messages to the system log. These can be seen under the tags python.stdout and python.stderr respectively.

iOS apps have a limited concept of console output. stdout and stderr exist, and content written to stdout and stderr will be visible in logs when running in Xcode, but this content won’t be recorded in the system log. If a user who has installed your app provides their app logs as a diagnostic aid, they will not include any detail written to stdout or stderr.

Mobile apps have no usable stdin at all. While apps can display an on-screen keyboard, this is a software feature, not something that is attached to stdin.

As a result, Python modules that involve console manipulation (such as curses and readline) are not available on mobile platforms.

내장 함수

파이썬 인터프리터에는 항상 사용할 수 있는 많은 함수와 형이 내장되어 있습니다. 여기에서 알파벳 순으로 나열합니다.

내장 함수

A

abs()

aiter()

all()

anext()

any()

ascii()

B

bin()

bool()

breakpoint()

bytearray()

bytes()

C

callable()

chr()

classmethod()

compile()

complex()

D

delattr()

dict()

dir()

divmod()

E

enumerate()

eval()

exec()

F

filter()

float()

format()

frozenset()

G

getattr()

globals()

H

hasattr()

hash()

help()

hex()

I

id()

input()

int()

isinstance()

issubclass()

iter()

L

len()

list()

locals()

M

map()

max()

memoryview()

min()

N

next()

O

object()

oct()

open()

ord()

P

pow()

print()

property()

R

range()

repr()

reversed()

round()

S

set()

setattr()

slice()

sorted()

staticmethod()

str()

sum()

super()

T

tuple()

type()

V

vars()

Z

zip()

_

__import__()

abs(x)

Return the absolute value of a number. The argument may be an integer, a floating-point number, or an object implementing __abs__(). If the argument is a complex number, its magnitude is returned.

aiter(async_iterable)

Return an asynchronous iterator for an asynchronous iterable. Equivalent to calling x.__aiter__().

Note: Unlike iter(), aiter() has no 2-argument variant.

Added in version 3.10.

all(iterable)

iterable 의 모든 요소가 참이면 (또는 iterable 이 비어있으면) True 를 돌려줍니다. 다음과 동등합니다:

def all(iterable):
    for element in iterable:
        if not element:
            return False
    return True

awaitable anext(async_iterator)

awaitable anext(async_iterator, default)

When awaited, return the next item from the given asynchronous iterator, or default if given and the iterator is exhausted.

This is the async variant of the next() builtin, and behaves similarly.

This calls the __anext__() method of async_iterator, returning an awaitable. Awaiting this returns the next value of the iterator. If default is given, it is returned if the iterator is exhausted, otherwise StopAsyncIteration is raised.

Added in version 3.10.

any(iterable)

iterable 의 요소 중 어느 하나라도 참이면 True 를 돌려줍니다. iterable이 비어 있으면 False 를 돌려줍니다. 다음과 동등합니다:

def any(iterable):
    for element in iterable:
        if element:
            return True
    return False

ascii(object)

As repr(), return a string containing a printable representation of an object, but escape the non-ASCII characters in the string returned by repr() using \x, \u, or \U escapes. This generates a string similar to that returned by repr() in Python 2.

bin(x)

Convert an integer number to a binary string prefixed with “0b”. The result is a valid Python expression. If x is not a Python int object, it has to define an __index__() method that returns an integer. Some examples:

>>> bin(3)
'0b11'
>>> bin(-10)
'-0b1010'

If the prefix “0b” is desired or not, you can use either of the following ways.

>>> format(14, '#b'), format(14, 'b')
('0b1110', '1110')
>>> f'{14:#b}', f'{14:b}'
('0b1110', '1110')

자세한 내용은 format()을 보세요.

class bool(object=False, /)

Return a Boolean value, i.e. one of True or False. The argument is converted using the standard truth testing procedure. If the argument is false or omitted, this returns False; otherwise, it returns True. The bool class is a subclass of int (see 숫자 형 — int, float, complex). It cannot be subclassed further. Its only instances are False and True (see Boolean Type - bool).

버전 3.7에서 변경: The parameter is now positional-only.

breakpoint(*args, **kws)

This function drops you into the debugger at the call site. Specifically, it calls sys.breakpointhook(), passing args and kws straight through. By default, sys.breakpointhook() calls pdb.set_trace() expecting no arguments. In this case, it is purely a convenience function so you don’t have to explicitly import pdb or type as much code to enter the debugger. However, sys.breakpointhook() can be set to some other function and breakpoint() will automatically call that, allowing you to drop into the debugger of choice. If sys.breakpointhook() is not accessible, this function will raise RuntimeError.

By default, the behavior of breakpoint() can be changed with the PYTHONBREAKPOINT environment variable. See sys.breakpointhook() for usage details.

Note that this is not guaranteed if sys.breakpointhook() has been replaced.

breakpointhook을 인자로 감사 이벤트(auditing event) builtins.breakpoint를 발생시킵니다.

Added in version 3.7.

class bytearray(source=b'')

class bytearray(source, encoding)

class bytearray(source, encoding, errors)

새로운 바이트 배열을 돌려줍니다. bytearray 클래스는 0 <= x < 256 범위에 있는 정수의 가변 시퀀스입니다. bytes 형이 가진 대부분의 메서드뿐만 아니라 (바이트열 과 바이트 배열 연산 를 보세요), 가변 시퀀스 형 에 기술된 가변 시퀀스의 일반적인 메서드 대부분을 갖고 있습니다.

선택적 source 매개변수는 몇 가지 다른 방법으로 배열을 초기화하는 데 사용할 수 있습니다:

문자열 이면, 반드시 encoding 매개변수도 제공해야 합니다 (그리고 선택적으로 errors 도); 그러면 bytearray() 는 str.encode() 를 사용하여 문자열을 바이트로 변환합니다.

정수 면, 배열은 그 크기를 갖고, 널 바이트로 초기화됩니다.

버퍼 인터페이스를 제공하는 객체면, 객체의 읽기 전용 버퍼가 바이트 배열을 초기화하는 데 사용됩니다.

이터러블 이면, 범위 0 <= x < 256 의 정수를 제공하는 이터러블이어야 하고, 그 값들이 배열의 초기 내용물로 사용됩니다.

인자가 없으면 크기 0의 배열이 만들어집니다.

바이너리 시퀀스 형 — bytes, bytearray, memoryview와 바이트 배열 객체 도 보세요.

class bytes(source=b'')

class bytes(source, encoding)

class bytes(source, encoding, errors)

Return a new “bytes” object which is an immutable sequence of integers in the range 0 <= x < 256. bytes is an immutable version of bytearray – it has the same non-mutating methods and the same indexing and slicing behavior.

따라서 생성자 인자는 bytearray() 와 같이 해석됩니다.

바이트열 객체는 리터럴을 사용하여 만들 수도 있습니다 (문자열과 바이트열 리터럴 를 보세요).

바이너리 시퀀스 형 — bytes, bytearray, memoryview, 바이트열 객체 및 바이트열 과 바이트 배열 연산 도 보세요.

callable(object)

Return True if the object argument appears callable, False if not. If this returns True, it is still possible that a call fails, but if it is False, calling object will never succeed. Note that classes are callable (calling a class returns a new instance); instances are callable if their class has a __call__() method.

Added in version 3.2: 이 함수는 파이썬 3.0에서 먼저 제거된 다음 파이썬 3.2에서 다시 도입했습니다.

chr(i)

유니코드 코드 포인트가 정수 i 인 문자를 나타내는 문자열을 돌려줍니다. 예를 들어, chr(97) 은 문자열 'a' 를 돌려주고, chr(8364) 는 문자열 '€' 를 돌려줍니다. 이 것은 ord() 의 반대입니다.

인자의 유효 범위는 0에서 1,114,111(16진수로 0x10FFFF)까지입니다. i 가 이 범위 밖에 있을 때 ValueError 가 발생합니다.

@classmethod

메서드를 클래스 메서드로 변환합니다.

A class method receives the class as an implicit first argument, just like an instance method receives the instance. To declare a class method, use this idiom:

class C:
    @classmethod
    def f(cls, arg1, arg2): ...

@classmethod 형식은 함수 데코레이터 입니다 – 자세한 내용은 함수 정의를 보세요.

클래스 메서드는 클래스 (C.f() 처럼) 또는 인스턴스 (C().f() 처럼) 를 통해 호출할 수 있습니다. 인스턴스는 클래스만 참조하고 무시됩니다. 파생 클래스에 대해 클래스 메서드가 호출되면, 파생 클래스 객체가 묵시적인 첫 번째 인자로 전달됩니다.

클래스 메서드는 C++ 또는 자바의 정적 메서드와 다릅니다. 그것들을 원하면, 이 섹션의 staticmethod()를 보세요. 클래스 메서드에 대한 더 자세한 정보는, 표준형 계층을 참고하세요.

버전 3.9에서 변경: 클래스 메서드는 이제 property()와 같은 다른 디스크립터를 래핑 할 수 있습니다.

버전 3.10에서 변경: Class methods now inherit the method attributes (__module__, __name__, __qualname__, __doc__ and __annotations__) and have a new __wrapped__ attribute.

Deprecated since version 3.11, removed in version 3.13: Class methods can no longer wrap other descriptors such as property().

compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)

source 를 코드 또는 AST 객체로 컴파일합니다. 코드 객체는 exec() 또는 eval() 로 실행할 수 있습니다. source 는 일반 문자열, 바이트열 또는 AST 객체 일 수 있습니다. AST 객체로 작업하는 방법에 대한 정보는 ast 모듈 문서를 참조하세요.

filename 인자는 코드를 읽은 파일을 제공해야 합니다; 파일에서 읽지 않으면 인식 가능한 값을 전달합니다 ('<string>' 이 일반적으로 사용됩니다).

mode 인자는 컴파일해야 하는 코드 종류를 지정합니다; source 가 문장의 시퀀스로 구성되어 있다면 exec, 단일 표현식으로 구성되어 있다면 'eval', 단일 대화형 문장으로 구성되면 'single' 이 될 수 있습니다 (마지막의 경우 None 이외의 값으로 구해지는 표현식 문은 인쇄됩니다).

선택적 인자 flags 와 dont_inherit 는 어떤 컴파일러 옵션이 활성화되어야 하고 어떤 퓨처 기능이 허락되어야 하는지 제어합니다. 둘 다 제공되지 않는 경우 (또는 둘 다 0의 경우), 코드는 compile() 을 호출하는 코드에 적용되고 있는 것과 같은 플래그로 컴파일됩니다. flags 인자가 주어지고, dont_inherit 가 없으면 (또는 0) 원래 사용될 것에 더해 flags 인자로 지정된 컴파일러 옵션과 퓨처 문이 사용됩니다. dont_inherit 가 0이 아닌 정수면 flags 인자가 사용됩니다 – 둘러싼 코드의 플래그(퓨처 기능과 컴파일러 옵션)는 무시됩니다.

컴파일러 옵션과 퓨처 문은 여러 개의 옵션을 지정하기 위해 비트 OR 될 수 있는 비트에 의해 지정됩니다. 주어진 퓨처 기능을 지정하는 데 필요한 비트 필드는 __future__ 모듈의 _Feature 인스턴스에서 compiler_flag 어트리뷰트로 찾을 수 있습니다. 컴파일러 플래그는 PyCF_ 접두사로 ast 모듈에서 찾을 수 있습니다.

인자 optimize 는 컴파일러의 최적화 수준을 지정합니다; 기본값 -1 은 -O 옵션에 의해 주어진 인터프리터의 최적화 수준을 선택합니다. 명시적 수준은 0 (최적화 없음, __debug__ 이 참입니다), 1 (assert가 제거됩니다, __debug__ 이 거짓입니다) 또는 2 다 (독스트링도 제거됩니다).

이 함수는 컴파일된 소스가 올바르지 않으면 SyntaxError 를 일으키고, 소스에 널 바이트가 들어있는 경우 ValueError 를 일으킵니다.

파이썬 코드를 AST 표현으로 파싱하려면, ast.parse() 를 보세요.

source와 filename을 인자로 감사 이벤트(auditing event) compile을 발생시킵니다. 이 이벤트는 묵시적 컴파일로 인해 발생할 수도 있습니다.

참고

'single' 또는 'eval' mode로 여러 줄 코드를 가진 문자열을 컴파일할 때, 적어도 하나의 개행 문자로 입력을 끝내야 합니다. 이것은 code 모듈에서 문장이 불완전한지 완전한지를 쉽게 탐지하게 하기 위함입니다.

경고

파이썬의 AST 컴파일러에서 스택 깊이 제한으로 인해, AST 객체로 컴파일할 때 충분히 크고 복잡한 문자열로 파이썬 인터프리터가 크래시를 일으키도록 만들 수 있습니다.

버전 3.2에서 변경: Allowed use of Windows and Mac newlines. Also, input in 'exec' mode does not have to end in a newline anymore. Added the optimize parameter.

버전 3.5에서 변경: 이전에는, source 에서 널 바이트가 발견될 때 TypeError 가 발생했습니다.

Added in version 3.8: 이제 ast.PyCF_ALLOW_TOP_LEVEL_AWAIT를 flags로 전달하여 최상위 수준 await, async for 및 async with를 지원할 수 있습니다.

class complex(number=0, /)

class complex(string, /)

class complex(real=0, imag=0)

Convert a single string or number to a complex number, or create a complex number from real and imaginary parts.

Examples:

>>> complex('+1.23')
(1.23+0j)
>>> complex('-4.5j')
-4.5j
>>> complex('-1.23+4.5j')
(-1.23+4.5j)
>>> complex('\t( -1.23+4.5J )\n')
(-1.23+4.5j)
>>> complex('-Infinity+NaNj')
(-inf+nanj)
>>> complex(1.23)
(1.23+0j)
>>> complex(imag=-4.5)
-4.5j
>>> complex(-1.23, 4.5)
(-1.23+4.5j)

If the argument is a string, it must contain either a real part (in the same format as for float()) or an imaginary part (in the same format but with a 'j' or 'J' suffix), or both real and imaginary parts (the sign of the imaginary part is mandatory in this case). The string can optionally be surrounded by whitespaces and the round parentheses '(' and ')', which are ignored. The string must not contain whitespace between '+', '-', the 'j' or 'J' suffix, and the decimal number. For example, complex('1+2j') is fine, but complex('1 + 2j') raises ValueError. More precisely, the input must conform to the complexvalue production rule in the following grammar, after parentheses and leading and trailing whitespace characters are removed:

complexvalue ::=  floatvalue |
                  floatvalue ("j" | "J") |
                  floatvalue sign absfloatvalue ("j" | "J")

If the argument is a number, the constructor serves as a numeric conversion like int and float. For a general Python object x, complex(x) delegates to x.__complex__(). If __complex__() is not defined then it falls back to __float__(). If __float__() is not defined then it falls back to __index__().

If two arguments are provided or keyword arguments are used, each argument may be any numeric type (including complex). If both arguments are real numbers, return a complex number with the real component real and the imaginary component imag. If both arguments are complex numbers, return a complex number with the real component real.real-imag.imag and the imaginary component real.imag+imag.real. If one of arguments is a real number, only its real component is used in the above expressions.

See also complex.from_number() which only accepts a single numeric argument.

If all arguments are omitted, returns 0j.

복소수 형은 숫자 형 — int, float, complex 에서 설명합니다.

버전 3.6에서 변경: 코드 리터럴 처럼 숫자를 밑줄로 그룹화할 수 있습니다.

버전 3.8에서 변경: Falls back to __index__() if __complex__() and __float__() are not defined.

버전 3.14부터 폐지됨: Passing a complex number as the real or imag argument is now deprecated; it should only be passed as a single positional argument.

delattr(object, name)

This is a relative of setattr(). The arguments are an object and a string. The string must be the name of one of the object’s attributes. The function deletes the named attribute, provided the object allows it. For example, delattr(x, 'foobar') is equivalent to del x.foobar. name need not be a Python identifier (see setattr()).

class dict(**kwarg)

class dict(mapping, **kwarg)

class dict(iterable, **kwarg)

새 딕셔너리를 만듭니다. dict 객체는 딕셔너리 클래스입니다. 이 클래스에 대한 설명서는 dict 및 매핑 형 — dict 을 보세요.

다른 컨테이너의 경우 list, set 및 tuple 클래스와 collections 모듈을 보세요.

dir()

dir(object)

인자가 없으면, 현재 지역 스코프에 있는 이름들의 리스트를 돌려줍니다. 인자가 있으면, 해당 객체에 유효한 어트리뷰트들의 리스트를 돌려주려고 시도합니다.

If the object has a method named __dir__(), this method will be called and must return the list of attributes. This allows objects that implement a custom __getattr__() or __getattribute__() function to customize the way dir() reports their attributes.

If the object does not provide __dir__(), the function tries its best to gather information from the object’s __dict__ attribute, if defined, and from its type object. The resulting list is not necessarily complete and may be inaccurate when the object has a custom __getattr__().

기본 dir() 메커니즘은 다른 형의 객체에 대해서 다르게 동작하는데, 완전한 정보보다는 가장 적절한 정보를 만들려고 시도하기 때문입니다:

객체가 모듈 객체면, 리스트에는 모듈 어트리뷰트의 이름이 포함됩니다.

객체가 형 또는 클래스 객체면, 리스트에는 그것의 어트리뷰트 이름과 베이스의 어트리뷰트 이름들이 재귀적으로 포함됩니다.

그 밖의 경우, 리스트에는 객체의 어트리뷰트 이름, 해당 클래스의 어트리뷰트 이름 및 해당 클래스의 베이스 클래스들의 어트리뷰트 이름을 재귀적으로 포함합니다.

결과 리스트는 알파벳 순으로 정렬됩니다. 예를 들어:

>>> import struct
>>> dir()   # show the names in the module namespace
['__builtins__', '__name__', 'struct']
>>> dir(struct)   # show the names in the struct module
['Struct', '__all__', '__builtins__', '__cached__', '__doc__', '__file__',
 '__initializing__', '__loader__', '__name__', '__package__',
 '_clearcache', 'calcsize', 'error', 'pack', 'pack_into',
 'unpack', 'unpack_from']
>>> class Shape:
...     def __dir__(self):
...         return ['area', 'perimeter', 'location']
...
>>> s = Shape()
>>> dir(s)
['area', 'location', 'perimeter']

참고

dir() 은 주로 대화형 프롬프트에서의 사용 편의를 위해 제공되기 때문에, 엄격하거나 일관되게 정의된 이름 집합을 제공하기보다 흥미로운 이름 집합을 제공하려고 시도하며, 상세한 동작은 배포마다 변경될 수 있습니다. 예를 들어, 인자가 클래스면 메타 클래스 어트리뷰트는 결과 리스트에 없습니다.

divmod(a, b)

Take two (non-complex) numbers as arguments and return a pair of numbers consisting of their quotient and remainder when using integer division. With mixed operand types, the rules for binary arithmetic operators apply. For integers, the result is the same as (a // b, a % b). For floating-point numbers the result is (q, a % b), where q is usually math.floor(a / b) but may be 1 less than that. In any case q * b + a % b is very close to a, if a % b is non-zero it has the same sign as b, and 0 <= abs(a % b) < abs(b).

enumerate(iterable, start=0)

열거 객체를 돌려줍니다. iterable 은 시퀀스, 이터레이터 또는 이터레이션을 지원하는 다른 객체여야 합니다. enumerate() 에 의해 반환된 이터레이터의 __next__() 메서드는 카운트 (기본값 0을 갖는 start 부터)와 iterable 을 이터레이션 해서 얻어지는 값을 포함하는 튜플을 돌려줍니다.

>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']
>>> list(enumerate(seasons))
[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
>>> list(enumerate(seasons, start=1))
[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]

다음과 동등합니다:

def enumerate(iterable, start=0):
    n = start
    for elem in iterable:
        yield n, elem
        n += 1

eval(source, /, globals=None, locals=None)

매개변수:

source (str | code object) – A Python expression.

globals (dict | None) – The global namespace (default: None).

locals (mapping | None) – The local namespace (default: None).

반환:

The result of the evaluated expression.

Raises:

Syntax errors are reported as exceptions.

경고

This function executes arbitrary code. Calling it with user-supplied input may lead to security vulnerabilities.

The expression argument is parsed and evaluated as a Python expression (technically speaking, a condition list) using the globals and locals mappings as global and local namespace. If the globals dictionary is present and does not contain a value for the key __builtins__, a reference to the dictionary of the built-in module builtins is inserted under that key before expression is parsed. That way you can control what builtins are available to the executed code by inserting your own __builtins__ dictionary into globals before passing it to eval(). If the locals mapping is omitted it defaults to the globals dictionary. If both mappings are omitted, the expression is executed with the globals and locals in the environment where eval() is called. Note, eval() will only have access to the nested scopes (non-locals) in the enclosing environment if they are already referenced in the scope that is calling eval() (e.g. via a nonlocal statement).

Example:

>>> x = 1
>>> eval('x+1')
2

This function can also be used to execute arbitrary code objects (such as those created by compile()). In this case, pass a code object instead of a string. If the code object has been compiled with 'exec' as the mode argument, eval()'s return value will be None.

Hints: dynamic execution of statements is supported by the exec() function. The globals() and locals() functions return the current global and local dictionary, respectively, which may be useful to pass around for use by eval() or exec().

If the given source is a string, then leading and trailing spaces and tabs are stripped.

리터럴 만 포함 된 표현식의 값을 안전하게 구할 수 있는 함수 ast.literal_eval() 를 보세요.

코드 객체를 인자로 감사 이벤트(auditing event) exec를 발생시킵니다. 코드 컴파일 이벤트도 발생할 수 있습니다.

버전 3.13에서 변경: The globals and locals arguments can now be passed as keywords.

버전 3.13에서 변경: The semantics of the default locals namespace have been adjusted as described for the locals() builtin.

exec(source, /, globals=None, locals=None, *, closure=None)

경고

This function executes arbitrary code. Calling it with user-supplied input may lead to security vulnerabilities.

This function supports dynamic execution of Python code. source must be either a string or a code object. If it is a string, the string is parsed as a suite of Python statements which is then executed (unless a syntax error occurs). [1] If it is a code object, it is simply executed. In all cases, the code that’s executed is expected to be valid as file input (see the section 파일 입력 in the Reference Manual). Be aware that the nonlocal, yield, and return statements may not be used outside of function definitions even within the context of code passed to the exec() function. The return value is None.

In all cases, if the optional parts are omitted, the code is executed in the current scope. If only globals is provided, it must be a dictionary (and not a subclass of dictionary), which will be used for both the global and the local variables. If globals and locals are given, they are used for the global and local variables, respectively. If provided, locals can be any mapping object. Remember that at the module level, globals and locals are the same dictionary.

참고

When exec gets two separate objects as globals and locals, the code will be executed as if it were embedded in a class definition. This means functions and classes defined in the executed code will not be able to access variables assigned at the top level (as the “top level” variables are treated as class variables in a class definition).

globals 딕셔너리가 __builtins__ 를 키로 하는 값을 갖고 있지 않으면, 그 키로 내장 모듈 builtins 에 대한 참조가 삽입됩니다. 이런 식으로 exec() 에 전달하기 전에 globals 에 여러분 자신의 __builtins__ 딕셔너리를 삽입함으로써, 실행되는 코드에 어떤 내장 객체들이 제공될지를 제어할 수 있습니다.

The closure argument specifies a closure–a tuple of cellvars. It’s only valid when the object is a code object containing free (closure) variables. The length of the tuple must exactly match the length of the code object’s co_freevars attribute.

코드 객체를 인자로 감사 이벤트(auditing event) exec를 발생시킵니다. 코드 컴파일 이벤트도 발생할 수 있습니다.

참고

The built-in functions globals() and locals() return the current global and local namespace, respectively, which may be useful to pass around for use as the second and third argument to exec().

참고

The default locals act as described for function locals() below. Pass an explicit locals dictionary if you need to see effects of the code on locals after function exec() returns.

버전 3.11에서 변경: Added the closure parameter.

버전 3.13에서 변경: The globals and locals arguments can now be passed as keywords.

버전 3.13에서 변경: The semantics of the default locals namespace have been adjusted as described for the locals() builtin.

filter(function, iterable)

Construct an iterator from those elements of iterable for which function is true. iterable may be either a sequence, a container which supports iteration, or an iterator. If function is None, the identity function is assumed, that is, all elements of iterable that are false are removed.

filter(function, iterable) 는 function이 None 이 아닐 때 제너레이터 표현식 (item for item in iterable if function(item)) 과, None 일 때 (item for item in iterable if item) 와 동등함에 유의하세요.

See itertools.filterfalse() for the complementary function that returns elements of iterable for which function is false.

class float(number=0.0, /)

class float(string, /)

Return a floating-point number constructed from a number or a string.

Examples:

>>> float('+1.23')
1.23
>>> float('   -12345\n')
-12345.0
>>> float('1e-003')
0.001
>>> float('+1E6')
1000000.0
>>> float('-Infinity')
-inf

If the argument is a string, it should contain a decimal number, optionally preceded by a sign, and optionally embedded in whitespace. The optional sign may be '+' or '-'; a '+' sign has no effect on the value produced. The argument may also be a string representing a NaN (not-a-number), or positive or negative infinity. More precisely, the input must conform to the floatvalue production rule in the following grammar, after leading and trailing whitespace characters are removed:

sign          ::=  "+" | "-"
infinity      ::=  "Infinity" | "inf"
nan           ::=  "nan"
digit         ::=  <a Unicode decimal digit, i.e. characters in Unicode general category Nd>
digitpart     ::=  digit (["_"] digit)*
number        ::=  [digitpart] "." digitpart | digitpart ["."]
exponent      ::=  ("e" | "E") [sign] digitpart
floatnumber   ::=  number [exponent]
absfloatvalue ::=  floatnumber | infinity | nan
floatvalue    ::=  [sign] absfloatvalue

Case is not significant, so, for example, “inf”, “Inf”, “INFINITY”, and “iNfINity” are all acceptable spellings for positive infinity.

Otherwise, if the argument is an integer or a floating-point number, a floating-point number with the same value (within Python’s floating-point precision) is returned. If the argument is outside the range of a Python float, an OverflowError will be raised.

For a general Python object x, float(x) delegates to x.__float__(). If __float__() is not defined then it falls back to __index__().

See also float.from_number() which only accepts a numeric argument.

인자가 주어지지 않으면, 0.0 을 돌려줍니다.

float 형은 숫자 형 — int, float, complex 에 설명되어 있습니다.

버전 3.6에서 변경: 코드 리터럴 처럼 숫자를 밑줄로 그룹화할 수 있습니다.

버전 3.7에서 변경: The parameter is now positional-only.

버전 3.8에서 변경: Falls back to __index__() if __float__() is not defined.

format(value, format_spec='')

Convert a value to a “formatted” representation, as controlled by format_spec. The interpretation of format_spec will depend on the type of the value argument; however, there is a standard formatting syntax that is used by most built-in types: 포맷 명세 미니 언어.

기본 format_spec 은 빈 문자열이며 일반적으로 str(value) 를 호출하는 것과 같은 효과를 줍니다.

A call to format(value, format_spec) is translated to type(value).__format__(value, format_spec) which bypasses the instance dictionary when searching for the value’s __format__() method. A TypeError exception is raised if the method search reaches object and the format_spec is non-empty, or if either the format_spec or the return value are not strings.

버전 3.4에서 변경: object().__format__(format_spec) 은 format_spec 이 빈 문자열이 아닌 경우 TypeError 를 일으킵니다.

class frozenset(iterable=set())

새 frozenset 객체를 돌려주는데, 선택적으로 iterable 에서 가져온 요소를 포함합니다. frozenset 은 내장 클래스입니다. 이 클래스에 대한 설명서는 frozenset 과 집합 형 — set, frozenset을 보세요.

다른 컨테이너의 경우 set, list, tuple 및 dict 클래스와 collections 모듈을 보세요.

getattr(object, name)

getattr(object, name, default)

Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object’s attributes, the result is the value of that attribute. For example, getattr(x, 'foobar') is equivalent to x.foobar. If the named attribute does not exist, default is returned if provided, otherwise AttributeError is raised. name need not be a Python identifier (see setattr()).

참고

Since private name mangling happens at compilation time, one must manually mangle a private attribute’s (attributes with two leading underscores) name in order to retrieve it with getattr().

globals()

Return the dictionary implementing the current module namespace. For code within functions, this is set when the function is defined and remains the same regardless of where the function is called.

hasattr(object, name)

인자는 객체와 문자열입니다. 문자열이 객체의 속성 중 하나의 이름이면 결과는 True 이고, 그렇지 않으면 False 가 됩니다. (이것은 getattr(object, name) 을 호출하고 AttributeError 를 발생시키는지를 보는 식으로 구현됩니다.)

hash(object)

객체의 해시값을 돌려줍니다 (해시가 있는 경우). 해시값은 정수다. 딕셔너리 조회 중에 딕셔너리 키를 빨리 비교하는 데 사용됩니다. 같다고 비교되는 숫자 값은 같은 해시값을 갖습니다 (1과 1.0의 경우와 같이 형이 다른 경우조차도 그렇습니다).

참고

For objects with custom __hash__() methods, note that hash() truncates the return value based on the bit width of the host machine.

help()

help(request)

내장 도움말 시스템을 호출합니다. (이 함수는 대화형 사용을 위한 것입니다.) 인자가 제공되지 않으면, 인터프리터 콘솔에서 대화형 도움말 시스템이 시작됩니다. 인자가 문자열이면 문자열은 모듈, 함수, 클래스, 메서드, 키워드 또는 설명서 주제의 이름으로 조회되고, 도움말 페이지가 콘솔에 인쇄됩니다. 인자가 다른 종류의 객체면, 객체에 대한 도움말 페이지가 만들어집니다.

Note that if a slash(/) appears in the parameter list of a function when invoking help(), it means that the parameters prior to the slash are positional-only. For more info, see the FAQ entry on positional-only parameters.

이 함수는 site 모듈에 의해 내장 이름 공간에 추가됩니다.

버전 3.4에서 변경: pydoc 과 inspect 의 변경 사항은 콜러블의 시그니처가 이제 더 포괄적이고 일관성이 있음을 의미합니다.

hex(x)

Convert an integer number to a lowercase hexadecimal string prefixed with “0x”. If x is not a Python int object, it has to define an __index__() method that returns an integer. Some examples:

>>> hex(255)
'0xff'
>>> hex(-42)
'-0x2a'

정수를 대문자 또는 소문자 16진수로, 접두사가 있거나 없는 형태로 변환하려면 다음 방법의 하나를 사용할 수 있습니다:

>>> '%#x' % 255, '%x' % 255, '%X' % 255
('0xff', 'ff', 'FF')
>>> format(255, '#x'), format(255, 'x'), format(255, 'X')
('0xff', 'ff', 'FF')
>>> f'{255:#x}', f'{255:x}', f'{255:X}'
('0xff', 'ff', 'FF')

자세한 내용은 format()을 보세요.

16진수 문자열을 진수 16을 사용해서 정수로 변환하려면 int() 도 보세요.

참고

float에 대한 16진수 문자열 표현을 얻으려면, float.hex() 메서드를 사용하세요.

id(object)

객체의 “아이덴티티”를 돌려준다. 이것은 객체의 수명 동안 유일하고 바뀌지 않음이 보장되는 정수입니다. 수명이 겹치지 않는 두 개의 객체는 같은 id() 값을 가질 수 있습니다.

CPython 구현 상세: This is the address of the object in memory.

id 인자로 감사 이벤트(auditing event) builtins.id를 발생시킵니다.

input()

input(prompt)

prompt 인자가 있으면, 끝에 개행 문자를 붙이지 않고 표준 출력에 씁니다. 그런 다음 함수는 입력에서 한 줄을 읽고, 문자열로 변환해서 (줄 끝의 줄 바꿈 문자를 제거한다) 돌려줍니다. EOF를 읽으면 EOFError 를 일으킵니다. 예:

>>> s = input('--> ')
--> Monty Python's Flying Circus
>>> s
"Monty Python's Flying Circus"

readline 모듈이 로드되었다면, input() 은 그것을 사용하여 정교한 줄 편집과 히스토리 기능을 제공합니다.

입력을 읽기 전에 prompt 인자로 감사 이벤트(auditing event) builtins.input을 발생시킵니다.

Raises an auditing event builtins.input/result with the result after successfully reading input.

class int(number=0, /)

class int(string, /, base=10)

Return an integer object constructed from a number or a string, or return 0 if no arguments are given.

Examples:

>>> int(123.45)
123
>>> int('123')
123
>>> int('   -12_345\n')
-12345
>>> int('FACE', 16)
64206
>>> int('0xface', 0)
64206
>>> int('01110011', base=2)
115

If the argument defines __int__(), int(x) returns x.__int__(). If the argument defines __index__(), it returns x.__index__(). For floating-point numbers, this truncates towards zero.

If the argument is not a number or if base is given, then it must be a string, bytes, or bytearray instance representing an integer in radix base. Optionally, the string can be preceded by + or - (with no space in between), have leading zeros, be surrounded by whitespace, and have single underscores interspersed between digits.

A base-n integer string contains digits, each representing a value from 0 to n-1. The values 0–9 can be represented by any Unicode decimal digit. The values 10–35 can be represented by a to z (or A to Z). The default base is 10. The allowed bases are 0 and 2–36. Base-2, -8, and -16 strings can be optionally prefixed with 0b/0B, 0o/0O, or 0x/0X, as with integer literals in code. For base 0, the string is interpreted in a similar way to an integer literal in code, in that the actual base is 2, 8, 10, or 16 as determined by the prefix. Base 0 also disallows leading zeros: int('010', 0) is not legal, while int('010') and int('010', 8) are.

정수 형은 숫자 형 — int, float, complex 에 설명되어 있습니다.

버전 3.4에서 변경: base 가 int 의 인스턴스가 아니고 base 객체가 base.__index__ 메서드를 가지면, 그 진수로 쓸 정수를 얻기 위해 그 메서드를 호출합니다. 예전 버전에서는 base.__index__ 대신에 base.__int__ 가 사용되었습니다.

버전 3.6에서 변경: 코드 리터럴 처럼 숫자를 밑줄로 그룹화할 수 있습니다.

버전 3.7에서 변경: The first parameter is now positional-only.

버전 3.8에서 변경: Falls back to __index__() if __int__() is not defined.

버전 3.11에서 변경: int string inputs and string representations can be limited to help avoid denial of service attacks. A ValueError is raised when the limit is exceeded while converting a string to an int or when converting an int into a string would exceed the limit. See the integer string conversion length limitation documentation.

버전 3.14에서 변경: int() no longer delegates to the __trunc__() method.

isinstance(object, classinfo)

Return True if the object argument is an instance of the classinfo argument, or of a (direct, indirect, or virtual) subclass thereof. If object is not an object of the given type, the function always returns False. If classinfo is a tuple of type objects (or recursively, other such tuples) or a Union Type of multiple types, return True if object is an instance of any of the types. If classinfo is not a type or tuple of types and such tuples, a TypeError exception is raised. TypeError may not be raised for an invalid type if an earlier check succeeds.

버전 3.10에서 변경: classinfo can be a Union Type.

issubclass(class, classinfo)

Return True if class is a subclass (direct, indirect, or virtual) of classinfo. A class is considered a subclass of itself. classinfo may be a tuple of class objects (or recursively, other such tuples) or a Union Type, in which case return True if class is a subclass of any entry in classinfo. In any other case, a TypeError exception is raised.

버전 3.10에서 변경: classinfo can be a Union Type.

iter(object)

iter(object, sentinel)

Return an iterator object. The first argument is interpreted very differently depending on the presence of the second argument. Without a second argument, object must be a collection object which supports the iterable protocol (the __iter__() method), or it must support the sequence protocol (the __getitem__() method with integer arguments starting at 0). If it does not support either of those protocols, TypeError is raised. If the second argument, sentinel, is given, then object must be a callable object. The iterator created in this case will call object with no arguments for each call to its __next__() method; if the value returned is equal to sentinel, StopIteration will be raised, otherwise the value will be returned.

이터레이터 형 도 보세요.

두 번째 형태의 iter() 의 한가지 유용한 응용은 블록 리더를 만드는 것입니다. 예를 들어, 바이너리 데이터베이스 파일에서 파일의 끝까지 고정 폭 블록 읽기입니다:

from functools import partial
with open('mydata.db', 'rb') as f:
    for block in iter(partial(f.read, 64), b''):
        process_block(block)

len(s)

객체의 길이 (항목 수)를 돌려줍니다. 인자는 시퀀스 (문자열, 바이트열, 튜플, 리스트 또는 range 같은) 또는 컬렉션 (딕셔너리, 집합 또는 불변 집합 같은) 일 수 있습니다.

CPython 구현 상세: len은 range(2 ** 100)와 같이 sys.maxsize보다 긴 길이에서 OverflowError를 발생시킵니다.

class list

class list(iterable)

함수이기보다, 리스트 와 시퀀스 형 — list, tuple, range 에 문서화 된 것처럼, list 는 실제로는 가변 시퀀스 형입니다.

locals()

Return a mapping object representing the current local symbol table, with variable names as the keys, and their currently bound references as the values.

At module scope, as well as when using exec() or eval() with a single namespace, this function returns the same namespace as globals().

At class scope, it returns the namespace that will be passed to the metaclass constructor.

When using exec() or eval() with separate local and global arguments, it returns the local namespace passed in to the function call.

In all of the above cases, each call to locals() in a given frame of execution will return the same mapping object. Changes made through the mapping object returned from locals() will be visible as assigned, reassigned, or deleted local variables, and assigning, reassigning, or deleting local variables will immediately affect the contents of the returned mapping object.

In an optimized scope (including functions, generators, and coroutines), each call to locals() instead returns a fresh dictionary containing the current bindings of the function’s local variables and any nonlocal cell references. In this case, name binding changes made via the returned dict are not written back to the corresponding local variables or nonlocal cell references, and assigning, reassigning, or deleting local variables and nonlocal cell references does not affect the contents of previously returned dictionaries.

Calling locals() as part of a comprehension in a function, generator, or coroutine is equivalent to calling it in the containing scope, except that the comprehension’s initialised iteration variables will be included. In other scopes, it behaves as if the comprehension were running as a nested function.

Calling locals() as part of a generator expression is equivalent to calling it in a nested generator function.

버전 3.12에서 변경: The behaviour of locals() in a comprehension has been updated as described in PEP 709 [https://peps.python.org/pep-0709/].

버전 3.13에서 변경: As part of PEP 667 [https://peps.python.org/pep-0667/], the semantics of mutating the mapping objects returned from this function are now defined. The behavior in optimized scopes is now as described above. Aside from being defined, the behaviour in other scopes remains unchanged from previous versions.

map(function, iterable, /, *iterables, strict=False)

Return an iterator that applies function to every item of iterable, yielding the results. If additional iterables arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. If strict is True and one of the iterables is exhausted before the others, a ValueError is raised. For cases where the function inputs are already arranged into argument tuples, see itertools.starmap().

버전 3.14에서 변경: Added the strict parameter.

max(iterable, *, key=None)

max(iterable, *, default, key=None)

max(arg1, arg2, *args, key=None)

iterable 에서 가장 큰 항목이나 두 개 이상의 인자 중 가장 큰 것을 돌려줍니다.

하나의 위치 인자가 제공되면, 그것은 이터러블 이어야 합니다. iterable에서 가장 큰 항목을 돌려줍니다. 두 개 이상의 위치 인자가 제공되면, 위치 인자 중 가장 큰 것을 돌려줍니다.

선택적 키워드-전용 인자가 두 개 있습니다. key 인자는 list.sort() 에 사용되는 것처럼 단일 인자 순서 함수를 지정합니다. default 인자는 제공된 iterable이 비어있는 경우 돌려줄 객체를 지정합니다. iterable이 비어 있고 default 가 제공되지 않으면 ValueError 가 발생합니다.

여러 항목이 최댓값이면, 함수는 처음 만난 항목을 돌려줍니다. 이것은 sorted(iterable, key=keyfunc, reverse=True)[0] 와 heapq.nlargest(1, iterable, key=keyfunc) 같은 다른 정렬 안정성 보존 도구와 일관성을 유지합니다.

버전 3.4에서 변경: Added the default keyword-only parameter.

버전 3.8에서 변경: key는 None 일 수 있습니다.

class memoryview(object)

지정된 인자로부터 만들어진 “메모리 뷰” 객체를 돌려줍니다. 자세한 정보는 메모리 뷰 를 보세요.

min(iterable, *, key=None)

min(iterable, *, default, key=None)

min(arg1, arg2, *args, key=None)

iterable 에서 가장 작은 항목이나 두 개 이상의 인자 중 가장 작은 것을 돌려줍니다.

하나의 위치 인자가 제공되면, 그것은 이터러블 이어야 합니다. iterable에서 가장 작은 항목을 돌려줍니다. 두 개 이상의 위치 인자가 제공되면, 위치 인자 중 가장 작은 것을 돌려줍니다.

선택적 키워드-전용 인자가 두 개 있습니다. key 인자는 list.sort() 에 사용되는 것처럼 단일 인자 순서 함수를 지정합니다. default 인자는 제공된 iterable이 비어있는 경우 돌려줄 객체를 지정합니다. iterable이 비어 있고 default 가 제공되지 않으면 ValueError 가 발생합니다.

여러 항목이 최솟값이면, 함수는 처음 만난 항목을 돌려줍니다. 이것은 sorted(iterable, key=keyfunc)[0] 와 heapq.nsmallest(1, iterable, key=keyfunc) 같은 다른 정렬 안정성 보존 도구와 일관성을 유지합니다.

버전 3.4에서 변경: Added the default keyword-only parameter.

버전 3.8에서 변경: key는 None 일 수 있습니다.

next(iterator)

next(iterator, default)

Retrieve the next item from the iterator by calling its __next__() method. If default is given, it is returned if the iterator is exhausted, otherwise StopIteration is raised.

class object

This is the ultimate base class of all other classes. It has methods that are common to all instances of Python classes. When the constructor is called, it returns a new featureless object. The constructor does not accept any arguments.

참고

object instances do not have __dict__ attributes, so you can’t assign arbitrary attributes to an instance of object.

oct(x)

Convert an integer number to an octal string prefixed with “0o”. The result is a valid Python expression. If x is not a Python int object, it has to define an __index__() method that returns an integer. For example:

>>> oct(8)
'0o10'
>>> oct(-56)
'-0o70'

If you want to convert an integer number to an octal string either with the prefix “0o” or not, you can use either of the following ways.

>>> '%#o' % 10, '%o' % 10
('0o12', '12')
>>> format(10, '#o'), format(10, 'o')
('0o12', '12')
>>> f'{10:#o}', f'{10:o}'
('0o12', '12')

자세한 내용은 format()을 보세요.

open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)

file 을 열고 해당 파일 객체 를 돌려줍니다. 파일을 열 수 없으면, OSError 가 발생합니다. 이 함수를 사용하는 방법에 대한 더 많은 예제는 파일을 읽고 쓰기를 참조하십시오.

file is a path-like object giving the pathname (absolute or relative to the current working directory) of the file to be opened or an integer file descriptor of the file to be wrapped. (If a file descriptor is given, it is closed when the returned I/O object is closed unless closefd is set to False.)

mode is an optional string that specifies the mode in which the file is opened. It defaults to 'r' which means open for reading in text mode. Other common values are 'w' for writing (truncating the file if it already exists), 'x' for exclusive creation, and 'a' for appending (which on some Unix systems, means that all writes append to the end of the file regardless of the current seek position). In text mode, if encoding is not specified the encoding used is platform-dependent: locale.getencoding() is called to get the current locale encoding. (For reading and writing raw bytes use binary mode and leave encoding unspecified.) The available modes are:

문자

의미

'r'

읽기용으로 엽니다 (기본값)

'w'

쓰기용으로 엽니다, 파일을 먼저 자릅니다.

'x'

독점적인 파일 만들기용으로 엽니다, 이미 존재하는 경우에는 실패합니다.

'a'

open for writing, appending to the end of file if it exists

'b'

바이너리 모드

't'

텍스트 모드 (기본값)

'+'

갱신(읽기 및 쓰기)용으로 엽니다

The default mode is 'r' (open for reading text, a synonym of 'rt'). Modes 'w+' and 'w+b' open and truncate the file. Modes 'r+' and 'r+b' open the file with no truncation.

개요 에서 언급했듯이, 파이썬은 바이너리와 텍스트 I/O를 구별합니다. 바이너리 모드 (mode 인자에 'b' 를 포함합니다)로 열린 파일은 내용을 디코딩 없이 bytes 객체로 돌려줍니다. 텍스트 모드 (기본값, 또는 mode 인자에 't' 가 포함될 때)에서는, 파일의 내용이 str로 반환되는데, 바이트열이 플랫폼 의존적인 인코딩이나 주어진 encoding 을 사용해서 먼저 디코드 됩니다.

참고

파이썬은 하위 운영 체제의 텍스트 파일 개념에 의존하지 않습니다. 모든 처리는 파이썬 자체에 의해 수행되므로 플랫폼에 독립적입니다.

buffering is an optional integer used to set the buffering policy. Pass 0 to switch buffering off (only allowed in binary mode), 1 to select line buffering (only usable when writing in text mode), and an integer > 1 to indicate the size in bytes of a fixed-size chunk buffer. Note that specifying a buffer size this way applies for binary buffered I/O, but TextIOWrapper (i.e., files opened with mode='r+') would have another buffering. To disable buffering in TextIOWrapper, consider using the write_through flag for io.TextIOWrapper.reconfigure(). When no buffering argument is given, the default buffering policy works as follows:

Binary files are buffered in fixed-size chunks; the size of the buffer is chosen using a heuristic trying to determine the underlying device’s “block size” and falling back on io.DEFAULT_BUFFER_SIZE. On many systems, the buffer will typically be 4096 or 8192 bytes long.

“대화형” 텍스트 파일 (isatty() 가 True 를 돌려주는 파일)은 줄 버퍼링을 사용합니다. 다른 텍스트 파일은 바이너리 파일에 대해 위에서 설명한 정책을 사용합니다.

encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is platform dependent (whatever locale.getencoding() returns), but any text encoding supported by Python can be used. See the codecs module for the list of supported encodings.

errors 는 인코딩 및 디코딩 에러를 처리하는 방법을 지정하는 선택적 문자열입니다. 바이너리 모드에서는 사용할 수 없습니다. 다양한 표준 에러 처리기가 제공됩니다 (에러 처리기 에 나열됩니다). 하지만, codecs.register_error()로 등록된 에러 처리기 이름 역시 사용할 수 있습니다. 표준 이름은 다음과 같습니다:

'strict' 는 인코딩 에러가 있는 경우 ValueError 예외를 발생시킵니다. 기본값 None 은 같은 효과를 냅니다.

'ignore' 는 에러를 무시합니다. 인코딩 에러를 무시하면 데이터가 손실될 수 있음에 주의하세요.

'replace' 는 잘못된 데이터가 있는 자리에 대체 마커('?' 와 같은)를 삽입합니다.

'surrogateescape' will represent any incorrect bytes as low surrogate code units ranging from U+DC80 to U+DCFF. These surrogate code units will then be turned back into the same bytes when the surrogateescape error handler is used when writing data. This is useful for processing files in an unknown encoding.

'xmlcharrefreplace' is only supported when writing to a file. Characters not supported by the encoding are replaced with the appropriate XML character reference &#nnn;.

'backslashreplace' 는 잘못된 데이터를 파이썬의 역 슬래시 이스케이프 시퀀스로 대체합니다.

'namereplace' (역시 파일에 쓸 때만 지원됩니다)는 지원되지 않는 문자를 \N{...} 이스케이프 시퀀스로 대체합니다.

newline determines how to parse newline characters from the stream. It can be None, '', '\n', '\r', and '\r\n'. It works as follows:

스트림에서 입력을 읽을 때, newline 이 None 이면, 유니버설 줄 넘김 모드가 활성화됩니다. 입력에 있는 줄은 '\n', '\r' 또는 '\r\n' 로 끝날 수 있으며, 호출자에게 돌려주기 전에 모두 '\n' 로 변환됩니다. 그것이 '' 이면, 유니버설 줄 넘김 모드가 활성화되지만, 줄 끝은 변환되지 않은 채로 호출자에게 반환됩니다. 다른 유효한 값이면, 입력 줄은 주어진 문자열로만 끝나며, 줄 끝은 변환되지 않은 채로 호출자에게 돌려줍니다.

스트림에 출력을 쓸 때, newline 이 None 이면, 모든 '\n' 문자는 시스템 기본 줄 구분자인 os.linesep 로 변환됩니다. newline 이 '' 또는 '\n' 이면, 변환이 이루어지지 않습니다. newline 이 다른 유효한 값이면, 쓰이는 모든 '\n' 문자는 주어진 문자열로 변환됩니다.

If closefd is False and a file descriptor rather than a filename was given, the underlying file descriptor will be kept open when the file is closed. If a filename is given closefd must be True (the default); otherwise, an error will be raised.

콜러블을 opener 로 전달하여 커스텀 오프너를 사용할 수 있습니다. 파일 객체를 위한 하위 파일 디스크립터는 opener 를 (file, flags) 로 호출해서 얻습니다. opener 는 열린 파일 디스크립터를 반환해야 합니다 (opener 에 os.open 을 전달하는 것은 None 을 전달하는 것과 비슷한 기능을 수행하게 됩니다).

새로 만들어진 파일은 상속 불가능 합니다.

다음 예는 주어진 디렉터리에 상대적인 파일을 열기 위해 os.open() 함수의 dir_fd 매개변수를 사용합니다:

>>> import os
>>> dir_fd = os.open('somedir', os.O_RDONLY)
>>> def opener(path, flags):
...     return os.open(path, flags, dir_fd=dir_fd)
...
>>> with open('spamspam.txt', 'w', opener=opener) as f:
...     print('This will be written to somedir/spamspam.txt', file=f)
...
>>> os.close(dir_fd)  # don't leak a file descriptor

open() 함수에 의해 반환된 파일 객체 의 형은 모드에 의존합니다. open() 이 텍스트 모드('w', 'r', 'wt', 'rt', 등)로 파일을 여는 데 사용되면, io.TextIOBase 의 서브 클래스를 돌려줍니다 (구체적으로 io.TextIOWrapper). 버퍼링과 함께 바이너리 모드로 파일을 여는 데 사용되는 경우, 반환되는 클래스는 io.BufferedIOBase 의 서브 클래스입니다. 정확한 클래스는 다양합니다: 읽기 바이너리 모드에서는, io.BufferedReader 를 돌려줍니다; 쓰기 바이너리와 덧붙이기 바이너리 모드에서는, io.BufferedWriter 를 돌려주고, 읽기/쓰기 모드에서는, io.BufferedRandom 을 돌려줍니다. 버퍼링을 끄면, 날 스트림, io.RawIOBase 의 서브 클래스, io.FileIO, 을 돌려줍니다.

See also the file handling modules, such as fileinput, io (where open() is declared), os, os.path, tempfile, and shutil.

Raises an auditing event open with arguments path, mode, flags.

mode와 flags 인자는 원래 호출에서 수정되거나 추론되었을 수 있습니다.

버전 3.3에서 변경:

opener 매개변수가 추가되었습니다.

'x' 모드가 추가되었습니다.

IOError 를 일으켜왔습니다. 이제는 OSError 의 별칭입니다.

독점적 파일 만들기 모드('x')로 여는 파일이 이미 존재하면, 이제 FileExistsError 를 일으킵니다.

버전 3.4에서 변경:

파일은 이제 상속 불가능합니다.

버전 3.5에서 변경:

시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 이 함수는 이제 InterruptedError 예외를 일으키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/] 를 보세요).

'namereplace' 오류 처리기가 추가되었습니다.

버전 3.6에서 변경:

os.PathLike 를 구현하는 객체를 받아들이도록 지원이 추가되었습니다.

윈도우에서, 콘솔 버퍼를 열면 io.FileIO 가 아닌 io.RawIOBase 의 서브 클래스가 반환될 수 있습니다.

버전 3.11에서 변경: The 'U' mode has been removed.

ord(c)

하나의 유니코드 문자를 나타내는 문자열이 주어지면 해당 문자의 유니코드 코드 포인트를 나타내는 정수를 돌려줍니다. 예를 들어, ord('a') 는 정수 97 을 반환하고 ord('€') (유로 기호)는 8364 를 반환합니다. 이것은 chr() 의 반대입니다.

pow(base, exp, mod=None)

base 의 exp 거듭제곱을 돌려줍니다; mod 가 있는 경우, base 의 exp 거듭제곱의 모듈로 mod 를 돌려줍니다 (pow(base, exp) % mod 보다 더 빠르게 계산됩니다). 두 개의 인자 형식인 pow(base, exp) 는 거듭제곱 연산자를 사용하는 것과 동등합니다: base**exp.

The arguments must have numeric types. With mixed operand types, the coercion rules for binary arithmetic operators apply. For int operands, the result has the same type as the operands (after coercion) unless the second argument is negative; in that case, all arguments are converted to float and a float result is delivered. For example, pow(10, 2) returns 100, but pow(10, -2) returns 0.01. For a negative base of type int or float and a non-integral exponent, a complex result is delivered. For example, pow(-9, 0.5) returns a value close to 3j. Whereas, for a negative base of type int or float with an integral exponent, a float result is delivered. For example, pow(-9, 2.0) returns 81.0.

int 피연산자 base 및 exp의 경우, mod가 있으면, mod도 정수 형이어야 하고 mod는 0이 아니어야 합니다. mod가 있고 exp가 음수면, base는 mod와 서로 소(relatively prime)여야 합니다. 이 경우, pow(inv_base, -exp, mod)가 반환되며, 여기서 inv_base는 base 모듈로 mod의 역입니다.

다음은 38 모듈로 97의 역을 계산하는 예입니다:

>>> pow(38, -1, mod=97)
23
>>> 23 * 38 % 97 == 1
True

버전 3.8에서 변경: int 피연산자의 경우, pow의 3 인자 형식은 이제 두 번째 인자가 음수가 되는 것을 허용하여, 모듈러 역수를 계산할 수 있게 합니다.

버전 3.8에서 변경: 키워드 인자를 허용합니다. 이전에는, 위치 인자만 지원되었습니다.

print(*objects, sep=' ', end='\n', file=None, flush=False)

Print objects to the text stream file, separated by sep and followed by end. sep, end, file, and flush, if present, must be given as keyword arguments.

모든 비 키워드 인자는 str() 이 하듯이 문자열로 변환된 후 스트림에 쓰이는데, sep 로 구분되고 end 를 뒤에 붙입니다. sep 과 end 는 모두 문자열이어야 합니다; None 일 수도 있는데, 기본값을 사용한다는 뜻입니다. objects 가 주어지지 않으면 print() 는 end 만 씁니다.

file 인자는 write(string) 메서드를 가진 객체여야 합니다; 존재하지 않거나 None 이면, sys.stdout 이 사용됩니다. 인쇄된 인자는 텍스트 문자열로 변환되기 때문에, print() 는 바이너리 모드 파일 객체와 함께 사용할 수 없습니다. 이를 위해서는. 대신 file.write(...) 를 사용합니다.

Output buffering is usually determined by file. However, if flush is true, the stream is forcibly flushed.

버전 3.3에서 변경: flush 키워드 인자가 추가되었습니다.

class property(fget=None, fset=None, fdel=None, doc=None)

프로퍼티 어트리뷰트를 돌려줍니다.

fget 은 어트리뷰트 값을 얻는 함수입니다. fset 은 어트리뷰트 값을 설정하는 함수입니다. fdel 은 어트리뷰트 값을 삭제하는 함수입니다. 그리고 doc 은 어트리뷰트의 독스트링을 만듭니다.

전형적인 사용은 관리되는 어트리뷰트 x 를 정의하는 것입니다:

class C:
    def __init__(self):
        self._x = None

    def getx(self):
        return self._x

    def setx(self, value):
        self._x = value

    def delx(self):
        del self._x

    x = property(getx, setx, delx, "I'm the 'x' property.")

If c is an instance of C, c.x will invoke the getter, c.x = value will invoke the setter, and del c.x the deleter.

주어진 경우, doc 은 프로퍼티 어트리뷰트의 독스트링이 됩니다. 그렇지 않으면, fget 의 독스트링(있는 경우)이 복사됩니다. 이렇게 하면 property() 를 데코레이터 로 사용하여 읽기 전용 프로퍼티를 쉽게 만들 수 있습니다:

class Parrot:
    def __init__(self):
        self._voltage = 100000

    @property
    def voltage(self):
        """Get the current voltage."""
        return self._voltage

The @property decorator turns the voltage() method into a “getter” for a read-only attribute with the same name, and it sets the docstring for voltage to “Get the current voltage.”

@getter

@setter

@deleter

A property object has getter, setter, and deleter methods usable as decorators that create a copy of the property with the corresponding accessor function set to the decorated function. This is best explained with an example:

class C:
    def __init__(self):
        self._x = None

    @property
    def x(self):
        """I'm the 'x' property."""
        return self._x

    @x.setter
    def x(self, value):
        self._x = value

    @x.deleter
    def x(self):
        del self._x

이 코드는 첫 번째 예제와 정확히 동등합니다. 추가적인 함수들에 원래 프로퍼티(이 경우 x)와 같은 이름을 사용해야 합니다.

반환된 프로퍼티 객체는 생성자 인자에 해당하는 fget, fset 및 fdel 어트리뷰트를 가집니다.

버전 3.5에서 변경: 이제 프로퍼티 개체의 독스트링이 쓰기 가능합니다.

__name__

Attribute holding the name of the property. The name of the property can be changed at runtime.

Added in version 3.13.

class range(stop)

class range(start, stop, step=1)

함수라기보다, range 는 실제로는 범위 와 시퀀스 형 — list, tuple, range 에 설명된 대로 불변 시퀀스 형입니다.

repr(object)

Return a string containing a printable representation of an object. For many types, this function makes an attempt to return a string that would yield an object with the same value when passed to eval(); otherwise, the representation is a string enclosed in angle brackets that contains the name of the type of the object together with additional information often including the name and address of the object. A class can control what this function returns for its instances by defining a __repr__() method. If sys.displayhook() is not accessible, this function will raise RuntimeError.

This class has a custom representation that can be evaluated:

class Person:
   def __init__(self, name, age):
      self.name = name
      self.age = age

   def __repr__(self):
      return f"Person('{self.name}', {self.age})"

reversed(seq)

Return a reverse iterator. seq must be an object which has a __reversed__() method or supports the sequence protocol (the __len__() method and the __getitem__() method with integer arguments starting at 0).

round(number, ndigits=None)

number 를 소수점 다음에 ndigits 정밀도로 반올림한 값을 돌려줍니다. ndigits 가 생략되거나 None 이면, 입력에 가장 가까운 정수를 돌려줍니다.

For the built-in types supporting round(), values are rounded to the closest multiple of 10 to the power minus ndigits; if two multiples are equally close, rounding is done toward the even choice (so, for example, both round(0.5) and round(-0.5) are 0, and round(1.5) is 2). Any integer value is valid for ndigits (positive, zero, or negative). The return value is an integer if ndigits is omitted or None. Otherwise, the return value has the same type as number.

일반적인 파이썬 객체 number 의 경우, round 는 number.__round__ 에 위임합니다.

참고

float에 대한 round() 의 동작은 예상과 다를 수 있습니다: 예를 들어, round(2.675, 2) 는 2.68 대신에 2.67 을 제공합니다. 이것은 버그가 아닙니다: 대부분의 십진 소수가 float로 정확히 표현될 수 없다는 사실로부터 오는 결과입니다. 자세한 정보는 Floating-Point Arithmetic: Issues and Limitations 를 보세요.

class set

class set(iterable)

새 set 객체를 돌려줍니다. 선택적으로 iterable 에서 가져온 요소를 갖습니다. set 은 내장 클래스입니다. 이 클래스에 대한 설명서는 set 및 집합 형 — set, frozenset 을 보세요.

다른 컨테이너의 경우 내장 frozenset, list, tuple 및 dict 클래스와 collections 모듈을 보세요.

setattr(object, name, value)

This is the counterpart of getattr(). The arguments are an object, a string, and an arbitrary value. The string may name an existing attribute or a new attribute. The function assigns the value to the attribute, provided the object allows it. For example, setattr(x, 'foobar', 123) is equivalent to x.foobar = 123.

name need not be a Python identifier as defined in 식별자와 키워드 unless the object chooses to enforce that, for example in a custom __getattribute__() or via __slots__. An attribute whose name is not an identifier will not be accessible using the dot notation, but is accessible through getattr() etc..

참고

Since private name mangling happens at compilation time, one must manually mangle a private attribute’s (attributes with two leading underscores) name in order to set it with setattr().

class slice(stop)

class slice(start, stop, step=None)

Return a slice object representing the set of indices specified by range(start, stop, step). The start and step arguments default to None.

start

stop

step

Slice objects have read-only data attributes start, stop, and step which merely return the argument values (or their default). They have no other explicit functionality; however, they are used by NumPy and other third-party packages.

Slice objects are also generated when extended indexing syntax is used. For example: a[start:stop:step] or a[start:stop, i]. See itertools.islice() for an alternate version that returns an iterator.

버전 3.12에서 변경: Slice objects are now hashable (provided start, stop, and step are hashable).

sorted(iterable, /, *, key=None, reverse=False)

iterable 의 항목들로 새 정렬된 리스트를 돌려줍니다.

키워드 인자로만 지정해야 하는 두 개의 선택적 인자가 있습니다.

key 는 하나의 인자를 받는 함수를 지정하는데, iterable의 각 요소들로부터 비교 키를 추출하는 데 사용됩니다 (예를 들어, key = str.lower). 기본값은 None 입니다 (요소를 직접 비교합니다).

reverse 는 논리값입니다. True 로 설정되면, 각 비교가 뒤집힌 것처럼 리스트 요소들이 정렬됩니다.

예전 스타일의 cmp 함수를 key 함수로 변환하려면 functools.cmp_to_key() 를 사용하세요.

내장 sorted() 함수는 안정적(stable)임이 보장됩니다. 정렬은 같다고 비교되는 요소의 상대적 순서를 변경하지 않으면 안정적입니다 — 이는 여러 번 정렬할 때 유용합니다 (예를 들어, 부서별로 정렬한 후에 급여 등급별로 정렬하기).

The sort algorithm uses only < comparisons between items. While defining an __lt__() method will suffice for sorting, PEP 8 [https://peps.python.org/pep-0008/] recommends that all six rich comparisons be implemented. This will help avoid bugs when using the same data with other ordering tools such as max() that rely on a different underlying method. Implementing all six comparisons also helps avoid confusion for mixed type comparisons which can call reflected the __gt__() method.

정렬 예제와 간단한 정렬 자습서는 Sorting Techniques 를 보세요.

@staticmethod

메서드를 정적 메서드로 변환합니다.

정적 메서드는 묵시적인 첫 번째 인자를 받지 않습니다. 정적 메서드를 선언하려면, 이 관용구를 사용하세요:

class C:
    @staticmethod
    def f(arg1, arg2, argN): ...

@staticmethod 형식은 함수 데코레이터 입니다 – 자세한 내용은 함수 정의를 보세요.

A static method can be called either on the class (such as C.f()) or on an instance (such as C().f()). Moreover, the static method descriptor is also callable, so it can be used in the class definition (such as f()).

Static methods in Python are similar to those found in Java or C++. Also, see classmethod() for a variant that is useful for creating alternate class constructors.

모든 데코레이터와 마찬가지로, staticmethod 를 정규 함수로 호출하여 그 결과로 어떤 일을 할 수도 있습니다. 이것은 클래스 바디에서 함수에 대한 참조가 필요하고 인스턴스 메서드로 자동 변환되는 것을 피하고자 할 때 필요합니다. 이 경우 다음 관용구를 사용하세요:

def regular_function():
    ...

class C:
    method = staticmethod(regular_function)

정적 메서드에 대한 더 자세한 정보는, 표준형 계층을 참조하세요.

버전 3.10에서 변경: Static methods now inherit the method attributes (__module__, __name__, __qualname__, __doc__ and __annotations__), have a new __wrapped__ attribute, and are now callable as regular functions.

class str(object='')

class str(object=b'', encoding='utf-8', errors='strict')

object 의 str 버전을 돌려줍니다. 자세한 내용은 str() 을 보세요.

str 은 내장 문자열 클래스 입니다. 문자열에 대한 일반적인 정보는 텍스트 시퀀스 형 — str 를 보세요.

sum(iterable, /, start=0)

start 및 iterable 의 항목들을 왼쪽에서 오른쪽으로 합하고 합계를 돌려줍니다. iterable 의 항목은 일반적으로 숫자며 시작 값은 문자열이 될 수 없습니다.

For some use cases, there are good alternatives to sum(). The preferred, fast way to concatenate a sequence of strings is by calling ''.join(sequence). To add floating-point values with extended precision, see math.fsum(). To concatenate a series of iterables, consider using itertools.chain().

버전 3.8에서 변경: start 매개 변수는 키워드 인자로만 지정될 수 있습니다.

버전 3.12에서 변경: Summation of floats switched to an algorithm that gives higher accuracy and better commutativity on most builds.

버전 3.14에서 변경: Added specialization for summation of complexes, using same algorithm as for summation of floats.

class super

class super(type, object_or_type=None)

메서드 호출을 type 의 부모나 형제 클래스에 위임하는 프락시 객체를 돌려줍니다. 이는 클래스에서 재정의된 상속 된 메서드를 액세스할 때 유용합니다.

The object_or_type determines the method resolution order to be searched. The search starts from the class right after the type.

For example, if __mro__ of object_or_type is D -> B -> C -> A -> object and the value of type is B, then super() searches C -> A -> object.

The __mro__ attribute of the class corresponding to object_or_type lists the method resolution search order used by both getattr() and super(). The attribute is dynamic and can change whenever the inheritance hierarchy is updated.

두 번째 인자가 생략되면, 반환되는 슈퍼 객체는 연결되지 않았습니다(unbound). 두 번째 인자가 객체면, isinstance(obj, type) 는 참이어야 합니다. 두 번째 인자가 형이면, issubclass(type2, type) 는 참이어야 합니다 (이것은 클래스 메서드에 유용합니다).

When called directly within an ordinary method of a class, both arguments may be omitted (“zero-argument super()”). In this case, type will be the enclosing class, and obj will be the first argument of the immediately enclosing function (typically self). (This means that zero-argument super() will not work as expected within nested functions, including generator expressions, which implicitly create nested functions.)

super 에는 두 가지 일반적인 사용 사례가 있습니다. 단일 상속 클래스 계층 구조에서는, super 를 사용하여 명시적으로 이름을 지정하지 않고 부모 클래스를 참조할 수 있으므로, 코드를 더 유지 관리하기 쉽게 만들 수 있습니다. 이 사용은 다른 프로그래밍 언어에서 super 를 쓰는 것과 매우 유사합니다.

The second use case is to support cooperative multiple inheritance in a dynamic execution environment. This use case is unique to Python and is not found in statically compiled languages or languages that only support single inheritance. This makes it possible to implement “diamond diagrams” where multiple base classes implement the same method. Good design dictates that such implementations have the same calling signature in every case (because the order of calls is determined at runtime, because that order adapts to changes in the class hierarchy, and because that order can include sibling classes that are unknown prior to runtime).

두 경우 모두, 일반적인 슈퍼 클래스 호출은 이런 식입니다:

class C(B):
    def method(self, arg):
        super().method(arg)    # This does the same thing as:
                               # super(C, self).method(arg)

메서드 조회 외에, super()는 어트리뷰트 조회에도 작동합니다. 한가지 가능한 사용 사례는 부모나 형제 클래스에 있는 디스크립터를 호출하는 것입니다.

Note that super() is implemented as part of the binding process for explicit dotted attribute lookups such as super().__getitem__(name). It does so by implementing its own __getattribute__() method for searching classes in a predictable order that supports cooperative multiple inheritance. Accordingly, super() is undefined for implicit lookups using statements or operators such as super()[name].

또한, 인자가 없는 형식을 제외하고는, super() 는 메서드 내부에서만 사용하도록 제한되지 않는다는 점에 유의하세요. 두 개의 인자 형식은 인자를 정확하게 지정하고 적절한 참조를 만듭니다. 인자가 없는 형식은 클래스 정의 내에서만 작동하는데, 컴파일러가 정의되고 있는 클래스를 올바르게 가져오고 일반 메서드에서 현재 인스턴스에 액세스하는 데 필요한 세부 정보를 채우기 때문입니다.

super()를 사용하여 협력적 클래스를 설계하는 방법에 대한 실용적인 제안은 super() 사용 안내 [https://rhettinger.wordpress.com/2011/05/26/super-considered-super/] 를 보세요.

버전 3.14에서 변경: super objects are now pickleable and copyable.

class tuple

class tuple(iterable)

함수이기보다, tuple 은 실제로 튜플 과 시퀀스 형 — list, tuple, range 에 문서화 된 것처럼 불변 시퀀스 형입니다.

class type(object)

class type(name, bases, dict, **kwds)

With one argument, return the type of an object. The return value is a type object and generally the same object as returned by object.__class__.

객체의 형을 검사하는 데는 isinstance() 내장 함수가 권장되는데, 서브 클래스를 고려하기 때문입니다.

With three arguments, return a new type object. This is essentially a dynamic form of the class statement. The name string is the class name and becomes the __name__ attribute. The bases tuple contains the base classes and becomes the __bases__ attribute; if empty, object, the ultimate base of all classes, is added. The dict dictionary contains attribute and method definitions for the class body; it may be copied or wrapped before becoming the __dict__ attribute. The following two statements create identical type objects:

>>> class X:
...     a = 1
...
>>> X = type('X', (), dict(a=1))

See also:

Documentation on attributes and methods on classes.

형 객체

세 인자 형식에 제공된 키워드 인자는 클래스 정의의 (metaclass 를 제외한) 키워드와 같은 방식으로 적절한 메타 클래스 장치(일반적으로 __init_subclass__())에 전달됩니다.

클래스 생성 커스터마이제이션 도 보세요.

버전 3.6에서 변경: Subclasses of type which don’t override type.__new__ may no longer use the one-argument form to get the type of an object.

vars()

vars(object)

Return the __dict__ attribute for a module, class, instance, or any other object with a __dict__ attribute.

Objects such as modules and instances have an updateable __dict__ attribute; however, other objects may have write restrictions on their __dict__ attributes (for example, classes use a types.MappingProxyType to prevent direct dictionary updates).

Without an argument, vars() acts like locals().

객체가 지정되었지만 __dict__ 어트리뷰트가 없으면 TypeError 예외가 발생합니다 (예를 들어, 해당 클래스가 __slots__ 어트리뷰트를 정의하면).

버전 3.13에서 변경: The result of calling this function without an argument has been updated as described for the locals() builtin.

zip(*iterables, strict=False)

Iterate over several iterables in parallel, producing tuples with an item from each one.

Example:

>>> for item in zip([1, 2, 3], ['sugar', 'spice', 'everything nice']):
...     print(item)
...
(1, 'sugar')
(2, 'spice')
(3, 'everything nice')

More formally: zip() returns an iterator of tuples, where the i-th tuple contains the i-th element from each of the argument iterables.

Another way to think of zip() is that it turns rows into columns, and columns into rows. This is similar to transposing a matrix [https://en.wikipedia.org/wiki/Transpose].

zip() is lazy: The elements won’t be processed until the iterable is iterated on, e.g. by a for loop or by wrapping in a list.

One thing to consider is that the iterables passed to zip() could have different lengths; sometimes by design, and sometimes because of a bug in the code that prepared these iterables. Python offers three different approaches to dealing with this issue:

By default, zip() stops when the shortest iterable is exhausted. It will ignore the remaining items in the longer iterables, cutting off the result to the length of the shortest iterable:

>>> list(zip(range(3), ['fee', 'fi', 'fo', 'fum']))
[(0, 'fee'), (1, 'fi'), (2, 'fo')]

zip() is often used in cases where the iterables are assumed to be of equal length. In such cases, it’s recommended to use the strict=True option. Its output is the same as regular zip():

>>> list(zip(('a', 'b', 'c'), (1, 2, 3), strict=True))
[('a', 1), ('b', 2), ('c', 3)]

Unlike the default behavior, it raises a ValueError if one iterable is exhausted before the others:

>>> for item in zip(range(3), ['fee', 'fi', 'fo', 'fum'], strict=True):
...     print(item)
...
(0, 'fee')
(1, 'fi')
(2, 'fo')
Traceback (most recent call last):
  ...
ValueError: zip() argument 2 is longer than argument 1

Without the strict=True argument, any bug that results in iterables of different lengths will be silenced, possibly manifesting as a hard-to-find bug in another part of the program.

Shorter iterables can be padded with a constant value to make all the iterables have the same length. This is done by itertools.zip_longest().

Edge cases: With a single iterable argument, zip() returns an iterator of 1-tuples. With no arguments, it returns an empty iterator.

Tips and tricks:

The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n, strict=True). This repeats the same iterator n times so that each output tuple has the result of n calls to the iterator. This has the effect of dividing the input into n-length chunks.

zip()을 * 연산자와 함께 쓰면 리스트를 unzip 할 수 있습니다:

>>> x = [1, 2, 3]
>>> y = [4, 5, 6]
>>> list(zip(x, y))
[(1, 4), (2, 5), (3, 6)]
>>> x2, y2 = zip(*zip(x, y))
>>> x == list(x2) and y == list(y2)
True

버전 3.10에서 변경: Added the strict argument.

__import__(name, globals=None, locals=None, fromlist=(), level=0)

참고

이것은 importlib.import_module() 과 달리 일상적인 파이썬 프로그래밍에서는 필요하지 않은 고급 함수입니다.

이 함수는 import 문에 의해 호출됩니다. import 문의 의미를 변경하기 위해 대체할 수 있습니다 (builtins 모듈을 임포트하고 builtins .__ import__ 에 대입합니다). 그러나 그렇게 하지 말 것을 강하게 권고하는데, 보통 같은 목적을 달성하는데 임포트 훅(PEP 302 [https://peps.python.org/pep-0302/] 를 보세요)을 사용하는 것이 더 간단하고 기본 임포트 구현이 사용될 것이라고 가정하는 코드들과 문제를 일으키지 않기 때문입니다. __import__() 의 직접 사용 역시 피하고 importlib.import_module() 을 사용할 것을 권합니다.

The function imports the module name, potentially using the given globals and locals to determine how to interpret the name in a package context. The fromlist gives the names of objects or submodules that should be imported from the module given by name. The standard implementation does not use its locals argument at all and uses its globals only to determine the package context of the import statement.

level 은 절대 또는 상대 임포트를 사용할지를 지정합니다. 0 (기본값)은 오직 절대 임포트를 수행한다는 것을 의미합니다. 양수 값 level 은 __import__() 를 호출하는 모듈 디렉터리에 상대적으로 검색할 상위 디렉터리들의 개수를 가리킵니다 (자세한 내용은 PEP 328 [https://peps.python.org/pep-0328/]을 보세요).

name 변수가 package.module 형식일 때, 일반적으로 name 에 의해 명명된 모듈이 아니라, 최상위 패키지(첫 번째 점까지의 이름)가 반환됩니다. 그러나 비어 있지 않은 fromlist 인자가 주어지면 name 에 의해 명명된 모듈이 반환됩니다.

예를 들어, 문장 import spam 은 다음 코드를 닮은 바이트 코드를 생성합니다:

spam = __import__('spam', globals(), locals(), [], 0)

문장 import spam.ham 은 이런 호출로 이어집니다:

spam = __import__('spam.ham', globals(), locals(), [], 0)

여기에서 __import__() 가 최상위 모듈을 돌려주는 것에 주목하세요. 이것이 import 문에 의해 이름에 연결되는 객체이기 때문입니다.

반면에, 문장 from spam.ham import eggs, sausage as saus 는 이런 결과를 줍니다:

_temp = __import__('spam.ham', globals(), locals(), ['eggs', 'sausage'], 0)
eggs = _temp.eggs
saus = _temp.sausage

여기서 spam.ham 모듈이 __import__() 에서 반환됩니다. 이 객체로부터, 임포트할 이름들을 가져온 후 해당 이름들로 대입됩니다.

단순히 이름으로 모듈을 임포트 하기 원한다면 (잠재적으로 패키지 내에서), importlib.import_module() 을 사용하세요.

버전 3.3에서 변경: 음수 level 은 더 지원되지 않습니다 (기본값도 0으로 변경합니다).

버전 3.9에서 변경: 명령 줄 옵션 -E나 -I를 사용 중일 때, 환경 변수 PYTHONCASEOK는 이제 무시됩니다.

각주

[1]

파서는 유닉스 스타일의 줄 종료 규칙만 받아들이는 것에 주의하세요. 파일에서 코드를 읽는 경우, 줄 넘김 변환 모드를 사용해서 윈도우나 맥 스타일 줄 넘김을 변환해야 합니다.

내장 상수

작은 개수의 상수가 내장 이름 공간에 있습니다. 그것들은:

False

bool 형의 거짓 값. False 에 대입할 수 없고 SyntaxError 를 일으킵니다.

True

bool 형의 참값. True 에 대입할 수 없고 SyntaxError 를 일으킵니다.

None

An object frequently used to represent the absence of a value, as when default arguments are not passed to a function. Assignments to None are illegal and raise a SyntaxError. None is the sole instance of the NoneType type.

NotImplemented

A special value which should be returned by the binary special methods (e.g. __eq__(), __lt__(), __add__(), __rsub__(), etc.) to indicate that the operation is not implemented with respect to the other type; may be returned by the in-place binary special methods (e.g. __imul__(), __iand__(), etc.) for the same purpose. It should not be evaluated in a boolean context. NotImplemented is the sole instance of the types.NotImplementedType type.

참고

When a binary (or in-place) method returns NotImplemented the interpreter will try the reflected operation on the other type (or some other fallback, depending on the operator). If all attempts return NotImplemented, the interpreter will raise an appropriate exception. Incorrectly returning NotImplemented will result in a misleading error message or the NotImplemented value being returned to Python code.

예는 산술 연산 구현을 보세요.

참고

NotImplementedError and NotImplemented are not interchangeable, even though they have similar names and purposes. See NotImplementedError for details on when to use it.

버전 3.9에서 변경: Evaluating NotImplemented in a boolean context was deprecated.

버전 3.14에서 변경: Evaluating NotImplemented in a boolean context now raises a TypeError. It previously evaluated to True and emitted a DeprecationWarning since Python 3.9.

Ellipsis

The same as the ellipsis literal “...”. Special value used mostly in conjunction with extended slicing syntax for user-defined container data types. Ellipsis is the sole instance of the types.EllipsisType type.

__debug__

이 상수는 파이썬이 -O 옵션으로 시작되지 않았다면 참이 됩니다. assert 문도 볼 필요가 있습니다.

참고

None, False, True 그리고 __debug__ 은 다시 대입할 수 없습니다 (이것들을 대입하면, 설사 어트리뷰트 이름으로 사용해도, SyntaxError 를 일으킵니다). 그래서 이것들은 “진짜” 상수로 간주 될 수 있습니다.

site 모듈에 의해 추가된 상수들

site 모듈(-S 명령행 옵션이 주어진 경우를 제외하고는, 시작할 때 자동으로 임포트 됩니다)은 내장 이름 공간에 여러 상수를 추가합니다. 대화형 인터프리터 셸에 유용하고 프로그램에서 사용해서는 안 됩니다.

quit(code=None)

exit(code=None)

인쇄될 때, “Use quit() or Ctrl-D (i.e. EOF) to exit”과 같은 메시지를 인쇄하고, 호출될 때, 지정된 종료 코드로 SystemExit 를 일으키는 객체.

help

Object that when printed, prints the message “Type help() for interactive help, or help(object) for help about object.”, and when called, acts as described elsewhere.

copyright

credits

인쇄하거나 호출할 때, 각각 저작권 또는 크레딧 텍스트를 인쇄하는 객체입니다.

license

인쇄될 때 “Type license() to see the full license text”와 같은 메시지를 인쇄하고, 호출될 때 전체 라이센스 텍스트를 페이지 생성기와 같은 방식(한 번에 한 화면씩)으로 표시하는 객체입니다.

내장형

다음 섹션에서는 인터프리터에 내장된 표준형에 관해 설명합니다.

기본 내장 유형은 숫자, 시퀀스, 매핑, 클래스, 인스턴스 및 예외입니다.

일부 컬렉션 클래스는 가변입니다. 제자리에서 멤버를 추가, 삭제 또는 재배치하고 특정 항목을 반환하지 않는 메서드는 컬렉션 인스턴스 자체를 반환하지 않고 None 을 반환합니다.

일부 연산들은 여러 객체 형에서 지원됩니다; 특히 사실상 모든 객체를 동등 비교하고, 논리값을 검사하고, (repr() 함수 또는 약간 다른 str() 함수를 사용해서) 문자열로 변환할 수 있습니다. 두 번째 함수는 print() 함수로 객체를 쓸 때 묵시적으로 사용됩니다.

논리값 검사

모든 객체는 논리값을 검사할 수 있는데, if 또는 while 조건 또는 다음에 나오는 논리 연산의 피연산자로 사용될 수 있도록 합니다.

By default, an object is considered true unless its class defines either a __bool__() method that returns False or a __len__() method that returns zero, when called with the object. [1] Here are most of the built-in objects considered false:

constants defined to be false: None and False

모든 숫자 형들의 영: 0, 0.0, 0j, Decimal(0), Fraction(0, 1)

빈 시퀀스와 컬렉션: '', (), [], {}, set(), range(0)

논리값을 돌려주는 연산과 내장 함수는 달리 명시하지 않는 한 항상 거짓의 경우 0 이나 False 를, 참이면 1 이나 True 를 돌려줍니다. (중요한 예외: 논리 연산 or 와 and 는 항상 피연산자 중 하나를 돌려줍니다.)

논리 연산 — and, or, not

이것들은 우선순위에 따라 오름차순으로 정렬된 논리 연산들입니다:

연산

결과

노트

x or y

if x is true, then x, else y

(1)

x and y

x*가 거짓이면 *x, 그렇지 않으면 y

(2)

not x

x 가 거짓이면 True, 그렇지 않으면 False

(3)

노트:

이것은 단락-회로 연산자이므로 첫 번째 인자가 거짓일 때만 두 번째의 값을 구합니다.

이것은 단락-회로 연산자이므로 첫 번째 인자가 참일 때만 두 번째의 값을 구합니다.

not 은 비논리 연산자들보다 낮은 우선순위를 갖습니다. 그래서, not a == b 는 not (a == b) 로 해석되고, a == not b 는 문법 오류입니다.

비교

파이썬에는 8가지 비교 연산이 있습니다. 이들 모두는 같은 우선순위를 가집니다 (논리 연산보다는 높습니다). 비교는 임의로 연결될 수 있습니다; 예를 들어 x < y <= z 는 y 의 값을 한 번만 구한다는 점을 제외하고는 x < y and y <= z 와 동등합니다 (하지만 두 경우 모두 x < y 가 거짓으로 밝혀지면 z 의 값을 구하지 않습니다).

이 표는 비교 연산을 요약합니다:

연산

뜻

<

엄격히 작다

<=

작거나 같다

>

엄격히 크다

>=

크거나 같다

==

같다

!=

같지 않다

is

객체 아이덴티티

is not

부정된 객체 아이덴티티

서로 다른 숫자 형을 제외하고는 서로 다른 형의 객체들은 같다고 비교되지 않습니다. == 연산자는 항상 정의되지만, 일부 객체 형(예를 들어, 클래스 객체)의 경우 is와 동등합니다. <, <=, > 및 >= 연산자는 의미가 있는 경우에만 정의됩니다; 예를 들어, 인자 중 하나가 복소수이면 TypeError 예외가 발생합니다.

Non-identical instances of a class normally compare as non-equal unless the class defines the __eq__() method.

Instances of a class cannot be ordered with respect to other instances of the same class, or other types of object, unless the class defines enough of the methods __lt__(), __le__(), __gt__(), and __ge__() (in general, __lt__() and __eq__() are sufficient, if you want the conventional meanings of the comparison operators).

is 와 is not 연산자의 동작은 사용자 정의할 수 없습니다; 또한 임의의 두 객체에 적용할 수 있으며 예외를 발생시키지 않습니다.

Two more operations with the same syntactic priority, in and not in, are supported by types that are iterable or implement the __contains__() method.

숫자 형 — int, float, complex

There are three distinct numeric types: integers, floating-point numbers, and complex numbers. In addition, Booleans are a subtype of integers. Integers have unlimited precision. Floating-point numbers are usually implemented using double in C; information about the precision and internal representation of floating-point numbers for the machine on which your program is running is available in sys.float_info. Complex numbers have a real and imaginary part, which are each a floating-point number. To extract these parts from a complex number z, use z.real and z.imag. (The standard library includes the additional numeric types fractions.Fraction, for rationals, and decimal.Decimal, for floating-point numbers with user-definable precision.)

Numbers are created by numeric literals or as the result of built-in functions and operators. Unadorned integer literals (including hex, octal and binary numbers) yield integers. Numeric literals containing a decimal point or an exponent sign yield floating-point numbers. Appending 'j' or 'J' to a numeric literal yields an imaginary number (a complex number with a zero real part) which you can add to an integer or float to get a complex number with real and imaginary parts.

생성자 int(), float(), complex()를 특정 형의 숫자를 만드는데 사용할 수 있습니다.

Python fully supports mixed arithmetic: when a binary arithmetic operator has operands of different numeric types, the operand with the “narrower” type is widened to that of the other, where integer is narrower than floating point. Arithmetic with complex and real operands is defined by the usual mathematical formula, for example:

x + complex(u, v) = complex(x + u, v)
x * complex(u, v) = complex(x * u, x * v)

A comparison between numbers of different types behaves as though the exact values of those numbers were being compared. [2]

(복소수를 제외한) 모든 숫자 형은 다음과 같은 연산들을 지원합니다 (연산의 우선순위는 연산자 우선순위를 참조하십시오):

연산

결과

노트

전체 문서

x + y

x 와 y 의 합

x - y

x 와 y 의 차

x * y

x 와 y 의 곱

x / y

x 와 y 의 몫

x // y

x 와 y 의 정수로 내림한 몫

(1)(2)

x % y

x / y 의 나머지

(2)

-x

음의 x

+x

x 그대로

abs(x)

x 의 절댓값 또는 크기

abs()

int(x)

정수로 변환된 x

(3)(6)

int()

float(x)

실수로 변환된 x

(4)(6)

float()

complex(re, im)

실수부 re 와 허수부 im 으로 구성된 복소수. im 의 기본값은 0입니다.

(6)

complex()

c.conjugate()

복소수 c 의 켤레

divmod(x, y)

쌍 (x // y, x % y)

(2)

divmod()

pow(x, y)

x 의 y 거듭제곱

(5)

pow()

x ** y

x 의 y 거듭제곱

(5)

노트:

Also referred to as integer division. For operands of type int, the result has type int. For operands of type float, the result has type float. In general, the result is a whole integer, though the result’s type is not necessarily int. The result is always rounded towards minus infinity: 1//2 is 0, (-1)//2 is -1, 1//(-2) is -1, and (-1)//(-2) is 0.

복소수에는 사용할 수 없습니다. 적절한 경우 abs()를 사용하여 실수로 변환하십시오.

Conversion from float to int truncates, discarding the fractional part. See functions math.floor() and math.ceil() for alternative conversions.

float는 또한 숫자가 아님(NaN)과 양 또는 음의 무한대를 나타내는 문자열 “nan”과 접두사 “+” 나 “-” 가 선택적으로 붙을 수 있는 “inf”를 받아들입니다.

파이썬은 프로그래밍 언어들에서 흔히 그렇듯이, 있는 것처럼 pow(0, 0) 와 0 ** 0 이 1 이 되도록 정의합니다.

받아들여지는 숫자 리터럴은 0 에서 9 까지 또는 모든 동등한 유니코드들을 (Nd 속성을 가진 코드 포인트들) 포함합니다.

See the Unicode Standard [https://unicode.org/Public/UNIDATA/extracted/DerivedNumericType.txt] for a complete list of code points with the Nd property.

모든 numbers.Real 형 (int 와 float) 은 또한 다음과 같은 연산들을 포함합니다:

연산

결과

math.trunc(x)

x 는 Integral 로 잘립니다

round(x[, n])

x 를 n 자리로 반올림하는데, 절반 값은 짝수로 반올림합니다. n 을 생략하면 기본값은 0입니다.

math.floor(x)

가장 큰 Integral <= x

math.ceil(x)

가장 작은 Integral >= x

추가적인 숫자 연산은 math와 cmath 모듈을 보십시오.

정수 형에 대한 비트 연산

비트 연산은 정수에 대해서만 의미가 있습니다. 비트 연산의 결과는 무한한 부호 비트를 갖는 2의 보수로 수행되는 것처럼 계산됩니다.

이진 비트 연산의 우선순위는 모두 숫자 연산보다 낮고 비교보다 높습니다; 일항 연산 ~ 은 다른 일항 연산들 (+ 와 -) 과 같은 우선순위를 가집니다.

이 표는 비트 연산을 나열하는데, 우선순위에 따라 오름차순으로 정렬되어 있습니다:

연산

결과

노트

x | y

x 와 y 의 비트별 or

(4)

x ^ y

x 와 y 의 비트별 배타적 or (exclusive or)

(4)

x & y

x 와 y 의 비트별 and

(4)

x << n

x 를 n 비트만큼 왼쪽으로 시프트

(1)(2)

x >> n

x 를 n 비트만큼 오른쪽으로 시프트

(1)(3)

~x

x 의 비트 반전

노트:

음의 시프트 수는 허락되지 않고 ValueError 를 일으킵니다.

n 비트만큼의 왼쪽 시프트는 pow(2, n) 를 곱하는 것과 동등합니다.

n 비트만큼 오른쪽으로 시프트 하는 것은 pow(2, n) 로 정수 나눗셈(floor division)하는 것과 동등합니다.

무한한 부호 비트가 있는 것과 같은 결과를 얻으려면, 유한한 2의 보수 표현으로 적어도 하나의 추가적인 부호 확장 비트를 사용하여 (1 + max(x.bit_length(), y.bit_length()) 이상의 작업 비트 폭) 이러한 계산을 수행하는 것으로 충분합니다.

정수 형에 대한 추가 메서드

int 형은 numbers.Integral 추상 베이스 클래스 를 구현합니다. 또한, 몇 가지 메서드를 더 제공합니다:

int.bit_length()

부호와 선행 0을 제외하고, 이진수로 정수를 나타내는 데 필요한 비트 수를 돌려줍니다:

>>> n = -37
>>> bin(n)
'-0b100101'
>>> n.bit_length()
6

좀 더 정확하게 말하자면, x 가 0이 아니면, x.bit_length() 는 2**(k-1) <= abs(x) < 2**k 를 만족하는 유일한 양의 정수 k 입니다. 동등하게, abs(x) 가 정확하게 반올림된 로그값을 가질 만큼 아주 작으면, k = 1 + int(log(abs(x), 2)) 가 됩니다. x 가 0이면, x.bit_length() 는 0 을 돌려줍니다.

다음 코드와 동등합니다:

def bit_length(self):
    s = bin(self)       # binary representation:  bin(-37) --> '-0b100101'
    s = s.lstrip('-0b') # remove leading zeros and minus sign
    return len(s)       # len('100101') --> 6

Added in version 3.1.

int.bit_count()

Return the number of ones in the binary representation of the absolute value of the integer. This is also known as the population count. Example:

>>> n = 19
>>> bin(n)
'0b10011'
>>> n.bit_count()
3
>>> (-n).bit_count()
3

다음 코드와 동등합니다:

def bit_count(self):
    return bin(self).count("1")

Added in version 3.10.

int.to_bytes(length=1, byteorder='big', *, signed=False)

정수를 나타내는 바이트의 배열을 돌려줍니다.

>>> (1024).to_bytes(2, byteorder='big')
b'\x04\x00'
>>> (1024).to_bytes(10, byteorder='big')
b'\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00'
>>> (-1024).to_bytes(10, byteorder='big', signed=True)
b'\xff\xff\xff\xff\xff\xff\xff\xff\xfc\x00'
>>> x = 1000
>>> x.to_bytes((x.bit_length() + 7) // 8, byteorder='little')
b'\xe8\x03'

The integer is represented using length bytes, and defaults to 1. An OverflowError is raised if the integer is not representable with the given number of bytes.

The byteorder argument determines the byte order used to represent the integer, and defaults to "big". If byteorder is "big", the most significant byte is at the beginning of the byte array. If byteorder is "little", the most significant byte is at the end of the byte array.

signed 인자는 정수를 표현하는데 2의 보수가 사용되는지를 결정합니다. signed 가 False 이고 음의 정수가 주어지면, OverflowError 가 일어납니다. signed 의 기본값은 False 입니다.

The default values can be used to conveniently turn an integer into a single byte object:

>>> (65).to_bytes()
b'A'

However, when using the default arguments, don’t try to convert a value greater than 255 or you’ll get an OverflowError.

다음 코드와 동등합니다:

def to_bytes(n, length=1, byteorder='big', signed=False):
    if byteorder == 'little':
        order = range(length)
    elif byteorder == 'big':
        order = reversed(range(length))
    else:
        raise ValueError("byteorder must be either 'little' or 'big'")

    return bytes((n >> i*8) & 0xff for i in order)

Added in version 3.2.

버전 3.11에서 변경: Added default argument values for length and byteorder.

classmethod int.from_bytes(bytes, byteorder='big', *, signed=False)

주어진 바이트 배열로 표현되는 정수를 돌려줍니다.

>>> int.from_bytes(b'\x00\x10', byteorder='big')
16
>>> int.from_bytes(b'\x00\x10', byteorder='little')
4096
>>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=True)
-1024
>>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=False)
64512
>>> int.from_bytes([255, 0, 0], byteorder='big')
16711680

인자 bytes 는 바이트열류 객체 이거나 바이트를 생성하는 이터러블이어야 합니다.

The byteorder argument determines the byte order used to represent the integer, and defaults to "big". If byteorder is "big", the most significant byte is at the beginning of the byte array. If byteorder is "little", the most significant byte is at the end of the byte array. To request the native byte order of the host system, use sys.byteorder as the byte order value.

signed 인자는 정수를 표현하는데 2의 보수가 사용되는지를 나타냅니다.

다음 코드와 동등합니다:

def from_bytes(bytes, byteorder='big', signed=False):
    if byteorder == 'little':
        little_ordered = list(bytes)
    elif byteorder == 'big':
        little_ordered = list(reversed(bytes))
    else:
        raise ValueError("byteorder must be either 'little' or 'big'")

    n = sum(b << i*8 for i, b in enumerate(little_ordered))
    if signed and little_ordered and (little_ordered[-1] & 0x80):
        n -= 1 << 8*len(little_ordered)

    return n

Added in version 3.2.

버전 3.11에서 변경: Added default argument value for byteorder.

int.as_integer_ratio()

Return a pair of integers whose ratio is equal to the original integer and has a positive denominator. The integer ratio of integers (whole numbers) is always the integer as the numerator and 1 as the denominator.

Added in version 3.8.

int.is_integer()

Returns True. Exists for duck type compatibility with float.is_integer().

Added in version 3.12.

실수에 대한 추가 메서드

float 형은 numbers.Real 추상 베이스 클래스 를 구현합니다. 또한, float는 다음과 같은 추가 메서드를 갖습니다.

classmethod float.from_number(x)

Class method to return a floating-point number constructed from a number x.

If the argument is an integer or a floating-point number, a floating-point number with the same value (within Python’s floating-point precision) is returned. If the argument is outside the range of a Python float, an OverflowError will be raised.

For a general Python object x, float.from_number(x) delegates to x.__float__(). If __float__() is not defined then it falls back to __index__().

Added in version 3.14.

float.as_integer_ratio()

Return a pair of integers whose ratio is exactly equal to the original float. The ratio is in lowest terms and has a positive denominator. Raises OverflowError on infinities and a ValueError on NaNs.

float.is_integer()

float 인스턴스가 정숫값을 가진 유한이면 True 를, 그렇지 않으면 False 를 돌려줍니다:

>>> (-2.0).is_integer()
True
>>> (3.2).is_integer()
False

두 가지 메서드가 16진수 문자열과의 변환을 지원합니다. 파이썬의 float는 내부적으로 이진수로 저장되기 때문에 float를 십진수 문자열로 또는 그 반대로 변환하는 것은 보통 반올림 오류를 수반합니다. 이에 반해, 16진수 문자열은 부동 소수점 숫자의 정확한 표현과 지정을 가능하게 합니다. 이것은 디버깅 및 수치 작업에 유용할 수 있습니다.

float.hex()

부동 소수점의 16진수 문자열 표현을 돌려줍니다. 유한 부동 소수점의 경우, 이 표현은 항상 선행하는 0x 와 후행하는 p 와 지수를 포함합니다.

classmethod float.fromhex(s)

16진수 문자열 s 로 표현되는 float를 돌려주는 클래스 메서드. 문자열 s 는 앞뒤 공백을 가질 수 있습니다.

float.hex() 는 인스턴스 메서드인 반면, float.fromhex() 는 클래스 메서드임에 주의하세요.

16진수 문자열은 다음과 같은 형식을 취합니다:

[sign] ['0x'] integer ['.' fraction] ['p' exponent]

선택적인 sign 은 + 나 - 가 될 수 있고, integer 와 fraction 은 16진수 문자열이고, exponent 는 선택적인 선행 부호가 붙을 수 있는 십진수입니다. 대소 문자는 중요하지 않으며 integer 나 fraction 중 어느 하나에 적어도 하나의 16진수가 있어야 합니다. 이 문법은 C99 표준의 6.4.4.2 절에 지정된 문법과 비슷하며, 자바 1.5 이상에서 사용되는 문법과도 비슷합니다. 특히, float.hex() 의 출력은 C 또는 자바 코드에서 16진수의 부동 소수점 리터럴로 사용할 수 있으며, C의 %a 포맷 문자나 자바의 Double.toHexString 가 만들어내는 16진수 문자열은 float.fromhex() 가 받아들입니다.

지수는 16진수가 아닌 십진수로 쓰이고, 숫자에 곱해지는 2의 거듭제곱을 제공한다는 점에 유의하십시오. 예를 들어, 16진수 문자열 0x3.a7p10 는 부동 소수점 숫자 (3 + 10./16 + 7./16**2) * 2.0**10 또는 3740.0 를 나타냅니다:

>>> float.fromhex('0x3.a7p10')
3740.0

3740.0 에 역변환을 적용하면 같은 숫자를 나타내는 다른 16진수 문자열을 얻을 수 있습니다:

>>> float.hex(3740.0)
'0x1.d380000000000p+11'

Additional Methods on Complex

The complex type implements the numbers.Complex abstract base class. complex also has the following additional methods.

classmethod complex.from_number(x)

Class method to convert a number to a complex number.

For a general Python object x, complex.from_number(x) delegates to x.__complex__(). If __complex__() is not defined then it falls back to __float__(). If __float__() is not defined then it falls back to __index__().

Added in version 3.14.

숫자 형의 해싱

For numbers x and y, possibly of different types, it’s a requirement that hash(x) == hash(y) whenever x == y (see the __hash__() method documentation for more details). For ease of implementation and efficiency across a variety of numeric types (including int, float, decimal.Decimal and fractions.Fraction) Python’s hash for numeric types is based on a single mathematical function that’s defined for any rational number, and hence applies to all instances of int and fractions.Fraction, and all finite instances of float and decimal.Decimal. Essentially, this function is given by reduction modulo P for a fixed prime P. The value of P is made available to Python as the modulus attribute of sys.hash_info.

CPython 구현 상세: 현재, 사용되는 소수는 32-비트 C long을 가진 기계에서는 P = 2**31 - 1 이고, 64-비트 C long을 가진 기계에서는 P = 2**61 - 1 입니다.

다음은 규칙에 대한 세부 사항입니다:

x = m / n 이 음이 아닌 유리수이고 n 이 P 로 나뉘지 않는다면, hash(x) 를 m * invmod(n, P) % P 로 정의합니다. 여기서 invmod(n, P) 는 n 의 모듈로 P 역수를 줍니다.

x = m / n 이 음이 아닌 유리수이고 n 이 P 나뉘면 (하지만 m 은 나뉘지 않으면) n 은 모듈로 P 역수를 가지지 않고 위의 규칙은 적용되지 않습니다; 이 경우 hash(x) 를 상숫값 sys.hash_info.inf 로 정의합니다.

x = m / n 이 음의 유리수이면 hash(x) 를 -hash(-x) 로 정의합니다. 얻어진 해시가 -1 이면 -2 로 바꿉니다.

The particular values sys.hash_info.inf and -sys.hash_info.inf are used as hash values for positive infinity or negative infinity (respectively).

복소수(complex) z 의 경우, hash(z.real) + sys.hash_info.imag * hash(z.imag) 를 계산하여 실수부와 허수부의 해시값을 결합하는데, 2**sys.hash_info.width 의 모듈로로 환원해서 range(-2**(sys.hash_info.width - 1), 2**(sys.hash_info.width - 1)) 범위에 들어가도록 만듭니다. 다시 한번, 결과가 -1 이라면 -2 로 바꿉니다.

위의 규칙을 명확히 하기 위해, 여기에 유리수, float, complex 의 해시를 계산하는, 내장 해시와 동등한, 파이썬 코드를 예시합니다:

import sys, math

def hash_fraction(m, n):
    """Compute the hash of a rational number m / n.

    Assumes m and n are integers, with n positive.
    Equivalent to hash(fractions.Fraction(m, n)).

    """
    P = sys.hash_info.modulus
    # Remove common factors of P.  (Unnecessary if m and n already coprime.)
    while m % P == n % P == 0:
        m, n = m // P, n // P

    if n % P == 0:
        hash_value = sys.hash_info.inf
    else:
        # Fermat's Little Theorem: pow(n, P-1, P) is 1, so
        # pow(n, P-2, P) gives the inverse of n modulo P.
        hash_value = (abs(m) % P) * pow(n, P - 2, P) % P
    if m < 0:
        hash_value = -hash_value
    if hash_value == -1:
        hash_value = -2
    return hash_value

def hash_float(x):
    """Compute the hash of a float x."""

    if math.isnan(x):
        return object.__hash__(x)
    elif math.isinf(x):
        return sys.hash_info.inf if x > 0 else -sys.hash_info.inf
    else:
        return hash_fraction(*x.as_integer_ratio())

def hash_complex(z):
    """Compute the hash of a complex number z."""

    hash_value = hash_float(z.real) + sys.hash_info.imag * hash_float(z.imag)
    # do a signed reduction modulo 2**sys.hash_info.width
    M = 2**(sys.hash_info.width - 1)
    hash_value = (hash_value & (M - 1)) - (hash_value & M)
    if hash_value == -1:
        hash_value = -2
    return hash_value

Boolean Type - bool

Booleans represent truth values. The bool type has exactly two constant instances: True and False.

The built-in function bool() converts any value to a boolean, if the value can be interpreted as a truth value (see section 논리값 검사 above).

For logical operations, use the boolean operators and, or and not. When applying the bitwise operators &, |, ^ to two booleans, they return a bool equivalent to the logical operations “and”, “or”, “xor”. However, the logical operators and, or and != should be preferred over &, | and ^.

버전 3.12부터 폐지됨: The use of the bitwise inversion operator ~ is deprecated and will raise an error in Python 3.16.

bool is a subclass of int (see 숫자 형 — int, float, complex). In many numeric contexts, False and True behave like the integers 0 and 1, respectively. However, relying on this is discouraged; explicitly convert using int() instead.

이터레이터 형

파이썬은 컨테이너에 대한 이터레이션 개념을 지원합니다. 이것은 두 개의 메서드를 사용해서 구현됩니다; 이것들은 사용자 정의 클래스가 이터레이션을 지원할 수 있도록 하는 데 사용됩니다. 아래에서 더 자세히 설명할 시퀀스는 항상 이터레이션 메서드를 지원합니다.

One method needs to be defined for container objects to provide iterable support:

container.__iter__()

Return an iterator object. The object is required to support the iterator protocol described below. If a container supports different types of iteration, additional methods can be provided to specifically request iterators for those iteration types. (An example of an object supporting multiple forms of iteration would be a tree structure which supports both breadth-first and depth-first traversal.) This method corresponds to the tp_iter slot of the type structure for Python objects in the Python/C API.

이터레이터 객체 자체는 다음과 같은 두 가지 메서드를 지원해야 하는데, 둘이 함께 이터레이터 프로토콜 (iterator protocol) 를 이룹니다.:

iterator.__iter__()

Return the iterator object itself. This is required to allow both containers and iterators to be used with the for and in statements. This method corresponds to the tp_iter slot of the type structure for Python objects in the Python/C API.

iterator.__next__()

Return the next item from the iterator. If there are no further items, raise the StopIteration exception. This method corresponds to the tp_iternext slot of the type structure for Python objects in the Python/C API.

파이썬은 일반적이거나 특정한 시퀀스 형, 딕셔너리, 기타 더 특화된 형태에 대한 이터레이션을 지원하기 위해 여러 이터레이터 객체를 정의합니다. 이터레이터 프로토콜의 구현을 넘어서 개별적인 형이 중요하지는 않습니다.

일단 이터레이터의 __next__() 메서드가 StopIteration 를 일으키면, 그 이후의 호출에 대해서도 같이 동작해야 합니다. 이 속성을 따르지 않는 구현은 망가진 것으로 간주합니다.

제너레이터 형

Python’s generators provide a convenient way to implement the iterator protocol. If a container object’s __iter__() method is implemented as a generator, it will automatically return an iterator object (technically, a generator object) supplying the __iter__() and __next__() methods. More information about generators can be found in the documentation for the yield expression.

시퀀스 형 — list, tuple, range

세 가지 기본 시퀀스 형이 있습니다: 리스트, 튜플, 범위 객체. 바이너리 데이터 와 텍스트 문자열 의 처리를 위해 추가된 시퀀스 형들은 별도의 섹션에서 설명합니다.

공통 시퀀스 연산

다음 표의 연산들은 대부분의 가변과 불변 시퀀스에서 지원됩니다. 사용자 정의 시퀀스에서 이 연산들을 올바르게 구현하기 쉽게 하려고 collections.abc.Sequence ABC가 제공됩니다.

이 표는 우선순위에 따라 오름차순으로 시퀀스 연산들을 나열합니다. 표에서, s 와 t 는 같은 형의 시퀀스고, n, i, j, k 는 정수이고, x 는 s 가 요구하는 형과 값 제한을 만족하는 임의의 객체입니다.

in 과 not in 연산은 비교 연산과 우선순위가 같습니다. + (이어 붙이기)와 * (반복) 연산은 대응하는 숫자 연산과 같은 우선순위를 갖습니다. [3]

연산

결과

노트

x in s

s 의 항목 중 하나가 x 와 같으면 True, 그렇지 않으면 False

(1)

x not in s

s 의 항목 중 하나가 x 와 같으면 False, 그렇지 않으면 True

(1)

s + t

s 와 t 의 이어 붙이기

(6)(7)

s * n 또는 n * s

s 를 그 자신에 n 번 더하는 것과 같습니다

(2)(7)

s[i]

s 의 i 번째 항목, 0에서 시작합니다

(3)

s[i:j]

s 의 i 에서 j 까지의 슬라이스

(3)(4)

s[i:j:k]

s 의 i 에서 j 까지 스텝 k 의 슬라이스

(3)(5)

len(s)

s 의 길이

min(s)

s 의 가장 작은 항목

max(s)

s 의 가장 큰 항목

s.index(x[, i[, j]])

(인덱스 i 또는 그 이후에, 인덱스 j 전에 등장하는) s 의 첫 번째 x 의 인덱스

(8)

s.count(x)

s 등장하는 x 의 총수

같은 형의 시퀀스는 비교를 지원합니다. 특히, 튜플과 리스트는 대응하는 항목들을 사전적으로 비교합니다. 이것은 같다고 비교되기 위해서는, 모든 항목이 같다고 비교되고, 두 시퀀스의 형과 길이가 같아야 함을 의미합니다. (자세한 내용은 언어 레퍼런스의 비교를 참조하십시오.)

Forward and reversed iterators over mutable sequences access values using an index. That index will continue to march forward (or backward) even if the underlying sequence is mutated. The iterator terminates only when an IndexError or a StopIteration is encountered (or when the index drops below zero).

노트:

in 과 not in 연산은 일반적으로 단순한 포함 검사를 위해서만 사용되지만, 몇몇 특수한 시퀀스 (str, bytes, bytearray 같은) 들은 서브 시퀀스 검사에 사용하기도 합니다:

>>> "gg" in "eggs"
True

n 의 값이 0 보다 작으면 0 으로 처리됩니다 (s 와 같은 형의 빈 시퀀스가 됩니다). 시퀀스 s 의 항목들이 복사되지 않음에 주의해야 합니다; 그들은 여러 번 참조됩니다. 이것은 종종 새 파이썬 프로그래머들을 괴롭힙니다; 이 코드를 살펴보세요:

>>> lists = [[]] * 3
>>> lists
[[], [], []]
>>> lists[0].append(3)
>>> lists
[[3], [3], [3]]

무슨 일이 일어났는가 하면, [[]] 는 빈 리스트를 포함하는 길이 1인 리스트인데, [[]] * 3 의 세 항목은 모두 같은 빈 리스트를 참조합니다. lists 의 어느 항목을 수정하더라도 이 하나의 리스트를 수정하게 됩니다. 서로 다른 리스트들을 포함하는 리스트는 이런 식으로 만들 수 있습니다:

>>> lists = [[] for i in range(3)]
>>> lists[0].append(3)
>>> lists[1].append(5)
>>> lists[2].append(7)
>>> lists
[[3], [5], [7]]

더 자세한 설명은 FAQ 항목 다차원 리스트를 어떻게 만듭니까?에서 얻을 수 있습니다.

i 또는 j 가 음수인 경우, 인덱스는 시퀀스 s 의 끝에 상대적입니다: len(s) + i 이나 len(s) + j 로 치환됩니다. 하지만 -0 은 여전히 0 입니다.

i 에서 j 까지의 s 의 슬라이스는 i <= k < j 를 만족하는 인덱스 k 의 항목들로 구성된 시퀀스로 정의됩니다. i 또는 j 가 len(s) 보다 크면 len(s) 을 사용합니다. i 가 생략되거나 None 이라면 0 을 사용합니다. j 가 생략되거나 None 이면 len(s) 을 사용합니다. i 가 j 보다 크거나 같으면 빈 슬라이스가 됩니다.

스텝 k 가 있는 i 에서 j 까지의 슬라이스는 0 <= n < (j-i)/k 를 만족하는 인덱스 x = i + n*k 의 항목들로 구성된 시퀀스로 정의됩니다. 다시 말하면, 인덱스는 i, i+k, i+2*k, i+3*k 등이며 j 에 도달할 때 멈춥니다 (하지만 절대 j 를 포함하지는 않습니다). k 가 양수면 i 와 j 는 더 큰 경우 len(s) 로 줄어듭니다. k 가 음수면, i 와 j 는 더 큰 경우 len(s) - 1 로 줄어듭니다. i 또는 j 가 생략되거나 None 이면, 그것들은 “끝” 값이 됩니다 (끝은 k 의 부호에 따라 달라집니다). k 는 0일 수 없음에 주의하세요. k 가 None 이면 1 로 취급됩니다.

불변 시퀀스를 이어 붙이면 항상 새로운 객체가 생성됩니다. 이것은 반복적으로 이어붙이기를 해서 시퀀스를 만들 때 실행 시간이 시퀀스의 총 길이의 제곱에 비례한다는 뜻입니다. 선형 실행 시간 비용을 얻으려면 아래 대안 중 하나로 전환해야 합니다:

str 객체를 이어붙이기를 한다면, 리스트를 만들고 마지막에 str.join() 을 사용하거나 io.StringIO 인스턴스에 쓰고 완료될 때 값을 꺼낼 수 있습니다

bytes 객체를 연결하는 경우 비슷하게 bytes.join() 또는 io.BytesIO 를 사용하거나, bytearray 객체를 사용하여 제자리에서 이어붙이기를 할 수 있습니다. bytearray 객체는 가변이고 효율적인 과할당(overallocation) 메커니즘을 가지고 있습니다.

tuple 객체를 이어붙이기를 한다면, 대신 list를 extend 하십시오.

다른 형의 경우 관련 클래스 문서를 조사하십시오.

일부 시퀀스 형 (예를 들어 range)은 특정 패턴을 따르는 항목 시퀀스 만 지원하기 때문에 시퀀스 이어붙이기나 반복을 지원하지 않습니다.

s 에 x 가 없을 때 index 는 ValueError 를 일으킵니다. 모든 구현이 추가 인자 i 및 j 전달을 지원하지는 않습니다. 이러한 인자를 사용하면 시퀀스의 부분을 효율적으로 검색할 수 있습니다. 추가 인자를 전달하는 것은 대략 s[i:j].index(x) 를 사용하는 것과 비슷한데, 데이터를 복사하지 않고 반환된 인덱스가 슬라이스의 시작이 아닌 시퀀스의 시작을 기준으로 삼습니다.

불변 시퀀스 형

불변 시퀀스 형이 일반적으로 구현하지만, 가변 시퀀스 형에서는 구현되지 않는 연산은 내장 hash() 에 대한 지원입니다.

이 지원은 tuple 인스턴스와 같은 불변 시퀀스를 dict 키로 사용하고 set 및 frozenset 인스턴스에 저장할 수 있도록 합니다.

해시 불가능 값을 포함하는 불변 시퀀스를 해시 하려고 하면 TypeError 를 일으킵니다.

가변 시퀀스 형

다음 표의 연산들은 가변 시퀀스 형에 정의되어 있습니다. 사용자 정의 시퀀스에서 이 연산들을 올바르게 구현하기 쉽게 하려고 collections.abc.MutableSequence ABC가 제공됩니다.

표에서 s 는 가변 시퀀스 형의 인스턴스이고, t 는 임의의 이터러블 객체이며, x 는 s 가 요구하는 형 및 값 제한을 충족시키는 임의의 객체입니다 (예를 들어, bytearray 는 값 제한 0 <= x <= 255 를 만족하는 정수만 받아들입니다.

연산

결과

노트

s[i] = x

s 의 항목 i 를 x 로 대체합니다

s[i:j] = t

i 에서 j 까지의 s 슬라이스가 이터러블 t 의 내용으로 대체됩니다

del s[i:j]

s[i:j] = [] 와 같습니다

s[i:j:k] = t

s[i:j:k] 의 항목들이 t 의 항목들로 대체됩니다

(1)

del s[i:j:k]

리스트에서 s[i:j:k] 의 항목들을 제거합니다

s.append(x)

시퀀스의 끝에 x 를 추가합니다 (s[len(s):len(s)] = [x] 와 같습니다)

s.clear()

s 에서 모든 항목을 제거합니다 (del s[:] 와 같습니다)

(5)

s.copy()

s 의 얕은 복사본을 만듭니다 (s[:] 와 같습니다)

(5)

s.extend(t) 또는 s += t

t 의 내용으로 s 를 확장합니다 (대부분 s[len(s):len(s)] = t 와 같습니다)

s *= n

내용이 n 번 반복되도록 s 를 갱신합니다

(6)

s.insert(i, x)

x 를 s 의 i 로 주어진 인덱스에 삽입합니다 (s[i:i] = [x] 와 같습니다)

s.pop() or s.pop(i)

i 에 있는 항목을 꺼냄과 동시에 s 에서 제거합니다

(2)

s.remove(x)

removes the first item from s where s[i] is equal to x

(3)

s.reverse()

제자리에서 s 의 항목들의 순서를 뒤집습니다

(4)

노트:

If k is not equal to 1, t must have the same length as the slice it is replacing.

선택적 인자 i 의 기본값은 -1 입니다. 그래서 기본적으로 마지막 항목이 제거되면서 반환됩니다.

x 가 s 에서 발견되지 않으면 remove() 는 ValueError 를 일으킵니다.

큰 시퀀스를 뒤집을 때 공간 절약을 위해 reverse() 메서드는 제자리에서 시퀀스를 수정합니다. 부작용으로 작동한다는 것을 사용자에게 상기시키기 위해 뒤집힌 시퀀스를 돌려주지 않습니다.

clear()와 copy() 는 슬라이싱 연산을 지원하지 않는 (dict 와 set 같은) 가변 컨테이너들의 인터페이스와 일관성을 유지하기 위해 포함됩니다. copy()는 collections.abc.MutableSequence ABC 일부가 아니지만, 대부분 구상 가변 시퀀스 클래스는 이것을 제공합니다.

Added in version 3.3: clear()와 copy() 메서드.

n 값은 정수이거나, __index__() 를 구현하는 객체입니다. n 이 0 이거나 음수면 시퀀스를 지웁니다. 시퀀스의 항목들은 복사되지 않습니다; 공통 시퀀스 연산에서 s * n 를 위해 설명한 것처럼 여러 번 참조됩니다.

리스트

리스트는 가변 시퀀스로, 일반적으로 등질 항목들의 모음을 저장하는 데 사용됩니다 (정확한 유사도는 응용 프로그램마다 다를 수 있습니다).

class list([iterable])

리스트는 여러 가지 방법으로 만들 수 있습니다:

대괄호를 사용하여 빈 리스트를 표시하기: []

대괄호를 사용하여 쉼표로 항목 구분하기: [a], [a, b, c]

리스트 컴프리헨션 사용하기: [x for x in iterable]

형 생성자를 사용하기: list() 또는 list(iterable)

생성자는 항목들과 그 순서가 iterable 과 같은 리스트를 만듭니다. iterable 은 시퀀스, 이터레이션을 지원하는 컨테이너, 이터레이터 객체가 될 수 있습니다. iterable 이 이미 리스트라면, iterable[:] 과 비슷하게 복사본을 만들어서 반환합니다. 예를 들어, list('abc') 는 ['a', 'b', 'c'] 를 반환하고 list( (1, 2, 3) ) 는 [1, 2, 3] 를 반환합니다. 인자가 주어지지 않으면, 생성자는 새로운 빈 리스트인 [] 을 만듭니다.

다른 많은 연산도 리스트를 만드는데, 내장 sorted() 도 그런 것 중 하나다.

리스트는 공통 과 가변 시퀀스 연산들을 모두 구현합니다. 또한, 리스트는 다음과 같은 추가 메서드를 제공합니다:

sort(*, key=None, reverse=False)

이 메서드는 항목 간의 < 비교만 사용하여 리스트를 제자리에서 정렬합니다. 예외는 억제되지 않습니다 - 비교 연산이 실패하면 전체 정렬 연산이 실패합니다 (리스트는 부분적으로 수정된 상태로 남아있게 됩니다).

sort() 는 키워드로만 전달할 수 있는 두 개의 인자를 받아들입니다 (키워드-전용 인자):

key 는 인자 하나를 받아들이는 함수를 지정하는데, 각 리스트 요소에서 비교 키를 추출하는 데 사용됩니다 (예를 들어, key=str.lower). 리스트의 각 항목에 해당하는 키는 한 번만 계산된 후 전체 정렬 프로세스에 사용됩니다. 기본값 None 은 리스트 항목들이 별도의 키값을 계산하지 않고 직접 정렬된다는 것을 의미합니다.

functools.cmp_to_key() 유틸리티는 2.x 스타일 cmp 함수를 key 함수로 변환하는 데 사용할 수 있습니다.

reverse 는 논리값입니다. True 로 설정되면, 각 비교가 역전된 것처럼 리스트 요소들이 정렬됩니다.

이 메서드는 큰 시퀀스를 정렬할 때 공간 절약을 위해 시퀀스를 제자리에서 수정합니다. 부작용으로 작동한다는 것을 사용자에게 상기시키기 위해 정렬된 시퀀스를 돌려주지 않습니다 (새 정렬 된 리스트 인스턴스를 명시적으로 요청하려면 sorted()를 사용하십시오).

sort() 메서드는 안정적임이 보장됩니다. 정렬은 같다고 비교되는 요소들의 상대적 순서를 변경하지 않으면 안정적입니다 — 이는 여러 번 정렬하는 데 유용합니다 (예를 들어, 부서별로 정렬한 후에 급여 등급으로 정렬).

정렬 예제와 간단한 정렬 자습서는 Sorting Techniques를 참조하십시오.

CPython 구현 상세: 리스트가 정렬되는 동안, 리스트를 변경하려고 할 때의, 또는 관찰하려고 할 때조차, 효과는 정의되지 않습니다. 파이썬의 C 구현은 그동안 리스트를 비어있는 것으로 보이게 하고, 정렬 중에 리스트가 변경되었음을 감지할 수 있다면 ValueError 를 일으킵니다.

튜플

튜플은 불변 시퀀스인데, 보통 이질적인 데이터의 모음을 저장하는 데 사용됩니다 (예를 들어, 내장 enumerate() 가 만드는 2-튜플). 튜플은 등질적인 데이터의 불변 시퀀스가 필요한 경우에도 사용됩니다 (예를 들어, set 이나 dict 인스턴스에 저장하고자 하는 경우).

class tuple([iterable])

튜플은 여러 가지 방법으로 만들 수 있습니다:

괄호를 사용하여 빈 튜플을 나타내기: ()

단일 항목 튜플을 위해 끝에 쉼표를 붙이기: a, 또는 (a,)

항목을 쉼표로 구분하기: a, b, c 또는 (a, b, c)

내장 tuple() 사용하기: tuple() 또는 tuple(iterable)

생성자는 항목들과 그 순서가 iterable 과 같은 튜플을 만듭니다. iterable 은 시퀀스, 이터레이션을 지원하는 컨테이너, 이터레이터 객체가 될 수 있습니다. iterable 이 이미 튜플이라면 변경되지 않은 상태로 반환됩니다. 예를 들어 tuple('abc') 는 ('a', 'b', 'c') 를 반환하고, tuple( [1, 2, 3] ) 는 (1, 2, 3) 을 반환합니다. 인자가 주어지지 않으면, 생성자는 새로운 빈 튜플인 () 을 만듭니다.

튜플을 만드는 것은 실제로는 괄호가 아닌 쉼표임에 유의하십시오. 괄호는 빈 튜플의 경우를 제외하고는 선택적이거나 문법상의 모호함을 피하고자 필요합니다. 예를 들어, f(a, b, c) 는 3개의 인자를 가진 함수 호출이지만, f((a, b, c)) 는 하나의 인자로 3-튜플을 갖는 함수 호출입니다.

튜플은 공통 시퀀스 연산을 모두 구현합니다.

이름에 의한 액세스가 인덱스에 의한 액세스보다 더 명확한 이질적 데이터 컬렉션의 경우, collections.namedtuple() 이 단순한 튜플 객체보다 더 적절한 선택일 수 있습니다.

범위

range 형은 숫자의 불변 시퀀스를 나타내며 for 루프에서 특정 횟수만큼 반복하는 데 흔히 사용됩니다.

class range(stop)

class range(start, stop[, step])

The arguments to the range constructor must be integers (either built-in int or any object that implements the __index__() special method). If the step argument is omitted, it defaults to 1. If the start argument is omitted, it defaults to 0. If step is zero, ValueError is raised.

양수 step 의 경우, 범위 r 의 내용은 식 r[i] = start + step*i 에 의해 결정됩니다. 이때 i >= 0 이고 r[i] < stop 입니다.

음수 step 의 경우, 범위의 내용은 여전히 식 r[i] = start + step*i 에 의해 결정되지만, 제약 조건은 i >= 0 과 r[i] > stop 이 됩니다.

r[0] 제약 조건을 만족시키지 않으면 범위 객체는 비게 됩니다. 범위는 음의 인덱스를 지원하지만, 이는 시퀀스의 끝에서부터 양의 인덱스만큼 떨어진 인덱스로 해석됩니다.

sys.maxsize 보다 큰 절댓값을 포함하는 범위는 허용되지만, (len() 과 같은) 일부 기능은 OverflowError 를 발생시킬 수 있습니다.

범위 예제:

>>> list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(range(1, 11))
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> list(range(0, 30, 5))
[0, 5, 10, 15, 20, 25]
>>> list(range(0, 10, 3))
[0, 3, 6, 9]
>>> list(range(0, -10, -1))
[0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
>>> list(range(0))
[]
>>> list(range(1, 0))
[]

범위는 이어 붙이기와 반복을 제외한 공통 시퀀스 연산을 모두 구현합니다 (범위 객체는 엄격한 패턴을 따르는 시퀀스 만 나타낼 수 있는데 반복과 이어 붙이기는 보통 그 패턴을 위반한다는 사실에 기인합니다).

start

start 매개변수의 값 (또는 매개변수가 제공되지 않으면 0)

stop

stop 매개변수의 값

step

step 매개변수의 값 (또는 매개변수가 제공되지 않으면 1)

정규 list 나 tuple 에 비해 range 형의 장점은 range 객체는 표현하는 범위의 크기에 무관하게 항상 같은 (작은) 양의 메모리를 사용한다는 것입니다 (start, stop, step 값만을 저장하고, 필요에 따라 개별 항목과 하위 범위를 계산하기 때문입니다).

범위 객체는 collections.abc.Sequence ABC를 구현하고, 포함 검사, 요소 인덱스 검색, 슬라이싱, 음수 인덱스 지원과 같은 기능을 제공합니다 (시퀀스 형 — list, tuple, range 를 보세요):

>>> r = range(0, 20, 2)
>>> r
range(0, 20, 2)
>>> 11 in r
False
>>> 10 in r
True
>>> r.index(10)
5
>>> r[5]
10
>>> r[:5]
range(0, 10, 2)
>>> r[-1]
18

== 나 != 로 범위 객체가 같은지 검사하면 시퀀스처럼 비교합니다. 즉, 두 범위 객체가 같은 시퀀스의 값을 나타낼 때 같다고 취급됩니다. (같다고 비교되는 두 개의 범위 객체가 서로 다른 start, stop, step 어트리뷰트를 가질 수 있음에 주의하세요. 예를 들어, range(0) == range(2, 1, 3) 또는 range(0, 3, 2) == range(0, 4, 2).)

버전 3.2에서 변경: 시퀀스 ABC를 구현합니다. int 객체의 포함 검사는 모든 항목을 이터레이트하는 대신 상수 시간으로 수행됩니다.

버전 3.3에서 변경: (객체 아이덴티티에 기반을 두는 대신) 범위 객체가 정의하는 값들의 시퀀스에 기반을 둔 비교를 위해 ‘==’ 와 ‘!=’ 를 정의합니다.

Added the start, stop and step attributes.

더 보기

The linspace recipe [https://code.activestate.com/recipes/579000-equally-spaced-numbers-linspace/] shows how to implement a lazy version of range suitable for floating-point applications.

텍스트 시퀀스 형 — str

파이썬의 텍스트 데이터는 str, 또는 문자열 (strings), 객체를 사용하여 처리됩니다. 문자열은 유니코드 코드 포인트의 불변 시퀀스 입니다. 문자열 리터럴은 다양한 방법으로 작성됩니다:

작은따옴표: '"큰" 따옴표를 담을 수 있습니다'

Double quotes: "allows embedded 'single' quotes"

삼중 따옴표: '''세 개의 작은따옴표''', """세 개의 큰따옴표"""

삼중 따옴표로 묶인 문자열은 여러 줄에 걸쳐있을 수 있습니다 - 연관된 모든 공백이 문자열 리터럴에 포함됩니다.

단일 표현식의 일부이고 그 들 사이에 공백만 있는 문자열 리터럴은 묵시적으로 단일 문자열 리터럴로 변환됩니다. 즉, ("spam " "eggs") == "spam eggs".

See 문자열과 바이트열 리터럴 for more about the various forms of string literal, including supported escape sequences, and the r (“raw”) prefix that disables most escape sequence processing.

문자열은 str 생성자를 사용하여 다른 객체로부터 만들어질 수도 있습니다.

별도의 “문자” 형이 없으므로 문자열을 인덱싱하면 길이가 1인 문자열이 생성됩니다. 즉, 비어 있지 않은 문자열 s 의 경우, s[0] == s[0:1] 입니다.

또한, 가변 문자열형은 없지만, 여러 단편으로부터 문자열을 효율적으로 구성하는데 str.join() 또는 io.StringIO 를 사용할 수 있습니다.

버전 3.3에서 변경: 파이썬 2시리즈와의 하위 호환성을 위해서, u 접두어가 문자열 리터럴에 다시 한번 허용됩니다. 문자열 리터럴의 의미에 영향을 미치지 않으며 r 접두사와 결합 될 수 없습니다.

class str(object='')

class str(object=b'', encoding='utf-8', errors='strict')

object 의 문자열 버전을 돌려줍니다. object 가 제공되지 않으면, 빈 문자열을 돌려줍니다. 그렇지 않으면, str() 의 동작은 encoding 또는 errors 가 주어졌는지에 따라 달라지는데, 다음과 같습니다.

If neither encoding nor errors is given, str(object) returns type(object).__str__(object), which is the “informal” or nicely printable string representation of object. For string objects, this is the string itself. If object does not have a __str__() method, then str() falls back to returning repr(object).

encoding 또는 errors 중 적어도 하나가 주어지면, object 는 bytes-like object (예, bytes 또는 bytearray) 이어야 합니다. 이 경우, object 가 bytes (또는 bytearray) 객체이면, str(bytes, encoding, errors) 는 bytes.decode(encoding, errors) 와 동등합니다. 그 이외의 경우, bytes.decode() 호출 전에 버퍼 객체의 하부 바이트열 객체를 얻습니다. 버퍼 객체에 대한 정보는 바이너리 시퀀스 형 — bytes, bytearray, memoryview와 버퍼 프로토콜 를 보십시오.

encoding 또는 errors 인자 없이 bytes 객체를 str() 에 전달하는 것은 비형식적 문자열 표현을 반환하는 첫 번째 상황에 해당합니다 (파이썬 명령행 옵션 -b 도 보십시오). 예를 들면:

>>> str(b'Zoot!')
"b'Zoot!'"

str 클래스와 그 메서드에 대한 더 자세한 정보는 텍스트 시퀀스 형 — str와 아래의 문자열 메서드 섹션을 보십시오. 포맷된 문자열을 출력하려면 f-strings 및 포맷 문자열 문법 섹션을 참조하십시오. 또한, 텍스트 처리 서비스 섹션을 보십시오.

문자열 메서드

문자열은 공통 시퀀스 연산들을 모두 구현하고, 아래에 기술된 추가적인 메서드도 구현합니다.

문자열은 또한 두 가지 스타일의 문자열 포매팅을 지원합니다. 하나는 큰 폭의 유연성과 사용자 지정을 제공하고 (참조 str.format(), 포맷 문자열 문법, 사용자 지정 문자열 포매팅을 참조하세요) 다른 하나는 C printf 스타일에 기반을 두는데, 더 좁은 범위의 형을 처리하고 올바르게 사용하기는 다소 어렵지만, 처리할 수 있는 경우에는 종종 더 빠릅니다 (printf 스타일 문자열 포매팅).

표준 라이브러리의 텍스트 처리 서비스 섹션은 다양한 텍스트 관련 유틸리티를 (re 모듈의 정규식 지원을 포함합니다) 제공하는 많은 다른 모듈들을 다룹니다.

str.capitalize()

첫 문자가 대문자이고 나머지가 소문자인 문자열의 복사본을 돌려줍니다.

버전 3.8에서 변경: 이제 첫 번째 문자는 대문자가 아닌 제목 케이스로 바뀝니다. 이는 이중 문자(digraph)와 같은 문자는 전체 문자 대신 첫 문자만 대문자로 표시된다는 뜻입니다.

str.casefold()

케이스 폴딩 된 문자열을 반환합니다. 케이스 폴딩 된 문자열은 대소문자를 무시한 매칭에 사용될 수 있습니다.

케이스 폴딩은 소문자로 변환하는 것과 비슷하지만 문자열의 모든 케이스 구분을 제거하기 때문에 보다 공격적입니다. 예를 들어, 독일어 소문자 'ß' 는 "ss" 와 동등합니다. 이미 소문자이므로 lower() 는 'ß' 에 아무런 영향을 미치지 않습니다; casefold() 는 "ss" 로 변환합니다.

The casefolding algorithm is described in section 3.13 ‘Default Case Folding’ of the Unicode Standard [https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G33992].

Added in version 3.3.

str.center(width[, fillchar])

길이 width 인 문자열의 가운데에 정렬한 값을 돌려줍니다. 지정된 fillchar (기본값은 ASCII 스페이스)을 사용하여 채웁니다. width 가 len(s) 보다 작거나 같은 경우 원래 문자열이 반환됩니다.

str.count(sub[, start[, end]])

범위 [start, end] 에서 부분 문자열 sub 가 중첩되지 않고 등장하는 횟수를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다.

If sub is empty, returns the number of empty strings between characters which is the length of the string plus one.

str.encode(encoding='utf-8', errors='strict')

Return the string encoded to bytes.

encoding defaults to 'utf-8'; see 표준 인코딩 for possible values.

errors controls how encoding errors are handled. If 'strict' (the default), a UnicodeError exception is raised. Other possible values are 'ignore', 'replace', 'xmlcharrefreplace', 'backslashreplace' and any other name registered via codecs.register_error(). See 에러 처리기 for details.

For performance reasons, the value of errors is not checked for validity unless an encoding error actually occurs, 파이썬 개발 모드 is enabled or a debug build is used.

버전 3.1에서 변경: 키워드 인자 지원이 추가되었습니다.

버전 3.9에서 변경: The value of the errors argument is now checked in 파이썬 개발 모드 and in debug mode.

str.endswith(suffix[, start[, end]])

문자열이 지정된 suffix 로 끝나면 True 를 돌려주고, 그렇지 않으면 False 를 돌려줍니다. suffix 는 찾고자 하는 접미사들의 튜플이 될 수도 있습니다. 선택적 start 가 제공되면 그 위치에서 검사를 시작합니다. 선택적 end 를 사용하면 해당 위치에서 비교를 중단합니다.

str.expandtabs(tabsize=8)

모든 탭 문자들을 현재의 열과 주어진 탭 크기에 따라 하나나 그 이상의 스페이스로 치환한 문자열의 복사본을 돌려줍니다. 탭 위치는 tabsize 문자마다 발생합니다 (기본값은 8이고, 열 0, 8, 16 등에 탭 위치를 지정합니다). 문자열을 확장하기 위해 현재 열이 0으로 설정되고 문자열을 문자 단위로 검사합니다. 문자가 탭 (\t) 이면, 현재 열이 다음 탭 위치와 같아질 때까지 하나 이상의 스페이스 문자가 삽입됩니다. (탭 문자 자체는 복사되지 않습니다.) 문자가 개행 문자 (\n) 또는 캐리지 리턴 (\r) 이면 복사되고 현재 열은 0으로 재설정됩니다. 다른 문자는 변경되지 않고 복사되고 현재 열은 인쇄할 때 문자가 어떻게 표시되는지에 관계없이 1씩 증가합니다.

>>> '01\t012\t0123\t01234'.expandtabs()
'01      012     0123    01234'
>>> '01\t012\t0123\t01234'.expandtabs(4)
'01  012 0123    01234'

str.find(sub[, start[, end]])

부분 문자열 sub 가 슬라이스 s[start:end] 내에 등장하는 가장 작은 문자열의 인덱스를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다. sub 가 없으면 -1 을 돌려줍니다.

참고

find() 메서드는 sub 의 위치를 알아야 할 경우에만 사용해야 합니다. sub 가 부분 문자열인지 확인하려면 in 연산자를 사용하십시오:

>>> 'Py' in 'Python'
True

str.format(*args, **kwargs)

문자열 포맷 연산을 수행합니다. 이 메서드가 호출되는 문자열은 리터럴 텍스트나 중괄호 {} 로 구분된 치환 필드를 포함할 수 있습니다. 각 치환 필드는 위치 인자의 숫자 인덱스나 키워드 인자의 이름을 가질 수 있습니다. 각 치환 필드를 해당 인자의 문자열 값으로 치환한 문자열의 사본을 돌려줍니다.

>>> "The sum of 1 + 2 is {0}".format(1+2)
'The sum of 1 + 2 is 3'

포맷 문자열에 지정할 수 있는 다양한 포맷 옵션에 대한 설명은 포맷 문자열 문법 을 참조하십시오.

참고

숫자(int, float, complex, decimal.Decimal와 서브 클래스)를 n 형식으로 포매팅할 때 (예: '{:n}'.format(1234)), 이 함수는 일시적으로 LC_CTYPE 로케일을 LC_NUMERIC 로케일로 설정하여 localeconv() 의 decimal_point 와 thousands_sep 필드를 디코드하는데, 이 필드들이 ASCII가 아니거나 1바이트보다 길고, LC_NUMERIC 로케일이 LC_CTYPE 로케일과 다를 때만 그렇게 합니다. 이 임시 변경은 다른 스레드에 영향을 줍니다.

버전 3.7에서 변경: 숫자를 n 형식으로 포매팅할 때, 이 함수는 어떤 경우에 일시적으로 LC_CTYPE 로케일을 LC_NUMERIC 로케일로 설정합니다.

str.format_map(mapping, /)

str.format(**mapping) 과 비슷하지만, dict로 복사되지 않고 mapping 을 직접 사용합니다. 예를 들어 mapping 이 dict 서브 클래스면 유용합니다:

>>> class Default(dict):
...     def __missing__(self, key):
...         return key
...
>>> '{name} was born in {country}'.format_map(Default(name='Guido'))
'Guido was born in country'

Added in version 3.2.

str.index(sub[, start[, end]])

find() 과 비슷하지만, 부분 문자열을 찾을 수 없는 경우 ValueError 를 일으킵니다.

str.isalnum()

문자열 내의 모든 문자가 알파벳과 숫자이고, 적어도 하나의 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. 문자 c 는 다음 중 하나가 True 를 반환하면 알파벳이거나 숫자입니다: c.isalpha(), c.isdecimal(), c.isdigit(), c.isnumeric().

str.isalpha()

Return True if all characters in the string are alphabetic and there is at least one character, False otherwise. Alphabetic characters are those characters defined in the Unicode character database as “Letter”, i.e., those with general category property being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”. Note that this is different from the Alphabetic property defined in the section 4.10 ‘Letters, Alphabetic, and Ideographic’ of the Unicode Standard [https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-4/#G91002].

str.isascii()

문자열이 비어 있거나 문자열의 모든 문자가 ASCII이면 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. ASCII 문자는 U+0000-U+007F 범위의 코드 포인트를 가집니다.

Added in version 3.7.

str.isdecimal()

문자열 내의 모든 문자가 십진수 문자이고, 적어도 하나의 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. 십진수 문자는 십진법으로 숫자를 구성할 때 사용될 수 있는 문자들입니다. 예를 들어, U+0660, ARABIC-INDIC DIGIT ZERO. 형식적으로 십진수 문자는 유니코드 일반 범주 “Nd” 에 속하는 문자입니다.

str.isdigit()

문자열 내의 모든 문자가 디짓이고, 적어도 하나의 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. 디짓에는 십진수 문자와 호환성 위 첨자 숫자와 같은 특수 처리가 필요한 숫자가 포함됩니다. 여기에는 카로슈티 숫자처럼 십진법으로 숫자를 구성할 때 사용될 수 없는 것들이 포함됩니다. 형식적으로, 디짓은 속성값이 Numeric_Type=Digit 또는 Numeric_Type=Decimal인 문자입니다.

str.isidentifier()

문자열이 섹션 section 식별자와 키워드 의 언어 정의에 따른 유효한 식별자면 True를 돌려줍니다.

keyword.iskeyword() can be used to test whether string s is a reserved identifier, such as def and class.

예제:

>>> from keyword import iskeyword

>>> 'hello'.isidentifier(), iskeyword('hello')
(True, False)
>>> 'def'.isidentifier(), iskeyword('def')
(True, True)

str.islower()

문자열 내의 모든 케이스 문자가 [4] 소문자이고, 적어도 하나의 케이스 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다.

str.isnumeric()

문자열 내의 모든 문자가 숫자이고, 적어도 하나의 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. 숫자는 디짓과 유니코드 숫자 값 속성을 갖는 모든 문자를 포함합니다. 예를 들어, U+2155, VULGAR FRACTION ONE FIFTH. 형식적으로, 숫자는 속성 값이 Numeric_Type=Digit, Numeric_Type=Decimal, Numeric_Type=Numeric인 문자입니다.

str.isprintable()

문자열 내의 모든 문자가 인쇄할 수 있거나 문자열이 비어있으면 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. 인쇄할 수 없는 문자는 유니코드 문자 데이터베이스에 “Other” 또는 “Separator”로 정의된 문자입니다. ASCII 스페이스 (0x20) 는 예외인데, 인쇄 가능한 것으로 간주합니다. (이 문맥에서, 인쇄 가능한 문자는 문자열에 repr() 을 호출했을 때 이스케이프 되지 않아야 하는 것들입니다. sys.stdout 또는 sys.stderr 로 출력되는 문자열의 처리에 영향을 주지 않습니다.)

str.isspace()

문자열 내에 공백 문자만 있고, 적어도 하나의 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다.

유니코드 문자 데이터베이스(unicodedata를 참조하십시오)에서, 일반 범주(general category)가 Zs(“Separator, space”)이거나 양방향 클래스(bidirectional class)가 WS, B 또는 S 중 하나이면 문자는 공백(whitespace)입니다.

str.istitle()

문자열이 제목 케이스 문자열이고 하나 이상의 문자가 있는 경우 True를 돌려줍니다. 예를 들어 대문자 앞에는 케이스 없는 문자만 올 수 있고 소문자는 케이스 문자 뒤에만 올 수 있습니다. 그렇지 않은 경우는 False를 돌려줍니다.

str.isupper()

문자열 내의 모든 케이스 문자가 [4] 대문자이고, 적어도 하나의 케이스 문자가 존재하는 경우 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다.

>>> 'BANANA'.isupper()
True
>>> 'banana'.isupper()
False
>>> 'baNana'.isupper()
False
>>> ' '.isupper()
False

str.join(iterable)

iterable 의 문자열들을 이어 붙인 문자열을 돌려줍니다. iterable 에 bytes 객체나 기타 문자열이 아닌 값이 있으면 TypeError 를 일으킵니다. 요소들 사이의 구분자는 이 메서드를 제공하는 문자열입니다.

str.ljust(width[, fillchar])

왼쪽으로 정렬된 문자열을 길이 width 인 문자열로 돌려줍니다. 지정된 fillchar (기본값은 ASCII 스페이스)을 사용하여 채웁니다. width 가 len(s) 보다 작거나 같은 경우 원래 문자열이 반환됩니다.

str.lower()

모든 케이스 문자 [4] 가 소문자로 변환된 문자열의 복사본을 돌려줍니다.

The lowercasing algorithm used is described in section 3.13 ‘Default Case Folding’ of the Unicode Standard [https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G33992].

str.lstrip([chars])

선행 문자가 제거된 문자열의 복사본을 돌려줍니다. chars 인자는 제거할 문자 집합을 지정하는 문자열입니다. 생략되거나 None 이라면, chars 인자의 기본값은 공백을 제거하도록 합니다. chars 인자는 접두사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> '   spacious   '.lstrip()
'spacious   '
>>> 'www.example.com'.lstrip('cmowz.')
'example.com'

문자 집합의 모든 것이 아닌 단일 접두사 문자열을 제거하는 메서드는 str.removeprefix()를 참조하십시오. 예를 들면:

>>> 'Arthur: three!'.lstrip('Arthur: ')
'ee!'
>>> 'Arthur: three!'.removeprefix('Arthur: ')
'three!'

static str.maketrans(x[, y[, z]])

이 정적 메서드는 str.translate() 에 사용할 수 있는 변환표를 돌려줍니다.

인자가 하나만 있으면 유니코드 포인트 (정수) 또는 문자 (길이가 1인 문자열)를 유니코드 포인트, 문자열 (임의 길이) 또는 None 으로 매핑하는 딕셔너리여야 합니다. 문자 키는 유니코드 포인트로 변환됩니다.

인자가 두 개면 길이가 같은 문자열이어야 하며, 결과 딕셔너리에서, x의 각 문자는 y의 같은 위치에 있는 문자로 대응됩니다. 세 번째의 인자가 있는 경우, 문자열이어야 하는데 각 문자가 None 으로 대응되는 결과를 줍니다.

str.partition(sep)

sep 가 처음 나타나는 위치에서 문자열을 나누고, 구분자 앞에 있는 부분, 구분자 자체, 구분자 뒤에 오는 부분으로 구성된 3-튜플을 돌려줍니다. 구분자가 발견되지 않으면, 문자열 자신과 그 뒤를 따르는 두 개의 빈 문자열로 구성된 3-튜플을 돌려줍니다.

str.removeprefix(prefix, /)

문자열이 prefix 문자열로 시작하면, string[len(prefix):]를 반환합니다. 그렇지 않으면, 원래 문자열의 사본을 반환합니다:

>>> 'TestHook'.removeprefix('Test')
'Hook'
>>> 'BaseTestCase'.removeprefix('Test')
'BaseTestCase'

Added in version 3.9.

str.removesuffix(suffix, /)

문자열이 suffix 문자열로 끝나고 해당 suffix가 비어 있지 않으면, string[:-len(suffix)]를 반환합니다. 그렇지 않으면, 원래 문자열의 사본을 반환합니다:

>>> 'MiscTests'.removesuffix('Tests')
'Misc'
>>> 'TmpDirMixin'.removesuffix('Tests')
'TmpDirMixin'

Added in version 3.9.

str.replace(old, new, count=-1)

Return a copy of the string with all occurrences of substring old replaced by new. If count is given, only the first count occurrences are replaced. If count is not specified or -1, then all occurrences are replaced.

버전 3.13에서 변경: count is now supported as a keyword argument.

str.rfind(sub[, start[, end]])

부분 문자열 sub 가 s[start:end] 내에 등장하는 가장 큰 문자열의 인덱스를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다. 실패하면 -1 을 돌려줍니다.

str.rindex(sub[, start[, end]])

rfind()와 비슷하지만, 부분 문자열 sub 를 찾을 수 없는 경우 ValueError 를 일으킵니다.

str.rjust(width[, fillchar])

오른쪽으로 정렬된 문자열을 길이 width 인 문자열로 돌려줍니다. 지정된 fillchar (기본값은 ASCII 스페이스)을 사용하여 채웁니다. width 가 len(s) 보다 작거나 같은 경우 원래 문자열이 반환됩니다.

str.rpartition(sep)

sep 가 마지막으로 나타나는 위치에서 문자열을 나누고, 구분자 앞에 있는 부분, 구분자 자체, 구분자 뒤에 오는 부분으로 구성된 3-튜플을 돌려줍니다. 구분자가 발견되지 않으면, 두 개의 빈 문자열과 그 뒤를 따르는 문자열 자신으로 구성된 3-튜플을 돌려줍니다.

str.rsplit(sep=None, maxsplit=-1)

sep 를 구분자 문자열로 사용하여 문자열에 있는 단어들의 리스트를 돌려줍니다. maxsplit 이 주어지면 가장 오른쪽에서 최대 maxsplit 번의 분할이 수행됩니다. sep 이 지정되지 않거나 None 이면, 구분자로 모든 공백 문자가 사용됩니다. 오른쪽에서 분리하는 것을 제외하면, rsplit()는 아래에서 자세히 설명될 split()처럼 동작합니다.

str.rstrip([chars])

후행 문자가 제거된 문자열의 복사본을 돌려줍니다. chars 인자는 제거할 문자 집합을 지정하는 문자열입니다. 생략되거나 None 이라면, chars 인자의 기본값은 공백을 제거하도록 합니다. chars 인자는 접미사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> '   spacious   '.rstrip()
'   spacious'
>>> 'mississippi'.rstrip('ipz')
'mississ'

문자 집합의 모든 것이 아닌 단일 접미사 문자열을 제거하는 메서드는 str.removesuffix()를 참조하십시오. 예를 들면:

>>> 'Monty Python'.rstrip(' Python')
'M'
>>> 'Monty Python'.removesuffix(' Python')
'Monty'

str.split(sep=None, maxsplit=-1)

sep 를 구분자 문자열로 사용하여 문자열에 있는 단어들의 리스트를 돌려줍니다. maxsplit 이 주어지면 최대 maxsplit 번의 분할이 수행됩니다 (따라서, 리스트는 최대 maxsplit+1 개의 요소를 가지게 됩니다). maxsplit 이 지정되지 않았거나 -1 이라면 분할 수에 제한이 없습니다 (가능한 모든 분할이 만들어집니다).

If sep is given, consecutive delimiters are not grouped together and are deemed to delimit empty strings (for example, '1,,2'.split(',') returns ['1', '', '2']). The sep argument may consist of multiple characters as a single delimiter (to split with multiple delimiters, use re.split()). Splitting an empty string with a specified separator returns [''].

예를 들면:

>>> '1,2,3'.split(',')
['1', '2', '3']
>>> '1,2,3'.split(',', maxsplit=1)
['1', '2,3']
>>> '1,2,,3,'.split(',')
['1', '2', '', '3', '']
>>> '1<>2<>3<4'.split('<>')
['1', '2', '3<4']

sep 이 지정되지 않거나 None 이면, 다른 분할 알고리즘이 적용됩니다: 연속된 공백 문자는 단일한 구분자로 간주하고, 문자열이 선행이나 후행 공백을 포함해도 결과는 시작과 끝에 빈 문자열을 포함하지 않습니다. 결과적으로, 빈 문자열이나 공백만으로 구성된 문자열을 None 구분자로 나누면 [] 를 돌려줍니다.

예를 들면:

>>> '1 2 3'.split()
['1', '2', '3']
>>> '1 2 3'.split(maxsplit=1)
['1', '2 3']
>>> '   1   2   3   '.split()
['1', '2', '3']

str.splitlines(keepends=False)

줄 경계에서 나눈 문자열의 줄 리스트를 돌려줍니다. keepends 가 참으로 주어지지 않는 한 결과 리스트에 줄 바꿈은 포함되지 않습니다.

이 메서드는 다음 줄 경계에서 나눕니다. 특히, 경계는 유니버설 줄 넘김 을 포함합니다.

표현

설명

\n

줄 넘김

\r

캐리지 리턴

\r\n

캐리지 리턴 + 줄 넘김

\v 또는 \x0b

수직 탭

\f 또는 \x0c

폼 피드

\x1c

파일 구분자

\x1d

그룹 구분자

\x1e

레코드 구분자

\x85

다음 줄 (C1 제어 코드)

\u2028

줄 구분자

\u2029

문단 구분자

버전 3.2에서 변경: \v 와 \f 를 줄 경계 목록에 추가했습니다.

예를 들면:

>>> 'ab c\n\nde fg\rkl\r\n'.splitlines()
['ab c', '', 'de fg', 'kl']
>>> 'ab c\n\nde fg\rkl\r\n'.splitlines(keepends=True)
['ab c\n', '\n', 'de fg\r', 'kl\r\n']

구분자 문자열 sep 이 주어졌을 때 split() 와 달리, 이 메서드는 빈 문자열에 대해서 빈 리스트를 돌려주고, 마지막 줄 바꿈은 새 줄을 만들지 않습니다:

>>> "".splitlines()
[]
>>> "One line\n".splitlines()
['One line']

비교해 보면, split('\n') 는 이렇게 됩니다:

>>> ''.split('\n')
['']
>>> 'Two lines\n'.split('\n')
['Two lines', '']

str.startswith(prefix[, start[, end]])

문자열이 지정된 prefix 로 시작하면 True 를 돌려주고, 그렇지 않으면 False 를 돌려줍니다. prefix 는 찾고자 하는 접두사들의 튜플이 될 수도 있습니다. 선택적 start 가 제공되면 그 위치에서 검사를 시작합니다. 선택적 end 를 사용하면 해당 위치에서 비교를 중단합니다.

str.strip([chars])

선행과 후행 문자가 제거된 문자열의 복사본을 돌려줍니다. chars 인자는 제거할 문자 집합을 지정하는 문자열입니다. 생략되거나 None 이라면, chars 인자의 기본값은 공백을 제거하도록 합니다. chars 인자는 접두사나 접미사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> '   spacious   '.strip()
'spacious'
>>> 'www.example.com'.strip('cmowz.')
'example'

가장 바깥쪽의 선행 또는 후행 chars 인자 값들이 문자열에서 제거됩니다. 문자는 chars 에 있는 문자 집합에 포함되지 않은 문자에 도달할 때까지 맨 앞에서 제거됩니다. 끝에서도 유사한 동작이 수행됩니다. 예를 들면:

>>> comment_string = '#....... Section 3.2.1 Issue #32 .......'
>>> comment_string.strip('.#! ')
'Section 3.2.1 Issue #32'

str.swapcase()

대문자를 소문자로, 그 반대로 마찬가지로 변환 한 문자열의 복사본을 돌려줍니다. s.swapcase().swapcase() == s 가 반드시 성립하지 않음에 주의하십시오.

str.title()

단어가 대문자로 시작하고 나머지 문자는 소문자가 되도록 문자열의 제목 케이스 버전을 돌려줍니다.

예를 들면:

>>> 'Hello world'.title()
'Hello World'

이 알고리즘은 단어를 글자들의 연속으로 보는 간단한 언어 독립적 정의를 사용합니다. 이 정의는 여러 상황에서 작동하지만, 축약과 소유의 아포스트로피가 단어 경계를 형성한다는 것을 의미하고, 이는 원하는 결과가 아닐 수도 있습니다:

>>> "they're bill's friends from the UK".title()
"They'Re Bill'S Friends From The Uk"

The string.capwords() function does not have this problem, as it splits words on spaces only.

Alternatively, a workaround for apostrophes can be constructed using regular expressions:

>>> import re
>>> def titlecase(s):
...     return re.sub(r"[A-Za-z]+('[A-Za-z]+)?",
...                   lambda mo: mo.group(0).capitalize(),
...                   s)
...
>>> titlecase("they're bill's friends.")
"They're Bill's Friends."

str.translate(table)

Return a copy of the string in which each character has been mapped through the given translation table. The table must be an object that implements indexing via __getitem__(), typically a mapping or sequence. When indexed by a Unicode ordinal (an integer), the table object can do any of the following: return a Unicode ordinal or a string, to map the character to one or more other characters; return None, to delete the character from the return string; or raise a LookupError exception, to map the character to itself.

str.maketrans() 를 사용하여 다른 형식의 문자 대 문자 매핑으로 부터 변환 맵을 만들 수 있습니다.

커스텀 문자 매핑에 대한 보다 유연한 접근법은 codecs 모듈을 참고하십시오.

str.upper()

모든 케이스 문자 [4] 가 대문자로 변환된 문자열의 복사본을 돌려줍니다. s 가 케이스 없는 문자를 포함하거나 결과 문자의 유니코드 범주가 “Lu” (Letter, 대문자) 가 아닌 경우, 예를 들어 “Lt” (Letter, 제목 케이스), s.upper().isupper() 가 False 일 수 있음에 주의하십시오.

The uppercasing algorithm used is described in section 3.13 ‘Default Case Folding’ of the Unicode Standard [https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G33992].

str.zfill(width)

길이가 width 인 문자열을 만들기 위해 ASCII '0' 문자를 왼쪽에 채운 문자열의 복사본을 돌려줍니다. 선행 부호 접두어('+'/'-')는 부호 문자의 앞이 아니라 뒤 에 채워 넣는 것으로 처리됩니다. width 가 len(s) 보다 작거나 같은 경우 원래 문자열을 돌려줍니다.

예를 들면:

>>> "42".zfill(5)
'00042'
>>> "-42".zfill(5)
'-0042'

printf 스타일 문자열 포매팅

참고

여기에 설명된 포맷 연산은 여러 가지 일반적인 오류를 (예를 들어 튜플과 딕셔너리를 올바르게 표시하지 못하는 것) 유발하는 다양한 문제점들이 있습니다. 새 포맷 문자열 리터럴 나 str.format() 인터페이스 혹은 템플릿 문자열 을 사용하면 이러한 오류를 피할 수 있습니다. 이 대안들은 또한 텍스트 포매팅에 더욱 강력하고 유연하며 확장 가능한 접근법을 제공합니다.

String objects have one unique built-in operation: the % operator (modulo). This is also known as the string formatting or interpolation operator. Given format % values (where format is a string), % conversion specifications in format are replaced with zero or more elements of values. The effect is similar to using the sprintf() function in the C language. For example:

>>> print('%s has %d quote types.' % ('Python', 2))
Python has 2 quote types.

format 이 하나의 인자를 요구하면, values 는 하나의 비 튜플 객체 일 수 있습니다. [5] 그렇지 않으면, values 는 format 문자열이 지정하는 항목의 수와 같은 튜플이거나 단일 매핑 객체 (예를 들어, 딕셔너리) 이어야 합니다.

변환 명세는 두 개 이상의 문자를 포함하며 다음과 같은 구성 요소들을 포함하는데, 반드시 이 순서대로 나와야 합니다:

'%' 문자: 명세의 시작을 나타냅니다.

매핑 키 (선택 사항): 괄호로 둘러싸인 문자들의 시퀀스로 구성됩니다 (예를 들어, (somename)).

변환 플래그 (선택 사항): 일부 변환 유형의 결과에 영향을 줍니다.

최소 필드 폭 (선택 사항): '*' (애스터리스크) 로 지정하면, 실제 폭은 values 튜플의 다음 요소에서 읽히고, 변환할 객체는 최소 필드 폭과 선택적 정밀도 뒤에 옵니다.

정밀도 (선택 사항): '.' (점) 다음에 정밀도가 옵니다. '*' (애스터리스크) 로 지정하면, 실제 정밀도는 values 튜플의 다음 요소에서 읽히고, 변환할 값은 정밀도 뒤에 옵니다.

길이 수정자 (선택 사항).

변환 유형.

오른쪽 인자가 딕셔너리 (또는 다른 매핑 형) 인 경우, 문자열에 있는 변환 명세는 반드시 '%' 문자 바로 뒤에 그 딕셔너리의 매핑 키를 괄호로 둘러싼 형태로 포함해야 합니다. 매핑 키는 포맷할 값을 매핑으로 부터 선택합니다. 예를 들어:

>>> print('%(language)s has %(number)03d quote types.' %
...       {'language': "Python", "number": 2})
Python has 002 quote types.

이 경우 * 지정자를 사용할 수 없습니다 (순차적인 매개변수 목록이 필요하기 때문입니다).

변환 플래그 문자는 다음과 같습니다:

플래그

뜻

'#'

값 변환에 “대체 형식” (아래에 정의되어있습니다) 을 사용합니다.

'0'

변환은 숫자 값의 경우 0으로 채웁니다.

'-'

변환된 값은 왼쪽으로 정렬됩니다 (둘 다 주어지면 '0' 변환보다 우선 합니다).

' '

(스페이스) 부호 있는 변환 때문에 만들어진 양수 앞에 빈칸을 남겨둡니다 (음수면 빈 문자열입니다).

'+'

부호 문자 ('+' or '-') 가 변환 앞에 놓입니다 (' ' 플래그에 우선합니다).

길이 수정자 (h, l, L) 를 제공할 수는 있지만, 파이썬에서 필요하지 않기 때문에 무시됩니다 – 예를 들어 %ld 는 %d 와 같습니다.

변환 유형은 다음과 같습니다:

변환

뜻

노트

'd'

부호 있는 정수 십진 표기.

'i'

부호 있는 정수 십진 표기.

'o'

부호 있는 8진수 값.

(1)

'u'

쓸데없는 유형 – 'd' 와 같습니다.

(6)

'x'

부호 있는 16진수 (소문자).

(2)

'X'

부호 있는 16진수 (대문자).

(2)

'e'

Floating-point exponential format (lowercase).

(3)

'E'

Floating-point exponential format (uppercase).

(3)

'f'

Floating-point decimal format.

(3)

'F'

Floating-point decimal format.

(3)

'g'

Floating-point format. Uses lowercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.

(4)

'G'

Floating-point format. Uses uppercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.

(4)

'c'

단일 문자 (정수 또는 길이 1인 문자열을 허용합니다).

'r'

문자열 (repr()을 사용하여 파이썬 객체를 변환합니다).

(5)

's'

문자열 (str() 을 사용하여 파이썬 객체를 변환합니다).

(5)

'a'

문자열 (ascii() 를 사용하여 파이썬 객체를 변환합니다).

(5)

'%'

인자는 변환되지 않고, 결과에 '%' 문자가 표시됩니다.

노트:

대체 형식은 첫 번째 숫자 앞에 선행 8진수 지정자 ('0o')를 삽입합니다.

대체 형식은 첫 번째 숫자 앞에 선행 '0x' 또는 '0X' ('x' 나 'X' 유형 중 어느 것을 사용하느냐에 따라 달라집니다) 를 삽입합니다.

대체 형식은 그 뒤에 숫자가 나오지 않더라도 항상 소수점을 포함합니다.

정밀도는 소수점 이하 자릿수를 결정하며 기본값은 6입니다.

대체 형식은 결과에 항상 소수점을 포함하고 뒤에 오는 0은 제거되지 않습니다.

정밀도는 소수점 앞뒤의 유효 자릿수를 결정하며 기본값은 6입니다.

정밀도가 N 이라면, 출력은 N 문자로 잘립니다.

PEP 237 [https://peps.python.org/pep-0237/]을 참조하세요.

파이썬 문자열은 명시적인 길이를 가지고 있으므로, %s 변환은 문자열의 끝이 '\0' 이라고 가정하지 않습니다.

버전 3.1에서 변경: 절댓값이 1e50 을 넘는 숫자에 대한 %f 변환은 더는 %g 변환으로 대체되지 않습니다.

바이너리 시퀀스 형 — bytes, bytearray, memoryview

바이너리 데이터를 조작하기 위한 핵심 내장형은 bytes 와 bytearray 입니다. 이것들은 memoryview 에 의해 지원되는데, 다른 바이너리 객체들의 메모리에 복사 없이 접근하기 위해 버퍼 프로토콜 을 사용합니다.

array 모듈은 32-비트 정수와 IEEE754 배정도 부동 소수점 같은 기본 데이터형의 효율적인 저장을 지원합니다.

바이트열 객체

바이트열 객체는 단일 바이트들의 불변 시퀀스입니다. 많은 주요 바이너리 프로토콜이 ASCII 텍스트 인코딩을 기반으로 하므로, 바이트열 객체는 ASCII 호환 데이터로 작업 할 때만 유효한 여러 가지 메서드를 제공하며 다양한 다른 방법으로 문자열 객체와 밀접한 관련이 있습니다.

class bytes([source[, encoding[, errors]]])

첫째로, 바이트열 리터럴의 문법은 문자열 리터럴과 거의 같지만 b 접두사가 추가된다는 점이 다릅니다.:

작은따옴표: b'still allows embedded "double" quotes'

Double quotes: b"still allows embedded 'single' quotes"

삼중 따옴표: b'''3 single quotes''', b"""3 double quotes"""

바이트열 리터럴에는 ASCII 문자만 허용됩니다 (선언된 소스 코드 인코딩과 관계없습니다). 127 보다 큰 바이너리 값은 적절한 이스케이프 시퀀스를 사용하여 바이트열 리터럴에 입력해야 합니다.

문자열 리터럴의 경우와 마찬가지로 바이트열 리터럴은 이스케이프 시퀀스 처리를 비활성화하기 위해 r 접두사를 사용할 수도 있습니다. 지원되는 이스케이프 시퀀스를 포함하여 바이트열 리터럴의 다양한 형식에 대한 자세한 내용은 문자열과 바이트열 리터럴 을 참조하십시오.

바이트열 리터럴과 그 표현은 ASCII 텍스트를 기반으로 하지만, 바이트열 객체는 실제로는 정수의 불변 시퀀스처럼 동작하고, 시퀀스의 각 값은 0 <= x < 256 이 되도록 제한됩니다 (이 제한을 위반하려고 시도하면 ValueError 를 일으킵니다). 이것은 많은 바이너리 형식이 ASCII 기반 요소를 포함하고 일부 텍스트 지향 알고리즘으로 유용하게 조작될 수 있지만, 임의의 바이너리 데이터에 일반적으로 적용될 수는 없음을 강조하기 위한 것입니다 (텍스트 처리 알고리즘을 맹목적으로 ASCII 호환이 아닌 바이너리 데이터 형식에 적용하면 대개 데이터 손상으로 이어집니다).

리터럴 형식 외에도, 바이트열 객체는 여러 가지 다른 방법으로 만들 수 있습니다.:

지정된 길이의 0으로 채워진 바이트열 객체: bytes(10)

정수의 이터러블로부터: bytes(range(20))

버퍼 프로토콜을 통해 기존 바이너리 데이터 복사: bytes(obj)

내장 bytes 도 참조하세요.

2개의 16진수는 정확히 하나의 바이트에 대응하기 때문에 16진수는 바이너리 데이터를 설명하는 데 일반적으로 사용되는 형식입니다. 따라서, 바이트열 형은 그 형식의 데이터를 읽는 추가의 클래스 메서드를 갖습니다:

classmethod fromhex(string)

이 bytes 클래스 메서드는 주어진 문자열 객체를 디코딩해서 바이트열 객체를 돌려줍니다. 문자열은 바이트 당 두 개의 16진수가 포함되어야 하며 ASCII 공백은 무시됩니다.

>>> bytes.fromhex('2Ef0 F1f2  ')
b'.\xf0\xf1\xf2'

버전 3.7에서 변경: 이제 bytes.fromhex() 는 스페이스뿐만 아니라 문자열에 있는 모든 ASCII 공백을 건너뜁니다.

바이트열 객체를 16진수 표현으로 변환하기 위한 역변환 함수가 있습니다.

hex([sep[, bytes_per_sep]])

인스턴스의 바이트마다 2 자릿수의 16진수로 표현한 문자열 객체를 돌려줍니다.

>>> b'\xf0\xf1\xf2'.hex()
'f0f1f2'

If you want to make the hex string easier to read, you can specify a single character separator sep parameter to include in the output. By default, this separator will be included between each byte. A second optional bytes_per_sep parameter controls the spacing. Positive values calculate the separator position from the right, negative values from the left.

>>> value = b'\xf0\xf1\xf2'
>>> value.hex('-')
'f0-f1-f2'
>>> value.hex('_', 2)
'f0_f1f2'
>>> b'UUDDLRLRAB'.hex(' ', -4)
'55554444 4c524c52 4142'

Added in version 3.5.

버전 3.8에서 변경: 이제 bytes.hex()는 16진수 출력의 바이트 사이에 구분 기호를 삽입하기 위해 선택적 sep과 bytes_per_sep 매개 변수를 지원합니다.

바이트열 객체는 정수의 시퀀스(튜플과 유사)이기 때문에, 바이트열 객체 b 에 대해서, b[0] 는 정수가 됩니다. 반면, b[0:1] 는 길이 1인 바이트열 객체가 됩니다. (이것은 인덱싱과 슬라이싱 모두 길이 1인 문자열을 생성하는 텍스트 문자열과 대조됩니다)

바이트열 객체의 표현은 리터럴 형식 (b'...') 을 사용하는데, 종종 bytes([46, 46, 46]) 보다 유용하기 때문입니다. list(b) 를 사용하면 바이트열 객체를 항상 정수 리스트로 변환할 수 있습니다.

바이트 배열 객체

bytearray 객체는 bytes 객체의 가변형입니다.

class bytearray([source[, encoding[, errors]]])

바이트 배열 객체에 대한 전용 리터럴 문법은 없으며 항상 생성자를 호출하여 만듭니다:

빈 인스턴스 만들기: bytearray()

주어진 길이의 0으로 채워진 인스턴스 만들기: bytearray(10)

정수의 이터러블로부터: bytearray(range(20))

버퍼 프로토콜을 통해 기존 바이너리 데이터 복사: bytearray(b'Hi!')

바이트 배열 객체는 가변이기 때문에, 바이트열 과 바이트 배열 연산 에 설명되어있는 공통 바이트열과 바이트 배열 연산에 더해, 가변 시퀀스 연산도 지원합니다.

내장 bytearray 도 참조하세요.

2개의 16진수는 정확히 하나의 바이트에 대응하기 때문에 16진수는 바이너리 데이터를 설명하는 데 일반적으로 사용되는 형식입니다. 따라서, 바이트 배열형은 그 형식의 데이터를 읽는 추가의 클래스 메서드를 갖습니다:

classmethod fromhex(string)

이 bytearray 클래스 메서드는 주어진 문자열 객체를 디코딩해서 바이트 배열 객체를 돌려줍니다. 문자열은 바이트 당 두 개의 16진수가 포함되어야 하며 ASCII 공백은 무시됩니다.

>>> bytearray.fromhex('2Ef0 F1f2  ')
bytearray(b'.\xf0\xf1\xf2')

버전 3.7에서 변경: 이제 bytearray.fromhex() 는 스페이스뿐만 아니라 문자열에 있는 모든 ASCII 공백을 건너뜁니다.

바이트 배열 객체를 16진수 표현으로 변환하기 위한 역변환 함수가 있습니다.

hex([sep[, bytes_per_sep]])

인스턴스의 바이트마다 2 자릿수의 16진수로 표현한 문자열 객체를 돌려줍니다.

>>> bytearray(b'\xf0\xf1\xf2').hex()
'f0f1f2'

Added in version 3.5.

버전 3.8에서 변경: bytes.hex()와 비슷하게, 이제 bytearray.hex()는 16진수 출력의 바이트 사이에 구분 기호를 삽입하기 위해 선택적 sep과 bytes_per_sep 매개 변수를 지원합니다.

바이트 배열 객체는 정수의 시퀀스(리스트와 유사)이기 때문에, 바이트 배열 객체 b 에 대해서, b[0] 는 정수가 됩니다. 반면, b[0:1] 는 길이 1인 바이트 배열 객체가 됩니다. (이것은 인덱싱과 슬라이싱 모두 길이 1인 문자열을 생성하는 텍스트 문자열과 대조됩니다)

바이트 배열 객체의 표현은 바이트열 리터럴 형식 (bytearray(b'...')) 을 사용하는데, 종종 bytearray([46, 46, 46]) 보다 유용하기 때문입니다. list(b) 를 사용하면 바이트 배열 객체를 항상 정수 리스트로 변환할 수 있습니다.

바이트열 과 바이트 배열 연산

바이트열와 바이트 배열 객체는 공통 시퀀스 연산을 지원합니다. 이것들은 같은 형의 피연산자뿐만 아니라 모든 bytes-like object와 상호 운용됩니다. 이러한 유연성으로 인해, 오류 없이 작업을 자유롭게 혼합할 수 있습니다. 그러나, 결과의 반환형은 피연산자의 순서에 따라 달라질 수 있습니다.

참고

바이트열 및 바이트 배열 객체의 메서드는 인자로 문자열을 받아들이지 않습니다, 문자열의 메서드가 바이트열을 인자로 허용하지 않는 것과 마찬가지입니다. 예를 들어, 다음과 같이 작성해야 합니다:

a = "abc"
b = a.replace("a", "f")

그리고:

a = b"abc"
b = a.replace(b"a", b"f")

일부 바이트열 및 바이트 배열 연산은 ASCII 호환 바이너리 형식을 가정하므로, 임의의 바이너리 데이터로 작업 할 때는 피해야 합니다. 이러한 제한 사항은 아래에서 다룹니다.

참고

이러한 ASCII 기반 연산을 사용하여 ASCII 기반 형식으로 저장되지 않은 바이너리 데이터를 조작하면 데이터가 손상될 수 있습니다.

바이트열 및 바이트 배열 객체에 대한 다음 메서드는 임의의 바이너리 데이터와 함께 사용할 수 있습니다.

bytes.count(sub[, start[, end]])

bytearray.count(sub[, start[, end]])

범위 [start, end] 에서 서브 시퀀스 sub 가 중첩되지 않고 등장하는 횟수를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다.

검색할 서브 시퀀스는 임의의 bytes-like object 또는 0에서 255 사이의 정수일 수 있습니다.

If sub is empty, returns the number of empty slices between characters which is the length of the bytes object plus one.

버전 3.3에서 변경: 서브 시퀀스로 0에서 255 사이의 정수도 허용합니다.

bytes.removeprefix(prefix, /)

bytearray.removeprefix(prefix, /)

바이너리 데이터가 prefix 문자열로 시작하면, bytes[len(prefix):]를 반환합니다. 그렇지 않으면, 원래 바이너리 데이터의 사본을 반환합니다:

>>> b'TestHook'.removeprefix(b'Test')
b'Hook'
>>> b'BaseTestCase'.removeprefix(b'Test')
b'BaseTestCase'

prefix는 임의의 바이트열류 객체 일 수 있습니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

Added in version 3.9.

bytes.removesuffix(suffix, /)

bytearray.removesuffix(suffix, /)

바이너리 데이터가 suffix 문자열로 끝나고 해당 suffix가 비어 있지 않으면 bytes[:-len(suffix)]를 반환합니다. 그렇지 않으면, 원래 바이너리 데이터의 사본을 반환합니다:

>>> b'MiscTests'.removesuffix(b'Tests')
b'Misc'
>>> b'TmpDirMixin'.removesuffix(b'Tests')
b'TmpDirMixin'

suffix는 임의의 바이트열류 객체 일 수 있습니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

Added in version 3.9.

bytes.decode(encoding='utf-8', errors='strict')

bytearray.decode(encoding='utf-8', errors='strict')

Return the bytes decoded to a str.

encoding defaults to 'utf-8'; see 표준 인코딩 for possible values.

errors controls how decoding errors are handled. If 'strict' (the default), a UnicodeError exception is raised. Other possible values are 'ignore', 'replace', and any other name registered via codecs.register_error(). See 에러 처리기 for details.

For performance reasons, the value of errors is not checked for validity unless a decoding error actually occurs, 파이썬 개발 모드 is enabled or a debug build is used.

참고

Passing the encoding argument to str allows decoding any bytes-like object directly, without needing to make a temporary bytes or bytearray object.

버전 3.1에서 변경: 키워드 인자 지원이 추가되었습니다.

버전 3.9에서 변경: The value of the errors argument is now checked in 파이썬 개발 모드 and in debug mode.

bytes.endswith(suffix[, start[, end]])

bytearray.endswith(suffix[, start[, end]])

바이너리 데이터가 지정된 suffix 로 끝나면 True 를 돌려주고, 그렇지 않으면 False 를 돌려줍니다. suffix 는 찾고자 하는 접미사들의 튜플이 될 수도 있습니다. 선택적 start 가 제공되면 그 위치에서 검사를 시작합니다. 선택적 end 를 사용하면 해당 위치에서 비교를 중단합니다.

검색할 접미사(들)는 임의의 bytes-like object 일 수 있습니다.

bytes.find(sub[, start[, end]])

bytearray.find(sub[, start[, end]])

서브 시퀀스 sub 가 슬라이스 s[start:end] 내에 등장하는 가장 작은 데이터의 인덱스를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다. sub 가 없으면 -1 을 돌려줍니다.

검색할 서브 시퀀스는 임의의 bytes-like object 또는 0에서 255 사이의 정수일 수 있습니다.

참고

find() 메서드는 sub 의 위치를 알아야 할 경우에만 사용해야 합니다. sub 가 부분 문자열인지 여부를 확인하려면 in 연산자를 사용하십시오:

>>> b'Py' in b'Python'
True

버전 3.3에서 변경: 서브 시퀀스로 0에서 255 사이의 정수도 허용합니다.

bytes.index(sub[, start[, end]])

bytearray.index(sub[, start[, end]])

find() 과 비슷하지만, 서브 시퀀스를 찾을 수 없는 경우 ValueError 를 일으킵니다.

검색할 서브 시퀀스는 임의의 bytes-like object 또는 0에서 255 사이의 정수일 수 있습니다.

버전 3.3에서 변경: 서브 시퀀스로 0에서 255 사이의 정수도 허용합니다.

bytes.join(iterable)

bytearray.join(iterable)

iterable 의 바이너리 데이터 시퀀스들을 이어 붙이기 한 바이트열 또는 바이트 배열 객체를 돌려줍니다. iterable 에 str 객체나 기타 bytes-like object 가 아닌 값이 있으면 TypeError 를 일으킵니다. 요소들 사이의 구분자는 이 메서드를 제공하는 바이트열 이나 바이트 배열 객체입니다.

static bytes.maketrans(from, to)

static bytearray.maketrans(from, to)

이 정적 메서드는 bytes.translate() 에 사용할 수 있는 변환표를 돌려주는데, from 에 있는 문자를 to 의 같은 위치에 있는 문자로 매핑합니다; from 과 to 는 모두 bytes-like object 여야 하고 길이가 같아야 합니다.

Added in version 3.1.

bytes.partition(sep)

bytearray.partition(sep)

sep 가 처음 나타나는 위치에서 시퀀스를 나누고, 구분자 앞에 있는 부분, 구분자 자체, 구분자 뒤에 오는 부분으로 구성된 3-튜플을 돌려줍니다. 구분자가 발견되지 않으면, 원래 시퀀스의 복사본과 그 뒤를 따르는 두 개의 빈 바이트열 또는 바이트 배열 객체로 구성된 3-튜플을 돌려줍니다.

검색할 구분자는 임의의 bytes-like object 일 수 있습니다.

bytes.replace(old, new[, count])

bytearray.replace(old, new[, count])

모든 서브 시퀀스 old 가 new 로 치환된 시퀀스의 복사본을 돌려줍니다. 선택적 인자 count 가 주어지면, 앞의 count 개만 치환됩니다.

검색할 서브 시퀀스와 그 대체물은 임의의 bytes-like object 일 수 있습니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.rfind(sub[, start[, end]])

bytearray.rfind(sub[, start[, end]])

서브 시퀀스 sub 가 s[start:end] 내에 등장하는 가장 큰 시퀀스의 인덱스를 돌려줍니다. 선택적 인자 start 와 end 는 슬라이스 표기법으로 해석됩니다. 실패하면 -1 을 돌려줍니다.

검색할 서브 시퀀스는 임의의 bytes-like object 또는 0에서 255 사이의 정수일 수 있습니다.

버전 3.3에서 변경: 서브 시퀀스로 0에서 255 사이의 정수도 허용합니다.

bytes.rindex(sub[, start[, end]])

bytearray.rindex(sub[, start[, end]])

rfind() 와 비슷하지만, 서브 시퀀스 sub 를 찾을 수 없는 경우 ValueError 를 일으킵니다.

검색할 서브 시퀀스는 임의의 bytes-like object 또는 0에서 255 사이의 정수일 수 있습니다.

버전 3.3에서 변경: 서브 시퀀스로 0에서 255 사이의 정수도 허용합니다.

bytes.rpartition(sep)

bytearray.rpartition(sep)

sep 가 마지막으로 나타나는 위치에서 시퀀스를 나누고, 구분자 앞에 있는 부분, 구분자 자체, 구분자 뒤에 오는 부분으로 구성된 3-튜플을 돌려줍니다. 구분자가 발견되지 않으면, 두 개의 빈 바이트열 또는 바이트 배열 객체와 그 뒤를 따르는 원래 시퀀스의 복사본으로 구성된 3-튜플을 돌려줍니다.

검색할 구분자는 임의의 bytes-like object 일 수 있습니다.

bytes.startswith(prefix[, start[, end]])

bytearray.startswith(prefix[, start[, end]])

바이너리 데이터가 지정된 prefix 로 시작하면 True 를 돌려주고, 그렇지 않으면 False 를 돌려줍니다. prefix 는 찾고자 하는 접두사들의 튜플이 될 수도 있습니다. 선택적 start 가 제공되면 그 위치에서 검사를 시작합니다. 선택적 end 를 사용하면 해당 위치에서 비교를 중단합니다.

검색할 접두사(들)는 임의의 bytes-like object 일 수 있습니다.

bytes.translate(table, /, delete=b'')

bytearray.translate(table, /, delete=b'')

생략 가능한 인자 delete 의 모든 바이트를 제거하고, 나머지 바이트들을 주어진 변환표로 매핑한 바이트열이나 바이트 배열 객체의 복사본을 돌려줍니다. table은 길이 256인 바이트열 객체이어야 합니다.

bytes.maketrans() 메서드를 사용하여 변환표를 만들 수 있습니다.

문자를 지우기만 하는 변환에는 table 인자를 None 으로 설정하십시오:

>>> b'read this short text'.translate(None, b'aeiou')
b'rd ths shrt txt'

버전 3.6에서 변경: 이제 delete 는 키워드 인자로 지원됩니다.

바이트열 및 바이트 배열 객체에 대한 다음 메서드는 ASCII 호환 바이너리 형식의 사용을 가정하는 기본 동작을 갖지만, 적절한 인자를 전달하여 임의의 바이너리 데이터와 함께 사용할 수 있습니다. 이 섹션의 바이트 배열 메서드는 모두 제자리에서 작동하지 않고 대신 새로운 객체를 생성함에 주의하십시오.

bytes.center(width[, fillbyte])

bytearray.center(width[, fillbyte])

길이 width 인 시퀀스의 가운데에 정렬한 객체의 복사본을 돌려줍니다. 지정된 fillbyte (기본값은 ASCII 스페이스)를 사용하여 채웁니다. bytes 객체의 경우, width 가 len(s) 보다 작거나 같은 경우 원래 시퀀스가 반환됩니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.ljust(width[, fillbyte])

bytearray.ljust(width[, fillbyte])

왼쪽으로 정렬된 객체의 복사본을 길이 width 인 시퀀스로 돌려줍니다. 지정된 fillbyte (기본값은 ASCII 스페이스)을 사용하여 채웁니다. bytes 객체의 경우, width 가 len(s) 보다 작거나 같은 경우 원래 시퀀스가 반환됩니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.lstrip([chars])

bytearray.lstrip([chars])

선행 바이트가 제거된 시퀀스의 복사본을 돌려줍니다. chars 인자는 제거할 바이트 집합을 지정하는 바이너리 시퀀스입니다 - 이름은 이 메서드가 보통 ASCII 문자와 사용된다는 사실을 반영합니다. 생략되거나 None 이라면, chars 인자의 기본값은 ASCII 공백을 제거하도록 합니다. chars 인자는 접두사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> b'   spacious   '.lstrip()
b'spacious   '
>>> b'www.example.com'.lstrip(b'cmowz.')
b'example.com'

제거할 바이트 값의 바이너리 시퀀스는 임의의 바이트열류 객체일 수 있습니다. 문자 집합의 모든 것이 아닌 단일 접두사 문자열을 제거하는 메서드는 removeprefix()를 참조하십시오. 예를 들면:

>>> b'Arthur: three!'.lstrip(b'Arthur: ')
b'ee!'
>>> b'Arthur: three!'.removeprefix(b'Arthur: ')
b'three!'

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.rjust(width[, fillbyte])

bytearray.rjust(width[, fillbyte])

오른쪽으로 정렬된 객체의 복사본을 길이 width 인 시퀀스로 돌려줍니다. 지정된 fillbyte (기본값은 ASCII 스페이스)를 사용하여 채웁니다. bytes 객체의 경우, width 가 len(s) 보다 작거나 같은 경우 원래 시퀀스가 반환됩니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.rsplit(sep=None, maxsplit=-1)

bytearray.rsplit(sep=None, maxsplit=-1)

sep 을 구분자 시퀀스로 사용하여 바이너리 시퀀스를 같은 형의 서브 시퀀스로 나눕니다. maxsplit 이 주어지면 가장 오른쪽에서 최대 maxsplit 번의 분할이 수행됩니다. sep 이 지정되지 않거나 None 이면, ASCII 공백 문자만으로 이루어진 모든 서브 시퀀스는 구분자입니다. 오른쪽에서 분리하는 것을 제외하면, rsplit()는 아래에서 자세히 설명될 split()처럼 동작합니다.

bytes.rstrip([chars])

bytearray.rstrip([chars])

지정된 후행 바이트가 제거된 시퀀스의 복사본을 돌려줍니다. chars 인자는 제거할 바이트 집합을 지정하는 바이너리 시퀀스입니다 - 이름은 이 메서드가 보통 ASCII 문자와 사용된다는 사실을 반영합니다. 생략되거나 None 이라면, chars 인자의 기본값은 ASCII 공백을 제거하도록 합니다. chars 인자는 접미사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> b'   spacious   '.rstrip()
b'   spacious'
>>> b'mississippi'.rstrip(b'ipz')
b'mississ'

제거할 바이트 값의 바이너리 시퀀스는 임의의 바이트열류 객체일 수 있습니다. 문자 집합의 모든 것이 아닌 단일 접미사 문자열을 제거하는 메서드는 removesuffix()를 참조하십시오. 예를 들면:

>>> b'Monty Python'.rstrip(b' Python')
b'M'
>>> b'Monty Python'.removesuffix(b' Python')
b'Monty'

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.split(sep=None, maxsplit=-1)

bytearray.split(sep=None, maxsplit=-1)

sep 를 구분자 시퀀스로 사용하여 바이너리 시퀀스를 같은 형의 서브 시퀀스로 나눕니다. maxsplit 이 지정되고 음수가 아닌 경우, 최대 maxsplit 분할이 수행됩니다 (따라서, 리스트는 최대 maxsplit+1 개의 요소를 가지게 됩니다). maxsplit 이 지정되지 않았거나 -1 이라면 분할 수에 제한이 없습니다 (가능한 모든 분할이 만들어집니다).

If sep is given, consecutive delimiters are not grouped together and are deemed to delimit empty subsequences (for example, b'1,,2'.split(b',') returns [b'1', b'', b'2']). The sep argument may consist of a multibyte sequence as a single delimiter. Splitting an empty sequence with a specified separator returns [b''] or [bytearray(b'')] depending on the type of object being split. The sep argument may be any bytes-like object.

예를 들면:

>>> b'1,2,3'.split(b',')
[b'1', b'2', b'3']
>>> b'1,2,3'.split(b',', maxsplit=1)
[b'1', b'2,3']
>>> b'1,2,,3,'.split(b',')
[b'1', b'2', b'', b'3', b'']
>>> b'1<>2<>3<4'.split(b'<>')
[b'1', b'2', b'3<4']

sep 이 지정되지 않거나 None 이면, 다른 분할 알고리즘이 적용됩니다: 연속된 ASCII 공백 문자는 단일한 구분자로 간주하고, 시퀀스가 선행이나 후행 공백을 포함해도 결과는 시작과 끝에 빈 시퀀스를 포함하지 않습니다. 결과적으로, 빈 시퀀스나 ASCII 공백만으로 구성된 시퀀스를 None 구분자로 나누면 [] 를 돌려줍니다.

예를 들면:

>>> b'1 2 3'.split()
[b'1', b'2', b'3']
>>> b'1 2 3'.split(maxsplit=1)
[b'1', b'2 3']
>>> b'   1   2   3   '.split()
[b'1', b'2', b'3']

bytes.strip([chars])

bytearray.strip([chars])

선행과 후행 바이트가 제거된 시퀀스의 복사본을 돌려줍니다. chars 인자는 제거할 바이트 집합을 지정하는 바이너리 시퀀스입니다 - 이름은 이 메서드가 보통 ASCII 문자와 사용된다는 사실을 반영합니다. 생략되거나 None 이라면, chars 인자의 기본값은 ASCII 공백을 제거하도록 합니다. chars 인자는 접두사나 접미사가 아닙니다; 모든 값 조합이 제거됩니다:

>>> b'   spacious   '.strip()
b'spacious'
>>> b'www.example.com'.strip(b'cmowz.')
b'example'

제거할 바이트 값의 바이너리 시퀀스는 임의의 bytes-like object 일 수 있습니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

바이트열 및 바이트 배열 객체에 대한 다음 메서드는 ASCII 호환 바이너리 형식의 사용을 가정하며 임의의 바이너리 데이터에 적용하면 안 됩니다. 이 섹션의 바이트 배열 메서드는 모두 제자리에서 작동하지 않고 대신 새로운 객체를 생성합니다.

bytes.capitalize()

bytearray.capitalize()

각 바이트가 ASCII 문자로 해석되고 첫 번째 바이트는 대문자로, 나머지는 소문자로 만든 시퀀스의 복사본을 돌려줍니다. ASCII 바이트가 아닌 값들은 변경되지 않고 전달됩니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.expandtabs(tabsize=8)

bytearray.expandtabs(tabsize=8)

모든 ASCII 탭 문자들을 현재의 열과 주어진 탭 크기에 따라 하나나 그 이상의 ASCII 스페이스로 치환한 시퀀스의 복사본을 돌려줍니다. 탭 위치는 tabsize 바이트마다 발생합니다 (기본값은 8이고, 열 0, 8, 16 등에 탭 위치를 지정합니다). 시퀀스를 확장하기 위해 현재 열이 0으로 설정되고 시퀀스를 바이트 단위로 검사합니다. 바이트가 ASCII 탭 문자 (b'\t') 이면, 현재 열이 다음 탭 위치와 같아질 때까지 하나 이상의 스페이스 문자가 삽입됩니다. (탭 문자 자체는 복사되지 않습니다.) 현재 바이트가 ASCII 개행 문자 (b'\n') 또는 캐리지 리턴 (b'\r') 이면 복사되고 현재 열은 0으로 재설정됩니다. 다른 바이트는 변경되지 않고 복사되고 현재 열은 인쇄할 때 바이트가 어떻게 표시되는지에 관계없이 1씩 증가합니다.

>>> b'01\t012\t0123\t01234'.expandtabs()
b'01      012     0123    01234'
>>> b'01\t012\t0123\t01234'.expandtabs(4)
b'01  012 0123    01234'

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.isalnum()

bytearray.isalnum()

시퀀스의 모든 바이트가 알파벳 ASCII 문자 또는 ASCII 십진수이고 시퀀스가 비어 있지 않으면 True를 돌려주고 그렇지 않으면 False를 돌려줍니다. 알파벳 ASCII 문자는, 시퀀스 b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다. ASCII 십진수는 시퀀스 b'0123456789' 에 있는 바이트 값입니다.

예를 들면:

>>> b'ABCabc1'.isalnum()
True
>>> b'ABC abc1'.isalnum()
False

bytes.isalpha()

bytearray.isalpha()

시퀀스의 모든 바이트가 알파벳 ASCII 문자이고 시퀀스가 비어 있지 않으면 True를 돌려주고 그렇지 않으면 False를 돌려줍니다. 알파벳 ASCII 문자는, 시퀀스 b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

예를 들면:

>>> b'ABCabc'.isalpha()
True
>>> b'ABCabc1'.isalpha()
False

bytes.isascii()

bytearray.isascii()

시퀀스가 비어 있거나 시퀀스의 모든 바이트가 ASCII면 True를 돌려주고, 그렇지 않으면 False를 돌려줍니다. ASCII 바이트의 범위는 0-0x7F 입니다.

Added in version 3.7.

bytes.isdigit()

bytearray.isdigit()

시퀀스의 모든 바이트가 ASCII 십진수이며 시퀀스가 비어 있지 않으면 True를 돌려주고 그렇지 않으면 False를 돌려줍니다. ASCII 십진수는 시퀀스 b'0123456789' 에 있는 바이트 값입니다.

예를 들면:

>>> b'1234'.isdigit()
True
>>> b'1.23'.isdigit()
False

bytes.islower()

bytearray.islower()

시퀀스에 적어도 하나의 ASCII 소문자가 있고, ASCII 대문자가 없으면 True를, 그렇지 않으면 False를 돌려줍니다.

예를 들면:

>>> b'hello world'.islower()
True
>>> b'Hello world'.islower()
False

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는, 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

bytes.isspace()

bytearray.isspace()

시퀀스의 모든 바이트가 ASCII 공백이고, 시퀀스가 비어 있지 않으면 True를 돌려주고 그렇지 않으면 False를 돌려줍니다. ASCII 공백 문자는 시퀀스 b' \t\n\r\x0b\f'(스페이스, 탭, 줄 바꿈, 캐리지 리턴, 수직 탭, 폼 피드)에 있는 바이트 값입니다.

bytes.istitle()

bytearray.istitle()

시퀀스가 ASCII 제목 케이스고 시퀀스가 비어있지 않으면 True를 돌려주고 그렇지 않으면 False를 돌려줍니다. “제목 케이스” 의 정의에 대한 자세한 내용은 bytes.title() 을 참조하십시오.

예를 들면:

>>> b'Hello World'.istitle()
True
>>> b'Hello world'.istitle()
False

bytes.isupper()

bytearray.isupper()

시퀀스에 적어도 하나의 ASCII 대문자가 있고, ASCII 소문자가 없으면 True를, 그렇지 않으면 False를 돌려줍니다.

예를 들면:

>>> b'HELLO WORLD'.isupper()
True
>>> b'Hello world'.isupper()
False

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는, 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

bytes.lower()

bytearray.lower()

모든 ASCII 대문자를 해당 소문자로 변환한 시퀀스의 복사본을 돌려줍니다.

예를 들면:

>>> b'Hello World'.lower()
b'hello world'

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는, 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.splitlines(keepends=False)

bytearray.splitlines(keepends=False)

ASCII 줄 경계에서 나눈 바이너리 시퀀스의 줄 리스트를 돌려줍니다. 이 메서드는 줄을 나누는데 universal newlines 접근법을 사용합니다. keepends 가 참으로 주어지지 않는 한 결과 리스트에 줄 바꿈은 포함되지 않습니다.

예를 들면:

>>> b'ab c\n\nde fg\rkl\r\n'.splitlines()
[b'ab c', b'', b'de fg', b'kl']
>>> b'ab c\n\nde fg\rkl\r\n'.splitlines(keepends=True)
[b'ab c\n', b'\n', b'de fg\r', b'kl\r\n']

구분자 시퀀스 sep 이 주어졌을 때 split() 와 달리, 이 메서드는 빈 시퀀스에 대해서 빈 리스트를 돌려주고, 마지막 줄 바꿈은 새 줄을 만들지 않습니다:

>>> b"".split(b'\n'), b"Two lines\n".split(b'\n')
([b''], [b'Two lines', b''])
>>> b"".splitlines(), b"One line\n".splitlines()
([], [b'One line'])

bytes.swapcase()

bytearray.swapcase()

모든 ASCII 소문자를 해당 대문자로, 그 반대도 마찬가지로 변환한 시퀀스의 복사본을 돌려줍니다.

예를 들면:

>>> b'Hello World'.swapcase()
b'hELLO wORLD'

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는, 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

Unlike str.swapcase(), it is always the case that bin.swapcase().swapcase() == bin for the binary versions. Case conversions are symmetrical in ASCII, even though that is not generally true for arbitrary Unicode code points.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.title()

bytearray.title()

단어가 ASCII 대문자로 시작하고 나머지 문자들은 소문자인 제목 케이스 버전의 바이너리 시퀀스를 돌려줍니다. 케이스 없는 바이트 값은 수정되지 않은 상태로 남습니다.

예를 들면:

>>> b'Hello world'.title()
b'Hello World'

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다. 다른 모든 바이트 값은 케이스가 없습니다.

이 알고리즘은 단어를 글자들의 연속으로 보는 간단한 언어 독립적 정의를 사용합니다. 이 정의는 여러 상황에서 작동하지만, 축약과 소유의 아포스트로피가 단어 경계를 형성한다는 것을 의미하고, 이는 원하는 결과가 아닐 수도 있습니다:

>>> b"they're bill's friends from the UK".title()
b"They'Re Bill'S Friends From The Uk"

정규식을 사용하여 아포스트로피에 대한 해결 방법을 구성할 수 있습니다:

>>> import re
>>> def titlecase(s):
...     return re.sub(rb"[A-Za-z]+('[A-Za-z]+)?",
...                   lambda mo: mo.group(0)[0:1].upper() +
...                              mo.group(0)[1:].lower(),
...                   s)
...
>>> titlecase(b"they're bill's friends.")
b"They're Bill's Friends."

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.upper()

bytearray.upper()

모든 ASCII 소문자를 해당 대문자로 변환한 시퀀스의 복사본을 돌려줍니다.

예를 들면:

>>> b'Hello World'.upper()
b'HELLO WORLD'

ASCII 소문자는 시퀀스 b'abcdefghijklmnopqrstuvwxyz' 에 있는 바이트 값입니다. ASCII 대문자는, 시퀀스 b'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 에 있는 바이트 값입니다.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

bytes.zfill(width)

bytearray.zfill(width)

길이가 width 인 시퀀스를 만들기 위해 ASCII b'0' 문자를 왼쪽에 채운 시퀀스의 복사본을 돌려줍니다. 선행 부호 접두어(b'+'/b'-')는 부호 문자의 앞이 아니라 뒤 에 채우는 것으로 처리됩니다. bytes 객체의 경우, width 가 len(s) 보다 작거나 같은 경우 원래 시퀀스를 돌려줍니다.

예를 들면:

>>> b"42".zfill(5)
b'00042'
>>> b"-42".zfill(5)
b'-0042'

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

printf 스타일 바이너리 포매팅

참고

여기에 설명된 포맷 연산은 여러 가지 일반적인 오류를 (예를 들어 튜플과 딕셔너리를 올바르게 표시하지 못하는 것) 유발하는 다양한 문제점들이 있습니다. 인쇄될 값이 튜플 또는 딕셔너리일 경우 튜플로 감싸야 합니다.

바이너리 시퀀스 객체는 한가지 고유한 내장 연산을 갖고 있습니다: % 연산자 (모듈로). 이것은 바이너리 포매팅 또는 치환 연산자라고도 합니다. format % values 가 주어질 때 (format 은 바이너리 시퀀스입니다), format 내부의 % 변환 명세는 0개 이상의 values 의 요소로 대체됩니다. 이 효과는 C 언어에서 sprintf()를 사용하는 것과 비슷합니다.

format 이 하나의 인자를 요구하면, values 는 하나의 비 튜플 객체 일 수 있습니다. [5] 그렇지 않으면, values 는 format 바이너리 시퀀스 객체가 지정하는 항목의 수와 같은 튜플이거나 단일 매핑 객체 (예를 들어, 딕셔너리) 여야 합니다.

변환 명세는 두 개 이상의 문자를 포함하며 다음과 같은 구성 요소들을 포함하는데, 반드시 이 순서대로 나와야 합니다:

'%' 문자: 명세의 시작을 나타냅니다.

매핑 키 (선택 사항): 괄호로 둘러싸인 문자들의 시퀀스로 구성됩니다 (예를 들어, (somename)).

변환 플래그 (선택 사항): 일부 변환 유형의 결과에 영향을 줍니다.

최소 필드 폭 (선택 사항): '*' (애스터리스크) 로 지정하면, 실제 폭은 values 튜플의 다음 요소에서 읽히고, 변환할 객체는 최소 필드 폭과 선택적 정밀도 뒤에 옵니다.

정밀도 (선택 사항): '.' (점) 다음에 정밀도가 옵니다. '*' (애스터리스크) 로 지정하면, 실제 정밀도는 values 튜플의 다음 요소에서 읽히고, 변환할 값은 정밀도 뒤에 옵니다.

길이 수정자 (선택 사항).

변환 유형.

오른쪽 인자가 딕셔너리 (또는 다른 매핑 형) 인 경우, 바이너리 시퀀스 객체에 있는 변환 명세는 반드시 '%' 문자 바로 뒤에 그 딕셔너리의 매핑 키를 괄호로 둘러싼 형태로 포함해야 합니다. 매핑 키는 포맷할 값을 매핑으로 부터 선택합니다. 예를 들어:

>>> print(b'%(language)s has %(number)03d quote types.' %
...       {b'language': b"Python", b"number": 2})
b'Python has 002 quote types.'

이 경우 * 지정자를 사용할 수 없습니다 (순차적인 매개변수 목록이 필요하기 때문입니다).

변환 플래그 문자는 다음과 같습니다:

플래그

뜻

'#'

값 변환에 “대체 형식” (아래에 정의되어있습니다) 을 사용합니다.

'0'

변환은 숫자 값의 경우 0으로 채웁니다.

'-'

변환된 값은 왼쪽으로 정렬됩니다 (둘 다 주어지면 '0' 변환보다 우선 합니다).

' '

(스페이스) 부호 있는 변환 때문에 만들어진 양수 앞에 빈칸을 남겨둡니다 (음수면 빈 문자열입니다).

'+'

부호 문자 ('+' or '-') 가 변환 앞에 놓입니다 (' ' 플래그에 우선합니다).

길이 수정자 (h, l, L) 를 제공할 수는 있지만, 파이썬에서 필요하지 않기 때문에 무시됩니다 – 예를 들어 %ld 는 %d 와 같습니다.

변환 유형은 다음과 같습니다:

변환

뜻

노트

'd'

부호 있는 정수 십진 표기.

'i'

부호 있는 정수 십진 표기.

'o'

부호 있는 8진수 값.

(1)

'u'

쓸데없는 유형 – 'd' 와 같습니다.

(8)

'x'

부호 있는 16진수 (소문자).

(2)

'X'

부호 있는 16진수 (대문자).

(2)

'e'

Floating-point exponential format (lowercase).

(3)

'E'

Floating-point exponential format (uppercase).

(3)

'f'

Floating-point decimal format.

(3)

'F'

Floating-point decimal format.

(3)

'g'

Floating-point format. Uses lowercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.

(4)

'G'

Floating-point format. Uses uppercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.

(4)

'c'

단일 바이트 (정수 또는 길이 1인 바이너리 시퀀스를 허용합니다).

'b'

Bytes (any object that follows the buffer protocol or has __bytes__()).

(5)

's'

's' 는 'b' 의 별칭이고 파이썬 2/3에서만 사용되어야 합니다.

(6)

'a'

Bytes (converts any Python object using repr(obj).encode('ascii', 'backslashreplace')).

(5)

'r'

'r' 는 'a' 의 별칭이고 파이썬 2/3에서만 사용되어야 합니다.

(7)

'%'

인자는 변환되지 않고, 결과에 '%' 문자가 표시됩니다.

노트:

대체 형식은 첫 번째 숫자 앞에 선행 8진수 지정자 ('0o')를 삽입합니다.

대체 형식은 첫 번째 숫자 앞에 선행 '0x' 또는 '0X' ('x' 나 'X' 유형 중 어느 것을 사용하느냐에 따라 달라집니다) 를 삽입합니다.

대체 형식은 그 뒤에 숫자가 나오지 않더라도 항상 소수점을 포함합니다.

정밀도는 소수점 이하 자릿수를 결정하며 기본값은 6입니다.

대체 형식은 결과에 항상 소수점을 포함하고 뒤에 오는 0은 제거되지 않습니다.

정밀도는 소수점 앞뒤의 유효 자릿수를 결정하며 기본값은 6입니다.

정밀도가 N 이라면, 출력은 N 문자로 잘립니다.

b'%s' 는 폐지되었습니다. 하지만 3.x 시리즈에서는 제거되지 않습니다.

b'%r' 는 폐지되었습니다. 하지만 3.x 시리즈에서는 제거되지 않습니다.

PEP 237 [https://peps.python.org/pep-0237/]을 참조하세요.

참고

이 메서드의 바이트 배열 버전은 제자리에서 동작하지 않습니다 - 변경되지 않는 경우조차 항상 새 객체를 만듭니다.

더 보기

PEP 461 [https://peps.python.org/pep-0461/] - bytes와 bytearray에 % 포매팅 추가

Added in version 3.5.

메모리 뷰

memoryview 객체는 파이썬 코드가 버퍼 프로토콜 을 지원하는 객체의 내부 데이터에 복사 없이 접근할 수 있게 합니다.

class memoryview(object)

Create a memoryview that references object. object must support the buffer protocol. Built-in objects that support the buffer protocol include bytes and bytearray.

A memoryview has the notion of an element, which is the atomic memory unit handled by the originating object. For many simple types such as bytes and bytearray, an element is a single byte, but other types such as array.array may have bigger elements.

len(view) is equal to the length of tolist, which is the nested list representation of the view. If view.ndim = 1, this is equal to the number of elements in the view.

버전 3.12에서 변경: If view.ndim == 0, len(view) now raises TypeError instead of returning 1.

The itemsize attribute will give you the number of bytes in a single element.

memoryview 는 슬라이싱과 인덱싱을 지원하여 데이터를 노출합니다. 일차원 슬라이스는 서브 뷰를 만듭니다:

>>> v = memoryview(b'abcefg')
>>> v[1]
98
>>> v[-1]
103
>>> v[1:4]
<memory at 0x7f3ddc9f4350>
>>> bytes(v[1:4])
b'bce'

format 이 struct 모듈의 네이티브 형식 지정자 중 하나인 경우, 정수 또는 정수의 튜플을 사용하는 인덱싱도 지원되며 올바른 형으로 하나의 요소를 돌려줍니다. 일차원 메모리 뷰는 정수 또는 하나의 정수를 갖는 튜플로 인덱싱 할 수 있습니다. 다차원 메모리 뷰는 정확히 ndim 개의 정수를 갖는 튜플로 인덱싱할 수 있습니다. 여기서 ndim 은 차원 수입니다. 영차원 메모리 뷰는 빈 튜플로 인덱싱할 수 있습니다.

다음은 바이트가 아닌 형식의 예입니다:

>>> import array
>>> a = array.array('l', [-11111111, 22222222, -33333333, 44444444])
>>> m = memoryview(a)
>>> m[0]
-11111111
>>> m[-1]
44444444
>>> m[::2].tolist()
[-11111111, -33333333]

하부 객체가 쓰기 가능하면, 메모리 뷰는 일차원 슬라이스 대입을 지원합니다. 크기 변경은 허용되지 않습니다:

>>> data = bytearray(b'abcefg')
>>> v = memoryview(data)
>>> v.readonly
False
>>> v[0] = ord(b'z')
>>> data
bytearray(b'zbcefg')
>>> v[1:4] = b'123'
>>> data
bytearray(b'z123fg')
>>> v[2:3] = b'spam'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview assignment: lvalue and rvalue have different structures
>>> v[2:6] = b'spam'
>>> data
bytearray(b'z1spam')

One-dimensional memoryviews of hashable (read-only) types with formats ‘B’, ‘b’ or ‘c’ are also hashable. The hash is defined as hash(m) == hash(m.tobytes()):

>>> v = memoryview(b'abcefg')
>>> hash(v) == hash(b'abcefg')
True
>>> hash(v[2:4]) == hash(b'ce')
True
>>> hash(v[::-2]) == hash(b'abcefg'[::-2])
True

버전 3.3에서 변경: One-dimensional memoryviews can now be sliced. One-dimensional memoryviews with formats ‘B’, ‘b’ or ‘c’ are now hashable.

버전 3.4에서 변경: 이제 메모리 뷰는 자동으로 collections.abc.Sequence 로 등록됩니다

버전 3.5에서 변경: 이제 메모리 뷰는 정수의 튜플로 인덱싱될 수 있습니다.

버전 3.14에서 변경: memoryview is now a generic type.

memoryview 는 몇 가지 메서드를 가지고 있습니다:

__eq__(exporter)

메모리 뷰와 PEP 3118 [https://peps.python.org/pep-3118/] 제공자(exporter)는 다음과 같은 조건을 만족할 때 같다고 비교됩니다: 모양이 동등하고 피연산자의 각 형식 코드가 struct 문법을 사용하여 해석될 때 모든 해당 값이 같다.

현재 tolist() 가 지원하는 struct 형식 문자열의 부분 집합의 경우, v.tolist() == w.tolist() 면 v 와 w 는 같습니다:

>>> import array
>>> a = array.array('I', [1, 2, 3, 4, 5])
>>> b = array.array('d', [1.0, 2.0, 3.0, 4.0, 5.0])
>>> c = array.array('b', [5, 3, 1])
>>> x = memoryview(a)
>>> y = memoryview(b)
>>> x == a == y == b
True
>>> x.tolist() == a.tolist() == y.tolist() == b.tolist()
True
>>> z = y[::-2]
>>> z == c
True
>>> z.tolist() == c.tolist()
True

형식 문자열이 struct 모듈에서 지원되지 않으면 객체는 항상 같지 않다고 비교됩니다 (형식 문자열과 버퍼 내용이 같더라도 그렇습니다):

>>> from ctypes import BigEndianStructure, c_long
>>> class BEPoint(BigEndianStructure):
...     _fields_ = [("x", c_long), ("y", c_long)]
...
>>> point = BEPoint(100, 200)
>>> a = memoryview(point)
>>> b = memoryview(point)
>>> a == point
False
>>> a == b
False

Note that, as with floating-point numbers, v is w does not imply v == w for memoryview objects.

버전 3.3에서 변경: 이전 버전에서는 항목 형식과 논리 배열 구조를 무시하고 원시 메모리를 비교했습니다.

tobytes(order='C')

버퍼의 데이터를 바이트열로 돌려줍니다. 이는 메모리 뷰에 bytes 생성자를 호출하는 것과 동등합니다.

>>> m = memoryview(b"abc")
>>> m.tobytes()
b'abc'
>>> bytes(m)
b'abc'

불연속 배열의 경우 결과는 모든 요소를 바이트로 변환하여 평평한 리스트로 만든 것과 같습니다. tobytes() 는 struct 모듈 문법에 없는 것을 포함하여 모든 형식 문자열을 지원합니다.

Added in version 3.8: order는 {‘C’, ‘F’, ‘A’} 일 수 있습니다. order가 ‘C’ 나 ‘F’ 이면, 원래 배열의 데이터가 C 나 포트란 순서로 변환됩니다. 연속 뷰의 경우, ‘A’ 는 물리적 메모리의 정확한 사본을 반환합니다. 특히, 메모리 내 포트란 순서가 보존됩니다. 연속적이지 않은 뷰의 경우, 데이터는 먼저 C로 변환됩니다. order=None은 order=’C’와 같습니다.

hex([sep[, bytes_per_sep]])

버퍼 내의 각 바이트를 두 개의 16진수로 표현한 문자열 객체를 돌려줍니다.

>>> m = memoryview(b"abc")
>>> m.hex()
'616263'

Added in version 3.5.

버전 3.8에서 변경: bytes.hex()와 비슷하게, 이제 memoryview.hex()는 16진수 출력의 바이트 사이에 구분 기호를 삽입하기 위해 선택적 sep과 bytes_per_sep 매개 변수를 지원합니다.

tolist()

버퍼 내의 데이터를 요소들의 리스트로 돌려줍니다.

>>> memoryview(b'abc').tolist()
[97, 98, 99]
>>> import array
>>> a = array.array('d', [1.1, 2.2, 3.3])
>>> m = memoryview(a)
>>> m.tolist()
[1.1, 2.2, 3.3]

버전 3.3에서 변경: tolist() 는 이제 struct 모듈 문법의 모든 단일 문자 네이티브 형식과 다차원 표현을 지원합니다.

toreadonly()

메모리 뷰 객체의 읽기 전용 버전을 반환합니다. 원래 메모리 뷰 객체는 변경되지 않습니다.

>>> m = memoryview(bytearray(b'abc'))
>>> mm = m.toreadonly()
>>> mm.tolist()
[97, 98, 99]
>>> mm[0] = 42
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot modify read-only memory
>>> m[0] = 43
>>> mm.tolist()
[43, 98, 99]

Added in version 3.8.

release()

메모리 뷰 객체에 의해 노출된 하부 버퍼를 해제합니다. 많은 객체는 뷰가 그 객체에 연결될 때 특별한 조처를 합니다 (예를 들어, bytearray 는 일시적으로 크기 조절을 금지합니다); 따라서, release()를 호출하면 가능한 한 빨리 이 제한 사항을 제거하고 붙잡힌 자원을 해제할 수 있습니다.

After this method has been called, any further operation on the view raises a ValueError (except release() itself which can be called multiple times):

>>> m = memoryview(b'abc')
>>> m.release()
>>> m[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: operation forbidden on released memoryview object

with 문을 사용한 컨텍스트 관리 프로토콜은 비슷한 효과를 낼 수 있습니다:

>>> with memoryview(b'abc') as m:
...     m[0]
...
97
>>> m[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: operation forbidden on released memoryview object

Added in version 3.2.

cast(format[, shape])

메모리 뷰를 새로운 형식이나 모양으로 캐스팅합니다. shape 의 기본값은 [byte_length//new_itemsize] 인데, 결과 뷰가 일차원이 된다는 의미입니다. 반환 값은 새로운 메모리 뷰이지만 버퍼 자체는 복사되지 않습니다. 지원되는 캐스팅은 1D -> C-연속 과 C-연속 -> 1D입니다.

The destination format is restricted to a single element native format in struct syntax. One of the formats must be a byte format (‘B’, ‘b’ or ‘c’). The byte length of the result must be the same as the original length. Note that all byte lengths may depend on the operating system.

1D/long 을 1D/unsigned bytes 로 캐스트:

>>> import array
>>> a = array.array('l', [1,2,3])
>>> x = memoryview(a)
>>> x.format
'l'
>>> x.itemsize
8
>>> len(x)
3
>>> x.nbytes
24
>>> y = x.cast('B')
>>> y.format
'B'
>>> y.itemsize
1
>>> len(y)
24
>>> y.nbytes
24

1D/unsigned bytes 를 1D/char 로 캐스트:

>>> b = bytearray(b'zyz')
>>> x = memoryview(b)
>>> x[0] = b'a'
Traceback (most recent call last):
  ...
TypeError: memoryview: invalid type for format 'B'
>>> y = x.cast('c')
>>> y[0] = b'a'
>>> b
bytearray(b'ayz')

1D/bytes 를 3D/ints 로 캐스트 한 후 다시 1D/signed char 로 캐스트:

>>> import struct
>>> buf = struct.pack("i"*12, *list(range(12)))
>>> x = memoryview(buf)
>>> y = x.cast('i', shape=[2,2,3])
>>> y.tolist()
[[[0, 1, 2], [3, 4, 5]], [[6, 7, 8], [9, 10, 11]]]
>>> y.format
'i'
>>> y.itemsize
4
>>> len(y)
2
>>> y.nbytes
48
>>> z = y.cast('b')
>>> z.format
'b'
>>> z.itemsize
1
>>> len(z)
48
>>> z.nbytes
48

1D/unsigned long 을 2D/unsigned long 으로 캐스트:

>>> buf = struct.pack("L"*6, *list(range(6)))
>>> x = memoryview(buf)
>>> y = x.cast('L', shape=[2,3])
>>> len(y)
2
>>> y.nbytes
48
>>> y.tolist()
[[0, 1, 2], [3, 4, 5]]

Added in version 3.3.

버전 3.5에서 변경: 바이트 형식으로 변환할 때 소스 형식이 더는 제한되지 않습니다.

몇 가지 읽기 전용 어트리뷰트도 사용할 수 있습니다:

obj

메모리 뷰의 하부 객체:

>>> b  = bytearray(b'xyz')
>>> m = memoryview(b)
>>> m.obj is b
True

Added in version 3.3.

nbytes

nbytes == product(shape) * itemsize == len(m.tobytes()). 배열이 연속적일 때 차지하게 될 바이트 수입니다. 꼭 len(m)과 같을 필요는 없습니다:

>>> import array
>>> a = array.array('i', [1,2,3,4,5])
>>> m = memoryview(a)
>>> len(m)
5
>>> m.nbytes
20
>>> y = m[::2]
>>> len(y)
3
>>> y.nbytes
12
>>> len(y.tobytes())
12

다차원 배열:

>>> import struct
>>> buf = struct.pack("d"*12, *[1.5*x for x in range(12)])
>>> x = memoryview(buf)
>>> y = x.cast('d', shape=[3,4])
>>> y.tolist()
[[0.0, 1.5, 3.0, 4.5], [6.0, 7.5, 9.0, 10.5], [12.0, 13.5, 15.0, 16.5]]
>>> len(y)
3
>>> y.nbytes
96

Added in version 3.3.

readonly

메모리가 읽기 전용인지 여부를 나타내는 논리값.

format

뷰의 각 요소에 대한 형식(struct 모듈 스타일)을 포함하는 문자열입니다. 메모리 뷰는 제공자로부터 임의의 형식 문자열로 만들어질 수 있지만, 일부 메서드(예, tolist())는 원시 네이티브 단일 요소 형식으로 제한됩니다.

버전 3.3에서 변경: 'B' 형식은 이제 struct 모듈 문법에 따라 처리됩니다. 이것은 memoryview(b'abc')[0] == b'abc'[0] == 97 이 됨을 의미합니다.

itemsize

메모리 뷰 각 요소의 크기 (바이트):

>>> import array, struct
>>> m = memoryview(array.array('H', [32000, 32001, 32002]))
>>> m.itemsize
2
>>> m[0]
32000
>>> struct.calcsize('H') == m.itemsize
True

ndim

메모리가 나타내는 다차원 배열의 차원 수를 나타내는 정수.

shape

N-차원 배열로서의 메모리의 모양을 가리키는, 길이 ndim 인 정수의 튜플입니다.

버전 3.3에서 변경: ndim = 0 일 때 None 대신 빈 튜플을 제공합니다.

strides

배열의 각 차원에 대해 각 요소를 참조하는데 필요한 바이트 수를 제공하는, 길이 ndim 인 정수의 튜플입니다.

버전 3.3에서 변경: ndim = 0 일 때 None 대신 빈 튜플을 제공합니다.

suboffsets

PIL 스타일 배열에 내부적으로 사용됩니다. 값은 정보 제공용입니다.

c_contiguous

메모리가 C-연속 인지를 나타내는 논리값.

Added in version 3.3.

f_contiguous

메모리가 포트란 연속 인지를 나타내는 논리값.

Added in version 3.3.

contiguous

메모리가 연속 인지를 나타내는 논리값.

Added in version 3.3.

집합 형 — set, frozenset

집합 (set) 객체는 서로 다른 해시 가능 객체의 순서 없는 컬렉션입니다. 일반적인 용도는 멤버십 검사, 시퀀스에서 중복 제거와 교집합, 합집합, 차집합, 대칭 차집합과 같은 수학 연산을 계산하는 것입니다. (다른 컨테이너들은 내장 dict, list, tuple 클래스 및 collections 모듈을 참조하십시오.)

다른 컬렉션과 마찬가지로, 집합은 x in set, len(set), for x in set 을 지원합니다. 순서가 없는 컬렉션이므로, 집합은 원소의 위치나 삽입 순서를 기록하지 않습니다. 따라서 집합은 인덱싱, 슬라이싱 또는 기타 시퀀스와 유사한 동작을 지원하지 않습니다.

현재 두 가지 내장형이 있습니다, set과 frozenset. set 형은 가변입니다 — 내용을 add() 나 remove() 와 같은 메서드를 사용하여 변경할 수 있습니다. 가변이기 때문에, 해시값이 없으며 딕셔너리 키 또는 다른 집합의 원소로 사용할 수 없습니다. frozenset 형은 불변이고 해시 가능 합니다 — 만들어진 후에는 내용을 바꿀 수 없습니다; 따라서 딕셔너리 키 또는 다른 집합의 원소로 사용할 수 있습니다.

비어 있지 않은 set은 (frozenset 은 아닙니다) set 생성자뿐만 아니라 중괄호 안에 쉼표로 구분된 원소 목록을 넣어서 만들 수 있습니다, 예를 들어: {'jack', 'sjoerd'}.

두 클래스의 생성자는 같게 작동합니다:

class set([iterable])

class frozenset([iterable])

iterable 에서 요소를 취하는 새 set 또는 frozenset 객체를 돌려줍니다. 집합의 원소는 반드시 해시 가능 해야 합니다. 집합의 집합을 표현하려면, 포함되는 집합은 반드시 frozenset 객체여야 합니다. iterable 을 지정하지 않으면 새 빈 집합을 돌려줍니다.

집합은 여러 가지 방법으로 만들 수 있습니다:

중괄호 안에 쉼표로 구분된 요소 나열하기: {'jack', 'sjoerd'}

집합 컴프리헨션 사용하기: {c for c in 'abracadabra' if c not in 'abc'}

형 생성자 사용하기: set(), set('foobar'), set(['a', 'b', 'foo'])

set과 frozenset 의 인스턴스는 다음과 같은 연산을 제공합니다:

len(s)

집합 s 의 원소 수(s 의 크기)를 돌려줍니다.

x in s

s 에 대해 x 의 멤버십을 검사합니다.

x not in s

s 에 대해 x 의 비 멤버십을 검사합니다.

isdisjoint(other)

집합이 other 와 공통 원소를 갖지 않는 경우 True 을 돌려줍니다. 집합은 교집합이 공집합일 때, 그리고 그때만 서로소(disjoint)라고 합니다.

issubset(other)

set <= other

집합의 모든 원소가 other 에 포함되는지 검사합니다.

set < other

집합이 other 의 진부분집합인지 검사합니다, 즉, set <= other and set != other.

issuperset(other)

set >= other

other 의 모든 원소가 집합에 포함되는지 검사합니다.

set > other

집합이 other 의 진상위집합인지 검사합니다, 즉, set >= other and set != other.

union(*others)

set | other | ...

집합과 모든 others에 있는 원소들로 구성된 새 집합을 돌려줍니다.

intersection(*others)

set & other & ...

집합과 모든 others의 공통 원소들로 구성된 새 집합을 돌려줍니다.

difference(*others)

set - other - ...

집합에는 포함되었으나 others에는 포함되지 않은 원소들로 구성된 새 집합을 돌려줍니다.

symmetric_difference(other)

set ^ other

집합이나 other에 포함되어 있으나 둘 모두에 포함되지는 않은 원소들로 구성된 새 집합을 돌려줍니다.

copy()

집합의 얕은 복사본을 돌려줍니다.

Note, the non-operator versions of union(), intersection(), difference(), symmetric_difference(), issubset(), and issuperset() methods will accept any iterable as an argument. In contrast, their operator based counterparts require their arguments to be sets. This precludes error-prone constructions like set('abc') & 'cbs' in favor of the more readable set('abc').intersection('cbs').

set과 frozenset 모두 집합 간의 비교를 지원합니다. 두 집합은 각 집합의 모든 원소가 다른 집합에 포함되어있는 경우에만 같습니다 (서로 다른 집합의 부분집합입니다). 집합이 다른 집합의 진부분집합(부분집합이지만 같지는 않은 경우)일 때만 첫 번째 집합이 두 번째 집합보다 작습니다. 집합이 다른 집합의 진상위집합(상위집합이지만 같지는 않은 경우)일 때만 첫 번째 집합이 두 번째 집합보다 큽니다.

set 의 인스턴스는 그 원소를 기반으로 frozenset 의 인스턴스와 비교됩니다. 예를 들어, set('abc') == frozenset('abc') 는 True 를 돌려주고 set('abc') in set([frozenset('abc')]) 도 마찬가지입니다.

부분 집합 및 동등 비교는 전 순서(total ordering) 함수로 일반화되지 않습니다. 예를 들어, 비어 있지 않은 두 개의 서로소인 집합은 같지 않고 서로의 부분 집합이 아닙니다, 그래서 다음은 모두 False 를 돌려줍니다: a<b, a==b, a>b.

집합은 부분 순서(부분 집합 관계)만 정의하기 때문에, 집합의 리스트에 대한 list.sort() 메서드의 결과는 정의되지 않습니다.

딕셔너리 키처럼, 집합의 원소는 반드시 해시 가능 해야 합니다.

set 인스턴스와 frozenset 을 혼합 한 이항 연산은 첫 번째 피연산자의 형을 돌려줍니다. 예를 들어: frozenset('ab') | set('bc') 는 frozenset 의 인스턴스를 돌려줍니다.

다음 표는 frozenset 의 불변 인스턴스에는 적용되지 않고 set 에서만 사용할 수 있는 연산들을 나열합니다:

update(*others)

set |= other | ...

집합을 갱신해서, 모든 others의 원소들을 더합니다.

intersection_update(*others)

set &= other & ...

집합을 갱신해서, 그 집합과 others에 공통으로 포함된 원소들만 남깁니다.

difference_update(*others)

set -= other | ...

집합을 갱신해서, others에 있는 원소들을 제거합니다.

symmetric_difference_update(other)

set ^= other

집합을 갱신해서, 두 집합의 어느 한 곳에만 포함된 원소들만 남깁니다.

add(elem)

원소 elem 을 집합에 추가합니다.

remove(elem)

원소 elem 을 집합에서 제거합니다. elem 가 집합에 포함되어 있지 않으면 KeyError 를 일으킵니다.

discard(elem)

원소 elem 이 집합에 포함되어 있으면 제거합니다.

pop()

집합으로부터 임의의 원소를 제거해 돌려줍니다. 집합이 비어있는 경우 KeyError 를 일으킵니다.

clear()

집합의 모든 원소를 제거합니다.

참고로, update(), intersection_update(), difference_update(), symmetric_difference_update() 메서드의 비 연산자 버전은 임의의 이터러블을 인자로 받아들입니다.

Note, the elem argument to the __contains__(), remove(), and discard() methods may be a set. To support searching for an equivalent frozenset, a temporary one is created from elem.

매핑 형 — dict

매핑 객체는 해시 가능 값을 임의의 객체에 대응합니다. 매핑은 가변 객체입니다. 현재 오직 하나의 표준 매핑 형이 있습니다, 딕셔너리 (dictionary). (다른 컨테이너들은 내장 list, set, tuple 클래스 및 collections 모듈을 참조하십시오.)

A dictionary’s keys are almost arbitrary values. Values that are not hashable, that is, values containing lists, dictionaries or other mutable types (that are compared by value rather than by object identity) may not be used as keys. Values that compare equal (such as 1, 1.0, and True) can be used interchangeably to index the same dictionary entry.

class dict(**kwargs)

class dict(mapping, **kwargs)

class dict(iterable, **kwargs)

선택적 위치 인자와 (비어있을 수 있는) 키워드 인자들의 집합으로부터 초기화된 새 딕셔너리를 돌려줍니다.

딕셔너리는 여러 가지 방법으로 만들 수 있습니다:

중괄호 안에 쉼표로 구분된 key: value 쌍을 나열하기: {'jack': 4098, 'sjoerd': 4127} 또는 {4098: 'jack', 4127: 'sjoerd'}

딕셔너리 컴프리헨션 사용하기: {}, {x: x ** 2 for x in range(10)}

형 생성자 사용하기: dict(), dict([('foo', 100), ('bar', 200)]), dict(foo=100, bar=200)

If no positional argument is given, an empty dictionary is created. If a positional argument is given and it defines a keys() method, a dictionary is created by calling __getitem__() on the argument with each returned key from the method. Otherwise, the positional argument must be an iterable object. Each item in the iterable must itself be an iterable with exactly two elements. The first element of each item becomes a key in the new dictionary, and the second element the corresponding value. If a key occurs more than once, the last value for that key becomes the corresponding value in the new dictionary.

키워드 인자가 제공되면, 키워드 인자와 해당 값이 위치 인자로부터 만들어진 딕셔너리에 추가됩니다. 추가되는 키가 이미 존재하면, 키워드 인자에서 온 값이 위치 인자에게서 온 값을 대체합니다.

예를 들어, 다음 예제는 모두 {"one": 1, "two": 2, "three": 3} 와 같은 딕셔너리를 돌려줍니다:

>>> a = dict(one=1, two=2, three=3)
>>> b = {'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({'three': 3, 'one': 1, 'two': 2})
>>> f = dict({'one': 1, 'three': 3}, two=2)
>>> a == b == c == d == e == f
True

첫 번째 예제에서와같이 키워드 인자는 유효한 파이썬 식별자인 키에 대해서만 작동합니다. 그 외의 경우는 모든 유효한 키를 사용할 수 있습니다.

이것들은 딕셔너리가 지원하는 연산들입니다 (그러므로, 사용자 정의 매핑 형도 지원해야 합니다):

list(d)

딕셔너리 d 에 사용된 모든 키의 리스트를 돌려줍니다.

len(d)

딕셔너리 d 에 있는 항목의 수를 돌려줍니다.

d[key]

키 key 인 d 의 항목을 돌려줍니다. key 가 매핑에 없는 경우 KeyError 를 일으킵니다.

dict 의 서브 클래스가 method __missing__() 을 정의하고 key 가 존재하지 않는다면, d[key] 연산은 키 key 를 인자로 하여 그 메서드를 호출합니다. 그런 다음 d[key] 연산은 __missing__(key) 호출이 반환한 값이나 일으킨 예외를 그대로 반환하거나 일으킵니다. 다른 연산이나 메서드는 __missing__() 을 호출하지 않습니다. __missing__() 이 정의되어 있지 않으면 KeyError 를 일으킵니다. __missing__() 은 메서드 여야 합니다; 인스턴스 변수가 될 수 없습니다:

>>> class Counter(dict):
...     def __missing__(self, key):
...         return 0
...
>>> c = Counter()
>>> c['red']
0
>>> c['red'] += 1
>>> c['red']
1

위의 예는 collections.Counter 구현 일부를 보여줍니다. 다른 __missing__ 메서드가 collections.defaultdict 에서 사용됩니다.

d[key] = value

d[key] 를 value 로 설정합니다.

del d[key]

d 에서 d[key] 를 제거합니다. key 가 매핑에 없는 경우 KeyError 를 일으킵니다.

key in d

d 에 키 key 가 있으면 True 를, 그렇지 않으면 False 를 돌려줍니다.

key not in d

not key in d 와 동등합니다.

iter(d)

딕셔너리의 키에 대한 이터레이터를 돌려줍니다. 이것은 iter(d.keys()) 의 단축입니다.

clear()

딕셔너리에서 모든 항목을 제거합니다.

copy()

딕셔너리의 얕은 복사본을 돌려줍니다.

classmethod fromkeys(iterable, value=None, /)

iterable 이 제공하는 값들을 키로 사용하고 모든 값을 value 로 설정한 새 딕셔러리를 돌려줍니다.

fromkeys() 는 새로운 딕셔너리를 돌려주는 클래스 메서드입니다. value 의 기본값은 None 입니다. 모든 값이 단일 인스턴스를 참조하므로, value가 빈 목록과 같은 가변 객체가 되는 것은 일반적으로 의미가 없습니다. 별개의 값을 얻으려면, 대신 딕셔너리 컴프리헨션을 사용하십시오.

get(key, default=None)

key 가 딕셔너리에 있는 경우 key 에 대응하는 값을 돌려주고, 그렇지 않으면 default 를 돌려줍니다. default 가 주어지지 않으면 기본값 None 이 사용됩니다. 그래서 이 메서드는 절대로 KeyError 를 일으키지 않습니다.

items()

딕셔너리 항목들((key, value) 쌍들)의 새 뷰를 돌려줍니다. 뷰 객체의 설명서 을 참조하세요.

keys()

딕셔너리 키들의 새 뷰를 돌려줍니다. 뷰 객체의 설명서 을 참조하세요.

pop(key[, default])

key 가 딕셔너리에 있으면 제거하고 그 값을 돌려줍니다. 그렇지 않으면 default 를 돌려줍니다. default 가 주어지지 않고 key 가 딕셔너리에 없으면 KeyError 를 일으킵니다.

popitem()

딕셔너리에서 (key, value) 쌍을 제거하고 돌려줍니다. 쌍은 LIFO 순서로 반환됩니다.

popitem() 은 집합 알고리즘에서 종종 사용되듯이 딕셔너리를 파괴적으로 이터레이션 하는 데 유용합니다. 딕셔너리가 비어 있으면 popitem() 호출은 KeyError 를 일으킵니다.

버전 3.7에서 변경: 이제 LIFO 순서가 보장됩니다. 이전 버전에서는, popitem()가 임의의 키/값 쌍을 반환합니다.

reversed(d)

딕셔너리의 키에 대한 역순 이터레이터를 돌려줍니다. 이것은 reversed(d.keys()) 의 단축입니다.

Added in version 3.8.

setdefault(key, default=None)

key 가 딕셔너리에 있으면 해당 값을 돌려줍니다. 그렇지 않으면, default 값을 갖는 key 를 삽입한 후 default 를 돌려줍니다. default 의 기본값은 None 입니다.

update([other])

other 가 제공하는 키/값 쌍으로 사전을 갱신합니다. 기존 키는 덮어씁니다. None 을 돌려줍니다.

update() accepts either another object with a keys() method (in which case __getitem__() is called with every key returned from the method) or an iterable of key/value pairs (as tuples or other iterables of length two). If keyword arguments are specified, the dictionary is then updated with those key/value pairs: d.update(red=1, blue=2).

values()

딕셔너리 값들의 새 뷰를 돌려줍니다. 뷰 객체의 설명서 을 참조하세요.

한 dict.values() 뷰와 다른 dict.values() 뷰 간의 동등 비교는 항상 False를 반환합니다. 이것은 dict.values()를 자신과 비교할 때도 적용됩니다:

>>> d = {'a': 1}
>>> d.values() == d.values()
False

d | other

d와 other의 병합된 키와 값으로 새 딕셔너리를 만듭니다. 둘 다 딕셔너리이어야 합니다. d와 other가 키를 공유하면 other의 값이 우선합니다.

Added in version 3.9.

d |= other

other의 키와 값으로 딕셔너리 d를 갱신합니다. other는 매핑이나 키/값 쌍의 이터러블일 수 있습니다. d와 other가 키를 공유하면 other의 값이 우선합니다.

Added in version 3.9.

딕셔너리는 (순서와 관계없이) 같은 (key, value) 쌍들을 가질 때, 그리고 그때만 같다고 비교됩니다. 순서 비교(‘<’, ‘<=’, ‘>=’, ‘>’)는 TypeError 를 일으킵니다.

딕셔너리는 삽입 순서를 유지합니다. 키를 갱신해도 순서에는 영향을 미치지 않습니다. 삭제 후에 추가된 키는 끝에 삽입됩니다.:

>>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
>>> d
{'one': 1, 'two': 2, 'three': 3, 'four': 4}
>>> list(d)
['one', 'two', 'three', 'four']
>>> list(d.values())
[1, 2, 3, 4]
>>> d["one"] = 42
>>> d
{'one': 42, 'two': 2, 'three': 3, 'four': 4}
>>> del d["two"]
>>> d["two"] = None
>>> d
{'one': 42, 'three': 3, 'four': 4, 'two': None}

버전 3.7에서 변경: 딕셔너리 순서는 삽입 순서임이 보장됩니다. 이 동작은 3.6부터 CPython의 구현 세부 사항입니다.

딕셔너리와 딕셔너리 뷰는 뒤집을 수 있습니다.

>>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
>>> d
{'one': 1, 'two': 2, 'three': 3, 'four': 4}
>>> list(reversed(d))
['four', 'three', 'two', 'one']
>>> list(reversed(d.values()))
[4, 3, 2, 1]
>>> list(reversed(d.items()))
[('four', 4), ('three', 3), ('two', 2), ('one', 1)]

버전 3.8에서 변경: 딕셔너리는 이제 뒤집을 수 있습니다.

더 보기

types.MappingProxyType 를 dict 의 읽기 전용 뷰를 만드는 데 사용할 수 있습니다.

딕셔너리 뷰 객체

dict.keys(), dict.values(), dict.items() 가 돌려주는 객체는 뷰 객체 입니다. 딕셔너리의 항목들에 대한 동적 뷰를 제공합니다. 즉, 딕셔너리가 변경되면 뷰는 이러한 변경 사항을 반영합니다.

딕셔너리 뷰는 이터레이션을 통해 각각의 데이터를 산출할 수 있고, 멤버십 검사를 지원합니다:

len(dictview)

딕셔너리에 있는 항목 수를 돌려줍니다.

iter(dictview)

딕셔너리에서 키, 값, 항목((key, value) 튜플로 표현됩니다)에 대한 이터레이터를 돌려줍니다.

키와 값은 삽입 순서로 이터레이션 됩니다. 이 때문에 zip()을 사용해서 (value, key) 쌍을 만들 수 있습니다: pairs = zip(d.values(), d.keys()). 같은 리스트를 만드는 다른 방법은 pairs = [(v, k) for (k, v) in d.items()] 입니다.

딕셔너리에 항목을 추가하거나 삭제하는 동안 뷰를 이터레이션 하면 RuntimeError 를 일으키거나 모든 항목을 이터레이션 하지 못할 수 있습니다.

버전 3.7에서 변경: 딕셔너리의 순서가 삽입 순서임이 보장됩니다.

x in dictview

x 가 하부 딕셔너리의 키, 갑, 항목에 있는 경우 True 를 돌려줍니다 (마지막의 경우 x 는 (key, value) 튜플이어야 합니다).

reversed(dictview)

딕셔너리의 키, 값 또는 항목에 대한 역방향 이터레이터를 반환합니다. 뷰는 삽입의 역순으로 이터레이트됩니다.

버전 3.8에서 변경: 딕셔너리 뷰는 이제 역 탐색할 수 있습니다.

dictview.mapping

Return a types.MappingProxyType that wraps the original dictionary to which the view refers.

Added in version 3.10.

Keys views are set-like since their entries are unique and hashable. Items views also have set-like operations since the (key, value) pairs are unique and the keys are hashable. If all values in an items view are hashable as well, then the items view can interoperate with other sets. (Values views are not treated as set-like since the entries are generally not unique.) For set-like views, all of the operations defined for the abstract base class collections.abc.Set are available (for example, ==, <, or ^). While using set operators, set-like views accept any iterable as the other operand, unlike sets which only accept sets as the input.

딕셔너리 뷰 사용의 예:

>>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, 'spam': 500}
>>> keys = dishes.keys()
>>> values = dishes.values()

>>> # iteration
>>> n = 0
>>> for val in values:
...     n += val
...
>>> print(n)
504

>>> # keys and values are iterated over in the same order (insertion order)
>>> list(keys)
['eggs', 'sausage', 'bacon', 'spam']
>>> list(values)
[2, 1, 1, 500]

>>> # view objects are dynamic and reflect dict changes
>>> del dishes['eggs']
>>> del dishes['sausage']
>>> list(keys)
['bacon', 'spam']

>>> # set operations
>>> keys & {'eggs', 'bacon', 'salad'}
{'bacon'}
>>> keys ^ {'sausage', 'juice'} == {'juice', 'sausage', 'bacon', 'spam'}
True
>>> keys | ['juice', 'juice', 'juice'] == {'bacon', 'spam', 'juice'}
True

>>> # get back a read-only proxy for the original dictionary
>>> values.mapping
mappingproxy({'bacon': 1, 'spam': 500})
>>> values.mapping['spam']
500

컨텍스트 관리자 형

파이썬의 with 문은 컨텍스트 관리자가 정의한 실행 시간 컨텍스트 개념을 지원합니다. 이는 한 쌍의 메서드를 사용해서 구현되는데, 사용자 정의 클래스가 문장 바디가 실행되기 전에 진입하고, 문장이 끝날 때 탈출하는 실행 시간 컨텍스트를 정의할 수 있게 합니다:

contextmanager.__enter__()

실행시간 컨텍스트에 진입하고 이 객체 자신이나 실행 시간 컨텍스트와 관련된 다른 객체를 돌려줍니다. 이 메서드가 돌려주는 값은, 이 컨텍스트 관리자를 사용하는 with 문의 as 절의 식별자에 연결됩니다.

자신을 돌려주는 컨텍스트 관리자의 예는 파일 객체 입니다. 파일 객체는 __enter__() 에서 자기 자신을 돌려주는데 with 문의 컨텍스트 표현식으로 open() 을 사용할 수 있도록 하기 위함입니다.

관련 객체를 돌려주는 컨텍스트 관리자의 예는 decimal.localcontext() 가 돌려주는 것입니다. 이 관리자들은 활성 십진 소수 컨텍스트를 원래 십진 소수 컨텍스트의 복사본으로 설정한 다음 복사본을 돌려줍니다. 이것은 with 문 바깥의 코드에 영향을 주지 않으면서 with 문 바디에 있는 현재 십진 소수 컨텍스트를 변경할 수 있게 합니다.

contextmanager.__exit__(exc_type, exc_val, exc_tb)

실행 시간 컨텍스트를 탈출하고 발생한 예외를 막아야 하는지를 가리키는 논리 플래그를 돌려줍니다. with 문의 바디를 실행하는 동안 예외가 발생하면, 인자에 예외 형, 값 및 추적 정보가 포함됩니다. 그렇지 않으면, 세 가지 인자 모두 None 입니다.

이 메서드에서 참 값을 돌려주면 with 문이 예외를 막고 with 문 바로 뒤에 오는 문장에서 계속 실행됩니다. 그 이외의 경우, 이 메서드의 실행이 완료된 후에 예외는 계속 퍼집니다. 이 메서드의 실행 중에 발생하는 예외는 with 문의 바디에서 발생한 모든 예외를 대체합니다.

The exception passed in should never be reraised explicitly - instead, this method should return a false value to indicate that the method completed successfully and does not want to suppress the raised exception. This allows context management code to easily detect whether or not an __exit__() method has actually failed.

파이썬은 쉬운 스레드 동기화, 파일이나 다른 객체의 신속한 닫기, 그리고 활성 십진 소수 산술 컨텍스트의 보다 간단한 조작을 지원하기 위해 몇 가지 컨텍스트 관리자를 정의합니다. 컨텍스트 관리 프로토콜의 구현을 넘어 구체적인 형은 특별히 취급되지 않습니다. 몇 가지 예제는 contextlib 모듈을 보십시오.

Python’s generators and the contextlib.contextmanager decorator provide a convenient way to implement these protocols. If a generator function is decorated with the contextlib.contextmanager decorator, it will return a context manager implementing the necessary __enter__() and __exit__() methods, rather than the iterator produced by an undecorated generator function.

파이썬/C API의 파이썬 객체에 대한 형 구조체에는 이러한 메서드들을 위해 준비된 슬롯이 없다는 점에 유의하십시오. 이러한 메서드를 정의하고자 하는 확장형은 일반적인 파이썬 액세스가 가능한 메서드로 제공해야 합니다. 실행 시간 컨텍스트를 설정하는 오버헤드와 비교할 때 한 번의 클래스 딕셔너리 조회의 오버헤드는 무시할 수 있습니다.

Type Annotation Types — Generic Alias, Union

The core built-in types for type annotations are Generic Alias and Union.

제네릭 에일리어스 형

GenericAlias objects are generally created by subscripting a class. They are most often used with container classes, such as list or dict. For example, list[int] is a GenericAlias object created by subscripting the list class with the argument int. GenericAlias objects are intended primarily for use with type annotations.

참고

It is generally only possible to subscript a class if the class implements the special method __class_getitem__().

A GenericAlias object acts as a proxy for a generic type, implementing parameterized generics.

For a container class, the argument(s) supplied to a subscription of the class may indicate the type(s) of the elements an object contains. For example, set[bytes] can be used in type annotations to signify a set in which all the elements are of type bytes.

For a class which defines __class_getitem__() but is not a container, the argument(s) supplied to a subscription of the class will often indicate the return type(s) of one or more methods defined on an object. For example, regular expressions can be used on both the str data type and the bytes data type:

If x = re.search('foo', 'foo'), x will be a re.Match object where the return values of x.group(0) and x[0] will both be of type str. We can represent this kind of object in type annotations with the GenericAlias re.Match[str].

If y = re.search(b'bar', b'bar'), (note the b for bytes), y will also be an instance of re.Match, but the return values of y.group(0) and y[0] will both be of type bytes. In type annotations, we would represent this variety of re.Match objects with re.Match[bytes].

GenericAlias objects are instances of the class types.GenericAlias, which can also be used to create GenericAlias objects directly.

T[X, Y, ...]

Creates a GenericAlias representing a type T parameterized by types X, Y, and more depending on the T used. For example, a function expecting a list containing float elements:

def average(values: list[float]) -> float:
    return sum(values) / len(values)

키 형과 값 형을 나타내는 두 개의 형 매개 변수를 기대하는 제네릭 형인 dict를 사용하는 매핑 객체의 또 다른 예. 이 예에서, 함수는 str 형의 키와 int 형의 값을 갖는 dict를 기대합니다:

def send_post_request(url: str, body: dict[str, int]) -> None:
    ...

내장 함수 isinstance()와 issubclass()는 두 번째 인자로 GenericAlias 형을 받아들이지 않습니다:

>>> isinstance([1, 2], list[str])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: isinstance() argument 2 cannot be a parameterized generic

The Python runtime does not enforce type annotations. This extends to generic types and their type parameters. When creating a container object from a GenericAlias, the elements in the container are not checked against their type. For example, the following code is discouraged, but will run without errors:

>>> t = list[str]
>>> t([1, 2, 3])
[1, 2, 3]

또한, 매개 변수화된 제네릭은 객체 생성 중에 형 매개 변수를 지웁니다:

>>> t = list[str]
>>> type(t)
<class 'types.GenericAlias'>

>>> l = t()
>>> type(l)
<class 'list'>

제네릭에서 repr()이나 str()을 호출하면 매개 변수화된 형이 표시됩니다:

>>> repr(list[int])
'list[int]'

>>> str(list[int])
'list[int]'

The __getitem__() method of generic containers will raise an exception to disallow mistakes like dict[str][str]:

>>> dict[str][str]
Traceback (most recent call last):
  ...
TypeError: dict[str] is not a generic class

However, such expressions are valid when type variables are used. The index must have as many elements as there are type variable items in the GenericAlias object’s __args__.

>>> from typing import TypeVar
>>> Y = TypeVar('Y')
>>> dict[str, Y][int]
dict[str, int]

Standard Generic Classes

The following standard library classes support parameterized generics. This list is non-exhaustive.

tuple

list

dict

set

frozenset

type

collections.deque

collections.defaultdict

collections.OrderedDict

collections.Counter

collections.ChainMap

collections.abc.Awaitable

collections.abc.Coroutine

collections.abc.AsyncIterable

collections.abc.AsyncIterator

collections.abc.AsyncGenerator

collections.abc.Iterable

collections.abc.Iterator

collections.abc.Generator

collections.abc.Reversible

collections.abc.Container

collections.abc.Collection

collections.abc.Callable

collections.abc.Set

collections.abc.MutableSet

collections.abc.Mapping

collections.abc.MutableMapping

collections.abc.Sequence

collections.abc.MutableSequence

collections.abc.MappingView

collections.abc.KeysView

collections.abc.ItemsView

collections.abc.ValuesView

contextlib.AbstractContextManager

contextlib.AbstractAsyncContextManager

dataclasses.Field

functools.cached_property

functools.partialmethod

os.PathLike

queue.LifoQueue

queue.Queue

queue.PriorityQueue

queue.SimpleQueue

re.Pattern

re.Match

shelve.BsdDbShelf

shelve.DbfilenameShelf

shelve.Shelf

types.MappingProxyType

weakref.WeakKeyDictionary

weakref.WeakMethod

weakref.WeakSet

weakref.WeakValueDictionary

Special Attributes of GenericAlias objects

모든 매개 변수화된 제네릭은 특수 읽기 전용 어트리뷰트를 구현합니다.

genericalias.__origin__

이 어트리뷰트는 매개 변수화되지 않은 제네릭 클래스를 가리킵니다:

>>> list[int].__origin__
<class 'list'>

genericalias.__args__

This attribute is a tuple (possibly of length 1) of generic types passed to the original __class_getitem__() of the generic class:

>>> dict[str, list[int]].__args__
(<class 'str'>, list[int])

genericalias.__parameters__

이 어트리뷰트는 __args__에서 발견된 고유한 형 변수의 게으르게(lazily) 계산된 튜플(비어있을 수 있습니다)입니다:

>>> from typing import TypeVar

>>> T = TypeVar('T')
>>> list[T].__parameters__
(~T,)

참고

A GenericAlias object with typing.ParamSpec parameters may not have correct __parameters__ after substitution because typing.ParamSpec is intended primarily for static type checking.

genericalias.__unpacked__

A boolean that is true if the alias has been unpacked using the * operator (see TypeVarTuple).

Added in version 3.11.

더 보기

PEP 484 [https://peps.python.org/pep-0484/] - Type Hints

Introducing Python’s framework for type annotations.

PEP 585 [https://peps.python.org/pep-0585/] - Type Hinting Generics In Standard Collections

Introducing the ability to natively parameterize standard-library classes, provided they implement the special class method __class_getitem__().

제네릭, user-defined generics and typing.Generic

Documentation on how to implement generic classes that can be parameterized at runtime and understood by static type-checkers.

Added in version 3.9.

Union Type

A union object holds the value of the | (bitwise or) operation on multiple type objects. These types are intended primarily for type annotations. The union type expression enables cleaner type hinting syntax compared to typing.Union.

X | Y | ...

Defines a union object which holds types X, Y, and so forth. X | Y means either X or Y. It is equivalent to typing.Union[X, Y]. For example, the following function expects an argument of type int or float:

def square(number: int | float) -> int | float:
    return number ** 2

참고

The | operand cannot be used at runtime to define unions where one or more members is a forward reference. For example, int | "Foo", where "Foo" is a reference to a class not yet defined, will fail at runtime. For unions which include forward references, present the whole expression as a string, e.g. "int | Foo".

union_object == other

Union objects can be tested for equality with other union objects. Details:

Unions of unions are flattened:

(int | str) | float == int | str | float

Redundant types are removed:

int | str | int == int | str

When comparing unions, the order is ignored:

int | str == str | int

It is compatible with typing.Union:

int | str == typing.Union[int, str]

Optional types can be spelled as a union with None:

str | None == typing.Optional[str]

isinstance(obj, union_object)

issubclass(obj, union_object)

Calls to isinstance() and issubclass() are also supported with a union object:

>>> isinstance("", int | str)
True

However, parameterized generics in union objects cannot be checked:

>>> isinstance(1, int | list[int])  # short-circuit evaluation
True
>>> isinstance([1], int | list[int])
Traceback (most recent call last):
  ...
TypeError: isinstance() argument 2 cannot be a parameterized generic

The user-exposed type for the union object can be accessed from types.UnionType and used for isinstance() checks. An object cannot be instantiated from the type:

>>> import types
>>> isinstance(int | str, types.UnionType)
True
>>> types.UnionType()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot create 'types.UnionType' instances

참고

The __or__() method for type objects was added to support the syntax X | Y. If a metaclass implements __or__(), the Union may override it:

>>> class M(type):
...     def __or__(self, other):
...         return "Hello"
...
>>> class C(metaclass=M):
...     pass
...
>>> C | int
'Hello'
>>> int | C
int | C

더 보기

PEP 604 [https://peps.python.org/pep-0604/] – PEP proposing the X | Y syntax and the Union type.

Added in version 3.10.

기타 내장형

인터프리터는 여러 가지 다른 객체를 지원합니다. 이것들 대부분은 한두 가지 연산만 지원합니다.

모듈

모듈에 대한 유일한 특별한 연산은 어트리뷰트 액세스입니다: m.name. 여기서 m 은 모듈이고 name 은 m 의 심볼 테이블에 정의된 이름에 액세스합니다. 모듈 어트리뷰트는 대입할 수 있습니다. (import 문은 엄밀히 말하면 모듈 객체에 대한 연산이 아닙니다; import foo 는 foo 라는 이름의 모듈 객체가 존재할 것을 요구하지 않고, 어딘가에 있는 foo 라는 이름의 (외부) 정의 를 요구합니다.

모든 모듈의 특수 어트리뷰트는 __dict__ 입니다. 이것은 모듈의 심볼 테이블을 저장하는 딕셔너리입니다. 이 딕셔너리를 수정하면 모듈의 심볼 테이블이 실제로 변경되지만, __dict__ 어트리뷰트에 대한 직접 대입은 불가능합니다 (m.__dict__['a'] = 1 라고 쓸 수 있고, m.a 가 1 이 되지만, m.__dict__ = {} 라고 쓸 수는 없습니다). __dict__ 의 직접적인 수정은 추천하지 않습니다.

인터프리터에 내장된 모듈은 다음과 같이 쓰입니다: <module 'sys' (built-in)>. 파일에서 로드되면, <module 'os' from '/usr/local/lib/pythonX.Y/os.pyc'> 처럼 쓰입니다.

클래스와 클래스 인스턴스

여기에 대해서는 객체, 값, 형와 클래스 정의를 참조하세요.

함수

함수 객체는 함수 정의로 만들어집니다. 함수 객체에 대한 유일한 연산은 호출하는 것입니다: func(argument-list).

함수 객체에는 내장 함수와 사용자 정의 함수라는 두 가지 종류가 있습니다. 두 함수 모두 같은 연산(함수 호출)을 지원하지만, 구현이 다르므로 서로 다른 객체 형입니다.

자세한 정보는 함수 정의을 보십시오.

메서드

Methods are functions that are called using the attribute notation. There are two flavors: built-in methods (such as append() on lists) and class instance method. Built-in methods are described with the types that support them.

If you access a method (a function defined in a class namespace) through an instance, you get a special object: a bound method (also called instance method) object. When called, it will add the self argument to the argument list. Bound methods have two special read-only attributes: m.__self__ is the object on which the method operates, and m.__func__ is the function implementing the method. Calling m(arg-1, arg-2, ..., arg-n) is completely equivalent to calling m.__func__(m.__self__, arg-1, arg-2, ..., arg-n).

Like function objects, bound method objects support getting arbitrary attributes. However, since method attributes are actually stored on the underlying function object (method.__func__), setting method attributes on bound methods is disallowed. Attempting to set an attribute on a method results in an AttributeError being raised. In order to set a method attribute, you need to explicitly set it on the underlying function object:

>>> class C:
...     def method(self):
...         pass
...
>>> c = C()
>>> c.method.whoami = 'my name is method'  # can't set on the method
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'method' object has no attribute 'whoami'
>>> c.method.__func__.whoami = 'my name is method'
>>> c.method.whoami
'my name is method'

See 인스턴스 메서드(Instance methods) for more information.

코드 객체

Code objects are used by the implementation to represent “pseudo-compiled” executable Python code such as a function body. They differ from function objects because they don’t contain a reference to their global execution environment. Code objects are returned by the built-in compile() function and can be extracted from function objects through their __code__ attribute. See also the code module.

Accessing __code__ raises an auditing event object.__getattr__ with arguments obj and "__code__".

코드 객체는 exec() 또는 eval() 내장 함수에 (소스 문자열 대신) 전달하여 실행하거나 값을 구할 수 있습니다.

자세한 정보는 표준형 계층를 보십시오.

형 객체

형 객체는 다양한 객체 형을 나타냅니다. 객체의 형은 내장 함수 type()으로 액세스할 수 있습니다. 형에는 특별한 연산이 없습니다. 표준 모듈 types 는 모든 표준 내장형의 이름을 정의합니다.

형은 다음과 같이 쓰입니다: <class 'int'>.

널 객체

이 객체는 명시적으로 값을 돌려주지 않는 함수에 의해 반환됩니다. 특별한 연산을 지원하지 않습니다. 정확하게 하나의 널 객체가 있으며, 이름은 None(내장 이름)입니다. type(None)() 은 같은 싱글톤을 만듭니다.

None 이라고 쓰입니다.

Ellipsis 객체

이 객체는 일반적으로 슬라이싱에 사용됩니다 (슬라이싱(Slicings) 를 참조하세요). 특별한 연산을 지원하지 않습니다. 정확하게 하나의 Ellipsis 객체가 있으며, 이름은 Ellipsis(내장 이름)입니다. type(Ellipsis)() 는 Ellipsis 싱글톤을 만듭니다.

Ellipsis 나 ... 로 쓰입니다.

NotImplemented 객체

This object is returned from comparisons and binary operations when they are asked to operate on types they don’t support. See 비교 for more information. There is exactly one NotImplemented object. type(NotImplemented)() produces the singleton instance.

It is written as NotImplemented.

내부 객체

See 표준형 계층 for this information. It describes stack frame objects, traceback objects, and slice objects.

특수 어트리뷰트

관련성이 있을 때, 구현은 몇 가지 객체 유형에 몇 가지 특수 읽기 전용 어트리뷰트를 추가합니다. 이 중 일부는 dir() 내장 함수에 의해 보고되지 않습니다.

definition.__name__

클래스, 함수, 메서드, 디스크립터 또는 제너레이터 인스턴스의 이름.

definition.__qualname__

클래스, 함수, 메서드, 디스크립터 또는 제너레이터 인스턴스의 정규화된 이름.

Added in version 3.3.

definition.__module__

The name of the module in which a class or function was defined.

definition.__doc__

The documentation string of a class or function, or None if undefined.

definition.__type_params__

The type parameters of generic classes, functions, and type aliases. For classes and functions that are not generic, this will be an empty tuple.

Added in version 3.12.

Integer string conversion length limitation

CPython has a global limit for converting between int and str to mitigate denial of service attacks. This limit only applies to decimal or other non-power-of-two number bases. Hexadecimal, octal, and binary conversions are unlimited. The limit can be configured.

The int type in CPython is an arbitrary length number stored in binary form (commonly known as a “bignum”). There exists no algorithm that can convert a string to a binary integer or a binary integer to a string in linear time, unless the base is a power of 2. Even the best known algorithms for base 10 have sub-quadratic complexity. Converting a large value such as int('1' * 500_000) can take over a second on a fast CPU.

Limiting conversion size offers a practical way to avoid CVE 2020-10735 [https://www.cve.org/CVERecord?id=CVE-2020-10735].

The limit is applied to the number of digit characters in the input or output string when a non-linear conversion algorithm would be involved. Underscores and the sign are not counted towards the limit.

When an operation would exceed the limit, a ValueError is raised:

>>> import sys
>>> sys.set_int_max_str_digits(4300)  # Illustrative, this is the default.
>>> _ = int('2' * 5432)
Traceback (most recent call last):
...
ValueError: Exceeds the limit (4300 digits) for integer string conversion: value has 5432 digits; use sys.set_int_max_str_digits() to increase the limit
>>> i = int('2' * 4300)
>>> len(str(i))
4300
>>> i_squared = i*i
>>> len(str(i_squared))
Traceback (most recent call last):
...
ValueError: Exceeds the limit (4300 digits) for integer string conversion; use sys.set_int_max_str_digits() to increase the limit
>>> len(hex(i_squared))
7144
>>> assert int(hex(i_squared), base=16) == i*i  # Hexadecimal is unlimited.

The default limit is 4300 digits as provided in sys.int_info.default_max_str_digits. The lowest limit that can be configured is 640 digits as provided in sys.int_info.str_digits_check_threshold.

Verification:

>>> import sys
>>> assert sys.int_info.default_max_str_digits == 4300, sys.int_info
>>> assert sys.int_info.str_digits_check_threshold == 640, sys.int_info
>>> msg = int('578966293710682886880994035146873798396722250538762761564'
...           '9252925514383915483333812743580549779436104706260696366600'
...           '571186405732').to_bytes(53, 'big')
...

Added in version 3.11.

Affected APIs

The limitation only applies to potentially slow conversions between int and str or bytes:

int(string) with default base 10.

int(string, base) for all bases that are not a power of 2.

str(integer).

repr(integer).

any other string conversion to base 10, for example f"{integer}", "{}".format(integer), or b"%d" % integer.

The limitations do not apply to functions with a linear algorithm:

int(string, base) with base 2, 4, 8, 16, or 32.

int.from_bytes() and int.to_bytes().

hex(), oct(), bin().

포맷 명세 미니 언어 for hex, octal, and binary numbers.

str to float.

str to decimal.Decimal.

Configuring the limit

Before Python starts up you can use an environment variable or an interpreter command line flag to configure the limit:

PYTHONINTMAXSTRDIGITS, e.g. PYTHONINTMAXSTRDIGITS=640 python3 to set the limit to 640 or PYTHONINTMAXSTRDIGITS=0 python3 to disable the limitation.

-X int_max_str_digits, e.g. python3 -X int_max_str_digits=640

sys.flags.int_max_str_digits contains the value of PYTHONINTMAXSTRDIGITS or -X int_max_str_digits. If both the env var and the -X option are set, the -X option takes precedence. A value of -1 indicates that both were unset, thus a value of sys.int_info.default_max_str_digits was used during initialization.

From code, you can inspect the current limit and set a new one using these sys APIs:

sys.get_int_max_str_digits() and sys.set_int_max_str_digits() are a getter and setter for the interpreter-wide limit. Subinterpreters have their own limit.

Information about the default and minimum can be found in sys.int_info:

sys.int_info.default_max_str_digits is the compiled-in default limit.

sys.int_info.str_digits_check_threshold is the lowest accepted value for the limit (other than 0 which disables it).

Added in version 3.11.

조심

Setting a low limit can lead to problems. While rare, code exists that contains integer constants in decimal in their source that exceed the minimum threshold. A consequence of setting the limit is that Python source code containing decimal integer literals longer than the limit will encounter an error during parsing, usually at startup time or import time or even at installation time - anytime an up to date .pyc does not already exist for the code. A workaround for source that contains such large constants is to convert them to 0x hexadecimal form as it has no limit.

Test your application thoroughly if you use a low limit. Ensure your tests run with the limit set early via the environment or flag so that it applies during startup and even during any installation step that may invoke Python to precompile .py sources to .pyc files.

Recommended configuration

The default sys.int_info.default_max_str_digits is expected to be reasonable for most applications. If your application requires a different limit, set it from your main entry point using Python version agnostic code as these APIs were added in security patch releases in versions before 3.12.

Example:

>>> import sys
>>> if hasattr(sys, "set_int_max_str_digits"):
...     upper_bound = 68000
...     lower_bound = 4004
...     current_limit = sys.get_int_max_str_digits()
...     if current_limit == 0 or current_limit > upper_bound:
...         sys.set_int_max_str_digits(upper_bound)
...     elif current_limit < lower_bound:
...         sys.set_int_max_str_digits(lower_bound)

If you need to disable it entirely, set it to 0.

각주

[1]

이 특수 메서드에 대한 추가 정보는 파이썬 레퍼런스 설명서(기본적인 커스터마이제이션)에서 찾을 수 있습니다.

[2]

결과적으로, 리스트 [1, 2] 는 [1.0, 2.0] 과 같다고 취급되고, 튜플도 마찬가지입니다.

[3]

파서가 피연산자 유형을 알 수 없으므로 그럴 수밖에 없습니다.

[4] (1,2,3,4)

케이스 문자는 일반 범주 속성이 “Lu” (Letter, 대문자), “Ll” (Letter, 소문자), “Lt” (Letter, 제목 문자) 중 한 가지인 경우입니다.

[5] (1,2)

그래서, 튜플만을 포매팅하려면 포맷할 튜플 하나만을 포함하는 1-튜플을 제공해야 합니다.

내장 예외

파이썬에서, 모든 예외는 BaseException 에서 파생된 클래스의 인스턴스여야 합니다. 특정 클래스를 언급하는 except 절을 갖는 try 문에서, 그 절은 그 클래스에서 파생된 모든 예외 클래스를 처리합니다 (하지만 그것 이 계승하는 예외 클래스는 처리하지 않습니다). 서브 클래싱을 통해 관련되지 않은 두 개의 예외 클래스는 같은 이름을 갖는다 할지라도 결코 등등하게 취급되지 않습니다.

The built-in exceptions listed in this chapter can be generated by the interpreter or built-in functions. Except where mentioned, they have an “associated value” indicating the detailed cause of the error. This may be a string or a tuple of several items of information (e.g., an error code and a string explaining the code). The associated value is usually passed as arguments to the exception class’s constructor.

사용자 코드는 내장 예외를 일으킬 수 있습니다. 이것은 예외 처리기를 검사하거나 인터프리터가 같은 예외를 발생시키는 상황과 “같은” 에러 조건을 보고하는 데 사용할 수 있습니다. 그러나 사용자 코드가 부적절한 에러를 발생시키는 것을 막을 방법이 없음을 유의하십시오.

내장 예외 클래스는 새 예외를 정의하기 위해 서브 클래싱 될 수 있습니다. BaseException 이 아니라 Exception 클래스 나 그 서브 클래스 중 하나에서 새로운 예외를 파생시킬 것을 권장합니다. 예외 정의에 대한 더 많은 정보는 파이썬 자습서의 사용자 정의 예외 에 있습니다.

Exception context

Three attributes on exception objects provide information about the context in which the exception was raised:

BaseException.__context__

BaseException.__cause__

BaseException.__suppress_context__

When raising a new exception while another exception is already being handled, the new exception’s __context__ attribute is automatically set to the handled exception. An exception may be handled when an except or finally clause, or a with statement, is used.

This implicit exception context can be supplemented with an explicit cause by using from with raise:

raise new_exc from original_exc

The expression following from must be an exception or None. It will be set as __cause__ on the raised exception. Setting __cause__ also implicitly sets the __suppress_context__ attribute to True, so that using raise new_exc from None effectively replaces the old exception with the new one for display purposes (e.g. converting KeyError to AttributeError), while leaving the old exception available in __context__ for introspection when debugging.

The default traceback display code shows these chained exceptions in addition to the traceback for the exception itself. An explicitly chained exception in __cause__ is always shown when present. An implicitly chained exception in __context__ is shown only if __cause__ is None and __suppress_context__ is false.

두 경우 모두, 예외 자신은 항상 연결된 예외 뒤에 표시되어서, 트레이스백의 마지막 줄은 항상 마지막에 발생한 예외를 보여줍니다.

Inheriting from built-in exceptions

User code can create subclasses that inherit from an exception type. It’s recommended to only subclass one exception type at a time to avoid any possible conflicts between how the bases handle the args attribute, as well as due to possible memory layout incompatibilities.

CPython 구현 상세: Most built-in exceptions are implemented in C for efficiency, see: Objects/exceptions.c [https://github.com/python/cpython/tree/main/Objects/exceptions.c]. Some have custom memory layouts which makes it impossible to create a subclass that inherits from multiple exception types. The memory layout of a type is an implementation detail and might change between Python versions, leading to new conflicts in the future. Therefore, it’s recommended to avoid subclassing multiple exception types altogether.

베이스 클래스

다음 예외는 주로 다른 예외의 베이스 클래스로 사용됩니다.

exception BaseException

모든 내장 예외의 베이스 클래스입니다. 사용자 정의 클래스에 의해 직접 상속되는 것이 아닙니다 (그런 목적으로는 Exception을 사용하세요). 이 클래스의 인스턴스에 대해 str() 이 호출되면, 인스턴스로 전달된 인자(들)의 표현을 돌려줍니다. 인자가 없는 경우는 빈 문자열을 돌려줍니다.

args

예외 생성자에 주어진 인자들의 튜플. 일부 내장 예외(예, OSError)는 특정 수의 인자를 기대하고 이 튜플의 요소에 특별한 의미를 할당하는 반면, 다른 것들은 보통 오류 메시지를 제공하는 단일 문자열로만 호출됩니다.

with_traceback(tb)

This method sets tb as the new traceback for the exception and returns the exception object. It was more commonly used before the exception chaining features of PEP 3134 [https://peps.python.org/pep-3134/] became available. The following example shows how we can convert an instance of SomeException into an instance of OtherException while preserving the traceback. Once raised, the current frame is pushed onto the traceback of the OtherException, as would have happened to the traceback of the original SomeException had we allowed it to propagate to the caller.

try:
    ...
except SomeException:
    tb = sys.exception().__traceback__
    raise OtherException(...).with_traceback(tb)

__traceback__

A writable field that holds the traceback object associated with this exception. See also: raise 문.

add_note(note)

Add the string note to the exception’s notes which appear in the standard traceback after the exception string. A TypeError is raised if note is not a string.

Added in version 3.11.

__notes__

A list of the notes of this exception, which were added with add_note(). This attribute is created when add_note() is called.

Added in version 3.11.

exception Exception

모든 시스템 종료 외의 내장 예외는 이 클래스 파생됩니다. 모든 사용자 정의 예외도 이 클래스에서 파생되어야 합니다.

exception ArithmeticError

다양한 산술 에러가 일으키는 내장 예외들의 베이스 클래스: OverflowError, ZeroDivisionError, FloatingPointError.

exception BufferError

버퍼 관련 연산을 수행할 수 없을 때 발생합니다.

exception LookupError

매핑 또는 시퀀스에 사용된 키 나 인덱스가 잘못되었을 때 발생하는 예외의 베이스 클래스: IndexError, KeyError. codecs.lookup() 은 이 예외를 직접 일으킬 수 있습니다.

구체적인 예외

다음 예외는 일반적으로 직접 일으키는데 사용하는 예외입니다.

exception AssertionError

assert 문이 실패할 때 발생합니다.

exception AttributeError

어트리뷰트 참조(어트리뷰트 참조를 보세요)나 대입이 실패할 때 발생합니다. (객체가 어트리뷰트 참조나 어트리뷰트 대입을 아예 지원하지 않으면 TypeError 가 발생합니다.)

The name and obj attributes can be set using keyword-only arguments to the constructor. When set they represent the name of the attribute that was attempted to be accessed and the object that was accessed for said attribute, respectively.

버전 3.10에서 변경: Added the name and obj attributes.

exception EOFError

input() 함수가 데이터를 읽지 못한 상태에서 EOF (end-of-file) 조건을 만날 때 발생합니다. (주의하세요: io.IOBase.read() 와 io.IOBase.readline() 메서드는 EOF를 만날 때 빈 문자열을 돌려줍니다.)

exception FloatingPointError

현재 사용되지 않습니다.

exception GeneratorExit

제너레이터 또는 코루틴 이 닫힐 때 발생합니다; generator.close() 와 coroutine.close() 를 보십시오. 기술적으로 에러가 아니므로 Exception 대신에 BaseException 을 직접 계승합니다.

exception ImportError

import 문이 모듈을 로드하는 데 문제가 있을 때 발생합니다. 또한 from ... import 에서 임포트 하려는 이름을 찾을 수 없을 때도 발생합니다.

The optional name and path keyword-only arguments set the corresponding attributes:

name

The name of the module that was attempted to be imported.

path

The path to any file which triggered the exception.

버전 3.3에서 변경: name과 path 어트리뷰트를 추가했습니다.

exception ModuleNotFoundError

ImportError 의 서브 클래스인데, 모듈을 찾을 수 없을 때 import 가 일으킵니다. sys.modules 에서 None 이 발견될 때도 발생합니다.

Added in version 3.6.

exception IndexError

시퀀스 인덱스가 범위를 벗어날 때 발생합니다. (슬라이스 인덱스는 허용된 범위 내에 들어가도록 자동으로 잘립니다; 인덱스가 정수가 아니면 TypeError 가 발생합니다.)

exception KeyError

매핑 (딕셔너리) 키가 기존 키 집합에서 발견되지 않을 때 발생합니다.

exception KeyboardInterrupt

사용자가 인터럽트 키(일반적으로 Control-C 또는 Delete)를 누를 때 발생합니다. 실행 중에 인터럽트 검사가 정기적으로 수행됩니다. Exception을 잡는 코드에 의해 우연히 잡혀서, 인터프리터가 종료하는 것을 막지 못하도록 BaseException 를 계승합니다.

참고

Catching a KeyboardInterrupt requires special consideration. Because it can be raised at unpredictable points, it may, in some circumstances, leave the running program in an inconsistent state. It is generally best to allow KeyboardInterrupt to end the program as quickly as possible or avoid raising it entirely. (See Note on Signal Handlers and Exceptions.)

exception MemoryError

작업에 메모리가 부족하지만, 상황이 여전히 (일부 객체를 삭제해서) 복구될 수 있는 경우 발생합니다. 연관된 값은 어떤 종류의 (내부) 연산이 메모리를 다 써 버렸는지를 나타내는 문자열입니다. 하부 메모리 관리 아키텍처(C의 malloc() 함수)때문에, 인터프리터가 항상 이 상황을 완벽하게 복구할 수 있는 것은 아닙니다; 그런데도 통제를 벗어난 프로그램이 원인인 경우를 위해, 스택 트레이스백을 인쇄할 수 있도록 예외를 일으킵니다.

exception NameError

지역 또는 전역 이름을 찾을 수 없을 때 발생합니다. 이는 정규화되지 않은 이름에만 적용됩니다. 연관된 값은 찾을 수 없는 이름을 포함하는 에러 메시지입니다.

The name attribute can be set using a keyword-only argument to the constructor. When set it represent the name of the variable that was attempted to be accessed.

버전 3.10에서 변경: Added the name attribute.

exception NotImplementedError

이 예외는 RuntimeError 에서 파생됩니다. 사용자 정의 베이스 클래스에서, 파생 클래스가 재정의하도록 요구하는 추상 메서드나, 클래스가 개발되는 도중에 실제 구현이 추가될 필요가 있음을 나타낼 때 이 예외를 발생시켜야 합니다.

참고

연산자 나 메서드가 아예 지원되지 않는다는 것을 나타내는 데 사용해서는 안 됩니다 – 그 경우는 연산자 / 메서드를 정의하지 않거나, 서브 클래스면 None 으로 설정하십시오.

참고

NotImplementedError and NotImplemented are not interchangeable, even though they have similar names and purposes. See NotImplemented for details on when to use it.

exception OSError([arg])

exception OSError(errno, strerror[, filename[, winerror[, filename2]]])

이 예외는 시스템 함수가 시스템 관련 에러를 돌려줄 때 발생하는데, “파일을 찾을 수 없습니다(file not found)” 나 “디스크가 꽉 찼습니다(disk full)” 와 같은 (잘못된 인자형이나 다른 부수적인 에러가 아닌) 입출력 실패를 포함합니다.

생성자의 두 번째 형식은 아래에 설명된 해당 어트리뷰트를 설정합니다. 어트리뷰트를 지정하지 않으면 기본적으로 None 이 됩니다. 이전 버전과의 호환성을 위해, 세 개의 인자가 전달되면, args 어트리뷰트는 처음 두 생성자 인자의 2-튜플만 포함합니다.

아래의 OS 예외 에서 설명하는 것처럼, 생성자는 종종 OSError 의 서브 클래스를 돌려줍니다. 구체적인 서브 클래스는 최종 errno 값에 따라 다릅니다. 이 동작은 OSError 를 직접 혹은 별칭을 통해 생성할 때만 일어나고, 서브 클래싱할 때는 상속되지 않습니다.

errno

C 변수 errno 로부터 온 숫자 에러 코드.

winerror

윈도우에서, 네이티브 윈도우 에러 코드를 제공합니다. errno 어트리뷰트는 이 네이티브 에러 코드를 POSIX 코드로 대략 변환한 것입니다.

윈도우에서, winerror 생성자 인자가 정수인 경우, errno 어트리뷰트는 윈도우 에러 코드에서 결정되며 errno 인자는 무시됩니다. 다른 플랫폼에서는 winerror 인자가 무시되고 winerror 어트리뷰트가 없습니다.

strerror

운영 체제에서 제공하는 해당 에러 메시지. POSIX에서는 C 함수 perror() 로, 윈도우에서는 FormatMessage() 로 포맷합니다.

filename

filename2

(open() 또는 os.unlink() 와 같은) 파일 시스템 경로와 관련된 예외의 경우, filename 은 함수에 전달 된 파일 이름입니다. (os.rename()처럼) 두 개의 파일 시스템 경로를 수반하는 함수의 경우, filename2 는 두 번째 파일 이름에 해당합니다.

버전 3.3에서 변경: EnvironmentError, IOError, WindowsError, socket.error, select.error, mmap.error 가 OSError 로 병합되었고, 생성자는 서브 클래스를 반환할 수 있습니다.

버전 3.4에서 변경: The filename attribute is now the original file name passed to the function, instead of the name encoded to or decoded from the filesystem encoding and error handler. Also, the filename2 constructor argument and attribute was added.

exception OverflowError

Raised when the result of an arithmetic operation is too large to be represented. This cannot occur for integers (which would rather raise MemoryError than give up). However, for historical reasons, OverflowError is sometimes raised for integers that are outside a required range. Because of the lack of standardization of floating-point exception handling in C, most floating-point operations are not checked.

exception PythonFinalizationError

This exception is derived from RuntimeError. It is raised when an operation is blocked during interpreter shutdown also known as Python finalization.

Examples of operations which can be blocked with a PythonFinalizationError during the Python finalization:

Creating a new Python thread.

os.fork().

See also the sys.is_finalizing() function.

Added in version 3.13: 이전에는 평범한 RuntimeError 가 발생했습니다.

exception RecursionError

이 예외는 RuntimeError 에서 파생됩니다. 인터프리터가 최대 재귀 깊이(sys.getrecursionlimit() 참조)가 초과하였음을 감지할 때 발생합니다.

Added in version 3.5: 이전에는 평범한 RuntimeError 가 발생했습니다.

exception ReferenceError

이 예외는 weakref.proxy() 함수가 만든 약한 참조 프락시가 이미 가비지 수집된 참조 대상의 어트리뷰트를 액세스하는 데 사용될 때 발생합니다. 약한 참조에 대한 더 자세한 정보는 weakref 모듈을 보십시오.

exception RuntimeError

다른 범주에 속하지 않는 에러가 감지될 때 발생합니다. 연관된 값은 정확히 무엇이 잘못되었는지를 나타내는 문자열입니다.

exception StopIteration

이터레이터에 의해 생성된 항목이 더 없다는 것을 알려주기 위해, 내장 함수 next()와 이터레이터의 __next__() 메서드가 일으킵니다.

value

The exception object has a single attribute value, which is given as an argument when constructing the exception, and defaults to None.

제너레이터 나 코루틴 함수가 복귀할 때, 새 StopIteration 인스턴스를 발생시키고, 함수가 돌려주는 값을 예외 생성자의 value 매개변수로 사용합니다.

제너레이터 코드가 직간접적으로 StopIteration 를 일으키면, RuntimeError 로 변환됩니다 (StopIteration 은 새 예외의 원인(__cause__)으로 남겨둡니다).

버전 3.3에서 변경: value 어트리뷰트와 제너레이터 함수가 이 값을 돌려주는 기능을 추가했습니다.

버전 3.5에서 변경: from __future__ import generator_stop 를 통한 RuntimeError 변환을 도입했습니다. PEP 479 [https://peps.python.org/pep-0479/]를 참조하세요.

버전 3.7에서 변경: 기본적으로 모든 코드에서 PEP 479 [https://peps.python.org/pep-0479/]를 활성화합니다: 제너레이터에서 발생한 StopIteration 에러는 RuntimeError 로 변환됩니다.

exception StopAsyncIteration

Must be raised by __anext__() method of an asynchronous iterator object to stop the iteration.

Added in version 3.5.

exception SyntaxError(message, details)

Raised when the parser encounters a syntax error. This may occur in an import statement, in a call to the built-in functions compile(), exec(), or eval(), or when reading the initial script or standard input (also interactively).

The str() of the exception instance returns only the error message. Details is a tuple whose members are also available as separate attributes.

filename

문법 오류가 발생한 파일의 이름.

lineno

오류가 발생한 파일의 줄 번호. 1-인덱싱됩니다: 파일의 첫 번째 줄은 lineno가 1입니다.

offset

오류가 발생한 줄의 열. 1-인덱싱됩니다: 줄의 첫 번째 문자는 offset이 1입니다.

text

오류를 수반한 소스 코드 텍스트.

end_lineno

Which line number in the file the error occurred ends in. This is 1-indexed: the first line in the file has a lineno of 1.

end_offset

The column in the end line where the error occurred finishes. This is 1-indexed: the first character in the line has an offset of 1.

For errors in f-string fields, the message is prefixed by “f-string: ” and the offsets are offsets in a text constructed from the replacement expression. For example, compiling f’Bad {a b} field’ results in this args attribute: (‘f-string: …’, (‘’, 1, 2, ‘(a b)n’, 1, 5)).

버전 3.10에서 변경: Added the end_lineno and end_offset attributes.

exception IndentationError

잘못된 들여쓰기와 관련된 문법 오류의 베이스 클래스입니다. SyntaxError 의 서브 클래스입니다.

exception TabError

들여쓰기가 일관성없는 탭과 스페이스 사용을 포함하는 경우 발생합니다. IndentationError 의 서브 클래스입니다.

exception SystemError

인터프리터가 내부 에러를 발견했지만, 모든 희망을 포기할 만큼 상황이 심각해 보이지는 않을 때 발생합니다. 연관된 값은 무엇이 잘못되었는지 (저수준의 용어로) 나타내는 문자열입니다.

이것을 파이썬 인터프리터의 저자 또는 관리자에게 알려야 합니다. 파이썬 인터프리터의 버전 (sys.version; 대화식 파이썬 세션의 시작 부분에도 출력됩니다), 정확한 에러 메시지 (예외의 연관된 값) 그리고 가능하다면 에러를 일으킨 프로그램의 소스를 제공해 주십시오.

exception SystemExit

이 예외는 sys.exit() 함수가 일으킵니다. Exception을 잡는 코드에 의해 우연히 잡히지 않도록, Exception 대신에 BaseException 을 상속합니다. 이렇게 하면 예외가 올바르게 전파되어 인터프리터가 종료됩니다. 처리되지 않으면, 파이썬 인터프리터가 종료됩니다; 스택 트레이스백은 인쇄되지 않습니다. 생성자는 sys.exit() 에 전달된 것과 같은 선택적 인자를 받아들입니다. 값이 정수이면 시스템 종료 상태를 지정합니다 (C의 exit() 함수에 전달됩니다); None 이면 종료 상태는 0입니다; 다른 형(가령 문자열)이면 객체의 값이 인쇄되고 종료 상태는 1입니다.

sys.exit() 에 대한 호출은 예외로 변환되어 뒷정리 처리기 (try 문의 finally 절) 가 실행될 수 있도록 합니다. 그래서 디버거는 제어권을 잃을 위험 없이 스크립트를 실행할 수 있습니다. 즉시 종료가 절대적으로 필요한 경우에는 os._exit() 함수를 사용할 수 있습니다 (예를 들어, os.fork() 호출 후의 자식 프로세스에서).

code

생성자에 전달되는 종료 상태 또는 에러 메시지입니다. (기본값은 None 입니다.)

exception TypeError

연산이나 함수가 부적절한 형의 객체에 적용될 때 발생합니다. 연관된 값은 형 불일치에 대한 세부 정보를 제공하는 문자열입니다.

이 예외는 객체에 시도된 연산이 지원되지 않으며 그럴 의도도 없음을 나타내기 위해 사용자 코드가 발생시킬 수 있습니다. 만약 객체가 주어진 연산을 지원할 의사는 있지만, 아직 구현을 제공하지 않는 경우라면, NotImplementedError 를 발생시키는 것이 적합합니다.

잘못된 형의 인자를 전달하면 (가령 int 를 기대하는데 list를 전달하기), TypeError 를 일으켜야 합니다. 하지만 잘못된 값을 갖는 인자를 전달하면 (가령 범위를 넘어서는 숫자) ValueError 를 일으켜야 합니다.

exception UnboundLocalError

함수 나 메서드에서 지역 변수를 참조하지만, 해당 변수에 값이 연결되지 않으면 발생합니다. 이것은 NameError 의 서브 클래스입니다.

exception UnicodeError

유니코드 관련 인코딩 또는 디코딩 에러가 일어날 때 발생합니다. ValueError 의 서브 클래스입니다.

UnicodeError 는 인코딩이나 디코딩 에러를 설명하는 어트리뷰트를 가지고 있습니다. 예를 들어, err.object[err.start:err.end] 는 코덱이 실패한 잘못된 입력을 제공합니다.

encoding

에러를 발생시킨 인코딩의 이름입니다.

reason

구체적인 코덱 오류를 설명하는 문자열입니다.

object

코덱이 인코딩 또는 디코딩하려고 시도한 객체입니다.

start

object 에 있는 잘못된 데이터의 최초 인덱스입니다.

end

object 에 있는 마지막으로 잘못된 데이터의 바로 다음 인덱스입니다.

exception UnicodeEncodeError

인코딩 중에 유니코드 관련 에러가 일어나면 발생합니다. UnicodeError 의 서브 클래스입니다.

exception UnicodeDecodeError

디코딩 중에 유니코드 관련 에러가 일어나면 발생합니다. UnicodeError 의 서브 클래스입니다.

exception UnicodeTranslateError

번역 중에 유니코드 관련 에러가 일어나면 발생합니다. UnicodeError 의 서브 클래스입니다.

exception ValueError

연산이나 함수가 올바른 형이지만 부적절한 값을 가진 인자를 받았고, 상황이 IndexError 처럼 더 구체적인 예외로 설명되지 않는 경우 발생합니다.

exception ZeroDivisionError

나누기 또는 모듈로 연산의 두 번째 인자가 0일 때 발생합니다. 연관된 값은 피연산자의 형과 연산을 나타내는 문자열입니다.

다음 예외는 이전 버전과의 호환성을 위해 유지됩니다; 파이썬 3.3부터는 OSError 의 별칭입니다.

exception EnvironmentError

exception IOError

exception WindowsError

윈도우에서만 사용할 수 있습니다.

OS 예외

다음의 예외는 OSError 의 서브 클래스이며, 시스템 에러 코드에 따라 발생합니다.

exception BlockingIOError

Raised when an operation would block on an object (e.g. socket) set for non-blocking operation. Corresponds to errno EAGAIN, EALREADY, EWOULDBLOCK and EINPROGRESS.

OSError 의 것 외에도, BlockingIOError 는 어트리뷰트를 하나 더 가질 수 있습니다:

characters_written

블록 되기 전에 스트림에 쓴 문자 수를 포함하는 정수. 이 어트리뷰트는 io 모듈에서 버퍼링 된 입출력 클래스를 사용할 때 쓸 수 있습니다.

exception ChildProcessError

Raised when an operation on a child process failed. Corresponds to errno ECHILD.

exception ConnectionError

연결 관련 문제에 대한 베이스 클래스입니다.

서브 클래스는 BrokenPipeError, ConnectionAbortedError, ConnectionRefusedError 및 ConnectionResetError 입니다.

exception BrokenPipeError

A subclass of ConnectionError, raised when trying to write on a pipe while the other end has been closed, or trying to write on a socket which has been shutdown for writing. Corresponds to errno EPIPE and ESHUTDOWN.

exception ConnectionAbortedError

A subclass of ConnectionError, raised when a connection attempt is aborted by the peer. Corresponds to errno ECONNABORTED.

exception ConnectionRefusedError

A subclass of ConnectionError, raised when a connection attempt is refused by the peer. Corresponds to errno ECONNREFUSED.

exception ConnectionResetError

A subclass of ConnectionError, raised when a connection is reset by the peer. Corresponds to errno ECONNRESET.

exception FileExistsError

Raised when trying to create a file or directory which already exists. Corresponds to errno EEXIST.

exception FileNotFoundError

Raised when a file or directory is requested but doesn’t exist. Corresponds to errno ENOENT.

exception InterruptedError

Raised when a system call is interrupted by an incoming signal. Corresponds to errno EINTR.

버전 3.5에서 변경: 이제 파이썬은 시스템 호출이 시그널에 의해 중단될 때, 시그널 처리기가 예외를 일으키는 경우를 제외하고 (이유는 PEP 475 [https://peps.python.org/pep-0475/] 를 참조하세요), InterruptedError 를 일으키는 대신 시스템 호출을 재시도합니다.

exception IsADirectoryError

Raised when a file operation (such as os.remove()) is requested on a directory. Corresponds to errno EISDIR.

exception NotADirectoryError

Raised when a directory operation (such as os.listdir()) is requested on something which is not a directory. On most POSIX platforms, it may also be raised if an operation attempts to open or traverse a non-directory file as if it were a directory. Corresponds to errno ENOTDIR.

exception PermissionError

Raised when trying to run an operation without the adequate access rights - for example filesystem permissions. Corresponds to errno EACCES, EPERM, and ENOTCAPABLE.

버전 3.11.1에서 변경: WASI’s ENOTCAPABLE is now mapped to PermissionError.

exception ProcessLookupError

Raised when a given process doesn’t exist. Corresponds to errno ESRCH.

exception TimeoutError

Raised when a system function timed out at the system level. Corresponds to errno ETIMEDOUT.

Added in version 3.3: 위의 모든 OSError 서브 클래스가 추가되었습니다.

더 보기

PEP 3151 [https://peps.python.org/pep-3151/] - OS 및 IO 예외 계층 구조 재작업

경고

다음 예외는 경고 범주로 사용됩니다; 자세한 정보는 경고 범주 설명서를 보십시오.

exception Warning

경고 범주의 베이스 클래스입니다.

exception UserWarning

사용자 코드에 의해 만들어지는 경고의 베이스 클래스입니다.

exception DeprecationWarning

폐지된 기능에 대한 경고의 베이스 클래스인데, 그 경고가 다른 파이썬 개발자를 대상으로 하는 경우입니다.

__main__ 모듈을 제외하고, 기본 경고 필터에 의해 무시됩니다 (PEP 565 [https://peps.python.org/pep-0565/]). 파이썬 개발 모드를 활성화하면 이 경고가 표시됩니다.

The deprecation policy is described in PEP 387 [https://peps.python.org/pep-0387/].

exception PendingDeprecationWarning

더는 사용되지 않고 장래에 폐지될 예정이지만, 지금 당장 폐지되지는 않은 기능에 관한 경고의 베이스 클래스입니다.

앞으로 있을 수도 있는 폐지에 관한 경고는 일반적이지 않기 때문에, 이 클래스는 거의 사용되지 않습니다. 이미 활성화된 폐지에는 DeprecationWarning을 선호합니다.

기본 경고 필터에 의해 무시됩니다. 파이썬 개발 모드를 활성화하면 이 경고가 표시됩니다.

The deprecation policy is described in PEP 387 [https://peps.python.org/pep-0387/].

exception SyntaxWarning

모호한 문법에 대한 경고의 베이스 클래스입니다.

exception RuntimeWarning

모호한 실행 시간 동작에 대한 경고의 베이스 클래스입니다.

exception FutureWarning

폐지된 기능에 대한 경고의 베이스 클래스인데, 그 경고가 파이썬으로 작성된 응용 프로그램의 최종 사용자를 대상으로 하는 경우입니다.

exception ImportWarning

모듈 임포트에 있을 수 있는 실수에 대한 경고의 베이스 클래스입니다.

기본 경고 필터에 의해 무시됩니다. 파이썬 개발 모드를 활성화하면 이 경고가 표시됩니다.

exception UnicodeWarning

유니코드와 관련된 경고의 베이스 클래스입니다.

exception EncodingWarning

Base class for warnings related to encodings.

See Opt-in EncodingWarning for details.

Added in version 3.10.

exception BytesWarning

bytes 및 bytearray 와 관련된 경고의 베이스 클래스입니다.

exception ResourceWarning

자원 사용과 관련된 경고의 베이스 클래스입니다.

기본 경고 필터에 의해 무시됩니다. 파이썬 개발 모드를 활성화하면 이 경고가 표시됩니다.

Added in version 3.2.

Exception groups

The following are used when it is necessary to raise multiple unrelated exceptions. They are part of the exception hierarchy so they can be handled with except like all other exceptions. In addition, they are recognised by except*, which matches their subgroups based on the types of the contained exceptions.

exception ExceptionGroup(msg, excs)

exception BaseExceptionGroup(msg, excs)

Both of these exception types wrap the exceptions in the sequence excs. The msg parameter must be a string. The difference between the two classes is that BaseExceptionGroup extends BaseException and it can wrap any exception, while ExceptionGroup extends Exception and it can only wrap subclasses of Exception. This design is so that except Exception catches an ExceptionGroup but not BaseExceptionGroup.

The BaseExceptionGroup constructor returns an ExceptionGroup rather than a BaseExceptionGroup if all contained exceptions are Exception instances, so it can be used to make the selection automatic. The ExceptionGroup constructor, on the other hand, raises a TypeError if any contained exception is not an Exception subclass.

message

The msg argument to the constructor. This is a read-only attribute.

exceptions

A tuple of the exceptions in the excs sequence given to the constructor. This is a read-only attribute.

subgroup(condition)

Returns an exception group that contains only the exceptions from the current group that match condition, or None if the result is empty.

The condition can be an exception type or tuple of exception types, in which case each exception is checked for a match using the same check that is used in an except clause. The condition can also be a callable (other than a type object) that accepts an exception as its single argument and returns true for the exceptions that should be in the subgroup.

The nesting structure of the current exception is preserved in the result, as are the values of its message, __traceback__, __cause__, __context__ and __notes__ fields. Empty nested groups are omitted from the result.

The condition is checked for all exceptions in the nested exception group, including the top-level and any nested exception groups. If the condition is true for such an exception group, it is included in the result in full.

Added in version 3.13: condition can be any callable which is not a type object.

split(condition)

Like subgroup(), but returns the pair (match, rest) where match is subgroup(condition) and rest is the remaining non-matching part.

derive(excs)

Returns an exception group with the same message, but which wraps the exceptions in excs.

This method is used by subgroup() and split(), which are used in various contexts to break up an exception group. A subclass needs to override it in order to make subgroup() and split() return instances of the subclass rather than ExceptionGroup.

subgroup() and split() copy the __traceback__, __cause__, __context__ and __notes__ fields from the original exception group to the one returned by derive(), so these fields do not need to be updated by derive().

>>> class MyGroup(ExceptionGroup):
...     def derive(self, excs):
...         return MyGroup(self.message, excs)
...
>>> e = MyGroup("eg", [ValueError(1), TypeError(2)])
>>> e.add_note("a note")
>>> e.__context__ = Exception("context")
>>> e.__cause__ = Exception("cause")
>>> try:
...    raise e
... except Exception as e:
...    exc = e
...
>>> match, rest = exc.split(ValueError)
>>> exc, exc.__context__, exc.__cause__, exc.__notes__
(MyGroup('eg', [ValueError(1), TypeError(2)]), Exception('context'), Exception('cause'), ['a note'])
>>> match, match.__context__, match.__cause__, match.__notes__
(MyGroup('eg', [ValueError(1)]), Exception('context'), Exception('cause'), ['a note'])
>>> rest, rest.__context__, rest.__cause__, rest.__notes__
(MyGroup('eg', [TypeError(2)]), Exception('context'), Exception('cause'), ['a note'])
>>> exc.__traceback__ is match.__traceback__ is rest.__traceback__
True

Note that BaseExceptionGroup defines __new__(), so subclasses that need a different constructor signature need to override that rather than __init__(). For example, the following defines an exception group subclass which accepts an exit_code and and constructs the group’s message from it.

class Errors(ExceptionGroup):
   def __new__(cls, errors, exit_code):
      self = super().__new__(Errors, f"exit code: {exit_code}", errors)
      self.exit_code = exit_code
      return self

   def derive(self, excs):
      return Errors(excs, self.exit_code)

Like ExceptionGroup, any subclass of BaseExceptionGroup which is also a subclass of Exception can only wrap instances of Exception.

Added in version 3.11.

예외 계층 구조

내장 예외의 클래스 계층 구조는 다음과 같습니다:

BaseException
 ├── BaseExceptionGroup
 ├── GeneratorExit
 ├── KeyboardInterrupt
 ├── SystemExit
 └── Exception
      ├── ArithmeticError
      │    ├── FloatingPointError
      │    ├── OverflowError
      │    └── ZeroDivisionError
      ├── AssertionError
      ├── AttributeError
      ├── BufferError
      ├── EOFError
      ├── ExceptionGroup [BaseExceptionGroup]
      ├── ImportError
      │    └── ModuleNotFoundError
      ├── LookupError
      │    ├── IndexError
      │    └── KeyError
      ├── MemoryError
      ├── NameError
      │    └── UnboundLocalError
      ├── OSError
      │    ├── BlockingIOError
      │    ├── ChildProcessError
      │    ├── ConnectionError
      │    │    ├── BrokenPipeError
      │    │    ├── ConnectionAbortedError
      │    │    ├── ConnectionRefusedError
      │    │    └── ConnectionResetError
      │    ├── FileExistsError
      │    ├── FileNotFoundError
      │    ├── InterruptedError
      │    ├── IsADirectoryError
      │    ├── NotADirectoryError
      │    ├── PermissionError
      │    ├── ProcessLookupError
      │    └── TimeoutError
      ├── ReferenceError
      ├── RuntimeError
      │    ├── NotImplementedError
      │    ├── PythonFinalizationError
      │    └── RecursionError
      ├── StopAsyncIteration
      ├── StopIteration
      ├── SyntaxError
      │    └── IndentationError
      │         └── TabError
      ├── SystemError
      ├── TypeError
      ├── ValueError
      │    └── UnicodeError
      │         ├── UnicodeDecodeError
      │         ├── UnicodeEncodeError
      │         └── UnicodeTranslateError
      └── Warning
           ├── BytesWarning
           ├── DeprecationWarning
           ├── EncodingWarning
           ├── FutureWarning
           ├── ImportWarning
           ├── PendingDeprecationWarning
           ├── ResourceWarning
           ├── RuntimeWarning
           ├── SyntaxWarning
           ├── UnicodeWarning
           └── UserWarning

텍스트 처리 서비스

이 장에서 설명하는 모듈은 광범위한 문자열 조작 연산과 기타 텍스트 처리 서비스를 제공합니다.

바이너리 데이터 서비스 에 기술되어 있는 codecs 모듈 또한 텍스트 처리와 밀접한 관련이 있습니다. 또한, 텍스트 시퀀스 형 — str 에 있는 파이썬의 내장 문자열형에 대한 설명서를 참조하십시오.

string — Common string operations

문자열 상수

ascii_letters

ascii_lowercase

ascii_uppercase

digits

hexdigits

octdigits

punctuation

printable

whitespace

사용자 지정 문자열 포매팅

Formatter

format()

vformat()

parse()

get_field()

get_value()

check_unused_args()

format_field()

convert_field()

포맷 문자열 문법

포맷 명세 미니 언어

포맷 예제

템플릿 문자열

Template

substitute()

safe_substitute()

is_valid()

get_identifiers()

template

도움 함수

capwords()

re — Regular expression operations

정규식 문법

모듈 내용

Flags

RegexFlag

A

ASCII

DEBUG

I

IGNORECASE

L

LOCALE

M

MULTILINE

NOFLAG

S

DOTALL

U

UNICODE

X

VERBOSE

Functions

compile()

search()

match()

fullmatch()

split()

findall()

finditer()

sub()

subn()

escape()

purge()

Exceptions

PatternError

msg

pattern

pos

lineno

colno

정규식 객체

Pattern

search()

match()

fullmatch()

split()

findall()

finditer()

sub()

subn()

flags

groups

groupindex

pattern

일치 객체

Match

expand()

group()

__getitem__()

groups()

groupdict()

start()

end()

span()

pos

endpos

lastindex

lastgroup

re

string

정규식 예제

쌍 검사하기

scanf() 시뮬레이션

search() 대 match()

전화번호부 만들기

텍스트 뒤섞기

모든 부사 찾기

모든 부사와 그 위치 찾기

날 문자열 표기법

토크나이저 작성하기

difflib — Helpers for computing deltas

Differ

HtmlDiff

__init__()

make_file()

make_table()

context_diff()

get_close_matches()

ndiff()

restore()

unified_diff()

diff_bytes()

IS_LINE_JUNK()

IS_CHARACTER_JUNK()

SequenceMatcher 객체

SequenceMatcher

set_seqs()

set_seq1()

set_seq2()

find_longest_match()

get_matching_blocks()

get_opcodes()

get_grouped_opcodes()

ratio()

quick_ratio()

real_quick_ratio()

SequenceMatcher 예제

Differ 객체

compare()

Differ 예제

difflib의 명령 줄 인터페이스

ndiff example

textwrap — Text wrapping and filling

wrap()

fill()

shorten()

dedent()

indent()

TextWrapper

width

expand_tabs

tabsize

replace_whitespace

drop_whitespace

initial_indent

subsequent_indent

fix_sentence_endings

break_long_words

break_on_hyphens

max_lines

placeholder

wrap()

fill()

unicodedata — Unicode Database

lookup()

name()

decimal()

digit()

numeric()

category()

bidirectional()

combining()

east_asian_width()

mirrored()

decomposition()

normalize()

is_normalized()

unidata_version

ucd_3_2_0

stringprep — Internet String Preparation

in_table_a1()

in_table_b1()

map_table_b2()

map_table_b3()

in_table_c11()

in_table_c12()

in_table_c11_c12()

in_table_c21()

in_table_c22()

in_table_c21_c22()

in_table_c3()

in_table_c4()

in_table_c5()

in_table_c6()

in_table_c7()

in_table_c8()

in_table_c9()

in_table_d1()

in_table_d2()

readline — GNU readline interface

backend

초기화 파일

parse_and_bind()

read_init_file()

줄 버퍼

get_line_buffer()

insert_text()

redisplay()

히스토리 파일

read_history_file()

write_history_file()

append_history_file()

get_history_length()

set_history_length()

히스토리 목록

clear_history()

get_current_history_length()

get_history_item()

remove_history_item()

replace_history_item()

add_history()

set_auto_history()

시동 훅

set_startup_hook()

set_pre_input_hook()

완성

set_completer()

get_completer()

get_completion_type()

get_begidx()

get_endidx()

set_completer_delims()

get_completer_delims()

set_completion_display_matches_hook()

예제

rlcompleter — Completion function for GNU readline

Completer

complete()

string — Common string operations

소스 코드: Lib/string.py [https://github.com/python/cpython/tree/main/Lib/string.py]

더 보기

텍스트 시퀀스 형 — str

문자열 메서드

문자열 상수

이 모듈에 정의된 상수는 다음과 같습니다:

string.ascii_letters

아래에 나오는 ascii_lowercase와 ascii_uppercase 상수를 이어붙인 것입니다. 이 값은 로케일에 의존적이지 않습니다.

string.ascii_lowercase

소문자 'abcdefghijklmnopqrstuvwxyz'. 이 값은 로케일에 의존적이지 않고 변경되지 않습니다.

string.ascii_uppercase

대문자 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'. 이 값은 로케일에 의존적이지 않고 변경되지 않습니다.

string.digits

문자열 '0123456789'.

string.hexdigits

문자열 '0123456789abcdefABCDEF'.

string.octdigits

문자열 '01234567'.

string.punctuation

C 로케일에서 구두점 문자로 간주하는 ASCII 문자의 문자열: !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~.

string.printable

인쇄 가능한 것으로 간주하는 ASCII 문자의 문자열. digits, ascii_letters, punctuation, whitespace 의 조합입니다.

string.whitespace

공백으로 간주하는 모든 ASCII 문자를 포함하는 문자열. 여기에는 스페이스, 탭, 줄 바꿈, 캐리지 리턴, 세로 탭 및 폼 피드 문자가 포함됩니다.

사용자 지정 문자열 포매팅

내장 문자열 클래스는 PEP 3101 [https://peps.python.org/pep-3101/] 에 설명된 format() 메서드를 통해 복잡한 변수 치환 및 값 포매팅을 수행할 수 있는 기능을 제공합니다. string 모듈의 Formatter 클래스는 내장 format() 메서드와 같은 구현을 사용하여 자신만의 문자열 포매팅 동작을 만들고 사용자 정의할 수 있게 합니다.

class string.Formatter

Formatter 클래스에는 다음과 같은 공개 메서드가 있습니다:

format(format_string, /, *args, **kwargs)

기본 API 메서드입니다. 포맷 문자열과 임의의 위치 및 키워드 인자의 집합을 받아들입니다. 이것은 vformat() 을 호출하는 래퍼일 뿐입니다.

버전 3.7에서 변경: 포맷 문자열 인자는 이제 위치 전용입니다.

vformat(format_string, args, kwargs)

이 함수는 실제 포맷 작업을 수행합니다. *args 와 **kwargs 문법을 사용하여 딕셔너리를 개별적인 인자로 언 패킹한 후 다시 패킹하는 대신 미리 정의된 인자 딕셔너리를 전달하고자 하는 경우를 위해 별도의 함수로 노출합니다. vformat() 은 포맷 문자열을 문자 데이터와 치환 필드로 분리하는 작업을 수행합니다. 아래에 설명된 다양한 메서드를 호출합니다.

이에 더해, Formatter 는 서브 클래스에 의해 대체될 목적으로 많은 메서드를 정의합니다:

parse(format_string)

format_string을 루핑하면서 튜플 (literal_text, field_name, format_spec, conversion) 의 이터러블을 반환합니다. 이것은 vformat() 이 문자열을 리터럴 텍스트와 치환 필드로 나누는 데 사용합니다.

튜플의 값은 개념적으로 리터럴 텍스트와 그 뒤를 따르는 하나의 치환 필드의 범위를 나타냅니다. 리터럴 텍스트가 없는 경우 (두 개의 치환 필드가 연속적으로 나타나는 경우 발생할 수 있습니다), literal_text 는 길이가 0인 문자열입니다. 치환 필드가 없는 경우 field_name, format_spec 및 conversion 값은 None 입니다.

get_field(field_name, args, kwargs)

parse() 가 반환한 field_name 을 (위를 보세요) 포맷될 객체로 변환합니다. 튜플 (obj, used_key) 를 반환합니다. 기본 버전은 “0[name]” 이나 “label.title”과 같이 PEP 3101 [https://peps.python.org/pep-3101/] 에 정의된 형식의 문자열을 받아들입니다. args 와 kwargs 는 vformat() 에 전달된 것과 같습니다. 반환 값 used_key 는 get_value() 의 key 매개 변수와 같은 의미가 있습니다.

get_value(key, args, kwargs)

지정된 필드의 값을 가져옵니다. key 인자는 정수 또는 문자열입니다. 정수의 경우, args 에 있는 위치 인자의 인덱스를 나타냅니다; 문자열인 경우, kwargs 에 있는 이름있는 인자를 나타냅니다.

args 매개 변수는 vformat() 의 위치 인자 목록으로 설정되고, kwargs 매개 변수는 키워드 인자 딕셔너리로 설정됩니다.

복합 필드 이름의 경우, 이러한 함수는 필드 이름의 첫 번째 구성 요소에 대해서만 호출됩니다; 후속 구성 요소는 일반 어트리뷰트 및 인덱싱 연산을 통해 처리됩니다.

그래서 예를 들어, 필드 표현식 ‘0.name’ 은 get_value() 가 key 인자 0으로 호출되도록 합니다. name 어트리뷰트는 get_value() 가 반환한 후에 내장 getattr() 함수를 호출하여 조회합니다.

인덱스 또는 키워드가 존재하지 않는 항목을 참조하면, IndexError 나 KeyError 가 발생합니다.

check_unused_args(used_args, args, kwargs)

원하는 경우 사용하지 않는 인자를 검사하도록 구현합니다. 이 함수에 대한 인자는 포맷 문자열에서 참조되는 모든 인자 키의 집합과 (위치 인자의 경우 정수, 이름있는 인자의 경우 문자열), vformat 으로 전달된 args 와 kwargs 에 대한 참조입니다. 사용되지 않은 인자의 집합은 이 매개 변수들로 계산할 수 있습니다. check_unused_args() 는 검사가 실패할 경우 예외를 발생시킬 것으로 가정합니다.

format_field(value, format_spec)

format_field() 는 단순히 전역 format() 내장 함수를 호출합니다. 서브 클래스가 재정의할 수 있도록 메서드가 제공됩니다.

convert_field(value, conversion)

(get_field() 가 반환한) 값(value)을 (parse() 메서드가 반환하는 튜플에 있는 것과 같은) 주어진 변환 유형(conversion)으로 변환합니다. 기본 버전은 ‘s’ (str), ‘r’ (repr) 및 ‘a’ (ascii) 변환 유형을 인식합니다.

포맷 문자열 문법

str.format() 메서드와 Formatter 클래스는 포맷 문자열에 대해서 같은 문법을 공유합니다 (Formatter 의 경우, 서브 클래스는 그들 자신의 포맷 문자열 문법을 정의 할 수 있습니다). 문법은 포맷 문자열 리터럴 과 관련 있지만, 덜 정교하며, 특히 임의의 표현식을 지원하지 않습니다.

포맷 문자열에는 중괄호 {} 로 둘러싸인 “치환 필드” 가 들어 있습니다. 중괄호 안에 포함되지 않은 것은 리터럴 텍스트로 간주하며 변경되지 않고 그대로 출력으로 복사됩니다. 리터럴 텍스트에 중괄호를 포함해야 하는 경우, 중복으로 이스케이프 할 수 있습니다: {{ 와 }}.

치환 필드의 문법은 다음과 같습니다:

replacement_field ::=  "{" [field_name] ["!" conversion] [":" format_spec] "}"
field_name        ::=  arg_name ("." attribute_name | "[" element_index "]")*
arg_name          ::=  [identifier | digit+]
attribute_name    ::=  identifier
element_index     ::=  digit+ | index_string
index_string      ::=  <any source character except "]"> +
conversion        ::=  "r" | "s" | "a"
format_spec       ::=  format-spec:format_spec

덜 형식적인 용어로, 치환 필드는 field_name 으로 시작할 수 있는데, 값이 포맷되어 출력에 치환 필드 대신 삽입될 객체를 지정합니다. field_name 다음에는 선택적으로 느낌표 '!' 가 앞에 오는 conversion 필드와 콜론 ':' 이 앞에 오는 format_spec 이 옵니다. 이 값은 치환 값에 대해 기본값이 아닌 포맷을 지정합니다.

포맷 명세 미니 언어 섹션을 참고하십시오.

The field_name itself begins with an arg_name that is either a number or a keyword. If it’s a number, it refers to a positional argument, and if it’s a keyword, it refers to a named keyword argument. An arg_name is treated as a number if a call to str.isdecimal() on the string would return true. If the numerical arg_names in a format string are 0, 1, 2, … in sequence, they can all be omitted (not just some) and the numbers 0, 1, 2, … will be automatically inserted in that order. Because arg_name is not quote-delimited, it is not possible to specify arbitrary dictionary keys (e.g., the strings '10' or ':-]') within a format string. The arg_name can be followed by any number of index or attribute expressions. An expression of the form '.name' selects the named attribute using getattr(), while an expression of the form '[index]' does an index lookup using __getitem__().

버전 3.1에서 변경: 위치 인자 지정자는 str.format() 에서 생략 할 수 있습니다. 그래서, '{} {}'.format(a, b) 는 '{0} {1}'.format(a, b) 과 동등합니다.

버전 3.4에서 변경: 위치 인자 지정자는 Formatter에서 생략 할 수 있습니다.

몇 가지 간단한 포맷 문자열 예제:

"First, thou shalt count to {0}"  # References first positional argument
"Bring me a {}"                   # Implicitly references the first positional argument
"From {} to {}"                   # Same as "From {0} to {1}"
"My quest is {name}"              # References keyword argument 'name'
"Weight in tons {0.weight}"       # 'weight' attribute of first positional arg
"Units destroyed: {players[0]}"   # First element of keyword argument 'players'.

The conversion field causes a type coercion before formatting. Normally, the job of formatting a value is done by the __format__() method of the value itself. However, in some cases it is desirable to force a type to be formatted as a string, overriding its own definition of formatting. By converting the value to a string before calling __format__(), the normal formatting logic is bypassed.

현재 세 가지 변환 플래그가 지원됩니다: '!s' 는 값에 str() 을 호출하고, '!r' 은 값에 repr() 을 호출하고, '!a' 는 값에 ascii() 를 호출합니다.

몇 가지 예:

"Harold's a clever {0!s}"        # Calls str() on the argument first
"Bring out the holy {name!r}"    # Calls repr() on the argument first
"More {!a}"                      # Calls ascii() on the argument first

format_spec 필드에는 값을 표시하는 방법에 대한 명세가 포함되어 있는데, 필드 너비, 정렬, 채움, 십진 정밀도 등이 포함됩니다. 각 값 형은 자체 “포매팅 미니 언어” 또는 format_spec 의 해석을 정의 할 수 있습니다.

대부분의 내장형은 다음 절에서 설명하는 공통 포매팅 미니 언어를 지원합니다.

A format_spec 필드는 그 안에 중첩된 치환 필드를 포함할 수도 있습니다. 이러한 중첩 된 치환 필드에는 필드 이름, 변환 플래그 및 포맷 명세가 포함될 수 있지만, 더 깊은 중첩은 허용되지 않습니다. format_spec 내의 치환 필드는 format_spec 문자열이 해석되기 전에 치환됩니다. 이렇게 해서 값의 포매팅을 동적으로 지정할 수 있게 합니다.

몇 가지 예제는 포맷 예제 섹션을 보십시오.

포맷 명세 미니 언어

“포맷 명세” 는 포맷 문자열에 포함된 치환 필드 내에서 개별 값의 표시 방법을 정의하는 데 사용됩니다 (포맷 문자열 문법 과 f-strings을 보세요). 이것들은 내장 format() 함수에 직접 전달될 수도 있습니다. 각 포맷 가능한 형은 포맷 명세를 해석하는 방법을 정의 할 수 있습니다.

대부분의 내장형은 포맷 명세에 대해 다음 옵션을 구현하지만, 일부 포맷 옵션은 숫자 형에서만 지원됩니다.

일반적인 관례는 빈 포맷 명세가 값에 str() 을 호출한 것과 같은 결과를 만드는 것입니다. 비어 있지 않은 포맷 명세는 보통 결과를 수정합니다.

표준 포맷 지정자 의 일반적인 형식은 다음과 같습니다:

format_spec     ::=  [[fill]align][sign]["z"]["#"]["0"][width][grouping_option]["." precision][type]
fill            ::=  <any character>
align           ::=  "<" | ">" | "=" | "^"
sign            ::=  "+" | "-" | " "
width           ::=  digit+
grouping_option ::=  "_" | ","
precision       ::=  digit+
type            ::=  "b" | "c" | "d" | "e" | "E" | "f" | "F" | "g" | "G" | "n" | "o" | "s" | "x" | "X" | "%"

유효한 align 값이 지정되면, fill 문자가 앞에 나올 수 있는데 임의의 문자가 될 수 있고, 생략된 경우에는 스페이스가 기본값으로 사용됩니다. 포맷 문자열 리터럴 에서나 str.format() 메서드를 사용할 때는, 리터럴 중괄호(”{” 또는 “}”)를 fill 문자로 사용할 수 없습니다. 그러나, 중첩된 치환 필드로 중괄호를 삽입 할 수 있습니다. 이 제한은 format() 함수에는 영향을 미치지 않습니다.

다양한 정렬 옵션의 의미는 다음과 같습니다:

옵션

의미

'<'

사용 가능한 공간 내에서 필드가 왼쪽 정렬되도록 합니다 (대부분 객체에서 이것이 기본값입니다).

'>'

사용 가능한 공간 내에서 필드가 오른쪽 정렬되도록 합니다 (숫자에서 이것이 기본값입니다).

'='

Forces the padding to be placed after the sign (if any) but before the digits. This is used for printing fields in the form ‘+000000120’. This alignment option is only valid for numeric types, excluding complex. It becomes the default for numbers when ‘0’ immediately precedes the field width.

'^'

사용 가능한 공간 내에서 필드를 가운데에 배치합니다.

최소 필드 너비가 정의되지 않으면, 필드 너비는 항상 필드를 채울 데이터와 같은 크기이므로, 정렬 옵션은 이 경우 의미가 없습니다.

sign 옵션은 숫자 형에게만 유효하며, 다음 중 하나일 수 있습니다:

옵션

의미

'+'

음수뿐만 아니라 양수에도 부호를 사용해야 함을 나타냅니다.

'-'

음수에 대해서만 부호를 사용해야 함을 나타냅니다 (이것이 기본 동작입니다).

스페이스

양수에는 선행 스페이스를 사용하고, 음수에는 마이너스 부호를 사용해야 함을 나타냅니다.

The 'z' option coerces negative zero floating-point values to positive zero after rounding to the format precision. This option is only valid for floating-point presentation types.

버전 3.11에서 변경: Added the 'z' option (see also PEP 682 [https://peps.python.org/pep-0682/]).

The '#' option causes the “alternate form” to be used for the conversion. The alternate form is defined differently for different types. This option is only valid for integer, float and complex types. For integers, when binary, octal, or hexadecimal output is used, this option adds the respective prefix '0b', '0o', '0x', or '0X' to the output value. For float and complex the alternate form causes the result of the conversion to always contain a decimal-point character, even if no digits follow it. Normally, a decimal-point character appears in the result of these conversions only if a digit follows it. In addition, for 'g' and 'G' conversions, trailing zeros are not removed from the result.

',' 옵션은 천 단위 구분 기호에 쉼표를 사용하도록 알립니다. 로케일을 고려하는 구분자의 경우, 대신 'n' 정수 표시 유형을 사용하십시오.

버전 3.1에서 변경: ',' 옵션을 추가했습니다 (PEP 378 [https://peps.python.org/pep-0378/] 도 보세요).

The '_' option signals the use of an underscore for a thousands separator for floating-point presentation types and for integer presentation type 'd'. For integer presentation types 'b', 'o', 'x', and 'X', underscores will be inserted every 4 digits. For other presentation types, specifying this option is an error.

버전 3.6에서 변경: '_' 옵션을 추가했습니다 (PEP 515 [https://peps.python.org/pep-0515/] 도 보세요).

width 는 최소 총 필드 너비를 정의하는 십진 정수인데, 접두사, 구분자 및 다른 포매팅 문자들을 포함합니다. 지정하지 않으면, 필드 너비는 내용에 의해 결정됩니다.

When no explicit alignment is given, preceding the width field by a zero ('0') character enables sign-aware zero-padding for numeric types, excluding complex. This is equivalent to a fill character of '0' with an alignment type of '='.

버전 3.10에서 변경: Preceding the width field by '0' no longer affects the default alignment for strings.

The precision is a decimal integer indicating how many digits should be displayed after the decimal point for presentation types 'f' and 'F', or before and after the decimal point for presentation types 'g' or 'G'. For string presentation types the field indicates the maximum field size - in other words, how many characters will be used from the field content. The precision is not allowed for integer presentation types.

마지막으로 type 은 데이터를 표시하는 방법을 결정합니다.

사용 가능한 문자열 표시 유형은 다음과 같습니다:

유형

의미

's'

문자열 포맷. 이것은 문자열의 기본 유형이고 생략될 수 있습니다.

없음

's' 와 같습니다.

사용 가능한 정수 표시 유형은 다음과 같습니다:

유형

의미

'b'

이진 형식. 이진법으로 숫자를 출력합니다.

'c'

문자. 인쇄하기 전에 정수를 해당 유니코드 문자로 변환합니다.

'd'

십진 정수. 십진법으로 숫자를 출력합니다.

'o'

8진 형식. 8진법으로 숫자를 출력합니다.

'x'

16진 형식. 9보다 큰 숫자의 경우 소문자를 사용하여 16진법으로 숫자를 출력합니다.

'X'

Hex format. Outputs the number in base 16, using upper-case letters for the digits above 9. In case '#' is specified, the prefix '0x' will be upper-cased to '0X' as well.

'n'

숫자. 이는 현재 로케일 설정을 사용하여 적절한 숫자 구분 문자를 삽입한다는 점을 제외하고는 'd' 와 같습니다.

없음

'd' 와 같습니다.

In addition to the above presentation types, integers can be formatted with the floating-point presentation types listed below (except 'n' and None). When doing so, float() is used to convert the integer to a floating-point number before formatting.

float 및 Decimal 값에 사용할 수 있는 표시 유형은 다음과 같습니다:

유형

의미

'e'

Scientific notation. For a given precision p, formats the number in scientific notation with the letter ‘e’ separating the coefficient from the exponent. The coefficient has one digit before and p digits after the decimal point, for a total of p + 1 significant digits. With no precision given, uses a precision of 6 digits after the decimal point for float, and shows all coefficient digits for Decimal. If p=0, the decimal point is omitted unless the # option is used.

'E'

과학적 표기법. 구분 문자로 대문자 ‘E’를 사용한다는 것을 제외하고 'e' 와 같습니다.

'f'

Fixed-point notation. For a given precision p, formats the number as a decimal number with exactly p digits following the decimal point. With no precision given, uses a precision of 6 digits after the decimal point for float, and uses a precision large enough to show all coefficient digits for Decimal. If p=0, the decimal point is omitted unless the # option is used.

'F'

고정 소수점 표기법. 'f' 와 같지만, nan 을 NAN 으로, inf 를 INF 로 변환합니다.

'g'

범용 형식. 주어진 정밀도 p >= 1 에 대해, 숫자를 유효 숫자 p 로 자리 올림 한 다음, 결과를 크기에 따라 고정 소수점 형식이나 과학 표기법으로 포맷합니다. 정밀도 0은 정밀도 1과 동등하게 처리됩니다.

정확한 규칙은 다음과 같습니다: 표시 유형 'e' 와 정밀도 p-1 로 포맷된 결과의 지수가 exp 라고 가정하십시오. 이때 -m <= exp < p 이면 (여기서 m은 float에서 -4이고 Decimal 이면 -6입니다), 숫자는 표시 형식 'f' 와 정밀도 p-1-exp 로 포맷됩니다. 그렇지 않으면, 숫자는 표시 유형 'e' 와 정밀도 p-1 로 포맷됩니다. 두 경우 유효하지 않은 후행 0은 모두 유효숫자부에서 제거되고, 뒤에 남아있는 숫자가 없다면 '#' 옵션이 사용되지 않는 한 소수점도 제거됩니다.

정밀도가 지정되지 않으면, float의 경우 6 유효 자릿수의 정밀도를 사용합니다. Decimal의 경우, 결과 계수는 값의 계수 숫자로 구성됩니다; 과학적 표기법은 절댓값이 1e-6 보다 작은 값과 최하위 숫자의 자릿값이 1보다 큰 값에 사용되며, 그렇지 않으면 고정 소수점 표기법이 사용됩니다.

양과 음의 무한대, 양과 음의 0, nans는 정밀도와 무관하게 각각 inf, -inf, 0, -0, nan 으로 포맷됩니다.

'G'

범용 형식. 숫자가 너무 커지면 'E' 로 전환하는 것을 제외하고 'g' 와 같습니다. 무한과 NaN 의 표현도 대문자로 바뀝니다.

'n'

숫자. 현재 로케일 설정을 사용하여 적절한 숫자 구분 문자를 삽입한다는 점을 제외하면 'g' 와 같습니다.

'%'

백분율. 숫자에 100을 곱해서 고정 ('f') 형식으로 표시한 다음 백분율 기호를 붙입니다.

없음

For float this is like the 'g' type, except that when fixed-point notation is used to format the result, it always includes at least one digit past the decimal point, and switches to the scientific notation when exp >= p - 1. When the precision is not specified, the latter will be as large as needed to represent the given value faithfully.

Decimal의 경우, 현재 십진 컨텍스트의 context.capitals 값에 따라 'g'나 'G'와 같습니다.

전체적인 효과는 str() 의 출력을 다른 포맷 수정자에 의해 변경된 것처럼 만드는 것입니다.

The result should be correctly rounded to a given precision p of digits after the decimal point. The rounding mode for float matches that of the round() builtin. For Decimal, the rounding mode of the current context will be used.

The available presentation types for complex are the same as those for float ('%' is not allowed). Both the real and imaginary components of a complex number are formatted as floating-point numbers, according to the specified presentation type. They are separated by the mandatory sign of the imaginary part, the latter being terminated by a j suffix. If the presentation type is missing, the result will match the output of str() (complex numbers with a non-zero real part are also surrounded by parentheses), possibly altered by other format modifiers.

포맷 예제

이 절은 str.format() 문법의 예와 예전 %-포매팅과의 비교를 포함합니다.

대부분은 문법이 예전의 %-포매팅과 유사하며, {} 가 추가되고 % 대신 및 : 이 사용됩니다. 예를 들어, '%03.2f' 는 '{:03.2f}' 로 번역될 수 있습니다.

새 포맷 문법은 다음 예제에 보이는 것과 같이 새롭고 다양한 옵션도 지원합니다.

위치로 인자 액세스:

>>> '{0}, {1}, {2}'.format('a', 'b', 'c')
'a, b, c'
>>> '{}, {}, {}'.format('a', 'b', 'c')  # 3.1+ only
'a, b, c'
>>> '{2}, {1}, {0}'.format('a', 'b', 'c')
'c, b, a'
>>> '{2}, {1}, {0}'.format(*'abc')      # unpacking argument sequence
'c, b, a'
>>> '{0}{1}{0}'.format('abra', 'cad')   # arguments' indices can be repeated
'abracadabra'

이름으로 인자 액세스:

>>> 'Coordinates: {latitude}, {longitude}'.format(latitude='37.24N', longitude='-115.81W')
'Coordinates: 37.24N, -115.81W'
>>> coord = {'latitude': '37.24N', 'longitude': '-115.81W'}
>>> 'Coordinates: {latitude}, {longitude}'.format(**coord)
'Coordinates: 37.24N, -115.81W'

인자의 어트리뷰트 액세스:

>>> c = 3-5j
>>> ('The complex number {0} is formed from the real part {0.real} '
...  'and the imaginary part {0.imag}.').format(c)
'The complex number (3-5j) is formed from the real part 3.0 and the imaginary part -5.0.'
>>> class Point:
...     def __init__(self, x, y):
...         self.x, self.y = x, y
...     def __str__(self):
...         return 'Point({self.x}, {self.y})'.format(self=self)
...
>>> str(Point(4, 2))
'Point(4, 2)'

인자의 항목 액세스:

>>> coord = (3, 5)
>>> 'X: {0[0]};  Y: {0[1]}'.format(coord)
'X: 3;  Y: 5'

%s 과 %r 대체:

>>> "repr() shows quotes: {!r}; str() doesn't: {!s}".format('test1', 'test2')
"repr() shows quotes: 'test1'; str() doesn't: test2"

텍스트 정렬과 너비 지정:

>>> '{:<30}'.format('left aligned')
'left aligned                  '
>>> '{:>30}'.format('right aligned')
'                 right aligned'
>>> '{:^30}'.format('centered')
'           centered           '
>>> '{:*^30}'.format('centered')  # use '*' as a fill char
'***********centered***********'

%+f, %-f, % f 대체와 부호 지정:

>>> '{:+f}; {:+f}'.format(3.14, -3.14)  # show it always
'+3.140000; -3.140000'
>>> '{: f}; {: f}'.format(3.14, -3.14)  # show a space for positive numbers
' 3.140000; -3.140000'
>>> '{:-f}; {:-f}'.format(3.14, -3.14)  # show only the minus -- same as '{:f}; {:f}'
'3.140000; -3.140000'

%x, %o 대체와 다른 진법으로 값 변환:

>>> # format also supports binary numbers
>>> "int: {0:d};  hex: {0:x};  oct: {0:o};  bin: {0:b}".format(42)
'int: 42;  hex: 2a;  oct: 52;  bin: 101010'
>>> # with 0x, 0o, or 0b as prefix:
>>> "int: {0:d};  hex: {0:#x};  oct: {0:#o};  bin: {0:#b}".format(42)
'int: 42;  hex: 0x2a;  oct: 0o52;  bin: 0b101010'

쉼표를 천 단위 구분자로 사용:

>>> '{:,}'.format(1234567890)
'1,234,567,890'

백분율 표현:

>>> points = 19
>>> total = 22
>>> 'Correct answers: {:.2%}'.format(points/total)
'Correct answers: 86.36%'

형별 포매팅 사용:

>>> import datetime
>>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)
>>> '{:%Y-%m-%d %H:%M:%S}'.format(d)
'2010-07-04 12:15:58'

인자 중첩과 보다 복잡한 예제:

>>> for align, text in zip('<^>', ['left', 'center', 'right']):
...     '{0:{fill}{align}16}'.format(text, fill=align, align=align)
...
'left<<<<<<<<<<<<'
'^^^^^center^^^^^'
'>>>>>>>>>>>right'
>>>
>>> octets = [192, 168, 0, 1]
>>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)
'C0A80001'
>>> int(_, 16)
3232235521
>>>
>>> width = 5
>>> for num in range(5,12):
...     for base in 'dXob':
...         print('{0:{width}{base}}'.format(num, base=base, width=width), end=' ')
...     print()
...
    5     5     5   101
    6     6     6   110
    7     7     7   111
    8     8    10  1000
    9     9    11  1001
   10     A    12  1010
   11     B    13  1011

템플릿 문자열

Template strings provide simpler string substitutions as described in PEP 292 [https://peps.python.org/pep-0292/]. A primary use case for template strings is for internationalization (i18n) since in that context, the simpler syntax and functionality makes it easier to translate than other built-in string formatting facilities in Python. As an example of a library built on template strings for i18n, see the flufl.i18n [https://flufli18n.readthedocs.io/en/latest/] package.

템플릿 문자열은 다음 규칙을 사용하여 $-기반 치환을 지원합니다:

$$ 는 이스케이프입니다. 이것은 하나의 $ 로 치환됩니다.

$identifier 는 매핑 키 "identifier" 와 일치하는 치환 자리 표시자를 지정합니다. 기본적으로, "identifier" 는 밑줄이나 ASCII 알파벳으로 시작하는 대소문자 구분 없는 ASCII 영숫자(밑줄 포함) 문자열로 제한됩니다. $ 문자 뒤의 첫 번째 비 식별자 문자는 이 자리 표시자 명세를 종료합니다.

${identifier} 는 $identifier 와 동등합니다. 유효한 식별자 문자가 자리 표시자 뒤에 오지만, 자리 표시자의 일부가 아니면 필요합니다, 가령 "${noun}ification".

문자열에 다른 방식으로 $ 이 등장하면 ValueError 가 발생합니다.

string 모듈은 이 규칙들을 구현하는 Template 클래스를 제공합니다. Template 의 메서드는 다음과 같습니다:

class string.Template(template)

생성자는 템플릿 문자열 하나를 받아들입니다.

substitute(mapping={}, /, **kwds)

템플릿 치환을 수행하고, 새 문자열을 반환합니다. mapping 은 템플릿의 자리 표시자와 일치하는 키를 가진 임의의 딕셔너리류 객체입니다. 또는, 키워드가 자리 표시자인 키워드 인자를 제공 할 수 있습니다. mapping 및 kwds 가 모두 제공되고 중복이 있는 경우, kwds 의 자리 표시자가 우선합니다.

safe_substitute(mapping={}, /, **kwds)

substitute()와 비슷하지만, mapping 과 kwds 에 자리 표시자가 없는 경우, KeyError 예외를 발생시키지 않고 원래 자리 표시자가 결과 문자열에 그대로 나타납니다. 또한 substitute() 와는 달리, $ 가 잘못 사용되는 경우 ValueError 를 일으키는 대신 단순히 $ 를 반환합니다.

다른 예외가 여전히 발생할 수 있지만, 이 메서드가 항상 예외를 발생시키는 대신 사용 가능한 문자열을 반환하려고 시도하기 때문에 “안전(safe)” 하다고 합니다. 다른 의미에서, safe_substitute() 는 안전하다고 할 수 없습니다. 길 잃은(dangling) 구분 기호, 쌍을 이루지 않는 중괄호, 유효한 파이썬 식별자가 아닌 자리 표시자를 포함하는 잘못된 템플릿을 조용히 무시하기 때문입니다.

is_valid()

Returns false if the template has invalid placeholders that will cause substitute() to raise ValueError.

Added in version 3.11.

get_identifiers()

Returns a list of the valid identifiers in the template, in the order they first appear, ignoring any invalid identifiers.

Added in version 3.11.

Template 인스턴스는 공개 데이터 어트리뷰트도 하나 제공합니다:

template

이것은 생성자의 template 인자로 전달된 객체입니다. 일반적으로, 변경해서는 안 되지만, 읽기 전용 액세스가 강제되지는 않습니다.

다음은 Template 사용 방법의 예입니다:

>>> from string import Template
>>> s = Template('$who likes $what')
>>> s.substitute(who='tim', what='kung pao')
'tim likes kung pao'
>>> d = dict(who='tim')
>>> Template('Give $who $100').substitute(d)
Traceback (most recent call last):
...
ValueError: Invalid placeholder in string: line 1, col 11
>>> Template('$who likes $what').substitute(d)
Traceback (most recent call last):
...
KeyError: 'what'
>>> Template('$who likes $what').safe_substitute(d)
'tim likes $what'

고급 사용법: Template 의 서브 클래스를 파생하여, 자리 표시자 문법, 구분 기호 문자 또는 템플릿 문자열을 파싱하는데 사용되는 전체 정규식을 사용자 정의 할 수 있습니다. 이렇게 하려면, 다음 클래스 어트리뷰트를 재정의할 수 있습니다:

delimiter – 자리 표시자를 도입하는 구분자를 나타내는 리터럴 문자열입니다. 기본값은 $ 입니다. 구현체는 필요할 때 이 문자열에 re.escape() 를 호출하므로, 이 문자열은 정규식이 아니어야 합니다. 또한, 클래스 생성 후에 구분자를 변경할 수 없습니다 (즉, 다른 구분자는 반드시 서브 클래스의 클래스 이름 공간에 설정해야 합니다).

idpattern – 중괄호로 둘러싸지 않은 자리 표시자의 패턴을 설명하는 정규식입니다. 기본값은 정규식 (?a:[_a-z][_a-z0-9]*) 입니다. braceidpattern 이 None 인 경우, 이 패턴은 중괄호가 있는 자리 표시자에게도 적용됩니다.

참고

기본 flags 가 re.IGNORECASE 이기 때문에, 패턴 [a-z] 는 비 ASCII 문자와 일치 할 수 있습니다. 이 때문에 정규식에 a 플래그를 사용했습니다.

버전 3.7에서 변경: braceidpattern 은 중괄호로 싸여있을 때와 그렇지 않을 때 사용되는 별도의 패턴을 정의하는데 사용할 수 있습니다.

braceidpattern – idpattern 과 유사하지만, 중괄호로 싸인 자리 표시자에 대한 패턴을 설명합니다. 기본값은 None 인데, idpattern 을 사용하는 것을 의미합니다 (즉, 같은 패턴이 중괄호가 있을 때와 없을 때 모두 사용됩니다). 이 값을 주면, 중괄호가 있을 때와 없을 때의 자리 표시자에 서로 다른 패턴을 정의 할 수 있습니다.

Added in version 3.7.

flags – 치환 인식에 사용되는 정규식을 컴파일할 때 적용될 정규식 플래그입니다. 기본값은 re.IGNORECASE 입니다. re.VERBOSE 가 항상 플래그에 추가되므로, 사용자 정의 idpattern 은 상세한 정규식의 규칙을 따라야 합니다.

Added in version 3.2.

또는, 클래스 어트리뷰트 pattern 을 재정의하여 전체 정규식 패턴을 제공 할 수 있습니다. 이렇게 하는 경우, 값은 네 개의 이름있는 캡처 그룹이 있는 정규식 객체여야 합니다. 캡처 그룹은 위에 제공된 규칙과 함께 유효하지 않은 자리 표시자 규칙에 해당합니다:

escaped – 이 그룹은 이스케이프 시퀀스를 일치시킵니다, 예를 들어 기본 패턴에서 $$.

named – 이 그룹은 중괄호가 없는 자리 표시자 이름을 일치합니다; 캡처 그룹에 구분자를 포함해서는 안 됩니다.

braced – 이 그룹은 중괄호로 묶인 자리 표시자 이름을 일치시킵니다; 캡처 그룹에 구분자나 중괄호를 포함해서는 안 됩니다.

invalid – 이 그룹은 그 외의 구분자 패턴(일반적으로 단일 구분자)을 일치시키고, 정규식의 마지막에 나타나야 합니다.

The methods on this class will raise ValueError if the pattern matches the template without one of these named groups matching.

도움 함수

string.capwords(s, sep=None)

인자를 str.split() 을 사용하여 단어로 나누고, str.capitalize() 를 사용하여 각 단어의 첫 글자를 대문자로 만들고, 이렇게 만들어진 단어들을 str.join() 을 사용하여 결합합니다. 선택적 두 번째 인자 sep 가 없거나 None 이면, 연속된 공백 문자는 단일 스페이스로 바뀌고 앞뒤 공백이 제거됩니다. 그렇지 않으면 sep 가 단어를 나누고 합치는 데 사용됩니다.

re — Regular expression operations

Source code: Lib/re/ [https://github.com/python/cpython/tree/main/Lib/re/]

이 모듈은 Perl에 있는 것과 유사한 정규식 일치 연산을 제공합니다.

Both patterns and strings to be searched can be Unicode strings (str) as well as 8-bit strings (bytes). However, Unicode strings and 8-bit strings cannot be mixed: that is, you cannot match a Unicode string with a bytes pattern or vice-versa; similarly, when asking for a substitution, the replacement string must be of the same type as both the pattern and the search string.

Regular expressions use the backslash character ('\') to indicate special forms or to allow special characters to be used without invoking their special meaning. This collides with Python’s usage of the same character for the same purpose in string literals; for example, to match a literal backslash, one might have to write '\\\\' as the pattern string, because the regular expression must be \\, and each backslash must be expressed as \\ inside a regular Python string literal. Also, please note that any invalid escape sequences in Python’s usage of the backslash in string literals now generate a SyntaxWarning and in the future this will become a SyntaxError. This behaviour will happen even if it is a valid escape sequence for a regular expression.

해결책은 정규식 패턴에 파이썬의 날 문자열(raw string) 표기법을 사용하는 것입니다; 역 슬래시는 'r' 접두어가 붙은 문자열 리터럴에서 특별한 방법으로 처리되지 않습니다. 따라서 r"\n"은 '\'와 'n'을 포함하는 두 글자 문자열이고, "\n"은 개행을 포함하는 한 글자 문자열입니다. 일반적으로 패턴은, 이 날 문자열 표기법을 사용하여 파이썬 코드로 표현됩니다.

대부분 정규식 연산은 모듈 수준 함수와 컴파일된 정규식의 메서드로 사용할 수 있다는 점에 유의해야 합니다. 함수는 정규식 객체를 먼저 컴파일할 필요가 없도록 하는 바로 가기이지만, 일부 미세 조정 매개 변수가 빠져있습니다.

더 보기

The third-party regex [https://pypi.org/project/regex/] module, which has an API compatible with the standard library re module, but offers additional functionality and a more thorough Unicode support.

정규식 문법

정규식(또는 RE)은 일치하는 문자열 집합을 지정합니다; 이 모듈의 함수는 특정 문자열이 주어진 정규식과 일치하는지 확인할 수 있도록 합니다 (또는 주어진 정규식이 특정 문자열과 일치하는지, 결국 같은 결과를 줍니다).

정규식을 이어붙여서 새로운 정규식을 만들 수 있습니다; A와 B가 모두 정규식이면 AB도 정규식입니다. 일반적으로 문자열 p가 A와 일치하고 다른 문자열 q가 B와 일치하면 문자열 pq가 AB와 일치합니다. 이것은 A나 B가 우선순위가 낮은 연산, A와 B 사이의 경계 조건 또는 숫자 그룹 참조를 포함하지 않는 한 성립합니다. 따라서, 복잡한 정규식은 여기에 설명된 것과 같은 더 단순한 기본 정규식으로 쉽게 구성할 수 있습니다. 정규식의 이론과 구현에 관한 자세한 내용은 Friedl 책 [Frie09], 또는 컴파일러 작성에 관한 거의 모든 교과서를 참조하십시오.

정규식의 형식에 대한 간단한 설명이 이어집니다. 더 자세한 정보와 더 친절한 소개는 정규식 HOWTO를 참조하십시오.

정규식은 특수 문자와 일반 문자를 모두 포함 할 수 있습니다. 'A', 'a' 또는 '0'과 같은 대부분의 일반 문자는 가장 단순한 정규식입니다; 그들은 단순히 자신과 일치합니다. 일반 문자를 이어 붙일 수 있어서, last는 'last' 문자열과 일치합니다. (이 절의 나머지 부분에서는, RE를 (보통 따옴표 없이) 이런 특별한 스타일로, 일치할 문자열은 '작은따옴표 안에' 씁니다.)

'|'나 '('와 같은 일부 문자는 특수합니다. 특수 문자는 일반 문자의 클래스를 나타내거나, 그 주변의 정규식이 해석되는 방식에 영향을 줍니다.

Repetition operators or quantifiers (*, +, ?, {m,n}, etc) cannot be directly nested. This avoids ambiguity with the non-greedy modifier suffix ?, and with other modifiers in other implementations. To apply a second repetition to an inner repetition, parentheses may be used. For example, the expression (?:a{6})* matches any multiple of six 'a' characters.

특수 문자는 다음과 같습니다:

.

(Dot.) In the default mode, this matches any character except a newline. If the DOTALL flag has been specified, this matches any character including a newline. (?s:.) matches any character regardless of flags.

^

(캐럿.) 문자열의 시작과 일치하고, MULTILINE 모드에서는 각 개행 직후에도 일치합니다.

$

문자열의 끝이나 문자열 끝의 개행 문자 바로 직전과 일치하고, MULTILINE 모드에서는 개행 문자 앞에서도 일치합니다. foo는 ‘foo’와 ‘foobar’를 모두 일치시키는 반면, 정규식 foo$는 ‘foo’ 만 일치합니다. 흥미롭게도, 'foo1\nfoo2\n'에서 foo.$를 검색하면 ‘foo2’ 는 정상적으로 일치되지만, ‘foo1’은 MULTILINE 모드에서 검색됩니다; 'foo\n'에서 단일 $를 검색하면 두 개의 (빈) 일치가 발견됩니다: 하나는 개행 직전에, 다른 하나는 문자열 끝에.

*

결과 RE가 선행 RE의 가능한 한 많은 0회 이상의 반복과 일치하도록 합니다. ab*는 ‘a’, ‘ab’ 또는 ‘a’ 다음에 임의의 수의 ‘b’가 오는 것과 일치합니다.

+

결과 RE가 선행 RE의 1회 이상의 반복과 일치하도록 합니다. ab+는 ‘a’ 다음에 하나 이상의 ‘b’가 오는 것과 일치합니다; 단지 ‘a’와는 일치하지 않습니다.

?

결과 RE가 선행 RE의 0 또는 1 반복과 일치하도록 합니다. ab?는 ‘a’나 ‘ab’와 일치합니다.

*?, +?, ??

The '*', '+', and '?' quantifiers are all greedy; they match as much text as possible. Sometimes this behaviour isn’t desired; if the RE <.*> is matched against '<a> b <c>', it will match the entire string, and not just '<a>'. Adding ? after the quantifier makes it perform the match in non-greedy or minimal fashion; as few characters as possible will be matched. Using the RE <.*?> will match only '<a>'.

*+, ++, ?+

Like the '*', '+', and '?' quantifiers, those where '+' is appended also match as many times as possible. However, unlike the true greedy quantifiers, these do not allow back-tracking when the expression following it fails to match. These are known as possessive quantifiers. For example, a*a will match 'aaaa' because the a* will match all 4 'a's, but, when the final 'a' is encountered, the expression is backtracked so that in the end the a* ends up matching 3 'a's total, and the fourth 'a' is matched by the final 'a'. However, when a*+a is used to match 'aaaa', the a*+ will match all 4 'a', but when the final 'a' fails to find any more characters to match, the expression cannot be backtracked and will thus fail to match. x*+, x++ and x?+ are equivalent to (?>x*), (?>x+) and (?>x?) correspondingly.

Added in version 3.11.

{m}

선행 RE의 정확히 m 복사가 일치하도록 지정합니다; 적은 횟수의 일치는 전체 RE가 일치하지 않게 됩니다. 예를 들어, a{6}는 정확히 6개의 'a' 문자와 일치하지만, 5개의 문자와는 일치하지 않습니다.

{m,n}

결과 RE를 선행 RE의 m에서 n 사이의 최대한 많은 반복과 일치하도록 합니다. 예를 들어, a{3,5}는 3에서 5개의 'a' 문자와 일치합니다. m을 생략하면 하한값 0이 지정되고, n을 생략하면 무한한 상한이 지정됩니다. 예를 들어, a{4,}b는 'aaaab' 나 1000개의 'a' 문자와 'b'가 일치하지만, 'aaab'는 일치하지 않습니다. 콤마는 생략할 수 없습니다, 그렇지 않으면 한정자가 앞에서 설명한 형식과 혼동될 수 있습니다.

{m,n}?

Causes the resulting RE to match from m to n repetitions of the preceding RE, attempting to match as few repetitions as possible. This is the non-greedy version of the previous quantifier. For example, on the 6-character string 'aaaaaa', a{3,5} will match 5 'a' characters, while a{3,5}? will only match 3 characters.

{m,n}+

Causes the resulting RE to match from m to n repetitions of the preceding RE, attempting to match as many repetitions as possible without establishing any backtracking points. This is the possessive version of the quantifier above. For example, on the 6-character string 'aaaaaa', a{3,5}+aa attempt to match 5 'a' characters, then, requiring 2 more 'a's, will need more characters than available and thus fail, while a{3,5}aa will match with a{3,5} capturing 5, then 4 'a's by backtracking and then the final 2 'a's are matched by the final aa in the pattern. x{m,n}+ is equivalent to (?>x{m,n}).

Added in version 3.11.

\

특수 문자를 이스케이프 하거나 ('*', '?' 등의 문자를 일치시킬 수 있도록 합니다), 특수 시퀀스를 알립니다; 특수 시퀀스는 아래에서 설명합니다.

날 문자열을 사용하여 패턴을 표현하지 않는다면, 파이썬이 문자열 리터럴에서 이스케이프 시퀀스로 역 슬래시를 사용한다는 것을 기억하십시오; 이스케이프 시퀀스가 파이썬의 구문 분석기에 의해 인식되지 않으면, 역 슬래시와 후속 문자가 결과 문자열에 포함됩니다. 그러나 파이썬이 결과 시퀀스를 인식한다면 역 슬래시는 두 번 반복되어야 합니다. 이것은 복잡하고 이해하기 어렵기 때문에, 가장 단순한 표현 이외에는 날 문자열을 사용하는 것이 좋습니다.

[]

문자 집합을 나타내는 데 사용됩니다. 집합 안에서:

문자는 개별적으로 나열 할 수 있습니다, 예를 들어 [amk]는 'a', 'm' 또는 'k'와 일치합니다.

문자의 범위는 '-'로 구분된 두 문자를 주고는 것으로 나타낼 수 있습니다, 예를 들어 [a-z]는 모든 소문자 ASCII 문자와 일치하고, [0-5][0-9]는 00에서 59까지의 모든 두 자리 숫자와 일치하며, [0-9A-Fa-f]는 모든 16진수와 일치합니다. -가 이스케이프 처리되거나 (예를 들어 [a\-z]) 첫 번째나 마지막 문자로 배치되면 (예를 들어 [-a]나 [a-]) 리터럴 '-'와 일치합니다.

특수 문자는 집합 내에서 특별한 의미를 상실합니다. 예를 들어, [(+*)]는 리터럴 문자 '(', '+', '*' 또는 ')'와 일치합니다.

Character classes such as \w or \S (defined below) are also accepted inside a set, although the characters they match depend on the flags used.

범위 내에 있지 않은 문자는 여집합(complementing)을 만들어 일치할 수 있습니다. 집합의 첫 번째 문자가 '^'이면, 집합에 속하지 않은 모든 문자가 일치합니다. 예를 들어, [^5]는 '5'를 제외한 모든 문자와 일치하며, [^^]는 '^'를 제외한 모든 문자와 일치합니다. ^는 집합의 첫 번째 문자가 아닐 때 특별한 의미가 없습니다.

To match a literal ']' inside a set, precede it with a backslash, or place it at the beginning of the set. For example, both [()[\]{}] and []()[{}] will match a right bracket, as well as left bracket, braces, and parentheses.

유니코드 기술 표준 #18 [https://unicode.org/reports/tr18/] 에서 정의하는 중첩 집합과 집합 연산의 지원이 다음에 추가될 수 있습니다. 이것은 문법을 변경하므로, 이 변경을 용이하게 하기 위해 당분간 FutureWarning이 모호한 경우에 발생합니다. 여기에는 리터럴 '['로 시작하거나 리터럴 문자 시퀀스 '--', '&&', '~~' 및 '||'가 포함된 집합이 포함됩니다. 경고를 피하려면 역 슬래시로 이스케이프 처리하십시오.

버전 3.7에서 변경: 문자 집합이 미래에 의미가 변할 구조를 포함하고 있다면 FutureWarning이 발생합니다.

|

A|B(여기서 A와 B는 임의의 RE일 수 있습니다)는 A나 B와 일치하는 정규식을 만듭니다. 이러한 방식으로 임의의 수의 RE를 '|'로 분리 할 수 있습니다. 이것은 그룹(아래를 참조하세요)에서도 사용할 수 있습니다. 대상 문자열이 스캔 될 때 '|'로 구분된 RE는 왼쪽에서 오른쪽으로 시도됩니다. 한 패턴이 완전히 일치하면, 해당 분기가 받아들여집니다. 이는 일단 A가 일치하면, B는 전체적으로 더 긴 일치를 생성하더라도 더 검사되지 않는다는 것을 뜻합니다. 즉, '|' 연산자는 절대로 탐욕적이지 않습니다. 리터럴 '|'와 일치시키려면, \|를 사용하거나, [|]처럼 문자 클래스 안에 넣으십시오.

(...)

괄호 안에 있는 정규식과 일치하며, 그룹의 시작과 끝을 나타냅니다; 그룹의 내용은 일치가 수행된 후 조회할 수 있으며, 나중에 문자열에서 \number 특수 시퀀스로 일치시킬 수 있습니다 (아래에서 설명됩니다). 리터럴 '('나 ')'를 일치시키려면, \(나 \)를 사용하거나, 문자 클래스 안에 넣으십시오: [(], [)].

(?...)

이것은 확장 표기법입니다 (그렇지 않으면 '(' 다음에 오는 '?'``는 의미가 없습니다). ``'?' 다음의 첫 번째 문자는 확장의 의미와 이후의 문법을 결정합니다. 확장은 대개 새 그룹을 만들지 않습니다; 이 규칙에 대한 유일한 예외는 (?P<name>...)입니다. 다음은 현재 지원되는 확장입니다.

(?aiLmsux)

(One or more letters from the set 'a', 'i', 'L', 'm', 's', 'u', 'x'.) The group matches the empty string; the letters set the corresponding flags for the entire regular expression:

re.A (ASCII-only matching)

re.I (ignore case)

re.L (locale dependent)

re.M (multi-line)

re.S (dot matches all)

re.U (Unicode matching)

re.X (verbose)

(The flags are described in 모듈 내용.) This is useful if you wish to include the flags as part of the regular expression, instead of passing a flag argument to the re.compile() function. Flags should be used first in the expression string.

버전 3.11에서 변경: This construction can only be used at the start of the expression.

(?:...)

일반 괄호의 비 포착 버전. 괄호 안의 정규식과 일치하지만, 그룹과 일치하는 부분 문자열은 일치를 수행한 후 조회하거나 나중에 패턴에서 참조할 수 없습니다.

(?aiLmsux-imsx:...)

(Zero or more letters from the set 'a', 'i', 'L', 'm', 's', 'u', 'x', optionally followed by '-' followed by one or more letters from the 'i', 'm', 's', 'x'.) The letters set or remove the corresponding flags for the part of the expression:

re.A (ASCII-only matching)

re.I (ignore case)

re.L (locale dependent)

re.M (multi-line)

re.S (dot matches all)

re.U (Unicode matching)

re.X (verbose)

(The flags are described in 모듈 내용.)

The letters 'a', 'L' and 'u' are mutually exclusive when used as inline flags, so they can’t be combined or follow '-'. Instead, when one of them appears in an inline group, it overrides the matching mode in the enclosing group. In Unicode patterns (?a:...) switches to ASCII-only matching, and (?u:...) switches to Unicode matching (default). In bytes patterns (?L:...) switches to locale dependent matching, and (?a:...) switches to ASCII-only matching (default). This override is only in effect for the narrow inline group, and the original matching mode is restored outside of the group.

Added in version 3.6.

버전 3.7에서 변경: 문자 'a', 'L' 및 'u'도 그룹에서 사용할 수 있습니다.

(?>...)

Attempts to match ... as if it was a separate regular expression, and if successful, continues to match the rest of the pattern following it. If the subsequent pattern fails to match, the stack can only be unwound to a point before the (?>...) because once exited, the expression, known as an atomic group, has thrown away all stack points within itself. Thus, (?>.*). would never match anything because first the .* would match all characters possible, then, having nothing left to match, the final . would fail to match. Since there are no stack points saved in the Atomic Group, and there is no stack point before it, the entire expression would thus fail to match.

Added in version 3.11.

(?P<name>...)

Similar to regular parentheses, but the substring matched by the group is accessible via the symbolic group name name. Group names must be valid Python identifiers, and in bytes patterns they can only contain bytes in the ASCII range. Each group name must be defined only once within a regular expression. A symbolic group is also a numbered group, just as if the group were not named.

이름 있는 그룹은 세 가지 문맥에서 참조될 수 있습니다. 패턴이 (?P<quote>['"]).*?(?P=quote)면 (즉, 작은따옴표나 큰따옴표로 인용된 문자열과 일치):

그룹 “quote”에 대한 참조 문맥

참조하는 방법

같은 패턴 자체에서

(?P=quote) (보이는 대로)

\1

일치 객체 m을 처리할 때

m.group('quote')

m.end('quote') (등)

re.sub()의 repl 인자로 전달되는 문자열에서

\g<quote>

\g<1>

\1

버전 3.12에서 변경: In bytes patterns, group name can only contain bytes in the ASCII range (b'\x00'-b'\x7f').

(?P=name)

이름있는 그룹에 대한 역참조; name이라는 이름의 앞선 그룹과 일치하는 텍스트와 일치합니다.

(?#...)

주석; 괄호의 내용은 단순히 무시됩니다.

(?=...)

...가 다음과 일치하면 일치하지만, 문자열을 소비하지는 않습니다. 이를 미리 보기 어서션 (lookahead assertion)이라고 합니다. 예를 들어, Isaac (?=Asimov)는 'Asimov'가 뒤따를 때만 'Isaac '과 일치합니다.

(?!...)

...가 다음과 일치하지 않으면 일치합니다. 이것은 부정적인 미리 보기 어서션 (negative lookahead assertion)입니다. 예를 들어, Isaac (?!Asimov)는 'Asimov'가 뒤따르지 않을 때 만 'Isaac '과 일치합니다.

(?<=...)

문자열의 현재 위치 앞에 현재 위치에서 끝나는 ...와의 일치가 있으면 일치합니다. 이를 긍정적인 되돌아보기 어서션 (positive lookbehind assertion)이라고 합니다. 되돌아보기가 3문자를 백업하고 포함된 패턴이 일치하는지 확인하기 때문에 (?<=abc)def는 'abcdef'에서 일치를 찾습니다. 포함된 패턴은 고정 길이의 문자열과 일치해야 합니다, 즉, abc나 a|b는 허용되지만, a*와 a{3,4}는 허용되지 않습니다. 긍정적인 되돌아보기 어서션으로 시작하는 패턴은 검색되는 문자열의 시작 부분에서 일치하지 않음에 유의하십시오; match() 함수보다는 search() 함수를 사용하기를 원할 것입니다:

>>> import re
>>> m = re.search('(?<=abc)def', 'abcdef')
>>> m.group(0)
'def'

이 예에서는 하이픈 다음의 단어를 찾습니다:

>>> m = re.search(r'(?<=-)\w+', 'spam-egg')
>>> m.group(0)
'egg'

버전 3.5에서 변경: 고정 길이의 그룹 참조에 대한 지원이 추가되었습니다.

(?<!...)

문자열의 현재 위치 앞에 ...와의 일치가 없으면 일치합니다. 이를 부정적인 뒤돌아보기 어서션 (negative lookbehind assertion)이라고 합니다. 긍정적인 뒤돌아보기 어서션과 마찬가지로, 포함된 패턴은 고정 길이의 문자열과 일치해야 합니다. 부정적인 뒤돌아보기 어서션으로 시작하는 패턴은 검색되는 문자열의 시작 부분에서 일치 할 수 있습니다.

(?(id/name)yes-pattern|no-pattern)

주어진 id나 name의 그룹이 있으면 yes-pattern과, 그렇지 않으면 no-pattern과 일치하려고 시도합니다. no-pattern은 선택적이며 생략될 수 있습니다. 예를 들어, (<)?(\w+@\w+(?:\.\w+)+)(?(1)>|$)는 정교하지 않은 전자 메일 일치 패턴인데, '<user@host.com>' 및 'user@host.com'과 일치하지만, '<user@host.com'이나 'user@host.com>'과는 일치하지 않습니다.

버전 3.12에서 변경: Group id can only contain ASCII digits. In bytes patterns, group name can only contain bytes in the ASCII range (b'\x00'-b'\x7f').

특수 시퀀스는 '\'와 아래 목록의 문자로 구성됩니다. 일반 문자가 ASCII 숫자나 ASCII 글자가 아니면, 결과 RE는 두 번째 문자와 일치합니다. 예를 들어, \$는 문자 '$'와 일치합니다.

\number

같은 번호의 그룹 내용과 일치합니다. 그룹은 1부터 번호가 매겨집니다. 예를 들어, (.+) \1은 'the the'나 '55 55'와 일치하지만, 'thethe'와는 일치하지 않습니다 (그룹 뒤의 공백에 유의하십시오). 이 특수 시퀀스는 첫 99개 그룹 중 하나와 일치하는 데에만 사용될 수 있습니다. number의 첫 자릿수가 0이거나, number가 3 자릿수면, 그룹 일치로 해석되지 않고, 8진수 값 number를 갖는 문자로 해석됩니다. 문자 클래스의 '['와 ']' 안에서는, 모든 숫자 이스케이프가 문자로 처리됩니다.

\A

문자열의 시작 부분에서만 일치합니다.

\b

Matches the empty string, but only at the beginning or end of a word. A word is defined as a sequence of word characters. Note that formally, \b is defined as the boundary between a \w and a \W character (or vice versa), or between \w and the beginning or end of the string. This means that r'\bat\b' matches 'at', 'at.', '(at)', and 'as at ay' but not 'attempt' or 'atlas'.

The default word characters in Unicode (str) patterns are Unicode alphanumerics and the underscore, but this can be changed by using the ASCII flag. Word boundaries are determined by the current locale if the LOCALE flag is used.

참고

Inside a character range, \b represents the backspace character, for compatibility with Python’s string literals.

\B

Matches the empty string, but only when it is not at the beginning or end of a word. This means that r'at\B' matches 'athens', 'atom', 'attorney', but not 'at', 'at.', or 'at!'. \B is the opposite of \b, so word characters in Unicode (str) patterns are Unicode alphanumerics or the underscore, although this can be changed by using the ASCII flag. Word boundaries are determined by the current locale if the LOCALE flag is used.

참고

Note that \B does not match an empty string, which differs from RE implementations in other programming languages such as Perl. This behavior is kept for compatibility reasons.

\d

유니코드 (str) 패턴일 때:

Matches any Unicode decimal digit (that is, any character in Unicode character category [Nd] [https://www.unicode.org/versions/Unicode15.0.0/ch04.pdf#G134153]). This includes [0-9], and also many other digit characters.

Matches [0-9] if the ASCII flag is used.

8비트 (bytes) 패턴일 때:

Matches any decimal digit in the ASCII character set; this is equivalent to [0-9].

\D

Matches any character which is not a decimal digit. This is the opposite of \d.

Matches [^0-9] if the ASCII flag is used.

\s

유니코드 (str) 패턴일 때:

Matches Unicode whitespace characters (as defined by str.isspace()). This includes [ \t\n\r\f\v], and also many other characters, for example the non-breaking spaces mandated by typography rules in many languages.

Matches [ \t\n\r\f\v] if the ASCII flag is used.

8비트 (bytes) 패턴일 때:

ASCII 문자 집합에서 공백으로 간주하는 문자와 일치합니다; 이것은 [ \t\n\r\f\v]와 동등합니다.

\S

Matches any character which is not a whitespace character. This is the opposite of \s.

Matches [^ \t\n\r\f\v] if the ASCII flag is used.

\w

유니코드 (str) 패턴일 때:

Matches Unicode word characters; this includes all Unicode alphanumeric characters (as defined by str.isalnum()), as well as the underscore (_).

Matches [a-zA-Z0-9_] if the ASCII flag is used.

8비트 (bytes) 패턴일 때:

Matches characters considered alphanumeric in the ASCII character set; this is equivalent to [a-zA-Z0-9_]. If the LOCALE flag is used, matches characters considered alphanumeric in the current locale and the underscore.

\W

Matches any character which is not a word character. This is the opposite of \w. By default, matches non-underscore (_) characters for which str.isalnum() returns False.

Matches [^a-zA-Z0-9_] if the ASCII flag is used.

If the LOCALE flag is used, matches characters which are neither alphanumeric in the current locale nor the underscore.

\Z

문자열 끝에만 일치합니다.

Most of the escape sequences supported by Python string literals are also accepted by the regular expression parser:

\a      \b      \f      \n
\N      \r      \t      \u
\U      \v      \x      \\

(\b는 단어 경계를 나타내는 데 사용되며, 문자 클래스 내에서만 “백스페이스”를 의미함에 유의하십시오.)

'\u', '\U', and '\N' escape sequences are only recognized in Unicode (str) patterns. In bytes patterns they are errors. Unknown escapes of ASCII letters are reserved for future use and treated as errors.

8진수 이스케이프는 제한된 형식으로 포함됩니다. 첫 번째 숫자가 0이거나, 3개의 8진수가 있으면, 8진수 이스케이프로 간주합니다. 그렇지 않으면, 그룹 참조입니다. 문자열 리터럴과 마찬가지로, 8진수 이스케이프 길이는 항상 최대 3자리입니다.

버전 3.3에서 변경: '\u'와 '\U' 이스케이프 시퀀스가 추가되었습니다.

버전 3.6에서 변경: '\'와 ASCII 글자로 구성된 알 수 없는 이스케이프는 이제 에러입니다.

버전 3.8에서 변경: The '\N{name}' escape sequence has been added. As in string literals, it expands to the named Unicode character (e.g. '\N{EM DASH}').

모듈 내용

모듈은 몇 가지 함수, 상수 및 예외를 정의합니다. 함수 중 일부는 컴파일된 정규식의 모든 기능을 갖춘 메서드의 단순화된 버전입니다. 대부분의 사소하지 않은 응용 프로그램은 항상 컴파일된 형식을 사용합니다.

Flags

버전 3.6에서 변경: 플래그 상수는 이제 enum.IntFlag의 서브 클래스인 RegexFlag의 인스턴스입니다.

class re.RegexFlag

An enum.IntFlag class containing the regex options listed below.

Added in version 3.11: - added to __all__

re.A

re.ASCII

Make \w, \W, \b, \B, \d, \D, \s and \S perform ASCII-only matching instead of full Unicode matching. This is only meaningful for Unicode (str) patterns, and is ignored for bytes patterns.

Corresponds to the inline flag (?a).

참고

The U flag still exists for backward compatibility, but is redundant in Python 3 since matches are Unicode by default for str patterns, and Unicode matching isn’t allowed for bytes patterns. UNICODE and the inline flag (?u) are similarly redundant.

re.DEBUG

Display debug information about compiled expression.

No corresponding inline flag.

re.I

re.IGNORECASE

Perform case-insensitive matching; expressions like [A-Z] will also match lowercase letters. Full Unicode matching (such as Ü matching ü) also works unless the ASCII flag is used to disable non-ASCII matches. The current locale does not change the effect of this flag unless the LOCALE flag is also used.

Corresponds to the inline flag (?i).

Note that when the Unicode patterns [a-z] or [A-Z] are used in combination with the IGNORECASE flag, they will match the 52 ASCII letters and 4 additional non-ASCII letters: ‘İ’ (U+0130, Latin capital letter I with dot above), ‘ı’ (U+0131, Latin small letter dotless i), ‘ſ’ (U+017F, Latin small letter long s) and ‘K’ (U+212A, Kelvin sign). If the ASCII flag is used, only letters ‘a’ to ‘z’ and ‘A’ to ‘Z’ are matched.

re.L

re.LOCALE

Make \w, \W, \b, \B and case-insensitive matching dependent on the current locale. This flag can be used only with bytes patterns.

Corresponds to the inline flag (?L).

경고

This flag is discouraged; consider Unicode matching instead. The locale mechanism is very unreliable as it only handles one “culture” at a time and only works with 8-bit locales. Unicode matching is enabled by default for Unicode (str) patterns and it is able to handle different locales and languages.

버전 3.6에서 변경: LOCALE can be used only with bytes patterns and is not compatible with ASCII.

버전 3.7에서 변경: Compiled regular expression objects with the LOCALE flag no longer depend on the locale at compile time. Only the locale at matching time affects the result of matching.

re.M

re.MULTILINE

When specified, the pattern character '^' matches at the beginning of the string and at the beginning of each line (immediately following each newline); and the pattern character '$' matches at the end of the string and at the end of each line (immediately preceding each newline). By default, '^' matches only at the beginning of the string, and '$' only at the end of the string and immediately before the newline (if any) at the end of the string.

Corresponds to the inline flag (?m).

re.NOFLAG

Indicates no flag being applied, the value is 0. This flag may be used as a default value for a function keyword argument or as a base value that will be conditionally ORed with other flags. Example of use as a default value:

def myfunc(text, flag=re.NOFLAG):
    return re.match(text, flag)

Added in version 3.11.

re.S

re.DOTALL

Make the '.' special character match any character at all, including a newline; without this flag, '.' will match anything except a newline.

Corresponds to the inline flag (?s).

re.U

re.UNICODE

In Python 3, Unicode characters are matched by default for str patterns. This flag is therefore redundant with no effect and is only kept for backward compatibility.

See ASCII to restrict matching to ASCII characters instead.

re.X

re.VERBOSE

This flag allows you to write regular expressions that look nicer and are more readable by allowing you to visually separate logical sections of the pattern and add comments. Whitespace within the pattern is ignored, except when in a character class, or when preceded by an unescaped backslash, or within tokens like *?, (?: or (?P<...>. For example, (? : and * ? are not allowed. When a line contains a # that is not in a character class and is not preceded by an unescaped backslash, all characters from the leftmost such # through the end of the line are ignored.

이것은 십진수와 일치하는 다음 두 정규식 객체는 기능적으로 같음을 뜻합니다:

a = re.compile(r"""\d +  # the integral part
                   \.    # the decimal point
                   \d *  # some fractional digits""", re.X)
b = re.compile(r"\d+\.\d*")

인라인 플래그 (?x) 에 해당합니다.

Functions

re.compile(pattern, flags=0)

정규식 패턴을 정규식 객체로 컴파일합니다. 정규식 객체는 아래에 설명되는 match(), search() 및 기타 메서드를 일치시키는 데 사용할 수 있습니다.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

시퀀스

prog = re.compile(pattern)
result = prog.match(string)

는 다음과 동등합니다

result = re.match(pattern, string)

하지만 정규식이 단일 프로그램에서 여러 번 사용될 때, re.compile()을 사용하고 결과 정규식 객체를 저장하여 재사용하는 것이 더 효율적입니다.

참고

re.compile()과 모듈 수준 일치 함수에 전달된 가장 최근 패턴의 컴파일된 버전이 캐시 되므로, 한 번에 몇 가지 정규식만 사용하는 프로그램은 정규식 컴파일에 대해 신경 쓸 필요가 없습니다.

re.search(pattern, string, flags=0)

Scan through string looking for the first location where the regular expression pattern produces a match, and return a corresponding Match. Return None if no position in the string matches the pattern; note that this is different from finding a zero-length match at some point in the string.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

re.match(pattern, string, flags=0)

If zero or more characters at the beginning of string match the regular expression pattern, return a corresponding Match. Return None if the string does not match the pattern; note that this is different from a zero-length match.

MULTILINE 모드에서도, re.match()는 각 줄의 시작 부분이 아니라 문자열의 시작 부분에서만 일치함에 유의하십시오.

string의 모든 위치에서 일치를 찾으려면, 대신 search()를 사용하십시오 (search() 대 match()도 참조하십시오).

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

re.fullmatch(pattern, string, flags=0)

If the whole string matches the regular expression pattern, return a corresponding Match. Return None if the string does not match the pattern; note that this is different from a zero-length match.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

Added in version 3.4.

re.split(pattern, string, maxsplit=0, flags=0)

string을 pattern으로 나눕니다. pattern에서 포착하는 괄호가 사용되면 패턴의 모든 그룹 텍스트도 결과 리스트의 일부로 반환됩니다. maxsplit이 0이 아니면, 최대 maxsplit 분할이 발생하고, 나머지 문자열이 리스트의 마지막 요소로 반환됩니다.

>>> re.split(r'\W+', 'Words, words, words.')
['Words', 'words', 'words', '']
>>> re.split(r'(\W+)', 'Words, words, words.')
['Words', ', ', 'words', ', ', 'words', '.', '']
>>> re.split(r'\W+', 'Words, words, words.', maxsplit=1)
['Words', 'words, words.']
>>> re.split('[a-f]+', '0a3B9', flags=re.IGNORECASE)
['0', '3', '9']

구분자에 포착하는 그룹이 있고 문자열 시작 부분에서 일치하면, 결과는 빈 문자열로 시작됩니다. 문자열의 끝에 대해서도 마찬가지입니다:

>>> re.split(r'(\W+)', '...words, words...')
['', '...', 'words', ', ', 'words', '...', '']

그런 식으로, 구분자 구성 요소는 항상 결과 리스트 내의 같은 상대 인덱스에서 발견됩니다.

패턴에 대한 빈(empty) 일치는 이전의 빈 일치와 인접하지 않을 때만 문자열을 분할합니다.

>>> re.split(r'\b', 'Words, words, words.')
['', 'Words', ', ', 'words', ', ', 'words', '.']
>>> re.split(r'\W*', '...words...')
['', '', 'w', 'o', 'r', 'd', 's', '', '']
>>> re.split(r'(\W*)', '...words...')
['', '...', '', '', 'w', '', 'o', '', 'r', '', 'd', '', 's', '...', '', '', '']

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

버전 3.1에서 변경: 선택적 flags 인자를 추가했습니다.

버전 3.7에서 변경: 빈 문자열과 일치 할 수 있는 패턴으로 분할하는 지원을 추가했습니다.

버전 3.13부터 폐지됨: Passing maxsplit and flags as positional arguments is deprecated. In future Python versions they will be keyword-only parameters.

re.findall(pattern, string, flags=0)

Return all non-overlapping matches of pattern in string, as a list of strings or tuples. The string is scanned left-to-right, and matches are returned in the order found. Empty matches are included in the result.

The result depends on the number of capturing groups in the pattern. If there are no groups, return a list of strings matching the whole pattern. If there is exactly one group, return a list of strings matching that group. If multiple groups are present, return a list of tuples of strings matching the groups. Non-capturing groups do not affect the form of the result.

>>> re.findall(r'\bf[a-z]*', 'which foot or hand fell fastest')
['foot', 'fell', 'fastest']
>>> re.findall(r'(\w+)=(\d+)', 'set width=20 and height=10')
[('width', '20'), ('height', '10')]

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

버전 3.7에서 변경: 비어 있지 않은 일치는 이제 이전의 비어 있는 일치 직후에 시작할 수 있습니다.

re.finditer(pattern, string, flags=0)

Return an iterator yielding Match objects over all non-overlapping matches for the RE pattern in string. The string is scanned left-to-right, and matches are returned in the order found. Empty matches are included in the result.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

버전 3.7에서 변경: 비어 있지 않은 일치는 이제 이전의 비어 있는 일치 직후에 시작할 수 있습니다.

re.sub(pattern, repl, string, count=0, flags=0)

string에서 겹치지 않는 pattern의 가장 왼쪽 일치를 repl로 치환하여 얻은 문자열을 반환합니다. 패턴을 찾지 못하면, string이 변경되지 않고 반환됩니다. repl은 문자열이나 함수가 될 수 있습니다; 문자열이면 모든 역 슬래시 이스케이프가 처리됩니다. 즉, \n은 단일 개행 문자로 변환되고, \r는 캐리지 리턴으로 변환되고, 등등. 알 수 없는 ASCII 글자 이스케이프는 나중에 사용하기 위해 예약되어 있으며 에러로 처리됩니다. \&와 같은 다른 알려지지 않은 이스케이프는 그대로 있습니다. \6과 같은 역참조는 패턴에서 그룹 6과 일치하는 부분 문자열로 치환됩니다. 예를 들면:

>>> re.sub(r'def\s+([a-zA-Z_][a-zA-Z_0-9]*)\s*\(\s*\):',
...        r'static PyObject*\npy_\1(void)\n{',
...        'def myfunc():')
'static PyObject*\npy_myfunc(void)\n{'

If repl is a function, it is called for every non-overlapping occurrence of pattern. The function takes a single Match argument, and returns the replacement string. For example:

>>> def dashrepl(matchobj):
...     if matchobj.group(0) == '-': return ' '
...     else: return '-'
...
>>> re.sub('-{1,2}', dashrepl, 'pro----gram-files')
'pro--gram files'
>>> re.sub(r'\sAND\s', ' & ', 'Baked Beans And Spam', flags=re.IGNORECASE)
'Baked Beans & Spam'

The pattern may be a string or a Pattern.

선택적 인자 count는 치환될 패턴 발생의 최대 수입니다; count는 음수가 아닌 정수여야 합니다. 생략되거나 0이면, 모든 발생이 치환됩니다. 패턴에 대한 빈 일치는 이전의 빈 일치와 인접하지 않을 때만 치환되므로, sub('x*', '-', 'abxd')는 '-a-b--d-'를 반환합니다.

문자열형 repl 인자에서, 위에 설명된 문자 이스케이프와 역참조 외에, \g<name>는 (?P<name>...) 문법으로 정의한 name이라는 그룹에 일치하는 부분 문자열을 사용합니다. \g<number>는 해당 그룹 번호를 사용합니다; 따라서 \g<2>는 \2와 동등하지만, \g<2>0와 같은 치환에서 모호하지 않습니다. \20은 그룹 2에 대한 참조에 리터럴 문자 '0'이 뒤에 오는 것이 아니라, 그룹 20에 대한 참조로 해석됩니다. 역참조 \g<0>은 RE와 일치하는 전체 부분 문자열을 치환합니다.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

버전 3.1에서 변경: 선택적 flags 인자를 추가했습니다.

버전 3.5에서 변경: 일치하지 않는 그룹은 빈 문자열로 치환됩니다.

버전 3.6에서 변경: pattern의 '\'와 ASCII 글자(letter)로 구성된 알 수 없는 이스케이프는 이제 에러입니다.

버전 3.7에서 변경: Unknown escapes in repl consisting of '\' and an ASCII letter now are errors. Empty matches for the pattern are replaced when adjacent to a previous non-empty match.

버전 3.12에서 변경: Group id can only contain ASCII digits. In bytes replacement strings, group name can only contain bytes in the ASCII range (b'\x00'-b'\x7f').

버전 3.13부터 폐지됨: Passing count and flags as positional arguments is deprecated. In future Python versions they will be keyword-only parameters.

re.subn(pattern, repl, string, count=0, flags=0)

sub()와 같은 연산을 수행하지만, 튜플 (new_string, number_of_subs_made)를 반환합니다.

The expression’s behaviour can be modified by specifying a flags value. Values can be any of the flags variables, combined using bitwise OR (the | operator).

re.escape(pattern)

pattern에서 특수 문자를 이스케이프 처리합니다. 이것은 정규식 메타 문자가 포함되어있을 수 있는 임의의 리터럴 문자열을 일치시키려는 경우에 유용합니다. 예를 들면:

>>> print(re.escape('https://www.python.org'))
https://www\.python\.org

>>> legal_chars = string.ascii_lowercase + string.digits + "!#$%&'*+-.^_`|~:"
>>> print('[%s]+' % re.escape(legal_chars))
[abcdefghijklmnopqrstuvwxyz0123456789!\#\$%\&'\*\+\-\.\^_`\|\~:]+

>>> operators = ['+', '-', '*', '/', '**']
>>> print('|'.join(map(re.escape, sorted(operators, reverse=True))))
/|\-|\+|\*\*|\*

이 함수는 sub()와 subn()의 치환 문자열에 사용하면 안 되며, 역 슬래시만 이스케이프 해야 합니다. 예를 들면:

>>> digits_re = r'\d+'
>>> sample = '/usr/sbin/sendmail - 0 errors, 12 warnings'
>>> print(re.sub(digits_re, digits_re.replace('\\', r'\\'), sample))
/usr/sbin/sendmail - \d+ errors, \d+ warnings

버전 3.3에서 변경: '_' 문자는 더는 이스케이프 되지 않습니다.

버전 3.7에서 변경: 정규식에서 특별한 의미를 가질 수 있는 문자만 이스케이프 됩니다. 결과적으로, '!', '"', '%', "'", ',', '/', ':', ';', '<', '=', '>', '@' 및 ‘”'는 더는 이스케이프 되지 않습니다.

re.purge()

정규식 캐시를 지웁니다.

Exceptions

exception re.PatternError(msg, pattern=None, pos=None)

Exception raised when a string passed to one of the functions here is not a valid regular expression (for example, it might contain unmatched parentheses) or when some other error occurs during compilation or matching. It is never an error if a string contains no match for a pattern. The PatternError instance has the following additional attributes:

msg

포맷되지 않은 에러 메시지.

pattern

정규식 패턴.

pos

컴파일이 실패한 위치를 가리키는 pattern의 인덱스 (None일 수 있습니다).

lineno

pos에 해당하는 줄 (None일 수 있습니다).

colno

pos에 해당하는 열 (None일 수 있습니다).

버전 3.5에서 변경: 추가 어트리뷰트가 추가되었습니다.

버전 3.13에서 변경: PatternError was originally named error; the latter is kept as an alias for backward compatibility.

정규식 객체

class re.Pattern

Compiled regular expression object returned by re.compile().

버전 3.9에서 변경: re.Pattern supports [] to indicate a Unicode (str) or bytes pattern. See 제네릭 에일리어스 형.

Pattern.search(string[, pos[, endpos]])

Scan through string looking for the first location where this regular expression produces a match, and return a corresponding Match. Return None if no position in the string matches the pattern; note that this is different from finding a zero-length match at some point in the string.

선택적 두 번째 매개 변수 pos는 검색을 시작할 문자열의 인덱스를 제공합니다; 기본값은 0입니다. 이것은 문자열을 슬라이싱하는 것과 완전히 동등하지는 않습니다; '^' 패턴 문자는 문자열의 실제 시작 부분과 개행 직후의 위치에서 일치하지만, 검색을 시작할 색인에서 반드시 일치하지는 않습니다.

선택적 매개 변수 endpos는 문자열을 어디까지 검색할지를 제한합니다; 문자열이 endpos 문자 길이인 것처럼 취급되어, 일치를 찾기 위해 pos에서 endpos - 1까지의 문자만 검색됩니다. endpos가 pos보다 작으면 일치는 없습니다; 그렇지 않으면, rx가 컴파일된 정규식 객체일 때, rx.search(string, 0, 50)는 rx.search(string[:50], 0)와 동등합니다.

>>> pattern = re.compile("d")
>>> pattern.search("dog")     # Match at index 0
<re.Match object; span=(0, 1), match='d'>
>>> pattern.search("dog", 1)  # No match; search doesn't include the "d"

Pattern.match(string[, pos[, endpos]])

If zero or more characters at the beginning of string match this regular expression, return a corresponding Match. Return None if the string does not match the pattern; note that this is different from a zero-length match.

선택적 pos와 endpos 매개 변수는 search() 메서드에서와 같은 의미입니다.

>>> pattern = re.compile("o")
>>> pattern.match("dog")      # No match as "o" is not at the start of "dog".
>>> pattern.match("dog", 1)   # Match as "o" is the 2nd character of "dog".
<re.Match object; span=(1, 2), match='o'>

string의 임의 위치에서 일치를 찾으려면, 대신 search()를 사용하십시오 (search() 대 match()도 참조하십시오).

Pattern.fullmatch(string[, pos[, endpos]])

If the whole string matches this regular expression, return a corresponding Match. Return None if the string does not match the pattern; note that this is different from a zero-length match.

선택적 pos와 endpos 매개 변수는 search() 메서드에서와 같은 의미입니다.

>>> pattern = re.compile("o[gh]")
>>> pattern.fullmatch("dog")      # No match as "o" is not at the start of "dog".
>>> pattern.fullmatch("ogre")     # No match as not the full string matches.
>>> pattern.fullmatch("doggie", 1, 3)   # Matches within given limits.
<re.Match object; span=(1, 3), match='og'>

Added in version 3.4.

Pattern.split(string, maxsplit=0)

split() 함수와 같은데, 컴파일된 패턴을 사용합니다.

Pattern.findall(string[, pos[, endpos]])

findall() 함수와 유사한데, 컴파일된 패턴을 사용합니다. 하지만, search()처럼 검색 영역을 제한하는 선택적 pos와 endpos 매개 변수도 받아들입니다.

Pattern.finditer(string[, pos[, endpos]])

finditer() 함수와 유사한데, 컴파일된 패턴을 사용합니다. 하지만, search()처럼 검색 영역을 제한하는 선택적 pos와 endpos 매개 변수도 받아들입니다.

Pattern.sub(repl, string, count=0)

sub() 함수와 같은데, 컴파일된 패턴을 사용합니다.

Pattern.subn(repl, string, count=0)

subn() 함수와 같은데, 컴파일된 패턴을 사용합니다.

Pattern.flags

The regex matching flags. This is a combination of the flags given to compile(), any (?...) inline flags in the pattern, and implicit flags such as UNICODE if the pattern is a Unicode string.

Pattern.groups

패턴에 있는 포착 그룹 수.

Pattern.groupindex

(?P<id>)로 정의된 기호 그룹 이름을 그룹 번호에 매핑하는 딕셔너리. 패턴에 기호 그룹이 사용되지 않으면 딕셔너리는 비어 있습니다.

Pattern.pattern

패턴 객체가 컴파일된 패턴 문자열.

버전 3.7에서 변경: copy.copy()와 copy.deepcopy() 지원이 추가되었습니다. 컴파일된 정규식 객체는 원자적이라고 간주합니다.

일치 객체

일치 객체는 항상 불리언 값 True를 가집니다. match()와 search()는 일치가 없을 때 None을 반환하기 때문에, 간단한 if 문으로 일치가 있는지 검사할 수 있습니다:

match = re.search(pattern, string)
if match:
    process(match)

class re.Match

Match object returned by successful matches and searches.

버전 3.9에서 변경: re.Match supports [] to indicate a Unicode (str) or bytes match. See 제네릭 에일리어스 형.

Match.expand(template)

Return the string obtained by doing backslash substitution on the template string template, as done by the sub() method. Escapes such as \n are converted to the appropriate characters, and numeric backreferences (\1, \2) and named backreferences (\g<1>, \g<name>) are replaced by the contents of the corresponding group. The backreference \g<0> will be replaced by the entire match.

버전 3.5에서 변경: 일치하지 않는 그룹은 빈 문자열로 치환됩니다.

Match.group([group1, ...])

일치의 하나 이상의 서브 그룹을 반환합니다. 단일 인자가 있으면, 결과는 단일 문자열입니다; 인자가 여러 개면, 결과는 인자당 하나의 항목이 있는 튜플입니다. 인자가 없으면, group1의 기본값은 0입니다 (전체 일치가 반환됩니다). groupN 인자가 0이면, 해당 반환 값은 전체 일치 문자열입니다; 경계를 포함하는 범위 [1..99]에 있으면, 해당 괄호로 묶은 그룹과 일치하는 문자열입니다. 그룹 번호가 음수이거나 패턴에 정의된 그룹 수보다 크면, IndexError 예외가 발생합니다. 패턴이 일치하지 않는 부분에 그룹이 포함되어 있으면, 해당 결과는 None입니다. 그룹이 여러 번 일치하는 패턴의 일부에 포함되어 있으면, 마지막 일치가 반환됩니다.

>>> m = re.match(r"(\w+) (\w+)", "Isaac Newton, physicist")
>>> m.group(0)       # The entire match
'Isaac Newton'
>>> m.group(1)       # The first parenthesized subgroup.
'Isaac'
>>> m.group(2)       # The second parenthesized subgroup.
'Newton'
>>> m.group(1, 2)    # Multiple arguments give us a tuple.
('Isaac', 'Newton')

정규식이 (?P<name>...) 문법을 사용하면, groupN 인자는 그룹 이름으로 그룹을 식별하는 문자열일 수도 있습니다. 문자열 인자가 패턴의 그룹 이름으로 사용되지 않으면, IndexError 예외가 발생합니다.

적당히 복잡한 예:

>>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Malcolm Reynolds")
>>> m.group('first_name')
'Malcolm'
>>> m.group('last_name')
'Reynolds'

이름있는 그룹은 인덱스로 참조할 수도 있습니다:

>>> m.group(1)
'Malcolm'
>>> m.group(2)
'Reynolds'

그룹이 여러 번 일치하면, 마지막 일치만 액세스 할 수 있습니다:

>>> m = re.match(r"(..)+", "a1b2c3")  # Matches 3 times.
>>> m.group(1)                        # Returns only the last match.
'c3'

Match.__getitem__(g)

이것은 m.group(g)와 같습니다. 일치에서 개별 그룹에 더 쉽게 액세스 할 수 있게 합니다:

>>> m = re.match(r"(\w+) (\w+)", "Isaac Newton, physicist")
>>> m[0]       # The entire match
'Isaac Newton'
>>> m[1]       # The first parenthesized subgroup.
'Isaac'
>>> m[2]       # The second parenthesized subgroup.
'Newton'

Named groups are supported as well:

>>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Isaac Newton")
>>> m['first_name']
'Isaac'
>>> m['last_name']
'Newton'

Added in version 3.6.

Match.groups(default=None)

1에서 패턴에 있는 그룹의 수까지, 일치의 모든 서브 그룹을 포함하는 튜플을 반환합니다. default 인자는 일치에 참여하지 않은 그룹에 사용됩니다; 기본값은 None입니다.

예를 들면:

>>> m = re.match(r"(\d+)\.(\d+)", "24.1632")
>>> m.groups()
('24', '1632')

우리가 소수점과 그 이후의 모든 것을 선택적으로 만들면, 모든 그룹이 일치에 참여하지 않을 수 있습니다. 이 그룹은 default 인자가 주어지지 않는 한 기본값 None이 됩니다:

>>> m = re.match(r"(\d+)\.?(\d+)?", "24")
>>> m.groups()      # Second group defaults to None.
('24', None)
>>> m.groups('0')   # Now, the second group defaults to '0'.
('24', '0')

Match.groupdict(default=None)

일치의 모든 이름 있는 서브 그룹을 포함하고, 서브 그룹의 이름을 키로 사용하는 딕셔너리를 반환합니다. default 인자는 일치에 참여하지 않은 그룹에 사용됩니다; 기본값은 None입니다. 예를 들면:

>>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Malcolm Reynolds")
>>> m.groupdict()
{'first_name': 'Malcolm', 'last_name': 'Reynolds'}

Match.start([group])

Match.end([group])

group과 일치하는 부분 문자열의 시작과 끝 인덱스를 반환합니다; group의 기본값은 0입니다 (전체 일치 문자열을 뜻합니다). group이 있지만, 일치에 기여하지 않으면, -1을 반환합니다. 일치 객체 m과 일치에 기여한 그룹 g에서, 그룹 g와 일치하는 부분 문자열(m.group(g)와 동등합니다)은 다음과 같습니다

m.string[m.start(g):m.end(g)]

group이 널 문자열과 일치하면 m.start(group)은 m.end(group)와 같음에 유의하십시오. 예를 들어, m = re.search('b(c?)', 'cba') 이후에, m.start(0)은 1이고, m.end(0)은 2이며, m.start(1)과 m.end(1)은 모두 2이고, m.start(2)는 IndexError 예외를 발생시킵니다.

전자 메일 주소에서 remove_this를 제거하는 예:

>>> email = "tony@tiremove_thisger.net"
>>> m = re.search("remove_this", email)
>>> email[:m.start()] + email[m.end():]
'tony@tiger.net'

Match.span([group])

일치가 m일 때, 2-튜플 (m.start(group), m.end(group))를 반환합니다. group이 일치에 기여하지 않으면, 이것은 (-1, -1)임에 유의하십시오. group의 기본값은 0으로, 전체 일치입니다.

Match.pos

정규식 객체의 search()나 match() 메서드에 전달된 pos 값. 이것은 RE 엔진이 일치를 찾기 시작한 string에 대한 인덱스입니다.

Match.endpos

정규식 객체의 search()나 match() 메서드에 전달된 endpos 값. 이것은 RE 엔진이 넘어가지 않을 string에 대한 인덱스입니다.

Match.lastindex

마지막으로 일치하는 포착 그룹의 정수 인덱스, 또는 그룹이 전혀 일치하지 않으면 None. 예를 들어, 정규식 (a)b, ((a)(b)) 및 ((ab))는 문자열 'ab'에 적용될 경우 lastindex == 1이 되지만, (a)(b) 정규식은 같은 문자열에 적용될 때 lastindex == 2가 됩니다.

Match.lastgroup

마지막으로 일치하는 포착 그룹의 이름, 또는 그룹에 이름이 없거나, 그룹이 전혀 일치하지 않으면 None.

Match.re

match()나 search() 메서드가 이 일치 인스턴스를 생성한 정규식 객체.

Match.string

match()나 search()에 전달된 문자열.

버전 3.7에서 변경: copy.copy()와 copy.deepcopy() 지원이 추가되었습니다. 일치 객체는 원자적이라고 간주합니다.

정규식 예제

쌍 검사하기

이 예제에서는, 다음과 같은 도우미 함수를 사용하여 좀 더 세련되게 일치 객체를 표시합니다:

def displaymatch(match):
    if match is None:
        return None
    return '<Match: %r, groups=%r>' % (match.group(), match.groups())

플레이어의 패를 5문자 문자열로 나타내는 포커 프로그램을 작성하고 있다고 가정해봅시다. “a”는 에이스, “k”는 킹, “q”는 퀸, “j”는 잭, “t”는 10, “2”에서 “9”는 그 값의 카드를 나타냅니다.

주어진 문자열이 유효한 패인지 보려면, 다음과 같이 할 수 있습니다:

>>> valid = re.compile(r"^[a2-9tjqk]{5}$")
>>> displaymatch(valid.match("akt5q"))  # Valid.
"<Match: 'akt5q', groups=()>"
>>> displaymatch(valid.match("akt5e"))  # Invalid.
>>> displaymatch(valid.match("akt"))    # Invalid.
>>> displaymatch(valid.match("727ak"))  # Valid.
"<Match: '727ak', groups=()>"

마지막 패 "727ak"는 페어, 즉 같은 값의 카드 두 장을 포함합니다. 이것을 정규식과 일치시키려면, 역참조를 다음과 같이 사용할 수 있습니다:

>>> pair = re.compile(r".*(.).*\1")
>>> displaymatch(pair.match("717ak"))     # Pair of 7s.
"<Match: '717', groups=('7',)>"
>>> displaymatch(pair.match("718ak"))     # No pairs.
>>> displaymatch(pair.match("354aa"))     # Pair of aces.
"<Match: '354aa', groups=('a',)>"

페어가 어떤 카드로 구성되어 있는지 알아내려면, 다음과 같이 일치 객체의 group() 메서드를 사용할 수 있습니다:

>>> pair = re.compile(r".*(.).*\1")
>>> pair.match("717ak").group(1)
'7'

# Error because re.match() returns None, which doesn't have a group() method:
>>> pair.match("718ak").group(1)
Traceback (most recent call last):
  File "<pyshell#23>", line 1, in <module>
    re.match(r".*(.).*\1", "718ak").group(1)
AttributeError: 'NoneType' object has no attribute 'group'

>>> pair.match("354aa").group(1)
'a'

scanf() 시뮬레이션

Python does not currently have an equivalent to scanf(). Regular expressions are generally more powerful, though also more verbose, than scanf() format strings. The table below offers some more-or-less equivalent mappings between scanf() format tokens and regular expressions.

scanf() Token

정규식

%c

.

%5c

.{5}

%d

[-+]?\d+

%e, %E, %f, %g

[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?

%i

[-+]?(0[xX][\dA-Fa-f]+|0[0-7]*|\d+)

%o

[-+]?[0-7]+

%s

\S+

%u

\d+

%x, %X

[-+]?(0[xX])?[\dA-Fa-f]+

다음과 같은 문자열에서 파일명과 숫자를 추출하려면

/usr/sbin/sendmail - 0 errors, 4 warnings

you would use a scanf() format like

%s - %d errors, %d warnings

동등한 정규식은 다음과 같습니다

(\S+) - (\d+) errors, (\d+) warnings

search() 대 match()

Python offers different primitive operations based on regular expressions:

re.match() checks for a match only at the beginning of the string

re.search() checks for a match anywhere in the string (this is what Perl does by default)

re.fullmatch() checks for entire string to be a match

예를 들면:

>>> re.match("c", "abcdef")    # No match
>>> re.search("c", "abcdef")   # Match
<re.Match object; span=(2, 3), match='c'>
>>> re.fullmatch("p.*n", "python") # Match
<re.Match object; span=(0, 6), match='python'>
>>> re.fullmatch("r.*n", "python") # No match

'^'로 시작하는 정규식은 search()와 함께 사용하여 문자열 시작 부분의 일치로 제한 할 수 있습니다:

>>> re.match("c", "abcdef")    # No match
>>> re.search("^c", "abcdef")  # No match
>>> re.search("^a", "abcdef")  # Match
<re.Match object; span=(0, 1), match='a'>

그러나 MULTILINE 모드에서 match()는 문자열 시작 부분에서만 일치하지만, '^'로 시작하는 정규식을 search()에 사용하면 각 줄의 시작 부분에서 일치합니다.

>>> re.match("X", "A\nB\nX", re.MULTILINE)  # No match
>>> re.search("^X", "A\nB\nX", re.MULTILINE)  # Match
<re.Match object; span=(4, 5), match='X'>

전화번호부 만들기

split()는 문자열을, 전달된 패턴으로 구분된 리스트로 분할합니다. 이 메서드는 전화번호부를 만드는 다음 예제에서 보이듯이 텍스트 데이터를 파이썬에서 쉽게 읽고 수정할 수 있는 데이터 구조로 변환하는 데 매우 중요합니다.

먼저, 여기 입력이 있습니다. 보통 파일에서 올 수 있습니다만, 여기서는 삼중 따옴표로 묶인 문자열 문법을 사용합니다.

>>> text = """Ross McFluff: 834.345.1254 155 Elm Street
...
... Ronald Heathmore: 892.345.3428 436 Finley Avenue
... Frank Burger: 925.541.7625 662 South Dogwood Way
...
...
... Heather Albrecht: 548.326.4584 919 Park Place"""

항목은 하나 이상의 개행으로 구분됩니다. 이제 비어있지 않은 각 줄이 항목이 되도록 문자열을 리스트로 변환합니다:

>>> entries = re.split("\n+", text)
>>> entries
['Ross McFluff: 834.345.1254 155 Elm Street',
'Ronald Heathmore: 892.345.3428 436 Finley Avenue',
'Frank Burger: 925.541.7625 662 South Dogwood Way',
'Heather Albrecht: 548.326.4584 919 Park Place']

마지막으로, 각 항목을 이름, 성, 전화번호 및 주소로 구성된 리스트로 분할합니다. 주소에 우리의 분할 패턴인 스페이스가 들어있기 때문에, split()의 maxsplit 매개 변수를 사용합니다:

>>> [re.split(":? ", entry, maxsplit=3) for entry in entries]
[['Ross', 'McFluff', '834.345.1254', '155 Elm Street'],
['Ronald', 'Heathmore', '892.345.3428', '436 Finley Avenue'],
['Frank', 'Burger', '925.541.7625', '662 South Dogwood Way'],
['Heather', 'Albrecht', '548.326.4584', '919 Park Place']]

:? 패턴은 결과 리스트에 나타나지 않도록, 성 뒤의 콜론과 일치합니다. maxsplit로 4를 사용하면, 번지수를 거리 이름과 분리 할 수 있습니다:

>>> [re.split(":? ", entry, maxsplit=4) for entry in entries]
[['Ross', 'McFluff', '834.345.1254', '155', 'Elm Street'],
['Ronald', 'Heathmore', '892.345.3428', '436', 'Finley Avenue'],
['Frank', 'Burger', '925.541.7625', '662', 'South Dogwood Way'],
['Heather', 'Albrecht', '548.326.4584', '919', 'Park Place']]

텍스트 뒤섞기

sub()는 패턴의 모든 일치를 문자열이나 함수의 결과로 치환합니다. 이 예제는 sub()에 텍스트를 “뒤섞는”, 즉 문장의 각 단어에서 첫 번째 문자와 마지막 문자를 제외한 모든 문자의 순서를 무작위로 바꾸는 함수를 사용하는 방법을 보여줍니다:

>>> def repl(m):
...     inner_word = list(m.group(2))
...     random.shuffle(inner_word)
...     return m.group(1) + "".join(inner_word) + m.group(3)
...
>>> text = "Professor Abdolmalek, please report your absences promptly."
>>> re.sub(r"(\w)(\w+)(\w)", repl, text)
'Poefsrosr Aealmlobdk, pslaee reorpt your abnseces plmrptoy.'
>>> re.sub(r"(\w)(\w+)(\w)", repl, text)
'Pofsroser Aodlambelk, plasee reoprt yuor asnebces potlmrpy.'

모든 부사 찾기

findall()은 search()처럼 첫 번째 등장뿐만 아니라, 패턴의 모든 등장과 일치합니다. 예를 들어, 작가가 어떤 텍스트에서 부사를 모두 찾고 싶으면, 다음과 같은 방식으로 findall()을 사용할 수 있습니다:

>>> text = "He was carefully disguised but captured quickly by police."
>>> re.findall(r"\w+ly\b", text)
['carefully', 'quickly']

모든 부사와 그 위치 찾기

If one wants more information about all matches of a pattern than the matched text, finditer() is useful as it provides Match objects instead of strings. Continuing with the previous example, if a writer wanted to find all of the adverbs and their positions in some text, they would use finditer() in the following manner:

>>> text = "He was carefully disguised but captured quickly by police."
>>> for m in re.finditer(r"\w+ly\b", text):
...     print('%02d-%02d: %s' % (m.start(), m.end(), m.group(0)))
07-16: carefully
40-47: quickly

날 문자열 표기법

날 문자열 표기법(r"text")은 정규식을 합리적인 상태로 유지합니다. 이것 없이는, 정규식의 모든 역 슬래시('\')를 이스케이프 하기 위해 그 앞에 또 하나의 역 슬래시를 붙여야 합니다. 예를 들어, 다음 두 코드 줄은 기능상으로 같습니다:

>>> re.match(r"\W(.)\1\W", " ff ")
<re.Match object; span=(0, 4), match=' ff '>
>>> re.match("\\W(.)\\1\\W", " ff ")
<re.Match object; span=(0, 4), match=' ff '>

리터럴 역 슬래시와 일치시키려면, 정규식에서 이스케이프 되어야 합니다. 날 문자열 표기법을 사용하면, r"\\"이 됩니다. 날 문자열 표기법을 사용하지 않으면, "\\\\"를 사용해야 하는데, 다음 코드 줄들은 기능적으로 같습니다:

>>> re.match(r"\\", r"\\")
<re.Match object; span=(0, 1), match='\\'>
>>> re.match("\\\\", r"\\")
<re.Match object; span=(0, 1), match='\\'>

토크나이저 작성하기

토크나이저나 스캐너 [https://en.wikipedia.org/wiki/Lexical_analysis]는 문자열을 분석하여 문자 그룹을 분류합니다. 이것은 컴파일러나 인터프리터를 작성하는 데 유용한 첫 번째 단계입니다.

텍스트 범주는 정규식으로 지정됩니다. 이 기법은 이들을 하나의 마스터 정규식으로 결합하고 연속적인 일치를 반복하는 것입니다:

from typing import NamedTuple
import re

class Token(NamedTuple):
    type: str
    value: str
    line: int
    column: int

def tokenize(code):
    keywords = {'IF', 'THEN', 'ENDIF', 'FOR', 'NEXT', 'GOSUB', 'RETURN'}
    token_specification = [
        ('NUMBER',   r'\d+(\.\d*)?'),  # Integer or decimal number
        ('ASSIGN',   r':='),           # Assignment operator
        ('END',      r';'),            # Statement terminator
        ('ID',       r'[A-Za-z]+'),    # Identifiers
        ('OP',       r'[+\-*/]'),      # Arithmetic operators
        ('NEWLINE',  r'\n'),           # Line endings
        ('SKIP',     r'[ \t]+'),       # Skip over spaces and tabs
        ('MISMATCH', r'.'),            # Any other character
    ]
    tok_regex = '|'.join('(?P<%s>%s)' % pair for pair in token_specification)
    line_num = 1
    line_start = 0
    for mo in re.finditer(tok_regex, code):
        kind = mo.lastgroup
        value = mo.group()
        column = mo.start() - line_start
        if kind == 'NUMBER':
            value = float(value) if '.' in value else int(value)
        elif kind == 'ID' and value in keywords:
            kind = value
        elif kind == 'NEWLINE':
            line_start = mo.end()
            line_num += 1
            continue
        elif kind == 'SKIP':
            continue
        elif kind == 'MISMATCH':
            raise RuntimeError(f'{value!r} unexpected on line {line_num}')
        yield Token(kind, value, line_num, column)

statements = '''
    IF quantity THEN
        total := total + price * quantity;
        tax := price * 0.05;
    ENDIF;
'''

for token in tokenize(statements):
    print(token)

토크나이저는 다음과 같은 출력을 생성합니다:

Token(type='IF', value='IF', line=2, column=4)
Token(type='ID', value='quantity', line=2, column=7)
Token(type='THEN', value='THEN', line=2, column=16)
Token(type='ID', value='total', line=3, column=8)
Token(type='ASSIGN', value=':=', line=3, column=14)
Token(type='ID', value='total', line=3, column=17)
Token(type='OP', value='+', line=3, column=23)
Token(type='ID', value='price', line=3, column=25)
Token(type='OP', value='*', line=3, column=31)
Token(type='ID', value='quantity', line=3, column=33)
Token(type='END', value=';', line=3, column=41)
Token(type='ID', value='tax', line=4, column=8)
Token(type='ASSIGN', value=':=', line=4, column=12)
Token(type='ID', value='price', line=4, column=15)
Token(type='OP', value='*', line=4, column=21)
Token(type='NUMBER', value=0.05, line=4, column=23)
Token(type='END', value=';', line=4, column=27)
Token(type='ENDIF', value='ENDIF', line=5, column=4)
Token(type='END', value=';', line=5, column=9)

[Frie09]

Friedl, Jeffrey. Mastering Regular Expressions. 3rd ed., O’Reilly Media, 2009. 이 책의 세 번째 판은 더는 파이썬을 다루지 않지만, 초판은 훌륭한 정규식 패턴 작성을 아주 자세하게 다루었습니다.

difflib — Helpers for computing deltas

소스 코드: Lib/difflib.py [https://github.com/python/cpython/tree/main/Lib/difflib.py]

이 모듈은 시퀀스 비교를 위한 클래스와 함수를 제공합니다. 예를 들어 파일을 비교하는 데 사용할 수 있으며, HTML 및 문맥(context)과 통합(unified) diff를 비롯한 다양한 형식의 파일 차이에 관한 정보를 생성할 수 있습니다. 디렉터리와 파일을 비교하려면, filecmp 모듈을 참조하십시오.

class difflib.SequenceMatcher

이것은 시퀀스 요소가 해시 가능이기만 하다면, 모든 형의 시퀀스 쌍을 비교할 수 있는 유연한 클래스입니다. 기본 알고리즘은 1980년대 후반에 Ratcliff와 Obershelp가 ‘게슈탈트 패턴 매칭(gestalt pattern matching)’이라는 과장된 이름으로 발표한 알고리즘까지 거슬러 올라가는데, 그보다는 약간 더 공을 들였습니다. 아이디어는 “정크” 요소가 없는 가장 긴 연속적으로 일치하는 서브 시퀀스를 찾는 것입니다; 이러한 “정크” 요소는 빈 줄이나 공백과 같은 어떤 의미에서는 흥미롭지 않은 요소들입니다. (정크 처리는 Ratcliff와 Obershelp 알고리즘의 확장입니다.) 그런 다음 같은 아이디어를 일치하는 서브 시퀀스의 왼쪽과 오른쪽에 있는 시퀀스 조각에 재귀적으로 적용합니다. 이것이 최소 편집 시퀀스를 산출하지는 않지만, 사람들에게 “그럴듯해 보이는” 일치를 산출하는 경향이 있습니다.

타이밍: 기본 Ratcliff-Obershelp 알고리즘은 최악의 상황(worst case)에 세제곱 시간이고, 평균적으로(expected case) 제곱 시간입니다. SequenceMatcher는 최악의 상황에 제곱 시간이며, 평균적인 동작은 시퀀스에 공통으로 포함된 요소의 수에 따라 복잡한 방식으로 달라집니다; 최상의 경우(best cast)는 선형 시간입니다.

자동 정크 휴리스틱: SequenceMatcher는 특정 시퀀스 항목을 자동으로 정크로 처리하는 경험적 방법을 지원합니다. 경험적 방법은 개별 항목이 시퀀스에 나타나는 횟수를 계산합니다. (첫 번째 항목 이후의) 중복된 항목이 시퀀스의 1% 이상을 차지하고 시퀀스의 길이가 최소 200항목 이상이면, 이 항목은 “흔한” 것으로 표시되고 시퀀스 일치를 위해 정크로 처리됩니다. 이 경험적 방법은 SequenceMatcher를 만들 때 autojunk 인자를 False로 설정하여 끌 수 있습니다.

버전 3.2에서 변경: Added the autojunk parameter.

class difflib.Differ

이것은 텍스트 줄의 시퀀스를 비교하고, 사람이 읽을 수 있는 차이 또는 델타를 생성하는 클래스입니다. Differ는 줄의 시퀀스를 비교하고, 유사한 (거의 일치하는) 줄 내의 문자 시퀀스를 비교하는데 SequenceMatcher를 사용합니다.

Differ 델타의 각 줄은 2자 코드로 시작합니다:

코드

뜻

'- '

시퀀스 1에만 있는 줄

'+ '

시퀀스 2에만 있는 줄

'  '

두 시퀀스에 공통인 줄

'? '

두 입력 시퀀스에 없는 줄

Lines beginning with ‘?’ attempt to guide the eye to intraline differences, and were not present in either input sequence. These lines can be confusing if the sequences contain whitespace characters, such as spaces, tabs or line breaks.

class difflib.HtmlDiff

이 클래스는 HTML 표를 (또는 표를 포함하는 완전한 HTML 파일을) 만드는 데 사용할 수 있습니다. 이 HTML은 줄 간과 줄 내의 변경을 강조하면서, 텍스트를 나란히 줄 단위로 비교하여 보여줍니다. 표는 전체 또는 문맥 차이 모드로 생성될 수 있습니다.

이 클래스의 생성자는 다음과 같습니다:

__init__(tabsize=8, wrapcolumn=None, linejunk=None, charjunk=IS_CHARACTER_JUNK)

HtmlDiff의 인스턴스를 초기화합니다.

tabsize는 탭 간격을 지정하는 선택적 키워드 인자이며 기본값은 8입니다.

wrapcolumn는 줄이 자동 줄 넘김 되는 열 번호를 지정하는 선택적 키워드로, 줄을 자동 줄 넘김 하지 않는 None이 기본값입니다.

linejunk 와 charjunk는 ndiff()(HtmlDiff가 나란히 배치된 HTML 차이를 만드는 데 사용됩니다)로 전달되는 선택적 키워드 인자입니다. 인자 기본값과 설명은 ndiff() 설명서를 참조하십시오.

다음과 같은 메서드가 공개됩니다:

make_file(fromlines, tolines, fromdesc='', todesc='', context=False, numlines=5, *, charset='utf-8')

fromlines 와 tolines(문자열의 리스트)를 비교하고, 줄 간 및 줄 내부의 변경을 강조하면서, 줄 단위로 차이를 보여주는 표를 포함하는 완전한 HTML 파일을 문자열로 반환합니다.

fromdesc 와 todesc는 from/to 파일 열 헤더 문자열을 지정하는 선택적 키워드 인자입니다 (기본값은 모두 빈 문자열입니다).

context 와 numlines는 모두 선택적 키워드 인자입니다. 문맥 차이를 표시하려면 context를 True로 설정하십시오, 그렇지 않으면 기본값은 전체 파일을 표시하는 False입니다. numlines의 기본값은 5입니다. context가 True 일 때, numlines는 차이 하이라이트를 둘러싸는 문맥 줄의 수를 제어합니다. context가 False면 numlines는 “next” 하이퍼 링크를 사용할 때 차이 하이라이트 앞에 표시되는 줄 수를 제어합니다 (0으로 설정하면 “next” 하이퍼 링크가 다음 차이 하이라이트를 아무런 선행 문맥 줄 없이 브라우저의 맨 위에 놓도록 합니다).

참고

fromdesc와 todesc는 이스케이프 되지 않은 HTML로 해석되며 신뢰할 수 없는 소스로부터 입력을 받는 동안 적절히 이스케이프 되어야 합니다.

버전 3.5에서 변경: charset 키워드 전용 인자가 추가되었습니다. HTML 문서의 기본 문자 집합이 'ISO-8859-1'에서 'utf-8'로 변경되었습니다.

make_table(fromlines, tolines, fromdesc='', todesc='', context=False, numlines=5)

fromlines 와 tolines(문자열의 리스트)를 비교하고, 줄 간 및 줄 내부의 변경을 강조하면서, 줄 단위로 차이를 보여주는 완전한 HTML 표를 문자열로 반환합니다.

이 메서드의 인자는 make_file() 메서드의 인자와 같습니다.

difflib.context_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\n')

a와 b(문자열의 리스트)를 비교합니다; 델타(델타 줄을 생성하는 제너레이터)를 문맥 diff 형식으로 반환합니다.

문맥 diff는 단지 변경된 줄과 몇 줄의 문맥만을 더해서 표시하는 간결한 방법입니다. 변경 사항은 이전/이후 스타일로 표시됩니다. 문맥 줄의 수는 n에 의해 설정되며 기본값은 3입니다.

기본적으로, diff 제어 줄(***나 ---가 포함된 것)은 끝에 줄 넘김을 붙여 만들어집니다. 이것은 io.IOBase.readlines()로 만들어진 입력이 io.IOBase.writelines()와 함께 사용하기에 적합한 diff를 생성하도록 하는 데 유용합니다. 왜냐하면, 입력과 출력 모두 끝에 줄 넘김이 있기 때문입니다.

끝에 줄 넘김이 없는 입력이면, lineterm 인자를 ""로 설정해서 출력에 일관되게 줄 넘김이 포함되지 않게 하십시오.

문맥 diff 형식에는 일반적으로 파일명과 수정 시간에 대한 헤더가 있습니다. 이들 중 일부 또는 전부는 fromfile, tofile, fromfiledate 및 tofiledate에 문자열을 사용하여 지정될 수 있습니다. 수정 시간은 일반적으로 ISO 8601 형식으로 표현됩니다. 지정하지 않으면, 문자열들의 기본값은 빈 문자열입니다.

>>> import sys
>>> from difflib import *
>>> s1 = ['bacon\n', 'eggs\n', 'ham\n', 'guido\n']
>>> s2 = ['python\n', 'eggy\n', 'hamster\n', 'guido\n']
>>> sys.stdout.writelines(context_diff(s1, s2, fromfile='before.py',
...                        tofile='after.py'))
*** before.py
--- after.py
***************
*** 1,4 ****
! bacon
! eggs
! ham
  guido
--- 1,4 ----
! python
! eggy
! hamster
  guido

더욱 자세한 예제는 difflib의 명령 줄 인터페이스를 참조하십시오.

difflib.get_close_matches(word, possibilities, n=3, cutoff=0.6)

최상의 “충분히 좋은” 일치의 리스트를 반환합니다. word는 근접 일치가 목표로 하는 시퀀스(일반적으로 문자열)며, possibilities는 word와 일치시킬 시퀀스의 리스트입니다 (일반적으로 문자열의 리스트).

선택적 인자 n(기본값 3)은 반환할 근접 일치의 최대 개수입니다; n는 0보다 커야 합니다.

선택적 인자 cutoff(기본값 0.6)는 [0, 1] 범위의 float입니다. word와의 유사성 점수가 이 값보다 적은 possibilities는 무시됩니다.

possibilities 중에서 가장 좋은 (최대 n 개의) 일치가 리스트로 반환되는데, 유사성 점수로 정렬되어 있고 가장 유사한 것이 먼저 나옵니다.

>>> get_close_matches('appel', ['ape', 'apple', 'peach', 'puppy'])
['apple', 'ape']
>>> import keyword
>>> get_close_matches('wheel', keyword.kwlist)
['while']
>>> get_close_matches('pineapple', keyword.kwlist)
[]
>>> get_close_matches('accept', keyword.kwlist)
['except']

difflib.ndiff(a, b, linejunk=None, charjunk=IS_CHARACTER_JUNK)

a와 b(문자열의 리스트)를 비교합니다; Differ-스타일 델타(델타 줄을 생성하는 제너레이터)를 반환합니다.

선택적 키워드 매개 변수 linejunk 와 charjunk는 필터링 함수(또는 None)입니다:

linejunk: 단일 문자열 인자를 받아들이고 문자열이 정크면 참을 반환하고, 그렇지 않으면 거짓을 반환하는 함수입니다. 기본값은 None입니다. 모듈 수준의 함수 IS_LINE_JUNK()도 있는데, 최대로 한 개의 파운드 문자('#')를 제외하고 눈에 보이는 문자가 없는 줄을 걸러냅니다 – 하지만 하부 SequenceMatcher 클래스는 어떤 줄이 잡음으로 볼만큼 자주 등장하는지 동적으로 분석하고, 이것이 보통 이 함수를 사용하는 것보다 효과적입니다.

charjunk: 문자(길이 1의 문자열)를 받아들이고, 문자가 정크면 참을 반환하고, 그렇지 않으면 거짓을 반환하는 함수입니다. 기본값은 모듈 수준의 함수 IS_CHARACTER_JUNK()인데, 공백 문자(스페이스나 탭; 줄 넘김 문자를 포함하는 것은 좋은 생각이 아닙니다)를 걸러냅니다.

>>> diff = ndiff('one\ntwo\nthree\n'.splitlines(keepends=True),
...              'ore\ntree\nemu\n'.splitlines(keepends=True))
>>> print(''.join(diff), end="")
- one
?  ^
+ ore
?  ^
- two
- three
?  -
+ tree
+ emu

difflib.restore(sequence, which)

델타를 만든 두 시퀀스 중 하나를 반환합니다.

Differ.compare() 나 ndiff()로 만들어진 sequence가 주어지면, 파일 1이나 2(매개 변수 which)에서 원래 제공되었던 줄을 추출하고, 줄 접두어를 제거합니다.

예:

>>> diff = ndiff('one\ntwo\nthree\n'.splitlines(keepends=True),
...              'ore\ntree\nemu\n'.splitlines(keepends=True))
>>> diff = list(diff) # materialize the generated delta into a list
>>> print(''.join(restore(diff, 1)), end="")
one
two
three
>>> print(''.join(restore(diff, 2)), end="")
ore
tree
emu

difflib.unified_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\n')

a와 b(문자열의 리스트)를 비교합니다; 델타(델타 줄을 생성하는 제너레이터)를 통합 diff 형식으로 반환합니다.

통합(unified) diff는 단지 변경된 줄과 몇 줄의 문맥만을 더해서 표시하는 간결한 방법입니다. 변경 사항은 (별도의 이전/이후 블록 대신) 인라인 스타일로 표시됩니다. 문맥 줄의 수는 n에 의해 설정되며 기본값은 3입니다.

기본적으로, diff 제어 줄(---, +++ 또는 @@가 포함된 것)은 끝에 줄 넘김을 붙여 만들어집니다. 이것은 io.IOBase.readlines()로 만들어진 입력이 io.IOBase.writelines()와 함께 사용하기에 적합한 diff를 생성하도록 하는 데 유용합니다. 왜냐하면, 입력과 출력 모두 끝에 줄 넘김이 있기 때문입니다.

끝에 줄 넘김이 없는 입력이면, lineterm 인자를 ""로 설정해서 출력에 일관되게 줄 넘김이 포함되지 않게 하십시오.

The unified diff format normally has a header for filenames and modification times. Any or all of these may be specified using strings for fromfile, tofile, fromfiledate, and tofiledate. The modification times are normally expressed in the ISO 8601 format. If not specified, the strings default to blanks.

>>> s1 = ['bacon\n', 'eggs\n', 'ham\n', 'guido\n']
>>> s2 = ['python\n', 'eggy\n', 'hamster\n', 'guido\n']
>>> sys.stdout.writelines(unified_diff(s1, s2, fromfile='before.py', tofile='after.py'))
--- before.py
+++ after.py
@@ -1,4 +1,4 @@
-bacon
-eggs
-ham
+python
+eggy
+hamster
 guido

더욱 자세한 예제는 difflib의 명령 줄 인터페이스를 참조하십시오.

difflib.diff_bytes(dfunc, a, b, fromfile=b'', tofile=b'', fromfiledate=b'', tofiledate=b'', n=3, lineterm=b'\n')

a와 b(바이트열 객체의 리스트)를 dfunc를 사용하여 비교합니다; dfunc가 반환하는 형식으로 델타 줄(역시 바이트열)의 시퀀스를 산출합니다. dfunc는 콜러블이어야하며, 보통 unified_diff() 나 context_diff()입니다.

알 수 없거나 일관성 없는 인코딩의 데이터를 비교할 수 있게 합니다. n를 제외한 모든 입력은 바이트열 객체여야 합니다, str이 아닙니다. 모든 입력(n 제외)을 str로 무손실 변환하고, dfunc(a, b, fromfile, tofile, fromfiledate, tofiledate, n, lineterm)를 호출하는 방식으로 작동합니다. dfunc의 출력은 다시 바이트로 변환되므로, 여러분이 얻는 델타 줄은 a와 b 처럼 알 수 없고/일관성 없는 인코딩을 갖습니다.

Added in version 3.5.

difflib.IS_LINE_JUNK(line)

무시할 수 있는 줄이면 True를 반환합니다. line이 빈 줄이거나 하나의 '#'를 포함하면, 줄 line은 무시할 수 있습니다, 그렇지 않으면 무시할 수 없습니다. 이전 버전의 ndiff()에서 매개 변수 linejunk의 기본값으로 사용되었습니다.

difflib.IS_CHARACTER_JUNK(ch)

무시할 수 있는 문자면 True를 반환합니다. ch가 스페이스나 탭이면 문자 ch는 무시할 수 있습니다, 그렇지 않으면 무시할 수 없습니다. ndiff()에서 매개 변수 charjunk의 기본값으로 사용됩니다.

더 보기

Pattern Matching: The Gestalt Approach [https://www.drdobbs.com/database/pattern-matching-the-gestalt-approach/184407970]

Discussion of a similar algorithm by John W. Ratcliff and D. E. Metzener. This was published in Dr. Dobb’s Journal [https://www.drdobbs.com/] in July, 1988.

SequenceMatcher 객체

SequenceMatcher 클래스는 다음과 같은 생성자를 갖습니다:

class difflib.SequenceMatcher(isjunk=None, a='', b='', autojunk=True)

선택 인자 isjunk는 None(기본값)이거나, 시퀀스 요소를 받아서 요소가 “정크” 이고, 무시되어야 하는 경우에만 참을 반환하는 하나의 인자 함수여야 합니다. isjunk에 None을 전달하는 것은, lambda x: False를 전달하는 것과 같습니다; 즉, 아무 요소도 무시하지 않습니다. 예를 들어,:

lambda x: x in " \t"

줄을 문자의 시퀀스로 비교하고, 스페이스와 탭을 무시하고 싶으면, 위와 같은 것을 전달하면 됩니다.

선택적 인자 a 와 b는 비교할 시퀀스입니다; 둘 다 빈 문자열이 기본값입니다. 두 시퀀스의 요소는 모두 해시 가능해야 합니다.

선택적 인자 autojunk는 자동 정크 휴리스틱을 비활성화하는 데 사용할 수 있습니다.

버전 3.2에서 변경: Added the autojunk parameter.

SequenceMatcher 객체는 세 개의 데이터 어트리뷰트를 갖습니다: bjunk는 isjunk가 True 인 b 요소의 집합입니다; bpopular는 휴리스틱(비활성화하지 않았다면)에서 흔하다고 판단되는 정크가 아닌 요소의 집합입니다; b2j는 b의 나머지 요소를 그들이 나타난 위치의 리스트로 매핑하는 dict입니다. b가 set_seqs() 나 set_seq2()로 재설정 될 때마다 세 개 모두 재설정됩니다.

Added in version 3.2: bjunk 및 bpopular 어트리뷰트

SequenceMatcher 객체에는 다음과 같은 메서드가 있습니다:

set_seqs(a, b)

비교할 두 시퀀스를 설정합니다.

SequenceMatcher는 두 번째 시퀀스에 대한 자세한 정보를 계산하고 캐시 하므로, 많은 시퀀스에 대해 하나의 시퀀스를 비교하려면, set_seq2()를 사용하여 자주 사용되는 시퀀스를 한 번 설정하고, set_seq1()를 다른 시퀀스 각각에 대해 한 번 반복적으로 호출하십시오.

set_seq1(a)

비교할 첫 번째 시퀀스를 설정합니다. 비교할 두 번째 시퀀스는 변경되지 않습니다.

set_seq2(b)

비교할 두 번째 시퀀스를 설정합니다. 비교할 첫 번째 시퀀스는 변경되지 않습니다.

find_longest_match(alo=0, ahi=None, blo=0, bhi=None)

a[alo:ahi] 와 b[blo:bhi]에서 가장 긴 일치 블록을 찾습니다.

isjunk가 생략되거나 None 이면, find_longest_match()는 a[i:i+k]가 b[j:j+k]와 같은 (i, j, k)를 반환하는데, 여기서 alo <= i <= i+k <= ahi 이고 blo <= j <= j+k <= bhi 입니다. 이 조건을 만족시키는 모든 (i', j', k')에 대해, 추가 조건 k >= k', i <= i' 와 i == i' 면 j <= j' 도 만족합니다. 즉, 모든 최대 일치 블록 중에서 a에서 가장 먼저 시작하는 블록을 반환하고, a에서 가장 먼저 시작하는 모든 최대 일치 블록 중에서 b에서 가장 먼저 시작하는 블록을 반환합니다.

>>> s = SequenceMatcher(None, " abcd", "abcd abcd")
>>> s.find_longest_match(0, 5, 0, 9)
Match(a=0, b=4, size=5)

isjunk가 제공되면, 먼저 가장 긴 일치 블록이 상기와 같이 결정되지만, 정크 요소가 블록에 나타나지 않아야 한다는 추가 제약이 있습니다. 그런 다음 그 블록의 좌우에서 정크 요소만 일치시켜 가능한 한 최대로 확장합니다. 그래서 결과 블록은 흥미로운 일치와 인접하게 같은 정크가 등장할 때를 제외하고는, 정크와 일치하지 않습니다.

여기에 이전과 같은 예가 있지만, 스페이스를 정크로 간주합니다. 이렇게 하면 ' abcd'가 두 번째 시퀀스의 끝에 있는 ' abcd'와 직접 일치하지 않게 됩니다. 대신 'abcd' 만 일치 할 수 있으며, 두 번째 시퀀스에서 가장 왼쪽의 'abcd'와 일치합니다:

>>> s = SequenceMatcher(lambda x: x==" ", " abcd", "abcd abcd")
>>> s.find_longest_match(0, 5, 0, 9)
Match(a=1, b=0, size=4)

일치하는 블록이 없으면 (alo, blo, 0)를 반환합니다.

이 메서드는 네임드 튜플 Match(a, b, size)를 반환합니다.

버전 3.9에서 변경: 인자 기본값이 추가되었습니다.

get_matching_blocks()

중첩하지 않는 일치하는 서브 시퀀스를 기술하는 3-튜플의 리스트를 반환합니다. 각 3-튜플은 (i, j, n) 형식이며, a[i:i+n] == b[j:j+n]를 뜻합니다. 3-튜플은 i와 j에 대해 단조 증가합니다.

마지막 3-튜플은 더미이며, (len(a), len(b), 0) 값을 가집니다. n == 0 인 유일한 3-튜플입니다. (i, j, n)와 (i', j', n')가 리스트에서 인접한 3-튜플이고, 두 번째가 리스트의 마지막 3-튜플이 아니면 i+n < i' 또는 j+n < j'입니다; 즉, 인접 3-튜플은 항상 인접하지 않은 같은 블록을 나타냅니다.

>>> s = SequenceMatcher(None, "abxcd", "abcd")
>>> s.get_matching_blocks()
[Match(a=0, b=0, size=2), Match(a=3, b=2, size=2), Match(a=5, b=4, size=0)]

get_opcodes()

a를 b로 변환하는 방법을 설명하는 5-튜플의 리스트를 반환합니다. 각 튜플은 (tag, i1, i2, j1, j2) 형식입니다. 첫 번째 튜플은 i1 == j1 == 0 이고, 나머지 튜플에서는 i1이 이전 튜플의 i2와 같고, 마찬가지로 j1은 이전 j2와 같습니다.

tag 값은 문자열이고, 이런 의미입니다:

값

뜻

'replace'

a[i1:i2]를 b[j1:j2]로 치환해야 합니다.

'delete'

a[i1:i2]를 삭제해야 합니다. 이때 j1 == j2 임을 유의하십시오.

'insert'

b[j1:j2]을 a[i1:i1]에 삽입해야 합니다. 이때 i1 == i2 임을 유의하십시오.

'equal'

a[i1:i2] == b[j1:j2] (서브 시퀀스가 같습니다).

예를 들면:

>>> a = "qabxcd"
>>> b = "abycdf"
>>> s = SequenceMatcher(None, a, b)
>>> for tag, i1, i2, j1, j2 in s.get_opcodes():
...     print('{:7}   a[{}:{}] --> b[{}:{}] {!r:>8} --> {!r}'.format(
...         tag, i1, i2, j1, j2, a[i1:i2], b[j1:j2]))
delete    a[0:1] --> b[0:0]      'q' --> ''
equal     a[1:3] --> b[0:2]     'ab' --> 'ab'
replace   a[3:4] --> b[2:3]      'x' --> 'y'
equal     a[4:6] --> b[3:5]     'cd' --> 'cd'
insert    a[6:6] --> b[5:6]       '' --> 'f'

get_grouped_opcodes(n=3)

최대 n 줄의 문맥을 갖는 그룹의 제너레이터를 반환합니다.

get_opcodes()에서 반환된 그룹으로 출발해서, 이 메서드는 더 작은 변경 클러스터로 나누고, 변경 사항이 없는 중간 범위를 제거합니다.

그룹은 get_opcodes()와 같은 형식으로 반환됩니다.

ratio()

[0, 1]의 범위의 float로 시퀀스 유사성 척도를 돌려줍니다.

T가 두 시퀀스의 요소의 총 개수이고, M은 일치 개수일 때, 척도는 2.0*M / T입니다. 시퀀스가 같으면 1.0이고, 공통 요소가 없으면 0.0입니다.

get_matching_blocks() 나 get_opcodes()가 아직 호출되지 않았으면, 계산하는 데 비용이 많이 듭니다. 이럴 때, quick_ratio() 나 real_quick_ratio()를 먼저 시도하여 상한값을 얻을 수 있습니다.

참고

주의: ratio() 호출의 결과는 인자의 순서에 따라 달라질 수 있습니다. 예를 들어:

>>> SequenceMatcher(None, 'tide', 'diet').ratio()
0.25
>>> SequenceMatcher(None, 'diet', 'tide').ratio()
0.5

quick_ratio()

비교적 빨리 ratio()의 상한을 반환합니다.

real_quick_ratio()

아주 빨리 ratio()의 상한을 반환합니다.

The three methods that return the ratio of matching to total characters can give different results due to differing levels of approximation, although quick_ratio() and real_quick_ratio() are always at least as large as ratio():

>>> s = SequenceMatcher(None, "abcd", "bcde")
>>> s.ratio()
0.75
>>> s.quick_ratio()
0.75
>>> s.real_quick_ratio()
1.0

SequenceMatcher 예제

이 예제에서는 공백을 “정크”로 간주하여, 두 문자열을 비교합니다:

>>> s = SequenceMatcher(lambda x: x == " ",
...                     "private Thread currentThread;",
...                     "private volatile Thread currentThread;")

ratio() returns a float in [0, 1], measuring the similarity of the sequences. As a rule of thumb, a ratio() value over 0.6 means the sequences are close matches:

>>> print(round(s.ratio(), 3))
0.866

If you’re only interested in where the sequences match, get_matching_blocks() is handy:

>>> for block in s.get_matching_blocks():
...     print("a[%d] and b[%d] match for %d elements" % block)
a[0] and b[0] match for 8 elements
a[8] and b[17] match for 21 elements
a[29] and b[38] match for 0 elements

Note that the last tuple returned by get_matching_blocks() is always a dummy, (len(a), len(b), 0), and this is the only case in which the last tuple element (number of elements matched) is 0.

If you want to know how to change the first sequence into the second, use get_opcodes():

>>> for opcode in s.get_opcodes():
...     print("%6s a[%d:%d] b[%d:%d]" % opcode)
 equal a[0:8] b[0:8]
insert a[8:8] b[8:17]
 equal a[8:29] b[17:38]

더 보기

이 모듈의 get_close_matches() 함수는 SequenceMatcher를 사용한 간단한 코드 작성을 통해 유용한 작업을 수행하는 방법을 보여줍니다.

Simple version control recipe [https://code.activestate.com/recipes/576729-simple-version-control/] for a small application built with SequenceMatcher.

Differ 객체

Differ가 만든 델타는 최소 diff라고 주장하지 않음에 유의하십시오. 반대로, 최소 diff는 종종 반 직관적인데, 가능한 모든 곳에서 일치를 취하기 때문입니다. 때로 우발적으로 100페이지가 떨어진 곳에서 일치시키기도 합니다. 동기화 지점을 인접한 일치로 제한하면 가끔 더 긴 diff를 만드는 대신 일종의 지역성을 보존합니다.

Differ 클래스에는 다음과 같은 생성자가 있습니다:

class difflib.Differ(linejunk=None, charjunk=None)

선택적 키워드 매개 변수 linejunk 와 charjunk는 필터 함수(또는 None)를 위한 것입니다:

linejunk: 단일 문자열 인자를 받아들이고 문자열이 정크면 참을 반환하는 함수입니다. 기본값은 None이며, 이는 어떤 줄도 정크로 간주하지 않음을 의미합니다.

charjunk: 문자(길이 1의 문자열)를 받아들이고, 문자가 정크면 참을 반환하는 함수입니다. 기본값은 None이며, 이는 어떤 문자도 정크로 간주하지 않음을 의미합니다.

이러한 정크 필터링 함수는 차이점을 찾기 위한 일치 속도를 높이고 차이가 나는 줄이나 문자를 무시하지 않습니다. 설명이 필요하면 find_longest_match() 메서드의 isjunk 매개 변수에 대한 설명을 읽으십시오.

Differ 객체는 단일 메서드를 통해 사용됩니다 (델타가 만들어집니다):

compare(a, b)

줄의 시퀀스 두 개를 비교하고, 델타(줄의 시퀀스)를 만듭니다.

각 시퀀스는 줄 넘김으로 끝나는 개별 단일 줄 문자열을 포함해야 합니다. 이러한 시퀀스는 파일류 객체의 readlines() 메서드로 얻을 수 있습니다. 생성된 델타 역시 파일류 객체의 writelines() 메서드를 통해 그대로 인쇄될 수 있도록 줄 넘김으로 끝나는 문자열로 구성됩니다.

Differ 예제

This example compares two texts. First we set up the texts, sequences of individual single-line strings ending with newlines (such sequences can also be obtained from the readlines() method of file-like objects):

>>> text1 = '''  1. Beautiful is better than ugly.
...   2. Explicit is better than implicit.
...   3. Simple is better than complex.
...   4. Complex is better than complicated.
... '''.splitlines(keepends=True)
>>> len(text1)
4
>>> text1[0][-1]
'\n'
>>> text2 = '''  1. Beautiful is better than ugly.
...   3.   Simple is better than complex.
...   4. Complicated is better than complex.
...   5. Flat is better than nested.
... '''.splitlines(keepends=True)

다음으로 Differ 객체의 인스턴스를 만듭니다:

>>> d = Differ()

Differ 객체의 인스턴스를 만들 때, 줄과 문자 “정크”를 필터링하는 함수를 전달할 수 있음에 유의하십시오. 자세한 내용은 Differ() 생성자를 참조하십시오.

마지막으로, 두 개를 비교합니다:

>>> result = list(d.compare(text1, text2))

result는 문자열의 리스트이므로, 예쁜 인쇄를 해봅시다:

>>> from pprint import pprint
>>> pprint(result)
['    1. Beautiful is better than ugly.\n',
 '-   2. Explicit is better than implicit.\n',
 '-   3. Simple is better than complex.\n',
 '+   3.   Simple is better than complex.\n',
 '?     ++\n',
 '-   4. Complex is better than complicated.\n',
 '?            ^                     ---- ^\n',
 '+   4. Complicated is better than complex.\n',
 '?           ++++ ^                      ^\n',
 '+   5. Flat is better than nested.\n']

여러 줄이 포함된 하나의 문자열로 만들면 이렇게 보입니다:

>>> import sys
>>> sys.stdout.writelines(result)
    1. Beautiful is better than ugly.
-   2. Explicit is better than implicit.
-   3. Simple is better than complex.
+   3.   Simple is better than complex.
?     ++
-   4. Complex is better than complicated.
?            ^                     ---- ^
+   4. Complicated is better than complex.
?           ++++ ^                      ^
+   5. Flat is better than nested.

difflib의 명령 줄 인터페이스

This example shows how to use difflib to create a diff-like utility.

""" Command line interface to difflib.py providing diffs in four formats:

* ndiff:    lists every line and highlights interline changes.
* context:  highlights clusters of changes in a before/after format.
* unified:  highlights clusters of changes in an inline format.
* html:     generates side by side comparison with change highlights.

"""

import sys, os, difflib, argparse
from datetime import datetime, timezone

def file_mtime(path):
    t = datetime.fromtimestamp(os.stat(path).st_mtime,
                               timezone.utc)
    return t.astimezone().isoformat()

def main():

    parser = argparse.ArgumentParser()
    parser.add_argument('-c', action='store_true', default=False,
                        help='Produce a context format diff (default)')
    parser.add_argument('-u', action='store_true', default=False,
                        help='Produce a unified format diff')
    parser.add_argument('-m', action='store_true', default=False,
                        help='Produce HTML side by side diff '
                             '(can use -c and -l in conjunction)')
    parser.add_argument('-n', action='store_true', default=False,
                        help='Produce a ndiff format diff')
    parser.add_argument('-l', '--lines', type=int, default=3,
                        help='Set number of context lines (default 3)')
    parser.add_argument('fromfile')
    parser.add_argument('tofile')
    options = parser.parse_args()

    n = options.lines
    fromfile = options.fromfile
    tofile = options.tofile

    fromdate = file_mtime(fromfile)
    todate = file_mtime(tofile)
    with open(fromfile) as ff:
        fromlines = ff.readlines()
    with open(tofile) as tf:
        tolines = tf.readlines()

    if options.u:
        diff = difflib.unified_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)
    elif options.n:
        diff = difflib.ndiff(fromlines, tolines)
    elif options.m:
        diff = difflib.HtmlDiff().make_file(fromlines,tolines,fromfile,tofile,context=options.c,numlines=n)
    else:
        diff = difflib.context_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)

    sys.stdout.writelines(diff)

if __name__ == '__main__':
    main()

ndiff example

This example shows how to use difflib.ndiff().

"""ndiff [-q] file1 file2
    or
ndiff (-r1 | -r2) < ndiff_output > file1_or_file2

Print a human-friendly file difference report to stdout.  Both inter-
and intra-line differences are noted.  In the second form, recreate file1
(-r1) or file2 (-r2) on stdout, from an ndiff report on stdin.

In the first form, if -q ("quiet") is not specified, the first two lines
of output are

-: file1
+: file2

Each remaining line begins with a two-letter code:

    "- "    line unique to file1
    "+ "    line unique to file2
    "  "    line common to both files
    "? "    line not present in either input file

Lines beginning with "? " attempt to guide the eye to intraline
differences, and were not present in either input file.  These lines can be
confusing if the source files contain tab characters.

The first file can be recovered by retaining only lines that begin with
"  " or "- ", and deleting those 2-character prefixes; use ndiff with -r1.

The second file can be recovered similarly, but by retaining only "  " and
"+ " lines; use ndiff with -r2; or, on Unix, the second file can be
recovered by piping the output through

    sed -n '/^[+ ] /s/^..//p'
"""

__version__ = 1, 7, 0

import difflib, sys

def fail(msg):
    out = sys.stderr.write
    out(msg + "\n\n")
    out(__doc__)
    return 0

# open a file & return the file object; gripe and return 0 if it
# couldn't be opened
def fopen(fname):
    try:
        return open(fname)
    except IOError as detail:
        return fail("couldn't open " + fname + ": " + str(detail))

# open two files & spray the diff to stdout; return false iff a problem
def fcompare(f1name, f2name):
    f1 = fopen(f1name)
    f2 = fopen(f2name)
    if not f1 or not f2:
        return 0

    a = f1.readlines(); f1.close()
    b = f2.readlines(); f2.close()
    for line in difflib.ndiff(a, b):
        print(line, end=' ')

    return 1

# crack args (sys.argv[1:] is normal) & compare;
# return false iff a problem

def main(args):
    import getopt
    try:
        opts, args = getopt.getopt(args, "qr:")
    except getopt.error as detail:
        return fail(str(detail))
    noisy = 1
    qseen = rseen = 0
    for opt, val in opts:
        if opt == "-q":
            qseen = 1
            noisy = 0
        elif opt == "-r":
            rseen = 1
            whichfile = val
    if qseen and rseen:
        return fail("can't specify both -q and -r")
    if rseen:
        if args:
            return fail("no args allowed with -r option")
        if whichfile in ("1", "2"):
            restore(whichfile)
            return 1
        return fail("-r value must be 1 or 2")
    if len(args) != 2:
        return fail("need 2 filename args")
    f1name, f2name = args
    if noisy:
        print('-:', f1name)
        print('+:', f2name)
    return fcompare(f1name, f2name)

# read ndiff output from stdin, and print file1 (which=='1') or
# file2 (which=='2') to stdout

def restore(which):
    restored = difflib.restore(sys.stdin.readlines(), which)
    sys.stdout.writelines(restored)

if __name__ == '__main__':
    main(sys.argv[1:])

textwrap — Text wrapping and filling

소스 코드: Lib/textwrap.py [https://github.com/python/cpython/tree/main/Lib/textwrap.py]

textwrap 모듈은 모든 작업을 수행하는 클래스인 TextWrapper뿐만 아니라 몇 가지 편리 함수도 제공합니다. 한두 개의 텍스트 문자열을 래핑(wrapping)하거나 채운(filling)다면, 편리 함수로도 충분해야 합니다; 그렇지 않으면 효율을 위해 TextWrapper 인스턴스를 사용해야 합니다.

textwrap.wrap(text, width=70, *, initial_indent='', subsequent_indent='', expand_tabs=True, replace_whitespace=True, fix_sentence_endings=False, break_long_words=True, drop_whitespace=True, break_on_hyphens=True, tabsize=8, max_lines=None, placeholder=' [...]')

text(문자열)에 있는 단일 문단을 래핑해서 모든 줄의 길이가 최대 width 자가 되도록 합니다. 최종 줄 바꿈이 없는 출력 줄의 리스트를 반환합니다.

Optional keyword arguments correspond to the instance attributes of TextWrapper, documented below.

wrap() 작동 방식에 대한 자세한 내용은 TextWrapper.wrap() 메서드를 참조하십시오.

textwrap.fill(text, width=70, *, initial_indent='', subsequent_indent='', expand_tabs=True, replace_whitespace=True, fix_sentence_endings=False, break_long_words=True, drop_whitespace=True, break_on_hyphens=True, tabsize=8, max_lines=None, placeholder=' [...]')

text에 있는 단일 문단을 래핑하고, 래핑 된 문단을 포함하는 단일 문자열을 반환합니다. fill()은 다음의 줄임 표현입니다

"\n".join(wrap(text, ...))

특히, fill()은 wrap()과 같은 키워드 인자를 받아들입니다.

textwrap.shorten(text, width, *, fix_sentence_endings=False, break_long_words=True, break_on_hyphens=True, placeholder=' [...]')

주어진 width에 맞게 주어진 text를 축약하거나 자릅니다.

First the whitespace in text is collapsed (all whitespace is replaced by single spaces). If the result fits in the width, it is returned. Otherwise, enough words are dropped from the end so that the remaining words plus the placeholder fit within width:

>>> textwrap.shorten("Hello  world!", width=12)
'Hello world!'
>>> textwrap.shorten("Hello  world!", width=11)
'Hello [...]'
>>> textwrap.shorten("Hello world", width=10, placeholder="...")
'Hello...'

선택적 키워드 인자는 아래에 설명된 TextWrapper의 인스턴스 어트리뷰트에 해당합니다. 텍스트가 TextWrapper fill() 함수에 전달되기 전에 공백이 축약되므로, tabsize, expand_tabs, drop_whitespace 및 replace_whitespace 값을 변경하는 것은 아무 효과가 없음에 유의하십시오.

Added in version 3.4.

textwrap.dedent(text)

text의 모든 줄에서 같은 선행 공백을 제거합니다.

이것은 삼중 따옴표로 묶은 문자열을 소스 코드에서 여전히 들여쓰기 된 형태로 제시하면서, 디스플레이의 왼쪽 가장자리에 맞추는 데 사용할 수 있습니다.

탭과 공백은 모두 공백으로 처리되지만, 이들이 같지 않음에 유의하십시오: "  hello"와 "\thello" 줄에는 공통 선행 공백이 없는 것으로 간주합니다.

공백만 포함하는 줄은 입력에서 무시되고 출력에서 단일 개행 문자로 정규화됩니다.

예를 들면:

def test():
    # end first line with \ to avoid the empty line!
    s = '''\
    hello
      world
    '''
    print(repr(s))          # prints '    hello\n      world\n    '
    print(repr(dedent(s)))  # prints 'hello\n  world\n'

textwrap.indent(text, prefix, predicate=None)

text에서 선택된 줄의 시작 부분에 prefix를 추가합니다.

text.splitlines(True)를 호출하여 줄을 분할합니다.

기본적으로, prefix는 공백으로만 구성되지 않는 모든 줄(마지막 줄 포함)에 추가됩니다.

예를 들면:

>>> s = 'hello\n\n \nworld'
>>> indent(s, '  ')
'  hello\n\n \n  world'

선택적 predicate 인자는 어떤 줄을 들여쓰기할지 제어하는 데 사용될 수 있습니다. 예를 들어, 빈 줄과 공백만 있는 줄에도 prefix를 추가하기는 쉽습니다:

>>> print(indent(s, '+ ', lambda line: True))
+ hello
+
+
+ world

Added in version 3.3.

wrap(), fill() 및 shorten()은 TextWrapper 인스턴스를 만들고 그것의 단일 메서드를 호출하여 작동합니다. 이 인스턴스는 재사용되지 않기 때문에, wrap() 및/또는 fill()을 사용하여 많은 텍스트 문자열을 처리하는 응용 프로그램의 경우, 여러분 자신의 TextWrapper 객체를 만드는 것이 더 효율적일 수 있습니다.

텍스트는 공백과 하이픈이 있는 단어의 하이픈 바로 뒤에서 래핑하는 것을 선호합니다; TextWrapper.break_long_words가 거짓으로 설정되어 있지 않으면 그 후에만 긴 단어를 분할합니다.

class textwrap.TextWrapper(**kwargs)

TextWrapper 생성자는 여러 개의 선택적 키워드 인자를 받아들입니다. 각 키워드 인자는 인스턴스 어트리뷰트에 해당합니다, 그래서 예를 들면

wrapper = TextWrapper(initial_indent="* ")

는 다음과 같습니다

wrapper = TextWrapper()
wrapper.initial_indent = "* "

You can reuse the same TextWrapper object many times, and you can change any of its options through direct assignment to instance attributes between uses.

TextWrapper 인스턴스 어트리뷰트(와 생성자에 대한 키워드 인자)는 다음과 같습니다:

width

(기본값: 70) 래핑 된 줄의 최대 길이. 입력 텍스트에 width보다 긴 개별 단어가 없는 한, TextWrapper는 width 문자보다 긴 출력 줄이 없음을 보장합니다.

expand_tabs

(default: True) If true, then all tab characters in text will be expanded to spaces using the expandtabs() method of text.

tabsize

(기본값: 8) expand_tabs가 참이면, text의 모든 탭 문자는 현재 열과 주어진 탭 크기에 따라 0개 이상의 스페이스로 확장됩니다.

Added in version 3.3.

replace_whitespace

(기본값: True) 참이면, 탭 확장 후 래핑 전에, wrap() 메서드는 각 공백 문자를 단일 스페이스로 치환합니다. 치환되는 공백 문자는 다음과 같습니다: 탭, 줄 바꿈, 세로 탭, 폼 피드 및 캐리지 리턴 ('\t\n\v\f\r').

참고

expand_tabs가 거짓이고 replace_whitespace가 참이면, 각 탭 문자는 단일 스페이스로 치환되는데, 탭 확장과는 다릅니다.

참고

replace_whitespace가 거짓이면, 줄 중간에 줄 바꿈이 나타나서 이상한 결과가 발생할 수 있습니다. 이러한 이유로, 텍스트는 (str.splitlines()나 유사한 것을 사용해서) 문단으로 분할한 후에 별도로 래핑해야 합니다.

drop_whitespace

(기본값: True) 참이면, 모든 줄의 처음과 끝의 공백(래핑 이후 들여쓰기 전)이 삭제됩니다. 문단 시작 부분의 공백은 공백이 아닌 것이 뒤에 오면 삭제되지 않습니다. 삭제되는 공백이 줄 전체를 차지하면, 줄 전체가 삭제됩니다.

initial_indent

(기본값: '') 래핑 된 출력의 첫 번째 줄 앞에 추가될 문자열입니다. 첫 번째 줄의 길이 계산에 포함됩니다. 빈 문자열은 들여 쓰지 않습니다.

subsequent_indent

(기본값: '') 첫 줄을 제외한 래핑 된 출력의 모든 줄 앞에 추가될 문자열입니다. 첫 번째 줄을 제외한 각 줄의 길이 계산에 포함됩니다.

fix_sentence_endings

(default: False) If true, TextWrapper attempts to detect sentence endings and ensure that sentences are always separated by exactly two spaces. This is generally desired for text in a monospaced font. However, the sentence detection algorithm is imperfect: it assumes that a sentence ending consists of a lowercase letter followed by one of '.', '!', or '?', possibly followed by one of '"' or "'", followed by a space. One problem with this algorithm is that it is unable to detect the difference between “Dr.” in

[...] Dr. Frankenstein's monster [...]

다음에 나오는 “Spot.” 사이의 차이점을 탐지할 수 없다는 것입니다

[...] See Spot. See Spot run [...]

fix_sentence_endings는 기본적으로 거짓입니다.

문장 감지 알고리즘은 “소문자” 의 정의에 string.lowercase에 의존하고, 같은 줄에서 문장을 분리하기 위해 마침표 뒤에 두 개의 스페이스를 사용하는 규칙을 따르므로, 영어 텍스트에만 적용됩니다.

break_long_words

(기본값: True) 참이면, width보다 긴 줄이 없도록 하기 위해, width보다 긴 단어를 분할합니다. 거짓이면, 긴 단어가 깨지지 않으며, 일부 줄이 width보다 길 수 있습니다. (width를 초과하는 양을 최소화하기 위해 긴 단어는 독립된 줄에 넣습니다.)

break_on_hyphens

(기본값: True) 참이면, 래핑이, 영어에서의 관례대로, 공백과 복합 단어의 하이픈 바로 뒤에서 발생합니다. 거짓이면, 공백만을 줄 바꿈을 위한 좋은 장소로 간주하지만, 진정한 분할되지 않는 단어를 원한다면 break_long_words를 거짓으로 설정해야 합니다. 이전 버전의 기본 동작은 항상 하이픈으로 연결된 단어를 분리 할 수 있게 하는 것이었습니다.

max_lines

(기본값: None) None이 아니면, 출력은 최대 max_lines 줄을 포함하고, placeholder가 출력 끝에 나타납니다.

Added in version 3.4.

placeholder

(기본값: ' [...]') 잘렸을 때 출력 텍스트의 끝에 표시할 문자열.

Added in version 3.4.

TextWrapper는 모듈 수준 편리 함수와 유사한 몇 가지 공용 메서드도 제공합니다:

wrap(text)

text(문자열)에 있는 한 문단을 모든 줄의 길이가 최대 width 자가 되도록 래핑합니다. 모든 래핑 옵션은 TextWrapper 인스턴스의 인스턴스 어트리뷰트에서 가져옵니다. 최종 줄 바꿈이 없는 출력 줄의 리스트를 반환합니다. 래핑 된 출력에 내용이 없으면 반환된 리스트는 비어 있습니다.

fill(text)

text에 있는 단일 문단을 래핑하고, 래핑 된 문단을 포함하는 단일 문자열을 반환합니다.

unicodedata — Unicode Database

This module provides access to the Unicode Character Database (UCD) which defines character properties for all Unicode characters. The data contained in this database is compiled from the UCD version 16.0.0 [https://www.unicode.org/Public/16.0.0/ucd].

모듈은 유니코드 표준 부속서 #44, “유니코드 문자 데이터베이스” [https://www.unicode.org/reports/tr44/]에 정의된 것과 같은 이름과 기호를 사용합니다. 다음과 같은 함수를 정의합니다:

unicodedata.lookup(name)

이름으로 문자를 조회합니다. 지정된 이름의 문자가 발견되면, 대응하는 문자를 돌려줍니다. 발견되지 않으면, KeyError가 발생합니다.

버전 3.3에서 변경: 이름 별칭 [1] 과 명명된 시퀀스 [2] 가 추가되었습니다.

unicodedata.name(chr[, default])

chr 문자에 할당된 이름을 문자열로 반환합니다. 이름이 정의되지 않으면, default가 반환되거나, 지정되지 않으면 ValueError가 발생합니다.

unicodedata.decimal(chr[, default])

chr 문자에 할당된 10진수 값을 정수로 반환합니다. 그러한 값이 정의되어 있지 않으면 default가 반환되거나, 지정되지 않으면 ValueError가 발생합니다.

unicodedata.digit(chr[, default])

chr 문자에 할당된 숫자(digit) 값을 정수로 반환합니다. 그러한 값이 정의되어 있지 않으면 default가 반환되거나, 지정되지 않으면 ValueError가 발생합니다.

unicodedata.numeric(chr[, default])

chr 문자에 할당된 수치(numeric value)를 float로 반환합니다. 그러한 값이 정의되어 있지 않으면 default가 반환되거나, 지정되지 않으면 ValueError가 발생합니다.

unicodedata.category(chr)

chr 문자에 할당된 일반 범주(general category)를 문자열로 반환합니다.

unicodedata.bidirectional(chr)

chr 문자에 할당된 양방향 클래스(bidirectional class)를 문자열로 반환합니다. 그러한 값이 정의되어 있지 않으면, 빈 문자열이 반환됩니다.

unicodedata.combining(chr)

chr 문자에 할당된 정준 결합 클래스(canonical combining class)를 정수로 반환합니다. 결합 클래스가 정의되지 않으면 0을 반환합니다.

unicodedata.east_asian_width(chr)

문자 chr에 할당된 동아시아 폭(east asian width)을 문자열로 반환합니다.

unicodedata.mirrored(chr)

문자 chr에 할당된 거울상 속성(mirrored property)을 정수로 반환합니다. 문자가 양방향 텍스트에서 “거울상” 문자로 식별되면 1을 반환하고, 그렇지 않으면 0을 반환합니다.

unicodedata.decomposition(chr)

문자 chr에 할당된 문자 분해 매핑(character decomposition mapping)을 문자열로 반환합니다. 그러한 매핑이 정의되어 있지 않으면 빈 문자열이 반환됩니다.

unicodedata.normalize(form, unistr)

유니코드 문자열 unistr에 대한 정규화 형식(normal form) form을 반환합니다. form의 유효한 값은 ‘NFC’, ‘NFKC’, ‘NFD’ 및 ‘NFKD’ 입니다.

유니코드 표준은 정준 동등성(canonical equivalence) 및 호환 동등성(compatibility equivalence)의 정의를 기반으로, 유니코드 문자열의 다양한 정규화 형식을 정의합니다. 유니코드에서, 여러 문자를 다양한 방법으로 표현할 수 있습니다. 예를 들어, U+00C7 (LATIN CAPITAL LETTER C WITH CEDILLA) 은 시퀀스 U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA) 로도 표현할 수 있습니다.

각 문자에는, 두 개의 정규화 형식이 있습니다: 정규화 형식 C와 정규화 형식 D. 정규화 형식 D(NFD)는 정준 분해라고도 하며, 각 문자를 분해된 형식으로 변환합니다. 정규화 형식 C(NFC)는 먼저 정준 분해를 적용한 다음, 미리 결합한 문자로 다시 조합합니다.

이 두 형식 외에도, 호환 등가성을 기반으로 하는 두 가지 추가 정규화 형식이 있습니다. 유니코드에서는, 일반적으로 다른 문자와 통합되는 특정 문자가 지원됩니다. 예를 들어, U+2160 (ROMAN NUMERAL ONE) 은 U+0049 (LATIN CAPITAL LETTER I) 과 실제로 같습니다. 하지만, 기존 문자 집합(예를 들어, gb2312)과의 호환성을 위해 유니코드에서 지원됩니다.

정규화 형식 KD(NFKD)는 호환 분해를 적용합니다. 즉, 모든 호환 문자를 동등한 것으로 치환합니다. 정규화 형식 KC(NFKC)는 먼저 호환 분해를 적용한 다음, 정준 결합을 적용합니다.

두 개의 유니코드 문자열이 정규화되고, 사람이 보기에 같아 보여도, 하나가 결합한 문자를 갖고 다른 것은 그렇지 않으면, 같다고 비교되지 않을 수 있습니다.

unicodedata.is_normalized(form, unistr)

유니코드 문자열 unistr이 정규화 형식 form인지를 반환합니다. form의 유효한 값은 ‘NFC’, ‘NFKC’, ‘NFD’ 및 ‘NFKD’ 입니다.

Added in version 3.8.

또한, 이 모듈은 다음 상수를 노출합니다:

unicodedata.unidata_version

이 모듈에 사용된 유니코드 데이터베이스의 버전.

unicodedata.ucd_3_2_0

이것은 전체 모듈과 같은 메서드를 가지고 있는 객체이지만, 유니코드 데이터베이스 버전 3.2를 대신 사용합니다. 이 특정 버전의 유니코드 데이터베이스가 필요한 응용 프로그램(가령 IDNA)을 위한 것입니다.

예제:

>>> import unicodedata
>>> unicodedata.lookup('LEFT CURLY BRACKET')
'{'
>>> unicodedata.name('/')
'SOLIDUS'
>>> unicodedata.decimal('9')
9
>>> unicodedata.decimal('a')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: not a decimal
>>> unicodedata.category('A')  # 'L'etter, 'u'ppercase
'Lu'
>>> unicodedata.bidirectional('\u0660') # 'A'rabic, 'N'umber
'AN'

각주

[1]

https://www.unicode.org/Public/16.0.0/ucd/NameAliases.txt

[2]

https://www.unicode.org/Public/16.0.0/ucd/NamedSequences.txt

stringprep — Internet String Preparation

소스 코드: Lib/stringprep.py [https://github.com/python/cpython/tree/main/Lib/stringprep.py]

인터넷에서 무언가(가령 호스트 이름)를 식별할 때, 종종 그러한 식별에 대해 “동등” 비교할 필요가 있습니다. 이 비교가 실행되는 정확한 방법은 응용 프로그램 도메인에 따라 달라질 수 있습니다, 예를 들어 대/소문자를 구분하는지 그렇지 않은지. 또한 “인쇄 가능” 문자로만 구성된 식별만 허용하기 위해, 가능한 식별을 제한해야 할 수도 있습니다.

RFC 3454 [https://datatracker.ietf.org/doc/html/rfc3454.html]는 인터넷 프로토콜에서 유니코드 문자열을 “준비” 하는 절차를 정의합니다. 문자열을 전선에 전달하기 전에, 준비 절차를 통해 문자열을 처리해서 어떤 정규화된 형식을 갖도록 만듭니다. RFC는 프로파일로 결합할 수 있는 테이블 집합을 정의합니다. 각 프로파일은 사용하는 테이블과 stringprep 절차의 어떤 선택적 부분이 프로파일 일부인지 정의해야 합니다. stringprep 프로파일의 한 가지 예는 국제화된 도메인 이름에 사용되는 nameprep입니다.

The module stringprep only exposes the tables from RFC 3454 [https://datatracker.ietf.org/doc/html/rfc3454.html]. As these tables would be very large to represent as dictionaries or lists, the module uses the Unicode character database internally. The module source code itself was generated using the mkstringprep.py utility.

결과적으로, 이러한 테이블은 데이터 구조가 아닌 함수로 노출됩니다. RFC에는 두 종류의 테이블이 있습니다: 집합과 매핑. 집합의 경우, stringprep는 “특성 함수”, 즉 매개 변수가 집합 일부면 True를 반환하는 함수를 제공합니다. 매핑의 경우, 매핑 함수를 제공합니다: 주어진 키에 대해, 연관된 값을 반환합니다. 다음은 모듈에서 사용할 수 있는 모든 함수의 목록입니다.

stringprep.in_table_a1(code)

code가 tableA.1(유니코드 3.2에서 지정되지 않은 코드 포인트)에 있는지 판별합니다.

stringprep.in_table_b1(code)

code가 tableB.1(일반적으로 아무것도 매핑되지 않습니다)에 있는지 판별합니다.

stringprep.map_table_b2(code)

tableB.2(NFKC와 함께 사용되는 케이스 폴딩용 매핑)에 따라 code의 매핑 된 값을 반환합니다.

stringprep.map_table_b3(code)

tableB.3(정규화가 없는 케이스 폴딩용 매핑)에 따라 code의 매핑 된 값을 반환합니다.

stringprep.in_table_c11(code)

code가 tableC.1.1(ASCII 스페이스 문자)에 있는지 판별합니다.

stringprep.in_table_c12(code)

code가 tableC.1.2(비 ASCII 스페이스 문자)에 있는지 판별합니다.

stringprep.in_table_c11_c12(code)

code가 tableC.1(스페이스 문자, C.1.1과 C.1.2의 합집합)에 있는지 판별합니다.

stringprep.in_table_c21(code)

code가 tableC.2.1(ASCII 제어 문자)에 있는지 판별합니다.

stringprep.in_table_c22(code)

code가 tableC.2.2(비 ASCII 제어 문자)에 있는지 판별합니다.

stringprep.in_table_c21_c22(code)

code가 tableC.2(제어 문자, C.2.1과 C.2.2의 합집합)에 있는지 판별합니다.

stringprep.in_table_c3(code)

code가 tableC.3(개인 사용)에 있는지 판별합니다.

stringprep.in_table_c4(code)

code가 tableC.4(비문자 코드 포인트)에 있는지 판별합니다.

stringprep.in_table_c5(code)

code가 tableC.5(대리 코드)에 있는지 판별합니다.

stringprep.in_table_c6(code)

code가 tableC.6(일반 텍스트에는 부적절)에 있는지 판별합니다.

stringprep.in_table_c7(code)

code가 tableC.7(규범적 표현에는 부적절)에 있는지 판별합니다.

stringprep.in_table_c8(code)

code가 tableC.8(표시 특성 변경 또는 폐지)에 있는지 판별합니다.

stringprep.in_table_c9(code)

code가 tableC.9(문자 태깅)에 있는지 판별합니다.

stringprep.in_table_d1(code)

code가 tableD.1(양방향 특성이 “R”이나 “AL”인 문자)에 있는지 판별합니다.

stringprep.in_table_d2(code)

code가 tableD.2(양방향 특성이 “L”인 문자)에 있는지 판별합니다.

readline — GNU readline interface

readline 모듈은 파이썬 인터프리터에서 완성(completion)과 히스토리 파일의 읽기/쓰기를 용이하게 하는 여러 함수를 정의합니다. 이 모듈은 직접 사용하거나, 대화식 프롬프트에서 파이썬 식별자 완성을 지원하는 rlcompleter 모듈을 통해 사용할 수 있습니다. 이 모듈을 사용하여 설정한 내용은 인터프리터의 대화식 프롬프트와 내장 input() 함수가 제공하는 프롬프트의 동작에 영향을 줍니다.

Readline keybindings may be configured via an initialization file, typically .inputrc in your home directory. See Readline Init File [https://tiswww.cwru.edu/php/chet/readline/rluserman.html#Readline-Init-File] in the GNU Readline manual for information about the format and allowable constructs of that file, and the capabilities of the Readline library in general.

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

참고

The underlying Readline library API may be implemented by the editline (libedit) library instead of GNU readline. On macOS the readline module detects which library is being used at run time.

The configuration file for editline is different from that of GNU readline. If you programmatically load configuration strings you can use backend to determine which library is being used.

If you use editline/libedit readline emulation on macOS, the initialization file located in your home directory is named .editrc. For example, the following content in ~/.editrc will turn ON vi keybindings and TAB completion:

python:bind -v
python:bind ^I rl_complete

Also note that different libraries may use different history file formats. When switching the underlying library, existing history files may become unusable.

readline.backend

The name of the underlying Readline library being used, either "readline" or "editline".

Added in version 3.13.

초기화 파일

다음 함수는 초기화 파일 및 사용자 구성과 관련이 있습니다:

readline.parse_and_bind(string)

string 인자에 제공된 초기화 줄을 실행합니다. 하부 라이브러리에서 rl_parse_and_bind()를 호출합니다.

readline.read_init_file([filename])

readline 초기화 파일을 실행합니다. 기본 파일 이름은 마지막으로 사용한 파일 이름입니다. 하부 라이브러리에서 rl_read_init_file()을 호출합니다.

줄 버퍼

다음 함수는 라인 버퍼에 대해 작용합니다:

readline.get_line_buffer()

줄 버퍼의 현재 내용(하부 라이브러리의 rl_line_buffer)을 반환합니다.

readline.insert_text(string)

줄 버퍼의 커서 위치에 텍스트를 삽입합니다. 하부 라이브러리에서 rl_insert_text()를 호출하지만, 반환 값은 무시합니다.

readline.redisplay()

줄 버퍼의 현재 내용을 반영하도록 화면에 표시되는 내용을 변경합니다. 하부 라이브러리에서 rl_redisplay()를 호출합니다.

히스토리 파일

다음 함수는 히스토리 파일에 대해 작용합니다:

readline.read_history_file([filename])

readline 히스토리 파일을 로드하고, 히스토리 목록에 추가합니다. 기본 파일명은 ~/.history입니다. 하부 라이브러리에서 read_history()를 호출합니다.

readline.write_history_file([filename])

히스토리 목록을 readline 히스토리 파일에 저장하여, 기존 파일을 덮어씁니다. 기본 파일명은 ~/.history입니다. 하부 라이브러리에서 write_history()를 호출합니다.

readline.append_history_file(nelements[, filename])

히스토리의 마지막 nelements 항목을 파일에 추가합니다. 기본 파일명은 ~/.history입니다. 파일이 이미 존재해야 합니다. 하부 라이브러리에서 append_history()를 호출합니다. 이 함수는 파이썬이 이를 지원하는 라이브러리 버전으로 컴파일된 경우에만 존재합니다.

Added in version 3.5.

readline.get_history_length()

readline.set_history_length(length)

히스토리 파일에 저장하기 원하는 줄 수를 설정하거나 반환합니다. write_history_file() 함수는 이 값을 사용하여, 하부 라이브러리에서 history_truncate_file()을 호출하여 히스토리 파일을 자릅니다. 음수 값은 제한 없는 히스토리 파일 크기를 의미합니다.

히스토리 목록

다음 함수는 전역 히스토리 목록에 대해 작용합니다:

readline.clear_history()

현재 히스토리를 지웁니다. 하부 라이브러리에서 clear_history()를 호출합니다. 파이썬 함수는 파이썬이 이를 지원하는 라이브러리 버전으로 컴파일된 경우에만 존재합니다.

readline.get_current_history_length()

현재 히스토리에 있는 항목 수를 반환합니다. (이것은 히스토리 파일에 기록될 최대 줄 수를 반환하는 get_history_length()와 다릅니다.)

readline.get_history_item(index)

index에 있는 히스토리 항목의 현재 내용을 반환합니다. 항목 인덱스는 1부터 시작합니다. 하부 라이브러리에서 history_get()을 호출합니다.

readline.remove_history_item(pos)

히스토리에서 위치(pos)로 지정된 히스토리 항목을 제거합니다. 위치는 0부터 시작합니다. 하부 라이브러리에서 remove_history()를 호출합니다.

readline.replace_history_item(pos, line)

위치(pos)로 지정된 히스토리 항목을 line으로 교체합니다. 위치는 0부터 시작합니다. 하부 라이브러리에서 replace_history_entry()를 호출합니다.

readline.add_history(line)

마지막 줄이 입력된 것처럼 히스토리 버퍼에 line을 추가합니다. 하부 라이브러리에서 add_history()를 호출합니다.

readline.set_auto_history(enabled)

readline을 통해 입력을 읽을 때 add_history()에 대한 자동 호출을 활성화 또는 비활성화합니다. enabled 인자는 참일 때 자동 히스토리를 활성화하고, 거짓일 때 자동 기록을 비활성화하는 불리언 값이어야 합니다.

Added in version 3.6.

CPython 구현 상세: Auto history is enabled by default, and changes to this do not persist across multiple sessions.

시동 훅

readline.set_startup_hook([function])

하부 라이브러리의 rl_startup_hook 콜백에 의해 호출되는 함수를 설정하거나 제거합니다. function이 지정되면 새 훅(hook) 함수로 사용됩니다; 생략되거나 None이면, 이미 설치된 함수가 제거됩니다. 이 훅은 readline이 첫 번째 프롬프트를 인쇄하기 직전에 인자 없이 호출됩니다.

readline.set_pre_input_hook([function])

하부 라이브러리의 rl_pre_input_hook 콜백에 의해 호출되는 함수를 설정하거나 제거합니다. function이 지정되면, 새 훅 함수로 사용됩니다; 생략되거나 None이면, 이미 설치된 함수가 제거됩니다. 이 훅은 첫 번째 프롬프트가 인쇄된 후 readline이 입력 문자를 읽기 시작하기 직전에 인자 없이 호출됩니다. 이 함수는 파이썬이 이를 지원하는 라이브러리 버전으로 컴파일된 경우에만 존재합니다.

완성

다음 함수는 사용자 정의 단어 완성 기능 구현과 관련이 있습니다. 이것은 일반적으로 Tab 키로 작동하며, 입력되는 단어를 제안하고 자동으로 완성할 수 있습니다. 기본적으로, Readline은 대화식 인터프리터를 위해 파이썬 식별자를 완성하는 rlcompleter에서 사용하도록 설정되어 있습니다. readline 모듈을 사용자 정의 완성기와 함께 사용하려면, 다른 단어 구분자 집합을 설정해야 합니다.

readline.set_completer([function])

완성 함수를 설정하거나 제거합니다. function이 지정되면 새 완성 함수로 사용됩니다; 생략하거나 None이면, 이미 설치된 완성 함수가 제거됩니다. 완성 함수는 문자열이 아닌 값을 반환할 때까지 0, 1, 2 등의 state에 대해 function(text, state)로 호출됩니다. text로 시작하는 다음으로 가능한 완성을 반환해야 합니다.

설치된 완성 함수는 하부 라이브러리의 rl_completion_matches()로 전달된 entry_func 콜백에 의해 호출됩니다. text 문자열은 하부 라이브러리의 rl_attempted_completion_function 콜백의 첫 번째 매개 변수로부터 옵니다.

readline.get_completer()

완성 함수나, 완성 함수가 설정되지 않았으면 None을 얻습니다.

readline.get_completion_type()

시도 중인 완성 유형을 가져옵니다. 하부 라이브러리의 rl_completion_type 변수를 정수로 반환합니다.

readline.get_begidx()

readline.get_endidx()

Get the beginning or ending index of the completion scope. These indexes are the start and end arguments passed to the rl_attempted_completion_function callback of the underlying library. The values may be different in the same input editing scenario based on the underlying C readline implementation. Ex: libedit is known to behave differently than libreadline.

readline.set_completer_delims(string)

readline.get_completer_delims()

완성을 위한 단어 구분자를 설정하거나 가져옵니다. 이것들은 완성을 위해 고려할 단어의 시작(완성 범위)을 결정합니다. 이 함수는 하부 라이브러리의 rl_completer_word_break_characters 변수를 액세스합니다.

readline.set_completion_display_matches_hook([function])

완성 표시 함수를 설정하거나 제거합니다. function이 지정되면, 새로운 완성 표시 함수로 사용됩니다; 생략하거나 None이면, 이미 설치된 완성 표시 함수가 제거됩니다. 하부 라이브러리에서 rl_completion_display_matches_hook 콜백을 설정하거나 지웁니다. 완성 표시 함수는 일치를 표시해야 할 때마다 한 번 function(substitution, [matches], longest_match_length)로 호출됩니다.

예제

다음 예는 readline 모듈의 히스토리 읽기와 쓰기 함수를 사용하여 사용자의 홈 디렉터리에서 .python_history라는 이름의 히스토리 파일을 자동으로 로드하고 저장하는 방법을 보여줍니다. 아래 코드는 일반적으로 사용자의 PYTHONSTARTUP 파일에서 대화식 세션 중에 자동으로 실행됩니다.

import atexit
import os
import readline

histfile = os.path.join(os.path.expanduser("~"), ".python_history")
try:
    readline.read_history_file(histfile)
    # default history len is -1 (infinite), which may grow unruly
    readline.set_history_length(1000)
except FileNotFoundError:
    pass

atexit.register(readline.write_history_file, histfile)

이 코드는 실제로 파이썬이 대화형 모드로 실행될 때 자동으로 실행됩니다 (Readline 구성을 참조하십시오).

다음 예는 같은 목표를 달성하지만 새 히스토리를 덧붙이기만 해서 동시적인(concurrent) 대화형 세션을 지원합니다.

import atexit
import os
import readline
histfile = os.path.join(os.path.expanduser("~"), ".python_history")

try:
    readline.read_history_file(histfile)
    h_len = readline.get_current_history_length()
except FileNotFoundError:
    open(histfile, 'wb').close()
    h_len = 0

def save(prev_h_len, histfile):
    new_h_len = readline.get_current_history_length()
    readline.set_history_length(1000)
    readline.append_history_file(new_h_len - prev_h_len, histfile)
atexit.register(save, h_len, histfile)

다음 예는 히스토리 저장/복원을 지원하도록 code.InteractiveConsole 클래스를 확장합니다.

import atexit
import code
import os
import readline

class HistoryConsole(code.InteractiveConsole):
    def __init__(self, locals=None, filename="<console>",
                 histfile=os.path.expanduser("~/.console-history")):
        code.InteractiveConsole.__init__(self, locals, filename)
        self.init_history(histfile)

    def init_history(self, histfile):
        readline.parse_and_bind("tab: complete")
        if hasattr(readline, "read_history_file"):
            try:
                readline.read_history_file(histfile)
            except FileNotFoundError:
                pass
            atexit.register(self.save_history, histfile)

    def save_history(self, histfile):
        readline.set_history_length(1000)
        readline.write_history_file(histfile)

rlcompleter — Completion function for GNU readline

소스 코드: Lib/rlcompleter.py [https://github.com/python/cpython/tree/main/Lib/rlcompleter.py]

The rlcompleter module defines a completion function suitable to be passed to set_completer() in the readline module.

When this module is imported on a Unix platform with the readline module available, an instance of the Completer class is automatically created and its complete() method is set as the readline completer. The method provides completion of valid Python identifiers and keywords.

예제:

>>> import rlcompleter
>>> import readline
>>> readline.parse_and_bind("tab: complete")
>>> readline. <TAB PRESSED>
readline.__doc__          readline.get_line_buffer(  readline.read_init_file(
readline.__file__         readline.insert_text(      readline.set_completer(
readline.__name__         readline.parse_and_bind(
>>> readline.

The rlcompleter module is designed for use with Python’s interactive mode. Unless Python is run with the -S option, the module is automatically imported and configured (see Readline 구성).

readline이 없는 플랫폼에서, 이 모듈이 정의하는 Completer 클래스는 여전히 사용자 정의 목적에 사용될 수 있습니다.

class rlcompleter.Completer

Completer 객체는 다음과 같은 메서드를 가집니다:

complete(text, state)

Return the next possible completion for text.

When called by the readline module, this method is called successively with state == 0, 1, 2, ... until the method returns None.

마침표('.')가 포함되지 않은 text로 호출되면, __main__, builtins 및 키워드(keyword 모듈에서 정의한 대로)에 현재 정의된 이름으로 완성됩니다.

If called for a dotted name, it will try to evaluate anything without obvious side-effects (functions will not be evaluated, but it can generate calls to __getattr__()) up to the last part, and find matches for the rest via the dir() function. Any exception raised during the evaluation of the expression is caught, silenced and None is returned.

바이너리 데이터 서비스

이 장에서 설명하는 모듈은 바이너리 데이터를 다루기 위한 기본 서비스 연산을 제공합니다. 파일 포맷, 네트워크 프로토콜과 관련 있는 바이너리 데이터에 대한 연산은 관련 절에서 설명합니다.

텍스트 처리 서비스에서 설명한 일부 라이브러리는 ASCII 호환 바이너리 형식 (예를 들면, re) 또는 모든 바이너리 데이터 (예를 들면, difflib)에 사용할 수 있습니다.

또한, 파이썬 내장 바이너리 데이터형에 대한 설명은 바이너리 시퀀스 형 — bytes, bytearray, memoryview 문서를 참고하세요.

struct — Interpret bytes as packed binary data

함수와 예외

error

pack()

pack_into()

unpack()

unpack_from()

iter_unpack()

calcsize()

포맷 문자열

바이트 순서, 크기 및 정렬

포맷 문자

예

Applications

Native Formats

Standard Formats

클래스

Struct

pack()

pack_into()

unpack()

unpack_from()

iter_unpack()

format

size

codecs — Codec registry and base classes

encode()

decode()

lookup()

CodecInfo

name

encode

decode

incrementalencoder

incrementaldecoder

streamwriter

streamreader

getencoder()

getdecoder()

getincrementalencoder()

getincrementaldecoder()

getreader()

getwriter()

register()

unregister()

open()

EncodedFile()

iterencode()

iterdecode()

BOM

BOM_BE

BOM_LE

BOM_UTF8

BOM_UTF16

BOM_UTF16_BE

BOM_UTF16_LE

BOM_UTF32

BOM_UTF32_BE

BOM_UTF32_LE

코덱 베이스 클래스

에러 처리기

register_error()

lookup_error()

strict_errors()

ignore_errors()

replace_errors()

backslashreplace_errors()

xmlcharrefreplace_errors()

namereplace_errors()

상태 없는 인코딩과 디코딩

Codec

encode()

decode()

증분 인코딩과 디코딩

IncrementalEncoder 객체

IncrementalEncoder

encode()

reset()

getstate()

setstate()

IncrementalDecoder 객체

IncrementalDecoder

decode()

reset()

getstate()

setstate()

스트림 인코딩과 디코딩

StreamWriter 객체

StreamWriter

write()

writelines()

reset()

StreamReader 객체

StreamReader

read()

readline()

readlines()

reset()

StreamReaderWriter 객체

StreamReaderWriter

StreamRecoder 객체

StreamRecoder

인코딩과 유니코드

표준 인코딩

파이썬 특정 인코딩

텍스트 인코딩

바이너리 변환

텍스트 변환

encodings.idna — 응용 프로그램에서의 국제화된 도메인 이름

nameprep()

ToASCII()

ToUnicode()

encodings.mbcs — 윈도우 ANSI 코드 페이지

encodings.utf_8_sig — BOM 서명이 있는 UTF-8 코덱

struct — Interpret bytes as packed binary data

소스 코드: Lib/struct.py [https://github.com/python/cpython/tree/main/Lib/struct.py]

This module converts between Python values and C structs represented as Python bytes objects. Compact format strings describe the intended conversions to/from Python values. The module’s functions and objects can be used for two largely distinct applications, data exchange with external sources (files or network connections), or data transfer between the Python application and the C layer.

참고

When no prefix character is given, native mode is the default. It packs or unpacks data based on the platform and compiler on which the Python interpreter was built. The result of packing a given C struct includes pad bytes which maintain proper alignment for the C types involved; similarly, alignment is taken into account when unpacking. In contrast, when communicating data between external sources, the programmer is responsible for defining byte ordering and padding between elements. See 바이트 순서, 크기 및 정렬 for details.

여러 struct 함수(그리고 Struct 의 메서드)는 buffer 인자를 취합니다. 이는 버퍼 프로토콜을 구현하고 읽을 수 있거나 읽고 쓸 수 있는 버퍼를 제공하는 객체를 나타냅니다. 이 목적으로 사용되는 가장 일반적인 형은 bytes와 bytearray지만, 바이트 배열로 볼 수 있는 많은 다른 형이 버퍼 프로토콜을 구현하므로, bytes 객체에서 추가로 복사하지 않고도 읽고 채울 수 있습니다.

함수와 예외

이 모듈은 다음과 같은 예외와 함수를 정의합니다:

exception struct.error

여러 상황에서 발생하는 예외; 인자는 무엇이 잘못되었는지 설명하는 문자열입니다.

struct.pack(format, v1, v2, ...)

v1, v2, … 값을 포함하고 포맷 문자열 format에 따라 패킹 된 바이트열 객체를 반환합니다. 인자는 포맷이 요구하는 값과 정확히 일치해야 합니다.

struct.pack_into(format, buffer, offset, v1, v2, ...)

포맷 문자열 format에 따라 값 v1, v2, … 를 패킹하고 패킹 된 바이트열을 쓰기 가능한 버퍼 buffer에 offset 위치에서부터 씁니다. offset은 필수 인자임에 유의하십시오.

struct.unpack(format, buffer)

포맷 문자열 format에 따라 버퍼 buffer(아마도 pack(format, ...)으로 패킹 된)에서 언 패킹 합니다. 정확히 하나의 항목을 포함하더라도 결과는 튜플입니다. 바이트 단위의 버퍼 크기는 (calcsize()에 의해 반영되는) 포맷이 요구하는 크기와 일치해야 합니다.

struct.unpack_from(format, /, buffer, offset=0)

포맷 문자열 format에 따라, offset 위치에서 시작하여 buffer에서 언 패킹 합니다. 정확히 하나의 항목을 포함하더라도 결과는 튜플입니다. offset 위치에서 시작하여 바이트 단위로 측정한 버퍼 크기는 (calcsize()에 의해 반영되는) 포맷이 요구하는 크기 이상이어야 합니다.

struct.iter_unpack(format, buffer)

Iteratively unpack from the buffer buffer according to the format string format. This function returns an iterator which will read equally sized chunks from the buffer until all its contents have been consumed. The buffer’s size in bytes must be a multiple of the size required by the format, as reflected by calcsize().

각 이터레이션은 포맷 문자열에 지정된 대로 튜플을 산출합니다.

Added in version 3.4.

struct.calcsize(format)

포맷 문자열 format에 해당하는 구조체(pack(format, ...)에 의해 생성되는 바이트열 객체)의 크기를 반환합니다.

포맷 문자열

Format strings describe the data layout when packing and unpacking data. They are built up from format characters, which specify the type of data being packed/unpacked. In addition, special characters control the byte order, size and alignment. Each format string consists of an optional prefix character which describes the overall properties of the data and one or more format characters which describe the actual data values and padding.

바이트 순서, 크기 및 정렬

By default, C types are represented in the machine’s native format and byte order, and properly aligned by skipping pad bytes if necessary (according to the rules used by the C compiler). This behavior is chosen so that the bytes of a packed struct correspond exactly to the memory layout of the corresponding C struct. Whether to use native byte ordering and padding or standard formats depends on the application.

또는, 다음 표에 따라, 포맷 문자열의 첫 번째 문자를 사용하여 패킹 된 데이터의 바이트 순서, 크기 및 정렬을 표시할 수 있습니다:

문자

바이트 순서

크기

정렬

@

네이티브

네이티브

네이티브

=

네이티브

표준

none

<

리틀 엔디안

표준

none

>

빅 엔디안

표준

none

!

네트워크 (= 빅 엔디안)

표준

none

첫 번째 문자가 이들 중 하나가 아니면, '@'로 가정합니다.

참고

The number 1023 (0x3ff in hexadecimal) has the following byte representations:

03 ff in big-endian (>)

ff 03 in little-endian (<)

Python example:

>>> import struct
>>> struct.pack('>h', 1023)
b'\x03\xff'
>>> struct.pack('<h', 1023)
b'\xff\x03'

Native byte order is big-endian or little-endian, depending on the host system. For example, Intel x86, AMD64 (x86-64), and Apple M1 are little-endian; IBM z and many legacy architectures are big-endian. Use sys.byteorder to check the endianness of your system.

네이티브 크기와 정렬은 C 컴파일러의 sizeof 표현식을 사용하여 결정됩니다. 이것은 항상 네이티브 바이트 순서와 결합합니다.

표준 크기는 포맷 문자에만 의존합니다; 포맷 문자 섹션의 표를 참조하십시오.

'@'과 '='의 차이점에 유의하십시오; 둘 다 네이티브 바이트 순서를 사용하지만, 후자는 크기와 정렬이 표준화됩니다.

'!' 형식은 IETF RFC 1700 [https://datatracker.ietf.org/doc/html/rfc1700]에 정의된 대로 항상 빅 엔디안인 네트워크 바이트 순서를 나타냅니다.

네이티브가 아닌 바이트 순서(강제 바이트 스와핑)를 표시하는 방법은 없습니다; '<'나 '>'를 적절히 선택하십시오.

노트:

패딩은 연속되는 구조체 멤버 간에만 자동으로 추가됩니다. 인코딩된 구조체의 시작이나 끝에는 패딩이 추가되지 않습니다.

네이티브가 아닌 크기와 정렬을 사용할 때는 패딩이 추가되지 않습니다, 예를 들어 ‘<’, ‘>’, ‘=’ 및 ‘!’ 에서.

구조체의 끝을 특정 형의 정렬 요구 사항에 맞추려면, 반복 횟수가 0인 해당 형의 코드로 포맷을 끝내십시오. 예를 참조하십시오.

포맷 문자

포맷 문자는 다음과 같은 의미가 있습니다; C와 파이썬 값 사이의 변환은 형을 주면 분명해야 합니다. ‘표준 크기’ 열은 표준 크기를 사용할 때 패킹 된 값의 크기를 바이트 단위로 나타냅니다; 즉, 포맷 문자열이 '<', '>', '!' 또는 '=' 중 하나로 시작하는 경우입니다. 네이티브 크기를 사용할 때, 패킹 된 값의 크기는 플랫폼에 따라 다릅니다.

포맷

C형

파이썬 형

표준 크기

노트

x

패드 바이트

값이 없습니다

(7)

c

char

길이가 1인 bytes

1

b

signed char

정수

1

(1), (2)

B

unsigned char

정수

1

(2)

?

_Bool

bool

1

(1)

h

short

정수

2

(2)

H

unsigned short

정수

2

(2)

i

int

정수

4

(2)

I

unsigned int

정수

4

(2)

l

long

정수

4

(2)

L

unsigned long

정수

4

(2)

q

long long

정수

8

(2)

Q

unsigned long long

정수

8

(2)

n

ssize_t

정수

(3)

N

size_t

정수

(3)

e

(6)

float

2

(4)

f

float

float

4

(4)

d

double

float

8

(4)

s

char[]

bytes

(9)

p

char[]

bytes

(8)

P

void*

정수

(5)

Additionally, if IEC 60559 compatible complex arithmetic (Annex G of the C11 standard) is supported, the following format characters are available:

포맷

C형

파이썬 형

표준 크기

노트

E

float complex

complex

8

(10)

C

double complex

complex

16

(10)

버전 3.3에서 변경: 'n'과 'N' 포맷에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: 'e' 포맷에 대한 지원이 추가되었습니다.

버전 3.14에서 변경: Added support for the 'E' and 'C' formats.

노트:

The '?' conversion code corresponds to the _Bool type defined by C standards since C99. In standard mode, it is represented by one byte.

When attempting to pack a non-integer using any of the integer conversion codes, if the non-integer has a __index__() method then that method is called to convert the argument to an integer before packing.

버전 3.2에서 변경: Added use of the __index__() method for non-integers.

'n'과 'N' 변환 코드는 (기본값이나 '@' 바이트 순서 문자로 선택된) 네이티브 크기에만 사용할 수 있습니다. 표준 크기의 경우, 응용 프로그램에 맞는 다른 정수 포맷을 사용할 수 있습니다.

'f', 'd' 및 'e' 변환 코드의 경우, 패킹 된 표현은 플랫폼에서 사용하는 부동 소수점 형식과 관계없이 IEEE 754 binary32, binary64 또는 binary16 형식을 사용합니다 (각각 'f', 'd' 또는 'e').

'P' 포맷 문자는 (기본값이나 '@' 바이트 순서 문자로 선택된) 네이티브 바이트 순서에만 사용할 수 있습니다. 바이트 순서 문자 '='는 호스트 시스템에 따라 리틀이나 빅 엔디안 순서를 사용하도록 선택합니다. struct 모듈은 이를 네이티브 순서로 해석하지 않아서, 'P' 형식을 사용할 수 없습니다.

IEEE 754 binary16 “반 정밀도” 형은 2008년 IEEE 754 표준 [https://en.wikipedia.org/wiki/IEEE_754-2008_revision] 개정판에서 도입되었습니다. 부호 비트, 5비트 지수 및 11비트 정밀도(10비트가 명시적으로 저장됩니다)를 가지며, 전체 정밀도에서 대략 6.1e-05와 6.5e+04 사이의 숫자를 나타낼 수 있습니다. 이 형은 C 컴파일러에서 널리 지원되지 않습니다: 일반적인 기계에서는, unsigned short를 저장에 사용할 수 있지만, 수학 연산에는 사용할 수 없습니다. 자세한 내용은 half-precision floating-point format [https://en.wikipedia.org/wiki/Half-precision_floating-point_format]의 Wikipedia 페이지를 참조하십시오.

When packing, 'x' inserts one NUL byte.

'p' 포맷 문자는 “파스칼 문자열”을 인코딩하는데, 이는 카운트에 의해 주어진 고정된 바이트 수에 저장된 짧은 가변 길이 문자열을 의미합니다. 저장된 첫 번째 바이트는 문자열의 길이나 255중 작은 값입니다. 문자열의 바이트가 그 뒤에 옵니다. pack()에 전달된 문자열이 너무 길면 (횟수 빼기 1보다 길면), 문자열의 선행 count-1 바이트만 저장됩니다. 문자열이 count-1보다 짧으면, 전부 정확한 바이트 수가 되도록 널 바이트로 채워집니다. unpack()의 경우, 'p' 포맷 문자는 count 바이트를 소비하지만, 반환된 문자열은 255바이트를 초과할 수 없음에 유의하십시오.

For the 's' format character, the count is interpreted as the length of the bytes, not a repeat count like for the other format characters; for example, '10s' means a single 10-byte string mapping to or from a single Python byte string, while '10c' means 10 separate one byte character elements (e.g., cccccccccc) mapping to or from ten different Python byte objects. (See 예 for a concrete demonstration of the difference.) If a count is not given, it defaults to 1. For packing, the string is truncated or padded with null bytes as appropriate to make it fit. For unpacking, the resulting bytes object always has exactly the specified number of bytes. As a special case, '0s' means a single, empty string (while '0c' means 0 characters).

For the 'E' and 'C' format characters, the packed representation uses the IEEE 754 binary32 and binary64 format for components of the complex number, regardless of the floating-point format used by the platform.

포맷 문자 앞에는 정수 반복 횟수가 올 수 있습니다. 예를 들어, 포맷 문자열 '4h'는 'hhhh'와 정확히 같습니다.

포맷 사이의 공백 문자는 무시됩니다; 횟수와 형식 사이에는 공백이 없어야 합니다.

정수 형식 ('b', 'B', 'h', 'H', 'i', 'I', 'l', 'L', 'q', 'Q') 중 하나를 사용하여 값 x를 패킹할 때, x가 해당 포맷의 유효한 범위를 벗어나면 struct.error가 발생합니다.

버전 3.1에서 변경: 이전에는, 일부 정수 포맷은 범위를 벗어난 값을 래핑하고 struct.error 대신 DeprecationWarning을 발생시켰습니다.

'?' 포맷 문자의 경우, 반환 값은 True나 False입니다. 패킹할 때, 인자 객체의 논리값이 사용됩니다. 네이티브나 표준 bool 표현에서 0이나 1이 패킹 되고, 언 패킹할 때 모든 0이 아닌 값은 True가 됩니다.

예

참고

Native byte order examples (designated by the '@' format prefix or lack of any prefix character) may not match what the reader’s machine produces as that depends on the platform and compiler.

Pack and unpack integers of three different sizes, using big endian ordering:

>>> from struct import *
>>> pack(">bhl", 1, 2, 3)
b'\x01\x00\x02\x00\x00\x00\x03'
>>> unpack('>bhl', b'\x01\x00\x02\x00\x00\x00\x03')
(1, 2, 3)
>>> calcsize('>bhl')
7

Attempt to pack an integer which is too large for the defined field:

>>> pack(">h", 99999)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
struct.error: 'h' format requires -32768 <= number <= 32767

Demonstrate the difference between 's' and 'c' format characters:

>>> pack("@ccc", b'1', b'2', b'3')
b'123'
>>> pack("@3s", b'123')
b'123'

언 패킹 된 필드는 변수에 대입하거나 결과를 네임드 튜플로 감싸서 이름을 붙일 수 있습니다:

>>> record = b'raymond   \x32\x12\x08\x01\x08'
>>> name, serialnum, school, gradelevel = unpack('<10sHHb', record)

>>> from collections import namedtuple
>>> Student = namedtuple('Student', 'name serialnum school gradelevel')
>>> Student._make(unpack('<10sHHb', record))
Student(name=b'raymond   ', serialnum=4658, school=264, gradelevel=8)

The ordering of format characters may have an impact on size in native mode since padding is implicit. In standard mode, the user is responsible for inserting any desired padding. Note in the first pack call below that three NUL bytes were added after the packed '#' to align the following integer on a four-byte boundary. In this example, the output was produced on a little endian machine:

>>> pack('@ci', b'#', 0x12131415)
b'#\x00\x00\x00\x15\x14\x13\x12'
>>> pack('@ic', 0x12131415, b'#')
b'\x15\x14\x13\x12#'
>>> calcsize('@ci')
8
>>> calcsize('@ic')
5

The following format 'llh0l' results in two pad bytes being added at the end, assuming the platform’s longs are aligned on 4-byte boundaries:

>>> pack('@llh0l', 1, 2, 3)
b'\x00\x00\x00\x01\x00\x00\x00\x02\x00\x03\x00\x00'

더 보기

모듈 array

동종 데이터의 패킹 된 바이너리 저장소.

Module json

JSON encoder and decoder.

Module pickle

Python object serialization.

Applications

Two main applications for the struct module exist, data interchange between Python and C code within an application or another application compiled using the same compiler (native formats), and data interchange between applications using agreed upon data layout (standard formats). Generally speaking, the format strings constructed for these two domains are distinct.

Native Formats

When constructing format strings which mimic native layouts, the compiler and machine architecture determine byte ordering and padding. In such cases, the @ format character should be used to specify native byte ordering and data sizes. Internal pad bytes are normally inserted automatically. It is possible that a zero-repeat format code will be needed at the end of a format string to round up to the correct byte boundary for proper alignment of consecutive chunks of data.

Consider these two simple examples (on a 64-bit, little-endian machine):

>>> calcsize('@lhl')
24
>>> calcsize('@llh')
18

Data is not padded to an 8-byte boundary at the end of the second format string without the use of extra padding. A zero-repeat format code solves that problem:

>>> calcsize('@llh0l')
24

The 'x' format code can be used to specify the repeat, but for native formats it is better to use a zero-repeat format like '0l'.

By default, native byte ordering and alignment is used, but it is better to be explicit and use the '@' prefix character.

Standard Formats

When exchanging data beyond your process such as networking or storage, be precise. Specify the exact byte order, size, and alignment. Do not assume they match the native order of a particular machine. For example, network byte order is big-endian, while many popular CPUs are little-endian. By defining this explicitly, the user need not care about the specifics of the platform their code is running on. The first character should typically be < or > (or !). Padding is the responsibility of the programmer. The zero-repeat format character won’t work. Instead, the user must explicitly add 'x' pad bytes where needed. Revisiting the examples from the previous section, we have:

>>> calcsize('<qh6xq')
24
>>> pack('<qh6xq', 1, 2, 3) == pack('@lhl', 1, 2, 3)
True
>>> calcsize('@llh')
18
>>> pack('@llh', 1, 2, 3) == pack('<qqh', 1, 2, 3)
True
>>> calcsize('<qqh6x')
24
>>> calcsize('@llh0l')
24
>>> pack('@llh0l', 1, 2, 3) == pack('<qqh6x', 1, 2, 3)
True

The above results (executed on a 64-bit machine) aren’t guaranteed to match when executed on different machines. For example, the examples below were executed on a 32-bit machine:

>>> calcsize('<qqh6x')
24
>>> calcsize('@llh0l')
12
>>> pack('@llh0l', 1, 2, 3) == pack('<qqh6x', 1, 2, 3)
False

클래스

struct 모듈은 또한 다음 형을 정의합니다:

class struct.Struct(format)

Return a new Struct object which writes and reads binary data according to the format string format. Creating a Struct object once and calling its methods is more efficient than calling module-level functions with the same format since the format string is only compiled once.

참고

The compiled versions of the most recent format strings passed to the module-level functions are cached, so programs that use only a few format strings needn’t worry about reusing a single Struct instance.

컴파일된 Struct 객체는 다음 메서드와 어트리뷰트를 지원합니다:

pack(v1, v2, ...)

pack() 함수와 동일하고, 컴파일된 포맷을 사용합니다. (len(result)는 size와 같게 됩니다.)

pack_into(buffer, offset, v1, v2, ...)

pack_into() 함수와 동일하고, 컴파일된 포맷을 사용합니다.

unpack(buffer)

unpack() 함수와 동일하고, 컴파일된 포맷을 사용합니다. 바이트 단위의 버퍼 크기는 size와 같아야 합니다.

unpack_from(buffer, offset=0)

unpack_from() 함수와 동일하고, 컴파일된 포맷을 사용합니다. offset 위치에서 시작하는 바이트 단위의 버퍼 크기는 size 이상이어야 합니다.

iter_unpack(buffer)

iter_unpack() 함수와 동일하고, 컴파일된 포맷을 사용합니다. 바이트 단위의 버퍼 크기는 size의 배수이어야 합니다.

Added in version 3.4.

format

이 Struct 객체를 구성하는 데 사용된 포맷 문자열.

버전 3.7에서 변경: 포맷 문자열형은 이제 bytes 대신 str입니다.

size

format에 해당하는 구조체(pack() 메서드에 의해 생성된 바이트열 객체)의 계산된 크기.

버전 3.13에서 변경: The repr() of structs has changed. It is now:

>>> Struct('i')
Struct('i')

codecs — Codec registry and base classes

소스 코드: Lib/codecs.py [https://github.com/python/cpython/tree/main/Lib/codecs.py]

This module defines base classes for standard Python codecs (encoders and decoders) and provides access to the internal Python codec registry, which manages the codec and error handling lookup process. Most standard codecs are text encodings, which encode text to bytes (and decode bytes to text), but there are also codecs provided that encode text to text, and bytes to bytes. Custom codecs may encode and decode between arbitrary types, but some module features are restricted to be used specifically with text encodings or with codecs that encode to bytes.

이 모듈은 임의의 코덱으로 인코딩과 디코딩하는 다음 함수를 정의합니다:

codecs.encode(obj, encoding='utf-8', errors='strict')

encoding을 위해 등록된 코덱을 사용하여 obj를 인코딩합니다.

원하는 에러 처리 방식을 설정하기 위해 errors가 주어질 수 있습니다. 기본 에러 처리기는 'strict'이며 인코딩 에러가 ValueError(또는 UnicodeEncodeError 와 같은 더 많은 코덱 관련 서브 클래스)를 발생시킨다는 뜻입니다. 코덱 에러 처리에 대한 자세한 내용은 코덱 베이스 클래스를 참조하십시오.

codecs.decode(obj, encoding='utf-8', errors='strict')

encoding을 위해 등록된 코덱을 사용하여 obj를 디코딩합니다.

원하는 에러 처리 방식을 설정하기 위해 errors가 주어질 수 있습니다. 기본 에러 처리기는 'strict'이며 디코딩 에러가 ValueError (또는 UnicodeDecodeError 와 같은 더 많은 코덱 관련 서브 클래스)를 발생시킨다는 뜻입니다. 코덱 에러 처리에 대한 자세한 내용은 코덱 베이스 클래스를 참조하십시오.

각 코덱에 대한 자세한 내용도 직접 확인할 수 있습니다:

codecs.lookup(encoding)

파이썬 코덱 레지스트리에서 코덱 정보를 조회하고 아래 정의된 CodecInfo 객체를 반환합니다.

인코딩은 먼저 레지스트리 캐시에서 조회됩니다. 찾을 수 없으면, 등록된 검색 함수 리스트를 탐색합니다. CodecInfo 객체가 없으면, LookupError가 발생합니다. 그렇지 않으면, CodecInfo 객체가 캐시에 저장되고 호출자에게 반환됩니다.

class codecs.CodecInfo(encode, decode, streamreader=None, streamwriter=None, incrementalencoder=None, incrementaldecoder=None, name=None)

코덱 레지스트리를 조회할 때의 코덱 세부 정보. 생성자 인자는 같은 이름의 어트리뷰트에 저장됩니다:

name

인코딩의 이름.

encode

decode

상태 없는 인코딩과 디코딩 함수. 이들은 코덱 인스턴스의 encode()와 decode() 메서드와 같은 인터페이스를 갖는 함수나 메서드여야 합니다 (코덱 인터페이스를 참조하십시오). 함수나 메서드는 상태 없는 모드로 작동할 것으로 기대됩니다.

incrementalencoder

incrementaldecoder

증분형 인코더와 디코더 클래스 또는 팩토리 함수. 이들은 각각 베이스 클래스 IncrementalEncoder와 IncrementalDecoder가 정의하는 인터페이스를 제공해야 합니다. 증분 코덱은 상태를 유지할 수 있습니다.

streamwriter

streamreader

스트림 기록기와 판독기 클래스 또는 팩토리 함수. 이들은 각각 베이스 클래스 StreamWriter와 StreamReader가 정의하는 인터페이스를 제공해야 합니다. 스트림 코덱은 상태를 유지할 수 있습니다.

다양한 코덱 구성 요소에 대한 액세스를 단순화하기 위해, 이 모듈은 코덱 조회에 lookup()을 사용하는 다음과 같은 추가 함수를 제공합니다:

codecs.getencoder(encoding)

주어진 인코딩에 대한 코덱을 찾아서 해당 인코더 함수를 반환합니다.

인코딩을 찾을 수 없는 경우 LookupError를 발생시킵니다.

codecs.getdecoder(encoding)

주어진 인코딩에 대한 코덱을 찾아서 해당 디코더 함수를 반환합니다.

인코딩을 찾을 수 없는 경우 LookupError를 발생시킵니다.

codecs.getincrementalencoder(encoding)

주어진 인코딩에 대한 코덱을 찾아서 증분 인코더 클래스나 팩토리 함수를 반환합니다.

인코딩을 찾을 수 없거나 코덱이 증분 인코더를 지원하지 않는 경우 LookupError를 발생시킵니다.

codecs.getincrementaldecoder(encoding)

주어진 인코딩에 대한 코덱을 찾아서 증분 디코더 클래스나 팩토리 함수를 반환합니다.

인코딩을 찾을 수 없거나 코덱이 증분 디코더를 지원하지 않는 경우 LookupError를 발생시킵니다.

codecs.getreader(encoding)

주어진 인코딩의 코덱을 찾아서 StreamReader 클래스나 팩토리 함수를 반환합니다.

인코딩을 찾을 수 없는 경우 LookupError를 발생시킵니다.

codecs.getwriter(encoding)

주어진 인코딩의 코덱을 찾아서 StreamWriter 클래스나 팩토리 함수를 반환합니다.

인코딩을 찾을 수 없는 경우 LookupError를 발생시킵니다.

적합한 코덱 검색 함수를 등록하여 사용자 정의 코덱을 사용할 수 있도록 합니다:

codecs.register(search_function)

Register a codec search function. Search functions are expected to take one argument, being the encoding name in all lower case letters with hyphens and spaces converted to underscores, and return a CodecInfo object. In case a search function cannot find a given encoding, it should return None.

버전 3.9에서 변경: Hyphens and spaces are converted to underscore.

codecs.unregister(search_function)

Unregister a codec search function and clear the registry’s cache. If the search function is not registered, do nothing.

Added in version 3.10.

내장 open()과 관련 io 모듈은 인코딩된 텍스트 파일 작업에 권장되는 접근 방법이지만, 이 모듈은 바이너리 파일로 작업할 때 더 넓은 범위의 코덱을 사용할 수 있도록 하는 추가 유틸리티 함수와 클래스를 제공합니다:

codecs.open(filename, mode='r', encoding=None, errors='strict', buffering=-1)

주어진 mode를 사용하여 인코딩된 파일을 열고 투명한 인코딩/디코딩을 제공하는 StreamReaderWriter 의 인스턴스를 반환합니다. 기본 파일 모드는 'r'이고, 파일을 읽기 모드로 연다는 뜻입니다.

참고

If encoding is not None, then the underlying encoded files are always opened in binary mode. No automatic conversion of '\n' is done on reading and writing. The mode argument may be any binary mode acceptable to the built-in open() function; the 'b' is automatically added.

encoding은 파일에 사용될 인코딩을 지정합니다. 바이트열에서 인코딩하고 바이트열로 디코딩하는 모든 인코딩이 허용되며, 파일 메서드가 지원하는 데이터형은 사용된 코덱에 따라 다릅니다.

에러 처리를 정의하기 위해 errors가 제공될 수 있습니다. 기본값은 'strict'이고 인코딩 에러가 발생하면 ValueError가 발생합니다.

buffering은 내장 open() 함수에서와 같은 의미입니다. 기본값은 -1이며 기본 버퍼 크기가 사용됨을 의미합니다.

버전 3.11에서 변경: The 'U' mode has been removed.

codecs.EncodedFile(file, data_encoding, file_encoding=None, errors='strict')

투명한 트랜스코딩을 제공하는 file의 래핑 된 버전인 StreamRecoder 인스턴스를 반환합니다. 래핑 된 버전이 닫힐 때 원본 파일이 닫힙니다.

래핑 된 파일에 기록된 데이터는 주어진 data_encoding에 따라 디코딩된 다음 file_encoding을 사용하여 바이트열로 원본 파일에 기록됩니다. 원본 파일에서 읽은 바이트열은 file_encoding에 따라 디코딩되며, 결과는 data_encoding을 사용하여 인코딩됩니다.

file_encoding이 제공되지 않으면, 기본값은 data_encoding입니다.

에러 처리를 정의하기 위해 errors가 제공될 수 있습니다. 기본값은 'strict'이며, 인코딩 에러가 발생하면 ValueError가 발생합니다.

codecs.iterencode(iterator, encoding, errors='strict', **kwargs)

증분 인코더를 사용하여 iterator에서 제공하는 입력을 반복적으로 인코딩합니다. 이 함수는 제너레이터입니다. errors 인자(다른 키워드 인자뿐만 아니라)는 증분 인코더로 전달됩니다.

이 함수를 사용하려면 코덱에서 인코딩할 텍스트 str 객체를 허용해야 합니다. 따라서 base64_codec과 같은 바이트열-바이트열 인코더는 지원하지 않습니다.

codecs.iterdecode(iterator, encoding, errors='strict', **kwargs)

증분 디코더를 사용하여 iterator에서 제공하는 입력을 반복적으로 디코딩합니다. 이 함수는 제너레이터입니다. errors 인자(다른 키워드 인자뿐만 아니라)는 증분 디코더로 전달됩니다.

이 함수를 사용하려면 코덱에서 디코딩할 bytes 객체를 허용해야 합니다. 따라서 rot_13이 iterencode()로 동등하게 사용될 수 있지만, rot_13과 같은 텍스트-텍스트 인코더는 지원하지 않습니다.

이 모듈은 또한 플랫폼 종속 파일을 읽고 쓰는 데 유용한 다음 상수를 제공합니다:

codecs.BOM

codecs.BOM_BE

codecs.BOM_LE

codecs.BOM_UTF8

codecs.BOM_UTF16

codecs.BOM_UTF16_BE

codecs.BOM_UTF16_LE

codecs.BOM_UTF32

codecs.BOM_UTF32_BE

codecs.BOM_UTF32_LE

이 상수는 여러 인코딩에서 유니코드 바이트 순서 표시(BOM)인 다양한 바이트 시퀀스를 정의합니다. UTF-16과 UTF-32 데이터 스트림에서 사용된 바이트 순서를 나타내는 데 사용되며, UTF-8에서 유니코드 서명으로 사용됩니다. BOM_UTF16은 플랫폼의 네이티브 바이트 순서에 따라 BOM_UTF16_BE나 BOM_UTF16_LE이며, BOM은 BOM_UTF16의 별칭, BOM_LE는 BOM_UTF16_LE의 별칭, BOM_BE는 BOM_UTF16_BE의 별칭입니다. 다른 것은 UTF-8과 UTF-32 인코딩에서 BOM을 나타냅니다.

코덱 베이스 클래스

codecs 모듈은 코덱 객체로 작업하기 위한 인터페이스를 정의하는 베이스 클래스 집합을 정의하며, 사용자 정의 코덱 구현의 기초로 사용될 수도 있습니다.

각 코덱은 파이썬에서 코덱으로 사용할 수 있도록 네 가지 인터페이스를 정의해야 합니다: 상태 없는 인코더, 상태 없는 디코더, 스트림 판독기 및 스트림 기록기. 스트림 판독기와 기록기는 일반적으로 상태 없는 인코더/디코더를 재사용하여 파일 프로토콜을 구현합니다. 코덱 작성자는 코덱에서 인코딩과 디코딩 에러를 처리하는 방법도 정의해야 합니다.

에러 처리기

To simplify and standardize error handling, codecs may implement different error handling schemes by accepting the errors string argument:

>>> 'German ß, ♬'.encode(encoding='ascii', errors='backslashreplace')
b'German \\xdf, \\u266c'
>>> 'German ß, ♬'.encode(encoding='ascii', errors='xmlcharrefreplace')
b'German &#223;, &#9836;'

The following error handlers can be used with all Python 표준 인코딩 codecs:

값

의미

'strict'

Raise UnicodeError (or a subclass), this is the default. Implemented in strict_errors().

'ignore'

잘못된 데이터를 무시하고 추가 통지 없이 계속 진행합니다. ignore_errors()에서 구현되었습니다.

'replace'

Replace with a replacement marker. On encoding, use ? (ASCII character). On decoding, use � (U+FFFD, the official REPLACEMENT CHARACTER). Implemented in replace_errors().

'backslashreplace'

Replace with backslashed escape sequences. On encoding, use hexadecimal form of Unicode code point with formats \xhh \uxxxx \Uxxxxxxxx. On decoding, use hexadecimal form of byte value with format \xhh. Implemented in backslashreplace_errors().

'surrogateescape'

디코딩 시, 바이트를 U+DC80에서 U+DCFF 범위의 개별 서로게이트 코드(surrogate code)로 바꿉니다. 이 코드는 데이터를 인코딩할 때 'surrogateescape' 에러 처리기가 사용되면 같은 바이트로 다시 변환됩니다. (자세한 내용은 PEP 383 [https://peps.python.org/pep-0383/]을 참조하십시오.)

The following error handlers are only applicable to encoding (within text encodings):

값

의미

'xmlcharrefreplace'

Replace with XML/HTML numeric character reference, which is a decimal form of Unicode code point with format &#num;. Implemented in xmlcharrefreplace_errors().

'namereplace'

Replace with \N{...} escape sequences, what appears in the braces is the Name property from Unicode Character Database. Implemented in namereplace_errors().

또한, 다음 에러 처리기는 지정된 코덱에만 적용됩니다:

값

코덱

의미

'surrogatepass'

utf-8, utf-16, utf-32, utf-16-be, utf-16-le, utf-32-be, utf-32-le

Allow encoding and decoding surrogate code point (U+D800 - U+DFFF) as normal code point. Otherwise these codecs treat the presence of surrogate code point in str as an error.

Added in version 3.1: 'surrogateescape'와 'surrogatepass' 에러 처리기.

버전 3.4에서 변경: The 'surrogatepass' error handler now works with utf-16* and utf-32* codecs.

Added in version 3.5: 'namereplace' 에러 처리기.

버전 3.5에서 변경: The 'backslashreplace' error handler now works with decoding and translating.

새 이름으로 에러 처리기를 등록하여 허용되는 값 집합을 확장할 수 있습니다:

codecs.register_error(name, error_handler)

에러 처리 함수 error_handler를 name이라는 이름으로 등록합니다. error_handler 인자는 name이 errors 매개 변수로 지정될 때, 인코딩과 디코딩 중에 에러가 있으면 호출됩니다.

인코딩의 경우, 에러 위치에 대한 정보가 포함된 UnicodeEncodeError 인스턴스와 함께 error_handler가 호출됩니다. 에러 처리기는 이 예외나 다른 예외를 발생시키거나, 입력의 인코딩할 수 없는 부분의 대체 값과 인코딩을 계속할 위치를 담은 튜플을 반환해야 합니다. 대체 값은 str이나 bytes일 수 있습니다. 대체 값이 바이트열이면, 인코더는 이를 단순히 출력 버퍼에 복사합니다. 대체 값이 문자열이면, 인코더는 대체 값을 인코딩합니다. 지정된 위치에서 원래 입력으로 인코딩이 계속됩니다. 음수 위칫값은 입력 문자열의 끝을 기준으로 처리됩니다. 결과 위치가 범위를 벗어나면 IndexError가 발생합니다.

UnicodeDecodeError 나 UnicodeTranslateError 가 처리기로 전달되고 에러 처리기의 대체 값을 출력에 직접 넣는다는 점을 제외하면, 디코딩과 변환(translating)은 비슷하게 작동합니다.

이전에 등록된 에러 처리기(표준 에러 처리기를 포함하여)는 이름으로 조회할 수 있습니다:

codecs.lookup_error(name)

name이라는 이름으로 이전에 등록된 에러 처리기를 반환합니다.

처리기를 찾을 수 없으면 LookupError를 발생시킵니다.

다음과 같은 표준 에러 처리기가 모듈 수준 함수로 제공됩니다:

codecs.strict_errors(exception)

Implements the 'strict' error handling.

Each encoding or decoding error raises a UnicodeError.

codecs.ignore_errors(exception)

Implements the 'ignore' error handling.

Malformed data is ignored; encoding or decoding is continued without further notice.

codecs.replace_errors(exception)

Implements the 'replace' error handling.

Substitutes ? (ASCII character) for encoding errors or � (U+FFFD, the official REPLACEMENT CHARACTER) for decoding errors.

codecs.backslashreplace_errors(exception)

Implements the 'backslashreplace' error handling.

Malformed data is replaced by a backslashed escape sequence. On encoding, use the hexadecimal form of Unicode code point with formats \xhh \uxxxx \Uxxxxxxxx. On decoding, use the hexadecimal form of byte value with format \xhh.

버전 3.5에서 변경: Works with decoding and translating.

codecs.xmlcharrefreplace_errors(exception)

Implements the 'xmlcharrefreplace' error handling (for encoding within text encoding only).

The unencodable character is replaced by an appropriate XML/HTML numeric character reference, which is a decimal form of Unicode code point with format &#num; .

codecs.namereplace_errors(exception)

Implements the 'namereplace' error handling (for encoding within text encoding only).

The unencodable character is replaced by a \N{...} escape sequence. The set of characters that appear in the braces is the Name property from Unicode Character Database. For example, the German lowercase letter 'ß' will be converted to byte sequence \N{LATIN SMALL LETTER SHARP S} .

Added in version 3.5.

상태 없는 인코딩과 디코딩

기본 Codec 클래스는 다음과 같은 메서드를 정의하는데, 상태 없는 인코더와 디코더의 함수 인터페이스를 정의하기도 합니다:

class codecs.Codec

encode(input, errors='strict')

객체 input을 인코딩하고 튜플(출력 객체, 소비한 길이)을 반환합니다. 예를 들어, 텍스트 인코딩은 특정 문자 집합 인코딩 (예를 들어, cp1252나 iso-8859-1)을 사용하여 문자열 객체를 바이트열 객체로 변환합니다.

errors 인자는 적용할 에러 처리를 정의합니다. 기본값은 'strict' 처리입니다.

이 메서드는 Codec 인스턴스에 상태를 저장하지 않을 수 있습니다. 인코딩 효율을 높이기 위해 상태를 유지해야 하는 코덱에서는 StreamWriter를 사용하십시오.

인코더는 길이가 0인 입력을 처리하고 이 상황에서는 출력 객체 형의 빈 객체를 반환할 수 있어야 합니다.

decode(input, errors='strict')

객체 input을 디코딩하고 튜플 (출력 객체, 소비한 길이)를 반환합니다. 예를 들어, 텍스트 인코딩의 경우, 디코딩은 특정 문자 집합 인코딩을 사용하여 인코딩된 바이트열 객체를 문자열 객체로 변환합니다.

텍스트 인코딩과 바이트열-바이트열 코덱의 경우, input은 바이트열 객체이거나 읽기 전용 버퍼 인터페이스를 제공하는 객체여야 합니다 – 예를 들어, 버퍼 객체와 및 메모리 맵핑 파일.

errors 인자는 적용할 에러 처리를 정의합니다. 기본값은 'strict' 처리입니다.

이 메서드는 Codec 인스턴스에 상태를 저장하지 않을 수 있습니다. 디코딩 효율을 높이기 위해 상태를 유지해야 하는 코덱에서는 StreamReader를 사용하십시오.

디코더는 길이가 0인 입력을 처리하고 이 상황에서 출력 객체 형의 빈 객체를 반환할 수 있어야 합니다.

증분 인코딩과 디코딩

IncrementalEncoder와 IncrementalDecoder 클래스는 증분 인코딩과 디코딩을 위한 기본 인터페이스를 제공합니다. 입력을 인코딩/디코딩하는 것이 상태 없는 인코더/디코더 함수를 한 번 호출하는 것이 아니라, 증분 인코더/디코더의 encode()/decode() 메서드를 여러 번 호출하여 수행됩니다. 증분 인코더/디코더는 메서드 호출 중에 인코딩/디코딩 프로세스를 추적합니다.

encode()/decode() 메서드에 대한 호출의 연결된 출력은 모든 단일 입력을 하나로 결합하여 상태 없는 인코더/디코더로 인코딩/디코딩되는 것과 같습니다.

IncrementalEncoder 객체

IncrementalEncoder 클래스는 여러 단계로 입력을 인코딩하는 데 사용됩니다. 파이썬 코덱 레지스트리와 호환되도록 모든 증분 인코더가 정의해야 하는 다음 메서드를 정의합니다.

class codecs.IncrementalEncoder(errors='strict')

IncrementalEncoder 인스턴스의 생성자.

모든 증분 인코더는 이 생성자 인터페이스를 제공해야 합니다. 추가 키워드 인자를 자유롭게 추가할 수 있지만, 여기에 정의된 키워드 인자만 파이썬 코덱 레지스트리에서 사용됩니다.

IncrementalEncoder는 errors 키워드 인자를 제공하여 다른 에러 처리 체계를 구현할 수 있습니다. 가능한 값은 에러 처리기를 참조하십시오.

errors 인자는 같은 이름의 어트리뷰트에 대입됩니다. 이 어트리뷰트에 대입하면 IncrementalEncoder 객체의 수명 동안 다른 에러 처리 전략 간에 전환할 수 있습니다.

encode(object, final=False)

object를 (인코더의 현재 상태를 고려하여) 인코딩하고 결과 인코딩된 객체를 반환합니다. 이것이 encode()에 대한 마지막 호출이면 final은 참이어야 합니다 (기본값은 거짓).

reset()

인코더를 초기 상태로 재설정합니다. 출력은 버려집니다: 인코더를 재설정하고 출력을 얻으려면, 필요하면 빈 바이트열이나 텍스트 문자열을 전달하여, .encode(object, final=True)를 호출하십시오.

getstate()

인코더의 현재 상태를 반환하는데, 정수여야 합니다. 구현은 0이 가장 흔한 상태가 되도록 해야 합니다. (정수보다 복잡한 상태는 상태를 마샬링/피클링하고 결과 문자열의 바이트열을 정수로 인코딩하여 정수로 변환할 수 있습니다.)

setstate(state)

인코더 상태를 state로 설정합니다. state는 getstate()가 반환한 인코더 상태여야 합니다.

IncrementalDecoder 객체

IncrementalDecoder 클래스는 여러 단계로 입력을 디코딩하는 데 사용됩니다. 파이썬 코덱 레지스트리와 호환되도록 모든 증분 디코더에서 정의해야 하는 다음 메서드를 정의합니다.

class codecs.IncrementalDecoder(errors='strict')

IncrementalDecoder 인스턴스의 생성자.

모든 증분 디코더는 이 생성자 인터페이스를 제공해야 합니다. 추가 키워드 인자를 자유롭게 추가할 수 있지만, 여기에 정의된 키워드 인자만 파이썬 코덱 레지스트리에서 사용됩니다.

IncrementalDecoder는 errors 키워드 인자를 제공하여 다른 에러 처리 체계를 구현할 수 있습니다. 가능한 값은 에러 처리기를 참조하십시오.

errors 인자는 같은 이름의 어트리뷰트에 대입됩니다. 이 어트리뷰트에 대입하면 IncrementalDecoder 객체의 수명 동안 다른 에러 처리 전략 간에 전환할 수 있습니다.

decode(object, final=False)

object를 디코딩하고 (디코더의 현재 상태를 고려하여) 결과 디코딩된 객체를 반환합니다. 이것이 decode()에 대한 마지막 호출이면 final은 참이어야 합니다 (기본값은 거짓). final이 참이면 디코더는 입력을 완전히 디코딩해야 하며 모든 버퍼를 플러시 해야 합니다. 이것이 가능하지 않으면 (예를 들어 입력 끝의 불완전한 바이트 시퀀스로 인해), 상태 없는 경우와 같이 에러 처리를 시작해야 합니다 (예외가 발생시킬 수 있습니다).

reset()

디코더를 초기 상태로 재설정합니다.

getstate()

디코더의 현재 상태를 반환합니다. 두 항목이 있는 튜플이어야 하며, 첫 번째는 여전히 디코딩되지 않은 입력을 포함하는 버퍼여야 합니다. 두 번째는 정수여야 하며 추가 상태 정보일 수 있습니다. (구현은 0이 가장 흔한 추가 상태 정보가 되도록 해야 합니다.) 이 추가 상태 정보가 0이면, 입력 버퍼가 없고 추가 상태 정보가 0인 상태로 디코더를 설정할 수 있어서, 이전에 버퍼링 된 입력을 디코더에 공급하면 출력을 생성하지 않고 이전 상태로 되돌아갈 수 있어야 합니다. (정수보다 복잡한 추가 상태 정보는 정보를 마샬링/피클링하고 결과 문자열의 바이트를 정수로 인코딩하여 정수로 변환할 수 있습니다.)

setstate(state)

디코더의 상태를 state로 설정합니다. state는 getstate()가 반환한 디코더 상태여야 합니다.

스트림 인코딩과 디코딩

The StreamWriter and StreamReader classes provide generic working interfaces which can be used to implement new encoding submodules very easily. See encodings.utf_8 for an example of how this is done.

StreamWriter 객체

StreamWriter 클래스는 Codec의 서브 클래스이며 파이썬 코덱 레지스트리와 호환되도록 모든 스트림 기록기가 정의해야 하는 다음 메서드를 정의합니다.

class codecs.StreamWriter(stream, errors='strict')

StreamWriter 인스턴스의 생성자.

모든 스트림 기록기는 이 생성자 인터페이스를 제공해야 합니다. 추가 키워드 인자를 자유롭게 추가할 수 있지만, 여기에 정의된 키워드 인자만 파이썬 코덱 레지스트리에서 사용됩니다.

stream 인자는 특정 코덱에 적합하도록 텍스트나 바이너리 데이터를 쓰기 위해 열린 파일류 객체여야 합니다.

StreamWriter는 errors 키워드 인자를 제공하여 다른 에러 처리 체계를 구현할 수 있습니다. 하부 스트림 코덱이 지원할 수 있는 표준 에러 처리기에 대해서는 에러 처리기를 참조하십시오.

errors 인자는 같은 이름의 어트리뷰트에 대입됩니다. 이 어트리뷰트에 대입하면 StreamWriter 객체의 수명 동안 다른 에러 처리 전략 간에 전환할 수 있습니다.

write(object)

스트림에 인코딩된 객체의 내용을 씁니다.

writelines(list)

Writes the concatenated iterable of strings to the stream (possibly by reusing the write() method). Infinite or very large iterables are not supported. The standard bytes-to-bytes codecs do not support this method.

reset()

내부 상태를 유지하는 데 사용되는 코덱 버퍼를 재설정합니다.

이 메서드를 호출하면 출력의 데이터가 깨끗한 상태가 되어 상태를 복구하기 위해 전체 스트림을 다시 스캔하지 않고도 새로운 최신 데이터를 추가할 수 있도록 합니다.

위의 메서드 외에도, StreamWriter는 하부 스트림에서 온 다른 모든 메서드와 어트리뷰트를 상속해야 합니다.

StreamReader 객체

StreamReader 클래스는 Codec의 서브 클래스이며 파이썬 코덱 레지스트리와 호환되도록 모든 스트림 판독기가 정의해야 하는 다음 메서드를 정의합니다.

class codecs.StreamReader(stream, errors='strict')

StreamReader 인스턴스의 생성자.

모든 스트림 판독기는 이 생성자 인터페이스를 제공해야 합니다. 추가 키워드 인자를 자유롭게 추가할 수 있지만, 여기에 정의된 키워드 인자만 파이썬 코덱 레지스트리에서 사용됩니다.

stream 인자는 특정 코덱에 적합하게 텍스트나 바이너리 데이터를 읽기 위해 열린 파일류 객체여야 합니다.

StreamReader는 errors 키워드 인자를 제공하여 다른 에러 처리 체계를 구현할 수 있습니다. 하부 스트림 코덱이 지원할 수 있는 표준 에러 처리기에 대해서는 에러 처리기를 참조하십시오.

errors 인자는 같은 이름의 어트리뷰트에 대입됩니다. 이 어트리뷰트에 대입하면 StreamReader 객체의 수명 동안 다른 에러 처리 전략 간에 전환할 수 있습니다.

errors 인자에 허용되는 값 집합은 register_error()로 확장될 수 있습니다.

read(size=-1, chars=-1, firstline=False)

스트림에서 데이터를 디코딩하고 결과 객체를 반환합니다.

chars 인자는 반환할 디코딩 된 코드 포인트나 바이트의 수를 나타냅니다. read() 메서드는 요청된 것보다 더 많은 데이터를 반환하지 않지만, 사용 가능한 것이 충분하지 않으면 더 적게 반환할 수 있습니다.

size 인자는 디코딩을 위해 읽을 인코딩 된 바이트나 코드 포인트의 대략적인 최대 수를 나타냅니다. 디코더는 이 설정을 적절하게 수정할 수 있습니다. 기본값 -1은 가능한 한 많이 읽고 디코딩함을 나타냅니다. 이 매개 변수는 커다란 파일을 한 번에 디코딩하지 않도록 하기 위한 것입니다.

firstline 플래그는 이후 줄에 디코딩 에러가 있으면 첫 번째 줄만 반환해도 충분함을 나타냅니다.

이 메서드는 탐욕스러운(greedy) 읽기 전략을 사용해야 합니다. 즉, 인코딩 정의와 주어진 size 내에서 허용되는 만큼 많은 데이터를 읽어야 합니다. 예를 들어 스트림에 선택적 인코딩 종료나 상태 마커가 있으면, 이것도 읽어야 합니다.

readline(size=None, keepends=True)

입력 스트림에서 한 줄을 읽고 디코딩된 데이터를 반환합니다.

주어지면, size는 스트림의 read() 메서드에 size 인자로 전달됩니다.

keepends가 거짓이면 줄 종료가 반환된 줄에서 제거됩니다.

readlines(sizehint=None, keepends=True)

입력 스트림에서 사용 가능한 모든 줄을 읽고 줄의 리스트로 반환합니다.

줄 종료는 코덱의 decode() 메서드를 사용하여 구현되며 keepends가 참이면 리스트 항목에 포함됩니다.

주어지면, sizehint는 스트림의 read() 메서드에 size 인자로 전달됩니다.

reset()

내부 상태를 유지하는 데 사용되는 코덱 버퍼를 재설정합니다.

스트림 위치 변경이 발생하지 않아야 함에 유의하십시오. 이 메서드는 주로 디코딩 에러에서 복구할 수 있도록 하기 위한 것입니다.

위의 메서드 외에도 StreamReader는 하부 스트림에서 다른 모든 메서드와 어트리뷰트를 상속해야 합니다.

StreamReaderWriter 객체

StreamReaderWriter 는 읽기와 쓰기 모드 모두에서 작동하는 스트림을 래핑하도록 하는 편의 클래스입니다.

lookup() 함수가 반환한 팩토리 함수를 사용하여 인스턴스를 구성할 수 있도록 설계되었습니다.

class codecs.StreamReaderWriter(stream, Reader, Writer, errors='strict')

StreamReaderWriter 인스턴스를 만듭니다. stream은 파일류 객체여야 합니다. Reader와 Writer는 각각 StreamReader와 StreamWriter 인터페이스를 제공하는 팩토리 함수나 클래스여야 합니다. 에러 처리는 스트림 판독기와 기록기에 정의된 것과 같은 방식으로 수행됩니다.

StreamReaderWriter 인스턴스는 StreamReader와 StreamWriter 클래스가 결합한 인터페이스를 정의합니다. 하부 스트림에서 다른 모든 메서드와 어트리뷰트를 상속합니다.

StreamRecoder 객체

StreamRecoder는 한 인코딩에서 다른 인코딩으로 데이터를 변환하는데, 이는 때때로 다른 인코딩 환경을 다룰 때 유용합니다.

lookup() 함수가 반환한 팩토리 함수를 사용하여 인스턴스를 구성할 수 있도록 설계되었습니다.

class codecs.StreamRecoder(stream, encode, decode, Reader, Writer, errors='strict')

Creates a StreamRecoder instance which implements a two-way conversion: encode and decode work on the frontend — the data visible to code calling read() and write(), while Reader and Writer work on the backend — the data in stream.

이러한 객체를 사용하여 투명한 트랜스코딩을 수행 할 수 있습니다, 예를 들어, Latin-1 에서 UTF-8로 또는 그 반대로.

stream 인자는 파일류 객체여야 합니다.

encode와 decode 인자는 Codec 인터페이스를 준수해야 합니다. Reader와 Writer는 각각 StreamReader와 StreamWriter 인터페이스의 객체를 제공하는 팩토리 함수나 클래스여야 합니다.

에러 처리는 스트림 판독기와 기록기에 정의된 것과 같은 방식으로 수행됩니다.

StreamRecoder 인스턴스는 StreamReader와 StreamWriter 클래스가 결합한 인터페이스를 정의합니다. 하부 스트림에서 다른 모든 메서드와 어트리뷰트를 상속합니다.

인코딩과 유니코드

Strings are stored internally as sequences of code points in range U+0000–U+10FFFF. (See PEP 393 [https://peps.python.org/pep-0393/] for more details about the implementation.) Once a string object is used outside of CPU and memory, endianness and how these arrays are stored as bytes become an issue. As with other codecs, serialising a string into a sequence of bytes is known as encoding, and recreating the string from the sequence of bytes is known as decoding. There are a variety of different text serialisation codecs, which are collectivity referred to as text encodings.

가장 간단한 텍스트 인코딩('latin-1' 또는 'iso-8859-1'이라고 합니다)은 코드 포인트 0–255를 바이트 0x0–0xff로 매핑합니다. 이것은 U+00FF 위의 코드 포인트를 포함하는 문자열 객체는 이 코덱으로 인코딩할 수 없음을 뜻합니다. 그렇게 하면 다음과 유사한 UnicodeEncodeError 가 발생합니다 (에러 메시지의 세부 사항은 다를 수 있습니다): UnicodeEncodeError: 'latin-1' codec can't encode character '\u1234' in position 3: ordinal not in range(256).

모든 유니코드 코드 포인트의 다른 부분 집합과 이러한 코드 포인트가 바이트 0x0–0xff에 매핑되는 방식을 선택하는 또 다른 인코딩 그룹(소위 charmap 인코딩)이 있습니다. 이 작업을 수행하는 방법을 보려면 간단히 예를 들어 encodings/cp1252.py(윈도우에서 주로 사용되는 인코딩)를 열어보십시오. 어떤 문자가 어떤 바이트 값에 매핑되는지를 나타내는 256개의 문자로 구성된 문자열 상수가 있습니다.

All of these encodings can only encode 256 of the 1114112 code points defined in Unicode. A simple and straightforward way that can store each Unicode code point, is to store each code point as four consecutive bytes. There are two possibilities: store the bytes in big endian or in little endian order. These two encodings are called UTF-32-BE and UTF-32-LE respectively. Their disadvantage is that if e.g. you use UTF-32-BE on a little endian machine you will always have to swap bytes on encoding and decoding. UTF-32 avoids this problem: bytes will always be in natural endianness. When these bytes are read by a CPU with a different endianness, then bytes have to be swapped though. To be able to detect the endianness of a UTF-16 or UTF-32 byte sequence, there’s the so called BOM (“Byte Order Mark”). This is the Unicode character U+FEFF. This character can be prepended to every UTF-16 or UTF-32 byte sequence. The byte swapped version of this character (0xFFFE) is an illegal character that may not appear in a Unicode text. So when the first character in a UTF-16 or UTF-32 byte sequence appears to be a U+FFFE the bytes have to be swapped on decoding. Unfortunately the character U+FEFF had a second purpose as a ZERO WIDTH NO-BREAK SPACE: a character that has no width and doesn’t allow a word to be split. It can e.g. be used to give hints to a ligature algorithm. With Unicode 4.0 using U+FEFF as a ZERO WIDTH NO-BREAK SPACE has been deprecated (with U+2060 (WORD JOINER) assuming this role). Nevertheless Unicode software still must be able to handle U+FEFF in both roles: as a BOM it’s a device to determine the storage layout of the encoded bytes, and vanishes once the byte sequence has been decoded into a string; as a ZERO WIDTH NO-BREAK SPACE it’s a normal character that will be decoded like any other.

There’s another encoding that is able to encode the full range of Unicode characters: UTF-8. UTF-8 is an 8-bit encoding, which means there are no issues with byte order in UTF-8. Each byte in a UTF-8 byte sequence consists of two parts: marker bits (the most significant bits) and payload bits. The marker bits are a sequence of zero to four 1 bits followed by a 0 bit. Unicode characters are encoded like this (with x being payload bits, which when concatenated give the Unicode character):

범위

인코딩

U-00000000 … U-0000007F

0xxxxxxx

U-00000080 … U-000007FF

110xxxxx 10xxxxxx

U-00000800 … U-0000FFFF

1110xxxx 10xxxxxx 10xxxxxx

U-00010000 … U-0010FFFF

11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

유니코드 문자의 최하위 비트는 가장 오른쪽에 있는 x 비트입니다.

UTF-8은 8비트 인코딩이라서 BOM이 필요하지 않으며 디코딩된 문자열의 모든 U+FEFF 문자(첫 번째 문자라 할지라도)는 ZERO WIDTH NO-BREAK SPACE로 처리됩니다.

Without external information it’s impossible to reliably determine which encoding was used for encoding a string. Each charmap encoding can decode any random byte sequence. However that’s not possible with UTF-8, as UTF-8 byte sequences have a structure that doesn’t allow arbitrary byte sequences. To increase the reliability with which a UTF-8 encoding can be detected, Microsoft invented a variant of UTF-8 (that Python calls "utf-8-sig") for its Notepad program: Before any of the Unicode characters is written to the file, a UTF-8 encoded BOM (which looks like this as a byte sequence: 0xef, 0xbb, 0xbf) is written. As it’s rather improbable that any charmap encoded file starts with these byte values (which would e.g. map to

LATIN SMALL LETTER I WITH DIAERESIS

RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK

INVERTED QUESTION MARK

), 바이트 시퀀스에서 utf-8-sig 인코딩을 정확하게 추측할 수 있는 가능성을 높입니다. 따라서 여기서 BOM은 바이트 시퀀스를 생성하는 데 사용되는 바이트 순서를 결정할 수 있도록 하는데 사용되지는 않지만, 인코딩을 추측하는 데 도움이 되는 서명으로 사용됩니다. 인코딩할 때 utf-8-sig 코덱은 0xef, 0xbb, 0xbf를 파일의 처음 3바이트로 기록합니다. 디코딩할 때 utf-8-sig는 파일에서 처음 3바이트에 등장하면 이 3바이트를 건너뜁니다. UTF-8에서는, BOM 사용을 권장하지 않으며 일반적으로 피해야 합니다.

표준 인코딩

파이썬에는 C 함수로 구현되거나 딕셔너리를 매핑 테이블로 사용하는 많은 코덱이 내장되어 있습니다. 다음 표는 몇 가지 공통 별칭과 인코딩이 사용되는 언어와 함께 이름별로 코덱을 나열합니다. 별칭 목록이나 언어 목록이 모두 철저하지는 않습니다. 대소 문자만 다르거나 밑줄 대신 하이픈을 사용하는 철자 대안도 유효한 별칭임에 유의하십시오; 따라서, 예를 들어 'utf-8'은 'utf_8' 코덱의 유효한 별칭입니다.

On Windows, cpXXX codecs are available for all code pages. But only codecs listed in the following table are guarantead to exist on other platforms.

CPython 구현 상세: 일부 공통 인코딩은 코덱 조회 메커니즘을 우회하여 성능을 향상할 수 있습니다. 이러한 최적화 기회는 CPython에서만 제한된 (대소 문자를 구분하는) 별칭 집합에 대해서 인식됩니다: utf-8, utf8, latin-1, latin1, iso-8859-1, iso8859-1, mbcs (윈도우 전용), ascii, us-ascii, utf-16, utf16, utf-32, utf32 및 대시 대신 밑줄을 사용한 것들. 이러한 인코딩에 대체 대안 별칭을 사용하면 실행 속도가 느려질 수 있습니다.

버전 3.6에서 변경: us-ascii에서 최적화 기회가 인식됩니다.

많은 문자 집합이 같은 언어를 지원합니다. 개별 문자(예를 들어 EURO SIGN 지원 여부)와 코드 위치에 문자를 대입하는 것에서 다릅니다. 특히 유럽 언어의 경우, 일반적으로 다음과 같은 변형이 있습니다:

ISO 8859 코드 집합

Microsoft 윈도우 코드 페이지, 일반적으로 8859 코드 집합에서 파생되지만, 제어 문자를 추가 그래픽 문자로 대체합니다

IBM EBCDIC 코드 페이지

IBM PC 코드 페이지, ASCII와 호환됩니다

코덱

별칭

언어

ascii

646, us-ascii

영어

big5

big5-tw, csbig5

중국어 번체

big5hkscs

big5-hkscs, hkscs

중국어 번체

cp037

IBM037, IBM039

영어

cp273

273, IBM273, csIBM273

독일어

Added in version 3.4.

cp424

EBCDIC-CP-HE, IBM424

히브리어

cp437

437, IBM437

영어

cp500

EBCDIC-CP-BE, EBCDIC-CP-CH, IBM500

서유럽어

cp720

아랍어

cp737

그리스어

cp775

IBM775

발트어

cp850

850, IBM850

서유럽어

cp852

852, IBM852

중부와 동유럽어

cp855

855, IBM855

불가리아어, 벨로루시야어, 마케도니아어, 러시아어, 세르비아어

cp856

히브리어

cp857

857, IBM857

터키어

cp858

858, IBM858

서유럽어

cp860

860, IBM860

포르투갈어

cp861

861, CP-IS, IBM861

아이슬란드어

cp862

862, IBM862

히브리어

cp863

863, IBM863

캐나다어

cp864

IBM864

아랍어

cp865

865, IBM865

덴마크어, 노르웨이어

cp866

866, IBM866

러시아어

cp869

869, CP-GR, IBM869

그리스어

cp874

태국어

cp875

그리스어

cp932

932, ms932, mskanji, ms-kanji, windows-31j

일본어

cp949

949, ms949, uhc

한국어

cp950

950, ms950

중국어 번체

cp1006

우르두어

cp1026

ibm1026

터키어

cp1125

1125, ibm1125, cp866u, ruscii

우크라이나어

Added in version 3.4.

cp1140

ibm1140

서유럽어

cp1250

windows-1250

중부와 동유럽어

cp1251

windows-1251

불가리아어, 벨로루시야어, 마케도니아어, 러시아어, 세르비아어

cp1252

windows-1252

서유럽어

cp1253

windows-1253

그리스어

cp1254

windows-1254

터키어

cp1255

windows-1255

히브리어

cp1256

windows-1256

아랍어

cp1257

windows-1257

발트어

cp1258

windows-1258

베트남어

euc_jp

eucjp, ujis, u-jis

일본어

euc_jis_2004

jisx0213, eucjis2004

일본어

euc_jisx0213

eucjisx0213

일본어

euc_kr

euckr, korean, ksc5601, ks_c-5601, ks_c-5601-1987, ksx1001, ks_x-1001

한국어

gb2312

chinese, csiso58gb231280, euc-cn, euccn, eucgb2312-cn, gb2312-1980, gb2312-80, iso-ir-58

중국어 간체

gbk

936, cp936, ms936

통합 중국어

gb18030

gb18030-2000

통합 중국어

hz

hzgb, hz-gb, hz-gb-2312

중국어 간체

iso2022_jp

csiso2022jp, iso2022jp, iso-2022-jp

일본어

iso2022_jp_1

iso2022jp-1, iso-2022-jp-1

일본어

iso2022_jp_2

iso2022jp-2, iso-2022-jp-2

일본어, 한국어, 중국어 간체, 서유럽어, 그리스어

iso2022_jp_2004

iso2022jp-2004, iso-2022-jp-2004

일본어

iso2022_jp_3

iso2022jp-3, iso-2022-jp-3

일본어

iso2022_jp_ext

iso2022jp-ext, iso-2022-jp-ext

일본어

iso2022_kr

csiso2022kr, iso2022kr, iso-2022-kr

한국어

latin_1

iso-8859-1, iso8859-1, 8859, cp819, latin, latin1, L1

서유럽어

iso8859_2

iso-8859-2, latin2, L2

중부와 동유럽어

iso8859_3

iso-8859-3, latin3, L3

에스페란토어, 몰타어

iso8859_4

iso-8859-4, latin4, L4

발트어

iso8859_5

iso-8859-5, cyrillic

불가리아어, 벨로루시야어, 마케도니아어, 러시아어, 세르비아어

iso8859_6

iso-8859-6, arabic

아랍어

iso8859_7

iso-8859-7, greek, greek8

그리스어

iso8859_8

iso-8859-8, hebrew

히브리어

iso8859_9

iso-8859-9, latin5, L5

터키어

iso8859_10

iso-8859-10, latin6, L6

북유럽어

iso8859_11

iso-8859-11, thai

태국어

iso8859_13

iso-8859-13, latin7, L7

발트어

iso8859_14

iso-8859-14, latin8, L8

켈틱어

iso8859_15

iso-8859-15, latin9, L9

서유럽어

iso8859_16

iso-8859-16, latin10, L10

남유럽어

johab

cp1361, ms1361

한국어

koi8_r

러시아어

koi8_t

타지크어

Added in version 3.5.

koi8_u

우크라이나어

kz1048

kz_1048, strk1048_2002, rk1048

카자흐어

Added in version 3.5.

mac_cyrillic

maccyrillic

불가리아어, 벨로루시야어, 마케도니아어, 러시아어, 세르비아어

mac_greek

macgreek

그리스어

mac_iceland

maciceland

아이슬란드어

mac_latin2

maclatin2, maccentraleurope, mac_centeuro

중부와 동유럽어

mac_roman

macroman, macintosh

서유럽어

mac_turkish

macturkish

터키어

ptcp154

csptcp154, pt154, cp154, cyrillic-asian

카자흐어

shift_jis

csshiftjis, shiftjis, sjis, s_jis

일본어

shift_jis_2004

shiftjis2004, sjis_2004, sjis2004

일본어

shift_jisx0213

shiftjisx0213, sjisx0213, s_jisx0213

일본어

utf_32

U32, utf32

모든 언어

utf_32_be

UTF-32BE

모든 언어

utf_32_le

UTF-32LE

모든 언어

utf_16

U16, utf16

모든 언어

utf_16_be

UTF-16BE

모든 언어

utf_16_le

UTF-16LE

모든 언어

utf_7

U7, unicode-1-1-utf-7

모든 언어

utf_8

U8, UTF, utf8, cp65001

모든 언어

utf_8_sig

모든 언어

버전 3.4에서 변경: utf-16* 과 utf-32* 인코더는 더는 서로게이트 코드 포인트(U+D800–U+DFFF)를 인코딩할 수 없습니다. utf-32* 디코더는 더는 서로게이트 코드 포인트에 해당하는 바이트 시퀀스를 디코딩하지 않습니다.

버전 3.8에서 변경: cp65001은 이제 utf_8의 별칭입니다.

버전 3.14에서 변경: On Windows, cpXXX codecs are now available for all code pages.

파이썬 특정 인코딩

사전 정의된 많은 코덱이 파이썬에만 해당하여, 코덱 이름은 파이썬 외부에서 의미가 없습니다. 예상되는 입력과 출력형에 따라 아래 표에 나열되어 있습니다 (텍스트 인코딩은 코덱의 가장 일반적인 사용 사례이지만, 하부 코덱 인프라는 단지 텍스트 인코딩이 아닌 임의의 데이터 변환을 지원합니다). 비대칭 코덱의 경우, 언급된 의미는 인코딩 방향을 설명합니다.

텍스트 인코딩

다음 코덱은 유니코드 텍스트 인코딩과 유사하게, str에서 bytes로의 인코딩과 바이트열류 객체에서 str로의 디코딩을 제공합니다.

코덱

별칭

의미

idna

RFC 3490 [https://datatracker.ietf.org/doc/html/rfc3490.html]을 구현합니다. encodings.idna도 참조하십시오. errors='strict'만 지원됩니다.

mbcs

ansi, dbcs

윈도우 전용: ANSI 코드 페이지(CP_ACP)에 따라 피연산자를 인코딩합니다.

oem

윈도우 전용: OEM 코드 페이지(CP_OEMCP)에 따라 피연산자를 인코딩합니다.

Added in version 3.6.

palmos

PalmOS 3.5의 인코딩.

punycode

RFC 3492 [https://datatracker.ietf.org/doc/html/rfc3492.html]를 구현합니다. 상태 있는 코덱은 지원되지 않습니다.

raw_unicode_escape

Latin-1 encoding with \uXXXX and \UXXXXXXXX for other code points. Existing backslashes are not escaped in any way. It is used in the Python pickle protocol.

undefined

모든 변환에 대해 예외를 발생시킵니다, 빈 문자열조차. 에러 처리기는 무시됩니다.

unicode_escape

따옴표가 이스케이프 되지 않는 것을 제외하고, ASCII로 인코딩된 파이썬 소스 코드에서 유니코드 리터럴 내용으로 적합한 인코딩. Latin-1 소스 코드에서 디코딩합니다. 파이썬 소스 코드는 실제로는 기본적으로 UTF-8을 사용합니다.

버전 3.8에서 변경: “unicode_internal” 코덱이 제거되었습니다.

바이너리 변환

다음 코덱은 바이너리 변환을 제공합니다: 바이트열류 객체에서 bytes로의 매핑. (str 출력만 생성하는) bytes.decode()에서는 지원되지 않습니다.

코덱

별칭

의미

인코더 / 디코더

base64_codec [1]

base64, base_64

피연산자를 여러 줄 MIME base64로 변환합니다 (결과에는 항상 후행 '\n'이 포함됩니다).

버전 3.4에서 변경: 인코딩과 디코딩을 위해 모든 바이트열류 객체를 입력으로 받아들입니다.

base64.encodebytes() / base64.decodebytes()

bz2_codec

bz2

bz2를 사용하여 피연산자를 압축합니다.

bz2.compress() / bz2.decompress()

hex_codec

hex

바이트 당 두 자리 숫자를 사용하여, 피연산자를 16진 표현으로 변환합니다.

binascii.b2a_hex() / binascii.a2b_hex()

quopri_codec

quopri, quotedprintable, quoted_printable

피연산자를 MIME quoted printable로 변환합니다.

quotetabs=True를 사용한 quopri.encode() / quopri.decode()

uu_codec

uu

uuencode를 사용하여 피연산자를 변환합니다.

zlib_codec

zip, zlib

gzip을 사용하여 피연산자를 압축합니다.

zlib.compress() / zlib.decompress()

[1]

'base64_codec'는 바이트열류 객체 외에도 디코딩을 위해 ASCII만 있는 str 인스턴스도 허용합니다.

Added in version 3.2: 바이너리 변환의 복원.

버전 3.4에서 변경: 바이너리 변환에 대한 별칭의 복원.

텍스트 변환

다음 코덱은 텍스트 변환을 제공합니다: str에서 str로의 매핑. (bytes 출력만 생성하는) str.encode()에서는 지원되지 않습니다.

코덱

별칭

의미

rot_13

rot13

피연산자의 시저 암호(Caesar-cypher) 암호화를 반환합니다.

Added in version 3.2: rot_13 텍스트 변환 복원.

버전 3.4에서 변경: rot13 별칭 복원.

encodings.idna — 응용 프로그램에서의 국제화된 도메인 이름

이 모듈은 RFC 3490 [https://datatracker.ietf.org/doc/html/rfc3490.html](Internationalized Domain Names in Applications)과 RFC 3492 [https://datatracker.ietf.org/doc/html/rfc3492.html](Nameprep: A Stringprep Profile for Internationalized Domain Names (IDN))를 구현합니다. punycode 인코딩과 stringprep을 기반으로 합니다.

If you need the IDNA 2008 standard from RFC 5891 [https://datatracker.ietf.org/doc/html/rfc5891.html] and RFC 5895 [https://datatracker.ietf.org/doc/html/rfc5895.html], use the third-party idna [https://pypi.org/project/idna/] module.

이 RFC는 함께 도메인 이름에서 비 ASCII 문자를 지원하는 프로토콜을 정의합니다. 비 ASCII 문자(가령 www.Alliancefrançaise.nu)를 포함하는 도메인 이름은 ASCII 호환 인코딩(ACE, 가령 www.xn--alliancefranaise-npb.nu)으로 변환됩니다. 그런 다음 도메인 이름의 ACE 형식은 DNS 조회, HTTP Host 필드 등과 같이 프로토콜에 의해 임의의 문자가 허용되지 않는 모든 위치에서 사용됩니다. 이 변환은 응용 프로그램에서 수행됩니다; 가능하다면 사용자에게 보이지 않습니다: 응용 프로그램은 전송 시에 유니코드 도메인 레이블을 투명하게 IDNA로 변환하고, 사용자에게 표시하기 전에 ACE 레이블을 다시 유니코드로 변환해야 합니다.

파이썬은 여러 가지 방식으로 이 변환을 지원합니다: idna 코덱은 유니코드와 ACE 간의 변환을 수행하여, RFC 3490의 섹션 3.1 [https://datatracker.ietf.org/doc/html/rfc3490.html#section-3.1]에 정의된 구분 문자를 기반으로 입력 문자열을 레이블로 분리하고 필요에 따라 각 레이블을 ACE로 변환하고, 반대로 입력 바이트 문자열을 . 구분 기호를 기반으로 레이블로 분리하고 모든 ACE 레이블을 유니코드로 변환합니다. 또한, socket 모듈은 유니코드 호스트 이름을 투명하게 ACE로 변환하므로, 응용 프로그램이 호스트 이름을 소켓 모듈로 전달할 때 호스트 이름 자체를 변환할 필요가 없습니다. 이에 더해, http.client와 ftplib와 같은, 함수 매개 변수로 호스트 이름이 있는 모듈은 유니코드 호스트 이름을 받아들입니다 (http.client는 해당 필드를 전송한다면 Host 필드에 IDNA 호스트 이름을 투명하게 전송합니다).

회선에서 호스트 이름을 수신할 때 (가령 역 이름 조회(reverse name lookup)에서), 유니코드로 자동 변환되지 않습니다: 이러한 호스트 이름을 사용자에게 제시하려는 응용 프로그램은 유니코드로 디코딩해야 합니다.

또한 모듈 encodings.idna는 nameprep 절차를 구현합니다. 이는 국제 도메인 이름의 대소 문자를 구분하지 않고 유사한 문자를 통합하기 위해 호스트 이름에 대해 특정 정규화를 수행합니다. 원한다면 nameprep 함수를 직접 사용할 수 있습니다.

encodings.idna.nameprep(label)

label의 nameprep 된 버전을 반환합니다. 구현은 현재 쿼리 문자열을 가정하므로, AllowUnassigned는 참입니다.

encodings.idna.ToASCII(label)

RFC 3490 [https://datatracker.ietf.org/doc/html/rfc3490.html]에 지정된 대로 레이블을 ASCII로 변환합니다. UseSTD3ASCIIRules는 거짓으로 가정합니다.

encodings.idna.ToUnicode(label)

RFC 3490 [https://datatracker.ietf.org/doc/html/rfc3490.html]에 지정된 대로 레이블을 유니코드로 변환합니다.

encodings.mbcs — 윈도우 ANSI 코드 페이지

이 모듈은 ANSI 코드 페이지(CP_ACP)를 구현합니다.

Availability: Windows.

버전 3.2에서 변경: 3.2 이전에는, errors 인자가 무시되었습니다; 인코딩에는 항상 'replace'가 사용되고, 디코딩에는 항상 'ignore'가 사용되었습니다.

버전 3.3에서 변경: 모든 에러 처리기를 지원합니다.

encodings.utf_8_sig — BOM 서명이 있는 UTF-8 코덱

이 모듈은 UTF-8 코덱의 변형을 구현합니다. 인코딩 시, UTF-8로 인코딩된 BOM을 UTF-8로 인코딩된 바이트열 앞에 붙입니다. 상태 있는 인코더의 경우 이 작업은 한 번만 수행됩니다 (바이트 스트림에 대한 첫 번째 쓰기 시). 디코딩 시, 데이터 시작에 있는 선택적 UTF-8 인코딩된 BOM을 건너뜁니다.

데이터형

이 장에서 설명하는 모듈은 날짜와 시간, 고정형 배열, 힙 큐, 데크, 열거형과 같은 다양한 특수 데이터형을 제공합니다.

파이썬은 또한 일부 내장 데이터형, 특히 dict, list, set과 frozenset, tuple을 제공합니다. str 클래스는 유니코드 문자열을 저장하는 데 사용되고, bytes와 bytearray 클래스는 바이너리 데이터를 저장하는 데 사용됩니다.

이 장에서는 다음 모듈에 관해 설명합니다:

datetime — Basic date and time types

어웨어와 나이브 객체

상수

MINYEAR

MAXYEAR

UTC

사용 가능한 형

공통 속성

객체가 어웨어한지 나이브한지 판단하기

timedelta 객체

timedelta

min

max

resolution

days

seconds

microseconds

total_seconds()

사용 예: timedelta

date 객체

date

today()

fromtimestamp()

fromordinal()

fromisoformat()

fromisocalendar()

strptime()

min

max

resolution

year

month

day

replace()

timetuple()

toordinal()

weekday()

isoweekday()

isocalendar()

isoformat()

__str__()

ctime()

strftime()

__format__()

사용 예: date

datetime 객체

datetime

today()

now()

utcnow()

fromtimestamp()

utcfromtimestamp()

fromordinal()

combine()

fromisoformat()

fromisocalendar()

strptime()

min

max

resolution

year

month

day

hour

minute

second

microsecond

tzinfo

fold

date()

time()

timetz()

replace()

astimezone()

utcoffset()

dst()

tzname()

timetuple()

utctimetuple()

toordinal()

timestamp()

weekday()

isoweekday()

isocalendar()

isoformat()

__str__()

ctime()

strftime()

__format__()

사용 예: datetime

time 객체

time

min

max

resolution

hour

minute

second

microsecond

tzinfo

fold

fromisoformat()

strptime()

replace()

isoformat()

__str__()

strftime()

__format__()

utcoffset()

dst()

tzname()

사용 예: time

tzinfo 객체

tzinfo

utcoffset()

dst()

tzname()

fromutc()

timezone 객체

timezone

utcoffset()

tzname()

dst()

fromutc()

utc

strftime() and strptime() Behavior

strftime() and strptime() Format Codes

기술적 세부 사항

zoneinfo — IANA time zone support

ZoneInfo 사용하기

데이터 소스

데이터 소스 구성

컴파일 시간 구성

환경 구성

실행 시간 구성

ZoneInfo 클래스

ZoneInfo

from_file()

no_cache()

clear_cache()

key

문자열 표현

피클 직렬화

함수

available_timezones()

reset_tzpath()

전역

TZPATH

예외와 경고

ZoneInfoNotFoundError

InvalidTZPathWarning

calendar — General calendar-related functions

Calendar

iterweekdays()

itermonthdates()

itermonthdays()

itermonthdays2()

itermonthdays3()

itermonthdays4()

monthdatescalendar()

monthdays2calendar()

monthdayscalendar()

yeardatescalendar()

yeardays2calendar()

yeardayscalendar()

TextCalendar

formatmonth()

prmonth()

formatyear()

pryear()

HTMLCalendar

formatmonth()

formatyear()

formatyearpage()

formatmonthname()

cssclasses

cssclass_noday

cssclasses_weekday_head

cssclass_month_head

cssclass_month

cssclass_year

cssclass_year_head

LocaleTextCalendar

LocaleHTMLCalendar

setfirstweekday()

firstweekday()

isleap()

leapdays()

weekday()

weekheader()

monthrange()

monthcalendar()

prmonth()

month()

prcal()

calendar()

timegm()

day_name

day_abbr

MONDAY

TUESDAY

WEDNESDAY

THURSDAY

FRIDAY

SATURDAY

SUNDAY

Day

month_name

month_abbr

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

JULY

AUGUST

SEPTEMBER

OCTOBER

NOVEMBER

DECEMBER

Month

IllegalMonthError

month

IllegalWeekdayError

weekday

Command-Line Usage

collections — Container datatypes

ChainMap 객체

ChainMap

maps

new_child()

parents

ChainMap 예제와 조리법

Counter 객체

Counter

elements()

most_common()

subtract()

total()

fromkeys()

update()

deque 객체

deque

append()

appendleft()

clear()

copy()

count()

extend()

extendleft()

index()

insert()

pop()

popleft()

remove()

reverse()

rotate()

maxlen

deque 조리법

defaultdict 객체

defaultdict

__missing__()

default_factory

defaultdict 예

이름있는 필드를 가진 튜플을 위한 namedtuple() 팩토리 함수

namedtuple()

_make()

_asdict()

_replace()

_fields

_field_defaults

OrderedDict 객체

OrderedDict

popitem()

move_to_end()

OrderedDict 예제와 조리법

UserDict 객체

UserDict

data

UserList 객체

UserList

data

UserString 객체

UserString

data

collections.abc — Abstract Base Classes for Containers

Collections 추상 베이스 클래스

Collections Abstract Base Classes – Detailed Descriptions

Container

Hashable

Sized

Callable

Iterable

Collection

Iterator

Reversible

Generator

Sequence

MutableSequence

Set

MutableSet

Mapping

MutableMapping

MappingView

ItemsView

KeysView

ValuesView

Awaitable

Coroutine

AsyncIterable

AsyncIterator

AsyncGenerator

Buffer

Examples and Recipes

heapq — Heap queue algorithm

heappush()

heappop()

heappushpop()

heapify()

heapreplace()

merge()

nlargest()

nsmallest()

기본 예

우선순위 큐 구현 참고 사항

이론

bisect — Array bisection algorithm

bisect_left()

bisect_right()

bisect()

insort_left()

insort_right()

insort()

Performance Notes

정렬된 리스트 검색하기

Examples

array — Efficient arrays of numeric values

typecodes

array

typecode

itemsize

append()

buffer_info()

byteswap()

count()

extend()

frombytes()

fromfile()

fromlist()

fromunicode()

index()

insert()

pop()

remove()

clear()

reverse()

tobytes()

tofile()

tolist()

tounicode()

weakref — 약한 참조

ref

__callback__

proxy()

getweakrefcount()

getweakrefs()

WeakKeyDictionary

keyrefs()

WeakValueDictionary

valuerefs()

WeakSet

WeakMethod

finalize

__call__()

detach()

peek()

alive

atexit

ReferenceType

ProxyType

CallableProxyType

ProxyTypes

약한 참조 객체

예

파이널라이저 객체

Comparing finalizers with __del__() methods

types — Dynamic type creation and names for built-in types

동적 형 생성

new_class()

prepare_class()

resolve_bases()

get_original_bases()

표준 인터프리터 형

NoneType

FunctionType

LambdaType

GeneratorType

CoroutineType

AsyncGeneratorType

CodeType

CellType

MethodType

BuiltinFunctionType

BuiltinMethodType

WrapperDescriptorType

MethodWrapperType

NotImplementedType

MethodDescriptorType

ClassMethodDescriptorType

ModuleType

EllipsisType

GenericAlias

UnionType

TracebackType

FrameType

GetSetDescriptorType

MemberDescriptorType

MappingProxyType

copy()

get()

items()

keys()

values()

CapsuleType

추가 유틸리티 클래스와 함수

SimpleNamespace

DynamicClassAttribute()

코루틴 유틸리티 함수

coroutine()

copy — Shallow and deep copy operations

copy()

deepcopy()

replace()

Error

__copy__()

__deepcopy__()

__replace__()

pprint — Data pretty printer

Functions

pp()

pprint()

pformat()

isreadable()

isrecursive()

saferepr()

PrettyPrinter 객체

PrettyPrinter

pformat()

pprint()

isreadable()

isrecursive()

format()

예제

reprlib — Alternate repr() implementation

Repr

aRepr

repr()

recursive_repr()

Repr 객체

fillvalue

maxlevel

maxdict

maxlist

maxtuple

maxset

maxfrozenset

maxdeque

maxarray

maxlong

maxstring

maxother

indent

repr()

repr1()

Repr 객체 서브 클래싱

enum — Support for enumerations

모듈 내용

Data Types

EnumType

__call__()

__contains__()

__dir__()

__getitem__()

__iter__()

__len__()

__members__

__reversed__()

_add_alias_()

_add_value_alias_()

Enum

name

value

_name_

_value_

_order_

_ignore_

__dir__()

_generate_next_value_()

__init__()

__init_subclass__()

_missing_()

__new__()

__repr__()

__str__()

__format__()

IntEnum

StrEnum

Flag

__contains__()

__or__()

__and__()

__xor__()

_numeric_repr_()

IntFlag

ReprEnum

EnumCheck

UNIQUE

CONTINUOUS

NAMED_FLAGS

FlagBoundary

STRICT

CONFORM

EJECT

KEEP

지원되는 __dunder__ 이름

지원되는 _sunder_ 이름

Utilities and Decorators

auto

property()

unique()

verify()

member()

nonmember()

global_enum()

show_flag_values()

Notes

graphlib — Functionality to operate with graph-like structures

TopologicalSorter

add()

prepare()

is_active()

done()

get_ready()

static_order()

예외

CycleError

datetime — Basic date and time types

소스 코드: Lib/datetime.py [https://github.com/python/cpython/tree/main/Lib/datetime.py]

The datetime module supplies classes for manipulating dates and times.

날짜와 시간 산술이 지원되지만, 구현의 초점은 출력 포매팅과 조작을 위한 효율적인 어트리뷰트 추출입니다.

팁

Skip to the format codes.

더 보기

모듈 calendar

일반 달력 관련 함수들.

모듈 time

시간 액세스와 변환.

Module zoneinfo

Concrete time zones representing the IANA time zone database.

패키지 dateutil [https://dateutil.readthedocs.io/en/stable/]

시간대와 구문 분석 지원이 확장된 제삼자 라이브러리.

Package DateType [https://pypi.org/project/DateType/]

Third-party library that introduces distinct static types to e.g. allow static type checkers to differentiate between naive and aware datetimes.

어웨어와 나이브 객체

Date and time objects may be categorized as “aware” or “naive” depending on whether or not they include time zone information.

시간대와 일광 절약 시간 정보와 같은 적용 가능한 알고리즘과 정치적 시간 조정에 대한 충분한 지식을 통해, 어웨어 객체는 다른 어웨어 객체와의 상대적인 위치를 파악할 수 있습니다. 어웨어 객체는 자의적으로 해석할 여지 없는 특정 시간을 나타냅니다. [1]

A naive object does not contain enough information to unambiguously locate itself relative to other date/time objects. Whether a naive object represents Coordinated Universal Time (UTC), local time, or time in some other time zone is purely up to the program, just like it is up to the program whether a particular number represents metres, miles, or mass. Naive objects are easy to understand and to work with, at the cost of ignoring some aspects of reality.

어웨어 객체가 필요한 응용 프로그램을 위해, datetime 과 time 객체에는 추상 tzinfo 클래스의 서브 클래스 인스턴스로 설정할 수 있는 선택적 시간대 정보 어트리뷰트인 tzinfo가 있습니다. 이러한 tzinfo 객체는 UTC 시간으로부터의 오프셋, 시간대 이름 및 일광 절약 시간이 적용되는지에 대한 정보를 보관합니다.

Only one concrete tzinfo class, the timezone class, is supplied by the datetime module. The timezone class can represent simple time zones with fixed offsets from UTC, such as UTC itself or North American EST and EDT time zones. Supporting time zones at deeper levels of detail is up to the application. The rules for time adjustment across the world are more political than rational, change frequently, and there is no standard suitable for every application aside from UTC.

상수

The datetime module exports the following constants:

datetime.MINYEAR

The smallest year number allowed in a date or datetime object. MINYEAR is 1.

datetime.MAXYEAR

The largest year number allowed in a date or datetime object. MAXYEAR is 9999.

datetime.UTC

Alias for the UTC time zone singleton datetime.timezone.utc.

Added in version 3.11.

사용 가능한 형

class datetime.date

현재의 그레고리력이 언제나 적용되어왔고, 앞으로도 그럴 것이라는 가정하에 이상적인 나이브 날짜. 어트리뷰트: year, month 및 day.

class datetime.time

특정 날짜와 관계없이, 하루가 정확히 24*60*60초를 갖는다는 가정하에 이상적인 시간. (여기에는 “윤초”라는 개념이 없습니다.) 어트리뷰트: hour, minute, second, microsecond 및 tzinfo.

class datetime.datetime

날짜와 시간의 조합. 어트리뷰트: year, month, day, hour, minute, second, microsecond 및 tzinfo.

class datetime.timedelta

A duration expressing the difference between two datetime or date instances to microsecond resolution.

class datetime.tzinfo

시간대 정보 객체의 추상 베이스 클래스. 이것들은 datetime과 time 클래스에서 사용자 정의할 수 있는 시간 조정 개념(예를 들어, 시간대와/나 일광 절약 시간을 다루는 것)을 제공하기 위해 사용됩니다.

class datetime.timezone

tzinfo 추상 베이스 클래스를 구현하는 클래스로, UTC로부터의 고정 오프셋을 나타냅니다.

Added in version 3.2.

이러한 형의 객체는 불변입니다.

서브 클래스 관계:

object
    timedelta
    tzinfo
        timezone
    time
    date
        datetime

공통 속성

date, datetime, time 및 timezone 형은 다음과 같은 공통 기능을 공유합니다:

이러한 형의 객체는 불변입니다.

Objects of these types are hashable, meaning that they can be used as dictionary keys.

이러한 형의 객체는 pickle 모듈을 통한 효율적인 피클링을 지원합니다.

객체가 어웨어한지 나이브한지 판단하기

date 형의 객체는 항상 나이브합니다.

time이나 datetime 형의 객체는 어웨어할 수도 나이브할 수도 있습니다.

A datetime object d is aware if both of the following hold:

d.tzinfo가 None이 아닙니다

d.tzinfo.utcoffset(d)가 None을 반환하지 않습니다

Otherwise, d is naive.

A time object t is aware if both of the following hold:

t.tzinfo가 None이 아닙니다

t.tzinfo.utcoffset(None)이 None을 반환하지 않습니다

Otherwise, t is naive.

어웨어와 나이브 간의 차이점은 timedelta 객체에는 적용되지 않습니다.

timedelta 객체

A timedelta object represents a duration, the difference between two datetime or date instances.

class datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0)

All arguments are optional and default to 0. Arguments may be integers or floats, and may be positive or negative.

days, seconds 및 microseconds만 내부적으로 저장됩니다. 인자는 이 단위로 변환됩니다:

밀리 초는 1000마이크로초로 변환됩니다.

분은 60초로 변환됩니다.

시간은 3600초로 변환됩니다.

주는 7일로 변환됩니다.

그런 다음 days, seconds 및 microseconds를 다음처럼 정규화하여 표현이 고유하도록 만듭니다

0 <= microseconds < 1000000

0 <= seconds < 3600*24 (하루 내의 초 수)

-999999999 <= days <= 999999999

다음 예는 days, seconds 및 microseconds 이외의 인자가 어떻게 “병합” 되어 세 개의 결과 어트리뷰트로 정규화되는지를 보여줍니다:

>>> from datetime import timedelta
>>> delta = timedelta(
...     days=50,
...     seconds=27,
...     microseconds=10,
...     milliseconds=29000,
...     minutes=5,
...     hours=8,
...     weeks=2
... )
>>> # Only days, seconds, and microseconds remain
>>> delta
datetime.timedelta(days=64, seconds=29156, microseconds=10)

인자가 float이고 부분 마이크로초가 있으면, 모든 인자의 남은 부분 마이크로초가 합쳐지고, 그 합은 동률일 때 짝수로 반올림하는 방식으로 가장 가까운 마이크로초로 반올림됩니다. float 인자가 없으면, 변환과 정규화 프로세스는 정확합니다 (정보가 손실되지 않습니다).

정규화된 days 값이 표시된 범위를 벗어나면, OverflowError가 발생합니다.

음수 값의 정규화는 처음 보면 놀라울 수 있습니다. 예를 들어:

>>> from datetime import timedelta
>>> d = timedelta(microseconds=-1)
>>> (d.days, d.seconds, d.microseconds)
(-1, 86399, 999999)

클래스 어트리뷰트:

timedelta.min

가장 음수인 timedelta 객체, timedelta(-999999999).

timedelta.max

가장 양수인 timedelta 객체, timedelta(days=999999999, hours=23, minutes=59, seconds=59, microseconds=999999).

timedelta.resolution

같지 않은 timedelta 객체 간의 가능한 가장 작은 차이, timedelta(microseconds=1).

Note that, because of normalization, timedelta.max is greater than -timedelta.min. -timedelta.max is not representable as a timedelta object.

인스턴스 어트리뷰트 (읽기 전용):

timedelta.days

Between -999,999,999 and 999,999,999 inclusive.

timedelta.seconds

Between 0 and 86,399 inclusive.

조심

It is a somewhat common bug for code to unintentionally use this attribute when it is actually intended to get a total_seconds() value instead:

>>> from datetime import timedelta
>>> duration = timedelta(seconds=11235813)
>>> duration.days, duration.seconds
(130, 3813)
>>> duration.total_seconds()
11235813.0

timedelta.microseconds

Between 0 and 999,999 inclusive.

지원되는 연산:

연산

결과

t1 = t2 + t3

Sum of t2 and t3. Afterwards t1 - t2 == t3 and t1 - t3 == t2 are true. (1)

t1 = t2 - t3

Difference of t2 and t3. Afterwards t1 == t2 - t3 and t2 == t1 + t3 are true. (1)(6)

t1 = t2 * i 또는 t1 = i * t2

Delta multiplied by an integer. Afterwards t1 // i == t2 is true, provided i != 0.

In general, t1  * i == t1 * (i-1) + t1 is true. (1)

t1 = t2 * f 또는 t1 = f * t2

델타에 float를 곱합니다. 결과는 동률일 때 짝수로 반올림하는 방식으로 timedelta.resolution의 가장 가까운 배수로 자리 올림 됩니다.

f = t2 / t3

Division (3) of overall duration t2 by interval unit t3. Returns a float object.

t1 = t2 / f 또는 t1 = t2 / i

델타를 float나 int로 나눈 값. 결과는 동률일 때 짝수로 반올림하는 방식으로 timedelta.resolution의 가장 가까운 배수로 자리 올림 됩니다.

t1 = t2 // i 또는 t1 = t2 // t3

floor가 계산되고 나머지(있다면)를 버립니다. 두 번째 경우에는, 정수가 반환됩니다. (3)

t1 = t2 % t3

나머지가 timedelta 객체로 계산됩니다. (3)

q, r = divmod(t1, t2)

Computes the quotient and the remainder: q = t1 // t2 (3) and r = t1 % t2. q is an integer and r is a timedelta object.

+t1

같은 값을 갖는 timedelta 객체를 반환합니다. (2)

-t1

Equivalent to timedelta(-t1.days, -t1.seconds, -t1.microseconds), and to t1 * -1. (1)(4)

abs(t)

Equivalent to +t when t.days >= 0, and to -t when t.days < 0. (2)

str(t)

[D day[s], ][H]H:MM:SS[.UUUUUU] 형식의 문자열을 반환합니다. 여기서 D는 음의 t일 때 음수입니다. (5)

repr(t)

규범적 어트리뷰트 값을 가진 생성자 호출로 표현한 timedelta 객체의 문자열 표현을 반환합니다.

노트:

이것은 정확하지만, 오버플로 할 수 있습니다.

이것은 정확하고, 오버플로 할 수 없습니다.

Division by zero raises ZeroDivisionError.

-timedelta.max is not representable as a timedelta object.

timedelta 객체의 문자열 표현은 내부 표현과 유사하게 정규화됩니다. 이것은 음의 timedelta가 다소 이상하게 표현되는 결과로 이어집니다. 예를 들어:

>>> timedelta(hours=-5)
datetime.timedelta(days=-1, seconds=68400)
>>> print(_)
-1 day, 19:00:00

t2 - t3 표현식은 항상 t2 + (-t3) 표현식과 같아지는데, t3이 timedelta.max일 때만 예외입니다; 이때는 앞에 있는 것은 결과를 만들지만, 뒤에 있는 것은 오버플로를 일으킵니다.

위에 나열된 연산 외에도, timedelta 객체는 date와 datetime 객체와의 어떤 합과 차를 지원합니다 (아래를 참조하세요).

버전 3.2에서 변경: 나머지 연산과 divmod() 함수와 마찬가지로, timedelta 객체를 다른 timedelta 객체로 정수 나누기(floor division)와 실수 나누기(true division)가 이제 지원됩니다. timedelta 객체를 float 객체로 실수 나누기와 곱셈도 이제 이제 지원됩니다.

timedelta objects support equality and order comparisons.

불리언 문맥에서 timedelta 객체는 timedelta(0)와 같지 않을 때만 참으로 간주합니다.

인스턴스 메서드:

timedelta.total_seconds()

기간에 포함된 총 시간을 초(seconds)로 반환합니다. td / timedelta(seconds=1)와 동등합니다. 초 이외의 구간 단위에는, 나누기 형식을 직접 사용하십시오 (예를 들어, td / timedelta(microseconds=1)).

매우 큰 시간 구간에서는 (대부분 플랫폼에서 270년 이상), 이 메서드는 마이크로초의 정확도를 잃게 됩니다.

Added in version 3.2.

사용 예: timedelta

정규화의 추가 예:

>>> # Components of another_year add up to exactly 365 days
>>> from datetime import timedelta
>>> year = timedelta(days=365)
>>> another_year = timedelta(weeks=40, days=84, hours=23,
...                          minutes=50, seconds=600)
>>> year == another_year
True
>>> year.total_seconds()
31536000.0

timedelta 산술의 예:

>>> from datetime import timedelta
>>> year = timedelta(days=365)
>>> ten_years = 10 * year
>>> ten_years
datetime.timedelta(days=3650)
>>> ten_years.days // 365
10
>>> nine_years = ten_years - year
>>> nine_years
datetime.timedelta(days=3285)
>>> three_years = nine_years // 3
>>> three_years, three_years.days // 365
(datetime.timedelta(days=1095), 3)

date 객체

date 객체는 현재의 그레고리력을 무한히 양방향으로 확장한, 이상적인 달력에서의 날짜(년, 월, 일)를 나타냅니다.

1년 1월 1일을 날 번호 1, 1년 1월 2일을 날 번호 2라고 부르고, 이런 식으로 계속됩니다. [2]

class datetime.date(year, month, day)

모든 인자가 필수입니다. 인자는 다음 범위에 있는 정수이어야 합니다:

MINYEAR <= year <= MAXYEAR

1 <= month <= 12

1 <= day <= 주어진 month와 year에서의 날 수

이 범위를 벗어나는 인자가 주어지면, ValueError가 발생합니다.

다른 생성자, 모든 클래스 메서드:

classmethod date.today()

현재 지역 날짜를 반환합니다.

이것은 date.fromtimestamp(time.time())과 동등합니다.

classmethod date.fromtimestamp(timestamp)

time.time()에 의해 반환된 것과 같은 POSIX 타임스탬프에 해당하는 지역 날짜를 반환합니다.

타임스탬프가 플랫폼 C localtime() 함수에서 지원하는 값 범위를 벗어나면 OverflowError가 발생하고, localtime() 실패 시 OSError가 발생합니다. 이것이 1970년에서 2038년으로 제한되는 것이 일반적입니다. 타임스탬프라는 개념에 윤초를 포함하는 POSIX가 아닌 시스템에서는, 윤초가 fromtimestamp()에서 무시됨에 유의하십시오.

버전 3.3에서 변경: timestamp가 플랫폼 C localtime() 함수에서 지원하는 값 범위를 벗어나면 ValueError 대신 OverflowError를 발생시킵니다. localtime() 실패 시 ValueError 대신 OSError를 발생시킵니다.

classmethod date.fromordinal(ordinal)

역산 그레고리력 서수에 해당하는 date를 반환합니다. 1년 1월 1일이 서수 1입니다.

ValueError is raised unless 1 <= ordinal <= date.max.toordinal(). For any date d, date.fromordinal(d.toordinal()) == d.

classmethod date.fromisoformat(date_string)

Return a date corresponding to a date_string given in any valid ISO 8601 format, with the following exceptions:

Reduced precision dates are not currently supported (YYYY-MM, YYYY).

Extended date representations are not currently supported (±YYYYYY-MM-DD).

Ordinal dates are not currently supported (YYYY-OOO).

예제:

>>> from datetime import date
>>> date.fromisoformat('2019-12-04')
datetime.date(2019, 12, 4)
>>> date.fromisoformat('20191204')
datetime.date(2019, 12, 4)
>>> date.fromisoformat('2021-W01-1')
datetime.date(2021, 1, 4)

Added in version 3.7.

버전 3.11에서 변경: Previously, this method only supported the format YYYY-MM-DD.

classmethod date.fromisocalendar(year, week, day)

년, 주 및 일로 지정된 ISO 달력 날짜에 해당하는 date를 반환합니다. 이것은 함수 date.isocalendar()의 역입니다.

Added in version 3.8.

classmethod date.strptime(date_string, format)

Return a date corresponding to date_string, parsed according to format. This is equivalent to:

date(*(time.strptime(date_string, format)[0:3]))

ValueError is raised if the date_string and format can’t be parsed by time.strptime() or if it returns a value which isn’t a time tuple. See also strftime() and strptime() Behavior and date.fromisoformat().

참고

If format specifies a day of month without a year a DeprecationWarning is emitted. This is to avoid a quadrennial leap year bug in code seeking to parse only a month and day as the default year used in absence of one in the format is not a leap year. Such format values may raise an error as of Python 3.15. The workaround is to always include a year in your format. If parsing date_string values that do not have a year, explicitly add a year that is a leap year before parsing:

>>> from datetime import date
>>> date_string = "02/29"
>>> when = date.strptime(f"{date_string};1984", "%m/%d;%Y")  # Avoids leap year bug.
>>> when.strftime("%B %d")
'February 29'

Added in version 3.14.

클래스 어트리뷰트:

date.min

표현 가능한 가장 이른 date, date(MINYEAR, 1, 1).

date.max

표현 가능한 가장 늦은 date, date(MAXYEAR, 12, 31).

date.resolution

같지 않은 date 객체 간의 가능한 가장 작은 차이, timedelta(days=1).

인스턴스 어트리뷰트 (읽기 전용):

date.year

MINYEAR와 MAXYEAR 사이, 경계 포함.

date.month

1과 12 사이, 경계 포함.

date.day

1과 주어진 year의 주어진 month의 날 수 사이.

지원되는 연산:

연산

결과

date2 = date1 + timedelta

date2 will be timedelta.days days after date1. (1)

date2 = date1 - timedelta

Computes date2 such that date2 + timedelta == date1. (2)

timedelta = date1 - date2

(3)

date1 == date2

date1 != date2

Equality comparison. (4)

date1 < date2

date1 > date2

date1 <= date2

date1 >= date2

Order comparison. (5)

노트:

date2는 timedelta.days > 0이면 미래로, timedelta.days < 0이면 과거로 이동합니다. 결국 date2 - date1 == timedelta.days이 됩니다. timedelta.seconds와 timedelta.microseconds는 무시됩니다. date2.year가 MINYEAR보다 작거나 MAXYEAR보다 크게 되려고 하면 OverflowError가 발생합니다.

timedelta.seconds와 timedelta.microseconds는 무시됩니다.

This is exact, and cannot overflow. timedelta.seconds and timedelta.microseconds are 0, and date2 + timedelta == date1 after.

date objects are equal if they represent the same date.

date objects that are not also datetime instances are never equal to datetime objects, even if they represent the same date.

date1 is considered less than date2 when date1 precedes date2 in time. In other words, date1 < date2 if and only if date1.toordinal() < date2.toordinal().

Order comparison between a date object that is not also a datetime instance and a datetime object raises TypeError.

버전 3.13에서 변경: Comparison between datetime object and an instance of the date subclass that is not a datetime subclass no longer converts the latter to date, ignoring the time part and the time zone. The default behavior can be changed by overriding the special comparison methods in subclasses.

불리언 문맥에서, 모든 date 객체는 참으로 간주합니다.

인스턴스 메서드:

date.replace(year=self.year, month=self.month, day=self.day)

키워드 인자로 새로운 값이 주어진 매개 변수들을 제외하고, 같은 값을 가진 date를 반환합니다.

예제:

>>> from datetime import date
>>> d = date(2002, 12, 31)
>>> d.replace(day=26)
datetime.date(2002, 12, 26)

date objects are also supported by generic function copy.replace().

date.timetuple()

time.localtime()이 반환하는 것과 같은 time.struct_time을 반환합니다.

시, 분 및 초는 0이고, DST 플래그는 -1입니다.

d.timetuple()은 다음과 동등합니다:

time.struct_time((d.year, d.month, d.day, 0, 0, 0, d.weekday(), yday, -1))

where yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 is the day number within the current year starting with 1 for January 1st.

date.toordinal()

Return the proleptic Gregorian ordinal of the date, where January 1 of year 1 has ordinal 1. For any date object d, date.fromordinal(d.toordinal()) == d.

date.weekday()

정수로 요일을 반환합니다. 월요일은 0이고 일요일은 6입니다. 예를 들어, date(2002, 12, 4).weekday() == 2, 수요일. isoweekday()도 참조하십시오.

date.isoweekday()

정수로 요일을 반환합니다. 월요일은 1이고 일요일은 7입니다. 예를 들어, date(2002, 12, 4).isoweekday() == 3, 수요일. weekday(), isocalendar()도 참조하십시오.

date.isocalendar()

세 개의 구성 요소가 있는 네임드 튜플 객체를 반환합니다: year, week 및 weekday.

ISO 달력은 널리 사용되는 그레고리력의 변형입니다. [3]

ISO 연도는 52나 53개의 완전한 주로 구성되고, 주는 월요일에 시작하여 일요일에 끝납니다. ISO 연도의 첫 번째 주는 그 해의 (그레고리) 달력에서 목요일이 들어있는 첫 번째 주입니다. 이것을 주 번호 1이라고 하며, 그 목요일의 ISO 연도는 그레고리 연도와 같습니다.

예를 들어, 2004년은 목요일에 시작되므로, ISO 연도 2004의 첫 주는 월요일, 2003년 12월 29일에 시작하고, 일요일, 2004년 1월 4일에 끝납니다:

>>> from datetime import date
>>> date(2003, 12, 29).isocalendar()
datetime.IsoCalendarDate(year=2004, week=1, weekday=1)
>>> date(2004, 1, 4).isocalendar()
datetime.IsoCalendarDate(year=2004, week=1, weekday=7)

버전 3.9에서 변경: 결과가 튜플에서 네임드 튜플로 변경되었습니다.

date.isoformat()

ISO 8601 형식으로 날짜를 나타내는 문자열을 반환합니다, YYYY-MM-DD:

>>> from datetime import date
>>> date(2002, 12, 4).isoformat()
'2002-12-04'

date.__str__()

For a date d, str(d) is equivalent to d.isoformat().

date.ctime()

날짜를 나타내는 문자열을 반환합니다:

>>> from datetime import date
>>> date(2002, 12, 4).ctime()
'Wed Dec  4 00:00:00 2002'

d.ctime()은 다음과:

time.ctime(time.mktime(d.timetuple()))

네이티브 C ctime() 함수(time.ctime()은 호출하지만 date.ctime()은 호출하지 않습니다)가 C 표준을 준수하는 플랫폼에서 동등합니다.

date.strftime(format)

Return a string representing the date, controlled by an explicit format string. Format codes referring to hours, minutes or seconds will see 0 values. See also strftime() and strptime() Behavior and date.isoformat().

date.__format__(format)

Same as date.strftime(). This makes it possible to specify a format string for a date object in formatted string literals and when using str.format(). See also strftime() and strptime() Behavior and date.isoformat().

사용 예: date

이벤트까지 남은 날 수 계산 예:

>>> import time
>>> from datetime import date
>>> today = date.today()
>>> today
datetime.date(2007, 12, 5)
>>> today == date.fromtimestamp(time.time())
True
>>> my_birthday = date(today.year, 6, 24)
>>> if my_birthday < today:
...     my_birthday = my_birthday.replace(year=today.year + 1)
...
>>> my_birthday
datetime.date(2008, 6, 24)
>>> time_to_birthday = abs(my_birthday - today)
>>> time_to_birthday.days
202

date로 작업하는 추가 예:

>>> from datetime import date
>>> d = date.fromordinal(730920) # 730920th day after 1. 1. 0001
>>> d
datetime.date(2002, 3, 11)

>>> # Methods related to formatting string output
>>> d.isoformat()
'2002-03-11'
>>> d.strftime("%d/%m/%y")
'11/03/02'
>>> d.strftime("%A %d. %B %Y")
'Monday 11. March 2002'
>>> d.ctime()
'Mon Mar 11 00:00:00 2002'
>>> 'The {1} is {0:%d}, the {2} is {0:%B}.'.format(d, "day", "month")
'The day is 11, the month is March.'

>>> # Methods for to extracting 'components' under different calendars
>>> t = d.timetuple()
>>> for i in t:
...     print(i)
2002                # year
3                   # month
11                  # day
0
0
0
0                   # weekday (0 = Monday)
70                  # 70th day in the year
-1
>>> ic = d.isocalendar()
>>> for i in ic:
...     print(i)
2002                # ISO year
11                  # ISO week number
1                   # ISO day number ( 1 = Monday )

>>> # A date object is immutable; all operations produce a new object
>>> d.replace(year=2005)
datetime.date(2005, 3, 11)

datetime 객체

datetime 객체는 date 객체와 time 객체의 모든 정보를 포함하는 단일 객체입니다.

date 객체와 마찬가지로, datetime은 현재의 그레고리력을 양방향으로 확장한다고 가정합니다; time 객체와 마찬가지로, datetime은 하루가 정확히 3600*24초인 것으로 가정합니다.

생성자:

class datetime.datetime(year, month, day, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0)

year, month, day 인자는 필수입니다. tzinfo는 None이거나 tzinfo 서브 클래스의 인스턴스일 수 있습니다. 나머지 인자는 다음 범위의 정수이어야 합니다:

MINYEAR <= year <= MAXYEAR,

1 <= month <= 12,

1 <= day <= 주어진 month와 year에서의 날 수,

0 <= hour < 24,

0 <= minute < 60,

0 <= second < 60,

0 <= microsecond < 1000000,

fold in [0, 1].

이 범위를 벗어나는 인자가 주어지면, ValueError가 발생합니다.

버전 3.6에서 변경: Added the fold parameter.

다른 생성자, 모든 클래스 메서드:

classmethod datetime.today()

Return the current local date and time, with tzinfo None.

다음과 동등합니다:

datetime.fromtimestamp(time.time())

now(), fromtimestamp()를 참조하십시오.

이 메서드는 기능적으로 now()와 동등하지만, tz 매개 변수는 없습니다.

classmethod datetime.now(tz=None)

현재의 지역 날짜와 시간을 반환합니다.

선택적 인자 tz가 None이거나 지정되지 않으면, today()와 유사합니다. 하지만, 가능하면 time.time() 타임스탬프를 통해 얻을 수 있는 것보다 더 높은 정밀도를 제공합니다 (예를 들어, C gettimeofday() 함수를 제공하는 플랫폼에서 가능합니다).

tz가 None이 아니면, tzinfo 서브 클래스의 인스턴스여야 하며, 현재 날짜와 시간이 tz의 시간대로 변환됩니다.

이 함수는 today()와 utcnow()보다 선호됩니다.

참고

Subsequent calls to datetime.now() may return the same instant depending on the precision of the underlying clock.

classmethod datetime.utcnow()

tzinfo가 None인 현재 UTC 날짜와 시간을 반환합니다.

이것은 now()와 비슷하지만, 현재의 UTC 날짜와 시간을 나이브 datetime 객체로 반환합니다. 현재 어웨어 UTC datetime은 datetime.now(timezone.utc)를 호출하여 얻을 수 있습니다. now()도 참조하십시오.

경고

나이브 datetime 객체는 많은 datetime 메서드에 의해 지역 시간으로 취급되므로, UTC로 시간을 나타내는 어웨어 datetime을 사용하는 것이 좋습니다. 따라서 UTC로 현재 시간을 나타내는 객체를 만드는 권장 방법은 datetime.now(timezone.utc)를 호출하는 것입니다.

버전 3.12부터 폐지됨: Use datetime.now() with UTC instead.

classmethod datetime.fromtimestamp(timestamp, tz=None)

time.time()가 반환하는 것과 같은, POSIX timestamp에 해당하는 지역 날짜와 시간을 반환합니다. 선택적 인자 tz가 None이거나 지정되지 않으면 timestamp는 플랫폼의 지역 날짜와 시간으로 변환되며, 반환된 datetime 객체는 나이브합니다.

tz가 None이 아니면, tzinfo 서브 클래스의 인스턴스여야 하며, timestamp는 tz의 시간대로 변환됩니다.

timestamp가 플랫폼 C localtime() 이나 gmtime() 함수에서 지원하는 값 범위를 벗어나면 fromtimestamp()가 OverflowError를 발생시킬 수 있고, localtime() 이나 gmtime()이 실패하면 OSError를 발생시킬 수 있습니다. 1970년에서 2038년까지로 제한되는 것이 일반적입니다. 타임스탬프에 윤초 개념을 포함하는 비 POSIX 시스템에서, fromtimestamp()는 윤초를 무시하므로, 1초 차이가 나는 두 개의 타임스탬프가 같은 datetime 객체를 산출할 수 있습니다. 이 방법은 utcfromtimestamp()보다 선호됩니다.

버전 3.3에서 변경: timestamp가 플랫폼 C localtime() 이나 gmtime() 함수에서 지원하는 값 범위를 벗어나면 ValueError 대신 OverflowError를 발생시킵니다. localtime() 이나 gmtime()이 실패하면 ValueError 대신 OSError를 발생시킵니다.

버전 3.6에서 변경: fromtimestamp()는 fold가 1로 설정된 인스턴스를 반환할 수 있습니다.

classmethod datetime.utcfromtimestamp(timestamp)

tzinfo가 None인 POSIX timestamp에 해당하는 UTC datetime을 반환합니다. (결과 객체는 나이브합니다.)

timestamp가 플랫폼 C gmtime() 함수에서 지원하는 값 범위를 벗어나면 OverflowError가 발생하고, gmtime()이 실패하면 OSError가 발생합니다. 1970년에서 2038년까지로 제한되는 것이 일반적입니다.

어웨어 datetime 객체를 얻으려며, fromtimestamp()를 호출하십시오:

datetime.fromtimestamp(timestamp, timezone.utc)

POSIX 호환 플랫폼에서, 다음 표현식과 동등합니다:

datetime(1970, 1, 1, tzinfo=timezone.utc) + timedelta(seconds=timestamp)

단, 후자의 식은 항상 전체 연도 범위를 지원합니다: MINYEAR와 MAXYEAR 사이, 경계 포함.

경고

나이브 datetime 객체는 많은 datetime 메서드에 의해 지역 시간으로 취급되므로. UTC로 시간을 나타내는 어웨어 datetime을 사용하는 것이 좋습니다. 따라서 UTC로 특정 timestamp를 나타내는 객체를 만드는 권장 방법은 datetime.fromtimestamp(timestamp, tz=timezone.utc)를 호출하는 것입니다.

버전 3.3에서 변경: timestamp가 플랫폼 C gmtime() 함수에서 지원하는 값 범위를 벗어나면 ValueError 대신 OverflowError를 발생시킵니다. gmtime()이 실패하면 ValueError 대신 OSError를 발생시킵니다.

버전 3.12부터 폐지됨: Use datetime.fromtimestamp() with UTC instead.

classmethod datetime.fromordinal(ordinal)

역산 그레고리력 서수(ordinal)에 해당하는 datetime을 반환합니다. 1년 1월 1일이 서수 1입니다. 1 <= ordinal <= datetime.max.toordinal()이 아니면 ValueError가 발생합니다. 결과의 hour, minute, second 및 microsecond는 모두 0이고, tzinfo는 None입니다.

classmethod datetime.combine(date, time, tzinfo=time.tzinfo)

Return a new datetime object whose date components are equal to the given date object’s, and whose time components are equal to the given time object’s. If the tzinfo argument is provided, its value is used to set the tzinfo attribute of the result, otherwise the tzinfo attribute of the time argument is used. If the date argument is a datetime object, its time components and tzinfo attributes are ignored.

For any datetime object d, d == datetime.combine(d.date(), d.time(), d.tzinfo).

버전 3.6에서 변경: tzinfo 인자가 추가되었습니다.

classmethod datetime.fromisoformat(date_string)

Return a datetime corresponding to a date_string in any valid ISO 8601 format, with the following exceptions:

Time zone offsets may have fractional seconds.

The T separator may be replaced by any single unicode character.

Fractional hours and minutes are not supported.

Reduced precision dates are not currently supported (YYYY-MM, YYYY).

Extended date representations are not currently supported (±YYYYYY-MM-DD).

Ordinal dates are not currently supported (YYYY-OOO).

예제:

>>> from datetime import datetime
>>> datetime.fromisoformat('2011-11-04')
datetime.datetime(2011, 11, 4, 0, 0)
>>> datetime.fromisoformat('20111104')
datetime.datetime(2011, 11, 4, 0, 0)
>>> datetime.fromisoformat('2011-11-04T00:05:23')
datetime.datetime(2011, 11, 4, 0, 5, 23)
>>> datetime.fromisoformat('2011-11-04T00:05:23Z')
datetime.datetime(2011, 11, 4, 0, 5, 23, tzinfo=datetime.timezone.utc)
>>> datetime.fromisoformat('20111104T000523')
datetime.datetime(2011, 11, 4, 0, 5, 23)
>>> datetime.fromisoformat('2011-W01-2T00:05:23.283')
datetime.datetime(2011, 1, 4, 0, 5, 23, 283000)
>>> datetime.fromisoformat('2011-11-04 00:05:23.283')
datetime.datetime(2011, 11, 4, 0, 5, 23, 283000)
>>> datetime.fromisoformat('2011-11-04 00:05:23.283+00:00')
datetime.datetime(2011, 11, 4, 0, 5, 23, 283000, tzinfo=datetime.timezone.utc)
>>> datetime.fromisoformat('2011-11-04T00:05:23+04:00')
datetime.datetime(2011, 11, 4, 0, 5, 23,
    tzinfo=datetime.timezone(datetime.timedelta(seconds=14400)))

Added in version 3.7.

버전 3.11에서 변경: Previously, this method only supported formats that could be emitted by date.isoformat() or datetime.isoformat().

classmethod datetime.fromisocalendar(year, week, day)

년, 주 및 일로 지정된 ISO 달력 날짜에 해당하는 datetime을 반환합니다. datetime의 날짜가 아닌 구성 요소는 일반적인 기본값으로 채워집니다. 이것은 함수 datetime.isocalendar()의 역입니다.

Added in version 3.8.

classmethod datetime.strptime(date_string, format)

format에 따라 구문 분석된, date_string에 해당하는 datetime를 반환합니다.

If format does not contain microseconds or time zone information, this is equivalent to:

datetime(*(time.strptime(date_string, format)[0:6]))

ValueError is raised if the date_string and format can’t be parsed by time.strptime() or if it returns a value which isn’t a time tuple. See also strftime() and strptime() Behavior and datetime.fromisoformat().

버전 3.13에서 변경: If format specifies a day of month without a year a DeprecationWarning is now emitted. This is to avoid a quadrennial leap year bug in code seeking to parse only a month and day as the default year used in absence of one in the format is not a leap year. Such format values may raise an error as of Python 3.15. The workaround is to always include a year in your format. If parsing date_string values that do not have a year, explicitly add a year that is a leap year before parsing:

>>> from datetime import datetime
>>> date_string = "02/29"
>>> when = datetime.strptime(f"{date_string};1984", "%m/%d;%Y")  # Avoids leap year bug.
>>> when.strftime("%B %d")
'February 29'

클래스 어트리뷰트:

datetime.min

표현 가능한 가장 이른 datetime, datetime(MINYEAR, 1, 1, tzinfo=None).

datetime.max

표현 가능한 가장 늦은 datetime, datetime(MAXYEAR, 12, 31, 23, 59, 59, 999999, tzinfo=None).

datetime.resolution

같지 않은 datetime 객체 간의 가능한 가장 작은 차이, timedelta(microseconds=1).

인스턴스 어트리뷰트 (읽기 전용):

datetime.year

MINYEAR와 MAXYEAR 사이, 경계 포함.

datetime.month

1과 12 사이, 경계 포함.

datetime.day

1과 주어진 year의 주어진 month의 날 수 사이.

datetime.hour

범위 range(24).

datetime.minute

범위 range(60).

datetime.second

범위 range(60).

datetime.microsecond

범위 range(1000000).

datetime.tzinfo

datetime 생성자에 tzinfo 인자로 전달된 객체이거나, 전달되지 않았으면 None입니다.

datetime.fold

In [0, 1]. Used to disambiguate wall times during a repeated interval. (A repeated interval occurs when clocks are rolled back at the end of daylight saving time or when the UTC offset for the current zone is decreased for political reasons.) The values 0 and 1 represent, respectively, the earlier and later of the two moments with the same wall time representation.

Added in version 3.6.

지원되는 연산:

연산

결과

datetime2 = datetime1 + timedelta

(1)

datetime2 = datetime1 - timedelta

(2)

timedelta = datetime1 - datetime2

(3)

datetime1 == datetime2

datetime1 != datetime2

Equality comparison. (4)

datetime1 < datetime2

datetime1 > datetime2

datetime1 <= datetime2

datetime1 >= datetime2

Order comparison. (5)

datetime2 is a duration of timedelta removed from datetime1, moving forward in time if timedelta.days > 0, or backward if timedelta.days < 0. The result has the same tzinfo attribute as the input datetime, and datetime2 - datetime1 == timedelta after. OverflowError is raised if datetime2.year would be smaller than MINYEAR or larger than MAXYEAR. Note that no time zone adjustments are done even if the input is an aware object.

Computes the datetime2 such that datetime2 + timedelta == datetime1. As for addition, the result has the same tzinfo attribute as the input datetime, and no time zone adjustments are done even if the input is aware.

datetime에서 datetime을 빼는 것은 두 피연산자 모두 나이브하거나, 모두 어웨어할 때만 정의됩니다. 하나가 어웨어이고 다른 하나가 나이브면, TypeError가 발생합니다.

If both are naive, or both are aware and have the same tzinfo attribute, the tzinfo attributes are ignored, and the result is a timedelta object t such that datetime2 + t == datetime1. No time zone adjustments are done in this case.

If both are aware and have different tzinfo attributes, a-b acts as if a and b were first converted to naive UTC datetimes. The result is (a.replace(tzinfo=None) - a.utcoffset()) - (b.replace(tzinfo=None) - b.utcoffset()) except that the implementation never overflows.

datetime objects are equal if they represent the same date and time, taking into account the time zone.

Naive and aware datetime objects are never equal.

If both comparands are aware, and have the same tzinfo attribute, the tzinfo and fold attributes are ignored and the base datetimes are compared. If both comparands are aware and have different tzinfo attributes, the comparison acts as comparands were first converted to UTC datetimes except that the implementation never overflows. datetime instances in a repeated interval are never equal to datetime instances in other time zone.

datetime1 is considered less than datetime2 when datetime1 precedes datetime2 in time, taking into account the time zone.

Order comparison between naive and aware datetime objects raises TypeError.

If both comparands are aware, and have the same tzinfo attribute, the tzinfo and fold attributes are ignored and the base datetimes are compared. If both comparands are aware and have different tzinfo attributes, the comparison acts as comparands were first converted to UTC datetimes except that the implementation never overflows.

버전 3.3에서 변경: 어웨어와 나이브 datetime 인스턴스 간의 동등 비교는 TypeError를 발생시키지 않습니다.

버전 3.13에서 변경: Comparison between datetime object and an instance of the date subclass that is not a datetime subclass no longer converts the latter to date, ignoring the time part and the time zone. The default behavior can be changed by overriding the special comparison methods in subclasses.

인스턴스 메서드:

datetime.date()

같은 year, month, day의 date 객체를 반환합니다.

datetime.time()

같은 hour, minute, second, microsecond 및 fold의 time 객체를 반환합니다. tzinfo는 None입니다. 메서드 timetz()도 참조하십시오.

버전 3.6에서 변경: fold 값은 반환된 time 객체에 복사됩니다.

datetime.timetz()

같은 hour, minute, second, microsecond, fold 및 tzinfo 어트리뷰트의 time 객체를 반환합니다. 메서드 time()도 참조하십시오.

버전 3.6에서 변경: fold 값은 반환된 time 객체에 복사됩니다.

datetime.replace(year=self.year, month=self.month, day=self.day, hour=self.hour, minute=self.minute, second=self.second, microsecond=self.microsecond, tzinfo=self.tzinfo, *, fold=0)

키워드 인자로 새로운 값이 주어진 어트리뷰트를 제외하고, 같은 어트리뷰트를 가진 datetime을 반환합니다. tzinfo=None을 지정하면 날짜와 시간 데이터의 변환 없이 어웨어 datetime에서 나이브 datetime을 만들 수 있습니다.

datetime objects are also supported by generic function copy.replace().

버전 3.6에서 변경: Added the fold parameter.

datetime.astimezone(tz=None)

새로운 tzinfo 어트리뷰트 tz를 갖는 datetime 객체를 반환하는데, 결과가 self와 같은 UTC 시간이지만 tz의 지역 시간이 되도록 날짜와 시간 데이터를 조정합니다.

If provided, tz must be an instance of a tzinfo subclass, and its utcoffset() and dst() methods must not return None. If self is naive, it is presumed to represent time in the system time zone.

If called without arguments (or with tz=None) the system local time zone is assumed for the target time zone. The .tzinfo attribute of the converted datetime instance will be set to an instance of timezone with the zone name and offset obtained from the OS.

If self.tzinfo is tz, self.astimezone(tz) is equal to self: no adjustment of date or time data is performed. Else the result is local time in the time zone tz, representing the same UTC time as self: after astz = dt.astimezone(tz), astz - astz.utcoffset() will have the same date and time data as dt - dt.utcoffset().

If you merely want to attach a timezone object tz to a datetime dt without adjustment of date and time data, use dt.replace(tzinfo=tz). If you merely want to remove the timezone object from an aware datetime dt without conversion of date and time data, use dt.replace(tzinfo=None).

기본 tzinfo.fromutc() 메서드는 astimezone()에 의해 반환된 결과에 영향을 주도록 tzinfo 서브 클래스에서 재정의할 수 있습니다. 에러가 발생하는 경우를 무시하고, astimezone()는 다음과 같이 작동합니다:

def astimezone(self, tz):
    if self.tzinfo is tz:
        return self
    # Convert self to UTC, and attach the new timezone object.
    utc = (self - self.utcoffset()).replace(tzinfo=tz)
    # Convert from UTC to tz's local time.
    return tz.fromutc(utc)

버전 3.3에서 변경: 이제 tz를 생략할 수 있습니다.

버전 3.6에서 변경: 이제 astimezone() 메서드는 이제 나이브 인스턴스에서 호출될 수 있는데, 시스템 지역 시간을 나타내는 것으로 간주합니다.

datetime.utcoffset()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.utcoffset(self)를 반환하고, 후자가 None이나 하루 미만의 크기를 가진 timedelta 객체를 반환하지 않으면 예외를 발생시킵니다.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

datetime.dst()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.dst(self)를 반환하고, 후자가 None이나 하루 미만의 크기를 가진 timedelta 객체를 반환하지 않으면 예외를 발생시킵니다.

버전 3.7에서 변경: DST 오프셋은 분 단위로 제한되지 않습니다.

datetime.tzname()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.tzname(self)를 반환하고, 후자가 None이나 문자열 객체를 반환하지 않으면 예외를 발생시킵니다.

datetime.timetuple()

time.localtime()이 반환하는 것과 같은 time.struct_time을 반환합니다.

d.timetuple()은 다음과 동등합니다:

time.struct_time((d.year, d.month, d.day,
                  d.hour, d.minute, d.second,
                  d.weekday(), yday, dst))

where yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 is the day number within the current year starting with 1 for January 1st. The tm_isdst flag of the result is set according to the dst() method: tzinfo is None or dst() returns None, tm_isdst is set to -1; else if dst() returns a non-zero value, tm_isdst is set to 1; else tm_isdst is set to 0.

datetime.utctimetuple()

If datetime instance d is naive, this is the same as d.timetuple() except that tm_isdst is forced to 0 regardless of what d.dst() returns. DST is never in effect for a UTC time.

If d is aware, d is normalized to UTC time, by subtracting d.utcoffset(), and a time.struct_time for the normalized time is returned. tm_isdst is forced to 0. Note that an OverflowError may be raised if d.year was MINYEAR or MAXYEAR and UTC adjustment spills over a year boundary.

경고

Because naive datetime objects are treated by many datetime methods as local times, it is preferred to use aware datetimes to represent times in UTC; as a result, using datetime.utctimetuple() may give misleading results. If you have a naive datetime representing UTC, use datetime.replace(tzinfo=timezone.utc) to make it aware, at which point you can use datetime.timetuple().

datetime.toordinal()

날짜의 역산 그레고리력 서수를 반환합니다. self.date().toordinal()과 같습니다.

datetime.timestamp()

datetime 인스턴스에 해당하는 POSIX 타임스탬프를 반환합니다. 반환 값은 time.time()이 반환하는 것과 비슷한 float입니다.

Naive datetime instances are assumed to represent local time and this method relies on the platform C mktime() function to perform the conversion. Since datetime supports wider range of values than mktime() on many platforms, this method may raise OverflowError or OSError for times far in the past or far in the future.

어웨어 datetime 인스턴스의 경우, 반환 값은 다음과 같이 계산됩니다:

(dt - datetime(1970, 1, 1, tzinfo=timezone.utc)).total_seconds()

Added in version 3.3.

버전 3.6에서 변경: timestamp() 메서드는 fold 어트리뷰트를 사용하여 반복되는 구간의 시간을 구분합니다.

참고

There is no method to obtain the POSIX timestamp directly from a naive datetime instance representing UTC time. If your application uses this convention and your system time zone is not set to UTC, you can obtain the POSIX timestamp by supplying tzinfo=timezone.utc:

timestamp = dt.replace(tzinfo=timezone.utc).timestamp()

또는 직접 타임스탬프를 계산할 수 있습니다:

timestamp = (dt - datetime(1970, 1, 1)) / timedelta(seconds=1)

datetime.weekday()

정수로 요일을 반환합니다. 월요일은 0이고 일요일은 6입니다. self.date().weekday()와 같습니다. isoweekday()도 참조하십시오.

datetime.isoweekday()

정수로 요일을 반환합니다. 월요일은 1이고 일요일은 7입니다. self.date().isoweekday() 와 같습니다. weekday(), isocalendar()도 참조하십시오.

datetime.isocalendar()

세 개의 컴포넌트를 가진 네임드 튜플을 반환합니다: year, week 및 weekday. self.date().isocalendar()와 같습니다.

datetime.isoformat(sep='T', timespec='auto')

ISO 8601 형식으로 날짜와 시간을 나타내는 문자열을 반환합니다:

YYYY-MM-DDTHH:MM:SS.ffffff, microsecond가 0이 아니면

YYYY-MM-DDTHH:MM:SS, microsecond가 0이면

utcoffset()이 None을 반환하지 않으면, UTC 오프셋을 제공하는 문자열을 덧붙입니다:

YYYY-MM-DDTHH:MM:SS.ffffff+HH:MM[:SS[.ffffff]], microsecond가 0이 아니면

YYYY-MM-DDTHH:MM:SS+HH:MM[:SS[.ffffff]], microsecond가 0이면

예제:

>>> from datetime import datetime, timezone
>>> datetime(2019, 5, 18, 15, 17, 8, 132263).isoformat()
'2019-05-18T15:17:08.132263'
>>> datetime(2019, 5, 18, 15, 17, tzinfo=timezone.utc).isoformat()
'2019-05-18T15:17:00+00:00'

선택적 인자 sep(기본값 'T')은 한 문자 구분자로, 결과의 날짜와 시간 부분 사이에 배치됩니다. 예를 들어:

>>> from datetime import tzinfo, timedelta, datetime
>>> class TZ(tzinfo):
...     """A time zone with an arbitrary, constant -06:39 offset."""
...     def utcoffset(self, dt):
...         return timedelta(hours=-6, minutes=-39)
...
>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
'2002-12-25 00:00:00-06:39'
>>> datetime(2009, 11, 27, microsecond=100, tzinfo=TZ()).isoformat()
'2009-11-27T00:00:00.000100-06:39'

선택적 인자 timespec은 포함할 시간의 추가 구성 요소 수를 지정합니다 (기본값은 'auto'입니다). 다음 중 하나일 수 있습니다:

'auto': microsecond가 0이면 'seconds'와 같고, 그렇지 않으면 'microseconds'와 같습니다.

'hours': hour를 두 자리 숫자 HH 형식으로 포함합니다.

'minutes': hour와 minute를 HH:MM 형식으로 포함합니다.

'seconds': hour, minute 및 second를 HH:MM:SS 형식으로 포함합니다.

'milliseconds': 전체 시간을 포함하지만, 초 미만은 밀리초 단위로 자릅니다. HH:MM:SS.sss 형식입니다.

'microseconds': 전체 시간을 HH:MM:SS.ffffff 형식으로 포함합니다.

참고

제외된 시간 구성 요소는 반올림되지 않고 잘립니다.

잘못된 timespec 인자는 ValueError를 발생시킵니다:

>>> from datetime import datetime
>>> datetime.now().isoformat(timespec='minutes')
'2002-12-25T00:00'
>>> dt = datetime(2015, 1, 1, 12, 30, 59, 0)
>>> dt.isoformat(timespec='microseconds')
'2015-01-01T12:30:59.000000'

버전 3.6에서 변경: Added the timespec parameter.

datetime.__str__()

For a datetime instance d, str(d) is equivalent to d.isoformat(' ').

datetime.ctime()

날짜와 시간을 나타내는 문자열을 반환합니다:

>>> from datetime import datetime
>>> datetime(2002, 12, 4, 20, 30, 40).ctime()
'Wed Dec  4 20:30:40 2002'

출력 문자열은 입력이 어웨어인지 나이브인지와 관계없이 시간대 정보를 포함하지 않습니다.

d.ctime()은 다음과:

time.ctime(time.mktime(d.timetuple()))

네이티브 C ctime() 함수(time.ctime()이 호출하지만, datetime.ctime()은 호출하지 않습니다)가 C 표준을 준수하는 플랫폼에서 동등합니다.

datetime.strftime(format)

Return a string representing the date and time, controlled by an explicit format string. See also strftime() and strptime() Behavior and datetime.isoformat().

datetime.__format__(format)

Same as datetime.strftime(). This makes it possible to specify a format string for a datetime object in formatted string literals and when using str.format(). See also strftime() and strptime() Behavior and datetime.isoformat().

사용 예: datetime

Examples of working with datetime objects:

>>> from datetime import datetime, date, time, timezone

>>> # Using datetime.combine()
>>> d = date(2005, 7, 14)
>>> t = time(12, 30)
>>> datetime.combine(d, t)
datetime.datetime(2005, 7, 14, 12, 30)

>>> # Using datetime.now()
>>> datetime.now()
datetime.datetime(2007, 12, 6, 16, 29, 43, 79043)   # GMT +1
>>> datetime.now(timezone.utc)
datetime.datetime(2007, 12, 6, 15, 29, 43, 79060, tzinfo=datetime.timezone.utc)

>>> # Using datetime.strptime()
>>> dt = datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M")
>>> dt
datetime.datetime(2006, 11, 21, 16, 30)

>>> # Using datetime.timetuple() to get tuple of all attributes
>>> tt = dt.timetuple()
>>> for it in tt:
...     print(it)
...
2006    # year
11      # month
21      # day
16      # hour
30      # minute
0       # second
1       # weekday (0 = Monday)
325     # number of days since 1st January
-1      # dst - method tzinfo.dst() returned None

>>> # Date in ISO format
>>> ic = dt.isocalendar()
>>> for it in ic:
...     print(it)
...
2006    # ISO year
47      # ISO week
2       # ISO weekday

>>> # Formatting a datetime
>>> dt.strftime("%A, %d. %B %Y %I:%M%p")
'Tuesday, 21. November 2006 04:30PM'
>>> 'The {1} is {0:%d}, the {2} is {0:%B}, the {3} is {0:%I:%M%p}.'.format(dt, "day", "month", "time")
'The day is 21, the month is November, the time is 04:30PM.'

아래 예제는 1945년까지 +4 UTC를 사용한 후 +4:30 UTC로 변경한 아프가니스탄 카불의 시간대 정보를 캡처하는 tzinfo 서브 클래스를 정의합니다:

from datetime import timedelta, datetime, tzinfo, timezone

class KabulTz(tzinfo):
    # Kabul used +4 until 1945, when they moved to +4:30
    UTC_MOVE_DATE = datetime(1944, 12, 31, 20, tzinfo=timezone.utc)

    def utcoffset(self, dt):
        if dt.year < 1945:
            return timedelta(hours=4)
        elif (1945, 1, 1, 0, 0) <= dt.timetuple()[:5] < (1945, 1, 1, 0, 30):
            # An ambiguous ("imaginary") half-hour range representing
            # a 'fold' in time due to the shift from +4 to +4:30.
            # If dt falls in the imaginary range, use fold to decide how
            # to resolve. See PEP495.
            return timedelta(hours=4, minutes=(30 if dt.fold else 0))
        else:
            return timedelta(hours=4, minutes=30)

    def fromutc(self, dt):
        # Follow same validations as in datetime.tzinfo
        if not isinstance(dt, datetime):
            raise TypeError("fromutc() requires a datetime argument")
        if dt.tzinfo is not self:
            raise ValueError("dt.tzinfo is not self")

        # A custom implementation is required for fromutc as
        # the input to this function is a datetime with utc values
        # but with a tzinfo set to self.
        # See datetime.astimezone or fromtimestamp.
        if dt.replace(tzinfo=timezone.utc) >= self.UTC_MOVE_DATE:
            return dt + timedelta(hours=4, minutes=30)
        else:
            return dt + timedelta(hours=4)

    def dst(self, dt):
        # Kabul does not observe daylight saving time.
        return timedelta(0)

    def tzname(self, dt):
        if dt >= self.UTC_MOVE_DATE:
            return "+04:30"
        return "+04"

위의 KabulTz 사용법:

>>> tz1 = KabulTz()

>>> # Datetime before the change
>>> dt1 = datetime(1900, 11, 21, 16, 30, tzinfo=tz1)
>>> print(dt1.utcoffset())
4:00:00

>>> # Datetime after the change
>>> dt2 = datetime(2006, 6, 14, 13, 0, tzinfo=tz1)
>>> print(dt2.utcoffset())
4:30:00

>>> # Convert datetime to another time zone
>>> dt3 = dt2.astimezone(timezone.utc)
>>> dt3
datetime.datetime(2006, 6, 14, 8, 30, tzinfo=datetime.timezone.utc)
>>> dt2
datetime.datetime(2006, 6, 14, 13, 0, tzinfo=KabulTz())
>>> dt2 == dt3
True

time 객체

A time object represents a (local) time of day, independent of any particular day, and subject to adjustment via a tzinfo object.

class datetime.time(hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0)

모든 인자는 선택적입니다. tzinfo는 None, 또는 tzinfo 서브 클래스의 인스턴스일 수 있습니다. 나머지 인자는 다음 범위의 정수이어야 합니다:

0 <= hour < 24,

0 <= minute < 60,

0 <= second < 60,

0 <= microsecond < 1000000,

fold in [0, 1].

If an argument outside those ranges is given, ValueError is raised. All default to 0 except tzinfo, which defaults to None.

클래스 어트리뷰트:

time.min

표현 가능한 가장 이른 time, time(0, 0, 0, 0).

time.max

표현 가능한 가장 늦은 time, time(23, 59, 59, 999999).

time.resolution

같지 않은 time 객체 간의 가능한 가장 작은 차이, timedelta(microseconds=1), 하지만 time 객체에 대한 산술은 지원되지 않습니다.

인스턴스 어트리뷰트 (읽기 전용):

time.hour

범위 range(24).

time.minute

범위 range(60).

time.second

범위 range(60).

time.microsecond

범위 range(1000000).

time.tzinfo

time 생성자에 tzinfo 인자로 전달된 객체이거나, 전달되지 않았으면 None입니다.

time.fold

In [0, 1]. Used to disambiguate wall times during a repeated interval. (A repeated interval occurs when clocks are rolled back at the end of daylight saving time or when the UTC offset for the current zone is decreased for political reasons.) The values 0 and 1 represent, respectively, the earlier and later of the two moments with the same wall time representation.

Added in version 3.6.

time objects support equality and order comparisons, where a is considered less than b when a precedes b in time.

Naive and aware time objects are never equal. Order comparison between naive and aware time objects raises TypeError.

If both comparands are aware, and have the same tzinfo attribute, the tzinfo and fold attributes are ignored and the base times are compared. If both comparands are aware and have different tzinfo attributes, the comparands are first adjusted by subtracting their UTC offsets (obtained from self.utcoffset()).

버전 3.3에서 변경: Equality comparisons between aware and naive time instances don’t raise TypeError.

불리언 문맥에서, time 객체는 항상 참으로 간주합니다.

버전 3.5에서 변경: 파이썬 3.5 이전에, time 객체는 UTC 자정을 나타낼 때 거짓으로 간주했습니다. 이 동작은 애매하고 에러가 발생하기 쉬운 것으로 간주하여 파이썬 3.5에서 제거되었습니다. 자세한 내용은 bpo-13936 [https://bugs.python.org/issue?@action=redirect&bpo=13936]을 참조하십시오.

Other constructors:

classmethod time.fromisoformat(time_string)

Return a time corresponding to a time_string in any valid ISO 8601 format, with the following exceptions:

Time zone offsets may have fractional seconds.

The leading T, normally required in cases where there may be ambiguity between a date and a time, is not required.

Fractional seconds may have any number of digits (anything beyond 6 will be truncated).

Fractional hours and minutes are not supported.

Examples:

>>> from datetime import time
>>> time.fromisoformat('04:23:01')
datetime.time(4, 23, 1)
>>> time.fromisoformat('T04:23:01')
datetime.time(4, 23, 1)
>>> time.fromisoformat('T042301')
datetime.time(4, 23, 1)
>>> time.fromisoformat('04:23:01.000384')
datetime.time(4, 23, 1, 384)
>>> time.fromisoformat('04:23:01,000384')
datetime.time(4, 23, 1, 384)
>>> time.fromisoformat('04:23:01+04:00')
datetime.time(4, 23, 1, tzinfo=datetime.timezone(datetime.timedelta(seconds=14400)))
>>> time.fromisoformat('04:23:01Z')
datetime.time(4, 23, 1, tzinfo=datetime.timezone.utc)
>>> time.fromisoformat('04:23:01+00:00')
datetime.time(4, 23, 1, tzinfo=datetime.timezone.utc)

Added in version 3.7.

버전 3.11에서 변경: Previously, this method only supported formats that could be emitted by time.isoformat().

classmethod time.strptime(date_string, format)

Return a time corresponding to date_string, parsed according to format.

If format does not contain microseconds or timezone information, this is equivalent to:

time(*(time.strptime(date_string, format)[3:6]))

ValueError is raised if the date_string and format cannot be parsed by time.strptime() or if it returns a value which is not a time tuple. See also strftime() and strptime() Behavior and time.fromisoformat().

Added in version 3.14.

인스턴스 메서드:

time.replace(hour=self.hour, minute=self.minute, second=self.second, microsecond=self.microsecond, tzinfo=self.tzinfo, *, fold=0)

키워드 인자로 새로운 값이 주어진 어트리뷰트를 제외하고, 같은 값을 가진 time을 반환합니다. tzinfo=None을 지정하면 시간 데이터의 변환 없이 어웨어 time에서 나이브 time을 만들 수 있습니다.

time objects are also supported by generic function copy.replace().

버전 3.6에서 변경: Added the fold parameter.

time.isoformat(timespec='auto')

ISO 8601 형식으로 시간을 나타내는 문자열을 반환합니다, 다음 중 한가지입니다:

HH:MM:SS.ffffff, microsecond가 0이 아니면

HH:MM:SS, microsecond가 0이면

HH:MM:SS.ffffff+HH:MM[:SS[.ffffff]], utcoffset()이 None을 반환하지 않으면

HH:MM:SS+HH:MM[:SS[.ffffff]], microsecond가 0이고 utcoffset()이 None을 반환하지 않으면

선택적 인자 timespec은 포함할 시간의 추가 구성 요소 수를 지정합니다 (기본값은 'auto'입니다). 다음 중 하나일 수 있습니다:

'auto': microsecond가 0이면 'seconds'와 같고, 그렇지 않으면 'microseconds'와 같습니다.

'hours': hour를 두 자리 숫자 HH 형식으로 포함합니다.

'minutes': hour와 minute를 HH:MM 형식으로 포함합니다.

'seconds': hour, minute 및 second를 HH:MM:SS 형식으로 포함합니다.

'milliseconds': 전체 시간을 포함하지만, 초 미만은 밀리초 단위로 자릅니다. HH:MM:SS.sss 형식입니다.

'microseconds': 전체 시간을 HH:MM:SS.ffffff 형식으로 포함합니다.

참고

제외된 시간 구성 요소는 반올림되지 않고 잘립니다.

잘못된 timespec 인자는 ValueError를 발생시킵니다.

예제:

>>> from datetime import time
>>> time(hour=12, minute=34, second=56, microsecond=123456).isoformat(timespec='minutes')
'12:34'
>>> dt = time(hour=12, minute=34, second=56, microsecond=0)
>>> dt.isoformat(timespec='microseconds')
'12:34:56.000000'
>>> dt.isoformat(timespec='auto')
'12:34:56'

버전 3.6에서 변경: Added the timespec parameter.

time.__str__()

For a time t, str(t) is equivalent to t.isoformat().

time.strftime(format)

Return a string representing the time, controlled by an explicit format string. See also strftime() and strptime() Behavior and time.isoformat().

time.__format__(format)

Same as time.strftime(). This makes it possible to specify a format string for a time object in formatted string literals and when using str.format(). See also strftime() and strptime() Behavior and time.isoformat().

time.utcoffset()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.utcoffset(None)를 반환하고, 후자가 None이나 하루 미만의 크기를 가진 timedelta 객체를 반환하지 않으면 예외를 발생시킵니다.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

time.dst()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.dst(None)를 반환하고, 후자가 None이나 하루 미만의 크기를 가진 timedelta 객체를 반환하지 않으면 예외를 발생시킵니다.

버전 3.7에서 변경: DST 오프셋은 분 단위로 제한되지 않습니다.

time.tzname()

tzinfo가 None이면, None을 반환하고, 그렇지 않으면 self.tzinfo.tzname(None)를 반환하고, 후자가 None이나 문자열 객체를 반환하지 않으면 예외를 발생시킵니다.

사용 예: time

time 객체로 작업하는 예제:

>>> from datetime import time, tzinfo, timedelta
>>> class TZ1(tzinfo):
...     def utcoffset(self, dt):
...         return timedelta(hours=1)
...     def dst(self, dt):
...         return timedelta(0)
...     def tzname(self,dt):
...         return "+01:00"
...     def  __repr__(self):
...         return f"{self.__class__.__name__}()"
...
>>> t = time(12, 10, 30, tzinfo=TZ1())
>>> t
datetime.time(12, 10, 30, tzinfo=TZ1())
>>> t.isoformat()
'12:10:30+01:00'
>>> t.dst()
datetime.timedelta(0)
>>> t.tzname()
'+01:00'
>>> t.strftime("%H:%M:%S %Z")
'12:10:30 +01:00'
>>> 'The {} is {:%H:%M}.'.format("time", t)
'The time is 12:10.'

tzinfo 객체

class datetime.tzinfo

이것은 추상 베이스 클래스입니다. 즉, 이 클래스를 직접 인스턴스로 만들면 안 됩니다. 특정 시간대에 대한 정보를 캡처하려면 tzinfo의 서브 클래스를 정의하십시오.

tzinfo의 (구상 서브 클래스의) 인스턴스는 datetime과 time 객체의 생성자에 전달될 수 있습니다. 이 객체들은 자신의 어트리뷰트를 지역 시간으로 간주하며, tzinfo 객체는 지역 시간의 UTC로부터의 오프셋, 시간대 이름 및 DST 오프셋을 모두 전달된 날짜나 시간 객체에 상대적으로 얻는 메서드들을 지원합니다.

You need to derive a concrete subclass, and (at least) supply implementations of the standard tzinfo methods needed by the datetime methods you use. The datetime module provides timezone, a simple concrete subclass of tzinfo which can represent time zones with fixed offset from UTC such as UTC itself or North American EST and EDT.

Special requirement for pickling: A tzinfo subclass must have an __init__() method that can be called with no arguments, otherwise it can be pickled but possibly not unpickled again. This is a technical requirement that may be relaxed in the future.

A concrete subclass of tzinfo may need to implement the following methods. Exactly which methods are needed depends on the uses made of aware datetime objects. If in doubt, simply implement all of them.

tzinfo.utcoffset(dt)

지역 시간의 UTC로부터의 오프셋을 UTC의 동쪽에 있을 때 양의 값을 갖는 timedelta 객체로 반환합니다. 지역 시간이 UTC의 서쪽이면 이 값은 음수여야 합니다.

이것은 UTC로부터의 총 오프셋을 나타냅니다; 예를 들어, tzinfo 객체가 시간대와 DST 조정을 모두 나타내면, utcoffset()은 그들의 합계를 반환해야 합니다. UTC 오프셋을 알 수 없으면, None을 반환합니다. 그렇지 않으면 반환되는 값은 반드시 -timedelta(hours=24)와 timedelta(hours=24) 사이의 timedelta 객체여야 합니다 (오프셋의 크기는 하루 미만이어야 합니다). utcoffset()의 대부분 구현은 아마도 이 두 가지 중 하나일 것입니다:

return CONSTANT                 # fixed-offset class
return CONSTANT + self.dst(dt)  # daylight-aware class

utcoffset()이 None을 반환하지 않으면, dst()도 None을 반환하지 않아야 합니다.

utcoffset()의 기본 구현은 NotImplementedError를 발생시킵니다.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

tzinfo.dst(dt)

일광 절약 시간 (DST) 조정을 timedelta 객체로, 또는 DST 정보를 모르면 None을 반환합니다.

Return timedelta(0) if DST is not in effect. If DST is in effect, return the offset as a timedelta object (see utcoffset() for details). Note that DST offset, if applicable, has already been added to the UTC offset returned by utcoffset(), so there’s no need to consult dst() unless you’re interested in obtaining DST info separately. For example, datetime.timetuple() calls its tzinfo attribute’s dst() method to determine how the tm_isdst flag should be set, and tzinfo.fromutc() calls dst() to account for DST changes when crossing time zones.

표준과 일광 절약 시간을 모두 모형화하는 tzinfo 서브 클래스의 인스턴스 tz는 다음과 같은 의미에서 일관되어야 합니다:

tz.utcoffset(dt) - tz.dst(dt)

must return the same result for every datetime dt with dt.tzinfo == tz. For sane tzinfo subclasses, this expression yields the time zone’s “standard offset”, which should not depend on the date or the time, but only on geographic location. The implementation of datetime.astimezone() relies on this, but cannot detect violations; it’s the programmer’s responsibility to ensure it. If a tzinfo subclass cannot guarantee this, it may be able to override the default implementation of tzinfo.fromutc() to work correctly with astimezone() regardless.

dst()의 대부분 구현은 아마도 이 두 가지 중 하나일 것입니다:

def dst(self, dt):
    # a fixed-offset class:  doesn't account for DST
    return timedelta(0)

또는:

def dst(self, dt):
    # Code to set dston and dstoff to the time zone's DST
    # transition times based on the input dt.year, and expressed
    # in standard local time.

    if dston <= dt.replace(tzinfo=None) < dstoff:
        return timedelta(hours=1)
    else:
        return timedelta(0)

dst()의 기본 구현은 NotImplementedError를 발생시킵니다.

버전 3.7에서 변경: DST 오프셋은 분 단위로 제한되지 않습니다.

tzinfo.tzname(dt)

Return the time zone name corresponding to the datetime object dt, as a string. Nothing about string names is defined by the datetime module, and there’s no requirement that it mean anything in particular. For example, "GMT", "UTC", "-500", "-5:00", "EDT", "US/Eastern", "America/New York" are all valid replies. Return None if a string name isn’t known. Note that this is a method rather than a fixed string primarily because some tzinfo subclasses will wish to return different names depending on the specific value of dt passed, especially if the tzinfo class is accounting for daylight time.

tzname()의 기본 구현은 NotImplementedError를 발생시킵니다.

이 메서드들은 datetime나 time 객체에서 같은 이름의 메서드에 대한 응답으로 호출됩니다. datetime 객체는 자신을 인자로 전달하고, time 객체는 인자로 None을 전달합니다. 따라서 tzinfo 서브 클래스의 메서드는 None이나 datetime 클래스의 dt 인자를 받아들일 준비가 되어 있어야 합니다.

None이 전달되면, 최선의 응답을 결정하는 것은 클래스 설계자에게 달려있습니다. 예를 들어, 클래스가 tzinfo 프로토콜에 time 객체가 참여하지 않는다고 말하고 싶다면 None을 반환하는 것이 적절합니다. 표준 오프셋을 발견하는 다른 규칙이 없으므로, utcoffset(None)이 표준 UTC 오프셋을 반환하는 것이 더 유용할 수 있습니다.

When a datetime object is passed in response to a datetime method, dt.tzinfo is the same object as self. tzinfo methods can rely on this, unless user code calls tzinfo methods directly. The intent is that the tzinfo methods interpret dt as being in local time, and not need worry about objects in other time zones.

서브 클래스가 재정의할 수 있는 tzinfo 메서드가 하나 더 있습니다:

tzinfo.fromutc(dt)

This is called from the default datetime.astimezone() implementation. When called from that, dt.tzinfo is self, and dt’s date and time data are to be viewed as expressing a UTC time. The purpose of fromutc() is to adjust the date and time data, returning an equivalent datetime in self’s local time.

Most tzinfo subclasses should be able to inherit the default fromutc() implementation without problems. It’s strong enough to handle fixed-offset time zones, and time zones accounting for both standard and daylight time, and the latter even if the DST transition times differ in different years. An example of a time zone the default fromutc() implementation may not handle correctly in all cases is one where the standard offset (from UTC) depends on the specific date and time passed, which can happen for political reasons. The default implementations of astimezone() and fromutc() may not produce the result you want if the result is one of the hours straddling the moment the standard offset changes.

에러가 발생하는 경우를 위한 코드를 생략하면, 기본 fromutc() 구현은 다음과 같이 동작합니다:

def fromutc(self, dt):
    # raise ValueError error if dt.tzinfo is not self
    dtoff = dt.utcoffset()
    dtdst = dt.dst()
    # raise ValueError if dtoff is None or dtdst is None
    delta = dtoff - dtdst  # this is self's standard offset
    if delta:
        dt += delta   # convert to standard local time
        dtdst = dt.dst()
        # raise ValueError if dtdst is None
    if dtdst:
        return dt + dtdst
    else:
        return dt

다음 tzinfo_examples.py 파일에는 tzinfo 클래스의 몇 가지 예가 나와 있습니다:

from datetime import tzinfo, timedelta, datetime

ZERO = timedelta(0)
HOUR = timedelta(hours=1)
SECOND = timedelta(seconds=1)

# A class capturing the platform's idea of local time.
# (May result in wrong values on historical times in
#  timezones where UTC offset and/or the DST rules had
#  changed in the past.)
import time as _time

STDOFFSET = timedelta(seconds = -_time.timezone)
if _time.daylight:
    DSTOFFSET = timedelta(seconds = -_time.altzone)
else:
    DSTOFFSET = STDOFFSET

DSTDIFF = DSTOFFSET - STDOFFSET

class LocalTimezone(tzinfo):

    def fromutc(self, dt):
        assert dt.tzinfo is self
        stamp = (dt - datetime(1970, 1, 1, tzinfo=self)) // SECOND
        args = _time.localtime(stamp)[:6]
        dst_diff = DSTDIFF // SECOND
        # Detect fold
        fold = (args == _time.localtime(stamp - dst_diff))
        return datetime(*args, microsecond=dt.microsecond,
                        tzinfo=self, fold=fold)

    def utcoffset(self, dt):
        if self._isdst(dt):
            return DSTOFFSET
        else:
            return STDOFFSET

    def dst(self, dt):
        if self._isdst(dt):
            return DSTDIFF
        else:
            return ZERO

    def tzname(self, dt):
        return _time.tzname[self._isdst(dt)]

    def _isdst(self, dt):
        tt = (dt.year, dt.month, dt.day,
              dt.hour, dt.minute, dt.second,
              dt.weekday(), 0, 0)
        stamp = _time.mktime(tt)
        tt = _time.localtime(stamp)
        return tt.tm_isdst > 0

Local = LocalTimezone()

# A complete implementation of current DST rules for major US time zones.

def first_sunday_on_or_after(dt):
    days_to_go = 6 - dt.weekday()
    if days_to_go:
        dt += timedelta(days_to_go)
    return dt

# US DST Rules
#
# This is a simplified (i.e., wrong for a few cases) set of rules for US
# DST start and end times. For a complete and up-to-date set of DST rules
# and timezone definitions, visit the Olson Database (or try pytz):
# http://www.twinsun.com/tz/tz-link.htm
# https://sourceforge.net/projects/pytz/ (might not be up-to-date)
#
# In the US, since 2007, DST starts at 2am (standard time) on the second
# Sunday in March, which is the first Sunday on or after Mar 8.
DSTSTART_2007 = datetime(1, 3, 8, 2)
# and ends at 2am (DST time) on the first Sunday of Nov.
DSTEND_2007 = datetime(1, 11, 1, 2)
# From 1987 to 2006, DST used to start at 2am (standard time) on the first
# Sunday in April and to end at 2am (DST time) on the last
# Sunday of October, which is the first Sunday on or after Oct 25.
DSTSTART_1987_2006 = datetime(1, 4, 1, 2)
DSTEND_1987_2006 = datetime(1, 10, 25, 2)
# From 1967 to 1986, DST used to start at 2am (standard time) on the last
# Sunday in April (the one on or after April 24) and to end at 2am (DST time)
# on the last Sunday of October, which is the first Sunday
# on or after Oct 25.
DSTSTART_1967_1986 = datetime(1, 4, 24, 2)
DSTEND_1967_1986 = DSTEND_1987_2006

def us_dst_range(year):
    # Find start and end times for US DST. For years before 1967, return
    # start = end for no DST.
    if 2006 < year:
        dststart, dstend = DSTSTART_2007, DSTEND_2007
    elif 1986 < year < 2007:
        dststart, dstend = DSTSTART_1987_2006, DSTEND_1987_2006
    elif 1966 < year < 1987:
        dststart, dstend = DSTSTART_1967_1986, DSTEND_1967_1986
    else:
        return (datetime(year, 1, 1), ) * 2

    start = first_sunday_on_or_after(dststart.replace(year=year))
    end = first_sunday_on_or_after(dstend.replace(year=year))
    return start, end

class USTimeZone(tzinfo):

    def __init__(self, hours, reprname, stdname, dstname):
        self.stdoffset = timedelta(hours=hours)
        self.reprname = reprname
        self.stdname = stdname
        self.dstname = dstname

    def __repr__(self):
        return self.reprname

    def tzname(self, dt):
        if self.dst(dt):
            return self.dstname
        else:
            return self.stdname

    def utcoffset(self, dt):
        return self.stdoffset + self.dst(dt)

    def dst(self, dt):
        if dt is None or dt.tzinfo is None:
            # An exception may be sensible here, in one or both cases.
            # It depends on how you want to treat them.  The default
            # fromutc() implementation (called by the default astimezone()
            # implementation) passes a datetime with dt.tzinfo is self.
            return ZERO
        assert dt.tzinfo is self
        start, end = us_dst_range(dt.year)
        # Can't compare naive to aware objects, so strip the timezone from
        # dt first.
        dt = dt.replace(tzinfo=None)
        if start + HOUR <= dt < end - HOUR:
            # DST is in effect.
            return HOUR
        if end - HOUR <= dt < end:
            # Fold (an ambiguous hour): use dt.fold to disambiguate.
            return ZERO if dt.fold else HOUR
        if start <= dt < start + HOUR:
            # Gap (a non-existent hour): reverse the fold rule.
            return HOUR if dt.fold else ZERO
        # DST is off.
        return ZERO

    def fromutc(self, dt):
        assert dt.tzinfo is self
        start, end = us_dst_range(dt.year)
        start = start.replace(tzinfo=self)
        end = end.replace(tzinfo=self)
        std_time = dt + self.stdoffset
        dst_time = std_time + HOUR
        if end <= dst_time < end + HOUR:
            # Repeated hour
            return std_time.replace(fold=1)
        if std_time < start or dst_time >= end:
            # Standard time
            return std_time
        if start <= std_time < end - HOUR:
            # Daylight saving time
            return dst_time

Eastern  = USTimeZone(-5, "Eastern",  "EST", "EDT")
Central  = USTimeZone(-6, "Central",  "CST", "CDT")
Mountain = USTimeZone(-7, "Mountain", "MST", "MDT")
Pacific  = USTimeZone(-8, "Pacific",  "PST", "PDT")

DST 전환점에서 표준 시간과 일광 절약 시간을 모두 고려하는 tzinfo 서브 클래스에는 일 년에 두 번 불가피한 미묘함이 있음에 유의하십시오. 구체적으로, 3월 두 번째 일요일의 1:59 (EST) 다음 분에 시작하고, 11월 첫 번째 일요일 1:59 (EDT) 다음 분에 끝나는 미국 Eastern(UTC -0500)을 고려하십시오:

  UTC   3:MM  4:MM  5:MM  6:MM  7:MM  8:MM
  EST  22:MM 23:MM  0:MM  1:MM  2:MM  3:MM
  EDT  23:MM  0:MM  1:MM  2:MM  3:MM  4:MM

start  22:MM 23:MM  0:MM  1:MM  3:MM  4:MM

  end  23:MM  0:MM  1:MM  1:MM  2:MM  3:MM

DST가 시작할 때 (“start” 줄), 지역 벽시계는 1:59에서 3:00로 도약합니다. 그날에는 2:MM 형식의 벽 시간은 실질적인 의미가 없으므로, astimezone(Eastern)은 DST가 시작하는 날에 hour == 2인 결과를 전달하지 않습니다. 예를 들어, 2016년 봄의 전진 전환(forward transition)에서, 다음과 같은 결과를 얻습니다:

>>> from datetime import datetime, timezone
>>> from tzinfo_examples import HOUR, Eastern
>>> u0 = datetime(2016, 3, 13, 5, tzinfo=timezone.utc)
>>> for i in range(4):
...     u = u0 + i*HOUR
...     t = u.astimezone(Eastern)
...     print(u.time(), 'UTC =', t.time(), t.tzname())
...
05:00:00 UTC = 00:00:00 EST
06:00:00 UTC = 01:00:00 EST
07:00:00 UTC = 03:00:00 EDT
08:00:00 UTC = 04:00:00 EDT

When DST ends (the “end” line), there’s a potentially worse problem: there’s an hour that can’t be spelled unambiguously in local wall time: the last hour of daylight time. In Eastern, that’s times of the form 5:MM UTC on the day daylight time ends. The local wall clock leaps from 1:59 (daylight time) back to 1:00 (standard time) again. Local times of the form 1:MM are ambiguous. astimezone() mimics the local clock’s behavior by mapping two adjacent UTC hours into the same local hour then. In the Eastern example, UTC times of the form 5:MM and 6:MM both map to 1:MM when converted to Eastern, but earlier times have the fold attribute set to 0 and the later times have it set to 1. For example, at the Fall back transition of 2016, we get:

>>> u0 = datetime(2016, 11, 6, 4, tzinfo=timezone.utc)
>>> for i in range(4):
...     u = u0 + i*HOUR
...     t = u.astimezone(Eastern)
...     print(u.time(), 'UTC =', t.time(), t.tzname(), t.fold)
...
04:00:00 UTC = 00:00:00 EDT 0
05:00:00 UTC = 01:00:00 EDT 0
06:00:00 UTC = 01:00:00 EST 1
07:00:00 UTC = 02:00:00 EST 0

Note that the datetime instances that differ only by the value of the fold attribute are considered equal in comparisons.

Applications that can’t bear wall-time ambiguities should explicitly check the value of the fold attribute or avoid using hybrid tzinfo subclasses; there are no ambiguities when using timezone, or any other fixed-offset tzinfo subclass (such as a class representing only EST (fixed offset -5 hours), or only EDT (fixed offset -4 hours)).

더 보기

zoneinfo

The datetime module has a basic timezone class (for handling arbitrary fixed offsets from UTC) and its timezone.utc attribute (a UTC timezone instance).

zoneinfo brings the IANA time zone database (also known as the Olson database) to Python, and its usage is recommended.

IANA time zone database [https://www.iana.org/time-zones]

시간대 데이터베이스 (종종 tz, tzdata 또는 zoneinfo라고 합니다)에는 전 세계 여러 지역에서 지역 시간의 히스토리를 표현하는 코드와 데이터가 포함되어 있습니다. 정치 단체가 변경 한 시간대 경계, UTC 오프셋 및 일광 절약 시간 규칙을 반영하기 위해 주기적으로 갱신됩니다.

timezone 객체

The timezone class is a subclass of tzinfo, each instance of which represents a time zone defined by a fixed offset from UTC.

Objects of this class cannot be used to represent time zone information in the locations where different offsets are used in different days of the year or where historical changes have been made to civil time.

class datetime.timezone(offset, name=None)

offset 인자는 지역 시간과 UTC 간의 차이를 나타내는 timedelta 객체로 지정해야 합니다. 엄격히(경계를 포함하지 않는) -timedelta(hours=24)와 timedelta(hours=24) 사이여야 합니다. 그렇지 않으면 ValueError가 발생합니다.

name 인자는 선택적입니다. 지정되면 datetime.tzname() 메서드가 반환하는 값으로 사용될 문자열이어야 합니다.

Added in version 3.2.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

timezone.utcoffset(dt)

timezone 인스턴스가 구축될 때 지정된 고정값을 반환합니다.

dt 인자는 무시됩니다. 반환 값은 지역 시간과 UTC 간의 차이와 같은 timedelta 인스턴스입니다.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

timezone.tzname(dt)

timezone 인스턴스가 구축될 때 지정된 고정값을 반환합니다.

name을 생성자에 제공하지 않았으면, tzname(dt)에 의해 반환되는 이름은 다음과 같이 offset 값으로부터 생성됩니다. offset이 timedelta(0)이면, 이름은 “UTC”이고, 그렇지 않으면 문자열 UTC±HH:MM입니다. 여기서 ±는 offset의 부호이고, HH와 MM은 각각 offset.hours와 offset.minutes의 두 자리 숫자입니다.

버전 3.6에서 변경: Name generated from offset=timedelta(0) is now plain 'UTC', not 'UTC+00:00'.

timezone.dst(dt)

항상 None을 반환합니다.

timezone.fromutc(dt)

dt + offset을 반환합니다. dt 인자는 tzinfo가 self로 설정된 어웨어 datetime 인스턴스여야 합니다.

클래스 어트리뷰트:

timezone.utc

The UTC time zone, timezone(timedelta(0)).

strftime() and strptime() Behavior

date, datetime 및 time 객체는 모두 strftime(format) 메서드를 지원하여, 명시적 포맷 문자열로 제어된 시간을 나타내는 문자열을 만듭니다.

Conversely, the date.strptime(), datetime.strptime() and time.strptime() class methods create an object from a string representing the time and a corresponding format string.

The table below provides a high-level comparison of strftime() versus strptime():

strftime

strptime

용도

주어진 포맷에 따라 객체를 문자열로 변환합니다

Parse a string into an object given a corresponding format

메서드의 형

인스턴스 메서드

클래스 메서드

서명

strftime(format)

strptime(date_string, format)

strftime() and strptime() Format Codes

These methods accept format codes that can be used to parse and format dates:

>>> datetime.strptime('31/01/22 23:59:59.999999',
...                   '%d/%m/%y %H:%M:%S.%f')
datetime.datetime(2022, 1, 31, 23, 59, 59, 999999)
>>> _.strftime('%a %d %b %Y, %I:%M%p')
'Mon 31 Jan 2022, 11:59PM'

다음은 1989 C 표준이 요구하는 모든 포맷 코드 목록이며, 표준 C 구현이 있는 모든 플랫폼에서 작동합니다.

지시자

의미

예

노트

%a

요일을 로케일의 축약된 이름으로.

Sun, Mon, …, Sat (en_US);

So, Mo, …, Sa (de_DE)

(1)

%A

요일을 로케일의 전체 이름으로.

Sunday, Monday, …, Saturday (en_US);

Sonntag, Montag, …, Samstag (de_DE)

(1)

%w

요일을 10진수로, 0은 일요일이고 6은 토요일입니다.

0, 1, …, 6

%d

월중 일(day of the month)을 0으로 채워진 10진수로.

01, 02, …, 31

(9)

%b

월을 로케일의 축약된 이름으로.

Jan, Feb, …, Dec (en_US);

Jan, Feb, …, Dez (de_DE)

(1)

%B

월을 로케일의 전체 이름으로.

January, February, …, December (en_US);

Januar, Februar, …, Dezember (de_DE)

(1)

%m

월을 0으로 채워진 10진수로.

01, 02, …, 12

(9)

%y

세기가 없는 해(year)를 0으로 채워진 10진수로.

00, 01, …, 99

(9)

%Y

세기가 있는 해(year)를 10진수로.

0001, 0002, …, 2013, 2014, …, 9998, 9999

(2)

%H

시(24시간제)를 0으로 채워진 십진수로.

00, 01, …, 23

(9)

%I

시(12시간제)를 0으로 채워진 십진수로.

01, 02, …, 12

(9)

%p

로케일의 오전이나 오후에 해당하는 것.

AM, PM (en_US);

am, pm (de_DE)

(1), (3)

%M

분을 0으로 채워진 십진수로.

00, 01, …, 59

(9)

%S

초를 0으로 채워진 10진수로.

00, 01, …, 59

(4), (9)

%f

Microsecond as a decimal number, zero-padded to 6 digits.

000000, 000001, …, 999999

(5)

%z

±HHMM[SS[.ffffff]] 형태의 UTC 오프셋 (객체가 나이브하면 빈 문자열).

(비어 있음), +0000, -0400, +1030, +063415, -030712.345216

(6)

%Z

시간대 이름 (객체가 나이브하면 빈 문자열).

(비어 있음), UTC, GMT

(6)

%j

연중 일(day of the year)을 0으로 채워진 십진수로.

001, 002, …, 366

(9)

%U

Week number of the year (Sunday as the first day of the week) as a zero-padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0.

00, 01, …, 53

(7), (9)

%W

Week number of the year (Monday as the first day of the week) as a zero-padded decimal number. All days in a new year preceding the first Monday are considered to be in week 0.

00, 01, …, 53

(7), (9)

%c

로케일의 적절한 날짜와 시간 표현.

Tue Aug 16 21:30:00 1988 (en_US);

Di 16 Aug 21:30:00 1988 (de_DE)

(1)

%x

로케일의 적절한 날짜 표현.

08/16/88 (None);

08/16/1988 (en_US);

16.08.1988 (de_DE)

(1)

%X

로케일의 적절한 시간 표현.

21:30:00 (en_US);

21:30:00 (de_DE)

(1)

%%

리터럴 '%' 문자.

%

C89 표준에서 요구하지 않는 몇 가지 추가 지시자가 편의상 포함되어 있습니다. 이 파라미터들은 모두 ISO 8601 날짜 값에 해당합니다.

지시자

의미

예

노트

%G

ISO 주(%V)의 더 큰 부분을 포함하는 연도를 나타내는 세기가 있는 ISO 8601 연도.

0001, 0002, …, 2013, 2014, …, 9998, 9999

(8)

%u

ISO 8601 요일을 10진수로, 1은 월요일입니다.

1, 2, …, 7

%V

ISO 8601 주를 월요일을 주의 시작으로 하는 십진수로. 주 01은 1월 4일을 포함하는 주입니다.

01, 02, …, 53

(8), (9)

%:z

UTC offset in the form ±HH:MM[:SS[.ffffff]] (empty string if the object is naive).

(empty), +00:00, -04:00, +10:30, +06:34:15, -03:07:12.345216

(6)

These may not be available on all platforms when used with the strftime() method. The ISO 8601 year and ISO 8601 week directives are not interchangeable with the year and week number directives above. Calling strptime() with incomplete or ambiguous ISO 8601 directives will raise a ValueError.

The full set of format codes supported varies across platforms, because Python calls the platform C library’s strftime() function, and platform variations are common. To see the full set of format codes supported on your platform, consult the strftime(3) [https://manpages.debian.org/strftime(3)] documentation. There are also differences between platforms in handling of unsupported format specifiers.

Added in version 3.6: %G, %u 및 %V가 추가되었습니다.

Added in version 3.12: %:z was added.

기술적 세부 사항

Broadly speaking, d.strftime(fmt) acts like the time module’s time.strftime(fmt, d.timetuple()) although not all objects support a timetuple() method.

For the datetime.strptime() class method, the default value is 1900-01-01T00:00:00.000: any components not specified in the format string will be pulled from the default value. [4]

datetime.strptime(date_string, format)은 다음과 동등합니다:

datetime(*(time.strptime(date_string, format)[0:6]))

except when the format includes sub-second components or time zone offset information, which are supported in datetime.strptime but are discarded by time.strptime.

For time objects, the format codes for year, month, and day should not be used, as time objects have no such values. If they’re used anyway, 1900 is substituted for the year, and 1 for the month and day.

For date objects, the format codes for hours, minutes, seconds, and microseconds should not be used, as date objects have no such values. If they’re used anyway, 0 is substituted for them.

같은 이유로, 현재 로케일의 문자 집합으로는 표현할 수 없는 유니코드 코드 포인트를 포함하는 포맷 문자열의 처리도 플랫폼에 따라 다릅니다. 일부 플랫폼에서는 이러한 코드 포인트가 그대로 출력에 보존되지만, 다른 곳에서는 strftime이 UnicodeError를 발생시키거나 대신 빈 문자열을 반환할 수 있습니다.

노트:

Because the format depends on the current locale, care should be taken when making assumptions about the output value. Field orderings will vary (for example, “month/day/year” versus “day/month/year”), and the output may contain non-ASCII characters.

The strptime() method can parse years in the full [1, 9999] range, but years < 1000 must be zero-filled to 4-digit width.

버전 3.2에서 변경: In previous versions, strftime() method was restricted to years >= 1900.

버전 3.3에서 변경: In version 3.2, strftime() method was restricted to years >= 1000.

When used with the strptime() method, the %p directive only affects the output hour field if the %I directive is used to parse the hour.

Unlike the time module, the datetime module does not support leap seconds.

When used with the strptime() method, the %f directive accepts from one to six digits and zero pads on the right. %f is an extension to the set of format characters in the C standard (but implemented separately in datetime objects, and therefore always available).

For a naive object, the %z, %:z and %Z format codes are replaced by empty strings.

어웨어 객체의 경우:

%z

utcoffset() is transformed into a string of the form ±HHMM[SS[.ffffff]], where HH is a 2-digit string giving the number of UTC offset hours, MM is a 2-digit string giving the number of UTC offset minutes, SS is a 2-digit string giving the number of UTC offset seconds and ffffff is a 6-digit string giving the number of UTC offset microseconds. The ffffff part is omitted when the offset is a whole number of seconds and both the ffffff and the SS part is omitted when the offset is a whole number of minutes. For example, if utcoffset() returns timedelta(hours=-3, minutes=-30), %z is replaced with the string '-0330'.

버전 3.7에서 변경: UTC 오프셋은 분 단위로 제한되지 않습니다.

버전 3.7에서 변경: When the %z directive is provided to the strptime() method, the UTC offsets can have a colon as a separator between hours, minutes and seconds. For example, '+01:00:00' will be parsed as an offset of one hour. In addition, providing 'Z' is identical to '+00:00'.

%:z

Behaves exactly as %z, but has a colon separator added between hours, minutes and seconds.

%Z

In strftime(), %Z is replaced by an empty string if tzname() returns None; otherwise %Z is replaced by the returned value, which must be a string.

strptime() only accepts certain values for %Z:

컴퓨터의 로케일에 대한 time.tzname의 모든 값

하드 코딩된 값 UTC와 GMT

따라서 일본에 거주하는 사람은 JST, UTC 및 GMT를 유효한 값으로 가질 수 있지만, 아마도 EST는 아닙니다. 유효하지 않은 값에 대해서는 ValueError가 발생합니다.

버전 3.2에서 변경: When the %z directive is provided to the strptime() method, an aware datetime object will be produced. The tzinfo of the result will be set to a timezone instance.

When used with the strptime() method, %U and %W are only used in calculations when the day of the week and the calendar year (%Y) are specified.

Similar to %U and %W, %V is only used in calculations when the day of the week and the ISO year (%G) are specified in a strptime() format string. Also note that %G and %Y are not interchangeable.

When used with the strptime() method, the leading zero is optional for formats %d, %m, %H, %I, %M, %S, %j, %U, %W, and %V. Format %y does require a leading zero.

When parsing a month and day using strptime(), always include a year in the format. If the value you need to parse lacks a year, append an explicit dummy leap year. Otherwise your code will raise an exception when it encounters leap day because the default year used by the parser is not a leap year. Users run into this bug every four years…

>>> month_day = "02/29"
>>> datetime.strptime(f"{month_day};1984", "%m/%d;%Y")  # No leap year bug.
datetime.datetime(1984, 2, 29, 0, 0)

Deprecated since version 3.13, will be removed in version 3.15: strptime() calls using a format string containing a day of month without a year now emit a DeprecationWarning. In 3.15 or later we may change this into an error or change the default year to a leap year. See gh-70647 [https://github.com/python/cpython/issues/70647].

각주

[1]

즉, 상대론적 효과를 무시한다면

[2]

이것은 Dershowitz와 Reingold의 책 Calendrical Calculations에 나오는 “역산 그레고리(proleptic Gregorian)” 달력의 정의와 일치합니다. 이 달력은 모든 계산의 기본 달력입니다. 역산 그레고리력 서수(ordinal)와 다른 많은 달력 시스템 사이의 변환을 위한 알고리즘에 관해서는 이 책을 참조하십시오.

[3]

See R. H. van Gent’s guide to the mathematics of the ISO 8601 calendar [https://web.archive.org/web/20220531051136/https://webspace.science.uu.nl/~gent0113/calendar/isocalendar.htm] for a good explanation.

[4]

Passing datetime.strptime('Feb 29', '%b %d') will fail since 1900 is not a leap year.

zoneinfo — IANA time zone support

Added in version 3.9.

Source code: Lib/zoneinfo [https://github.com/python/cpython/tree/main/Lib/zoneinfo]

The zoneinfo module provides a concrete time zone implementation to support the IANA time zone database as originally specified in PEP 615 [https://peps.python.org/pep-0615/]. By default, zoneinfo uses the system’s time zone data if available; if no system time zone data is available, the library will fall back to using the first-party tzdata [https://pypi.org/project/tzdata/] package available on PyPI.

더 보기

모듈: datetime

ZoneInfo 클래스가 사용되도록 설계된 time과 datetime 형을 제공합니다.

Package tzdata [https://pypi.org/project/tzdata/]

PyPI를 통해 시간대 데이터를 제공하기 위해 CPython 핵심 개발자가 유지 보수하는 자사(first-party) 패키지.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

ZoneInfo 사용하기

ZoneInfo는 datetime.tzinfo 추상 베이스 클래스의 구상 구현이며, 생성자, datetime.replace 메서드 또는 datetime.astimezone을 통해 tzinfo에 연결하려는 것입니다:

>>> from zoneinfo import ZoneInfo
>>> from datetime import datetime, timedelta

>>> dt = datetime(2020, 10, 31, 12, tzinfo=ZoneInfo("America/Los_Angeles"))
>>> print(dt)
2020-10-31 12:00:00-07:00

>>> dt.tzname()
'PDT'

이 방식으로 구성된 datetime들은 datetime 산술과 호환되며 추가 개입 없이 일광 절약 시간제 전환을 처리합니다:

>>> dt_add = dt + timedelta(days=1)

>>> print(dt_add)
2020-11-01 12:00:00-08:00

>>> dt_add.tzname()
'PST'

이 시간대는 PEP 495 [https://peps.python.org/pep-0495/]에 도입된 fold 어트리뷰트도 지원합니다. 모호한 시간을 유발하는 오프셋 전환(가령 일광 절약 시간에서 표준 시간으로의 전환) 중, 전환 전의 오프셋이 fold=0일 때 사용되며, 전환 후의 오프셋은 fold=1일 때 사용됩니다, 예를 들어:

>>> dt = datetime(2020, 11, 1, 1, tzinfo=ZoneInfo("America/Los_Angeles"))
>>> print(dt)
2020-11-01 01:00:00-07:00

>>> print(dt.replace(fold=1))
2020-11-01 01:00:00-08:00

다른 시간대에서 변환할 때, fold는 올바른 값으로 설정됩니다:

>>> from datetime import timezone
>>> LOS_ANGELES = ZoneInfo("America/Los_Angeles")
>>> dt_utc = datetime(2020, 11, 1, 8, tzinfo=timezone.utc)

>>> # Before the PDT -> PST transition
>>> print(dt_utc.astimezone(LOS_ANGELES))
2020-11-01 01:00:00-07:00

>>> # After the PDT -> PST transition
>>> print((dt_utc + timedelta(hours=1)).astimezone(LOS_ANGELES))
2020-11-01 01:00:00-08:00

데이터 소스

The zoneinfo module does not directly provide time zone data, and instead pulls time zone information from the system time zone database or the first-party PyPI package tzdata [https://pypi.org/project/tzdata/], if available. Some systems, including notably Windows systems, do not have an IANA database available, and so for projects targeting cross-platform compatibility that require time zone data, it is recommended to declare a dependency on tzdata. If neither system data nor tzdata are available, all calls to ZoneInfo will raise ZoneInfoNotFoundError.

데이터 소스 구성

ZoneInfo(key)가 호출될 때, 생성자는 먼저 TZPATH에 지정된 디렉터리에서 key와 일치하는 파일을 검색하고, 실패하면 tzdata 패키지에서 일치하는 것을 찾습니다. 이 동작은 세 가지 방법으로 구성할 수 있습니다:

달리 지정되지 않을 때의 기본 TZPATH는 컴파일 시간에 구성할 수 있습니다.

TZPATH는 환경 변수를 사용하여 구성할 수 있습니다.

실행 시간에는, reset_tzpath() 함수를 사용하여 검색 경로를 조작할 수 있습니다.

컴파일 시간 구성

The default TZPATH includes several common deployment locations for the time zone database (except on Windows, where there are no “well-known” locations for time zone data). On POSIX systems, downstream distributors and those building Python from source who know where their system time zone data is deployed may change the default time zone path by specifying the compile-time option TZPATH (or, more likely, the configure flag --with-tzpath), which should be a string delimited by os.pathsep.

모든 플랫폼에서, 구성된 값은 sysconfig.get_config_var()에서 TZPATH 키로 사용 가능합니다.

환경 구성

TZPATH를 초기화할 때 (임포트 시점이나 인자 없이 reset_tzpath()가 호출될 때마다) zoneinfo 모듈은 환경 변수 PYTHONTZPATH(있다면)를 사용하여 검색 경로를 설정합니다.

PYTHONTZPATH

사용할 시간대 검색 경로를 포함하는 os.pathsep으로 구분된 문자열입니다. 상대 경로가 아닌 절대 경로로만 구성되어야 합니다. PYTHONTZPATH에 지정된 상대 컴포넌트는 사용되지 않지만, 그 밖의 상대 경로가 지정된 경우의 동작은 구현이 정의합니다; CPython은 InvalidTZPathWarning을 발생시키지만, 다른 구현에서는 잘못된 구성 요소를 조용히 무시하거나 예외를 발생시킬 수 있습니다.

시스템이 시스템 데이터를 무시하고 tzdata 패키지를 대신 사용하도록 설정하려면, PYTHONTZPATH=""를 설정하십시오.

실행 시간 구성

reset_tzpath() 함수를 사용하여 실행 시간에 TZ 검색 경로를 구성할 수도 있습니다. 일반적으로 권장되는 작업은 아닙니다만, 특정 시간대 경로를 사용해야 하는 (또는 시스템 시간대에 대한 액세스를 비활성화해야 하는) 테스트 함수에 사용하는 것은 합리적입니다.

ZoneInfo 클래스

class zoneinfo.ZoneInfo(key)

문자열 key로 지정된 IANA 시간대를 나타내는 구상 datetime.tzinfo 서브 클래스. 기본 생성자에 대한 호출은 항상 동일하다고 비교되는 객체를 반환합니다; 다르게 말하면, ZoneInfo.clear_cache()를 통한 캐시 무효화를 방지한다면, 다음 어서션이 항상 참입니다:

a = ZoneInfo(key)
b = ZoneInfo(key)
assert a is b

key는 상위 수준 참조가 없는 상대적인 정규화된 POSIX 경로의 형식이어야 합니다. 적합하지 않은 key가 전달되면 생성자가 ValueError를 발생시킵니다.

key와 일치하는 파일이 없으면, 생성자는 ZoneInfoNotFoundError를 발생시킵니다.

ZoneInfo 클래스에는 두 개의 대체 생성자가 있습니다:

classmethod ZoneInfo.from_file(fobj, /, key=None)

바이트열을 반환하는 파일류 객체(예를 들어 바이너리 모드로 열린 파일이나 io.BytesIO 객체)에서 ZoneInfo 객체를 생성합니다. 기본 생성자와 달리, 항상 새로운 객체를 생성합니다.

key 매개 변수는 __str__()과 __repr__()를 위해 시간대 이름을 설정합니다.

이 생성자를 통해 만들어진 객체는 피클 할 수 없습니다 (피클 직렬화를 참조하십시오).

classmethod ZoneInfo.no_cache(key)

생성자의 캐시를 우회하는 대체 생성자. 기본 생성자와 동일하지만, 호출마다 새 객체를 반환합니다. 이것은 테스트나 데모 목적으로 유용 할 수 있지만, 다른 캐시 무효화 전략을 갖는 시스템을 만드는 데 사용될 수도 있습니다.

이 생성자를 통해 만들어진 객체는 역 피클 될 때 역 직렬화 프로세스의 캐시도 우회합니다.

조심

이 생성자를 사용하면 예기치 못한 방식으로 날짜 시간의 의미가 변경될 수 있기 때문에, 필요한 경우에만 사용하십시오.

다음과 같은 클래스 메서드도 사용할 수 있습니다:

classmethod ZoneInfo.clear_cache(*, only_keys=None)

ZoneInfo 클래스에서 캐시를 무효로 하는 메서드. 인자가 전달되지 않으면, 모든 캐시가 무효가 되고 각 키의 기본 생성자에 대한 다음 호출은 새 인스턴스를 반환합니다.

키 이름의 이터러블이 only_keys 매개 변수에 전달되면, 지정된 키만 캐시에서 제거됩니다. only_keys에 전달되었지만, 캐시에서 찾을 수 없는 키는 무시됩니다.

경고

Invoking this function may change the semantics of datetimes using ZoneInfo in surprising ways; this modifies module state and thus may have wide-ranging effects. Only use it if you know that you need to.

이 클래스에는 하나의 어트리뷰트가 있습니다:

ZoneInfo.key

이것은 읽기 전용 어트리뷰트이며 생성자에 전달된 key의 값을 반환하는데, IANA 시간대 데이터베이스의 조회 키이어야 합니다 (예를 들어 America/New_York, Europe/Paris 또는 Asia/Tokyo).

key 매개 변수를 지정하지 않고 파일에서 생성된 시간대의 경우, None으로 설정됩니다.

참고

이들을 최종 사용자에게 노출하는 것이 다소 일반적인 관행이지만, 이 값들은 관련 시간대를 나타내는 기본 키로 설계되었을 뿐, 사용자 대면 요소일 필요는 없습니다. CLDR (the Unicode Common Locale Data Repository)과 같은 프로젝트를 사용하면 이러한 키에서 더 사용자 친화적인 문자열을 얻을 수 있습니다.

문자열 표현

ZoneInfo 객체에 대해 str을 호출할 때 반환되는 문자열 표현은 기본적으로 ZoneInfo.key 어트리뷰트를 사용합니다 (어트리뷰트 설명서의 사용법에 관한 참고를 보십시오):

>>> zone = ZoneInfo("Pacific/Kwajalein")
>>> str(zone)
'Pacific/Kwajalein'

>>> dt = datetime(2020, 4, 1, 3, 15, tzinfo=zone)
>>> f"{dt.isoformat()} [{dt.tzinfo}]"
'2020-04-01T03:15:00+12:00 [Pacific/Kwajalein]'

key 매개 변수를 지정하지 않고 파일에서 생성된 객체의 경우, str은 repr() 호출로 대체됩니다. ZoneInfo의 repr은 구현 정의이며 버전 간에 반드시 안정적일 필요는 없지만, 유효한 ZoneInfo 키가 될 수는 없음이 보장됩니다.

피클 직렬화

모든 전환 데이터를 직렬화하는 대신, ZoneInfo 객체는 키로 직렬화되며 파일에서 생성된 ZoneInfo 객체는 (지정된 key 값을 가진 객체조차) 피클 할 수 없습니다.

ZoneInfo 파일의 동작은 파일 생성 방식에 따라 다릅니다:

ZoneInfo(key): 기본 생성자로 생성될 때, ZoneInfo 객체는 키로 직렬화되며, 역 직렬화할 때, 역 직렬화 프로세스는 기본 생성자를 사용해서 같은 시간대에 대한 다른 참조와 같은 객체가 될 것으로 예상됩니다. 예를 들어, europe_berlin_pkl이 ZoneInfo("Europe/Berlin")에서 생성된 피클을 포함하는 문자열이면, 다음과 같은 동작이 예상됩니다:

>>> a = ZoneInfo("Europe/Berlin")
>>> b = pickle.loads(europe_berlin_pkl)
>>> a is b
True

ZoneInfo.no_cache(key): 캐시 우회 생성자에서 생성될 때, 이 ZoneInfo 객체도 키로 직렬화되지만, 역 직렬화할 때, 역 직렬화 프로세스는 캐시 우회 생성자를 사용합니다. europe_berlin_pkl_nc가 ZoneInfo.no_cache("Europe/Berlin")에서 생성된 피클을 포함하는 문자열이면, 다음과 같은 동작이 예상됩니다:

>>> a = ZoneInfo("Europe/Berlin")
>>> b = pickle.loads(europe_berlin_pkl_nc)
>>> a is b
False

ZoneInfo.from_file(fobj, /, key=None): 파일에서 생성될 때, ZoneInfo 객체는 피클 하려고 하면 예외를 발생시킵니다. 최종 사용자가 파일에서 생성된 ZoneInfo를 피클 하길 원하면, 래퍼 형이나 사용자 정의 직렬화 함수를 사용하는 것이 좋습니다: 키로 직렬화하거나 파일 객체의 내용을 저장하고 직렬화합니다.

이 직렬화 방법에서는 직렬화와 역 직렬화 환경 모두에서 클래스와 함수에 대한 참조가 존재해야 하는 방식과 유사하게, 직렬화와 역 직렬화 측 모두에서 필요한 키의 시간대 데이터를 사용할 수 있어야 합니다. 또한 다른 버전의 시간대 데이터가 있는 환경에서 피클링 된 ZoneInfo를 역 피클링 할 때 결과의 일관성에 대해 보장되지 않습니다.

함수

zoneinfo.available_timezones()

시간대 경로의 어느 곳에서건 사용 가능한 IANA 시간대에 유효한 모든 키가 포함된 집합을 가져옵니다. 이것은 함수를 호출할 때마다 다시 계산됩니다.

이 함수는 규범적(canonical) 시간대 이름 만 포함하고 posix/와 right/ 디렉터리에 있는 것이나 posixrules 시간대와 같은 “특수” 시간대는 포함하지 않습니다.

조심

시간대 경로에 있는 파일이 유효한 시간대인지 확인하는 가장 좋은 방법은 시작 부분에 나오는 “매직 문자열”을 읽는 것이라서, 이 함수는 많은 파일을 열 수 있습니다.

참고

이 값은 최종 사용자에게 노출되도록 설계되지 않았습니다; 사용자 대면 요소의 경우, 응용 프로그램은 CLDR (the Unicode Common Locale Data Repository)과 같은 것을 사용하여 더 사용자 친화적인 문자열을 가져와야 합니다. ZoneInfo.key에 있는 주의 사항도 참조하십시오.

zoneinfo.reset_tzpath(to=None)

모듈의 시간대 검색 경로(TZPATH)를 설정하거나 재설정합니다. 인자 없이 호출하면, TZPATH가 기본값으로 설정됩니다.

reset_tzpath를 호출해도 ZoneInfo 캐시가 무효가 되지 않아서, 기본 ZoneInfo 생성자에 대한 호출은 캐시 누락의 경우에만 새 TZPATH를 사용합니다.

to 매개 변수는 문자열이나 os.PathLike의 시퀀스이어야 하며 문자열이 아닙니다. 모두 절대 경로여야 합니다. 절대 경로 이외의 것이 전달되면 ValueError가 발생합니다.

전역

zoneinfo.TZPATH

시간대 검색 경로를 나타내는 읽기 전용 시퀀스 – 키에서 ZoneInfo를 생성할 때, 키는 TZPATH의 각 항목에 결합하며, 발견된 첫 번째 파일이 사용됩니다.

TZPATH는 구성 방법과 관계없이 절대 경로만 포함할 수 있고, 상대 경로는 절대 포함하지 않습니다.

zoneinfo.TZPATH가 가리키는 객체는 reset_tzpath()에 대한 호출에 따라 변경될 수 있어서, zoneinfo에서 TZPATH를 임포트 하거나 수명이 긴 변수에 zoneinfo.TZPATH를 대입하는 대신 zoneinfo.TZPATH를 사용하는 것이 좋습니다.

시간대 검색 경로 구성에 대한 자세한 정보는 데이터 소스 구성을 참조하십시오.

예외와 경고

exception zoneinfo.ZoneInfoNotFoundError

지정된 키를 시스템에서 찾을 수 없어서 ZoneInfo 객체 생성에 실패할 때 발생합니다. 이것은 KeyError의 서브 클래스입니다.

exception zoneinfo.InvalidTZPathWarning

PYTHONTZPATH에 상대 경로와 같이 필터링 될 유효하지 않은 구성 요소가 포함되어있을 때 발생합니다.

calendar — General calendar-related functions

소스 코드: Lib/calendar.py [https://github.com/python/cpython/tree/main/Lib/calendar.py]

이 모듈을 사용하면 유닉스 cal 프로그램과 같은 달력을 출력할 수 있으며, 달력과 관련된 유용한 추가 함수를 제공합니다. 기본적으로, 이 달력은 월요일을 주의 첫째 날로 하고, 일요일을 마지막 날로 합니다 (유럽 관례). 주의 첫째 날을 일요일(6)이나 다른 요일로 설정하려면 setfirstweekday()를 사용하십시오. 날짜를 지정하는 매개 변수는 정수로 제공됩니다. 관련 기능에 대해서는, datetime과 time 모듈도 참조하십시오.

이 모듈에 정의된 함수와 클래스는 이상적인 달력을 사용합니다, 양방향으로 무한정 확장된 현재 그레고리력. 이것은 Dershowitz와 Reingold의 저서 “Calendrical Calculations”에 나오는 “역산 그레고리(proleptic Gregorian)” 달력의 정의와 일치하며, 모든 계산의 기본 달력입니다. 0과 음의 연도는 ISO 8601 표준에 규정된 대로 해석됩니다. 0년은 BC 1년, -1년은 BC 2년 등입니다.

class calendar.Calendar(firstweekday=0)

Creates a Calendar object. firstweekday is an integer specifying the first day of the week. MONDAY is 0 (the default), SUNDAY is 6.

Calendar 객체는 포매팅을 위해 달력 데이터를 준비하는 데 사용할 수 있는 몇 가지 메서드를 제공합니다. 이 클래스는 스스로 포매팅을 수행하지 않습니다. 이는 서브 클래스의 역할입니다.

Calendar 인스턴스에는 다음과 같은 메서드가 있습니다:

iterweekdays()

한 주 동안 사용될 요일 번호의 이터레이터를 반환합니다. 이터레이터의 첫 번째 값은 firstweekday 프로퍼티 값과 같습니다.

itermonthdates(year, month)

year 연도의 month 월 (1–12) 동안의 이터레이터를 반환합니다. 이 이터레이터는 해당 월의 모든 날(datetime.date 객체로)과 완전한 주를 얻기 위해 필요한 해당 월의 시작일 전이나 해당 월의 종료일 이후의 모든 날을 반환합니다.

itermonthdays(year, month)

itermonthdates()와 유사하게 year 연도의 month 월 동안의 이터레이터를 반환하지만, datetime.date 범위로 제한되지 않습니다. 반환된 날은 단순히 월 중 날 번호입니다. 지정된 월 바깥에 있는 날의 경우, 날 번호는 0입니다.

itermonthdays2(year, month)

itermonthdates()와 유사하게 year 연도의 month 월 동안의 이터레이터를 반환하지만, datetime.date 범위로 제한되지 않습니다. 반환된 날은 월 중 날 번호와 요일 번호로 구성된 튜플입니다.

itermonthdays3(year, month)

itermonthdates()와 유사하게 year 연도의 month 월 동안의 이터레이터를 반환하지만, datetime.date 범위로 제한되지 않습니다. 반환된 날은 연도, 월 및 월 중 날 번호로 구성된 튜플입니다.

Added in version 3.7.

itermonthdays4(year, month)

itermonthdates()와 유사하게 year 연도의 month 월 동안의 이터레이터를 반환하지만, datetime.date 범위로 제한되지 않습니다. 반환된 날은 연도, 월, 월 중 날 및 요일 번호로 구성된 튜플입니다.

Added in version 3.7.

monthdatescalendar(year, month)

year의 month 월에 있는 주의 리스트를 전체 주로 반환합니다. 주는 7개의 datetime.date 객체 리스트입니다.

monthdays2calendar(year, month)

year의 month 월에 있는 주의 리스트를 전체 주로 반환합니다. 주는 날 번호와 요일 번호 튜플 7개의 리스트입니다.

monthdayscalendar(year, month)

year의 month 월에 있는 주의 리스트를 전체 주로 반환합니다. 주는 날 번호 7개의 리스트입니다.

yeardatescalendar(year, width=3)

포매팅 준비된 지정된 연도의 데이터를 반환합니다. 반환 값은 월 행의 리스트입니다. 각 월 행에는 최대 width 월(기본값은 3)이 포함됩니다. 각 월은 4–6주를 포함하고, 각 주는 1–7일을 포함합니다. 날은 datetime.date 객체입니다.

yeardays2calendar(year, width=3)

포매팅 준비된 지정된 연도의 데이터를 반환합니다 (yeardatescalendar()와 유사합니다). 주 리스트의 항목은 날 번호와 요일 번호의 튜플입니다. 이달 밖의 날 번호는 0입니다.

yeardayscalendar(year, width=3)

포매팅 준비된 지정된 연도의 데이터를 반환합니다 (yeardatescalendar()와 유사합니다). 주 리스트의 항목은 날 번호입니다. 이달 밖의 날 번호는 0입니다.

class calendar.TextCalendar(firstweekday=0)

이 클래스는 평문 텍스트 달력을 생성하는 데 사용할 수 있습니다.

TextCalendar 인스턴스에는 다음과 같은 메서드가 있습니다:

formatmonth(theyear, themonth, w=0, l=0)

월의 달력을 여러 줄 문자열로 반환합니다. w가 제공되면, 가운데 정렬되는 날짜 열의 너비를 지정합니다. l이 제공되면, 각 주가 사용할 줄 수를 지정합니다. 생성자에 지정되거나 setfirstweekday() 메서드로 설정된 첫 번째 요일에 따라 다릅니다.

prmonth(theyear, themonth, w=0, l=0)

formatmonth()에서 반환한 월의 달력을 인쇄합니다.

formatyear(theyear, w=2, l=1, c=6, m=3)

전체 연도의 m-열 달력을 여러 줄 문자열로 반환합니다. 선택적 매개 변수 w, l 및 c는 각각 날짜 열 너비, 주당 줄 수 및 월 열 사이의 스페이스 수입니다. 생성자에 지정되거나 setfirstweekday() 메서드로 설정된 첫 번째 요일에 따라 다릅니다. 달력을 생성할 수 있는 가장 빠른 연도는 플랫폼에 따라 다릅니다.

pryear(theyear, w=2, l=1, c=6, m=3)

formatyear()에서 반환 연도의 달력을 인쇄합니다.

class calendar.HTMLCalendar(firstweekday=0)

이 클래스는 HTML 달력을 생성하는 데 사용할 수 있습니다.

HTMLCalendar 인스턴스에는 다음과 같은 메서드가 있습니다:

formatmonth(theyear, themonth, withyear=True)

월의 달력을 HTML 테이블로 반환합니다. withyear가 참이면 연도가 헤더에 포함되고, 그렇지 않으면 월 이름 만 사용됩니다.

formatyear(theyear, width=3)

연도의 달력을 HTML 테이블로 반환합니다. width(기본값은 3)는 행 당 개월 수를 지정합니다.

formatyearpage(theyear, width=3, css='calendar.css', encoding=None)

연도의 달력을 완전한 HTML 페이지로 반환합니다. width(기본값은 3)는 행 당 개월 수를 지정합니다. css는 사용할 캐스케이딩 스타일 시트의 이름입니다. 스타일 시트를 사용하지 않으면 None을 전달할 수 있습니다. encoding은 출력에 사용될 인코딩을 지정합니다 (기본값은 시스템 기본 인코딩입니다).

formatmonthname(theyear, themonth, withyear=True)

Return a month name as an HTML table row. If withyear is true the year will be included in the row, otherwise just the month name will be used.

HTMLCalendar에는 달력에서 사용하는 CSS 클래스를 사용자 정의하기 위해 재정의할 수 있는 다음과 같은 어트리뷰트가 있습니다:

cssclasses

각 요일에 사용되는 CSS 클래스 리스트. 기본 클래스 리스트는 다음과 같습니다:

cssclasses = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]

각 날에 더 많은 스타일을 추가할 수 있습니다:

cssclasses = ["mon text-bold", "tue", "wed", "thu", "fri", "sat", "sun red"]

이 리스트의 길이는 7개의 항목임에 유의하십시오.

cssclass_noday

지난달이나 다음 달에 등장하는 요일의 CSS 클래스.

Added in version 3.7.

cssclasses_weekday_head

헤더 행에 있는 요일 이름에 사용되는 CSS 클래스 리스트. 기본값은 cssclasses와 같습니다.

Added in version 3.7.

cssclass_month_head

월 헤드 CSS 클래스 (formatmonthname() 에서 사용됩니다). 기본값은 "month"입니다.

Added in version 3.7.

cssclass_month

월 전체 테이블의 CSS 클래스 (formatmonth()에서 사용됩니다). 기본값은 "month"입니다.

Added in version 3.7.

cssclass_year

연도 전체 표의 CSS 클래스 (formatyear()에서 사용됩니다). 기본값은 "year"입니다.

Added in version 3.7.

cssclass_year_head

연도 전체의 테이블 헤드의 CSS 클래스 (formatyear()에서 사용됩니다). 기본값은 "year"입니다.

Added in version 3.7.

위에서 설명한 클래스 어트리뷰트의 이름은 단수이지만 (예를 들어 cssclass_month cssclass_noday), 단일 CSS 클래스를 스페이스로 구분된 CSS 클래스 목록으로 바꿀 수 있습니다. 예를 들면 다음과 같습니다:

"text-bold text-red"

다음은 HTMLCalendar를 사용자 정의하는 방법에 대한 예입니다:

class CustomHTMLCal(calendar.HTMLCalendar):
    cssclasses = [style + " text-nowrap" for style in
                  calendar.HTMLCalendar.cssclasses]
    cssclass_month_head = "text-center month-head"
    cssclass_month = "text-center month"
    cssclass_year = "text-italic lead"

class calendar.LocaleTextCalendar(firstweekday=0, locale=None)

This subclass of TextCalendar can be passed a locale name in the constructor and will return month and weekday names in the specified locale.

class calendar.LocaleHTMLCalendar(firstweekday=0, locale=None)

This subclass of HTMLCalendar can be passed a locale name in the constructor and will return month and weekday names in the specified locale.

참고

The constructor, formatweekday() and formatmonthname() methods of these two classes temporarily change the LC_TIME locale to the given locale. Because the current locale is a process-wide setting, they are not thread-safe.

간단한 텍스트 달력을 위해 이 모듈은 다음 함수를 제공합니다.

calendar.setfirstweekday(weekday)

매주 시작일을 weekday(0은 월요일, 6은 일요일)로 설정합니다. 편의를 위해 MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY 및 SUNDAY 값이 제공됩니다. 예를 들어, 주의 첫 번째 날을 일요일로 설정하려면:

import calendar
calendar.setfirstweekday(calendar.SUNDAY)

calendar.firstweekday()

각 주를 시작하는 요일의 현재 설정을 반환합니다.

calendar.isleap(year)

year가 윤년이면 True를, 그렇지 않으면 False를 반환합니다.

calendar.leapdays(y1, y2)

y1에서 y2(우측 경계 제외) 범위에서 윤년의 수를 반환합니다, 여기서 y1과 y2는 연도입니다.

이 함수는 세기(century)의 변경을 포함하는 범위에서 작동합니다.

calendar.weekday(year, month, day)

year (1970–…), month (1–12), day (1–31)의 요일(0은 월요일)을 반환합니다.

calendar.weekheader(n)

약식 요일 이름이 포함된 헤더를 반환합니다. n은 한 주의 너비를 문자 수로 지정합니다.

calendar.monthrange(year, month)

지정된 year와 month에 대해 월의 첫 번째 날의 요일과 월의 날 수를 반환합니다.

calendar.monthcalendar(year, month)

한 달의 달력을 나타내는 행렬을 반환합니다. 각 행은 한 주를 나타냅니다; 월 바깥의 날은 0으로 표시됩니다. setfirstweekday()로 설정하지 않는 한 각 주는 월요일에 시작합니다.

calendar.prmonth(theyear, themonth, w=0, l=0)

month()가 반환하는 월의 달력을 인쇄합니다.

calendar.month(theyear, themonth, w=0, l=0)

Returns a month’s calendar in a multi-line string using the formatmonth() of the TextCalendar class.

calendar.prcal(year, w=0, l=0, c=6, m=3)

calendar()에서 반환 한 연도 전체 달력을 인쇄합니다.

calendar.calendar(year, w=2, l=1, c=6, m=3)

Returns a 3-column calendar for an entire year as a multi-line string using the formatyear() of the TextCalendar class.

calendar.timegm(tuple)

time 모듈의 gmtime() 함수가 반환하는 것과 같은 시간 튜플을 취하고, 1970년의 시작과 POSIX 인코딩을 가정하는 해당 유닉스 타임스탬프 값을 반환하는 관련이 없지만 편리한 함수. 실제로, time.gmtime()과 timegm()은 서로의 역 함수입니다.

calendar 모듈은 다음 데이터 어트리뷰트를 내보냅니다:

calendar.day_name

A sequence that represents the days of the week in the current locale, where Monday is day number 0.

>>> import calendar
>>> list(calendar.day_name)
['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']

calendar.day_abbr

A sequence that represents the abbreviated days of the week in the current locale, where Mon is day number 0.

>>> import calendar
>>> list(calendar.day_abbr)
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']

calendar.MONDAY

calendar.TUESDAY

calendar.WEDNESDAY

calendar.THURSDAY

calendar.FRIDAY

calendar.SATURDAY

calendar.SUNDAY

Aliases for the days of the week, where MONDAY is 0 and SUNDAY is 6.

Added in version 3.12.

class calendar.Day

Enumeration defining days of the week as integer constants. The members of this enumeration are exported to the module scope as MONDAY through SUNDAY.

Added in version 3.12.

calendar.month_name

A sequence that represents the months of the year in the current locale. This follows normal convention of January being month number 1, so it has a length of 13 and month_name[0] is the empty string.

>>> import calendar
>>> list(calendar.month_name)
['', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']

calendar.month_abbr

A sequence that represents the abbreviated months of the year in the current locale. This follows normal convention of January being month number 1, so it has a length of 13 and month_abbr[0] is the empty string.

>>> import calendar
>>> list(calendar.month_abbr)
['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

calendar.JANUARY

calendar.FEBRUARY

calendar.MARCH

calendar.APRIL

calendar.MAY

calendar.JUNE

calendar.JULY

calendar.AUGUST

calendar.SEPTEMBER

calendar.OCTOBER

calendar.NOVEMBER

calendar.DECEMBER

Aliases for the months of the year, where JANUARY is 1 and DECEMBER is 12.

Added in version 3.12.

class calendar.Month

Enumeration defining months of the year as integer constants. The members of this enumeration are exported to the module scope as JANUARY through DECEMBER.

Added in version 3.12.

The calendar module defines the following exceptions:

exception calendar.IllegalMonthError(month)

A subclass of ValueError, raised when the given month number is outside of the range 1-12 (inclusive).

month

The invalid month number.

exception calendar.IllegalWeekdayError(weekday)

A subclass of ValueError, raised when the given weekday number is outside of the range 0-6 (inclusive).

weekday

The invalid weekday number.

더 보기

모듈 datetime

time 모듈과 유사한 기능을 가진 날짜와 시간에 대한 객체 지향 인터페이스.

모듈 time

저수준 시간 관련 함수.

Command-Line Usage

Added in version 2.5.

The calendar module can be executed as a script from the command line to interactively print a calendar.

python -m calendar [-h] [-L LOCALE] [-e ENCODING] [-t {text,html}]
                   [-w WIDTH] [-l LINES] [-s SPACING] [-m MONTHS] [-c CSS]
                   [-f FIRST_WEEKDAY] [year] [month]

For example, to print a calendar for the year 2000:

$ python -m calendar 2000
                                  2000

      January                   February                   March
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                1  2          1  2  3  4  5  6             1  2  3  4  5
 3  4  5  6  7  8  9       7  8  9 10 11 12 13       6  7  8  9 10 11 12
10 11 12 13 14 15 16      14 15 16 17 18 19 20      13 14 15 16 17 18 19
17 18 19 20 21 22 23      21 22 23 24 25 26 27      20 21 22 23 24 25 26
24 25 26 27 28 29 30      28 29                     27 28 29 30 31
31

       April                      May                       June
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                1  2       1  2  3  4  5  6  7                1  2  3  4
 3  4  5  6  7  8  9       8  9 10 11 12 13 14       5  6  7  8  9 10 11
10 11 12 13 14 15 16      15 16 17 18 19 20 21      12 13 14 15 16 17 18
17 18 19 20 21 22 23      22 23 24 25 26 27 28      19 20 21 22 23 24 25
24 25 26 27 28 29 30      29 30 31                  26 27 28 29 30

        July                     August                  September
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                1  2          1  2  3  4  5  6                   1  2  3
 3  4  5  6  7  8  9       7  8  9 10 11 12 13       4  5  6  7  8  9 10
10 11 12 13 14 15 16      14 15 16 17 18 19 20      11 12 13 14 15 16 17
17 18 19 20 21 22 23      21 22 23 24 25 26 27      18 19 20 21 22 23 24
24 25 26 27 28 29 30      28 29 30 31               25 26 27 28 29 30
31

      October                   November                  December
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                   1             1  2  3  4  5                   1  2  3
 2  3  4  5  6  7  8       6  7  8  9 10 11 12       4  5  6  7  8  9 10
 9 10 11 12 13 14 15      13 14 15 16 17 18 19      11 12 13 14 15 16 17
16 17 18 19 20 21 22      20 21 22 23 24 25 26      18 19 20 21 22 23 24
23 24 25 26 27 28 29      27 28 29 30               25 26 27 28 29 30 31
30 31

The following options are accepted:

--help, -h

Show the help message and exit.

--locale LOCALE, -L LOCALE

The locale to use for month and weekday names. Defaults to English.

--encoding ENCODING, -e ENCODING

The encoding to use for output. --encoding is required if --locale is set.

--type {text,html}, -t {text,html}

Print the calendar to the terminal as text, or as an HTML document.

--first-weekday FIRST_WEEKDAY, -f FIRST_WEEKDAY

The weekday to start each week. Must be a number between 0 (Monday) and 6 (Sunday). Defaults to 0.

Added in version 3.13.

year

The year to print the calendar for. Defaults to the current year.

month

The month of the specified year to print the calendar for. Must be a number between 1 and 12, and may only be used in text mode. Defaults to printing a calendar for the full year.

Text-mode options:

--width WIDTH, -w WIDTH

The width of the date column in terminal columns. The date is printed centred in the column. Any value lower than 2 is ignored. Defaults to 2.

--lines LINES, -l LINES

The number of lines for each week in terminal rows. The date is printed top-aligned. Any value lower than 1 is ignored. Defaults to 1.

--spacing SPACING, -s SPACING

The space between months in columns. Any value lower than 2 is ignored. Defaults to 6.

--months MONTHS, -m MONTHS

The number of months printed per row. Defaults to 3.

HTML-mode options:

--css CSS, -c CSS

The path of a CSS stylesheet to use for the calendar. This must either be relative to the generated HTML, or an absolute HTTP or file:/// URL.

collections — Container datatypes

소스 코드: Lib/collections/__init__.py [https://github.com/python/cpython/tree/main/Lib/collections/__init__.py]

이 모듈은 파이썬의 범용 내장 컨테이너 dict, list, set 및 tuple에 대한 대안을 제공하는 특수 컨테이너 데이터형을 구현합니다.

namedtuple()

이름 붙은 필드를 갖는 튜플 서브 클래스를 만들기 위한 팩토리 함수

deque

양쪽 끝에서 빠르게 추가와 삭제를 할 수 있는 리스트류 컨테이너

ChainMap

여러 매핑의 단일 뷰를 만드는 딕셔너리류 클래스

Counter

dict subclass for counting hashable objects

OrderedDict

항목이 추가된 순서를 기억하는 딕셔너리 서브 클래스

defaultdict

누락된 값을 제공하기 위해 팩토리 함수를 호출하는 딕셔너리 서브 클래스

UserDict

더 쉬운 딕셔너리 서브 클래싱을 위해 딕셔너리 객체를 감싸는 래퍼

UserList

더 쉬운 리스트 서브 클래싱을 위해 리스트 객체를 감싸는 래퍼

UserString

더 쉬운 문자열 서브 클래싱을 위해 문자열 객체를 감싸는 래퍼

ChainMap 객체

Added in version 3.3.

ChainMap 클래스는 여러 매핑을 빠르게 연결하여 단일 단위로 취급 할 수 있도록 합니다. 종종 새로운 딕셔너리를 만들고 여러 update() 호출을 실행하는 것보다 훨씬 빠릅니다.

이 클래스는 중첩된 스코프를 시뮬레이션하는 데 사용할 수 있으며 템플릿에 유용합니다.

class collections.ChainMap(*maps)

ChainMap은 여러 딕셔너리나 다른 매핑을 함께 묶어 갱신 가능한 단일 뷰를 만듭니다. maps가 지정되지 않으면, 새 체인에 항상 하나 이상의 매핑이 있도록, 빈 딕셔너리 하나가 제공됩니다.

하부 매핑은 리스트에 저장됩니다. 이 리스트는 공개이며 maps 어트리뷰트를 사용하여 액세스하거나 갱신할 수 있습니다. 다른 상태는 없습니다.

조회는 키를 찾을 때까지 하부 매핑을 검색합니다. 반면에, 쓰기, 갱신 및 삭제는 첫 번째 매핑에만 작동합니다.

ChainMap은 하부 매핑을 참조로 통합합니다. 따라서 하부 매핑 중 하나가 갱신되면 해당 변경 사항이 ChainMap에 반영됩니다.

일반적인 딕셔너리 메서드가 모두 지원됩니다. 또한, maps 어트리뷰트, 새 서브 컨텍스트를 만드는 메서드 및 첫 번째 매핑을 제외한 모든 것에 액세스하는 프로퍼티가 있습니다:

maps

사용자 갱신 가능한 매핑 리스트. 리스트는 먼저 검색되는 것에서 나중에 검색되는 순서를 따릅니다. 저장된 유일한 상태이며 검색할 매핑을 변경하도록 수정할 수 있습니다. 리스트는 항상 하나 이상의 매핑이 포함되어야 합니다.

new_child(m=None, **kwargs)

Returns a new ChainMap containing a new map followed by all of the maps in the current instance. If m is specified, it becomes the new map at the front of the list of mappings; if not specified, an empty dict is used, so that a call to d.new_child() is equivalent to: ChainMap({}, *d.maps). If any keyword arguments are specified, they update passed map or new empty dict. This method is used for creating subcontexts that can be updated without altering values in any of the parent mappings.

버전 3.4에서 변경: 선택적 m 매개 변수가 추가되었습니다.

버전 3.10에서 변경: Keyword arguments support was added.

parents

첫 번째 맵을 제외하고 현재 인스턴스의 모든 맵을 포함하는 새 ChainMap을 반환하는 프로퍼티. 검색에서 첫 번째 맵을 건너뛰려고 할 때 유용합니다. 사용 사례는 중첩된 스코프에서 사용되는 nonlocal 키워드와 유사합니다. 사용 사례는 내장 super() 함수와도 유사합니다. d.parents에 대한 참조는 ChainMap(*d.maps[1:])과 동등합니다.

Note, the iteration order of a ChainMap is determined by scanning the mappings last to first:

>>> baseline = {'music': 'bach', 'art': 'rembrandt'}
>>> adjustments = {'art': 'van gogh', 'opera': 'carmen'}
>>> list(ChainMap(adjustments, baseline))
['music', 'art', 'opera']

이것은 마지막 매핑에서 시작하는 일련의 dict.update() 호출과 같은 순서를 제공합니다:

>>> combined = baseline.copy()
>>> combined.update(adjustments)
>>> list(combined)
['music', 'art', 'opera']

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]에 지정된, |와 |= 연산자에 대한 지원이 추가되었습니다.

더 보기

Enthought CodeTools 패키지 [https://github.com/enthought/codetools]의 MultiContext 클래스 [https://github.com/enthought/codetools/blob/4.0.0/codetools/contexts/multi_context.py]에는 체인의 모든 매핑으로의 쓰기를 지원하는 옵션이 있습니다.

템플릿을 위한 Django의 Context 클래스 [https://github.com/django/django/blob/main/django/template/context.py]는 읽기 전용 매핑 체인입니다. 또한 new_child() 메서드와 parents 프로퍼티와 유사하게 컨텍스트를 푸시(push)하고 팝(pop) 하는 기능이 있습니다.

The Nested Contexts recipe [https://code.activestate.com/recipes/577434-nested-contexts-a-chain-of-mapping-objects/] has options to control whether writes and other mutations apply only to the first mapping or to any mapping in the chain.

매우 단순화된 체인 맵의 읽기 전용 버전 [https://code.activestate.com/recipes/305268/]

ChainMap 예제와 조리법

이 절에서는 체인 맵으로 작업하는 다양한 접근 방식을 보여줍니다.

파이썬의 내부 조회 체인을 시뮬레이션하는 예:

import builtins
pylookup = ChainMap(locals(), globals(), vars(builtins))

사용자 지정 명령 줄 인자가 환경 변수보다 우선하고, 환경 변수는 기본값보다 우선하도록 하는 예:

import os, argparse

defaults = {'color': 'red', 'user': 'guest'}

parser = argparse.ArgumentParser()
parser.add_argument('-u', '--user')
parser.add_argument('-c', '--color')
namespace = parser.parse_args()
command_line_args = {k: v for k, v in vars(namespace).items() if v is not None}

combined = ChainMap(command_line_args, os.environ, defaults)
print(combined['color'])
print(combined['user'])

중첩된 컨텍스트를 시뮬레이션하기 위해 ChainMap 클래스를 사용하는 예제 패턴:

c = ChainMap()        # Create root context
d = c.new_child()     # Create nested child context
e = c.new_child()     # Child of c, independent from d
e.maps[0]             # Current context dictionary -- like Python's locals()
e.maps[-1]            # Root context -- like Python's globals()
e.parents             # Enclosing context chain -- like Python's nonlocals

d['x'] = 1            # Set value in current context
d['x']                # Get first key in the chain of contexts
del d['x']            # Delete from current context
list(d)               # All nested values
k in d                # Check all nested values
len(d)                # Number of nested values
d.items()             # All nested items
dict(d)               # Flatten into a regular dictionary

ChainMap 클래스는 체인의 첫 번째 매핑만 갱신(쓰기와 삭제)하지만, 조회는 전체 체인을 검색합니다. 그러나, 깊은 쓰기와 삭제가 필요하면, 체인의 더 깊은 곳에서 발견된 키를 갱신하는 서브 클래스를 쉽게 만들 수 있습니다:

class DeepChainMap(ChainMap):
    'Variant of ChainMap that allows direct updates to inner scopes'

    def __setitem__(self, key, value):
        for mapping in self.maps:
            if key in mapping:
                mapping[key] = value
                return
        self.maps[0][key] = value

    def __delitem__(self, key):
        for mapping in self.maps:
            if key in mapping:
                del mapping[key]
                return
        raise KeyError(key)

>>> d = DeepChainMap({'zebra': 'black'}, {'elephant': 'blue'}, {'lion': 'yellow'})
>>> d['lion'] = 'orange'         # update an existing key two levels down
>>> d['snake'] = 'red'           # new keys get added to the topmost dict
>>> del d['elephant']            # remove an existing key one level down
>>> d                            # display result
DeepChainMap({'zebra': 'black', 'snake': 'red'}, {}, {'lion': 'orange'})

Counter 객체

편리하고 빠르게 개수를 세도록 지원하는 계수기 도구가 제공됩니다. 예를 들면:

>>> # Tally occurrences of words in a list
>>> cnt = Counter()
>>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:
...     cnt[word] += 1
...
>>> cnt
Counter({'blue': 3, 'red': 2, 'green': 1})

>>> # Find the ten most common words in Hamlet
>>> import re
>>> words = re.findall(r'\w+', open('hamlet.txt').read().lower())
>>> Counter(words).most_common(10)
[('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),
 ('you', 554),  ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)]

class collections.Counter([iterable-or-mapping])

A Counter is a dict subclass for counting hashable objects. It is a collection where elements are stored as dictionary keys and their counts are stored as dictionary values. Counts are allowed to be any integer value including zero or negative counts. The Counter class is similar to bags or multisets in other languages.

요소는 이터러블로부터 계산되거나 다른 매핑(또는 계수기)에서 초기화됩니다:

>>> c = Counter()                           # a new, empty counter
>>> c = Counter('gallahad')                 # a new counter from an iterable
>>> c = Counter({'red': 4, 'blue': 2})      # a new counter from a mapping
>>> c = Counter(cats=4, dogs=8)             # a new counter from keyword args

계수기 객체는 누락된 항목에 대해 KeyError를 발생시키는 대신 0을 반환한다는 점을 제외하고 딕셔너리 인터페이스를 갖습니다:

>>> c = Counter(['eggs', 'ham'])
>>> c['bacon']                              # count of a missing element is zero
0

개수를 0으로 설정해도 계수기에서 요소가 제거되지 않습니다. 완전히 제거하려면 del을 사용하십시오:

>>> c['sausage'] = 0                        # counter entry with a zero count
>>> del c['sausage']                        # del actually removes the entry

Added in version 3.1.

버전 3.7에서 변경: As a dict subclass, Counter inherited the capability to remember insertion order. Math operations on Counter objects also preserve order. Results are ordered according to when an element is first encountered in the left operand and then by the order encountered in the right operand.

Counter objects support additional methods beyond those available for all dictionaries:

elements()

개수만큼 반복되는 요소에 대한 이터레이터를 반환합니다. 요소는 처음 발견되는 순서대로 반환됩니다. 요소의 개수가 1보다 작으면 elements()는 이를 무시합니다.

>>> c = Counter(a=4, b=2, c=0, d=-2)
>>> sorted(c.elements())
['a', 'a', 'a', 'a', 'b', 'b']

most_common([n])

n 개의 가장 흔한 요소와 그 개수를 가장 흔한 것부터 가장 적은 것 순으로 나열한 리스트를 반환합니다. n이 생략되거나 None이면, most_common()은 계수기의 모든 요소를 반환합니다. 개수가 같은 요소는 처음 발견된 순서를 유지합니다:

>>> Counter('abracadabra').most_common(3)
[('a', 5), ('b', 2), ('r', 2)]

subtract([iterable-or-mapping])

이터러블이나 다른 매핑 (또는 계수기)으로부터 온 요소들을 뺍니다. dict.update()와 비슷하지만 교체하는 대신 개수를 뺍니다. 입력과 출력 모두 0이나 음수일 수 있습니다.

>>> c = Counter(a=4, b=2, c=0, d=-2)
>>> d = Counter(a=1, b=2, c=3, d=4)
>>> c.subtract(d)
>>> c
Counter({'a': 3, 'b': 0, 'c': -3, 'd': -6})

Added in version 3.2.

total()

Compute the sum of the counts.

>>> c = Counter(a=10, b=5, c=0)
>>> c.total()
15

Added in version 3.10.

일반적인 딕셔너리 메서드를 Counter 객체에 사용할 수 있습니다만, 두 메서드는 계수기에서 다르게 동작합니다.

fromkeys(iterable)

이 클래스 메서드는 Counter 객체에 구현되지 않았습니다.

update([iterable-or-mapping])

요소는 이터러블에서 세거나 다른 매핑(또는 계수기)에서 더해집니다. dict.update()와 비슷하지만, 교체하는 대신 더합니다. 또한, 이터러블은 (key, value) 쌍의 시퀀스가 아닌, 요소의 시퀀스일 것으로 기대합니다.

Counters support rich comparison operators for equality, subset, and superset relationships: ==, !=, <, <=, >, >=. All of those tests treat missing elements as having zero counts so that Counter(a=1) == Counter(a=1, b=0) returns true.

버전 3.10에서 변경: Rich comparison operations were added.

버전 3.10에서 변경: In equality tests, missing elements are treated as having zero counts. Formerly, Counter(a=3) and Counter(a=3, b=0) were considered distinct.

Counter 객체로 작업하는 일반적인 패턴:

c.total()                       # total of all counts
c.clear()                       # reset all counts
list(c)                         # list unique elements
set(c)                          # convert to a set
dict(c)                         # convert to a regular dictionary
c.items()                       # access the (elem, cnt) pairs
Counter(dict(list_of_pairs))    # convert from a list of (elem, cnt) pairs
c.most_common()[:-n-1:-1]       # n least common elements
+c                              # remove zero and negative counts

Several mathematical operations are provided for combining Counter objects to produce multisets (counters that have counts greater than zero). Addition and subtraction combine counters by adding or subtracting the counts of corresponding elements. Intersection and union return the minimum and maximum of corresponding counts. Equality and inclusion compare corresponding counts. Each operation can accept inputs with signed counts, but the output will exclude results with counts of zero or less.

>>> c = Counter(a=3, b=1)
>>> d = Counter(a=1, b=2)
>>> c + d                       # add two counters together:  c[x] + d[x]
Counter({'a': 4, 'b': 3})
>>> c - d                       # subtract (keeping only positive counts)
Counter({'a': 2})
>>> c & d                       # intersection:  min(c[x], d[x])
Counter({'a': 1, 'b': 1})
>>> c | d                       # union:  max(c[x], d[x])
Counter({'a': 3, 'b': 2})
>>> c == d                      # equality:  c[x] == d[x]
False
>>> c <= d                      # inclusion:  c[x] <= d[x]
False

단항 덧셈과 뺄셈은 빈 계수기를 더하거나 빈 계수기를 빼는 것의 줄임 표현입니다.

>>> c = Counter(a=2, b=-4)
>>> +c
Counter({'a': 2})
>>> -c
Counter({'b': 4})

Added in version 3.3: 단항 플러스, 단항 마이너스 및 제자리 멀티 셋 연산에 대한 지원이 추가되었습니다.

참고

계수기는 주로 양의 정수로 작동하여 횟수를 나타내도록 설계되었습니다; 그러나, 다른 형이나 음수 값이 필요한 사용 사례를 불필요하게 배제하지 않도록 주의를 기울였습니다. 이러한 사용 사례에 도움이 되도록, 이 절은 최소 범위와 형 제약 사항을 설명합니다.

Counter 클래스 자체는 키와 값에 제한이 없는 딕셔너리 서브 클래스입니다. 값은 개수를 나타내는 숫자로 의도되었지만, 값 필드에 어떤 것이든 저장할 수 있습니다.

most_common() 메서드는 값에 대해 순서만을 요구합니다.

c[key] += 1과 같은 제자리 연산의 경우, 값 형은 덧셈과 뺄셈만 지원하면 됩니다. 따라서 분수(fractions), 부동 소수점(floats) 및 십진수(decimals)가 작동하고 음수 값이 지원됩니다. update()와 subtract()에 대해서도 마찬가지인데, 입력과 출력 모두 음수와 0을 허용합니다.

멀티 셋(multiset) 메서드는 양의 값에 대한 사용 사례를 위해서만 설계되었습니다. 입력은 음수이거나 0일 수 있지만, 양수 값을 갖는 출력만 만들어집니다. 형 제한은 없지만, 값 형은 더하기, 빼기 및 비교를 지원해야 합니다.

elements() 메서드는 정수 개수를 요구합니다. 0과 음수 개수는 무시합니다.

더 보기

스몰토크(Smalltalk)의 Bag 클래스 [https://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html].

Multisets [https://en.wikipedia.org/wiki/Multiset]에 대한 위키피디아 항목.

예제가 포함된 C++ multisets [http://www.java2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm] 자습서.

멀티 셋에 대한 수학 연산과 그 사용 사례에 대해서는, Knuth, Donald. The Art of Computer Programming Volume II, Section 4.6.3, Exercise 19를 참조하십시오.

주어진 요소 집합에 대해 주어진 크기의 모든 서로 다른 멀티 셋을 열거하려면, itertools.combinations_with_replacement()를 참조하십시오:

map(Counter, combinations_with_replacement('ABC', 2)) # --> AA AB AC BB BC CC

deque 객체

class collections.deque([iterable[, maxlen]])

iterable의 데이터로 왼쪽에서 오른쪽으로 (append()를 사용해서) 초기화된 새 데크(deque) 객체를 반환합니다. iterable을 지정하지 않으면, 새 데크는 비어 있습니다.

Deques are a generalization of stacks and queues (the name is pronounced “deck” and is short for “double-ended queue”). Deques support thread-safe, memory efficient appends and pops from either side of the deque with approximately the same O(1) performance in either direction.

Though list objects support similar operations, they are optimized for fast fixed-length operations and incur O(n) memory movement costs for pop(0) and insert(0, v) operations which change both the size and position of the underlying data representation.

maxlen이 지정되지 않거나 None이면, 데크는 임의의 길이로 커질 수 있습니다. 그렇지 않으면, 데크는 지정된 최대 길이로 제한됩니다. 일단 제한된 길이의 데크가 가득 차면, 새 항목이 추가될 때, 해당하는 수의 항목이 반대쪽 끝에서 삭제됩니다. 제한된 길이의 데크는 유닉스의 tail 필터와 유사한 기능을 제공합니다. 또한 가장 최근 활동만 관심이 있는 트랜잭션과 기타 데이터 풀을 추적하는 데 유용합니다.

deque 객체는 다음 메서드를 지원합니다:

append(x)

데크의 오른쪽에 x를 추가합니다.

appendleft(x)

데크의 왼쪽에 x를 추가합니다.

clear()

데크에서 모든 요소를 제거하고 길이가 0인 상태로 만듭니다.

copy()

데크의 얕은 복사본을 만듭니다.

Added in version 3.5.

count(x)

x 와 같은 데크 요소의 수를 셉니다.

Added in version 3.2.

extend(iterable)

iterable 인자에서 온 요소를 추가하여 데크의 오른쪽을 확장합니다.

extendleft(iterable)

iterable에서 온 요소를 추가하여 데크의 왼쪽을 확장합니다. 일련의 왼쪽 추가는 iterable 인자에 있는 요소의 순서를 뒤집는 결과를 줍니다.

index(x[, start[, stop]])

데크에 있는 x의 위치를 반환합니다 (인덱스 start 또는 그 이후, 그리고 인덱스 stop 이전). 첫 번째 일치를 반환하거나 찾을 수 없으면 ValueError를 발생시킵니다.

Added in version 3.5.

insert(i, x)

x를 데크의 i 위치에 삽입합니다.

삽입으로 인해 제한된 길이의 데크가 maxlen 이상으로 커지면, IndexError가 발생합니다.

Added in version 3.5.

pop()

데크의 오른쪽에서 요소를 제거하고 반환합니다. 요소가 없으면, IndexError를 발생시킵니다.

popleft()

데크의 왼쪽에서 요소를 제거하고 반환합니다. 요소가 없으면, IndexError를 발생시킵니다.

remove(value)

value의 첫 번째 항목을 제거합니다. 찾을 수 없으면, ValueError를 발생시킵니다.

reverse()

데크의 요소들을 제자리에서 순서를 뒤집고 None을 반환합니다.

Added in version 3.2.

rotate(n=1)

데크를 n 단계 오른쪽으로 회전합니다. n이 음수이면, 왼쪽으로 회전합니다.

데크가 비어 있지 않으면, 오른쪽으로 한 단계 회전하는 것은 d.appendleft(d.pop())과 동등하고, 왼쪽으로 한 단계 회전하는 것은 d.append(d.popleft())와 동등합니다.

데크 객체는 하나의 읽기 전용 어트리뷰트도 제공합니다:

maxlen

데크의 최대 크기 또는 제한이 없으면 None.

Added in version 3.1.

In addition to the above, deques support iteration, pickling, len(d), reversed(d), copy.copy(d), copy.deepcopy(d), membership testing with the in operator, and subscript references such as d[0] to access the first element. Indexed access is O(1) at both ends but slows to O(n) in the middle. For fast random access, use lists instead.

버전 3.5부터, 데크는 __add__(), __mul__() 및 __imul__()을 지원합니다.

예:

>>> from collections import deque
>>> d = deque('ghi')                 # make a new deque with three items
>>> for elem in d:                   # iterate over the deque's elements
...     print(elem.upper())
G
H
I

>>> d.append('j')                    # add a new entry to the right side
>>> d.appendleft('f')                # add a new entry to the left side
>>> d                                # show the representation of the deque
deque(['f', 'g', 'h', 'i', 'j'])

>>> d.pop()                          # return and remove the rightmost item
'j'
>>> d.popleft()                      # return and remove the leftmost item
'f'
>>> list(d)                          # list the contents of the deque
['g', 'h', 'i']
>>> d[0]                             # peek at leftmost item
'g'
>>> d[-1]                            # peek at rightmost item
'i'

>>> list(reversed(d))                # list the contents of a deque in reverse
['i', 'h', 'g']
>>> 'h' in d                         # search the deque
True
>>> d.extend('jkl')                  # add multiple elements at once
>>> d
deque(['g', 'h', 'i', 'j', 'k', 'l'])
>>> d.rotate(1)                      # right rotation
>>> d
deque(['l', 'g', 'h', 'i', 'j', 'k'])
>>> d.rotate(-1)                     # left rotation
>>> d
deque(['g', 'h', 'i', 'j', 'k', 'l'])

>>> deque(reversed(d))               # make a new deque in reverse order
deque(['l', 'k', 'j', 'i', 'h', 'g'])
>>> d.clear()                        # empty the deque
>>> d.pop()                          # cannot pop from an empty deque
Traceback (most recent call last):
    File "<pyshell#6>", line 1, in -toplevel-
        d.pop()
IndexError: pop from an empty deque

>>> d.extendleft('abc')              # extendleft() reverses the input order
>>> d
deque(['c', 'b', 'a'])

deque 조리법

이 절은 데크로 작업하는 다양한 접근 방식을 보여줍니다.

제한된 길이의 데크는 유닉스의 tail 필터와 유사한 기능을 제공합니다:

def tail(filename, n=10):
    'Return the last n lines of a file'
    with open(filename) as f:
        return deque(f, n)

데크를 사용하는 또 다른 접근법은 오른쪽에 추가하고 왼쪽에서 팝 하여 최근에 추가된 요소의 시퀀스를 유지하는 것입니다:

def moving_average(iterable, n=3):
    # moving_average([40, 30, 50, 46, 39, 44]) --> 40.0 42.0 45.0 43.0
    # https://en.wikipedia.org/wiki/Moving_average
    it = iter(iterable)
    d = deque(itertools.islice(it, n-1))
    d.appendleft(0)
    s = sum(d)
    for elem in it:
        s += elem - d.popleft()
        d.append(elem)
        yield s / n

라운드 로빈 스케줄러(round-robin scheduler) [https://en.wikipedia.org/wiki/Round-robin_scheduling]는 deque에 저장된 입력 이터레이터로 구현할 수 있습니다. 위치 0에 있는 활성 이터레이터에서 값이 산출됩니다. 그 이터레이터가 소진되면, popleft()로 제거할 수 있습니다; 그렇지 않으면, rotate() 메서드로 끝으로 보내 순환할 수 있습니다:

def roundrobin(*iterables):
    "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
    iterators = deque(map(iter, iterables))
    while iterators:
        try:
            while True:
                yield next(iterators[0])
                iterators.rotate(-1)
        except StopIteration:
            # Remove an exhausted iterator.
            iterators.popleft()

rotate() 메서드는 deque 슬라이싱과 삭제를 구현하는 방법을 제공합니다. 예를 들어, del d[n]의 순수 파이썬 구현은 팝 될 요소의 위치를 잡기 위해 rotate() 메서드에 의존합니다:

def delete_nth(d, n):
    d.rotate(-n)
    d.popleft()
    d.rotate(n)

deque 슬라이싱을 구현하려면, 대상 요소를 데크의 왼쪽으로 가져오기 위해 rotate()를 적용하는 유사한 접근법을 사용하십시오. popleft()로 이전 항목을 제거하고, extend()로 새 항목을 추가한 다음, 회전을 되돌립니다. 이 접근 방식에 약간의 변형을 가하면, dup, drop, swap, over, pick, rot 및 roll과 같은 Forth 스타일 스택 조작을 쉽게 구현할 수 있습니다.

defaultdict 객체

class collections.defaultdict(default_factory=None, /[, ...])

Return a new dictionary-like object. defaultdict is a subclass of the built-in dict class. It overrides one method and adds one writable instance variable. The remaining functionality is the same as for the dict class and is not documented here.

첫 번째 인자는 default_factory 어트리뷰트의 초깃값을 제공합니다; 기본값은 None입니다. 나머지 모든 인자는 키워드 인자를 포함하여 dict 생성자에 전달될 때와 마찬가지로 취급됩니다.

defaultdict 객체는 표준 dict 연산 외에도 다음 메서드를 지원합니다:

__missing__(key)

default_factory 어트리뷰트가 None이면, key를 인자로 사용하는 KeyError 예외가 발생합니다.

default_factory가 None이 아니면, 주어진 key에 대한 기본값을 제공하기 위해 인자 없이 호출되며, 반환 값은 key로 딕셔너리에 삽입되고 반환됩니다.

default_factory를 호출할 때 예외가 발생하면 이 예외는 변경되지 않고 전파됩니다.

This method is called by the __getitem__() method of the dict class when the requested key is not found; whatever it returns or raises is then returned or raised by __getitem__().

Note that __missing__() is not called for any operations besides __getitem__(). This means that get() will, like normal dictionaries, return None as a default rather than using default_factory.

defaultdict 객체는 다음 인스턴스 변수를 지원합니다:

default_factory

이 어트리뷰트는 __missing__() 메서드에서 사용됩니다; 생성자의 첫 번째 인자가 있으면 그것으로, 없으면 None으로 초기화됩니다.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]에 지정된, 병합(|)과 업데이트(|=) 연산자가 추가되었습니다.

defaultdict 예

list를 default_factory로 사용하면, 키-값 쌍의 시퀀스를 리스트의 딕셔너리로 쉽게 그룹화 할 수 있습니다:

>>> s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
>>> d = defaultdict(list)
>>> for k, v in s:
...     d[k].append(v)
...
>>> sorted(d.items())
[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

각 키가 처음 발견될 때, 아직 매핑에 있지 않게 됩니다; 그래서 default_factory 함수를 사용하여 항목이 자동으로 만들어지는데, 빈 list를 반환합니다. 그런 다음 list.append() 연산이 값을 새 리스트에 추가합니다. 키를 다시 만나면, 조회가 정상적으로 진행되고 (해당 키의 리스트를 반환합니다), list.append() 연산은 다른 값을 리스트에 추가합니다. 이 기법은 dict.setdefault()를 사용하는 동등한 기법보다 간단하고 빠릅니다:

>>> d = {}
>>> for k, v in s:
...     d.setdefault(k, []).append(v)
...
>>> sorted(d.items())
[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

default_factory를 int로 설정하면 defaultdict를 세는(counting) 데 유용하게 사용할 수 있습니다 (다른 언어의 백(bag)이나 멀티 셋(multiset)처럼):

>>> s = 'mississippi'
>>> d = defaultdict(int)
>>> for k in s:
...     d[k] += 1
...
>>> sorted(d.items())
[('i', 4), ('m', 1), ('p', 2), ('s', 4)]

글자가 처음 발견될 때, 매핑에서 누락되었으므로, default_factory 함수는 int()를 호출하여 기본 계수 0을 제공합니다. 증분 연산은 각 문자의 개수를 쌓아나갑니다.

항상 0을 반환하는 함수 int()는 상수 함수의 특별한 경우일 뿐입니다. 상수 함수를 만드는 더 빠르고 유연한 방법은 (단지 0이 아니라) 임의의 상숫값을 제공 할 수 있는 람다 함수를 사용하는 것입니다:

>>> def constant_factory(value):
...     return lambda: value
...
>>> d = defaultdict(constant_factory('<missing>'))
>>> d.update(name='John', action='ran')
>>> '%(name)s %(action)s to %(object)s' % d
'John ran to <missing>'

default_factory를 set으로 설정하면, defaultdict를 집합의 딕셔너리를 만드는 데 유용하게 만듭니다:

>>> s = [('red', 1), ('blue', 2), ('red', 3), ('blue', 4), ('red', 1), ('blue', 4)]
>>> d = defaultdict(set)
>>> for k, v in s:
...     d[k].add(v)
...
>>> sorted(d.items())
[('blue', {2, 4}), ('red', {1, 3})]

이름있는 필드를 가진 튜플을 위한 namedtuple() 팩토리 함수

네임드 튜플은 튜플의 각 위치에 의미를 부여하고 더 읽기 쉽고 스스로 설명하는 코드를 만들도록 합니다. 일반 튜플이 사용되는 곳이라면 어디에서나 사용할 수 있으며, 위치 인덱스 대신 이름으로 필드에 액세스하는 기능을 추가합니다.

collections.namedtuple(typename, field_names, *, rename=False, defaults=None, module=None)

typename이라는 이름의 새 튜플 서브 클래스를 반환합니다. 새로운 서브 클래스는 인덱싱되고 이터러블일 뿐만 아니라 어트리뷰트 조회로 액세스 할 수 있는 필드를 갖는 튜플류 객체를 만드는 데 사용됩니다. 서브 클래스의 인스턴스에는 유용한 독스트링(typename과 field_names를 포함합니다)과 튜플 내용을 name=value 형식으로 나열하는 유용한 __repr__() 메서드가 있습니다.

field_names는 ['x', 'y']와 같은 문자열의 시퀀스입니다. 또는, field_names는 각 필드명이 공백 및/또는 쉼표로 구분된 단일 문자열일 수 있습니다, 예를 들어 'x y'나 'x, y'.

밑줄로 시작하는 이름을 제외한 모든 유효한 파이썬 식별자를 필드명에 사용할 수 있습니다. 유효한 식별자는 글자, 숫자 및 밑줄로 구성되지만, 숫자나 밑줄로 시작하지 않으며 class, for, return, global, pass 또는 raise와 같은 keyword일 수 없습니다.

rename이 참이면, 유효하지 않은 필드명은 위치 이름으로 자동 대체됩니다. 예를 들어, ['abc', 'def', 'ghi', 'abc']는 ['abc', '_1', 'ghi', '_3']으로 변환되어 키워드 def와 중복된 필드명 abc를 제거합니다.

defaults는 None이나 기본값의 이터러블 일 수 있습니다. 기본값이 있는 필드는 기본값이 없는 필드 뒤에 와야 하므로, defaults는 가장 오른쪽의 매개 변수에 적용됩니다. 예를 들어, field_names가 ['x', 'y', 'z']이고 defaults가 (1, 2)이면 x는 필수 인자이고, y의 기본값은 1, z의 기본값은 2입니다.

If module is defined, the __module__ attribute of the named tuple is set to that value.

네임드 튜플 인스턴스에는 인스턴스 별 딕셔너리가 없어서, 가볍고 일반 튜플보다 더 많은 메모리가 필요하지 않습니다.

피클링을 지원하려면, 네임드 튜플 클래스를 typename과 일치하는 변수에 대입해야 합니다.

버전 3.1에서 변경: rename에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: verbose와 rename 매개 변수는 키워드 전용 인자가 되었습니다.

버전 3.6에서 변경: module 매개 변수를 추가했습니다.

버전 3.7에서 변경: verbose 매개 변수와 _source 어트리뷰트를 제거했습니다.

버전 3.7에서 변경: defaults 매개 변수와 _field_defaults 어트리뷰트가 추가되었습니다.

>>> # Basic example
>>> Point = namedtuple('Point', ['x', 'y'])
>>> p = Point(11, y=22)     # instantiate with positional or keyword arguments
>>> p[0] + p[1]             # indexable like the plain tuple (11, 22)
33
>>> x, y = p                # unpack like a regular tuple
>>> x, y
(11, 22)
>>> p.x + p.y               # fields also accessible by name
33
>>> p                       # readable __repr__ with a name=value style
Point(x=11, y=22)

네임드 튜플은 csv 나 sqlite3 모듈이 반환한 결과 튜플에 필드 이름을 할당하는 데 특히 유용합니다:

EmployeeRecord = namedtuple('EmployeeRecord', 'name, age, title, department, paygrade')

import csv
for emp in map(EmployeeRecord._make, csv.reader(open("employees.csv", "rb"))):
    print(emp.name, emp.title)

import sqlite3
conn = sqlite3.connect('/companydata')
cursor = conn.cursor()
cursor.execute('SELECT name, age, title, department, paygrade FROM employees')
for emp in map(EmployeeRecord._make, cursor.fetchall()):
    print(emp.name, emp.title)

튜플에서 상속된 메서드 외에도 네임드 튜플은 세 가지 추가 메서드와 두 가지 어트리뷰트를 지원합니다. 필드 이름과의 충돌을 방지하기 위해, 메서드와 어트리뷰트 이름은 밑줄로 시작합니다.

classmethod somenamedtuple._make(iterable)

기존 시퀀스나 이터러블로 새 인스턴스를 만드는 클래스 메서드.

>>> t = [11, 22]
>>> Point._make(t)
Point(x=11, y=22)

somenamedtuple._asdict()

필드 이름을 해당 값으로 매핑하는 새 dict를 반환합니다:

>>> p = Point(x=11, y=22)
>>> p._asdict()
{'x': 11, 'y': 22}

버전 3.1에서 변경: 일반 dict 대신 OrderedDict를 반환합니다.

버전 3.8에서 변경: OrderedDict 대신 일반 dict를 반환합니다. 파이썬 3.7부터, 일반 딕셔너리의 순서가 유지되도록 보장합니다. OrderedDict의 추가 기능이 필요할 때, 제안하는 처방은 결과를 원하는 형으로 캐스트 하는 것입니다: OrderedDict(nt._asdict()).

somenamedtuple._replace(**kwargs)

지정된 필드들을 새로운 값으로 치환하는 네임드 튜플의 새 인스턴스를 반환합니다:

>>> p = Point(x=11, y=22)
>>> p._replace(x=33)
Point(x=33, y=22)

>>> for partnum, record in inventory.items():
...     inventory[partnum] = record._replace(price=newprices[partnum], timestamp=time.now())

Named tuples are also supported by generic function copy.replace().

버전 3.13에서 변경: Raise TypeError instead of ValueError for invalid keyword arguments.

somenamedtuple._fields

필드 이름을 나열하는 문자열의 튜플. 인트로스펙션과 기존 네임드 튜플에서 새로운 네임드 튜플 형을 만드는 데 유용합니다.

>>> p._fields            # view the field names
('x', 'y')

>>> Color = namedtuple('Color', 'red green blue')
>>> Pixel = namedtuple('Pixel', Point._fields + Color._fields)
>>> Pixel(11, 22, 128, 255, 0)
Pixel(x=11, y=22, red=128, green=255, blue=0)

somenamedtuple._field_defaults

필드 이름을 기본값으로 매핑하는 딕셔너리.

>>> Account = namedtuple('Account', ['type', 'balance'], defaults=[0])
>>> Account._field_defaults
{'balance': 0}
>>> Account('premium')
Account(type='premium', balance=0)

이름이 문자열에 저장된 필드를 조회하려면 getattr() 함수를 사용하십시오.:

>>> getattr(p, 'x')
11

딕셔너리를 네임드 튜플로 변환하려면 이중 애스터리스크 연산자를 사용하십시오 (인자 목록 언 패킹에서 설명합니다).:

>>> d = {'x': 11, 'y': 22}
>>> Point(**d)
Point(x=11, y=22)

네임드 튜플은 일반적인 파이썬 클래스이므로, 서브 클래스를 사용하여 기능을 쉽게 추가하거나 변경할 수 있습니다. 계산된 필드와 고정 너비 인쇄 포맷을 추가하는 방법은 다음과 같습니다:

>>> class Point(namedtuple('Point', ['x', 'y'])):
...     __slots__ = ()
...     @property
...     def hypot(self):
...         return (self.x ** 2 + self.y ** 2) ** 0.5
...     def __str__(self):
...         return 'Point: x=%6.3f  y=%6.3f  hypot=%6.3f' % (self.x, self.y, self.hypot)

>>> for p in Point(3, 4), Point(14, 5/7):
...     print(p)
Point: x= 3.000  y= 4.000  hypot= 5.000
Point: x=14.000  y= 0.714  hypot=14.018

위에 표시된 서브 클래스는 __slots__를 빈 튜플로 설정합니다. 이렇게 하면 인스턴스 딕셔너리 생성을 방지하여 메모리 요구 사항을 낮게 유지할 수 있습니다.

서브 클래싱은 저장된 새 필드를 추가하는 데는 유용하지 않습니다. 대신, _fields 어트리뷰트로 새로운 네임드 튜플 형을 만드십시오:

>>> Point3D = namedtuple('Point3D', Point._fields + ('z',))

__doc__ 필드에 직접 대입하여 독스트링을 사용자 정의할 수 있습니다:

>>> Book = namedtuple('Book', ['id', 'title', 'authors'])
>>> Book.__doc__ += ': Hardcover book in active collection'
>>> Book.id.__doc__ = '13-digit ISBN'
>>> Book.title.__doc__ = 'Title of first printing'
>>> Book.authors.__doc__ = 'List of authors sorted by last name'

버전 3.5에서 변경: 프로퍼티 독스트링이 쓰기 가능하게 되었습니다.

더 보기

네임드 튜플에 형 힌트를 추가하는 방법은 typing.NamedTuple을 참조하십시오. 이것은 class 키워드를 사용하는 우아한 표기법도 제공합니다:

class Component(NamedTuple):
    part_number: int
    weight: float
    description: Optional[str] = None

튜플 대신 하부 딕셔너리를 기반으로 하는 가변 이름 공간에 대해서는 types.SimpleNamespace()를 참조하십시오.

dataclasses 모듈은 사용자 정의 클래스에 생성된 특수 메서드를 자동으로 추가하는 데코레이터와 함수를 제공합니다.

OrderedDict 객체

순서 있는 딕셔너리는 일반 딕셔너리와 비슷하지만, 순서를 다루는 연산과 관련된 몇 가지 추가 기능이 있습니다. 내장 dict 클래스가 삽입 순서를 기억하는 기능을 얻었으므로 (이 새로운 동작은 파이썬 3.7에서 보장되었습니다), 이제 덜 중요해졌습니다.

몇 가지 dict와의 차이점은 여전히 남아 있습니다:

일반 dict는 매핑 연산에 매우 적합하도록 설계되었습니다. 삽입 순서 추적은 부차적입니다.

OrderedDict는 순서를 바꾸는 연산에 적합하도록 설계되었습니다. 공간 효율성, 이터레이션 속도 및 갱신 연산의 성능은 부차적입니다.

The OrderedDict algorithm can handle frequent reordering operations better than dict. As shown in the recipes below, this makes it suitable for implementing various kinds of LRU caches.

OrderedDict의 동등 비교 연산은 순서의 일치를 확인합니다.

A regular dict can emulate the order sensitive equality test with p == q and all(k1 == k2 for k1, k2 in zip(p, q)).

OrderedDict의 popitem() 메서드는 서명이 다릅니다. 어떤 항목을 팝 할지는 지정하는 선택적 인자를 받아들입니다.

A regular dict can emulate OrderedDict’s od.popitem(last=True) with d.popitem() which is guaranteed to pop the rightmost (last) item.

A regular dict can emulate OrderedDict’s od.popitem(last=False) with (k := next(iter(d)), d.pop(k)) which will return and remove the leftmost (first) item if it exists.

OrderedDict에는 요소를 효율적으로 끝으로 재배치하는 move_to_end() 메서드가 있습니다.

A regular dict can emulate OrderedDict’s od.move_to_end(k, last=True) with d[k] = d.pop(k) which will move the key and its associated value to the rightmost (last) position.

A regular dict does not have an efficient equivalent for OrderedDict’s od.move_to_end(k, last=False) which moves the key and its associated value to the leftmost (first) position.

파이썬 3.8 이전에는, dict에 __reversed__() 메서드가 없었습니다.

class collections.OrderedDict([items])

딕셔너리 순서 재배치에 특화된 메서드가 있는 dict 서브 클래스의 인스턴스를 반환합니다.

Added in version 3.1.

popitem(last=True)

순서 있는 딕셔너리의 popitem() 메서드는 (키, 값) 쌍을 반환하고 제거합니다. last가 참이면 쌍이 LIFO 순서로 반환되고, 거짓이면 FIFO 순서로 반환됩니다.

move_to_end(key, last=True)

Move an existing key to either end of an ordered dictionary. The item is moved to the right end if last is true (the default) or to the beginning if last is false. Raises KeyError if the key does not exist:

>>> d = OrderedDict.fromkeys('abcde')
>>> d.move_to_end('b')
>>> ''.join(d)
'acdeb'
>>> d.move_to_end('b', last=False)
>>> ''.join(d)
'bacde'

Added in version 3.2.

일반적인 매핑 메서드 외에도 순서 있는 딕셔너리는 reversed()를 사용하는 역 이터레이션을 지원합니다.

Equality tests between OrderedDict objects are order-sensitive and are roughly equivalent to list(od1.items())==list(od2.items()).

Equality tests between OrderedDict objects and other Mapping objects are order-insensitive like regular dictionaries. This allows OrderedDict objects to be substituted anywhere a regular dictionary is used.

버전 3.5에서 변경: OrderedDict의 items, keys 및 values 뷰는 이제 reversed()를 사용하는 역 이터레이션을 지원합니다.

버전 3.6에서 변경: PEP 468 [https://peps.python.org/pep-0468/]을 수락함에 따라, OrderedDict 생성자와 update() 메서드로 전달된 키워드 인자의 순서가 보존됩니다.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]에 지정된, 병합(|)과 업데이트(|=) 연산자가 추가되었습니다.

OrderedDict 예제와 조리법

키가 마지막에 삽입된 순서를 기억하는 순서 있는 딕셔너리 변형을 만드는 것은 간단합니다. 새 항목이 기존 항목을 덮어쓰면, 원래 삽입 위치가 변경되고 끝으로 이동합니다:

class LastUpdatedOrderedDict(OrderedDict):
    'Store items in the order the keys were last added'

    def __setitem__(self, key, value):
        super().__setitem__(key, value)
        self.move_to_end(key)

An OrderedDict would also be useful for implementing variants of functools.lru_cache():

from collections import OrderedDict
from time import time

class TimeBoundedLRU:
    "LRU Cache that invalidates and refreshes old entries."

    def __init__(self, func, maxsize=128, maxage=30):
        self.cache = OrderedDict()      # { args : (timestamp, result)}
        self.func = func
        self.maxsize = maxsize
        self.maxage = maxage

    def __call__(self, *args):
        if args in self.cache:
            self.cache.move_to_end(args)
            timestamp, result = self.cache[args]
            if time() - timestamp <= self.maxage:
                return result
        result = self.func(*args)
        self.cache[args] = time(), result
        if len(self.cache) > self.maxsize:
            self.cache.popitem(last=False)
        return result

class MultiHitLRUCache:
    """ LRU cache that defers caching a result until
        it has been requested multiple times.

        To avoid flushing the LRU cache with one-time requests,
        we don't cache until a request has been made more than once.

    """

    def __init__(self, func, maxsize=128, maxrequests=4096, cache_after=1):
        self.requests = OrderedDict()   # { uncached_key : request_count }
        self.cache = OrderedDict()      # { cached_key : function_result }
        self.func = func
        self.maxrequests = maxrequests  # max number of uncached requests
        self.maxsize = maxsize          # max number of stored return values
        self.cache_after = cache_after

    def __call__(self, *args):
        if args in self.cache:
            self.cache.move_to_end(args)
            return self.cache[args]
        result = self.func(*args)
        self.requests[args] = self.requests.get(args, 0) + 1
        if self.requests[args] <= self.cache_after:
            self.requests.move_to_end(args)
            if len(self.requests) > self.maxrequests:
                self.requests.popitem(last=False)
        else:
            self.requests.pop(args, None)
            self.cache[args] = result
            if len(self.cache) > self.maxsize:
                self.cache.popitem(last=False)
        return result

UserDict 객체

UserDict 클래스는 딕셔너리 객체를 감싸는 래퍼 역할을 합니다. 이 클래스의 필요성은 dict에서 직접 서브 클래싱 할 수 있는 능력에 의해 부분적으로 대체되었습니다; 그러나 하부 딕셔너리를 어트리뷰트로 액세스 할 수 있어서, 이 클래스를 사용하면 작업하기가 더 쉬울 수 있습니다.

class collections.UserDict([initialdata])

Class that simulates a dictionary. The instance’s contents are kept in a regular dictionary, which is accessible via the data attribute of UserDict instances. If initialdata is provided, data is initialized with its contents; note that a reference to initialdata will not be kept, allowing it to be used for other purposes.

UserDict 인스턴스는 매핑의 메서드와 연산을 지원할 뿐만 아니라, 다음과 같은 어트리뷰트를 제공합니다:

data

UserDict 클래스의 내용을 저장하는 데 사용되는 실제 딕셔너리.

UserList 객체

이 클래스는 리스트 객체를 둘러싸는 래퍼 역할을 합니다. 여러분 자신의 리스트류 클래스가 상속하고 기존 메서드를 재정의하거나 새로운 메서드를 추가할 수 있는 유용한 베이스 클래스입니다. 이런 식으로 리스트에 새로운 동작을 추가 할 수 있습니다.

이 클래스의 필요성은 list에서 직접 서브 클래싱할 수 있는 능력에 의해 부분적으로 대체되었습니다; 그러나 하부 리스트에 어트리뷰트로 액세스할 수 있어서, 이 클래스를 사용하면 작업하기가 더 쉬울 수 있습니다.

class collections.UserList([list])

리스트를 시뮬레이트 하는 클래스. 인스턴스의 내용은 일반 리스트로 유지되며 UserList 인스턴스의 data 어트리뷰트를 통해 액세스 할 수 있습니다. 인스턴스의 내용은 초기에 list의 사본으로 설정되며, 기본값은 빈 목록 []입니다. list는 모든 이터러블일 수 있습니다, 예를 들어 실제 파이썬 리스트나 UserList 객체.

UserList 인스턴스는 가변 시퀀스의 메서드와 연산을 지원할 뿐만 아니라 다음 어트리뷰트를 제공합니다:

data

UserList 클래스의 내용을 저장하는 데 사용되는 실제 list 객체.

서브 클래싱 요구 사항: UserList의 서브 클래스는 인자가 없거나 하나의 인자로 호출 할 수 있는 생성자를 제공해야 합니다. 새 시퀀스를 반환하는 리스트 연산은 실제 구현 클래스의 인스턴스를 만들려고 시도합니다. 이를 위해, 데이터 소스로 사용되는 시퀀스 객체인 단일 매개 변수로 생성자를 호출할 수 있다고 가정합니다.

파생 클래스가 이 요구 사항을 준수하고 싶지 않다면, 이 클래스에서 지원하는 모든 특수 메서드를 재정의해야 합니다; 이때 제공해야 하는 메서드에 대한 정보는 소스를 참조하십시오.

UserString 객체

UserString 클래스는 문자열 객체를 둘러싸는 래퍼 역할을 합니다. 이 클래스의 필요성은 str에서 직접 서브 클래싱할 수 있는 능력에 의해 부분적으로 대체되었습니다; 그러나 하부 문자열을 어트리뷰트로 액세스할 수 있어서, 이 클래스를 사용하면 작업하기가 더 쉬울 수 있습니다.

class collections.UserString(seq)

문자열 객체를 시뮬레이트 하는 클래스. 인스턴스의 내용은 일반 문자열 객체로 유지되며, UserString 인스턴스의 data 어트리뷰트를 통해 액세스 할 수 있습니다. 인스턴스의 내용은 처음에 seq의 사본으로 설정됩니다. seq 인자는 내장 str() 함수를 사용하여 문자열로 변환 할 수 있는 모든 객체가 될 수 있습니다.

UserString 인스턴스는 문자열의 메서드와 연산을 지원할 뿐만 아니라 다음과 같은 어트리뷰트를 제공합니다:

data

UserString 클래스의 내용을 저장하는 데 사용되는 실제 str 객체.

버전 3.5에서 변경: 새로운 메서드 __getnewargs__, __rmod__, casefold, format_map, isprintable 및 maketrans.

collections.abc — Abstract Base Classes for Containers

Added in version 3.3: 이전에는, 이 모듈이 collections 모듈의 일부였습니다.

소스 코드: Lib/_collections_abc.py [https://github.com/python/cpython/tree/main/Lib/_collections_abc.py]

This module provides abstract base classes that can be used to test whether a class provides a particular interface; for example, whether it is hashable or whether it is a mapping.

An issubclass() or isinstance() test for an interface works in one of three ways.

1) A newly written class can inherit directly from one of the abstract base classes. The class must supply the required abstract methods. The remaining mixin methods come from inheritance and can be overridden if desired. Other methods may be added as needed:

class C(Sequence):                      # Direct inheritance
    def __init__(self): ...             # Extra method not required by the ABC
    def __getitem__(self, index):  ...  # Required abstract method
    def __len__(self):  ...             # Required abstract method
    def count(self, value): ...         # Optionally override a mixin method

>>> issubclass(C, Sequence)
True
>>> isinstance(C(), Sequence)
True

2) Existing classes and built-in classes can be registered as “virtual subclasses” of the ABCs. Those classes should define the full API including all of the abstract methods and all of the mixin methods. This lets users rely on issubclass() or isinstance() tests to determine whether the full interface is supported. The exception to this rule is for methods that are automatically inferred from the rest of the API:

class D:                                 # No inheritance
    def __init__(self): ...              # Extra method not required by the ABC
    def __getitem__(self, index):  ...   # Abstract method
    def __len__(self):  ...              # Abstract method
    def count(self, value): ...          # Mixin method
    def index(self, value): ...          # Mixin method

Sequence.register(D)                     # Register instead of inherit

>>> issubclass(D, Sequence)
True
>>> isinstance(D(), Sequence)
True

In this example, class D does not need to define __contains__, __iter__, and __reversed__ because the in-operator, the iteration logic, and the reversed() function automatically fall back to using __getitem__ and __len__.

3) Some simple interfaces are directly recognizable by the presence of the required methods (unless those methods have been set to None):

class E:
    def __iter__(self): ...
    def __next__(self): ...

>>> issubclass(E, Iterable)
True
>>> isinstance(E(), Iterable)
True

Complex interfaces do not support this last technique because an interface is more than just the presence of method names. Interfaces specify semantics and relationships between methods that cannot be inferred solely from the presence of specific method names. For example, knowing that a class supplies __getitem__, __len__, and __iter__ is insufficient for distinguishing a Sequence from a Mapping.

Added in version 3.9: These abstract classes now support []. See 제네릭 에일리어스 형 and PEP 585 [https://peps.python.org/pep-0585/].

Collections 추상 베이스 클래스

collections 모듈은 다음과 같은 ABC를 제공합니다:

ABC

상속

추상 메서드

믹스인 메서드

Container [1]

__contains__

Hashable [1]

__hash__

Iterable [1] [2]

__iter__

Iterator [1]

Iterable

__next__

__iter__

Reversible [1]

Iterable

__reversed__

Generator [1]

Iterator

send, throw

close, __iter__, __next__

Sized [1]

__len__

Callable [1]

__call__

Collection [1]

Sized, Iterable, Container

__contains__, __iter__, __len__

Sequence

Reversible, Collection

__getitem__, __len__

__contains__, __iter__, __reversed__, index 및 count

MutableSequence

Sequence

__getitem__, __setitem__, __delitem__, __len__, insert

Inherited Sequence methods and append, clear, reverse, extend, pop, remove, and __iadd__

Set

Collection

__contains__, __iter__, __len__

__le__, __lt__, __eq__, __ne__, __gt__, __ge__, __and__, __or__, __sub__, __rsub__, __xor__, __rxor__ and isdisjoint

MutableSet

Set

__contains__, __iter__, __len__, add, discard

상속된 Set 메서드와 clear, pop, remove, __ior__, __iand__, __ixor__ 및 __isub__

Mapping

Collection

__getitem__, __iter__, __len__

__contains__, keys, items, values, get, __eq__ 및 __ne__

MutableMapping

Mapping

__getitem__, __setitem__, __delitem__, __iter__, __len__

상속된 Mapping 메서드와 pop, popitem, clear, update 및 setdefault

MappingView

Sized

__init__, __len__ and __repr__

ItemsView

MappingView, Set

__contains__, __iter__

KeysView

MappingView, Set

__contains__, __iter__

ValuesView

MappingView, Collection

__contains__, __iter__

Awaitable [1]

__await__

Coroutine [1]

Awaitable

send, throw

close

AsyncIterable [1]

__aiter__

AsyncIterator [1]

AsyncIterable

__anext__

__aiter__

AsyncGenerator [1]

AsyncIterator

asend, athrow

aclose, __aiter__, __anext__

Buffer [1]

__buffer__

Footnotes

[1] (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)

These ABCs override __subclasshook__() to support testing an interface by verifying the required methods are present and have not been set to None. This only works for simple interfaces. More complex interfaces require registration or direct subclassing.

[2]

Checking isinstance(obj, Iterable) detects classes that are registered as Iterable or that have an __iter__() method, but it does not detect classes that iterate with the __getitem__() method. The only reliable way to determine whether an object is iterable is to call iter(obj).

Collections Abstract Base Classes – Detailed Descriptions

class collections.abc.Container

ABC for classes that provide the __contains__() method.

class collections.abc.Hashable

ABC for classes that provide the __hash__() method.

class collections.abc.Sized

ABC for classes that provide the __len__() method.

class collections.abc.Callable

ABC for classes that provide the __call__() method.

See Annotating callable objects for details on how to use Callable in type annotations.

class collections.abc.Iterable

ABC for classes that provide the __iter__() method.

Checking isinstance(obj, Iterable) detects classes that are registered as Iterable or that have an __iter__() method, but it does not detect classes that iterate with the __getitem__() method. The only reliable way to determine whether an object is iterable is to call iter(obj).

class collections.abc.Collection

길이가 있는 이터러블 컨테이너 클래스의 ABC.

Added in version 3.6.

class collections.abc.Iterator

__iter__() 와 __next__() 메서드를 제공하는 클래스의 ABC. 이터레이터의 정의도 참조하십시오.

class collections.abc.Reversible

ABC for iterable classes that also provide the __reversed__() method.

Added in version 3.6.

class collections.abc.Generator

ABC for generator classes that implement the protocol defined in PEP 342 [https://peps.python.org/pep-0342/] that extends iterators with the send(), throw() and close() methods.

See Annotating generators and coroutines for details on using Generator in type annotations.

Added in version 3.5.

class collections.abc.Sequence

class collections.abc.MutableSequence

읽기 전용과 가변 시퀀스의 ABC.

Implementation note: Some of the mixin methods, such as __iter__(), __reversed__() and index(), make repeated calls to the underlying __getitem__() method. Consequently, if __getitem__() is implemented with constant access speed, the mixin methods will have linear performance; however, if the underlying method is linear (as it would be with a linked list), the mixins will have quadratic performance and will likely need to be overridden.

버전 3.5에서 변경: index() 메서드는 stop과 start 인자에 대한 지원을 추가했습니다.

class collections.abc.Set

class collections.abc.MutableSet

ABCs for read-only and mutable sets.

class collections.abc.Mapping

class collections.abc.MutableMapping

읽기 전용과 가변 매핑의 ABC.

class collections.abc.MappingView

class collections.abc.ItemsView

class collections.abc.KeysView

class collections.abc.ValuesView

매핑, 항목, 키 및 값 뷰의 ABC.

class collections.abc.Awaitable

ABC for awaitable objects, which can be used in await expressions. Custom implementations must provide the __await__() method.

코루틴 객체와 Coroutine ABC의 인스턴스는 모두 이 ABC의 인스턴스입니다.

참고

In CPython, generator-based coroutines (generators decorated with @types.coroutine) are awaitables, even though they do not have an __await__() method. Using isinstance(gencoro, Awaitable) for them will return False. Use inspect.isawaitable() to detect them.

Added in version 3.5.

class collections.abc.Coroutine

ABC for coroutine compatible classes. These implement the following methods, defined in 코루틴 객체(Coroutine Objects): send(), throw(), and close(). Custom implementations must also implement __await__(). All Coroutine instances are also instances of Awaitable.

참고

In CPython, generator-based coroutines (generators decorated with @types.coroutine) are awaitables, even though they do not have an __await__() method. Using isinstance(gencoro, Coroutine) for them will return False. Use inspect.isawaitable() to detect them.

See Annotating generators and coroutines for details on using Coroutine in type annotations. The variance and order of type parameters correspond to those of Generator.

Added in version 3.5.

class collections.abc.AsyncIterable

ABC for classes that provide an __aiter__ method. See also the definition of asynchronous iterable.

Added in version 3.5.

class collections.abc.AsyncIterator

__aiter__ 와 __anext__ 메서드를 제공하는 클래스의 ABC. 비동기 이터레이터의 정의도 참조하십시오.

Added in version 3.5.

class collections.abc.AsyncGenerator

ABC for asynchronous generator classes that implement the protocol defined in PEP 525 [https://peps.python.org/pep-0525/] and PEP 492 [https://peps.python.org/pep-0492/].

See Annotating generators and coroutines for details on using AsyncGenerator in type annotations.

Added in version 3.6.

class collections.abc.Buffer

ABC for classes that provide the __buffer__() method, implementing the buffer protocol. See PEP 688 [https://peps.python.org/pep-0688/].

Added in version 3.12.

Examples and Recipes

ABCs allow us to ask classes or instances if they provide particular functionality, for example:

size = None
if isinstance(myvar, collections.abc.Sized):
    size = len(myvar)

Several of the ABCs are also useful as mixins that make it easier to develop classes supporting container APIs. For example, to write a class supporting the full Set API, it is only necessary to supply the three underlying abstract methods: __contains__(), __iter__(), and __len__(). The ABC supplies the remaining methods such as __and__() and isdisjoint():

class ListBasedSet(collections.abc.Set):
    ''' Alternate set implementation favoring space over speed
        and not requiring the set elements to be hashable. '''
    def __init__(self, iterable):
        self.elements = lst = []
        for value in iterable:
            if value not in lst:
                lst.append(value)

    def __iter__(self):
        return iter(self.elements)

    def __contains__(self, value):
        return value in self.elements

    def __len__(self):
        return len(self.elements)

s1 = ListBasedSet('abcdef')
s2 = ListBasedSet('defghi')
overlap = s1 & s2            # The __and__() method is supported automatically

Set과 MutableSet을 믹스인으로 사용할 때의 주의 사항:

Since some set operations create new sets, the default mixin methods need a way to create new instances from an iterable. The class constructor is assumed to have a signature in the form ClassName(iterable). That assumption is factored-out to an internal classmethod called _from_iterable() which calls cls(iterable) to produce a new set. If the Set mixin is being used in a class with a different constructor signature, you will need to override _from_iterable() with a classmethod or regular method that can construct new instances from an iterable argument.

To override the comparisons (presumably for speed, as the semantics are fixed), redefine __le__() and __ge__(), then the other operations will automatically follow suit.

The Set mixin provides a _hash() method to compute a hash value for the set; however, __hash__() is not defined because not all sets are hashable or immutable. To add set hashability using mixins, inherit from both Set() and Hashable(), then define __hash__ = Set._hash.

더 보기

MutableSet으로 구축한 예제 OrderedSet 조리법 [https://code.activestate.com/recipes/576694/].

ABC에 대한 자세한 내용은, abc 모듈과 PEP 3119 [https://peps.python.org/pep-3119/]를 참조하십시오.

heapq — Heap queue algorithm

소스 코드: Lib/heapq.py [https://github.com/python/cpython/tree/main/Lib/heapq.py]

이 모듈은 우선순위 큐 알고리즘이라고도 하는 힙(heap) 큐 알고리즘의 구현을 제공합니다.

Heaps are binary trees for which every parent node has a value less than or equal to any of its children. We refer to this condition as the heap invariant.

This implementation uses arrays for which heap[k] <= heap[2*k+1] and heap[k] <= heap[2*k+2] for all k, counting elements from zero. For the sake of comparison, non-existing elements are considered to be infinite. The interesting property of a heap is that its smallest element is always the root, heap[0].

아래의 API는 두 가지 측면에서 교과서 힙 알고리즘과 다릅니다: (a) 우리는 0부터 시작하는 인덱싱을 사용합니다. 이것은 노드의 인덱스와 자식의 인덱스 사이의 관계를 약간 덜 분명하게 만들지만, 파이썬이 0부터 시작하는 인덱스를 사용하기 때문에 더 적합합니다. (b) pop 메서드는 가장 큰 항목이 아닌 가장 작은 항목을 반환합니다 (교과서에서는 “최소 힙(min heap)”이라고 합니다; “최대 힙(max heap)”은 제자리 정렬에 적합하기 때문에 텍스트에서 더 흔합니다).

이 두 가지가 힙을 놀라지 않고도 일반 파이썬 목록으로 볼 수 있도록 만듭니다: heap[0]은 가장 작은 항목이고, heap.sort()는 힙의 불변성(invariant)을 유지합니다!

힙을 만들려면, []로 초기화된 리스트를 사용하거나, 함수 heapify()를 통해 값이 들어 있는 리스트를 힙으로 변환 할 수 있습니다.

다음과 같은 함수가 제공됩니다:

heapq.heappush(heap, item)

힙 불변성을 유지하면서, item 값을 heap으로 푸시합니다.

heapq.heappop(heap)

힙 불변성을 유지하면서, heap에서 가장 작은 항목을 팝하고 반환합니다. 힙이 비어 있으면, IndexError가 발생합니다. 팝 하지 않고 가장 작은 항목에 액세스하려면, heap[0]을 사용하십시오.

heapq.heappushpop(heap, item)

힙에 item을 푸시한 다음, heap에서 가장 작은 항목을 팝하고 반환합니다. 결합한 액션은 heappush()한 다음 heappop()을 별도로 호출하는 것보다 더 효율적으로 실행합니다.

heapq.heapify(x)

리스트 x를 선형 시간으로 제자리에서 힙으로 변환합니다.

heapq.heapreplace(heap, item)

heap에서 가장 작은 항목을 팝하고 반환하며, 새로운 item도 푸시합니다. 힙 크기는 변경되지 않습니다. 힙이 비어 있으면, IndexError가 발생합니다.

이 한 단계 연산은 heappop()한 다음 heappush()하는 것보다 더 효율적이며 고정 크기 힙을 사용할 때 더 적합 할 수 있습니다. 팝/푸시 조합은 항상 힙에서 요소를 반환하고 그것을 item으로 대체합니다.

반환된 값은 추가된 item보다 클 수 있습니다. 그것이 바람직하지 않다면, 대신 heappushpop() 사용을 고려하십시오. 푸시/팝 조합은 두 값 중 작은 값을 반환하여, 힙에 큰 값을 남겨 둡니다.

이 모듈은 또한 힙 기반의 세 가지 범용 함수를 제공합니다.

heapq.merge(*iterables, key=None, reverse=False)

여러 정렬된 입력을 단일 정렬된 출력으로 병합합니다 (예를 들어, 여러 로그 파일에서 타임 스탬프 된 항목을 병합합니다). 정렬된 값에 대한 이터레이터를 반환합니다.

sorted(itertools.chain(*iterables))와 비슷하지만 이터러블을 반환하고, 데이터를 한 번에 메모리로 가져오지 않으며, 각 입력 스트림이 이미 (최소에서 최대로) 정렬된 것으로 가정합니다.

키워드 인자로 지정해야 하는 두 개의 선택적 인자가 있습니다.

key는 각 입력 요소에서 비교 키를 추출하는 데 사용되는 단일 인자의 키 함수를 지정합니다. 기본값은 None입니다 (요소를 직접 비교합니다).

reverse는 불리언 값입니다. True로 설정하면, 각 비교가 반대로 된 것처럼 입력 요소가 병합됩니다. sorted(itertools.chain(*iterables), reverse=True)와 유사한 동작을 달성하려면 모든 이터러블이 최대에서 최소로 정렬되어 있어야 합니다.

버전 3.5에서 변경: 선택적 key와 reverse 매개 변수를 추가했습니다.

heapq.nlargest(n, iterable, key=None)

iterable에 의해 정의된 데이터 집합에서 n 개의 가장 큰 요소로 구성된 리스트를 반환합니다. key가 제공되면 iterable의 각 요소에서 비교 키를 추출하는 데 사용되는 단일 인자 함수를 지정합니다 (예를 들어, key=str.lower). 다음과 동등합니다: sorted(iterable, key=key, reverse=True)[:n].

heapq.nsmallest(n, iterable, key=None)

iterable에 의해 정의된 데이터 집합에서 n 개의 가장 작은 요소로 구성된 리스트를 반환합니다. key가 제공되면 iterable의 각 요소에서 비교 키를 추출하는 데 사용되는 단일 인자 함수를 지정합니다 (예를 들어, key=str.lower). 다음과 동등합니다: sorted(iterable, key=key)[:n].

마지막 두 함수는 작은 n 값에서 가장 잘 동작합니다. 값이 크면, sorted() 기능을 사용하는 것이 더 효율적입니다. 또한, n==1일 때는, 내장 min()과 max() 함수를 사용하는 것이 더 효율적입니다. 이 함수를 반복해서 사용해야 하면, iterable을 실제 힙으로 바꾸는 것이 좋습니다.

기본 예

힙 정렬 [https://en.wikipedia.org/wiki/Heapsort]은 모든 값을 힙으로 푸시한 다음 한 번에 하나씩 가장 작은 값을 팝 하여 구현할 수 있습니다:

>>> def heapsort(iterable):
...     h = []
...     for value in iterable:
...         heappush(h, value)
...     return [heappop(h) for i in range(len(h))]
...
>>> heapsort([1, 3, 5, 7, 9, 2, 4, 6, 8, 0])
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

이것은 sorted(iterable)과 비슷하지만, sorted()와 달리, 이 구현은 안정적(stable)이지 않습니다.

힙 요소는 튜플일 수 있습니다. 추적하는 기본 레코드와 함께 비교 값(가령 작업 우선순위)을 지정하는 데 유용합니다:

>>> h = []
>>> heappush(h, (5, 'write code'))
>>> heappush(h, (7, 'release product'))
>>> heappush(h, (1, 'write spec'))
>>> heappush(h, (3, 'create tests'))
>>> heappop(h)
(1, 'write spec')

우선순위 큐 구현 참고 사항

우선순위 큐 [https://en.wikipedia.org/wiki/Priority_queue]는 힙의 일반적인 사용이며, 몇 가지 구현 과제가 있습니다:

정렬 안정성: 우선순위가 같은 두 개의 작업을 어떻게 원래 추가된 순서대로 반환합니까?

우선순위가 같고 작업에 기본 비교 순서가 없으면 (우선순위, 작업) 쌍에 대한 튜플 비교가 성립하지 않습니다.

작업의 우선순위가 변경되면, 어떻게 힙의 새로운 위치로 옮깁니까?

또는 계류 중인 작업을 삭제해야 하면, 작업을 어떻게 찾고 큐에서 제거합니까?

처음 두 가지 과제에 대한 해결책은 항목을 우선순위, 항목 수 및 작업을 포함하는 3-요소 리스트로 저장하는 것입니다. 항목 수는 순위 결정자 역할을 하므로 우선순위가 같은 두 작업이 추가된 순서대로 반환됩니다. 두 항목 수가 같은 경우는 없어서, 튜플 비교는 두 작업을 직접 비교하려고 하지 않습니다.

비교할 수 없는 작업의 문제에 대한 또 다른 해결책은 작업 항목을 무시하고 우선순위 필드만 비교하는 래퍼 클래스를 만드는 것입니다:

from dataclasses import dataclass, field
from typing import Any

@dataclass(order=True)
class PrioritizedItem:
    priority: int
    item: Any=field(compare=False)

나머지 과제는 계류 중인 작업을 찾고 우선순위를 변경하거나 완전히 제거하는 것과 관련이 있습니다. 작업을 찾는 것은 큐에 있는 항목을 가리키는 딕셔너리를 사용해서 해결할 수 있습니다.

힙 구조 불변성을 깨뜨리기 때문에 항목을 제거하거나 우선순위를 변경하는 것은 더 어렵습니다. 따라서, 가능한 해결책은 항목을 제거된 것으로 표시하고 우선순위가 수정된 새 항목을 추가하는 것입니다:

pq = []                         # list of entries arranged in a heap
entry_finder = {}               # mapping of tasks to entries
REMOVED = '<removed-task>'      # placeholder for a removed task
counter = itertools.count()     # unique sequence count

def add_task(task, priority=0):
    'Add a new task or update the priority of an existing task'
    if task in entry_finder:
        remove_task(task)
    count = next(counter)
    entry = [priority, count, task]
    entry_finder[task] = entry
    heappush(pq, entry)

def remove_task(task):
    'Mark an existing task as REMOVED.  Raise KeyError if not found.'
    entry = entry_finder.pop(task)
    entry[-1] = REMOVED

def pop_task():
    'Remove and return the lowest priority task. Raise KeyError if empty.'
    while pq:
        priority, count, task = heappop(pq)
        if task is not REMOVED:
            del entry_finder[task]
            return task
    raise KeyError('pop from an empty priority queue')

이론

힙은 0부터 요소를 셀 때, 모든 k에 대해 a[k] <= a[2*k+1]와 a[k] <= a[2*k+2]가 유지되는 배열입니다. 비교를 위해, 존재하지 않는 요소는 무한인 것으로 간주합니다. 힙의 흥미로운 특성은 a[0]이 항상 가장 작은 요소라는 것입니다.

위의 특이한 불변성은 토너먼트를 위한 효율적인 메모리 표현을 위한 것입니다. 아래 숫자는 a[k]가 아니라 k입니다:

                               0

              1                                 2

      3               4                5               6

  7       8       9       10      11      12      13      14

15 16   17 18   19 20   21 22   23 24   25 26   27 28   29 30

위의 트리에서, 각 셀 k는 2*k+1과 2*k+2위에 있습니다. 우리가 스포츠에서 볼 수 있는 일반적인 이진 토너먼트에서, 각 셀은 아래에 있는 두 개의 셀의 승자가 되며, 트리 아래로 승자를 추적하여 모든 상대를 볼 수 있습니다. 그러나, 이러한 토너먼트의 많은 컴퓨터 응용에서 승자의 이력을 추적할 필요는 없습니다. 메모리 효율성을 높이기 위해, 승자가 승격될 때, 하위 수준에서 다른 것으로 대체하려고 시도합니다. 규칙은 셀과 셀 아래의 두 셀이 세 개의 다른 항목을 포함하지만, 위의 셀은 아래의 두 셀에 “이기는” 것입니다.

If this heap invariant is protected at all time, index 0 is clearly the overall winner. The simplest algorithmic way to remove it and find the “next” winner is to move some loser (let’s say cell 30 in the diagram above) into the 0 position, and then percolate this new 0 down the tree, exchanging values, until the invariant is re-established. This is clearly logarithmic on the total number of items in the tree. By iterating over all items, you get an O(n log n) sort.

이 정렬의 멋진 기능은 삽입된 항목이 추출한 마지막 0번째 요소보다 “더 나은” 항목이 아니라면, 정렬이 진행되는 동안 새 항목을 효율적으로 삽입 할 수 있다는 것입니다. 이는 트리가 들어오는 모든 이벤트를 담고, “승리” 조건이 가장 작은 예약 시간을 의미하는 시뮬레이션 문맥에서 특히 유용합니다. 이벤트가 실행을 위해 다른 이벤트를 예약하면, 이들은 미래에 예약되어서, 쉽게 힙에 들어갈 수 있습니다. 따라서, 힙은 스케줄러를 구현하기에 좋은 구조입니다 (이것이 제가 MIDI 시퀀서에 사용한 것입니다 :-).

스케줄러를 구현하기 위한 다양한 구조가 광범위하게 연구되었으며, 힙은 합리적으로 빠르며, 속도가 거의 일정합니다, 최악의 경우는 평균 경우와 크게 다르지 않기 때문에 스케줄러에 좋습니다. 하지만, 최악의 경우는 끔찍할 수 있습니다만, 전반적으로 더 효율적인 다른 표현이 있기는 합니다.

힙은 큰 디스크 정렬에도 매우 유용합니다. 여러분은 아마도 큰 정렬은 “런(runs)”(크기가 일반적으로 CPU 메모리 크기와 관련된 사전 정렬된 시퀀스)을 생성한 후에 이러한 런들에 대한 병합 패스가 따라옴을 의미하며, 이러한 병합은 종종 매우 영리하게 조직됨을 알고 있을 겁니다 [1]. 초기 정렬이 가능한 한 가장 긴 런을 생성하는 것이 매우 중요합니다. 토너먼트는 이를 달성하기 위한 좋은 방법입니다. 토너먼트를 개최하는 데 사용할 수 있는 모든 메모리를 사용하여 현재 런에 맞는 항목들을 교체하고 침투시키면, 무작위 입력을 위한 메모리 크기의 두 배인 런을 생성하게 되고, 적당히 정렬된 입력에 대해서는 더 좋습니다.

더 나아가, 또한 디스크에 0번째 항목을 출력하고 현재 토너먼트에 맞지 않는 입력을 받으면 (그 값이 마지막 출력값을 “이기기” 때문에), 힙에 넣을 수 없어서 힙의 크기가 줄어듭니다. 해제된 메모리는 두 번째 힙을 점진적으로 구축하는데 즉시 영리하게 재사용될 수 있고, 두 번째 힙이 자라는 속도는 첫 번째 힙이 줄어드는 것과 같습니다. 첫 번째 힙이 완전히 사라지면, 힙을 전환하고 새 런을 시작합니다. 영리하고 매우 효과적입니다!

한마디로, 힙은 알아두어야 할 유용한 메모리 구조입니다. 저는 몇 가지 응용 프로그램에서 사용하며, ‘힙’ 모듈을 근처에 두는 것이 좋다고 생각합니다. :-)

각주

[1]

요즘 최신 디스크 밸런싱 알고리즘은 영리하다기보다는 성가시며, 이는 디스크의 탐색(seek) 기능으로 인한 결과입니다. 큰 테이프 드라이브와 같이 탐색할 수 없는 장치에서는, 이야기가 상당히 달랐으며, 각 테이프 움직임이 가장 효과적일 수 있도록 (즉, 병합을 “진행하는데” 최대한 참여할 수 있도록) (일찌감치) 계획하기 위해 아주 영리해야 했습니다. 일부 테이프는 반대 방향으로 읽을 수도 있었으며, 이것은 되감기 시간을 피하는 데 사용되기도 했습니다. 저를 믿으십시오, 진짜 훌륭한 테이프 정렬은 장관이었습니다! 언제나, 정렬은 항상 위대한 예술이었습니다! :-)

bisect — Array bisection algorithm

소스 코드: Lib/bisect.py [https://github.com/python/cpython/tree/main/Lib/bisect.py]

This module provides support for maintaining a list in sorted order without having to sort the list after each insertion. For long lists of items with expensive comparison operations, this can be an improvement over linear searches or frequent resorting.

The module is called bisect because it uses a basic bisection algorithm to do its work. Unlike other bisection tools that search for a specific value, the functions in this module are designed to locate an insertion point. Accordingly, the functions never call an __eq__() method to determine whether a value has been found. Instead, the functions only call the __lt__() method and will return an insertion point between values in an array.

다음과 같은 함수가 제공됩니다:

bisect.bisect_left(a, x, lo=0, hi=len(a), *, key=None)

정렬된 순서를 유지하도록 a에 x를 삽입할 위치를 찾습니다. 매개 변수 lo 와 hi는 고려해야 할 리스트의 부분집합을 지정하는 데 사용될 수 있습니다; 기본적으로 전체 리스트가 사용됩니다. x가 a에 이미 있으면, 삽입 위치는 기존 항목 앞(왼쪽)이 됩니다. 반환 값은 a가 이미 정렬되었다고 가정할 때 list.insert()의 첫 번째 매개 변수로 사용하기에 적합합니다.

The returned insertion point ip partitions the array a into two slices such that all(elem < x for elem in a[lo : ip]) is true for the left slice and all(elem >= x for elem in a[ip : hi]) is true for the right slice.

key specifies a key function of one argument that is used to extract a comparison key from each element in the array. To support searching complex records, the key function is not applied to the x value.

If key is None, the elements are compared directly and no key function is called.

버전 3.10에서 변경: Added the key parameter.

bisect.bisect_right(a, x, lo=0, hi=len(a), *, key=None)

bisect.bisect(a, x, lo=0, hi=len(a), *, key=None)

Similar to bisect_left(), but returns an insertion point which comes after (to the right of) any existing entries of x in a.

The returned insertion point ip partitions the array a into two slices such that all(elem <= x for elem in a[lo : ip]) is true for the left slice and all(elem > x for elem in a[ip : hi]) is true for the right slice.

버전 3.10에서 변경: Added the key parameter.

bisect.insort_left(a, x, lo=0, hi=len(a), *, key=None)

Insert x in a in sorted order.

This function first runs bisect_left() to locate an insertion point. Next, it runs the insert() method on a to insert x at the appropriate position to maintain sort order.

To support inserting records in a table, the key function (if any) is applied to x for the search step but not for the insertion step.

Keep in mind that the O(log n) search is dominated by the slow O(n) insertion step.

버전 3.10에서 변경: Added the key parameter.

bisect.insort_right(a, x, lo=0, hi=len(a), *, key=None)

bisect.insort(a, x, lo=0, hi=len(a), *, key=None)

Similar to insort_left(), but inserting x in a after any existing entries of x.

This function first runs bisect_right() to locate an insertion point. Next, it runs the insert() method on a to insert x at the appropriate position to maintain sort order.

To support inserting records in a table, the key function (if any) is applied to x for the search step but not for the insertion step.

Keep in mind that the O(log n) search is dominated by the slow O(n) insertion step.

버전 3.10에서 변경: Added the key parameter.

Performance Notes

When writing time sensitive code using bisect() and insort(), keep these thoughts in mind:

Bisection is effective for searching ranges of values. For locating specific values, dictionaries are more performant.

The insort() functions are O(n) because the logarithmic search step is dominated by the linear time insertion step.

The search functions are stateless and discard key function results after they are used. Consequently, if the search functions are used in a loop, the key function may be called again and again on the same array elements. If the key function isn’t fast, consider wrapping it with functools.cache() to avoid duplicate computations. Alternatively, consider searching an array of precomputed keys to locate the insertion point (as shown in the examples section below).

더 보기

Sorted Collections [https://grantjenks.com/docs/sortedcollections/] is a high performance module that uses bisect to managed sorted collections of data.

The SortedCollection recipe [https://code.activestate.com/recipes/577197-sortedcollection/] uses bisect to build a full-featured collection class with straight-forward search methods and support for a key-function. The keys are precomputed to save unnecessary calls to the key function during searches.

정렬된 리스트 검색하기

The above bisect functions are useful for finding insertion points but can be tricky or awkward to use for common searching tasks. The following five functions show how to transform them into the standard lookups for sorted lists:

def index(a, x):
    'Locate the leftmost value exactly equal to x'
    i = bisect_left(a, x)
    if i != len(a) and a[i] == x:
        return i
    raise ValueError

def find_lt(a, x):
    'Find rightmost value less than x'
    i = bisect_left(a, x)
    if i:
        return a[i-1]
    raise ValueError

def find_le(a, x):
    'Find rightmost value less than or equal to x'
    i = bisect_right(a, x)
    if i:
        return a[i-1]
    raise ValueError

def find_gt(a, x):
    'Find leftmost value greater than x'
    i = bisect_right(a, x)
    if i != len(a):
        return a[i]
    raise ValueError

def find_ge(a, x):
    'Find leftmost item greater than or equal to x'
    i = bisect_left(a, x)
    if i != len(a):
        return a[i]
    raise ValueError

Examples

The bisect() function can be useful for numeric table lookups. This example uses bisect() to look up a letter grade for an exam score (say) based on a set of ordered numeric breakpoints: 90 and up is an ‘A’, 80 to 89 is a ‘B’, and so on:

>>> def grade(score, breakpoints=[60, 70, 80, 90], grades='FDCBA'):
...     i = bisect(breakpoints, score)
...     return grades[i]
...
>>> [grade(score) for score in [33, 99, 77, 70, 89, 90, 100]]
['F', 'A', 'C', 'C', 'B', 'A', 'A']

The bisect() and insort() functions also work with lists of tuples. The key argument can serve to extract the field used for ordering records in a table:

>>> from collections import namedtuple
>>> from operator import attrgetter
>>> from bisect import bisect, insort
>>> from pprint import pprint

>>> Movie = namedtuple('Movie', ('name', 'released', 'director'))

>>> movies = [
...     Movie('Jaws', 1975, 'Spielberg'),
...     Movie('Titanic', 1997, 'Cameron'),
...     Movie('The Birds', 1963, 'Hitchcock'),
...     Movie('Aliens', 1986, 'Cameron')
... ]

>>> # Find the first movie released after 1960
>>> by_year = attrgetter('released')
>>> movies.sort(key=by_year)
>>> movies[bisect(movies, 1960, key=by_year)]
Movie(name='The Birds', released=1963, director='Hitchcock')

>>> # Insert a movie while maintaining sort order
>>> romance = Movie('Love Story', 1970, 'Hiller')
>>> insort(movies, romance, key=by_year)
>>> pprint(movies)
[Movie(name='The Birds', released=1963, director='Hitchcock'),
 Movie(name='Love Story', released=1970, director='Hiller'),
 Movie(name='Jaws', released=1975, director='Spielberg'),
 Movie(name='Aliens', released=1986, director='Cameron'),
 Movie(name='Titanic', released=1997, director='Cameron')]

If the key function is expensive, it is possible to avoid repeated function calls by searching a list of precomputed keys to find the index of a record:

>>> data = [('red', 5), ('blue', 1), ('yellow', 8), ('black', 0)]
>>> data.sort(key=lambda r: r[1])       # Or use operator.itemgetter(1).
>>> keys = [r[1] for r in data]         # Precompute a list of keys.
>>> data[bisect_left(keys, 0)]
('black', 0)
>>> data[bisect_left(keys, 1)]
('blue', 1)
>>> data[bisect_left(keys, 5)]
('red', 5)
>>> data[bisect_left(keys, 8)]
('yellow', 8)

array — Efficient arrays of numeric values

This module defines an object type which can compactly represent an array of basic values: characters, integers, floating-point numbers. Arrays are sequence types and behave very much like lists, except that the type of objects stored in them is constrained. The type is specified at object creation time by using a type code, which is a single character. The following type codes are defined:

형 코드

C 형

파이썬 형

최소 크기(바이트)

노트

'b'

signed char

int

1

'B'

unsigned char

int

1

'u'

wchar_t

유니코드 문자

2

(1)

'w'

Py_UCS4

유니코드 문자

4

'h'

signed short

int

2

'H'

unsigned short

int

2

'i'

signed int

int

2

'I'

unsigned int

int

2

'l'

signed long

int

4

'L'

unsigned long

int

4

'q'

signed long long

int

8

'Q'

unsigned long long

int

8

'f'

float

float

4

'd'

double

float

8

노트:

플랫폼에 따라 16비트 또는 32비트 일 수 있습니다.

버전 3.9에서 변경: array('u') now uses wchar_t as C type instead of deprecated Py_UNICODE. This change doesn’t affect its behavior because Py_UNICODE is alias of wchar_t since Python 3.3.

Deprecated since version 3.3, will be removed in version 3.16: Please migrate to 'w' typecode.

The actual representation of values is determined by the machine architecture (strictly speaking, by the C implementation). The actual size can be accessed through the array.itemsize attribute.

The module defines the following item:

array.typecodes

사용 가능한 모든 형 코드가 있는 문자열.

모듈은 다음 형을 정의합니다:

class array.array(typecode[, initializer])

A new array whose items are restricted by typecode, and initialized from the optional initializer value, which must be a bytes or bytearray object, a Unicode string, or iterable over elements of the appropriate type.

If given a bytes or bytearray object, the initializer is passed to the new array’s frombytes() method; if given a Unicode string, the initializer is passed to the fromunicode() method; otherwise, the initializer’s iterator is passed to the extend() method to add initial items to the array.

배열 객체는 인덱싱, 슬라이싱, 이어붙이기 및 곱셈과 같은 일반적인 시퀀스 연산을 지원합니다. 슬라이스 대입을 사용할 때, 대입되는 값은 같은 형 코드의 배열 객체여야 합니다; 다른 모든 경우에는, TypeError가 발생합니다. 배열 객체는 버퍼 인터페이스도 구현하며, 바이트열류 객체가 지원되는 곳이면 어디에서나 사용될 수 있습니다.

typecode, initializer 인자로 감사 이벤트(auditing event) array.__new__를 발생시킵니다.

typecode

배열을 만드는 데 사용된 typecode 문자.

itemsize

내부 표현에서 하나의 배열 항목의 길이 (바이트).

append(x)

배열의 끝에 값 x로 새 항목을 추가합니다.

buffer_info()

Return a tuple (address, length) giving the current memory address and the length in elements of the buffer used to hold array’s contents. The size of the memory buffer in bytes can be computed as array.buffer_info()[1] * array.itemsize. This is occasionally useful when working with low-level (and inherently unsafe) I/O interfaces that require memory addresses, such as certain ioctl() operations. The returned numbers are valid as long as the array exists and no length-changing operations are applied to it.

참고

C나 C++로 작성된 코드(이 정보를 효율적으로 사용하는 유일한 방법)에서 배열 객체를 사용할 때, 배열 객체가 지원하는 버퍼 인터페이스를 사용하는 것이 좋습니다. 이 메서드는 이전 버전과의 호환성을 위해 유지되며 새 코드에서는 사용하지 않아야 합니다. 버퍼 인터페이스는 버퍼 프로토콜에 설명되어 있습니다.

byteswap()

배열의 모든 항목을 “바이트 스와프(byteswap)” 합니다. 1, 2, 4 또는 8바이트 크기의 값에 대해서만 지원됩니다; 다른 형의 값이면 RuntimeError가 발생합니다. 바이트 순서가 다른 컴퓨터에서 작성된 파일에서 데이터를 읽을 때 유용합니다.

count(x)

배열 내에서 x가 등장하는 횟수를 반환합니다.

extend(iterable)

iterable의 항목을 배열의 끝에 추가합니다. iterable이 다른 배열이면, 정확히 같은 형 코드를 가져야 합니다; 그렇지 않으면, TypeError가 발생합니다. iterable이 배열이 아니면, 이터러블이어야 하며 요소는 배열에 추가할 올바른 형이어야 합니다.

frombytes(buffer)

Appends items from the bytes-like object, interpreting its content as an array of machine values (as if it had been read from a file using the fromfile() method).

Added in version 3.2: fromstring() is renamed to frombytes() for clarity.

fromfile(f, n)

Read n items (as machine values) from the file object f and append them to the end of the array. If less than n items are available, EOFError is raised, but the items that were available are still inserted into the array.

fromlist(list)

리스트에서 항목을 추가합니다. 이것은 형 에러가 있으면 배열이 변경되지 않는다는 점만 제외하면 for x in list: a.append(x)와 동등합니다.

fromunicode(s)

Extends this array with data from the given Unicode string. The array must have type code 'u' or 'w'; otherwise a ValueError is raised. Use array.frombytes(unicodestring.encode(enc)) to append Unicode data to an array of some other type.

index(x[, start[, stop]])

Return the smallest i such that i is the index of the first occurrence of x in the array. The optional arguments start and stop can be specified to search for x within a subsection of the array. Raise ValueError if x is not found.

버전 3.10에서 변경: Added optional start and stop parameters.

insert(i, x)

i 위치 앞에 값이 x인 새 항목을 배열에 삽입합니다. 음수 값은 배열 끝에 상대적인 값으로 처리됩니다.

pop([i])

배열에서 인덱스 i에 있는 항목을 제거하고 이를 반환합니다. 선택적 인자의 기본값은 -1이므로, 기본적으로 마지막 항목이 제거되고 반환됩니다.

remove(x)

배열에서 첫 번째 x를 제거합니다.

clear()

Remove all elements from the array.

Added in version 3.13.

reverse()

배열의 항목 순서를 뒤집습니다.

tobytes()

배열을 기곗값 배열로 변환하고 바이트열 표현(tofile() 메서드로 파일에 기록될 바이트 시퀀스와 같습니다)을 반환합니다.

Added in version 3.2: tostring() is renamed to tobytes() for clarity.

tofile(f)

모든 항목을 (기곗값으로) 파일 객체 f에 씁니다.

tolist()

배열을 같은 항목이 있는 일반 리스트로 변환합니다.

tounicode()

Convert the array to a Unicode string. The array must have a type 'u' or 'w'; otherwise a ValueError is raised. Use array.tobytes().decode(enc) to obtain a Unicode string from an array of some other type.

The string representation of array objects has the form array(typecode, initializer). The initializer is omitted if the array is empty, otherwise it is a Unicode string if the typecode is 'u' or 'w', otherwise it is a list of numbers. The string representation is guaranteed to be able to be converted back to an array with the same type and value using eval(), so long as the array class has been imported using from array import array. Variables inf and nan must also be defined if it contains corresponding floating-point values. Examples:

array('l')
array('w', 'hello \u2641')
array('l', [1, 2, 3, 4, 5])
array('d', [1.0, 2.0, 3.14, -inf, nan])

더 보기

모듈 struct

이질적인(heterogeneous) 바이너리 데이터의 패킹과 언 패킹.

NumPy [https://numpy.org/]

The NumPy package defines another array type.

weakref — 약한 참조

소스 코드: Lib/weakref.py [https://github.com/python/cpython/tree/main/Lib/weakref.py]

weakref 모듈은 파이썬 프로그래머가 객체에 대한 약한 참조 (weak references)를 만들 수 있도록 합니다.

이하에서, 용어 참조대상(referent)은 약한 참조로 참조되는 객체를 의미합니다.

객체에 대한 약한 참조만으로는 객체를 살아있게 유지할 수 없습니다: 참조대상에 대한 유일한 남은 참조가 약한 참조면, 가비지 수거는 자유롭게 참조대상을 파괴하고 메모리를 다른 용도로 재사용할 수 있습니다. 그러나 객체가 실제로 파괴될 때까지 약한 참조는 강한 참조가 없어도 객체를 반환할 수 있습니다.

약한 참조의 주요 용도는 큰 객체를 보유하는 캐시나 매핑을 구현하는 것입니다. 큰 객체는 캐시나 매핑에 등장한다는 이유만으로 살아 있지 않아야 합니다.

예를 들어, 큰 바이너리 이미지 객체가 여러 개 있을 때, 이름을 각 객체와 연관 지을 수 있습니다. 파이썬 딕셔너리를 사용하여 이름을 이미지에 매핑하거나 이미지를 이름에 매핑하면, 이미지 객체는 딕셔너리에 값이나 키로 등장하기 때문에 계속 살아있게 됩니다. weakref 모듈에서 제공하는 WeakKeyDictionary와 WeakValueDictionary 클래스는 대안이며, 약한 참조를 사용하여 매핑을 구축하기 때문에 매핑 객체에 등장한다는 이유만으로 객체를 살려두지 않습니다. 예를 들어 이미지 객체가 WeakValueDictionary 의 값이면, 해당 이미지 객체에 대한 마지막 남은 참조가 약한 매핑에 들어 있는 약한 참조이면, 가비지 수거는 객체를 회수할 수 있으며, 약한 매핑의 해당 항목은 간단히 삭제됩니다.

WeakKeyDictionary와 WeakValueDictionary는 구현에 약한 참조를 사용하여, 가비지 수거에서 키나 값이 회수될 때, 약한 딕셔너리에 알리는 약한 참조에 대한 콜백 함수를 설정합니다. WeakSet은 set 인터페이스를 구현하지만, WeakKeyDictionary 처럼 원소에 대한 약한 참조를 유지합니다.

finalize는 객체가 가비지 수거될 때 호출될 정리 함수를 등록하는 간단한 방법을 제공합니다. 이 모듈은 원시 약한 참조에 콜백 함수를 설정하는 것보다 사용하기가 더 쉽습니다. 모듈은 객체가 수거될 때까지 자동으로 파이널라이저가 활성 상태로 유지되도록 하기 때문입니다.

대부분의 프로그램은 이러한 약한 컨테이너형이나 finalize를 사용하는 것으로 충분합니다 – 일반적으로 여러분 스스로 약한 참조를 직접 만들 필요는 없습니다. 저수준 장치는 고급 용도를 위해 weakref 모듈이 노출합니다.

Not all objects can be weakly referenced. Objects which support weak references include class instances, functions written in Python (but not in C), instance methods, sets, frozensets, some file objects, generators, type objects, sockets, arrays, deques, regular expression pattern objects, and code objects.

버전 3.2에서 변경: thread.lock, threading.Lock 및 코드 객체에 대한 지원이 추가되었습니다.

list와 dict와 같은 여러 내장형은 약한 참조를 직접 지원하지 않지만, 서브 클래싱을 통해 지원을 추가할 수 있습니다:

class Dict(dict):
    pass

obj = Dict(red=1, green=2, blue=3)   # this object is weak referenceable

CPython 구현 상세: tuple과 int와 같은 다른 내장형은 서브 클래싱 될 때도 약한 참조를 지원하지 않습니다.

확장형은 쉽게 약한 참조를 지원하도록 만들 수 있습니다; 약한 참조 지원을 참조하십시오.

When __slots__ are defined for a given type, weak reference support is disabled unless a '__weakref__' string is also present in the sequence of strings in the __slots__ declaration. See __slots__ documentation for details.

class weakref.ref(object[, callback])

object에 대한 약한 참조를 반환합니다. 참조대상이 아직 살아있으면 참조 객체를 호출하여 원래 객체를 얻을 수 있습니다. 참조대상이 더는 존재하지 않으면 참조 객체를 호출할 때 None이 반환됩니다. None이 아닌 callback이 제공되고, 반환된 약한 참조 객체가 여전히 살아있으면, 객체가 파이널라이즈 되려고 할 때 콜백이 호출됩니다; 약한 참조 객체는 콜백에 유일한 매개 변수로 전달됩니다; 참조대상은 더는 사용할 수 없습니다.

같은 객체에 대해 여러 개의 약한 참조를 구성할 수 있습니다. 각 약한 참조에 등록된 콜백은 가장 최근에 등록된 콜백에서 가장 오래전에 등록된 콜백 순으로 호출됩니다.

Exceptions raised by the callback will be noted on the standard error output, but cannot be propagated; they are handled in exactly the same way as exceptions raised from an object’s __del__() method.

약한 참조는 object가 해시 가능하면 해시 가능입니다. object가 삭제된 후에도 해시값을 유지합니다. 오직 object가 삭제된 후에 hash()를 처음 호출하면, 호출은 TypeError를 발생시킵니다.

약한 참조는 동등 검사를 지원하지만, 순서는 지원하지 않습니다. 참조대상이 여전히 살아 있다면, 두 참조는 (callback과 관계없이) 참조대상과 같은 동등 관계를 갖습니다. 참조대상이 삭제되었으면, 참조 객체가 같은 객체일 때만 참조가 같습니다.

이것은 팩토리 함수가 아니라 서브 클래싱 할 수 있는 형입니다.

__callback__

이 읽기 전용 어트리뷰트는 현재 약한 참조와 연관된 콜백을 반환합니다. 콜백이 없거나 약한 참조의 참조대상이 더는 살아있지 않으면 이 어트리뷰트의 값은 None이 됩니다.

버전 3.4에서 변경: __callback__ 어트리뷰트를 추가했습니다.

weakref.proxy(object[, callback])

Return a proxy to object which uses a weak reference. This supports use of the proxy in most contexts instead of requiring the explicit dereferencing used with weak reference objects. The returned object will have a type of either ProxyType or CallableProxyType, depending on whether object is callable. Proxy objects are not hashable regardless of the referent; this avoids a number of problems related to their fundamentally mutable nature, and prevents their use as dictionary keys. callback is the same as the parameter of the same name to the ref() function.

Accessing an attribute of the proxy object after the referent is garbage collected raises ReferenceError.

버전 3.8에서 변경: 행렬 곱셈 연산자 @와 @=을 포함하도록 프락시 객체에 대한 연산자 지원을 확장했습니다.

weakref.getweakrefcount(object)

object를 참조하는 약한 참조와 프락시의 개수를 반환합니다.

weakref.getweakrefs(object)

object를 참조하는 모든 약한 참조와 프락시 객체의 리스트를 반환합니다.

class weakref.WeakKeyDictionary([dict])

키를 약하게 참조하는 매핑 클래스. 더는 키에 대한 강한 참조가 없으면 딕셔너리의 항목이 삭제됩니다. 이것은 응용 프로그램의 다른 부분이 소유한 객체에 어트리뷰트를 추가하지 않고도 추가 데이터를 연결하는 데 사용될 수 있습니다. 어트리뷰트 액세스를 재정의하는 객체에 특히 유용할 수 있습니다.

Note that when a key with equal value to an existing key (but not equal identity) is inserted into the dictionary, it replaces the value but does not replace the existing key. Due to this, when the reference to the original key is deleted, it also deletes the entry in the dictionary:

>>> class T(str): pass
...
>>> k1, k2 = T(), T()
>>> d = weakref.WeakKeyDictionary()
>>> d[k1] = 1   # d = {k1: 1}
>>> d[k2] = 2   # d = {k1: 2}
>>> del k1      # d = {}

A workaround would be to remove the key prior to reassignment:

>>> class T(str): pass
...
>>> k1, k2 = T(), T()
>>> d = weakref.WeakKeyDictionary()
>>> d[k1] = 1   # d = {k1: 1}
>>> del d[k1]
>>> d[k2] = 2   # d = {k2: 2}
>>> del k1      # d = {k2: 2}

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]에 지정된 대로, |와 |= 연산자에 대한 지원이 추가되었습니다.

WeakKeyDictionary 객체에는 내부 참조를 직접 노출하는 추가 메서드가 있습니다. 참조는 사용되는 시점에 “살아있다고” 보장되지 않아서, 참조를 호출한 결과를 사용하기 전에 확인해야 합니다. 가비지 수거기가 키를 필요 이상으로 길게 유지하도록 하는 참조를 만들지 않도록 하는 데 사용할 수 있습니다.

WeakKeyDictionary.keyrefs()

키에 대한 약한 참조의 이터러블을 반환합니다.

class weakref.WeakValueDictionary([dict])

값을 약하게 참조하는 매핑 클래스. 값에 대한 강한 참조가 더는 존재하지 않을 때 딕셔너리의 항목이 삭제됩니다.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]에 지정된 대로, |와 |= 연산자에 대한 지원이 추가되었습니다.

WeakValueDictionary objects have an additional method that has the same issues as the WeakKeyDictionary.keyrefs() method.

WeakValueDictionary.valuerefs()

값에 대한 약한 참조의 이터러블을 반환합니다.

class weakref.WeakSet([elements])

원소에 대한 약한 참조를 유지하는 집합 클래스. 원소에 대한 강한 참조가 더는 존재하지 않을 때 원소가 삭제됩니다.

class weakref.WeakMethod(method[, callback])

연결된 메서드(즉, 클래스에 정의되고 인스턴스에서 조회된 메서드)에 대한 약한 참조를 시뮬레이트 하는 사용자 지정 ref 서브 클래스. 연결된 메서드는 일시적이므로, 표준 약한 참조는 유지할 수 없습니다. WeakMethod에는 객체나 원래 함수가 죽을 때까지 연결된 메서드를 다시 만드는 특별한 코드가 있습니다:

>>> class C:
...     def method(self):
...         print("method called!")
...
>>> c = C()
>>> r = weakref.ref(c.method)
>>> r()
>>> r = weakref.WeakMethod(c.method)
>>> r()
<bound method C.method of <__main__.C object at 0x7fc859830220>>
>>> r()()
method called!
>>> del c
>>> gc.collect()
0
>>> r()
>>>

callback is the same as the parameter of the same name to the ref() function.

Added in version 3.4.

class weakref.finalize(obj, func, /, *args, **kwargs)

obj가 가비지 수거될 때 호출되는 콜러블 파이널라이저 객체를 반환합니다. 일반적인 약한 참조와 달리, 파이널라이저는 참조 객체가 수집될 때까지 항상 생존하므로, 수명 주기 관리가 크게 간소화됩니다.

파이널라이저는 (명시적으로나 가비지 수거에서) 호출될 때까지 살아있다고 간주하며, 그 후 죽습니다. 살아있는 파이널라이저를 호출하면 func(*arg, **kwargs)를 평가한 결과가 반환되고, 죽은 파이널라이저를 호출하면 None이 반환됩니다.

Exceptions raised by finalizer callbacks during garbage collection will be shown on the standard error output, but cannot be propagated. They are handled in the same way as exceptions raised from an object’s __del__() method or a weak reference’s callback.

프로그램이 종료될 때, atexit 어트리뷰트가 거짓으로 설정되지 않은 한 각 남은 살아있는 파이널라이저가 호출됩니다. 만들어진 순서와 반대 순서로 호출됩니다.

모듈 전역이 None으로 교체된 경우 인터프리터 종료의 후반 동안에는 파이널라이저가 콜백을 호출하지 않습니다.

__call__()

self가 살아 있으면 이를 죽은 것으로 표시하고 func(*args, **kwargs) 호출 결과를 반환합니다. self가 죽었으면 None을 반환합니다.

detach()

self가 살아 있으면 이를 죽은 것으로 표시하고 튜플 (obj, func, args, kwargs)를 반환합니다. self가 죽었으면 None을 반환합니다.

peek()

self가 살아 있으면 튜플 (obj, func, args, kwargs)를 반환합니다. self가 죽었으면 None을 반환합니다.

alive

파이널라이저가 살아 있으면 참이고, 그렇지 않으면 거짓인 프로퍼티.

atexit

기본값이 참인, 쓰기 가능한 불리언 프로퍼티. 프로그램이 종료할 때, atexit가 참인 남은 모든 살아있는 파이널라이저를 호출합니다. 그것들은 만들어진 순서와 반대 순서로 호출됩니다.

참고

func, args 및 kwargs가 직접이나 간접적으로 obj에 대한 참조를 소유하지 않는 것이 중요합니다. 그렇지 않으면 obj는 가비지 수거되지 않습니다. 특히, func는 obj의 연결된 메서드가 아니어야 합니다.

Added in version 3.4.

weakref.ReferenceType

약한 참조 객체의 형 객체.

weakref.ProxyType

콜러블이 아닌 객체의 프락시를 위한 형 객체.

weakref.CallableProxyType

콜러블 객체의 프락시를 위한 형 객체.

weakref.ProxyTypes

프락시의 모든 형 객체를 포함하는 시퀀스. 이것은 두 프락시 형 모두의 이름 지정에 의존하지 않고 객체가 프락시인지 검사하기 더 쉽게 만들 수 있습니다.

더 보기

PEP 205 [https://peps.python.org/pep-0205/] - 약한 참조

이전 구현에 대한 링크와 다른 언어의 유사한 기능에 대한 정보를 포함하는, 이 기능에 대한 제안과 근거.

약한 참조 객체

약한 참조 객체에는 ref.__callback__ 외에 메서드와 어트리뷰트가 없습니다. 약한 참조 객체는 참조대상이 아직 존재한다면 호출함으로써 얻을 수 있도록 합니다:

>>> import weakref
>>> class Object:
...     pass
...
>>> o = Object()
>>> r = weakref.ref(o)
>>> o2 = r()
>>> o is o2
True

참조대상이 더는 존재하지 않을 때, 참조 객체를 호출하면 None을 반환합니다:

>>> del o, o2
>>> print(r())
None

약한 참조 객체가 여전히 살아있는지를 검사하는 것은 ref() is not None 표현식을 사용하여 수행해야 합니다. 일반적으로, 참조 객체를 사용할 필요가 있는 응용 프로그램 코드는 다음 패턴을 따라야 합니다:

# r is a weak reference object
o = r()
if o is None:
    # referent has been garbage collected
    print("Object has been deallocated; can't frobnicate.")
else:
    print("Object is still live!")
    o.do_something_useful()

“생존”에 대해 별도의 검사를 사용하면 스레드 응용 프로그램에서 경쟁 조건이 발생합니다; 약한 참조가 호출되기 전에 다른 스레드가 약한 참조를 무효화 할 수 있습니다; 위에 표시된 관용구는 단일 스레드 응용 프로그램뿐만 아니라 다중 스레드 응용 프로그램에서도 안전합니다.

서브 클래싱을 통해 ref 객체의 특수한 버전을 만들 수 있습니다. 이는 WeakValueDictionary 구현에 사용되어 매핑의 각 항목에 대한 메모리 오버헤드를 줄입니다. 이는 추가 정보를 참조와 연관시키는 데 가장 유용 할 수 있지만, 참조대상을 꺼내기 위한 호출에 추가 처리를 삽입하는 데 사용될 수도 있습니다.

이 예제는 ref의 서브 클래스를 사용하여 객체에 대한 추가 정보를 저장하고 참조대상에 액세스할 때 반환되는 값에 영향을 주는 방법을 보여줍니다:

import weakref

class ExtendedRef(weakref.ref):
    def __init__(self, ob, callback=None, /, **annotations):
        super().__init__(ob, callback)
        self.__counter = 0
        for k, v in annotations.items():
            setattr(self, k, v)

    def __call__(self):
        """Return a pair containing the referent and the number of
        times the reference has been called.
        """
        ob = super().__call__()
        if ob is not None:
            self.__counter += 1
            ob = (ob, self.__counter)
        return ob

예

이 간단한 예제는 응용 프로그램이 객체 ID를 사용하여 이전에 본 객체를 조회하는 방법을 보여줍니다. 그런 다음 객체를 강제로 살아있도록 하지 않으면서 다른 자료 구조에서 객체의 ID를 사용할 수 있지만, 살아있다면 객체를 여전히 ID로 조회할 수 있습니다.

import weakref

_id2obj_dict = weakref.WeakValueDictionary()

def remember(obj):
    oid = id(obj)
    _id2obj_dict[oid] = obj
    return oid

def id2obj(oid):
    return _id2obj_dict[oid]

파이널라이저 객체

finalize를 사용해서 얻을 수 있는 주요 이점은 반환된 파이널라이저 객체를 보존할 필요 없이 콜백을 간단하게 등록할 수 있다는 것입니다. 예를 들어

>>> import weakref
>>> class Object:
...     pass
...
>>> kenny = Object()
>>> weakref.finalize(kenny, print, "You killed Kenny!")
<finalize object at ...; for 'Object' at ...>
>>> del kenny
You killed Kenny!

파이널라이저를 직접 호출할 수도 있습니다. 그러나 파이널라이저는 콜백을 최대 한 번 호출합니다.

>>> def callback(x, y, z):
...     print("CALLBACK")
...     return x + y + z
...
>>> obj = Object()
>>> f = weakref.finalize(obj, callback, 1, 2, z=3)
>>> assert f.alive
>>> assert f() == 6
CALLBACK
>>> assert not f.alive
>>> f()                     # callback not called because finalizer dead
>>> del obj                 # callback not called because finalizer dead

detach() 메서드를 사용하여 파이널라이저를 등록 취소할 수 있습니다. 그러면 파이널라이저를 죽이고 만들어질 때 생성자에 전달된 인자가 반환됩니다.

>>> obj = Object()
>>> f = weakref.finalize(obj, callback, 1, 2, z=3)
>>> f.detach()
(<...Object object ...>, <function callback ...>, (1, 2), {'z': 3})
>>> newobj, func, args, kwargs = _
>>> assert not f.alive
>>> assert newobj is obj
>>> assert func(*args, **kwargs) == 6
CALLBACK

atexit 어트리뷰트를 False로 설정하지 않는 한, 파이널라이저가 살아있다면 프로그램이 종료될 때 호출됩니다. 예를 들어

>>> obj = Object()
>>> weakref.finalize(obj, print, "obj dead or exiting")
<finalize object at ...; for 'Object' at ...>
>>> exit()
obj dead or exiting

Comparing finalizers with __del__() methods

인스턴스가 임시 디렉터리를 나타내는 클래스를 만들고 싶다고 가정하십시오. 다음 이벤트 중 첫 번째 것이 발생할 때 디렉터리는 내용과 함께 삭제되어야 합니다:

객체가 가비지 수거됩니다,

the object’s remove() method is called, or

프로그램이 종료합니다.

We might try to implement the class using a __del__() method as follows:

class TempDir:
    def __init__(self):
        self.name = tempfile.mkdtemp()

    def remove(self):
        if self.name is not None:
            shutil.rmtree(self.name)
            self.name = None

    @property
    def removed(self):
        return self.name is None

    def __del__(self):
        self.remove()

Starting with Python 3.4, __del__() methods no longer prevent reference cycles from being garbage collected, and module globals are no longer forced to None during interpreter shutdown. So this code should work without any issues on CPython.

However, handling of __del__() methods is notoriously implementation specific, since it depends on internal details of the interpreter’s garbage collector implementation.

더욱 강인한 대안은 객체의 전체 상태에 액세스하기보다 필요한 특정 함수와 객체만 참조하는 파이널라이저를 정의하는 것일 수 있습니다:

class TempDir:
    def __init__(self):
        self.name = tempfile.mkdtemp()
        self._finalizer = weakref.finalize(self, shutil.rmtree, self.name)

    def remove(self):
        self._finalizer()

    @property
    def removed(self):
        return not self._finalizer.alive

이처럼 정의된 파이널라이저는 디렉터리를 적절히 정리하는 데 필요한 세부 사항에 대한 참조만 받습니다. 객체가 가비지 수거되지 않으면 종료 시에 파이널라이저는 여전히 호출됩니다.

약한 참조 기반 파이널라이저의 다른 장점은 제삼자가 정의를 제어하는 클래스에 대해 파이널라이저를 등록하는 데 사용할 수 있다는 것입니다, 가령 모듈이 언로드 될 때 코드 실행하기:

import weakref, sys
def unloading_module():
    # implicit reference to the module globals from the function body
weakref.finalize(sys.modules[__name__], unloading_module)

참고

프로그램이 종료될 때 데몬 스레드에서 파이널라이저 객체를 만들면 종료 시에 파이널라이저가 호출되지 않을 가능성이 있습니다. 그러나, 데몬 스레드 atexit.register()에서, try: ... finally: ...와 with: ...는 정리가 발생한다고 보장하지 않습니다.

types — Dynamic type creation and names for built-in types

소스 코드: Lib/types.py [https://github.com/python/cpython/tree/main/Lib/types.py]

이 모듈은 새로운 형의 동적 생성을 지원하는 유틸리티 함수를 정의합니다.

표준 파이썬 인터프리터가 사용하지만, int나 str처럼 내장으로 노출되지 않는 일부 객체 형의 이름도 정의합니다.

마지막으로, 내장되기에 충분히 기본적이지 않은 몇 가지 추가 형 관련 유틸리티 클래스와 함수를 제공합니다.

동적 형 생성

types.new_class(name, bases=(), kwds=None, exec_body=None)

적절한 메타 클래스를 사용하여 동적으로 클래스 객체를 만듭니다.

처음 세 개의 인자는 클래스 정의 헤더를 구성하는 요소들입니다: 클래스 이름, 베이스 클래스 (순서대로), 키워드 인자 (가령 metaclass).

The exec_body argument is a callback that is used to populate the freshly created class namespace. It should accept the class namespace as its sole argument and update the namespace directly with the class contents. If no callback is provided, it has the same effect as passing in lambda ns: None.

Added in version 3.3.

types.prepare_class(name, bases=(), kwds=None)

적절한 메타 클래스를 계산하고 클래스 이름 공간을 만듭니다.

인자는 클래스 정의 헤더를 구성하는 요소들입니다: 클래스 이름, 베이스 클래스 (순서대로) 및 키워드 인자 (가령 metaclass).

반환 값은 3-튜플입니다: metaclass, namespace, kwds

metaclass는 적절한 메타 클래스이고, namespace는 준비된 클래스 이름 공간이며 kwds는 'metaclass' 항목이 제거된 전달된 kwds 인자의 갱신된 사본입니다. kwds 인자가 전달되지 않으면, 빈 딕셔너리가 됩니다.

Added in version 3.3.

버전 3.6에서 변경: 반환된 튜플의 namespace 요소의 기본값이 변경되었습니다. 이제 메타 클래스에 __prepare__ 메서드가 없으면 삽입 순서 보존 맵핑이 사용됩니다.

더 보기

메타 클래스

이 함수들이 지원하는 클래스 생성 절차에 대한 자세한 내용

PEP 3115 [https://peps.python.org/pep-3115/] - 파이썬 3000의 메타 클래스

__prepare__ 이름 공간 훅을 도입했습니다

types.resolve_bases(bases)

PEP 560 [https://peps.python.org/pep-0560/]의 명세에 따라 MRO 항목을 동적으로 결정합니다.

This function looks for items in bases that are not instances of type, and returns a tuple where each such object that has an __mro_entries__() method is replaced with an unpacked result of calling this method. If a bases item is an instance of type, or it doesn’t have an __mro_entries__() method, then it is included in the return tuple unchanged.

Added in version 3.7.

types.get_original_bases(cls, /)

Return the tuple of objects originally given as the bases of cls before the __mro_entries__() method has been called on any bases (following the mechanisms laid out in PEP 560 [https://peps.python.org/pep-0560/]). This is useful for introspecting Generics.

For classes that have an __orig_bases__ attribute, this function returns the value of cls.__orig_bases__. For classes without the __orig_bases__ attribute, cls.__bases__ is returned.

Examples:

from typing import TypeVar, Generic, NamedTuple, TypedDict

T = TypeVar("T")
class Foo(Generic[T]): ...
class Bar(Foo[int], float): ...
class Baz(list[str]): ...
Eggs = NamedTuple("Eggs", [("a", int), ("b", str)])
Spam = TypedDict("Spam", {"a": int, "b": str})

assert Bar.__bases__ == (Foo, float)
assert get_original_bases(Bar) == (Foo[int], float)

assert Baz.__bases__ == (list,)
assert get_original_bases(Baz) == (list[str],)

assert Eggs.__bases__ == (tuple,)
assert get_original_bases(Eggs) == (NamedTuple,)

assert Spam.__bases__ == (dict,)
assert get_original_bases(Spam) == (TypedDict,)

assert int.__bases__ == (object,)
assert get_original_bases(int) == (object,)

Added in version 3.12.

더 보기

PEP 560 [https://peps.python.org/pep-0560/] - typing 모듈과 제네릭 형에 대한 코어 지원

표준 인터프리터 형

이 모듈은 파이썬 인터프리터를 구현하는 데 필요한 많은 형의 이름을 제공합니다. listiterator 형과 같이 처리 중에 우연히 발생하는 일부 형은 의도적으로 포함하지 않았습니다.

이러한 이름의 일반적인 용도는 isinstance()나 issubclass() 검사입니다.

이러한 형을 인스턴스 화할 때는 서명이 파이썬 버전마다 다를 수 있음에 유의해야 합니다.

다음과 같은 형들에 대해 표준 이름이 정의됩니다:

types.NoneType

The type of None.

Added in version 3.10.

types.FunctionType

types.LambdaType

사용자 정의 함수와 lambda 표현식이 만든 함수의 형.

인자 code로 감사 이벤트 function.__new__를 발생시킵니다.

감사 이벤트는 함수 객체의 직접 인스턴스 화에서만 발생하며, 일반 컴파일에서는 발생하지 않습니다.

types.GeneratorType

제너레이터 함수가 만든, 제너레이터-이터레이터 객체의 형.

types.CoroutineType

async def 함수가 만든 코루틴 객체의 형.

Added in version 3.5.

types.AsyncGeneratorType

비동기 제너레이터 함수가 만든, 비동기 제너레이터-이터레이터 객체의 형.

Added in version 3.6.

class types.CodeType(**kwargs)

The type of code objects such as returned by compile().

인자 code, filename, name, argcount, posonlyargcount, kwonlyargcount, nlocals, stacksize, flags로 감사 이벤트 code.__new__를 발생시킵니다.

감사된 인자는 초기화자가 요구하는 이름이나 위치와 일치하지 않을 수 있음에 유의하십시오. 감사 이벤트는 코드 객체의 직접 인스턴스 화에서만 발생하며, 일반 컴파일에서는 발생하지 않습니다.

types.CellType

The type for cell objects: such objects are used as containers for a function’s closure variables.

Added in version 3.8.

types.MethodType

사용자 정의 클래스 인스턴스의 메서드 형.

types.BuiltinFunctionType

types.BuiltinMethodType

len()이나 sys.exit() 와 같은 내장 함수와 내장 클래스의 메서드의 형. (여기서, “내장”이라는 용어는 “C로 작성된”을 의미합니다.)

types.WrapperDescriptorType

object.__init__()나 object.__lt__()와 같은, 일부 내장 데이터형과 베이스 클래스의 메서드의 형.

Added in version 3.7.

types.MethodWrapperType

일부 내장 데이터형과 베이스 클래스의 연결된(bound) 메서드의 형. 예를 들어 object().__str__의 형입니다.

Added in version 3.7.

types.NotImplementedType

The type of NotImplemented.

Added in version 3.10.

types.MethodDescriptorType

str.join()과 같은 일부 내장 데이터형의 메서드의 형.

Added in version 3.7.

types.ClassMethodDescriptorType

dict.__dict__['fromkeys']와 같은 일부 내장 데이터형의 연결되지 않은(unbound) 클래스 메서드의 형.

Added in version 3.7.

class types.ModuleType(name, doc=None)

모듈의 형. 생성자는 만들 모듈의 이름과 선택적으로 독스트링을 취합니다.

더 보기

Documentation on module objects

Provides details on the special attributes that can be found on instances of ModuleType.

importlib.util.module_from_spec()

Modules created using the ModuleType constructor are created with many of their special attributes unset or set to default values. module_from_spec() provides a more robust way of creating ModuleType instances which ensures the various attributes are set appropriately.

types.EllipsisType

The type of Ellipsis.

Added in version 3.10.

class types.GenericAlias(t_origin, t_args)

list[int]와 같은 매개 변수화된 제네릭의 형입니다.

t_origin은 list, tuple 또는 dict와 같이 매개 변수화되지 않은 제네릭 클래스여야 합니다. t_args는 t_origin을 매개 변수화하는 형의 tuple(길이 1일 수 있습니다)이어야 합니다:

>>> from types import GenericAlias

>>> list[int] == GenericAlias(list, (int,))
True
>>> dict[str, int] == GenericAlias(dict, (str, int))
True

Added in version 3.9.

버전 3.9.2에서 변경: 이 형은 이제 서브 클래싱 할 수 있습니다.

더 보기

Generic Alias Types

In-depth documentation on instances of types.GenericAlias

PEP 585 [https://peps.python.org/pep-0585/] - Type Hinting Generics In Standard Collections

Introducing the types.GenericAlias class

class types.UnionType

The type of union type expressions.

Added in version 3.10.

class types.TracebackType(tb_next, tb_frame, tb_lasti, tb_lineno)

The type of traceback objects such as found in sys.exception().__traceback__.

사용 가능한 어트리뷰트와 연산에 대한 세부 사항 및 동적으로 트레이스백을 만드는 것에 대한 지침은 언어 레퍼런스를 참조하십시오.

types.FrameType

The type of frame objects such as found in tb.tb_frame if tb is a traceback object.

types.GetSetDescriptorType

The type of objects defined in extension modules with PyGetSetDef, such as FrameType.f_locals or array.array.typecode. This type is used as descriptor for object attributes; it has the same purpose as the property type, but for classes defined in extension modules.

types.MemberDescriptorType

datetime.timedelta.days와 같은, PyMemberDef가 있는 확장 모듈에서 정의된 객체의 형. 이 형은 표준 변환 함수를 사용하는 간단한 C 데이터 멤버의 디스크립터로 사용됩니다; property 형과 같은 목적을 갖지만, 확장 모듈에 정의된 클래스를 위한 것입니다.

In addition, when a class is defined with a __slots__ attribute, then for each slot, an instance of MemberDescriptorType will be added as an attribute on the class. This allows the slot to appear in the class’s __dict__.

CPython 구현 상세: 파이썬의 다른 구현에서, 이 형은 GetSetDescriptorType과 같을 수 있습니다.

class types.MappingProxyType(mapping)

매핑의 읽기 전용 프락시. 매핑 항목에 대한 동적 뷰를 제공하는데, 매핑이 변경될 때 뷰가 이러한 변경 사항을 반영함을 의미합니다.

Added in version 3.3.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]의 새 병합 (|) 연산자를 지원하도록 갱신되었습니다. 단순히 하부 매핑에 위임합니다.

key in proxy

하부 매핑에 키 key가 있으면 True를, 그렇지 않으면 False를 반환합니다.

proxy[key]

키 key를 사용하여 하부 매핑의 항목을 반환합니다. key가 하부 매핑에 없으면 KeyError를 발생시킵니다.

iter(proxy)

하부 매핑의 키에 대한 이터레이터를 반환합니다. 이것은 iter(proxy.keys())의 줄임 표현입니다.

len(proxy)

하부 매핑의 항목 수를 반환합니다.

copy()

하부 매핑의 얕은 사본을 반환합니다.

get(key[, default])

key가 하부 매핑에 있으면 key의 값을, 그렇지 않으면 default를 반환합니다. default를 지정하지 않으면, 기본적으로 None으로 설정되므로, 이 메서드는 절대 KeyError를 발생시키지 않습니다.

items()

하부 매핑의 항목(items)((key, value) 쌍)의 새 뷰를 반환합니다.

keys()

하부 매핑의 키(keys)의 새로운 뷰를 반환합니다.

values()

하부 매핑의 값(values)의 새 뷰를 반환합니다.

reversed(proxy)

하부 매핑의 키(keys)에 대한 역 이터레이터를 반환합니다.

Added in version 3.9.

hash(proxy)

Return a hash of the underlying mapping.

Added in version 3.12.

class types.CapsuleType

The type of capsule objects.

Added in version 3.13.

추가 유틸리티 클래스와 함수

class types.SimpleNamespace

이름 공간에 대한 어트리뷰트 액세스와 의미 있는 repr을 제공하는 간단한 object 서브 클래스.

Unlike object, with SimpleNamespace you can add and remove attributes.

SimpleNamespace objects may be initialized in the same way as dict: either with keyword arguments, with a single positional argument, or with both. When initialized with keyword arguments, those are directly added to the underlying namespace. Alternatively, when initialized with a positional argument, the underlying namespace will be updated with key-value pairs from that argument (either a mapping object or an iterable object producing key-value pairs). All such keys must be strings.

형은 다음 코드와 대략 동등합니다:

class SimpleNamespace:
    def __init__(self, mapping_or_iterable=(), /, **kwargs):
        self.__dict__.update(mapping_or_iterable)
        self.__dict__.update(kwargs)

    def __repr__(self):
        items = (f"{k}={v!r}" for k, v in self.__dict__.items())
        return "{}({})".format(type(self).__name__, ", ".join(items))

    def __eq__(self, other):
        if isinstance(self, SimpleNamespace) and isinstance(other, SimpleNamespace):
           return self.__dict__ == other.__dict__
        return NotImplemented

SimpleNamespace는 class NS: pass의 대체품으로 유용할 수 있습니다. 하지만, 구조화된 레코드형에는 namedtuple()을 대신 사용하십시오.

SimpleNamespace objects are supported by copy.replace().

Added in version 3.3.

버전 3.9에서 변경: repr의 어트리뷰트 순서가 알파벳순에서 삽입 순으로 변경되었습니다 (dict처럼).

버전 3.13에서 변경: Added support for an optional positional argument.

types.DynamicClassAttribute(fget=None, fset=None, fdel=None, doc=None)

클래스의 어트리뷰트 액세스를 __getattr__ 로 보냅니다.

디스크립터이며, 인스턴스와 클래스를 통해 액세스할 때 다르게 작동하는 어트리뷰트를 정의하는 데 사용됩니다. 인스턴스 액세스는 정상적으로 유지되지만, 클래스를 통한 어트리뷰트 액세스는 클래스의 __getattr__ 메서드로 보냅니다; 이는 AttributeError를 발생 시켜 수행됩니다.

이를 통해 인스턴스에서 활성화된 프로퍼티를 가짐과 동시에, 클래스에서 같은 이름을 가진 가상 어트리뷰트를 가질 수 있습니다 (예제는 enum.Enum을 참조하십시오).

Added in version 3.4.

코루틴 유틸리티 함수

types.coroutine(gen_func)

This function transforms a generator function into a coroutine function which returns a generator-based coroutine. The generator-based coroutine is still a generator iterator, but is also considered to be a coroutine object and is awaitable. However, it may not necessarily implement the __await__() method.

gen_func가 제너레이터 함수면 제자리(in-place)에서 수정됩니다.

gen_func가 제너레이터 함수가 아니면, 래핑 됩니다. collections.abc.Generator의 인스턴스를 반환하면, 인스턴스는 어웨이터블 프락시 객체로 래핑 됩니다. 다른 모든 형의 객체는 그대로 반환됩니다.

Added in version 3.5.

copy — Shallow and deep copy operations

소스 코드: Lib/copy.py [https://github.com/python/cpython/tree/main/Lib/copy.py]

파이썬에서 대입문은 객체를 복사하지 않고, 대상과 객체 사이에 바인딩을 만듭니다.가변(mutable) 컬렉션 또는 가변(mutable) 항목들을 포함한 컬렉션의 경우때로 컬렉션을 변경하지 않고 사본을 변경하기 위해 복사가 필요합니다.이 모듈은 일반적인 얕은 복사와 깊은 복사 연산을 제공합니다. (아래 설명 참고)

인터페이스 요약:

copy.copy(obj)

Return a shallow copy of obj.

copy.deepcopy(obj[, memo])

Return a deep copy of obj.

copy.replace(obj, /, **changes)

Creates a new object of the same type as obj, replacing fields with values from changes.

Added in version 3.13.

exception copy.Error

모듈 특정 에러의 경우 발생됩니다.

얕은 복사와 깊은 복사의 차이점은복합 객체(리스트 또는 클래스 인스턴스들과 같은 다른 객체를 포함한 객체)에만 유효합니다.

얕은 복사는 새로운 복합 객체를 만들고,(가능한 범위까지) 원본 객체를 가리키는 참조를 새로운 복합 객체에 삽입합니다.

깊은 복사는 새로운 복합 객체를 만들고,재귀적으로 원본 객체의 사본을 새로 만든 복합 객체에 삽입합니다.

깊은 복사 연산은 얕은 복사 연산에는 없는 두 가지 문제가 있습니다:

재귀 객체(직접적 또는 간접적으로 자신에 대한 참조를 포함하는 복합 객체)는 순환 루프의 원인이 될 수 있습니다.

깊은 복사는 모든 것을 복사하기 때문에, 지나치게 많이 복사할 수 있습니다. 가령, 복사본 간에 공유할 의도가 있는 것까지도.

deepcopy() 함수는 다음과 같은 방법으로 이 문제들을 피합니다:

현재 복사 패스 중에 이미 복사된 객체의 memo 딕셔너리를 가지고 있습니다; 그리고

사용자 정의 클래스가 복사 연산 또는 복사된 구성요소 집합을 재정의하도록 합니다.

This module does not copy types like module, method, stack trace, stack frame, file, socket, window, or any similar types. It does “copy” functions and classes (shallow and deeply), by returning the original object unchanged; this is compatible with the way these are treated by the pickle module.

딕셔너리의 얕은 복사는 dict.copy()를 사용하여 복사할 수 있습니다.그리고 리스트의 얕은 복사는 예를 들어 copied_list = original_list[:] 처럼전체 리스트의 슬라이스를 대입하여 리스트를 복사할 수도 있습니다.

클래스는 피클링을 제어하기 위해 사용하는 것과 같은 인터페이스를 사용하여 복사를 제어할 수 있습니다.이러한 메서드들의 정보는 pickle 모듈 설명을 참고하세요.실제로 copy 모듈은 copyreg 모듈에 등록된 피클 함수를 사용합니다.

In order for a class to define its own copy implementation, it can define special methods __copy__() and __deepcopy__().

object.__copy__(self)

Called to implement the shallow copy operation; no additional arguments are passed.

object.__deepcopy__(self, memo)

Called to implement the deep copy operation; it is passed one argument, the memo dictionary. If the __deepcopy__ implementation needs to make a deep copy of a component, it should call the deepcopy() function with the component as first argument and the memo dictionary as second argument. The memo dictionary should be treated as an opaque object.

Function copy.replace() is more limited than copy() and deepcopy(), and only supports named tuples created by namedtuple(), dataclasses, and other classes which define method __replace__().

object.__replace__(self, /, **changes)

This method should create a new object of the same type, replacing fields with values from changes.

더 보기

모듈 pickle

객체 상태 조회와 복원을 지원하는데 사용되는 특수 메서드에 관한 논의

pprint — Data pretty printer

소스 코드: Lib/pprint.py [https://github.com/python/cpython/tree/main/Lib/pprint.py]

pprint 모듈은 임의의 파이썬 데이터 구조를 인터프리터의 입력으로 사용할 수 있는 형태로 “예쁘게 인쇄”할 수 있는 기능을 제공합니다. 포맷된 구조에 기본 파이썬 형이 아닌 객체가 포함되면, 표현은 로드되지 않을 수 있습니다. 파일, 소켓 또는 클래스와 같은 객체뿐만 아니라 파이썬 리터럴로 표현할 수 없는 다른 많은 객체가 포함된 경우입니다.

The formatted representation keeps objects on a single line if it can, and breaks them onto multiple lines if they don’t fit within the allowed width, adjustable by the width parameter defaulting to 80 characters.

딕셔너리는 디스플레이를 계산하기 전에 키로 정렬됩니다.

버전 3.9에서 변경: types.SimpleNamespace를 예쁘게 인쇄하는 지원이 추가되었습니다.

버전 3.10에서 변경: Added support for pretty-printing dataclasses.dataclass.

Functions

pprint.pp(object, stream=None, indent=1, width=80, depth=None, *, compact=False, sort_dicts=False, underscore_numbers=False)

Prints the formatted representation of object, followed by a newline. This function may be used in the interactive interpreter instead of the print() function for inspecting values. Tip: you can reassign print = pprint.pp for use within a scope.

매개변수:

object – The object to be printed.

stream (file-like object | None) – A file-like object to which the output will be written by calling its write() method. If None (the default), sys.stdout is used.

indent (int) – The amount of indentation added for each nesting level.

width (int) – The desired maximum number of characters per line in the output. If a structure cannot be formatted within the width constraint, a best effort will be made.

depth (int | None) – The number of nesting levels which may be printed. If the data structure being printed is too deep, the next contained level is replaced by .... If None (the default), there is no constraint on the depth of the objects being formatted.

compact (bool) – Control the way long sequences are formatted. If False (the default), each item of a sequence will be formatted on a separate line, otherwise as many items as will fit within the width will be formatted on each output line.

sort_dicts (bool) – If True, dictionaries will be formatted with their keys sorted, otherwise they will be displayed in insertion order (the default).

underscore_numbers (bool) – If True, integers will be formatted with the _ character for a thousands separator, otherwise underscores are not displayed (the default).

>>> import pprint
>>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
>>> stuff.insert(0, stuff)
>>> pprint.pp(stuff)
[<Recursion on list with id=...>,
 'spam',
 'eggs',
 'lumberjack',
 'knights',
 'ni']

Added in version 3.8.

pprint.pprint(object, stream=None, indent=1, width=80, depth=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Alias for pp() with sort_dicts set to True by default, which would automatically sort the dictionaries’ keys, you might want to use pp() instead where it is False by default.

pprint.pformat(object, indent=1, width=80, depth=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Return the formatted representation of object as a string. indent, width, depth, compact, sort_dicts and underscore_numbers are passed to the PrettyPrinter constructor as formatting parameters and their meanings are as described in the documentation above.

pprint.isreadable(object)

object의 포맷된 표현이 “읽을 수 있는”지, 즉 eval()을 사용하여 값을 재구성하는 데 사용할 수 있는지 판단합니다. 재귀적 객체에 대해서는 항상 False를 반환합니다.

>>> pprint.isreadable(stuff)
False

pprint.isrecursive(object)

Determine if object requires a recursive representation. This function is subject to the same limitations as noted in saferepr() below and may raise an RecursionError if it fails to detect a recursive object.

pprint.saferepr(object)

Return a string representation of object, protected against recursion in some common data structures, namely instances of dict, list and tuple or subclasses whose __repr__ has not been overridden. If the representation of object exposes a recursive entry, the recursive reference will be represented as <Recursion on typename with id=number>. The representation is not otherwise formatted.

>>> pprint.saferepr(stuff)
"[<Recursion on list with id=...>, 'spam', 'eggs', 'lumberjack', 'knights', 'ni']"

PrettyPrinter 객체

class pprint.PrettyPrinter(indent=1, width=80, depth=None, stream=None, *, compact=False, sort_dicts=True, underscore_numbers=False)

Construct a PrettyPrinter instance.

Arguments have the same meaning as for pp(). Note that they are in a different order, and that sort_dicts defaults to True.

>>> import pprint
>>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
>>> stuff.insert(0, stuff[:])
>>> pp = pprint.PrettyPrinter(indent=4)
>>> pp.pprint(stuff)
[   ['spam', 'eggs', 'lumberjack', 'knights', 'ni'],
    'spam',
    'eggs',
    'lumberjack',
    'knights',
    'ni']
>>> pp = pprint.PrettyPrinter(width=41, compact=True)
>>> pp.pprint(stuff)
[['spam', 'eggs', 'lumberjack',
  'knights', 'ni'],
 'spam', 'eggs', 'lumberjack', 'knights',
 'ni']
>>> tup = ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead',
... ('parrot', ('fresh fruit',))))))))
>>> pp = pprint.PrettyPrinter(depth=6)
>>> pp.pprint(tup)
('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead', (...)))))))

버전 3.4에서 변경: compact 매개 변수가 추가되었습니다.

버전 3.8에서 변경: sort_dicts 매개 변수가 추가되었습니다.

버전 3.10에서 변경: Added the underscore_numbers parameter.

버전 3.11에서 변경: No longer attempts to write to sys.stdout if it is None.

PrettyPrinter 인스턴스에는 다음과 같은 메서드가 있습니다:

PrettyPrinter.pformat(object)

object의 포맷된 표현을 반환합니다. PrettyPrinter 생성자에 전달된 옵션을 고려합니다.

PrettyPrinter.pprint(object)

구성된 스트림에 object의 포맷된 표현과 불 넘김을 인쇄합니다.

다음 메서드는 같은 이름의 해당 함수에 대한 구현을 제공합니다. 새로운 PrettyPrinter 객체를 만들 필요가 없으므로, 인스턴스에서 이러한 메서드를 사용하는 것이 약간 더 효율적입니다.

PrettyPrinter.isreadable(object)

object의 포맷된 표현이 “읽을 수 있는”지, 즉 eval()을 사용하여 값을 재구성하는 데 사용할 수 있는지 판단합니다. 재귀 객체에 대해 False를 반환함에 유의하십시오. PrettyPrinter의 depth 매개 변수가 설정되고 객체가 허용된 것보다 더 깊으면, False를 반환합니다.

PrettyPrinter.isrecursive(object)

object가 재귀적 표현을 요구하는지 판단합니다.

이 메서드는 서브 클래스가 객체가 문자열로 변환되는 방식을 수정할 수 있도록 하는 훅으로 제공됩니다. 기본 구현은 saferepr() 구현의 내부를 사용합니다.

PrettyPrinter.format(object, context, maxlevels, level)

세 가지 값을 반환합니다: 포맷된 버전의 object를 문자열로, 결과가 읽을 수 있는지를 나타내는 플래그와 재귀가 감지되었는지를 나타내는 플래그. 첫 번째 인자는 표시할 객체입니다. 두 번째는 현재 표현 컨텍스트(표현에 영향을 주는 object의 직접 및 간접 컨테이너)의 일부인 객체의 id()를 키로 포함하는 딕셔너리입니다; 이미 context에 표현된 객체가 표현되어야 할 필요가 있으면, 세 번째 반환 값은 True이어야 합니다. format() 메서드에 대한 재귀 호출은 컨테이너에 대한 추가 항목을 이 딕셔너리에 추가해야 합니다. 세 번째 인자 maxlevels는 재귀에 요청된 제한을 줍니다; 요청된 제한이 없으면 0입니다. 이 인자는 재귀 호출에 수정되지 않은 채 전달되어야 합니다. 네 번째 인자 level은 현재 수준을 제공합니다; 재귀 호출은 현재 호출보다 작은 값으로 전달되어야 합니다.

예제

To demonstrate several uses of the pp() function and its parameters, let’s fetch information about a project from PyPI [https://pypi.org]:

>>> import json
>>> import pprint
>>> from urllib.request import urlopen
>>> with urlopen('https://pypi.org/pypi/sampleproject/1.2.0/json') as resp:
...     project_info = json.load(resp)['info']

In its basic form, pp() shows the whole object:

>>> pprint.pp(project_info)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': ['Development Status :: 3 - Alpha',
                 'Intended Audience :: Developers',
                 'License :: OSI Approved :: MIT License',
                 'Programming Language :: Python :: 2',
                 'Programming Language :: Python :: 2.6',
                 'Programming Language :: Python :: 2.7',
                 'Programming Language :: Python :: 3',
                 'Programming Language :: Python :: 3.2',
                 'Programming Language :: Python :: 3.3',
                 'Programming Language :: Python :: 3.4',
                 'Topic :: Software Development :: Build Tools'],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the project.\n'
                '\n'
                'The file should use UTF-8 encoding and be written using '
                'ReStructured Text. It\n'
                'will be used to generate the project webpage on PyPI, and '
                'should be written for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would include an overview of '
                'the project, basic\n'
                'usage examples, etc. Generally, including the project '
                'changelog in here is not\n'
                'a good idea, although a simple "What\'s New" section for the '
                'most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {'last_day': -1, 'last_month': -1, 'last_week': -1},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {'Download': 'UNKNOWN',
                  'Homepage': 'https://github.com/pypa/sampleproject'},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}

결과는 특정 depth로 제한될 수 있습니다 (더 깊은 내용에는 줄임표가 사용됩니다):

>>> pprint.pp(project_info, depth=1)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': [...],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the project.\n'
                '\n'
                'The file should use UTF-8 encoding and be written using '
                'ReStructured Text. It\n'
                'will be used to generate the project webpage on PyPI, and '
                'should be written for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would include an overview of '
                'the project, basic\n'
                'usage examples, etc. Generally, including the project '
                'changelog in here is not\n'
                'a good idea, although a simple "What\'s New" section for the '
                'most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {...},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {...},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}

또한, 최대 문자 width를 제안할 수 있습니다. 긴 객체를 분할 할 수 없으면, 지정된 너비를 초과합니다:

>>> pprint.pp(project_info, depth=1, width=60)
{'author': 'The Python Packaging Authority',
 'author_email': 'pypa-dev@googlegroups.com',
 'bugtrack_url': None,
 'classifiers': [...],
 'description': 'A sample Python project\n'
                '=======================\n'
                '\n'
                'This is the description file for the '
                'project.\n'
                '\n'
                'The file should use UTF-8 encoding and be '
                'written using ReStructured Text. It\n'
                'will be used to generate the project '
                'webpage on PyPI, and should be written '
                'for\n'
                'that purpose.\n'
                '\n'
                'Typical contents for this file would '
                'include an overview of the project, '
                'basic\n'
                'usage examples, etc. Generally, including '
                'the project changelog in here is not\n'
                'a good idea, although a simple "What\'s '
                'New" section for the most recent version\n'
                'may be appropriate.',
 'description_content_type': None,
 'docs_url': None,
 'download_url': 'UNKNOWN',
 'downloads': {...},
 'home_page': 'https://github.com/pypa/sampleproject',
 'keywords': 'sample setuptools development',
 'license': 'MIT',
 'maintainer': None,
 'maintainer_email': None,
 'name': 'sampleproject',
 'package_url': 'https://pypi.org/project/sampleproject/',
 'platform': 'UNKNOWN',
 'project_url': 'https://pypi.org/project/sampleproject/',
 'project_urls': {...},
 'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
 'requires_dist': None,
 'requires_python': None,
 'summary': 'A sample Python project',
 'version': '1.2.0'}

reprlib — Alternate repr() implementation

소스 코드: Lib/reprlib.py [https://github.com/python/cpython/tree/main/Lib/reprlib.py]

The reprlib module provides a means for producing object representations with limits on the size of the resulting strings. This is used in the Python debugger and may be useful in other contexts as well.

이 모듈은 클래스, 인스턴스 및 함수를 제공합니다.:

class reprlib.Repr(*, maxlevel=6, maxtuple=6, maxlist=6, maxarray=5, maxdict=4, maxset=6, maxfrozenset=6, maxdeque=6, maxstring=30, maxlong=40, maxother=30, fillvalue='...', indent=None)

내장 repr()과 유사한 함수를 구현하는 데 유용한 포매팅 서비스를 제공하는 클래스; 과도하게 긴 표현의 생성을 피하고자 객체 형별로 크기 제한이 추가됩니다.

The keyword arguments of the constructor can be used as a shortcut to set the attributes of the Repr instance. Which means that the following initialization:

aRepr = reprlib.Repr(maxlevel=3)

Is equivalent to:

aRepr = reprlib.Repr()
aRepr.maxlevel = 3

See section Repr Objects for more information about Repr attributes.

버전 3.12에서 변경: Allow attributes to be set via keyword arguments.

reprlib.aRepr

아래에 설명된 repr()로 함수를 제공하는 데 사용되는 Repr의 인스턴스입니다. 이 객체의 어트리뷰트를 변경하면 repr()과 파이썬 디버거에서 사용되는 크기 제한에 영향을 줍니다.

reprlib.repr(obj)

aRepr의 repr() 메서드입니다. 같은 이름의 내장 함수에 의해 반환된 것과 비슷한 문자열을 반환하지만, 대부분의 크기에는 제한이 있습니다.

In addition to size-limiting tools, the module also provides a decorator for detecting recursive calls to __repr__() and substituting a placeholder string instead.

@reprlib.recursive_repr(fillvalue='...')

Decorator for __repr__() methods to detect recursive calls within the same thread. If a recursive call is made, the fillvalue is returned, otherwise, the usual __repr__() call is made. For example:

>>> from reprlib import recursive_repr
>>> class MyList(list):
...     @recursive_repr()
...     def __repr__(self):
...         return '<' + '|'.join(map(repr, self)) + '>'
...
>>> m = MyList('abc')
>>> m.append(m)
>>> m.append('x')
>>> print(m)
<'a'|'b'|'c'|...|'x'>

Added in version 3.2.

Repr 객체

Repr 인스턴스는 여러 객체 형의 표현에 대한 크기 제한과 특정 객체 형을 포맷하는 메서드를 제공하는데 사용될 수 있습니다.

Repr.fillvalue

This string is displayed for recursive references. It defaults to ....

Added in version 3.11.

Repr.maxlevel

재귀적 표현의 생성에 대한 심도 한계. 기본값은 6입니다.

Repr.maxdict

Repr.maxlist

Repr.maxtuple

Repr.maxset

Repr.maxfrozenset

Repr.maxdeque

Repr.maxarray

명명된 객체 형을 표현하는 항목 수 제한. 기본값은 maxdict은 4, maxarray는 5 이고 그 외는 6입니다.

Repr.maxlong

정수 표현의 최대 문자 수입니다. 숫자는 가운데에서 삭제됩니다. 기본값은 40입니다.

Repr.maxstring

문자열 표현의 문자 수 제한. 문자열의 “통상” 표현이 문자 소스로써 사용되는 것에 주의해 주세요: 표현에 이스케이프 시퀀스가 필요하면, 표현이 짧아질 때 이것이 망가질 수 있습니다. 기본값은 30입니다.

Repr.maxother

이 제한은 Repr 객체에서 구체적인 포맷 메서드를 사용할 수 없는 객체 형의 크기를 제어하는 데 사용됩니다. maxstring과 비슷한 방식으로 적용됩니다. 기본값은 20입니다.

Repr.indent

If this attribute is set to None (the default), the output is formatted with no line breaks or indentation, like the standard repr(). For example:

>>> example = [
...     1, 'spam', {'a': 2, 'b': 'spam eggs', 'c': {3: 4.5, 6: []}}, 'ham']
>>> import reprlib
>>> aRepr = reprlib.Repr()
>>> print(aRepr.repr(example))
[1, 'spam', {'a': 2, 'b': 'spam eggs', 'c': {3: 4.5, 6: []}}, 'ham']

If indent is set to a string, each recursion level is placed on its own line, indented by that string:

>>> aRepr.indent = '-->'
>>> print(aRepr.repr(example))
[
-->1,
-->'spam',
-->{
-->-->'a': 2,
-->-->'b': 'spam eggs',
-->-->'c': {
-->-->-->3: 4.5,
-->-->-->6: [],
-->-->},
-->},
-->'ham',
]

Setting indent to a positive integer value behaves as if it was set to a string with that number of spaces:

>>> aRepr.indent = 4
>>> print(aRepr.repr(example))
[
    1,
    'spam',
    {
        'a': 2,
        'b': 'spam eggs',
        'c': {
            3: 4.5,
            6: [],
        },
    },
    'ham',
]

Added in version 3.12.

Repr.repr(obj)

인스턴스에 의해 부과된 포매팅을 사용하는 내장 repr()와 등등합니다.

Repr.repr1(obj, level)

repr()에서 사용되는 재귀적 구현. obj의 형을 사용하여 호출할 포매팅 메서드를 결정하고, obj 와 level을 전달합니다. 형별 메서드는 재귀적 포매팅을 수행하기 위해 repr1()을 호출해야 하는데, 재귀 호출에서 level 값으로 level - 1을 사용합니다.

Repr.repr_TYPE(obj, level)

특정 형의 포매팅 메서드는 형 이름에 기반하는 이름의 메서드로 구현됩니다. 메서드 이름에서, TYPE 은 '_'.join(type(obj).__name__.split())으로 치환됩니다. 이 메서드로의 디스패치는 repr1()에 의해 처리됩니다. 재귀적으로 값을 포맷해야 하는 형별 메서드는 self.repr1(subobj, level - 1)을 호출해야 합니다.

Repr 객체 서브 클래싱

The use of dynamic dispatching by Repr.repr1() allows subclasses of Repr to add support for additional built-in object types or to modify the handling of types already supported. This example shows how special support for file objects could be added:

import reprlib
import sys

class MyRepr(reprlib.Repr):

    def repr_TextIOWrapper(self, obj, level):
        if obj.name in {'<stdin>', '<stdout>', '<stderr>'}:
            return obj.name
        return repr(obj)

aRepr = MyRepr()
print(aRepr.repr(sys.stdin))         # prints '<stdin>'

<stdin>

enum — Support for enumerations

Added in version 3.4.

소스 코드: Lib/enum.py [https://github.com/python/cpython/tree/main/Lib/enum.py]

Important

This page contains the API reference information. For tutorial information and discussion of more advanced topics, see

Basic Tutorial

Advanced Tutorial

Enum Cookbook

An enumeration:

is a set of symbolic names (members) bound to unique values

can be iterated over to return its canonical (i.e. non-alias) members in definition order

uses call syntax to return members by value

uses index syntax to return members by name

Enumerations are created either by using class syntax, or by using function-call syntax:

>>> from enum import Enum

>>> # class syntax
>>> class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 3

>>> # functional syntax
>>> Color = Enum('Color', [('RED', 1), ('GREEN', 2), ('BLUE', 3)])

Even though we can use class syntax to create Enums, Enums are not normal Python classes. See How are Enums different? for more details.

참고

명명법

The class Color is an enumeration (or enum)

The attributes Color.RED, Color.GREEN, etc., are enumeration members (or members) and are functionally constants.

The enum members have names and values (the name of Color.RED is RED, the value of Color.BLUE is 3, etc.)

모듈 내용

EnumType

The type for Enum and its subclasses.

Enum

Base class for creating enumerated constants.

IntEnum

Base class for creating enumerated constants that are also subclasses of int. (Notes)

StrEnum

Base class for creating enumerated constants that are also subclasses of str. (Notes)

Flag

Flag 멤버십을 잃지 않고 비트 연산을 사용하여 결합할 수 있는 열거형 상수를 만들기 위한 베이스 클래스.

IntFlag

Base class for creating enumerated constants that can be combined using the bitwise operators without losing their IntFlag membership. IntFlag members are also subclasses of int. (Notes)

ReprEnum

Used by IntEnum, StrEnum, and IntFlag to keep the str() of the mixed-in type.

EnumCheck

An enumeration with the values CONTINUOUS, NAMED_FLAGS, and UNIQUE, for use with verify() to ensure various constraints are met by a given enumeration.

FlagBoundary

An enumeration with the values STRICT, CONFORM, EJECT, and KEEP which allows for more fine-grained control over how invalid values are dealt with in an enumeration.

auto

Instances are replaced with an appropriate value for Enum members. StrEnum defaults to the lower-cased version of the member name, while other Enums default to 1 and increase from there.

property()

Allows Enum members to have attributes without conflicting with member names. The value and name attributes are implemented this way.

unique()

한 값에 하나의 이름 만 연결되도록 하는 Enum 클래스 데코레이터.

verify()

Enum class decorator that checks user-selectable constraints on an enumeration.

member()

Make obj a member. Can be used as a decorator.

nonmember()

Do not make obj a member. Can be used as a decorator.

global_enum()

Modify the str() and repr() of an enum to show its members as belonging to the module instead of its class, and export the enum members to the global namespace.

show_flag_values()

Return a list of all power-of-two integers contained in a flag.

Added in version 3.6: Flag, IntFlag, auto

Added in version 3.11: StrEnum, EnumCheck, ReprEnum, FlagBoundary, property, member, nonmember, global_enum, show_flag_values

Data Types

class enum.EnumType

EnumType is the metaclass for enum enumerations. It is possible to subclass EnumType – see Subclassing EnumType for details.

EnumType is responsible for setting the correct __repr__(), __str__(), __format__(), and __reduce__() methods on the final enum, as well as creating the enum members, properly handling duplicates, providing iteration over the enum class, etc.

__call__(cls, value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

This method is called in two different ways:

to look up an existing member:

cls:

The enum class being called.

value:

The value to lookup.

to use the cls enum to create a new enum (only if the existing enum does not have any members):

cls:

The enum class being called.

value:

The name of the new Enum to create.

names:

The names/values of the members for the new Enum.

module:

The name of the module the new Enum is created in.

qualname:

The actual location in the module where this Enum can be found.

type:

A mix-in type for the new Enum.

start:

The first integer value for the Enum (used by auto).

boundary:

How to handle out-of-range values from bit operations (Flag only).

__contains__(cls, member)

Returns True if member belongs to the cls:

>>> some_var = Color.RED
>>> some_var in Color
True
>>> Color.RED.value in Color
True

버전 3.12에서 변경: Before Python 3.12, a TypeError is raised if a non-Enum-member is used in a containment check.

__dir__(cls)

Returns ['__class__', '__doc__', '__members__', '__module__'] and the names of the members in cls:

>>> dir(Color)
['BLUE', 'GREEN', 'RED', '__class__', '__contains__', '__doc__', '__getitem__', '__init_subclass__', '__iter__', '__len__', '__members__', '__module__', '__name__', '__qualname__']

__getitem__(cls, name)

Returns the Enum member in cls matching name, or raises a KeyError:

>>> Color['BLUE']
<Color.BLUE: 3>

__iter__(cls)

Returns each member in cls in definition order:

>>> list(Color)
[<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 3>]

__len__(cls)

Returns the number of member in cls:

>>> len(Color)
3

__members__

Returns a mapping of every enum name to its member, including aliases

__reversed__(cls)

Returns each member in cls in reverse definition order:

>>> list(reversed(Color))
[<Color.BLUE: 3>, <Color.GREEN: 2>, <Color.RED: 1>]

_add_alias_()

Adds a new name as an alias to an existing member. Raises a NameError if the name is already assigned to a different member.

_add_value_alias_()

Adds a new value as an alias to an existing member. Raises a ValueError if the value is already linked with a different member.

Added in version 3.11: Before 3.11 EnumType was called EnumMeta, which is still available as an alias.

class enum.Enum

Enum is the base class for all enum enumerations.

name

The name used to define the Enum member:

>>> Color.BLUE.name
'BLUE'

value

The value given to the Enum member:

>>> Color.RED.value
1

Value of the member, can be set in __new__().

참고

Enum 멤버 값

Member values can be anything: int, str, etc. If the exact value is unimportant you may use auto instances and an appropriate value will be chosen for you. See auto for the details.

While mutable/unhashable values, such as dict, list or a mutable dataclass, can be used, they will have a quadratic performance impact during creation relative to the total number of mutable/unhashable values in the enum.

_name_

Name of the member.

_value_

Value of the member, can be set in __new__().

_order_

No longer used, kept for backward compatibility. (class attribute, removed during class creation).

_ignore_

_ignore_ is only used during creation and is removed from the enumeration once creation is complete.

_ignore_ is a list of names that will not become members, and whose names will also be removed from the completed enumeration. See TimePeriod for an example.

__dir__(self)

Returns ['__class__', '__doc__', '__module__', 'name', 'value'] and any public methods defined on self.__class__:

>>> from datetime import date
>>> class Weekday(Enum):
...     MONDAY = 1
...     TUESDAY = 2
...     WEDNESDAY = 3
...     THURSDAY = 4
...     FRIDAY = 5
...     SATURDAY = 6
...     SUNDAY = 7
...     @classmethod
...     def today(cls):
...         print('today is %s' % cls(date.today().isoweekday()).name)
...
>>> dir(Weekday.SATURDAY)
['__class__', '__doc__', '__eq__', '__hash__', '__module__', 'name', 'today', 'value']

_generate_next_value_(name, start, count, last_values)

name:

The name of the member being defined (e.g. ‘RED’).

start:

The start value for the Enum; the default is 1.

count:

The number of members currently defined, not including this one.

last_values:

A list of the previous values.

A staticmethod that is used to determine the next value returned by auto:

>>> from enum import auto
>>> class PowersOfThree(Enum):
...     @staticmethod
...     def _generate_next_value_(name, start, count, last_values):
...         return 3 ** (count + 1)
...     FIRST = auto()
...     SECOND = auto()
...
>>> PowersOfThree.SECOND.value
9

__init__(self, *args, **kwds)

By default, does nothing. If multiple values are given in the member assignment, those values become separate arguments to __init__; e.g.

>>> from enum import Enum
>>> class Weekday(Enum):
...     MONDAY = 1, 'Mon'

Weekday.__init__() would be called as Weekday.__init__(self, 1, 'Mon')

__init_subclass__(cls, **kwds)

A classmethod that is used to further configure subsequent subclasses. By default, does nothing.

_missing_(cls, value)

A classmethod for looking up values not found in cls. By default it does nothing, but can be overridden to implement custom search behavior:

>>> from enum import StrEnum
>>> class Build(StrEnum):
...     DEBUG = auto()
...     OPTIMIZED = auto()
...     @classmethod
...     def _missing_(cls, value):
...         value = value.lower()
...         for member in cls:
...             if member.value == value:
...                 return member
...         return None
...
>>> Build.DEBUG.value
'debug'
>>> Build('deBUG')
<Build.DEBUG: 'debug'>

__new__(cls, *args, **kwds)

By default, doesn’t exist. If specified, either in the enum class definition or in a mixin class (such as int), all values given in the member assignment will be passed; e.g.

>>> from enum import Enum
>>> class MyIntEnum(int, Enum):
...     TWENTYSIX = '1a', 16

results in the call int('1a', 16) and a value of 26 for the member.

참고

When writing a custom __new__, do not use super().__new__ – call the appropriate __new__ instead.

__repr__(self)

Returns the string used for repr() calls. By default, returns the Enum name, member name, and value, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __repr__(self):
...         cls_name = self.__class__.__name__
...         return f'{cls_name}.{self.name}'
...
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(OtherStyle.ALTERNATE, 'OtherStyle.ALTERNATE', 'OtherStyle.ALTERNATE')

__str__(self)

Returns the string used for str() calls. By default, returns the Enum name and member name, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __str__(self):
...         return f'{self.name}'
...
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(<OtherStyle.ALTERNATE: 1>, 'ALTERNATE', 'ALTERNATE')

__format__(self)

Returns the string used for format() and f-string calls. By default, returns __str__() return value, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __format__(self, spec):
...         return f'{self.name}'
...
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(<OtherStyle.ALTERNATE: 1>, 'OtherStyle.ALTERNATE', 'ALTERNATE')

참고

Using auto with Enum results in integers of increasing value, starting with 1.

버전 3.12에서 변경: Added Dataclass support

class enum.IntEnum

IntEnum is the same as Enum, but its members are also integers and can be used anywhere that an integer can be used. If any integer operation is performed with an IntEnum member, the resulting value loses its enumeration status.

>>> from enum import IntEnum
>>> class Number(IntEnum):
...     ONE = 1
...     TWO = 2
...     THREE = 3
...
>>> Number.THREE
<Number.THREE: 3>
>>> Number.ONE + Number.TWO
3
>>> Number.THREE + 5
8
>>> Number.THREE == 3
True

참고

Using auto with IntEnum results in integers of increasing value, starting with 1.

버전 3.11에서 변경: __str__() is now int.__str__() to better support the replacement of existing constants use-case. __format__() was already int.__format__() for that same reason.

class enum.StrEnum

StrEnum is the same as Enum, but its members are also strings and can be used in most of the same places that a string can be used. The result of any string operation performed on or with a StrEnum member is not part of the enumeration.

참고

There are places in the stdlib that check for an exact str instead of a str subclass (i.e. type(unknown) == str instead of isinstance(unknown, str)), and in those locations you will need to use str(StrEnum.member).

참고

Using auto with StrEnum results in the lower-cased member name as the value.

참고

__str__() is str.__str__() to better support the replacement of existing constants use-case. __format__() is likewise str.__format__() for that same reason.

Added in version 3.11.

class enum.Flag

Flag is the same as Enum, but its members support the bitwise operators & (AND), | (OR), ^ (XOR), and ~ (INVERT); the results of those operations are (aliases of) members of the enumeration.

__contains__(self, value)

Returns True if value is in self:

>>> from enum import Flag, auto
>>> class Color(Flag):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> purple = Color.RED | Color.BLUE
>>> white = Color.RED | Color.GREEN | Color.BLUE
>>> Color.GREEN in purple
False
>>> Color.GREEN in white
True
>>> purple in white
True
>>> white in purple
False

__iter__(self):

Returns all contained non-alias members:

>>> list(Color.RED)
[<Color.RED: 1>]
>>> list(purple)
[<Color.RED: 1>, <Color.BLUE: 4>]

Added in version 3.11.

__len__(self):

Returns number of members in flag:

>>> len(Color.GREEN)
1
>>> len(white)
3

Added in version 3.11.

__bool__(self):

Returns True if any members in flag, False otherwise:

>>> bool(Color.GREEN)
True
>>> bool(white)
True
>>> black = Color(0)
>>> bool(black)
False

__or__(self, other)

Returns current flag binary or’ed with other:

>>> Color.RED | Color.GREEN
<Color.RED|GREEN: 3>

__and__(self, other)

Returns current flag binary and’ed with other:

>>> purple & white
<Color.RED|BLUE: 5>
>>> purple & Color.GREEN
<Color: 0>

__xor__(self, other)

Returns current flag binary xor’ed with other:

>>> purple ^ white
<Color.GREEN: 2>
>>> purple ^ Color.GREEN
<Color.RED|GREEN|BLUE: 7>

__invert__(self):

Returns all the flags in type(self) that are not in self:

>>> ~white
<Color: 0>
>>> ~purple
<Color.GREEN: 2>
>>> ~Color.RED
<Color.GREEN|BLUE: 6>

_numeric_repr_()

Function used to format any remaining unnamed numeric values. Default is the value’s repr; common choices are hex() and oct().

참고

Using auto with Flag results in integers that are powers of two, starting with 1.

버전 3.11에서 변경: The repr() of zero-valued flags has changed. It is now:

>>> Color(0)
<Color: 0>

class enum.IntFlag

IntFlag is the same as Flag, but its members are also integers and can be used anywhere that an integer can be used.

>>> from enum import IntFlag, auto
>>> class Color(IntFlag):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> Color.RED & 2
<Color: 0>
>>> Color.RED | 2
<Color.RED|GREEN: 3>

If any integer operation is performed with an IntFlag member, the result is not an IntFlag:

>>> Color.RED + 2
3

If a Flag operation is performed with an IntFlag member and:

the result is a valid IntFlag: an IntFlag is returned

the result is not a valid IntFlag: the result depends on the FlagBoundary setting

The repr() of unnamed zero-valued flags has changed. It is now:

>>> Color(0)
<Color: 0>

참고

Using auto with IntFlag results in integers that are powers of two, starting with 1.

버전 3.11에서 변경: __str__() is now int.__str__() to better support the replacement of existing constants use-case. __format__() was already int.__format__() for that same reason.

Inversion of an IntFlag now returns a positive value that is the union of all flags not in the given flag, rather than a negative value. This matches the existing Flag behavior.

class enum.ReprEnum

ReprEnum uses the repr() of Enum, but the str() of the mixed-in data type:

int.__str__() for IntEnum and IntFlag

str.__str__() for StrEnum

Inherit from ReprEnum to keep the str() / format() of the mixed-in data type instead of using the Enum-default str().

Added in version 3.11.

class enum.EnumCheck

EnumCheck contains the options used by the verify() decorator to ensure various constraints; failed constraints result in a ValueError.

UNIQUE

Ensure that each value has only one name:

>>> from enum import Enum, verify, UNIQUE
>>> @verify(UNIQUE)
... class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 3
...     CRIMSON = 1
Traceback (most recent call last):
...
ValueError: aliases found in <enum 'Color'>: CRIMSON -> RED

CONTINUOUS

Ensure that there are no missing values between the lowest-valued member and the highest-valued member:

>>> from enum import Enum, verify, CONTINUOUS
>>> @verify(CONTINUOUS)
... class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 5
Traceback (most recent call last):
...
ValueError: invalid enum 'Color': missing values 3, 4

NAMED_FLAGS

Ensure that any flag groups/masks contain only named flags – useful when values are specified instead of being generated by auto():

>>> from enum import Flag, verify, NAMED_FLAGS
>>> @verify(NAMED_FLAGS)
... class Color(Flag):
...     RED = 1
...     GREEN = 2
...     BLUE = 4
...     WHITE = 15
...     NEON = 31
Traceback (most recent call last):
...
ValueError: invalid Flag 'Color': aliases WHITE and NEON are missing combined values of 0x18 [use enum.show_flag_values(value) for details]

참고

CONTINUOUS and NAMED_FLAGS are designed to work with integer-valued members.

Added in version 3.11.

class enum.FlagBoundary

FlagBoundary controls how out-of-range values are handled in Flag and its subclasses.

STRICT

Out-of-range values cause a ValueError to be raised. This is the default for Flag:

>>> from enum import Flag, STRICT, auto
>>> class StrictFlag(Flag, boundary=STRICT):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> StrictFlag(2**2 + 2**4)
Traceback (most recent call last):
...
ValueError: <flag 'StrictFlag'> invalid value 20
    given 0b0 10100
  allowed 0b0 00111

CONFORM

Out-of-range values have invalid values removed, leaving a valid Flag value:

>>> from enum import Flag, CONFORM, auto
>>> class ConformFlag(Flag, boundary=CONFORM):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> ConformFlag(2**2 + 2**4)
<ConformFlag.BLUE: 4>

EJECT

Out-of-range values lose their Flag membership and revert to int.

>>> from enum import Flag, EJECT, auto
>>> class EjectFlag(Flag, boundary=EJECT):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> EjectFlag(2**2 + 2**4)
20

KEEP

Out-of-range values are kept, and the Flag membership is kept. This is the default for IntFlag:

>>> from enum import Flag, KEEP, auto
>>> class KeepFlag(Flag, boundary=KEEP):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...
>>> KeepFlag(2**2 + 2**4)
<KeepFlag.BLUE|16: 20>

Added in version 3.11.

지원되는 __dunder__ 이름

__members__ is a read-only ordered mapping of member_name:member items. It is only available on the class.

__new__(), if specified, must create and return the enum members; it is also a very good idea to set the member’s _value_ appropriately. Once all the members are created it is no longer used.

지원되는 _sunder_ 이름

_add_alias_() – adds a new name as an alias to an existing member.

_add_value_alias_() – adds a new value as an alias to an existing member.

_name_ – name of the member

_value_ – value of the member; can be set in __new__

_missing_() – a lookup function used when a value is not found; may be overridden

_ignore_ – a list of names, either as a list or a str, that will not be transformed into members, and will be removed from the final class

_order_ – no longer used, kept for backward compatibility (class attribute, removed during class creation)

_generate_next_value_() – used to get an appropriate value for an enum member; may be overridden

참고

For standard Enum classes the next value chosen is the highest value seen incremented by one.

For Flag classes the next value chosen will be the next highest power-of-two.

While _sunder_ names are generally reserved for the further development of the Enum class and can not be used, some are explicitly allowed:

_repr_* (e.g. _repr_html_), as used in IPython’s rich display [https://ipython.readthedocs.io/en/stable/config/integrating.html#rich-display]

Added in version 3.6: _missing_, _order_, _generate_next_value_

Added in version 3.7: _ignore_

Added in version 3.13: _add_alias_, _add_value_alias_, _repr_*

Utilities and Decorators

class enum.auto

auto can be used in place of a value. If used, the Enum machinery will call an Enum’s _generate_next_value_() to get an appropriate value. For Enum and IntEnum that appropriate value will be the last value plus one; for Flag and IntFlag it will be the first power-of-two greater than the highest value; for StrEnum it will be the lower-cased version of the member’s name. Care must be taken if mixing auto() with manually specified values.

auto instances are only resolved when at the top level of an assignment:

FIRST = auto() will work (auto() is replaced with 1);

SECOND = auto(), -2 will work (auto is replaced with 2, so 2, -2 is used to create the SECOND enum member;

THREE = [auto(), -3] will not work (<auto instance>, -3 is used to create the THREE enum member)

버전 3.11.1에서 변경: In prior versions, auto() had to be the only thing on the assignment line to work properly.

_generate_next_value_ can be overridden to customize the values used by auto.

참고

in 3.13 the default _generate_next_value_ will always return the highest member value incremented by 1, and will fail if any member is an incompatible type.

@enum.property

A decorator similar to the built-in property, but specifically for enumerations. It allows member attributes to have the same names as members themselves.

참고

the property and the member must be defined in separate classes; for example, the value and name attributes are defined in the Enum class, and Enum subclasses can define members with the names value and name.

Added in version 3.11.

@enum.unique

A class decorator specifically for enumerations. It searches an enumeration’s __members__, gathering any aliases it finds; if any are found ValueError is raised with the details:

>>> from enum import Enum, unique
>>> @unique
... class Mistake(Enum):
...     ONE = 1
...     TWO = 2
...     THREE = 3
...     FOUR = 3
...
Traceback (most recent call last):
...
ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE

@enum.verify

A class decorator specifically for enumerations. Members from EnumCheck are used to specify which constraints should be checked on the decorated enumeration.

Added in version 3.11.

@enum.member

A decorator for use in enums: its target will become a member.

Added in version 3.11.

@enum.nonmember

A decorator for use in enums: its target will not become a member.

Added in version 3.11.

@enum.global_enum

A decorator to change the str() and repr() of an enum to show its members as belonging to the module instead of its class. Should only be used when the enum members are exported to the module global namespace (see re.RegexFlag for an example).

Added in version 3.11.

enum.show_flag_values(value)

Return a list of all power-of-two integers contained in a flag value.

Added in version 3.11.

Notes

IntEnum, StrEnum, and IntFlag

These three enum types are designed to be drop-in replacements for existing integer- and string-based values; as such, they have extra limitations:

__str__ uses the value and not the name of the enum member

__format__, because it uses __str__, will also use the value of the enum member instead of its name

If you do not need/want those limitations, you can either create your own base class by mixing in the int or str type yourself:

>>> from enum import Enum
>>> class MyIntEnum(int, Enum):
...     pass

or you can reassign the appropriate str(), etc., in your enum:

>>> from enum import Enum, IntEnum
>>> class MyIntEnum(IntEnum):
...     __str__ = Enum.__str__

graphlib — Functionality to operate with graph-like structures

소스 코드: Lib/graphlib.py [https://github.com/python/cpython/tree/main/Lib/graphlib.py]

class graphlib.TopologicalSorter(graph=None)

Provides functionality to topologically sort a graph of hashable nodes.

위상 순서(topological order)는 그래프(graph)에서 꼭짓점(vertex)의 선형 순서로, 꼭짓점 u에서 꼭짓점 v로 가는 모든 유향 변(directed edge) u -> v 에 대해, 꼭짓점 u가 꼭짓점 v보다 앞에 옵니다. 예를 들어, 그래프의 꼭짓점은 수행될 작업을 나타낼 수 있고, 변은 하나의 작업이 다른 작업보다 먼저 수행되어야 한다는 제약을 나타낼 수 있습니다; 이 예에서, 위상 순서는 유효한 작업 순서입니다. 그래프에 유향 순환이 없는 경우, 즉 유향 비순환 그래프인 경우에만 완전한 위상 정렬이 가능합니다.

선택적 graph 인자가 제공되면 키가 노드이고 값이 그래프에서 해당 노드의 모든 선행 노드(키의 값을 가리키는 변이 있는 노드)의 이터러블인 비순환 그래프를 나타내는 딕셔너리이어야 합니다). add() 메서드를 사용하여 그래프에 추가 노드를 추가할 수 있습니다.

일반적으로, 주어진 그래프의 정렬을 수행하는 데 필요한 단계는 다음과 같습니다:

선택적 초기 그래프를 사용하여 TopologicalSorter의 인스턴스를 만듭니다.

그래프에 노드를 추가합니다.

그래프에서 prepare()를 호출합니다.

is_active()가 True인 동안, get_ready()가 반환하는 노드를 이터레이트하고 이들을 처리합니다. 처리가 완료됨에 따라, 각 노드에 done()을 호출합니다.

그래프에서 노드의 즉각적인 정렬이 필요하고 병렬화가 개입하지 않으면, 편의 메서드 TopologicalSorter.static_order()를 직접 사용할 수 있습니다:

>>> graph = {"D": {"B", "C"}, "C": {"A"}, "B": {"A"}}
>>> ts = TopologicalSorter(graph)
>>> tuple(ts.static_order())
('A', 'C', 'B', 'D')

이 클래스는 노드가 준비됨에 따라 병렬 처리를 쉽게 지원하도록 설계되었습니다. 예를 들어:

topological_sorter = TopologicalSorter()

# Add nodes to 'topological_sorter'...

topological_sorter.prepare()
while topological_sorter.is_active():
    for node in topological_sorter.get_ready():
        # Worker threads or processes take nodes to work on off the
        # 'task_queue' queue.
        task_queue.put(node)

    # When the work for a node is done, workers put the node in
    # 'finalized_tasks_queue' so we can get more nodes to work on.
    # The definition of 'is_active()' guarantees that, at this point, at
    # least one node has been placed on 'task_queue' that hasn't yet
    # been passed to 'done()', so this blocking 'get()' must (eventually)
    # succeed.  After calling 'done()', we loop back to call 'get_ready()'
    # again, so put newly freed nodes on 'task_queue' as soon as
    # logically possible.
    node = finalized_tasks_queue.get()
    topological_sorter.done(node)

add(node, *predecessors)

Add a new node and its predecessors to the graph. Both the node and all elements in predecessors must be hashable.

같은 노드 인자로 여러 번 호출되면, 종속성 집합은 전달된 모든 종속성의 합집합입니다.

종속성이 없는 노드를 추가하거나(predecessors가 제공되지 않는 경우) 종속성을 두 번 제공할 수 있습니다. 이전에 제공되지 않은 노드가 predecessors에 포함되면, 노드는 그 자신의 선행 노드 없이 자동으로 그래프에 추가됩니다.

prepare() 이후에 호출되면 ValueError가 발생합니다.

prepare()

그래프를 완료로 표시하고 그래프에서 순환을 검사합니다. 순환이 감지되면, CycleError가 발생하지만, 순환이 더 진행하는 것을 차단할 때까지 get_ready()를 사용하여 여전히 가능한 많은 노드를 얻을 수 있습니다. 이 함수를 호출한 후에는, 그래프를 수정할 수 없어서, add()를 사용하여 더는 노드를 추가할 수 없습니다.

is_active()

더 진행할 수 있으면 True를, 그렇지 않으면 False를 반환합니다. 순환이 결정을 차단하지 않고 TopologicalSorter.get_ready()에 의해 아직 반환되지 않은 준비된 노드가 아직 있거나 TopologicalSorter.done()으로 표시된 노드 수가 TopologicalSorter.get_ready()에 의해 반환된 수보다 작으면 진행할 수 있습니다.

The __bool__() method of this class defers to this function, so instead of:

if ts.is_active():
    ...

다음처럼 간단하게 할 수 있습니다:

if ts:
    ...

이전에 prepare()를 호출하지 않고 호출되면 ValueError가 발생합니다.

done(*nodes)

TopologicalSorter.get_ready()에 의해 반환된 노드 집합이 처리된 것으로 표시하여, nodes에 있는 각 노드의 모든 후속 노드들이 TopologicalSorter.get_ready()에 대한 호출로 나중에 반환되도록 차단 해제합니다.

nodes에 있는 노드가 이 메서드에 대한 이전 호출에 의해 이미 처리된 것으로 표시되었거나 TopologicalSorter.add()를 사용하여 그래프에 추가되지 않았거나, prepare()를 호출하지 않고 호출되었거나, 또는 get_ready()가 아직 노드를 반환하지 않았으면 ValueError를 발생시킵니다.

get_ready()

준비된 모든 노드가 담긴 tuple을 반환합니다. 처음에는 선행 노드가 없는 모든 노드를 반환하며, 일단 TopologicalSorter.done()을 호출하여 처리된 것으로 표시되면, 추가 호출은 모든 선행 노드가 이미 처리된 모든 새 노드를 반환합니다. 더는 진행할 수 없으면, 빈 튜플이 반환됩니다.

이전에 prepare()를 호출하지 않고 호출되면 ValueError가 발생합니다.

static_order()

Returns an iterator object which will iterate over nodes in a topological order. When using this method, prepare() and done() should not be called. This method is equivalent to:

def static_order(self):
    self.prepare()
    while self.is_active():
        node_group = self.get_ready()
        yield from node_group
        self.done(*node_group)

반환되는 특정 순서는 항목이 그래프에 삽입된 특정 순서에 따라 달라질 수 있습니다. 예를 들면:

>>> ts = TopologicalSorter()
>>> ts.add(3, 2, 1)
>>> ts.add(1, 0)
>>> print([*ts.static_order()])
[2, 0, 1, 3]

>>> ts2 = TopologicalSorter()
>>> ts2.add(1, 0)
>>> ts2.add(3, 2, 1)
>>> print([*ts2.static_order()])
[0, 2, 1, 3]

이것은 그래프에서 “0”과 “2”가 같은 수준에 있고 (get_ready()에 대한 같은 호출에서 반환됩니다) 이들 간의 순서는 삽입 순서에 따라 결정되기 때문입니다.

순환이 감지되면 CycleError가 발생합니다.

Added in version 3.9.

예외

graphlib 모듈은 다음 예외를 정의합니다:

exception graphlib.CycleError

작업 그래프에 순환이 있으면 TopologicalSorter.prepare()가 발생시키는 ValueError의 서브 클래스. 여러 순환이 존재하면, 그들 중 오직 하나의 정의되지 않은 선택만 보고되고 예외에 포함됩니다.

The detected cycle can be accessed via the second element in the args attribute of the exception instance and consists in a list of nodes, such that each node is, in the graph, an immediate predecessor of the next node in the list. In the reported list, the first and the last node will be the same, to make it clear that it is cyclic.

숫자와 수학 모듈

이 장에 나와있는 모듈들은 숫자와 수학에 관련된 함수와 데이터 타입을 제공합니다. numbers 모듈은 숫자 데이터 타입을 위한 추상 계층 구조를 정의합니다. math 와 cmath 모듈은 부동소수와 복소수를 위한 여러 수학 함수를 가지고 있습니다. decimal 모듈은 임의의 정밀도 계산을 사용하여 정확한 10진수 표현을 지원합니다.

이 장에는 다음과 같은 모듈이 설명되어 있습니다:

numbers — Numeric abstract base classes

Number

숫자 계층

Complex

real

imag

conjugate()

Real

Rational

numerator

denominator

Integral

Notes for type implementers

더 많은 숫자 추상 베이스 클래스(ABC) 추가

산술 연산 구현

math — Mathematical functions

Number-theoretic functions

comb()

factorial()

gcd()

isqrt()

lcm()

perm()

Floating point arithmetic

ceil()

fabs()

floor()

fma()

fmod()

modf()

remainder()

trunc()

Floating point manipulation functions

copysign()

frexp()

isclose()

isfinite()

isinf()

isnan()

ldexp()

nextafter()

ulp()

Power, exponential and logarithmic functions

cbrt()

exp()

exp2()

expm1()

log()

log1p()

log2()

log10()

pow()

sqrt()

Summation and product functions

dist()

fsum()

hypot()

prod()

sumprod()

각도 변환

degrees()

radians()

삼각 함수

acos()

asin()

atan()

atan2()

cos()

sin()

tan()

쌍곡선 함수

acosh()

asinh()

atanh()

cosh()

sinh()

tanh()

특수 함수

erf()

erfc()

gamma()

lgamma()

상수

pi

e

tau

inf

nan

cmath — Mathematical functions for complex numbers

극좌표 변환

phase()

polar()

rect()

거듭제곱과 로그 함수

exp()

log()

log10()

sqrt()

삼각 함수

acos()

asin()

atan()

cos()

sin()

tan()

쌍곡선(hyperbolic) 함수

acosh()

asinh()

atanh()

cosh()

sinh()

tanh()

분류 함수

isfinite()

isinf()

isnan()

isclose()

상수

pi

e

tau

inf

infj

nan

nanj

decimal — Decimal fixed-point and floating-point arithmetic

빠른 시작 자습서

Decimal 객체

Decimal

adjusted()

as_integer_ratio()

as_tuple()

canonical()

compare()

compare_signal()

compare_total()

compare_total_mag()

conjugate()

copy_abs()

copy_negate()

copy_sign()

exp()

from_float()

from_number()

fma()

is_canonical()

is_finite()

is_infinite()

is_nan()

is_normal()

is_qnan()

is_signed()

is_snan()

is_subnormal()

is_zero()

ln()

log10()

logb()

logical_and()

logical_invert()

logical_or()

logical_xor()

max()

max_mag()

min()

min_mag()

next_minus()

next_plus()

next_toward()

normalize()

number_class()

quantize()

radix()

remainder_near()

rotate()

same_quantum()

scaleb()

shift()

sqrt()

to_eng_string()

to_integral()

to_integral_exact()

to_integral_value()

논리적 피연산자

Context 객체

getcontext()

setcontext()

localcontext()

BasicContext

ExtendedContext

DefaultContext

Context

clear_flags()

clear_traps()

copy()

copy_decimal()

create_decimal()

create_decimal_from_float()

Etiny()

Etop()

abs()

add()

canonical()

compare()

compare_signal()

compare_total()

compare_total_mag()

copy_abs()

copy_negate()

copy_sign()

divide()

divide_int()

divmod()

exp()

fma()

is_canonical()

is_finite()

is_infinite()

is_nan()

is_normal()

is_qnan()

is_signed()

is_snan()

is_subnormal()

is_zero()

ln()

log10()

logb()

logical_and()

logical_invert()

logical_or()

logical_xor()

max()

max_mag()

min()

min_mag()

minus()

multiply()

next_minus()

next_plus()

next_toward()

normalize()

number_class()

plus()

power()

quantize()

radix()

remainder()

remainder_near()

rotate()

same_quantum()

scaleb()

shift()

sqrt()

subtract()

to_eng_string()

to_integral_exact()

to_sci_string()

상수

MAX_PREC

MAX_EMAX

MIN_EMIN

MIN_ETINY

HAVE_THREADS

HAVE_CONTEXTVAR

자리 올림 모드

ROUND_CEILING

ROUND_DOWN

ROUND_FLOOR

ROUND_HALF_DOWN

ROUND_HALF_EVEN

ROUND_HALF_UP

ROUND_UP

ROUND_05UP

신호

Clamped

DecimalException

DivisionByZero

Inexact

InvalidOperation

Overflow

Rounded

Subnormal

Underflow

FloatOperation

Floating-Point Notes

증가시킨 정밀도로 자리 올림 오차 줄이기

특수 값

스레드로 작업하기

조리법

Decimal FAQ

fractions — Rational numbers

Fraction

numerator

denominator

as_integer_ratio()

is_integer()

from_float()

from_decimal()

from_number()

limit_denominator()

__floor__()

__ceil__()

__round__()

__format__()

random — Generate pseudo-random numbers

관리 함수

seed()

getstate()

setstate()

바이트열 함수

randbytes()

정수 함수

randrange()

randint()

getrandbits()

시퀀스 함수

choice()

choices()

shuffle()

sample()

Discrete distributions

binomialvariate()

실수 분포

random()

uniform()

triangular()

betavariate()

expovariate()

gammavariate()

gauss()

lognormvariate()

normalvariate()

vonmisesvariate()

paretovariate()

weibullvariate()

대체 생성기

Random

seed()

getstate()

setstate()

random()

getrandbits()

SystemRandom

재현성에 대한 참고 사항

예제

조리법

Command-line usage

Command-line example

statistics — Mathematical statistics functions

평균과 중심 위치의 측정

분산 측정

Statistics for relations between two inputs

함수 세부 사항

mean()

fmean()

geometric_mean()

harmonic_mean()

kde()

kde_random()

median()

median_low()

median_high()

median_grouped()

mode()

multimode()

pstdev()

pvariance()

stdev()

variance()

quantiles()

covariance()

correlation()

linear_regression()

예외

StatisticsError

NormalDist 객체

NormalDist

mean

median

mode

stdev

variance

from_samples()

samples()

pdf()

cdf()

inv_cdf()

overlap()

quantiles()

zscore()

Examples and Recipes

Classic probability problems

Monte Carlo inputs for simulations

Approximating binomial distributions

Naive bayesian classifier

numbers — Numeric abstract base classes

소스 코드: Lib/numbers.py [https://github.com/python/cpython/tree/main/Lib/numbers.py]

The numbers module (PEP 3141 [https://peps.python.org/pep-3141/]) defines a hierarchy of numeric abstract base classes which progressively define more operations. None of the types defined in this module are intended to be instantiated.

class numbers.Number

숫자 계층의 최상위 클래스입니다. 형에 상관없이 인자 x 가 숫자인지 확인하려면 isinstance(x, Number) 를 사용하세요.

숫자 계층

class numbers.Complex

Subclasses of this type describe complex numbers and include the operations that work on the built-in complex type. These are: conversions to complex and bool, real, imag, +, -, *, /, **, abs(), conjugate(), ==, and !=. All except - and != are abstract.

real

추상. 복소수의 실수부를 반환합니다.

imag

추상. 복소수의 허수부를 반환합니다.

abstractmethod conjugate()

추상 메서드. 켤레 복소수를 반환합니다. 예를 들어 (1+3j).conjugate() == (1-3j) 입니다.

class numbers.Real

To Complex, Real adds the operations that work on real numbers.

요약하면 float 로의 변환과 math.trunc(), round(), math.floor(), math.ceil(), divmod(), //, %, <, <=, >, >= 가 포함됩니다.

이 클래스는 또한 complex(), real, imag, conjugate() 를 위한 기본값을 제공합니다.

class numbers.Rational

Subtypes Real and adds numerator and denominator properties. It also provides a default for float().

The numerator and denominator values should be instances of Integral and should be in lowest terms with denominator positive.

numerator

프로퍼티(추상 메서드)

denominator

프로퍼티(추상 메서드)

class numbers.Integral

Subtypes Rational and adds a conversion to int. Provides defaults for float(), numerator, and denominator. Adds abstract methods for pow() with modulus and bit-string operations: <<, >>, &, ^, |, ~.

Notes for type implementers

Implementers should be careful to make equal numbers equal and hash them to the same values. This may be subtle if there are two different extensions of the real numbers. For example, fractions.Fraction implements hash() as follows:

def __hash__(self):
    if self.denominator == 1:
        # Get integers right.
        return hash(self.numerator)
    # Expensive check, but definitely correct.
    if self == float(self):
        return hash(float(self))
    else:
        # Use tuple's hash to avoid a high collision rate on
        # simple fractions.
        return hash((self.numerator, self.denominator))

더 많은 숫자 추상 베이스 클래스(ABC) 추가

물론 숫자를 위한 ABC를 추가하는 것이 가능합니다. 그렇지 않으면 엉망으로 상속 계층이 구현될 것입니다. Complex 와 Real 사이에 다음과 같이 MyFoo 를 추가할 수 있습니다:

class MyFoo(Complex): ...
MyFoo.register(Real)

산술 연산 구현

We want to implement the arithmetic operations so that mixed-mode operations either call an implementation whose author knew about the types of both arguments, or convert both to the nearest built in type and do the operation there. For subtypes of Integral, this means that __add__() and __radd__() should be defined as:

class MyIntegral(Integral):

    def __add__(self, other):
        if isinstance(other, MyIntegral):
            return do_my_adding_stuff(self, other)
        elif isinstance(other, OtherTypeIKnowAbout):
            return do_my_other_adding_stuff(self, other)
        else:
            return NotImplemented

    def __radd__(self, other):
        if isinstance(other, MyIntegral):
            return do_my_adding_stuff(other, self)
        elif isinstance(other, OtherTypeIKnowAbout):
            return do_my_other_adding_stuff(other, self)
        elif isinstance(other, Integral):
            return int(other) + int(self)
        elif isinstance(other, Real):
            return float(other) + float(self)
        elif isinstance(other, Complex):
            return complex(other) + complex(self)
        else:
            return NotImplemented

Complex 클래스의 서브클래스에는 다섯 가지의 서로 다른 혼합형 연산이 있습니다. 위의 코드에서 MyIntegral 와 OtherTypeIKnowAbout 를 제외한 나머지를 기본구조라고 하겠습니다. a 는 Complex 의 하위 형인 A 의 인스턴스입니다(즉 a : A <: Complex 입니다). 비슷하게 b : B <: Complex 입니다. a + b 인 경우를 생각해 보겠습니다:

If A defines an __add__() which accepts b, all is well.

If A falls back to the boilerplate code, and it were to return a value from __add__(), we’d miss the possibility that B defines a more intelligent __radd__(), so the boilerplate should return NotImplemented from __add__(). (Or A may not implement __add__() at all.)

Then B’s __radd__() gets a chance. If it accepts a, all is well.

기본구조 코드로 돌아온다면 더 시도해 볼 수 있는 메서드가 없으므로 기본적으로 수행될 구현을 작성해야 합니다.

만약 B <: A 라면 파이썬은 A.__add__ 메서드 전에 B.__radd__ 를 시도합니다. A 에 대해서 알고 B 가 구현되었기 때문에 이런 행동은 문제없습니다. 따라서 Complex 에 위임하기 전에 이 인스턴스를 처리할 수 있습니다.

If A <: Complex and B <: Real without sharing any other knowledge, then the appropriate shared operation is the one involving the built in complex, and both __radd__() s land there, so a+b == b+a.

대부분 주어진 어떤 형에 대한 연산은 매우 비슷하므로, 주어진 연산자의 정방향(forward) 인스턴스와 역방향(reverse) 인스턴스를 생성하는 헬퍼 함수를 정의하는 것이 유용합니다. 예를 들어 fractions.Fraction 클래스는 다음과 같이 사용합니다:

def _operator_fallbacks(monomorphic_operator, fallback_operator):
    def forward(a, b):
        if isinstance(b, (int, Fraction)):
            return monomorphic_operator(a, b)
        elif isinstance(b, float):
            return fallback_operator(float(a), b)
        elif isinstance(b, complex):
            return fallback_operator(complex(a), b)
        else:
            return NotImplemented
    forward.__name__ = '__' + fallback_operator.__name__ + '__'
    forward.__doc__ = monomorphic_operator.__doc__

    def reverse(b, a):
        if isinstance(a, Rational):
            # Includes ints.
            return monomorphic_operator(a, b)
        elif isinstance(a, Real):
            return fallback_operator(float(a), float(b))
        elif isinstance(a, Complex):
            return fallback_operator(complex(a), complex(b))
        else:
            return NotImplemented
    reverse.__name__ = '__r' + fallback_operator.__name__ + '__'
    reverse.__doc__ = monomorphic_operator.__doc__

    return forward, reverse

def _add(a, b):
    """a + b"""
    return Fraction(a.numerator * b.denominator +
                    b.numerator * a.denominator,
                    a.denominator * b.denominator)

__add__, __radd__ = _operator_fallbacks(_add, operator.add)

# ...

math — Mathematical functions

이 모듈은 C 표준에서 정의된 수학 함수에 대한 액세스를 제공합니다.

이 함수는 복소수와 함께 사용할 수 없습니다; 복소수를 지원해야 하면 cmath 모듈에 있는 같은 이름의 함수를 사용하십시오. 대부분 사용자는 복소수를 이해하는 데 필요한 수준의 수학을 배우고 싶어 하지 않기 때문에 복소수를 지원하는 함수와 그렇지 않은 함수를 구별했습니다. 복소수 결과 대신 예외를 수신하면 매개 변수로 사용된 예상치 못한 복소수를 조기에 감지할 수 있기 때문에, 프로그래머는 처음 위치에서 생성된 경로와 원인을 파악할 수 있습니다.

이 모듈에서 제공하는 함수는 다음과 같습니다. 달리 명시되지 않는 한 모든 반환 값은 float입니다.

Number-theoretic functions

comb(n, k)

Number of ways to choose k items from n items without repetition and without order

factorial(n)

n factorial

gcd(*integers)

Greatest common divisor of the integer arguments

isqrt(n)

Integer square root of a nonnegative integer n

lcm(*integers)

Least common multiple of the integer arguments

perm(n, k)

Number of ways to choose k items from n items without repetition and with order

Floating point arithmetic

ceil(x)

Ceiling of x, the smallest integer greater than or equal to x

fabs(x)

Absolute value of x

floor(x)

Floor of x, the largest integer less than or equal to x

fma(x, y, z)

Fused multiply-add operation: (x * y) + z

fmod(x, y)

Remainder of division x / y

modf(x)

Fractional and integer parts of x

remainder(x, y)

Remainder of x with respect to y

trunc(x)

Integer part of x

Floating point manipulation functions

copysign(x, y)

Magnitude (absolute value) of x with the sign of y

frexp(x)

Mantissa and exponent of x

isclose(a, b, rel_tol, abs_tol)

Check if the values a and b are close to each other

isfinite(x)

Check if x is neither an infinity nor a NaN

isinf(x)

Check if x is a positive or negative infinity

isnan(x)

Check if x is a NaN (not a number)

ldexp(x, i)

x * (2**i), inverse of function frexp()

nextafter(x, y, steps)

Floating-point value steps steps after x towards y

ulp(x)

Value of the least significant bit of x

Power, exponential and logarithmic functions

cbrt(x)

Cube root of x

exp(x)

e raised to the power x

exp2(x)

2 raised to the power x

expm1(x)

e raised to the power x, minus 1

log(x, base)

Logarithm of x to the given base (e by default)

log1p(x)

Natural logarithm of 1+x (base e)

log2(x)

Base-2 logarithm of x

log10(x)

Base-10 logarithm of x

pow(x, y)

x raised to the power y

sqrt(x)

Square root of x

Summation and product functions

dist(p, q)

Euclidean distance between two points p and q given as an iterable of coordinates

fsum(iterable)

Sum of values in the input iterable

hypot(*coordinates)

Euclidean norm of an iterable of coordinates

prod(iterable, start)

Product of elements in the input iterable with a start value

sumprod(p, q)

Sum of products from two iterables p and q

Angular conversion

degrees(x)

Convert angle x from radians to degrees

radians(x)

Convert angle x from degrees to radians

Trigonometric functions

acos(x)

Arc cosine of x

asin(x)

Arc sine of x

atan(x)

Arc tangent of x

atan2(y, x)

atan(y / x)

cos(x)

Cosine of x

sin(x)

Sine of x

tan(x)

Tangent of x

Hyperbolic functions

acosh(x)

Inverse hyperbolic cosine of x

asinh(x)

Inverse hyperbolic sine of x

atanh(x)

Inverse hyperbolic tangent of x

cosh(x)

Hyperbolic cosine of x

sinh(x)

Hyperbolic sine of x

tanh(x)

Hyperbolic tangent of x

Special functions

erf(x)

Error function [https://en.wikipedia.org/wiki/Error_function] at x

erfc(x)

Complementary error function [https://en.wikipedia.org/wiki/Error_function] at x

gamma(x)

Gamma function [https://en.wikipedia.org/wiki/Gamma_function] at x

lgamma(x)

Natural logarithm of the absolute value of the Gamma function [https://en.wikipedia.org/wiki/Gamma_function] at x

Constants

pi

π = 3.141592…

e

e = 2.718281…

tau

τ = 2π = 6.283185…

inf

Positive infinity

nan

“Not a number” (NaN)

Number-theoretic functions

math.comb(n, k)

반복과 순서 없이 n 개의 항목에서 k 개의 항목을 선택하는 방법의 수를 반환합니다.

k <= n이면 n! / (k! * (n - k)!)로 평가되고, k > n이면 0으로 평가됩니다.

Also called the binomial coefficient because it is equivalent to the coefficient of k-th term in polynomial expansion of (1 + x)ⁿ.

인자 중 어느 하나라도 정수가 아니면 TypeError를 발생시킵니다. 인자 중 어느 하나라도 음수이면 ValueError를 발생시킵니다.

Added in version 3.8.

math.factorial(n)

Return n factorial as an integer. Raises ValueError if n is not integral or is negative.

버전 3.10에서 변경: Floats with integral values (like 5.0) are no longer accepted.

math.gcd(*integers)

지정된 정수 인자의 최대 공약수를 반환합니다. 인자 중 하나가 0이 아니면, 반환된 값은 모든 인자를 나누는 가장 큰 양의 정수입니다. 모든 인자가 0이면, 반환 값은 0입니다. 인자가 없는 gcd()는 0을 반환합니다.

Added in version 3.5.

버전 3.9에서 변경: 임의의 개수 인자에 대한 지원이 추가되었습니다. 이전에는, 단지 두 개의 인자만 지원되었습니다.

math.isqrt(n)

음이 아닌 정수 n의 정수 제곱근을 반환합니다. 이것은 n의 정확한 제곱근의 바닥(floor)입니다, 또는, 동등하게, a² ≤ n을 만족하는 가장 큰 정수 a입니다.

일부 응용 프로그램에서는, n ≤ a² 을 만족하는 가장 작은 정수 a, 즉 n의 정확한 제곱근의 천장(ceiling)을 구하는 것이 더 편리합니다. 양의 n에 대해, 이것은 a = 1 + isqrt(n - 1)을 사용하여 계산할 수 있습니다.

Added in version 3.8.

math.lcm(*integers)

지정된 정수 인자의 최소 공배수를 반환합니다. 모든 인자가 0이 아니면, 반환 값은 모든 인자의 배수인 가장 작은 양의 정수입니다. 인자 중 어느 하나가 0이면, 반환 값은 0입니다. 인자가 없는 lcm()은 1을 반환합니다.

Added in version 3.9.

math.perm(n, k=None)

반복 없고 순서 있게 n 개의 항목에서 k 개의 항목을 선택하는 방법의 수를 반환합니다.

k <= n이면 n! / (n - k)! 로 평가되고, k > n이면 0으로 평가됩니다.

If k is not specified or is None, then k defaults to n and the function returns n!.

인자 중 어느 하나라도 정수가 아니면 TypeError를 발생시킵니다. 인자 중 어느 하나라도 음수이면 ValueError를 발생시킵니다.

Added in version 3.8.

Floating point arithmetic

math.ceil(x)

Return the ceiling of x, the smallest integer greater than or equal to x. If x is not a float, delegates to x.__ceil__, which should return an Integral value.

math.fabs(x)

x의 절댓값을 반환합니다.

math.floor(x)

Return the floor of x, the largest integer less than or equal to x. If x is not a float, delegates to x.__floor__, which should return an Integral value.

math.fma(x, y, z)

Fused multiply-add operation. Return (x * y) + z, computed as though with infinite precision and range followed by a single round to the float format. This operation often provides better accuracy than the direct expression (x * y) + z.

This function follows the specification of the fusedMultiplyAdd operation described in the IEEE 754 standard. The standard leaves one case implementation-defined, namely the result of fma(0, inf, nan) and fma(inf, 0, nan). In these cases, math.fma returns a NaN, and does not raise any exception.

Added in version 3.13.

math.fmod(x, y)

플랫폼 C 라이브러리에서 정의한 대로 fmod(x, y)를 반환합니다. 파이썬 표현식 x % y가 같은 결과를 반환하지 않을 수 있음에 유의하십시오. C 표준의 의도는 어떤 정수 n에 대해 fmod(x, y)가 x - n*y와 정확히 (수학적으로; 무한 정밀도로) 같고, 결과는 x와 같은 부호를 가지며 크기(절댓값)는 abs(y)보다 작아지도록 하는 것입니다. 파이썬의 x % y는 대신 y의 부호를 갖는 결과를 반환하며 float 인자에 대해 정확하게 계산할 수 없을 수 있습니다. 예를 들어, fmod(-1e-100, 1e100)는 -1e-100이지만, 파이썬의 -1e-100 % 1e100의 결과는 1e100-1e-100이며, 부동 소수점으로 정확하게 표현할 수 없어서, 의외의 1e100으로 반올림됩니다. 이러한 이유로, 함수 fmod()는 일반적으로 float로 작업할 때 선호되는 반면 파이썬의 x % y는 정수로 작업할 때 선호됩니다.

math.modf(x)

x의 소수와 정수 부분을 반환합니다. 두 결과 모두 x의 부호를 가지며 float입니다.

Note that modf() has a different call/return pattern than its C equivalents: it takes a single argument and return a pair of values, rather than returning its second return value through an ‘output parameter’ (there is no such thing in Python).

math.remainder(x, y)

y에 대한 x의 IEEE 754 스타일 나머지를 반환합니다. 유한한 x 와 0이 아닌 유한한 y에 대해, 이것은 차이 x - n*y입니다. 여기서 n은 몫 x / y의 정확한 값에 가장 가까운 정수입니다. x / y가 두 개의 인접한 정수 사이의 정확히 중간이면, 가장 가까운 짝수 정수가 n으로 사용됩니다. 따라서 나머지 r = remainder(x, y)는 항상 abs(r) <= 0.5 * abs(y)를 만족합니다.

IEEE 754에 따른 특별한 경우: 특히, remainder(x, math.inf)는 모든 유한한 x에 대해서는 x이고, remainder(x, 0)과 remainder(math.inf, x)는 모든 NaN이 아닌 x에 대해 ValueError를 발생시킵니다. 나머지 연산의 결과가 0이면, 해당 0은 x 와 같은 부호를 갖습니다.

On platforms using IEEE 754 binary floating point, the result of this operation is always exactly representable: no rounding error is introduced.

Added in version 3.7.

math.trunc(x)

Return x with the fractional part removed, leaving the integer part. This rounds toward 0: trunc() is equivalent to floor() for positive x, and equivalent to ceil() for negative x. If x is not a float, delegates to x.__trunc__, which should return an Integral value.

ceil(), floor() 및 modf() 함수의 경우, 충분히 큰 절댓값을 갖는 모든 부동 소수점 숫자는 정확한 정수입니다. 파이썬 float는 일반적으로 53비트 이하의 정밀도를 가지는데 (플랫폼 C double 형과 같습니다), 이때 abs(x) >= 2**52를 만족하는 모든 float x는 소수 비트를 갖지 않습니다.

Floating point manipulation functions

math.copysign(x, y)

x의 크기(절댓값)와 y의 부호를 갖는 float를 반환합니다. 부호 있는 0을 지원하는 플랫폼에서, copysign(1.0, -0.0)은 -1.0을 반환합니다.

math.frexp(x)

x의 가수(mantissa)와 지수(exponent)를 (m, e) 쌍으로 반환합니다. m은 float이고, e는 정수이며, 정확히 x == m * 2**e가 성립합니다. x가 0이면, (0.0, 0)을 반환하고, 그렇지 않으면 0.5 <= abs(m) < 1입니다. 이것은 float의 내부 표현을 이식성 있는 방식으로 “분리”하는 데 사용됩니다.

Note that frexp() has a different call/return pattern than its C equivalents: it takes a single argument and return a pair of values, rather than returning its second return value through an ‘output parameter’ (there is no such thing in Python).

math.isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0)

값 a와 b가 서로 가까이 있으면 True를, 그렇지 않으면 False를 반환합니다.

Whether or not two values are considered close is determined according to given absolute and relative tolerances. If no errors occur, the result will be: abs(a-b) <= max(rel_tol * max(abs(a), abs(b)), abs_tol).

rel_tol is the relative tolerance – it is the maximum allowed difference between a and b, relative to the larger absolute value of a or b. For example, to set a tolerance of 5%, pass rel_tol=0.05. The default tolerance is 1e-09, which assures that the two values are the same within about 9 decimal digits. rel_tol must be nonnegative and less than 1.0.

abs_tol is the absolute tolerance; it defaults to 0.0 and it must be nonnegative. When comparing x to 0.0, isclose(x, 0) is computed as abs(x) <= rel_tol  * abs(x), which is False for any x and rel_tol less than 1.0. So add an appropriate positive abs_tol argument to the call.

IEEE 754 특수 값 NaN, inf 및 -inf는 IEEE 규칙에 따라 처리됩니다. 특히, NaN은 NaN을 포함하여 다른 어떤 값과도 근접한 것으로 간주하지 않습니다. inf와 -inf는 오직 자신과만 가까운 것으로 간주합니다.

Added in version 3.5.

더 보기

PEP 485 [https://peps.python.org/pep-0485/] – 근사적 동등성을 검사하는 함수

math.isfinite(x)

x가 무한대나 NaN이 아니면 True를, 그렇지 않으면 False를 반환합니다. (0.0은 유한한 것으로 간주합니다.)

Added in version 3.2.

math.isinf(x)

x가 양 또는 음의 무한대이면 True를, 그렇지 않으면 False를 반환합니다.

math.isnan(x)

x가 NaN(not a number)이면 True를, 그렇지 않으면 False를 반환합니다.

math.ldexp(x, i)

x * (2**i)를 반환합니다. 이것은 본질적으로 함수 frexp()의 역입니다.

math.nextafter(x, y, steps=1)

Return the floating-point value steps steps after x towards y.

If x is equal to y, return y, unless steps is zero.

예:

math.nextafter(x, math.inf)는 올라갑니다: 양의 무한대를 향해.

math.nextafter(x, -math.inf)는 내려갑니다: 음의 무한대를 향해.

math.nextafter(x, 0.0)는 0을 향합니다.

math.nextafter(x, math.copysign(math.inf, x))는 0에서 멀어집니다.

math.ulp()도 참조하십시오.

Added in version 3.9.

버전 3.12에서 변경: Added the steps argument.

math.ulp(x)

float x의 최하위 비트 값을 반환합니다:

x가 NaN(not a number)이면, x를 반환합니다.

x가 음수이면, ulp(-x)를 반환합니다.

x가 양의 무한대이면, x를 반환합니다.

x가 0과 같으면, 가장 작은 양의 정규화되지 않은(denormalized) 표현 가능한 float를 반환합니다 (가장 작은 양의 정규화된 float, sys.float_info.min보다 작습니다).

x가 가장 큰 양의 표현 가능한 float와 같으면, x보다 작은 첫 번째 float가 x - ulp(x)가 되도록, x의 최하위 비트 값을 반환합니다.

그렇지 않으면 (x가 양의 유한 수이면), x보다 큰 첫 번째 float가 x + ulp(x)가 되도록, x의 최하위 비트 값을 반환합니다.

ULP는 “Unit in the Last Place(마지막 자리의 단위)”를 나타냅니다.

math.nextafter()와 sys.float_info.epsilon도 참조하십시오.

Added in version 3.9.

Power, exponential and logarithmic functions

math.cbrt(x)

Return the cube root of x.

Added in version 3.11.

math.exp(x)

e의 x 거듭제곱을 반환합니다. 여기서 e = 2.718281… 는 자연로그의 밑(base)입니다. 일반적으로 math.e ** x나 pow(math.e, x)보다 정확합니다.

math.exp2(x)

Return 2 raised to the power x.

Added in version 3.11.

math.expm1(x)

Return e raised to the power x, minus 1. Here e is the base of natural logarithms. For small floats x, the subtraction in exp(x) - 1 can result in a significant loss of precision [https://en.wikipedia.org/wiki/Loss_of_significance]; the expm1() function provides a way to compute this quantity to full precision:

>>> from math import exp, expm1
>>> exp(1e-5) - 1  # gives result accurate to 11 places
1.0000050000069649e-05
>>> expm1(1e-5)    # result accurate to full precision
1.0000050000166668e-05

Added in version 3.2.

math.log(x[, base])

하나의 인자를 제공하면, x의 자연로그를 반환합니다 (밑 e).

두 개의 인자를 제공하면, 주어진 밑(base)으로 x의 로그를 반환합니다, log(x)/log(base)로 계산합니다.

math.log1p(x)

1+x의 자연로그를 반환합니다 (밑 e). 결과는 0에 가까운 x에 대해 정확한 방식으로 계산됩니다.

math.log2(x)

x의 밑이 2인 로그를 반환합니다. 이것은 일반적으로 log(x, 2)보다 정확합니다.

Added in version 3.3.

더 보기

int.bit_length()는 부호와 선행 0을 제외하고 정수를 이진수로 나타내는 데 필요한 비트 수를 반환합니다.

math.log10(x)

x의 밑이 10인 로그를 반환합니다. 이것은 일반적으로 log(x, 10)보다 정확합니다.

math.pow(x, y)

Return x raised to the power y. Exceptional cases follow the IEEE 754 standard as far as possible. In particular, pow(1.0, x) and pow(x, 0.0) always return 1.0, even when x is a zero or a NaN. If both x and y are finite, x is negative, and y is not an integer then pow(x, y) is undefined, and raises ValueError.

내장 ** 연산자와 달리, math.pow()는 두 인자를 모두 float 형으로 변환합니다. 정확한 정수 거듭제곱을 계산하려면 **나 내장 pow() 함수를 사용하십시오.

버전 3.11에서 변경: The special cases pow(0.0, -inf) and pow(-0.0, -inf) were changed to return inf instead of raising ValueError, for consistency with IEEE 754.

math.sqrt(x)

x의 제곱근을 반환합니다.

Summation and product functions

math.dist(p, q)

각각 좌표 시퀀스(또는 이터러블)로 제공되는, 두 점 p와 q 사이의 유클리드 거리를 반환합니다. 두 점의 차원(dimension)은 같아야 합니다.

대략 다음과 동등합니다:

sqrt(sum((px - qx) ** 2.0 for px, qx in zip(p, q)))

Added in version 3.8.

math.fsum(iterable)

Return an accurate floating-point sum of values in the iterable. Avoids loss of precision by tracking multiple intermediate partial sums.

알고리즘의 정확도는 IEEE-754 산술의 보증과 자리 올림 모드가 짝수로 반올림(half-even)인 일반적인 경우에 의존합니다. 윈도우 이외의 일부 빌드에서, 하부 C 라이브러리는 확장 정밀도 덧셈을 사용하고, 때때로 중간 합을 이중 자리 올림(double-round) 하여 최하위 비트(least significant bit)에서 분리할 수 있습니다.

For further discussion and two alternative approaches, see the ASPN cookbook recipes for accurate floating-point summation [https://code.activestate.com/recipes/393090-binary-floating-point-summation-accurate-to-full-p/].

math.hypot(*coordinates)

유클리드 크기(norm) sqrt(sum(x**2 for x in coordinates))를 반환합니다. 원점에서 coordinates로 지정된 점까지의 벡터의 길이입니다.

2차원 점 (x, y)의 경우, 피타고라스 정리를 사용하여 직각 삼각형의 빗변(hypotenuse)을 계산하는 것과 동등합니다, sqrt(x*x + y*y).

버전 3.8에서 변경: n 차원 점에 대한 지원이 추가되었습니다. 이전에는, 2차원인 경우만 지원되었습니다.

버전 3.10에서 변경: Improved the algorithm’s accuracy so that the maximum error is under 1 ulp (unit in the last place). More typically, the result is almost always correctly rounded to within 1/2 ulp.

math.prod(iterable, *, start=1)

입력 이터러블(iterable)에 있는 모든 요소의 곱을 계산합니다. 곱의 기본 start 값은 1입니다.

iterable이 비어 있으면, start 값을 반환합니다. 이 함수는 숫자 값과 함께 사용하기 위한 것으로, 숫자가 아닌 형을 거부 할 수 있습니다.

Added in version 3.8.

math.sumprod(p, q)

Return the sum of products of values from two iterables p and q.

Raises ValueError if the inputs do not have the same length.

대략 다음과 동등합니다:

sum(map(operator.mul, p, q, strict=True))

For float and mixed int/float inputs, the intermediate products and sums are computed with extended precision.

Added in version 3.12.

각도 변환

math.degrees(x)

각도 x를 라디안에서 도(degree)로 변환합니다.

math.radians(x)

각도 x를 도(degree)에서 라디안으로 변환합니다.

삼각 함수

math.acos(x)

x의 아크 코사인(arc cosine)을 라디안으로 반환합니다. 결과는 0과 pi 사이입니다.

math.asin(x)

x의 아크 사인(arc sine)을 라디안으로 반환합니다. 결과는 -pi/2와 pi/2 사이입니다.

math.atan(x)

x의 아크 탄젠트(arc tangent)를 라디안으로 반환합니다. 결과는 -pi/2와 pi/2 사이입니다.

math.atan2(y, x)

atan(y / x)를 라디안으로 반환합니다. 결과는 -pi와 pi 사이입니다. 평면에 있는 원점에서 점 (x, y)까지의 벡터는 양의 X 축과 이 각도를 이룹니다. atan2()의 요점은 두 입력의 부호가 모두 알려져 있기 때문에 각도에 대한 정확한 사분면을 계산할 수 있다는 것입니다. 예를 들어, atan(1)과 atan2(1, 1)은 모두 pi/4이지만, atan2(-1, -1)은 -3*pi/4입니다.

math.cos(x)

x 라디안의 코사인(cosine)을 반환합니다.

math.sin(x)

x 라디안의 사인(sine)을 반환합니다.

math.tan(x)

x 라디안의 탄젠트(tangent)를 반환합니다.

쌍곡선 함수

Hyperbolic functions [https://en.wikipedia.org/wiki/Hyperbolic_functions] are analogs of trigonometric functions that are based on hyperbolas instead of circles.

math.acosh(x)

x의 역 쌍곡 코사인(inverse hyperbolic cosine)을 반환합니다.

math.asinh(x)

x의 역 쌍곡 사인(inverse hyperbolic sine)을 반환합니다.

math.atanh(x)

x의 역 쌍곡 탄젠트(inverse hyperbolic tangent)를 반환합니다.

math.cosh(x)

x의 쌍곡 코사인(hyperbolic cosine)을 반환합니다.

math.sinh(x)

x의 쌍곡 사인(hyperbolic sine)을 반환합니다.

math.tanh(x)

x의 쌍곡 탄젠트(hyperbolic tangent)를 반환합니다.

특수 함수

math.erf(x)

x의 오차 함수(error function) [https://en.wikipedia.org/wiki/Error_function]를 반환합니다.

The erf() function can be used to compute traditional statistical functions such as the cumulative standard normal distribution [https://en.wikipedia.org/wiki/Cumulative_distribution_function]:

def phi(x):
    'Cumulative distribution function for the standard normal distribution'
    return (1.0 + erf(x / sqrt(2.0))) / 2.0

Added in version 3.2.

math.erfc(x)

x의 여오차 함수를 반환합니다. 여오차 함수(complementary error function) [https://en.wikipedia.org/wiki/Error_function]는 1.0 - erf(x)로 정의됩니다. 뺄셈으로 인해 유효 숫자의 소실 [https://en.wikipedia.org/wiki/Loss_of_significance]이 발생하는 x의 큰 값에 사용됩니다.

Added in version 3.2.

math.gamma(x)

x의 감마 함수(Gamma function) [https://en.wikipedia.org/wiki/Gamma_function]를 반환합니다.

Added in version 3.2.

math.lgamma(x)

x의 감마 함수의 절댓값의 자연로그를 반환합니다.

Added in version 3.2.

상수

math.pi

사용 가능한 정밀도로, 수학 상수 π = 3.141592…

math.e

사용 가능한 정밀도로, 수학 상수 e = 2.718281…

math.tau

사용 가능한 정밀도로, 수학 상수 τ = 6.283185… 타우(tau)는 원주와 반지름의 비율인 2π에 해당하는 원 상수입니다. 타우에 대한 자세한 내용은, Vi Hart의 비디오 Pi is (still) Wrong [https://www.youtube.com/watch?v=jG7vhMMXagQ]dmf 확인하고, 두 배의 파이를 먹는 것으로 타우 데이(Tau day) [https://tauday.com/]를 축하하십시오!

Added in version 3.6.

math.inf

부동 소수점 양의 무한대. (음의 무한대는 -math.inf를 사용하십시오.) float('inf')의 출력과 동등합니다.

Added in version 3.5.

math.nan

A floating-point “not a number” (NaN) value. Equivalent to the output of float('nan'). Due to the requirements of the IEEE-754 standard [https://en.wikipedia.org/wiki/IEEE_754], math.nan and float('nan') are not considered to equal to any other numeric value, including themselves. To check whether a number is a NaN, use the isnan() function to test for NaNs instead of is or ==. Example:

>>> import math
>>> math.nan == math.nan
False
>>> float('nan') == float('nan')
False
>>> math.isnan(math.nan)
True
>>> math.isnan(float('nan'))
True

Added in version 3.5.

버전 3.11에서 변경: It is now always available.

CPython 구현 상세: math 모듈은 대부분 플랫폼 C 수학 라이브러리 함수 주위의 얇은 래퍼로 구성됩니다. 예외적인 경우의 행동은 적절한 경우 C99 표준의 부록 F를 따릅니다. 현재 구현은 sqrt(-1.0)이나 log(0.0)과 같은 잘못된 연산의 경우 ValueError를 발생시키고 (C99 부록 F에서 잘못된 연산이나 0으로 나누기를 신호를 주도록 권장하는 경우), 오버플로 하는 결과(예를 들어, exp(1000.0))의 경우 OverflowError를 발생시킵니다. 하나 이상의 입력 인자가 NaN이 아니면, NaN은 위의 함수에서 반환되지 않습니다; 입력 인자가 NaN이면 대부분 함수는 NaN을 반환하지만, (다시 한번 C99 부록 F를 따라) 이 규칙에는 예를 들어 pow(float('nan'), 0.0)이나 hypot(float('nan'), float('inf'))와 같은 몇 가지 예외가 있습니다.

파이썬은 신호를 주는 NaN(signaling NaN)을 조용한 NaN(quiet NaN)과 구별하기 위해 노력하지 않으며, 신호를 주는 NaN의 동작은 지정되지 않은 상태로 남아 있습니다. 일반적인 동작은 모든 NaN을 조용한 것으로 취급하는 것입니다.

더 보기

모듈 cmath

이 함수 중 많은 것들의 복소수 버전.

cmath — Mathematical functions for complex numbers

This module provides access to mathematical functions for complex numbers. The functions in this module accept integers, floating-point numbers or complex numbers as arguments. They will also accept any Python object that has either a __complex__() or a __float__() method: these methods are used to convert the object to a complex or floating-point number, respectively, and the function is then applied to the result of the conversion.

참고

For functions involving branch cuts, we have the problem of deciding how to define those functions on the cut itself. Following Kahan’s “Branch cuts for complex elementary functions” paper, as well as Annex G of C99 and later C standards, we use the sign of zero to distinguish one side of the branch cut from the other: for a branch cut along (a portion of) the real axis we look at the sign of the imaginary part, while for a branch cut along the imaginary axis we look at the sign of the real part.

For example, the cmath.sqrt() function has a branch cut along the negative real axis. An argument of -2-0j is treated as though it lies below the branch cut, and so gives a result on the negative imaginary axis:

>>> cmath.sqrt(-2-0j)
-1.4142135623730951j

But an argument of -2+0j is treated as though it lies above the branch cut:

>>> cmath.sqrt(-2+0j)
1.4142135623730951j

극좌표 변환

A Python complex number z is stored internally using rectangular or Cartesian coordinates. It is completely determined by its real part z.real and its imaginary part z.imag.

극좌표(polar coordinates)는 복소수를 나타내는 다른 방법을 제공합니다. 극좌표에서, 복소수 z는 모듈러스(modulus) r과 위상 각(phase angle) phi로 정의됩니다. 모듈러스 r은 z에서 원점까지의 거리이며, 위상 phi는 양의 x축에서 원점과 z를 잇는 선분으로의 라디안(radian)으로 측정한 반 시계 방향 각도입니다.

네이티브 직교 좌표와 극좌표 간의 변환에 다음 함수를 사용할 수 있습니다.

cmath.phase(x)

Return the phase of x (also known as the argument of x), as a float. phase(x) is equivalent to math.atan2(x.imag, x.real). The result lies in the range [-π, π], and the branch cut for this operation lies along the negative real axis. The sign of the result is the same as the sign of x.imag, even when x.imag is zero:

>>> phase(-1+0j)
3.141592653589793
>>> phase(-1-0j)
-3.141592653589793

참고

복소수 x의 모듈러스(절댓값)는 내장 abs() 함수를 사용하여 계산할 수 있습니다. 이 연산을 위한 별도의 cmath 모듈 함수는 없습니다.

cmath.polar(x)

x 표현을 극좌표로 반환합니다. 쌍 (r, phi)를 반환합니다. 여기서 r은 x의 모듈러스이고 phi는 x의 위상입니다. polar(x)는 (abs(x), phase(x))와 동등합니다.

cmath.rect(r, phi)

Return the complex number x with polar coordinates r and phi. Equivalent to complex(r * math.cos(phi), r * math.sin(phi)).

거듭제곱과 로그 함수

cmath.exp(x)

e의 x 거듭제곱을 반환합니다. 여기서 e는 자연로그(natural logarithms)의 밑입니다.

cmath.log(x[, base])

Returns the logarithm of x to the given base. If the base is not specified, returns the natural logarithm of x. There is one branch cut, from 0 along the negative real axis to -∞.

cmath.log10(x)

x의 밑이 10인 로그를 반환합니다. 이것은 log()와 같은 분지 절단을 가집니다.

cmath.sqrt(x)

x의 제곱근을 반환합니다. 이것은 log()와 같은 분지 절단을 가집니다.

삼각 함수

cmath.acos(x)

Return the arc cosine of x. There are two branch cuts: One extends right from 1 along the real axis to ∞. The other extends left from -1 along the real axis to -∞.

cmath.asin(x)

x의 아크 사인을 반환합니다. 이것은 acos()와 같은 분지 절단을 가집니다.

cmath.atan(x)

Return the arc tangent of x. There are two branch cuts: One extends from 1j along the imaginary axis to ∞j. The other extends from -1j along the imaginary axis to -∞j.

cmath.cos(x)

x의 코사인을 반환합니다.

cmath.sin(x)

x의 사인을 반환합니다.

cmath.tan(x)

x의 탄젠트를 반환합니다.

쌍곡선(hyperbolic) 함수

cmath.acosh(x)

Return the inverse hyperbolic cosine of x. There is one branch cut, extending left from 1 along the real axis to -∞.

cmath.asinh(x)

Return the inverse hyperbolic sine of x. There are two branch cuts: One extends from 1j along the imaginary axis to ∞j. The other extends from -1j along the imaginary axis to -∞j.

cmath.atanh(x)

Return the inverse hyperbolic tangent of x. There are two branch cuts: One extends from 1 along the real axis to ∞. The other extends from -1 along the real axis to -∞.

cmath.cosh(x)

x의 쌍곡선 코사인을 반환합니다.

cmath.sinh(x)

x의 쌍곡선 사인을 반환합니다.

cmath.tanh(x)

x의 쌍곡선 탄젠트를 반환합니다.

분류 함수

cmath.isfinite(x)

x의 실수부와 허수부가 모두 유한이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

Added in version 3.2.

cmath.isinf(x)

x의 실수부나 허수부 중 하나가 무한이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

cmath.isnan(x)

x의 실수부나 허수부 중 하나가 NaN이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

cmath.isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0)

a와 b 값이 서로 가까우면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

Whether or not two values are considered close is determined according to given absolute and relative tolerances. If no errors occur, the result will be: abs(a-b) <= max(rel_tol * max(abs(a), abs(b)), abs_tol).

rel_tol is the relative tolerance – it is the maximum allowed difference between a and b, relative to the larger absolute value of a or b. For example, to set a tolerance of 5%, pass rel_tol=0.05. The default tolerance is 1e-09, which assures that the two values are the same within about 9 decimal digits. rel_tol must be nonnegative and less than 1.0.

abs_tol is the absolute tolerance; it defaults to 0.0 and it must be nonnegative. When comparing x to 0.0, isclose(x, 0) is computed as abs(x) <= rel_tol  * abs(x), which is False for any x and rel_tol less than 1.0. So add an appropriate positive abs_tol argument to the call.

IEEE 754 특수 값 NaN, inf 및 -inf는 IEEE 규칙에 따라 처리됩니다. 특히, NaN은 NaN을 포함한 다른 모는 값과 가깝다고 간주하지 않습니다. inf와 -inf는 그들 자신하고만 가깝다고 간주합니다.

Added in version 3.5.

더 보기

PEP 485 [https://peps.python.org/pep-0485/] – 근사 동등을 검사하는 함수.

상수

cmath.pi

수학 상수 π의 float 값.

cmath.e

수학 상수 e의 float 값.

cmath.tau

수학 상수 τ의 float 값.

Added in version 3.6.

cmath.inf

부동 소수점 양의 무한대. float('inf')와 동등합니다.

Added in version 3.6.

cmath.infj

0 실수부와 양의 무한대 허수부를 갖는 복소수. complex(0.0, float('inf'))와 동등합니다.

Added in version 3.6.

cmath.nan

부동 소수점 “not a number” (NaN) 값. float('nan')과 동등합니다.

Added in version 3.6.

cmath.nanj

0 실수부와 NaN 허수부를 갖는 복소수. complex(0.0, float('nan'))과 동등합니다.

Added in version 3.6.

함수 선택은 모듈 math에서와 유사하지만 동일하지는 않습니다. 두 개의 모듈이 있는 이유는 일부 사용자가 복소수에 관심이 없고, 어쩌면 복소수가 무엇인지 모를 수도 있기 때문입니다. 그들에게는 math.sqrt(-1)이 복소수를 반환하기보다 예외를 발생시키는 것이 좋습니다. 또한, cmath에 정의된 함수는, 결과를 실수로 표현할 수 있을 때도 항상 복소수를 반환합니다 (이때 복소수의 허수부는 0입니다).

분지 절단에 대한 참고 사항: 주어진 함수가 연속적이지 않은 점을 지나는 곡선입니다. 이것들은 많은 복소수 기능에서 필요한 기능입니다. 복소수 함수로 계산해야 할 때, 분지 절단에 대해 이해가 필요하다고 가정합니다. 이해를 위해서는 복소 변수에 관한 (너무 기초적이지 않은) 아무 책이나 참고하면 됩니다. 수치 계산의 목적으로 분지 절단을 적절히 선택하는 방법에 대한 정보에 대해서는, 다음과 같은 좋은 참고 문헌이 있습니다:

더 보기

Kahan, W: Branch cuts for complex elementary functions; or, Much ado about nothing’s sign bit. Iserles, A., and Powell, M. (eds.), The state of the art in numerical analysis. Clarendon Press (1987) pp165–211.

decimal — Decimal fixed-point and floating-point arithmetic

소스 코드: Lib/decimal.py [https://github.com/python/cpython/tree/main/Lib/decimal.py]

The decimal module provides support for fast correctly rounded decimal floating-point arithmetic. It offers several advantages over the float datatype:

Decimal “은 사람을 염두에 두고 설계된 부동 소수점 모델에 기반하고, 필연적으로 최고 원리를 갖습니다 – 컴퓨터는 사람들이 학교에서 배우는 산술과 같은 방식으로 동작하는 산술을 반드시 제공해야 한다.” – 십진 산술 명세에서 발췌.

Decimal numbers can be represented exactly. In contrast, numbers like 1.1 and 2.2 do not have exact representations in binary floating point. End users typically would not expect 1.1 + 2.2 to display as 3.3000000000000003 as it does with binary floating point.

The exactness carries over into arithmetic. In decimal floating point, 0.1 + 0.1 + 0.1 - 0.3 is exactly equal to zero. In binary floating point, the result is 5.5511151231257827e-017. While near to zero, the differences prevent reliable equality testing and differences can accumulate. For this reason, decimal is preferred in accounting applications which have strict equality invariants.

The decimal module incorporates a notion of significant places so that 1.30 + 1.20 is 2.50. The trailing zero is kept to indicate significance. This is the customary presentation for monetary applications. For multiplication, the “schoolbook” approach uses all the figures in the multiplicands. For instance, 1.3 * 1.2 gives 1.56 while 1.30 * 1.20 gives 1.5600.

하드웨어 기반 이진 부동 소수점과는 달리, decimal 모듈은 사용자가 변경할 수 있는 정밀도(기본값은 28자리)를 가지며, 주어진 문제에 따라 필요한 만큼 커질 수 있습니다:

>>> from decimal import *
>>> getcontext().prec = 6
>>> Decimal(1) / Decimal(7)
Decimal('0.142857')
>>> getcontext().prec = 28
>>> Decimal(1) / Decimal(7)
Decimal('0.1428571428571428571428571429')

이진 및 십진 부동 소수점 모두 출판된 표준에 따라 구현됩니다. 내장 float 형이 기능의 적당한 부분만을 드러내지만, decimal 모듈은 표준의 모든 필수 부분을 노출합니다. 필요한 경우, 프로그래머는 자리 올림(rounding) 및 신호(signal) 처리를 완전히 제어할 수 있습니다. 여기에는 정확하지 않은 연산을 차단하기 위한 예외를 사용하여 정확한 산술을 강제하는 옵션이 포함됩니다.

decimal 모듈은 “편견 없이, (때로 고정 소수점 산술이라고도 불리는) 정확한 자리 올림 없는 십진 산술과 자리 올림 있는 부동 소수점 산술을 모두” 지원하도록 설계되었습니다. – 십진 산술 명세에서 발췌.

모듈 설계의 중심 개념은 세 가지입니다: 십진수, 산술을 위한 컨텍스트, 신호(signal).

A decimal number is immutable. It has a sign, coefficient digits, and an exponent. To preserve significance, the coefficient digits do not truncate trailing zeros. Decimals also include special values such as Infinity, -Infinity, and NaN. The standard also differentiates -0 from +0.

산술 컨텍스트는 정밀도, 자리 올림 규칙, 지수에 대한 제한, 연산 결과를 나타내는 플래그 및 신호가 예외로 처리될지를 결정하는 트랩 활성화기(trap enabler)를 지정하는 환경입니다. 자리 올림 옵션에는 ROUND_CEILING, ROUND_DOWN, ROUND_FLOOR, ROUND_HALF_DOWN, ROUND_HALF_EVEN, ROUND_HALF_UP, ROUND_UP 및 ROUND_05UP 가 있습니다.

신호는 계산 과정에서 발생하는 예외적인 조건의 그룹입니다. 응용 프로그램의 필요에 따라, 신호가 무시되거나, 정보로 간주하거나, 예외로 처리될 수 있습니다. decimal 모듈의 신호는 Clamped, InvalidOperation, DivisionByZero, Inexact, Rounded, Subnormal, Overflow, Underflow, FloatOperation 입니다.

각 신호에는 플래그와 트랩 활성화기가 있습니다. 신호와 만났을 때, 플래그가 1로 설정되고 트랩 활성화기가 1로 설정된 경우, 예외가 발생합니다. 플래그는 상태가 유지되므로(sticky) 계산을 감시하기 전에 재설정할 필요가 있습니다.

더 보기

IBM’s General Decimal Arithmetic Specification, The General Decimal Arithmetic Specification [https://speleotrove.com/decimal/decarith.html].

빠른 시작 자습서

decimal을 사용하는 일반적인 시작은 모듈을 임포트하고, getcontext() 로 현재 컨텍스트를 보고, 필요하다면 정밀도, 자리 올림 또는 활성화된 트랩에 대해 새 값을 설정하는 것입니다:

>>> from decimal import *
>>> getcontext()
Context(prec=28, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
        capitals=1, clamp=0, flags=[], traps=[Overflow, DivisionByZero,
        InvalidOperation])

>>> getcontext().prec = 7       # Set a new precision

Decimal instances can be constructed from integers, strings, floats, or tuples. Construction from an integer or a float performs an exact conversion of the value of that integer or float. Decimal numbers include special values such as NaN which stands for “Not a number”, positive and negative Infinity, and -0:

>>> getcontext().prec = 28
>>> Decimal(10)
Decimal('10')
>>> Decimal('3.14')
Decimal('3.14')
>>> Decimal(3.14)
Decimal('3.140000000000000124344978758017532527446746826171875')
>>> Decimal((0, (3, 1, 4), -2))
Decimal('3.14')
>>> Decimal(str(2.0 ** 0.5))
Decimal('1.4142135623730951')
>>> Decimal(2) ** Decimal('0.5')
Decimal('1.414213562373095048801688724')
>>> Decimal('NaN')
Decimal('NaN')
>>> Decimal('-Infinity')
Decimal('-Infinity')

FloatOperation 신호를 트랩 하는 경우, 실수로 생성자나 대소비교에서 Decimal 수와 실수(float)를 혼합하면 예외가 발생합니다:

>>> c = getcontext()
>>> c.traps[FloatOperation] = True
>>> Decimal(3.14)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.FloatOperation: [<class 'decimal.FloatOperation'>]
>>> Decimal('3.5') < 3.7
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.FloatOperation: [<class 'decimal.FloatOperation'>]
>>> Decimal('3.5') == 3.5
True

Added in version 3.3.

새로운 Decimal의 유효 숫자는 입력된 숫자의 개수에 의해서만 결정됩니다. 컨텍스트 정밀도 및 자리 올림은 오직 산술 연산 중에만 작용합니다.

>>> getcontext().prec = 6
>>> Decimal('3.0')
Decimal('3.0')
>>> Decimal('3.1415926535')
Decimal('3.1415926535')
>>> Decimal('3.1415926535') + Decimal('2.7182818285')
Decimal('5.85987')
>>> getcontext().rounding = ROUND_UP
>>> Decimal('3.1415926535') + Decimal('2.7182818285')
Decimal('5.85988')

C 버전의 내부 제한을 초과하면, Decimal 을 만들 때 InvalidOperation 를 일으킵니다:

>>> Decimal("1e9999999999999999999")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

버전 3.3에서 변경.

Decimals interact well with much of the rest of Python. Here is a small decimal floating-point flying circus:

>>> data = list(map(Decimal, '1.34 1.87 3.45 2.35 1.00 0.03 9.25'.split()))
>>> max(data)
Decimal('9.25')
>>> min(data)
Decimal('0.03')
>>> sorted(data)
[Decimal('0.03'), Decimal('1.00'), Decimal('1.34'), Decimal('1.87'),
 Decimal('2.35'), Decimal('3.45'), Decimal('9.25')]
>>> sum(data)
Decimal('19.29')
>>> a,b,c = data[:3]
>>> str(a)
'1.34'
>>> float(a)
1.34
>>> round(a, 1)
Decimal('1.3')
>>> int(a)
1
>>> a * 5
Decimal('6.70')
>>> a * b
Decimal('2.5058')
>>> c % a
Decimal('0.77')

그리고 Decimal에는 몇 가지 수학 함수도 있습니다:

>>> getcontext().prec = 28
>>> Decimal(2).sqrt()
Decimal('1.414213562373095048801688724')
>>> Decimal(1).exp()
Decimal('2.718281828459045235360287471')
>>> Decimal('10').ln()
Decimal('2.302585092994045684017991455')
>>> Decimal('10').log10()
Decimal('1')

The quantize() method rounds a number to a fixed exponent. This method is useful for monetary applications that often round results to a fixed number of places:

>>> Decimal('7.325').quantize(Decimal('.01'), rounding=ROUND_DOWN)
Decimal('7.32')
>>> Decimal('7.325').quantize(Decimal('1.'), rounding=ROUND_UP)
Decimal('8')

위에서 보듯이, getcontext() 함수는 현재 컨텍스트에 액세스하고 설정을 변경할 수 있게 합니다. 이 방법은 대부분 응용 프로그램의 요구를 충족시킵니다.

고급 작업을 위해, Context() 생성자를 사용하여 대체 컨텍스트를 만드는 것이 유용할 수 있습니다. 대체 컨텍스트를 활성화하려면, setcontext() 함수를 사용하십시오.

표준에 따라, decimal 모듈은 당장 사용할 수 있는 두 개의 표준 컨텍스트 BasicContext 와 ExtendedContext 를 제공합니다. 특히 전자는 많은 트랩이 활성화되어있어 디버깅에 유용합니다:

>>> myothercontext = Context(prec=60, rounding=ROUND_HALF_DOWN)
>>> setcontext(myothercontext)
>>> Decimal(1) / Decimal(7)
Decimal('0.142857142857142857142857142857142857142857142857142857142857')

>>> ExtendedContext
Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
        capitals=1, clamp=0, flags=[], traps=[])
>>> setcontext(ExtendedContext)
>>> Decimal(1) / Decimal(7)
Decimal('0.142857143')
>>> Decimal(42) / Decimal(0)
Decimal('Infinity')

>>> setcontext(BasicContext)
>>> Decimal(42) / Decimal(0)
Traceback (most recent call last):
  File "<pyshell#143>", line 1, in -toplevel-
    Decimal(42) / Decimal(0)
DivisionByZero: x / 0

Contexts also have signal flags for monitoring exceptional conditions encountered during computations. The flags remain set until explicitly cleared, so it is best to clear the flags before each set of monitored computations by using the clear_flags() method.

>>> setcontext(ExtendedContext)
>>> getcontext().clear_flags()
>>> Decimal(355) / Decimal(113)
Decimal('3.14159292')
>>> getcontext()
Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
        capitals=1, clamp=0, flags=[Inexact, Rounded], traps=[])

The flags entry shows that the rational approximation to pi was rounded (digits beyond the context precision were thrown away) and that the result is inexact (some of the discarded digits were non-zero).

Individual traps are set using the dictionary in the traps attribute of a context:

>>> setcontext(ExtendedContext)
>>> Decimal(1) / Decimal(0)
Decimal('Infinity')
>>> getcontext().traps[DivisionByZero] = 1
>>> Decimal(1) / Decimal(0)
Traceback (most recent call last):
  File "<pyshell#112>", line 1, in -toplevel-
    Decimal(1) / Decimal(0)
DivisionByZero: x / 0

대부분 프로그램은 프로그램 시작 시에 한 번만 현재 컨텍스트를 조정합니다. 그리고, 많은 응용 프로그램에서, 데이터는 루프 내에서 단일형변환으로 Decimal로 변환되어, 프로그램 대부분은 다른 파이썬 숫자 형과 별로 다르지 않게 데이터를 조작합니다.

Decimal 객체

class decimal.Decimal(value='0', context=None)

value 를 기반으로 새 Decimal 객체를 만듭니다.

value 는 정수, 문자열, 튜플, float 또는 다른 Decimal 객체일 수 있습니다. value 가 주어지지 않으면, Decimal('0') 을 반환합니다. value 가 문자열이면, 앞뒤의 공백 문자 및 밑줄이 제거된 후 십진수 문자열 문법에 맞아야 합니다:

sign           ::=  '+' | '-'
digit          ::=  '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'
indicator      ::=  'e' | 'E'
digits         ::=  digit [digit]...
decimal-part   ::=  digits '.' [digits] | ['.'] digits
exponent-part  ::=  indicator [sign] digits
infinity       ::=  'Infinity' | 'Inf'
nan            ::=  'NaN' [digits] | 'sNaN' [digits]
numeric-value  ::=  decimal-part [exponent-part] | infinity
numeric-string ::=  [sign] numeric-value | [sign] nan

위의 digit 가 나타나는 곳에는 다른 유니코드 십진수도 허용됩니다. 여기에는 다양한 다른 알파벳(예를 들어, 인도-아라비아와 데바나가리 숫자)의 십진수와 전각 숫자 '\uff10' 에서 '\uff19' 까지 포함됩니다.

If value is a tuple, it should have three components, a sign (0 for positive or 1 for negative), a tuple of digits, and an integer exponent. For example, Decimal((0, (1, 4, 1, 4), -3)) returns Decimal('1.414').

If value is a float, the binary floating-point value is losslessly converted to its exact decimal equivalent. This conversion can often require 53 or more digits of precision. For example, Decimal(float('1.1')) converts to Decimal('1.100000000000000088817841970012523233890533447265625').

context 정밀도는 저장되는 자릿수에 영향을 주지 않습니다. 저장되는 자릿수는 value 의 자릿수만으로 결정됩니다. 예를 들어 Decimal('3.00000') 은 컨텍스트 정밀도가 단지 3이라도 5개의 모든 0을 기록합니다.

The purpose of the context argument is determining what to do if value is a malformed string. If the context traps InvalidOperation, an exception is raised; otherwise, the constructor returns a new Decimal with the value of NaN.

일단 만들어지면, Decimal 객체는 불변입니다.

버전 3.2에서 변경: 생성자에 대한 인자는 이제 float 인스턴스가 될 수 있습니다.

버전 3.3에서 변경: float 인자는 FloatOperation 트랩이 설정되면 예외를 발생시킵니다. 기본적으로 트랩은 꺼져 있습니다.

버전 3.6에서 변경: 코드에서의 정수와 부동 소수점 리터럴과 마찬가지로, 밑줄로 무리 지을 수 있습니다.

Decimal floating-point objects share many properties with the other built-in numeric types such as float and int. All of the usual math operations and special methods apply. Likewise, decimal objects can be copied, pickled, printed, used as dictionary keys, used as set elements, compared, sorted, and coerced to another type (such as float or int).

Decimal 객체에 대한 산술과 정수 및 실수에 대한 산술에는 약간의 차이가 있습니다. Decimal 객체에 나머지 연산자 % 가 적용될 때, 결과의 부호는 제수의 부호가 아닌 피제수의 부호가 됩니다:

>>> (-7) % 4
1
>>> Decimal(-7) % Decimal(4)
Decimal('-3')

정수 나눗셈 연산자 // 의 동작 역시 비슷한 차이를 보입니다. 즉, 가장 가까운 정수로 내림하는 대신 실제 몫의 정수 부(0을 향해 자르기)를 돌려줍니다. 그래서 일반적인 항등식 x == (x // y) * y + x % y 를 유지합니다:

>>> -7 // 4
-2
>>> Decimal(-7) // Decimal(4)
Decimal('-1')

% 와 // 연산자는 명세에 설명된 대로 각각 remainder 와 divide-integer 연산을 구현합니다.

Decimal 객체는 일반적으로 산술 연산에서 float 나 fractions.Fraction 인스턴스와 결합 할 수 없습니다: 예를 들어, float 에 a Decimal을 더하려고 하면 TypeError 를 일으킵니다. 그러나, 파이썬의 비교 연산자를 사용하여 Decimal 인스턴스 x 와 다른 숫자 y 를 비교할 수 있습니다. 이렇게 해서 서로 다른 형의 숫자 간에 동등 비교를 할 때 혼란스러운 결과를 피합니다.

버전 3.2에서 변경: Decimal 인스턴스와 다른 숫자 형 사이의 혼합형 비교가 이제 완전히 지원됩니다.

In addition to the standard numeric properties, decimal floating-point objects also have a number of specialized methods:

adjusted()

최상위 숫자만 남을 때까지 계수의 가장 오른쪽 숫자들을 밀어내도록 조정된 지수를 반환합니다. Decimal('321e+5').adjusted() 는 7을 반환합니다. 소수점으로부터의 최상위 유효 숫자의 위치를 결정하는 데 사용됩니다.

as_integer_ratio()

주어진 Decimal 인스턴스를, 분모가 양수인 기약 분수로 나타내는 정수의 쌍 (n, d) 을 돌려줍니다:

>>> Decimal('-3.14').as_integer_ratio()
(-157, 50)

변환은 정확합니다. 무한대는 OverflowError를, NaN 은 ValueError를 일으킵니다.

Added in version 3.6.

as_tuple()

숫자의 네임드 튜플 표현을 반환합니다: DecimalTuple(sign, digits, exponent).

canonical()

인자의 규범적인 인코딩을 돌려줍니다. 현재 Decimal 인스턴스의 인코딩은 항상 규범적이므로, 이 연산은 인자를 변경하지 않고 반환합니다.

compare(other, context=None)

두 Decimal 인스턴스의 값을 비교합니다. compare() 는 Decimal 인스턴스를 반환하고, 피연산자 중 하나가 NaN이면 결과는 NaN입니다:

a or b is a NaN  ==> Decimal('NaN')
a < b            ==> Decimal('-1')
a == b           ==> Decimal('0')
a > b            ==> Decimal('1')

compare_signal(other, context=None)

이 연산은, 모든 NaN 이 신호를 준다는 것을 제외하면 compare() 메서드와 같습니다. 즉, 피연산자가 모두 신호를 주는 NaN이 아니면, 모든 조용한 NaN 피연산자가 마치 신호를 주는 NaN 인 것처럼 처리됩니다.

compare_total(other, context=None)

두 개의 피연산자를 숫자 값 대신 추상 표현을 사용하여 비교합니다. compare() 메서드와 비슷하지만, 결과는 Decimal 인스턴스에 대해 전 순서(total ordering)를 부여합니다. 같은 숫자 값을 갖지만 다른 표현의 두 Decimal 인스턴스는 이 순서에 의해 다른 것으로 비교됩니다:

>>> Decimal('12.0').compare_total(Decimal('12'))
Decimal('-1')

조용한 NaN과 신호를 주는 NaN도 전 순서에 포함됩니다. 이 함수의 결과는, 두 피연산자가 같은 표현을 가질 때 Decimal('0'), 첫 번째 피연산자가 전 순서에서 두 번째 피연산자보다 낮으면 Decimal('-1'), 첫 번째 피연산자가 전 순서에서 두 번째 피연산자보다 높으면 Decimal('1') 입니다. 전 순서에 대한 세부 사항은 명세를 참조하십시오.

이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다. 예외적으로, 두 번째 피연산자를 정확하게 변환할 수 없으면 C 버전은 InvalidOperation을 발생시킬 수 있습니다.

compare_total_mag(other, context=None)

compare_total()처럼 두 개의 피연산자를 숫자 값 대신 추상 표현을 사용하여 비교하지만, 각 피연산자의 부호를 무시합니다. x.compare_total_mag(y) 는 x.copy_abs().compare_total(y.copy_abs()) 와 동등합니다.

이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다. 예외적으로, 두 번째 피연산자를 정확하게 변환할 수 없으면 C 버전은 InvalidOperation을 발생시킬 수 있습니다.

conjugate()

그냥 self를 돌려줍니다. 이 메서드는 Decimal 명세를 준수하기 위한 것뿐입니다.

copy_abs()

인자의 절댓값을 반환합니다. 이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다.

copy_negate()

인자의 음의 부정을 돌려줍니다. 이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다.

copy_sign(other, context=None)

두 번째 피연산자의 부호와 같은 부호로 설정된 첫 번째 피연산자의 복사본을 반환합니다. 예를 들어:

>>> Decimal('2.3').copy_sign(Decimal('-1.5'))
Decimal('-2.3')

이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다. 예외적으로, 두 번째 피연산자를 정확하게 변환할 수 없으면 C 버전은 InvalidOperation을 발생시킬 수 있습니다.

exp(context=None)

주어진 숫자에 대한 (자연) 지수 함수 e**x 의 값을 반환합니다. 결과는 ROUND_HALF_EVEN 자리 올림 모드를 사용하여 올바르게 자리 올림 됩니다.

>>> Decimal(1).exp()
Decimal('2.718281828459045235360287471')
>>> Decimal(321).exp()
Decimal('2.561702493119680037517373933E+139')

classmethod from_float(f)

Alternative constructor that only accepts instances of float or int.

Note Decimal.from_float(0.1) is not the same as Decimal('0.1'). Since 0.1 is not exactly representable in binary floating point, the value is stored as the nearest representable value which is 0x1.999999999999ap-4. That equivalent value in decimal is 0.1000000000000000055511151231257827021181583404541015625.

참고

파이썬 3.2 이후부터는, Decimal 인스턴스를 float에서 직접 생성할 수 있습니다.

>>> Decimal.from_float(0.1)
Decimal('0.1000000000000000055511151231257827021181583404541015625')
>>> Decimal.from_float(float('nan'))
Decimal('NaN')
>>> Decimal.from_float(float('inf'))
Decimal('Infinity')
>>> Decimal.from_float(float('-inf'))
Decimal('-Infinity')

Added in version 3.1.

classmethod from_number(number)

Alternative constructor that only accepts instances of float, int or Decimal, but not strings or tuples.

>>> Decimal.from_number(314)
Decimal('314')
>>> Decimal.from_number(0.1)
Decimal('0.1000000000000000055511151231257827021181583404541015625')
>>> Decimal.from_number(Decimal('3.14'))
Decimal('3.14')

Added in version 3.14.

fma(other, third, context=None)

합성된 곱셈-덧셈(fused multiply-add). 중간값 self*other의 자리 올림 없이 self*other+third를 반환합니다.

>>> Decimal(2).fma(3, 5)
Decimal('11')

is_canonical()

인자가 규범적이면 True를 반환하고, 그렇지 않으면 False를 반환합니다. 현재 Decimal 인스턴스는 항상 규범적이므로 이 연산은 항상 True를 반환합니다.

is_finite()

인자가 유한 수이면 True를 반환하고, 인자가 무한대나 NaN 이면 False를 반환합니다.

is_infinite()

인자가 양이나 음의 무한대면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

is_nan()

인자가 (조용한 또는 신호를 주는) NaN이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

is_normal(context=None)

인자가 정상(normal) 유한 수이면 True를 반환합니다. 인자가 0, 비정상(subnormal), 무한대 또는 NaN 이면 False를 반환합니다.

is_qnan()

인자가 조용한 NaN이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

is_signed()

인자가 음의 부호를 가지면 True를 반환하고, 그렇지 않으면 False를 반환합니다. 0과 NaN 모두 부호를 가질 수 있다는 것에 유의하세요.

is_snan()

인자가 신호를 주는 NaN이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

is_subnormal(context=None)

인자가 비정상(subnormal)이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

is_zero()

인자가 (양 또는 음의) 0이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

ln(context=None)

피연산자의 자연로그(밑 e)를 반환합니다. 결과는 ROUND_HALF_EVEN 자리 올림 모드를 사용하여 올바르게 반올림됩니다.

log10(context=None)

피연산자의 상용로그를 반환합니다. 결과는 ROUND_HALF_EVEN 자리 올림 모드를 사용하여 올바르게 반올림됩니다.

logb(context=None)

0이 아닌 수의 경우, 피연산자의 조정된 지수를 Decimal 인스턴스로 반환합니다. 피연산자가 0이면 Decimal('-Infinity') 가 반환되고 DivisionByZero 플래그가 발생합니다. 피연산자가 무한대면 Decimal('Infinity') 가 반환됩니다.

logical_and(other, context=None)

logical_and() 는 두 개의 논리적 피연산자(논리적 피연산자를 보세요)를 취하는 논리적 연산입니다. 결과는 두 피연산자의 자릿수별 and 입니다.

logical_invert(context=None)

logical_invert() 는 논리적 연산입니다. 결과는 피연산자의 자릿수별 반전입니다.

logical_or(other, context=None)

logical_or() 는 두 개의 논리적 피연산자(논리적 피연산자를 보세요)를 취하는 논리적 연산입니다. 결과는 두 피연산자의 자릿수별 or 입니다.

logical_xor(other, context=None)

logical_xor()은 두 개의 논리적 피연산자(논리적 피연산자를 보세요)를 취하는 논리적 연산입니다. 결과는 두 피연산자의 자릿수별 배타적 or입니다.

max(other, context=None)

Like max(self, other) except that the context rounding rule is applied before returning and that NaN values are either signaled or ignored (depending on the context and whether they are signaling or quiet).

max_mag(other, context=None)

max()와 비슷하지만, 피연산자의 절댓값을 사용하여 비교가 이루어집니다.

min(other, context=None)

Like min(self, other) except that the context rounding rule is applied before returning and that NaN values are either signaled or ignored (depending on the context and whether they are signaling or quiet).

min_mag(other, context=None)

min()과 비슷하지만, 피연산자의 절댓값을 사용하여 비교가 이루어집니다.

next_minus(context=None)

주어진 피연산자보다 작고, 주어진 컨텍스트(또는 context가 주어지지 않으면 현재 스레드의 컨텍스트)에서 표현 가능한 가장 큰 수를 돌려줍니다.

next_plus(context=None)

주어진 피연산자보다 크고, 주어진 컨텍스트(또는 context가 주어지지 않으면 현재 스레드의 컨텍스트)에서 표현 가능한 가장 작은 수를 돌려줍니다.

next_toward(other, context=None)

두 피연산자가 같지 않으면, 두 번째 피연산자의 방향으로 첫 번째 피연산자에 가장 가까운 숫자를 반환합니다. 두 피연산자가 수치로 같으면, 첫 번째 피연산자의 복사본을 반환하는데, 부호를 두 번째 피연산자의 것으로 설정합니다.

normalize(context=None)

Used for producing canonical values of an equivalence class within either the current context or the specified context.

This has the same semantics as the unary plus operation, except that if the final result is finite it is reduced to its simplest form, with all trailing zeros removed and its sign preserved. That is, while the coefficient is non-zero and a multiple of ten the coefficient is divided by ten and the exponent is incremented by 1. Otherwise (the coefficient is zero) the exponent is set to 0. In all cases the sign is unchanged.

For example, Decimal('32.100') and Decimal('0.321000e+2') both normalize to the equivalent value Decimal('32.1').

Note that rounding is applied before reducing to simplest form.

In the latest versions of the specification, this operation is also known as reduce.

number_class(context=None)

피연산자의 클래스 를 설명하는 문자열을 반환합니다. 반환 값은 다음 10개의 문자열 중 하나입니다.

"-Infinity", 피연산자가 음의 무한대임을 나타냅니다.

"-Normal", 피연산자가 음의 정상 수임을 나타냅니다.

"-Subnormal", 피연산자가 음의 비정상 수임을 나타냅니다.

"-Zero", 피연산자가 음의 0임을 나타냅니다.

"+Zero", 피연산자가 양의 0임을 나타냅니다.

"+Subnormal", 피연산자가 양의 비정상 수임을 나타냅니다.

"+Normal", 피연산자가 양의 정상 수임을 나타냅니다.

"+Infinity", 피연산자가 양의 무한대임을 나타냅니다.

"NaN", 피연산자가 조용한 NaN(Not a Number)임을 나타냅니다.

"sNaN", 피연산자가 신호를 주는 NaN임을 나타냅니다.

quantize(exp, rounding=None, context=None)

자리 올림 후에 첫 번째 피연산자와 같고 두 번째 피연산자의 지수를 갖는 값을 반환합니다.

>>> Decimal('1.41421356').quantize(Decimal('1.000'))
Decimal('1.414')

다른 연산과 달리, quantize 연산 후의 계수의 길이가 정밀도보다 크면, InvalidOperation 신호를 줍니다. 이는, 에러 조건이 없으면, quantize 된 지수가 항상 오른쪽 피연산자의 지수와 같음을 보장합니다.

또한, 다른 연산과는 달리, 결과가 비정상(subnormal)이고 부정확한 경우조차도, quantize는 결코 Underflow 신호를 보내지 않습니다.

두 번째 피연산자의 지수가 첫 번째 피연산자의 지수보다 크면 자리 올림이 필요할 수 있습니다. 이 경우, 자리 올림 모드는 (주어지면) rounding 인자에 의해 결정됩니다. 그렇지 않으면 주어진 context 인자에 의해 결정됩니다; 두 인자 모두 주어지지 않으면, 현재 스레드의 컨텍스트의 자리 올림 모드가 사용됩니다.

An error is returned whenever the resulting exponent is greater than Emax or less than Etiny().

radix()

Decimal 클래스가 모든 산술을 수행하는 진수(기수)인 Decimal(10) 을 반환합니다. 명세와의 호환성을 위해 포함됩니다.

remainder_near(other, context=None)

self 를 other 로 나눈 나머지를 반환합니다. 이것은 나머지의 절댓값을 최소화하기 위해 나머지의 부호가 선택된다는 점에서 self % other 와 다릅니다. 좀 더 정확히 말하면, 반환 값은 self - n * other 인데, 여기서 n 은 self / other 의 정확한 값에 가장 가까운 정수이고, 두 개의 정수와의 거리가 같으면 짝수가 선택됩니다.

결과가 0이면 그 부호는 self 의 부호가 됩니다.

>>> Decimal(18).remainder_near(Decimal(10))
Decimal('-2')
>>> Decimal(25).remainder_near(Decimal(10))
Decimal('5')
>>> Decimal(35).remainder_near(Decimal(10))
Decimal('-5')

rotate(other, context=None)

첫 번째 피연산자의 계수를 두 번째 피연산자로 지정된 양만큼 회전한 결과를 반환합니다. 두 번째 피연산자는 -precision에서 precision 범위의 정수여야 합니다. 두 번째 피연산자의 절댓값은 회전할 자리의 수를 나타냅니다. 두 번째 피연산자가 양수면 왼쪽으로 회전합니다; 그렇지 않으면 오른쪽으로 회전합니다. 필요하면 정밀도에 맞추기 위해 첫 번째 피연산자의 계수에 0이 왼쪽에 채워집니다. 첫 번째 피연산자의 부호와 지수는 변경되지 않습니다.

same_quantum(other, context=None)

Test whether self and other have the same exponent or whether both are NaN.

이 연산은 컨텍스트의 영향을 받지 않고, 조용합니다: 어떤 플래그도 변경되지 않고, 어떤 자리 올림도 수행되지 않습니다. 예외적으로, 두 번째 피연산자를 정확하게 변환할 수 없으면 C 버전은 InvalidOperation을 발생시킬 수 있습니다.

scaleb(other, context=None)

첫 번째 피연산자의 지수를 두 번째 피연산자만큼 조정한 값을 반환합니다. 달리 표현하면, 첫 번째 피연산자에 10**other 를 곱한 값을 반환합니다. 두 번째 피연산자는 정수여야 합니다.

shift(other, context=None)

첫 번째 피연산자의 계수를 두 번째 피연산자로 지정된 양만큼 이동한 결과를 반환합니다. 두 번째 피연산자는 -precision에서 precision 범위의 정수여야 합니다. 두 번째 피연산자의 절댓값은 이동할 자리의 수를 나타냅니다. 두 번째 피연산자가 양수면 왼쪽으로 이동합니다; 그렇지 않으면 오른쪽으로 이동합니다. 이동으로 인해 계수에 들어오는 숫자는 0입니다. 첫 번째 피연산자의 부호와 지수는 변경되지 않습니다.

sqrt(context=None)

인자의 제곱근을 완전한 정밀도로 반환합니다.

to_eng_string(context=None)

문자열로 변환합니다. 지수가 필요하면 공학 표기법을 사용합니다.

공학 표기법의 지수는 3의 배수입니다. 이렇게 하면 소수점 왼쪽에 최대 3자리를 남기게 되고, 하나나 두 개의 후행 0을 추가해야 할 수 있습니다.

예를 들어, 이 메서드는 Decimal('123E+1') 을 Decimal('1.23E+3') 으로 변환합니다.

to_integral(rounding=None, context=None)

to_integral_value() 메서드와 같습니다. to_integral 이름은 이전 버전과의 호환성을 위해 유지되었습니다.

to_integral_exact(rounding=None, context=None)

Inexact 나 Rounded 신호를 주면서 가장 가까운 정수로 자리 올림 합니다. 자리 올림 모드는 (주어지면) rounding 매개 변수에 의해, 그렇지 않으면 그렇지 않으면 context 에 의해 결정됩니다. 두 매개 변수 모두 지정되지 않으면, 현재 컨텍스트의 자리 올림 모드가 사용됩니다.

to_integral_value(rounding=None, context=None)

Inexact 나 Rounded 신호를 주지 않고 가장 가까운 정수로 자리 올림 합니다. 주어지면, rounding 을 적용합니다; 그렇지 않으면, 제공된 context 나 현재 컨텍스트의 자리 올림 방법을 사용합니다.

Decimal numbers can be rounded using the round() function:

round(number)

round(number, ndigits)

If ndigits is not given or None, returns the nearest int to number, rounding ties to even, and ignoring the rounding mode of the Decimal context. Raises OverflowError if number is an infinity or ValueError if it is a (quiet or signaling) NaN.

If ndigits is an int, the context’s rounding mode is respected and a Decimal representing number rounded to the nearest multiple of Decimal('1E-ndigits') is returned; in this case, round(number, ndigits) is equivalent to self.quantize(Decimal('1E-ndigits')). Returns Decimal('NaN') if number is a quiet NaN. Raises InvalidOperation if number is an infinity, a signaling NaN, or if the length of the coefficient after the quantize operation would be greater than the current context’s precision. In other words, for the non-corner cases:

if ndigits is positive, return number rounded to ndigits decimal places;

if ndigits is zero, return number rounded to the nearest integer;

if ndigits is negative, return number rounded to the nearest multiple of 10**abs(ndigits).

For example:

>>> from decimal import Decimal, getcontext, ROUND_DOWN
>>> getcontext().rounding = ROUND_DOWN
>>> round(Decimal('3.75'))     # context rounding ignored
4
>>> round(Decimal('3.5'))      # round-ties-to-even
4
>>> round(Decimal('3.75'), 0)  # uses the context rounding
Decimal('3')
>>> round(Decimal('3.75'), 1)
Decimal('3.7')
>>> round(Decimal('3.75'), -1)
Decimal('0E+1')

논리적 피연산자

The logical_and(), logical_invert(), logical_or(), and logical_xor() methods expect their arguments to be logical operands. A logical operand is a Decimal instance whose exponent and sign are both zero, and whose digits are all either 0 or 1.

Context 객체

컨텍스트는 산술 연산을 위한 환경입니다. 정밀도를 제어하고, 자리 올림 규칙을 설정하며, 어떤 신호가 예외로 처리되는지 결정하고, 지수의 범위를 제한합니다.

각 스레드는 자신만의 현재 컨텍스트를 가지는데, getcontext() 와 setcontext() 함수를 사용하여 액세스하거나 변경합니다:

decimal.getcontext()

활성 스레드의 현재 컨텍스트를 돌려줍니다.

decimal.setcontext(c)

활성 스레드의 현재 컨텍스트를 c 로 설정합니다.

또한 with 문과 localcontext() 함수를 사용하여 활성 컨텍스트를 일시적으로 변경할 수 있습니다.

decimal.localcontext(ctx=None, **kwargs)

Return a context manager that will set the current context for the active thread to a copy of ctx on entry to the with-statement and restore the previous context when exiting the with-statement. If no context is specified, a copy of the current context is used. The kwargs argument is used to set the attributes of the new context.

예를 들어, 다음 코드는 현재 십진 정밀도를 42자리로 설정하고, 계산을 수행한 다음, 이전 컨텍스트를 자동으로 복원합니다:

from decimal import localcontext

with localcontext() as ctx:
    ctx.prec = 42   # Perform a high precision calculation
    s = calculate_something()
s = +s  # Round the final result back to the default precision

Using keyword arguments, the code would be the following:

from decimal import localcontext

with localcontext(prec=42) as ctx:
    s = calculate_something()
s = +s

Raises TypeError if kwargs supplies an attribute that Context doesn’t support. Raises either TypeError or ValueError if kwargs supplies an invalid value for an attribute.

버전 3.11에서 변경: localcontext() now supports setting context attributes through the use of keyword arguments.

아래에 설명된 Context 생성자를 사용하여 새로운 컨텍스트를 만들 수도 있습니다. 또한, 이 모듈은 세 가지 미리 만들어진 컨텍스트를 제공합니다:

class decimal.BasicContext

이것은 일반 십진 산술 명세에서 정의된 표준 컨텍스트입니다. 정밀도는 9로 설정됩니다. 자리 올림은 ROUND_HALF_UP으로 설정됩니다. 모든 플래그가 지워집니다. 모든 트랩은 Inexact, Rounded, Subnormal을 제외하고는 활성화됩니다 (예외로 처리됩니다).

많은 트랩이 활성화되었으므로, 이 컨텍스트는 디버깅에 유용합니다.

class decimal.ExtendedContext

이것은 일반 십진 산술 명세에서 정의된 표준 컨텍스트입니다. 정밀도는 9로 설정됩니다. 자리 올림은 ROUND_HALF_EVEN으로 설정됩니다. 모든 플래그가 지워집니다. 아무 트랩도 활성화되지 않습니다 (그래서 계산 중에 예외가 발생하지 않습니다).

Because the traps are disabled, this context is useful for applications that prefer to have result value of NaN or Infinity instead of raising exceptions. This allows an application to complete a run in the presence of conditions that would otherwise halt the program.

class decimal.DefaultContext

이 컨텍스트는 새로운 컨텍스트의 프로토타입으로 Context 생성자에 의해 사용됩니다. 필드(가령 정밀도)를 변경하면 Context 생성자에 의해 생성된 새로운 컨텍스트에 대한 기본값을 변경하는 효과가 있습니다.

이 컨텍스트는 다중 스레드 환경에서 가장 유용합니다. 스레드가 시작되기 전에 필드 중 하나를 변경하면 시스템 전체의 기본값을 설정하는 효과가 있습니다. 스레드가 시작된 후에 필드를 변경하는 것은. 스레드 동기화를 통해 경쟁 조건을 방지해야 하므로 권장되지 않습니다.

단일 스레드 환경에서는, 이 컨텍스트를 아예 사용하지 않는 것이 좋습니다. 대신, 아래에 설명된 대로 명시적으로 컨텍스트를 만드십시오.

The default values are Context.prec=28, Context.rounding=ROUND_HALF_EVEN, and enabled traps for Overflow, InvalidOperation, and DivisionByZero.

3개의 제공된 컨텍스트 외에도, 새로운 컨텍스트를 Context 생성자를 사용하여 만들 수 있습니다.

class decimal.Context(prec=None, rounding=None, Emin=None, Emax=None, capitals=None, clamp=None, flags=None, traps=None)

새로운 컨텍스트를 만듭니다. 필드가 지정되지 않았거나 None 이면, 기본값은 DefaultContext 에서 복사됩니다. flags 필드가 지정되지 않았거나 None 이면, 모든 플래그가 지워집니다.

prec is an integer in the range [1, MAX_PREC] that sets the precision for arithmetic operations in the context.

rounding 옵션은 자리 올림 모드 섹션에 나열된 상수 중 하나입니다.

traps 과 flags 필드는 설정할 신호를 나열합니다. 일반적으로, 새 컨텍스트는 트랩만 설정하고 플래그는 지워진 채로 두어야 합니다.

The Emin and Emax fields are integers specifying the outer limits allowable for exponents. Emin must be in the range [MIN_EMIN, 0], Emax in the range [0, MAX_EMAX].

The capitals field is either 0 or 1 (the default). If set to 1, exponents are printed with a capital E; otherwise, a lowercase e is used: Decimal('6.02e+23').

The clamp field is either 0 (the default) or 1. If set to 1, the exponent e of a Decimal instance representable in this context is strictly limited to the range Emin - prec + 1 <= e <= Emax - prec + 1. If clamp is 0 then a weaker condition holds: the adjusted exponent of the Decimal instance is at most Emax. When clamp is 1, a large normal number will, where possible, have its exponent reduced and a corresponding number of zeros added to its coefficient, in order to fit the exponent constraints; this preserves the value of the number but loses information about significant trailing zeros. For example:

>>> Context(prec=6, Emax=999, clamp=1).create_decimal('1.23e999')
Decimal('1.23000E+999')

A clamp value of 1 allows compatibility with the fixed-width decimal interchange formats specified in IEEE 754.

The Context class defines several general purpose methods as well as a large number of methods for doing arithmetic directly in a given context. In addition, for each of the Decimal methods described above (with the exception of the adjusted() and as_tuple() methods) there is a corresponding Context method. For example, for a Context instance C and Decimal instance x, C.exp(x) is equivalent to x.exp(context=C). Each Context method accepts a Python integer (an instance of int) anywhere that a Decimal instance is accepted.

clear_flags()

Resets all of the flags to 0.

clear_traps()

Resets all of the traps to 0.

Added in version 3.3.

copy()

컨텍스트의 복사본을 돌려줍니다.

copy_decimal(num)

Decimal 인스턴스 num의 복사본을 반환합니다.

create_decimal(num)

self 를 컨텍스트로 사용해서, num 으로 새 Decimal 인스턴스를 만듭니다. Decimal 생성자와 달리, 컨텍스트 정밀도, 자리 올림 방법, 플래그 및 트랩이 변환에 적용됩니다.

이는 상수가 보통 응용 프로그램에 필요한 것보다 더 큰 정밀도로 제공되기 때문에 유용합니다. 또 다른 이점은 자리 올림이 현재 정밀도를 초과하는 자릿수로 인한 의도하지 않은 결과를 즉시 제거한다는 것입니다. 다음 예제에서, 자리 올림 되지 않은 입력을 사용한다는 것은 합계에 0을 추가하면 결과가 달라질 수 있음을 의미합니다.:

>>> getcontext().prec = 3
>>> Decimal('3.4445') + Decimal('1.0023')
Decimal('4.45')
>>> Decimal('3.4445') + Decimal(0) + Decimal('1.0023')
Decimal('4.44')

이 메서드는 IBM 명세의 to-number 연산을 구현합니다. 인자가 문자열이면, 선행 또는 후행 공백이나 밑줄이 허용되지 않습니다.

create_decimal_from_float(f)

float f 로 새 Decimal 인스턴스를 만들지만, self 를 컨텍스트로 사용하여 자리 올림 합니다. Decimal.from_float() 클래스 메서드와는 달리, 컨텍스트 정밀도, 자리 올림 방법, 플래그 및 트랩이 변환에 적용됩니다.

>>> context = Context(prec=5, rounding=ROUND_DOWN)
>>> context.create_decimal_from_float(math.pi)
Decimal('3.1415')
>>> context = Context(prec=5, traps=[Inexact])
>>> context.create_decimal_from_float(math.pi)
Traceback (most recent call last):
    ...
decimal.Inexact: None

Added in version 3.1.

Etiny()

비정상 결과에 대한 최소 지수 값인 Emin - prec + 1 과 같은 값을 반환합니다. 언더 플로우가 발생하면, 지수는 Etiny 로 설정됩니다.

Etop()

Emax - prec + 1 과 같은 값을 반환합니다.

십진수로 작업하는 일반적인 접근법은 Decimal 인스턴스를 생성한 다음 활성 스레드의 현재 컨텍스트 내에서 진행되는 산술 연산을 적용하는 것입니다. 다른 방법은 특정 컨텍스트 내에서 계산하기 위해 컨텍스트 메서드를 사용하는 것입니다. 메서드는 Decimal 클래스의 메서드와 비슷하며 여기에서는 간단히 설명합니다.

abs(x)

x 의 절댓값을 돌려줍니다.

add(x, y)

x 와 y 의 합을 돌려줍니다.

canonical(x)

같은 Decimal 객체 x 를 반환합니다.

compare(x, y)

x 와 y 를 수치로 비교합니다.

compare_signal(x, y)

두 피연산자의 값을 수치로 비교합니다.

compare_total(x, y)

추상 표현을 사용하여 두 피연산자를 비교합니다.

compare_total_mag(x, y)

부호를 무시하고, 추상 표현을 사용하여 두 피연산자를 비교합니다.

copy_abs(x)

부호가 0으로 설정되어있는 x 의 복사본을 돌려줍니다.

copy_negate(x)

부호가 반전된 x 복사본을 반환합니다.

copy_sign(x, y)

y 에서 x 로 부호를 복사합니다.

divide(x, y)

x 를 y 로 나눈 값을 반환합니다.

divide_int(x, y)

x 를 y 로 나눈 후 정수로 잘라낸 값을 반환합니다.

divmod(x, y)

두 숫자를 나누고 결과의 정수 부분을 반환합니다.

exp(x)

Returns e ** x.

fma(x, y, z)

x 에 y 를 곱한 후 z 를 더한 값을 반환합니다.

is_canonical(x)

x 가 규범적일 경우 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_finite(x)

x 가 유한이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_infinite(x)

x 가 무한대면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_nan(x)

x 가 qNaN 이나 sNaN 이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_normal(x)

x 가 정상 수면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_qnan(x)

x 가 조용한 NaN이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_signed(x)

x 가 음수면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_snan(x)

x 가 신호를 주는 NaN 이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_subnormal(x)

x 가 비정상이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

is_zero(x)

x 가 0이면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

ln(x)

x 의 자연로그(밑 e)를 반환합니다.

log10(x)

x 의 상용로그를 반환합니다.

logb(x)

피연산자의 최상위 유효 숫자의 크기의 지수를 반환합니다.

logical_and(x, y)

각 피연산자의 자릿수별로 논리적 연산 and 를 적용합니다.

logical_invert(x)

x 의 모든 자릿수를 반전합니다.

logical_or(x, y)

각 피연산자의 자릿수별로 논리적 연산 or 를 적용합니다.

logical_xor(x, y)

각 피연산자의 자릿수별로 논리적 연산 xor 를 적용합니다.

max(x, y)

두 값을 수치로 비교해, 최댓값을 돌려줍니다.

max_mag(x, y)

부호를 무시하고 값을 수치로 비교합니다.

min(x, y)

두 값을 수치로 비교해, 최솟값을 돌려줍니다.

min_mag(x, y)

부호를 무시하고 값을 수치로 비교합니다.

minus(x)

minus는 파이썬에서 단항 접두사 빼기 연산자에 해당합니다.

multiply(x, y)

x 와 y 의 곱을 반환합니다.

next_minus(x)

x 보다 작고 표현 가능한 가장 큰 수를 반환합니다.

next_plus(x)

x 보다 크고 표현 가능한 가장 작은 수를 반환합니다.

next_toward(x, y)

y 방향으로 x 에 가장 가까운 숫자를 반환합니다.

normalize(x)

x 를 가장 간단한 형태로 환원합니다.

number_class(x)

x 의 클래스를 가리키는 문자열을 돌려줍니다.

plus(x)

plus는 파이썬에서 단항 접두사 더하기 연산자에 해당합니다. 이 연산은 컨텍스트 정밀도와 자리 올림을 적용하므로 항등 연산이 아닙니다.

power(x, y, modulo=None)

x 의 y 거듭제곱을 돌려줍니다. 주어지면 modulo 모듈로로 환원합니다.

With two arguments, compute x**y. If x is negative then y must be integral. The result will be inexact unless y is integral and the result is finite and can be expressed exactly in ‘precision’ digits. The rounding mode of the context is used. Results are always correctly rounded in the Python version.

Decimal(0) ** Decimal(0)은 InvalidOperation이 되며, InvalidOperation가 트랩 되지 않으면, Decimal('NaN')이 됩니다.

버전 3.3에서 변경: The C module computes power() in terms of the correctly rounded exp() and ln() functions. The result is well-defined but only “almost always correctly rounded”.

세 인자로는 (x**y) % modulo 를 계산합니다. 세 인자 형식의 경우, 인자에 다음과 같은 제한이 있습니다:

세 인자는 모두 정수여야 합니다.

y 는 음수가 아니어야 합니다.

x 나 y 중 적어도 하나는 0이 아니어야 합니다

modulo 는 0이 아니고 최대 ‘precision’ 자릿수를 가져야 합니다

Context.power(x, y, modulo) 의 결괏값은 무한 정밀도로 (x**y) % modulo 를 계산할 때 얻을 수 있는 값과 같지만, 더 효율적으로 계산됩니다. 결과의 지수는 x, y 및 modulo 의 지수와 관계없이 0입니다. 결과는 항상 정확합니다.

quantize(x, y)

y 의 지수를 가지는 (자리 올림 된) x 와 같은 값을 반환합니다.

radix()

Decimal이기 때문에 단지 10을 반환합니다, :)

remainder(x, y)

정수 나눗셈의 나머지를 반환합니다.

결과가 0이 아닐 때, 결과의 부호는 원래의 피제수와 같습니다.

remainder_near(x, y)

x - y * n 을 반환하는데, n 은 x / y 의 정확한 값에 가장 가까운 정수입니다 (결과가 0이면 그 부호는 x 의 부호가 됩니다).

rotate(x, y)

x 를 y 번 회전한 복사본을 반환합니다.

same_quantum(x, y)

두 피연산자의 지수가 같으면 True를 반환합니다.

scaleb(x, y)

첫 번째 피연산자의 지수에 두 번째 값을 더해서 반환합니다.

shift(x, y)

x 를 y 번 이동한 복사본을 반환합니다.

sqrt(x)

음이 아닌 수의 제곱근을 컨텍스트의 정밀도로 반환합니다.

subtract(x, y)

x 와 y 의 차를 돌려줍니다.

to_eng_string(x)

문자열로 변환합니다. 지수가 필요하면 공학 표기법을 사용합니다.

공학 표기법의 지수는 3의 배수입니다. 이렇게 하면 소수점 왼쪽에 최대 3자리를 남기게 되고, 하나나 두 개의 후행 0을 추가해야 할 수 있습니다.

to_integral_exact(x)

정수로 자리 올림 합니다.

to_sci_string(x)

과학 표기법을 사용하여 숫자를 문자열로 변환합니다.

상수

이 절의 상수는 C 모듈에서만 의미가 있습니다. 호환성을 위해 순수 파이썬 버전에도 포함되어 있습니다.

32-비트

64-비트

decimal.MAX_PREC

425000000

999999999999999999

decimal.MAX_EMAX

425000000

999999999999999999

decimal.MIN_EMIN

-425000000

-999999999999999999

decimal.MIN_ETINY

-849999999

-1999999999999999997

decimal.HAVE_THREADS

값은 True입니다. 이제 파이썬에는 항상 스레드가 있기 때문에, 폐지되었습니다.

버전 3.9부터 폐지됨.

decimal.HAVE_CONTEXTVAR

The default value is True. If Python is configured using the --without-decimal-contextvar option, the C version uses a thread-local rather than a coroutine-local context and the value is False. This is slightly faster in some nested context scenarios.

Added in version 3.8.3.

자리 올림 모드

decimal.ROUND_CEILING

Round towards Infinity.

decimal.ROUND_DOWN

0을 향해 자리 올림 합니다.

decimal.ROUND_FLOOR

Round towards -Infinity.

decimal.ROUND_HALF_DOWN

가장 가까운 값으로 반올림하고, 동률이면 0에서 가까운 것을 선택합니다.

decimal.ROUND_HALF_EVEN

가장 가까운 값으로 반올림하고, 동률이면 짝수를 선택합니다.

decimal.ROUND_HALF_UP

가장 가까운 값으로 반올림하고, 동률이면 0에서 먼 것을 선택합니다.

decimal.ROUND_UP

0에서 먼 쪽으로 자리 올림 합니다.

decimal.ROUND_05UP

0을 향해 자리 올림 했을 때 마지막 숫자가 0이나 5면 0에서 먼 쪽으로 자리 올림 합니다. 그렇지 않으면 0을 향해 자리 올림 합니다.

신호

신호는 계산 중 발생하는 조건을 나타냅니다. 각각은 하나의 컨텍스트 플래그와 하나의 컨텍스트 트랩 활성화기에 대응합니다.

컨텍스트 플래그는 조건이 발생할 때마다 설정됩니다. 계산 후에, 플래그는 정보를 얻기 위한 목적으로 확인될 수 있습니다 (예를 들어, 계산이 정확한지를 판별하기 위해). 플래그를 확인한 후 다음 계산을 시작하기 전에 모든 플래그를 지우십시오.

컨텍스트의 트랩 활성화기가 신호에 대해 설정되면, 조건은 파이썬 예외를 일으킵니다. 예를 들어, DivisionByZero 트랩이 설정되면, 이 조건을 만날 때 DivisionByZero 예외가 발생합니다.

class decimal.Clamped

표현 제약 조건에 맞도록 지수를 변경했습니다.

Typically, clamping occurs when an exponent falls outside the context’s Emin and Emax limits. If possible, the exponent is reduced to fit by adding zeros to the coefficient.

class decimal.DecimalException

다른 신호의 베이스 클래스이고 ArithmeticError 의 서브 클래스입니다.

class decimal.DivisionByZero

무한대가 아닌 숫자를 0으로 나눴다는 신호를 줍니다.

Can occur with division, modulo division, or when raising a number to a negative power. If this signal is not trapped, returns Infinity or -Infinity with the sign determined by the inputs to the calculation.

class decimal.Inexact

자리 올림이 발생했고 결과가 정확하지 않음을 나타냅니다.

자리 올림 도중 0이 아닌 숫자가 삭제된 경우 신호를 줍니다. 자리 올림 된 결과가 반환됩니다. 신호 플래그나 트랩은 결과가 정확하지 않을 때를 감지하는 데 사용됩니다.

class decimal.InvalidOperation

유효하지 않은 연산이 수행되었습니다.

Indicates that an operation was requested that does not make sense. If not trapped, returns NaN. Possible causes include:

Infinity - Infinity
0 * Infinity
Infinity / Infinity
x % 0
Infinity % x
sqrt(-x) and x > 0
0 ** 0
x ** (non-integer)
x ** Infinity

class decimal.Overflow

수치적 오버플로.

Indicates the exponent is larger than Context.Emax after rounding has occurred. If not trapped, the result depends on the rounding mode, either pulling inward to the largest representable finite number or rounding outward to Infinity. In either case, Inexact and Rounded are also signaled.

class decimal.Rounded

정보가 손실되지는 않았지만 자리 올림이 발생했습니다.

Signaled whenever rounding discards digits; even if those digits are zero (such as rounding 5.00 to 5.0). If not trapped, returns the result unchanged. This signal is used to detect loss of significant digits.

class decimal.Subnormal

Exponent was lower than Emin prior to rounding.

연산 결과가 비정상(지수가 너무 작음)일 때 발생합니다. 트랩 되지 않으면, 결과를 그대로 반환합니다.

class decimal.Underflow

결과가 0으로 자리 올림 되는 수치적 언더플로.

자리 올림에 의해 비정상 결과가 0으로 밀릴 때 발생합니다. Inexact와 Subnormal 신호도 줍니다.

class decimal.FloatOperation

float와 Decimal을 혼합하는 데 더 엄격한 의미를 사용합니다.

신호가 트랩되지 않으면 (기본값), Decimal 생성자, create_decimal() 및 모든 비교 연산자에서 float와 Decimal을 혼합 할 수 있습니다. 변환과 비교 모두 정확합니다. 복합 연산의 발생은 컨텍스트 플래그에 FloatOperation 을 설정하여 조용히 기록됩니다. from_float() 나 create_decimal_from_float() 를 사용한 명시적 변환은 플래그를 설정하지 않습니다.

그렇지 않으면 (신호가 트랩되면), 같음 비교와 명시적 변환만 조용히 수행됩니다. 다른 모든 혼합된 연산은 FloatOperation 을 발생시킵니다.

다음 표는 신호의 계층 구조를 요약한 것입니다:

exceptions.ArithmeticError(exceptions.Exception)
    DecimalException
        Clamped
        DivisionByZero(DecimalException, exceptions.ZeroDivisionError)
        Inexact
            Overflow(Inexact, Rounded)
            Underflow(Inexact, Rounded, Subnormal)
        InvalidOperation
        Rounded
        Subnormal
        FloatOperation(DecimalException, exceptions.TypeError)

Floating-Point Notes

증가시킨 정밀도로 자리 올림 오차 줄이기

The use of decimal floating point eliminates decimal representation error (making it possible to represent 0.1 exactly); however, some operations can still incur round-off error when non-zero digits exceed the fixed precision.

The effects of round-off error can be amplified by the addition or subtraction of nearly offsetting quantities resulting in loss of significance. Knuth provides two instructive examples where rounded floating-point arithmetic with insufficient precision causes the breakdown of the associative and distributive properties of addition:

# Examples from Seminumerical Algorithms, Section 4.2.2.
>>> from decimal import Decimal, getcontext
>>> getcontext().prec = 8

>>> u, v, w = Decimal(11111113), Decimal(-11111111), Decimal('7.51111111')
>>> (u + v) + w
Decimal('9.5111111')
>>> u + (v + w)
Decimal('10')

>>> u, v, w = Decimal(20000), Decimal(-6), Decimal('6.0000003')
>>> (u*v) + (u*w)
Decimal('0.01')
>>> u * (v+w)
Decimal('0.0060000')

decimal 모듈은 유효숫자의 손실을 피할 수 있을 만큼 정밀도를 확장함으로써 항등 관계를 복구할 수 있게 합니다 :

>>> getcontext().prec = 20
>>> u, v, w = Decimal(11111113), Decimal(-11111111), Decimal('7.51111111')
>>> (u + v) + w
Decimal('9.51111111')
>>> u + (v + w)
Decimal('9.51111111')
>>>
>>> u, v, w = Decimal(20000), Decimal(-6), Decimal('6.0000003')
>>> (u*v) + (u*w)
Decimal('0.0060000')
>>> u * (v+w)
Decimal('0.0060000')

특수 값

The number system for the decimal module provides special values including NaN, sNaN, -Infinity, Infinity, and two zeros, +0 and -0.

무한대는 다음과 같이 직접 생성될 수 있습니다: Decimal('Infinity'). 또한, DivisionByZero 신호가 트랩 되지 않을 때 0으로 나눠서 발생할 수 있습니다. 마찬가지로, Overflow 신호가 트랩 되지 않을 때, 무한대는 표현 가능한 가장 큰 수의 한계를 넘어서 자리 올림 된 결과가 될 수 있습니다.

무한대는 부호가 있고 (아핀) 산술 연산에 사용될 수 있는데, 매우 크고 불확정적(indeterminate)인 숫자로 취급됩니다. 예를 들어, 무한대에 상수를 더하면 또 다른 무한대를 줍니다.

Some operations are indeterminate and return NaN, or if the InvalidOperation signal is trapped, raise an exception. For example, 0/0 returns NaN which means “not a number”. This variety of NaN is quiet and, once created, will flow through other computations always resulting in another NaN. This behavior can be useful for a series of computations that occasionally have missing inputs — it allows the calculation to proceed while flagging specific results as invalid.

A variant is sNaN which signals rather than remaining quiet after every operation. This is a useful return value when an invalid result needs to interrupt a calculation for special handling.

The behavior of Python’s comparison operators can be a little surprising where a NaN is involved. A test for equality where one of the operands is a quiet or signaling NaN always returns False (even when doing Decimal('NaN')==Decimal('NaN')), while a test for inequality always returns True. An attempt to compare two Decimals using any of the <, <=, > or >= operators will raise the InvalidOperation signal if either operand is a NaN, and return False if this signal is not trapped. Note that the General Decimal Arithmetic specification does not specify the behavior of direct comparisons; these rules for comparisons involving a NaN were taken from the IEEE 854 standard (see Table 3 in section 5.7). To ensure strict standards-compliance, use the compare() and compare_signal() methods instead.

부호 있는 0은 언더플로 하는 계산의 결과일 수 있습니다. 계산을 더 정밀하게 수행한다면 얻게 될 결과의 기호를 유지합니다. 크기가 0이기 때문에, 양과 음의 0은 같다고 취급되며 부호는 정보 용입니다.

In addition to the two signed zeros which are distinct yet equal, there are various representations of zero with differing precisions yet equivalent in value. This takes a bit of getting used to. For an eye accustomed to normalized floating-point representations, it is not immediately obvious that the following calculation returns a value equal to zero:

>>> 1 / Decimal('Infinity')
Decimal('0E-1000026')

스레드로 작업하기

getcontext() 함수는 스레드마다 다른 Context 객체에 접근합니다. 별도의 스레드 컨텍스트를 갖는다는 것은 스레드가 다른 스레드를 방해하지 않고 변경할 수 있음을 의미합니다 (가령 getcontext().prec=10).

마찬가지로, setcontext() 함수는 자동으로 대상을 현재 스레드에 할당합니다.

setcontext() 가 getcontext() 전에 호출되지 않았다면, getcontext() 는 현재 스레드에서 사용할 새로운 컨텍스트를 자동으로 생성합니다.

새 컨텍스트는 DefaultContext 라는 프로토타입 컨텍스트에서 복사됩니다. 각 스레드가 응용 프로그램 전체에서 같은 값을 사용하도록 기본값을 제어하려면, DefaultContext 객체를 직접 수정하십시오. getcontext() 를 호출하는 스레드 사이에 경쟁 조건이 없도록, 어떤 스레드가 시작되기 전에 수행되어야 합니다. 예를 들면:

# Set applicationwide defaults for all threads about to be launched
DefaultContext.prec = 12
DefaultContext.rounding = ROUND_DOWN
DefaultContext.traps = ExtendedContext.traps.copy()
DefaultContext.traps[InvalidOperation] = 1
setcontext(DefaultContext)

# Afterwards, the threads can be started
t1.start()
t2.start()
t3.start()
 . . .

조리법

다음은 유틸리티 함수로 사용되고 Decimal 클래스로 작업하는 방법을 보여주는 몇 가지 조리법입니다:

def moneyfmt(value, places=2, curr='', sep=',', dp='.',
             pos='', neg='-', trailneg=''):
    """Convert Decimal to a money formatted string.

    places:  required number of places after the decimal point
    curr:    optional currency symbol before the sign (may be blank)
    sep:     optional grouping separator (comma, period, space, or blank)
    dp:      decimal point indicator (comma or period)
             only specify as blank when places is zero
    pos:     optional sign for positive numbers: '+', space or blank
    neg:     optional sign for negative numbers: '-', '(', space or blank
    trailneg:optional trailing minus indicator:  '-', ')', space or blank

    >>> d = Decimal('-1234567.8901')
    >>> moneyfmt(d, curr='$')
    '-$1,234,567.89'
    >>> moneyfmt(d, places=0, sep='.', dp='', neg='', trailneg='-')
    '1.234.568-'
    >>> moneyfmt(d, curr='$', neg='(', trailneg=')')
    '($1,234,567.89)'
    >>> moneyfmt(Decimal(123456789), sep=' ')
    '123 456 789.00'
    >>> moneyfmt(Decimal('-0.02'), neg='<', trailneg='>')
    '<0.02>'

    """
    q = Decimal(10) ** -places      # 2 places --> '0.01'
    sign, digits, exp = value.quantize(q).as_tuple()
    result = []
    digits = list(map(str, digits))
    build, next = result.append, digits.pop
    if sign:
        build(trailneg)
    for i in range(places):
        build(next() if digits else '0')
    if places:
        build(dp)
    if not digits:
        build('0')
    i = 0
    while digits:
        build(next())
        i += 1
        if i == 3 and digits:
            i = 0
            build(sep)
    build(curr)
    build(neg if sign else pos)
    return ''.join(reversed(result))

def pi():
    """Compute Pi to the current precision.

    >>> print(pi())
    3.141592653589793238462643383

    """
    getcontext().prec += 2  # extra digits for intermediate steps
    three = Decimal(3)      # substitute "three=3.0" for regular floats
    lasts, t, s, n, na, d, da = 0, three, 3, 1, 0, 0, 24
    while s != lasts:
        lasts = s
        n, na = n+na, na+8
        d, da = d+da, da+32
        t = (t * n) / d
        s += t
    getcontext().prec -= 2
    return +s               # unary plus applies the new precision

def exp(x):
    """Return e raised to the power of x.  Result type matches input type.

    >>> print(exp(Decimal(1)))
    2.718281828459045235360287471
    >>> print(exp(Decimal(2)))
    7.389056098930650227230427461
    >>> print(exp(2.0))
    7.38905609893
    >>> print(exp(2+0j))
    (7.38905609893+0j)

    """
    getcontext().prec += 2
    i, lasts, s, fact, num = 0, 0, 1, 1, 1
    while s != lasts:
        lasts = s
        i += 1
        fact *= i
        num *= x
        s += num / fact
    getcontext().prec -= 2
    return +s

def cos(x):
    """Return the cosine of x as measured in radians.

    The Taylor series approximation works best for a small value of x.
    For larger values, first compute x = x % (2 * pi).

    >>> print(cos(Decimal('0.5')))
    0.8775825618903727161162815826
    >>> print(cos(0.5))
    0.87758256189
    >>> print(cos(0.5+0j))
    (0.87758256189+0j)

    """
    getcontext().prec += 2
    i, lasts, s, fact, num, sign = 0, 0, 1, 1, 1, 1
    while s != lasts:
        lasts = s
        i += 2
        fact *= i * (i-1)
        num *= x * x
        sign *= -1
        s += num / fact * sign
    getcontext().prec -= 2
    return +s

def sin(x):
    """Return the sine of x as measured in radians.

    The Taylor series approximation works best for a small value of x.
    For larger values, first compute x = x % (2 * pi).

    >>> print(sin(Decimal('0.5')))
    0.4794255386042030002732879352
    >>> print(sin(0.5))
    0.479425538604
    >>> print(sin(0.5+0j))
    (0.479425538604+0j)

    """
    getcontext().prec += 2
    i, lasts, s, fact, num, sign = 1, 0, x, 1, x, 1
    while s != lasts:
        lasts = s
        i += 2
        fact *= i * (i-1)
        num *= x * x
        sign *= -1
        s += num / fact * sign
    getcontext().prec -= 2
    return +s

Decimal FAQ

Q. decimal.Decimal('1234.5') 라고 입력하는 것은 귀찮은 일입니다. 대화형 인터프리터를 사용할 때 타자를 최소화할 방법이 있습니까?

A. 일부 사용자는 생성자를 하나의 문자로 축약합니다:

>>> D = decimal.Decimal
>>> D('1.23') + D('3.45')
Decimal('4.68')

Q. 소수점 두 자리의 고정 소수점 응용 프로그램에서, 일부 입력에 여러 자리가 있고 자리 올림 해야 합니다. 어떤 것은 여분의 자릿수가 없다고 가정되지만, 유효성 검사가 필요합니다. 어떤 방법을 사용해야 합니까?

A. The quantize() method rounds to a fixed number of decimal places. If the Inexact trap is set, it is also useful for validation:

>>> TWOPLACES = Decimal(10) ** -2       # same as Decimal('0.01')

>>> # Round to two places
>>> Decimal('3.214').quantize(TWOPLACES)
Decimal('3.21')

>>> # Validate that a number does not exceed two places
>>> Decimal('3.21').quantize(TWOPLACES, context=Context(traps=[Inexact]))
Decimal('3.21')

>>> Decimal('3.214').quantize(TWOPLACES, context=Context(traps=[Inexact]))
Traceback (most recent call last):
   ...
Inexact: None

Q. 일단 유효한 두 자리 입력이 있으면, 응용 프로그램 전체에서 해당 불변성을 어떻게 유지합니까?

A. Some operations like addition, subtraction, and multiplication by an integer will automatically preserve fixed point. Others operations, like division and non-integer multiplication, will change the number of decimal places and need to be followed-up with a quantize() step:

>>> a = Decimal('102.72')           # Initial fixed-point values
>>> b = Decimal('3.17')
>>> a + b                           # Addition preserves fixed-point
Decimal('105.89')
>>> a - b
Decimal('99.55')
>>> a * 42                          # So does integer multiplication
Decimal('4314.24')
>>> (a * b).quantize(TWOPLACES)     # Must quantize non-integer multiplication
Decimal('325.62')
>>> (b / a).quantize(TWOPLACES)     # And quantize division
Decimal('0.03')

In developing fixed-point applications, it is convenient to define functions to handle the quantize() step:

>>> def mul(x, y, fp=TWOPLACES):
...     return (x * y).quantize(fp)
...
>>> def div(x, y, fp=TWOPLACES):
...     return (x / y).quantize(fp)

>>> mul(a, b)                       # Automatically preserve fixed-point
Decimal('325.62')
>>> div(b, a)
Decimal('0.03')

Q. There are many ways to express the same value. The numbers 200, 200.000, 2E2, and .02E+4 all have the same value at various precisions. Is there a way to transform them to a single recognizable canonical value?

A. The normalize() method maps all equivalent values to a single representative:

>>> values = map(Decimal, '200 200.000 2E2 .02E+4'.split())
>>> [v.normalize() for v in values]
[Decimal('2E+2'), Decimal('2E+2'), Decimal('2E+2'), Decimal('2E+2')]

Q. When does rounding occur in a computation?

A. It occurs after the computation. The philosophy of the decimal specification is that numbers are considered exact and are created independent of the current context. They can even have greater precision than current context. Computations process with those exact inputs and then rounding (or other context operations) is applied to the result of the computation:

>>> getcontext().prec = 5
>>> pi = Decimal('3.1415926535')   # More than 5 digits
>>> pi                             # All digits are retained
Decimal('3.1415926535')
>>> pi + 0                         # Rounded after an addition
Decimal('3.1416')
>>> pi - Decimal('0.00005')        # Subtract unrounded numbers, then round
Decimal('3.1415')
>>> pi + 0 - Decimal('0.00005').   # Intermediate values are rounded
Decimal('3.1416')

Q. 일부 십진수 값은 항상 지수 표기법으로 인쇄됩니다. 지수가 아닌 표현을 얻을 방법이 있습니까?

A. For some values, exponential notation is the only way to express the number of significant places in the coefficient. For example, expressing 5.0E+3 as 5000 keeps the value constant but cannot show the original’s two-place significance.

응용 프로그램이 유효 숫자를 추적하는 데 신경 쓰지 않으면, 지수 및 후행 0을 제거하고 유효숫자를 잃지만, 값이 바뀌지 않도록 하기는 쉽습니다:

>>> def remove_exponent(d):
...     return d.quantize(Decimal(1)) if d == d.to_integral() else d.normalize()

>>> remove_exponent(Decimal('5E+3'))
Decimal('5000')

Q. 일반 float를 Decimal로 변환하는 방법이 있습니까?

A. Yes, any binary floating-point number can be exactly expressed as a Decimal though an exact conversion may take more precision than intuition would suggest:

>>> Decimal(math.pi)
Decimal('3.141592653589793115997963468544185161590576171875')

Q. 복잡한 계산에서, 정밀도가 부족하거나 자리 올림 이상이 발생하여 엉터리 결과를 얻지는 않았는지 확인하려면 어떻게 해야 합니까?

A. decimal 모듈은 결과를 쉽게 테스트할 수 있게 합니다. 가장 좋은 방법은 더 높은 정밀도와 다양한 자리 올림 모드를 사용하여 계산을 다시 실행하는 것입니다. 크게 다른 결과는 정밀도 부족, 자리 올림 모드 문제, 부적절한 입력 또는 수치가 불안정한 알고리즘을 나타냅니다.

컨텍스트 정밀도가 입력이 아닌 연산 결과에 적용된다는 사실을 확인했습니다. 다른 정밀도의 값을 혼합할 때 주의해야 할 것이 있습니까?

A. 그렇습니다. 원칙은 모든 값이 정확한 것으로 간주하므로 해당 값에 대한 산술도 마찬가지라는 것입니다. 결과 만 자리 올림 됩니다. 입력에 대한 이점은 “입력하는 것이 얻는 것”이라는 것입니다. 단점은 입력값을 자리 올림 하는 것을 잊어버리면 결과가 이상하게 보일 수 있다는 점입니다:

>>> getcontext().prec = 3
>>> Decimal('3.104') + Decimal('2.104')
Decimal('5.21')
>>> Decimal('3.104') + Decimal('0.000') + Decimal('2.104')
Decimal('5.20')

해법은 정밀도를 높이거나 단항 플러스 연산을 사용하여 입력의 자리 올림을 강제 수행하는 것입니다:

>>> getcontext().prec = 3
>>> +Decimal('1.23456789')      # unary plus triggers rounding
Decimal('1.23')

다른 방법으로, 입력은 Context.create_decimal() 메서드를 사용하여 생성 시에 자리 올림 될 수 있습니다:

>>> Context(prec=5, rounding=ROUND_DOWN).create_decimal('1.2345678')
Decimal('1.2345')

Q. CPython 구현은 커다란 수에서 빠릅니까?

A. Yes. In the CPython and PyPy3 implementations, the C/CFFI versions of the decimal module integrate the high speed libmpdec [https://www.bytereef.org/mpdecimal/doc/libmpdec/index.html] library for arbitrary precision correctly rounded decimal floating-point arithmetic [1]. libmpdec uses Karatsuba multiplication [https://en.wikipedia.org/wiki/Karatsuba_algorithm] for medium-sized numbers and the Number Theoretic Transform [https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general)#Number-theoretic_transform] for very large numbers.

The context must be adapted for exact arbitrary precision arithmetic. Emin and Emax should always be set to the maximum values, clamp should always be 0 (the default). Setting prec requires some care.

The easiest approach for trying out bignum arithmetic is to use the maximum value for prec as well [2]:

>>> setcontext(Context(prec=MAX_PREC, Emax=MAX_EMAX, Emin=MIN_EMIN))
>>> x = Decimal(2) ** 256
>>> x / 128
Decimal('904625697166532776746648320380374280103671755200316906558262375061821325312')

부정확한 결과의 경우, 64비트 플랫폼에서 MAX_PREC는 너무 크고 사용 가능한 메모리가 충분하지 않을 것입니다:

>>> Decimal(1) / 3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
MemoryError

On systems with overallocation (e.g. Linux), a more sophisticated approach is to adjust prec to the amount of available RAM. Suppose that you have 8GB of RAM and expect 10 simultaneous operands using a maximum of 500MB each:

>>> import sys
>>>
>>> # Maximum number of digits for a single operand using 500MB in 8-byte words
>>> # with 19 digits per word (4-byte and 9 digits for the 32-bit build):
>>> maxdigits = 19 * ((500 * 1024**2) // 8)
>>>
>>> # Check that this works:
>>> c = Context(prec=maxdigits, Emax=MAX_EMAX, Emin=MIN_EMIN)
>>> c.traps[Inexact] = True
>>> setcontext(c)
>>>
>>> # Fill the available precision with nines:
>>> x = Decimal(0).logical_invert() * 9
>>> sys.getsizeof(x)
524288112
>>> x + 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  decimal.Inexact: [<class 'decimal.Inexact'>]

일반적으로 (그리고 특히 초과 할당이 없는 시스템에서), 더 엄격한 경계를 추정하고 모든 계산이 정확할 것으로 예상되면 Inexact 트랩을 설정하는 것이 좋습니다.

[1]

Added in version 3.3.

[2]

버전 3.9에서 변경: 이 접근법은 정수가 아닌 거듭제곱을 제외한 모든 정확한 결과에 적용됩니다.

fractions — Rational numbers

소스 코드: Lib/fractions.py [https://github.com/python/cpython/tree/main/Lib/fractions.py]

fractions 모듈은 유리수 산술을 지원합니다.

Fraction 인스턴스는 한 쌍의 정수, 다른 유리수 또는 문자열로 만들 수 있습니다.

class fractions.Fraction(numerator=0, denominator=1)

class fractions.Fraction(number)

class fractions.Fraction(string)

The first version requires that numerator and denominator are instances of numbers.Rational and returns a new Fraction instance with value numerator/denominator. If denominator is 0, it raises a ZeroDivisionError.

The second version requires that number is an instance of numbers.Rational or has the as_integer_ratio() method (this includes float and decimal.Decimal). It returns a Fraction instance with exactly the same value. Assumed, that the as_integer_ratio() method returns a pair of coprime integers and last one is positive. Note that due to the usual issues with binary point (see Floating-Point Arithmetic: Issues and Limitations), the argument to Fraction(1.1) is not exactly equal to 11/10, and so Fraction(1.1) does not return Fraction(11, 10) as one might expect. (But see the documentation for the limit_denominator() method below.)

The last version of the constructor expects a string. The usual form for this instance is:

[sign] numerator ['/' denominator]

where the optional sign may be either ‘+’ or ‘-’ and numerator and denominator (if present) are strings of decimal digits (underscores may be used to delimit digits as with integral literals in code). In addition, any string that represents a finite value and is accepted by the float constructor is also accepted by the Fraction constructor. In either form the input string may also have leading and/or trailing whitespace. Here are some examples:

>>> from fractions import Fraction
>>> Fraction(16, -10)
Fraction(-8, 5)
>>> Fraction(123)
Fraction(123, 1)
>>> Fraction()
Fraction(0, 1)
>>> Fraction('3/7')
Fraction(3, 7)
>>> Fraction(' -3/7 ')
Fraction(-3, 7)
>>> Fraction('1.414213 \t\n')
Fraction(1414213, 1000000)
>>> Fraction('-.125')
Fraction(-1, 8)
>>> Fraction('7e-6')
Fraction(7, 1000000)
>>> Fraction(2.25)
Fraction(9, 4)
>>> Fraction(1.1)
Fraction(2476979795053773, 2251799813685248)
>>> from decimal import Decimal
>>> Fraction(Decimal('1.1'))
Fraction(11, 10)

The Fraction class inherits from the abstract base class numbers.Rational, and implements all of the methods and operations from that class. Fraction instances are hashable, and should be treated as immutable. In addition, Fraction has the following properties and methods:

버전 3.2에서 변경: Fraction 생성자는 이제 float와 decimal.Decimal 인스턴스를 받아들입니다.

버전 3.9에서 변경: The math.gcd() function is now used to normalize the numerator and denominator. math.gcd() always returns an int type. Previously, the GCD type depended on numerator and denominator.

버전 3.11에서 변경: Underscores are now permitted when creating a Fraction instance from a string, following PEP 515 [https://peps.python.org/pep-0515/] rules.

버전 3.11에서 변경: Fraction implements __int__ now to satisfy typing.SupportsInt instance checks.

버전 3.12에서 변경: Space is allowed around the slash for string inputs: Fraction('2 / 3').

버전 3.12에서 변경: Fraction instances now support float-style formatting, with presentation types "e", "E", "f", "F", "g", "G" and "%"".

버전 3.13에서 변경: Formatting of Fraction instances without a presentation type now supports fill, alignment, sign handling, minimum width and grouping.

버전 3.14에서 변경: The Fraction constructor now accepts any objects with the as_integer_ratio() method.

numerator

기약 분수로 나타낼 때 Fraction의 분자.

denominator

기약 분수로 나타낼 때 Fraction의 분모.

as_integer_ratio()

Return a tuple of two integers, whose ratio is equal to the original Fraction. The ratio is in lowest terms and has a positive denominator.

Added in version 3.8.

is_integer()

Return True if the Fraction is an integer.

Added in version 3.12.

classmethod from_float(flt)

Alternative constructor which only accepts instances of float or numbers.Integral. Beware that Fraction.from_float(0.3) is not the same value as Fraction(3, 10).

참고

파이썬 3.2 이상에서는, float에서 직접 Fraction 인스턴스를 생성할 수도 있습니다.

classmethod from_decimal(dec)

Alternative constructor which only accepts instances of decimal.Decimal or numbers.Integral.

참고

파이썬 3.2 이상에서는, decimal.Decimal 인스턴스에서 직접 Fraction 인스턴스를 생성할 수도 있습니다.

classmethod from_number(number)

Alternative constructor which only accepts instances of numbers.Integral, numbers.Rational, float or decimal.Decimal, and objects with the as_integer_ratio() method, but not strings.

Added in version 3.14.

limit_denominator(max_denominator=1000000)

분모가 최대 max_denominator인 self에 가장 가까운 Fraction을 찾아서 반환합니다. 이 메서드는 주어진 부동 소수점 수에 대한 유리한 근사를 찾는 데 유용합니다:

>>> from fractions import Fraction
>>> Fraction('3.1415926535897932').limit_denominator(1000)
Fraction(355, 113)

또는 float로 표현된 유리수를 복구할 때 유용합니다:

>>> from math import pi, cos
>>> Fraction(cos(pi/3))
Fraction(4503599627370497, 9007199254740992)
>>> Fraction(cos(pi/3)).limit_denominator()
Fraction(1, 2)
>>> Fraction(1.1).limit_denominator()
Fraction(11, 10)

__floor__()

가장 큰 int <= self를 반환합니다. 이 메서드는 math.floor() 함수를 통해 액세스할 수도 있습니다:

>>> from math import floor
>>> floor(Fraction(355, 113))
3

__ceil__()

가장 작은 int >= self를 반환합니다. 이 메서드는 math.ceil() 함수를 통해 액세스할 수도 있습니다.

__round__()

__round__(ndigits)

첫 번째 버전은 self에 가장 가까운 int를 반환하는데, 절반은 짝수로 자리 올림 합니다. 두 번째 버전은 self를 가장 가까운 Fraction(1, 10**ndigits)의 배수로 자리 올림 하는데 (ndigits가 음수면 논리적으로), 역시 짝수로 자리 올림 합니다. 이 메서드는 round() 함수를 통해 액세스할 수도 있습니다.

__format__(format_spec, /)

Provides support for formatting of Fraction instances via the str.format() method, the format() built-in function, or Formatted string literals.

If the format_spec format specification string does not end with one of the presentation types 'e', 'E', 'f', 'F', 'g', 'G' or '%' then formatting follows the general rules for fill, alignment, sign handling, minimum width, and grouping as described in the format specification mini-language. The “alternate form” flag '#' is supported: if present, it forces the output string to always include an explicit denominator, even when the value being formatted is an exact integer. The zero-fill flag '0' is not supported.

If the format_spec format specification string ends with one of the presentation types 'e', 'E', 'f', 'F', 'g', 'G' or '%' then formatting follows the rules outlined for the float type in the 포맷 명세 미니 언어 section.

Here are some examples:

>>> from fractions import Fraction
>>> format(Fraction(103993, 33102), '_')
'103_993/33_102'
>>> format(Fraction(1, 7), '.^+10')
'...+1/7...'
>>> format(Fraction(3, 1), '')
'3'
>>> format(Fraction(3, 1), '#')
'3/1'
>>> format(Fraction(1, 7), '.40g')
'0.1428571428571428571428571428571428571429'
>>> format(Fraction('1234567.855'), '_.2f')
'1_234_567.86'
>>> f"{Fraction(355, 113):*>20.6e}"
'********3.141593e+00'
>>> old_price, new_price = 499, 672
>>> "{:.2%} price increase".format(Fraction(new_price, old_price) - 1)
'34.67% price increase'

더 보기

모듈 numbers

숫자 계층을 구성하는 추상 베이스 클래스.

random — Generate pseudo-random numbers

소스 코드: Lib/random.py [https://github.com/python/cpython/tree/main/Lib/random.py]

이 모듈은 다양한 분포에 대한 의사 난수 생성기를 구현합니다.

정수에 대해서는, 범위에서 균일한 선택이 있습니다. 시퀀스에 대해서는, 무작위 요소의 균일한 선택, 리스트를 제자리(in-place)에서 임의 순열을 생성하는 함수 및 중복 없는(without replacement) 무작위 표본 추출(sampling)을 위한 함수가 있습니다.

실수에 대해서는, 균일(uniform), 정규(normal) (가우시안(Gaussian)), 로그 정규(lognormal), 음의 지수(negative exponential), 감마(gamma) 및 베타(beta) 분포를 계산하는 함수가 있습니다. 각도 분포를 생성하기 위해, 폰 미제스(von Mises) 분포를 사용할 수 있습니다.

Almost all module functions depend on the basic function random(), which generates a random float uniformly in the half-open range 0.0 <= X < 1.0. Python uses the Mersenne Twister as the core generator. It produces 53-bit precision floats and has a period of 2**19937-1. The underlying implementation in C is both fast and threadsafe. The Mersenne Twister is one of the most extensively tested random number generators in existence. However, being completely deterministic, it is not suitable for all purposes, and is completely unsuitable for cryptographic purposes.

이 모듈에서 제공하는 함수는 실제로는 random.Random 클래스의 숨겨진 인스턴스에 대해 연결된 메서드입니다. Random 인스턴스를 직접 인스턴스 화하여 상태를 공유하지 않는 생성기를 얻을 수 있습니다.

Class Random can also be subclassed if you want to use a different basic generator of your own devising: see the documentation on that class for more details.

random 모듈은 운영 체제에서 제공하는 소스에서 난수를 생성하는 시스템 함수 os.urandom()을 사용하는 SystemRandom 클래스도 제공합니다.

경고

이 모듈의 의사 난수 생성기를 보안 목적으로 사용해서는 안 됩니다. 보안이나 암호화 용도를 위해서는, secrets 모듈을 참조하십시오.

더 보기

M. Matsumoto and T. Nishimura, “Mersenne Twister: A 623-dimensionally equidistributed uniform pseudorandom number generator”, ACM Transactions on Modeling and Computer Simulation Vol. 8, No. 1, January pp.3–30 1998.

Complementary-Multiply-with-Carry recipe [https://code.activestate.com/recipes/576707-long-period-random-number-generator/] for a compatible alternative random number generator with a long period and comparatively simple update operations.

참고

The global random number generator and instances of Random are thread-safe. However, in the free-threaded build, concurrent calls to the global generator or to the same instance of Random may encounter contention and poor performance. Consider using separate instances of Random per thread instead.

관리 함수

random.seed(a=None, version=2)

난수 생성기를 초기화합니다.

a가 생략되거나 None이면, 현재 시스템 시간이 사용됩니다. 운영 체제에서 임의성 소스(randomness sources)를 제공하면, 시스템 시간 대신 사용됩니다 (가용성에 대한 자세한 내용은 os.urandom() 함수를 참조하십시오).

a가 int이면, 직접 사용됩니다.

버전(version) 2(기본값)에서는, str, bytes 또는 bytearray 객체가 int로 변환되어 모든 비트가 사용됩니다.

버전(version) 1(이전 버전의 파이썬에서 온 임의의 시퀀스를 재현하기 위해 제공됩니다)에서는, str과 bytes를 위한 알고리즘은 더 좁은 범위의 시드(seed)를 생성합니다.

버전 3.2에서 변경: 문자열 시드의 모든 비트를 사용하는 버전 2 체계로 이동했습니다.

버전 3.11에서 변경: The seed must be one of the following types: None, int, float, str, bytes, or bytearray.

random.getstate()

생성기의 현재 내부 상태를 포착하는 객체를 반환합니다. 이 객체는 setstate()로 전달되어 상태를 복원 할 수 있습니다.

random.setstate(state)

state는 getstate()에 대한 이전 호출에서 얻은 것이어야 하고, setstate()는 생성기의 내부 상태를 getstate()가 호출될 당시의 상태로 복원합니다.

바이트열 함수

random.randbytes(n)

n 무작위 바이트를 생성합니다.

이 메서드를 사용하여 보안 토큰을 생성해서는 안 됩니다. 대신 secrets.token_bytes()를 사용하십시오.

Added in version 3.9.

정수 함수

random.randrange(stop)

random.randrange(start, stop[, step])

Return a randomly selected element from range(start, stop, step).

This is roughly equivalent to choice(range(start, stop, step)) but supports arbitrarily large ranges and is optimized for common cases.

The positional argument pattern matches the range() function.

Keyword arguments should not be used because they can be interpreted in unexpected ways. For example randrange(start=100) is interpreted as randrange(0, 100, 1).

버전 3.2에서 변경: randrange()는 균일하게 분포된 값을 생성하는 데 있어 더욱 정교합니다. 이전에는 약간 고르지 않은 분포를 생성 할 수 있는 int(random()*n)와 같은 스타일을 사용했습니다.

버전 3.12에서 변경: Automatic conversion of non-integer types is no longer supported. Calls such as randrange(10.0) and randrange(Fraction(10, 1)) now raise a TypeError.

random.randint(a, b)

a <= N <= b를 만족하는 임의의 정수 N을 반환합니다. randrange(a, b+1)의 별칭.

random.getrandbits(k)

Returns a non-negative Python integer with k random bits. This method is supplied with the Mersenne Twister generator and some other generators may also provide it as an optional part of the API. When available, getrandbits() enables randrange() to handle arbitrarily large ranges.

버전 3.9에서 변경: 이 메서드는 이제 k에 0을 허용합니다.

시퀀스 함수

random.choice(seq)

비어 있지 않은 시퀀스 seq에서 임의의 요소를 반환합니다. seq가 비어 있으면, IndexError를 발생시킵니다.

random.choices(population, weights=None, *, cum_weights=None, k=1)

population에서 중복을 허락하면서(with replacement) 선택한 k 크기의 요소 리스트를 반환합니다. population이 비어 있으면, IndexError를 발생시킵니다.

weights 시퀀스가 지정되면, 상대 가중치에 따라 선택됩니다. 대안적으로, cum_weights 시퀀스가 제공되면, (아마도 itertools.accumulate()를 사용하여 계산된) 누적 가중치(cumulative weights)에 따라 선택이 이루어집니다. 예를 들어, 상대 가중치 [10, 5, 30, 5]는 누적 가중치 [10, 15, 45, 50]과 동등합니다. 내부적으로, 상대 가중치는 선택하기 전에 누적 가중치로 변환되므로, 누적 가중치를 제공하면 작업이 줄어듭니다.

weights나 cum_weights를 지정하지 않으면, 같은 확률로 선택됩니다. weights 시퀀스가 제공되면, population 시퀀스와 길이가 같아야 합니다. weights와 cum_weights를 모두 지정하는 것은 TypeError입니다.

The weights or cum_weights can use any numeric type that interoperates with the float values returned by random() (that includes integers, floats, and fractions but excludes decimals). Weights are assumed to be non-negative and finite. A ValueError is raised if all weights are zero.

For a given seed, the choices() function with equal weighting typically produces a different sequence than repeated calls to choice(). The algorithm used by choices() uses floating-point arithmetic for internal consistency and speed. The algorithm used by choice() defaults to integer arithmetic with repeated selections to avoid small biases from round-off error.

Added in version 3.6.

버전 3.9에서 변경: 모든 가중치가 0이면 ValueError를 발생시킵니다.

random.shuffle(x)

시퀀스 x를 제자리에서 섞습니다.

불변 시퀀스를 섞고 새로운 섞인 리스트를 반환하려면, 대신 sample(x, k=len(x))를 사용하십시오.

작은 len(x)의 경우에조차, x의 총 순열 수는 대부분의 난수 생성기 주기보다 빠르게 커질 수 있습니다. 이것은 긴 시퀀스의 대부분 순열이 절대로 생성될 수 없음을 의미합니다. 예를 들어, 길이가 2080인 시퀀스가 메르센 트위스터 난수 생성기의 주기 안에 들어갈 수 있는 최대입니다.

버전 3.11에서 변경: Removed the optional parameter random.

random.sample(population, k, *, counts=None)

Return a k length list of unique elements chosen from the population sequence. Used for random sampling without replacement.

원래 population을 변경하지 않고, population의 요소를 포함하는 새 리스트를 반환합니다. 결과 리스트는 선택 순서를 따라서, 모든 서브 슬라이스도 유효한 임의의 표본이 됩니다. 이것은 추첨 당첨자(표본)를 대상(grand prize)과 차점자들(서브 슬라이스)로 나눌 수 있도록 합니다.

population의 멤버는 해시 가능하거나 고유할 필요가 없습니다. population이 반복을 포함하면, 각 등장(occurrence)은 표본에서 가능한 선택입니다.

반복되는 요소는 한 번에 하나씩 또는 선택적 키워드 전용 counts 매개 변수로 지정할 수 있습니다. 예를 들어 sample(['red', 'blue'], counts=[4, 2], k=5)는 sample(['red', 'red', 'red', 'red', 'blue', 'blue'], k=5)와 동등합니다.

정수 범위에서 표본을 선택하려면, range() 객체를 인자로 사용하십시오. 이는 큰 population에서 표본 추출할 때 특히 빠르고 공간 효율적입니다: sample(range(10000000), k=60).

표본 크기가 population 크기보다 크면 ValueError가 발생합니다.

버전 3.9에서 변경: counts 매개 변수를 추가했습니다.

버전 3.11에서 변경: The population must be a sequence. Automatic conversion of sets to lists is no longer supported.

Discrete distributions

The following function generates a discrete distribution.

random.binomialvariate(n=1, p=0.5)

Binomial distribution [https://mathworld.wolfram.com/BinomialDistribution.html]. Return the number of successes for n independent trials with the probability of success in each trial being p:

Mathematically equivalent to:

sum(random() < p for i in range(n))

The number of trials n should be a non-negative integer. The probability of success p should be between 0.0 <= p <= 1.0. The result is an integer in the range 0 <= X <= n.

Added in version 3.12.

실수 분포

다음 함수는 특정 실수 분포를 생성합니다. 함수 매개 변수는 일반적인 수학적 관행에 사용되는 분포 방정식에서 해당 변수의 이름을 따서 명명됩니다; 이러한 방정식의 대부분은 모든 통계 교과서에서 찾을 수 있습니다.

random.random()

Return the next random floating-point number in the range 0.0 <= X < 1.0

random.uniform(a, b)

Return a random floating-point number N such that a <= N <= b for a <= b and b <= N <= a for b < a.

The end-point value b may or may not be included in the range depending on floating-point rounding in the expression a + (b-a) * random().

random.triangular(low, high, mode)

Return a random floating-point number N such that low <= N <= high and with the specified mode between those bounds. The low and high bounds default to zero and one. The mode argument defaults to the midpoint between the bounds, giving a symmetric distribution.

random.betavariate(alpha, beta)

베타 분포. 매개 변수의 조건은 alpha > 0과 beta > 0입니다. 반환된 값의 범위는 0에서 1입니다.

random.expovariate(lambd=1.0)

지수 분포. lambd는 1.0을 원하는 평균으로 나눈 값입니다. 0이 아니어야 합니다. (매개 변수는 “lambda”라고 부르지만, 파이썬에서는 예약어입니다.) 반환된 값의 범위는, lambd가 양수이면 0에서 양의 무한대이고, lambd가 음수이면 음의 무한대에서 0입니다.

버전 3.12에서 변경: Added the default value for lambd.

random.gammavariate(alpha, beta)

Gamma distribution. (Not the gamma function!) The shape and scale parameters, alpha and beta, must have positive values. (Calling conventions vary and some sources define ‘beta’ as the inverse of the scale).

확률 분포 함수는 다음과 같습니다:

          x ** (alpha - 1) * math.exp(-x / beta)
pdf(x) =  --------------------------------------
            math.gamma(alpha) * beta ** alpha

random.gauss(mu=0.0, sigma=1.0)

Normal distribution, also called the Gaussian distribution. mu is the mean, and sigma is the standard deviation. This is slightly faster than the normalvariate() function defined below.

다중 스레딩 참고: 두 스레드가 이 함수를 동시에 호출하면, 같은 반환 값을 받을 수 있습니다. 이것은 세 가지 방법으로 피할 수 있습니다. 1) 각 스레드가 난수 생성기의 다른 인스턴스를 사용하도록 합니다. 2) 모든 호출에 록을 둡니다. 3) 더 느리지만, 스레드 안전한 normalvariate() 함수를 대신 사용합니다.

버전 3.11에서 변경: mu and sigma now have default arguments.

random.lognormvariate(mu, sigma)

로그 정규 분포. 이 분포의 자연로그를 취하면, 평균 mu와 표준 편차 sigma를 갖는 정규 분포를 얻게 됩니다. mu는 아무 값이나 될 수 있으며, sigma는 0보다 커야 합니다.

random.normalvariate(mu=0.0, sigma=1.0)

정규 분포. mu는 평균이고, sigma는 표준 편차입니다.

버전 3.11에서 변경: mu and sigma now have default arguments.

random.vonmisesvariate(mu, kappa)

mu는 0과 2*pi 사이의 라디안으로 표현된 평균 각도이며, kappa는 0 이상이어야 하는 집중도(concentration) 매개 변수입니다. kappa가 0이면, 이 분포는 0에서 2*pi에 걸친 균등한 임의의 각도로 환원됩니다.

random.paretovariate(alpha)

파레토 분포. alpha는 모양(shape) 매개 변수입니다.

random.weibullvariate(alpha, beta)

베이불 분포. alpha는 크기(scale) 매개 변수이고 beta는 모양(shape) 매개 변수입니다.

대체 생성기

class random.Random([seed])

random 모듈에서 사용하는 기본 의사 난수 생성기를 구현하는 클래스.

버전 3.11에서 변경: Formerly the seed could be any hashable object. Now it is limited to: None, int, float, str, bytes, or bytearray.

Subclasses of Random should override the following methods if they wish to make use of a different basic generator:

seed(a=None, version=2)

Override this method in subclasses to customise the seed() behaviour of Random instances.

getstate()

Override this method in subclasses to customise the getstate() behaviour of Random instances.

setstate(state)

Override this method in subclasses to customise the setstate() behaviour of Random instances.

random()

Override this method in subclasses to customise the random() behaviour of Random instances.

Optionally, a custom generator subclass can also supply the following method:

getrandbits(k)

Override this method in subclasses to customise the getrandbits() behaviour of Random instances.

class random.SystemRandom([seed])

운영 체제에서 제공하는 소스에서 난수를 생성하기 위해 os.urandom() 함수를 사용하는 클래스. 모든 시스템에서 사용 가능한 것은 아닙니다. 소프트웨어 상태에 의존하지 않으며, 시퀀스는 재현되지 않습니다. 따라서, seed() 메서드는 효과가 없으며, 무시됩니다. getstate()와 setstate() 메서드는 호출되면 NotImplementedError를 발생시킵니다.

재현성에 대한 참고 사항

Sometimes it is useful to be able to reproduce the sequences given by a pseudo-random number generator. By reusing a seed value, the same sequence should be reproducible from run to run as long as multiple threads are not running.

random 모듈의 알고리즘과 시딩(seeding) 함수의 대부분은 파이썬 버전에 따라 변경될 수 있지만, 두 가지 측면은 변경되지 않음이 보장됩니다:

새로운 시딩 메서드가 추가되면, 이전 버전과 호환되는 시더(seeder)가 제공될 것입니다.

호환 시더에 같은 시드가 제공되면 생성기의 random() 메서드는 같은 시퀀스를 계속 생성할 것입니다.

예제

기본 예제:

>>> random()                          # Random float:  0.0 <= x < 1.0
0.37444887175646646

>>> uniform(2.5, 10.0)                # Random float:  2.5 <= x <= 10.0
3.1800146073117523

>>> expovariate(1 / 5)                # Interval between arrivals averaging 5 seconds
5.148957571865031

>>> randrange(10)                     # Integer from 0 to 9 inclusive
7

>>> randrange(0, 101, 2)              # Even integer from 0 to 100 inclusive
26

>>> choice(['win', 'lose', 'draw'])   # Single random element from a sequence
'draw'

>>> deck = 'ace two three four'.split()
>>> shuffle(deck)                     # Shuffle a list
>>> deck
['four', 'two', 'ace', 'three']

>>> sample([10, 20, 30, 40, 50], k=4) # Four samples without replacement
[40, 10, 50, 30]

시뮬레이션:

>>> # Six roulette wheel spins (weighted sampling with replacement)
>>> choices(['red', 'black', 'green'], [18, 18, 2], k=6)
['red', 'green', 'black', 'black', 'red', 'black']

>>> # Deal 20 cards without replacement from a deck
>>> # of 52 playing cards, and determine the proportion of cards
>>> # with a ten-value:  ten, jack, queen, or king.
>>> deal = sample(['tens', 'low cards'], counts=[16, 36], k=20)
>>> deal.count('tens') / 20
0.15

>>> # Estimate the probability of getting 5 or more heads from 7 spins
>>> # of a biased coin that settles on heads 60% of the time.
>>> sum(binomialvariate(n=7, p=0.6) >= 5 for i in range(10_000)) / 10_000
0.4169

>>> # Probability of the median of 5 samples being in middle two quartiles
>>> def trial():
...     return 2_500 <= sorted(choices(range(10_000), k=5))[2] < 7_500
...
>>> sum(trial() for i in range(10_000)) / 10_000
0.7958

표본의 평균에 대한 신뢰 구간을 추정하기 위해 중복을 허용하는(with replacement) 재표본추출(resampling)을 사용하는 통계적 부트스트래핑(statistical bootstrapping) [https://en.wikipedia.org/wiki/Bootstrapping_(statistics)]의 예:

# https://www.thoughtco.com/example-of-bootstrapping-3126155
from statistics import fmean as mean
from random import choices

data = [41, 50, 29, 37, 81, 30, 73, 63, 20, 35, 68, 22, 60, 31, 95]
means = sorted(mean(choices(data, k=len(data))) for i in range(100))
print(f'The sample mean of {mean(data):.1f} has a 90% confidence '
      f'interval from {means[5]:.1f} to {means[94]:.1f}')

약물과 위약의 효과 간에 관찰된 차이의 통계적 유의성 또는 p-값 [https://en.wikipedia.org/wiki/P-value]을 결정하기 위한 재표본추출 순열 검증(resampling permutation test) [https://en.wikipedia.org/wiki/Resampling_(statistics)#Permutation_tests]의 예:

# Example from "Statistics is Easy" by Dennis Shasha and Manda Wilson
from statistics import fmean as mean
from random import shuffle

drug = [54, 73, 53, 70, 73, 68, 52, 65, 65]
placebo = [54, 51, 58, 44, 55, 52, 42, 47, 58, 46]
observed_diff = mean(drug) - mean(placebo)

n = 10_000
count = 0
combined = drug + placebo
for i in range(n):
    shuffle(combined)
    new_diff = mean(combined[:len(drug)]) - mean(combined[len(drug):])
    count += (new_diff >= observed_diff)

print(f'{n} label reshufflings produced only {count} instances with a difference')
print(f'at least as extreme as the observed difference of {observed_diff:.1f}.')
print(f'The one-sided p-value of {count / n:.4f} leads us to reject the null')
print(f'hypothesis that there is no difference between the drug and the placebo.')

다중 서버 큐를 위한 도착 시간과 서비스 제공의 시뮬레이션:

from heapq import heapify, heapreplace
from random import expovariate, gauss
from statistics import mean, quantiles

average_arrival_interval = 5.6
average_service_time = 15.0
stdev_service_time = 3.5
num_servers = 3

waits = []
arrival_time = 0.0
servers = [0.0] * num_servers  # time when each server becomes available
heapify(servers)
for i in range(1_000_000):
    arrival_time += expovariate(1.0 / average_arrival_interval)
    next_server_available = servers[0]
    wait = max(0.0, next_server_available - arrival_time)
    waits.append(wait)
    service_duration = max(0.0, gauss(average_service_time, stdev_service_time))
    service_completed = arrival_time + wait + service_duration
    heapreplace(servers, service_completed)

print(f'Mean wait: {mean(waits):.1f}   Max wait: {max(waits):.1f}')
print('Quartiles:', [round(q, 1) for q in quantiles(waits)])

더 보기

시뮬레이션(simulation), 표본 추출(sampling), 섞기(shuffling) 및 교차 검증(cross-validation)을 포함하는 몇 가지 기본 개념만을 사용한, 통계 분석에 대한 Jake Vanderplas [https://us.pycon.org/2016/speaker/profile/295/]의 비디오 자습서 Statistics for Hackers [https://www.youtube.com/watch?v=Iq9DzN6mvYA]

Economics Simulation [https://nbviewer.org/url/norvig.com/ipython/Economics.ipynb] a simulation of a marketplace by Peter Norvig [https://norvig.com/bio.html] that shows effective use of many of the tools and distributions provided by this module (gauss, uniform, sample, betavariate, choice, triangular, and randrange).

A Concrete Introduction to Probability (using Python) [https://nbviewer.org/url/norvig.com/ipython/Probability.ipynb] a tutorial by Peter Norvig [https://norvig.com/bio.html] covering the basics of probability theory, how to write simulations, and how to perform data analysis using Python.

조리법

These recipes show how to efficiently make random selections from the combinatoric iterators in the itertools module:

def random_product(*args, repeat=1):
    "Random selection from itertools.product(*args, **kwds)"
    pools = [tuple(pool) for pool in args] * repeat
    return tuple(map(random.choice, pools))

def random_permutation(iterable, r=None):
    "Random selection from itertools.permutations(iterable, r)"
    pool = tuple(iterable)
    r = len(pool) if r is None else r
    return tuple(random.sample(pool, r))

def random_combination(iterable, r):
    "Random selection from itertools.combinations(iterable, r)"
    pool = tuple(iterable)
    n = len(pool)
    indices = sorted(random.sample(range(n), r))
    return tuple(pool[i] for i in indices)

def random_combination_with_replacement(iterable, r):
    "Choose r elements with replacement.  Order the result to match the iterable."
    # Result will be in set(itertools.combinations_with_replacement(iterable, r)).
    pool = tuple(iterable)
    n = len(pool)
    indices = sorted(random.choices(range(n), k=r))
    return tuple(pool[i] for i in indices)

기본 random()은 0.0 ≤ x < 1.0 범위에서 2⁻⁵³의 배수를 반환합니다. 이러한 모든 숫자는 균등 간격으로 분포되어있고 파이썬 float로 정확하게 표현할 수 있습니다. 그러나, 해당 범위의 다른 많은 표현 가능한 부동 소수점은 가능한 선택이 아닙니다. 예를 들어, 0.05954861408025609는 2⁻⁵³의 정수배가 아닙니다.

다음 조리법은 다른 접근 방식을 사용합니다. 범위의 모든 부동 소수점이 가능한 선택입니다. 가수(mantissa)는 2⁵² ≤ mantissa < 2⁵³ 범위에 있는 정수의 균등 분포(uniform distribution)에서 옵니다. 지수(exponent)는 -53보다 작은 지수가 다음으로 큰 지수의 절반만큼 자주 발생하는 기하 분포(geometric distribution)에서 옵니다.

from random import Random
from math import ldexp

class FullRandom(Random):

    def random(self):
        mantissa = 0x10_0000_0000_0000 | self.getrandbits(52)
        exponent = -53
        x = 0
        while not x:
            x = self.getrandbits(32)
            exponent += x.bit_length() - 32
        return ldexp(mantissa, exponent)

클래스의 모든 실숫값 분포는 새 메서드를 사용합니다:

>>> fr = FullRandom()
>>> fr.random()
0.05954861408025609
>>> fr.expovariate(0.25)
8.87925541791544

조리법은 개념적으로 0.0 ≤ x < 1.0 범위의 2⁻¹⁰⁷⁴의 모든 배수에서 선택하는 알고리즘과 동등합니다. 이러한 모든 숫자는 균등한 간격이지만, 대부분은 가장 가까운 표현 가능한 파이썬 부동 소수점으로 자리 내림해야 합니다. (값 2⁻¹⁰⁷⁴은 가장 작은 양의 정규화되지 않은 부동 소수점이며 math.ulp(0.0)과 같습니다.)

더 보기

Generating Pseudo-random Floating-Point Values [https://allendowney.com/research/rand/downey07randfloat.pdf] Allen B. Downey의 논문은 random()이 일반적으로 생성하는 것보다 더 세밀한 부동 소수점을 생성하는 방법을 설명합니다.

Command-line usage

Added in version 3.13.

The random module can be executed from the command line.

python -m random [-h] [-c CHOICE [CHOICE ...] | -i N | -f N] [input ...]

The following options are accepted:

-h, --help

Show the help message and exit.

-c CHOICE [CHOICE ...]

--choice CHOICE [CHOICE ...]

Print a random choice, using choice().

-i <N>

--integer <N>

Print a random integer between 1 and N inclusive, using randint().

-f <N>

--float <N>

Print a random floating-point number between 0 and N inclusive, using uniform().

If no options are given, the output depends on the input:

String or multiple: same as --choice.

Integer: same as --integer.

Float: same as --float.

Command-line example

Here are some examples of the random command-line interface:

$ # Choose one at random
$ python -m random egg bacon sausage spam "Lobster Thermidor aux crevettes with a Mornay sauce"
Lobster Thermidor aux crevettes with a Mornay sauce

$ # Random integer
$ python -m random 6
6

$ # Random floating-point number
$ python -m random 1.8
1.7080016272295635

$ # With explicit arguments
$ python  -m random --choice egg bacon sausage spam "Lobster Thermidor aux crevettes with a Mornay sauce"
egg

$ python -m random --integer 6
3

$ python -m random --float 1.8
1.5666339105010318

$ python -m random --integer 6
5

$ python -m random --float 6
3.1942323316565915

statistics — Mathematical statistics functions

Added in version 3.4.

소스 코드: Lib/statistics.py [https://github.com/python/cpython/tree/main/Lib/statistics.py]

이 모듈은 숫자 (Real 값) 데이터의 수학적 통계를 계산하는 함수를 제공합니다.

The module is not intended to be a competitor to third-party libraries such as NumPy [https://numpy.org], SciPy [https://scipy.org/], or proprietary full-featured statistics packages aimed at professional statisticians such as Minitab, SAS and Matlab. It is aimed at the level of graphing and scientific calculators.

달리 명시되지 않는 한, 이 함수는 int, float, decimal.Decimal 및 fractions.Fraction을 지원합니다. 다른 형(숫자 계층에 있든 없든)에서의 동작은 현재 지원되지 않습니다. 여러 형의 컬렉션도 정의되지 않으며 구현에 따라 다릅니다. 입력 데이터가 혼합형으로 구성되었으면, map()을 사용하여 일관된 결과를 보장 할 수 있습니다, 예를 들어 map(float, input_data).

Some datasets use NaN (not a number) values to represent missing data. Since NaNs have unusual comparison semantics, they cause surprising or undefined behaviors in the statistics functions that sort data or that count occurrences. The functions affected are median(), median_low(), median_high(), median_grouped(), mode(), multimode(), and quantiles(). The NaN values should be stripped before calling these functions:

>>> from statistics import median
>>> from math import isnan
>>> from itertools import filterfalse

>>> data = [20.7, float('NaN'),19.2, 18.3, float('NaN'), 14.4]
>>> sorted(data)  # This has surprising behavior
[20.7, nan, 14.4, 18.3, 19.2, nan]
>>> median(data)  # This result is unexpected
16.35

>>> sum(map(isnan, data))    # Number of missing values
2
>>> clean = list(filterfalse(isnan, data))  # Strip NaN values
>>> clean
[20.7, 19.2, 18.3, 14.4]
>>> sorted(clean)  # Sorting now works as expected
[14.4, 18.3, 19.2, 20.7]
>>> median(clean)       # This result is now well defined
18.75

평균과 중심 위치의 측정

이 함수는 모집단(population)이나 표본(sample)에서 평균이나 최빈값을 계산합니다.

mean()

데이터의 산술 평균(arithmetic mean) ( “average”).

fmean()

Fast, floating-point arithmetic mean, with optional weighting.

geometric_mean()

데이터의 기하 평균(geometric mean).

harmonic_mean()

데이터의 조화 평균(harmonic mean).

kde()

Estimate the probability density distribution of the data.

kde_random()

Random sampling from the PDF generated by kde().

median()

데이터의 중앙값(median) (중간값).

median_low()

데이터의 낮은 중앙값(low median).

median_high()

데이터의 높은 중앙값(high median).

median_grouped()

Median (50th percentile) of grouped data.

mode()

이산(discrete) 또는 범주(nominal) 데이터의 단일 최빈값(mode) (가장 흔한 값)

multimode()

List of modes (most common values) of discrete or nominal data.

quantiles()

데이터를 같은 확률을 갖는 구간으로 나눕니다.

분산 측정

이 함수는 모집단이나 표본이 평균값에서 벗어나는 정도를 측정합니다.

pstdev()

데이터의 모집단 표준 편차(population standard deviation).

pvariance()

데이터의 모집단 분산(population variance).

stdev()

데이터의 표본 표준 편차(sample standard deviation).

variance()

데이터의 표본 분산(sample variance).

Statistics for relations between two inputs

These functions calculate statistics regarding relations between two inputs.

covariance()

Sample covariance for two variables.

correlation()

Pearson and Spearman’s correlation coefficients.

linear_regression()

Slope and intercept for simple linear regression.

함수 세부 사항

참고: 함수에 전달되는 데이터가 정렬될 필요는 없습니다. 하지만, 읽기 쉽도록 대부분 예제는 정렬된 시퀀스를 보여줍니다.

statistics.mean(data)

시퀀스나 이터러블일 수 있는 data의 표본 산술 평균을 반환합니다.

산술 평균은 데이터의 합을 데이터 포인트 수로 나눈 값입니다. 흔히 “평균”이라고 합니다만, 많은 수학적 평균 중 하나일 뿐입니다. 데이터의 중심 위치에 대한 측정(measure)입니다.

data가 비어 있으면, StatisticsError가 발생합니다.

사용 예:

>>> mean([1, 2, 3, 4, 4])
2.8
>>> mean([-1.0, 2.5, 3.25, 5.75])
2.625

>>> from fractions import Fraction as F
>>> mean([F(3, 7), F(1, 21), F(5, 3), F(1, 3)])
Fraction(13, 21)

>>> from decimal import Decimal as D
>>> mean([D("0.5"), D("0.75"), D("0.625"), D("0.375")])
Decimal('0.5625')

참고

The mean is strongly affected by outliers [https://en.wikipedia.org/wiki/Outlier] and is not necessarily a typical example of the data points. For a more robust, although less efficient, measure of central tendency [https://en.wikipedia.org/wiki/Central_tendency], see median().

표본 평균은 실제 모집단 평균의 편향되지 않은(unbiased) 추정치를 제공합니다. 즉, 가능한 모든 표본에 대해 평균을 취하면, mean(sample)은 전체 모집단의 실제 평균에 수렴합니다. data가 표본이 아닌 전체 모집단을 나타낸다면, mean(data)는 실제 모집단 평균 μ를 계산하는 것과 동등합니다.

statistics.fmean(data, weights=None)

data를 float로 변환하고 산술 평균을 계산합니다.

mean() 함수보다 빠르게 실행되며 항상 float를 반환합니다. data는 시퀀스나 이터러블일 수 있습니다. 입력 data가 비어 있으면 StatisticsError를 발생시킵니다.

>>> fmean([3.5, 4.0, 5.25])
4.25

Optional weighting is supported. For example, a professor assigns a grade for a course by weighting quizzes at 20%, homework at 20%, a midterm exam at 30%, and a final exam at 30%:

>>> grades = [85, 92, 83, 91]
>>> weights = [0.20, 0.20, 0.30, 0.30]
>>> fmean(grades, weights)
87.6

If weights is supplied, it must be the same length as the data or a ValueError will be raised.

Added in version 3.8.

버전 3.11에서 변경: Added support for weights.

statistics.geometric_mean(data)

data를 float로 변환하고 기하 평균(geometric mean)을 계산합니다.

기하 평균은 값의 곱을 사용하는 data의 중심 경향(central tendency)이나 대표값(typical value)을 나타냅니다 (합을 사용하는 산술 평균과 달리).

입력 data가 비어 있거나, 0을 포함하거나, 음수 값을 포함하면 StatisticsError를 발생시킵니다. data는 시퀀스나 이터러블일 수 있습니다.

정확한 결과를 얻기 위해 특별한 노력을 기울이지는 않습니다. (하지만, 향후 변경될 수 있습니다.)

>>> round(geometric_mean([54, 24, 36]), 1)
36.0

Added in version 3.8.

statistics.harmonic_mean(data, weights=None)

Return the harmonic mean of data, a sequence or iterable of real-valued numbers. If weights is omitted or None, then equal weighting is assumed.

The harmonic mean is the reciprocal of the arithmetic mean() of the reciprocals of the data. For example, the harmonic mean of three values a, b and c will be equivalent to 3/(1/a + 1/b + 1/c). If one of the values is zero, the result will be zero.

The harmonic mean is a type of average, a measure of the central location of the data. It is often appropriate when averaging ratios or rates, for example speeds.

자동차가 40km/hr로 10km를 주행한 다음, 60km/hr로 10km를 주행한다고 가정해 봅시다. 평균 속도는 얼마입니까?

>>> harmonic_mean([40, 60])
48.0

Suppose a car travels 40 km/hr for 5 km, and when traffic clears, speeds-up to 60 km/hr for the remaining 30 km of the journey. What is the average speed?

>>> harmonic_mean([40, 60], weights=[5, 30])
56.0

StatisticsError is raised if data is empty, any element is less than zero, or if the weighted sum isn’t positive.

현재 알고리즘은 입력에서 0을 만나면 조기 종료됩니다. 이는 후속 입력의 유효성을 검사하지 않았음을 의미합니다. (이 동작은 나중에 변경될 수 있습니다.)

Added in version 3.6.

버전 3.10에서 변경: Added support for weights.

statistics.kde(data, h, kernel='normal', *, cumulative=False)

Kernel Density Estimation (KDE) [https://www.itm-conferences.org/articles/itmconf/pdf/2018/08/itmconf_sam2018_00037.pdf]: Create a continuous probability density function or cumulative distribution function from discrete samples.

The basic idea is to smooth the data using a kernel function [https://en.wikipedia.org/wiki/Kernel_(statistics)]. to help draw inferences about a population from a sample.

The degree of smoothing is controlled by the scaling parameter h which is called the bandwidth. Smaller values emphasize local features while larger values give smoother results.

The kernel determines the relative weights of the sample data points. Generally, the choice of kernel shape does not matter as much as the more influential bandwidth smoothing parameter.

Kernels that give some weight to every sample point include normal (gauss), logistic, and sigmoid.

Kernels that only give weight to sample points within the bandwidth include rectangular (uniform), triangular, parabolic (epanechnikov), quartic (biweight), triweight, and cosine.

If cumulative is true, will return a cumulative distribution function.

A StatisticsError will be raised if the data sequence is empty.

Wikipedia has an example [https://en.wikipedia.org/wiki/Kernel_density_estimation#Example] where we can use kde() to generate and plot a probability density function estimated from a small sample:

>>> sample = [-2.1, -1.3, -0.4, 1.9, 5.1, 6.2]
>>> f_hat = kde(sample, h=1.5)
>>> xarr = [i/100 for i in range(-750, 1100)]
>>> yarr = [f_hat(x) for x in xarr]

The points in xarr and yarr can be used to make a PDF plot:

Added in version 3.13.

statistics.kde_random(data, h, kernel='normal', *, seed=None)

Return a function that makes a random selection from the estimated probability density function produced by kde(data, h, kernel).

Providing a seed allows reproducible selections. In the future, the values may change slightly as more accurate kernel inverse CDF estimates are implemented. The seed may be an integer, float, str, or bytes.

A StatisticsError will be raised if the data sequence is empty.

Continuing the example for kde(), we can use kde_random() to generate new random selections from an estimated probability density function:

>>> data = [-2.1, -1.3, -0.4, 1.9, 5.1, 6.2]
>>> rand = kde_random(data, h=1.5, seed=8675309)
>>> new_selections = [rand() for i in range(10)]
>>> [round(x, 1) for x in new_selections]
[0.7, 6.2, 1.2, 6.9, 7.0, 1.8, 2.5, -0.5, -1.8, 5.6]

Added in version 3.13.

statistics.median(data)

일반적인 “중간 2개의 평균” 방법을 사용하여, 숫자 data의 중앙값(중간값)을 반환합니다. data가 비어 있으면, StatisticsError가 발생합니다. data는 시퀀스나 이터러블일 수 있습니다.

중앙값은 중심 위치에 대한 강인한 측정이며, 특이치가 있을 때 영향을 덜 받습니다. 데이터 포인트 수가 홀수면, 가운데 데이터 포인트가 반환됩니다:

>>> median([1, 3, 5])
3

데이터 포인트 수가 짝수면, 중앙값은 두 가운데 값의 평균을 취하여 보간됩니다:

>>> median([1, 3, 5, 7])
4.0

데이터가 이산(discrete)적이고, 중앙값이 실제 데이터 포인트가 아니라도 상관없을 때 적합합니다.

데이터가 순서는 있지만 (대소 비교 지원) 숫자가 아니면 (덧셈을 지원하지 않음), 대신 median_low()나 median_high()를 사용하는 것을 고려하십시오.

statistics.median_low(data)

숫자 데이터의 낮은 중앙값을 반환합니다. data가 비어 있으면 StatisticsError가 발생합니다. data는 시퀀스나 이터러블일 수 있습니다.

낮은 중앙값은 항상 데이터 세트의 멤버입니다. 데이터 포인트 수가 홀수이면 중간값이 반환됩니다. 짝수이면, 두 중간값 중 작은 값이 반환됩니다.

>>> median_low([1, 3, 5])
3
>>> median_low([1, 3, 5, 7])
3

데이터가 이산(discrete)적이고 보간된 값이 아닌 실제 데이터 포인트를 중앙값으로 선호할 때 낮은 중앙값을 사용하십시오.

statistics.median_high(data)

데이터의 높은 중앙값을 반환합니다. data가 비어 있으면 StatisticsError가 발생합니다. data는 시퀀스나 이터러블일 수 있습니다.

높은 중앙값은 항상 데이터 세트의 멤버입니다. 데이터 포인트 수가 홀수이면 중간값이 반환됩니다. 짝수이면, 두 중간값 중 큰 값이 반환됩니다.

>>> median_high([1, 3, 5])
3
>>> median_high([1, 3, 5, 7])
5

데이터가 이산(discrete)적이고 보간된 값이 아닌 실제 데이터 포인트를 중앙값으로 선호할 때 높은 중앙값을 사용하십시오.

statistics.median_grouped(data, interval=1.0)

Estimates the median for numeric data that has been grouped or binned [https://en.wikipedia.org/wiki/Data_binning] around the midpoints of consecutive, fixed-width intervals.

The data can be any iterable of numeric data with each value being exactly the midpoint of a bin. At least one value must be present.

The interval is the width of each bin.

For example, demographic information may have been summarized into consecutive ten-year age groups with each group being represented by the 5-year midpoints of the intervals:

>>> from collections import Counter
>>> demographics = Counter({
...    25: 172,   # 20 to 30 years old
...    35: 484,   # 30 to 40 years old
...    45: 387,   # 40 to 50 years old
...    55:  22,   # 50 to 60 years old
...    65:   6,   # 60 to 70 years old
... })
...

The 50th percentile (median) is the 536th person out of the 1071 member cohort. That person is in the 30 to 40 year old age group.

The regular median() function would assume that everyone in the tricenarian age group was exactly 35 years old. A more tenable assumption is that the 484 members of that age group are evenly distributed between 30 and 40. For that, we use median_grouped():

>>> data = list(demographics.elements())
>>> median(data)
35
>>> round(median_grouped(data, interval=10), 1)
37.5

The caller is responsible for making sure the data points are separated by exact multiples of interval. This is essential for getting a correct result. The function does not check this precondition.

Inputs may be any numeric type that can be coerced to a float during the interpolation step.

statistics.mode(data)

이산(discrete)적이거나 범주(nominal)적인 data에서 가장 흔한 단일 데이터 포인트를 반환합니다. 최빈값(mode)은 (존재할 때) 가장 흔한 값이며 중심 위치의 측정으로 기능합니다.

같은 빈도의 여러 최빈값이 있으면, data에서 처음 발견된 첫 번째 값을 반환합니다. 여러 최빈값 중 가장 작거나 가장 큰 값이 필요하면 대신 min(multimode(data))나 max(multimode(data))를 사용하십시오. 입력 data가 비어 있으면, StatisticsError가 발생합니다.

mode는 이산 데이터를 가정하고 단일 값을 반환합니다. 이것이 학교에서 일반적으로 가르치는 최빈값의 표준적인 처리입니다:

>>> mode([1, 1, 2, 3, 3, 3, 3, 4])
3

최빈값은 범주(nominal)적 (숫자가 아닌) 데이터에도 적용되는 이 패키지에 있는 유일한 통계라는 점에서 특별합니다:

>>> mode(["red", "blue", "blue", "red", "green", "red", "red"])
'red'

Only hashable inputs are supported. To handle type set, consider casting to frozenset. To handle type list, consider casting to tuple. For mixed or nested inputs, consider using this slower quadratic algorithm that only depends on equality tests: max(data, key=data.count).

버전 3.8에서 변경: 이제 첫 번째 최빈값을 모드를 반환하여 다봉(multimodal) 데이터 세트를 처리합니다. 이전에는, 둘 이상의 최빈값이 발견되면 StatisticsError가 발생했습니다.

statistics.multimode(data)

data에서 먼저 발견되는 순서대로 가장 자주 등장하는 값의 리스트를 반환합니다. 여러 최빈값이 있으면 둘 이상의 결과를 반환하고, data가 비어 있으면 빈 리스트를 반환합니다:

>>> multimode('aabbbbccddddeeffffgg')
['b', 'd', 'f']
>>> multimode('')
[]

Added in version 3.8.

statistics.pstdev(data, mu=None)

모집단 표준 편차(모집단 분산의 제곱근)를 반환합니다. 인자와 기타 세부 사항은 pvariance()를 참조하십시오.

>>> pstdev([1.5, 2.5, 2.5, 2.75, 3.25, 4.75])
0.986893273527251

statistics.pvariance(data, mu=None)

실수 숫자의 비어있지 않은 시퀀스나 이터러블인 data의 모집단 분산을 반환합니다. 분산(또는 평균에 대한 이차 모멘트)은 데이터 변동성(퍼진 정도)의 측정입니다. 큰 분산은 데이터가 퍼져 있음을 나타냅니다; 작은 분산은 평균 주변에 군집되어 있음을 나타냅니다.

If the optional second argument mu is given, it should be the population mean of the data. It can also be used to compute the second moment around a point that is not the mean. If it is missing or None (the default), the arithmetic mean is automatically calculated.

이 함수를 사용하여 전체 모집단의 분산을 계산하십시오. 표본으로 분산을 추정하려면, 일반적으로 variance() 함수가 더 좋은 선택입니다.

data가 비어 있으면 StatisticsError를 발생시킵니다.

예:

>>> data = [0.0, 0.25, 0.25, 1.25, 1.5, 1.75, 2.75, 3.25]
>>> pvariance(data)
1.25

데이터의 평균을 이미 계산했다면, 재계산을 피하고자 선택적인 두 번째 인자 mu로 전달할 수 있습니다:

>>> mu = mean(data)
>>> pvariance(data, mu)
1.25

Decimal과 Fraction이 지원됩니다:

>>> from decimal import Decimal as D
>>> pvariance([D("27.5"), D("30.25"), D("30.25"), D("34.5"), D("41.75")])
Decimal('24.815')

>>> from fractions import Fraction as F
>>> pvariance([F(1, 4), F(5, 4), F(1, 2)])
Fraction(13, 72)

참고

전체 모집단으로 호출하면, 모집단 분산 σ²을 줍니다. 대신 표본으로 호출하면, 편향된(biased) 표본 분산 s²이 됩니다, N 자유도의 분산이라고도 합니다.

실제 모집단 평균 μ를 어떻게든 알고 있다면, 알려진 모집단 평균을 두 번째 인자로 지정해서, 이 함수를 사용하여 표본의 분산을 계산할 수 있습니다. 데이터 포인트가 모집단의 무작위 표본이면, 결과는 모집단 분산의 편향 없는(unbiased) 추정치가 됩니다.

statistics.stdev(data, xbar=None)

표본 표준 편차(표본 분산의 제곱근)를 반환합니다. 인자와 기타 세부 사항은 variance()를 참조하십시오.

>>> stdev([1.5, 2.5, 2.5, 2.75, 3.25, 4.75])
1.0810874155219827

statistics.variance(data, xbar=None)

적어도 두 개의 실수 숫자를 제공하는 이터러블인 data의 표본 분산을 반환합니다. 분산(또는 평균에 대한 이차 모멘트)은 데이터 변동성(퍼진 정도)의 측정입니다. 큰 분산은 데이터가 퍼져 있음을 나타냅니다; 작은 분산은 평균 주변에 군집되어 있음을 나타냅니다.

If the optional second argument xbar is given, it should be the sample mean of data. If it is missing or None (the default), the mean is automatically calculated.

데이터가 모집단의 표본이면 이 함수를 사용하십시오. 전체 모집단의 분산을 계산하려면, pvariance()를 참조하십시오.

data의 두 개 미만의 값을 갖고 있으면 StatisticsError를 발생시킵니다.

예:

>>> data = [2.75, 1.75, 1.25, 0.25, 0.5, 1.25, 3.5]
>>> variance(data)
1.3720238095238095

If you have already calculated the sample mean of your data, you can pass it as the optional second argument xbar to avoid recalculation:

>>> m = mean(data)
>>> variance(data, m)
1.3720238095238095

이 함수는 실제 평균을 xbar로 전달했는지 확인하지 않습니다. xbar에 임의의 값을 사용하면 결과가 유효하지 않거나 불가능한 값일 수 있습니다.

Decimal과 Fraction 값이 지원됩니다:

>>> from decimal import Decimal as D
>>> variance([D("27.5"), D("30.25"), D("30.25"), D("34.5"), D("41.75")])
Decimal('31.01875')

>>> from fractions import Fraction as F
>>> variance([F(1, 6), F(1, 2), F(5, 3)])
Fraction(67, 108)

참고

이것은 베셀 보정(Bessel’s correction)을 적용한 표본 분산 s² 입니다, N-1 자유도의 분산이라고도 합니다. 데이터 포인트가 대표적(예를 들어, 독립적이고 동일하게 분포된)이라면, 결과는 실제 모집단 분산의 편향 없는(unbiased) 추정치가 되어야 합니다.

실제 모집단 평균 μ를 어떻게든 알고 있다면 mu 매개 변수로 pvariance() 함수에 전달하여 표본의 분산을 구해야 합니다.

statistics.quantiles(data, *, n=4, method='exclusive')

data를 같은 확률을 갖는 n 개의 연속 구간으로 나눕니다. 구간을 분할하는 n - 1개의 절단 점(cut point) 리스트를 반환합니다.

사분위는 n을 4로 설정하십시오 (기본값). 십분위는 n을 10으로 설정하십시오. 백분위는 n을 100으로 설정하십시오. 그러면 data를 100개의 같은 크기 그룹으로 분할하는 99개의 절단 점이 제공됩니다. n이 1 미만이면 StatisticsError를 발생시킵니다.

The data can be any iterable containing sample data. For meaningful results, the number of data points in data should be larger than n. Raises StatisticsError if there is not at least one data point.

절단 점은 가장 가까운 두 개의 데이터 포인트에서 선형 보간됩니다. 예를 들어, 절단 점이 두 표본 값 100과 112 사이의 거리로 1/3 지점에 해당하면, 절단 점은 104로 평가됩니다.

균등 분위(quantile) 계산 방법(method)은 data가 모집단에서 가능한 최젓값과 최곳값을 포함하는지 제외하는지에 따라 달라질 수 있습니다.

기본 method는 “exclusive”이며, 표본에서 발견되는 것보다 더 극단적인 값을 가질 수 있는 모집단에서 표본 추출된 데이터에 사용됩니다. m 개의 정렬된 데이터 포인트의 i-번째 아래로 떨어지는 모집단 부분은 i / (m + 1)로 계산됩니다. 9개의 표본 값을 주면, 이 방법은 그들을 정렬한 다음, 다음과 같은 백분위를 할당합니다: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%.

method를 “inclusive”로 설정하는 것은 모집단 데이터를 기술하거나 모집단의 가장 극단적인 값을 포함하는 것으로 알려진 표본에 사용됩니다. data의 최솟값은 0번째 백분위 수로 취급되고 최댓값은 100번째 백분위 수로 취급됩니다. m 개의 정렬된 데이터 포인트의 i-번째 아래로 떨어지는 모집단 부분은 (i - 1) / (m - 1)로 계산됩니다. 11개의 표본 값을 주면, 이 방법은 그들을 정렬한 다음, 다음과 같은 백분위를 할당합니다: 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%.

# Decile cut points for empirically sampled data
>>> data = [105, 129, 87, 86, 111, 111, 89, 81, 108, 92, 110,
...         100, 75, 105, 103, 109, 76, 119, 99, 91, 103, 129,
...         106, 101, 84, 111, 74, 87, 86, 103, 103, 106, 86,
...         111, 75, 87, 102, 121, 111, 88, 89, 101, 106, 95,
...         103, 107, 101, 81, 109, 104]
>>> [round(q, 1) for q in quantiles(data, n=10)]
[81.0, 86.2, 89.0, 99.4, 102.5, 103.6, 106.0, 109.8, 111.0]

Added in version 3.8.

버전 3.13에서 변경: No longer raises an exception for an input with only a single data point. This allows quantile estimates to be built up one sample point at a time becoming gradually more refined with each new data point.

statistics.covariance(x, y, /)

Return the sample covariance of two inputs x and y. Covariance is a measure of the joint variability of two inputs.

Both inputs must be of the same length (no less than two), otherwise StatisticsError is raised.

예:

>>> x = [1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> y = [1, 2, 3, 1, 2, 3, 1, 2, 3]
>>> covariance(x, y)
0.75
>>> z = [9, 8, 7, 6, 5, 4, 3, 2, 1]
>>> covariance(x, z)
-7.5
>>> covariance(z, x)
-7.5

Added in version 3.10.

statistics.correlation(x, y, /, *, method='linear')

Return the Pearson’s correlation coefficient [https://en.wikipedia.org/wiki/Pearson_correlation_coefficient] for two inputs. Pearson’s correlation coefficient r takes values between -1 and +1. It measures the strength and direction of a linear relationship.

If method is “ranked”, computes Spearman’s rank correlation coefficient [https://en.wikipedia.org/wiki/Spearman%27s_rank_correlation_coefficient] for two inputs. The data is replaced by ranks. Ties are averaged so that equal values receive the same rank. The resulting coefficient measures the strength of a monotonic relationship.

Spearman’s correlation coefficient is appropriate for ordinal data or for continuous data that doesn’t meet the linear proportion requirement for Pearson’s correlation coefficient.

Both inputs must be of the same length (no less than two), and need not to be constant, otherwise StatisticsError is raised.

Example with Kepler’s laws of planetary motion [https://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion]:

>>> # Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and  Neptune
>>> orbital_period = [88, 225, 365, 687, 4331, 10_756, 30_687, 60_190]    # days
>>> dist_from_sun = [58, 108, 150, 228, 778, 1_400, 2_900, 4_500] # million km

>>> # Show that a perfect monotonic relationship exists
>>> correlation(orbital_period, dist_from_sun, method='ranked')
1.0

>>> # Observe that a linear relationship is imperfect
>>> round(correlation(orbital_period, dist_from_sun), 4)
0.9882

>>> # Demonstrate Kepler's third law: There is a linear correlation
>>> # between the square of the orbital period and the cube of the
>>> # distance from the sun.
>>> period_squared = [p * p for p in orbital_period]
>>> dist_cubed = [d * d * d for d in dist_from_sun]
>>> round(correlation(period_squared, dist_cubed), 4)
1.0

Added in version 3.10.

버전 3.12에서 변경: Added support for Spearman’s rank correlation coefficient.

statistics.linear_regression(x, y, /, *, proportional=False)

Return the slope and intercept of simple linear regression [https://en.wikipedia.org/wiki/Simple_linear_regression] parameters estimated using ordinary least squares. Simple linear regression describes the relationship between an independent variable x and a dependent variable y in terms of this linear function:

y = slope * x + intercept + noise

where slope and intercept are the regression parameters that are estimated, and noise represents the variability of the data that was not explained by the linear regression (it is equal to the difference between predicted and actual values of the dependent variable).

Both inputs must be of the same length (no less than two), and the independent variable x cannot be constant; otherwise a StatisticsError is raised.

For example, we can use the release dates of the Monty Python films [https://en.wikipedia.org/wiki/Monty_Python#Films] to predict the cumulative number of Monty Python films that would have been produced by 2019 assuming that they had kept the pace.

>>> year = [1971, 1975, 1979, 1982, 1983]
>>> films_total = [1, 2, 3, 4, 5]
>>> slope, intercept = linear_regression(year, films_total)
>>> round(slope * 2019 + intercept)
16

If proportional is true, the independent variable x and the dependent variable y are assumed to be directly proportional. The data is fit to a line passing through the origin. Since the intercept will always be 0.0, the underlying linear function simplifies to:

y = slope * x + noise

Continuing the example from correlation(), we look to see how well a model based on major planets can predict the orbital distances for dwarf planets:

>>> model = linear_regression(period_squared, dist_cubed, proportional=True)
>>> slope = model.slope

>>> # Dwarf planets:   Pluto,  Eris,    Makemake, Haumea, Ceres
>>> orbital_periods = [90_560, 204_199, 111_845, 103_410, 1_680]  # days
>>> predicted_dist = [math.cbrt(slope * (p * p)) for p in orbital_periods]
>>> list(map(round, predicted_dist))
[5912, 10166, 6806, 6459, 414]

>>> [5_906, 10_152, 6_796, 6_450, 414]  # actual distance in million km
[5906, 10152, 6796, 6450, 414]

Added in version 3.10.

버전 3.11에서 변경: Added support for proportional.

예외

하나의 예외가 정의됩니다:

exception statistics.StatisticsError

통계 관련 예외를 위한 ValueError의 서브 클래스.

NormalDist 객체

NormalDist는 무작위 변수 [http://www.stat.yale.edu/Courses/1997-98/101/ranvar.htm]의 정규 분포를 만들고 조작하기 위한 도구입니다. 데이터 측정의 평균과 표준 편차를 단일 엔티티로 취급하는 클래스입니다.

정규 분포는 중심 극한 정리(Central Limit Theorem) [https://en.wikipedia.org/wiki/Central_limit_theorem]에서 도출되며 통계에서 광범위하게 응용됩니다.

class statistics.NormalDist(mu=0.0, sigma=1.0)

mu가 산술 평균 [https://en.wikipedia.org/wiki/Arithmetic_mean]을 나타내고 sigma가 표준 편차 [https://en.wikipedia.org/wiki/Standard_deviation]를 나타내는 새 NormalDist 객체를 반환합니다.

sigma가 음수이면 StatisticsError를 발생시킵니다.

mean

정규 분포의 산술 평균 [https://en.wikipedia.org/wiki/Arithmetic_mean]에 대한 읽기 전용 프로퍼티.

median

정규 분포의 중앙값 [https://en.wikipedia.org/wiki/Median]에 대한 읽기 전용 프로퍼티.

mode

정규 분포의 최빈값 [https://en.wikipedia.org/wiki/Mode_(statistics)]에 대한 읽기 전용 프로퍼티.

stdev

정규 분포의 표준 편차 [https://en.wikipedia.org/wiki/Standard_deviation]에 대한 읽기 전용 프로퍼티.

variance

정규 분포의 분산 [https://en.wikipedia.org/wiki/Variance]에 대한 읽기 전용 프로퍼티. 표준 편차의 제곱과 같습니다.

classmethod from_samples(data)

fmean()과 stdev()를 사용해서 data에서 추정된 mu와 sigma 매개 변수로 정규 분포 인스턴스를 만듭니다.

data는 임의의 이터러블일 수 있으며 float 형으로 변환될 수 있는 값으로 구성되어야 합니다. data가 두 개 이상의 값을 포함하지 않으면 StatisticsError를 발생시키는데, 중심 값을 추정하는 데 적어도 한 점이 필요하고 분산을 추정하는 데 적어도 두 점이 필요하기 때문입니다.

samples(n, *, seed=None)

주어진 평균과 표준 편차로 n 개의 무작위 표본을 생성합니다. float 값의 list를 반환합니다.

seed가 제공되면, 하부 난수 생성기의 새 인스턴스를 만듭니다. 이는 다중 스레딩 문맥에서도, 재현 가능한 결과를 만드는 데 유용합니다.

버전 3.13에서 변경.

Switched to a faster algorithm. To reproduce samples from previous versions, use random.seed() and random.gauss().

pdf(x)

확률 밀도 함수(pdf) [https://en.wikipedia.org/wiki/Probability_density_function]를 사용하여, 무작위 변수 X가 주어진 값 x에 가까울 상대적 가능도(likelihood)를 계산합니다. 수학적으로, 비율 P(x <= X < x+dx) / dx의 dx가 0으로 접근할 때의 극한값입니다.

The relative likelihood is computed as the probability of a sample occurring in a narrow range divided by the width of the range (hence the word “density”). Since the likelihood is relative to other points, its value can be greater than 1.0.

cdf(x)

누적 분포 함수 (cdf) [https://en.wikipedia.org/wiki/Cumulative_distribution_function]를 사용하여, 무작위 변수 X가 x보다 작거나 같을 확률을 계산합니다. 수학적으로, P(X <= x)라고 씁니다.

inv_cdf(p)

Compute the inverse cumulative distribution function, also known as the quantile function [https://en.wikipedia.org/wiki/Quantile_function] or the percent-point [https://web.archive.org/web/20190203145224/https://www.statisticshowto.datasciencecentral.com/inverse-distribution-function/] function. Mathematically, it is written x : P(X <= x) = p.

변수가 x보다 작거나 같을 확률이 주어진 확률 p와 같아지도록 하는 무작위 변수 X의 값 x를 찾습니다.

overlap(other)

두 정규 확률 분포 간의 일치를 측정합니다. 두 확률 밀도 함수가 겹치는 영역의 면적 [https://www.rasch.org/rmt/rmt101r.htm]을 제공하는 0.0과 1.0 사이의 값을 반환합니다.

quantiles(n=4)

정규 분포를 같은 확률을 갖는 n 개의 연속 구간으로 나눕니다. 구간을 분할하는 (n - 1)개의 절단 점(cut point) 리스트를 반환합니다.

사분위는 n을 4로 설정하십시오 (기본값). 십분위는 n을 10으로 설정하십시오. 백분위는 n을 100으로 설정하십시오, 그러면 정규 분포를 100개의 같은 크기 그룹으로 분할하는 99개의 절단 점이 제공됩니다.

zscore(x)

정규 분포의 평균 위나 아래의 표준 편차 수로 x를 설명하는 표준 점수(Standard Score) [https://www.statisticshowto.com/probability-and-statistics/z-score/]를 계산합니다: (x - mean) / stdev.

Added in version 3.9.

NormalDist의 인스턴스는 상수에 의한 덧셈, 뺄셈, 곱셈 및 나눗셈을 지원합니다. 이러한 연산은 이동(translation)과 확대(scaling)에 사용됩니다. 예를 들면:

>>> temperature_february = NormalDist(5, 2.5)             # Celsius
>>> temperature_february * (9/5) + 32                     # Fahrenheit
NormalDist(mu=41.0, sigma=4.5)

상수를 NormalDist의 인스턴스로 나누는 것은 결과가 정규 분포가 되지 않기 때문에 지원되지 않습니다.

정규 분포는 독립 변수의 가산(additive) 효과에서 발생하므로, 두 독립된 정규 분포 무작위 변수를 더하고 빼는 것 [https://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables]은 NormalDist의 인스턴스로 나타낼 수 있습니다. 예를 들면:

>>> birth_weights = NormalDist.from_samples([2.5, 3.1, 2.1, 2.4, 2.7, 3.5])
>>> drug_effects = NormalDist(0.4, 0.15)
>>> combined = birth_weights + drug_effects
>>> round(combined.mean, 1)
3.1
>>> round(combined.stdev, 1)
0.5

Added in version 3.8.

Examples and Recipes

Classic probability problems

NormalDist는 고전적인 확률 문제를 쉽게 해결합니다.

예를 들어, 점수가 평균 1060이고 표준 편차가 195인 정규 분포를 보이는 SAT 시험의 역사적 데이터 [https://nces.ed.gov/programs/digest/d17/tables/dt17_226.40.asp]를 줄 때, 시험 점수가 1100에서 1200 사이인 학생들의 백분율을 결정하십시오. 가장 가까운 정수로 반올림하십시오:

>>> sat = NormalDist(1060, 195)
>>> fraction = sat.cdf(1200 + 0.5) - sat.cdf(1100 - 0.5)
>>> round(fraction * 100.0, 1)
18.4

SAT 점수의 사분위 수(quartiles) [https://en.wikipedia.org/wiki/Quartile]와 십분위 수(deciles) [https://en.wikipedia.org/wiki/Decile]를 찾으십시오:

>>> list(map(round, sat.quantiles()))
[928, 1060, 1192]
>>> list(map(round, sat.quantiles(n=10)))
[810, 896, 958, 1011, 1060, 1109, 1162, 1224, 1310]

Monte Carlo inputs for simulations

To estimate the distribution for a model that isn’t easy to solve analytically, NormalDist can generate input samples for a Monte Carlo simulation [https://en.wikipedia.org/wiki/Monte_Carlo_method]:

>>> def model(x, y, z):
...     return (3*x + 7*x*y - 5*y) / (11 * z)
...
>>> n = 100_000
>>> X = NormalDist(10, 2.5).samples(n, seed=3652260728)
>>> Y = NormalDist(15, 1.75).samples(n, seed=4582495471)
>>> Z = NormalDist(50, 1.25).samples(n, seed=6582483453)
>>> quantiles(map(model, X, Y, Z))
[1.4591308524824727, 1.8035946855390597, 2.175091447274739]

Approximating binomial distributions

Normal distributions can be used to approximate Binomial distributions [https://mathworld.wolfram.com/BinomialDistribution.html] when the sample size is large and when the probability of a successful trial is near 50%.

예를 들어, 오픈 소스 회의에는 750명의 참석자와 500명 정원의 방 두 개가 있습니다. 파이썬과 루비에 대한 발표가 있습니다. 이전 회의에서는, 참석자의 65%가 파이썬 발표를 듣는 것을 선호했습니다. 모집단 선호도가 변경되지 않았다고 가정할 때, 파이썬 방이 정원 한도 내에 머무를 확률은 얼마입니까?

>>> n = 750             # Sample size
>>> p = 0.65            # Preference for Python
>>> q = 1.0 - p         # Preference for Ruby
>>> k = 500             # Room capacity

>>> # Approximation using the cumulative normal distribution
>>> from math import sqrt
>>> round(NormalDist(mu=n*p, sigma=sqrt(n*p*q)).cdf(k + 0.5), 4)
0.8402

>>> # Exact solution using the cumulative binomial distribution
>>> from math import comb, fsum
>>> round(fsum(comb(n, r) * p**r * q**(n-r) for r in range(k+1)), 4)
0.8402

>>> # Approximation using a simulation
>>> from random import seed, binomialvariate
>>> seed(8675309)
>>> mean(binomialvariate(n, p) <= k for i in range(10_000))
0.8406

Naive bayesian classifier

정규 분포는 기계 학습 문제에서 흔히 등장합니다.

Wikipedia has a nice example of a Naive Bayesian Classifier [https://en.wikipedia.org/wiki/Naive_Bayes_classifier#Person_classification]. The challenge is to predict a person’s gender from measurements of normally distributed features including height, weight, and foot size.

우리는 8명을 측정한 훈련 데이터 집합을 받았습니다. 측정값은 정규 분포로 가정되므로, NormalDist로 데이터를 요약합니다:

>>> height_male = NormalDist.from_samples([6, 5.92, 5.58, 5.92])
>>> height_female = NormalDist.from_samples([5, 5.5, 5.42, 5.75])
>>> weight_male = NormalDist.from_samples([180, 190, 170, 165])
>>> weight_female = NormalDist.from_samples([100, 150, 130, 150])
>>> foot_size_male = NormalDist.from_samples([12, 11, 12, 10])
>>> foot_size_female = NormalDist.from_samples([6, 8, 7, 9])

다음으로, 피처 측정은 알려졌지만, 성별을 모르는 새로운 사람을 만납니다:

>>> ht = 6.0        # height
>>> wt = 130        # weight
>>> fs = 8          # foot size

남성이나 여성일 50%의 사전 확률(prior probability) [https://en.wikipedia.org/wiki/Prior_probability]로 시작하여, 사전 확률에 주어진 성별이 피처 측정을 줄 우도(likelihood)를 곱해서 사후 확률(posterior)을 계산합니다.:

>>> prior_male = 0.5
>>> prior_female = 0.5
>>> posterior_male = (prior_male * height_male.pdf(ht) *
...                   weight_male.pdf(wt) * foot_size_male.pdf(fs))

>>> posterior_female = (prior_female * height_female.pdf(ht) *
...                     weight_female.pdf(wt) * foot_size_female.pdf(fs))

최종 예측은 가장 큰 사후 확률(posterior)이 됩니다. 이것을 최대 사후 확률(maximum a posteriori) [https://en.wikipedia.org/wiki/Maximum_a_posteriori_estimation] 또는 MAP이라고 합니다.:

>>> 'male' if posterior_male > posterior_female else 'female'
'female'

함수형 프로그래밍 모듈

이 장에서 설명하는 모듈은 함수형 프로그래밍 스타일을 지원하는 함수 및 클래스와 콜러블에 대한 일반 연산을 제공합니다.

이 장에서는 다음 모듈에 관해 설명합니다:

itertools — Functions creating iterators for efficient looping

Itertool Functions

accumulate()

batched()

chain()

from_iterable()

combinations()

combinations_with_replacement()

compress()

count()

cycle()

dropwhile()

filterfalse()

groupby()

islice()

pairwise()

permutations()

product()

repeat()

starmap()

takewhile()

tee()

zip_longest()

Itertools 조리법

functools — Higher-order functions and operations on callable objects

cache()

cached_property()

cmp_to_key()

lru_cache()

total_ordering()

Placeholder

partial()

partialmethod

reduce()

singledispatch()

singledispatchmethod

update_wrapper()

wraps()

partial 객체

func

args

keywords

operator — Standard operators as functions

lt()

le()

eq()

ne()

ge()

gt()

__lt__()

__le__()

__eq__()

__ne__()

__ge__()

__gt__()

not_()

__not__()

truth()

is_()

is_not()

is_none()

is_not_none()

abs()

__abs__()

add()

__add__()

and_()

__and__()

floordiv()

__floordiv__()

index()

__index__()

inv()

invert()

__inv__()

__invert__()

lshift()

__lshift__()

mod()

__mod__()

mul()

__mul__()

matmul()

__matmul__()

neg()

__neg__()

or_()

__or__()

pos()

__pos__()

pow()

__pow__()

rshift()

__rshift__()

sub()

__sub__()

truediv()

__truediv__()

xor()

__xor__()

concat()

__concat__()

contains()

__contains__()

countOf()

delitem()

__delitem__()

getitem()

__getitem__()

indexOf()

setitem()

__setitem__()

length_hint()

call()

__call__()

attrgetter()

itemgetter()

methodcaller()

연산자를 함수에 매핑하기

제자리 연산자

iadd()

__iadd__()

iand()

__iand__()

iconcat()

__iconcat__()

ifloordiv()

__ifloordiv__()

ilshift()

__ilshift__()

imod()

__imod__()

imul()

__imul__()

imatmul()

__imatmul__()

ior()

__ior__()

ipow()

__ipow__()

irshift()

__irshift__()

isub()

__isub__()

itruediv()

__itruediv__()

ixor()

__ixor__()

itertools — Functions creating iterators for efficient looping

이 모듈은 APL, Haskell 및 SML의 구성물들에서 영감을 얻은 여러 이터레이터 빌딩 블록을 구현합니다. 각각을 파이썬에 적합한 형태로 개선했습니다.

이 모듈은 자체적으로 혹은 조합하여 유용한 빠르고 메모리 효율적인 도구의 핵심 집합을 표준화합니다. 함께 모여, 순수 파이썬에서 간결하고 효율적으로 특수화된 도구를 구성할 수 있도록 하는 “이터레이터 대수(iterator algebra)”를 형성합니다.

예를 들어, SML은 테이블 화 도구를 제공합니다: 시퀀스 f(0), f(1), ...를 생성하는 tabulate(f). map()과 count()를 결합하여 map(f, count())를 형성해서 파이썬에서도 같은 효과를 얻을 수 있습니다.

These tools and their built-in counterparts also work well with the high-speed functions in the operator module. For example, the multiplication operator can be mapped across two vectors to form an efficient dot-product: sum(starmap(operator.mul, zip(vec1, vec2, strict=True))).

무한 이터레이터:

이터레이터

인자

결과

예

count()

[start[, step]]

start, start+step, start+2*step, …

count(10) → 10 11 12 13 14 ...

cycle()

p

p0, p1, … plast, p0, p1, …

cycle('ABCD') → A B C D A B C D ...

repeat()

elem [,n]

elem, elem, elem, … 끝없이 또는 최대 n 번

repeat(10, 3) → 10 10 10

가장 짧은 입력 시퀀스에서 종료되는 이터레이터:

이터레이터

인자

결과

예

accumulate()

p [,func]

p0, p0+p1, p0+p1+p2, …

accumulate([1,2,3,4,5]) → 1 3 6 10 15

batched()

p, n

(p0, p1, …, p_n-1), …

batched('ABCDEFG', n=3) → ABC DEF G

chain()

p, q, …

p0, p1, … plast, q0, q1, …

chain('ABC', 'DEF') → A B C D E F

chain.from_iterable()

iterable

p0, p1, … plast, q0, q1, …

chain.from_iterable(['ABC', 'DEF']) → A B C D E F

compress()

data, selectors

(d[0] if s[0]), (d[1] if s[1]), …

compress('ABCDEF', [1,0,1,0,1,1]) → A C E F

dropwhile()

predicate, seq

seq[n], seq[n+1], starting when predicate fails

dropwhile(lambda x: x<5, [1,4,6,3,8]) → 6 3 8

filterfalse()

predicate, seq

elements of seq where predicate(elem) fails

filterfalse(lambda x: x<5, [1,4,6,3,8]) → 6 8

groupby()

iterable[, key]

key(v)의 값으로 그룹화된 서브 이터레이터들

groupby(['A','B','DEF'], len) → (1, A B) (3, DEF)

islice()

seq, [start,] stop [, step]

seq[start:stop:step]의 요소들

islice('ABCDEFG', 2, None) → C D E F G

pairwise()

iterable

(p[0], p[1]), (p[1], p[2])

pairwise('ABCDEFG') → AB BC CD DE EF FG

starmap()

func, seq

func(*seq[0]), func(*seq[1]), …

starmap(pow, [(2,5), (3,2), (10,3)]) → 32 9 1000

takewhile()

predicate, seq

seq[0], seq[1], until predicate fails

takewhile(lambda x: x<5, [1,4,6,3,8]) → 1 4

tee()

it, n

it1, it2, … itn 하나의 이터레이터를 n개의 이터레이터로 나눕니다

tee('ABC', 2) → A B C, A B C

zip_longest()

p, q, …

(p[0], q[0]), (p[1], q[1]), …

zip_longest('ABCD', 'xy', fillvalue='-') → Ax By C- D-

조합형 이터레이터:

이터레이터

인자

결과

product()

p, q, … [repeat=1]

데카르트 곱(cartesian product), 중첩된 for 루프와 동등합니다

permutations()

p[, r]

r-길이 튜플들, 모든 가능한 순서, 반복되는 요소 없음

combinations()

p, r

r-길이 튜플들, 정렬된 순서, 반복되는 요소 없음

combinations_with_replacement()

p, r

r-길이 튜플들, 정렬된 순서, 반복되는 요소 있음

예

결과

product('ABCD', repeat=2)

AA AB AC AD BA BB BC BD CA CB CC CD DA DB DC DD

permutations('ABCD', 2)

AB AC AD BA BC BD CA CB CD DA DB DC

combinations('ABCD', 2)

AB AC AD BC BD CD

combinations_with_replacement('ABCD', 2)

AA AB AC AD BB BC BD CC CD DD

Itertool Functions

The following functions all construct and return iterators. Some provide streams of infinite length, so they should only be accessed by functions or loops that truncate the stream.

itertools.accumulate(iterable[, function, *, initial=None])

Make an iterator that returns accumulated sums or accumulated results from other binary functions.

The function defaults to addition. The function should accept two arguments, an accumulated total and a value from the iterable.

If an initial value is provided, the accumulation will start with that value and the output will have one more element than the input iterable.

대략 다음과 동등합니다:

def accumulate(iterable, function=operator.add, *, initial=None):
    'Return running totals'
    # accumulate([1,2,3,4,5]) → 1 3 6 10 15
    # accumulate([1,2,3,4,5], initial=100) → 100 101 103 106 110 115
    # accumulate([1,2,3,4,5], operator.mul) → 1 2 6 24 120

    iterator = iter(iterable)
    total = initial
    if initial is None:
        try:
            total = next(iterator)
        except StopIteration:
            return

    yield total
    for element in iterator:
        total = function(total, element)
        yield total

To compute a running minimum, set function to min(). For a running maximum, set function to max(). Or for a running product, set function to operator.mul(). To build an amortization table [https://www.ramseysolutions.com/real-estate/amortization-schedule], accumulate the interest and apply payments:

>>> data = [3, 4, 6, 2, 1, 9, 0, 7, 5, 8]
>>> list(accumulate(data, max))              # running maximum
[3, 4, 6, 6, 6, 9, 9, 9, 9, 9]
>>> list(accumulate(data, operator.mul))     # running product
[3, 12, 72, 144, 144, 1296, 0, 0, 0, 0]

# Amortize a 5% loan of 1000 with 10 annual payments of 90
>>> update = lambda balance, payment: round(balance * 1.05) - payment
>>> list(accumulate(repeat(90, 10), update, initial=1_000))
[1000, 960, 918, 874, 828, 779, 728, 674, 618, 559, 497]

최종 누적값만 반환하는 유사한 함수에 대해서는 functools.reduce()를 참조하십시오.

Added in version 3.2.

버전 3.3에서 변경: Added the optional function parameter.

버전 3.8에서 변경: 선택적 initial 매개 변수를 추가했습니다.

itertools.batched(iterable, n, *, strict=False)

Batch data from the iterable into tuples of length n. The last batch may be shorter than n.

If strict is true, will raise a ValueError if the final batch is shorter than n.

Loops over the input iterable and accumulates data into tuples up to size n. The input is consumed lazily, just enough to fill a batch. The result is yielded as soon as the batch is full or when the input iterable is exhausted:

>>> flattened_data = ['roses', 'red', 'violets', 'blue', 'sugar', 'sweet']
>>> unflattened = list(batched(flattened_data, 2))
>>> unflattened
[('roses', 'red'), ('violets', 'blue'), ('sugar', 'sweet')]

대략 다음과 동등합니다:

def batched(iterable, n, *, strict=False):
    # batched('ABCDEFG', 3) → ABC DEF G
    if n < 1:
        raise ValueError('n must be at least one')
    iterator = iter(iterable)
    while batch := tuple(islice(iterator, n)):
        if strict and len(batch) != n:
            raise ValueError('batched(): incomplete batch')
        yield batch

Added in version 3.12.

버전 3.13에서 변경: Added the strict option.

itertools.chain(*iterables)

Make an iterator that returns elements from the first iterable until it is exhausted, then proceeds to the next iterable, until all of the iterables are exhausted. This combines multiple data sources into a single iterator. Roughly equivalent to:

def chain(*iterables):
    # chain('ABC', 'DEF') → A B C D E F
    for iterable in iterables:
        yield from iterable

classmethod chain.from_iterable(iterable)

chain()의 대체 생성자. 게으르게 평가되는 단일 이터러블 인자에서 연쇄 입력을 가져옵니다. 대략 다음과 동등합니다:

def from_iterable(iterables):
    # chain.from_iterable(['ABC', 'DEF']) → A B C D E F
    for iterable in iterables:
        yield from iterable

itertools.combinations(iterable, r)

입력 iterable에서 요소의 길이 r 서브 시퀀스들을 반환합니다.

The output is a subsequence of product() keeping only entries that are subsequences of the iterable. The length of the output is given by math.comb() which computes n! / r! / (n - r)! when 0 ≤ r ≤ n or zero when r > n.

The combination tuples are emitted in lexicographic order according to the order of the input iterable. If the input iterable is sorted, the output tuples will be produced in sorted order.

Elements are treated as unique based on their position, not on their value. If the input elements are unique, there will be no repeated values within each combination.

대략 다음과 동등합니다:

def combinations(iterable, r):
    # combinations('ABCD', 2) → AB AC AD BC BD CD
    # combinations(range(4), 3) → 012 013 023 123

    pool = tuple(iterable)
    n = len(pool)
    if r > n:
        return
    indices = list(range(r))

    yield tuple(pool[i] for i in indices)
    while True:
        for i in reversed(range(r)):
            if indices[i] != i + n - r:
                break
        else:
            return
        indices[i] += 1
        for j in range(i+1, r):
            indices[j] = indices[j-1] + 1
        yield tuple(pool[i] for i in indices)

itertools.combinations_with_replacement(iterable, r)

입력 iterable에서 요소의 길이 r 서브 시퀀스들을 반환하는데, 개별 요소를 두 번 이상 반복할 수 있습니다.

The output is a subsequence of product() that keeps only entries that are subsequences (with possible repeated elements) of the iterable. The number of subsequence returned is (n + r - 1)! / r! / (n - 1)! when n > 0.

The combination tuples are emitted in lexicographic order according to the order of the input iterable. if the input iterable is sorted, the output tuples will be produced in sorted order.

Elements are treated as unique based on their position, not on their value. If the input elements are unique, the generated combinations will also be unique.

대략 다음과 동등합니다:

def combinations_with_replacement(iterable, r):
    # combinations_with_replacement('ABC', 2) → AA AB AC BB BC CC

    pool = tuple(iterable)
    n = len(pool)
    if not n and r:
        return
    indices = [0] * r

    yield tuple(pool[i] for i in indices)
    while True:
        for i in reversed(range(r)):
            if indices[i] != n - 1:
                break
        else:
            return
        indices[i:] = [indices[i] + 1] * (r - i)
        yield tuple(pool[i] for i in indices)

Added in version 3.1.

itertools.compress(data, selectors)

Make an iterator that returns elements from data where the corresponding element in selectors is true. Stops when either the data or selectors iterables have been exhausted. Roughly equivalent to:

def compress(data, selectors):
    # compress('ABCDEF', [1,0,1,0,1,1]) → A C E F
    return (datum for datum, selector in zip(data, selectors) if selector)

Added in version 3.1.

itertools.count(start=0, step=1)

Make an iterator that returns evenly spaced values beginning with start. Can be used with map() to generate consecutive data points or with zip() to add sequence numbers. Roughly equivalent to:

def count(start=0, step=1):
    # count(10) → 10 11 12 13 14 ...
    # count(2.5, 0.5) → 2.5 3.0 3.5 ...
    n = start
    while True:
        yield n
        n += step

When counting with floating-point numbers, better accuracy can sometimes be achieved by substituting multiplicative code such as: (start + step * i for i in count()).

버전 3.1에서 변경: step 인자를 추가하고 정수가 아닌 인자를 허용했습니다.

itertools.cycle(iterable)

Make an iterator returning elements from the iterable and saving a copy of each. When the iterable is exhausted, return elements from the saved copy. Repeats indefinitely. Roughly equivalent to:

def cycle(iterable):
    # cycle('ABCD') → A B C D A B C D A B C D ...

    saved = []
    for element in iterable:
        yield element
        saved.append(element)

    while saved:
        for element in saved:
            yield element

This itertool may require significant auxiliary storage (depending on the length of the iterable).

itertools.dropwhile(predicate, iterable)

Make an iterator that drops elements from the iterable while the predicate is true and afterwards returns every element. Roughly equivalent to:

def dropwhile(predicate, iterable):
    # dropwhile(lambda x: x<5, [1,4,6,3,8]) → 6 3 8

    iterator = iter(iterable)
    for x in iterator:
        if not predicate(x):
            yield x
            break

    for x in iterator:
        yield x

Note this does not produce any output until the predicate first becomes false, so this itertool may have a lengthy start-up time.

itertools.filterfalse(predicate, iterable)

Make an iterator that filters elements from the iterable returning only those for which the predicate returns a false value. If predicate is None, returns the items that are false. Roughly equivalent to:

def filterfalse(predicate, iterable):
    # filterfalse(lambda x: x<5, [1,4,6,3,8]) → 6 8

    if predicate is None:
        predicate = bool

    for x in iterable:
        if not predicate(x):
            yield x

itertools.groupby(iterable, key=None)

iterable에서 연속적인 키와 그룹을 반환하는 이터레이터를 만듭니다. key는 각 요소의 키값을 계산하는 함수입니다. 지정되지 않거나 None이면, key의 기본값은 항등함수(identity function)이고 요소를 변경하지 않고 반환합니다. 일반적으로, iterable은 같은 키 함수로 이미 정렬되어 있어야 합니다.

groupby()의 작동은 유닉스의 uniq 필터와 유사합니다. 키 함수의 값이 변경될 때마다 중단(break)이나 새 그룹을 생성합니다 (이것이 일반적으로 같은 키 함수를 사용하여 데이터를 정렬해야 하는 이유입니다). 이 동작은 입력 순서와 관계없이 공통 요소를 집계하는 SQL의 GROUP BY와 다릅니다.

반환되는 그룹 자체는 groupby()와 하부 이터러블(iterable)을 공유하는 이터레이터입니다. 소스가 공유되므로, groupby() 객체가 진행하면, 이전 그룹은 이 더는 보이지 않게 됩니다. 따라서, 나중에 데이터가 필요하면, 리스트로 저장해야 합니다:

groups = []
uniquekeys = []
data = sorted(data, key=keyfunc)
for k, g in groupby(data, keyfunc):
    groups.append(list(g))      # Store group iterator as a list
    uniquekeys.append(k)

groupby()는 대략 다음과 동등합니다:

def groupby(iterable, key=None):
    # [k for k, g in groupby('AAAABBBCCDAABBB')] → A B C D A B
    # [list(g) for k, g in groupby('AAAABBBCCD')] → AAAA BBB CC D

    keyfunc = (lambda x: x) if key is None else key
    iterator = iter(iterable)
    exhausted = False

    def _grouper(target_key):
        nonlocal curr_value, curr_key, exhausted
        yield curr_value
        for curr_value in iterator:
            curr_key = keyfunc(curr_value)
            if curr_key != target_key:
                return
            yield curr_value
        exhausted = True

    try:
        curr_value = next(iterator)
    except StopIteration:
        return
    curr_key = keyfunc(curr_value)

    while not exhausted:
        target_key = curr_key
        curr_group = _grouper(target_key)
        yield curr_key, curr_group
        if curr_key == target_key:
            for _ in curr_group:
                pass

itertools.islice(iterable, stop)

itertools.islice(iterable, start, stop[, step])

Make an iterator that returns selected elements from the iterable. Works like sequence slicing but does not support negative values for start, stop, or step.

If start is zero or None, iteration starts at zero. Otherwise, elements from the iterable are skipped until start is reached.

If stop is None, iteration continues until the input is exhausted, if at all. Otherwise, it stops at the specified position.

If step is None, the step defaults to one. Elements are returned consecutively unless step is set higher than one which results in items being skipped.

대략 다음과 동등합니다:

def islice(iterable, *args):
    # islice('ABCDEFG', 2) → A B
    # islice('ABCDEFG', 2, 4) → C D
    # islice('ABCDEFG', 2, None) → C D E F G
    # islice('ABCDEFG', 0, None, 2) → A C E G

    s = slice(*args)
    start = 0 if s.start is None else s.start
    stop = s.stop
    step = 1 if s.step is None else s.step
    if start < 0 or (stop is not None and stop < 0) or step <= 0:
        raise ValueError

    indices = count() if stop is None else range(max(start, stop))
    next_i = start
    for i, element in zip(indices, iterable):
        if i == next_i:
            yield element
            next_i += step

If the input is an iterator, then fully consuming the islice advances the input iterator by max(start, stop) steps regardless of the step value.

itertools.pairwise(iterable)

Return successive overlapping pairs taken from the input iterable.

The number of 2-tuples in the output iterator will be one fewer than the number of inputs. It will be empty if the input iterable has fewer than two values.

대략 다음과 동등합니다:

def pairwise(iterable):
    # pairwise('ABCDEFG') → AB BC CD DE EF FG

    iterator = iter(iterable)
    a = next(iterator, None)

    for b in iterator:
        yield a, b
        a = b

Added in version 3.10.

itertools.permutations(iterable, r=None)

Return successive r length permutations of elements [https://www.britannica.com/science/permutation] from the iterable.

r이 지정되지 않았거나 None이면, r의 기본값은 iterable의 길이이며 가능한 모든 최대 길이 순열이 생성됩니다.

The output is a subsequence of product() where entries with repeated elements have been filtered out. The length of the output is given by math.perm() which computes n! / (n - r)! when 0 ≤ r ≤ n or zero when r > n.

The permutation tuples are emitted in lexicographic order according to the order of the input iterable. If the input iterable is sorted, the output tuples will be produced in sorted order.

Elements are treated as unique based on their position, not on their value. If the input elements are unique, there will be no repeated values within a permutation.

대략 다음과 동등합니다:

def permutations(iterable, r=None):
    # permutations('ABCD', 2) → AB AC AD BA BC BD CA CB CD DA DB DC
    # permutations(range(3)) → 012 021 102 120 201 210

    pool = tuple(iterable)
    n = len(pool)
    r = n if r is None else r
    if r > n:
        return

    indices = list(range(n))
    cycles = list(range(n, n-r, -1))
    yield tuple(pool[i] for i in indices[:r])

    while n:
        for i in reversed(range(r)):
            cycles[i] -= 1
            if cycles[i] == 0:
                indices[i:] = indices[i+1:] + indices[i:i+1]
                cycles[i] = n - i
            else:
                j = cycles[i]
                indices[i], indices[-j] = indices[-j], indices[i]
                yield tuple(pool[i] for i in indices[:r])
                break
        else:
            return

itertools.product(*iterables, repeat=1)

Cartesian product [https://en.wikipedia.org/wiki/Cartesian_product] of the input iterables.

대략 제너레이터 표현식에서의 중첩된 for-루프와 동등합니다. 예를 들어, product(A, B)는 ((x,y) for x in A for y in B)와 같은 것을 반환합니다.

중첩된 루프는 매 이터레이션마다 가장 오른쪽 요소가 진행되는 주행 거리계처럼 순환합니다. 이 패턴은 사전식 순서를 만들어서 입력의 이터러블들이 정렬되어 있다면, 곱(product) 튜플이 정렬된 순서로 방출됩니다.

이터러블의 자신과의 곱을 계산하려면, 선택적 repeat 키워드 인자를 사용하여 반복 횟수를 지정하십시오. 예를 들어, product(A, repeat=4)는 product(A, A, A, A)와 같은 것을 뜻합니다.

이 함수는 실제 구현이 메모리에 중간 결과를 쌓지 않는다는 점을 제외하고 다음 코드와 대략 동등합니다:

def product(*iterables, repeat=1):
    # product('ABCD', 'xy') → Ax Ay Bx By Cx Cy Dx Dy
    # product(range(2), repeat=3) → 000 001 010 011 100 101 110 111

    if repeat < 0:
        raise ValueError('repeat argument cannot be negative')
    pools = [tuple(pool) for pool in iterables] * repeat

    result = [[]]
    for pool in pools:
        result = [x+[y] for x in result for y in pool]

    for prod in result:
        yield tuple(prod)

product()가 실행되기 전에, 입력 이터러블을 완전히 소비하여, 곱을 생성하기 위해 값의 풀(pool)을 메모리에 유지합니다. 따라서, 유한 입력에만 유용합니다.

itertools.repeat(object[, times])

Make an iterator that returns object over and over again. Runs indefinitely unless the times argument is specified.

대략 다음과 동등합니다:

def repeat(object, times=None):
    # repeat(10, 3) → 10 10 10
    if times is None:
        while True:
            yield object
    else:
        for i in range(times):
            yield object

A common use for repeat is to supply a stream of constant values to map or zip:

>>> list(map(pow, range(10), repeat(2)))
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

itertools.starmap(function, iterable)

Make an iterator that computes the function using arguments obtained from the iterable. Used instead of map() when argument parameters have already been “pre-zipped” into tuples.

The difference between map() and starmap() parallels the distinction between function(a,b) and function(*c). Roughly equivalent to:

def starmap(function, iterable):
    # starmap(pow, [(2,5), (3,2), (10,3)]) → 32 9 1000
    for args in iterable:
        yield function(*args)

itertools.takewhile(predicate, iterable)

Make an iterator that returns elements from the iterable as long as the predicate is true. Roughly equivalent to:

def takewhile(predicate, iterable):
    # takewhile(lambda x: x<5, [1,4,6,3,8]) → 1 4
    for x in iterable:
        if not predicate(x):
            break
        yield x

Note, the element that first fails the predicate condition is consumed from the input iterator and there is no way to access it. This could be an issue if an application wants to further consume the input iterator after takewhile has been run to exhaustion. To work around this problem, consider using more-iterools before_and_after() [https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.before_and_after] instead.

itertools.tee(iterable, n=2)

단일 iterable에서 n 개의 독립 이터레이터를 반환합니다.

대략 다음과 동등합니다:

def tee(iterable, n=2):
    if n < 0:
        raise ValueError
    if n == 0:
        return ()
    iterator = _tee(iterable)
    result = [iterator]
    for _ in range(n - 1):
        result.append(_tee(iterator))
    return tuple(result)

class _tee:

    def __init__(self, iterable):
        it = iter(iterable)
        if isinstance(it, _tee):
            self.iterator = it.iterator
            self.link = it.link
        else:
            self.iterator = it
            self.link = [None, None]

    def __iter__(self):
        return self

    def __next__(self):
        link = self.link
        if link[1] is None:
            link[0] = next(self.iterator)
            link[1] = [None, None]
        value, self.link = link
        return value

When the input iterable is already a tee iterator object, all members of the return tuple are constructed as if they had been produced by the upstream tee() call. This “flattening step” allows nested tee() calls to share the same underlying data chain and to have a single update step rather than a chain of calls.

The flattening property makes tee iterators efficiently peekable:

def lookahead(tee_iterator):
     "Return the next value without moving the input forward"
     [forked_iterator] = tee(tee_iterator, 1)
     return next(forked_iterator)

>>> iterator = iter('abcdef')
>>> [iterator] = tee(iterator, 1)   # Make the input peekable
>>> next(iterator)                  # Move the iterator forward
'a'
>>> lookahead(iterator)             # Check next value
'b'
>>> next(iterator)                  # Continue moving forward
'b'

tee iterators are not threadsafe. A RuntimeError may be raised when simultaneously using iterators returned by the same tee() call, even if the original iterable is threadsafe.

이 이터레이터 도구에는 상당한 보조 기억 장치가 필요할 수 있습니다 (일시적으로 저장해야 하는 데이터양에 따라 다릅니다). 일반적으로, 다른 이터레이터가 시작하기 전에 하나의 이터레이터가 대부분이나 모든 데이터를 사용하면, tee() 대신 list()를 사용하는 것이 더 빠릅니다.

itertools.zip_longest(*iterables, fillvalue=None)

Make an iterator that aggregates elements from each of the iterables.

If the iterables are of uneven length, missing values are filled-in with fillvalue. If not specified, fillvalue defaults to None.

Iteration continues until the longest iterable is exhausted.

대략 다음과 동등합니다:

def zip_longest(*iterables, fillvalue=None):
    # zip_longest('ABCD', 'xy', fillvalue='-') → Ax By C- D-

    iterators = list(map(iter, iterables))
    num_active = len(iterators)
    if not num_active:
        return

    while True:
        values = []
        for i, iterator in enumerate(iterators):
            try:
                value = next(iterator)
            except StopIteration:
                num_active -= 1
                if not num_active:
                    return
                iterators[i] = repeat(fillvalue)
                value = fillvalue
            values.append(value)
        yield tuple(values)

If one of the iterables is potentially infinite, then the zip_longest() function should be wrapped with something that limits the number of calls (for example islice() or takewhile()).

Itertools 조리법

이 섹션에서는 기존 itertools를 빌딩 블록으로 사용하여 확장 도구 집합을 만드는 방법을 보여줍니다.

The primary purpose of the itertools recipes is educational. The recipes show various ways of thinking about individual tools — for example, that chain.from_iterable is related to the concept of flattening. The recipes also give ideas about ways that the tools can be combined — for example, how starmap() and repeat() can work together. The recipes also show patterns for using itertools with the operator and collections modules as well as with the built-in itertools such as map(), filter(), reversed(), and enumerate().

A secondary purpose of the recipes is to serve as an incubator. The accumulate(), compress(), and pairwise() itertools started out as recipes. Currently, the sliding_window(), iter_index(), and sieve() recipes are being tested to see whether they prove their worth.

Substantially all of these recipes and many, many others can be installed from the more-itertools [https://pypi.org/project/more-itertools/] project found on the Python Package Index:

python -m pip install more-itertools

Many of the recipes offer the same high performance as the underlying toolset. Superior memory performance is kept by processing elements one at a time rather than bringing the whole iterable into memory all at once. Code volume is kept small by linking the tools together in a functional style [https://www.cs.kent.ac.uk/people/staff/dat/miranda/whyfp90.pdf]. High speed is retained by preferring “vectorized” building blocks over the use of for-loops and generators which incur interpreter overhead.

import collections
import contextlib
import functools
import math
import operator
import random

def take(n, iterable):
    "Return first n items of the iterable as a list."
    return list(islice(iterable, n))

def prepend(value, iterable):
    "Prepend a single value in front of an iterable."
    # prepend(1, [2, 3, 4]) → 1 2 3 4
    return chain([value], iterable)

def tabulate(function, start=0):
    "Return function(0), function(1), ..."
    return map(function, count(start))

def repeatfunc(func, times=None, *args):
    "Repeat calls to func with specified arguments."
    if times is None:
        return starmap(func, repeat(args))
    return starmap(func, repeat(args, times))

def flatten(list_of_lists):
    "Flatten one level of nesting."
    return chain.from_iterable(list_of_lists)

def ncycles(iterable, n):
    "Returns the sequence elements n times."
    return chain.from_iterable(repeat(tuple(iterable), n))

def tail(n, iterable):
    "Return an iterator over the last n items."
    # tail(3, 'ABCDEFG') → E F G
    return iter(collections.deque(iterable, maxlen=n))

def consume(iterator, n=None):
    "Advance the iterator n-steps ahead. If n is None, consume entirely."
    # Use functions that consume iterators at C speed.
    if n is None:
        collections.deque(iterator, maxlen=0)
    else:
        next(islice(iterator, n, n), None)

def nth(iterable, n, default=None):
    "Returns the nth item or a default value."
    return next(islice(iterable, n, None), default)

def quantify(iterable, predicate=bool):
    "Given a predicate that returns True or False, count the True results."
    return sum(map(predicate, iterable))

def first_true(iterable, default=False, predicate=None):
    "Returns the first true value or the *default* if there is no true value."
    # first_true([a,b,c], x) → a or b or c or x
    # first_true([a,b], x, f) → a if f(a) else b if f(b) else x
    return next(filter(predicate, iterable), default)

def all_equal(iterable, key=None):
    "Returns True if all the elements are equal to each other."
    # all_equal('4٤௪౪໔', key=int) → True
    return len(take(2, groupby(iterable, key))) <= 1

def unique_justseen(iterable, key=None):
    "Yield unique elements, preserving order. Remember only the element just seen."
    # unique_justseen('AAAABBBCCDAABBB') → A B C D A B
    # unique_justseen('ABBcCAD', str.casefold) → A B c A D
    if key is None:
        return map(operator.itemgetter(0), groupby(iterable))
    return map(next, map(operator.itemgetter(1), groupby(iterable, key)))

def unique_everseen(iterable, key=None):
    "Yield unique elements, preserving order. Remember all elements ever seen."
    # unique_everseen('AAAABBBCCDAABBB') → A B C D
    # unique_everseen('ABBcCAD', str.casefold) → A B c D
    seen = set()
    if key is None:
        for element in filterfalse(seen.__contains__, iterable):
            seen.add(element)
            yield element
    else:
        for element in iterable:
            k = key(element)
            if k not in seen:
                seen.add(k)
                yield element

def unique(iterable, key=None, reverse=False):
   "Yield unique elements in sorted order. Supports unhashable inputs."
   # unique([[1, 2], [3, 4], [1, 2]]) → [1, 2] [3, 4]
   return unique_justseen(sorted(iterable, key=key, reverse=reverse), key=key)

def sliding_window(iterable, n):
    "Collect data into overlapping fixed-length chunks or blocks."
    # sliding_window('ABCDEFG', 4) → ABCD BCDE CDEF DEFG
    iterator = iter(iterable)
    window = collections.deque(islice(iterator, n - 1), maxlen=n)
    for x in iterator:
        window.append(x)
        yield tuple(window)

def grouper(iterable, n, *, incomplete='fill', fillvalue=None):
    "Collect data into non-overlapping fixed-length chunks or blocks."
    # grouper('ABCDEFG', 3, fillvalue='x') → ABC DEF Gxx
    # grouper('ABCDEFG', 3, incomplete='strict') → ABC DEF ValueError
    # grouper('ABCDEFG', 3, incomplete='ignore') → ABC DEF
    iterators = [iter(iterable)] * n
    match incomplete:
        case 'fill':
            return zip_longest(*iterators, fillvalue=fillvalue)
        case 'strict':
            return zip(*iterators, strict=True)
        case 'ignore':
            return zip(*iterators)
        case _:
            raise ValueError('Expected fill, strict, or ignore')

def roundrobin(*iterables):
    "Visit input iterables in a cycle until each is exhausted."
    # roundrobin('ABC', 'D', 'EF') → A D E B F C
    # Algorithm credited to George Sakkis
    iterators = map(iter, iterables)
    for num_active in range(len(iterables), 0, -1):
        iterators = cycle(islice(iterators, num_active))
        yield from map(next, iterators)

def subslices(seq):
    "Return all contiguous non-empty subslices of a sequence."
    # subslices('ABCD') → A AB ABC ABCD B BC BCD C CD D
    slices = starmap(slice, combinations(range(len(seq) + 1), 2))
    return map(operator.getitem, repeat(seq), slices)

def iter_index(iterable, value, start=0, stop=None):
    "Return indices where a value occurs in a sequence or iterable."
    # iter_index('AABCADEAF', 'A') → 0 1 4 7
    seq_index = getattr(iterable, 'index', None)
    if seq_index is None:
        iterator = islice(iterable, start, stop)
        for i, element in enumerate(iterator, start):
            if element is value or element == value:
                yield i
    else:
        stop = len(iterable) if stop is None else stop
        i = start
        with contextlib.suppress(ValueError):
            while True:
                yield (i := seq_index(value, i, stop))
                i += 1

def iter_except(func, exception, first=None):
    "Convert a call-until-exception interface to an iterator interface."
    # iter_except(d.popitem, KeyError) → non-blocking dictionary iterator
    with contextlib.suppress(exception):
        if first is not None:
            yield first()
        while True:
            yield func()

The following recipes have a more mathematical flavor:

def powerset(iterable):
    "powerset([1,2,3]) → () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
    s = list(iterable)
    return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))

def sum_of_squares(iterable):
    "Add up the squares of the input values."
    # sum_of_squares([10, 20, 30]) → 1400
    return math.sumprod(*tee(iterable))

def reshape(matrix, cols):
    "Reshape a 2-D matrix to have a given number of columns."
    # reshape([(0, 1), (2, 3), (4, 5)], 3) →  (0, 1, 2), (3, 4, 5)
    return batched(chain.from_iterable(matrix), cols, strict=True)

def transpose(matrix):
    "Swap the rows and columns of a 2-D matrix."
    # transpose([(1, 2, 3), (11, 22, 33)]) → (1, 11) (2, 22) (3, 33)
    return zip(*matrix, strict=True)

def matmul(m1, m2):
    "Multiply two matrices."
    # matmul([(7, 5), (3, 5)], [(2, 5), (7, 9)]) → (49, 80), (41, 60)
    n = len(m2[0])
    return batched(starmap(math.sumprod, product(m1, transpose(m2))), n)

def convolve(signal, kernel):
    """Discrete linear convolution of two iterables.
    Equivalent to polynomial multiplication.

    Convolutions are mathematically commutative; however, the inputs are
    evaluated differently.  The signal is consumed lazily and can be
    infinite. The kernel is fully consumed before the calculations begin.

    Article:  https://betterexplained.com/articles/intuitive-convolution/
    Video:    https://www.youtube.com/watch?v=KuXjwB4LzSA
    """
    # convolve([1, -1, -20], [1, -3]) → 1 -4 -17 60
    # convolve(data, [0.25, 0.25, 0.25, 0.25]) → Moving average (blur)
    # convolve(data, [1/2, 0, -1/2]) → 1st derivative estimate
    # convolve(data, [1, -2, 1]) → 2nd derivative estimate
    kernel = tuple(kernel)[::-1]
    n = len(kernel)
    padded_signal = chain(repeat(0, n-1), signal, repeat(0, n-1))
    windowed_signal = sliding_window(padded_signal, n)
    return map(math.sumprod, repeat(kernel), windowed_signal)

def polynomial_from_roots(roots):
    """Compute a polynomial's coefficients from its roots.

       (x - 5) (x + 4) (x - 3)  expands to:   x³ -4x² -17x + 60
    """
    # polynomial_from_roots([5, -4, 3]) → [1, -4, -17, 60]
    factors = zip(repeat(1), map(operator.neg, roots))
    return list(functools.reduce(convolve, factors, [1]))

def polynomial_eval(coefficients, x):
    """Evaluate a polynomial at a specific value.

    Computes with better numeric stability than Horner's method.
    """
    # Evaluate x³ -4x² -17x + 60 at x = 5
    # polynomial_eval([1, -4, -17, 60], x=5) → 0
    n = len(coefficients)
    if not n:
        return type(x)(0)
    powers = map(pow, repeat(x), reversed(range(n)))
    return math.sumprod(coefficients, powers)

def polynomial_derivative(coefficients):
    """Compute the first derivative of a polynomial.

       f(x)  =  x³ -4x² -17x + 60
       f'(x) = 3x² -8x  -17
    """
    # polynomial_derivative([1, -4, -17, 60]) → [3, -8, -17]
    n = len(coefficients)
    powers = reversed(range(1, n))
    return list(map(operator.mul, coefficients, powers))

def sieve(n):
    "Primes less than n."
    # sieve(30) → 2 3 5 7 11 13 17 19 23 29
    if n > 2:
        yield 2
    data = bytearray((0, 1)) * (n // 2)
    for p in iter_index(data, 1, start=3, stop=math.isqrt(n) + 1):
        data[p*p : n : p+p] = bytes(len(range(p*p, n, p+p)))
    yield from iter_index(data, 1, start=3)

def factor(n):
    "Prime factors of n."
    # factor(99) → 3 3 11
    # factor(1_000_000_000_000_007) → 47 59 360620266859
    # factor(1_000_000_000_000_403) → 1000000000000403
    for prime in sieve(math.isqrt(n) + 1):
        while not n % prime:
            yield prime
            n //= prime
            if n == 1:
                return
    if n > 1:
        yield n

def totient(n):
    "Count of natural numbers up to n that are coprime to n."
    # https://mathworld.wolfram.com/TotientFunction.html
    # totient(12) → 4 because len([1, 5, 7, 11]) == 4
    for prime in set(factor(n)):
        n -= n // prime
    return n

functools — Higher-order functions and operations on callable objects

소스 코드: Lib/functools.py [https://github.com/python/cpython/tree/main/Lib/functools.py]

functools 모듈은 고차 함수를 위한 것입니다: 다른 함수에 작용하거나 다른 함수를 반환하는 함수. 일반적으로, 모든 콜러블 객체는 이 모듈의 목적상 함수로 취급될 수 있습니다.

functools 모듈은 다음 함수를 정의합니다:

@functools.cache(user_function)

단순하고 가벼운 무제한 함수 캐시. 때때로 “memoize” [https://en.wikipedia.org/wiki/Memoization]라고도 합니다.

Returns the same as lru_cache(maxsize=None), creating a thin wrapper around a dictionary lookup for the function arguments. Because it never needs to evict old values, this is smaller and faster than lru_cache() with a size limit.

예를 들면:

@cache
def factorial(n):
    return n * factorial(n-1) if n else 1

>>> factorial(10)      # no previously cached result, makes 11 recursive calls
3628800
>>> factorial(5)       # just looks up cached value result
120
>>> factorial(12)      # makes two new recursive calls, the other 10 are cached
479001600

The cache is threadsafe so that the wrapped function can be used in multiple threads. This means that the underlying data structure will remain coherent during concurrent updates.

It is possible for the wrapped function to be called more than once if another thread makes an additional call before the initial call has been completed and cached.

Added in version 3.9.

@functools.cached_property(func)

클래스의 메서드를 값이 한 번 계산된 다음 인스턴스 수명 동안 일반 어트리뷰트로 캐시 되는 프로퍼티로 변환합니다. property()와 유사하고, 캐싱이 추가되었습니다. 비싸게 계산되고 그 외에는 사실상 불변인 인스턴스의 프로퍼티에 유용합니다.

예:

class DataSet:

    def __init__(self, sequence_of_numbers):
        self._data = tuple(sequence_of_numbers)

    @cached_property
    def stdev(self):
        return statistics.stdev(self._data)

cached_property()의 메커니즘은 property()와 다소 다릅니다. 일반 프로퍼티는 setter가 정의되지 않은 경우 어트리뷰트 쓰기를 차단합니다. 이와는 달리, cached_property는 쓰기를 허용합니다.

cached_property 데코레이터는 조회 시에만, 같은 이름의 어트리뷰트가 존재하지 않을 때만 실행됩니다. 실행되면, cached_property는 같은 이름의 어트리뷰트에 기록합니다. 후속 어트리뷰트 읽기와 쓰기는 cached_property 메서드보다 우선하며 일반 어트리뷰트처럼 작동합니다.

캐시 된 값은 어트리뷰트를 삭제하여 지울 수 있습니다. 이렇게 하면 cached_property 메서드가 다시 실행됩니다.

The cached_property does not prevent a possible race condition in multi-threaded usage. The getter function could run more than once on the same instance, with the latest run setting the cached value. If the cached property is idempotent or otherwise not harmful to run more than once on an instance, this is fine. If synchronization is needed, implement the necessary locking inside the decorated getter function or around the cached property access.

이 데코레이터는 PEP 412 [https://peps.python.org/pep-0412/] 키 공유 딕셔너리의 작동을 방해함에 유의하십시오. 이는 인스턴스 딕셔너리가 평소보다 더 많은 공간을 차지할 수 있음을 의미합니다.

또한, 이 데코레이터는 각 인스턴스의 __dict__ 어트리뷰트가 가변 매핑일 것을 요구합니다. 이는 메타 클래스(형 인스턴스의 __dict__ 어트리뷰트가 클래스 이름 공간에 대한 읽기 전용 프락시이기 때문에)와 __dict__를 정의된 슬롯 중 하나로 포함하지 않고 __slots__를 지정하는 것(이러한 클래스는 __dict__ 어트리뷰트를 전혀 제공하지 않기 때문에)과 같은 일부 형에서 작동하지 않음을 의미합니다.

If a mutable mapping is not available or if space-efficient key sharing is desired, an effect similar to cached_property() can also be achieved by stacking property() on top of lru_cache(). See How do I cache method calls? for more details on how this differs from cached_property().

Added in version 3.8.

버전 3.12에서 변경: Prior to Python 3.12, cached_property included an undocumented lock to ensure that in multi-threaded usage the getter function was guaranteed to run only once per instance. However, the lock was per-property, not per-instance, which could result in unacceptably high lock contention. In Python 3.12+ this locking is removed.

functools.cmp_to_key(func)

구식 비교 함수를 키 함수로 변환합니다. (sorted(), min(), max(), heapq.nlargest(), heapq.nsmallest(), itertools.groupby()와 같은) 키 함수를 받아들이는 도구와 함께 사용됩니다. 이 함수는 주로 비교 함수 사용을 지원하는 파이썬 2에서 변환되는 프로그램의 전이 도구로 사용됩니다.

A comparison function is any callable that accepts two arguments, compares them, and returns a negative number for less-than, zero for equality, or a positive number for greater-than. A key function is a callable that accepts one argument and returns another value to be used as the sort key.

예:

sorted(iterable, key=cmp_to_key(locale.strcoll))  # locale-aware sort order

정렬 예제와 간략한 정렬 자습서는 Sorting Techniques를 참조하십시오.

Added in version 3.2.

@functools.lru_cache(user_function)

@functools.lru_cache(maxsize=128, typed=False)

가장 최근의 maxsize 호출까지 저장하는 기억하는(memoizing) 콜러블 함수를 감싸는 데코레이터. 비싸거나 I/O 병목 함수가 같은 인자로 주기적으로 호출될 때 시간을 절약할 수 있습니다.

The cache is threadsafe so that the wrapped function can be used in multiple threads. This means that the underlying data structure will remain coherent during concurrent updates.

It is possible for the wrapped function to be called more than once if another thread makes an additional call before the initial call has been completed and cached.

Since a dictionary is used to cache results, the positional and keyword arguments to the function must be hashable.

Distinct argument patterns may be considered to be distinct calls with separate cache entries. For example, f(a=1, b=2) and f(b=2, a=1) differ in their keyword argument order and may have two separate cache entries.

user_function이 지정되면, 콜러블이어야 합니다. 이는 lru_cache 데코레이터를 사용자 함수에 직접 적용 할 수 있도록 하며, maxsize를 기본값 128로 유지합니다:

@lru_cache
def count_vowels(sentence):
    return sum(sentence.count(vowel) for vowel in 'AEIOUaeiou')

maxsize가 None으로 설정되면, LRU 기능이 비활성화되고 캐시가 제한 없이 커질 수 있습니다.

If typed is set to true, function arguments of different types will be cached separately. If typed is false, the implementation will usually regard them as equivalent calls and only cache a single result. (Some types such as str and int may be cached separately even when typed is false.)

Note, type specificity applies only to the function’s immediate arguments rather than their contents. The scalar arguments, Decimal(42) and Fraction(42) are be treated as distinct calls with distinct results. In contrast, the tuple arguments ('answer', Decimal(42)) and ('answer', Fraction(42)) are treated as equivalent.

The wrapped function is instrumented with a cache_parameters() function that returns a new dict showing the values for maxsize and typed. This is for information purposes only. Mutating the values has no effect.

To help measure the effectiveness of the cache and tune the maxsize parameter, the wrapped function is instrumented with a cache_info() function that returns a named tuple showing hits, misses, maxsize and currsize.

데코레이터는 캐시를 지우거나 무효로 하기 위한 cache_clear() 함수도 제공합니다.

원래의 하부 함수는 __wrapped__ 어트리뷰트를 통해 액세스 할 수 있습니다. 이것은 인트로스펙션, 캐시 우회 또는 다른 캐시로 함수를 다시 래핑하는 데 유용합니다.

The cache keeps references to the arguments and return values until they age out of the cache or until the cache is cleared.

If a method is cached, the self instance argument is included in the cache. See How do I cache method calls?

An LRU (least recently used) cache [https://en.wikipedia.org/wiki/Cache_replacement_policies#Least_Recently_Used_(LRU)] works best when the most recent calls are the best predictors of upcoming calls (for example, the most popular articles on a news server tend to change each day). The cache’s size limit assures that the cache does not grow without bound on long-running processes such as web servers.

In general, the LRU cache should only be used when you want to reuse previously computed values. Accordingly, it doesn’t make sense to cache functions with side-effects, functions that need to create distinct mutable objects on each call (such as generators and async functions), or impure functions such as time() or random().

정적 웹 콘텐츠를 위한 LRU 캐시의 예:

@lru_cache(maxsize=32)
def get_pep(num):
    'Retrieve text of a Python Enhancement Proposal'
    resource = f'https://peps.python.org/pep-{num:04d}'
    try:
        with urllib.request.urlopen(resource) as s:
            return s.read()
    except urllib.error.HTTPError:
        return 'Not Found'

>>> for n in 8, 290, 308, 320, 8, 218, 320, 279, 289, 320, 9991:
...     pep = get_pep(n)
...     print(n, len(pep))

>>> get_pep.cache_info()
CacheInfo(hits=3, misses=8, maxsize=32, currsize=8)

동적 프로그래밍(dynamic programming) [https://en.wikipedia.org/wiki/Dynamic_programming] 기법을 구현하기 위해 캐시를 사용하여 피보나치 수 [https://en.wikipedia.org/wiki/Fibonacci_number]를 효율적으로 계산하는 예:

@lru_cache(maxsize=None)
def fib(n):
    if n < 2:
        return n
    return fib(n-1) + fib(n-2)

>>> [fib(n) for n in range(16)]
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]

>>> fib.cache_info()
CacheInfo(hits=28, misses=16, maxsize=None, currsize=16)

Added in version 3.2.

버전 3.3에서 변경: typed 옵션을 추가했습니다.

버전 3.8에서 변경: user_function 옵션을 추가했습니다.

버전 3.9에서 변경: Added the function cache_parameters()

@functools.total_ordering

하나 이상의 풍부한 비교(rich comparison) 순서 메서드를 정의하는 클래스를 주면, 이 클래스 데코레이터가 나머지를 제공합니다. 가능한 모든 풍부한 비교 연산을 지정하는 데 드는 노력이 단순화됩니다:

클래스는 __lt__(), __le__(), __gt__() 또는 __ge__() 중 하나를 정의해야 합니다. 또한, 클래스는 __eq__() 메서드를 제공해야 합니다.

예를 들면:

@total_ordering
class Student:
    def _is_valid_operand(self, other):
        return (hasattr(other, "lastname") and
                hasattr(other, "firstname"))
    def __eq__(self, other):
        if not self._is_valid_operand(other):
            return NotImplemented
        return ((self.lastname.lower(), self.firstname.lower()) ==
                (other.lastname.lower(), other.firstname.lower()))
    def __lt__(self, other):
        if not self._is_valid_operand(other):
            return NotImplemented
        return ((self.lastname.lower(), self.firstname.lower()) <
                (other.lastname.lower(), other.firstname.lower()))

참고

이 데코레이터를 사용하면 올바르게 동작하는 전 순서(totally ordered) 형을 쉽게 만들 수 있지만, 파생된 비교 메서드에서 실행 속도가 느려지고 스택 트레이스가 더 복잡해지는 대가를 지불합니다. 성능 벤치마킹이 이것이 특정 응용 프로그램의 병목임을 가리키면, 6가지의 풍부한 비교 메서드를 모두 구현하여 속도를 쉽게 높일 수 있습니다.

참고

This decorator makes no attempt to override methods that have been declared in the class or its superclasses. Meaning that if a superclass defines a comparison operator, total_ordering will not implement it again, even if the original method is abstract.

Added in version 3.2.

버전 3.4에서 변경: Returning NotImplemented from the underlying comparison function for unrecognised types is now supported.

functools.Placeholder

A singleton object used as a sentinel to reserve a place for positional arguments when calling partial() and partialmethod().

Added in version 3.14.

functools.partial(func, /, *args, **keywords)

호출될 때 위치 인자 args와 키워드 인자 keywords로 호출된 func처럼 동작하는 새 partial 객체를 반환합니다. 더 많은 인자가 호출에 제공되면, args에 추가됩니다. 추가 키워드 인자가 제공되면, keywords를 확장하고 대체합니다. 대략 다음과 동등합니다:

def partial(func, /, *args, **keywords):
    def newfunc(*more_args, **more_keywords):
        return func(*args, *more_args, **(keywords | more_keywords))
    newfunc.func = func
    newfunc.args = args
    newfunc.keywords = keywords
    return newfunc

The partial() function is used for partial function application which “freezes” some portion of a function’s arguments and/or keywords resulting in a new object with a simplified signature. For example, partial() can be used to create a callable that behaves like the int() function where the base argument defaults to 2:

>>> basetwo = partial(int, base=2)
>>> basetwo.__doc__ = 'Convert base 2 string to an int.'
>>> basetwo('10010')
18

If Placeholder sentinels are present in args, they will be filled first when partial() is called. This makes it possible to pre-fill any positional argument with a call to partial(); without Placeholder, only the first positional argument can be pre-filled.

If any Placeholder sentinels are present, all must be filled at call time:

>>> say_to_world = partial(print, Placeholder, Placeholder, "world!")
>>> say_to_world('Hello', 'dear')
Hello dear world!

Calling say_to_world('Hello') raises a TypeError, because only one positional argument is provided, but there are two placeholders that must be filled in.

If partial() is applied to an existing partial() object, Placeholder sentinels of the input object are filled in with new positional arguments. A placeholder can be retained by inserting a new Placeholder sentinel to the place held by a previous Placeholder:

>>> from functools import partial, Placeholder as _
>>> remove = partial(str.replace, _, _, '')
>>> message = 'Hello, dear dear world!'
>>> remove(message, ' dear')
'Hello, world!'
>>> remove_dear = partial(remove, _, ' dear')
>>> remove_dear(message)
'Hello, world!'
>>> remove_first_dear = partial(remove_dear, _, 1)
>>> remove_first_dear(message)
'Hello, dear world!'

Placeholder has no special treatment when used in a keyword argument to partial().

버전 3.14에서 변경: Added support for Placeholder in positional arguments.

class functools.partialmethod(func, /, *args, **keywords)

직접 호출하기보다는 메서드 정의로 사용되도록 설계된 것을 제외하고는 partial과 같이 동작하는 새 partialmethod 디스크립터를 반환합니다.

func는 디스크립터나 콜러블이어야 합니다 (일반 함수처럼 둘 모두인 객체는 디스크립터로 처리됩니다).

func가 디스크립터(가령 일반 파이썬 함수, classmethod(), staticmethod(), abstractmethod() 또는 partialmethod의 다른 인스턴스)이면, __get__에 대한 호출은 하부 디스크립터에 위임되고, 적절한 partial 객체가 결과로 반환됩니다.

func가 디스크립터가 아닌 콜러블이면, 적절한 연결된 메서드가 동적으로 만들어집니다. 이것은 메서드로 사용될 때 일반 파이썬 함수처럼 작동합니다: partialmethod 생성자에 제공된 args와 keywords보다도 전에 self 인자가 첫 번째 위치 인자로 삽입됩니다.

예:

>>> class Cell:
...     def __init__(self):
...         self._alive = False
...     @property
...     def alive(self):
...         return self._alive
...     def set_state(self, state):
...         self._alive = bool(state)
...     set_alive = partialmethod(set_state, True)
...     set_dead = partialmethod(set_state, False)
...
>>> c = Cell()
>>> c.alive
False
>>> c.set_alive()
>>> c.alive
True

Added in version 3.4.

functools.reduce(function, iterable, /[, initial])

Apply function of two arguments cumulatively to the items of iterable, from left to right, so as to reduce the iterable to a single value. For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates ((((1+2)+3)+4)+5). The left argument, x, is the accumulated value and the right argument, y, is the update value from the iterable. If the optional initial is present, it is placed before the items of the iterable in the calculation, and serves as a default when the iterable is empty. If initial is not given and iterable contains only one item, the first item is returned.

대략 다음과 동등합니다:

initial_missing = object()

def reduce(function, iterable, /, initial=initial_missing):
    it = iter(iterable)
    if initial is initial_missing:
        value = next(it)
    else:
        value = initial
    for element in it:
        value = function(value, element)
    return value

모든 중간값을 산출하는 이터레이터는 itertools.accumulate()를 참조하십시오.

버전 3.14에서 변경: initial is now supported as a keyword argument.

@functools.singledispatch

함수를 싱글 디스패치 제네릭 함수로 변환합니다.

To define a generic function, decorate it with the @singledispatch decorator. When defining a function using @singledispatch, note that the dispatch happens on the type of the first argument:

>>> from functools import singledispatch
>>> @singledispatch
... def fun(arg, verbose=False):
...     if verbose:
...         print("Let me just say,", end=" ")
...     print(arg)

To add overloaded implementations to the function, use the register() attribute of the generic function, which can be used as a decorator. For functions annotated with types, the decorator will infer the type of the first argument automatically:

>>> @fun.register
... def _(arg: int, verbose=False):
...     if verbose:
...         print("Strength in numbers, eh?", end=" ")
...     print(arg)
...
>>> @fun.register
... def _(arg: list, verbose=False):
...     if verbose:
...         print("Enumerate this:")
...     for i, elem in enumerate(arg):
...         print(i, elem)

types.UnionType and typing.Union can also be used:

>>> @fun.register
... def _(arg: int | float, verbose=False):
...     if verbose:
...         print("Strength in numbers, eh?", end=" ")
...     print(arg)
...
>>> from typing import Union
>>> @fun.register
... def _(arg: Union[list, set], verbose=False):
...     if verbose:
...         print("Enumerate this:")
...     for i, elem in enumerate(arg):
...         print(i, elem)
...

형 어노테이션을 사용하지 않는 코드의 경우, 적절한 형 인자를 데코레이터 자체에 명시적으로 전달할 수 있습니다:

>>> @fun.register(complex)
... def _(arg, verbose=False):
...     if verbose:
...         print("Better than complicated.", end=" ")
...     print(arg.real, arg.imag)
...

For code that dispatches on a collections type (e.g., list), but wants to typehint the items of the collection (e.g., list[int]), the dispatch type should be passed explicitly to the decorator itself with the typehint going into the function definition:

>>> @fun.register(list)
... def _(arg: list[int], verbose=False):
...     if verbose:
...         print("Enumerate this:")
...     for i, elem in enumerate(arg):
...         print(i, elem)

참고

At runtime the function will dispatch on an instance of a list regardless of the type contained within the list i.e. [1,2,3] will be dispatched the same as ["foo", "bar", "baz"]. The annotation provided in this example is for static type checkers only and has no runtime impact.

To enable registering lambdas and pre-existing functions, the register() attribute can also be used in a functional form:

>>> def nothing(arg, verbose=False):
...     print("Nothing.")
...
>>> fun.register(type(None), nothing)

The register() attribute returns the undecorated function. This enables decorator stacking, pickling, and the creation of unit tests for each variant independently:

>>> @fun.register(float)
... @fun.register(Decimal)
... def fun_num(arg, verbose=False):
...     if verbose:
...         print("Half of your number:", end=" ")
...     print(arg / 2)
...
>>> fun_num is fun
False

호출되면, 제네릭 함수는 첫 번째 인자의 형에 따라 디스패치 합니다:

>>> fun("Hello, world.")
Hello, world.
>>> fun("test.", verbose=True)
Let me just say, test.
>>> fun(42, verbose=True)
Strength in numbers, eh? 42
>>> fun(['spam', 'spam', 'eggs', 'spam'], verbose=True)
Enumerate this:
0 spam
1 spam
2 eggs
3 spam
>>> fun(None)
Nothing.
>>> fun(1.23)
0.615

Where there is no registered implementation for a specific type, its method resolution order is used to find a more generic implementation. The original function decorated with @singledispatch is registered for the base object type, which means it is used if no better implementation is found.

If an implementation is registered to an abstract base class, virtual subclasses of the base class will be dispatched to that implementation:

>>> from collections.abc import Mapping
>>> @fun.register
... def _(arg: Mapping, verbose=False):
...     if verbose:
...         print("Keys & Values")
...     for key, value in arg.items():
...         print(key, "=>", value)
...
>>> fun({"a": "b"})
a => b

To check which implementation the generic function will choose for a given type, use the dispatch() attribute:

>>> fun.dispatch(float)
<function fun_num at 0x1035a2840>
>>> fun.dispatch(dict)    # note: default implementation
<function fun at 0x103fe0000>

등록된 모든 구현에 액세스하려면, 읽기 전용 registry 어트리뷰트를 사용하십시오:

>>> fun.registry.keys()
dict_keys([<class 'NoneType'>, <class 'int'>, <class 'object'>,
          <class 'decimal.Decimal'>, <class 'list'>,
          <class 'float'>])
>>> fun.registry[float]
<function fun_num at 0x1035a2840>
>>> fun.registry[object]
<function fun at 0x103fe0000>

Added in version 3.4.

버전 3.7에서 변경: The register() attribute now supports using type annotations.

버전 3.11에서 변경: The register() attribute now supports types.UnionType and typing.Union as type annotations.

class functools.singledispatchmethod(func)

메서드를 싱글 디스패치 제네릭 함수로 변환합니다.

To define a generic method, decorate it with the @singledispatchmethod decorator. When defining a function using @singledispatchmethod, note that the dispatch happens on the type of the first non-self or non-cls argument:

class Negator:
    @singledispatchmethod
    def neg(self, arg):
        raise NotImplementedError("Cannot negate a")

    @neg.register
    def _(self, arg: int):
        return -arg

    @neg.register
    def _(self, arg: bool):
        return not arg

@singledispatchmethod supports nesting with other decorators such as @classmethod. Note that to allow for dispatcher.register, singledispatchmethod must be the outer most decorator. Here is the Negator class with the neg methods bound to the class, rather than an instance of the class:

class Negator:
    @singledispatchmethod
    @classmethod
    def neg(cls, arg):
        raise NotImplementedError("Cannot negate a")

    @neg.register
    @classmethod
    def _(cls, arg: int):
        return -arg

    @neg.register
    @classmethod
    def _(cls, arg: bool):
        return not arg

The same pattern can be used for other similar decorators: @staticmethod, @abstractmethod, and others.

Added in version 3.8.

functools.update_wrapper(wrapper, wrapped, assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES)

Update a wrapper function to look like the wrapped function. The optional arguments are tuples to specify which attributes of the original function are assigned directly to the matching attributes on the wrapper function and which attributes of the wrapper function are updated with the corresponding attributes from the original function. The default values for these arguments are the module level constants WRAPPER_ASSIGNMENTS (which assigns to the wrapper function’s __module__, __name__, __qualname__, __annotations__, __type_params__, and __doc__, the documentation string) and WRAPPER_UPDATES (which updates the wrapper function’s __dict__, i.e. the instance dictionary).

내부 검사와 기타 목적(예를 들어 lru_cache()와 같은 캐싱 데코레이터 우회)을 위해 원래 함수에 액세스 할 수 있도록, 이 함수는 래핑 되는 함수를 가리키는 __wrapped__ 어트리뷰트를 wrapper에 자동으로 추가합니다.

이 함수의 주요 용도는 데코레이트 된 함수를 래핑하고 wrapper를 반환하는 데코레이터 함수에서 사용하는 것입니다. wrapper 함수가 갱신되지 않으면, 반환된 함수의 메타 데이터는 원래 함수 정의가 아닌 wrapper 정의를 반영하게 되어 일반적으로 도움이 되지 않습니다.

update_wrapper()는 함수 이외의 콜러블과 함께 사용할 수 있습니다. 래핑 되는 객체에서 누락된 assigned나 updated로 이름 지정된 어트리뷰트는 무시됩니다 (즉, 이 함수는 wrapper 함수에서 그 어트리뷰트를 설정하려고 시도하지 않습니다). wrapper 함수 자체에 updated에 이름 지정된 어트리뷰트가 없으면 여전히 AttributeError가 발생합니다.

버전 3.2에서 변경: The __wrapped__ attribute is now automatically added. The __annotations__ attribute is now copied by default. Missing attributes no longer trigger an AttributeError.

버전 3.4에서 변경: __wrapped__ 어트리뷰트는 이제 해당 함수가 __wrapped__ 어트리뷰트를 정의한 경우에도 항상 래핑 된 함수를 참조합니다. (bpo-17482 [https://bugs.python.org/issue?@action=redirect&bpo=17482]를 참조하십시오)

버전 3.12에서 변경: The __type_params__ attribute is now copied by default.

@functools.wraps(wrapped, assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES)

래퍼 함수를 정의할 때 함수 데코레이터로 update_wrapper()를 호출하기 위한 편의 함수입니다. partial(update_wrapper, wrapped=wrapped, assigned=assigned, updated=updated)와 동등합니다. 예를 들면:

>>> from functools import wraps
>>> def my_decorator(f):
...     @wraps(f)
...     def wrapper(*args, **kwds):
...         print('Calling decorated function')
...         return f(*args, **kwds)
...     return wrapper
...
>>> @my_decorator
... def example():
...     """Docstring"""
...     print('Called example function')
...
>>> example()
Calling decorated function
Called example function
>>> example.__name__
'example'
>>> example.__doc__
'Docstring'

이 데코레이터 팩토리를 사용하지 않으면, example 함수의 이름은 'wrapper'가 되고, 원래 example()의 독스트링은 잃어버리게 됩니다.

partial 객체

partial 객체는 partial()이 만든 콜러블 객체입니다. 세 가지 읽기 전용 어트리뷰트가 있습니다:

partial.func

콜러블 객체나 함수. partial 객체에 대한 호출은 새로운 인자와 키워드와 함께 func로 전달됩니다.

partial.args

partial 객체 호출에 제공되는 위치 인자 앞에 추가될 가장 왼쪽 위치 인자들입니다.

partial.keywords

partial 객체가 호출될 때 제공될 키워드 인자들입니다.

partial objects are like function objects in that they are callable, weak referenceable, and can have attributes. There are some important differences. For instance, the __name__ and __doc__ attributes are not created automatically.

operator — Standard operators as functions

소스 코드: Lib/operator.py [https://github.com/python/cpython/tree/main/Lib/operator.py]

operator 모듈은 파이썬의 내장 연산자에 해당하는 효율적인 함수 집합을 내보냅니다. 예를 들어, operator.add(x, y)는 x+y 표현식과 동등합니다. 많은 함수 이름은 특수 메서드에 사용되는 이름인데, 이중 밑줄이 없습니다. 이전 버전과의 호환성을 위해, 이들 중 많은 것은 이중 밑줄이 있는 변형을 가집니다. 이중 밑줄이 없는 변형이 명확성을 위해 선호됩니다.

함수는 객체 비교, 논리 연산, 수학 연산 및 시퀀스 연산을 수행하는 범주로 분류됩니다.

객체 비교 함수는 모든 객체에 유용하며, 이들이 지원하는 풍부한 비교(rich comparison) 연산자의 이름을 따릅니다:

operator.lt(a, b)

operator.le(a, b)

operator.eq(a, b)

operator.ne(a, b)

operator.ge(a, b)

operator.gt(a, b)

operator.__lt__(a, b)

operator.__le__(a, b)

operator.__eq__(a, b)

operator.__ne__(a, b)

operator.__ge__(a, b)

operator.__gt__(a, b)

a와 b 사이에 “풍부한 비교(rich comparisons)”를 수행합니다. 구체적으로, lt(a, b)는 a < b와 동등하고, le(a, b)는 a <= b와 동등하고, eq(a, b)는 a == b와 동등하고, ne(a, b)는 a != b와 동등하고, gt(a, b)는 a > b와 동등하고, ge(a, b)는 a >= b와 동등합니다. 이러한 함수는 불리언 값으로 해석 할 수도 있고, 그렇지 않을 수도 있는 임의의 값을 반환 할 수 있음에 유의하십시오. 풍부한 비교에 대한 자세한 정보는 비교를 참조하십시오.

논리 연산도 일반적으로 모든 객체에 적용 할 수 있으며, 진릿값 검사, 아이덴티티 검사 및 불리언 연산을 지원합니다:

operator.not_(obj)

operator.__not__(obj)

Return the outcome of not obj. (Note that there is no __not__() method for object instances; only the interpreter core defines this operation. The result is affected by the __bool__() and __len__() methods.)

operator.truth(obj)

obj가 참이면 True를 반환하고, 그렇지 않으면 False를 반환합니다. 이것은 bool 생성자를 사용하는 것과 동등합니다.

operator.is_(a, b)

a is b를 반환합니다. 객체 아이덴티티를 검사합니다.

operator.is_not(a, b)

a is not b를 반환합니다. 객체 아이덴티티를 검사합니다.

operator.is_none(a)

Return a is None. Tests object identity.

Added in version 3.14.

operator.is_not_none(a)

Return a is not None. Tests object identity.

Added in version 3.14.

수학적 및 비트별 연산이 가장 많습니다:

operator.abs(obj)

operator.__abs__(obj)

obj의 절댓값을 반환합니다.

operator.add(a, b)

operator.__add__(a, b)

a와 b 숫자에 대해, a + b를 반환합니다.

operator.and_(a, b)

operator.__and__(a, b)

a와 b의 비트별 논리곱(and)을 반환합니다.

operator.floordiv(a, b)

operator.__floordiv__(a, b)

a // b를 반환합니다.

operator.index(a)

operator.__index__(a)

정수로 변환된 a를 반환합니다. a.__index__()와 동등합니다.

버전 3.10에서 변경: The result always has exact type int. Previously, the result could have been an instance of a subclass of int.

operator.inv(obj)

operator.invert(obj)

operator.__inv__(obj)

operator.__invert__(obj)

숫자 obj의 비트별 반전을 반환합니다. 이것은 ~obj와 동등합니다.

operator.lshift(a, b)

operator.__lshift__(a, b)

a를 b만큼 왼쪽으로 시프트 한 값을 반환합니다.

operator.mod(a, b)

operator.__mod__(a, b)

a % b를 반환합니다.

operator.mul(a, b)

operator.__mul__(a, b)

a와 b 숫자에 대해, a * b를 반환합니다.

operator.matmul(a, b)

operator.__matmul__(a, b)

a @ b를 반환합니다.

Added in version 3.5.

operator.neg(obj)

operator.__neg__(obj)

obj의 부정(-obj)을 반환합니다.

operator.or_(a, b)

operator.__or__(a, b)

a와 b의 비트별 논리합(or)을 반환합니다.

operator.pos(obj)

operator.__pos__(obj)

양의 obj(+obj)를 반환합니다.

operator.pow(a, b)

operator.__pow__(a, b)

a와 b 숫자에 대해, a ** b를 반환합니다.

operator.rshift(a, b)

operator.__rshift__(a, b)

a를 b만큼 오른쪽으로 시프트 한 값을 반환합니다.

operator.sub(a, b)

operator.__sub__(a, b)

a - b를 반환합니다.

operator.truediv(a, b)

operator.__truediv__(a, b)

a / b를 반환합니다. 여기서 2/3는 0이 아니라 .66입니다. 이것은 “실수(true)” 나누기라고 도합니다.

operator.xor(a, b)

operator.__xor__(a, b)

a와 b의 비트별 배타적 논리합을 반환합니다.

시퀀스에 적용되는 연산(일부는 매핑에도 적용됩니다)은 다음과 같습니다:

operator.concat(a, b)

operator.__concat__(a, b)

a와 b 시퀀스에 대해 a + b를 반환합니다.

operator.contains(a, b)

operator.__contains__(a, b)

b in a 검사의 결과를 반환합니다. 피연산자가 뒤집혀 있음에 유의하십시오.

operator.countOf(a, b)

a에서 b가 발생하는 횟수를 반환합니다.

operator.delitem(a, b)

operator.__delitem__(a, b)

a의 값을 인덱스 b에서 제거합니다.

operator.getitem(a, b)

operator.__getitem__(a, b)

인덱스 b에 있는 a의 값을 반환합니다.

operator.indexOf(a, b)

a에서 b가 처음으로 발견되는 인덱스를 반환합니다.

operator.setitem(a, b, c)

operator.__setitem__(a, b, c)

인덱스 b의 a의 값을 c로 설정합니다.

operator.length_hint(obj, default=0)

Return an estimated length for the object obj. First try to return its actual length, then an estimate using object.__length_hint__(), and finally return the default value.

Added in version 3.4.

The following operation works with callables:

operator.call(obj, /, *args, **kwargs)

operator.__call__(obj, /, *args, **kwargs)

Return obj(*args, **kwargs).

Added in version 3.11.

operator 모듈은 일반화된 어트리뷰트와 항목 조회를 위한 도구도 정의합니다. 이것은 map(), sorted(), itertools.groupby() 또는 함수 인자를 기대하는 다른 함수의 인자로 사용될 고속 필드 추출기를 만드는 데 유용합니다.

operator.attrgetter(attr)

operator.attrgetter(*attrs)

피연산자에서 attr을 꺼내는 콜러블 객체를 반환합니다. 둘 이상의 어트리뷰트가 요청되면, 어트리뷰트의 튜플을 반환합니다. 어트리뷰트 이름은 점을 포함할 수도 있습니다. 예를 들어:

f = attrgetter('name') 다음에, f(b) 호출은 b.name을 반환합니다.

f = attrgetter('name', 'date') 다음에, f(b) 호출은 (b.name, b.date)를 반환합니다.

f = attrgetter('name.first', 'name.last') 다음에, f(b) 호출은 (b.name.first, b.name.last)를 반환합니다.

다음과 동등합니다:

def attrgetter(*items):
    if any(not isinstance(item, str) for item in items):
        raise TypeError('attribute name must be a string')
    if len(items) == 1:
        attr = items[0]
        def g(obj):
            return resolve_attr(obj, attr)
    else:
        def g(obj):
            return tuple(resolve_attr(obj, attr) for attr in items)
    return g

def resolve_attr(obj, attr):
    for name in attr.split("."):
        obj = getattr(obj, name)
    return obj

operator.itemgetter(item)

operator.itemgetter(*items)

Return a callable object that fetches item from its operand using the operand’s __getitem__() method. If multiple items are specified, returns a tuple of lookup values. For example:

f = itemgetter(2) 다음에, f(r) 호출은 r[2]를 반환합니다.

g = itemgetter(2, 5, 3) 다음에, g(r) 호출은 (r[2], r[5], r[3])을 반환합니다.

다음과 동등합니다:

def itemgetter(*items):
    if len(items) == 1:
        item = items[0]
        def g(obj):
            return obj[item]
    else:
        def g(obj):
            return tuple(obj[item] for item in items)
    return g

The items can be any type accepted by the operand’s __getitem__() method. Dictionaries accept any hashable value. Lists, tuples, and strings accept an index or a slice:

>>> itemgetter(1)('ABCDEFG')
'B'
>>> itemgetter(1, 3, 5)('ABCDEFG')
('B', 'D', 'F')
>>> itemgetter(slice(2, None))('ABCDEFG')
'CDEFG'
>>> soldier = dict(rank='captain', name='dotterbart')
>>> itemgetter('rank')(soldier)
'captain'

튜플 레코드에서 특정 필드를 꺼내기 위해 itemgetter()를 사용하는 예:

>>> inventory = [('apple', 3), ('banana', 2), ('pear', 5), ('orange', 1)]
>>> getcount = itemgetter(1)
>>> list(map(getcount, inventory))
[3, 2, 5, 1]
>>> sorted(inventory, key=getcount)
[('orange', 1), ('banana', 2), ('apple', 3), ('pear', 5)]

operator.methodcaller(name, /, *args, **kwargs)

피연산자에서 name 메서드를 호출하는 콜러블 객체를 반환합니다. 추가 인자 및/또는 키워드 인자가 주어지면, 해당 인자도 메서드에 제공됩니다. 예를 들어:

f = methodcaller('name') 다음에, f(b) 호출은 b.name()을 반환합니다.

f = methodcaller('name', 'foo', bar=1) 다음에, f(b) 호출은 b.name('foo', bar=1)을 반환합니다.

다음과 동등합니다:

def methodcaller(name, /, *args, **kwargs):
    def caller(obj):
        return getattr(obj, name)(*args, **kwargs)
    return caller

연산자를 함수에 매핑하기

이 표는 추상 연산이 파이썬 문법의 연산자 기호와 operator 모듈의 함수로 어떻게 대응되는지를 보여줍니다.

연산

문법

함수

더하기(Addition)

a + b

add(a, b)

이어붙이기(Concatenation)

seq1 + seq2

concat(seq1, seq2)

포함 검사(Containment Test)

obj in seq

contains(seq, obj)

나누기(Division)

a / b

truediv(a, b)

나누기(Division)

a // b

floordiv(a, b)

비트별 논리곱(Bitwise And)

a & b

and_(a, b)

비트별 배타적 논리합(Bitwise Exclusive Or)

a ^ b

xor(a, b)

비트별 반전(Bitwise Inversion)

~ a

invert(a)

비트별 논리합(Bitwise Or)

a | b

or_(a, b)

거듭제곱(Exponentiation)

a ** b

pow(a, b)

아이덴티티(Identity)

a is b

is_(a, b)

아이덴티티(Identity)

a is not b

is_not(a, b)

아이덴티티(Identity)

a is None

is_none(a)

아이덴티티(Identity)

a is not None

is_not_none(a)

인덱싱된 대입(Indexed Assignment)

obj[k] = v

setitem(obj, k, v)

인덱싱된 삭제(Indexed Deletion)

del obj[k]

delitem(obj, k)

인덱싱(Indexing)

obj[k]

getitem(obj, k)

왼쪽으로 시프트(Left Shift)

a << b

lshift(a, b)

모듈로(Modulo)

a % b

mod(a, b)

곱하기(Multiplication)

a * b

mul(a, b)

행렬 곱하기(Matrix Multiplication)

a @ b

matmul(a, b)

부정 (산술)(Negation (Arithmetic))

- a

neg(a)

부정 (논리)(Negation (Logical))

not a

not_(a)

양(Positive)

+ a

pos(a)

오른쪽으로 시프트(Right Shift)

a >> b

rshift(a, b)

슬라이스 대입(Slice Assignment)

seq[i:j] = values

setitem(seq, slice(i, j), values)

슬라이스 삭제(Slice Deletion)

del seq[i:j]

delitem(seq, slice(i, j))

슬라이싱(Slicing)

seq[i:j]

getitem(seq, slice(i, j))

문자열 포매팅(String Formatting)

s % obj

mod(s, obj)

빼기(Subtraction)

a - b

sub(a, b)

진릿값 검사(Truth Test)

obj

truth(obj)

대소비교(Ordering)

a < b

lt(a, b)

대소비교(Ordering)

a <= b

le(a, b)

동등성(Equality)

a == b

eq(a, b)

다름(Difference)

a != b

ne(a, b)

대소비교(Ordering)

a >= b

ge(a, b)

대소비교(Ordering)

a > b

gt(a, b)

제자리 연산자

많은 연산에는 “제자리(in-place)” 버전이 있습니다. 아래에 나열된 것들은 일반적인 문법보다 제자리 연산자에 대한 더 기본적인 액세스를 제공하는 함수입니다; 예를 들어, 문장 x += y는 x = operator.iadd(x, y)와 동등합니다. 또 다른 식으로는, z = operator.iadd(x, y)가 복합문 z = x; z += y와 동등하다고 말하는 것입니다.

이 예제들에서, 제자리 메서드가 호출될 때, 계산과 대입이 두 개의 분리된 단계에서 수행된다는 점에 유의하십시오. 아래 나열된 제자리 함수는 제자리 메서드를 호출하는 첫 번째 단계만 수행합니다. 두 번째 단계인 대입은 처리되지 않습니다.

문자열, 숫자 및 튜플과 같은 불변 대상의 경우, 갱신된 값이 계산되지만, 입력 변수에 다시 할당되지 않습니다:

>>> a = 'hello'
>>> iadd(a, ' world')
'hello world'
>>> a
'hello'

리스트와 딕셔너리 같은 가변 대상의 경우, 제자리 메서드가 갱신을 수행하므로, 이후 대입이 필요하지 않습니다:

>>> s = ['h', 'e', 'l', 'l', 'o']
>>> iadd(s, [' ', 'w', 'o', 'r', 'l', 'd'])
['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
>>> s
['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']

operator.iadd(a, b)

operator.__iadd__(a, b)

a = iadd(a, b)는 a += b와 동등합니다.

operator.iand(a, b)

operator.__iand__(a, b)

a = iand(a, b)는 a &= b와 동등합니다.

operator.iconcat(a, b)

operator.__iconcat__(a, b)

a와 b 시퀀스에 대해, a = iconcat(a, b)는 a += b와 동등합니다.

operator.ifloordiv(a, b)

operator.__ifloordiv__(a, b)

a = ifloordiv(a, b)는 a //= b와 동등합니다.

operator.ilshift(a, b)

operator.__ilshift__(a, b)

a = ilshift(a, b)는 a <<= b와 동등합니다.

operator.imod(a, b)

operator.__imod__(a, b)

a = imod(a, b)는 a %= b와 동등합니다.

operator.imul(a, b)

operator.__imul__(a, b)

a = imul(a, b)는 a *= b와 동등합니다.

operator.imatmul(a, b)

operator.__imatmul__(a, b)

a = imatmul(a, b)는 a @= b와 동등합니다.

Added in version 3.5.

operator.ior(a, b)

operator.__ior__(a, b)

a = ior(a, b)는 a |= b와 동등합니다.

operator.ipow(a, b)

operator.__ipow__(a, b)

a = ipow(a, b)는 a **= b와 동등합니다.

operator.irshift(a, b)

operator.__irshift__(a, b)

a = irshift(a, b)는 a >>= b와 동등합니다.

operator.isub(a, b)

operator.__isub__(a, b)

a = isub(a, b)는 a -= b와 동등합니다.

operator.itruediv(a, b)

operator.__itruediv__(a, b)

a = itruediv(a, b)는 a /= b와 동등합니다.

operator.ixor(a, b)

operator.__ixor__(a, b)

a = ixor(a, b)는 a ^= b와 동등합니다.

파일과 디렉터리 액세스

이 장에서 설명하는 모듈은 디스크 파일과 디렉터리를 다룹니다. 예를 들어, 파일의 속성을 읽고, 이식성 있는 방식으로 경로를 조작하고, 임시 파일을 만드는 모듈이 있습니다. 이 장의 전체 모듈 목록은 다음과 같습니다:

pathlib — Object-oriented filesystem paths

기본 사용

Exceptions

UnsupportedOperation

순수한 경로

PurePath

PurePosixPath

PureWindowsPath

일반 속성

연산자

개별 부분에 액세스하기

parts

메서드와 프로퍼티

parser

drive

root

anchor

parents

parent

name

suffix

suffixes

stem

as_posix()

is_absolute()

is_relative_to()

is_reserved()

joinpath()

full_match()

match()

relative_to()

with_name()

with_stem()

with_suffix()

with_segments()

구상 경로

Path

PosixPath

WindowsPath

Parsing and generating URIs

from_uri()

as_uri()

Expanding and resolving paths

home()

expanduser()

cwd()

absolute()

resolve()

readlink()

Querying file type and status

stat()

lstat()

exists()

is_file()

is_dir()

is_symlink()

is_junction()

is_mount()

is_socket()

is_fifo()

is_block_device()

is_char_device()

samefile()

Reading and writing files

open()

read_text()

read_bytes()

write_text()

write_bytes()

Reading directories

iterdir()

scandir()

glob()

rglob()

walk()

Creating files and directories

touch()

mkdir()

symlink_to()

hardlink_to()

Copying, moving and deleting

copy()

copy_into()

rename()

replace()

move()

move_into()

unlink()

rmdir()

Permissions and ownership

owner()

group()

chmod()

lchmod()

Pattern language

Comparison to the glob module

Comparison to the os and os.path modules

Corresponding tools

os.path — Common pathname manipulations

abspath()

basename()

commonpath()

commonprefix()

dirname()

exists()

lexists()

expanduser()

expandvars()

getatime()

getmtime()

getctime()

getsize()

isabs()

isfile()

isdir()

isjunction()

islink()

ismount()

isdevdrive()

isreserved()

join()

normcase()

normpath()

realpath()

relpath()

samefile()

sameopenfile()

samestat()

split()

splitdrive()

splitroot()

splitext()

supports_unicode_filenames

fileinput — Iterate over lines from multiple input streams

input()

filename()

fileno()

lineno()

filelineno()

isfirstline()

isstdin()

nextfile()

close()

FileInput

hook_compressed()

hook_encoded()

stat — Interpreting stat() results

S_ISDIR()

S_ISCHR()

S_ISBLK()

S_ISREG()

S_ISFIFO()

S_ISLNK()

S_ISSOCK()

S_ISDOOR()

S_ISPORT()

S_ISWHT()

S_IMODE()

S_IFMT()

filemode()

ST_MODE

ST_INO

ST_DEV

ST_NLINK

ST_UID

ST_GID

ST_SIZE

ST_ATIME

ST_MTIME

ST_CTIME

S_IFSOCK

S_IFLNK

S_IFREG

S_IFBLK

S_IFDIR

S_IFCHR

S_IFIFO

S_IFDOOR

S_IFPORT

S_IFWHT

S_ISUID

S_ISGID

S_ISVTX

S_IRWXU

S_IRUSR

S_IWUSR

S_IXUSR

S_IRWXG

S_IRGRP

S_IWGRP

S_IXGRP

S_IRWXO

S_IROTH

S_IWOTH

S_IXOTH

S_ENFMT

S_IREAD

S_IWRITE

S_IEXEC

UF_SETTABLE

UF_NODUMP

UF_IMMUTABLE

UF_APPEND

UF_OPAQUE

UF_NOUNLINK

UF_COMPRESSED

UF_TRACKED

UF_DATAVAULT

UF_HIDDEN

SF_SETTABLE

SF_SUPPORTED

SF_SYNTHETIC

SF_ARCHIVED

SF_IMMUTABLE

SF_APPEND

SF_RESTRICTED

SF_NOUNLINK

SF_SNAPSHOT

SF_FIRMLINK

SF_DATALESS

FILE_ATTRIBUTE_ARCHIVE

FILE_ATTRIBUTE_COMPRESSED

FILE_ATTRIBUTE_DEVICE

FILE_ATTRIBUTE_DIRECTORY

FILE_ATTRIBUTE_ENCRYPTED

FILE_ATTRIBUTE_HIDDEN

FILE_ATTRIBUTE_INTEGRITY_STREAM

FILE_ATTRIBUTE_NORMAL

FILE_ATTRIBUTE_NOT_CONTENT_INDEXED

FILE_ATTRIBUTE_NO_SCRUB_DATA

FILE_ATTRIBUTE_OFFLINE

FILE_ATTRIBUTE_READONLY

FILE_ATTRIBUTE_REPARSE_POINT

FILE_ATTRIBUTE_SPARSE_FILE

FILE_ATTRIBUTE_SYSTEM

FILE_ATTRIBUTE_TEMPORARY

FILE_ATTRIBUTE_VIRTUAL

IO_REPARSE_TAG_SYMLINK

IO_REPARSE_TAG_MOUNT_POINT

IO_REPARSE_TAG_APPEXECLINK

filecmp — File and Directory Comparisons

cmp()

cmpfiles()

clear_cache()

dircmp 클래스

dircmp

report()

report_partial_closure()

report_full_closure()

left

right

left_list

right_list

common

left_only

right_only

common_dirs

common_files

common_funny

same_files

diff_files

funny_files

subdirs

DEFAULT_IGNORES

tempfile — Generate temporary files and directories

TemporaryFile()

NamedTemporaryFile()

SpooledTemporaryFile

rollover()

TemporaryDirectory

name

cleanup()

mkstemp()

mkdtemp()

gettempdir()

gettempdirb()

gettempprefix()

gettempprefixb()

tempdir

예

폐지된 함수와 변수

mktemp()

glob — Unix style pathname pattern expansion

glob()

iglob()

escape()

translate()

Examples

fnmatch — Unix filename pattern matching

fnmatch()

fnmatchcase()

filter()

translate()

linecache — Random access to text lines

getline()

clearcache()

checkcache()

lazycache()

shutil — High-level file operations

디렉터리와 파일 연산

copyfileobj()

copyfile()

SameFileError

copymode()

copystat()

copy()

copy2()

ignore_patterns()

copytree()

rmtree()

avoids_symlink_attacks

move()

disk_usage()

chown()

which()

Error

플랫폼 의존적 효율적인 복사 연산

copytree 예

rmtree 예

아카이브 연산

make_archive()

get_archive_formats()

register_archive_format()

unregister_archive_format()

unpack_archive()

register_unpack_format()

unregister_unpack_format()

get_unpack_formats()

아카이브 예

base_dir을 사용한 아카이브 예

출력 터미널의 크기 조회하기

get_terminal_size()

더 보기

모듈 os

운영 체제 인터페이스. 파이썬 파일 객체보다 저수준으로 파일을 다루는 함수를 포함합니다.

모듈 io

파이썬의 내장 I/O 라이브러리. 추상 클래스와 파일 I/O와 같은 구상 클래스를 모두 포함합니다.

내장 함수 open()

파이썬으로 읽고 쓰기 위해 파일을 여는 표준 방법.

pathlib — Object-oriented filesystem paths

Added in version 3.4.

Source code: Lib/pathlib/ [https://github.com/python/cpython/tree/main/Lib/pathlib/]

이 모듈은 다른 운영 체제에 적합한 의미 체계를 가진 파일 시스템 경로를 나타내는 클래스를 제공합니다. 경로 클래스는 I/O 없이 순수한 계산 연산을 제공하는 순수한 경로와 순수한 경로를 상속하지만, I/O 연산도 제공하는 구상 경로로 구분됩니다.

이전에 이 모듈을 사용한 적이 없거나 어떤 클래스가 작업에 적합한지 확신이 없다면, Path가 가장 적합할 가능성이 높습니다. 코드가 실행되는 플랫폼의 구상 경로를 인스턴스화 합니다.

순수한 경로는 특별한 경우에 유용합니다; 예를 들면:

유닉스 기계에서 윈도우 경로를 조작하려고 할 때 (또는 그 반대). 유닉스에서 실행할 때는 WindowsPath를 인스턴스화 할 수 없지만, PureWindowsPath는 인스턴스화 할 수 있습니다.

코드가 실제로 OS에 액세스하지 않고 경로만 조작한다는 확신이 필요할 때. 이 경우, 순수 클래스 중 하나를 인스턴스화 하면 OS 액세스 연산이 없어서 유용 할 수 있습니다.

더 보기

PEP 428 [https://peps.python.org/pep-0428/]: pathlib 모듈 – 객체 지향 파일 시스템 경로.

더 보기

문자열에 대한 저수준 경로 조작을 위해, os.path 모듈을 사용할 수도 있습니다.

기본 사용

메인 클래스 임포트 하기:

>>> from pathlib import Path

서브 디렉터리 나열하기:

>>> p = Path('.')
>>> [x for x in p.iterdir() if x.is_dir()]
[PosixPath('.hg'), PosixPath('docs'), PosixPath('dist'),
 PosixPath('__pycache__'), PosixPath('build')]

이 디렉터리 트리에 있는 파이썬 소스 파일 나열하기:

>>> list(p.glob('**/*.py'))
[PosixPath('test_pathlib.py'), PosixPath('setup.py'),
 PosixPath('pathlib.py'), PosixPath('docs/conf.py'),
 PosixPath('build/lib/pathlib.py')]

디렉터리 트리 내에서 탐색하기:

>>> p = Path('/etc')
>>> q = p / 'init.d' / 'reboot'
>>> q
PosixPath('/etc/init.d/reboot')
>>> q.resolve()
PosixPath('/etc/rc.d/init.d/halt')

경로 속성 조회하기:

>>> q.exists()
True
>>> q.is_dir()
False

파일 열기:

>>> with q.open() as f: f.readline()
...
'#!/bin/bash\n'

Exceptions

exception pathlib.UnsupportedOperation

An exception inheriting NotImplementedError that is raised when an unsupported operation is called on a path object.

Added in version 3.13.

순수한 경로

순수한 경로 객체는 실제로 파일 시스템에 액세스하지 않는 경로 처리 연산을 제공합니다. 이 클래스에 액세스하는 방법에는 세 가지가 있으며, 플레이버(flavours)라고도 부릅니다:

class pathlib.PurePath(*pathsegments)

시스템의 경로 플레이버를 나타내는 일반 클래스 (인스턴스화 하면 PurePosixPath나 PureWindowsPath를 만듭니다):

>>> PurePath('setup.py')      # Running on a Unix machine
PurePosixPath('setup.py')

Each element of pathsegments can be either a string representing a path segment, or an object implementing the os.PathLike interface where the __fspath__() method returns a string, such as another path object:

>>> PurePath('foo', 'some/path', 'bar')
PurePosixPath('foo/some/path/bar')
>>> PurePath(Path('foo'), Path('bar'))
PurePosixPath('foo/bar')

pathsegments가 비어 있으면, 현재 디렉터리를 가정합니다:

>>> PurePath()
PurePosixPath('.')

If a segment is an absolute path, all previous segments are ignored (like os.path.join()):

>>> PurePath('/etc', '/usr', 'lib64')
PurePosixPath('/usr/lib64')
>>> PureWindowsPath('c:/Windows', 'd:bar')
PureWindowsPath('d:bar')

On Windows, the drive is not reset when a rooted relative path segment (e.g., r'\foo') is encountered:

>>> PureWindowsPath('c:/Windows', '/Program Files')
PureWindowsPath('c:/Program Files')

Spurious slashes and single dots are collapsed, but double dots ('..') and leading double slashes ('//') are not, since this would change the meaning of a path for various reasons (e.g. symbolic links, UNC paths):

>>> PurePath('foo//bar')
PurePosixPath('foo/bar')
>>> PurePath('//foo/bar')
PurePosixPath('//foo/bar')
>>> PurePath('foo/./bar')
PurePosixPath('foo/bar')
>>> PurePath('foo/../bar')
PurePosixPath('foo/../bar')

(나이브한 접근법은 PurePosixPath('foo/../bar')를 PurePosixPath('bar')와 동등하게 만드는데, foo가 다른 디렉터리에 대한 심볼릭 링크일 때는 잘못됩니다)

순수한 경로 객체는 os.PathLike 인터페이스를 구현하여, 이 인터페이스가 허용되는 모든 위치에서 사용할 수 있습니다.

버전 3.6에서 변경: os.PathLike 인터페이스에 대한 지원이 추가되었습니다.

class pathlib.PurePosixPath(*pathsegments)

PurePath의 서브 클래스, 이 경로 플레이버는 윈도우 이외의 파일 시스템 경로를 나타냅니다:

>>> PurePosixPath('/etc/hosts')
PurePosixPath('/etc/hosts')

pathsegments는 PurePath와 유사하게 지정됩니다.

class pathlib.PureWindowsPath(*pathsegments)

A subclass of PurePath, this path flavour represents Windows filesystem paths, including UNC paths [https://en.wikipedia.org/wiki/Path_(computing)#UNC]:

>>> PureWindowsPath('c:/', 'Users', 'Ximénez')
PureWindowsPath('c:/Users/Ximénez')
>>> PureWindowsPath('//server/share/file')
PureWindowsPath('//server/share/file')

pathsegments는 PurePath와 유사하게 지정됩니다.

실행 중인 시스템과 관계없이, 이러한 모든 클래스를 인스턴스화 할 수 있는데, 시스템 호출을 수행하는 연산을 제공하지 않기 때문입니다.

일반 속성

Paths are immutable and hashable. Paths of a same flavour are comparable and orderable. These properties respect the flavour’s case-folding semantics:

>>> PurePosixPath('foo') == PurePosixPath('FOO')
False
>>> PureWindowsPath('foo') == PureWindowsPath('FOO')
True
>>> PureWindowsPath('FOO') in { PureWindowsPath('foo') }
True
>>> PureWindowsPath('C:') < PureWindowsPath('d:')
True

다른 플레이버의 경로는 다르다고 비교되며 대소 비교할 수 없습니다:

>>> PureWindowsPath('foo') == PurePosixPath('foo')
False
>>> PureWindowsPath('foo') < PurePosixPath('foo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: '<' not supported between instances of 'PureWindowsPath' and 'PurePosixPath'

연산자

The slash operator helps create child paths, like os.path.join(). If the argument is an absolute path, the previous path is ignored. On Windows, the drive is not reset when the argument is a rooted relative path (e.g., r'\foo'):

>>> p = PurePath('/etc')
>>> p
PurePosixPath('/etc')
>>> p / 'init.d' / 'apache2'
PurePosixPath('/etc/init.d/apache2')
>>> q = PurePath('bin')
>>> '/usr' / q
PurePosixPath('/usr/bin')
>>> p / '/an_absolute_path'
PurePosixPath('/an_absolute_path')
>>> PureWindowsPath('c:/Windows', '/Program Files')
PureWindowsPath('c:/Program Files')

경로 객체는 os.PathLike을 구현하는 객체가 허용되는 모든 곳에서 사용할 수 있습니다:

>>> import os
>>> p = PurePath('/etc')
>>> os.fspath(p)
'/etc'

경로의 문자열 표현은 원시 파일 시스템 경로 자체(네이티브 형식으로, 예를 들어 윈도우에서 역 슬래시)로, 파일 경로를 문자열로 받아들이는 모든 함수에 전달할 수 있습니다:

>>> p = PurePath('/etc')
>>> str(p)
'/etc'
>>> p = PureWindowsPath('c:/Program Files')
>>> str(p)
'c:\\Program Files'

마찬가지로, 경로에 대해 bytes를 호출하면 os.fsencode()로 인코딩된 바이트열 객체로 원시 파일 시스템 경로를 제공합니다:

>>> bytes(p)
b'/etc'

참고

bytes 호출은 유닉스에서만 권장됩니다. 윈도우에서, 유니코드 형식이 파일 시스템 경로의 규범적(canonical) 표현입니다.

개별 부분에 액세스하기

경로의 개별 “부분”(구성 요소)에 액세스하려면, 다음 프로퍼티를 사용하십시오:

PurePath.parts

경로의 다양한 구성 요소로의 액세스를 제공하는 튜플:

>>> p = PurePath('/usr/bin/python3')
>>> p.parts
('/', 'usr', 'bin', 'python3')

>>> p = PureWindowsPath('c:/Program Files/PSF')
>>> p.parts
('c:\\', 'Program Files', 'PSF')

(드라이브와 로컬 루트가 단일 부분으로 다시 그룹화되는 방식에 유의하십시오)

메서드와 프로퍼티

순수한 경로는 다음과 같은 메서드와 프로퍼티를 제공합니다:

PurePath.parser

The implementation of the os.path module used for low-level path parsing and joining: either posixpath or ntpath.

Added in version 3.13.

PurePath.drive

드라이브 문자나 이름을 나타내는 문자열, 있다면:

>>> PureWindowsPath('c:/Program Files/').drive
'c:'
>>> PureWindowsPath('/Program Files/').drive
''
>>> PurePosixPath('/etc').drive
''

UNC 공유도 드라이브로 간주합니다:

>>> PureWindowsPath('//host/share/foo.txt').drive
'\\\\host\\share'

PurePath.root

(로컬이나 글로벌) 루트를 나타내는 문자열, 있다면:

>>> PureWindowsPath('c:/Program Files/').root
'\\'
>>> PureWindowsPath('c:Program Files/').root
''
>>> PurePosixPath('/etc').root
'/'

UNC 공유에는 항상 루트가 있습니다:

>>> PureWindowsPath('//host/share').root
'\\'

If the path starts with more than two successive slashes, PurePosixPath collapses them:

>>> PurePosixPath('//etc').root
'//'
>>> PurePosixPath('///etc').root
'/'
>>> PurePosixPath('////etc').root
'/'

참고

This behavior conforms to The Open Group Base Specifications Issue 6, paragraph 4.11 Pathname Resolution [https://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_11]:

“A pathname that begins with two successive slashes may be interpreted in an implementation-defined manner, although more than two leading slashes shall be treated as a single slash.”

PurePath.anchor

드라이브와 루트의 이어 붙이기:

>>> PureWindowsPath('c:/Program Files/').anchor
'c:\\'
>>> PureWindowsPath('c:Program Files/').anchor
'c:'
>>> PurePosixPath('/etc').anchor
'/'
>>> PureWindowsPath('//host/share').anchor
'\\\\host\\share\\'

PurePath.parents

경로의 논리적 조상에 대한 액세스를 제공하는 불변 시퀀스:

>>> p = PureWindowsPath('c:/foo/bar/setup.py')
>>> p.parents[0]
PureWindowsPath('c:/foo/bar')
>>> p.parents[1]
PureWindowsPath('c:/foo')
>>> p.parents[2]
PureWindowsPath('c:/')

버전 3.10에서 변경: The parents sequence now supports slices and negative index values.

PurePath.parent

경로의 논리적 부모:

>>> p = PurePosixPath('/a/b/c/d')
>>> p.parent
PurePosixPath('/a/b/c')

앵커나 빈 경로를 넘어갈 수 없습니다:

>>> p = PurePosixPath('/')
>>> p.parent
PurePosixPath('/')
>>> p = PurePosixPath('.')
>>> p.parent
PurePosixPath('.')

참고

이것은 순수한 어휘(lexical) 연산이라서, 다음과 같이 동작합니다:

>>> p = PurePosixPath('foo/..')
>>> p.parent
PurePosixPath('foo')

If you want to walk an arbitrary filesystem path upwards, it is recommended to first call Path.resolve() so as to resolve symlinks and eliminate ".." components.

PurePath.name

드라이브와 루트를 제외하고, 마지막 경로 구성 요소를 나타내는 문자열, 있다면:

>>> PurePosixPath('my/library/setup.py').name
'setup.py'

UNC 드라이브 이름은 고려되지 않습니다:

>>> PureWindowsPath('//some/share/setup.py').name
'setup.py'
>>> PureWindowsPath('//some/share').name
''

PurePath.suffix

The last dot-separated portion of the final component, if any:

>>> PurePosixPath('my/library/setup.py').suffix
'.py'
>>> PurePosixPath('my/library.tar.gz').suffix
'.gz'
>>> PurePosixPath('my/library').suffix
''

This is commonly called the file extension.

버전 3.14에서 변경: A single dot (”.”) is considered a valid suffix.

PurePath.suffixes

A list of the path’s suffixes, often called file extensions:

>>> PurePosixPath('my/library.tar.gar').suffixes
['.tar', '.gar']
>>> PurePosixPath('my/library.tar.gz').suffixes
['.tar', '.gz']
>>> PurePosixPath('my/library').suffixes
[]

버전 3.14에서 변경: A single dot (”.”) is considered a valid suffix.

PurePath.stem

suffix가 없는, 마지막 경로 구성 요소:

>>> PurePosixPath('my/library.tar.gz').stem
'library.tar'
>>> PurePosixPath('my/library.tar').stem
'library'
>>> PurePosixPath('my/library').stem
'library'

PurePath.as_posix()

슬래시(/)가 있는 경로의 문자열 표현을 반환합니다:

>>> p = PureWindowsPath('c:\\windows')
>>> str(p)
'c:\\windows'
>>> p.as_posix()
'c:/windows'

PurePath.is_absolute()

경로가 절대적인지 아닌지를 반환합니다. 루트와 (플레이버가 허락하면) 드라이브가 모두 있으면 경로를 절대적이라고 간주합니다:

>>> PurePosixPath('/a/b').is_absolute()
True
>>> PurePosixPath('a/b').is_absolute()
False

>>> PureWindowsPath('c:/a/b').is_absolute()
True
>>> PureWindowsPath('/a/b').is_absolute()
False
>>> PureWindowsPath('c:').is_absolute()
False
>>> PureWindowsPath('//some/share').is_absolute()
True

PurePath.is_relative_to(other)

이 경로가 other 경로에 상대적인지를 반환합니다.

>>> p = PurePath('/etc/passwd')
>>> p.is_relative_to('/etc')
True
>>> p.is_relative_to('/usr')
False

This method is string-based; it neither accesses the filesystem nor treats “..” segments specially. The following code is equivalent:

>>> u = PurePath('/usr')
>>> u == p or u in p.parents
False

Added in version 3.9.

Deprecated since version 3.12, removed in version 3.14: Passing additional arguments is deprecated; if supplied, they are joined with other.

PurePath.is_reserved()

PureWindowsPath에서는, 경로를 윈도우에서 예약된 것으로 간주하면 True를, 그렇지 않으면 False를 반환합니다. PurePosixPath에서는, 항상 False가 반환됩니다.

버전 3.13에서 변경: Windows path names that contain a colon, or end with a dot or a space, are considered reserved. UNC paths may be reserved.

Deprecated since version 3.13, will be removed in version 3.15: This method is deprecated; use os.path.isreserved() to detect reserved paths on Windows.

PurePath.joinpath(*pathsegments)

Calling this method is equivalent to combining the path with each of the given pathsegments in turn:

>>> PurePosixPath('/etc').joinpath('passwd')
PurePosixPath('/etc/passwd')
>>> PurePosixPath('/etc').joinpath(PurePosixPath('passwd'))
PurePosixPath('/etc/passwd')
>>> PurePosixPath('/etc').joinpath('init.d', 'apache2')
PurePosixPath('/etc/init.d/apache2')
>>> PureWindowsPath('c:').joinpath('/Program Files')
PureWindowsPath('c:/Program Files')

PurePath.full_match(pattern, *, case_sensitive=None)

Match this path against the provided glob-style pattern. Return True if matching is successful, False otherwise. For example:

>>> PurePath('a/b.py').full_match('a/*.py')
True
>>> PurePath('a/b.py').full_match('*.py')
False
>>> PurePath('/a/b/c.py').full_match('/a/**')
True
>>> PurePath('/a/b/c.py').full_match('**/*.py')
True

더 보기

Pattern language documentation.

다른 메서드와 마찬가지로, 대소 문자를 구분할지는 플랫폼 기본값을 따릅니다:

>>> PurePosixPath('b.py').full_match('*.PY')
False
>>> PureWindowsPath('b.py').full_match('*.PY')
True

Set case_sensitive to True or False to override this behaviour.

Added in version 3.13.

PurePath.match(pattern, *, case_sensitive=None)

Match this path against the provided non-recursive glob-style pattern. Return True if matching is successful, False otherwise.

This method is similar to full_match(), but empty patterns aren’t allowed (ValueError is raised), the recursive wildcard “**” isn’t supported (it acts like non-recursive “*”), and if a relative pattern is provided, then matching is done from the right:

>>> PurePath('a/b.py').match('*.py')
True
>>> PurePath('/a/b/c.py').match('b/*.py')
True
>>> PurePath('/a/b/c.py').match('a/*.py')
False

버전 3.12에서 변경: The pattern parameter accepts a path-like object.

버전 3.12에서 변경: The case_sensitive parameter was added.

PurePath.relative_to(other, walk_up=False)

Compute a version of this path relative to the path represented by other. If it’s impossible, ValueError is raised:

>>> p = PurePosixPath('/etc/passwd')
>>> p.relative_to('/')
PurePosixPath('etc/passwd')
>>> p.relative_to('/etc')
PurePosixPath('passwd')
>>> p.relative_to('/usr')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pathlib.py", line 941, in relative_to
    raise ValueError(error_message.format(str(self), str(formatted)))
ValueError: '/etc/passwd' is not in the subpath of '/usr' OR one path is relative and the other is absolute.

When walk_up is false (the default), the path must start with other. When the argument is true, .. entries may be added to form the relative path. In all other cases, such as the paths referencing different drives, ValueError is raised.:

>>> p.relative_to('/usr', walk_up=True)
PurePosixPath('../etc/passwd')
>>> p.relative_to('foo', walk_up=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pathlib.py", line 941, in relative_to
    raise ValueError(error_message.format(str(self), str(formatted)))
ValueError: '/etc/passwd' is not on the same drive as 'foo' OR one path is relative and the other is absolute.

경고

This function is part of PurePath and works with strings. It does not check or access the underlying file structure. This can impact the walk_up option as it assumes that no symlinks are present in the path; call resolve() first if necessary to resolve symlinks.

버전 3.12에서 변경: The walk_up parameter was added (old behavior is the same as walk_up=False).

Deprecated since version 3.12, removed in version 3.14: Passing additional positional arguments is deprecated; if supplied, they are joined with other.

PurePath.with_name(name)

name이 변경된 새 경로를 반환합니다. 원래 경로에 이름(name)이 없으면 ValueError가 발생합니다:

>>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
>>> p.with_name('setup.py')
PureWindowsPath('c:/Downloads/setup.py')
>>> p = PureWindowsPath('c:/')
>>> p.with_name('setup.py')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/antoine/cpython/default/Lib/pathlib.py", line 751, in with_name
    raise ValueError("%r has an empty name" % (self,))
ValueError: PureWindowsPath('c:/') has an empty name

PurePath.with_stem(stem)

stem이 변경된 새 경로를 반환합니다. 원래 경로에 이름(name)이 없으면, ValueError가 발생합니다:

>>> p = PureWindowsPath('c:/Downloads/draft.txt')
>>> p.with_stem('final')
PureWindowsPath('c:/Downloads/final.txt')
>>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
>>> p.with_stem('lib')
PureWindowsPath('c:/Downloads/lib.gz')
>>> p = PureWindowsPath('c:/')
>>> p.with_stem('')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/antoine/cpython/default/Lib/pathlib.py", line 861, in with_stem
    return self.with_name(stem + self.suffix)
  File "/home/antoine/cpython/default/Lib/pathlib.py", line 851, in with_name
    raise ValueError("%r has an empty name" % (self,))
ValueError: PureWindowsPath('c:/') has an empty name

Added in version 3.9.

PurePath.with_suffix(suffix)

suffix가 변경된 새 경로를 반환합니다. 원래 경로에 접미사(suffix)가 없으면, 새 suffix가 대신 추가됩니다. suffix가 빈 문자열이면, 원래 접미사가 제거됩니다:

>>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
>>> p.with_suffix('.bz2')
PureWindowsPath('c:/Downloads/pathlib.tar.bz2')
>>> p = PureWindowsPath('README')
>>> p.with_suffix('.txt')
PureWindowsPath('README.txt')
>>> p = PureWindowsPath('README.txt')
>>> p.with_suffix('')
PureWindowsPath('README')

버전 3.14에서 변경: A single dot (”.”) is considered a valid suffix. In previous versions, ValueError is raised if a single dot is supplied.

PurePath.with_segments(*pathsegments)

Create a new path object of the same type by combining the given pathsegments. This method is called whenever a derivative path is created, such as from parent and relative_to(). Subclasses may override this method to pass information to derivative paths, for example:

from pathlib import PurePosixPath

class MyPath(PurePosixPath):
    def __init__(self, *pathsegments, session_id):
        super().__init__(*pathsegments)
        self.session_id = session_id

    def with_segments(self, *pathsegments):
        return type(self)(*pathsegments, session_id=self.session_id)

etc = MyPath('/etc', session_id=42)
hosts = etc / 'hosts'
print(hosts.session_id)  # 42

Added in version 3.12.

구상 경로

구상 경로는 순수한 경로 클래스의 서브 클래스입니다. 후자가 제공하는 연산 외에도, 경로 객체에 대해 시스템 호출을 수행하는 메서드도 제공합니다. 구상 경로를 인스턴스화 하는 세 가지 방법이 있습니다:

class pathlib.Path(*pathsegments)

PurePath의 서브 클래스, 이 클래스는 시스템의 경로 플레이버의 구상 경로를 나타냅니다 (인스턴스화 하면 PosixPath나 WindowsPath를 만듭니다):

>>> Path('setup.py')
PosixPath('setup.py')

pathsegments는 PurePath와 유사하게 지정됩니다.

class pathlib.PosixPath(*pathsegments)

Path와 PurePosixPath의 서브 클래스, 이 클래스는 윈도우 이외의 구상 파일 시스템 경로를 나타냅니다:

>>> PosixPath('/etc/hosts')
PosixPath('/etc/hosts')

pathsegments는 PurePath와 유사하게 지정됩니다.

버전 3.13에서 변경: Raises UnsupportedOperation on Windows. In previous versions, NotImplementedError was raised instead.

class pathlib.WindowsPath(*pathsegments)

Path와 PureWindowsPath의 서브 클래스, 이 클래스는 구상 윈도우 파일 시스템 경로를 나타냅니다:

>>> WindowsPath('c:/', 'Users', 'Ximénez')
WindowsPath('c:/Users/Ximénez')

pathsegments는 PurePath와 유사하게 지정됩니다.

버전 3.13에서 변경: Raises UnsupportedOperation on non-Windows platforms. In previous versions, NotImplementedError was raised instead.

여러분의 시스템에 해당하는 클래스 플레이버만 인스턴스화 할 수 있습니다 (호환되지 않는 경로 플레이버에 대한 시스템 호출을 허용하면 응용 프로그램에서 버그나 실패가 발생할 수 있습니다):

>>> import os
>>> os.name
'posix'
>>> Path('setup.py')
PosixPath('setup.py')
>>> PosixPath('setup.py')
PosixPath('setup.py')
>>> WindowsPath('setup.py')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pathlib.py", line 798, in __new__
    % (cls.__name__,))
UnsupportedOperation: cannot instantiate 'WindowsPath' on your system

Some concrete path methods can raise an OSError if a system call fails (for example because the path doesn’t exist).

Parsing and generating URIs

Concrete path objects can be created from, and represented as, ‘file’ URIs conforming to RFC 8089 [https://datatracker.ietf.org/doc/html/rfc8089.html].

참고

File URIs are not portable across machines with different filesystem encodings.

classmethod Path.from_uri(uri)

Return a new path object from parsing a ‘file’ URI. For example:

>>> p = Path.from_uri('file:///etc/hosts')
PosixPath('/etc/hosts')

On Windows, DOS device and UNC paths may be parsed from URIs:

>>> p = Path.from_uri('file:///c:/windows')
WindowsPath('c:/windows')
>>> p = Path.from_uri('file://server/share')
WindowsPath('//server/share')

Several variant forms are supported:

>>> p = Path.from_uri('file:////server/share')
WindowsPath('//server/share')
>>> p = Path.from_uri('file://///server/share')
WindowsPath('//server/share')
>>> p = Path.from_uri('file:c:/windows')
WindowsPath('c:/windows')
>>> p = Path.from_uri('file:/c|/windows')
WindowsPath('c:/windows')

ValueError is raised if the URI does not start with file:, or the parsed path isn’t absolute.

Added in version 3.13.

Path.as_uri()

Represent the path as a ‘file’ URI. ValueError is raised if the path isn’t absolute.

>>> p = PosixPath('/etc/passwd')
>>> p.as_uri()
'file:///etc/passwd'
>>> p = WindowsPath('c:/Windows')
>>> p.as_uri()
'file:///c:/Windows'

For historical reasons, this method is also available from PurePath objects. However, its use of os.fsencode() makes it strictly impure.

Expanding and resolving paths

classmethod Path.home()

Return a new path object representing the user’s home directory (as returned by os.path.expanduser() with ~ construct). If the home directory can’t be resolved, RuntimeError is raised.

>>> Path.home()
PosixPath('/home/antoine')

Added in version 3.5.

Path.expanduser()

Return a new path with expanded ~ and ~user constructs, as returned by os.path.expanduser(). If a home directory can’t be resolved, RuntimeError is raised.

>>> p = PosixPath('~/films/Monty Python')
>>> p.expanduser()
PosixPath('/home/eric/films/Monty Python')

Added in version 3.5.

classmethod Path.cwd()

현재 디렉터리를 나타내는 새 경로 객체를 반환합니다. os.getcwd()가 반환하는 것과 유사합니다:

>>> Path.cwd()
PosixPath('/home/antoine/pathlib')

Path.absolute()

Make the path absolute, without normalization or resolving symlinks. Returns a new path object:

>>> p = Path('tests')
>>> p
PosixPath('tests')
>>> p.absolute()
PosixPath('/home/antoine/pathlib/tests')

Path.resolve(strict=False)

심볼릭 링크를 결정하여, 경로를 절대적으로 만듭니다. 새로운 경로 객체가 반환됩니다:

>>> p = Path()
>>> p
PosixPath('.')
>>> p.resolve()
PosixPath('/home/antoine/pathlib')

“..” 구성 요소도 제거됩니다 (이것이 이렇게 하는 유일한 메서드입니다):

>>> p = Path('docs/../setup.py')
>>> p.resolve()
PosixPath('/home/antoine/pathlib/setup.py')

If a path doesn’t exist or a symlink loop is encountered, and strict is True, OSError is raised. If strict is False, the path is resolved as far as possible and any remainder is appended without checking whether it exists.

버전 3.6에서 변경: The strict parameter was added (pre-3.6 behavior is strict).

버전 3.13에서 변경: Symlink loops are treated like other errors: OSError is raised in strict mode, and no exception is raised in non-strict mode. In previous versions, RuntimeError is raised no matter the value of strict.

Path.readlink()

심볼릭 링크가 가리키는 경로를 반환합니다 (os.readlink()가 반환하는 것과 유사합니다):

>>> p = Path('mylink')
>>> p.symlink_to('setup.py')
>>> p.readlink()
PosixPath('setup.py')

Added in version 3.9.

버전 3.13에서 변경: Raises UnsupportedOperation if os.readlink() is not available. In previous versions, NotImplementedError was raised.

Querying file type and status

버전 3.8에서 변경: exists(), is_dir(), is_file(), is_mount(), is_symlink(), is_block_device(), is_char_device(), is_fifo(), is_socket() now return False instead of raising an exception for paths that contain characters unrepresentable at the OS level.

버전 3.14에서 변경: The methods given above now return False instead of raising any OSError exception from the operating system. In previous versions, some kinds of OSError exception are raised, and others suppressed. The new behaviour is consistent with os.path.exists(), os.path.isdir(), etc. Use stat() to retrieve the file status without suppressing exceptions.

Path.stat(*, follow_symlinks=True)

Return an os.stat_result object containing information about this path, like os.stat(). The result is looked up at each call to this method.

This method normally follows symlinks; to stat a symlink add the argument follow_symlinks=False, or use lstat().

>>> p = Path('setup.py')
>>> p.stat().st_size
956
>>> p.stat().st_mtime
1327883547.852554

버전 3.10에서 변경: The follow_symlinks parameter was added.

Path.lstat()

Path.stat()과 비슷하지만, 경로가 심볼릭 링크를 가리키면, 대상이 아닌 심볼릭 링크의 정보를 반환합니다.

Path.exists(*, follow_symlinks=True)

Return True if the path points to an existing file or directory. False will be returned if the path is invalid, inaccessible or missing. Use Path.stat() to distinguish between these cases.

This method normally follows symlinks; to check if a symlink exists, add the argument follow_symlinks=False.

>>> Path('.').exists()
True
>>> Path('setup.py').exists()
True
>>> Path('/etc').exists()
True
>>> Path('nonexistentfile').exists()
False

버전 3.12에서 변경: The follow_symlinks parameter was added.

Path.is_file(*, follow_symlinks=True)

Return True if the path points to a regular file. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a regular file. Use Path.stat() to distinguish between these cases.

This method normally follows symlinks; to exclude symlinks, add the argument follow_symlinks=False.

버전 3.13에서 변경: The follow_symlinks parameter was added.

Path.is_dir(*, follow_symlinks=True)

Return True if the path points to a directory. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a directory. Use Path.stat() to distinguish between these cases.

This method normally follows symlinks; to exclude symlinks to directories, add the argument follow_symlinks=False.

버전 3.13에서 변경: The follow_symlinks parameter was added.

Path.is_symlink()

Return True if the path points to a symbolic link, even if that symlink is broken. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a symbolic link. Use Path.stat() to distinguish between these cases.

Path.is_junction()

Return True if the path points to a junction, and False for any other type of file. Currently only Windows supports junctions.

Added in version 3.12.

Path.is_mount()

Return True if the path is a mount point: a point in a file system where a different file system has been mounted. On POSIX, the function checks whether path’s parent, path/.., is on a different device than path, or whether path/.. and path point to the same i-node on the same device — this should detect mount points for all Unix and POSIX variants. On Windows, a mount point is considered to be a drive letter root (e.g. c:\), a UNC share (e.g. \\server\share), or a mounted filesystem directory.

Added in version 3.7.

버전 3.12에서 변경: Windows support was added.

Path.is_socket()

Return True if the path points to a Unix socket. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a Unix socket. Use Path.stat() to distinguish between these cases.

Path.is_fifo()

Return True if the path points to a FIFO. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a FIFO. Use Path.stat() to distinguish between these cases.

Path.is_block_device()

Return True if the path points to a block device. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a block device. Use Path.stat() to distinguish between these cases.

Path.is_char_device()

Return True if the path points to a character device. False will be returned if the path is invalid, inaccessible or missing, or if it points to something other than a character device. Use Path.stat() to distinguish between these cases.

Path.samefile(other_path)

이 경로가 other_path와 같은 파일을 가리키는지를 반환합니다. other_path는 Path 객체이거나 문자열일 수 있습니다. 의미는 os.path.samefile()과 os.path.samestat()과 유사합니다.

어떤 이유로 파일에 액세스할 수 없으면 OSError가 발생할 수 있습니다.

>>> p = Path('spam')
>>> q = Path('eggs')
>>> p.samefile(q)
False
>>> p.samefile('spam')
True

Added in version 3.5.

Reading and writing files

Path.open(mode='r', buffering=-1, encoding=None, errors=None, newline=None)

내장 open() 함수처럼, 경로가 가리키는 파일을 엽니다:

>>> p = Path('setup.py')
>>> with p.open() as f:
...     f.readline()
...
'#!/usr/bin/env python3\n'

Path.read_text(encoding=None, errors=None, newline=None)

가리키는 파일의 디코딩된 내용을 문자열로 반환합니다:

>>> p = Path('my_text_file')
>>> p.write_text('Text file contents')
18
>>> p.read_text()
'Text file contents'

파일이 열린 다음에 닫힙니다. 선택적 매개 변수는 open()과 같은 의미입니다.

Added in version 3.5.

버전 3.13에서 변경: The newline parameter was added.

Path.read_bytes()

가리키는 파일의 바이너리 내용을 바이트열 객체로 반환합니다:

>>> p = Path('my_binary_file')
>>> p.write_bytes(b'Binary file contents')
20
>>> p.read_bytes()
b'Binary file contents'

Added in version 3.5.

Path.write_text(data, encoding=None, errors=None, newline=None)

가리키는 파일을 텍스트 모드로 열고, data를 쓴 다음, 파일을 닫습니다:

>>> p = Path('my_text_file')
>>> p.write_text('Text file contents')
18
>>> p.read_text()
'Text file contents'

같은 이름의 기존 파일을 덮어씁니다. 선택적 매개 변수는 open()에서와 같은 의미입니다.

Added in version 3.5.

버전 3.10에서 변경: The newline parameter was added.

Path.write_bytes(data)

가리키는 파일을 바이너리 모드로 열고, data를 쓴 다음, 파일을 닫습니다:

>>> p = Path('my_binary_file')
>>> p.write_bytes(b'Binary file contents')
20
>>> p.read_bytes()
b'Binary file contents'

같은 이름의 기존 파일을 덮어씁니다.

Added in version 3.5.

Reading directories

Path.iterdir()

경로가 디렉터리를 가리킬 때, 디렉터리 내용의 경로 객체를 산출합니다:

>>> p = Path('docs')
>>> for child in p.iterdir(): child
...
PosixPath('docs/conf.py')
PosixPath('docs/_templates')
PosixPath('docs/make.bat')
PosixPath('docs/index.rst')
PosixPath('docs/_build')
PosixPath('docs/_static')
PosixPath('docs/Makefile')

The children are yielded in arbitrary order, and the special entries '.' and '..' are not included. If a file is removed from or added to the directory after creating the iterator, it is unspecified whether a path object for that file is included.

If the path is not a directory or otherwise inaccessible, OSError is raised.

Path.scandir()

When the path points to a directory, return an iterator of os.DirEntry objects corresponding to entries in the directory. The returned iterator supports the context manager protocol. It is implemented using os.scandir() and gives the same guarantees.

Using scandir() instead of iterdir() can significantly increase the performance of code that also needs file type or file attribute information, because os.DirEntry objects expose this information if the operating system provides it when scanning a directory.

The following example displays the names of subdirectories. The entry.is_dir() check will generally not make an additional system call:

>>> p = Path('docs')
>>> with p.scandir() as entries:
...     for entry in entries:
...         if entry.is_dir():
...             entry.name
...
'_templates'
'_build'
'_static'

Added in version 3.14.

Path.glob(pattern, *, case_sensitive=None, recurse_symlinks=False)

이 경로로 표현되는 디렉터리에서, 주어진 상대 pattern을 glob 하여, 일치하는 모든 파일을 (종류와 관계없이) 산출합니다:

>>> sorted(Path('.').glob('*.py'))
[PosixPath('pathlib.py'), PosixPath('setup.py'), PosixPath('test_pathlib.py')]
>>> sorted(Path('.').glob('*/*.py'))
[PosixPath('docs/conf.py')]
>>> sorted(Path('.').glob('**/*.py'))
[PosixPath('build/lib/pathlib.py'),
 PosixPath('docs/conf.py'),
 PosixPath('pathlib.py'),
 PosixPath('setup.py'),
 PosixPath('test_pathlib.py')]

더 보기

Pattern language documentation.

By default, or when the case_sensitive keyword-only argument is set to None, this method matches paths using platform-specific casing rules: typically, case-sensitive on POSIX, and case-insensitive on Windows. Set case_sensitive to True or False to override this behaviour.

By default, or when the recurse_symlinks keyword-only argument is set to False, this method follows symlinks except when expanding “**” wildcards. Set recurse_symlinks to True to always follow symlinks.

인자 self, pattern으로 감사 이벤트 pathlib.Path.glob을 발생시킵니다.

버전 3.12에서 변경: The case_sensitive parameter was added.

버전 3.13에서 변경: The recurse_symlinks parameter was added.

버전 3.13에서 변경: The pattern parameter accepts a path-like object.

버전 3.13에서 변경: Any OSError exceptions raised from scanning the filesystem are suppressed. In previous versions, such exceptions are suppressed in many cases, but not all.

Path.rglob(pattern, *, case_sensitive=None, recurse_symlinks=False)

Glob the given relative pattern recursively. This is like calling Path.glob() with “**/” added in front of the pattern.

더 보기

Pattern language and Path.glob() documentation.

인자 self, pattern으로 감사 이벤트 pathlib.Path.rglob을 발생시킵니다.

버전 3.12에서 변경: The case_sensitive parameter was added.

버전 3.13에서 변경: The recurse_symlinks parameter was added.

버전 3.13에서 변경: The pattern parameter accepts a path-like object.

Path.walk(top_down=True, on_error=None, follow_symlinks=False)

Generate the file names in a directory tree by walking the tree either top-down or bottom-up.

For each directory in the directory tree rooted at self (including self but excluding ‘.’ and ‘..’), the method yields a 3-tuple of (dirpath, dirnames, filenames).

dirpath is a Path to the directory currently being walked, dirnames is a list of strings for the names of subdirectories in dirpath (excluding '.' and '..'), and filenames is a list of strings for the names of the non-directory files in dirpath. To get a full path (which begins with self) to a file or directory in dirpath, do dirpath / name. Whether or not the lists are sorted is file system-dependent.

If the optional argument top_down is true (which is the default), the triple for a directory is generated before the triples for any of its subdirectories (directories are walked top-down). If top_down is false, the triple for a directory is generated after the triples for all of its subdirectories (directories are walked bottom-up). No matter the value of top_down, the list of subdirectories is retrieved before the triples for the directory and its subdirectories are walked.

When top_down is true, the caller can modify the dirnames list in-place (for example, using del or slice assignment), and Path.walk() will only recurse into the subdirectories whose names remain in dirnames. This can be used to prune the search, or to impose a specific order of visiting, or even to inform Path.walk() about directories the caller creates or renames before it resumes Path.walk() again. Modifying dirnames when top_down is false has no effect on the behavior of Path.walk() since the directories in dirnames have already been generated by the time dirnames is yielded to the caller.

By default, errors from os.scandir() are ignored. If the optional argument on_error is specified, it should be a callable; it will be called with one argument, an OSError instance. The callable can handle the error to continue the walk or re-raise it to stop the walk. Note that the filename is available as the filename attribute of the exception object.

By default, Path.walk() does not follow symbolic links, and instead adds them to the filenames list. Set follow_symlinks to true to resolve symlinks and place them in dirnames and filenames as appropriate for their targets, and consequently visit directories pointed to by symlinks (where supported).

참고

Be aware that setting follow_symlinks to true can lead to infinite recursion if a link points to a parent directory of itself. Path.walk() does not keep track of the directories it has already visited.

참고

Path.walk() assumes the directories it walks are not modified during execution. For example, if a directory from dirnames has been replaced with a symlink and follow_symlinks is false, Path.walk() will still try to descend into it. To prevent such behavior, remove directories from dirnames as appropriate.

참고

Unlike os.walk(), Path.walk() lists symlinks to directories in filenames if follow_symlinks is false.

This example displays the number of bytes used by all files in each directory, while ignoring __pycache__ directories:

from pathlib import Path
for root, dirs, files in Path("cpython/Lib/concurrent").walk(on_error=print):
  print(
      root,
      "consumes",
      sum((root / file).stat().st_size for file in files),
      "bytes in",
      len(files),
      "non-directory files"
  )
  if '__pycache__' in dirs:
        dirs.remove('__pycache__')

This next example is a simple implementation of shutil.rmtree(). Walking the tree bottom-up is essential as rmdir() doesn’t allow deleting a directory before it is empty:

# Delete everything reachable from the directory "top".
# CAUTION:  This is dangerous! For example, if top == Path('/'),
# it could delete all of your files.
for root, dirs, files in top.walk(top_down=False):
    for name in files:
        (root / name).unlink()
    for name in dirs:
        (root / name).rmdir()

Added in version 3.12.

Creating files and directories

Path.touch(mode=0o666, exist_ok=True)

Create a file at this given path. If mode is given, it is combined with the process’s umask value to determine the file mode and access flags. If the file already exists, the function succeeds when exist_ok is true (and its modification time is updated to the current time), otherwise FileExistsError is raised.

더 보기

The open(), write_text() and write_bytes() methods are often used to create files.

Path.mkdir(mode=0o777, parents=False, exist_ok=False)

Create a new directory at this given path. If mode is given, it is combined with the process’s umask value to determine the file mode and access flags. If the path already exists, FileExistsError is raised.

parents가 참이면, 이 경로의 누락 된 부모를 필요하면 만듭니다; 이것들은 mode를 고려하지 않고 기본 권한으로 만들어집니다 (POSIX mkdir -p 명령을 모방합니다).

parents가 거짓(기본값)이면, 누락된 부모가 FileNotFoundError를 발생시킵니다.

exist_ok가 거짓(기본값)이면, 대상 디렉터리가 이미 존재하면 FileExistsError가 발생합니다.

If exist_ok is true, FileExistsError will not be raised unless the given path already exists in the file system and is not a directory (same behavior as the POSIX mkdir -p command).

버전 3.5에서 변경: exist_ok 매개 변수가 추가되었습니다.

Path.symlink_to(target, target_is_directory=False)

Make this path a symbolic link pointing to target.

On Windows, a symlink represents either a file or a directory, and does not morph to the target dynamically. If the target is present, the type of the symlink will be created to match. Otherwise, the symlink will be created as a directory if target_is_directory is true or a file symlink (the default) otherwise. On non-Windows platforms, target_is_directory is ignored.

>>> p = Path('mylink')
>>> p.symlink_to('setup.py')
>>> p.resolve()
PosixPath('/home/antoine/pathlib/setup.py')
>>> p.stat().st_size
956
>>> p.lstat().st_size
8

참고

인자의 순서(링크, 대상)는 os.symlink()와 반대입니다.

버전 3.13에서 변경: Raises UnsupportedOperation if os.symlink() is not available. In previous versions, NotImplementedError was raised.

Path.hardlink_to(target)

Make this path a hard link to the same file as target.

참고

The order of arguments (link, target) is the reverse of os.link()’s.

Added in version 3.10.

버전 3.13에서 변경: Raises UnsupportedOperation if os.link() is not available. In previous versions, NotImplementedError was raised.

Copying, moving and deleting

Path.copy(target, *, follow_symlinks=True, dirs_exist_ok=False, preserve_metadata=False)

Copy this file or directory tree to the given target, and return a new Path instance pointing to target.

If the source is a file, the target will be replaced if it is an existing file. If the source is a symlink and follow_symlinks is true (the default), the symlink’s target is copied. Otherwise, the symlink is recreated at the destination.

If the source is a directory and dirs_exist_ok is false (the default), a FileExistsError is raised if the target is an existing directory. If dirs_exists_ok is true, the copying operation will overwrite existing files within the destination tree with corresponding files from the source tree.

If preserve_metadata is false (the default), only directory structures and file data are guaranteed to be copied. Set preserve_metadata to true to ensure that file and directory permissions, flags, last access and modification times, and extended attributes are copied where supported. This argument has no effect when copying files on Windows (where metadata is always preserved).

참고

Where supported by the operating system and file system, this method performs a lightweight copy, where data blocks are only copied when modified. This is known as copy-on-write.

Added in version 3.14.

Path.copy_into(target_dir, *, follow_symlinks=True, dirs_exist_ok=False, preserve_metadata=False)

Copy this file or directory tree into the given target_dir, which should be an existing directory. Other arguments are handled identically to Path.copy(). Returns a new Path instance pointing to the copy.

Added in version 3.14.

Path.rename(target)

Rename this file or directory to the given target, and return a new Path instance pointing to target. On Unix, if target exists and is a file, it will be replaced silently if the user has permission. On Windows, if target exists, FileExistsError will be raised. target can be either a string or another path object:

>>> p = Path('foo')
>>> p.open('w').write('some text')
9
>>> target = Path('bar')
>>> p.rename(target)
PosixPath('bar')
>>> target.open().read()
'some text'

The target path may be absolute or relative. Relative paths are interpreted relative to the current working directory, not the directory of the Path object.

It is implemented in terms of os.rename() and gives the same guarantees.

버전 3.8에서 변경: Added return value, return the new Path instance.

Path.replace(target)

Rename this file or directory to the given target, and return a new Path instance pointing to target. If target points to an existing file or empty directory, it will be unconditionally replaced.

The target path may be absolute or relative. Relative paths are interpreted relative to the current working directory, not the directory of the Path object.

버전 3.8에서 변경: Added return value, return the new Path instance.

Path.move(target)

Move this file or directory tree to the given target, and return a new Path instance pointing to target.

If the target doesn’t exist it will be created. If both this path and the target are existing files, then the target is overwritten. If both paths point to the same file or directory, or the target is a non-empty directory, then OSError is raised.

If both paths are on the same filesystem, the move is performed with os.replace(). Otherwise, this path is copied (preserving metadata and symlinks) and then deleted.

Added in version 3.14.

Path.move_into(target_dir)

Move this file or directory tree into the given target_dir, which should be an existing directory. Returns a new Path instance pointing to the moved path.

Added in version 3.14.

Path.unlink(missing_ok=False)

이 파일이나 심볼릭 링크를 제거합니다. 경로가 디렉터리를 가리키면, Path.rmdir()을 대신 사용하십시오.

missing_ok가 거짓(기본값)이면, 경로가 없을 때 FileNotFoundError가 발생합니다.

missing_ok가 참이면, FileNotFoundError 예외는 무시됩니다 (POSIX rm -f 명령과 같은 동작).

버전 3.8에서 변경: missing_ok 매개 변수가 추가되었습니다.

Path.rmdir()

이 디렉터리를 제거합니다. 디렉터리는 비어 있어야 합니다.

Permissions and ownership

Path.owner(*, follow_symlinks=True)

Return the name of the user owning the file. KeyError is raised if the file’s user identifier (UID) isn’t found in the system database.

This method normally follows symlinks; to get the owner of the symlink, add the argument follow_symlinks=False.

버전 3.13에서 변경: Raises UnsupportedOperation if the pwd module is not available. In earlier versions, NotImplementedError was raised.

버전 3.13에서 변경: The follow_symlinks parameter was added.

Path.group(*, follow_symlinks=True)

Return the name of the group owning the file. KeyError is raised if the file’s group identifier (GID) isn’t found in the system database.

This method normally follows symlinks; to get the group of the symlink, add the argument follow_symlinks=False.

버전 3.13에서 변경: Raises UnsupportedOperation if the grp module is not available. In earlier versions, NotImplementedError was raised.

버전 3.13에서 변경: The follow_symlinks parameter was added.

Path.chmod(mode, *, follow_symlinks=True)

Change the file mode and permissions, like os.chmod().

This method normally follows symlinks. Some Unix flavours support changing permissions on the symlink itself; on these platforms you may add the argument follow_symlinks=False, or use lchmod().

>>> p = Path('setup.py')
>>> p.stat().st_mode
33277
>>> p.chmod(0o444)
>>> p.stat().st_mode
33060

버전 3.10에서 변경: The follow_symlinks parameter was added.

Path.lchmod(mode)

Path.chmod()와 비슷하지만, 경로가 심볼릭 링크를 가리키면, 대상이 아닌 심볼릭 링크의 모드가 변경됩니다.

Pattern language

The following wildcards are supported in patterns for full_match(), glob() and rglob():

** (entire segment)

Matches any number of file or directory segments, including zero.

* (entire segment)

Matches one file or directory segment.

* (part of a segment)

Matches any number of non-separator characters, including zero.

?

Matches one non-separator character.

[seq]

Matches one character in seq.

[!seq]

Matches one character not in seq.

For a literal match, wrap the meta-characters in brackets. For example, "[?]" matches the character "?".

The “**” wildcard enables recursive globbing. A few examples:

Pattern

Meaning

“**/*”

Any path with at least one segment.

“**/*.py”

Any path with a final segment ending “.py”.

“assets/**”

Any path starting with “assets/”.

“assets/**/*”

Any path starting with “assets/”, excluding “assets/” itself.

참고

Globbing with the “**” wildcard visits every directory in the tree. Large directory trees may take a long time to search.

버전 3.13에서 변경: Globbing with a pattern that ends with “**” returns both files and directories. In previous versions, only directories were returned.

In Path.glob() and rglob(), a trailing slash may be added to the pattern to match only directories.

버전 3.11에서 변경: Globbing with a pattern that ends with a pathname components separator (sep or altsep) returns only directories.

Comparison to the glob module

The patterns accepted and results generated by Path.glob() and Path.rglob() differ slightly from those by the glob module:

Files beginning with a dot are not special in pathlib. This is like passing include_hidden=True to glob.glob().

“**” pattern components are always recursive in pathlib. This is like passing recursive=True to glob.glob().

“**” pattern components do not follow symlinks by default in pathlib. This behaviour has no equivalent in glob.glob(), but you can pass recurse_symlinks=True to Path.glob() for compatible behaviour.

Like all PurePath and Path objects, the values returned from Path.glob() and Path.rglob() don’t include trailing slashes.

The values returned from pathlib’s path.glob() and path.rglob() include the path as a prefix, unlike the results of glob.glob(root_dir=path).

The values returned from pathlib’s path.glob() and path.rglob() may include path itself, for example when globbing “**”, whereas the results of glob.glob(root_dir=path) never include an empty string that would correspond to path.

Comparison to the os and os.path modules

pathlib implements path operations using PurePath and Path objects, and so it’s said to be object-oriented. On the other hand, the os and os.path modules supply functions that work with low-level str and bytes objects, which is a more procedural approach. Some users consider the object-oriented style to be more readable.

Many functions in os and os.path support bytes paths and paths relative to directory descriptors. These features aren’t available in pathlib.

Python’s str and bytes types, and portions of the os and os.path modules, are written in C and are very speedy. pathlib is written in pure Python and is often slower, but rarely slow enough to matter.

pathlib’s path normalization is slightly more opinionated and consistent than os.path. For example, whereas os.path.abspath() eliminates “..” segments from a path, which may change its meaning if symlinks are involved, Path.absolute() preserves these segments for greater safety.

pathlib’s path normalization may render it unsuitable for some applications:

pathlib normalizes Path("my_folder/") to Path("my_folder"), which changes a path’s meaning when supplied to various operating system APIs and command-line utilities. Specifically, the absence of a trailing separator may allow the path to be resolved as either a file or directory, rather than a directory only.

pathlib normalizes Path("./my_program") to Path("my_program"), which changes a path’s meaning when used as an executable search path, such as in a shell or when spawning a child process. Specifically, the absence of a separator in the path may force it to be looked up in PATH rather than the current directory.

As a consequence of these differences, pathlib is not a drop-in replacement for os.path.

Corresponding tools

아래는 다양한 os 함수를 해당 PurePath/Path 대응 물에 매핑하는 표입니다.

os and os.path

pathlib

os.path.dirname()

PurePath.parent

os.path.basename()

PurePath.name

os.path.splitext()

PurePath.stem, PurePath.suffix

os.path.join()

PurePath.joinpath()

os.path.isabs()

PurePath.is_absolute()

os.path.relpath()

PurePath.relative_to() [1]

os.path.expanduser()

Path.expanduser() [2]

os.path.realpath()

Path.resolve()

os.path.abspath()

Path.absolute() [3]

os.path.exists()

Path.exists()

os.path.isfile()

Path.is_file()

os.path.isdir()

Path.is_dir()

os.path.islink()

Path.is_symlink()

os.path.isjunction()

Path.is_junction()

os.path.ismount()

Path.is_mount()

os.path.samefile()

Path.samefile()

os.getcwd()

Path.cwd()

os.stat()

Path.stat()

os.lstat()

Path.lstat()

os.listdir()

Path.iterdir()

os.walk()

Path.walk() [4]

os.mkdir(), os.makedirs()

Path.mkdir()

os.link()

Path.hardlink_to()

os.symlink()

Path.symlink_to()

os.readlink()

Path.readlink()

os.rename()

Path.rename()

os.replace()

Path.replace()

os.remove(), os.unlink()

Path.unlink()

os.rmdir()

Path.rmdir()

os.chmod()

Path.chmod()

os.lchmod()

Path.lchmod()

Footnotes

[1]

os.path.relpath() calls abspath() to make paths absolute and remove “..” parts, whereas PurePath.relative_to() is a lexical operation that raises ValueError when its inputs’ anchors differ (e.g. if one path is absolute and the other relative.)

[2]

os.path.expanduser() returns the path unchanged if the home directory can’t be resolved, whereas Path.expanduser() raises RuntimeError.

[3]

os.path.abspath() removes “..” components without resolving symlinks, which may change the meaning of the path, whereas Path.absolute() leaves any “..” components in the path.

[4]

os.walk() always follows symlinks when categorizing paths into dirnames and filenames, whereas Path.walk() categorizes all symlinks into filenames when follow_symlinks is false (the default.)

os.path — Common pathname manipulations

Source code: Lib/genericpath.py [https://github.com/python/cpython/tree/main/Lib/genericpath.py], Lib/posixpath.py [https://github.com/python/cpython/tree/main/Lib/posixpath.py] (for POSIX) and Lib/ntpath.py [https://github.com/python/cpython/tree/main/Lib/ntpath.py] (for Windows).

This module implements some useful functions on pathnames. To read or write files see open(), and for accessing the filesystem see the os module. The path parameters can be passed as strings, or bytes, or any object implementing the os.PathLike protocol.

Unlike a Unix shell, Python does not do any automatic path expansions. Functions such as expanduser() and expandvars() can be invoked explicitly when an application desires shell-like path expansion. (See also the glob module.)

더 보기

pathlib 모듈은 고수준의 경로 객체를 제공합니다.

참고

이 모든 함수는 매개 변수가 모두 바이트열 객체이거나 모두 문자열 객체인 것만 허락합니다. 경로나 파일 이름이 반환되면, 결과는 같은 형의 객체입니다.

참고

운영 체제마다 경로 이름 규칙이 다르기 때문에, 표준 라이브러리에 이 모듈의 여러 버전이 있습니다. os.path 모듈은 항상 파이썬이 실행 중인 운영 체제에 적합한 경로 모듈이고, 따라서 지역 경로에 사용할 수 있습니다. 그러나, 항상 다른 형식 중 하나인 경로를 조작하려면 개별 모듈을 임포트 해서 사용할 수도 있습니다. 그들은 모두 같은 인터페이스를 가지고 있습니다:

유닉스 스타일 경로는 posixpath

윈도우 경로는 ntpath

버전 3.8에서 변경: exists(), lexists(), isdir(), isfile(), islink() 및 ismount()는 이제 OS 수준에서 표현할 수 없는 문자나 바이트를 포함하는 경로에 대해 예외를 발생시키는 대신 False를 반환합니다.

os.path.abspath(path)

경로명 path의 정규화된 절대 버전을 반환합니다. 대부분의 플랫폼에서, 이는 다음과 같이 normpath() 함수를 호출하는 것과 동등합니다: normpath(join(os.getcwd(), path)).

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.basename(path)

경로명 path의 기본 이름을 반환합니다. 이것은 path를 함수 split()에 전달하여 반환된 쌍의 두 번째 요소입니다. 이 함수의 결과는 유닉스 basename 프로그램과 다름에 유의하십시오; '/foo/bar/'에 대해 basename은 'bar'를 반환하고, basename() 함수는 빈 문자열('')을 반환합니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.commonpath(paths)

Return the longest common sub-path of each pathname in the iterable paths. Raise ValueError if paths contain both absolute and relative pathnames, if paths are on different drives, or if paths is empty. Unlike commonprefix(), this returns a valid path.

Added in version 3.5.

버전 3.6에서 변경: 경로류 객체의 시퀀스를 받아들입니다.

버전 3.13에서 변경: Any iterable can now be passed, rather than just sequences.

os.path.commonprefix(list)

list에 있는 모든 경로의 접두사인 가장 긴 경로 접두사(문자 단위로 취합니다)를 반환합니다. list가 비어 있으면, 빈 문자열('')을 반환합니다.

참고

이 함수는 한 번에 한 문자씩 다루기 때문에 유효하지 않은 경로를 반환할 수 있습니다. 유효한 경로를 얻으려면, commonpath()를 참조하십시오.

>>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])
'/usr/l'

>>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])
'/usr'

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.dirname(path)

경로명 path의 디렉터리 이름을 반환합니다. 이것은 path를 함수 split()에 전달하여 반환된 쌍의 첫 번째 요소입니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.exists(path)

path가 기존 경로나 열린 파일 기술자를 참조하면 True를 반환합니다. 깨진 심볼릭 링크에 대해서는 False를 반환합니다. 일부 플랫폼에서, path가 물리적으로 존재하더라도, 요청된 파일에 대해 os.stat()을 실행할 권한이 없으면 이 함수는 False를 반환할 수 있습니다.

버전 3.3에서 변경: path는 이제 정수가 될 수 있습니다: 열린 파일 기술자이면 True가 반환되고, 그렇지 않으면 False가 반환됩니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.lexists(path)

Return True if path refers to an existing path, including broken symbolic links. Equivalent to exists() on platforms lacking os.lstat().

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.expanduser(path)

유닉스와 윈도우에서, ~나 ~user의 초기 구성 요소가 해당 사용자의 홈 디렉터리로 치환된 인자를 반환합니다.

유닉스에서, 초기 ~는 환경 변수 HOME이 설정되어 있다면 그것으로 치환됩니다; 그렇지 않으면 현재 사용자의 홈 디렉터리가 내장 모듈 pwd를 통해 비밀번호 디렉터리에서 조회됩니다. 초기 ~user는 비밀번호 디렉터리에서 직접 조회됩니다.

On Windows, USERPROFILE will be used if set, otherwise a combination of HOMEPATH and HOMEDRIVE will be used. An initial ~user is handled by checking that the last directory component of the current user’s home directory matches USERNAME, and replacing it if so.

확장이 실패하거나 경로가 물결표로 시작하지 않으면, 경로는 변경되지 않은 상태로 반환됩니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 더는 윈도우에서 HOME을 사용하지 않습니다.

os.path.expandvars(path)

환경 변수로 확장된 인자를 반환합니다. $name이나 ${name} 형식의 부분 문자열이 환경 변수 name의 값으로 치환됩니다. 잘못된 변수 이름과 존재하지 않는 변수에 대한 참조는 변경되지 않고 남습니다.

윈도우에서, $name과 ${name} 외에 %name% 확장이 지원됩니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.getatime(path)

Return the time of last access of path. The return value is a floating-point number giving the number of seconds since the epoch (see the time module). Raise OSError if the file does not exist or is inaccessible.

os.path.getmtime(path)

Return the time of last modification of path. The return value is a floating-point number giving the number of seconds since the epoch (see the time module). Raise OSError if the file does not exist or is inaccessible.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.getctime(path)

시스템의 ctime을 반환하는데, 일부 시스템(가령 유닉스)에서는 마지막 메타 데이터 변경 시간이고, 다른 시스템(가령 윈도우)에서는 path 생성 시간입니다. 반환 값은 에포크(epoch) 이후 초 수를 나타내는 부동 소수점 숫자입니다 (time 모듈을 참조하십시오). 파일이 없거나 액세스할 수 없으면 OSError를 발생시킵니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.getsize(path)

path의 크기를 바이트 단위로 반환합니다. 파일이 없거나 액세스할 수 없으면 OSError를 발생시킵니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.isabs(path)

Return True if path is an absolute pathname. On Unix, that means it begins with a slash, on Windows that it begins with two (back)slashes, or a drive letter, colon, and (back)slash together.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.13에서 변경: On Windows, returns False if the given path starts with exactly one (back)slash.

os.path.isfile(path)

path가 존재하는 일반 파일이면 True를 반환합니다. 이것은 심볼릭 링크를 따르므로, 같은 경로에 대해 islink()와 isfile()이 모두 참일 수 있습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.isdir(path)

path가 존재하는 디렉터리이면 True를 반환합니다. 이것은 심볼릭 링크를 따르므로, 같은 경로에 대해 islink()와 isdir()이 모두 참일 수 있습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.isjunction(path)

Return True if path refers to an existing directory entry that is a junction. Always return False if junctions are not supported on the current platform.

Added in version 3.12.

os.path.islink(path)

path가 심볼릭 링크인 존재하는 디렉터리 항목을 가리키면 True를 반환합니다. 파이썬 런타임에서 심볼릭 링크를 지원하지 않으면 항상 False입니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.ismount(path)

경로명 path가 마운트 지점(mount point)이면 True를 반환합니다: 다른 파일 시스템이 마운트된 파일 시스템의 지점. POSIX에서, 이 함수는 path의 부모 path/..가 path와 다른 장치에 있는지, 또는 path/..와 path가 같은 장치에서 같은 i-노드를 가리키는지를 확인합니다 — 이 방법은 모든 유닉스와 POSIX 변형에서 마운트 지점을 감지해야 합니다. 같은 파일 시스템에서의 바인드 마운트(bind mounts)를 신뢰성 있게 감지할 수 없습니다. 윈도우에서, 드라이브 문자 루트와 공유 UNC는 항상 마운트 지점이며, 다른 경로의 경우 GetVolumePathName을 호출해서 입력 경로와 다른지 봅니다.

버전 3.4에서 변경: Added support for detecting non-root mount points on Windows.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.isdevdrive(path)

Return True if pathname path is located on a Windows Dev Drive. A Dev Drive is optimized for developer scenarios, and offers faster performance for reading and writing files. It is recommended for use for source code, temporary build directories, package caches, and other IO-intensive operations.

May raise an error for an invalid path, for example, one without a recognizable drive, but returns False on platforms that do not support Dev Drives. See the Windows documentation [https://learn.microsoft.com/windows/dev-drive/] for information on enabling and creating Dev Drives.

Added in version 3.12.

버전 3.13에서 변경: The function is now available on all platforms, and will always return False on those that have no support for Dev Drives

os.path.isreserved(path)

Return True if path is a reserved pathname on the current system.

On Windows, reserved filenames include those that end with a space or dot; those that contain colons (i.e. file streams such as “name:stream”), wildcard characters (i.e. '*?"<>'), pipe, or ASCII control characters; as well as DOS device names such as “NUL”, “CON”, “CONIN$”, “CONOUT$”, “AUX”, “PRN”, “COM1”, and “LPT1”.

참고

This function approximates rules for reserved paths on most Windows systems. These rules change over time in various Windows releases. This function may be updated in future Python releases as changes to the rules become broadly available.

Availability: Windows.

Added in version 3.13.

os.path.join(path, *paths)

Join one or more path segments intelligently. The return value is the concatenation of path and all members of *paths, with exactly one directory separator following each non-empty part, except the last. That is, the result will only end in a separator if the last part is either empty or ends in a separator. If a segment is an absolute path (which on Windows requires both a drive and a root), then all previous segments are ignored and joining continues from the absolute path segment.

On Windows, the drive is not reset when a rooted path segment (e.g., r'\foo') is encountered. If a segment is on a different drive or is an absolute path, all previous segments are ignored and the drive is reset. Note that since there is a current directory for each drive, os.path.join("c:", "foo") represents a path relative to the current directory on drive C: (c:foo), not c:\foo.

버전 3.6에서 변경: path와 paths에 대해 경로류 객체를 받아들입니다.

os.path.normcase(path)

경로명의 대소 문자를 정규화합니다. 윈도우에서는, 경로명의 모든 문자를 소문자로 변환하고, 슬래시도 역 슬래시로 변환합니다. 다른 운영 체제에서는, 경로를 변경하지 않고 반환합니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.normpath(path)

중복된 구분자와 상위 수준 참조를 접어 경로명을 정규화합니다. 그래서 A//B, A/B/, A/./B 및 A/foo/../B가 모두 A/B가 됩니다. 이 문자열 조작은 심볼릭 링크가 포함된 경로의 의미를 변경할 수 있습니다. 윈도우에서는, 슬래시를 역 슬래시로 변환합니다. 대소 문자를 정규화하려면, normcase()를 사용하십시오.

참고

On POSIX systems, in accordance with IEEE Std 1003.1 2013 Edition; 4.13 Pathname Resolution [https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13], if a pathname begins with exactly two slashes, the first component following the leading characters may be interpreted in an implementation-defined manner, although more than two leading characters shall be treated as a single character.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.realpath(path, *, strict=False)

Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path (if they are supported by the operating system). On Windows, this function will also resolve MS-DOS (also called 8.3) style names such as C:\\PROGRA~1 to C:\\Program Files.

If a path doesn’t exist or a symlink loop is encountered, and strict is True, OSError is raised. If strict is False these errors are ignored, and so the result might be missing or otherwise inaccessible.

참고

This function emulates the operating system’s procedure for making a path canonical, which differs slightly between Windows and UNIX with respect to how links and subsequent path components interact.

Operating system APIs make paths canonical as needed, so it’s not normally necessary to call this function.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서 심볼릭 링크와 정션(junctions)이 이제 해석됩니다.

버전 3.10에서 변경: The strict parameter was added.

os.path.relpath(path, start=os.curdir)

Return a relative filepath to path either from the current directory or from an optional start directory. This is a path computation: the filesystem is not accessed to confirm the existence or nature of path or start. On Windows, ValueError is raised when path and start are on different drives.

start defaults to os.curdir.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.samefile(path1, path2)

두 경로명 인자가 같은 파일이나 디렉터리를 가리키면 True를 반환합니다. 장치 번호와 i-노드 번호로 결정하며 경로명 중 어느 하나에 대해 os.stat() 호출이 실패하면 예외를 발생시킵니다.

버전 3.2에서 변경: 윈도우 지원이 추가되었습니다.

버전 3.4에서 변경: 윈도우는 이제 다른 모든 플랫폼과 같은 구현을 사용합니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.sameopenfile(fp1, fp2)

파일 기술자 fp1과 fp2가 같은 파일을 가리키면 True를 반환합니다.

버전 3.2에서 변경: 윈도우 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.samestat(stat1, stat2)

stat 튜플 stat1과 stat2가 같은 파일을 가리키면 True를 반환합니다. 이러한 구조는 os.fstat(), os.lstat() 또는 os.stat()에 의해 반환되었을 수 있습니다. 이 함수는 samefile()과 sameopenfile()에서 사용하는 하부 비교를 구현합니다.

버전 3.4에서 변경: 윈도우 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.split(path)

path 경로명을 (head, tail) 쌍으로 분할합니다. 여기서 tail은 마지막 경로명 구성 요소이고 head는 그 앞에 오는 모든 것입니다. tail 부분에는 슬래시가 포함되지 않습니다; path가 슬래시로 끝나면, tail은 비어 있습니다. path에 슬래시가 없으면, head는 비어 있습니다. path가 비어 있으면, head와 tail이 모두 비어 있습니다. 후행 슬래시는 루트(하나나 그 이상의 슬래시로만 구성됩니다)가 아니라면 head에서 제거됩니다. 모든 경우에, join(head, tail)은 path와 같은 위치에 대한 경로를 반환합니다 (하지만 문자열은 다를 수 있습니다). dirname()과 basename() 함수도 참조하십시오.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.splitdrive(path)

경로명 path를 쌍 (drive, tail)로 분할합니다. 여기서 drive는 마운트 지점이나 빈 문자열입니다. 드라이브 지정을 사용하지 않는 시스템에서 drive는 항상 빈 문자열입니다. 모든 경우에, drive + tail은 path와 같습니다.

윈도우에서는, 경로명을 드라이브/UNC 공유 지점과 상대 경로로 분할합니다.

If the path contains a drive letter, drive will contain everything up to and including the colon:

>>> splitdrive("c:/dir")
("c:", "/dir")

If the path contains a UNC path, drive will contain the host name and share:

>>> splitdrive("//host/computer/dir")
("//host/computer", "/dir")

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.splitroot(path)

Split the pathname path into a 3-item tuple (drive, root, tail) where drive is a device name or mount point, root is a string of separators after the drive, and tail is everything after the root. Any of these items may be the empty string. In all cases, drive + root + tail will be the same as path.

On POSIX systems, drive is always empty. The root may be empty (if path is relative), a single forward slash (if path is absolute), or two forward slashes (implementation-defined per IEEE Std 1003.1-2017; 4.13 Pathname Resolution [https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13].) For example:

>>> splitroot('/home/sam')
('', '/', 'home/sam')
>>> splitroot('//home/sam')
('', '//', 'home/sam')
>>> splitroot('///home/sam')
('', '/', '//home/sam')

On Windows, drive may be empty, a drive-letter name, a UNC share, or a device name. The root may be empty, a forward slash, or a backward slash. For example:

>>> splitroot('C:/Users/Sam')
('C:', '/', 'Users/Sam')
>>> splitroot('//Server/Share/Users/Sam')
('//Server/Share', '/', 'Users/Sam')

Added in version 3.12.

os.path.splitext(path)

Split the pathname path into a pair (root, ext) such that root + ext == path, and the extension, ext, is empty or begins with a period and contains at most one period.

If the path contains no extension, ext will be '':

>>> splitext('bar')
('bar', '')

If the path contains an extension, then ext will be set to this extension, including the leading period. Note that previous periods will be ignored:

>>> splitext('foo.bar.exe')
('foo.bar', '.exe')
>>> splitext('/foo/bar.exe')
('/foo/bar', '.exe')

Leading periods of the last component of the path are considered to be part of the root:

>>> splitext('.cshrc')
('.cshrc', '')
>>> splitext('/foo/....jpg')
('/foo/....jpg', '')

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.path.supports_unicode_filenames

(파일 시스템에 의해 부과된 제한 내에서) 임의의 유니코드 문자열을 파일 이름으로 사용할 수 있으면 True.

fileinput — Iterate over lines from multiple input streams

소스 코드: Lib/fileinput.py [https://github.com/python/cpython/tree/main/Lib/fileinput.py]

이 모듈은 표준 입력이나 파일 목록에 대한 루프를 빠르게 작성하기 위한 도우미 클래스와 함수를 구현합니다. 단지 하나의 파일을 읽거나 쓰려면 open()을 참조하십시오.

일반적인 사용법은 다음과 같습니다:

import fileinput
for line in fileinput.input(encoding="utf-8"):
    process(line)

이것은 sys.argv[1:]에 나열된 모든 파일의 줄을 이터레이트 하며, 목록이 비어 있으면 기본값은 sys.stdin입니다. 파일 이름이 '-'이면, 이 또한 sys.stdin으로 대체되고 선택적 인자 mode와 openhook은 무시됩니다. 대체 파일명 목록을 지정하려면, input()의 첫 번째 인자로 전달하십시오. 단일 파일 이름도 허용됩니다.

모든 파일은 기본적으로 텍스트 모드로 열리지만, input()이나 FileInput을 호출할 때 mode 매개 변수를 지정하여 이를 재정의할 수 있습니다. 파일을 열거나 읽는 동안 I/O 에러가 발생하면, OSError가 발생합니다.

버전 3.3에서 변경: IOError가 발생했었습니다; 이제 이것은 OSError의 별칭입니다.

sys.stdin이 두 번 이상 사용되면, 대화식으로 사용되거나 명시적으로 재설정된 경우(예를 들어, sys.stdin.seek(0)을 사용해서)를 제외하고 두 번째와 그 이후의 사용은 줄을 반환하지 않습니다.

빈 파일은 열리고 즉시 닫힙니다; 파일명 목록에 존재함이 인식되는 유일한 시간은 마지막에 열린 파일이 비어있을 때입니다.

줄은 줄 바꿈이 그대로 유지된 채로 반환됩니다. 즉, 파일의 마지막 줄에는 줄 바꿈이 없을 수도 있습니다.

You can control how files are opened by providing an opening hook via the openhook parameter to fileinput.input() or FileInput(). The hook must be a function that takes two arguments, filename and mode, and returns an accordingly opened file-like object. If encoding and/or errors are specified, they will be passed to the hook as additional keyword arguments. This module provides a hook_compressed() to support compressed files.

다음 함수는 이 모듈의 기본 인터페이스입니다:

fileinput.input(files=None, inplace=False, backup='', *, mode='r', openhook=None, encoding=None, errors=None)

FileInput 클래스의 인스턴스를 만듭니다. 인스턴스는 이 모듈의 함수에 대한 전역 상태로 사용되며, 이터레이션 중에 사용하기 위해 반환되기도 합니다. 이 함수의 매개 변수는 FileInput 클래스의 생성자로 전달됩니다.

FileInput 인스턴스는 with 문에서 컨텍스트 관리자로 사용될 수 있습니다. 이 예제에서, 예외가 발생하더라도 with 문이 종료된 후 input이 닫힙니다:

with fileinput.input(files=('spam.txt', 'eggs.txt'), encoding="utf-8") as f:
    for line in f:
        process(line)

버전 3.2에서 변경: 컨텍스트 관리자로 사용할 수 있습니다.

버전 3.8에서 변경: 키워드 매개 변수 mode와 openhook은 이제 키워드 전용입니다.

버전 3.10에서 변경: The keyword-only parameter encoding and errors are added.

다음 함수는 fileinput.input()에 의해 만들어진 전역 상태를 사용합니다; 활성 상태가 없으면, RuntimeError가 발생합니다.

fileinput.filename()

현재 읽고 있는 파일의 이름을 반환합니다. 첫 번째 줄을 읽기 전에는, None을 반환합니다.

fileinput.fileno()

현재 파일의 정수 “파일 기술자”를 반환합니다. 파일이 열리지 않았으면 (첫 번째 줄 전과 파일 사이에), -1을 반환합니다.

fileinput.lineno()

방금 읽은 줄의 누적 줄 번호를 반환합니다. 첫 번째 줄을 읽기 전에는, 0을 반환합니다. 마지막 파일의 마지막 줄을 읽은 후에는, 그 줄의 줄 번호를 반환합니다.

fileinput.filelineno()

현재 파일의 줄 번호를 반환합니다. 첫 번째 줄을 읽기 전에는, 0을 반환합니다. 마지막 파일의 마지막 줄을 읽은 후에는, 그 줄의 파일 내에서의 줄 번호를 반환합니다.

fileinput.isfirstline()

방금 읽은 줄이 파일의 첫 번째 줄이면 True를, 그렇지 않으면 False를 반환합니다.

fileinput.isstdin()

마지막 줄을 sys.stdin에서 읽었으면 True를, 그렇지 않으면 False를 반환합니다.

fileinput.nextfile()

다음 이터레이션에서 다음 파일(있다면)의 첫 번째 줄을 읽도록 현재 파일을 닫습니다; 파일에서 읽지 않은 줄은 누적 줄 수에 포함되지 않습니다. 파일명은 다음 파일의 첫 번째 줄을 읽을 때까지 변경되지 않습니다. 첫 번째 줄을 읽기 전에는, 이 함수가 효과가 없습니다; 첫 번째 파일을 건너뛰는 데 사용할 수 없습니다. 마지막 파일의 마지막 줄을 읽은 후에는, 이 함수는 효과가 없습니다.

fileinput.close()

시퀀스를 닫습니다.

모듈이 제공하는 시퀀스 동작을 구현하는 클래스는 서브 클래싱에도 사용할 수 있습니다:

class fileinput.FileInput(files=None, inplace=False, backup='', *, mode='r', openhook=None, encoding=None, errors=None)

Class FileInput is the implementation; its methods filename(), fileno(), lineno(), filelineno(), isfirstline(), isstdin(), nextfile() and close() correspond to the functions of the same name in the module. In addition it is iterable and has a readline() method which returns the next input line. The sequence must be accessed in strictly sequential order; random access and readline() cannot be mixed.

With mode you can specify which file mode will be passed to open(). It must be one of 'r' and 'rb'.

openhook이 제공되면 두 개의 인자 filename과 mode를 취하고, 이에 따라 열린 파일류 객체를 반환하는 함수여야 합니다. inplace와 openhook을 함께 사용할 수 없습니다.

You can specify encoding and errors that is passed to open() or openhook.

FileInput 인스턴스는 with 문에서 컨텍스트 관리자로 사용될 수 있습니다. 이 예제에서, 예외가 발생하더라도 with 문이 종료된 후 input이 닫힙니다:

with FileInput(files=('spam.txt', 'eggs.txt')) as input:
    process(input)

버전 3.2에서 변경: 컨텍스트 관리자로 사용할 수 있습니다.

버전 3.8에서 변경: 키워드 매개 변수 mode와 openhook은 이제 키워드 전용입니다.

버전 3.10에서 변경: The keyword-only parameter encoding and errors are added.

버전 3.11에서 변경: The 'rU' and 'U' modes and the __getitem__() method have been removed.

선택적 제자리 필터링(in-place filtering): 키워드 인자 inplace=True가 fileinput.input()이나 FileInput 생성자로 전달되면, 파일이 백업 파일로 이동되고 표준 출력은 입력 파일로 보내집니다 (백업 파일과 같은 이름의 파일이 이미 있으면, 조용히 대체됩니다). 이를 통해 입력 파일을 다시 쓰는 필터를 작성할 수 있습니다. backup 매개 변수가 제공되면 (일반적으로 backup='.<some extension>'으로), 백업 파일의 확장자를 지정하고, 백업 파일은 그대로 남아 있습니다; 기본적으로 확장자는 '.bak'이고, 출력 파일을 닫을 때 삭제됩니다. 표준 입력을 읽을 때는 제자리 필터링이 비활성화됩니다.

이 모듈은 다음과 같은 두 개의 열기 훅을 제공합니다:

fileinput.hook_compressed(filename, mode, *, encoding=None, errors=None)

gzip과 bz2 모듈을 사용하여 gzip과 bzip2로 압축된 파일(확장자 '.gz'와 '.bz2'로 인식합니다)을 투명하게 엽니다. 파일명 확장자가 '.gz'나 '.bz2'가 아니면, 파일이 정상적으로 열립니다 (즉, 압축 해제 없이 open()을 사용합니다).

The encoding and errors values are passed to io.TextIOWrapper for compressed files and open for normal files.

Usage example: fi = fileinput.FileInput(openhook=fileinput.hook_compressed, encoding="utf-8")

버전 3.10에서 변경: The keyword-only parameter encoding and errors are added.

fileinput.hook_encoded(encoding, errors=None)

주어진 encoding과 errors를 사용하여 파일을 읽도록 open()으로 각 파일을 여는 훅을 반환합니다.

사용 예: fi = fileinput.FileInput(openhook=fileinput.hook_encoded("utf-8", "surrogateescape"))

버전 3.6에서 변경: 선택적 errors 매개 변수를 추가했습니다.

버전 3.10부터 폐지됨: This function is deprecated since fileinput.input() and FileInput now have encoding and errors parameters.

stat — Interpreting stat() results

소스 코드: Lib/stat.py [https://github.com/python/cpython/tree/main/Lib/stat.py]

The stat module defines constants and functions for interpreting the results of os.stat(), os.fstat() and os.lstat() (if they exist). For complete details about the stat(), fstat() and lstat() calls, consult the documentation for your system.

버전 3.4에서 변경: stat 모듈은 C 구현으로 지원됩니다.

stat 모듈은 특정 파일 유형을 검사하기 위해 다음 함수를 정의합니다:

stat.S_ISDIR(mode)

mode가 디렉터리로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISCHR(mode)

mode가 문자 특수 장치(character special device) 파일로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISBLK(mode)

mode가 블록 특수 장치(block special device) 파일로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISREG(mode)

mode가 일반 파일로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISFIFO(mode)

mode가 FIFO(네임드 파이프)로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISLNK(mode)

mode가 심볼릭 링크로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISSOCK(mode)

mode가 소켓으로부터 왔으면 0이 아닌 값을 반환합니다.

stat.S_ISDOOR(mode)

mode가 door로부터 왔으면 0이 아닌 값을 반환합니다.

Added in version 3.4.

stat.S_ISPORT(mode)

mode가 이벤트 포트(event port)로부터 왔으면 0이 아닌 값을 반환합니다.

Added in version 3.4.

stat.S_ISWHT(mode)

mode가 화이트 아웃(whiteout)으로부터 왔으면 0이 아닌 값을 반환합니다.

Added in version 3.4.

파일의 모드(mode)를 보다 일반적으로 조작하기 위한 두 가지 추가 함수가 정의됩니다:

stat.S_IMODE(mode)

os.chmod()로 설정할 수 있는 파일 모드 부분을 반환합니다 —즉, 파일의 권한(permission) 비트, 끈끈한(sticky) 비트, set-group-id 및 set-user-id 비트 (지원하는 시스템에서).

stat.S_IFMT(mode)

Return the portion of the file’s mode that describes the file type (used by the S_IS*() functions above).

Normally, you would use the os.path.is*() functions for testing the type of a file; the functions here are useful when you are doing multiple tests of the same file and wish to avoid the overhead of the stat() system call for each test. These are also useful when checking for information about a file that isn’t handled by os.path, like the tests for block and character devices.

예제:

import os, sys
from stat import *

def walktree(top, callback):
    '''recursively descend the directory tree rooted at top,
       calling the callback function for each regular file'''

    for f in os.listdir(top):
        pathname = os.path.join(top, f)
        mode = os.lstat(pathname).st_mode
        if S_ISDIR(mode):
            # It's a directory, recurse into it
            walktree(pathname, callback)
        elif S_ISREG(mode):
            # It's a file, call the callback function
            callback(pathname)
        else:
            # Unknown file type, print a message
            print('Skipping %s' % pathname)

def visitfile(file):
    print('visiting', file)

if __name__ == '__main__':
    walktree(sys.argv[1], visitfile)

파일의 모드를 사람이 읽을 수 있는 문자열로 변환하기 위한 추가 유틸리티 함수가 제공됩니다:

stat.filemode(mode)

파일의 mode를 ‘-rwxrwxrwx’ 형식의 문자열로 변환합니다.

Added in version 3.3.

버전 3.4에서 변경: 이 함수는 S_IFDOOR, S_IFPORT 및 S_IFWHT를 지원합니다.

아래의 모든 변수는 단순히 os.stat(), os.fstat() 또는 os.lstat()에 의해 반환된 10-튜플에 대한 기호 인덱스입니다.

stat.ST_MODE

아이 노드(inode) 보호 모드.

stat.ST_INO

아이 노드(inode) 번호.

stat.ST_DEV

아이 노드(inode)가 위치한 장치.

stat.ST_NLINK

아이 노드(inode)에 대한 링크 수.

stat.ST_UID

소유자의 사용자 id.

stat.ST_GID

소유자의 그룹 id.

stat.ST_SIZE

일반 파일의 크기(바이트); 일부 특수 파일에서는 대기중인 데이터의 양.

stat.ST_ATIME

마지막 액세스 시간.

stat.ST_MTIME

마지막 수정 시간.

stat.ST_CTIME

운영 체제에서 보고한 “ctime”. (유닉스와 같은) 일부 시스템에서는 마지막 메타 데이터 변경 시간이고, (윈도우와 같은) 다른 시스템에서는 생성 시간입니다 (자세한 내용은 플랫폼 설명서를 참조하십시오).

“파일 크기”의 해석은 파일 유형에 따라 달라집니다. 일반 파일에서는 바이트로 표현한 파일의 크기입니다. 대부분의 유닉스(특히 리눅스를 포함하는)의 FIFO와 소켓에서, “크기”는 os.stat(), os.fstat() 또는 os.lstat()를 호출한 시점에 읽기 대기 중인 바이트 수입니다; 이것은 때때로, 특히 비 블로킹으로 연 후에 이러한 특수 파일 중 하나를 폴링할 때 유용할 수 있습니다. 다른 문자와 블록 장치에서 크기 필드의 의미는 하부 시스템 호출의 구현에 따라 더 다양합니다.

아래의 변수는 ST_MODE 필드에서 사용되는 플래그를 정의합니다.

첫 번째 플래그 집합을 사용하는 것보다 위의 함수를 사용하는 것이 더 이식성 있습니다:

stat.S_IFSOCK

소켓.

stat.S_IFLNK

심볼릭 링크.

stat.S_IFREG

일반 파일.

stat.S_IFBLK

블록 장치.

stat.S_IFDIR

디렉터리.

stat.S_IFCHR

문자 장치.

stat.S_IFIFO

FIFO.

stat.S_IFDOOR

Door.

Added in version 3.4.

stat.S_IFPORT

이벤트 포트.

Added in version 3.4.

stat.S_IFWHT

화이트 아웃(whiteout).

Added in version 3.4.

참고

플랫폼이 파일 유형을 지원하지 않으면, S_IFDOOR, S_IFPORT 또는 S_IFWHT는 0으로 정의됩니다.

다음 플래그는 os.chmod()의 mode 인자에서도 사용할 수 있습니다:

stat.S_ISUID

Set-user-ID 비트.

stat.S_ISGID

Set-group-ID 비트. 이 비트는 몇 가지 특별한 용도로 사용됩니다. 디렉터리에서는 그 디렉터리가 BSD의 의미가 있음을 나타냅니다: 여기에 만들어진 파일은 만드는 프로세스의 유효 그룹 ID가 아니라 디렉터리에서 그룹 ID를 상속받고, S_ISGID 비트 설정도 얻습니다. 그룹 실행 비트(S_IXGRP)가 설정되지 않은 파일의 경우, set-group-ID 비트는 필수 파일/레코드 잠금을 나타냅니다 (S_ENFMT도 참조하십시오).

stat.S_ISVTX

끈끈한(sticky) 비트. 이 비트가 디렉터리에 설정되면, 해당 디렉터리의 파일은 파일의 소유자, 디렉터리의 소유자 또는 권한 있는(privileged) 프로세스에 의해서만 이름이 바뀌거나 삭제될 수 있음을 의미합니다.

stat.S_IRWXU

파일 소유자 권한(permission) 마스크.

stat.S_IRUSR

소유자에게 읽기 권한이 있습니다.

stat.S_IWUSR

소유자에게 쓰기 권한이 있습니다.

stat.S_IXUSR

소유자에게 실행 권한이 있습니다.

stat.S_IRWXG

그룹 권한 마스크.

stat.S_IRGRP

그룹에 읽기 권한이 있습니다.

stat.S_IWGRP

그룹에 쓰기 권한이 있습니다.

stat.S_IXGRP

그룹에 실행 권한이 있습니다.

stat.S_IRWXO

다른 사용자(그룹에 없는)에 대한 권한 마스크.

stat.S_IROTH

다른 사용자에게 읽기 권한이 있습니다.

stat.S_IWOTH

다른 사용자에게 쓰기 권한이 있습니다.

stat.S_IXOTH

다른 사용자에게 실행 권한이 있습니다.

stat.S_ENFMT

System V 파일 잠금 강제. 이 플래그는 S_ISGID와 공유됩니다: 파일/레코드 잠금이 그룹 실행 비트(S_IXGRP)가 설정되지 않은 파일에 적용됩니다.

stat.S_IREAD

S_IRUSR에 대한 유닉스 V7 동의어.

stat.S_IWRITE

S_IWUSR에 대한 유닉스 V7 동의어.

stat.S_IEXEC

S_IXUSR에 대한 유닉스 V7 동의어.

다음 플래그는 os.chflags()의 flags 인자에서 사용될 수 있습니다:

stat.UF_SETTABLE

All user settable flags.

Added in version 3.13.

stat.UF_NODUMP

파일을 덤프하지 마십시오.

stat.UF_IMMUTABLE

파일을 변경할 수 없습니다.

stat.UF_APPEND

파일은 덧붙이기만 할 수 있습니다.

stat.UF_OPAQUE

디렉터리는 유니언 스택(union stack)을 통해 볼 때 불투명합니다.

stat.UF_NOUNLINK

파일의 이름을 변경하거나 삭제할 수 없습니다.

stat.UF_COMPRESSED

The file is stored compressed (macOS 10.6+).

stat.UF_TRACKED

Used for handling document IDs (macOS)

Added in version 3.13.

stat.UF_DATAVAULT

The file needs an entitlement for reading or writing (macOS 10.13+)

Added in version 3.13.

stat.UF_HIDDEN

The file should not be displayed in a GUI (macOS 10.5+).

stat.SF_SETTABLE

All super-user changeable flags

Added in version 3.13.

stat.SF_SUPPORTED

All super-user supported flags

Availability: macOS

Added in version 3.13.

stat.SF_SYNTHETIC

All super-user read-only synthetic flags

Availability: macOS

Added in version 3.13.

stat.SF_ARCHIVED

파일을 보관(archive)할 수 있습니다.

stat.SF_IMMUTABLE

파일을 변경할 수 없습니다.

stat.SF_APPEND

파일은 덧붙이기만 할 수 있습니다.

stat.SF_RESTRICTED

The file needs an entitlement to write to (macOS 10.13+)

Added in version 3.13.

stat.SF_NOUNLINK

파일의 이름을 변경하거나 삭제할 수 없습니다.

stat.SF_SNAPSHOT

파일은 스냅숏(snapshot) 파일입니다.

stat.SF_FIRMLINK

The file is a firmlink (macOS 10.15+)

Added in version 3.13.

stat.SF_DATALESS

The file is a dataless object (macOS 10.15+)

Added in version 3.13.

See the *BSD or macOS systems man page chflags(2) [https://manpages.debian.org/chflags(2)] for more information.

윈도우에서 os.stat()에 의해 반환된 st_file_attributes 멤버의 비트를 검사할 때 다음 파일 어트리뷰트 상수를 사용할 수 있습니다. 이러한 상수의 의미에 대한 자세한 내용은 Windows API documentation [https://msdn.microsoft.com/en-us/library/windows/desktop/gg258117.aspx]을 참조하십시오.

stat.FILE_ATTRIBUTE_ARCHIVE

stat.FILE_ATTRIBUTE_COMPRESSED

stat.FILE_ATTRIBUTE_DEVICE

stat.FILE_ATTRIBUTE_DIRECTORY

stat.FILE_ATTRIBUTE_ENCRYPTED

stat.FILE_ATTRIBUTE_HIDDEN

stat.FILE_ATTRIBUTE_INTEGRITY_STREAM

stat.FILE_ATTRIBUTE_NORMAL

stat.FILE_ATTRIBUTE_NOT_CONTENT_INDEXED

stat.FILE_ATTRIBUTE_NO_SCRUB_DATA

stat.FILE_ATTRIBUTE_OFFLINE

stat.FILE_ATTRIBUTE_READONLY

stat.FILE_ATTRIBUTE_REPARSE_POINT

stat.FILE_ATTRIBUTE_SPARSE_FILE

stat.FILE_ATTRIBUTE_SYSTEM

stat.FILE_ATTRIBUTE_TEMPORARY

stat.FILE_ATTRIBUTE_VIRTUAL

Added in version 3.5.

윈도우에서, os.lstat()이 반환한 st_reparse_tag 멤버와 비교하기 위해 다음 상수를 사용할 수 있습니다. 이것들은 잘 알려진 상수이지만, 완전한 목록은 아닙니다.

stat.IO_REPARSE_TAG_SYMLINK

stat.IO_REPARSE_TAG_MOUNT_POINT

stat.IO_REPARSE_TAG_APPEXECLINK

Added in version 3.8.

filecmp — File and Directory Comparisons

소스 코드: Lib/filecmp.py [https://github.com/python/cpython/tree/main/Lib/filecmp.py]

filecmp 모듈은 다양한 선택적 시간/정확도 절충을 통해 파일과 디렉터리를 비교하는 함수를 정의합니다. 파일 비교에 대해서는, difflib 모듈을 참조하십시오.

filecmp 모듈은 다음 함수를 정의합니다:

filecmp.cmp(f1, f2, shallow=True)

f1와 f2로 이름이 지정된 파일을 비교하여, 같아 보이면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

If shallow is true and the os.stat() signatures (file type, size, and modification time) of both files are identical, the files are taken to be equal.

Otherwise, the files are treated as different if their sizes or contents differ.

이 함수는 외부 프로그램을 호출하지 않으므로 이식성과 효율성을 제공합니다.

이 함수는 과거 비교와 결과에 대해 캐시를 사용합니다. 파일에 대한 os.stat() 정보가 변경되면 캐시 항목이 무효화 됩니다. 전체 캐시는 clear_cache()를 사용하여 지울 수 있습니다.

filecmp.cmpfiles(dir1, dir2, common, shallow=True)

두 디렉터리 dir1 과 dir2에 있는 이름이 common으로 지정된 파일들을 비교합니다.

파일 이름의 세 가지 리스트를 반환합니다: match, mismatch, errors. match는 일치하는 파일 리스트를 포함하고, mismatch는 일치하지 않는 파일의 이름을 포함하며, errors는 비교할 수 없는 파일의 이름을 나열합니다. 파일이 디렉터리 중 하나에 없거나, 사용자가 읽을 수 있는 권한이 없거나, 다른 이유로 인해 비교를 수행할 수 없으면 파일은 errors에 나열됩니다.

shallow 매개 변수는 filecmp.cmp()와 같은 의미와 기본값을 가집니다.

예를 들어, cmpfiles('a', 'b', ['c', 'd/e'])는 a/c와 b/c, a/d/e와 b/d/e를 비교합니다. 'c' 와 'd/e'는 각각 반환된 세 개의 리스트 중 하나에 포함됩니다.

filecmp.clear_cache()

filecmp 캐시를 지웁니다. 파일이 수정된 후 너무 빨리 비교되어 하부 파일 시스템의 mtime 해상도 내에 있을 때 유용합니다.

Added in version 3.4.

dircmp 클래스

class filecmp.dircmp(a, b, ignore=None, hide=None, *, shallow=True)

Construct a new directory comparison object, to compare the directories a and b. ignore is a list of names to ignore, and defaults to filecmp.DEFAULT_IGNORES. hide is a list of names to hide, and defaults to [os.curdir, os.pardir].

The dircmp class compares files by doing shallow comparisons as described for filecmp.cmp() by default using the shallow parameter.

버전 3.13에서 변경: Added the shallow parameter.

dircmp 클래스는 다음 메서드를 제공합니다:

report()

a와 b 사이의 비교를 (sys.stdout로) 인쇄합니다.

report_partial_closure()

a와 b 및 공통 직접 하위 디렉터리 사이의 비교를 인쇄합니다.

report_full_closure()

a와 b 및 공통 하위 디렉터리 (재귀적으로) 사이의 비교를 인쇄합니다.

dircmp 클래스는 비교되는 디렉터리 트리에 대한 다양한 정보 비트를 얻는 데 사용될 수 있는 여러 가지 흥미로운 어트리뷰트를 제공합니다.

Note that via __getattr__() hooks, all attributes are computed lazily, so there is no speed penalty if only those attributes which are lightweight to compute are used.

left

디렉터리 a.

right

디렉터리 b.

left_list

hide 와 ignore로 필터링 된, a의 파일과 하위 디렉터리.

right_list

hide 와 ignore로 필터링 된, b의 파일과 하위 디렉터리.

common

a 와 b의 공통 파일과 하위 디렉터리.

left_only

a에만 있는 파일과 하위 디렉터리.

right_only

b에만 있는 파일과 하위 디렉터리.

common_dirs

a 및 b의 공통 하위 디렉터리.

common_files

a 와 b의 공통 파일.

common_funny

a와 b의 공통 이름으로, 디렉터리 간에 유형이 다르거나, os.stat()가 에러를 보고하는 이름.

same_files

a 와 b에 모두 있고, 클래스의 파일 비교 연산자를 사용할 때 같은 파일.

diff_files

a 및 b에 모두 있고, 클래스의 파일 비교 연산자를 사용할 때 내용이 다른 파일.

funny_files

a 및 b에 모두 있지만, 비교할 수 없는 파일.

subdirs

A dictionary mapping names in common_dirs to dircmp instances (or MyDirCmp instances if this instance is of type MyDirCmp, a subclass of dircmp).

버전 3.10에서 변경: Previously entries were always dircmp instances. Now entries are the same type as self, if self is a subclass of dircmp.

filecmp.DEFAULT_IGNORES

Added in version 3.4.

dircmp에 의해 기본적으로 무시되는 디렉터리 리스트.

다음은 이름이 같지만, 내용이 다른 파일을 표시하기 위해, subdirs 어트리뷰트로 두 개의 디렉터리를 재귀적으로 검색하는 간단한 예제입니다:

>>> from filecmp import dircmp
>>> def print_diff_files(dcmp):
...     for name in dcmp.diff_files:
...         print("diff_file %s found in %s and %s" % (name, dcmp.left,
...               dcmp.right))
...     for sub_dcmp in dcmp.subdirs.values():
...         print_diff_files(sub_dcmp)
...
>>> dcmp = dircmp('dir1', 'dir2')
>>> print_diff_files(dcmp)

tempfile — Generate temporary files and directories

소스 코드: Lib/tempfile.py [https://github.com/python/cpython/tree/main/Lib/tempfile.py]

This module creates temporary files and directories. It works on all supported platforms. TemporaryFile, NamedTemporaryFile, TemporaryDirectory, and SpooledTemporaryFile are high-level interfaces which provide automatic cleanup and can be used as context managers. mkstemp() and mkdtemp() are lower-level functions which require manual cleanup.

사용자가 호출할 수 있는 모든 함수와 생성자는 임시 파일과 디렉터리의 위치와 이름을 직접 제어할 수 있도록 하는 추가 인자를 취합니다. 이 모듈에서 사용하는 파일 이름에는 무작위 문자의 문자열이 포함되어있어 공유 임시 디렉터리에서 해당 파일을 안전하게 만들 수 있도록 합니다. 이전 버전과의 호환성을 유지하기 위해, 인자 순서는 다소 이상합니다; 명확성을 위해 키워드 인자를 사용하는 것이 좋습니다.

이 모듈은 다음과 같은 사용자 호출 가능 항목을 정의합니다:

tempfile.TemporaryFile(mode='w+b', buffering=-1, encoding=None, newline=None, suffix=None, prefix=None, dir=None, *, errors=None)

임시 저장 영역으로 사용할 수 있는 파일류 객체를 반환합니다. mkstemp()와 같은 규칙을 사용하여 파일이 안전하게 만들어집니다. 닫히는 즉시 삭제됩니다 (객체가 가비지 수집될 때 묵시적인 닫기를 포함합니다). 유닉스에서, 파일의 디렉터리 항목은 전혀 만들어지지 않거나 파일이 만들어진 직후에 제거됩니다. 다른 플랫폼은 이를 지원하지 않습니다; 코드는 이 함수를 사용하여 만들어진 임시 파일이 파일 시스템에서 보이는 이름이 있거나 없는지에 의존해서는 안 됩니다.

The resulting object can be used as a context manager (see 예). On completion of the context or destruction of the file object the temporary file will be removed from the filesystem.

mode 매개 변수는 기본적으로 'w+b'로 설정되므로 만들어진 파일을 닫지 않고 읽고 쓸 수 있습니다. 저장된 데이터와 관계없이 모든 플랫폼에서 일관되게 작동하도록 바이너리 모드가 사용됩니다. buffering, encoding, errors 및 newline은 open()처럼 해석됩니다.

dir, prefix 및 suffix 매개 변수는 mkstemp()와 같은 의미와 기본값을 갖습니다.

반환된 객체는 POSIX 플랫폼에서 실제 파일 객체입니다. 다른 플랫폼에서는, file 어트리뷰트가 하부 실제 파일 객체인 파일류 객체입니다.

The os.O_TMPFILE flag is used if it is available and works (Linux-specific, requires Linux kernel 3.11 or later).

On platforms that are neither Posix nor Cygwin, TemporaryFile is an alias for NamedTemporaryFile.

인자 fullpath로 감사 이벤트 tempfile.mkstemp를 발생시킵니다.

버전 3.5에서 변경: The os.O_TMPFILE flag is now used if available.

버전 3.8에서 변경: errors 매개 변수를 추가했습니다.

tempfile.NamedTemporaryFile(mode='w+b', buffering=-1, encoding=None, newline=None, suffix=None, prefix=None, dir=None, delete=True, *, errors=None, delete_on_close=True)

This function operates exactly as TemporaryFile() does, except the following differences:

This function returns a file that is guaranteed to have a visible name in the file system.

To manage the named file, it extends the parameters of TemporaryFile() with delete and delete_on_close parameters that determine whether and how the named file should be automatically deleted.

The returned object is always a file-like object whose file attribute is the underlying true file object. This file-like object can be used in a with statement, just like a normal file. The name of the temporary file can be retrieved from the name attribute of the returned file-like object. On Unix, unlike with the TemporaryFile(), the directory entry does not get unlinked immediately after the file creation.

If delete is true (the default) and delete_on_close is true (the default), the file is deleted as soon as it is closed. If delete is true and delete_on_close is false, the file is deleted on context manager exit only, or else when the file-like object is finalized. Deletion is not always guaranteed in this case (see object.__del__()). If delete is false, the value of delete_on_close is ignored.

Therefore to use the name of the temporary file to reopen the file after closing it, either make sure not to delete the file upon closure (set the delete parameter to be false) or, in case the temporary file is created in a with statement, set the delete_on_close parameter to be false. The latter approach is recommended as it provides assistance in automatic cleaning of the temporary file upon the context manager exit.

Opening the temporary file again by its name while it is still open works as follows:

On POSIX the file can always be opened again.

On Windows, make sure that at least one of the following conditions are fulfilled:

delete is false

additional open shares delete access (e.g. by calling os.open() with the flag O_TEMPORARY)

delete is true but delete_on_close is false. Note, that in this case the additional opens that do not share delete access (e.g. created via builtin open()) must be closed before exiting the context manager, else the os.unlink() call on context manager exit will fail with a PermissionError.

On Windows, if delete_on_close is false, and the file is created in a directory for which the user lacks delete access, then the os.unlink() call on exit of the context manager will fail with a PermissionError. This cannot happen when delete_on_close is true because delete access is requested by the open, which fails immediately if the requested access is not granted.

On POSIX (only), a process that is terminated abruptly with SIGKILL cannot automatically delete any NamedTemporaryFiles it created.

인자 fullpath로 감사 이벤트 tempfile.mkstemp를 발생시킵니다.

버전 3.8에서 변경: errors 매개 변수를 추가했습니다.

버전 3.12에서 변경: Added delete_on_close parameter.

class tempfile.SpooledTemporaryFile(max_size=0, mode='w+b', buffering=-1, encoding=None, newline=None, suffix=None, prefix=None, dir=None, *, errors=None)

This class operates exactly as TemporaryFile() does, except that data is spooled in memory until the file size exceeds max_size, or until the file’s fileno() method is called, at which point the contents are written to disk and operation proceeds as with TemporaryFile().

rollover()

The resulting file has one additional method, rollover(), which causes the file to roll over to an on-disk file regardless of its size.

The returned object is a file-like object whose _file attribute is either an io.BytesIO or io.TextIOWrapper object (depending on whether binary or text mode was specified) or a true file object, depending on whether rollover() has been called. This file-like object can be used in a with statement, just like a normal file.

버전 3.3에서 변경: the truncate method now accepts a size argument.

버전 3.8에서 변경: errors 매개 변수를 추가했습니다.

버전 3.11에서 변경: Fully implements the io.BufferedIOBase and io.TextIOBase abstract base classes (depending on whether binary or text mode was specified).

class tempfile.TemporaryDirectory(suffix=None, prefix=None, dir=None, ignore_cleanup_errors=False, *, delete=True)

This class securely creates a temporary directory using the same rules as mkdtemp(). The resulting object can be used as a context manager (see 예). On completion of the context or destruction of the temporary directory object, the newly created temporary directory and all its contents are removed from the filesystem.

name

The directory name can be retrieved from the name attribute of the returned object. When the returned object is used as a context manager, the name will be assigned to the target of the as clause in the with statement, if there is one.

cleanup()

The directory can be explicitly cleaned up by calling the cleanup() method. If ignore_cleanup_errors is true, any unhandled exceptions during explicit or implicit cleanup (such as a PermissionError removing open files on Windows) will be ignored, and the remaining removable items deleted on a “best-effort” basis. Otherwise, errors will be raised in whatever context cleanup occurs (the cleanup() call, exiting the context manager, when the object is garbage-collected or during interpreter shutdown).

The delete parameter can be used to disable cleanup of the directory tree upon exiting the context. While it may seem unusual for a context manager to disable the action taken when exiting the context, it can be useful during debugging or when you need your cleanup behavior to be conditional based on other logic.

인자 fullpath로 감사 이벤트 tempfile.mkdtemp를 발생시킵니다.

Added in version 3.2.

버전 3.10에서 변경: Added ignore_cleanup_errors parameter.

버전 3.12에서 변경: Added the delete parameter.

tempfile.mkstemp(suffix=None, prefix=None, dir=None, text=False)

가장 안전한 방식으로 임시 파일을 만듭니다. 플랫폼이 os.open()에서 os.O_EXCL 플래그를 올바르게 구현한다고 가정할 때, 파일 생성에 경쟁 조건이 없습니다. 파일은 만드는 사용자 ID만 읽고 쓸 수 있습니다. 플랫폼이 권한 비트를 사용하여 파일이 실행 가능한지를 나타내면, 파일은 아무도 실행할 수 없습니다. 파일 기술자는 자식 프로세스에 의해 상속되지 않습니다.

TemporaryFile()과 달리, mkstemp()의 사용자는 임시 파일로의 작업을 끝내면 파일을 삭제해야 합니다.

suffix가 None이 아니면, 파일 이름은 해당 접미사로 끝납니다, 그렇지 않으면 접미사가 없습니다. mkstemp()는 파일 이름과 접미사 사이에 점을 넣지 않습니다; 필요하면 suffix의 시작 부분에 넣으십시오.

prefix가 None이 아니면, 파일 이름은 해당 접두사로 시작합니다; 그렇지 않으면 기본 접두사가 사용됩니다. 기본값은 gettempprefix()나 gettempprefixb() 중 적절한 것의 반환 값입니다.

dir이 None이 아니면, 파일은 해당 디렉터리에 만들어집니다; 그렇지 않으면 기본 디렉터리가 사용됩니다. 기본 디렉터리는 플랫폼별 목록에서 선택되지만, 응용 프로그램 사용자는 TMPDIR, TEMP 또는 TMP 환경 변수를 설정하여 디렉터리 위치를 제어할 수 있습니다. 따라서 생성된 파일명이 os.popen()을 통해 외부 명령에 전달될 때 따옴표 처리할 필요가 없는 것과 같은 멋진 속성을 가질 것이라는 보장은 없습니다.

suffix, prefix 및 dir 중 어느 것이라도 None이 아니면, 그들은 같은 형이어야 합니다. 이들이 바이트열이면, 반환되는 이름은 str 대신 바이트열입니다. 기본 동작으로 바이트열 반환 값을 강제하려면 suffix=b''를 전달하십시오.

text가 지정되고 참이면, 파일은 텍스트 모드로 열립니다. 그렇지 않으면 (기본값) 파일은 바이너리 모드로 열립니다.

mkstemp()는 열린 파일에 대한 OS 수준 핸들(os.open()에서 반환하는 것)과 해당 파일의 절대 경로를 이 순서대로 포함하는 튜플을 반환합니다.

인자 fullpath로 감사 이벤트 tempfile.mkstemp를 발생시킵니다.

버전 3.5에서 변경: 바이트열 반환 값을 얻기 위해 suffix, prefix 및 dir를 이제 바이트열로 제공할 수 있습니다. 이전에는, str만 허용되었습니다. suffix와 prefix는 이제 기본값이 None이고 적절한 기본값이 사용되도록 합니다.

버전 3.6에서 변경: dir 매개 변수는 이제 경로류 객체를 받아들입니다.

tempfile.mkdtemp(suffix=None, prefix=None, dir=None)

가장 안전한 방식으로 임시 디렉터리를 만듭니다. 디렉터리 생성에 경쟁 조건이 없습니다. 디렉터리는 만드는 사용자 ID만 읽고 쓰고 검색할 수 있습니다.

mkdtemp()의 사용자는 임시 디렉터리로의 작업을 끝내면 임시 디렉터리와 디렉터리의 내용을 삭제해야 합니다.

prefix, suffix 및 dir 인자는 mkstemp()와 같습니다.

mkdtemp()는 새 디렉터리의 절대 경로명을 반환합니다.

인자 fullpath로 감사 이벤트 tempfile.mkdtemp를 발생시킵니다.

버전 3.5에서 변경: 바이트열 반환 값을 얻기 위해 suffix, prefix 및 dir를 이제 바이트열로 제공할 수 있습니다. 이전에는, str만 허용되었습니다. suffix와 prefix는 이제 기본값이 None이고 적절한 기본값이 사용되도록 합니다.

버전 3.6에서 변경: dir 매개 변수는 이제 경로류 객체를 받아들입니다.

버전 3.12에서 변경: mkdtemp() now always returns an absolute path, even if dir is relative.

tempfile.gettempdir()

임시 파일에 사용된 디렉터리 이름을 반환합니다. 이것은 이 모듈의 모든 함수에 대한 dir 인자의 기본값을 정의합니다.

파이썬은 표준 디렉터리 목록을 검색하여 호출하는 사용자가 파일을 만들 수 있는 디렉터리를 찾습니다. 목록은 다음과 같습니다:

TMPDIR 환경 변수로 명명된 디렉터리.

TEMP 환경 변수로 명명된 디렉터리.

TMP 환경 변수로 명명된 디렉터리.

플랫폼별 위치:

윈도우에서, 디렉터리 C:\TEMP, C:\TMP, \TEMP 및 \TMP, 이 순서대로.

다른 모든 플랫폼에서, 디렉터리 /tmp, /var/tmp 및 /usr/tmp, 이 순서대로.

최후의 수단으로, 현재 작업 디렉터리.

이 검색 결과는 캐시 됩니다, 아래 tempdir 설명을 참조하십시오.

버전 3.10에서 변경: Always returns a str. Previously it would return any tempdir value regardless of type so long as it was not None.

tempfile.gettempdirb()

gettempdir()과 같지만, 반환 값이 바이트열입니다.

Added in version 3.5.

tempfile.gettempprefix()

임시 파일을 만드는 데 사용된 파일명 접두사를 반환합니다. 디렉터리 구성 요소가 포함되어 있지 않습니다.

tempfile.gettempprefixb()

gettempprefix()와 같지만, 반환 값이 바이트열입니다.

Added in version 3.5.

The module uses a global variable to store the name of the directory used for temporary files returned by gettempdir(). It can be set directly to override the selection process, but this is discouraged. All functions in this module take a dir argument which can be used to specify the directory. This is the recommended approach that does not surprise other unsuspecting code by changing global API behavior.

tempfile.tempdir

When set to a value other than None, this variable defines the default value for the dir argument to the functions defined in this module, including its type, bytes or str. It cannot be a path-like object.

gettempprefix()를 제외한 위의 함수를 호출할 때 tempdir이 None(기본값)이면 gettempdir()에 설명된 알고리즘에 따라 초기화됩니다.

참고

Beware that if you set tempdir to a bytes value, there is a nasty side effect: The global default return type of mkstemp() and mkdtemp() changes to bytes when no explicit prefix, suffix, or dir arguments of type str are supplied. Please do not write code expecting or depending on this. This awkward behavior is maintained for compatibility with the historical implementation.

예

다음은 tempfile 모듈의 일반적인 사용법에 대한 몇 가지 예입니다:

>>> import tempfile

# create a temporary file and write some data to it
>>> fp = tempfile.TemporaryFile()
>>> fp.write(b'Hello world!')
# read data from file
>>> fp.seek(0)
>>> fp.read()
b'Hello world!'
# close the file, it will be removed
>>> fp.close()

# create a temporary file using a context manager
>>> with tempfile.TemporaryFile() as fp:
...     fp.write(b'Hello world!')
...     fp.seek(0)
...     fp.read()
b'Hello world!'
>>>
# file is now closed and removed

# create a temporary file using a context manager
# close the file, use the name to open the file again
>>> with tempfile.NamedTemporaryFile(delete_on_close=False) as fp:
...     fp.write(b'Hello world!')
...     fp.close()
... # the file is closed, but not removed
... # open the file again by using its name
...     with open(fp.name, mode='rb') as f:
...         f.read()
b'Hello world!'
>>>
# file is now removed

# create a temporary directory using the context manager
>>> with tempfile.TemporaryDirectory() as tmpdirname:
...     print('created temporary directory', tmpdirname)
>>>
# directory and contents have been removed

폐지된 함수와 변수

임시 파일을 만드는 역사적인 방법은 먼저 mktemp() 함수를 사용하여 파일 이름을 생성한 다음 이 이름을 사용하여 파일을 만드는 것입니다. 불행히도 mktemp() 호출과 파일을 만들려는 후속 시도 사이에 다른 프로세스가 이 이름으로 파일을 만들 수 있어서 이 방법은 안전하지 않습니다. 해결책은 두 단계를 결합하고 파일을 즉시 만드는 것입니다. 이 접근법이 mkstemp()와 위에서 설명한 다른 함수에서 사용됩니다.

tempfile.mktemp(suffix='', prefix='tmp', dir=None)

버전 2.3부터 폐지됨: 대신 mkstemp()를 사용하십시오.

호출하는 시점에 존재하지 않는 파일의 절대 경로명을 반환합니다. prefix, suffix 및 dir 인자는 바이트열 파일 이름, suffix=None 및 prefix=None이 지원되지 않는다는 점을 제외하고 mkstemp()의 같은 인자와 유사합니다.

경고

이 함수를 사용하면 프로그램에 보안 허점이 생길 수 있습니다. 반환된 파일 이름으로 무언가를 하면서 시간을 보내는 동안, 다른 누군가가 당신에게 펀치를 날릴 수 있습니다. mktemp() 사용은 delete=False 매개 변수를 전달하여 NamedTemporaryFile()로 쉽게 대체할 수 있습니다:

>>> f = NamedTemporaryFile(delete=False)
>>> f.name
'/tmp/tmptjujjt'
>>> f.write(b"Hello World!\n")
13
>>> f.close()
>>> os.unlink(f.name)
>>> os.path.exists(f.name)
False

glob — Unix style pathname pattern expansion

소스 코드: Lib/glob.py [https://github.com/python/cpython/tree/main/Lib/glob.py]

The glob module finds all the pathnames matching a specified pattern according to the rules used by the Unix shell, although results are returned in arbitrary order. No tilde expansion is done, but *, ?, and character ranges expressed with [] will be correctly matched. This is done by using the os.scandir() and fnmatch.fnmatch() functions in concert, and not by actually invoking a subshell.

Note that files beginning with a dot (.) can only be matched by patterns that also start with a dot, unlike fnmatch.fnmatch() or pathlib.Path.glob(). (For tilde and shell variable expansion, use os.path.expanduser() and os.path.expandvars().)

리터럴 일치를 위해서는, 대괄호 안에 메타 문자를 넣습니다. 예를 들어, '[?]'는 '?' 문자와 일치합니다.

The glob module defines the following functions:

glob.glob(pathname, *, root_dir=None, dir_fd=None, recursive=False, include_hidden=False)

Return a possibly empty list of path names that match pathname, which must be a string containing a path specification. pathname can be either absolute (like /usr/src/Python-1.5/Makefile) or relative (like ../../Tools/*/*.gif), and can contain shell-style wildcards. Broken symlinks are included in the results (as in the shell). Whether or not the results are sorted depends on the file system. If a file that satisfies conditions is removed or added during the call of this function, whether a path name for that file will be included is unspecified.

If root_dir is not None, it should be a path-like object specifying the root directory for searching. It has the same effect on glob() as changing the current directory before calling it. If pathname is relative, the result will contain paths relative to root_dir.

This function can support paths relative to directory descriptors with the dir_fd parameter.

recursive가 참이면, “**” 패턴은 모든 파일과 0개 이상의 디렉터리, 서브 디렉터리 및 디렉터리로의 심볼릭 링크와 일치합니다. 패턴 다음에 os.sep이나 os.altsep이 오면, 파일은 일치하지 않습니다.

If include_hidden is true, “**” pattern will match hidden directories.

pathname, recursive를 인자로 감사 이벤트(auditing event) glob.glob을 발생시킵니다.

Raises an auditing event glob.glob/2 with arguments pathname, recursive, root_dir, dir_fd.

참고

커다란 디렉터리 트리에서 “**” 패턴을 사용하면 과도한 시간이 걸릴 수 있습니다.

참고

This function may return duplicate path names if pathname contains multiple “**” patterns and recursive is true.

버전 3.5에서 변경: “**” 를 사용하는 재귀적 glob 지원.

버전 3.10에서 변경: Added the root_dir and dir_fd parameters.

버전 3.11에서 변경: Added the include_hidden parameter.

glob.iglob(pathname, *, root_dir=None, dir_fd=None, recursive=False, include_hidden=False)

실제로 동시에 저장하지 않고 glob()과 같은 값을 산출하는 이터레이터를 반환합니다.

pathname, recursive를 인자로 감사 이벤트(auditing event) glob.glob을 발생시킵니다.

Raises an auditing event glob.glob/2 with arguments pathname, recursive, root_dir, dir_fd.

참고

This function may return duplicate path names if pathname contains multiple “**” patterns and recursive is true.

버전 3.5에서 변경: “**” 를 사용하는 재귀적 glob 지원.

버전 3.10에서 변경: Added the root_dir and dir_fd parameters.

버전 3.11에서 변경: Added the include_hidden parameter.

glob.escape(pathname)

모든 특수 문자('?', '*' 및 '[')를 이스케이프 처리합니다. 이것은 특수 문자가 들어있을 수 있는 임의의 리터럴 문자열을 일치시키려는 경우에 유용합니다. 드라이브/UNC 셰어 포인트의 특수 문자는 이스케이프 되지 않습니다, 예를 들어, 윈도우에서 escape('//?/c:/Quo vadis?.txt')는 '//?/c:/Quo vadis[?].txt'를 반환합니다.

Added in version 3.4.

glob.translate(pathname, *, recursive=False, include_hidden=False, seps=None)

Convert the given path specification to a regular expression for use with re.match(). The path specification can contain shell-style wildcards.

For example:

>>> import glob, re
>>>
>>> regex = glob.translate('**/*.txt', recursive=True, include_hidden=True)
>>> regex
'(?s:(?:.+/)?[^/]*\\.txt)\\Z'
>>> reobj = re.compile(regex)
>>> reobj.match('foo/bar/baz.txt')
<re.Match object; span=(0, 15), match='foo/bar/baz.txt'>

Path separators and segments are meaningful to this function, unlike fnmatch.translate(). By default wildcards do not match path separators, and * pattern segments match precisely one path segment.

If recursive is true, the pattern segment “**” will match any number of path segments.

If include_hidden is true, wildcards can match path segments that start with a dot (.).

A sequence of path separators may be supplied to the seps argument. If not given, os.sep and altsep (if available) are used.

더 보기

pathlib.PurePath.full_match() and pathlib.Path.glob() methods, which call this function to implement pattern matching and globbing.

Added in version 3.13.

Examples

Consider a directory containing the following files: 1.gif, 2.txt, card.gif and a subdirectory sub which contains only the file 3.txt. glob() will produce the following results. Notice how any leading components of the path are preserved.

>>> import glob
>>> glob.glob('./[0-9].*')
['./1.gif', './2.txt']
>>> glob.glob('*.gif')
['1.gif', 'card.gif']
>>> glob.glob('?.gif')
['1.gif']
>>> glob.glob('**/*.txt', recursive=True)
['2.txt', 'sub/3.txt']
>>> glob.glob('./**/', recursive=True)
['./', './sub/']

디렉터리에 .으로 시작하는 파일이 있으면, 기본적으로 일치하지 않습니다. 예를 들어, card.gif 와 .card.gif를 포함하는 디렉터리를 고려하십시오:

>>> import glob
>>> glob.glob('*.gif')
['card.gif']
>>> glob.glob('.c*')
['.card.gif']

더 보기

The fnmatch module offers shell-style filename (not path) expansion.

더 보기

pathlib 모듈은 고수준의 경로 객체를 제공합니다.

fnmatch — Unix filename pattern matching

소스 코드: Lib/fnmatch.py [https://github.com/python/cpython/tree/main/Lib/fnmatch.py]

이 모듈은 유닉스 셸 스타일의 와일드카드를 지원하며, 이는 정규식(re 모듈에서 설명합니다)과는 다릅니다. 셸 스타일 와일드카드에 사용되는 특수 문자는 다음과 같습니다:

패턴

의미

*

모든 것과 일치합니다

?

모든 단일 문자와 일치합니다

[seq]

seq의 모든 문자와 일치합니다.

[!seq]

seq에 없는 모든 문자와 일치합니다

리터럴 일치의 경우, 대괄호 안에 메타 문자를 넣습니다. 예를 들어, '[?]'는 '?' 문자와 일치합니다.

파일명 분리 기호(유닉스에서 '/')는 이 모듈에서 특수하지 않습니다. 경로명 확장은 모듈 glob을 참조하십시오 (glob은 경로명 세그먼트와 일치시키기 위해 filter()를 사용합니다). 마찬가지로, 마침표로 시작하는 파일명은 이 모듈에서 특수하지 않으며, * 및 ? 패턴과 일치합니다.

Also note that functools.lru_cache() with the maxsize of 32768 is used to cache the compiled regex patterns in the following functions: fnmatch(), fnmatchcase(), filter().

fnmatch.fnmatch(name, pat)

Test whether the filename string name matches the pattern string pat, returning True or False. Both parameters are case-normalized using os.path.normcase(). fnmatchcase() can be used to perform a case-sensitive comparison, regardless of whether that’s standard for the operating system.

이 예제는 현재 디렉터리의 확장자 .txt 인 모든 파일 이름을 인쇄합니다:

import fnmatch
import os

for file in os.listdir('.'):
    if fnmatch.fnmatch(file, '*.txt'):
        print(file)

fnmatch.fnmatchcase(name, pat)

Test whether the filename string name matches the pattern string pat, returning True or False; the comparison is case-sensitive and does not apply os.path.normcase().

fnmatch.filter(names, pat)

Construct a list from those elements of the iterable names that match pattern pat. It is the same as [n for n in names if fnmatch(n, pat)], but implemented more efficiently.

fnmatch.translate(pat)

Return the shell-style pattern pat converted to a regular expression for using with re.match().

예제:

>>> import fnmatch, re
>>>
>>> regex = fnmatch.translate('*.txt')
>>> regex
'(?s:.*\\.txt)\\Z'
>>> reobj = re.compile(regex)
>>> reobj.match('foobar.txt')
<re.Match object; span=(0, 10), match='foobar.txt'>

더 보기

모듈 glob

유닉스 셸 스타일 경로 확장.

linecache — Random access to text lines

소스 코드: Lib/linecache.py [https://github.com/python/cpython/tree/main/Lib/linecache.py]

linecache 모듈은 파이썬 소스 파일에서 임의의 줄을 가져올 수 있도록 하는데, 캐시를 사용하여 단일 파일에서 여러 줄을 읽는 일반적인 상황을 내부적으로 최적화하려고 시도합니다. 이것은 traceback 모듈에서 포맷된 트레이스백에 포함할 소스 줄을 가져오는 데 사용됩니다.

tokenize.open() 함수가 파일을 여는 데 사용됩니다. 이 함수는 tokenize.detect_encoding()를 사용하여 파일의 인코딩을 가져옵니다; 인코딩 토큰이 없으면, 파일 인코딩의 기본값은 UTF-8입니다.

linecache 모듈은 다음 함수를 정의합니다:

linecache.getline(filename, lineno, module_globals=None)

filename 파일에서 lineno 줄을 가져옵니다. 이 함수는 절대 예외를 발생시키지 않을 것입니다 — 에러 시 ''를 반환합니다 (발견된 줄의 줄 바꿈 문자는 포함됩니다).

filename이라는 파일이 없으면, 이 함수는 먼저 module_globals에서 PEP 302 [https://peps.python.org/pep-0302/] __loader__를 확인합니다. 그런 로더가 있고 get_source 메서드를 정의하고 있으면, 그것이 소스 줄을 결정합니다 (get_source()가 None을 반환하면, ''이 반환됩니다). 마지막으로, filename이 상대 파일명이면, 모듈 검색 경로, sys.path, 에 있는 항목들에 상대적으로 검색됩니다.

linecache.clearcache()

캐시를 지웁니다. 이전에 getline()를 사용하여 읽은 파일의 줄이 더는 필요하지 않으면 이 함수를 사용하십시오.

linecache.checkcache(filename=None)

캐시의 유효성을 확인합니다. 캐시의 파일이 디스크에서 변경되었을 수 있고, 갱신된 버전이 필요하면 이 함수를 사용하십시오. filename이 생략되면, 캐시의 모든 항목을 검사합니다.

linecache.lazycache(filename, module_globals)

이후 호출에서 module_globals가 None이더라도 getline()을 통해 나중에 해당 줄을 가져올 수 있도록, 파일 기반이 아닌 모듈에 대한 충분한 정보를 캡처합니다. 이렇게 하면 라인이 실제로 필요할 때까지 모듈 전역을 무기한으로 들고 있지 않고도 I/O를 회피합니다.

Added in version 3.5.

예제:

>>> import linecache
>>> linecache.getline(linecache.__file__, 8)
'import sys\n'

shutil — High-level file operations

소스 코드: Lib/shutil.py [https://github.com/python/cpython/tree/main/Lib/shutil.py]

shutil 모듈은 파일과 파일 모음에 대한 여러 가지 고수준 연산을 제공합니다. 특히, 파일 복사와 삭제를 지원하는 함수가 제공됩니다. 개별 파일에 대한 연산에 대해서는, os 모듈도 참조하십시오.

경고

더 고수준의 파일 복사 함수(shutil.copy(), shutil.copy2())조차도 모든 파일 메타 데이터를 복사할 수는 없습니다.

POSIX 플랫폼에서, 이는 ACL뿐만 아니라 파일 소유자와 그룹이 유실됨을 의미합니다. Mac OS에서는, 리소스 포크(resource fork)와 기타 메타 데이터가 사용되지 않습니다. 이는 리소스가 손실되고 파일 유형과 작성자 코드가 올바르지 않음을 의미합니다. 윈도우에서는, 파일 소유자, ACL 및 대체 데이터 스트림(alternate data streams)이 복사되지 않습니다.

디렉터리와 파일 연산

shutil.copyfileobj(fsrc, fdst[, length])

Copy the contents of the file-like object fsrc to the file-like object fdst. The integer length, if given, is the buffer size. In particular, a negative length value means to copy the data without looping over the source data in chunks; by default the data is read in chunks to avoid uncontrolled memory consumption. Note that if the current file position of the fsrc object is not 0, only the contents from the current file position to the end of the file will be copied.

shutil.copyfile(src, dst, *, follow_symlinks=True)

Copy the contents (no metadata) of the file named src to a file named dst and return dst in the most efficient way possible. src and dst are path-like objects or path names given as strings.

dst는 완전한 대상 파일 이름이어야 합니다; 대상 디렉터리 경로를 허용하는 복사는 copy()를 참조하십시오. src와 dst가 같은 파일을 지정하면, SameFileError가 발생합니다.

대상 위치는 쓰기 가능해야 합니다; 그렇지 않으면, OSError 예외가 발생합니다. dst가 이미 존재하면, 교체됩니다. 문자나 블록 장치 및 파이프와 같은 특수 파일은 이 함수로 복사할 수 없습니다.

follow_symlinks가 거짓이고 src가 심볼릭 링크이면, src가 가리키는 파일을 복사하는 대신 새 심볼릭 링크가 만들어집니다.

인자 src, dst로 감사 이벤트 shutil.copyfile을 발생시킵니다.

버전 3.3에서 변경: 예전에는 OSError 대신 IOError를 발생시켰습니다. follow_symlinks 인자가 추가되었습니다. 이제 dst를 반환합니다.

버전 3.4에서 변경: Error 대신 SameFileError를 발생시킵니다. 후자는 전자의 서브 클래스라서, 이 변경은 이전 버전과 호환됩니다.

버전 3.8에서 변경: 파일을 더 효율적으로 복사하기 위해 플랫폼별 빠른 복사(fast-copy) 시스템 호출을 내부적으로 사용할 수 있습니다. 플랫폼 의존적 효율적인 복사 연산 섹션을 참조하십시오.

exception shutil.SameFileError

이 예외는 copyfile()의 소스와 대상이 같은 파일일 때 발생합니다.

Added in version 3.4.

shutil.copymode(src, dst, *, follow_symlinks=True)

Copy the permission bits from src to dst. The file contents, owner, and group are unaffected. src and dst are path-like objects or path names given as strings. If follow_symlinks is false, and both src and dst are symbolic links, copymode() will attempt to modify the mode of dst itself (rather than the file it points to). This functionality is not available on every platform; please see copystat() for more information. If copymode() cannot modify symbolic links on the local platform, and it is asked to do so, it will do nothing and return.

인자 src, dst로 감사 이벤트 shutil.copymode를 발생시킵니다.

버전 3.3에서 변경: follow_symlinks 인자가 추가되었습니다.

shutil.copystat(src, dst, *, follow_symlinks=True)

Copy the permission bits, last access time, last modification time, and flags from src to dst. On Linux, copystat() also copies the “extended attributes” where possible. The file contents, owner, and group are unaffected. src and dst are path-like objects or path names given as strings.

follow_symlinks가 거짓이고 src와 dst가 모두 심볼릭 링크를 참조하면, copystat()은 심볼릭 링크가 참조하는 파일이 아닌 심볼릭 링크 자체에 대해 작동합니다 - src 심볼릭 링크에서 정보를 읽고, dst 심볼릭 링크로 정보를 씁니다.

참고

모든 플랫폼이 심볼릭 링크를 검사하고 수정할 수 있는 기능을 제공하지는 않습니다. 파이썬 자체는 어떤 기능이 로컬에서 사용 가능한지 알려줄 수 있습니다.

os.chmod in os.supports_follow_symlinks가 True이면, copystat()은 심볼릭 링크의 권한 비트를 수정할 수 있습니다.

os.utime in os.supports_follow_symlinks가 True이면, copystat()은 심볼릭 링크의 마지막 액세스와 수정 시간을 수정할 수 있습니다.

os.chflags in os.supports_follow_symlinks가 True이면, copystat()은 심볼릭 링크의 플래그를 수정할 수 있습니다. (os.chflags가 모든 플랫폼에서 사용 가능한 것은 아닙니다.)

이 기능 중 일부나 전부를 사용할 수 없는 플랫폼에서, 심볼릭 링크를 수정하라는 요청을 하면, copystat()은 가능한 모든 것들을 복사합니다. copystat()은 절대 실패를 반환하지 않습니다.

자세한 내용은 os.supports_follow_symlinks를 참조하십시오.

인자 src, dst로 감사 이벤트 shutil.copystat을 발생시킵니다.

버전 3.3에서 변경: follow_symlinks 인자와 리눅스 확장 어트리뷰트 지원을 추가했습니다.

shutil.copy(src, dst, *, follow_symlinks=True)

Copies the file src to the file or directory dst. src and dst should be path-like objects or strings. If dst specifies a directory, the file will be copied into dst using the base filename from src. If dst specifies a file that already exists, it will be replaced. Returns the path to the newly created file.

follow_symlinks가 거짓이고, src가 심볼릭 링크이면, dst는 심볼릭 링크로 만들어집니다. follow_symlinks가 참이고 src가 심볼릭 링크이면, dst는 src가 참조하는 파일의 사본이 됩니다.

copy()는 파일 데이터와 파일의 권한 모드(os.chmod()를 참조하십시오)를 복사합니다. 파일의 생성과 수정 시간과 같은 다른 메타 데이터는 유지되지 않습니다. 원본의 모든 파일 메타 데이터를 유지하려면 대신 copy2()를 사용하십시오.

인자 src, dst로 감사 이벤트 shutil.copyfile을 발생시킵니다.

인자 src, dst로 감사 이벤트 shutil.copymode를 발생시킵니다.

버전 3.3에서 변경: follow_symlinks 인자가 추가되었습니다. 이제 새로 만든 파일의 경로를 반환합니다.

버전 3.8에서 변경: 파일을 더 효율적으로 복사하기 위해 플랫폼별 빠른 복사(fast-copy) 시스템 호출을 내부적으로 사용할 수 있습니다. 플랫폼 의존적 효율적인 복사 연산 섹션을 참조하십시오.

shutil.copy2(src, dst, *, follow_symlinks=True)

copy2()가 파일 메타 데이터 보존도 시도한다는 점을 제외하고는 copy()와 동일합니다.

When follow_symlinks is false, and src is a symbolic link, copy2() attempts to copy all metadata from the src symbolic link to the newly created dst symbolic link. However, this functionality is not available on all platforms. On platforms where some or all of this functionality is unavailable, copy2() will preserve all the metadata it can; copy2() never raises an exception because it cannot preserve file metadata.

copy2()는 copystat()을 사용하여 파일 메타 데이터를 복사합니다. 심볼릭 링크 메타 데이터 수정을 위한 플랫폼 지원에 대한 자세한 정보는 copystat()을 참조하십시오.

인자 src, dst로 감사 이벤트 shutil.copyfile을 발생시킵니다.

인자 src, dst로 감사 이벤트 shutil.copystat을 발생시킵니다.

버전 3.3에서 변경: follow_symlinks 인자를 추가하고, 확장 파일 시스템 어트리뷰트도 복사하려고 합니다 (현재 리눅스만 해당합니다). 이제 새로 만든 파일의 경로를 반환합니다.

버전 3.8에서 변경: 파일을 더 효율적으로 복사하기 위해 플랫폼별 빠른 복사(fast-copy) 시스템 호출을 내부적으로 사용할 수 있습니다. 플랫폼 의존적 효율적인 복사 연산 섹션을 참조하십시오.

shutil.ignore_patterns(*patterns)

이 팩토리 함수는 copytree()의 ignore 인자를 위한 콜러블 함수로 사용할 수 있는 함수를 만드는데, 제공된 glob 스타일 patterns 중 하나와 일치하는 파일과 디렉터리를 무시하도록 합니다. 아래 예를 참조하십시오.

shutil.copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2, ignore_dangling_symlinks=False, dirs_exist_ok=False)

Recursively copy an entire directory tree rooted at src to a directory named dst and return the destination directory. All intermediate directories needed to contain dst will also be created by default.

디렉터리의 권한과 시간은 copystat()으로 복사되고, 개별 파일은 copy2()를 사용하여 복사됩니다.

symlinks가 참이면, 소스 트리의 심볼릭 링크가 새 트리에서 심볼릭 링크로 표시되고 플랫폼이 허용하는 한 원래 링크의 메타 데이터가 복사됩니다; 거짓이거나 생략되면, 링크된 파일의 내용과 메타 데이터가 새 트리에 복사됩니다.

When symlinks is false, if the file pointed to by the symlink doesn’t exist, an exception will be added in the list of errors raised in an Error exception at the end of the copy process. You can set the optional ignore_dangling_symlinks flag to true if you want to silence this exception. Notice that this option has no effect on platforms that don’t support os.symlink().

ignore가 주어지면, copytree()가 방문하는 디렉터리와 os.listdir()가 반환한 이 디렉터리 내용의 리스트를 인자로 수신하는 콜러블 이어야 합니다. copytree()는 재귀적으로 호출되기 때문에, 복사되는 디렉터리마다 ignore 콜러블이 한 번 호출됩니다. 콜러블은 현재 디렉터리에 상대적인 디렉터리와 파일 이름의 시퀀스를 반환해야 합니다 (즉, 두 번째 인자에 있는 항목의 부분집합); 이 이름들은 복사 과정에서 무시됩니다. ignore_patterns()를 사용하여 glob 스타일 패턴을 기반으로 이름을 무시하는 콜러블을 만들 수 있습니다.

예외가 발생하면, 이유 리스트와 함께 Error가 발생합니다.

copy_function이 제공되면, 각 파일을 복사하는 데 사용되는 콜러블 이어야 합니다. 소스 경로와 대상 경로를 인자로 호출됩니다. 기본적으로, copy2()가 사용되지만, 같은 서명을 지원하는 (copy()와 같은) 모든 함수를 사용할 수 있습니다.

If dirs_exist_ok is false (the default) and dst already exists, a FileExistsError is raised. If dirs_exist_ok is true, the copying operation will continue if it encounters existing directories, and files within the dst tree will be overwritten by corresponding files from the src tree.

인자 src, dst로 감사 이벤트 shutil.copytree를 발생시킵니다.

버전 3.2에서 변경: Added the copy_function argument to be able to provide a custom copy function. Added the ignore_dangling_symlinks argument to silence dangling symlinks errors when symlinks is false.

버전 3.3에서 변경: symlinks가 거짓일 때 메타 데이터를 복사합니다. 이제 dst를 반환합니다.

버전 3.8에서 변경: 파일을 더 효율적으로 복사하기 위해 플랫폼별 빠른 복사(fast-copy) 시스템 호출을 내부적으로 사용할 수 있습니다. 플랫폼 의존적 효율적인 복사 연산 섹션을 참조하십시오.

버전 3.8에서 변경: Added the dirs_exist_ok parameter.

shutil.rmtree(path, ignore_errors=False, onerror=None, *, onexc=None, dir_fd=None)

Delete an entire directory tree; path must point to a directory (but not a symbolic link to a directory). If ignore_errors is true, errors resulting from failed removals will be ignored; if false or omitted, such errors are handled by calling a handler specified by onexc or onerror or, if both are omitted, exceptions are propagated to the caller.

This function can support paths relative to directory descriptors.

참고

필요한 fd 기반 함수를 지원하는 플랫폼에서는 기본적으로 rmtree()의 심볼릭 링크 공격 방지 버전이 사용됩니다. 다른 플랫폼에서는, rmtree() 구현이 심볼릭 링크 공격에 취약합니다: 적절한 타이밍과 상황에 따라, 공격자는 파일 시스템에서 심볼릭 링크를 조작하여 다른 방법으로는 액세스할 수 없는 파일을 삭제할 수 있습니다. 응용 프로그램은 rmtree.avoids_symlink_attacks 함수 어트리뷰트를 사용하여 어떤 버전이 사용되는지 판별할 수 있습니다.

If onexc is provided, it must be a callable that accepts three parameters: function, path, and excinfo.

The first parameter, function, is the function which raised the exception; it depends on the platform and implementation. The second parameter, path, will be the path name passed to function. The third parameter, excinfo, is the exception that was raised. Exceptions raised by onexc will not be caught.

The deprecated onerror is similar to onexc, except that the third parameter it receives is the tuple returned from sys.exc_info().

Raises an auditing event shutil.rmtree with arguments path, dir_fd.

버전 3.3에서 변경: 플랫폼이 fd 기반 함수를 지원하면 자동으로 사용되는 심볼릭 링크 공격 방지 버전을 추가했습니다.

버전 3.8에서 변경: 윈도우에서, 정션(junction)을 제거하기 전에 더는 디렉터리 정션의 내용을 삭제하지 않습니다.

버전 3.11에서 변경: Added the dir_fd parameter.

버전 3.12에서 변경: Added the onexc parameter, deprecated onerror.

버전 3.13에서 변경: rmtree() now ignores FileNotFoundError exceptions for all but the top-level path. Exceptions other than OSError and subclasses of OSError are now always propagated to the caller.

rmtree.avoids_symlink_attacks

현재 플랫폼과 구현이 rmtree()의 심볼릭 링크 공격 방지 버전을 제공하는지를 나타냅니다. 현재 이것은 fd 기반 디렉터리 액세스 함수를 지원하는 플랫폼에서만 참입니다.

Added in version 3.3.

shutil.move(src, dst, copy_function=copy2)

Recursively move a file or directory (src) to another location and return the destination.

If dst is an existing directory or a symlink to a directory, then src is moved inside that directory. The destination path in that directory must not already exist.

If dst already exists but is not a directory, it may be overwritten depending on os.rename() semantics.

If the destination is on the current filesystem, then os.rename() is used. Otherwise, src is copied to the destination using copy_function and then removed. In case of symlinks, a new symlink pointing to the target of src will be created as the destination and src will be removed.

If copy_function is given, it must be a callable that takes two arguments, src and the destination, and will be used to copy src to the destination if os.rename() cannot be used. If the source is a directory, copytree() is called, passing it the copy_function. The default copy_function is copy2(). Using copy() as the copy_function allows the move to succeed when it is not possible to also copy the metadata, at the expense of not copying any of the metadata.

인자 src, dst로 감사 이벤트 shutil.move를 발생시킵니다.

버전 3.3에서 변경: 외부 파일 시스템에 대한 명시적 심볼릭 링크 처리를 추가하여, GNU mv의 동작에 맞게 조정했습니다. 이제 dst를 반환합니다.

버전 3.5에서 변경: copy_function 키워드 인자를 추가했습니다.

버전 3.8에서 변경: 파일을 더 효율적으로 복사하기 위해 플랫폼별 빠른 복사(fast-copy) 시스템 호출을 내부적으로 사용할 수 있습니다. 플랫폼 의존적 효율적인 복사 연산 섹션을 참조하십시오.

버전 3.9에서 변경: src와 dst 모두에 대해 경로류 객체를 받아들입니다.

shutil.disk_usage(path)

지정된 경로(path)에 대한 디스크 사용량 통계를 total, used 및 free 어트리뷰트를 갖는 네임드 튜플로 반환합니다. 이들은 바이트 단위의 총, 사용된, 여유 공간의 양입니다. path는 파일이나 디렉터리일 수 있습니다.

참고

On Unix filesystems, path must point to a path within a mounted filesystem partition. On those platforms, CPython doesn’t attempt to retrieve disk usage information from non-mounted filesystems.

Added in version 3.3.

버전 3.8에서 변경: 윈도우에서, path는 이제 파일이나 디렉터리일 수 있습니다.

Availability: Unix, Windows.

shutil.chown(path, user=None, group=None, *, dir_fd=None, follow_symlinks=True)

주어진 path의 소유자 user 및/또는 group을 변경합니다.

user는 시스템 사용자 이름이나 uid 일 수 있습니다; group도 마찬가지입니다. 최소한 하나의 인자가 필요합니다.

하부 함수인 os.chown()도 참조하십시오.

인자 path, user, group으로 감사 이벤트 shutil.chown을 발생시킵니다.

Availability: Unix.

Added in version 3.3.

버전 3.13에서 변경: Added dir_fd and follow_symlinks parameters.

shutil.which(cmd, mode=os.F_OK | os.X_OK, path=None)

주어진 cmd가 호출되면 실행될 실행 파일의 경로를 반환합니다. 아무런 cmd도 호출되지 않을 것이라면, None을 반환합니다.

mode is a permission mask passed to os.access(), by default determining if the file exists and is executable.

path is a “PATH string” specifying the directories to look in, delimited by os.pathsep. When no path is specified, the PATH environment variable is read from os.environ, falling back to os.defpath if it is not set.

On Windows, the current directory is prepended to the path if mode does not include os.X_OK. When the mode does include os.X_OK, the Windows API NeedCurrentDirectoryForExePathW will be consulted to determine if the current directory should be prepended to path. To avoid consulting the current working directory for executables: set the environment variable NoDefaultCurrentDirectoryInExePath.

Also on Windows, the PATHEXT environment variable is used to resolve commands that may not already include an extension. For example, if you call shutil.which("python"), which() will search PATHEXT to know that it should look for python.exe within the path directories. For example, on Windows:

>>> shutil.which("python")
'C:\\Python33\\python.EXE'

This is also applied when cmd is a path that contains a directory component:

>> shutil.which("C:\\Python33\\python")
'C:\\Python33\\python.EXE'

Added in version 3.3.

버전 3.8에서 변경: 이제 bytes 형을 받아들입니다. cmd 형이 bytes이면 결과 형도 bytes입니다.

버전 3.12에서 변경: On Windows, the current directory is no longer prepended to the search path if mode includes os.X_OK and WinAPI NeedCurrentDirectoryForExePathW(cmd) is false, else the current directory is prepended even if it is already in the search path; PATHEXT is used now even when cmd includes a directory component or ends with an extension that is in PATHEXT; and filenames that have no extension can now be found.

exception shutil.Error

이 예외는 다중 파일 연산 중에 발생한 예외를 수집합니다. copytree()의 경우, 예외 인자는 3-튜플(srcname, dstname, exception)의 리스트입니다.

플랫폼 의존적 효율적인 복사 연산

파이썬 3.8부터, 파일 복사를 수반하는 모든 함수(copyfile(), copy(), copy2(), copytree() 및 move())는 파일을 더 효율적으로 복사하기 위해 플랫폼별 “빠른 복사(fast-copy)” 시스템 호출을 사용할 수 있습니다 (bpo-33671 [https://bugs.python.org/issue?@action=redirect&bpo=33671]을 참조하십시오). “빠른 복사”는 복사 연산이 커널 내에서 발생하여, “outfd.write(infd.read())”와 같이 파이썬에서 사용자 공간 버퍼 사용을 피함을 의미합니다.

macOS에서는 fcopyfile [http://www.manpagez.com/man/3/copyfile/]이 (메타 데이터가 아닌) 파일 내용을 복사하는 데 사용됩니다.

On Linux and Solaris os.sendfile() is used.

윈도우에서는 shutil.copyfile()이 더 큰 기본 버퍼 크기(64 KiB 대신 1 MiB)를 사용하고 shutil.copyfileobj()의 memoryview() 기반 변형이 사용됩니다.

빠른 복사 연산이 실패하고 대상 파일에 아무런 데이터도 기록되지 않았으면 shutil은 내부적으로 덜 효율적인 copyfileobj() 함수를 사용하여 조용히 폴 백 됩니다.

버전 3.8에서 변경.

버전 3.14에서 변경: Solaris now uses os.sendfile().

copytree 예

An example that uses the ignore_patterns() helper:

from shutil import copytree, ignore_patterns

copytree(source, destination, ignore=ignore_patterns('*.pyc', 'tmp*'))

이것은 .pyc 파일과 이름이 tmp로 시작하는 파일이나 디렉터리를 제외한 모든 것을 복사합니다.

로깅 호출을 추가하기 위해 ignore 인자를 사용하는 또 다른 예:

from shutil import copytree
import logging

def _logpath(path, names):
    logging.info('Working in %s', path)
    return []   # nothing will be ignored

copytree(source, destination, ignore=_logpath)

rmtree 예

This example shows how to remove a directory tree on Windows where some of the files have their read-only bit set. It uses the onexc callback to clear the readonly bit and reattempt the remove. Any subsequent failure will propagate.

import os, stat
import shutil

def remove_readonly(func, path, _):
    "Clear the readonly bit and reattempt the removal"
    os.chmod(path, stat.S_IWRITE)
    func(path)

shutil.rmtree(directory, onexc=remove_readonly)

아카이브 연산

Added in version 3.2.

버전 3.5에서 변경: xztar 형식에 대한 지원이 추가되었습니다.

압축 및 아카이브 된 파일을 만들고 읽는 고수준 유틸리티도 제공됩니다. 이들은 zipfile과 tarfile 모듈에 의존합니다.

shutil.make_archive(base_name, format[, root_dir[, base_dir[, verbose[, dry_run[, owner[, group[, logger]]]]]]])

아카이브 파일(가령 zip이나 tar)을 만들고 이름을 반환합니다.

base_name is the name of the file to create, including the path, minus any format-specific extension.

format is the archive format: one of “zip” (if the zlib module is available), “tar”, “gztar” (if the zlib module is available), “bztar” (if the bz2 module is available), or “xztar” (if the lzma module is available).

root_dir은 아카이브의 루트 디렉터리가 될 디렉터리입니다, 아카이브의 모든 경로는 이것에 상대적입니다; 예를 들어, 보통 아카이브를 만들기 전에 root_dir로 chdir 합니다.

base_dir은 아카이브를 시작할 디렉터리입니다; 즉, base_dir은 아카이브에 있는 모든 파일과 디렉터리의 공통 접두사가 됩니다. base_dir은 root_dir에 상대적으로 제공되어야 합니다. base_dir과 root_dir을 함께 사용하는 방법은 base_dir을 사용한 아카이브 예를 참조하십시오.

root_dir과 base_dir은 모두 현재 디렉터리가 기본값입니다.

dry_run이 참이면, 아카이브가 만들어지지 않지만, 실행될 연산이 logger에 로그 됩니다.

tar 아카이브를 만들 때 owner와 *group이 사용됩니다. 기본적으로, 현재 소유자와 그룹을 사용합니다.

logger는 PEP 282 [https://peps.python.org/pep-0282/]와 호환되는 객체여야 합니다, 일반적으로 logging.Logger의 인스턴스.

verbose 인자는 사용되지 않으며 폐지되었습니다.

인자 base_name, format, root_dir, base_dir로 감사 이벤트 shutil.make_archive를 발생시킵니다.

참고

This function is not thread-safe when custom archivers registered with register_archive_format() do not support the root_dir argument. In this case it temporarily changes the current working directory of the process to root_dir to perform archiving.

버전 3.8에서 변경: format="tar"로 만들어진 아카이브에 기존 GNU 형식 대신 최신 pax (POSIX.1-2001) 형식이 사용됩니다.

버전 3.10.6에서 변경: This function is now made thread-safe during creation of standard .zip and tar archives.

shutil.get_archive_formats()

아카이브에 지원되는 형식의 리스트를 반환합니다. 반환된 시퀀스의 각 요소는 튜플 (name, description)입니다.

기본적으로 shutil은 다음 형식을 제공합니다:

zip: ZIP 파일 (zlib 모듈을 사용할 수 있으면).

tar: 압축되지 않은 tar 파일. 새 아카이브에 POSIX.1-2001 pax 형식을 사용합니다.

gztar: gzip 된 tar 파일 (zlib 모듈을 사용할 수 있으면).

bztar: bzip2 된 tar 파일 (bz2 모듈을 사용할 수 있으면).

xztar: xz 된 tar 파일 (lzma 모듈을 사용할 수 있으면).

register_archive_format()을 사용하여, 새 형식을 등록하거나 기존 형식에 대해 여러분 자신의 아카이버를 제공할 수 있습니다.

shutil.register_archive_format(name, function[, extra_args[, description]])

name 형식을 위한 아카이버를 등록합니다.

function은 아카이브를 만드는 데 사용되는 콜러블입니다. 콜러블은 만들 파일의 base_name과 그 뒤에 아카이브를 시작할 base_dir(기본값은 os.curdir)를 받습니다. 추가 인자는 키워드 인자로 전달됩니다: owner, group, dry_run 및 logger (make_archive()로 전달됩니다).

If function has the custom attribute function.supports_root_dir set to True, the root_dir argument is passed as a keyword argument. Otherwise the current working directory of the process is temporarily changed to root_dir before calling function. In this case make_archive() is not thread-safe.

주어지면, extra_args는 아카이버 콜러블이 사용될 때 추가 키워드 인자로 사용되는 (name, value) 쌍의 시퀀스입니다.

description은 아카이버 목록을 반환하는 get_archive_formats()에서 사용됩니다. 기본값은 빈 문자열입니다.

버전 3.12에서 변경: Added support for functions supporting the root_dir argument.

shutil.unregister_archive_format(name)

지원되는 형식 리스트에서 name 아카이브 형식을 제거합니다.

shutil.unpack_archive(filename[, extract_dir[, format[, filter]]])

아카이브를 풉니다. filename은 아카이브의 전체 경로입니다.

extract_dir은 아카이브가 풀리는 대상 디렉터리의 이름입니다. 제공되지 않으면, 현재 작업 디렉터리가 사용됩니다.

format은 아카이브 형식입니다: “zip”, “tar”, “gztar”, “bztar” 또는 “xztar” 중 하나. 또는 register_unpack_format()으로 등록된 다른 형식. 제공되지 않으면, unpack_archive()는 아카이브 파일 이름 확장자를 사용하여 그 확장자에 대한 아카이브 해제기가 등록되었는지 확인합니다. 아무것도 발견되지 않으면, ValueError가 발생합니다.

The keyword-only filter argument is passed to the underlying unpacking function. For zip files, filter is not accepted. For tar files, it is recommended to use 'data' (default since Python 3.14), unless using features specific to tar and UNIX-like filesystems. (See Extraction filters for details.)

인자 filename, extract_dir, format으로 감사 이벤트 shutil.unpack_archive를 발생시킵니다.

경고

Never extract archives from untrusted sources without prior inspection. It is possible that files are created outside of the path specified in the extract_dir argument, e.g. members that have absolute filenames starting with “/” or filenames with two dots “..”.

Since Python 3.14, the defaults for both built-in formats (zip and tar files) will prevent the most dangerous of such security issues, but will not prevent all unintended behavior. Read the Hints for further verification section for tar-specific details.

버전 3.7에서 변경: filename과 extract_dir에 대해 경로류 객체를 받아들입니다.

버전 3.12에서 변경: Added the filter argument.

shutil.register_unpack_format(name, extensions, function[, extra_args[, description]])

아카이브 해제기를 등록합니다. name은 형식의 이름이고 extensions는 형식에 해당하는 확장자의 리스트입니다, 가령 Zip 파일의 경우 .zip.

function is the callable that will be used to unpack archives. The callable will receive:

the path of the archive, as a positional argument;

the directory the archive must be extracted to, as a positional argument;

possibly a filter keyword argument, if it was given to unpack_archive();

additional keyword arguments, specified by extra_args as a sequence of (name, value) tuples.

description은 형식을 설명하기 위해 제공될 수 있으며, get_unpack_formats() 함수에 의해 반환됩니다.

shutil.unregister_unpack_format(name)

아카이브 해제 형식을 등록 취소합니다. name은 형식의 이름입니다.

shutil.get_unpack_formats()

아카이브 해제를 위해 등록된 모든 형식의 리스트를 반환합니다. 반환된 시퀀스의 각 요소는 튜플 (name, extensions, description)입니다.

기본적으로 shutil은 다음 형식을 제공합니다:

zip: ZIP 파일 (압축된 파일의 해제는 해당 모듈을 사용할 수 있을 때만 작동합니다).

tar: 압축되지 않은 tar 파일.

gztar: gzip 된 tar 파일 (zlib 모듈을 사용할 수 있으면).

bztar: bzip2 된 tar 파일 (bz2 모듈을 사용할 수 있으면).

xztar: xz 된 tar 파일 (lzma 모듈을 사용할 수 있으면).

register_unpack_format()을 사용하여, 새 형식을 등록하거나 기존 형식에 대한 여러분 자신의 아카이브 해제기를 제공할 수 있습니다.

아카이브 예

이 예에서는, 사용자의 .ssh 디렉터리에 있는 모든 파일을 포함하는 gzip 된 tar 파일 아카이브를 만듭니다:

>>> from shutil import make_archive
>>> import os
>>> archive_name = os.path.expanduser(os.path.join('~', 'myarchive'))
>>> root_dir = os.path.expanduser(os.path.join('~', '.ssh'))
>>> make_archive(archive_name, 'gztar', root_dir)
'/Users/tarek/myarchive.tar.gz'

결과 아카이브에는 다음이 포함됩니다:

$ tar -tzvf /Users/tarek/myarchive.tar.gz
drwx------ tarek/staff       0 2010-02-01 16:23:40 ./
-rw-r--r-- tarek/staff     609 2008-06-09 13:26:54 ./authorized_keys
-rwxr-xr-x tarek/staff      65 2008-06-09 13:26:54 ./config
-rwx------ tarek/staff     668 2008-06-09 13:26:54 ./id_dsa
-rwxr-xr-x tarek/staff     609 2008-06-09 13:26:54 ./id_dsa.pub
-rw------- tarek/staff    1675 2008-06-09 13:26:54 ./id_rsa
-rw-r--r-- tarek/staff     397 2008-06-09 13:26:54 ./id_rsa.pub
-rw-r--r-- tarek/staff   37192 2010-02-06 18:23:10 ./known_hosts

base_dir을 사용한 아카이브 예

이 예에서는, 위의 예와 유사하게, make_archive()를 사용하는 방법을 보여 주지만, 이번에는 base_dir을 사용합니다. 이제 다음 디렉터리 구조가 있습니다:

$ tree tmp
tmp
└── root
    └── structure
        ├── content
            └── please_add.txt
        └── do_not_add.txt

최종 아카이브에는, please_add.txt가 포함되어야 하지만, do_not_add.txt는 포함되지 않아야 합니다. 따라서 다음을 사용합니다:

>>> from shutil import make_archive
>>> import os
>>> archive_name = os.path.expanduser(os.path.join('~', 'myarchive'))
>>> make_archive(
...     archive_name,
...     'tar',
...     root_dir='tmp/root',
...     base_dir='structure/content',
... )
'/Users/tarek/my_archive.tar'

결과 아카이브에 파일을 나열하면 다음과 같습니다:

$ python -m tarfile -l /Users/tarek/myarchive.tar
structure/content/
structure/content/please_add.txt

출력 터미널의 크기 조회하기

shutil.get_terminal_size(fallback=(columns, lines))

터미널 창의 크기를 가져옵니다.

두 차원 각각에 대해, 환경 변수 COLUMNS와 LINES가 각각 확인됩니다. 변수가 정의되고 값이 양의 정수이면 사용됩니다.

COLUMNS나 LINES가 정의되지 않으면 (이것이 일반적입니다), os.get_terminal_size()를 호출하여 sys.__stdout__에 연결된 터미널을 조회합니다.

시스템이 조회를 지원하지 않거나, 터미널에 연결되어 있지 않기 때문에 터미널 크기를 성공적으로 조회할 수 없으면, fallback 매개 변수에 제공된 값이 사용됩니다. fallback의 기본값은 많은 터미널 에뮬레이터에서 사용하는 기본 크기인 (80, 24)입니다.

반환된 값은 os.terminal_size 형의 네임드 튜플입니다.

참조: The Single UNIX Specification, Version 2, Other Environment Variables [https://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html#tag_002_003].

Added in version 3.3.

버전 3.11에서 변경: The fallback values are also used if os.get_terminal_size() returns zeroes.

데이터 지속성

이 장에서 설명하는 모듈은 파이썬 데이터를 디스크에 지속적인 형태로 저장하는 것을 지원합니다. pickle과 marshal 모듈은 많은 파이썬 데이터형을 바이트 스트림으로 바꿀 수 있고 그 바이트열로부터 객체를 재생성할 수 있습니다. 다양한 DBM 관련 모듈은 문자열에서 다른 문자열로의 매핑을 저장하는 일군의 해시 기반 파일 형식을 지원합니다.

이 장에서 설명하는 모듈 목록은 다음과 같습니다:

pickle — Python object serialization

다른 파이썬 모듈과의 관계

marshal 과의 비교

json 과의 비교

데이터 스트림 형식

모듈 인터페이스

HIGHEST_PROTOCOL

DEFAULT_PROTOCOL

dump()

dumps()

load()

loads()

PickleError

PicklingError

UnpicklingError

Pickler

dump()

persistent_id()

dispatch_table

reducer_override()

fast

Unpickler

load()

persistent_load()

find_class()

PickleBuffer

raw()

release()

어떤 것이 피클 되고 역 피클 될 수 있을까요?

클래스 인스턴스 피클링

__getnewargs_ex__()

__getnewargs__()

__getstate__()

__setstate__()

__reduce__()

__reduce_ex__()

외부 객체의 지속성

디스패치 테이블

상태 저장 객체 처리

형, 함수 및 기타 객체에 대한 사용자 정의 환원

아웃 오브 밴드 버퍼

제공자 API

소비자 API

예제

전역 제한하기

성능

예제

copyreg — Register pickle support functions

constructor()

pickle()

예제

shelve — Python object persistence

open()

sync()

close()

제약 사항

Shelf

BsdDbShelf

DbfilenameShelf

예제

marshal — Internal Python object serialization

dump()

load()

dumps()

loads()

version

dbm — Interfaces to Unix “databases”

error

whichdb()

open()

dbm.sqlite3 — SQLite backend for dbm

open()

dbm.gnu — GNU database manager

error

open()

open_flags

firstkey()

nextkey()

reorganize()

sync()

close()

clear()

dbm.ndbm — New Database Manager

error

library

open()

close()

clear()

dbm.dumb — 이식성 있는 DBM 구현

error

open()

sync()

close()

sqlite3 — DB-API 2.0 interface for SQLite databases

Tutorial

Reference

Module functions

connect()

complete_statement()

enable_callback_tracebacks()

register_adapter()

register_converter()

Module constants

LEGACY_TRANSACTION_CONTROL

PARSE_COLNAMES

PARSE_DECLTYPES

SQLITE_OK

SQLITE_DENY

SQLITE_IGNORE

apilevel

paramstyle

sqlite_version

sqlite_version_info

threadsafety

SQLITE_DBCONFIG_DEFENSIVE

SQLITE_DBCONFIG_DQS_DDL

SQLITE_DBCONFIG_DQS_DML

SQLITE_DBCONFIG_ENABLE_FKEY

SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER

SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION

SQLITE_DBCONFIG_ENABLE_QPSG

SQLITE_DBCONFIG_ENABLE_TRIGGER

SQLITE_DBCONFIG_ENABLE_VIEW

SQLITE_DBCONFIG_LEGACY_ALTER_TABLE

SQLITE_DBCONFIG_LEGACY_FILE_FORMAT

SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE

SQLITE_DBCONFIG_RESET_DATABASE

SQLITE_DBCONFIG_TRIGGER_EQP

SQLITE_DBCONFIG_TRUSTED_SCHEMA

SQLITE_DBCONFIG_WRITABLE_SCHEMA

Connection objects

Connection

cursor()

blobopen()

commit()

rollback()

close()

execute()

executemany()

executescript()

create_function()

create_aggregate()

create_window_function()

create_collation()

interrupt()

set_authorizer()

set_progress_handler()

set_trace_callback()

enable_load_extension()

load_extension()

iterdump()

backup()

getlimit()

setlimit()

getconfig()

setconfig()

serialize()

deserialize()

autocommit

in_transaction

isolation_level

row_factory

text_factory

total_changes

Cursor objects

Cursor

execute()

executemany()

executescript()

fetchone()

fetchmany()

fetchall()

close()

setinputsizes()

setoutputsize()

arraysize

connection

description

lastrowid

rowcount

row_factory

Row objects

Row

keys()

Blob objects

Blob

close()

read()

write()

tell()

seek()

PrepareProtocol objects

PrepareProtocol

예외

Warning

Error

sqlite_errorcode

sqlite_errorname

InterfaceError

DatabaseError

DataError

OperationalError

IntegrityError

InternalError

ProgrammingError

NotSupportedError

SQLite 와 파이썬 형

Default adapters and converters (deprecated)

Command-line interface

How-to guides

How to use placeholders to bind values in SQL queries

How to adapt custom Python types to SQLite values

How to write adaptable objects

How to register adapter callables

How to convert SQLite values to custom Python types

Adapter and converter recipes

How to use connection shortcut methods

How to use the connection context manager

How to work with SQLite URIs

How to create and use row factories

How to handle non-UTF-8 text encodings

Explanation

Transaction control

Transaction control via the autocommit attribute

Transaction control via the isolation_level attribute

pickle — Python object serialization

소스 코드: Lib/pickle.py [https://github.com/python/cpython/tree/main/Lib/pickle.py]

pickle 모듈은 파이썬 객체 구조의 직렬화와 역 직렬화를 위한 바이너리 프로토콜을 구현합니다. “피클링(pickling)”은 파이썬 객체 계층 구조가 바이트 스트림으로 변환되는 절차이며, “역 피클링(unpickling)”은 반대 연산으로, (바이너리 파일 이나 바이트열류 객체로 부터의) 바이트 스트림을 객체 계층 구조로 복원합니다. 피클링(그리고 역 피클링)은 “직렬화(serialization)”, “마샬링(marshalling)” [1] 또는 “평탄화(flattening)” 라고도 합니다; 그러나, 혼란을 피하고자, 여기에서 사용된 용어는 “피클링” 과 “역 피클링” 입니다.

경고

pickle 모듈은 안전하지 않습니다. 신뢰할 수 있는 데이터만 언 피클 하십시오.

언 피클 시 임의의 코드를 실행하는 악의적인 피클 데이터를 구성할 수 있습니다. 신뢰할 수 없는 출처에서 왔거나 변조되었을 수 있는 데이터를 절대로 언 피클 하지 마십시오.

변조되지 않았음을 보장하려면 hmac으로 데이터에 서명하는 것을 고려하십시오.

신뢰할 수 없는 데이터를 처리한다면, json과 같은 안전한 직렬화 형식이 더 적합 할 수 있습니다. json 과의 비교를 참조하십시오.

다른 파이썬 모듈과의 관계

marshal 과의 비교

파이썬이 marshal 이라 불리는 좀 더 원시적인 직렬화 모듈을 가지고 있지만, 일반적으로 pickle 은 항상 파이썬 객체를 직렬화하기 위해 선호되는 방법이어야 합니다. marshal 은 주로 파이썬의 .pyc 파일을 지원하기 위해 존재합니다.

pickle 모듈은 marshal과 몇 가지 중요한 점에서 다릅니다:

pickle 모듈은 이미 직렬화된 객체를 추적하므로 나중에 같은 객체에 대한 참조가 다시 직렬화되지 않습니다. marshal 은 이렇게 하지 않습니다.

이는 재귀 객체와 객체 공유에 모두 관련이 있습니다. 재귀 객체는 자신에 대한 참조를 포함하는 객체입니다. 이것은 마샬에 의해 처리되지 않으며, 실제로 재귀 객체를 마샬 하려고 하면 파이썬 인터프리터가 충돌합니다. 객체 공유는 직렬화되는 객체 계층의 다른 위치에서 같은 객체에 대한 다중 참조가 있을 때 발생합니다. pickle 은 그러한 객체를 한 번만 저장하고, 다른 모든 참조가 마스터 복사본을 가리키도록 만듭니다. 공유 객체는 공유된 상태로 유지되는데, 가변 객체의 경우 매우 중요할 수 있습니다.

marshal은 사용자 정의 클래스와 인스턴스를 직렬화하는 데 사용할 수 없습니다. pickle 은 클래스 인스턴스를 투명하게 저장하고 복원할 수 있지만, 클래스 정의는 객체를 저장할 때와 같은 모듈에 존재하고 임포트 할 수 있어야 합니다.

marshal 직렬화 형식은 파이썬 버전 간에 이식성이 보장되지 않습니다. 가장 중요한 일은 .pyc 파일을 지원하는 것이므로, 파이썬 구현자는 필요할 때 직렬화 형식을 과거 호환되지 않는 방식으로 변경할 권리를 갖습니다. pickle 직렬화 형식은, 호환성 있는 피클 프로토콜이 선택되고 여러분의 데이터가 파이썬 2와 파이썬 3의 호환되지 않는 언어 경계를 가로지를 때 피클링과 역 피클링 코드가 두 파이썬 형의 차이점을 다루는 한, 파이썬 배포 간의 과거 호환성을 보장합니다.

json 과의 비교

There are fundamental differences between the pickle protocols and JSON (JavaScript Object Notation) [https://json.org]:

JSON은 텍스트 직렬화 형식(유니코드 텍스트를 출력하지만, 대개는 utf-8 으로 인코딩됩니다)인 반면, pickle은 바이너리 직렬화 형식입니다.

JSON은 사람이 읽을 수 있지만, 피클은 그렇지 않습니다.

JSON은 상호 운용이 가능하며 파이썬 생태계 외부에서 널리 사용되는 반면, 피클은 파이썬으로만 한정됩니다.

JSON은, 기본적으로, 파이썬 내장형 일부만 표시할 수 있으며 사용자 정의 클래스는 표시할 수 없습니다; 피클은 매우 많은 수의 파이썬 형을 나타낼 수 있습니다 (그중 많은 것들은 파이썬의 인트로스펙션 기능을 영리하게 사용하여 자동으로; 복잡한 경우는 특정 객체 API 를 구현해서 해결할 수 있습니다);

pickle과 달리, 신뢰할 수 없는 JSON의 역 직렬화는 그 자체로 임의 코드 실행 취약점을 만들지는 않습니다.

더 보기

json 모듈: JSON 직렬화와 역 직렬화를 가능하게 하는 표준 라이브러리 모듈.

데이터 스트림 형식

The data format used by pickle is Python-specific. This has the advantage that there are no restrictions imposed by external standards such as JSON (which can’t represent pointer sharing); however it means that non-Python programs may not be able to reconstruct pickled Python objects.

기본적으로, pickle 데이터 포맷은 상대적으로 간결한 바이너리 표현을 사용합니다. 최적의 크기 특성이 필요하다면, 피클 된 데이터를 효율적으로 압축 할 수 있습니다.

모듈 pickletools 에는 pickle 에 의해 생성된 데이터 스트림을 분석하는 도구가 있습니다. pickletools 소스 코드에는 피클 프로토콜에서 사용되는 옵코드(opcode)에 대한 광범위한 주석이 있습니다.

현재 피클링에 쓸 수 있는 6가지 프로토콜이 있습니다. 사용된 프로토콜이 높을수록, 생성된 피클을 읽으려면 더 최신 파이썬 버전이 필요합니다.

프로토콜 버전 0은 최초의 “사람이 읽을 수 있는” 프로토콜이며 이전 버전의 파이썬과 과거 호환됩니다.

프로토콜 버전 1은 역시 이전 버전의 파이썬과 호환되는 오래된 바이너리 형식입니다.

Protocol version 2 was introduced in Python 2.3. It provides much more efficient pickling of new-style classes. Refer to PEP 307 [https://peps.python.org/pep-0307/] for information about improvements brought by protocol 2.

프로토콜 버전 3은 파이썬 3.0에서 추가되었습니다. 명시적으로 bytes 객체를 지원하며 파이썬 2.x에서 역 피클 될 수 없습니다. 이것은 파이썬 3.0–3.7에서 기본 프로토콜이었습니다.

Protocol version 4 was added in Python 3.4. It adds support for very large objects, pickling more kinds of objects, and some data format optimizations. This was the default protocol in Python 3.8–3.13. Refer to PEP 3154 [https://peps.python.org/pep-3154/] for information about improvements brought by protocol 4.

Protocol version 5 was added in Python 3.8. It adds support for out-of-band data and speedup for in-band data. It is the default protocol starting with Python 3.14. Refer to PEP 574 [https://peps.python.org/pep-0574/] for information about improvements brought by protocol 5.

참고

직렬화는 지속성보다 더 원시적인 개념입니다; pickle 이 파일 객체를 읽거나 쓰기는 하지만, 지속적인 객체의 이름 지정도 (더 복잡한) 지속적인 객체에 대한 동시 액세스 문제도 처리하지 않습니다. pickle 모듈은 복잡한 객체를 바이트 스트림으로 변환할 수 있고 바이트 스트림을 같은 내부 구조를 가진 객체로 변환할 수 있습니다. 아마도 이러한 바이트 스트림으로 할 가장 분명한 작업은 파일에 쓰는 것이겠지만, 네트워크를 통해 보내거나 데이터베이스에 저장하는 것도 고려할 수 있습니다. shelve 모듈은 DBM 스타일의 데이터베이스 파일에 객체를 피클/역 피클 하는 간단한 인터페이스를 제공합니다.

모듈 인터페이스

객체 계층 구조를 직렬화하려면, 단순히 dumps() 함수를 호출하면 됩니다. 마찬가지로, 데이터 스트림을 역 직렬화하려면 loads() 함수를 호출합니다. 그러나, 직렬화와 역 직렬화에 대한 더 많은 제어를 원하면, 각각 Pickler 나 Unpickler 객체를 만들 수 있습니다.

pickle 모듈은 다음과 같은 상수를 제공합니다:

pickle.HIGHEST_PROTOCOL

정수, 사용 가능한 가장 높은 프로토콜 버전. 이 값은 함수 dump()와 dumps() 그리고 Pickler 생성자에 protocol 값으로 전달될 수 있습니다.

pickle.DEFAULT_PROTOCOL

An integer, the default protocol version used for pickling. May be less than HIGHEST_PROTOCOL. Currently the default protocol is 5, introduced in Python 3.8 and incompatible with previous versions. This version introduces support for out-of-band buffers, where PEP 3118 [https://peps.python.org/pep-3118/]-compatible data can be transmitted separately from the main pickle stream.

버전 3.0에서 변경: 기본 프로토콜은 3입니다.

버전 3.8에서 변경: 기본 프로토콜은 4입니다.

버전 3.14에서 변경: The default protocol is 5.

pickle 모듈은 피클링 절차를 보다 편리하게 하려고 다음과 같은 함수를 제공합니다:

pickle.dump(obj, file, protocol=None, *, fix_imports=True, buffer_callback=None)

객체 obj 의 피클 된 표현을 열린 파일 객체 file 에 씁니다. 이것은 Pickler(file, protocol).dump(obj) 와 동등합니다.

인자 file, protocol, fix_imports 및 buffer_callback은 Pickler 생성자에서와 같은 의미입니다.

버전 3.8에서 변경: buffer_callback 인자가 추가되었습니다.

pickle.dumps(obj, protocol=None, *, fix_imports=True, buffer_callback=None)

객체 obj의 피클 된 표현을 파일에 쓰는 대신 bytes 객체로 반환합니다.

인자 protocol, fix_imports 및 buffer_callback은 Pickler 생성자에서와 같은 의미입니다.

버전 3.8에서 변경: buffer_callback 인자가 추가되었습니다.

pickle.load(file, *, fix_imports=True, encoding='ASCII', errors='strict', buffers=None)

열린 파일 객체 file 에서 객체의 피클 된 표현을 읽고, 그 안에 지정된 객체 계층 구조를 재구성하여 반환합니다. 이것은 Unpickler(file).load() 와 동등합니다.

피클의 프로토콜 버전이 자동으로 감지되므로 프로토콜 인자가 필요하지 않습니다. 객체의 피클 된 표현 뒤에 남는 바이트열은 무시됩니다.

인자 file, fix_imports, encoding, errors, strict 및 buffers는 Unpickler 생성자에서와 같은 의미입니다.

버전 3.8에서 변경: buffers 인자가 추가되었습니다.

pickle.loads(data, /, *, fix_imports=True, encoding='ASCII', errors='strict', buffers=None)

객체의 피클 된 표현 data의 재구성된 객체 계층 구조를 반환합니다. data는 바이트열류 객체여야 합니다.

피클의 프로토콜 버전이 자동으로 감지되므로 프로토콜 인자가 필요하지 않습니다. 객체의 피클 된 표현 뒤에 남는 바이트열은 무시됩니다.

Arguments fix_imports, encoding, errors, strict and buffers have the same meaning as in the Unpickler constructor.

버전 3.8에서 변경: buffers 인자가 추가되었습니다.

pickle 모듈은 세 가지 예외를 정의합니다:

exception pickle.PickleError

Common base class for the other pickling exceptions. It inherits from Exception.

exception pickle.PicklingError

Error raised when an unpicklable object is encountered by Pickler. It inherits from PickleError.

어떤 종류의 객체가 피클 될 수 있는지 배우려면 어떤 것이 피클 되고 역 피클 될 수 있을까요?를 참조하십시오.

exception pickle.UnpicklingError

Error raised when there is a problem unpickling an object, such as a data corruption or a security violation. It inherits from PickleError.

역 피클링 중에 다른 예외도 발생할 수 있음에 유의하십시오. AttributeError, EOFError, ImportError, IndexError 등이 발생할 수 있지만, 이에 국한되지는 않습니다.

pickle 모듈은 세 개의 클래스를 노출합니다, Pickler, Unpickler 및 PickleBuffer:

class pickle.Pickler(file, protocol=None, *, fix_imports=True, buffer_callback=None)

피클 데이터 스트림을 쓸 바이너리 파일을 받아들입니다.

선택적 protocol 인자(정수)는 피클러가 주어진 프로토콜을 사용하도록 지시합니다; 지원되는 프로토콜은 0부터 HIGHEST_PROTOCOL 입니다. 지정하지 않으면 기본값은 DEFAULT_PROTOCOL 입니다. 음수가 지정되면, HIGHEST_PROTOCOL 이 선택됩니다.

file 인자에는 단일 바이트열 인자를 받아들이는 write() 메서드가 있어야 합니다. 따라서 바이너리 쓰기를 위해 열린 디스크 상의 파일, io.BytesIO 인스턴스 또는 이 인터페이스를 충족시키는 다른 사용자 정의 객체일 수 있습니다.

fix_imports 가 참이고 protocol 이 3보다 작으면, pickle은 새로운 파이썬 3 이름을 파이썬 2에서 사용된 이전 모듈 이름에 매핑하려고 시도하여, 파이썬 2에서 피클 데이터 스트림을 읽을 수 있도록 합니다.

If buffer_callback is None (the default), buffer views are serialized into file as part of the pickle stream.

If buffer_callback is not None, then it can be called any number of times with a buffer view. If the callback returns a false value (such as None), the given buffer is out-of-band; otherwise the buffer is serialized in-band, i.e. inside the pickle stream.

It is an error if buffer_callback is not None and protocol is None or smaller than 5.

버전 3.8에서 변경: buffer_callback 인자가 추가되었습니다.

dump(obj)

생성자에 주어진 열린 파일 객체에 obj 의 피클 된 표현을 씁니다.

persistent_id(obj)

기본적으로 아무것도 하지 않습니다. 이것은 서브 클래스가 재정의할 수 있게 하려고 존재합니다.

persistent_id() 가 None 을 반환하면, obj 는 보통 때처럼 피클 됩니다. 다른 값은 Pickler 가 obj 의 지속성(persistent) ID로 반환 값을 출력하도록 합니다. 이 지속성 ID의 의미는 Unpickler.persistent_load() 에 의해 정의되어야 합니다. persistent_id() 에 의해 반환된 값 자체는 지속성 ID를 가질 수 없음에 유의하십시오.

자세한 내용과 사용 예는 외부 객체의 지속성를 참조하십시오.

버전 3.13에서 변경: Add the default implementation of this method in the C implementation of Pickler.

dispatch_table

A pickler object’s dispatch table is a registry of reduction functions of the kind which can be declared using copyreg.pickle(). It is a mapping whose keys are classes and whose values are reduction functions. A reduction function takes a single argument of the associated class and should conform to the same interface as a __reduce__() method.

기본적으로, 피클러 객체는 dispatch_table 어트리뷰트를 가지지 않을 것이고, 대신 copyreg 모듈에 의해 관리되는 전역 디스패치 테이블을 사용할 것입니다. 그러나 특정 피클러 객체의 피클링을 사용자 정의하기 위해서 dispatch_table 어트리뷰트를 딕셔너리류 객체로 설정할 수 있습니다. 또는, Pickler 의 서브 클래스가 dispatch_table 어트리뷰트를 가지고 있다면, 이 클래스의 인스턴스를 위한 기본 디스패치 테이블로 사용됩니다.

사용 예는 디스패치 테이블을 참조하십시오.

Added in version 3.3.

reducer_override(obj)

Special reducer that can be defined in Pickler subclasses. This method has priority over any reducer in the dispatch_table. It should conform to the same interface as a __reduce__() method, and can optionally return NotImplemented to fallback on dispatch_table-registered reducers to pickle obj.

자세한 예는 형, 함수 및 기타 객체에 대한 사용자 정의 환원을 참조하십시오.

Added in version 3.8.

fast

폐지되었습니다. 참값으로 설정된 경우 빠른 모드를 활성화합니다. 빠른 모드는 메모 사용을 비활성화하므로, 불필요한 PUT 옵코드를 생성하지 않아 피클링 절차의 속도를 높입니다. 자신을 참조하는 객체에 사용되면 안 됩니다. 그렇지 않으면 Pickler 가 무한 재귀에 빠집니다.

더 간결한 피클이 필요하면 pickletools.optimize() 를 사용하십시오.

class pickle.Unpickler(file, *, fix_imports=True, encoding='ASCII', errors='strict', buffers=None)

피클 데이터 스트림을 읽는 데 사용될 바이너리 파일을 받아들입니다.

피클의 프로토콜 버전이 자동으로 감지되므로 프로토콜 인자가 필요하지 않습니다.

인자 file 에는 세 가지 메서드가 있어야 합니다, io.BufferedIOBase 인터페이스 처럼, 정수 인자를 받아들이는 read() 메서드, 버퍼 인자를 받아들이는 readinto() 메서드 그리고 인자가 없는 readline() 메서드. 따라서 file 은 바이너리 읽기를 위해 열린 디스크 상의 파일, io.BytesIO 객체 또는 이 인터페이스를 만족하는 다른 사용자 정의 객체일 수 있습니다.

선택적 인자 fix_imports, encoding 및 errors는 파이썬 2에서 생성된 피클 스트림에 대한 호환성 지원을 제어하는 데 사용됩니다. fix_imports 가 참이면, pickle은 이전 파이썬 2 이름을 파이썬 3에서 사용된 새로운 이름으로 매핑하려고 합니다. encoding 과 errors 는 파이썬 2에 의해 피클 된 8비트 문자열 인스턴스를 디코딩하는 방법을 pickle에게 알려줍니다. 기본값은 각각 ‘ASCII’와 ‘strict’ 입니다. encoding 은 ‘bytes’ 가 될 수 있는데, 8비트 문자열 인스턴스를 바이트열 객체로 읽습니다. NumPy 배열과 파이썬 2에서 피클 된 datetime, date 및 time 인스턴스를 역 피클링하려면 encoding='latin1'을 사용해야 합니다.

If buffers is None (the default), then all data necessary for deserialization must be contained in the pickle stream. This means that the buffer_callback argument was None when a Pickler was instantiated (or when dump() or dumps() was called).

If buffers is not None, it should be an iterable of buffer-enabled objects that is consumed each time the pickle stream references an out-of-band buffer view. Such buffers have been given in order to the buffer_callback of a Pickler object.

버전 3.8에서 변경: buffers 인자가 추가되었습니다.

load()

생성자에 주어진 열린 파일 객체에서 객체의 피클 된 표현을 읽고, 그 안에 지정된 객체 계층 구조를 재구성하여 반환합니다. 객체의 피클 된 표현 뒤에 남는 바이트열은 무시됩니다.

persistent_load(pid)

기본적으로 UnpicklingError를 발생시킵니다.

정의되면, persistent_load() 는 지속성 ID pid 로 지정된 객체를 반환해야 합니다. 유효하지 않은 지속성 ID가 발견되면 UnpicklingError를 일으켜야 합니다.

자세한 내용과 사용 예는 외부 객체의 지속성를 참조하십시오.

버전 3.13에서 변경: Add the default implementation of this method in the C implementation of Unpickler.

find_class(module, name)

필요하면 module 을 임포트하고 거기에서 name 이라는 객체를 반환합니다. 여기서 module 및 name 인자는 str 객체입니다. 그 이름이 제시하는 것과는 달리, find_class() 는 함수를 찾는 데에도 사용됨에 유의하십시오.

로드되는 객체의 형과 로드 방법을 제어하기 위해 서브 클래스는 이것을 재정의할 수 있고, 잠재적으로 보안 위험을 감소시킵니다. 자세한 내용은 전역 제한하기를 참조하십시오.

module, name을 인자로 감사 이벤트(auditing event) pickle.find_class를 발생시킵니다.

class pickle.PickleBuffer(buffer)

피클 가능한 데이터를 나타내는 버퍼의 래퍼. buffer는 바이트열류 객체나 N-차원 배열과 같은 버퍼 제공 객체여야 합니다.

PickleBuffer 자체가 버퍼 제공자이므로, memoryview와 같은 버퍼 제공 객체를 기대하는 다른 API로 전달할 수 있습니다.

PickleBuffer 객체는 피클 프로토콜 5 이상만 사용하여 직렬화할 수 있습니다. 그들은 아웃 오브 밴드 직렬화 대상입니다.

Added in version 3.8.

raw()

이 버퍼의 하부 메모리 영역의 memoryview를 반환합니다. 반환된 객체는 B (부호 없는 바이트) 형식의 1-차원 C 연속 메모리 뷰입니다. 버퍼가 C나 포트란 연속적이지 않으면 BufferError가 발생합니다.

release()

PickleBuffer 객체에 의해 노출된 하부 버퍼를 해제합니다.

어떤 것이 피클 되고 역 피클 될 수 있을까요?

다음 형을 피클 할 수 있습니다:

built-in constants (None, True, False, Ellipsis, and NotImplemented);

integers, floating-point numbers, complex numbers;

strings, bytes, bytearrays;

tuples, lists, sets, and dictionaries containing only picklable objects;

functions (built-in and user-defined) accessible from the top level of a module (using def, not lambda);

classes accessible from the top level of a module;

instances of such classes whose the result of calling __getstate__() is picklable (see section 클래스 인스턴스 피클링 for details).

피클 가능하지 않은 객체를 피클 하려고 하면 PicklingError 예외가 발생합니다; 이런 일이 일어났을 때, 특정할 수 없는 길이의 바이트열이 하부 파일에 이미 기록되었을 수 있습니다. 매우 재귀적인 데이터 구조를 피클 하려고 하면 최대 재귀 깊이를 초과할 수 있고, 이때 RecursionError 가 발생합니다. sys.setrecursionlimit() 을 사용하여 이 제한을 조심스럽게 올릴 수 있습니다.

Note that functions (built-in and user-defined) are pickled by fully qualified name, not by value. [2] This means that only the function name is pickled, along with the name of the containing module and classes. Neither the function’s code, nor any of its function attributes are pickled. Thus the defining module must be importable in the unpickling environment, and the module must contain the named object, otherwise an exception will be raised. [3]

Similarly, classes are pickled by fully qualified name, so the same restrictions in the unpickling environment apply. Note that none of the class’s code or data is pickled, so in the following example the class attribute attr is not restored in the unpickling environment:

class Foo:
    attr = 'A class attribute'

picklestring = pickle.dumps(Foo)

These restrictions are why picklable functions and classes must be defined at the top level of a module.

Similarly, when class instances are pickled, their class’s code and data are not pickled along with them. Only the instance data are pickled. This is done on purpose, so you can fix bugs in a class or add methods to the class and still load objects that were created with an earlier version of the class. If you plan to have long-lived objects that will see many versions of a class, it may be worthwhile to put a version number in the objects so that suitable conversions can be made by the class’s __setstate__() method.

클래스 인스턴스 피클링

이 절에서는 클래스 인스턴스를 피클 및 역 피클 하는 방법을 정의, 사용자 정의 및 제어할 수 있는 일반적인 메커니즘을 설명합니다.

In most cases, no additional code is needed to make instances picklable. By default, pickle will retrieve the class and the attributes of an instance via introspection. When a class instance is unpickled, its __init__() method is usually not invoked. The default behaviour first creates an uninitialized instance and then restores the saved attributes. The following code shows an implementation of this behaviour:

def save(obj):
    return (obj.__class__, obj.__dict__)

def restore(cls, attributes):
    obj = cls.__new__(cls)
    obj.__dict__.update(attributes)
    return obj

클래스는 다음과 같은 하나 이상의 특수 메서드를 제공하여 기본 동작을 변경할 수 있습니다:

object.__getnewargs_ex__()

프로토콜 2 이상에서, __getnewargs_ex__() 메서드를 구현하는 클래스는 역 피클링 때 __new__() 메서드에 전달되는 값을 지시할 수 있습니다. 이 메서드는 (args, kwargs) 쌍을 반환해야 합니다. args 는 위치 인자의 튜플이고 kwargs 는 이름있는 인자의 딕셔너리인데, 객체를 구성하는 데 사용됩니다. 그것들은 역 피클링 때 __new__() 메서드로 전달될 것입니다.

클래스의 __new__() 메서드에 키워드 전용 인자가 필요하면 이 메서드를 구현해야 합니다. 그렇지 않으면 호환성을 위해 __getnewargs__() 를 구현하는 것이 좋습니다.

버전 3.6에서 변경: __getnewargs_ex__() 는 이제 프로토콜 2와 3에서 사용됩니다.

object.__getnewargs__()

이 메서드는 __getnewargs_ex__() 와 비슷한 목적을 수행하지만, 위치 인자만 지원합니다. 역 피클링 때 __new__() 메서드에 전달될 인자의 튜플 args 를 반환해야 합니다.

__getnewargs_ex__() 가 정의되면 __getnewargs__() 는 호출되지 않습니다.

버전 3.6에서 변경: 파이썬 3.6 이전에는, 프로토콜 2와 3에서 __getnewargs_ex__() 대신 __getnewargs__() 가 호출되었습니다.

object.__getstate__()

Classes can further influence how their instances are pickled by overriding the method __getstate__(). It is called and the returned object is pickled as the contents for the instance, instead of a default state. There are several cases:

For a class that has no instance __dict__ and no __slots__, the default state is None.

For a class that has an instance __dict__ and no __slots__, the default state is self.__dict__.

For a class that has an instance __dict__ and __slots__, the default state is a tuple consisting of two dictionaries: self.__dict__, and a dictionary mapping slot names to slot values. Only slots that have a value are included in the latter.

For a class that has __slots__ and no instance __dict__, the default state is a tuple whose first item is None and whose second item is a dictionary mapping slot names to slot values described in the previous bullet.

버전 3.11에서 변경: Added the default implementation of the __getstate__() method in the object class.

object.__setstate__(state)

역 피클링 때, 클래스가 __setstate__() 를 정의하면, 그것은 역 피클 된 상태(state)로 호출됩니다. 이 경우 상태 객체가 딕셔너리일 필요는 없습니다. 그렇지 않으면, 피클 된 상태는 딕셔너리 여야하고 그 항목이 새 인스턴스의 딕셔너리에 삽입됩니다.

참고

If __reduce__() returns a state with value None at pickling, the __setstate__() method will not be called upon unpickling.

Refer to the section 상태 저장 객체 처리 for more information about how to use the methods __getstate__() and __setstate__().

참고

At unpickling time, some methods like __getattr__(), __getattribute__(), or __setattr__() may be called upon the instance. In case those methods rely on some internal invariant being true, the type should implement __new__() to establish such an invariant, as __init__() is not called when unpickling an instance.

As we shall see, pickle does not use directly the methods described above. In fact, these methods are part of the copy protocol which implements the __reduce__() special method. The copy protocol provides a unified interface for retrieving the data necessary for pickling and copying objects. [4]

Although powerful, implementing __reduce__() directly in your classes is error prone. For this reason, class designers should use the high-level interface (i.e., __getnewargs_ex__(), __getstate__() and __setstate__()) whenever possible. We will show, however, cases where using __reduce__() is the only option or leads to more efficient pickling or both.

object.__reduce__()

인터페이스는 현재 다음과 같이 정의됩니다. __reduce__() 메서드는 아무런 인자도 받아들이지 않으며 문자열이나 바람직하게는 튜플을 반환합니다 (반환된 객체는 흔히 “환원 값(reduce value)”이라고 불립니다).

문자열이 반환되면, 문자열은 전역 변수의 이름으로 해석되어야 합니다. 모듈에 상대적인 객체의 지역 이름이어야 합니다; pickle 모듈은 객체의 모듈을 결정하기 위해 모듈 이름 공간을 검색합니다. 이 동작은 일반적으로 싱글톤에 유용합니다.

튜플이 반환될 때는, 길이가 2나 6이 되어야 합니다. 선택적인 항목은 생략되거나 None 이 값으로 제공될 수 있습니다. 각 항목의 의미는 순서대로 다음과 같습니다:

객체의 초기 버전을 만들기 위해 호출할 콜러블 객체.

콜러블 객체에 대한 인자의 튜플. 콜러블 객체가 인자를 받아들이지 않으면 빈 튜플을 제공해야 합니다.

선택적으로, 객체의 상태. 앞에서 설명한 대로 객체의 __setstate__() 메서드에 전달됩니다. 객체에 그런 메서드가 없다면, 그 값은 딕셔너리 여야 하며 객체의 __dict__ 어트리뷰트에 추가됩니다.

Optionally, an iterator (and not a sequence) yielding successive items. These items will be appended to the object either using obj.append(item) or, in batch, using obj.extend(list_of_items). This is primarily used for list subclasses, but may be used by other classes as long as they have append and extend methods with the appropriate signature. (Whether append() or extend() is used depends on which pickle protocol version is used as well as the number of items to append, so both must be supported.)

선택적으로, 연속적인 키-값 쌍을 생성하는 이터레이터(시퀀스가 아닙니다). 이 항목들은 obj[key] = value 를 사용하여 객체에 저장됩니다. 이것은 주로 딕셔너리 서브 클래스에 사용되지만, __setitem__() 을 구현하는 한 다른 클래스에서 사용될 수 있습니다.

선택적으로, (obj, state) 서명을 가진 콜러블. 이 콜러블은 obj의 정적 __setstate__() 메서드 대신에 특정 객체의 상태 갱신 동작을 프로그래밍 방식으로 제어할 수 있도록 합니다. None이 아니면, 이 콜러블은 obj의 __setstate__()보다 우선 합니다.

Added in version 3.8: 선택적인 여섯 번째 튜플 항목 (obj, state)가 추가되었습니다.

object.__reduce_ex__(protocol)

또는, __reduce_ex__() 메서드를 정의할 수 있습니다. 유일한 차이점은 이 메서드가 프로토콜 버전인 단일 정수 인자를 받아들여야 한다는 것입니다. 정의되면, pickle은 __reduce__() 메서드보다 선호합니다. 또한, __reduce__() 는 자동으로 확장 버전의 동의어가 됩니다. 이 메서드의 주된 용도는 구형 파이썬 배포를 위해 과거 호환성 있는 환원 값을 제공하는 것입니다.

외부 객체의 지속성

객체 지속성의 효용을 위해, pickle 모듈은 피클 된 데이터 스트림 밖의 객체에 대한 참조 개념을 지원합니다. 이러한 객체는 지속성 ID에 의해 참조되며, 영숫자 문자열(프로토콜 0의 경우) [5] 또는 임의의 객체(모든 최신 프로토콜의 경우)여야 합니다.

그러한 지속성 ID의 해석은 pickle 모듈에 의해 정의되지 않습니다; 이 해석을 피클러와 역 피클러의 사용자 정의 메서드에 위임합니다, 각각 persistent_id()와 persistent_load().

지속성 ID를 가진 객체를 피클 하기 위해서, 피클러는 객체를 인자로 받아서 그 객체에 대해 None 또는 지속성 ID를 반환하는 사용자 정의 persistent_id() 메서드가 있어야 합니다. None 이 반환되면, 피클러는 단순히 객체를 피클 합니다. 지속성 ID 문자열이 반환되면, 피클러는 마커와 함께 해당 객체를 피클 하여 역 피클러가 이를 지속성 ID로 인식하게 합니다.

외부 객체를 역 피클 하려면, 역 피클러는 지속성 ID 객체를 받아들여 참조된 객체를 반환하는 사용자 정의 persistent_load() 메서드를 가져야 합니다.

다음은 지속성 ID를 외부 객체를 참조로 피클 하는데 사용하는 방법을 보여주는 포괄적인 예입니다.

# Simple example presenting how persistent ID can be used to pickle
# external objects by reference.

import pickle
import sqlite3
from collections import namedtuple

# Simple class representing a record in our database.
MemoRecord = namedtuple("MemoRecord", "key, task")

class DBPickler(pickle.Pickler):

    def persistent_id(self, obj):
        # Instead of pickling MemoRecord as a regular class instance, we emit a
        # persistent ID.
        if isinstance(obj, MemoRecord):
            # Here, our persistent ID is simply a tuple, containing a tag and a
            # key, which refers to a specific record in the database.
            return ("MemoRecord", obj.key)
        else:
            # If obj does not have a persistent ID, return None. This means obj
            # needs to be pickled as usual.
            return None

class DBUnpickler(pickle.Unpickler):

    def __init__(self, file, connection):
        super().__init__(file)
        self.connection = connection

    def persistent_load(self, pid):
        # This method is invoked whenever a persistent ID is encountered.
        # Here, pid is the tuple returned by DBPickler.
        cursor = self.connection.cursor()
        type_tag, key_id = pid
        if type_tag == "MemoRecord":
            # Fetch the referenced record from the database and return it.
            cursor.execute("SELECT * FROM memos WHERE key=?", (str(key_id),))
            key, task = cursor.fetchone()
            return MemoRecord(key, task)
        else:
            # Always raises an error if you cannot return the correct object.
            # Otherwise, the unpickler will think None is the object referenced
            # by the persistent ID.
            raise pickle.UnpicklingError("unsupported persistent object")

def main():
    import io
    import pprint

    # Initialize and populate our database.
    conn = sqlite3.connect(":memory:")
    cursor = conn.cursor()
    cursor.execute("CREATE TABLE memos(key INTEGER PRIMARY KEY, task TEXT)")
    tasks = (
        'give food to fish',
        'prepare group meeting',
        'fight with a zebra',
        )
    for task in tasks:
        cursor.execute("INSERT INTO memos VALUES(NULL, ?)", (task,))

    # Fetch the records to be pickled.
    cursor.execute("SELECT * FROM memos")
    memos = [MemoRecord(key, task) for key, task in cursor]
    # Save the records using our custom DBPickler.
    file = io.BytesIO()
    DBPickler(file).dump(memos)

    print("Pickled records:")
    pprint.pprint(memos)

    # Update a record, just for good measure.
    cursor.execute("UPDATE memos SET task='learn italian' WHERE key=1")

    # Load the records from the pickle data stream.
    file.seek(0)
    memos = DBUnpickler(file, conn).load()

    print("Unpickled records:")
    pprint.pprint(memos)

if __name__ == '__main__':
    main()

디스패치 테이블

피클링에 의존하는 다른 코드를 방해하지 않고 일부 클래스의 피클링을 사용자 정의하려면, 사설 디스패치 테이블을 갖는 피클러를 만들 수 있습니다.

The global dispatch table managed by the copyreg module is available as copyreg.dispatch_table. Therefore, one may choose to use a modified copy of copyreg.dispatch_table as a private dispatch table.

예를 들면

f = io.BytesIO()
p = pickle.Pickler(f)
p.dispatch_table = copyreg.dispatch_table.copy()
p.dispatch_table[SomeClass] = reduce_SomeClass

는 SomeClass 클래스를 특별히 처리하는 사설 디스패치 테이블을 갖는 pickle.Pickler 의 인스턴스를 생성합니다. 또는, 코드

class MyPickler(pickle.Pickler):
    dispatch_table = copyreg.dispatch_table.copy()
    dispatch_table[SomeClass] = reduce_SomeClass
f = io.BytesIO()
p = MyPickler(f)

does the same but all instances of MyPickler will by default share the private dispatch table. On the other hand, the code

copyreg.pickle(SomeClass, reduce_SomeClass)
f = io.BytesIO()
p = pickle.Pickler(f)

modifies the global dispatch table shared by all users of the copyreg module.

상태 저장 객체 처리

Here’s an example that shows how to modify pickling behavior for a class. The TextReader class below opens a text file, and returns the line number and line contents each time its readline() method is called. If a TextReader instance is pickled, all attributes except the file object member are saved. When the instance is unpickled, the file is reopened, and reading resumes from the last location. The __setstate__() and __getstate__() methods are used to implement this behavior.

class TextReader:
    """Print and number lines in a text file."""

    def __init__(self, filename):
        self.filename = filename
        self.file = open(filename)
        self.lineno = 0

    def readline(self):
        self.lineno += 1
        line = self.file.readline()
        if not line:
            return None
        if line.endswith('\n'):
            line = line[:-1]
        return "%i: %s" % (self.lineno, line)

    def __getstate__(self):
        # Copy the object's state from self.__dict__ which contains
        # all our instance attributes. Always use the dict.copy()
        # method to avoid modifying the original state.
        state = self.__dict__.copy()
        # Remove the unpicklable entries.
        del state['file']
        return state

    def __setstate__(self, state):
        # Restore instance attributes (i.e., filename and lineno).
        self.__dict__.update(state)
        # Restore the previously opened file's state. To do so, we need to
        # reopen it and read from it until the line count is restored.
        file = open(self.filename)
        for _ in range(self.lineno):
            file.readline()
        # Finally, save the file.
        self.file = file

사용 예는 다음과 같은 식입니다:

>>> reader = TextReader("hello.txt")
>>> reader.readline()
'1: Hello world!'
>>> reader.readline()
'2: I am line number two.'
>>> new_reader = pickle.loads(pickle.dumps(reader))
>>> new_reader.readline()
'3: Goodbye!'

형, 함수 및 기타 객체에 대한 사용자 정의 환원

Added in version 3.8.

때로, dispatch_table이 충분히 유연하지 않을 수 있습니다. 특히 객체의 형이 아닌 다른 기준에 따라 피클링을 사용자 정의하거나, 함수와 클래스 피클링을 사용자 정의하고 싶을 수 있습니다.

For those cases, it is possible to subclass from the Pickler class and implement a reducer_override() method. This method can return an arbitrary reduction tuple (see __reduce__()). It can alternatively return NotImplemented to fallback to the traditional behavior.

dispatch_table과 reducer_override()가 모두 정의되면, reducer_override() 메서드가 우선합니다.

참고

성능상의 이유로, 다음과 같은 객체에 대해서는 reducer_override()가 호출되지 않을 수 있습니다: None, True, False 및 int, float, bytes, str, dict, set, frozenset, list 및 tuple의 정확한(exact) 인스턴스.

다음은 주어진 클래스를 피클링하고 재구성할 수 있도록 하는 간단한 예제입니다:

import io
import pickle

class MyClass:
    my_attribute = 1

class MyPickler(pickle.Pickler):
    def reducer_override(self, obj):
        """Custom reducer for MyClass."""
        if getattr(obj, "__name__", None) == "MyClass":
            return type, (obj.__name__, obj.__bases__,
                          {'my_attribute': obj.my_attribute})
        else:
            # For any other object, fallback to usual reduction
            return NotImplemented

f = io.BytesIO()
p = MyPickler(f)
p.dump(MyClass)

del MyClass

unpickled_class = pickle.loads(f.getvalue())

assert isinstance(unpickled_class, type)
assert unpickled_class.__name__ == "MyClass"
assert unpickled_class.my_attribute == 1

아웃 오브 밴드 버퍼

Added in version 3.8.

일부 상황에서는, pickle 모듈을 사용하여 많은 양의 데이터를 전송합니다. 따라서 성능과 자원 소비를 보존하기 위해 메모리 복사 횟수를 최소화하는 것이 중요할 수 있습니다. 그러나, pickle 모듈의 정상적인 작동은, 객체의 그래프(graph)적인 구조를 순차적인 바이트 스트림으로 변환하기 때문에, 본질적으로 피클 스트림과의 데이터 복사를 수반합니다.

제공자(provider)(전송될 객체 형의 구현)와 소비자(consumer)(통신 시스템의 구현)가 모두 피클 프로토콜 5 이상에서 제공되는 아웃 오브 밴드 전송 기능을 지원하면 이 제약 조건을 피할 수 있습니다.

제공자 API

The large data objects to be pickled must implement a __reduce_ex__() method specialized for protocol 5 and higher, which returns a PickleBuffer instance (instead of e.g. a bytes object) for any large data.

PickleBuffer 객체는 하부 버퍼가 아웃 오브 밴드 전송 대상이라는 신호를 보냅니다. 이러한 객체는 pickle 모듈의 일반적인 사용과 호환됩니다. 그러나, 소비자는 pickle에게 그 버퍼를 스스로 처리하겠다고 알릴 수도 있습니다.

소비자 API

통신 시스템은 객체 그래프를 직렬화할 때 생성된 PickleBuffer 객체의 사용자 정의 처리를 활성화할 수 있습니다.

송신 측에서는, buffer_callback 인자를 Pickler (또는 dump()나 dumps() 함수)에 전달해야 합니다. 이 인자는 객체 그래프를 피클링할 때 생성된 각 PickleBuffer로 호출됩니다. buffer_callback에 의해 누적된 버퍼는 피클 스트림으로 복사되지 않고, 저렴한 마커만 삽입됩니다.

수신 측에서는, buffer_callback에 전달된 버퍼의 이터러블인 buffers 인자를 Unpickler (또는 load()나 loads() 함수)에 전달해야 합니다. 그 이터러블은 buffer_callback에 전달된 것과 같은 순서로 버퍼를 만들어야 합니다. 이러한 버퍼는 피클링이 원래 PickleBuffer 객체를 생성한 객체의 재구성자가 기대하는 데이터를 제공합니다.

송신 측과 수신 측 사이에서, 통신 시스템은 아웃 오브 밴드 버퍼를 위한 자체 전송 메커니즘을 자유롭게 구현할 수 있습니다. 잠재적인 최적화에는 공유 메모리나 데이터 유형에 따른 압축이 포함됩니다.

예제

다음은 아웃 오브 버퍼 피클링에 참여할 수 있는 bytearray 서브 클래스를 구현하는 간단한 예제입니다:

class ZeroCopyByteArray(bytearray):

    def __reduce_ex__(self, protocol):
        if protocol >= 5:
            return type(self)._reconstruct, (PickleBuffer(self),), None
        else:
            # PickleBuffer is forbidden with pickle protocols <= 4.
            return type(self)._reconstruct, (bytearray(self),)

    @classmethod
    def _reconstruct(cls, obj):
        with memoryview(obj) as m:
            # Get a handle over the original buffer object
            obj = m.obj
            if type(obj) is cls:
                # Original buffer object is a ZeroCopyByteArray, return it
                # as-is.
                return obj
            else:
                return cls(obj)

재구성자(_reconstruct 클래스 메서드)는 올바른 형이면 버퍼를 제공하는 객체를 반환합니다. 이것은 이 장난감 예제에서 제로-복사 동작을 흉내 내는 손쉬운 방법입니다.

소비자 측에서는, 그 객체들을 일반적인 방법으로 피클 할 수 있습니다. 역 직렬화될 때 원래 객체의 사본을 제공합니다:

b = ZeroCopyByteArray(b"abc")
data = pickle.dumps(b, protocol=5)
new_b = pickle.loads(data)
print(b == new_b)  # True
print(b is new_b)  # False: a copy was made

그러나 buffer_callback을 전달하고 역 직렬화할 때 누적된 버퍼를 돌려주면, 원래의 객체를 다시 얻을 수 있습니다:

b = ZeroCopyByteArray(b"abc")
buffers = []
data = pickle.dumps(b, protocol=5, buffer_callback=buffers.append)
new_b = pickle.loads(data, buffers=buffers)
print(b == new_b)  # True
print(b is new_b)  # True: no copy was made

이 예제는 bytearray가 자체 메모리를 할당한다는 사실로 인해 제한됩니다: 즉, 다른 객체의 메모리를 사용하는 bytearray 인스턴스를 만들 수 없습니다. 그러나, NumPy 배열과 같은 제삼자 데이터형에는 이러한 제한이 없으며, 별개의 프로세스나 시스템 간에 전송할 때 제로-복사 피클링(또는 최소한의 복사)을 사용할 수 있습니다.

더 보기

PEP 574 [https://peps.python.org/pep-0574/] – 아웃 오브 밴드 데이터를 포함하는 피클 프로토콜 5

전역 제한하기

기본적으로, 역 피클링은 피클 데이터에서 찾은 모든 클래스나 함수를 임포트 합니다. 많은 응용 프로그램에서는, 역 피클러가 임의 코드를 임포트하고 호출할 수 있으므로, 이 동작을 받아들일 수 없습니다. 이 손으로 만든 피클 데이터 스트림이 로드될 때 하는 일을 생각해보십시오:

>>> import pickle
>>> pickle.loads(b"cos\nsystem\n(S'echo hello world'\ntR.")
hello world
0

이 예제에서, 역 피클러는 os.system() 함수를 임포트하고 문자열 인자 “echo hello world”를 적용합니다. 이 예제가 공격적이지는 않지만, 어떤 것들은 시스템을 손상할 수 있다고 상상하기 어렵지 않습니다.

이런 이유로, 여러분은 Unpickler.find_class()를 사용자 정의하여 언 피클 되는 것을 제어하고 싶을 수 있습니다. 이름이 제안하는 것과는 달리, Unpickler.find_class() 는 전역(즉, 클래스나 함수)이 요청될 때마다 호출됩니다. 따라서 전역을 완전히 금지하거나 안전한 부분집합으로 제한할 수 있습니다.

다음은 builtins 모듈에서 몇 가지 안전한 클래스만 로드되도록 허용하는 역 피클러의 예입니다:

import builtins
import io
import pickle

safe_builtins = {
    'range',
    'complex',
    'set',
    'frozenset',
    'slice',
}

class RestrictedUnpickler(pickle.Unpickler):

    def find_class(self, module, name):
        # Only allow safe classes from builtins.
        if module == "builtins" and name in safe_builtins:
            return getattr(builtins, name)
        # Forbid everything else.
        raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
                                     (module, name))

def restricted_loads(s):
    """Helper function analogous to pickle.loads()."""
    return RestrictedUnpickler(io.BytesIO(s)).load()

A sample usage of our unpickler working as intended:

>>> restricted_loads(pickle.dumps([1, 2, range(15)]))
[1, 2, range(0, 15)]
>>> restricted_loads(b"cos\nsystem\n(S'echo hello world'\ntR.")
Traceback (most recent call last):
  ...
pickle.UnpicklingError: global 'os.system' is forbidden
>>> restricted_loads(b'cbuiltins\neval\n'
...                  b'(S\'getattr(__import__("os"), "system")'
...                  b'("echo hello world")\'\ntR.')
Traceback (most recent call last):
  ...
pickle.UnpicklingError: global 'builtins.eval' is forbidden

예를 통해 알 수 있듯이, 역 피클을 허락하는 것에 주의를 기울여야 합니다. 따라서 보안이 중요하다면, xmlrpc.client 나 제삼자 솔루션의 마샬링 API 같은 대안을 고려할 수 있습니다.

성능

최신 버전의 피클 프로토콜(프로토콜 2 이상)은 몇 가지 공통 기능 및 내장형에 대한 효율적인 바이너리 인코딩을 제공합니다. 또한, pickle 모듈은 C로 작성된 투명한 최적화기를 가지고 있습니다.

예제

가장 간단한 코드로, dump()와 load() 함수를 사용하십시오.

import pickle

# An arbitrary collection of objects supported by pickle.
data = {
    'a': [1, 2.0, 3+4j],
    'b': ("character string", b"byte string"),
    'c': {None, True, False}
}

with open('data.pickle', 'wb') as f:
    # Pickle the 'data' dictionary using the highest protocol available.
    pickle.dump(data, f, pickle.HIGHEST_PROTOCOL)

다음 예제는 결과로 나온 피클 데이터를 읽습니다.

import pickle

with open('data.pickle', 'rb') as f:
    # The protocol version used is detected automatically, so we do not
    # have to specify it.
    data = pickle.load(f)

더 보기

모듈 copyreg

확장형에 대한 피클 인터페이스 생성자 등록

모듈 pickletools

피클 된 데이터로 작업하고 분석하는 도구.

모듈 shelve

객체의 인덱싱 된 데이터베이스; pickle을 사용합니다.

모듈 copy

얕거나 깊은 객체 복사.

모듈 marshal

내장형의 고성능 직렬화.

각주

[1]

이것을 marshal 모듈과 혼동하지 마십시오.

[2]

이것이 lambda 함수가 pickle 될 수 없는 이유입니다: 모든 lambda 함수는 같은 이름을 공유합니다: <lambda>.

[3]

발생하는 예외는 ImportError 나 AttributeError 일 가능성이 크지만, 그 밖의 다른 것일 수 있습니다.

[4]

copy 모듈은 얕거나 깊은 복사 연산에 이 프로토콜을 사용합니다.

[5]

The limitation on alphanumeric characters is due to the fact that persistent IDs in protocol 0 are delimited by the newline character. Therefore if any kind of newline characters occurs in persistent IDs, the resulting pickled data will become unreadable.

copyreg — Register pickle support functions

소스 코드: Lib/copyreg.py [https://github.com/python/cpython/tree/main/Lib/copyreg.py]

copyreg 모듈은 특정 객체를 피클 하는 동안 사용되는 함수를 정의하는 방법을 제공합니다. pickle과 copy 모듈은 해당 객체를 피클/복사할 때 이 함수를 사용합니다. 이 모듈은 클래스가 아닌 객체 생성자에 대한 구성 정보를 제공합니다. 이러한 생성자는 팩토리 함수나 클래스 인스턴스일 수 있습니다.

copyreg.constructor(object)

object를 유효한 생성자로 선언합니다. object가 콜러블이 아니면 (따라서 생성자로 유효하지 않으면), TypeError가 발생합니다.

copyreg.pickle(type, function, constructor_ob=None)

Declares that function should be used as a “reduction” function for objects of type type. function must return either a string or a tuple containing between two and six elements. See the dispatch_table for more details on the interface of function.

The constructor_ob parameter is a legacy feature and is now ignored, but if passed it must be a callable.

Note that the dispatch_table attribute of a pickler object or subclass of pickle.Pickler can also be used for declaring reduction functions.

예제

아래 예제는 피클 함수를 등록하는 방법과 사용법을 보여줍니다.:

>>> import copyreg, copy, pickle
>>> class C:
...     def __init__(self, a):
...         self.a = a
...
>>> def pickle_c(c):
...     print("pickling a C instance...")
...     return C, (c.a,)
...
>>> copyreg.pickle(C, pickle_c)
>>> c = C(1)
>>> d = copy.copy(c)
pickling a C instance...
>>> p = pickle.dumps(c)
pickling a C instance...

shelve — Python object persistence

소스 코드: Lib/shelve.py [https://github.com/python/cpython/tree/main/Lib/shelve.py]

“쉘프(shelf)”는 영속적인(persistent) 딕셔너리류 객체입니다. “dbm” 데이터베이스와의 차이점은 쉘프의 값(키가 아닙니다!)이 사실상 임의의 파이썬 객체일 수 있다는 것입니다 — pickle 모듈에서 처리할 수 있는 모든 것입니다. 여기에는 대부분의 클래스 인스턴스, 재귀적 데이터형 및 많은 공유 서브 객체를 포함하는 객체가 포함됩니다. 키는 일반 문자열입니다.

shelve.open(filename, flag='c', protocol=None, writeback=False)

영속적 딕셔너리를 엽니다. 지정된 filename은 하부 데이터베이스의 기본 파일명입니다. 부작용으로, 확장명이 파일명에 추가될 수 있으며 여러 개의 파일이 만들어질 수 있습니다. 기본적으로, 하부 데이터베이스 파일은 읽기와 쓰기 용으로 열립니다. 선택적 flag 매개 변수는 dbm.open()의 flag 매개 변수와 같게 해석됩니다.

By default, pickles created with pickle.DEFAULT_PROTOCOL are used to serialize values. The version of the pickle protocol can be specified with the protocol parameter.

파이썬 의미론 때문에, 쉘프는 가변 영속 딕셔너리 항목이 언제 수정되는지 알 수 없습니다. 기본적으로 수정된 객체는 쉘프에 대입될 때만 기록됩니다 (예제를 참조하십시오). 선택적인 writeback 매개 변수가 True로 설정되면, 액세스 된 모든 항목도 메모리에 캐시 되고, sync()와 close()가 호출될 때 다시 기록됩니다; 이것은 영속 딕셔너리의 가변 항목을 변경하는 것을 더 수월하게 만들지만, 많은 항목이 액세스 되면, 캐시를 위해 막대한 양의 메모리를 소비할 수 있으며, 액세스 된 모든 항목을 다시 기록하기 때문에 닫기 연산이 매우 느려질 수 있습니다 (어떤 액세스 된 항목이 가변인지, 어떤 것이 실제로 변경되었는지를 판별할 방법이 없습니다).

버전 3.10에서 변경: pickle.DEFAULT_PROTOCOL is now used as the default pickle protocol.

버전 3.11에서 변경: Accepts path-like object for filename.

참고

쉘프가 자동으로 닫히는 것에 의지하지 마십시오; 더는 필요 없을 때 close()를 명시적으로 호출하거나, shelve.open()을 컨텍스트 관리자로 사용하십시오:

with shelve.open('spam') as db:
    db['eggs'] = 'eggs'

경고

shelve 모듈은 pickle로 뒷받침되기 때문에, 신뢰할 수 없는 소스에서 쉘프를 로드하는 것은 안전하지 않습니다. 피클과 마찬가지로, 쉘프를 로드하면 임의의 코드를 실행할 수 있습니다.

Shelf objects support most of methods and operations supported by dictionaries (except copying, constructors and operators | and |=). This eases the transition from dictionary based scripts to those requiring persistent storage.

두 가지 추가 메서드가 지원됩니다:

Shelf.sync()

writeback을 True로 설정하여 쉘프를 열었으면, 캐시의 모든 항목을 다시 기록합니다. 또한, 적절하다면, 캐시를 비우고 디스크 상의 영속 딕셔너리를 동기화합니다. close()로 쉘프를 닫을 때 자동으로 호출됩니다.

Shelf.close()

영구 딕셔너리 객체를 동기화하고 닫습니다. 닫힌 쉘프에 대한 연산은 ValueError로 실패합니다.

더 보기

Persistent dictionary recipe [https://code.activestate.com/recipes/576642-persistent-dict-with-multiple-standard-file-format/] with widely supported storage formats and having the speed of native dictionaries.

제약 사항

사용되는 데이터베이스 패키지의 선택(가령 dbm.ndbm이나 dbm.gnu)은 어떤 인터페이스가 사용 가능한지에 따라 다릅니다. 따라서 dbm을 사용하여 데이터베이스를 직접 여는 것은 안전하지 않습니다. 또한, 데이터베이스는 (불행히도) dbm이 사용된다면 그것의 제약이 적용됩니다 — 이것은 데이터베이스에 저장되는 객체(의 피클 된 표현이)가 상당히 작아야 하며, 드물긴 하지만 키 충돌로 인해 데이터베이스가 업데이트를 거부할 수 있음을 뜻합니다.

shelve 모듈은 쉘브된 객체에 대한 동시성(concurrent) 읽기/쓰기 액세스를 지원하지 않습니다. (여러 동시적인 읽기 액세스는 안전합니다.) 어떤 프로그램이 쓰기 용으로 쉘프를 열고 있으면, 다른 어떤 프로그램도 읽기나 쓰기 용으로 열지 않아야 합니다. 유닉스 파일 잠금을 이 문제를 해결하는 데 사용할 수 있지만, 이것은 유닉스 버전마다 다르며 사용된 데이터베이스 구현에 대한 지식이 필요합니다.

On macOS dbm.ndbm can silently corrupt the database file on updates, which can cause hard crashes when trying to read from the database.

class shelve.Shelf(dict, protocol=None, writeback=False, keyencoding='utf-8')

dict 객체에 피클 된 값을 저장하는 collections.abc.MutableMapping의 서브 클래스.

By default, pickles created with pickle.DEFAULT_PROTOCOL are used to serialize values. The version of the pickle protocol can be specified with the protocol parameter. See the pickle documentation for a discussion of the pickle protocols.

writeback 매개 변수가 True이면, 객체는 액세스 된 모든 항목의 캐시를 보유하고 sync와 close 할 때 dict에 다시 씁니다. 이것은 가변 항목에 대한 자연스러운 연산을 허락하지만, 더 많은 메모리를 소비하고 sync와 close 연산이 오래 걸릴 수 있습니다.

keyencoding 매개 변수는 하부 dict에 사용되기 전에 키를 인코딩하는 데 사용되는 인코딩입니다.

Shelf 객체는 컨텍스트 관리자로 사용할 수도 있습니다. 이 경우 with 블록이 끝날 때 자동으로 닫힙니다.

버전 3.2에서 변경: keyencoding 매개 변수가 추가되었습니다; 이전에는 키가 항상 UTF-8으로 인코딩되었습니다.

버전 3.4에서 변경: 컨텍스트 관리자 지원 추가.

버전 3.10에서 변경: pickle.DEFAULT_PROTOCOL is now used as the default pickle protocol.

class shelve.BsdDbShelf(dict, protocol=None, writeback=False, keyencoding='utf-8')

A subclass of Shelf which exposes first(), next(), previous(), last() and set_location() methods. These are available in the third-party bsddb module from pybsddb [https://www.jcea.es/programacion/pybsddb.htm] but not in other database modules. The dict object passed to the constructor must support those methods. This is generally accomplished by calling one of bsddb.hashopen(), bsddb.btopen() or bsddb.rnopen(). The optional protocol, writeback, and keyencoding parameters have the same interpretation as for the Shelf class.

class shelve.DbfilenameShelf(filename, flag='c', protocol=None, writeback=False)

딕셔너리류 객체 대신에 filename을 받아들이는 Shelf의 서브 클래스. 하부 파일은 dbm.open()을 사용하여 열립니다. 기본적으로, 파일은 읽기와 쓰기가 가능하도록 만들어지고 열립니다. 선택적 flag 매개 변수는 open() 기능과 같게 해석됩니다. 선택적 protocol과 writeback 매개 변수는 Shelf 클래스와 같게 해석됩니다.

예제

인터페이스를 요약하면 (key는 문자열입니다, data는 임의의 객체입니다):

import shelve

d = shelve.open(filename)  # open -- file may get suffix added by low-level
                           # library

d[key] = data              # store data at key (overwrites old data if
                           # using an existing key)
data = d[key]              # retrieve a COPY of data at key (raise KeyError
                           # if no such key)
del d[key]                 # delete data stored at key (raises KeyError
                           # if no such key)

flag = key in d            # true if the key exists
klist = list(d.keys())     # a list of all existing keys (slow!)

# as d was opened WITHOUT writeback=True, beware:
d['xx'] = [0, 1, 2]        # this works as expected, but...
d['xx'].append(3)          # *this doesn't!* -- d['xx'] is STILL [0, 1, 2]!

# having opened d without writeback=True, you need to code carefully:
temp = d['xx']             # extracts the copy
temp.append(5)             # mutates the copy
d['xx'] = temp             # stores the copy right back, to persist it

# or, d=shelve.open(filename,writeback=True) would let you just code
# d['xx'].append(5) and have it work as expected, BUT it would also
# consume more memory and make the d.close() operation slower.

d.close()                  # close it

더 보기

모듈 dbm

dbm 스타일 데이터베이스에 대한 범용 인터페이스.

모듈 pickle

shelve에 의해 사용되는 객체 직렬화.

marshal — Internal Python object serialization

This module contains functions that can read and write Python values in a binary format. The format is specific to Python, but independent of machine architecture issues (e.g., you can write a Python value to a file on a PC, transport the file to a Mac, and read it back there). Details of the format are undocumented on purpose; it may change between Python versions (although it rarely does). [1]

This is not a general “persistence” module. For general persistence and transfer of Python objects through RPC calls, see the modules pickle and shelve. The marshal module exists mainly to support reading and writing the “pseudo-compiled” code for Python modules of .pyc files. Therefore, the Python maintainers reserve the right to modify the marshal format in backward incompatible ways should the need arise. The format of code objects is not compatible between Python versions, even if the version of the format is the same. De-serializing a code object in the incorrect Python version has undefined behavior. If you’re serializing and de-serializing Python objects, use the pickle module instead – the performance is comparable, version independence is guaranteed, and pickle supports a substantially wider range of objects than marshal.

경고

marshal 모듈은 잘못되었거나 악의적으로 구성된 데이터에 대해 보안성을 갖추려는 것이 아닙니다. 신뢰할 수 없거나 인증되지 않은 출처에서 받은 데이터를 역 마샬 하지 마십시오.

파일을 읽고 쓰는 함수는 물론 바이트열류 객체에서 작동하는 함수도 있습니다.

Not all Python object types are supported; in general, only objects whose value is independent from a particular invocation of Python can be written and read by this module. The following types are supported:

Numeric types: int, bool, float, complex.

Strings (str) and bytes. Bytes-like objects like bytearray are marshalled as bytes.

Containers: tuple, list, set, frozenset, and (since version 5), slice. It should be understood that these are supported only if the values contained therein are themselves supported. Recursive containers are supported since version 3.

The singletons None, Ellipsis and StopIteration.

code objects, if allow_code is true. See note above about version dependence.

버전 3.4에서 변경:

Added format version 3, which supports marshalling recursive lists, sets and dictionaries.

Added format version 4, which supports efficient representations of short strings.

버전 3.14에서 변경: Added format version 5, which allows marshalling slices.

모듈은 다음 함수를 정의합니다:

marshal.dump(value, file, version=version, /, *, allow_code=True)

열린 파일에 값을 기록합니다. value는 지원되는 형이어야 합니다. 파일은 쓰기 가능한 바이너리 파일 이어야 합니다.

If the value has (or contains an object that has) an unsupported type, a ValueError exception is raised — but garbage data will also be written to the file. The object will not be properly read back by load(). Code objects are only supported if allow_code is true.

version 인자는 dump가 사용해야 하는 데이터 형식을 나타냅니다 (아래를 참조하십시오).

Raises an auditing event marshal.dumps with arguments value, version.

버전 3.13에서 변경: Added the allow_code parameter.

marshal.load(file, /, *, allow_code=True)

Read one value from the open file and return it. If no valid value is read (e.g. because the data has a different Python version’s incompatible marshal format), raise EOFError, ValueError or TypeError. Code objects are only supported if allow_code is true. The file must be a readable binary file.

Raises an auditing event marshal.load with no arguments.

참고

지원하지 않는 형을 포함하는 객체가 dump()로 마샬 되었으면, load()는 역 마샬이 불가능한 형을 None으로 치환합니다.

버전 3.10에서 변경: This call used to raise a code.__new__ audit event for each code object. Now it raises a single marshal.load event for the entire load operation.

버전 3.13에서 변경: Added the allow_code parameter.

marshal.dumps(value, version=version, /, *, allow_code=True)

Return the bytes object that would be written to a file by dump(value, file). The value must be a supported type. Raise a ValueError exception if value has (or contains an object that has) an unsupported type. Code objects are only supported if allow_code is true.

version 인자는 dumps가 사용해야 하는 데이터 형식을 나타냅니다 (아래를 참조하십시오).

Raises an auditing event marshal.dumps with arguments value, version.

버전 3.13에서 변경: Added the allow_code parameter.

marshal.loads(bytes, /, *, allow_code=True)

Convert the bytes-like object to a value. If no valid value is found, raise EOFError, ValueError or TypeError. Code objects are only supported if allow_code is true. Extra bytes in the input are ignored.

Raises an auditing event marshal.loads with argument bytes.

버전 3.10에서 변경: This call used to raise a code.__new__ audit event for each code object. Now it raises a single marshal.loads event for the entire load operation.

버전 3.13에서 변경: Added the allow_code parameter.

또한, 다음 상수가 정의됩니다:

marshal.version

Indicates the format that the module uses. Version 0 is the historical first version; subsequent versions add new features. Generally, a new version becomes the default when it is introduced.

Version

Available since

New features

1

Python 2.4

Sharing interned strings

2

Python 2.5

Binary representation of floats

3

Python 3.4

Support for object instancing and recursion

4

Python 3.4

Efficient representation of short strings

5

Python 3.14

Support for slice objects

각주

[1]

이 모듈의 이름은 (다른 것 중에서도) Modula-3의 설계자가 사용하는 약간의 용어에서 유래합니다. 이들은 자급적(self-contained) 형식으로 데이터를 전달하는 데 “마샬링(marshalling)”이라는 용어를 사용합니다. 엄밀히 말하면, “마샬”은 내부의 어떤 데이터를 외부 형식(예를 들어 RPC 버퍼에)으로 변환하는 것을, “역 마샬”은 그 반대 절차를 뜻합니다.

dbm — Interfaces to Unix “databases”

소스 코드: Lib/dbm/__init__.py [https://github.com/python/cpython/tree/main/Lib/dbm/__init__.py]

dbm is a generic interface to variants of the DBM database:

dbm.sqlite3

dbm.gnu

dbm.ndbm

If none of these modules are installed, the slow-but-simple implementation in module dbm.dumb will be used. There is a third party interface [https://www.jcea.es/programacion/pybsddb.htm] to the Oracle Berkeley DB.

exception dbm.error

지원되는 각 모듈에 의해 발생할 수 있는 예외를 포함하는 튜플. 역시 dbm.error라고 이름 붙인 고유한 예외를 첫 번째 항목으로 갖고 있습니다 — dbm.error가 발생할 때 이것이 사용됩니다.

dbm.whichdb(filename)

This function attempts to guess which of the several simple database modules available — dbm.sqlite3, dbm.gnu, dbm.ndbm, or dbm.dumb — should be used to open a given file.

Return one of the following values:

None if the file can’t be opened because it’s unreadable or doesn’t exist

the empty string ('') if the file’s format can’t be guessed

a string containing the required module name, such as 'dbm.ndbm' or 'dbm.gnu'

버전 3.11에서 변경: filename accepts a path-like object.

dbm.open(file, flag='r', mode=0o666)

Open a database and return the corresponding database object.

매개변수:

file (path-like object) –

The database file to open.

If the database file already exists, the whichdb() function is used to determine its type and the appropriate module is used; if it does not exist, the first submodule listed above that can be imported is used.

flag (str) –

'r' (default): Open existing database for reading only.

'w': Open existing database for reading and writing.

'c': Open database for reading and writing, creating it if it doesn’t exist.

'n': Always create a new, empty database, open for reading and writing.

mode (int) – The Unix file access mode of the file (default: octal 0o666), used only when the database has to be created.

버전 3.11에서 변경: file accepts a path-like object.

The object returned by open() supports the same basic functionality as a dict; keys and their corresponding values can be stored, retrieved, and deleted, and the in operator and the keys() method are available, as well as get() and setdefault() methods.

Key and values are always stored as bytes. This means that when strings are used they are implicitly converted to the default encoding before being stored.

이 객체는 with 문에서도 사용되도록 지원해서, 완료될 때 자동으로 닫힙니다.

버전 3.2에서 변경: get() and setdefault() methods are now available for all dbm backends.

버전 3.4에서 변경: Added native support for the context management protocol to the objects returned by open().

버전 3.8에서 변경: Deleting a key from a read-only database raises a database module specific exception instead of KeyError.

다음 예제는 일부 호스트 명과 해당 제목을 기록한 다음, 데이터베이스의 내용을 인쇄합니다:

import dbm

# Open database, creating it if necessary.
with dbm.open('cache', 'c') as db:

    # Record some values
    db[b'hello'] = b'there'
    db['www.python.org'] = 'Python Website'
    db['www.cnn.com'] = 'Cable News Network'

    # Note that the keys are considered bytes now.
    assert db[b'www.python.org'] == b'Python Website'
    # Notice how the value is now in bytes.
    assert db['www.cnn.com'] == b'Cable News Network'

    # Often-used methods of the dict interface work too.
    print(db.get('python.org', b'not present'))

    # Storing a non-string key or value will raise an exception (most
    # likely a TypeError).
    db['www.yahoo.com'] = 4

# db is automatically closed when leaving the with statement.

더 보기

모듈 shelve

문자열이 아닌 데이터를 저장하는 지속성 모듈.

개별 서브 모듈은 다음 섹션에서 설명합니다.

dbm.sqlite3 — SQLite backend for dbm

Added in version 3.13.

Source code: Lib/dbm/sqlite3.py [https://github.com/python/cpython/tree/main/Lib/dbm/sqlite3.py]

This module uses the standard library sqlite3 module to provide an SQLite backend for the dbm module. The files created by dbm.sqlite3 can thus be opened by sqlite3, or any other SQLite browser, including the SQLite CLI.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

dbm.sqlite3.open(filename, /, flag='r', mode=0o666)

Open an SQLite database. The returned object behaves like a mapping, implements a close() method, and supports a “closing” context manager via the with keyword.

매개변수:

filename (path-like object) – The path to the database to be opened.

flag (str) –

'r' (default): Open existing database for reading only.

'w': Open existing database for reading and writing.

'c': Open database for reading and writing, creating it if it doesn’t exist.

'n': Always create a new, empty database, open for reading and writing.

mode – The Unix file access mode of the file (default: octal 0o666), used only when the database has to be created.

dbm.gnu — GNU database manager

소스 코드: Lib/dbm/gnu.py [https://github.com/python/cpython/tree/main/Lib/dbm/gnu.py]

The dbm.gnu module provides an interface to the GDBM library, similar to the dbm.ndbm module, but with additional functionality like crash tolerance.

참고

The file formats created by dbm.gnu and dbm.ndbm are incompatible and can not be used interchangeably.

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

exception dbm.gnu.error

I/O 에러와 같은 dbm.gnu 특정 에러에서 발생합니다. 잘못된 키 지정과 같은 일반적인 매핑 에러에 대해서는 KeyError가 발생합니다.

dbm.gnu.open(filename, flag='r', mode=0o666, /)

Open a GDBM database and return a gdbm object.

매개변수:

filename (path-like object) – The database file to open.

flag (str) –

'r' (default): Open existing database for reading only.

'w': Open existing database for reading and writing.

'c': Open database for reading and writing, creating it if it doesn’t exist.

'n': Always create a new, empty database, open for reading and writing.

The following additional characters may be appended to control how the database is opened:

'f': Open the database in fast mode. Writes to the database will not be synchronized.

's': Synchronized mode. Changes to the database will be written immediately to the file.

'u': Do not lock database.

Not all flags are valid for all versions of GDBM. See the open_flags member for a list of supported flag characters.

mode (int) – The Unix file access mode of the file (default: octal 0o666), used only when the database has to be created.

예외 발생:

error – If an invalid flag argument is passed.

버전 3.11에서 변경: filename accepts a path-like object.

dbm.gnu.open_flags

A string of characters the flag parameter of open() supports.

gdbm objects behave similar to mappings, but items() and values() methods are not supported. The following methods are also provided:

gdbm.firstkey()

It’s possible to loop over every key in the database using this method and the nextkey() method. The traversal is ordered by GDBM’s internal hash values, and won’t be sorted by the key values. This method returns the starting key.

gdbm.nextkey(key)

순회에서 key 뒤에 오는 키를 반환합니다. 다음 코드는 메모리에 모든 키를 포함하는 리스트를 만들지 않고, 데이터베이스 db의 모든 키를 인쇄합니다:

k = db.firstkey()
while k is not None:
    print(k)
    k = db.nextkey(k)

gdbm.reorganize()

If you have carried out a lot of deletions and would like to shrink the space used by the GDBM file, this routine will reorganize the database. gdbm objects will not shorten the length of a database file except by using this reorganization; otherwise, deleted file space will be kept and reused as new (key, value) pairs are added.

gdbm.sync()

데이터베이스가 빠른 모드로 열렸을 때, 이 메서드를 사용하면 기록되지 않은 데이터가 디스크에 기록됩니다.

gdbm.close()

Close the GDBM database.

gdbm.clear()

Remove all items from the GDBM database.

Added in version 3.13.

dbm.ndbm — New Database Manager

소스 코드: Lib/dbm/ndbm.py [https://github.com/python/cpython/tree/main/Lib/dbm/ndbm.py]

The dbm.ndbm module provides an interface to the NDBM library. This module can be used with the “classic” NDBM interface or the GDBM compatibility interface.

참고

The file formats created by dbm.gnu and dbm.ndbm are incompatible and can not be used interchangeably.

경고

The NDBM library shipped as part of macOS has an undocumented limitation on the size of values, which can result in corrupted database files when storing values larger than this limit. Reading such corrupted files can result in a hard crash (segmentation fault).

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

exception dbm.ndbm.error

I/O 에러와 같은 dbm.ndbm 특정 에러에서 발생합니다. 잘못된 키 지정과 같은 일반적인 매핑 에러에 대해서는 KeyError가 발생합니다.

dbm.ndbm.library

Name of the NDBM implementation library used.

dbm.ndbm.open(filename, flag='r', mode=0o666, /)

Open an NDBM database and return an ndbm object.

매개변수:

filename (path-like object) – The basename of the database file (without the .dir or .pag extensions).

flag (str) –

'r' (default): Open existing database for reading only.

'w': Open existing database for reading and writing.

'c': Open database for reading and writing, creating it if it doesn’t exist.

'n': Always create a new, empty database, open for reading and writing.

mode (int) – The Unix file access mode of the file (default: octal 0o666), used only when the database has to be created.

ndbm objects behave similar to mappings, but items() and values() methods are not supported. The following methods are also provided:

버전 3.11에서 변경: Accepts path-like object for filename.

ndbm.close()

Close the NDBM database.

ndbm.clear()

Remove all items from the NDBM database.

Added in version 3.13.

dbm.dumb — 이식성 있는 DBM 구현

소스 코드: Lib/dbm/dumb.py [https://github.com/python/cpython/tree/main/Lib/dbm/dumb.py]

참고

dbm.dumb 모듈은 더욱 강인한 모듈을 사용할 수 없을 때 dbm 모듈에 대한 최후의 대체 폴백으로 사용됩니다. dbm.dumb 모듈은 속도를 위해 작성되지 않았으며 다른 데이터베이스 모듈만큼 많이 사용되지는 않습니다.

The dbm.dumb module provides a persistent dict-like interface which is written entirely in Python. Unlike other dbm backends, such as dbm.gnu, no external library is required.

The dbm.dumb module defines the following:

exception dbm.dumb.error

I/O 에러와 같은 dbm.dumb 특정 에러에서 발생합니다. 잘못된 키 지정과 같은 일반적인 매핑 에러에 대해서는 KeyError가 발생합니다.

dbm.dumb.open(filename, flag='c', mode=0o666)

Open a dbm.dumb database. The returned database object behaves similar to a mapping, in addition to providing sync() and close() methods.

매개변수:

filename –

The basename of the database file (without extensions). A new database creates the following files:

filename.dat

filename.dir

flag (str) –

'r': Open existing database for reading only.

'w': Open existing database for reading and writing.

'c' (default): Open database for reading and writing, creating it if it doesn’t exist.

'n': Always create a new, empty database, open for reading and writing.

mode (int) – The Unix file access mode of the file (default: octal 0o666), used only when the database has to be created.

경고

파이썬 AST 컴파일러의 스택 깊이 제한으로 인해, 충분히 큰/복잡한 항목이 있는 데이터베이스를 로드할 때 파이썬 인터프리터가 충돌할 수 있습니다.

버전 3.5에서 변경: open() always creates a new database when flag is 'n'.

버전 3.8에서 변경: A database opened read-only if flag is 'r'. A database is not created if it does not exist if flag is 'r' or 'w'.

버전 3.11에서 변경: filename accepts a path-like object.

In addition to the methods provided by the collections.abc.MutableMapping class, the following methods are provided:

dumbdbm.sync()

디스크 상의 디렉터리와 데이터 파일을 동기화합니다. 이 메서드는 Shelve.sync() 메서드에 의해 호출됩니다.

dumbdbm.close()

Close the database.

sqlite3 — DB-API 2.0 interface for SQLite databases

소스 코드: Lib/sqlite3/ [https://github.com/python/cpython/tree/main/Lib/sqlite3/]

SQLite는 별도의 서버 프로세스가 필요 없고 SQL 질의 언어의 비표준 변형을 사용하여 데이터베이스에 액세스할 수 있는 경량 디스크 기반 데이터베이스를 제공하는 C 라이브러리입니다. 일부 응용 프로그램은 내부 데이터 저장을 위해 SQLite를 사용할 수 있습니다. SQLite를 사용하여 응용 프로그램을 프로토타입 한 다음 PostgreSQL 이나 Oracle과 같은 더 큰 데이터베이스로 코드를 이식할 수도 있습니다.

The sqlite3 module was written by Gerhard Häring. It provides an SQL interface compliant with the DB-API 2.0 specification described by PEP 249 [https://peps.python.org/pep-0249/], and requires SQLite 3.15.2 or newer.

This document includes four main sections:

Tutorial teaches how to use the sqlite3 module.

Reference describes the classes and functions this module defines.

How-to guides details how to handle specific tasks.

Explanation provides in-depth background on transaction control.

더 보기

https://www.sqlite.org

SQLite 웹 페이지; 설명서는 지원되는 SQL 언어에 대한 문법과 사용 가능한 데이터형을 설명합니다.

https://www.w3schools.com/sql/

SQL 문법 학습을 위한 자습서, 레퍼런스 및 예제

PEP 249 [https://peps.python.org/pep-0249/] - 데이터베이스 API 명세 2.0

Marc-André Lemburg가 작성한 PEP.

Tutorial

In this tutorial, you will create a database of Monty Python movies using basic sqlite3 functionality. It assumes a fundamental understanding of database concepts, including cursors [https://en.wikipedia.org/wiki/Cursor_(databases)] and transactions [https://en.wikipedia.org/wiki/Database_transaction].

First, we need to create a new database and open a database connection to allow sqlite3 to work with it. Call sqlite3.connect() to create a connection to the database tutorial.db in the current working directory, implicitly creating it if it does not exist:

import sqlite3
con = sqlite3.connect("tutorial.db")

The returned Connection object con represents the connection to the on-disk database.

In order to execute SQL statements and fetch results from SQL queries, we will need to use a database cursor. Call con.cursor() to create the Cursor:

cur = con.cursor()

Now that we’ve got a database connection and a cursor, we can create a database table movie with columns for title, release year, and review score. For simplicity, we can just use column names in the table declaration – thanks to the flexible typing [https://www.sqlite.org/flextypegood.html] feature of SQLite, specifying the data types is optional. Execute the CREATE TABLE statement by calling cur.execute(...):

cur.execute("CREATE TABLE movie(title, year, score)")

We can verify that the new table has been created by querying the sqlite_master table built-in to SQLite, which should now contain an entry for the movie table definition (see The Schema Table [https://www.sqlite.org/schematab.html] for details). Execute that query by calling cur.execute(...), assign the result to res, and call res.fetchone() to fetch the resulting row:

>>> res = cur.execute("SELECT name FROM sqlite_master")
>>> res.fetchone()
('movie',)

We can see that the table has been created, as the query returns a tuple containing the table’s name. If we query sqlite_master for a non-existent table spam, res.fetchone() will return None:

>>> res = cur.execute("SELECT name FROM sqlite_master WHERE name='spam'")
>>> res.fetchone() is None
True

Now, add two rows of data supplied as SQL literals by executing an INSERT statement, once again by calling cur.execute(...):

cur.execute("""
    INSERT INTO movie VALUES
        ('Monty Python and the Holy Grail', 1975, 8.2),
        ('And Now for Something Completely Different', 1971, 7.5)
""")

The INSERT statement implicitly opens a transaction, which needs to be committed before changes are saved in the database (see Transaction control for details). Call con.commit() on the connection object to commit the transaction:

con.commit()

We can verify that the data was inserted correctly by executing a SELECT query. Use the now-familiar cur.execute(...) to assign the result to res, and call res.fetchall() to return all resulting rows:

>>> res = cur.execute("SELECT score FROM movie")
>>> res.fetchall()
[(8.2,), (7.5,)]

The result is a list of two tuples, one per row, each containing that row’s score value.

Now, insert three more rows by calling cur.executemany(...):

data = [
    ("Monty Python Live at the Hollywood Bowl", 1982, 7.9),
    ("Monty Python's The Meaning of Life", 1983, 7.5),
    ("Monty Python's Life of Brian", 1979, 8.0),
]
cur.executemany("INSERT INTO movie VALUES(?, ?, ?)", data)
con.commit()  # Remember to commit the transaction after executing INSERT.

Notice that ? placeholders are used to bind data to the query. Always use placeholders instead of string formatting to bind Python values to SQL statements, to avoid SQL injection attacks [https://en.wikipedia.org/wiki/SQL_injection] (see How to use placeholders to bind values in SQL queries for more details).

We can verify that the new rows were inserted by executing a SELECT query, this time iterating over the results of the query:

>>> for row in cur.execute("SELECT year, title FROM movie ORDER BY year"):
...     print(row)
(1971, 'And Now for Something Completely Different')
(1975, 'Monty Python and the Holy Grail')
(1979, "Monty Python's Life of Brian")
(1982, 'Monty Python Live at the Hollywood Bowl')
(1983, "Monty Python's The Meaning of Life")

Each row is a two-item tuple of (year, title), matching the columns selected in the query.

Finally, verify that the database has been written to disk by calling con.close() to close the existing connection, opening a new one, creating a new cursor, then querying the database:

>>> con.close()
>>> new_con = sqlite3.connect("tutorial.db")
>>> new_cur = new_con.cursor()
>>> res = new_cur.execute("SELECT title, year FROM movie ORDER BY score DESC")
>>> title, year = res.fetchone()
>>> print(f'The highest scoring Monty Python movie is {title!r}, released in {year}')
The highest scoring Monty Python movie is 'Monty Python and the Holy Grail', released in 1975
>>> new_con.close()

You’ve now created an SQLite database using the sqlite3 module, inserted data and retrieved values from it in multiple ways.

더 보기

How-to guides for further reading:

How to use placeholders to bind values in SQL queries

How to adapt custom Python types to SQLite values

How to convert SQLite values to custom Python types

How to use the connection context manager

How to create and use row factories

Explanation for in-depth background on transaction control.

Reference

Module functions

sqlite3.connect(database, timeout=5.0, detect_types=0, isolation_level='DEFERRED', check_same_thread=True, factory=sqlite3.Connection, cached_statements=128, uri=False, *, autocommit=sqlite3.LEGACY_TRANSACTION_CONTROL)

Open a connection to an SQLite database.

매개변수:

database (path-like object) – The path to the database file to be opened. You can pass ":memory:" to create an SQLite database existing only in memory [https://sqlite.org/inmemorydb.html], and open a connection to it.

timeout (float) – How many seconds the connection should wait before raising an OperationalError when a table is locked. If another connection opens a transaction to modify a table, that table will be locked until the transaction is committed. Default five seconds.

detect_types (int) – Control whether and how data types not natively supported by SQLite are looked up to be converted to Python types, using the converters registered with register_converter(). Set it to any combination (using |, bitwise or) of PARSE_DECLTYPES and PARSE_COLNAMES to enable this. Column names takes precedence over declared types if both flags are set. Types cannot be detected for generated fields (for example max(data)), even when the detect_types parameter is set; str will be returned instead. By default (0), type detection is disabled.

isolation_level (str | None) – Control legacy transaction handling behaviour. See Connection.isolation_level and Transaction control via the isolation_level attribute for more information. Can be "DEFERRED" (default), "EXCLUSIVE" or "IMMEDIATE"; or None to disable opening transactions implicitly. Has no effect unless Connection.autocommit is set to LEGACY_TRANSACTION_CONTROL (the default).

check_same_thread (bool) – If True (default), ProgrammingError will be raised if the database connection is used by a thread other than the one that created it. If False, the connection may be accessed in multiple threads; write operations may need to be serialized by the user to avoid data corruption. See threadsafety for more information.

factory (Connection) – A custom subclass of Connection to create the connection with, if not the default Connection class.

cached_statements (int) – The number of statements that sqlite3 should internally cache for this connection, to avoid parsing overhead. By default, 128 statements.

uri (bool) – If set to True, database is interpreted as a URI with a file path and an optional query string. The scheme part must be "file:", and the path can be relative or absolute. The query string allows passing parameters to SQLite, enabling various How to work with SQLite URIs.

autocommit (bool) – Control PEP 249 [https://peps.python.org/pep-0249/] transaction handling behaviour. See Connection.autocommit and Transaction control via the autocommit attribute for more information. autocommit currently defaults to LEGACY_TRANSACTION_CONTROL. The default will change to False in a future Python release.

반환 형식:

Connection

인자 database로 감사 이벤트(auditing event) sqlite3.connect를 발생시킵니다.

Raises an auditing event sqlite3.connect/handle with argument connection_handle.

버전 3.4에서 변경: uri 매개 변수가 추가되었습니다.

버전 3.7에서 변경: database는 이제 문자열뿐만 아니라 경로류 객체 일 수도 있습니다.

버전 3.10에서 변경: Added the sqlite3.connect/handle auditing event.

버전 3.12에서 변경: Added the autocommit parameter.

버전 3.13에서 변경: Positional use of the parameters timeout, detect_types, isolation_level, check_same_thread, factory, cached_statements, and uri is deprecated. They will become keyword-only parameters in Python 3.15.

sqlite3.complete_statement(statement)

Return True if the string statement appears to contain one or more complete SQL statements. No syntactic verification or parsing of any kind is performed, other than checking that there are no unclosed string literals and the statement is terminated by a semicolon.

For example:

>>> sqlite3.complete_statement("SELECT foo FROM bar;")
True
>>> sqlite3.complete_statement("SELECT foo")
False

This function may be useful during command-line input to determine if the entered text seems to form a complete SQL statement, or if additional input is needed before calling execute().

See runsource() in Lib/sqlite3/__main__.py [https://github.com/python/cpython/tree/main/Lib/sqlite3/__main__.py] for real-world use.

sqlite3.enable_callback_tracebacks(flag, /)

Enable or disable callback tracebacks. By default you will not get any tracebacks in user-defined functions, aggregates, converters, authorizer callbacks etc. If you want to debug them, you can call this function with flag set to True. Afterwards, you will get tracebacks from callbacks on sys.stderr. Use False to disable the feature again.

참고

Errors in user-defined function callbacks are logged as unraisable exceptions. Use an unraisable hook handler for introspection of the failed callback.

sqlite3.register_adapter(type, adapter, /)

Register an adapter callable to adapt the Python type type into an SQLite type. The adapter is called with a Python object of type type as its sole argument, and must return a value of a type that SQLite natively understands.

sqlite3.register_converter(typename, converter, /)

Register the converter callable to convert SQLite objects of type typename into a Python object of a specific type. The converter is invoked for all SQLite values of type typename; it is passed a bytes object and should return an object of the desired Python type. Consult the parameter detect_types of connect() for information regarding how type detection works.

Note: typename and the name of the type in your query are matched case-insensitively.

Module constants

sqlite3.LEGACY_TRANSACTION_CONTROL

Set autocommit to this constant to select old style (pre-Python 3.12) transaction control behaviour. See Transaction control via the isolation_level attribute for more information.

sqlite3.PARSE_COLNAMES

Pass this flag value to the detect_types parameter of connect() to look up a converter function by using the type name, parsed from the query column name, as the converter dictionary key. The type name must be wrapped in square brackets ([]).

SELECT p as "p [point]" FROM test;  ! will look up converter "point"

This flag may be combined with PARSE_DECLTYPES using the | (bitwise or) operator.

sqlite3.PARSE_DECLTYPES

Pass this flag value to the detect_types parameter of connect() to look up a converter function using the declared types for each column. The types are declared when the database table is created. sqlite3 will look up a converter function using the first word of the declared type as the converter dictionary key. For example:

CREATE TABLE test(
   i integer primary key,  ! will look up a converter named "integer"
   p point,                ! will look up a converter named "point"
   n number(10)            ! will look up a converter named "number"
 )

This flag may be combined with PARSE_COLNAMES using the | (bitwise or) operator.

sqlite3.SQLITE_OK

sqlite3.SQLITE_DENY

sqlite3.SQLITE_IGNORE

Flags that should be returned by the authorizer_callback callable passed to Connection.set_authorizer(), to indicate whether:

Access is allowed (SQLITE_OK),

The SQL statement should be aborted with an error (SQLITE_DENY)

The column should be treated as a NULL value (SQLITE_IGNORE)

sqlite3.apilevel

String constant stating the supported DB-API level. Required by the DB-API. Hard-coded to "2.0".

sqlite3.paramstyle

String constant stating the type of parameter marker formatting expected by the sqlite3 module. Required by the DB-API. Hard-coded to "qmark".

참고

The named DB-API parameter style is also supported.

sqlite3.sqlite_version

Version number of the runtime SQLite library as a string.

sqlite3.sqlite_version_info

Version number of the runtime SQLite library as a tuple of integers.

sqlite3.threadsafety

Integer constant required by the DB-API 2.0, stating the level of thread safety the sqlite3 module supports. This attribute is set based on the default threading mode [https://sqlite.org/threadsafe.html] the underlying SQLite library is compiled with. The SQLite threading modes are:

Single-thread: In this mode, all mutexes are disabled and SQLite is unsafe to use in more than a single thread at once.

Multi-thread: In this mode, SQLite can be safely used by multiple threads provided that no single database connection is used simultaneously in two or more threads.

Serialized: In serialized mode, SQLite can be safely used by multiple threads with no restriction.

The mappings from SQLite threading modes to DB-API 2.0 threadsafety levels are as follows:

SQLite threading mode

threadsafety [https://peps.python.org/pep-0249/#threadsafety]

SQLITE_THREADSAFE [https://sqlite.org/compile.html#threadsafe]

DB-API 2.0 meaning

single-thread

0

0

Threads may not share the module

multi-thread

1

2

Threads may share the module, but not connections

serialized

3

1

Threads may share the module, connections and cursors

버전 3.11에서 변경: Set threadsafety dynamically instead of hard-coding it to 1.

sqlite3.SQLITE_DBCONFIG_DEFENSIVE

sqlite3.SQLITE_DBCONFIG_DQS_DDL

sqlite3.SQLITE_DBCONFIG_DQS_DML

sqlite3.SQLITE_DBCONFIG_ENABLE_FKEY

sqlite3.SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER

sqlite3.SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION

sqlite3.SQLITE_DBCONFIG_ENABLE_QPSG

sqlite3.SQLITE_DBCONFIG_ENABLE_TRIGGER

sqlite3.SQLITE_DBCONFIG_ENABLE_VIEW

sqlite3.SQLITE_DBCONFIG_LEGACY_ALTER_TABLE

sqlite3.SQLITE_DBCONFIG_LEGACY_FILE_FORMAT

sqlite3.SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE

sqlite3.SQLITE_DBCONFIG_RESET_DATABASE

sqlite3.SQLITE_DBCONFIG_TRIGGER_EQP

sqlite3.SQLITE_DBCONFIG_TRUSTED_SCHEMA

sqlite3.SQLITE_DBCONFIG_WRITABLE_SCHEMA

These constants are used for the Connection.setconfig() and getconfig() methods.

The availability of these constants varies depending on the version of SQLite Python was compiled with.

Added in version 3.12.

더 보기

https://www.sqlite.org/c3ref/c_dbconfig_defensive.html

SQLite docs: Database Connection Configuration Options

Deprecated since version 3.12, removed in version 3.14: The version and version_info constants.

Connection objects

class sqlite3.Connection

Each open SQLite database is represented by a Connection object, which is created using sqlite3.connect(). Their main purpose is creating Cursor objects, and Transaction control.

더 보기

How to use connection shortcut methods

How to use the connection context manager

버전 3.13에서 변경: A ResourceWarning is emitted if close() is not called before a Connection object is deleted.

An SQLite database connection has the following attributes and methods:

cursor(factory=Cursor)

Create and return a Cursor object. The cursor method accepts a single optional parameter factory. If supplied, this must be a callable returning an instance of Cursor or its subclasses.

blobopen(table, column, row, /, *, readonly=False, name='main')

Open a Blob handle to an existing BLOB.

매개변수:

table (str) – The name of the table where the blob is located.

column (str) – The name of the column where the blob is located.

row (str) – The name of the row where the blob is located.

readonly (bool) – Set to True if the blob should be opened without write permissions. Defaults to False.

name (str) – The name of the database where the blob is located. Defaults to "main".

예외 발생:

OperationalError – When trying to open a blob in a WITHOUT ROWID table.

반환 형식:

Blob

참고

The blob size cannot be changed using the Blob class. Use the SQL function zeroblob to create a blob with a fixed size.

Added in version 3.11.

commit()

Commit any pending transaction to the database. If autocommit is True, or there is no open transaction, this method does nothing. If autocommit is False, a new transaction is implicitly opened if a pending transaction was committed by this method.

rollback()

Roll back to the start of any pending transaction. If autocommit is True, or there is no open transaction, this method does nothing. If autocommit is False, a new transaction is implicitly opened if a pending transaction was rolled back by this method.

close()

Close the database connection. If autocommit is False, any pending transaction is implicitly rolled back. If autocommit is True or LEGACY_TRANSACTION_CONTROL, no implicit transaction control is executed. Make sure to commit() before closing to avoid losing pending changes.

execute(sql, parameters=(), /)

Create a new Cursor object and call execute() on it with the given sql and parameters. Return the new cursor object.

executemany(sql, parameters, /)

Create a new Cursor object and call executemany() on it with the given sql and parameters. Return the new cursor object.

executescript(sql_script, /)

Create a new Cursor object and call executescript() on it with the given sql_script. Return the new cursor object.

create_function(name, narg, func, *, deterministic=False)

Create or remove a user-defined SQL function.

매개변수:

name (str) – The name of the SQL function.

narg (int) – The number of arguments the SQL function can accept. If -1, it may take any number of arguments.

func (callback | None) – A callable that is called when the SQL function is invoked. The callable must return a type natively supported by SQLite. Set to None to remove an existing SQL function.

deterministic (bool) – If True, the created SQL function is marked as deterministic [https://sqlite.org/deterministic.html], which allows SQLite to perform additional optimizations.

버전 3.8에서 변경: Added the deterministic parameter.

예:

>>> import hashlib
>>> def md5sum(t):
...     return hashlib.md5(t).hexdigest()
>>> con = sqlite3.connect(":memory:")
>>> con.create_function("md5", 1, md5sum)
>>> for row in con.execute("SELECT md5(?)", (b"foo",)):
...     print(row)
('acbd18db4cc2f85cedef654fccc4a4d8',)
>>> con.close()

버전 3.13에서 변경: Passing name, narg, and func as keyword arguments is deprecated. These parameters will become positional-only in Python 3.15.

create_aggregate(name, n_arg, aggregate_class)

Create or remove a user-defined SQL aggregate function.

매개변수:

name (str) – The name of the SQL aggregate function.

n_arg (int) – The number of arguments the SQL aggregate function can accept. If -1, it may take any number of arguments.

aggregate_class (class | None) –

A class must implement the following methods:

step(): Add a row to the aggregate.

finalize(): Return the final result of the aggregate as a type natively supported by SQLite.

The number of arguments that the step() method must accept is controlled by n_arg.

Set to None to remove an existing SQL aggregate function.

예:

class MySum:
    def __init__(self):
        self.count = 0

    def step(self, value):
        self.count += value

    def finalize(self):
        return self.count

con = sqlite3.connect(":memory:")
con.create_aggregate("mysum", 1, MySum)
cur = con.execute("CREATE TABLE test(i)")
cur.execute("INSERT INTO test(i) VALUES(1)")
cur.execute("INSERT INTO test(i) VALUES(2)")
cur.execute("SELECT mysum(i) FROM test")
print(cur.fetchone()[0])

con.close()

버전 3.13에서 변경: Passing name, n_arg, and aggregate_class as keyword arguments is deprecated. These parameters will become positional-only in Python 3.15.

create_window_function(name, num_params, aggregate_class, /)

Create or remove a user-defined aggregate window function.

매개변수:

name (str) – The name of the SQL aggregate window function to create or remove.

num_params (int) – The number of arguments the SQL aggregate window function can accept. If -1, it may take any number of arguments.

aggregate_class (class | None) –

A class that must implement the following methods:

step(): Add a row to the current window.

value(): Return the current value of the aggregate.

inverse(): Remove a row from the current window.

finalize(): Return the final result of the aggregate as a type natively supported by SQLite.

The number of arguments that the step() and value() methods must accept is controlled by num_params.

Set to None to remove an existing SQL aggregate window function.

예외 발생:

NotSupportedError – If used with a version of SQLite older than 3.25.0, which does not support aggregate window functions.

Added in version 3.11.

예:

# Example taken from https://www.sqlite.org/windowfunctions.html#udfwinfunc
class WindowSumInt:
    def __init__(self):
        self.count = 0

    def step(self, value):
        """Add a row to the current window."""
        self.count += value

    def value(self):
        """Return the current value of the aggregate."""
        return self.count

    def inverse(self, value):
        """Remove a row from the current window."""
        self.count -= value

    def finalize(self):
        """Return the final value of the aggregate.

        Any clean-up actions should be placed here.
        """
        return self.count

con = sqlite3.connect(":memory:")
cur = con.execute("CREATE TABLE test(x, y)")
values = [
    ("a", 4),
    ("b", 5),
    ("c", 3),
    ("d", 8),
    ("e", 1),
]
cur.executemany("INSERT INTO test VALUES(?, ?)", values)
con.create_window_function("sumint", 1, WindowSumInt)
cur.execute("""
    SELECT x, sumint(y) OVER (
        ORDER BY x ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING
    ) AS sum_y
    FROM test ORDER BY x
""")
print(cur.fetchall())
con.close()

create_collation(name, callable, /)

Create a collation named name using the collating function callable. callable is passed two string arguments, and it should return an integer:

1 if the first is ordered higher than the second

-1 if the first is ordered lower than the second

0 if they are ordered equal

The following example shows a reverse sorting collation:

def collate_reverse(string1, string2):
    if string1 == string2:
        return 0
    elif string1 < string2:
        return 1
    else:
        return -1

con = sqlite3.connect(":memory:")
con.create_collation("reverse", collate_reverse)

cur = con.execute("CREATE TABLE test(x)")
cur.executemany("INSERT INTO test(x) VALUES(?)", [("a",), ("b",)])
cur.execute("SELECT x FROM test ORDER BY x COLLATE reverse")
for row in cur:
    print(row)
con.close()

Remove a collation function by setting callable to None.

버전 3.11에서 변경: The collation name can contain any Unicode character. Earlier, only ASCII characters were allowed.

interrupt()

Call this method from a different thread to abort any queries that might be executing on the connection. Aborted queries will raise an OperationalError.

set_authorizer(authorizer_callback)

Register callable authorizer_callback to be invoked for each attempt to access a column of a table in the database. The callback should return one of SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE to signal how access to the column should be handled by the underlying SQLite library.

The first argument to the callback signifies what kind of operation is to be authorized. The second and third argument will be arguments or None depending on the first argument. The 4th argument is the name of the database (“main”, “temp”, etc.) if applicable. The 5th argument is the name of the inner-most trigger or view that is responsible for the access attempt or None if this access attempt is directly from input SQL code.

Please consult the SQLite documentation about the possible values for the first argument and the meaning of the second and third argument depending on the first one. All necessary constants are available in the sqlite3 module.

Passing None as authorizer_callback will disable the authorizer.

버전 3.11에서 변경: Added support for disabling the authorizer using None.

버전 3.13에서 변경: Passing authorizer_callback as a keyword argument is deprecated. The parameter will become positional-only in Python 3.15.

set_progress_handler(progress_handler, n)

Register callable progress_handler to be invoked for every n instructions of the SQLite virtual machine. This is useful if you want to get called from SQLite during long-running operations, for example to update a GUI.

If you want to clear any previously installed progress handler, call the method with None for progress_handler.

Returning a non-zero value from the handler function will terminate the currently executing query and cause it to raise a DatabaseError exception.

버전 3.13에서 변경: Passing progress_handler as a keyword argument is deprecated. The parameter will become positional-only in Python 3.15.

set_trace_callback(trace_callback)

Register callable trace_callback to be invoked for each SQL statement that is actually executed by the SQLite backend.

The only argument passed to the callback is the statement (as str) that is being executed. The return value of the callback is ignored. Note that the backend does not only run statements passed to the Cursor.execute() methods. Other sources include the transaction management of the sqlite3 module and the execution of triggers defined in the current database.

Passing None as trace_callback will disable the trace callback.

참고

Exceptions raised in the trace callback are not propagated. As a development and debugging aid, use enable_callback_tracebacks() to enable printing tracebacks from exceptions raised in the trace callback.

Added in version 3.3.

버전 3.13에서 변경: Passing trace_callback as a keyword argument is deprecated. The parameter will become positional-only in Python 3.15.

enable_load_extension(enabled, /)

Enable the SQLite engine to load SQLite extensions from shared libraries if enabled is True; else, disallow loading SQLite extensions. SQLite extensions can define new functions, aggregates or whole new virtual table implementations. One well-known extension is the fulltext-search extension distributed with SQLite.

참고

The sqlite3 module is not built with loadable extension support by default, because some platforms (notably macOS) have SQLite libraries which are compiled without this feature. To get loadable extension support, you must pass the --enable-loadable-sqlite-extensions option to configure.

Raises an auditing event sqlite3.enable_load_extension with arguments connection, enabled.

Added in version 3.2.

버전 3.10에서 변경: Added the sqlite3.enable_load_extension auditing event.

con.enable_load_extension(True)

# Load the fulltext search extension
con.execute("select load_extension('./fts3.so')")

# alternatively you can load the extension using an API call:
# con.load_extension("./fts3.so")

# disable extension loading again
con.enable_load_extension(False)

# example from SQLite wiki
con.execute("CREATE VIRTUAL TABLE recipe USING fts3(name, ingredients)")
con.executescript("""
    INSERT INTO recipe (name, ingredients) VALUES('broccoli stew', 'broccoli peppers cheese tomatoes');
    INSERT INTO recipe (name, ingredients) VALUES('pumpkin stew', 'pumpkin onions garlic celery');
    INSERT INTO recipe (name, ingredients) VALUES('broccoli pie', 'broccoli cheese onions flour');
    INSERT INTO recipe (name, ingredients) VALUES('pumpkin pie', 'pumpkin sugar flour butter');
    """)
for row in con.execute("SELECT rowid, name, ingredients FROM recipe WHERE name MATCH 'pie'"):
    print(row)

load_extension(path, /, *, entrypoint=None)

Load an SQLite extension from a shared library. Enable extension loading with enable_load_extension() before calling this method.

매개변수:

path (str) – The path to the SQLite extension.

entrypoint (str | None) – Entry point name. If None (the default), SQLite will come up with an entry point name of its own; see the SQLite docs Loading an Extension [https://www.sqlite.org/loadext.html#loading_an_extension] for details.

Raises an auditing event sqlite3.load_extension with arguments connection, path.

Added in version 3.2.

버전 3.10에서 변경: Added the sqlite3.load_extension auditing event.

버전 3.12에서 변경: Added the entrypoint parameter.

iterdump(*, filter=None)

Return an iterator to dump the database as SQL source code. Useful when saving an in-memory database for later restoration. Similar to the .dump command in the sqlite3 shell.

매개변수:

filter (str | None) – An optional LIKE pattern for database objects to dump, e.g. prefix_%. If None (the default), all database objects will be included.

예:

# Convert file example.db to SQL dump file dump.sql
con = sqlite3.connect('example.db')
with open('dump.sql', 'w') as f:
    for line in con.iterdump():
        f.write('%s\n' % line)
con.close()

더 보기

How to handle non-UTF-8 text encodings

버전 3.13에서 변경: Added the filter parameter.

backup(target, *, pages=-1, progress=None, name='main', sleep=0.250)

Create a backup of an SQLite database.

Works even if the database is being accessed by other clients or concurrently by the same connection.

매개변수:

target (Connection) – The database connection to save the backup to.

pages (int) – The number of pages to copy at a time. If equal to or less than 0, the entire database is copied in a single step. Defaults to -1.

progress (callback | None) – If set to a callable, it is invoked with three integer arguments for every backup iteration: the status of the last iteration, the remaining number of pages still to be copied, and the total number of pages. Defaults to None.

name (str) – The name of the database to back up. Either "main" (the default) for the main database, "temp" for the temporary database, or the name of a custom database as attached using the ATTACH DATABASE SQL statement.

sleep (float) – The number of seconds to sleep between successive attempts to back up remaining pages.

Example 1, copy an existing database into another:

def progress(status, remaining, total):
    print(f'Copied {total-remaining} of {total} pages...')

src = sqlite3.connect('example.db')
dst = sqlite3.connect('backup.db')
with dst:
    src.backup(dst, pages=1, progress=progress)
dst.close()
src.close()

Example 2, copy an existing database into a transient copy:

src = sqlite3.connect('example.db')
dst = sqlite3.connect(':memory:')
src.backup(dst)
dst.close()
src.close()

Added in version 3.7.

더 보기

How to handle non-UTF-8 text encodings

getlimit(category, /)

Get a connection runtime limit.

매개변수:

category (int) – The SQLite limit category [https://www.sqlite.org/c3ref/c_limit_attached.html] to be queried.

반환 형식:

int

예외 발생:

ProgrammingError – If category is not recognised by the underlying SQLite library.

Example, query the maximum length of an SQL statement for Connection con (the default is 1000000000):

>>> con.getlimit(sqlite3.SQLITE_LIMIT_SQL_LENGTH)
1000000000

Added in version 3.11.

setlimit(category, limit, /)

Set a connection runtime limit. Attempts to increase a limit above its hard upper bound are silently truncated to the hard upper bound. Regardless of whether or not the limit was changed, the prior value of the limit is returned.

매개변수:

category (int) – The SQLite limit category [https://www.sqlite.org/c3ref/c_limit_attached.html] to be set.

limit (int) – The value of the new limit. If negative, the current limit is unchanged.

반환 형식:

int

예외 발생:

ProgrammingError – If category is not recognised by the underlying SQLite library.

Example, limit the number of attached databases to 1 for Connection con (the default limit is 10):

>>> con.setlimit(sqlite3.SQLITE_LIMIT_ATTACHED, 1)
10
>>> con.getlimit(sqlite3.SQLITE_LIMIT_ATTACHED)
1

Added in version 3.11.

getconfig(op, /)

Query a boolean connection configuration option.

매개변수:

op (int) – A SQLITE_DBCONFIG code.

반환 형식:

bool

Added in version 3.12.

setconfig(op, enable=True, /)

Set a boolean connection configuration option.

매개변수:

op (int) – A SQLITE_DBCONFIG code.

enable (bool) – True if the configuration option should be enabled (default); False if it should be disabled.

Added in version 3.12.

serialize(*, name='main')

Serialize a database into a bytes object. For an ordinary on-disk database file, the serialization is just a copy of the disk file. For an in-memory database or a “temp” database, the serialization is the same sequence of bytes which would be written to disk if that database were backed up to disk.

매개변수:

name (str) – The database name to be serialized. Defaults to "main".

반환 형식:

bytes

참고

This method is only available if the underlying SQLite library has the serialize API.

Added in version 3.11.

deserialize(data, /, *, name='main')

Deserialize a serialized database into a Connection. This method causes the database connection to disconnect from database name, and reopen name as an in-memory database based on the serialization contained in data.

매개변수:

data (bytes) – A serialized database.

name (str) – The database name to deserialize into. Defaults to "main".

예외 발생:

OperationalError – If the database connection is currently involved in a read transaction or a backup operation.

DatabaseError – If data does not contain a valid SQLite database.

OverflowError – If len(data) is larger than 2**63 - 1.

참고

This method is only available if the underlying SQLite library has the deserialize API.

Added in version 3.11.

autocommit

This attribute controls PEP 249 [https://peps.python.org/pep-0249/]-compliant transaction behaviour. autocommit has three allowed values:

False: Select PEP 249 [https://peps.python.org/pep-0249/]-compliant transaction behaviour, implying that sqlite3 ensures a transaction is always open. Use commit() and rollback() to close transactions.

This is the recommended value of autocommit.

True: Use SQLite’s autocommit mode [https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions]. commit() and rollback() have no effect in this mode.

LEGACY_TRANSACTION_CONTROL: Pre-Python 3.12 (non-PEP 249 [https://peps.python.org/pep-0249/]-compliant) transaction control. See isolation_level for more details.

This is currently the default value of autocommit.

Changing autocommit to False will open a new transaction, and changing it to True will commit any pending transaction.

See Transaction control via the autocommit attribute for more details.

참고

The isolation_level attribute has no effect unless autocommit is LEGACY_TRANSACTION_CONTROL.

Added in version 3.12.

in_transaction

This read-only attribute corresponds to the low-level SQLite autocommit mode [https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions].

True if a transaction is active (there are uncommitted changes), False otherwise.

Added in version 3.2.

isolation_level

Controls the legacy transaction handling mode of sqlite3. If set to None, transactions are never implicitly opened. If set to one of "DEFERRED", "IMMEDIATE", or "EXCLUSIVE", corresponding to the underlying SQLite transaction behaviour [https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions], implicit transaction management is performed.

If not overridden by the isolation_level parameter of connect(), the default is "", which is an alias for "DEFERRED".

참고

Using autocommit to control transaction handling is recommended over using isolation_level. isolation_level has no effect unless autocommit is set to LEGACY_TRANSACTION_CONTROL (the default).

row_factory

The initial row_factory for Cursor objects created from this connection. Assigning to this attribute does not affect the row_factory of existing cursors belonging to this connection, only new ones. Is None by default, meaning each row is returned as a tuple.

See How to create and use row factories for more details.

text_factory

A callable that accepts a bytes parameter and returns a text representation of it. The callable is invoked for SQLite values with the TEXT data type. By default, this attribute is set to str.

See How to handle non-UTF-8 text encodings for more details.

total_changes

Return the total number of database rows that have been modified, inserted, or deleted since the database connection was opened.

Cursor objects

A Cursor object represents a database cursor [https://en.wikipedia.org/wiki/Cursor_(databases)] which is used to execute SQL statements, and manage the context of a fetch operation. Cursors are created using Connection.cursor(), or by using any of the connection shortcut methods.

Cursor objects are iterators, meaning that if you execute() a SELECT query, you can simply iterate over the cursor to fetch the resulting rows:

for row in cur.execute("SELECT t FROM data"):
    print(row)

class sqlite3.Cursor

Cursor 인스턴스에는 다음과 같은 어트리뷰트와 메서드가 있습니다.

execute(sql, parameters=(), /)

Execute a single SQL statement, optionally binding Python values using placeholders.

매개변수:

sql (str) – A single SQL statement.

parameters (dict | sequence) – Python values to bind to placeholders in sql. A dict if named placeholders are used. A sequence if unnamed placeholders are used. See How to use placeholders to bind values in SQL queries.

예외 발생:

ProgrammingError – If sql contains more than one SQL statement.

If autocommit is LEGACY_TRANSACTION_CONTROL, isolation_level is not None, sql is an INSERT, UPDATE, DELETE, or REPLACE statement, and there is no open transaction, a transaction is implicitly opened before executing sql.

Deprecated since version 3.12, removed in version 3.14: DeprecationWarning is emitted if named placeholders are used and parameters is a sequence instead of a dict. Starting with Python 3.14, ProgrammingError will be raised instead.

Use executescript() to execute multiple SQL statements.

executemany(sql, parameters, /)

For every item in parameters, repeatedly execute the parameterized DML SQL statement sql.

Uses the same implicit transaction handling as execute().

매개변수:

sql (str) – A single SQL DML statement.

parameters (iterable) – An iterable of parameters to bind with the placeholders in sql. See How to use placeholders to bind values in SQL queries.

예외 발생:

ProgrammingError – If sql contains more than one SQL statement, or is not a DML statement.

예:

rows = [
    ("row1",),
    ("row2",),
]
# cur is an sqlite3.Cursor object
cur.executemany("INSERT INTO data VALUES(?)", rows)

참고

Any resulting rows are discarded, including DML statements with RETURNING clauses [https://www.sqlite.org/lang_returning.html].

Deprecated since version 3.12, removed in version 3.14: DeprecationWarning is emitted if named placeholders are used and the items in parameters are sequences instead of dicts. Starting with Python 3.14, ProgrammingError will be raised instead.

executescript(sql_script, /)

Execute the SQL statements in sql_script. If the autocommit is LEGACY_TRANSACTION_CONTROL and there is a pending transaction, an implicit COMMIT statement is executed first. No other implicit transaction control is performed; any transaction control must be added to sql_script.

sql_script must be a string.

예:

# cur is an sqlite3.Cursor object
cur.executescript("""
    BEGIN;
    CREATE TABLE person(firstname, lastname, age);
    CREATE TABLE book(title, author, published);
    CREATE TABLE publisher(name, address);
    COMMIT;
""")

fetchone()

If row_factory is None, return the next row query result set as a tuple. Else, pass it to the row factory and return its result. Return None if no more data is available.

fetchmany(size=cursor.arraysize)

Return the next set of rows of a query result as a list. Return an empty list if no more rows are available.

The number of rows to fetch per call is specified by the size parameter. If size is not given, arraysize determines the number of rows to be fetched. If fewer than size rows are available, as many rows as are available are returned.

size 매개 변수와 관련된 성능 고려 사항이 있습니다. 최적의 성능을 위해서, 일반적으로 arraysize 어트리뷰트를 사용하는 것이 가장 좋습니다. size 매개 변수가 사용되면, fetchmany() 호출마다 같은 값을 유지하는 것이 가장 좋습니다.

fetchall()

Return all (remaining) rows of a query result as a list. Return an empty list if no rows are available. Note that the arraysize attribute can affect the performance of this operation.

close()

(__del__이 호출 될 때가 아니라) 지금 커서를 닫습니다.

이 시점부터는 커서를 사용할 수 없습니다; 커서로 어떤 연산이건 시도하면 ProgrammingError 예외가 발생합니다.

setinputsizes(sizes, /)

Required by the DB-API. Does nothing in sqlite3.

setoutputsize(size, column=None, /)

Required by the DB-API. Does nothing in sqlite3.

arraysize

fetchmany()에 의해 반환되는 행의 수를 제어하는 읽기/쓰기 어트리뷰트. 기본값은 1입니다. 이는 호출 당 하나의 행을 가져오는 것을 뜻합니다.

connection

Read-only attribute that provides the SQLite database Connection belonging to the cursor. A Cursor object created by calling con.cursor() will have a connection attribute that refers to con:

>>> con = sqlite3.connect(":memory:")
>>> cur = con.cursor()
>>> cur.connection == con
True
>>> con.close()

description

Read-only attribute that provides the column names of the last query. To remain compatible with the Python DB API, it returns a 7-tuple for each column where the last six items of each tuple are None.

일치하는 행이 없는 SELECT 문에도 설정됩니다.

lastrowid

Read-only attribute that provides the row id of the last inserted row. It is only updated after successful INSERT or REPLACE statements using the execute() method. For other statements, after executemany() or executescript(), or if the insertion failed, the value of lastrowid is left unchanged. The initial value of lastrowid is None.

참고

Inserts into WITHOUT ROWID tables are not recorded.

버전 3.6에서 변경: REPLACE 문에 대한 지원이 추가되었습니다.

rowcount

Read-only attribute that provides the number of modified rows for INSERT, UPDATE, DELETE, and REPLACE statements; is -1 for other statements, including CTE queries. It is only updated by the execute() and executemany() methods, after the statement has run to completion. This means that any resulting rows must be fetched in order for rowcount to be updated.

row_factory

Control how a row fetched from this Cursor is represented. If None, a row is represented as a tuple. Can be set to the included sqlite3.Row; or a callable that accepts two arguments, a Cursor object and the tuple of row values, and returns a custom object representing an SQLite row.

Defaults to what Connection.row_factory was set to when the Cursor was created. Assigning to this attribute does not affect Connection.row_factory of the parent connection.

See How to create and use row factories for more details.

Row objects

class sqlite3.Row

A Row instance serves as a highly optimized row_factory for Connection objects. It supports iteration, equality testing, len(), and mapping access by column name and index.

Two Row objects compare equal if they have identical column names and values.

See How to create and use row factories for more details.

keys()

Return a list of column names as strings. Immediately after a query, it is the first member of each tuple in Cursor.description.

버전 3.5에서 변경: 슬라이싱 지원이 추가되었습니다.

Blob objects

class sqlite3.Blob

Added in version 3.11.

A Blob instance is a file-like object that can read and write data in an SQLite BLOB. Call len(blob) to get the size (number of bytes) of the blob. Use indices and slices for direct access to the blob data.

Use the Blob as a context manager to ensure that the blob handle is closed after use.

con = sqlite3.connect(":memory:")
con.execute("CREATE TABLE test(blob_col blob)")
con.execute("INSERT INTO test(blob_col) VALUES(zeroblob(13))")

# Write to our blob, using two write operations:
with con.blobopen("test", "blob_col", 1) as blob:
    blob.write(b"hello, ")
    blob.write(b"world.")
    # Modify the first and last bytes of our blob
    blob[0] = ord("H")
    blob[-1] = ord("!")

# Read the contents of our blob
with con.blobopen("test", "blob_col", 1) as blob:
    greeting = blob.read()

print(greeting)  # outputs "b'Hello, world!'"
con.close()

close()

Close the blob.

The blob will be unusable from this point onward. An Error (or subclass) exception will be raised if any further operation is attempted with the blob.

read(length=-1, /)

Read length bytes of data from the blob at the current offset position. If the end of the blob is reached, the data up to EOF will be returned. When length is not specified, or is negative, read() will read until the end of the blob.

write(data, /)

Write data to the blob at the current offset. This function cannot change the blob length. Writing beyond the end of the blob will raise ValueError.

tell()

Return the current access position of the blob.

seek(offset, origin=os.SEEK_SET, /)

Set the current access position of the blob to offset. The origin argument defaults to os.SEEK_SET (absolute blob positioning). Other values for origin are os.SEEK_CUR (seek relative to the current position) and os.SEEK_END (seek relative to the blob’s end).

PrepareProtocol objects

class sqlite3.PrepareProtocol

The PrepareProtocol type’s single purpose is to act as a PEP 246 [https://peps.python.org/pep-0246/] style adaption protocol for objects that can adapt themselves to native SQLite types.

예외

The exception hierarchy is defined by the DB-API 2.0 (PEP 249 [https://peps.python.org/pep-0249/]).

exception sqlite3.Warning

This exception is not currently raised by the sqlite3 module, but may be raised by applications using sqlite3, for example if a user-defined function truncates data while inserting. Warning is a subclass of Exception.

exception sqlite3.Error

The base class of the other exceptions in this module. Use this to catch all errors with one single except statement. Error is a subclass of Exception.

If the exception originated from within the SQLite library, the following two attributes are added to the exception:

sqlite_errorcode

The numeric error code from the SQLite API [https://sqlite.org/rescode.html]

Added in version 3.11.

sqlite_errorname

The symbolic name of the numeric error code from the SQLite API [https://sqlite.org/rescode.html]

Added in version 3.11.

exception sqlite3.InterfaceError

Exception raised for misuse of the low-level SQLite C API. In other words, if this exception is raised, it probably indicates a bug in the sqlite3 module. InterfaceError is a subclass of Error.

exception sqlite3.DatabaseError

Exception raised for errors that are related to the database. This serves as the base exception for several types of database errors. It is only raised implicitly through the specialised subclasses. DatabaseError is a subclass of Error.

exception sqlite3.DataError

Exception raised for errors caused by problems with the processed data, like numeric values out of range, and strings which are too long. DataError is a subclass of DatabaseError.

exception sqlite3.OperationalError

Exception raised for errors that are related to the database’s operation, and not necessarily under the control of the programmer. For example, the database path is not found, or a transaction could not be processed. OperationalError is a subclass of DatabaseError.

exception sqlite3.IntegrityError

데이터베이스의 관계형 무결성이 영향을 받을 때 발생하는 예외. 예를 들어, 외부 키(foreign key) 검사가 실패할 때. DatabaseError의 서브 클래스입니다.

exception sqlite3.InternalError

Exception raised when SQLite encounters an internal error. If this is raised, it may indicate that there is a problem with the runtime SQLite library. InternalError is a subclass of DatabaseError.

exception sqlite3.ProgrammingError

Exception raised for sqlite3 API programming errors, for example supplying the wrong number of bindings to a query, or trying to operate on a closed Connection. ProgrammingError is a subclass of DatabaseError.

exception sqlite3.NotSupportedError

Exception raised in case a method or database API is not supported by the underlying SQLite library. For example, setting deterministic to True in create_function(), if the underlying SQLite library does not support deterministic functions. NotSupportedError is a subclass of DatabaseError.

SQLite 와 파이썬 형

SQLite는 기본적으로 다음 형을 지원합니다: NULL, INTEGER, REAL, TEXT, BLOB.

따라서 다음과 같은 파이썬 형을 아무 문제 없이 SQLite로 보낼 수 있습니다:

파이썬 형

SQLite 형

None

NULL

int

INTEGER

float

REAL

str

TEXT

bytes

BLOB

이것은 SQLite 형이 기본적으로 파이썬 형으로 변환되는 방법입니다:

SQLite 형

파이썬 형

NULL

None

INTEGER

int

REAL

float

TEXT

text_factory에 따라 다릅니다, 기본적으로 str.

BLOB

bytes

The type system of the sqlite3 module is extensible in two ways: you can store additional Python types in an SQLite database via object adapters, and you can let the sqlite3 module convert SQLite types to Python types via converters.

Default adapters and converters (deprecated)

참고

The default adapters and converters are deprecated as of Python 3.12. Instead, use the Adapter and converter recipes and tailor them to your needs.

The deprecated default adapters and converters consist of:

An adapter for datetime.date objects to strings in ISO 8601 [https://en.wikipedia.org/wiki/ISO_8601] format.

An adapter for datetime.datetime objects to strings in ISO 8601 format.

A converter for declared “date” types to datetime.date objects.

A converter for declared “timestamp” types to datetime.datetime objects. Fractional parts will be truncated to 6 digits (microsecond precision).

참고

The default “timestamp” converter ignores UTC offsets in the database and always returns a naive datetime.datetime object. To preserve UTC offsets in timestamps, either leave converters disabled, or register an offset-aware converter with register_converter().

버전 3.12부터 폐지됨.

Command-line interface

The sqlite3 module can be invoked as a script, using the interpreter’s -m switch, in order to provide a simple SQLite shell. The argument signature is as follows:

python -m sqlite3 [-h] [-v] [filename] [sql]

Type .quit or CTRL-D to exit the shell.

-h, --help

Print CLI help.

-v, --version

Print underlying SQLite library version.

Added in version 3.12.

How-to guides

How to use placeholders to bind values in SQL queries

SQL operations usually need to use values from Python variables. However, beware of using Python’s string operations to assemble queries, as they are vulnerable to SQL injection attacks [https://en.wikipedia.org/wiki/SQL_injection]. For example, an attacker can simply close the single quote and inject OR TRUE to select all rows:

>>> # Never do this -- insecure!
>>> symbol = input()
' OR TRUE; --
>>> sql = "SELECT * FROM stocks WHERE symbol = '%s'" % symbol
>>> print(sql)
SELECT * FROM stocks WHERE symbol = '' OR TRUE; --'
>>> cur.execute(sql)

Instead, use the DB-API’s parameter substitution. To insert a variable into a query string, use a placeholder in the string, and substitute the actual values into the query by providing them as a tuple of values to the second argument of the cursor’s execute() method.

An SQL statement may use one of two kinds of placeholders: question marks (qmark style) or named placeholders (named style). For the qmark style, parameters must be a sequence whose length must match the number of placeholders, or a ProgrammingError is raised. For the named style, parameters must be an instance of a dict (or a subclass), which must contain keys for all named parameters; any extra items are ignored. Here’s an example of both styles:

con = sqlite3.connect(":memory:")
cur = con.execute("CREATE TABLE lang(name, first_appeared)")

# This is the named style used with executemany():
data = (
    {"name": "C", "year": 1972},
    {"name": "Fortran", "year": 1957},
    {"name": "Python", "year": 1991},
    {"name": "Go", "year": 2009},
)
cur.executemany("INSERT INTO lang VALUES(:name, :year)", data)

# This is the qmark style used in a SELECT query:
params = (1972,)
cur.execute("SELECT * FROM lang WHERE first_appeared = ?", params)
print(cur.fetchall())
con.close()

참고

PEP 249 [https://peps.python.org/pep-0249/] numeric placeholders are not supported. If used, they will be interpreted as named placeholders.

How to adapt custom Python types to SQLite values

SQLite supports only a limited set of data types natively. To store custom Python types in SQLite databases, adapt them to one of the Python types SQLite natively understands.

There are two ways to adapt Python objects to SQLite types: letting your object adapt itself, or using an adapter callable. The latter will take precedence above the former. For a library that exports a custom type, it may make sense to enable that type to adapt itself. As an application developer, it may make more sense to take direct control by registering custom adapter functions.

How to write adaptable objects

Suppose we have a Point class that represents a pair of coordinates, x and y, in a Cartesian coordinate system. The coordinate pair will be stored as a text string in the database, using a semicolon to separate the coordinates. This can be implemented by adding a __conform__(self, protocol) method which returns the adapted value. The object passed to protocol will be of type PrepareProtocol.

class Point:
    def __init__(self, x, y):
        self.x, self.y = x, y

    def __conform__(self, protocol):
        if protocol is sqlite3.PrepareProtocol:
            return f"{self.x};{self.y}"

con = sqlite3.connect(":memory:")
cur = con.cursor()

cur.execute("SELECT ?", (Point(4.0, -3.2),))
print(cur.fetchone()[0])
con.close()

How to register adapter callables

The other possibility is to create a function that converts the Python object to an SQLite-compatible type. This function can then be registered using register_adapter().

class Point:
    def __init__(self, x, y):
        self.x, self.y = x, y

def adapt_point(point):
    return f"{point.x};{point.y}"

sqlite3.register_adapter(Point, adapt_point)

con = sqlite3.connect(":memory:")
cur = con.cursor()

cur.execute("SELECT ?", (Point(1.0, 2.5),))
print(cur.fetchone()[0])
con.close()

How to convert SQLite values to custom Python types

Writing an adapter lets you convert from custom Python types to SQLite values. To be able to convert from SQLite values to custom Python types, we use converters.

Let’s go back to the Point class. We stored the x and y coordinates separated via semicolons as strings in SQLite.

First, we’ll define a converter function that accepts the string as a parameter and constructs a Point object from it.

참고

Converter functions are always passed a bytes object, no matter the underlying SQLite data type.

def convert_point(s):
    x, y = map(float, s.split(b";"))
    return Point(x, y)

We now need to tell sqlite3 when it should convert a given SQLite value. This is done when connecting to a database, using the detect_types parameter of connect(). There are three options:

Implicit: set detect_types to PARSE_DECLTYPES

Explicit: set detect_types to PARSE_COLNAMES

Both: set detect_types to sqlite3.PARSE_DECLTYPES | sqlite3.PARSE_COLNAMES. Column names take precedence over declared types.

The following example illustrates the implicit and explicit approaches:

class Point:
    def __init__(self, x, y):
        self.x, self.y = x, y

    def __repr__(self):
        return f"Point({self.x}, {self.y})"

def adapt_point(point):
    return f"{point.x};{point.y}"

def convert_point(s):
    x, y = list(map(float, s.split(b";")))
    return Point(x, y)

# Register the adapter and converter
sqlite3.register_adapter(Point, adapt_point)
sqlite3.register_converter("point", convert_point)

# 1) Parse using declared types
p = Point(4.0, -3.2)
con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_DECLTYPES)
cur = con.execute("CREATE TABLE test(p point)")

cur.execute("INSERT INTO test(p) VALUES(?)", (p,))
cur.execute("SELECT p FROM test")
print("with declared types:", cur.fetchone()[0])
cur.close()
con.close()

# 2) Parse using column names
con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_COLNAMES)
cur = con.execute("CREATE TABLE test(p)")

cur.execute("INSERT INTO test(p) VALUES(?)", (p,))
cur.execute('SELECT p AS "p [point]" FROM test')
print("with column names:", cur.fetchone()[0])
cur.close()
con.close()

Adapter and converter recipes

This section shows recipes for common adapters and converters.

import datetime
import sqlite3

def adapt_date_iso(val):
    """Adapt datetime.date to ISO 8601 date."""
    return val.isoformat()

def adapt_datetime_iso(val):
    """Adapt datetime.datetime to timezone-naive ISO 8601 date."""
    return val.isoformat()

def adapt_datetime_epoch(val):
    """Adapt datetime.datetime to Unix timestamp."""
    return int(val.timestamp())

sqlite3.register_adapter(datetime.date, adapt_date_iso)
sqlite3.register_adapter(datetime.datetime, adapt_datetime_iso)
sqlite3.register_adapter(datetime.datetime, adapt_datetime_epoch)

def convert_date(val):
    """Convert ISO 8601 date to datetime.date object."""
    return datetime.date.fromisoformat(val.decode())

def convert_datetime(val):
    """Convert ISO 8601 datetime to datetime.datetime object."""
    return datetime.datetime.fromisoformat(val.decode())

def convert_timestamp(val):
    """Convert Unix epoch timestamp to datetime.datetime object."""
    return datetime.datetime.fromtimestamp(int(val))

sqlite3.register_converter("date", convert_date)
sqlite3.register_converter("datetime", convert_datetime)
sqlite3.register_converter("timestamp", convert_timestamp)

How to use connection shortcut methods

Using the execute(), executemany(), and executescript() methods of the Connection class, your code can be written more concisely because you don’t have to create the (often superfluous) Cursor objects explicitly. Instead, the Cursor objects are created implicitly and these shortcut methods return the cursor objects. This way, you can execute a SELECT statement and iterate over it directly using only a single call on the Connection object.

# Create and fill the table.
con = sqlite3.connect(":memory:")
con.execute("CREATE TABLE lang(name, first_appeared)")
data = [
    ("C++", 1985),
    ("Objective-C", 1984),
]
con.executemany("INSERT INTO lang(name, first_appeared) VALUES(?, ?)", data)

# Print the table contents
for row in con.execute("SELECT name, first_appeared FROM lang"):
    print(row)

print("I just deleted", con.execute("DELETE FROM lang").rowcount, "rows")

# close() is not a shortcut method and it's not called automatically;
# the connection object should be closed manually
con.close()

How to use the connection context manager

A Connection object can be used as a context manager that automatically commits or rolls back open transactions when leaving the body of the context manager. If the body of the with statement finishes without exceptions, the transaction is committed. If this commit fails, or if the body of the with statement raises an uncaught exception, the transaction is rolled back. If autocommit is False, a new transaction is implicitly opened after committing or rolling back.

If there is no open transaction upon leaving the body of the with statement, or if autocommit is True, the context manager does nothing.

참고

The context manager neither implicitly opens a new transaction nor closes the connection. If you need a closing context manager, consider using contextlib.closing().

con = sqlite3.connect(":memory:")
con.execute("CREATE TABLE lang(id INTEGER PRIMARY KEY, name VARCHAR UNIQUE)")

# Successful, con.commit() is called automatically afterwards
with con:
    con.execute("INSERT INTO lang(name) VALUES(?)", ("Python",))

# con.rollback() is called after the with block finishes with an exception,
# the exception is still raised and must be caught
try:
    with con:
        con.execute("INSERT INTO lang(name) VALUES(?)", ("Python",))
except sqlite3.IntegrityError:
    print("couldn't add Python twice")

# Connection object used as context manager only commits or rollbacks transactions,
# so the connection object should be closed manually
con.close()

How to work with SQLite URIs

Some useful URI tricks include:

Open a database in read-only mode:

>>> con = sqlite3.connect("file:tutorial.db?mode=ro", uri=True)
>>> con.execute("CREATE TABLE readonly(data)")
Traceback (most recent call last):
OperationalError: attempt to write a readonly database
>>> con.close()

Do not implicitly create a new database file if it does not already exist; will raise OperationalError if unable to create a new file:

>>> con = sqlite3.connect("file:nosuchdb.db?mode=rw", uri=True)
Traceback (most recent call last):
OperationalError: unable to open database file

Create a shared named in-memory database:

db = "file:mem1?mode=memory&cache=shared"
con1 = sqlite3.connect(db, uri=True)
con2 = sqlite3.connect(db, uri=True)
with con1:
    con1.execute("CREATE TABLE shared(data)")
    con1.execute("INSERT INTO shared VALUES(28)")
res = con2.execute("SELECT data FROM shared")
assert res.fetchone() == (28,)

con1.close()
con2.close()

More information about this feature, including a list of parameters, can be found in the SQLite URI documentation [https://www.sqlite.org/uri.html].

How to create and use row factories

By default, sqlite3 represents each row as a tuple. If a tuple does not suit your needs, you can use the sqlite3.Row class or a custom row_factory.

While row_factory exists as an attribute both on the Cursor and the Connection, it is recommended to set Connection.row_factory, so all cursors created from the connection will use the same row factory.

Row provides indexed and case-insensitive named access to columns, with minimal memory overhead and performance impact over a tuple. To use Row as a row factory, assign it to the row_factory attribute:

>>> con = sqlite3.connect(":memory:")
>>> con.row_factory = sqlite3.Row

Queries now return Row objects:

>>> res = con.execute("SELECT 'Earth' AS name, 6378 AS radius")
>>> row = res.fetchone()
>>> row.keys()
['name', 'radius']
>>> row[0]         # Access by index.
'Earth'
>>> row["name"]    # Access by name.
'Earth'
>>> row["RADIUS"]  # Column names are case-insensitive.
6378
>>> con.close()

참고

The FROM clause can be omitted in the SELECT statement, as in the above example. In such cases, SQLite returns a single row with columns defined by expressions, e.g. literals, with the given aliases expr AS alias.

You can create a custom row_factory that returns each row as a dict, with column names mapped to values:

def dict_factory(cursor, row):
    fields = [column[0] for column in cursor.description]
    return {key: value for key, value in zip(fields, row)}

Using it, queries now return a dict instead of a tuple:

>>> con = sqlite3.connect(":memory:")
>>> con.row_factory = dict_factory
>>> for row in con.execute("SELECT 1 AS a, 2 AS b"):
...     print(row)
{'a': 1, 'b': 2}
>>> con.close()

The following row factory returns a named tuple:

from collections import namedtuple

def namedtuple_factory(cursor, row):
    fields = [column[0] for column in cursor.description]
    cls = namedtuple("Row", fields)
    return cls._make(row)

namedtuple_factory() can be used as follows:

>>> con = sqlite3.connect(":memory:")
>>> con.row_factory = namedtuple_factory
>>> cur = con.execute("SELECT 1 AS a, 2 AS b")
>>> row = cur.fetchone()
>>> row
Row(a=1, b=2)
>>> row[0]  # Indexed access.
1
>>> row.b   # Attribute access.
2
>>> con.close()

With some adjustments, the above recipe can be adapted to use a dataclass, or any other custom class, instead of a namedtuple.

How to handle non-UTF-8 text encodings

By default, sqlite3 uses str to adapt SQLite values with the TEXT data type. This works well for UTF-8 encoded text, but it might fail for other encodings and invalid UTF-8. You can use a custom text_factory to handle such cases.

Because of SQLite’s flexible typing [https://www.sqlite.org/flextypegood.html], it is not uncommon to encounter table columns with the TEXT data type containing non-UTF-8 encodings, or even arbitrary data. To demonstrate, let’s assume we have a database with ISO-8859-2 (Latin-2) encoded text, for example a table of Czech-English dictionary entries. Assuming we now have a Connection instance con connected to this database, we can decode the Latin-2 encoded text using this text_factory:

con.text_factory = lambda data: str(data, encoding="latin2")

For invalid UTF-8 or arbitrary data in stored in TEXT table columns, you can use the following technique, borrowed from the 유니코드 HOWTO:

con.text_factory = lambda data: str(data, errors="surrogateescape")

참고

The sqlite3 module API does not support strings containing surrogates.

더 보기

유니코드 HOWTO

Explanation

Transaction control

sqlite3 offers multiple methods of controlling whether, when and how database transactions are opened and closed. Transaction control via the autocommit attribute is recommended, while Transaction control via the isolation_level attribute retains the pre-Python 3.12 behaviour.

Transaction control via the autocommit attribute

The recommended way of controlling transaction behaviour is through the Connection.autocommit attribute, which should preferably be set using the autocommit parameter of connect().

It is suggested to set autocommit to False, which implies PEP 249 [https://peps.python.org/pep-0249/]-compliant transaction control. This means:

sqlite3 ensures that a transaction is always open, so connect(), Connection.commit(), and Connection.rollback() will implicitly open a new transaction (immediately after closing the pending one, for the latter two). sqlite3 uses BEGIN DEFERRED statements when opening transactions.

Transactions should be committed explicitly using commit().

Transactions should be rolled back explicitly using rollback().

An implicit rollback is performed if the database is close()-ed with pending changes.

Set autocommit to True to enable SQLite’s autocommit mode [https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions]. In this mode, Connection.commit() and Connection.rollback() have no effect. Note that SQLite’s autocommit mode is distinct from the PEP 249 [https://peps.python.org/pep-0249/]-compliant Connection.autocommit attribute; use Connection.in_transaction to query the low-level SQLite autocommit mode.

Set autocommit to LEGACY_TRANSACTION_CONTROL to leave transaction control behaviour to the Connection.isolation_level attribute. See Transaction control via the isolation_level attribute for more information.

Transaction control via the isolation_level attribute

참고

The recommended way of controlling transactions is via the autocommit attribute. See Transaction control via the autocommit attribute.

If Connection.autocommit is set to LEGACY_TRANSACTION_CONTROL (the default), transaction behaviour is controlled using the Connection.isolation_level attribute. Otherwise, isolation_level has no effect.

If the connection attribute isolation_level is not None, new transactions are implicitly opened before execute() and executemany() executes INSERT, UPDATE, DELETE, or REPLACE statements; for other statements, no implicit transaction handling is performed. Use the commit() and rollback() methods to respectively commit and roll back pending transactions. You can choose the underlying SQLite transaction behaviour [https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions] — that is, whether and what type of BEGIN statements sqlite3 implicitly executes – via the isolation_level attribute.

If isolation_level is set to None, no transactions are implicitly opened at all. This leaves the underlying SQLite library in autocommit mode [https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions], but also allows the user to perform their own transaction handling using explicit SQL statements. The underlying SQLite library autocommit mode can be queried using the in_transaction attribute.

The executescript() method implicitly commits any pending transaction before execution of the given SQL script, regardless of the value of isolation_level.

버전 3.6에서 변경: sqlite3 used to implicitly commit an open transaction before DDL statements. This is no longer the case.

버전 3.12에서 변경: The recommended way of controlling transactions is now via the autocommit attribute.

데이터 압축 및 보관

이 장에서 설명하는 모듈은 zlib, gzip, bzip2 및 lzma 알고리즘을 사용한 데이터 압축과 ZIP- 및 tar- 형식 저장소 생성을 지원합니다. shutil 모듈에서 제공하는 아카이브 연산도 참조하십시오.

zlib — Compression compatible with gzip

error

adler32()

compress()

compressobj()

crc32()

decompress()

decompressobj()

compress()

flush()

copy()

unused_data

unconsumed_tail

eof

decompress()

flush()

copy()

ZLIB_VERSION

ZLIB_RUNTIME_VERSION

gzip — Support for gzip files

open()

BadGzipFile

GzipFile

peek()

mode

mtime

name

compress()

decompress()

사용 예

명령 줄 인터페이스

명령 줄 옵션

bz2 — Support for bzip2 compression

파일 압축(해제)

open()

BZ2File

peek()

fileno()

readable()

seekable()

writable()

read1()

readinto()

mode

name

증분 압축(해제)

BZ2Compressor

compress()

flush()

BZ2Decompressor

decompress()

eof

unused_data

needs_input

일괄 압축(해제)

compress()

decompress()

사용 예

lzma — Compression using the LZMA algorithm

LZMAError

압축 파일 읽기와 쓰기

open()

LZMAFile

peek()

mode

name

메모리에서의 데이터 압축과 압축 해제

LZMACompressor

compress()

flush()

LZMADecompressor

decompress()

check

eof

unused_data

needs_input

compress()

decompress()

기타

is_check_supported()

사용자 정의 필터 체인 지정

예

zipfile — Work with ZIP archives

BadZipFile

BadZipfile

LargeZipFile

ZipInfo

is_zipfile()

ZIP_STORED

ZIP_DEFLATED

ZIP_BZIP2

ZIP_LZMA

ZipFile 객체

ZipFile

close()

getinfo()

infolist()

namelist()

open()

extract()

extractall()

printdir()

setpassword()

read()

testzip()

write()

writestr()

mkdir()

filename

debug

comment

Path 객체

Path

name

open()

iterdir()

is_dir()

is_file()

is_symlink()

exists()

suffix

stem

suffixes

read_text()

read_bytes()

joinpath()

PyZipFile 객체

PyZipFile

writepy()

ZipInfo 객체

from_file()

is_dir()

filename

date_time

compress_type

comment

extra

create_system

create_version

extract_version

reserved

flag_bits

volume

internal_attr

external_attr

header_offset

CRC

compress_size

file_size

명령 줄 인터페이스

명령 줄 옵션

압축 해제 함정

파일 자체에서

파일 시스템 제한

자원 제한

중단

추출의 기본 동작

tarfile — Read and write tar archive files

open()

is_tarfile()

TarError

ReadError

CompressionError

StreamError

ExtractError

HeaderError

FilterError

tarinfo

AbsolutePathError

OutsideDestinationError

SpecialFileError

AbsoluteLinkError

LinkOutsideDestinationError

ENCODING

REGTYPE

AREGTYPE

LNKTYPE

SYMTYPE

CHRTYPE

BLKTYPE

DIRTYPE

FIFOTYPE

CONTTYPE

GNUTYPE_LONGNAME

GNUTYPE_LONGLINK

GNUTYPE_SPARSE

USTAR_FORMAT

GNU_FORMAT

PAX_FORMAT

DEFAULT_FORMAT

TarFile 객체

TarFile

open()

getmember()

getmembers()

getnames()

list()

next()

extractall()

extract()

extractfile()

errorlevel

extraction_filter

add()

addfile()

gettarinfo()

close()

pax_headers

TarInfo 객체

TarInfo

frombuf()

fromtarfile()

tobuf()

name

size

mtime

mode

type

linkname

uid

gid

uname

gname

chksum

devmajor

devminor

offset

offset_data

sparse

pax_headers

replace()

isfile()

isreg()

isdir()

issym()

islnk()

ischr()

isblk()

isfifo()

isdev()

Extraction filters

Default named filters

fully_trusted_filter()

tar_filter()

data_filter()

Filter errors

Hints for further verification

Supporting older Python versions

Stateful extraction filter example

명령 줄 인터페이스

명령 줄 옵션

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zlib — Compression compatible with gzip

데이터 압축이 필요한 응용 프로그램의 경우, 이 모듈의 함수는 zlib 라이브러리를 사용하여 압축과 압축 해제를 하도록 합니다. zlib 라이브러리는 https://www.zlib.net 에 자체 홈페이지가 있습니다. 파이썬 모듈과 1.1.3 이전의 zlib 라이브러리 버전 간에는 호환성 문제가 알려져 있습니다; 1.1.3에는 보안 취약점 [https://zlib.net/zlib_faq.html#faq33]이 있기 때문에, 1.1.4 이상을 사용하는 것이 좋습니다.

zlib의 함수에는 많은 옵션이 있으며 종종 특정 순서로 사용해야 합니다. 이 설명서는 모든 순열을 다루려고 시도하지는 않습니다; 권위 있는 정보는 zlib 매뉴얼(http://www.zlib.net/manual.html)을 참조하십시오.

.gz 파일 읽기와 쓰기에 대해서는 gzip 모듈을 참조하십시오.

이 모듈에서 사용 가능한 예외와 함수는 다음과 같습니다:

exception zlib.error

압축과 압축 해제 에러에서 발생하는 예외.

zlib.adler32(data[, value])

data의 Adler-32 체크섬을 계산합니다. (Adler-32 체크섬은 CRC32만큼 신뢰성 있지만, 훨씬 빠르게 계산할 수 있습니다.) 결과는 부호 없는 32비트 정수입니다. value가 있으면, 체크섬의 시작 값으로 사용됩니다; 그렇지 않으면, 기본값 1이 사용됩니다. value를 전달하면 여러 입력을 이어붙인 것에 대한 잇따른(running) 체크섬을 계산할 수 있습니다. 알고리즘은 암호학적으로 강력하지 않아서, 인증이나 디지털 서명에 사용해서는 안 됩니다. 알고리즘은 체크섬 알고리즘으로 사용하도록 설계되었으므로, 일반적인 해시 알고리즘으로 사용하기에 적합하지 않습니다.

버전 3.0에서 변경: The result is always unsigned.

zlib.compress(data, /, level=-1, wbits=MAX_WBITS)

Compresses the bytes in data, returning a bytes object containing compressed data. level is an integer from 0 to 9 or -1 controlling the level of compression; 1 (Z_BEST_SPEED) is fastest and produces the least compression, 9 (Z_BEST_COMPRESSION) is slowest and produces the most. 0 (Z_NO_COMPRESSION) is no compression. The default value is -1 (Z_DEFAULT_COMPRESSION). Z_DEFAULT_COMPRESSION represents a default compromise between speed and compression (currently equivalent to level 6).

wbits 인자는 데이터를 압축할 때 사용되는 히스토리 버퍼의 크기(또는 “창 크기(window size)”)와, 출력에 헤더와 트레일러가 포함되는지를 제어합니다. 여러 범위의 값을 취할 수 있으며, 기본값은 15(MAX_WBITS)입니다:

+9 에서 +15: 창 크기의 밑이 2인 로그, 그래서 창 크기는 512에서 32768 사이의 범위입니다. 값이 클수록 메모리 사용량이 증가하면서 압축률이 높아집니다. 결과 출력에는 zlib 특정 헤더와 트레일러가 포함됩니다.

−9 에서 −15: wbits의 절댓값을 창 크기의 로그로 사용하면서, 헤더나 후행 체크섬 없이 원시 출력 스트림을 생성합니다.

+25 에서 +31 = 16 + (9 에서 15): 하위 4비트를 창 크기의 로그로 사용하면서, 출력에 기본 gzip 헤더와 후행 체크섬을 포함합니다.

Raises the error exception if any error occurs.

버전 3.6에서 변경: level은 이제 키워드 매개 변수로 사용될 수 있습니다.

버전 3.11에서 변경: The wbits parameter is now available to set window bits and compression type.

zlib.compressobj(level=-1, method=DEFLATED, wbits=MAX_WBITS, memLevel=DEF_MEM_LEVEL, strategy=Z_DEFAULT_STRATEGY[, zdict])

메모리에 한 번에 맞지 않는 데이터 스트림을 압축하는 데 사용되는 압축 객체를 반환합니다.

level은 압축 수준입니다 – 0에서 9 또는 -1인 정수입니다. 1(Z_BEST_SPEED) 값은 가장 빠르고 압축률이 가장 낮지만, 9(Z_BEST_COMPRESSION) 값은 가장 느리고 최대 압축을 생성합니다. 0(Z_NO_COMPRESSION)은 압축하지 않습니다. 기본값은 -1(Z_DEFAULT_COMPRESSION)입니다. Z_DEFAULT_COMPRESSION은 속도와 압축률 사이의 기본 절충(현재 수준 6과 동등합니다)을 나타냅니다.

method는 압축 알고리즘입니다. 현재, 유일하게 지원되는 값은 DEFLATED입니다.

The wbits parameter controls the size of the history buffer (or the “window size”), and what header and trailer format will be used. It has the same meaning as described for compress().

memLevel 인자는 내부 압축 상태에 사용되는 메모리양을 제어합니다. 유효한 값의 범위는 1에서 9입니다. 값이 클수록 더 많은 메모리를 사용하지만, 더 빠르고 더 작은 출력을 생성합니다.

strategy는 압축 알고리즘을 조정하는 데 사용됩니다. 가능한 값은 Z_DEFAULT_STRATEGY, Z_FILTERED, Z_HUFFMAN_ONLY, Z_RLE(zlib 1.2.0.1) 및 Z_FIXED(zlib 1.2.2.2)입니다.

zdict는 사전 정의된 압축 딕셔너리입니다. 이것은 압축될 데이터에서 자주 나타날 것으로 예상되는 서브 시퀀스를 포함하는 일련의 바이트 시퀀스(가령 bytes 객체)입니다. 가장 흔할 것으로 예상되는 서브 시퀀스는 딕셔너리 끝에 와야 합니다.

버전 3.3에서 변경: zdict 매개 변수와 키워드 인자 지원이 추가되었습니다.

zlib.crc32(data[, value])

data의 CRC (Cyclic Redundancy Check) 체크섬을 계산합니다. 결과는 부호 없는 32비트 정수입니다. value가 있으면, 체크섬의 시작 값으로 사용됩니다; 그렇지 않으면, 기본값 1이 사용됩니다. value를 전달하면 여러 입력을 이어붙인 것에 대한 잇따른(running) 체크섬을 계산할 수 있습니다. 알고리즘은 암호학적으로 강력하지 않아서, 인증이나 디지털 서명에 사용해서는 안 됩니다. 알고리즘은 체크섬 알고리즘으로 사용하도록 설계되었으므로, 일반적인 해시 알고리즘으로 사용하기에 적합하지 않습니다.

버전 3.0에서 변경: The result is always unsigned.

zlib.decompress(data, /, wbits=MAX_WBITS, bufsize=DEF_BUF_SIZE)

data에 있는 바이트열을 압축 해제하여, 압축되지 않은 데이터를 포함하는 바이트열 객체를 반환합니다. wbits 매개 변수는 data의 형식에 따라 다르며, 아래에서 자세히 설명합니다. bufsize가 제공되면, 출력 버퍼의 초기 크기로 사용됩니다. 에러가 발생하면 error 예외를 발생시킵니다.

wbits 인자는 히스토리 버퍼의 크기(또는 “창 크기(window size)”)와, 어떤 헤더와 트레일러 형식을 기대하는지를 제어합니다. compressobj()의 매개 변수와 유사하지만, 더 많은 범위의 값을 받아들입니다:

+8 에서 +15: 창 크기의 밑이 2인 로그. 입력은 zlib 헤더와 트레일러를 포함해야 합니다.

0: zlib 헤더에서 창 크기를 자동으로 결정합니다. zlib 1.2.3.5부터 지원됩니다.

−8 에서 −15: wbits의 절댓값을 창 크기의 로그로 사용합니다. 입력은 헤더나 트레일러가 없는 원시 스트림이어야 합니다.

+24 에서 +31 = 16 + (8 에서 15): 값의 하위 4비트를 창 크기의 로그로 사용합니다. 입력은 gzip 헤더와 트레일러를 포함해야 합니다.

+40 에서 +47 = 32 + (8 에서 15): 값의 하위 4비트를 창 크기의 로그로 사용하고, zlib나 gzip 형식을 자동으로 받아들입니다.

스트림을 압축 해제할 때, 창 크기는 스트림을 압축하는 데 원래 사용된 크기보다 작아서는 안 됩니다; 너무 작은 값을 사용하면 error 예외가 발생할 수 있습니다. 기본 wbits 값은 가장 큰 창 크기에 해당하며 zlib 헤더와 트레일러가 포함될 것을 요구합니다.

bufsize는 압축 해제된 데이터를 담는 데 사용되는 버퍼의 초기 크기입니다. 더 많은 공간이 필요하면, 필요에 따라 버퍼 크기가 증가하므로, 이 값을 정확하게 얻을 필요는 없습니다; 조정하면 malloc()에 대한 몇 번의 호출만 절약됩니다.

버전 3.6에서 변경: wbits와 bufsize는 키워드 인자로 사용할 수 있습니다.

zlib.decompressobj(wbits=MAX_WBITS[, zdict])

메모리에 한 번에 맞지 않는 데이터 스트림을 압축 해제하는 데 사용되는 압축 해제 객체를 반환합니다.

wbits 인자는 히스토리 버퍼의 크기(또는 “창 크기(window size)”)와, 어떤 헤더와 트레일러 형식을 기대하는지를 제어합니다. decompress()에서 설명된 것과 같은 의미입니다.

zdict 매개 변수는 사전 정의된 압축 딕셔너리를 지정합니다. 제공되면,, 압축 해제할 데이터를 생성한 압축기에서 사용한 것과 같은 딕셔너리이어야 합니다.

참고

zdict가 가변 객체(가령 bytearray)이면, decompressobj()에 대한 호출과 압축 해제기의 decompress() 메서드에 대한 첫 번째 호출 사이에 내용을 수정해서는 안 됩니다.

버전 3.3에서 변경: zdict 매개 변수를 추가했습니다.

압축 객체는 다음 메서드를 지원합니다:

Compress.compress(data)

data를 압축하여, data의 데이터 중 적어도 일부에 대한 압축된 데이터가 포함된 바이트열 객체를 반환합니다. 이 데이터는 compress() 메서드에 대한 이전 호출에서 생성된 출력에 이어붙여야 합니다. 일부 입력은 나중에 처리하기 위해 내부 버퍼에 보관될 수 있습니다.

Compress.flush([mode])

계류 중인 모든 입력이 처리되고, 나머지 압축 출력을 포함하는 바이트열 객체가 반환됩니다. mode는 상수 Z_NO_FLUSH, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, Z_FULL_FLUSH, Z_BLOCK(zlib 1.2.3.4) 또는 Z_FINISH에서 선택할 수 있으며, 기본값은 Z_FINISH입니다. Z_FINISH를 제외한 모든 상수는 추가 바이트열 데이터를 압축하도록 허락하는 반면, Z_FINISH는 압축된 스트림을 완료하고 추가 데이터의 압축을 방지합니다. mode를 Z_FINISH로 설정하고 flush()를 호출한 후, compress() 메서드를 다시 호출할 수 없습니다; 유일한 현실적인 조치는 객체를 삭제하는 것입니다.

Compress.copy()

압축 객체의 복사본을 반환합니다. 공통 초기 접두사를 공유하는 데이터 집합을 효율적으로 압축하는 데 사용할 수 있습니다.

버전 3.8에서 변경: 압축 객체에 copy.copy()와 copy.deepcopy() 지원이 추가되었습니다.

압축 해제 객체는 다음과 같은 메서드와 어트리뷰트를 지원합니다:

Decompress.unused_data

압축된 데이터가 끝난 뒤의 바이트를 포함하는 바이트열 객체. 즉, 압축 데이터가 들어 있는 마지막 바이트를 사용할 수 있을 때까지 b""로 남습니다. 전체 바이트열이 압축된 데이터를 포함하는 것으로 판명되면, 이것은 빈 바이트열 객체인 b""입니다.

Decompress.unconsumed_tail

압축되지 않은 데이터 버퍼의 한계를 초과하기 때문에 마지막 decompress() 호출에 의해 소비되지 않은 모든 데이터를 포함하는 바이트열 객체. 이 데이터는 아직 zlib 장치가 볼 수 없었기 때문에 올바른 출력을 얻으려면 후속 decompress() 메서드 호출에 다시 공급해야 합니다 (아마도 추가 데이터를 이것에 이어붙여서).

Decompress.eof

압축된 데이터 스트림의 끝에 도달했는지를 나타내는 불리언.

This makes it possible to distinguish between a properly formed compressed stream, and an incomplete or truncated one.

Added in version 3.3.

Decompress.decompress(data, max_length=0)

data를 압축 해제하여, string의 데이터 중 적어도 일부에 해당하는 압축되지 않은 데이터를 포함하는 바이트열 객체를 반환합니다. 이 데이터는 decompress() 메서드에 대한 이전 호출에서 생성된 출력에 이어붙여야 합니다. 입력 데이터 중 일부는 나중에 처리하기 위해 내부 버퍼에 보존될 수 있습니다.

선택적 매개 변수 max_length가 0이 아니면 반환 값은 max_length보다 길지 않습니다. 이는 모든 압축 입력을 처리할 수 없음을 뜻합니다; 소비되지 않은 데이터는 unconsumed_tail 어트리뷰트에 저장됩니다. 압축 해제를 계속하려면 이 바이트열을 decompress()에 대한 후속 호출로 전달해야 합니다. max_length가 0이면 전체 입력이 압축 해제되고, unconsumed_tail은 비어 있습니다.

버전 3.6에서 변경: max_length는 키워드 인자로 사용할 수 있습니다.

Decompress.flush([length])

계류 중인 모든 입력이 처리되고, 나머지 압축되지 않은 출력을 포함하는 바이트열 객체가 반환됩니다. flush()를 호출한 후, decompress() 메서드를 다시 호출할 수 없습니다; 유일한 현실적인 조치는 객체를 삭제하는 것입니다.

선택적 매개 변수 length는 출력 버퍼의 초기 크기를 설정합니다.

Decompress.copy()

압축 해제 객체의 복사본을 반환합니다. 이것은 미래 시점에 스트림으로의 임의 탐색(random seek) 속도를 높이기 위해 데이터 스트림의 중간 지점에서 압축 해제기의 상태를 저장하는 데 사용될 수 있습니다.

버전 3.8에서 변경: 압축 해제 객체에 copy.copy()와 copy.deepcopy() 지원이 추가되었습니다.

사용 중인 zlib 라이브러리 버전에 대한 정보는 다음 상수를 통해 사용할 수 있습니다:

zlib.ZLIB_VERSION

모듈을 빌드하는 데 사용된 zlib 라이브러리의 버전 문자열. ZLIB_RUNTIME_VERSION으로 사용 가능한, 실행 시간에 실제로 사용되는 zlib 라이브러리와 다를 수 있습니다.

zlib.ZLIB_RUNTIME_VERSION

인터프리터가 실제로 로드한 zlib 라이브러리의 버전 문자열.

Added in version 3.3.

더 보기

모듈 gzip

gzip 형식 파일 읽기와 쓰기

http://www.zlib.net

zlib 라이브러리 홈페이지.

http://www.zlib.net/manual.html

zlib 매뉴얼은 라이브러리의 많은 함수의 의미와 사용법을 설명합니다.

gzip — Support for gzip files

소스 코드: Lib/gzip.py [https://github.com/python/cpython/tree/main/Lib/gzip.py]

이 모듈은 GNU 프로그램 gzip과 gunzip처럼 파일을 압축하고 압축을 푸는 간단한 인터페이스를 제공합니다.

데이터 압축은 zlib 모듈에 의해 제공됩니다.

gzip 모듈은 open(), compress() 및 decompress() 편리 함수뿐만 아니라 GzipFile 클래스도 제공합니다. GzipFile 클래스는 gzip-형식 파일을 읽고 쓰는데, 자동으로 데이터를 압축하거나 압축을 풀어서 일반적인 파일 객체처럼 보이게 합니다.

compress와 pack 프로그램에서 생성된 것과 같은, gzip과 gunzip 프로그램으로 압축을 풀 수 있는 추가 파일 형식은 이 모듈에서 지원하지 않습니다.

이 모듈은 다음 항목을 정의합니다:

gzip.open(filename, mode='rb', compresslevel=9, encoding=None, errors=None, newline=None)

바이너리나 텍스트 모드로 gzip으로 압축된 파일을 열고, 파일 객체를 반환합니다.

filename 인자는 실제 파일명(str이나 bytes 객체)이나, 읽거나 쓸 기존 파일 객체가 될 수 있습니다.

mode 인자는 바이너리 모드의 경우 'r', 'rb', 'a', 'ab', 'w', 'wb', 'x' 또는 'xb', 또는 텍스트 모드의 경우 'rt', 'at', 'wt' 또는 'xt' 중 하나일 수 있습니다. 기본값은 'rb'입니다.

compresslevel 인자는 GzipFile 생성자와 마찬가지로 0에서 9 사이의 정수입니다.

바이너리 모드의 경우, 이 함수는 GzipFile 생성자 GzipFile(filename, mode, compresslevel)와 동등합니다. 이 경우, encoding, errors 및 newline 인자를 제공하면 안 됩니다.

텍스트 모드의 경우, GzipFile 객체가 만들어지고, 지정된 인코딩, 에러 처리 동작 및 줄 종료를 갖는 io.TextIOWrapper 인스턴스로 감싸집니다.

버전 3.3에서 변경: 파일 객체인 filename 지원, 텍스트 모드 지원 및 encoding, errors 및 newline 인자가 추가되었습니다.

버전 3.4에서 변경: 'x', 'xb' 및 'xt' 모드에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

exception gzip.BadGzipFile

An exception raised for invalid gzip files. It inherits from OSError. EOFError and zlib.error can also be raised for invalid gzip files.

Added in version 3.8.

class gzip.GzipFile(filename=None, mode=None, compresslevel=9, fileobj=None, mtime=None)

Constructor for the GzipFile class, which simulates most of the methods of a file object, with the exception of the truncate() method. At least one of fileobj and filename must be given a non-trivial value.

새 클래스 인스턴스는 fileobj를 기반으로 하는데, 일반 파일, io.BytesIO 객체 또는 파일을 흉내 내는 다른 객체가 될 수 있습니다. 기본값은 None이며, 이 경우 파일 객체를 제공하기 위해 filename이 열립니다.

fileobj가 None이 아닐 때, filename 인자는 gzip 파일 헤더에 포함되는 데만 사용되며, 이 헤더에는 압축되지 않은 파일의 원래 파일명이 포함될 수 있습니다. 보고 알 수 있다면, fileobj의 파일명을 기본값으로 사용합니다; 그렇지 않으면, 기본값은 빈 문자열이며, 이 경우 원래 파일명은 헤더에 포함되지 않습니다.

mode 인자는 파일을 읽을지 쓸지에 따라 'r', 'rb', 'a', 'ab', 'w', 'wb', 'x' 또는 'xb' 중 하나일 수 있습니다. 보고 알 수 있다면, 기본값은 fileobj의 모드입니다; 그렇지 않으면, 기본값은 'rb'입니다. 향후 파이썬 릴리스에서는 fileobj의 모드가 사용되지 않습니다. 항상 쓰기를 위해서는 mode를 지정하는 것이 좋습니다.

파일이 항상 바이너리 모드로 열림에 유의하십시오. 텍스트 모드로 압축 파일을 열려면, open()을 사용하십시오 (또는 GzipFile을 io.TextIOWrapper로 감싸십시오).

compresslevel 인자는 압축 수준을 제어하는 0에서 9까지의 정수입니다; 1은 가장 빠르고 압축률이 가장 낮으며, 9는 가장 느리고 압축률이 가장 높습니다. 0은 압축하지 않습니다. 기본값은 9입니다.

The optional mtime argument is the timestamp requested by gzip. The time is in Unix format, i.e., seconds since 00:00:00 UTC, January 1, 1970. If mtime is omitted or None, the current time is used. Use mtime = 0 to generate a compressed stream that does not depend on creation time.

See below for the mtime attribute that is set when decompressing.

Calling a GzipFile object’s close() method does not close fileobj, since you might wish to append more material after the compressed data. This also allows you to pass an io.BytesIO object opened for writing as fileobj, and retrieve the resulting memory buffer using the io.BytesIO object’s getvalue() method.

GzipFile supports the io.BufferedIOBase interface, including iteration and the with statement. Only the truncate() method isn’t implemented.

GzipFile은 다음 메서드와 어트리뷰트도 제공합니다:

peek(n)

파일 위치를 전진시키지 않고 압축되지 않은 n 바이트를 읽습니다. 호출을 만족시키기 위해 압축된 스트림에 대해 최대 한 번의 읽기가 수행됩니다. 반환된 바이트 수는 요청한 것보다 많거나 적을 수 있습니다.

참고

peek()를 호출할 때 GzipFile의 파일 위치가 변경되지는 않지만, 하부 파일 객체의 위치는 변경될 수 있습니다 (예를 들어, GzipFile이 fileobj 매개 변수로 생성된 경우).

Added in version 3.2.

mode

'rb' for reading and 'wb' for writing.

버전 3.13에서 변경: In previous versions it was an integer 1 or 2.

mtime

When decompressing, this attribute is set to the last timestamp in the most recently read header. It is an integer, holding the number of seconds since the Unix epoch (00:00:00 UTC, January 1, 1970). The initial value before reading any headers is None.

name

The path to the gzip file on disk, as a str or bytes. Equivalent to the output of os.fspath() on the original input path, with no other normalization, resolution or expansion.

버전 3.1에서 변경: mtime 생성자 인자와 mtime 어트리뷰트와 함께 with 문에 대한 지원이 추가되었습니다.

버전 3.2에서 변경: 제로 패딩(zero-padded)된 파일과 위치 변경할 수 없는(unseekable) 파일에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: io.BufferedIOBase.read1() 메서드가 이제 구현됩니다.

버전 3.4에서 변경: 'x' 및 'xb' 모드에 대한 지원이 추가되었습니다.

버전 3.5에서 변경: 임의의 바이트열류 객체를 쓰는 지원이 추가되었습니다. 이제 read() 메서드는 None 인자를 받아들입니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.9부터 폐지됨: mode 인자를 지정하지 않고 쓰기 위해 GzipFile을 여는 것은 폐지되었습니다.

버전 3.12에서 변경: Remove the filename attribute, use the name attribute instead.

gzip.compress(data, compresslevel=9, *, mtime=0)

Compress the data, returning a bytes object containing the compressed data. compresslevel and mtime have the same meaning as in the GzipFile constructor above, but mtime defaults to 0 for reproducible output.

Added in version 3.2.

버전 3.8에서 변경: 재현성 있는 출력을 위한 mtime 매개 변수가 추가되었습니다.

버전 3.11에서 변경: Speed is improved by compressing all data at once instead of in a streamed fashion. Calls with mtime set to 0 are delegated to zlib.compress() for better speed. In this situation the output may contain a gzip header “OS” byte value other than 255 “unknown” as supplied by the underlying zlib implementation.

버전 3.13에서 변경: The gzip header OS byte is guaranteed to be set to 255 when this function is used as was the case in 3.10 and earlier.

버전 3.14에서 변경: The mtime parameter now defaults to 0 for reproducible output. For the previous behaviour of using the current time, pass None to mtime.

gzip.decompress(data)

Decompress the data, returning a bytes object containing the uncompressed data. This function is capable of decompressing multi-member gzip data (multiple gzip blocks concatenated together). When the data is certain to contain only one member the zlib.decompress() function with wbits set to 31 is faster.

Added in version 3.2.

버전 3.11에서 변경: Speed is improved by decompressing members at once in memory instead of in a streamed fashion.

사용 예

압축된 파일을 읽는 방법의 예:

import gzip
with gzip.open('/home/joe/file.txt.gz', 'rb') as f:
    file_content = f.read()

압축된 GZIP 파일을 만드는 방법의 예:

import gzip
content = b"Lots of content here"
with gzip.open('/home/joe/file.txt.gz', 'wb') as f:
    f.write(content)

기존 파일을 GZIP 압축하는 방법의 예:

import gzip
import shutil
with open('/home/joe/file.txt', 'rb') as f_in:
    with gzip.open('/home/joe/file.txt.gz', 'wb') as f_out:
        shutil.copyfileobj(f_in, f_out)

바이너리 문자열을 GZIP 압축하는 방법의 예:

import gzip
s_in = b"Lots of content here"
s_out = gzip.compress(s_in)

더 보기

모듈 zlib

gzip 파일 형식을 지원하는 데 필요한 기본 데이터 압축 모듈.

명령 줄 인터페이스

gzip 모듈은 파일을 압축하거나 압축 해제하는 간단한 명령 줄 인터페이스를 제공합니다.

일단 실행되면 gzip 모듈은 입력 파일을 유지합니다.

버전 3.8에서 변경: 새로운 명령 중 인터페이스를 사용법과 함께 추가합니다. 기본적으로, CLI를 실행할 때, 기본 압축 수준은 6입니다.

명령 줄 옵션

file

If file is not specified, read from sys.stdin.

--fast

가장 빠른 압축 방법(압축을 덜 함)을 나타냅니다.

--best

가장 느린 압축 방법(최상의 압축)을 나타냅니다.

-d, --decompress

주어진 파일의 압축을 풉니다.

-h, --help

도움말 메시지를 표시합니다.

bz2 — Support for bzip2 compression

소스 코드: Lib/bz2.py [https://github.com/python/cpython/tree/main/Lib/bz2.py]

이 모듈은 bzip2 압축 알고리즘을 사용하여 데이터 압축과 압축 해제를 위한 포괄적인 인터페이스를 제공합니다.

bz2 모듈에는 다음이 포함됩니다:

압축된 파일을 읽고 쓰기 위한 open() 함수와 BZ2File 클래스.

증분 압축(해제)을 위한 BZ2Compressor와 BZ2Decompressor 클래스.

일괄 압축(해제)을 위한 compress()와 decompress() 함수.

파일 압축(해제)

bz2.open(filename, mode='rb', compresslevel=9, encoding=None, errors=None, newline=None)

바이너리나 텍스트 모드로 bzip2 압축된 파일을 열고, 파일 객체를 반환합니다.

BZ2File의 생성자와 마찬가지로, filename 인자는 실제 파일명(str이나 bytes 객체)이거나, 읽거나 쓸 기존 파일 객체가 될 수 있습니다.

mode 인자는 바이너리 모드의 경우 'r', 'rb', 'w', 'wb', 'x', 'xb', 'a' 또는 'ab', 또는 텍스트 모드의 경우 'rt', 'wt', 'xt' 또는 'at' 중 하나일 수 있습니다. 기본값은 'rb'입니다.

compresslevel 인자는 BZ2File 생성자와 마찬가지로 1에서 9 사이의 정수입니다.

바이너리 모드의 경우, 이 함수는 BZ2File 생성자 BZ2File(filename, mode, compresslevel=compresslevel)와 동등합니다. 이 경우, encoding, errors 및 newline 인자를 제공하면 안 됩니다.

텍스트 모드의 경우, BZ2File 객체가 만들어지고, 지정된 인코딩, 에러 처리 동작 및 줄 종료를 갖는 io.TextIOWrapper 인스턴스로 감싸집니다.

Added in version 3.3.

버전 3.4에서 변경: 'x' (배타적 생성) 모드가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

class bz2.BZ2File(filename, mode='r', *, compresslevel=9)

바이너리 모드로 bzip2 압축된 파일을 엽니다.

filename이 str이나 bytes 객체면, 명명된 파일을 직접 엽니다. 그렇지 않으면, filename은 파일 객체 여야 하며, 압축된 데이터를 읽거나 쓰는 데 사용됩니다.

mode 인자는 읽기를 위한 'r' (기본값), 덮어쓰기를 위한 'w', 배타적 생성을 위한 'x' 또는 덧붙이기를 위한 'a' 중 하나일 수 있습니다. 이들은 각각 'rb', 'wb', 'xb' 및 'ab'로 주어지는 것과 동등합니다.

filename이 (실제 파일 이름 대신) 파일 객체면, 'w' 모드는 파일을 자르지 않으며, 대신 'a'와 동등합니다.

mode가 'w'나 'a'이면, compresslevel은 압축 수준을 지정하는 1과 9 사이의 정수일 수 있습니다: 1은 압축률이 가장 낮고, 9(기본값)는 압축률이 가장 높습니다.

mode가 'r'이면, 입력 파일은 여러 개의 압축된 스트림을 이어 붙인 것일 수 있습니다.

BZ2File provides all of the members specified by the io.BufferedIOBase, except for detach() and truncate(). Iteration and the with statement are supported.

BZ2File also provides the following methods and attributes:

peek([n])

파일 위치를 전진시키지 않고 버퍼링 된 데이터를 반환합니다. (EOF에 있지 않은 한) 적어도 1바이트의 데이터가 반환됩니다. 반환되는 정확한 바이트 수는 지정되지 않습니다.

참고

peek()를 호출할 때 BZ2File의 파일 위치가 변경되지는 않지만, 하부 파일 객체의 위치는 변경될 수 있습니다 (예를 들어, BZ2File이 filename에 파일 객체를 전달하여 생성된 경우).

Added in version 3.3.

fileno()

Return the file descriptor for the underlying file.

Added in version 3.3.

readable()

Return whether the file was opened for reading.

Added in version 3.3.

seekable()

Return whether the file supports seeking.

Added in version 3.3.

writable()

Return whether the file was opened for writing.

Added in version 3.3.

read1(size=-1)

Read up to size uncompressed bytes, while trying to avoid making multiple reads from the underlying stream. Reads up to a buffer’s worth of data if size is negative.

Returns b'' if the file is at EOF.

Added in version 3.3.

readinto(b)

Read bytes into b.

Returns the number of bytes read (0 for EOF).

Added in version 3.3.

mode

'rb' for reading and 'wb' for writing.

Added in version 3.13.

name

The bzip2 file name. Equivalent to the name attribute of the underlying file object.

Added in version 3.13.

버전 3.1에서 변경: with 문에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: 실제 파일명 대신 파일 객체 인 filename에 대한 지원이 추가되었습니다.

다중 스트림 파일 읽기 지원과 함께, 'a' (덧붙이기) 모드가 추가되었습니다.

버전 3.4에서 변경: 'x' (배타적 생성) 모드가 추가되었습니다.

버전 3.5에서 변경: read() 메서드는 이제 None 인자를 받아들입니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.9에서 변경: buffering 매개 변수가 제거되었습니다. 파이썬 3.0부터 무시되고 폐지되었습니다. 파일을 여는 방법을 제어하려면 열린 파일 객체를 전달하십시오.

compresslevel 매개 변수가 키워드 전용이 되었습니다.

버전 3.10에서 변경: This class is thread unsafe in the face of multiple simultaneous readers or writers, just like its equivalent classes in gzip and lzma have always been.

증분 압축(해제)

class bz2.BZ2Compressor(compresslevel=9)

새로운 압축기 객체를 만듭니다. 이 객체는 증분 적으로(incrementally) 데이터를 압축하는 데 사용될 수 있습니다. 일괄(one-shot) 압축에는, 대신 compress() 함수를 사용하십시오.

주어진다면, compresslevel은 1과 9 사이의 정수여야 합니다. 기본값은 9입니다.

compress(data)

압축기 객체에 데이터를 제공합니다. 가능하면 압축된 데이터 청크를 반환하고, 그렇지 않으면 빈 바이트열을 반환합니다.

압축기에 데이터 제공이 끝나면, flush() 메서드를 호출하여 압축 공정을 마무리하십시오.

flush()

압축 공정을 마칩니다. 내부 버퍼에 남아있는 압축된 데이터를 반환합니다.

이 메서드가 호출된 후에는, 압축기 객체를 사용할 수 없습니다.

class bz2.BZ2Decompressor

새로운 압축 해제기 객체를 만듭니다. 이 객체는 데이터를 증분 적으로 압축 해제하는 데 사용될 수 있습니다. 일괄 압축에는, 대신 decompress() 함수를 사용하십시오.

참고

이 클래스는 decompress()와 BZ2File과 달리 다중 압축 스트림을 포함하는 입력을 투명하게 처리하지 않습니다. BZ2Decompressor로 다중 스트림 입력의 압축을 풀어야 한다면, 각 스트림 마다 새 압축 해제기를 사용해야 합니다.

decompress(data, max_length=-1)

data(바이트열류 객체)의 압축을 풀고, 압축되지 않은 데이터를 바이트열로 반환합니다. 일부 data는 나중에 decompress()를 호출할 때 사용할 수 있도록 내부에 버퍼링 됩니다. 반환된 데이터는 decompress()에 대한 이전 호출의 출력에 이어붙여야 합니다.

max_length가 음수가 아니면, 최대 max_length 바이트의 압축 해제된 데이터를 반환합니다. 이 제한에 도달했고, 추가 출력을 생성할 수 없으면, needs_input 어트리뷰트는 False로 설정됩니다. 이때, decompress()에 대한 다음 호출은 출력을 더 얻기 위해 data를 b''로 제공할 수 있습니다.

입력 데이터가 모두 압축 해제되고 반환되었으면 (max_length 바이트 미만이거나 max_length가 음수라서), needs_input 어트리뷰트가 True로 설정됩니다.

Attempting to decompress data after the end of stream is reached raises an EOFError. Any data found after the end of the stream is ignored and saved in the unused_data attribute.

버전 3.5에서 변경: max_length 매개 변수가 추가되었습니다.

eof

스트림의 끝(end-of-stream) 마커에 도달했으면 True.

Added in version 3.3.

unused_data

압축된 스트림의 끝 이후에 발견된 데이터.

스트림의 끝에 도달하기 전에 이 어트리뷰트를 액세스하면, 값은 b''가 됩니다.

needs_input

decompress() 메서드가 새로운 압축된 입력을 요구하기 전에 압축 해제된 데이터를 더 제공할 수 있으면 False.

Added in version 3.5.

일괄 압축(해제)

bz2.compress(data, compresslevel=9)

비이트열류 객체, data를 압축합니다.

주어진다면, compresslevel은 1과 9 사이의 정수여야 합니다. 기본값은 9입니다.

증분 압축에는, 대신 BZ2Compressor를 사용하십시오.

bz2.decompress(data)

비이트열류 객체, data를 압축 해제합니다.

data가 다중 압축 스트림을 이어붙인 것이면, 모든 스트림의 압축을 풉니다.

증분 압축 해제에는, 대신 BZ2Decompressor를 사용하십시오.

버전 3.3에서 변경: 다중 스트림 입력에 대한 지원이 추가되었습니다.

사용 예

다음은 bz2 모듈의 일반적인 사용법에 대한 몇 가지 예입니다.

왕복 압축을 시연하기 위해 compress()와 decompress() 사용하기:

>>> import bz2
>>> data = b"""\
... Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue
... nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,
... sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus
... pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.
... Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo
... felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum
... dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""
>>> c = bz2.compress(data)
>>> len(data) / len(c)  # Data compression ratio
1.513595166163142
>>> d = bz2.decompress(c)
>>> data == d  # Check equality to original object after round-trip
True

증분 압축을 위한 BZ2Compressor 사용하기:

>>> import bz2
>>> def gen_data(chunks=10, chunksize=1000):
...     """Yield incremental blocks of chunksize bytes."""
...     for _ in range(chunks):
...         yield b"z" * chunksize
...
>>> comp = bz2.BZ2Compressor()
>>> out = b""
>>> for chunk in gen_data():
...     # Provide data to the compressor object
...     out = out + comp.compress(chunk)
...
>>> # Finish the compression process.  Call this once you have
>>> # finished providing data to the compressor.
>>> out = out + comp.flush()

The example above uses a very “nonrandom” stream of data (a stream of b"z" chunks). Random data tends to compress poorly, while ordered, repetitive data usually yields a high compression ratio.

바이너리 모드로 bzip2 압축된 파일을 쓰고 읽기:

>>> import bz2
>>> data = b"""\
... Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue
... nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,
... sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus
... pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.
... Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo
... felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum
... dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""
>>> with bz2.open("myfile.bz2", "wb") as f:
...     # Write compressed data to file
...     unused = f.write(data)
...
>>> with bz2.open("myfile.bz2", "rb") as f:
...     # Decompress data from file
...     content = f.read()
...
>>> content == data  # Check equality to original object after round-trip
True

lzma — Compression using the LZMA algorithm

Added in version 3.3.

소스 코드: Lib/lzma.py [https://github.com/python/cpython/tree/main/Lib/lzma.py]

이 모듈은 LZMA 압축 알고리즘을 사용하여 데이터를 압축 및 압축 해제하기 위한 클래스와 편의 함수를 제공합니다. 또한 xz 유틸리티에서 사용되는 .xz와 레거시 .lzma 파일 형식뿐만 아니라 원시 압축 스트림을 지원하는 파일 인터페이스도 포함되어 있습니다.

The interface provided by this module is very similar to that of the bz2 module. Note that LZMAFile and bz2.BZ2File are not thread-safe, so if you need to use a single LZMAFile instance from multiple threads, it is necessary to protect it with a lock.

exception lzma.LZMAError

이 예외는 압축이나 압축 해제 중, 또는 압축기/압축 해제기 상태를 초기화하는 동안 에러가 발생할 때 발생합니다.

압축 파일 읽기와 쓰기

lzma.open(filename, mode='rb', *, format=None, check=-1, preset=None, filters=None, encoding=None, errors=None, newline=None)

바이너리나 텍스트 모드에서 LZMA 압축 파일을 열고, 파일 객체를 반환합니다.

filename 인자는 실제 파일 이름(str, bytes 또는 경로류 객체로 제공됩니다)일 수 있고, 이때는 명명된 파일이 열립니다. 또는 읽거나 쓸 기존 파일 객체일 수 있습니다.

mode 인자는 바이너리 모드의 경우 "r", "rb", "w", "wb", "x", "xb", "a" 또는 "ab"이거나, 텍스트 모드의 경우 "rt", "wt", "xt" 또는 "at" 일 수 있습니다. 기본값은 "rb"입니다.

파일을 읽기 위해 열 때, format과 filters 인자는 LZMADecompressor와 같은 의미입니다. 이 경우, check과 preset 인자를 사용하지 않아야 합니다.

파일을 쓰기 위해 열 때, format, check, preset 및 filters 인자는 LZMACompressor와 같은 의미입니다.

바이너리 모드의 경우, 이 함수는 LZMAFile 생성자와 동등합니다: LZMAFile(filename, mode, ...). 이 경우, encoding, errors 및 newline 인자는 제공하지 않아야 합니다.

텍스트 모드의 경우, LZMAFile 객체가 만들어지고, 지정된 인코딩, 에러 처리 동작 및 줄 종료로 io.TextIOWrapper 인스턴스로 감쌉니다.

버전 3.4에서 변경: "x", "xb" 및 "xt" 모드에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 허용합니다.

class lzma.LZMAFile(filename=None, mode='r', *, format=None, check=-1, preset=None, filters=None)

바이너리 모드로 LZMA 압축 파일을 엽니다.

LZMAFile은 이미 열려있는 파일 객체를 래핑하거나, 명명된 파일에 직접 작용할 수 있습니다. filename 인자는 래핑할 파일 객체나 열 파일의 이름(str, bytes 또는 경로류 객체로)을 지정합니다. 기존 파일 객체를 래핑할 때, 래핑 된 파일은 LZMAFile이 닫힐 때 닫히지 않습니다.

mode 인자는 읽기 위한 "r" (기본값), 덮어쓰기 위한 "w", 배타적 생성을 위한 "x" 또는 덧붙이기를 위한 "a" 일 수 있습니다. 이들은 각각 "rb", "wb", "xb" 및 "ab"로 동등하게 제공될 수 있습니다.

filename이 (실제 파일 이름이 아닌) 파일 객체이면, "w" 모드는 파일을 자르지 않으며, 대신 "a"와 동등합니다.

읽기 위해 파일을 열 때, 입력 파일은 여러 개의 개별 압축 스트림을 연결한 것일 수 있습니다. 이들은 단일 논리 스트림으로 투명하게 디코딩됩니다.

파일을 읽기 위해 열 때, format과 filters 인자는 LZMADecompressor와 같은 의미입니다. 이 경우, check과 preset 인자를 사용하지 않아야 합니다.

파일을 쓰기 위해 열 때, format, check, preset 및 filters 인자는 LZMACompressor와 같은 의미입니다.

LZMAFile supports all the members specified by io.BufferedIOBase, except for detach() and truncate(). Iteration and the with statement are supported.

The following method and attributes are also provided:

peek(size=-1)

파일 위치를 진행하지 않고 버퍼링 된 데이터를 반환합니다. EOF에 도달하지 않았으면, 최소 1바이트의 데이터가 반환됩니다. 반환되는 정확한 바이트 수는 지정되지 않습니다 (size 인자는 무시됩니다).

참고

peek()를 호출해도 LZMAFile의 파일 위치는 변경되지 않지만, 하부 파일 객체의 위치는 변경될 수 있습니다 (예를 들어 LZMAFile이 filename으로 파일 객체를 전달하여 생성되었을 때).

mode

'rb' for reading and 'wb' for writing.

Added in version 3.13.

name

The lzma file name. Equivalent to the name attribute of the underlying file object.

Added in version 3.13.

버전 3.4에서 변경: "x"와 "xb" 모드에 대한 지원이 추가되었습니다.

버전 3.5에서 변경: read() 메서드는 이제 None 인자를 허용합니다.

버전 3.6에서 변경: 경로류 객체를 허용합니다.

메모리에서의 데이터 압축과 압축 해제

class lzma.LZMACompressor(format=FORMAT_XZ, check=-1, preset=None, filters=None)

데이터를 증분 압축하는 데 사용할 수 있는 압축기 객체를 만듭니다.

단일 데이터 청크를 압축하는 더 편리한 방법은, compress()를 참조하십시오.

format 인자는 사용해야 할 컨테이너 형식을 지정합니다. 가능한 값은 다음과 같습니다:

FORMAT_XZ: .xz 컨테이너 형식.

이것이 기본 형식입니다.

FORMAT_ALONE: 레거시 .lzma 컨테이너 형식.

이 형식은 .xz보다 제한적입니다 – 무결성 검사나 다중 필터를 지원하지 않습니다.

FORMAT_RAW: 컨테이너 형식을 사용하지 않는 원시 데이터 스트림.

이 형식 지정자는 무결성 검사를 지원하지 않으며, 항상 사용자 지정 필터 체인(압축과 압축 해제 모두를 위한)을 지정해야 합니다. 또한, 이 방식으로 압축된 데이터는 FORMAT_AUTO를 사용하여 압축 해제할 수 없습니다 (LZMADecompressor를 참조하십시오).

check 인자는 압축된 데이터에 포함할 무결성 검사 유형을 지정합니다. 이 검사는 압축을 풀 때 데이터가 손상되지 않았는지 확인하는 데 사용됩니다. 가능한 값은 다음과 같습니다:

CHECK_NONE: 무결성 검사가 없습니다. 이것은 FORMAT_ALONE과 FORMAT_RAW에 대한 기본값(그리고 유일하게 허용된 값)입니다.

CHECK_CRC32: 32비트 순환 중복 검사(Cyclic Redundancy Check).

CHECK_CRC64: 64비트 순환 중복 검사(Cyclic Redundancy Check). 이것이 FORMAT_XZ의 기본값입니다.

CHECK_SHA256: 256비트 보안 해시 알고리즘(Secure Hash Algorithm).

지정된 검사가 지원되지 않으면, LZMAError가 발생합니다.

압축 설정은 사전 설정 압축 수준(preset 인자 사용), 또는 사용자 정의 필터 체인(filters 인자 사용)으로 지정할 수 있습니다.

preset 인자(제공된 경우)는 0rhk 9 사이의 (경계 포함) 정수여야 하며, 선택적으로 상수 PRESET_EXTREME과 OR 할 수 있습니다. preset*과 *filters가 모두 제공되지 않으면, 기본 동작은 PRESET_DEFAULT(사전 설정 수준 6)를 사용하는 것입니다. 사전 설정이 높을수록 출력은 작아 지지만, 압축 과정은 느려집니다.

참고

CPU를 많이 사용하는 것 외에도, 사전 설정이 높은 압축은 훨씬 더 많은 메모리를 요구합니다 (그리고 압축을 풀기 위해 더 많은 메모리를 요구하는 출력을 생성합니다). 예를 들어 사전 설정 9를 사용하면, LZMACompressor 객체의 오버헤드가 800 MiB에 이를 수 있습니다. 이런 이유로, 일반적으로 기본 사전 설정을 사용하는 것이 가장 좋습니다.

filters 인자(제공된 경우)는 필터 체인 지정자여야 합니다. 자세한 내용은 사용자 정의 필터 체인 지정을 참조하십시오.

compress(data)

data(bytes 객체)를 압축하여, 적어도 입력의 일부에 대한 압축 데이터가 포함된 bytes 객체를 반환합니다. data의 일부는 나중에 compress()와 flush()에 대한 호출에 사용하기 위해 내부적으로 버퍼링 될 수 있습니다. 반환된 데이터는 compress()에 대한 이전 호출의 출력에 이어 붙여야 합니다.

flush()

압축 과정을 마치고, 압축기의 내부 버퍼에 저장된 모든 데이터가 포함된 bytes 객체를 반환합니다.

이 메서드를 호출한 후에는 압축기를 사용할 수 없습니다.

class lzma.LZMADecompressor(format=FORMAT_AUTO, memlimit=None, filters=None)

데이터를 점진적으로 압축 해제하는 데 사용할 수 있는 압축 해제기 객체를 만듭니다.

전체 압축 스트림을 한 번에 압축 해제하는 더 편리한 방법은 decompress()를 참조하십시오.

format 인자는 사용해야 하는 컨테이너 형식을 지정합니다. 기본값은 FORMAT_AUTO이며, .xz와 .lzma 파일을 모두 압축 해제할 수 있습니다. 다른 가능한 값은 FORMAT_XZ, FORMAT_ALONE 및 FORMAT_RAW입니다.

memlimit 인자는 압축 해제기가 사용할 수 있는 메모리양의 한계(바이트)를 지정합니다. 이 인자를 사용할 때, 주어진 메모리 한계 내에서 입력을 압축 해제할 수 없으면 LZMAError로 압축 해제에 실패합니다.

filters 인자는 압축 해제 중인 스트림을 만드는 데 사용된 필터 체인을 지정합니다. format이 FORMAT_RAW이면 이 인자가 필요하지만, 다른 형식에는 사용하지 않아야 합니다. 필터 체인에 대한 자세한 내용은 사용자 정의 필터 체인 지정을 참조하십시오.

참고

이 클래스는 decompress()와 LZMAFile과 달리, 여러 압축 스트림을 포함하는 입력을 투명하게 처리하지 않습니다. LZMADecompressor로 다중 스트림 입력을 압축 해제하려면 각 스트림에 대해 새로운 압축 해제기를 만들어야 합니다.

decompress(data, max_length=-1)

data(바이트열류 객체)를 압축 해제하고, 압축되지 않은 데이터를 바이트열로 반환합니다. data의 일부는 나중에 decompress()를 호출할 때 사용하기 위해 내부적으로 버퍼링 될 수 있습니다. 반환된 데이터는 decompress()에 대한 이전 호출의 출력에 이어 붙여야 합니다.

max_length가 음수가 아니면, 최대 max_length 바이트의 압축 해제된 데이터를 반환합니다. 이 한계에 도달하고 추가 출력을 생성할 수 있으면, needs_input 어트리뷰트가 False로 설정됩니다. 이 경우, 다음 decompress() 호출은 data를 b''로 제공하여 더 많은 출력을 얻을 수 있습니다.

모든 입력 데이터가 압축 해제되어 반환되면 (이것이 max_length 바이트 미만이거나 max_length가 음수이기 때문에), needs_input 어트리뷰트는 True로 설정됩니다.

Attempting to decompress data after the end of stream is reached raises an EOFError. Any data found after the end of the stream is ignored and saved in the unused_data attribute.

버전 3.5에서 변경: max_length 매개 변수를 추가했습니다.

check

입력 스트림이 사용하는 무결성 검사의 ID. 사용되는 무결성 검사를 결정하기 위해 충분한 입력이 디코딩될 때까지 CHECK_UNKNOWN일 수 있습니다.

eof

스트림 끝 마커에 도달하면 True.

unused_data

압축된 스트림이 끝난 후 발견된 데이터.

스트림의 끝에 도달하기 전에, 이것은 b""입니다.

needs_input

decompress() 메서드가 새로운 압축 입력을 요구하기 전에 더 많은 압축 해제된 데이터를 제공 할 수 있으면 False.

Added in version 3.5.

lzma.compress(data, format=FORMAT_XZ, check=-1, preset=None, filters=None)

data(bytes 객체)를 압축하여, 압축된 데이터를 bytes 객체로 반환합니다.

format, check, preset 및 filters 인자에 대한 설명은 위의 LZMACompressor를 참조하십시오.

lzma.decompress(data, format=FORMAT_AUTO, memlimit=None, filters=None)

data(bytes 객체)를 압축 해제하여, 압축되지 않은 데이터를 bytes 객체로 반환합니다.

data가 여러 개의 개별 압축 스트림의 연결이면, 이러한 스트림들을 모두 압축 해제하고 결과를 이어붙여 반환합니다.

format, memlimit 및 filters 인자에 대한 설명은 위의 LZMADecompressor를 참조하십시오.

기타

lzma.is_check_supported(check)

주어진 무결성 검사가 이 시스템에서 지원되면 True를 반환합니다.

CHECK_NONE과 CHECK_CRC32는 항상 지원됩니다. 제한된 기능 집합으로 컴파일된 liblzma 버전을 사용하는 경우 CHECK_CRC64와 CHECK_SHA256을 사용하지 못할 수 있습니다.

사용자 정의 필터 체인 지정

필터 체인 지정자는 딕셔너리의 시퀀스로, 각 딕셔너리에는 단일 필터의 ID와 옵션이 포함됩니다. 각 딕셔너리는 키 "id"를 포함해야 하며, 필터 종속 옵션을 지정하기 위해 추가 키를 포함할 수 있습니다. 유효한 필터 ID는 다음과 같습니다:

압축 필터:

FILTER_LZMA1 (FORMAT_ALONE과 함께 사용)

FILTER_LZMA2 (FORMAT_XZ 및 FORMAT_RAW와 함께 사용)

델타 필터:

FILTER_DELTA

Branch-Call-Jump (BCJ) 필터:

FILTER_X86

FILTER_IA64

FILTER_ARM

FILTER_ARMTHUMB

FILTER_POWERPC

FILTER_SPARC

필터 체인은 최대 4개의 필터로 구성될 수 있으며, 비워 둘 수 없습니다. 체인의 마지막 필터는 압축 필터여야 하고, 다른 필터는 델타나 BCJ 필터여야 합니다.

압축 필터는 다음 옵션을 지원합니다 (필터를 나타내는 딕셔너리에 추가 항목으로 지정됩니다):

preset: 명시적으로 지정되지 않은 옵션의 기본값 소스로 사용할 압축 사전 설정.

dict_size: 바이트로 표현한 딕셔너리 크기. 4 KiB와 1.5 GiB 사이여야 합니다 (경계 포함).

lc: 리터럴 컨텍스트 비트 수.

lp: 리터럴 위치 비트 수. 합계 lc + lp는 최대 4여야 합니다.

pb: 위치 비트 수; 최대 4여야 합니다.

mode: MODE_FAST나 MODE_NORMAL.

nice_len: 매치에서 “좋은 길이”로 간주하는 것. 273 이하여야 합니다.

mf: 사용할 매치 파인더 – MF_HC3, MF_HC4, MF_BT2, MF_BT3 또는 MF_BT4.

depth: 매치 파인더가 사용하는 최대 검색 깊이. 0(기본값)은 다른 필터 옵션을 기반으로 자동 선택함을 의미합니다.

델타 필터는 바이트 간 차이를 저장하여, 특정 상황에서 압축기에 대해 더 반복적인 입력을 생성합니다. 한 가지 옵션을 지원합니다, dist. 이것은 빼야 할 바이트 간의 거리를 나타냅니다. 기본값은 1입니다. 즉, 인접 바이트 간 차이를 취합니다.

BCJ 필터는 기계 코드에 적용하려는 것입니다. 이들은 압축기가 이용할 수 있는 중복성을 높이기 위해 코드에서 상대 분기, 호출 및 점프를 절대 주소 지정을 사용하도록 변환합니다. 이 필터는 한 가지 옵션을 지원합니다, start_offset. 이것은 입력 데이터의 시작 부분으로 매핑되어야 하는 주소를 지정합니다. 기본값은 0입니다.

예

압축 파일 읽기:

import lzma
with lzma.open("file.xz") as f:
    file_content = f.read()

압축 파일 만들기:

import lzma
data = b"Insert Data Here"
with lzma.open("file.xz", "w") as f:
    f.write(data)

메모리에서 데이터 압축하기:

import lzma
data_in = b"Insert Data Here"
data_out = lzma.compress(data_in)

증분 압축:

import lzma
lzc = lzma.LZMACompressor()
out1 = lzc.compress(b"Some data\n")
out2 = lzc.compress(b"Another piece of data\n")
out3 = lzc.compress(b"Even more data\n")
out4 = lzc.flush()
# Concatenate all the partial results:
result = b"".join([out1, out2, out3, out4])

이미 열린 파일에 압축된 데이터 쓰기:

import lzma
with open("file.xz", "wb") as f:
    f.write(b"This data will not be compressed\n")
    with lzma.open(f, "w") as lzf:
        lzf.write(b"This *will* be compressed\n")
    f.write(b"Not compressed\n")

사용자 정의 필터 체인을 사용하여 압축 파일 만들기:

import lzma
my_filters = [
    {"id": lzma.FILTER_DELTA, "dist": 5},
    {"id": lzma.FILTER_LZMA2, "preset": 7 | lzma.PRESET_EXTREME},
]
with lzma.open("file.xz", "w", filters=my_filters) as f:
    f.write(b"blah blah blah")

zipfile — Work with ZIP archives

Source code: Lib/zipfile/ [https://github.com/python/cpython/tree/main/Lib/zipfile/]

ZIP 파일 형식은 흔히 쓰이는 아카이브와 압축 표준입니다. 이 모듈은 ZIP 파일을 만들고, 읽고, 쓰고, 추가하고, 나열하는 도구를 제공합니다. 이 모듈의 고급 사용을 위해서는 PKZIP Application Note [https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT]에 정의된 형식의 이해가 필요합니다.

이 모듈은 현재 다중 디스크 ZIP 파일을 처리하지 않습니다. ZIP64 확장을 사용하는 ZIP 파일(즉, 크기가 4GiB 이상인 ZIP 파일)을 처리할 수 있습니다. ZIP 아카이브에 있는 암호화된 파일의 암호 해독을 지원하지만, 현재 암호화된 파일을 만들 수는 없습니다. C가 아닌 네이티브 파이썬으로 구현되므로 해독 속도가 매우 느립니다.

이 모듈은 다음 항목을 정의합니다:

exception zipfile.BadZipFile

잘못된 ZIP 파일로 인해 발생하는 에러.

Added in version 3.2.

exception zipfile.BadZipfile

이전 파이썬 버전과의 호환성을 위한, BadZipFile의 별칭.

버전 3.2부터 폐지됨.

exception zipfile.LargeZipFile

ZIP 파일에 ZIP64 기능이 필요하지만 활성화되지 않았을 때 발생하는 에러.

class zipfile.ZipFile

ZIP 파일을 읽고 쓰는 클래스. 생성자 세부 사항은 ZipFile 객체 섹션을 참조하십시오.

class zipfile.Path

Class that implements a subset of the interface provided by pathlib.Path, including the full importlib.resources.abc.Traversable interface.

Added in version 3.8.

class zipfile.PyZipFile

파이썬 라이브러리를 포함하는 ZIP 아카이브를 만들기 위한 클래스.

class zipfile.ZipInfo(filename='NoName', date_time=(1980, 1, 1, 0, 0, 0))

아카이브 멤버에 관한 정보를 나타내는 데 사용되는 클래스. 이 클래스의 인스턴스는 ZipFile 객체의 getinfo()와 infolist() 메서드에 의해 반환됩니다. zipfile 모듈의 대부분 사용자는 이것들을 만들 필요는 없고, 이 모듈에서 만든 것들을 사용하기만 합니다. filename은 아카이브 멤버의 전체 이름이어야 하고, date_time은 파일을 마지막으로 수정한 시간을 기술하는 6개의 필드를 포함하는 튜플이어야 합니다; 필드는 ZipInfo 객체 섹션에 설명되어 있습니다.

버전 3.13에서 변경: A public compress_level attribute has been added to expose the formerly protected _compresslevel. The older protected name continues to work as a property for backwards compatibility.

zipfile.is_zipfile(filename)

filename이 매직 번호에 기반하여 유효한 ZIP 파일이면 True를, 그렇지 않으면 False를 반환합니다. filename은 파일이거나 파일류 객체일 수도 있습니다.

버전 3.1에서 변경: 파일과 파일류 객체를 지원합니다.

zipfile.ZIP_STORED

압축되지 않은 아카이브 멤버를 위한 숫자 상수.

zipfile.ZIP_DEFLATED

일반적인 ZIP 압축 방법을 위한 숫자 상수. zlib 모듈이 필요합니다.

zipfile.ZIP_BZIP2

BZIP2 압축 방법을 위한 숫자 상수. bz2 모듈이 필요합니다.

Added in version 3.3.

zipfile.ZIP_LZMA

LZMA 압축 방법을 위한 숫자 상수. lzma 모듈이 필요합니다.

Added in version 3.3.

참고

ZIP 파일 형식 명세에는 2001년 이후 bzip2 압축, 2006년 이후 LZMA 압축 지원이 포함되어 있습니다. 그러나, 일부 도구(이전 파이썬 릴리스도 포함합니다)는 이러한 압축 방법을 지원하지 않으며, ZIP 파일 처리를 완전히 거부하거나, 개별 파일을 추출하는 데 실패합니다.

더 보기

PKZIP Application Note [https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT]

사용된 형식과 알고리즘의 저자인 Phil Katz의 ZIP 파일 형식에 대한 설명서.

Info-ZIP Home Page [https://infozip.sourceforge.net/]

Info-ZIP 프로젝트의 ZIP 아카이브 프로그램과 개발 라이브러리에 관한 정보.

ZipFile 객체

class zipfile.ZipFile(file, mode='r', compression=ZIP_STORED, allowZip64=True, compresslevel=None, *, strict_timestamps=True, metadata_encoding=None)

ZIP 파일을 엽니다, 여기서 file은 파일에 대한 경로 (문자열), 파일류 객체 또는 경로류 객체일 수 있습니다.

mode 매개 변수는 기존 파일을 읽으려면 'r', 새 파일을 자르고 쓰려면 'w', 기존 파일에 추가하려면 'a', 새 파일을 독점적으로 작성하고 쓰려면 'x' 이어야 합니다. mode가 'x'이고 file이 기존 파일을 참조하면, FileExistsError 가 발생합니다. mode가 'a'이고 file이 기존 ZIP 파일을 참조하면, 추가 파일이 이곳으로 추가됩니다. file이 ZIP 파일을 참조하지 않으면, 새 ZIP 아카이브를 파일에 덧붙입니다(append). 이는 ZIP 아카이브를 다른 파일(가령 python.exe)에 추가하기 위한 것입니다. mode가 'a'이고 파일이 아예 존재하지 않으면, 파일이 만들어집니다. mode가 'r'이나 'a'이면, 파일은 탐색 가능(seekable)해야 합니다.

compression은 아카이브를 기록할 때 사용할 ZIP 압축 방법이며, ZIP_STORED, ZIP_DEFLATED, ZIP_BZIP2 또는 ZIP_LZMA 이어야 합니다; 인식할 수 없는 값은 NotImplementedError 를 발생시킵니다. ZIP_DEFLATED, ZIP_BZIP2 또는 ZIP_LZMA가 지정되었지만, 해당 모듈(zlib, bz2 또는 lzma)을 사용할 수 없으면 RuntimeError가 발생합니다. 기본값은 ZIP_STORED입니다.

allowZip64가 True(기본값)이면 zipfile은 ZIP 파일이 4GiB보다 클 때 ZIP64 확장을 사용하는 ZIP 파일을 만듭니다. false이면 ZIP 파일에 ZIP64 확장자가 필요할 때 zipfile은 예외를 발생시킵니다.

compresslevel 매개 변수는 파일을 아카이브에 기록할 때 사용할 압축 수준을 제어합니다. ZIP_STORED나 ZIP_LZMA를 사용할 때는 효과가 없습니다. ZIP_DEFLATED를 사용할 때는 0에서 9까지의 정수가 허용됩니다 (자세한 내용은 zlib를 참조하십시오). ZIP_BZIP2를 사용할 때는 1부터 9까지의 정수가 허용됩니다 (자세한 내용은 bz2를 참조하십시오).

strict_timestamps 인자를 False로 설정하면, 1980-01-01 이전의 zip 파일을 허용하는 대신 타임 스탬프를 1980-01-01로 설정합니다. 2107-12-31 이후의 파일에 대해서도 비슷한 동작이 발생하며, 타임 스탬프는 역시 한곗값으로 설정됩니다.

When mode is 'r', metadata_encoding may be set to the name of a codec, which will be used to decode metadata such as the names of members and ZIP comments.

파일이 'w', 'x' 또는 'a' 모드로 만들어졌고 아카이브에 아무런 파일도 추가하지 않고 닫히면, 비어있는 아카이브에 적합한 ZIP 구조가 파일에 기록됩니다.

ZipFile은 또한 컨텍스트 관리자이므로 with 문을 지원합니다. 이 예에서, myzip은 with 문 스위트가 완료된 후에 닫힙니다 – 예외가 발생할 때조차 그렇습니다:

with ZipFile('spam.zip', 'w') as myzip:
    myzip.write('eggs.txt')

참고

metadata_encoding is an instance-wide setting for the ZipFile. It is not currently possible to set this on a per-member basis.

This attribute is a workaround for legacy implementations which produce archives with names in the current locale encoding or code page (mostly on Windows). According to the .ZIP standard, the encoding of metadata may be specified to be either IBM code page (default) or UTF-8 by a flag in the archive header. That flag takes precedence over metadata_encoding, which is a Python-specific extension.

버전 3.2에서 변경: ZipFile을 컨텍스트 관리자로 사용하는 기능이 추가되었습니다.

버전 3.3에서 변경: bzip2와 lzma 압축에 대한 지원이 추가되었습니다.

버전 3.4에서 변경: ZIP64 확장은 기본적으로 활성화됩니다.

버전 3.5에서 변경: 탐색할 수 없는(unseekable) 스트림으로의 쓰기 지원을 추가했습니다. 'x' 모드에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: 이전에는, 인식할 수 없는 compression 값에 대해 평범한 RuntimeError가 발생했습니다.

버전 3.6.2에서 변경: file 매개 변수는 경로류 객체를 받아들입니다.

버전 3.7에서 변경: compresslevel 매개 변수를 추가했습니다.

버전 3.8에서 변경: The strict_timestamps keyword-only parameter.

버전 3.11에서 변경: Added support for specifying member name encoding for reading metadata in the zipfile’s directory and file headers.

ZipFile.close()

아카이브 파일을 닫습니다. 프로그램을 종료하기 전에 close()를 호출해야 합니다. 그렇지 않으면 필수 레코드가 기록되지 않습니다.

ZipFile.getinfo(name)

아카이브 멤버 name에 관한 정보가 있는 ZipInfo 객체를 반환합니다. 현재 아카이브에 포함되지 않은 이름에 대해 getinfo()를 호출하면 KeyError가 발생합니다.

ZipFile.infolist()

아카이브의 각 멤버에 대한 ZipInfo 객체를 포함하는 리스트를 반환합니다. 기존 아카이브가 열린 경우 객체는 디스크의 실제 ZIP 파일에 있는 항목과 순서가 같습니다.

ZipFile.namelist()

아카이브 멤버의 리스트를 이름으로 반환합니다.

ZipFile.open(name, mode='r', pwd=None, *, force_zip64=False)

Access a member of the archive as a binary file-like object. name can be either the name of a file within the archive or a ZipInfo object. The mode parameter, if included, must be 'r' (the default) or 'w'. pwd is the password used to decrypt encrypted ZIP files as a bytes object.

open()은 컨텍스트 관리자이기도 하므로 with 문을 지원합니다:

with ZipFile('spam.zip') as myzip:
    with myzip.open('eggs.txt') as myfile:
        print(myfile.read())

With mode 'r' the file-like object (ZipExtFile) is read-only and provides the following methods: read(), readline(), readlines(), seek(), tell(), __iter__(), __next__(). These objects can operate independently of the ZipFile.

mode='w'에서, write() 메서드를 지원하는 쓰기 가능한 파일 핸들이 반환됩니다. 쓰기 가능한 파일 핸들이 열려있는 동안, ZIP 파일에서 다른 파일을 읽거나 쓰려고 시도하면 ValueError가 발생합니다.

In both cases the file-like object has also attributes name, which is equivalent to the name of a file within the archive, and mode, which is 'rb' or 'wb' depending on the input mode.

파일을 기록할 때, 파일 크기를 미리 알 수 없지만 2GiB를 초과할 수 있으면, 헤더 형식이 큰 파일을 지원할 수 있도록 force_zip64=True를 전달하십시오. 파일 크기가 미리 알려졌으면, file_size가 설정된 ZipInfo 객체를 구성하고, 이를 name 매개 변수로 사용하십시오.

참고

open(), read() 및 extract() 메서드는 파일명이나 ZipInfo 객체를 취할 수 있습니다. 중복 이름을 가진 멤버가 포함된 ZIP 파일을 읽으려고 할 때 이 점에 감사할 것입니다.

버전 3.6에서 변경: mode='U' 지원이 제거되었습니다. 유니버설 줄 넘김 모드로 압축된 텍스트 파일을 읽으려면 io.TextIOWrapper를 사용하십시오.

버전 3.6에서 변경: ZipFile.open() can now be used to write files into the archive with the mode='w' option.

버전 3.6에서 변경: 닫힌 ZipFile에 open()을 호출하면 ValueError가 발생합니다. 이전에는, RuntimeError가 발생했습니다.

버전 3.13에서 변경: Added attributes name and mode for the writeable file-like object. The value of the mode attribute for the readable file-like object was changed from 'r' to 'rb'.

ZipFile.extract(member, path=None, pwd=None)

Extract a member from the archive to the current working directory; member must be its full name or a ZipInfo object. Its file information is extracted as accurately as possible. path specifies a different directory to extract to. member can be a filename or a ZipInfo object. pwd is the password used for encrypted files as a bytes object.

만들어진 정규화된 경로(디렉터리나 새 파일)를 반환합니다.

참고

멤버 파일명이 절대 경로이면, 드라이브/UNC 공유 지점(sharepoint)과 선행 (역) 슬래시가 제거됩니다, 예를 들어: ///foo/bar는 유닉스에서 foo/bar가 되고, 윈도우에서 C:\foo\bar는 foo\bar가 됩니다. 그리고 멤버 파일명의 모든 ".." 구성 요소가 제거됩니다, 예를 들어: ../../foo../../ba..r은 foo../ba..r이 됩니다. 윈도우에서 잘못된 문자(:, <, >, |, ", ? 및 *)는 밑줄(_)로 대체됩니다.

버전 3.6에서 변경: 닫힌 ZipFile에서 extract()를 호출하면 ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

버전 3.6.2에서 변경: path 매개 변수는 경로류 객체를 받아들입니다.

ZipFile.extractall(path=None, members=None, pwd=None)

Extract all members from the archive to the current working directory. path specifies a different directory to extract to. members is optional and must be a subset of the list returned by namelist(). pwd is the password used for encrypted files as a bytes object.

경고

사전 검사 없이 신뢰할 수 없는 출처의 아카이브를 추출하지 마십시오. 파일이 path 밖에 만들어질 수 있습니다, 예를 들어 "/"로 시작하는 절대 파일명을 가진 멤버나 두 점 ".."을 포함하는 파일명. 이 모듈은 이를 방지하려고 시도합니다. extract() 참고를 참조하십시오.

버전 3.6에서 변경: 닫힌 ZipFile에서 extractall()을 호출하면 ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

버전 3.6.2에서 변경: path 매개 변수는 경로류 객체를 받아들입니다.

ZipFile.printdir()

아카이브의 목차를 sys.stdout으로 인쇄합니다.

ZipFile.setpassword(pwd)

Set pwd (a bytes object) as default password to extract encrypted files.

ZipFile.read(name, pwd=None)

Return the bytes of the file name in the archive. name is the name of the file in the archive, or a ZipInfo object. The archive must be open for read or append. pwd is the password used for encrypted files as a bytes object and, if specified, overrides the default password set with setpassword(). Calling read() on a ZipFile that uses a compression method other than ZIP_STORED, ZIP_DEFLATED, ZIP_BZIP2 or ZIP_LZMA will raise a NotImplementedError. An error will also be raised if the corresponding compression module is not available.

버전 3.6에서 변경: 닫힌 ZipFile에서 read()를 호출하면 ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

ZipFile.testzip()

아카이브의 모든 파일을 읽고 CRC와 파일 헤더를 확인합니다. 첫 번째 불량 파일의 이름을 반환하거나, None을 반환합니다.

버전 3.6에서 변경: 닫힌 ZipFile에서 testzip()을 호출하면 ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

ZipFile.write(filename, arcname=None, compress_type=None, compresslevel=None)

filename이라는 파일을 아카이브에 기록하고, 아카이브 이름으로 arcname을 지정합니다 (기본적으로, filename과 같지만, 드라이브 문자가 없고 선행 경로 구분 기호가 제거됩니다). 주어지면, compress_type은 새 항목에 대해 생성자의 compression 매개 변수에 제공된 값을 대체합니다. 마찬가지로, compresslevel은 주어지면 생성자를 대체합니다. 아카이브는 'w', 'x' 또는 'a' 모드로 열려 있어야 합니다.

참고

The ZIP file standard historically did not specify a metadata encoding, but strongly recommended CP437 (the original IBM PC encoding) for interoperability. Recent versions allow use of UTF-8 (only). In this module, UTF-8 will automatically be used to write the member names if they contain any non-ASCII characters. It is not possible to write member names in any encoding other than ASCII or UTF-8.

참고

아카이브 이름은 아카이브 루트에 상대적이어야 합니다. 즉, 경로 구분 기호로 시작해서는 안 됩니다.

참고

arcname(또는 arcname이 제공되지 않으면 filename)에 널 바이트가 포함되어 있으면, 아카이브의 파일 이름이 널 바이트에서 잘립니다.

참고

A leading slash in the filename may lead to the archive being impossible to open in some zip programs on Windows systems.

버전 3.6에서 변경: 'r' 모드로 만들어진 ZipFile이나 닫힌 ZipFile에서 write()를 호출하면 ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

ZipFile.writestr(zinfo_or_arcname, data, compress_type=None, compresslevel=None)

파일을 아카이브에 기록합니다. 내용은 data이며, str이나 bytes 인스턴스일 수 있습니다; str이면 먼저 UTF-8로 인코딩됩니다. zinfo_or_arcname은 아카이브에 제공될 파일 이름이거나 ZipInfo 인스턴스입니다. 인스턴스이면 최소한 파일명, 날짜 및 시간을 지정해야 합니다. 이름이면, 날짜와 시간이 현재 날짜와 시간으로 설정됩니다. 아카이브는 'w', 'x' 또는 'a' 모드로 열려 있어야 합니다.

주어지면, compress_type은 새 항목에 대해 생성자의 compression 매개 변수에 제공되거나 zinfo_or_arcname(ZipInfo 인스턴스인 경우)의 값을 대체합니다. 마찬가지로, compresslevel은 주어지면 생성자를 대체합니다.

참고

ZipInfo 인스턴스를 zinfo_or_arcname 매개 변수로 전달할 때, 사용되는 압축 방법은 주어진 ZipInfo 인스턴스의 compress_type 멤버에 지정된 압축 방법입니다. 기본적으로, ZipInfo 생성자는 이 멤버를 ZIP_STORED로 설정합니다.

버전 3.2에서 변경: compress_type 인자.

버전 3.6에서 변경: 'r' 모드로 만들어진 ZipFile이나 닫힌 ZipFile에서 writestr()을 호출하면, ValueError가 발생합니다. 이전에는 RuntimeError가 발생했습니다.

ZipFile.mkdir(zinfo_or_directory, mode=511)

Create a directory inside the archive. If zinfo_or_directory is a string, a directory is created inside the archive with the mode that is specified in the mode argument. If, however, zinfo_or_directory is a ZipInfo instance then the mode argument is ignored.

The archive must be opened with mode 'w', 'x' or 'a'.

Added in version 3.11.

다음과 같은 데이터 어트리뷰트도 사용할 수 있습니다:

ZipFile.filename

ZIP 파일의 이름.

ZipFile.debug

사용할 디버그 출력 수준. 이것은 0(기본값, 출력 없음)에서 3(가장 많은 출력)으로 설정될 수 있습니다. 디버깅 정보는 sys.stdout에 기록됩니다.

ZipFile.comment

ZIP 파일에 연관되는 주석은 bytes 객체입니다. 'w', 'x' 또는 'a' 모드로 만들어진 ZipFile 인스턴스에 주석을 대입하면, 65535바이트를 넘지 않아야 합니다. 이보다 긴 주석은 잘립니다.

Path 객체

class zipfile.Path(root, at='')

root zip 파일(ZipFile 생성자에 전달하기에 적합한 ZipFile 인스턴스나 file일 수 있습니다)에서 Path 객체를 생성합니다.

at은 zip 파일 내에서 이 Path의 위치를 지정합니다, 예를 들어 ‘dir/file.txt’, ‘dir/’ 또는 ‘’. 기본값은 빈 문자열이며, 루트를 나타냅니다.

Path 객체는 pathlib.Path 객체의 다음 기능을 노출합니다:

Path objects are traversable using the / operator or joinpath.

Path.name

최종 경로 구성 요소.

Path.open(mode='r', *, pwd, **)

현재 경로에서 ZipFile.open()을 호출합니다. 지원되는 모드를 통해 읽기 또는 쓰기, 텍스트 또는 바이너리로 여는 것을 허락합니다: ‘r’, ‘w’, ‘rb’, ‘wb’. 위치와 키워드 인자는 텍스트로 열 때 io.TextIOWrapper로 전달되고 그렇지 않으면 무시됩니다. pwd는 ZipFile.open()에 대한 pwd 매개 변수입니다.

버전 3.9에서 변경: open에 텍스트와 바이너리 모드에 대한 지원이 추가되었습니다. 기본 모드는 이제 텍스트입니다.

버전 3.11.2에서 변경: The encoding parameter can be supplied as a positional argument without causing a TypeError. As it could in 3.9. Code needing to be compatible with unpatched 3.10 and 3.11 versions must pass all io.TextIOWrapper arguments, encoding included, as keywords.

Path.iterdir()

현재 디렉터리의 자식을 열거합니다.

Path.is_dir()

현재 컨텍스트가 디렉터리를 참조하면 True를 반환합니다.

Path.is_file()

현재 컨텍스트가 파일을 참조하면 True를 반환합니다.

Path.is_symlink()

Return True if the current context references a symbolic link.

Added in version 3.12.

버전 3.13에서 변경: Previously, is_symlink would unconditionally return False.

Path.exists()

현재 컨텍스트가 zip 파일에 있는 파일이나 디렉터리를 참조하면 True를 반환합니다.

Path.suffix

The last dot-separated portion of the final component, if any. This is commonly called the file extension.

Added in version 3.11: Added Path.suffix property.

Path.stem

The final path component, without its suffix.

Added in version 3.11: Added Path.stem property.

Path.suffixes

A list of the path’s suffixes, commonly called file extensions.

Added in version 3.11: Added Path.suffixes property.

Path.read_text(*, **)

현재 파일을 유니코드 텍스트로 읽습니다. 위치와 키워드 인자는 io.TextIOWrapper로 전달됩니다 (컨텍스트에 의해 암시되는 buffer 제외).

버전 3.11.2에서 변경: The encoding parameter can be supplied as a positional argument without causing a TypeError. As it could in 3.9. Code needing to be compatible with unpatched 3.10 and 3.11 versions must pass all io.TextIOWrapper arguments, encoding included, as keywords.

Path.read_bytes()

현재 파일을 바이트열로 읽습니다.

Path.joinpath(*other)

Return a new Path object with each of the other arguments joined. The following are equivalent:

>>> Path(...).joinpath('child').joinpath('grandchild')
>>> Path(...).joinpath('child', 'grandchild')
>>> Path(...) / 'child' / 'grandchild'

버전 3.10에서 변경: Prior to 3.10, joinpath was undocumented and accepted exactly one parameter.

The zipp [https://pypi.org/project/zipp/] project provides backports of the latest path object functionality to older Pythons. Use zipp.Path in place of zipfile.Path for early access to changes.

PyZipFile 객체

PyZipFile 생성자는 ZipFile 생성자와 같은 매개 변수와 하나의 추가 매개 변수 optimize를 취합니다.

class zipfile.PyZipFile(file, mode='r', compression=ZIP_STORED, allowZip64=True, optimize=-1)

버전 3.2에서 변경: Added the optimize parameter.

버전 3.4에서 변경: ZIP64 확장은 기본적으로 활성화됩니다.

인스턴스에는 ZipFile 객체의 메서드들 외에 한 가지 추가 메서드가 있습니다:

writepy(pathname, basename='', filterfunc=None)

파일 *.py를 검색하고 해당 파일을 아카이브에 추가합니다.

PyZipFile에 대한 optimize 매개 변수가 제공되지 않았거나 -1이면, 해당 파일은 *.pyc 파일이며, 필요하면 컴파일합니다.

PyZipFile에 대한 optimize 매개 변수가 0, 1 또는 2이면, 해당 최적화 수준(compile()을 참조하십시오)의 파일 만 아카이브에 추가되며, 필요하면 컴파일합니다.

pathname이 파일이면, 파일 이름은 .py로 끝나야하며, 단지 그 (해당 *.pyc) 파일 만 최상위 수준에 추가됩니다 (경로 정보 없음). pathname이 .py로 끝나지 않는 파일이면, RuntimeError가 발생합니다. 디렉터리이고, 디렉터리가 패키지 디렉터리가 아니면, 모든 파일 *.pyc가 최상위 수준에 추가됩니다. 디렉터리가 패키지 디렉터리이면, 모든 *.pyc가 패키지 이름의 파일 경로 아래에 추가되고, 서브 디렉터리가 패키지 디렉터리이면, 이들 모두도 재귀적으로 정렬된 순서로 추가됩니다.

basename은 내부 전용입니다.

filterfunc가 주어지면, 단일 문자열 인자를 취하는 함수여야 합니다. 아카이브에 추가되기 전에 각 경로(개별 전체 파일 경로를 포함합니다)를 전달합니다. filterfunc가 거짓 값을 반환하면, 경로가 추가되지 않으며, 디렉터리이면 내용이 무시됩니다. 예를 들어, 테스트 파일이 모두 test 디렉터리에 있거나 문자열 test_로 시작하면, filterfunc를 사용하여 해당 파일들을 제외할 수 있습니다:

>>> zf = PyZipFile('myprog.zip')
>>> def notests(s):
...     fn = os.path.basename(s)
...     return (not (fn == 'test' or fn.startswith('test_')))
...
>>> zf.writepy('myprog', filterfunc=notests)

writepy() 메서드는 다음과 같은 파일 이름으로 아카이브를 만듭니다:

string.pyc                   # Top level name
test/__init__.pyc            # Package directory
test/testall.pyc             # Module test.testall
test/bogus/__init__.pyc      # Subpackage directory
test/bogus/myfile.pyc        # Submodule test.bogus.myfile

버전 3.4에서 변경: Added the filterfunc parameter.

버전 3.6.2에서 변경: pathname 매개 변수는 경로류 객체를 받아들입니다.

버전 3.7에서 변경: 재귀는 디렉터리 항목을 정렬합니다.

ZipInfo 객체

ZipInfo 클래스의 인스턴스는 ZipFile 객체의 getinfo()와 infolist() 메서드가 반환합니다. 각 객체는 ZIP 아카이브의 단일 멤버에 대한 정보를 저장합니다.

파일 시스템 파일의 ZipInfo 인스턴스를 만드는 클래스 메서드가 하나 있습니다:

classmethod ZipInfo.from_file(filename, arcname=None, *, strict_timestamps=True)

zip 파일에 파일을 추가할 수 있도록, 파일 시스템의 파일에 대한 ZipInfo 인스턴스를 생성합니다.

filename은 파일 시스템에서 파일이나 디렉터리의 경로여야 합니다.

arcname이 지정되면, 아카이브 내에서의 이름으로 사용됩니다. arcname을 지정하지 않으면, 이름은 filename과 같지만, 드라이브 문자와 선행 경로 구분 기호가 제거됩니다.

strict_timestamps 인자를 False로 설정하면, 1980-01-01 이전의 zip 파일을 허용하는 대신 타임 스탬프를 1980-01-01로 설정합니다. 2107-12-31 이후의 파일에 대해서도 비슷한 동작이 발생하며, 타임 스탬프는 역시 한곗값으로 설정됩니다.

Added in version 3.6.

버전 3.6.2에서 변경: filename 매개 변수는 경로류 객체를 받아들입니다.

버전 3.8에서 변경: Added the strict_timestamps keyword-only parameter.

인스턴스에는 다음과 같은 메서드와 어트리뷰트가 있습니다:

ZipInfo.is_dir()

이 아카이브 멤버가 디렉터리이면 True를 반환합니다.

이것은 항목 이름을 사용합니다: 디렉터리는 항상 /로 끝나야 합니다.

Added in version 3.6.

ZipInfo.filename

아카이브에서의 파일의 이름.

ZipInfo.date_time

아카이브 멤버를 마지막으로 수정한 시간과 날짜. 이것은 6개의 값으로 구성된 튜플입니다:

인덱스

값

0

연도 (>= 1980)

1

월 (1에서 시작)

2

월 중 일 (1에서 시작)

3

시간 (0에서 시작)

4

분 (0에서 시작)

5

초 (0에서 시작)

참고

ZIP 파일 형식은 1980년 이전의 타임 스탬프를 지원하지 않습니다.

ZipInfo.compress_type

아카이브 멤버의 압축 유형.

ZipInfo.comment

bytes 객체로 제공되는 개별 아카이브 멤버에 대한 주석.

ZipInfo.extra

확장 필드 데이터. PKZIP Application Note [https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT]는 이 bytes 객체에 포함된 데이터의 내부 구조에 대한 주석을 포함합니다.

ZipInfo.create_system

ZIP 아카이브를 만든 시스템.

ZipInfo.create_version

ZIP 아카이브를 만든 PKZIP 버전.

ZipInfo.extract_version

아카이브를 추출하기 위해 필요한 PKZIP 버전.

ZipInfo.reserved

반드시 0이어야 합니다.

ZipInfo.flag_bits

ZIP 플래그 비트.

ZipInfo.volume

파일 헤더의 볼륨 번호.

ZipInfo.internal_attr

내부 어트리뷰트.

ZipInfo.external_attr

외부 파일 어트리뷰트.

ZipInfo.header_offset

파일 헤더의 바이트 오프셋.

ZipInfo.CRC

압축되지 않은 파일의 CRC-32.

ZipInfo.compress_size

압축된 데이터의 크기.

ZipInfo.file_size

압축되지 않은 파일의 크기.

명령 줄 인터페이스

zipfile 모듈은 ZIP 아카이브와 상호 작용하기 위한 간단한 명령 줄 인터페이스를 제공합니다.

새 ZIP 아카이브를 만들려면 -c 옵션 뒤에 이름을 지정한 다음 포함해야 할 파일 이름을 나열하십시오:

$ python -m zipfile -c monty.zip spam.txt eggs.txt

디렉터리 전달도 허용됩니다:

$ python -m zipfile -c monty.zip life-of-brian_1979/

ZIP 아카이브를 지정된 디렉터리로 추출하려면, -e 옵션을 사용하십시오:

$ python -m zipfile -e monty.zip target-dir/

ZIP 아카이브에 있는 파일 목록을 보려면, -l 옵션을 사용하십시오:

$ python -m zipfile -l monty.zip

명령 줄 옵션

-l <zipfile>

--list <zipfile>

zip 파일에 있는 파일을 나열합니다.

-c <zipfile> <source1> ... <sourceN>

--create <zipfile> <source1> ... <sourceN>

소스 파일로 zip 파일을 만듭니다.

-e <zipfile> <output_dir>

--extract <zipfile> <output_dir>

zip 파일을 대상 디렉터리로 추출합니다.

-t <zipfile>

--test <zipfile>

zip 파일이 유효한지 테스트합니다.

--metadata-encoding <encoding>

Specify encoding of member names for -l, -e and -t.

Added in version 3.11.

압축 해제 함정

아래 나열된 일부 함정으로 인해 zipfile 모듈에서의 추출이 실패할 수 있습니다.

파일 자체에서

잘못된 암호 / CRC 체크섬 / ZIP 형식 또는 지원되지 않는 압축 방법 / 암호 해독으로 인해 압축 해제에 실패할 수 있습니다.

파일 시스템 제한

다른 파일 시스템의 제한을 초과하면 압축 해제에 실패할 수 있습니다. 가령 디렉터리 항목에 허용되는 문자, 파일 이름 길이, 경로명 길이, 단일 파일 크기 및 파일 수 등.

자원 제한

메모리나 디스크 볼륨이 부족하면 압축 해제에 실패합니다. 예를 들어, 압축 해제 폭탄(일명 ZIP bomb [https://en.wikipedia.org/wiki/Zip_bomb])을 zipfile 라이브러리에 적용하면 디스크 볼륨이 소진될 수 있습니다.

중단

Ctrl-C 누르기나 압축 해제 프로세스를 죽이는 것과 같은 압축 해제 중 중단으로 인해 아카이브 압축 해제가 불완전할 수 있습니다.

추출의 기본 동작

기본 추출 동작을 모르면 예기치 않은 압축 해제 결과가 발생할 수 있습니다. 예를 들어, 같은 아카이브를 두 번 추출하면, 묻지 않고 파일을 덮어씁니다.

tarfile — Read and write tar archive files

소스 코드: Lib/tarfile.py [https://github.com/python/cpython/tree/main/Lib/tarfile.py]

tarfile 모듈을 사용하면 gzip, bz2 및 lzma 압축을 사용하는 것을 포함하여, tar 아카이브를 읽고 쓸 수 있습니다. .zip 파일을 읽거나 쓰려면 zipfile 모듈이나 shutil에 있는 고수준 함수를 사용하십시오.

몇 가지 세부 사항:

해당 모듈을 사용할 수 있으면 gzip, bz2 및 lzma 압축 아카이브를 읽고 씁니다.

POSIX.1-1988 (ustar) 형식에 대한 읽기/쓰기 지원.

longname과 longlink 확장을 포함한 GNU tar 형식에 대한 읽기/쓰기 지원, 스파스(sparse) 파일 복원을 포함하여 모든 sparse 확장 변형에 대한 읽기 전용 지원.

POSIX.1-2001 (pax) 형식에 대한 읽기/쓰기 지원.

디렉터리, 일반 파일, 하드 링크, 심볼릭 링크, fifo, 문자 장치 및 블록 장치를 처리하고 타임 스탬프, 액세스 권한 및 소유자와 같은 파일 정보를 획득하고 복원할 수 있습니다.

버전 3.3에서 변경: lzma 압축에 대한 지원이 추가되었습니다.

버전 3.12에서 변경: Archives are extracted using a filter, which makes it possible to either limit surprising/dangerous features, or to acknowledge that they are expected and the archive is fully trusted.

버전 3.14에서 변경: Set the default extraction filter to data, which disallows some dangerous features such as links to absolute paths or paths outside of the destination. Previously, the filter strategy was equivalent to fully_trusted.

tarfile.open(name=None, mode='r', fileobj=None, bufsize=10240, **kwargs)

경로명 name에 대한 TarFile 객체를 반환합니다. TarFile 객체와 허용되는 키워드 인자에 대한 자세한 정보는 TarFile 객체를 참조하십시오.

mode는 'filemode[:compression]' 형식의 문자열이어야 하며, 기본값은 'r'입니다. 다음은 mode 조합의 전체 목록입니다:

모드

동작

'r' 또는 'r:*'

투명한 압축으로 읽기 위해 엽니다 (권장합니다).

'r:'

압축하지 않고 독점적으로 읽기 위해 엽니다.

'r:gz'

gzip 압축으로 읽기 위해 엽니다.

'r:bz2'

bzip2 압축으로 읽기 위해 엽니다.

'r:xz'

lzma 압축으로 읽기 위해 엽니다.

'x' 또는 'x:'

Create a tarfile exclusively without compression. Raise a FileExistsError exception if it already exists.

'x:gz'

Create a tarfile with gzip compression. Raise a FileExistsError exception if it already exists.

'x:bz2'

Create a tarfile with bzip2 compression. Raise a FileExistsError exception if it already exists.

'x:xz'

Create a tarfile with lzma compression. Raise a FileExistsError exception if it already exists.

'a' 또는 'a:'

압축하지 않고 추가하기 위해 엽니다. 파일이 없으면 만들어집니다.

'w' 또는 'w:'

압축되지 않은 쓰기를 위해 엽니다.

'w:gz'

gzip 압축 쓰기를 위해 엽니다.

'w:bz2'

bzip2 압축 쓰기를 위해 엽니다.

'w:xz'

lzma 압축 쓰기를 위해 엽니다.

'a:gz', 'a:bz2' 또는 'a:xz'는 불가능함에 유의하십시오. mode가 특정 (압축된) 파일을 읽기 위해 여는 데 적합하지 않으면 ReadError가 발생합니다. 이것을 피하려면 mode 'r'을 사용하십시오. 압축 방법이 지원되지 않으면, CompressionError가 발생합니다.

fileobj가 지정되면, name에 대해 바이너리 모드로 열린 파일 객체의 대안으로 사용됩니다. 위치 0에 있다고 가정합니다.

For modes 'w:gz', 'x:gz', 'w|gz', 'w:bz2', 'x:bz2', 'w|bz2', tarfile.open() accepts the keyword argument compresslevel (default 9) to specify the compression level of the file.

For modes 'w:xz' and 'x:xz', tarfile.open() accepts the keyword argument preset to specify the compression level of the file.

For special purposes, there is a second format for mode: 'filemode|[compression]'. tarfile.open() will return a TarFile object that processes its data as a stream of blocks. No random seeking will be done on the file. If given, fileobj may be any object that has a read() or write() method (depending on the mode) that works with bytes. bufsize specifies the blocksize and defaults to 20 * 512 bytes. Use this variant in combination with e.g. sys.stdin.buffer, a socket file object or a tape device. However, such a TarFile object is limited in that it does not allow random access, see 예. The currently possible modes:

모드

동작

'r|*'

투명한 압축으로 읽기 위해 tar 블록의 스트림을 엽니다.

'r|'

읽기 위해 압축되지 않은 tar 블록의 스트림을 엽니다.

'r|gz'

읽기 위해 gzip 압축 스트림을 엽니다.

'r|bz2'

읽기 위해 bzip2 압축 스트림을 엽니다.

'r|xz'

읽기 위해 lzma 압축 스트림을 엽니다.

'w|'

쓰기 위해 압축되지 않은 스트림을 엽니다.

'w|gz'

쓰기 위해 gzip 압축 스트림을 엽니다.

'w|bz2'

쓰기 위해 bzip2 압축 스트림을 엽니다.

'w|xz'

쓰기 위해 lzma 압축 스트림을 엽니다.

버전 3.5에서 변경: 'x' (독점 생성) 모드가 추가되었습니다.

버전 3.6에서 변경: name 매개 변수는 경로류 객체를 받아들입니다.

버전 3.12에서 변경: The compresslevel keyword argument also works for streams.

class tarfile.TarFile

tar 아카이브를 읽고 쓰는 클래스. 이 클래스를 직접 사용하지 마십시오: 대신 tarfile.open()을 사용하십시오. TarFile 객체를 참조하십시오.

tarfile.is_tarfile(name)

name이 tarfile 모듈이 읽을 수 있는 tar 아카이브 파일이면 True를 반환합니다. name은 str, 파일 또는 파일류 객체일 수 있습니다.

버전 3.9에서 변경: 파일과 파일류 객체 지원.

tarfile 모듈은 다음 예외를 정의합니다:

exception tarfile.TarError

모든 tarfile 예외의 베이스 클래스.

exception tarfile.ReadError

tarfile 모듈에서 처리할 수 없거나 어떤 식으로든 유효하지 않은 tar 아카이브가 열릴 때 발생합니다.

exception tarfile.CompressionError

압축 방법이 지원되지 않거나 데이터를 올바르게 디코딩할 수 없을 때 발생합니다.

exception tarfile.StreamError

스트림류 TarFile 객체에 일반적인 제한 사항으로 인해 발생합니다.

exception tarfile.ExtractError

TarFile.extract()를 사용할 때 치명적이지 않은 에러에 대해 발생하지만, TarFile.errorlevel== 2일 때만 발생합니다.

exception tarfile.HeaderError

버퍼가 유효하지 않을 때 TarInfo.frombuf()에 의해 발생합니다.

exception tarfile.FilterError

Base class for members refused by filters.

tarinfo

Information about the member that the filter refused to extract, as TarInfo.

exception tarfile.AbsolutePathError

Raised to refuse extracting a member with an absolute path.

exception tarfile.OutsideDestinationError

Raised to refuse extracting a member outside the destination directory.

exception tarfile.SpecialFileError

Raised to refuse extracting a special file (e.g. a device or pipe).

exception tarfile.AbsoluteLinkError

Raised to refuse extracting a symbolic link with an absolute path.

exception tarfile.LinkOutsideDestinationError

Raised to refuse extracting a symbolic link pointing outside the destination directory.

모듈 수준에서 다음 상수를 사용할 수 있습니다:

tarfile.ENCODING

기본 문자 인코딩: 윈도우의 경우 'utf-8', 그렇지 않으면 sys.getfilesystemencoding() 이 반환하는 값.

tarfile.REGTYPE

tarfile.AREGTYPE

A regular file type.

tarfile.LNKTYPE

A link (inside tarfile) type.

tarfile.SYMTYPE

A symbolic link type.

tarfile.CHRTYPE

A character special device type.

tarfile.BLKTYPE

A block special device type.

tarfile.DIRTYPE

A directory type.

tarfile.FIFOTYPE

A FIFO special device type.

tarfile.CONTTYPE

A contiguous file type.

tarfile.GNUTYPE_LONGNAME

A GNU tar longname type.

tarfile.GNUTYPE_LONGLINK

A GNU tar longlink type.

tarfile.GNUTYPE_SPARSE

A GNU tar sparse file type.

다음의 각 상수는 tarfile 모듈이 만들 수 있는 tar 아카이브 형식을 정의합니다. 자세한 내용은 지원되는 tar 형식 섹션을 참조하십시오.

tarfile.USTAR_FORMAT

POSIX.1-1988 (ustar) 형식.

tarfile.GNU_FORMAT

GNU tar 형식.

tarfile.PAX_FORMAT

POSIX.1-2001 (pax) 형식.

tarfile.DEFAULT_FORMAT

아카이브를 만들기 위한 기본 형식. 이것은 현재 PAX_FORMAT입니다.

버전 3.8에서 변경: 새 아카이브의 기본 형식이 GNU_FORMAT에서 PAX_FORMAT으로 변경되었습니다.

더 보기

모듈 zipfile

zipfile 표준 모듈의 설명서.

아카이브 연산

표준 shutil 모듈이 제공하는 고수준 아카이브 기능에 대한 설명서.

GNU tar manual, Basic Tar Format [https://www.gnu.org/software/tar/manual/html_node/Standard.html]

GNU tar 확장을 포함한, tar 아카이브 파일에 대한 설명서.

TarFile 객체

TarFile 객체는 tar 아카이브에 대한 인터페이스를 제공합니다. tar 아카이브는 블록의 시퀀스입니다. 아카이브 멤버(저장된 파일)는 헤더 블록과 그 뒤에 오는 데이터 블록으로 구성됩니다. tar 아카이브에 파일을 여러 번 저장할 수 있습니다. 각 아카이브 멤버는 TarInfo 객체로 표현됩니다. 세부 사항은 TarInfo 객체를 참조하십시오.

TarFile 객체는 with 문에서 컨텍스트 관리자로 사용될 수 있습니다. 블록이 완료되면 자동으로 닫힙니다. 예외가 있는 경우, 쓰기 위해 열린 아카이브는 마무리되지 않음에 유의하십시오; 내부적으로 사용된 파일 객체만 닫힙니다. 사용 사례는 예 섹션을 참조하십시오.

Added in version 3.2: 컨텍스트 관리 프로토콜에 대한 지원이 추가되었습니다.

class tarfile.TarFile(name=None, mode='r', fileobj=None, format=DEFAULT_FORMAT, tarinfo=TarInfo, dereference=False, ignore_zeros=False, encoding=ENCODING, errors='surrogateescape', pax_headers=None, debug=0, errorlevel=1, stream=False)

다음의 모든 인자는 선택적이며 인스턴스 어트리뷰트로도 액세스 할 수 있습니다.

name is the pathname of the archive. name may be a path-like object. It can be omitted if fileobj is given. In this case, the file object’s name attribute is used if it exists.

mode는 기존 아카이브에서 읽는 'r', 기존 파일에 데이터를 추가하는 'a', 기존 파일을 덮어쓰는 새 파일을 만드는 'w' 또는 존재하지 않을 때만 새 파일을 만드는 'x'입니다.

fileobj가 주어지면, 데이터를 읽거나 쓰는 데 사용됩니다. 그것이 결정될 수 있다면, mode는 fileobj의 모드에 의해 재정의됩니다. fileobj는 위치 0에서 사용됩니다.

참고

TarFile이 닫힐 때, fileobj는 닫히지 않습니다.

format은 쓰기를 위한 아카이브 형식을 제어합니다. 모듈 수준에서 정의되는 상수 USTAR_FORMAT, GNU_FORMAT 또는 PAX_FORMAT 중 하나여야 합니다. 읽을 때, 형식은 자동 감지됩니다, 단일 아카이브에 다른 형식이 존재할 때조차 그렇습니다.

tarinfo 인자를 사용하여 기본 TarInfo 클래스를 다른 클래스로 바꿀 수 있습니다.

dereference가 False이면, 아카이브에 심볼릭과 하드 링크를 추가합니다. True이면, 대상 파일의 내용을 아카이브에 추가합니다. 이는 심볼릭 링크를 지원하지 않는 시스템에는 영향을 미치지 않습니다.

ignore_zeros가 False이면, 빈 블록을 아카이브의 끝으로 처리합니다. True이면, 비어있는 (그래서 잘못된) 블록을 건너뛰고 최대한 많은 멤버를 확보하려고 합니다. 이어붙였거나 손상된 아카이브를 읽을 때만 유용합니다.

debug는 0(디버그 메시지 없음)에서 3(모든 디버그 메시지)까지 설정할 수 있습니다. 메시지는 sys.stderr에 기록됩니다.

errorlevel controls how extraction errors are handled, see the corresponding attribute.

encoding과 errors 인자는 아카이브를 읽거나 쓰는 데 사용되는 문자 인코딩과 변환 에러 처리 방법을 정의합니다. 기본 설정은 대부분의 사용자에게 적용됩니다. 자세한 정보는 유니코드 문제 섹션을 참조하십시오.

pax_headers 인자는 선택적인 문자열의 딕셔너리로, format이 PAX_FORMAT이면 pax 전역 헤더로 추가됩니다.

If stream is set to True then while reading the archive info about files in the archive are not cached, saving memory.

버전 3.2에서 변경: errors 인자의 기본값으로 'surrogateescape'를 사용합니다.

버전 3.5에서 변경: 'x' (독점 생성) 모드가 추가되었습니다.

버전 3.6에서 변경: name 매개 변수는 경로류 객체를 받아들입니다.

버전 3.13에서 변경: Add the stream parameter.

classmethod TarFile.open(...)

대체 생성자. tarfile.open() 함수는 실제로 이 클래스 메서드의 바로 가기입니다.

TarFile.getmember(name)

멤버 name에 대한 TarInfo 객체를 반환합니다. 아카이브에서 name을 찾을 수 없으면 KeyError가 발생합니다.

참고

아카이브에서 멤버가 두 번 이상 등장하면, 마지막 등장을 최신 버전으로 간주합니다.

TarFile.getmembers()

아카이브 멤버를 TarInfo 객체의 리스트로 반환합니다. 리스트는 아카이브의 멤버와 순서가 같습니다.

TarFile.getnames()

멤버를 이름의 리스트로 반환합니다. getmembers()가 반환하는 리스트와 순서가 같습니다.

TarFile.list(verbose=True, *, members=None)

목차를 sys.stdout으로 인쇄합니다. verbose가 False이면, 멤버 이름만 인쇄됩니다. True이면, ls -l과 유사한 출력이 생성됩니다. 선택적 members가 제공되면, getmembers()가 반환한 리스트의 부분집합이어야 합니다.

버전 3.5에서 변경: members 매개 변수를 추가했습니다.

TarFile.next()

TarFile을 읽기 위해 열었을 때, 아카이브의 다음 멤버를 TarInfo 객체로 반환합니다. 더는 없으면, None을 반환합니다.

TarFile.extractall(path='.', members=None, *, numeric_owner=False, filter=None)

아카이브의 모든 멤버(members)를 현재 작업 디렉터리나 디렉터리 path로 추출합니다. 선택적 members가 제공되면, getmembers()가 반환하는 리스트의 부분집합이어야 합니다. 소유자, 수정 시간 및 권한과 같은 디렉터리 정보는 모든 멤버가 추출된 후에 설정됩니다. 이것은 두 가지 문제를 해결하기 위한 것입니다: 디렉터리의 수정 시간은 파일이 생성될 때마다 재설정됩니다. 또한 디렉터리의 권한이 쓰기를 허용하지 않으면, 파일 추출이 실패합니다.

numeric_owner가 True이면, tar 파일의 uid와 gid 번호는 추출된 파일의 소유자/그룹을 설정하는 데 사용됩니다. 그렇지 않으면, tar 파일의 이름값이 사용됩니다.

The filter argument specifies how members are modified or rejected before extraction. See Extraction filters for details. It is recommended to set this explicitly only if specific tar features are required, or as filter='data' to support Python versions with a less secure default (3.13 and lower).

경고

Never extract archives from untrusted sources without prior inspection.

Since Python 3.14, the default (data) will prevent the most dangerous security issues. However, it will not prevent all unintended or insecure behavior. Read the Extraction filters section for details.

버전 3.5에서 변경: numeric_owner 매개 변수를 추가했습니다.

버전 3.6에서 변경: path 매개 변수는 경로류 객체를 받아들입니다.

버전 3.12에서 변경: filter 매개 변수를 추가했습니다.

버전 3.14에서 변경: The filter parameter now defaults to 'data'.

TarFile.extract(member, path='', set_attrs=True, *, numeric_owner=False, filter=None)

전체 이름을 사용하여, 아카이브에서 현재 작업 디렉터리로 멤버(member)를 추출합니다. 파일 정보는 최대한 정확하게 추출됩니다. member는 파일명이나 TarInfo 객체일 수 있습니다. path를 사용하여 다른 디렉터리를 지정할 수 있습니다. path는 경로류 객체일 수 있습니다. set_attrs가 거짓이 아닌 한 파일 어트리뷰트(소유자, 수정 시간, 모드)가 설정됩니다.

The numeric_owner and filter arguments are the same as for extractall().

참고

extract() 메서드는 여러 추출 문제를 처리하지 않습니다. 대부분의 경우 extractall() 메서드 사용을 고려해야 합니다.

경고

Never extract archives from untrusted sources without prior inspection. See the warning for extractall() for details.

버전 3.2에서 변경: set_attrs 매개 변수를 추가했습니다.

버전 3.5에서 변경: numeric_owner 매개 변수를 추가했습니다.

버전 3.6에서 변경: path 매개 변수는 경로류 객체를 받아들입니다.

버전 3.12에서 변경: filter 매개 변수를 추가했습니다.

TarFile.extractfile(member)

아카이브에서 멤버(member)를 파일 객체로 추출합니다. member는 파일명이나 TarInfo 객체일 수 있습니다. member가 일반 파일이나 링크이면, io.BufferedReader 객체가 반환됩니다. 다른 모든 기존 멤버에 대해서는, None이 반환됩니다. member가 아카이브에 없으면, KeyError가 발생합니다.

버전 3.3에서 변경: io.BufferedReader 객체를 반환합니다.

버전 3.13에서 변경: The returned io.BufferedReader object has the mode attribute which is always equal to 'rb'.

TarFile.errorlevel: int

If errorlevel is 0, errors are ignored when using TarFile.extract() and TarFile.extractall(). Nevertheless, they appear as error messages in the debug output when debug is greater than 0. If 1 (the default), all fatal errors are raised as OSError or FilterError exceptions. If 2, all non-fatal errors are raised as TarError exceptions as well.

Some exceptions, e.g. ones caused by wrong argument types or data corruption, are always raised.

Custom extraction filters should raise FilterError for fatal errors and ExtractError for non-fatal ones.

Note that when an exception is raised, the archive may be partially extracted. It is the user’s responsibility to clean up.

TarFile.extraction_filter

Added in version 3.12.

The extraction filter used as a default for the filter argument of extract() and extractall().

The attribute may be None or a callable. String names are not allowed for this attribute, unlike the filter argument to extract().

If extraction_filter is None (the default), extraction methods will use the data filter by default.

The attribute may be set on instances or overridden in subclasses. It also is possible to set it on the TarFile class itself to set a global default, although, since it affects all uses of tarfile, it is best practice to only do so in top-level applications or site configuration. To set a global default this way, a filter function needs to be wrapped in staticmethod() to prevent injection of a self argument.

버전 3.14에서 변경: The default filter is set to data, which disallows some dangerous features such as links to absolute paths or paths outside of the destination. Previously, the default was equivalent to fully_trusted.

TarFile.add(name, arcname=None, recursive=True, *, filter=None)

name 파일을 아카이브에 추가합니다. name은 모든 유형의 파일(디렉터리, fifo, 심볼릭 링크 등)일 수 있습니다. 지정되면, arcname은 아카이브에 있는 파일의 대체 이름을 지정합니다. 디렉터리는 기본적으로 재귀적으로 추가됩니다. recursive를 False로 설정하면, 이를 피할 수 있습니다. 재귀는 항목을 정렬된 순서로 추가합니다. filter가 제공되면, TarInfo 객체 인자를 취하고 변경된 TarInfo 객체를 반환하는 함수여야 합니다. 이것이 대신 None을 반환하면, TarInfo 객체가 아카이브에서 제외됩니다. 예는 예를 참조하십시오.

버전 3.2에서 변경: filter 매개 변수를 추가했습니다.

버전 3.7에서 변경: 재귀는 항목을 정렬된 순서로 추가합니다.

TarFile.addfile(tarinfo, fileobj=None)

Add the TarInfo object tarinfo to the archive. If tarinfo represents a non zero-size regular file, the fileobj argument should be a binary file, and tarinfo.size bytes are read from it and added to the archive. You can create TarInfo objects directly, or by using gettarinfo().

버전 3.13에서 변경: fileobj must be given for non-zero-sized regular files.

TarFile.gettarinfo(name=None, arcname=None, fileobj=None)

기존 파일에서 os.stat()이나 이와 동등한 것의 결과로부터 TarInfo 객체를 만듭니다. 파일은 name으로 이름을 지정하거나, 파일 기술자를 갖는 파일 객체 fileobj로 지정됩니다. name은 경로류 객체일 수 있습니다. 주어지면, arcname은 아카이브에 있는 파일의 대체 이름을 지정하고, 그렇지 않으면, 이름은 fileobj의 name 어트리뷰트나 name 인자에서 취합니다. 이름은 텍스트 문자열이어야 합니다.

addfile()을 사용하여 추가하기 전에 TarInfo의 일부 어트리뷰트를 수정할 수 있습니다. 파일 객체가 파일의 시작 부분에 위치한 일반 파일 객체가 아니면, size와 같은 어트리뷰트를 수정해야 할 수 있습니다. GzipFile과 같은 객체가 이 상황에 해당합니다. name도 수정될 수 있으며, 이 경우 arcname은 더미 문자열일 수 있습니다.

버전 3.6에서 변경: name 매개 변수는 경로류 객체를 받아들입니다.

TarFile.close()

TarFile을 닫습니다. 쓰기 모드에서는, 두 개의 마무리 0블록이 아카이브에 추가됩니다.

TarFile.pax_headers: dict

pax 전역 헤더의 키-값 쌍을 포함하는 딕셔너리.

TarInfo 객체

TarInfo 객체는 TarFile에 있는 하나의 멤버를 나타냅니다. 파일의 모든 필수 어트리뷰트(파일 유형, 크기, 시간, 권한, 소유자 등과 같은)를 저장하는 것 외에도, 파일 유형을 결정하는 유용한 메서드를 제공합니다. 파일의 데이터 자체를 포함하지 않습니다.

TarInfo objects are returned by TarFile’s methods getmember(), getmembers() and gettarinfo().

Modifying the objects returned by getmember() or getmembers() will affect all subsequent operations on the archive. For cases where this is unwanted, you can use copy.copy() or call the replace() method to create a modified copy in one step.

Several attributes can be set to None to indicate that a piece of metadata is unused or unknown. Different TarInfo methods handle None differently:

The extract() or extractall() methods will ignore the corresponding metadata, leaving it set to a default.

addfile() will fail.

list() will print a placeholder string.

class tarfile.TarInfo(name='')

TarInfo 객체를 만듭니다.

classmethod TarInfo.frombuf(buf, encoding, errors)

문자열 버퍼 buf에서 TarInfo 객체를 만들고 반환합니다.

버퍼가 유효하지 않으면 HeaderError를 발생시킵니다.

classmethod TarInfo.fromtarfile(tarfile)

TarFile 객체 tarfile에서 다음 멤버를 읽고 TarInfo 객체로 반환합니다.

TarInfo.tobuf(format=DEFAULT_FORMAT, encoding=ENCODING, errors='surrogateescape')

TarInfo 객체에서 문자열 버퍼를 만듭니다. 인자에 대한 정보는 TarFile 클래스의 생성자를 참조하십시오.

버전 3.2에서 변경: errors 인자의 기본값으로 'surrogateescape'를 사용합니다.

TarInfo 객체에는 다음과 같은 공개 데이터 어트리뷰트가 있습니다:

TarInfo.name: str

아카이브 멤버의 이름

TarInfo.size: int

바이트 단위의 크기.

TarInfo.mtime: int | float

Time of last modification in seconds since the epoch, as in os.stat_result.st_mtime.

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.mode: int

Permission bits, as for os.chmod().

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.type

파일 유형. type은 일반적으로 다음 상수 중 하나입니다: REGTYPE, AREGTYPE, LNKTYPE, SYMTYPE, DIRTYPE, FIFOTYPE, CONTTYPE, CHRTYPE, BLKTYPE, GNUTYPE_SPARSE. TarInfo 객체의 유형을 더 편리하게 결정하려면, 아래 is*() 메서드를 사용하십시오.

TarInfo.linkname: str

대상 파일 이름의 이름, LNKTYPE과 SYMTYPE 유형의 TarInfo 객체에만 존재합니다.

For symbolic links (SYMTYPE), the linkname is relative to the directory that contains the link. For hard links (LNKTYPE), the linkname is relative to the root of the archive.

TarInfo.uid: int

이 멤버를 처음 저장한 사용자의 사용자 ID.

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.gid: int

이 멤버를 처음 저장한 사용자의 그룹 ID.

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.uname: str

사용자 이름.

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.gname: str

그룹 이름.

버전 3.12에서 변경: Can be set to None for extract() and extractall(), causing extraction to skip applying this attribute.

TarInfo.chksum: int

Header checksum.

TarInfo.devmajor: int

Device major number.

TarInfo.devminor: int

Device minor number.

TarInfo.offset: int

The tar header starts here.

TarInfo.offset_data: int

The file’s data starts here.

TarInfo.sparse

Sparse member information.

TarInfo.pax_headers: dict

연관된 pax 확장 헤더의 키-값 쌍을 포함하는 딕셔너리.

TarInfo.replace(name=..., mtime=..., mode=..., linkname=..., uid=..., gid=..., uname=..., gname=..., deep=True)

Added in version 3.12.

Return a new copy of the TarInfo object with the given attributes changed. For example, to return a TarInfo with the group name set to 'staff', use:

new_tarinfo = old_tarinfo.replace(gname='staff')

By default, a deep copy is made. If deep is false, the copy is shallow, i.e. pax_headers and any custom attributes are shared with the original TarInfo object.

TarInfo 객체는 편리한 조회 메서드도 제공합니다:

TarInfo.isfile()

Return True if the TarInfo object is a regular file.

TarInfo.isreg()

isfile()과 같습니다.

TarInfo.isdir()

디렉터리이면 True를 반환합니다.

TarInfo.issym()

심볼릭 링크이면 True를 반환합니다.

TarInfo.islnk()

하드 링크이면 True를 반환합니다.

TarInfo.ischr()

문자 장치이면 True를 반환합니다.

TarInfo.isblk()

블록 장치이면 True를 반환합니다.

TarInfo.isfifo()

FIFO이면 True를 반환합니다.

TarInfo.isdev()

문자 장치, 블록 장치 또는 FIFO 중 하나이면 True를 반환합니다.

Extraction filters

Added in version 3.12.

The tar format is designed to capture all details of a UNIX-like filesystem, which makes it very powerful. Unfortunately, the features make it easy to create tar files that have unintended – and possibly malicious – effects when extracted. For example, extracting a tar file can overwrite arbitrary files in various ways (e.g. by using absolute paths, .. path components, or symlinks that affect later members).

In most cases, the full functionality is not needed. Therefore, tarfile supports extraction filters: a mechanism to limit functionality, and thus mitigate some of the security issues.

경고

None of the available filters blocks all dangerous archive features. Never extract archives from untrusted sources without prior inspection. See also Hints for further verification.

더 보기

PEP 706 [https://peps.python.org/pep-0706/]

Contains further motivation and rationale behind the design.

The filter argument to TarFile.extract() or extractall() can be:

the string 'fully_trusted': Honor all metadata as specified in the archive. Should be used if the user trusts the archive completely, or implements their own complex verification.

the string 'tar': Honor most tar-specific features (i.e. features of UNIX-like filesystems), but block features that are very likely to be surprising or malicious. See tar_filter() for details.

the string 'data': Ignore or block most features specific to UNIX-like filesystems. Intended for extracting cross-platform data archives. See data_filter() for details.

None (default): Use TarFile.extraction_filter.

If that is also None (the default), the 'data' filter will be used.

버전 3.14에서 변경: The default filter is set to data. Previously, the default was equivalent to fully_trusted.

A callable which will be called for each extracted member with a TarInfo describing the member and the destination path to where the archive is extracted (i.e. the same path is used for all members):

filter(member: TarInfo, path: str, /) -> TarInfo | None

The callable is called just before each member is extracted, so it can take the current state of the disk into account. It can:

return a TarInfo object which will be used instead of the metadata in the archive, or

return None, in which case the member will be skipped, or

raise an exception to abort the operation or skip the member, depending on errorlevel. Note that when extraction is aborted, extractall() may leave the archive partially extracted. It does not attempt to clean up.

Default named filters

The pre-defined, named filters are available as functions, so they can be reused in custom filters:

tarfile.fully_trusted_filter(member, path)

Return member unchanged.

This implements the 'fully_trusted' filter.

tarfile.tar_filter(member, path)

Implements the 'tar' filter.

Strip leading slashes (/ and os.sep) from filenames.

Refuse to extract files with absolute paths (in case the name is absolute even after stripping slashes, e.g. C:/foo on Windows). This raises AbsolutePathError.

Refuse to extract files whose absolute path (after following symlinks) would end up outside the destination. This raises OutsideDestinationError.

Clear high mode bits (setuid, setgid, sticky) and group/other write bits (S_IWGRP | S_IWOTH).

Return the modified TarInfo member.

tarfile.data_filter(member, path)

Implements the 'data' filter. In addition to what tar_filter does:

Refuse to extract links (hard or soft) that link to absolute paths, or ones that link outside the destination.

This raises AbsoluteLinkError or LinkOutsideDestinationError.

Note that such files are refused even on platforms that do not support symbolic links.

Refuse to extract device files (including pipes). This raises SpecialFileError.

For regular files, including hard links:

Set the owner read and write permissions (S_IRUSR | S_IWUSR).

Remove the group & other executable permission (S_IXGRP | S_IXOTH) if the owner doesn’t have it (S_IXUSR).

For other files (directories), set mode to None, so that extraction methods skip applying permission bits.

Set user and group info (uid, gid, uname, gname) to None, so that extraction methods skip setting it.

Return the modified TarInfo member.

Note that this filter does not block all dangerous archive features. See Hints for further verification for details.

Filter errors

When a filter refuses to extract a file, it will raise an appropriate exception, a subclass of FilterError. This will abort the extraction if TarFile.errorlevel is 1 or more. With errorlevel=0 the error will be logged and the member will be skipped, but extraction will continue.

Hints for further verification

Even with filter='data', tarfile is not suited for extracting untrusted files without prior inspection. Among other issues, the pre-defined filters do not prevent denial-of-service attacks. Users should do additional checks.

Here is an incomplete list of things to consider:

Extract to a new temporary directory to prevent e.g. exploiting pre-existing links, and to make it easier to clean up after a failed extraction.

When working with untrusted data, use external (e.g. OS-level) limits on disk, memory and CPU usage.

Check filenames against an allow-list of characters (to filter out control characters, confusables, foreign path separators, and so on).

Check that filenames have expected extensions (discouraging files that execute when you “click on them”, or extension-less files like Windows special device names).

Limit the number of extracted files, total size of extracted data, filename length (including symlink length), and size of individual files.

Check for files that would be shadowed on case-insensitive filesystems.

Also note that:

Tar files may contain multiple versions of the same file. Later ones are expected to overwrite any earlier ones. This feature is crucial to allow updating tape archives, but can be abused maliciously.

tarfile does not protect against issues with “live” data, e.g. an attacker tinkering with the destination (or source) directory while extraction (or archiving) is in progress.

Supporting older Python versions

Extraction filters were added to Python 3.12, but may be backported to older versions as security updates. To check whether the feature is available, use e.g. hasattr(tarfile, 'data_filter') rather than checking the Python version.

The following examples show how to support Python versions with and without the feature. Note that setting extraction_filter will affect any subsequent operations.

Fully trusted archive:

my_tarfile.extraction_filter = (lambda member, path: member)
my_tarfile.extractall()

Use the 'data' filter if available, but revert to Python 3.11 behavior ('fully_trusted') if this feature is not available:

my_tarfile.extraction_filter = getattr(tarfile, 'data_filter',
                                       (lambda member, path: member))
my_tarfile.extractall()

Use the 'data' filter; fail if it is not available:

my_tarfile.extractall(filter=tarfile.data_filter)

or:

my_tarfile.extraction_filter = tarfile.data_filter
my_tarfile.extractall()

Use the 'data' filter; warn if it is not available:

if hasattr(tarfile, 'data_filter'):
    my_tarfile.extractall(filter='data')
else:
    # remove this when no longer needed
    warn_the_user('Extracting may be unsafe; consider updating Python')
    my_tarfile.extractall()

Stateful extraction filter example

While tarfile’s extraction methods take a simple filter callable, custom filters may be more complex objects with an internal state. It may be useful to write these as context managers, to be used like this:

with StatefulFilter() as filter_func:
    tar.extractall(path, filter=filter_func)

Such a filter can be written as, for example:

class StatefulFilter:
    def __init__(self):
        self.file_count = 0

    def __enter__(self):
        return self

    def __call__(self, member, path):
        self.file_count += 1
        return member

    def __exit__(self, *exc_info):
        print(f'{self.file_count} files extracted')

명령 줄 인터페이스

Added in version 3.4.

tarfile 모듈은 tar 아카이브와 상호 작용하기 위한 간단한 명령 줄 인터페이스를 제공합니다.

새 tar 아카이브를 만들려면, -c 옵션 뒤에 이름을 지정한 다음 포함해야 하는 파일 이름을 나열하십시오:

$ python -m tarfile -c monty.tar  spam.txt eggs.txt

디렉터리 전달도 허용됩니다:

$ python -m tarfile -c monty.tar life-of-brian_1979/

tar 아카이브를 현재 디렉터리로 추출하려면, -e 옵션을 사용하십시오:

$ python -m tarfile -e monty.tar

디렉터리 이름을 전달하여 tar 아카이브를 다른 디렉터리로 추출할 수도 있습니다:

$ python -m tarfile -e monty.tar  other-dir/

tar 아카이브에 있는 파일 목록을 보려면, -l 옵션을 사용하십시오:

$ python -m tarfile -l monty.tar

명령 줄 옵션

-l <tarfile>

--list <tarfile>

tarfile에 있는 파일을 나열합니다.

-c <tarfile> <source1> ... <sourceN>

--create <tarfile> <source1> ... <sourceN>

소스 파일에서 tarfile을 만듭니다.

-e <tarfile> [<output_dir>]

--extract <tarfile> [<output_dir>]

output_dir이 지정되지 않으면 tarfile을 현재 디렉터리로 추출합니다.

-t <tarfile>

--test <tarfile>

tarfile이 유효한지 테스트합니다.

-v, --verbose

상세한 출력.

--filter <filtername>

Specifies the filter for --extract. See Extraction filters for details. Only string names are accepted (that is, fully_trusted, tar, and data).

예

전체 tar 아카이브를 현재 작업 디렉터리로 추출하는 방법:

import tarfile
tar = tarfile.open("sample.tar.gz")
tar.extractall(filter='data')
tar.close()

리스트 대신 제너레이터 함수를 사용하여 TarFile.extractall()로 tar 아카이브의 부분집합을 추출하는 방법:

import os
import tarfile

def py_files(members):
    for tarinfo in members:
        if os.path.splitext(tarinfo.name)[1] == ".py":
            yield tarinfo

tar = tarfile.open("sample.tar.gz")
tar.extractall(members=py_files(tar))
tar.close()

파일명 리스트로 압축되지 않은 tar 아카이브를 만드는 방법:

import tarfile
tar = tarfile.open("sample.tar", "w")
for name in ["foo", "bar", "quux"]:
    tar.add(name)
tar.close()

with 문을 사용한 같은 예제:

import tarfile
with tarfile.open("sample.tar", "w") as tar:
    for name in ["foo", "bar", "quux"]:
        tar.add(name)

gzip 압축 tar 아카이브를 읽고 일부 멤버 정보를 표시하는 방법:

import tarfile
tar = tarfile.open("sample.tar.gz", "r:gz")
for tarinfo in tar:
    print(tarinfo.name, "is", tarinfo.size, "bytes in size and is ", end="")
    if tarinfo.isreg():
        print("a regular file.")
    elif tarinfo.isdir():
        print("a directory.")
    else:
        print("something else.")
tar.close()

TarFile.add()의 filter 매개 변수를 사용하여 아카이브를 만들고 사용자 정보를 재설정하는 방법:

import tarfile
def reset(tarinfo):
    tarinfo.uid = tarinfo.gid = 0
    tarinfo.uname = tarinfo.gname = "root"
    return tarinfo
tar = tarfile.open("sample.tar.gz", "w:gz")
tar.add("foo", filter=reset)
tar.close()

지원되는 tar 형식

tarfile 모듈로 만들 수 있는 tar 형식은 세 가지입니다:

POSIX.1-1988 ustar 형식 (USTAR_FORMAT). 최대 256자 길이의 파일명과 최대 100자 링크 이름을 지원합니다. 최대 파일 크기는 8 GiB입니다. 이것은 오래되고 제한적이지만 널리 지원되는 형식입니다.

GNU tar 형식 (GNU_FORMAT). 긴 파일명과 링크 이름, 8GiB보다 큰 파일과 스파스(sparse) 파일을 지원합니다. 이것은 GNU/Linux 시스템에서 사실상 표준입니다. tarfile은 긴 이름에 대한 GNU tar 확장을 완전히 지원하며 스파스(sparse) 파일 지원은 읽기 전용입니다.

The POSIX.1-2001 pax format (PAX_FORMAT). It is the most flexible format with virtually no limits. It supports long filenames and linknames, large files and stores pathnames in a portable way. Modern tar implementations, including GNU tar, bsdtar/libarchive and star, fully support extended pax features; some old or unmaintained libraries may not, but should treat pax archives as if they were in the universally supported ustar format. It is the current default format for new archives.

다른 방법으로 저장할 수 없는 정보를 위해 추가 헤더를 사용하여 기존 ustar 형식을 확장합니다. pax 헤더에는 두 가지 종류가 있습니다: 확장(extended) 헤더는 후속 파일 헤더에만 영향을 미치며, 전역(global) 헤더는 전체 아카이브에 유효하며 뒤따르는 파일 모두에 영향을 미칩니다. pax 헤더의 모든 데이터는 이식성의 이유로 UTF-8로 인코딩됩니다.

읽을 수는 있지만 만들 수 없는 tar 형식의 변형이 더 있습니다:

고대 V7 형식. 이것은 일반 파일과 디렉터리 만 저장하는 유닉스 7판(Unix Seventh Edition)에서 온 첫 번째 tar 형식입니다. 이름은 100자 이하여야 합니다. 사용자/그룹 이름 정보는 없습니다. ASCII가 아닌 문자가 있는 필드의 경우 일부 아카이브에서 헤더 체크섬이 잘못 계산되었습니다.

SunOS tar 확장 형식. 이 형식은 POSIX.1-2001 pax 형식의 변형이지만, 호환되지 않습니다.

유니코드 문제

tar 형식은 원래 파일 시스템 정보 보존에 중점을 두고 테이프 드라이브에서 백업하기 위해 고안되었습니다. 현재 tar 아카이브는 일반적으로 파일 배포와 네트워크를 통한 아카이브 교환에 사용됩니다. 원래 형식(다른 모든 형식의 기초)의 한 가지 문제점은 다른 문자 인코딩을 지원한다는 개념이 없다는 것입니다. 예를 들어, UTF-8 시스템에서 만들어진 일반 tar 아카이브는 ASCII가 아닌 문자가 포함되면 Latin-1 시스템에서 올바르게 읽을 수 없습니다. (파일명, 링크 이름, 사용자/그룹 이름과 같은) 텍스트 메타 데이터가 손상된 것으로 나타납니다. 불행히도, 아카이브의 인코딩을 자동 감지하는 방법은 없습니다. pax 형식은 이 문제를 해결하도록 설계되었습니다. 범용 문자 인코딩 UTF-8을 사용하여 ASCII가 아닌 메타 데이터를 저장합니다.

tarfile에서 문자 변환의 세부 사항은 TarFile 클래스의 encoding과 errors 키워드 인자에 의해 제어됩니다.

encoding은 아카이브의 메타 데이터에 사용할 문자 인코딩을 정의합니다. 기본값은 sys.getfilesystemencoding() 이고, 또는 폴 백으로 'ascii'입니다. 아카이브를 읽거나 쓰는지에 따라, 메타 데이터를 디코딩하거나 인코딩해야 합니다. encoding이 올바르게 설정되지 않으면, 이 변환이 실패 할 수 있습니다.

errors 인자는 변환할 수 없는 문자를 처리하는 방법을 정의합니다. 가능한 값은 섹션 에러 처리기에 나열되어 있습니다. 기본 체계는 파이썬은 파일 시스템 호출에도 사용하는 'surrogateescape'입니다, 파일명, 명령 줄 인자 및 환경 변수를 참조하십시오.

PAX_FORMAT 아카이브(기본값)의 경우, 모든 메타 데이터가 UTF-8을 사용하여 저장기 때문에 encoding은 일반적으로 필요하지 않습니다. encoding은 바이너리 pax 헤더가 디코딩되거나 서로게이트 문자가 있는 문자열이 저장될 때와 같은 드문 경우에만 사용됩니다.

파일 형식

이 장에서 설명하는 모듈들은 마크업 언어가 아니고 전자 메일과 무관한 다양한 파일 형식을 구문 분석합니다.

csv — CSV File Reading and Writing

모듈 내용

reader()

writer()

register_dialect()

unregister_dialect()

get_dialect()

list_dialects()

field_size_limit()

DictReader

DictWriter

Dialect

excel

excel_tab

unix_dialect

Sniffer

sniff()

has_header()

QUOTE_ALL

QUOTE_MINIMAL

QUOTE_NONNUMERIC

QUOTE_NONE

QUOTE_NOTNULL

QUOTE_STRINGS

Error

방언과 포매팅 파라미터

delimiter

doublequote

escapechar

lineterminator

quotechar

quoting

skipinitialspace

strict

판독기 객체

__next__()

dialect

line_num

fieldnames

기록기 객체

writerow()

writerows()

dialect

writeheader()

예제

configparser — Configuration file parser

빠른 시작

지원되는 데이터형

대체 값

지원되는 INI 파일 구조

Unnamed Sections

값의 보간

BasicInterpolation

ExtendedInterpolation

매핑 프로토콜 액세스

구문 분석기 동작 사용자 정의

BOOLEAN_STATES

SECTCRE

레거시 API 예제

ConfigParser 객체

ConfigParser

defaults()

sections()

add_section()

has_section()

options()

has_option()

read()

read_file()

read_string()

read_dict()

get()

getint()

getfloat()

getboolean()

items()

set()

write()

remove_option()

remove_section()

optionxform()

UNNAMED_SECTION

MAX_INTERPOLATION_DEPTH

RawConfigParser 객체

RawConfigParser

add_section()

set()

예외

Error

NoSectionError

DuplicateSectionError

DuplicateOptionError

NoOptionError

InterpolationError

InterpolationDepthError

InterpolationMissingOptionError

InterpolationSyntaxError

MissingSectionHeaderError

ParsingError

MultilineContinuationError

UnnamedSectionDisabledError

tomllib — Parse TOML files

load()

loads()

TOMLDecodeError

msg

doc

pos

lineno

colno

Examples

Conversion Table

netrc — netrc file processing

netrc

NetrcParseError

msg

filename

lineno

netrc 객체

authenticators()

__repr__()

hosts

macros

plistlib — Generate and parse Apple .plist files

load()

loads()

dump()

dumps()

UID

FMT_XML

FMT_BINARY

예제

csv — CSV File Reading and Writing

소스 코드: Lib/csv.py [https://github.com/python/cpython/tree/main/Lib/csv.py]

소위 CSV (Comma Separated Values – 쉼표로 구분된 값) 형식은 스프레드시트와 데이터베이스에 대한 가장 일반적인 가져오기 및 내보내기 형식입니다. CSV 형식은 RFC 4180 [https://datatracker.ietf.org/doc/html/rfc4180.html]에서 표준화된 방식으로 형식을 기술하기 전에 여러 해 동안 사용되었습니다. 잘 정의된 표준이 없다는 것은 다른 애플리케이션에 의해 생성되고 소비되는 데이터에 미묘한 차이가 존재한다는 것을 의미합니다. 이러한 차이로 인해 여러 소스의 CSV 파일을 처리하는 것이 번거로울 수 있습니다. 그러나 분리 문자와 인용 문자가 다양하기는 해도, 전체 형식은 유사하여 프로그래머에게 데이터 읽기와 쓰기 세부 사항을 숨기면서도 이러한 데이터를 효율적으로 조작할 수 있는 단일 모듈을 작성하는 것이 가능합니다.

csv 모듈은 CSV 형식의 표 형식 데이터를 읽고 쓰는 클래스를 구현합니다. 이 모듈은 프로그래머가 Excel에서 사용하는 CSV 형식에 대한 자세한 내용을 알지 못해도, “Excel에서 선호하는 형식으로 이 데이터를 쓰세요”나 “Excel에서 생성된 이 파일의 데이터를 읽으세요”라고 말할 수 있도록 합니다. 프로그래머는 다른 응용 프로그램에서 이해할 수 있는 CSV 형식을 기술하거나 자신만의 특수 용도 CSV 형식을 정의할 수 있습니다.

csv 모듈의 reader와 writer 객체는 시퀀스를 읽고 씁니다. 프로그래머는 DictReader와 DictWriter 클래스를 사용하여 딕셔너리 형식으로 데이터를 읽고 쓸 수 있습니다.

더 보기

PEP 305 [https://peps.python.org/pep-0305/] - CSV File API

파이썬에 이 모듈의 추가를 제안한 파이썬 개선 제안.

모듈 내용

csv 모듈은 다음 함수를 정의합니다:

csv.reader(csvfile, dialect='excel', **fmtparams)

Return a reader object that will process lines from the given csvfile. A csvfile must be an iterable of strings, each in the reader’s defined csv format. A csvfile is most commonly a file-like object or list. If csvfile is a file object, it should be opened with newline=''. [1] An optional dialect parameter can be given which is used to define a set of parameters specific to a particular CSV dialect. It may be an instance of a subclass of the Dialect class or one of the strings returned by the list_dialects() function. The other optional fmtparams keyword arguments can be given to override individual formatting parameters in the current dialect. For full details about the dialect and formatting parameters, see section 방언과 포매팅 파라미터.

csv 파일에서 읽은 각 행(row)은 문자열 리스트로 반환됩니다. QUOTE_NONNUMERIC 포맷 옵션을 지정하지 않으면 아무런 자동 데이터형 변환도 수행되지 않습니다 (지정하면 인용되지 않은 필드는 float로 변환됩니다).

간단한 사용 예:

>>> import csv
>>> with open('eggs.csv', newline='') as csvfile:
...     spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
...     for row in spamreader:
...         print(', '.join(row))
Spam, Spam, Spam, Spam, Spam, Baked Beans
Spam, Lovely Spam, Wonderful Spam

csv.writer(csvfile, dialect='excel', **fmtparams)

Return a writer object responsible for converting the user’s data into delimited strings on the given file-like object. csvfile can be any object with a write() method. If csvfile is a file object, it should be opened with newline='' [1]. An optional dialect parameter can be given which is used to define a set of parameters specific to a particular CSV dialect. It may be an instance of a subclass of the Dialect class or one of the strings returned by the list_dialects() function. The other optional fmtparams keyword arguments can be given to override individual formatting parameters in the current dialect. For full details about dialects and formatting parameters, see the 방언과 포매팅 파라미터 section. To make it as easy as possible to interface with modules which implement the DB API, the value None is written as the empty string. While this isn’t a reversible transformation, it makes it easier to dump SQL NULL data values to CSV files without preprocessing the data returned from a cursor.fetch* call. All other non-string data are stringified with str() before being written.

간단한 사용 예:

import csv
with open('eggs.csv', 'w', newline='') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=' ',
                            quotechar='|', quoting=csv.QUOTE_MINIMAL)
    spamwriter.writerow(['Spam'] * 5 + ['Baked Beans'])
    spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])

csv.register_dialect(name[, dialect[, **fmtparams]])

Associate dialect with name. name must be a string. The dialect can be specified either by passing a sub-class of Dialect, or by fmtparams keyword arguments, or both, with keyword arguments overriding parameters of the dialect. For full details about dialects and formatting parameters, see section 방언과 포매팅 파라미터.

csv.unregister_dialect(name)

방언(dialect) 등록소에서 name과 관련된 연관된 방언을 삭제합니다. name이 등록된 방언 이름이 아니면 Error가 발생합니다.

csv.get_dialect(name)

name과 연관된 방언을 반환합니다. name이 등록된 방언 이름이 아니면 Error가 발생합니다. 이 함수는 불변 Dialect를 반환합니다.

csv.list_dialects()

등록된 모든 방언의 이름을 반환합니다.

csv.field_size_limit([new_limit])

구문 분석기가 허락하는 현재의 최대 필드 크기를 반환합니다. new_limit가 주어지면, 이것이 새로운 한계가 됩니다.

csv 모듈은 다음 클래스를 정의합니다:

class csv.DictReader(f, fieldnames=None, restkey=None, restval=None, dialect='excel', *args, **kwds)

일반 판독기처럼 작동하지만 각 행(row)의 정보를 키가 선택적 fieldnames 매개 변수로 지정된 dict로 매핑하는 객체를 만듭니다.

The fieldnames parameter is a sequence. If fieldnames is omitted, the values in the first row of file f will be used as the fieldnames and will be omitted from the results. If fieldnames is provided, they will be used and the first row will be included in the results. Regardless of how the fieldnames are determined, the dictionary preserves their original ordering.

행에 fieldnames보다 많은 필드가 있으면, 나머지 데이터가 리스트에 저장되고 restkey(기본값은 None)로 지정된 필드 이름으로 저장됩니다. 비어 있지 않은 행에 fieldnames보다 필드 수가 적다면, 빠진 값은 restval(기본값은 None)의 값으로 채워집니다.

다른 모든 선택적 또는 키워드 인자는 하부 reader 인스턴스에 전달됩니다.

If the argument passed to fieldnames is an iterator, it will be coerced to a list.

버전 3.6에서 변경: 반환된 행은 이제 OrderedDict 형입니다.

버전 3.8에서 변경: 반환된 행은 이제 dict 형입니다.

간단한 사용 예:

>>> import csv
>>> with open('names.csv', newline='') as csvfile:
...     reader = csv.DictReader(csvfile)
...     for row in reader:
...         print(row['first_name'], row['last_name'])
...
Eric Idle
John Cleese

>>> print(row)
{'first_name': 'John', 'last_name': 'Cleese'}

class csv.DictWriter(f, fieldnames, restval='', extrasaction='raise', dialect='excel', *args, **kwds)

Create an object which operates like a regular writer but maps dictionaries onto output rows. The fieldnames parameter is a sequence of keys that identify the order in which values in the dictionary passed to the writerow() method are written to file f. The optional restval parameter specifies the value to be written if the dictionary is missing a key in fieldnames. If the dictionary passed to the writerow() method contains a key not found in fieldnames, the optional extrasaction parameter indicates what action to take. If it is set to 'raise', the default value, a ValueError is raised. If it is set to 'ignore', extra values in the dictionary are ignored. Any other optional or keyword arguments are passed to the underlying writer instance.

DictReader 클래스와 달리 DictWriter 클래스의 fieldnames 매개 변수는 선택 사항이 아닙니다.

If the argument passed to fieldnames is an iterator, it will be coerced to a list.

간단한 사용 예:

import csv

with open('names.csv', 'w', newline='') as csvfile:
    fieldnames = ['first_name', 'last_name']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    writer.writerow({'first_name': 'Baked', 'last_name': 'Beans'})
    writer.writerow({'first_name': 'Lovely', 'last_name': 'Spam'})
    writer.writerow({'first_name': 'Wonderful', 'last_name': 'Spam'})

class csv.Dialect

The Dialect class is a container class whose attributes contain information for how to handle doublequotes, whitespace, delimiters, etc. Due to the lack of a strict CSV specification, different applications produce subtly different CSV data. Dialect instances define how reader and writer instances behave.

All available Dialect names are returned by list_dialects(), and they can be registered with specific reader and writer classes through their initializer (__init__) functions like this:

import csv

with open('students.csv', 'w', newline='') as csvfile:
    writer = csv.writer(csvfile, dialect='unix')

class csv.excel

excel 클래스는 Excel에서 생성한 CSV 파일의 일반적인 속성을 정의합니다. 방언 이름 'excel'로 등록됩니다.

class csv.excel_tab

excel_tab 클래스는 Excel에서 생성된 TAB 구분 파일의 일반적인 속성을 정의합니다. 방언 이름 'excel-tab'으로 등록됩니다.

class csv.unix_dialect

unix_dialect 클래스는 유닉스 시스템에서 생성된 CSV 파일의 일반적인 속성을 정의합니다. 즉, '\n'을 줄 종결자로 사용하고 모든 필드를 인용 처리합니다. 방언 이름 'unix'로 등록됩니다.

Added in version 3.2.

class csv.Sniffer

Sniffer 클래스는 CSV 파일의 형식을 추론하는 데 사용됩니다.

Sniffer 클래스는 두 가지 메서드를 제공합니다:

sniff(sample, delimiters=None)

지정된 sample을 분석하고 발견된 파라미터를 반영하는 Dialect 서브 클래스를 반환합니다. 선택적인 delimiters 매개 변수를 주면, 가능한 유효한 구분 문자를 포함하는 문자열로 해석됩니다.

has_header(sample)

Analyze the sample text (presumed to be in CSV format) and return True if the first row appears to be a series of column headers. Inspecting each column, one of two key criteria will be considered to estimate if the sample contains a header:

the second through n-th rows contain numeric values

the second through n-th rows contain strings where at least one value’s length differs from that of the putative header of that column.

Twenty rows after the first row are sampled; if more than half of columns + rows meet the criteria, True is returned.

참고

This method is a rough heuristic and may produce both false positives and negatives.

Sniffer 사용 예:

with open('example.csv', newline='') as csvfile:
    dialect = csv.Sniffer().sniff(csvfile.read(1024))
    csvfile.seek(0)
    reader = csv.reader(csvfile, dialect)
    # ... process CSV file contents here ...

csv 모듈은 다음 상수를 정의합니다:

csv.QUOTE_ALL

writer 객체에 모든 필드를 인용 처리하도록 지시합니다.

csv.QUOTE_MINIMAL

writer 객체에 delimiter, quotechar 또는 lineterminator에 들어있는 모든 문자와 같은 특수 문자를 포함하는 필드만 인용 처리하도록 지시합니다.

csv.QUOTE_NONNUMERIC

writer 객체에 모든 숫자가 아닌 필드를 인용 처리하도록 지시합니다.

Instructs reader objects to convert all non-quoted fields to type float.

csv.QUOTE_NONE

writer 객체에 필드를 절대 인용 처리하지 않도록 지시합니다. 출력 데이터에 현재 delimiter가 등장하면, 현재 escapechar 문자를 앞에 붙입니다. escapechar가 설정되지 않았을 때 작성기는 이스케이프 해야 하는 문자가 있으면 Error를 발생시킵니다.

Instructs reader objects to perform no special processing of quote characters.

csv.QUOTE_NOTNULL

Instructs writer objects to quote all fields which are not None. This is similar to QUOTE_ALL, except that if a field value is None an empty (unquoted) string is written.

Instructs reader objects to interpret an empty (unquoted) field as None and to otherwise behave as QUOTE_ALL.

Added in version 3.12.

csv.QUOTE_STRINGS

Instructs writer objects to always place quotes around fields which are strings. This is similar to QUOTE_NONNUMERIC, except that if a field value is None an empty (unquoted) string is written.

Instructs reader objects to interpret an empty (unquoted) string as None and to otherwise behave as QUOTE_NONNUMERIC.

Added in version 3.12.

csv 모듈은 다음 예외를 정의합니다:

exception csv.Error

에러가 감지될 때 모든 함수가 발생시킵니다.

방언과 포매팅 파라미터

To make it easier to specify the format of input and output records, specific formatting parameters are grouped together into dialects. A dialect is a subclass of the Dialect class containing various attributes describing the format of the CSV file. When creating reader or writer objects, the programmer can specify a string or a subclass of the Dialect class as the dialect parameter. In addition to, or instead of, the dialect parameter, the programmer can also specify individual formatting parameters, which have the same names as the attributes defined below for the Dialect class.

방언은 다음 어트리뷰트를 지원합니다:

Dialect.delimiter

필드를 구분하는 데 사용되는 한 문자로 된 문자열. 기본값은 ','입니다.

Dialect.doublequote

필드 안에 나타나는 quotechar의 인스턴스를 인용 처리하는 방법을 제어합니다. True일 때, 문자를 두 개로 늘립니다. False일 때, escapechar를 quotechar의 접두어로 사용합니다. 기본값은 True입니다.

출력 시, doublequote가 False이고 아무런 escapechar가 설정되지 않았으면, 필드에 quotechar가 있으면 Error가 발생합니다.

Dialect.escapechar

quoting이 QUOTE_NONE으로 설정되었을 때 delimiter를, doublequote가 False일 때 quotechar를 이스케이프 하는데 기록기가 사용하는 한 문자로 된 문자열. 판독 시에, escapechar는 뒤따르는 문자에서 특별한 의미를 제거합니다. 기본값은 None이며, 이스케이핑을 비활성화합니다.

버전 3.11에서 변경: An empty escapechar is not allowed.

Dialect.lineterminator

writer에 의해 생성된 행을 종료하는 데 사용되는 문자열. 기본값은 '\r\n'입니다.

참고

reader는 '\r'이나 '\n'을 줄 종료로 인식하도록 하드 코딩되어 있으며, lineterminator를 무시합니다. 이 동작은 앞으로 변경될 수 있습니다.

Dialect.quotechar

delimiter나 quotechar와 같은 특수 문자를 포함하거나 개행 문자를 포함하는 필드를 인용 처리하는 데 사용되는 한 문자라도 된 문자열. 기본값은 '"'입니다.

버전 3.11에서 변경: An empty quotechar is not allowed.

Dialect.quoting

Controls when quotes should be generated by the writer and recognised by the reader. It can take on any of the QUOTE_* constants and defaults to QUOTE_MINIMAL.

Dialect.skipinitialspace

When True, spaces immediately following the delimiter are ignored. The default is False.

Dialect.strict

True일 때, 잘못된 CSV 입력에서 예외 Error를 발생시킵니다. 기본값은 False입니다.

판독기 객체

판독기 객체(DictReader 인스턴스와 reader() 함수에서 반환한 객체)에는 다음과 같은 공용 메서드가 있습니다:

csvreader.__next__()

Return the next row of the reader’s iterable object as a list (if the object was returned from reader()) or a dict (if it is a DictReader instance), parsed according to the current Dialect. Usually you should call this as next(reader).

판독기 객체에는 다음과 같은 공용 어트리뷰트가 있습니다:

csvreader.dialect

구문 분석기가 사용 중인 방언의 읽기 전용 설명.

csvreader.line_num

소스 이터레이터에서 읽은 줄 수. 레코드가 여러 줄에 걸쳐 있을 수 있으므로, 이것은 반환된 레코드 수와 같지 않습니다.

DictReader 객체에는 다음과 같은 공용 어트리뷰트가 있습니다:

DictReader.fieldnames

객체를 만들 때 매개 변수로 전달되지 않았으면, 이 어트리뷰트는 첫 번째 액세스 시나 파일에서 첫 번째 레코드를 읽을 때 초기화됩니다.

기록기 객체

writer objects (DictWriter instances and objects returned by the writer() function) have the following public methods. A row must be an iterable of strings or numbers for writer objects and a dictionary mapping fieldnames to strings or numbers (by passing them through str() first) for DictWriter objects. Note that complex numbers are written out surrounded by parens. This may cause some problems for other programs which read CSV files (assuming they support complex numbers at all).

csvwriter.writerow(row)

Write the row parameter to the writer’s file object, formatted according to the current Dialect. Return the return value of the call to the write method of the underlying file object.

버전 3.5에서 변경: 임의의 이터러블 지원 추가.

csvwriter.writerows(rows)

rows(위에서 설명한 row 객체의 이터러블)에 있는 모든 요소를 현재 방언에 따라 포매팅해서, 기록기의 파일 객체에 씁니다.

기록기 객체에는 다음과 같은 공용 어트리뷰트가 있습니다:

csvwriter.dialect

기록기가 사용 중인 방언의 읽기 전용 설명.

DictWriter 객체의 공용 메서드는 다음과 같습니다:

DictWriter.writeheader()

(생성자에 지정된 대로) 필드 이름을 담은 행을 현재 방언에 따라 포매팅해서, 기록기의 파일 객체에 씁니다. 내부적으로 사용되는 csvwriter.writerow() 호출의 반환 값을 반환합니다.

Added in version 3.2.

버전 3.8에서 변경: writeheader()는 이제 내부적으로 사용하는 csvwriter.writerow() 메서드에서 반환된 값도 반환합니다.

예제

CSV 파일을 읽는 가장 간단한 예:

import csv
with open('some.csv', newline='') as f:
    reader = csv.reader(f)
    for row in reader:
        print(row)

다른 형식의 파일 읽기:

import csv
with open('passwd', newline='') as f:
    reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)
    for row in reader:
        print(row)

대응하는 가장 간단한 쓰기 예는 다음과 같습니다:

import csv
with open('some.csv', 'w', newline='') as f:
    writer = csv.writer(f)
    writer.writerows(someiterable)

Since open() is used to open a CSV file for reading, the file will by default be decoded into unicode using the system default encoding (see locale.getencoding()). To decode a file using a different encoding, use the encoding argument of open:

import csv
with open('some.csv', newline='', encoding='utf-8') as f:
    reader = csv.reader(f)
    for row in reader:
        print(row)

시스템 기본 인코딩 이외의 다른 것으로 쓸 때도 마찬가지입니다: 출력 파일을 열 때 encoding 인자를 지정하십시오.

새로운 방언 등록하기:

import csv
csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)
with open('passwd', newline='') as f:
    reader = csv.reader(f, 'unixpwd')

판독기의 약간 더 고급 사용 — 에러 잡기와 보고:

import csv, sys
filename = 'some.csv'
with open(filename, newline='') as f:
    reader = csv.reader(f)
    try:
        for row in reader:
            print(row)
    except csv.Error as e:
        sys.exit('file {}, line {}: {}'.format(filename, reader.line_num, e))

또한, 모듈이 문자열 구문 분석을 직접 지원하지는 않지만, 쉽게 수행할 수 있습니다:

import csv
for row in csv.reader(['one,two,three']):
    print(row)

각주

[1] (1,2)

newline=''을 지정하지 않으면, 따옴표 처리된 필드에 포함된 줄 넘김 문자가 올바르게 해석되지 않으며, 줄 끝 표시에 \r\n을 사용하는 플랫폼에서 쓸 때 여분의 \r이 추가됩니다. csv 모듈은 자체 (유니버설) 줄 넘김 처리를 하므로, newline=''을 지정하는 것은 항상 안전합니다.

configparser — Configuration file parser

소스 코드: Lib/configparser.py [https://github.com/python/cpython/tree/main/Lib/configparser.py]

이 모듈은 마이크로소프트 윈도우 INI 파일과 유사한 구조를 제공하는 기본 구성 언어를 구현하는 ConfigParser 클래스를 제공합니다. 이를 사용하여 최종 사용자가 쉽게 사용자 정의 할 수 있는 파이썬 프로그램을 작성할 수 있습니다.

참고

이 라이브러리는 윈도우 레지스트리 확장 버전의 INI 문법에 사용된 값-형 접두사를 해석하거나 기록하지 않습니다.

더 보기

Module tomllib

TOML is a well-specified format for application configuration files. It is specifically designed to be an improved version of INI.

모듈 shlex

Support for creating Unix shell-like mini-languages which can also be used for application configuration files.

모듈 json

The json module implements a subset of JavaScript syntax which is sometimes used for configuration, but does not support comments.

빠른 시작

다음과 같은 매우 기본적인 구성 파일을 봅시다:

[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes

[forge.example]
User = hg

[topsecret.server.example]
Port = 50022
ForwardX11 = no

INI 파일의 구조는 다음 섹션에서 설명됩니다. 기본적으로, 파일은 섹션으로 구성되며, 각 섹션에는 값이 있는 키가 포함됩니다. configparser 클래스는 이러한 파일을 읽고 쓸 수 있습니다. 프로그래밍 방식으로 위의 구성 파일을 만드는 것으로 시작하겠습니다.

>>> import configparser
>>> config = configparser.ConfigParser()
>>> config['DEFAULT'] = {'ServerAliveInterval': '45',
...                      'Compression': 'yes',
...                      'CompressionLevel': '9'}
>>> config['forge.example'] = {}
>>> config['forge.example']['User'] = 'hg'
>>> config['topsecret.server.example'] = {}
>>> topsecret = config['topsecret.server.example']
>>> topsecret['Port'] = '50022'     # mutates the parser
>>> topsecret['ForwardX11'] = 'no'  # same here
>>> config['DEFAULT']['ForwardX11'] = 'yes'
>>> with open('example.ini', 'w') as configfile:
...   config.write(configfile)
...

보시다시피, 구성 구문 분석기는 딕셔너리처럼 취급할 수 있습니다. 나중에 설명되는 차이점이 있지만, 동작은 딕셔너리에서 기대하는 것과 매우 비슷합니다.

이제 구성 파일을 만들고 저장했으니, 파일을 다시 읽고 담긴 데이터를 탐색합시다.

>>> config = configparser.ConfigParser()
>>> config.sections()
[]
>>> config.read('example.ini')
['example.ini']
>>> config.sections()
['forge.example', 'topsecret.server.example']
>>> 'forge.example' in config
True
>>> 'python.org' in config
False
>>> config['forge.example']['User']
'hg'
>>> config['DEFAULT']['Compression']
'yes'
>>> topsecret = config['topsecret.server.example']
>>> topsecret['ForwardX11']
'no'
>>> topsecret['Port']
'50022'
>>> for key in config['forge.example']:
...     print(key)
user
compressionlevel
serveraliveinterval
compression
forwardx11
>>> config['forge.example']['ForwardX11']
'yes'

위에서 볼 수 있듯이, API는 매우 간단합니다. 유일한 마법은 DEFAULT 섹션인데, 다른 모든 섹션에 대한 기본값을 제공합니다 [1]. 섹션의 키는 대소 문자를 구분하지 않으며 소문자로 저장됨에 유의하십시오 [1].

It is possible to read several configurations into a single ConfigParser, where the most recently added configuration has the highest priority. Any conflicting keys are taken from the more recent configuration while the previously existing keys are retained. The example below reads in an override.ini file, which will override any conflicting keys from the example.ini file.

[DEFAULT]
ServerAliveInterval = -1

>>> config_override = configparser.ConfigParser()
>>> config_override['DEFAULT'] = {'ServerAliveInterval': '-1'}
>>> with open('override.ini', 'w') as configfile:
...     config_override.write(configfile)
...
>>> config_override = configparser.ConfigParser()
>>> config_override.read(['example.ini', 'override.ini'])
['example.ini', 'override.ini']
>>> print(config_override.get('DEFAULT', 'ServerAliveInterval'))
-1

This behaviour is equivalent to a ConfigParser.read() call with several files passed to the filenames parameter.

지원되는 데이터형

구성 구문 분석기는 구성 파일에 있는 값의 데이터형을 추측하지 않고, 항상 내부적으로 문자열로 저장합니다. 이것은 다른 데이터형이 필요하면, 직접 변환해야 함을 뜻합니다:

>>> int(topsecret['Port'])
50022
>>> float(topsecret['CompressionLevel'])
9.0

이 작업이 매우 흔하기 때문에, 구성 구문 분석기는 정수, 부동 소수점 및 불리언을 처리하는 편리한 게터(getter) 메서드를 제공합니다. 마지막 것이 가장 흥미로운데, bool('False') 가 여전히 True이기 때문에 bool() 에 값을 전달하는 것만으로는 충분치 않기 때문입니다. 이것이 구성 구문 분석기가 getboolean()도 제공하는 이유입니다. 이 메서드는 대소 문자를 구분하지 않으며 'yes'/'no', 'on'/'off', 'true'/'false' 및 '1'/'0'에서 불리언 값을 인식합니다 [1]. 예를 들면:

>>> topsecret.getboolean('ForwardX11')
False
>>> config['forge.example'].getboolean('ForwardX11')
True
>>> config.getboolean('forge.example', 'Compression')
True

getboolean() 외에도, 구성 구문 분석기는 동등한 getint()와 getfloat() 메서드를 제공합니다. 여러분 자신의 변환기를 등록하고 제공된 변환기를 사용자 정의 할 수 있습니다. [1]

대체 값

As with a dictionary, you can use a section’s get() method to provide fallback values:

>>> topsecret.get('Port')
'50022'
>>> topsecret.get('CompressionLevel')
'9'
>>> topsecret.get('Cipher')
>>> topsecret.get('Cipher', '3des-cbc')
'3des-cbc'

Please note that default values have precedence over fallback values. For instance, in our example the 'CompressionLevel' key was specified only in the 'DEFAULT' section. If we try to get it from the section 'topsecret.server.example', we will always get the default, even if we specify a fallback:

>>> topsecret.get('CompressionLevel', '3')
'9'

One more thing to be aware of is that the parser-level get() method provides a custom, more complex interface, maintained for backwards compatibility. When using this method, a fallback value can be provided via the fallback keyword-only argument:

>>> config.get('forge.example', 'monster',
...            fallback='No such things as monsters')
'No such things as monsters'

getint(), getfloat() 및 getboolean() 메서드에 같은 fallback 인자를 사용할 수 있습니다. 예를 들면:

>>> 'BatchMode' in topsecret
False
>>> topsecret.getboolean('BatchMode', fallback=True)
True
>>> config['DEFAULT']['BatchMode'] = 'no'
>>> topsecret.getboolean('BatchMode', fallback=True)
False

지원되는 INI 파일 구조

A configuration file consists of sections, each led by a [section] header, followed by key/value entries separated by a specific string (= or : by default [1]). By default, section names are case sensitive but keys are not [1]. Leading and trailing whitespace is removed from keys and values. Values can be omitted if the parser is configured to allow it [1], in which case the key/value delimiter may also be left out. Values can also span multiple lines, as long as they are indented deeper than the first line of the value. Depending on the parser’s mode, blank lines may be treated as parts of multiline values or ignored.

By default, a valid section name can be any string that does not contain ‘\n’. To change this, see ConfigParser.SECTCRE.

The first section name may be omitted if the parser is configured to allow an unnamed top level section with allow_unnamed_section=True. In this case, the keys/values may be retrieved by UNNAMED_SECTION as in config[UNNAMED_SECTION].

구성 파일에는 특정 문자(기본적으로 #과 ; [1])를 접두사로 붙인 주석이 포함될 수 있습니다. 주석은 주석이 없다면 빈 줄일 곳에 있을 수 있으며, 들여쓰기 될 수 있습니다. [1]

예를 들면:

[Simple Values]
key=value
spaces in keys=allowed
spaces in values=allowed as well
spaces around the delimiter = obviously
you can also use : to delimit keys from values

[All Values Are Strings]
values like this: 1000000
or this: 3.14159265359
are they treated as numbers? : no
integers, floats and booleans are held as: strings
can use the API to get converted values directly: true

[Multiline Values]
chorus: I'm a lumberjack, and I'm okay
    I sleep all night and I work all day

[No Values]
key_without_value
empty string value here =

[You can use comments]
# like this
; or this

# By default only in an empty line.
# Inline comments can be harmful because they prevent users
# from using the delimiting characters as parts of values.
# That being said, this can be customized.

    [Sections Can Be Indented]
        can_values_be_as_well = True
        does_that_mean_anything_special = False
        purpose = formatting for readability
        multiline_values = are
            handled just fine as
            long as they are indented
            deeper than the first line
            of a value
        # Did I mention we can indent comments, too?

Unnamed Sections

The name of the first section (or unique) may be omitted and values retrieved by the UNNAMED_SECTION attribute.

>>> config = """
... option = value
...
... [  Section 2  ]
... another = val
... """
>>> unnamed = configparser.ConfigParser(allow_unnamed_section=True)
>>> unnamed.read_string(config)
>>> unnamed.get(configparser.UNNAMED_SECTION, 'option')
'value'

값의 보간

핵심 기능 위에, ConfigParser는 보간(interpolation)을 지원합니다. 이는 get() 호출에서 값을 반환하기 전에 값을 전처리할 수 있음을 의미합니다.

class configparser.BasicInterpolation

ConfigParser에서 사용되는 기본 구현. 같은 섹션의 다른 값이나 특수한 기본 섹션의 값을 참조하는 포맷 문자열을 포함하는 값을 사용할 수 있도록 합니다 [1]. 초기화할 때 추가 기본값을 제공할 수 있습니다.

예를 들면:

[Paths]
home_dir: /Users
my_dir: %(home_dir)s/lumberjack
my_pictures: %(my_dir)s/Pictures

[Escape]
# use a %% to escape the % sign (% is the only character that needs to be escaped):
gain: 80%%

위의 예에서, interpolation이 BasicInterpolation() 으로 설정된 ConfigParser는 %(home_dir)s를 home_dir의 값(이 경우 /Users)으로 해석합니다. 결과적으로 %(my_dir)s는 /Users/lumberjack으로 해석됩니다. 모든 보간은 요청 시 수행되므로 참조 체인에 사용된 키를 구성 파일에서 특정 순서로 지정할 필요는 없습니다.

interpolation을 None으로 설정하면, 구문 분석기는 my_pictures의 값을 %(my_dir)s/Pictures로, my_dir의 값을 %(home_dir)s/lumberjack으로 반환합니다.

class configparser.ExtendedInterpolation

예를 들어 zc.buildout에서 사용되는 고급 문법을 구현하는 보간 대체 처리기. 확장 보간은 ${section:option}을 사용하여 외부 섹션의 값을 나타냅니다. 보간은 여러 수준으로 확장될 수 있습니다. 편의상, section: 부분을 생략하면, 보간은 현재 섹션(그리고 가능하면 특수 섹션의 기본값)으로 기본 설정됩니다.

예를 들어, 기본 보간으로 위에서 지정한 구성은, 확장 보간으로는 다음과 같습니다:

[Paths]
home_dir: /Users
my_dir: ${home_dir}/lumberjack
my_pictures: ${my_dir}/Pictures

[Escape]
# use a $$ to escape the $ sign ($ is the only character that needs to be escaped):
cost: $$80

다른 섹션의 값도 가져올 수 있습니다:

[Common]
home_dir: /Users
library_dir: /Library
system_dir: /System
macports_dir: /opt/local

[Frameworks]
Python: 3.2
path: ${Common:system_dir}/Library/Frameworks/

[Arthur]
nickname: Two Sheds
last_name: Jackson
my_dir: ${Common:home_dir}/twosheds
my_pictures: ${my_dir}/Pictures
python_dir: ${Frameworks:path}/Python/Versions/${Frameworks:Python}

매핑 프로토콜 액세스

Added in version 3.2.

매핑 프로토콜 액세스는 사용자 정의 객체를 딕셔너리처럼 사용하는 기능의 일반적인 이름입니다. configparser의 경우, 매핑 인터페이스 구현은 parser['section']['option'] 표기법을 사용합니다.

parser['section']은 특히 구문 분석기의 섹션 데이터에 대한 프락시를 반환합니다. 이는 값은 복사되지 않지만 필요할 때 원래 구문 분석기에서 가져옴을 뜻합니다. 더욱 중요한 것은 섹션 프락시에서 값이 변경되면, 실제로 원래 구문 분석기에서 변경된다는 것입니다.

configparser 객체는 가능한 한 실제 딕셔너리에 가깝게 동작합니다. 매핑 인터페이스가 완전하며 MutableMapping ABC를 준수합니다. 그러나, 고려해야 하는 몇 가지 차이점이 있습니다:

기본적으로, 섹션의 모든 키는 대소 문자를 구분하지 않고 액세스 할 수 있습니다 [1]. 예를 들어 for option in parser["section"]는 optionxform 변환된 옵션 키 이름만 산출합니다. 이것은 기본적으로 소문자 키를 의미합니다. 동시에, 키 'a'를 보유하는 섹션의 경우, 두 표현식 모두 True를 반환합니다:

"a" in parser["section"]
"A" in parser["section"]

모든 섹션에는 DEFAULTSECT 값도 포함되어 있는데, 섹션에 대한 .clear()가 섹션을 비어 보이게 만들 수 없다는 뜻입니다. 이것은 섹션에서 기본값을 삭제할 수 없기 때문입니다 (기술적으로는 기본값이 거기 없기 때문입니다). 섹션에서 재정의되었으면, 삭제하면 기본값이 다시 보입니다. 기본값을 삭제하려고 하면 KeyError가 발생합니다.

DEFAULTSECT는 구문 분석기에서 제거할 수 없습니다:

삭제하려고 하면 ValueError가 발생합니다,

parser.clear()는 이것을 그대로 남겨둡니다,

parser.popitem()은 이것을 절대 반환하지 않습니다.

parser.get(section, option, **kwargs) - 두 번째 인자는 대체 값이 아닙니다. 그러나 섹션 수준 get() 메서드는 매핑 프로토콜과 클래식 configparser API와 모두 호환됨에 유의하십시오.

parser.items()는 매핑 프로토콜과 호환됩니다 (DEFAULTSECT를 포함하여 section_name, section_proxy 쌍의 리스트를 반환합니다). 그러나, 이 메서드는 인자와 함께 호출 할 수도 있습니다: parser.items(section, raw, vars). 후자의 호출은 지정된 section에 대한 option, value 쌍의 리스트를 반환하며, 모든 보간이 확장됩니다 (raw=True가 제공되지 않는 한).

매핑 프로토콜은 기존 레거시 API 위에 구현되므로 원래 인터페이스를 재정의하는 서브 클래스에서도 여전히 매핑이 작동해야 합니다.

구문 분석기 동작 사용자 정의

INI 형식을 사용하는 응용 프로그램만큼이나 많은 INI 형식 변형이 있습니다. configparser는 사용 가능한 가장 큰 INI 스타일 집합을 지원하기 위해 먼 길을 갔습니다. 기본 기능은 주로 역사적 배경에 의해 결정되며 일부 기능을 사용자 정의하고 싶을 가능성이 큽니다.

The most common way to change the way a specific config parser works is to use the __init__() options:

defaults, 기본값: None

이 옵션은 처음에 DEFAULT 섹션에 배치될 키-값 쌍의 딕셔너리를 받아들입니다. 이것은 지정하지 않으면 설명된 기본값과 같은 값이 되는 간결한 구성 파일을 지원하는 우아한 방법입니다.

Hint: if you want to specify default values for a specific section, use read_dict() before you read the actual file.

dict_type, 기본값: dict

이 옵션은 매핑 프로토콜의 작동 방식과 기록된 구성 파일의 꼴에 큰 영향을 미칩니다. 표준 딕셔너리를 사용하면, 모든 섹션이 구문 분석기에 추가된 순서대로 저장됩니다. 섹션 내의 옵션도 마찬가지입니다.

대체 딕셔너리 형을 사용하여 예를 들어 다시 쓸 때 섹션과 옵션을 정렬할 수 있습니다.

참고: 단일 연산에서 키-값 쌍의 집합을 추가하는 방법이 있습니다. 이러한 연산에서 일반 딕셔너리를 사용하면 키 순서가 유지됩니다. 예를 들면:

>>> parser = configparser.ConfigParser()
>>> parser.read_dict({'section1': {'key1': 'value1',
...                                'key2': 'value2',
...                                'key3': 'value3'},
...                   'section2': {'keyA': 'valueA',
...                                'keyB': 'valueB',
...                                'keyC': 'valueC'},
...                   'section3': {'foo': 'x',
...                                'bar': 'y',
...                                'baz': 'z'}
... })
>>> parser.sections()
['section1', 'section2', 'section3']
>>> [option for option in parser['section3']]
['foo', 'bar', 'baz']

allow_no_value, 기본값: False

일부 구성 파일에는 값이 없는 설정이 포함되어 있지만, 그 외에는 configparser 에서 지원하는 구문을 준수하는 것으로 알려져 있습니다. 생성자에 대한 allow_no_value 매개 변수를 사용하여 이러한 값을 받아들여야 함을 표시할 수 있습니다:

>>> import configparser

>>> sample_config = """
... [mysqld]
...   user = mysql
...   pid-file = /var/run/mysqld/mysqld.pid
...   skip-external-locking
...   old_passwords = 1
...   skip-bdb
...   # we don't need ACID today
...   skip-innodb
... """
>>> config = configparser.ConfigParser(allow_no_value=True)
>>> config.read_string(sample_config)

>>> # Settings with values are treated as before:
>>> config["mysqld"]["user"]
'mysql'

>>> # Settings without values provide None:
>>> config["mysqld"]["skip-bdb"]

>>> # Settings which aren't specified still raise an error:
>>> config["mysqld"]["does-not-exist"]
Traceback (most recent call last):
  ...
KeyError: 'does-not-exist'

delimiters, 기본값: ('=', ':')

구분자(delimiters)는 섹션 내의 값에서 키를 구분하는 부분 문자열입니다. 줄에서 처음 나타나는 구분하는 부분 문자열을 구분자로 간주합니다. 이는 값에 (하지만 키는 아닙니다) 구분자가 포함될 수 있음을 의미합니다.

ConfigParser.write()에 대한 space_around_delimiters 인자도 참조하십시오.

comment_prefixes, 기본값: ('#', ';')

inline_comment_prefixes, 기본값 : None

주석 접두사는 구성 파일 내에서 유효한 주석의 시작을 나타내는 문자열입니다. comment_prefixes는 주석이 없으면 빈 줄일 때만 (선택적으로 들여쓰기 됩니다) 사용되는 반면 inline_comment_prefixes는 모든 유효한 값 (예를 들어 섹션 이름, 옵션 및 빈 줄 역시) 뒤에 사용될 수 있습니다. 기본적으로 인라인 주석은 비활성화되어 있으며 '#'과 ';'이 전체 줄 주석의 접두사로 사용됩니다.

버전 3.2에서 변경: configparser의 이전 버전에서는 동작이 comment_prefixes=('#',';')와 inline_comment_prefixes=(';',)와 일치했습니다.

구성 구문 분석기는 주석 접두사 이스케이프를 지원하지 않아서 inline_comment_prefixes를 사용하면 사용자가 주석 접두사로 사용되는 문자로 옵션값을 지정하지 못할 수 있습니다. 확실하지 않으면, inline_comment_prefixes를 설정하지 마십시오. 어떤 상황에서든, 여러 줄 값에서 줄의 시작 부분에 주석 접두사 문자를 저장하는 유일한 방법은 접두사를 보간하는 것입니다, 예를 들어:

>>> from configparser import ConfigParser, ExtendedInterpolation
>>> parser = ConfigParser(interpolation=ExtendedInterpolation())
>>> # the default BasicInterpolation could be used as well
>>> parser.read_string("""
... [DEFAULT]
... hash = #
...
... [hashes]
... shebang =
...   ${hash}!/usr/bin/env python
...   ${hash} -*- coding: utf-8 -*-
...
... extensions =
...   enabled_extension
...   another_extension
...   #disabled_by_comment
...   yet_another_extension
...
... interpolation not necessary = if # is not at line start
... even in multiline values = line #1
...   line #2
...   line #3
... """)
>>> print(parser['hashes']['shebang'])

#!/usr/bin/env python
# -*- coding: utf-8 -*-
>>> print(parser['hashes']['extensions'])

enabled_extension
another_extension
yet_another_extension
>>> print(parser['hashes']['interpolation not necessary'])
if # is not at line start
>>> print(parser['hashes']['even in multiline values'])
line #1
line #2
line #3

strict, 기본값: True

When set to True, the parser will not allow for any section or option duplicates while reading from a single source (using read_file(), read_string() or read_dict()). It is recommended to use strict parsers in new applications.

버전 3.2에서 변경: configparser의 이전 버전에서는 동작이 strict=False와 일치했습니다.

empty_lines_in_values, 기본값: True

구성 구문 분석기에서는, 값을 담는 키보다 많이 들여쓰기만 하면 값이 여러 줄에 걸쳐있을 수 있습니다. 기본적으로 구문 분석기는 빈 줄도 값의 일부가 되도록 합니다. 동시에, 가독성을 높이기 위해 키를 임의로 들여 쓸 수 있습니다. 결과적으로, 구성 파일이 커지고 복잡해지면, 사용자가 파일 구조를 쉽게 놓칠 수 있습니다. 예를 들어 봅시다:

[Section]
key = multiline
  value with a gotcha

 this = is still a part of the multiline value of 'key'

이것은 사용자가 가변 폭 글꼴을 사용하여 파일을 편집하고 있다면, 보는 데 특히 문제가 될 수 있습니다. 따라서 응용 프로그램에 빈 줄이 있는 값이 필요하지 않으면, 허용하지 않는 것이 좋습니다. 이렇게 하면 빈 줄이 매번 키를 분리합니다. 위의 예에서는, key와 this의 두 키를 생성합니다.

default_section, 기본값: configparser.DEFAULTSECT (즉: "DEFAULT")

다른 섹션이나 보간 목적으로 기본값의 특수한 섹션을 허용하는 규칙은 이 라이브러리의 강력한 개념으로, 사용자가 복잡한 선언적 구성을 만들 수 있도록 합니다. 이 섹션은 일반적으로 "DEFAULT"라고 하지만 다른 유효한 섹션 이름을 가리키도록 사용자 정의할 수 있습니다. 몇 가지 흔한 값은 이렇습니다: "general"이나 "common". 제공된 이름은 모든 소스에서 읽을 때 기본값 섹션을 인식하는 데 사용되며 구성을 파일에 다시 쓸 때 사용됩니다. 현재 값은 parser_instance.default_section 어트리뷰트를 사용하여 꺼낼 수 있으며 실행 시간에 수정될 수 있습니다 (즉 파일을 한 형식에서 다른 형식으로 변환하기 위해).

interpolation, 기본값: configparser.BasicInterpolation

interpolation 인자를 통해 사용자 정의 처리기를 제공하여 보간 동작을 사용자 정의할 수 있습니다. None은 보간을 완전히 끄는 데 사용할 수 있으며, ExtendedInterpolation() 은 zc.buildout에서 영감을 얻은 고급 변형을 제공합니다. 이 주제에 관한 자세한 내용은 전용 설명서 섹션에 있습니다. RawConfigParser 의 기본값은 None입니다.

converters, 기본값: 설정되지 않음

Config parsers provide option value getters that perform type conversion. By default getint(), getfloat(), and getboolean() are implemented. Should other getters be desirable, users may define them in a subclass or pass a dictionary where each key is a name of the converter and each value is a callable implementing said conversion. For instance, passing {'decimal': decimal.Decimal} would add getdecimal() on both the parser object and all section proxies. In other words, it will be possible to write both parser_instance.getdecimal('section', 'key', fallback=0) and parser_instance['section'].getdecimal('key', 0).

변환기가 구문 분석기의 상태에 액세스해야 하면, 구성 구문 분석기 서브 클래스에서 메서드로 구현될 수 있습니다. 이 메서드의 이름이 get으로 시작하면, 모든 섹션 프락시에서 dict 호환 형식으로 사용할 수 있습니다 (위의 getdecimal() 예를 참조하십시오).

이러한 구문 분석기 어트리뷰트의 기본값을 재정의하여 더 고급 사용자 정의를 수행할 수 있습니다. 기본값은 클래스에서 정의되므로, 서브 클래스나 어트리뷰트 대입으로 재정의할 수 있습니다.

ConfigParser.BOOLEAN_STATES

getboolean()을 사용할 때 기본적으로, 구성 구문 분석기는 다음 값들을 True로 간주하고: '1', 'yes', 'true', 'on' 다음 값들을 False로 간주합니다: '0', 'no', 'false', 'off'. 문자열과 불리언 결과를 사용자 정의 딕셔너리로 지정하여 이를 재정의할 수 있습니다. 예를 들면:

>>> custom = configparser.ConfigParser()
>>> custom['section1'] = {'funky': 'nope'}
>>> custom['section1'].getboolean('funky')
Traceback (most recent call last):
...
ValueError: Not a boolean: nope
>>> custom.BOOLEAN_STATES = {'sure': True, 'nope': False}
>>> custom['section1'].getboolean('funky')
False

다른 일반적인 불리언 쌍에는 accept/reject나 enabled/disabled가 포함됩니다.

ConfigParser.optionxform(option)

이 메서드는 모든 읽기, get 또는 set 연산에서 옵션 이름을 변환합니다. 기본값은 이름을 소문자로 변환합니다. 이는 또한 구성 파일을 기록할 때 모든 키가 소문자가 됨을 의미합니다. 이것이 부적절하다면 이 메서드를 재정의하십시오. 예를 들면:

>>> config = """
... [Section1]
... Key = Value
...
... [Section2]
... AnotherKey = Value
... """
>>> typical = configparser.ConfigParser()
>>> typical.read_string(config)
>>> list(typical['Section1'].keys())
['key']
>>> list(typical['Section2'].keys())
['anotherkey']
>>> custom = configparser.RawConfigParser()
>>> custom.optionxform = lambda option: option
>>> custom.read_string(config)
>>> list(custom['Section1'].keys())
['Key']
>>> list(custom['Section2'].keys())
['AnotherKey']

참고

optionxform 함수는 옵션 이름을 규범적 형식으로 변환합니다. 이 함수는 멱등적(idempotent) 함수여야 합니다: 이름이 이미 규범적 형식이면, 변경되지 않은 상태로 반환해야 합니다.

ConfigParser.SECTCRE

섹션 헤더를 구문 분석하는 데 사용되는 컴파일된 정규식. 기본값은 [section]을 이름 "section"과 일치시킵니다. 공백은 섹션 이름의 일부로 간주해서, [  larch  ]는 이름이 "  larch  "인 섹션으로 읽힙니다. 이것이 부적절하다면 이 어트리뷰트를 재정의하십시오. 예를 들면:

>>> import re
>>> config = """
... [Section 1]
... option = value
...
... [  Section 2  ]
... another = val
... """
>>> typical = configparser.ConfigParser()
>>> typical.read_string(config)
>>> typical.sections()
['Section 1', '  Section 2  ']
>>> custom = configparser.ConfigParser()
>>> custom.SECTCRE = re.compile(r"\[ *(?P<header>[^]]+?) *\]")
>>> custom.read_string(config)
>>> custom.sections()
['Section 1', 'Section 2']

참고

ConfigParser 객체는 옵션 줄을 인식하기 위해 OPTCRE 어트리뷰트도 사용하지만, 생성자 옵션 allow_no_value와 delimiters를 방해하기 때문에 재정의하지 않는 것이 좋습니다.

레거시 API 예제

주로 이전 버전과의 호환성 문제로 인해, configparser는 명시적인 get/set 메서드로 레거시 API도 제공합니다. 아래에 설명된 메서드에 대한 유효한 사용 사례가 있지만, 새 프로젝트에는 매핑 프로토콜 액세스가 선호됩니다. 레거시 API는 때때로 더 고급이고, 저수준(low-level)이며 완전히 반 직관적입니다.

구성 파일에 쓰는 예:

import configparser

config = configparser.RawConfigParser()

# Please note that using RawConfigParser's set functions, you can assign
# non-string values to keys internally, but will receive an error when
# attempting to write to a file or when you get it in non-raw mode. Setting
# values using the mapping protocol or ConfigParser's set() does not allow
# such assignments to take place.
config.add_section('Section1')
config.set('Section1', 'an_int', '15')
config.set('Section1', 'a_bool', 'true')
config.set('Section1', 'a_float', '3.1415')
config.set('Section1', 'baz', 'fun')
config.set('Section1', 'bar', 'Python')
config.set('Section1', 'foo', '%(bar)s is %(baz)s!')

# Writing our configuration file to 'example.cfg'
with open('example.cfg', 'w') as configfile:
    config.write(configfile)

구성 파일을 다시 읽는 예:

import configparser

config = configparser.RawConfigParser()
config.read('example.cfg')

# getfloat() raises an exception if the value is not a float
# getint() and getboolean() also do this for their respective types
a_float = config.getfloat('Section1', 'a_float')
an_int = config.getint('Section1', 'an_int')
print(a_float + an_int)

# Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'.
# This is because we are using a RawConfigParser().
if config.getboolean('Section1', 'a_bool'):
    print(config.get('Section1', 'foo'))

보간을 얻으려면, ConfigParser를 사용하십시오:

import configparser

cfg = configparser.ConfigParser()
cfg.read('example.cfg')

# Set the optional *raw* argument of get() to True if you wish to disable
# interpolation in a single get operation.
print(cfg.get('Section1', 'foo', raw=False))  # -> "Python is fun!"
print(cfg.get('Section1', 'foo', raw=True))   # -> "%(bar)s is %(baz)s!"

# The optional *vars* argument is a dict with members that will take
# precedence in interpolation.
print(cfg.get('Section1', 'foo', vars={'bar': 'Documentation',
                                       'baz': 'evil'}))

# The optional *fallback* argument can be used to provide a fallback value
print(cfg.get('Section1', 'foo'))
      # -> "Python is fun!"

print(cfg.get('Section1', 'foo', fallback='Monty is not.'))
      # -> "Python is fun!"

print(cfg.get('Section1', 'monster', fallback='No such things as monsters.'))
      # -> "No such things as monsters."

# A bare print(cfg.get('Section1', 'monster')) would raise NoOptionError
# but we can also use:

print(cfg.get('Section1', 'monster', fallback=None))
      # -> None

기본값은 두 가지 유형의 ConfigParser 모두에서 사용할 수 있습니다. 사용된 옵션이 다른 곳에 정의되어 있지 않으면 보간에 사용됩니다.

import configparser

# New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' each
config = configparser.ConfigParser({'bar': 'Life', 'baz': 'hard'})
config.read('example.cfg')

print(config.get('Section1', 'foo'))     # -> "Python is fun!"
config.remove_option('Section1', 'bar')
config.remove_option('Section1', 'baz')
print(config.get('Section1', 'foo'))     # -> "Life is hard!"

ConfigParser 객체

class configparser.ConfigParser(defaults=None, dict_type=dict, allow_no_value=False, *, delimiters=('=', ':'), comment_prefixes=('#', ';'), inline_comment_prefixes=None, strict=True, empty_lines_in_values=True, default_section=configparser.DEFAULTSECT, interpolation=BasicInterpolation(), converters={}, allow_unnamed_section=False)

메인 구성 구문 분석기. defaults가 주어지면, 내장 기본값의 딕셔너리로 초기화됩니다. dict_type이 제공되면, 섹션 리스트, 섹션 내의 옵션 및 기본값에 대한 딕셔너리 객체를 만드는 데 사용됩니다.

delimiters가 주어지면, 키를 값과 나누는 부분 문자열 집합으로 사용됩니다. comment_prefixes가 주어지면, 주석이 없다면 빈 줄일 곳에서 주석을 시작하는 접두사의 부분 문자열 집합으로 사용됩니다. 주석은 들여 쓸 수 있습니다. inline_comment_prefixes가 주어지면, 비어 있지 않은 줄에서 주석을 시작하는 접두사의 부분 문자열 집합으로 사용됩니다.

strict가 True(기본값)이면, 구문 분석기는 단일 소스(파일, 문자열 또는 딕셔너리)에서 읽는 동안 섹션이나 옵션의 중복을 허용하지 않고, DuplicateSectionError 나 DuplicateOptionError를 발생시킵니다. empty_lines_in_values가 False이면 (기본값: True), 각 빈 줄은 옵션의 끝을 나타냅니다. 그렇지 않으면, 여러 줄 옵션의 내부 빈 줄이 값의 일부로 유지됩니다. allow_no_value가 True이면 (기본값: False), 값이 없는 옵션이 허용됩니다; 이들에 대해 저장되는 값은 None이며 후행 구분자 없이 직렬화됩니다.

When default_section is given, it specifies the name for the special section holding default values for other sections and interpolation purposes (normally named "DEFAULT"). This value can be retrieved and changed at runtime using the default_section instance attribute. This won’t re-evaluate an already parsed config file, but will be used when writing parsed settings to a new config file.

interpolation 인자를 통해 사용자 정의 처리기를 제공하여 보간 동작을 사용자 정의할 수 있습니다. None은 보간을 완전히 끄는 데 사용할 수 있으며, ExtendedInterpolation() 은 zc.buildout에서 영감을 얻은 고급 변형을 제공합니다. 이 주제에 관한 자세한 내용은 전용 설명서 섹션에 있습니다.

보간에 사용된 모든 옵션 이름은 다른 옵션 이름 참조와 마찬가지로 optionxform() 메서드를 통해 전달됩니다. 예를 들어, (옵션 이름을 소문자로 변환하는) optionxform()의 기본 구현을 사용하면, 값 foo %(bar)s와 foo %(BAR)s가 동등합니다.

When converters is given, it should be a dictionary where each key represents the name of a type converter and each value is a callable implementing the conversion from string to the desired datatype. Every converter gets its own corresponding get*() method on the parser object and section proxies.

When allow_unnamed_section is True (default: False), the first section name can be omitted. See the “Unnamed Sections” section.

It is possible to read several configurations into a single ConfigParser, where the most recently added configuration has the highest priority. Any conflicting keys are taken from the more recent configuration while the previously existing keys are retained. The example below reads in an override.ini file, which will override any conflicting keys from the example.ini file.

[DEFAULT]
ServerAliveInterval = -1

>>> config_override = configparser.ConfigParser()
>>> config_override['DEFAULT'] = {'ServerAliveInterval': '-1'}
>>> with open('override.ini', 'w') as configfile:
...     config_override.write(configfile)
...
>>> config_override = configparser.ConfigParser()
>>> config_override.read(['example.ini', 'override.ini'])
['example.ini', 'override.ini']
>>> print(config_override.get('DEFAULT', 'ServerAliveInterval'))
-1

버전 3.1에서 변경: 기본 dict_type은 collections.OrderedDict입니다.

버전 3.2에서 변경: allow_no_value, delimiters, comment_prefixes, strict, empty_lines_in_values, default_section 및 interpolation이 추가되었습니다.

버전 3.5에서 변경: converters 인자가 추가되었습니다.

버전 3.7에서 변경: The defaults argument is read with read_dict(), providing consistent behavior across the parser: non-string keys and values are implicitly converted to strings.

버전 3.8에서 변경: 이제 삽입 순서를 유지하므로, 기본 dict_type은 dict입니다.

버전 3.13에서 변경: Raise a MultilineContinuationError when allow_no_value is True, and a key without a value is continued with an indented line.

버전 3.13에서 변경: The allow_unnamed_section argument was added.

defaults()

인스턴스 전체 기본값을 포함하는 딕셔너리를 반환합니다.

sections()

사용 가능한 섹션 리스트를 반환합니다; 기본값 섹션은 리스트에 포함되지 않습니다.

add_section(section)

section이라는 섹션을 인스턴스에 추가합니다. 주어진 이름의 섹션이 이미 존재하면, DuplicateSectionError 가 발생합니다. 기본값 섹션 이름이 전달되면, ValueError가 발생합니다. 섹션의 이름은 문자열이어야 합니다; 그렇지 않으면, TypeError가 발생합니다.

버전 3.2에서 변경: 문자열이 아닌 섹션 이름은 TypeError를 발생시킵니다.

has_section(section)

이름 지정된 section이 구성에 있는지를 나타냅니다. 기본값 섹션은 인정되지 않습니다.

options(section)

지정된 section에서 사용 가능한 옵션 리스트를 반환합니다.

has_option(section, option)

주어진 section이 존재하고, 주어진 option을 포함하면, True를 반환합니다; 그렇지 않으면 False를 반환합니다. 지정된 section이 None이거나 빈 문자열이면, DEFAULT로 가정합니다.

read(filenames, encoding=None)

파일명들의 이터러블을 읽고 구문 분석하여, 성공적으로 구문 분석된 파일명의 리스트를 반환합니다.

filenames가 문자열, bytes 객체 또는 경로류 객체이면 단일 파일명으로 처리됩니다. filenames에서 이름 지정된 파일을 열 수 없으면, 해당 파일은 무시됩니다. 이는 잠재적인 구성 파일 위치(예를 들어, 현재 디렉터리, 사용자의 홈 디렉터리 및 일부 시스템 전체 디렉터리)의 이터러블을 지정할 수 있도록 설계되었으며, 이터러블에 있는 존재하는 모든 구성 파일을 읽습니다.

제공된 이름의 파일이 아무것도 없으면, ConfigParser 인스턴스는 빈 데이터 집합을 포함합니다. 파일에서 초깃값을 로드해야 하는 응용 프로그램은 선택적 파일에 대해 read()를 호출하기 전에 read_file()을 사용하여 필수 파일을 로드해야 합니다:

import configparser, os

config = configparser.ConfigParser()
config.read_file(open('defaults.cfg'))
config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')],
            encoding='cp1250')

버전 3.2에서 변경: Added the encoding parameter. Previously, all files were read using the default encoding for open().

버전 3.6.1에서 변경: filenames 매개 변수는 경로류 객체를 받아들입니다.

버전 3.7에서 변경: filenames 매개 변수는 bytes 객체를 받아들입니다.

read_file(f, source=None)

f에서 구성 데이터를 읽고 구문 분석합니다. f는 유니코드 문자열을 산출하는 이터러블 이어야 합니다 (예를 들어 텍스트 모드로 열린 파일).

Optional argument source specifies the name of the file being read. If not given and f has a name attribute, that is used for source; the default is '<???>'.

Added in version 3.2: Replaces readfp().

read_string(string, source='<string>')

문자열에서 구성 데이터를 구문 분석합니다.

선택적 인자 source는 전달된 string의 문맥 특정 이름을 지정합니다. 지정하지 않으면, '<string>'이 사용됩니다. 일반적으로 파일 시스템 경로나 URL이어야 합니다.

Added in version 3.2.

read_dict(dictionary, source='<dict>')

딕셔너리와 같은 items() 메서드를 제공하는 임의의 객체에서 구성을 로드합니다. 키는 섹션 이름이며, 값은 섹션에 있어야 하는 키와 값이 들어 있는 딕셔너리입니다. 사용된 딕셔너리 형이 순서를 유지하면, 섹션과 해당 키가 순서대로 추가됩니다. 값은 자동으로 문자열로 변환됩니다.

선택적 인자 source는 전달된 dictionary의 문맥 특정 이름을 지정합니다. 지정하지 않으면, <dict>가 사용됩니다.

이 메서드를 사용하면 구문 분석 기간에 상태를 복사할 수 있습니다.

Added in version 3.2.

get(section, option, *, raw=False, vars=None[, fallback])

명명된 section에서 option 값을 가져옵니다. vars가 제공되면, 딕셔너리이어야 합니다. option은 vars (제공되면), section 및 DEFAULTSECT 에서 순서대로 조회됩니다. 키를 찾을 수 없고 fallback이 제공되면, 대체 값으로 사용됩니다. None은 fallback 값으로 제공될 수 있습니다.

raw 인자가 참이 아닌 한, 모든 '%' 보간이 반환 값에서 확장됩니다. 보간 키의 값은 옵션과 같은 방식으로 조회됩니다.

버전 3.2에서 변경: 인자 raw, vars 및 fallback은 사용자가 세 번째 인자를 fallback 폴 백으로 사용하지 못하도록 하기 위해 키워드 전용입니다 (특히 매핑 프로토콜을 사용할 때).

getint(section, option, *, raw=False, vars=None[, fallback])

지정된 section의 option을 정수로 강제 변환하는 편의 메서드. raw, vars 및 fallback에 대한 설명은 get()을 참조하십시오.

getfloat(section, option, *, raw=False, vars=None[, fallback])

A convenience method which coerces the option in the specified section to a floating-point number. See get() for explanation of raw, vars and fallback.

getboolean(section, option, *, raw=False, vars=None[, fallback])

지정된 section의 option을 불리언 값으로 강제 변환하는 편의 메서드. 옵션에 허용되는 값은 이 메서드가 True를 반환하게 하는 '1', 'yes', 'true' 및 'on'과 False를 반환하게 하는 '0', 'no', 'false' 및 'off'입니다. 이 문자열 값은 대소 문자를 구분하지 않고 확인됩니다. 다른 모든 값은 ValueError를 발생시킵니다. raw, vars 및 fallback에 대한 설명은 get()을 참조하십시오.

items(raw=False, vars=None)

items(section, raw=False, vars=None)

section이 제공되지 않으면, DEFAULTSECT를 포함하여, section_name, section_proxy 쌍의 리스트를 반환합니다.

그렇지 않으면, 주어진 section의 옵션에 대해 name, value 쌍의 리스트를 반환합니다. 선택적 인자는 get() 메서드에서와 같은 의미입니다.

버전 3.8에서 변경: vars에 있는 항목은 더는 결과에 나타나지 않습니다. 이전 동작은 실제 구문 분석기 옵션과 보간을 위해 제공된 변수를 혼합했습니다.

set(section, option, value)

주어진 섹션이 존재하면, 주어진 옵션을 지정된 값으로 설정합니다; 그렇지 않으면 NoSectionError를 발생시킵니다. option과 value는 문자열이어야 합니다; 그렇지 않으면, TypeError가 발생합니다.

write(fileobject, space_around_delimiters=True)

텍스트 모드로 열렸어야 하는 (문자열을 받아들이는), 지정된 파일 객체에 구성의 표현을 기록합니다. 이 표현은 향후 read() 호출로 구문 분석할 수 있습니다. space_around_delimiters가 참이면, 키와 값 사이의 구분자는 공백으로 둘러싸입니다.

참고

Comments in the original configuration file are not preserved when writing the configuration back. What is considered a comment, depends on the given values for comment_prefix and inline_comment_prefix.

remove_option(section, option)

지정된 section에서 지정된 option을 제거합니다. 섹션이 존재하지 않으면, NoSectionError를 발생시킵니다. 제거되는 옵션이 존재했으면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

remove_section(section)

지정된 section을 구성에서 제거합니다. 실제로 섹션이 존재하면, True를 반환합니다. 그렇지 않으면 False를 반환합니다.

optionxform(option)

입력 파일에서 발견되거나 클라이언트 코드에서 전달된 옵션 이름 option을 내부 구조에서 사용되어야 하는 형식으로 변환합니다. 기본 구현은 option의 소문자 버전을 반환합니다; 이 동작에 영향을 주기 위해 서브 클래스가 이것을 재정의하거나 클라이언트 코드가 인스턴스에 이 이름의 어트리뷰트를 설정할 수 있습니다.

이 메서드를 사용하기 위해 구문 분석기를 서브 클래싱할 필요는 없으며, 문자열 인자를 취해서 문자열을 반환하는 함수로 인스턴스에 설정할 수도 있습니다. 예를 들어 str로 설정하면 옵션 이름이 대소 문자를 구분하게 됩니다:

cfgparser = ConfigParser()
cfgparser.optionxform = str

구성 파일을 읽을 때, optionxform()이 호출되기 전에 옵션 이름 주위의 공백이 제거됨에 유의하십시오.

configparser.UNNAMED_SECTION

A special object representing a section name used to reference the unnamed section (see Unnamed Sections).

configparser.MAX_INTERPOLATION_DEPTH

The maximum depth for recursive interpolation for get() when the raw parameter is false. This is relevant only when the default interpolation is used.

RawConfigParser 객체

class configparser.RawConfigParser(defaults=None, dict_type=dict, allow_no_value=False, *, delimiters=('=', ':'), comment_prefixes=('#', ';'), inline_comment_prefixes=None, strict=True, empty_lines_in_values=True, default_section=configparser.DEFAULTSECT, interpolation=BasicInterpolation(), converters={}, allow_unnamed_section=False)

ConfigParser의 레거시 변형. 기본적으로 보간이 비활성화되어 있으며 레거시 defaults= 키워드 인자 처리뿐만 아니라 안전하지 않은 add_section과 set 메서드를 통해 문자열이 아닌 섹션 이름, 옵션 이름 및 값을 허용합니다.

버전 3.2에서 변경: allow_no_value, delimiters, comment_prefixes, strict, empty_lines_in_values, default_section 및 interpolation이 추가되었습니다.

버전 3.5에서 변경: converters 인자가 추가되었습니다.

버전 3.8에서 변경: 이제 삽입 순서를 유지하므로, 기본 dict_type은 dict입니다.

버전 3.13에서 변경: The allow_unnamed_section argument was added.

참고

내부에 저장되는 값의 형을 검사하는 ConfigParser를 대신 사용하는 것을 고려하십시오. 보간을 원하지 않으면, ConfigParser(interpolation=None) 을 사용할 수 있습니다.

add_section(section)

Add a section named section or UNNAMED_SECTION to the instance.

If the given section already exists, DuplicateSectionError is raised. If the default section name is passed, ValueError is raised. If UNNAMED_SECTION is passed and support is disabled, UnnamedSectionDisabledError is raised.

section의 형을 검사하지 않아서 사용자가 문자열이 아닌 섹션을 만들 수 있도록 합니다. 이 동작은 지원되지 않으며 내부 에러를 일으킬 수 있습니다.

버전 3.14에서 변경: Added support for UNNAMED_SECTION.

set(section, option, value)

주어진 섹션이 존재하면, 주어진 옵션을 지정된 값으로 설정합니다; 그렇지 않으면 NoSectionError를 발생시킵니다. 문자열이 아닌 값을 내부에 저장하도록 RawConfigParser(또는 raw 매개 변수가 참으로 설정된 ConfigParser)를 사용할 수 있지만, 전체 기능(보간과 파일로의 출력을 포함하는)은 문자열 값으로만 수행할 수 있습니다.

이 메서드를 사용하면 문자열이 아닌 값을 키에 내부적으로 대입할 수 있습니다. 이 동작은 지원되지 않으며 파일에 쓰려고 하거나 비 원시 모드에서 가져오려고 할 때 에러가 발생합니다. 이러한 대입을 허용하지 않는 매핑 프로토콜 API를 사용하십시오.

예외

exception configparser.Error

다른 모든 configparser 예외의 베이스 클래스.

exception configparser.NoSectionError

지정된 섹션을 찾지 못할 때 발생하는 예외.

exception configparser.DuplicateSectionError

Exception raised if add_section() is called with the name of a section that is already present or in strict parsers when a section if found more than once in a single input file, string or dictionary.

버전 3.2에서 변경: Added the optional source and lineno attributes and parameters to __init__().

exception configparser.DuplicateOptionError

단일 파일, 문자열 또는 딕셔너리에서 읽는 동안 단일 옵션이 두 번 나타날 때 엄격한(strict) 구문 분석기가 발생시키는 예외. 이는 맞춤법과 대소 문자 구분과 관련된 에러를 잡습니다, 예를 들어 딕셔너리에는 대소 문자를 구분하지 않는 같은 구성 키를 나타내는 두 개의 키가 있을 수 있습니다.

exception configparser.NoOptionError

지정된 섹션에서 지정된 옵션을 찾지 못할 때 발생하는 예외.

exception configparser.InterpolationError

문자열 보간 수행 시 문제가 발생할 때 발생하는 예외의 베이스 클래스.

exception configparser.InterpolationDepthError

이터레이션 횟수가 MAX_INTERPOLATION_DEPTH를 초과하여 문자열 보간을 완료할 수 없을 때 발생하는 예외. InterpolationError의 서브 클래스.

exception configparser.InterpolationMissingOptionError

값에서 참조된 옵션이 존재하지 않을 때 발생하는 예외. InterpolationError의 서브 클래스.

exception configparser.InterpolationSyntaxError

치환이 이루어질 소스 텍스트가 요구되는 문법을 준수하지 않을 때 발생하는 예외. InterpolationError의 서브 클래스.

exception configparser.MissingSectionHeaderError

섹션 헤더가 없는 파일을 구문 분석하려고 할 때 발생하는 예외.

exception configparser.ParsingError

파일 구문 분석 중에 에러가 발생할 때 발생하는 예외.

버전 3.12에서 변경: The filename attribute and __init__() constructor argument were removed. They have been available using the name source since 3.2.

exception configparser.MultilineContinuationError

Exception raised when a key without a corresponding value is continued with an indented line.

Added in version 3.13.

exception configparser.UnnamedSectionDisabledError

Exception raised when attempting to use the UNNAMED_SECTION without enabling it.

Added in version 3.14.

각주

[1] (1,2,3,4,5,6,7,8,9,10,11)

구성 구문 분석기는 심도 있는 사용자 정의를 허용합니다. 각주 참조로 요약된 동작을 변경하는 데 관심이 있으면 구문 분석기 동작 사용자 정의 섹션을 참조하십시오.

tomllib — Parse TOML files

Added in version 3.11.

Source code: Lib/tomllib [https://github.com/python/cpython/tree/main/Lib/tomllib]

This module provides an interface for parsing TOML 1.0.0 (Tom’s Obvious Minimal Language, https://toml.io [https://toml.io/en/]). This module does not support writing TOML.

더 보기

The Tomli-W package [https://pypi.org/project/tomli-w/] is a TOML writer that can be used in conjunction with this module, providing a write API familiar to users of the standard library marshal and pickle modules.

더 보기

The TOML Kit package [https://pypi.org/project/tomlkit/] is a style-preserving TOML library with both read and write capability. It is a recommended replacement for this module for editing already existing TOML files.

This module defines the following functions:

tomllib.load(fp, /, *, parse_float=float)

Read a TOML file. The first argument should be a readable and binary file object. Return a dict. Convert TOML types to Python using this conversion table.

parse_float will be called with the string of every TOML float to be decoded. By default, this is equivalent to float(num_str). This can be used to use another datatype or parser for TOML floats (e.g. decimal.Decimal). The callable must not return a dict or a list, else a ValueError is raised.

A TOMLDecodeError will be raised on an invalid TOML document.

tomllib.loads(s, /, *, parse_float=float)

Load TOML from a str object. Return a dict. Convert TOML types to Python using this conversion table. The parse_float argument has the same meaning as in load().

A TOMLDecodeError will be raised on an invalid TOML document.

The following exceptions are available:

exception tomllib.TOMLDecodeError(msg, doc, pos)

Subclass of ValueError with the following additional attributes:

msg

The unformatted error message.

doc

The TOML document being parsed.

pos

The index of doc where parsing failed.

lineno

The line corresponding to pos.

colno

The column corresponding to pos.

버전 3.14에서 변경: Added the msg, doc and pos parameters. Added the msg, doc, pos, lineno and colno attributes.

버전 3.14부터 폐지됨: Passing free-form positional arguments is deprecated.

Examples

Parsing a TOML file:

import tomllib

with open("pyproject.toml", "rb") as f:
    data = tomllib.load(f)

Parsing a TOML string:

import tomllib

toml_str = """
python-version = "3.11.0"
python-implementation = "CPython"
"""

data = tomllib.loads(toml_str)

Conversion Table

TOML

Python

TOML document

dict

string

str

integer

int

float

float (configurable with parse_float)

boolean

bool

offset date-time

datetime.datetime (tzinfo attribute set to an instance of datetime.timezone)

local date-time

datetime.datetime (tzinfo attribute set to None)

local date

datetime.date

local time

datetime.time

array

list

table

dict

inline table

dict

array of tables

list of dicts

netrc — netrc file processing

소스 코드: Lib/netrc.py [https://github.com/python/cpython/tree/main/Lib/netrc.py]

netrc 클래스는 유닉스 ftp 프로그램과 다른 FTP 클라이언트가 사용하는 netrc 파일 형식을 구문 분석하고 캡슐화합니다.

class netrc.netrc([file])

netrc 인스턴스나 서브 클래스 인스턴스는 netrc 파일의 데이터를 캡슐화합니다. 초기화 인자가 있으면 구문 분석할 파일을 지정합니다. 인자를 지정하지 않으면, os.path.expanduser()에 의해 결정된 사용자 홈 디렉터리에 있는 파일 .netrc를 읽습니다. 그렇지 않으면, FileNotFoundError 예외가 발생합니다. 구문 분석 에러는 파일 이름, 줄 번호 및 종료 토큰을 포함하는 진단 정보로 NetrcParseError를 발생시킵니다. POSIX 시스템에서 인자가 지정되지 않을 때, 파일 소유권이나 권한이 안전하지 않으면 (프로세스를 실행하는 사용자가 아닌 다른 사용자가 소유하거나 다른 모든 사용자가 읽기 또는 쓰기로 액세스할 수 있는 경우), .netrc 파일에 암호가 존재하면 NetrcParseError가 발생합니다. 이것은 ftp와 .netrc를 사용하는 다른 프로그램과 동등한 보안 행동을 구현합니다.

버전 3.4에서 변경: POSIX 권한 검사를 추가했습니다.

버전 3.7에서 변경: file이 인자로 전달되지 않으면 os.path.expanduser()가 .netrc 파일의 위치를 찾는 데 사용됩니다.

버전 3.10에서 변경: netrc try UTF-8 encoding before using locale specific encoding. The entry in the netrc file no longer needs to contain all tokens. The missing tokens’ value default to an empty string. All the tokens and their values now can contain arbitrary characters, like whitespace and non-ASCII characters. If the login name is anonymous, it won’t trigger the security check.

exception netrc.NetrcParseError

Exception raised by the netrc class when syntactical errors are encountered in source text. Instances of this exception provide three interesting attributes:

msg

Textual explanation of the error.

filename

The name of the source file.

lineno

The line number on which the error was found.

netrc 객체

netrc 인스턴스에는 다음과 같은 메서드가 있습니다:

netrc.authenticators(host)

host에 대한 인증 자의 3-tuple (login, account, password)를 반환합니다. netrc 파일에 주어진 호스트에 대한 항목이 없으면 ‘default’ 항목과 연관된 튜플을 반환합니다. 일치하는 호스트도 기본 항목도 사용할 수 없으면 None을 반환합니다.

netrc.__repr__()

클래스 데이터를 netrc 파일의 형식의 문자열로 덤프합니다. (이것은 주석을 버리고 엔트리를 재정렬할 수 있습니다.)

netrc의 인스턴스에는 공개 인스턴스 변수가 있습니다:

netrc.hosts

호스트 이름을 (login, account, password) 튜플에 매핑하는 딕셔너리. ‘default’ 항목이 있으면 그 이름의 의사 호스트로 표시됩니다.

netrc.macros

매크로 이름을 문자열 리스트에 매핑하는 딕셔너리.

plistlib — Generate and parse Apple .plist files

소스 코드: Lib/plistlib.py [https://github.com/python/cpython/tree/main/Lib/plistlib.py]

이 모듈은 애플, 주로 macOS와 iOS에서 사용되는 “프로퍼티 리스트(property list)” 파일을 읽고 쓰는 인터페이스를 제공합니다. 이 모듈은 바이너리와 XML plist 파일을 모두 지원합니다.

프로퍼티 리스트 (.plist) 파일 형식은 딕셔너리, 리스트, 숫자 및 문자열과 같은 기본 객체 형을 지원하는 간단한 직렬화입니다. 일반적으로 최상위 객체는 딕셔너리입니다.

plist 파일을 쓰고 구문 분석하려면, dump()와 load() 함수를 사용하십시오.

To work with plist data in bytes or string objects, use dumps() and loads().

값은 문자열, 정수, 부동 소수점, 논릿값, 튜플, 리스트, 딕셔너리 (단, 문자열 키만 가능), bytes, bytearray 또는 datetime.datetime 객체일 수 있습니다.

버전 3.4에서 변경: 새 API, 이전 API는 폐지되었습니다. 바이너리 형식 plist에 대한 지원이 추가되었습니다.

버전 3.8에서 변경: NSKeyedArchiver 와 NSKeyedUnarchiver 에서 사용되듯이 바이너리 plist에서 UID 토큰을 읽고 쓰는 것에 대한 지원이 추가되었습니다.

버전 3.9에서 변경: 낡은 API가 제거되었습니다.

더 보기

PList manual page [https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/PropertyLists/]

애플의 파일 형식 설명서.

이 모듈은 다음 함수를 정의합니다:

plistlib.load(fp, *, fmt=None, dict_type=dict, aware_datetime=False)

plist 파일을 읽습니다. fp는 읽을 수 있는 바이너리 파일 객체여야 합니다. 해독된 루트 객체를 반환합니다 (일반적으로 딕셔너리입니다).

fmt는 파일의 형식이며 다음 값이 유효합니다:

None: 파일 형식을 자동 감지

FMT_XML: XML 파일 형식

FMT_BINARY: 바이너리 plist 형식

dict_type은 plist 파일에서 읽은 딕셔너리에 사용되는 형입니다.

When aware_datetime is true, fields with type datetime.datetime will be created as aware object, with tzinfo as datetime.UTC.

FMT_XML 형식의 XML 데이터는 xml.parsers.expat 의 Expat 구문 분석기로 구문 분석됩니다 – 잘못된 형식의 XML로 인한 예외에 대해서는 해당 설명서를 참조하십시오. 알 수 없는 엘리먼트는 plist 구문분석기에서 단순히 무시됩니다.

바이너리 형식의 구문 분석기는 파일을 구문 분석할 수 없을 때 InvalidFileException를 발생시킵니다.

Added in version 3.4.

버전 3.13에서 변경: The keyword-only parameter aware_datetime has been added.

plistlib.loads(data, *, fmt=None, dict_type=dict, aware_datetime=False)

Load a plist from a bytes or string object. See load() for an explanation of the keyword arguments.

Added in version 3.4.

버전 3.13에서 변경: data can be a string when fmt equals FMT_XML.

plistlib.dump(value, fp, *, fmt=FMT_XML, sort_keys=True, skipkeys=False, aware_datetime=False)

plist 파일에 value를 씁니다. Fp는 쓰기 가능한 바이너리 파일 객체여야 합니다.

fmt 인자는 plist 파일의 형식을 지정하며 다음 값 중 하나일 수 있습니다:

FMT_XML: XML 형식의 plist 파일

FMT_BINARY: 바이너리 형식의 plist 파일

sort_keys가 참(기본값)이면 딕셔너리의 키가 정렬된 순서로 plist에 기록되고, 그렇지 않으면 딕셔너리의 이터레이션 순서로 기록됩니다.

skipkeys가 거짓(기본값)일 때, 딕셔너리의 키가 문자열이 아니면 함수는 TypeError를 발생시킵니다. 그렇지 않으면 해당 키를 건너뜁니다.

When aware_datetime is true and any field with type datetime.datetime is set as an aware object, it will convert to UTC timezone before writing it.

객체가 지원되지 않는 형이거나 지원되지 않는 형의 객체를 포함하는 컨테이너면 TypeError가 발생합니다.

(바이너리) plist 파일에서 표현할 수 없는 정숫값은 OverflowError를 발생시킵니다.

Added in version 3.4.

버전 3.13에서 변경: The keyword-only parameter aware_datetime has been added.

plistlib.dumps(value, *, fmt=FMT_XML, sort_keys=True, skipkeys=False, aware_datetime=False)

plist 형식의 바이트열 객체로 value를 반환합니다. 이 함수의 키워드 인자에 대한 설명은 dump() 설명서를 참조하십시오.

Added in version 3.4.

다음 클래스를 사용할 수 있습니다:

class plistlib.UID(data)

int를 감쌉니다. 이것은 UID를 포함하는 NSKeyedArchiver 인코딩된 데이터를 읽거나 쓸 때 사용됩니다 (PList 매뉴얼을 참조하십시오).

It has one attribute, data, which can be used to retrieve the int value of the UID. data must be in the range 0 <= data < 2**64.

Added in version 3.8.

다음 상수를 사용할 수 있습니다:

plistlib.FMT_XML

plist 파일의 XML 형식.

Added in version 3.4.

plistlib.FMT_BINARY

plist 파일의 바이너리 형식

Added in version 3.4.

예제

plist 만들기:

import datetime
import plistlib

pl = dict(
    aString = "Doodah",
    aList = ["A", "B", 12, 32.1, [1, 2, 3]],
    aFloat = 0.1,
    anInt = 728,
    aDict = dict(
        anotherString = "<hello & hi there!>",
        aThirdString = "M\xe4ssig, Ma\xdf",
        aTrueValue = True,
        aFalseValue = False,
    ),
    someData = b"<binary gunk>",
    someMoreData = b"<lots of binary gunk>" * 10,
    aDate = datetime.datetime.now()
)
print(plistlib.dumps(pl).decode())

plist 구문 분석하기:

import plistlib

plist = b"""<plist version="1.0">
<dict>
    <key>foo</key>
    <string>bar</string>
</dict>
</plist>"""
pl = plistlib.loads(plist)
print(pl["foo"])

암호화 서비스

The modules described in this chapter implement various algorithms of a cryptographic nature. They are available at the discretion of the installation. Here’s an overview:

hashlib — Secure hashes and message digests

해시 알고리즘

Usage

Constructors

new()

md5()

sha1()

sha224()

sha256()

sha384()

sha512()

sha3_224()

sha3_256()

sha3_384()

sha3_512()

Attributes

algorithms_guaranteed

algorithms_available

Hash Objects

digest_size

block_size

name

update()

digest()

hexdigest()

copy()

SHAKE 가변 길이 요약

shake_128()

shake_256()

digest()

hexdigest()

File hashing

file_digest()

키 파생

pbkdf2_hmac()

scrypt()

BLAKE2

해시 객체 만들기

blake2b()

blake2s()

상수

SALT_SIZE

SALT_SIZE

PERSON_SIZE

PERSON_SIZE

MAX_KEY_SIZE

MAX_KEY_SIZE

MAX_DIGEST_SIZE

MAX_DIGEST_SIZE

예

간단한 해싱

다른 요약 크기 사용하기

키 해싱

무작위 해싱

개인화

트리 모드

크레딧

hmac — Keyed-Hashing for Message Authentication

new()

digest()

update()

digest()

hexdigest()

copy()

digest_size

block_size

name

compare_digest()

secrets — Generate secure random numbers for managing secrets

난수

SystemRandom

choice()

randbelow()

randbits()

토큰 생성

token_bytes()

token_hex()

token_urlsafe()

토큰은 몇 바이트를 사용해야 합니까?

기타 함수

compare_digest()

조리법과 모범 사례

hashlib — Secure hashes and message digests

소스 코드: Lib/hashlib.py [https://github.com/python/cpython/tree/main/Lib/hashlib.py]

This module implements a common interface to many different secure hash and message digest algorithms. Included are the FIPS secure hash algorithms SHA1, SHA224, SHA256, SHA384, SHA512, (defined in the FIPS 180-4 standard [https://csrc.nist.gov/pubs/fips/180-4/upd1/final]), the SHA-3 series (defined in the FIPS 202 standard [https://csrc.nist.gov/pubs/fips/202/final]) as well as RSA’s MD5 algorithm (defined in internet RFC 1321 [https://datatracker.ietf.org/doc/html/rfc1321.html]). The terms “secure hash” and “message digest” are interchangeable. Older algorithms were called message digests. The modern term is secure hash.

참고

adler32나 crc32 해시 함수를 원한다면, zlib 모듈에 있습니다.

해시 알고리즘

There is one constructor method named for each type of hash. All return a hash object with the same simple interface. For example: use sha256() to create a SHA-256 hash object. You can now feed this object with bytes-like objects (normally bytes) using the update method. At any point you can ask it for the digest of the concatenation of the data fed to it so far using the digest() or hexdigest() methods.

To allow multithreading, the Python GIL is released while computing a hash supplied more than 2047 bytes of data at once in its constructor or .update method.

Constructors for hash algorithms that are always present in this module are sha1(), sha224(), sha256(), sha384(), sha512(), sha3_224(), sha3_256(), sha3_384(), sha3_512(), shake_128(), shake_256(), blake2b(), and blake2s(). md5() is normally available as well, though it may be missing or blocked if you are using a rare “FIPS compliant” build of Python. These correspond to algorithms_guaranteed.

Additional algorithms may also be available if your Python distribution’s hashlib was linked against a build of OpenSSL that provides others. Others are not guaranteed available on all installations and will only be accessible by name via new(). See algorithms_available.

경고

Some algorithms have known hash collision weaknesses (including MD5 and SHA1). Refer to Attacks on cryptographic hash algorithms [https://en.wikipedia.org/wiki/Cryptographic_hash_function#Attacks_on_cryptographic_hash_algorithms] and the hashlib-seealso section at the end of this document.

Added in version 3.6: SHA3 (Keccak) and SHAKE constructors sha3_224(), sha3_256(), sha3_384(), sha3_512(), shake_128(), shake_256() were added. blake2b() and blake2s() were added.

버전 3.9에서 변경: 모든 hashlib 생성자는 기본값이 True인 키워드 전용 인자 usedforsecurity를 취합니다. 값이 거짓이면 제한된 환경에서 안전하지 않고 차단된 해싱 알고리즘 사용을 허락합니다. False는 해싱 알고리즘이 보안 문맥에서 사용되지 않음을 나타냅니다, 예를 들어 암호화가 아닌 단방향 압축 함수로.

버전 3.9에서 변경: Hashlib now uses SHA3 and SHAKE from OpenSSL if it provides it.

버전 3.12에서 변경: For any of the MD5, SHA1, SHA2, or SHA3 algorithms that the linked OpenSSL does not provide we fall back to a verified implementation from the HACL* project [https://github.com/hacl-star/hacl-star].

Usage

To obtain the digest of the byte string b"Nobody inspects the spammish repetition":

>>> import hashlib
>>> m = hashlib.sha256()
>>> m.update(b"Nobody inspects")
>>> m.update(b" the spammish repetition")
>>> m.digest()
b'\x03\x1e\xdd}Ae\x15\x93\xc5\xfe\\\x00o\xa5u+7\xfd\xdf\xf7\xbcN\x84:\xa6\xaf\x0c\x95\x0fK\x94\x06'
>>> m.hexdigest()
'031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'

더 압축하면:

>>> hashlib.sha256(b"Nobody inspects the spammish repetition").hexdigest()
'031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'

Constructors

hashlib.new(name, [data, ]*, usedforsecurity=True)

Is a generic constructor that takes the string name of the desired algorithm as its first parameter. It also exists to allow access to the above listed hashes as well as any other algorithms that your OpenSSL library may offer.

Using new() with an algorithm name:

>>> h = hashlib.new('sha256')
>>> h.update(b"Nobody inspects the spammish repetition")
>>> h.hexdigest()
'031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'

hashlib.md5([data, ]*, usedforsecurity=True)

hashlib.sha1([data, ]*, usedforsecurity=True)

hashlib.sha224([data, ]*, usedforsecurity=True)

hashlib.sha256([data, ]*, usedforsecurity=True)

hashlib.sha384([data, ]*, usedforsecurity=True)

hashlib.sha512([data, ]*, usedforsecurity=True)

hashlib.sha3_224([data, ]*, usedforsecurity=True)

hashlib.sha3_256([data, ]*, usedforsecurity=True)

hashlib.sha3_384([data, ]*, usedforsecurity=True)

hashlib.sha3_512([data, ]*, usedforsecurity=True)

Named constructors such as these are faster than passing an algorithm name to new().

Attributes

Hashlib provides the following constant module attributes:

hashlib.algorithms_guaranteed

모든 플랫폼에서 이 모듈이 지원하도록 보장된 해시 알고리즘의 이름을 포함하는 집합. ‘md5’는 일부 업스트림 공급자가 이를 제외하는 이상한 “FIPS 호환” 파이썬 빌드를 제공하지만, 이 목록에 있음에 유의하십시오.

Added in version 3.2.

hashlib.algorithms_available

실행 중인 파이썬 인터프리터에서 사용 가능한 해시 알고리즘의 이름이 포함된 집합. 이 이름들은 new()에 전달될 때 인식됩니다. algorithms_guaranteed는 항상 부분 집합입니다. 이 집합에서 같은 알고리즘이 다른 이름으로 여러 번 나타날 수 있습니다 (OpenSSL 덕분입니다).

Added in version 3.2.

Hash Objects

다음 값은 생성자가 반환한 해시 객체의 상수 어트리뷰트로 제공됩니다:

hash.digest_size

결과 해시의 바이트 단위의 크기.

hash.block_size

해시 알고리즘의 바이트 단위의 내부 블록 크기.

해시 객체에는 다음과 같은 어트리뷰트가 있습니다:

hash.name

이 해시의 규범적 이름, 항상 소문자이며 항상 이 유형의 다른 해시를 만들기 위한 new()에 대한 매개 변수로 적합합니다.

버전 3.4에서 변경: name 어트리뷰트는 처음부터 CPython에 존재했지만, 파이썬 3.4 이전에는 공식적으로 지정되지 않아서, 일부 플랫폼에는 존재하지 않을 수 있습니다.

해시 객체에는 다음과 같은 메서드가 있습니다:

hash.update(data)

바이트열류 객체로 해시 객체를 갱신합니다. 반복되는 호출은 모든 인자를 이어붙인 단일 호출과 동등합니다: m.update(a); m.update(b)는 m.update(a+b)와 동등합니다.

hash.digest()

지금까지 update() 메서드에 전달된 데이터의 요약을 반환합니다. 이것은 digest_size 크기의 바이트열 객체이며 0에서 255까지의 전체 범위에 있는 바이트를 포함할 수 있습니다.

hash.hexdigest()

digest()와 유사하지만, 요약은 16진수 숫자만 포함하는 두 배 길이의 문자열 객체로 반환됩니다. 전자 메일이나 기타 바이너리가 아닌 환경에서 값을 안전하게 교환하는 데 사용할 수 있습니다.

hash.copy()

해시 객체의 사본(“복제본”)을 반환합니다. 이것은 공통된 초기 부분 문자열을 공유하는 데이터의 요약을 효율적으로 계산하는 데 사용될 수 있습니다.

SHAKE 가변 길이 요약

hashlib.shake_128([data, ]*, usedforsecurity=True)

hashlib.shake_256([data, ]*, usedforsecurity=True)

shake_128()과 shake_256() 알고리즘은 length_in_bits//2 (최대 128이나 256) 비트의 보안성으로 가변 길이 요약을 제공합니다. 따라서 digest 메서드에는 길이(length)가 필요합니다. 최대 길이는 SHAKE 알고리즘에 의해 제한되지 않습니다.

shake.digest(length)

Return the digest of the data passed to the update() method so far. This is a bytes object of size length which may contain bytes in the whole range from 0 to 255.

shake.hexdigest(length)

Like digest() except the digest is returned as a string object of double length, containing only hexadecimal digits. This may be used to exchange the value in email or other non-binary environments.

Example use:

>>> h = hashlib.shake_256(b'Nobody inspects the spammish repetition')
>>> h.hexdigest(20)
'44709d6fcb83d92a76dcb0b668c98e1b1d3dafe7'

File hashing

The hashlib module provides a helper function for efficient hashing of a file or file-like object.

hashlib.file_digest(fileobj, digest, /)

Return a digest object that has been updated with contents of file object.

fileobj must be a file-like object opened for reading in binary mode. It accepts file objects from builtin open(), BytesIO instances, SocketIO objects from socket.socket.makefile(), and similar. The function may bypass Python’s I/O and use the file descriptor from fileno() directly. fileobj must be assumed to be in an unknown state after this function returns or raises. It is up to the caller to close fileobj.

digest must either be a hash algorithm name as a str, a hash constructor, or a callable that returns a hash object.

Example:

>>> import io, hashlib, hmac
>>> with open(hashlib.__file__, "rb") as f:
...     digest = hashlib.file_digest(f, "sha256")
...
>>> digest.hexdigest()
'...'

>>> buf = io.BytesIO(b"somedata")
>>> mac1 = hmac.HMAC(b"key", digestmod=hashlib.sha512)
>>> digest = hashlib.file_digest(buf, lambda: mac1)

>>> digest is mac1
True
>>> mac2 = hmac.HMAC(b"key", b"somedata", digestmod=hashlib.sha512)
>>> mac1.digest() == mac2.digest()
True

Added in version 3.11.

키 파생

키 파생(key derivation)과 키 확장(key stretching) 알고리즘은 안전한 암호 해싱을 위해 설계되었습니다. sha1(password)와 같은 순진한 알고리즘은 무차별 대입 공격에 내성이 없습니다. 올바른 암호 해싱 함수는 조정할 수 있고, 느리고, 솔트(salt) [https://en.wikipedia.org/wiki/Salt_%28cryptography%29]를 포함해야 합니다.

hashlib.pbkdf2_hmac(hash_name, password, salt, iterations, dklen=None)

이 함수는 PKCS#5 암호 기반 키 파생 함수 2를 제공합니다. 의사 난수 함수로 HMAC을 사용합니다.

문자열 hash_name은 원하는 HMAC을 위한 해시 요약 알고리즘의 이름입니다, 예를 들어 ‘sha1’이나 ‘sha256’. password와 salt는 바이트 버퍼로 해석됩니다. 응용 프로그램과 라이브러리는 password를 적당한 길이(예를 들어 1024)로 제한해야 합니다. salt는 적절한 소스(예를 들어 os.urandom())로부터 온 약 16이나 그 이상의 바이트여야 합니다.

The number of iterations should be chosen based on the hash algorithm and computing power. As of 2022, hundreds of thousands of iterations of SHA-256 are suggested. For rationale as to why and how to choose what is best for your application, read Appendix A.2.2 of NIST-SP-800-132 [https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf]. The answers on the stackexchange pbkdf2 iterations question [https://security.stackexchange.com/questions/3959/recommended-of-iterations-when-using-pbkdf2-sha256/] explain in detail.

dklen is the length of the derived key in bytes. If dklen is None then the digest size of the hash algorithm hash_name is used, e.g. 64 for SHA-512.

>>> from hashlib import pbkdf2_hmac
>>> our_app_iters = 500_000  # Application specific, read above.
>>> dk = pbkdf2_hmac('sha256', b'password', b'bad salt' * 2, our_app_iters)
>>> dk.hex()
'15530bba69924174860db778f2c6f8104d3aaf9d26241840c8c4a641c8d000a9'

Function only available when Python is compiled with OpenSSL.

Added in version 3.4.

버전 3.12에서 변경: Function now only available when Python is built with OpenSSL. The slow pure Python implementation has been removed.

hashlib.scrypt(password, *, salt, n, r, p, maxmem=0, dklen=64)

이 함수는 RFC 7914 [https://datatracker.ietf.org/doc/html/rfc7914.html]에 정의된 대로 scrypt 암호 기반 키 파생 함수를 제공합니다.

password와 salt는 바이트열류 객체여야 합니다. 응용 프로그램과 라이브러리는 password를 적당한 길이(예를 들어 1024)로 제한해야 합니다. salt는 적절한 소스(예를 들어 os.urandom())로부터 온 약 16이나 그 이상의 바이트여야 합니다.

n is the CPU/Memory cost factor, r the block size, p parallelization factor and maxmem limits memory (OpenSSL 1.1.0 defaults to 32 MiB). dklen is the length of the derived key in bytes.

Added in version 3.6.

BLAKE2

BLAKE2 [https://www.blake2.net]는 RFC 7693 [https://datatracker.ietf.org/doc/html/rfc7693.html]에 정의된 암호화 해시 함수로, 두 가지 방식으로 제공됩니다:

BLAKE2b, 64비트 플랫폼에 최적화되어 있으며 1에서 64바이트 사이의 모든 크기의 요약을 생성합니다,

BLAKE2s, 8비트에서 32비트 플랫폼에 최적화되어 있으며 1에서 32바이트 사이의 모든 크기의 요약을 생성합니다.

BLAKE2는 키 모드(keyed mode) (HMAC [https://en.wikipedia.org/wiki/Hash-based_message_authentication_code]의 더 빠르고 간단한 대체), 솔트 해싱(salted hashing), 개인화(personalization) 및 트리 해싱(tree hashing)을 지원합니다.

이 모듈의 해시 객체는 표준 라이브러리의 hashlib 객체의 API를 따릅니다.

해시 객체 만들기

생성자 함수를 호출하여 새 해시 객체를 만듭니다:

hashlib.blake2b(data=b'', *, digest_size=64, key=b'', salt=b'', person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, node_depth=0, inner_size=0, last_node=False, usedforsecurity=True)

hashlib.blake2s(data=b'', *, digest_size=32, key=b'', salt=b'', person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, node_depth=0, inner_size=0, last_node=False, usedforsecurity=True)

이 함수는 BLAKE2b나 BLAKE2s를 계산하기위한 해당 해시 객체를 반환합니다. 선택적으로 다음과 같은 일반 매개 변수를 취합니다:

data: 해시 할 초기 데이터 청크, 바이트열류 객체여야 합니다. 위치 인자로만 전달될 수 있습니다.

digest_size: 바이트 단위의 출력 요약 크기.

key: 키 해싱을 위한 키 (BLAKE2b의 경우 최대 64바이트, BLAKE2s의 경우 최대 32바이트).

salt: 무작위 해싱을 위한 솔트 (BLAKE2b의 경우 최대 16바이트, BLAKE2s의 경우 최대 8바이트).

person: 개인화 문자열 (BLAKE2b의 경우 최대 16바이트, BLAKE2s의 경우 최대 8바이트).

다음 표는 일반 매개 변수의 제한(바이트 단위)을 보여줍니다:

해시

digest_size

len(key)

len(salt)

len(person)

BLAKE2b

64

64

16

16

BLAKE2s

32

32

8

8

참고

BLAKE2 명세는 솔트와 개인화 매개 변수에 대해 상수 길이를 정의하지만, 편의상, 이 구현에서는 지정된 길이까지 모든 크기의 바이트 문자열을 받아들입니다. 매개 변수의 길이가 지정된 길이보다 작으면, 0으로 채워지므로, 예를 들어 b'salt'와 b'salt\x00'은 같은 값입니다. (key의 경우에는 해당하지 않습니다.)

이 크기는 아래 설명된 모듈 상수로 제공됩니다.

생성자 함수는 다음 트리 해싱 매개 변수도 받아들입니다:

fanout: 팬아웃 (0에서 255, 무제한이면 0, 순차적 모드(sequential mode)이면 1).

depth: 트리의 최대 깊이 (1에서 255, 무제한이면 255, 순차적 모드이면 1).

leaf_size: maximal byte length of leaf (0 to 2**32-1, 0 if unlimited or in sequential mode).

node_offset: node offset (0 to 2**64-1 for BLAKE2b, 0 to 2**48-1 for BLAKE2s, 0 for the first, leftmost, leaf, or in sequential mode).

node_depth: 노드 깊이 (0에서 255, 리프나 순차적 모드이면 0).

inner_size: 내부 요약 크기 (BLAKE2b의 경우 0에서 64, BLAKE2s의 경우 0에서 32, 순차적 모드이면 0).

last_node: boolean indicating whether the processed node is the last one (False for sequential mode).

See section 2.10 in BLAKE2 specification [https://www.blake2.net/blake2_20130129.pdf] for comprehensive review of tree hashing.

상수

blake2b.SALT_SIZE

blake2s.SALT_SIZE

솔트 길이 (생성자가 허용하는 최대 길이).

blake2b.PERSON_SIZE

blake2s.PERSON_SIZE

개인화 문자열 길이 (생성자가 허용하는 최대 길이).

blake2b.MAX_KEY_SIZE

blake2s.MAX_KEY_SIZE

최대 키 크기.

blake2b.MAX_DIGEST_SIZE

blake2s.MAX_DIGEST_SIZE

해시 함수가 출력할 수 있는 최대 요약 크기.

예

간단한 해싱

To calculate hash of some data, you should first construct a hash object by calling the appropriate constructor function (blake2b() or blake2s()), then update it with the data by calling update() on the object, and, finally, get the digest out of the object by calling digest() (or hexdigest() for hex-encoded string).

>>> from hashlib import blake2b
>>> h = blake2b()
>>> h.update(b'Hello world')
>>> h.hexdigest()
'6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'

줄여서, 첫 번째 데이터 청크를 위치 인자로 생성자에 전달하여 직접 갱신할 수 있습니다:

>>> from hashlib import blake2b
>>> blake2b(b'Hello world').hexdigest()
'6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'

해시를 반복적으로 갱신하는 데 필요한 만큼 hash.update()를 호출할 수 있습니다:

>>> from hashlib import blake2b
>>> items = [b'Hello', b' ', b'world']
>>> h = blake2b()
>>> for item in items:
...     h.update(item)
...
>>> h.hexdigest()
'6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'

다른 요약 크기 사용하기

BLAKE2는 BLAKE2b의 경우 최대 64바이트, BLAKE2s의 경우 최대 32바이트까지 요약 크기를 구성할 수 있습니다. 예를 들어, 출력 크기를 변경하지 않고 SHA-1을 BLAKE2b로 바꾸려면, BLAKE2b에 20바이트 요약을 생성하도록 지시할 수 있습니다:

>>> from hashlib import blake2b
>>> h = blake2b(digest_size=20)
>>> h.update(b'Replacing SHA1 with the more secure function')
>>> h.hexdigest()
'd24f26cf8de66472d58d4e1b1774b4c9158b1f4c'
>>> h.digest_size
20
>>> len(h.digest())
20

요약 크기가 다른 해시 객체의 출력은 완전히 다릅니다 (짧은 해시는 긴 해시의 접두사가 아닙니다); BLAKE2b와 BLAKE2s는 출력 길이가 같더라도 다른 출력을 생성합니다:

>>> from hashlib import blake2b, blake2s
>>> blake2b(digest_size=10).hexdigest()
'6fa1d8fcfd719046d762'
>>> blake2b(digest_size=11).hexdigest()
'eb6ec15daf9546254f0809'
>>> blake2s(digest_size=10).hexdigest()
'1bf21a98c78a1c376ae9'
>>> blake2s(digest_size=11).hexdigest()
'567004bf96e4a25773ebf4'

키 해싱

Keyed hashing can be used for authentication as a faster and simpler replacement for Hash-based message authentication code [https://en.wikipedia.org/wiki/HMAC] (HMAC). BLAKE2 can be securely used in prefix-MAC mode thanks to the indifferentiability property inherited from BLAKE.

이 예는 키 b'pseudorandom key'로 메시지 b'message data'에 대한 (16진 인코딩된) 128비트 인증 코드를 얻는 방법을 보여줍니다:

>>> from hashlib import blake2b
>>> h = blake2b(key=b'pseudorandom key', digest_size=16)
>>> h.update(b'message data')
>>> h.hexdigest()
'3d363ff7401e02026f4a4687d4863ced'

실용적인 예로, 웹 응용 프로그램은 사용자에게 전송된 쿠키에 대칭적으로 서명한 후 나중에 변조되지 않았는지 확인할 수 있습니다:

>>> from hashlib import blake2b
>>> from hmac import compare_digest
>>>
>>> SECRET_KEY = b'pseudorandomly generated server secret key'
>>> AUTH_SIZE = 16
>>>
>>> def sign(cookie):
...     h = blake2b(digest_size=AUTH_SIZE, key=SECRET_KEY)
...     h.update(cookie)
...     return h.hexdigest().encode('utf-8')
>>>
>>> def verify(cookie, sig):
...     good_sig = sign(cookie)
...     return compare_digest(good_sig, sig)
>>>
>>> cookie = b'user-alice'
>>> sig = sign(cookie)
>>> print("{0},{1}".format(cookie.decode('utf-8'), sig))
user-alice,b'43b3c982cf697e0c5ab22172d1ca7421'
>>> verify(cookie, sig)
True
>>> verify(b'user-bob', sig)
False
>>> verify(cookie, b'0102030405060708090a0b0c0d0e0f00')
False

네이티브 키 해싱 모드가 있더라도, 물론 BLAKE2를 hmac 모듈을 사용하여 HMAC 구성에 사용할 수 있습니다:

>>> import hmac, hashlib
>>> m = hmac.new(b'secret key', digestmod=hashlib.blake2s)
>>> m.update(b'message')
>>> m.hexdigest()
'e3c8102868d28b5ff85fc35dda07329970d1a01e273c37481326fe0c861c8142'

무작위 해싱

salt 매개 변수를 설정하면 해시 함수에 무작위화를 도입할 수 있습니다. 무작위 해싱은 디지털 서명에 사용된 해시 함수에 대한 충돌 공격(collision attacks)을 방지하는 데 유용합니다.

무작위 해싱은 한 당사자(메시지 준비자)가 두 번째 당사자(메시지 서명자)가 서명할 메시지의 전부나 일부를 생성하는 상황을 위해 설계되었습니다. 메시지 준비자가 암호화 해시 함수 충돌(즉, 같은 해시값을 생성하는 두 메시지)을 찾을 수 있으면, 같은 해시값과 디지털 서명을 생성하는 의미 있는 메시지 버전을 준비할 수 있지만, 결과는 다릅니다 (예를 들어, 계정으로 $10 대신에 $1,000,000을 이체하는 행위). 암호화 해시 함수는 주요 목표로 충돌 내성을 갖도록 설계되었지만, 현재 암호화 해시 함수 공격에 대한 집중으로 인해 주어진 암호화 해시 함수가 예상보다 적은 충돌 내성을 제공할 수 있습니다. 무작위 해싱은 준비자가 디지털 서명 생성 프로세스 동안 궁극적으로 같은 해시값을 산출하는 두 개 이상의 메시지를 생성할 가능성을 줄여서, 서명자에게 추가적인 보호를 제공합니다 – 설사 해시 함수의 충돌을 찾는 것이 실용적이더라도. 그러나, 무작위 해싱을 사용하면 메시지의 모든 부분을 서명자가 준비할 때 디지털 서명이 제공하는 보안의 양을 줄일 수 있습니다.

(NIST SP-800-106 “Randomized Hashing for Digital Signatures” [https://csrc.nist.gov/pubs/sp/800/106/final])

BLAKE2에서 솔트는 각 압축 함수에 대한 입력이 아니라 초기화 중에 해시 함수에 대한 일회성 입력으로 처리됩니다.

경고

Salted hashing (or just hashing) with BLAKE2 or any other general-purpose cryptographic hash function, such as SHA-256, is not suitable for hashing passwords. See BLAKE2 FAQ [https://www.blake2.net/#qa] for more information.

>>> import os
>>> from hashlib import blake2b
>>> msg = b'some message'
>>> # Calculate the first hash with a random salt.
>>> salt1 = os.urandom(blake2b.SALT_SIZE)
>>> h1 = blake2b(salt=salt1)
>>> h1.update(msg)
>>> # Calculate the second hash with a different random salt.
>>> salt2 = os.urandom(blake2b.SALT_SIZE)
>>> h2 = blake2b(salt=salt2)
>>> h2.update(msg)
>>> # The digests are different.
>>> h1.digest() != h2.digest()
True

개인화

때로는 해시 함수가 다른 목적으로 같은 입력에 대해 다른 요약을 생성하도록 강제하는 것이 유용합니다. Skein 해시 함수의 저자를 인용합니다:

모든 응용 프로그램 설계자는 이렇게 하는 것을 진지하게 고려하도록 권장합니다; 우리는 유사하거나 관련된 데이터에 대해 두 해시 계산이 수행되었기 때문에, 프로토콜의 한 부분에서 계산된 해시가 완전히 다른 부분에서 사용될 수 있는 프로토콜을 많이 보았으며, 공격자는 응용 프로그램이 해시 입력을 갖게 만들도록 강제할 수 있습니다. 프로토콜에 사용된 각 해시 함수를 개인화하면 이러한 유형의 공격이 중단됩니다.

(The Skein Hash Function Family [https://www.schneier.com/wp-content/uploads/2016/02/skein.pdf], p. 21)

BLAKE2는 바이트열을 person 인자에 전달하여 개인화할 수 있습니다:

>>> from hashlib import blake2b
>>> FILES_HASH_PERSON = b'MyApp Files Hash'
>>> BLOCK_HASH_PERSON = b'MyApp Block Hash'
>>> h = blake2b(digest_size=32, person=FILES_HASH_PERSON)
>>> h.update(b'the same content')
>>> h.hexdigest()
'20d9cd024d4fb086aae819a1432dd2466de12947831b75c5a30cf2676095d3b4'
>>> h = blake2b(digest_size=32, person=BLOCK_HASH_PERSON)
>>> h.update(b'the same content')
>>> h.hexdigest()
'cf68fb5761b9c44e7878bfb2c4c9aea52264a80b75005e65619778de59f383a3'

키 모드와 함께 개인화를 사용하여, 한 키에서 다른 키들을 파생시킬 수도 있습니다.

>>> from hashlib import blake2s
>>> from base64 import b64decode, b64encode
>>> orig_key = b64decode(b'Rm5EPJai72qcK3RGBpW3vPNfZy5OZothY+kHY6h21KM=')
>>> enc_key = blake2s(key=orig_key, person=b'kEncrypt').digest()
>>> mac_key = blake2s(key=orig_key, person=b'kMAC').digest()
>>> print(b64encode(enc_key).decode('utf-8'))
rbPb15S/Z9t+agffno5wuhB77VbRi6F9Iv2qIxU7WHw=
>>> print(b64encode(mac_key).decode('utf-8'))
G9GtHFE1YluXY1zWPlYk1e/nWfu0WSEb0KRcjhDeP/o=

트리 모드

다음은 두 개의 리프 노드를 갖는 최소 트리를 해싱하는 예입니다:

  10
 /  \
00  01

이 예는 64바이트 내부 요약을 사용하고, 32바이트 최종 요약을 반환합니다:

>>> from hashlib import blake2b
>>>
>>> FANOUT = 2
>>> DEPTH = 2
>>> LEAF_SIZE = 4096
>>> INNER_SIZE = 64
>>>
>>> buf = bytearray(6000)
>>>
>>> # Left leaf
... h00 = blake2b(buf[0:LEAF_SIZE], fanout=FANOUT, depth=DEPTH,
...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
...               node_offset=0, node_depth=0, last_node=False)
>>> # Right leaf
... h01 = blake2b(buf[LEAF_SIZE:], fanout=FANOUT, depth=DEPTH,
...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
...               node_offset=1, node_depth=0, last_node=True)
>>> # Root node
... h10 = blake2b(digest_size=32, fanout=FANOUT, depth=DEPTH,
...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
...               node_offset=0, node_depth=1, last_node=True)
>>> h10.update(h00.digest())
>>> h10.update(h01.digest())
>>> h10.hexdigest()
'3ad2a9b37c6070e374c7a8c508fe20ca86b6ed54e286e93a0318e95e881db5aa'

크레딧

BLAKE2 [https://www.blake2.net]는 Jean-Philippe Aumasson, Luca Henzen, Willi Meier 및 Raphael C.-W. Phan이 만든 SHA-3 [https://en.wikipedia.org/wiki/Secure_Hash_Algorithms] 파이널리스트 BLAKE [https://web.archive.org/web/20200918190133/https://131002.net/blake/]를 기반으로 Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O’Hearn 및 Christian Winnerlein이 설계했습니다.

Daniel J. Bernstein이 설계한 ChaCha [https://cr.yp.to/chacha.html] 암호(cipher)의 핵심 알고리즘을 사용합니다.

표준 라이브러리 구현은 pyblake2 [https://pythonhosted.org/pyblake2/] 모듈에 기반합니다. 이것은 Samuel Neves가 작성한 C 구현을 기반으로 Dmitry Chestnykh가 작성했습니다. 이 설명서는 pyblake2 [https://pythonhosted.org/pyblake2/]에서 복사했으며 Dmitry Chestnykh가 작성했습니다.

C 코드는 Christian Heimes가 파이썬 용으로 부분적으로 재작성했습니다.

다음 공개 도메인 기부는 C 해시 함수 구현, 확장 코드 및 이 설명서 모두에 적용됩니다:

법률에 따라 가능한 범위 내에서, 저자(들)는 이 소프트웨어에 대한 모든 저작권과 관련되고 둘러싼 권리를 전 세계 공개 도메인에 기부했습니다. 이 소프트웨어는 보증 없이 배포됩니다.

이 소프트웨어와 함께 CC0 Public Domain Dedication의 사본을 받았어야 합니다. 그렇지 않으면, https://creativecommons.org/publicdomain/zero/1.0/ 을 참조하십시오.

다음과 같은 사람들은 Creative Commons Public Domain Dedication 1.0 Universal에 따라 개발을 돕거나 프로젝트와 공개 도메인에 변경에 기여했습니다:

Alexandr Sokolovskiy

더 보기

모듈 hmac

해시를 사용하여 메시지 인증 코드를 생성하는 모듈.

모듈 base64

바이너리가 아닌 환경을 위해 바이너리 해시를 인코딩하는 다른 방법.

https://nvlpubs.nist.gov/nistpubs/fips/nist.fips.180-4.pdf

The FIPS 180-4 publication on Secure Hash Algorithms.

https://csrc.nist.gov/pubs/fips/202/final

The FIPS 202 publication on the SHA-3 Standard.

https://www.blake2.net/

공식 BLAKE2 웹 사이트.

https://en.wikipedia.org/wiki/Cryptographic_hash_function

어떤 알고리즘에 알려진 문제가 있고 그것이 사용에 어떤 의미가 있는지에 대한 정보가 포함된 위키피디아 기사.

https://www.ietf.org/rfc/rfc8018.txt

PKCS #5: Password-Based Cryptography Specification Version 2.1

https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf

NIST Recommendation for Password-Based Key Derivation.

hmac — Keyed-Hashing for Message Authentication

소스 코드: Lib/hmac.py [https://github.com/python/cpython/tree/main/Lib/hmac.py]

이 모듈은 RFC 2104 [https://datatracker.ietf.org/doc/html/rfc2104.html]에서 설명한 대로 HMAC 알고리즘을 구현합니다.

hmac.new(key, msg=None, digestmod)

새로운 hmac 객체를 반환합니다. key는 비밀 키를 제공하는 바이트열이나 바이트 배열(bytearray) 객체입니다. msg가 있으면, update(msg) 메서드 호출이 수행됩니다. digestmod는 다이제스트 이름, 다이제스트 생성자 또는 HMAC 객체가 사용할 모듈입니다. hashlib.new()에 적합한 모든 이름일 수 있습니다. 인자의 위치에도 불구하고, 필수입니다.

버전 3.4에서 변경: 매개 변수 key는 바이트열 또는 바이트 배열 객체일 수 있습니다. 매개 변수 msg는 hashlib가 지원하는 모든 형이 될 수 있습니다. 매개 변수 digestmod는 해시 알고리즘의 이름이 될 수 있습니다.

버전 3.8에서 변경: The digestmod argument is now required. Pass it as a keyword argument to avoid awkwardness when you do not have an initial msg.

hmac.digest(key, msg, digest)

주어진 비밀 key 와 digest로 msg의 다이제스트를 반환합니다. 이 함수는 HMAC(key, msg, digest).digest()와 동등하지만, 최적화된 C 나 인라인 구현을 사용해서, 메모리에 맞는 메시지에는 더 빠릅니다. 매개 변수 key, msg 및 digest는 new()에서와 같은 뜻입니다.

CPython 구현 세부 사항, 최적화된 C 구현은 digest가 문자열이고 OpenSSL에서 지원하는 다이제스트 알고리즘의 이름일 때만 사용됩니다.

Added in version 3.7.

HMAC 객체에는 다음과 같은 메서드가 있습니다:

HMAC.update(msg)

hmac 객체를 msg로 갱신합니다. 반복되는 호출은 모든 인자를 이어붙인 단일 호출과 동등합니다: m.update(a); m.update(b)는 m.update(a + b)와 동등합니다.

버전 3.4에서 변경: 매개 변수 msg는 hashlib가 지원하는 모든 형이 될 수 있습니다.

HMAC.digest()

지금까지 update() 메서드로 전달된 바이트들의 다이제스트를 반환합니다. 이 바이트열 객체는 생성자에게 주어진 다이제스트의 digest_size와 길이가 같습니다. NUL 바이트를 포함하여 비 ASCII 바이트를 포함할 수 있습니다.

경고

When comparing the output of digest() to an externally supplied digest during a verification routine, it is recommended to use the compare_digest() function instead of the == operator to reduce the vulnerability to timing attacks.

HMAC.hexdigest()

다이제스트가 16진수만 포함하는 길이가 두 배인 문자열로 반환된다는 점을 제외하고는 digest()와 같습니다. 이것은 전자 메일이나 기타 비 바이너리 환경에서 값을 안전하게 교환하는 데 사용될 수 있습니다.

경고

When comparing the output of hexdigest() to an externally supplied digest during a verification routine, it is recommended to use the compare_digest() function instead of the == operator to reduce the vulnerability to timing attacks.

HMAC.copy()

hmac 객체의 복사본(“클론”)을 반환합니다. 이것은 공통 초기 부분 문자열을 공유하는 문자열들의 다이제스트를 효율적으로 계산하는 데 사용할 수 있습니다.

hmac 객체에는 다음과 같은 어트리뷰트가 있습니다:

HMAC.digest_size

결과 HMAC 다이제스트의 크기(바이트).

HMAC.block_size

해시 알고리즘의 내부 블록 크기(바이트).

Added in version 3.4.

HMAC.name

이 HMAC의 규범적 이름, 항상 소문자, 예를 들어 hmac-md5.

Added in version 3.4.

버전 3.10에서 변경: Removed the undocumented attributes HMAC.digest_cons, HMAC.inner, and HMAC.outer.

이 모듈은 또한 다음 도우미 함수를 제공합니다:

hmac.compare_digest(a, b)

a == b를 반환합니다. 이 함수는 내용 기반의 단락(short circuiting) 동작을 피함으로써 타이밍 분석을 방지하도록 설계된 접근법을 사용해서 암호화에 적합하게 만듭니다. a와 b는 모두 같은 형이어야 합니다: str (ASCII만, 예를 들어 HMAC.hexdigest()에 의해 반환된 것과 같은 것) 이나 바이트열류 객체.

참고

a와 b의 길이가 다르거나 에러가 발생하면, 타이밍 공격이 이론적으로는 a 와 b의 형과 길이에 관한 정보를 드러낼 수 있습니다 - 하지만 그 값은 아닙니다.

Added in version 3.3.

버전 3.10에서 변경: 이 함수는 사용할 수 있으면 내부적으로 OpenSSL의 CRYPTO_memcmp()를 사용합니다.

더 보기

모듈 hashlib

안전한 해시 함수를 제공하는 파이썬 모듈.

secrets — Generate secure random numbers for managing secrets

Added in version 3.6.

소스 코드: Lib/secrets.py [https://github.com/python/cpython/tree/main/Lib/secrets.py]

secrets 모듈은 암호, 계정 인증, 보안 토큰 및 관련 비밀과 같은 데이터를 관리하는 데 적합한 암호학적으로 강력한 난수를 생성하는 데 사용됩니다.

특히, secrets는 보안이나 암호화가 아닌 모델링과 시뮬레이션용으로 설계된 random 모듈의 기본 의사 난수 생성기보다 먼저 사용해야 합니다.

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PEP 506 [https://peps.python.org/pep-0506/]

난수

secrets 모듈은 운영 체제가 제공하는 가장 안전한 무작위 소스에 대한 액세스를 제공합니다.

class secrets.SystemRandom

운영 체제에서 제공하는 최고 품질의 소스를 사용하여 난수를 생성하는 클래스. 자세한 내용은 random.SystemRandom를 참조하십시오.

secrets.choice(seq)

Return a randomly chosen element from a non-empty sequence.

secrets.randbelow(exclusive_upper_bound)

Return a random int in the range [0, exclusive_upper_bound).

secrets.randbits(k)

Return a non-negative int with k random bits.

토큰 생성

secrets 모듈은 암호 재설정, 추측하기 어려운 URL 등과 같은 응용에 적합한 보안 토큰을 생성하는 함수를 제공합니다.

secrets.token_bytes([nbytes=None])

nbytes 바이트를 포함하는 임의의 바이트열을 반환합니다. nbytes가 None이거나 제공되지 않으면, 적절한 기본값이 사용됩니다.

>>> token_bytes(16)
b'\xebr\x17D*t\xae\xd4\xe3S\xb6\xe2\xebP1\x8b'

secrets.token_hex([nbytes=None])

무작위 16진수 텍스트 문자열을 돌려줍니다. 이 문자열에는 nbytes 무작위 바이트가 있으며, 각 바이트는 두 자리 16진수로 변환됩니다. nbytes가 None이거나 제공되지 않으면, 적절한 기본값이 사용됩니다.

>>> token_hex(16)
'f9bf78b9a18ce6d46a0cd2b0b86df9da'

secrets.token_urlsafe([nbytes=None])

nbytes의 무작위 바이트를 포함한, URL 안전한 무작위 텍스트 문자열을 돌려줍니다. 텍스트는 Base64로 인코딩되어 있으므로, 평균적으로 각 바이트는 약 1.3 문자가 됩니다. nbytes가 None이거나 제공되지 않으면, 적절한 기본값이 사용됩니다.

>>> token_urlsafe(16)
'Drmhze6EPcv0fN_81Bj-nA'

토큰은 몇 바이트를 사용해야 합니까?

무차별 공격 [https://en.wikipedia.org/wiki/Brute-force_attack]으로부터 안전하려면, 토큰에 충분한 무작위성이 있어야 합니다. 불행하게도, 컴퓨터가 더 강력해지고 더 짧은 기간에 더 많은 추측을 할 수 있게 됨에 따라, 충분하다고 여겨지는 것은 필연적으로 증가합니다. 2015년 현재, secrets 모듈로 예상되는 일반적인 사용 사례에는 32바이트(256비트)의 무작위성으로 충분하다고 여겨집니다.

자신의 토큰 길이를 관리하려는 사용자는, 여러 token_* 함수에 int 인자를 제공하여 토큰에 사용되는 무작위성의 양을 명시적으로 지정할 수 있습니다. 이 인자는 사용할 무작위성의 바이트 수로 사용됩니다.

그렇지 않으면, 인자가 제공되지 않거나 인자가 None 이면, token_* 함수는 적절한 기본값을 대신 사용합니다.

참고

이 기본값은 유지 보수 배포를 포함하여 언제든지 변경될 수 있습니다.

기타 함수

secrets.compare_digest(a, b)

Return True if strings or bytes-like objects a and b are equal, otherwise False, using a “constant-time compare” to reduce the risk of timing attacks [https://codahale.com/a-lesson-in-timing-attacks/]. See hmac.compare_digest() for additional details.

조리법과 모범 사례

이 절에서는 secrets를 사용하여 기본 보안 수준을 관리하는 조리법과 모범 사례를 보여줍니다.

8문자 영숫자 암호 생성합니다:

import string
import secrets
alphabet = string.ascii_letters + string.digits
password = ''.join(secrets.choice(alphabet) for i in range(8))

참고

Applications should not store passwords in a recoverable format [https://cwe.mitre.org/data/definitions/257.html], whether plain text or encrypted. They should be salted and hashed using a cryptographically strong one-way (irreversible) hash function.

적어도 하나의 소문자, 적어도 하나의 대문자 및 적어도 3개의 숫자가 있는 10자의 영숫자 암호를 생성합니다:

import string
import secrets
alphabet = string.ascii_letters + string.digits
while True:
    password = ''.join(secrets.choice(alphabet) for i in range(10))
    if (any(c.islower() for c in password)
            and any(c.isupper() for c in password)
            and sum(c.isdigit() for c in password) >= 3):
        break

XKCD-스타일 암호문 [https://xkcd.com/936/]을 생성합니다:

import secrets
# On standard Linux systems, use a convenient dictionary file.
# Other platforms may need to provide their own word-list.
with open('/usr/share/dict/words') as f:
    words = [word.strip() for word in f]
    password = ' '.join(secrets.choice(words) for i in range(4))

암호 복구 응용에 적합한 보안 토큰을 포함하는 추측하기 어려운 임시 URL을 생성합니다:

import secrets
url = 'https://example.com/reset=' + secrets.token_urlsafe()

일반 운영 체제 서비스

이 장에서 설명하는 모듈은 파일 및 시계와 같은 (거의) 모든 운영 체제에서 사용할 수 있는 운영 체제 기능에 대한 인터페이스를 제공합니다. 인터페이스는 일반적으로 유닉스 또는 C 인터페이스를 모델로 하지만, 대부분의 다른 시스템에서도 사용할 수 있습니다. 다음은 개요입니다:

os — Miscellaneous operating system interfaces

error

name

파일명, 명령 줄 인자 및 환경 변수

Python UTF-8 Mode

프로세스 매개 변수

ctermid()

environ

environb

reload_environ()

fsencode()

fsdecode()

fspath()

PathLike

__fspath__()

getenv()

getenvb()

get_exec_path()

getegid()

geteuid()

getgid()

getgrouplist()

getgroups()

getlogin()

getpgid()

getpgrp()

getpid()

getppid()

getpriority()

PRIO_PROCESS

PRIO_PGRP

PRIO_USER

PRIO_DARWIN_THREAD

PRIO_DARWIN_PROCESS

PRIO_DARWIN_BG

PRIO_DARWIN_NONUI

getresuid()

getresgid()

getuid()

initgroups()

putenv()

setegid()

seteuid()

setgid()

setgroups()

setns()

setpgrp()

setpgid()

setpriority()

setregid()

setresgid()

setresuid()

setreuid()

getsid()

setsid()

setuid()

strerror()

supports_bytes_environ

umask()

uname()

unsetenv()

unshare()

CLONE_FILES

CLONE_FS

CLONE_NEWCGROUP

CLONE_NEWIPC

CLONE_NEWNET

CLONE_NEWNS

CLONE_NEWPID

CLONE_NEWTIME

CLONE_NEWUSER

CLONE_NEWUTS

CLONE_SIGHAND

CLONE_SYSVSEM

CLONE_THREAD

CLONE_VM

파일 객체 생성

fdopen()

파일 기술자 연산

close()

closerange()

copy_file_range()

device_encoding()

dup()

dup2()

fchmod()

fchown()

fdatasync()

fpathconf()

fstat()

fstatvfs()

fsync()

ftruncate()

get_blocking()

grantpt()

isatty()

lockf()

F_LOCK

F_TLOCK

F_ULOCK

F_TEST

login_tty()

lseek()

SEEK_SET

SEEK_CUR

SEEK_END

SEEK_HOLE

SEEK_DATA

open()

O_RDONLY

O_WRONLY

O_RDWR

O_APPEND

O_CREAT

O_EXCL

O_TRUNC

O_DSYNC

O_RSYNC

O_SYNC

O_NDELAY

O_NONBLOCK

O_NOCTTY

O_CLOEXEC

O_BINARY

O_NOINHERIT

O_SHORT_LIVED

O_TEMPORARY

O_RANDOM

O_SEQUENTIAL

O_TEXT

O_EVTONLY

O_FSYNC

O_SYMLINK

O_NOFOLLOW_ANY

O_ASYNC

O_DIRECT

O_DIRECTORY

O_NOFOLLOW

O_NOATIME

O_PATH

O_TMPFILE

O_SHLOCK

O_EXLOCK

openpty()

pipe()

pipe2()

posix_fallocate()

posix_fadvise()

POSIX_FADV_NORMAL

POSIX_FADV_SEQUENTIAL

POSIX_FADV_RANDOM

POSIX_FADV_NOREUSE

POSIX_FADV_WILLNEED

POSIX_FADV_DONTNEED

pread()

posix_openpt()

preadv()

RWF_NOWAIT

RWF_HIPRI

ptsname()

pwrite()

pwritev()

RWF_DSYNC

RWF_SYNC

RWF_APPEND

read()

sendfile()

SF_NODISKIO

SF_MNOWAIT

SF_SYNC

SF_NOCACHE

set_blocking()

splice()

SPLICE_F_MOVE

SPLICE_F_NONBLOCK

SPLICE_F_MORE

readv()

tcgetpgrp()

tcsetpgrp()

ttyname()

unlockpt()

write()

writev()

터미널의 크기 조회하기

get_terminal_size()

terminal_size

columns

lines

파일 기술자의 상속

get_inheritable()

set_inheritable()

get_handle_inheritable()

set_handle_inheritable()

파일과 디렉터리

access()

F_OK

R_OK

W_OK

X_OK

chdir()

chflags()

chmod()

chown()

chroot()

fchdir()

getcwd()

getcwdb()

lchflags()

lchmod()

lchown()

link()

listdir()

listdrives()

listmounts()

listvolumes()

lstat()

mkdir()

makedirs()

mkfifo()

mknod()

major()

minor()

makedev()

pathconf()

pathconf_names

readlink()

remove()

removedirs()

rename()

renames()

replace()

rmdir()

scandir()

close()

DirEntry

name

path

inode()

is_dir()

is_file()

is_symlink()

is_junction()

stat()

stat()

stat_result

st_mode

st_ino

st_dev

st_nlink

st_uid

st_gid

st_size

st_atime

st_mtime

st_ctime

st_atime_ns

st_mtime_ns

st_ctime_ns

st_birthtime

st_birthtime_ns

st_blocks

st_blksize

st_rdev

st_flags

st_gen

st_fstype

st_rsize

st_creator

st_type

st_file_attributes

st_reparse_tag

statvfs()

supports_dir_fd

supports_effective_ids

supports_fd

supports_follow_symlinks

symlink()

sync()

truncate()

unlink()

utime()

walk()

fwalk()

memfd_create()

MFD_CLOEXEC

MFD_ALLOW_SEALING

MFD_HUGETLB

MFD_HUGE_SHIFT

MFD_HUGE_MASK

MFD_HUGE_64KB

MFD_HUGE_512KB

MFD_HUGE_1MB

MFD_HUGE_2MB

MFD_HUGE_8MB

MFD_HUGE_16MB

MFD_HUGE_32MB

MFD_HUGE_256MB

MFD_HUGE_512MB

MFD_HUGE_1GB

MFD_HUGE_2GB

MFD_HUGE_16GB

eventfd()

eventfd_read()

eventfd_write()

EFD_CLOEXEC

EFD_NONBLOCK

EFD_SEMAPHORE

Timer File Descriptors

timerfd_create()

timerfd_settime()

timerfd_settime_ns()

timerfd_gettime()

timerfd_gettime_ns()

TFD_NONBLOCK

TFD_CLOEXEC

TFD_TIMER_ABSTIME

TFD_TIMER_CANCEL_ON_SET

리눅스 확장 어트리뷰트

getxattr()

listxattr()

removexattr()

setxattr()

XATTR_SIZE_MAX

XATTR_CREATE

XATTR_REPLACE

프로세스 관리

abort()

add_dll_directory()

execl()

execle()

execlp()

execlpe()

execv()

execve()

execvp()

execvpe()

_exit()

EX_OK

EX_USAGE

EX_DATAERR

EX_NOINPUT

EX_NOUSER

EX_NOHOST

EX_UNAVAILABLE

EX_SOFTWARE

EX_OSERR

EX_OSFILE

EX_CANTCREAT

EX_IOERR

EX_TEMPFAIL

EX_PROTOCOL

EX_NOPERM

EX_CONFIG

EX_NOTFOUND

fork()

forkpty()

kill()

killpg()

nice()

pidfd_open()

PIDFD_NONBLOCK

plock()

popen()

posix_spawn()

POSIX_SPAWN_OPEN

POSIX_SPAWN_CLOSE

POSIX_SPAWN_DUP2

POSIX_SPAWN_CLOSEFROM

posix_spawnp()

register_at_fork()

spawnl()

spawnle()

spawnlp()

spawnlpe()

spawnv()

spawnve()

spawnvp()

spawnvpe()

P_NOWAIT

P_NOWAITO

P_WAIT

P_DETACH

P_OVERLAY

startfile()

system()

times()

wait()

waitid()

waitpid()

wait3()

wait4()

P_PID

P_PGID

P_ALL

P_PIDFD

WCONTINUED

WEXITED

WSTOPPED

WUNTRACED

WNOHANG

WNOWAIT

CLD_EXITED

CLD_KILLED

CLD_DUMPED

CLD_TRAPPED

CLD_STOPPED

CLD_CONTINUED

waitstatus_to_exitcode()

WCOREDUMP()

WIFCONTINUED()

WIFSTOPPED()

WIFSIGNALED()

WIFEXITED()

WEXITSTATUS()

WSTOPSIG()

WTERMSIG()

스케줄러에 대한 인터페이스

SCHED_OTHER

SCHED_BATCH

SCHED_IDLE

SCHED_SPORADIC

SCHED_FIFO

SCHED_RR

SCHED_RESET_ON_FORK

sched_param

sched_priority

sched_get_priority_min()

sched_get_priority_max()

sched_setscheduler()

sched_getscheduler()

sched_setparam()

sched_getparam()

sched_rr_get_interval()

sched_yield()

sched_setaffinity()

sched_getaffinity()

기타 시스템 정보

confstr()

confstr_names

cpu_count()

getloadavg()

process_cpu_count()

sysconf()

sysconf_names

curdir

pardir

sep

altsep

extsep

pathsep

defpath

linesep

devnull

RTLD_LAZY

RTLD_NOW

RTLD_GLOBAL

RTLD_LOCAL

RTLD_NODELETE

RTLD_NOLOAD

RTLD_DEEPBIND

난수

getrandom()

urandom()

GRND_NONBLOCK

GRND_RANDOM

io — Core tools for working with streams

개요

텍스트 I/O

바이너리 I/O

원시 I/O

Text Encoding

Opt-in EncodingWarning

고수준 모듈 인터페이스

DEFAULT_BUFFER_SIZE

open()

open_code()

text_encoding()

BlockingIOError

UnsupportedOperation

클래스 위계

I/O 베이스 클래스

IOBase

close()

closed

fileno()

flush()

isatty()

readable()

readline()

readlines()

seek()

seekable()

tell()

truncate()

writable()

writelines()

__del__()

RawIOBase

read()

readall()

readinto()

write()

BufferedIOBase

raw

detach()

read()

read1()

readinto()

readinto1()

write()

원시 파일 I/O

FileIO

mode

name

버퍼링 된 스트림

BytesIO

getbuffer()

getvalue()

read1()

readinto1()

BufferedReader

peek()

read()

read1()

BufferedWriter

flush()

write()

BufferedRandom

BufferedRWPair

텍스트 I/O

TextIOBase

encoding

errors

newlines

buffer

detach()

read()

readline()

seek()

tell()

write()

TextIOWrapper

line_buffering

write_through

reconfigure()

seek()

tell()

StringIO

getvalue()

IncrementalNewlineDecoder

성능

바이너리 I/O

텍스트 I/O

다중 스레드

재진입

time — Time access and conversions

함수

asctime()

pthread_getcpuclockid()

clock_getres()

clock_gettime()

clock_gettime_ns()

clock_settime()

clock_settime_ns()

ctime()

get_clock_info()

gmtime()

localtime()

mktime()

monotonic()

monotonic_ns()

perf_counter()

perf_counter_ns()

process_time()

process_time_ns()

sleep()

strftime()

strptime()

struct_time

tm_year

tm_mon

tm_mday

tm_hour

tm_min

tm_sec

tm_wday

tm_yday

tm_isdst

tm_zone

tm_gmtoff

time()

time_ns()

thread_time()

thread_time_ns()

tzset()

시계 ID 상수

CLOCK_BOOTTIME

CLOCK_HIGHRES

CLOCK_MONOTONIC

CLOCK_MONOTONIC_RAW

CLOCK_MONOTONIC_RAW_APPROX

CLOCK_PROCESS_CPUTIME_ID

CLOCK_PROF

CLOCK_TAI

CLOCK_THREAD_CPUTIME_ID

CLOCK_UPTIME

CLOCK_UPTIME_RAW

CLOCK_UPTIME_RAW_APPROX

CLOCK_REALTIME

시간대 상수

altzone

daylight

timezone

tzname

argparse — Parser for command-line options, arguments and subcommands

ArgumentParser 객체

ArgumentParser

prog

usage

description

epilog

parents

formatter_class

RawDescriptionHelpFormatter

RawTextHelpFormatter

ArgumentDefaultsHelpFormatter

MetavarTypeHelpFormatter

prefix_chars

fromfile_prefix_chars

argument_default

allow_abbrev

conflict_handler

add_help

exit_on_error

suggest_on_error

add_argument() 메서드

add_argument()

name or flags

action

BooleanOptionalAction

nargs

const

default

type

choices

required

help

metavar

dest

deprecated

Action 클래스

Action

__call__()

format_usage()

parse_args() 메서드

parse_args()

옵션값 문법

잘못된 인자

- 를 포함하는 인자들

인자 약어 (접두사 일치)

sys.argv 너머

Namespace 객체

Namespace

기타 유틸리티

부속 명령

add_subparsers()

FileType 객체

FileType

인자 그룹

add_argument_group()

상호 배제

add_mutually_exclusive_group()

파서 기본값

set_defaults()

get_default()

도움말 인쇄

print_usage()

print_help()

format_usage()

format_help()

부분 파싱

parse_known_args()

파일 파싱 사용자 정의

convert_arg_line_to_args()

종료 메서드

exit()

error()

혼합 파싱

parse_intermixed_args()

parse_known_intermixed_args()

Registering custom types or actions

register()

Exceptions

ArgumentError

ArgumentTypeError

Argparse 자습서

개념

기본

위치 인자 소개

옵션 인자 소개

짧은 옵션

위치 및 옵션 인자 결합하기

조금 더 발전시키기

Specifying ambiguous arguments

충돌하는 옵션들

How to translate the argparse output

Custom type converters

맺음말

Upgrading optparse code

logging — Logging facility for Python

Logger 객체

Logger

name

level

parent

propagate

handlers

disabled

setLevel()

isEnabledFor()

getEffectiveLevel()

getChild()

getChildren()

debug()

info()

warning()

error()

critical()

log()

exception()

addFilter()

removeFilter()

filter()

addHandler()

removeHandler()

findCaller()

handle()

makeRecord()

hasHandlers()

로깅 수준

NOTSET

DEBUG

INFO

WARNING

ERROR

CRITICAL

Handler 객체

Handler

__init__()

createLock()

acquire()

release()

setLevel()

setFormatter()

addFilter()

removeFilter()

filter()

flush()

close()

handle()

handleError()

format()

emit()

Formatter 객체

Formatter

format()

formatTime()

formatException()

formatStack()

BufferingFormatter

formatHeader()

formatFooter()

format()

Filter 객체

Filter

filter()

LogRecord 객체

LogRecord

getMessage()

LogRecord 어트리뷰트

LoggerAdapter 객체

LoggerAdapter

process()

manager

_log

스레드 안전성

모듈 수준 함수

getLogger()

getLoggerClass()

getLogRecordFactory()

debug()

info()

warning()

error()

critical()

exception()

log()

disable()

addLevelName()

getLevelNamesMapping()

getLevelName()

getHandlerByName()

getHandlerNames()

makeLogRecord()

basicConfig()

shutdown()

setLoggerClass()

setLogRecordFactory()

모듈 수준 어트리뷰트

lastResort

raiseExceptions

warnings 모듈과의 통합

captureWarnings()

logging.config — Logging configuration

구성 함수

dictConfig()

fileConfig()

listen()

stopListening()

Security considerations

구성 딕셔너리 스키마

딕셔너리 스키마 세부사항

증분 구성

객체 연결

사용자 정의 객체

Handler configuration order

외부 객체에 대한 액세스

내부 객체에 대한 액세스

임포트 결정과 사용자 정의 임포터

Configuring QueueHandler and QueueListener

구성 파일 형식

logging.handlers — Logging handlers

StreamHandler

StreamHandler

emit()

flush()

setStream()

terminator

FileHandler

FileHandler

close()

emit()

NullHandler

NullHandler

emit()

handle()

createLock()

WatchedFileHandler

WatchedFileHandler

reopenIfNeeded()

emit()

BaseRotatingHandler

BaseRotatingHandler

namer

rotator

rotation_filename()

rotate()

RotatingFileHandler

RotatingFileHandler

doRollover()

emit()

TimedRotatingFileHandler

TimedRotatingFileHandler

doRollover()

emit()

getFilesToDelete()

SocketHandler

SocketHandler

close()

emit()

handleError()

makeSocket()

makePickle()

send()

createSocket()

DatagramHandler

DatagramHandler

emit()

makeSocket()

send()

SysLogHandler

SysLogHandler

close()

createSocket()

emit()

encodePriority()

mapPriority()

NTEventLogHandler

NTEventLogHandler

close()

emit()

getEventCategory()

getEventType()

getMessageID()

SMTPHandler

SMTPHandler

emit()

getSubject()

MemoryHandler

BufferingHandler

emit()

flush()

shouldFlush()

MemoryHandler

close()

flush()

setTarget()

shouldFlush()

HTTPHandler

HTTPHandler

mapLogRecord()

emit()

QueueHandler

QueueHandler

emit()

prepare()

enqueue()

listener

QueueListener

QueueListener

dequeue()

prepare()

handle()

start()

stop()

enqueue_sentinel()

getpass — Portable password input

getpass()

GetPassWarning

getuser()

curses — Terminal handling for character-cell displays

함수

error

baudrate()

beep()

can_change_color()

cbreak()

color_content()

color_pair()

curs_set()

def_prog_mode()

def_shell_mode()

delay_output()

doupdate()

echo()

endwin()

erasechar()

filter()

flash()

flushinp()

getmouse()

getsyx()

getwin()

has_colors()

has_extended_color_support()

has_ic()

has_il()

has_key()

halfdelay()

init_color()

init_pair()

initscr()

is_term_resized()

isendwin()

keyname()

killchar()

longname()

meta()

mouseinterval()

mousemask()

napms()

newpad()

newwin()

nl()

nocbreak()

noecho()

nonl()

noqiflush()

noraw()

pair_content()

pair_number()

putp()

qiflush()

raw()

reset_prog_mode()

reset_shell_mode()

resetty()

resize_term()

resizeterm()

savetty()

get_escdelay()

set_escdelay()

get_tabsize()

set_tabsize()

setsyx()

setupterm()

start_color()

termattrs()

termname()

tigetflag()

tigetnum()

tigetstr()

tparm()

typeahead()

unctrl()

ungetch()

update_lines_cols()

unget_wch()

ungetmouse()

use_env()

use_default_colors()

wrapper()

창 객체

addch()

addnstr()

addstr()

attroff()

attron()

attrset()

bkgd()

bkgdset()

border()

box()

chgat()

clear()

clearok()

clrtobot()

clrtoeol()

cursyncup()

delch()

deleteln()

derwin()

echochar()

enclose()

encoding

erase()

getbegyx()

getbkgd()

getch()

get_wch()

getkey()

getmaxyx()

getparyx()

getstr()

getyx()

hline()

idcok()

idlok()

immedok()

inch()

insch()

insdelln()

insertln()

insnstr()

insstr()

instr()

is_linetouched()

is_wintouched()

keypad()

leaveok()

move()

mvderwin()

mvwin()

nodelay()

notimeout()

noutrefresh()

overlay()

overwrite()

putwin()

redrawln()

redrawwin()

refresh()

resize()

scroll()

scrollok()

setscrreg()

standend()

standout()

subpad()

subwin()

syncdown()

syncok()

syncup()

timeout()

touchline()

touchwin()

untouchwin()

vline()

상수

ERR

OK

version

__version__

ncurses_version

COLORS

COLOR_PAIRS

COLS

LINES

A_ALTCHARSET

A_BLINK

A_BOLD

A_DIM

A_INVIS

A_ITALIC

A_NORMAL

A_PROTECT

A_REVERSE

A_STANDOUT

A_UNDERLINE

A_HORIZONTAL

A_LEFT

A_LOW

A_RIGHT

A_TOP

A_VERTICAL

A_ATTRIBUTES

A_CHARTEXT

A_COLOR

KEY_MIN

KEY_BREAK

KEY_DOWN

KEY_UP

KEY_LEFT

KEY_RIGHT

KEY_HOME

KEY_BACKSPACE

KEY_F0

KEY_Fn

KEY_DL

KEY_IL

KEY_DC

KEY_IC

KEY_EIC

KEY_CLEAR

KEY_EOS

KEY_EOL

KEY_SF

KEY_SR

KEY_NPAGE

KEY_PPAGE

KEY_STAB

KEY_CTAB

KEY_CATAB

KEY_ENTER

KEY_SRESET

KEY_RESET

KEY_PRINT

KEY_LL

KEY_A1

KEY_A3

KEY_B2

KEY_C1

KEY_C3

KEY_BTAB

KEY_BEG

KEY_CANCEL

KEY_CLOSE

KEY_COMMAND

KEY_COPY

KEY_CREATE

KEY_END

KEY_EXIT

KEY_FIND

KEY_HELP

KEY_MARK

KEY_MESSAGE

KEY_MOVE

KEY_NEXT

KEY_OPEN

KEY_OPTIONS

KEY_PREVIOUS

KEY_REDO

KEY_REFERENCE

KEY_REFRESH

KEY_REPLACE

KEY_RESTART

KEY_RESUME

KEY_SAVE

KEY_SBEG

KEY_SCANCEL

KEY_SCOMMAND

KEY_SCOPY

KEY_SCREATE

KEY_SDC

KEY_SDL

KEY_SELECT

KEY_SEND

KEY_SEOL

KEY_SEXIT

KEY_SFIND

KEY_SHELP

KEY_SHOME

KEY_SIC

KEY_SLEFT

KEY_SMESSAGE

KEY_SMOVE

KEY_SNEXT

KEY_SOPTIONS

KEY_SPREVIOUS

KEY_SPRINT

KEY_SREDO

KEY_SREPLACE

KEY_SRIGHT

KEY_SRSUME

KEY_SSAVE

KEY_SSUSPEND

KEY_SUNDO

KEY_SUSPEND

KEY_UNDO

KEY_MOUSE

KEY_RESIZE

KEY_MAX

ACS_BBSS

ACS_BLOCK

ACS_BOARD

ACS_BSBS

ACS_BSSB

ACS_BSSS

ACS_BTEE

ACS_BULLET

ACS_CKBOARD

ACS_DARROW

ACS_DEGREE

ACS_DIAMOND

ACS_GEQUAL

ACS_HLINE

ACS_LANTERN

ACS_LARROW

ACS_LEQUAL

ACS_LLCORNER

ACS_LRCORNER

ACS_LTEE

ACS_NEQUAL

ACS_PI

ACS_PLMINUS

ACS_PLUS

ACS_RARROW

ACS_RTEE

ACS_S1

ACS_S3

ACS_S7

ACS_S9

ACS_SBBS

ACS_SBSB

ACS_SBSS

ACS_SSBB

ACS_SSBS

ACS_SSSB

ACS_SSSS

ACS_STERLING

ACS_TTEE

ACS_UARROW

ACS_ULCORNER

ACS_URCORNER

ACS_VLINE

BUTTONn_PRESSED

BUTTONn_RELEASED

BUTTONn_CLICKED

BUTTONn_DOUBLE_CLICKED

BUTTONn_TRIPLE_CLICKED

BUTTON_SHIFT

BUTTON_CTRL

BUTTON_ALT

COLOR_BLACK

COLOR_BLUE

COLOR_CYAN

COLOR_GREEN

COLOR_MAGENTA

COLOR_RED

COLOR_WHITE

COLOR_YELLOW

curses.textpad — curses 프로그램을 위한 텍스트 입력 위젯

rectangle()

Textbox 객체

Textbox

edit()

do_command()

gather()

stripspaces

curses.ascii — Utilities for ASCII characters

NUL

SOH

STX

ETX

EOT

ENQ

ACK

BEL

BS

TAB

HT

LF

NL

VT

FF

CR

SO

SI

DLE

DC1

DC2

DC3

DC4

NAK

SYN

ETB

CAN

EM

SUB

ESC

FS

GS

RS

US

SP

DEL

isalnum()

isalpha()

isascii()

isblank()

iscntrl()

isdigit()

isgraph()

islower()

isprint()

ispunct()

isspace()

isupper()

isxdigit()

isctrl()

ismeta()

ascii()

ctrl()

alt()

unctrl()

controlnames

curses.panel — A panel stack extension for curses

함수

bottom_panel()

new_panel()

top_panel()

update_panels()

Panel 객체

above()

below()

bottom()

hidden()

hide()

move()

replace()

set_userptr()

show()

top()

userptr()

window()

platform — Access to underlying platform’s identifying data

크로스 플랫폼

architecture()

machine()

node()

platform()

processor()

python_build()

python_compiler()

python_branch()

python_implementation()

python_revision()

python_version()

python_version_tuple()

release()

system()

system_alias()

version()

uname()

자바 플랫폼

java_ver()

윈도우 플랫폼

win32_ver()

win32_edition()

win32_is_iot()

macOS Platform

mac_ver()

iOS Platform

ios_ver()

유닉스 플랫폼

libc_ver()

Linux Platforms

freedesktop_os_release()

Android Platform

android_ver()

Miscellaneous

invalidate_caches()

errno — Standard errno system symbols

errorcode

EPERM

ENOENT

ESRCH

EINTR

EIO

ENXIO

E2BIG

ENOEXEC

EBADF

ECHILD

EAGAIN

ENOMEM

EACCES

EFAULT

ENOTBLK

EBUSY

EEXIST

EXDEV

ENODEV

ENOTDIR

EISDIR

EINVAL

ENFILE

EMFILE

ENOTTY

ETXTBSY

EFBIG

ENOSPC

ESPIPE

EROFS

EMLINK

EPIPE

EDOM

ERANGE

EDEADLK

ENAMETOOLONG

ENOLCK

ENOSYS

ENOTEMPTY

ELOOP

EWOULDBLOCK

ENOMSG

EIDRM

ECHRNG

EL2NSYNC

EL3HLT

EL3RST

ELNRNG

EUNATCH

ENOCSI

EL2HLT

EBADE

EBADR

EXFULL

ENOANO

EBADRQC

EBADSLT

EDEADLOCK

EBFONT

ENOSTR

ENODATA

ETIME

ENOSR

ENONET

ENOPKG

EREMOTE

ENOLINK

EADV

ESRMNT

ECOMM

EPROTO

EMULTIHOP

EDOTDOT

EBADMSG

EOVERFLOW

ENOTUNIQ

EBADFD

EREMCHG

ELIBACC

ELIBBAD

ELIBSCN

ELIBMAX

ELIBEXEC

EILSEQ

ERESTART

ESTRPIPE

EUSERS

ENOTSOCK

EDESTADDRREQ

EMSGSIZE

EPROTOTYPE

ENOPROTOOPT

EPROTONOSUPPORT

ESOCKTNOSUPPORT

EOPNOTSUPP

ENOTSUP

EPFNOSUPPORT

EAFNOSUPPORT

EADDRINUSE

EADDRNOTAVAIL

ENETDOWN

ENETUNREACH

ENETRESET

ECONNABORTED

ECONNRESET

ENOBUFS

EISCONN

ENOTCONN

ESHUTDOWN

ETOOMANYREFS

ETIMEDOUT

ECONNREFUSED

EHOSTDOWN

EHOSTUNREACH

EALREADY

EINPROGRESS

ESTALE

EUCLEAN

ENOTNAM

ENAVAIL

EISNAM

EREMOTEIO

EDQUOT

EQFULL

ENOTCAPABLE

ECANCELED

EOWNERDEAD

ENOTRECOVERABLE

ctypes — A foreign function library for Python

ctypes 자습서

동적 링크 라이브러리 로드하기

로드된 dll에서 함수에 액세스하기

함수 호출하기

기본 데이터형

함수 호출하기, 계속

Calling variadic functions

사용자 정의 데이터형을 사용하여 함수 호출하기

필수 인자 형 (함수 프로토타입) 지정하기

반환형

포인터 전달하기 (또는: 참조로 매개 변수 전달하기)

구조체와 공용체

Structure/union layout, alignment and byte order

구조체와 공용체의 비트 필드

배열

포인터

형 변환

불완전한 형

콜백 함수

dll에서 내 보낸 값을 액세스하기

의외의 것들

가변 크기 데이터형

ctypes 레퍼런스

공유 라이브러리 찾기

공유 라이브러리 로드하기

CDLL

OleDLL

WinDLL

PyDLL

_handle

_name

LibraryLoader

LoadLibrary()

외부 함수

_CFuncPtr

restype

argtypes

errcheck

함수 프로토타입

CFUNCTYPE()

WINFUNCTYPE()

PYFUNCTYPE()

유틸리티 함수

addressof()

alignment()

byref()

cast()

create_string_buffer()

create_unicode_buffer()

DllCanUnloadNow()

DllGetClassObject()

find_library()

find_msvcrt()

FormatError()

GetLastError()

get_errno()

get_last_error()

memmove()

memset()

POINTER()

pointer()

resize()

set_errno()

set_last_error()

sizeof()

string_at()

WinError()

wstring_at()

데이터형

_CData

from_buffer()

from_buffer_copy()

from_address()

from_param()

in_dll()

_b_base_

_b_needsfree_

_objects

기본 데이터형

_SimpleCData

value

c_byte

c_char

c_char_p

c_double

c_longdouble

c_float

c_double_complex

c_float_complex

c_longdouble_complex

c_int

c_int8

c_int16

c_int32

c_int64

c_long

c_longlong

c_short

c_size_t

c_ssize_t

c_time_t

c_ubyte

c_uint

c_uint8

c_uint16

c_uint32

c_uint64

c_ulong

c_ulonglong

c_ushort

c_void_p

c_wchar

c_wchar_p

c_bool

HRESULT

py_object

구조화된 데이터형

Union

BigEndianUnion

LittleEndianUnion

BigEndianStructure

LittleEndianStructure

Structure

_fields_

_pack_

_align_

_layout_

_anonymous_

배열과 포인터

Array

_length_

_type_

ARRAY()

_Pointer

_type_

contents

Exceptions

ArgumentError

COMError

hresult

text

details

os — Miscellaneous operating system interfaces

소스 코드: Lib/os.py [https://github.com/python/cpython/tree/main/Lib/os.py]

이 모듈은 운영 체제 종속 기능을 사용하는 이식성 있는 방법을 제공합니다. 파일을 읽거나 쓰고 싶으면 open()을 보세요, 경로를 조작하려면 os.path 모듈을 보시고, 명령 줄에서 주어진 모든 파일의 모든 줄을 읽으려면 fileinput 모듈을 보십시오. 임시 파일과 디렉터리를 만들려면 tempfile 모듈을 보시고, 고수준의 파일과 디렉터리 처리는 shutil 모듈을 보십시오.

이러한 기능의 가용성에 대한 참고 사항:

내장된 모든 운영 체제 종속적인 파이썬 모듈의 설계는, 같은 기능을 사용할 수 있는 한, 같은 인터페이스를 사용합니다; 예를 들어, 함수 os.stat(path)는 path 에 대한 stat 정보를 같은 (POSIX 인터페이스에서 기원한) 형식으로 반환합니다.

특정 운영 체제에 고유한 확장도 os 모듈을 통해서 사용할 수 있지만, 이러한 기능을 사용하는 것은 물론 이식성에 대한 위협입니다.

경로 또는 파일명을 받아들이는 모든 함수는 바이트열과 문자열 객체를 모두 허용하며, 경로나 파일명이 반환되면 같은 형의 객체를 반환합니다.

On VxWorks, os.popen, os.fork, os.execv and os.spawn*p* are not supported.

On WebAssembly platforms, Android and iOS, large parts of the os module are not available or behave differently. APIs related to processes (e.g. fork(), execve()) and resources (e.g. nice()) are not available. Others like getuid() and getpid() are emulated or stubs. WebAssembly platforms also lack support for signals (e.g. kill(), wait()).

참고

이 모듈의 모든 함수는, 올바르지 않거나 액세스할 수 없는 파일명과 경로일 때, 또는 올바른 형의 인자이지만, 운영 체제에서 허용하지 않으면 OSError(또는 이것의 서브 클래스)를 발생시킵니다.

exception os.error

내장 OSError 예외의 별칭.

os.name

임포트 된 운영 체제 종속 모듈의 이름. 다음과 같은 이름이 현재 등록되어있습니다: 'posix', 'nt', 'java'.

더 보기

sys.platform has a finer granularity. os.uname() gives system-dependent version information.

platform 모듈은 시스템의 아이덴티티에 대한 자세한 검사를 제공합니다.

파일명, 명령 줄 인자 및 환경 변수

In Python, file names, command line arguments, and environment variables are represented using the string type. On some systems, decoding these strings to and from bytes is necessary before passing them to the operating system. Python uses the filesystem encoding and error handler to perform this conversion (see sys.getfilesystemencoding()).

The filesystem encoding and error handler are configured at Python startup by the PyConfig_Read() function: see filesystem_encoding and filesystem_errors members of PyConfig.

버전 3.1에서 변경: On some systems, conversion using the file system encoding may fail. In this case, Python uses the surrogateescape encoding error handler, which means that undecodable bytes are replaced by a Unicode character U+DCxx on decoding, and these are again translated to the original byte on encoding.

The file system encoding must guarantee to successfully decode all bytes below 128. If the file system encoding fails to provide this guarantee, API functions can raise UnicodeError.

See also the locale encoding.

Python UTF-8 Mode

Added in version 3.7: See PEP 540 [https://peps.python.org/pep-0540/] for more details.

The Python UTF-8 Mode ignores the locale encoding and forces the usage of the UTF-8 encoding:

Use UTF-8 as the filesystem encoding.

sys.getfilesystemencoding() returns 'utf-8'.

locale.getpreferredencoding() returns 'utf-8' (the do_setlocale argument has no effect).

sys.stdin, sys.stdout, and sys.stderr all use UTF-8 as their text encoding, with the surrogateescape error handler being enabled for sys.stdin and sys.stdout (sys.stderr continues to use backslashreplace as it does in the default locale-aware mode)

On Unix, os.device_encoding() returns 'utf-8' rather than the device encoding.

Note that the standard stream settings in UTF-8 mode can be overridden by PYTHONIOENCODING (just as they can be in the default locale-aware mode).

As a consequence of the changes in those lower level APIs, other higher level APIs also exhibit different default behaviours:

Command line arguments, environment variables and filenames are decoded to text using the UTF-8 encoding.

os.fsdecode() and os.fsencode() use the UTF-8 encoding.

open(), io.open(), and codecs.open() use the UTF-8 encoding by default. However, they still use the strict error handler by default so that attempting to open a binary file in text mode is likely to raise an exception rather than producing nonsense data.

The Python UTF-8 Mode is enabled if the LC_CTYPE locale is C or POSIX at Python startup (see the PyConfig_Read() function).

It can be enabled or disabled using the -X utf8 command line option and the PYTHONUTF8 environment variable.

If the PYTHONUTF8 environment variable is not set at all, then the interpreter defaults to using the current locale settings, unless the current locale is identified as a legacy ASCII-based locale (as described for PYTHONCOERCECLOCALE), and locale coercion is either disabled or fails. In such legacy locales, the interpreter will default to enabling UTF-8 mode unless explicitly instructed not to do so.

The Python UTF-8 Mode can only be enabled at the Python startup. Its value can be read from sys.flags.utf8_mode.

See also the UTF-8 mode on Windows and the filesystem encoding and error handler.

더 보기

PEP 686 [https://peps.python.org/pep-0686/]

Python 3.15 will make Python UTF-8 Mode default.

프로세스 매개 변수

이 함수들과 데이터 항목은 현재 프로세스와 사용자에 관한 정보와 관련 연산을 제공합니다.

os.ctermid()

프로세스의 제어 터미널에 해당하는 파일명을 반환합니다.

Availability: Unix, not WASI.

os.environ

A mapping object where keys and values are strings that represent the process environment. For example, environ['HOME'] is the pathname of your home directory (on some platforms), and is equivalent to getenv("HOME") in C.

This mapping is captured the first time the os module is imported, typically during Python startup as part of processing site.py. Changes to the environment made after this time are not reflected in os.environ, except for changes made by modifying os.environ directly.

이 매핑은 환경을 조회하는 것뿐 아니라 환경을 수정하는 데도 사용될 수 있습니다. 매핑이 수정될 때 putenv()가 자동으로 호출됩니다.

유닉스에서, 키와 값은 sys.getfilesystemencoding() 과 'surrogateescape' 에러 처리기를 사용합니다. 다른 인코딩을 사용하려면 environb를 사용하십시오.

On Windows, the keys are converted to uppercase. This also applies when getting, setting, or deleting an item. For example, environ['monty'] = 'python' maps the key 'MONTY' to the value 'python'.

참고

Calling putenv() directly does not change os.environ, so it’s better to modify os.environ.

참고

On some platforms, including FreeBSD and macOS, setting environ may cause memory leaks. Refer to the system documentation for putenv().

You can delete items in this mapping to unset environment variables. unsetenv() will be called automatically when an item is deleted from os.environ, and when one of the pop() or clear() methods is called.

더 보기

The os.reload_environ() function.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]의 병합(|)과 업데이트(|=) 연산자를 지원하도록 갱신되었습니다.

os.environb

Bytes version of environ: a mapping object where both keys and values are bytes objects representing the process environment. environ and environb are synchronized (modifying environb updates environ, and vice versa).

environb is only available if supports_bytes_environ is True.

Added in version 3.2.

버전 3.9에서 변경: PEP 584 [https://peps.python.org/pep-0584/]의 병합(|)과 업데이트(|=) 연산자를 지원하도록 갱신되었습니다.

os.reload_environ()

The os.environ and os.environb mappings are a cache of environment variables at the time that Python started. As such, changes to the current process environment are not reflected if made outside Python, or by os.putenv() or os.unsetenv(). Use os.reload_environ() to update os.environ and os.environb with any such changes to the current process environment.

경고

This function is not thread-safe. Calling it while the environment is being modified in an other thread is an undefined behavior. Reading from os.environ or os.environb, or calling os.getenv() while reloading, may return an empty result.

Added in version 3.14.

os.chdir(path)

os.fchdir(fd)

os.getcwd()

이 함수는 파일과 디렉터리에 설명되어 있습니다.

os.fsencode(filename)

Encode path-like filename to the filesystem encoding and error handler; return bytes unchanged.

fsdecode()는 역 함수입니다.

Added in version 3.2.

버전 3.6에서 변경: os.PathLike 인터페이스를 구현하는 객체를 받아들이도록 지원이 추가되었습니다.

os.fsdecode(filename)

Decode the path-like filename from the filesystem encoding and error handler; return str unchanged.

fsencode()는 역 함수입니다.

Added in version 3.2.

버전 3.6에서 변경: os.PathLike 인터페이스를 구현하는 객체를 받아들이도록 지원이 추가되었습니다.

os.fspath(path)

경로의 파일 시스템 표현을 돌려줍니다.

str이나 bytes가 전달되면, 변경되지 않은 상태로 반환됩니다. 그렇지 않으면 __fspath__()가 호출되고, 해당 값이 str이나 bytes 객체인 한 그 값이 반환됩니다. 다른 모든 경우에는 TypeError가 발생합니다.

Added in version 3.6.

class os.PathLike

파일 시스템 경로를 나타내는 객체(예를 들어 pathlib.PurePath)의 추상 베이스 클래스입니다.

Added in version 3.6.

abstractmethod __fspath__()

객체의 파일 시스템 경로 표현을 돌려줍니다.

이 메서드는 str이나 bytes 객체만 반환해야 하며, str을 선호합니다.

os.getenv(key, default=None)

Return the value of the environment variable key as a string if it exists, or default if it doesn’t. key is a string. Note that since getenv() uses os.environ, the mapping of getenv() is similarly also captured on import, and the function may not reflect future environment changes.

유닉스에서, 키와 값은 sys.getfilesystemencoding() 과 'surrogateescape' 에러 처리기로 디코딩됩니다. 다른 인코딩을 사용하려면 os.getenvb()를 사용하십시오.

Availability: Unix, Windows.

os.getenvb(key, default=None)

Return the value of the environment variable key as bytes if it exists, or default if it doesn’t. key must be bytes. Note that since getenvb() uses os.environb, the mapping of getenvb() is similarly also captured on import, and the function may not reflect future environment changes.

getenvb() is only available if supports_bytes_environ is True.

Availability: Unix.

Added in version 3.2.

os.get_exec_path(env=None)

셸과 비슷하게, 프로세스를 시작할 때 지정된 이름의 실행 파일을 검색할 디렉터리 리스트를 반환합니다. (지정된다면) env 는 PATH를 조회할 환경 변수 딕셔너리 여야 합니다. 기본적으로, env 가 None이면, environ이 사용됩니다.

Added in version 3.2.

os.getegid()

현재 프로세스의 유효(effective) 그룹 ID를 반환합니다. 이것은 현재 프로세스에서 실행 중인 파일의 “set id” 비트에 해당합니다.

Availability: Unix, not WASI.

os.geteuid()

현재 프로세스의 유효(effective) 사용자 ID를 반환합니다.

Availability: Unix, not WASI.

os.getgid()

현재 프로세스의 실제(real) 그룹 ID를 반환합니다.

Availability: Unix.

The function is a stub on WASI, see WebAssembly platforms for more information.

os.getgrouplist(user, group, /)

Return list of group ids that user belongs to. If group is not in the list, it is included; typically, group is specified as the group ID field from the password record for user, because that group ID will otherwise be potentially omitted.

Availability: Unix, not WASI.

Added in version 3.3.

os.getgroups()

현재 프로세스와 관련된 보충(supplemental) 그룹 ID 목록을 반환합니다.

Availability: Unix, not WASI.

참고

On macOS, getgroups() behavior differs somewhat from other Unix platforms. If the Python interpreter was built with a deployment target of 10.5 or earlier, getgroups() returns the list of effective group ids associated with the current user process; this list is limited to a system-defined number of entries, typically 16, and may be modified by calls to setgroups() if suitably privileged. If built with a deployment target greater than 10.5, getgroups() returns the current group access list for the user associated with the effective user id of the process; the group access list may change over the lifetime of the process, it is not affected by calls to setgroups(), and its length is not limited to 16. The deployment target value, MACOSX_DEPLOYMENT_TARGET, can be obtained with sysconfig.get_config_var().

os.getlogin()

프로세스의 제어 터미널에 로그인한 사용자의 이름을 반환합니다. 대부분 목적에서, getpass.getuser()를 사용하는 것이 더 유용한데, 이 함수는 환경 변수 LOGNAME 이나 USERNAME을 검사하여 사용자가 누구인지 알아내고, 현재 실제 사용자 ID의 로그인 이름을 얻기 위해 pwd.getpwuid(os.getuid())[0]로 폴백 하기 때문입니다.

Availability: Unix, Windows, not WASI.

os.getpgid(pid)

프로세스 ID pid 를 갖는 프로세스의 프로세스 그룹 ID를 반환합니다. pid 가 0이면, 현재 프로세스의 프로세스 그룹 id가 반환됩니다.

Availability: Unix, not WASI.

os.getpgrp()

현재 프로세스 그룹의 ID를 반환합니다.

Availability: Unix, not WASI.

os.getpid()

현재의 프로세스 ID를 반환합니다.

The function is a stub on WASI, see WebAssembly platforms for more information.

os.getppid()

부모의 프로세스 ID를 반환합니다. 부모 프로세스가 종료했으면, 유닉스에서 반환된 id는 init 프로세스 (1) 중 하나이며, 윈도우에서는 여전히 같은 id인데, 다른 프로세스에서 이미 재사용했을 수 있습니다.

Availability: Unix, Windows, not WASI.

버전 3.2에서 변경: 윈도우에 대한 지원이 추가되었습니다.

os.getpriority(which, who)

프로그램 스케줄 우선순위를 얻습니다. which 값은 PRIO_PROCESS, PRIO_PGRP 또는 PRIO_USER 중 하나이고, who는 which 에 상대적으로 해석됩니다 (PRIO_PROCESS 면 프로세스 식별자, PRIO_PGRP 면 프로세스 그룹 식별자, PRIO_USER 면 사용자 ID). 0 값의 who는 (각각) 호출하는 프로세스, 호출하는 프로세스의 프로세스 그룹, 호출하는 프로세스의 실제 사용자 ID를 나타냅니다.

Availability: Unix, not WASI.

Added in version 3.3.

os.PRIO_PROCESS

os.PRIO_PGRP

os.PRIO_USER

getpriority() 와 setpriority() 함수의 매개 변숫값

Availability: Unix, not WASI.

Added in version 3.3.

os.PRIO_DARWIN_THREAD

os.PRIO_DARWIN_PROCESS

os.PRIO_DARWIN_BG

os.PRIO_DARWIN_NONUI

getpriority() 와 setpriority() 함수의 매개 변숫값

Availability: macOS

Added in version 3.12.

os.getresuid()

현재 프로세스의 실제(real), 유효(effective) 및 저장된(saved) 사용자 ID를 나타내는 튜플 (ruid, euid, suid)를 반환합니다.

Availability: Unix, not WASI.

Added in version 3.2.

os.getresgid()

현재 프로세스의 실제(real), 유효(effective) 및 저장된(saved) 그룹 ID를 나타내는 튜플 (rgid, egid, sgid)를 반환합니다.

Availability: Unix, not WASI.

Added in version 3.2.

os.getuid()

현재 프로세스의 실제(real) 사용자 ID를 반환합니다.

Availability: Unix.

The function is a stub on WASI, see WebAssembly platforms for more information.

os.initgroups(username, gid, /)

지정된 사용자 이름이 구성원인 모든 그룹과 지정된 그룹 ID로 구성된 그룹 액세스 목록을 초기화하기 위해 시스템 initgroups()를 호출합니다.

Availability: Unix, not WASI, not Android.

Added in version 3.2.

os.putenv(key, value, /)

key 라는 환경 변수를 문자열 value 로 설정합니다. 이러한 환경의 변화는 os.system(), popen() 또는 fork() 및 execv()로 시작된 자식 프로세스에 영향을 줍니다.

Assignments to items in os.environ are automatically translated into corresponding calls to putenv(); however, calls to putenv() don’t update os.environ, so it is actually preferable to assign to items of os.environ. This also applies to getenv() and getenvb(), which respectively use os.environ and os.environb in their implementations.

See also the os.reload_environ() function.

참고

On some platforms, including FreeBSD and macOS, setting environ may cause memory leaks. Refer to the system documentation for putenv().

key, value를 인자로 감사 이벤트(auditing event) os.putenv를 발생시킵니다.

버전 3.9에서 변경: 이 함수는 이제 항상 사용할 수 있습니다.

os.setegid(egid, /)

현재 프로세스의 유효 그룹 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.seteuid(euid, /)

현재 프로세스의 유효 사용자 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.setgid(gid, /)

현재 프로세스의 그룹 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.setgroups(groups, /)

현재 프로세스와 연관된 보충(supplemental) 그룹 ID의 목록을 groups로 설정합니다. groups 는 시퀀스 여야 하며, 각 요소는 그룹을 식별하는 정수여야 합니다. 이 연산은 대개 슈퍼 유저만 사용할 수 있습니다.

Availability: Unix, not WASI.

참고

On macOS, the length of groups may not exceed the system-defined maximum number of effective group ids, typically 16. See the documentation for getgroups() for cases where it may not return the same group list set by calling setgroups().

os.setns(fd, nstype=0)

Reassociate the current thread with a Linux namespace. See the setns(2) [https://manpages.debian.org/setns(2)] and namespaces(7) [https://manpages.debian.org/namespaces(7)] man pages for more details.

If fd refers to a /proc/pid/ns/ link, setns() reassociates the calling thread with the namespace associated with that link, and nstype may be set to one of the CLONE_NEW* constants to impose constraints on the operation (0 means no constraints).

Since Linux 5.8, fd may refer to a PID file descriptor obtained from pidfd_open(). In this case, setns() reassociates the calling thread into one or more of the same namespaces as the thread referred to by fd. This is subject to any constraints imposed by nstype, which is a bit mask combining one or more of the CLONE_NEW* constants, e.g. setns(fd, os.CLONE_NEWUTS | os.CLONE_NEWPID). The caller’s memberships in unspecified namespaces are left unchanged.

fd can be any object with a fileno() method, or a raw file descriptor.

This example reassociates the thread with the init process’s network namespace:

fd = os.open("/proc/1/ns/net", os.O_RDONLY)
os.setns(fd, os.CLONE_NEWNET)
os.close(fd)

Availability: Linux >= 3.0 with glibc >= 2.14.

Added in version 3.12.

더 보기

The unshare() function.

os.setpgrp()

Call the system call setpgrp() or setpgrp(0, 0) depending on which version is implemented (if any). See the Unix manual for the semantics.

Availability: Unix, not WASI.

os.setpgid(pid, pgrp, /)

Call the system call setpgid() to set the process group id of the process with id pid to the process group with id pgrp. See the Unix manual for the semantics.

Availability: Unix, not WASI.

os.setpriority(which, who, priority)

프로그램 스케줄 우선순위를 설정합니다. which 값은 PRIO_PROCESS, PRIO_PGRP 또는 PRIO_USER 중 하나이고, who는 which 에 상대적으로 해석됩니다 (PRIO_PROCESS 면 프로세스 식별자, PRIO_PGRP 면 프로세스 그룹 식별자, PRIO_USER 면 사용자 ID). 0 값의 who는 (각각) 호출하는 프로세스, 호출하는 프로세스의 프로세스 그룹, 호출하는 프로세스의 실제 사용자 ID를 나타냅니다. priority 는 -20에서 19 사이의 값입니다. 기본 우선순위는 0입니다; 우선순위가 낮으면 더 유리하게 스케줄 됩니다.

Availability: Unix, not WASI.

Added in version 3.3.

os.setregid(rgid, egid, /)

현재 프로세스의 실제(real) 및 유효한(effective) 그룹 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.setresgid(rgid, egid, sgid, /)

현재 프로세스의 실제(real), 유효(effective) 및 저장된(saved) 그룹 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

Added in version 3.2.

os.setresuid(ruid, euid, suid, /)

현재 프로세스의 실제(real), 유효(effective) 및 저장된(saved) 사용자 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

Added in version 3.2.

os.setreuid(ruid, euid, /)

현재 프로세스의 실제(real) 및 유효(effective) 사용자 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.getsid(pid, /)

Call the system call getsid(). See the Unix manual for the semantics.

Availability: Unix, not WASI.

os.setsid()

Call the system call setsid(). See the Unix manual for the semantics.

Availability: Unix, not WASI.

os.setuid(uid, /)

현재 프로세스의 사용자 ID를 설정합니다.

Availability: Unix, not WASI, not Android.

os.strerror(code, /)

Return the error message corresponding to the error code in code. On platforms where strerror() returns NULL when given an unknown error number, ValueError is raised.

os.supports_bytes_environ

환경의 원시 OS 형이 바이트열이면 True (예를 들어, 윈도우에서는 False).

Added in version 3.2.

os.umask(mask, /)

현재 숫자 umask를 설정하고 이전 umask를 반환합니다.

The function is a stub on WASI, see WebAssembly platforms for more information.

os.uname()

현재 운영 체제를 식별하는 정보를 반환합니다. 반환 값은 5가지 어트리뷰트를 가진 객체입니다:

sysname - 운영 체제 이름

nodename - 네트워크상의 기계 이름 (구현이 정의)

release - 운영 체제 릴리스

version - 운영 체제 버전

machine - 하드웨어 식별자

하위 호환성을 위해, 이 객체는 이터러블이기도 해서, sysname, nodename, release, version 및 machine이 이 순서로 포함된 5-튜플처럼 작동합니다.

일부 시스템에서는 nodename을 8자나 선행 구성 요소로 자릅니다; 호스트 이름을 얻는 더 좋은 방법은 socket.gethostname() 또는 더 나아가 socket.gethostbyaddr(socket.gethostname())입니다.

On macOS, iOS and Android, this returns the kernel name and version (i.e., 'Darwin' on macOS and iOS; 'Linux' on Android). platform.uname() can be used to get the user-facing operating system name and version on iOS and Android.

Availability: Unix.

버전 3.3에서 변경: 반환형이 튜플에서 이름이 지정된 어트리뷰트를 가진 튜플류 객체로 변경되었습니다.

os.unsetenv(key, /)

key 라는 이름의 환경 변수를 삭제합니다. 이러한 환경 변화는 os.system(), popen() 또는 fork() 및 execv()로 시작된 자식 프로세스에 영향을 줍니다.

Deletion of items in os.environ is automatically translated into a corresponding call to unsetenv(); however, calls to unsetenv() don’t update os.environ, so it is actually preferable to delete items of os.environ.

See also the os.reload_environ() function.

key를 인자로 감사 이벤트(auditing event) os.unsetenv를 발생시킵니다.

버전 3.9에서 변경: 이 함수는 이제 항상 사용할 수 있고 윈도우에서도 사용할 수 있습니다.

os.unshare(flags)

Disassociate parts of the process execution context, and move them into a newly created namespace. See the unshare(2) [https://manpages.debian.org/unshare(2)] man page for more details. The flags argument is a bit mask, combining zero or more of the CLONE_* constants, that specifies which parts of the execution context should be unshared from their existing associations and moved to a new namespace. If the flags argument is 0, no changes are made to the calling process’s execution context.

Availability: Linux >= 2.6.16.

Added in version 3.12.

더 보기

The setns() function.

Flags to the unshare() function, if the implementation supports them. See unshare(2) [https://manpages.debian.org/unshare(2)] in the Linux manual for their exact effect and availability.

os.CLONE_FILES

os.CLONE_FS

os.CLONE_NEWCGROUP

os.CLONE_NEWIPC

os.CLONE_NEWNET

os.CLONE_NEWNS

os.CLONE_NEWPID

os.CLONE_NEWTIME

os.CLONE_NEWUSER

os.CLONE_NEWUTS

os.CLONE_SIGHAND

os.CLONE_SYSVSEM

os.CLONE_THREAD

os.CLONE_VM

파일 객체 생성

이 함수들은 새로운 파일 객체를 만듭니다. (파일 기술자를 여는 것에 관해서는 open()를 참조하십시오.)

os.fdopen(fd, *args, **kwargs)

파일 기술자 fd에 연결된 열린 파일 객체를 반환합니다. 이것은 open() 내장 함수의 별칭이며 같은 인자를 받아들입니다. 유일한 차이점은 fdopen()의 첫 번째 인자는 항상 정수여야 한다는 것입니다.

파일 기술자 연산

이 함수들은 파일 기술자를 사용하여 참조된 I/O 스트림에 작용합니다.

파일 기술자는 현재 프로세스에 의해 열린 파일에 대응하는 작은 정수입니다. 예를 들어, 표준 입력은 보통 파일 기술자 0이고, 표준 출력은 1이며, 표준 에러는 2입니다. 프로세스에 의해 열린 추가 파일은 3, 4, 5 등으로 지정됩니다. “파일 기술자”라는 이름은 약간 기만적입니다; 유닉스 플랫폼에서, 소켓과 파이프도 파일 기술자에 의해 참조됩니다.

fileno() 메서드는 필요할 때 파일 객체와 연관된 파일 기술자를 얻는 데 사용될 수 있습니다. 파일 기술자를 직접 사용하면 파일 객체 메서드를 거치지 않아서, 데이터의 내부 버퍼링과 같은 측면을 무시하게 되는 것에 유의하십시오.

os.close(fd)

파일 기술자 fd를 닫습니다.

참고

이 함수는 저수준 I/O를 위한 것이며, os.open() 또는 pipe()에 의해 반환된 파일 기술자에 적용되어야 합니다. 내장 함수 open() 나 popen() 또는 fdopen()에 의해 반환된 “파일 객체”를 닫으려면, close() 메서드를 사용하십시오.

os.closerange(fd_low, fd_high, /)

에러는 무시하면서, fd_low(포함)부터 fd_high(제외)까지 모든 파일 기술자를 닫습니다. 다음과 동등합니다 (하지만 훨씬 빠릅니다):

for fd in range(fd_low, fd_high):
    try:
        os.close(fd)
    except OSError:
        pass

os.copy_file_range(src, dst, count, offset_src=None, offset_dst=None)

Copy count bytes from file descriptor src, starting from offset offset_src, to file descriptor dst, starting from offset offset_dst. If offset_src is None, then src is read from the current position; respectively for offset_dst.

In Linux kernel older than 5.3, the files pointed to by src and dst must reside in the same filesystem, otherwise an OSError is raised with errno set to errno.EXDEV.

This copy is done without the additional cost of transferring data from the kernel to user space and then back into the kernel. Additionally, some filesystems could implement extra optimizations, such as the use of reflinks (i.e., two or more inodes that share pointers to the same copy-on-write disk blocks; supported file systems include btrfs and XFS) and server-side copy (in the case of NFS).

The function copies bytes between two file descriptors. Text options, like the encoding and the line ending, are ignored.

반환 값은 복사된 바이트의 양입니다. 이것은 요구된 양보다 적을 수 있습니다.

참고

On Linux, os.copy_file_range() should not be used for copying a range of a pseudo file from a special filesystem like procfs and sysfs. It will always copy no bytes and return 0 as if the file was empty because of a known Linux kernel issue.

Availability: Linux >= 4.5 with glibc >= 2.27.

Added in version 3.8.

os.device_encoding(fd)

fd 와 연관된 장치가 터미널에 연결되어 있을 때 인코딩을 설명하는 문자열을 반환합니다; 그렇지 않으면 None을 반환합니다.

On Unix, if the Python UTF-8 Mode is enabled, return 'UTF-8' rather than the device encoding.

버전 3.10에서 변경: On Unix, the function now implements the Python UTF-8 Mode.

os.dup(fd, /)

파일 기술자 fd 의 복사본을 반환합니다. 새 파일 기술자는 상속 불가능합니다.

윈도우에서는, 표준 스트림(0: stdin, 1: stdout, 2: stderr)을 복제할 때, 새 파일 기술자가 상속 가능합니다.

Availability: not WASI.

버전 3.4에서 변경: 새로운 파일 기술자는 이제 상속 불가능합니다.

os.dup2(fd, fd2, inheritable=True)

파일 기술자 fd 를 fd2에 복제하고, 필요하면 먼저 후자를 닫습니다. fd2를 반환합니다. 새로운 파일 기술자는 기본적으로 상속 가능하고, inheritable 이 False면 상속 불가능합니다.

Availability: not WASI.

버전 3.4에서 변경: 선택적 inheritable 매개 변수를 추가했습니다.

버전 3.7에서 변경: 성공하면 fd2 를 반환합니다. 이전에는 항상 None을 반환했습니다.

os.fchmod(fd, mode)

fd 에 의해 주어진 파일의 모드를 숫자 mode 로 변경합니다. mode의 가능한 값은 chmod() 문서를 참조하십시오. 파이썬 3.3부터는, os.chmod(fd, mode)와 같습니다.

path, mode, dir_fd를 인자로 감사 이벤트(auditing event) os.chmod를 발생시킵니다.

Availability: Unix, Windows.

The function is limited on WASI, see WebAssembly platforms for more information.

버전 3.13에서 변경: Added support on Windows.

os.fchown(fd, uid, gid)

fd 에 의해 주어진 파일의 소유자와 그룹 id를 숫자 uid 와 gid로 변경합니다. ID 중 하나를 변경하지 않으려면, 그것을 -1로 설정하십시오. chown()를 참조하십시오. 파이썬 3.3부터는, os.chown(fd, uid, gid)와 같습니다.

path, uid, gid, dir_fd를 인자로 감사 이벤트(auditing event) os.chown을 발생시킵니다.

Availability: Unix.

The function is limited on WASI, see WebAssembly platforms for more information.

os.fdatasync(fd)

파일 기술자 fd 로 주어진 파일을 디스크에 쓰도록 강제합니다. 메타 데이터를 갱신하도록 강제하지 않습니다.

Availability: Unix.

참고

이 함수는 MacOS에서는 사용할 수 없습니다.

os.fpathconf(fd, name, /)

열린 파일과 관련된 시스템 구성 정보를 반환합니다. name 은 조회할 구성 값을 지정합니다; 정의된 시스템 값의 이름인 문자열일 수 있습니다; 이 이름은 여러 표준(POSIX.1, 유닉스 95, 유닉스 98 및 기타)에서 지정됩니다. 일부 플랫폼은 추가 이름도 정의합니다. 호스트 운영 체제에 알려진 이름은 pathconf_names 딕셔너리에서 제공됩니다. 이 매핑에 포함되지 않은 구성 변수의 경우, name에 정수를 전달하는 것도 허용됩니다.

name 이 문자열이고 알 수 없으면, ValueError가 발생합니다. name에 대한 특정 값이 호스트 시스템에서 지원되지 않으면, pathconf_names에 포함되어 있어도, 에러 번호가 errno.EINVAL인 OSError가 발생합니다.

파이썬 3.3부터, os.pathconf(fd, name)과 같습니다.

Availability: Unix.

os.fstat(fd)

파일 기술자 fd 의 상태를 가져옵니다. stat_result 객체를 반환합니다.

파이썬 3.3부터는, os.stat(fd)와 같습니다.

더 보기

stat() 함수.

os.fstatvfs(fd, /)

statvfs() 처럼, 파일 기술자 fd 와 연관된 파일을 포함하는 파일 시스템에 대한 정보를 반환합니다. 파이썬 3.3부터는, os.statvfs(fd)와 같습니다.

Availability: Unix.

os.fsync(fd)

Force write of file with filedescriptor fd to disk. On Unix, this calls the native fsync() function; on Windows, the MS _commit() function.

버퍼링 된 파이썬 파일 객체 f로 시작하는 경우, f 와 연관된 모든 내부 버퍼가 디스크에 기록되게 하려면, 먼저 f.flush()를 수행한 다음 os.fsync(f.fileno())를 하십시오.

Availability: Unix, Windows.

os.ftruncate(fd, length, /)

파일 기술자 fd에 해당하는 파일을 잘라내어 최대 length 바이트가 되도록 만듭니다. 파이썬 3.3부터는, os.truncate(fd, length)와 같습니다.

fd, length를 인자로 감사 이벤트(auditing event) os.truncate를 발생시킵니다.

Availability: Unix, Windows.

버전 3.5에서 변경: 윈도우 지원 추가

os.get_blocking(fd, /)

파일 기술자의 블로킹 모드를 얻어옵니다: O_NONBLOCK 플래그가 설정되었으면 False, 플래그가 지워졌으면 True.

set_blocking() 및 socket.socket.setblocking()도 참조하십시오.

Availability: Unix, Windows.

The function is limited on WASI, see WebAssembly platforms for more information.

On Windows, this function is limited to pipes.

Added in version 3.5.

버전 3.12에서 변경: Added support for pipes on Windows.

os.grantpt(fd, /)

Grant access to the slave pseudo-terminal device associated with the master pseudo-terminal device to which the file descriptor fd refers. The file descriptor fd is not closed upon failure.

Calls the C standard library function grantpt().

Availability: Unix, not WASI.

Added in version 3.13.

os.isatty(fd, /)

파일 기술자 fd 가 열려 있고 tty(류의) 장치에 연결되어 있으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

os.lockf(fd, cmd, len, /)

열린 파일 기술자에 POSIX 록을 적용, 검사 또는 제거합니다. fd 는 열린 파일 기술자입니다. cmd 는 사용할 명령을 지정합니다 - F_LOCK, F_TLOCK, F_ULOCK 또는 F_TEST 중 하나. len 은 잠글 파일의 영역을 지정합니다.

fd, cmd, len을 인자로 감사 이벤트(auditing event) os.lockf를 발생시킵니다.

Availability: Unix.

Added in version 3.3.

os.F_LOCK

os.F_TLOCK

os.F_ULOCK

os.F_TEST

lockf()가 취할 조치를 지정하는 플래그.

Availability: Unix.

Added in version 3.3.

os.login_tty(fd, /)

Prepare the tty of which fd is a file descriptor for a new login session. Make the calling process a session leader; make the tty the controlling tty, the stdin, the stdout, and the stderr of the calling process; close fd.

Availability: Unix, not WASI.

Added in version 3.11.

os.lseek(fd, pos, whence, /)

Set the current position of file descriptor fd to position pos, modified by whence, and return the new position in bytes relative to the start of the file. Valid values for whence are:

SEEK_SET or 0 – set pos relative to the beginning of the file

SEEK_CUR or 1 – set pos relative to the current file position

SEEK_END or 2 – set pos relative to the end of the file

SEEK_HOLE – set pos to the next data location, relative to pos

SEEK_DATA – set pos to the next data hole, relative to pos

버전 3.3에서 변경: Add support for SEEK_HOLE and SEEK_DATA.

os.SEEK_SET

os.SEEK_CUR

os.SEEK_END

Parameters to the lseek() function and the seek() method on file-like objects, for whence to adjust the file position indicator.

SEEK_SET

Adjust the file position relative to the beginning of the file.

SEEK_CUR

Adjust the file position relative to the current file position.

SEEK_END

Adjust the file position relative to the end of the file.

Their values are 0, 1, and 2, respectively.

os.SEEK_HOLE

os.SEEK_DATA

Parameters to the lseek() function and the seek() method on file-like objects, for seeking file data and holes on sparsely allocated files.

SEEK_DATA

Adjust the file offset to the next location containing data, relative to the seek position.

SEEK_HOLE

Adjust the file offset to the next location containing a hole, relative to the seek position. A hole is defined as a sequence of zeros.

참고

These operations only make sense for filesystems that support them.

Availability: Linux >= 3.1, macOS, Unix

Added in version 3.3.

os.open(path, flags, mode=0o777, *, dir_fd=None)

파일 path를 열고 flags 에 따른 다양한 플래그와 때로 mode 따른 모드를 설정합니다. mode를 계산할 때, 현재 umask 값으로 먼저 마스킹합니다. 새롭게 열린 파일의 파일 기술자를 돌려줍니다. 새 파일 기술자는 상속 불가능합니다.

플래그와 모드 값에 대한 설명은, C 런타임 설명서를 참조하십시오; 플래그 상수(O_RDONLY 와 O_WRONLY와 같은)는 os 모듈에 정의되어 있습니다. 특히, 윈도우에서 바이너리 모드로 파일을 열려면 O_BINARY를 추가해야 합니다.

이 함수는 dir_fd 매개 변수로 디렉터리 기술자에 상대적인 경로를 지원할 수 있습니다.

path, mode, flags를 인자로 감사 이벤트(auditing event) open을 발생시킵니다.

버전 3.4에서 변경: 새로운 파일 기술자는 이제 상속 불가능합니다.

참고

이 함수는 저수준 I/O를 위한 것입니다. 일반적인 사용을 위해서는 내장 함수 open()을 사용하십시오, 이 함수는 read() 및 write() 메서드(와 더 많은 메서드)가있는 파일 객체를 반환합니다. 파일 기술자를 파일 객체로 싸려면, fdopen()을 사용하십시오.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 함수는 이제 InterruptedError 예외를 일으키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하세요).

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

다음 상수는 open() 함수에 대한 flags 매개 변수의 옵션입니다. 비트별 OR 연산자 |를 사용하여 결합할 수 있습니다. 일부는 모든 플랫폼에서 사용할 수는 없습니다. 가용성과 사용에 대한 설명은 유닉스의 open(2) [https://manpages.debian.org/open(2)] 매뉴얼 페이지 또는 윈도우의 MSDN [https://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx]을 참조하십시오.

os.O_RDONLY

os.O_WRONLY

os.O_RDWR

os.O_APPEND

os.O_CREAT

os.O_EXCL

os.O_TRUNC

위의 상수는 유닉스 및 윈도우에서 사용할 수 있습니다.

os.O_DSYNC

os.O_RSYNC

os.O_SYNC

os.O_NDELAY

os.O_NONBLOCK

os.O_NOCTTY

os.O_CLOEXEC

위의 상수는 유닉스에서만 사용할 수 있습니다.

버전 3.3에서 변경: O_CLOEXEC 상수를 추가합니다.

os.O_BINARY

os.O_NOINHERIT

os.O_SHORT_LIVED

os.O_TEMPORARY

os.O_RANDOM

os.O_SEQUENTIAL

os.O_TEXT

위의 상수는 윈도우에서만 사용할 수 있습니다.

os.O_EVTONLY

os.O_FSYNC

os.O_SYMLINK

os.O_NOFOLLOW_ANY

The above constants are only available on macOS.

버전 3.10에서 변경: Add O_EVTONLY, O_FSYNC, O_SYMLINK and O_NOFOLLOW_ANY constants.

os.O_ASYNC

os.O_DIRECT

os.O_DIRECTORY

os.O_NOFOLLOW

os.O_NOATIME

os.O_PATH

os.O_TMPFILE

os.O_SHLOCK

os.O_EXLOCK

위의 상수는 확장이며 C 라이브러리에서 정의하지 않으면 존재하지 않습니다.

버전 3.4에서 변경: 지원하는 시스템에 O_PATH를 추가합니다. 리눅스 커널 3.11 이상에서만 사용 가능한 O_TMPFILE를 추가합니다.

os.openpty()

새로운 의사 터미널 쌍을 엽니다. 파일 기술자의 쌍 (master, slave) 를 반환하는데, 각각 pty와 tty 입니다. 새 파일 기술자는 상속 불가능합니다. (약간) 더 이식성 있는 접근 방식을 사용하려면, pty 모듈을 사용하십시오.

Availability: Unix, not WASI.

버전 3.4에서 변경: 새로운 파일 기술자는 이제 상속 불가능합니다.

os.pipe()

파이프를 만듭니다. 파일 기술자 쌍 (r, w) 를 반환하는데, 각각 읽기와 쓰기에 사용할 수 있습니다. 새 파일 기술자는 상속 불가능합니다.

Availability: Unix, Windows.

버전 3.4에서 변경: 새로운 파일 기술자는 이제 상속 불가능합니다.

os.pipe2(flags, /)

flags 가 원자적으로 설정된 파이프를 만듭니다. flags 는 다음과 같은 값들을 하나 이상 OR 해서 만들 수 있습니다: O_NONBLOCK, O_CLOEXEC. 파일 기술자 쌍 (r, w) 를 반환하는데, 각각 읽기와 쓰기에 사용할 수 있습니다.

Availability: Unix, not WASI.

Added in version 3.3.

os.posix_fallocate(fd, offset, len, /)

fd로 지정된 파일이 offset 에서 시작하여 len 바이트 동안 계속되도록 충분한 디스크 공간을 할당합니다.

Availability: Unix.

Added in version 3.3.

os.posix_fadvise(fd, offset, len, advice, /)

특정 패턴으로 데이터에 액세스하려는 의도를 알려 커널이 최적화할 수 있도록 합니다. 조언(advice)은 fd에 의해 지정된 파일의 offset 에서 시작하여 len 바이트 동안 계속되는 영역에 적용됩니다. advice는 POSIX_FADV_NORMAL, POSIX_FADV_SEQUENTIAL, POSIX_FADV_RANDOM, POSIX_FADV_NOREUSE, POSIX_FADV_WILLNEED 또는 POSIX_FADV_DONTNEED 중 하나입니다.

Availability: Unix.

Added in version 3.3.

os.POSIX_FADV_NORMAL

os.POSIX_FADV_SEQUENTIAL

os.POSIX_FADV_RANDOM

os.POSIX_FADV_NOREUSE

os.POSIX_FADV_WILLNEED

os.POSIX_FADV_DONTNEED

사용 가능성이 큰 액세스 패턴을 지정하는 posix_fadvise()의 advice 에 사용될 수 있는 플래그.

Availability: Unix.

Added in version 3.3.

os.pread(fd, n, offset, /)

파일 기술자 fd에서 offset 의 위치부터 최대 n 바이트를 읽어 들이고, 파일 오프셋은 변경되지 않은 채로 남겨 둡니다.

읽어 들인 바이트를 포함하는 바이트열을 돌려줍니다. fd 에 의해 참조된 파일의 끝에 도달하면, 빈 바이트열 객체가 반환됩니다.

Availability: Unix.

Added in version 3.3.

os.posix_openpt(oflag, /)

Open and return a file descriptor for a master pseudo-terminal device.

Calls the C standard library function posix_openpt(). The oflag argument is used to set file status flags and file access modes as specified in the manual page of posix_openpt() of your system.

The returned file descriptor is non-inheritable. If the value O_CLOEXEC is available on the system, it is added to oflag.

Availability: Unix, not WASI.

Added in version 3.13.

os.preadv(fd, buffers, offset, flags=0, /)

파일 기술자 fd에서 offset 위치부터 가변 바이트열류 객체들 buffers 로 읽어 들이고, 파일 오프셋은 변경되지 않은 채로 남겨 둡니다. 데이터가 가득 찰 때까지 각 버퍼로 데이터를 전송한 다음 나머지 데이터를 보관하기 위해 시퀀스의 다음 버퍼로 이동합니다.

flags 인자는 다음 플래그 중 0개 이상의 비트별 OR를 포함합니다:

RWF_HIPRI

RWF_NOWAIT

실제로 읽힌 총 바이트 수를 반환합니다. 이 값은 모든 객체의 총 용량보다 작을 수 있습니다.

운영 체제는 사용할 수 있는 버퍼 수에 한계(sysconf() 값 'SC_IOV_MAX')를 설정할 수 있습니다.

os.readv() 와 os.pread()의 기능을 결합합니다.

Availability: Linux >= 2.6.30, FreeBSD >= 6.0, OpenBSD >= 2.7, AIX >= 7.1.

Using flags requires Linux >= 4.6.

Added in version 3.7.

os.RWF_NOWAIT

즉시 사용할 수 없는 데이터를 기다리지 않습니다. 이 플래그를 지정하면, 하부 저장 장치에서 데이터를 읽어야 하거나 록을 기다려야 할 때 즉시 시스템 호출이 반환됩니다.

If some data was successfully read, it will return the number of bytes read. If no bytes were read, it will return -1 and set errno to errno.EAGAIN.

Availability: Linux >= 4.14.

Added in version 3.7.

os.RWF_HIPRI

우선순위가 높은 읽기/쓰기. 블록 기반 파일 시스템이 장치의 폴링을 사용할 수 있게 하여, 지연은 짧아 지지만, 추가 자원을 사용할 수 있습니다.

현재, 리눅스에서, 이 기능은 O_DIRECT 플래그를 사용하여 열린 파일 기술자에만 사용할 수 있습니다.

Availability: Linux >= 4.6.

Added in version 3.7.

os.ptsname(fd, /)

Return the name of the slave pseudo-terminal device associated with the master pseudo-terminal device to which the file descriptor fd refers. The file descriptor fd is not closed upon failure.

Calls the reentrant C standard library function ptsname_r() if it is available; otherwise, the C standard library function ptsname(), which is not guaranteed to be thread-safe, is called.

Availability: Unix, not WASI.

Added in version 3.13.

os.pwrite(fd, str, offset, /)

파일 기술자 fd의 offset 위치에 str 바이트열을 쓰고, 파일 오프셋은 변경되지 않은 채로 남겨 둡니다.

실제로 쓴 바이트 수를 반환합니다.

Availability: Unix.

Added in version 3.3.

os.pwritev(fd, buffers, offset, flags=0, /)

Write the buffers contents to file descriptor fd at an offset offset, leaving the file offset unchanged. buffers must be a sequence of bytes-like objects. Buffers are processed in array order. Entire contents of the first buffer is written before proceeding to the second, and so on.

flags 인자는 다음 플래그 중 0개 이상의 비트별 OR를 포함합니다:

RWF_DSYNC

RWF_SYNC

RWF_APPEND

실제로 쓴 총 바이트 수를 반환합니다.

운영 체제는 사용할 수 있는 버퍼 수에 한계(sysconf() 값 'SC_IOV_MAX')를 설정할 수 있습니다.

os.writev() 와 os.pwrite()의 기능을 결합합니다.

Availability: Linux >= 2.6.30, FreeBSD >= 6.0, OpenBSD >= 2.7, AIX >= 7.1.

Using flags requires Linux >= 4.6.

Added in version 3.7.

os.RWF_DSYNC

Provide a per-write equivalent of the O_DSYNC os.open() flag. This flag effect applies only to the data range written by the system call.

Availability: Linux >= 4.7.

Added in version 3.7.

os.RWF_SYNC

Provide a per-write equivalent of the O_SYNC os.open() flag. This flag effect applies only to the data range written by the system call.

Availability: Linux >= 4.7.

Added in version 3.7.

os.RWF_APPEND

Provide a per-write equivalent of the O_APPEND os.open() flag. This flag is meaningful only for os.pwritev(), and its effect applies only to the data range written by the system call. The offset argument does not affect the write operation; the data is always appended to the end of the file. However, if the offset argument is -1, the current file offset is updated.

Availability: Linux >= 4.16.

Added in version 3.10.

os.read(fd, n, /)

파일 기술자 fd에서 최대 n 바이트를 읽습니다.

읽어 들인 바이트를 포함하는 바이트열을 돌려줍니다. fd 에 의해 참조된 파일의 끝에 도달하면, 빈 바이트열 객체가 반환됩니다.

참고

이 함수는 저수준 I/O를 위한 것이며 os.open() 이나 pipe()에 의해 반환된 파일 기술자에 적용되어야 합니다. 내장 함수 open() 이나 popen() 또는 fdopen()에 의해 반환된 “파일 객체”나 sys.stdin을 읽으려면, 그것의 read() 나 readline() 메서드를 사용하십시오.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 함수는 이제 InterruptedError 예외를 일으키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하세요).

os.sendfile(out_fd, in_fd, offset, count)

os.sendfile(out_fd, in_fd, offset, count, headers=(), trailers=(), flags=0)

파일 기술자 in_fd에서 파일 기술자 out_fd 로 offset에서 시작하여 count 바이트를 복사합니다. 전송된 바이트 수를 반환합니다. EOF에 도달하면 0을 반환합니다.

첫 번째 함수 서명은 sendfile()를 정의하는 모든 플랫폼에서 지원됩니다.

리눅스에서, offset이 None으로 주어지면, in_fd의 현재 위치에서 바이트를 읽고 in_fd의 위치가 갱신됩니다.

The second case may be used on macOS and FreeBSD where headers and trailers are arbitrary sequences of buffers that are written before and after the data from in_fd is written. It returns the same as the first case.

On macOS and FreeBSD, a value of 0 for count specifies to send until the end of in_fd is reached.

모든 플랫폼은 out_fd 파일 기술자로 소켓을 지원하고, 일부 플랫폼은 다른 유형(예를 들어 일반 파일, 파이프)들도 허락합니다.

이기종 플랫폼 응용 프로그램은 headers, trailers 및 flags 인자를 사용해서는 안 됩니다.

Availability: Unix, not WASI.

참고

sendfile()의 고수준 래퍼는, socket.socket.sendfile()을 보십시오.

Added in version 3.3.

버전 3.9에서 변경: 매개 변수 out과 in의 이름이 out_fd와 in_fd로 변경되었습니다.

os.SF_NODISKIO

os.SF_MNOWAIT

os.SF_SYNC

구현이 지원하는 경우, sendfile() 함수에 대한 매개 변수입니다.

Availability: Unix, not WASI.

Added in version 3.3.

os.SF_NOCACHE

Parameter to the sendfile() function, if the implementation supports it. The data won’t be cached in the virtual memory and will be freed afterwards.

Availability: Unix, not WASI.

Added in version 3.11.

os.set_blocking(fd, blocking, /)

지정된 파일 기술자의 블로킹 모드를 설정합니다. blocking이 False면 O_NONBLOCK 플래그를 설정하고, 그렇지 않으면 플래그를 지웁니다.

get_blocking()과 socket.socket.setblocking()도 참조하십시오.

Availability: Unix, Windows.

The function is limited on WASI, see WebAssembly platforms for more information.

On Windows, this function is limited to pipes.

Added in version 3.5.

버전 3.12에서 변경: Added support for pipes on Windows.

os.splice(src, dst, count, offset_src=None, offset_dst=None, flags=0)

Transfer count bytes from file descriptor src, starting from offset offset_src, to file descriptor dst, starting from offset offset_dst.

The splicing behaviour can be modified by specifying a flags value. Any of the following variables may used, combined using bitwise OR (the | operator):

If SPLICE_F_MOVE is specified, the kernel is asked to move pages instead of copying, but pages may still be copied if the kernel cannot move the pages from the pipe.

If SPLICE_F_NONBLOCK is specified, the kernel is asked to not block on I/O. This makes the splice pipe operations nonblocking, but splice may nevertheless block because the spliced file descriptors may block.

If SPLICE_F_MORE is specified, it hints to the kernel that more data will be coming in a subsequent splice.

At least one of the file descriptors must refer to a pipe. If offset_src is None, then src is read from the current position; respectively for offset_dst. The offset associated to the file descriptor that refers to a pipe must be None. The files pointed to by src and dst must reside in the same filesystem, otherwise an OSError is raised with errno set to errno.EXDEV.

이 복사는 커널에서 사용자 공간으로 데이터를 전송한 다음 다시 커널로 전송하는 추가 비용 없이 수행됩니다. 또한, 일부 파일 시스템은 추가 최적화를 구현할 수 있습니다. 두 파일이 바이너리로 열린 것처럼 복사가 수행됩니다.

Upon successful completion, returns the number of bytes spliced to or from the pipe. A return value of 0 means end of input. If src refers to a pipe, then this means that there was no data to transfer, and it would not make sense to block because there are no writers connected to the write end of the pipe.

더 보기

The splice(2) [https://manpages.debian.org/splice(2)] man page.

Availability: Linux >= 2.6.17 with glibc >= 2.5

Added in version 3.10.

os.SPLICE_F_MOVE

os.SPLICE_F_NONBLOCK

os.SPLICE_F_MORE

Added in version 3.10.

os.readv(fd, buffers, /)

파일 기술자 fd에서 여러 가변 바이트열류 객체 buffers로 읽어 들입니다. 데이터가 가득 찰 때까지 각 버퍼로 데이터를 전송한 다음 나머지 데이터를 보관하기 위해 시퀀스의 다음 버퍼로 이동합니다.

실제로 읽힌 총 바이트 수를 반환합니다. 이 값은 모든 객체의 총 용량보다 작을 수 있습니다.

운영 체제는 사용할 수 있는 버퍼 수에 한계(sysconf() 값 'SC_IOV_MAX')를 설정할 수 있습니다.

Availability: Unix.

Added in version 3.3.

os.tcgetpgrp(fd, /)

fd(os.open()에 의해 반환된 것과 같은 열린 파일 기술자)에 의해 주어진 터미널과 관련된 프로세스 그룹을 반환합니다.

Availability: Unix, not WASI.

os.tcsetpgrp(fd, pg, /)

fd(os.open()에 의해 반환된 것과 같은 열린 파일 기술자)에 의해 주어진 터미널과 관련된 프로세스 그룹을 pg로 설정합니다.

Availability: Unix, not WASI.

os.ttyname(fd, /)

파일 기술자 fd와 관련된 터미널 장치를 나타내는 문자열을 돌려줍니다. fd 가 터미널 장치와 연관되어 있지 않으면, 예외가 발생합니다.

Availability: Unix.

os.unlockpt(fd, /)

Unlock the slave pseudo-terminal device associated with the master pseudo-terminal device to which the file descriptor fd refers. The file descriptor fd is not closed upon failure.

Calls the C standard library function unlockpt().

Availability: Unix, not WASI.

Added in version 3.13.

os.write(fd, str, /)

str 바이트열을 파일 기술자 fd 에 씁니다.

실제로 쓴 바이트 수를 반환합니다.

참고

이 함수는 저수준 I/O를 위한 것이며 os.open() 이나 pipe()에 의해 반환된 파일 기술자에 적용되어야 합니다. 내장 함수 open() 이나 popen() 또는 fdopen()에 의해 반환된 “파일 객체”나 sys.stdout 또는 sys.stderr에 쓰려면, 그것의 write() 메서드를 사용하십시오.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 함수는 이제 InterruptedError 예외를 일으키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하세요).

os.writev(fd, buffers, /)

buffers 내용을 파일 기술자 fd에 씁니다. buffers 는 바이트열류 객체의 시퀀스 여야 합니다. 버퍼는 배열 순서로 처리됩니다. 첫 번째 버퍼의 전체 내용은 두 번째 버퍼로 진행하기 전에 기록되고, 같은 식으로 계속 진행합니다.

실제로 쓴 총 바이트 수를 반환합니다.

운영 체제는 사용할 수 있는 버퍼 수에 한계(sysconf() 값 'SC_IOV_MAX')를 설정할 수 있습니다.

Availability: Unix.

Added in version 3.3.

터미널의 크기 조회하기

Added in version 3.3.

os.get_terminal_size(fd=STDOUT_FILENO, /)

터미널 창의 크기를 (columns, lines) 로 반환하는데, terminal_size 형의 튜플입니다.

선택적 인자 fd(기본값 STDOUT_FILENO, 즉 표준 출력)는 조회할 파일 기술자를 지정합니다.

파일 기술자가 터미널에 연결되어 있지 않으면, OSError가 발생합니다.

shutil.get_terminal_size()가 일반적으로 사용해야 하는 고수준 함수이며, os.get_terminal_size는 저수준 구현입니다.

Availability: Unix, Windows.

class os.terminal_size

터미널 창 크기 (columns, lines)를 저장하는 튜플의 서브 클래스.

columns

문자 단위의 터미널 창의 너비.

lines

문자 단위의 터미널 창의 높이.

파일 기술자의 상속

Added in version 3.4.

파일 기술자는 자식 프로세스가 파일 기술자를 상속받을 수 있는지를 나타내는 “상속 가능” 플래그를 가지고 있습니다. 파이썬 3.4부터, 파이썬에 의해 생성된 파일 기술자는 기본적으로 상속 불가능합니다.

유닉스에서는, 상속 불가능한 파일 기술자는 새 프로그램 실행 시 자식 프로세스에서 닫히고, 다른 파일 기술자는 상속됩니다.

윈도우에서는, 항상 상속되는 표준 스트림(파일 기술자 0, 1, 2: stdin, stdout, stderr)을 제외하고, 상속 불가능한 핸들 및 파일 기술자는 자식 프로세스에서 닫힙니다. spawn* 함수를 사용하면, 상속 가능한 모든 핸들과 상속 가능한 모든 파일 기술자가 상속됩니다. subprocess 모듈을 사용하면, 표준 스트림을 제외한 모든 파일 기술자가 닫히고, 상속 가능한 핸들은 close_fds 매개 변수가 False 일 때만 상속됩니다.

On WebAssembly platforms, the file descriptor cannot be modified.

os.get_inheritable(fd, /)

지정된 파일 기술자의 “상속 가능” 플래그를 가져옵니다 (논릿값).

os.set_inheritable(fd, inheritable, /)

지정된 파일 기술자의 “상속 가능(inheritable)” 플래그를 설정합니다.

os.get_handle_inheritable(handle, /)

지정된 핸들의 “상속 가능” 플래그를 가져옵니다 (논릿값).

Availability: Windows.

os.set_handle_inheritable(handle, inheritable, /)

지정된 핸들의 “상속 가능(inheritable)” 플래그를 설정합니다.

Availability: Windows.

파일과 디렉터리

일부 유닉스 플랫폼에서, 이 함수 중 많은 것들이 다음 기능 중 하나 이상을 지원합니다:

파일 기술자 지정: 일반적으로 os 모듈에 있는 함수에 제공되는 path 인자는 파일 경로를 지정하는 문자열이어야 합니다. 하지만, 일부 함수는 이제 path 인자로 열린 파일 기술자를 대신 받아들입니다. 그러면 그 함수는 기술자가 참조하는 파일에서 작동합니다. (POSIX 시스템에서, 파이썬은 함수의 f 접두어가 붙은 함수의 변종을 호출합니다 (예를 들어, chdir 대신 fchdir).)

os.supports_fd를 사용하여, 여러분의 플랫폼에서 특정 함수에 파일 기술자로 path를 지정할 수 있는지를 확인할 수 있습니다. 사용할 수 없을 때, 사용하면 NotImplementedError를 발생시킵니다.

함수가 dir_fd 나 follow_symlinks 인자도 지원하면, path 에 파일 기술자를 제공할 때, 이 중 하나를 지정하는 것은 에러입니다.

디렉터리 기술자에 상대적인 경로: dir_fd 가 None이 아니면, 디렉터리를 가리키는 파일 기술자여야 하며, 대상 경로는 상대 경로여야 합니다; 그러면 경로는 그 디렉터리에 상대적입니다. 절대 경로이면, dir_fd 는 무시됩니다. (POSIX 시스템에서, 파이썬은 at 접미사를 붙이거나 어쩌면 f 접두사도 붙인 함수의 변종을 호출합니다. 예를 들어, access 대신 faccessat를 호출합니다)

os.supports_dir_fd를 사용하여, 여러분의 플랫폼에서 특정 함수에 dir_fd가 지원되는지를 확인할 수 있습니다. 사용할 수 없을 때, 사용하면 NotImplementedError를 발생시킵니다.

심볼릭 링크를 따르지 않음: follow_symlinks 가 False고, 대상 경로의 마지막 요소가 심볼릭 링크면, 함수는 링크가 가리키는 파일 대신 심볼릭 링크 자체에 대해 작동합니다. (POSIX 시스템에서, 파이썬은 함수의 l... 변종을 호출합니다.)

os.supports_follow_symlinks를 사용하여, 여러분의 플랫폼에서 특정 함수에 follow_symlinks가 지원되는지를 확인할 수 있습니다. 사용할 수 없을 때, 사용하면 NotImplementedError를 발생시킵니다.

os.access(path, mode, *, dir_fd=None, effective_ids=False, follow_symlinks=True)

실제(real) uid/gid를 사용해서 path를 액세스할 수 있는지 검사합니다. 대부분의 연산은 유효한(effective) uid/gid를 사용할 것이므로, 이 함수는 suid/sgid 환경에서 호출하는 사용자가 지정된 path 에 대한 액세스 권한이 있는지 검사하는데 사용할 수 있습니다. path가 존재하는지를 검사하려면 mode 는 F_OK 여야 하며, 권한을 검사하려면 하나 이상의 R_OK, W_OK 및 X_OK를 OR 값일 수 있습니다. 액세스가 허용되면 True를 반환하고, 그렇지 않으면 False를 반환합니다. 더 자세한 정보는 유닉스 매뉴얼 페이지 access(2) [https://manpages.debian.org/access(2)]를 참조하십시오.

이 함수는 디렉터리 기술자에 상대적인 경로 와 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

effective_ids 가 True면, access()는 실제(real) uid/gid 대신 유효한(effective) uid/gid를 사용하여 액세스 검사를 수행합니다. effective_ids 는 플랫폼에서 지원되지 않을 수 있습니다; os.supports_effective_ids를 사용하여, 사용할 수 있는지를 확인할 수 있습니다. 사용할 수 없을 때, 사용하면 NotImplementedError를 발생시킵니다.

참고

예를 들어, 실제로 open()를 사용하여 파일을 열기 전에, access()를 사용하여 파일을 여는 권한이 있는지 확인하는 것은 보안 구멍을 만듭니다. 사용자가 파일을 확인하고 조작을 위해 열기 사이의 짧은 시간 간격을 악용할 수 있기 때문입니다. EAFP 기법을 사용하는 것이 좋습니다. 예를 들면:

if os.access("myfile", os.R_OK):
    with open("myfile") as fp:
        return fp.read()
return "some default data"

는 다음과 같이 쓰는 것이 더 좋습니다:

try:
    fp = open("myfile")
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read()

참고

access()가 성공할 것임을 알릴 때도, I/O 연산이 실패할 수 있습니다. 특히 일반적인 POSIX 권한 비트 모델을 넘어서는 권한 의미가 있을 수 있는 네트워크 파일 시스템에 대한 연산에서 그럴 수 있습니다.

버전 3.3에서 변경: dir_fd, effective_ids 및 follow_symlinks 매개 변수를 추가했습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.F_OK

os.R_OK

os.W_OK

os.X_OK

path 의 존재 여부, 읽기 가능성, 쓰기 가능성 및 실행 가능성을 검사하기 위해, access()의 mode 매개 변수로 전달할 값입니다.

os.chdir(path)

현재 작업 디렉터리를 path로 변경합니다.

이 함수는 파일 기술자 지정을 지원할 수 있습니다. 기술자는 열려있는 파일이 아니라, 열려있는 디렉터리를 참조해야 합니다.

이 함수는 OSError와 FileNotFoundError, PermissionError 및 NotADirectoryError와 같은 서브 클래스를 발생시킬 수 있습니다.

path를 인자로 감사 이벤트(auditing event) os.chdir을 발생시킵니다.

버전 3.3에서 변경: 일부 플랫폼에서 path 를 파일 기술자로 지정하는 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.chflags(path, flags, *, follow_symlinks=True)

path 의 플래그를 숫자 flags로 설정합니다. flags는 다음 값들(stat 모듈에 정의된 대로)의 조합(비트별 OR)을 취할 수 있습니다:

stat.UF_NODUMP

stat.UF_IMMUTABLE

stat.UF_APPEND

stat.UF_OPAQUE

stat.UF_NOUNLINK

stat.UF_COMPRESSED

stat.UF_HIDDEN

stat.SF_ARCHIVED

stat.SF_IMMUTABLE

stat.SF_APPEND

stat.SF_NOUNLINK

stat.SF_SNAPSHOT

이 함수는 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

path, flags를 인자로 감사 이벤트(auditing event) os.chflags를 발생시킵니다.

Availability: Unix, not WASI.

버전 3.3에서 변경: Added the follow_symlinks parameter.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.chmod(path, mode, *, dir_fd=None, follow_symlinks=True)

path의 모드를 숫자 mode로 변경합니다. mode 는 다음 값들(stat 모듈에 정의된 대로)이나 이들의 비트별 OR 조합을 취할 수 있습니다:

stat.S_ISUID

stat.S_ISGID

stat.S_ENFMT

stat.S_ISVTX

stat.S_IREAD

stat.S_IWRITE

stat.S_IEXEC

stat.S_IRWXU

stat.S_IRUSR

stat.S_IWUSR

stat.S_IXUSR

stat.S_IRWXG

stat.S_IRGRP

stat.S_IWGRP

stat.S_IXGRP

stat.S_IRWXO

stat.S_IROTH

stat.S_IWOTH

stat.S_IXOTH

이 함수는 파일 기술자 지정, 디렉터리 기술자에 상대적인 경로 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

참고

Although Windows supports chmod(), you can only set the file’s read-only flag with it (via the stat.S_IWRITE and stat.S_IREAD constants or a corresponding integer value). All other bits are ignored. The default value of follow_symlinks is False on Windows.

The function is limited on WASI, see WebAssembly platforms for more information.

path, mode, dir_fd를 인자로 감사 이벤트(auditing event) os.chmod를 발생시킵니다.

버전 3.3에서 변경: path를 열린 파일 기술자로 지정하는 지원과 dir_fd 및 follow_symlinks 인자가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.13에서 변경: Added support for a file descriptor and the follow_symlinks argument on Windows.

os.chown(path, uid, gid, *, dir_fd=None, follow_symlinks=True)

path 의 소유자와 그룹 ID를 숫자 uid 와 gid로 변경합니다. ID 중 하나를 변경하지 않으려면, 그것을 -1로 설정하십시오.

이 함수는 파일 기술자 지정, 디렉터리 기술자에 상대적인 경로 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

숫자 ID 이외에 이름을 허용하는 고수준 함수는 shutil.chown()를 참조하십시오.

path, uid, gid, dir_fd를 인자로 감사 이벤트(auditing event) os.chown을 발생시킵니다.

Availability: Unix.

The function is limited on WASI, see WebAssembly platforms for more information.

버전 3.3에서 변경: path를 열린 파일 기술자로 지정하는 지원과 dir_fd 및 follow_symlinks 인자가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 지원합니다.

os.chroot(path)

현재 프로세스의 루트 디렉터리를 path로 변경합니다.

Availability: Unix, not WASI, not Android.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.fchdir(fd)

현재 작업 디렉터리를 파일 기술자 fd가 나타내는 디렉터리로 변경합니다. 기술자는 열려있는 파일이 아니라 열려있는 디렉터리를 참조해야 합니다. 파이썬 3.3부터는, os.chdir(fd)와 같습니다.

path를 인자로 감사 이벤트(auditing event) os.chdir을 발생시킵니다.

Availability: Unix.

os.getcwd()

현재 작업 디렉터리를 나타내는 문자열을 반환합니다.

os.getcwdb()

현재 작업 디렉터리를 나타내는 바이트열을 반환합니다.

버전 3.8에서 변경: 이 함수는 이제 윈도우에서 ANSI 코드 페이지가 아닌 UTF-8 인코딩을 사용합니다: 이유는 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오. 이 함수는 윈도우에서 더는 폐지되지 않습니다.

os.lchflags(path, flags)

path 의 플래그를, chflags() 처럼, 숫자 flags로 설정하지만, 심볼릭 링크를 따르지 않습니다. 파이썬 3.3부터는, os.chflags(path, flags, follow_symlinks=False)와 같습니다.

path, flags를 인자로 감사 이벤트(auditing event) os.chflags를 발생시킵니다.

Availability: Unix, not WASI.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.lchmod(path, mode)

path 모드를 숫자 mode로 변경합니다. path가 심볼릭 링크면, 이 함수는 타깃이 아닌 심볼릭 링크에 영향을 미칩니다. mode의 가능한 값은 chmod() 문서를 참조하십시오. 파이썬 3.3부터는, os.chmod(path, mode, follow_symlinks=False)와 같습니다.

lchmod() is not part of POSIX, but Unix implementations may have it if changing the mode of symbolic links is supported.

path, mode, dir_fd를 인자로 감사 이벤트(auditing event) os.chmod를 발생시킵니다.

Availability: Unix, Windows, not Linux, FreeBSD >= 1.3, NetBSD >= 1.3, not OpenBSD

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.13에서 변경: Added support on Windows.

os.lchown(path, uid, gid)

path 의 소유자와 그룹 ID를 숫자 uid 와 gid로 변경합니다. 이 함수는 심볼릭 링크를 따르지 않습니다. 파이썬 3.3부터는, os.chown(path, uid, gid, follow_symlinks=False)와 같습니다.

path, uid, gid, dir_fd를 인자로 감사 이벤트(auditing event) os.chown을 발생시킵니다.

Availability: Unix.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.link(src, dst, *, src_dir_fd=None, dst_dir_fd=None, follow_symlinks=True)

src를 가리키는 dst 라는 이름의 하드 링크를 만듭니다.

이 함수는 디렉터리 기술자에 상대적인 경로를 제공하기 위해 src_dir_fd 와/나 dst_dir_fd 를 지정하는 것과, 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

src, dst, src_dir_fd, dst_dir_fd를 인자로 감사 이벤트(auditing event) os.link를 발생시킵니다.

Availability: Unix, Windows.

버전 3.2에서 변경: 윈도우 지원이 추가되었습니다.

버전 3.3에서 변경: Added the src_dir_fd, dst_dir_fd, and follow_symlinks parameters.

버전 3.6에서 변경: src 및 dst로 경로류 객체를 받아들입니다.

os.listdir(path='.')

path에 의해 주어진 디렉터리에 있는 항목들의 이름을 담고 있는 리스트를 반환합니다. 리스트는 임의의 순서로 나열되며, 디렉터리에 존재하더라도 특수 항목 '.' 과 '..'는 포함하지 않습니다. 이 함수 호출 중에 디렉터리에서 파일이 제거되거나 추가되면, 해당 파일의 이름이 포함되는지는 지정되지 않습니다.

path는 경로류 객체 일 수 있습니다. path 가 bytes 형이면 (직접 또는 PathLike 인터페이스를 통해 간접적으로), 반환되는 파일명도 bytes 형입니다; 다른 모든 상황에서는 형 str이 됩니다.

이 함수는 또한 파일 기술자 지정을 지원할 수 있습니다; 파일 기술자는 디렉터리를 참조해야 합니다.

path를 인자로 감사 이벤트(auditing event) os.listdir을 발생시킵니다.

참고

str 파일명을 bytes로 인코딩하려면, fsencode()를 사용하십시오.

더 보기

scandir() 함수는 파일 어트리뷰트 정보와 함께 디렉터리 항목을 반환하므로, 많은 일반적인 사용 사례에서 더 나은 성능을 제공합니다.

버전 3.2에서 변경: path 매개 변수는 선택 사항이 되었습니다.

버전 3.3에서 변경: path에 열린 파일 기술자를 지정하는 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.listdrives()

Return a list containing the names of drives on a Windows system.

A drive name typically looks like 'C:\\'. Not every drive name will be associated with a volume, and some may be inaccessible for a variety of reasons, including permissions, network connectivity or missing media. This function does not test for access.

May raise OSError if an error occurs collecting the drive names.

Raises an auditing event os.listdrives with no arguments.

Availability: Windows

Added in version 3.12.

os.listmounts(volume)

Return a list containing the mount points for a volume on a Windows system.

volume must be represented as a GUID path, like those returned by os.listvolumes(). Volumes may be mounted in multiple locations or not at all. In the latter case, the list will be empty. Mount points that are not associated with a volume will not be returned by this function.

The mount points return by this function will be absolute paths, and may be longer than the drive name.

Raises OSError if the volume is not recognized or if an error occurs collecting the paths.

Raises an auditing event os.listmounts with argument volume.

Availability: Windows

Added in version 3.12.

os.listvolumes()

Return a list containing the volumes in the system.

Volumes are typically represented as a GUID path that looks like \\?\Volume{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}\. Files can usually be accessed through a GUID path, permissions allowing. However, users are generally not familiar with them, and so the recommended use of this function is to retrieve mount points using os.listmounts().

May raise OSError if an error occurs collecting the volumes.

Raises an auditing event os.listvolumes with no arguments.

Availability: Windows

Added in version 3.12.

os.lstat(path, *, dir_fd=None)

Perform the equivalent of an lstat() system call on the given path. Similar to stat(), but does not follow symbolic links. Return a stat_result object.

심볼릭 링크를 지원하지 않는 플랫폼에서, 이 함수는 stat()의 별칭입니다.

파이썬 3.3부터는, os.stat(path, dir_fd=dir_fd, follow_symlinks=False)와 같습니다.

이 기능은 디렉터리 기술자에 상대적인 경로도 지원할 수 있습니다.

더 보기

stat() 함수.

버전 3.2에서 변경: 윈도우 6.0 (Vista) 심볼릭 링크에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서, 이제 심볼릭 링크와 디렉터리 정션(directory junction)을 포함하는 다른 경로를 나타내는 재해석 지점(reparse point, 이름 서로게이트)을 엽니다. 다른 유형의 재해석 지점은 운영 체제에서 stat()에서 처럼 결정됩니다.

os.mkdir(path, mode=0o777, *, dir_fd=None)

숫자 모드 mode로 path 라는 디렉터리를 만듭니다.

If the directory already exists, FileExistsError is raised. If a parent directory in the path does not exist, FileNotFoundError is raised.

일부 시스템에서는, mode가 무시됩니다. 모드가 사용될 때, 현재 umask 값으로 먼저 마스킹합니다. 마지막 9비트 (즉, mode 의 8진 표현의 마지막 3자리 수) 이외의 비트가 설정되면, 그 의미는 플랫폼에 따라 다릅니다. 일부 플랫폼에서는, 이것들이 무시되며, 설정하려면 명시적으로 chmod()를 호출해야 합니다.

On Windows, a mode of 0o700 is specifically handled to apply access control to the new directory such that only the current user and administrators have access. Other values of mode are ignored.

이 기능은 디렉터리 기술자에 상대적인 경로도 지원할 수 있습니다.

임시 디렉터리를 만들 수도 있습니다; tempfile 모듈의 tempfile.mkdtemp() 함수를 참조하십시오.

path, mode, dir_fd를 인자로 감사 이벤트(auditing event) os.mkdir을 발생시킵니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.13에서 변경: Windows now handles a mode of 0o700.

os.makedirs(name, mode=0o777, exist_ok=False)

재귀적 디렉터리 생성 함수. mkdir()와 비슷하지만, 말단 디렉터리를 포함하는 데 필요한 모든 중간 수준 디렉터리들을 만듭니다.

The mode parameter is passed to mkdir() for creating the leaf directory; see the mkdir() description for how it is interpreted. To set the file permission bits of any newly created parent directories you can set the umask before invoking makedirs(). The file permission bits of existing parent directories are not changed.

If exist_ok is False (the default), a FileExistsError is raised if the target directory already exists.

참고

makedirs()는 생성할 경로 요소에 pardir(예를 들어, 유닉스 시스템의 경우 “..”)이 포함되어 있으면 혼란해 할 수 있습니다.

이 함수는 UNC 경로를 올바르게 처리합니다.

path, mode, dir_fd를 인자로 감사 이벤트(auditing event) os.mkdir을 발생시킵니다.

버전 3.2에서 변경: Added the exist_ok parameter.

버전 3.4.1에서 변경: 파이썬 3.4.1 이전에는, exist_ok 가 True이고 디렉터리가 존재한다면, mode 가 기존 디렉터리의 모드와 일치하지 않을 때, makedirs()는 여전히 에러를 발생시킵니다. 이 동작은 안전하게 구현할 수 없으므로, 파이썬 3.4.1에서 제거되었습니다. bpo-21082 [https://bugs.python.org/issue?@action=redirect&bpo=21082]를 참조하십시오.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.7에서 변경: The mode argument no longer affects the file permission bits of newly created intermediate-level directories.

os.mkfifo(path, mode=0o666, *, dir_fd=None)

숫자 모드 mode로 path 라는 이름의 FIFO(이름있는 파이프)를 만듭니다. 현재 umask 값으로 먼저 모드를 마스킹합니다.

이 기능은 디렉터리 기술자에 상대적인 경로도 지원할 수 있습니다.

FIFO는 일반 파일처럼 액세스할 수 있는 파이프입니다. FIFO는 삭제될 때까지 존재합니다 (예를 들어 os.unlink()로). 일반적으로, FIFO는 “클라이언트”와 “서버” 유형 프로세스 사이에서 랑데부로 사용됩니다: 서버는 FIFO를 읽기 용도로 열고, 클라이언트는 쓰기 용도로 엽니다. mkfifo()가 FIFO를 열지는 않는다는 점에 유의하십시오 — 단지 랑데부 포인트를 생성합니다.

Availability: Unix, not WASI.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.mknod(path, mode=0o600, device=0, *, dir_fd=None)

path 라는 이름의 파일 시스템 노드(파일, 장치 특수 파일 또는 이름있는 파이프)를 만듭니다. mode 는 사용 권한과 생성될 노드의 유형을 모두 지정하며, stat.S_IFREG, stat.S_IFCHR, stat.S_IFBLK 및 stat.S_IFIFO 중 하나와 결합(비트별 OR)합니다 (이 상수들은 stat에 있습니다). stat.S_IFCHR와 stat.S_IFBLK의 경우, device 는 새로 만들어지는 장치 특수 파일(아마도 os.makedev()를 사용해서)을 정의합니다, 그렇지 않으면 무시됩니다.

이 기능은 디렉터리 기술자에 상대적인 경로도 지원할 수 있습니다.

Availability: Unix, not WASI.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.major(device, /)

Extract the device major number from a raw device number (usually the st_dev or st_rdev field from stat).

os.minor(device, /)

Extract the device minor number from a raw device number (usually the st_dev or st_rdev field from stat).

os.makedev(major, minor, /)

주 장치 번호와 부 장치 번호로 원시 장치 번호를 조립합니다.

os.pathconf(path, name)

이름있는 파일과 관련된 시스템 구성 정보를 반환합니다. name 은 조회할 구성 값을 지정합니다; 정의된 시스템 값의 이름인 문자열일 수 있습니다; 이 이름은 여러 표준(POSIX.1, 유닉스 95, 유닉스 98 및 기타)에서 지정됩니다. 일부 플랫폼은 추가적인 이름도 정의합니다. 호스트 운영 체제에 알려진 이름은 pathconf_names 딕셔너리에서 제공됩니다. 이 매핑에 포함되지 않은 구성 변수를 위해, name에 정수를 전달하는 것도 허용됩니다.

name 이 문자열이고 알 수 없으면, ValueError가 발생합니다. name에 대한 특정 값이 호스트 시스템에서 지원되지 않으면, pathconf_names에 포함되어 있어도, 에러 번호가 errno.EINVAL인 OSError가 발생합니다.

이 함수는 파일 기술자 지정을 지원할 수 있습니다.

Availability: Unix.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.pathconf_names

pathconf()와 fpathconf()가 받아들이는 이름을 호스트 운영 체제에서 해당 이름에 대해 정의된 정숫값으로 매핑하는 딕셔너리. 이것은 시스템에 알려진 이름 집합을 판별하는 데 사용될 수 있습니다.

Availability: Unix.

os.readlink(path, *, dir_fd=None)

심볼릭 링크가 가리키는 경로를 나타내는 문자열을 반환합니다. 결과는 절대 또는 상대 경로명일 수 있습니다; 상대 경로이면 os.path.join(os.path.dirname(path), result)를 사용하여 절대 경로명으로 변환할 수 있습니다.

path 가 (직접 또는 PathLike 인터페이스를 통해 간접적으로) 문자열 객체면, 결과도 문자열 객체가 되고, 호출은 UnicodeDecodeError를 발생시킬 수 있습니다. path 가 (직접 또는 간접적으로) 바이트열 객체면, 결과는 바이트열 객체가 됩니다.

이 기능은 디렉터리 기술자에 상대적인 경로도 지원할 수 있습니다.

링크를 포함할 수 있는 경로를 결정(resolve)하려고 할 때, realpath()를 사용하여 재귀와 플랫폼 차이를 올바르게 처리하십시오.

Availability: Unix, Windows.

버전 3.2에서 변경: 윈도우 6.0 (Vista) 심볼릭 링크에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 유닉스에서 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서 경로류 객체와 바이트열 객체를 받아들입니다.

디렉터리 정션(directory junction)에 대한 지원이 추가되었고, 이전에 반환되던 선택적 “print name” 필드 대신 치환 경로(일반적으로 \\?\ 접두사를 포함합니다)를 반환하도록 변경되었습니다.

os.remove(path, *, dir_fd=None)

Remove (delete) the file path. If path is a directory, an OSError is raised. Use rmdir() to remove directories. If the file does not exist, a FileNotFoundError is raised.

이 함수는 디렉터리 기술자에 상대적인 경로를 지원할 수 있습니다.

윈도우에서, 사용 중인 파일을 제거하려고 시도하면 예외가 발생합니다; 유닉스에서는 디렉터리 항목이 제거되지만, 원본 파일이 더는 사용되지 않을 때까지 파일에 할당된 저장 공간을 사용할 수 없습니다.

이 함수는 의미 적으로 unlink()와 같습니다.

path, dir_fd를 인자로 감사 이벤트(auditing event) os.remove를 발생시킵니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.removedirs(name)

재귀적으로 디렉터리를 제거합니다. rmdir() 처럼 동작하는데 다음과 같은 차이가 있습니다. 말단 디렉터리가 성공적으로 제거되면, removedirs()는 에러가 발생할 때까지 path에 언급된 모든 상위 디렉터리를 연속적으로 제거하려고 합니다 (에러는 무시되는데, 이는 일반적으로 부모 디렉터리가 비어 있음을 뜻하기 때문입니다). 예를 들어, os.removedirs('foo/bar/baz')는 먼저 'foo/bar/baz' 디렉터리를 제거한 다음, 'foo/bar' 및 'foo'가 비어 있으면 제거합니다. 말단 디렉터리를 성공적으로 제거할 수 없으면, OSError를 발생시킵니다.

path, dir_fd를 인자로 감사 이벤트(auditing event) os.remove를 발생시킵니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)

파일 또는 디렉터리 src의 이름을 dst로 바꿉니다. dst가 존재하면, 많은 경우에 OSError 서브 클래스로 연산이 실패합니다:

On Windows, if dst exists a FileExistsError is always raised. The operation may fail if src and dst are on different filesystems. Use shutil.move() to support moves to a different filesystem.

On Unix, if src is a file and dst is a directory or vice-versa, an IsADirectoryError or a NotADirectoryError will be raised respectively. If both are directories and dst is empty, dst will be silently replaced. If dst is a non-empty directory, an OSError is raised. If both are files, dst will be replaced silently if the user has permission. The operation may fail on some Unix flavors if src and dst are on different filesystems. If successful, the renaming will be an atomic operation (this is a POSIX requirement).

이 함수는 디렉터리 기술자에 상대적인 경로를 제공하도록 src_dir_fd 와/나 dst_dir_fd 를 지정하는 것을 지원할 수 있습니다.

플랫폼에 무관하게 대상을 덮어쓰길 원하면, replace()를 사용하십시오.

src, dst, src_dir_fd, dst_dir_fd를 인자로 감사 이벤트(auditing event) os.rename을 발생시킵니다.

버전 3.3에서 변경: Added the src_dir_fd and dst_dir_fd parameters.

버전 3.6에서 변경: src 및 dst로 경로류 객체를 받아들입니다.

os.renames(old, new)

재귀적 디렉터리 또는 파일 이름 바꾸기 함수. rename()처럼 작동하지만, 새 경로명이 유효하도록 만들기 위해 먼저 필요한 중간 디렉터리를 만드는 점이 다릅니다. 이름을 변경한 후에는, 이전 이름의 가장 오른쪽 경로 세그먼트에 해당하는 디렉터리를 removedirs()를 사용하여 제거합니다.

참고

이 함수는 말단 디렉터리나 파일을 제거하는 데 필요한 권한이 없을 때, 새 디렉터리 구조를 만든 상태에서 실패할 수 있습니다.

src, dst, src_dir_fd, dst_dir_fd를 인자로 감사 이벤트(auditing event) os.rename을 발생시킵니다.

버전 3.6에서 변경: old 와 new 에 경로류 객체를 받아들입니다.

os.replace(src, dst, *, src_dir_fd=None, dst_dir_fd=None)

Rename the file or directory src to dst. If dst is a non-empty directory, OSError will be raised. If dst exists and is a file, it will be replaced silently if the user has permission. The operation may fail if src and dst are on different filesystems. If successful, the renaming will be an atomic operation (this is a POSIX requirement).

이 함수는 디렉터리 기술자에 상대적인 경로를 제공하도록 src_dir_fd 와/나 dst_dir_fd 를 지정하는 것을 지원할 수 있습니다.

src, dst, src_dir_fd, dst_dir_fd를 인자로 감사 이벤트(auditing event) os.rename을 발생시킵니다.

Added in version 3.3.

버전 3.6에서 변경: src 및 dst로 경로류 객체를 받아들입니다.

os.rmdir(path, *, dir_fd=None)

Remove (delete) the directory path. If the directory does not exist or is not empty, a FileNotFoundError or an OSError is raised respectively. In order to remove whole directory trees, shutil.rmtree() can be used.

이 함수는 디렉터리 기술자에 상대적인 경로를 지원할 수 있습니다.

path, dir_fd를 인자로 감사 이벤트(auditing event) os.rmdir을 발생시킵니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.scandir(path='.')

path로 지정된 디렉터리 내의 항목에 대응하는 os.DirEntry 객체의 이터레이터를 돌려줍니다. 항목은 임의의 순서로 제공되며, 특수 항목 '.' 및 '..'는 포함되지 않습니다. 이터레이터를 만든 후에 디렉터리에서 파일이 제거되거나 추가되면, 해당 파일의 항목이 포함되는지는 지정되지 않습니다.

listdir() 대신 scandir()를 사용하면, 디렉터리를 검색할 때 운영 체제가 제공한다면 os.DirEntry 객체가 파일 유형과 파일 어트리뷰트 정보를 제공하기 때문에, 이것들이 필요한 코드의 성능을 크게 개선할 수 있습니다. 모든 os.DirEntry 메서드가 시스템 호출을 수행할 수 있지만, 일반적으로 is_dir() 및 is_file()는 심볼릭 링크에 대해서만 시스템 호출을 요구합니다; os.DirEntry.stat()는 유닉스에서 항상 시스템 호출을 요구하지만 윈도우에서는 심볼릭 링크에 대해서만 시스템 호출을 요구합니다.

path 는 경로류 객체 일 수 있습니다. path 가 (직접 또는 PathLike 인터페이스를 통해 간접적으로) bytes 형이면, 각 os.DirEntry의 name 및 path 어트리뷰트의 형은 bytes입니다. 다른 모든 상황에서는 형 str이 됩니다.

이 함수는 또한 파일 기술자 지정을 지원할 수 있습니다; 파일 기술자는 디렉터리를 참조해야 합니다.

path를 인자로 감사 이벤트(auditing event) os.scandir을 발생시킵니다.

scandir() 이터레이터는 컨텍스트 관리자 프로토콜을 지원하고 다음과 같은 메서드를 제공합니다:

scandir.close()

이터레이터를 닫고 확보한 자원을 반납합니다.

이터레이터가 소진되거나 가비지 수집될 때 또는 이터레이션 중에 에러가 발생하면 자동으로 호출됩니다. 하지만 명시적으로 호출하거나 with 문을 사용하는 것이 좋습니다.

Added in version 3.6.

다음 예제는 주어진 path의 '.'로 시작하지 않는 모든 파일(디렉터리 제외)을 표시하기 위한 scandir()의 간단한 사용을 보여줍니다. entry.is_file() 호출은 일반적으로 추가 시스템 호출을 하지 않습니다:

with os.scandir(path) as it:
    for entry in it:
        if not entry.name.startswith('.') and entry.is_file():
            print(entry.name)

참고

On Unix-based systems, scandir() uses the system’s opendir() [https://pubs.opengroup.org/onlinepubs/009695399/functions/opendir.html] and readdir() [https://pubs.opengroup.org/onlinepubs/009695399/functions/readdir_r.html] functions. On Windows, it uses the Win32 FindFirstFileW [https://msdn.microsoft.com/en-us/library/windows/desktop/aa364418(v=vs.85).aspx] and FindNextFileW [https://msdn.microsoft.com/en-us/library/windows/desktop/aa364428(v=vs.85).aspx] functions.

Added in version 3.5.

버전 3.6에서 변경: Added support for the context manager protocol and the close() method. If a scandir() iterator is neither exhausted nor explicitly closed a ResourceWarning will be emitted in its destructor.

이 함수는 경로류 객체를 받아들입니다.

버전 3.7에서 변경: 유닉스에서 파일 기술자에 대한 지원이 추가되었습니다.

class os.DirEntry

디렉터리 항목의 파일 경로와 다른 파일 어트리뷰트를 노출하기 위해 scandir()에 의해 산출되는 객체.

scandir()는 추가 시스템 호출 없이 가능한 많은 정보를 제공합니다. stat() 또는 lstat() 시스템 호출이 이루어지면, os.DirEntry 객체는 결과를 캐시 합니다.

os.DirEntry 인스턴스는 수명이 긴 데이터 구조에 저장하는 용도가 아닙니다; 파일 메타 데이터가 변경되었거나 scandir()를 호출한 후 오랜 시간이 지났음을 안다면, os.stat(entry.path)를 호출하여 최신 정보를 가져오십시오.

os.DirEntry 메서드는 운영 체제 시스템 호출을 할 수 있으므로, OSError를 일으킬 수도 있습니다. 에러에 대해 매우 세부적인 제어가 필요하면, os.DirEntry 메서드 중 하나를 호출할 때 OSError를 잡은 후 적절하게 처리할 수 있습니다.

경로류 객체로 직접 사용할 수 있도록, os.DirEntry는 PathLike 인터페이스를 구현합니다.

os.DirEntry 인스턴스의 어트리뷰트 및 메서드는 다음과 같습니다:

name

scandir() path 인자에 상대적인, 항목의 기본(base) 파일명.

name 어트리뷰트는 scandir() path 인자가 bytes 형이면 bytes 고, 그렇지 않으면 str 입니다. 바이트열 파일명을 디코딩하려면 fsdecode()를 사용하십시오.

path

항목의 전체 경로명: os.path.join(scandir_path, entry.name)과 같습니다. 여기서 scandir_path 는 scandir() path 인자입니다. 경로는 scandir() path 인자가 절대 경로일 때만 절대 경로입니다. scandir() path 인자가 파일 기술자면, path 어트리뷰트는 name 어트리뷰트와 같습니다.

path 어트리뷰트는 scandir() path 인자가 bytes 형이면 bytes고, 그렇지 않으면 str 입니다. 바이트열 파일명을 디코딩하려면 fsdecode()를 사용하십시오.

inode()

항목의 아이노드(inode) 번호를 반환합니다.

결과는 os.DirEntry 객체에 캐시 됩니다. 최신 정보를 가져오려면 os.stat(entry.path, follow_symlinks=False).st_ino를 사용하십시오.

최초의 캐시 되지 않은 호출에서, 윈도우 에서는 시스템 호출이 필요하지만, 유닉스에서는 그렇지 않습니다.

is_dir(*, follow_symlinks=True)

이 항목이 디렉터리 또는 디렉터리를 가리키는 심볼릭 링크면 True를 반환합니다; 항목이 다른 종류의 파일이거나 다른 종류의 파일을 가리키면, 또는 더는 존재하지 않으면 False를 반환합니다.

follow_symlinks 가 False면, 이 항목이 디렉터리일 때만 (심볼릭 링크를 따르지 않고) True를 반환합니다; 항목이 다른 종류의 파일이거나 더는 존재하지 않으면 False를 반환합니다.

결과는 follow_symlinks 가 True 및 False일 때에 대해 별도로 os.DirEntry 객체에 캐시 됩니다. 최신 정보를 가져오려면, stat.S_ISDIR()로 os.stat()을 호출하십시오.

최초의 캐시 되지 않은 호출에서, 대부분 시스템 호출이 필요하지 않습니다. 특히, 심볼릭 링크가 아니면, 윈도우나 유닉스 모두 시스템 호출이 필요하지 않은데, 네트워크 파일 시스템과 같이 dirent.d_type == DT_UNKNOWN를 반환하는 특정 유닉스 파일 시스템은 예외입니다. 항목이 심볼릭 링크면, follow_symlinks 가 False가 아닌 이상, 심볼릭 링크를 따르기 위해 시스템 호출이 필요합니다.

이 메서드는, PermissionError와 같은, OSError를 발생시킬 수 있지만, FileNotFoundError는 잡혀서 발생하지 않습니다.

is_file(*, follow_symlinks=True)

이 항목이 파일이나 파일을 가리키는 심볼릭 링크면 True를 반환합니다; 항목이 디렉터리 또는 다른 비 파일 항목이거나, 그런 것을 가리키거나, 더는 존재하지 않으면 False를 반환합니다.

follow_symlinks 가 False면, 이 항목이 파일일 때만 (심볼릭 링크를 따르지 않고) True를 반환합니다; 항목이 디렉터리 나 다른 비 파일 항목이거나 더는 존재하지 않으면 False를 반환합니다.

결과는 os.DirEntry 객체에 캐시 됩니다. 캐싱, 시스템 호출, 예외 발생은 is_dir()과 같습니다.

is_symlink()

이 항목이 심볼릭 링크면 (망가졌다 하더라도) True를 반환합니다; 항목이 디렉터리 나 어떤 종류의 파일이거나 더는 존재하지 않으면 False를 반환합니다.

결과는 os.DirEntry 객체에 캐시 됩니다. 최신 정보를 가져오려면 os.path.islink()를 호출하십시오.

첫 번째, 캐시 되지 않은 호출에서는 시스템 호출이 필요하지 않습니다. 특히 윈도우 나 유닉스는 dirent.d_type == DT_UNKNOWN를 반환하는 특정 유닉스 파일 시스템 (예 : 네트워크 파일 시스템)을 제외하고는 시스템 호출이 필요하지 않습니다.

이 메서드는, PermissionError와 같은, OSError를 발생시킬 수 있지만, FileNotFoundError는 잡혀서 발생하지 않습니다.

is_junction()

Return True if this entry is a junction (even if broken); return False if the entry points to a regular directory, any kind of file, a symlink, or if it doesn’t exist anymore.

The result is cached on the os.DirEntry object. Call os.path.isjunction() to fetch up-to-date information.

Added in version 3.12.

stat(*, follow_symlinks=True)

이 항목의 stat_result 객체를 돌려줍니다. 이 메서드는 기본적으로 심볼릭 링크를 따릅니다; 심볼릭 링크를 stat 하려면, follow_symlinks=False 인자를 추가하십시오.

유닉스에서, 이 메서드는 항상 시스템 호출을 요구합니다. 윈도우에서, follow_symlinks 가 True이고 항목이 재해석 지점(reparse point, 예를 들어, 심볼릭 링크나 디렉터리 정션(directory junction))일 때만 시스템 호출이 필요합니다.

윈도우에서, stat_result의 st_ino, st_dev 및 st_nlink 어트리뷰트는 항상 0으로 설정됩니다. 이러한 어트리뷰트를 얻으려면 os.stat()을 호출하십시오.

결과는 follow_symlinks 가 True 및 False일 때에 대해 별도로 os.DirEntry 객체에 캐시 됩니다. 최신 정보를 가져오려면, os.stat()을 호출하십시오.

Note that there is a nice correspondence between several attributes and methods of os.DirEntry and of pathlib.Path. In particular, the name attribute has the same meaning, as do the is_dir(), is_file(), is_symlink(), is_junction(), and stat() methods.

Added in version 3.5.

버전 3.6에서 변경: PathLike 인터페이스에 대한 지원이 추가되었습니다. 윈도우에서 bytes 경로에 대한 지원이 추가되었습니다.

버전 3.12에서 변경: The st_ctime attribute of a stat result is deprecated on Windows. The file creation time is properly available as st_birthtime, and in the future st_ctime may be changed to return zero or the metadata change time, if available.

os.stat(path, *, dir_fd=None, follow_symlinks=True)

파일 또는 파일 기술자의 상태를 가져옵니다. 주어진 경로에 대해 stat() 시스템 호출과 같은 작업을 수행합니다. path 는 문자열이나 바이트열 – 직접 또는 PathLike 인터페이스를 통해 간접적으로 – 또는 열린 파일 기술자로 지정될 수 있습니다. stat_result 객체를 반환합니다.

이 함수는 일반적으로 심볼릭 링크를 따릅니다; 심볼릭 링크를 stat 하려면, 인자 follow_symlinks=False를 추가하거나 lstat()를 사용하십시오.

이 함수는 파일 기술자 지정 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

윈도우에서, follow_symlinks=False를 전달하면 심볼릭 링크와 디렉터리 정션(directory junction)을 포함하는 모든 이름 서로게이트(name-surrogate) 재해석 지점(reparse point)을 따라가지 않습니다. 링크처럼 보이지 않거나 운영 체제에서 따라갈 수 없는 다른 유형의 재해석 지점은 직접 열립니다. 여러 링크 체인을 따라갈 때, 전체 탐색을 방해하는 비 링크 대신 원래 링크가 반환될 수 있습니다. 이 경우 최종 경로에 대한 stat 결과를 얻으려면, os.path.realpath() 함수를 사용하여 가능한 한 멀리 간 경로 이름을 확인한 다음 드 결과에 대해 lstat()을 호출하십시오. 매달린(dangling) 심볼릭 링크나 정션 지점에는 적용되지 않고, 일반적인 예외가 발생합니다.

예:

>>> import os
>>> statinfo = os.stat('somefile.txt')
>>> statinfo
os.stat_result(st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027)
>>> statinfo.st_size
264

더 보기

fstat() 및 lstat() 함수.

버전 3.3에서 변경: Added the dir_fd and follow_symlinks parameters, specifying a file descriptor instead of a path.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서, 이제 운영 체제가 결정할 수 있는 모든 재해석 지점을 따라가고, follow_symlinks=False를 전달하면 모든 이름 서로게이트 재해석 지점을 따라가지 않습니다. 운영 체제가 따라갈 수 없는 재해석 지점에 도달하면, stat은 이제 에러를 발생시키는 대신 follow_symlinks=False가 지정된 것처럼 원래 경로에 대한 정보를 반환합니다.

class os.stat_result

Object whose attributes correspond roughly to the members of the stat structure. It is used for the result of os.stat(), os.fstat() and os.lstat().

어트리뷰트:

st_mode

파일 모드: 파일 유형 및 파일 모드 비트 (사용 권한).

st_ino

플랫폼에 따라 다르지만, 0이 아니면, 지정된 값의 st_dev은 파일을 고유하게 식별합니다. 일반적으로:

유닉스의 아이노드 번호,

윈도우의 파일 인덱스 [https://msdn.microsoft.com/en-us/library/aa363788]

st_dev

이 파일이 있는 장치의 식별자.

st_nlink

하드 링크 수.

st_uid

파일 소유자의 사용자 식별자.

st_gid

파일 소유자의 그룹 식별자.

st_size

일반 파일 또는 심볼릭 링크면, 바이트 단위의 파일의 크기. 심볼릭 링크의 크기는 포함하고 있는 경로명의 길이이며, 끝나는 널 바이트는 포함하지 않습니다.

타임스탬프:

st_atime

초 단위의 가장 최근의 액세스 시간.

st_mtime

초 단위의 가장 최근의 내용 수정 시간.

st_ctime

Time of most recent metadata change expressed in seconds.

버전 3.12에서 변경: st_ctime is deprecated on Windows. Use st_birthtime for the file creation time. In the future, st_ctime will contain the time of the most recent metadata change, as for other platforms.

st_atime_ns

나노초 정수 단위의 가장 최근의 액세스 시간.

Added in version 3.3.

st_mtime_ns

나노초 정수 단위의 가장 최근의 내용 수정 시간.

Added in version 3.3.

st_ctime_ns

Time of most recent metadata change expressed in nanoseconds as an integer.

Added in version 3.3.

버전 3.12에서 변경: st_ctime_ns is deprecated on Windows. Use st_birthtime_ns for the file creation time. In the future, st_ctime will contain the time of the most recent metadata change, as for other platforms.

st_birthtime

Time of file creation expressed in seconds. This attribute is not always available, and may raise AttributeError.

버전 3.12에서 변경: st_birthtime is now available on Windows.

st_birthtime_ns

Time of file creation expressed in nanoseconds as an integer. This attribute is not always available, and may raise AttributeError.

Added in version 3.12.

참고

The exact meaning and resolution of the st_atime, st_mtime, st_ctime and st_birthtime attributes depend on the operating system and the file system. For example, on Windows systems using the FAT32 file systems, st_mtime has 2-second resolution, and st_atime has only 1-day resolution. See your operating system documentation for details.

Similarly, although st_atime_ns, st_mtime_ns, st_ctime_ns and st_birthtime_ns are always expressed in nanoseconds, many systems do not provide nanosecond precision. On systems that do provide nanosecond precision, the floating-point object used to store st_atime, st_mtime, st_ctime and st_birthtime cannot preserve all of it, and as such will be slightly inexact. If you need the exact timestamps you should always use st_atime_ns, st_mtime_ns, st_ctime_ns and st_birthtime_ns.

(리눅스와 같은) 일부 유닉스 시스템에서는, 다음 어트리뷰트도 사용할 수 있습니다:

st_blocks

파일에 할당된 512-바이트 블록 수. 파일에 구멍이 있으면 st_size/512보다 작을 수 있습니다.

st_blksize

효율적인 파일 시스템 I/O를 위해 “선호되는” 블록 크기. 더 작은 크기로 파일에 기록하면 비효율적인 읽기-수정-다시 쓰기가 발생할 수 있습니다.

st_rdev

아이노드 장치면 장치 유형.

st_flags

파일에 대한 사용자 정의 플래그.

(FreeBSD와 같은) 다른 유닉스 시스템에서는, 다음 어트리뷰트를 사용할 수 있습니다 (그러나 root가 사용하려고 할 때만 채워질 수 있습니다):

st_gen

파일 생성 번호.

Solaris 및 파생 상품에서, 다음 어트리뷰트도 사용할 수 있습니다:

st_fstype

파일을 포함하는 파일 시스템의 유형을 고유하게 식별하는 문자열.

On macOS systems, the following attributes may also be available:

st_rsize

파일의 실제 크기.

st_creator

파일의 생성자.

st_type

파일 유형.

윈도우 시스템에서는, 다음 어트리뷰트도 사용할 수 있습니다:

st_file_attributes

Windows file attributes: dwFileAttributes member of the BY_HANDLE_FILE_INFORMATION structure returned by GetFileInformationByHandle(). See the FILE_ATTRIBUTE_* <stat.FILE_ATTRIBUTE_ARCHIVE> constants in the stat module.

Added in version 3.5.

st_reparse_tag

When st_file_attributes has the FILE_ATTRIBUTE_REPARSE_POINT set, this field contains the tag identifying the type of reparse point. See the IO_REPARSE_TAG_* constants in the stat module.

The standard module stat defines functions and constants that are useful for extracting information from a stat structure. (On Windows, some items are filled with dummy values.)

For backward compatibility, a stat_result instance is also accessible as a tuple of at least 10 integers giving the most important (and portable) members of the stat structure, in the order st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid, st_size, st_atime, st_mtime, st_ctime. More items may be added at the end by some implementations. For compatibility with older Python versions, accessing stat_result as a tuple always returns integers.

버전 3.5에서 변경: 윈도우는 이제 사용 가능할 때 파일 인덱스를 st_ino로 반환합니다.

버전 3.7에서 변경: Solaris/파생 제품에 st_fstype 멤버를 추가했습니다.

버전 3.8에서 변경: 윈도우에서 st_reparse_tag 멤버를 추가했습니다.

버전 3.8에서 변경: 윈도우에서, st_mode 멤버는 이제 특수 파일을 S_IFCHR, S_IFIFO 또는 S_IFBLK로 적절히 식별합니다.

버전 3.12에서 변경: On Windows, st_ctime is deprecated. Eventually, it will contain the last metadata change time, for consistency with other platforms, but for now still contains creation time. Use st_birthtime for the creation time.

On Windows, st_ino may now be up to 128 bits, depending on the file system. Previously it would not be above 64 bits, and larger file identifiers would be arbitrarily packed.

On Windows, st_rdev no longer returns a value. Previously it would contain the same as st_dev, which was incorrect.

Added the st_birthtime member on Windows.

os.statvfs(path)

Perform a statvfs() system call on the given path. The return value is an object whose attributes describe the filesystem on the given path, and correspond to the members of the statvfs structure, namely: f_bsize, f_frsize, f_blocks, f_bfree, f_bavail, f_files, f_ffree, f_favail, f_flag, f_namemax, f_fsid.

f_flag 어트리뷰트의 비트 플래그에 대해 두 개의 모듈 수준 상수가 정의됩니다: ST_RDONLY가 설정되면, 파일 시스템은 읽기 전용으로 마운트되었고, ST_NOSUID가 설정되면, setuid/setgid 비트의 의미가 비활성화되었거나 지원되지 않습니다.

추가적인 모듈 수준 상수가 GNU/glibc 기반 시스템에 대해 정의됩니다. 이들은 ST_NODEV (장치 특수 파일에 대한 액세스 금지), ST_NOEXEC (프로그램 실행 금지), ST_SYNCHRONOUS (한 번에 쓰기 동기화), ST_MANDLOCK (FS에 필수 잠금 허용), ST_WRITE (파일/디렉터리/심볼릭 링크 쓰기), ST_APPEND (덧붙이기 전용 파일), ST_IMMUTABLE (불변 파일), ST_NOATIME (액세스 시간을 갱신하지 않음), ST_NODIRATIME (디렉터리 액세스 시간을 갱신하지 않음), ST_RELATIME (mtime/ctime에 상대적으로 atime을 갱신).

이 함수는 파일 기술자 지정을 지원할 수 있습니다.

Availability: Unix.

버전 3.2에서 변경: ST_RDONLY 및 ST_NOSUID 상수가 추가되었습니다.

버전 3.3에서 변경: path에 열린 파일 기술자를 지정하는 지원이 추가되었습니다.

버전 3.4에서 변경: ST_NODEV, ST_NOEXEC, ST_SYNCHRONOUS, ST_MANDLOCK, ST_WRITE, ST_APPEND, ST_IMMUTABLE, ST_NOATIME, ST_NODIRATIME 및 ST_RELATIME 상수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.7에서 변경: Added the f_fsid attribute.

os.supports_dir_fd

os 모듈의 어떤 함수가 dir_fd 매개 변수로 열린 파일 기술자를 받아들이는지를 나타내는 set 객체. 플랫폼마다 다른 기능을 제공하며, 파이썬이 dir_fd 매개 변수를 구현하는 데 사용하는 하부 기능이 파이썬이 지원하는 모든 플랫폼에서 제공되지는 않습니다. 일관성을 위해, dir_fd 를 지원할 수도 있는 함수는 항상 매개 변수를 지정할 수 있도록 하지만, 로컬에서 사용할 수 없을 때, 기능을 사용하면 예외를 발생시킵니다. (dir_fd에 None을 지정하는 것은 모든 플랫폼에서 항상 지원됩니다.)

특정 함수가 dir_fd 매개 변수로 열린 파일 기술자를 받아들이는지 확인하려면, supports_dir_fd에 in 연산자를 사용하십시오. 예를 들어, 이 표현식은 로컬 플랫폼에서 os.stat()이 dir_fd 매개 변수로 열린 파일 기술자를 받아들이면 True로 평가됩니다:

os.stat in os.supports_dir_fd

현재 dir_fd 매개 변수는 유닉스 플랫폼에서만 작동합니다; 어느 것도 윈도우에서 작동하지 않습니다.

Added in version 3.3.

os.supports_effective_ids

os.access()가 로컬 플랫폼에서 effective_ids 매개 변수에 True를 지정하는 것을 허용하는지를 나타내는 set 객체. (effective_ids에 False를 지정하는 것은 모든 플랫폼에서 항상 지원됩니다.) 로컬 플랫폼이 지원하면, 컬렉션에 os.access()가 포함됩니다; 그렇지 않으면 비어있게 됩니다.

이 표현식은 로컬 플랫폼에서 os.access()가 effective_ids=True를 지원하면 True로 평가됩니다:

os.access in os.supports_effective_ids

현재 effective_ids 는 유닉스 플랫폼에서만 지원됩니다; 윈도우에서는 작동하지 않습니다.

Added in version 3.3.

os.supports_fd

os 모듈의 어떤 함수가 로컬 플랫폼에서 자신의 path 매개 변수에 열린 파일 기술자를 지정하는 것을 허용하는지를 나타내는 set 객체. 플랫폼마다 다른 기능을 제공하며, 파이썬이 path로 열린 파일 기술자를 받아들이는 데 사용하는 하부 기능이 파이썬이 지원하는 모든 플랫폼에서 제공되지는 않습니다.

특정 함수가 path 매개 변수에 열린 파일 기술자를 지정할 수 있도록 허용하는지를 판단하려면, supports_fd에 in 연산자를 사용하십시오. 예를 들어, 이 표현식은 로컬 플랫폼에서 os.chdir()가 path로 열린 파일 기술자를 받아들이면 True로 평가됩니다:

os.chdir in os.supports_fd

Added in version 3.3.

os.supports_follow_symlinks

os 모듈의 어떤 함수가 follow_symlinks 매개 변수로 False를 받아들이는지를 나타내는 set 객체. 플랫폼마다 다른 기능을 제공하며, 파이썬이 follow_symlinks를 구현하는 데 사용하는 하부 기능이 파이썬이 지원하는 모든 플랫폼에서 제공되지는 않습니다. 일관성을 위해, follow_symlinks 를 지원할 수도 있는 함수는 항상 매개 변수를 지정할 수 있도록 하지만, 로컬에서 사용할 수 없을 때, 기능이 사용되면 예외를 발생시킵니다. (follow_symlinks에 None을 지정하는 것은 모든 플랫폼에서 항상 지원됩니다.)

특정 함수가 follow_symlinks 매개 변수로 False를 받아들이는지 확인하려면, supports_follow_symlinks에 in 연산자를 사용하십시오. 예를 들어, 이 표현식은 로컬 플랫폼에서 os.stat()을 호출할 때 follow_symlinks=False를 지정할 수 있으면 True로 평가됩니다:

os.stat in os.supports_follow_symlinks

Added in version 3.3.

os.symlink(src, dst, target_is_directory=False, *, dir_fd=None)

src를 가리키는 dst 라는 이름의 심볼릭 링크를 만듭니다.

윈도우에서, 심볼릭 링크는 파일이나 디렉터리를 나타내며, 동적으로 대상에 맞춰 변형되지 않습니다. 대상이 있으면, 일치하도록 심볼릭 링크의 유형이 만들어집니다. 그렇지 않으면, target_is_directory 가 True 면 심볼릭 링크가 디렉터리로 만들어지고, 그렇지 않으면 파일 심볼릭 링크(기본값)가 만들어집니다. 비 윈도우 플랫폼에서는 target_is_directory 가 무시됩니다.

이 함수는 디렉터리 기술자에 상대적인 경로를 지원할 수 있습니다.

참고

최신 버전의 윈도우 10에서, 개발자 모드가 활성화되면, 권한이 없는 계정이 심볼릭 링크를 만들 수 있습니다. 개발자 모드를 사용할 수 없거나 활성화되어 있지 않으면, SeCreateSymbolicLinkPrivilege 권한이 필요하거나, 프로세스를 관리자로 실행해야 합니다.

권한이 없는 사용자가 함수를 호출하면 OSError가 발생합니다.

src, dst, dir_fd를 인자로 감사 이벤트(auditing event) os.symlink를 발생시킵니다.

Availability: Unix, Windows.

The function is limited on WASI, see WebAssembly platforms for more information.

버전 3.2에서 변경: 윈도우 6.0 (Vista) 심볼릭 링크에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: Added the dir_fd parameter, and now allow target_is_directory on non-Windows platforms.

버전 3.6에서 변경: src 및 dst로 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 개발자 모드가 있는 윈도우에서 권한 상승 없는(unelevated) 심볼릭 링크에 대한 지원이 추가되었습니다.

os.sync()

디스크에 모든 것을 쓰도록 강제합니다.

Availability: Unix.

Added in version 3.3.

os.truncate(path, length)

최대 length 바이트가 되도록 path에 해당하는 파일을 자릅니다.

이 함수는 파일 기술자 지정을 지원할 수 있습니다.

path, length를 인자로 감사 이벤트(auditing event) os.truncate를 발생시킵니다.

Availability: Unix, Windows.

Added in version 3.3.

버전 3.5에서 변경: 윈도우 지원 추가

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.unlink(path, *, dir_fd=None)

파일 path를 제거(삭제)합니다. 이 함수는 의미상 remove()와 같습니다; unlink 라는 이름은 전통적인 유닉스 이름입니다. 자세한 내용은 remove() 설명서를 참조하십시오.

path, dir_fd를 인자로 감사 이벤트(auditing event) os.remove를 발생시킵니다.

버전 3.3에서 변경: dir_fd 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.utime(path, times=None, *, [ns, ]dir_fd=None, follow_symlinks=True)

path로 지정된 파일의 액세스 및 수정 시간을 설정합니다.

utime()은 times 과 ns 라는 두 개의 선택적 매개 변수를 취합니다. path에 설정할 시간을 지정하며 다음과 같이 사용됩니다:

ns 가 지정되면, (atime_ns, mtime_ns) 형식의 2-튜플이어야 하며, 각 멤버는 나노초를 나타내는 int입니다.

times 가 None이 아니면, (atime, mtime) 형식의 2-튜플이어야 하며, 각 멤버는 초를 나타내는 int 또는 float입니다.

times 가 None이고 ns 가 지정되지 않으면, ns=(atime_ns, mtime_ns)를 지정하는 것과 같은데, 두 시간 모두 현재 시각입니다.

times 와 ns에 모두 튜플을 지정하는 것은 에러입니다.

Note that the exact times you set here may not be returned by a subsequent stat() call, depending on the resolution with which your operating system records access and modification times; see stat(). The best way to preserve exact times is to use the st_atime_ns and st_mtime_ns fields from the os.stat() result object with the ns parameter to utime().

이 함수는 파일 기술자 지정, 디렉터리 기술자에 상대적인 경로 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

path, times, ns, dir_fd를 인자로 감사 이벤트(auditing event) os.utime을 발생시킵니다.

버전 3.3에서 변경: path에 열린 파일 기술자를 지정하는 것과 dir_fd , follow_symlinks 및 ns 매개 변수 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.walk(top, topdown=True, onerror=None, followlinks=False)

트리를 하향식 또는 상향식으로 탐색하여 디렉터리 트리에 있는 파일명을 생성합니다. 디렉터리 top을 루트로 하는 트리의 디렉터리(top 자체를 포함합니다)마다, 3-튜플 (dirpath, dirnames, filenames)를 산출합니다.

dirpath is a string, the path to the directory. dirnames is a list of the names of the subdirectories in dirpath (including symlinks to directories, and excluding '.' and '..'). filenames is a list of the names of the non-directory files in dirpath. Note that the names in the lists contain no path components. To get a full path (which begins with top) to a file or directory in dirpath, do os.path.join(dirpath, name). Whether or not the lists are sorted depends on the file system. If a file is removed from or added to the dirpath directory during generating the lists, whether a name for that file be included is unspecified.

선택적 인자 topdown 이 True이거나 지정되지 않으면, 디렉터리에 대한 3-튜플은 하위 디렉터리에 대한 3-튜플이 생성되기 전에 생성됩니다 (디렉터리는 하향식으로 생성됩니다). topdown 이 False면, 모든 하위 디렉터리에 대한 3-튜플 다음에 디렉터리에 대한 3-튜플이 생성됩니다 (디렉터리가 상향식으로 생성됨). topdown 의 값에 상관없이, 디렉터리와 해당 하위 디렉터리의 튜플이 생성되기 전에 하위 디렉터리 목록이 조회됩니다.

topdown 이 True 일 때, 호출자는 (아마도 del 또는 슬라이스 대입을 사용하여) dirnames 리스트를 수정할 수 있으며, walk()는 이름이 dirnames 남아있는 하위 디렉터리로만 재귀합니다; 검색을 가지치기하거나, 특정 방문 순서를 지정하거나, 심지어 walk()가 다시 시작하기 전에 호출자가 새로 만들거나 이름을 바꾼 디렉터리에 대해 walk()에 알릴 때도 사용할 수 있습니다. topdown 이 False일 때 dirnames를 수정하는 것은 walk의 동작에 영향을 주지 못하는데, 상향식 모드에서 dirnames의 디렉터리는 dirpath 자체가 생성되기 전에 생성되기 때문입니다.

기본적으로, scandir() 호출의 에러는 무시됩니다. 선택적 인자 onerror 가 지정되면, 함수여야 합니다; 하나의 인자 OSError 인스턴스로 호출됩니다. 에러를 보고하고 walk를 계속하도록 하거나, 예외를 발생시켜 walk를 중단할 수 있습니다. 파일명은 예외 객체의 filename 어트리뷰트로 제공됩니다.

기본적으로, walk()는 디렉터리로 해석되는 심볼릭 링크로 이동하지 않습니다. 지원하는 시스템에서, 심볼릭 링크가 가리키는 디렉터리를 방문하려면, followlinks를 True로 설정하십시오.

참고

심볼릭 링크가 자신의 부모 디렉터리를 가리킬 때, followlinks를 True로 설정하면 무한 재귀가 발생할 수 있음에 주의해야 합니다. walk()는 이미 방문한 디렉터리를 추적하지 않습니다.

참고

상대 경로명을 전달할 때는, walk()가 실행되는 도중 현재 작업 디렉터리를 변경하지 마십시오. walk()는 현재 디렉터리를 절대로 변경하지 않으며, 호출자도 마찬가지라고 가정합니다.

이 예는 시작 디렉터리 아래의 각 디렉터리에 있는 비 디렉터리 파일이 차지한 바이트 수를 표시합니다. 단, CVS 하위 디렉터리 아래는 보지 않습니다:

import os
from os.path import join, getsize
for root, dirs, files in os.walk('python/Lib/email'):
    print(root, "consumes", end=" ")
    print(sum(getsize(join(root, name)) for name in files), end=" ")
    print("bytes in", len(files), "non-directory files")
    if 'CVS' in dirs:
        dirs.remove('CVS')  # don't visit CVS directories

다음 예(shutil.rmtree()의 간단한 구현)에서는, 트리를 상향식으로 탐색하는 것이 필수적입니다, rmdir()는 비어 있지 않은 디렉터리를 삭제할 수 없습니다:

# Delete everything reachable from the directory named in "top",
# assuming there are no symbolic links.
# CAUTION:  This is dangerous!  For example, if top == '/', it
# could delete all your disk files.
import os
for root, dirs, files in os.walk(top, topdown=False):
    for name in files:
        os.remove(os.path.join(root, name))
    for name in dirs:
        os.rmdir(os.path.join(root, name))
os.rmdir(top)

top, topdown, onerror, followlinks를 인자로 감사 이벤트(auditing event) os.walk를 발생시킵니다.

버전 3.5에서 변경: 이 함수는 이제 os.listdir() 대신 os.scandir()를 호출하기 때문에, os.stat() 호출 수를 줄여 더 빨라졌습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.fwalk(top='.', topdown=True, onerror=None, *, follow_symlinks=False, dir_fd=None)

이 함수는 walk()와 똑같이 동작합니다. 단, 4-튜플 (dirpath, dirnames, filenames, dirfd)를 산출하고 dir_fd를 지원합니다.

dirpath , dirnames 및 filenames 은 walk() 출력과 같고, dirfd 는 dirpath 디렉터리를 가리키는 파일 기술자입니다.

이 함수는 항상 디렉터리 기술자에 상대적인 경로 및 심볼릭 링크를 따르지 않음을 지원합니다. 하지만, 다른 함수와는 달리, follow_symlinks에 대한 fwalk()의 기본값은 False임에 주의하십시오.

참고

fwalk()는 다음 이터레이션 단계까지만 유효한 파일 기술자를 산출하기 때문에, 더 오래 유지하려면 복제해야 합니다 (예를 들어, dup()로).

이 예는 시작 디렉터리 아래의 각 디렉터리에 있는 비 디렉터리 파일이 차지한 바이트 수를 표시합니다. 단, CVS 하위 디렉터리 아래는 보지 않습니다:

import os
for root, dirs, files, rootfd in os.fwalk('python/Lib/email'):
    print(root, "consumes", end="")
    print(sum([os.stat(name, dir_fd=rootfd).st_size for name in files]),
          end="")
    print("bytes in", len(files), "non-directory files")
    if 'CVS' in dirs:
        dirs.remove('CVS')  # don't visit CVS directories

다음 예에서는, 트리를 상향식으로 탐색하는 것이 필수적입니다: rmdir()는 비어 있지 않은 디렉터리를 삭제할 수 없습니다:

# Delete everything reachable from the directory named in "top",
# assuming there are no symbolic links.
# CAUTION:  This is dangerous!  For example, if top == '/', it
# could delete all your disk files.
import os
for root, dirs, files, rootfd in os.fwalk(top, topdown=False):
    for name in files:
        os.unlink(name, dir_fd=rootfd)
    for name in dirs:
        os.rmdir(name, dir_fd=rootfd)

top, topdown, onerror, follow_symlinks, dir_fd를 인자로 감사 이벤트(auditing event) os.fwalk를 발생시킵니다.

Availability: Unix.

Added in version 3.3.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.7에서 변경: bytes 경로에 대한 지원이 추가되었습니다.

os.memfd_create(name[, flags=os.MFD_CLOEXEC])

익명 파일을 만들고 이를 가리키는 파일 기술자를 반환합니다. flags는 시스템에서 사용할 수 있는 os.MFD_* 상수(또는 이들의 비트별 OR 조합) 중 하나여야 합니다. 기본적으로, 새 파일 기술자는 상속 불가능합니다.

name에 제공된 이름은 파일명으로 사용되며 해당 심볼릭 링크의 대상으로 /proc/self/fd/ 디렉터리에 표시됩니다. 표시된 이름에는 항상 memfd: 접두어가 붙으며 디버깅 목적으로만 사용됩니다. 이름은 파일 기술자의 동작에 영향을 미치지 않고, 여러 파일이 부작용 없이 같은 이름을 가질 수 있습니다.

Availability: Linux >= 3.17 with glibc >= 2.27.

Added in version 3.8.

os.MFD_CLOEXEC

os.MFD_ALLOW_SEALING

os.MFD_HUGETLB

os.MFD_HUGE_SHIFT

os.MFD_HUGE_MASK

os.MFD_HUGE_64KB

os.MFD_HUGE_512KB

os.MFD_HUGE_1MB

os.MFD_HUGE_2MB

os.MFD_HUGE_8MB

os.MFD_HUGE_16MB

os.MFD_HUGE_32MB

os.MFD_HUGE_256MB

os.MFD_HUGE_512MB

os.MFD_HUGE_1GB

os.MFD_HUGE_2GB

os.MFD_HUGE_16GB

이 플래그들은 memfd_create()로 전달될 수 있습니다.

Availability: Linux >= 3.17 with glibc >= 2.27

The MFD_HUGE* flags are only available since Linux 4.14.

Added in version 3.8.

os.eventfd(initval[, flags=os.EFD_CLOEXEC])

Create and return an event file descriptor. The file descriptors supports raw read() and write() with a buffer size of 8, select(), poll() and similar. See man page eventfd(2) [https://manpages.debian.org/eventfd(2)] for more information. By default, the new file descriptor is non-inheritable.

initval is the initial value of the event counter. The initial value must be a 32 bit unsigned integer. Please note that the initial value is limited to a 32 bit unsigned int although the event counter is an unsigned 64 bit integer with a maximum value of 2⁶⁴-2.

flags can be constructed from EFD_CLOEXEC, EFD_NONBLOCK, and EFD_SEMAPHORE.

If EFD_SEMAPHORE is specified and the event counter is non-zero, eventfd_read() returns 1 and decrements the counter by one.

If EFD_SEMAPHORE is not specified and the event counter is non-zero, eventfd_read() returns the current event counter value and resets the counter to zero.

If the event counter is zero and EFD_NONBLOCK is not specified, eventfd_read() blocks.

eventfd_write() increments the event counter. Write blocks if the write operation would increment the counter to a value larger than 2⁶⁴-2.

예:

import os

# semaphore with start value '1'
fd = os.eventfd(1, os.EFD_SEMAPHORE | os.EFC_CLOEXEC)
try:
    # acquire semaphore
    v = os.eventfd_read(fd)
    try:
        do_work()
    finally:
        # release semaphore
        os.eventfd_write(fd, v)
finally:
    os.close(fd)

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.10.

os.eventfd_read(fd)

Read value from an eventfd() file descriptor and return a 64 bit unsigned int. The function does not verify that fd is an eventfd().

Availability: Linux >= 2.6.27

Added in version 3.10.

os.eventfd_write(fd, value)

Add value to an eventfd() file descriptor. value must be a 64 bit unsigned int. The function does not verify that fd is an eventfd().

Availability: Linux >= 2.6.27

Added in version 3.10.

os.EFD_CLOEXEC

Set close-on-exec flag for new eventfd() file descriptor.

Availability: Linux >= 2.6.27

Added in version 3.10.

os.EFD_NONBLOCK

Set O_NONBLOCK status flag for new eventfd() file descriptor.

Availability: Linux >= 2.6.27

Added in version 3.10.

os.EFD_SEMAPHORE

Provide semaphore-like semantics for reads from an eventfd() file descriptor. On read the internal counter is decremented by one.

Availability: Linux >= 2.6.30

Added in version 3.10.

Timer File Descriptors

Added in version 3.13.

These functions provide support for Linux’s timer file descriptor API. Naturally, they are all only available on Linux.

os.timerfd_create(clockid, /, *, flags=0)

Create and return a timer file descriptor (timerfd).

The file descriptor returned by timerfd_create() supports:

read()

select()

poll()

The file descriptor’s read() method can be called with a buffer size of 8. If the timer has already expired one or more times, read() returns the number of expirations with the host’s endianness, which may be converted to an int by int.from_bytes(x, byteorder=sys.byteorder).

select() and poll() can be used to wait until timer expires and the file descriptor is readable.

clockid must be a valid clock ID, as defined in the time module:

time.CLOCK_REALTIME

time.CLOCK_MONOTONIC

time.CLOCK_BOOTTIME (Since Linux 3.15 for timerfd_create)

If clockid is time.CLOCK_REALTIME, a settable system-wide real-time clock is used. If system clock is changed, timer setting need to be updated. To cancel timer when system clock is changed, see TFD_TIMER_CANCEL_ON_SET.

If clockid is time.CLOCK_MONOTONIC, a non-settable monotonically increasing clock is used. Even if the system clock is changed, the timer setting will not be affected.

If clockid is time.CLOCK_BOOTTIME, same as time.CLOCK_MONOTONIC except it includes any time that the system is suspended.

The file descriptor’s behaviour can be modified by specifying a flags value. Any of the following variables may used, combined using bitwise OR (the | operator):

TFD_NONBLOCK

TFD_CLOEXEC

If TFD_NONBLOCK is not set as a flag, read() blocks until the timer expires. If it is set as a flag, read() doesn’t block, but If there hasn’t been an expiration since the last call to read, read() raises OSError with errno is set to errno.EAGAIN.

TFD_CLOEXEC is always set by Python automatically.

The file descriptor must be closed with os.close() when it is no longer needed, or else the file descriptor will be leaked.

더 보기

The timerfd_create(2) [https://manpages.debian.org/timerfd_create(2)] man page.

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.timerfd_settime(fd, /, *, flags=flags, initial=0.0, interval=0.0)

Alter a timer file descriptor’s internal timer. This function operates the same interval timer as timerfd_settime_ns().

fd must be a valid timer file descriptor.

The timer’s behaviour can be modified by specifying a flags value. Any of the following variables may used, combined using bitwise OR (the | operator):

TFD_TIMER_ABSTIME

TFD_TIMER_CANCEL_ON_SET

The timer is disabled by setting initial to zero (0). If initial is equal to or greater than zero, the timer is enabled. If initial is less than zero, it raises an OSError exception with errno set to errno.EINVAL

By default the timer will fire when initial seconds have elapsed. (If initial is zero, timer will fire immediately.)

However, if the TFD_TIMER_ABSTIME flag is set, the timer will fire when the timer’s clock (set by clockid in timerfd_create()) reaches initial seconds.

The timer’s interval is set by the interval float. If interval is zero, the timer only fires once, on the initial expiration. If interval is greater than zero, the timer fires every time interval seconds have elapsed since the previous expiration. If interval is less than zero, it raises OSError with errno set to errno.EINVAL

If the TFD_TIMER_CANCEL_ON_SET flag is set along with TFD_TIMER_ABSTIME and the clock for this timer is time.CLOCK_REALTIME, the timer is marked as cancelable if the real-time clock is changed discontinuously. Reading the descriptor is aborted with the error ECANCELED.

Linux manages system clock as UTC. A daylight-savings time transition is done by changing time offset only and doesn’t cause discontinuous system clock change.

Discontinuous system clock change will be caused by the following events:

settimeofday

clock_settime

set the system date and time by date command

Return a two-item tuple of (next_expiration, interval) from the previous timer state, before this function executed.

더 보기

timerfd_create(2) [https://manpages.debian.org/timerfd_create(2)], timerfd_settime(2) [https://manpages.debian.org/timerfd_settime(2)], settimeofday(2) [https://manpages.debian.org/settimeofday(2)], clock_settime(2) [https://manpages.debian.org/clock_settime(2)], and date(1) [https://manpages.debian.org/date(1)].

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.timerfd_settime_ns(fd, /, *, flags=0, initial=0, interval=0)

Similar to timerfd_settime(), but use time as nanoseconds. This function operates the same interval timer as timerfd_settime().

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.timerfd_gettime(fd, /)

Return a two-item tuple of floats (next_expiration, interval).

next_expiration denotes the relative time until next the timer next fires, regardless of if the TFD_TIMER_ABSTIME flag is set.

interval denotes the timer’s interval. If zero, the timer will only fire once, after next_expiration seconds have elapsed.

더 보기

timerfd_gettime(2) [https://manpages.debian.org/timerfd_gettime(2)]

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.timerfd_gettime_ns(fd, /)

Similar to timerfd_gettime(), but return time as nanoseconds.

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.TFD_NONBLOCK

A flag for the timerfd_create() function, which sets the O_NONBLOCK status flag for the new timer file descriptor. If TFD_NONBLOCK is not set as a flag, read() blocks.

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.TFD_CLOEXEC

A flag for the timerfd_create() function, If TFD_CLOEXEC is set as a flag, set close-on-exec flag for new file descriptor.

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.TFD_TIMER_ABSTIME

A flag for the timerfd_settime() and timerfd_settime_ns() functions. If this flag is set, initial is interpreted as an absolute value on the timer’s clock (in UTC seconds or nanoseconds since the Unix Epoch).

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

os.TFD_TIMER_CANCEL_ON_SET

A flag for the timerfd_settime() and timerfd_settime_ns() functions along with TFD_TIMER_ABSTIME. The timer is cancelled when the time of the underlying clock changes discontinuously.

Availability: Linux >= 2.6.27 with glibc >= 2.8

Added in version 3.13.

리눅스 확장 어트리뷰트

Added in version 3.3.

이 함수들은 모두 리눅스에서만 사용 가능합니다.

os.getxattr(path, attribute, *, follow_symlinks=True)

path의 확장 파일 시스템 어트리뷰트 attribute의 값을 반환합니다. attribute 는 bytes 또는 str(직접 또는 PathLike 인터페이스를 통해 간접적으로)일 수 있습니다. str이면, 파일 시스템 인코딩으로 인코딩됩니다.

이 함수는 파일 기술자 지정 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

path, attribute를 인자로 감사 이벤트(auditing event) os.getxattr을 발생시킵니다.

버전 3.6에서 변경: path 및 attribute에 대해 경로류 객체를 받아들입니다.

os.listxattr(path=None, *, follow_symlinks=True)

path 의 확장 파일 시스템 어트리뷰트 목록을 반환합니다. 목록의 어트리뷰트는 파일 시스템 인코딩으로 디코딩된 문자열로 표시됩니다. path 가 None이면, listxattr()는 현재 디렉터리를 검사합니다.

이 함수는 파일 기술자 지정 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

path를 인자로 감사 이벤트(auditing event) os.listxattr을 발생시킵니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os.removexattr(path, attribute, *, follow_symlinks=True)

Removes the extended filesystem attribute attribute from path. attribute should be bytes or str (directly or indirectly through the PathLike interface). If it is a string, it is encoded with the filesystem encoding and error handler.

이 함수는 파일 기술자 지정 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

path, attribute를 인자로 감사 이벤트(auditing event) os.removexattr을 발생시킵니다.

버전 3.6에서 변경: path 및 attribute에 대해 경로류 객체를 받아들입니다.

os.setxattr(path, attribute, value, flags=0, *, follow_symlinks=True)

Set the extended filesystem attribute attribute on path to value. attribute must be a bytes or str with no embedded NULs (directly or indirectly through the PathLike interface). If it is a str, it is encoded with the filesystem encoding and error handler. flags may be XATTR_REPLACE or XATTR_CREATE. If XATTR_REPLACE is given and the attribute does not exist, ENODATA will be raised. If XATTR_CREATE is given and the attribute already exists, the attribute will not be created and EEXISTS will be raised.

이 함수는 파일 기술자 지정 및 심볼릭 링크를 따르지 않음을 지원할 수 있습니다.

참고

리눅스 커널 버전 2.6.39 미만의 버그로 인해 flags 인자가 일부 파일 시스템에서 무시되었습니다.

path, attribute, value, flags를 인자로 감사 이벤트(auditing event) os.setxattr을 발생시킵니다.

버전 3.6에서 변경: path 및 attribute에 대해 경로류 객체를 받아들입니다.

os.XATTR_SIZE_MAX

확장 어트리뷰트 값의 최대 크기입니다. 현재, 리눅스에서 64 KiB입니다.

os.XATTR_CREATE

이것은 setxattr()의 flags 인자를 위한 값입니다. 연산이 반드시 어트리뷰트를 새로 만들어야 함을 나타냅니다.

os.XATTR_REPLACE

이것은 setxattr()의 flags 인자를 위한 값입니다. 연산이 반드시 기존 어트리뷰트를 대체해야 함을 나타냅니다.

프로세스 관리

이 함수들은 프로세스를 만들고 관리하는데 사용될 수 있습니다.

다양한 exec* 함수는 프로세스로 로드되는 새 프로그램에 대한 인자 목록을 받아들입니다. 각각의 경우에, 첫 번째 인자는 사용자가 명령 줄에 입력할 수 있는 인자가 아닌 프로그램 자체의 이름으로 새 프로그램에 전달됩니다. C 프로그래머에게, 이것은 프로그램의 main()에 전달된 argv[0]입니다. 예를 들어, os.execv('/bin/echo', ['foo', 'bar'])는 표준 출력에 bar만 인쇄합니다; foo는 무시되는 것처럼 보이게 됩니다.

os.abort()

현재 프로세스에 SIGABRT 시그널을 생성합니다. 유닉스에서, 기본 동작은 코어 덤프를 생성하는 것입니다; 윈도우에서, 프로세스는 즉시 종료 코드 3을 반환합니다. 이 함수를 호출하면 signal.signal()를 사용하여 SIGABRT에 등록된 파이썬 시그널 처리기를 호출하지 않게 됨에 주의하시기 바랍니다.

os.add_dll_directory(path)

DLL 검색 경로에 path를 추가합니다.

This search path is used when resolving dependencies for imported extension modules (the module itself is resolved through sys.path), and also by ctypes.

반환된 객체의 close()를 호출하거나 반환된 객체를 with 문에서 사용하여 디렉터리를 제거하십시오.

DLL이 로드되는 방법에 대한 자세한 내용은 마이크로소프트 설명서 [https://msdn.microsoft.com/44228cf2-6306-466c-8f16-f513cd3ba8b5]를 참조하십시오.

path를 인자로 감사 이벤트(auditing event) os.add_dll_directory를 발생시킵니다.

Availability: Windows.

Added in version 3.8: 이전 버전의 CPython은 현재 프로세스의 기본 동작을 사용하여 DLL을 해결(resolve)합니다. 이로 인해 때때로 PATH나 현재 작업 디렉터리를 검색하거나, AddDllDirectory와 같은 OS 함수가 효과가 없게 되는 것과 같은 일관성 없는 결과를 낳습니다.

3.8에서는, 일관성을 보장하기 위해 이제 DLL이 로드되는 두 가지 기본 방법이 프로세스 전반의 동작을 명시적으로 재정의합니다. 라이브러리 갱신에 대한 정보는 이식 주의 사항을 참조하십시오.

os.execl(path, arg0, arg1, ...)

os.execle(path, arg0, arg1, ..., env)

os.execlp(file, arg0, arg1, ...)

os.execlpe(file, arg0, arg1, ..., env)

os.execv(path, args)

os.execve(path, args, env)

os.execvp(file, args)

os.execvpe(file, args, env)

이 함수들은 모두 현재 프로세스를 대체해서 새로운 프로그램을 실행합니다; 반환되지 않습니다. 유닉스에서, 새로운 실행 파일이 현재 프로세스에 로드되고, 호출자와 같은 프로세스 ID를 갖게 됩니다. 에러는 OSError 예외로 보고됩니다.

현재 프로세스가 즉시 교체됩니다. 열린 파일 객체와 기술자는 플러시 되지 않으므로, 이러한 열린 파일에 버퍼링 된 데이터가 있으면, exec* 함수를 호출하기 전에 sys.stdout.flush() 또는 os.fsync()를 사용하여 플러시 해야 합니다.

The “l” and “v” variants of the exec* functions differ in how command-line arguments are passed. The “l” variants are perhaps the easiest to work with if the number of parameters is fixed when the code is written; the individual parameters simply become additional parameters to the execl*() functions. The “v” variants are good when the number of parameters is variable, with the arguments being passed in a list or tuple as the args parameter. In either case, the arguments to the child process should start with the name of the command being run, but this is not enforced.

The variants which include a “p” near the end (execlp(), execlpe(), execvp(), and execvpe()) will use the PATH environment variable to locate the program file. When the environment is being replaced (using one of the exec*e variants, discussed in the next paragraph), the new environment is used as the source of the PATH variable. The other variants, execl(), execle(), execv(), and execve(), will not use the PATH variable to locate the executable; path must contain an appropriate absolute or relative path. Relative paths must include at least one slash, even on Windows, as plain names will not be resolved.

execle(), execlpe(), execve(), execvpe()의 경우 (모두 “e”로 끝납니다), env 매개 변수는 새 프로세스의 환경 변수를 정의하는 데 사용되는 매핑이어야 합니다 (이것이 현재 프로세스의 환경 대신 사용됩니다); 함수 execl(), execlp(), execv() 및 execvp()는 모두 새 프로세스가 현재 프로세스의 환경을 상속하게 합니다.

일부 플랫폼에서 execve()의 경우, path 는 열린 파일 기술자로도 지정될 수 있습니다. 이 기능은 여러분의 플랫폼에서 지원되지 않을 수 있습니다; os.supports_fd를 사용하여 사용할 수 있는지를 확인할 수 있습니다. 사용할 수 없을 때, 이를 사용하면 NotImplementedError가 발생합니다.

path, args, env를 인자로 감사 이벤트(auditing event) os.exec를 발생시킵니다.

Availability: Unix, Windows, not WASI, not Android, not iOS.

버전 3.3에서 변경: execve()의 path에 열린 파일 기술자를 지정하는 지원이 추가되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

os._exit(n)

상태 n으로 프로세스를 종료합니다. 클린업 처리기를 호출하거나, stdio 버퍼를 플러시 하거나 등등은 수행하지 않습니다.

참고

The standard way to exit is sys.exit(n). _exit() should normally only be used in the child process after a fork().

필수 조건은 아니지만, 다음 종료 코드가 정의되어 있으며 _exit()와 함께 사용할 수 있습니다. 이것은 메일 서버의 외부 명령 배달 프로그램과 같이 파이썬으로 작성된 시스템 프로그램에서 일반적으로 사용됩니다.

참고

약간의 차이점이 있어서, 이들 중 일부는 모든 유닉스 플랫폼에서 사용하지는 못할 수 있습니다. 이 상수는 하부 플랫폼에서 정의될 때만 정의됩니다.

os.EX_OK

Exit code that means no error occurred. May be taken from the defined value of EXIT_SUCCESS on some platforms. Generally has a value of zero.

Availability: Unix, Windows.

os.EX_USAGE

잘못된 개수의 인자가 제공된 경우처럼, 명령이 잘못 사용되었음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_DATAERR

입력 데이터가 잘못되었음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_NOINPUT

입력 파일이 없거나 읽을 수 없음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_NOUSER

지정된 사용자가 존재하지 않음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_NOHOST

지정된 호스트가 존재하지 않음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_UNAVAILABLE

필수 서비스를 사용할 수 없음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_SOFTWARE

내부 소프트웨어 에러가 감지되었음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_OSERR

포크 하거나 파이프를 만들 수 없는 등, 운영 체제 에러가 감지되었음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_OSFILE

일부 시스템 파일이 없거나, 열 수 없거나, 다른 에러가 있음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_CANTCREAT

사용자가 지정한 출력 파일을 만들 수 없음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_IOERR

일부 파일에서 I/O를 수행하는 동안 에러가 발생했음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_TEMPFAIL

임시 에러가 발생했음을 나타내는 종료 코드. 이는 재시도 가능한 작업 중에 만들 수 없었던 네트워크 연결과 같이 실제로는 에러가 아닐 수 있는 것을 나타냅니다.

Availability: Unix, not WASI.

os.EX_PROTOCOL

프로토콜 교환이 불법이거나 유효하지 않거나 이해되지 않았음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_NOPERM

작업을 수행할 수 있는 권한이 충분하지 않음을 나타내는 종료 코드 (파일 시스템 문제에는 사용하지 않습니다).

Availability: Unix, not WASI.

os.EX_CONFIG

어떤 종류의 구성 에러가 발생했음을 나타내는 종료 코드.

Availability: Unix, not WASI.

os.EX_NOTFOUND

“항목을 찾을 수 없습니다” 와 같은 것을 의미하는 종료 코드.

Availability: Unix, not WASI.

os.fork()

자식 프로세스를 포크 합니다. 자식에서는 0을 반환하고, 부모에서는 자식의 프로세스 ID를 반환합니다. 에러가 발생하면 OSError를 일으킵니다.

FreeBSD <= 6.3 및 Cygwin을 포함한 일부 플랫폼은 스레드에서 fork()를 사용할 때 알려진 문제점이 있습니다.

인자 없이 감사 이벤트(auditing event) os.fork를 발생시킵니다.

경고

If you use TLS sockets in an application calling fork(), see the warning in the ssl documentation.

경고

On macOS the use of this function is unsafe when mixed with using higher-level system APIs, and that includes using urllib.request.

버전 3.8에서 변경: 서브 인터프리터에서 fork()를 호출하는 것은 더는 지원되지 않습니다 (RuntimeError가 발생합니다).

버전 3.12에서 변경: If Python is able to detect that your process has multiple threads, os.fork() now raises a DeprecationWarning.

We chose to surface this as a warning, when detectable, to better inform developers of a design problem that the POSIX platform specifically notes as not supported. Even in code that appears to work, it has never been safe to mix threading with os.fork() on POSIX platforms. The CPython runtime itself has always made API calls that are not safe for use in the child process when threads existed in the parent (such as malloc and free).

Users of macOS or users of libc or malloc implementations other than those typically found in glibc to date are among those already more likely to experience deadlocks running such code.

See this discussion on fork being incompatible with threads [https://discuss.python.org/t/33555] for technical details of why we’re surfacing this longstanding platform compatibility problem to developers.

Availability: POSIX, not WASI, not Android, not iOS.

os.forkpty()

새 의사 터미널을 자식의 제어 터미널로 사용하여 자식 프로세스를 포크 합니다. (pid, fd) 쌍을 반환하는데, 여기서 pid 는 자식에서 0이고, 부모에서는 새 자식의 프로세스 ID이고, fd 는 의사 터미널의 마스터 단의 파일 기술자입니다. 좀 더 이식성 있는 접근법을 사용하려면, pty 모듈을 사용하십시오. 에러가 발생하면 OSError를 일으킵니다.

인자 없이 감사 이벤트(auditing event) os.forkpty를 발생시킵니다.

경고

On macOS the use of this function is unsafe when mixed with using higher-level system APIs, and that includes using urllib.request.

버전 3.8에서 변경: 서브 인터프리터에서 forkpty()를 호출하는 것은 더는 지원되지 않습니다 (RuntimeError가 발생합니다).

버전 3.12에서 변경: If Python is able to detect that your process has multiple threads, this now raises a DeprecationWarning. See the longer explanation on os.fork().

Availability: Unix, not WASI, not Android, not iOS.

os.kill(pid, sig, /)

프로세스 pid에 시그널 sig를 보냅니다. 호스트 플랫폼에서 사용할 수 있는 구체적인 시그널에 대한 상수는 signal 모듈에 정의되어 있습니다.

Windows: The signal.CTRL_C_EVENT and signal.CTRL_BREAK_EVENT signals are special signals which can only be sent to console processes which share a common console window, e.g., some subprocesses. Any other value for sig will cause the process to be unconditionally killed by the TerminateProcess API, and the exit code will be set to sig.

signal.pthread_kill()도 참조하십시오.

pid, sig를 인자로 감사 이벤트(auditing event) os.kill을 발생시킵니다.

Availability: Unix, Windows, not WASI, not iOS.

버전 3.2에서 변경: 윈도우 지원이 추가되었습니다.

os.killpg(pgid, sig, /)

시그널 sig 를 프로세스 그룹 pgid 로 보냅니다.

pgid, sig를 인자로 감사 이벤트(auditing event) os.killpg를 발생시킵니다.

Availability: Unix, not WASI, not iOS.

os.nice(increment, /)

프로세스의 “우선도(niceness)”에 increment 를 추가합니다. 새로운 우선도를 반환합니다.

Availability: Unix, not WASI.

os.pidfd_open(pid, flags=0)

Return a file descriptor referring to the process pid with flags set. This descriptor can be used to perform process management without races and signals.

자세한 내용은 pidfd_open(2) [https://manpages.debian.org/pidfd_open(2)] 매뉴얼 페이지를 참조하십시오.

Availability: Linux >= 5.3, Android >= build-time API level 31

Added in version 3.9.

os.PIDFD_NONBLOCK

This flag indicates that the file descriptor will be non-blocking. If the process referred to by the file descriptor has not yet terminated, then an attempt to wait on the file descriptor using waitid(2) [https://manpages.debian.org/waitid(2)] will immediately return the error EAGAIN rather than blocking.

Availability: Linux >= 5.10

Added in version 3.12.

os.plock(op, /)

프로그램 세그먼트를 메모리에 잠급니다. (<sys/lock.h>에서 정의된) op 값은 잠기는 세그먼트를 판별합니다.

Availability: Unix, not WASI, not iOS.

os.popen(cmd, mode='r', buffering=-1)

Open a pipe to or from command cmd. The return value is an open file object connected to the pipe, which can be read or written depending on whether mode is 'r' (default) or 'w'. The buffering argument have the same meaning as the corresponding argument to the built-in open() function. The returned file object reads or writes text strings rather than bytes.

close 메서드는 자식 프로세스가 성공적으로 종료되면 None을 반환하고, 에러가 있으면 자식 프로세스가 반환한 코드를 반환합니다. POSIX 시스템에서, 반환 코드가 양수면, 프로세스의 반환 값을 1바이트 왼쪽으로 시프트 한 값을 나타냅니다. 반환 코드가 음수면, 음의 반환 코드로 주어진 시그널에 의해 강제 종료된 것입니다. 예를 들어, 자식 프로세스가 죽었을(kill) 때 반환 값은 - signal.SIGKILL 일 수 있습니다. 윈도우 시스템에서, 반환 값은 자식 프로세스의 부호 있는 정수 반환 코드를 포함합니다.

유닉스에서, waitstatus_to_exitcode()는 None이 아닐 때 close 메서드 결과(종료 상태)를 종료 코드로 변환하는 데 사용할 수 있습니다. 윈도우에서, close 메서드 결과는 직접 종료 코드(또는 None)입니다.

이것은 subprocess.Popen를 사용하여 구현됩니다; 자식 프로세스를 관리하고 통신하는 보다 강력한 방법에 대해서는 이 클래스의 설명서를 참조하십시오.

Availability: not WASI, not Android, not iOS.

참고

The Python UTF-8 Mode affects encodings used for cmd and pipe contents.

popen() is a simple wrapper around subprocess.Popen. Use subprocess.Popen or subprocess.run() to control options like encodings.

버전 3.14부터 폐지됨: The function is soft deprecated and should no longer be used to write new code. The subprocess module is recommended instead.

os.posix_spawn(path, argv, env, *, file_actions=None, setpgroup=None, resetids=False, setsid=False, setsigmask=(), setsigdef=(), scheduler=None)

Wraps the posix_spawn() C library API for use from Python.

대부분 사용자는 posix_spawn() 대신 subprocess.run()을 사용해야 합니다.

The positional-only arguments path, args, and env are similar to execve(). env is allowed to be None, in which case current process’ environment is used.

path 매개 변수는 실행 파일의 경로입니다. path에는 디렉터리가 있어야 합니다. 디렉터리 없이 실행 파일을 전달하려면 posix_spawnp()를 사용하십시오.

file_actions 인자는 C 라이브러리 구현의 fork()와 exec() 단계 사이의 자식 프로세스에서 특정 파일 기술자에 취할 동작을 설명하는 튜플의 시퀀스 일 수 있습니다. 각 튜플의 첫 번째 항목은 나머지 튜플 요소를 설명하는, 아래에 나열된 세 가지 형 지시자 중 하나여야 합니다:

os.POSIX_SPAWN_OPEN

(os.POSIX_SPAWN_OPEN, fd, path, flags, mode)

os.dup2(os.open(path, flags, mode), fd)를 수행합니다.

os.POSIX_SPAWN_CLOSE

(os.POSIX_SPAWN_CLOSE, fd)

os.close(fd)를 수행합니다.

os.POSIX_SPAWN_DUP2

(os.POSIX_SPAWN_DUP2, fd, new_fd)

os.dup2(fd, new_fd)를 수행합니다.

os.POSIX_SPAWN_CLOSEFROM

(os.POSIX_SPAWN_CLOSEFROM, fd)

Performs os.closerange(fd, INF).

These tuples correspond to the C library posix_spawn_file_actions_addopen(), posix_spawn_file_actions_addclose(), posix_spawn_file_actions_adddup2(), and posix_spawn_file_actions_addclosefrom_np() API calls used to prepare for the posix_spawn() call itself.

The setpgroup argument will set the process group of the child to the value specified. If the value specified is 0, the child’s process group ID will be made the same as its process ID. If the value of setpgroup is not set, the child will inherit the parent’s process group ID. This argument corresponds to the C library POSIX_SPAWN_SETPGROUP flag.

If the resetids argument is True it will reset the effective UID and GID of the child to the real UID and GID of the parent process. If the argument is False, then the child retains the effective UID and GID of the parent. In either case, if the set-user-ID and set-group-ID permission bits are enabled on the executable file, their effect will override the setting of the effective UID and GID. This argument corresponds to the C library POSIX_SPAWN_RESETIDS flag.

If the setsid argument is True, it will create a new session ID for posix_spawn. setsid requires POSIX_SPAWN_SETSID or POSIX_SPAWN_SETSID_NP flag. Otherwise, NotImplementedError is raised.

The setsigmask argument will set the signal mask to the signal set specified. If the parameter is not used, then the child inherits the parent’s signal mask. This argument corresponds to the C library POSIX_SPAWN_SETSIGMASK flag.

The sigdef argument will reset the disposition of all signals in the set specified. This argument corresponds to the C library POSIX_SPAWN_SETSIGDEF flag.

The scheduler argument must be a tuple containing the (optional) scheduler policy and an instance of sched_param with the scheduler parameters. A value of None in the place of the scheduler policy indicates that is not being provided. This argument is a combination of the C library POSIX_SPAWN_SETSCHEDPARAM and POSIX_SPAWN_SETSCHEDULER flags.

path, argv, env를 인자로 감사 이벤트(auditing event) os.posix_spawn을 발생시킵니다.

Added in version 3.8.

버전 3.13에서 변경: env parameter accepts None. os.POSIX_SPAWN_CLOSEFROM is available on platforms where posix_spawn_file_actions_addclosefrom_np() exists.

Availability: Unix, not WASI, not Android, not iOS.

os.posix_spawnp(path, argv, env, *, file_actions=None, setpgroup=None, resetids=False, setsid=False, setsigmask=(), setsigdef=(), scheduler=None)

Wraps the posix_spawnp() C library API for use from Python.

시스템이 (execvp(3)과 같은 방식으로) PATH 환경 변수에 의해 지정된 디렉터리 목록에서 실행 파일을 검색한다는 점을 제외하고는 posix_spawn()과 유사합니다.

path, argv, env를 인자로 감사 이벤트(auditing event) os.posix_spawn을 발생시킵니다.

Added in version 3.8.

Availability: POSIX, not WASI, not Android, not iOS.

See posix_spawn() documentation.

os.register_at_fork(*, before=None, after_in_parent=None, after_in_child=None)

os.fork() 또는 유사한 프로세스 복제 API를 사용하여 새 자식 프로세스가 포크 될 때 실행될 콜러블들을 등록합니다. 매개 변수는 선택적이며 키워드 전용입니다. 각각은 다른 호출 지점을 지정합니다.

before 는 자식 프로세스를 포크 하기 전에 호출되는 함수입니다.

after_in_parent 는 자식 프로세스를 포크 한 후에 부모 프로세스에서 호출되는 함수입니다.

after_in_child 는 자식 프로세스에서 호출되는 함수입니다.

이러한 호출은 제거가 파이썬 인터프리터로 반환될 것으로 예상되는 경우에만 수행됩니다. 일반적인 subprocess 실행은 자식이 인터프리터로 재진입하지 않기 때문에, 이 호출들이 일어나지 않습니다.

포크 이전에 실행되도록 등록된 함수는 등록 역순으로 실행됩니다. 포크 후에 실행되도록 등록된 함수(부모나 자식 모두)는 등록 순서로 호출됩니다.

제삼자 C 코드에 의한 fork() 호출은, 그것이 명시적으로 PyOS_BeforeFork(), PyOS_AfterFork_Parent() 및 PyOS_AfterFork_Child()를 호출하지 않는 한, 이 함수들을 호출하지 않습니다.

함수 등록을 취소할 방법은 없습니다.

Availability: Unix, not WASI, not Android, not iOS.

Added in version 3.7.

os.spawnl(mode, path, ...)

os.spawnle(mode, path, ..., env)

os.spawnlp(mode, file, ...)

os.spawnlpe(mode, file, ..., env)

os.spawnv(mode, path, args)

os.spawnve(mode, path, args, env)

os.spawnvp(mode, file, args)

os.spawnvpe(mode, file, args, env)

새 프로세스에서 프로그램 path 를 실행합니다.

(subprocess 모듈은 새 프로세스를 생성하고 결과를 조회하는데, 더욱 강력한 기능을 제공합니다; 이 모듈을 사용하는 것이 이 함수들을 사용하는 것보다 더 바람직합니다. 특히 이전 함수를 subprocess 모듈로 교체하기 섹션을 확인하십시오.)

mode 가 P_NOWAIT면, 이 함수는 새 프로세스의 프로세스 ID를 반환합니다; mode가 P_WAIT면, 종료 코드(정상적으로 종료했을 때)나 -signal(signal은 프로세스를 죽인 시그널입니다)을 반환합니다. 윈도우에서, 프로세스 ID는 실제로 프로세스 핸들이므로, waitpid() 함수에 사용할 수 있습니다.

VxWorks에서, 이 함수는 새로운 프로세스가 죽을(kill) 때 -signal을 반환하지 않습니다. 대신 OSError 예외가 발생합니다.

The “l” and “v” variants of the spawn* functions differ in how command-line arguments are passed. The “l” variants are perhaps the easiest to work with if the number of parameters is fixed when the code is written; the individual parameters simply become additional parameters to the spawnl*() functions. The “v” variants are good when the number of parameters is variable, with the arguments being passed in a list or tuple as the args parameter. In either case, the arguments to the child process must start with the name of the command being run.

끝 근처에 두 번째 “p”가 포함된 변형(spawnlp(), spawnlpe(), spawnvp() 및 spawnvpe())은 PATH 환경 변수를 사용하여 프로그램 file 을 찾습니다. 환경이 대체 될 때 (다음 단락에서 설명할 spawn*e 변형 중 하나를 사용하여), 새 환경이 PATH 변수의 소스로 사용됩니다. 다른 변형 spawnl(), spawnle(), spawnv() 및 spawnve()는 PATH 변수를 사용하여 실행 파일을 찾지 않습니다; path 에는 반드시 적절한 절대 또는 상대 경로가 있어야 합니다.

spawnle(), spawnlpe(), spawnve() 및 spawnvpe()의 경우 (모두 “e”로 끝납니다), env 매개 변수는 새 프로세스의 환경 변수를 정의하는 데 사용되는 매핑이어야 합니다 (이것이 현재 프로세스의 환경 대신 사용됩니다); 함수 spawnl(), spawnlp(), spawnv() 및 spawnvp()는 모두 새 프로세스가 현재 프로세스의 환경을 상속하게 합니다. env 딕셔너리의 키와 값은 반드시 문자열이어야 함에 주의하십시오; 잘못된 키나 값은 반환 값 127로 함수가 실패하게 합니다.

예를 들어, spawnlp() 및 spawnvpe()에 대한 다음 호출은 동등합니다:

import os
os.spawnlp(os.P_WAIT, 'cp', 'cp', 'index.html', '/dev/null')

L = ['cp', 'index.html', '/dev/null']
os.spawnvpe(os.P_WAIT, 'cp', L, os.environ)

mode, path, args, env를 인자로 감사 이벤트(auditing event) os.spawn을 발생시킵니다.

Availability: Unix, Windows, not WASI, not Android, not iOS.

spawnlp(), spawnlpe(), spawnvp() and spawnvpe() are not available on Windows. spawnle() and spawnve() are not thread-safe on Windows; we advise you to use the subprocess module instead.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.14부터 폐지됨: These functions are soft deprecated and should no longer be used to write new code. The subprocess module is recommended instead.

os.P_NOWAIT

os.P_NOWAITO

Possible values for the mode parameter to the spawn* family of functions. If either of these values is given, the spawn* functions will return as soon as the new process has been created, with the process id as the return value.

Availability: Unix, Windows.

os.P_WAIT

Possible value for the mode parameter to the spawn* family of functions. If this is given as mode, the spawn* functions will not return until the new process has run to completion and will return the exit code of the process the run is successful, or -signal if a signal kills the process.

Availability: Unix, Windows.

os.P_DETACH

os.P_OVERLAY

spawn* 계열 함수의 mode 매개 변수에 사용할 수 있는 값. 이들은 위에 나열된 것보다 이식성이 낮습니다. P_DETACH는 P_NOWAIT와 비슷하지만, 새 프로세스는 호출 프로세스의 콘솔에서 분리됩니다. P_OVERLAY가 사용되면, 현재 프로세스가 대체됩니다; spawn* 함수가 반환되지 않습니다.

Availability: Windows.

os.startfile(path[, operation][, arguments][, cwd][, show_cmd])

연관된 응용 프로그램으로 파일을 시작합니다.

When operation is not specified, this acts like double-clicking the file in Windows Explorer, or giving the file name as an argument to the start command from the interactive command shell: the file is opened with whatever application (if any) its extension is associated.

When another operation is given, it must be a “command verb” that specifies what should be done with the file. Common verbs documented by Microsoft are 'open', 'print' and 'edit' (to be used on files) as well as 'explore' and 'find' (to be used on directories).

When launching an application, specify arguments to be passed as a single string. This argument may have no effect when using this function to launch a document.

The default working directory is inherited, but may be overridden by the cwd argument. This should be an absolute path. A relative path will be resolved against this argument.

Use show_cmd to override the default window style. Whether this has any effect will depend on the application being launched. Values are integers as supported by the Win32 ShellExecute() function.

startfile() returns as soon as the associated application is launched. There is no option to wait for the application to close, and no way to retrieve the application’s exit status. The path parameter is relative to the current directory or cwd. If you want to use an absolute path, make sure the first character is not a slash ('/') Use pathlib or the os.path.normpath() function to ensure that paths are properly encoded for Win32.

To reduce interpreter startup overhead, the Win32 ShellExecute() function is not resolved until this function is first called. If the function cannot be resolved, NotImplementedError will be raised.

path, operation을 인자로 감사 이벤트(auditing event) os.startfile을 발생시킵니다.

Raises an auditing event os.startfile/2 with arguments path, operation, arguments, cwd, show_cmd.

Availability: Windows.

버전 3.10에서 변경: Added the arguments, cwd and show_cmd arguments, and the os.startfile/2 audit event.

os.system(command)

Execute the command (a string) in a subshell. This is implemented by calling the Standard C function system(), and has the same limitations. Changes to sys.stdin, etc. are not reflected in the environment of the executed command. If command generates any output, it will be sent to the interpreter standard output stream. The C standard does not specify the meaning of the return value of the C function, so the return value of the Python function is system-dependent.

On Unix, the return value is the exit status of the process encoded in the format specified for wait().

윈도우에서, 반환 값은 command를 실행한 후 시스템 셸에서 반환한 값입니다. 셸은 윈도우 환경 변수 COMSPEC에 의해 제공됩니다: 보통 cmd.exe인데, 명령 실행의 종료 상태를 반환합니다; 기본이 아닌 셸을 사용하는 시스템에서는 셸 설명서를 참조하십시오.

The subprocess module provides more powerful facilities for spawning new processes and retrieving their results; using that module is recommended to using this function. See the 이전 함수를 subprocess 모듈로 교체하기 section in the subprocess documentation for some helpful recipes.

유닉스에서, waitstatus_to_exitcode()를 사용하여 결과(종료 상태)를 종료 코드로 변환할 수 있습니다. 윈도우에서, 결과는 직접 종료 코드입니다.

command를 인자로 감사 이벤트(auditing event) os.system을 발생시킵니다.

Availability: Unix, Windows, not WASI, not Android, not iOS.

os.times()

현재 전역 프로세스 시간을 반환합니다. 반환 값은 5가지 어트리뷰트를 가진 객체입니다:

user - user time

system - system time

children_user - user time of all child processes

children_system - system time of all child processes

elapsed - elapsed real time since a fixed point in the past

For backwards compatibility, this object also behaves like a five-tuple containing user, system, children_user, children_system, and elapsed in that order.

See the Unix manual page times(2) [https://manpages.debian.org/times(2)] and times(3) [https://man.freebsd.org/cgi/man.cgi?time(3)] manual page on Unix or the GetProcessTimes MSDN [https://docs.microsoft.com/windows/win32/api/processthreadsapi/nf-processthreadsapi-getprocesstimes] on Windows. On Windows, only user and system are known; the other attributes are zero.

Availability: Unix, Windows.

버전 3.3에서 변경: 반환형이 튜플에서 이름이 지정된 어트리뷰트를 가진 튜플류 객체로 변경되었습니다.

os.wait()

자식 프로세스가 완료될 때까지 기다렸다가, pid 및 종료 상태 표시를 포함하는 튜플을 반환합니다: 종료 상태 표시는 16비트 숫자인데, 하위 바이트가 프로세스를 죽인 시그널 번호이고, 상위 바이트가 종료 상태(시그널 번호가 0이면)입니다; 코어 파일이 생성되면 하위 바이트의 상위 비트가 설정됩니다.

If there are no children that could be waited for, ChildProcessError is raised.

waitstatus_to_exitcode()를 사용하여 종료 상태를 종료 코드로 변환할 수 있습니다.

Availability: Unix, not WASI, not Android, not iOS.

더 보기

The other wait*() functions documented below can be used to wait for the completion of a specific child process and have more options. waitpid() is the only one also available on Windows.

os.waitid(idtype, id, options, /)

Wait for the completion of a child process.

idtype can be P_PID, P_PGID, P_ALL, or (on Linux) P_PIDFD. The interpretation of id depends on it; see their individual descriptions.

options is an OR combination of flags. At least one of WEXITED, WSTOPPED or WCONTINUED is required; WNOHANG and WNOWAIT are additional optional flags.

The return value is an object representing the data contained in the siginfo_t structure with the following attributes:

si_pid (process ID)

si_uid (real user ID of the child)

si_signo (always SIGCHLD)

si_status (the exit status or signal number, depending on si_code)

si_code (see CLD_EXITED for possible values)

If WNOHANG is specified and there are no matching children in the requested state, None is returned. Otherwise, if there are no matching children that could be waited for, ChildProcessError is raised.

Availability: Unix, not WASI, not Android, not iOS.

Added in version 3.3.

버전 3.13에서 변경: This function is now available on macOS as well.

os.waitpid(pid, options, /)

이 함수의 세부 사항은 유닉스 및 윈도우에서 다릅니다.

유닉스에서: 프로세스 ID pid에 의해 주어진 자식 프로세스의 완료를 기다리고, 프로세스 ID와 종료 상태 표시(wait()처럼 인코딩됨)를 포함하는 튜플을 반환합니다. 호출의 의미는 정수 options 의 값에 영향을 받는데, 일반 작업의 경우 0 이어야 합니다.

pid 가 0보다 크면, waitpid()는 해당 프로세스에 대한 상태 정보를 요청합니다. pid 가 0이면, 현재 프로세스의 프로세스 그룹에 있는 모든 자식의 상태를 요청합니다. pid 가 -1이면, 현재 프로세스의 모든 자식의 상태를 요청합니다. pid 가 -1보다 작으면, 프로세스 그룹 -pid(pid 의 절댓값)에 있는 모든 프로세스의 상태를 요청합니다.

options is an OR combination of flags. If it contains WNOHANG and there are no matching children in the requested state, (0, 0) is returned. Otherwise, if there are no matching children that could be waited for, ChildProcessError is raised. Other options that can be used are WUNTRACED and WCONTINUED.

윈도우에서: 프로세스 핸들 pid로 지정된 프로세스가 완료될 때까지 기다리고, pid와 종료 상태를 8비트 왼쪽으로 시프트 한 값을 포함하는 튜플을 반환합니다 (시프팅이 함수를 더 이식성 있게 만듭니다). 0보다 작거나 같은 pid 는 윈도우에서 특별한 의미가 없고 예외가 발생합니다. 정수 options 의 값은 아무 효과가 없습니다. pid 는 id가 알려진 모든 프로세스를 가리킬 수 있습니다, 반드시 자식 프로세스일 필요는 없습니다. P_NOWAIT로 호출된 spawn* 함수는 적절한 프로세스 핸들을 반환합니다.

waitstatus_to_exitcode()를 사용하여 종료 상태를 종료 코드로 변환할 수 있습니다.

Availability: Unix, Windows, not WASI, not Android, not iOS.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 함수는 이제 InterruptedError 예외를 일으키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하세요).

os.wait3(options)

Similar to waitpid(), except no process id argument is given and a 3-element tuple containing the child’s process id, exit status indication, and resource usage information is returned. Refer to resource.getrusage() for details on resource usage information. The options argument is the same as that provided to waitpid() and wait4().

waitstatus_to_exitcode()를 사용하여 종료 상태를 종료 코드로 변환할 수 있습니다.

Availability: Unix, not WASI, not Android, not iOS.

os.wait4(pid, options)

Similar to waitpid(), except a 3-element tuple, containing the child’s process id, exit status indication, and resource usage information is returned. Refer to resource.getrusage() for details on resource usage information. The arguments to wait4() are the same as those provided to waitpid().

waitstatus_to_exitcode()를 사용하여 종료 상태를 종료 코드로 변환할 수 있습니다.

Availability: Unix, not WASI, not Android, not iOS.

os.P_PID

os.P_PGID

os.P_ALL

os.P_PIDFD

These are the possible values for idtype in waitid(). They affect how id is interpreted:

P_PID - wait for the child whose PID is id.

P_PGID - wait for any child whose progress group ID is id.

P_ALL - wait for any child; id is ignored.

P_PIDFD - wait for the child identified by the file descriptor id (a process file descriptor created with pidfd_open()).

Availability: Unix, not WASI, not Android, not iOS.

참고

P_PIDFD is only available on Linux >= 5.4.

Added in version 3.3.

Added in version 3.9: The P_PIDFD constant.

os.WCONTINUED

This options flag for waitpid(), wait3(), wait4(), and waitid() causes child processes to be reported if they have been continued from a job control stop since they were last reported.

Availability: Unix, not WASI, not Android, not iOS.

os.WEXITED

This options flag for waitid() causes child processes that have terminated to be reported.

The other wait* functions always report children that have terminated, so this option is not available for them.

Availability: Unix, not WASI, not Android, not iOS.

Added in version 3.3.

os.WSTOPPED

This options flag for waitid() causes child processes that have been stopped by the delivery of a signal to be reported.

This option is not available for the other wait* functions.

Availability: Unix, not WASI, not Android, not iOS.

Added in version 3.3.

os.WUNTRACED

This options flag for waitpid(), wait3(), and wait4() causes child processes to also be reported if they have been stopped but their current state has not been reported since they were stopped.

This option is not available for waitid().

Availability: Unix, not WASI, not Android, not iOS.

os.WNOHANG

This options flag causes waitpid(), wait3(), wait4(), and waitid() to return right away if no child process status is available immediately.

Availability: Unix, not WASI, not Android, not iOS.

os.WNOWAIT

This options flag causes waitid() to leave the child in a waitable state, so that a later wait*() call can be used to retrieve the child status information again.

This option is not available for the other wait* functions.

Availability: Unix, not WASI, not Android, not iOS.

os.CLD_EXITED

os.CLD_KILLED

os.CLD_DUMPED

os.CLD_TRAPPED

os.CLD_STOPPED

os.CLD_CONTINUED

These are the possible values for si_code in the result returned by waitid().

Availability: Unix, not WASI, not Android, not iOS.

Added in version 3.3.

버전 3.9에서 변경: CLD_KILLED와 CLD_STOPPED 값을 추가했습니다.

os.waitstatus_to_exitcode(status)

대기 상태(wait status)를 종료 코드로 변환합니다.

유닉스에서:

프로세스가 정상적으로 종료되면 (WIFEXITED(status)가 참이면), 프로세스 종료 상태를 반환합니다 (WEXITSTATUS(status)를 반환합니다): 결과는 0보다 크거나 같습니다.

프로세스가 시그널에 의해 종료되면 (WIFSIGNALED(status)가 참이면), -signum을 반환합니다, 여기서 signum은 프로세스를 종료시킨 시그널 번호입니다 (-WTERMSIG(status)를 반환합니다): 결과는 0보다 작습니다.

그렇지 않으면, ValueError를 발생시킵니다.

윈도우에서, 8비트만큼 오른쪽으로 시프트된 status를 반환합니다.

유닉스에서, 프로세스가 추적되고 있거나 waitpid()가 WUNTRACED 옵션으로 호출되었으면, 호출자는 먼저 WIFSTOPPED(status)가 참인지 확인해야 합니다. WIFSTOPPED(status)가 참이면 이 함수를 호출하면 안 됩니다.

더 보기

WIFEXITED(), WEXITSTATUS(), WIFSIGNALED(), WTERMSIG(), WIFSTOPPED(), WSTOPSIG() 함수.

Availability: Unix, Windows, not WASI, not Android, not iOS.

Added in version 3.9.

다음 함수들은 system(), wait() 또는 waitpid()에 의해 반환된 프로세스 상태 코드를 매개 변수로 받아들입니다. 이것들은 프로세스의 처리를 결정하는 데 사용될 수 있습니다.

os.WCOREDUMP(status, /)

프로세스에 대해 코어 덤프가 생성되었으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

이 함수는 WIFSIGNALED()가 참일 때만 사용해야 합니다.

Availability: Unix, not WASI, not Android, not iOS.

os.WIFCONTINUED(status)

Return True if a stopped child has been resumed by delivery of SIGCONT (if the process has been continued from a job control stop), otherwise return False.

WCONTINUED 옵션을 참조하십시오.

Availability: Unix, not WASI, not Android, not iOS.

os.WIFSTOPPED(status)

시그널의 전달로 인해 프로세스가 중지되었으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

WIFSTOPPED()는 WUNTRACED 옵션을 사용하여 waitpid()을 호출했거나 프로세스가 추적되고 있을 때만 True를 반환합니다 (ptrace(2) [https://manpages.debian.org/ptrace(2)]를 참조하십시오).

Availability: Unix, not WASI, not Android, not iOS.

os.WIFSIGNALED(status)

시그널로 인해 프로세스가 종료되었으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

Availability: Unix, not WASI, not Android, not iOS.

os.WIFEXITED(status)

프로세스가 정상 종료했으면 True를 반환합니다, 즉 exit()나 _exit()를 호출했거나, main()에서 반환하여; 그렇지 않으면 False를 반환합니다.

Availability: Unix, not WASI, not Android, not iOS.

os.WEXITSTATUS(status)

프로세스 종료 상태를 반환합니다.

이 함수는 WIFEXITED()가 참일 때만 사용해야 합니다.

Availability: Unix, not WASI, not Android, not iOS.

os.WSTOPSIG(status)

프로세스를 멈추게 한 시그널을 반환합니다.

이 함수는 WIFSTOPPED()가 참일 때만 사용해야 합니다.

Availability: Unix, not WASI, not Android, not iOS.

os.WTERMSIG(status)

프로세스를 종료시킨 시그널의 번호를 반환합니다.

이 함수는 WIFSIGNALED()가 참일 때만 사용해야 합니다.

Availability: Unix, not WASI, not Android, not iOS.

스케줄러에 대한 인터페이스

이 함수들은 운영 체제가 프로세스에 CPU 시간을 할당하는 방법을 제어합니다. 일부 유닉스 플랫폼에서만 사용할 수 있습니다. 자세한 내용은 유닉스 매뉴얼 페이지를 참조하십시오.

Added in version 3.3.

다음 스케줄 정책은 운영 체제에서 지원하는 경우 공개됩니다.

os.SCHED_OTHER

기본 스케줄 정책.

os.SCHED_BATCH

컴퓨터의 나머지 부분에서 반응성을 유지하려고 하는 CPU 집약적인 프로세스를 위한 스케줄 정책.

os.SCHED_IDLE

매우 낮은 우선순위의 배경 작업에 대한 스케줄 정책.

os.SCHED_SPORADIC

간헐적인 서버 프로그램을 위한 스케줄 정책.

os.SCHED_FIFO

선입 선출 (First In First Out) 스케줄 정책.

os.SCHED_RR

라운드 로빈 스케줄 정책.

os.SCHED_RESET_ON_FORK

이 플래그는 다른 스케줄 정책과 OR 될 수 있습니다. 이 플래그가 설정되어있는 프로세스가 포크 할 때, 자식의 스케줄링 정책 및 우선순위가 기본값으로 재설정됩니다.

class os.sched_param(sched_priority)

이 클래스는 sched_setparam(), sched_setscheduler(), 및 sched_getparam()에서 사용되는 튜닝 가능한 스케줄 파라미터를 나타냅니다. 불변입니다.

현재, 가능한 매개 변수는 하나뿐입니다:

sched_priority

스케줄 정책의 스케줄 우선순위.

os.sched_get_priority_min(policy)

policy의 최소 우선순위 값을 가져옵니다. policy 는 위의 스케줄 정책 상수 중 하나입니다.

os.sched_get_priority_max(policy)

policy의 최대 우선순위 값을 가져옵니다. policy 는 위의 스케줄 정책 상수 중 하나입니다.

os.sched_setscheduler(pid, policy, param, /)

PID가 pid인 프로세스의 스케줄 정책을 설정합니다. pid 가 0이면, 호출하는 프로세스를 의미합니다. policy 는 위의 스케줄 정책 상수 중 하나입니다. param 은 sched_param 인스턴스입니다.

os.sched_getscheduler(pid, /)

PID가 pid인 프로세스의 스케줄 정책을 반환합니다. pid 가 0이면, 호출하는 프로세스를 의미합니다. 결과는 위의 스케줄 정책 상수 중 하나입니다.

os.sched_setparam(pid, param, /)

Set the scheduling parameters for the process with PID pid. A pid of 0 means the calling process. param is a sched_param instance.

os.sched_getparam(pid, /)

PID가 pid인 프로세스의 스케줄 매개 변수를 sched_param 인스턴스로 반환합니다. pid 가 0이면 호출하는 프로세스를 의미합니다.

os.sched_rr_get_interval(pid, /)

PID가 pid인 프로세스의 라운드 로빈 퀀텀을 초 단위로 반환합니다. pid 가 0이면 호출하는 프로세스를 의미합니다.

os.sched_yield()

자발적으로 CPU를 양도합니다.

os.sched_setaffinity(pid, mask, /)

PID가 pid인 프로세스(또는 0이면 현재 프로세스)를 CPU 집합으로 제한합니다. mask 는 프로세스가 제한되어야 하는 CPU 집합을 나타내는 정수의 이터러블입니다.

os.sched_getaffinity(pid, /)

Return the set of CPUs the process with PID pid is restricted to.

If pid is zero, return the set of CPUs the calling thread of the current process is restricted to.

See also the process_cpu_count() function.

기타 시스템 정보

os.confstr(name, /)

문자열 값 시스템 구성 값을 반환합니다. name 은 조회할 구성 값을 지정합니다; 정의된 시스템 값의 이름인 문자열일 수 있습니다; 이 이름은 여러 표준(POSIX, 유닉스 95, 유닉스 98 및 기타)에서 지정됩니다. 일부 플랫폼은 추가 이름도 정의합니다. 호스트 운영 체제에 알려진 이름은 confstr_names 딕셔너리의 키로 제공됩니다. 해당 매핑에 포함되지 않은 구성 변수를 위해, name에 정수를 전달하는 것도 허용됩니다.

name 으로 지정된 구성 값이 정의되어 있지 않으면, None이 반환됩니다.

name 이 문자열이고 알 수 없으면, ValueError가 발생합니다. name에 대한 특정 값이 호스트 시스템에서 지원되지 않으면, confstr_names에 포함되어 있어도, 에러 번호 errno.EINVAL로 OSError가 발생합니다.

Availability: Unix.

os.confstr_names

confstr()에서 허용하는 이름을 호스트 운영 체제가 해당 이름에 대해 정의한 정숫값으로 매핑하는 딕셔너리입니다. 이것은 시스템에 알려진 이름 집합을 판별하는 데 사용될 수 있습니다.

Availability: Unix.

os.cpu_count()

Return the number of logical CPUs in the system. Returns None if undetermined.

The process_cpu_count() function can be used to get the number of logical CPUs usable by the calling thread of the current process.

Added in version 3.4.

버전 3.13에서 변경: If -X cpu_count is given or PYTHON_CPU_COUNT is set, cpu_count() returns the overridden value n.

os.getloadavg()

마지막 1, 5, 15분에 걸쳐 평균한 시스템 실행 대기열의 프로세스 수를 반환하거나, 로드 평균을 얻을 수 없으면, OSError를 발생시킵니다.

Availability: Unix.

os.process_cpu_count()

Get the number of logical CPUs usable by the calling thread of the current process. Returns None if undetermined. It can be less than cpu_count() depending on the CPU affinity.

The cpu_count() function can be used to get the number of logical CPUs in the system.

If -X cpu_count is given or PYTHON_CPU_COUNT is set, process_cpu_count() returns the overridden value n.

See also the sched_getaffinity() function.

Added in version 3.13.

os.sysconf(name, /)

정숫값 시스템 구성 값을 반환합니다. name 으로 지정된 구성 값이 정의되어 있지 않으면, -1이 반환됩니다. confstr()의 name 매개 변수에 관한 주석은 여기에도 적용됩니다; 알려진 이름에 대한 정보를 제공하는 딕셔너리는 sysconf_names에 의해 제공됩니다.

Availability: Unix.

os.sysconf_names

sysconf()에서 허용하는 이름을 호스트 운영 체제가 해당 이름에 대해 정의한 정숫값으로 매핑하는 딕셔너리입니다. 이것은 시스템에 알려진 이름 집합을 판별하는 데 사용될 수 있습니다.

Availability: Unix.

버전 3.11에서 변경: Add 'SC_MINSIGSTKSZ' name.

다음 데이터값들은 경로 조작 연산을 지원하는 데 사용됩니다. 이는 모든 플랫폼에서 정의됩니다.

경로명에 대한 고수준 연산은 os.path 모듈에서 정의됩니다.

os.curdir

현재 디렉터리를 가리키기 위해 운영 체제에서 사용하는 상수 문자열. 이것은 윈도우 및 POSIX의 경우 '.'입니다. os.path를 통해서도 제공됩니다.

os.pardir

부모 디렉터리를 가리키기 위해 운영 체제에서 사용하는 상수 문자열입니다. 이것은 윈도우 및 POSIX의 경우 '..'입니다. os.path를 통해서도 제공됩니다.

os.sep

경로명 구성 요소를 분리하기 위해 운영 체제에서 사용하는 문자. 이것은 POSIX의 경우 '/'이고, 윈도우의 경우 '\\'입니다. 이것을 아는 것만으로는 경로명을 구문 분석하거나 이어붙일 수는 없습니다만 — os.path.split()와 os.path.join()를 사용하세요 — 가끔 유용합니다. os.path를 통해서도 제공됩니다.

os.altsep

경로명 구성 요소를 분리하기 위해 운영 체제에서 사용하는 대체 문자이거나, 단 하나의 구분 문자만 있는 경우 None입니다. sep가 백 슬래시인 윈도우 시스템에서는 '/'로 설정됩니다. os.path를 통해서도 제공됩니다.

os.extsep

기본 파일명과 확장자를 구분하는 문자; 예를 들어, os.py에서 '.'. os.path를 통해서도 제공됩니다.

os.pathsep

검색 경로 구성 요소(PATH에서와 같이)를 분리하기 위해 운영 체제에서 관습적으로 사용하는 문자, 가령 POSIX의 ':' 또는 윈도우의 ';'. os.path를 통해서도 제공됩니다.

os.defpath

환경에 'PATH' 키가 없을 때, exec*p* 및 spawn*p*에서 사용하는 기본 검색 경로. os.path를 통해서도 제공됩니다.

os.linesep

현재 플랫폼에서 행을 분리(또는 종료)하는 데 사용되는 문자열. 이는 POSIX의 '\n'와 같은 단일 문자이거나, 윈도우의 '\r\n'와 같은 여러 문자일 수 있습니다. 텍스트 모드로 열린(기본값) 파일에 쓸 때 줄 종결자로 os.linesep를 사용하지 마십시오; 대신 모든 플랫폼에서 단일 '\n'를 사용하십시오.

os.devnull

널(null) 장치의 파일 경로. 예를 들어: POSIX의 경우 '/dev/null', 윈도우의 경우 'nul'. os.path를 통해서도 제공됩니다.

os.RTLD_LAZY

os.RTLD_NOW

os.RTLD_GLOBAL

os.RTLD_LOCAL

os.RTLD_NODELETE

os.RTLD_NOLOAD

os.RTLD_DEEPBIND

setdlopenflags() 및 getdlopenflags() 함수에 사용하는 플래그. 각 플래그가 의미하는 바는 유닉스 매뉴얼 페이지 dlopen(3) [https://manpages.debian.org/dlopen(3)]를 참조하십시오.

Added in version 3.3.

난수

os.getrandom(size, flags=0)

최대 size 크기의 난수 바이트열을 업습니다. 이 함수는 요청한 것보다 짧은 바이트열를 반환할 수 있습니다.

이 바이트열은 사용자 공간 난수 발생기를 시드 하거나 암호화 목적으로 사용할 수 있습니다.

getrandom()는 장치 드라이버 및 기타 환경 소음원에서 수집한 엔트로피에 의존합니다. 대량의 데이터를 불필요하게 읽는 것은 /dev/random 및 /dev/urandom 장치의 다른 사용자에게 부정적인 영향을 미칩니다.

The flags argument is a bit mask that can contain zero or more of the following values ORed together: os.GRND_RANDOM and GRND_NONBLOCK.

See also the Linux getrandom() manual page [https://man7.org/linux/man-pages/man2/getrandom.2.html].

Availability: Linux >= 3.17.

Added in version 3.6.

os.urandom(size, /)

Return a bytestring of size random bytes suitable for cryptographic use.

이 함수는 OS 종속적인 임의성 소스에서 난수 바이트열을 반환합니다. 반환된 데이터는 암호화 응용에 충분하도록 예측할 수 없어야 하지만, 정확한 품질은 OS 구현에 따라 달라집니다.

리눅스에서, getrandom() 시스템 호출을 사용할 수 있으면, 블로킹 모드로 사용됩니다: 시스템의 urandom 엔트로피 풀이 초기화될 때까지 블록 됩니다 (커널이 128비트의 엔트로피를 수집합니다). 이유는 PEP 524 [https://peps.python.org/pep-0524/]를 참조하십시오. 리눅스에서, getrandom() 함수는 (GRND_NONBLOCK 플래그를 사용하여) 비 블로킹 모드로 난수 바이트열을 얻거나, 시스템 urandom 엔트로피 풀이 초기화될 때까지 폴링 할 수 있습니다.

유닉스류 시스템에서, /dev/urandom 장치에서 난수 바이트열을 읽습니다. /dev/urandom 장치를 사용할 수 없거나 읽을 수 없으면, NotImplementedError 예외가 발생합니다.

On Windows, it will use BCryptGenRandom().

더 보기

secrets 모듈은 고수준 함수를 제공합니다. 플랫폼에서 제공되는 난수 발생기에 대한 사용하기 쉬운 인터페이스는 random.SystemRandom를 참조하십시오.

버전 3.5에서 변경: 리눅스 3.17 및 이후 버전에서, 이제 getrandom() 시스템 호출을 사용할 수 있으면 사용합니다. OpenBSD 5.6 이상에서, C getentropy() 함수가 이제 사용됩니다. 이 함수들은 내부 파일 기술자의 사용을 피합니다.

버전 3.5.2에서 변경: 리눅스에서, getrandom() 시스템 호출이 블록 하면 (urandom 엔트로피 풀이 아직 초기화되지 않았으면), /dev/urandom을 읽는 것으로 대체됩니다.

버전 3.6에서 변경: 리눅스에서, getrandom()은 이제 보안을 강화하기 위해 블로킹 모드로 사용됩니다.

버전 3.11에서 변경: On Windows, BCryptGenRandom() is used instead of CryptGenRandom() which is deprecated.

os.GRND_NONBLOCK

기본적으로, /dev/random에서 읽을 때, getrandom()는 사용할 수 있는 난수 바이트열이 없으면 블록 하고, /dev/urandom에서 읽을 때는, 엔트로피 풀이 아직 초기화되지 않았으면 블록 합니다.

GRND_NONBLOCK 플래그가 설정되면, getrandom()는 이럴 때 블록 하지 않고, 대신 즉시 BlockingIOError를 발생시킵니다.

Added in version 3.6.

os.GRND_RANDOM

이 비트가 설정되면, /dev/urandom 풀 대신 /dev/random 풀에서 난수 바이트열을 얻습니다.

Added in version 3.6.

io — Core tools for working with streams

소스 코드: Lib/io.py [https://github.com/python/cpython/tree/main/Lib/io.py]

개요

io 모듈은 다양한 유형의 I/O를 처리하기 위한 파이썬의 주 장치를 제공합니다. I/O에는 세 가지 주요 유형이 있습니다: 텍스트(text) I/O, 바이너리(binary) I/O 및 원시(raw) I/O. 이들은 일반적인 범주이며 다양한 배경 저장소를 각각에 사용할 수 있습니다. 이러한 범주 중 하나에 속하는 구상 객체를 파일 객체라고 합니다. 다른 일반적인 용어는 스트림(stream)과 파일류 객체(file-like object)입니다.

범주와 상관없이, 각 구상 스트림 객체에는 다양한 기능이 있습니다: 읽기 전용, 쓰기 전용 또는 읽고-쓰기일 수 있습니다. 또한 임의의 무작위 액세스(임의의 위치로 전방이나 후방 탐색)를 허용하거나 순차적 액세스(예를 들어 소켓이나 파이프의 경우)만 허용할 수 있습니다.

All streams are careful about the type of data you give to them. For example giving a str object to the write() method of a binary stream will raise a TypeError. So will giving a bytes object to the write() method of a text stream.

버전 3.3에서 변경: IOError가 이제는 OSError의 별칭이라서, IOError를 발생시켰던 연산은 이제 OSError를 발생시킵니다.

텍스트 I/O

텍스트 I/O는 str 객체를 기대하고 생성합니다. 이는 배경 저장소가 네이티브 하게 바이트열로 구성되었을 때마다 (가령 파일의 경우), 플랫폼별 줄 넘김 문자의 선택적 변환뿐만 아니라 데이터의 인코딩과 디코딩이 투명하게 이루어짐을 의미합니다.

The easiest way to create a text stream is with open(), optionally specifying an encoding:

f = open("myfile.txt", "r", encoding="utf-8")

인 메모리 텍스트 스트림도 StringIO 객체로 제공됩니다:

f = io.StringIO("some initial text data")

텍스트 스트림 API는 TextIOBase의 설명서에 자세히 설명되어 있습니다.

바이너리 I/O

바이너리 I/O(버퍼링 된(buffered) I/O라고도 합니다)는 바이트열류 객체를 기대하고 bytes 객체를 생성합니다. 인코딩, 디코딩 또는 줄 넘김 변환이 수행되지 않습니다. 이 범주의 스트림은 모든 종류의 텍스트가 아닌 데이터에 사용할 수 있으며, 텍스트 데이터 처리를 수동으로 제어해야 할 때도 사용할 수 있습니다.

The easiest way to create a binary stream is with open() with 'b' in the mode string:

f = open("myfile.jpg", "rb")

인 메모리 바이너리 스트림도 BytesIO 객체로 제공됩니다:

f = io.BytesIO(b"some initial binary data: \x00\x01")

바이너리 스트림 API는 BufferedIOBase 설명서에 자세히 설명되어 있습니다.

다른 라이브러리 모듈은 텍스트나 바이너리 스트림을 만드는 다른 방법을 제공할 수 있습니다. 예를 들어 socket.socket.makefile()을 참조하십시오.

원시 I/O

원시 I/O(버퍼링 되지 않은(unbuffered) I/O라고도 합니다)는 일반적으로 바이너리와 텍스트 스트림을 위한 저수준 빌딩 블록으로 사용됩니다; 사용자 코드에서 원시 스트림을 직접 조작하는 것은 거의 유용하지 않습니다. 그런데도, 버퍼링을 비활성화해서 바이너리 모드로 파일을 열어 원시 스트림을 만들 수 있습니다:

f = open("myfile.jpg", "rb", buffering=0)

원시 스트림 API는 RawIOBase 설명서에 자세히 설명되어 있습니다.

Text Encoding

The default encoding of TextIOWrapper and open() is locale-specific (locale.getencoding()).

However, many developers forget to specify the encoding when opening text files encoded in UTF-8 (e.g. JSON, TOML, Markdown, etc…) since most Unix platforms use UTF-8 locale by default. This causes bugs because the locale encoding is not UTF-8 for most Windows users. For example:

# May not work on Windows when non-ASCII characters in the file.
with open("README.md") as f:
    long_description = f.read()

Accordingly, it is highly recommended that you specify the encoding explicitly when opening text files. If you want to use UTF-8, pass encoding="utf-8". To use the current locale encoding, encoding="locale" is supported since Python 3.10.

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Python UTF-8 Mode

Python UTF-8 Mode can be used to change the default encoding to UTF-8 from locale-specific encoding.

PEP 686 [https://peps.python.org/pep-0686/]

Python 3.15 will make Python UTF-8 Mode default.

Opt-in EncodingWarning

Added in version 3.10: See PEP 597 [https://peps.python.org/pep-0597/] for more details.

To find where the default locale encoding is used, you can enable the -X warn_default_encoding command line option or set the PYTHONWARNDEFAULTENCODING environment variable, which will emit an EncodingWarning when the default encoding is used.

If you are providing an API that uses open() or TextIOWrapper and passes encoding=None as a parameter, you can use text_encoding() so that callers of the API will emit an EncodingWarning if they don’t pass an encoding. However, please consider using UTF-8 by default (i.e. encoding="utf-8") for new APIs.

고수준 모듈 인터페이스

io.DEFAULT_BUFFER_SIZE

모듈의 버퍼링 된 I/O 클래스에서 사용하는 기본 버퍼 크기를 포함하는 int. open()은 가능하면 파일의 blksize(os.stat()으로 얻은)를 사용합니다.

io.open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)

이것은 내장 open() 함수의 별칭입니다.

This function raises an auditing event open with arguments path, mode and flags. The mode and flags arguments may have been modified or inferred from the original call.

io.open_code(path)

제공된 파일을 'rb' 모드로 엽니다. 이 함수는 내용을 실행 코드로 취급하려고 할 때 사용해야 합니다.

path should be a str and an absolute path.

The behavior of this function may be overridden by an earlier call to the PyFile_SetOpenCodeHook(). However, assuming that path is a str and an absolute path, open_code(path) should always behave the same as open(path, 'rb'). Overriding the behavior is intended for additional validation or preprocessing of the file.

Added in version 3.8.

io.text_encoding(encoding, stacklevel=2, /)

This is a helper function for callables that use open() or TextIOWrapper and have an encoding=None parameter.

This function returns encoding if it is not None. Otherwise, it returns "locale" or "utf-8" depending on UTF-8 Mode.

This function emits an EncodingWarning if sys.flags.warn_default_encoding is true and encoding is None. stacklevel specifies where the warning is emitted. For example:

def read_text(path, encoding=None):
    encoding = io.text_encoding(encoding)  # stacklevel=2
    with open(path, encoding) as f:
        return f.read()

In this example, an EncodingWarning is emitted for the caller of read_text().

See Text Encoding for more information.

Added in version 3.10.

버전 3.11에서 변경: text_encoding() returns “utf-8” when UTF-8 mode is enabled and encoding is None.

exception io.BlockingIOError

이것은 내장 BlockingIOError 예외에 대한 호환 별칭입니다.

exception io.UnsupportedOperation

지원되지 않는 연산이 스트림에서 호출될 때 발생하는 OSError와 ValueError를 상속하는 예외.

더 보기

sys

표준 IO 스트림을 포함합니다: sys.stdin, sys.stdout 및 sys.stderr.

클래스 위계

I/O 스트림의 구현은 클래스의 위계(hierarchy)로 구성됩니다. 먼저 다양한 범주의 스트림을 지정하는 데 사용되는 추상 베이스 클래스(ABC)가 있고, 그다음으로 표준 스트림 구현을 제공하는 구상 클래스가 있습니다.

참고

The abstract base classes also provide default implementations of some methods in order to help implementation of concrete stream classes. For example, BufferedIOBase provides unoptimized implementations of readinto() and readline().

I/O 위계의 맨 위에는 추상 베이스 클래스 IOBase가 있습니다. 스트림에 대한 기본 인터페이스를 정의합니다. 그러나 스트림에 대한 읽기와 쓰기가 분리되지 않음에 유의하십시오; 구현은 주어진 연산을 지원하지 않으면 UnsupportedOperation을 발생시킬 수 있습니다.

RawIOBase ABC는 IOBase를 확장합니다. 스크림에 대한 바이트열의 읽기와 쓰기를 처리합니다. FileIO는 RawIOBase를 서브 클래싱하여 기계의 파일 시스템에 있는 파일에 대한 인터페이스를 제공합니다.

The BufferedIOBase ABC extends IOBase. It deals with buffering on a raw binary stream (RawIOBase). Its subclasses, BufferedWriter, BufferedReader, and BufferedRWPair buffer raw binary streams that are writable, readable, and both readable and writable, respectively. BufferedRandom provides a buffered interface to seekable streams. Another BufferedIOBase subclass, BytesIO, is a stream of in-memory bytes.

TextIOBase ABC는 IOBase를 확장합니다. 이것은 바이트가 텍스트를 나타내는 스트림을 다루고, 문자열과의 인코딩과 디코딩을 처리합니다. TextIOBase를 확장하는 TextIOWrapper는 버퍼링 된 원시 스트림(BufferedIOBase)에 대한 버퍼링 된 텍스트 인터페이스입니다. 마지막으로, StringIO는 텍스트에 대한 인 메모리 스트림입니다.

인자 이름은 명세의 일부가 아니며, open()의 인자는 키워드 인자로만 사용하려는 의도입니다.

다음 표는 io 모듈에서 제공하는 ABC를 요약합니다:

ABC

상속

스텁(stub) 메서드

믹스 인 메서드와 프로퍼티

IOBase

fileno, seek 및 truncate

close, closed, __enter__, __exit__, flush, isatty, __iter__, __next__, readable, readline, readlines, seekable, tell, writable 및 writelines

RawIOBase

IOBase

readinto와 write

상속된 IOBase 메서드, read 및 readall

BufferedIOBase

IOBase

detach, read, read1 및 write

상속된 IOBase 메서드, readinto 및 readinto1

TextIOBase

IOBase

detach, read, readline 및 write

상속된 IOBase 메서드, encoding, errors 및 newlines

I/O 베이스 클래스

class io.IOBase

The abstract base class for all I/O classes.

이 클래스는 파생 클래스가 선택적으로 재정의할 수 있는 많은 메서드에 대해 빈 추상 구현을 제공합니다; 기본 구현은 읽거나 쓰거나 탐색할 수 없는 파일을 나타냅니다.

Even though IOBase does not declare read() or write() because their signatures will vary, implementations and clients should consider those methods part of the interface. Also, implementations may raise a ValueError (or UnsupportedOperation) when operations they do not support are called.

파일에서 읽거나 파일에 쓰는 바이너리 데이터에 사용되는 기본형은 bytes입니다. 다른 바이트열류 객체도 메서드 인자로 허용됩니다. 텍스트 I/O 클래스는 str 데이터로 작동합니다.

닫힌 스트림에 대한 모든 메서드(조회조차도) 호출은 정의되어 있지 않습니다. 이 경우 구현은 ValueError를 발생시킬 수 있습니다.

IOBase(및 그 서브 클래스)는 이터레이터 프로토콜을 지원합니다. 즉, 스트림에서 줄을 산출하면서 IOBase 객체를 이터레이트 할 수 있습니다. 스트림이 바이너리 스트림(바이트열을 산출합니다)인지 텍스트 스트림(문자열을 산출합니다)인지에 따라 줄은 약간 다르게 정의됩니다. 아래 readline()을 참조하십시오.

IOBase는 컨텍스트 관리자이기도 해서, with 문을 지원합니다. 이 예에서, file은 with 문의 스위트가 완료된 후에 닫힙니다 — 예외가 발생하더라도:

with open('spam.txt', 'w') as file:
    file.write('Spam and eggs!')

IOBase는 다음 데이터 어트리뷰트와 메서드를 제공합니다:

close()

이 스트림을 플러시하고 닫습니다. 파일이 이미 닫혔으면 이 메서드는 효과가 없습니다. 일단 파일이 닫히면, 파일에 대한 모든 연산(예를 들어 읽기나 쓰기)이 ValueError를 발생시킵니다.

편의상, 이 메서드를 두 번 이상 호출할 수 있습니다; 그러나 첫 번째 호출만 효과가 있습니다.

closed

스트림이 닫혔으면 True.

fileno()

존재한다면 스트림의 하부 파일 기술자(정수)를 반환합니다. IO 객체가 파일 기술자를 사용하지 않으면 OSError가 발생합니다.

flush()

해당하면 스트림의 쓰기 버퍼를 플러시합니다. 이것은 읽기 전용과 비 블로킹 스트림에 대해서는 아무것도 하지 않습니다.

isatty()

스트림이 대화형이면 (즉, 터미널/tty 장치에 연결되었으면) True를 반환합니다.

readable()

Return True if the stream can be read from. If False, read() will raise OSError.

readline(size=-1, /)

스트림에서 한 줄을 읽고 반환합니다. size가 지정되면, 최대 size 바이트를 읽습니다.

줄 종결자는 바이너리 파일의 경우 항상 b'\n'입니다; 텍스트 파일의 경우, open()에 대한 newline 인자를 사용하여 인식되는 줄 종결자를 선택할 수 있습니다.

readlines(hint=-1, /)

스트림에서 줄 리스트를 읽고 반환합니다. hint는 읽을 줄 수를 제어하도록 지정할 수 있습니다: 지금까지 모든 줄의 총 크기(바이트/문자 단위)가 hint를 초과하면 더는 줄을 읽지 않습니다.

hint values of 0 or less, as well as None, are treated as no hint.

Note that it’s already possible to iterate on file objects using for line in file: ... without calling file.readlines().

seek(offset, whence=os.SEEK_SET, /)

Change the stream position to the given byte offset, interpreted relative to the position indicated by whence, and return the new absolute position. Values for whence are:

os.SEEK_SET or 0 – start of the stream (the default); offset should be zero or positive

os.SEEK_CUR or 1 – current stream position; offset may be negative

os.SEEK_END or 2 – end of the stream; offset is usually negative

Added in version 3.1: The SEEK_* constants.

Added in version 3.3: Some operating systems could support additional values, like os.SEEK_HOLE or os.SEEK_DATA. The valid values for a file could depend on it being open in text or binary mode.

seekable()

스트림이 무작위 액세스를 지원하면 True를 반환합니다. False이면, seek(), tell() 및 truncate()가 OSError를 발생시킵니다.

tell()

현재의 스트림 위치를 반환합니다.

truncate(size=None, /)

바이트 단위로 지정된 size로 스트림 크기를 조정합니다 (또는 size가 지정되지 않으면 현재 위치). 현재 스트림 위치는 변경되지 않습니다. 이 크기 조정은 현재 파일 크기를 늘리거나 줄일 수 있습니다. 확장의 경우, 새 파일 영역의 내용은 플랫폼에 따라 다릅니다 (대부분의 시스템에서, 추가 바이트는 0으로 채워집니다). 새 파일 크기가 반환됩니다.

버전 3.5에서 변경: 윈도우는 이제 확장 시 파일을 0으로 채웁니다.

writable()

Return True if the stream supports writing. If False, write() and truncate() will raise OSError.

writelines(lines, /)

스트림에 줄 리스트를 씁니다. 줄 구분자는 추가되지 않아서, 제공된 각 줄 끝에 줄 구분자가 있는 것이 일반적입니다.

__del__()

객체 파괴를 준비합니다. IOBase는 인스턴스의 close() 메서드를 호출하는 이 메서드의 기본 구현을 제공합니다.

class io.RawIOBase

Base class for raw binary streams. It inherits from IOBase.

원시 바이너리 스트림은 일반적으로 하부 OS 장치나 API에 대한 저수준 액세스를 제공하며, 이것을 고수준 프리미티브로 캡슐화하려고 하지 않습니다 (이 기능은 이 페이지에서 나중에 설명할 버퍼링 된 바이너리 스트림과 텍스트 스트림에서 고수준으로 수행됩니다).

RawIOBase는 IOBase에서 온 것 외에 이 메서드를 제공합니다:

read(size=-1, /)

객체에서 최대 size 바이트를 읽고 반환합니다. 편의상, size가 지정되지 않거나 -1이면, EOF까지의 모든 바이트가 반환됩니다. 그렇지 않으면, 하나의 시스템 호출만 수행됩니다. 운영 체제 시스템 호출이 size 바이트 미만을 반환하면 size 바이트 미만이 반환될 수 있습니다.

0바이트가 반환되고, size가 0이 아니면, 파일의 끝을 나타냅니다. 객체가 비 블로킹 모드이고 사용 가능한 바이트가 없으면 None이 반환됩니다.

기본 구현은 readall()과 readinto()로 위임합니다.

readall()

필요한 경우 스트림에 대한 다중 호출을 사용하여, EOF까지 스트림의 모든 바이트를 읽고 반환합니다.

readinto(b, /)

미리 할당되고, 쓰기 가능한 바이트열류 객체 b로 바이트를 읽고 읽은 바이트 수를 반환합니다. 예를 들어, b는 bytearray일 수 있습니다. 객체가 비 블로킹 모드이고 사용 가능한 바이트가 없으면, None이 반환됩니다.

write(b, /)

주어진 바이트열류 객체, b를 하부 원시 스트림에 쓰고, 쓴 바이트 수를 반환합니다. 하부 원시 스트림의 특성에 따라, 특히 비 블로킹 모드이면 바이트 단위로 b의 길이보다 짧을 수 있습니다. 원시 스트림이 블록 하지 않도록 설정되었고 단일 바이트를 당장 쓸 수 없으면 None이 반환됩니다. 호출자는 이 메서드가 반환된 후 b를 해제하거나 변경할 수 있어서, 구현은 메서드 호출 중에만 b에 액세스해야 합니다.

class io.BufferedIOBase

Base class for binary streams that support some kind of buffering. It inherits from IOBase.

RawIOBase와의 주요 차이점은 메서드 read(), readinto() 및 write()는 요청된 만큼 많은 입력을 읽거나 주어진 출력을 모두 소비하려고 시도한다는 것입니다, 아마도 하나 이상의 시스템 호출을 하는 비용을 치르고서라도.

또한, 하부 원시 스트림이 비 블로킹 모드에 있고 충분한 데이터를 취하거나 제공할 수 없으면 이러한 메서드들은 BlockingIOError를 발생시킬 수 있습니다; RawIOBase의 메서드들과는 달리 None을 반환하지 않습니다.

또한, read() 메서드에는 readinto()로 위임하는 기본 구현이 없습니다.

일반적인 BufferedIOBase 구현은 RawIOBase 구현에서 상속하지 말고, BufferedWriter와 BufferedReader처럼 감싸야 합니다.

BufferedIOBase는 IOBase에서 온 것 외에 다음 데이터 어트리뷰트와 메서드를 제공하거나 재정의합니다:

raw

BufferedIOBase 가 다루는 하부 원시 스트림 (RawIOBase 인스턴스). 이것은 BufferedIOBase API의 일부가 아니며 일부 구현에는 없을 수 있습니다.

detach()

하부 원시 스트림을 버퍼에서 분리하고 반환합니다.

원시 스트림이 분리된 후에는, 버퍼가 사용할 수 없는 상태가 됩니다.

BytesIO와 같은 일부 버퍼에는 이 메서드가 반환할 단일 원시 스트림 개념이 없습니다. 그들은 UnsupportedOperation을 발생시킵니다.

Added in version 3.1.

read(size=-1, /)

최대 size 바이트를 읽고 반환합니다. 인자가 생략되거나, None이거나 음수이면, EOF에 도달할 때까지 데이터를 읽고 반환합니다. 스트림이 이미 EOF에 있으면 빈 bytes 객체가 반환됩니다.

인자가 양수이고, 하부 원시 스트림이 대화식이 아니면, 바이트 수를 충족시키기 위해 여러 원시 읽기가 수행될 수 있습니다 (EOF에 먼저 도달하지 않는 한). 그러나 대화식 원시 스트림의 경우, 최대 하나의 원시 읽기가 수행되고 짧은 결과가 EOF가 임박했음을 의미하지는 않습니다.

하부 원시 스트림이 비 블로킹 모드이고, 현재 사용 가능한 데이터가 없으면 BlockingIOError 가 발생합니다.

read1(size=-1, /)

하부 원시 스트림의 read() (또는 readinto()) 메서드를 최대 한 번만 호출하여, 최대 size 바이트를 읽고 반환합니다. BufferedIOBase 객체 위에 자체 버퍼링을 구현하는 경우 유용할 수 있습니다.

size가 -1(기본값)이면, 임의의 수의 바이트가 반환됩니다 (EOF에 도달하지 않았으면 0보다 큽니다).

readinto(b, /)

미리 할당되고, 쓰기 가능한 바이트열류 객체 b로 바이트를 읽고 읽은 바이트 수를 반환합니다. 예를 들어, b는 bytearray일 수 있습니다.

read()와 마찬가지로, 하부 원시 스트림이 대화식이 아닌 한, 여러 읽기가 수행될 수 있습니다.

하부 원시 스트림이 비 블로킹 모드이고, 현재 사용 가능한 데이터가 없으면 BlockingIOError 가 발생합니다.

readinto1(b, /)

하부 원시 스트림의 read() (또는 readinto()) 메서드를 최대 한 번만 호출하여, 미리 할당된 쓰기 가능한 바이트열류 객체 b로 바이트를 읽습니다. 읽은 바이트 수를 반환합니다.

하부 원시 스트림이 비 블로킹 모드이고, 현재 사용 가능한 데이터가 없으면 BlockingIOError 가 발생합니다.

Added in version 3.5.

write(b, /)

주어진 바이트열류 객체, b를 쓰고 기록된 바이트 수를 반환합니다 (쓰기에 실패하면 OSError가 발생하기 때문에 항상 바이트 단위로 b 길이와 같습니다). 실제 구현에 따라, 이러한 바이트는 하부 스트림에 쉽게 쓸 수 있거나, 성능과 지연 이유로 버퍼에 보관될 수 있습니다.

비 블로킹 모드에서, 데이터를 원시 스트림에 기록해야 하지만 원시 스트림이 블로킹 없이 모든 데이터를 받아들일 수 없으면, BlockingIOError 가 발생합니다.

호출자는 이 메서드가 반환된 후 b를 해제하거나 변경할 수 있어서, 구현은 메서드 호출 중에만 b에 액세스해야 합니다.

원시 파일 I/O

class io.FileIO(name, mode='r', closefd=True, opener=None)

A raw binary stream representing an OS-level file containing bytes data. It inherits from RawIOBase.

name은 다음 두 가지 중 하나일 수 있습니다:

열릴 파일의 경로를 나타내는 문자열이나 bytes 객체. 이 경우 closefd는 True(기본값)이어야 합니다. 그렇지 않으면 에러가 발생합니다.

결과 FileIO 객체가 액세스할 기존 OS 수준 파일 기술자의 번호를 나타내는 정수. FileIO 객체가 닫힐 때, closefd가 False로 설정되어 있지 않은 한 이 fd도 닫힙니다.

mode는 읽기(기본값), 쓰기, 배타적 생성 또는 덧붙이기를 위해 'r', 'w', 'x' 또는 'a'일 수 있습니다. 쓰기나 덧붙이기로 열 때 파일이 존재하지 않으면 만들어집니다; 쓰기 위해 열면 파일이 잘립니다. 생성을 위해 열었을 때 파일이 이미 존재하면 FileExistsError 가 발생합니다. 생성하기 위해 파일을 여는 것은 쓰기를 의미하므로, 이 모드는 'w'와 유사한 방식으로 작동합니다. 읽기와 쓰기를 동시에 허락하려면 '+'를 모드에 추가하십시오.

The read() (when called with a positive argument), readinto() and write() methods on this class will only make one system call.

콜러블을 opener로 전달하여 사용자 정의 오프너를 사용할 수 있습니다. 그러면 파일 객체의 하부 파일 기술자는 (name, flags)로 opener를 호출하여 얻습니다. opener는 열린 파일 기술자를 반환해야 합니다 (os.open을 opener로 전달하면 None을 전달하는 것과 유사한 기능이 됩니다).

새로 만들어진 파일은 상속 불가능합니다.

opener 매개 변수 사용에 대한 예는 open() 내장 함수를 참조하십시오.

버전 3.3에서 변경: opener 매개 변수가 추가되었습니다. 'x' 모드가 추가되었습니다.

버전 3.4에서 변경: 이제 파일이 상속 불가능합니다.

FileIO는 RawIOBase와 IOBase에서 온 것 외에 다음 데이터 어트리뷰트를 제공합니다:

mode

생성자에 제공된 모드.

name

파일 이름. 생성자에 이름이 지정되지 않으면 파일의 파일 기술자입니다.

버퍼링 된 스트림

버퍼링 된 I/O 스트림은 원시 I/O보다 I/O 장치에 대한 더 고수준의 인터페이스를 제공합니다.

class io.BytesIO(initial_bytes=b'')

A binary stream using an in-memory bytes buffer. It inherits from BufferedIOBase. The buffer is discarded when the close() method is called.

선택적 인자 initial_bytes는 초기 데이터를 포함하는 바이트열류 객체입니다.

BytesIO는 BufferedIOBase와 IOBase의 메서드 외에 다음 메서드를 제공하거나 재정의합니다:

getbuffer()

복사하지 않고 버퍼의 내용에 대한 읽을 수 있고 쓸 수 있는 뷰를 반환합니다. 또한, 뷰를 변경하면 버퍼의 내용이 투명하게 갱신됩니다:

>>> b = io.BytesIO(b"abcdef")
>>> view = b.getbuffer()
>>> view[2:4] = b"56"
>>> b.getvalue()
b'ab56ef'

참고

뷰가 존재하는 한, BytesIO 객체의 크기를 조정하거나 닫을 수 없습니다.

Added in version 3.2.

getvalue()

버퍼의 전체 내용을 포함하는 bytes를 반환합니다.

read1(size=-1, /)

BytesIO에서, 이것은 read()와 같습니다.

버전 3.7에서 변경: size 인자는 이제 선택적입니다.

readinto1(b, /)

BytesIO에서, 이것은 readinto()와 같습니다.

Added in version 3.5.

class io.BufferedReader(raw, buffer_size=DEFAULT_BUFFER_SIZE)

A buffered binary stream providing higher-level access to a readable, non seekable RawIOBase raw binary stream. It inherits from BufferedIOBase.

이 객체에서 데이터를 읽을 때, 하부 원시 스트림에서 더 많은 양의 데이터가 요청되어, 내부 버퍼에 보관될 수 있습니다. 버퍼링 된 데이터는 후속 읽기에서 직접 반환될 수 있습니다.

생성자는 주어진 읽을 수 있는 raw 스트림과 buffer_size에 대해 BufferedReader를 만듭니다. buffer_size를 생략하면, DEFAULT_BUFFER_SIZE가 사용됩니다.

BufferedReader는 BufferedIOBase와 IOBase의 메서드 외에 다음 메서드를 제공하거나 재정의합니다:

peek(size=0, /)

위치를 전진시키지 않고 스트림에서 바이트열을 반환합니다. 호출을 충족시키기 위해 원시 스트림에서 최대 하나의 단일 읽기가 수행됩니다. 반환된 바이트 수는 요청된 것보다 적거나 많을 수 있습니다.

read(size=-1, /)

size 바이트를, size가 주어지지 않았거나 음수이면, EOF까지 혹은 읽기 호출이 비 블로킹 모드에서 블록 되기 전까지 읽고 반환합니다.

read1(size=-1, /)

원시 스트림에 대한 한 번의 호출로 최대 size 바이트를 읽고 반환합니다. 적어도 1바이트가 버퍼링 되어 있으면, 버퍼링 된 바이트만 반환됩니다. 그렇지 않으면, 하나의 원시 스트림 읽기 호출이 수행됩니다.

버전 3.7에서 변경: size 인자는 이제 선택적입니다.

class io.BufferedWriter(raw, buffer_size=DEFAULT_BUFFER_SIZE)

A buffered binary stream providing higher-level access to a writeable, non seekable RawIOBase raw binary stream. It inherits from BufferedIOBase.

이 객체에 쓸 때, 데이터는 일반적으로 내부 버퍼에 배치됩니다. 버퍼는 다음과 같은 다양한 조건에서 하부 RawIOBase 객체에 기록됩니다:

계류 중인 모든 데이터에 비해 버퍼가 너무 작아질 때;

when flush() is called;

when a seek() is requested (for BufferedRandom objects);

BufferedWriter 객체가 닫히거나 파괴될 때.

생성자는 주어진 쓰기 가능한 raw 스트림에 대해 BufferedWriter를 만듭니다. buffer_size가 제공되지 않으면, 기본값은 DEFAULT_BUFFER_SIZE입니다.

BufferedWriter는 BufferedIOBase와 IOBase의 메서드 외에 다음 메서드를 제공하거나 재정의합니다:

flush()

버퍼에 있는 바이트를 원시 스트림으로 강제 출력합니다. 원시 스트림이 블록되면 BlockingIOError를 발생시켜야 합니다.

write(b, /)

바이트열류 객체, b를 쓰고 쓴 바이트 수를 반환합니다. 비 블로킹 모드일 때, 버퍼를 기록해야 하지만 원시 스트림이 블록하면 BlockingIOError 가 발생합니다.

class io.BufferedRandom(raw, buffer_size=DEFAULT_BUFFER_SIZE)

A buffered binary stream providing higher-level access to a seekable RawIOBase raw binary stream. It inherits from BufferedReader and BufferedWriter.

생성자는 첫 번째 인자로 주어진 탐색 가능한 원시 스트림에 대한 판독기(reader)와 기록기(writer)를 만듭니다. buffer_size를 생략하면 기본값은 DEFAULT_BUFFER_SIZE입니다.

BufferedRandom is capable of anything BufferedReader or BufferedWriter can do. In addition, seek() and tell() are guaranteed to be implemented.

class io.BufferedRWPair(reader, writer, buffer_size=DEFAULT_BUFFER_SIZE, /)

A buffered binary stream providing higher-level access to two non seekable RawIOBase raw binary streams—one readable, the other writeable. It inherits from BufferedIOBase.

reader와 writer는 각각 읽고 쓸 수 있는 RawIOBase 객체입니다. buffer_size가 생략되면 기본값은 DEFAULT_BUFFER_SIZE입니다.

BufferedRWPair는 UnsupportedOperation을 발생시키는 detach()를 제외한 모든 BufferedIOBase 의 메서드를 구현합니다.

경고

BufferedRWPair는 하부 원시 스트림에 대한 동기화된 액세스를 시도하지 않습니다. reader와 writer로 같은 객체를 전달해서는 안 됩니다; 대신 BufferedRandom을 사용하십시오.

텍스트 I/O

class io.TextIOBase

Base class for text streams. This class provides a character and line based interface to stream I/O. It inherits from IOBase.

TextIOBase는 IOBase에서 온 것 외에 다음 데이터 어트리뷰트와 메서드를 제공하거나 재정의합니다:

encoding

스트림의 바이트열을 문자열로 디코딩하고, 문자열을 바이트열로 인코딩하는 데 사용되는 인코딩의 이름.

errors

디코더나 인코더의 에러 설정.

newlines

지금까지 번역된 줄 넘김을 나타내는, 문자열, 문자열 튜플 또는 None. 구현과 초기 생성자 플래그에 따라, 사용하지 못할 수 있습니다.

buffer

TextIOBase가 다루는 하부 바이너리 버퍼 (BufferedIOBase 인스턴스). 이것은 TextIOBase API의 일부가 아니며 일부 구현에는 없을 수 있습니다.

detach()

하부 바이너리 버퍼를 TextIOBase와 분리하여 반환합니다.

하부 버퍼가 분리된 후에는, TextIOBase는 사용할 수 없는 상태가 됩니다.

StringIO와 같은 일부 TextIOBase 구현에는 하부 버퍼 개념이 없을 수 있으며 이 메서드를 호출하면 UnsupportedOperation이 발생합니다.

Added in version 3.1.

read(size=-1, /)

스트림에서 최대 size 문자를 단일 str로 읽고 반환합니다. size가 음수이거나 None이면 EOF까지 읽습니다.

readline(size=-1, /)

Read until newline or EOF and return a single str. If the stream is already at EOF, an empty string is returned.

size가 지정되면, 최대 size 문자를 읽습니다.

seek(offset, whence=SEEK_SET, /)

Change the stream position to the given offset. Behaviour depends on the whence parameter. The default value for whence is SEEK_SET.

SEEK_SET or 0: seek from the start of the stream (the default); offset must either be a number returned by TextIOBase.tell(), or zero. Any other offset value produces undefined behaviour.

SEEK_CUR or 1: “seek” to the current position; offset must be zero, which is a no-operation (all other values are unsupported).

SEEK_END or 2: seek to the end of the stream; offset must be zero (all other values are unsupported).

새로운 절대 위치를 불투명한 숫자로 반환합니다.

Added in version 3.1: The SEEK_* constants.

tell()

현재 스트림 위치를 불투명한 숫자로 반환합니다. 숫자는 일반적으로 하부 바이너리 저장소의 바이트 수를 나타내지 않습니다.

write(s, /)

문자열 s를 스트림에 쓰고 쓴 문자 수를 반환합니다.

class io.TextIOWrapper(buffer, encoding=None, errors=None, newline=None, line_buffering=False, write_through=False)

A buffered text stream providing higher-level access to a BufferedIOBase buffered binary stream. It inherits from TextIOBase.

encoding gives the name of the encoding that the stream will be decoded or encoded with. It defaults to locale.getencoding(). encoding="locale" can be used to specify the current locale’s encoding explicitly. See Text Encoding for more information.

errors는 인코딩과 디코딩 에러 처리 방법을 지정하는 선택적 문자열입니다. 인코딩 에러가 있을 때 ValueError 예외를 발생시키려면 'strict'를 전달하고 (기본값 None은 같은 효과를 줍니다), 에러를 무시하려면 'ignore'를 전달하십시오. (인코딩 에러를 무시하면 데이터가 손실될 수 있음에 유의하십시오.) 'replace'는 잘못된 데이터가 있는 곳에 대체 마커(가령 '?')가 삽입되도록 합니다. 'backslashreplace'는 잘못된 데이터를 역 슬래시 이스케이프 시퀀스로 대체합니다. 기록할 때, 'xmlcharrefreplace'(적절한 XML 문자 참조로 대체합니다)나 'namereplace'(\N{...} 이스케이프 시퀀스로 대체합니다)를 사용할 수 있습니다. codecs.register_error()로 등록된 다른 에러 처리 이름도 유효합니다.

newline은 줄 끝 처리 방법을 제어합니다. None, '', '\n', '\r' 및 '\r\n' 일 수 있습니다. 다음과 같이 작동합니다:

스트림에서 입력을 읽을 때, newline이 None이면, 유니버설 줄 넘김 모드가 활성화됩니다. 입력의 줄은 '\n', '\r' 또는 '\r\n'으로 끝날 수 있으며, 호출자에게 반환되기 전에 '\n'으로 변환됩니다. newline이 ''이면, 유니버설 줄 넘김 모드가 활성화되지만, 줄 끝은 변환되지 않은 상태로 호출자에게 반환됩니다. newline이 다른 유효한 값이면, 입력 줄은 주어진 문자열로만 끝나고, 줄 끝은 변환되지 않은 상태로 호출자에게 반환됩니다.

스트림에 출력을 기록할 때, newline이 None이면, 기록되는 모든 '\n' 문자는 시스템 기본 줄 구분자 os.linesep으로 변환됩니다. newline이 ''이나 '\n'이면, 변환이 수행되지 않습니다. newline이 다른 유효한 값이면, 기록되는 모든 '\n' 문자는 주어진 문자열로 변환됩니다.

If line_buffering is True, flush() is implied when a call to write contains a newline character or a carriage return.

If write_through is True, calls to write() are guaranteed not to be buffered: any data written on the TextIOWrapper object is immediately handled to its underlying binary buffer.

버전 3.3에서 변경: write_through 인자가 추가되었습니다.

버전 3.3에서 변경: 기본 encoding은 이제 locale.getpreferredencoding() 대신 locale.getpreferredencoding(False)입니다. locale.setlocale()을 사용하여 임시 로케일 인코딩을 변경하지 않고, 사용자가 선호하는 인코딩 대신 현재 로케일 인코딩을 사용합니다.

버전 3.10에서 변경: The encoding argument now supports the "locale" dummy encoding name.

TextIOWrapper는 TextIOBase와 IOBase에서 온 것 외에 다음 데이터 어트리뷰트와 메서드를 제공합니다:

line_buffering

줄 버퍼링이 활성화되었는지 여부.

write_through

쓰기가 하부 바이너리 버퍼로 즉시 전달되는지 여부.

Added in version 3.7.

reconfigure(*, encoding=None, errors=None, newline=None, line_buffering=None, write_through=None)

encoding, errors, newline, line_buffering 및 write_through에 대한 새로운 설정을 사용하여 이 텍스트 스트림을 재구성합니다.

encoding이 지정되었지만, errors가 지정되지 않았을 때 errors='strict'가 사용되는 것을 제외하고, 지정되지 않은 매개 변수는 현재 설정을 유지합니다.

스트림에서 일부 데이터를 이미 읽었다면 encoding이나 newline을 변경할 수 없습니다. 반면에, 기록 후의 encoding 변경은 가능합니다.

이 메서드는 새 매개 변수를 설정하기 전에 묵시적 스트림 플러시를 수행합니다.

Added in version 3.7.

버전 3.11에서 변경: The method supports encoding="locale" option.

seek(cookie, whence=os.SEEK_SET, /)

Set the stream position. Return the new stream position as an int.

Four operations are supported, given by the following argument combinations:

seek(0, SEEK_SET): Rewind to the start of the stream.

seek(cookie, SEEK_SET): Restore a previous position; cookie must be a number returned by tell().

seek(0, SEEK_END): Fast-forward to the end of the stream.

seek(0, SEEK_CUR): Leave the current stream position unchanged.

Any other argument combinations are invalid, and may raise exceptions.

더 보기

os.SEEK_SET, os.SEEK_CUR, and os.SEEK_END.

tell()

Return the stream position as an opaque number. The return value of tell() can be given as input to seek(), to restore a previous stream position.

class io.StringIO(initial_value='', newline='\n')

A text stream using an in-memory text buffer. It inherits from TextIOBase.

close() 메서드가 호출될 때 텍스트 버퍼가 폐기됩니다.

The initial value of the buffer can be set by providing initial_value. If newline translation is enabled, newlines will be encoded as if by write(). The stream is positioned at the start of the buffer which emulates opening an existing file in a w+ mode, making it ready for an immediate write from the beginning or for a write that would overwrite the initial value. To emulate opening a file in an a+ mode ready for appending, use f.seek(0, io.SEEK_END) to reposition the stream at the end of the buffer.

출력을 스트림에 쓸 때, newline이 None이면, 모든 플랫폼에서 줄 넘김이 \n로 기록된다는 점을 제외하고는, newline 인자는 TextIOWrapper에서 처럼 작동합니다.

StringIO는 TextIOBase와 IOBase의 메서드 외에 이 메서드를 제공합니다:

getvalue()

Return a str containing the entire contents of the buffer. Newlines are decoded as if by read(), although the stream position is not changed.

사용 예:

import io

output = io.StringIO()
output.write('First line.\n')
print('Second line.', file=output)

# Retrieve file contents -- this will be
# 'First line.\nSecond line.\n'
contents = output.getvalue()

# Close object and discard memory buffer --
# .getvalue() will now raise an exception.
output.close()

class io.IncrementalNewlineDecoder

A helper codec that decodes newlines for universal newlines mode. It inherits from codecs.IncrementalDecoder.

성능

이 섹션에서는 제공된 구상 I/O 구현의 성능에 대해 논합니다.

바이너리 I/O

사용자가 단일 바이트를 요청할 때조차 큰 데이터 청크만 읽고 써서, 버퍼링 된 I/O는 운영 체제의 버퍼링 되지 않은 I/O 루틴을 호출하고 실행할 때의 비효율성을 숨깁니다. 이득은 OS 와 수행되는 I/O 종류에 따라 다릅니다. 예를 들어, 리눅스와 같은 일부 최신 OS에서는, 버퍼링 되지 않은 디스크 I/O는 버퍼링 된 I/O만큼 빠를 수 있습니다. 그러나 요점은 버퍼링 된 I/O가 플랫폼과 배경 장치와 관계없이 예측 가능한 성능을 제공한다는 것입니다. 따라서, 바이너리 데이터에는 버퍼링 되지 않은 I/O보다는 버퍼링 된 I/O를 사용하는 것이 거의 항상 바람직합니다.

텍스트 I/O

Text I/O over a binary storage (such as a file) is significantly slower than binary I/O over the same storage, because it requires conversions between unicode and binary data using a character codec. This can become noticeable handling huge amounts of text data like large log files. Also, tell() and seek() are both quite slow due to the reconstruction algorithm used.

그러나, StringIO는 네이티브 인 메모리 유니코드 컨테이너이며 BytesIO와 비슷한 속도를 나타냅니다.

다중 스레드

FileIO objects are thread-safe to the extent that the operating system calls (such as read(2) [https://manpages.debian.org/read(2)] under Unix) they wrap are thread-safe too.

바이너리 버퍼링 된 객체(BufferedReader, BufferedWriter, BufferedRandom 및 BufferedRWPair 의 인스턴스)는 록을 사용하여 내부 구조를 보호합니다; 따라서 여러 스레드에서 동시에 호출하는 것이 안전합니다.

TextIOWrapper 객체는 스레드 안전하지 않습니다.

재진입

바이너리 버퍼링 된 객체(BufferedReader, BufferedWriter, BufferedRandom 및 BufferedRWPair 의 인스턴스)는 재진입할 수 없습니다. 재진입 호출이 정상적인 상황에서는 발생하지 않지만, signal 처리기에서 I/O를 수행한다면 발생할 수 있습니다. 스레드가 이미 액세스 중인 버퍼링 된 객체에 다시 진입하려고 하면, RuntimeError가 발생합니다. 이것이 다른 스레드가 버퍼링 된 객체에 진입하는 것을 막는 것은 아님에 유의하십시오.

The above implicitly extends to text files, since the open() function will wrap a buffered object inside a TextIOWrapper. This includes standard streams and therefore affects the built-in print() function as well.

time — Time access and conversions

이 모듈은 다양한 시간 관련 함수를 제공합니다. 관련 기능에 대해서는, datetime과 calendar 모듈도 참조하십시오.

이 모듈을 항상 사용할 수 있지만, 모든 플랫폼에서 모든 함수를 사용할 수 있는 것은 아닙니다. 이 모듈에 정의된 대부분의 함수는 같은 이름의 플랫폼 C 라이브러리 함수를 호출합니다. 이러한 함수의 의미는 플랫폼마다 달라서, 플랫폼 설명서를 참조하면 도움이 될 수 있습니다.

일부 용어와 관례에 대한 설명을 순서대로 제시합니다.

The epoch is the point where the time starts, the return value of time.gmtime(0). It is January 1, 1970, 00:00:00 (UTC) on all platforms.

용어 에포크 이후의 초(seconds since the epoch)는 에포크 이후로 총 지나간 초를 나타내는데, 보통 윤초 [https://en.wikipedia.org/wiki/Leap_second]는 제외합니다. 모든 POSIX 호환 플랫폼에서 윤초는 이 총계에서 제외됩니다.

The functions in this module may not handle dates and times before the epoch or far in the future. The cut-off point in the future is determined by the C library; for 32-bit systems, it is typically in 2038.

함수 strptime()은 %y 포맷 코드가 제공될 때 2자리 연도를 구문 분석할 수 있습니다. 2자리 연도를 구문 분석할 때, POSIX와 ISO C 표준에 따라 변환됩니다: 값 69–99는 1969–1999에, 값 0–68은 2000–2068에 매핑됩니다.

UTC는 협정 세계시(Coordinated Universal Time) – 예전에는 그리니치 표준시(Greenwich Mean Time) 또는 GMT로 알려졌습니다. 약어 UTC는 실수가 아니라 영어와 프랑스어 간의 절충입니다.

DST는 일광 절약 시간(Daylight Saving Time)인데, 일 년 중 일부 기간 시간대를 (일반적으로) 한 시간 조정합니다. DST 규칙은 매직(현지 법에 따라 결정됩니다)이며 해가 바뀜에 따라 변경될 수 있습니다. C 라이브러리에는 현지 규칙이 포함된 테이블이 있으며 (종종 유연성을 위해 시스템 파일에서 읽습니다) 이 점에서 진정한 지혜(True Wisdom)의 유일한 원천입니다.

다양한 실시간 함수의 정밀도는 값이나 인자가 표현되는 단위가 제안하는 것보다 못할 수 있습니다. 예를 들어 대부분의 유닉스 시스템에서 시계는 초당 50회나 100회만 “틱(ticks)”합니다.

On the other hand, the precision of time() and sleep() is better than their Unix equivalents: times are expressed as floating-point numbers, time() returns the most accurate time available (using Unix gettimeofday() where available), and sleep() will accept a time with a nonzero fraction (Unix select() is used to implement this, where available).

gmtime(), localtime() 및 strptime()에 의해 반환되고 asctime(), mktime() 및 strftime()이 받아들이는 시간 값은 9개의 정수의 시퀀스입니다. gmtime(), localtime() 및 strptime()의 반환 값은 개별 필드에 대한 어트리뷰트 이름도 제공합니다.

이러한 객체에 대한 설명은 struct_time을 참조하십시오.

버전 3.3에서 변경: The struct_time type was extended to provide the tm_gmtoff and tm_zone attributes when platform supports corresponding struct tm members.

버전 3.6에서 변경: The struct_time attributes tm_gmtoff and tm_zone are now available on all platforms.

시간 표현 간에 변환하려면 다음 함수를 사용하십시오:

변환 전

변환 후

변환 함수

에포크 이후 초

UTC의 struct_time

gmtime()

에포크 이후 초

현지 시간의 struct_time

localtime()

UTC의 struct_time

에포크 이후 초

calendar.timegm()

현지 시간의 struct_time

에포크 이후 초

mktime()

함수

time.asctime([t])

gmtime()이나 localtime() 이 반환한 시간을 나타내는 튜플이나 struct_time을 'Sun Jun 20 23:21:05 1993' 형식의 문자열로 변환합니다. 날짜(day) 필드는 두 문자 길이이며 날짜가 한자리이면 스페이스로 채워집니다, 예를 들어: 'Wed Jun  9 04:26:40 1993'.

t가 제공되지 않으면, localtime() 에서 반환된 현재 시각이 사용됩니다. 로케일 정보는 asctime()에서 사용되지 않습니다.

참고

같은 이름의 C 함수와 달리, asctime()은 끝에 줄 바꿈을 추가하지 않습니다.

time.pthread_getcpuclockid(thread_id)

지정된 thread_id에 대한 스레드 특정 CPU-시간 시계의 clk_id를 반환합니다.

thread_id에 적합한 값을 얻으려면 threading.get_ident() 나 threading.Thread 객체의 ident 어트리뷰트를 사용하십시오.

경고

유효하지 않거나 만료된 thread_id를 전달하면 정의되지 않은 동작이 발생할 수 있습니다, 가령 세그먼트 폴트(segmentation fault).

Availability: Unix

See the man page for pthread_getcpuclockid(3) [https://manpages.debian.org/pthread_getcpuclockid(3)] for further information.

Added in version 3.7.

time.clock_getres(clk_id)

지정된 시계 clk_id의 해상도(정밀도)를 반환합니다. clk_id에 허용되는 값 리스트는 시계 ID 상수를 참조하십시오.

Availability: Unix.

Added in version 3.3.

time.clock_gettime(clk_id) → float

지정된 시계 clk_id의 시간을 반환합니다. clk_id에 허용되는 값 리스트는 시계 ID 상수를 참조하십시오.

Use clock_gettime_ns() to avoid the precision loss caused by the float type.

Availability: Unix.

Added in version 3.3.

time.clock_gettime_ns(clk_id) → int

clock_gettime()과 비슷하지만, 시간을 나노초로 반환합니다.

Availability: Unix.

Added in version 3.7.

time.clock_settime(clk_id, time: float)

지정된 시계 clk_id의 시간을 설정합니다. 현재, CLOCK_REALTIME이 clk_id에 대해 유일하게 허용되는 값입니다.

Use clock_settime_ns() to avoid the precision loss caused by the float type.

Availability: Unix, not Android, not iOS.

Added in version 3.3.

time.clock_settime_ns(clk_id, time: int)

clock_settime()과 비슷하지만, 나노초로 시간을 설정합니다.

Availability: Unix, not Android, not iOS.

Added in version 3.7.

time.ctime([secs])

Convert a time expressed in seconds since the epoch to a string of a form: 'Sun Jun 20 23:21:05 1993' representing local time. The day field is two characters long and is space padded if the day is a single digit, e.g.: 'Wed Jun  9 04:26:40 1993'.

secs가 제공되지 않거나 None이면, time()이 반환하는 현재 시각이 사용됩니다. ctime(secs)는 asctime(localtime(secs))와 동등합니다. 로케일 정보는 ctime()에서 사용되지 않습니다.

time.get_clock_info(name)

지정된 시계에 대한 정보를 이름 공간 객체로 가져옵니다. 지원되는 시계 이름과 그 값을 읽는 해당 함수는 다음과 같습니다:

'monotonic': time.monotonic()

'perf_counter': time.perf_counter()

'process_time': time.process_time()

'thread_time': time.thread_time()

'time': time.time()

결과는 다음과 같은 어트리뷰트를 갖습니다:

adjustable: 시계가 자동으로 (예를 들어 NTP 데몬에 의해) 또는 시스템 관리자에 의해 수동으로 변경될 수 있으면 True, 그렇지 않으면 False

implementation: 시계값을 얻는 데 사용되는 하부 C 함수의 이름. 가능한 값은 시계 ID 상수를 참조하십시오.

monotonic: 시계가 뒤로 이동할 수 없으면 True, 그렇지 않으면 False

resolution: 초 단위의 시계 해상도 (float)

Added in version 3.3.

time.gmtime([secs])

Convert a time expressed in seconds since the epoch to a struct_time in UTC in which the dst flag is always zero. If secs is not provided or None, the current time as returned by time() is used. Fractions of a second are ignored. See above for a description of the struct_time object. See calendar.timegm() for the inverse of this function.

time.localtime([secs])

gmtime()과 같지만, 현지 시간으로 변환합니다. secs가 제공되지 않거나 None이면 time()에서 반환된 현재 시각이 사용됩니다. DST가 주어진 시간에 적용되면 dst 플래그는 1로 설정됩니다.

localtime() may raise OverflowError, if the timestamp is outside the range of values supported by the platform C localtime() or gmtime() functions, and OSError on localtime() or gmtime() failure. It’s common for this to be restricted to years between 1970 and 2038.

time.mktime(t)

This is the inverse function of localtime(). Its argument is the struct_time or full 9-tuple (since the dst flag is needed; use -1 as the dst flag if it is unknown) which expresses the time in local time, not UTC. It returns a floating-point number, for compatibility with time(). If the input value cannot be represented as a valid time, either OverflowError or ValueError will be raised (which depends on whether the invalid value is caught by Python or the underlying C libraries). The earliest date for which it can generate a time is platform-dependent.

time.monotonic() → float

단조(monotonic) 시계, 즉 뒤로 갈 수 없는 시계의 값을 (소수부가 있는 초로) 반환합니다. 시계는 시스템 시계 갱신의 영향을 받지 않습니다. 반환된 값의 기준점은 정의되어 있지 않아서, 두 호출 결과 간의 차이만 유효합니다.

Clock:

On Windows, call QueryPerformanceCounter() and QueryPerformanceFrequency().

On macOS, call mach_absolute_time() and mach_timebase_info().

On HP-UX, call gethrtime().

Call clock_gettime(CLOCK_HIGHRES) if available.

Otherwise, call clock_gettime(CLOCK_MONOTONIC).

Use monotonic_ns() to avoid the precision loss caused by the float type.

Added in version 3.3.

버전 3.5에서 변경: 이 함수는 이제 항상 사용 가능하며 항상 시스템 전체 수준입니다.

버전 3.10에서 변경: On macOS, the function is now system-wide.

time.monotonic_ns() → int

monotonic()과 비슷하지만, 시간을 나노초로 반환합니다.

Added in version 3.7.

time.perf_counter() → float

성능 카운터(performance counter), 즉 짧은 지속 시간을 측정하는 가장 높은 해상도를 가진 시계의 값을 (소수부가 있는 초로) 반환합니다. 수면 중 경과 시간이 포함되며 시스템 전체 수준입니다. 반환된 값의 기준점은 정의되어 있지 않아서, 두 호출 결과 간의 차이만 유효합니다.

CPython 구현 상세: On CPython, use the same clock as time.monotonic() and is a monotonic clock, i.e. a clock that cannot go backwards.

Use perf_counter_ns() to avoid the precision loss caused by the float type.

Added in version 3.3.

버전 3.10에서 변경: On Windows, the function is now system-wide.

버전 3.13에서 변경: Use the same clock as time.monotonic().

time.perf_counter_ns() → int

perf_counter()와 비슷하지만, 시간을 나노초로 반환합니다.

Added in version 3.7.

time.process_time() → float

현재 프로세스의 시스템과 사용자 CPU 시간 합계의 값을 (소수부가 있는 초로) 반환합니다. 수면 중 경과 시간은 포함되지 않습니다. 정의상 프로세스 수준입니다. 반환된 값의 기준점은 정의되어 있지 않아서, 두 호출 결과 간의 차이만 유효합니다.

Use process_time_ns() to avoid the precision loss caused by the float type.

Added in version 3.3.

time.process_time_ns() → int

process_time()과 비슷하지만, 시간을 나노초로 반환합니다.

Added in version 3.7.

time.sleep(secs)

Suspend execution of the calling thread for the given number of seconds. The argument may be a floating-point number to indicate a more precise sleep time.

If the sleep is interrupted by a signal and no exception is raised by the signal handler, the sleep is restarted with a recomputed timeout.

The suspension time may be longer than requested by an arbitrary amount, because of the scheduling of other activity in the system.

On Windows, if secs is zero, the thread relinquishes the remainder of its time slice to any other thread that is ready to run. If there are no other threads ready to run, the function returns immediately, and the thread continues execution. On Windows 8.1 and newer the implementation uses a high-resolution timer [https://learn.microsoft.com/windows-hardware/drivers/kernel/high-resolution-timers] which provides resolution of 100 nanoseconds. If secs is zero, Sleep(0) is used.

Unix implementation:

Use clock_nanosleep() if available (resolution: 1 nanosecond);

Or use nanosleep() if available (resolution: 1 nanosecond);

Or use select() (resolution: 1 microsecond).

Raises an auditing event time.sleep with argument secs.

버전 3.5에서 변경: 시그널 처리기가 예외를 발생시키는 경우를 제외하고, 시그널에 의해 휴면이 중단되더라도 이 함수는 이제 최소한 secs 동안 휴면합니다 (근거는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

버전 3.11에서 변경: On Unix, the clock_nanosleep() and nanosleep() functions are now used if available. On Windows, a waitable timer is now used.

버전 3.13에서 변경: Raises an auditing event.

time.strftime(format[, t])

gmtime()이나 localtime() 에 의해 반환된 시간을 나타내는 튜플이나 struct_time을 format 인자로 지정된 문자열로 변환합니다. t가 제공되지 않으면, localtime() 에서 반환된 현재 시각이 사용됩니다. format은 문자열이어야 합니다. t의 필드 중 어느 것이라도 허용 범위를 벗어나면 ValueError가 발생합니다.

0은 시간 튜플의 어느 위치에 대해서도 유효한 인자입니다; 그것이 일반적으로 유효하지 않으면 값이 올바른 값으로 강제 변환됩니다.

format 문자열은 다음 지시자(directives)를 포함할 수 있습니다. 선택적 필드 너비와 정밀도 명세 없이 표시되며, strftime() 결과에서 표시된 문자로 대체됩니다:

지시자

의미

노트

%a

로케일의 약식 요일 이름.

%A

로케일의 전체 요일 이름.

%b

로케일의 약식 월 이름.

%B

로케일의 전체 월 이름.

%c

로케일의 적절한 날짜와 시간 표현.

%d

월중 일(day of the month)을 십진수로 [01,31].

%f

Microseconds as a decimal number

[000000,999999].

(1)

%H

시(24시간제)를 십진수로 [00,23].

%I

시(12시간제)를 십진수로 [01,12].

%j

연중 일(day of the year)을 십진수로 [001,366].

%m

월을 십진수로 [01,12].

%M

분을 십진수로 [00,59].

%p

AM이나 PM에 해당하는 로케일의 값.

(2)

%S

초를 십진수로 [00,61].

(3)

%U

연중 주 번호(일요일이 주의 시작)를 십진수로 [00,53]. 첫 번째 일요일에 선행하는 새해의 모든 날은 주 0으로 간주합니다.

(4)

%u

Day of the week (Monday is 1; Sunday is 7) as a decimal number [1, 7].

%w

요일을 십진수로 [0(일요일),6].

%W

연중 주 번호(월요일이 주의 시작)를 십진수로 [00,53]. 첫 번째 월요일에 선행하는 새해의 모든 말은 주 0으로 간주합니다.

(4)

%x

로케일의 적절한 날짜 표현.

%X

로케일의 적절한 시간 표현.

%y

세기가 없는 해(year)를 십진수로 [00,99].

%Y

세기가 있는 해(year)를 십진수로.

%z

Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59]. [1]

%Z

Time zone name (no characters if no time zone exists). Deprecated. [1]

%G

ISO 8601 year (similar to %Y but follows the rules for the ISO 8601 calendar year). The year starts with the week that contains the first Thursday of the calendar year.

%V

ISO 8601 week number (as a decimal number [01,53]). The first week of the year is the one that contains the first Thursday of the year. Weeks start on Monday.

%%

리터럴 '%' 문자.

노트:

The %f format directive only applies to strptime(), not to strftime(). However, see also datetime.datetime.strptime() and datetime.datetime.strftime() where the %f format directive applies to microseconds.

strptime() 함수와 함께 사용할 때, %I 지시자를 사용하여 시(hour)를 구문 분석하면 %p 지시자는 출력 시(hour) 필드에만 영향을 줍니다.

범위는 실제로 0에서 61입니다; 값 60은 윤초 [https://en.wikipedia.org/wiki/Leap_second]를 나타내는 타임 스탬프에서 유효하고 값 61은 역사적 이유로 지원됩니다.

strptime() 함수와 함께 사용할 때, %U와 %W는 주중 일(day of the week)과 해(year)가 지정된 경우에만 계산에 사용됩니다.

Here is an example, a format for dates compatible with that specified in the RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] Internet email standard. [1]

>>> from time import gmtime, strftime
>>> strftime("%a, %d %b %Y %H:%M:%S +0000", gmtime())
'Thu, 28 Jun 2001 14:17:15 +0000'

특정 플랫폼에서는 추가 지시자가 지원될 수 있지만, 여기에 나열된 지시자에만 ANSI C에서 표준화된 의미가 있습니다. 플랫폼에서 지원되는 전체 포맷 코드 집합을 보려면, strftime(3) [https://manpages.debian.org/strftime(3)] 설명서를 참조하십시오.

일부 플랫폼에서, 선택적 필드 너비와 정밀도 명세는 지시자의 초기 '%' 뒤에 그 순서대로 나올 수 있습니다; 이것 또한 이식성이 없습니다. 필드 너비는 일반적으로 2이며, %j는 3입니다.

time.strptime(string[, format])

포맷(format)에 따라 시간을 나타내는 문자열을 구문 분석합니다. 반환 값은 gmtime()이나 localtime() 에 의해 반환되는 것과 같은 struct_time입니다.

format 매개 변수는 strftime()에서 사용된 것과 같은 지시자를 사용합니다; 기본값은 ctime()이 반환한 포맷과 일치하는 "%a %b %d %H:%M:%S %Y"입니다. format에 따라 string을 구문 분석할 수 없거나, 구문 분석 후 여분의 데이터가 있으면, ValueError가 발생합니다. 더 정확한 값을 유추할 수 없을 때 누락된 데이터를 채우는 데 사용되는 기본값은 (1900, 1, 1, 0, 0, 0, 0, 1, -1)입니다. string과 format은 모두 문자열이어야 합니다.

예를 들면:

>>> import time
>>> time.strptime("30 Nov 00", "%d %b %y")
time.struct_time(tm_year=2000, tm_mon=11, tm_mday=30, tm_hour=0, tm_min=0,
                 tm_sec=0, tm_wday=3, tm_yday=335, tm_isdst=-1)

%Z 지시자에 대한 지원은 tzname에 포함된 값과 daylight가 참인지를 기반으로 합니다. 이로 인해, 항상 알려진 (그리고 일광 절약 시간제가 아닌 시간대로 간주하는) UTC와 GMT를 인식하는 것을 제외하고는 플랫폼에 따라 다릅니다.

설명서에 지정된 지시자만 지원됩니다. strftime()은 플랫폼별로 구현되기 때문에 때로는 나열된 것보다 많은 지시자를 제공할 수 있습니다. 그러나 strptime()은 플랫폼과 독립적이라서 지원된다고 설명하지 않은 사용 가능한 모든 지시자를 반드시 지원하지는 않습니다.

class time.struct_time

gmtime(), localtime() 및 strptime()이 반환하는 시간 값 시퀀스의 형. 네임드 튜플 인터페이스를 갖는 객체입니다: 인덱스와 어트리뷰트 이름으로 값에 액세스 할 수 있습니다. 다음과 같은 값이 있습니다:

인덱스

어트리뷰트

값

0

tm_year

(예를 들어, 1993)

1

tm_mon

범위 [1, 12]

2

tm_mday

범위 [1, 31]

3

tm_hour

범위 [0, 23]

4

tm_min

범위 [0, 59]

5

tm_sec

range [0, 61]; see Note (2) in strftime()

6

tm_wday

range [0, 6]; Monday is 0

7

tm_yday

범위 [1, 366]

8

tm_isdst

0, 1 또는 -1; 아래를 참조하십시오

해당 없음

tm_zone

시간대 이름의 약어

해당 없음

tm_gmtoff

UTC에서 동쪽으로 초 단위 오프셋

C 구조체와 달리, 월 값의 범위는 [0, 11]이 아니라 [1, 12] 임에 유의하십시오.

mktime() 호출에서, 일광 절약 시간제가 발효 중이면 tm_isdst가 1로 설정되고, 그렇지 않으면 0으로 설정될 수 있습니다. 값이 -1이면 알 수 없다는 뜻이고, 일반적으로 올바른 상태가 채워집니다.

길이가 잘못된 튜플이 struct_time을 기대하는 함수에 전달되거나, 잘못된 형의 요소가 있으면, TypeError가 발생합니다.

time.time() → float

Return the time in seconds since the epoch as a floating-point number. The handling of leap seconds [https://en.wikipedia.org/wiki/Leap_second] is platform dependent. On Windows and most Unix systems, the leap seconds are not counted towards the time in seconds since the epoch. This is commonly referred to as Unix time [https://en.wikipedia.org/wiki/Unix_time].

Note that even though the time is always returned as a floating-point number, not all systems provide time with a better precision than 1 second. While this function normally returns non-decreasing values, it can return a lower value than a previous call if the system clock has been set back between the two calls.

time()에 의해 반환된 숫자는 더 일반적인 시간 형식(즉 년, 월, 일, 시 등…)으로 변환될 수 있는데, gmtime() 함수에 전달하여 UTC로, localtime() 함수에 전달하여 현지 시간으로 변환할 수 있습니다. 두 경우 모두 달력 날짜의 구성 요소를 어트리뷰트로 액세스 할 수 있는 struct_time 객체가 반환됩니다.

Clock:

On Windows, call GetSystemTimeAsFileTime().

Call clock_gettime(CLOCK_REALTIME) if available.

Otherwise, call gettimeofday().

Use time_ns() to avoid the precision loss caused by the float type.

time.time_ns() → int

time()과 비슷하지만, 시간을 에포크 이후의 나노초를 나타내는 정수로 반환합니다.

Added in version 3.7.

time.thread_time() → float

현재 스레드의 시스템과 사용자 CPU 시간 합계의 값을 (소수부가 있는 초로) 반환합니다. 수면 중에 지난 시간은 포함되지 않습니다. 정의상 스레드 수준입니다. 반환된 값의 기준점은 정의되어 있지 않아서, 같은 스레드에서 이루어지는 두 호출 결과 간의 차이만 유효합니다.

Use thread_time_ns() to avoid the precision loss caused by the float type.

Availability: Linux, Unix, Windows.

Unix systems supporting CLOCK_THREAD_CPUTIME_ID.

Added in version 3.7.

time.thread_time_ns() → int

thread_time()과 비슷하지만, 시간을 나노초로 반환합니다.

Added in version 3.7.

time.tzset()

라이브러리 루틴이 사용하는 시간 변환 규칙을 재설정합니다. 환경 변수 TZ는 이것이 수행되는 방법을 지정합니다. 또한 변수 tzname (TZ 환경 변수에서), timezone (UTC에서 서쪽으로 DST가 아닌 초), altzone (UTC에서 서쪽으로 DST 초) 및 daylight (이 시간대가 일광 절약 시간 규칙이 없으면 0으로, 일광 절약 시간이 적용될 때 시간, 과거, 현재 또는 미래가 있으면 0이 아닌 값으로)를 설정합니다.

Availability: Unix.

참고

많은 경우에, TZ 환경 변수를 변경하면 tzset()을 호출하지 않고도 localtime() 과 같은 함수의 출력에 영향을 줄 수 있지만, 이 동작에 의존해서는 안 됩니다.

TZ 환경 변수에는 공백이 없어야 합니다.

TZ 환경 변수의 표준 형식은 다음과 같습니다 (명확함을 위해 공백을 추가했습니다):

std offset [dst [offset [,start[/time], end[/time]]]]

구성 요소는 다음과 같습니다:

std와 dst

시간대 약어를 제공하는 세 개 이상의 영숫자. 이들은 time.tzname으로 전파됩니다

offset

오프셋은 다음과 같은 형식입니다: ± hh[:mm[:ss]]. UTC에 도달하기 위해 현지 시간에 더하는 값을 나타냅니다. 앞에 ‘-‘가 있으면, 시간대는 본초 자오선(Prime Meridian)의 동쪽입니다; 그렇지 않으면, 서쪽입니다. dst 다음에 오프셋이 없으면, 일광 절약 시간은 표준 시간보다 1시간 빠르다고 가정합니다.

start[/time], end[/time]

언제 DST로 변경하고, 언제 돌아오는지를 나타냅니다. 시작(start) 날짜와 종료(end) 날짜의 형식은 다음 중 하나입니다:

Jn

율리우스 일 n (1 <= n <= 365). 윤일(leap days)은 계산되지 않아서, 모든 연도에서 2월 28일은 59일이고 3월 1일은 60일입니다.

n

0부터 시작하는 율리우스 일 (0 <= n <= 365). 윤일(leap days)이 계산되며, 2월 29일을 가리킬 수 있습니다.

Mm.n.d

연중 월 m의 주 n의 d번째 요일 (0 <= d <= 6, 1 <= n <= 5, 1 <= m <= 12, 여기서 주 5는 “월 m의 마지막 d 요일”을 뜻하는데, 4번째나 5번째 주에 발생할 수 있습니다). 주 1은 d번째 요일이 등장하는 첫 주입니다. 요일 0은 일요일입니다.

time은 선행 부호(‘-‘나 ‘+’)가 허용되지 않는다는 점을 제외하고 offset과 형식이 같습니다. time이 제공되지 않으면, 기본값은 02:00:00입니다.

>>> os.environ['TZ'] = 'EST+05EDT,M4.1.0,M10.5.0'
>>> time.tzset()
>>> time.strftime('%X %x %Z')
'02:07:36 05/08/03 EDT'
>>> os.environ['TZ'] = 'AEST-10AEDT-11,M10.5.0,M3.5.0'
>>> time.tzset()
>>> time.strftime('%X %x %Z')
'16:08:12 05/08/03 AEST'

많은 유닉스 시스템(*BSD, 리눅스, Solaris 및 Darwin을 포함합니다)에서, 시스템의 zoneinfo (tzfile(5) [https://manpages.debian.org/tzfile(5)]) 데이터베이스를 사용하여 시간대 규칙을 지정하는 것이 더 편리합니다. 이렇게 하려면, TZ 환경 변수를 시스템 ‘zoneinfo’ 시간대 데이터베이스의 루트(일반적으로 /usr/share/zoneinfo에 있습니다)에 상대적인 필요한 시간대 데이터 파일의 경로로 설정하십시오. 예를 들어, 'US/Eastern', 'Australia/Melbourne', 'Egypt' 또는 'Europe/Amsterdam'.

>>> os.environ['TZ'] = 'US/Eastern'
>>> time.tzset()
>>> time.tzname
('EST', 'EDT')
>>> os.environ['TZ'] = 'Egypt'
>>> time.tzset()
>>> time.tzname
('EET', 'EEST')

시계 ID 상수

이 상수들은 clock_getres()와 clock_gettime()의 매개 변수로 사용됩니다.

time.CLOCK_BOOTTIME

CLOCK_MONOTONIC과 동일하지만, 시스템이 일시 중단된 시간도 포함합니다.

이를 통해 응용 프로그램은 settimeofday() 등을 사용하여 시간이 변경되면 불연속성이 발생할 수 있는 CLOCK_REALTIME의 복잡함을 다루지 않고도 일시 중단을 인식하는 단조 시계를 얻을 수 있습니다.

Availability: Linux >= 2.6.39.

Added in version 3.7.

time.CLOCK_HIGHRES

Solaris OS에는 최적의 하드웨어 소스를 사용하려고 하는 CLOCK_HIGHRES 타이머가 있으며, 나노초에 가까운 해상도를 제공합니다. CLOCK_HIGHRES는 조정 불가능한 고해상도 시계입니다.

Availability: Solaris.

Added in version 3.3.

time.CLOCK_MONOTONIC

설정할 수 없고 어떤 지정되지 않은 시작점 이후의 단조 시간을 나타내는 시계.

Availability: Unix.

Added in version 3.3.

time.CLOCK_MONOTONIC_RAW

CLOCK_MONOTONIC과 비슷하지만, NTP 조정이 적용되지 않는 원시 하드웨어 기반 시간에 대한 액세스를 제공합니다.

Availability: Linux >= 2.6.28, macOS >= 10.12.

Added in version 3.3.

time.CLOCK_MONOTONIC_RAW_APPROX

Similar to CLOCK_MONOTONIC_RAW, but reads a value cached by the system at context switch and hence has less accuracy.

Availability: macOS >= 10.12.

Added in version 3.13.

time.CLOCK_PROCESS_CPUTIME_ID

CPU의 고해상도 프로세스별 타이머.

Availability: Unix.

Added in version 3.3.

time.CLOCK_PROF

CPU의 고해상도 프로세스별 타이머.

Availability: FreeBSD, NetBSD >= 7, OpenBSD.

Added in version 3.7.

time.CLOCK_TAI

국제원자시(International Atomic Time) [https://www.nist.gov/pml/time-and-frequency-division/nist-time-frequently-asked-questions-faq#tai]

이것이 정확한 답을 주려면 시스템에 최신 윤초 표가 있어야 합니다. PTP나 NTP 소프트웨어는 윤초 표를 유지할 수 있습니다.

Availability: Linux.

Added in version 3.9.

time.CLOCK_THREAD_CPUTIME_ID

스레드별 CPU 시간 시계.

Availability: Unix.

Added in version 3.3.

time.CLOCK_UPTIME

절댓값이 시스템이 실행되고 정지되지 않은 시간인 시간, 절대와 간격 모두로, 정확한 가동 시간 측정을 제공합니다.

Availability: FreeBSD, OpenBSD >= 5.5.

Added in version 3.7.

time.CLOCK_UPTIME_RAW

주파수나 시간 조정에 영향을 받지 않고 시스템이 휴면하는 중에는 증가하지 않는 임의의 지점 이후의 시간을 추적하면서 단조 증가 하는 시계.

Availability: macOS >= 10.12.

Added in version 3.8.

time.CLOCK_UPTIME_RAW_APPROX

Like CLOCK_UPTIME_RAW, but the value is cached by the system at context switches and therefore has less accuracy.

Availability: macOS >= 10.12.

Added in version 3.13.

다음 상수는 clock_settime()에 보낼 수 있는 유일한 매개 변수입니다.

time.CLOCK_REALTIME

시스템 수준의 실시간 시계. 이 시계를 설정하려면 적절한 권한이 필요합니다.

Availability: Unix.

Added in version 3.3.

시간대 상수

time.altzone

정의된 것이 있다면, 현지 DST 시간대의 UTC 서쪽으로 초 단위 오프셋. 현지 DST 시간대가 UTC 동쪽이면 음수입니다 (영국을 포함한 서유럽의 경우). daylight가 0이 아닌 경우에만 사용하십시오. 아래 참고 사항을 참조하십시오.

time.daylight

DST 시간대가 정의되면 0이 아닙니다. 아래 참고 사항을 참조하십시오.

time.timezone

UTC 서쪽으로 초 단위의, 현지 (DST가 아닌) 시간대의 오프셋 (대부분 서부 유럽 지역에서는 음수, 미국에서는 양수, 영국에서는 0). 아래 참고 사항을 참조하십시오.

time.tzname

두 문자열의 튜플: 첫 번째는 현지 DST가 아닌 시간대의 이름이고, 두 번째는 현지 DST 시간대의 이름입니다. DST 시간대가 정의되어 있지 않으면, 두 번째 문자열을 사용하지 않아야 합니다. 아래 참고 사항을 참조하십시오.

참고

For the above Timezone constants (altzone, daylight, timezone, and tzname), the value is determined by the timezone rules in effect at module load time or the last time tzset() is called and may be incorrect for times in the past. It is recommended to use the tm_gmtoff and tm_zone results from localtime() to obtain timezone information.

더 보기

모듈 datetime

날짜와 시간에 대한 더 객체 지향적인 인터페이스.

모듈 locale

국제화 서비스. 로케일 설정은 strftime()과 strptime()의 많은 포맷 지시자의 해석에 영향을 줍니다.

모듈 calendar

일반적인 캘린더 관련 함수. timegm()은 이 모듈에 있는 gmtime()의 역함수입니다.

각주

[1] (1,2,3)

The use of %Z is now deprecated, but the %z escape that expands to the preferred hour/minute offset is not supported by all ANSI C libraries. Also, a strict reading of the original 1982 RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] standard calls for a two-digit year (%y rather than %Y), but practice moved to 4-digit years long before the year 2000. After that, RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] became obsolete and the 4-digit year has been first recommended by RFC 1123 [https://datatracker.ietf.org/doc/html/rfc1123.html] and then mandated by RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html].

argparse — Parser for command-line options, arguments and subcommands

Added in version 3.2.

소스 코드: Lib/argparse.py [https://github.com/python/cpython/tree/main/Lib/argparse.py]

자습서

이 페이지는 API 레퍼런스 정보를 담고 있습니다. 파이썬 명령행 파싱에 대한 더 친절한 소개를 원하시면, argparse 자습서 를 보십시오.

The argparse module makes it easy to write user-friendly command-line interfaces. The program defines what arguments it requires, and argparse will figure out how to parse those out of sys.argv. The argparse module also automatically generates help and usage messages. The module will also issue errors when users give the program invalid arguments.

The argparse module’s support for command-line interfaces is built around an instance of argparse.ArgumentParser. It is a container for argument specifications and has options that apply to the parser as whole:

parser = argparse.ArgumentParser(
                    prog='ProgramName',
                    description='What the program does',
                    epilog='Text at the bottom of help')

The ArgumentParser.add_argument() method attaches individual argument specifications to the parser. It supports positional arguments, options that accept values, and on/off flags:

parser.add_argument('filename')           # positional argument
parser.add_argument('-c', '--count')      # option that takes a value
parser.add_argument('-v', '--verbose',
                    action='store_true')  # on/off flag

The ArgumentParser.parse_args() method runs the parser and places the extracted data in a argparse.Namespace object:

args = parser.parse_args()
print(args.filename, args.count, args.verbose)

참고

If you’re looking for a guide about how to upgrade optparse code to argparse, see Upgrading Optparse Code.

ArgumentParser 객체

class argparse.ArgumentParser(prog=None, usage=None, description=None, epilog=None, parents=[], formatter_class=argparse.HelpFormatter, prefix_chars='-', fromfile_prefix_chars=None, argument_default=None, conflict_handler='error', add_help=True, allow_abbrev=True, exit_on_error=True, suggest_on_error=False)

새로운 ArgumentParser 객체를 만듭니다. 모든 매개 변수는 키워드 인자로 전달되어야 합니다. 매개 변수마다 아래에서 더 자세히 설명되지만, 요약하면 다음과 같습니다:

prog - The name of the program (default: generated from the __main__ module attributes and sys.argv[0])

usage - 프로그램 사용법을 설명하는 문자열 (기본값: 파서에 추가된 인자로부터 만들어지는 값)

description - Text to display before the argument help (by default, no text)

epilog - Text to display after the argument help (by default, no text)

parents - ArgumentParser 객체들의 리스트이고, 이 들의 인자들도 포함된다

formatter_class - 도움말 출력을 사용자 정의하기 위한 클래스

prefix_chars - 선택 인자 앞에 붙는 문자 집합 (기본값: ‘-‘).

fromfile_prefix_chars - 추가 인자를 읽어야 하는 파일 앞에 붙는 문자 집합 (기본값: None).

argument_default - 인자의 전역 기본값 (기본값: None)

conflict_handler - 충돌하는 선택 사항을 해결하기 위한 전략 (일반적으로 불필요함)

add_help - 파서에 -h/--help 옵션을 추가합니다 (기본값: True)

allow_abbrev - 약어가 모호하지 않으면 긴 옵션을 축약할 수 있도록 합니다. (기본값: True)

exit_on_error - Determines whether or not ArgumentParser exits with error info when an error occurs. (default: True)

suggest_on_error - Enables suggestions for mistyped argument choices and subparser names (default: False)

버전 3.5에서 변경: allow_abbrev 매개 변수가 추가되었습니다.

버전 3.8에서 변경: 이전 버전에서는, allow_abbrev는 -vv가 -v -v를 뜻하는 것과 같은 짧은 플래그의 그룹화도 비활성화했습니다.

버전 3.9에서 변경: exit_on_error 매개 변수가 추가되었습니다.

다음 절에서는 이들 각각의 사용 방법에 관해 설명합니다.

prog

By default, ArgumentParser calculates the name of the program to display in help messages depending on the way the Python interpreter was run:

The base name of sys.argv[0] if a file was passed as argument.

The Python interpreter name followed by sys.argv[0] if a directory or a zipfile was passed as argument.

The Python interpreter name followed by -m followed by the module or package name if the -m option was used.

This default is almost always desirable because it will make the help messages match the string that was used to invoke the program on the command line. However, to change this default behavior, another value can be supplied using the prog= argument to ArgumentParser:

>>> parser = argparse.ArgumentParser(prog='myprogram')
>>> parser.print_help()
usage: myprogram [-h]

options:
 -h, --help  show this help message and exit

Note that the program name, whether determined from sys.argv[0], from the __main__ module attributes or from the prog= argument, is available to help messages using the %(prog)s format specifier.

>>> parser = argparse.ArgumentParser(prog='myprogram')
>>> parser.add_argument('--foo', help='foo of the %(prog)s program')
>>> parser.print_help()
usage: myprogram [-h] [--foo FOO]

options:
 -h, --help  show this help message and exit
 --foo FOO   foo of the myprogram program

버전 3.14에서 변경: The default prog value now reflects how __main__ was actually executed, rather than always being os.path.basename(sys.argv[0]).

usage

By default, ArgumentParser calculates the usage message from the arguments it contains. The default message can be overridden with the usage= keyword argument:

>>> parser = argparse.ArgumentParser(prog='PROG', usage='%(prog)s [options]')
>>> parser.add_argument('--foo', nargs='?', help='foo help')
>>> parser.add_argument('bar', nargs='+', help='bar help')
>>> parser.print_help()
usage: PROG [options]

positional arguments:
 bar          bar help

options:
 -h, --help   show this help message and exit
 --foo [FOO]  foo help

%(prog)s 포맷 지정자는 사용법 메시지에서 프로그램 이름을 채울 때 사용할 수 있습니다.

When a custom usage message is specified for the main parser, you may also want to consider passing the prog argument to add_subparsers() or the prog and the usage arguments to add_parser(), to ensure consistent command prefixes and usage information across subparsers.

description

Most calls to the ArgumentParser constructor will use the description= keyword argument. This argument gives a brief description of what the program does and how it works. In help messages, the description is displayed between the command-line usage string and the help messages for the various arguments.

기본적으로, 설명은 주어진 공간에 맞도록 줄 바꿈 됩니다. 이 동작을 변경하려면 formatter_class 인자를 참조하십시오.

epilog

일부 프로그램은 인자에 대한 설명 뒤에 프로그램에 대한 추가 설명을 표시하려고 합니다. 이러한 텍스트는 epilog= 에 대한 인자를 ArgumentParser 에 사용하여 지정할 수 있습니다:

>>> parser = argparse.ArgumentParser(
...     description='A foo that bars',
...     epilog="And that's how you'd foo a bar")
>>> parser.print_help()
usage: argparse.py [-h]

A foo that bars

options:
 -h, --help  show this help message and exit

And that's how you'd foo a bar

description 인자와 마찬가지로, epilog= 텍스트가 기본적으로 줄 바꿈 됩니다만, 이 동작은 formatter_class 인자를 ArgumentParser 에 제공해서 조정할 수 있습니다.

parents

때로는 여러 파서가 공통 인자 집합을 공유하는 경우가 있습니다. 이러한 인자의 정의를 반복하는 대신, 모든 공유 인자를 갖는 파서를 ArgumentParser 에 parents= 인자로 전달할 수 있습니다. parents= 인자는 ArgumentParser 객체의 리스트를 취하여, 그것들로부터 모든 위치와 선택 액션을 수집해서 새로 만들어지는 ArgumentParser 객체에 추가합니다:

>>> parent_parser = argparse.ArgumentParser(add_help=False)
>>> parent_parser.add_argument('--parent', type=int)

>>> foo_parser = argparse.ArgumentParser(parents=[parent_parser])
>>> foo_parser.add_argument('foo')
>>> foo_parser.parse_args(['--parent', '2', 'XXX'])
Namespace(foo='XXX', parent=2)

>>> bar_parser = argparse.ArgumentParser(parents=[parent_parser])
>>> bar_parser.add_argument('--bar')
>>> bar_parser.parse_args(['--bar', 'YYY'])
Namespace(bar='YYY', parent=None)

대부분의 부모 파서는 add_help=False 를 지정합니다. 그렇지 않으면, ArgumentParser 는 (하나는 부모에, 하나는 자식에 있는) 두 개의 -h/--help 옵션을 보게 될 것이고, 에러를 발생시킵니다.

참고

parents= 를 통해 전달하기 전에 파서를 완전히 초기화해야 합니다. 자식 파서 다음에 부모 파서를 변경하면 자식에 반영되지 않습니다.

formatter_class

ArgumentParser 객체는 대체 포매팅 클래스를 지정함으로써 도움말 포매팅을 사용자 정의 할 수 있도록 합니다. 현재 네 가지 클래스가 있습니다:

class argparse.RawDescriptionHelpFormatter

class argparse.RawTextHelpFormatter

class argparse.ArgumentDefaultsHelpFormatter

class argparse.MetavarTypeHelpFormatter

RawDescriptionHelpFormatter 와 RawTextHelpFormatter 는 텍스트 설명이 표시되는 방법을 더 제어할 수 있도록 합니다. 기본적으로, ArgumentParser 객체는 명령행 도움말 메시지에서 description 및 epilog 텍스트를 줄 바꿈 합니다.:

>>> parser = argparse.ArgumentParser(
...     prog='PROG',
...     description='''this description
...         was indented weird
...             but that is okay''',
...     epilog='''
...             likewise for this epilog whose whitespace will
...         be cleaned up and whose words will be wrapped
...         across a couple lines''')
>>> parser.print_help()
usage: PROG [-h]

this description was indented weird but that is okay

options:
 -h, --help  show this help message and exit

likewise for this epilog whose whitespace will be cleaned up and whose words
will be wrapped across a couple lines

RawDescriptionHelpFormatter 를 formatter_class= 로 전달하는 것은 description 과 epilog 가 이미 올바르게 포맷되어 있어서 줄 바꿈 되어서는 안 된다는 것을 가리킵니다:

>>> parser = argparse.ArgumentParser(
...     prog='PROG',
...     formatter_class=argparse.RawDescriptionHelpFormatter,
...     description=textwrap.dedent('''\
...         Please do not mess up this text!
...         --------------------------------
...             I have indented it
...             exactly the way
...             I want it
...         '''))
>>> parser.print_help()
usage: PROG [-h]

Please do not mess up this text!
--------------------------------
   I have indented it
   exactly the way
   I want it

options:
 -h, --help  show this help message and exit

RawTextHelpFormatter maintains whitespace for all sorts of help text, including argument descriptions. However, multiple newlines are replaced with one. If you wish to preserve multiple blank lines, add spaces between the newlines.

ArgumentDefaultsHelpFormatter 는 기본값에 대한 정보를 각각의 인자 도움말 메시지에 자동으로 추가합니다:

>>> parser = argparse.ArgumentParser(
...     prog='PROG',
...     formatter_class=argparse.ArgumentDefaultsHelpFormatter)
>>> parser.add_argument('--foo', type=int, default=42, help='FOO!')
>>> parser.add_argument('bar', nargs='*', default=[1, 2, 3], help='BAR!')
>>> parser.print_help()
usage: PROG [-h] [--foo FOO] [bar ...]

positional arguments:
 bar         BAR! (default: [1, 2, 3])

options:
 -h, --help  show this help message and exit
 --foo FOO   FOO! (default: 42)

MetavarTypeHelpFormatter 는 각 인자 값의 표시 이름으로 (일반 포매터처럼 dest 를 사용하는 대신에) type 인자의 이름을 사용합니다:

>>> parser = argparse.ArgumentParser(
...     prog='PROG',
...     formatter_class=argparse.MetavarTypeHelpFormatter)
>>> parser.add_argument('--foo', type=int)
>>> parser.add_argument('bar', type=float)
>>> parser.print_help()
usage: PROG [-h] [--foo int] float

positional arguments:
  float

options:
  -h, --help  show this help message and exit
  --foo int

prefix_chars

Most command-line options will use - as the prefix, e.g. -f/--foo. Parsers that need to support different or additional prefix characters, e.g. for options like +f or /foo, may specify them using the prefix_chars= argument to the ArgumentParser constructor:

>>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='-+')
>>> parser.add_argument('+f')
>>> parser.add_argument('++bar')
>>> parser.parse_args('+f X ++bar Y'.split())
Namespace(bar='Y', f='X')

prefix_chars= 인자의 기본값은 '-' 입니다. - 를 포함하지 않는 문자 집합을 제공하면 -f/--foo 옵션이 허용되지 않게 됩니다.

fromfile_prefix_chars

Sometimes, when dealing with a particularly long argument list, it may make sense to keep the list of arguments in a file rather than typing it out at the command line. If the fromfile_prefix_chars= argument is given to the ArgumentParser constructor, then arguments that start with any of the specified characters will be treated as files, and will be replaced by the arguments they contain. For example:

>>> with open('args.txt', 'w', encoding=sys.getfilesystemencoding()) as fp:
...     fp.write('-f\nbar')
...
>>> parser = argparse.ArgumentParser(fromfile_prefix_chars='@')
>>> parser.add_argument('-f')
>>> parser.parse_args(['-f', 'foo', '@args.txt'])
Namespace(f='bar')

파일에서 읽은 인자는 기본적으로 한 줄에 하나씩 있어야 하고 (하지만 convert_arg_line_to_args() 도 참조하십시오), 명령행에서 원래 파일을 참조하는 인자와 같은 위치에 있는 것처럼 처리됩니다. 위의 예에서 표현식 ['-f', 'foo', '@args.txt'] 는 ['-f', 'foo', '-f', 'bar'] 와 동등하게 취급됩니다.

ArgumentParser uses filesystem encoding and error handler to read the file containing arguments.

fromfile_prefix_chars= 인자의 기본값은 None 입니다. 이것은 인자가 절대로 파일 참조로 취급되지 않는다는 것을 의미합니다.

버전 3.12에서 변경: ArgumentParser changed encoding and errors to read arguments files from default (e.g. locale.getpreferredencoding(False) and "strict") to the filesystem encoding and error handler. Arguments file should be encoded in UTF-8 instead of ANSI Codepage on Windows.

argument_default

일반적으로 인자의 기본값은 add_argument() 에 기본값을 전달하거나 특정 이름-값 쌍 집합을 사용하여 set_defaults() 메서드를 호출하여 지정됩니다. 그러나 때로는, 파서 전체에 적용되는 단일 기본값을 지정하는 것이 유용 할 수 있습니다. 이것은 argument_default= 키워드 인자를 ArgumentParser 에 전달함으로써 이루어질 수 있습니다. 예를 들어, parse_args() 호출에서 어트리뷰트 생성을 전역적으로 억제하려면, argument_default=SUPPRESS 를 제공합니다:

>>> parser = argparse.ArgumentParser(argument_default=argparse.SUPPRESS)
>>> parser.add_argument('--foo')
>>> parser.add_argument('bar', nargs='?')
>>> parser.parse_args(['--foo', '1', 'BAR'])
Namespace(bar='BAR', foo='1')
>>> parser.parse_args([])
Namespace()

allow_abbrev

일반적으로 ArgumentParser 의 parse_args() 메서드에 인자 리스트를 건네주면 긴 옵션의 약어를 인식합니다.

allow_abbrev 를 False 로 설정하면 이 기능을 비활성화 할 수 있습니다:

>>> parser = argparse.ArgumentParser(prog='PROG', allow_abbrev=False)
>>> parser.add_argument('--foobar', action='store_true')
>>> parser.add_argument('--foonley', action='store_false')
>>> parser.parse_args(['--foon'])
usage: PROG [-h] [--foobar] [--foonley]
PROG: error: unrecognized arguments: --foon

Added in version 3.5.

conflict_handler

ArgumentParser 객체는 같은 옵션 문자열을 가진 두 개의 액션을 허용하지 않습니다. 기본적으로 ArgumentParser 객체는 이미 사용 중인 옵션 문자열로 인자를 만들려고 시도하면 예외를 발생시킵니다

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-f', '--foo', help='old foo help')
>>> parser.add_argument('--foo', help='new foo help')
Traceback (most recent call last):
 ..
ArgumentError: argument --foo: conflicting option string(s): --foo

때로는 (예를 들어 parents 를 사용하는 경우) 같은 옵션 문자열을 갖는 예전의 인자들을 간단히 대체하는 것이 유용 할 수 있습니다. 이 동작을 얻으려면, ArgumentParser 의 conflict_handler= 인자에 'resolve' 값을 제공합니다:

>>> parser = argparse.ArgumentParser(prog='PROG', conflict_handler='resolve')
>>> parser.add_argument('-f', '--foo', help='old foo help')
>>> parser.add_argument('--foo', help='new foo help')
>>> parser.print_help()
usage: PROG [-h] [-f FOO] [--foo FOO]

options:
 -h, --help  show this help message and exit
 -f FOO      old foo help
 --foo FOO   new foo help

ArgumentParser 객체는 모든 옵션 문자열이 재정의된 경우에만 액션을 제거합니다. 위의 예에서, 이전의 -f/--foo 액션은 --foo 옵션 문자열만 재정의되었기 때문에 -f 액션으로 유지됩니다.

add_help

By default, ArgumentParser objects add an option which simply displays the parser’s help message. If -h or --help is supplied at the command line, the ArgumentParser help will be printed.

때에 따라, 이 도움말 옵션을 추가하지 않도록 설정하는 것이 유용 할 수 있습니다. add_help= 인자를 False 로 ArgumentParser 에 전달하면 됩니다:

>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
>>> parser.add_argument('--foo', help='foo help')
>>> parser.print_help()
usage: PROG [--foo FOO]

options:
 --foo FOO  foo help

도움말 옵션은 일반적으로 -h/--help 입니다. 예외는 prefix_chars= 가 지정되고 - 을 포함하지 않는 경우입니다. 이 경우 -h 와 --help 는 유효한 옵션이 아닙니다. 이 경우, prefix_chars 의 첫 번째 문자가 도움말 옵션 접두어로 사용됩니다:

>>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='+/')
>>> parser.print_help()
usage: PROG [+h]

options:
  +h, ++help  show this help message and exit

exit_on_error

Normally, when you pass an invalid argument list to the parse_args() method of an ArgumentParser, it will print a message to sys.stderr and exit with a status code of 2.

If the user would like to catch errors manually, the feature can be enabled by setting exit_on_error to False:

>>> parser = argparse.ArgumentParser(exit_on_error=False)
>>> parser.add_argument('--integers', type=int)
_StoreAction(option_strings=['--integers'], dest='integers', nargs=None, const=None, default=None, type=<class 'int'>, choices=None, help=None, metavar=None)
>>> try:
...     parser.parse_args('--integers a'.split())
... except argparse.ArgumentError:
...     print('Catching an argumentError')
...
Catching an argumentError

Added in version 3.9.

suggest_on_error

By default, when a user passes an invalid argument choice or subparser name, ArgumentParser will exit with error info and list the permissible argument choices (if specified) or subparser names as part of the error message.

If the user would like to enable suggestions for mistyped argument choices and subparser names, the feature can be enabled by setting suggest_on_error to True. Note that this only applies for arguments when the choices specified are strings:

>>> parser = argparse.ArgumentParser(description='Process some integers.', suggest_on_error=True)
>>> parser.add_argument('--action', choices=['sum', 'max'])
>>> parser.add_argument('integers', metavar='N', type=int, nargs='+',
...                     help='an integer for the accumulator')
>>> parser.parse_args(['--action', 'sumn', 1, 2, 3])
tester.py: error: argument --action: invalid choice: 'sumn', maybe you meant 'sum'? (choose from 'sum', 'max')

If you’re writing code that needs to be compatible with older Python versions and want to opportunistically use suggest_on_error when it’s available, you can set it as an attribute after initializing the parser instead of using the keyword argument:

>>> parser = argparse.ArgumentParser(description='Process some integers.')
>>> parser.suggest_on_error = True

Added in version 3.14.

add_argument() 메서드

ArgumentParser.add_argument(name or flags..., *[, action][, nargs][, const][, default][, type][, choices][, required][, help][, metavar][, dest][, deprecated])

단일 명령행 인자를 구문 분석하는 방법을 정의합니다. 매개 변수마다 아래에서 더 자세히 설명되지만, 요약하면 다음과 같습니다:

name or flags - Either a name or a list of option strings, e.g. 'foo' or '-f', '--foo'.

action - 명령행에서 이 인자가 발견될 때 수행 할 액션의 기본형.

nargs - 소비되어야 하는 명령행 인자의 수.

const - 일부 action 및 nargs 를 선택할 때 필요한 상숫값.

default - 인자가 명령행에 없고 namespace 객체에 없으면 생성되는 값.

type - 명령행 인자가 변환되어야 할 형.

choices - A sequence of the allowable values for the argument.

required - 명령행 옵션을 생략 할 수 있는지 아닌지 (선택적일 때만).

help - 인자가 하는 일에 대한 간단한 설명.

metavar - 사용 메시지에 사용되는 인자의 이름.

dest - parse_args() 가 반환하는 객체에 추가될 어트리뷰트의 이름.

deprecated - Whether or not use of the argument is deprecated.

다음 절에서는 이들 각각의 사용 방법에 관해 설명합니다.

name or flags

The add_argument() method must know whether an optional argument, like -f or --foo, or a positional argument, like a list of filenames, is expected. The first arguments passed to add_argument() must therefore be either a series of flags, or a simple argument name.

For example, an optional argument could be created like:

>>> parser.add_argument('-f', '--foo')

반면에 위치 인자는 이렇게 만들어집니다:

>>> parser.add_argument('bar')

parse_args() 가 호출되면, 선택 인자는 - 접두사로 식별되고, 그 밖의 인자는 위치 인자로 간주합니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-f', '--foo')
>>> parser.add_argument('bar')
>>> parser.parse_args(['BAR'])
Namespace(bar='BAR', foo=None)
>>> parser.parse_args(['BAR', '--foo', 'FOO'])
Namespace(bar='BAR', foo='FOO')
>>> parser.parse_args(['--foo', 'FOO'])
usage: PROG [-h] [-f FOO] bar
PROG: error: the following arguments are required: bar

By default, argparse automatically handles the internal naming and display names of arguments, simplifying the process without requiring additional configuration. As such, you do not need to specify the dest and metavar parameters. The dest parameter defaults to the argument name with underscores _ replacing hyphens - . The metavar parameter defaults to the upper-cased name. For example:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('--foo-bar')
>>> parser.parse_args(['--foo-bar', 'FOO-BAR']
Namespace(foo_bar='FOO-BAR')
>>> parser.print_help()
usage:  [-h] [--foo-bar FOO-BAR]

optional arguments:
 -h, --help  show this help message and exit
 --foo-bar FOO-BAR

action

ArgumentParser 객체는 명령행 인자를 액션과 연관시킵니다. 대부분의 액션은 단순히 parse_args() 에 의해 반환된 객체에 어트리뷰트를 추가하기만 하지만, 액션은 관련된 명령행 인자로 무엇이든 할 수 있습니다. action 키워드 인자는 명령행 인자의 처리 방법을 지정합니다. 제공되는 액션은 다음과 같습니다:

'store' - This just stores the argument’s value. This is the default action.

'store_const' - This stores the value specified by the const keyword argument; note that the const keyword argument defaults to None. The 'store_const' action is most commonly used with optional arguments that specify some sort of flag. For example:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action='store_const', const=42)
>>> parser.parse_args(['--foo'])
Namespace(foo=42)

'store_true' and 'store_false' - These are special cases of 'store_const' used for storing the values True and False respectively. In addition, they create default values of False and True respectively:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action='store_true')
>>> parser.add_argument('--bar', action='store_false')
>>> parser.add_argument('--baz', action='store_false')
>>> parser.parse_args('--foo --bar'.split())
Namespace(foo=True, bar=False, baz=True)

'append' - This stores a list, and appends each argument value to the list. It is useful to allow an option to be specified multiple times. If the default value is non-empty, the default elements will be present in the parsed value for the option, with any values from the command line appended after those default values. Example usage:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action='append')
>>> parser.parse_args('--foo 1 --foo 2'.split())
Namespace(foo=['1', '2'])

'append_const' - This stores a list, and appends the value specified by the const keyword argument to the list; note that the const keyword argument defaults to None. The 'append_const' action is typically useful when multiple arguments need to store constants to the same list. For example:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--str', dest='types', action='append_const', const=str)
>>> parser.add_argument('--int', dest='types', action='append_const', const=int)
>>> parser.parse_args('--str --int'.split())
Namespace(types=[<class 'str'>, <class 'int'>])

'extend' - This stores a list and appends each item from the multi-value argument list to it. The 'extend' action is typically used with the nargs keyword argument value '+' or '*'. Note that when nargs is None (the default) or '?', each character of the argument string will be appended to the list. Example usage:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument("--foo", action="extend", nargs="+", type=str)
>>> parser.parse_args(["--foo", "f1", "--foo", "f2", "f3", "f4"])
Namespace(foo=['f1', 'f2', 'f3', 'f4'])

Added in version 3.8.

'count' - 키워드 인자가 등장한 횟수를 계산합니다. 예를 들어, 상세도를 높이는 데 유용합니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--verbose', '-v', action='count', default=0)
>>> parser.parse_args(['-vvv'])
Namespace(verbose=3)

참고, 명시적으로 0으로 설정되지 않으면 default는 None이 됩니다.

'help' - 현재 파서의 모든 옵션에 대한 완전한 도움말 메시지를 출력하고 종료합니다. 기본적으로 help 액션은 자동으로 파서에 추가됩니다. 출력이 만들어지는 방법에 대한 자세한 내용은 ArgumentParser 를 보세요.

'version' - add_argument() 호출에서 version= 키워드 인자를 기대하고, 호출되면 버전 정보를 출력하고 종료합니다:

>>> import argparse
>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('--version', action='version', version='%(prog)s 2.0')
>>> parser.parse_args(['--version'])
PROG 2.0

Only actions that consume command-line arguments (e.g. 'store', 'append' or 'extend') can be used with positional arguments.

class argparse.BooleanOptionalAction

You may also specify an arbitrary action by passing an Action subclass or other object that implements the same interface. The BooleanOptionalAction is available in argparse and adds support for boolean actions such as --foo and --no-foo:

>>> import argparse
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action=argparse.BooleanOptionalAction)
>>> parser.parse_args(['--no-foo'])
Namespace(foo=False)

Added in version 3.9.

The recommended way to create a custom action is to extend Action, overriding the __call__() method and optionally the __init__() and format_usage() methods. You can also register custom actions using the register() method and reference them by their registered name.

사용자 정의 액션의 예:

>>> class FooAction(argparse.Action):
...     def __init__(self, option_strings, dest, nargs=None, **kwargs):
...         if nargs is not None:
...             raise ValueError("nargs not allowed")
...         super().__init__(option_strings, dest, **kwargs)
...     def __call__(self, parser, namespace, values, option_string=None):
...         print('%r %r %r' % (namespace, values, option_string))
...         setattr(namespace, self.dest, values)
...
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action=FooAction)
>>> parser.add_argument('bar', action=FooAction)
>>> args = parser.parse_args('1 --foo 2'.split())
Namespace(bar=None, foo=None) '1' None
Namespace(bar='1', foo=None) '2' '--foo'
>>> args
Namespace(bar='1', foo='2')

자세한 내용은 Action 을 참조하십시오.

nargs

ArgumentParser objects usually associate a single command-line argument with a single action to be taken. The nargs keyword argument associates a different number of command-line arguments with a single action. See also Specifying ambiguous arguments. The supported values are:

N (정수). 명령행에서 N 개의 인자를 함께 모아서 리스트에 넣습니다. 예를 들면:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', nargs=2)
>>> parser.add_argument('bar', nargs=1)
>>> parser.parse_args('c --foo a b'.split())
Namespace(bar=['c'], foo=['a', 'b'])

nargs=1 은 하나의 항목을 갖는 리스트를 생성합니다. 이는 항목 그대로 생성되는 기본값과 다릅니다.

'?'. 가능하다면 한 인자가 명령행에서 소비되고 단일 항목으로 생성됩니다. 명령행 인자가 없으면 default 의 값이 생성됩니다. 선택 인자의 경우 추가적인 경우가 있습니다 - 옵션 문자열은 있지만, 명령행 인자가 따라붙지 않는 경우입니다. 이 경우 const 의 값이 생성됩니다. 이것을 보여주기 위해 몇 가지 예를 듭니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', nargs='?', const='c', default='d')
>>> parser.add_argument('bar', nargs='?', default='d')
>>> parser.parse_args(['XX', '--foo', 'YY'])
Namespace(bar='XX', foo='YY')
>>> parser.parse_args(['XX', '--foo'])
Namespace(bar='XX', foo='c')
>>> parser.parse_args([])
Namespace(bar='d', foo='d')

nargs='?' 의 흔한 사용법 중 하나는 선택적 입출력 파일을 허용하는 것입니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('infile', nargs='?')
>>> parser.add_argument('outfile', nargs='?')
>>> parser.parse_args(['input.txt', 'output.txt'])
Namespace(infile='input.txt', outfile='output.txt')
>>> parser.parse_args(['input.txt'])
Namespace(infile='input.txt', outfile=None)
>>> parser.parse_args([])
Namespace(infile=None, outfile=None)

'*'. 모든 명령행 인자를 리스트로 수집합니다. 일반적으로 두 개 이상의 위치 인자에 대해 nargs='*' 를 사용하는 것은 별로 의미가 없지만, nargs='*' 를 갖는 여러 개의 선택 인자는 가능합니다. 예를 들면:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', nargs='*')
>>> parser.add_argument('--bar', nargs='*')
>>> parser.add_argument('baz', nargs='*')
>>> parser.parse_args('a b --foo x y --bar 1 2'.split())
Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])

'+'. '*' 와 같이, 존재하는 모든 명령행 인자를 리스트로 모읍니다. 또한, 적어도 하나의 명령행 인자가 제공되지 않으면 에러 메시지가 만들어집니다. 예를 들면:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('foo', nargs='+')
>>> parser.parse_args(['a', 'b'])
Namespace(foo=['a', 'b'])
>>> parser.parse_args([])
usage: PROG [-h] foo [foo ...]
PROG: error: the following arguments are required: foo

If the nargs keyword argument is not provided, the number of arguments consumed is determined by the action. Generally this means a single command-line argument will be consumed and a single item (not a list) will be produced. Actions that do not consume command-line arguments (e.g. 'store_const') set nargs=0.

const

add_argument() 의 const 인자는 명령행에서 읽지는 않지만 다양한 ArgumentParser 액션에 필요한 상숫값을 저장하는 데 사용됩니다. 가장 흔한 두 가지 용도는 다음과 같습니다:

When add_argument() is called with action='store_const' or action='append_const'. These actions add the const value to one of the attributes of the object returned by parse_args(). See the action description for examples. If const is not provided to add_argument(), it will receive a default value of None.

When add_argument() is called with option strings (like -f or --foo) and nargs='?'. This creates an optional argument that can be followed by zero or one command-line arguments. When parsing the command line, if the option string is encountered with no command-line argument following it, the value of const will be assumed to be None instead. See the nargs description for examples.

버전 3.11에서 변경: const=None by default, including when action='append_const' or action='store_const'.

default

모든 선택 인자와 일부 위치 인자는 명령행에서 생략될 수 있습니다. add_argument() 의 default 키워드 인자는, 기본값은 None 입니다, 명령행 인자가 없을 때 어떤 값을 사용해야 하는지를 지정합니다. 선택 인자의 경우, 옵션 문자열이 명령행에 없을 때 default 값이 사용됩니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', default=42)
>>> parser.parse_args(['--foo', '2'])
Namespace(foo='2')
>>> parser.parse_args([])
Namespace(foo=42)

If the target namespace already has an attribute set, the action default will not overwrite it:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', default=42)
>>> parser.parse_args([], namespace=argparse.Namespace(foo=101))
Namespace(foo=101)

default 값이 문자열이면, 파서는 마치 명령행 인자인 것처럼 파싱합니다. 특히, 파서는 Namespace 반환 값에 어트리뷰트를 설정하기 전에, 제공된 모든 type 변환 인자를 적용합니다. 그렇지 않은 경우, 파서는 값을 있는 그대로 사용합니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--length', default='10', type=int)
>>> parser.add_argument('--width', default=10.5, type=int)
>>> parser.parse_args()
Namespace(length=10, width=10.5)

nargs 가 ? 또는 * 인 위치 인자의 경우, 명령행 인자가 없을 때 default 값이 사용됩니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('foo', nargs='?', default=42)
>>> parser.parse_args(['a'])
Namespace(foo='a')
>>> parser.parse_args([])
Namespace(foo=42)

For required arguments, the default value is ignored. For example, this applies to positional arguments with nargs values other than ? or *, or optional arguments marked as required=True.

default=argparse.SUPPRESS 를 지정하면 명령행 인자가 없는 경우 어트리뷰트가 추가되지 않습니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', default=argparse.SUPPRESS)
>>> parser.parse_args([])
Namespace()
>>> parser.parse_args(['--foo', '1'])
Namespace(foo='1')

type

기본적으로, 파서는 명령행 인자를 간단한 문자열로 읽습니다. 그러나 꽤 자주 명령행 문자열은 float나 int와 같은 다른 형으로 해석되어야 합니다. add_argument() 의 type 키워드는 필요한 형 검사와 형 변환이 수행되도록 합니다.

type 키워드가 default 키워드와 함께 사용되면, 형 변환기는 기본값이 문자열일 때만 적용됩니다.

The argument to type can be a callable that accepts a single string or the name of a registered type (see register()) If the function raises ArgumentTypeError, TypeError, or ValueError, the exception is caught and a nicely formatted error message is displayed. Other exception types are not handled.

일반적인 내장형과 함수는 형 변환기로 사용될 수 있습니다:

import argparse
import pathlib

parser = argparse.ArgumentParser()
parser.add_argument('count', type=int)
parser.add_argument('distance', type=float)
parser.add_argument('street', type=ascii)
parser.add_argument('code_point', type=ord)
parser.add_argument('datapath', type=pathlib.Path)

사용자 정의 함수도 사용할 수 있습니다:

>>> def hyphenated(string):
...     return '-'.join([word[:4] for word in string.casefold().split()])
...
>>> parser = argparse.ArgumentParser()
>>> _ = parser.add_argument('short_title', type=hyphenated)
>>> parser.parse_args(['"The Tale of Two Cities"'])
Namespace(short_title='"the-tale-of-two-citi')

bool() 함수는 형 변환기로 권장되지 않습니다. 빈 문자열을 False로, 비어 있지 않은 문자열을 True로 변환하는 것뿐입니다. 이것은 일반적으로 원하는 것이 아닙니다.

일반적으로, type 키워드는 지원되는 세 가지 예외 중 하나만 발생할 수 있는 간단한 변환에만 사용해야 하는 편의 기능입니다. 더 흥미로운 에러 처리나 리소스 관리가 필요한 모든 작업은 인자가 구문 분석된 후에 수행되어야 합니다.

For example, JSON or YAML conversions have complex error cases that require better reporting than can be given by the type keyword. A JSONDecodeError would not be well formatted and a FileNotFoundError exception would not be handled at all.

Even FileType has its limitations for use with the type keyword. If one argument uses FileType and then a subsequent argument fails, an error is reported but the file is not automatically closed. In this case, it would be better to wait until after the parser has run and then use the with-statement to manage the files.

고정된 값 집합에 대해 단순히 확인하는 형 검사기의 경우, 대신 choices 키워드를 사용하는 것을 고려하십시오.

choices

Some command-line arguments should be selected from a restricted set of values. These can be handled by passing a sequence object as the choices keyword argument to add_argument(). When the command line is parsed, argument values will be checked, and an error message will be displayed if the argument was not one of the acceptable values:

>>> parser = argparse.ArgumentParser(prog='game.py')
>>> parser.add_argument('move', choices=['rock', 'paper', 'scissors'])
>>> parser.parse_args(['rock'])
Namespace(move='rock')
>>> parser.parse_args(['fire'])
usage: game.py [-h] {rock,paper,scissors}
game.py: error: argument move: invalid choice: 'fire' (choose from 'rock',
'paper', 'scissors')

Note that inclusion in the choices sequence is checked after any type conversions have been performed, so the type of the objects in the choices sequence should match the type specified.

Any sequence can be passed as the choices value, so list objects, tuple objects, and custom sequences are all supported.

enum.Enum은 사용법, 도움말 및 에러 메시지에서 나타나는 방식을 제어하기 어렵기 때문에 사용하지 않는 것이 좋습니다.

Formatted choices override the default metavar which is normally derived from dest. This is usually what you want because the user never sees the dest parameter. If this display isn’t desirable (perhaps because there are many choices), just specify an explicit metavar.

required

In general, the argparse module assumes that flags like -f and --bar indicate optional arguments, which can always be omitted at the command line. To make an option required, True can be specified for the required= keyword argument to add_argument():

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', required=True)
>>> parser.parse_args(['--foo', 'BAR'])
Namespace(foo='BAR')
>>> parser.parse_args([])
usage: [-h] --foo FOO
: error: the following arguments are required: --foo

예에서 보듯이, 옵션이 required 로 표시되면, parse_args() 는 그 옵션이 명령행에 없을 때 에러를 보고합니다.

참고

필수 옵션은 사용자가 옵션 이 선택적 일 것으로 기대하기 때문에 일반적으로 나쁜 형식으로 간주하므로 가능하면 피해야 합니다.

help

The help value is a string containing a brief description of the argument. When a user requests help (usually by using -h or --help at the command line), these help descriptions will be displayed with each argument.

help 문자열은 프로그램 이름이나 인자 default 와 같은 것들의 반복을 피하고자 다양한 포맷 지정자를 포함 할 수 있습니다. 사용할 수 있는 지정자는 프로그램 이름, %(prog)s 와 add_argument() 의 대부분의 키워드 인자, %(default)s, %(type)s 등을 포함합니다.:

>>> parser = argparse.ArgumentParser(prog='frobble')
>>> parser.add_argument('bar', nargs='?', type=int, default=42,
...                     help='the bar to %(prog)s (default: %(default)s)')
>>> parser.print_help()
usage: frobble [-h] [bar]

positional arguments:
 bar     the bar to frobble (default: 42)

options:
 -h, --help  show this help message and exit

도움말 문자열이 %-포매팅을 지원하기 때문에, 도움말 문자열에 리터럴 % 을 표시하려면, %% 로 이스케이프 처리해야 합니다.

argparse supports silencing the help entry for certain options, by setting the help value to argparse.SUPPRESS:

>>> parser = argparse.ArgumentParser(prog='frobble')
>>> parser.add_argument('--foo', help=argparse.SUPPRESS)
>>> parser.print_help()
usage: frobble [-h]

options:
  -h, --help  show this help message and exit

metavar

When ArgumentParser generates help messages, it needs some way to refer to each expected argument. By default, ArgumentParser objects use the dest value as the “name” of each object. By default, for positional argument actions, the dest value is used directly, and for optional argument actions, the dest value is uppercased. So, a single positional argument with dest='bar' will be referred to as bar. A single optional argument --foo that should be followed by a single command-line argument will be referred to as FOO. An example:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo')
>>> parser.add_argument('bar')
>>> parser.parse_args('X --foo Y'.split())
Namespace(bar='X', foo='Y')
>>> parser.print_help()
usage:  [-h] [--foo FOO] bar

positional arguments:
 bar

options:
 -h, --help  show this help message and exit
 --foo FOO

다른 이름은 metavar 로 지정할 수 있습니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', metavar='YYY')
>>> parser.add_argument('bar', metavar='XXX')
>>> parser.parse_args('X --foo Y'.split())
Namespace(bar='X', foo='Y')
>>> parser.print_help()
usage:  [-h] [--foo YYY] XXX

positional arguments:
 XXX

options:
 -h, --help  show this help message and exit
 --foo YYY

metavar 는 표시되는 이름 만 변경합니다 - parse_args() 객체의 어트리뷰트 이름은 여전히 dest 값에 의해 결정됩니다.

nargs 값이 다르면 metavar 가 여러 번 사용될 수 있습니다. metavar 에 튜플을 제공하면 인자마다 다른 디스플레이가 지정됩니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-x', nargs=2)
>>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))
>>> parser.print_help()
usage: PROG [-h] [-x X X] [--foo bar baz]

options:
 -h, --help     show this help message and exit
 -x X X
 --foo bar baz

dest

대부분 ArgumentParser 액션은 parse_args() 에 의해 반환된 객체의 어트리뷰트로 어떤 값을 추가합니다. 이 어트리뷰트의 이름은 add_argument() 의 dest 키워드 인자에 의해 결정됩니다. 위치 인자 액션의 경우, dest 는 일반적으로 add_argument() 에 첫 번째 인자로 제공됩니다.:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('bar')
>>> parser.parse_args(['XXX'])
Namespace(bar='XXX')

선택 인자 액션의 경우, dest 의 값은 보통 옵션 문자열에서 유추됩니다. ArgumentParser 는 첫 번째 긴 옵션 문자열을 취하고 앞의 -- 문자열을 제거하여 dest 의 값을 만듭니다. 긴 옵션 문자열이 제공되지 않았다면 dest 는 첫 번째 짧은 옵션 문자열에서 앞의 - 문자를 제거하여 만듭니다. 문자열이 항상 유효한 어트리뷰트 이름이 되도록 만들기 위해 중간에 나오는 - 문자는 _ 문자로 변환됩니다. 아래 예제는 이 동작을 보여줍니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('-f', '--foo-bar', '--foo')
>>> parser.add_argument('-x', '-y')
>>> parser.parse_args('-f 1 -x 2'.split())
Namespace(foo_bar='1', x='2')
>>> parser.parse_args('--foo 1 -y 2'.split())
Namespace(foo_bar='1', x='2')

dest 는 사용자 정의 어트리뷰트 이름을 지정할 수 있게 합니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', dest='bar')
>>> parser.parse_args('--foo XXX'.split())
Namespace(bar='XXX')

deprecated

During a project’s lifetime, some arguments may need to be removed from the command line. Before removing them, you should inform your users that the arguments are deprecated and will be removed. The deprecated keyword argument of add_argument(), which defaults to False, specifies if the argument is deprecated and will be removed in the future. For arguments, if deprecated is True, then a warning will be printed to sys.stderr when the argument is used:

>>> import argparse
>>> parser = argparse.ArgumentParser(prog='snake.py')
>>> parser.add_argument('--legs', default=0, type=int, deprecated=True)
>>> parser.parse_args([])
Namespace(legs=0)
>>> parser.parse_args(['--legs', '4'])
snake.py: warning: option '--legs' is deprecated
Namespace(legs=4)

Added in version 3.13.

Action 클래스

Action classes implement the Action API, a callable which returns a callable which processes arguments from the command-line. Any object which follows this API may be passed as the action parameter to add_argument().

class argparse.Action(option_strings, dest, nargs=None, const=None, default=None, type=None, choices=None, required=False, help=None, metavar=None)

Action objects are used by an ArgumentParser to represent the information needed to parse a single argument from one or more strings from the command line. The Action class must accept the two positional arguments plus any keyword arguments passed to ArgumentParser.add_argument() except for the action itself.

Instances of Action (or return value of any callable to the action parameter) should have attributes dest, option_strings, default, type, required, help, etc. defined. The easiest way to ensure these attributes are defined is to call Action.__init__().

__call__(parser, namespace, values, option_string=None)

Action instances should be callable, so subclasses must override the __call__() method, which should accept four parameters:

parser - The ArgumentParser object which contains this action.

namespace - The Namespace object that will be returned by parse_args(). Most actions add an attribute to this object using setattr().

values - The associated command-line arguments, with any type conversions applied. Type conversions are specified with the type keyword argument to add_argument().

option_string - The option string that was used to invoke this action. The option_string argument is optional, and will be absent if the action is associated with a positional argument.

The __call__() method may perform arbitrary actions, but will typically set attributes on the namespace based on dest and values.

format_usage()

Action subclasses can define a format_usage() method that takes no argument and return a string which will be used when printing the usage of the program. If such method is not provided, a sensible default will be used.

parse_args() 메서드

ArgumentParser.parse_args(args=None, namespace=None)

인자 문자열을 객체로 변환하고 namespace의 어트리뷰트로 설정합니다. 값들이 설정된 namespace를 돌려줍니다.

Previous calls to add_argument() determine exactly what objects are created and how they are assigned. See the documentation for add_argument() for details.

args - 구문 분석할 문자열 리스트. 기본값은 sys.argv 에서 취합니다.

namespace - 어트리뷰트가 대입될 객체. 기본값은 새로 만들어지는 빈 Namespace 객체입니다.

옵션값 문법

parse_args() 메서드는 (취할 것이 있다면) 옵션의 값을 지정하는 몇 가지 방법을 지원합니다. 가장 단순한 경우, 옵션과 그 값은 두 개의 독립적인 인자로 전달됩니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-x')
>>> parser.add_argument('--foo')
>>> parser.parse_args(['-x', 'X'])
Namespace(foo=None, x='X')
>>> parser.parse_args(['--foo', 'FOO'])
Namespace(foo='FOO', x=None)

긴 옵션(단일 문자보다 긴 이름을 가진 옵션)의 경우, 옵션과 값을 = 로 구분하여 단일 명령행 인자로 전달할 수도 있습니다:

>>> parser.parse_args(['--foo=FOO'])
Namespace(foo='FOO', x=None)

짧은 옵션(한 문자 길이의 옵션)의 경우, 옵션과 해당 값을 이어붙일 수 있습니다:

>>> parser.parse_args(['-xX'])
Namespace(foo=None, x='X')

여러 개의 짧은 옵션은 마지막 옵션만 값을 요구하는 한 (또는 그들 중 아무것도 값을 요구하지 않거나), 하나의 - 접두어를 사용하여 함께 결합 할 수 있습니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-x', action='store_true')
>>> parser.add_argument('-y', action='store_true')
>>> parser.add_argument('-z')
>>> parser.parse_args(['-xyzZ'])
Namespace(x=True, y=True, z='Z')

잘못된 인자

명령행을 파싱할 때, parse_args() 는 모호한 옵션, 유효하지 않은 형, 유효하지 않은 옵션, 잘못된 위치 인자의 수 등을 포함한 다양한 에러를 검사합니다. 이런 에러가 발생하면, 사용 메시지와 함께 에러를 인쇄합니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('--foo', type=int)
>>> parser.add_argument('bar', nargs='?')

>>> # invalid type
>>> parser.parse_args(['--foo', 'spam'])
usage: PROG [-h] [--foo FOO] [bar]
PROG: error: argument --foo: invalid int value: 'spam'

>>> # invalid option
>>> parser.parse_args(['--bar'])
usage: PROG [-h] [--foo FOO] [bar]
PROG: error: no such option: --bar

>>> # wrong number of arguments
>>> parser.parse_args(['spam', 'badger'])
usage: PROG [-h] [--foo FOO] [bar]
PROG: error: extra arguments found: badger

- 를 포함하는 인자들

parse_args() 메서드는 사용자가 분명히 실수했을 때마다 에러를 주려고 하지만, 어떤 상황은 본질에서 모호합니다. 예를 들어, 명령행 인자 -1 은 옵션을 지정하려는 시도이거나 위치 인자를 제공하려는 시도일 수 있습니다. parse_args() 메서드는 이럴 때 신중합니다: 위치 인자는 음수처럼 보이고 파서에 음수처럼 보이는 옵션이 없을 때만 - 로 시작할 수 있습니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-x')
>>> parser.add_argument('foo', nargs='?')

>>> # no negative number options, so -1 is a positional argument
>>> parser.parse_args(['-x', '-1'])
Namespace(foo=None, x='-1')

>>> # no negative number options, so -1 and -5 are positional arguments
>>> parser.parse_args(['-x', '-1', '-5'])
Namespace(foo='-5', x='-1')

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-1', dest='one')
>>> parser.add_argument('foo', nargs='?')

>>> # negative number options present, so -1 is an option
>>> parser.parse_args(['-1', 'X'])
Namespace(foo=None, one='X')

>>> # negative number options present, so -2 is an option
>>> parser.parse_args(['-2'])
usage: PROG [-h] [-1 ONE] [foo]
PROG: error: no such option: -2

>>> # negative number options present, so both -1s are options
>>> parser.parse_args(['-1', '-1'])
usage: PROG [-h] [-1 ONE] [foo]
PROG: error: argument -1: expected one argument

- 로 시작해야 하고, 음수처럼 보이지 않는 위치 인자가 있는 경우, parse_args() 에 다음과 같은 의사 인자 '--' 를 삽입 할 수 있습니다. 그 이후의 모든 것은 위치 인자입니다:

>>> parser.parse_args(['--', '-f'])
Namespace(foo='-f', one=None)

See also the argparse howto on ambiguous arguments for more details.

인자 약어 (접두사 일치)

parse_args() 메서드는 기본적으로 약어가 모호하지 않으면 (접두사가 오직 하나의 옵션과 일치합니다) 긴 옵션을 접두사로 축약 할 수 있도록 합니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-bacon')
>>> parser.add_argument('-badger')
>>> parser.parse_args('-bac MMM'.split())
Namespace(bacon='MMM', badger=None)
>>> parser.parse_args('-bad WOOD'.split())
Namespace(bacon=None, badger='WOOD')
>>> parser.parse_args('-ba BA'.split())
usage: PROG [-h] [-bacon BACON] [-badger BADGER]
PROG: error: ambiguous option: -ba could match -badger, -bacon

둘 이상의 옵션과 일치하는 인자는 에러를 일으킵니다. 이 기능은 allow_abbrev를 False 로 설정함으로써 비활성화시킬 수 있습니다.

sys.argv 너머

Sometimes it may be useful to have an ArgumentParser parse arguments other than those of sys.argv. This can be accomplished by passing a list of strings to parse_args(). This is useful for testing at the interactive prompt:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument(
...     'integers', metavar='int', type=int, choices=range(10),
...     nargs='+', help='an integer in the range 0..9')
>>> parser.add_argument(
...     '--sum', dest='accumulate', action='store_const', const=sum,
...     default=max, help='sum the integers (default: find the max)')
>>> parser.parse_args(['1', '2', '3', '4'])
Namespace(accumulate=<built-in function max>, integers=[1, 2, 3, 4])
>>> parser.parse_args(['1', '2', '3', '4', '--sum'])
Namespace(accumulate=<built-in function sum>, integers=[1, 2, 3, 4])

Namespace 객체

class argparse.Namespace

parse_args() 가 어트리뷰트를 저장하고 반환할 객체를 만드는 데 기본적으로 사용하는 간단한 클래스.

이 클래스는 의도적으로 단순한데, 단지 가독성 있는 문자열 표현을 갖는 object 의 서브 클래스입니다. 어트리뷰트를 딕셔너리처럼 보기 원한다면, 표준 파이썬 관용구를 사용할 수 있습니다, vars():

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo')
>>> args = parser.parse_args(['--foo', 'BAR'])
>>> vars(args)
{'foo': 'BAR'}

ArgumentParser 가 새 Namespace 객체가 아니라 이미 존재하는 객체에 어트리뷰트를 대입하는 것이 유용 할 수 있습니다. namespace= 키워드 인자를 지정하면 됩니다:

>>> class C:
...     pass
...
>>> c = C()
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo')
>>> parser.parse_args(args=['--foo', 'BAR'], namespace=c)
>>> c.foo
'BAR'

기타 유틸리티

부속 명령

ArgumentParser.add_subparsers(*[, title][, description][, prog][, parser_class][, action][, dest][, required][, help][, metavar])

Many programs split up their functionality into a number of subcommands, for example, the svn program can invoke subcommands like svn checkout, svn update, and svn commit. Splitting up functionality this way can be a particularly good idea when a program performs several different functions which require different kinds of command-line arguments. ArgumentParser supports the creation of such subcommands with the add_subparsers() method. The add_subparsers() method is normally called with no arguments and returns a special action object. This object has a single method, add_parser(), which takes a command name and any ArgumentParser constructor arguments, and returns an ArgumentParser object that can be modified as usual.

매개 변수 설명:

title - title for the sub-parser group in help output; by default “subcommands” if description is provided, otherwise uses title for positional arguments

description - description for the sub-parser group in help output, by default None

prog - usage information that will be displayed with sub-command help, by default the name of the program and any positional arguments before the subparser argument

parser_class - class which will be used to create sub-parser instances, by default the class of the current parser (e.g. ArgumentParser)

action - 이 인자를 명령행에서 만날 때 수행 할 액션의 기본형

dest - 부속 명령 이름을 저장하는 어트리뷰트의 이름. 기본적으로 None 이며 값은 저장되지 않습니다.

required - 부속 명령이 꼭 제공되어야 하는지 아닌지, 기본값은 False (3.7에서 추가)

help - 도움말 출력의 부속 파서 그룹 도움말, 기본적으로 None

metavar - string presenting available subcommands in help; by default it is None and presents subcommands in form {cmd1, cmd2, ..}

몇 가지 사용 예:

>>> # create the top-level parser
>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('--foo', action='store_true', help='foo help')
>>> subparsers = parser.add_subparsers(help='subcommand help')
>>>
>>> # create the parser for the "a" command
>>> parser_a = subparsers.add_parser('a', help='a help')
>>> parser_a.add_argument('bar', type=int, help='bar help')
>>>
>>> # create the parser for the "b" command
>>> parser_b = subparsers.add_parser('b', help='b help')
>>> parser_b.add_argument('--baz', choices=('X', 'Y', 'Z'), help='baz help')
>>>
>>> # parse some argument lists
>>> parser.parse_args(['a', '12'])
Namespace(bar=12, foo=False)
>>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
Namespace(baz='Z', foo=True)

parse_args() 에 의해 반환된 객체는 주 파서와 명령행에 의해 선택된 부속 파서(다른 부속 파서는 아님)의 어트리뷰트만을 포함한다는 것에 주의하십시오. 그래서 위의 예에서, a 명령이 지정되면 foo 와 bar 어트리뷰트 만 존재하고, b 명령이 지정되면 foo 와 baz 어트리뷰트만 존재합니다.

Similarly, when a help message is requested from a subparser, only the help for that particular parser will be printed. The help message will not include parent parser or sibling parser messages. (A help message for each subparser command, however, can be given by supplying the help= argument to add_parser() as above.)

>>> parser.parse_args(['--help'])
usage: PROG [-h] [--foo] {a,b} ...

positional arguments:
  {a,b}   subcommand help
    a     a help
    b     b help

options:
  -h, --help  show this help message and exit
  --foo   foo help

>>> parser.parse_args(['a', '--help'])
usage: PROG a [-h] bar

positional arguments:
  bar     bar help

options:
  -h, --help  show this help message and exit

>>> parser.parse_args(['b', '--help'])
usage: PROG b [-h] [--baz {X,Y,Z}]

options:
  -h, --help     show this help message and exit
  --baz {X,Y,Z}  baz help

add_subparsers() 메서드는 또한 title 과 description 키워드 인자를 지원합니다. 둘 중 하나가 있으면 부속 파서의 명령이 도움말 출력에서 자체 그룹으로 나타납니다. 예를 들면:

>>> parser = argparse.ArgumentParser()
>>> subparsers = parser.add_subparsers(title='subcommands',
...                                    description='valid subcommands',
...                                    help='additional help')
>>> subparsers.add_parser('foo')
>>> subparsers.add_parser('bar')
>>> parser.parse_args(['-h'])
usage:  [-h] {foo,bar} ...

options:
  -h, --help  show this help message and exit

subcommands:
  valid subcommands

  {foo,bar}   additional help

Furthermore, add_parser() supports an additional aliases argument, which allows multiple strings to refer to the same subparser. This example, like svn, aliases co as a shorthand for checkout:

>>> parser = argparse.ArgumentParser()
>>> subparsers = parser.add_subparsers()
>>> checkout = subparsers.add_parser('checkout', aliases=['co'])
>>> checkout.add_argument('foo')
>>> parser.parse_args(['co', 'bar'])
Namespace(foo='bar')

add_parser() supports also an additional deprecated argument, which allows to deprecate the subparser.

>>> import argparse
>>> parser = argparse.ArgumentParser(prog='chicken.py')
>>> subparsers = parser.add_subparsers()
>>> run = subparsers.add_parser('run')
>>> fly = subparsers.add_parser('fly', deprecated=True)
>>> parser.parse_args(['fly'])
chicken.py: warning: command 'fly' is deprecated
Namespace()

Added in version 3.13.

One particularly effective way of handling subcommands is to combine the use of the add_subparsers() method with calls to set_defaults() so that each subparser knows which Python function it should execute. For example:

>>> # subcommand functions
>>> def foo(args):
...     print(args.x * args.y)
...
>>> def bar(args):
...     print('((%s))' % args.z)
...
>>> # create the top-level parser
>>> parser = argparse.ArgumentParser()
>>> subparsers = parser.add_subparsers(required=True)
>>>
>>> # create the parser for the "foo" command
>>> parser_foo = subparsers.add_parser('foo')
>>> parser_foo.add_argument('-x', type=int, default=1)
>>> parser_foo.add_argument('y', type=float)
>>> parser_foo.set_defaults(func=foo)
>>>
>>> # create the parser for the "bar" command
>>> parser_bar = subparsers.add_parser('bar')
>>> parser_bar.add_argument('z')
>>> parser_bar.set_defaults(func=bar)
>>>
>>> # parse the args and call whatever function was selected
>>> args = parser.parse_args('foo 1 -x 2'.split())
>>> args.func(args)
2.0
>>>
>>> # parse the args and call whatever function was selected
>>> args = parser.parse_args('bar XYZYX'.split())
>>> args.func(args)
((XYZYX))

이렇게 하면 parse_args() 가 파싱이 완료된 후 적절한 함수를 호출하게 할 수 있습니다. 이처럼 액션과 함수를 연결하는 것이, 일반적으로 각 부속 파서가 서로 다른 액션을 처리하도록 하는 가장 쉬운 방법입니다. 그러나 호출된 부속 파서의 이름을 확인해야 하는 경우 add_subparsers() 호출에 dest 키워드 인자를 제공합니다:

>>> parser = argparse.ArgumentParser()
>>> subparsers = parser.add_subparsers(dest='subparser_name')
>>> subparser1 = subparsers.add_parser('1')
>>> subparser1.add_argument('-x')
>>> subparser2 = subparsers.add_parser('2')
>>> subparser2.add_argument('y')
>>> parser.parse_args(['2', 'frobble'])
Namespace(subparser_name='2', y='frobble')

버전 3.7에서 변경: New required keyword-only parameter.

버전 3.14에서 변경: Subparser’s prog is no longer affected by a custom usage message in the main parser.

FileType 객체

class argparse.FileType(mode='r', bufsize=-1, encoding=None, errors=None)

FileType 팩토리는 ArgumentParser.add_argument() 의 type 인자로 전달될 수 있는 객체를 만듭니다. type으로 FileType 객체를 사용하는 인자는 명령행 인자를 요청된 모드, 버퍼 크기, 인코딩 및 오류 처리의 파일로 엽니다 (자세한 내용은 open() 함수를 참조하세요):

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--raw', type=argparse.FileType('wb', 0))
>>> parser.add_argument('out', type=argparse.FileType('w', encoding='UTF-8'))
>>> parser.parse_args(['--raw', 'raw.dat', 'file.txt'])
Namespace(out=<_io.TextIOWrapper name='file.txt' mode='w' encoding='UTF-8'>, raw=<_io.FileIO name='raw.dat' mode='wb'>)

FileType objects understand the pseudo-argument '-' and automatically convert this into sys.stdin for readable FileType objects and sys.stdout for writable FileType objects:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('infile', type=argparse.FileType('r'))
>>> parser.parse_args(['-'])
Namespace(infile=<_io.TextIOWrapper name='<stdin>' encoding='UTF-8'>)

참고

If one argument uses FileType and then a subsequent argument fails, an error is reported but the file is not automatically closed. This can also clobber the output files. In this case, it would be better to wait until after the parser has run and then use the with-statement to manage the files.

버전 3.4에서 변경: Added the encodings and errors parameters.

버전 3.14부터 폐지됨.

인자 그룹

ArgumentParser.add_argument_group(title=None, description=None, *[, argument_default][, conflict_handler])

By default, ArgumentParser groups command-line arguments into “positional arguments” and “options” when displaying help messages. When there is a better conceptual grouping of arguments than this default one, appropriate groups can be created using the add_argument_group() method:

>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
>>> group = parser.add_argument_group('group')
>>> group.add_argument('--foo', help='foo help')
>>> group.add_argument('bar', help='bar help')
>>> parser.print_help()
usage: PROG [--foo FOO] bar

group:
  bar    bar help
  --foo FOO  foo help

The add_argument_group() method returns an argument group object which has an add_argument() method just like a regular ArgumentParser. When an argument is added to the group, the parser treats it just like a normal argument, but displays the argument in a separate group for help messages. The add_argument_group() method accepts title and description arguments which can be used to customize this display:

>>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
>>> group1 = parser.add_argument_group('group1', 'group1 description')
>>> group1.add_argument('foo', help='foo help')
>>> group2 = parser.add_argument_group('group2', 'group2 description')
>>> group2.add_argument('--bar', help='bar help')
>>> parser.print_help()
usage: PROG [--bar BAR] foo

group1:
  group1 description

  foo    foo help

group2:
  group2 description

  --bar BAR  bar help

The optional, keyword-only parameters argument_default and conflict_handler allow for finer-grained control of the behavior of the argument group. These parameters have the same meaning as in the ArgumentParser constructor, but apply specifically to the argument group rather than the entire parser.

사용자 정의 그룹에 없는 인자는 일반적인 “positional arguments” 및 “optional arguments” 섹션으로 들어갑니다.

Deprecated since version 3.11, removed in version 3.14: Calling add_argument_group() on an argument group now raises an exception. This nesting was never supported, often failed to work correctly, and was unintentionally exposed through inheritance.

버전 3.14부터 폐지됨: Passing prefix_chars to add_argument_group() is now deprecated.

상호 배제

ArgumentParser.add_mutually_exclusive_group(required=False)

Create a mutually exclusive group. argparse will make sure that only one of the arguments in the mutually exclusive group was present on the command line:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> group = parser.add_mutually_exclusive_group()
>>> group.add_argument('--foo', action='store_true')
>>> group.add_argument('--bar', action='store_false')
>>> parser.parse_args(['--foo'])
Namespace(bar=True, foo=True)
>>> parser.parse_args(['--bar'])
Namespace(bar=False, foo=False)
>>> parser.parse_args(['--foo', '--bar'])
usage: PROG [-h] [--foo | --bar]
PROG: error: argument --bar: not allowed with argument --foo

add_mutually_exclusive_group() 메서드는 상호 배타적 인자 중 적어도 하나가 필요하다는 것을 나타내기 위한 required 인자도 받아들입니다:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> group = parser.add_mutually_exclusive_group(required=True)
>>> group.add_argument('--foo', action='store_true')
>>> group.add_argument('--bar', action='store_false')
>>> parser.parse_args([])
usage: PROG [-h] (--foo | --bar)
PROG: error: one of the arguments --foo --bar is required

Note that currently mutually exclusive argument groups do not support the title and description arguments of add_argument_group(). However, a mutually exclusive group can be added to an argument group that has a title and description. For example:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> group = parser.add_argument_group('Group title', 'Group description')
>>> exclusive_group = group.add_mutually_exclusive_group(required=True)
>>> exclusive_group.add_argument('--foo', help='foo help')
>>> exclusive_group.add_argument('--bar', help='bar help')
>>> parser.print_help()
usage: PROG [-h] (--foo FOO | --bar BAR)

options:
  -h, --help  show this help message and exit

Group title:
  Group description

  --foo FOO   foo help
  --bar BAR   bar help

Deprecated since version 3.11, removed in version 3.14: Calling add_argument_group() or add_mutually_exclusive_group() on a mutually exclusive group now raises an exception. This nesting was never supported, often failed to work correctly, and was unintentionally exposed through inheritance.

파서 기본값

ArgumentParser.set_defaults(**kwargs)

대부분은, parse_args() 에 의해 반환된 객체의 어트리뷰트는 명령행 인자와 인자 액션을 검사하여 완전히 결정됩니다. set_defaults() 는 명령행을 검사하지 않고 결정되는 몇 가지 추가적인 어트리뷰트를 추가할 수 있도록 합니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('foo', type=int)
>>> parser.set_defaults(bar=42, baz='badger')
>>> parser.parse_args(['736'])
Namespace(bar=42, baz='badger', foo=736)

파서 수준의 기본값은 항상 인자 수준의 기본값보다 우선합니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', default='bar')
>>> parser.set_defaults(foo='spam')
>>> parser.parse_args([])
Namespace(foo='spam')

파서 수준의 기본값은 여러 파서로 작업 할 때 특히 유용 할 수 있습니다. 이 유형의 예제는 add_subparsers() 메서드를 참조하십시오.

ArgumentParser.get_default(dest)

add_argument() 또는 set_defaults() 에 의해 설정된 이름 공간 어트리뷰트의 기본값을 가져옵니다:

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', default='badger')
>>> parser.get_default('foo')
'badger'

도움말 인쇄

대부분의 일반적인 응용 프로그램에서 parse_args() 가 사용법이나 오류 메시지를 포매팅하고 인쇄하는 것을 담당합니다. 그러나 여러 가지 포매팅 방법이 제공됩니다:

ArgumentParser.print_usage(file=None)

ArgumentParser 가 어떻게 명령행에서 호출되어야 하는지에 대한 간단한 설명을 인쇄합니다. file 이 None 이면, sys.stdout 이 가정됩니다.

ArgumentParser.print_help(file=None)

프로그램 사용법과 ArgumentParser 에 등록된 인자에 대한 정보를 포함하는 도움말 메시지를 출력합니다. file 이 None 이면, sys.stdout 이 가정됩니다.

인쇄하는 대신 단순히 문자열을 반환하는, 이러한 메서드의 변형도 있습니다:

ArgumentParser.format_usage()

ArgumentParser 가 어떻게 명령행에서 호출되어야 하는지에 대한 간단한 설명을 담은 문자열을 반환합니다.

ArgumentParser.format_help()

프로그램 사용법과 ArgumentParser 에 등록된 인자에 대한 정보를 포함하는 도움말 메시지를 담은 문자열을 반환합니다.

부분 파싱

ArgumentParser.parse_known_args(args=None, namespace=None)

때에 따라 스크립트는 명령행 인자 중 일부만 파싱하고 나머지 인자를 다른 스크립트 나 프로그램에 전달할 수 있습니다. 이 경우 parse_known_args() 메서드가 유용 할 수 있습니다. parse_args() 와 매우 유사하게 작동하는데, 여분의 인자가 있을 때 에러를 발생시키지 않는 점이 다릅니다. 대신, 채워진 이름 공간과 여분의 인자 문자열 리스트를 포함하는 두 항목 튜플을 반환합니다.

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', action='store_true')
>>> parser.add_argument('bar')
>>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])
(Namespace(bar='BAR', foo=True), ['--badger', 'spam'])

경고

Prefix matching rules apply to parse_known_args(). The parser may consume an option even if it’s just a prefix of one of its known options, instead of leaving it in the remaining arguments list.

파일 파싱 사용자 정의

ArgumentParser.convert_arg_line_to_args(arg_line)

파일에서 읽은 인자는 (ArgumentParser 생성자의 fromfile_prefix_chars 키워드 인자를 참조하세요) 한 줄에 하나의 인자로 읽습니다. 이 동작을 변경하려면 convert_arg_line_to_args() 를 재정의합니다.

이 메서드는 하나의 인자 arg_line 를 받아들이는데, 인자 파일에서 읽어 들인 문자열입니다. 이 문자열에서 파싱된 인자 리스트를 반환합니다. 메서드는 인자 파일에서 읽어 들이는 대로 한 줄에 한 번씩 순서대로 호출됩니다.

이 메서드의 재정의하는 유용한 경우는 스페이스로 분리된 각 단어를 인자로 처리하는 것입니다. 다음 예제는 이렇게 하는 방법을 보여줍니다:

class MyArgumentParser(argparse.ArgumentParser):
    def convert_arg_line_to_args(self, arg_line):
        return arg_line.split()

종료 메서드

ArgumentParser.exit(status=0, message=None)

This method terminates the program, exiting with the specified status and, if given, it prints a message to sys.stderr before that. The user can override this method to handle these steps differently:

class ErrorCatchingArgumentParser(argparse.ArgumentParser):
    def exit(self, status=0, message=None):
        if status:
            raise Exception(f'Exiting because of an error: {message}')
        exit(status)

ArgumentParser.error(message)

This method prints a usage message, including the message, to sys.stderr and terminates the program with a status code of 2.

혼합 파싱

ArgumentParser.parse_intermixed_args(args=None, namespace=None)

ArgumentParser.parse_known_intermixed_args(args=None, namespace=None)

많은 유닉스 명령은 사용자가 선택 인자와 위치 인자를 섞을 수 있도록 합니다. parse_intermixed_args() 와 parse_known_intermixed_args() 메서드는 이런 파싱 스타일을 지원합니다.

These parsers do not support all the argparse features, and will raise exceptions if unsupported features are used. In particular, subparsers, and mutually exclusive groups that include both optionals and positionals are not supported.

다음 예제는 parse_known_args() 와 parse_intermixed_args() 의 차이점을 보여줍니다: 전자는 여분의 인자로 ['2', '3'] 을 반환하는 반면, 후자는 모든 위치 인자를 rest 로 모읍니다.

>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo')
>>> parser.add_argument('cmd')
>>> parser.add_argument('rest', nargs='*', type=int)
>>> parser.parse_known_args('doit 1 --foo bar 2 3'.split())
(Namespace(cmd='doit', foo='bar', rest=[1]), ['2', '3'])
>>> parser.parse_intermixed_args('doit 1 --foo bar 2 3'.split())
Namespace(cmd='doit', foo='bar', rest=[1, 2, 3])

parse_known_intermixed_args() 는 채워진 이름 공간과 잔여 인자 문자열의 리스트를 포함하는 두 항목 튜플을 반환합니다. parse_intermixed_args() 는 파싱되지 않은 인자 문자열이 남아 있으면 에러를 발생시킵니다.

Added in version 3.7.

Registering custom types or actions

ArgumentParser.register(registry_name, value, object)

Sometimes it’s desirable to use a custom string in error messages to provide more user-friendly output. In these cases, register() can be used to register custom actions or types with a parser and allow you to reference the type by their registered name instead of their callable name.

The register() method accepts three arguments - a registry_name, specifying the internal registry where the object will be stored (e.g., action, type), value, which is the key under which the object will be registered, and object, the callable to be registered.

The following example shows how to register a custom type with a parser:

>>> import argparse
>>> parser = argparse.ArgumentParser()
>>> parser.register('type', 'hexadecimal integer', lambda s: int(s, 16))
>>> parser.add_argument('--foo', type='hexadecimal integer')
_StoreAction(option_strings=['--foo'], dest='foo', nargs=None, const=None, default=None, type='hexadecimal integer', choices=None, required=False, help=None, metavar=None, deprecated=False)
>>> parser.parse_args(['--foo', '0xFA'])
Namespace(foo=250)
>>> parser.parse_args(['--foo', '1.2'])
usage: PROG [-h] [--foo FOO]
PROG: error: argument --foo: invalid 'hexadecimal integer' value: '1.2'

Exceptions

exception argparse.ArgumentError

An error from creating or using an argument (optional or positional).

The string value of this exception is the message, augmented with information about the argument that caused it.

exception argparse.ArgumentTypeError

Raised when something goes wrong converting a command line string to a type.

Guides and Tutorials

Argparse 자습서

Upgrading optparse code

Argparse 자습서

저자:

Tshepang Mbambo

이 자습서는 파이썬 표준 라이브러리에서 권장하는 명령행 파싱 모듈인 argparse 에 대한 소개입니다.

참고

There are two other modules that fulfill the same task, namely getopt (an equivalent for getopt() from the C language) and the deprecated optparse. Note also that argparse is based on optparse, and therefore very similar in terms of usage.

개념

ls 명령을 사용하여 이 입문서에서 다룰 기능들을 살펴봅시다:

$ ls
cpython  devguide  prog.py  pypy  rm-unused-function.patch
$ ls pypy
ctypes_configure  demo  dotviewer  include  lib_pypy  lib-python ...
$ ls -l
total 20
drwxr-xr-x 19 wena wena 4096 Feb 18 18:51 cpython
drwxr-xr-x  4 wena wena 4096 Feb  8 12:04 devguide
-rwxr-xr-x  1 wena wena  535 Feb 19 00:05 prog.py
drwxr-xr-x 14 wena wena 4096 Feb  7 00:59 pypy
-rw-r--r--  1 wena wena  741 Feb 18 01:01 rm-unused-function.patch
$ ls --help
Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
...

네 가지 명령에서 배울 수 있는 몇 가지 개념들입니다:

ls 명령은 옵션 없이 실행될 때도 유용합니다. 기본적으로 현재 디렉터리의 내용을 표시합니다.

기본적으로 제공하는 것 이상으로 원한다면, 조금 더 말합니다. 이 경우에는 다른 디렉터리인 pypy 를 표시하기를 원합니다. 우리가 한 것은 위치 인자라고 알려진 것을 지정하는 것입니다. 프로그램이 명령행에 표시되는 위치를 기준으로 값을 어떻게 처리해야 하는지를 알아야 하므로 이런 이름이 사용됩니다. 이 개념은 cp 와 같은 명령에 더 적절합니다. 가장 기본적인 사용법은 cp SRC DEST 입니다. 첫 번째 위치는 복사하고자 하는 것 이고 두 번째 위치는 사본을 저장할 곳 입니다.

자, 프로그램의 행동을 바꾸고 싶다고 합시다. 이 예에서는 파일 이름만 표시하는 대신 각 파일에 대한 정보를 더 많이 표시합니다. 이 경우 -l 은 옵션 인자로 알려져 있습니다.

이것이 도움말 텍스트입니다. 이전에 사용해보지 않은 프로그램을 접했을 때 도움말 텍스트를 읽는 것만으로 작동하는 방식을 이해할 수 있다는 점에서 매우 유용합니다.

기본

(거의) 아무것도 하지 않는 아주 간단한 예제로 시작합시다:

import argparse
parser = argparse.ArgumentParser()
parser.parse_args()

다음은 코드를 실행한 결과입니다:

$ python prog.py
$ python prog.py --help
usage: prog.py [-h]

options:
  -h, --help  show this help message and exit
$ python prog.py --verbose
usage: prog.py [-h]
prog.py: error: unrecognized arguments: --verbose
$ python prog.py foo
usage: prog.py [-h]
prog.py: error: unrecognized arguments: foo

일어난 일은 이렇습니다:

옵션 없이 스크립트를 실행하면 아무것도 표준 출력에 표시되지 않습니다. 별로 유용하지 않습니다.

두 번째는 argparse 모듈의 쓸모를 보여주기 시작합니다. 거의 아무것도 하지 않았지만 이미 도움말을 얻었습니다.

--help 옵션은, -h 로 단축할 수도 있습니다, 무료로 얻을 수 있는 유일한 옵션입니다 (즉, 지정할 필요가 없습니다). 다른 값을 지정하면 오류가 발생합니다. 그러나 그때조차도 우리는 사용 안내를 얻습니다, 여전히 공짜입니다.

위치 인자 소개

예:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("echo")
args = parser.parse_args()
print(args.echo)

코드를 실행합니다:

$ python prog.py
usage: prog.py [-h] echo
prog.py: error: the following arguments are required: echo
$ python prog.py --help
usage: prog.py [-h] echo

positional arguments:
  echo

options:
  -h, --help  show this help message and exit
$ python prog.py foo
foo

이런 일이 일어났습니다:

We’ve added the add_argument() method, which is what we use to specify which command-line options the program is willing to accept. In this case, I’ve named it echo so that it’s in line with its function.

이제 프로그램을 호출하려면 옵션을 지정해야 합니다.

The parse_args() method actually returns some data from the options specified, in this case, echo.

변수는 argparse 이 공짜로 수행하는 일종의 ‘마법’ 입니다 (즉, 값이 저장되는 변수를 지정할 필요가 없습니다). 또한, 그 이름이 메서드에 주어진 문자열 인자 echo 와 일치함을 알 수 있습니다.

그러나 도움말이 멋지게 보이지만, 현재로서는 가능한 최선이 아닙니다. 예를 들어 echo 가 위치 인자임을 볼 수 있지만, 추측하거나 소스 코드를 읽는 것 외에는 그것이 무엇을 하는지 모릅니다. 그럼 좀 더 유용하게 만들어 봅시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("echo", help="echo the string you use here")
args = parser.parse_args()
print(args.echo)

그러면 이렇게 됩니다:

$ python prog.py -h
usage: prog.py [-h] echo

positional arguments:
  echo        echo the string you use here

options:
  -h, --help  show this help message and exit

이제, 뭔가 더 쓸모있는 일을 하는 것은 어떻습니까:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", help="display a square of a given number")
args = parser.parse_args()
print(args.square**2)

다음은 코드를 실행한 결과입니다:

$ python prog.py 4
Traceback (most recent call last):
  File "prog.py", line 5, in <module>
    print(args.square**2)
TypeError: unsupported operand type(s) for ** or pow(): 'str' and 'int'

잘 안됐습니다. 우리가 달리 지시하지 않는다면, argparse 는 우리가 준 옵션들을 문자열로 취급하기 때문입니다. 그럼, argparse 에게 그 입력을 정수로 취급하라고 알려줍시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", help="display a square of a given number",
                    type=int)
args = parser.parse_args()
print(args.square**2)

다음은 코드를 실행한 결과입니다:

$ python prog.py 4
16
$ python prog.py four
usage: prog.py [-h] square
prog.py: error: argument square: invalid int value: 'four'

잘 됩니다. 이제 이 프로그램은 잘못된 입력이 올 때 더 진행하지 않고 종료하기조차 합니다.

옵션 인자 소개

지금까지 우리는 위치 인자를 다뤘습니다. 옵션 인자를 추가하는 방법에 대해 살펴봅시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--verbosity", help="increase output verbosity")
args = parser.parse_args()
if args.verbosity:
    print("verbosity turned on")

출력은 이렇습니다:

$ python prog.py --verbosity 1
verbosity turned on
$ python prog.py
$ python prog.py --help
usage: prog.py [-h] [--verbosity VERBOSITY]

options:
  -h, --help            show this help message and exit
  --verbosity VERBOSITY
                        increase output verbosity
$ python prog.py --verbosity
usage: prog.py [-h] [--verbosity VERBOSITY]
prog.py: error: argument --verbosity: expected one argument

일어난 일은 이렇습니다:

이 프로그램은 --verbosity 가 지정되었을 때 어떤 것을 표시하고 그렇지 않을 때는 아무것도 표시하지 않도록 작성되었습니다.

To show that the option is actually optional, there is no error when running the program without it. Note that by default, if an optional argument isn’t used, the relevant variable, in this case args.verbosity, is given None as a value, which is the reason it fails the truth test of the if statement.

도움말 메시지가 약간 달라졌습니다.

--verbosity 옵션을 사용할 때, 어떤 값을 지정해야 합니다. 어떤 값이건 상관없습니다.

위의 예제는 --verbosity 에 임의의 정숫값을 허용하지만, 우리의 간단한 프로그램에서는 실제로 True 또는 False 두 값만 쓸모 있습니다. 그것에 맞게 코드를 수정합시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--verbose", help="increase output verbosity",
                    action="store_true")
args = parser.parse_args()
if args.verbose:
    print("verbosity turned on")

출력은 이렇습니다:

$ python prog.py --verbose
verbosity turned on
$ python prog.py --verbose 1
usage: prog.py [-h] [--verbose]
prog.py: error: unrecognized arguments: 1
$ python prog.py --help
usage: prog.py [-h] [--verbose]

options:
  -h, --help  show this help message and exit
  --verbose   increase output verbosity

일어난 일은 이렇습니다:

The option is now more of a flag than something that requires a value. We even changed the name of the option to match that idea. Note that we now specify a new keyword, action, and give it the value "store_true". This means that, if the option is specified, assign the value True to args.verbose. Not specifying it implies False.

값을 지정하면 불평하는데, 플래그의 정의를 따르고 있습니다.

도움말 텍스트가 바뀐 것을 확인하십시오.

짧은 옵션

명령행 사용법에 익숙하다면 짧은 옵션 버전에 관한 내용을 아직 다루지 않았음을 알 수 있을 겁니다. 아주 간단합니다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("-v", "--verbose", help="increase output verbosity",
                    action="store_true")
args = parser.parse_args()
if args.verbose:
    print("verbosity turned on")

그러면 이렇게 됩니다:

$ python prog.py -v
verbosity turned on
$ python prog.py --help
usage: prog.py [-h] [-v]

options:
  -h, --help     show this help message and exit
  -v, --verbose  increase output verbosity

새로운 기능은 도움말 텍스트에도 반영됩니다.

위치 및 옵션 인자 결합하기

프로그램이 점점 복잡해지고 있습니다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbose", action="store_true",
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbose:
    print(f"the square of {args.square} equals {answer}")
else:
    print(answer)

이제 출력은 이렇게 됩니다:

$ python prog.py
usage: prog.py [-h] [-v] square
prog.py: error: the following arguments are required: square
$ python prog.py 4
16
$ python prog.py 4 --verbose
the square of 4 equals 16
$ python prog.py --verbose 4
the square of 4 equals 16

위치 인자를 다시 도입했기 때문에, 불평합니다.

순서는 중요하지 않습니다.

이 프로그램에 여러 상세도를 지정할 수 있도록 하는 능력을 다시 부여하고, 실제로 그것을 사용하는 것은 어떨까요:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbosity", type=int,
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbosity == 2:
    print(f"the square of {args.square} equals {answer}")
elif args.verbosity == 1:
    print(f"{args.square}^2 == {answer}")
else:
    print(answer)

출력은 이렇습니다:

$ python prog.py 4
16
$ python prog.py 4 -v
usage: prog.py [-h] [-v VERBOSITY] square
prog.py: error: argument -v/--verbosity: expected one argument
$ python prog.py 4 -v 1
4^2 == 16
$ python prog.py 4 -v 2
the square of 4 equals 16
$ python prog.py 4 -v 3
16

우리 프로그램의 버그를 드러내는 마지막 것을 제외하고는 그럴듯해 보입니다. --verbosity 옵션이 받아들일 수 있는 값을 제한해서 고쳐봅시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbosity", type=int, choices=[0, 1, 2],
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbosity == 2:
    print(f"the square of {args.square} equals {answer}")
elif args.verbosity == 1:
    print(f"{args.square}^2 == {answer}")
else:
    print(answer)

출력은 이렇습니다:

$ python prog.py 4 -v 3
usage: prog.py [-h] [-v {0,1,2}] square
prog.py: error: argument -v/--verbosity: invalid choice: 3 (choose from 0, 1, 2)
$ python prog.py 4 -h
usage: prog.py [-h] [-v {0,1,2}] square

positional arguments:
  square                display a square of a given number

options:
  -h, --help            show this help message and exit
  -v, --verbosity {0,1,2}
                        increase output verbosity

변경 내용은 오류 메시지와 도움말 문자열에도 반영됩니다.

이제 상세도를 다루는 다른 접근법을 사용해 봅시다, 이 방법은 꽤 널리 사용됩니다. 또한, 이 방법은 CPython 실행 파일이 자신의 상세도를 처리하는 방식과도 일치합니다 (python --help 의 결과를 확인하십시오):

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display the square of a given number")
parser.add_argument("-v", "--verbosity", action="count",
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbosity == 2:
    print(f"the square of {args.square} equals {answer}")
elif args.verbosity == 1:
    print(f"{args.square}^2 == {answer}")
else:
    print(answer)

We have introduced another action, “count”, to count the number of occurrences of specific options.

$ python prog.py 4
16
$ python prog.py 4 -v
4^2 == 16
$ python prog.py 4 -vv
the square of 4 equals 16
$ python prog.py 4 --verbosity --verbosity
the square of 4 equals 16
$ python prog.py 4 -v 1
usage: prog.py [-h] [-v] square
prog.py: error: unrecognized arguments: 1
$ python prog.py 4 -h
usage: prog.py [-h] [-v] square

positional arguments:
  square           display a square of a given number

options:
  -h, --help       show this help message and exit
  -v, --verbosity  increase output verbosity
$ python prog.py 4 -vvv
16

예, 이제 이전 버전의 스크립트처럼 (action="store_true" 와 유사하게) 플래그가 되었습니다. 출력되는 불평이 설명됩니다.

또한 “store_true” 액션과 비슷하게 작동하기도 합니다.

이제 여기에서 “count” 액션이 제공하는 것을 보여줍니다. 이런 종류의 사용법을 전에도 보았을 것입니다.

그리고, -v 플래그를 지정하지 않으면 그 플래그는 None 값으로 간주합니다.

예측하듯이, 플래그의 긴 형식을 지정하면, 같은 출력이 얻어져야 합니다.

안타깝게도 스크립트가 얻은 새로운 기능에 대한 도움말 출력은 그다지 유익하지 않지만, 스크립트의 문서를 개선하면 항상 해결할 수 있습니다 (예, help 키워드 인자를 사용해서).

마지막 출력은 우리 프로그램의 버그를 노출합니다.

고칩시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbosity", action="count",
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2

# bugfix: replace == with >=
if args.verbosity >= 2:
    print(f"the square of {args.square} equals {answer}")
elif args.verbosity >= 1:
    print(f"{args.square}^2 == {answer}")
else:
    print(answer)

그러면 이렇게 됩니다:

$ python prog.py 4 -vvv
the square of 4 equals 16
$ python prog.py 4 -vvvv
the square of 4 equals 16
$ python prog.py 4
Traceback (most recent call last):
  File "prog.py", line 11, in <module>
    if args.verbosity >= 2:
TypeError: '>=' not supported between instances of 'NoneType' and 'int'

첫 번째 출력은 잘 동작하고, 앞에서 나온 버그를 고칩니다. 즉, 2보다 크거나 같은 (>=) 모든 값을 최대의 상세도로 취급하고 싶습니다.

세 번째 결과가 좋지 않습니다.

이 버그를 고쳐 봅시다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("square", type=int,
                    help="display a square of a given number")
parser.add_argument("-v", "--verbosity", action="count", default=0,
                    help="increase output verbosity")
args = parser.parse_args()
answer = args.square**2
if args.verbosity >= 2:
    print(f"the square of {args.square} equals {answer}")
elif args.verbosity >= 1:
    print(f"{args.square}^2 == {answer}")
else:
    print(answer)

또 다른 키워드 default 를 소개했습니다. 다른 int 값과 비교하기 위해 0 으로 설정했습니다. 기본적으로, 옵션 인자가 지정되지 않으면 None 값을 갖게 되고, 그것은 int 값과 비교될 수 없음을 (그래서 TypeError 예외를 일으킵니다) 기억하십시오.

그리고:

$ python prog.py 4
16

여러분은 지금까지 배운 것만으로도 아주 멀리 갈 수 있으며, 우리는 단지 표면을 긁었을 뿐입니다. argparse 모듈은 매우 강력합니다. 이 자습서를 끝내기 전에 좀 더 탐색해 보겠습니다.

조금 더 발전시키기

우리의 작은 프로그램을 확장하여 제곱만이 아닌 다른 거듭제곱을 수행하기를 원하면 어떻게 될까요:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("x", type=int, help="the base")
parser.add_argument("y", type=int, help="the exponent")
parser.add_argument("-v", "--verbosity", action="count", default=0)
args = parser.parse_args()
answer = args.x**args.y
if args.verbosity >= 2:
    print(f"{args.x} to the power {args.y} equals {answer}")
elif args.verbosity >= 1:
    print(f"{args.x}^{args.y} == {answer}")
else:
    print(answer)

출력:

$ python prog.py
usage: prog.py [-h] [-v] x y
prog.py: error: the following arguments are required: x, y
$ python prog.py -h
usage: prog.py [-h] [-v] x y

positional arguments:
  x                the base
  y                the exponent

options:
  -h, --help       show this help message and exit
  -v, --verbosity
$ python prog.py 4 2 -v
4^2 == 16

지금까지는 표시되는 텍스트를 변경 하기 위해 상세도를 사용했습니다. 다음 예제는 대신 더 많은 텍스트를 표시하기 위해 상세도를 사용합니다:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument("x", type=int, help="the base")
parser.add_argument("y", type=int, help="the exponent")
parser.add_argument("-v", "--verbosity", action="count", default=0)
args = parser.parse_args()
answer = args.x**args.y
if args.verbosity >= 2:
    print(f"Running '{__file__}'")
if args.verbosity >= 1:
    print(f"{args.x}^{args.y} == ", end="")
print(answer)

출력:

$ python prog.py 4 2
16
$ python prog.py 4 2 -v
4^2 == 16
$ python prog.py 4 2 -vv
Running 'prog.py'
4^2 == 16

Specifying ambiguous arguments

When there is ambiguity in deciding whether an argument is positional or for an argument, -- can be used to tell parse_args() that everything after that is a positional argument:

>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('-n', nargs='+')
>>> parser.add_argument('args', nargs='*')

>>> # ambiguous, so parse_args assumes it's an option
>>> parser.parse_args(['-f'])
usage: PROG [-h] [-n N [N ...]] [args ...]
PROG: error: unrecognized arguments: -f

>>> parser.parse_args(['--', '-f'])
Namespace(args=['-f'], n=None)

>>> # ambiguous, so the -n option greedily accepts arguments
>>> parser.parse_args(['-n', '1', '2', '3'])
Namespace(args=[], n=['1', '2', '3'])

>>> parser.parse_args(['-n', '1', '--', '2', '3'])
Namespace(args=['2', '3'], n=['1'])

충돌하는 옵션들

So far, we have been working with two methods of an argparse.ArgumentParser instance. Let’s introduce a third one, add_mutually_exclusive_group(). It allows for us to specify options that conflict with each other. Let’s also change the rest of the program so that the new functionality makes more sense: we’ll introduce the --quiet option, which will be the opposite of the --verbose one:

import argparse

parser = argparse.ArgumentParser()
group = parser.add_mutually_exclusive_group()
group.add_argument("-v", "--verbose", action="store_true")
group.add_argument("-q", "--quiet", action="store_true")
parser.add_argument("x", type=int, help="the base")
parser.add_argument("y", type=int, help="the exponent")
args = parser.parse_args()
answer = args.x**args.y

if args.quiet:
    print(answer)
elif args.verbose:
    print(f"{args.x} to the power {args.y} equals {answer}")
else:
    print(f"{args.x}^{args.y} == {answer}")

프로그램은 이제 더 간단 해졌으며, 데모를 위해 일부 기능을 잃어버렸습니다. 어쨌든, 출력은 이렇습니다:

$ python prog.py 4 2
4^2 == 16
$ python prog.py 4 2 -q
16
$ python prog.py 4 2 -v
4 to the power 2 equals 16
$ python prog.py 4 2 -vq
usage: prog.py [-h] [-v | -q] x y
prog.py: error: argument -q/--quiet: not allowed with argument -v/--verbose
$ python prog.py 4 2 -v --quiet
usage: prog.py [-h] [-v | -q] x y
prog.py: error: argument -q/--quiet: not allowed with argument -v/--verbose

따라가기 쉽습니다. 여러분이 얻는 유연성을 볼 수 있도록 마지막 출력을 추가했습니다. 즉, 긴 형식 옵션을 짧은 형식 옵션과 섞어 쓸 수 있습니다.

결론을 내리기 전에, 여러분은 아마도 사용자들이 모를 경우를 대비해서 프로그램의 주요 목적을 알려주기를 원할 것입니다:

import argparse

parser = argparse.ArgumentParser(description="calculate X to the power of Y")
group = parser.add_mutually_exclusive_group()
group.add_argument("-v", "--verbose", action="store_true")
group.add_argument("-q", "--quiet", action="store_true")
parser.add_argument("x", type=int, help="the base")
parser.add_argument("y", type=int, help="the exponent")
args = parser.parse_args()
answer = args.x**args.y

if args.quiet:
    print(answer)
elif args.verbose:
    print(f"{args.x} to the power {args.y} equals {answer}")
else:
    print(f"{args.x}^{args.y} == {answer}")

사용법 텍스트의 약간의 차이점에 유의하십시오. [-v | -q] 에 주목해야 하는데, -v 나 -q 를 사용할 수 있지만 동시에 둘 다를 사용할 수는 없다는 뜻입니다:

$ python prog.py --help
usage: prog.py [-h] [-v | -q] x y

calculate X to the power of Y

positional arguments:
  x              the base
  y              the exponent

options:
  -h, --help     show this help message and exit
  -v, --verbose
  -q, --quiet

How to translate the argparse output

The output of the argparse module such as its help text and error messages are all made translatable using the gettext module. This allows applications to easily localize messages produced by argparse. See also 프로그램과 모듈의 국제화.

For instance, in this argparse output:

$ python prog.py --help
usage: prog.py [-h] [-v | -q] x y

calculate X to the power of Y

positional arguments:
  x              the base
  y              the exponent

options:
  -h, --help     show this help message and exit
  -v, --verbose
  -q, --quiet

The strings usage:, positional arguments:, options: and show this help message and exit are all translatable.

In order to translate these strings, they must first be extracted into a .po file. For example, using Babel [https://babel.pocoo.org/], run this command:

$ pybabel extract -o messages.po /usr/lib/python3.12/argparse.py

This command will extract all translatable strings from the argparse module and output them into a file named messages.po. This command assumes that your Python installation is in /usr/lib.

You can find out the location of the argparse module on your system using this script:

import argparse
print(argparse.__file__)

Once the messages in the .po file are translated and the translations are installed using gettext, argparse will be able to display the translated messages.

To translate your own strings in the argparse output, use gettext.

Custom type converters

The argparse module allows you to specify custom type converters for your command-line arguments. This allows you to modify user input before it’s stored in the argparse.Namespace. This can be useful when you need to pre-process the input before it is used in your program.

When using a custom type converter, you can use any callable that takes a single string argument (the argument value) and returns the converted value. However, if you need to handle more complex scenarios, you can use a custom action class with the action parameter instead.

For example, let’s say you want to handle arguments with different prefixes and process them accordingly:

import argparse

parser = argparse.ArgumentParser(prefix_chars='-+')

parser.add_argument('-a', metavar='<value>', action='append',
                    type=lambda x: ('-', x))
parser.add_argument('+a', metavar='<value>', action='append',
                    type=lambda x: ('+', x))

args = parser.parse_args()
print(args)

출력:

$ python prog.py -a value1 +a value2
Namespace(a=[('-', 'value1'), ('+', 'value2')])

In this example, we:

Created a parser with custom prefix characters using the prefix_chars parameter.

Defined two arguments, -a and +a, which used the type parameter to create custom type converters to store the value in a tuple with the prefix.

Without the custom type converters, the arguments would have treated the -a and +a as the same argument, which would have been undesirable. By using custom type converters, we were able to differentiate between the two arguments.

맺음말

argparse 모듈은 여기에 제시된 것보다 훨씬 많은 것을 제공합니다. 문서는 아주 상세하고 철저하며 예제가 풍부합니다. 이 자습서를 끝내면 압도감 없이 쉽게 소화할 수 있을 겁니다.

Upgrading optparse code

Originally, the argparse module had attempted to maintain compatibility with optparse. However, optparse was difficult to extend transparently, particularly with the changes required to support nargs= specifiers and better usage messages. When most everything in optparse had either been copy-pasted over or monkey-patched, it no longer seemed practical to try to maintain the backwards compatibility.

The argparse module improves on the optparse module in a number of ways including:

Handling positional arguments.

Supporting subcommands.

Allowing alternative option prefixes like + and /.

Handling zero-or-more and one-or-more style arguments.

Producing more informative usage messages.

Providing a much simpler interface for custom type and action.

A partial upgrade path from optparse to argparse:

Replace all optparse.OptionParser.add_option() calls with ArgumentParser.add_argument() calls.

Replace (options, args) = parser.parse_args() with args = parser.parse_args() and add additional ArgumentParser.add_argument() calls for the positional arguments. Keep in mind that what was previously called options, now in the argparse context is called args.

Replace optparse.OptionParser.disable_interspersed_args() by using parse_intermixed_args() instead of parse_args().

Replace callback actions and the callback_* keyword arguments with type or action arguments.

Replace string names for type keyword arguments with the corresponding type objects (e.g. int, float, complex, etc).

Replace optparse.Values with Namespace and optparse.OptionError and optparse.OptionValueError with ArgumentError.

Replace strings with implicit arguments such as %default or %prog with the standard Python syntax to use dictionaries to format strings, that is, %(default)s and %(prog)s.

Replace the OptionParser constructor version argument with a call to parser.add_argument('--version', action='version', version='<the version>').

logging — Logging facility for Python

소스 코드: Lib/logging/__init__.py [https://github.com/python/cpython/tree/main/Lib/logging/__init__.py]

Important

이 페이지는 API 레퍼런스 정보를 담고 있습니다. 자습서 정보 및 고급 주제에 대한 설명은 다음을 참조하십시오.

기초 자습서

고급 자습서

로깅 요리책

이 모듈은 응용 프로그램과 라이브러리를 위한 유연한 이벤트 로깅 시스템을 구현하는 함수와 클래스를 정의합니다.

표준 라이브러리 모듈로 로깅 API를 제공하는 것의 주요 이점은, 모든 파이썬 모듈이 로깅에 참여할 수 있어서, 응용 프로그램 로그에 여러분 자신의 메시지를 제삼자 모듈의 메시지와 통합할 수 있다는 것입니다.

Here’s a simple example of idiomatic usage:

# myapp.py
import logging
import mylib
logger = logging.getLogger(__name__)

def main():
    logging.basicConfig(filename='myapp.log', level=logging.INFO)
    logger.info('Started')
    mylib.do_something()
    logger.info('Finished')

if __name__ == '__main__':
    main()

# mylib.py
import logging
logger = logging.getLogger(__name__)

def do_something():
    logger.info('Doing something')

If you run myapp.py, you should see this in myapp.log:

INFO:__main__:Started
INFO:mylib:Doing something
INFO:__main__:Finished

The key feature of this idiomatic usage is that the majority of code is simply creating a module level logger with getLogger(__name__), and using that logger to do any needed logging. This is concise, while allowing downstream code fine-grained control if needed. Logged messages to the module-level logger get forwarded to handlers of loggers in higher-level modules, all the way up to the highest-level logger known as the root logger; this approach is known as hierarchical logging.

For logging to be useful, it needs to be configured: setting the levels and destinations for each logger, potentially changing how specific modules log, often based on command-line arguments or application configuration. In most cases, like the one above, only the root logger needs to be so configured, since all the lower level loggers at module level eventually forward their messages to its handlers. basicConfig() provides a quick way to configure the root logger that handles many use cases.

The module provides a lot of functionality and flexibility. If you are unfamiliar with logging, the best way to get to grips with it is to view the tutorials (see the links above and on the right).

The basic classes defined by the module, together with their attributes and methods, are listed in the sections below.

로거는 응용 프로그램 코드가 직접 사용하는 인터페이스를 노출합니다.

처리기는 (로거가 만든) 로그 레코드를 적절한 목적지로 보냅니다.

필터는 출력할 로그 레코드를 결정하기 위한 더 세분된 기능을 제공합니다.

포매터는 최종 출력에서 로그 레코드의 배치를 지정합니다.

Logger 객체

로거에는 다음과 같은 어트리뷰트와 메서드가 있습니다. 로거는 결코 직접 인스턴스를 만드는 일 없이, 항상 모듈 수준의 함수 logging.getLogger(name) 를 거치는 것에 주의하십시오. 같은 이름(name)으로 getLogger() 를 여러 번 호출해도 항상 같은 로거 객체에 대한 참조를 돌려줍니다.

The name is potentially a period-separated hierarchical value, like foo.bar.baz (though it could also be just plain foo, for example). Loggers that are further down in the hierarchical list are children of loggers higher up in the list. For example, given a logger with a name of foo, loggers with names of foo.bar, foo.bar.baz, and foo.bam are all descendants of foo. In addition, all loggers are descendants of the root logger. The logger name hierarchy is analogous to the Python package hierarchy, and identical to it if you organise your loggers on a per-module basis using the recommended construction logging.getLogger(__name__). That’s because in a module, __name__ is the module’s name in the Python package namespace.

class logging.Logger

name

This is the logger’s name, and is the value that was passed to getLogger() to obtain the logger.

참고

This attribute should be treated as read-only.

level

The threshold of this logger, as set by the setLevel() method.

참고

Do not set this attribute directly - always use setLevel(), which has checks for the level passed to it.

parent

The parent logger of this logger. It may change based on later instantiation of loggers which are higher up in the namespace hierarchy.

참고

This value should be treated as read-only.

propagate

이 어트리뷰트가 참으로 평가되면, 이 로거에 로그 된 이벤트는 이 로거에 첨부된 처리기뿐 아니라 상위 계층 (조상) 로거의 처리기로 전달됩니다. 메시지는 조상 로거의 처리기에 직접 전달됩니다 - 조상 로거의 수준이나 필터는 고려하지 않습니다.

이 값이 거짓으로 평가되면, 로깅 메시지가 조상 로거의 처리기로 전달되지 않습니다.

Spelling it out with an example: If the propagate attribute of the logger named A.B.C evaluates to true, any event logged to A.B.C via a method call such as logging.getLogger('A.B.C').error(...) will [subject to passing that logger’s level and filter settings] be passed in turn to any handlers attached to loggers named A.B, A and the root logger, after first being passed to any handlers attached to A.B.C. If any logger in the chain A.B.C, A.B, A has its propagate attribute set to false, then that is the last logger whose handlers are offered the event to handle, and propagation stops at that point.

생성자는 이 어트리뷰트를 True 로 설정합니다.

참고

로거 와 하나 이상의 조상에 처리기를 중복해서 연결하면, 같은 레코드를 여러 번 출력할 수 있습니다. 일반적으로, 하나 이상의 로거에 처리기를 붙일 필요는 없습니다. 로거 계층에서 가장 높은 적절한 로거에 처리기를 연결하면, propagate 설정이 True 로 남아있는 모든 자식 로거들이 로그 하는 모든 이벤트를 보게 됩니다. 일반적인 시나리오는 루트 로거에만 처리기를 연결하고, 전파가 나머지를 처리하도록 하는 것입니다.

handlers

The list of handlers directly attached to this logger instance.

참고

This attribute should be treated as read-only; it is normally changed via the addHandler() and removeHandler() methods, which use locks to ensure thread-safe operation.

disabled

This attribute disables handling of any events. It is set to False in the initializer, and only changed by logging configuration code.

참고

This attribute should be treated as read-only.

setLevel(level)

이 로거의 수준 경계를 level 로 설정합니다. level 보다 덜 심각한 로깅 메시지는 무시됩니다; 심각도 level 이상의 로깅 메시지는, 처리기 수준이 level 보다 높은 심각도 수준으로 설정되지 않는 한, 이 로거에 연결된 처리기가 출력합니다.

로거가 만들어질 때, 수준은 NOTSET (로거가 루트 로거 일 때는 모든 메시지를 처리하게 하고, 로거가 루트 로거가 아니면 모든 메시지를 부모에게 위임하도록 합니다) 으로 설정됩니다. 루트 로거는 수준 WARNING으로 만들어짐에 유의하세요.

‘부모에게 위임’이라는 말은, 로거 수준이 NOTSET 인 경우, NOTSET 이외의 수준을 갖는 조상이 발견되거나 루트에 도달할 때까지 조상 로거 체인을 탐색함을 의미합니다.

NOTSET 이외의 수준을 갖는 조상이 발견되면, 그 조상의 수준을 조상 검색이 시작된 로거의 유효 수준으로 간주하여, 로깅 이벤트를 처리할지를 결정하는 데 사용됩니다.

루트에 도달하면, 그리고 루트가 NOTSET 수준을 갖고 있으면, 모든 메시지가 처리됩니다. 그렇지 않으면 루트 수준이 유효 수준으로 사용됩니다.

수준의 목록은 로깅 수준를 보세요.

버전 3.2에서 변경: level 매개 변수는 이제 INFO와 같은 정수 상수 대신 ‘INFO’와 같은 수준의 문자열 표현을 허용합니다. 그러나 수준은 내부적으로 정수로 저장되며, getEffectiveLevel() 및 isEnabledFor()와 같은 메서드는 정수를 반환하거나 정수가 전달되기를 기대합니다.

isEnabledFor(level)

심각도 level 의 메시지가 이 로거에서 처리될지를 알려줍니다. 이 메서드는 먼저 logging.disable(level) 에 의해 설정된 모듈 수준의 수준을 확인한 다음, getEffectiveLevel()로 확인되는 로거의 유효 수준을 검사합니다.

getEffectiveLevel()

이 로거의 유효 수준을 알려줍니다. setLevel() 을 사용하여 NOTSET 이외의 값이 설정되면, 그 값이 반환됩니다. 그렇지 않으면, NOTSET 이외의 값이 발견될 때까지 루트를 향해 계층 구조를 탐색하고, 그 값이 반환됩니다. 반환되는 값은 정수이며, 일반적으로 logging.DEBUG, logging.INFO 등 중 하나입니다.

getChild(suffix)

접미사에 의해 결정되는, 이 로거의 자손 로거를 반환합니다. 그러므로, logging.getLogger('abc').getChild('def.ghi') 는 logging.getLogger('abc.def.ghi') 와 같은 로거를 반환합니다. 이것은 편의 메서드인데, 부모 로거가 리터럴 문자열이 아닌 이름(가령 __name__)을 사용하여 명명될 때 유용합니다.

Added in version 3.2.

getChildren()

Returns a set of loggers which are immediate children of this logger. So for example logging.getLogger().getChildren() might return a set containing loggers named foo and bar, but a logger named foo.bar wouldn’t be included in the set. Likewise, logging.getLogger('foo').getChildren() might return a set including a logger named foo.bar, but it wouldn’t include one named foo.bar.baz.

Added in version 3.12.

debug(msg, *args, **kwargs)

이 로거에 수준 DEBUG 메시지를 로그 합니다. msg 는 메시지 포맷 문자열이고, args 는 문자열 포매팅 연산자를 사용하여 msg 에 병합되는 인자입니다. (이는 포맷 문자열에 키워드를 사용하고, 인자로 하나의 딕셔너리를 전달할 수 있음을 의미합니다.) args가 제공되지 않으면 msg에 % 포매팅 연산이 수행되지 않습니다.

kwargs 에서 검사되는 네 개의 키워드 인자가 있습니다: exc_info, stack_info, stacklevel 및 extra.

exc_info 가 거짓으로 평가되지 않으면, 로깅 메시지에 예외 정보가 추가됩니다. 예외 튜플 (sys.exc_info() 에 의해 반환되는 형식) 또는 예외 인스턴스가 제공되면 사용됩니다; 그렇지 않으면 예외 정보를 얻기 위해 sys.exc_info() 를 호출합니다.

두 번째 선택적 키워드 인자는 stack_info 이며, 기본값은 False 입니다. 참이면, 실제 로깅 호출을 포함하는 스택 정보가 로깅 메시지에 추가됩니다. 이것은 exc_info 를 지정할 때 표시되는 것과 같은 스택 정보가 아닙니다: 전자(stack_info)는 스택의 맨 아래에서 현재 스레드의 로깅 호출까지의 스택 프레임이며, 후자(exc_info)는 예외가 일어난 후에 예외 처리기를 찾으면서 되감은 스택 프레임에 대한 정보입니다.

exc_info 와는 독립적으로 stack_info 를 지정할 수 있습니다. 예를 들어 예외가 발생하지 않은 경우에도 코드의 특정 지점에 어떻게 도달했는지 보여줄 수 있습니다. 스택 프레임은 다음과 같은 헤더 행 다음에 인쇄됩니다:

Stack (most recent call last):

예외 프레임을 표시할 때 사용되는 Traceback (most recent call last): 을 흉내 내고 있습니다.

세 번째 선택적 키워드 인자는 stacklevel이며, 기본값은 1입니다. 1보다 크면, 로깅 이벤트용으로 만들어진 LogRecord에 설정된 줄 번호와 함수 이름을 계산할 때 해당 수의 스택 프레임을 건너뜁니다. 기록된 함수 이름, 파일명 및 줄 번호가 도우미 함수/메서드에 대한 정보가 아니라 호출자의 정보가 되도록, 로깅 도우미에서 사용할 수 있습니다. 이 매개 변수의 이름은 warnings 모듈에 있는 비슷한 것과 같도록 맞췄습니다.

The fourth keyword argument is extra which can be used to pass a dictionary which is used to populate the __dict__ of the LogRecord created for the logging event with user-defined attributes. These custom attributes can then be used as you like. For example, they could be incorporated into logged messages. For example:

FORMAT = '%(asctime)s %(clientip)-15s %(user)-8s %(message)s'
logging.basicConfig(format=FORMAT)
d = {'clientip': '192.168.0.1', 'user': 'fbloggs'}
logger = logging.getLogger('tcpserver')
logger.warning('Protocol problem: %s', 'connection reset', extra=d)

는 이렇게 인쇄할 것입니다

2006-02-08 22:20:02,165 192.168.0.1 fbloggs  Protocol problem: connection reset

The keys in the dictionary passed in extra should not clash with the keys used by the logging system. (See the section on LogRecord 어트리뷰트 for more information on which keys are used by the logging system.)

로그 된 메시지에서 이러한 어트리뷰트를 사용하려면 몇 가지 주의를 기울여야 합니다. 위의 예에서, 예를 들어, Formatter 에 설정한 포맷 문자열은 LogRecord의 어트리뷰트 딕셔너리에 ‘clientip’ 과 ‘user’ 가 있을 것으로 기대하고 있습니다. 이것들이 없는 경우 문자열 포매팅 예외가 발생하기 때문에 메시지가 기록되지 않습니다. 따라서 이 경우, 항상 이 키를 포함하는 extra 딕셔너리를 전달해야 합니다.

성가신 일입니다만, 이 기능은 여러 문맥에서 같은 코드가 실행되고 관심 있는 조건들(가령 원격 클라이언트 IP 주소와 인증된 사용자 이름)이 문맥에 따라 발생하는 다중 스레드 서버와 같은 특수한 상황을 위한 것입니다. 이런 상황에서는, 특수한 Formatter 가 특정한 Handler와 함께 사용될 가능성이 큽니다.

If no handler is attached to this logger (or any of its ancestors, taking into account the relevant Logger.propagate attributes), the message will be sent to the handler set on lastResort.

버전 3.2에서 변경: stack_info 매개 변수가 추가되었습니다.

버전 3.5에서 변경: exc_info 매개 변수는 이제 예외 인스턴스를 받아들입니다.

버전 3.8에서 변경: stacklevel 매개 변수가 추가되었습니다.

info(msg, *args, **kwargs)

이 로거에 수준 INFO 메시지를 로그 합니다. 인자는 debug()처럼 해석됩니다.

warning(msg, *args, **kwargs)

이 로거에 수준 WARNING 메시지를 로그 합니다. 인자는 debug()처럼 해석됩니다.

참고

기능적으로 warning 와 같은, 구식의 warn 메서드가 있습니다. warn 은 폐지되었으므로 사용하지 마십시오 - 대신 warning 을 사용하십시오.

error(msg, *args, **kwargs)

이 로거에 수준 ERROR 메시지를 로그 합니다. 인자는 debug()처럼 해석됩니다.

critical(msg, *args, **kwargs)

이 로거에 수준 CRITICAL 메시지를 로그 합니다. 인자는 debug()처럼 해석됩니다.

log(level, msg, *args, **kwargs)

이 로거에 정수 수준 level 로 메시지를 로그 합니다. 다른 인자는 debug()처럼 해석됩니다.

exception(msg, *args, **kwargs)

이 로거에 수준 ERROR 메시지를 로그 합니다. 인자는 debug()처럼 해석됩니다. 예외 정보가 로깅 메시지에 추가됩니다. 이 메서드는 예외 처리기에서만 호출해야 합니다.

addFilter(filter)

지정된 필터 filter 를 이 로거에 추가합니다.

removeFilter(filter)

이 로거에서 지정된 필터 filter 를 제거합니다.

filter(record)

이 로거의 필터를 레코드(record)에 적용하고 레코드가 처리 대상이면 True를 반환합니다. 필터 중 어느 하나가 거짓 값을 반환할 때까지 필터는 차례로 참조됩니다. 그중 아무것도 거짓 값을 반환하지 않으면 레코드가 처리됩니다 (처리기로 전달됩니다). 어느 하나가 거짓 값을 반환하면, 더 이상의 레코드 처리는 이루어지지 않습니다.

addHandler(hdlr)

지정된 처리기 hdlr 를 이 로거에 추가합니다.

removeHandler(hdlr)

이 로거에서 지정된 처리기 hdlr 을 제거합니다.

findCaller(stack_info=False, stacklevel=1)

호출자의 소스 파일 이름과 행 번호를 찾습니다. 파일 이름, 행 번호, 함수 이름 및 스택 정보를 4-요소 튜플로 반환합니다. 스택 정보는 stack_info 가 True 가 아니면 None 으로 반환됩니다.

stacklevel 매개 변수는 debug()과 기타 API를 호출하는 코드에서 전달됩니다. 1보다 크면, 반환되는 값을 결정하기 전에 초과분만큼 스택 프레임을 건너뜁니다. 일반적으로 도무미/래퍼 코드에서 로깅 API를 호출할 때 유용한데, 이벤트 로그의 정보가 도우미/래퍼 코드가 아니라 호출자 코드를 참조하도록 합니다.

handle(record)

이 로거와 그 조상(거짓 값의 propagate 가 발견될 때까지)과 연관된 모든 처리기에 레코드를 전달하여 레코드를 처리합니다. 이 메서드는 로컬에서 만든 레코드뿐만 아니라 소켓에서 받아서 언피클된 레코드를 처리하는 데 사용됩니다. filter() 를 사용하여 로거 수준 필터링을 적용합니다.

makeRecord(name, level, fn, lno, msg, args, exc_info, func=None, extra=None, sinfo=None)

이 메서드는 특수한 LogRecord 인스턴스를 만들기 위해 서브 클래스에서 재정의할 수 있는 팩토리 메서드입니다.

hasHandlers()

이 로거에 처리기가 구성되어 있는지 확인합니다. 이 로거의 처리기와 로거 계층의 부모를 찾습니다. 처리기가 발견되면 True 를 반환하고, 그렇지 않으면 False 를 반환합니다. 이 메서드는 ‘propagate’ 어트리뷰트가 거짓으로 설정된 로거가 발견될 때 계층 구조 검색을 중지합니다 - 그 로거가 처리기가 있는지 검사하는 마지막 로거가 됩니다.

Added in version 3.2.

버전 3.7에서 변경: 이제 로거는 피클 되고 언피클 될 수 있습니다.

로깅 수준

로깅 수준의 숫자 값은 다음 표에 나와 있습니다. 여러분 자신의 수준을 정의하고, 미리 정의된 수준과 상대적인 특정 값을 갖도록 하려는 경우 필요합니다. 같은 숫자 값을 가진 수준을 정의하면 미리 정의된 값을 덮어씁니다; 미리 정의된 이름이 유실됩니다.

수준

숫자 값

What it means / When to use it

logging.NOTSET

0

When set on a logger, indicates that ancestor loggers are to be consulted to determine the effective level. If that still resolves to NOTSET, then all events are logged. When set on a handler, all events are handled.

logging.DEBUG

10

Detailed information, typically only of interest to a developer trying to diagnose a problem.

logging.INFO

20

Confirmation that things are working as expected.

logging.WARNING

30

An indication that something unexpected happened, or that a problem might occur in the near future (e.g. ‘disk space low’). The software is still working as expected.

logging.ERROR

40

Due to a more serious problem, the software has not been able to perform some function.

logging.CRITICAL

50

A serious error, indicating that the program itself may be unable to continue running.

Handler 객체

Handlers have the following attributes and methods. Note that Handler is never instantiated directly; this class acts as a base for more useful subclasses. However, the __init__() method in subclasses needs to call Handler.__init__().

class logging.Handler

__init__(level=NOTSET)

수준을 설정하고, 필터 목록을 빈 리스트로 설정하고, I/O 메커니즘에 대한 액세스를 직렬화하기 위해 (createLock() 을 사용하여) 록을 생성함으로써 Handler 인스턴스를 초기화합니다.

createLock()

스레드 안전하지 않은 하부 I/O 기능에 대한 액세스를 직렬화하는 데 사용할 수 있는 스레드 록을 초기화합니다.

acquire()

createLock() 로 생성된 스레드 록을 확보합니다.

release()

acquire()로 확보한 스레드 록을 반납합니다.

setLevel(level)

이 처리기의 수준 경계를 level 로 설정합니다. level 보다 덜 심각한 로깅 메시지는 무시됩니다. 처리기가 만들어질 때, 수준은 NOTSET (모든 메시지가 처리되게 합니다) 으로 설정됩니다.

수준의 목록은 로깅 수준를 보세요.

버전 3.2에서 변경: level 매개 변수는 이제 INFO와 같은 정수 상수 대신 ‘INFO’와 같은 수준 문자열 표현을 허용합니다.

setFormatter(fmt)

이 처리기의 Formatter를 fmt 로 설정합니다.

addFilter(filter)

지정된 필터 filter 를 이 처리기에 추가합니다.

removeFilter(filter)

이 처리기에서 지정된 필터 filter 를 제거합니다.

filter(record)

이 처리기의 필터를 레코드에 적용하고 레코드가 처리 대상이면 True를 반환합니다. 필터 중 어느 하나가 거짓 값을 반환할 때까지 필터는 차례로 확인됩니다. 그중 아무것도 거짓 값을 반환하지 않으면 레코드가 출력됩니다. 어느 하나가 거짓 값을 반환하면 처리기는 레코드를 출력하지 않습니다.

flush()

모든 로그 출력이 플러시 되었음을 확실히 합니다. 이 버전은 아무것도 하지 않으며, 서브 클래스에 의해 구현됩니다.

close()

처리기가 사용하는 자원을 정리합니다. 이 버전은 출력하지 않지만, shutdown() 이 호출 될 때 닫히는 처리기의 내부 목록에서 처리기를 제거합니다. 서브 클래스는 이것이 재정의된 close() 메서드에서 이 메서드를 호출해야 합니다.

handle(record)

처리기에 추가된 필터에 따라 조건부로, 지정된 로깅 레코드를 출력합니다. 레코드의 실제 출력을 I/O 스레드 록의 확보/해제로 둘러쌉니다.

handleError(record)

This method should be called from handlers when an exception is encountered during an emit() call. If the module-level attribute raiseExceptions is False, exceptions get silently ignored. This is what is mostly wanted for a logging system - most users will not care about errors in the logging system, they are more interested in application errors. You could, however, replace this with a custom handler if you wish. The specified record is the one which was being processed when the exception occurred. (The default value of raiseExceptions is True, as that is more useful during development).

format(record)

레코드를 포맷합니다 - 포매터가 설정된 경우 사용합니다. 그렇지 않으면 모듈의 기본 포매터를 사용합니다.

emit(record)

지정된 로깅 레코드를 실제로 로그 하는 데 필요한 작업을 수행합니다. 이 버전은 서브 클래스에 의해 구현될 것으로 보고 NotImplementedError를 발생시킵니다.

경고

This method is called after a handler-level lock is acquired, which is released after this method returns. When you override this method, note that you should be careful when calling anything that invokes other parts of the logging API which might do locking, because that might result in a deadlock. Specifically:

Logging configuration APIs acquire the module-level lock, and then individual handler-level locks as those handlers are configured.

Many logging APIs lock the module-level lock. If such an API is called from this method, it could cause a deadlock if a configuration call is made on another thread, because that thread will try to acquire the module-level lock before the handler-level lock, whereas this thread tries to acquire the module-level lock after the handler-level lock (because in this method, the handler-level lock has already been acquired).

표준으로 포함된 처리기 목록은 logging.handlers 를 참조하십시오.

Formatter 객체

class logging.Formatter(fmt=None, datefmt=None, style='%', validate=True, *, defaults=None)

Responsible for converting a LogRecord to an output string to be interpreted by a human or external system.

매개변수:

fmt (str) – A format string in the given style for the logged output as a whole. The possible mapping keys are drawn from the LogRecord object’s LogRecord 어트리뷰트. If not specified, '%(message)s' is used, which is just the logged message.

datefmt (str) – A format string in the given style for the date/time portion of the logged output. If not specified, the default described in formatTime() is used.

style (str) – Can be one of '%', '{' or '$' and determines how the format string will be merged with its data: using one of printf 스타일 문자열 포매팅 (%), str.format() ({) or string.Template ($). This only applies to fmt and datefmt (e.g. '%(message)s' versus '{message}'), not to the actual log messages passed to the logging methods. However, there are other ways to use {- and $-formatting for log messages.

validate (bool) – If True (the default), incorrect or mismatched fmt and style will raise a ValueError; for example, logging.Formatter('%(asctime)s - %(message)s', style='{').

defaults (dict[str, Any]) – A dictionary with default values to use in custom fields. For example, logging.Formatter('%(ip)s %(message)s', defaults={"ip": None})

버전 3.2에서 변경: Added the style parameter.

버전 3.8에서 변경: Added the validate parameter.

버전 3.10에서 변경: Added the defaults parameter.

format(record)

The record’s attribute dictionary is used as the operand to a string formatting operation. Returns the resulting string. Before formatting the dictionary, a couple of preparatory steps are carried out. The message attribute of the record is computed using msg % args. If the formatting string contains '(asctime)', formatTime() is called to format the event time. If there is exception information, it is formatted using formatException() and appended to the message. Note that the formatted exception information is cached in attribute exc_text. This is useful because the exception information can be pickled and sent across the wire, but you should be careful if you have more than one Formatter subclass which customizes the formatting of exception information. In this case, you will have to clear the cached value (by setting the exc_text attribute to None) after a formatter has done its formatting, so that the next formatter to handle the event doesn’t use the cached value, but recalculates it afresh.

스택 정보가 있는 경우, 예외 정보 뒤에 덧붙입니다. 필요할 경우 formatStack() 을 사용하여 변환합니다.

formatTime(record, datefmt=None)

이 메서드는 포맷된 시간을 사용하려는 포매터에 의해 format()에서 호출되어야 합니다. 이 메서드는 특정 요구 사항을 제공하기 위해 포매터에서 재정의될 수 있지만, 기본 동작은 다음과 같습니다: datefmt(문자열)이 지정된 경우, time.strftime() 를 사용하여 레코드 생성 시간을 포매팅합니다. 그렇지 않으면 ‘%Y-%m-%d %H:%M:%S,uuu’ 포맷이 사용됩니다. 여기서 uuu 부분은 밀리 초 값이고, 다른 문자들은 time.strftime() 설명서를 따릅니다. 이 포맷의 표현된 시간의 예는 2003-01-23 00:29:50,411 입니다. 결과 문자열이 반환됩니다.

이 함수는 사용자가 구성할 수 있는 함수를 사용하여 생성 시간을 튜플로 변환합니다. 기본적으로 time.localtime() 이 사용됩니다; 특정 포매터 인스턴스에서 이를 변경하려면, converter 어트리뷰트를 time.localtime() 또는 time.gmtime() 과 같은 서명을 가진 함수로 설정하십시오. 모든 포매터를 변경하려면, 예를 들어 모든 로깅 시간을 GMT로 표시하려면, Formatter 클래스의 converter 어트리뷰트를 설정하십시오.

버전 3.3에서 변경: 예전에는, 기본 포맷이 다음과 같이 하드 코딩되었습니다: 2010-09-06 22:38:15,292. 쉼표 앞에 있는 부분은 strptime 포맷 문자열('%Y-%m-%d %H:%M:%S')이며, 쉼표 뒤의 부분은 밀리 초 값입니다. strptime에 밀리 초 포맷 표시자가 없으므로, 밀리 초 값은 다른 포맷 문자열 '%s,%03d' 을 사용하여 추가됩니다 — 이 두 포맷 문자열 모두 이 메서드에 하드 코드 되었습니다. 이 변경으로, 이 문자열들은 클래스 수준 어트리뷰트로 정의되었고, 원하는 경우 인스턴스 수준에서 재정의할 수 있습니다. 어트리뷰트 이름은 default_time_format(strptime 포맷 문자열)과 default_msec_format(밀리 초 값 추가용)입니다.

버전 3.9에서 변경: default_msec_format은 None일 수 있습니다.

formatException(exc_info)

지정된 예외 정보(sys.exc_info() 에 의해 반환되는 표준 예외 튜플)를 문자열로 포맷합니다. 이 기본 구현은 traceback.print_exception()을 사용합니다. 결과 문자열이 반환됩니다.

formatStack(stack_info)

지정된 스택 정보(traceback.print_stack() 에 의해 반환된 문자열이지만 마지막 줄 바꿈이 제거됩니다)을 문자열로 포맷합니다. 이 기본 구현은 입력 값을 그대로 반환합니다.

class logging.BufferingFormatter(linefmt=None)

A base formatter class suitable for subclassing when you want to format a number of records. You can pass a Formatter instance which you want to use to format each line (that corresponds to a single record). If not specified, the default formatter (which just outputs the event message) is used as the line formatter.

formatHeader(records)

Return a header for a list of records. The base implementation just returns the empty string. You will need to override this method if you want specific behaviour, e.g. to show the count of records, a title or a separator line.

formatFooter(records)

Return a footer for a list of records. The base implementation just returns the empty string. You will need to override this method if you want specific behaviour, e.g. to show the count of records or a separator line.

format(records)

Return formatted text for a list of records. The base implementation just returns the empty string if there are no records; otherwise, it returns the concatenation of the header, each record formatted with the line formatter, and the footer.

Filter 객체

Filter 는 수준을 통해 제공되는 것보다 더 정교한 필터링을 위해 Handler 와 Logger 에 의해 사용될 수 있습니다. 베이스 필터 클래스는 로거 계층 구조의 특정 지점 아래에 있는 이벤트만 허용합니다. 예를 들어 ‘A.B’로 초기화된 필터는, 로거 ‘A.B’, ‘A.B.C’, ‘A.B.C.D’, ‘A.B.D’ 등이 로그 한 이벤트를 허용하지만, ‘A.BB’, ‘B.A.B’ 등은 허용하지 않습니다. 빈 문자열을 사용하면 모든 이벤트를 통과시킵니다.

class logging.Filter(name='')

Filter 클래스의 인스턴스를 반환합니다. name 을 제공하면, 필터를 통과하도록 허용할 로거(그 자식들도 포함합니다)의 이름을 지정합니다. name 이 빈 문자열이면, 모든 이벤트를 허용합니다.

filter(record)

Is the specified record to be logged? Returns false for no, true for yes. Filters can either modify log records in-place or return a completely different record instance which will replace the original log record in any future processing of the event.

처리기에 첨부된 필터는 이벤트를 처리기가 출력하기 전에 호출되는 반면, 로거에 첨부된 필터는 이벤트가 로깅될 때마다 (debug(), info() 등) 처리기로 이벤트를 보내기 전에 호출됩니다. 이는 자손 로거가 만든 이벤트들은, 같은 필터가 자손들에게도 적용되지 않는 한, 로거의 필터 설정으로 필터링 되지 않는다는 것을 뜻합니다.

실제로 Filter 의 서브 클래스를 만들 필요는 없습니다: 같은 의미가 있는 filter 메서드를 가진 인스턴스는 무엇이건 전달할 수 있습니다.

버전 3.2에서 변경: 특수한 Filter 클래스를 만들거나 filter 메서드를 가진 다른 클래스를 사용할 필요가 없습니다: 함수(또는 다른 콜러블)를 필터로 사용할 수 있습니다. 필터링 로직은 필터 객체가 filter 어트리뷰트를 가졌는지 확인합니다: 만약 있다면 Filter 라고 가정하고 filter() 메서드를 호출합니다. 그렇지 않으면 콜러블이라고 가정하고 레코드를 단일 매개 변수로 호출합니다. 반환된 값은 filter() 가 반환하는 값과 같은 의미를 지녀야 합니다.

버전 3.12에서 변경: You can now return a LogRecord instance from filters to replace the log record rather than modifying it in place. This allows filters attached to a Handler to modify the log record before it is emitted, without having side effects on other handlers.

필터는 수준보다 정교한 기준에 따라 레코드를 필터링하는 데 주로 사용되지만, 필터가 첨부되는 처리기나 로거에서 처리되는 모든 레코드를 볼 수 있습니다: 이 특성은, 특정 로거나 처리기가 얼마나 많은 레코드를 처리하는지 센다거나, 처리 중인 LogRecord에 어트리뷰트를 추가, 변경, 삭제하려고 할 때 유용합니다. 당연히, LogRecord를 변경하는 것은 주의를 필요로 하는 일이지만, 로그에 문맥 정보를 주입하는 것을 허용합니다 (문맥 정보 전달에 필터 사용하기를 보세요).

LogRecord 객체

LogRecord 인스턴스는 뭔가 로깅 될 때마다 Logger 에 의해 자동으로 생성되며, makeLogRecord()를 통해 수동으로 생성될 수 있습니다 (예를 들어, 네트워크에서 수신된 피클 된 이벤트의 경우).

class logging.LogRecord(name, level, pathname, lineno, msg, args, exc_info, func=None, sinfo=None)

로그 되는 이벤트와 관련된 모든 정보를 담고 있습니다.

The primary information is passed in msg and args, which are combined using msg % args to create the message attribute of the record.

매개변수:

name (str) – The name of the logger used to log the event represented by this LogRecord. Note that the logger name in the LogRecord will always have this value, even though it may be emitted by a handler attached to a different (ancestor) logger.

level (int) – The numeric level of the logging event (such as 10 for DEBUG, 20 for INFO, etc). Note that this is converted to two attributes of the LogRecord: levelno for the numeric value and levelname for the corresponding level name.

pathname (str) – The full string path of the source file where the logging call was made.

lineno (int) – 로깅 호출이 발생한 소스 파일의 행 번호.

msg (Any) – The event description message, which can be a %-format string with placeholders for variable data, or an arbitrary object (see 임의의 객체를 메시지로 사용하기).

args (tuple | dict[str, Any]) – 이벤트 설명을 얻기 위해 msg 인자에 병합할 변수 데이터.

exc_info (tuple[type[BaseException], BaseException, types.TracebackType] | None) – An exception tuple with the current exception information, as returned by sys.exc_info(), or None if no exception information is available.

func (str | None) – 로깅 호출을 호출한 함수 또는 메서드의 이름.

sinfo (str | None) – 현재 스레드에서 스택의 바닥부터 로깅 호출까지의 스택 정보를 나타내는 텍스트 문자열.

getMessage()

사용자가 제공 한 인자를 메시지와 병합한 후, 이 LogRecord 인스턴스에 대한 메시지를 반환합니다. 로깅 호출에 제공된 사용자 제공 메시지 인자가 문자열이 아닌 경우, str() 이 호출되어 문자열로 변환됩니다. 이렇게 해서 사용자 정의 클래스를 메시지로 사용할 수 있도록 하는데, 그 클래스의 __str__ 메서드는 사용할 실제 포맷 문자열을 반환 할 수 있습니다.

버전 3.2에서 변경: 레코드를 생성하는 데 사용되는 팩토리를 제공함으로써, LogRecord의 생성을 더 구성할 수 있게 만들었습니다. 팩토리는 getLogRecordFactory()와 setLogRecordFactory() (팩토리의 서명은 이곳을 참조하십시오) 를 사용하여 설정할 수 있습니다.

이 기능은 LogRecord 생성 시에 여러분 자신의 값을 주입하는데 사용할 수 있습니다. 다음과 같은 패턴을 사용할 수 있습니다:

old_factory = logging.getLogRecordFactory()

def record_factory(*args, **kwargs):
    record = old_factory(*args, **kwargs)
    record.custom_attribute = 0xdecafbad
    return record

logging.setLogRecordFactory(record_factory)

이 패턴을 사용하면 여러 팩토리를 체인으로 묶을 수 있으며, 서로의 어트리뷰트를 덮어쓰거나 위에 나열된 표준 어트리뷰트를 실수로 덮어쓰지 않는 한 놀랄만한 일이 일어나지는 않아야 합니다.

LogRecord 어트리뷰트

LogRecord에는 많은 어트리뷰트가 있으며, 대부분 어트리뷰트는 생성자의 매개 변수에서 옵니다. (LogRecord 생성자 매개 변수와 LogRecord 어트리뷰트의 이름이 항상 정확하게 일치하는 것은 아닙니다.) 이러한 어트리뷰트를 사용하여 레코드의 데이터를 포맷 문자열로 병합 할 수 있습니다. 다음 표는 어트리뷰트 이름, 의미와 해당 자리 표시자를 %-스타일 포맷 문자열로 (알파벳 순서로) 나열합니다.

{}-포매팅(str.format())을 사용한다면, {attrname} 을 포맷 문자열의 자리 표시자로 사용할 수 있습니다. $-포매팅(string.Template)을 사용하고 있다면, ${attrname} 형식을 사용하십시오. 두 경우 모두, 물론, attrname 을 사용하려는 실제 어트리뷰트 이름으로 대체하십시오.

In the case of {}-formatting, you can specify formatting flags by placing them after the attribute name, separated from it with a colon. For example: a placeholder of {msecs:03.0f} would format a millisecond value of 4 as 004. Refer to the str.format() documentation for full details on the options available to you.

어트리뷰트 이름

포맷

설명

args

직접 포맷할 필요는 없습니다.

message 를 생성하기 위해 msg 에 병합되는 인자의 튜플. 또는 (인자가 하나뿐이고 딕셔너리일 때) 병합을 위해 값이 사용되는 딕셔너리.

asctime

%(asctime)s

사람이 읽을 수 있는, LogRecord 가 생성된 시간. 기본적으로 ‘2003-07-08 16:49:45,896’ 형식입니다 (쉼표 뒤의 숫자는 밀리 초 부분입니다).

created

%(created)f

Time when the LogRecord was created (as returned by time.time_ns() / 1e9).

exc_info

직접 포맷할 필요는 없습니다.

예외 튜플 (sys.exc_info 에서 제공) 또는, 예외가 발생하지 않았다면, None.

filename

%(filename)s

pathname 의 파일명 부분.

funcName

%(funcName)s

로깅 호출을 포함하는 함수의 이름.

levelname

%(levelname)s

메시지의 텍스트 로깅 수준 ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL').

levelno

%(levelno)s

메시지의 숫자 로깅 수준 (DEBUG, INFO, WARNING, ERROR, CRITICAL).

lineno

%(lineno)d

로깅 호출이 일어난 소스 행 번호 (사용 가능한 경우).

message

%(message)s

로그 된 메시지. msg % args 로 계산됩니다. Formatter.format() 이 호출 될 때 설정됩니다.

module

%(module)s

모듈 (filename 의 이름 부분).

msecs

%(msecs)d

LogRecord 가 생성된 시간의 밀리 초 부분.

msg

직접 포맷할 필요는 없습니다.

원래 로깅 호출에서 전달된 포맷 문자열. args 와 병합하여 message 를 만듭니다. 또는 임의의 객체 (임의의 객체를 메시지로 사용하기 를 보세요).

name

%(name)s

로깅 호출에 사용된 로거의 이름.

pathname

%(pathname)s

로깅 호출이 일어난 소스 파일의 전체 경로명 (사용 가능한 경우).

process

%(process)d

프로세스 ID (사용 가능한 경우).

processName

%(processName)s

프로세스 이름 (사용 가능한 경우).

relativeCreated

%(relativeCreated)d

logging 모듈이 로드된 시간을 기준으로 LogRecord가 생성된 시간 (밀리 초).

stack_info

직접 포맷할 필요는 없습니다.

현재 스레드의 스택 바닥에서 이 레코드를 생성한 로깅 호출의 스택 프레임까지의 스택 프레임 정보 (사용 가능한 경우).

thread

%(thread)d

스레드 ID (사용 가능한 경우).

threadName

%(threadName)s

스레드 이름 (사용 가능한 경우).

taskName

%(taskName)s

asyncio.Task name (if available).

버전 3.1에서 변경: processName 이 추가되었습니다.

버전 3.12에서 변경: taskName was added.

LoggerAdapter 객체

LoggerAdapter 인스턴스는 문맥 정보를 로깅 호출에 편리하게 전달하는 데 사용됩니다. 사용 예는, 로그 출력에 문맥 정보 추가 섹션을 참조하십시오.

class logging.LoggerAdapter(logger, extra, merge_extra=False)

Returns an instance of LoggerAdapter initialized with an underlying Logger instance, a dict-like object (extra), and a boolean (merge_extra) indicating whether or not the extra argument of individual log calls should be merged with the LoggerAdapter extra. The default behavior is to ignore the extra argument of individual log calls and only use the one of the LoggerAdapter instance

process(msg, kwargs)

문맥 정보를 삽입하기 위해 로깅 호출에 전달된 메시지 와 키워드 인자를 수정합니다. 이 구현은 생성자에 extra 로 전달된 객체를 가져와서 ‘extra’ 키를 사용하여 kwargs 에 추가합니다. 반환 값은 전달된 인자의 (수정된) 버전을 담은 (msg, kwargs) 튜플입니다.

manager

Delegates to the underlying manager on logger.

_log

Delegates to the underlying _log() method on logger.

위의 것에 더해, LoggerAdapter 는 다음과 같은 Logger 의 메서드를 지원합니다: debug(), info(), warning(), error(), exception(), critical(), log(), isEnabledFor(), getEffectiveLevel(), setLevel(), hasHandlers(). 이 메서드들은 Logger 에 있는 것과 똑같은 서명을 가지므로, 두 형의 인스턴스를 바꿔쓸 수 있습니다.

버전 3.2에서 변경: isEnabledFor(), getEffectiveLevel(), setLevel() 그리고 hasHandlers() 메서드가 LoggerAdapter 에 추가되었습니다. 이 메서드는 하부 로거로 위임합니다.

버전 3.6에서 변경: Attribute manager and method _log() were added, which delegate to the underlying logger and allow adapters to be nested.

버전 3.13에서 변경: The merge_extra argument was added.

스레드 안전성

로깅 모듈은 클라이언트가 특별한 주의를 기울이지 않아도 스레드 안전하도록 만들어졌습니다. 이렇게 하려고 threading 록을 사용합니다; 모듈의 공유 데이터에 대한 액세스를 직렬화하는 록이 하나 있고, 각 처리기 또한 하부 I/O에 대한 액세스를 직렬화하는 록을 만듭니다.

signal 모듈을 사용하여 비동기 시그널 처리기를 구현한다면, 그 처리기 내에서는 logging을 사용할 수 없을 수도 있습니다. 이는 threading 모듈의 록 구현이 언제나 재진입할 수 있지는 않아서 그러한 시그널 처리기에서 호출할 수 없기 때문입니다.

모듈 수준 함수

위에서 설명한 클래스 외에도 많은 모듈 수준 함수가 있습니다.

logging.getLogger(name=None)

Return a logger with the specified name or, if name is None, return the root logger of the hierarchy. If specified, the name is typically a dot-separated hierarchical name like ‘a’, ‘a.b’ or ‘a.b.c.d’. Choice of these names is entirely up to the developer who is using logging, though it is recommended that __name__ be used unless you have a specific reason for not doing that, as mentioned in Logger 객체.

같은 이름으로 이 함수를 여러 번 호출하면 모두 같은 로거 인스턴스를 반환합니다. 이것은 응용 프로그램의 다른 부분 간에 로거 인스턴스를 전달할 필요가 없다는 것을 뜻합니다.

logging.getLoggerClass()

표준 Logger 클래스를 반환하거나, setLoggerClass() 에 전달된 마지막 클래스를 반환합니다. 이 함수는 새 클래스 정의 내에서 호출하여, 사용자 정의 Logger 클래스를 설치할 때 다른 코드가 이미 적용한 사용자 정의를 취소하지 않도록 할 수 있습니다. 예를 들면:

class MyLogger(logging.getLoggerClass()):
    # ... override behaviour here

logging.getLogRecordFactory()

LogRecord 를 생성하는 데 사용되는 콜러블을 반환합니다.

Added in version 3.2: 이 함수는 setLogRecordFactory()와 함께 제공되어, 개발자가 로깅 이벤트를 나타내는 LogRecord 가 만들어지는 방법을 더욱 잘 제어 할 수 있도록 합니다.

팩토리가 어떻게 호출되는지에 대한 더 자세한 정보는 setLogRecordFactory()를 보세요.

logging.debug(msg, *args, **kwargs)

This is a convenience function that calls Logger.debug(), on the root logger. The handling of the arguments is in every way identical to what is described in that method.

The only difference is that if the root logger has no handlers, then basicConfig() is called, prior to calling debug on the root logger.

For very short scripts or quick demonstrations of logging facilities, debug and the other module-level functions may be convenient. However, most programs will want to carefully and explicitly control the logging configuration, and should therefore prefer creating a module-level logger and calling Logger.debug() (or other level-specific methods) on it, as described at the beginning of this documentation.

logging.info(msg, *args, **kwargs)

Logs a message with level INFO on the root logger. The arguments and behavior are otherwise the same as for debug().

logging.warning(msg, *args, **kwargs)

Logs a message with level WARNING on the root logger. The arguments and behavior are otherwise the same as for debug().

참고

기능적으로 warning 와 같은, 구식의 warn 함수가 있습니다. warn 은 폐지되었으므로 사용하지 마십시오 - 대신 warning 을 사용하십시오.

logging.error(msg, *args, **kwargs)

Logs a message with level ERROR on the root logger. The arguments and behavior are otherwise the same as for debug().

logging.critical(msg, *args, **kwargs)

Logs a message with level CRITICAL on the root logger. The arguments and behavior are otherwise the same as for debug().

logging.exception(msg, *args, **kwargs)

Logs a message with level ERROR on the root logger. The arguments and behavior are otherwise the same as for debug(). Exception info is added to the logging message. This function should only be called from an exception handler.

logging.log(level, msg, *args, **kwargs)

Logs a message with level level on the root logger. The arguments and behavior are otherwise the same as for debug().

logging.disable(level=CRITICAL)

모든 로거의 수준을 level 로 오버라이드합니다. 로거 자체 수준보다 우선합니다. 전체 응용 프로그램에서 로깅 출력을 일시적으로 억제해야 할 필요가 생길 때 이 함수가 유용합니다. 그 효과는 심각도 level 및 그 밑의 모든 로깅 호출을 무효화시킵니다. 따라서 INFO 값으로 호출하면 모든 INFO 및 DEBUG 이벤트는 삭제되지만, WARNING 이상의 심각도는 로거의 유효 수준에 따라 처리됩니다. logging.disable(logging.NOTSET) 이 호출되면, 이 오버라이딩 수준을 실질적으로 제거하므로, 로깅 출력은 다시 개별 로거의 유효 수준에 따르게 됩니다.

CRITICAL 보다 더 높은 사용자 정의 로깅 수준을 정의했다면 (권장하지 않습니다), level 매개 변수의 기본값에 의존할 수 없고 적절한 값을 명시적으로 제공해야 합니다.

버전 3.7에서 변경: level 매개 변수의 기본값은 수준 CRITICAL 입니다. 이 변경 사항에 대한 자세한 내용은 bpo-28524 [https://bugs.python.org/issue?@action=redirect&bpo=28524]를 참조하십시오.

logging.addLevelName(level, levelName)

내부 딕셔너리에 수준 level 을 텍스트 levelName 과 연결합니다. 이 딕셔너리는 숫자 수준을 텍스트 표현으로 매핑하는데 (예를 들어, Formatter 가 메시지를 포매팅할 때) 사용됩니다. 이 기능을 사용해서 여러분 자신의 수준을 정의할 수도 있습니다. 제약 조건은, 사용되는 모든 수준이 이 함수를 사용하여 등록되어야 하고, 수준은 양의 정수이어야 하며, 심각도가 높아질수록 값이 커져야 한다는 것입니다.

참고

자신만의 수준을 정의할 생각이라면 사용자 정의 수준 섹션을 보십시오.

logging.getLevelNamesMapping()

Returns a mapping from level names to their corresponding logging levels. For example, the string “CRITICAL” maps to CRITICAL. The returned mapping is copied from an internal mapping on each call to this function.

Added in version 3.11.

logging.getLevelName(level)

로깅 수준 level 의 텍스트 표현을 반환합니다.

level이 미리 정의된 수준 CRITICAL, ERROR, WARNING, INFO 또는 DEBUG 중 하나면 해당 문자열을 얻게 됩니다. addLevelName()을 사용하여 수준과 이름을 연관 지었다면, level 과 연결된 이름이 반환됩니다. 정의된 수준 중 하나에 해당하는 숫자 값이 전달되면, 해당 문자열 표현이 반환됩니다.

level 매개 변수는 ‘INFO’ 와 같은 수준의 문자열 표현도 받아들입니다. 이럴 때, 이 함수는 해당 수준의 숫자 값을 반환합니다.

일치하는 숫자나 문자열 값이 전달되지 않으면, 문자열 ‘Level %s’ % level 이 반환됩니다.

참고

수준은 (로깅 로직에서 비교해야 하므로) 내부적으로 정수입니다. 이 함수는 정수 수준과 %(levelname)s 포맷 지정자(LogRecord 어트리뷰트를 보세요)로 포맷된 로그 출력에 표시된 이름 간의 변환에 사용됩니다.

버전 3.4에서 변경: 3.4 이전의 파이썬 버전에서, 이 함수로 텍스트 수준을 전달할 수 있고, 해당 수준의 숫자 값을 반환합니다. 이 문서로 만들어지지 않은 동작은 실수로 간주하여, 파이썬 3.4에서 제거되었습니다. 하지만 이전 버전과의 호환성을 유지하기 위해 3.4.2에서 복원되었습니다.

logging.getHandlerByName(name)

Returns a handler with the specified name, or None if there is no handler with that name.

Added in version 3.12.

logging.getHandlerNames()

Returns an immutable set of all known handler names.

Added in version 3.12.

logging.makeLogRecord(attrdict)

어트리뷰트가 attrdict 로 정의된 새로운 LogRecord 인스턴스를 만들어서 반환합니다. 이 함수는 피클 된 LogRecord 어트리뷰트 딕셔너리를 소켓으로 보내고, 수신 단에서 LogRecord 인스턴스로 재구성할 때 유용합니다.

logging.basicConfig(**kwargs)

기본 Formatter로 StreamHandler 를 생성하고 루트 로거에 추가하여 로깅 시스템의 기본 구성을 수행합니다. 함수 debug(), info(), warning(), error() 그리고 critical()은 루트 로거에 처리기가 정의되어 있지 않으면 자동으로 basicConfig()를 호출합니다.

이 함수는 루트 로거에 이미 처리기가 구성되어있는 경우, 키워드 인자 force가 True로 설정되지 않는 한, 아무 작업도 수행하지 않습니다.

참고

이 함수는 다른 스레드가 시작되기 전에 메인 스레드에서 호출되어야 합니다. 2.7.1과 3.2 이전의 파이썬 버전에서, 이 함수를 여러 스레드에서 호출하면, (드문 경우지만) 처리기가 두 번 이상 루트 로거에 추가되어, 로그에 메시지가 중복되는 것과 같은 예기치 않은 결과가 발생할 수 있습니다.

다음 키워드 인자가 지원됩니다.

포맷

설명

filename

Specifies that a FileHandler be created, using the specified filename, rather than a StreamHandler.

filemode

filename 이 지정되었으면, 이 모드 로 파일을 엽니다. 기본값은 'a' 입니다.

format

처리기에 지정된 포맷 문자열을 사용합니다. 기본값은 콜론으로 구분된 어트리뷰트 levelname, name 및 message 입니다.

datefmt

time.strftime() 에서 허용하는 방식대로 지정된 날짜/시간 포맷을 사용합니다.

style

format 을 지정하면, 포맷 문자열에 이 스타일을 사용합니다. '%', '{', '$' 중 하나인데 각각 printf 스타일, str.format(), string.Template 에 대응됩니다. 기본값은 '%' 입니다.

level

루트 로거의 수준을 지정된 수준 으로 설정합니다.

stream

Use the specified stream to initialize the StreamHandler. Note that this argument is incompatible with filename - if both are present, a ValueError is raised.

handlers

지정된 경우, 루트 로거에 추가할 이미 만들어진 처리기의 이터러블이어야 합니다. 아직 포매터 세트가 없는 처리기에는 이 함수에서 만들어진 기본 포매터가 지정됩니다. 이 인자는 filename 또는 stream 과 호환되지 않습니다 - 둘 다 있으면 ValueError 가 발생합니다.

force

이 키워드 인자가 참으로 지정되면, 루트 로거에 첨부된 기존 처리기는 다른 인자에 지정된 대로 구성을 수행하기 전에 모두 제거되고 닫힙니다.

encoding

If this keyword argument is specified along with filename, its value is used when the FileHandler is created, and thus used when opening the output file.

errors

If this keyword argument is specified along with filename, its value is used when the FileHandler is created, and thus used when opening the output file. If not specified, the value ‘backslashreplace’ is used. Note that if None is specified, it will be passed as such to open(), which means that it will be treated the same as passing ‘errors’.

버전 3.2에서 변경: style 인자가 추가되었습니다.

버전 3.3에서 변경: handlers 인자가 추가되었습니다. 호환되지 않는 인자(예를 들어, handlers 를 stream 이나 filename 과 함께 쓰거나, stream 을 filename 과 함께 쓰는 경우)가 있는 상황을 파악하기 위한 검사가 추가되었습니다.

버전 3.8에서 변경: force 인자가 추가되었습니다.

버전 3.9에서 변경: encoding과 errors 인자가 추가되었습니다.

logging.shutdown()

로깅 시스템에 모든 처리기를 플러시하고 닫아서 순차적인 종료를 수행하도록 알립니다. 응용 프로그램 종료 시 호출되어야 하고, 이 호출 후에는 로깅 시스템을 더는 사용하지 않아야 합니다.

logging 모듈이 임포트 될 때, 이 함수를 종료 처리기(atexit를 참조하십시오)로 등록하므로, 일반적으로 수동으로 수행할 필요가 없습니다.

logging.setLoggerClass(klass)

Tells the logging system to use the class klass when instantiating a logger. The class should define __init__() such that only a name argument is required, and the __init__() should call Logger.__init__(). This function is typically called before any loggers are instantiated by applications which need to use custom logger behavior. After this call, as at any other time, do not instantiate loggers directly using the subclass: continue to use the logging.getLogger() API to get your loggers.

logging.setLogRecordFactory(factory)

LogRecord 를 만드는데 사용되는 콜러블을 설정합니다.

매개변수:

factory – 로그 레코드의 인스턴스를 만드는데 사용되는 팩토리 콜러블.

Added in version 3.2: 이 함수는 getLogRecordFactory()와 함께 제공되어, 개발자가 로깅 이벤트를 나타내는 LogRecord 가 만들어지는 방법을 더욱 잘 제어 할 수 있도록 합니다.

팩토리의 서명은 다음과 같습니다:

factory(name, level, fn, lno, msg, args, exc_info, func=None, sinfo=None, **kwargs)

name:

로거 이름.

level:

로깅 수준 (숫자).

fn:

로깅 호출이 이루어진 파일의 전체 경로명.

lno:

로깅 호출이 이루어진 파일의 행 번호.

msg:

로깅 메시지

args:

로깅 메시지에 대한 인자.

exc_info:

예외 튜플 또는 None.

func:

로깅 호출을 호출한 함수 또는 메서드의 이름

sinfo:

traceback.print_stack() 가 제공하는 것과 같은 스택 트레이스백. 호출 계층 구조를 보여줍니다.

kwargs:

추가 키워드 인자.

모듈 수준 어트리뷰트

logging.lastResort

“최후 수단 처리기” 는 이 어트리뷰트를 통해 제공됩니다. 이것은 WARNING 수준으로 sys.stderr 에 쓰는 StreamHandler 이고, 로깅 구성이 없을 때 로깅 이벤트를 처리하는 데 사용됩니다. 최종 결과는 sys.stderr 에 메시지를 출력하기만 하는 것입니다. 이것이 예전의 “no handlers could be found for logger XYZ” 라는 에러 메시지를 대체합니다. 어떤 이유로 이전 동작이 필요하면 lastResort 를 None 으로 설정할 수 있습니다.

Added in version 3.2.

logging.raiseExceptions

Used to see if exceptions during handling should be propagated.

Default: True.

If raiseExceptions is False, exceptions get silently ignored. This is what is mostly wanted for a logging system - most users will not care about errors in the logging system, they are more interested in application errors.

warnings 모듈과의 통합

captureWarnings() 함수는 logging을 warnings 모듈과 통합하는데 사용될 수 있습니다.

logging.captureWarnings(capture)

이 함수는 logging 이 경고를 캡처하는 것을 켜고 끄는 데 사용됩니다.

capture 가 True 면, warnings 모듈에 의해 발행된 경고는 로깅 시스템으로 리디렉션됩니다. 특히, 경고는 warnings.formatwarning() 을 사용하여 포맷되고, 결과 문자열을 'py.warnings' 라는 이름의 로거에 심각도 WARNING으로 로그 합니다.

capture 가 False 면, 로깅 시스템으로의 경고 리디렉션은 멈추고, 경고는 원래 목적지(즉, captureWarnings(True) 가 호출되기 전에 적용되던 곳)로 리디렉션됩니다.

더 보기

모듈 logging.config

logging 모듈용 구성 API.

모듈 logging.handlers

logging 모듈에 포함된 유용한 처리기.

PEP 282 [https://peps.python.org/pep-0282/] - 로깅 시스템

파이썬 표준 라이브러리에 포함하기 위해 이 기능을 설명한 제안.

Original Python logging package [https://old.red-dove.com/python_logging.html]

logging 패키지의 원래 소스입니다. 이 사이트에서 제공되는 패키지 버전은 표준 라이브러리에 logging 패키지를 포함하지 않는 파이썬 1.5.2, 2.1.x 및 2.2.x에서 사용하기에 적합합니다.

logging.config — Logging configuration

소스 코드: Lib/logging/config.py [https://github.com/python/cpython/tree/main/Lib/logging/config.py]

Important

이 페이지에는 레퍼런스 정보만 있습니다. 자습서는 다음을 참조하십시오

기초 자습서

고급 자습서

로깅 요리책

이 절에서는 logging 모듈을 구성하기 위한 API에 관해 설명합니다.

구성 함수

다음 함수는 logging 모듈을 구성합니다. logging.config 모듈에 있습니다. 사용은 선택 사항입니다 — 이 함수들을 사용하거나 (logging 자체에서 정의된) 주 API를 호출하고 logging이나 logging.handlers에서 선언된 처리기를 정의해서 logging 모듈을 구성할 수 있습니다.

logging.config.dictConfig(config)

딕셔너리로 로깅 구성을 받습니다. 이 딕셔너리의 내용은 아래의 구성 딕셔너리 스키마에 설명되어 있습니다.

구성 중에 에러를 만나면, 이 함수는 적절하게 설명하는 메시지와 함께 ValueError, TypeError, AttributeError 또는 ImportError를 발생시킵니다. 다음은 에러를 발생시킬 수 있는 (불완전한) 조건 목록입니다:

문자열이 아니거나 실제 로깅 수준과 일치하지 않는 문자열인 level.

불리언이 아닌 propagate 값.

해당 대상이 없는 id.

증분(incremental) 호출 중에 발견된 존재하지 않는 처리기 id.

잘못된 로거 이름.

결정할 수 없는 내부나 외부 객체.

구문 분석은 DictConfigurator 클래스에 의해 수행되며, 생성자로는 구성에 사용되는 딕셔너리가 전달되고, 객체는 configure() 메서드를 가집니다. logging.config 모듈에는 초기에 DictConfigurator로 설정된 콜러블 어트리뷰트 dictConfigClass가 있습니다. 여러분 자신의 적절한 구현으로 dictConfigClass의 값을 바꿀 수 있습니다.

dictConfig()는 dictConfigClass를 호출해서 지정된 딕셔너리를 전달한 다음, 반환된 객체의 configure() 메서드를 호출하여 구성을 적용합니다:

def dictConfig(config):
    dictConfigClass(config).configure()

For example, a subclass of DictConfigurator could call DictConfigurator.__init__() in its own __init__(), then set up custom prefixes which would be usable in the subsequent configure() call. dictConfigClass would be bound to this new subclass, and then dictConfig() could be called exactly as in the default, uncustomized state.

Added in version 3.2.

logging.config.fileConfig(fname, defaults=None, disable_existing_loggers=True, encoding=None)

configparser-형식 파일에서 로깅 구성을 읽습니다. 파일 형식은 구성 파일 형식에 설명된 것과 같아야 합니다. 이 함수는 응용 프로그램에서 여러 번 호출 할 수 있어서, 최종 사용자가 여러 가지 미리 준비된 구성 중에서 선택할 수 있도록 합니다 (개발자가 선택 사항을 표시하고 선택한 구성을 로드하는 메커니즘을 제공한다면).

It will raise FileNotFoundError if the file doesn’t exist and RuntimeError if the file is invalid or empty.

매개변수:

fname – A filename, or a file-like object, or an instance derived from RawConfigParser. If a RawConfigParser-derived instance is passed, it is used as is. Otherwise, a ConfigParser is instantiated, and the configuration read by it from the object passed in fname. If that has a readline() method, it is assumed to be a file-like object and read using read_file(); otherwise, it is assumed to be a filename and passed to read().

defaults – Defaults to be passed to the ConfigParser can be specified in this argument.

disable_existing_loggers – False로 지정되면, 이 호출이 이루어졌을 때 존재하는 로거는 활성화된 상태로 남습니다. 기본값은 True이므로, 과거 호환성을 유지하도록 이전 동작을 활성화합니다. 이 동작은 이미 존재하는 비 루트 로거를 그들이나 그들의 조상이 로깅 구성에서 명시적으로 명명되지 않으면 비활성화하는 것입니다.

encoding – The encoding used to open file when fname is filename.

버전 3.4에서 변경: An instance of a subclass of RawConfigParser is now accepted as a value for fname. This facilitates:

로깅 구성이 전체 응용 프로그램 구성의 일부인 구성 파일의 사용.

파일에서 읽어 들인 다음 fileConfig로 전달되기 전에 사용하는 응용 프로그램이 (예를 들어, 명령 줄 매개 변수나 실행 시간 환경의 다른 측면에 기반하여) 수정하는 구성의 사용.

버전 3.10에서 변경: Added the encoding parameter.

버전 3.12에서 변경: An exception will be thrown if the provided file doesn’t exist or is invalid or empty.

logging.config.listen(port=DEFAULT_LOGGING_CONFIG_PORT, verify=None)

지정된 포트에서 소켓 서버를 시작하고, 새 구성을 수신 대기합니다. 포트를 지정하지 않으면, 모듈의 기본 DEFAULT_LOGGING_CONFIG_PORT가 사용됩니다. 로깅 구성은 dictConfig()나 fileConfig()로 처리하기에 적합한 파일로 전송됩니다. 서버를 시작하기 위해 start()를 호출할 수 있는 Thread 인스턴스를 반환하고, 적절할 때 join()할 수 있습니다. 서버를 중지하려면, stopListening()을 호출하십시오.

verify 인자가 지정되면, 소켓을 통해 수신된 바이트열이 유효하고 처리되어야 하는지를 확인하는 콜러블이어야 합니다. 소켓을 통해 전송되는 것을 암호화 및/또는 서명하고, verify 콜러블이 서명 확인 및/또는 암호 해독을 수행할 수 있습니다. verify 콜러블은 단일 인자(소켓을 통해 수신된 바이트열)로 호출되며, 처리할 바이트열이나 바이트열을 버려야 함을 나타내기 위해 None을 반환합니다. 반환된 바이트열은 전달된 바이트열과 같을 수 있고 (예를 들어, 확인만 수행될 때), 또는 완전히 다를 수 있습니다 (아마도 암호 해독이 수행될 때).

소켓으로 구성을 보내려면, 구성 파일을 읽어서 소켓에 struct.pack('>L', n)를 사용하여 바이너리로 만든 4바이트의 길이를 앞에 붙인 바이트 시퀀스를 보냅니다.

참고

Because portions of the configuration are passed through eval(), use of this function may open its users to a security risk. While the function only binds to a socket on localhost, and so does not accept connections from remote machines, there are scenarios where untrusted code could be run under the account of the process which calls listen(). Specifically, if the process calling listen() runs on a multi-user machine where users cannot trust each other, then a malicious user could arrange to run essentially arbitrary code in a victim user’s process, simply by connecting to the victim’s listen() socket and sending a configuration which runs whatever code the attacker wants to have executed in the victim’s process. This is especially easy to do if the default port is used, but not hard even if a different port is used. To avoid the risk of this happening, use the verify argument to listen() to prevent unrecognised configurations from being applied.

버전 3.4에서 변경: verify 인자가 추가되었습니다.

참고

리스너에 기존 로거를 비활성화하지 않는 구성을 보내려면, dictConfig()를 사용하도록 구성에 JSON 형식을 사용해야 합니다. 이 방법은 보내는 구성에서 disable_existing_loggers를 False로 지정할 수 있도록 합니다.

logging.config.stopListening()

listen()에 대한 호출로 만들어진 리스닝 서버를 중지합니다. 이것은 일반적으로 listen()의 반환 값에 대해 join()을 호출하기 전에 호출됩니다.

Security considerations

The logging configuration functionality tries to offer convenience, and in part this is done by offering the ability to convert text in configuration files into Python objects used in logging configuration - for example, as described in 사용자 정의 객체. However, these same mechanisms (importing callables from user-defined modules and calling them with parameters from the configuration) could be used to invoke any code you like, and for this reason you should treat configuration files from untrusted sources with extreme caution and satisfy yourself that nothing bad can happen if you load them, before actually loading them.

구성 딕셔너리 스키마

로깅 구성을 기술하려면 만들려는 다양한 객체와 그들 간의 연결을 나열해야 합니다; 예를 들어, ‘console’이라는 처리기를 만든 다음 ‘startup’이라는 로거가 ‘console’ 처리기에 메시지를 보낼 것이라고 말할 수 있습니다. 사용자 자신의 포매터나 처리기 클래스를 작성할 수 있으므로, 이러한 객체가 logging 모듈에서 제공하는 객체로만 제한되지는 않습니다. 이러한 클래스의 매개 변수는 sys.stderr과 같은 외부 객체를 포함할 수도 있습니다. 이러한 객체와 연결을 기술하는 문법은 아래의 객체 연결에 정의되어 있습니다.

딕셔너리 스키마 세부사항

dictConfig()에 전달되는 딕셔너리에는 반드시 다음 키가 있어야 합니다:

version - 스키마 버전을 나타내는 정숫값으로 설정됩니다. 현재 유효한 유일한 값은 1이지만, 이 키를 사용하면 과거 호환성을 유지하면서 스키마를 발전시킬 수 있습니다.

다른 모든 키는 선택 사항이지만, 있으면 아래에 설명된 대로 해석됩니다. 아래에서 ‘구성 딕셔너리(configuring dict)’가 언급되는 모든 경우에, 특수한 '()' 키를 검사해서 사용자 정의 인스턴스화가 필요한지를 확인합니다. 있다면, 아래의 사용자 정의 객체에 설명된 메커니즘을 사용하여 인스턴스를 만듭니다; 그렇지 않다면, 어떤 인스턴스를 만들지를 결정하는데 문맥이 사용됩니다.

formatters - 해당 값은 딕셔너리인데, 각 키는 포매터 id이고, 각 값은 해당 Formatter 인스턴스를 구성하는 방법을 설명하는 딕셔너리입니다.

The configuring dict is searched for the following optional keys which correspond to the arguments passed to create a Formatter object:

format

datefmt

style

validate (since version >=3.8)

defaults (since version >=3.12)

An optional class key indicates the name of the formatter’s class (as a dotted module and class name). The instantiation arguments are as for Formatter, thus this key is most useful for instantiating a customised subclass of Formatter. For example, the alternative class might present exception tracebacks in an expanded or condensed format. If your formatter requires different or extra configuration keys, you should use 사용자 정의 객체.

filters - 해당 값은 딕셔너리인데, 각 키가 필터 id이고 각 값은 해당 Filter 인스턴스를 구성하는 방법을 설명하는 딕셔너리입니다.

구성 딕셔너리는 키 name(기본값은 빈 문자열)으로 검색되며, 이는 logging.Filter 인스턴스를 만드는 데 사용됩니다.

handlers - 해당 값은 딕셔너리인데, 각 키가 처리기 id이고 각 값은 해당 Handler 인스턴스를 구성하는 방법을 설명하는 딕셔너리입니다.

구성 딕셔너리는 다음 키에서 검색합니다:

class (필수). 이것은 처리기 클래스의 완전히 정규화된 이름입니다.

level (선택). 처리기의 수준.

formatter (선택). 이 처리기의 포매터의 id.

filters (선택). 이 처리기의 필터의 id의 리스트.

버전 3.11에서 변경: filters can take filter instances in addition to ids.

모든 다른 키는, 처리기의 생성자에 키워드 인자로 전달됩니다. 예를 들어, 다음과 같이 주어진 조각에서:

handlers:
  console:
    class : logging.StreamHandler
    formatter: brief
    level   : INFO
    filters: [allow_foo]
    stream  : ext://sys.stdout
  file:
    class : logging.handlers.RotatingFileHandler
    formatter: precise
    filename: logconfig.log
    maxBytes: 1024
    backupCount: 3

id가 console 인 처리기는 sys.stdout를 하부 스트림으로 사용하는 logging.StreamHandler로 인스턴스가 만들어집니다. id가 file 인 처리기는 키워드 인자 filename='logconfig.log', maxBytes=1024, backupCount=3를 사용하여 logging.handlers.RotatingFileHandler로 인스턴스가 만들어집니다.

loggers - 해당 값은 딕셔너리인데, 각 키가 로거 이름이고 각 값은 해당 Logger 인스턴스를 구성하는 방법을 설명하는 딕셔너리입니다.

구성 딕셔너리는 다음 키에서 검색합니다:

level (선택). 로거의 수준.

propagate (선택). 로거의 전파(propagation) 설정.

filters (선택). 이 로거의 필터의 id의 리스트

버전 3.11에서 변경: filters can take filter instances in addition to ids.

handlers (선택). 이 로거의 처리기의 id의 리스트.

지정된 로거는 지정된 수준, 전파, 필터와 처리기에 따라 구성됩니다.

root - 루트 로거에 대한 구성입니다. propagate 설정을 적용할 수 없다는 점을 제외하고 구성 처리는 모든 로거와 같습니다.

incremental - 구성을 기존 구성의 증분으로 해석할지 여부. 이 값의 기본값은 False이며, 이는 지정된 구성이 기존 구성을 기존 fileConfig() API에서 사용된 것과 같은 의미로 대체 함을 뜻합니다.

지정된 값이 True이면, 증분 구성 절에서 설명하는 대로 구성이 처리됩니다.

disable_existing_loggers - 기존의 루트가 아닌 로거를 비활성화할지 여부. 이 설정은 fileConfig()의 같은 이름의 매개 변수를 반영합니다. 없으면, 이 매개 변수의 기본값은 True입니다. incremental이 True이면 이 값은 무시됩니다.

증분 구성

증분 구성에 완벽한 유연성을 제공하기는 어렵습니다. 예를 들어, 필터와 포매터와 같은 객체는 익명이므로, 일단 구성이 설정되면, 이러한 익명 객체를 참조하여 구성을 보강할 수 없습니다.

또한, 일단 구성이 설정되면, 실행 시간에 로거, 처리기, 필터, 포매터의 객체 그래프를 임의로 변경해야 할 강력한 사례는 없습니다; 로거와 처리기의 상세도는 단지 수준(과, loggers에서는 전파 플래그)을 설정하여 제어할 수 있습니다. 객체 그래프를 임의로 안전하게 변경하는 것은 다중 스레드 환경에서 문제가 됩니다; 불가능하지는 않지만, 구현에 추가되는 복잡성을 상쇄할만한 가치가 없습니다.

따라서, 구성 딕셔너리의 incremental 키가 있고 True이면, 시스템은 formatters와 filters 항목을 완전히 무시하고 handlers 항목의 level 설정과 loggers와 root 항목의 level과 propagate 설정만 처리합니다.

구성 딕셔너리의 값을 사용하면 구성을 피클 된 딕셔너리의 형태로 네트워크를 통해 소켓 리스너로 전송할 수 있습니다. 따라서, 장기 실행 응용 프로그램의 로깅 상세도는 응용 프로그램을 중지하고 다시 시작할 필요 없이 도중에 변경될 수 있습니다.

객체 연결

스키마는 객체 그래프에서 서로 연결된 로깅 객체 집합(로거, 처리기, 포매터, 필터)을 기술합니다. 따라서, 스키마는 객체 간의 연결을 표현할 필요가 있습니다. 예를 들어, 일단 구성되면, 특정 로거가 특정 처리기에 연결된다고 합시다. 이 토론의 목적을 위해, 둘 간의 연결에서 로거는 소스를, 처리기는 대상(destination)을 나타낸다고 할 수 있습니다. 물론 구성된 객체에서 이것은 처리기에 대한 참조를 갖는 로거로 표현됩니다. 구성 딕셔너리에서, 각 대상 객체에 명확하게 식별하는 id를 부여한 다음, 소스 객체의 구성에서 그 id를 사용하여, 소스와 그 id를 갖는 대상 객체 사이에 연결이 있음을 나타냅니다.

그래서, 예를 들어, 다음 YAML 조각을 고려해보십시오:

formatters:
  brief:
    # configuration for formatter with id 'brief' goes here
  precise:
    # configuration for formatter with id 'precise' goes here
handlers:
  h1: #This is an id
   # configuration of handler with id 'h1' goes here
   formatter: brief
  h2: #This is another id
   # configuration of handler with id 'h2' goes here
   formatter: precise
loggers:
  foo.bar.baz:
    # other configuration for logger 'foo.bar.baz'
    handlers: [h1, h2]

(참고: 딕셔너리에 해당하는 파이썬 소스 형식보다 약간 더 읽기 쉬우므로 여기에서 YAML을 사용했습니다.)

로거의 id는 로거로의 참조를 얻기 위해서 프로그램적으로 사용되는 로거 이름입니다, 예를 들어 foo.bar.baz. 포매터와 필터의 id는 임의의 문자열 값(가령 위의 brief, precise)이 될 수 있으며, 일시적이므로 구성 딕셔너리 처리에만 의미가 있고 객체 간의 연결을 결정하는 데 사용되며, 구성 호출이 완료된 후에는 어디에도 남아있지 않습니다.

위의 조각은 foo.bar.baz라는 로거에 두 개의 처리기가 연결되어 있어야 하며, 이 처리기들은 처리기 id h1과 h2에 의해 기술됩니다. h1의 포매터는 id brief로 기술되는 것이고, h2의 포매터는 id precise로 기술되는 것입니다.

사용자 정의 객체

스키마는 처리기, 필터 및 포매터에 대한 사용자 정의 객체를 지원합니다. (로거에는 인스턴스마다 다른 형이 필요하지 않으므로, 이 구성 스키마에는 사용자 정의 로거 클래스에 대한 지원이 없습니다.)

구성할 객체는 구성을 자세히 설명하는 딕셔너리로 시술됩니다. 어떤 곳에서는, 로깅 시스템이 객체를 어떻게 인스턴스화할지 문맥으로부터 추측할 수 있지만, 사용자 정의 객체를 인스턴스화 해야 할 때, 시스템은 이를 수행하는 방법을 알 수 없습니다. 사용자 정의 객체 인스턴스화를 위한 완벽한 유연성을 제공하기 위해, 사용자는 ‘팩토리’를 제공해야 하는데, 구성 딕셔너리로 호출되고 인스턴스화 된 객체를 반환하는 콜러블입니다. 이것은 특수키 '()'로 제공되는 팩토리로의 절대적 임포트 경로로 표시됩니다. 다음은 구체적인 예입니다:

formatters:
  brief:
    format: '%(message)s'
  default:
    format: '%(asctime)s %(levelname)-8s %(name)-15s %(message)s'
    datefmt: '%Y-%m-%d %H:%M:%S'
  custom:
      (): my.package.customFormatterFactory
      bar: baz
      spam: 99.9
      answer: 42

위의 YAML 조각은 세 가지 포매터를 정의합니다. 첫 번째(id brief)는 지정된 포맷 문자열을 갖는 표준 logging.Formatter 인스턴스입니다. 두 번째(id default)는 더 긴 포맷을 가지며 명시적으로 시간 포맷을 정의하기도 하고, 이 두 포맷 문자열로 초기화된 logging.Formatter가 됩니다. 파이썬 소스 형식으로 표시하면, brief와 default 포매터는 각각 다음과 같은 구성 서브 딕셔너리를 갖습니다:

{
  'format' : '%(message)s'
}

그리고:

{
  'format' : '%(asctime)s %(levelname)-8s %(name)-15s %(message)s',
  'datefmt' : '%Y-%m-%d %H:%M:%S'
}

그리고, 이 딕셔너리에는 특수키 '()'가 포함되어 있지 않으므로, 문맥에서 인스턴스가 추론됩니다: 결과적으로, 표준 logging.Formatter 인스턴스가 만들어집니다. 세 번째 포매터(id custom)에 대한 구성 서브 딕셔너리는 다음과 같습니다:

{
  '()' : 'my.package.customFormatterFactory',
  'bar' : 'baz',
  'spam' : 99.9,
  'answer' : 42
}

여기에는 특수키 '()'가 포함되어 있는데, 사용자 정의 인스턴스가 필요하다는 뜻입니다. 이때, 지정된 팩토리 콜러블이 사용됩니다. 그것이 실제 콜러블이면 직접 사용됩니다 - 그렇지 않고, (예에서와같이) 문자열을 지정하면 일반적인 임포트 메커니즘을 사용하여 실제 콜러블을 얻습니다. 콜러블은 구성 서브 딕셔너리의 나머지 항목을 키워드 인자로 호출됩니다. 위의 예제에서, id가 custom인 포매터는 다음과 같은 호출이 반환한다고 가정합니다:

my.package.customFormatterFactory(bar='baz', spam=99.9, answer=42)

경고

The values for keys such as bar, spam and answer in the above example should not be configuration dictionaries or references such as cfg://foo or ext://bar, because they will not be processed by the configuration machinery, but passed to the callable as-is.

'()' 키가 유효한 키워드 매개 변수 이름이 아니라서 특수키로 사용되었습니다. 그러므로 호출에 사용되는 키워드 인자의 이름과 충돌하지 않습니다. '()'는 해당 값이 콜러블이라는 표시로도 기능합니다.

버전 3.11에서 변경: The filters member of handlers and loggers can take filter instances in addition to ids.

You can also specify a special key '.' whose value is a dictionary is a mapping of attribute names to values. If found, the specified attributes will be set on the user-defined object before it is returned. Thus, with the following configuration:

{
  '()' : 'my.package.customFormatterFactory',
  'bar' : 'baz',
  'spam' : 99.9,
  'answer' : 42,
  '.' {
    'foo': 'bar',
    'baz': 'bozz'
  }
}

the returned formatter will have attribute foo set to 'bar' and attribute baz set to 'bozz'.

경고

The values for attributes such as foo and baz in the above example should not be configuration dictionaries or references such as cfg://foo or ext://bar, because they will not be processed by the configuration machinery, but set as attribute values as-is.

Handler configuration order

Handlers are configured in alphabetical order of their keys, and a configured handler replaces the configuration dictionary in (a working copy of) the handlers dictionary in the schema. If you use a construct such as cfg://handlers.foo, then initially handlers['foo'] points to the configuration dictionary for the handler named foo, and later (once that handler has been configured) it points to the configured handler instance. Thus, cfg://handlers.foo could resolve to either a dictionary or a handler instance. In general, it is wise to name handlers in a way such that dependent handlers are configured _after_ any handlers they depend on; that allows something like cfg://handlers.foo to be used in configuring a handler that depends on handler foo. If that dependent handler were named bar, problems would result, because the configuration of bar would be attempted before that of foo, and foo would not yet have been configured. However, if the dependent handler were named foobar, it would be configured after foo, with the result that cfg://handlers.foo would resolve to configured handler foo, and not its configuration dictionary.

외부 객체에 대한 액세스

구성에서 구성 외부의 객체를 참조해야 하는 경우가 있습니다, 예를 들어 sys.stderr. 구성 딕셔너리가 파이썬 코드를 사용하여 만들어질 때는 간단하지만, 구성이 텍스트 파일(예를 들어, JSON, YAML)을 통해 제공될 때 문제가 발생합니다. 텍스트 파일에서는, sys.stderr를 리터럴 문자열 'sys.stderr'과 구별하는 표준 방법이 없습니다. 이 구별을 쉽게 하기 위해, 구성 시스템은 문자열 값에서 특정 접두사를 찾아 특수하게 처리합니다. 예를 들어, 리터럴 문자열 'ext://sys.stderr'이 구성에서 값으로 제공되면, ext://는 제거되고 값의 나머지 부분을 일반 임포트 메커니즘을 사용하여 처리합니다.

이러한 접두사의 처리는 프로토콜 처리와 유사한 방식으로 수행됩니다: 정규식 ^(?P<prefix>[a-z]+)://(?P<suffix>.*)$와 일치하는 접두사를 찾는 일반 메커니즘이 있습니다. prefix가 인식되면 suffix는 접두사 종속적 방식으로 처리되고 처리 결과가 문자열 값을 대체합니다. 접두사가 인식되지 않으면, 문자열 값은 그대로 남습니다.

내부 객체에 대한 액세스

외부 객체뿐만 아니라, 때로 구성에 있는 객체를 참조할 필요도 있습니다. 이것은 구성 시스템이 알고 있는 것들에 대해 묵시적으로 수행됩니다. 예를 들어, 로거나 처리기의 level에 대한 문자열 값 'DEBUG'은 자동으로 값 logging.DEBUG으로 변환되고, handlers, filters 및 formatter 항목은 객체 id를 받아서 적절한 대상 객체로 결정합니다.

하지만, logging 모듈에 알려지지 않은 사용자 정의 객체에는 더욱 일반적인 메커니즘이 필요합니다. 예를 들어, 위임할 다른 처리기인 target 인자를 취하는 logging.handlers.MemoryHandler를 고려해봅시다. 시스템이 이미 이 클래스에 대해 알고 있으므로, 구성에서, 주어진 target은 단지 관련 target 처리기의 객체 id이기만 하면 되며, 시스템은 id로부터 처리기를 결정합니다. 그러나 사용자가 alternate 처리기를 갖는 my.package.MyHandler를 정의하면, 구성 시스템은 alternate가 처리기를 참조한다는 것을 알 수 없습니다. 이 문제를 해결하기 위해, 일반 결정 시스템은 사용자가 다음과 같이 지정할 수 있게 합니다:

handlers:
  file:
    # configuration of file handler goes here

  custom:
    (): my.package.MyHandler
    alternate: cfg://handlers.file

리터럴 문자열 'cfg://handlers.file'은 ext:// 접두사가 있는 문자열과 비슷하게 결정되지만, 임포트 이름 공간이 아닌 구성 자체를 조회합니다. 이 메커니즘은 str.format에서 제공하는 것과 유사한 방식으로 점이나 인덱스로 액세스하는 것을 허락합니다. 따라서, 구성에서 다음과 같은 조각이 주어질 때:

handlers:
  email:
    class: logging.handlers.SMTPHandler
    mailhost: localhost
    fromaddr: my_app@domain.tld
    toaddrs:
      - support_team@domain.tld
      - dev_team@domain.tld
    subject: Houston, we have a problem.

in the configuration, the string 'cfg://handlers' would resolve to the dict with key handlers, the string 'cfg://handlers.email would resolve to the dict with key email in the handlers dict, and so on. The string 'cfg://handlers.email.toaddrs[1] would resolve to 'dev_team@domain.tld' and the string 'cfg://handlers.email.toaddrs[0]' would resolve to the value 'support_team@domain.tld'. The subject value could be accessed using either 'cfg://handlers.email.subject' or, equivalently, 'cfg://handlers.email[subject]'. The latter form only needs to be used if the key contains spaces or non-alphanumeric characters. Please note that the characters [ and ] are not allowed in the keys. If an index value consists only of decimal digits, access will be attempted using the corresponding integer value, falling back to the string value if needed.

문자열 cfg://handlers.myhandler.mykey.123이 주어지면, config_dict['handlers']['myhandler']['mykey']['123']으로 변환됩니다. 문자열이 cfg://handlers.myhandler.mykey[123]로 지정되면, 시스템은 config_dict['handlers']['myhandler']['mykey'][123]에서 값을 가져오려고 시도하고, 실패하면 config_dict['handlers']['myhandler']['mykey']['123']으로 폴백합니다.

임포트 결정과 사용자 정의 임포터

임포트 결정은, 기본적으로, 임포트 하는데 내장 __import__() 함수를 사용합니다. 이것을 자신의 임포트 메커니즘으로 바꾸고 싶을 수 있습니다: 그렇다면, DictConfigurator나 그것의 슈퍼 클래스(BaseConfigurator 클래스)의 importer 어트리뷰트를 바꿀 수 있습니다. 그러나, 함수가 클래스에서 디스크립터를 통해 액세스 되는 방식 때문에 주의해야 합니다. 파이썬 콜러블을 사용하여 임포트를 수행하려고 하고, 인스턴스 수준이 아닌 클래스 수준에서 정의하려고 한다면, staticmethod()로 감쌀 필요가 있습니다. 예를 들면:

from importlib import import_module
from logging.config import BaseConfigurator

BaseConfigurator.importer = staticmethod(import_module)

구성자 instance에서 임포트 콜러블을 설정한다면, staticmethod()로 감쌀 필요가 없습니다.

Configuring QueueHandler and QueueListener

If you want to configure a QueueHandler, noting that this is normally used in conjunction with a QueueListener, you can configure both together. After the configuration, the QueueListener instance will be available as the listener attribute of the created handler, and that in turn will be available to you using getHandlerByName() and passing the name you have used for the QueueHandler in your configuration. The dictionary schema for configuring the pair is shown in the example YAML snippet below.

handlers:
  qhand:
    class: logging.handlers.QueueHandler
    queue: my.module.queue_factory
    listener: my.package.CustomListener
    handlers:
      - hand_name_1
      - hand_name_2
      ...

The queue and listener keys are optional.

If the queue key is present, the corresponding value can be one of the following:

An object implementing the Queue.put_nowait and Queue.get public API. For instance, this may be an actual instance of queue.Queue or a subclass thereof, or a proxy obtained by multiprocessing.managers.SyncManager.Queue().

This is of course only possible if you are constructing or modifying the configuration dictionary in code.

A string that resolves to a callable which, when called with no arguments, returns the queue instance to use. That callable could be a queue.Queue subclass or a function which returns a suitable queue instance, such as my.module.queue_factory().

A dict with a '()' key which is constructed in the usual way as discussed in 사용자 정의 객체. The result of this construction should be a queue.Queue instance.

If the queue key is absent, a standard unbounded queue.Queue instance is created and used.

If the listener key is present, the corresponding value can be one of the following:

A subclass of logging.handlers.QueueListener. This is of course only possible if you are constructing or modifying the configuration dictionary in code.

A string which resolves to a class which is a subclass of QueueListener, such as 'my.package.CustomListener'.

A dict with a '()' key which is constructed in the usual way as discussed in 사용자 정의 객체. The result of this construction should be a callable with the same signature as the QueueListener initializer.

If the listener key is absent, logging.handlers.QueueListener is used.

The values under the handlers key are the names of other handlers in the configuration (not shown in the above snippet) which will be passed to the queue listener.

Any custom queue handler and listener classes will need to be defined with the same initialization signatures as QueueHandler and QueueListener.

Added in version 3.12.

구성 파일 형식

fileConfig()이 이해하는 구성 파일 형식은 configparser 기능을 기반으로 합니다. 파일에는 [loggers], [handlers] 및 [formatters]라는 섹션이 있어야 하며, 이 섹션에서는 파일에 정의된 각 유형의 엔티티를 이름으로 식별합니다. 이러한 엔티티마다 해당 엔티티 구성 방법을 식별하는 별도의 섹션이 있습니다. 따라서, [loggers] 섹션에서 log01이라고 이름 붙은 로거에 대해, 관련 구성 세부 사항은 [logger_log01] 섹션에 담깁니다. 마찬가지로, [handlers] 섹션에서 hand01이라고 부르는 처리기는 [handler_hand01]이라는 섹션에 구성이 담기고, [formatters] 섹션에서 form01이라고 부르는 포매터는 [formatter_form01]이라는 섹션에서 구성이 지정됩니다. 루트 로거 구성은 [logger_root]라는 섹션에서 지정해야 합니다.

참고

fileConfig() API는 dictConfig() API보다 오래되었으며 로깅의 특정 측면을 다루는 기능을 제공하지 않습니다. 예를 들어, fileConfig()를 사용해서는 간단한 정수 수준을 넘어서는 메시지 필터링을 제공하는 Filter 객체를 구성할 수 없습니다. 로깅 구성에 Filter 인스턴스가 필요하면, dictConfig()를 사용해야 합니다. 향후 구성 기능의 개선은 dictConfig()에 추가될 것임에 유의하십시오. 따라서, 편리할 때 이 새로운 API로 전환하는 것을 고려해 볼 가치가 있습니다.

파일에 있는 이 절의 예는 아래에 나와 있습니다.

[loggers]
keys=root,log02,log03,log04,log05,log06,log07

[handlers]
keys=hand01,hand02,hand03,hand04,hand05,hand06,hand07,hand08,hand09

[formatters]
keys=form01,form02,form03,form04,form05,form06,form07,form08,form09

루트 로거는 수준과 처리기 목록을 지정해야 합니다. 루트 로거 섹션의 예가 아래에 나와 있습니다.

[logger_root]
level=NOTSET
handlers=hand01

The level entry can be one of DEBUG, INFO, WARNING, ERROR, CRITICAL or NOTSET. For the root logger only, NOTSET means that all messages will be logged. Level values are evaluated in the context of the logging package’s namespace.

handlers 항목은 [handlers] 섹션에 나타나야 하는 처리기 이름의 쉼표로 구분된 목록입니다. 이 이름들은 [handlers] 섹션에 나타나야 하며, 구성 파일에 해당 섹션이 있어야 합니다.

루트 로거가 아닌 로거의 경우, 몇 가지 추가 정보가 필요합니다. 이것은 다음 예제가 보여줍니다.

[logger_parser]
level=DEBUG
handlers=hand01
propagate=1
qualname=compiler.parser

level과 handlers 항목은 루트 로거에서처럼 해석됩니다. 단, 루트가 아닌 로거의 수준이 NOTSET로 지정되면, 시스템은 로거의 유효 수준을 판별하기 위해 상위 계층 로거를 참조합니다. propagate 항목은 메시지가 이 로거로부터 더 높은 로거 계층의 처리기로 전파되어야 함을 나타내려면 1로 설정되고, 메시지가 계층 위의 처리기로 전달되지 않음을 나타내려면 0으로 설정됩니다. qualname 항목은 로거의 계층적 채널 이름, 즉 응용 프로그램에서 로거를 가져오는 데 사용되는 이름입니다.

처리기 구성을 지정하는 섹션은 다음과 같이 예시됩니다.

[handler_hand01]
class=StreamHandler
level=NOTSET
formatter=form01
args=(sys.stdout,)

class 항목은 (logging 패키지의 이름 공간에서 eval()로 결정되는) 처리기의 클래스를 나타냅니다. level은 로거에서처럼 해석되며, NOTSET은 ‘모든 것을 로깅’을 의미합니다.

formatter 항목은 이 처리기의 포매터의 키 이름을 나타냅니다. 비어 있으면, 기본 포매터(logging._defaultFormatter)가 사용됩니다. 이름이 지정되면, [formatters] 섹션에 나타나야 하며 구성 파일에 해당 섹션이 있어야 합니다.

The args entry, when evaluated in the context of the logging package’s namespace, is the list of arguments to the constructor for the handler class. Refer to the constructors for the relevant handlers, or to the examples below, to see how typical entries are constructed. If not provided, it defaults to ().

The optional kwargs entry, when evaluated in the context of the logging package’s namespace, is the keyword argument dict to the constructor for the handler class. If not provided, it defaults to {}.

[handler_hand02]
class=FileHandler
level=DEBUG
formatter=form02
args=('python.log', 'w')

[handler_hand03]
class=handlers.SocketHandler
level=INFO
formatter=form03
args=('localhost', handlers.DEFAULT_TCP_LOGGING_PORT)

[handler_hand04]
class=handlers.DatagramHandler
level=WARN
formatter=form04
args=('localhost', handlers.DEFAULT_UDP_LOGGING_PORT)

[handler_hand05]
class=handlers.SysLogHandler
level=ERROR
formatter=form05
args=(('localhost', handlers.SYSLOG_UDP_PORT), handlers.SysLogHandler.LOG_USER)

[handler_hand06]
class=handlers.NTEventLogHandler
level=CRITICAL
formatter=form06
args=('Python Application', '', 'Application')

[handler_hand07]
class=handlers.SMTPHandler
level=WARN
formatter=form07
args=('localhost', 'from@abc', ['user1@abc', 'user2@xyz'], 'Logger Subject')
kwargs={'timeout': 10.0}

[handler_hand08]
class=handlers.MemoryHandler
level=NOTSET
formatter=form08
target=
args=(10, ERROR)

[handler_hand09]
class=handlers.HTTPHandler
level=NOTSET
formatter=form09
args=('localhost:9022', '/log', 'GET')
kwargs={'secure': True}

포매터 구성을 지정하는 섹션은 다음과 같이 예시됩니다.

[formatter_form01]
format=F1 %(asctime)s %(levelname)s %(message)s %(customfield)s
datefmt=
style=%
validate=True
defaults={'customfield': 'defaultvalue'}
class=logging.Formatter

The arguments for the formatter configuration are the same as the keys in the dictionary schema formatters section.

The defaults entry, when evaluated in the context of the logging package’s namespace, is a dictionary of default values for custom formatting fields. If not provided, it defaults to None.

참고

위에서 설명한 대로 eval()를 사용하기 때문에, listen()을 사용하여 소켓을 통해 구성을 보내고 받을 때 발생할 수 있는 잠재적인 보안 위험이 있습니다. 위험은 상호 신뢰가 없는 여러 사용자가 같은 기계에서 코드를 실행할 때로 제한됩니다; 자세한 내용은 listen() 설명서를 참조하십시오.

더 보기

모듈 logging

logging 모듈에 관한 API 레퍼런스.

모듈 logging.handlers

logging 모듈에 포함된 유용한 처리기.

logging.handlers — Logging handlers

소스 코드: Lib/logging/handlers.py [https://github.com/python/cpython/tree/main/Lib/logging/handlers.py]

Important

이 페이지에는 레퍼런스 정보만 있습니다. 자습서는 다음을 참조하십시오

기초 자습서

고급 자습서

로깅 요리책

다음과 같은 유용한 처리기가 패키지에서 제공됩니다. 3개의 처리기(StreamHandler, FileHandler, NullHandler)는 실제로는 logging 모듈 자체에 정의되어 있지만, 다른 처리기들과 함께 여기에서 설명합니다.

StreamHandler

핵심 logging 패키지에 있는 StreamHandler 클래스는 sys.stdout, sys.stderr 또는 임의의 파일류 객체(또는 더 정확하게, write()와 flush() 메서드를 지원하는 모든 객체)와 같은 스트림으로 로깅 출력을 보냅니다.

class logging.StreamHandler(stream=None)

StreamHandler 클래스의 새로운 인스턴스를 반환합니다. stream 이 지정되면, 인스턴스는 그것을 로그 출력용으로 사용합니다; 그렇지 않으면, sys.stderr 이 사용됩니다.

emit(record)

포매터가 지정되면, 레코드를 포맷하는 데 사용됩니다. 그런 다음 레코드는 terminator를 붙여 스트림에 기록됩니다. 예외 정보가 있으면, traceback.print_exception()을 사용하여 포맷한 후 스트림에 덧붙입니다.

flush()

스트림의 flush() 메서드를 호출해서 플러시 합니다. close() 메서드는 Handler 에서 상속되고, 출력이 없으므로, 명시적 flush() 호출이 필요할 수도 있습니다.

setStream(stream)

지정한 값이 현재 값과 다르면, 인스턴스의 스트림을 지정된 값으로 설정합니다. 새 스트림이 설정되기 전에 이전 스트림이 플러시 됩니다.

매개변수:

stream – 처리기가 사용할 스트림.

반환:

the old stream, if the stream was changed, or None if it wasn’t.

Added in version 3.7.

terminator

포맷된 레코드를 스트림에 쓸 때 종결자로 사용되는 문자열. 기본값은 '\n'입니다.

줄 바꿈 종료를 원하지 않으면, 처리기 인스턴스의 terminator 어트리뷰트를 빈 문자열로 설정할 수 있습니다.

이전 버전에서는, 종결자가 '\n'으로 하드 코딩되었습니다.

Added in version 3.2.

FileHandler

핵심 logging 패키지에 있는 FileHandler 클래스는 로깅 출력을 디스크 파일로 보냅니다. StreamHandler 에서 출력 기능을 상속받습니다.

class logging.FileHandler(filename, mode='a', encoding=None, delay=False, errors=None)

Returns a new instance of the FileHandler class. The specified file is opened and used as the stream for logging. If mode is not specified, 'a' is used. If encoding is not None, it is used to open the file with that encoding. If delay is true, then file opening is deferred until the first call to emit(). By default, the file grows indefinitely. If errors is specified, it’s used to determine how encoding errors are handled.

버전 3.6에서 변경: 문자열 값뿐만 아니라, Path 객체도 filename 인자로 허용됩니다.

버전 3.9에서 변경: errors 매개 변수가 추가되었습니다.

close()

파일을 닫습니다.

emit(record)

레코드를 파일에 출력합니다.

Note that if the file was closed due to logging shutdown at exit and the file mode is ‘w’, the record will not be emitted (see bpo-42378 [https://bugs.python.org/issue?@action=redirect&bpo=42378]).

NullHandler

Added in version 3.1.

핵심 logging 패키지에 있는 NullHandler 클래스는 포맷이나 출력을 일절 하지 않습니다. 기본적으로 라이브러리 개발자가 사용하는 ‘no-op’ 처리기입니다.

class logging.NullHandler

NullHandler 클래스의 새로운 인스턴스를 반환합니다.

emit(record)

이 메서드는 아무것도 하지 않습니다.

handle(record)

이 메서드는 아무것도 하지 않습니다.

createLock()

액세스를 직렬화해야 하는 하부 I/O가 없으므로, 이 메서드는 록으로 None 을 반환합니다.

NullHandler 사용법에 대한 더 많은 정보는 라이브러리 로깅 구성를 참조하세요.

WatchedFileHandler

logging.handlers 모듈에 있는 WatchedFileHandler 클래스는 로깅 중인 파일을 감시하는 FileHandler 입니다. 파일이 변경되면, 닫은 후에 같은 이름의 파일을 다시 엽니다.

로그 파일 회전을 수행하는 newsyslog 나 logrotate 와 같은 프로그램의 사용으로 인해 파일이 변경될 수 있습니다. 유닉스/리눅스에서 사용하기 위한 이 처리기는 마지막 출력 이후에 파일이 변경되었는지 감시합니다. (파일의 장치나 inode가 변경되면 파일이 변경된 것으로 간주합니다.) 파일이 변경되면, 이전 파일 스트림이 닫히고, 새 스트림을 얻기 위해 파일을 엽니다.

이 처리기는 윈도우에서 사용하기에 적합하지 않습니다. 윈도우에서는 열린 로그 파일을 이동하거나 이름을 변경할 수 없어서 - logging은 파일을 배타적 록으로 엽니다 - 이런 처리기가 필요하지 않기 때문입니다. 또한 ST_INO 는 윈도우에서 지원되지 않습니다; stat()는 항상 이 값에 대해 0을 반환합니다.

class logging.handlers.WatchedFileHandler(filename, mode='a', encoding=None, delay=False, errors=None)

Returns a new instance of the WatchedFileHandler class. The specified file is opened and used as the stream for logging. If mode is not specified, 'a' is used. If encoding is not None, it is used to open the file with that encoding. If delay is true, then file opening is deferred until the first call to emit(). By default, the file grows indefinitely. If errors is provided, it determines how encoding errors are handled.

버전 3.6에서 변경: 문자열 값뿐만 아니라, Path 객체도 filename 인자로 허용됩니다.

버전 3.9에서 변경: errors 매개 변수가 추가되었습니다.

reopenIfNeeded()

파일이 변경되었는지 확인합니다. 그렇다면, 기존 스트림을 플러시 한 후 닫고, 파일을 다시 엽니다. 일반적으로 레코드를 파일로 출력하기 전에 수행합니다.

Added in version 3.6.

emit(record)

레코드를 파일에 출력하지만, 파일이 변경되었을 때 다시 열기 위해 reopenIfNeeded()를 먼저 호출합니다.

BaseRotatingHandler

logging.handlers 모듈에 있는 BaseRotatingHandler 클래스는 회전하는 파일 처리기들(RotatingFileHandler와 TimedRotatingFileHandler)의 베이스 클래스입니다. 이 클래스의 인스턴스를 만들 필요는 없지만, 재정의가 필요할 수 있는 어트리뷰트와 메서드가 있습니다.

class logging.handlers.BaseRotatingHandler(filename, mode, encoding=None, delay=False, errors=None)

매개 변수는 FileHandler 와 같습니다. 어트리뷰트는 다음과 같습니다:

namer

이 어트리뷰트가 콜러블로 설정되면, rotation_filename() 메서드는 이 콜러블에 위임합니다. 콜러블로 전달되는 매개 변수는 rotation_filename()로 전달되는 것입니다.

참고

namer 함수는 롤오버 중에 꽤 자주 호출되므로, 가능한 한 간단하고 빨라야 합니다. 또한, 주어진 입력에 대해 매번 같은 출력을 반환해야 합니다, 그렇지 않으면 롤오버 동작이 예상대로 작동하지 않을 수 있습니다.

It’s also worth noting that care should be taken when using a namer to preserve certain attributes in the filename which are used during rotation. For example, RotatingFileHandler expects to have a set of log files whose names contain successive integers, so that rotation works as expected, and TimedRotatingFileHandler deletes old log files (based on the backupCount parameter passed to the handler’s initializer) by determining the oldest files to delete. For this to happen, the filenames should be sortable using the date/time portion of the filename, and a namer needs to respect this. (If a namer is wanted that doesn’t respect this scheme, it will need to be used in a subclass of TimedRotatingFileHandler which overrides the getFilesToDelete() method to fit in with the custom naming scheme.)

Added in version 3.3.

rotator

이 어트리뷰트가 콜러블로 설정되면, rotate() 메서드는 이 콜러블에 위임합니다. 콜러블로 전달되는 매개 변수는 rotate()로 전달되는 것입니다.

Added in version 3.3.

rotation_filename(default_name)

회전할 때 로그 파일의 파일명을 수정합니다.

사용자 정의 파일명을 제공할 수 있게 하려고 제공됩니다.

기본 구현은 처리기의 ‘namer’ 어트리뷰트를(콜러블이라면) 호출하는데, 기본 이름을 전달합니다. 어트리뷰트가 콜러블이 아니면 (기본값은 None 입니다), 이름은 변경되지 않고 반환됩니다.

매개변수:

default_name – 로그 파일의 기본 이름.

Added in version 3.3.

rotate(source, dest)

회전할 때, 현재 로그를 회전합니다.

기본 구현은 처리기의 ‘rotator’ 어트리뷰트를(콜러블이라면) 호출하는데, source와 dest 인자를 전달합니다. 어트리뷰트가 콜러블이 아니면 (기본값은 None 입니다), source를 dest 로 단순히 이름을 바꿉니다.

매개변수:

source – 소스 파일명. 이것은 일반적으로 기본 파일명입니다, 예를 들어 ‘test.log’.

dest – 대상 파일명. 이것은 일반적으로 소스가 회전되는 곳입니다, 예를 들어 ‘test.log.1’.

Added in version 3.3.

어트리뷰트가 존재하는 이유는 서브 클래싱해야 할 필요를 줄이는 것입니다 - RotatingFileHandler와 TimedRotatingFileHandler 의 인스턴스에 같은 콜러블을 사용할 수 있습니다. namer 나 rotator 콜러블이 예외를 발생시키면, emit() 동안 발생하는 다른 예외와 같은 방식으로 처리됩니다, 즉 처리기의 handleError() 메서드를 통해.

회전 처리를 더 크게 변경해야 하면, 메서드를 재정의할 수 있습니다.

예는 rotator와 namer를 사용해서 로그 회전 처리하기를 보십시오.

RotatingFileHandler

logging.handlers 모듈에 있는 RotatingFileHandler 클래스는 디스크 로그 파일 회전을 지원합니다.

class logging.handlers.RotatingFileHandler(filename, mode='a', maxBytes=0, backupCount=0, encoding=None, delay=False, errors=None)

RotatingFileHandler 클래스의 새로운 인스턴스를 반환합니다. 지정된 파일이 열리고 로깅을 위한 스트림으로 사용됩니다. mode 가 지정되지 않으면, 'a' 가 사용됩니다. encoding 이 None 이 아니면, encoding을 사용하여 파일을 엽니다. delay 가 참이면, 파일 열기는 emit()의 첫 번째 호출이 있을 때까지 연기됩니다. 기본적으로, 파일은 제한 없이 커집니다. errors가 제공되면, 인코딩 에러 처리 방법을 결정합니다.

미리 결정된 크기에서 파일을 롤오버 (rollover) 하기 위해 maxBytes 와 backupCount 값을 사용할 수 있습니다. 크기가 초과하려고 할 때, 파일이 닫히고 출력을 위해 새 파일이 조용히 열립니다. 롤오버는 현재 로그 파일이 거의 maxBytes 길이일 때마다 발생합니다; 그러나 maxBytes 나 backupCount 가 0이면 롤오버가 발생하지 않으므로, 일반적으로 backupCount 를 1 이상으로 설정하고, 0이 아닌 maxBytes를 사용하기를 원할 겁니다. backupCount 가 0이 아니면, 시스템은 파일명에 확장자 ‘.1’, ‘.2’ 등을 추가하여 지난 로그 파일을 저장합니다. 예를 들어, backupCount 가 5이고 기본 파일명이 app.log 면, app.log, app.log.1, app.log.2부터 app.log.5 까지의 파일을 얻게 됩니다. 기록되는 파일은 항상 app.log 입니다. 이 파일이 채워지면, 닫히고 app.log.1 로 이름이 변경됩니다, 그리고 파일 app.log.1, app.log.2 등이 존재하면, 이것들도 각기 app.log.2, app.log.3 등으로 이름이 변경됩니다.

버전 3.6에서 변경: 문자열 값뿐만 아니라, Path 객체도 filename 인자로 허용됩니다.

버전 3.9에서 변경: errors 매개 변수가 추가되었습니다.

doRollover()

위에서 설명한 대로 롤오버를 수행합니다.

emit(record)

앞에서 설명한 대로 롤오버를 처리하면서, 파일에 레코드를 출력합니다.

TimedRotatingFileHandler

logging.handlers 모듈에 있는 TimedRotatingFileHandler 클래스는 특정 시간 간격의 디스크 로그 파일 회전을 지원합니다.

class logging.handlers.TimedRotatingFileHandler(filename, when='h', interval=1, backupCount=0, encoding=None, delay=False, utc=False, atTime=None, errors=None)

TimedRotatingFileHandler 클래스의 새로운 인스턴스를 반환합니다. 지정된 파일이 열리고 로깅을 위한 스트림으로 사용됩니다. 회전 시 파일명 접미사도 설정합니다. when 과 interval 에 따라 회전이 일어납니다.

when 을 사용하여 interval 의 유형을 지정할 수 있습니다. 가능한 값의 목록은 아래와 같습니다. 대소 문자를 구분하지 않는다는 것에 유의하세요.

값

interval의 유형

atTime 이 사용되는지와 사용되는 방식

'S'

초

무시됩니다

'M'

분

무시됩니다

'H'

시간

무시됩니다

'D'

일

무시됩니다

'W0'-'W6'

요일 (0=월요일)

최초 롤오버 시간을 계산하는 데 사용됩니다

'midnight'

atTime 을 지정하지 않으면 자정에, 그렇지 않으면 atTime 에 롤오버 합니다

최초 롤오버 시간을 계산하는 데 사용됩니다

요일 기반 회전을 사용할 때, 월요일은 ‘W0’, 화요일은 ‘W1’, 등등 일요일은 ‘W6’까지 지정하십시오. 이 경우, interval 에 전달된 값은 사용되지 않습니다.

시스템은 파일명에 확장자를 추가하여 지난 로그 파일을 저장합니다. 확장자는 날짜와 시간 기반이며, 롤오버 간격에 따라 strftime 형식 %Y-%m-%d_%H-%M-%S 이나 그 앞부분을 사용합니다.

다음 롤오버 시간을 처음 계산할 때 (처리기가 만들어질 때), 기존 로그 파일의 마지막 수정 시간 또는 (없으면) 현재 시각이 다음 회전이 발생할 때를 계산하는 데 사용됩니다.

utc 인자가 참이면, UTC 시간이 사용됩니다; 그렇지 않으면 현지 시간이 사용됩니다.

backupCount 가 0이 아니면, 최대 backupCount 개의 파일이 보관되고, 롤오버가 발생할 때 더 많은 파일이 생성되면 가장 오래된 파일이 삭제됩니다. 삭제 논리는 interval을 사용하여 삭제할 파일을 결정하므로, interval을 변경하면 오래된 파일이 남아있을 수 있습니다.

delay 가 참이면, 파일 열기는 emit()에 대한 첫 번째 호출까지 지연됩니다.

atTime 이 None 이 아니면, 반드시 datetime.time 인스턴스여야 하는데, 롤오버가 “자정에” 또는 “특정 요일에” 발생하도록 설정된 경우에 롤오버가 발생하는 시간을 지정합니다. 이 경우, atTime 값은 최초 롤오버를 계산하는 데 사용되며, 이후 롤오버는 일반적인 간격 계산을 통해 계산됩니다.

errors가 지정되면, 인코딩 에러 처리 방법을 결정하는 데 사용됩니다.

참고

최초 롤오버 시간의 계산은 처리기가 초기화될 때 수행됩니다. 후속 롤오버 시간 계산은 롤오버가 발생하는 경우에만 수행되며, 롤오버는 출력을 내보낼 때만 발생합니다. 이것을 명심하지 않으면, 혼란이 생길 수 있습니다. 예를 들어, “매분” 간격을 설정하면, 이것이 항상 1분 간격의 (파일명을 갖는) 로그 파일들을 보게 된다는 것을 뜻하지는 않습니다; 응용 프로그램을 실행하는 동안, 로그 출력이 1분당 한 번보다 더 자주 발생하면, 1분 간격의 로그 파일을 볼 것으로 예상할 수 있습니다. 반면, (가령) 로깅 메시지가 5분마다 한 번만 출력되면, 출력이 없는 (따라서 롤오버가 없는) 분에 해당하는 파일 시간의 틈이 생깁니다.

버전 3.4에서 변경: atTime 매개 변수가 추가되었습니다.

버전 3.6에서 변경: 문자열 값뿐만 아니라, Path 객체도 filename 인자로 허용됩니다.

버전 3.9에서 변경: errors 매개 변수가 추가되었습니다.

doRollover()

위에서 설명한 대로 롤오버를 수행합니다.

emit(record)

위에서 설명한 대로 롤오버를 처리하면서, 파일에 레코드를 출력합니다.

getFilesToDelete()

Returns a list of filenames which should be deleted as part of rollover. These are the absolute paths of the oldest backup log files written by the handler.

SocketHandler

logging.handlers 모듈에 있는 SocketHandler 클래스는 로깅 출력을 네트워크 소켓에 보냅니다. 베이스 클래스는 TCP 소켓을 사용합니다.

class logging.handlers.SocketHandler(host, port)

host 와 port로 주어진 주소의 원격 기계와 통신하기 위한, SocketHandler 클래스의 새로운 인스턴스를 반환합니다.

버전 3.4에서 변경: port가 None으로 지정되면, host의 값을 사용하여 유닉스 도메인 소켓이 만들어집니다 - 그렇지 않으면 TCP 소켓이 만들어집니다.

close()

소켓을 닫습니다.

emit()

레코드의 어트리뷰트 딕셔너리를 피클하고 바이너리 형식으로 소켓에 씁니다. 소켓에 에러가 있으면 조용히 패킷을 버립니다. 이전에 연결이 끊어졌으면, 연결을 다시 맺습니다. 수신 단에서 레코드를 LogRecord로 역 피클 하려면, makeLogRecord() 함수를 사용하십시오.

handleError()

emit() 중에 발생한 에러를 처리합니다. 가장 큰 원인은 연결이 끊어지는 것입니다. 다음 이벤트에서 다시 시도할 수 있도록 소켓을 닫습니다.

makeSocket()

이것은 서브 클래스가 원하는 소켓의 정확한 유형을 정의 할 수 있게 하는 팩토리 메서드입니다. 기본 구현은 TCP 소켓(socket.SOCK_STREAM)을 만듭니다.

makePickle(record)

레코드의 어트리뷰트 딕셔너리를 바이너리 형식으로 피클하고 길이를 앞에 붙여서, 소켓을 통해 전송할 준비가 된 상태로 반환합니다. 이 연산의 세부 사항은 다음과 동등합니다:

data = pickle.dumps(record_attr_dict, 1)
datalen = struct.pack('>L', len(data))
return datalen + data

피클은 완전히 안전하지 않습니다. 보안이 염려되면, 이 메서드를 재정의하여 더욱 안전한 메커니즘을 구현할 수 있습니다. 예를 들어, HMAC를 사용하여 피클에 서명한 다음 수신 단에서 확인하거나, 수신 단에서 전역 객체의 역 피클링을 비활성화할 수 있습니다.

send(packet)

피클 된 바이트열 packet 을 소켓으로 보냅니다. 보내진 바이트열의 형식은 makePickle()의 설명서에 있습니다.

이 함수는 네트워크가 붐빌 때 발생할 수 있는 부분 전송을 허용합니다.

createSocket()

소켓을 만들려고 합니다; 실패 시, 지수 백 오프 알고리즘을 사용합니다. 최초 실패 시 처리기는 보내려는 메시지를 버립니다. 후속 메시지가 같은 인스턴스에 의해 처리될 때, 일정한 시간이 지날 때까지 연결을 시도하지 않습니다. 기본 파라미터를 쓸 때, 최초 지연은 1초이고, 지연 후에도 연결을 만들 수 없으면, 처리기가 최대 30초가 될 때까지 매번 지연 시간을 두 배로 늘립니다.

이 동작은 다음 처리기 어트리뷰트에 의해 제어됩니다:

retryStart (최초 지연, 기본값은 1.0 초).

retryFactor (배율, 기본값은 2.0).

retryMax (최대 지연, 기본값은 30.0 초).

이것은, 처리기가 사용된 후에 원격 수신기가 시작되면, 메시지가 손실될 수 있음을 뜻합니다 (처리기가 지연이 경과 할 때까지 연결을 시도하지조차 않고, 지연 기간에 메시지를 조용히 버리기 때문입니다).

DatagramHandler

logging.handlers 모듈에 있는 DatagramHandler 클래스는 UDP 소켓을 통해 로깅 메시지를 보낼 수 있도록 SocketHandler를 상속합니다.

class logging.handlers.DatagramHandler(host, port)

host 와 port로 주어진 주소의 원격 기계와 통신하기 위한, DatagramHandler 클래스의 새로운 인스턴스를 반환합니다.

참고

As UDP is not a streaming protocol, there is no persistent connection between an instance of this handler and host. For this reason, when using a network socket, a DNS lookup might have to be made each time an event is logged, which can introduce some latency into the system. If this affects you, you can do a lookup yourself and initialize this handler using the looked-up IP address rather than the hostname.

버전 3.4에서 변경: port가 None으로 지정되면, host의 값을 사용하여 유닉스 도메인 소켓이 만들어집니다 - 그렇지 않으면 UDP 소켓이 만들어집니다.

emit()

레코드의 어트리뷰트 딕셔너리를 피클하고 바이너리 형식으로 소켓에 씁니다. 소켓에 에러가 있으면 조용히 패킷을 버립니다. 수신 단에서 레코드를 LogRecord로 역 피클 하려면, makeLogRecord() 함수를 사용하십시오.

makeSocket()

UDP 소켓(socket.SOCK_DGRAM)을 만들기 위해 SocketHandler의 팩토리 메서드가 여기에서 재정의되었습니다.

send(s)

피클 된 바이트열을 소켓으로 보냅니다. 보낸 바이트열의 형식은 SocketHandler.makePickle() 설명서에 있습니다.

SysLogHandler

logging.handlers 모듈에 있는 SysLogHandler 클래스는 원격 또는 로컬 유닉스 syslog로 로깅 메시지를 보내는 것을 지원합니다.

class logging.handlers.SysLogHandler(address=('localhost', SYSLOG_UDP_PORT), facility=LOG_USER, socktype=socket.SOCK_DGRAM)

(host, port) 튜플 형태의 address로 주어진 주소의 원격 유닉스 기계와 통신하기 위한 SysLogHandler 클래스의 새 인스턴스를 돌려줍니다. address 를 지정하지 않으면 ('localhost', 514)가 사용됩니다. 주소는 소켓을 여는 데 사용됩니다. (host, port) 튜플을 제공하는 대신, 주소를 문자열로 제공할 수 있습니다, 예를 들어 ‘/dev/log’. 이 경우, 메시지를 syslog로 보내는데 유닉스 도메인 소켓이 사용됩니다. facility 가 지정되지 않으면, LOG_USER가 사용됩니다. 열리는 소켓의 유형은 socktype 인자에 따라 달라지며, 기본값은 socket.SOCK_DGRAM이고, 따라서 UDP 소켓이 열립니다. TCP 소켓을 열려면 (rsyslog와 같은 최신 syslog 데몬을 사용할 때), socket.SOCK_STREAM 값을 지정하십시오.

서버가 UDP 포트 514에서 수신을 기다리지 않으면, SysLogHandler가 작동하지 않는 것처럼 보일 수 있습니다. 이 경우, 도메인 소켓에 대해 사용해야 하는 주소를 확인하십시오 - 이는 시스템에 따라 다릅니다. 예를 들어 리눅스에서는 보통 ‘/dev/log’ 이지만 OS/X에서는 ‘/var/run/syslog’ 입니다. 플랫폼을 확인하고 적절한 주소를 사용해야 합니다 (응용 프로그램을 여러 플랫폼에서 실행해야 하는 경우 실행 시간에 검사를 수행해야 할 수도 있습니다). 윈도우에서는, UDP 옵션을 사용해야 합니다.

참고

On macOS 12.x (Monterey), Apple has changed the behaviour of their syslog daemon - it no longer listens on a domain socket. Therefore, you cannot expect SysLogHandler to work on this system.

See gh-91070 [https://github.com/python/cpython/issues/91070] for more information.

버전 3.2에서 변경: socktype 이 추가되었습니다.

close()

원격 호스트로의 소켓을 닫습니다.

createSocket()

Tries to create a socket and, if it’s not a datagram socket, connect it to the other end. This method is called during handler initialization, but it’s not regarded as an error if the other end isn’t listening at this point - the method will be called again when emitting an event, if there is no socket at that point.

Added in version 3.11.

emit(record)

레코드가 포맷된 다음, syslog 서버로 전송됩니다. 예외 정보가 있으면, 서버로 보내 지지 않습니다.

버전 3.2.1에서 변경: (bpo-12168 [https://bugs.python.org/issue?@action=redirect&bpo=12168]를 보세요.) 이전 버전에서, syslog 데몬으로 보낸 메시지는 NUL 바이트로 항상 종료되었는데, 이전 버전의 데몬에서 관련 사양(RFC 5424 [https://datatracker.ietf.org/doc/html/rfc5424.html])에 없는데도 불구하고 NUL 종료 메시지를 요구했기 때문입니다. 최신 버전의 데몬은 NUL 바이트를 기대하지는 않지만, 있는 경우 이를 제거하고, 더 최근의 (RFC 5424와 더 가깝게 일치하는) 데몬은 NUL 바이트를 메시지 일부로 전달합니다.

이러한 모든 다른 데몬 동작에 직면하여 syslog 메시지를 더욱 쉽게 처리할 수 있도록, NUL 바이트를 추가하는 작업은 클래스 수준 어트리뷰트 append_nul을 사용하여 구성할 수 있게 만들었습니다. 기본값은 True(기존 동작 유지)이지만, 특정 인스턴스가 NUL 종결자를 추가하지 않도록 SysLogHandler 인스턴스에서 False로 설정할 수 있습니다.

버전 3.3에서 변경: (bpo-12419 [https://bugs.python.org/issue?@action=redirect&bpo=12419]를 보세요.) 이전 버전에서는, 메시지 소스를 식별하는 “ident” 나 “tag” 접두사를 위한 기능이 없었습니다. 이제는 클래스 수준의 어트리뷰트를 사용하여 지정할 수 있습니다, ""을 기본값으로 사용하여 기존 동작을 유지하지만, SysLogHandler 인스턴스에서 재정의하여 해당 인스턴스가 처리하는 모든 메시지에 ident를 추가하도록 할 수 있습니다. 제공된 ident는 바이트열이 아닌 텍스트여야 하며 그대로 메시지 앞에 추가됩니다.

encodePriority(facility, priority)

시설(facility)과 우선순위를 정수로 인코딩합니다. 문자열이나 정수를 전달할 수 있습니다 - 문자열이 전달되면, 내부 매핑 딕셔너리를 사용하여 정수로 변환합니다.

LOG_ 기호 값은 SysLogHandler에 정의되고 sys/syslog.h 헤더 파일에 정의된 값을 그대로 옮깁니다.

우선순위

이름 (문자열)

기호 값

alert

LOG_ALERT

crit 또는 critical

LOG_CRIT

debug

LOG_DEBUG

emerg 또는 panic

LOG_EMERG

err 또는 error

LOG_ERR

info

LOG_INFO

notice

LOG_NOTICE

warn 또는 warning

LOG_WARNING

시설

이름 (문자열)

기호 값

auth

LOG_AUTH

authpriv

LOG_AUTHPRIV

cron

LOG_CRON

daemon

LOG_DAEMON

ftp

LOG_FTP

kern

LOG_KERN

lpr

LOG_LPR

mail

LOG_MAIL

news

LOG_NEWS

syslog

LOG_SYSLOG

user

LOG_USER

uucp

LOG_UUCP

local0

LOG_LOCAL0

local1

LOG_LOCAL1

local2

LOG_LOCAL2

local3

LOG_LOCAL3

local4

LOG_LOCAL4

local5

LOG_LOCAL5

local6

LOG_LOCAL6

local7

LOG_LOCAL7

mapPriority(levelname)

로깅 수준 이름을 syslog 우선순위 이름으로 매핑합니다. 사용자 정의 수준을 사용하거나 기본 알고리즘이 여러분의 요구에 적합하지 않으면, 이 값을 재정의해야 할 수 있습니다. 기본 알고리즘은 DEBUG, INFO, WARNING, ERROR 및 CRITICAL을 동등한 syslog 이름으로 매핑하고, 다른 모든 수준 이름은 ‘warning’으로 매핑합니다.

NTEventLogHandler

logging.handlers 모듈에 있는 NTEventLogHandler 클래스는 로깅 메시지를 로컬 윈도우 NT, 윈도우 2000 또는 윈도우 XP 이벤트 로그로 보내는 것을 지원합니다. 사용할 수 있으려면 먼저 Mark Hammond의 파이썬 용 Win32 확장이 설치되어 있어야 합니다.

class logging.handlers.NTEventLogHandler(appname, dllname=None, logtype='Application')

NTEventLogHandler 클래스의 새 인스턴스를 반환합니다. appname 은 이벤트 로그에 나타나는 응용 프로그램 이름을 정의하는 데 사용됩니다. 이 이름을 사용하여 적절한 레지스트리 항목이 만들어집니다. dllname 은 로그에 보관할 메시지 정의를 포함하는 .dll 또는 .exe의 완전히 정규화된 경로명을 제공해야 합니다 (지정되지 않으면, 'win32service.pyd'이 사용됩니다 - 이것은 Win32 확장과 함께 설치되며 몇 가지 기본 자리 표시자 메시지 정의를 포함합니다. 이 자리 표시자를 사용하면 전체 메시지 소스가 로그에 보관되므로 이벤트 로그가 커진다는 것에 유의하십시오. 간략한 로그를 원하면, 이벤트 로그에서 사용할 원하는 메시지 정의가 포함된 .dll 또는 .exe의 이름을 전달해야 합니다). logtype 은 'Application', 'System' 또는 'Security' 중 하나이며, 기본값은 'Application'입니다.

close()

이 시점에서, 이벤트 로그 항목의 소스로서의 응용 프로그램 이름을 레지스트리에서 제거할 수 있습니다. 그러나, 이렇게 하면, 이벤트 로그 뷰어에서 의도한 대로 이벤트를 볼 수 없게 됩니다 - 이벤트 로그 뷰어는 .dll 이름을 가져오기 위해 레지스트리에 액세스할 수 있어야 합니다. 현재 버전은 그렇게 하지 않습니다.

emit(record)

메시지 ID, 이벤트 범주 및 이벤트 유형을 결정한 다음, 메시지를 NT 이벤트 로그에 기록합니다.

getEventCategory(record)

레코드의 이벤트 범주를 반환합니다. 여러분 자신의 범주를 지정하려면, 이것을 재정의하십시오. 이 버전은 0을 반환합니다.

getEventType(record)

레코드의 이벤트 유형을 반환합니다. 여러분 자신의 유형을 지정하려면, 이것을 재정의하십시오. 이 버전은 처리기의 typemap 어트리뷰트를 사용하여 매핑하는데, __init__()에서 DEBUG, INFO, WARNING, ERROR 및 CRITICAL에 대한 매핑이 포함된 딕셔너리로 설정됩니다. 여러분 자신의 수준을 사용한다면, 이 메서드를 재정의하거나 처리기의 typemap 어트리뷰트에 적절한 딕셔너리를 배치해야 합니다.

getMessageID(record)

레코드의 메시지 ID를 반환합니다. 여러분 자신의 메시지를 사용한다면, 로거에 전달된 msg를 포맷 문자열이 아닌 ID로 사용할 수 있습니다. 그런 다음 여기에서 딕셔너리 조회를 사용하여 메시지 ID를 가져올 수 있습니다. 이 버전은 win32service.pyd의 기본 메시지 ID인 1을 반환합니다.

SMTPHandler

logging.handlers 모듈에 있는 SMTPHandler 클래스는 SMTP를 통해 전자 메일 주소로 로깅 메시지를 보내는 것을 지원합니다.

class logging.handlers.SMTPHandler(mailhost, fromaddr, toaddrs, subject, credentials=None, secure=None, timeout=1.0)

SMTPHandler 클래스의 새 인스턴스를 반환합니다. 인스턴스는 전자 메일의 보내는 주소, 받는 주소와 제목 줄을 사용하여 초기화됩니다. toaddrs 는 문자열 리스트여야 합니다. 비표준 SMTP 포트를 지정하려면, mailhost 인자에 (host, port) 튜플 형식을 사용하십시오. 문자열을 사용하면 표준 SMTP 포트가 사용됩니다. SMTP 서버가 인증을 요구하면, credentials 인자에 (username, password) 튜플을 지정할 수 있습니다.

보안 프로토콜(TLS)의 사용을 지정하려면, secure 인자에 튜플을 전달하십시오. 이것은 인증 자격 증명(credentials)이 제공될 때만 사용됩니다. 튜플은 빈 튜플이거나, 키 파일 이름을 가진 단일 값 튜플이거나, 키 파일과 인증서 파일의 이름을 가진 2-튜플이어야 합니다. (이 튜플은 smtplib.SMTP.starttls() 메서드에 전달됩니다.)

timeout 인자를 사용하여 SMTP 서버와의 통신에 시간제한을 지정할 수 있습니다.

버전 3.3에서 변경: Added the timeout parameter.

emit(record)

레코드를 포맷하고 지정된 주소로 보냅니다.

getSubject(record)

레코드에 종속적인 제목 줄을 지정하려면, 이 메서드를 재정의하십시오.

MemoryHandler

logging.handlers 모듈에 있는 MemoryHandler 클래스는 메모리에 로깅 레코드를 버퍼링하고, 주기적으로 대상 (target) 처리기로 플러시 하는 것을 지원합니다. 플러시는 버퍼가 꽉 찼거나 특정 심각도 이상의 이벤트가 발생할 때마다 발생합니다.

MemoryHandler는 추상 클래스이면서, 더 일반적인 BufferingHandler의 서브 클래스입니다. 이것은 레코드 로깅을 메모리에 버퍼링합니다. 각 레코드가 버퍼에 추가될 때마다, shouldFlush()를 호출하여 버퍼를 플러시 할지 확인합니다. 필요하면, flush()가 플러시를 수행할 것으로 기대합니다.

class logging.handlers.BufferingHandler(capacity)

지정된 용량(capacity)의 버퍼로 처리기를 초기화합니다. 여기서 capacity는 버퍼링 된 로깅 레코드 수를 의미합니다.

emit(record)

레코드를 버퍼에 추가합니다. shouldFlush()가 참을 반환하면 flush()를 호출하여 버퍼를 처리합니다.

flush()

For a BufferingHandler instance, flushing means that it sets the buffer to an empty list. This method can be overwritten to implement more useful flushing behavior.

shouldFlush(record)

버퍼의 용량이 찼으면 True를 반환합니다. 이 메서드는 사용자 정의 플러시 전략을 구현하기 위해 재정의될 수 있습니다.

class logging.handlers.MemoryHandler(capacity, flushLevel=ERROR, target=None, flushOnClose=True)

MemoryHandler 클래스의 새 인스턴스를 반환합니다. 인스턴스는 capacity(버퍼 된 레코드 수)의 버퍼 크기로 초기화됩니다. flushLevel을 지정하지 않으면, ERROR가 사용됩니다. target 이 지정되지 않으면, 이 처리기가 유용한 것을 하기 전에, setTarget()를 사용해 대상을 설정할 필요가 있습니다. flushOnClose 가 False로 지정되면, 처리기가 닫힐 때 버퍼가 플러시 되지 않습니다. 지정되지 않거나 True로 지정되면, 처리기가 닫힐 때 버퍼를 플러시 하는 이전 동작이 발생합니다.

버전 3.6에서 변경: flushOnClose 매개 변수가 추가되었습니다.

close()

flush()를 호출하고, 대상(target)을 None으로 설정하고, 버퍼를 비웁니다.

flush()

For a MemoryHandler instance, flushing means just sending the buffered records to the target, if there is one. The buffer is also cleared when buffered records are sent to the target. Override if you want different behavior.

setTarget(target)

이 처리기의 대상 처리기를 설정합니다.

shouldFlush(record)

버퍼 가득 참이나 레코드가 flushLevel 이상을 만드는지 확인합니다.

HTTPHandler

The HTTPHandler class, located in the logging.handlers module, supports sending logging messages to a web server, using either GET or POST semantics.

class logging.handlers.HTTPHandler(host, url, method='GET', secure=False, credentials=None, context=None)

HTTPHandler 클래스의 새 인스턴스를 반환합니다. host 는 특정 포트 번호를 사용해야 하면 host:port 형식일 수 있습니다. method 를 지정하지 않으면 GET이 사용됩니다. secure 가 참이면, HTTPS 연결이 사용됩니다. context 매개 변수는 ssl.SSLContext 인스턴스로 설정되어, HTTPS 연결에 사용되는 SSL 설정을 구성할 수 있습니다. credentials 가 지정되면, 기본 인증을 사용하여 HTTP ‘Authorization’ 헤더에 배치되는 사용자 ID와 암호로 구성된 2-튜플이어야 합니다. credentials를 지정하면, 사용자 ID와 암호가 단순 텍스트로 전달되지 않도록 secure=True를 지정해야 합니다.

버전 3.5에서 변경: context 매개 변수가 추가되었습니다.

mapLogRecord(record)

URL 인코딩되어 웹 서버로 전송되는, record에 기반한 딕셔너리를 제공합니다. 기본 구현은 record.__dict__를 반환합니다. 이 메서드는 재정의할 수 있는데, 예를 들어 LogRecord의 일부만 웹 서버로 보내지거나, 서버로 보내는 내용에 대한 보다 구체적인 사용자 정의가 필요한 경우입니다.

emit(record)

Sends the record to the web server as a URL-encoded dictionary. The mapLogRecord() method is used to convert the record to the dictionary to be sent.

참고

Since preparing a record for sending it to a web server is not the same as a generic formatting operation, using setFormatter() to specify a Formatter for a HTTPHandler has no effect. Instead of calling format(), this handler calls mapLogRecord() and then urllib.parse.urlencode() to encode the dictionary in a form suitable for sending to a web server.

QueueHandler

Added in version 3.2.

logging.handlers 모듈에 있는 QueueHandler 클래스는, queue 나 multiprocessing 모듈에 구현된 것과 같은 큐에 로깅 메시지를 보내는 것을 지원합니다.

Along with the QueueListener class, QueueHandler can be used to let handlers do their work on a separate thread from the one which does the logging. This is important in web applications and also other service applications where threads servicing clients need to respond as quickly as possible, while any potentially slow operations (such as sending an email via SMTPHandler) are done on a separate thread.

class logging.handlers.QueueHandler(queue)

QueueHandler 클래스의 새 인스턴스를 반환합니다. 인스턴스는 메시지를 보낼 큐로 초기화됩니다. queue는 임의의 큐류(queue-like) 객체일 수 있습니다; 메시지를 보내는 방법을 알아야 하는 enqueue() 메서드가 있는 그대로 사용합니다. 큐는 작업 추적 API를 갖도록 요구되지 않아서, queue에 SimpleQueue 인스턴스를 사용할 수 있습니다.

참고

If you are using multiprocessing, you should avoid using SimpleQueue and instead use multiprocessing.Queue.

emit(record)

Enqueues the result of preparing the LogRecord. Should an exception occur (e.g. because a bounded queue has filled up), the handleError() method is called to handle the error. This can result in the record silently being dropped (if logging.raiseExceptions is False) or a message printed to sys.stderr (if logging.raiseExceptions is True).

prepare(record)

큐에 넣기 위해 레코드를 준비합니다. 이 메서드에 의해 반환된 객체는 큐에 들어갑니다.

The base implementation formats the record to merge the message, arguments, exception and stack information, if present. It also removes unpickleable items from the record in-place. Specifically, it overwrites the record’s msg and message attributes with the merged message (obtained by calling the handler’s format() method), and sets the args, exc_info and exc_text attributes to None.

레코드를 dict 나 JSON 문자열로 변환하거나, 원본을 그대로 두고 레코드의 수정 된 복사본을 보내길 원한다면 이 메서드를 재정의할 수 있습니다.

참고

The base implementation formats the message with arguments, sets the message and msg attributes to the formatted message and sets the args and exc_text attributes to None to allow pickling and to prevent further attempts at formatting. This means that a handler on the QueueListener side won’t have the information to do custom formatting, e.g. of exceptions. You may wish to subclass QueueHandler and override this method to e.g. avoid setting exc_text to None. Note that the message / msg / args changes are related to ensuring the record is pickleable, and you might or might not be able to avoid doing that depending on whether your args are pickleable. (Note that you may have to consider not only your own code but also code in any libraries that you use.)

enqueue(record)

put_nowait()를 사용하여 큐에 레코드를 넣습니다; 블로킹 동작이나 시간제한이나, 사용자 정의 큐 구현을 사용하려면 이 메서드를 재정의할 수 있습니다.

listener

When created via configuration using dictConfig(), this attribute will contain a QueueListener instance for use with this handler. Otherwise, it will be None.

Added in version 3.12.

QueueListener

Added in version 3.2.

logging.handlers 모듈에 있는 QueueListener 클래스는 queue 나 multiprocessing 모듈에 구현된 것과 같은 큐에서 로깅 메시지를 수신하는 것을 지원합니다. 메시지는 내부 스레드의 큐에서 수신되고 처리를 위해 같은 스레드에서 하나 이상의 처리기로 전달됩니다. QueueListener 자체는 처리기가 아니지만, QueueHandler 와 함께 사용되기 때문에 여기에 설명되어 있습니다.

Along with the QueueHandler class, QueueListener can be used to let handlers do their work on a separate thread from the one which does the logging. This is important in web applications and also other service applications where threads servicing clients need to respond as quickly as possible, while any potentially slow operations (such as sending an email via SMTPHandler) are done on a separate thread.

class logging.handlers.QueueListener(queue, *handlers, respect_handler_level=False)

QueueListener 클래스의 새 인스턴스를 반환합니다. 인스턴스는 메시지를 보내는 큐와 큐에 있는 항목을 처리할 처리기의 리스트로 초기화됩니다. 큐는 임의의 큐류(queue-like) 객체일 수 있습니다; 메시지를 꺼내는 방법을 알아야 하는 dequeue() 메서드가 있는 그대로 사용합니다. 큐는 작업 추적 API를 갖도록 요구되지 않아서 (가능하면 사용됩니다), queue에 SimpleQueue 인스턴스를 사용할 수 있습니다.

참고

If you are using multiprocessing, you should avoid using SimpleQueue and instead use multiprocessing.Queue.

respect_handler_level이 True 면, 처리기에 메시지를 전달할지를 결정할 때, 처리기의 수준이 존중됩니다 (메시지의 수준과 비교); 그렇지 않으면, 이전 파이썬 버전과 같게 동작합니다 - 항상 각 메시지를 모든 처리기에 전달합니다.

버전 3.5에서 변경: respect_handler_level 인자가 추가되었습니다.

dequeue(block)

레코드를 큐에서 꺼내 반환합니다. 선택적으로 블록 됩니다.

기본 구현은 get()을 사용합니다. 시간제한을 사용하거나 사용자 정의 큐 구현을 사용하려면 이 메서드를 재정의할 수 있습니다.

prepare(record)

처리를 위해 레코드를 준비합니다.

이 구현은 단지 전달된 레코드를 반환합니다. 사용자 정의 직렬화를 수행하거나 처리기에 전달하기 전에 레코드를 조작해야 하면, 이 메서드를 재정의할 수 있습니다.

handle(record)

레코드를 처리합니다.

이것은 단지 모든 처리기로 레코드를 제공합니다. 처리기에 전달되는 실제 객체는 prepare()에서 반환된 객체입니다.

start()

수신기를 시작합니다.

이것은 처리하기 위해 큐에서 LogRecord를 관찰하는 배경 스레드를 시작합니다.

stop()

수신기를 정지합니다.

스레드가 종료하도록 요청한 다음, 스레드가 종료할 때까지 대기합니다. 응용 프로그램이 종료되기 전에 이 함수를 호출하지 않으면, 레코드가 큐에 남아있을 수 있고, 이것들은 처리되지 않습니다.

enqueue_sentinel()

수신자에게 종료하도록 알리기 위해 큐에 종료 신호(sentinel)를 씁니다. 이 구현은 put_nowait()를 사용합니다. 시간제한을 사용하거나 사용자 정의 큐 구현을 사용하려면 이 메서드를 재정의할 수 있습니다.

Added in version 3.3.

더 보기

모듈 logging

logging 모듈에 관한 API 레퍼런스.

모듈 logging.config

logging 모듈용 구성 API.

getpass — Portable password input

소스 코드: Lib/getpass.py [https://github.com/python/cpython/tree/main/Lib/getpass.py]

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

getpass 모듈은 두 함수를 제공합니다:

getpass.getpass(prompt='Password: ', stream=None)

에코 없이 사용자에게 암호를 묻습니다. 사용자는 prompt 문자열을 사용하여 프롬프트 됩니다. 기본값은 'Password: '입니다. 유닉스에서 프롬프트는 필요하다면 replace 에러 처리기를 사용하여 파일류 객체 stream에 기록됩니다. stream는 제어 터미널(/dev/tty)이나 사용할 수 없으면 sys.stderr를 기본값으로 사용합니다 (이 인자는 윈도우에서 무시됩니다).

에코가 없는 입력을 사용할 수 없으면, getpass()는 stream에 경고 메시지를 인쇄하고, sys.stdin에서 읽고, GetPassWarning을 방출하는 것으로 돌아갑니다.

참고

IDLE 내에서 getpass를 호출하면, 대기 중인 창 자체가 아닌 IDLE을 시작한 터미널에서 입력이 수행될 수 있습니다.

exception getpass.GetPassWarning

패스워드 입력이 에코 될 때 방출되는 UserWarning 서브 클래스.

getpass.getuser()

사용자의 “로그인 이름”을 반환합니다.

This function checks the environment variables LOGNAME, USER, LNAME and USERNAME, in order, and returns the value of the first one which is set to a non-empty string. If none are set, the login name from the password database is returned on systems which support the pwd module, otherwise, an OSError is raised.

In general, this function should be preferred over os.getlogin().

버전 3.13에서 변경: Previously, various exceptions beyond just OSError were raised.

curses — Terminal handling for character-cell displays

Source code: Lib/curses [https://github.com/python/cpython/tree/main/Lib/curses]

curses 모듈은 이식성 있는 고급 터미널 처리를 위한 사실상의 표준인 curses 라이브러리에 대한 인터페이스를 제공합니다.

curses는 유닉스 환경에서 가장 널리 사용되지만, 윈도우, DOS 및 기타 시스템에서도 사용할 수 있는 버전이 있습니다. 이 확장 모듈은 리눅스와 유닉스의 BSD 변형에서 동작하는 오픈 소스 curses 라이브러리인 ncurses의 API와 일치하도록 설계되었습니다.

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

참고

설명서에 문자(character)가 언급될 때마다 정수, 한 문자 유니코드 문자열 또는 한 바이트 바이트열로 지정할 수 있습니다.

설명서에 문자 문자열(character string)이 언급될 때마다 유니코드 문자열이나 바이트열로 지정할 수 있습니다.

더 보기

모듈 curses.ascii

로케일 설정과 관계없이, ASCII 문자로 작업하기 위한 유틸리티.

모듈 curses.panel

curses 창에 깊이를 추가하는 패널 스택 확장.

모듈 curses.textpad

Emacs와 유사한 바인딩을 지원하는 curses를 위한 편집 가능한 텍스트 위젯.

파이썬 curses 프로그래밍

Andrew Kuchling과 Eric Raymond가 작성한, curses를 파이썬에서 사용하는 것에 대한 자습서 자료.

함수

curses 모듈은 다음 예외를 정의합니다:

exception curses.error

curses 라이브러리 함수가 에러를 반환할 때 발생하는 예외.

참고

함수나 메서드에 대한 x나 y 인자가 선택 사항일 때마다, 기본값은 현재 커서 위치입니다. attr이 선택적일 때마다 기본값은 A_NORMAL입니다.

curses 모듈은 다음 함수를 정의합니다:

curses.baudrate()

터미널의 출력 속도를 초당 비트 수로 반환합니다. 소프트웨어 터미널 에뮬레이터에서는 고정된 큰 값을 갖습니다. 역사적인 이유로 포함되었습니다; 이전에는, 시간 지연에 대한 출력 루프를 작성하는데, 때로는 회선 속도에 따라 인터페이스를 변경하는 데 사용되었습니다.

curses.beep()

짧은 주의 음을 냅니다.

curses.can_change_color()

프로그래머가 터미널에 표시되는 색상을 변경할 수 있는지에 따라 True나 False를 반환합니다.

curses.cbreak()

cbreak 모드로 들어갑니다. cbreak 모드(“드문(rare)” 모드라고도 합니다)에서는 일반 tty 줄 버퍼링이 꺼지고 문자를 하나씩 읽을 수 있습니다. 그러나, 원시(raw) 모드와 달리, 특수 문자(인터럽트(interrupt), 종료(quit), 일시 중단(suspend) 및 흐름 제어(flow control))는 tty 드라이버와 호출하는 프로그램에 영향을 미칩니다. raw()를 먼저 호출한 다음 cbreak()를 호출하면 터미널이 cbreak 모드로 유지됩니다.

curses.color_content(color_number)

0과 COLORS - 1 사이의 색상 color_number에서 빨강, 녹색 및 파랑 (RGB) 구성 요소의 강도(intensity)를 반환합니다. 주어진 색상에 대한 R,G,B 값이 포함된 3-튜플을 반환합니다. 이 값은 0(구성 요소 없음)과 1000(구성 요소의 최대량) 사이입니다.

curses.color_pair(pair_number)

Return the attribute value for displaying text in the specified color pair. Only the first 256 color pairs are supported. This attribute value can be combined with A_STANDOUT, A_REVERSE, and the other A_* attributes. pair_number() is the counterpart to this function.

curses.curs_set(visibility)

커서 상태를 설정합니다. visibility는 0, 1 또는 2로 설정될 수 있는데, 각각 보이지 않음(invisible), 보통, 매우 잘 보임(very visible)입니다. 터미널이 요청된 visibility를 지원하면, 이전 커서 상태를 반환합니다; 그렇지 않으면 예외가 발생합니다. 많은 터미널에서, “보이는(visible)” 모드는 밑줄 커서이고 “매우 잘 보이는(very visible)” 모드는 블록 커서입니다.

curses.def_prog_mode()

현재 터미널 모드를 “프로그램(program)” 모드로 저장합니다. 프로그램 모드는 실행 중인 프로그램이 curses를 사용 중인 모드입니다. (반대는 “셸(shell)” 모드이며, 프로그램이 curses를 사용하지 않을 때입니다.) 이후에 reset_prog_mode()를 호출하면 이 모드가 복원됩니다.

curses.def_shell_mode()

현재 터미널 모드를 “셸(shell)” 모드로 저장합니다. 셸 모드는 실행 중인 프로그램이 curses를 사용하지 않는 모드입니다. (반대는 “프로그램(program)” 모드이며, 프로그램이 curses 기능을 사용 중일 때입니다.) 이후에 reset_shell_mode()를 호출하면 이 모드가 복원됩니다.

curses.delay_output(ms)

출력에 ms 밀리초 일시 중지를 삽입합니다.

curses.doupdate()

물리적 화면을 갱신합니다. curses 라이브러리는 두 개의 데이터 구조를 유지합니다. 하나는 현재 물리적 화면 내용을 표현하고 다른 하나는 원하는 다음 상태를 나타내는 가상 화면을 표현합니다. doupdate()는 물리적 화면을 가상 화면과 일치하도록 갱신합니다.

가상 화면은 창에 addstr()과 같은 쓰기 연산이 수행된 후 noutrefresh() 호출로 갱신될 수 있습니다. 일반적인 refresh() 호출은 단순히 noutrefresh() 후에 doupdate() 하는 것입니다; 여러 개의 창을 갱신해야 하면, 모든 창에서 noutrefresh() 호출을 실행한 다음 단일 doupdate()를 실행하여 속도 성능을 높이고 아마도 화면 깜박임을 줄일 수 있습니다.

curses.echo()

반향(echo) 모드로 들어갑니다. 반향 모드에서는, 각 문자 입력이 입력되는 대로 화면에 반향을 일으킵니다.

curses.endwin()

라이브러리를 초기화 해제하고, 터미널을 정상 상태로 되돌립니다.

curses.erasechar()

사용자의 현재 지우기 문자(erase character)를 1바이트 바이트열 객체로 반환합니다. 유닉스 운영 체제에서 이는 curses 프로그램의 제어 tty의 특성이며, curses 라이브러리 자체에 의해 설정되지 않습니다.

curses.filter()

filter() 루틴을 사용하는 경우 initscr()을 호출하기 전에 호출해야 합니다. 이러한 호출 중에, 효과는 LINES가 1로 설정되고; clear, cup, cud, cud1, cuu1, cuu, vpa 기능이 비활성화되고; home 문자열이 cr 값으로 설정됩니다. 결과적으로 커서가 현재 줄에 갇혀서 화면이 갱신됩니다. 화면의 나머지 부분을 건드리지 않고 한 번에 한 글자(character-at-a-time) 줄 편집을 활성화하는데 사용될 수 있습니다.

curses.flash()

화면을 깜박입니다. 즉, 반전 비디오로 변경한 다음 짧은 간격으로 되돌립니다. 어떤 사람들은 beep()이 만드는 가청 주의 신호보다 이런 ‘시각적 벨’을 선호합니다.

curses.flushinp()

모든 입력 버퍼를 플러시 합니다. 이렇게 하면 사용자가 입력했지만, 아직 프로그램에서 처리하지 않은 모든 선행 입력(typeahead)을 모두 버립니다.

curses.getmouse()

After getch() returns KEY_MOUSE to signal a mouse event, this method should be called to retrieve the queued mouse event, represented as a 5-tuple (id, x, y, z, bstate). id is an ID value used to distinguish multiple devices, and x, y, z are the event’s coordinates. (z is currently unused.) bstate is an integer value whose bits will be set to indicate the type of event, and will be the bitwise OR of one or more of the following constants, where n is the button number from 1 to 5: BUTTONn_PRESSED, BUTTONn_RELEASED, BUTTONn_CLICKED, BUTTONn_DOUBLE_CLICKED, BUTTONn_TRIPLE_CLICKED, BUTTON_SHIFT, BUTTON_CTRL, BUTTON_ALT.

버전 3.10에서 변경: The BUTTON5_* constants are now exposed if they are provided by the underlying curses library.

curses.getsyx()

가상 화면 커서의 현재 좌표를 튜플 (y, x)로 반환합니다. leaveok가 현재 True이면, (-1, -1)을 반환합니다.

curses.getwin(file)

Read window related data stored in the file by an earlier window.putwin() call. The routine then creates and initializes a new window using that data, returning the new window object.

curses.has_colors()

터미널이 색상을 표시할 수 있으면 True를 반환합니다. 그렇지 않으면 False를 반환합니다.

curses.has_extended_color_support()

Return True if the module supports extended colors; otherwise, return False. Extended color support allows more than 256 color pairs for terminals that support more than 16 colors (e.g. xterm-256color).

Extended color support requires ncurses version 6.1 or later.

Added in version 3.10.

curses.has_ic()

터미널에 문자 삽입과 삭제 기능이 있으면 True를 반환합니다. 이 함수는 역사적인 이유로만 포함되는데, 모든 최신 소프트웨어 터미널 에뮬레이터에 이러한 기능이 있기 때문입니다.

curses.has_il()

터미널에 줄 삽입과 삭제 기능이 있거나, 영역 스크롤을 사용하여 시뮬레이션 할 수 있으면 True를 반환합니다. 이 함수는 역사적인 이유로만 포함되는데, 모든 최신 소프트웨어 터미널 에뮬레이터에 이러한 기능이 있기 때문입니다.

curses.has_key(ch)

키값 ch를 취하고, 현재 터미널 유형이 해당 값을 가진 키를 인식하면 True를 반환합니다.

curses.halfdelay(tenths)

사용자가 입력 한 문자를 프로그램에서 즉시 사용할 수 있다는 점에서 cbreak 모드와 유사한, 반 지연(half-delay) 모드에 사용됩니다. 그러나 tenths 10분의 1초 동안 블록한 후 아무것도 입력하지 않으면 예외가 발생합니다. tenths의 값은 1과 255 사이의 숫자여야 합니다. 반 지연 모드를 종료하려면 nocbreak()를 사용하십시오.

curses.init_color(color_number, r, g, b)

Change the definition of a color, taking the number of the color to be changed followed by three RGB values (for the amounts of red, green, and blue components). The value of color_number must be between 0 and COLORS - 1. Each of r, g, b, must be a value between 0 and 1000. When init_color() is used, all occurrences of that color on the screen immediately change to the new definition. This function is a no-op on most terminals; it is active only if can_change_color() returns True.

curses.init_pair(pair_number, fg, bg)

색상 쌍의 정의를 변경합니다. 세 가지 인자를 취합니다: 변경할 색상 쌍 번호, 전경색 번호 및 배경색 번호. pair_number의 값은 1과 COLOR_PAIRS - 1 사이여야 합니다 (0 색상 쌍은 검은 배경색에 흰 전경색으로 연결되어 있으며 변경할 수 없습니다). fg와 bg 인자의 값은 0과 COLORS - 1 사이, 또는, use_default_colors() 후에, -1이어야 합니다. 색상 쌍이 이전에 초기화되었으면, 화면이 새로 고쳐지고 해당 색상 쌍의 모든 항목이 새 정의로 변경됩니다.

curses.initscr()

라이브러리를 초기화합니다. 전체 화면을 나타내는 창 객체를 반환합니다.

참고

터미널을 여는 중 에러가 발생하면, 하부 curses 라이브러리가 인터프리터를 종료시킬 수 있습니다.

curses.is_term_resized(nlines, ncols)

resize_term()이 창 구조를 수정한다면 True를, 그렇지 않으면 False를 반환합니다.

curses.isendwin()

endwin()이 호출되었으면 (즉, curses 라이브러리가 초기화 해제되었다면) True를 반환합니다.

curses.keyname(k)

키 번호 k의 이름을 바이트열 객체로 반환합니다. 인쇄 가능한 ASCII 문자를 생성하는 키의 이름은 키의 문자입니다. 제어 키(control-key) 조합의 이름은 캐럿(b'^')과 그 뒤에오는 해당 인쇄 가능한 ASCII 문자로 구성된 2바이트 바이트열 객체입니다. 대체 키(alt-key) 조합(128–255)의 이름은 접두사 b'M-'와 그 뒤에 오는 해당 ASCII 문자의 이름으로 구성되는 바이트열 객체입니다.

curses.killchar()

사용자의 현재 줄 삭제 문자(line kill character)를 1바이트 바이트열 객체로 반환합니다. 유닉스 운영 체제에서 이는 curses 프로그램의 제어 tty의 특성이며, curses 라이브러리 자체에 의해 설정되지 않습니다.

curses.longname()

현재 터미널을 설명하는 terminfo 긴 이름 필드를 포함하는 바이트열 객체를 반환합니다. 자세한 설명의 최대 길이는 128자입니다. initscr()을 호출한 후에만 정의됩니다.

curses.meta(flag)

flag가 True이면, 8비트 문자 입력을 허용합니다. flag가 False이면 7비트 문자만 허용합니다.

curses.mouseinterval(interval)

Set the maximum time in milliseconds that can elapse between press and release events in order for them to be recognized as a click, and return the previous interval value. The default value is 200 milliseconds, or one fifth of a second.

curses.mousemask(mousemask)

마우스 이벤트가 보고되도록 설정하고, 튜플 (availmask, oldmask)를 반환합니다. availmask는 지정된 마우스 이벤트 중 보고 할 수 있는 것을 나타냅니다; 완전히 실패하면 0을 반환합니다. oldmask는 주어진 창의 마우스 이벤트 마스크의 이전 값입니다. 이 함수를 한 번도 호출하지 않으면, 마우스 이벤트가 보고되지 않습니다.

curses.napms(ms)

ms 밀리초 동안 휴면합니다.

curses.newpad(nlines, ncols)

주어진 수의 행과 열로 새로운 패드 데이터 구조에 대한 포인터를 만들고 반환합니다. 패드를 창 객체로 반환합니다.

패드는 화면 크기에 의해 제한되지 않으며, 화면의 특정 부분과 반드시 관련될 필요는 없다는 점을 제외하면 창과 같습니다. 큰 창이 필요할 때 패드를 사용할 수 있으며, 한 번에 창의 일부만 화면에 표시됩니다. 패드의 자동 새로 고침(가령 스크롤이나 입력 반향)은 일어나지 않습니다. 패드의 refresh()와 noutrefresh() 메서드는 표시할 패드의 부분과 표시할 화면의 위치를 지정하기 위해 6개의 인자가 필요합니다. 인자는 pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol입니다; p 인자는 표시할 패드 영역의 왼쪽 위 모서리를 가리키고, s 인자는 패드 영역이 표시될 화면 위의 클리핑 상자를 정의합니다.

curses.newwin(nlines, ncols)

curses.newwin(nlines, ncols, begin_y, begin_x)

왼쪽 위 모서리가 (begin_y, begin_x)이고, 높이/너비가 nlines/ncols 인 새 창을 반환합니다.

기본적으로, 창은 지정된 위치에서 화면 오른쪽 하단으로 확장됩니다.

curses.nl()

줄 바꿈(newline) 모드로 들어갑니다. 이 모드는 입력에서 리턴 키를 줄 바꿈으로 변환하고, 출력에서 줄 바꿈을 리턴(return)과 줄 넘김(line-feed)으로 변환합니다. 줄 바꿈 모드는 처음에 켜져 있습니다.

curses.nocbreak()

cbreak 모드를 종료합니다. 줄 버퍼링을 사용하는 일반 “요리된(cooked)” 모드로 돌아갑니다.

curses.noecho()

반향 모드를 종료합니다. 입력 문자 반향이 꺼집니다.

curses.nonl()

줄 바꿈 모드를 종료합니다. 입력에서 리턴을 줄 바꿈으로 변환하는 것을 비활성화하고, 출력에서 줄 바꿈을 줄 바꿈/리턴으로 저수준 변환하는 것을 비활성화합니다 (그러나 이것은 addch('\n')의 동작을 변경하지는 않는데, 항상 가상 화면에서 리턴(return)과 줄 넘김(line feed)에 동등한 역할을 합니다). 변환이 꺼져 있으면, curses가 때로 수직 동작 속도를 약간 올릴 수 있습니다; 또한, 입력에서 리턴 키를 감지할 수 있습니다.

curses.noqiflush()

noqiflush() 루틴이 사용되면, INTR, QUIT 및 SUSP 문자와 연관된 입력과 출력 큐의 일반 플러시가 수행되지 않습니다. 처리기가 종료한 후, 인터럽트가 발생하지 않은 것처럼 출력을 계속하려면 시그널 처리기에서 noqiflush()를 호출할 수 있습니다.

curses.noraw()

원시(raw) 모드를 종료합니다. 줄 버퍼링을 사용하는 일반 “요리된(cooked)” 모드로 돌아갑니다.

curses.pair_content(pair_number)

요청된 색상 쌍의 색상이 포함된 튜플 (fg, bg)를 반환합니다. pair_number의 값은 0과 COLOR_PAIRS - 1 사이여야 합니다.

curses.pair_number(attr)

속성값 attr로 설정된 색상 쌍의 번호를 반환합니다. color_pair()는 이 함수의 역입니다.

curses.putp(str)

tputs(str, 1, putchar)와 동등합니다; 현재 터미널에 대해 지정된 terminfo 기능의 값을 내보냅니다. putp()의 출력은 항상 표준 출력을 향함에 유의하십시오.

curses.qiflush([flag])

flag가 False이면, 효과는 noqiflush()를 호출하는 것과 같습니다. flag가 True이거나, 인자가 제공되지 않으면, 이러한 제어 문자를 읽을 때 큐가 플러시 됩니다.

curses.raw()

원시(raw) 모드로 들어갑니다. 원시 모드에서는, 일반 줄 버퍼링과 인터럽트, 종료, 일시 중단 및 흐름 제어 키 처리가 꺼집니다; curses 입력 함수로 문자가 한 번에 하나씩 제시됩니다.

curses.reset_prog_mode()

def_prog_mode()로 이전에 저장한 대로, 터미널을 “프로그램(program)” 모드로 복원합니다.

curses.reset_shell_mode()

def_shell_mode()로 이전에 저장한 대로, 터미널을 “셸(shell)” 모드로 복원합니다.

curses.resetty()

터미널 모드의 상태를 savetty()에 대한 마지막 호출 때의 상태로 복원합니다.

curses.resize_term(nlines, ncols)

resizeterm()이 사용하는 백 엔드 함수로, 대부분의 작업을 수행합니다; 창 크기를 조정할 때, resize_term()은 확장되는 영역을 공백으로 채웁니다. 호출하는 응용 프로그램은 이러한 영역을 적절한 데이터로 채워야 합니다. resize_term() 함수는 모든 창의 크기를 조정하려고 합니다. 그러나, 패드의 호출 규칙으로 인해, 응용 프로그램과의 추가 상호 작용 없이 이들의 크기를 조정할 수 없습니다.

curses.resizeterm(nlines, ncols)

표준과 현재 창의 크기를 지정된 크기로 조정하고, 창 크기를 기록하는 curses 라이브러리에서 사용하는 다른 관리 데이터를 조정합니다 (특히 SIGWINCH 처리기).

curses.savetty()

터미널 모드의 현재 상태를 resetty()에서 사용 가능한 버퍼에 저장합니다.

curses.get_escdelay()

set_escdelay()로 설정된 값을 가져옵니다.

Added in version 3.9.

curses.set_escdelay(ms)

키보드에 입력된 개별 이스케이프 문자와 커서와 기능키로 전송된 이스케이프 시퀀스를 구별하기 위해, 이스케이프 문자를 읽은 후 기다릴 밀리초 수를 설정합니다.

Added in version 3.9.

curses.get_tabsize()

set_tabsize()로 설정된 값을 가져옵니다.

Added in version 3.9.

curses.set_tabsize(size)

탭을 창에 추가해서 탭 문자를 스페이스로 변환할 때 curses 라이브러리가 사용하는 열 수를 설정합니다.

Added in version 3.9.

curses.setsyx(y, x)

가상 화면 커서를 y, x로 설정합니다. y와 x가 모두 -1이면, leaveok는 True로 설정됩니다.

curses.setupterm(term=None, fd=-1)

터미널을 초기화합니다. term은 터미널 이름을 제공하는 문자열이거나 None입니다; 생략되거나 None이면, TERM 환경 변수의 값이 사용됩니다. fd는 초기화 시퀀스가 전송될 파일 기술자입니다; 제공되지 않거나 -1이면, sys.stdout의 파일 기술자가 사용됩니다.

curses.start_color()

프로그래머가 색상을 사용하려면, 다른 색상 조작 루틴을 호출하기 전에 호출해야 합니다. initscr() 직후 이 루틴을 호출하는 것이 좋습니다.

start_color()는 8개의 기본 색상(검정, 빨강, 녹색, 노랑, 파랑, 마젠타, 시안 및 흰색)과 터미널이 지원할 수 있는 색상과 색상 쌍의 최댓값인 curses 모듈의 2개의 전역 변수 COLORS와 COLOR_PAIRS를 초기화합니다. 또한 터미널의 전원을 켰을 때의 값으로 터미널의 색상을 복원합니다.

curses.termattrs()

터미널이 지원하는 모든 비디오 속성의 논리적 OR를 반환합니다. 이 정보는 curses 프로그램이 화면 모양을 완전히 제어해야 할 때 유용합니다.

curses.termname()

환경 변수 TERM의 값을 14자로 잘린 바이트열 객체로 반환합니다.

curses.tigetflag(capname)

terminfo 기능 이름 capname에 해당하는 불리언 기능의 값을 정수로 반환합니다. capname이 불리언 기능이 아니면 -1 값을, 터미널 설명에서 취소되었거나 빠졌으면 0을 반환합니다.

curses.tigetnum(capname)

terminfo 기능 이름 capname에 해당하는 숫자 기능의 값을 정수로 반환합니다. capname이 숫자 기능이 아니면 -2 값을, 터미널 설명에서 취소되었거나 빠졌으면 -1을 반환합니다.

curses.tigetstr(capname)

terminfo 기능 이름 capname에 해당하는 문자열 기능의 값을 바이트열 객체로 반환합니다. capname이 terminfo “문자열 기능”이 아니거나, 터미널 설명에서 취소되었거나 빠졌으면 None을 반환합니다.

curses.tparm(str[, ...])

제공된 매개 변수를 사용하여 바이트열 객체 str을 인스턴스 화합니다. 여기서 str은 terminfo 데이터베이스에서 얻은 매개 변수화된 문자열이어야 합니다. 예를 들어 tparm(tigetstr("cup"), 5, 3)은 b'\033[6;4H'가 될 수 있습니다, 정확한 결과는 터미널 유형에 따라 다릅니다.

curses.typeahead(fd)

파일 기술자 fd가 선행 입력 검사(typeahead checking)에 사용되도록 지정합니다. fd가 -1이면, 선행 입력 검사가 수행되지 않습니다.

curses 라이브러리는 화면을 갱신하는 동안 정기적으로 선행 입력을 들여다보고 “라인 브레이크 아웃 최적화(line-breakout optimization)”를 수행합니다. 입력이 발견되고, 그것이 tty에서 왔으면, refresh나 doupdate가 다시 호출될 때까지 현재 갱신을 연기해서, 앞서 입력된 명령에 더 빠르게 응답 할 수 있도록 합니다. 이 함수를 사용하면 선행 입력 검사를 위해 다른 파일 기술자를 지정할 수 있습니다.

curses.unctrl(ch)

문자 ch의 인쇄 가능한 표현인 바이트열 객체를 반환합니다. 제어 문자는 캐럿과 그 뒤에 오는 문자로 표시됩니다, 예를 들어 b'^C'. 인쇄 문자는 그대로 남아 있습니다.

curses.ungetch(ch)

다음 getch()가 반환하도록 ch를 푸시합니다.

참고

getch()가 호출되기 전에 하나의 ch 만 푸시할 수 있습니다.

curses.update_lines_cols()

Update the LINES and COLS module variables. Useful for detecting manual screen resize.

Added in version 3.5.

curses.unget_wch(ch)

다음 get_wch()가 반환하도록 ch를 푸시합니다.

참고

get_wch()가 호출되기 전에 하나의 ch 만 푸시할 수 있습니다.

Added in version 3.3.

curses.ungetmouse(id, x, y, z, bstate)

주어진 상태 데이터와 결합하여, KEY_MOUSE 이벤트를 입력 큐로 푸시합니다.

curses.use_env(flag)

사용되면, 이 함수는 initscr()이나 newterm을 호출하기 전에 호출해야 합니다. flag가 False이면, 환경 변수 LINES와 COLUMNS(기본적으로 사용됩니다)가 설정되어 있거나, 창에서 curses가 실행 중인 경우(이때 기본 동작은 LINES와 COLUMNS가 설정되지 않았으면 창 크기를 사용하는 것입니다)에도 terminfo 데이터베이스에 지정된 행(lines)과 열(columns)의 값이 사용됩니다.

curses.use_default_colors()

이 기능을 지원하는 터미널에서 색상의 기본값을 사용하도록 허용합니다. 응용 프로그램에서 투명성을 지원하려면 이를 사용하십시오. 기본 색상은 색상 번호 -1에 할당됩니다. 이 함수를 호출하면, 예를 들어 init_pair(x, curses.COLOR_RED, -1)은 기본 배경 위의 빨간 전경색으로 색상 쌍 x를 초기화합니다.

curses.wrapper(func, /, *args, **kwargs)

curses를 초기화하고 다른 콜러블 객체 func를 호출하는데, 이 콜러블은 curses를 사용하는 응용 프로그램의 나머지 부분이어야 합니다. 응용 프로그램에서 예외가 발생하면, 이 함수는 예외를 다시 발생시키고 트레이스백을 생성하기 전에 터미널을 정상 상태로 복원합니다. 콜러블 객체 func는 메인 창 ‘stdscr’을 첫 번째 인자로 전달받고 wrapper()로 전달된 다른 모든 인자가 그 뒤를 따릅니다. func를 호출하기 전에, wrapper()는 cbreak 모드를 켜고, 반향을 끄고, 터미널 키패드를 활성화하고, 터미널에 색상이 지원되면 색상을 초기화합니다. 빠져나갈 때 (정상인지 예외로 인한 것인지 관계없이) 요리된(cooked) 모드를 복원하고, 반향을 켜고, 터미널 키패드를 비활성화합니다.

창 객체

위의 initscr()과 newwin()에 의해 반환된 창 객체에는 다음과 같은 메서드와 어트리뷰트가 있습니다:

window.addch(ch[, attr])

window.addch(y, x, ch[, attr])

속성 attr로 (y, x)에 문자 ch를 그려서, 그 위치에 이전에 그린 문자를 덮어씁니다. 기본적으로, 문자 위치와 속성은 창 객체의 현재 설정입니다.

참고

창, 하위 창(subwindow) 또는 패드 외부에 쓰면 curses.error가 발생합니다. 창, 하위 창 또는 패드의 오른쪽 하단에 쓰려고 하면 문자가 인쇄된 후 예외가 발생합니다.

window.addnstr(str, n[, attr])

window.addnstr(y, x, str, n[, attr])

(y, x)에 문자열 str의 최대 n 문자를 속성 attr로 그려, 이전 디스플레이의 내용을 덮어씁니다.

window.addstr(str[, attr])

window.addstr(y, x, str[, attr])

(y, x)에 문자열 str을 속성 attr로 그려, 이전 디스플레이의 내용을 덮어씁니다.

참고

창, 하위 창 또는 패드 외부에 쓰면 curses.error가 발생합니다. 창, 하위 창 또는 패드의 오른쪽 하단에 쓰려고 하면 문자열이 인쇄된 후 예외가 발생합니다.

이 파이썬 모듈의 백 엔드인 ncurses에 있는 버그 [https://bugs.python.org/issue35924]가 창 크기를 조정할 때 세그멘테이션 오류를 유발할 수 있습니다. 이것은 ncurses-6.1-20190511에서 수정되었습니다. 이전 ncurses에 갇혀 있다면, 줄 바꿈이 포함된 str로 addstr()을 호출하지 않으면 트리거를 피할 수 있습니다. 대신, 줄마다 addstr()을 따로 호출하십시오.

window.attroff(attr)

현재 창에 대한 모든 쓰기에 적용된 “배경(background)” 집합에서 속성 attr을 제거합니다.

window.attron(attr)

현재 창에 대한 모든 쓰기에 적용된 “배경(background)” 집합에 속성 attr을 추가합니다.

window.attrset(attr)

속성의 “배경(background)” 집합을 attr로 설정합니다. 이 집합은 처음에 0입니다 (속성 없음).

window.bkgd(ch[, attr])

창의 배경 속성을 attr 속성을 가진 문자 ch로 설정합니다. 그런 다음 해당 창의 모든 문자 위치에 변경 사항이 적용됩니다:

창의 모든 문자 속성이 새 배경 속성으로 변경됩니다.

이전 배경 문자가 나타날 때마다, 새 배경 문자로 변경됩니다.

window.bkgdset(ch[, attr])

창의 배경을 설정합니다. 창의 배경은 문자와 속성의 모든 조합으로 구성됩니다. 배경의 속성 부분은 창에 쓰인 모든 비 공백 문자와 결합(OR)합니다. 배경의 문자와 속성 부분은 모두 공백 문자와 결합합니다. 배경은 문자의 속성이 되고 스크롤과 줄/문자 삽입/삭제 연산을 통해 문자와 함께 이동합니다.

window.border([ls[, rs[, ts[, bs[, tl[, tr[, bl[, br]]]]]]]])

창의 가장자리 주위에 테두리를 그립니다. 각 매개 변수는 테두리의 특정 부분에 사용할 문자를 지정합니다; 자세한 내용은 아래 표를 참조하십시오.

참고

모든 매개 변수의 0 값은 해당 매개 변수에 기본 문자가 사용되도록 합니다. 키워드 매개 변수는 사용할 수 없습니다. 기본값은 이 표에 나열되어 있습니다:

매개 변수

설명

기본값

ls

좌변

ACS_VLINE

rs

우변

ACS_VLINE

ts

상단

ACS_HLINE

bs

하단

ACS_HLINE

tl

왼쪽 위 모서리

ACS_ULCORNER

tr

오른쪽 위 모서리

ACS_URCORNER

bl

왼쪽 아래 모서리

ACS_LLCORNER

br

오른쪽 아래 모서리

ACS_LRCORNER

window.box([vertch, horch])

border()와 유사하지만, ls와 rs가 모두 vertch이고 ts와 bs가 모두 horch입니다. 이 함수는 항상 기본 모서리 문자를 사용합니다.

window.chgat(attr)

window.chgat(num, attr)

window.chgat(y, x, attr)

window.chgat(y, x, num, attr)

현재 커서 위치나 제공되면 (y, x) 위치에 num 문자의 속성을 설정합니다. num이 제공되지 않거나 -1이면, 줄 끝까지의 모든 문자에 속성이 설정됩니다. 이 함수는 제공되면 커서를 (y, x) 위치로 이동합니다. 변경된 줄을 touchline() 메서드를 사용하여 터치해서 다음 창 refresh로 내용이 다시 표시됩니다.

window.clear()

erase()와 유사하지만, refresh()를 다음에 호출할 때 전체 창이 다시 그려집니다.

window.clearok(flag)

flag가 True이면, refresh()에 대한 다음 호출은 창을 완전히 지웁니다.

window.clrtobot()

커서에서 창끝까지 지웁니다: 커서 아래의 모든 줄이 삭제된 다음, clrtoeol()과 동등한 것이 수행됩니다.

window.clrtoeol()

커서에서 줄 끝까지 지웁니다.

window.cursyncup()

창의 현재 커서 위치를 반영하도록 창의 모든 조상의 현재 커서 위치를 갱신합니다.

window.delch([y, x])

(y, x)에서 문자를 삭제합니다.

window.deleteln()

커서 아래의 줄을 삭제합니다. 다음 줄은 모두 한 줄씩 위로 이동합니다.

window.derwin(begin_y, begin_x)

window.derwin(nlines, ncols, begin_y, begin_x)

“창 파생(derive window)”의 약어인 derwin()은 subwin()을 호출하는 것과 같지만, begin_y와 begin_x가 전체 화면에 상대적이 아니라 창의 원점에 상대적이라는 차이가 있습니다. 파생된 창에 대한 창 객체를 반환합니다.

window.echochar(ch[, attr])

attr 속성을 가진 문자 ch를 추가하고, 즉시 창에서 refresh()를 호출합니다.

window.enclose(y, x)

주어진 화면 상대적인 문자 셀 좌표 쌍이 주어진 창에 속하는지를 검사하고, True나 False를 반환합니다. 마우스 이벤트의 위치를 포함하는 화면 창의 부분 집합을 결정하는 데 유용합니다.

버전 3.10에서 변경: Previously it returned 1 or 0 instead of True or False.

window.encoding

Encoding used to encode method arguments (Unicode strings and characters). The encoding attribute is inherited from the parent window when a subwindow is created, for example with window.subwin(). By default, current locale encoding is used (see locale.getencoding()).

Added in version 3.3.

window.erase()

창을 지웁니다.

window.getbegyx()

Return a tuple (y, x) of coordinates of upper-left corner.

window.getbkgd()

주어진 창의 현재 배경 문자/속성 쌍을 반환합니다.

window.getch([y, x])

문자를 얻습니다. 반환된 정수는 ASCII 범위일 필요가 없음에 유의하십시오: 기능키, 키패드 키 등은 255보다 큰 숫자로 표시됩니다. 지연 없는(no-delay) 모드에서, 입력이 없으면 -1을 반환하고, 그렇지 않으면 키가 눌릴 때까지 기다립니다.

window.get_wch([y, x])

와이드 문자(wide character)를 얻습니다. 대부분의 키에 대해서는 문자를 반환하고, 기능키, 키패드 키 및 기타 특수키에 대해서는 정수를 반환합니다. 지연 없는(no-delay) 모드에서, 입력이 없으면 예외를 발생시킵니다.

Added in version 3.3.

window.getkey([y, x])

문자를 얻습니다. getch()처럼 정수를 반환하는 대신 문자열을 반환합니다. 기능키, 키패드 키 및 기타 특수키는 키 이름이 포함된 멀티 바이트 문자열을 반환합니다. 지연 없는(no-delay) 모드에서, 입력이 없으면 예외를 발생시킵니다.

window.getmaxyx()

창의 높이와 너비의 튜플 (y, x)를 반환합니다.

window.getparyx()

부모 창에 대해 상대적인 이 창의 시작 좌표를 튜플 (y, x)로 반환합니다. 이 창에 부모가 없으면 (-1, -1)을 반환합니다.

window.getstr()

window.getstr(n)

window.getstr(y, x)

window.getstr(y, x, n)

프리미티브 줄 편집 용량으로, 사용자로부터 바이트열 객체를 읽습니다.

window.getyx()

창의 왼쪽 위 모서리에 상대적인 현재 커서 위치의 튜플 (y, x)를 반환합니다.

window.hline(ch, n)

window.hline(y, x, ch, n)

문자 ch로 구성된 길이 n의 (y, x)에서 시작하는 수평선을 표시합니다.

window.idcok(flag)

flag가 False이면, curses는 더는 터미널의 하드웨어 문자 삽입/삭제 기능 사용을 고려하지 않습니다; flag가 True이면, 문자 삽입과 삭제 사용이 활성화됩니다. curses가 처음 초기화될 때, 기본적으로 문자 삽입/삭제 사용이 활성화됩니다.

window.idlok(flag)

flag가 True이면, curses는 하드웨어 줄 편집 기능을 시도하고 사용합니다. 그렇지 않으면, 줄 삽입/삭제가 비활성화됩니다.

window.immedok(flag)

flag가 True이면, 창 이미지의 모든 변경이 자동으로 창을 새로 고칩니다; 더는 refresh()를 직접 호출할 필요가 없습니다. 그러나, wrefresh 호출이 반복되어, 성능이 크게 저하될 수 있습니다. 이 옵션은 기본적으로 비활성화되어 있습니다.

window.inch([y, x])

창의 주어진 위치에 있는 문자를 반환합니다. 하위 8비트는 문자이고, 상위 비트는 속성입니다.

window.insch(ch[, attr])

window.insch(y, x, ch[, attr])

속성 attr로 (y, x)에 문자 ch를 그리면서, x 위치에서 한 문자씩 오른쪽으로 줄을 이동합니다.

window.insdelln(nlines)

현재 줄 위의 지정된 창에 nlines 줄을 삽입합니다. nlines 바닥 줄은 손실됩니다. 음의 nlines의 경우, 커서 아래에 있는 줄에서 시작하여 nlines 줄을 삭제하고, 나머지 줄을 위로 이동합니다. 바닥 nlines 줄이 지워집니다. 현재 커서 위치는 같게 유지됩니다.

window.insertln()

커서 아래에 빈 줄을 삽입합니다. 그다음 모든 줄은 한 줄 아래로 이동합니다.

window.insnstr(str, n[, attr])

window.insnstr(y, x, str, n[, attr])

커서 아래의 문자 앞에 최대 n 문자까지 문자열(줄에 맞는 최대 문자)을 삽입합니다. n이 0이거나 음수이면, 전체 문자열이 삽입됩니다. 커서 오른쪽의 모든 문자가 오른쪽으로 이동하고, 줄의 가장 오른쪽 문자들이 손실됩니다. 커서 위치는 변경되지 않습니다 (지정되면, y, x로 이동한 후에).

window.insstr(str[, attr])

window.insstr(y, x, str[, attr])

커서 아래의 문자 앞에 문자열(줄에 맞는 최대 문자)을 삽입합니다. 커서 오른쪽의 모든 문자가 오른쪽으로 이동하고, 줄의 가장 오른쪽 문자들이 손실됩니다. 커서 위치는 변경되지 않습니다 (지정되면, y, x로 이동한 후에).

window.instr([n])

window.instr(y, x[, n])

현재 커서 위치에서 시작하거나 지정되면 y, x에서 시작하여 창에서 추출된 문자의 바이트열 객체를 반환합니다. 문자에서 속성이 제거됩니다. n이 지정되면, instr()은 최대 n 문자의 문자열을 반환합니다 (끝의 NUL은 제외합니다).

window.is_linetouched(line)

refresh()에 대한 마지막 호출 이후 지정된 줄이 수정되었으면 True를 반환합니다; 그렇지 않으면 False를 반환합니다. 주어진 창에서 line이 유효하지 않으면 curses.error 예외를 발생시킵니다.

window.is_wintouched()

refresh()에 대한 마지막 호출 이후 지정된 창이 수정되었으면 True를 반환합니다; 그렇지 않으면 False를 반환합니다.

window.keypad(flag)

flag가 True이면, 일부 키(키패드, 기능키)가 생성한 이스케이프 시퀀스를 curses가 해석합니다. flag가 False이면, 이스케이프 시퀀스는 입력 스트림에 그대로 남아 있습니다.

window.leaveok(flag)

flag가 True이면, 커서는 “커서 위치”가 아니라 갱신 중인 위치에 남아 있습니다. 가능하면 커서 이동이 줄어듭니다. 가능하면 커서가 보이지 않게 합니다.

flag가 False이면, 커서는 갱신 후 항상 “커서 위치”에 있게 됩니다.

window.move(new_y, new_x)

커서를 (new_y, new_x)로 이동합니다.

window.mvderwin(y, x)

창을 부모 창 내부로 이동합니다. 창의 화면에 상대적인 매개 변수는 변경되지 않습니다. 이 루틴은 부모 창의 다른 부분을 화면에서 같은 물리적 위치에 표시하는 데 사용됩니다.

window.mvwin(new_y, new_x)

왼쪽 위 모서리가 (new_y, new_x)가 되도록 창을 이동합니다.

window.nodelay(flag)

flag가 True이면, getch()가 비 블로킹이 됩니다.

window.notimeout(flag)

flag가 True이면, 이스케이프 시퀀스가 시간 초과하지 않습니다.

flag가 False이면, 몇 밀리초 후에, 이스케이프 시퀀스가 해석되지 않고, 그대로 입력 스트림에 남아 있습니다.

window.noutrefresh()

새로 고침을 표시하지만 기다립니다. 이 함수는 원하는 창의 상태를 나타내는 데이터 구조를 갱신하지만, 물리적 화면을 강제로 갱신하지는 않습니다. 이를 위해서는, doupdate()를 호출하십시오.

window.overlay(destwin[, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol])

destwin 위에 창을 오버레이 합니다. 창의 크기가 같을 필요는 없으며, 겹치는 영역만 복사됩니다. 이 복사는 비 파괴적인데, 현재 배경 문자가 destwin의 이전 내용을 덮어쓰지 않습니다.

복사되는 영역을 세밀하게 제어하기 위해, overlay()의 두 번째 형식을 사용할 수 있습니다. sminrow와 smincol은 소스 창의 왼쪽 위 좌표이며, 다른 변수들은 대상 창의 사각형을 표시합니다.

window.overwrite(destwin[, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol])

destwin 위에 창을 덮어씁니다. 창의 크기가 같을 필요는 없으며, 이 경우 겹치는 영역만 복사됩니다. 이 복사는 파괴적인데, 현재 배경 문자가 destwin의 이전 내용을 덮어씁니다.

복사된 영역을 세밀하게 제어하기 위해, overwrite()의 두 번째 형식을 사용할 수 있습니다. sminrow와 smincol은 소스 창의 왼쪽 위 좌표이며, 다른 변수들은 대상 창의 사각형을 표시합니다.

window.putwin(file)

창과 연관된 모든 데이터를 제공된 파일 객체에 기록합니다. 이 정보는 나중에 getwin() 함수를 사용하여 가져올 수 있습니다.

window.redrawln(beg, num)

beg 줄에서 시작하는 num 화면 줄이 손상되었으며 다음 refresh() 호출에서 완전히 다시 그려야 함을 나타냅니다.

window.redrawwin()

전체 창을 터치하여, 다음 refresh() 호출에서 완전히 다시 그려지도록 합니다.

window.refresh([pminrow, pmincol, sminrow, smincol, smaxrow, smaxcol])

화면을 즉시 갱신합니다 (이전 그리기/삭제 메서드와 실제 화면을 동기화합니다).

6개의 선택적 인자는 창이 newpad()로 만들어진 패드일 때만 지정할 수 있습니다. 추가 매개 변수는 패드와 화면의 어떤 부분이 관련되어 있는지를 나타내기 위해 필요합니다. pminrow와 pmincol은 패드에서 표시할 사각형의 왼쪽 위 모서리를 지정합니다. sminrow, smincol, smaxrow 및 smaxcol은 화면에 표시할 사각형의 변을 지정합니다. 사각형의 크기가 같아야 해서, 패드에서 표시할 사각형의 오른쪽 아래 모서리는 화면 좌표에서 계산됩니다. 두 사각형 모두 해당 구조 내에 완전히 포함되어야 합니다. pminrow, pmincol, sminrow 또는 smincol의 음수 값은 마치 0인 것처럼 처리됩니다.

window.resize(nlines, ncols)

curses 창의 스토리지를 재할당하여 지정된 값으로 크기를 조정합니다. 두 크기 중 하나가 현재 값보다 크면, 창의 데이터는 현재 배경 변환 (bkgdset()으로 설정한)을 갖는 공백으로 채워집니다.

window.scroll([lines=1])

화면이나 스크롤 영역을 lines 줄 위로 스크롤 합니다.

window.scrollok(flag)

맨 아래 줄에서의 줄 바꾸기나 마지막 줄의 마지막 문자 입력의 결과로, 창의 커서가 창이나 스크롤 영역의 경계를 벗어날 때 어떻게 할지를 제어합니다. flag가 False이면, 맨 아래 줄에 남습니다. flag가 True이면, 창은 한 줄 위로 스크롤 됩니다. 터미널에서 물리적 스크롤 효과를 얻으려면, idlok()도 호출해야 함에 유의하십시오.

window.setscrreg(top, bottom)

스크롤 영역을 top 줄에서 bottom 줄로 설정합니다. 모든 스크롤 작업은 이 영역에서 수행됩니다.

window.standend()

스탠드 아웃(standout) 속성을 끕니다. 일부 터미널에서는 모든 속성을 끄는 부작용이 있습니다.

window.standout()

속성 A_STANDOUT을 켭니다.

window.subpad(begin_y, begin_x)

window.subpad(nlines, ncols, begin_y, begin_x)

왼쪽 위 모서리가 (begin_y, begin_x)이고, 너비/높이가 ncols/nlines인 서브 창을 반환합니다.

window.subwin(begin_y, begin_x)

window.subwin(nlines, ncols, begin_y, begin_x)

왼쪽 위 모서리가 (begin_y, begin_x)이고, 너비/높이가 ncols/nlines인 서브 창을 반환합니다.

기본적으로, 서브 창은 지정된 위치에서 창의 오른쪽 아래 모서리에 이릅니다.

window.syncdown()

조상 창에서 터치된 창의 각 위치를 터치합니다. 이 루틴은 refresh()에 의해 호출되므로, 수동으로 호출할 필요가 거의 없습니다.

window.syncok(flag)

flag가 True이면, 창에 변경 사항이 있을 때마다 syncup()이 자동으로 호출됩니다.

window.syncup()

창에서 변경된 창 조상의 모든 위치를 터치합니다.

window.timeout(delay)

창의 블로킹이나 비 블로킹 읽기 동작을 설정합니다. delay가 음수이면, 블로킹 읽기가 사용됩니다 (입력을 무한정 기다립니다). delay가 0이면, 비 블로킹 읽기가 사용되며, 대기 중인 입력이 없으면 getch()는 -1을 반환합니다. delay가 양수이면, getch()는 delay 밀리초 동안 블록 하고, 해당 시간이 지나도 여전히 입력이 없으면 -1을 반환합니다.

window.touchline(start, count[, changed])

줄 start로 시작하여 count 줄이 변경된 것으로 가정합니다. changed가 제공되면, 영향을 받는 줄이 변경되었다고 (changed=True) 또는 변경되지 않았다고 (changed=False) 표시할지를 지정합니다.

window.touchwin()

그리기 최적화를 위해, 전체 창이 변경된 것으로 가정합니다.

window.untouchwin()

refresh()를 마지막으로 호출한 후에 창의 모든 줄을 변경되지 않은 것으로 표시합니다.

window.vline(ch, n[, attr])

window.vline(y, x, ch, n[, attr])

Display a vertical line starting at (y, x) with length n consisting of the character ch with attributes attr.

상수

curses 모듈은 다음 데이터 멤버를 정의합니다:

curses.ERR

정수를 반환하는 일부 curses 루틴은 (가령 getch()) 실패 시 ERR을 반환합니다.

curses.OK

정수를 반환하는 일부 curses 루틴은 (가령 napms()) 성공 시 OK를 반환합니다.

curses.version

curses.__version__

A bytes object representing the current version of the module.

curses.ncurses_version

ncurses 라이브러리 버전의 세 가지 구성 요소를 포함하는 네임드 튜플: major, minor 및 patch. 모든 값은 정수입니다. 구성 요소는 이름으로도 액세스 할 수 있어서, curses.ncurses_version[0]은 curses.ncurses_version.major와 동등합니다.

가용성: ncurses 라이브러리가 사용된 경우.

Added in version 3.8.

curses.COLORS

The maximum number of colors the terminal can support. It is defined only after the call to start_color().

curses.COLOR_PAIRS

The maximum number of color pairs the terminal can support. It is defined only after the call to start_color().

curses.COLS

The width of the screen, i.e., the number of columns. It is defined only after the call to initscr(). Updated by update_lines_cols(), resizeterm() and resize_term().

curses.LINES

The height of the screen, i.e., the number of lines. It is defined only after the call to initscr(). Updated by update_lines_cols(), resizeterm() and resize_term().

문자 셀 속성을 지정하기 위해 일부 상수를 사용할 수 있습니다. 사용 가능한 정확한 상수는 시스템에 따라 다릅니다.

속성

의미

curses.A_ALTCHARSET

대체 문자 집합 모드

curses.A_BLINK

깜박임 모드

curses.A_BOLD

볼드 모드

curses.A_DIM

희미한 모드

curses.A_INVIS

보이지 않거나 공백 모드

curses.A_ITALIC

기울임 꼴 모드

curses.A_NORMAL

일반 속성

curses.A_PROTECT

보호 모드

curses.A_REVERSE

배경과 전경색 반전

curses.A_STANDOUT

눈에 띄는 모드

curses.A_UNDERLINE

밑줄 모드

curses.A_HORIZONTAL

수평 하이라이트

curses.A_LEFT

왼쪽 하이라이트

curses.A_LOW

낮은 하이라이트

curses.A_RIGHT

오른쪽 하이라이트

curses.A_TOP

상단 하이라이트

curses.A_VERTICAL

수직 하이라이트

Added in version 3.7: A_ITALIC이 추가되었습니다.

일부 메서드에서 반환한 해당 속성을 추출하기 위해 여러 상수를 사용할 수 있습니다.

비트 마스크

의미

curses.A_ATTRIBUTES

속성을 추출하는 비트 마스크

curses.A_CHARTEXT

문자를 추출하는 비트 마스크

curses.A_COLOR

색상 쌍 필드 정보를 추출하는 비트 마스크

키는 KEY_로 시작하는 이름을 가진 정수 상수로 참조됩니다. 사용 가능한 정확한 키 기능은 시스템에 따라 다릅니다.

키 상수

키

curses.KEY_MIN

최소 키값

curses.KEY_BREAK

브레이크 키 (신뢰할 수 없습니다)

curses.KEY_DOWN

아래쪽 화살표

curses.KEY_UP

위쪽 화살표

curses.KEY_LEFT

왼쪽 화살표

curses.KEY_RIGHT

오른쪽 화살표

curses.KEY_HOME

홈 키 (위쪽+왼쪽 화살표)

curses.KEY_BACKSPACE

백스페이스 (신뢰할 수 없습니다)

curses.KEY_F0

기능키. 최대 64개의 기능키가 지원됩니다.

curses.KEY_Fn

기능키 n의 값

curses.KEY_DL

줄 삭제

curses.KEY_IL

줄 삽입

curses.KEY_DC

문자 삭제

curses.KEY_IC

문자 삽입이나 삽입 모드로 들어가기

curses.KEY_EIC

문자 삽입 모드 종료

curses.KEY_CLEAR

화면 지우기

curses.KEY_EOS

화면 끝까지 지우기

curses.KEY_EOL

줄 끝까지 지우기

curses.KEY_SF

한 줄 앞으로 스크롤

curses.KEY_SR

한 줄 뒤로 스크롤 (역)

curses.KEY_NPAGE

다음 페이지

curses.KEY_PPAGE

이전 페이지

curses.KEY_STAB

탭 설정

curses.KEY_CTAB

탭 지우기

curses.KEY_CATAB

모든 탭 지우기

curses.KEY_ENTER

엔터나 발송 (신뢰할 수 없습니다)

curses.KEY_SRESET

소프트(soft) (부분) 재설정 (신뢰할 수 없습니다)

curses.KEY_RESET

재설정이나 하드(hard) 재설정 (신뢰할 수 없습니다)

curses.KEY_PRINT

인쇄

curses.KEY_LL

홈 다운이나 바닥 (왼쪽 아래)

curses.KEY_A1

키패드의 왼쪽 위

curses.KEY_A3

키패드의 오른쪽 위

curses.KEY_B2

키패드 가운데

curses.KEY_C1

키패드의 왼쪽 아래

curses.KEY_C3

키패드의 오른쪽 아래

curses.KEY_BTAB

백 탭

curses.KEY_BEG

Beg (시작)

curses.KEY_CANCEL

취소

curses.KEY_CLOSE

닫기

curses.KEY_COMMAND

Cmd (명령)

curses.KEY_COPY

복사

curses.KEY_CREATE

생성

curses.KEY_END

끝

curses.KEY_EXIT

종료

curses.KEY_FIND

찾기

curses.KEY_HELP

도움말

curses.KEY_MARK

표시

curses.KEY_MESSAGE

메시지

curses.KEY_MOVE

이동

curses.KEY_NEXT

다음

curses.KEY_OPEN

열기

curses.KEY_OPTIONS

옵션

curses.KEY_PREVIOUS

Prev (이전)

curses.KEY_REDO

다시 하기

curses.KEY_REFERENCE

Ref (참조)

curses.KEY_REFRESH

새로 고침

curses.KEY_REPLACE

교체

curses.KEY_RESTART

재시작

curses.KEY_RESUME

재개

curses.KEY_SAVE

저장

curses.KEY_SBEG

시프트 Beg (시작)

curses.KEY_SCANCEL

시프트 취소

curses.KEY_SCOMMAND

시프트 명령

curses.KEY_SCOPY

시프트 복사

curses.KEY_SCREATE

시프트 생성

curses.KEY_SDC

시프트 문자 삭제

curses.KEY_SDL

시프트 줄 삭제

curses.KEY_SELECT

선택

curses.KEY_SEND

시프트 끝

curses.KEY_SEOL

시프트 줄 지우기

curses.KEY_SEXIT

시프트 종료

curses.KEY_SFIND

시프트 찾기

curses.KEY_SHELP

시프트 도움말

curses.KEY_SHOME

시프트 홈

curses.KEY_SIC

시프트 입력

curses.KEY_SLEFT

시프트 왼쪽 화살표

curses.KEY_SMESSAGE

시프트 메시지

curses.KEY_SMOVE

시프트 이동

curses.KEY_SNEXT

시프트 다음

curses.KEY_SOPTIONS

시프트 옵션

curses.KEY_SPREVIOUS

시프트 Prev

curses.KEY_SPRINT

시프트 인쇄

curses.KEY_SREDO

시프트 다시 하기

curses.KEY_SREPLACE

시프트 교체

curses.KEY_SRIGHT

시프트 오른쪽 화살표

curses.KEY_SRSUME

시프트 재개

curses.KEY_SSAVE

시프트 저장

curses.KEY_SSUSPEND

시프트 일시 중단

curses.KEY_SUNDO

시프트 실행 취소

curses.KEY_SUSPEND

일시 중단

curses.KEY_UNDO

실행 취소

curses.KEY_MOUSE

마우스 이벤트가 발생했습니다

curses.KEY_RESIZE

터미널 크기 조정 이벤트

curses.KEY_MAX

최대 키값

On VT100s and their software emulations, such as X terminal emulators, there are normally at least four function keys (KEY_F1, KEY_F2, KEY_F3, KEY_F4) available, and the arrow keys mapped to KEY_UP, KEY_DOWN, KEY_LEFT and KEY_RIGHT in the obvious way. If your machine has a PC keyboard, it is safe to expect arrow keys and twelve function keys (older PC keyboards may have only ten function keys); also, the following keypad mappings are standard:

키 기능

상수

Insert

KEY_IC

Delete

KEY_DC

Home

KEY_HOME

End

KEY_END

Page Up

KEY_PPAGE

Page Down

KEY_NPAGE

다음 표는 대체 문자 집합의 문자를 나열합니다. 이들은 VT100 터미널에서 상속되며, 일반적으로 X 터미널과 같은 소프트웨어 에뮬레이션에서 사용할 수 있습니다. 사용 가능한 그래픽이 없으면, curses는 조잡한 인쇄 가능한 ASCII 근사치로 폴 백 합니다.

참고

initscr()가 호출된 후에만 사용할 수 있습니다.

ACS 코드

의미

curses.ACS_BBSS

오른쪽 위 모서리의 대체 이름

curses.ACS_BLOCK

채워진 사각형 블록

curses.ACS_BOARD

사각형의 보드

curses.ACS_BSBS

수평선의 대체 이름

curses.ACS_BSSB

왼쪽 위 모서리의 대체 이름

curses.ACS_BSSS

상단 티(top tee)의 대체 이름

curses.ACS_BTEE

하단 티(bottom tee)

curses.ACS_BULLET

불릿

curses.ACS_CKBOARD

체커 보드 (점각)

curses.ACS_DARROW

아래쪽을 가리키는 화살표

curses.ACS_DEGREE

디그리 기호

curses.ACS_DIAMOND

다이아몬드

curses.ACS_GEQUAL

크거나 같음

curses.ACS_HLINE

수평선

curses.ACS_LANTERN

랜턴 기호

curses.ACS_LARROW

왼쪽 화살표

curses.ACS_LEQUAL

작거나 같음

curses.ACS_LLCORNER

왼쪽 아래 모서리

curses.ACS_LRCORNER

오른쪽 아래 모서리

curses.ACS_LTEE

왼쪽 티(left tee)

curses.ACS_NEQUAL

같지 않음 기호

curses.ACS_PI

글자 파이(pi)

curses.ACS_PLMINUS

더하기-또는-빼기 기호

curses.ACS_PLUS

큰 더하기 기호

curses.ACS_RARROW

오른쪽 화살표

curses.ACS_RTEE

오른쪽 티(right tee)

curses.ACS_S1

스캔 줄 1

curses.ACS_S3

스캔 줄 3

curses.ACS_S7

스캔 줄 7

curses.ACS_S9

스캔 줄 9

curses.ACS_SBBS

오른쪽 아래 모서리의 대체 이름

curses.ACS_SBSB

세로줄의 대체 이름

curses.ACS_SBSS

오른쪽 티의 대체 이름

curses.ACS_SSBB

왼쪽 아래 모서리의 대체 이름

curses.ACS_SSBS

하단 티의 대체 이름

curses.ACS_SSSB

왼쪽 티의 대체 이름

curses.ACS_SSSS

크로스 오버(crossover) 또는 큰 더하기의 대체 이름

curses.ACS_STERLING

파운드 스털링(pound sterling)

curses.ACS_TTEE

상단 티(top tee)

curses.ACS_UARROW

위쪽 화살표

curses.ACS_ULCORNER

왼쪽 위 모서리

curses.ACS_URCORNER

오른쪽 위 모서리

curses.ACS_VLINE

수직선

The following table lists mouse button constants used by getmouse():

Mouse button constant

의미

curses.BUTTONn_PRESSED

Mouse button n pressed

curses.BUTTONn_RELEASED

Mouse button n released

curses.BUTTONn_CLICKED

Mouse button n clicked

curses.BUTTONn_DOUBLE_CLICKED

Mouse button n double clicked

curses.BUTTONn_TRIPLE_CLICKED

Mouse button n triple clicked

curses.BUTTON_SHIFT

Shift was down during button state change

curses.BUTTON_CTRL

Control was down during button state change

curses.BUTTON_ALT

Control was down during button state change

버전 3.10에서 변경: The BUTTON5_* constants are now exposed if they are provided by the underlying curses library.

다음 표는 사전 정의된 색상을 나열합니다:

상수

색상

curses.COLOR_BLACK

검은색

curses.COLOR_BLUE

파랑

curses.COLOR_CYAN

시안 (청록색 - 밝은 초록이 섞인 파랑)

curses.COLOR_GREEN

초록

curses.COLOR_MAGENTA

마젠타 (자홍색)

curses.COLOR_RED

빨강

curses.COLOR_WHITE

흰색

curses.COLOR_YELLOW

노랑

curses.textpad — curses 프로그램을 위한 텍스트 입력 위젯

curses.textpad 모듈은 curses 창에서 기본 텍스트 편집을 처리하는 Textbox 클래스를 제공하며, Emacs와 유사한 일련의 키 바인딩을 지원합니다 (따라서 Netscape Navigator, BBedit 6.x, FrameMaker 및 기타 여러 프로그램과도 유사한). 이 모듈은 텍스트 상자의 틀이나 다른 목적에 유용한 사각형 그리기 함수도 제공합니다.

curses.textpad 모듈은 다음 함수를 정의합니다:

curses.textpad.rectangle(win, uly, ulx, lry, lrx)

직사각형을 그립니다. 첫 번째 인자는 창 객체여야 합니다; 나머지 인자는 그 창에 상대적인 좌표입니다. 두 번째와 세 번째 인자는 그릴 사각형의 왼쪽 위 모서리의 y와 x 좌표입니다; 네 번째와 다섯 번째 인자는 오른쪽 아래 모서리의 y와 x 좌표입니다. 사각형은 이것이 가능한 터미널(xterm과 대부분의 다른 소프트웨어 터미널 에뮬레이터를 포함합니다)에서 VT100/IBM PC 양식 문자를 사용하여 그려집니다. 그렇지 않으면 ASCII 대시, 세로 막대 및 더하기 기호로 그려집니다.

Textbox 객체

다음과 같이 Textbox 객체를 인스턴스 화 할 수 있습니다:

class curses.textpad.Textbox(win)

텍스트 상자 위젯 객체를 반환합니다. win 인자는 텍스트 상자가 포함될 curses 창 객체여야 합니다. 텍스트 상자의 편집 커서는 처음에 좌표 (0, 0)으로 포함하는 창의 왼쪽 위 모서리에 있습니다. 인스턴스의 stripspaces 플래그가 처음에 켜집니다.

Textbox 객체에는 다음과 같은 메서드가 있습니다:

edit([validator])

이것이 일반적으로 사용하는 진입점입니다. 종료 키 입력 중 하나를 입력할 때까지 편집 키 입력을 받아들입니다. validator가 제공되면, 반드시 함수여야 합니다. 입력한 각 키 입력에 대해 키 입력을 매개 변수로 호출됩니다; 명령 디스패치가 그 결과에 대해 수행됩니다. 이 메서드는 창 내용을 문자열로 반환합니다; 창의 공백이 포함되는지는 stripspaces 어트리뷰트의 영향을 받습니다.

do_command(ch)

단일 명령 키 입력을 처리합니다. 지원되는 특수키 입력은 다음과 같습니다:

키 입력

동작

Control-A

창의 왼쪽 가장자리로 이동합니다.

Control-B

커서를 왼쪽으로 옮깁니다, 필요하면 앞줄로 넘어갑니다.

Control-D

커서 아래의 문자를 삭제합니다.

Control-E

오른쪽 가장자리(stripspaces가 꺼졌을 때)나 줄 끝(stripspaces가 켜졌을 때)으로 이동합니다.

Control-F

커서를 오른쪽으로 옮깁니다, 필요하면 다음 줄로 넘어갑니다.

Control-G

종료하고, 창 내용을 반환합니다.

Control-H

문자를 뒤로 삭제합니다.

Control-J

창이 한 줄이면 종료하고, 그렇지 않으면 줄 바꿈을 삽입합니다.

Control-K

줄이 비어 있으면, 삭제하고, 그렇지 않으면 줄 끝까지 지웁니다.

Control-L

화면을 새로 고칩니다.

Control-N

커서를 아래로 옮깁니다; 한 줄 아래로 이동합니다.

Control-O

커서 위치에 빈 줄을 삽입합니다.

Control-P

커서를 위로 옮깁니다; 한 줄 위로 이동합니다.

이동이 불가능한 가장자리에 커서가 있으면 이동 연산이 수행되지 않습니다. 가능하면 다음 동의어가 지원됩니다:

상수

키 입력

KEY_LEFT

Control-B

KEY_RIGHT

Control-F

KEY_UP

Control-P

KEY_DOWN

Control-N

KEY_BACKSPACE

Control-h

다른 모든 키 입력은 주어진 문자를 삽입하고 (줄 넘김을 포함한) 오른쪽으로 이동하는 명령으로 처리됩니다.

gather()

창 내용을 문자열로 반환합니다; 창의 공백이 포함되는지는 stripspaces 멤버의 영향을 받습니다.

stripspaces

이 어트리뷰트는 창의 공백 해석을 제어하는 플래그입니다. 켜져 있으면, 각 줄의 후행 공백이 무시됩니다; 후행 공백에 커서를 놓는 커서 동작은 대신 해당 줄의 끝으로 이동하고, 창 내용이 수집될 때 후행 공백이 제거됩니다.

curses.ascii — Utilities for ASCII characters

Source code: Lib/curses/ascii.py [https://github.com/python/cpython/tree/main/Lib/curses/ascii.py]

curses.ascii 모듈은 ASCII 문자에 대한 이름 상수와 다양한 ASCII 문자 클래스에서 멤버십을 검사하는 함수를 제공합니다. 제공된 상수는 다음과 같이 제어 문자의 이름입니다:

이름

의미

curses.ascii.NUL

curses.ascii.SOH

헤딩의 시작(Start of heading), 콘솔 인터럽트

curses.ascii.STX

텍스트의 시작(Start of text)

curses.ascii.ETX

텍스트 끝(End of text)

curses.ascii.EOT

전송 끝(End of transmission)

curses.ascii.ENQ

문의(Enquiry), ACK 흐름 제어와 함께 제공

curses.ascii.ACK

확인(Acknowledgement)

curses.ascii.BEL

벨(Bell)

curses.ascii.BS

백스페이스(Backspace)

curses.ascii.TAB

탭(Tab)

curses.ascii.HT

TAB의 별칭: “가로 탭(Horizontal tab)”

curses.ascii.LF

줄 바꿈(Line feed)

curses.ascii.NL

LF의 별칭: “새 줄(New line)”

curses.ascii.VT

세로 탭(Vertical tab)

curses.ascii.FF

용지 공급(Form feed)

curses.ascii.CR

캐리지 리턴(Carriage return)

curses.ascii.SO

시프트 아웃(Shift-out), 대체 문자 집합 시작

curses.ascii.SI

시프트 인(Shift-in), 기본 문자 집합 재개

curses.ascii.DLE

데이터 링크 이스케이프(Data-link escape)

curses.ascii.DC1

XON, 흐름 제어용

curses.ascii.DC2

장치 제어(Device control) 2, 블록 모드 흐름 제어

curses.ascii.DC3

XOFF, 흐름 제어용

curses.ascii.DC4

장치 제어(Device control) 4

curses.ascii.NAK

부정적 확인(Negative acknowledgement)

curses.ascii.SYN

동기 대기(Synchronous idle)

curses.ascii.ETB

전송 블록 종료(End transmission block)

curses.ascii.CAN

취소(Cancel)

curses.ascii.EM

매체의 끝(End of medium)

curses.ascii.SUB

치환(Substitute)

curses.ascii.ESC

탈출(Escape)

curses.ascii.FS

파일 구분자(File separator)

curses.ascii.GS

그룹 구분자(Group separator)

curses.ascii.RS

레코드 구분자(Record separator), 블록 모드 종료자

curses.ascii.US

단위 구분자(Unit separator)

curses.ascii.SP

스페이스(Space)

curses.ascii.DEL

삭제(Delete)

이들 중 많은 것들이 현대적인 사용법에서 실질적인 중요성을 거의 가지고 있지 않습니다. 니모닉은 디지털 컴퓨터 이전의 텔레 프린터 규칙에서 파생되었습니다.

이 모듈은 표준 C 라이브러리의 함수에 따라 다음 함수를 제공합니다:

curses.ascii.isalnum(c)

ASCII 영숫자를 확인합니다; isalpha(c) or isdigit(c)와 동등합니다.

curses.ascii.isalpha(c)

ASCII 알파벳 문자를 확인합니다. isupper(c) or islower(c)와 동등합니다.

curses.ascii.isascii(c)

7비트 ASCII 집합에 맞는 문자 값을 확인합니다.

curses.ascii.isblank(c)

ASCII 공백 문자를 확인합니다; 스페이스나 가로 탭.

curses.ascii.iscntrl(c)

ASCII 제어 문자를 확인합니다 (0x00에서 0x1f 범위에 있거나 0x7f).

curses.ascii.isdigit(c)

ASCII 십진 숫자, '0' 에서 '9'를 확인합니다. 이것은 c in string.digits와 동등합니다.

curses.ascii.isgraph(c)

스페이스를 제외한 인쇄 가능한 ASCII 문자를 확인합니다.

curses.ascii.islower(c)

ASCII 소문자를 확인합니다.

curses.ascii.isprint(c)

스페이스를 포함하여 인쇄 가능한 ASCII 문자를 확인합니다.

curses.ascii.ispunct(c)

스페이스나 영숫자가 아닌 인쇄 가능한 ASCII 문자를 확인합니다.

curses.ascii.isspace(c)

ASCII 공백 문자를 확인합니다; 스페이스, 줄 바꿈, 캐리지 리턴, 용지 공급, 가로 탭, 세로 탭.

curses.ascii.isupper(c)

ASCII 대문자를 확인합니다.

curses.ascii.isxdigit(c)

ASCII 16진수를 확인합니다. 이것은 c in string.hexdigits와 동등합니다.

curses.ascii.isctrl(c)

ASCII 제어 문자를 확인합니다 (정숫값 0에서 31).

curses.ascii.ismeta(c)

비 ASCII 문자를 확인합니다 (0x80 이상의 정수 값).

이 함수는 정수나 단일 문자 문자열을 받아들입니다; 인자가 문자열이면, 내장 함수 ord()를 사용하여 먼저 변환됩니다.

이 모든 함수는 전달한 문자열의 문자에서 파생된 서수 비트 값을 확인합니다; 호스트 기계의 문자 인코딩에 대해서는 실제로 아무것도 모릅니다.

다음 두 함수는 단일 문자 문자열이나 정수 바이트 값을 취합니다; 이들은 같은 유형의 값을 반환합니다.

curses.ascii.ascii(c)

c의 하위 7비트에 해당하는 ASCII 값을 반환합니다.

curses.ascii.ctrl(c)

주어진 문자에 해당하는 제어 문자를 반환합니다 (문자 비트 값은 0x1f와 비트별 and 됩니다).

curses.ascii.alt(c)

주어진 ASCII 문자에 해당하는 8비트 문자를 반환합니다 (문자 비트 값은 0x80과 비트별 or 됩니다).

다음 함수는 단일 문자 문자열이나 정숫값을 취합니다; 문자열을 반환합니다.

curses.ascii.unctrl(c)

ASCII 문자 c의 문자열 표현을 반환합니다. c가 인쇄 가능하면, 이 문자열은 문자 자체입니다. 문자가 제어 문자(0x00–0x1f)이면 문자열은 캐럿('^')과 그 뒤에 오는 해당 대문자로 구성됩니다. 문자가 ASCII 삭제(0x7f)이면 문자열은 '^?'입니다. 문자에 메타 비트(0x80)가 설정되어 있으면, 메타 비트가 제거되고, 앞의 규칙을 적용한 후, '!'를 결과 앞에 붙입니다.

curses.ascii.controlnames

0(NUL)에서 0x1f(US)까지 32개의 ASCII 제어 문자에 대한 ASCII 니모닉과 (순서대로), 스페이스 문자를 위한 니모닉 SP를 포함하는 33요소 문자열 배열입니다.

curses.panel — A panel stack extension for curses

패널은 깊이 기능이 추가된 창이라서, 서로의 위에 쌓을 수 있으며, 각 창의 보이는 부분만 표시됩니다. 패널을 추가하고, 스택에서 위나 아래로 옮기고, 제거할 수 있습니다.

함수

curses.panel 모듈은 다음 함수를 정의합니다:

curses.panel.bottom_panel()

패널 스택에서 최하단 패널을 반환합니다.

curses.panel.new_panel(win)

주어진 창 win과 연관 지어진 패널 객체를 반환합니다. 반환된 패널 객체가 명시적으로 참조되도록 유지해야 합니다. 그렇지 않으면 패널 객체는 가비지 수집되어 패널 스택에서 제거됩니다.

curses.panel.top_panel()

패널 스택의 최상단 패널을 반환합니다.

curses.panel.update_panels()

패널 스택이 변경된 후 가상 화면을 갱신합니다. 이것은 curses.doupdate()를 호출하지 않아서, 여러분이 직접 해야 합니다.

Panel 객체

위의 new_panel()에 의해 반환된 패널 객체는 쌓인 순서가 있는 창입니다. 패널과 연관된 창이 항상 있고, 창이 내용을 결정합니다. 패널 메서드는 패널 스택에서 창의 깊이를 담당합니다.

패널 객체에는 다음과 같은 메서드가 있습니다:

Panel.above()

현재 패널 위의 패널을 반환합니다.

Panel.below()

현재 패널 아래의 패널을 반환합니다.

Panel.bottom()

패널을 스택 맨 아래로 밉니다.”

Panel.hidden()

패널이 숨겨져 있으면 (보이지 않으면) True를, 그렇지 않으면 False를 반환합니다.

Panel.hide()

패널을 숨깁니다. 이것은 객체를 삭제하지 않고, 화면의 창을 보이지 않게 합니다.

Panel.move(y, x)

패널을 화면 좌표 (y, x)로 이동합니다.

Panel.replace(win)

패널과 연관된 창을 창 win으로 변경합니다.

Panel.set_userptr(obj)

패널의 사용자 포인터를 obj로 설정합니다. 이것은 임의의 데이터를 패널과 연관시키는 데 사용되며, 임의의 파이썬 객체가 될 수 있습니다.

Panel.show()

(숨겼을 수도 있는) 패널을 표시합니다.

Panel.top()

패널을 스택 맨 위로 밉니다.

Panel.userptr()

패널의 사용자 포인터를 반환합니다. 이것은 임의의 파이썬 객체일 수 있습니다.

Panel.window()

패널과 연관된 창 객체를 반환합니다.

platform — Access to underlying platform’s identifying data

소스 코드: Lib/platform.py [https://github.com/python/cpython/tree/main/Lib/platform.py]

참고

각 플랫폼은 알파벳순으로 나열되고, 리눅스는 유닉스 절에 포함됩니다.

크로스 플랫폼

platform.architecture(executable=sys.executable, bits='', linkage='')

다양한 아키텍처 정보에 대해 주어진 실행 파일(기본값은 파이썬 인터프리터 바이너리)을 조회합니다.

실행 파일에 사용된 비트 아키텍처와 링크 형식에 대한 정보가 들어있는 튜플 (bits, linkage)를 반환합니다. 두 값은 모두 문자열로 반환됩니다.

결정할 수 없는 값은 매개 변수 사전 설정에 따라 반환됩니다. bits가 ''로 주어지면, sizeof(pointer)(또는 파이썬 버전 < 1.5.2 에서는 sizeof(long))가 지원되는 포인터 크기를 나타내는 데 사용됩니다.

함수는 시스템의 file 명령을 사용하여 실제 작업을 수행합니다. 이것은 대부분(전부가 아니라면)의 유닉스 플랫폼과 일부 유닉스가 아닌 플랫폼에서 가능하며 실행 파일이 파이썬 인터프리터를 가리키는 경우에만 가능합니다. 위의 요구가 충족되지 않으면 합리적인 기본값이 사용됩니다.

참고

On macOS (and perhaps other platforms), executable files may be universal files containing multiple architectures.

To get at the “64-bitness” of the current interpreter, it is more reliable to query the sys.maxsize attribute:

is_64bits = sys.maxsize > 2**32

platform.machine()

Returns the machine type, e.g. 'AMD64'. An empty string is returned if the value cannot be determined.

platform.node()

컴퓨터의 네트워크 이름을 반환합니다 (완전히 정규화되지 않았을 수 있습니다!). 값을 판별할 수 없으면 빈 문자열이 반환됩니다.

platform.platform(aliased=False, terse=False)

하부 플랫폼을 식별하는 가능한 한 많은 유용한 정보를 포함하는 단일 문자열을 반환합니다.

출력은 기계가 구문 분석하기보다는 사람이 읽을 수 있도록 합니다. 다른 플랫폼에서는 다르게 보일 수 있는데, 이는 의도 된 것입니다.

aliased가 참이면, 함수는 일반 이름과 다른 시스템 이름을 보고하는 다양한 플랫폼에 대해 별칭을 사용합니다, 예를 들어 SunOS는 Solaris로 보고됩니다. 이를 구현하는 데 system_alias() 함수가 사용됩니다.

terse를 참으로 설정하면 함수가 플랫폼을 식별하는 데 필요한 절대적으로 최소한의 정보만 반환합니다.

버전 3.8에서 변경: macOS에서, 이 함수는 이제 darwin 버전 대신 macOS 버전을 얻기 위해 mac_ver() 를 사용합니다 (비어 있지 않은 릴리스 문자열을 반환한다면).

platform.processor()

(실제) 프로세서 이름을 반환합니다, 예를 들어 'amdk6'.

값을 판별할 수 없으면 빈 문자열이 반환됩니다. 많은 플랫폼이 이 정보를 제공하지 않거나 단순히 machine()과 같은 값을 반환함에 유의하십시오. NetBSD가 그렇습니다.

platform.python_build()

파이썬 빌드 번호와 날짜를 문자열로 나타내는 튜플 (buildno, builddate)를 반환합니다.

platform.python_compiler()

파이썬 컴파일에 사용된 컴파일러를 식별하는 문자열을 반환합니다.

platform.python_branch()

파이썬 구현 SCM 브랜치를 식별하는 문자열을 반환합니다.

platform.python_implementation()

파이썬 구현을 식별하는 문자열을 반환합니다. 가능한 반환 값은 이렇습니다: ‘CPython’, ‘IronPython’, ‘Jython’, ‘PyPy’.

platform.python_revision()

파이썬 구현 SCM 리비전을 식별하는 문자열을 반환합니다.

platform.python_version()

파이썬 버전을 문자열 'major.minor.patchlevel'로 반환합니다.

파이썬 sys.version과 달리, 반환 값은 항상 patchlevel을 포함함에 유의하십시오 (기본값은 0입니다).

platform.python_version_tuple()

파이썬 버전을 문자열의 튜플 (major, minor, patchlevel)로 반환합니다.

파이썬 sys.version과 달리, 반환 값은 항상 patchlevel을 포함함에 유의하십시오 (기본값은 '0'입니다).

platform.release()

Returns the system’s release, e.g. '2.2.0' or 'NT'. An empty string is returned if the value cannot be determined.

platform.system()

시스템/OS 이름을 반환합니다, 가령 'Linux', 'Darwin', 'Java', 'Windows'. 값을 판별할 수 없으면 빈 문자열이 반환됩니다.

On iOS and Android, this returns the user-facing OS name (i.e, 'iOS, 'iPadOS' or 'Android'). To obtain the kernel name ('Darwin' or 'Linux'), use os.uname().

platform.system_alias(system, release, version)

일부 시스템에서 사용되는 상용 마케팅 이름으로 별칭 된 (system, release, version)을 반환합니다. 혼동을 일으킬 수 있는 일부 경우에 정보의 순서를 변경하기도 합니다.

platform.version()

시스템의 릴리스 버전을 반환합니다, 예를 들어 '#3 on degas'. 값을 판별할 수 없으면 빈 문자열이 반환됩니다.

On iOS and Android, this is the user-facing OS version. To obtain the Darwin or Linux kernel version, use os.uname().

platform.uname()

꽤 이식성 있는 uname 인터페이스. system, node, release, version, machine, processor의 6개의 어트리뷰트를 포함한 namedtuple()를 반환합니다.

processor is resolved late, on demand.

Note: the first two attribute names differ from the names presented by os.uname(), where they are named sysname and nodename.

결정할 수 없는 항목은 ''로 설정됩니다.

버전 3.3에서 변경: Result changed from a tuple to a namedtuple().

버전 3.9에서 변경: processor is resolved late instead of immediately.

자바 플랫폼

platform.java_ver(release='', vendor='', vminfo=('', '', ''), osinfo=('', '', ''))

Jython의 버전 인터페이스.

튜플 (release, vendor, vminfo, osinfo)를 반환하는데, vminfo는 튜플 (vm_name, vm_release, vm_vendor)이고, osinfo는 튜플 (os_name, os_version, os_arch)입니다. 결정할 수 없는 값은 매개 변수로 지정된 기본값으로 설정됩니다 (기본값은 모두 ''입니다).

Deprecated since version 3.13, will be removed in version 3.15: It was largely untested, had a confusing API, and was only useful for Jython support.

윈도우 플랫폼

platform.win32_ver(release='', version='', csd='', ptype='')

Get additional version information from the Windows Registry and return a tuple (release, version, csd, ptype) referring to OS release, version number, CSD level (service pack) and OS type (multi/single processor). Values which cannot be determined are set to the defaults given as parameters (which all default to an empty string).

As a hint: ptype is 'Uniprocessor Free' on single processor NT machines and 'Multiprocessor Free' on multi processor machines. The 'Free' refers to the OS version being free of debugging code. It could also state 'Checked' which means the OS version uses debugging code, i.e. code that checks arguments, ranges, etc.

platform.win32_edition()

Returns a string representing the current Windows edition, or None if the value cannot be determined. Possible values include but are not limited to 'Enterprise', 'IoTUAP', 'ServerStandard', and 'nanoserver'.

Added in version 3.8.

platform.win32_is_iot()

win32_edition()에 의해 반환된 윈도우 에디션이 IoT 에디션으로 인식되면 True를 반환합니다.

Added in version 3.8.

macOS Platform

platform.mac_ver(release='', versioninfo=('', '', ''), machine='')

Get macOS version information and return it as tuple (release, versioninfo, machine) with versioninfo being a tuple (version, dev_stage, non_release_version).

결정할 수 없는 항목은 ''로 설정됩니다. 모든 튜플 항목은 문자열입니다.

iOS Platform

platform.ios_ver(system='', release='', model='', is_simulator=False)

Get iOS version information and return it as a namedtuple() with the following attributes:

system is the OS name; either 'iOS' or 'iPadOS'.

release is the iOS version number as a string (e.g., '17.2').

model is the device model identifier; this will be a string like 'iPhone13,2' for a physical device, or 'iPhone' on a simulator.

is_simulator is a boolean describing if the app is running on a simulator or a physical device.

Entries which cannot be determined are set to the defaults given as parameters.

유닉스 플랫폼

platform.libc_ver(executable=sys.executable, lib='', version='', chunksize=16384)

파일 executable(기본값은 파이썬 인터프리터입니다)이 링크된 libc 버전을 확인하려고 시도합니다. 문자열의 튜플 (lib, version)을 반환하는데, 조회가 실패하면 지정된 매개 변수를 기본값으로 사용합니다.

다른 libc 버전이 실행 파일에 심볼을 추가하는 방법에 대해 이 함수가 가진 지식은 아마도 gcc로 컴파일된 실행 파일에서만 사용 가능하다는 것에 유의하십시오.

파일은 chunksize 바이트의 청크 단위로 읽고 스캔됩니다.

Linux Platforms

platform.freedesktop_os_release()

Get operating system identification from os-release file and return it as a dict. The os-release file is a freedesktop.org standard [https://www.freedesktop.org/software/systemd/man/os-release.html] and is available in most Linux distributions. A noticeable exception is Android and Android-based distributions.

Raises OSError or subclass when neither /etc/os-release nor /usr/lib/os-release can be read.

On success, the function returns a dictionary where keys and values are strings. Values have their special characters like " and $ unquoted. The fields NAME, ID, and PRETTY_NAME are always defined according to the standard. All other fields are optional. Vendors may include additional fields.

Note that fields like NAME, VERSION, and VARIANT are strings suitable for presentation to users. Programs should use fields like ID, ID_LIKE, VERSION_ID, or VARIANT_ID to identify Linux distributions.

Example:

def get_like_distro():
    info = platform.freedesktop_os_release()
    ids = [info["ID"]]
    if "ID_LIKE" in info:
        # ids are space separated and ordered by precedence
        ids.extend(info["ID_LIKE"].split())
    return ids

Added in version 3.10.

Android Platform

platform.android_ver(release='', api_level=0, manufacturer='', model='', device='', is_emulator=False)

Get Android device information. Returns a namedtuple() with the following attributes. Values which cannot be determined are set to the defaults given as parameters.

release - Android version, as a string (e.g. "14").

api_level - API level of the running device, as an integer (e.g. 34 for Android 14). To get the API level which Python was built against, see sys.getandroidapilevel().

manufacturer - Manufacturer name [https://developer.android.com/reference/android/os/Build#MANUFACTURER].

model - Model name [https://developer.android.com/reference/android/os/Build#MODEL] – typically the marketing name or model number.

device - Device name [https://developer.android.com/reference/android/os/Build#DEVICE] – typically the model number or a codename.

is_emulator - True if the device is an emulator; False if it’s a physical device.

Google maintains a list of known model and device names [https://storage.googleapis.com/play_public/supported_devices.html].

Added in version 3.13.

Miscellaneous

platform.invalidate_caches()

Clear out the internal cache of information, such as the uname(). This is typically useful when the platform’s node() is changed by an external process and one needs to retrieve the updated value.

Added in version 3.14.

errno — Standard errno system symbols

This module makes available standard errno system symbols. The value of each symbol is the corresponding integer value. The names and descriptions are borrowed from linux/include/errno.h, which should be all-inclusive.

errno.errorcode

errno 값에서 하부 시스템의 문자열 이름으로의 매핑을 제공하는 딕셔너리입니다. 예를 들어, errno.errorcode[errno.EPERM]는 'EPERM'로 매핑됩니다.

숫자 에러 코드를 에러 메시지로 변환하려면, os.strerror()를 사용하십시오.

다음 목록에서, 현재 플랫폼에서 사용되지 않는 기호는 모듈에서 정의하지 않습니다. 정의된 기호의 구체적인 목록은 errno.errorcode.keys()로 사용 가능합니다. 사용할 수 있는 기호는 다음과 같습니다:

errno.EPERM

Operation not permitted. This error is mapped to the exception PermissionError.

errno.ENOENT

No such file or directory. This error is mapped to the exception FileNotFoundError.

errno.ESRCH

No such process. This error is mapped to the exception ProcessLookupError.

errno.EINTR

Interrupted system call. This error is mapped to the exception InterruptedError.

errno.EIO

I/O error – I/O 에러

errno.ENXIO

No such device or address – 그런 장치나 주소가 없습니다.

errno.E2BIG

Arg list too long – 인자 목록이 너무 깁니다.

errno.ENOEXEC

Exec format error – Exec 포맷 에러

errno.EBADF

Bad file number – 잘못된 파일 번호

errno.ECHILD

No child processes. This error is mapped to the exception ChildProcessError.

errno.EAGAIN

Try again. This error is mapped to the exception BlockingIOError.

errno.ENOMEM

Out of memory – 메모리 부족

errno.EACCES

Permission denied. This error is mapped to the exception PermissionError.

errno.EFAULT

Bad address – 잘못된 주소

errno.ENOTBLK

Block device required – 블록 장치가 필요합니다

errno.EBUSY

Device or resource busy – 장치나 자원이 사용 중입니다

errno.EEXIST

File exists. This error is mapped to the exception FileExistsError.

errno.EXDEV

Cross-device link – 장치 간 링크

errno.ENODEV

No such device – 그런 장치가 없습니다

errno.ENOTDIR

Not a directory. This error is mapped to the exception NotADirectoryError.

errno.EISDIR

Is a directory. This error is mapped to the exception IsADirectoryError.

errno.EINVAL

Invalid argument – 잘못된 인자

errno.ENFILE

File table overflow – 파일 테이블 오버플로

errno.EMFILE

Too many open files – 열려있는 파일이 너무 많습니다

errno.ENOTTY

Not a typewriter – 타자기가 아닙니다

errno.ETXTBSY

Text file busy – 텍스트 파일이 사용 중입니다

errno.EFBIG

File too large – 파일이 너무 큽니다

errno.ENOSPC

No space left on device – 장치에 남은 공간이 없습니다.

errno.ESPIPE

Illegal seek – 잘못된 탐색

errno.EROFS

Read-only file system – 읽기 전용 파일 시스템

errno.EMLINK

Too many links – 링크가 너무 많습니다

errno.EPIPE

Broken pipe. This error is mapped to the exception BrokenPipeError.

errno.EDOM

Math argument out of domain of func – 함수의 범위를 벗어난 수학 인자

errno.ERANGE

Math result not representable – 수학 결과를 표현할 수 없습니다

errno.EDEADLK

Resource deadlock would occur – 자원 교착 상태가 발생합니다

errno.ENAMETOOLONG

File name too long – 파일 이름이 너무 깁니다

errno.ENOLCK

No record locks available – 사용 가능한 레코드 록이 없습니다

errno.ENOSYS

Function not implemented – 기능이 구현되지 않았습니다

errno.ENOTEMPTY

Directory not empty – 디렉터리가 비어 있지 않습니다

errno.ELOOP

Too many symbolic links encountered – 마주친 심볼릭 링크가 너무 많습니다

errno.EWOULDBLOCK

Operation would block. This error is mapped to the exception BlockingIOError.

errno.ENOMSG

No message of desired type – 원하는 유형의 메시지가 없습니다

errno.EIDRM

Identifier removed – 식별자가 삭제되었습니다

errno.ECHRNG

Channel number out of range – 채널 번호가 범위를 벗어났습니다

errno.EL2NSYNC

Level 2 not synchronized – 수준 2가 동기화되지 않았습니다

errno.EL3HLT

Level 3 halted – 수준 3이 정지되었습니다

errno.EL3RST

Level 3 reset – 수준 3이 재설정되었습니다

errno.ELNRNG

Link number out of range – 링크 번호가 범위를 벗어났습니다

errno.EUNATCH

Protocol driver not attached – 프로토콜 드라이버가 연결되지 않았습니다

errno.ENOCSI

No CSI structure available – 사용 가능한 CSI 구조가 없습니다

errno.EL2HLT

Level 2 halted – 수준 2가 중지되었습니다

errno.EBADE

Invalid exchange – 잘못된 교환

errno.EBADR

Invalid request descriptor – 잘못된 요청 기술자

errno.EXFULL

Exchange full – 교환 포화

errno.ENOANO

No anode – anode가 없습니다

errno.EBADRQC

Invalid request code – 유효하지 않은 요청 코드

errno.EBADSLT

Invalid slot – 유효하지 않은 슬롯

errno.EDEADLOCK

File locking deadlock error – 파일 잠금 교착 상태 에러

errno.EBFONT

Bad font file format – 잘못된 글꼴 파일 형식

errno.ENOSTR

Device not a stream – 장치가 스트림이 아닙니다

errno.ENODATA

No data available – 데이터가 없습니다

errno.ETIME

Timer expired – 타이머가 만료되었습니다

errno.ENOSR

Out of streams resources – 스트림 자원 부족

errno.ENONET

Machine is not on the network – 기계가 네트워크에 없습니다.

errno.ENOPKG

Package not installed – 패키지가 설치되지 않았습니다

errno.EREMOTE

Object is remote – 객체가 원격입니다

errno.ENOLINK

Link has been severed – 링크가 절단되었습니다

errno.EADV

Advertise error – 광고 에러

errno.ESRMNT

Srmount error – srmount 에러

errno.ECOMM

Communication error on send – 전송 시 통신 에러

errno.EPROTO

Protocol error – 프로토콜 에러

errno.EMULTIHOP

Multihop attempted – 다중 홉을 시도했습니다

errno.EDOTDOT

RFS specific error – RFS 특정 에러

errno.EBADMSG

Not a data message – 데이터 메시지가 아닙니다

errno.EOVERFLOW

Value too large for defined data type – 정의된 데이터형에 비해 값이 너무 큽니다

errno.ENOTUNIQ

Name not unique on network – 이름이 네트워크에서 고유하지 않습니다

errno.EBADFD

File descriptor in bad state – 잘못된 상태의 파일 기술자

errno.EREMCHG

Remote address changed – 원격 주소가 변경되었습니다

errno.ELIBACC

Can not access a needed shared library – 필요한 공유 라이브러리에 액세스할 수 없습니다.

errno.ELIBBAD

Accessing a corrupted shared library – 손상된 공유 라이브러리 액세스

errno.ELIBSCN

.lib section in a.out corrupted – 손상된 a.out의 .lib 섹션

errno.ELIBMAX

Attempting to link in too many shared libraries – 너무 많은 공유 라이브러리 연결 시도

errno.ELIBEXEC

Cannot exec a shared library directly – 공유 라이브러리를 직접 실행할 수 없습니다

errno.EILSEQ

Illegal byte sequence – 잘못된 바이트 시퀀스

errno.ERESTART

Interrupted system call should be restarted – 중단된 시스템 호출을 다시 시작해야 합니다

errno.ESTRPIPE

Streams pipe error – 스트림 파이프 에러

errno.EUSERS

Too many users – 사용자가 너무 많습니다

errno.ENOTSOCK

Socket operation on non-socket – 비 소켓에 대한 소켓 연산

errno.EDESTADDRREQ

Destination address required – 목적지 주소가 필요합니다

errno.EMSGSIZE

Message too long – 메시지가 너무 깁니다

errno.EPROTOTYPE

Protocol wrong type for socket – 소켓에 대한 프로토콜 유형이 잘못되었습니다

errno.ENOPROTOOPT

Protocol not available – 프로토콜을 사용할 수 없습니다

errno.EPROTONOSUPPORT

Protocol not supported – 지원되지 않는 프로토콜

errno.ESOCKTNOSUPPORT

Socket type not supported – 지원되지 않는 소켓 유형

errno.EOPNOTSUPP

Operation not supported on transport endpoint – 트랜스포트 끝점에서 지원되지 않는 연산

errno.ENOTSUP

Operation not supported

Added in version 3.2.

errno.EPFNOSUPPORT

Protocol family not supported – 지원되지 않는 프로토콜 패밀리

errno.EAFNOSUPPORT

Address family not supported by protocol – 프로토콜이 지원하지 않는 주소 패밀리

errno.EADDRINUSE

Address already in use – 이미 사용 중인 주소

errno.EADDRNOTAVAIL

Cannot assign requested address – 요청된 주소를 할당할 수 없습니다.

errno.ENETDOWN

Network is down – 네트워크가 다운되었습니다

errno.ENETUNREACH

Network is unreachable – 네트워크에 도달할 수 없습니다

errno.ENETRESET

Network dropped connection because of reset – 재설정으로 인해 네트워크 연결이 끊겼습니다

errno.ECONNABORTED

Software caused connection abort. This error is mapped to the exception ConnectionAbortedError.

errno.ECONNRESET

Connection reset by peer. This error is mapped to the exception ConnectionResetError.

errno.ENOBUFS

No buffer space available – 사용 가능한 버퍼 공간이 없습니다.

errno.EISCONN

Transport endpoint is already connected – 트랜스포트 끝점이 이미 연결되어 있습니다.

errno.ENOTCONN

Transport endpoint is not connected – 트랜스포트 끝점이 연결되어 있지 않습니다.

errno.ESHUTDOWN

Cannot send after transport endpoint shutdown. This error is mapped to the exception BrokenPipeError.

errno.ETOOMANYREFS

Too many references: cannot splice – 참조가 너무 많습니다: 연결할 수 없습니다

errno.ETIMEDOUT

Connection timed out. This error is mapped to the exception TimeoutError.

errno.ECONNREFUSED

Connection refused. This error is mapped to the exception ConnectionRefusedError.

errno.EHOSTDOWN

Host is down – 호스트가 다운되었습니다

errno.EHOSTUNREACH

No route to host – 호스트로 가는 길이 없습니다

errno.EALREADY

Operation already in progress. This error is mapped to the exception BlockingIOError.

errno.EINPROGRESS

Operation now in progress. This error is mapped to the exception BlockingIOError.

errno.ESTALE

Stale NFS file handle – 오래된 NFS 파일 핸들

errno.EUCLEAN

Structure needs cleaning – 구조 청소 필요

errno.ENOTNAM

Not a XENIX named type file – XENIX 이름 붙은 형식 파일이 아닙니다

errno.ENAVAIL

No XENIX semaphores available – 사용할 수 있는 XENIX 세마포어가 없습니다

errno.EISNAM

Is a named type file – 이름 붙은 형식 파일입니다

errno.EREMOTEIO

Remote I/O error – 원격 I/O 에러

errno.EDQUOT

Quota exceeded – 할당량 초과

errno.EQFULL

Interface output queue is full

Added in version 3.11.

errno.ENOTCAPABLE

Capabilities insufficient. This error is mapped to the exception PermissionError.

Availability: WASI, FreeBSD

Added in version 3.11.1.

errno.ECANCELED

Operation canceled

Added in version 3.2.

errno.EOWNERDEAD

Owner died

Added in version 3.2.

errno.ENOTRECOVERABLE

State not recoverable

Added in version 3.2.

ctypes — A foreign function library for Python

Source code: Lib/ctypes [https://github.com/python/cpython/tree/main/Lib/ctypes]

ctypes는 파이썬용 외부 함수(foreign function) 라이브러리입니다. C 호환 데이터형을 제공하며, DLL 또는 공유 라이브러리에 있는 함수를 호출할 수 있습니다. 이 라이브러리들을 순수 파이썬으로 감싸는 데 사용할 수 있습니다.

ctypes 자습서

Note: The code samples in this tutorial use doctest to make sure that they actually work. Since some code samples behave differently under Linux, Windows, or macOS, they contain doctest directives in comments.

참고: 일부 코드 예제는 ctypes c_int 형을 참조합니다. sizeof(long) == sizeof(int)인 플랫폼에서, 이는 c_long의 별칭입니다. 따라서 c_int를 기대할 때 c_long가 인쇄되더라도 혼란스러워하지 않아도 됩니다 — 이것들은 실제로 같은 형입니다.

동적 링크 라이브러리 로드하기

ctypes는 동적 링크 라이브러리 로드를 위해 cdll을, 그리고 윈도우에서는 windll 및 oledll 객체를, 노출합니다.

You load libraries by accessing them as attributes of these objects. cdll loads libraries which export functions using the standard cdecl calling convention, while windll libraries call functions using the stdcall calling convention. oledll also uses the stdcall calling convention, and assumes the functions return a Windows HRESULT error code. The error code is used to automatically raise an OSError exception when the function call fails.

버전 3.3에서 변경: 윈도우 에러는 WindowsError를 일으켜왔습니다. 이제는 OSError의 별칭입니다.

Here are some examples for Windows. Note that msvcrt is the MS standard C library containing most standard C functions, and uses the cdecl calling convention:

>>> from ctypes import *
>>> print(windll.kernel32)
<WinDLL 'kernel32', handle ... at ...>
>>> print(cdll.msvcrt)
<CDLL 'msvcrt', handle ... at ...>
>>> libc = cdll.msvcrt
>>>

윈도우는 일반적인 .dll 파일 접미사를 자동으로 추가합니다.

참고

cdll.msvcrt를 통해 표준 C 라이브러리에 액세스하면 파이썬에서 사용되는 라이브러리와 호환되지 않는 오래된 라이브러리 버전이 사용됩니다. 가능하면 파이썬 자체의 기능을 사용하거나, msvcrt 모듈을 임포트 해서 사용하십시오.

On Linux, it is required to specify the filename including the extension to load a library, so attribute access can not be used to load libraries. Either the LoadLibrary() method of the dll loaders should be used, or you should load the library by creating an instance of CDLL by calling the constructor:

>>> cdll.LoadLibrary("libc.so.6")
<CDLL 'libc.so.6', handle ... at ...>
>>> libc = CDLL("libc.so.6")
>>> libc
<CDLL 'libc.so.6', handle ... at ...>
>>>

로드된 dll에서 함수에 액세스하기

함수는 dll 객체의 어트리뷰트로 액세스 됩니다:

>>> libc.printf
<_FuncPtr object at 0x...>
>>> print(windll.kernel32.GetModuleHandleA)
<_FuncPtr object at 0x...>
>>> print(windll.kernel32.MyOwnFunction)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "ctypes.py", line 239, in __getattr__
    func = _StdcallFuncPtr(name, self)
AttributeError: function 'MyOwnFunction' not found
>>>

Note that win32 system dlls like kernel32 and user32 often export ANSI as well as UNICODE versions of a function. The UNICODE version is exported with a W appended to the name, while the ANSI version is exported with an A appended to the name. The win32 GetModuleHandle function, which returns a module handle for a given module name, has the following C prototype, and a macro is used to expose one of them as GetModuleHandle depending on whether UNICODE is defined or not:

/* ANSI version */
HMODULE GetModuleHandleA(LPCSTR lpModuleName);
/* UNICODE version */
HMODULE GetModuleHandleW(LPCWSTR lpModuleName);

windll는 마술적으로 이 중 하나를 선택하려고 하지 않으므로, GetModuleHandleA 나 GetModuleHandleW를 명시적으로 지정하여 필요한 버전에 액세스해야 하고, 그런 다음 각각 바이트열이나 문자열 객체로 호출해야 합니다.

때때로, dll은 "??2@YAPAXI@Z"와 같은 유효한 파이썬 식별자가 아닌 이름으로 함수를 내보냅니다. 이때는 getattr()를 사용하여 함수를 조회해야 합니다:

>>> getattr(cdll.msvcrt, "??2@YAPAXI@Z")
<_FuncPtr object at 0x...>
>>>

윈도우에서, 일부 dll은 이름이 아니라 서수(ordinal)로 함수를 내보냅니다. 이 함수는 서수로 dll 객체를 인덱싱하여 액세스할 수 있습니다:

>>> cdll.kernel32[1]
<_FuncPtr object at 0x...>
>>> cdll.kernel32[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "ctypes.py", line 310, in __getitem__
    func = _StdcallFuncPtr(name, self)
AttributeError: function ordinal 0 not found
>>>

함수 호출하기

You can call these functions like any other Python callable. This example uses the rand() function, which takes no arguments and returns a pseudo-random integer:

>>> print(libc.rand())
1804289383

On Windows, you can call the GetModuleHandleA() function, which returns a win32 module handle (passing None as single argument to call it with a NULL pointer):

>>> print(hex(windll.kernel32.GetModuleHandleA(None)))
0x1d000000
>>>

cdecl 호출 규칙을 사용하여 stdcall 함수를 호출하면 ValueError가 발생하고, 그 반대도 마찬가지입니다:

>>> cdll.kernel32.GetModuleHandleA(None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: Procedure probably called with not enough arguments (4 bytes missing)
>>>

>>> windll.msvcrt.printf(b"spam")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: Procedure probably called with too many arguments (4 bytes in excess)
>>>

올바른 호출 규칙을 찾으려면 C 헤더 파일이나 호출할 함수에 대한 설명서를 살펴봐야 합니다.

윈도우에서, ctypes는 함수가 유효하지 않은 인자 값을 사용하여 호출될 때, 일반적인 보호 오류로 인한 충돌을 방지하기 위해 win32 구조적 예외 처리를 사용합니다:

>>> windll.kernel32.GetModuleHandleA(32)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: exception: access violation reading 0x00000020
>>>

그러나, ctypes로 파이썬을 충돌시킬 방법이 많으므로, 어쨌든 주의해야 합니다. faulthandler 모듈은 충돌을 디버깅하는 데 도움이 될 수 있습니다 (예를 들어, 오류가 있는 C 라이브러리 호출로 인한 세그먼트 오류).

None, integers, bytes objects and (unicode) strings are the only native Python objects that can directly be used as parameters in these function calls. None is passed as a C NULL pointer, bytes objects and strings are passed as pointer to the memory block that contains their data (char* or wchar_t*). Python integers are passed as the platform’s default C int type, their value is masked to fit into the C type.

다른 매개 변수 형으로 함수를 호출하기 전에, ctypes 데이터형에 대해 더 알아야 합니다.

기본 데이터형

ctypes는 많은 기본적인 C 호환 데이터형을 정의합니다.:

ctypes 형

C 형

파이썬 형

c_bool

_Bool

bool (1)

c_char

char

1-문자 바이트열 객체

c_wchar

wchar_t

1-문자 문자열

c_byte

char

int

c_ubyte

unsigned char

int

c_short

short

int

c_ushort

unsigned short

int

c_int

int

int

c_uint

unsigned int

int

c_long

long

int

c_ulong

unsigned long

int

c_longlong

__int64 or long long

int

c_ulonglong

unsigned __int64 or unsigned long long

int

c_size_t

size_t

int

c_ssize_t

ssize_t or Py_ssize_t

int

c_time_t

time_t

int

c_float

float

float

c_double

double

float

c_longdouble

long double

float

c_char_p

char* (NUL terminated)

바이트열 객체나 None

c_wchar_p

wchar_t* (NUL terminated)

문자열이나 None

c_void_p

void*

int 나 None

생성자는 논릿값을 가진 모든 객체를 받아들입니다.

Additionally, if IEC 60559 compatible complex arithmetic (Annex G) is supported, the following complex types are available:

ctypes 형

C 형

파이썬 형

c_float_complex

float complex

complex

c_double_complex

double complex

complex

c_longdouble_complex

long double complex

complex

이 모든 형은 올바른 형과 값의 선택적 초기화자로 호출해서 만들어질 수 있습니다:

>>> c_int()
c_long(0)
>>> c_wchar_p("Hello, World")
c_wchar_p(140018365411392)
>>> c_ushort(-3)
c_ushort(65533)
>>>

이러한 형은 가변이므로, 값을 나중에 변경할 수도 있습니다:

>>> i = c_int(42)
>>> print(i)
c_long(42)
>>> print(i.value)
42
>>> i.value = -99
>>> print(i.value)
-99
>>>

c_char_p, c_wchar_p 및 c_void_p 포인터형의 인스턴스에 새 값을 대입하면 포인터가 가리키는 메모리 위치가 변경됩니다, 메모리 블록의 내용이 아닙니다 (당연히 아닙니다, 파이썬 바이트열 객체는 불변입니다):

>>> s = "Hello, World"
>>> c_s = c_wchar_p(s)
>>> print(c_s)
c_wchar_p(139966785747344)
>>> print(c_s.value)
Hello World
>>> c_s.value = "Hi, there"
>>> print(c_s)              # the memory location has changed
c_wchar_p(139966783348904)
>>> print(c_s.value)
Hi, there
>>> print(s)                # first object is unchanged
Hello, World
>>>

그러나, 이것들을 가변 메모리에 대한 포인터를 예상하는 함수에 전달하지 않도록 주의해야 합니다. 가변 메모리 블록이 필요하다면, ctypes에는 다양한 방법으로 이를 만드는 create_string_buffer() 함수가 있습니다. 현재 메모리 블록 내용은 raw 프로퍼티를 사용하여 액세스(또는 변경)할 수 있습니다; NUL 종료 문자열로 액세스하려면 value 프로퍼티를 사용하십시오:

>>> from ctypes import *
>>> p = create_string_buffer(3)            # create a 3 byte buffer, initialized to NUL bytes
>>> print(sizeof(p), repr(p.raw))
3 b'\x00\x00\x00'
>>> p = create_string_buffer(b"Hello")     # create a buffer containing a NUL terminated string
>>> print(sizeof(p), repr(p.raw))
6 b'Hello\x00'
>>> print(repr(p.value))
b'Hello'
>>> p = create_string_buffer(b"Hello", 10) # create a 10 byte buffer
>>> print(sizeof(p), repr(p.raw))
10 b'Hello\x00\x00\x00\x00\x00'
>>> p.value = b"Hi"
>>> print(sizeof(p), repr(p.raw))
10 b'Hi\x00lo\x00\x00\x00\x00\x00'
>>>

The create_string_buffer() function replaces the old c_buffer() function (which is still available as an alias). To create a mutable memory block containing unicode characters of the C type wchar_t, use the create_unicode_buffer() function.

함수 호출하기, 계속

printf는 sys.stdout이 아니라 실제 표준 출력으로 인쇄하므로, 이 예제는 콘솔 프롬프트에서만 작동하고 IDLE 이나 PythonWin에서는 작동하지 않음에 유의하십시오:

>>> printf = libc.printf
>>> printf(b"Hello, %s\n", b"World!")
Hello, World!
14
>>> printf(b"Hello, %S\n", "World!")
Hello, World!
14
>>> printf(b"%d bottles of beer\n", 42)
42 bottles of beer
19
>>> printf(b"%f bottles of beer\n", 42.5)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ctypes.ArgumentError: argument 2: TypeError: Don't know how to convert parameter 2
>>>

이전에 언급했듯이, 정수, 문자열 및 바이트열 객체를 제외한 모든 파이썬 형은 필요한 C 데이터형으로 변환될 수 있도록 해당하는 ctypes 형으로 래핑 되어야 합니다:

>>> printf(b"An int %d, a double %f\n", 1234, c_double(3.14))
An int 1234, a double 3.140000
31
>>>

Calling variadic functions

On a lot of platforms calling variadic functions through ctypes is exactly the same as calling functions with a fixed number of parameters. On some platforms, and in particular ARM64 for Apple Platforms, the calling convention for variadic functions is different than that for regular functions.

On those platforms it is required to specify the argtypes attribute for the regular, non-variadic, function arguments:

libc.printf.argtypes = [ctypes.c_char_p]

Because specifying the attribute does not inhibit portability it is advised to always specify argtypes for all variadic functions.

사용자 정의 데이터형을 사용하여 함수 호출하기

You can also customize ctypes argument conversion to allow instances of your own classes be used as function arguments. ctypes looks for an _as_parameter_ attribute and uses this as the function argument. The attribute must be an integer, string, bytes, a ctypes instance, or an object with an _as_parameter_ attribute:

>>> class Bottles:
...     def __init__(self, number):
...         self._as_parameter_ = number
...
>>> bottles = Bottles(42)
>>> printf(b"%d bottles of beer\n", bottles)
42 bottles of beer
19
>>>

If you don’t want to store the instance’s data in the _as_parameter_ instance variable, you could define a property which makes the attribute available on request.

필수 인자 형 (함수 프로토타입) 지정하기

It is possible to specify the required argument types of functions exported from DLLs by setting the argtypes attribute.

argtypes must be a sequence of C data types (the printf() function is probably not a good example here, because it takes a variable number and different types of parameters depending on the format string, on the other hand this is quite handy to experiment with this feature):

>>> printf.argtypes = [c_char_p, c_char_p, c_int, c_double]
>>> printf(b"String '%s', Int %d, Double %f\n", b"Hi", 10, 2.2)
String 'Hi', Int 10, Double 2.200000
37
>>>

포맷을 지정하면 호환되지 않는 인자 형으로부터 보호하고(C 함수의 프로토타입처럼), 유효한 형으로 인자를 변환하려고 시도합니다:

>>> printf(b"%d %d %d", 1, 2, 3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ctypes.ArgumentError: argument 2: TypeError: 'int' object cannot be interpreted as ctypes.c_char_p
>>> printf(b"%s %d %f\n", b"X", 2, 3)
X 2 3.000000
13
>>>

If you have defined your own classes which you pass to function calls, you have to implement a from_param() class method for them to be able to use them in the argtypes sequence. The from_param() class method receives the Python object passed to the function call, it should do a typecheck or whatever is needed to make sure this object is acceptable, and then return the object itself, its _as_parameter_ attribute, or whatever you want to pass as the C function argument in this case. Again, the result should be an integer, string, bytes, a ctypes instance, or an object with an _as_parameter_ attribute.

반환형

By default functions are assumed to return the C int type. Other return types can be specified by setting the restype attribute of the function object.

The C prototype of time() is time_t time(time_t *). Because time_t might be of a different type than the default return type int, you should specify the restype attribute:

>>> libc.time.restype = c_time_t

The argument types can be specified using argtypes:

>>> libc.time.argtypes = (POINTER(c_time_t),)

To call the function with a NULL pointer as first argument, use None:

>>> print(libc.time(None))
1150640792

Here is a more advanced example, it uses the strchr() function, which expects a string pointer and a char, and returns a pointer to a string:

>>> strchr = libc.strchr
>>> strchr(b"abcdef", ord("d"))
8059983
>>> strchr.restype = c_char_p    # c_char_p is a pointer to a string
>>> strchr(b"abcdef", ord("d"))
b'def'
>>> print(strchr(b"abcdef", ord("x")))
None
>>>

If you want to avoid the ord("x") calls above, you can set the argtypes attribute, and the second argument will be converted from a single character Python bytes object into a C char:

>>> strchr.restype = c_char_p
>>> strchr.argtypes = [c_char_p, c_char]
>>> strchr(b"abcdef", b"d")
b'def'
>>> strchr(b"abcdef", b"def")
Traceback (most recent call last):
ctypes.ArgumentError: argument 2: TypeError: one character bytes, bytearray or integer expected
>>> print(strchr(b"abcdef", b"x"))
None
>>> strchr(b"abcdef", b"d")
b'def'
>>>

You can also use a callable Python object (a function or a class for example) as the restype attribute, if the foreign function returns an integer. The callable will be called with the integer the C function returns, and the result of this call will be used as the result of your function call. This is useful to check for error return values and automatically raise an exception:

>>> GetModuleHandle = windll.kernel32.GetModuleHandleA
>>> def ValidHandle(value):
...     if value == 0:
...         raise WinError()
...     return value
...
>>>
>>> GetModuleHandle.restype = ValidHandle
>>> GetModuleHandle(None)
486539264
>>> GetModuleHandle("something silly")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in ValidHandle
OSError: [Errno 126] The specified module could not be found.
>>>

WinError는 윈도우 FormatMessage() api를 호출하여 에러 코드의 문자열 표현을 가져오고, 예외를 반환하는 함수입니다. WinError는 선택적 에러 코드 매개 변수를 취합니다, 제공하지 않으면 GetLastError()를 호출하여 에러 코드를 가져옵니다.

Please note that a much more powerful error checking mechanism is available through the errcheck attribute; see the reference manual for details.

포인터 전달하기 (또는: 참조로 매개 변수 전달하기)

때때로 C api 함수는 매개 변수로 데이터형을 가리키는 포인터를 기대합니다, 아마도 해당 위치에 쓰기 위해서, 또는 데이터가 너무 커서 값으로 전달할 수 없어서. 이것은 참조로 매개 변수 전달하기로 알려져 있기도 합니다.

ctypes는 매개 변수를 참조로 전달하는 데 사용되는 byref() 함수를 내보냅니다. 같은 효과를 pointer() 함수로도 얻을 수 있습니다. 하지만 pointer()는 실제 포인터 객체를 생성하기 때문에 더 많은 작업을 수행하므로, 파이썬 자체에서 포인터 객체가 필요하지 않으면 byref()를 사용하는 것이 더 빠릅니다.:

>>> i = c_int()
>>> f = c_float()
>>> s = create_string_buffer(b'\000' * 32)
>>> print(i.value, f.value, repr(s.value))
0 0.0 b''
>>> libc.sscanf(b"1 3.14 Hello", b"%d %f %s",
...             byref(i), byref(f), s)
3
>>> print(i.value, f.value, repr(s.value))
1 3.1400001049 b'Hello'
>>>

구조체와 공용체

Structures and unions must derive from the Structure and Union base classes which are defined in the ctypes module. Each subclass must define a _fields_ attribute. _fields_ must be a list of 2-tuples, containing a field name and a field type.

필드형은 c_int와 같은 ctypes 형이거나 다른 파생된 ctypes 형(구조체, 공용체, 배열, 포인터)이어야 합니다.

다음은 x 및 y라는 두 개의 정수가 포함된 POINT 구조체의 간단한 예제이며, 생성자에서 구조체를 초기화하는 방법도 보여줍니다:

>>> from ctypes import *
>>> class POINT(Structure):
...     _fields_ = [("x", c_int),
...                 ("y", c_int)]
...
>>> point = POINT(10, 20)
>>> print(point.x, point.y)
10 20
>>> point = POINT(y=5)
>>> print(point.x, point.y)
0 5
>>> POINT(1, 2, 3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: too many initializers
>>>

그러나, 훨씬 복잡한 구조를 만들 수 있습니다. 구조체는 필드형으로 구조체를 사용하여 다른 구조체를 포함할 수 있습니다.

다음은 upperleft 및 lowerright라는 두 개의 POINT를 포함하는 RECT 구조체입니다:

>>> class RECT(Structure):
...     _fields_ = [("upperleft", POINT),
...                 ("lowerright", POINT)]
...
>>> rc = RECT(point)
>>> print(rc.upperleft.x, rc.upperleft.y)
0 5
>>> print(rc.lowerright.x, rc.lowerright.y)
0 0
>>>

중첩된 구조체는 여러 가지 방법으로 생성자에서 초기화할 수 있습니다:

>>> r = RECT(POINT(1, 2), POINT(3, 4))
>>> r = RECT((1, 2), (3, 4))

필드 디스크립터는 클래스에서 조회할 수 있습니다. 유용한 정보를 제공할 수 있으므로 디버깅에 유용합니다:

>>> print(POINT.x)
<Field type=c_long, ofs=0, size=4>
>>> print(POINT.y)
<Field type=c_long, ofs=4, size=4>
>>>

경고

ctypes는 비트 필드가 있는 공용체나 구조체를 값으로 함수에 전달할 수 없습니다. 32비트 x86에서 작동할 수 있지만, 일반적으로 작동은 라이브러리가 보증하지 않습니다. 비트 필드가 있는 공용체와 구조체는 항상 포인터로 함수에 전달되어야 합니다.

Structure/union layout, alignment and byte order

By default, Structure and Union fields are laid out in the same way the C compiler does it. It is possible to override this behavior entirely by specifying a _layout_ class attribute in the subclass definition; see the attribute documentation for details.

It is possible to specify the maximum alignment for the fields by setting the _pack_ class attribute to a positive integer. This matches what #pragma pack(n) does in MSVC.

It is also possible to set a minimum alignment for how the subclass itself is packed in the same way #pragma align(n) works in MSVC. This can be achieved by specifying a :_align_ class attribute in the subclass definition.

ctypes는 구조체와 공용체에 기본(native) 바이트 순서를 사용합니다. 기본이 아닌 바이트 순서로 구조체를 만들려면 BigEndianStructure, LittleEndianStructure, BigEndianUnion 및 LittleEndianUnion 베이스 클래스 중 하나를 사용할 수 있습니다. 이러한 클래스들은 포인터 필드를 포함할 수 없습니다.

구조체와 공용체의 비트 필드

It is possible to create structures and unions containing bit fields. Bit fields are only possible for integer fields, the bit width is specified as the third item in the _fields_ tuples:

>>> class Int(Structure):
...     _fields_ = [("first_16", c_int, 16),
...                 ("second_16", c_int, 16)]
...
>>> print(Int.first_16)
<Field type=c_long, ofs=0:0, bits=16>
>>> print(Int.second_16)
<Field type=c_long, ofs=0:16, bits=16>
>>>

배열

배열은 같은 형의 고정 된 수의 인스턴스를 포함하는 시퀀스입니다.

배열형을 만드는 데 권장되는 방법은 데이터형에 양의 정수를 곱하는 것입니다:

TenPointsArrayType = POINT * 10

다음은 다소 인공적인 데이터형의 예입니다. 다른 항목들과 함께 4개의 POINT를 포함하는 구조체입니다:

>>> from ctypes import *
>>> class POINT(Structure):
...     _fields_ = ("x", c_int), ("y", c_int)
...
>>> class MyStruct(Structure):
...     _fields_ = [("a", c_int),
...                 ("b", c_float),
...                 ("point_array", POINT * 4)]
>>>
>>> print(len(MyStruct().point_array))
4
>>>

인스턴스는 클래스를 호출하는 일반적인 방법으로 만들어집니다:

arr = TenPointsArrayType()
for pt in arr:
    print(pt.x, pt.y)

위 코드는 배열 내용이 0으로 초기화되기 때문에, 일련의 0 0 줄을 인쇄합니다.

올바른 형의 초기화자를 지정할 수도 있습니다:

>>> from ctypes import *
>>> TenIntegers = c_int * 10
>>> ii = TenIntegers(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
>>> print(ii)
<c_long_Array_10 object at 0x...>
>>> for i in ii: print(i, end=" ")
...
1 2 3 4 5 6 7 8 9 10
>>>

포인터

포인터 인스턴스는 ctypes 형에 pointer() 함수를 호출해서 만듭니다:

>>> from ctypes import *
>>> i = c_int(42)
>>> pi = pointer(i)
>>>

포인터 인스턴스는 포인터가 가리키는 객체(위에서는 i 객체)를 반환하는 contents 어트리뷰트를 가집니다:

>>> pi.contents
c_long(42)
>>>

ctypes에는 OOR(원래 객체 반환, original object return)이 없다는 것에 유의하십시오. 어트리뷰트를 가져올 때마다 (동등하지만) 새로운 객체를 만듭니다:

>>> pi.contents is i
False
>>> pi.contents is pi.contents
False
>>>

다른 c_int 인스턴스를 포인터의 contents 어트리뷰트에 대입하면 포인터는 이 인스턴스가 저장되어있는 메모리 위치를 가리키게 됩니다:

>>> i = c_int(99)
>>> pi.contents = i
>>> pi.contents
c_long(99)
>>>

포인터 인스턴스는 정수로도 인덱싱할 수 있습니다.:

>>> pi[0]
99
>>>

정수 인덱스에 대입하면 가리키고 있는 값이 바뀝니다:

>>> print(i)
c_long(99)
>>> pi[0] = 22
>>> print(i)
c_long(22)
>>>

0이 아닌 인덱스를 사용할 수도 있지만, C에서와 마찬가지로 자신이 하는 일을 알아야 합니다: 임의의 메모리 위치를 액세스하거나 변경할 수 있습니다. 일반적으로 C 함수에서 포인터를 받고, 포인터가 실제로 단일 항목 대신 배열을 가리키는 것을 알 때만 이 기능을 사용합니다.

장막 뒤에서, pointer() 함수는 단순히 포인터 인스턴스를 만드는 것 이상을 수행합니다. 먼저 포인터 형을 만들어야 합니다. 이것은 임의의 ctypes 형을 받아들이고, 새로운 형을 반환하는 POINTER() 함수로 수행됩니다:

>>> PI = POINTER(c_int)
>>> PI
<class 'ctypes.LP_c_long'>
>>> PI(42)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: expected c_long instead of int
>>> PI(c_int(42))
<ctypes.LP_c_long object at 0x...>
>>>

인자 없이 포인터형을 호출하면 NULL 포인터가 만들어집니다. NULL 포인터는 False 논릿값을 갖습니다:

>>> null_ptr = POINTER(c_int)()
>>> print(bool(null_ptr))
False
>>>

ctypes는 포인터를 역참조(dereference)할 때 NULL인지 확인합니다 (하지만 NULL이 아닌 잘못된 포인터를 역참조하면 파이썬을 충돌시킵니다):

>>> null_ptr[0]
Traceback (most recent call last):
    ....
ValueError: NULL pointer access
>>>

>>> null_ptr[0] = 1234
Traceback (most recent call last):
    ....
ValueError: NULL pointer access
>>>

형 변환

Usually, ctypes does strict type checking. This means, if you have POINTER(c_int) in the argtypes list of a function or as the type of a member field in a structure definition, only instances of exactly the same type are accepted. There are some exceptions to this rule, where ctypes accepts other objects. For example, you can pass compatible array instances instead of pointer types. So, for POINTER(c_int), ctypes accepts an array of c_int:

>>> class Bar(Structure):
...     _fields_ = [("count", c_int), ("values", POINTER(c_int))]
...
>>> bar = Bar()
>>> bar.values = (c_int * 3)(1, 2, 3)
>>> bar.count = 3
>>> for i in range(bar.count):
...     print(bar.values[i])
...
1
2
3
>>>

In addition, if a function argument is explicitly declared to be a pointer type (such as POINTER(c_int)) in argtypes, an object of the pointed type (c_int in this case) can be passed to the function. ctypes will apply the required byref() conversion in this case automatically.

POINTER 형 필드를 NULL로 설정하려면, None을 대입할 수 있습니다:

>>> bar.values = None
>>>

때에 따라 호환되지 않는 형의 인스턴스가 있을 수 있습니다. C에서는, 한 형을 다른 형으로 강제 변환(cast)할 수 있습니다. ctypes는 같은 방식으로 사용할 수 있는 cast() 함수를 제공합니다. 위에 정의된 Bar 구조체는 values 필드에 대해 POINTER(c_int) 포인터나 c_int 배열을 받아들이지만 다른 형의 인스턴스는 허용하지 않습니다:

>>> bar.values = (c_byte * 4)()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: incompatible types, c_byte_Array_4 instance instead of LP_c_long instance
>>>

이럴 때, cast() 함수가 편리합니다.

cast() 함수는 ctypes 인스턴스를 다른 ctypes 데이터형에 대한 포인터로 변환하는 데 사용할 수 있습니다. cast()는 두 개의 매개 변수, 어떤 종류의 포인터로 변환될 수 있는 ctypes 객체와 ctypes 포인터형을 받아들입니다. 첫 번째 인자와 같은 메모리 블록을 참조하는 두 번째 인자의 인스턴스를 반환합니다:

>>> a = (c_byte * 4)()
>>> cast(a, POINTER(c_int))
<ctypes.LP_c_long object at ...>
>>>

따라서, cast()는 Bar 구조체의 values 필드에 대입하는 데 사용할 수 있습니다:

>>> bar = Bar()
>>> bar.values = cast((c_byte * 4)(), POINTER(c_int))
>>> print(bar.values[0])
0
>>>

불완전한 형

불완전한 형은 멤버가 아직 지정되지 않은 구조체, 공용체 또는 배열입니다. C에서, 이것들은 나중에 정의되는 전방 선언(forward declaration)으로 지정됩니다:

struct cell; /* forward declaration */

struct cell {
    char *name;
    struct cell *next;
};

ctypes 코드로 그대로 옮기면 이렇게 되지만, 작동하지는 않습니다:

>>> class cell(Structure):
...     _fields_ = [("name", c_char_p),
...                 ("next", POINTER(cell))]
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in cell
NameError: name 'cell' is not defined
>>>

because the new class cell is not available in the class statement itself. In ctypes, we can define the cell class and set the _fields_ attribute later, after the class statement:

>>> from ctypes import *
>>> class cell(Structure):
...     pass
...
>>> cell._fields_ = [("name", c_char_p),
...                  ("next", POINTER(cell))]
>>>

해 봅시다. 우리는 두 개의 cell 인스턴스를 만들고, 서로를 가리키도록 한 다음, 마지막으로 포인터 체인을 몇 번 따라갑니다:

>>> c1 = cell()
>>> c1.name = b"foo"
>>> c2 = cell()
>>> c2.name = b"bar"
>>> c1.next = pointer(c2)
>>> c2.next = pointer(c1)
>>> p = c1
>>> for i in range(8):
...     print(p.name, end=" ")
...     p = p.next[0]
...
foo bar foo bar foo bar foo bar
>>>

콜백 함수

ctypes는 파이썬 콜러블로부터 C에서 호출 가능한 함수 포인터를 만들 수 있습니다. 이들은 때로 콜백 함수(callback functions)라고 불립니다.

먼저, 콜백 함수를 위한 클래스를 만들어야 합니다. 클래스는 호출 규칙, 반환형 및 이 함수가 받는 인자의 수와 형을 알고 있습니다.

CFUNCTYPE() 팩토리 함수는 cdecl 호출 규칙을 사용하여 콜백 함수의 형을 만듭니다. 윈도우에서, WINFUNCTYPE() 팩토리 함수는 stdcall 호출 규칙을 사용하여 콜백 함수 형을 만듭니다.

이러한 팩토리 함수는 모두 첫 번째 인자로 결과 형을, 나머지 인자로 콜백 함수가 기대하는 인자 형들로 호출됩니다.

I will present an example here which uses the standard C library’s qsort() function, that is used to sort items with the help of a callback function. qsort() will be used to sort an array of integers:

>>> IntArray5 = c_int * 5
>>> ia = IntArray5(5, 1, 7, 33, 99)
>>> qsort = libc.qsort
>>> qsort.restype = None
>>>

qsort() must be called with a pointer to the data to sort, the number of items in the data array, the size of one item, and a pointer to the comparison function, the callback. The callback will then be called with two pointers to items, and it must return a negative integer if the first item is smaller than the second, a zero if they are equal, and a positive integer otherwise.

따라서 콜백 함수는 정수에 대한 포인터들을 받고 정수를 반환해야 합니다. 먼저 콜백 함수를 위한 형을 만듭니다:

>>> CMPFUNC = CFUNCTYPE(c_int, POINTER(c_int), POINTER(c_int))
>>>

시작하기 위해, 전달된 값을 보여주는 간단한 콜백이 있습니다:

>>> def py_cmp_func(a, b):
...     print("py_cmp_func", a[0], b[0])
...     return 0
...
>>> cmp_func = CMPFUNC(py_cmp_func)
>>>

결과:

>>> qsort(ia, len(ia), sizeof(c_int), cmp_func)
py_cmp_func 5 1
py_cmp_func 33 99
py_cmp_func 7 33
py_cmp_func 5 7
py_cmp_func 1 7
>>>

이제 실제로 두 항목을 비교하여 유용한 결과를 반환할 수 있습니다:

>>> def py_cmp_func(a, b):
...     print("py_cmp_func", a[0], b[0])
...     return a[0] - b[0]
...
>>>
>>> qsort(ia, len(ia), sizeof(c_int), CMPFUNC(py_cmp_func))
py_cmp_func 5 1
py_cmp_func 33 99
py_cmp_func 7 33
py_cmp_func 1 7
py_cmp_func 5 7
>>>

쉽게 확인할 수 있듯이, 배열은 이제 정렬되었습니다:

>>> for i in ia: print(i, end=" ")
...
1 5 7 33 99
>>>

함수 팩토리는 데코레이터 팩토리로 사용할 수 있으므로, 다음과 같이 작성할 수도 있습니다:

>>> @CFUNCTYPE(c_int, POINTER(c_int), POINTER(c_int))
... def py_cmp_func(a, b):
...     print("py_cmp_func", a[0], b[0])
...     return a[0] - b[0]
...
>>> qsort(ia, len(ia), sizeof(c_int), py_cmp_func)
py_cmp_func 5 1
py_cmp_func 33 99
py_cmp_func 7 33
py_cmp_func 1 7
py_cmp_func 5 7
>>>

참고

C 코드에서 사용되는 동안 CFUNCTYPE() 객체에 대한 참조를 유지해야 합니다. ctypes가 참조를 유지하지는 않으며, 여러분이 하지 않는다면 가비지 수집되어, 콜백이 발생할 때 프로그램이 충돌할 수 있습니다.

또한, 콜백 함수가 파이썬 제어 바깥에서 만들어진 스레드(예를 들어, 콜백을 호출하는 외부 코드)에서 호출되면, ctypes는 모든 호출에 대해 새로운 더미 파이썬 스레드를 만듭니다. 이 동작은 대부분 적합하지만, threading.local에 저장된 값은, 같은 C 스레드에서 호출되는 여러 콜백에서 살아남을 수 없음을 뜻합니다.

dll에서 내 보낸 값을 액세스하기

Some shared libraries not only export functions, they also export variables. An example in the Python library itself is the Py_Version, Python runtime version number encoded in a single constant integer.

ctypes can access values like this with the in_dll() class methods of the type. pythonapi is a predefined symbol giving access to the Python C api:

>>> version = ctypes.c_int.in_dll(ctypes.pythonapi, "Py_Version")
>>> print(hex(version.value))
0x30c00a0

포인터의 사용법도 보여주는 확장 예제는 파이썬이 내 보낸 PyImport_FrozenModules 포인터에 액세스합니다.

해당 값에 대한 문서를 인용하면:

This pointer is initialized to point to an array of _frozen records, terminated by one whose members are all NULL or zero. When a frozen module is imported, it is searched in this table. Third-party code could play tricks with this to provide a dynamically created collection of frozen modules.

따라서, 이 포인터를 조작하는 것이 유용할 수도 있습니다. 예제 크기를 제한하기 위해, ctypes로 이 테이블을 읽는 방법만 보여줍니다:

>>> from ctypes import *
>>>
>>> class struct_frozen(Structure):
...     _fields_ = [("name", c_char_p),
...                 ("code", POINTER(c_ubyte)),
...                 ("size", c_int),
...                 ("get_code", POINTER(c_ubyte)),  # Function pointer
...                ]
...
>>>

We have defined the _frozen data type, so we can get the pointer to the table:

>>> FrozenTable = POINTER(struct_frozen)
>>> table = FrozenTable.in_dll(pythonapi, "_PyImport_FrozenBootstrap")
>>>

table이 struct_frozen 레코드의 배열에 대한 포인터이므로, 이터레이션할 수 있습니다. 하지만 포인터는 크기가 없으므로 루프를 종료하는 방법이 필요합니다. 조만간 액세스 위반 등으로 인해 충돌이 발생할 수 있으므로, NULL 엔트리가 발견되자마자 루프에서 벗어나는 것이 좋습니다:

>>> for item in table:
...     if item.name is None:
...         break
...     print(item.name.decode("ascii"), item.size)
...
_frozen_importlib 31764
_frozen_importlib_external 41499
zipimport 12345
>>>

표준 파이썬이 프로즌 모듈과 프로즌 패키지(음수 size 멤버로 표시됨)를 가지고 있다는 사실은 잘 알려지지 않았으며, 테스트용으로만 사용됩니다. 예를 들어 import __hello__를 시도해보십시오.

의외의 것들

ctypes에는 여러분이 기대하는 것과 실제로 일어나는 것이 다른 가장자리가 있습니다.

다음 예제를 고려해보십시오:

>>> from ctypes import *
>>> class POINT(Structure):
...     _fields_ = ("x", c_int), ("y", c_int)
...
>>> class RECT(Structure):
...     _fields_ = ("a", POINT), ("b", POINT)
...
>>> p1 = POINT(1, 2)
>>> p2 = POINT(3, 4)
>>> rc = RECT(p1, p2)
>>> print(rc.a.x, rc.a.y, rc.b.x, rc.b.y)
1 2 3 4
>>> # now swap the two points
>>> rc.a, rc.b = rc.b, rc.a
>>> print(rc.a.x, rc.a.y, rc.b.x, rc.b.y)
3 4 3 4
>>>

흠. 아마도 마지막 문장이 3 4 1 2를 인쇄할 것으로 기대했을 겁니다. 어떻게 된 걸까요? 위의 rc.a, rc.b = rc.b, rc.a 줄의 단계는 다음과 같습니다:

>>> temp0, temp1 = rc.b, rc.a
>>> rc.a = temp0
>>> rc.b = temp1
>>>

temp0 과 temp1은 여전히 위의 rc 객체의 내부 버퍼를 사용하는 객체입니다. 따라서 rc.a = temp0를 실행하면 temp0의 버퍼 내용이 rc의 버퍼로 복사됩니다. 이것은, 결과적으로 temp1의 내용을 변경합니다. 따라서 마지막 대입인 rc.b = temp1은 기대하는 효과를 주지 못합니다.

Structure, Union 및 Array에서 서브 객체를 가져오는 것은 서브 객체를 복사하지 않고, 대신 루트 객체의 하부 버퍼에 액세스하는 래퍼 객체를 가져온다는 점에 유의하십시오.

예상과 다른 행동을 하는 또 다른 예는 다음과 같습니다:

>>> s = c_char_p()
>>> s.value = b"abc def ghi"
>>> s.value
b'abc def ghi'
>>> s.value is s.value
False
>>>

참고

c_char_p로 인스턴스를 만든 객체는 바이트열이나 정수로 설정된 value만 가질 수 있습니다.

False를 인쇄하는 이유는 무엇일까요? ctypes 인스턴스는 메모리 블록과 메모리 내용에 액세스하는 어떤 디스크립터를 포함하는 객체입니다. 메모리 블록에 파이썬 객체를 저장하면 객체 자체를 저장하지 않고, 대신 객체의 내용을 저장합니다. 내용에 다시 액세스하면 매번 새로운 파이썬 객체가 생성됩니다!

가변 크기 데이터형

ctypes는 가변 크기 배열과 구조체에 대한 일부 지원을 제공합니다.

resize() 함수는 기존 ctypes 객체의 메모리 버퍼 크기를 바꾸는 데 사용할 수 있습니다. 이 함수는 객체를 첫 번째 인자로 가져오고, 바이트 단위의 요청 된 크기를 두 번째 인자로 가져옵니다. 메모리 블록을 객체 형이 지정하는 원래 메모리 블록보다 작게 만들 수 없습니다. 시도하면 ValueError가 발생합니다:

>>> short_array = (c_short * 4)()
>>> print(sizeof(short_array))
8
>>> resize(short_array, 4)
Traceback (most recent call last):
    ...
ValueError: minimum size is 8
>>> resize(short_array, 32)
>>> sizeof(short_array)
32
>>> sizeof(type(short_array))
8
>>>

훌륭합니다, 하지만 이 배열에 포함된 추가 요소에 어떻게 액세스할 수 있습니까? 형은 여전히 4개의 요소만 알고 있으므로, 다른 요소에 액세스하면 에러가 발생합니다:

>>> short_array[:]
[0, 0, 0, 0]
>>> short_array[7]
Traceback (most recent call last):
    ...
IndexError: invalid index
>>>

ctypes에서 가변 크기 데이터형을 사용하는 또 다른 방법은, 파이썬의 동적 특성을 사용하고 필요한 크기가 이미 알려진 후 매번 데이터형을 (재) 정의하는 것입니다.

ctypes 레퍼런스

공유 라이브러리 찾기

컴파일 언어로 프로그래밍할 때, 공유 라이브러리는 프로그램을 컴파일/링크할 때와 프로그램을 실행할 때 액세스 됩니다.

The purpose of the find_library() function is to locate a library in a way similar to what the compiler or runtime loader does (on platforms with several versions of a shared library the most recent should be loaded), while the ctypes library loaders act like when a program is run, and call the runtime loader directly.

The ctypes.util module provides a function which can help to determine the library to load.

ctypes.util.find_library(name)

라이브러리를 찾아서 경로명을 반환하려고 시도합니다. name은 lib 같은 접두사, .so, .dylib 또는 버전 번호와 같은 접미사가 없는 라이브러리 이름입니다 (이것은 posix 링커 옵션 -l에 사용되는 양식입니다). 라이브러리를 찾을 수 없으면 None을 반환합니다.

정확한 기능은 시스템에 따라 다릅니다.

On Linux, find_library() tries to run external programs (/sbin/ldconfig, gcc, objdump and ld) to find the library file. It returns the filename of the library file.

버전 3.6에서 변경: 리눅스에서, 다른 수단으로 라이브러리를 찾을 수 없으면, 라이브러리 검색 시 환경 변수 LD_LIBRARY_PATH의 값이 사용됩니다.

여기 예제가 있습니다:

>>> from ctypes.util import find_library
>>> find_library("m")
'libm.so.6'
>>> find_library("c")
'libc.so.6'
>>> find_library("bz2")
'libbz2.so.1.0'
>>>

On macOS and Android, find_library() uses the system’s standard naming schemes and paths to locate the library, and returns a full pathname if successful:

>>> from ctypes.util import find_library
>>> find_library("c")
'/usr/lib/libc.dylib'
>>> find_library("m")
'/usr/lib/libm.dylib'
>>> find_library("bz2")
'/usr/lib/libbz2.dylib'
>>> find_library("AGL")
'/System/Library/Frameworks/AGL.framework/AGL'
>>>

On Windows, find_library() searches along the system search path, and returns the full pathname, but since there is no predefined naming scheme a call like find_library("c") will fail and return None.

If wrapping a shared library with ctypes, it may be better to determine the shared library name at development time, and hardcode that into the wrapper module instead of using find_library() to locate the library at runtime.

공유 라이브러리 로드하기

공유 라이브러리를 파이썬 프로세스에 로드하는 방법에는 여러 가지가 있습니다. 한 가지 방법은 다음 클래스 중 하나의 인스턴스를 만드는 것입니다:

class ctypes.CDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)

Instances of this class represent loaded shared libraries. Functions in these libraries use the standard C calling convention, and are assumed to return int.

윈도우에서는 DLL 이름이 존재하더라도 CDLL 인스턴스 생성이 실패할 수 있습니다. 로드된 DLL의 종속 DLL을 찾을 수 없을 때, “[WinError 126] The specified module could not be found” 메시지로 OSError 에러가 발생합니다. 윈도우 API가 정보를 반환하지 않아서 이 에러 메시지에는 누락된 DLL의 이름이 포함되어 있지 않고, 이 에러를 진단하기 어렵게 만듭니다. 이 에러를 해결하고 찾을 수 없는 DLL을 확인하려면, 윈도우 디버깅과 추적 도구를 사용하여 종속 DLL 목록을 찾고 찾을 수 없는 DLL을 확인해야 합니다.

버전 3.12에서 변경: The name parameter can now be a path-like object.

더 보기

Microsoft DUMPBIN tool [https://docs.microsoft.com/cpp/build/reference/dependents] – DLL 종속 항목을 찾는 도구.

class ctypes.OleDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)

Instances of this class represent loaded shared libraries, functions in these libraries use the stdcall calling convention, and are assumed to return the windows specific HRESULT code. HRESULT values contain information specifying whether the function call failed or succeeded, together with additional error code. If the return value signals a failure, an OSError is automatically raised.

Availability: Windows

버전 3.3에서 변경: WindowsError used to be raised, which is now an alias of OSError.

버전 3.12에서 변경: The name parameter can now be a path-like object.

class ctypes.WinDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)

Instances of this class represent loaded shared libraries, functions in these libraries use the stdcall calling convention, and are assumed to return int by default.

Availability: Windows

버전 3.12에서 변경: The name parameter can now be a path-like object.

파이썬 전역 인터프리터 록은, 이 라이브러리들이 내보낸 함수를 호출하기 전에 해제되고 나중에 다시 획득됩니다.

class ctypes.PyDLL(name, mode=DEFAULT_MODE, handle=None)

이 클래스의 인스턴스는 CDLL 인스턴스처럼 동작합니다. 단, 파이썬 GIL이 함수 호출 중에 릴리스 되지 않고, 함수 실행 후 파이썬 에러 플래그가 확인된다는 점만 다릅니다. 에러 플래그가 설정되면 파이썬 예외가 발생합니다.

따라서, 이것은 파이썬 C API 함수를 직접 호출하는 경우에만 유용합니다.

버전 3.12에서 변경: The name parameter can now be a path-like object.

All these classes can be instantiated by calling them with at least one argument, the pathname of the shared library. If you have an existing handle to an already loaded shared library, it can be passed as the handle named parameter, otherwise the underlying platform’s dlopen() or LoadLibrary() function is used to load the library into the process, and to get a handle to it.

mode 매개 변수는 라이브러리가 로드되는 방법을 지정하는 데 사용될 수 있습니다. 자세한 내용은, dlopen(3) [https://manpages.debian.org/dlopen(3)] 매뉴얼 페이지를 참조하십시오. 윈도우에서는, mode가 무시됩니다. posix 시스템에서는 RTLD_NOW가 항상 추가되며 구성할 수 없습니다.

The use_errno parameter, when set to true, enables a ctypes mechanism that allows accessing the system errno error number in a safe way. ctypes maintains a thread-local copy of the system’s errno variable; if you call foreign functions created with use_errno=True then the errno value before the function call is swapped with the ctypes private copy, the same happens immediately after the function call.

ctypes.get_errno() 함수는 ctypes 내부 사본의 값을 반환하고, ctypes.set_errno() 함수는 ctypes 내부 사본을 새 값으로 변경하고 이전 값을 반환합니다.

The use_last_error parameter, when set to true, enables the same mechanism for the Windows error code which is managed by the GetLastError() and SetLastError() Windows API functions; ctypes.get_last_error() and ctypes.set_last_error() are used to request and change the ctypes private copy of the windows error code.

The winmode parameter is used on Windows to specify how the library is loaded (since mode is ignored). It takes any value that is valid for the Win32 API LoadLibraryEx flags parameter. When omitted, the default is to use the flags that result in the most secure DLL load, which avoids issues such as DLL hijacking. Passing the full path to the DLL is the safest way to ensure the correct library and dependencies are loaded.

버전 3.8에서 변경: winmode 매개 변수가 추가되었습니다.

ctypes.RTLD_GLOBAL

mode 매개 변수에 사용하는 플래그. 이 플래그를 사용할 수 없는 플랫폼에서는, 정수 0으로 정의됩니다.

ctypes.RTLD_LOCAL

mode 매개 변수에 사용하는 플래그. 이 플래그를 사용할 수 없는 플랫폼에서는, RTLD_GLOBAL과 같습니다.

ctypes.DEFAULT_MODE

공유 라이브러리를 로드하는 데 사용되는 기본 모드. OSX 10.3에서는 RTLD_GLOBAL이고, 그렇지 않으면 RTLD_LOCAL과 같습니다.

이 클래스들의 인스턴스는 공개 메서드가 없습니다. 공유 라이브러리가 내보낸 함수는 어트리뷰트나 인덱스로 액세스할 수 있습니다. 어트리뷰트를 통해 함수에 액세스하면 결과가 캐시 되므로 반복적으로 액세스할 때 매번 같은 객체가 반환됨에 유의하십시오. 반면에 인덱스를 통해 액세스하면 매번 새로운 객체가 반환됩니다:

>>> from ctypes import CDLL
>>> libc = CDLL("libc.so.6")  # On Linux
>>> libc.time == libc.time
True
>>> libc['time'] == libc['time']
False

다음 공개 어트리뷰트를 사용할 수 있습니다. 내보낸 함수 이름과의 충돌을 피하고자 이름은 밑줄로 시작합니다:

PyDLL._handle

라이브러리에 액세스하는 데 사용되는 시스템 핸들.

PyDLL._name

생성자에서 전달된 라이브러리의 이름.

Shared libraries can also be loaded by using one of the prefabricated objects, which are instances of the LibraryLoader class, either by calling the LoadLibrary() method, or by retrieving the library as attribute of the loader instance.

class ctypes.LibraryLoader(dlltype)

공유 라이브러리를 로드하는 클래스. dlltype은 CDLL, PyDLL, WinDLL 또는 OleDLL 형 중 하나여야 합니다.

__getattr__() has special behavior: It allows loading a shared library by accessing it as attribute of a library loader instance. The result is cached, so repeated attribute accesses return the same library each time.

LoadLibrary(name)

공유 라이브러리를 프로세스에 로드하고 반환합니다. 이 메서드는 항상 라이브러리의 새 인스턴스를 반환합니다.

다음과 같은 사전 작성된 로더를 사용할 수 있습니다:

ctypes.cdll

CDLL 인스턴스를 만듭니다.

ctypes.windll

Creates WinDLL instances.

Availability: Windows

ctypes.oledll

Creates OleDLL instances.

Availability: Windows

ctypes.pydll

PyDLL 인스턴스를 만듭니다.

C 파이썬 API에 직접 액세스하기 위해, 바로 사용할 수 있는 파이썬 공유 라이브러리 객체가 제공됩니다:

ctypes.pythonapi

An instance of PyDLL that exposes Python C API functions as attributes. Note that all these functions are assumed to return C int, which is of course not always the truth, so you have to assign the correct restype attribute to use these functions.

이러한 객체를 통해 라이브러리를 로드하면 라이브러리를 로드하는 데 사용된 이름인 name 문자열 인자로 감사 이벤트(auditing event) ctypes.dlopen을 발생시킵니다.

로드된 라이브러리에서 함수에 액세스하면 인자 library(라이브러리 객체)와 name(문자열이나 정수로 심볼의 이름)으로 감사 이벤트 ctypes.dlsym을 발생시킵니다.

객체 대신 라이브러리 핸들만 사용 가능한 경우, 함수에 액세스하면 인자 handle(원시 라이브러리 핸들)과 name으로 감사 이벤트 ctypes.dlsym/handle을 발생시킵니다.

외부 함수

As explained in the previous section, foreign functions can be accessed as attributes of loaded shared libraries. The function objects created in this way by default accept any number of arguments, accept any ctypes data instances as arguments, and return the default result type specified by the library loader.

They are instances of a private local class _FuncPtr (not exposed in ctypes) which inherits from the private _CFuncPtr class:

>>> import ctypes
>>> lib = ctypes.CDLL(None)
>>> issubclass(lib._FuncPtr, ctypes._CFuncPtr)
True
>>> lib._FuncPtr is ctypes._CFuncPtr
False

class ctypes._CFuncPtr

C 호출 가능한 외부 함수의 베이스 클래스.

외부 함수의 인스턴스는 C 호환 데이터형이기도 합니다; C 함수 포인터를 나타냅니다.

이 동작은 외부 함수 객체의 특수 어트리뷰트에 대입하여 사용자 정의할 수 있습니다.

restype

Assign a ctypes type to specify the result type of the foreign function. Use None for void, a function not returning anything.

It is possible to assign a callable Python object that is not a ctypes type, in this case the function is assumed to return a C int, and the callable will be called with this integer, allowing further processing or error checking. Using this is deprecated, for more flexible post processing or error checking use a ctypes data type as restype and assign a callable to the errcheck attribute.

argtypes

ctypes 형의 튜플을 대입하여 함수가 받아들이는 인자 형을 지정합니다. stdcall 호출 규칙을 사용하는 함수는 이 튜플의 길이와 같은 수의 인자로만 호출할 수 있습니다; C 호출 규칙을 사용하는 함수는 추가적인 지정되지 않은 인자도 허용합니다.

When a foreign function is called, each actual argument is passed to the from_param() class method of the items in the argtypes tuple, this method allows adapting the actual argument to an object that the foreign function accepts. For example, a c_char_p item in the argtypes tuple will convert a string passed as argument into a bytes object using ctypes conversion rules.

New: It is now possible to put items in argtypes which are not ctypes types, but each item must have a from_param() method which returns a value usable as argument (integer, string, ctypes instance). This allows defining adapters that can adapt custom objects as function parameters.

errcheck

이 어트리뷰트에 파이썬 함수나 다른 콜러블을 대입합니다. 콜러블은 3개 이상의 인자로 호출됩니다:

callable(result, func, arguments)

result is what the foreign function returns, as specified by the restype attribute.

func는 외부 함수 객체 자체이며, 같은 콜러블 객체를 재사용하여 여러 함수의 결과를 확인하거나 사후 처리할 수 있도록 합니다.

arguments는 원래 함수 호출에 전달된 매개 변수를 포함하는 튜플입니다. 사용된 인자에 따라 동작을 특수화할 수 있도록 합니다.

이 함수가 반환하는 객체는 외부 함수 호출에서 반환되지만, 결괏값을 확인하고 외부 함수 호출이 실패하면 예외를 발생시킬 수도 있습니다.

On Windows, when a foreign function call raises a system exception (for example, due to an access violation), it will be captured and replaced with a suitable Python exception. Further, an auditing event ctypes.set_exception with argument code will be raised, allowing an audit hook to replace the exception with its own.

외부 함수 호출을 일으키는 일부 방법은 인자 function pointer와 arguments로 감사 이벤트 ctypes.call_function를 발생시킬 수 있습니다.

함수 프로토타입

함수 프로토타입의 인스턴스를 만들어서 외부 함수를 만들 수도 있습니다. 함수 프로토타입은 C의 함수 프로토타입과 비슷합니다; 구현을 정의하지 않고 함수(반환형, 인자형, 호출 규칙)를 설명합니다. 팩토리 함수는 원하는 결과형과 함수의 인자형들로 호출되어야 하며, 데코레이터 팩토리로 사용되어 @wrapper 문법을 통해 함수에 적용될 수 있습니다. 예제는 콜백 함수를 참조하십시오.

ctypes.CFUNCTYPE(restype, *argtypes, use_errno=False, use_last_error=False)

반환된 함수 프로토타입은 표준 C 호출 규칙을 사용하는 함수를 만듭니다. 이 함수는 호출 중에 GIL을 해제합니다. use_errno를 참으로 설정하면, 시스템 errno 변수의 ctypes 내부 복사본이 호출 전후에 실제 errno 값과 교환됩니다; use_last_error는 윈도우 에러 코드에 대해 같은 일을 합니다.

ctypes.WINFUNCTYPE(restype, *argtypes, use_errno=False, use_last_error=False)

The returned function prototype creates functions that use the stdcall calling convention. The function will release the GIL during the call. use_errno and use_last_error have the same meaning as above.

Availability: Windows

ctypes.PYFUNCTYPE(restype, *argtypes)

반환된 함수 프로토타입은 파이썬 호출 규칙을 사용하는 함수를 만듭니다. 이 함수는 호출 도중 GIL을 해제하지 않습니다.

이러한 팩토리 함수로 만들어진 함수 프로토타입은 호출의 매개 변수 형과 수에 따라 다른 방법으로 인스턴스를 만들 수 있습니다:

prototype(address)

지정된 정수 주소에 있는 외부 함수를 반환합니다.

prototype(callable)

파이썬 callable로 C 호출 가능 함수(콜백 함수)를 만듭니다.

prototype(func_spec[, paramflags])

공유 라이브러리가 내보낸 외부 함수를 반환합니다. func_spec은 2-튜플 (name_or_ordinal, library) 여야 합니다. 첫 번째 항목은 내보낸 함수의 문자열 이름이거나, 작은 정수로 표현된 내보낸 함수의 서수(ordinal)입니다. 두 번째 항목은 공유 라이브러리 인스턴스입니다.

prototype(vtbl_index, name[, paramflags[, iid]])

COM 메서드를 호출할 외부 함수를 반환합니다. vtbl_index는 가상 함수 테이블에 대한 인덱스이며, 작은 음이 아닌 정수입니다. name은 COM 메서드의 이름입니다. iid는 확장 에러 보고에 사용되는 인터페이스 식별자를 가리키는 선택적 포인터입니다.

If iid is not specified, an OSError is raised if the COM method call fails. If iid is specified, a COMError is raised instead.

COM methods use a special calling convention: They require a pointer to the COM interface as first argument, in addition to those parameters that are specified in the argtypes tuple.

선택적 paramflags 매개 변수는 위에 설명된 기능보다 훨씬 많은 기능을 갖는 외부 함수 래퍼를 만듭니다.

paramflags must be a tuple of the same length as argtypes.

이 튜플의 각 항목에는 매개 변수에 대한 추가 정보가 들어 있으며, 한 개, 두 개 또는 세 개의 항목이 들어있는 튜플이어야 합니다.

첫 번째 항목은 매개 변수의 방향 플래그 조합을 포함하는 정수입니다:

1

함수에 대한 입력 매개 변수를 지정합니다.

2

출력 매개 변수. 외부 함수가 값을 채웁니다.

4

기본값이 정수 0인 입력 매개 변수.

선택적인 두 번째 항목은 문자열 매개 변수 이름입니다. 이것이 지정되면, 이름있는 매개 변수로 외부 함수를 호출할 수 있습니다.

선택적 세 번째 항목은 이 매개 변수의 기본값입니다.

The following example demonstrates how to wrap the Windows MessageBoxW function so that it supports default parameters and named arguments. The C declaration from the windows header file is this:

WINUSERAPI int WINAPI
MessageBoxW(
    HWND hWnd,
    LPCWSTR lpText,
    LPCWSTR lpCaption,
    UINT uType);

다음은 ctypes로 래핑하는 방법입니다:

>>> from ctypes import c_int, WINFUNCTYPE, windll
>>> from ctypes.wintypes import HWND, LPCWSTR, UINT
>>> prototype = WINFUNCTYPE(c_int, HWND, LPCWSTR, LPCWSTR, UINT)
>>> paramflags = (1, "hwnd", 0), (1, "text", "Hi"), (1, "caption", "Hello from ctypes"), (1, "flags", 0)
>>> MessageBox = prototype(("MessageBoxW", windll.user32), paramflags)

이제 MessageBox 외부 함수를 다음과 같이 호출할 수 있습니다.:

>>> MessageBox()
>>> MessageBox(text="Spam, spam, spam")
>>> MessageBox(flags=2, text="foo bar")

두 번째 예제는 출력 매개 변수를 보여줍니다. win32 GetWindowRect 함수는 지정된 창의 크기를 조회하는데, 호출자가 제공해야 하는 RECT 구조체로 복사합니다. 다음은 C 선언입니다:

WINUSERAPI BOOL WINAPI
GetWindowRect(
     HWND hWnd,
     LPRECT lpRect);

다음은 ctypes로 래핑하는 방법입니다:

>>> from ctypes import POINTER, WINFUNCTYPE, windll, WinError
>>> from ctypes.wintypes import BOOL, HWND, RECT
>>> prototype = WINFUNCTYPE(BOOL, HWND, POINTER(RECT))
>>> paramflags = (1, "hwnd"), (2, "lprect")
>>> GetWindowRect = prototype(("GetWindowRect", windll.user32), paramflags)
>>>

출력 매개 변수가 있는 함수는, 하나뿐이면 자동으로 출력 매개 변숫값을 반환하고, 여러 개면 출력 매개 변숫값을 포함하는 튜플을 반환하므로, GetWindowRect 함수는 이제 호출되면 RECT 인스턴스를 반환합니다.

Output parameters can be combined with the errcheck protocol to do further output processing and error checking. The win32 GetWindowRect api function returns a BOOL to signal success or failure, so this function could do the error checking, and raises an exception when the api call failed:

>>> def errcheck(result, func, args):
...     if not result:
...         raise WinError()
...     return args
...
>>> GetWindowRect.errcheck = errcheck
>>>

If the errcheck function returns the argument tuple it receives unchanged, ctypes continues the normal processing it does on the output parameters. If you want to return a tuple of window coordinates instead of a RECT instance, you can retrieve the fields in the function and return them instead, the normal processing will no longer take place:

>>> def errcheck(result, func, args):
...     if not result:
...         raise WinError()
...     rc = args[1]
...     return rc.left, rc.top, rc.bottom, rc.right
...
>>> GetWindowRect.errcheck = errcheck
>>>

유틸리티 함수

ctypes.addressof(obj)

메모리 버퍼의 주소를 정수로 반환합니다. obj는 ctypes 형의 인스턴스여야 합니다.

인자 obj로 감사 이벤트 ctypes.addressof를 발생시킵니다.

ctypes.alignment(obj_or_type)

ctypes 형의 정렬 요구 사항을 반환합니다. obj_or_type는 ctypes 형이나 인스턴스여야 합니다.

ctypes.byref(obj[, offset])

obj에 대한 경량 포인터를 반환합니다. obj는 ctypes 형의 인스턴스여야 합니다. offset의 기본값은 0이며, 내부 포인터 값에 더해질 정수여야 합니다.

byref(obj, offset)는 이 C 코드에 해당합니다:

(((char *)&obj) + offset)

반환된 객체는 외부 함수 호출 매개 변수로만 사용할 수 있습니다. pointer(obj)와 비슷하게 동작하지만, 훨씬 빨리 만들어집니다.

ctypes.cast(obj, type)

이 함수는 C의 형 변환 연산자와 유사합니다. obj와 같은 메모리 블록을 가리키는 type 형의 새 인스턴스를 반환합니다. type은 포인터형이어야 하며, obj는 포인터로 해석될 수 있는 객체여야 합니다.

ctypes.create_string_buffer(init_or_size, size=None)

이 함수는 가변 문자 버퍼를 만듭니다. 반환된 객체는 c_char의 ctypes 배열입니다.

init_or_size는 배열의 크기를 지정하는 정수거나 배열 항목을 초기화하는 데 사용될 바이트열 객체여야 합니다.

바이트열 객체가 첫 번째 인자로 지정되면, 버퍼의 길이는 이 객체의 길이보다 한 항목만큼 길어져서, 배열의 마지막 요소가 NUL 종료 문자가 됩니다. 두 번째 인자로 정수를 전달하면 바이트열의 길이를 사용하지 않고 배열의 크기를 지정할 수 있습니다.

init, size 인자로 감사 이벤트 ctypes.create_string_buffer를 발생시킵니다.

ctypes.create_unicode_buffer(init_or_size, size=None)

이 함수는 가변 유니코드 문자 버퍼를 만듭니다. 반환된 객체는 c_wchar의 ctypes 배열입니다.

init_or_size는 배열의 크기를 지정하는 정수거나 배열 항목을 초기화하는 데 사용될 문자열이어야 합니다.

문자열이 첫 번째 인자로 지정되면, 버퍼의 길이는 문자열의 길이보다 한 항목만큼 길어져서, 배열의 마지막 요소가 NUL 종료 문자가 됩니다. 두 번째 인자로 정수를 전달하면 문자열의 길이를 사용하지 않고 배열의 크기를 지정할 수 있습니다.

init, size 인자로 감사 이벤트 ctypes.create_unicode_buffer를 발생시킵니다.

ctypes.DllCanUnloadNow()

This function is a hook which allows implementing in-process COM servers with ctypes. It is called from the DllCanUnloadNow function that the _ctypes extension dll exports.

Availability: Windows

ctypes.DllGetClassObject()

This function is a hook which allows implementing in-process COM servers with ctypes. It is called from the DllGetClassObject function that the _ctypes extension dll exports.

Availability: Windows

ctypes.util.find_library(name)

라이브러리를 찾아서 경로명을 반환하려고 시도합니다. name은 lib 같은 접두사, .so, .dylib 또는 버전 번호와 같은 접미사가 없는 라이브러리 이름입니다 (이것은 posix 링커 옵션 -l에 사용되는 양식입니다). 라이브러리를 찾을 수 없으면 None을 반환합니다.

정확한 기능은 시스템에 따라 다릅니다.

ctypes.util.find_msvcrt()

Returns the filename of the VC runtime library used by Python, and by the extension modules. If the name of the library cannot be determined, None is returned.

예를 들어, free(void *)에 대한 호출로 확장 모듈에 의해 할당된 메모리를 해제해야 하면, 메모리를 할당한 것과 같은 라이브러리에 있는 함수를 사용하는 것이 중요합니다.

Availability: Windows

ctypes.FormatError([code])

Returns a textual description of the error code code. If no error code is specified, the last error code is used by calling the Windows api function GetLastError.

Availability: Windows

ctypes.GetLastError()

Returns the last error code set by Windows in the calling thread. This function calls the Windows GetLastError() function directly, it does not return the ctypes-private copy of the error code.

Availability: Windows

ctypes.get_errno()

호출하는 스레드에서 시스템 errno 변수의 ctypes 내부 복사본의 현재 값을 반환합니다.

인자 없이 감사 이벤트 ctypes.get_errno를 발생시킵니다.

ctypes.get_last_error()

Returns the current value of the ctypes-private copy of the system LastError variable in the calling thread.

Availability: Windows

인자 없이 감사 이벤트 ctypes.get_last_error를 발생시킵니다.

ctypes.memmove(dst, src, count)

표준 C memmove 라이브러리 함수와 같습니다: count 바이트를 src에서 dst로 복사합니다. dst 와 src는 정수이거나 포인터로 변환할 수 있는 ctypes 인스턴스여야 합니다.

ctypes.memset(dst, c, count)

표준 C memset 라이브러리 함수와 같습니다: 주소 dst의 메모리 블록을 값 c의 count 바이트로 채웁니다. dst는 주소를 지정하는 정수거나 ctypes 인스턴스여야 합니다.

ctypes.POINTER(type, /)

Create and return a new ctypes pointer type. Pointer types are cached and reused internally, so calling this function repeatedly is cheap. type must be a ctypes type.

ctypes.pointer(obj, /)

Create a new pointer instance, pointing to obj. The returned object is of the type POINTER(type(obj)).

참고 사항: 객체에 대한 포인터를 단지 외부 함수 호출로 전달하려면 훨씬 빠른 byref(obj)를 사용해야 합니다.

ctypes.resize(obj, size)

이 함수는 obj의 내부 메모리 버퍼의 크기를 조정합니다. obj는 ctypes 형의 인스턴스여야 합니다. sizeof(type(obj))로 주어지는 객체 형의 원래 크기보다 버퍼를 작게 만들 수는 없지만, 버퍼를 확대할 수 있습니다.

ctypes.set_errno(value)

호출 중인 스레드의 시스템 errno 변수의 ctypes 내부 복사본의 현재 값을 value로 설정하고 이전 값을 반환합니다.

인자 errno로 감사 이벤트 ctypes.set_errno를 발생시킵니다.

ctypes.set_last_error(value)

Sets the current value of the ctypes-private copy of the system LastError variable in the calling thread to value and return the previous value.

Availability: Windows

인자 error로 감사 이벤트 ctypes.set_last_error를 발생시킵니다.

ctypes.sizeof(obj_or_type)

ctypes 형이나 인스턴스 메모리 버퍼의 크기를 바이트 단위로 반환합니다. C sizeof 연산자와 같은 일을 합니다.

ctypes.string_at(ptr, size=-1)

Return the byte string at void *ptr. If size is specified, it is used as size, otherwise the string is assumed to be zero-terminated.

Raises an auditing event ctypes.string_at with arguments ptr, size.

ctypes.WinError(code=None, descr=None)

This function is probably the worst-named thing in ctypes. It creates an instance of OSError. If code is not specified, GetLastError is called to determine the error code. If descr is not specified, FormatError() is called to get a textual description of the error.

Availability: Windows

버전 3.3에서 변경: An instance of WindowsError used to be created, which is now an alias of OSError.

ctypes.wstring_at(ptr, size=-1)

Return the wide-character string at void *ptr. If size is specified, it is used as the number of characters of the string, otherwise the string is assumed to be zero-terminated.

Raises an auditing event ctypes.wstring_at with arguments ptr, size.

데이터형

class ctypes._CData

이 비공개 클래스는 모든 ctypes 데이터형의 공통 베이스 클래스입니다. 무엇보다도, 모든 ctypes 형 인스턴스에는 C 호환 데이터를 보관하는 메모리 블록이 포함됩니다; 메모리 블록의 주소는 addressof() 도우미 함수에 의해 반환됩니다. 다른 인스턴스 변수는 _objects로 노출됩니다; 여기에는 메모리 블록에 포인터가 포함되어있을 때, 살려둘 필요가 있는 다른 파이썬 객체가 포함되어 있습니다.

ctypes 데이터형의 공통 메서드, 이것들은 모두 클래스 메서드입니다 (정확히 말하면, 메타 클래스의 메서드입니다):

from_buffer(source[, offset])

이 메서드는 source 객체의 버퍼를 공유하는 ctypes 인스턴스를 반환합니다. source 객체는 쓰기 가능한 버퍼 인터페이스를 지원해야 합니다. 선택적 offset 매개 변수는 source 버퍼의 오프셋을 바이트 단위로 지정합니다; 기본값은 0입니다. source 버퍼가 충분히 크지 않으면 ValueError가 발생합니다.

인자 pointer, size, offset으로 감사 이벤트 ctypes.cdata/buffer를 발생시킵니다.

from_buffer_copy(source[, offset])

이 메서드는 읽을 수 있어야 하는 source 객체 버퍼에서 버퍼를 복사하여 ctypes 인스턴스를 만듭니다. 선택적 offset 매개 변수는 원본 버퍼의 오프셋을 바이트 단위로 지정합니다. 기본값은 0입니다. 소스 버퍼가 충분히 크지 않으면 ValueError가 발생합니다.

인자 pointer, size, offset으로 감사 이벤트 ctypes.cdata/buffer를 발생시킵니다.

from_address(address)

이 메서드는 정수 address로 지정된 메모리를 사용하여 ctypes 형 인스턴스를 반환합니다.

이 메서드와 이 메서드를 간접적으로 호출하는 다른 것들은 인자 address로 감사 이벤트 ctypes.cdata를 발생시킵니다.

from_param(obj)

This method adapts obj to a ctypes type. It is called with the actual object used in a foreign function call when the type is present in the foreign function’s argtypes tuple; it must return an object that can be used as a function call parameter.

모든 ctypes 데이터형은 이 클래스 메서드의 기본 구현을 갖는데, obj 가 이 형의 인스턴스면 obj 를 반환합니다. 일부 형은 다른 객체도 허용합니다.

in_dll(library, name)

이 메서드는 공유 라이브러리가 내보낸 ctypes 형 인스턴스를 반환합니다. name은 데이터를 내보내는 심볼의 이름이고, library는 로드된 공유 라이브러리입니다.

ctypes 데이터형의 공통 인스턴스 변수:

_b_base_

때로 ctypes 데이터 인스턴스는 포함하는 메모리 블록을 소유하지 않고, 베이스 객체의 메모리 블록의 일부를 공유합니다. _b_base_ 읽기 전용 멤버는 메모리 블록을 소유한 루트 ctypes 객체입니다.

_b_needsfree_

이 읽기 전용 변수는 ctypes 데이터 인스턴스가 메모리 블록을 스스로 할당했을 때 참이고, 그렇지 않으면 거짓입니다.

_objects

이 멤버는 None 이거나 메모리 블록 내용이 계속 유효하도록 유지되어야 하는 파이썬 객체를 포함하는 딕셔너리입니다. 이 객체는 디버깅을 위해서만 노출됩니다; 이 딕셔너리의 내용을 수정하지 마십시오.

기본 데이터형

class ctypes._SimpleCData

이 비공개 클래스는 모든 기본 ctypes 데이터형의 베이스 클래스입니다. 여기에는 기본 ctypes 데이터형의 공통 어트리뷰트가 들어 있으므로 여기에서 언급합니다. _SimpleCData는 _CData의 서브 클래스이므로, 메서드와 어트리뷰트를 상속받습니다. 포인터가 아니고 포인터를 포함하지 않는 ctypes 데이터형을 이제 피클 할 수 있습니다.

인스턴스에는 어트리뷰트가 하나 있습니다:

value

이 어트리뷰트는 인스턴스의 실제 값을 포함합니다. 정수형과 포인터형에서는 정수고, 문자형에서는 단일 문자 바이트열 객체나 문자열이고, 문자 포인터형에서는 파이썬 바이트열 객체나 문자열입니다.

ctypes 인스턴스에서 value 어트리뷰트를 조회하면, 대개 매번 새 객체가 반환됩니다. ctypes는 원래의 객체 반환을 구현하지 않습니다. 항상 새로운 객체가 만들어집니다. 다른 모든 ctypes 객체 인스턴스에서도 마찬가지입니다.

Fundamental data types, when returned as foreign function call results, or, for example, by retrieving structure field members or array items, are transparently converted to native Python types. In other words, if a foreign function has a restype of c_char_p, you will always receive a Python bytes object, not a c_char_p instance.

Subclasses of fundamental data types do not inherit this behavior. So, if a foreign functions restype is a subclass of c_void_p, you will receive an instance of this subclass from the function call. Of course, you can get the value of the pointer by accessing the value attribute.

다음은 기본 ctypes 데이터형입니다:

class ctypes.c_byte

Represents the C signed char datatype, and interprets the value as small integer. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_char

Represents the C char datatype, and interprets the value as a single character. The constructor accepts an optional string initializer, the length of the string must be exactly one character.

class ctypes.c_char_p

Represents the C char* datatype when it points to a zero-terminated string. For a general character pointer that may also point to binary data, POINTER(c_char) must be used. The constructor accepts an integer address, or a bytes object.

class ctypes.c_double

Represents the C double datatype. The constructor accepts an optional float initializer.

class ctypes.c_longdouble

Represents the C long double datatype. The constructor accepts an optional float initializer. On platforms where sizeof(long double) == sizeof(double) it is an alias to c_double.

class ctypes.c_float

Represents the C float datatype. The constructor accepts an optional float initializer.

class ctypes.c_double_complex

Represents the C double complex datatype, if available. The constructor accepts an optional complex initializer.

Added in version 3.14.

class ctypes.c_float_complex

Represents the C float complex datatype, if available. The constructor accepts an optional complex initializer.

Added in version 3.14.

class ctypes.c_longdouble_complex

Represents the C long double complex datatype, if available. The constructor accepts an optional complex initializer.

Added in version 3.14.

class ctypes.c_int

Represents the C signed int datatype. The constructor accepts an optional integer initializer; no overflow checking is done. On platforms where sizeof(int) == sizeof(long) it is an alias to c_long.

class ctypes.c_int8

Represents the C 8-bit signed int datatype. Usually an alias for c_byte.

class ctypes.c_int16

Represents the C 16-bit signed int datatype. Usually an alias for c_short.

class ctypes.c_int32

Represents the C 32-bit signed int datatype. Usually an alias for c_int.

class ctypes.c_int64

Represents the C 64-bit signed int datatype. Usually an alias for c_longlong.

class ctypes.c_long

Represents the C signed long datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_longlong

Represents the C signed long long datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_short

Represents the C signed short datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_size_t

C size_t 데이터형을 나타냅니다.

class ctypes.c_ssize_t

C ssize_t 데이터형을 나타냅니다.

Added in version 3.2.

class ctypes.c_time_t

Represents the C time_t datatype.

Added in version 3.12.

class ctypes.c_ubyte

Represents the C unsigned char datatype, it interprets the value as small integer. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_uint

Represents the C unsigned int datatype. The constructor accepts an optional integer initializer; no overflow checking is done. On platforms where sizeof(int) == sizeof(long) it is an alias for c_ulong.

class ctypes.c_uint8

Represents the C 8-bit unsigned int datatype. Usually an alias for c_ubyte.

class ctypes.c_uint16

Represents the C 16-bit unsigned int datatype. Usually an alias for c_ushort.

class ctypes.c_uint32

Represents the C 32-bit unsigned int datatype. Usually an alias for c_uint.

class ctypes.c_uint64

Represents the C 64-bit unsigned int datatype. Usually an alias for c_ulonglong.

class ctypes.c_ulong

Represents the C unsigned long datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_ulonglong

Represents the C unsigned long long datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_ushort

Represents the C unsigned short datatype. The constructor accepts an optional integer initializer; no overflow checking is done.

class ctypes.c_void_p

Represents the C void* type. The value is represented as integer. The constructor accepts an optional integer initializer.

class ctypes.c_wchar

C wchar_t 데이터형을 나타내고, 값을 단일 문자 유니코드 문자열로 해석합니다. 생성자는 선택적 문자열 초기화자를 받아들입니다, 문자열의 길이는 정확히 한 문자여야 합니다.

class ctypes.c_wchar_p

Represents the C wchar_t* datatype, which must be a pointer to a zero-terminated wide character string. The constructor accepts an integer address, or a string.

class ctypes.c_bool

Represent the C bool datatype (more accurately, _Bool from C99). Its value can be True or False, and the constructor accepts any object that has a truth value.

class ctypes.HRESULT

Represents a HRESULT value, which contains success or error information for a function or method call.

Availability: Windows

class ctypes.py_object

Represents the C PyObject* datatype. Calling this without an argument creates a NULL PyObject* pointer.

The ctypes.wintypes module provides quite some other Windows specific data types, for example HWND, WPARAM, or DWORD. Some useful structures like MSG or RECT are also defined.

구조화된 데이터형

class ctypes.Union(*args, **kw)

네이티브 바이트 순서의 공용체를 위한 추상 베이스 클래스.

Unions share common attributes and behavior with structures; see Structure documentation for details.

class ctypes.BigEndianUnion(*args, **kw)

Abstract base class for unions in big endian byte order.

Added in version 3.11.

class ctypes.LittleEndianUnion(*args, **kw)

Abstract base class for unions in little endian byte order.

Added in version 3.11.

class ctypes.BigEndianStructure(*args, **kw)

빅엔디안(big endian) 바이트 순서의 구조체를 위한 추상 베이스 클래스.

class ctypes.LittleEndianStructure(*args, **kw)

리틀엔디안(little endian) 바이트 순서로의 구조체를 위한 추상 베이스 클래스.

Structures and unions with non-native byte order cannot contain pointer type fields, or any other data types containing pointer type fields.

class ctypes.Structure(*args, **kw)

네이티브 바이트 순서의 구조체를 위한 추상 베이스 클래스.

구상 구조체와 공용체 형은 이 형 중 하나를 서브 클래싱하고 적어도 _fields_ 클래스 변수를 정의해서 만들어야 합니다. ctypes는 직접 어트리뷰트 액세스로 필드를 읽고 쓸 수 있는 디스크립터를 만듭니다. 이것들은

_fields_

구조체 필드를 정의하는 시퀀스. 항목은 2-튜플이나 3-튜플이어야 합니다. 첫 번째 항목은 필드의 이름이고, 두 번째 항목은 필드의 형을 지정합니다; 모든 ctypes 데이터형이 될 수 있습니다.

c_int와 같은 정수형 필드에서는, 세 번째 선택적 항목을 지정할 수 있습니다. 필드의 비트 폭을 정의하는 작은 양의 정수여야 합니다.

필드 이름은 하나의 구조체나 공용체 내에서 고유해야 합니다. 이것은 검사되지 않습니다, 이름이 중복되면 하나의 필드만 액세스할 수 있습니다.

_fields_ 클래스 변수를, Structure 서브 클래스를 정의하는 클래스 문 뒤에서 정의할 수 있습니다. 직접 또는 간접적으로 자신을 참조하는 데이터형을 만들 수 있게 합니다:

class List(Structure):
    pass
List._fields_ = [("pnext", POINTER(List)),
                 ...
                ]

The _fields_ class variable can only be set once. Later assignments will raise an AttributeError.

Additionally, the _fields_ class variable must be defined before the structure or union type is first used: an instance or subclass is created, sizeof() is called on it, and so on. Later assignments to _fields_ will raise an AttributeError. If _fields_ has not been set before such use, the structure or union will have no own fields, as if _fields_ was empty.

Sub-subclasses of structure types inherit the fields of the base class plus the _fields_ defined in the sub-subclass, if any.

_pack_

An optional small integer that allows overriding the alignment of structure fields in the instance. _pack_ must already be defined when _fields_ is assigned, otherwise it will have no effect. Setting this attribute to 0 is the same as not setting it at all.

_align_

An optional small integer that allows overriding the alignment of the structure when being packed or unpacked to/from memory. Setting this attribute to 0 is the same as not setting it at all.

Added in version 3.13.

_layout_

An optional string naming the struct/union layout. It can currently be set to:

"ms": the layout used by the Microsoft compiler (MSVC). On GCC and Clang, this layout can be selected with __attribute__((ms_struct)).

"gcc-sysv": the layout used by GCC with the System V or “SysV-like” data model, as used on Linux and macOS. With this layout, _pack_ must be unset or zero.

If not set explicitly, ctypes will use a default that matches the platform conventions. This default may change in future Python releases (for example, when a new platform gains official support, or when a difference between similar platforms is found). Currently the default will be:

On Windows: "ms"

When _pack_ is specified: "ms"

Otherwise: "gcc-sysv"

_layout_ must already be defined when _fields_ is assigned, otherwise it will have no effect.

_anonymous_

이름 없는(익명) 필드의 이름을 나열하는 선택적 시퀀스. _fields_가 대입될 때 _anonymous_는 이미 정의되어 있어야 합니다. 그렇지 않으면 아무 효과가 없습니다.

이 변수에 나열된 필드는 구조체나 공용체 형 필드여야 합니다. ctypes는 구조체나 공용체 필드를 만들 필요 없이, 중첩된 필드에 직접 액세스할 수 있는 디스크립터를 구조체 형에 만듭니다.

다음은 예제 형입니다 (윈도우):

class _U(Union):
    _fields_ = [("lptdesc", POINTER(TYPEDESC)),
                ("lpadesc", POINTER(ARRAYDESC)),
                ("hreftype", HREFTYPE)]

class TYPEDESC(Structure):
    _anonymous_ = ("u",)
    _fields_ = [("u", _U),
                ("vt", VARTYPE)]

TYPEDESC 구조체는 COM 데이터형을 설명합니다. vt 필드는 공용체 필드 중 어느 것이 유효한지 지정합니다. u 필드가 익명 필드로 정의되었으므로, 이제 TYPEDESC 인스턴스에서 멤버에 직접 액세스할 수 있습니다. td.lptdesc와 td.u.lptdesc는 동등하지만, 앞에 있는 것이 임시 공용체 인스턴스를 만들 필요가 없으므로 더 빠릅니다:

td = TYPEDESC()
td.vt = VT_PTR
td.lptdesc = POINTER(some_type)
td.u.lptdesc = POINTER(some_type)

구조체 형의 서브-서브 클래스를 정의할 수 있으며, 베이스 클래스의 필드를 상속합니다. 서브 클래스 정의에 별도의 _fields_ 변수가 있으면, 여기에 지정된 필드가 베이스 클래스의 필드에 추가됩니다.

구조체와 공용체 생성자는 위치와 키워드 인자를 모두 받아들입니다. 위치 인자는 _fields_에 나타나는 순서대로 멤버 필드를 초기화하는 데 사용됩니다. 생성자의 키워드 인자는 어트리뷰트 대입으로 해석되므로, _fields_를 같은 이름으로 초기화하거나, _fields_에 없는 이름에 대한 새 어트리뷰트를 만듭니다.

배열과 포인터

class ctypes.Array(*args)

배열의 추상 베이스 클래스.

The recommended way to create concrete array types is by multiplying any ctypes data type with a non-negative integer. Alternatively, you can subclass this type and define _length_ and _type_ class variables. Array elements can be read and written using standard subscript and slice accesses; for slice reads, the resulting object is not itself an Array.

_length_

배열의 요소 수를 지정하는 양의 정수. 범위를 벗어나는 서브 스크립트는 IndexError를 일으킵니다. len()에 의해 반환됩니다.

_type_

배열의 각 요소 형을 지정합니다.

Array 서브 클래스 생성자는 요소를 순서대로 초기화하는 데 사용되는 위치 인자를 받아들입니다.

ctypes.ARRAY(type, length)

Create an array. Equivalent to type * length, where type is a ctypes data type and length an integer.

This function is soft deprecated in favor of multiplication. There are no plans to remove it.

class ctypes._Pointer

포인터를 위한 내부 추상 베이스 클래스.

구상 포인터형은 가리킬 형으로 POINTER()를 호출해서 만들어집니다; 이것은 pointer()에 의해 자동으로 수행됩니다.

포인터가 배열을 가리키면, 그것의 요소는 표준 서브 스크립트 및 슬라이스 액세스를 사용하여 읽고 쓸 수 있습니다. 포인터 객체는 크기가 없으므로, len()는 TypeError를 발생시킵니다. 음수 서브 스크립트는 (C처럼) 포인터 앞의 메모리를 읽을 것이고, 범위를 벗어나는 서브 스크립트는 (운이 좋다면) 액세스 위반으로 인해 충돌을 일으킬 것입니다.

_type_

가리키는 형을 지정합니다.

contents

포인터가 가리키는 객체를 반환합니다. 이 어트리뷰트에 대입하면 대입된 객체를 가리키도록 포인터가 변경됩니다.

Exceptions

exception ctypes.ArgumentError

외부 함수 호출이 전달된 인자 중 하나를 변환할 수 없을 때 발생하는 예외.

exception ctypes.COMError(hresult, text, details)

This exception is raised when a COM method call failed.

hresult

The integer value representing the error code.

text

The error message.

details

The 5-tuple (descr, source, helpfile, helpcontext, progid).

descr is the textual description. source is the language-dependent ProgID for the class or application that raised the error. helpfile is the path of the help file. helpcontext is the help context identifier. progid is the ProgID of the interface that defined the error.

Availability: Windows

Added in version 3.14.0a2 (unreleased).

동시 실행

이 장에서 설명하는 모듈은 코드의 동시 실행을 지원합니다. 적절한 도구 선택은 실행할 작업(CPU 병목 대 IO 병목)과 선호하는 개발 스타일(이벤트 구동 협력적 다중작업 대 선점적 다중작업)에 따라 달라집니다. 다음은 개요입니다:

threading — Thread-based parallelism

active_count()

current_thread()

excepthook()

__excepthook__

get_ident()

get_native_id()

enumerate()

main_thread()

settrace()

settrace_all_threads()

gettrace()

setprofile()

setprofile_all_threads()

getprofile()

stack_size()

TIMEOUT_MAX

스레드 로컬 데이터

local

Thread 객체

Thread

start()

run()

join()

name

getName()

setName()

ident

native_id

is_alive()

daemon

isDaemon()

setDaemon()

Lock 객체

Lock

acquire()

release()

locked()

RLock 객체

RLock

acquire()

release()

Condition 객체

Condition

acquire()

release()

wait()

wait_for()

notify()

notify_all()

Semaphore 객체

Semaphore

acquire()

release()

BoundedSemaphore

Semaphore 예

Event 객체

Event

is_set()

set()

clear()

wait()

Timer 객체

Timer

cancel()

Barrier 객체

Barrier

wait()

reset()

abort()

parties

n_waiting

broken

BrokenBarrierError

with 문으로 록, 조건 및 세마포어 사용하기

multiprocessing — Process-based parallelism

소개

Process 클래스

컨텍스트 및 시작 방법

프로세스 간 객체 교환

프로세스 간 동기화

프로세스 간 상태 공유

작업자 풀 사용

레퍼런스

Process와 예외

Process

run()

start()

join()

name

is_alive()

daemon

pid

exitcode

authkey

sentinel

terminate()

kill()

close()

ProcessError

BufferTooShort

AuthenticationError

TimeoutError

파이프와 큐

Pipe()

Queue

qsize()

empty()

full()

put()

put_nowait()

get()

get_nowait()

close()

join_thread()

cancel_join_thread()

SimpleQueue

close()

empty()

get()

put()

JoinableQueue

task_done()

join()

잡동사니

active_children()

cpu_count()

current_process()

parent_process()

freeze_support()

get_all_start_methods()

get_context()

get_start_method()

set_executable()

set_forkserver_preload()

set_start_method()

Connection 객체

Connection

send()

recv()

fileno()

close()

poll()

send_bytes()

recv_bytes()

recv_bytes_into()

동기화 프리미티브

Barrier

BoundedSemaphore

Condition

Event

Lock

acquire()

release()

RLock

acquire()

release()

Semaphore

공유 ctypes 객체

Value()

Array()

multiprocessing.sharedctypes 모듈

RawArray()

RawValue()

Array()

Value()

copy()

synchronized()

관리자

Manager()

BaseManager

start()

get_server()

connect()

shutdown()

register()

address

SyncManager

Barrier()

BoundedSemaphore()

Condition()

Event()

Lock()

Namespace()

Queue()

RLock()

Semaphore()

Array()

Value()

dict()

list()

Namespace

사용자 정의 관리자

원격 관리자 사용하기

프락시 객체

BaseProxy

_callmethod()

_getvalue()

__repr__()

__str__()

정리

프로세스 풀

Pool

apply()

apply_async()

map()

map_async()

imap()

imap_unordered()

starmap()

starmap_async()

close()

terminate()

join()

AsyncResult

get()

wait()

ready()

successful()

리스너와 클라이언트

deliver_challenge()

answer_challenge()

Client()

Listener

accept()

close()

address

last_accepted

wait()

주소 형식

인증 키

로깅

get_logger()

log_to_stderr()

multiprocessing.dummy 모듈

ThreadPool

프로그래밍 지침

모든 시작 방법

spawn 과 forkserver 시작 방법

예제

multiprocessing.shared_memory — Shared memory for direct access across processes

SharedMemory

close()

unlink()

buf

name

size

SharedMemoryManager

SharedMemory()

ShareableList()

ShareableList

count()

index()

format

shm

The concurrent package

concurrent.futures — Launching parallel tasks

Executor 객체

Executor

submit()

map()

shutdown()

ThreadPoolExecutor

ThreadPoolExecutor

ThreadPoolExecutor 예제

InterpreterPoolExecutor

InterpreterPoolExecutor

ProcessPoolExecutor

ProcessPoolExecutor

ProcessPoolExecutor 예제

Future 객체

Future

cancel()

cancelled()

running()

done()

result()

exception()

add_done_callback()

set_running_or_notify_cancel()

set_result()

set_exception()

모듈 함수

wait()

FIRST_COMPLETED

FIRST_EXCEPTION

ALL_COMPLETED

as_completed()

예외 클래스

CancelledError

TimeoutError

BrokenExecutor

InvalidStateError

BrokenThreadPool

BrokenInterpreterPool

ExecutionFailed

BrokenProcessPool

subprocess — Subprocess management

subprocess 모듈 사용하기

run()

CompletedProcess

args

returncode

stdout

stderr

check_returncode()

DEVNULL

PIPE

STDOUT

SubprocessError

TimeoutExpired

cmd

timeout

output

stdout

stderr

CalledProcessError

returncode

cmd

output

stdout

stderr

자주 사용되는 인자

Popen 생성자

Popen

예외

보안 고려 사항

Popen 객체

poll()

wait()

communicate()

send_signal()

terminate()

kill()

args

stdin

stdout

stderr

pid

returncode

윈도우 Popen 도우미

STARTUPINFO

dwFlags

hStdInput

hStdOutput

hStdError

wShowWindow

lpAttributeList

윈도우 상수

STD_INPUT_HANDLE

STD_OUTPUT_HANDLE

STD_ERROR_HANDLE

SW_HIDE

STARTF_USESTDHANDLES

STARTF_USESHOWWINDOW

STARTF_FORCEONFEEDBACK

STARTF_FORCEOFFFEEDBACK

CREATE_NEW_CONSOLE

CREATE_NEW_PROCESS_GROUP

ABOVE_NORMAL_PRIORITY_CLASS

BELOW_NORMAL_PRIORITY_CLASS

HIGH_PRIORITY_CLASS

IDLE_PRIORITY_CLASS

NORMAL_PRIORITY_CLASS

REALTIME_PRIORITY_CLASS

CREATE_NO_WINDOW

DETACHED_PROCESS

CREATE_DEFAULT_ERROR_MODE

CREATE_BREAKAWAY_FROM_JOB

오래된 고수준 API

call()

check_call()

check_output()

이전 함수를 subprocess 모듈로 교체하기

/bin/sh 셸 명령 치환 교체하기

셸 파이프라인 교체하기

os.system() 교체하기

os.spawn 패밀리 교체하기

Replacing os.popen()

레거시 셸 호출 함수

getstatusoutput()

getoutput()

노트

윈도우에서 인자 시퀀스를 문자열로 변환하기

Disable use of posix_spawn()

sched — Event scheduler

scheduler

스케줄러 객체

enterabs()

enter()

cancel()

empty()

run()

queue

queue — A synchronized queue class

Queue

LifoQueue

PriorityQueue

SimpleQueue

Empty

Full

ShutDown

큐 객체

qsize()

empty()

full()

put()

put_nowait()

get()

get_nowait()

task_done()

join()

Terminating queues

shutdown()

SimpleQueue 객체

qsize()

empty()

put()

put_nowait()

get()

get_nowait()

contextvars — Context Variables

컨텍스트 변수

ContextVar

name

get()

set()

reset()

Token

var

old_value

MISSING

수동 컨텍스트 관리

copy_context()

Context

run()

copy()

get()

keys()

values()

items()

asyncio 지원

다음은 위 서비스 중 일부에 대한 지원 모듈입니다:

_thread — Low-level threading API

error

LockType

start_new_thread()

interrupt_main()

exit()

allocate_lock()

get_ident()

get_native_id()

stack_size()

TIMEOUT_MAX

acquire()

release()

locked()

threading — Thread-based parallelism

소스 코드: Lib/threading.py [https://github.com/python/cpython/tree/main/Lib/threading.py]

This module constructs higher-level threading interfaces on top of the lower level _thread module.

버전 3.7에서 변경: 이 모듈은 선택 사양이었지만, 이제는 항상 사용 가능합니다.

더 보기

concurrent.futures.ThreadPoolExecutor offers a higher level interface to push tasks to a background thread without blocking execution of the calling thread, while still being able to retrieve their results when needed.

queue provides a thread-safe interface for exchanging data between running threads.

asyncio offers an alternative approach to achieving task level concurrency without requiring the use of multiple operating system threads.

참고

In the Python 2.x series, this module contained camelCase names for some methods and functions. These are deprecated as of Python 3.10, but they are still supported for compatibility with Python 2.5 and lower.

CPython 구현 상세: CPython에서는, 전역 인터프리터 록으로 인해 한 번에 하나의 스레드만 파이썬 코드를 실행할 수 있습니다 (설사 일부 성능 지향 라이브러리가 이 제한을 극복할 수 있을지라도). 응용 프로그램에서 멀티 코어 기계의 계산 자원을 더 잘 활용하려면 multiprocessing이나 concurrent.futures.ProcessPoolExecutor를 사용하는 것이 좋습니다. 그러나, 여러 I/O 병목 작업을 동시에 실행하고 싶을 때 threading은 여전히 적절한 모델입니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

이 모듈은 다음 함수를 정의합니다:

threading.active_count()

현재 살아있는 Thread 객체 수를 반환합니다. 반환된 수는 enumerate()가 반환한 리스트의 길이와 같습니다.

The function activeCount is a deprecated alias for this function.

threading.current_thread()

호출자의 제어 스레드에 해당하는 현재 Thread 객체를 반환합니다. 호출자의 제어 스레드가 threading 모듈을 통해 만들어지지 않았으면, 기능이 제한된 더미 스레드 객체가 반환됩니다.

The function currentThread is a deprecated alias for this function.

threading.excepthook(args, /)

Thread.run()에 의해 발생한 포착되지 않은 예외를 처리합니다.

args 인자에는 다음과 같은 어트리뷰트가 있습니다:

exc_type: 예외 형.

exc_value: 예외 값, None일 수 있습니다.

exc_traceback: 예외 트레이스백, None일 수 있습니다.

thread: 예외를 발생시킨 스레드, None일 수 있습니다.

exc_type이 SystemExit이면, 예외는 조용히 무시됩니다. 그렇지 않으면, sys.stderr에 예외가 인쇄됩니다.

이 함수에서 예외가 발생하면, 이를 처리하기 위해 sys.excepthook()이 호출됩니다.

Thread.run()에 의해 발생한 포착되지 않은 예외를 처리하는 방법을 제어하기 위해 threading.excepthook()을 재정의할 수 있습니다.

사용자 정의 훅을 사용하여 exc_value를 저장하면 참조 순환을 만들 수 있습니다. 예외가 더는 필요하지 않을 때 참조 순환을 끊기 위해 명시적으로 지워야 합니다.

사용자 정의 훅을 사용하여 thread를 저장하면 파이널라이즈 중인 객체로 설정되면 이를 되살릴 수 있습니다. 객체를 되살리는 것을 방지하려면 사용자 정의 훅이 완료된 후 thread를 보관하지 마십시오.

더 보기

sys.excepthook()은 포착되지 않은 예외를 처리합니다.

Added in version 3.8.

threading.__excepthook__

Holds the original value of threading.excepthook(). It is saved so that the original value can be restored in case they happen to get replaced with broken or alternative objects.

Added in version 3.10.

threading.get_ident()

현재 스레드의 ‘스레드 식별자’를 반환합니다. 이것은 0이 아닌 정수입니다. 이 값은 직접적인 의미가 없습니다; 이것은 매직 쿠키로 사용하려는 것입니다, 예를 들어 스레드 특정 데이터의 딕셔너리를 인덱싱하는 데 사용됩니다. 스레드 식별자는 스레드가 종료되고 다른 스레드가 만들어질 때 재활용될 수 있습니다.

Added in version 3.3.

threading.get_native_id()

커널이 할당한 현재 스레드의 네이티브 정수 스레드 ID를 반환합니다. 음수가 아닌 정수입니다. 이 값은 시스템 전체에서 이 특정 스레드를 고유하게 식별하는 데 사용될 수 있습니다 (스레드가 종료될 때까지, 그 후에는 OS에서 값을 재활용할 수 있습니다).

Availability: Windows, FreeBSD, Linux, macOS, OpenBSD, NetBSD, AIX, DragonFlyBSD, GNU/kFreeBSD.

Added in version 3.8.

버전 3.13에서 변경: Added support for GNU/kFreeBSD.

threading.enumerate()

Return a list of all Thread objects currently active. The list includes daemonic threads and dummy thread objects created by current_thread(). It excludes terminated threads and threads that have not yet been started. However, the main thread is always part of the result, even when terminated.

threading.main_thread()

메인 Thread 객체를 반환합니다. 정상적인 조건에서, 메인 스레드는 파이썬 인터프리터가 시작된 스레드입니다.

Added in version 3.4.

threading.settrace(func)

threading 모듈에서 시작된 모든 스레드에 대한 추적 함수를 설정합니다. func는 run() 메서드가 호출되기 전에 각 스레드에 대해 sys.settrace()로 전달됩니다.

threading.settrace_all_threads(func)

Set a trace function for all threads started from the threading module and all Python threads that are currently executing.

The func will be passed to sys.settrace() for each thread, before its run() method is called.

Added in version 3.12.

threading.gettrace()

Get the trace function as set by settrace().

Added in version 3.10.

threading.setprofile(func)

threading 모듈에서 시작된 모든 스레드에 대한 프로파일 함수를 설정합니다. func는 run() 메서드가 호출되기 전에 각 스레드에 대해 sys.setprofile()로 전달됩니다.

threading.setprofile_all_threads(func)

Set a profile function for all threads started from the threading module and all Python threads that are currently executing.

The func will be passed to sys.setprofile() for each thread, before its run() method is called.

Added in version 3.12.

threading.getprofile()

Get the profiler function as set by setprofile().

Added in version 3.10.

threading.stack_size([size])

새 스레드를 만들 때 사용된 스레드 스택 크기를 반환합니다. 선택적 size 인자는 이후에 만들어지는 스레드에 사용할 스택 크기를 지정하며, 0(플랫폼이나 구성된 기본값을 사용합니다)이거나 32,768 (32 KiB) 이상의 양의 정숫값이어야 합니다. size를 지정하지 않으면, 0이 사용됩니다. 스레드 스택 크기 변경이 지원되지 않으면, RuntimeError가 발생합니다. 지정된 스택 크기가 유효하지 않으면, ValueError가 발생하고 스택 크기는 수정되지 않습니다. 32 KiB는 현재 인터프리터 자체에 충분한 스택 공간을 보장하기 위해 지원되는 최소 스택 크기 값입니다. 최소 스택 크기가 32 KiB 보다 커야 한다거나 시스템 메모리 페이지 크기의 배수로 할당해야 하는 등 일부 플랫폼에는 스택 크기 값에 대한 특정 제한이 있을 수 있습니다 - 자세한 내용은 플랫폼 설명서를 참조하십시오 (4 KiB 페이지는 흔합니다; 스택 크기에 4096의 배수를 사용하는 것이 더 구체적인 정보가 없을 때 제안하는 방법입니다).

Availability: Windows, pthreads.

Unix platforms with POSIX threads support.

이 모듈은 또한 다음 상수를 정의합니다:

threading.TIMEOUT_MAX

블로킹 함수(Lock.acquire(), RLock.acquire(), Condition.wait() 등)의 timeout 매개 변수에 허용되는 최댓값. 이 값보다 큰 timeout을 지정하면 OverflowError가 발생합니다.

Added in version 3.2.

이 모듈은 아래 섹션에 자세히 설명되는 많은 클래스를 정의합니다.

이 모듈의 설계는 Java의 스레딩 모델에 약하게 기반합니다. 그러나, Java가 록(locks)과 조건 변수(condition variables)를 모든 객체의 기본 동작으로 만들지만, 파이썬에서는 별도의 객체입니다. 파이썬의 Thread 클래스는 Java Thread 클래스 동작의 부분 집합을 지원합니다; 현재, 우선순위가 없고, 스레드 그룹이 없으며 스레드를 파괴, 중지, 일시 중지, 재개 또는 인터럽트 할 수 없습니다. 구현될 때, Java 스레드 클래스의 정적 메서드는 모듈 수준 함수에 매핑됩니다.

아래에 설명된 모든 메서드는 원자 적으로 실행됩니다.

스레드 로컬 데이터

스레드 로컬 데이터는 값이 스레드에만 한정되는 데이터입니다. 스레드 로컬 데이터를 관리하려면, local(또는 서브 클래스) 인스턴스를 만들고 그것에 어트리뷰트를 저장하십시오:

mydata = threading.local()
mydata.x = 1

인스턴스 값은 개별 스레드마다 다릅니다.

class threading.local

스레드 로컬 데이터를 나타내는 클래스.

For more details and extensive examples, see the documentation string of the _threading_local module: Lib/_threading_local.py [https://github.com/python/cpython/tree/main/Lib/_threading_local.py].

Thread 객체

The Thread class represents an activity that is run in a separate thread of control. There are two ways to specify the activity: by passing a callable object to the constructor, or by overriding the run() method in a subclass. No other methods (except for the constructor) should be overridden in a subclass. In other words, only override the __init__() and run() methods of this class.

일단 스레드 객체가 만들어지면, 스레드의 start() 메서드를 호출하여 활동을 시작해야 합니다. 이것은 별도의 제어 스레드에서 run() 메서드를 호출합니다.

일단 스레드의 활동이 시작되면, 스레드는 ‘살아있는(alive)’ 것으로 간주합니다. run() 메서드가 정상적으로 혹은 처리되지 않은 예외를 발생시켜서 종료할 때 살아있음을 멈춥니다. is_alive() 메서드는 스레드가 살아있는지 검사합니다.

다른 스레드는 스레드의 join() 메서드를 호출할 수 있습니다. 이것은 join() 메서드가 호출된 스레드가 종료될 때까지 호출하는 스레드를 블록 합니다.

스레드에는 이름이 있습니다. 이름은 생성자에 전달되고, name 어트리뷰트를 통해 읽거나 변경할 수 있습니다.

run() 메서드에서 예외가 발생하면, 이를 처리하기 위해 threading.excepthook()이 호출됩니다. 기본적으로, threading.excepthook()은 SystemExit를 조용히 무시합니다.

스레드는 “데몬 스레드”로 플래그 할 수 있습니다. 이 플래그의 의미는 오직 데몬 스레드만 남았을 때 전체 파이썬 프로그램이 종료된다는 것입니다. 초깃값은 만드는 스레드에서 상속됩니다. 플래그는 daemon 프로퍼티나 daemon 생성자 인자를 통해 설정할 수 있습니다.

참고

종료 시 데몬 스레드는 갑자기 중지됩니다. 그들의 자원(가령 열린 파일, 데이터베이스 트랜잭션 등)은 제대로 해제되지 않을 수 있습니다. 스레드가 우아하게 중지되도록 하려면, 스레드를 데몬이 아니도록 만들고 Event와 같은 적절한 신호 메커니즘을 사용하십시오.

“메인 스레드” 객체가 있습니다; 이것은 파이썬 프로그램의 초기 제어 스레드에 해당합니다. 이것은 데몬 스레드가 아닙니다.

There is the possibility that “dummy thread objects” are created. These are thread objects corresponding to “alien threads”, which are threads of control started outside the threading module, such as directly from C code. Dummy thread objects have limited functionality; they are always considered alive and daemonic, and cannot be joined. They are never deleted, since it is impossible to detect the termination of alien threads.

class threading.Thread(group=None, target=None, name=None, args=(), kwargs={}, *, daemon=None)

이 생성자는 항상 키워드 인자로 호출해야 합니다. 인자는 다음과 같습니다:

group should be None; reserved for future extension when a ThreadGroup class is implemented.

target은 run() 메서드에 의해 호출될 콜러블 객체입니다. 기본값은 None이며, 아무것도 호출되지 않습니다.

name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number, or “Thread-N (target)” where “target” is target.__name__ if the target argument is specified.

args is a list or tuple of arguments for the target invocation. Defaults to ().

kwargs는 target 호출을 위한 키워드 인자의 딕셔너리입니다. 기본값은 {}입니다.

None이 아니면, daemon은 스레드가 데몬인지를 명시적으로 설정합니다. None(기본값)이면, 데몬 속성은 현재 스레드에서 상속됩니다.

서브 클래스가 생성자를 재정의하면, 스레드에 다른 작업을 수행하기 전에 베이스 클래스 생성자(Thread.__init__())를 호출해야 합니다.

버전 3.3에서 변경: Added the daemon parameter.

버전 3.10에서 변경: Use the target name if name argument is omitted.

start()

스레드 활동을 시작합니다.

스레드 객체 당 최대 한 번 호출되어야 합니다. 객체의 run() 메서드가 별도의 제어 스레드에서 호출되도록 배치합니다.

이 메서드는 같은 스레드 객체에서 두 번 이상 호출되면, RuntimeError를 발생시킵니다.

run()

스레드의 활동을 표현하는 메서드.

서브 클래스에서 이 메서드를 재정의할 수 있습니다. 표준 run() 메서드는 target 인자로 객체의 생성자에 전달된 콜러블 객체를 호출합니다, 있다면 args와 kwargs 인자에서 각각 취한 위치와 키워드 인자로 호출합니다.

Using list or tuple as the args argument which passed to the Thread could achieve the same effect.

Example:

>>> from threading import Thread
>>> t = Thread(target=print, args=[1])
>>> t.run()
1
>>> t = Thread(target=print, args=(1,))
>>> t.run()
1

join(timeout=None)

스레드가 종료할 때까지 기다립니다. join() 메서드가 호출된 스레드가 정상적으로 혹은 처리되지 않은 예외를 통해 종료하거나 선택적 시간제한 초과가 발생할 때까지 호출하는 스레드를 블록 합니다.

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

timeout 인자가 없거나 None이면, 스레드가 종료될 때까지 작업이 블록 됩니다.

A thread can be joined many times.

교착 상태를 유발할 수 있어서 현재 스레드를 조인하려고 시도하면 join()은 RuntimeError를 발생시킵니다. 스레드가 시작되기 전에 join() 하는 것도 에러이고 같은 예외가 발생합니다.

name

식별 목적으로만 사용되는 문자열. 의미는 없습니다. 여러 스레드에 같은 이름을 지정할 수 있습니다. 초기 이름은 생성자가 설정합니다.

getName()

setName()

Deprecated getter/setter API for name; use it directly as a property instead.

버전 3.10부터 폐지됨.

ident

이 스레드의 ‘스레드 식별자’ 또는 스레드가 시작되지 않았으면 None. 이것은 0이 아닌 정수입니다. get_ident() 함수를 참조하십시오. 스레드 식별자는 스레드가 종료되고 다른 스레드가 만들어질 때 재활용될 수 있습니다. 스레드가 종료된 후에도 식별자를 사용할 수 있습니다.

native_id

The Thread ID (TID) of this thread, as assigned by the OS (kernel). This is a non-negative integer, or None if the thread has not been started. See the get_native_id() function. This value may be used to uniquely identify this particular thread system-wide (until the thread terminates, after which the value may be recycled by the OS).

참고

프로세스 ID 와 유사하게, 스레드 ID는 스레드가 만들어진 시점부터 스레드가 종료될 때까지만 유효(시스템 전체에서 고유함이 보장)합니다.

Availability: Windows, FreeBSD, Linux, macOS, OpenBSD, NetBSD, AIX, DragonFlyBSD.

Added in version 3.8.

is_alive()

스레드가 살아있는지를 반환합니다.

이 메서드는 run() 메서드가 시작되기 직전부터 run() 메서드가 종료된 직후까지 True를 반환합니다. 모듈 함수 enumerate()는 모든 살아있는 스레드 리스트를 반환합니다.

daemon

A boolean value indicating whether this thread is a daemon thread (True) or not (False). This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

살아있는 데몬이 아닌 스레드가 남아 있지 않으면 전체 파이썬 프로그램이 종료됩니다.

isDaemon()

setDaemon()

Deprecated getter/setter API for daemon; use it directly as a property instead.

버전 3.10부터 폐지됨.

Lock 객체

프리미티브 록(primitive lock)은 잠겨있을 때 특정 스레드가 소유하지 않는 동기화 프리미티브입니다. 파이썬에서는 현재 _thread 확장 모듈에 의해 직접 구현되는 가장 낮은 수준의 동기화 프리미티브입니다.

프리미티브 록은 두 상태 중 하나입니다, “잠금(locked)”이나 “잠금 해제(unlocked)”. 잠금 해제 상태로 만들어집니다. 두 가지 기본 메서드가 있습니다, acquire()와 release(). 상태가 잠금 해제일 때, acquire()는 상태를 잠금으로 변경하고 즉시 반환합니다. 상태가 잠금일 때, acquire()는 다른 스레드에서의 release()에 호출이 잠금 해제로 변경할 때까지 블록 된 후, acquire() 호출이 이를 잠금으로 재설정하고 반환합니다. release() 메서드는 잠금 상태에서만 호출해야 합니다; 상태를 잠금 해제로 변경하고 즉시 반환합니다. 잠금 해제된 록을 해제하려고 하면, RuntimeError가 발생합니다.

록은 컨텍스트 관리자 프로토콜도 지원합니다.

둘 이상의 스레드가 acquire()에서 블록 되어 상태가 잠금 해제가 되기를 기다릴 때, release() 호출이 상태를 잠금 해제로 재설정하면 하나의 스레드만 진행됩니다; 대기 중인 스레드 중 어느 것이 진행하는지는 정의되지 않았으며, 구현에 따라 다를 수 있습니다.

모든 메서드는 원자 적으로 실행됩니다.

class threading.Lock

프리미티브 록 객체를 구현하는 클래스. 일단 스레드가 록을 획득하면, 이후에 해당 록을 확보하려고 시도하면 해제될 때까지 블록 합니다; 모든 스레드가 해제할 수 있습니다.

버전 3.13에서 변경: Lock is now a class. In earlier Pythons, Lock was a factory function which returned an instance of the underlying private lock type.

acquire(blocking=True, timeout=-1)

블로킹이거나 비 블로킹으로, 록을 획득합니다.

blocking 인자를 True(기본값)로 설정하여 호출하면, 록이 잠금 해제될 때까지 블록 한 다음, 잠금으로 설정하고 True를 반환합니다.

blocking 인자를 False로 설정하여 호출하면, 블록 하지 않습니다. blocking이 True로 설정된 호출이 블록 될 것이라면, 즉시 False를 반환합니다; 그렇지 않으면, 록을 잠금으로 설정하고 True를 반환합니다.

When invoked with the floating-point timeout argument set to a positive value, block for at most the number of seconds specified by timeout and as long as the lock cannot be acquired. A timeout argument of -1 specifies an unbounded wait. It is forbidden to specify a timeout when blocking is False.

록이 성공적으로 획득되면 반환 값은 True이고, 그렇지 않으면 (예를 들어 timeout이 만료되면) False입니다.

버전 3.2에서 변경: timeout 매개 변수가 추가되었습니다.

버전 3.2에서 변경: 하부 스레딩 구현이 지원한다면 POSIX에서 시그널로 록 획득을 중단할 수 있습니다.

버전 3.14에서 변경: Lock acquisition can now be interrupted by signals on Windows.

release()

록을 해제합니다. 록을 획득한 스레드뿐만 아니라 모든 스레드에서 호출할 수 있습니다.

록이 잠금일 때, 잠금 해제로 재설정하고 반환합니다. 록이 잠금 해제될 때까지 다른 스레드가 블록 되어 기다리고 있으면, 그들 중 정확히 하나의 스레드가 진행되도록 합니다.

잠금 해제된 록에서 호출되면, RuntimeError가 발생합니다.

반환 값이 없습니다.

locked()

Return True if the lock is acquired.

RLock 객체

재진입 록(reentrant lock)은 같은 스레드에 의해 여러 번 획득될 수 있는 동기화 프리미티브입니다. 내부적으로, 프리미티브 록에서 사용하는 잠금/잠금 해제 상태에 더해 “소유하는 스레드(owning thread)”와 “재귀 수준(recursion level)” 개념을 사용합니다. 잠금 상태에서는, 어떤 스레드가 록을 소유합니다; 잠금 해제 상태에서는 아무런 스레드도 록을 소유하지 않습니다.

Threads call a lock’s acquire() method to lock it, and its release() method to unlock it.

참고

Reentrant locks support the context management protocol, so it is recommended to use with instead of manually calling acquire() and release() to handle acquiring and releasing the lock for a block of code.

RLock’s acquire()/release() call pairs may be nested, unlike Lock’s acquire()/release(). Only the final release() (the release() of the outermost pair) resets the lock to an unlocked state and allows another thread blocked in acquire() to proceed.

acquire()/release() must be used in pairs: each acquire must have a release in the thread that has acquired the lock. Failing to call release as many times the lock has been acquired can lead to deadlock.

class threading.RLock

이 클래스는 재진입 록 객체를 구현합니다. 재진입 록은 획득한 스레드에서 해제해야 합니다. 일단 스레드가 재진입 록을 획득하면, 같은 스레드는 블록 하지 않고 다시 스레드를 획득할 수 있습니다; 스레드는 획득할 때마다 한 번씩 해제해야 합니다.

RLock은 실제로는 플랫폼에서 지원하는 가장 효율적인 버전의 구상 RLock 클래스 인스턴스를 반환하는 팩토리 함수임에 유의하십시오.

acquire(blocking=True, timeout=-1)

블로킹이거나 비 블로킹으로, 록을 획득합니다.

더 보기

Using RLock as a context manager

Recommended over manual acquire() and release() calls whenever practical.

When invoked with the blocking argument set to True (the default):

If no thread owns the lock, acquire the lock and return immediately.

If another thread owns the lock, block until we are able to acquire lock, or timeout, if set to a positive float value.

If the same thread owns the lock, acquire the lock again, and return immediately. This is the difference between Lock and RLock; Lock handles this case the same as the previous, blocking until the lock can be acquired.

When invoked with the blocking argument set to False:

If no thread owns the lock, acquire the lock and return immediately.

If another thread owns the lock, return immediately.

If the same thread owns the lock, acquire the lock again and return immediately.

In all cases, if the thread was able to acquire the lock, return True. If the thread was unable to acquire the lock (i.e. if not blocking or the timeout was reached) return False.

If called multiple times, failing to call release() as many times may lead to deadlock. Consider using RLock as a context manager rather than calling acquire/release directly.

버전 3.2에서 변경: timeout 매개 변수가 추가되었습니다.

release()

재귀 수준을 낮추면서, 잠금을 해제합니다. 감소 후에 0이 되면, 록을 잠금 해제로 (아무런 스레드도 소유하지 않은) 재설정하고, 록이 잠금 해제되도록 기다리면서 블록 된 다른 스레드가 있으면, 그중 정확히 하나가 진행되도록 합니다. 감소 후에 재귀 수준이 여전히 0이 아니면, 록은 잠금이고, 호출하는 스레드에 의해 소유된 채로 유지됩니다.

Only call this method when the calling thread owns the lock. A RuntimeError is raised if this method is called when the lock is not acquired.

반환 값이 없습니다.

Condition 객체

조건 변수(condition variable)는 항상 어떤 종류의 록과 연관됩니다; 이것은 전달되거나 기본적으로 만들어집니다. 전달하는 것은 여러 조건 변수가 같은 록을 공유해야 할 때 유용합니다. 록은 조건 객체의 일부입니다: 별도로 추적할 필요가 없습니다.

조건 변수는 컨텍스트 관리자 프로토콜을 준수합니다: with 문을 사용해서 감싼 블록의 지속 시간 동안 연관된 록을 획득합니다. acquire()와 release() 메서드도 연관된 록의 해당 메서드를 호출합니다.

다른 메서드들은 연관된 록을 잡은 상태에서 호출해야 합니다. wait() 메서드는 록을 해제한 다음, 다른 스레드가 notify()나 notify_all()을 호출하여 록을 해제할 때까지 블록 합니다. 일단 깨어나면, wait()는 록을 다시 획득하고 반환합니다. 시간제한을 지정할 수도 있습니다.

notify() 메서드는 있다면 조건 변수를 기다리는 스레드 중 하나를 깨웁니다. notify_all() 메서드는 조건 변수를 기다리는 모든 스레드를 깨웁니다.

참고: notify()와 notify_all() 메서드는 록을 해제하지 않습니다; 이것은 깨어난 스레드나 스레드들이 wait() 호출에서 즉시 반환되지 않지만, notify()나 notify_all()을 호출한 스레드가 최종적으로 록 소유권을 포기할 때만 반환됨을 의미합니다.

조건 변수를 사용하는 일반적인 프로그래밍 스타일은 록을 사용하여 어떤 공유 상태에 대한 액세스를 동기화합니다; 특정 상태 변경에 관심 있는 스레드는 원하는 상태를 볼 때까지 wait()를 반복적으로 호출하는 반면, 상태를 변경하는 스레드는 대기자 중 하나가 원하는 상태일 수 있도록 상태를 변경할 때 notify()나 notify_all()을 호출합니다. 예를 들어, 다음 코드는 무제한 버퍼 용량의 일반적인 생산자-소비자 상황입니다:

# Consume one item
with cv:
    while not an_item_is_available():
        cv.wait()
    get_an_available_item()

# Produce one item
with cv:
    make_an_item_available()
    cv.notify()

wait()가 임의의 긴 시간 후에 반환될 수 있고, notify() 호출을 유발한 조건이 더는 참이 아닐 수 있기 때문에, 응용 프로그램의 조건에 대한 while 루프 검사가 필요합니다. 이것은 다중 스레드 프로그래밍에 본질적으로 수반됩니다. wait_for() 메서드를 사용하면 조건 검사를 자동화하고 시간제한 계산을 쉽게 수행할 수 있습니다:

# Consume an item
with cv:
    cv.wait_for(an_item_is_available)
    get_an_available_item()

notify()와 notify_all() 중에서 선택하려면, 하나의 상태 변경에 흥미 있는 대기 중인 스레드가 하나일지 여러 개일지를 고려하십시오. 예를 들어 일반적인 생산자-소비자 상황에서, 하나의 항목을 버퍼에 추가하면 오직 하나의 소비자 스레드만 깨울 필요가 있습니다.

class threading.Condition(lock=None)

이 클래스는 조건 변수 객체를 구현합니다. 조건 변수를 사용하면 하나 이상의 스레드가 다른 스레드에 의해 통지될 때까지 기다릴 수 있습니다.

lock 인자가 제공되고 None이 아니면, Lock이나 RLock 객체여야 하며, 하부 록으로 사용됩니다. 그렇지 않으면, 새 RLock 객체가 만들어지고 하부 록으로 사용됩니다.

버전 3.3에서 변경: 팩토리 함수에서 클래스로 변경되었습니다.

acquire(*args)

하부 록을 획득합니다. 이 메서드는 하부 록에서 해당 메서드를 호출합니다; 반환 값은 그 메서드가 반환하는 것입니다.

release()

하부 록을 해제합니다. 이 메서드는 하부 록에서 해당 메서드를 호출합니다; 반환 값이 없습니다.

wait(timeout=None)

통지되거나 시간제한이 만료될 때까지 기다립니다. 이 메서드가 호출될 때 호출하는 스레드가 록을 획득하지 않았으면, RuntimeError가 발생합니다.

이 메서드는 하부 록을 해제한 다음, 같은 조건 변수에 대한 다른 스레드에서의 notify()나 notify_all() 호출에 의해 깨어날 때까지 또는 선택적 시간제한 만료가 발생할 때까지 블록 합니다. 일단 깨어나거나 시간제한이 만료되면, 록을 다시 획득하고 반환합니다.

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds (or fractions thereof).

하부 록이 RLock일 때, 록이 여러 번 재귀적으로 획득되었을 때 록을 실제로 잠금 해제하지 못할 수 있기 때문에, release() 메서드를 사용하여 록을 해제하지 않습니다. 대신, RLock 클래스의 내부 인터페이스가 사용되어, 재귀적으로 여러 번 획득한 경우에도 실제로 록을 잠금 해제합니다. 그런 다음 다른 내부 인터페이스를 사용하여 록을 다시 획득할 때 재귀 수준을 복원합니다.

주어진 timeout이 만료되지 않는 한 반환 값은 True이며, 만료되면 False입니다.

버전 3.2에서 변경: 이전에는, 메서드가 항상 None을 반환했습니다.

wait_for(predicate, timeout=None)

조건이 참으로 평가될 때까지 기다립니다. predicate는 불리언 값으로 해석될 결과를 반환하는 콜러블 이어야 합니다. 최대 대기 시간을 주는 timeout이 제공될 수 있습니다.

이 유틸리티 메서드는 술어(predicate)가 충족될 때까지, 또는 시간제한 만료가 발생할 때까지 wait()를 반복적으로 호출할 수 있습니다. 반환 값은 predicate의 마지막 반환 값이며 메서드가 시간제한 만료되면 False로 평가됩니다.

시간제한 기능을 무시할 때, 이 메서드를 호출하는 것은 대략 다음과 같이 작성하는 것과 동등합니다:

while not predicate():
    cv.wait()

따라서, wait()와 같은 규칙이 적용됩니다: 호출될 때 록을 잡고 있어야 하며 반환할 때 다시 확보됩니다. predicate는 록을 잡고 있는 상태로 평가됩니다.

Added in version 3.2.

notify(n=1)

기본적으로, (있다면) 이 조건에서 대기 중인 하나의 스레드를 깨웁니다. 이 메서드가 호출될 때 호출하는 스레드가 잠금을 획득하지 않았으면 RuntimeError가 발생합니다.

이 메서드는 조건 변수를 기다리는 스레드를 최대 n 개 깨웁니다; 기다리는 스레드가 없으면 아무런 일도 하지 않습니다.

적어도 n 스레드가 대기 중이면, 현재 구현은 정확히 n 스레드를 깨웁니다. 그러나, 이 동작에 의존하는 것은 안전하지 않습니다. 미래에는, 최적화된 구현이 때때로 n 스레드보다 많이 깨울 수 있습니다.

참고: 깨어난 스레드는 록을 다시 획득할 때까지 wait() 호출에서 실제로 반환하지 않습니다. notify()가 록을 해제하지 않기 때문에, 호출자가 해제해야 합니다.

notify_all()

이 조건에서 대기 중인 모든 스레드를 깨웁니다. 이 메서드는 notify()처럼 작동하지만, 하나 대신에 대기 중인 모든 스레드를 깨웁니다. 이 메서드가 호출될 때 호출하는 스레드가 잠금을 획득하지 않았으면 RuntimeError가 발생합니다.

The method notifyAll is a deprecated alias for this method.

Semaphore 객체

이것은 일찌감치 네덜란드 컴퓨터 과학자 Edsger W. Dijkstra가 발명한, 컴퓨터 과학 역사상 가장 오래된 동기화 프리미티브 중 하나입니다 (그는 acquire()와 release() 대신 P()와 V()라는 이름을 사용했습니다).

세마포어는 각 acquire() 호출에 의해 감소하고 각 release() 호출에 의해 증가하는 내부 카운터를 관리합니다. 카운터는 절대 0 밑으로 떨어질 수 없습니다; acquire()가 0임을 발견하면, 다른 스레드가 release()를 호출할 때까지 대기하면서 블록 합니다.

세마포어도 컨텍스트 관리자 프로토콜을 지원합니다.

class threading.Semaphore(value=1)

이 클래스는 세마포어 객체를 구현합니다. 세마포어는 release() 호출 수에서 acquire() 호출 수를 빼고, 초깃값을 더한 원자 적 카운터를 관리합니다. acquire() 메서드는 카운터를 음수로 만들지 않고 반환할 수 있을 때까지 필요하면 블록 합니다. 지정하지 않으면, value의 기본값은 1입니다.

선택적 인자는 내부 카운터의 초깃 값(value)을 제공합니다; 기본값은 1입니다. 주어진 value가 0보다 작으면 ValueError가 발생합니다.

버전 3.3에서 변경: 팩토리 함수에서 클래스로 변경되었습니다.

acquire(blocking=True, timeout=None)

세마포어를 획득합니다.

인자 없이 호출될 때:

진입 시 내부 카운터가 0보다 크면, 1 감소시키고 즉시 True를 반환합니다.

진입 시 내부 카운터가 0이면, release()를 호출하여 깨울 때까지 블록 합니다. 일단 깨어나면 (그리고 카운터가 0보다 크면), 카운터를 1줄이고 True를 반환합니다. release()를 호출할 때마다 정확히 하나의 스레드가 깨어납니다. 스레드가 깨어나는 순서에 의존해서는 안 됩니다.

When invoked with blocking set to False, do not block. If a call without an argument would block, return False immediately; otherwise, do the same thing as when called without arguments, and return True.

None 이외의 timeout으로 호출하면, 최대 timeout 초 동안 블록 합니다. 그 기간 획득이 완료되지 않으면, False를 반환합니다. 그렇지 않으면 True를 반환합니다.

버전 3.2에서 변경: timeout 매개 변수가 추가되었습니다.

release(n=1)

내부 카운터를 n 증가시키면서 세마포어를 해제합니다. 진입 시 0이고 다른 스레드가 다시 0보다 커지기를 기다리고 있으면, 해당 스레드를 n개 깨웁니다.

버전 3.9에서 변경: 여러 대기 스레드를 한 번에 해제하기 위해 n 매개 변수를 추가했습니다.

class threading.BoundedSemaphore(value=1)

경계 세마포어 객체를 구현하는 클래스. 경계 세마포어는 현재 값이 초깃값을 초과하지 않는지 확인합니다. 그렇다면, ValueError가 발생합니다. 대부분은 세마포어는 제한된 용량의 자원을 보호하는 데 사용됩니다. 세마포어가 너무 여러 번 해제되면 버그의 징조입니다. 지정하지 않으면, value의 기본값은 1입니다.

버전 3.3에서 변경: 팩토리 함수에서 클래스로 변경되었습니다.

Semaphore 예

세마포어는 예를 들어 데이터베이스 서버와 같이 제한된 용량의 자원을 보호하는 데 종종 사용됩니다. 자원의 크기가 고정된 상황에서는, 경계 세마포어를 사용해야 합니다. 작업자 스레드를 만들기 전에, 메인 스레드가 세마포어를 초기화합니다:

maxconnections = 5
# ...
pool_sema = BoundedSemaphore(value=maxconnections)

일단 만들어지면, 작업자 스레드는 서버에 연결해야 할 때 세마포어의 acquire 및 release 메서드를 호출합니다:

with pool_sema:
    conn = connectdb()
    try:
        # ... use connection ...
    finally:
        conn.close()

경계 세마포어를 사용하면 세마포어가 획득한 것보다 더 많이 해제되는 프로그래밍 에러가 감지되지 않을 가능성이 줄어듭니다.

Event 객체

이것은 스레드 간 통신을 위한 가장 간단한 메커니즘 중 하나입니다: 하나의 스레드는 이벤트를 알리고 다른 스레드는 이를 기다립니다.

이벤트 객체는 set() 메서드를 사용하여 참으로 설정하고 clear() 메서드를 사용하여 거짓으로 재설정 할 수 있는 내부 플래그를 관리합니다. wait() 메서드는 플래그가 참이 될 때까지 블록 합니다.

class threading.Event

이벤트 객체를 구현하는 클래스. 이벤트는 set() 메서드로 참으로 설정하고 clear() 메서드로 거짓으로 재설정 할 수 있는 플래그를 관리합니다. wait() 메서드는 플래그가 참이 될 때까지 블록 합니다. 플래그는 처음에는 거짓입니다.

버전 3.3에서 변경: 팩토리 함수에서 클래스로 변경되었습니다.

is_set()

내부 플래그가 참이면 그리고 오직 그때만 True를 반환합니다.

The method isSet is a deprecated alias for this method.

set()

내부 플래그를 참으로 설정합니다. 이것이 참이 되기를 기다리는 모든 스레드가 깨어납니다. 일단 플래그가 참이면 wait()를 호출하는 스레드는 전혀 블록 하지 않습니다.

clear()

내부 플래그를 거짓으로 재설정합니다. 이후 wait()를 호출하는 스레드는 내부 플래그를 다시 참으로 설정하기 위해 set()을 호출할 때까지 블록 합니다.

wait(timeout=None)

Block as long as the internal flag is false and the timeout, if given, has not expired. The return value represents the reason that this blocking method returned; True if returning because the internal flag is set to true, or False if a timeout is given and the internal flag did not become true within the given wait time.

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds, or fractions thereof.

버전 3.1에서 변경: 이전에는, 메서드가 항상 None을 반환했습니다.

Timer 객체

이 클래스는 특정 시간이 지난 후에만 실행되어야 하는 조치를 나타냅니다 – 타이머. Timer는 Thread의 서브 클래스이며 사용자 정의 스레드를 만드는 예제로도 기능합니다.

Timers are started, as with threads, by calling their Timer.start method. The timer can be stopped (before its action has begun) by calling the cancel() method. The interval the timer will wait before executing its action may not be exactly the same as the interval specified by the user.

예를 들면:

def hello():
    print("hello, world")

t = Timer(30.0, hello)
t.start()  # after 30 seconds, "hello, world" will be printed

class threading.Timer(interval, function, args=None, kwargs=None)

interval 초가 지난 후 args 인자와 kwargs 키워드 인자로 function을 실행하는 타이머를 만듭니다. args가 None(기본값)이면 빈 리스트가 사용됩니다. kwargs가 None(기본값)이면 빈 딕셔너리가 사용됩니다.

버전 3.3에서 변경: 팩토리 함수에서 클래스로 변경되었습니다.

cancel()

타이머를 중지하고, 타이머 조치의 실행을 취소합니다. 타이머가 아직 대기 상태에 있을 때만 작동합니다.

Barrier 객체

Added in version 3.2.

이 클래스는 서로를 기다려야 하는 고정된 수의 스레드에서 사용할 수 있는 간단한 동기화 프리미티브를 제공합니다. 각 스레드는 wait() 메서드를 호출하여 장벽(barrier)을 통과하려고 시도하고 모든 스레드가 wait() 호출을 수행할 때까지 블록 합니다. 이 시점에서, 스레드가 동시에 해제됩니다.

장벽은 같은 수의 스레드에 대해 여러 번 재사용 할 수 있습니다.

예를 들어, 다음은 클라이언트와 서버 스레드를 동기화하는 간단한 방법입니다:

b = Barrier(2, timeout=5)

def server():
    start_server()
    b.wait()
    while True:
        connection = accept_connection()
        process_server_connection(connection)

def client():
    b.wait()
    while True:
        connection = make_connection()
        process_client_connection(connection)

class threading.Barrier(parties, action=None, timeout=None)

parties 수의 스레드에 대한 장벽 객체를 만듭니다. 제공되면, action은 해제될 때 스레드 중 하나가 호출할 콜러블입니다. timeout은 wait() 메서드에 대해 지정되지 않을 때 사용될 기본 시간제한 값입니다.

wait(timeout=None)

장벽을 통과합니다. 장벽에 속한 모든 스레드가 이 함수를 호출할 때, 모두 동시에 해제됩니다. timeout이 제공되면, 클래스 생성자에 제공된 것보다 우선하여 사용됩니다.

반환 값은 0에서 parties - 1 범위의 정수이며, 스레드마다 다릅니다. 이것은 특별한 하우스키핑을 수행할 스레드를 선택하는데 사용될 수 있습니다, 예를 들어:

i = barrier.wait()
if i == 0:
    # Only one thread needs to print this
    print("passed the barrier")

생성자에 action이 제공되면, 스레드 중 하나가 해제되기 전에 호출합니다. 이 호출로 에러가 발생하면, 장벽은 망가진 상태가 됩니다.

호출 시간제한이 만료되면, 장벽은 망가진 상태가 됩니다.

스레드가 기다리는 동안 장벽이 망가지거나 재설정되면 이 메서드는 BrokenBarrierError 예외를 발생시킬 수 있습니다.

reset()

장벽을 기본의 빈 상태로 되돌립니다. 대기 중인 모든 스레드는 BrokenBarrierError 예외를 수신합니다.

상태를 알 수 없는 다른 스레드가 있을 때 이 함수를 사용하려면 외부 동기화가 필요할 수 있습니다. 장벽이 망가지면 그냥 두고 새 장벽을 만드는 것이 좋습니다.

abort()

장벽을 망가진 상태로 보냅니다. 이로 인해 wait()에 대한 활성 또는 미래의 호출이 BrokenBarrierError로 실패합니다. 예를 들어 응용 프로그램의 교착 상태를 피하고자 스레드 중 하나를 중단해야 할 때 이를 사용하십시오.

스레드 중 하나가 잘못되는 것을 막기 위해 단순히 적절한 timeout 값으로 장벽을 만드는 것이 바람직 할 수 있습니다.

parties

장벽을 통과하는 데 필요한 스레드 수.

n_waiting

현재 장벽에서 대기 중인 스레드 수.

broken

장벽이 망가진 상태이면 True인 불리언.

exception threading.BrokenBarrierError

RuntimeError의 서브 클래스인, 이 예외는 Barrier 객체가 재설정되거나 망가질 때 발생합니다.

with 문으로 록, 조건 및 세마포어 사용하기

All of the objects provided by this module that have acquire and release methods can be used as context managers for a with statement. The acquire method will be called when the block is entered, and release will be called when the block is exited. Hence, the following snippet:

with some_lock:
    # do something...

다음과 동등합니다:

some_lock.acquire()
try:
    # do something...
finally:
    some_lock.release()

현재 Lock, RLock, Condition, Semaphore 및 BoundedSemaphore 객체는 with 문 컨텍스트 관리자로 사용될 수 있습니다.

multiprocessing — Process-based parallelism

소스 코드: Lib/multiprocessing/ [https://github.com/python/cpython/tree/main/Lib/multiprocessing/]

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

소개

multiprocessing is a package that supports spawning processes using an API similar to the threading module. The multiprocessing package offers both local and remote concurrency, effectively side-stepping the Global Interpreter Lock by using subprocesses instead of threads. Due to this, the multiprocessing module allows the programmer to fully leverage multiple processors on a given machine. It runs on both POSIX and Windows.

multiprocessing 모듈은 threading 모듈에 대응 물이 없는 API도 제공합니다. 이것의 대표적인 예가 Pool 객체입니다. 이 객체는 여러 입력 값에 걸쳐 함수의 실행을 병렬 처리하고 입력 데이터를 프로세스에 분산시키는 편리한 방법을 제공합니다(데이터 병렬 처리). 다음 예제는 자식 프로세스가 해당 모듈을 성공적으로 임포트 할 수 있도록, 모듈에서 이러한 함수를 정의하는 일반적인 방법을 보여줍니다. 다음은 Pool 를 사용하는 데이터 병렬 처리의 기본 예제입니다:

from multiprocessing import Pool

def f(x):
    return x*x

if __name__ == '__main__':
    with Pool(5) as p:
        print(p.map(f, [1, 2, 3]))

표준 출력으로 다음과 같은 것을 인쇄합니다

[1, 4, 9]

더 보기

concurrent.futures.ProcessPoolExecutor offers a higher level interface to push tasks to a background process without blocking execution of the calling process. Compared to using the Pool interface directly, the concurrent.futures API more readily allows the submission of work to the underlying process pool to be separated from waiting for the results.

Process 클래스

multiprocessing에서, 프로세스는 Process 객체를 생성한 후 start() 메서드를 호출해서 스폰합니다. Process 는 threading.Thread 의 API를 따릅니다. 다중 프로세스 프로그램의 간단한 예는 다음과 같습니다

from multiprocessing import Process

def f(name):
    print('hello', name)

if __name__ == '__main__':
    p = Process(target=f, args=('bob',))
    p.start()
    p.join()

이 과정에 참여하는 개별 프로세스의 ID를 보기 위해, 이렇게 예제를 확장합니다:

from multiprocessing import Process
import os

def info(title):
    print(title)
    print('module name:', __name__)
    print('parent process:', os.getppid())
    print('process id:', os.getpid())

def f(name):
    info('function f')
    print('hello', name)

if __name__ == '__main__':
    info('main line')
    p = Process(target=f, args=('bob',))
    p.start()
    p.join()

if __name__ == '__main__' 부분이 필요한 이유에 대한 설명은 프로그래밍 지침을 보십시오.

컨텍스트 및 시작 방법

플랫폼에 따라, multiprocessing은 프로세스를 시작하는 세 가지 방법을 지원합니다. 이러한 시작 방법 은

spawn

The parent process starts a fresh Python interpreter process. The child process will only inherit those resources necessary to run the process object’s run() method. In particular, unnecessary file descriptors and handles from the parent process will not be inherited. Starting a process using this method is rather slow compared to using fork or forkserver.

Available on POSIX and Windows platforms. The default on Windows and macOS.

fork

부모 프로세스는 os.fork() 를 사용하여 파이썬 인터프리터를 포크 합니다. 자식 프로세스는, 시작될 때, 부모 프로세스와 실질적으로 같습니다. 부모의 모든 자원이 자식 프로세스에 의해 상속됩니다. 다중 스레드 프로세스를 안전하게 포크 하기 어렵다는 점에 주의하십시오.

Available on POSIX systems.

버전 3.14에서 변경: This is no longer the default start method on any platform. Code that requires fork must explicitly specify that via get_context() or set_start_method().

버전 3.12에서 변경: If Python is able to detect that your process has multiple threads, the os.fork() function that this start method calls internally will raise a DeprecationWarning. Use a different start method. See the os.fork() documentation for further explanation.

forkserver

When the program starts and selects the forkserver start method, a server process is spawned. From then on, whenever a new process is needed, the parent process connects to the server and requests that it fork a new process. The fork server process is single threaded unless system libraries or preloaded imports spawn threads as a side-effect so it is generally safe for it to use os.fork(). No unnecessary resources are inherited.

Available on POSIX platforms which support passing file descriptors over Unix pipes such as Linux. The default on those.

버전 3.14에서 변경: This became the default start method on POSIX platforms.

버전 3.4에서 변경: spawn added on all POSIX platforms, and forkserver added for some POSIX platforms. Child processes no longer inherit all of the parents inheritable handles on Windows.

버전 3.8에서 변경: On macOS, the spawn start method is now the default. The fork start method should be considered unsafe as it can lead to crashes of the subprocess as macOS system libraries may start threads. See bpo-33725 [https://bugs.python.org/issue?@action=redirect&bpo=33725].

버전 3.14에서 변경: On POSIX platforms the default start method was changed from fork to forkserver to retain the performance but avoid common multithreaded process incompatibilities. See gh-84559 [https://github.com/python/cpython/issues/84559].

On POSIX using the spawn or forkserver start methods will also start a resource tracker process which tracks the unlinked named system resources (such as named semaphores or SharedMemory objects) created by processes of the program. When all processes have exited the resource tracker unlinks any remaining tracked object. Usually there should be none, but if a process was killed by a signal there may be some “leaked” resources. (Neither leaked semaphores nor shared memory segments will be automatically unlinked until the next reboot. This is problematic for both objects because the system allows only a limited number of named semaphores, and shared memory segments occupy some space in the main memory.)

시작 방법을 선택하려면 메인 모듈의 if __name__ == '__main__' 절에서 set_start_method()를 사용하십시오. 예를 들면:

import multiprocessing as mp

def foo(q):
    q.put('hello')

if __name__ == '__main__':
    mp.set_start_method('spawn')
    q = mp.Queue()
    p = mp.Process(target=foo, args=(q,))
    p.start()
    print(q.get())
    p.join()

set_start_method() 는 프로그램에서 한 번만 사용되어야 합니다.

또는, get_context()를 사용하여 컨텍스트 객체를 얻을 수 있습니다. 컨텍스트 객체는 multiprocessing 모듈과 같은 API를 제공하므로 한 프로그램에서 여러 시작 방법을 사용할 수 있습니다.

import multiprocessing as mp

def foo(q):
    q.put('hello')

if __name__ == '__main__':
    ctx = mp.get_context('spawn')
    q = ctx.Queue()
    p = ctx.Process(target=foo, args=(q,))
    p.start()
    print(q.get())
    p.join()

한 컨텍스트와 관련된 객체는 다른 컨텍스트의 프로세스와 호환되지 않을 수 있음에 주의하십시오. 특히 fork 컨텍스트를 사용하여 생성된 록은 spawn 또는 forkserver 시작 방법을 사용하여 시작된 프로세스로 전달될 수 없습니다.

특정 시작 방법을 사용하고자 하는 라이브러리는 아마도 get_context()를 사용하여 라이브러리 사용자의 선택을 방해하지 않아야 합니다.

경고

The 'spawn' and 'forkserver' start methods generally cannot be used with “frozen” executables (i.e., binaries produced by packages like PyInstaller and cx_Freeze) on POSIX systems. The 'fork' start method may work if code does not use threads.

프로세스 간 객체 교환

multiprocessing 은 두 가지 유형의 프로세스 간 통신 채널을 지원합니다:

큐

Queue 클래스는 queue.Queue 의 클론에 가깝습니다. 예를 들면:

from multiprocessing import Process, Queue

def f(q):
    q.put([42, None, 'hello'])

if __name__ == '__main__':
    q = Queue()
    p = Process(target=f, args=(q,))
    p.start()
    print(q.get())    # prints "[42, None, 'hello']"
    p.join()

Queues are thread and process safe. Any object put into a multiprocessing queue will be serialized.

파이프

Pipe() 함수는 파이프로 연결된 한 쌍의 연결 객체를 돌려주는데 기본적으로 양방향(duplex)입니다. 예를 들면:

from multiprocessing import Process, Pipe

def f(conn):
    conn.send([42, None, 'hello'])
    conn.close()

if __name__ == '__main__':
    parent_conn, child_conn = Pipe()
    p = Process(target=f, args=(child_conn,))
    p.start()
    print(parent_conn.recv())   # prints "[42, None, 'hello']"
    p.join()

Pipe() 가 반환하는 두 개의 연결 객체는 파이프의 두 끝을 나타냅니다. 각 연결 객체에는 (다른 것도 있지만) send() 및 recv() 메서드가 있습니다. 두 프로세스 (또는 스레드)가 파이프의 같은 끝에서 동시에 읽거나 쓰려고 하면 파이프의 데이터가 손상될 수 있습니다. 물론 파이프의 다른 끝을 동시에 사용하는 프로세스로 인해 손상될 위험은 없습니다.

The send() method serializes the object and recv() re-creates the object.

프로세스 간 동기화

multiprocessing 은 threading 에 있는 모든 동기화 프리미티브의 등가물을 포함합니다. 예를 들어 한 번에 하나의 프로세스만 표준 출력으로 인쇄하도록 록을 사용할 수 있습니다:

from multiprocessing import Process, Lock

def f(l, i):
    l.acquire()
    try:
        print('hello world', i)
    finally:
        l.release()

if __name__ == '__main__':
    lock = Lock()

    for num in range(10):
        Process(target=f, args=(lock, num)).start()

록을 사용하지 않으면 다른 프로세스의 출력들이 모두 섞일 수 있습니다.

프로세스 간 상태 공유

위에서 언급했듯이, 동시성 프로그래밍을 할 때 보통 가능한 한 공유된 상태를 사용하지 않는 것이 최선입니다. 여러 프로세스를 사용할 때 특히 그렇습니다.

그러나, 정말로 공유 데이터를 사용해야 한다면 multiprocessing 이 몇 가지 방법을 제공합니다.

공유 메모리

데이터는 Value 또는 Array를 사용하여 공유 메모리 맵에 저장 될 수 있습니다. 예를 들어, 다음 코드는

from multiprocessing import Process, Value, Array

def f(n, a):
    n.value = 3.1415927
    for i in range(len(a)):
        a[i] = -a[i]

if __name__ == '__main__':
    num = Value('d', 0.0)
    arr = Array('i', range(10))

    p = Process(target=f, args=(num, arr))
    p.start()
    p.join()

    print(num.value)
    print(arr[:])

를 인쇄할 것입니다

3.1415927
[0, -1, -2, -3, -4, -5, -6, -7, -8, -9]

num 과 arr 을 만들 때 사용되는 'd' 와 'i' 인자는 array 모듈에서 사용되는 종류의 타입 코드입니다: 'd' 는 배정밀도 부동 소수점을 나타내고, 'i' 는 부호 있는 정수를 나타냅니다. 이러한 공유 객체는 프로세스 및 스레드에 안전합니다.

공유 메모리를 더 유연하게 사용하려면, 공유 메모리에 할당된 임의의 ctypes 객체 생성을 지원하는 multiprocessing.sharedctypes 모듈을 사용할 수 있습니다.

서버 프로세스

Manager() 가 반환한 관리자 객체는 파이썬 객체를 유지하고 다른 프로세스가 프락시를 사용하여 이 객체를 조작할 수 있게 하는 서버 프로세스를 제어합니다.

Manager() 가 반환한 관리자는 list, dict, Namespace, Lock, RLock, Semaphore, BoundedSemaphore, Condition, Event, Barrier, Queue, Value 그리고 Array 형을 지원합니다. 예를 들어, 다음 코드는

from multiprocessing import Process, Manager

def f(d, l):
    d[1] = '1'
    d['2'] = 2
    d[0.25] = None
    l.reverse()

if __name__ == '__main__':
    with Manager() as manager:
        d = manager.dict()
        l = manager.list(range(10))

        p = Process(target=f, args=(d, l))
        p.start()
        p.join()

        print(d)
        print(l)

를 인쇄할 것입니다

{0.25: None, 1: '1', '2': 2}
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

서버 프로세스 관리자는 임의의 객체 형을 지원하도록 만들 수 있으므로 공유 메모리 객체를 사용하는 것보다 융통성이 있습니다. 또한, 단일 관리자를 네트워크를 통해 서로 다른 컴퓨터의 프로세스에서 공유 할 수 있습니다. 그러나 공유 메모리를 사용할 때보다 느립니다.

작업자 풀 사용

Pool 클래스는 작업자 프로세스 풀을 나타냅니다. 여기에는 몇 가지 다른 방법으로 작업을 작업자 프로세스로 넘길 수 있는 메서드가 있습니다.

예를 들면:

from multiprocessing import Pool, TimeoutError
import time
import os

def f(x):
    return x*x

if __name__ == '__main__':
    # start 4 worker processes
    with Pool(processes=4) as pool:

        # print "[0, 1, 4,..., 81]"
        print(pool.map(f, range(10)))

        # print same numbers in arbitrary order
        for i in pool.imap_unordered(f, range(10)):
            print(i)

        # evaluate "f(20)" asynchronously
        res = pool.apply_async(f, (20,))      # runs in *only* one process
        print(res.get(timeout=1))             # prints "400"

        # evaluate "os.getpid()" asynchronously
        res = pool.apply_async(os.getpid, ()) # runs in *only* one process
        print(res.get(timeout=1))             # prints the PID of that process

        # launching multiple evaluations asynchronously *may* use more processes
        multiple_results = [pool.apply_async(os.getpid, ()) for i in range(4)]
        print([res.get(timeout=1) for res in multiple_results])

        # make a single worker sleep for 10 seconds
        res = pool.apply_async(time.sleep, (10,))
        try:
            print(res.get(timeout=1))
        except TimeoutError:
            print("We lacked patience and got a multiprocessing.TimeoutError")

        print("For the moment, the pool remains available for more work")

    # exiting the 'with'-block has stopped the pool
    print("Now the pool is closed and no longer available")

풀의 메서드는 풀을 만든 프로세스에서만 사용되어야 함에 유의하세요.

참고

이 패키지 내의 기능을 사용하려면 __main__ 모듈을 자식이 임포트 할 수 있어야 합니다. 이것은 프로그래밍 지침에서 다루지만, 여기에서 지적할 가치가 있습니다. 이것은 몇몇 예제, 가령 multiprocessing.pool.Pool 예제가 대화형 인터프리터에서 동작하지 않음을 의미합니다. 예를 들면:

>>> from multiprocessing import Pool
>>> p = Pool(5)
>>> def f(x):
...     return x*x
...
>>> with p:
...     p.map(f, [1,2,3])
Process PoolWorker-1:
Process PoolWorker-2:
Process PoolWorker-3:
Traceback (most recent call last):
Traceback (most recent call last):
Traceback (most recent call last):
AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>
AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>
AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>

(이것을 시도해 보면 실제로 세 개의 전체 트레이스백이 어느 정도 임의로 번갈아 출력됩니다. 그런 다음 부모 프로세스를 중지시켜야 할 수도 있습니다.)

레퍼런스

multiprocessing 패키지는 대부분 threading 모듈의 API를 복제합니다.

Process와 예외

class multiprocessing.Process(group=None, target=None, name=None, args=(), kwargs={}, *, daemon=None)

프로세스 객체는 별도의 프로세스에서 실행되는 작업을 나타냅니다. Process 클래스는 threading.Thread 의 모든 메서드와 같은 메서드를 갖습니다.

The constructor should always be called with keyword arguments. group should always be None; it exists solely for compatibility with threading.Thread. target is the callable object to be invoked by the run() method. It defaults to None, meaning nothing is called. name is the process name (see name for more details). args is the argument tuple for the target invocation. kwargs is a dictionary of keyword arguments for the target invocation. If provided, the keyword-only daemon argument sets the process daemon flag to True or False. If None (the default), this flag will be inherited from the creating process.

By default, no arguments are passed to target. The args argument, which defaults to (), can be used to specify a list or tuple of the arguments to pass to target.

서브 클래스가 생성자를 재정의하면, 프로세스에 다른 작업을 하기 전에 베이스 클래스 생성자(Process.__init__())를 호출해야 합니다.

버전 3.3에서 변경: Added the daemon parameter.

run()

프로세스의 활동을 나타내는 메서드.

서브 클래스에서 이 메서드를 재정의할 수 있습니다. 표준 run() 메서드는 객체의 생성자에 target 인자로 전달된 콜러블 객체를 호출하는데 (있다면) args 와 kwargs 인자를 각각 위치 인자와 키워드 인자로 사용합니다.

Using a list or tuple as the args argument passed to Process achieves the same effect.

Example:

>>> from multiprocessing import Process
>>> p = Process(target=print, args=[1])
>>> p.run()
1
>>> p = Process(target=print, args=(1,))
>>> p.run()
1

start()

프로세스의 활동을 시작합니다.

이것은 프로세스 객체 당 최대 한 번 호출되어야 합니다. 객체의 run() 메서드가 별도의 프로세스에서 호출되도록 합니다.

join([timeout])

선택적 인자 timeout 이 None (기본값) 인 경우, 메서드는 join() 메서드가 호출된 프로세스가 종료될 때까지 블록 됩니다. timeout 이 양수면 최대 timeout 초 동안 블록 됩니다. 이 메서드는 프로세스가 종료되거나 메서드가 시간 초과 되면 None 을 돌려줌에 주의해야 합니다. 프로세스의 exitcode 를 검사하여 종료되었는지 확인하십시오.

프로세스는 여러 번 조인할 수 있습니다.

교착 상태를 유발할 수 있으므로 프로세스는 자신을 조인할 수 없습니다. 프로세스가 시작되기 전에 프로세스에 조인하려고 하면 에러가 발생합니다.

name

프로세스의 이름. 이름은 식별 목적으로만 사용되는 문자열입니다. 다른 의미는 없습니다. 여러 프로세스에 같은 이름이 주어질 수 있습니다.

초기 이름은 생성자에 의해 설정됩니다. 명시적 이름이 생성자에 제공되지 않으면, ‘Process-N₁:N₂:…:Nk’ 형식의 이름이 만들어지는데, 각각의 Nk 는 부모의 N 번째 자식입니다.

is_alive()

프로세스가 살아있는지 아닌지를 반환합니다.

대략, 프로세스 객체는 start() 메서드가 반환하는 순간부터 자식 프로세스가 종료될 때까지 살아있습니다.

daemon

프로세스의 데몬 플래그, 논리값. start() 가 호출되기 전에 설정되어야 합니다.

초깃값은 생성 프로세스에서 상속됩니다.

프로세스가 종료할 때, 모든 데몬 자식 프로세스를 강제 종료시키려고(terminate) 시도합니다.

데몬 프로세스는 하위 프로세스를 만들 수 없음에 유의하십시오. 그렇지 않으면 부모 프로세스가 종료될 때 데몬 프로세스가 강제 종료되어, 데몬 프로세스가 자식 프로세스를 고아로 남기게 됩니다. 또한, 이들은 유닉스 데몬이나 서비스가 아닙니다, 데몬이 아닌 프로세스들이 종료되면 강제 종료되는 (그리고 조인되지 않는) 일반 프로세스입니다.

threading.Thread API 외에도 Process 객체는 다음 어트리뷰트와 메서드도 지원합니다 :

pid

프로세스 ID를 돌려줍니다. 프로세스가 스폰 되기 전에는 None 입니다.

exitcode

The child’s exit code. This will be None if the process has not yet terminated.

If the child’s run() method returned normally, the exit code will be 0. If it terminated via sys.exit() with an integer argument N, the exit code will be N.

If the child terminated due to an exception not caught within run(), the exit code will be 1. If it was terminated by signal N, the exit code will be the negative value -N.

authkey

프로세스의 인증 키 (바이트열) 입니다.

multiprocessing 이 초기화될 때, 메인 프로세스는 os.urandom() 을 사용하여 임의의 문자열을 할당받습니다.

Process 객체가 생성될 때, 부모 프로세스의 인증 키를 상속받습니다. authkey 를 다른 바이트열로 설정하여 변경할 수 있습니다.

인증 키를 참조하세요.

sentinel

프로세스가 끝나면 “준비(ready)” 될 시스템 객체의 숫자 핸들.

You can use this value if you want to wait on several events at once using multiprocessing.connection.wait(). Otherwise calling join() is simpler.

On Windows, this is an OS handle usable with the WaitForSingleObject and WaitForMultipleObjects family of API calls. On POSIX, this is a file descriptor usable with primitives from the select module.

Added in version 3.3.

terminate()

Terminate the process. On POSIX this is done using the SIGTERM signal; on Windows TerminateProcess() is used. Note that exit handlers and finally clauses, etc., will not be executed.

프로세스의 자손 프로세스들은 강제 종료되지 않을 것입니다 – 단순히 고아가 될 것입니다.

경고

연결된 프로세스가 파이프 또는 큐를 사용할 때 이 메서드를 사용하면, 파이프 또는 큐가 손상되어 다른 프로세스에서 사용할 수 없게 될 수 있습니다. 마찬가지로, 프로세스가 록이나 세마포어 등을 획득한 경우 강제 종료하면 다른 프로세스가 교착 상태가 될 수 있습니다.

kill()

Same as terminate() but using the SIGKILL signal on POSIX.

Added in version 3.7.

close()

Process 객체를 닫아, 그것과 관련된 모든 자원을 해제합니다. 하부 프로세스가 여전히 실행 중이면 ValueError 가 발생합니다. 일단 close() 가 성공적으로 반환되면, Process 객체의 다른 대부분의 메서드와 어트리뷰트는 ValueError 를 발생시킵니다.

Added in version 3.7.

start(), join(), is_alive(), terminate() 및 exitcode 메서드는 프로세스 객체를 생성한 프로세스에 의해서만 호출되어야 합니다.

Process 의 몇몇 메서드를 사용하는 예제:

>>> import multiprocessing, time, signal
>>> mp_context = multiprocessing.get_context('spawn')
>>> p = mp_context.Process(target=time.sleep, args=(1000,))
>>> print(p, p.is_alive())
<...Process ... initial> False
>>> p.start()
>>> print(p, p.is_alive())
<...Process ... started> True
>>> p.terminate()
>>> time.sleep(0.1)
>>> print(p, p.is_alive())
<...Process ... stopped exitcode=-SIGTERM> False
>>> p.exitcode == -signal.SIGTERM
True

exception multiprocessing.ProcessError

모든 multiprocessing 예외의 베이스 클래스입니다.

exception multiprocessing.BufferTooShort

Exception raised by Connection.recv_bytes_into() when the supplied buffer object is too small for the message read.

e 가 BufferTooShort 의 인스턴스라면, e.args[0] 는 메시지를 바이트열로 줍니다.

exception multiprocessing.AuthenticationError

인증 에러가 일어날 때 발생합니다.

exception multiprocessing.TimeoutError

시간제한이 초과하였을 때 시간제한을 건 메서드에 의해 발생합니다.

파이프와 큐

여러 프로세스를 사용할 때, 일반적으로 프로세스 간 통신을 위해 메시지 전달을 사용하고 록과 같은 동기화 프리미티브 사용을 피합니다.

메시지를 전달하기 위해 Pipe() (두 프로세스 간의 연결) 또는 큐(여러 생산자와 소비자를 허용합니다)를 사용할 수 있습니다.

Queue, SimpleQueue 그리고 JoinableQueue 형은, 표준 라이브러리의 queue.Queue 클래스에 따라 모델링 된, 다중 생산자, 다중 소비자 FIFO 큐입니다. 이것들은 파이썬 2.5의 queue.Queue 클래스에서 도입된 task_done()과 join() 메서드가 Queue 에 없다는 점에서 다릅니다.

JoinableQueue를 사용하면, 큐에서 제거된 작업마다 JoinableQueue.task_done()을 호출해야 합니다. 그렇지 않으면 완료되지 않은 작업의 수를 세는 데 사용되는 세마포어가 결국 오버플로 되어 예외를 일으킵니다.

One difference from other Python queue implementations, is that multiprocessing queues serializes all objects that are put into them using pickle. The object return by the get method is a re-created object that does not share memory with the original object.

관리자 객체를 사용하여 공유 큐를 생성할 수도 있습니다 – 관리자를 보세요.

참고

multiprocessing 은 제한 시간 초과 신호를 보내기 위해 보통 queue.Empty 와 queue.Full 예외를 사용합니다. multiprocessing 이름 공간에는 없으므로 queue에서 임포트 해야 합니다.

참고

객체를 큐에 넣으면, 객체는 피클 되고 배경 스레드가 나중에 피클 된 데이터를 하부 파이프로 플러시 합니다. 이것은 다소 의외의 결과로 이어지지만, 실제적인 어려움을 일으키지는 않아야 합니다 – 이것이 여러분을 정말로 신경 쓰이게 한다면, 대신 관리자 로 만든 큐를 사용할 수 있습니다.

빈 큐에 객체를 넣은 후에, empty() 메서드가 False를 반환하고 get_nowait()가 queue.Empty 를 일으키지 않고 반환할 수 있기 전까지 극히 작은 지연이 있을 수 있습니다.

여러 프로세스가 객체를 큐에 넣는 경우, 반대편에서 객체가 다른 순서로 수신될 수 있습니다. 그러나, 같은 프로세스에 의해 큐에 들어간 객체들은 항상 상대적인 순서가 유지됩니다.

경고

Queue를 사용하려고 하는 동안 Process.terminate() 또는 os.kill() 을 사용하여 프로세스를 죽이면, 큐의 데이터가 손상될 수 있습니다. 이로 인해 나중에 다른 프로세스가 큐를 사용하려고 할 때 예외가 발생할 수 있습니다.

경고

위에서 언급했듯이, 자식 프로세스가 항목을 큐에 넣었을 때 (그리고 JoinableQueue.cancel_join_thread 를 사용하지 않았다면), 버퍼링 된 모든 항목이 파이프로 플러시 될 때까지 해당 프로세스가 종료되지 않습니다.

이것은, 여러분이 그 자식 프로세스를 조인하려고 하면, 큐에 넣은 모든 항목을 소진하지 않는 한 교착 상태가 발생할 수 있다는 뜻입니다. 마찬가지로, 그 자식 프로세스가 데몬이 아니면 부모 프로세스가 종료 시점에 데몬이 아닌 모든 자식을 조인하려고 할 때 정지될 수 있습니다.

관리자를 사용하여 생성된 큐에는 이 문제가 없습니다. 프로그래밍 지침을 참조하세요.

프로세스 간 통신을 위해 큐를 사용하는 예는 예제을 참조하십시오.

multiprocessing.Pipe([duplex])

파이프의 끝을 나타내는 Connection 객체 쌍 (conn1, conn2) 를 반환합니다.

duplex 가 True (기본값) 면 파이프는 양방향입니다. duplex 가 False 인 경우 파이프는 단방향입니다: conn1 은 메시지를 받는 데에만 사용할 수 있고, conn2 는 메시지를 보낼 때만 사용할 수 있습니다.

The send() method serializes the object using pickle and the recv() re-creates the object.

class multiprocessing.Queue([maxsize])

파이프와 몇 개의 록/세마포어를 사용하여 구현된 프로세스 공유 큐를 반환합니다. 프로세스가 처음으로 항목을 큐에 넣으면 버퍼에서 파이프로 객체를 전송하는 피더 스레드가 시작됩니다.

제한 시간 초과를 알리기 위해 표준 라이브러리의 queue 모듈에서 정의되는 queue.Empty 와 queue.Full 예외를 일으킵니다.

Queue 는 task_done()과 join() 을 제외한 queue.Queue 의 모든 메서드를 구현합니다.

qsize()

큐의 대략의 크기를 돌려줍니다. 다중 스레딩/다중 프로세싱 특성을 타기 때문에 이 숫자는 신뢰할 수 없습니다.

Note that this may raise NotImplementedError on platforms like macOS where sem_getvalue() is not implemented.

empty()

큐가 비어 있다면 True 를, 그렇지 않으면 False 를 반환합니다. 다중 스레딩/다중 프로세싱 특성을 타기 때문에 신뢰할 수 없습니다.

May raise an OSError on closed queues. (not guaranteed)

full()

큐가 가득 차면 True 를, 그렇지 않으면 False 를 반환합니다. 다중 스레딩/다중 프로세싱 특성을 타기 때문에 신뢰할 수 없습니다.

put(obj[, block[, timeout]])

obj를 큐에 넣습니다. 선택적 인자 block 이 True (기본값)이고 timeout 이 None (기본값) 이면, 빈 슬롯이 생길 때까지 필요한 경우 블록합니다. timeout 이 양수인 경우, 최대 timeout 초만큼 블록하고 그 시간 내에 사용 가능 슬롯이 생기지 않으면 queue.Full 예외를 발생시킵니다. 그렇지 않으면 (block 이 False) 빈 슬롯을 즉시 사용할 수 있으면 큐에 항목을 넣고, 그렇지 않으면 queue.Full 예외를 발생시킵니다 (이 경우 timeout 은 무시됩니다).

버전 3.8에서 변경: 큐가 닫혔으면, AssertionError 대신 ValueError가 발생합니다.

put_nowait(obj)

put(obj, False) 와 같습니다.

get([block[, timeout]])

큐에서 항목을 제거하고 반환합니다. 선택적 인자 block 이 True (기본값)이고 timeout 이 None (기본값) 이면, 항목이 들어올 때까지 필요한 경우 블록합니다. timeout 이 양수인 경우, 최대 timeout 초만큼 블록하고 그 시간 내에 항목이 들어오지 않으면 queue.Empty 예외를 발생시킵니다. 그렇지 않으면 (block이 False) 즉시 사용할 수 있는 항목이 있으면 반환하고, 그렇지 않으면 queue.Empty 예외를 발생시킵니다 (이 경우 timeout 은 무시됩니다).

버전 3.8에서 변경: 큐가 닫혔으면, OSError 대신 ValueError가 발생합니다.

get_nowait()

get(False) 와 같습니다.

multiprocessing.Queue 에는 queue.Queue 에서 찾을 수 없는 몇 가지 추가 메서드가 있습니다. 일반적으로 이러한 메서드는 대부분 코드에서 필요하지 않습니다:

close()

현재 프로세스가 이 큐에 더는 데이터를 넣지 않을 것을 나타냅니다. 버퍼에 저장된 모든 데이터를 파이프로 플러시 하면 배경 스레드가 종료됩니다. 큐가 가비지 수집될 때 자동으로 호출됩니다.

join_thread()

배경 스레드에 조인합니다. close() 가 호출된 후에만 사용할 수 있습니다. 배경 스레드가 종료될 때까지 블록해서 버퍼의 모든 데이터가 파이프로 플러시 되었음을 보증합니다.

기본적으로 프로세스가 큐를 만든 주체가 아니면 종료할 때 큐의 배경 스레드를 조인하려고 합니다. 프로세스는 cancel_join_thread()를 호출하여 join_thread() 가 아무것도 하지 않게 할 수 있습니다.

cancel_join_thread()

join_thread() 의 블록을 방지합니다. 특히, 프로세스가 종료할 때 배경 스레드를 자동으로 조인하는 것을 막습니다 – join_thread()를 보십시오.

A better name for this method might be allow_exit_without_flush(). It is likely to cause enqueued data to be lost, and you almost certainly will not need to use it. It is really only there if you need the current process to exit immediately without waiting to flush enqueued data to the underlying pipe, and you don’t care about lost data.

참고

이 클래스의 기능은 호스트 운영 체제의 작동하는 공유 세마포어 구현을 요구합니다. 그런 것이 없으면, 클래스의 기능이 비활성화되고, Queue 의 인스턴스를 만들려고 하면 ImportError 를 일으킵니다. 자세한 내용은 bpo-3770 [https://bugs.python.org/issue?@action=redirect&bpo=3770]을 참조하십시오. 아래에 나열된 특수 큐 형들도 마찬가지입니다.

class multiprocessing.SimpleQueue

이것은 단순화된 Queue 형으로, 록이 걸린 Pipe 에 매우 가깝습니다.

close()

큐를 닫습니다: 내부 자원을 해제합니다.

큐를 닫은 후에는 더는 사용해서는 안 됩니다. 예를 들어, get(), put() 및 empty() 메서드가 더는 호출되지 않아야 합니다.

Added in version 3.9.

empty()

큐가 비어 있다면 True 를, 그렇지 않으면 False 를 반환합니다.

Always raises an OSError if the SimpleQueue is closed.

get()

큐에서 항목을 제거하고 반환합니다.

put(item)

item 을 큐에 넣습니다.

class multiprocessing.JoinableQueue([maxsize])

Queue 서브 클래스 JoinableQueue 는 추가로 task_done()과 join() 메서드를 가진 큐입니다.

task_done()

앞서 큐에 넣은 작업이 완료되었음을 나타냅니다. 큐 소비자가 사용합니다. 작업을 가져오는데 사용된 각 get() 마다, 뒤따르는 task_done() 호출은 작업에 대한 처리가 완료되었음을 큐에 알립니다.

만약 join() 이 현재 블록하고 있다면, 모든 항목이 처리될 때 재개될 것입니다 (put() 으로 큐에 넣은 모든 항목에 대해 task_done() 호출을 수신했다는 뜻입니다).

큐에 있는 항목보다 많이 호출되면 ValueError 를 발생시킵니다.

join()

큐의 모든 항목을 가져가서 처리할 때까지 블록합니다.

항목이 큐에 추가될 때마다 완료되지 않은 작업의 수는 올라갑니다. 소비자가 그 항목을 꺼냈고 그에 대한 모든 작업을 완료했음을 알리기 위해 task_done()을 호출할 때마다 숫자는 줄어듭니다. 완료되지 않은 작업의 수가 0으로 떨어지면 join() 이 블록으로부터 풀려납니다.

잡동사니

multiprocessing.active_children()

현재 프로세스의 모든 살아있는 자식 리스트를 반환합니다.

이것을 호출하면 이미 완료된 프로세스에 “조인” 하는 부작용이 있습니다.

multiprocessing.cpu_count()

시스템의 CPU 수를 반환합니다.

This number is not equivalent to the number of CPUs the current process can use. The number of usable CPUs can be obtained with os.process_cpu_count() (or len(os.sched_getaffinity(0))).

When the number of CPUs cannot be determined a NotImplementedError is raised.

더 보기

os.cpu_count() os.process_cpu_count()

버전 3.13에서 변경: The return value can also be overridden using the -X cpu_count flag or PYTHON_CPU_COUNT as this is merely a wrapper around the os cpu count APIs.

multiprocessing.current_process()

현재 프로세스에 해당하는 Process 객체를 반환합니다.

threading.current_thread()와 유사한 기능을 제공합니다.

multiprocessing.parent_process()

current_process()의 부모 프로세스에 해당하는 Process 객체를 반환합니다. 메인 프로세스에서, parent_process는 None입니다.

Added in version 3.8.

multiprocessing.freeze_support()

multiprocessing을 사용하는 프로그램이 고정되어(frozen) 윈도우 실행 파일을 생성할 때를 위한 지원을 추가합니다. (py2exe, PyInstaller 및 cx_Freeze 에서 테스트 되었습니다.)

메인 모듈의 if __name__ == '__main__' 줄 바로 뒤에서 이 함수를 호출해야 합니다. 예를 들면:

from multiprocessing import Process, freeze_support

def f():
    print('hello world!')

if __name__ == '__main__':
    freeze_support()
    Process(target=f).start()

freeze_support() 줄이 생략된 경우 고정된 실행 파일을 실행하려고 하면 RuntimeError 가 발생합니다.

freeze_support() 호출은 윈도우가 아닌 다른 운영 체제에서 실행될 때는 아무런 영향을 미치지 않습니다. 또한, 모듈이 윈도우상의 파이썬 인터프리터에 의해 정상적으로 실행되는 경우 (프로그램이 고정되지 않은 경우)에도 freeze_support() 는 아무 효과가 없습니다.

multiprocessing.get_all_start_methods()

Returns a list of the supported start methods, the first of which is the default. The possible start methods are 'fork', 'spawn' and 'forkserver'. Not all platforms support all methods. See 컨텍스트 및 시작 방법.

Added in version 3.4.

multiprocessing.get_context(method=None)

multiprocessing 모듈과 같은 어트리뷰트를 가진 컨텍스트 객체를 반환합니다.

If method is None then the default context is returned. Otherwise method should be 'fork', 'spawn', 'forkserver'. ValueError is raised if the specified start method is not available. See 컨텍스트 및 시작 방법.

Added in version 3.4.

multiprocessing.get_start_method(allow_none=False)

프로세스를 기동하기 위해서 사용되는 시작 방법의 이름을 돌려줍니다.

시작 방법이 고정되지 않았고 allow_none 이 거짓이면, 시작 방법이 기본값으로 고정되고 이름이 반환됩니다. 시작 방법이 고정되지 않았고 allow_none이 참이면, None 이 반환됩니다.

The return value can be 'fork', 'spawn', 'forkserver' or None. See 컨텍스트 및 시작 방법.

Added in version 3.4.

버전 3.8에서 변경: macOS에서, spawn 시작 방법이 이제 기본값입니다. fork 시작 방법은 서브 프로세스의 충돌로 이어질 수 있기 때문에, 안전하지 않은 것으로 간주해야 합니다. bpo-33725 [https://bugs.python.org/issue?@action=redirect&bpo=33725]를 참조하십시오.

multiprocessing.set_executable(executable)

Set the path of the Python interpreter to use when starting a child process. (By default sys.executable is used). Embedders will probably need to do some thing like

set_executable(os.path.join(sys.exec_prefix, 'pythonw.exe'))

자식 프로세스를 만들기 전에 해야 합니다.

버전 3.4에서 변경: Now supported on POSIX when the 'spawn' start method is used.

버전 3.11에서 변경: Accepts a path-like object.

multiprocessing.set_forkserver_preload(module_names)

Set a list of module names for the forkserver main process to attempt to import so that their already imported state is inherited by forked processes. Any ImportError when doing so is silently ignored. This can be used as a performance enhancement to avoid repeated work in every process.

For this to work, it must be called before the forkserver process has been launched (before creating a Pool or starting a Process).

Only meaningful when using the 'forkserver' start method. See 컨텍스트 및 시작 방법.

Added in version 3.4.

multiprocessing.set_start_method(method, force=False)

Set the method which should be used to start child processes. The method argument can be 'fork', 'spawn' or 'forkserver'. Raises RuntimeError if the start method has already been set and force is not True. If method is None and force is True then the start method is set to None. If method is None and force is False then the context is set to the default context.

이것은 한 번만 호출해야 하며, 메인 모듈의 if __name__ == '__main__' 절 내에서 보호되어야 합니다.

See 컨텍스트 및 시작 방법.

Added in version 3.4.

참고

multiprocessing 에는 threading.active_count(), threading.enumerate(), threading.settrace(), threading.setprofile(), threading.Timer 또는 threading.local 의 대응 물이 없습니다.

Connection 객체

연결 객체를 사용하면 피클 가능한 객체나 문자열을 보내고 받을 수 있습니다. 메시지 지향 연결된 소켓으로 생각할 수 있습니다.

연결 객체는 보통 Pipe 를 사용해서 만들어집니다 – 리스너와 클라이언트 도 참고하세요.

class multiprocessing.connection.Connection

send(obj)

연결의 반대편 끝에서 recv()를 사용하여 읽을 객체를 보냅니다.

객체는 피클 가능해야 합니다. 매우 큰 피클(약 32 MiB+, OS에 따라 다릅니다)은 ValueError 예외를 발생시킬 수 있습니다.

recv()

연결의 반대편 끝에서 send()로 보낸 객체를 반환합니다. 뭔가 수신할 때까지 블록합니다. 수신할 내용이 없고 반대편 끝이 닫혔으면 EOFError를 발생시킵니다.

fileno()

연결이 사용하는 파일 기술자나 핸들을 돌려줍니다.

close()

연결을 닫습니다.

연결이 가비지 수집될 때 자동으로 호출됩니다.

poll([timeout])

읽어 들일 데이터가 있는지를 돌려줍니다.

timeout 을 지정하지 않으면 즉시 반환됩니다. timeout 이 숫자면 블록할 최대 시간(초)을 지정합니다. timeout 이 None 이면 시간제한이 없습니다.

여러 개의 연결 객체를 multiprocessing.connection.wait() 을 사용하여 한 번에 폴링 할 수 있습니다.

send_bytes(buffer[, offset[, size]])

바이트열류 객체 의 바이트 데이터를 하나의 완전한 메시지로 보냅니다.

offset 이 주어지면 buffer 의 해당 위치부터 데이터를 읽습니다. size 가 주어지면 그만큼의 바이트를 버퍼에서 읽습니다. 매우 큰 버퍼(약 32 MiB+, OS에 따라 다릅니다)는 ValueError 예외를 발생시킬 수 있습니다

recv_bytes([maxlength])

접속의 반대편 끝에서 송신된 바이트 데이터의 완전한 메시지를 문자열로 돌려줍니다. 뭔가 수신할 때까지 블록합니다. 수신할 내용이 없고 반대편 끝이 닫혔으면 EOFError를 발생시킵니다.

maxlength 가 지정되고 메시지가 maxlength 보다 길면 OSError 가 발생하고 연결은 더는 읽을 수 없게 됩니다.

버전 3.3에서 변경: 이 함수는 IOError 를 발생시켜왔는데, 이제는 OSError 의 별칭입니다.

recv_bytes_into(buffer[, offset])

연결의 반대편 끝에서 보낸 바이트 데이터의 전체 메시지를 buffer 로 읽어 들이고, 메시지의 바이트 수를 반환합니다. 뭔가 수신할 때까지 블록합니다. 수신할 내용이 없고 반대편 끝이 닫혔으면 EOFError를 발생시킵니다.

buffer 는 쓰기 가능한 바이트열류 객체 여야 합니다. offset 이 지정되면, 버퍼의 그 위치로부터 메시지를 씁니다. offset은 buffer 길이보다 작은 음수가 아닌 정수여야 합니다 (바이트 단위).

버퍼가 너무 작으면 BufferTooShort 예외가 발생하고, 완전한 메시지는 e.args[0] 으로 제공되는데, 여기서 e 는 예외 인스턴스입니다.

버전 3.3에서 변경: 이제 연결 객체 자체를 Connection.send() 와 Connection.recv() 를 사용하여 프로세스 간에 전송할 수 있습니다.

Connection objects also now support the context management protocol – see 컨텍스트 관리자 형. __enter__() returns the connection object, and __exit__() calls close().

예를 들어:

>>> from multiprocessing import Pipe
>>> a, b = Pipe()
>>> a.send([1, 'hello', None])
>>> b.recv()
[1, 'hello', None]
>>> b.send_bytes(b'thank you')
>>> a.recv_bytes()
b'thank you'
>>> import array
>>> arr1 = array.array('i', range(5))
>>> arr2 = array.array('i', [0] * 10)
>>> a.send_bytes(arr1)
>>> count = b.recv_bytes_into(arr2)
>>> assert count == len(arr1) * arr1.itemsize
>>> arr2
array('i', [0, 1, 2, 3, 4, 0, 0, 0, 0, 0])

경고

Connection.recv() 메서드는 수신한 데이터를 자동으로 언 피클 합니다. 메시지를 보낸 프로세스를 신뢰할 수 없다면 보안상 위험 할 수 있습니다.

따라서, 연결 객체가 Pipe()를 사용하여 생성되지 않았다면, 일종의 인증을 수행한 후에만 recv() 및 send() 메서드를 사용해야 합니다. 인증 키를 참조하세요.

경고

프로세스가 파이프에 읽거나 쓰려고 할 때 죽으면, 파이프의 데이터가 손상될 가능성이 있습니다. 메시지 경계가 어디에 있는지 확신할 수 없는 상태가 될 가능성이 있기 때문입니다.

동기화 프리미티브

일반적으로 다중 프로세스 프로그램에서는 동기화 프리미티브가 다중 스레드 프로그램에서만큼 필요하지는 않습니다. threading 모듈에 대한 설명서를 참조하십시오.

관리자 객체를 사용하여 동기화 프리미티브를 생성할 수도 있습니다 – 관리자를 참조하세요.

class multiprocessing.Barrier(parties[, action[, timeout]])

배리어(barrier) 객체: threading.Barrier 의 복제본.

Added in version 3.3.

class multiprocessing.BoundedSemaphore([value])

제한된 세마포어 객체: threading.BoundedSemaphore 과 유사한 대응 물.

대응 물과 한 가지 차이가 있습니다: acquire 메서드의 첫 번째 인자에 block 이라는 이름을 사용해서 Lock.acquire() 와의 일관성을 유지합니다.

참고

On macOS, this is indistinguishable from Semaphore because sem_getvalue() is not implemented on that platform.

class multiprocessing.Condition([lock])

조건 변수: threading.Condition 의 별칭.

lock 을 지정할 때는 multiprocessing 의 Lock 이나 RLock 객체여야 합니다.

버전 3.3에서 변경: wait_for() 메서드가 추가되었습니다.

class multiprocessing.Event

threading.Event 의 복제본.

class multiprocessing.Lock

비 재귀적 록 객체: threading.Lock 과 유사한 대응 물. 일단 프로세스 또는 스레드가 록을 획득하면, 프로세스 또는 스레드에서 록을 획득하려는 후속 시도는 록이 해제될 때까지 블록 됩니다; 모든 프로세스 또는 스레드가 이를 해제할 수 있습니다. 스레드에 적용되는 threading.Lock 의 개념과 동작은, 명시된 경우를 제외하고, multiprocessing.Lock 를 통해 프로세스나 스레드에 그대로 적용됩니다.

Lock 은 실제로 기본 컨텍스트로 초기화된 multiprocessing.synchronize.Lock 의 인스턴스를 반환하는 팩토리 함수입니다.

Lock 은 컨텍스트 관리자 프로토콜을 지원하므로 with 문에서 사용될 수 있습니다.

acquire(block=True, timeout=None)

블록하거나 블록하지 않는 방식으로 록을 획득합니다.

block 인자가 True (기본값) 로 설정되면, 메서드 호출은 록이 해제 상태가 될 때까지 블록 한 다음, 잠금 상태로 만들고 True 를 반환합니다. 이 첫 번째 인자의 이름은 threading.Lock.acquire() 와 다르다는 것에 유의하세요.

block 인자가 False 로 설정되면, 메서드 호출은 블록 되지 않습니다. 록이 현재 잠금 상태면 False 를 반환합니다. 그렇지 않으면 록을 잠금 상태로 설정하고 True 를 반환합니다.

timeout 에 대해 양의 부동 소수점 값을 사용하여 호출하는 경우, 록을 얻을 수 없는 한 최대 timeout 으로 지정된 시간(초) 동안 블록합니다. timeout 을 음수 값으로 호출하는 것은 timeout 에 0을 주는 것과 같습니다. timeout 값이 None (기본값) 인 호출은 제한 시간을 무한대로 설정합니다. timeout 에 대한 음수와 None 값의 처리는 threading.Lock.acquire() 에서 구현된 동작과 다르다는 것에 주의하십시오. timeout 인자는 block 인자가 False 로 설정되면 실제적인 의미는 없고 무시됩니다. 록이 획득되면 True 를 돌려주고, 제한 시간 초과가 발생하면 False 를 돌려줍니다.

release()

록을 해제합니다. 이것은 원래 록을 획득한 프로세스나 스레드뿐만 아니라 모든 프로세스나 스레드에서 호출 할 수 있습니다.

동작은 threading.Lock.release() 와 같지만, 해제된 록에서 호출될 때 ValueError 가 발생한다는 점만 다릅니다.

class multiprocessing.RLock

재귀적 록 객체: threading.RLock 과 유사한 대응 물. 재귀적 록은 획득한 프로세스 또는 스레드에 의해 해제되어야 합니다. 일단 프로세스나 스레드가 재귀적 록을 획득하면, 같은 프로세스나 스레드가 블록 없이 다시 획득할 수 있습니다; 해당 프로세스나 스레드는 획득할 때마다 한 번 해제해야 합니다.

RLock 은 실제로 기본 컨텍스트로 초기화된 multiprocessing.synchronize.RLock 의 인스턴스를 반환하는 팩토리 함수입니다.

RLock 은 컨텍스트 관리자 프로토콜을 지원하므로 with 문에서 사용될 수 있습니다.

acquire(block=True, timeout=None)

블록하거나 블록하지 않는 방식으로 록을 획득합니다.

block 인자를 True 로 설정해서 호출하면, 록이 현재 프로세스나 스레드가 이미 획득한 상태가 아니면 록이 (어떤 프로세스나 스레드도 획득하지 않은) 록 해제 상태가 될 때까지 블록합니다. 이후에 현재 프로세스나 스레드가 (소유권이 아직 없는 경우) 록 소유권을 얻게 되며 록 내 재귀 수준이 1 증가하고 True 를 반환합니다. 이 첫 번째 인자의 동작에는, 인자의 이름부터 시작해서 threading.RLock.acquire() 구현과 비교되는 몇 가지 차이점이 있습니다.

block 인자를 False 로 설정해서 호출하면 블록하지 않습니다. 록이 이미 다른 프로세스나 스레드에 의해 획득되었으면 (그래서 소유하고 있으면), 현재 프로세스나 스레드는 소유권을 갖지 않으며 록 내 재귀 수준은 변경되지 않고 False 를 반환합니다. 록이 해제 상태에 있으면, 현재 프로세스 또는 스레드가 소유권을 가져오며 재귀 수준이 증가하고 True 를 반환합니다.

timeout 인자의 사용법과 동작은 Lock.acquire() 와 같습니다. timeout 의 이러한 동작 중 일부는 threading.RLock.acquire() 에서 구현된 동작과 다르다는 것에 주의하십시오.

release()

재귀 수준을 감소시키면서 록을 해제합니다. 감소 후에 재귀 수준이 0이면, 록을 해제 상태(어떤 프로세스나 스레드에도 소유되지 않음)로 재설정하고, 다른 프로세스나 스레드가 록이 해제될 때까지 기다리며 블록하고 있는 경우 해당 프로세스나 스레드 중 정확히 하나가 계속 진행하도록 허용합니다. 감소 후에 재귀 수준이 여전히 0이 아닌 경우, 록은 획득된 상태로 남고 호출한 프로세스나 스레드에 의해 소유됩니다.

호출한 프로세스나 스레드가 록을 소유하고 있을 때만 이 메서드를 호출하십시오. 이 메서드가 소유자가 아닌 프로세스나 스레드에 의해 호출되거나, 록이 해제 (소유되지 않은) 상태면 AssertionError 가 발생합니다. 이 상황에서 발생하는 예외 형은 threading.RLock.release() 에서 구현된 동작과 다릅니다.

class multiprocessing.Semaphore([value])

세마포어 객체: threading.Semaphore 와 유사한 대응 물.

대응 물과 한 가지 차이가 있습니다: acquire 메서드의 첫 번째 인자에 block 이라는 이름을 사용해서 Lock.acquire() 와의 일관성을 유지합니다.

참고

On macOS, sem_timedwait is unsupported, so calling acquire() with a timeout will emulate that function’s behavior using a sleeping loop.

참고

이 패키지의 기능 중 일부는 호스트 운영 체제의 작동하는 공유 세마포어 구현을 요구합니다. 그런 것이 없으면, multiprocessing.synchronize 모듈이 비활성화되고, 임포트하려고 하면 ImportError 를 일으킵니다. 자세한 내용은 bpo-3770 [https://bugs.python.org/issue?@action=redirect&bpo=3770]을 참조하십시오.

공유 ctypes 객체

자식 프로세스가 상속할 수 있는 공유 메모리를 사용하여 공유 객체를 만들 수 있습니다.

multiprocessing.Value(typecode_or_type, *args, lock=True)

공유 메모리에 할당된 ctypes 객체를 반환합니다. 기본적으로 반환 값은, 사실 객체에 대한 동기화 된 래퍼입니다. 객체 자체는 Value 의 value 어트리뷰트를 통해 접근 할 수 있습니다.

typecode_or_type 은 반환된 객체의 형을 결정합니다: ctypes 형이거나 array 모듈에 의해 사용되는 종류의 한 문자 typecode입니다. *args 는 형의 생성자로 전달됩니다.

lock 이 True (기본값) 면 값에 대한 액세스를 동기화하기 위해 새 재귀적 록 객체가 생성됩니다. lock 이 Lock 또는 RLock 객체인 경우, 이 값이 값에 대한 액세스를 동기화하는 데 사용됩니다. lock 이 False 면, 반환된 객체에 대한 액세스는 록에 의해 자동으로 보호되지 않으므로 “프로세스 안전” 하지 않습니다.

읽기와 쓰기를 포함하는 += 와 같은 연산은 원자 적(atomic)이지 않습니다. 따라서, 예를 들어, 공유 값을 원자 적으로 증가시키려면, 다음과 같이 하는 것으로는 충분하지 않습니다:

counter.value += 1

연관된 록이 재귀적이라고 가정하면 (기본적으로 그렇습니다), 대신 다음과 같이 할 수 있습니다

with counter.get_lock():
    counter.value += 1

lock 은 키워드 전용 인자입니다.

multiprocessing.Array(typecode_or_type, size_or_initializer, *, lock=True)

공유 메모리에서 할당된 ctypes 배열을 반환합니다. 기본적으로 반환 값은, 사실 배열에 대한 동기화 된 래퍼입니다.

typecode_or_type 은 반환된 배열의 요소의 형을 결정합니다: ctypes 형이거나 array 모듈에 의해 사용되는 종류의 한 문자 typecode입니다. size_or_initializer 가 정수면, 배열의 길이를 결정하고 배열은 0으로 초기화됩니다. 그렇지 않으면, size_or_initializer 는 배열을 초기화하는 데 사용되는 시퀀스고, 길이는 배열의 길이를 결정합니다.

lock 이 True (기본값) 면 값에 대한 액세스를 동기화하기 위해 새 록 객체가 생성됩니다. lock 이 Lock 또는 RLock 객체인 경우, 이 값이 값에 대한 액세스를 동기화하는 데 사용됩니다. lock 이 False 면, 반환된 객체에 대한 액세스는 록에 의해 자동으로 보호되지 않으므로 “프로세스 안전” 하지 않습니다.

lock 은 키워드 전용 인자입니다.

ctypes.c_char 의 배열은 value 와 raw 어트리뷰트를 가지고 있습니다. 이 어트리뷰트를 사용하여 문자열을 저장하고 꺼낼 수 있습니다.

multiprocessing.sharedctypes 모듈

multiprocessing.sharedctypes 모듈은 자식 프로세스에 의해 상속될 수 있는 공유 메모리에 ctypes 객체를 할당하는 기능을 제공합니다.

참고

공유 메모리에 포인터를 저장할 수는 있지만, 특정 프로세스의 주소 공간에 있는 위치를 참조하게 됩니다. 그러나 포인터는 두 번째 프로세스의 컨텍스트에서는 유효하지 않을 가능성이 커서, 두 번째 프로세스에서 포인터를 역 참조하려고 하면 충돌이 일어날 수 있습니다.

multiprocessing.sharedctypes.RawArray(typecode_or_type, size_or_initializer)

공유 메모리에 할당된 ctypes 배열을 반환합니다.

typecode_or_type 은 반환된 배열의 요소의 형을 결정합니다: ctypes 형이거나 array 모듈에 의해 사용되는 종류의 한 문자 typecode입니다. size_or_initializer 가 정수면, 배열의 길이를 결정하고 배열은 0으로 초기화됩니다. 그렇지 않으면, size_or_initializer 는 배열을 초기화하는 데 사용되는 시퀀스고, 길이는 배열의 길이를 결정합니다.

요소를 쓰고 읽는 것은 잠재적으로 원자 적이지 않습니다 – 액세스가 록을 사용하여 자동으로 동기화되기 원하면 Array()를 대신 사용하세요.

multiprocessing.sharedctypes.RawValue(typecode_or_type, *args)

공유 메모리에 할당된 ctypes 객체를 반환합니다.

typecode_or_type 은 반환된 객체의 형을 결정합니다: ctypes 형이거나 array 모듈에 의해 사용되는 종류의 한 문자 typecode입니다. *args 는 형의 생성자로 전달됩니다.

값을 쓰고 읽는 것은 잠재적으로 원자 적이지 않습니다 – 액세스가 록을 사용하여 자동으로 동기화되기 원하면 Value()를 대신 사용하세요.

ctypes.c_char 의 배열은 value 와 raw 어트리뷰트를 가지고 있습니다. 이 어트리뷰트를 사용하여 문자열을 저장하고 꺼낼 수 있습니다 – ctypes 설명서를 보십시오.

multiprocessing.sharedctypes.Array(typecode_or_type, size_or_initializer, *, lock=True)

lock 값에 따라, 날 ctypes 배열 대신 프로세스 안전한 동기화 래퍼가 반환될 수 있다는 것을 제외하고는 RawArray() 와 같습니다.

lock 이 True (기본값) 면 값에 대한 액세스를 동기화하기 위해 새 록 객체가 생성됩니다. lock 이 Lock 또는 RLock 객체인 경우, 이 값이 값에 대한 액세스를 동기화하는 데 사용됩니다. lock 이 False 면, 반환된 객체에 대한 액세스는 록에 의해 자동으로 보호되지 않으므로 “프로세스 안전” 하지 않습니다.

lock 은 키워드 전용 인자입니다.

multiprocessing.sharedctypes.Value(typecode_or_type, *args, lock=True)

lock 값에 따라, 날 ctypes 객체 대신 프로세스 안전한 동기화 래퍼가 반환될 수 있다는 것을 제외하고는 RawValue() 와 같습니다.

lock 이 True (기본값) 면 값에 대한 액세스를 동기화하기 위해 새 록 객체가 생성됩니다. lock 이 Lock 또는 RLock 객체인 경우, 이 값이 값에 대한 액세스를 동기화하는 데 사용됩니다. lock 이 False 면, 반환된 객체에 대한 액세스는 록에 의해 자동으로 보호되지 않으므로 “프로세스 안전” 하지 않습니다.

lock 은 키워드 전용 인자입니다.

multiprocessing.sharedctypes.copy(obj)

공유 메모리에서 할당된 ctypes 객체를 반환합니다. 이 객체는 ctypes 객체 obj 의 복사본입니다.

multiprocessing.sharedctypes.synchronized(obj[, lock])

lock 을 사용하여 액세스를 동기화하는 ctypes 객체에 대한 프로세스 안전한 래퍼 객체를 반환합니다. lock 이 None (기본값)이면 multiprocessing.RLock 객체가 자동으로 생성됩니다.

동기화 래퍼는 래핑 된 객체의 메서드 외에도 두 개의 메서드를 더 갖습니다: get_obj() 는 래핑 된 객체를 반환하고, get_lock() 은 동기화에 사용되는 록 객체를 반환합니다.

래퍼를 통해 ctypes 객체에 액세스하는 것은, 날 ctypes 객체에 액세스하는 것보다 훨씬 느릴 수 있습니다.

버전 3.5에서 변경: 동기화된 객체는 컨텍스트 관리자 프로토콜을 지원합니다.

아래 표는 공유 메모리에 공유 ctypes 객체를 만드는 문법과 일반적인 ctypes 문법을 비교합니다. (표에서 MyStruct 는 ctypes.Structure 의 서브 클래스입니다.)

ctypes

type을 사용하는 공유 ctypes

typecode를 사용하는 공유 ctypes

c_double(2.4)

RawValue(c_double, 2.4)

RawValue(‘d’, 2.4)

MyStruct(4, 6)

RawValue(MyStruct, 4, 6)

(c_short * 7)()

RawArray(c_short, 7)

RawArray(‘h’, 7)

(c_int * 3)(9, 2, 8)

RawArray(c_int, (9, 2, 8))

RawArray(‘i’, (9, 2, 8))

다음은 자식 프로세스가 여러 ctypes 객체를 수정하는 예입니다:

from multiprocessing import Process, Lock
from multiprocessing.sharedctypes import Value, Array
from ctypes import Structure, c_double

class Point(Structure):
    _fields_ = [('x', c_double), ('y', c_double)]

def modify(n, x, s, A):
    n.value **= 2
    x.value **= 2
    s.value = s.value.upper()
    for a in A:
        a.x **= 2
        a.y **= 2

if __name__ == '__main__':
    lock = Lock()

    n = Value('i', 7)
    x = Value(c_double, 1.0/3.0, lock=False)
    s = Array('c', b'hello world', lock=lock)
    A = Array(Point, [(1.875,-6.25), (-5.75,2.0), (2.375,9.5)], lock=lock)

    p = Process(target=modify, args=(n, x, s, A))
    p.start()
    p.join()

    print(n.value)
    print(x.value)
    print(s.value)
    print([(a.x, a.y) for a in A])

인쇄되는 결과는 이렇습니다

49
0.1111111111111111
HELLO WORLD
[(3.515625, 39.0625), (33.0625, 4.0), (5.640625, 90.25)]

관리자

관리자는 서로 다른 컴퓨터에서 실행되는 프로세스 간에 네트워크를 통해 공유하는 것을 포함하여 서로 다른 프로세스 간에 공유할 수 있는 데이터를 만드는 방법을 제공합니다. 관리자 객체는 공유 객체 를 관리하는 서버 프로세스를 제어합니다. 다른 프로세스는 프락시를 사용하여 공유 객체에 액세스 할 수 있습니다.

multiprocessing.Manager()

프로세스 간에 객체를 공유하는 데 사용할 수 있는 시작된 SyncManager 객체를 반환합니다. 반환된 관리자 객체는 생성된 자식 프로세스에 해당하며 공유 객체를 만들고 해당 프락시를 반환하는 메서드가 있습니다.

관리자 프로세스는 가비지 수집되거나 상위 프로세스가 종료되자마자 종료됩니다. 관리자 클래스는 multiprocessing.managers 모듈에 정의되어 있습니다 :

class multiprocessing.managers.BaseManager(address=None, authkey=None, serializer='pickle', ctx=None, *, shutdown_timeout=1.0)

BaseManager 객체를 만듭니다.

일단 생성되면 관리자 객체가 시작된 관리자 프로세스를 참조하게 하려고 start() 또는 get_server().serve_forever() 를 호출해야 합니다.

address 는 관리자 프로세스가 새 연결을 리슨하는 주소입니다. address 가 None 이면 임의의 것이 선택됩니다.

authkey 는 서버 프로세스로 들어오는 연결의 유효성을 검사하는 데 사용되는 인증 키입니다. authkey 가 None 이면 current_process().authkey 가 사용됩니다. 그렇지 않으면 authkey 가 사용되며 바이트열이어야 합니다.

serializer must be 'pickle' (use pickle serialization) or 'xmlrpclib' (use xmlrpc.client serialization).

ctx is a context object, or None (use the current context). See the get_context() function.

shutdown_timeout is a timeout in seconds used to wait until the process used by the manager completes in the shutdown() method. If the shutdown times out, the process is terminated. If terminating the process also times out, the process is killed.

버전 3.11에서 변경: Added the shutdown_timeout parameter.

start([initializer[, initargs]])

관리자를 시작시키기 위해 서브 프로세스를 시작합니다. initializer 가 None 이 아닌 경우, 서브 프로세스는 시작할 때 initializer(*initargs) 를 호출합니다.

get_server()

Manager의 제어를 받는 실제 서버를 나타내는 Server 객체를 반환합니다. Server 객체는 serve_forever() 메서드를 지원합니다:

>>> from multiprocessing.managers import BaseManager
>>> manager = BaseManager(address=('', 50000), authkey=b'abc')
>>> server = manager.get_server()
>>> server.serve_forever()

Server 는 추가로 address 어트리뷰트를 가지고 있습니다.

connect()

지역 관리자 객체를 원격 관리자 프로세스에 연결합니다:

>>> from multiprocessing.managers import BaseManager
>>> m = BaseManager(address=('127.0.0.1', 50000), authkey=b'abc')
>>> m.connect()

shutdown()

관리자가 사용하는 프로세스를 중지합니다. start()를 사용하여 서버 프로세스를 시작한 경우에만 사용할 수 있습니다.

여러 번 호출 될 수 있습니다.

register(typeid[, callable[, proxytype[, exposed[, method_to_typeid[, create_method]]]]])

관리자 클래스에 형이나 콜러블을 등록하는데 사용할 수 있는 클래스 메서드.

typeid 는 특정 형의 공유 객체를 식별하는 데 사용되는 “형 식별자” 입니다. 문자열이어야 합니다.

callable 은 이 형 식별자에 대한 객체를 만드는 데 사용되는 콜러블 객체입니다. 관리자 인스턴스가 connect() 메서드를 사용하여 서버에 연결되거나, create_method 인자가 False 면 None 으로 남겨 둘 수 있습니다.

proxytype 은, 이 typeid 의 공유 객체의 프락시를 만드는 데 사용되는 BaseProxy 의 서브 클래스입니다. None 이면 프락시 클래스가 자동으로 생성됩니다.

exposed 는 이 typeid에 대한 프락시가 BaseProxy._callmethod() 를 사용하여 액세스 할 수 있도록 허용해야 하는 메서드 이름의 시퀀스를 지정하는 데 사용됩니다. (만약 exposed 가 None 이면, 존재하는 경우, proxytype._exposed_ 가 대신 사용됩니다.) exposed 리스트가 지정되지 않은 경우, 공유 객체의 모든 “공용 메서드” 에 액세스 할 수 있습니다. (여기서 “공용 메서드” 는 __call__() 메서드가 있고 그 이름이 '_' 로 시작하지 않는 어트리뷰트를 의미합니다.)

method_to_typeid 는 프락시를 반환해야 하는 노출된 메서드의 반환형을 지정하는 데 사용되는 매핑입니다. 메서드 이름을 typeid 문자열로 매핑합니다. (만일 method_to_typeid 가 None 이면, 존재한다면, proxytype._method_to_typeid_ 가 대신 사용됩니다.) 메서드의 이름이 이 매핑의 키가 아니거나 매핑이 None 이면, 메서드에 의해 반환된 객체는 값으로 복사됩니다.

create_method 는 이름이 typeid 인 메서드를 만들어야 하는지를 결정합니다. 이 메서드는 서버 프로세스에 새 공유 객체를 만들고 프락시를 반환하도록 지시하는 데 사용될 수 있습니다. 기본적으로 True 입니다.

BaseManager 인스턴스는 읽기 전용 프로퍼티를 하나 가지고 있습니다:

address

관리자가 사용하는 주소.

버전 3.3에서 변경: 관리자 객체는 컨텍스트 관리 프로토콜을 지원합니다 – 컨텍스트 관리자 형를 보세요. __enter__() 는 서버 프로세스를 시작하고 (아직 시작하지 않았다면), 관리자 객체를 반환합니다. __exit__() 는 shutdown()을 호출합니다.

이전 버전에서 __enter__() 는 관리자의 서버 프로세스가 아직 시작되지 않았을 때 시작시키지 않았습니다.

class multiprocessing.managers.SyncManager

프로세스의 동기화에 사용할 수 있는 BaseManager 의 서브 클래스입니다. 이 형의 객체는 multiprocessing.Manager() 에 의해 반환됩니다.

이 클래스의 메서드는 여러 프로세스에서 동기화 할 수 있도록 일반적으로 사용되는 많은 데이터형을 생성하고 프락시 객체를 반환합니다. 특히 공유 리스트와 딕셔너리가 포함됩니다.

Barrier(parties[, action[, timeout]])

공유 threading.Barrier 객체를 생성하고 프락시를 반환합니다.

Added in version 3.3.

BoundedSemaphore([value])

공유 threading.BoundedSemaphore 객체를 생성하고 프락시를 반환합니다.

Condition([lock])

공유 threading.Condition 객체를 생성하고 프락시를 반환합니다.

lock 이 제공되면 threading.Lock 또는 threading.RLock 객체에 대한 프락시여야 합니다.

버전 3.3에서 변경: wait_for() 메서드가 추가되었습니다.

Event()

공유 threading.Event 객체를 생성하고 프락시를 반환합니다.

Lock()

공유 threading.Lock 객체를 생성하고 프락시를 반환합니다.

Namespace()

공유 Namespace 객체를 생성하고 프락시를 반환합니다.

Queue([maxsize])

공유 queue.Queue 객체를 생성하고 프락시를 반환합니다.

RLock()

공유 threading.RLock 객체를 생성하고 프락시를 반환합니다.

Semaphore([value])

공유 threading.Semaphore 객체를 생성하고 프락시를 반환합니다.

Array(typecode, sequence)

배열을 만들고 프락시를 반환합니다.

Value(typecode, value)

쓰기 가능한 value 어트리뷰트를 가진 객체를 생성하고 프락시를 반환합니다.

dict()

dict(mapping)

dict(sequence)

공유 dict 객체를 생성하고 프락시를 반환합니다.

list()

list(sequence)

공유 list 객체를 생성하고 프락시를 반환합니다.

버전 3.6에서 변경: 공유 객체는 중첩될 수 있습니다. 예를 들어, 공유 리스트와 같은 공유 컨테이너 객체는, SyncManager 에 의해 모두 관리되고 동기화되는 다른 공유 객체를 포함 할 수 있습니다.

class multiprocessing.managers.Namespace

SyncManager 로 등록 할 수 있는 형입니다.

이름 공간 객체에는 공용 메서드가 없지만, 쓰기 가능한 어트리뷰트가 있습니다. repr 은 그것의 어트리뷰트 값을 보여줍니다.

그러나, 이름 공간 객체의 프락시를 사용할 때, '_' 로 시작하는 어트리뷰트는 프락시의 어트리뷰트가 되며 참조 대상의 어트리뷰트가 아닙니다:

>>> mp_context = multiprocessing.get_context('spawn')
>>> manager = mp_context.Manager()
>>> Global = manager.Namespace()
>>> Global.x = 10
>>> Global.y = 'hello'
>>> Global._z = 12.3    # this is an attribute of the proxy
>>> print(Global)
Namespace(x=10, y='hello')

사용자 정의 관리자

자신만의 관리자를 만들려면, BaseManager 의 서브 클래스를 만들고 register() 클래스 메서드를 사용하여 새로운 형이나 콜러블을 관리자 클래스에 등록합니다. 예를 들면:

from multiprocessing.managers import BaseManager

class MathsClass:
    def add(self, x, y):
        return x + y
    def mul(self, x, y):
        return x * y

class MyManager(BaseManager):
    pass

MyManager.register('Maths', MathsClass)

if __name__ == '__main__':
    with MyManager() as manager:
        maths = manager.Maths()
        print(maths.add(4, 3))         # prints 7
        print(maths.mul(7, 8))         # prints 56

원격 관리자 사용하기

한 기계에서 관리자 서버를 실행하고 다른 기계의 클라이언트가 관리자 서버를 사용하도록 할 수 있습니다 (관련된 방화벽이 허용한다고 가정합니다).

다음 명령을 실행하면 원격 클라이언트가 액세스 할 수 있는 단일 공유 큐를 위한 서버가 만들어집니다:

>>> from multiprocessing.managers import BaseManager
>>> from queue import Queue
>>> queue = Queue()
>>> class QueueManager(BaseManager): pass
>>> QueueManager.register('get_queue', callable=lambda:queue)
>>> m = QueueManager(address=('', 50000), authkey=b'abracadabra')
>>> s = m.get_server()
>>> s.serve_forever()

한 클라이언트는 다음과 같이 서버에 액세스 할 수 있습니다:

>>> from multiprocessing.managers import BaseManager
>>> class QueueManager(BaseManager): pass
>>> QueueManager.register('get_queue')
>>> m = QueueManager(address=('foo.bar.org', 50000), authkey=b'abracadabra')
>>> m.connect()
>>> queue = m.get_queue()
>>> queue.put('hello')

또 다른 클라이언트도 사용할 수 있습니다:

>>> from multiprocessing.managers import BaseManager
>>> class QueueManager(BaseManager): pass
>>> QueueManager.register('get_queue')
>>> m = QueueManager(address=('foo.bar.org', 50000), authkey=b'abracadabra')
>>> m.connect()
>>> queue = m.get_queue()
>>> queue.get()
'hello'

지역 프로세스 역시, 위의 클라이언트가 원격으로 액세스하는 코드를 사용하여 같은 큐에 액세스 할 수 있습니다:

>>> from multiprocessing import Process, Queue
>>> from multiprocessing.managers import BaseManager
>>> class Worker(Process):
...     def __init__(self, q):
...         self.q = q
...         super().__init__()
...     def run(self):
...         self.q.put('local hello')
...
>>> queue = Queue()
>>> w = Worker(queue)
>>> w.start()
>>> class QueueManager(BaseManager): pass
...
>>> QueueManager.register('get_queue', callable=lambda: queue)
>>> m = QueueManager(address=('', 50000), authkey=b'abracadabra')
>>> s = m.get_server()
>>> s.serve_forever()

프락시 객체

프락시는 (아마도) 다른 프로세스에 있는 공유 객체를 가리키는 객체입니다. 공유 객체는 프락시의 지시 대상 이라고 합니다. 여러 프락시 객체는 같은 지시 대상을 가질 수 있습니다.

프락시 객체에는 지시 대상의 해당 메서드를 호출하는 메서드가 있습니다 (그러나 지시 대상의 모든 메서드가 반드시 프락시를 통해 사용할 수 있는 것은 아닙니다). 이런 식으로, 프락시는 지시 대상처럼 사용될 수 있습니다:

>>> mp_context = multiprocessing.get_context('spawn')
>>> manager = mp_context.Manager()
>>> l = manager.list([i*i for i in range(10)])
>>> print(l)
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
>>> print(repr(l))
<ListProxy object, typeid 'list' at 0x...>
>>> l[4]
16
>>> l[2:5]
[4, 9, 16]

프락시에 str() 을 적용하면 지시 대상의 표현이 반환되는 반면, repr() 을 적용하면 프락시의 표현이 반환됩니다.

프락시 객체의 중요한 특징은, 피클 가능해서 프로세스 간에 전달될 수 있다는 것입니다. 지시 대상은 프락시 객체를 포함 할 수 있습니다. 이것은 관리된 리스트, 딕셔너리 및 다른 프락시 객체 의 중첩을 허용합니다:

>>> a = manager.list()
>>> b = manager.list()
>>> a.append(b)         # referent of a now contains referent of b
>>> print(a, b)
[<ListProxy object, typeid 'list' at ...>] []
>>> b.append('hello')
>>> print(a[0], b)
['hello'] ['hello']

비슷하게, 딕셔너리와 리스트 프락시는 서로 중첩될 수 있습니다:

>>> l_outer = manager.list([ manager.dict() for i in range(2) ])
>>> d_first_inner = l_outer[0]
>>> d_first_inner['a'] = 1
>>> d_first_inner['b'] = 2
>>> l_outer[1]['c'] = 3
>>> l_outer[1]['z'] = 26
>>> print(l_outer[0])
{'a': 1, 'b': 2}
>>> print(l_outer[1])
{'c': 3, 'z': 26}

(프락시가 아닌) 표준 list 또는 dict 객체가 지시 대상에 포함되어있는 경우, 이 가변 값들에 대한 수정은 관리자를 통해 전파되지 않습니다. 포함된 값이 언제 수정되는지 프락시가 알 방법이 없기 때문입니다. 그러나 컨테이너 프락시에 값을 저장하는 것(프락시 객체의 __setitem__ 을 호출합니다)은 관리자를 통해 전파되므로, 그 항목을 효과적으로 수정하기 위해, 수정된 값을 컨테이너 프락시에 다시 대입할 수 있습니다:

# create a list proxy and append a mutable object (a dictionary)
lproxy = manager.list()
lproxy.append({})
# now mutate the dictionary
d = lproxy[0]
d['a'] = 1
d['b'] = 2
# at this point, the changes to d are not yet synced, but by
# updating the dictionary, the proxy is notified of the change
lproxy[0] = d

이 접근법은 아마도 대부분의 사용 사례에서 중첩된 프락시 객체를 사용하는 것보다 불편하지만, 동기화에 대한 제어 수준을 보여줍니다.

참고

multiprocessing 의 프락시 형은 값으로 비교하는 것을 지원하지 않습니다. 그래서, 예를 들어, 이런 결과를 얻습니다:

>>> manager.list([1,2,3]) == [1,2,3]
False

비교할 때는 지시 대상의 사본을 대신 사용해야 합니다.

class multiprocessing.managers.BaseProxy

프락시 객체는 BaseProxy 의 서브 클래스의 인스턴스입니다.

_callmethod(methodname[, args[, kwds]])

프락시의 지시 대상 메서드를 호출하고 결과를 반환합니다.

proxy 가 프락시이고, 그 지시 대상이 obj 면, 표현식

proxy._callmethod(methodname, args, kwds)

은 표현식

getattr(obj, methodname)(*args, **kwds)

을 관리자 프로세스에서 평가합니다.

반환된 값은 호출 결과의 복사본이거나 새 공유 객체에 대한 프락시입니다 – BaseManager.register() 의 method_to_typeid 인자에 대한 설명서를 보십시오.

호출 때문에 예외가 발생하면, _callmethod() 가 다시 일으킵니다. 관리자 프로세스에서 다른 예외가 발생하면 RemoteError 예외로 변환되어 _callmethod() 가 일으킵니다.

특히, methodname 이 노출되지 않았으면 예외가 발생합니다.

_callmethod() 사용법의 예:

>>> l = manager.list(range(10))
>>> l._callmethod('__len__')
10
>>> l._callmethod('__getitem__', (slice(2, 7),)) # equivalent to l[2:7]
[2, 3, 4, 5, 6]
>>> l._callmethod('__getitem__', (20,))          # equivalent to l[20]
Traceback (most recent call last):
...
IndexError: list index out of range

_getvalue()

지시 대상의 복사본을 반환합니다.

지시 대상이 피클 가능하지 않으면 예외가 발생합니다.

__repr__()

프락시 객체의 표현을 반환합니다.

__str__()

지시 대상의 표현을 반환합니다.

정리

프락시 객체는 weakref 콜백을 사용해서 가비지 수집 시 자신의 지시 대상을 소유한 관리자에서 자신을 등록 취소합니다.

더는 참조하는 프락시가 없는 경우 공유 객체는 관리자 프로세스에서 삭제됩니다.

프로세스 풀

Pool 클래스를 사용하여, 제출된 작업을 수행할 프로세스 풀을 만들 수 있습니다.

class multiprocessing.pool.Pool([processes[, initializer[, initargs[, maxtasksperchild[, context]]]]])

작업을 제출할 수 있는 작업자 프로세스 풀을 제어하는 프로세스 풀 객체. 제한 시간과 콜백을 사용하는 비동기 결과를 지원하고 병렬 map 구현을 제공합니다.

processes is the number of worker processes to use. If processes is None then the number returned by os.process_cpu_count() is used.

initializer 가 None 이 아니면, 각 작업자 프로세스는 시작할 때 initializer(*initargs) 를 호출합니다.

maxtasksperchild 는, 사용되지 않는 자원을 해제할 수 있도록, 작업 프로세스가 종료되고 새 작업 프로세스로 교체되기 전에 완료할 수 있는 작업 수입니다. 기본 maxtasksperchild 는 None 입니다. 이는 작업자 프로세스가 풀만큼 오래감을 의미합니다.

context 는 작업자 프로세스를 시작하는 데 사용되는 컨텍스트를 지정하는 데 사용할 수 있습니다. 보통 풀은 multiprocessing.Pool() 또는 컨텍스트 객체의 Pool() 메서드를 사용하여 생성됩니다. 두 경우 모두 context 가 적절하게 설정됩니다.

풀 객체의 메서드는 풀을 생성한 프로세스에 의해서만 호출되어야 합니다.

경고

multiprocessing.pool 객체에는 풀을 컨텍스트 관리자로 사용하거나 close()와 terminate()를 수동으로 호출하여 (다른 자원과 마찬가지로) 올바르게 관리해야 하는 내부 자원이 있습니다. 이를 수행하지 않으면 파이널리제이션 때 프로세스가 멈출 수 있습니다.

Note that it is not correct to rely on the garbage collector to destroy the pool as CPython does not assure that the finalizer of the pool will be called (see object.__del__() for more information).

버전 3.2에서 변경: Added the maxtasksperchild parameter.

버전 3.4에서 변경: Added the context parameter.

버전 3.13에서 변경: processes uses os.process_cpu_count() by default, instead of os.cpu_count().

참고

Pool 내의 작업자 프로세스는 일반적으로 Pool의 작업 큐의 전체 지속 기간 지속합니다. 작업자가 잡은 자원을 해제하기 위해 다른 시스템 (가령 Apache, mod_wsgi 등)에서 흔히 사용되는 패턴은, 풀 내에 있는 작업자가 종료되고 새 프로세스가 스폰 되어 예전 것을 교체하기 전에 일정한 분량의 작업만 완료하도록 하는 것입니다. Pool 의 maxtasksperchild 인자는 이 기능을 일반 사용자에게 노출합니다.

apply(func[, args[, kwds]])

인자 args 및 키워드 인자 kwds 를 사용하여 func 를 호출합니다. 결과가 준비될 때까지 블록 됩니다. 이 블록 때문에, apply_async() 가 병렬로 작업을 수행하는 데 더 적합합니다. 또한 func 는 풀의 작업자 중 하나에서만 실행됩니다.

apply_async(func[, args[, kwds[, callback[, error_callback]]]])

AsyncResult 객체를 반환하는 apply() 메서드의 변형입니다.

callback 이 지정되면 단일 인자를 받아들이는 콜러블이어야 합니다. 결과가 준비되면 callback 을 이 결과를 인자로 호출합니다. 실패한 결과면 error_callback 이 대신 적용됩니다.

error_callback 이 지정되면 단일 인자를 허용하는 콜러블이어야 합니다. 대상 함수가 실패하면, error_callback 이 예외 인스턴스를 인자로 호출됩니다.

콜백은 즉시 완료되어야 합니다. 그렇지 않으면 결과를 처리하는 스레드가 블록 됩니다.

map(func, iterable[, chunksize])

map() 내장 함수의 병렬 버전입니다 (하지만 하나의 iterable 인자만 지원합니다, 여러 이터러블에 대해서는 starmap()을 참조하십시오). 결과가 준비될 때까지 블록 됩니다.

이 메서드는 iterable을 여러 묶음으로 잘라서 별도의 작업으로 프로세스 풀에 제출합니다. 이러한 묶음의 (대략적인) 크기는 chunksize 를 양의 정수로 설정하여 지정할 수 있습니다.

매우 긴 이터러블은 높은 메모리 사용을 유발할 수 있습니다. 더 나은 효율성을 위해, 명시적인 chunksize 옵션으로 imap()이나 imap_unordered()를 사용하는 것을 고려하십시오.

map_async(func, iterable[, chunksize[, callback[, error_callback]]])

AsyncResult 객체를 반환하는 map() 메서드의 변형입니다.

callback 이 지정되면 단일 인자를 받아들이는 콜러블이어야 합니다. 결과가 준비되면 callback 을 이 결과를 인자로 호출합니다. 실패한 결과면 error_callback 이 대신 적용됩니다.

error_callback 이 지정되면 단일 인자를 허용하는 콜러블이어야 합니다. 대상 함수가 실패하면, error_callback 이 예외 인스턴스를 인자로 호출됩니다.

콜백은 즉시 완료되어야 합니다. 그렇지 않으면 결과를 처리하는 스레드가 블록 됩니다.

imap(func, iterable[, chunksize])

map() 의 느긋한 버전.

chunksize 인자는 map() 메서드에서 사용된 인자와 같습니다. 매우 긴 iterable의 경우 chunksize 에 큰 값을 사용하면 기본값 1 을 사용하는 것보다 작업을 많이 빠르게 완료 할 수 있습니다.

또한 chunksize 가 1 이면 imap() 메서드에 의해 반환된 이터레이터의 next() 메서드는 선택적 timeout 매개 변수를 가집니다: next(timeout) 은 결과가 timeout 초 내에 반환될 수 없는 경우 multiprocessing.TimeoutError 를 발생시킵니다.

imap_unordered(func, iterable[, chunksize])

imap()과 같지만, 반환된 이터레이터가 제공하는 결과의 순서가 임의적인 것으로 간주하여야 합니다. (단 하나의 작업자 프로세스가 있는 경우에만 순서가 “올바름” 이 보장됩니다.

starmap(func, iterable[, chunksize])

Like map() except that the elements of the iterable are expected to be iterables that are unpacked as arguments.

따라서 iterable 이 [(1,2), (3, 4)] 미면 결과는 [func(1,2), func(3,4)] 가 됩니다.

Added in version 3.3.

starmap_async(func, iterable[, chunksize[, callback[, error_callback]]])

starmap() 과 map_async() 의 조합으로 이터러블의 iterable 을 이터레이트하고 이터러블을 언팩해서 func 를 호출합니다. 결과 객체를 반환합니다.

Added in version 3.3.

close()

더는 작업이 풀에 제출되지 않도록 합니다. 모든 작업이 완료되면 작업자 프로세스가 종료됩니다.

terminate()

계류 중인 작업을 완료하지 않고 즉시 작업자 프로세스를 중지합니다. 풀 객체가 가비지 수집될 때 terminate() 가 즉시 호출됩니다.

join()

작업자 프로세스가 종료될 때까지 기다립니다. join() 호출 전에 반드시 close() 나 terminate()를 호출해야합니다 .

버전 3.3에서 변경: 풀 객체는 이제 컨텍스트 관리 프로토콜을 지원합니다 – 컨텍스트 관리자 형를 보십시오. __enter__() 는 풀 객체를 반환하고, __exit__() 는 terminate()를 호출합니다.

class multiprocessing.pool.AsyncResult

Pool.apply_async()와 Pool.map_async() 에 의해 반환되는 결과의 클래스.

get([timeout])

결과가 도착할 때 반환합니다. timeout 이 None 이 아니고 결과가 timeout 초 내에 도착하지 않으면 multiprocessing.TimeoutError 가 발생합니다. 원격 호출이 예외를 발생시키는 경우 해당 예외는 get() 에 의해 다시 발생합니다.

wait([timeout])

결과가 사용 가능할 때까지 또는 timeout 초가 지날 때까지 기다립니다.

ready()

호출이 완료했는지를 돌려줍니다.

successful()

예외를 발생시키지 않고 호출이 완료되었는지를 돌려줍니다. 결과가 준비되지 않았으면 ValueError 를 발생시킵니다.

버전 3.7에서 변경: 결과가 준비되지 않았으면, AssertionError 대신 ValueError가 발생합니다.

다음 예제는 풀 사용 방법을 보여줍니다.:

from multiprocessing import Pool
import time

def f(x):
    return x*x

if __name__ == '__main__':
    with Pool(processes=4) as pool:         # start 4 worker processes
        result = pool.apply_async(f, (10,)) # evaluate "f(10)" asynchronously in a single process
        print(result.get(timeout=1))        # prints "100" unless your computer is *very* slow

        print(pool.map(f, range(10)))       # prints "[0, 1, 4,..., 81]"

        it = pool.imap(f, range(10))
        print(next(it))                     # prints "0"
        print(next(it))                     # prints "1"
        print(it.next(timeout=1))           # prints "4" unless your computer is *very* slow

        result = pool.apply_async(time.sleep, (10,))
        print(result.get(timeout=1))        # raises multiprocessing.TimeoutError

리스너와 클라이언트

보통 프로세스 간 메시지 전달은 큐를 사용하거나 Pipe() 가 반환하는 Connection 객체를 사용하여 수행됩니다.

그러나, multiprocessing.connection 모듈은 약간의 추가적인 유연성을 허용합니다. 기본적으로 소켓이나 윈도우의 이름있는 파이프를 다루는 높은 수준의 메시지 지향 API를 제공합니다. 또한 hmac 모듈을 사용한 다이제스트 인증 과 다중 연결을 동시에 폴링하는 방법을 지원합니다.

multiprocessing.connection.deliver_challenge(connection, authkey)

무작위로 생성된 메시지를 연결의 다른 쪽 끝으로 보내고 응답을 기다립니다.

응답이 authkey 를 키로 사용하는 메시지의 다이제스트와 일치하면 환영 메시지가 연결의 다른 끝으로 전송됩니다. 그렇지 않으면 AuthenticationError 가 발생합니다.

multiprocessing.connection.answer_challenge(connection, authkey)

메시지를 수신하고, authkey 를 키로 사용하여 메시지의 다이제스트를 계산한 다음, 다이제스트를 다시 보냅니다.

환영 메시지가 수신되지 않으면, AuthenticationError 가 발생합니다.

multiprocessing.connection.Client(address[, family[, authkey]])

주소 address 를 사용하는 리스너에 대한 연결을 설정하려고 시도하고, Connection을 반환합니다.

연결 유형은 family 인자에 의해 결정되지만, 일반적으로 address 형식에서 유추 할 수 있으므로 일반적으로 생략 할 수 있습니다. (주소 형식를 참조하세요)

If authkey is given and not None, it should be a byte string and will be used as the secret key for an HMAC-based authentication challenge. No authentication is done if authkey is None. AuthenticationError is raised if authentication fails. See 인증 키.

class multiprocessing.connection.Listener([address[, family[, backlog[, authkey]]]])

연결을 ‘리스닝’ 하는 바인드된 소켓이나 윈도우의 이름있는 파이프에 대한 래퍼입니다.

address 는 리스너 객체의 바인드된 소켓이나 이름있는 파이프가 사용할 주소입니다.

참고

주소가 ‘0.0.0.0’ 인 경우, 주소는 윈도우에서 연결 가능한 끝점이 아닙니다. 연결할 수 있는 끝점이 필요한 경우, ‘127.0.0.1’을 사용해야 합니다.

family 는 사용할 소켓(또는 이름있는 파이프)의 유형입니다. 문자열 'AF_INET' (TCP 소켓), 'AF_UNIX' (유닉스 도메인 소켓), 'AF_PIPE' (윈도우 이름있는 파이프) 중 하나일 수 있습니다. 이 중 오직 첫 번째 것만 항상 사용할 수 있음이 보장됩니다. family 가 None 이면, address 의 형식으로부터 유추됩니다. address 역시 None 이면, 기본값이 선택됩니다. 이 기본값은 사용 가능한 것 중 가장 빠른 것으로 기대되는 것입니다. 주소 형식를 참조하세요. family 가 'AF_UNIX' 이고 주소가 None 이면, 소켓은 tempfile.mkstemp() 를 사용하여 만들어진 비공개 임시 디렉터리에 생성됩니다.

리스너 객체가 소켓을 사용하면, backlog (기본적으로 1) 는 소켓이 바인드되면 소켓의 listen() 메서드에 전달됩니다.

If authkey is given and not None, it should be a byte string and will be used as the secret key for an HMAC-based authentication challenge. No authentication is done if authkey is None. AuthenticationError is raised if authentication fails. See 인증 키.

accept()

리스너 객체의 바인드된 소켓 또는 이름있는 파이프에 대한 연결을 수락하고 Connection 객체를 반환합니다. 인증이 시도되고 실패하면 AuthenticationError 가 발생합니다.

close()

리스너 객체의 바운드된 소켓 또는 이름있는 파이프를 닫습니다. 리스너가 가비지 수집될 때 자동으로 호출됩니다. 그러나 명시적으로 호출하는 것이 좋습니다.

리스너 객체는 다음과 같은 읽기 전용 프로퍼티를 가집니다:

address

리스너 객체에서 사용 중인 주소.

last_accepted

마지막으로 수락한 연결이 온 주소. 없으면 None 입니다.

버전 3.3에서 변경: 리스너 객체는 컨텍스트 관리 프로토콜을 지원합니다 – 컨텍스트 관리자 형를 보세요. __enter__() 는 리스너 객체를 반환하고, __exit__() 는 close()를 호출합니다.

multiprocessing.connection.wait(object_list, timeout=None)

object_list 에 있는 객체가 준비될 때까지 기다립니다. object_list 에 있는 객체 중 준비된 것들의 리스트를 반환합니다. timeout 이 float면, 호출이 최대 지정된 초만큼 블록 됩니다. timeout 이 None 이면, 시간제한 없이 블록 됩니다. 음수 timeout은 0과 같습니다.

For both POSIX and Windows, an object can appear in object_list if it is

읽기 가능한 Connection 객체;

연결되고 읽기 가능한 socket.socket 객체; 또는

Process 객체의 sentinel 어트리뷰트.

연결이나 소켓 객체는 읽을 수 있는 데이터가 있거나 반대편 끝이 닫히면 준비가 됩니다.

POSIX: wait(object_list, timeout) almost equivalent select.select(object_list, [], [], timeout). The difference is that, if select.select() is interrupted by a signal, it can raise OSError with an error number of EINTR, whereas wait() will not.

Windows: An item in object_list must either be an integer handle which is waitable (according to the definition used by the documentation of the Win32 function WaitForMultipleObjects()) or it can be an object with a fileno() method which returns a socket handle or pipe handle. (Note that pipe handles and socket handles are not waitable handles.)

Added in version 3.3.

예제

다음 서버 코드는 인증 키로 'secret password' 를 사용하는 리스너를 만듭니다. 그런 다음 연결을 기다리고 어떤 데이터를 클라이언트로 보냅니다.:

from multiprocessing.connection import Listener
from array import array

address = ('localhost', 6000)     # family is deduced to be 'AF_INET'

with Listener(address, authkey=b'secret password') as listener:
    with listener.accept() as conn:
        print('connection accepted from', listener.last_accepted)

        conn.send([2.25, None, 'junk', float])

        conn.send_bytes(b'hello')

        conn.send_bytes(array('i', [42, 1729]))

다음 코드는 서버에 연결하고 서버로부터 어떤 데이터를 받습니다:

from multiprocessing.connection import Client
from array import array

address = ('localhost', 6000)

with Client(address, authkey=b'secret password') as conn:
    print(conn.recv())                  # => [2.25, None, 'junk', float]

    print(conn.recv_bytes())            # => 'hello'

    arr = array('i', [0, 0, 0, 0, 0])
    print(conn.recv_bytes_into(arr))    # => 8
    print(arr)                          # => array('i', [42, 1729, 0, 0, 0])

다음 코드는 wait() 을 사용하여 여러 프로세스로부터 오는 메시지를 한 번에 기다립니다:

from multiprocessing import Process, Pipe, current_process
from multiprocessing.connection import wait

def foo(w):
    for i in range(10):
        w.send((i, current_process().name))
    w.close()

if __name__ == '__main__':
    readers = []

    for i in range(4):
        r, w = Pipe(duplex=False)
        readers.append(r)
        p = Process(target=foo, args=(w,))
        p.start()
        # We close the writable end of the pipe now to be sure that
        # p is the only process which owns a handle for it.  This
        # ensures that when p closes its handle for the writable end,
        # wait() will promptly report the readable end as being ready.
        w.close()

    while readers:
        for r in wait(readers):
            try:
                msg = r.recv()
            except EOFError:
                readers.remove(r)
            else:
                print(msg)

주소 형식

'AF_INET' 주소는 (hostname, port) 형식의 튜플입니다. hostname 은 문자열이고, port 는 정수입니다.

'AF_UNIX' 주소는 파일 시스템의 파일 이름을 나타내는 문자열입니다.

An 'AF_PIPE' address is a string of the form r'\\.\pipe\PipeName'. To use Client() to connect to a named pipe on a remote computer called ServerName one should use an address of the form r'\\ServerName\pipe\PipeName' instead.

두 개의 역 슬래시로 시작하는 문자열은 기본적으로 'AF_UNIX' 주소가 아니라 'AF_PIPE' 주소로 간주합니다.

인증 키

Connection.recv 를 사용할 때, 수신된 데이터는 자동으로 언 피클 됩니다. 안타깝게도, 신뢰할 수 없는 출처의 데이터를 언 피클 하는 것은 보안상의 위험입니다. 때문에 Listener와 Client() 는 hmac 모듈을 사용하여 다이제스트 인증을 제공합니다.

인증 키는 암호로 여겨질 수 있는 바이트열입니다: 일단 연결이 이루어지면 양 끝은 다른 쪽이 인증 키를 알고 있음을 증명하도록 요구합니다. (양쪽 끝이 같은 키를 사용하고 있음을 증명하는 데는 연결을 통해 키를 보내는 것을 수반하지 않습니다.)

인증이 요청되었지만 인증 키가 지정되지 않으면, current_process().authkey 의 반환 값이 사용됩니다 (Process 를 보세요). 이 값은 현재 프로세스가 생성하는 Process 객체에 의해 자동으로 상속됩니다. 이것은 다중 프로세스 프로그램의 모든 프로세스는 (기본적으로) 자신들 간의 연결을 설정할 때 사용할 수 있는 하나의 인증 키를 공유한다는 것을 뜻합니다.

적절한 인증 키는 os.urandom() 을 사용하여 생성할 수도 있습니다.

로깅

로깅에 대한 일부 지원이 제공됩니다. 그러나, logging 패키지는 프로세스 공유 록을 사용하지 않으므로 (처리기형에 따라) 다른 프로세스의 메시지가 뒤섞일 가능성이 있습니다.

multiprocessing.get_logger()

multiprocessing에서 사용되는 로거를 반환합니다. 필요하다면, 새로운 것이 만들어집니다.

When first created the logger has level logging.NOTSET and no default handler. Messages sent to this logger will not by default propagate to the root logger.

윈도우에서 자식 프로세스는 부모 프로세스의 로거의 수준만 상속받습니다 – 그 밖의 다른 로거 사용자 지정은 상속되지 않습니다.

multiprocessing.log_to_stderr(level=None)

This function performs a call to get_logger() but in addition to returning the logger created by get_logger, it adds a handler which sends output to sys.stderr using format '[%(levelname)s/%(processName)s] %(message)s'. You can modify levelname of the logger by passing a level argument.

다음은 로깅이 켜져 있는 예제 세션입니다:

>>> import multiprocessing, logging
>>> logger = multiprocessing.log_to_stderr()
>>> logger.setLevel(logging.INFO)
>>> logger.warning('doomed')
[WARNING/MainProcess] doomed
>>> m = multiprocessing.Manager()
[INFO/SyncManager-...] child process calling self.run()
[INFO/SyncManager-...] created temp directory /.../pymp-...
[INFO/SyncManager-...] manager serving at '/.../listener-...'
>>> del m
[INFO/MainProcess] sending shutdown message to manager
[INFO/SyncManager-...] manager exiting with exitcode 0

로깅 수준의 전체 표는 logging 모듈을 참조하십시오.

multiprocessing.dummy 모듈

multiprocessing.dummy 는 multiprocessing 의 API를 복제하지만 threading 모듈에 대한 래퍼일 뿐입니다.

특히, multiprocessing.dummy에서 제공하는 Pool 함수는 같은 메서드 호출을 모두 지원하지만, 작업자 프로세스가 아닌 작업자 스레드 풀을 사용하는 Pool의 서브 클래스인 ThreadPool의 인스턴스를 반환합니다.

class multiprocessing.pool.ThreadPool([processes[, initializer[, initargs]]])

작업을 제출할 수 있는 작업자 스레드 풀을 제어하는 스레드 풀 객체. ThreadPool 인스턴스는 Pool 인스턴스와 완전히 호환되며, 해당 리소스는 컨텍스트 관리자로 풀을 사용하거나 close()와 terminate()를 수동으로 호출하여 적절하게 관리해야 합니다.

processes is the number of worker threads to use. If processes is None then the number returned by os.process_cpu_count() is used.

initializer 가 None 이 아니면, 각 작업자 프로세스는 시작할 때 initializer(*initargs) 를 호출합니다.

Pool과 달리, maxtasksperchild와 context는 제공할 수 없습니다.

참고

ThreadPool은 프로세스 풀을 중심으로 설계되고 concurrent.futures 모듈 도입 이전에 설계된 Pool과 같은 인터페이스를 공유합니다. 따라서, 스레드가 지원하는 풀에 적합하지 않은 일부 연산을 상속하고, 비동기 작업의 상태를 나타내는 자체 형 AsyncResult를 가지고 있는데 다른 라이브러리에서는 이해하지 못합니다.

사용자는 일반적으로 처음부터 스레드를 중심으로 설계되고 asyncio를 포함한 다른 많은 라이브러리와 호환되는 concurrent.futures.Future 인스턴스를 반환하는 더 간단한 인터페이스를 가진 concurrent.futures.ThreadPoolExecutor를 사용하는 것을 선호해야 합니다.

프로그래밍 지침

multiprocessing를 사용할 때 준수해야 할 지침과 관용구가 있습니다.

모든 시작 방법

다음은 모든 시작 방법에 적용됩니다.

공유 상태를 피하세요

가능한 한 프로세스 간에 많은 양의 데이터가 이동하지 않도록 해야 합니다.

저수준 동기화 프리미티브를 사용하기보다, 프로세스 간 통신을 위해 큐나 파이프를 사용하는 것이 아마도 최선입니다.

피클 가능성

프락시 메서드에 대한 인자가 피클 가능한지 확인하십시오.

프락시의 스레드 안전성

록으로 보호하지 않는 한 둘 이상의 스레드에서 프락시 객체를 사용하지 마십시오.

(여러 프로세스가 같은 프락시를 사용하는 문제는 존재하지 않습니다.)

좀비 프로세스 조인하기

On POSIX when a process finishes but has not been joined it becomes a zombie. There should never be very many because each time a new process starts (or active_children() is called) all completed processes which have not yet been joined will be joined. Also calling a finished process’s Process.is_alive will join the process. Even so it is probably good practice to explicitly join all the processes that you start.

피클/언 피클보다 상속하는 것이 더 좋습니다.

spawn 이나 forkserver 시작 방법을 사용할 때, multiprocessing 의 여러 형은 자식 프로세스가 사용할 수 있도록 피클 가능할 필요가 있습니다. 그러나, 일반적으로 파이프나 큐를 사용하여 공유 객체를 다른 프로세스로 보내는 것을 피해야 합니다. 대신 다른 곳에 만들어진 공유 자원에 접근해야 하는 프로세스가 조상 프로세스에서 그것들을 상속받을 수 있도록 프로그램을 배치해야 합니다.

프로세스 강제 종료를 피하세요

Process.terminate 메서드를 사용해서 프로세스를 정지시키는 것은, 그 프로세스가 현재 사용하고 있는 공유 자원(가령 록, 세마포어, 파이프, 큐)을 손상하거나 다른 프로세스에서 사용할 수 없게 만들 수 있습니다.

따라서, 아마도 어떤 공유 자원도 사용하지 않는 프로세스에만 Process.terminate 사용을 고려하는 것이 최선일 겁니다.

큐를 사용하는 프로세스 조인하기

큐에 항목을 넣은 프로세스는 종료되기 전에 버퍼링 된 모든 항목이 “피더” 스레드에 의해 하부 파이프로 공급될 때까지 대기합니다. (자식 프로세스는 Queue.cancel_join_thread 메서드를 호출해서 이 동작을 회피할 수 있습니다.)

이것은, 큐를 사용할 때마다 큐에 넣은 모든 항목이 결국 프로세스가 조인되기 전에 제거되도록 해야 함을 의미합니다. 그렇지 않으면 큐에 항목을 넣은 프로세스가 종료되리라고 보장할 수 없습니다. 데몬이 아닌 프로세스가 자동으로 조인된다는 것도 기억하세요.

교착 상태에 빠지는 예는 다음과 같습니다:

from multiprocessing import Process, Queue

def f(q):
    q.put('X' * 1000000)

if __name__ == '__main__':
    queue = Queue()
    p = Process(target=f, args=(queue,))
    p.start()
    p.join()                    # this deadlocks
    obj = queue.get()

이 문제를 고치는 방법은 마지막 두 줄의 순서를 바꾸는 것입니다 (또는 간단히 p.join() 줄을 지우는 것입니다).

자식 프로세스에 자원을 명시적으로 전달하세요.

On POSIX using the fork start method, a child process can make use of a shared resource created in a parent process using a global resource. However, it is better to pass the object as an argument to the constructor for the child process.

윈도우 및 다른 시작 방법과 (잠재적으로) 호환될 수 있는 코드를 만드는 것 외에도, 이것은 자식 프로세스가 아직 살아있는 동안 객체가 부모 프로세스에서 가비지 수집되지 않음을 보장합니다. 부모 프로세스에서 그 객체가 가비지 수집될 때 일부 자원이 해제되면 이것이 중요 할 수 있습니다.

그래서 예를 들면

from multiprocessing import Process, Lock

def f():
    ... do something using "lock" ...

if __name__ == '__main__':
    lock = Lock()
    for i in range(10):
        Process(target=f).start()

는 다음과 같이 다시 써야 합니다

from multiprocessing import Process, Lock

def f(l):
    ... do something using "l" ...

if __name__ == '__main__':
    lock = Lock()
    for i in range(10):
        Process(target=f, args=(lock,)).start()

sys.stdin 을 “파일류 객체”로 교체할 때 조심하세요

multiprocessing은 원래 무조건 다음과 같이 호출했습니다

os.close(sys.stdin.fileno())

multiprocessing.Process._bootstrap() 메서드에서 하는 작업입니다 — 이것은 손자 프로세스와 관련된 문제로 이어졌습니다. 이것은 다음과 같이 변경되었습니다:

sys.stdin.close()
sys.stdin = open(os.open(os.devnull, os.O_RDONLY), closefd=False)

Which solves the fundamental issue of processes colliding with each other resulting in a bad file descriptor error, but introduces a potential danger to applications which replace sys.stdin() with a “file-like object” with output buffering. This danger is that if multiple processes call close() on this file-like object, it could result in the same data being flushed to the object multiple times, resulting in corruption.

파일류 객체를 작성하고 여러분 자신의 캐싱을 구현하면, 캐시에 추가할 때마다 pid를 저장하고, pid가 변경되면 캐시를 버려서 포크에 안전하게 만들 수 있습니다. 예를 들면:

@property
def cache(self):
    pid = os.getpid()
    if pid != self._pid:
        self._pid = pid
        self._cache = []
    return self._cache

자세한 내용은 bpo-5155 [https://bugs.python.org/issue?@action=redirect&bpo=5155], bpo-5313 [https://bugs.python.org/issue?@action=redirect&bpo=5313] 및 bpo-5331 [https://bugs.python.org/issue?@action=redirect&bpo=5331]을 참조하십시오.

spawn 과 forkserver 시작 방법

There are a few extra restrictions which don’t apply to the fork start method.

더 높은 피클 가능성

Process.__init__() 에 대한 모든 인자가 피클 가능한지 확인하십시오. 또한, Process 의 서브 클래스를 만들면, Process.start 메서드가 호출될 때 그 인스턴스가 피클 가능하도록 해야 합니다.

전역 변수

자식 프로세스에서 실행되는 코드가 전역 변수에 접근하려고 시도하면, 그 값은 (있는 경우) Process.start 가 호출되는 시점의 부모 프로세스의 값과 같지 않을 수 있습니다.

하지만, 모듈 수준의 상수인 전역 변수는 문제가 되지 않습니다.

메인 모듈의 안전한 임포트

Make sure that the main module can be safely imported by a new Python interpreter without causing unintended side effects (such as starting a new process).

예를 들어, spawn 또는 forkserver 시작 방법을 사용해서 다음 모듈을 실행하면 RuntimeError 로 실패합니다:

from multiprocessing import Process

def foo():
    print('hello')

p = Process(target=foo)
p.start()

대신 다음과 같이 if __name__ == '__main__': 을 사용하여 프로그램의 “진입 지점”을 보호해야 합니다:

from multiprocessing import Process, freeze_support, set_start_method

def foo():
    print('hello')

if __name__ == '__main__':
    freeze_support()
    set_start_method('spawn')
    p = Process(target=foo)
    p.start()

(freeze_support() 줄은 프로그램이 프로즌 되지 않고 정상적으로 실행될 경우 생략될 수 있습니다.)

이것은 새로 스폰 된 파이썬 인터프리터가 모듈을 안전하게 임포트 한 다음 모듈의 foo() 함수를 실행할 수 있게 해줍니다.

메인 모듈에서 풀이나 관리자를 만들면 비슷한 제한이 적용됩니다.

예제

사용자 정의된 관리자와 프락시를 만들고 사용하는 방법에 대한 시연:

from multiprocessing import freeze_support
from multiprocessing.managers import BaseManager, BaseProxy
import operator

##

class Foo:
    def f(self):
        print('you called Foo.f()')
    def g(self):
        print('you called Foo.g()')
    def _h(self):
        print('you called Foo._h()')

# A simple generator function
def baz():
    for i in range(10):
        yield i*i

# Proxy type for generator objects
class GeneratorProxy(BaseProxy):
    _exposed_ = ['__next__']
    def __iter__(self):
        return self
    def __next__(self):
        return self._callmethod('__next__')

# Function to return the operator module
def get_operator_module():
    return operator

##

class MyManager(BaseManager):
    pass

# register the Foo class; make `f()` and `g()` accessible via proxy
MyManager.register('Foo1', Foo)

# register the Foo class; make `g()` and `_h()` accessible via proxy
MyManager.register('Foo2', Foo, exposed=('g', '_h'))

# register the generator function baz; use `GeneratorProxy` to make proxies
MyManager.register('baz', baz, proxytype=GeneratorProxy)

# register get_operator_module(); make public functions accessible via proxy
MyManager.register('operator', get_operator_module)

##

def test():
    manager = MyManager()
    manager.start()

    print('-' * 20)

    f1 = manager.Foo1()
    f1.f()
    f1.g()
    assert not hasattr(f1, '_h')
    assert sorted(f1._exposed_) == sorted(['f', 'g'])

    print('-' * 20)

    f2 = manager.Foo2()
    f2.g()
    f2._h()
    assert not hasattr(f2, 'f')
    assert sorted(f2._exposed_) == sorted(['g', '_h'])

    print('-' * 20)

    it = manager.baz()
    for i in it:
        print('<%d>' % i, end=' ')
    print()

    print('-' * 20)

    op = manager.operator()
    print('op.add(23, 45) =', op.add(23, 45))
    print('op.pow(2, 94) =', op.pow(2, 94))
    print('op._exposed_ =', op._exposed_)

##

if __name__ == '__main__':
    freeze_support()
    test()

Pool 사용하기:

import multiprocessing
import time
import random
import sys

#
# Functions used by test code
#

def calculate(func, args):
    result = func(*args)
    return '%s says that %s%s = %s' % (
        multiprocessing.current_process().name,
        func.__name__, args, result
        )

def calculatestar(args):
    return calculate(*args)

def mul(a, b):
    time.sleep(0.5 * random.random())
    return a * b

def plus(a, b):
    time.sleep(0.5 * random.random())
    return a + b

def f(x):
    return 1.0 / (x - 5.0)

def pow3(x):
    return x ** 3

def noop(x):
    pass

#
# Test code
#

def test():
    PROCESSES = 4
    print('Creating pool with %d processes\n' % PROCESSES)

    with multiprocessing.Pool(PROCESSES) as pool:
        #
        # Tests
        #

        TASKS = [(mul, (i, 7)) for i in range(10)] + \
                [(plus, (i, 8)) for i in range(10)]

        results = [pool.apply_async(calculate, t) for t in TASKS]
        imap_it = pool.imap(calculatestar, TASKS)
        imap_unordered_it = pool.imap_unordered(calculatestar, TASKS)

        print('Ordered results using pool.apply_async():')
        for r in results:
            print('\t', r.get())
        print()

        print('Ordered results using pool.imap():')
        for x in imap_it:
            print('\t', x)
        print()

        print('Unordered results using pool.imap_unordered():')
        for x in imap_unordered_it:
            print('\t', x)
        print()

        print('Ordered results using pool.map() --- will block till complete:')
        for x in pool.map(calculatestar, TASKS):
            print('\t', x)
        print()

        #
        # Test error handling
        #

        print('Testing error handling:')

        try:
            print(pool.apply(f, (5,)))
        except ZeroDivisionError:
            print('\tGot ZeroDivisionError as expected from pool.apply()')
        else:
            raise AssertionError('expected ZeroDivisionError')

        try:
            print(pool.map(f, list(range(10))))
        except ZeroDivisionError:
            print('\tGot ZeroDivisionError as expected from pool.map()')
        else:
            raise AssertionError('expected ZeroDivisionError')

        try:
            print(list(pool.imap(f, list(range(10)))))
        except ZeroDivisionError:
            print('\tGot ZeroDivisionError as expected from list(pool.imap())')
        else:
            raise AssertionError('expected ZeroDivisionError')

        it = pool.imap(f, list(range(10)))
        for i in range(10):
            try:
                x = next(it)
            except ZeroDivisionError:
                if i == 5:
                    pass
            except StopIteration:
                break
            else:
                if i == 5:
                    raise AssertionError('expected ZeroDivisionError')

        assert i == 9
        print('\tGot ZeroDivisionError as expected from IMapIterator.next()')
        print()

        #
        # Testing timeouts
        #

        print('Testing ApplyResult.get() with timeout:', end=' ')
        res = pool.apply_async(calculate, TASKS[0])
        while 1:
            sys.stdout.flush()
            try:
                sys.stdout.write('\n\t%s' % res.get(0.02))
                break
            except multiprocessing.TimeoutError:
                sys.stdout.write('.')
        print()
        print()

        print('Testing IMapIterator.next() with timeout:', end=' ')
        it = pool.imap(calculatestar, TASKS)
        while 1:
            sys.stdout.flush()
            try:
                sys.stdout.write('\n\t%s' % it.next(0.02))
            except StopIteration:
                break
            except multiprocessing.TimeoutError:
                sys.stdout.write('.')
        print()
        print()

if __name__ == '__main__':
    multiprocessing.freeze_support()
    test()

큐를 사용하여 작업을 작업자 프로세스 집단에 제공하고 결과를 수집하는 방법을 보여주는 예:

import time
import random

from multiprocessing import Process, Queue, current_process, freeze_support

#
# Function run by worker processes
#

def worker(input, output):
    for func, args in iter(input.get, 'STOP'):
        result = calculate(func, args)
        output.put(result)

#
# Function used to calculate result
#

def calculate(func, args):
    result = func(*args)
    return '%s says that %s%s = %s' % \
        (current_process().name, func.__name__, args, result)

#
# Functions referenced by tasks
#

def mul(a, b):
    time.sleep(0.5*random.random())
    return a * b

def plus(a, b):
    time.sleep(0.5*random.random())
    return a + b

#
#
#

def test():
    NUMBER_OF_PROCESSES = 4
    TASKS1 = [(mul, (i, 7)) for i in range(20)]
    TASKS2 = [(plus, (i, 8)) for i in range(10)]

    # Create queues
    task_queue = Queue()
    done_queue = Queue()

    # Submit tasks
    for task in TASKS1:
        task_queue.put(task)

    # Start worker processes
    for i in range(NUMBER_OF_PROCESSES):
        Process(target=worker, args=(task_queue, done_queue)).start()

    # Get and print results
    print('Unordered results:')
    for i in range(len(TASKS1)):
        print('\t', done_queue.get())

    # Add more tasks using `put()`
    for task in TASKS2:
        task_queue.put(task)

    # Get and print some more results
    for i in range(len(TASKS2)):
        print('\t', done_queue.get())

    # Tell child processes to stop
    for i in range(NUMBER_OF_PROCESSES):
        task_queue.put('STOP')

if __name__ == '__main__':
    freeze_support()
    test()

multiprocessing.shared_memory — Shared memory for direct access across processes

소스 코드: Lib/multiprocessing/shared_memory.py [https://github.com/python/cpython/tree/main/Lib/multiprocessing/shared_memory.py]

Added in version 3.8.

This module provides a class, SharedMemory, for the allocation and management of shared memory to be accessed by one or more processes on a multicore or symmetric multiprocessor (SMP) machine. To assist with the life-cycle management of shared memory especially across distinct processes, a BaseManager subclass, SharedMemoryManager, is also provided in the multiprocessing.managers module.

In this module, shared memory refers to “POSIX style” shared memory blocks (though is not necessarily implemented explicitly as such) and does not refer to “distributed shared memory”. This style of shared memory permits distinct processes to potentially read and write to a common (or shared) region of volatile memory. Processes are conventionally limited to only have access to their own process memory space but shared memory permits the sharing of data between processes, avoiding the need to instead send messages between processes containing that data. Sharing data directly via memory can provide significant performance benefits compared to sharing data via disk or socket or other communications requiring the serialization/deserialization and copying of data.

class multiprocessing.shared_memory.SharedMemory(name=None, create=False, size=0, *, track=True)

Create an instance of the SharedMemory class for either creating a new shared memory block or attaching to an existing shared memory block. Each shared memory block is assigned a unique name. In this way, one process can create a shared memory block with a particular name and a different process can attach to that same shared memory block using that same name.

As a resource for sharing data across processes, shared memory blocks may outlive the original process that created them. When one process no longer needs access to a shared memory block that might still be needed by other processes, the close() method should be called. When a shared memory block is no longer needed by any process, the unlink() method should be called to ensure proper cleanup.

매개변수:

name (str | None) – The unique name for the requested shared memory, specified as a string. When creating a new shared memory block, if None (the default) is supplied for the name, a novel name will be generated.

create (bool) – Control whether a new shared memory block is created (True) or an existing shared memory block is attached (False).

size (int) – The requested number of bytes when creating a new shared memory block. Because some platforms choose to allocate chunks of memory based upon that platform’s memory page size, the exact size of the shared memory block may be larger or equal to the size requested. When attaching to an existing shared memory block, the size parameter is ignored.

track (bool) – When True, register the shared memory block with a resource tracker process on platforms where the OS does not do this automatically. The resource tracker ensures proper cleanup of the shared memory even if all other processes with access to the memory exit without doing so. Python processes created from a common ancestor using multiprocessing facilities share a single resource tracker process, and the lifetime of shared memory segments is handled automatically among these processes. Python processes created in any other way will receive their own resource tracker when accessing shared memory with track enabled. This will cause the shared memory to be deleted by the resource tracker of the first process that terminates. To avoid this issue, users of subprocess or standalone Python processes should set track to False when there is already another process in place that does the bookkeeping. track is ignored on Windows, which has its own tracking and automatically deletes shared memory when all handles to it have been closed.

버전 3.13에서 변경: Added the track parameter.

close()

Close the file descriptor/handle to the shared memory from this instance. close() should be called once access to the shared memory block from this instance is no longer needed. Depending on operating system, the underlying memory may or may not be freed even if all handles to it have been closed. To ensure proper cleanup, use the unlink() method.

unlink()

Delete the underlying shared memory block. This should be called only once per shared memory block regardless of the number of handles to it, even in other processes. unlink() and close() can be called in any order, but trying to access data inside a shared memory block after unlink() may result in memory access errors, depending on platform.

This method has no effect on Windows, where the only way to delete a shared memory block is to close all handles.

buf

공유 메모리 블록의 내용에 대한 메모리 뷰.

name

공유 메모리 블록의 고유한 이름에 대한 읽기 전용 액세스.

size

공유 메모리 블록의 크기(바이트)에 대한 읽기 전용 액세스.

다음 예제는 SharedMemory 인스턴스의 저수준 사용을 보여줍니다:

>>> from multiprocessing import shared_memory
>>> shm_a = shared_memory.SharedMemory(create=True, size=10)
>>> type(shm_a.buf)
<class 'memoryview'>
>>> buffer = shm_a.buf
>>> len(buffer)
10
>>> buffer[:4] = bytearray([22, 33, 44, 55])  # Modify multiple at once
>>> buffer[4] = 100                           # Modify single byte at a time
>>> # Attach to an existing shared memory block
>>> shm_b = shared_memory.SharedMemory(shm_a.name)
>>> import array
>>> array.array('b', shm_b.buf[:5])  # Copy the data into a new array.array
array('b', [22, 33, 44, 55, 100])
>>> shm_b.buf[:5] = b'howdy'  # Modify via shm_b using bytes
>>> bytes(shm_a.buf[:5])      # Access via shm_a
b'howdy'
>>> shm_b.close()   # Close each SharedMemory instance
>>> shm_a.close()
>>> shm_a.unlink()  # Call unlink only once to release the shared memory

The following example demonstrates a practical use of the SharedMemory class with NumPy arrays [https://numpy.org/], accessing the same numpy.ndarray from two distinct Python shells:

>>> # In the first Python interactive shell
>>> import numpy as np
>>> a = np.array([1, 1, 2, 3, 5, 8])  # Start with an existing NumPy array
>>> from multiprocessing import shared_memory
>>> shm = shared_memory.SharedMemory(create=True, size=a.nbytes)
>>> # Now create a NumPy array backed by shared memory
>>> b = np.ndarray(a.shape, dtype=a.dtype, buffer=shm.buf)
>>> b[:] = a[:]  # Copy the original data into shared memory
>>> b
array([1, 1, 2, 3, 5, 8])
>>> type(b)
<class 'numpy.ndarray'>
>>> type(a)
<class 'numpy.ndarray'>
>>> shm.name  # We did not specify a name so one was chosen for us
'psm_21467_46075'

>>> # In either the same shell or a new Python shell on the same machine
>>> import numpy as np
>>> from multiprocessing import shared_memory
>>> # Attach to the existing shared memory block
>>> existing_shm = shared_memory.SharedMemory(name='psm_21467_46075')
>>> # Note that a.shape is (6,) and a.dtype is np.int64 in this example
>>> c = np.ndarray((6,), dtype=np.int64, buffer=existing_shm.buf)
>>> c
array([1, 1, 2, 3, 5, 8])
>>> c[-1] = 888
>>> c
array([  1,   1,   2,   3,   5, 888])

>>> # Back in the first Python interactive shell, b reflects this change
>>> b
array([  1,   1,   2,   3,   5, 888])

>>> # Clean up from within the second Python shell
>>> del c  # Unnecessary; merely emphasizing the array is no longer used
>>> existing_shm.close()

>>> # Clean up from within the first Python shell
>>> del b  # Unnecessary; merely emphasizing the array is no longer used
>>> shm.close()
>>> shm.unlink()  # Free and release the shared memory block at the very end

class multiprocessing.managers.SharedMemoryManager([address[, authkey]])

A subclass of multiprocessing.managers.BaseManager which can be used for the management of shared memory blocks across processes.

A call to start() on a SharedMemoryManager instance causes a new process to be started. This new process’s sole purpose is to manage the life cycle of all shared memory blocks created through it. To trigger the release of all shared memory blocks managed by that process, call shutdown() on the instance. This triggers a unlink() call on all of the SharedMemory objects managed by that process and then stops the process itself. By creating SharedMemory instances through a SharedMemoryManager, we avoid the need to manually track and trigger the freeing of shared memory resources.

이 클래스는 SharedMemory 인스턴스를 만들고 반환하는 메서드와, 공유 메모리로 지원되는 리스트류 객체(ShareableList)를 만드는 메서드를 제공합니다.

Refer to BaseManager for a description of the inherited address and authkey optional input arguments and how they may be used to connect to an existing SharedMemoryManager service from other processes.

SharedMemory(size)

Create and return a new SharedMemory object with the specified size in bytes.

ShareableList(sequence)

Create and return a new ShareableList object, initialized by the values from the input sequence.

The following example demonstrates the basic mechanisms of a SharedMemoryManager:

>>> from multiprocessing.managers import SharedMemoryManager
>>> smm = SharedMemoryManager()
>>> smm.start()  # Start the process that manages the shared memory blocks
>>> sl = smm.ShareableList(range(4))
>>> sl
ShareableList([0, 1, 2, 3], name='psm_6572_7512')
>>> raw_shm = smm.SharedMemory(size=128)
>>> another_sl = smm.ShareableList('alpha')
>>> another_sl
ShareableList(['a', 'l', 'p', 'h', 'a'], name='psm_6572_12221')
>>> smm.shutdown()  # Calls unlink() on sl, raw_shm, and another_sl

The following example depicts a potentially more convenient pattern for using SharedMemoryManager objects via the with statement to ensure that all shared memory blocks are released after they are no longer needed:

>>> with SharedMemoryManager() as smm:
...     sl = smm.ShareableList(range(2000))
...     # Divide the work among two processes, storing partial results in sl
...     p1 = Process(target=do_work, args=(sl, 0, 1000))
...     p2 = Process(target=do_work, args=(sl, 1000, 2000))
...     p1.start()
...     p2.start()  # A multiprocessing.Pool might be more efficient
...     p1.join()
...     p2.join()   # Wait for all work to complete in both processes
...     total_result = sum(sl)  # Consolidate the partial results now in sl

When using a SharedMemoryManager in a with statement, the shared memory blocks created using that manager are all released when the with statement’s code block finishes execution.

class multiprocessing.shared_memory.ShareableList(sequence=None, *, name=None)

Provide a mutable list-like object where all values stored within are stored in a shared memory block. This constrains storable values to the following built-in data types:

int (signed 64-bit)

float

bool

str (less than 10M bytes each when encoded as UTF-8)

bytes (less than 10M bytes each)

None

It also notably differs from the built-in list type in that these lists can not change their overall length (i.e. no append(), insert(), etc.) and do not support the dynamic creation of new ShareableList instances via slicing.

sequence is used in populating a new ShareableList full of values. Set to None to instead attach to an already existing ShareableList by its unique shared memory name.

name is the unique name for the requested shared memory, as described in the definition for SharedMemory. When attaching to an existing ShareableList, specify its shared memory block’s unique name while leaving sequence set to None.

참고

A known issue exists for bytes and str values. If they end with \x00 nul bytes or characters, those may be silently stripped when fetching them by index from the ShareableList. This .rstrip(b'\x00') behavior is considered a bug and may go away in the future. See gh-106939 [https://github.com/python/cpython/issues/106939].

For applications where rstripping of trailing nulls is a problem, work around it by always unconditionally appending an extra non-0 byte to the end of such values when storing and unconditionally removing it when fetching:

>>> from multiprocessing import shared_memory
>>> nul_bug_demo = shared_memory.ShareableList(['?\x00', b'\x03\x02\x01\x00\x00\x00'])
>>> nul_bug_demo[0]
'?'
>>> nul_bug_demo[1]
b'\x03\x02\x01'
>>> nul_bug_demo.shm.unlink()
>>> padded = shared_memory.ShareableList(['?\x00\x07', b'\x03\x02\x01\x00\x00\x00\x07'])
>>> padded[0][:-1]
'?\x00'
>>> padded[1][:-1]
b'\x03\x02\x01\x00\x00\x00'
>>> padded.shm.unlink()

count(value)

Return the number of occurrences of value.

index(value)

Return first index position of value. Raise ValueError if value is not present.

format

현재 저장된 모든 값이 사용하는 struct 패킹 형식을 포함하는 읽기 전용 어트리뷰트.

shm

값이 저장되는 SharedMemory 인스턴스.

다음 예제는 ShareableList 인스턴스의 기본 사용을 보여줍니다.:

>>> from multiprocessing import shared_memory
>>> a = shared_memory.ShareableList(['howdy', b'HoWdY', -273.154, 100, None, True, 42])
>>> [ type(entry) for entry in a ]
[<class 'str'>, <class 'bytes'>, <class 'float'>, <class 'int'>, <class 'NoneType'>, <class 'bool'>, <class 'int'>]
>>> a[2]
-273.154
>>> a[2] = -78.5
>>> a[2]
-78.5
>>> a[2] = 'dry ice'  # Changing data types is supported as well
>>> a[2]
'dry ice'
>>> a[2] = 'larger than previously allocated storage space'
Traceback (most recent call last):
  ...
ValueError: exceeds available storage for existing str
>>> a[2]
'dry ice'
>>> len(a)
7
>>> a.index(42)
6
>>> a.count(b'howdy')
0
>>> a.count(b'HoWdY')
1
>>> a.shm.close()
>>> a.shm.unlink()
>>> del a  # Use of a ShareableList after call to unlink() is unsupported

다음 예는 하나, 둘 또는 여러 프로세스가 그 뒤에 있는 공유 메모리 블록의 이름을 제공하여 같은 ShareableList에 액세스하는 방법을 보여줍니다:

>>> b = shared_memory.ShareableList(range(5))         # In a first process
>>> c = shared_memory.ShareableList(name=b.shm.name)  # In a second process
>>> c
ShareableList([0, 1, 2, 3, 4], name='...')
>>> c[-1] = -999
>>> b[-1]
-999
>>> b.shm.close()
>>> c.shm.close()
>>> c.shm.unlink()

The following examples demonstrates that ShareableList (and underlying SharedMemory) objects can be pickled and unpickled if needed. Note, that it will still be the same shared object. This happens, because the deserialized object has the same unique name and is just attached to an existing object with the same name (if the object is still alive):

>>> import pickle
>>> from multiprocessing import shared_memory
>>> sl = shared_memory.ShareableList(range(10))
>>> list(sl)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> deserialized_sl = pickle.loads(pickle.dumps(sl))
>>> list(deserialized_sl)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> sl[0] = -1
>>> deserialized_sl[1] = -2
>>> list(sl)
[-1, -2, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(deserialized_sl)
[-1, -2, 2, 3, 4, 5, 6, 7, 8, 9]

>>> sl.shm.close()
>>> sl.shm.unlink()

The concurrent package

현재, 이 패키지에는 하나의 모듈만 있습니다.:

concurrent.futures – 병렬 작업 시작하기

concurrent.futures — Launching parallel tasks

Added in version 3.2.

소스 코드: Lib/concurrent/futures/thread.py [https://github.com/python/cpython/tree/main/Lib/concurrent/futures/thread.py]와 Lib/concurrent/futures/process.py [https://github.com/python/cpython/tree/main/Lib/concurrent/futures/process.py]

concurrent.futures 모듈은 비동기적으로 콜러블을 실행하는 고수준 인터페이스를 제공합니다.

The asynchronous execution can be performed with threads, using ThreadPoolExecutor or InterpreterPoolExecutor, or separate processes, using ProcessPoolExecutor. Each implements the same interface, which is defined by the abstract Executor class.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

Executor 객체

class concurrent.futures.Executor

비동기적으로 호출을 실행하는 메서드를 제공하는 추상 클래스입니다. 직접 사용해서는 안 되며, 구체적인 하위 클래스를 통해 사용해야 합니다.

submit(fn, /, *args, **kwargs)

Schedules the callable, fn, to be executed as fn(*args, **kwargs) and returns a Future object representing the execution of the callable.

with ThreadPoolExecutor(max_workers=1) as executor:
    future = executor.submit(pow, 323, 1235)
    print(future.result())

map(fn, *iterables, timeout=None, chunksize=1)

Similar to map(fn, *iterables) except:

iterables 는 느긋하게 처리되는 것이 아니라 즉시 수집됩니다.

fn is executed asynchronously and several calls to fn may be made concurrently.

The returned iterator raises a TimeoutError if __next__() is called and the result isn’t available after timeout seconds from the original call to Executor.map(). timeout can be an int or a float. If timeout is not specified or None, there is no limit to the wait time.

If a fn call raises an exception, then that exception will be raised when its value is retrieved from the iterator.

When using ProcessPoolExecutor, this method chops iterables into a number of chunks which it submits to the pool as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer. For very long iterables, using a large value for chunksize can significantly improve performance compared to the default size of 1. With ThreadPoolExecutor and InterpreterPoolExecutor, chunksize has no effect.

버전 3.5에서 변경: chunksize 인자가 추가되었습니다.

shutdown(wait=True, *, cancel_futures=False)

현재 계류 중인 퓨처가 실행 완료될 때, 사용 중인 모든 자원을 해제해야 한다는 것을 실행기에 알립니다. 종료(shutdown) 후에 이루어지는 Executor.submit() 과 Executor.map() 호출은 RuntimeError 를 발생시킵니다.

wait 가 True 면, 계류 중인 모든 퓨처가 실행을 마치고 실행기와 관련된 자원이 해제될 때까지 이 메서드는 돌아오지 않습니다. wait 가 False 면, 이 메서드는 즉시 돌아오고 실행기와 연관된 자원은 계류 중인 모든 퓨처가 실행을 마칠 때 해제됩니다. wait 의 값과 관계없이, 모든 계류 중인 퓨처가 실행을 마칠 때까지 전체 파이썬 프로그램이 종료되지 않습니다.

cancel_futures가 True이면, 이 메서드는 실행기가 실행을 시작시키지 않은 계류 중인 모든 퓨처를 취소합니다. cancel_futures의 값과 관계없이 완료되었거나 실행 중인 퓨처는 취소되지 않습니다.

cancel_futures와 wait가 모두 True이면, 이 메서드가 반환하기 전에 실행기가 실행을 시작한 모든 퓨처가 완료됩니다. 나머지 퓨처는 취소됩니다.

with 문을 사용하여 Executor를 종료시키면 (Executor.shutdown() 를 wait 값 True 로 호출한 것처럼 대기합니다), 이 메서드를 명시적으로 호출할 필요가 없어집니다.:

import shutil
with ThreadPoolExecutor(max_workers=4) as e:
    e.submit(shutil.copy, 'src1.txt', 'dest1.txt')
    e.submit(shutil.copy, 'src2.txt', 'dest2.txt')
    e.submit(shutil.copy, 'src3.txt', 'dest3.txt')
    e.submit(shutil.copy, 'src4.txt', 'dest4.txt')

버전 3.9에서 변경: cancel_futures를 추가했습니다.

ThreadPoolExecutor

ThreadPoolExecutor 는 스레드 풀을 사용하여 호출을 비동기적으로 실행하는 Executor 서브 클래스입니다.

Future와 관련된 콜러블 객체가 다른 Future 의 결과를 기다릴 때 교착 상태가 발생할 수 있습니다. 예를 들면:

import time
def wait_on_b():
    time.sleep(5)
    print(b.result())  # b will never complete because it is waiting on a.
    return 5

def wait_on_a():
    time.sleep(5)
    print(a.result())  # a will never complete because it is waiting on b.
    return 6

executor = ThreadPoolExecutor(max_workers=2)
a = executor.submit(wait_on_b)
b = executor.submit(wait_on_a)

그리고:

def wait_on_future():
    f = executor.submit(pow, 5, 2)
    # This will never complete because there is only one worker thread and
    # it is executing this function.
    print(f.result())

executor = ThreadPoolExecutor(max_workers=1)
executor.submit(wait_on_future)

class concurrent.futures.ThreadPoolExecutor(max_workers=None, thread_name_prefix='', initializer=None, initargs=())

최대 max_workers 스레드의 풀을 사용하여 호출을 비동기적으로 실행하는 Executor 서브 클래스.

All threads enqueued to ThreadPoolExecutor will be joined before the interpreter can exit. Note that the exit handler which does this is executed before any exit handlers added using atexit. This means exceptions in the main thread must be caught and handled in order to signal threads to exit gracefully. For this reason, it is recommended that ThreadPoolExecutor not be used for long-running tasks.

initializer 는 각 작업자 스레드의 시작 부분에서 호출되는 선택적 콜러블입니다; initargs 는 initializer에 전달되는 인자들의 튜플입니다. initializer 가 예외를 발생시키는 경우, 현재 계류 중인 모든 작업과 풀에 추가로 작업을 제출하려는 시도는 BrokenThreadPool 을 발생시킵니다.

버전 3.5에서 변경: max_workers 가 None 이거나 주어지지 않았다면, 기본값으로 기계의 프로세서 수에 5 를 곱한 값을 사용합니다. ThreadPoolExecutor 가 CPU 작업보다는 I/O를 동시에 진행하는데 자주 쓰이고, 작업자의 수가 ProcessPoolExecutor 보다 많아야 한다고 가정하고 있습니다.

버전 3.6에서 변경: Added the thread_name_prefix parameter to allow users to control the threading.Thread names for worker threads created by the pool for easier debugging.

버전 3.7에서 변경: initializer 및 initargs 인자가 추가되었습니다.

버전 3.8에서 변경: max_workers의 기본값은 min(32, os.cpu_count() + 4)로 변경됩니다. 이 기본값은 I/O 병목 작업을 위해 최소 5개의 작업자를 유지합니다. GIL을 반납하는 CPU 병목 작업을 위해 최대 32개의 CPU 코어를 사용합니다. 또한 많은 코어를 가진 시스템에서 매우 큰 자원을 묵시적으로 사용하는 것을 방지합니다.

ThreadPoolExecutor는 이제 max_workers 작업자 스레드를 시작하기 전에 유휴 작업자 스레드를 재사용합니다.

버전 3.13에서 변경: Default value of max_workers is changed to min(32, (os.process_cpu_count() or 1) + 4).

ThreadPoolExecutor 예제

import concurrent.futures
import urllib.request

URLS = ['http://www.foxnews.com/',
        'http://www.cnn.com/',
        'http://europe.wsj.com/',
        'http://www.bbc.co.uk/',
        'http://nonexistent-subdomain.python.org/']

# Retrieve a single page and report the URL and contents
def load_url(url, timeout):
    with urllib.request.urlopen(url, timeout=timeout) as conn:
        return conn.read()

# We can use a with statement to ensure threads are cleaned up promptly
with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:
    # Start the load operations and mark each future with its URL
    future_to_url = {executor.submit(load_url, url, 60): url for url in URLS}
    for future in concurrent.futures.as_completed(future_to_url):
        url = future_to_url[future]
        try:
            data = future.result()
        except Exception as exc:
            print('%r generated an exception: %s' % (url, exc))
        else:
            print('%r page is %d bytes' % (url, len(data)))

InterpreterPoolExecutor

The InterpreterPoolExecutor class uses a pool of interpreters to execute calls asynchronously. It is a ThreadPoolExecutor subclass, which means each worker is running in its own thread. The difference here is that each worker has its own interpreter, and runs each task using that interpreter.

The biggest benefit to using interpreters instead of only threads is true multi-core parallelism. Each interpreter has its own Global Interpreter Lock, so code running in one interpreter can run on one CPU core, while code in another interpreter runs unblocked on a different core.

The tradeoff is that writing concurrent code for use with multiple interpreters can take extra effort. However, this is because it forces you to be deliberate about how and when interpreters interact, and to be explicit about what data is shared between interpreters. This results in several benefits that help balance the extra effort, including true multi-core parallelism, For example, code written this way can make it easier to reason about concurrency. Another major benefit is that you don’t have to deal with several of the big pain points of using threads, like race conditions.

Each worker’s interpreter is isolated from all the other interpreters. “Isolated” means each interpreter has its own runtime state and operates completely independently. For example, if you redirect sys.stdout in one interpreter, it will not be automatically redirected any other interpreter. If you import a module in one interpreter, it is not automatically imported in any other. You would need to import the module separately in interpreter where you need it. In fact, each module imported in an interpreter is a completely separate object from the same module in a different interpreter, including sys, builtins, and even __main__.

Isolation means a mutable object, or other data, cannot be used by more than one interpreter at the same time. That effectively means interpreters cannot actually share such objects or data. Instead, each interpreter must have its own copy, and you will have to synchronize any changes between the copies manually. Immutable objects and data, like the builtin singletons, strings, and tuples of immutable objects, don’t have these limitations.

Communicating and synchronizing between interpreters is most effectively done using dedicated tools, like those proposed in PEP 734 [https://peps.python.org/pep-0734/]. One less efficient alternative is to serialize with pickle and then send the bytes over a shared socket or pipe.

class concurrent.futures.InterpreterPoolExecutor(max_workers=None, thread_name_prefix='', initializer=None, initargs=(), shared=None)

A ThreadPoolExecutor subclass that executes calls asynchronously using a pool of at most max_workers threads. Each thread runs tasks in its own interpreter. The worker interpreters are isolated from each other, which means each has its own runtime state and that they can’t share any mutable objects or other data. Each interpreter has its own Global Interpreter Lock, which means code run with this executor has true multi-core parallelism.

The optional initializer and initargs arguments have the same meaning as for ThreadPoolExecutor: the initializer is run when each worker is created, though in this case it is run.in the worker’s interpreter. The executor serializes the initializer and initargs using pickle when sending them to the worker’s interpreter.

참고

Functions defined in the __main__ module cannot be pickled and thus cannot be used.

참고

The executor may replace uncaught exceptions from initializer with ExecutionFailed.

The optional shared argument is a dict of objects that all interpreters in the pool share. The shared items are added to each interpreter’s __main__ module. Not all objects are shareable. Shareable objects include the builtin singletons, str and bytes, and memoryview. See PEP 734 [https://peps.python.org/pep-0734/] for more info.

Other caveats from parent ThreadPoolExecutor apply here.

submit() and map() work like normal, except the worker serializes the callable and arguments using pickle when sending them to its interpreter. The worker likewise serializes the return value when sending it back.

참고

Functions defined in the __main__ module cannot be pickled and thus cannot be used.

When a worker’s current task raises an uncaught exception, the worker always tries to preserve the exception as-is. If that is successful then it also sets the __cause__ to a corresponding ExecutionFailed instance, which contains a summary of the original exception. In the uncommon case that the worker is not able to preserve the original as-is then it directly preserves the corresponding ExecutionFailed instance instead.

ProcessPoolExecutor

ProcessPoolExecutor 클래스는 프로세스 풀을 사용하여 호출을 비동기적으로 실행하는 Executor 서브 클래스입니다. ProcessPoolExecutor 는 multiprocessing 모듈을 사용합니다. 전역 인터프리터 록 을 피할 수 있도록 하지만, 오직 피클 가능한 객체만 실행되고 반환될 수 있음을 의미합니다.

__main__ 모듈은 작업자 서브 프로세스가 임포트 할 수 있어야 합니다. 즉, ProcessPoolExecutor 는 대화형 인터프리터에서 작동하지 않습니다.

ProcessPoolExecutor 에 제출된 콜러블에서 Executor 나 Future 메서드를 호출하면 교착 상태가 발생합니다.

class concurrent.futures.ProcessPoolExecutor(max_workers=None, mp_context=None, initializer=None, initargs=(), max_tasks_per_child=None)

An Executor subclass that executes calls asynchronously using a pool of at most max_workers processes. If max_workers is None or not given, it will default to os.process_cpu_count(). If max_workers is less than or equal to 0, then a ValueError will be raised. On Windows, max_workers must be less than or equal to 61. If it is not then ValueError will be raised. If max_workers is None, then the default chosen will be at most 61, even if more processors are available. mp_context can be a multiprocessing context or None. It will be used to launch the workers. If mp_context is None or not given, the default multiprocessing context is used. See 컨텍스트 및 시작 방법.

initializer 는 각 작업자 프로세스의 시작 부분에서 호출되는 선택적 콜러블입니다; initargs 는 initializer에 전달되는 인자들의 튜플입니다. initializer 가 예외를 발생시키는 경우, 현재 계류 중인 모든 작업과 풀에 추가로 작업을 제출하려는 시도는 BrokenProcessPool 을 발생시킵니다.

max_tasks_per_child is an optional argument that specifies the maximum number of tasks a single process can execute before it will exit and be replaced with a fresh worker process. By default max_tasks_per_child is None which means worker processes will live as long as the pool. When a max is specified, the “spawn” multiprocessing start method will be used by default in absence of a mp_context parameter. This feature is incompatible with the “fork” start method.

버전 3.3에서 변경: When one of the worker processes terminates abruptly, a BrokenProcessPool error is now raised. Previously, behaviour was undefined but operations on the executor or its futures would often freeze or deadlock.

버전 3.7에서 변경: mp_context 인자가 추가되어 사용자가 풀에서 만드는 작업자 프로세스의 시작 방법을 제어 할 수 있습니다.

initializer 및 initargs 인자가 추가되었습니다.

버전 3.11에서 변경: The max_tasks_per_child argument was added to allow users to control the lifetime of workers in the pool.

버전 3.12에서 변경: On POSIX systems, if your application has multiple threads and the multiprocessing context uses the "fork" start method: The os.fork() function called internally to spawn workers may raise a DeprecationWarning. Pass a mp_context configured to use a different start method. See the os.fork() documentation for further explanation.

버전 3.13에서 변경: max_workers uses os.process_cpu_count() by default, instead of os.cpu_count().

버전 3.14에서 변경: The default process start method (see 컨텍스트 및 시작 방법) changed away from fork. If you require the fork start method for ProcessPoolExecutor you must explicitly pass mp_context=multiprocessing.get_context("fork").

ProcessPoolExecutor 예제

import concurrent.futures
import math

PRIMES = [
    112272535095293,
    112582705942171,
    112272535095293,
    115280095190773,
    115797848077099,
    1099726899285419]

def is_prime(n):
    if n < 2:
        return False
    if n == 2:
        return True
    if n % 2 == 0:
        return False

    sqrt_n = int(math.floor(math.sqrt(n)))
    for i in range(3, sqrt_n + 1, 2):
        if n % i == 0:
            return False
    return True

def main():
    with concurrent.futures.ProcessPoolExecutor() as executor:
        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
            print('%d is prime: %s' % (number, prime))

if __name__ == '__main__':
    main()

Future 객체

Future 클래스는 콜러블 객체의 비동기 실행을 캡슐화합니다. Future 인스턴스는 Executor.submit() 에 의해 생성됩니다.

class concurrent.futures.Future

콜러블 객체의 비동기 실행을 캡슐화합니다. Future 인스턴스는 Executor.submit() 에 의해 생성되며 테스트를 제외하고는 직접 생성되어서는 안 됩니다.

cancel()

호출을 취소하려고 시도합니다. 호출이 현재 실행 중이거나 실행 종료했고 취소할 수 없는 경우 메서드는 False 를 반환하고, 그렇지 않으면 호출이 취소되고 메서드는 True 를 반환합니다.

cancelled()

호출이 성공적으로 취소되었으면 True 를 반환합니다.

running()

호출이 현재 실행 중이고 취소할 수 없는 경우 True 를 반환합니다.

done()

호출이 성공적으로 취소되었거나 실행이 완료되었으면 True 를 반환합니다.

result(timeout=None)

Return the value returned by the call. If the call hasn’t yet completed then this method will wait up to timeout seconds. If the call hasn’t completed in timeout seconds, then a TimeoutError will be raised. timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time.

완료하기 전에 퓨처가 취소되면 CancelledError 가 발생합니다.

If the call raised an exception, this method will raise the same exception.

exception(timeout=None)

Return the exception raised by the call. If the call hasn’t yet completed then this method will wait up to timeout seconds. If the call hasn’t completed in timeout seconds, then a TimeoutError will be raised. timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time.

완료하기 전에 퓨처가 취소되면 CancelledError 가 발생합니다.

호출이 예외 없이 완료되면, None 이 반환됩니다.

add_done_callback(fn)

콜러블 fn 을 퓨처에 연결합니다. fn 은 퓨처가 취소되거나 실행이 종료될 때 퓨처를 유일한 인자로 호출됩니다.

추가된 콜러블은 추가된 순서대로 호출되며, 항상 콜러블을 추가한 프로세스에 속하는 스레드에서 호출됩니다. 콜러블이 Exception 서브 클래스를 발생시키면, 로그 되고 무시됩니다. 콜러블이 BaseException 서브 클래스를 발생시키면, 동작은 정의되지 않습니다.

퓨처가 이미 완료되었거나 취소된 경우 fn 이 즉시 호출됩니다.

다음 Future 메서드는 단위 테스트와 Executor 의 구현을 위한 것입니다.

set_running_or_notify_cancel()

이 메서드는 Future와 관련된 작업을 실행하기 전에 Executor 구현에 의해서만 호출되거나 단위 테스트에서만 호출되어야 합니다.

If the method returns False then the Future was cancelled, i.e. Future.cancel() was called and returned True. Any threads waiting on the Future completing (i.e. through as_completed() or wait()) will be woken up.

If the method returns True then the Future was not cancelled and has been put in the running state, i.e. calls to Future.running() will return True.

이 메서드는 한 번만 호출 할 수 있으며, Future.set_result() 또는 Future.set_exception() 이 호출 된 후에는 호출할 수 없습니다.

set_result(result)

Future와 관련된 작업 결과를 result 로 설정합니다.

이 메서드는 Executor 구현과 단위 테스트에서만 사용해야 합니다.

버전 3.8에서 변경: 이 메서드는 Future가 이미 완료되었으면 concurrent.futures.InvalidStateError를 발생시킵니다.

set_exception(exception)

Future와 관련된 작업 결과를 Exception exception 으로 설정합니다.

이 메서드는 Executor 구현과 단위 테스트에서만 사용해야 합니다.

버전 3.8에서 변경: 이 메서드는 Future가 이미 완료되었으면 concurrent.futures.InvalidStateError를 발생시킵니다.

모듈 함수

concurrent.futures.wait(fs, timeout=None, return_when=ALL_COMPLETED)

Wait for the Future instances (possibly created by different Executor instances) given by fs to complete. Duplicate futures given to fs are removed and will be returned only once. Returns a named 2-tuple of sets. The first set, named done, contains the futures that completed (finished or cancelled futures) before the wait completed. The second set, named not_done, contains the futures that did not complete (pending or running futures).

timeout 은 반환하기 전에 대기 할 최대 시간(초)을 제어하는 데 사용할 수 있습니다. timeout 은 int 또는 float가 될 수 있습니다. timeout 이 지정되지 않았거나 None 인 경우, 대기 시간에는 제한이 없습니다.

return_when 은, 이 함수가 언제 반환되어야 하는지를 나타냅니다. 다음 상수 중 하나여야 합니다:

상수

설명

concurrent.futures.FIRST_COMPLETED

퓨처가 어느 하나라도 끝나거나 취소될 때 함수가 반환됩니다.

concurrent.futures.FIRST_EXCEPTION

The function will return when any future finishes by raising an exception. If no future raises an exception then it is equivalent to ALL_COMPLETED.

concurrent.futures.ALL_COMPLETED

모든 퓨처가 끝나거나 취소되면 함수가 반환됩니다.

concurrent.futures.as_completed(fs, timeout=None)

Returns an iterator over the Future instances (possibly created by different Executor instances) given by fs that yields futures as they complete (finished or cancelled futures). Any futures given by fs that are duplicated will be returned once. Any futures that completed before as_completed() is called will be yielded first. The returned iterator raises a TimeoutError if __next__() is called and the result isn’t available after timeout seconds from the original call to as_completed(). timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time.

더 보기

PEP 3148 [https://peps.python.org/pep-3148/] – 퓨처 - 계산을 비동기적으로 실행

파이썬 표준 라이브러리에 포함하기 위해, 이 기능을 설명한 제안.

예외 클래스

exception concurrent.futures.CancelledError

퓨처가 취소될 때 발생합니다.

exception concurrent.futures.TimeoutError

A deprecated alias of TimeoutError, raised when a future operation exceeds the given timeout.

버전 3.11에서 변경: This class was made an alias of TimeoutError.

exception concurrent.futures.BrokenExecutor

RuntimeError 에서 파생됩니다, 이 예외 클래스는 어떤 이유로 실행기가 망가져서 새 작업을 제출하거나 실행할 수 없을 때 발생합니다.

Added in version 3.7.

exception concurrent.futures.InvalidStateError

퓨처에 현재 상태에서 허용되지 않는 연산이 수행될 때 발생합니다.

Added in version 3.8.

exception concurrent.futures.thread.BrokenThreadPool

Derived from BrokenExecutor, this exception class is raised when one of the workers of a ThreadPoolExecutor has failed initializing.

Added in version 3.7.

exception concurrent.futures.interpreter.BrokenInterpreterPool

Derived from BrokenThreadPool, this exception class is raised when one of the workers of a InterpreterPoolExecutor has failed initializing.

Added in version 3.14.

exception concurrent.futures.interpreter.ExecutionFailed

Raised from InterpreterPoolExecutor when the given initializer fails or from submit() when there’s an uncaught exception from the submitted task.

Added in version 3.14.

exception concurrent.futures.process.BrokenProcessPool

Derived from BrokenExecutor (formerly RuntimeError), this exception class is raised when one of the workers of a ProcessPoolExecutor has terminated in a non-clean fashion (for example, if it was killed from the outside).

Added in version 3.3.

subprocess — Subprocess management

소스 코드: Lib/subprocess.py [https://github.com/python/cpython/tree/main/Lib/subprocess.py]

subprocess 모듈은 새로운 프로세스를 생성하고, 그들의 입력/출력/에러 파이프에 연결하고, 반환 코드를 얻을 수 있도록 합니다. 이 모듈은 몇 가지 이전 모듈과 함수를 대체하려고 합니다:

os.system
os.spawn*

subprocess 모듈을 사용하여 이러한 모듈과 함수를 교체하는 방법에 대한 정보는 다음 섹션에서 확인할 수 있습니다.

더 보기

PEP 324 [https://peps.python.org/pep-0324/] – subprocess 모듈을 제안하는 PEP

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

subprocess 모듈 사용하기

서브 프로세스 호출에 권장되는 접근법은 처리할 수 있는 모든 사용 사례에 run() 함수를 사용하는 것입니다. 고급 사용 사례의 경우, 하부 Popen 인터페이스를 직접 사용할 수 있습니다.

subprocess.run(args, *, stdin=None, input=None, stdout=None, stderr=None, capture_output=False, shell=False, cwd=None, timeout=None, check=False, encoding=None, errors=None, text=None, env=None, universal_newlines=None, **other_popen_kwargs)

args가 기술하는 명령을 실행합니다. 명령이 완료될 때까지 기다린 다음, CompletedProcess 인스턴스를 반환합니다.

위에 표시된 인자는 가장 일반적인 인자로, 아래 자주 사용되는 인자에서 설명됩니다 (따라서 약식 서명에 키워드 전용 표기법을 사용합니다). 전체 함수 서명은 Popen 생성자와 거의 같습니다 - 이 함수에 대한 대부분의 인자는 해당 인터페이스로 전달됩니다. (timeout, input, check 및 capture_output은 아닙니다.)

If capture_output is true, stdout and stderr will be captured. When used, the internal Popen object is automatically created with stdout and stderr both set to PIPE. The stdout and stderr arguments may not be supplied at the same time as capture_output. If you wish to capture and combine both streams into one, set stdout to PIPE and stderr to STDOUT, instead of using capture_output.

A timeout may be specified in seconds, it is internally passed on to Popen.communicate(). If the timeout expires, the child process will be killed and waited for. The TimeoutExpired exception will be re-raised after the child process has terminated. The initial process creation itself cannot be interrupted on many platform APIs so you are not guaranteed to see a timeout exception until at least after however long process creation takes.

The input argument is passed to Popen.communicate() and thus to the subprocess’s stdin. If used it must be a byte sequence, or a string if encoding or errors is specified or text is true. When used, the internal Popen object is automatically created with stdin set to PIPE, and the stdin argument may not be used as well.

check가 참이고, 프로세스가 0이 아닌 종료 코드로 종료되면, CalledProcessError 예외가 발생합니다. 해당 예외의 어트리뷰트가 인자 및 종료 코드와 캡처되었다면 stdout과 stderr을 담습니다.

encoding이나 errors가 지정되거나, text가 참이면, stdin, stdout 및 stderr의 파일 객체는 지정된 encoding과 errors 또는 io.TextIOWrapper 기본값을 사용하여 텍스트 모드로 열립니다. universal_newlines 인자는 text와 동등하고 이전 버전과의 호환성을 위해 제공됩니다. 기본적으로, 파일 객체는 바이너리 모드로 열립니다.

If env is not None, it must be a mapping that defines the environment variables for the new process; these are used instead of the default behavior of inheriting the current process’ environment. It is passed directly to Popen. This mapping can be str to str on any platform or bytes to bytes on POSIX platforms much like os.environ or os.environb.

예:

>>> subprocess.run(["ls", "-l"])  # doesn't capture output
CompletedProcess(args=['ls', '-l'], returncode=0)

>>> subprocess.run("exit 1", shell=True, check=True)
Traceback (most recent call last):
  ...
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

>>> subprocess.run(["ls", "-l", "/dev/null"], capture_output=True)
CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n', stderr=b'')

Added in version 3.5.

버전 3.6에서 변경: encoding과 errors 매개 변수를 추가했습니다

버전 3.7에서 변경: universal_newlines의 더 이해하기 쉬운 별칭으로 text 매개 변수를 추가했습니다. capture_output 매개 변수를 추가했습니다.

버전 3.12에서 변경: Changed Windows shell search order for shell=True. The current directory and %PATH% are replaced with %COMSPEC% and %SystemRoot%\System32\cmd.exe. As a result, dropping a malicious program named cmd.exe into a current directory no longer works.

class subprocess.CompletedProcess

완료된 프로세스를 나타내는, run()의 반환 값.

args

프로세스를 시작하는 데 사용된 인자. 리스트나 문자열일 수 있습니다.

returncode

자식 프로세스의 종료 상태. 일반적으로, 종료 상태 0은 성공적으로 실행되었음을 나타냅니다.

음수 값 -N은 자식이 시그널 N에 의해 종료되었음을 나타냅니다 (POSIX 전용).

stdout

자식 프로세스에서 캡처된 stdout. 바이트 시퀀스, 또는 run()이 encoding, errors, 또는 text=True로 호출되었으면 문자열. stdout이 캡처되지 않았으면 None.

stderr=subprocess.STDOUT으로 프로세스를 실행했으면, stdout과 stderr이 이 어트리뷰트에 결합하고, stderr은 None이 됩니다.

stderr

자식 프로세스에서 캡처된 stderr. 바이트 시퀀스, 또는 run()이 encoding, errors, 또는 text=True로 호출되었으면 문자열. stderr이 캡처되지 않았으면 None.

check_returncode()

returncode가 0이 아니면, CalledProcessError를 발생시킵니다.

Added in version 3.5.

subprocess.DEVNULL

Popen의 stdin, stdout 또는 stderr 인자로 사용할 수 있고 특수 파일 os.devnull이 사용될 것임을 나타내는 특수 값.

Added in version 3.3.

subprocess.PIPE

Popen의 stdin, stdout 또는 stderr 인자로 사용할 수 있고 표준 스트림에 대한 파이프를 열어야 함을 나타내는 특수 값. Popen.communicate()에서 가장 유용합니다.

subprocess.STDOUT

Popen의 stderr 인자로 사용할 수 있고 표준 에러가 표준 출력과 같은 핸들로 가야 함을 나타내는 특수 값.

exception subprocess.SubprocessError

이 모듈의 다른 모든 예외에 대한 베이스 클래스.

Added in version 3.3.

exception subprocess.TimeoutExpired

자식 프로세스를 기다리는 동안 시간제한이 만료될 때 발생하는 SubprocessError의 서브 클래스.

cmd

자식 프로세스를 생성하는 데 사용된 명령.

timeout

초 단위의 시간제한.

output

Output of the child process if it was captured by run() or check_output(). Otherwise, None. This is always bytes when any output was captured regardless of the text=True setting. It may remain None instead of b'' when no output was observed.

stdout

output의 별칭, stderr과의 대칭을 위한 것입니다.

stderr

Stderr output of the child process if it was captured by run(). Otherwise, None. This is always bytes when stderr output was captured regardless of the text=True setting. It may remain None instead of b'' when no stderr output was observed.

Added in version 3.3.

버전 3.5에서 변경: stdout과 stderr 어트리뷰트가 추가되었습니다

exception subprocess.CalledProcessError

Subclass of SubprocessError, raised when a process run by check_call(), check_output(), or run() (with check=True) returns a non-zero exit status.

returncode

자식 프로세스의 종료 상태. 시그널로 인해 프로세스가 종료되었으면, 음의 시그널 번호가 됩니다.

cmd

자식 프로세스를 생성하는 데 사용된 명령.

output

run()이나 check_output()에 의해 캡처되었다면 자식 프로세스의 출력. 그렇지 않으면, None.

stdout

output의 별칭, stderr과의 대칭을 위한 것입니다.

stderr

run()에 의해 캡처되었다면 자식 프로세스의 stderr 출력. 그렇지 않으면, None.

버전 3.5에서 변경: stdout과 stderr 어트리뷰트가 추가되었습니다

자주 사용되는 인자

다양한 사용 사례를 지원하기 위해, Popen 생성자(및 편의 함수)는 많은 선택적 인자를 받아들입니다. 가장 일반적인 사용 사례에서, 이러한 인자 중 많은 부분을 기본값으로 안전하게 남겨둘 수 있습니다. 가장 흔히 필요한 인자는 다음과 같습니다:

args는 모든 호출에 필요하며 문자열 또는 프로그램 인자의 시퀀스여야 합니다. 인자의 시퀀스를 제공하는 것이 일반적으로 선호되는데, 모듈이 필요한 인자의 이스케이프와 인용을 처리하도록 하기 때문입니다 (예를 들어 파일 이름에 공백을 허용하도록). 단일 문자열을 전달하면, shell이 True(아래를 참조하십시오)이거나, 그렇지 않으면 문자열은 단순히 인자를 지정하지 않고 실행할 프로그램의 이름이어야 합니다.

stdin, stdout and stderr specify the executed program’s standard input, standard output and standard error file handles, respectively. Valid values are None, PIPE, DEVNULL, an existing file descriptor (a positive integer), and an existing file object with a valid file descriptor. With the default settings of None, no redirection will occur. PIPE indicates that a new pipe to the child should be created. DEVNULL indicates that the special file os.devnull will be used. Additionally, stderr can be STDOUT, which indicates that the stderr data from the child process should be captured into the same file handle as for stdout.

encoding이나 errors가 지정되거나, text(universal_newlines라고도 합니다)가 참이면, 파일 객체 stdin, stdout 및 stderr은 호출에 지정된 encoding과 errors 또는 io.TextIOWrapper의 기본값을 사용하여 텍스트 모드로 열립니다.

stdin의 경우, 입력의 줄 종료 문자 '\n'이 기본 줄 구분자 os.linesep으로 변환됩니다. stdout과 stderr의 경우, 출력의 모든 줄 종료가 '\n'으로 변환됩니다. 자세한 정보는 생성자에 대한 newline 인자가 None일 때에 관한 io.TextIOWrapper 클래스의 설명서를 참조하십시오.

텍스트 모드를 사용하지 않으면, stdin, stdout 및 stderr이 바이너리 스트림으로 열립니다. 인코딩이나 줄 종료 변환이 수행되지 않습니다.

버전 3.6에서 변경: Added the encoding and errors parameters.

버전 3.7에서 변경: text 매개 변수를 universal_newlines의 별칭으로 추가했습니다.

참고

파일 객체 Popen.stdin, Popen.stdout 및 Popen.stderr의 newlines 어트리뷰트는 Popen.communicate() 메서드에 의해 갱신되지 않습니다.

shell이 True이면, 지정된 명령이 셸을 통해 실행됩니다. 이것은 대부분의 시스템 셸에서 제공하는 것보다 향상된 제어 흐름을 위해 파이썬을 주로 사용하면서, 여전히 셸 파이프, 파일명 와일드카드, 환경 변수 확장 및 사용자 홈 디렉터리로의 ~ 확장과 같은 다른 셸 기능에 대한 편리한 액세스를 원할 때 유용할 수 있습니다. 그러나, 파이썬 자체가 많은 셸과 유사한 기능의 구현을 제공함에 유의하십시오 (특히, glob, fnmatch, os.walk(), os.path.expandvars(), os.path.expanduser() 및 shutil).

버전 3.3에서 변경: universal_newlines가 True일 때, 클래스는 locale.getpreferredencoding() 대신 인코딩 locale.getpreferredencoding(False)를 사용합니다. 이 변경에 대한 자세한 내용은 io.TextIOWrapper 클래스를 참조하십시오.

참고

shell=True를 사용하기 전에 보안 고려 사항 섹션을 읽으십시오.

이러한 옵션들은, 다른 모든 옵션과 함께, Popen 생성자 설명서에 더 자세히 설명되어 있습니다.

Popen 생성자

이 모듈에서 하부 프로세스 생성과 관리는 Popen 클래스에 의해 처리됩니다. 개발자가 편의 함수가 다루지 않는 덜 일반적인 사례를 처리할 수 있도록 큰 유연성을 제공합니다.

class subprocess.Popen(args, bufsize=-1, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=True, shell=False, cwd=None, env=None, universal_newlines=None, startupinfo=None, creationflags=0, restore_signals=True, start_new_session=False, pass_fds=(), *, group=None, extra_groups=None, user=None, umask=-1, encoding=None, errors=None, text=None, pipesize=-1, process_group=None)

Execute a child program in a new process. On POSIX, the class uses os.execvpe()-like behavior to execute the child program. On Windows, the class uses the Windows CreateProcess() function. The arguments to Popen are as follows.

args는 프로그램 인자의 시퀀스이거나 그렇지 않으면 단일한 문자열이나 경로류 객체여야 합니다. 기본적으로, args가 시퀀스이면 실행할 프로그램은 args의 첫 번째 항목입니다. args가 문자열이면, 해석은 플랫폼에 따라 다르며 아래에 설명되어 있습니다. 기본 동작과의 추가 차이점에 관해서는 shell과 executable 인자를 참조하십시오. 별도의 언급이 없는 한, args를 시퀀스로 전달하는 것이 좋습니다.

경고

For maximum reliability, use a fully qualified path for the executable. To search for an unqualified name on PATH, use shutil.which(). On all platforms, passing sys.executable is the recommended way to launch the current Python interpreter again, and use the -m command-line format to launch an installed module.

Resolving the path of executable (or the first item of args) is platform dependent. For POSIX, see os.execvpe(), and note that when resolving or searching for the executable path, cwd overrides the current working directory and env can override the PATH environment variable. For Windows, see the documentation of the lpApplicationName and lpCommandLine parameters of WinAPI CreateProcess, and note that when resolving or searching for the executable path with shell=False, cwd does not override the current working directory and env cannot override the PATH environment variable. Using a full path avoids all of these variations.

시퀀스로 외부 프로그램에 어떤 인자를 전달하는 예는 다음과 같습니다:

Popen(["/usr/bin/git", "commit", "-m", "Fixes a bug."])

POSIX에서, args가 문자열이면, 문자열은 실행할 프로그램의 이름이나 경로로 해석됩니다. 그러나, 이것은 프로그램에 인자를 전달하지 않을 때만 수행할 수 있습니다.

참고

특히 복잡한 경우에, 셸 명령을 인자의 시퀀스로 나누는 방법이 명확하지 않을 수 있습니다. shlex.split()는 args의 올바른 토큰화를 결정하는 방법을 보여줄 수 있습니다:

>>> import shlex, subprocess
>>> command_line = input()
/bin/vikings -input eggs.txt -output "spam spam.txt" -cmd "echo '$MONEY'"
>>> args = shlex.split(command_line)
>>> print(args)
['/bin/vikings', '-input', 'eggs.txt', '-output', 'spam spam.txt', '-cmd', "echo '$MONEY'"]
>>> p = subprocess.Popen(args) # Success!

특히 셸에서 공백으로 구분된 옵션(가령 -input)과 인자(가령 eggs.txt)는 별도의 리스트 요소로 들어가지만, 셸에서 사용될 때 인용(quoting)이나 역 슬래시 이스케이프가 필요한 인자(가령 스페이스가 포함된 파일명이나 위에 표시된 echo 명령)는 단일 리스트 요소임에 유의하십시오.

윈도우에서, args가 시퀀스이면, 윈도우에서 인자 시퀀스를 문자열로 변환하기에 설명된 방식으로 문자열로 변환됩니다. 하부 CreateProcess()가 문자열에서 작동하기 때문입니다.

버전 3.6에서 변경: POSIX에서, args 매개 변수는 shell이 False이면 경로류 객체나 경로류 객체를 포함하는 시퀀스를 받아들입니다.

버전 3.8에서 변경: 윈도우에서, args 매개 변수는 shell이 False이면 경로류 객체나 바이트열과 경로류 객체를 포함하는 시퀀스를 받아들입니다.

shell 인자(기본값은 False)는 셸을 실행할 프로그램으로 사용할지를 지정합니다. shell이 True이면, args를 시퀀스가 아닌 문자열로 전달하는 것이 좋습니다.

POSIX에서 shell=True일 때, 셸의 기본값은 /bin/sh입니다. args가 문자열이면, 문자열은 셸을 통해 실행할 명령을 지정합니다. 이것은 문자열이 프롬프트에서 입력할 때와 똑같이 포맷되어야 한다는 것을 의미합니다. 예를 들어, 스페이스가 포함된 파일명을 인용하거나 역 슬래시 이스케이핑 하는 것을 포함합니다. args가 시퀀스이면, 첫 번째 항목이 명령 문자열을 지정하고, 추가 항목은 셸 자체에 대한 추가 인자로 처리됩니다. 즉, Popen은 다음과 동등한 것을 수행합니다:

Popen(['/bin/sh', '-c', args[0], args[1], ...])

윈도우에서 shell=True일 때, COMSPEC 환경 변수는 기본 셸을 지정합니다. 윈도우에서 shell=True를 지정해야 하는 유일한 경우는 실행하려는 명령이 셸에 내장되었을 때입니다 (예를 들어 dir이나 copy). 배치 파일이나 콘솔 기반 실행 파일을 실행하기 위해 shell=True가 필요하지 않습니다.

참고

shell=True를 사용하기 전에 보안 고려 사항 섹션을 읽으십시오.

bufsize는 stdin/stdout/stderr 파이프 파일 객체를 만들 때 open() 함수에 해당 인자로 제공됩니다:

0 means unbuffered (read and write are one system call and can return short)

1 means line buffered (only usable if text=True or universal_newlines=True)

다른 양수 값은 대략 그 크기의 버퍼를 사용함을 의미합니다.

음의 bufsize(기본값)는 시스템 기본값 io.DEFAULT_BUFFER_SIZE가 사용됨을 의미합니다.

버전 3.3.1에서 변경: bufsize now defaults to -1 to enable buffering by default to match the behavior that most code expects. In versions prior to Python 3.2.4 and 3.3.1 it incorrectly defaulted to 0 which was unbuffered and allowed short reads. This was unintentional and did not match the behavior of Python 2 as most code expected.

executable 인자는 실행할 대체 프로그램을 지정합니다. 거의 필요하지 않습니다. shell=False일 때, executable은 args에 의해 지정된 프로그램을 대체합니다. 그러나, 원래 args는 여전히 프로그램으로 전달됩니다. 대부분의 프로그램은 args에 의해 지정된 프로그램을 명령 이름으로 취급합니다, 그래서 실제로 실행되는 프로그램과 다를 수 있습니다. POSIX에서, args 이름은 ps와 같은 유틸리티에서 실행 파일의 표시 이름이 됩니다. shell=True이면, POSIX에서 executable 인자는 기본 /bin/sh의 대체 셸을 지정합니다.

버전 3.6에서 변경: POSIX에서 executable 매개 변수는 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서 executable 매개 변수는 바이트열과 경로류 객체를 받아들입니다.

버전 3.12에서 변경: Changed Windows shell search order for shell=True. The current directory and %PATH% are replaced with %COMSPEC% and %SystemRoot%\System32\cmd.exe. As a result, dropping a malicious program named cmd.exe into a current directory no longer works.

stdin, stdout and stderr specify the executed program’s standard input, standard output and standard error file handles, respectively. Valid values are None, PIPE, DEVNULL, an existing file descriptor (a positive integer), and an existing file object with a valid file descriptor. With the default settings of None, no redirection will occur. PIPE indicates that a new pipe to the child should be created. DEVNULL indicates that the special file os.devnull will be used. Additionally, stderr can be STDOUT, which indicates that the stderr data from the applications should be captured into the same file handle as for stdout.

preexec_fn이 콜러블 객체로 설정되면, 이 객체는 자식 프로세스가 실행되기 직전에 자식 프로세스에서 호출됩니다. (POSIX 전용)

경고

The preexec_fn parameter is NOT SAFE to use in the presence of threads in your application. The child process could deadlock before exec is called.

참고

If you need to modify the environment for the child use the env parameter rather than doing it in a preexec_fn. The start_new_session and process_group parameters should take the place of code using preexec_fn to call os.setsid() or os.setpgid() in the child.

버전 3.8에서 변경: 서브 인터프리터에서 preexec_fn 매개 변수가 더는 지원되지 않습니다. 서브 인터프리터에서 매개 변수를 사용하면 RuntimeError가 발생합니다. 새로운 제약 사항은 mod_wsgi, uWSGI 및 기타 내장(embedded) 환경에 배치된 응용 프로그램에 영향을 줄 수 있습니다.

If close_fds is true, all file descriptors except 0, 1 and 2 will be closed before the child process is executed. Otherwise when close_fds is false, file descriptors obey their inheritable flag as described in 파일 기술자의 상속.

윈도우에서, close_fds가 참이면 STARTUPINFO.lpAttributeList의 handle_list 요소에 명시적으로 전달되거나 표준 핸들 리디렉션에 의하지 않는 한 자식 프로세스가 핸들을 상속하지 않습니다.

버전 3.2에서 변경: close_fds의 기본값은 False에서 위에서 설명한 것으로 변경되었습니다.

버전 3.7에서 변경: 윈도우에서 표준 핸들을 리디렉션 할 때 close_fds의 기본값이 False에서 True로 변경되었습니다. 이제 표준 핸들을 리디렉션 할 때 close_fds를 True로 설정할 수 있습니다.

pass_fds는 부모와 자식 사이에 열려있는 파일 기술자의 선택적 시퀀스입니다. pass_fds를 제공하면 close_fds가 True가 됩니다. (POSIX 전용)

버전 3.2에서 변경: pass_fds 매개 변수가 추가되었습니다.

If cwd is not None, the function changes the working directory to cwd before executing the child. cwd can be a string, bytes or path-like object. On POSIX, the function looks for executable (or for the first item in args) relative to cwd if the executable path is a relative path.

버전 3.6에서 변경: POSIX에서 cwd 매개 변수는 경로류 객체를 받아들입니다.

버전 3.7에서 변경: 윈도우에서 cwd 매개 변수는 경로류 객체를 받아들입니다.

버전 3.8에서 변경: 윈도우에서 cwd 매개 변수는 바이트열 객체를 받아들입니다.

restore_signals가 참(기본값)이면 파이썬이 SIG_IGN으로 설정한 모든 시그널은 실행 전에 자식 프로세스에서 SIG_DFL로 복원됩니다. 현재 여기에는 SIGPIPE, SIGXFZ 및 SIGXFSZ 시그널이 포함됩니다. (POSIX 전용)

버전 3.2에서 변경: restore_signals가 추가되었습니다.

If start_new_session is true the setsid() system call will be made in the child process prior to the execution of the subprocess.

Availability: POSIX

버전 3.2에서 변경: start_new_session이 추가되었습니다.

If process_group is a non-negative integer, the setpgid(0, value) system call will be made in the child process prior to the execution of the subprocess.

Availability: POSIX

버전 3.11에서 변경: process_group was added.

If group is not None, the setregid() system call will be made in the child process prior to the execution of the subprocess. If the provided value is a string, it will be looked up via grp.getgrnam() and the value in gr_gid will be used. If the value is an integer, it will be passed verbatim. (POSIX only)

Availability: POSIX

Added in version 3.9.

If extra_groups is not None, the setgroups() system call will be made in the child process prior to the execution of the subprocess. Strings provided in extra_groups will be looked up via grp.getgrnam() and the values in gr_gid will be used. Integer values will be passed verbatim. (POSIX only)

Availability: POSIX

Added in version 3.9.

If user is not None, the setreuid() system call will be made in the child process prior to the execution of the subprocess. If the provided value is a string, it will be looked up via pwd.getpwnam() and the value in pw_uid will be used. If the value is an integer, it will be passed verbatim. (POSIX only)

Availability: POSIX

Added in version 3.9.

umask가 음이 아니면, 서브 프로세스를 실행하기 전에 자식 프로세스에서 umask() 시스템 호출이 수행됩니다.

Availability: POSIX

Added in version 3.9.

If env is not None, it must be a mapping that defines the environment variables for the new process; these are used instead of the default behavior of inheriting the current process’ environment. This mapping can be str to str on any platform or bytes to bytes on POSIX platforms much like os.environ or os.environb.

참고

지정되면, env는 프로그램 실행에 필요한 모든 변수를 제공해야 합니다. 윈도우에서, side-by-side assembly [https://en.wikipedia.org/wiki/Side-by-Side_Assembly]를 실행하려면 지정된 env에 유효한 SystemRoot가 반드시 포함되어야 합니다.

If encoding or errors are specified, or text is true, the file objects stdin, stdout and stderr are opened in text mode with the specified encoding and errors, as described above in 자주 사용되는 인자. The universal_newlines argument is equivalent to text and is provided for backwards compatibility. By default, file objects are opened in binary mode.

Added in version 3.6: encoding과 errors가 추가되었습니다.

Added in version 3.7: text가 universal_newlines의 더 가독성 있는 별칭으로 추가되었습니다.

If given, startupinfo will be a STARTUPINFO object, which is passed to the underlying CreateProcess function.

If given, creationflags, can be one or more of the following flags:

CREATE_NEW_CONSOLE

CREATE_NEW_PROCESS_GROUP

ABOVE_NORMAL_PRIORITY_CLASS

BELOW_NORMAL_PRIORITY_CLASS

HIGH_PRIORITY_CLASS

IDLE_PRIORITY_CLASS

NORMAL_PRIORITY_CLASS

REALTIME_PRIORITY_CLASS

CREATE_NO_WINDOW

DETACHED_PROCESS

CREATE_DEFAULT_ERROR_MODE

CREATE_BREAKAWAY_FROM_JOB

pipesize can be used to change the size of the pipe when PIPE is used for stdin, stdout or stderr. The size of the pipe is only changed on platforms that support this (only Linux at this time of writing). Other platforms will ignore this parameter.

버전 3.10에서 변경: Added the pipesize parameter.

Popen 객체는 with 문을 통해 컨텍스트 관리자로 지원됩니다; 빠져나갈 때, 표준 파일 기술자가 닫히고 프로세스를 기다립니다.

with Popen(["ifconfig"], stdout=PIPE) as proc:
    log.write(proc.stdout.read())

Popen과 이 모듈에서 이를 사용하는 다른 함수는 인자 executable, args, cwd 및 env로 감사 이벤트 subprocess.Popen을 발생시킵니다. args의 값은 플랫폼에 따라 단일 문자열이나 문자열 리스트일 수 있습니다.

버전 3.2에서 변경: 컨텍스트 관리자 지원이 추가되었습니다.

버전 3.6에서 변경: 자식 프로세스가 여전히 실행 중이면 이제 Popen 파괴자(destructor)가 ResourceWarning 경고를 발생시킵니다.

버전 3.8에서 변경: Popen은 성능 향상을 위해 때에 따라 os.posix_spawn()을 사용할 수 있습니다. 리눅스용 윈도우 서브 시스템(Windows Subsystem for Linux)과 QEMU 사용자 에뮬레이션(QEMU User Emulation)에서, os.posix_spawn()을 사용하는 Popen 생성자는 더는 프로그램 누락과 같은 에러에 대한 예외를 발생시키지 않지만, 자식 프로세스는 0이 아닌 returncode로 실패합니다.

예외

새 프로그램이 실행을 시작하기 전에 자식 프로세스에서 발생한 예외는 부모에서 다시 발생합니다.

The most common exception raised is OSError. This occurs, for example, when trying to execute a non-existent file. Applications should prepare for OSError exceptions. Note that, when shell=True, OSError will be raised by the child only if the selected shell itself was not found. To determine if the shell failed to find the requested application, it is necessary to check the return code or output from the subprocess.

Popen이 유효하지 않은 인자로 호출되면 ValueError가 발생합니다.

호출된 프로세스가 0이 아닌 반환 코드를 반환하면 check_call()과 check_output()은 CalledProcessError를 발생시킵니다.

All of the functions and methods that accept a timeout parameter, such as run() and Popen.communicate() will raise TimeoutExpired if the timeout expires before the process exits.

이 모듈에 정의된 예외는 모두 SubprocessError를 상속합니다.

Added in version 3.3: SubprocessError 베이스 클래스가 추가되었습니다.

보안 고려 사항

Unlike some other popen functions, this library will not implicitly choose to call a system shell. This means that all characters, including shell metacharacters, can safely be passed to child processes. If the shell is invoked explicitly, via shell=True, it is the application’s responsibility to ensure that all whitespace and metacharacters are quoted appropriately to avoid shell injection [https://en.wikipedia.org/wiki/Shell_injection#Shell_injection] vulnerabilities. On some platforms, it is possible to use shlex.quote() for this escaping.

On Windows, batch files (*.bat or *.cmd) may be launched by the operating system in a system shell regardless of the arguments passed to this library. This could result in arguments being parsed according to shell rules, but without any escaping added by Python. If you are intentionally launching a batch file with arguments from untrusted sources, consider passing shell=True to allow Python to escape special characters. See gh-114539 [https://github.com/python/cpython/issues/114539] for additional discussion.

Popen 객체

Popen 클래스의 인스턴스에는 다음과 같은 메서드가 있습니다:

Popen.poll()

자식 프로세스가 종료되었는지 확인합니다. returncode 어트리뷰트를 설정하고 반환합니다. 그렇지 않으면, None을 반환합니다.

Popen.wait(timeout=None)

자식 프로세스가 종료될 때까지 기다립니다. returncode 어트리뷰트를 설정하고 반환합니다.

timeout 초 후에 프로세스가 종료되지 않으면, TimeoutExpired 예외를 발생시킵니다. 이 예외를 잡고 다시 기다리는 것은 안전합니다.

참고

이는 stdout=PIPE나 stderr=PIPE를 사용하고 자식 프로세스가 파이프에 너무 많은 출력을 보내서 OS 파이프 버퍼가 더 많은 데이터를 받아들일 때까지 기다리느라 블록하면 교착 상태에 빠집니다. 파이프를 사용할 때 이를 피하려면 Popen.communicate()를 사용하십시오.

참고

When the timeout parameter is not None, then (on POSIX) the function is implemented using a busy loop (non-blocking call and short sleeps). Use the asyncio module for an asynchronous wait: see asyncio.create_subprocess_exec.

버전 3.3에서 변경: timeout이 추가되었습니다.

Popen.communicate(input=None, timeout=None)

프로세스와 상호 작용합니다: stdin에 데이터를 보냅니다. 파일 끝에 도달할 때까지 stdout과 stderr에서 데이터를 읽습니다. 프로세스가 종료될 때까지 기다리고, returncode 어트리뷰트를 설정합니다. 선택적 input 인자는 자식 프로세스로 전송될 데이터이거나, 자식으로 데이터를 보내지 않으면 None이어야 합니다. 스트림이 텍스트 모드로 열렸으면, input은 문자열이어야 합니다. 그렇지 않으면, 바이트열이어야 합니다.

communicate()는 튜플 (stdout_data, stderr_data)를 반환합니다. 스트림이 텍스트 모드로 열렸으면 데이터는 문자열이 됩니다. 그렇지 않으면 바이트열입니다.

프로세스의 stdin으로 데이터를 보내려면, stdin=PIPE를 사용하여 Popen 객체를 만들어야 함에 유의하십시오. 마찬가지로, 결과 튜플에서 None 이외의 것을 얻으려면, stdout=PIPE 및/또는 stderr=PIPE도 제공해야 합니다.

timeout 초 후에 프로세스가 종료되지 않으면, TimeoutExpired 예외가 발생합니다. 이 예외를 잡고 통신을 다시 시도해도 출력이 손실되지 않습니다.

시간제한이 만료되면 자식 프로세스를 죽이지 않습니다, 올바르게 정리하려면 제대로 작동하는 응용 프로그램은 자식 프로세스를 죽이고 통신을 완료해야 합니다:

proc = subprocess.Popen(...)
try:
    outs, errs = proc.communicate(timeout=15)
except TimeoutExpired:
    proc.kill()
    outs, errs = proc.communicate()

참고

읽은 데이터는 메모리에 버퍼링 되므로, 데이터 크기가 크거나 무제한이면 이 메서드를 사용하지 마십시오.

버전 3.3에서 변경: timeout이 추가되었습니다.

Popen.send_signal(signal)

시그널 signal을 자식에게 보냅니다.

프로세스가 완료되었으면 아무것도 하지 않습니다.

참고

On Windows, SIGTERM is an alias for terminate(). CTRL_C_EVENT and CTRL_BREAK_EVENT can be sent to processes started with a creationflags parameter which includes CREATE_NEW_PROCESS_GROUP.

Popen.terminate()

Stop the child. On POSIX OSs the method sends SIGTERM to the child. On Windows the Win32 API function TerminateProcess() is called to stop the child.

Popen.kill()

자식을 죽입니다. POSIX OS에서 이 함수는 SIGKILL을 자식에게 보냅니다. 윈도우에서 kill()은 terminate()의 별칭입니다.

The following attributes are also set by the class for you to access. Reassigning them to new values is unsupported:

Popen.args

Popen으로 전달된 args 인자 – 프로그램 인자의 시퀀스거나 단일 문자열.

Added in version 3.3.

Popen.stdin

If the stdin argument was PIPE, this attribute is a writeable stream object as returned by open(). If the encoding or errors arguments were specified or the text or universal_newlines argument was True, the stream is a text stream, otherwise it is a byte stream. If the stdin argument was not PIPE, this attribute is None.

Popen.stdout

If the stdout argument was PIPE, this attribute is a readable stream object as returned by open(). Reading from the stream provides output from the child process. If the encoding or errors arguments were specified or the text or universal_newlines argument was True, the stream is a text stream, otherwise it is a byte stream. If the stdout argument was not PIPE, this attribute is None.

Popen.stderr

If the stderr argument was PIPE, this attribute is a readable stream object as returned by open(). Reading from the stream provides error output from the child process. If the encoding or errors arguments were specified or the text or universal_newlines argument was True, the stream is a text stream, otherwise it is a byte stream. If the stderr argument was not PIPE, this attribute is None.

경고

다른 OS 파이프 버퍼가 차고 자식 프로세스를 블로킹하는 것으로 인한 교착 상태를 피하려면 .stdin.write, .stdout.read 또는 .stderr.read 대신 communicate()를 사용하십시오.

Popen.pid

자식 프로세스의 프로세스 ID

shell 인자를 True로 설정하면, 이것은 생성된 셸의 프로세스 ID입니다.

Popen.returncode

The child return code. Initially None, returncode is set by a call to the poll(), wait(), or communicate() methods if they detect that the process has terminated.

A None value indicates that the process hadn’t yet terminated at the time of the last method call.

음수 값 -N은 자식이 시그널 N에 의해 종료되었음을 나타냅니다 (POSIX 전용).

윈도우 Popen 도우미

STARTUPINFO 클래스와 다음 상수는 윈도우에서만 사용 가능합니다.

class subprocess.STARTUPINFO(*, dwFlags=0, hStdInput=None, hStdOutput=None, hStdError=None, wShowWindow=0, lpAttributeList=None)

윈도우 STARTUPINFO [https://msdn.microsoft.com/en-us/library/ms686331(v=vs.85).aspx] 구조체의 부분적인 지원이 Popen 생성에 사용됩니다. 다음 어트리뷰트는 키워드 전용 인자로 전달하여 설정할 수 있습니다.

버전 3.7에서 변경: 키워드 전용 인자 지원이 추가되었습니다.

dwFlags

프로세스가 창을 만들 때 특정 STARTUPINFO 어트리뷰트가 사용되는지를 결정하는 비트 필드.

si = subprocess.STARTUPINFO()
si.dwFlags = subprocess.STARTF_USESTDHANDLES | subprocess.STARTF_USESHOWWINDOW

hStdInput

dwFlags가 STARTF_USESTDHANDLES를 지정하면, 이 어트리뷰트는 프로세스의 표준 입력 핸들입니다. STARTF_USESTDHANDLES가 지정되지 않으면, 표준 입력의 기본값은 키보드 버퍼입니다.

hStdOutput

dwFlags가 STARTF_USESTDHANDLES를 지정하면, 이 어트리뷰트는 프로세스의 표준 출력 핸들입니다. 그렇지 않으면, 이 어트리뷰트가 무시되고 표준 출력의 기본값은 콘솔 창의 버퍼입니다.

hStdError

dwFlags가 STARTF_USESTDHANDLES를 지정하면, 이 어트리뷰트는 프로세스의 표준 에러 핸들입니다. 그렇지 않으면, 이 어트리뷰트는 무시되고 표준 에러의 기본값은 콘솔 창의 버퍼입니다.

wShowWindow

dwFlags가 STARTF_USESHOWWINDOW를 지정하면, 이 어트리뷰트는 SW_SHOWDEFAULT를 제외하고 ShowWindow [https://msdn.microsoft.com/en-us/library/ms633548(v=vs.85).aspx] 함수의 nCmdShow 매개 변수에 지정할 수 있는 값 중 어느 것이건 될 수 있습니다. 그렇지 않으면, 이 어트리뷰트는 무시됩니다.

이 어트리뷰트에 SW_HIDE가 제공됩니다. Popen이 shell=True와 함께 호출될 때 사용됩니다.

lpAttributeList

STARTUPINFOEX에 제공된 대로 프로세스 생성을 위한 추가 어트리뷰트 딕셔너리, UpdateProcThreadAttribute [https://msdn.microsoft.com/en-us/library/windows/desktop/ms686880(v=vs.85).aspx]를 참조하십시오.

지원되는 어트리뷰트:

handle_list

상속될 핸들의 시퀀스. 비어 있지 않으면 close_fds는 참이어야 합니다.

Popen 생성자에 전달될 때 os.set_handle_inheritable()로 핸들을 일시적으로 상속할 수 있도록 만들어야 합니다, 그렇지 않으면 윈도우 에러 ERROR_INVALID_PARAMETER (87) 로 OSError가 발생합니다.

경고

다중 스레드 프로세스에서, 이 기능을 os.system()과 같은 모든 핸들을 상속하는 다른 프로세스 생성 함수에 대한 동시 호출과 결합할 때 상속 가능으로 표시된 핸들의 누수를 피하도록 주의하십시오. 이것은 일시적으로 상속 가능한 핸들을 만드는 표준 핸들 리디렉션에도 적용됩니다.

Added in version 3.7.

윈도우 상수

subprocess 모듈은 다음 상수를 노출합니다.

subprocess.STD_INPUT_HANDLE

표준 입력 장치. 처음에는, 콘솔 입력 버퍼입니다, CONIN$.

subprocess.STD_OUTPUT_HANDLE

표준 출력 장치. 처음에는, 활성 콘솔 화면 버퍼입니다, CONOUT$.

subprocess.STD_ERROR_HANDLE

표준 에러 장치. 처음에는, 활성 콘솔 화면 버퍼입니다, CONOUT$.

subprocess.SW_HIDE

창을 숨깁니다. 다른 창이 활성화됩니다.

subprocess.STARTF_USESTDHANDLES

STARTUPINFO.hStdInput, STARTUPINFO.hStdOutput 및 STARTUPINFO.hStdError 어트리뷰트에 추가 정보가 포함되었음을 지정합니다.

subprocess.STARTF_USESHOWWINDOW

STARTUPINFO.wShowWindow 어트리뷰트에 추가 정보가 포함되었음을 지정합니다.

subprocess.STARTF_FORCEONFEEDBACK

A STARTUPINFO.dwFlags parameter to specify that the Working in Background mouse cursor will be displayed while a process is launching. This is the default behavior for GUI processes.

Added in version 3.13.

subprocess.STARTF_FORCEOFFFEEDBACK

A STARTUPINFO.dwFlags parameter to specify that the mouse cursor will not be changed when launching a process.

Added in version 3.13.

subprocess.CREATE_NEW_CONSOLE

새로운 프로세스는 부모의 콘솔을 상속(기본값)하는 대신 새로운 콘솔을 갖습니다.

subprocess.CREATE_NEW_PROCESS_GROUP

새 프로세스 그룹이 만들어지도록 지정하는 Popen creationflags 매개 변수. 이 플래그는 서브 프로세스에 os.kill()을 사용하기 위해 필요합니다.

CREATE_NEW_CONSOLE이 지정되면 이 플래그는 무시됩니다.

subprocess.ABOVE_NORMAL_PRIORITY_CLASS

새 프로세스가 평균 우선순위를 초과하도록 지정하는 Popen creationflags 매개 변수.

Added in version 3.7.

subprocess.BELOW_NORMAL_PRIORITY_CLASS

새 프로세스가 평균 우선순위보다 낮도록 지정하는 Popen creationflags 매개 변수.

Added in version 3.7.

subprocess.HIGH_PRIORITY_CLASS

새 프로세스가 높은 우선순위를 갖도록 지정하는 Popen creationflags 매개 변수입니다.

Added in version 3.7.

subprocess.IDLE_PRIORITY_CLASS

새 프로세스가 유휴 (가장 낮은) 우선순위를 갖도록 지정하는 Popen creationflags 매개 변수.

Added in version 3.7.

subprocess.NORMAL_PRIORITY_CLASS

A Popen creationflags parameter to specify that a new process will have a normal priority. (default)

Added in version 3.7.

subprocess.REALTIME_PRIORITY_CLASS

새 프로세스가 실시간 우선순위를 갖도록 지정하는 Popen creationflags 매개 변수. REALTIME_PRIORITY_CLASS를 사용하면 마우스 입력, 키보드 입력 및 백그라운드 디스크 플러시를 관리하는 시스템 스레드가 중단되므로 거의 사용하지 않아야 합니다. 이 클래스는 하드웨어와 직접 “대화”하거나 중단이 제한되어야 하는 짧은 작업을 수행하는 응용 프로그램에 적합할 수 있습니다.

Added in version 3.7.

subprocess.CREATE_NO_WINDOW

새 프로세스가 창을 만들지 않도록 지정하는 Popen creationflags 매개 변수.

Added in version 3.7.

subprocess.DETACHED_PROCESS

새 프로세스가 부모의 콘솔을 상속하지 않도록 지정하는 Popen creationflags 매개 변수. 이 값은 CREATE_NEW_CONSOLE과 함께 사용할 수 없습니다.

Added in version 3.7.

subprocess.CREATE_DEFAULT_ERROR_MODE

새 프로세스가 호출하는 프로세스의 에러 모드를 상속하지 않도록 지정하는 Popen creationflags 매개 변수. 대신, 새 프로세스는 기본 에러 모드를 갖습니다. 이 기능은 하드(hard) 에러가 비활성화된 상태로 실행되는 다중 스레드 셸 응용 프로그램에 특히 유용합니다.

Added in version 3.7.

subprocess.CREATE_BREAKAWAY_FROM_JOB

새 프로세스가 잡(job)과 연관되지 않도록 지정하는 Popen creationflags 매개 변수.

Added in version 3.7.

오래된 고수준 API

파이썬 3.5 이전에는, 이 세 가지 함수가 subprocess에 대한 고수준 API로 구성되었습니다. 이제 많은 경우에 run()을 사용할 수 있지만, 많은 기존 코드가 이러한 함수를 호출합니다.

subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False, cwd=None, timeout=None, **other_popen_kwargs)

args로 기술된 명령을 실행합니다. 명령이 완료될 때까지 기다린 후 returncode 어트리뷰트를 반환합니다.

stdout이나 stderr을 캡처해야 하는 코드는 대신 run()을 사용해야 합니다:

run(...).returncode

stdout이나 stderr을 억제하려면, DEVNULL 값을 제공하십시오.

위에 표시된 인자는 단지 몇 가지 일반적인 인자입니다. 전체 함수 서명은 Popen 생성자의 서명과 같습니다 - 이 함수는 timeout 이외의 모든 제공된 인자를 해당 인터페이스로 직접 전달합니다.

참고

이 함수에 stdout=PIPE나 stderr=PIPE를 사용하지 마십시오. 파이프를 읽지 않기 때문에 자식 프로세스가 OS 파이프 버퍼를 가득 채우기 충분한 출력을 생성하면 자식 프로세스가 블록 됩니다.

버전 3.3에서 변경: timeout이 추가되었습니다.

버전 3.12에서 변경: Changed Windows shell search order for shell=True. The current directory and %PATH% are replaced with %COMSPEC% and %SystemRoot%\System32\cmd.exe. As a result, dropping a malicious program named cmd.exe into a current directory no longer works.

subprocess.check_call(args, *, stdin=None, stdout=None, stderr=None, shell=False, cwd=None, timeout=None, **other_popen_kwargs)

Run command with arguments. Wait for command to complete. If the return code was zero then return, otherwise raise CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute. If check_call() was unable to start the process it will propagate the exception that was raised.

stdout이나 stderr을 캡처해야 하는 코드는 대신 run()을 사용해야 합니다:

run(..., check=True)

stdout이나 stderr을 억제하려면, DEVNULL 값을 제공하십시오.

위에 표시된 인자는 단지 몇 가지 일반적인 인자입니다. 전체 함수 서명은 Popen 생성자의 서명과 같습니다 - 이 함수는 timeout 이외의 모든 제공된 인자를 해당 인터페이스로 직접 전달합니다.

참고

이 함수에 stdout=PIPE나 stderr=PIPE를 사용하지 마십시오. 파이프를 읽지 않기 때문에 자식 프로세스가 OS 파이프 버퍼를 가득 채우기 충분한 출력을 생성하면 자식 프로세스가 블록 됩니다.

버전 3.3에서 변경: timeout이 추가되었습니다.

버전 3.12에서 변경: Changed Windows shell search order for shell=True. The current directory and %PATH% are replaced with %COMSPEC% and %SystemRoot%\System32\cmd.exe. As a result, dropping a malicious program named cmd.exe into a current directory no longer works.

subprocess.check_output(args, *, stdin=None, stderr=None, shell=False, cwd=None, encoding=None, errors=None, universal_newlines=None, timeout=None, text=None, **other_popen_kwargs)

인자로 명령을 실행하고 출력을 반환합니다.

반환 코드가 0이 아니면 CalledProcessError 가 발생합니다. CalledProcessError 객체는 returncode 어트리뷰트에 반환 코드가 있고 output 어트리뷰트에 출력이 있습니다.

이것은 다음과 동등합니다:

run(..., check=True, stdout=PIPE).stdout

위에 표시된 인자는 단지 몇 가지 일반적인 인자입니다. 전체 함수 서명은 run()의 서명과 거의 같습니다 - 대부분의 인자는 해당 인터페이스로 직접 전달됩니다. run() 동작과 비교할 때 한가지 API 편차가 있습니다: input=None을 전달하면 부모의 표준 입력 파일 핸들을 사용하는 대신 input=b'' (또는 다른 인자에 따라 input='') 와 같게 동작합니다.

기본적으로, 이 함수는 데이터를 인코딩된 바이트열로 반환합니다. 출력 데이터의 실제 인코딩은 호출되는 명령에 따라 달라질 수 있어서, 텍스트로의 디코딩은 종종 응용 프로그램 수준에서 처리해야 합니다.

자주 사용되는 인자와 run()에 설명된 대로 text, encoding, errors 또는 universal_newlines를 True로 설정하면 이 동작을 재정의할 수 있습니다.

결과에서 표준 에러도 캡처하려면 stderr=subprocess.STDOUT을 사용하십시오:

>>> subprocess.check_output(
...     "ls non_existent_file; exit 0",
...     stderr=subprocess.STDOUT,
...     shell=True)
'ls: non_existent_file: No such file or directory\n'

Added in version 3.1.

버전 3.3에서 변경: timeout이 추가되었습니다.

버전 3.4에서 변경: input 키워드 인자에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: encoding과 errors가 추가되었습니다. 자세한 내용은 run()을 참조하십시오.

Added in version 3.7: text가 universal_newlines의 더 가독성 있는 별칭으로 추가되었습니다.

버전 3.12에서 변경: Changed Windows shell search order for shell=True. The current directory and %PATH% are replaced with %COMSPEC% and %SystemRoot%\System32\cmd.exe. As a result, dropping a malicious program named cmd.exe into a current directory no longer works.

이전 함수를 subprocess 모듈로 교체하기

이 섹션에서, “a는 b가 됩니다”는 b가 a의 대체로 사용될 수 있음을 의미합니다.

참고

이 섹션의 모든 “a” 함수는 실행되는 프로그램을 찾을 수 없으면 (다소간) 조용히 실패합니다; “b” 대체는 대신 OSError를 발생시킵니다.

또한, 요청된 연산이 0이 아닌 반환 코드를 생성하면 check_output()을 사용한 대체는 CalledProcessError로 실패합니다. 출력은 여전히 발생한 예외의 output 어트리뷰트로 사용 가능합니다.

다음 예에서는, 관련 함수들을 subprocess 모듈에서 이미 임포트 했다고 가정합니다.

/bin/sh 셸 명령 치환 교체하기

output=$(mycmd myarg)

는 다음처럼 됩니다:

output = check_output(["mycmd", "myarg"])

셸 파이프라인 교체하기

output=$(dmesg | grep hda)

는 다음처럼 됩니다:

p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
p1.stdout.close()  # Allow p1 to receive a SIGPIPE if p2 exits.
output = p2.communicate()[0]

p2가 p1보다 먼저 종료될 때 p1이 SIGPIPE를 수신하려면 p2를 시작한 후 p1.stdout.close() 호출이 중요합니다.

또는, 신뢰할 수 있는 입력의 경우, 셸의 자체 파이프라인 지원을 계속 사용할 수 있습니다:

output=$(dmesg | grep hda)

는 다음처럼 됩니다:

output = check_output("dmesg | grep hda", shell=True)

os.system() 교체하기

sts = os.system("mycmd" + " myarg")
# becomes
retcode = call("mycmd" + " myarg", shell=True)

노트:

보통 셸을 통해 프로그램을 호출할 필요는 없습니다.

The call() return value is encoded differently to that of os.system().

The os.system() function ignores SIGINT and SIGQUIT signals while the command is running, but the caller must do this separately when using the subprocess module.

더욱 현실적인 예는 다음과 같습니다:

try:
    retcode = call("mycmd" + " myarg", shell=True)
    if retcode < 0:
        print("Child was terminated by signal", -retcode, file=sys.stderr)
    else:
        print("Child returned", retcode, file=sys.stderr)
except OSError as e:
    print("Execution failed:", e, file=sys.stderr)

os.spawn 패밀리 교체하기

P_NOWAIT 예:

pid = os.spawnlp(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg")
==>
pid = Popen(["/bin/mycmd", "myarg"]).pid

P_WAIT 예:

retcode = os.spawnlp(os.P_WAIT, "/bin/mycmd", "mycmd", "myarg")
==>
retcode = call(["/bin/mycmd", "myarg"])

벡터 예:

os.spawnvp(os.P_NOWAIT, path, args)
==>
Popen([path] + args[1:])

환경 예:

os.spawnlpe(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg", env)
==>
Popen(["/bin/mycmd", "myarg"], env={"PATH": "/usr/bin"})

Replacing os.popen()

반환 코드 처리는 다음과 같이 번역됩니다:

pipe = os.popen(cmd, 'w')
...
rc = pipe.close()
if rc is not None and rc >> 8:
    print("There were some errors")
==>
process = Popen(cmd, stdin=PIPE)
...
process.stdin.close()
if process.wait() != 0:
    print("There were some errors")

레거시 셸 호출 함수

이 모듈은 2.x commands 모듈의 다음과 같은 레거시 함수도 제공합니다. 이러한 연산은 시스템 셸을 묵시적으로 호출하고 보안과 예외 처리 일관성과 관련하여 위에서 설명한 보증 중 어느 것도 이러한 함수에 유효하지 않습니다.

subprocess.getstatusoutput(cmd, *, encoding=None, errors=None)

셸에서 cmd를 실행한 후 (exitcode, output)을 반환합니다.

Execute the string cmd in a shell with Popen.check_output() and return a 2-tuple (exitcode, output). encoding and errors are used to decode output; see the notes on 자주 사용되는 인자 for more details.

후행 줄 바꿈이 출력에서 제거됩니다. 명령의 종료 코드는 서브 프로세스의 반환 코드로 해석될 수 있습니다. 예:

>>> subprocess.getstatusoutput('ls /bin/ls')
(0, '/bin/ls')
>>> subprocess.getstatusoutput('cat /bin/junk')
(1, 'cat: /bin/junk: No such file or directory')
>>> subprocess.getstatusoutput('/bin/junk')
(127, 'sh: /bin/junk: not found')
>>> subprocess.getstatusoutput('/bin/kill $$')
(-15, '')

Availability: Unix, Windows.

버전 3.3.4에서 변경: 윈도우 지원이 추가되었습니다.

이 함수는 이제 파이썬 3.3.3과 이전 버전에서와같이 (status, output) 대신 (exitcode, output) 을 반환합니다. exitcode는 returncode와 같은 값을 갖습니다.

버전 3.11에서 변경: Added the encoding and errors parameters.

subprocess.getoutput(cmd, *, encoding=None, errors=None)

셸에서 cmd를 실행한 출력(stdout과 stderr)을 반환합니다.

종료 코드를 무시하고 반환 값은 명령의 출력을 포함하는 문자열인 것을 제외하고, getstatusoutput() 과 유사합니다. 예:

>>> subprocess.getoutput('ls /bin/ls')
'/bin/ls'

Availability: Unix, Windows.

버전 3.3.4에서 변경: 윈도우 지원이 추가되었습니다

버전 3.11에서 변경: Added the encoding and errors parameters.

노트

윈도우에서 인자 시퀀스를 문자열로 변환하기

윈도우에서, args 시퀀스는 다음 규칙을 사용하여 구문 분석할 수 있는 문자열로 변환됩니다 (MS C 런타임에서 사용하는 규칙에 해당합니다):

인자는 스페이스나 탭인 공백으로 구분됩니다.

큰따옴표로 묶인 문자열은 포함된 공백과 관계없이 단일 인자로 해석됩니다. 인용된 문자열을 인자에 포함할 수 있습니다.

백 슬래시가 앞에 붙는 큰따옴표는 리터럴 큰따옴표로 해석됩니다.

역 슬래시는 큰따옴표 바로 앞에 오지 않는 한 문자 그대로 해석됩니다.

역 슬래시가 큰따옴표 바로 앞에 있으면, 모든 역 슬래시 쌍은 리터럴 역 슬래시로 해석됩니다. 역 슬래시 수가 홀수이면, 규칙 3에 설명된 대로 마지막 역 슬래시는 다음 큰따옴표를 이스케이프 합니다.

더 보기

shlex

명령 줄을 구문 분석하고 이스케이프 하는 함수를 제공하는 모듈.

Disable use of posix_spawn()

On Linux, subprocess defaults to using the vfork() system call internally when it is safe to do so rather than fork(). This greatly improves performance.

subprocess._USE_POSIX_SPAWN = False  # See CPython issue gh-NNNNNN.

It is safe to set this to false on any Python version. It will have no effect on older or newer versions where unsupported. Do not assume the attribute is available to read. Despite the name, a true value does not indicate the corresponding function will be used, only that it may be.

Please file issues any time you have to use these private knobs with a way to reproduce the issue you were seeing. Link to that issue from a comment in your code.

Added in version 3.8: _USE_POSIX_SPAWN

sched — Event scheduler

소스 코드: Lib/sched.py [https://github.com/python/cpython/tree/main/Lib/sched.py]

sched 모듈은 범용 이벤트 스케줄러를 구현하는 클래스를 정의합니다:

class sched.scheduler(timefunc=time.monotonic, delayfunc=time.sleep)

scheduler 클래스는 이벤트 스케줄링을 위한 일반적인 인터페이스를 정의합니다. “외부 세계”를 실제로 다루기 위해 두 개의 함수를 요구합니다 — timefunc는 인자 없이 호출할 수 있어야 하고, 숫자(단위가 무엇이든, “시간”)를 반환합니다. delayfunc 함수는 하나의 인자로 호출 가능해야 하며, timefunc의 출력과 호환되어야 하고, 그 시간 동안 지연시켜야 합니다. delayfunc는 다중 스레드 응용 프로그램에서 다른 스레드가 실행할 기회를 주기 위해 각 이벤트가 실행된 후 0 인자로 호출되기도 합니다.

버전 3.3에서 변경: timefunc 와 delayfunc 매개 변수는 선택적입니다.

버전 3.3에서 변경: scheduler 클래스는 다중 스레드 환경에서 안전하게 사용할 수 있습니다.

예제:

>>> import sched, time
>>> s = sched.scheduler(time.time, time.sleep)
>>> def print_time(a='default'):
...     print("From print_time", time.time(), a)
...
>>> def print_some_times():
...     print(time.time())
...     s.enter(10, 1, print_time)
...     s.enter(5, 2, print_time, argument=('positional',))
...     # despite having higher priority, 'keyword' runs after 'positional' as enter() is relative
...     s.enter(5, 1, print_time, kwargs={'a': 'keyword'})
...     s.enterabs(1_650_000_000, 10, print_time, argument=("first enterabs",))
...     s.enterabs(1_650_000_000, 5, print_time, argument=("second enterabs",))
...     s.run()
...     print(time.time())
...
>>> print_some_times()
1652342830.3640375
From print_time 1652342830.3642538 second enterabs
From print_time 1652342830.3643398 first enterabs
From print_time 1652342835.3694863 positional
From print_time 1652342835.3696074 keyword
From print_time 1652342840.369612 default
1652342840.3697174

스케줄러 객체

scheduler 인스턴스에는 다음과 같은 메서드와 어트리뷰트가 있습니다:

scheduler.enterabs(time, priority, action, argument=(), kwargs={})

새 이벤트를 예약합니다. time 인자는 생성자에 전달된 timefunc 함수의 반환 값과 호환되는 숫자 형이어야 합니다. 같은 time으로 예약된 이벤트는 priority 순으로 실행됩니다. 낮은 숫자는 높은 우선순위를 나타냅니다.

이벤트를 실행하는 것은 action(*argument, **kwargs)를 실행하는 것을 의미합니다. argument는 action에 대한 위치 인자가 들어있는 시퀀스입니다. kwargs는 action에 대한 키워드 인자가 들어있는 딕셔너리입니다.

반환 값은 나중에 이벤트를 취소하는 데 사용할 수 있는 이벤트입니다 (cancel() 참조).

버전 3.3에서 변경: argument 매개 변수는 선택적입니다.

버전 3.3에서 변경: kwargs 매개 변수가 추가되었습니다.

scheduler.enter(delay, priority, action, argument=(), kwargs={})

delay 시간 단위 후로 이벤트를 예약합니다. 상대 시간 이외의 다른 인자, 효과 및 반환 값은 enterabs()와 같습니다.

버전 3.3에서 변경: argument 매개 변수는 선택적입니다.

버전 3.3에서 변경: kwargs 매개 변수가 추가되었습니다.

scheduler.cancel(event)

큐에서 이벤트를 제거합니다. event가 현재 큐에 없으면, 이 메서드는 ValueError를 발생시킵니다.

scheduler.empty()

이벤트 큐가 비어있으면 True를 반환합니다.

scheduler.run(blocking=True)

Run all scheduled events. This method will wait (using the delayfunc function passed to the constructor) for the next event, then execute it and so on until there are no more scheduled events.

blocking이 거짓이면 시간이 도래한 (있다면) 예약된 이벤트를 모두 실행한 다음, 스케줄러에서 다음 예약된 호출까지의 (있다면) 대기시간을 반환합니다 .

action 이나 delayfunc는 예외를 발생시킬 수 있습니다. 두 경우 모두, 스케줄러는 일관된 상태를 유지하고 예외를 전파합니다. action에 의해 예외가 발생하면, 이후에 run()을 호출할 때 이벤트를 실행하려고 하지 않습니다.

일련의 이벤트가 다음 이벤트 이전에 사용 가능한 시간보다 실행하는 데 더 오래 걸리면, 스케줄러는 단순히 지연됩니다. 어떤 이벤트도 삭제되지 않습니다; 더는 적절하지 않은 이벤트를 취소할 책임은 호출 코드에 있습니다.

버전 3.3에서 변경: blocking 매개 변수가 추가되었습니다.

scheduler.queue

남은 이벤트의 리스트를 실행될 순서대로 반환하는 읽기 전용 어트리뷰트입니다. 각 이벤트는 다음과 같은 필드를 갖는 네임드 튜플로 표시됩니다: time, priority, action, argument, kwargs.

queue — A synchronized queue class

소스 코드: Lib/queue.py [https://github.com/python/cpython/tree/main/Lib/queue.py]

queue 모듈은 다중 생산자, 다중 소비자 큐를 구현합니다. 정보가 여러 스레드 간에 안전하게 교환되어야 할 때 스레드 프로그래밍에서 특히 유용합니다. 이 모듈의 Queue 클래스는 필요한 모든 로킹 개념을 구현합니다.

The module implements three types of queue, which differ only in the order in which the entries are retrieved. In a FIFO queue, the first tasks added are the first retrieved. In a LIFO queue, the most recently added entry is the first retrieved (operating like a stack). With a priority queue, the entries are kept sorted (using the heapq module) and the lowest valued entry is retrieved first.

내부적으로, 이러한 3가지 유형의 큐는 록을 사용하여 경쟁 스레드를 일시적으로 블록합니다; 그러나, 스레드 내에서의 재진입을 처리하도록 설계되지는 않았습니다.

또한, 이 모듈은 “간단한” FIFO 큐 유형인 SimpleQueue를 구현합니다. 이 특정 구현은 작은 기능을 포기하는 대신 추가 보장을 제공합니다.

queue 모듈은 다음 클래스와 예외를 정의합니다:

class queue.Queue(maxsize=0)

FIFO 큐의 생성자. maxsize는 큐에 배치할 수 있는 항목 수에 대한 상한을 설정하는 정수입니다. 일단, 이 크기에 도달하면, 큐 항목이 소비될 때까지 삽입이 블록 됩니다. maxsize가 0보다 작거나 같으면, 큐 크기는 무한합니다.

class queue.LifoQueue(maxsize=0)

LIFO 큐의 생성자. maxsize는 큐에 배치할 수 있는 항목 수에 대한 상한을 설정하는 정수입니다. 일단, 이 크기에 도달하면, 큐 항목이 소비될 때까지 삽입이 블록 됩니다. maxsize가 0보다 작거나 같으면, 큐 크기는 무한합니다.

class queue.PriorityQueue(maxsize=0)

우선순위 큐의 생성자. maxsize는 큐에 배치할 수 있는 항목 수에 대한 상한을 설정하는 정수입니다. 일단, 이 크기에 도달하면, 큐 항목이 소비될 때까지 삽입이 블록 됩니다. maxsize가 0보다 작거나 같으면, 큐 크기는 무한합니다.

The lowest valued entries are retrieved first (the lowest valued entry is the one that would be returned by min(entries)). A typical pattern for entries is a tuple in the form: (priority_number, data).

data 요소를 비교할 수 없으면, 데이터는 데이터 항목을 무시하고 우선순위 숫자만 비교하는 클래스로 감쌀 수 있습니다:

from dataclasses import dataclass, field
from typing import Any

@dataclass(order=True)
class PrioritizedItem:
    priority: int
    item: Any=field(compare=False)

class queue.SimpleQueue

상한 없는 FIFO 큐의 생성자. 단순 큐에는 작업 추적과 같은 고급 기능이 없습니다.

Added in version 3.7.

exception queue.Empty

비 블로킹 get()(또는 get_nowait())이 비어있는 Queue 객체에 호출될 때 발생하는 예외.

exception queue.Full

비 블로킹 put()(또는 put_nowait())이 가득 찬 Queue 객체에 호출될 때 발생하는 예외.

exception queue.ShutDown

Exception raised when put() or get() is called on a Queue object which has been shut down.

Added in version 3.13.

큐 객체

큐 객체(Queue, LifoQueue 또는 PriorityQueue)는 아래에 설명된 공용 메서드를 제공합니다.

Queue.qsize()

큐의 대략의 크기를 돌려줍니다. 주의하십시오, qsize() > 0 은 후속 get()이 블록 되지 않는다는 것을 보장하지 않으며, qsize() < maxsize 도 put()이 블록 되지 않는다고 보장하지 않습니다.

Queue.empty()

큐가 비어 있으면 True를, 그렇지 않으면 False를 반환합니다. empty()가 True를 반환하면, put()에 대한 후속 호출이 블록 되지 않는다고 보장하는 것은 아닙니다. 마찬가지로 empty()가 False를 반환하면, get()에 대한 후속 호출이 블록 되지 않는다고 보장하는 것은 아닙니다.

Queue.full()

큐가 가득 차면 True를, 그렇지 않으면 False를 반환합니다. full()이 True를 반환하면, get()에 대한 후속 호출이 블록 되지 않는다고 보장하는 것은 아닙니다. 마찬가지로 full()이 False를 반환하면, put()에 대한 후속 호출이 블록 되지 않는다고 보장하는 것은 아닙니다.

Queue.put(item, block=True, timeout=None)

Put item into the queue. If optional args block is true and timeout is None (the default), block if necessary until a free slot is available. If timeout is a positive number, it blocks at most timeout seconds and raises the Full exception if no free slot was available within that time. Otherwise (block is false), put an item on the queue if a free slot is immediately available, else raise the Full exception (timeout is ignored in that case).

Raises ShutDown if the queue has been shut down.

Queue.put_nowait(item)

Equivalent to put(item, block=False).

Queue.get(block=True, timeout=None)

큐에서 항목을 제거하고 반환합니다. 선택적 인자 block이 참이고 timeout이 None(기본값)이면, 항목이 사용 가능할 때까지 필요하면 블록합니다. timeout이 양수면, 최대 timeout 초 동안 블록하고 그 시간 내에 사용 가능한 항목이 없으면 Empty 예외가 발생합니다. 그렇지 않으면 (block이 거짓), 즉시 사용할 수 있는 항목이 있으면 반환하고, 그렇지 않으면 Empty 예외를 발생시킵니다 (이때 timeout은 무시됩니다).

Prior to 3.0 on POSIX systems, and for all versions on Windows, if block is true and timeout is None, this operation goes into an uninterruptible wait on an underlying lock. This means that no exceptions can occur, and in particular a SIGINT will not trigger a KeyboardInterrupt.

Raises ShutDown if the queue has been shut down and is empty, or if the queue has been shut down immediately.

Queue.get_nowait()

get(False)와 동등합니다.

큐에 넣은 작업이 데몬 소비자 스레드에 의해 완전히 처리되었는지를 추적하는 것을 지원하는 두 가지 메서드가 제공됩니다.

Queue.task_done()

앞서 큐에 넣은 작업이 완료되었음을 나타냅니다. 큐 소비자 스레드에서 사용됩니다. 작업을 꺼내는 데 사용되는 get()마다, 후속 task_done() 호출은 작업에 대한 처리가 완료되었음을 큐에 알려줍니다.

join()이 현재 블로킹 중이면, 모든 항목이 처리되면 (큐로 put() 된 모든 항목에 대해 task_done() 호출이 수신되었음을 뜻합니다) 재개됩니다.

shutdown(immediate=True) calls task_done() for each remaining item in the queue.

큐에 있는 항목보다 더 많이 호출되면 ValueError를 발생시킵니다.

Queue.join()

큐의 모든 항목을 꺼내서 처리할 때까지 블록합니다.

The count of unfinished tasks goes up whenever an item is added to the queue. The count goes down whenever a consumer thread calls task_done() to indicate that the item was retrieved and all work on it is complete. When the count of unfinished tasks drops to zero, join() unblocks.

큐에 포함된 작업이 완료될 때까지 대기하는 방법의 예:

import threading
import queue

q = queue.Queue()

def worker():
    while True:
        item = q.get()
        print(f'Working on {item}')
        print(f'Finished {item}')
        q.task_done()

# Turn-on the worker thread.
threading.Thread(target=worker, daemon=True).start()

# Send thirty task requests to the worker.
for item in range(30):
    q.put(item)

# Block until all tasks are done.
q.join()
print('All work completed')

Terminating queues

Queue objects can be made to prevent further interaction by shutting them down.

Queue.shutdown(immediate=False)

Shut down the queue, making get() and put() raise ShutDown.

By default, get() on a shut down queue will only raise once the queue is empty. Set immediate to true to make get() raise immediately instead.

All blocked callers of put() and get() will be unblocked. If immediate is true, a task will be marked as done for each remaining item in the queue, which may unblock callers of join().

Added in version 3.13.

SimpleQueue 객체

SimpleQueue 객체는 아래에서 설명하는 공용 메서드를 제공합니다.

SimpleQueue.qsize()

큐의 대략의 크기를 돌려줍니다. 주의하십시오, qsize() > 0 은 후속 get()이 블록 되지 않는다는 것을 보장하지 않습니다.

SimpleQueue.empty()

Return True if the queue is empty, False otherwise. If empty() returns False it doesn’t guarantee that a subsequent call to get() will not block.

SimpleQueue.put(item, block=True, timeout=None)

item을 큐에 넣습니다. 이 메서드는 결코 블록하지 않고 항상 성공합니다 (메모리 할당 실패와 같은 잠재적 저수준 에러 제외). 선택적 인자 block과 timeout은 무시되고 Queue.put()과의 호환성을 위해서만 제공됩니다.

CPython 구현 상세: This method has a C implementation which is reentrant. That is, a put() or get() call can be interrupted by another put() call in the same thread without deadlocking or corrupting internal state inside the queue. This makes it appropriate for use in destructors such as __del__ methods or weakref callbacks.

SimpleQueue.put_nowait(item)

Equivalent to put(item, block=False), provided for compatibility with Queue.put_nowait().

SimpleQueue.get(block=True, timeout=None)

큐에서 항목을 제거하고 반환합니다. 선택적 인자 block이 참이고 timeout이 None(기본값)이면, 항목이 사용 가능할 때까지 필요하면 블록합니다. timeout이 양수면, 최대 timeout 초 동안 블록하고 그 시간 내에 사용 가능한 항목이 없으면 Empty 예외가 발생합니다. 그렇지 않으면 (block이 거짓), 즉시 사용할 수 있는 항목이 있으면 반환하고, 그렇지 않으면 Empty 예외를 발생시킵니다 (이때 timeout은 무시됩니다).

SimpleQueue.get_nowait()

get(False)와 동등합니다.

더 보기

multiprocessing.Queue 클래스

(다중 스레드 대신) 다중 프로세스 문맥에서 사용하기 위한 큐 클래스.

collections.deque는 록을 필요로하지 않고 인덱싱을 지원하는 빠른 원자적 append()와 popleft() 연산을 제공하는 크기 제한 없는 큐의 대체 구현입니다.

contextvars — Context Variables

이 모듈은 컨텍스트-로컬 상태를 관리, 저장, 액세스하기 위한 API를 제공합니다. ContextVar 클래스는 컨텍스트 변수 를 선언하고 사용하는 데 쓰입니다. copy_context() 함수와 Context 클래스는 비동기 프레임워크에서 현재 컨텍스트를 관리하는 데 사용해야 합니다.

Context managers that have state should use Context Variables instead of threading.local() to prevent their state from bleeding to other code unexpectedly, when used in concurrent code.

자세한 내용은 PEP 567 [https://peps.python.org/pep-0567/]을 참조하십시오.

Added in version 3.7.

컨텍스트 변수

class contextvars.ContextVar(name[, *, default])

이 클래스는 새로운 컨텍스트 변수를 선언하는 데 사용됩니다. 예:

var: ContextVar[int] = ContextVar('var', default=42)

필수 name 매개 변수는 인트로스팩션 및 디버그 목적으로 사용됩니다.

선택적 키워드 전용 default 매개 변수는 변수에 대한 값이 현재 컨텍스트에서 발견되지 않으면 ContextVar.get() 에 의해 반환됩니다.

중요: 컨텍스트 변수는 최상위 모듈 수준에서 만들어져야 하고 클로저에서 만들어져서는 안 됩니다. Context 객체는 컨텍스트 변수에 대해 강한 참조를 유지해서 컨텍스트 변수가 제대로 가비지 수집되지 못하게 합니다.

name

변수의 이름. 읽기 전용 프로퍼티입니다.

Added in version 3.7.1.

get([default])

현재 컨텍스트의 컨텍스트 변수에 대한 값을 반환합니다.

현재 컨텍스트에서 변수에 대한 값이 없는 경우 메서드는:

제공된 경우 메서드의 default 인자 값을 반환합니다; 또는

생성 시에 제공된 경우, 컨텍스트 변수의 기본값을 반환합니다; 또는

LookupError 를 발생시킵니다.

set(value)

현재 컨텍스트에서 컨텍스트 변수의 새 값을 설정하려면 호출합니다.

필수 value 인자는 컨텍스트 변수의 새 값입니다.

ContextVar.reset() 메서드를 통해 변수를 이전 값으로 복원하는 데 사용할 수 있는 Token 객체를 반환합니다.

reset(token)

token 을 생성 한 ContextVar.set() 이 사용되기 전의 값으로 컨텍스트 변수를 재설정합니다.

예를 들면:

var = ContextVar('var')

token = var.set('new value')
# code that uses 'var'; var.get() returns 'new value'.
var.reset(token)

# After the reset call the var has no value again, so
# var.get() would raise a LookupError.

class contextvars.Token

Token 객체는 ContextVar.set() 메서드에 의해 반환됩니다. ContextVar.reset() 메서드에 전달해서 변수의 값을 해당 set 이전의 값으로 되돌릴 수 있습니다.

var

읽기 전용 프로퍼티. 토큰을 생성 한 ContextVar 객체를 가리 킵니다.

old_value

A read-only property. Set to the value the variable had before the ContextVar.set() method call that created the token. It points to Token.MISSING if the variable was not set before the call.

MISSING

Token.old_value 에 의해 사용되는 표지 객체.

수동 컨텍스트 관리

contextvars.copy_context()

현재 Context 객체의 복사본을 반환합니다.

다음 코드 조각은 현재 컨텍스트의 복사본을 가져와서 모든 변수와 그 변수에 설정된 값을 출력합니다:

ctx: Context = copy_context()
print(list(ctx.items()))

The function has an O(1) complexity, i.e. works equally fast for contexts with a few context variables and for contexts that have a lot of them.

class contextvars.Context

ContextVars 에서 그 값으로의 매핑.

Context() 는 값이 없는 빈 컨텍스트를 만듭니다. 현재 컨텍스트의 복사본을 얻으려면 copy_context() 함수를 사용하십시오.

Each thread has its own effective stack of Context objects. The current context is the Context object at the top of the current thread’s stack. All Context objects in the stacks are considered to be entered.

Entering a context, which can be done by calling its run() method, makes the context the current context by pushing it onto the top of the current thread’s context stack.

Exiting from the current context, which can be done by returning from the callback passed to the run() method, restores the current context to what it was before the context was entered by popping the context off the top of the context stack.

Since each thread has its own context stack, ContextVar objects behave in a similar fashion to threading.local() when values are assigned in different threads.

Attempting to enter an already entered context, including contexts entered in other threads, raises a RuntimeError.

After exiting a context, it can later be re-entered (from any thread).

Any changes to ContextVar values via the ContextVar.set() method are recorded in the current context. The ContextVar.get() method returns the value associated with the current context. Exiting a context effectively reverts any changes made to context variables while the context was entered (if needed, the values can be restored by re-entering the context).

Context는 collections.abc.Mapping 인터페이스를 구현합니다.

run(callable, *args, **kwargs)

Enters the Context, executes callable(*args, **kwargs), then exits the Context. Returns callable’s return value, or propagates an exception if one occurred.

Example:

import contextvars

var = contextvars.ContextVar('var')
var.set('spam')
print(var.get())  # 'spam'

ctx = contextvars.copy_context()

def main():
    # 'var' was set to 'spam' before
    # calling 'copy_context()' and 'ctx.run(main)', so:
    print(var.get())  # 'spam'
    print(ctx[var])  # 'spam'

    var.set('ham')

    # Now, after setting 'var' to 'ham':
    print(var.get())  # 'ham'
    print(ctx[var])  # 'ham'

# Any changes that the 'main' function makes to 'var'
# will be contained in 'ctx'.
ctx.run(main)

# The 'main()' function was run in the 'ctx' context,
# so changes to 'var' are contained in it:
print(ctx[var])  # 'ham'

# However, outside of 'ctx', 'var' is still set to 'spam':
print(var.get())  # 'spam'

copy()

컨텍스트 객체의 얕은 복사본을 반환합니다.

var in context

context 에 var 의 값이 설정되었으면 True 를, 그렇지 않으면 False를 반환합니다.

context[var]

var ContextVar 변수의 값을 돌려줍니다. 컨텍스트 객체에 변수가 설정되어 있지 않으면 KeyError 가 발생합니다.

get(var[, default])

컨텍스트 객체에 var 의 값이 있으면, var 의 값을 돌려줍니다. 그렇지 않으면 default 를 반환합니다. default 가 주어지지 않으면 None 을 반환합니다.

iter(context)

컨텍스트 객체에 저장된 변수에 대한 이터레이터를 반환합니다.

len(proxy)

컨텍스트 객체에 설정된 변수의 개수를 반환합니다.

keys()

컨텍스트 객체의 모든 변수 목록을 반환합니다.

values()

컨텍스트 객체의 모든 변수의 값 목록을 반환합니다.

items()

컨텍스트 객체에서 모든 변수와 해당 값을 포함하는 2-튜플의 목록을 반환합니다.

asyncio 지원

컨텍스트 변수는 asyncio 에서 기본적으로 지원되며 추가 구성없이 사용할 수 있습니다. 예를 들어, 이것은 컨텍스트 변수를 사용하여, 원격 클라이언트의 주소를 해당 클라이언트를 처리하는 Task에서 사용할 수 있도록 하는 간단한 메아리 서버입니다:

import asyncio
import contextvars

client_addr_var = contextvars.ContextVar('client_addr')

def render_goodbye():
    # The address of the currently handled client can be accessed
    # without passing it explicitly to this function.

    client_addr = client_addr_var.get()
    return f'Good bye, client @ {client_addr}\r\n'.encode()

async def handle_request(reader, writer):
    addr = writer.transport.get_extra_info('socket').getpeername()
    client_addr_var.set(addr)

    # In any code that we call is now possible to get
    # client's address by calling 'client_addr_var.get()'.

    while True:
        line = await reader.readline()
        print(line)
        if not line.strip():
            break

    writer.write(b'HTTP/1.1 200 OK\r\n')  # status line
    writer.write(b'\r\n')  # headers
    writer.write(render_goodbye())  # body
    writer.close()

async def main():
    srv = await asyncio.start_server(
        handle_request, '127.0.0.1', 8081)

    async with srv:
        await srv.serve_forever()

asyncio.run(main())

# To test it you can use telnet or curl:
#     telnet 127.0.0.1 8081
#     curl 127.0.0.1:8081

_thread — Low-level threading API

이 모듈은 다중 스레드(경량 프로세스 (light-weight processes) 나 태스크 (tasks)라고도 합니다)로 작업하는데 필요한 저수준 기본 요소를 제공합니다 — 전역 데이터 공간을 공유하는 여러 개의 제어 스레드를 뜻합니다. 동기화를 위해서, 간단한 록(뮤텍스 (mutexes)나 이진 세마포어 (binary semaphores)라고도 합니다)이 제공됩니다. threading 모듈은 이 모듈 위에 구축되어 사용하기 쉬운 고수준의 스레딩 API를 제공합니다.

버전 3.7에서 변경: 이 모듈은 선택 사항이었지만, 이제는 항상 사용할 수 있습니다.

이 모듈은 다음 상수와 함수를 정의합니다:

exception _thread.error

스레드 특정 에러에서 발생합니다.

버전 3.3에서 변경: 이것은 이제 내장 RuntimeError의 동의어입니다.

_thread.LockType

이것은 록 객체의 형입니다.

_thread.start_new_thread(function, args[, kwargs])

새 스레드를 시작하고 식별자를 반환합니다. 스레드는 인자 목록 args(튜플이어야 합니다)로 함수 function을 실행합니다. 선택적 kwargs 인자는 키워드 인자 딕셔너리를 지정합니다.

함수가 반환되면, 스레드는 조용히 종료합니다.

함수가 처리되지 않은 예외로 종료되면, 예외를 처리하기 위해 sys.unraisablehook()이 호출됩니다. 훅 인자의 object 어트리뷰트는 function입니다. 기본적으로, 스택 트레이스가 인쇄된 다음 스레드가 종료합니다 (하지만 다른 스레드는 계속 실행됩니다).

함수가 SystemExit 예외를 발생시키면, 조용히 무시됩니다.

Raises an auditing event _thread.start_new_thread with arguments function, args, kwargs.

버전 3.8에서 변경: sys.unraisablehook()은 이제 처리되지 않은 예외를 처리하는 데 사용됩니다.

_thread.interrupt_main(signum=signal.SIGINT, /)

Simulate the effect of a signal arriving in the main thread. A thread can use this function to interrupt the main thread, though there is no guarantee that the interruption will happen immediately.

If given, signum is the number of the signal to simulate. If signum is not given, signal.SIGINT is simulated.

If the given signal isn’t handled by Python (it was set to signal.SIG_DFL or signal.SIG_IGN), this function does nothing.

버전 3.10에서 변경: The signum argument is added to customize the signal number.

참고

This does not emit the corresponding signal but schedules a call to the associated handler (if it exists). If you want to truly emit the signal, use signal.raise_signal().

_thread.exit()

SystemExit 예외를 발생시킵니다. 잡히지 않으면, 스레드가 조용히 종료되도록 합니다.

_thread.allocate_lock()

새로운 록 객체를 반환합니다. 록의 메서드는 아래에 설명되어 있습니다. 록은 초기에 잠금 해제되어 있습니다.

_thread.get_ident()

현재 스레드의 ‘스레드 식별자(thread identifier)’를 반환합니다. 이것은 0이 아닌 정수입니다. 그 값은 직접적인 의미가 없습니다; 이것은 예를 들어 스레드 특정 데이터의 딕셔너리를 인덱싱하는 데 사용되는 매직 쿠키로 사용하려는 의도입니다. 스레드 식별자는 스레드가 종료되고 다른 스레드가 만들어질 때 재활용될 수 있습니다.

_thread.get_native_id()

커널에 의해 할당된 현재 스레드의 네이티브 정수 스레드 ID를 반환합니다. 이것은 음수가 아닌 정수입니다. 이 값은 시스템 전반에 걸쳐 이 특정 스레드를 고유하게 식별하는 데 사용될 수 있습니다 (스레드가 종료될 때까지, 그 후에는 값이 OS에 의해 재활용될 수 있습니다).

Availability: Windows, FreeBSD, Linux, macOS, OpenBSD, NetBSD, AIX, DragonFlyBSD, GNU/kFreeBSD.

Added in version 3.8.

버전 3.13에서 변경: Added support for GNU/kFreeBSD.

_thread.stack_size([size])

새로운 스레드를 만들 때 사용된 스레드의 스택 크기를 반환합니다. 선택적 size 인자는 이후에 만들어지는 스레드에 사용할 스택 크기를 지정하며, 0(플랫폼 또는 구성된 기본값을 사용합니다)이나 최소 32,768(32 KiB)의 양의 정숫값이어야 합니다. size를 지정하지 않으면 0이 사용됩니다. 스레드 스택 크기 변경이 지원되지 않으면, RuntimeError가 발생합니다. 지정된 스택 크기가 유효하지 않으면, ValueError가 발생하고, 스택 크기는 변경되지 않습니다. 32 KiB는 현재 인터프리터 자체에 충분한 스택 공간을 보장하기 위해 지원되는 최소 스택 크기 값입니다. 일부 플랫폼에서는 스택 크기 값에 특별한 제한이 있을 수 있습니다, 가령 최소 스택 크기 > 32KB를 요구하거나 시스템 메모리 페이지 크기의 배수로 할당하는 것을 요구할 수 있습니다 - 자세한 내용은 플랫폼 설명서를 참조하십시오 (4 KiB 페이지가 일반적입니다; 더 구체적인 정보가 없으면 스택 크기로 4096의 배수를 사용하는 것이 제안된 방법입니다).

Availability: Windows, pthreads.

Unix platforms with POSIX threads support.

_thread.TIMEOUT_MAX

The maximum value allowed for the timeout parameter of Lock.acquire. Specifying a timeout greater than this value will raise an OverflowError.

Added in version 3.2.

록 객체에는 다음과 같은 메서드가 있습니다:

lock.acquire(blocking=True, timeout=-1)

선택적 인자가 아무것도 없으면, 이 메서드는 조건 없이 록을 획득합니다, 필요하면 다른 스레드가 록을 해제할 때까지 대기합니다 (한 번에 하나의 스레드만 록을 획득할 수 있습니다 — 이것이 록의 존재 이유입니다).

If the blocking argument is present, the action depends on its value: if it is false, the lock is only acquired if it can be acquired immediately without waiting, while if it is true, the lock is acquired unconditionally as above.

If the floating-point timeout argument is present and positive, it specifies the maximum wait time in seconds before returning. A negative timeout argument specifies an unbounded wait. You cannot specify a timeout if blocking is false.

록이 성공적으로 획득되면 반환 값은 True이고, 그렇지 않으면 False입니다.

버전 3.2에서 변경: timeout 매개 변수가 추가되었습니다.

버전 3.2에서 변경: 록 획득은 이제 POSIX의 시그널에 의해 중단될 수 있습니다.

버전 3.14에서 변경: Lock acquires can now be interrupted by signals on Windows.

lock.release()

록을 해제합니다. 록은 반드시 이전에 획득된 것이어야 하지만, 반드시 같은 스레드에 의해 획득된 것일 필요는 없습니다.

lock.locked()

록의 상태를 반환합니다: 어떤 스레드에 의해 획득되었으면 True, 그렇지 않으면 False를 반환합니다.

이러한 메서드 외에도, with 문을 통해 록 객체를 사용할 수도 있습니다, 예를 들어:

import _thread

a_lock = _thread.allocate_lock()

with a_lock:
    print("a_lock is locked while this executes")

주의 사항:

Interrupts always go to the main thread (the KeyboardInterrupt exception will be received by that thread.)

sys.exit()를 호출하거나 SystemExit 예외를 발생시키는 것은 _thread.exit()를 호출하는 것과 동등합니다.

메인 스레드가 종료할 때, 다른 스레드가 살아남는지는 시스템이 정의합니다. 대부분 시스템에서, try … finally 절을 실행하거나 객체 파괴자(destructor)를 실행하지 않고 강제 종료됩니다.

네트워킹과 프로세스 간 통신

이 장에서 설명하는 모듈은 네트워킹과 프로세스 간 통신을 위한 메커니즘을 제공합니다.

어떤 모듈은 같은 기계에 있는 두 개의 프로세스에서만 작동합니다 (예를 들어, signal과 mmap). 다른 모듈은 두 개 이상의 프로세스가 여러 기계에서 통신하는 데 사용할 수 있는 네트워킹 프로토콜을 지원합니다.

이 장에서 설명하는 모듈 목록은 다음과 같습니다:

asyncio — Asynchronous I/O

socket — Low-level networking interface

ssl — TLS/SSL wrapper for socket objects

select — Waiting for I/O completion

selectors — High-level I/O multiplexing

signal — Set handlers for asynchronous events

mmap — Memory-mapped file support

asyncio — Asynchronous I/O

Hello World!

import asyncio

async def main():
    print('Hello ...')
    await asyncio.sleep(1)
    print('... World!')

asyncio.run(main())

asyncio는 async/await 구문을 사용하여 동시성 코드를 작성하는 라이브러리입니다.

asyncio는 고성능 네트워크 및 웹 서버, 데이터베이스 연결 라이브러리, 분산 작업 큐 등을 제공하는 여러 파이썬 비동기 프레임워크의 기반으로 사용됩니다.

asyncio는 종종 IO 병목이면서 고수준의 구조화된 네트워크 코드에 가장 적합합니다.

asyncio는 다음과 같은 작업을 위한 고수준 API 집합을 제공합니다:

파이썬 코루틴들을 동시에 실행하고 실행을 완전히 제어할 수 있습니다.

네트워크 IO와 IPC를 수행합니다;

자식 프로세스를 제어합니다;

큐를 통해 작업을 분산합니다;

동시성 코드를 동기화합니다;

또한, 라이브러리와 프레임워크 개발자가 다음과 같은 작업을 할 수 있도록 하는 저수준 API가 있습니다:

create and manage event loops, which provide asynchronous APIs for networking, running subprocesses, handling OS signals, etc;

트랜스포트를 사용하여 효율적인 프로토콜을 구현합니다.

콜백 기반 라이브러리와 async/await 구문을 사용한 코드 간에 다리를 놓습니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

asyncio REPL

You can experiment with an asyncio concurrent context in the REPL:

$ python -m asyncio
asyncio REPL ...
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
>>> import asyncio
>>> await asyncio.sleep(10, result='hello')
'hello'

Raises an auditing event cpython.run_stdin with no arguments.

버전 3.12.5에서 변경: (also 3.11.10, 3.10.15, 3.9.20, and 3.8.20) Emits audit events.

버전 3.13에서 변경: Uses PyREPL if possible, in which case PYTHONSTARTUP is also executed. Emits audit events.

레퍼런스

고수준 API

Runners

코루틴과 태스크

스트림

동기화 프리미티브

서브 프로세스

큐

예외

저수준 API

이벤트 루프

퓨처

트랜스포트와 프로토콜

정책

플랫폼 지원

Extending

가이드 및 자습서

고수준 API 색인

저수준 API 색인

asyncio로 개발하기

참고

asyncio의 소스 코드는 Lib/asyncio/ [https://github.com/python/cpython/tree/main/Lib/asyncio/]에서 찾을 수 있습니다.

Runners

Source code: Lib/asyncio/runners.py [https://github.com/python/cpython/tree/main/Lib/asyncio/runners.py]

This section outlines high-level asyncio primitives to run asyncio code.

They are built on top of an event loop with the aim to simplify async code usage for common wide-spread scenarios.

Running an asyncio Program

Runner context manager

Handling Keyboard Interruption

Running an asyncio Program

asyncio.run(coro, *, debug=None, loop_factory=None)

Execute coro in an asyncio event loop and return the result.

The argument can be any awaitable object.

This function runs the awaitable, taking care of managing the asyncio event loop, finalizing asynchronous generators, and closing the executor.

This function cannot be called when another asyncio event loop is running in the same thread.

If debug is True, the event loop will be run in debug mode. False disables debug mode explicitly. None is used to respect the global 디버그 모드 settings.

If loop_factory is not None, it is used to create a new event loop; otherwise asyncio.new_event_loop() is used. The loop is closed at the end. This function should be used as a main entry point for asyncio programs, and should ideally only be called once. It is recommended to use loop_factory to configure the event loop instead of policies. Passing asyncio.EventLoop allows running asyncio without the policy system.

The executor is given a timeout duration of 5 minutes to shutdown. If the executor hasn’t finished within that duration, a warning is emitted and the executor is closed.

Example:

async def main():
    await asyncio.sleep(1)
    print('hello')

asyncio.run(main())

Added in version 3.7.

버전 3.9에서 변경: Updated to use loop.shutdown_default_executor().

버전 3.10에서 변경: debug is None by default to respect the global debug mode settings.

버전 3.12에서 변경: Added loop_factory parameter.

버전 3.14에서 변경: coro can be any awaitable object.

Runner context manager

class asyncio.Runner(*, debug=None, loop_factory=None)

A context manager that simplifies multiple async function calls in the same context.

Sometimes several top-level async functions should be called in the same event loop and contextvars.Context.

If debug is True, the event loop will be run in debug mode. False disables debug mode explicitly. None is used to respect the global 디버그 모드 settings.

loop_factory could be used for overriding the loop creation. It is the responsibility of the loop_factory to set the created loop as the current one. By default asyncio.new_event_loop() is used and set as current event loop with asyncio.set_event_loop() if loop_factory is None.

Basically, asyncio.run() example can be rewritten with the runner usage:

async def main():
    await asyncio.sleep(1)
    print('hello')

with asyncio.Runner() as runner:
    runner.run(main())

Added in version 3.11.

run(coro, *, context=None)

Execute coro in the embedded event loop.

The argument can be any awaitable object.

If the argument is a coroutine, it is wrapped in a Task.

An optional keyword-only context argument allows specifying a custom contextvars.Context for the code to run in. The runner’s default context is used if context is None.

Returns the awaitable’s result or raises an exception.

This function cannot be called when another asyncio event loop is running in the same thread.

버전 3.14에서 변경: coro can be any awaitable object.

close()

Close the runner.

Finalize asynchronous generators, shutdown default executor, close the event loop and release embedded contextvars.Context.

get_loop()

Return the event loop associated with the runner instance.

참고

Runner uses the lazy initialization strategy, its constructor doesn’t initialize underlying low-level structures.

Embedded loop and context are created at the with body entering or the first call of run() or get_loop().

Handling Keyboard Interruption

Added in version 3.11.

When signal.SIGINT is raised by Ctrl-C, KeyboardInterrupt exception is raised in the main thread by default. However this doesn’t work with asyncio because it can interrupt asyncio internals and can hang the program from exiting.

To mitigate this issue, asyncio handles signal.SIGINT as follows:

asyncio.Runner.run() installs a custom signal.SIGINT handler before any user code is executed and removes it when exiting from the function.

The Runner creates the main task for the passed coroutine for its execution.

When signal.SIGINT is raised by Ctrl-C, the custom signal handler cancels the main task by calling asyncio.Task.cancel() which raises asyncio.CancelledError inside the main task. This causes the Python stack to unwind, try/except and try/finally blocks can be used for resource cleanup. After the main task is cancelled, asyncio.Runner.run() raises KeyboardInterrupt.

A user could write a tight loop which cannot be interrupted by asyncio.Task.cancel(), in which case the second following Ctrl-C immediately raises the KeyboardInterrupt without cancelling the main task.

코루틴과 태스크

이 절에서는 코루틴과 태스크로 작업하기 위한 고급 asyncio API에 관해 설명합니다.

코루틴

어웨이터블

태스크 만들기

Task Cancellation

Task Groups

잠자기

동시에 태스크 실행하기

Eager Task Factory

취소로부터 보호하기

시간제한

대기 프리미티브

스레드에서 실행하기

다른 스레드에서 예약하기

인트로스펙션

Task 객체

코루틴

Source code: Lib/asyncio/coroutines.py [https://github.com/python/cpython/tree/main/Lib/asyncio/coroutines.py]

Coroutines declared with the async/await syntax is the preferred way of writing asyncio applications. For example, the following snippet of code prints “hello”, waits 1 second, and then prints “world”:

>>> import asyncio

>>> async def main():
...     print('hello')
...     await asyncio.sleep(1)
...     print('world')

>>> asyncio.run(main())
hello
world

단지 코루틴을 호출하는 것으로 실행되도록 예약하는 것은 아닙니다:

>>> main()
<coroutine object main at 0x1053bb7c8>

To actually run a coroutine, asyncio provides the following mechanisms:

최상위 진입점 “main()” 함수를 실행하는 asyncio.run() 함수 (위의 예를 보세요.)

코루틴을 기다리기. 다음 코드 조각은 1초를 기다린 후 “hello”를 인쇄한 다음 또 2초를 기다린 후 “world”를 인쇄합니다:

import asyncio
import time

async def say_after(delay, what):
    await asyncio.sleep(delay)
    print(what)

async def main():
    print(f"started at {time.strftime('%X')}")

    await say_after(1, 'hello')
    await say_after(2, 'world')

    print(f"finished at {time.strftime('%X')}")

asyncio.run(main())

예상 출력:

started at 17:13:52
hello
world
finished at 17:13:55

코루틴을 asyncio 태스크로 동시에 실행하는 asyncio.create_task() 함수.

위의 예를 수정해서 두 개의 say_after 코루틴을 동시에 실행해 봅시다:

async def main():
    task1 = asyncio.create_task(
        say_after(1, 'hello'))

    task2 = asyncio.create_task(
        say_after(2, 'world'))

    print(f"started at {time.strftime('%X')}")

    # Wait until both tasks are completed (should take
    # around 2 seconds.)
    await task1
    await task2

    print(f"finished at {time.strftime('%X')}")

예상 출력은 이제 코드 조각이 이전보다 1초 빠르게 실행되었음을 보여줍니다:

started at 17:14:32
hello
world
finished at 17:14:34

The asyncio.TaskGroup class provides a more modern alternative to create_task(). Using this API, the last example becomes:

async def main():
    async with asyncio.TaskGroup() as tg:
        task1 = tg.create_task(
            say_after(1, 'hello'))

        task2 = tg.create_task(
            say_after(2, 'world'))

        print(f"started at {time.strftime('%X')}")

    # The await is implicit when the context manager exits.

    print(f"finished at {time.strftime('%X')}")

The timing and output should be the same as for the previous version.

Added in version 3.11: asyncio.TaskGroup.

어웨이터블

우리는 객체가 await 표현식에서 사용될 수 있을 때 어웨이터블 객체라고 말합니다. 많은 asyncio API는 어웨이터블을 받아들이도록 설계되었습니다.

어웨이터블 객체에는 세 가지 주요 유형이 있습니다: 코루틴, 태스크 및 퓨처.

코루틴

파이썬 코루틴은 어웨이터블이므로 다른 코루틴에서 기다릴 수 있습니다:

import asyncio

async def nested():
    return 42

async def main():
    # Nothing happens if we just call "nested()".
    # A coroutine object is created but not awaited,
    # so it *won't run at all*.
    nested()  # will raise a "RuntimeWarning".

    # Let's do it differently now and await it:
    print(await nested())  # will print "42".

asyncio.run(main())

중요

이 설명서에서 “코루틴” 이라는 용어는 두 가지 밀접한 관련 개념에 사용될 수 있습니다:

코루틴 함수: async def 함수;

코루틴 객체: 코루틴 함수를 호출하여 반환된 객체.

태스크

태스크는 코루틴을 동시에 예약하는 데 사용됩니다.

코루틴이 asyncio.create_task()와 같은 함수를 사용하여 태스크로 싸일 때 코루틴은 곧 실행되도록 자동으로 예약됩니다:

import asyncio

async def nested():
    return 42

async def main():
    # Schedule nested() to run soon concurrently
    # with "main()".
    task = asyncio.create_task(nested())

    # "task" can now be used to cancel "nested()", or
    # can simply be awaited to wait until it is complete:
    await task

asyncio.run(main())

퓨처

Future는 비동기 연산의 최종 결과를 나타내는 특별한 저수준 어웨이터블 객체입니다.

Future 객체를 기다릴 때, 그것은 코루틴이 Future가 다른 곳에서 해결될 때까지 기다릴 것을 뜻합니다.

콜백 기반 코드를 async/await와 함께 사용하려면 asyncio의 Future 객체가 필요합니다.

일반적으로 응용 프로그램 수준 코드에서 Future 객체를 만들 필요는 없습니다.

때때로 라이브러리와 일부 asyncio API에 의해 노출되는 Future 객체를 기다릴 수 있습니다:

async def main():
    await function_that_returns_a_future_object()

    # this is also valid:
    await asyncio.gather(
        function_that_returns_a_future_object(),
        some_python_coroutine()
    )

Future 객체를 반환하는 저수준 함수의 좋은 예는 loop.run_in_executor()입니다.

태스크 만들기

Source code: Lib/asyncio/tasks.py [https://github.com/python/cpython/tree/main/Lib/asyncio/tasks.py]

asyncio.create_task(coro, *, name=None, context=None)

coro 코루틴을 Task로 감싸고 실행을 예약합니다. Task 객체를 반환합니다.

name이 None이 아니면, Task.set_name()을 사용하여 태스크의 이름으로 설정됩니다.

An optional keyword-only context argument allows specifying a custom contextvars.Context for the coro to run in. The current context copy is created when no context is provided.

get_running_loop()에 의해 반환된 루프에서 태스크가 실행되고, 현재 스레드에 실행 중인 루프가 없으면 RuntimeError가 발생합니다.

참고

asyncio.TaskGroup.create_task() is a new alternative leveraging structural concurrency; it allows for waiting for a group of related tasks with strong safety guarantees.

중요

Save a reference to the result of this function, to avoid a task disappearing mid-execution. The event loop only keeps weak references to tasks. A task that isn’t referenced elsewhere may get garbage collected at any time, even before it’s done. For reliable “fire-and-forget” background tasks, gather them in a collection:

background_tasks = set()

for i in range(10):
    task = asyncio.create_task(some_coro(param=i))

    # Add task to the set. This creates a strong reference.
    background_tasks.add(task)

    # To prevent keeping references to finished tasks forever,
    # make each task remove its own reference from the set after
    # completion:
    task.add_done_callback(background_tasks.discard)

Added in version 3.7.

버전 3.8에서 변경: Added the name parameter.

버전 3.11에서 변경: Added the context parameter.

Task Cancellation

Tasks can easily and safely be cancelled. When a task is cancelled, asyncio.CancelledError will be raised in the task at the next opportunity.

It is recommended that coroutines use try/finally blocks to robustly perform clean-up logic. In case asyncio.CancelledError is explicitly caught, it should generally be propagated when clean-up is complete. asyncio.CancelledError directly subclasses BaseException so most code will not need to be aware of it.

The asyncio components that enable structured concurrency, like asyncio.TaskGroup and asyncio.timeout(), are implemented using cancellation internally and might misbehave if a coroutine swallows asyncio.CancelledError. Similarly, user code should not generally call uncancel. However, in cases when suppressing asyncio.CancelledError is truly desired, it is necessary to also call uncancel() to completely remove the cancellation state.

Task Groups

Task groups combine a task creation API with a convenient and reliable way to wait for all tasks in the group to finish.

class asyncio.TaskGroup

An asynchronous context manager holding a group of tasks. Tasks can be added to the group using create_task(). All tasks are awaited when the context manager exits.

Added in version 3.11.

create_task(coro, *, name=None, context=None)

Create a task in this task group. The signature matches that of asyncio.create_task(). If the task group is inactive (e.g. not yet entered, already finished, or in the process of shutting down), we will close the given coro.

버전 3.13에서 변경: Close the given coroutine if the task group is not active.

예:

async def main():
    async with asyncio.TaskGroup() as tg:
        task1 = tg.create_task(some_coro(...))
        task2 = tg.create_task(another_coro(...))
    print(f"Both tasks have completed now: {task1.result()}, {task2.result()}")

The async with statement will wait for all tasks in the group to finish. While waiting, new tasks may still be added to the group (for example, by passing tg into one of the coroutines and calling tg.create_task() in that coroutine). Once the last task has finished and the async with block is exited, no new tasks may be added to the group.

The first time any of the tasks belonging to the group fails with an exception other than asyncio.CancelledError, the remaining tasks in the group are cancelled. No further tasks can then be added to the group. At this point, if the body of the async with statement is still active (i.e., __aexit__() hasn’t been called yet), the task directly containing the async with statement is also cancelled. The resulting asyncio.CancelledError will interrupt an await, but it will not bubble out of the containing async with statement.

Once all tasks have finished, if any tasks have failed with an exception other than asyncio.CancelledError, those exceptions are combined in an ExceptionGroup or BaseExceptionGroup (as appropriate; see their documentation) which is then raised.

Two base exceptions are treated specially: If any task fails with KeyboardInterrupt or SystemExit, the task group still cancels the remaining tasks and waits for them, but then the initial KeyboardInterrupt or SystemExit is re-raised instead of ExceptionGroup or BaseExceptionGroup.

If the body of the async with statement exits with an exception (so __aexit__() is called with an exception set), this is treated the same as if one of the tasks failed: the remaining tasks are cancelled and then waited for, and non-cancellation exceptions are grouped into an exception group and raised. The exception passed into __aexit__(), unless it is asyncio.CancelledError, is also included in the exception group. The same special case is made for KeyboardInterrupt and SystemExit as in the previous paragraph.

Task groups are careful not to mix up the internal cancellation used to “wake up” their __aexit__() with cancellation requests for the task in which they are running made by other parties. In particular, when one task group is syntactically nested in another, and both experience an exception in one of their child tasks simultaneously, the inner task group will process its exceptions, and then the outer task group will receive another cancellation and process its own exceptions.

In the case where a task group is cancelled externally and also must raise an ExceptionGroup, it will call the parent task’s cancel() method. This ensures that a asyncio.CancelledError will be raised at the next await, so the cancellation is not lost.

Task groups preserve the cancellation count reported by asyncio.Task.cancelling().

버전 3.13에서 변경: Improved handling of simultaneous internal and external cancellations and correct preservation of cancellation counts.

Terminating a Task Group

While terminating a task group is not natively supported by the standard library, termination can be achieved by adding an exception-raising task to the task group and ignoring the raised exception:

import asyncio
from asyncio import TaskGroup

class TerminateTaskGroup(Exception):
    """Exception raised to terminate a task group."""

async def force_terminate_task_group():
    """Used to force termination of a task group."""
    raise TerminateTaskGroup()

async def job(task_id, sleep_time):
    print(f'Task {task_id}: start')
    await asyncio.sleep(sleep_time)
    print(f'Task {task_id}: done')

async def main():
    try:
        async with TaskGroup() as group:
            # spawn some tasks
            group.create_task(job(1, 0.5))
            group.create_task(job(2, 1.5))
            # sleep for 1 second
            await asyncio.sleep(1)
            # add an exception-raising task to force the group to terminate
            group.create_task(force_terminate_task_group())
    except* TerminateTaskGroup:
        pass

asyncio.run(main())

Expected output:

Task 1: start
Task 2: start
Task 1: done

잠자기

coroutine asyncio.sleep(delay, result=None)

delay 초 동안 블록합니다.

result가 제공되면, 코루틴이 완료될 때 호출자에게 반환됩니다.

sleep()은 항상 현재 태스크를 일시 중단해서 다른 태스크를 실행할 수 있도록 합니다.

Setting the delay to 0 provides an optimized path to allow other tasks to run. This can be used by long-running functions to avoid blocking the event loop for the full duration of the function call.

5초 동안 현재 날짜를 매초 표시하는 코루틴의 예:

import asyncio
import datetime

async def display_date():
    loop = asyncio.get_running_loop()
    end_time = loop.time() + 5.0
    while True:
        print(datetime.datetime.now())
        if (loop.time() + 1.0) >= end_time:
            break
        await asyncio.sleep(1)

asyncio.run(display_date())

버전 3.10에서 변경: Removed the loop parameter.

버전 3.13에서 변경: Raises ValueError if delay is nan.

동시에 태스크 실행하기

awaitable asyncio.gather(*aws, return_exceptions=False)

aws 시퀀스에 있는 어웨이터블 객체를 동시에 실행합니다.

aws에 있는 어웨이터블이 코루틴이면 자동으로 태스크로 예약됩니다.

모든 어웨이터블이 성공적으로 완료되면, 결과는 반환된 값들이 합쳐진 리스트입니다. 결괏값의 순서는 aws에 있는 어웨이터블의 순서와 일치합니다.

return_exceptions가 False(기본값)면, 첫 번째 발생한 예외가 gather()를 기다리는 태스크로 즉시 전파됩니다. aws 시퀀스의 다른 어웨이터블은 취소되지 않고 계속 실행됩니다.

return_exceptions가 True면, 예외는 성공적인 결과처럼 처리되고, 결과 리스트에 집계됩니다.

gather()가 취소되면, 모든 제출된 (아직 완료되지 않은) 어웨이터블도 취소됩니다.

aws 시퀀스의 Task나 Future가 취소되면, 그것이 CancelledError를 일으킨 것처럼 처리됩니다 – 이때 gather() 호출은 취소되지 않습니다. 이것은 제출된 태스크/퓨처 하나를 취소하는 것이 다른 태스크/퓨처를 취소하게 되는 것을 막기 위한 것입니다.

참고

A new alternative to create and run tasks concurrently and wait for their completion is asyncio.TaskGroup. TaskGroup provides stronger safety guarantees than gather for scheduling a nesting of subtasks: if a task (or a subtask, a task scheduled by a task) raises an exception, TaskGroup will, while gather will not, cancel the remaining scheduled tasks).

예:

import asyncio

async def factorial(name, number):
    f = 1
    for i in range(2, number + 1):
        print(f"Task {name}: Compute factorial({number}), currently i={i}...")
        await asyncio.sleep(1)
        f *= i
    print(f"Task {name}: factorial({number}) = {f}")
    return f

async def main():
    # Schedule three calls *concurrently*:
    L = await asyncio.gather(
        factorial("A", 2),
        factorial("B", 3),
        factorial("C", 4),
    )
    print(L)

asyncio.run(main())

# Expected output:
#
#     Task A: Compute factorial(2), currently i=2...
#     Task B: Compute factorial(3), currently i=2...
#     Task C: Compute factorial(4), currently i=2...
#     Task A: factorial(2) = 2
#     Task B: Compute factorial(3), currently i=3...
#     Task C: Compute factorial(4), currently i=3...
#     Task B: factorial(3) = 6
#     Task C: Compute factorial(4), currently i=4...
#     Task C: factorial(4) = 24
#     [2, 6, 24]

참고

If return_exceptions is false, cancelling gather() after it has been marked done won’t cancel any submitted awaitables. For instance, gather can be marked done after propagating an exception to the caller, therefore, calling gather.cancel() after catching an exception (raised by one of the awaitables) from gather won’t cancel any other awaitables.

버전 3.7에서 변경: gather 자체가 취소되면, return_exceptions와 관계없이 취소가 전파됩니다.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.10부터 폐지됨: Deprecation warning is emitted if no positional arguments are provided or not all positional arguments are Future-like objects and there is no running event loop.

Eager Task Factory

asyncio.eager_task_factory(loop, coro, *, name=None, context=None)

A task factory for eager task execution.

When using this factory (via loop.set_task_factory(asyncio.eager_task_factory)), coroutines begin execution synchronously during Task construction. Tasks are only scheduled on the event loop if they block. This can be a performance improvement as the overhead of loop scheduling is avoided for coroutines that complete synchronously.

A common example where this is beneficial is coroutines which employ caching or memoization to avoid actual I/O when possible.

참고

Immediate execution of the coroutine is a semantic change. If the coroutine returns or raises, the task is never scheduled to the event loop. If the coroutine execution blocks, the task is scheduled to the event loop. This change may introduce behavior changes to existing applications. For example, the application’s task execution order is likely to change.

Added in version 3.12.

asyncio.create_eager_task_factory(custom_task_constructor)

Create an eager task factory, similar to eager_task_factory(), using the provided custom_task_constructor when creating a new task instead of the default Task.

custom_task_constructor must be a callable with the signature matching the signature of Task.__init__. The callable must return a asyncio.Task-compatible object.

This function returns a callable intended to be used as a task factory of an event loop via loop.set_task_factory(factory)).

Added in version 3.12.

취소로부터 보호하기

awaitable asyncio.shield(aw)

어웨이터블 객체를 취소로부터 보호합니다.

aw가 코루틴이면 자동으로 태스크로 예약됩니다.

다음 문장:

task = asyncio.create_task(something())
res = await shield(task)

은 다음과 동등합니다:

res = await something()

단, 그것을 포함하는 코루틴이 취소되면, something()에서 실행 중인 태스크는 취소되지 않는다는 것만 예외입니다. something()의 관점에서는, 취소가 일어나지 않았습니다. 호출자는 여전히 취소되었고, “await” 표현식은 여전히 CancelledError를 발생시킵니다.

something()가 다른 수단(즉, 그 안에서 스스로)에 의해 취소되면, shield()도 취소됩니다.

취소를 완전히 무시하려면(권장되지 않습니다), 다음과 같이 shield() 함수를 try/except 절과 결합해야 합니다:

task = asyncio.create_task(something())
try:
    res = await shield(task)
except CancelledError:
    res = None

중요

Save a reference to tasks passed to this function, to avoid a task disappearing mid-execution. The event loop only keeps weak references to tasks. A task that isn’t referenced elsewhere may get garbage collected at any time, even before it’s done.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.10부터 폐지됨: Deprecation warning is emitted if aw is not Future-like object and there is no running event loop.

시간제한

asyncio.timeout(delay)

Return an asynchronous context manager that can be used to limit the amount of time spent waiting on something.

delay can either be None, or a float/int number of seconds to wait. If delay is None, no time limit will be applied; this can be useful if the delay is unknown when the context manager is created.

In either case, the context manager can be rescheduled after creation using Timeout.reschedule().

예:

async def main():
    async with asyncio.timeout(10):
        await long_running_task()

If long_running_task takes more than 10 seconds to complete, the context manager will cancel the current task and handle the resulting asyncio.CancelledError internally, transforming it into a TimeoutError which can be caught and handled.

참고

The asyncio.timeout() context manager is what transforms the asyncio.CancelledError into a TimeoutError, which means the TimeoutError can only be caught outside of the context manager.

Example of catching TimeoutError:

async def main():
    try:
        async with asyncio.timeout(10):
            await long_running_task()
    except TimeoutError:
        print("The long operation timed out, but we've handled it.")

    print("This statement will run regardless.")

The context manager produced by asyncio.timeout() can be rescheduled to a different deadline and inspected.

class asyncio.Timeout(when)

An asynchronous context manager for cancelling overdue coroutines.

when should be an absolute time at which the context should time out, as measured by the event loop’s clock:

If when is None, the timeout will never trigger.

If when < loop.time(), the timeout will trigger on the next iteration of the event loop.

when() → float | None

Return the current deadline, or None if the current deadline is not set.

reschedule(when: float | None)

Reschedule the timeout.

expired() → bool

Return whether the context manager has exceeded its deadline (expired).

예:

async def main():
    try:
        # We do not know the timeout when starting, so we pass ``None``.
        async with asyncio.timeout(None) as cm:
            # We know the timeout now, so we reschedule it.
            new_deadline = get_running_loop().time() + 10
            cm.reschedule(new_deadline)

            await long_running_task()
    except TimeoutError:
        pass

    if cm.expired():
        print("Looks like we haven't finished on time.")

Timeout context managers can be safely nested.

Added in version 3.11.

asyncio.timeout_at(when)

Similar to asyncio.timeout(), except when is the absolute time to stop waiting, or None.

예:

async def main():
    loop = get_running_loop()
    deadline = loop.time() + 20
    try:
        async with asyncio.timeout_at(deadline):
            await long_running_task()
    except TimeoutError:
        print("The long operation timed out, but we've handled it.")

    print("This statement will run regardless.")

Added in version 3.11.

coroutine asyncio.wait_for(aw, timeout)

aw 어웨이터블이 제한된 시간 내에 완료될 때까지 기다립니다.

aw가 코루틴이면 자동으로 태스크로 예약됩니다.

timeout은 None 또는 대기할 float 나 int 초 수입니다. timeout이 None이면 퓨처가 완료될 때까지 블록합니다.

If a timeout occurs, it cancels the task and raises TimeoutError.

태스크 취소를 피하려면, shield()로 감싸십시오.

이 함수는 퓨처가 실제로 취소될 때까지 대기하므로, 총 대기 시간이 timeout을 초과할 수 있습니다. 취소하는 동안 예외가 발생하면, 전파됩니다.

대기가 취소되면, 퓨처 aw도 취소됩니다.

예:

async def eternity():
    # Sleep for one hour
    await asyncio.sleep(3600)
    print('yay!')

async def main():
    # Wait for at most 1 second
    try:
        await asyncio.wait_for(eternity(), timeout=1.0)
    except TimeoutError:
        print('timeout!')

asyncio.run(main())

# Expected output:
#
#     timeout!

버전 3.7에서 변경: When aw is cancelled due to a timeout, wait_for waits for aw to be cancelled. Previously, it raised TimeoutError immediately.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Raises TimeoutError instead of asyncio.TimeoutError.

대기 프리미티브

coroutine asyncio.wait(aws, *, timeout=None, return_when=ALL_COMPLETED)

Run Future and Task instances in the aws iterable concurrently and block until the condition specified by return_when.

aws 이터러블은 비어있을 수 없습니다.

두 집합의 태스크/퓨처를 반환합니다: (done, pending).

사용법:

done, pending = await asyncio.wait(aws)

timeout(float나 int)을 지정하면, 반환하기 전에 대기할 최대 시간(초)을 제어할 수 있습니다.

Note that this function does not raise TimeoutError. Futures or Tasks that aren’t done when the timeout occurs are simply returned in the second set.

return_when는 이 함수가 언제 반환해야 하는지 나타냅니다. 다음 상수 중 하나여야 합니다:

상수

설명

asyncio.FIRST_COMPLETED

퓨처가 하나라도 끝나거나 취소될 때 함수가 반환됩니다.

asyncio.FIRST_EXCEPTION

The function will return when any future finishes by raising an exception. If no future raises an exception then it is equivalent to ALL_COMPLETED.

asyncio.ALL_COMPLETED

모든 퓨처가 끝나거나 취소되면 함수가 반환됩니다.

wait_for()와 달리, wait()는 시간 초과가 발생할 때 퓨처를 취소하지 않습니다.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Passing coroutine objects to wait() directly is forbidden.

버전 3.12에서 변경: Added support for generators yielding tasks.

asyncio.as_completed(aws, *, timeout=None)

Run awaitable objects in the aws iterable concurrently. The returned object can be iterated to obtain the results of the awaitables as they finish.

The object returned by as_completed() can be iterated as an asynchronous iterator or a plain iterator. When asynchronous iteration is used, the originally-supplied awaitables are yielded if they are tasks or futures. This makes it easy to correlate previously-scheduled tasks with their results. Example:

ipv4_connect = create_task(open_connection("127.0.0.1", 80))
ipv6_connect = create_task(open_connection("::1", 80))
tasks = [ipv4_connect, ipv6_connect]

async for earliest_connect in as_completed(tasks):
    # earliest_connect is done. The result can be obtained by
    # awaiting it or calling earliest_connect.result()
    reader, writer = await earliest_connect

    if earliest_connect is ipv6_connect:
        print("IPv6 connection established.")
    else:
        print("IPv4 connection established.")

During asynchronous iteration, implicitly-created tasks will be yielded for supplied awaitables that aren’t tasks or futures.

When used as a plain iterator, each iteration yields a new coroutine that returns the result or raises the exception of the next completed awaitable. This pattern is compatible with Python versions older than 3.13:

ipv4_connect = create_task(open_connection("127.0.0.1", 80))
ipv6_connect = create_task(open_connection("::1", 80))
tasks = [ipv4_connect, ipv6_connect]

for next_connect in as_completed(tasks):
    # next_connect is not one of the original task objects. It must be
    # awaited to obtain the result value or raise the exception of the
    # awaitable that finishes next.
    reader, writer = await next_connect

A TimeoutError is raised if the timeout occurs before all awaitables are done. This is raised by the async for loop during asynchronous iteration or by the coroutines yielded during plain iteration.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.10부터 폐지됨: Deprecation warning is emitted if not all awaitable objects in the aws iterable are Future-like objects and there is no running event loop.

버전 3.12에서 변경: Added support for generators yielding tasks.

버전 3.13에서 변경: The result can now be used as either an asynchronous iterator or as a plain iterator (previously it was only a plain iterator).

스레드에서 실행하기

coroutine asyncio.to_thread(func, /, *args, **kwargs)

별도의 스레드에서 func 함수를 비동기적으로 실행합니다.

이 함수에 제공된 모든 *args 와 **kwargs 는 func로 직접 전달됩니다. 또한, 현재 contextvars.Context가 전파되어, 이벤트 루프 스레드의 컨텍스트 변수가 별도의 스레드에서 액세스 될 수 있습니다.

func의 최종 결과를 얻기 위해 어웨이트 할 수 있는 코루틴을 반환합니다.

This coroutine function is primarily intended to be used for executing IO-bound functions/methods that would otherwise block the event loop if they were run in the main thread. For example:

def blocking_io():
    print(f"start blocking_io at {time.strftime('%X')}")
    # Note that time.sleep() can be replaced with any blocking
    # IO-bound operation, such as file operations.
    time.sleep(1)
    print(f"blocking_io complete at {time.strftime('%X')}")

async def main():
    print(f"started main at {time.strftime('%X')}")

    await asyncio.gather(
        asyncio.to_thread(blocking_io),
        asyncio.sleep(1))

    print(f"finished main at {time.strftime('%X')}")

asyncio.run(main())

# Expected output:
#
# started main at 19:50:53
# start blocking_io at 19:50:53
# blocking_io complete at 19:50:54
# finished main at 19:50:54

Directly calling blocking_io() in any coroutine would block the event loop for its duration, resulting in an additional 1 second of run time. Instead, by using asyncio.to_thread(), we can run it in a separate thread without blocking the event loop.

참고

Due to the GIL, asyncio.to_thread() can typically only be used to make IO-bound functions non-blocking. However, for extension modules that release the GIL or alternative Python implementations that don’t have one, asyncio.to_thread() can also be used for CPU-bound functions.

Added in version 3.9.

다른 스레드에서 예약하기

asyncio.run_coroutine_threadsafe(coro, loop)

주어진 이벤트 루프에 코루틴을 제출합니다. 스레드 안전합니다.

다른 OS 스레드에서 결과를 기다리는 concurrent.futures.Future를 반환합니다.

이 함수는 이벤트 루프가 실행 중인 스레드가 아닌, 다른 OS 스레드에서 호출하기 위한 것입니다. 예:

# Create a coroutine
coro = asyncio.sleep(1, result=3)

# Submit the coroutine to a given loop
future = asyncio.run_coroutine_threadsafe(coro, loop)

# Wait for the result with an optional timeout argument
assert future.result(timeout) == 3

코루틴에서 예외가 발생하면, 반환된 Future에 통지됩니다. 또한, 이벤트 루프에서 태스크를 취소하는 데 사용할 수 있습니다:

try:
    result = future.result(timeout)
except TimeoutError:
    print('The coroutine took too long, cancelling the task...')
    future.cancel()
except Exception as exc:
    print(f'The coroutine raised an exception: {exc!r}')
else:
    print(f'The coroutine returned: {result!r}')

설명서의 동시성과 다중 스레드 절을 참조하십시오.

다른 asyncio 함수와 달리, 이 함수는 loop 인자가 명시적으로 전달되어야 합니다.

Added in version 3.5.1.

인트로스펙션

asyncio.current_task(loop=None)

현재 실행 중인 Task 인스턴스를 반환하거나 태스크가 실행되고 있지 않으면 None을 반환합니다.

loop가 None이면, 현재 루프를 가져오는 데 get_running_loop()가 사용됩니다.

Added in version 3.7.

asyncio.all_tasks(loop=None)

루프에 의해 실행되는 아직 완료되지 않은 Task 객체 집합을 반환합니다.

loop가 None이면, 현재 루프를 가져오는 데 get_running_loop()가 사용됩니다.

Added in version 3.7.

asyncio.iscoroutine(obj)

Return True if obj is a coroutine object.

Added in version 3.4.

Task 객체

class asyncio.Task(coro, *, loop=None, name=None, context=None, eager_start=False)

파이썬 코루틴을 실행하는 퓨처류 객체입니다. 스레드 안전하지 않습니다.

태스크는 이벤트 루프에서 코루틴을 실행하는 데 사용됩니다. 만약 코루틴이 Future를 기다리고 있다면, 태스크는 코루틴의 실행을 일시 중지하고 Future의 완료를 기다립니다. 퓨처가 완료되면, 감싸진 코루틴의 실행이 다시 시작됩니다.

이벤트 루프는 협업 스케줄링을 사용합니다: 이벤트 루프는 한 번에 하나의 Task를 실행합니다. Task가 Future의 완료를 기다리는 동안, 이벤트 루프는 다른 태스크, 콜백을 실행하거나 IO 연산을 수행합니다.

테스크를 만들려면 고수준 asyncio.create_task() 함수를 사용하거나, 저수준 loop.create_task() 나 ensure_future() 함수를 사용하십시오. 태스크의 인스턴스를 직접 만드는 것은 권장되지 않습니다.

실행 중인 Task를 취소하려면 cancel() 메서드를 사용하십시오. 이를 호출하면 태스크가 감싼 코루틴으로 CancelledError 예외를 던집니다. 코루틴이 취소 중에 Future 객체를 기다리고 있으면, Future 객체가 취소됩니다.

cancelled()는 태스크가 취소되었는지 확인하는 데 사용할 수 있습니다. 이 메서드는 감싼 코루틴이 CancelledError 예외를 억제하지 않고 실제로 취소되었으면 True를 반환합니다.

asyncio.Task는 Future.set_result()와 Future.set_exception()을 제외한 모든 API를 Future에서 상속받습니다.

An optional keyword-only context argument allows specifying a custom contextvars.Context for the coro to run in. If no context is provided, the Task copies the current context and later runs its coroutine in the copied context.

An optional keyword-only eager_start argument allows eagerly starting the execution of the asyncio.Task at task creation time. If set to True and the event loop is running, the task will start executing the coroutine immediately, until the first time the coroutine blocks. If the coroutine returns or raises without blocking, the task will be finished eagerly and will skip scheduling to the event loop.

버전 3.7에서 변경: contextvars 모듈에 대한 지원이 추가되었습니다.

버전 3.8에서 변경: Added the name parameter.

버전 3.10부터 폐지됨: Deprecation warning is emitted if loop is not specified and there is no running event loop.

버전 3.11에서 변경: Added the context parameter.

버전 3.12에서 변경: Added the eager_start parameter.

done()

Task가 완료(done)되었으면 True를 반환합니다.

감싼 코루틴이 값을 반환하거나 예외를 일으키거나, Task가 취소되면 Task는 완료(done)됩니다.

result()

Task의 결과를 반환합니다.

Task가 완료(done)되었으면 감싼 코루틴의 결과가 반환됩니다 (또는 코루틴이 예외를 발생시켰으면 해당 예외가 다시 발생합니다).

태스크가 취소(cancelled)되었으면, 이 메서드는 CancelledError 예외를 발생시킵니다.

If the Task’s result isn’t yet available, this method raises an InvalidStateError exception.

exception()

Task의 예외를 반환합니다.

감싼 코루틴이 예외를 발생시키면, 그 예외가 반환됩니다. 감싼 코루틴이 정상적으로 반환되면, 이 메서드는 None을 반환합니다.

태스크가 취소(cancelled)되었으면, 이 메서드는 CancelledError 예외를 발생시킵니다.

태스크가 아직 완료(done)되지 않았으면, 이 메서드는 InvalidStateError 예외를 발생시킵니다.

add_done_callback(callback, *, context=None)

태스크가 완료(done)될 때 실행할 콜백을 추가합니다.

이 메서드는 저수준 콜백 기반 코드에서만 사용해야 합니다.

자세한 내용은 Future.add_done_callback() 설명서를 참조하십시오.

remove_done_callback(callback)

콜백 목록에서 callback을 제거합니다.

이 메서드는 저수준 콜백 기반 코드에서만 사용해야 합니다.

자세한 내용은 Future.remove_done_callback() 설명서를 참조하십시오.

get_stack(*, limit=None)

이 Task의 스택 프레임 리스트를 돌려줍니다.

감싼 코루틴이 완료되지 않았으면, 일시 정지된 곳의 스택을 반환합니다. 코루틴이 성공적으로 완료되었거나 취소되었으면 빈 리스트가 반환됩니다. 코루틴이 예외로 종료되었으면, 이것은 트레이스백 프레임의 리스트를 반환합니다.

프레임은 항상 가장 오래된 것부터 순서대로 정렬됩니다.

일시 정지된 코루틴에서는 하나의 스택 프레임만 반환됩니다.

선택적 limit 인자는 반환할 최대 프레임 수를 설정합니다; 기본적으로 사용 가능한 모든 프레임이 반환됩니다. 반환되는 리스트의 순서는 스택과 트레이스백 중 어느 것이 반환되는지에 따라 다릅니다: 스택은 최신 프레임이 반환되지만, 트레이스백은 가장 오래된 프레임이 반환됩니다. (이는 traceback 모듈의 동작과 일치합니다.)

print_stack(*, limit=None, file=None)

이 Task의 스택이나 트레이스백을 인쇄합니다.

이것은 get_stack()으로 얻은 프레임에 대해 traceback 모듈과 유사한 출력을 생성합니다.

limit 인자는 get_stack()에 직접 전달됩니다.

The file argument is an I/O stream to which the output is written; by default output is written to sys.stdout.

get_coro()

Task로 싸인 코루틴 객체를 반환합니다.

참고

This will return None for Tasks which have already completed eagerly. See the Eager Task Factory.

Added in version 3.8.

버전 3.12에서 변경: Newly added eager task execution means result may be None.

get_context()

Return the contextvars.Context object associated with the task.

Added in version 3.12.

get_name()

Task의 이름을 반환합니다.

Task에 명시적으로 이름이 지정되지 않으면, 기본 asyncio Task 구현은 인스턴스화 중에 기본 이름을 생성합니다.

Added in version 3.8.

set_name(value)

Task의 이름을 설정합니다.

value 인자는 모든 객체가 될 수 있으며, 문자열로 변환됩니다.

기본 Task 구현에서, 이름은 태스크 객체의 repr() 출력에 표시됩니다.

Added in version 3.8.

cancel(msg=None)

Task 취소를 요청합니다.

이벤트 루프의 다음 사이클에서 감싼 코루틴으로 CancelledError 예외를 던져넣도록 합니다.

The coroutine then has a chance to clean up or even deny the request by suppressing the exception with a try … … except CancelledError … finally block. Therefore, unlike Future.cancel(), Task.cancel() does not guarantee that the Task will be cancelled, although suppressing cancellation completely is not common and is actively discouraged. Should the coroutine nevertheless decide to suppress the cancellation, it needs to call Task.uncancel() in addition to catching the exception.

버전 3.9에서 변경: Added the msg parameter.

버전 3.11에서 변경: The msg parameter is propagated from cancelled task to its awaiter.

다음 예는 코루틴이 취소 요청을 가로채는 방법을 보여줍니다:

async def cancel_me():
    print('cancel_me(): before sleep')

    try:
        # Wait for 1 hour
        await asyncio.sleep(3600)
    except asyncio.CancelledError:
        print('cancel_me(): cancel sleep')
        raise
    finally:
        print('cancel_me(): after sleep')

async def main():
    # Create a "cancel_me" Task
    task = asyncio.create_task(cancel_me())

    # Wait for 1 second
    await asyncio.sleep(1)

    task.cancel()
    try:
        await task
    except asyncio.CancelledError:
        print("main(): cancel_me is cancelled now")

asyncio.run(main())

# Expected output:
#
#     cancel_me(): before sleep
#     cancel_me(): cancel sleep
#     cancel_me(): after sleep
#     main(): cancel_me is cancelled now

cancelled()

Task가 취소(cancelled)되었으면 True를 반환합니다.

Task는 cancel()로 취소가 요청되고 감싼 코루틴이 자신에게 전달된 CancelledError 예외를 확산할 때 최소(cancelled)됩니다.

uncancel()

Decrement the count of cancellation requests to this Task.

Returns the remaining number of cancellation requests.

Note that once execution of a cancelled task completed, further calls to uncancel() are ineffective.

Added in version 3.11.

This method is used by asyncio’s internals and isn’t expected to be used by end-user code. In particular, if a Task gets successfully uncancelled, this allows for elements of structured concurrency like Task Groups and asyncio.timeout() to continue running, isolating cancellation to the respective structured block. For example:

async def make_request_with_timeout():
    try:
        async with asyncio.timeout(1):
            # Structured block affected by the timeout:
            await make_request()
            await make_another_request()
    except TimeoutError:
        log("There was a timeout")
    # Outer code not affected by the timeout:
    await unrelated_code()

While the block with make_request() and make_another_request() might get cancelled due to the timeout, unrelated_code() should continue running even in case of the timeout. This is implemented with uncancel(). TaskGroup context managers use uncancel() in a similar fashion.

If end-user code is, for some reason, suppressing cancellation by catching CancelledError, it needs to call this method to remove the cancellation state.

When this method decrements the cancellation count to zero, the method checks if a previous cancel() call had arranged for CancelledError to be thrown into the task. If it hasn’t been thrown yet, that arrangement will be rescinded (by resetting the internal _must_cancel flag).

버전 3.13에서 변경: Changed to rescind pending cancellation requests upon reaching zero.

cancelling()

Return the number of pending cancellation requests to this Task, i.e., the number of calls to cancel() less the number of uncancel() calls.

Note that if this number is greater than zero but the Task is still executing, cancelled() will still return False. This is because this number can be lowered by calling uncancel(), which can lead to the task not being cancelled after all if the cancellation requests go down to zero.

This method is used by asyncio’s internals and isn’t expected to be used by end-user code. See uncancel() for more details.

Added in version 3.11.

스트림

소스 코드: Lib/asyncio/streams.py [https://github.com/python/cpython/tree/main/Lib/asyncio/streams.py]

스트림은 네트워크 연결로 작업하기 위해, async/await에서 사용할 수 있는 고수준 프리미티브입니다. 스트림은 콜백이나 저수준 프로토콜과 트랜스포트를 사용하지 않고 데이터를 송수신할 수 있게 합니다.

다음은 asyncio 스트림을 사용하여 작성된 TCP 메아리 클라이언트의 예입니다:

import asyncio

async def tcp_echo_client(message):
    reader, writer = await asyncio.open_connection(
        '127.0.0.1', 8888)

    print(f'Send: {message!r}')
    writer.write(message.encode())
    await writer.drain()

    data = await reader.read(100)
    print(f'Received: {data.decode()!r}')

    print('Close the connection')
    writer.close()
    await writer.wait_closed()

asyncio.run(tcp_echo_client('Hello World!'))

아래의 예제 절도 참조하십시오.

스트림 함수

다음 최상위 asyncio 함수를 사용하여 스트림을 만들고 작업할 수 있습니다.:

coroutine asyncio.open_connection(host=None, port=None, *, limit=None, ssl=None, family=0, proto=0, flags=0, sock=None, local_addr=None, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, happy_eyeballs_delay=None, interleave=None)

네트워크 연결을 만들고 (reader, writer) 객체 쌍을 반환합니다.

반환된 reader 와 writer 객체는 StreamReader 와 StreamWriter 클래스의 인스턴스입니다.

limit는 반환된 StreamReader 인스턴스가 사용하는 버퍼 크기 한계를 결정합니다. 기본적으로 limit는 64KiB로 설정됩니다.

나머지 인자는 loop.create_connection()로 직접 전달됩니다.

참고

The sock argument transfers ownership of the socket to the StreamWriter created. To close the socket, call its close() method.

버전 3.7에서 변경: Added the ssl_handshake_timeout parameter.

버전 3.8에서 변경: Added the happy_eyeballs_delay and interleave parameters.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

coroutine asyncio.start_server(client_connected_cb, host=None, port=None, *, limit=None, family=socket.AF_UNSPEC, flags=socket.AI_PASSIVE, sock=None, backlog=100, ssl=None, reuse_address=None, reuse_port=None, keep_alive=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, start_serving=True)

소켓 서버를 시작합니다.

새 클라이언트 연결이 만들어질 때마다 client_connected_cb 콜백이 호출됩니다. 이 콜백은 두 개의 인자로 (reader, writer) 쌍을 받는데, StreamReader 와 StreamWriter 클래스의 인스턴스입니다.

client_connected_cb는 일반 콜러블이나 코루틴 함수 일 수 있습니다; 코루틴 함수면, 자동으로 Task로 예약됩니다.

limit는 반환된 StreamReader 인스턴스가 사용하는 버퍼 크기 한계를 결정합니다. 기본적으로 limit는 64KiB로 설정됩니다.

나머지 인자는 loop.create_server()로 직접 전달됩니다.

참고

The sock argument transfers ownership of the socket to the server created. To close the socket, call the server’s close() method.

버전 3.7에서 변경: Added the ssl_handshake_timeout and start_serving parameters.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

버전 3.13에서 변경: Added the keep_alive parameter.

유닉스 소켓

coroutine asyncio.open_unix_connection(path=None, *, limit=None, ssl=None, sock=None, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

유닉스 소켓 연결을 만들고 (reader, writer) 쌍을 반환합니다.

open_connection()과 비슷하지만, 유닉스 소켓에서 작동합니다.

loop.create_unix_connection()의 설명서도 참조하십시오.

참고

The sock argument transfers ownership of the socket to the StreamWriter created. To close the socket, call its close() method.

Availability: Unix.

버전 3.7에서 변경: Added the ssl_handshake_timeout parameter. The path parameter can now be a path-like object

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

coroutine asyncio.start_unix_server(client_connected_cb, path=None, *, limit=None, sock=None, backlog=100, ssl=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, start_serving=True)

유닉스 소켓 서버를 시작합니다.

start_server()와 비슷하지만, 유닉스 소켓에서 작동합니다.

loop.create_unix_server()의 설명서도 참조하십시오.

참고

The sock argument transfers ownership of the socket to the server created. To close the socket, call the server’s close() method.

Availability: Unix.

버전 3.7에서 변경: Added the ssl_handshake_timeout and start_serving parameters. The path parameter can now be a path-like object.

버전 3.10에서 변경: Removed the loop parameter.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

StreamReader

class asyncio.StreamReader

Represents a reader object that provides APIs to read data from the IO stream. As an asynchronous iterable, the object supports the async for statement.

StreamReader 객체를 직접 인스턴스로 만드는 것은 권장되지 않습니다. 대신 open_connection()과 start_server()를 사용하십시오.

feed_eof()

Acknowledge the EOF.

coroutine read(n=-1)

Read up to n bytes from the stream.

If n is not provided or set to -1, read until EOF, then return all read bytes. If EOF was received and the internal buffer is empty, return an empty bytes object.

If n is 0, return an empty bytes object immediately.

If n is positive, return at most n available bytes as soon as at least 1 byte is available in the internal buffer. If EOF is received before any byte is read, return an empty bytes object.

coroutine readline()

한 줄을 읽습니다. 여기서 “줄”은 \n로 끝나는 바이트의 시퀀스입니다.

EOF를 수신했고, \n를 찾을 수 없으면, 이 메서드는 부분적으로 읽은 데이터를 반환합니다.

EOF를 수신했고, 내부 버퍼가 비어 있으면 빈 bytes 객체를 반환합니다.

coroutine readexactly(n)

정확히 n 바이트를 읽습니다.

n 바이트를 읽기 전에 EOF에 도달하면, IncompleteReadError를 일으킵니다. 부분적으로 읽은 데이터를 가져오려면 IncompleteReadError.partial 어트리뷰트를 사용하십시오.

coroutine readuntil(separator=b'\n')

separator가 발견될 때까지 스트림에서 데이터를 읽습니다.

성공하면, 데이터와 separator가 내부 버퍼에서 제거됩니다 (소비됩니다). 반환된 데이터에는 끝에 separator가 포함됩니다.

읽은 데이터의 양이 구성된 스트림 제한을 초과하면 LimitOverrunError 예외가 발생하고, 데이터는 내부 버퍼에 그대로 남아 있으며 다시 읽을 수 있습니다.

완전한 separator가 발견되기 전에 EOF에 도달하면 IncompleteReadError 예외가 발생하고, 내부 버퍼가 재설정됩니다. IncompleteReadError.partial 어트리뷰트에는 separator 일부가 포함될 수 있습니다.

The separator may also be a tuple of separators. In this case the return value will be the shortest possible that has any separator as the suffix. For the purposes of LimitOverrunError, the shortest possible separator is considered to be the one that matched.

Added in version 3.5.2.

버전 3.13에서 변경: The separator parameter may now be a tuple of separators.

at_eof()

버퍼가 비어 있고 feed_eof()가 호출되었으면 True를 반환합니다.

StreamWriter

class asyncio.StreamWriter

IO 스트림에 데이터를 쓰는 API를 제공하는 기록기(writer) 객체를 나타냅니다.

StreamWriter 객체를 직접 인스턴스로 만드는 것은 권장되지 않습니다. 대신 open_connection()과 start_server()를 사용하십시오.

write(data)

이 메서드는 하부 소켓에 data를 즉시 기록하려고 시도합니다. 실패하면, data는 보낼 수 있을 때까지 내부 쓰기 버퍼에 계류됩니다.

이 메서드는 drain() 메서드와 함께 사용해야 합니다:

stream.write(data)
await stream.drain()

writelines(data)

이 메서드는 하부 소켓에 바이트열의 리스트(또는 임의의 이터러블)를 즉시 기록합니다. 실패하면, data는 보낼 수 있을 때까지 내부 쓰기 버퍼에 계류됩니다.

이 메서드는 drain() 메서드와 함께 사용해야 합니다:

stream.writelines(lines)
await stream.drain()

close()

이 메서드는 스트림과 하부 소켓을 닫습니다.

The method should be used, though not mandatory, along with the wait_closed() method:

stream.close()
await stream.wait_closed()

can_write_eof()

하부 트랜스포트가 write_eof() 메서드를 지원하면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

write_eof()

버퍼링 된 쓰기 데이터가 플러시 된 후에 스트림의 쓰기 끝을 닫습니다.

transport

하부 asyncio 트랜스포트를 돌려줍니다.

get_extra_info(name, default=None)

선택적 트랜스포트 정보에 액세스합니다; 자세한 내용은 BaseTransport.get_extra_info()를 참조하십시오.

coroutine drain()

스트림에 기록을 다시 시작하는 것이 적절할 때까지 기다립니다. 예:

writer.write(data)
await writer.drain()

이것은 하부 IO 쓰기 버퍼와 상호 작용하는 흐름 제어 메서드입니다. 버퍼의 크기가 높은 수위에 도달하면, 버퍼 크기가 낮은 수위까지 내려가서 쓰기가 다시 시작될 수 있을 때까지 drain()은 블록합니다. 기다릴 것이 없으면, drain()은 즉시 반환합니다.

coroutine start_tls(sslcontext, *, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

Upgrade an existing stream-based connection to TLS.

Parameters:

sslcontext: a configured instance of SSLContext.

server_hostname: sets or overrides the host name that the target server’s certificate will be matched against.

ssl_handshake_timeout is the time in seconds to wait for the TLS handshake to complete before aborting the connection. 60.0 seconds if None (default).

ssl_shutdown_timeout is the time in seconds to wait for the SSL shutdown to complete before aborting the connection. 30.0 seconds if None (default).

Added in version 3.11.

버전 3.12에서 변경: Added the ssl_shutdown_timeout parameter.

is_closing()

스트림이 닫혔거나 닫히고 있으면 True를 반환합니다.

Added in version 3.7.

coroutine wait_closed()

스트림이 닫힐 때까지 기다립니다.

Should be called after close() to wait until the underlying connection is closed, ensuring that all data has been flushed before e.g. exiting the program.

Added in version 3.7.

예제

스트림을 사용하는 TCP 메아리 클라이언트

asyncio.open_connection() 함수를 사용하는 TCP 메아리 클라이언트:

import asyncio

async def tcp_echo_client(message):
    reader, writer = await asyncio.open_connection(
        '127.0.0.1', 8888)

    print(f'Send: {message!r}')
    writer.write(message.encode())
    await writer.drain()

    data = await reader.read(100)
    print(f'Received: {data.decode()!r}')

    print('Close the connection')
    writer.close()
    await writer.wait_closed()

asyncio.run(tcp_echo_client('Hello World!'))

더 보기

TCP 메아리 클라이언트 프로토콜 예제는 저수준 loop.create_connection() 메서드를 사용합니다.

스트림을 사용하는 TCP 메아리 서버

asyncio.start_server() 함수를 사용하는 TCP 메아리 서버:

import asyncio

async def handle_echo(reader, writer):
    data = await reader.read(100)
    message = data.decode()
    addr = writer.get_extra_info('peername')

    print(f"Received {message!r} from {addr!r}")

    print(f"Send: {message!r}")
    writer.write(data)
    await writer.drain()

    print("Close the connection")
    writer.close()
    await writer.wait_closed()

async def main():
    server = await asyncio.start_server(
        handle_echo, '127.0.0.1', 8888)

    addrs = ', '.join(str(sock.getsockname()) for sock in server.sockets)
    print(f'Serving on {addrs}')

    async with server:
        await server.serve_forever()

asyncio.run(main())

더 보기

TCP 메아리 서버 프로토콜 예제는 loop.create_server() 메서드를 사용합니다.

HTTP 헤더 가져오기

명령 줄로 전달된 URL의 HTTP 헤더를 조회하는 간단한 예제:

import asyncio
import urllib.parse
import sys

async def print_http_headers(url):
    url = urllib.parse.urlsplit(url)
    if url.scheme == 'https':
        reader, writer = await asyncio.open_connection(
            url.hostname, 443, ssl=True)
    else:
        reader, writer = await asyncio.open_connection(
            url.hostname, 80)

    query = (
        f"HEAD {url.path or '/'} HTTP/1.0\r\n"
        f"Host: {url.hostname}\r\n"
        f"\r\n"
    )

    writer.write(query.encode('latin-1'))
    while True:
        line = await reader.readline()
        if not line:
            break

        line = line.decode('latin1').rstrip()
        if line:
            print(f'HTTP header> {line}')

    # Ignore the body, close the socket
    writer.close()
    await writer.wait_closed()

url = sys.argv[1]
asyncio.run(print_http_headers(url))

사용법:

python example.py http://example.com/path/page.html

또는 HTTPS를 사용하면:

python example.py https://example.com/path/page.html

스트림을 사용하여 데이터를 기다리는 열린 소켓 등록

open_connection() 함수를 사용하여 소켓이 데이터를 수신할 때까지 기다리는 코루틴:

import asyncio
import socket

async def wait_for_data():
    # Get a reference to the current event loop because
    # we want to access low-level APIs.
    loop = asyncio.get_running_loop()

    # Create a pair of connected sockets.
    rsock, wsock = socket.socketpair()

    # Register the open socket to wait for data.
    reader, writer = await asyncio.open_connection(sock=rsock)

    # Simulate the reception of data from the network
    loop.call_soon(wsock.send, 'abc'.encode())

    # Wait for data
    data = await reader.read(100)

    # Got data, we are done: close the socket
    print("Received:", data.decode())
    writer.close()
    await writer.wait_closed()

    # Close the second socket
    wsock.close()

asyncio.run(wait_for_data())

더 보기

프로토콜을 사용하여 데이터를 기다리는 열린 소켓 등록 예제는 저수준 프로토콜과 loop.create_connection() 메서드를 사용합니다.

파일 기술자에서 읽기 이벤트를 관찰하기 예제는 저수준 loop.add_reader() 메서드를 사용하여 파일 기술자를 관찰합니다.

동기화 프리미티브

소스 코드: Lib/asyncio/locks.py [https://github.com/python/cpython/tree/main/Lib/asyncio/locks.py]

asyncio 동기화 프리미티브는 threading 모듈의 것과 유사하도록 설계되었습니다만 두 가지 중요한 주의 사항이 있습니다:

asyncio 프리미티브는 스레드 안전하지 않으므로, OS 스레드 동기화(이를 위해서는 threading을 사용하십시오)에 사용하면 안 됩니다.

이러한 동기화 프리미티브의 메서드는 timeout 인자를 받아들이지 않습니다; asyncio.wait_for() 함수를 사용하여 시간제한이 있는 연산을 수행하십시오.

asyncio에는 다음과 같은 기본 동기화 프리미티브가 있습니다:

Lock

Event

Condition

Semaphore

BoundedSemaphore

Barrier

Lock

class asyncio.Lock

asyncio 태스크를 위한 뮤텍스 록을 구현합니다. 스레드 안전하지 않습니다.

asyncio 록은 공유 자원에 대한 독점 액세스를 보장하는 데 사용될 수 있습니다.

Lock을 사용하는 가장 좋은 방법은 async with 문입니다:

lock = asyncio.Lock()

# ... later
async with lock:
    # access shared state

이는 다음과 동등합니다:

lock = asyncio.Lock()

# ... later
await lock.acquire()
try:
    # access shared state
finally:
    lock.release()

버전 3.10에서 변경: Removed the loop parameter.

coroutine acquire()

록을 얻습니다.

이 메서드는 록이 풀림(unlocked)이 될 때까지 기다리고, 잠김(locked)으로 설정한 다음 True를 반환합니다.

잠금이 해제되기를 기다리는 acquire()에서 둘 이상의 코루틴 블록 될 때, 결국 한 개의 코루틴만 진행됩니다.

록을 얻는 것은 공평(fair)합니다: 진행할 코루틴은 록을 기다리기 시작한 첫 번째 코루틴이 됩니다.

release()

록을 반납합니다.

록이 잠김(locked)이면 풀림(unlocked)으로 재설정하고 돌아옵니다.

록이 풀림(unlocked)이면 RuntimeError가 발생합니다.

locked()

록이 잠김(locked)이면 True를 반환합니다.

Event

class asyncio.Event

이벤트 객체. 스레드 안전하지 않습니다.

asyncio 이벤트는 어떤 이벤트가 발생했음을 여러 asyncio 태스크에 알리는 데 사용할 수 있습니다.

Event 객체는 set() 메서드로 참으로 설정하고 clear() 메서드로 거짓으로 재설정할 수 있는 내부 플래그를 관리합니다. wait() 메서드는 플래그가 참으로 설정될 때까지 블록합니다. 플래그는 초기에 거짓으로 설정됩니다.

버전 3.10에서 변경: Removed the loop parameter.

예:

async def waiter(event):
    print('waiting for it ...')
    await event.wait()
    print('... got it!')

async def main():
    # Create an Event object.
    event = asyncio.Event()

    # Spawn a Task to wait until 'event' is set.
    waiter_task = asyncio.create_task(waiter(event))

    # Sleep for 1 second and set the event.
    await asyncio.sleep(1)
    event.set()

    # Wait until the waiter task is finished.
    await waiter_task

asyncio.run(main())

coroutine wait()

이벤트가 설정될 때까지 기다립니다.

이벤트가 설정되었으면 True를 즉시 반환합니다. 그렇지 않으면 다른 태스크가 set()을 호출할 때까지 블록합니다.

set()

이벤트를 설정합니다.

이벤트가 설정되기를 기다리는 모든 태스크는 즉시 깨어납니다.

clear()

이벤트를 지웁니다 (재설정).

이제 wait()를 기다리는 태스크는 set() 메서드가 다시 호출될 때까지 블록 됩니다.

is_set()

이벤트가 설정되면 True를 반환합니다.

Condition

class asyncio.Condition(lock=None)

Condition 객체. 스레드 안전하지 않습니다.

asyncio 조건 프리미티브는 태스크가 어떤 이벤트가 발생하기를 기다린 다음 공유 자원에 독점적으로 액세스하는데 사용할 수 있습니다.

본질에서, Condition 객체는 Event와 Lock의 기능을 결합합니다. 여러 개의 Condition 객체가 하나의 Lock을 공유할 수 있으므로, 공유 자원의 특정 상태에 관심이 있는 다른 태스크 간에 공유 자원에 대한 독점적 액세스를 조정할 수 있습니다.

선택적 lock 인자는 Lock 객체나 None 이어야 합니다. 후자의 경우 새로운 Lock 객체가 자동으로 만들어집니다.

버전 3.10에서 변경: Removed the loop parameter.

Condition을 사용하는 가장 좋은 방법은 async with 문입니다:

cond = asyncio.Condition()

# ... later
async with cond:
    await cond.wait()

이는 다음과 동등합니다:

cond = asyncio.Condition()

# ... later
await cond.acquire()
try:
    await cond.wait()
finally:
    cond.release()

coroutine acquire()

하부 록을 얻습니다.

이 메서드는 하부 록이 풀림(unlocked)이 될 때까지 대기하고, 잠김(locked)으로 설정한 다음 True를 반환합니다.

notify(n=1)

Wake up n tasks (1 by default) waiting on this condition. If fewer than n tasks are waiting they are all awakened.

이 메서드를 호출하기 전에 록을 얻어야 하고, 호출 직후에 반납해야 합니다. 풀린(unlocked) 록으로 호출하면 RuntimeError 에러가 발생합니다.

locked()

하부 록을 얻었으면 True를 돌려줍니다.

notify_all()

이 조건에 대기 중인 모든 태스크를 깨웁니다.

이 메서드는 notify()처럼 작동하지만, 대기 중인 모든 태스크를 깨웁니다.

이 메서드를 호출하기 전에 록을 얻어야 하고, 호출 직후에 반납해야 합니다. 풀린(unlocked) 록으로 호출하면 RuntimeError 에러가 발생합니다.

release()

하부 록을 반납합니다.

풀린 록으로 호출하면, RuntimeError가 발생합니다.

coroutine wait()

알릴 때까지 기다립니다.

이 메서드가 호출될 때 호출하는 태스크가 록을 얻지 않았으면 RuntimeError가 발생합니다.

이 메서드는 하부 잠금을 반납한 다음, notify() 나 notify_all() 호출 때문에 깨어날 때까지 블록합니다. 일단 깨어나면, Condition은 록을 다시 얻고, 이 메서드는 True를 돌려줍니다.

Note that a task may return from this call spuriously, which is why the caller should always re-check the state and be prepared to wait() again. For this reason, you may prefer to use wait_for() instead.

coroutine wait_for(predicate)

predicate가 참이 될 때까지 기다립니다.

The predicate must be a callable which result will be interpreted as a boolean value. The method will repeatedly wait() until the predicate evaluates to true. The final value is the return value.

Semaphore

class asyncio.Semaphore(value=1)

Semaphore 객체. 스레드 안전하지 않습니다.

세마포어는 각 acquire() 호출로 감소하고, 각 release() 호출로 증가하는 내부 카운터를 관리합니다. 카운터는 절대로 0 밑으로 내려갈 수 없습니다; acquire()가 0을 만나면, release()를 호출할 때까지 기다리면서 블록합니다.

선택적 value 인자는 내부 카운터의 초깃값을 제공합니다 (기본적으로 1). 지정된 값이 0보다 작으면 ValueError가 발생합니다.

버전 3.10에서 변경: Removed the loop parameter.

Semaphore를 사용하는 가장 좋은 방법은 async with 문입니다:

sem = asyncio.Semaphore(10)

# ... later
async with sem:
    # work with shared resource

이는 다음과 동등합니다:

sem = asyncio.Semaphore(10)

# ... later
await sem.acquire()
try:
    # work with shared resource
finally:
    sem.release()

coroutine acquire()

세마포어를 얻습니다.

내부 카운터가 0보다 크면, 1 감소시키고 True를 즉시 반환합니다. 0이면, release()가 호출될 때까지 기다린 다음 True를 반환합니다.

locked()

세마포어를 즉시 얻을 수 없으면 True를 반환합니다.

release()

세마포어를 반납하고 내부 카운터를 1 증가시킵니다. 세마포어를 얻기 위해 대기하는 태스크를 깨울 수 있습니다.

BoundedSemaphore와 달리, Semaphore는 acquire() 호출보다 더 많은 release() 호출을 허용합니다.

BoundedSemaphore

class asyncio.BoundedSemaphore(value=1)

제한된 세마포어 객체. 스레드 안전하지 않습니다.

제한된 세마포어는 초기 value 위로 내부 카운터를 증가시키면 release()에서 ValueError를 발생시키는 Semaphore 버전입니다.

버전 3.10에서 변경: Removed the loop parameter.

Barrier

class asyncio.Barrier(parties)

A barrier object. Not thread-safe.

A barrier is a simple synchronization primitive that allows to block until parties number of tasks are waiting on it. Tasks can wait on the wait() method and would be blocked until the specified number of tasks end up waiting on wait(). At that point all of the waiting tasks would unblock simultaneously.

async with can be used as an alternative to awaiting on wait().

The barrier can be reused any number of times.

예:

async def example_barrier():
   # barrier with 3 parties
   b = asyncio.Barrier(3)

   # create 2 new waiting tasks
   asyncio.create_task(b.wait())
   asyncio.create_task(b.wait())

   await asyncio.sleep(0)
   print(b)

   # The third .wait() call passes the barrier
   await b.wait()
   print(b)
   print("barrier passed")

   await asyncio.sleep(0)
   print(b)

asyncio.run(example_barrier())

Result of this example is:

<asyncio.locks.Barrier object at 0x... [filling, waiters:2/3]>
<asyncio.locks.Barrier object at 0x... [draining, waiters:0/3]>
barrier passed
<asyncio.locks.Barrier object at 0x... [filling, waiters:0/3]>

Added in version 3.11.

coroutine wait()

Pass the barrier. When all the tasks party to the barrier have called this function, they are all unblocked simultaneously.

When a waiting or blocked task in the barrier is cancelled, this task exits the barrier which stays in the same state. If the state of the barrier is “filling”, the number of waiting task decreases by 1.

The return value is an integer in the range of 0 to parties-1, different for each task. This can be used to select a task to do some special housekeeping, e.g.:

...
async with barrier as position:
   if position == 0:
      # Only one task prints this
      print('End of *draining phase*')

This method may raise a BrokenBarrierError exception if the barrier is broken or reset while a task is waiting. It could raise a CancelledError if a task is cancelled.

coroutine reset()

Return the barrier to the default, empty state. Any tasks waiting on it will receive the BrokenBarrierError exception.

If a barrier is broken it may be better to just leave it and create a new one.

coroutine abort()

Put the barrier into a broken state. This causes any active or future calls to wait() to fail with the BrokenBarrierError. Use this for example if one of the tasks needs to abort, to avoid infinite waiting tasks.

parties

The number of tasks required to pass the barrier.

n_waiting

The number of tasks currently waiting in the barrier while filling.

broken

A boolean that is True if the barrier is in the broken state.

exception asyncio.BrokenBarrierError

This exception, a subclass of RuntimeError, is raised when the Barrier object is reset or broken.

버전 3.9에서 변경: await lock 이나 yield from lock 및/또는 with 문(with await lock, with (yield from lock))을 사용하여 록을 얻는 것은 제거되었습니다. 대신 async with lock을 사용하십시오.

서브 프로세스

소스 코드: Lib/asyncio/subprocess.py [https://github.com/python/cpython/tree/main/Lib/asyncio/subprocess.py], Lib/asyncio/base_subprocess.py [https://github.com/python/cpython/tree/main/Lib/asyncio/base_subprocess.py]

이 절에서는 서브 프로세스를 만들고 관리하기 위한 고수준 async/await asyncio API에 관해 설명합니다.

다음은 asyncio가 셸 명령을 실행하고 결과를 얻는 방법의 예입니다:

import asyncio

async def run(cmd):
    proc = await asyncio.create_subprocess_shell(
        cmd,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE)

    stdout, stderr = await proc.communicate()

    print(f'[{cmd!r} exited with {proc.returncode}]')
    if stdout:
        print(f'[stdout]\n{stdout.decode()}')
    if stderr:
        print(f'[stderr]\n{stderr.decode()}')

asyncio.run(run('ls /zzz'))

는 다음과 같이 인쇄할 것입니다:

['ls /zzz' exited with 1]
[stderr]
ls: /zzz: No such file or directory

모든 asyncio 서브 프로세스 함수는 비동기이고, asyncio가 이러한 함수로 작업 할 수 있는 많은 도구를 제공하기 때문에, 여러 서브 프로세스를 병렬로 실행하고 감시하기가 쉽습니다. 여러 명령을 동시에 실행하도록 위 예제를 수정하는 것은 아주 간단합니다:

async def main():
    await asyncio.gather(
        run('ls /zzz'),
        run('sleep 1; echo "hello"'))

asyncio.run(main())

예제 하위 절도 참조하십시오.

서브 프로세스 만들기

coroutine asyncio.create_subprocess_exec(program, *args, stdin=None, stdout=None, stderr=None, limit=None, **kwds)

서브 프로세스를 만듭니다.

The limit argument sets the buffer limit for StreamReader wrappers for Process.stdout and Process.stderr (if subprocess.PIPE is passed to stdout and stderr arguments).

Process 인스턴스를 반환합니다.

다른 매개 변수에 관해서는 loop.subprocess_exec()의 설명서를 참조하십시오.

버전 3.10에서 변경: Removed the loop parameter.

coroutine asyncio.create_subprocess_shell(cmd, stdin=None, stdout=None, stderr=None, limit=None, **kwds)

cmd 셸 명령을 실행합니다.

The limit argument sets the buffer limit for StreamReader wrappers for Process.stdout and Process.stderr (if subprocess.PIPE is passed to stdout and stderr arguments).

Process 인스턴스를 반환합니다.

다른 매개 변수에 관해서는 loop.subprocess_shell()의 설명서를 참조하십시오.

중요

셸 주입 [https://en.wikipedia.org/wiki/Shell_injection#Shell_injection] 취약점을 피하고자 모든 공백과 특수 문자를 적절하게 따옴표로 감싸는 것은 응용 프로그램의 책임입니다. shlex.quote() 함수는 셸 명령을 구성하는 데 사용될 문자열의 공백 문자와 특수 셸 문자를 올바르게 이스케이프 하는 데 사용할 수 있습니다.

버전 3.10에서 변경: Removed the loop parameter.

참고

ProactorEventLoop를 쓰면 윈도우에서 서브 프로세스를 사용할 수 있습니다. 자세한 내용은 윈도우에서의 서브 프로세스 지원을 참조하십시오.

더 보기

또한, asyncio에는 서브 프로세스와 함께 작동하는 다음과 같은 저수준 API가 있습니다: 서브 프로세스 트랜스포트 와 서브 프로세스 프로토콜 뿐만 아니라 loop.subprocess_exec(), loop.subprocess_shell(), loop.connect_read_pipe(), loop.connect_write_pipe().

상수

asyncio.subprocess.PIPE

stdin, stdout 또는 stderr 매개 변수로 전달될 수 있습니다.

PIPE가 stdin 인자로 전달되면, Process.stdin 어트리뷰트는 StreamWriter 인스턴스를 가리킵니다.

PIPE가 stdout 이나 stderr 인자로 전달되면, Process.stdout 과 Process.stderr 어트리뷰트는 StreamReader 인스턴스를 가리 킵니다.

asyncio.subprocess.STDOUT

stderr 인자로 사용할 수 있는 특수 값이며, 표준 에러를 표준 출력으로 리디렉션해야 함을 나타냅니다.

asyncio.subprocess.DEVNULL

프로세스 생성 함수의 stdin, stdout 또는 stderr 인자로 사용할 수 있는 특수 값입니다. 특수 파일 os.devnull이 해당 서브 프로세스 스트림에 사용됨을 나타냅니다.

서브 프로세스와 상호 작용하기

create_subprocess_exec() 와 create_subprocess_shell() 함수는 모두 Process 클래스의 인스턴스를 반환합니다. Process는 서브 프로세스와 통신하고 완료를 관찰할 수 있는 고수준 래퍼입니다.

class asyncio.subprocess.Process

create_subprocess_exec() 와 create_subprocess_shell() 함수로 만들어진 OS 프로세스를 감싸는 객체.

이 클래스는 subprocess.Popen 클래스와 비슷한 API를 갖도록 설계되었지만, 주목할만한 차이점이 있습니다:

Popen과 달리, Process 인스턴스에는 poll() 메서드와 동등한 것이 없습니다;

the communicate() and wait() methods don’t have a timeout parameter: use the wait_for() function;

Process.wait() 메서드는 비동기이지만, subprocess.Popen.wait() 메서드는 블로킹 비지 루프(blocking busy loop)로 구현됩니다;

universal_newlines 매개 변수는 지원되지 않습니다.

이 클래스는 스레드 안전하지 않습니다.

서브 프로세스와 스레드 절도 참조하십시오.

coroutine wait()

자식 프로세스가 종료할 때까지 기다립니다.

returncode 어트리뷰트를 설정하고 반환합니다.

참고

이 메서드는 stdout=PIPE 나 stderr=PIPE를 사용하고 자식 프로세스가 너무 많은 출력을 만들면 교착 상태가 될 수 있습니다. 자식 프로세스는 OS 파이프 버퍼가 더 많은 데이터를 받아들이도록 기다리면서 블록 됩니다. 이 조건을 피하고자, 파이프를 사용할 때는 communicate() 메서드를 사용하십시오.

coroutine communicate(input=None)

프로세스와 상호 작용합니다:

데이터를 stdin으로 보냅니다 (input이 None이 아니면);

closes stdin;

EOF에 도달할 때까지 stdout 과 stderr에서 데이터를 읽습니다;

프로세스가 종료할 때까지 기다립니다.

선택적 input 인자는 자식 프로세스로 전송될 데이터(bytes 객체)입니다.

튜플 (stdout_data, stderr_data)를 반환합니다.

input을 stdin에 쓸 때 BrokenPipeError 나 ConnectionResetError 예외가 발생하면, 예외를 무시합니다. 이 조건은 모든 데이터가 stdin에 기록되기 전에 프로세스가 종료할 때 발생합니다.

프로세스의 ‘stdin으로 데이터를 보내려면, 프로세스를 stdin=PIPE로 만들어야 합니다. 마찬가지로, 결과 튜플에서 None 이외의 것을 얻으려면, stdout=PIPE 와/나 stderr=PIPE 인자를 사용하여 프로세스를 만들어야 합니다.

데이터가 메모리에 버퍼링 되므로, 데이터 크기가 크거나 무제한이면 이 메서드를 사용하지 마십시오.

버전 3.12에서 변경: stdin gets closed when input=None too.

send_signal(signal)

시그널 signal를 자식 프로세스로 보냅니다.

참고

On Windows, SIGTERM is an alias for terminate(). CTRL_C_EVENT and CTRL_BREAK_EVENT can be sent to processes started with a creationflags parameter which includes CREATE_NEW_PROCESS_GROUP.

terminate()

자식 프로세스를 중지합니다.

On POSIX systems this method sends SIGTERM to the child process.

On Windows the Win32 API function TerminateProcess() is called to stop the child process.

kill()

Kill the child process.

POSIX 시스템에서 이 메서드는 SIGKILL를 자식 프로세스로 보냅니다.

윈도우에서 이 메서드는 terminate()의 별칭입니다.

stdin

표준 입력 스트림(StreamWriter) 또는 프로세스가 stdin=None으로 만들어졌으면 None.

stdout

표준 출력 스트림(StreamReader) 또는 프로세스가 stdout=None으로 만들어졌으면 None.

stderr

표준 에러 스트림(StreamReader) 또는 프로세스가 stderr=None으로 만들어졌으면 None.

경고

Use the communicate() method rather than process.stdin.write(), await process.stdout.read() or await process.stderr.read(). This avoids deadlocks due to streams pausing reading or writing and blocking the child process.

pid

프로세스 식별 번호 (PID).

create_subprocess_shell() 함수로 만들어진 프로세스의 경우, 이 어트리뷰트는 생성된 셸의 PID입니다.

returncode

프로세스가 종료할 때의 반환 코드.

None 값은 프로세스가 아직 종료하지 않았음을 나타냅니다.

음수 값 -N은 자식이 시그널 N으로 종료되었음을 나타냅니다 (POSIX만 해당).

서브 프로세스와 스레드

표준 asyncio 이벤트 루프는 기본적으로 다른 스레드에서 서브 프로세스를 실행하는 것을 지원합니다.

윈도우에서 서브 프로세스는 ProactorEventLoop(기본값)에서만 제공되며, SelectorEventLoop에는 서브 프로세스 지원이 없습니다.

대체 이벤트 루프 구현에는 나름의 제한 사항이 있을 수 있습니다; 해당 설명서를 참조하십시오.

더 보기

asyncio의 동시성과 다중 스레드 절.

예제

Process 클래스를 사용하여 서브 프로세스를 제어하고 StreamReader 클래스를 사용하여 표준 출력을 읽는 예제.

서브 프로세스는 create_subprocess_exec() 함수로 만듭니다:

import asyncio
import sys

async def get_date():
    code = 'import datetime; print(datetime.datetime.now())'

    # Create the subprocess; redirect the standard output
    # into a pipe.
    proc = await asyncio.create_subprocess_exec(
        sys.executable, '-c', code,
        stdout=asyncio.subprocess.PIPE)

    # Read one line of output.
    data = await proc.stdout.readline()
    line = data.decode('ascii').rstrip()

    # Wait for the subprocess exit.
    await proc.wait()
    return line

date = asyncio.run(get_date())
print(f"Current date: {date}")

저수준 API를 사용하여 작성된 같은 예제도 참조하십시오.

큐

소스 코드: Lib/asyncio/queues.py [https://github.com/python/cpython/tree/main/Lib/asyncio/queues.py]

asyncio 큐는 queue 모듈의 클래스와 유사하도록 설계되었습니다. asyncio 큐는 스레드 안전하지 않지만, async/await 코드에서 사용되도록 설계되었습니다.

asyncio 큐의 메서드에는 timeout 매개 변수가 없습니다; 시간제한이 있는 큐 연산을 하려면 asyncio.wait_for() 함수를 사용하십시오.

아래의 예제 절도 참조하십시오.

Queue

class asyncio.Queue(maxsize=0)

선입 선출 (FIFO) 큐.

maxsize가 0보다 작거나 같으면 큐 크기는 무한합니다. 0보다 큰 정수면, 큐가 maxsize에 도달했을 때 get()이 항목을 제거할 때까지 await put()이 블록합니다.

표준 라이브러리의 스레드를 쓰는 queue와는 달리, 큐의 크기는 항상 알려져 있으며 qsize() 메서드를 호출하여 얻을 수 있습니다.

버전 3.10에서 변경: Removed the loop parameter.

이 클래스는 스레드 안전하지 않습니다.

maxsize

큐에 허용되는 항목 수.

empty()

큐가 비어 있으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

full()

큐에 maxsize 항목이 있으면 True를 반환합니다.

If the queue was initialized with maxsize=0 (the default), then full() never returns True.

coroutine get()

큐에서 항목을 제거하고 반환합니다. 큐가 비어 있으면, 항목이 들어올 때까지 기다립니다.

Raises QueueShutDown if the queue has been shut down and is empty, or if the queue has been shut down immediately.

get_nowait()

항목을 즉시 사용할 수 있으면 항목을 반환하고, 그렇지 않으면 QueueEmpty를 발생시킵니다.

coroutine join()

큐의 모든 항목을 수신하여 처리할 때까지 블록합니다.

완료되지 않은 작업 수는 항목이 큐에 추가될 때마다 증가합니다. 이 수는 소비자 코루틴이 항목을 수신했고 그 항목에 관한 작업이 모두 완료되었음을 나타내는 task_done()를 호출할 때마다 감소합니다. 완료되지 않은 작업 수가 0으로 떨어지면 join()가 블록 해제됩니다.

coroutine put(item)

큐에 항목을 넣습니다. 큐가 가득 차면, 항목을 추가할 빈자리가 생길 때까지 기다립니다.

Raises QueueShutDown if the queue has been shut down.

put_nowait(item)

블록하지 않고 항목을 큐에 넣습니다.

자리가 즉시 나지 않으면, QueueFull를 일으킵니다.

qsize()

큐에 있는 항목 수를 돌려줍니다.

shutdown(immediate=False)

Shut down the queue, making get() and put() raise QueueShutDown.

By default, get() on a shut down queue will only raise once the queue is empty. Set immediate to true to make get() raise immediately instead.

All blocked callers of put() and get() will be unblocked. If immediate is true, a task will be marked as done for each remaining item in the queue, which may unblock callers of join().

Added in version 3.13.

task_done()

이전에 큐에 넣은 작업이 완료되었음을 나타냅니다.

큐 소비자가 사용합니다. 작업을 꺼내는 데 사용된 get() 마다, 뒤따르는 task_done() 호출은 작업에 관한 처리가 완료되었음을 큐에 알려줍니다.

join()이 현재 블록 중이면, 모든 항목이 처리될 때 다시 시작됩니다 (큐에 put()한 모든 항목에 대해 task_done() 호출이 수신되었음을 뜻합니다).

shutdown(immediate=True) calls task_done() for each remaining item in the queue.

큐에 넣은 항목보다 더 많이 호출되면 ValueError를 발생시킵니다.

우선순위 큐

class asyncio.PriorityQueue

Queue의 변형; 우선순위 순서로 항목을 꺼냅니다 (가장 낮은 우선순위가 처음입니다).

엔트리는 일반적으로 (priority_number, data) 형식의 튜플입니다.

LIFO 큐

class asyncio.LifoQueue

가장 최근에 추가된 항목을 먼저 꺼내는 Queue의 변형 (후입 선출).

예외

exception asyncio.QueueEmpty

이 예외는 get_nowait() 메서드가 빈 큐에 호출될 때 발생합니다.

exception asyncio.QueueFull

put_nowait() 메서드가 maxsize에 도달한 큐에 호출될 때 발생하는 예외입니다.

exception asyncio.QueueShutDown

Exception raised when put() or get() is called on a queue which has been shut down.

Added in version 3.13.

예제

큐를 사용하여 여러 동시 태스크로 작업 부하를 분산시킬 수 있습니다:

import asyncio
import random
import time

async def worker(name, queue):
    while True:
        # Get a "work item" out of the queue.
        sleep_for = await queue.get()

        # Sleep for the "sleep_for" seconds.
        await asyncio.sleep(sleep_for)

        # Notify the queue that the "work item" has been processed.
        queue.task_done()

        print(f'{name} has slept for {sleep_for:.2f} seconds')

async def main():
    # Create a queue that we will use to store our "workload".
    queue = asyncio.Queue()

    # Generate random timings and put them into the queue.
    total_sleep_time = 0
    for _ in range(20):
        sleep_for = random.uniform(0.05, 1.0)
        total_sleep_time += sleep_for
        queue.put_nowait(sleep_for)

    # Create three worker tasks to process the queue concurrently.
    tasks = []
    for i in range(3):
        task = asyncio.create_task(worker(f'worker-{i}', queue))
        tasks.append(task)

    # Wait until the queue is fully processed.
    started_at = time.monotonic()
    await queue.join()
    total_slept_for = time.monotonic() - started_at

    # Cancel our worker tasks.
    for task in tasks:
        task.cancel()
    # Wait until all worker tasks are cancelled.
    await asyncio.gather(*tasks, return_exceptions=True)

    print('====')
    print(f'3 workers slept in parallel for {total_slept_for:.2f} seconds')
    print(f'total expected sleep time: {total_sleep_time:.2f} seconds')

asyncio.run(main())

예외

소스 코드: Lib/asyncio/exceptions.py [https://github.com/python/cpython/tree/main/Lib/asyncio/exceptions.py]

exception asyncio.TimeoutError

A deprecated alias of TimeoutError, raised when the operation has exceeded the given deadline.

버전 3.11에서 변경: This class was made an alias of TimeoutError.

exception asyncio.CancelledError

작업이 취소되었습니다.

이 예외는 asyncio 태스크가 취소될 때 사용자 정의 작업을 수행하기 위해 잡을 수 있습니다. 거의 모든 상황에서 예외를 다시 일으켜야 합니다.

버전 3.8에서 변경: CancelledError is now a subclass of BaseException rather than Exception.

exception asyncio.InvalidStateError

Task 나 Future의 내부 상태가 잘못되었습니다.

이미 결괏값이 설정된 Future 객체에 대해 결괏값을 설정하는 것과 같은 상황에서 발생할 수 있습니다.

exception asyncio.SendfileNotAvailableError

주어진 소켓이나 파일 유형에서는 “sendfile” 시스템 호출을 사용할 수 없습니다.

RuntimeError의 서브 클래스입니다.

exception asyncio.IncompleteReadError

요청한 읽기 작업이 완전히 완료되지 않았습니다.

asyncio 스트림 API가 일으킵니다.

이 예외는 EOFError의 서브 클래스입니다.

expected

기대하는 바이트의 총수 (int).

partial

스트림이 끝나기 전에 읽은 bytes 문자열.

exception asyncio.LimitOverrunError

구분 기호를 찾는 동안 버퍼 크기 제한에 도달했습니다.

asyncio 스트림 API가 일으킵니다.

consumed

소비된 바이트의 총수.

이벤트 루프

소스 코드: Lib/asyncio/events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/events.py], Lib/asyncio/base_events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/base_events.py]

머리말

이벤트 루프는 모든 asyncio 응용 프로그램의 핵심입니다. 이벤트 루프는 비동기 태스크 및 콜백을 실행하고 네트워크 IO 연산을 수행하며 자식 프로세스를 실행합니다.

응용 프로그램 개발자는 일반적으로 asyncio.run()과 같은 고수준의 asyncio 함수를 사용해야 하며, 루프 객체를 참조하거나 메서드를 호출할 필요가 거의 없습니다. 이 절은 주로 이벤트 루프 동작을 세부적으로 제어해야 하는 저수준 코드, 라이브러리 및 프레임워크의 작성자를 대상으로 합니다.

이벤트 루프 얻기

다음 저수준 함수를 사용하여 이벤트 루프를 가져오거나 설정하거나 만들 수 있습니다.:

asyncio.get_running_loop()

현재 OS 스레드에서 실행 중인 이벤트 루프를 반환합니다.

Raise a RuntimeError if there is no running event loop.

This function can only be called from a coroutine or a callback.

Added in version 3.7.

asyncio.get_event_loop()

현재의 이벤트 루프를 가져옵니다.

When called from a coroutine or a callback (e.g. scheduled with call_soon or similar API), this function will always return the running event loop.

If there is no running event loop set, the function will return the result of the get_event_loop_policy().get_event_loop() call.

이 함수는 (특히 사용자 정의 이벤트 루프 정책을 사용할 때) 다소 복잡한 동작을 하므로, 코루틴과 콜백에서 get_event_loop()보다 get_running_loop() 함수를 사용하는 것이 좋습니다.

As noted above, consider using the higher-level asyncio.run() function, instead of using these lower level functions to manually create and close an event loop.

버전 3.14에서 변경: Raises a RuntimeError if there is no current event loop.

asyncio.set_event_loop(loop)

Set loop as the current event loop for the current OS thread.

asyncio.new_event_loop()

Create and return a new event loop object.

get_event_loop(), set_event_loop() 및 new_event_loop() 함수의 동작은 사용자 정의 이벤트 루프 정책 설정에 의해 변경될 수 있음에 유의하십시오.

목차

이 설명서 페이지는 다음과 같은 절로 구성됩니다:

이벤트 루프 메서드 절은 이벤트 루프 API의 레퍼런스 설명서입니다.

콜백 핸들 절은 loop.call_soon() 및 loop.call_later()와 같은 예약 메서드에서 반환된 Handle 및 TimerHandle 인스턴스를 설명합니다.

서버 객체 절은 loop.create_server()와 같은 이벤트 루프 메서드에서 반환되는 형을 설명합니다.

이벤트 루프 구현 절은 SelectorEventLoop 및 ProactorEventLoop 클래스를 설명합니다.

예제 절에서는 일부 이벤트 루프 API로 작업하는 방법을 보여줍니다.

이벤트 루프 메서드

이벤트 루프에는 다음과 같은 저수준 API가 있습니다:

루프 실행 및 중지

콜백 예약하기

지연된 콜백 예약

퓨처와 태스크 만들기

네트워크 연결 열기

네트워크 서버 만들기

파일 전송

TLS 업그레이드

파일 기술자 관찰하기

소켓 객체로 직접 작업하기

DNS

파이프로 작업하기

유닉스 시그널

스레드 또는 프로세스 풀에서 코드를 실행하기

에러 처리 API

디버그 모드 활성화

자식 프로세스 실행하기

루프 실행 및 중지

loop.run_until_complete(future)

future(Future의 인스턴스)가 완료할 때까지 실행합니다.

인자가 코루틴 객체 면, asyncio.Task로 실행되도록 묵시적으로 예약 됩니다.

퓨처의 결과를 반환하거나 퓨처의 예외를 일으킵니다.

loop.run_forever()

stop()가 호출될 때까지 이벤트 루프를 실행합니다.

If stop() is called before run_forever() is called, the loop will poll the I/O selector once with a timeout of zero, run all callbacks scheduled in response to I/O events (and those that were already scheduled), and then exit.

만약 stop() 이 run_forever() 가 실행 중일 때 호출되면, 루프는 현재 걸려있는 콜백들을 실행한 다음 종료합니다. 콜백에 의해 예약되는 새 콜백은 이 경우 실행되지 않습니다; 대신 그것들은 다음에 run_forever()나 run_until_complete()가 호출될 때 실행됩니다.

loop.stop()

이벤트 루프를 중지합니다.

loop.is_running()

이벤트 루프가 현재 실행 중이면 True 를 반환합니다.

loop.is_closed()

이벤트 루프가 닫혔으면 True 를 반환합니다.

loop.close()

이벤트 루프를 닫습니다.

이 함수를 호출할 때 루프는 반드시 실행 중이지 않아야 합니다. 계류 중인 모든 콜백을 버립니다.

이 메서드는 모든 큐를 비우고 실행기를 종료하지만, 실행기가 완료할 때까지 기다리지 않습니다.

이 메서드는 멱등적(itempotent)이고 되돌릴 수 없습니다. 이벤트 루프가 닫힌 후에 다른 메서드를 호출해서는 안 됩니다.

coroutine loop.shutdown_asyncgens()

Schedule all currently open asynchronous generator objects to close with an aclose() call. After calling this method, the event loop will issue a warning if a new asynchronous generator is iterated. This should be used to reliably finalize all scheduled asynchronous generators.

asyncio.run()가 사용될 때 이 함수를 호출할 필요는 없다는 점에 유의하세요.

예:

try:
    loop.run_forever()
finally:
    loop.run_until_complete(loop.shutdown_asyncgens())
    loop.close()

Added in version 3.6.

coroutine loop.shutdown_default_executor(timeout=None)

Schedule the closure of the default executor and wait for it to join all of the threads in the ThreadPoolExecutor. Once this method has been called, using the default executor with loop.run_in_executor() will raise a RuntimeError.

The timeout parameter specifies the amount of time (in float seconds) the executor will be given to finish joining. With the default, None, the executor is allowed an unlimited amount of time.

If the timeout is reached, a RuntimeWarning is emitted and the default executor is terminated without waiting for its threads to finish joining.

참고

Do not call this method when using asyncio.run(), as the latter handles default executor shutdown automatically.

Added in version 3.9.

버전 3.12에서 변경: Added the timeout parameter.

콜백 예약하기

loop.call_soon(callback, *args, context=None)

이벤트 루프의 다음 이터레이션 때 args 인자로 호출할 callback 콜백을 예약합니다.

Return an instance of asyncio.Handle, which can be used later to cancel the callback.

콜백은 등록된 순서대로 호출됩니다. 각 콜백은 정확히 한 번 호출됩니다.

The optional keyword-only context argument specifies a custom contextvars.Context for the callback to run in. Callbacks use the current context when no context is provided.

Unlike call_soon_threadsafe(), this method is not thread-safe.

loop.call_soon_threadsafe(callback, *args, context=None)

A thread-safe variant of call_soon(). When scheduling callbacks from another thread, this function must be used, since call_soon() is not thread-safe.

Raises RuntimeError if called on a loop that’s been closed. This can happen on a secondary thread when the main application is shutting down.

설명서의 동시성과 다중 스레딩 절을 참고하십시오.

버전 3.7에서 변경: context 키워드 전용 매개 변수가 추가되었습니다. 자세한 정보는 PEP 567 [https://peps.python.org/pep-0567/]을 보십시오.

참고

대부분 asyncio 예약 함수는 키워드 인자 전달을 허용하지 않습니다. 그렇게 하려면 functools.partial()을 사용하십시오:

# will schedule "print("Hello", flush=True)"
loop.call_soon(
    functools.partial(print, "Hello", flush=True))

asyncio는 디버그 및 오류 메시지에서 partial 객체를 더욱 잘 표시할 수 있으므로, partial 객체를 사용하는 것이 람다를 사용하는 것보다 편리합니다.

지연된 콜백 예약

이벤트 루프는 콜백 함수가 미래의 어떤 시점에서 호출되도록 예약하는 메커니즘을 제공합니다. 이벤트 루프는 단조 시계를 사용하여 시간을 추적합니다.

loop.call_later(delay, callback, *args, context=None)

지정된 delay 초 (int 또는 float) 뒤에 callback 이 호출되도록 예약합니다.

asyncio.TimerHandle 의 인스턴스가 반환되는데, 콜백을 취소하는 데 사용할 수 있습니다.

callback 은 정확히 한번 호출됩니다. 두 콜백이 정확히 같은 시간에 예약되면, 어떤 것이 먼저 호출되는지는 정의되지 않습니다.

선택적 위치 args 는 호출 될 때 콜백에 전달됩니다. 콜백을 키워드 인자로 호출하고 싶으면 functools.partial() 를 사용하십시오.

선택적인 키워드 전용 context 인자는 callback 을 실행할 사용자 정의 contextvars.Context 를 지정할 수 있게 합니다. context 가 제공되지 않을 때는 현재 컨텍스트가 사용됩니다.

버전 3.7에서 변경: context 키워드 전용 매개 변수가 추가되었습니다. 자세한 정보는 PEP 567 [https://peps.python.org/pep-0567/]을 보십시오.

버전 3.8에서 변경: 파이썬 3.7 및 이전 버전에서 기본 이벤트 루프 구현을 사용할 때, delay는 하루를 초과할 수 없었습니다. 이 문제는 파이썬 3.8에서 수정되었습니다.

loop.call_at(when, callback, *args, context=None)

지정된 절대 타임스탬프 when(int 또는 float)에 callback 이 호출되도록 예약합니다. loop.time() 과 같은 시간 참조를 사용하십시오.

이 메서드의 동작은 call_later()와 같습니다.

asyncio.TimerHandle 의 인스턴스가 반환되는데, 콜백을 취소하는 데 사용할 수 있습니다.

버전 3.7에서 변경: context 키워드 전용 매개 변수가 추가되었습니다. 자세한 정보는 PEP 567 [https://peps.python.org/pep-0567/]을 보십시오.

버전 3.8에서 변경: 파이썬 3.7 및 이전 버전에서 기본 이벤트 루프 구현을 사용할 때, when와 현재 시각의 차이는 하루를 초과할 수 없었습니다. 이 문제는 파이썬 3.8에서 수정되었습니다.

loop.time()

이벤트 루프의 내부 단조 시계에 따라, float 값으로 현재 시각을 반환합니다.

참고

버전 3.8에서 변경: 파이썬 3.7 및 이전 버전에서 제한 시간(상대적인 delay 나 절대적인 when)은 1일을 초과하지 않아야 했습니다. 이 문제는 파이썬 3.8에서 수정되었습니다.

더 보기

asyncio.sleep() 함수.

퓨처와 태스크 만들기

loop.create_future()

이벤트 루프에 연결된 asyncio.Future 객체를 만듭니다.

이것이 asyncio에서 퓨처를 만드는 데 선호되는 방법입니다. 이렇게 하면 제삼자 이벤트 루프가 Future 객체의 다른 구현(더 나은 성능이나 계측(instrumentation))을 제공할 수 있습니다

Added in version 3.5.2.

loop.create_task(coro, *, name=None, context=None)

Schedule the execution of coroutine coro. Return a Task object.

제삼자 이벤트 루프는 상호 운용성을 위해 자신만의 Task 의 서브 클래스를 사용할 수 있습니다. 이 경우, 결과 형은 Task 의 서브 클래스입니다.

name 인자가 제공되고 None이 아니면, Task.set_name()을 사용하여 태스크의 이름으로 설정됩니다.

An optional keyword-only context argument allows specifying a custom contextvars.Context for the coro to run in. The current context copy is created when no context is provided.

버전 3.8에서 변경: Added the name parameter.

버전 3.11에서 변경: Added the context parameter.

loop.set_task_factory(factory)

loop.create_task() 에 의해 사용되는 태스크 팩토리를 설정합니다.

If factory is None the default task factory will be set. Otherwise, factory must be a callable with the signature matching (loop, coro, context=None), where loop is a reference to the active event loop, and coro is a coroutine object. The callable must return a asyncio.Future-compatible object.

loop.get_task_factory()

태스크 팩토리를 반환하거나, 기본값이 사용 중이면 None 을 반환합니다.

네트워크 연결 열기

coroutine loop.create_connection(protocol_factory, host=None, port=None, *, ssl=None, family=0, proto=0, flags=0, sock=None, local_addr=None, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, happy_eyeballs_delay=None, interleave=None, all_errors=False)

주어진 host 와 port로 지정된 주소로의 스트리밍 트랜스포트 연결을 엽니다.

The socket family can be either AF_INET or AF_INET6 depending on host (or the family argument, if provided).

The socket type will be SOCK_STREAM.

protocol_factory 는 반드시 asyncio 프로토콜 구현을 반환하는 콜러블이어야 합니다.

이 메서드는 백그라운드에서 연결을 맺으려고 시도합니다. 성공하면, (transport, protocol) 쌍을 반환합니다.

하부 연산의 시간순 개요는 다음과 같습니다:

연결이 맺어지고, 이를 위한 트랜스포트(transport) 가 만들어집니다.

protocol_factory 가 인자 없이 호출되고, 프로토콜(protocol) 인스턴스를 반환할 것으로 기대됩니다.

프로토콜 인스턴스는 connection_made() 메서드를 호출함으로써 트랜스포트와 연결됩니다.

성공하면 (transport, protocol) 튜플이 반환됩니다.

만들어진 트랜스포트는 구현 의존적인 양방향 스트림입니다.

다른 인자들:

ssl: 주어지고 거짓이 아니면, SSL/TLS 트랜스포트가 만들어집니다 (기본적으로는 평범한 TCP 트랜스포트가 만들어집니다). ssl 이 ssl.SSLContext 객체면, 트랜스포트를 만들 때 이 컨텍스트가 사용됩니다; ssl 이 True 면, ssl.create_default_context() 가 반환하는 기본 컨텍스트가 사용됩니다.

더 보기

SSL/TLS 보안 고려 사항

server_hostname는 대상 서버의 인증서가 일치될 호스트 이름을 설정하거나 대체합니다. ssl이 None이 아닐 때만 전달되어야 합니다. 기본적으로 host 인자의 값이 사용됩니다. host 가 비어 있으면, 기본값이 없고 server_hostname 값을 전달해야 합니다. server_hostname 이 빈 문자열이면, 호스트 이름 일치가 비활성화됩니다 (이것은 심각한 보안 위험으로, 잠재적인 중간자 공격을 허용하게 됩니다).

family, proto, flags 는 host 결정을 위해 getaddrinfo() 에 전달할 선택적 주소 패밀리, 프로토콜, 플래그입니다. 주어지면, 이것들은 모두 해당하는 socket 모듈 상수에 대응하는 정수여야 합니다.

주어지면, happy_eyeballs_delay는 이 연결에 대해 Happy Eyeballs를 활성화합니다. 다음 시도를 병렬로 시작하기 전에, 연결 시도가 완료되기를 기다리는 시간(초)을 나타내는 부동 소수점 숫자여야 합니다. 이것은 RFC 8305 [https://datatracker.ietf.org/doc/html/rfc8305.html]에 정의된 “연결 시도 지연(Connection Attempt Delay)” 입니다. RFC에서 권장하는 적절한 기본값은 0.25(250밀리 초)입니다.

interleave는 호스트 이름이 여러 IP 주소로 해석될 때 주소 재정렬을 제어합니다. 0이거나 지정되지 않으면, 재정렬이 수행되지 않고, 주소는 getaddrinfo()에 의해 반환된 순서대로 시도됩니다. 양의 정수가 지정되면, 주소는 주소 패밀리에 의해 인터리브 되고, 주어진 정수는 RFC 8305 [https://datatracker.ietf.org/doc/html/rfc8305.html]에 정의된 대로 “첫 번째 주소 패밀리 수(First Address Family Count)”로 해석됩니다. 기본값은 happy_eyeballs_delay가 지정되지 않으면 0이고, 지정되면 1입니다.

sock 이 주어지면, 트랜스포트가 사용할, 기존의 이미 연결된 socket.socket 객체여야 합니다. sock 이 주어지면, host, port, family, proto, flags, happy_eyeballs_delay, interleave, local_addr 를 지정해서는 안 됩니다.

참고

The sock argument transfers ownership of the socket to the transport created. To close the socket, call the transport’s close() method.

local_addr, if given, is a (local_host, local_port) tuple used to bind the socket locally. The local_host and local_port are looked up using getaddrinfo(), similarly to host and port.

ssl_handshake_timeout 은 (TLS 연결의 경우) 연결을 중단하기 전에 TLS 핸드 셰이크가 완료될 때까지 대기하는 시간(초)입니다. None (기본값) 이면 60.0 초가 사용됩니다.

ssl_shutdown_timeout is the time in seconds to wait for the SSL shutdown to complete before aborting the connection. 30.0 seconds if None (default).

all_errors determines what exceptions are raised when a connection cannot be created. By default, only a single Exception is raised: the first exception if there is only one or all errors have same message, or a single OSError with the error messages combined. When all_errors is True, an ExceptionGroup will be raised containing all exceptions (even if there is only one).

버전 3.5에서 변경: ProactorEventLoop에 SSL/TLS에 대한 지원이 추가되었습니다.

버전 3.6에서 변경: The socket option socket.TCP_NODELAY is set by default for all TCP connections.

버전 3.7에서 변경: Added the ssl_handshake_timeout parameter.

버전 3.8에서 변경: happy_eyeballs_delay와 interleave 매개 변수가 추가되었습니다.

Happy Eyeballs Algorithm: Success with Dual-Stack Hosts. When a server’s IPv4 path and protocol are working, but the server’s IPv6 path and protocol are not working, a dual-stack client application experiences significant connection delay compared to an IPv4-only client. This is undesirable because it causes the dual-stack client to have a worse user experience. This document specifies requirements for algorithms that reduce this user-visible delay and provides an algorithm.

For more information: https://datatracker.ietf.org/doc/html/rfc6555

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

버전 3.12에서 변경: all_errors was added.

더 보기

open_connection() 함수는 고수준 대안 API입니다. async/await 코드에서 직접 사용할 수 있는 (StreamReader, StreamWriter) 쌍을 반환합니다.

coroutine loop.create_datagram_endpoint(protocol_factory, local_addr=None, remote_addr=None, *, family=0, proto=0, flags=0, reuse_port=None, allow_broadcast=None, sock=None)

데이터 그램 연결을 만듭니다.

The socket family can be either AF_INET, AF_INET6, or AF_UNIX, depending on host (or the family argument, if provided).

The socket type will be SOCK_DGRAM.

protocol_factory 는 반드시 프로토콜 구현을 반환하는 콜러블이어야 합니다.

성공하면 (transport, protocol) 튜플이 반환됩니다.

다른 인자들:

local_addr, if given, is a (local_host, local_port) tuple used to bind the socket locally. The local_host and local_port are looked up using getaddrinfo().

remote_addr 이 주어지면, 소켓을 원격 주소에 연결하는 데 사용되는 (remote_host, remote_port) 튜플입니다. remote_host 와 remote_port 는 getaddrinfo()를 사용하여 조회됩니다.

family, proto, flags 는 host 결정을 위해 getaddrinfo() 에 전달할 선택적 주소 패밀리, 프로토콜, 플래그입니다. 주어지면, 이것들은 모두 해당하는 socket 모듈 상수에 대응하는 정수여야 합니다.

reuse_port tells the kernel to allow this endpoint to be bound to the same port as other existing endpoints are bound to, so long as they all set this flag when being created. This option is not supported on Windows and some Unixes. If the socket.SO_REUSEPORT constant is not defined then this capability is unsupported.

allow_broadcast 는 이 말단이 브로드캐스트 주소로 메시지를 보낼 수 있도록 커널에 알립니다.

sock 은 트랜스포트가 사용할 소켓 객체로, 기존의 이미 연결된 socket.socket 객체를 사용하기 위해 선택적으로 지정할 수 있습니다. 지정되면 local_addr 과 remote_addr 를 생략해야 합니다 (반드시 None 이어야 합니다).

참고

The sock argument transfers ownership of the socket to the transport created. To close the socket, call the transport’s close() method.

UDP 메아리 클라이언트 프로토콜 과 UDP 메아리 서버 프로토콜 예제를 참고하세요.

버전 3.4.4에서 변경: The family, proto, flags, reuse_address, reuse_port, allow_broadcast, and sock parameters were added.

버전 3.8에서 변경: 윈도우에 대한 지원이 추가되었습니다.

버전 3.8.1에서 변경: The reuse_address parameter is no longer supported, as using socket.SO_REUSEADDR poses a significant security concern for UDP. Explicitly passing reuse_address=True will raise an exception.

UID가 다른 여러 프로세스가 SO_REUSEADDR를 사용하여 소켓을 같은 UDP 소켓 주소에 할당하면, 들어오는 패킷이 소켓 간에 무작위로 분산될 수 있습니다.

For supported platforms, reuse_port can be used as a replacement for similar functionality. With reuse_port, socket.SO_REUSEPORT is used instead, which specifically prevents processes with differing UIDs from assigning sockets to the same socket address.

버전 3.11에서 변경: The reuse_address parameter, disabled since Python 3.8.1, 3.7.6 and 3.6.10, has been entirely removed.

coroutine loop.create_unix_connection(protocol_factory, path=None, *, ssl=None, sock=None, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

유닉스 연결을 만듭니다.

The socket family will be AF_UNIX; socket type will be SOCK_STREAM.

성공하면 (transport, protocol) 튜플이 반환됩니다.

path 는 유닉스 도메인 소켓의 이름이며, sock 매개 변수가 지정되지 않으면 필수입니다. 추상 유닉스 소켓, str, bytes, Path 경로가 지원됩니다.

이 메서드의 인자에 관한 정보는 loop.create_connection() 메서드의 설명서를 참조하십시오.

Availability: Unix.

버전 3.7에서 변경: Added the ssl_handshake_timeout parameter. The path parameter can now be a path-like object.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

네트워크 서버 만들기

coroutine loop.create_server(protocol_factory, host=None, port=None, *, family=socket.AF_UNSPEC, flags=socket.AI_PASSIVE, sock=None, backlog=100, ssl=None, reuse_address=None, reuse_port=None, keep_alive=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, start_serving=True)

Create a TCP server (socket type SOCK_STREAM) listening on port of the host address.

Server 객체를 반환합니다.

인자:

protocol_factory 는 반드시 프로토콜 구현을 반환하는 콜러블이어야 합니다.

host 매개 변수는 서버가 리스닝할 위치를 결정하는 여러 형으로 설정할 수 있습니다.:

host가 문자열이면, TCP 서버는 host로 지정된 단일 네트워크 인터페이스에 바인딩 됩니다.

host가 문자열의 시퀀스면, TCP 서버는 시퀀스로 지정된 모든 네트워크 인터페이스에 바인딩 됩니다.

host가 빈 문자열이거나 None이면, 모든 인터페이스가 사용되는 것으로 가정하고, 여러 소켓의 리스트가 반환됩니다 (대체로 IPv4 하나와 IPv6 하나).

The port parameter can be set to specify which port the server should listen on. If 0 or None (the default), a random unused port will be selected (note that if host resolves to multiple network interfaces, a different random port will be selected for each interface).

family can be set to either socket.AF_INET or AF_INET6 to force the socket to use IPv4 or IPv6. If not set, the family will be determined from host name (defaults to AF_UNSPEC).

flags 은 getaddrinfo()를 위한 비트 마스크입니다.

sock 은 기존 소켓 객체를 사용하기 위해 선택적으로 지정할 수 있습니다. 지정되면, host 및 port 는 지정할 수 없습니다.

참고

The sock argument transfers ownership of the socket to the server created. To close the socket, call the server’s close() method.

backlog 는 listen() 으로 전달되는 최대 대기 연결 수 입니다 (기본값은 100).

ssl 을 SSLContext 인스턴스로 설정하면, 들어오는 연결에 TLS를 사용합니다.

reuse_address 는, 일반적인 시간제한이 만료될 때까지 기다리지 않고, TIME_WAIT 상태의 로컬 소켓을 재사용하도록 커널에 알려줍니다. 지정하지 않으면 유닉스에서 자동으로 True 로 설정됩니다.

reuse_port 는 모두 만들 때 이 플래그를 설정하는 한, 이 말단이 다른 기존 말단이 바인드 된 것과 같은 포트에 바인드 되도록 허용하도록 커널에 알려줍니다. 이 옵션은 윈도우에서 지원되지 않습니다.

keep_alive set to True keeps connections active by enabling the periodic transmission of messages.

버전 3.13에서 변경: Added the keep_alive parameter.

ssl_handshake_timeout 은 (TLS 서버의 경우) 연결을 중단하기 전에 TLS 핸드 셰이크가 완료될 때까지 대기하는 시간(초)입니다. None (기본값) 이면 60.0 초가 사용됩니다.

ssl_shutdown_timeout is the time in seconds to wait for the SSL shutdown to complete before aborting the connection. 30.0 seconds if None (default).

start_serving 을 True (기본값) 로 설정하면, 생성된 서버가 즉시 연결을 받아들입니다. False 로 설정되면, 사용자는 서버가 연결을 받기 시작하도록 Server.start_serving() 이나 Server.serve_forever()를 await 해야 합니다.

버전 3.5에서 변경: ProactorEventLoop에 SSL/TLS에 대한 지원이 추가되었습니다.

버전 3.5.1에서 변경: host 매개 변수는 문자열의 시퀀스가 될 수 있습니다.

버전 3.6에서 변경: Added ssl_handshake_timeout and start_serving parameters. The socket option socket.TCP_NODELAY is set by default for all TCP connections.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

더 보기

start_server() 함수는 async/await 코드에서 사용할 수 있는 StreamReader 및 StreamWriter 쌍을 반환하는 고수준의 대체 API입니다.

coroutine loop.create_unix_server(protocol_factory, path=None, *, sock=None, backlog=100, ssl=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None, start_serving=True, cleanup_socket=True)

Similar to loop.create_server() but works with the AF_UNIX socket family.

path 는 유닉스 도메인 소켓의 이름이며, sock 매개 변수가 제공되지 않으면 필수입니다. 추상 유닉스 소켓, str, bytes, Path 경로가 지원됩니다.

If cleanup_socket is true then the Unix socket will automatically be removed from the filesystem when the server is closed, unless the socket has been replaced after the server has been created.

이 메서드의 인자에 대한 정보는 loop.create_server() 메서드의 설명서를 참조하십시오.

Availability: Unix.

버전 3.7에서 변경: Added the ssl_handshake_timeout and start_serving parameters. The path parameter can now be a Path object.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

버전 3.13에서 변경: Added the cleanup_socket parameter.

coroutine loop.connect_accepted_socket(protocol_factory, sock, *, ssl=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

이미 받아들인 연결을 트랜스포트/프로토콜 쌍으로 래핑합니다.

이 메서드는 asyncio 밖에서 연결을 받아들이지만, 그 연결을 처리하는데 asyncio 를 사용하는 서버에서 사용됩니다.

매개 변수:

protocol_factory 는 반드시 프로토콜 구현을 반환하는 콜러블이어야 합니다.

sock 은 socket.accept 가 반환한 기존 소켓 객체입니다.

참고

The sock argument transfers ownership of the socket to the transport created. To close the socket, call the transport’s close() method.

ssl 을 SSLContext 로 설정하면, 들어오는 연결에 SSL을 사용합니다.

ssl_handshake_timeout 은 (SSL 연결의 경우) 연결을 중단하기 전에 SSL 핸드 셰이크가 완료될 때까지 대기하는 시간(초)입니다. None (기본값) 이면 60.0 초가 사용됩니다.

ssl_shutdown_timeout is the time in seconds to wait for the SSL shutdown to complete before aborting the connection. 30.0 seconds if None (default).

(transport, protocol) 쌍을 반환합니다.

Added in version 3.5.3.

버전 3.7에서 변경: Added the ssl_handshake_timeout parameter.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

파일 전송

coroutine loop.sendfile(transport, file, offset=0, count=None, *, fallback=True)

file 을 transport 로 보냅니다. 전송된 총 바이트 수를 반환합니다.

이 메서드는 가능한 경우 고성능 os.sendfile() 을 사용합니다.

file 는 바이너리 모드로 열린 일반 파일 객체여야 합니다.

offset 은 파일 읽기 시작할 위치를 알려줍니다. count 를 제공하면, EOF에 도달할 때까지 파일을 보내는 대신, 전송할 총 바이트 수를 지정합니다. 파일의 위치가 갱신됩니다, 이 메서드가 에러를 일으킬 때조차. 그리고, file.tell() 는 실제 전송된 바이트 수를 얻는 데 사용될 수 있습니다.

fallback 을 True 로 설정하면, 플랫폼이 sendfile 시스템 호출을 지원하지 않을 때 (가령 유닉스에서 SSL 소켓을 사용하거나 윈도우인 경우), asyncio 가 파일을 수동으로 읽고 보내도록 합니다.

시스템이 sendfile 시스템 호출을 지원하지 않고 fallback 이 False 면 SendfileNotAvailableError 를 발생시킵니다.

Added in version 3.7.

TLS 업그레이드

coroutine loop.start_tls(transport, protocol, sslcontext, *, server_side=False, server_hostname=None, ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

기존 트랜스포트 기반 연결을 TLS로 업그레이드합니다.

Create a TLS coder/decoder instance and insert it between the transport and the protocol. The coder/decoder implements both transport-facing protocol and protocol-facing transport.

Return the created two-interface instance. After await, the protocol must stop using the original transport and communicate with the returned object only because the coder caches protocol-side data and sporadically exchanges extra TLS session packets with transport.

In some situations (e.g. when the passed transport is already closing) this may return None.

매개 변수:

create_server()와 create_connection() 같은 메서드가 반환하는 transport 와 protocol 인스턴스.

sslcontext: 구성된 SSLContext 의 인스턴스.

(create_server() 에 의해 생성된 것과 같은) 서버 측 연결이 업그레이드될 때 server_side 에 True 를 전달합니다.

server_hostname: 대상 서버의 인증서가 일치될 호스트 이름을 설정하거나 대체합니다.

ssl_handshake_timeout 은 (TLS 연결의 경우) 연결을 중단하기 전에 TLS 핸드 셰이크가 완료될 때까지 대기하는 시간(초)입니다. None (기본값) 이면 60.0 초가 사용됩니다.

ssl_shutdown_timeout is the time in seconds to wait for the SSL shutdown to complete before aborting the connection. 30.0 seconds if None (default).

Added in version 3.7.

버전 3.11에서 변경: Added the ssl_shutdown_timeout parameter.

파일 기술자 관찰하기

loop.add_reader(fd, callback, *args)

fd 파일 기술자가 읽기 가능한지 관찰하기 시작하고, 일단 fd가 읽기 가능해지면 지정한 인자로 callback 을 호출합니다.

loop.remove_reader(fd)

Stop monitoring the fd file descriptor for read availability. Returns True if fd was previously being monitored for reads.

loop.add_writer(fd, callback, *args)

fd 파일 기술자가 쓰기 가능한지 관찰하기 시작하고, 일단 fd가 쓰기 가능해지면 지정한 인자로 callback 을 호출합니다.

callback 에 키워드 인자를 전달하려면 functools.partial()를 사용하십시오.

loop.remove_writer(fd)

Stop monitoring the fd file descriptor for write availability. Returns True if fd was previously being monitored for writes.

이 메서드의 일부 제한 사항은 플랫폼 지원 절을 참조하십시오.

소켓 객체로 직접 작업하기

일반적으로 loop.create_connection() 및 loop.create_server()와 같은 트랜스포트 기반 API를 사용하는 프로토콜 구현은 소켓을 직접 사용하는 구현보다 빠릅니다. 그러나, 성능이 결정적이지 않고 socket 객체로 직접 작업하는 것이 더 편리한 사용 사례가 있습니다.

coroutine loop.sock_recv(sock, nbytes)

sock 에서 최대 nbytes 를 수신합니다. socket.recv() 의 비동기 버전.

수신한 데이터를 바이트열 객체로 반환합니다.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

버전 3.7에서 변경: 이 메서드가 항상 코루틴 메서드라고 설명되어왔지만, 파이썬 3.7 이전에는 Future를 반환했습니다. 파이썬 3.7부터, 이것은 async def 메서드입니다.

coroutine loop.sock_recv_into(sock, buf)

sock 에서 buf 버퍼로 데이터를 수신합니다. 블로킹 socket.recv_into() 메서드를 따라 만들어졌습니다.

버퍼에 기록된 바이트 수를 돌려줍니다.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

Added in version 3.7.

coroutine loop.sock_recvfrom(sock, bufsize)

Receive a datagram of up to bufsize from sock. Asynchronous version of socket.recvfrom().

Return a tuple of (received data, remote address).

sock 은 반드시 비 블로킹 소켓이어야 합니다.

Added in version 3.11.

coroutine loop.sock_recvfrom_into(sock, buf, nbytes=0)

Receive a datagram of up to nbytes from sock into buf. Asynchronous version of socket.recvfrom_into().

Return a tuple of (number of bytes received, remote address).

sock 은 반드시 비 블로킹 소켓이어야 합니다.

Added in version 3.11.

coroutine loop.sock_sendall(sock, data)

data 를 sock 소켓으로 보냅니다. socket.sendall() 의 비동기 버전.

이 메서드는 data 의 모든 데이터가 송신되거나 에러가 발생할 때까지 소켓으로 계속 송신합니다. 성공하면 None 이 반환됩니다. 에러가 발생하면 예외가 발생합니다. 또한, 연결의 수신 단에서 성공적으로 처리한 (있기는 하다면) 데이터의 크기를 확인하는 방법은 없습니다.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

버전 3.7에서 변경: 이 메서드가 항상 코루틴 메서드라고 설명되어왔지만, 파이썬 3.7 이전에는 Future를 반환했습니다. 파이썬 3.7부터, 이것은 async def 메서드입니다.

coroutine loop.sock_sendto(sock, data, address)

Send a datagram from sock to address. Asynchronous version of socket.sendto().

Return the number of bytes sent.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

Added in version 3.11.

coroutine loop.sock_connect(sock, address)

sock을 address에 있는 원격 소켓에 연결합니다.

socket.connect() 의 비동기 버전.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

버전 3.5.2에서 변경: address 는 더는 결정될 필요가 없습니다. sock_connect 는 socket.inet_pton()을 호출하여 address 가 이미 결정되었는지를 검사합니다. 그렇지 않으면, loop.getaddrinfo() 가 address 를 결정하는 데 사용됩니다.

더 보기

loop.create_connection()과 asyncio.open_connection().

coroutine loop.sock_accept(sock)

연결을 받아들입니다. 블로킹 socket.accept() 메서드를 따라 만들어졌습니다.

소켓은 주소에 바인드 되어 연결을 리스닝해야 합니다. 반환 값은 (conn, address) 쌍인데, conn 은 연결로 데이터를 주고받을 수 있는 새 소켓 객체이고, address 는 연결의 반대편 끝의 소켓에 바인드 된 주소입니다.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

버전 3.7에서 변경: 이 메서드가 항상 코루틴 메서드라고 설명되어왔지만, 파이썬 3.7 이전에는 Future를 반환했습니다. 파이썬 3.7부터, 이것은 async def 메서드입니다.

더 보기

loop.create_server()와 start_server().

coroutine loop.sock_sendfile(sock, file, offset=0, count=None, *, fallback=True)

가능하면 고성능 os.sendfile 을 사용하여 파일을 보냅니다. 전송된 총 바이트 수를 반환합니다.

socket.sendfile()의 비동기 버전.

sock 은 반드시 비 블로킹 socket.SOCK_STREAM socket 이어야 합니다.

file 는 바이너리 모드로 열린 일반 파일 객체여야 합니다.

offset 은 파일 읽기 시작할 위치를 알려줍니다. count 를 제공하면, EOF에 도달할 때까지 파일을 보내는 대신, 전송할 총 바이트 수를 지정합니다. 파일의 위치가 갱신됩니다, 이 메서드가 에러를 일으킬 때조차. 그리고, file.tell() 는 실제 전송된 바이트 수를 얻는 데 사용될 수 있습니다.

fallback 을 True 로 설정하면, 플랫폼이 sendfile 시스템 호출을 지원하지 않을 때 (가령 유닉스에서 SSL 소켓을 사용하거나 윈도우인 경우), asyncio 가 파일을 수동으로 읽고 보내도록 합니다.

시스템이 sendfile 시스템 호출을 지원하지 않고 fallback 이 False 면 SendfileNotAvailableError 를 발생시킵니다.

sock 은 반드시 비 블로킹 소켓이어야 합니다.

Added in version 3.7.

DNS

coroutine loop.getaddrinfo(host, port, *, family=0, type=0, proto=0, flags=0)

socket.getaddrinfo() 의 비동기 버전.

coroutine loop.getnameinfo(sockaddr, flags=0)

socket.getnameinfo() 의 비동기 버전.

참고

Both getaddrinfo and getnameinfo internally utilize their synchronous versions through the loop’s default thread pool executor. When this executor is saturated, these methods may experience delays, which higher-level networking libraries may report as increased timeouts. To mitigate this, consider using a custom executor for other user tasks, or setting a default executor with a larger number of workers.

버전 3.7에서 변경: getaddrinfo 와 getnameinfo 메서드는 모두 코루틴 메서드라고 설명되어왔지만, 파이썬 3.7 이전에 실제로는 asyncio.Future 객체를 반환했습니다. 파이썬 3.7부터 두 가지 메서드 모두 코루틴입니다.

파이프로 작업하기

coroutine loop.connect_read_pipe(protocol_factory, pipe)

이벤트 루프에 pipe의 읽기용 끝을 등록합니다.

protocol_factory 는 반드시 asyncio 프로토콜 구현을 반환하는 콜러블이어야 합니다.

pipe는 파일류 객체입니다.

쌍 (transport, protocol)를 반환합니다. 여기서 transport는 ReadTransport 인터페이스를 지원하고, protocol은 protocol_factory에 의해 인스턴스로 만들어진 객체입니다.

SelectorEventLoop 이벤트 루프를 사용하면, pipe 는 비 블로킹 모드로 설정됩니다.

coroutine loop.connect_write_pipe(protocol_factory, pipe)

이벤트 루프에 pipe의 쓰기용 끝을 등록합니다.

protocol_factory 는 반드시 asyncio 프로토콜 구현을 반환하는 콜러블이어야 합니다.

pipe는 파일류 객체입니다.

쌍 (transport, protocol)를 반환합니다. 여기서 transport는 WriteTransport 인터페이스를 지원하고, protocol은 protocol_factory에 의해 인스턴스로 만들어진 객체입니다.

SelectorEventLoop 이벤트 루프를 사용하면, pipe 는 비 블로킹 모드로 설정됩니다.

참고

윈도우에서 SelectorEventLoop는 위의 메서드들을 지원하지 않습니다. 윈도우에서는 대신 ProactorEventLoop를 사용하십시오.

더 보기

loop.subprocess_exec() 와 loop.subprocess_shell() 메서드.

유닉스 시그널

loop.add_signal_handler(signum, callback, *args)

callback을 signum 시그널의 처리기로 설정합니다.

콜백은 다른 대기 중인 콜백과 해당 이벤트 루프의 실행 가능한 코루틴과 함께 loop에 의해 호출됩니다. signal.signal()을 사용하여 등록된 시그널 처리기와 달리, 이 함수로 등록된 콜백은 이벤트 루프와 상호 작용할 수 있습니다.

시그널 번호가 유효하지 않거나 잡을 수 없으면 ValueError 를 발생시킵니다. 처리기를 설정하는 데 문제가 있는 경우 RuntimeError 를 발생시킵니다.

callback 에 키워드 인자를 전달하려면 functools.partial()를 사용하십시오.

signal.signal()와 마찬가지로, 이 함수는 메인 스레드에서 호출되어야 합니다.

loop.remove_signal_handler(sig)

sig 시그널의 처리기를 제거합니다.

시그널 처리기가 제거되면 True 를, 주어진 시그널에 처리기가 설정되지 않았으면 False 를 반환합니다.

Availability: Unix.

더 보기

signal 모듈.

스레드 또는 프로세스 풀에서 코드를 실행하기

awaitable loop.run_in_executor(executor, func, *args)

지정된 실행기에서 func 가 호출되도록 배치합니다.

The executor argument should be an concurrent.futures.Executor instance. The default executor is used if executor is None. The default executor can be set by loop.set_default_executor(), otherwise, a concurrent.futures.ThreadPoolExecutor will be lazy-initialized and used by run_in_executor() if needed.

예:

import asyncio
import concurrent.futures

def blocking_io():
    # File operations (such as logging) can block the
    # event loop: run them in a thread pool.
    with open('/dev/urandom', 'rb') as f:
        return f.read(100)

def cpu_bound():
    # CPU-bound operations will block the event loop:
    # in general it is preferable to run them in a
    # process pool.
    return sum(i * i for i in range(10 ** 7))

async def main():
    loop = asyncio.get_running_loop()

    ## Options:

    # 1. Run in the default loop's executor:
    result = await loop.run_in_executor(
        None, blocking_io)
    print('default thread pool', result)

    # 2. Run in a custom thread pool:
    with concurrent.futures.ThreadPoolExecutor() as pool:
        result = await loop.run_in_executor(
            pool, blocking_io)
        print('custom thread pool', result)

    # 3. Run in a custom process pool:
    with concurrent.futures.ProcessPoolExecutor() as pool:
        result = await loop.run_in_executor(
            pool, cpu_bound)
        print('custom process pool', result)

    # 4. Run in a custom interpreter pool:
    with concurrent.futures.InterpreterPoolExecutor() as pool:
        result = await loop.run_in_executor(
            pool, cpu_bound)
        print('custom interpreter pool', result)

if __name__ == '__main__':
    asyncio.run(main())

Note that the entry point guard (if __name__ == '__main__') is required for option 3 due to the peculiarities of multiprocessing, which is used by ProcessPoolExecutor. See Safe importing of main module.

이 메서드는 asyncio.Future 객체를 반환합니다.

func 에 키워드 인자를 전달하려면 functools.partial()를 사용하십시오.

버전 3.5.3에서 변경: loop.run_in_executor() 는 더는 자신이 만드는 스레드 풀 실행기의 max_workers 를 설정하지 않습니다. 대신 스레드 풀 실행기(ThreadPoolExecutor)가 스스로 기본값을 설정하도록 합니다.

loop.set_default_executor(executor)

Set executor as the default executor used by run_in_executor(). executor must be an instance of ThreadPoolExecutor, which includes InterpreterPoolExecutor.

버전 3.11에서 변경: executor must be an instance of ThreadPoolExecutor.

에러 처리 API

이벤트 루프에서 예외를 처리하는 방법을 사용자 정의 할 수 있습니다.

loop.set_exception_handler(handler)

handler 를 새 이벤트 루프 예외 처리기로 설정합니다.

handler가 None 이면, 기본 예외 처리기가 설정됩니다. 그렇지 않으면, handler는 반드시 (loop, context) 와 일치하는 서명을 가진 콜러블이어야 합니다. 여기서 loop는 활성 이벤트 루프에 대한 참조가 될 것이고, context 는 예외에 관한 세부 정보를 담고 있는 dict 객체가 됩니다 (context에 대한 자세한 내용은 call_exception_handler() 문서를 참조하십시오).

If the handler is called on behalf of a Task or Handle, it is run in the contextvars.Context of that task or callback handle.

버전 3.12에서 변경: The handler may be called in the Context of the task or handle where the exception originated.

loop.get_exception_handler()

현재 예외 처리기를 반환하거나, 사용자 정의 예외 처리기가 설정되지 않았으면 None 을 반환합니다.

Added in version 3.5.2.

loop.default_exception_handler(context)

기본 예외 처리기.

예외가 발생하고 예외 처리기가 설정되지 않았을 때 호출됩니다. 기본 동작으로 위임하려는 사용자 정의 예외 처리기가 호출할 수 있습니다.

context 매개 변수는 call_exception_handler() 에서와 같은 의미입니다.

loop.call_exception_handler(context)

현재 이벤트 루프 예외 처리기를 호출합니다.

context 는 다음 키를 포함하는 dict 객체입니다 (새 키가 미래의 파이썬 버전에서 추가될 수 있습니다):

‘message’: 에러 메시지;

‘exception’ (선택적): 예외 객체;

‘future’ (선택적): asyncio.Future 인스턴스;

‘task’ (optional): asyncio.Task instance;

‘handle’ (선택적): asyncio.Handle 인스턴스;

‘protocol’ (선택적): 프로토콜 인스턴스;

‘transport’ (선택적): 트랜스포트 인스턴스;

‘socket’ (optional): socket.socket instance;

‘asyncgen’ (optional): Asynchronous generator that caused

the exception.

참고

This method should not be overloaded in subclassed event loops. For custom exception handling, use the set_exception_handler() method.

디버그 모드 활성화

loop.get_debug()

이벤트 루프의 디버그 모드(bool)를 가져옵니다.

기본값은 환경 변수 PYTHONASYNCIODEBUG 가 비어 있지 않은 문자열로 설정되면 True 이고, 그렇지 않으면 False 입니다.

loop.set_debug(enabled: bool)

이벤트 루프의 디버그 모드를 설정합니다.

버전 3.7에서 변경: 이제 새로운 파이썬 개발 모드를 사용하여 디버그 모드를 활성화할 수도 있습니다.

loop.slow_callback_duration

This attribute can be used to set the minimum execution duration in seconds that is considered “slow”. When debug mode is enabled, “slow” callbacks are logged.

Default value is 100 milliseconds.

더 보기

asyncio의 디버그 모드.

자식 프로세스 실행하기

이 하위 절에서 설명하는 메서드는 저수준입니다. 일반적인 async/await 코드에서는 대신 고수준의 asyncio.create_subprocess_shell() 및 asyncio.create_subprocess_exec() 편리 함수를 사용하는 것을 고려하십시오.

참고

On Windows, the default event loop ProactorEventLoop supports subprocesses, whereas SelectorEventLoop does not. See Subprocess Support on Windows for details.

coroutine loop.subprocess_exec(protocol_factory, *args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, **kwargs)

args로 지정된 하나 이상의 문자열 인자로 서브 프로세스를 만듭니다.

args는 반드시 다음과 같은 것으로 표현되는 문자열의 목록이어야 합니다:

str;

또는 파일 시스템 인코딩으로로 인코딩된 bytes.

첫 번째 문자열은 프로그램 실행 파일을 지정하고, 나머지 문자열은 인자를 지정합니다. 함께, 문자열 인자들은 프로그램의 argv를 구성합니다.

이것은 shell=False와 문자열의 목록을 첫 번째 인자로 호출된 표준 라이브러리 subprocess.Popen 클래스와 유사합니다. 그러나 Popen이 문자열 목록인 단일 인자를 받아들이지만, subprocess_exec는 여러 문자열 인자를 받아들입니다.

protocol_factory는 반드시 asyncio.SubprocessProtocol 클래스의 서브 클래스를 반환하는 콜러블이어야 합니다.

다른 매개 변수:

stdin은 다음 중 하나일 수 있습니다:

a file-like object

an existing file descriptor (a positive integer), for example those created with os.pipe()

subprocess.PIPE 상수 (기본값), 새 파이프를 만들고 연결합니다,

서브 프로세스가 이 프로세스의 파일 기술자를 상속하게 하는 값 None

특수 os.devnull 파일이 사용될 것임을 나타내는 subprocess.DEVNULL 상수

stdout은 다음 중 하나일 수 있습니다:

a file-like object

subprocess.PIPE 상수 (기본값), 새 파이프를 만들고 연결합니다,

서브 프로세스가 이 프로세스의 파일 기술자를 상속하게 하는 값 None

특수 os.devnull 파일이 사용될 것임을 나타내는 subprocess.DEVNULL 상수

stderr은 다음 중 하나일 수 있습니다:

a file-like object

subprocess.PIPE 상수 (기본값), 새 파이프를 만들고 연결합니다,

서브 프로세스가 이 프로세스의 파일 기술자를 상속하게 하는 값 None

특수 os.devnull 파일이 사용될 것임을 나타내는 subprocess.DEVNULL 상수

subprocess.STDOUT 상수, 표준 에러 스트림을 프로세스의 표준 출력 스트림에 연결합니다

다른 모든 키워드 인자는 해석 없이 subprocess.Popen로 전달됩니다. 다만, bufsize, universal_newlines, shell, text, encoding 및 errors는 예외인데, 이것들은 지정되지 않아야 합니다.

asyncio 서브 프로세스 API는 스트림을 텍스트로 디코딩하는 것을 지원하지 않습니다. bytes.decode()는 스트림에서 반환된 바이트열을 텍스트로 변환하는 데 사용될 수 있습니다.

If a file-like object passed as stdin, stdout or stderr represents a pipe, then the other side of this pipe should be registered with connect_write_pipe() or connect_read_pipe() for use with the event loop.

다른 인자에 관한 설명은 subprocess.Popen 클래스의 생성자를 참조하십시오.

(transport, protocol) 쌍을 반환합니다. 여기에서 transport는 asyncio.SubprocessTransport 베이스 클래스를 따르고, protocol은 protocol_factory에 의해 인스턴스로 만들어진 객체입니다.

coroutine loop.subprocess_shell(protocol_factory, cmd, *, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, **kwargs)

플랫폼의 “셸” 구문을 사용하는 cmd로 자식 프로세스를 만듭니다. cmd는 str이나 파일 시스템 인코딩으로 인코딩된 bytes 일 수 있습니다.

이것은 shell=True로 호출된 표준 라이브러리 subprocess.Popen 클래스와 유사합니다.

protocol_factory는 반드시 SubprocessProtocol 클래스의 서브 클래스를 반환하는 콜러블이어야 합니다.

나머지 인자에 관한 자세한 내용은 subprocess_exec()를 참조하십시오.

(transport, protocol) 쌍을 반환합니다. 여기서 transport는 SubprocessTransport 베이스 클래스를 따르고, protocol은 protocol_factory에 의해 인스턴스로 만들어진 객체입니다.

참고

셸 주입 [https://en.wikipedia.org/wiki/Shell_injection#Shell_injection] 취약점을 피하고자 모든 공백과 특수 문자를 적절하게 따옴표 처리하는 것은 응용 프로그램의 책임입니다. shlex.quote() 함수를 사용하여 셸 명령을 구성하는 데 사용될 문자열에 있는 공백 및 특수 문자를 올바르게 이스케이프 할 수 있습니다.

콜백 핸들

class asyncio.Handle

loop.call_soon(), loop.call_soon_threadsafe() 에 의해 반환되는 콜백 래퍼 객체.

get_context()

Return the contextvars.Context object associated with the handle.

Added in version 3.12.

cancel()

콜백을 취소합니다. 콜백이 이미 취소되었거나 실행되었다면 이 메서드는 아무 효과가 없습니다.

cancelled()

콜백이 취소되었으면 True 을 반환합니다.

Added in version 3.7.

class asyncio.TimerHandle

loop.call_later() 및 loop.call_at() 에 의해 반환되는 콜백 래퍼 객체.

이 클래스는 Handle의 서브 클래스입니다.

when()

예약된 콜백 시간을 float 초로 반환합니다.

시간은 절대 타임스탬프입니다. loop.time() 과 같은 시간 참조를 사용합니다.

Added in version 3.7.

서버 객체

Server 객체는 loop.create_server(), loop.create_unix_server(), start_server(), start_unix_server()로 만듭니다.

Do not instantiate the Server class directly.

class asyncio.Server

Server 객체는 비동기 컨텍스트 관리자입니다. async with 문에서 사용될 때, async with 문이 완료되면 서버 객체가 닫혀 있고 새 연결을 받아들이지 않는다는 것이 보장됩니다:

srv = await loop.create_server(...)

async with srv:
    # some code

# At this point, srv is closed and no longer accepts new connections.

버전 3.7에서 변경: Server 객체는 파이썬 3.7부터 비동기 컨텍스트 관리자입니다.

버전 3.11에서 변경: This class was exposed publicly as asyncio.Server in Python 3.9.11, 3.10.3 and 3.11.

close()

서버를 중지합니다: 리스닝 소켓을 닫고 sockets 어트리뷰트를 None 으로 설정합니다.

이미 받아들여진 클라이언트 연결을 나타내는 소켓은 열린 채로 있습니다.

The server is closed asynchronously; use the wait_closed() coroutine to wait until the server is closed (and no more connections are active).

close_clients()

Close all existing incoming client connections.

Calls close() on all associated transports.

close() should be called before close_clients() when closing the server to avoid races with new clients connecting.

Added in version 3.13.

abort_clients()

Close all existing incoming client connections immediately, without waiting for pending operations to complete.

Calls abort() on all associated transports.

close() should be called before abort_clients() when closing the server to avoid races with new clients connecting.

Added in version 3.13.

get_loop()

서버 객체와 연관된 이벤트 루프를 반환합니다.

Added in version 3.7.

coroutine start_serving()

연결을 받아들이기 시작합니다.

This method is idempotent, so it can be called when the server is already serving.

loop.create_server()와 asyncio.start_server() 의 start_serving 키워드 전용 매개 변수는 즉시 연결을 받아들이지 않는 서버 객체를 만들 수 있도록 합니다. 이 경우 Server.start_serving(), 또는 Server.serve_forever()를 사용하여 Server가 연결을 받아들이기 시작하도록 할 수 있습니다.

Added in version 3.7.

coroutine serve_forever()

코루틴이 취소될 때까지 연결을 받아들이기 시작합니다. serve_forever 태스크를 취소하면 서버가 닫힙니다.

이 메서드는 서버가 이미 연결을 받아들이고 있어도 호출 할 수 있습니다. 하나의 Server 객체 당 하나의 serve_forever 태스크만 존재할 수 있습니다.

예:

async def client_connected(reader, writer):
    # Communicate with the client with
    # reader/writer streams.  For example:
    await reader.readline()

async def main(host, port):
    srv = await asyncio.start_server(
        client_connected, host, port)
    await srv.serve_forever()

asyncio.run(main('127.0.0.1', 0))

Added in version 3.7.

is_serving()

서버가 새 연결을 받아들이고 있으면 True 를 반환합니다.

Added in version 3.7.

coroutine wait_closed()

Wait until the close() method completes and all active connections have finished.

sockets

List of socket-like objects, asyncio.trsock.TransportSocket, which the server is listening on.

버전 3.7에서 변경: 파이썬 3.7 이전에는 Server.sockets 가 서버 소켓의 내부 리스트를 직접 반환했습니다. 3.7에서는 그 리스트의 복사본이 반환됩니다.

이벤트 루프 구현

asyncio에는 두 가지 이벤트 루프 구현이 함께 제공됩니다: SelectorEventLoop 및 ProactorEventLoop.

By default asyncio is configured to use EventLoop.

class asyncio.SelectorEventLoop

A subclass of AbstractEventLoop based on the selectors module.

주어진 플랫폼에서 사용할 수 있는 가장 효율적인 selector를 사용합니다. 정확한 셀렉터 구현을 수동으로 구성하여 사용할 수도 있습니다.:

import asyncio
import selectors

class MyPolicy(asyncio.DefaultEventLoopPolicy):
   def new_event_loop(self):
      selector = selectors.SelectSelector()
      return asyncio.SelectorEventLoop(selector)

asyncio.set_event_loop_policy(MyPolicy())

Availability: Unix, Windows.

class asyncio.ProactorEventLoop

A subclass of AbstractEventLoop for Windows that uses “I/O Completion Ports” (IOCP).

Availability: Windows.

더 보기

MSDN documentation on I/O Completion Ports [https://learn.microsoft.com/windows/win32/fileio/i-o-completion-ports].

class asyncio.EventLoop

An alias to the most efficient available subclass of AbstractEventLoop for the given platform.

It is an alias to SelectorEventLoop on Unix and ProactorEventLoop on Windows.

Added in version 3.13.

class asyncio.AbstractEventLoop

asyncio 호환 이벤트 루프의 추상 베이스 클래스.

The 이벤트 루프 메서드 section lists all methods that an alternative implementation of AbstractEventLoop should have defined.

예제

이 절의 모든 예는 의도적으로 loop.run_forever() 및 loop.call_soon()와 같은 저수준 이벤트 루프 API를 사용하는 방법을 보여줍니다. 현대 asyncio 응용 프로그램은 거의 이런 식으로 작성할 필요가 없습니다; asyncio.run()과 같은 고수준 함수를 사용하는 것을 고려하십시오.

call_soon()을 사용하는 Hello World

콜백을 예약하기 위해 loop.call_soon() 메서드를 사용하는 예제. 콜백은 "Hello World" 를 표시한 다음 이벤트 루프를 중지합니다:

import asyncio

def hello_world(loop):
    """A callback to print 'Hello World' and stop the event loop"""
    print('Hello World')
    loop.stop()

loop = asyncio.new_event_loop()

# Schedule a call to hello_world()
loop.call_soon(hello_world, loop)

# Blocking call interrupted by loop.stop()
try:
    loop.run_forever()
finally:
    loop.close()

더 보기

코루틴과 run() 함수로 작성된 유사한 Hello World 예제.

call_later()로 현재 날짜를 표시합니다.

초마다 현재 날짜를 표시하는 콜백의 예입니다. 콜백은 loop.call_later() 메서드를 사용하여 5초 동안 자신을 다시 예약한 다음 이벤트 루프를 중지합니다:

import asyncio
import datetime

def display_date(end_time, loop):
    print(datetime.datetime.now())
    if (loop.time() + 1.0) < end_time:
        loop.call_later(1, display_date, end_time, loop)
    else:
        loop.stop()

loop = asyncio.new_event_loop()

# Schedule the first call to display_date()
end_time = loop.time() + 5.0
loop.call_soon(display_date, end_time, loop)

# Blocking call interrupted by loop.stop()
try:
    loop.run_forever()
finally:
    loop.close()

더 보기

코루틴과 run() 함수로 작성된 유사한 현재 날짜 예제.

파일 기술자에서 읽기 이벤트를 관찰하기

loop.add_reader() 메서드를 사용하여 파일 기술자가 데이터를 수신할 때까지 기다렸다가 이벤트 루프를 닫습니다:

import asyncio
from socket import socketpair

# Create a pair of connected file descriptors
rsock, wsock = socketpair()

loop = asyncio.new_event_loop()

def reader():
    data = rsock.recv(100)
    print("Received:", data.decode())

    # We are done: unregister the file descriptor
    loop.remove_reader(rsock)

    # Stop the event loop
    loop.stop()

# Register the file descriptor for read event
loop.add_reader(rsock, reader)

# Simulate the reception of data from the network
loop.call_soon(wsock.send, 'abc'.encode())

try:
    # Run the event loop
    loop.run_forever()
finally:
    # We are done. Close sockets and the event loop.
    rsock.close()
    wsock.close()
    loop.close()

더 보기

트랜스포트, 프로토콜, loop.create_connection() 메서드를 사용한 유사한 예제.

고수준의 asyncio.open_connection() 함수와 스트림을 사용하는 또 다른 유사한 예제.

SIGINT 및 SIGTERM에 대한 시그널 처리기 설정

(이 signals 예제는 유닉스에서만 작동합니다.)

Register handlers for signals SIGINT and SIGTERM using the loop.add_signal_handler() method:

import asyncio
import functools
import os
import signal

def ask_exit(signame, loop):
    print("got signal %s: exit" % signame)
    loop.stop()

async def main():
    loop = asyncio.get_running_loop()

    for signame in {'SIGINT', 'SIGTERM'}:
        loop.add_signal_handler(
            getattr(signal, signame),
            functools.partial(ask_exit, signame, loop))

    await asyncio.sleep(3600)

print("Event loop running for 1 hour, press Ctrl+C to interrupt.")
print(f"pid {os.getpid()}: send SIGINT or SIGTERM to exit.")

asyncio.run(main())

퓨처

소스 코드: Lib/asyncio/futures.py [https://github.com/python/cpython/tree/main/Lib/asyncio/futures.py], Lib/asyncio/base_futures.py [https://github.com/python/cpython/tree/main/Lib/asyncio/base_futures.py]

Future 객체는 저수준 콜백 기반 코드와 고수준 async/await 코드 간에 다리를 놓는 데 사용됩니다.

퓨처 함수

asyncio.isfuture(obj)

obj가 다음 중 하나면 True를 반환합니다:

asyncio.Future의 인스턴스,

asyncio.Task의 인스턴스,

_asyncio_future_blocking 어트리뷰트를 가진 퓨처류 객체.

Added in version 3.5.

asyncio.ensure_future(obj, *, loop=None)

다음을 반환합니다:

obj가 Future, Task 또는 퓨처류 객체면, obj 인자를 있는 그대로 (isfuture()로 검사합니다.)

obj가 코루틴이면, obj를 감싸는 Task 객체 (iscoroutine()로 검사합니다); 이 경우 코루틴은 ensure_future()로 예약됩니다.

obj가 어웨이터블이면, obj를 기다릴 Task 객체 (inspect.isawaitable()로 검사합니다.)

obj가 이 중 어느 것도 아니면, TypeError가 발생합니다.

중요

새 태스크를 만드는 데 선호되는 create_task() 함수도 참조하십시오.

Save a reference to the result of this function, to avoid a task disappearing mid-execution.

버전 3.5.1에서 변경: 함수는 모든 어웨이터블 객체를 받아들입니다.

버전 3.10부터 폐지됨: Deprecation warning is emitted if obj is not a Future-like object and loop is not specified and there is no running event loop.

asyncio.wrap_future(future, *, loop=None)

concurrent.futures.Future 객체를 asyncio.Future 객체로 감쌉니다.

버전 3.10부터 폐지됨: Deprecation warning is emitted if future is not a Future-like object and loop is not specified and there is no running event loop.

Future 객체

class asyncio.Future(*, loop=None)

Future는 비동기 연산의 최종 결과를 나타냅니다. 스레드 안전하지 않습니다.

Future is an awaitable object. Coroutines can await on Future objects until they either have a result or an exception set, or until they are cancelled. A Future can be awaited multiple times and the result is same.

일반적으로 퓨처는 저수준 콜백 기반 코드(예를 들어, asyncio 트랜스포트를 사용하여 구현된 프로토콜에서)가 고수준 async/await 코드와 상호 운용되도록 하는 데 사용됩니다.

간단한 규칙은 사용자가 만나는 API에서 Future 객체를 절대 노출하지 않는 것이며, Future 객체를 만드는 권장 방법은 loop.create_future()를 호출하는 것입니다. 이런 식으로 대체 이벤트 루프 구현이 자신의 최적화된 Future 객체 구현을 주입할 수 있습니다.

버전 3.7에서 변경: contextvars 모듈에 대한 지원이 추가되었습니다.

버전 3.10부터 폐지됨: Deprecation warning is emitted if loop is not specified and there is no running event loop.

result()

Future의 결과를 반환합니다.

Future가 완료(done)했고 set_result() 메서드로 결과가 설정되었으면, 결괏값이 반환됩니다.

Future가 완료(done)했고 set_exception() 메서드로 예외가 설정되었으면, 이 메서드는 예외를 발생시킵니다.

Future가 취소(cancelled)되었으면, 이 메서드는 CancelledError 예외를 발생시킵니다.

If the Future’s result isn’t yet available, this method raises an InvalidStateError exception.

set_result(result)

Future를 완료(done)로 표시하고, 그 결과를 설정합니다.

Raises an InvalidStateError error if the Future is already done.

set_exception(exception)

Future를 완료(done)로 표시하고, 예외를 설정합니다.

Raises an InvalidStateError error if the Future is already done.

done()

Future가 완료(done)했으면 True를 반환합니다.

Future는 취소(cancelled)되었거나 set_result() 나 set_exception() 호출로 결과나 예외가 설정되면 완료(done)됩니다.

cancelled()

Future가 최소(cancelled)되었으면, True를 반환합니다.

이 메서드는 대개 결과나 예외를 설정하기 전에 Future가 취소(cancelled)되었는지 확인하는 데 사용됩니다:

if not fut.cancelled():
    fut.set_result(42)

add_done_callback(callback, *, context=None)

Future가 완료(done)될 때 실행할 콜백을 추가합니다.

callback는 유일한 인자인 Future 객체로 호출됩니다.

이 메서드가 호출될 때 Future가 이미 완료(done)되었으면, 콜백이 loop.call_soon()으로 예약됩니다.

선택적 키워드 전용 context 인자는 callback이 실행될 사용자 정의 contextvars.Context를 지정할 수 있도록 합니다. context가 제공되지 않으면 현재 컨텍스트가 사용됩니다.

functools.partial()을 사용하여 매개 변수를 callback에 전달할 수 있습니다, 예를 들어:

# Call 'print("Future:", fut)' when "fut" is done.
fut.add_done_callback(
    functools.partial(print, "Future:"))

버전 3.7에서 변경: context 키워드 전용 매개 변수가 추가되었습니다. 자세한 내용은 PEP 567 [https://peps.python.org/pep-0567/]을 참조하십시오.

remove_done_callback(callback)

콜백 목록에서 callback을 제거합니다.

제거된 콜백 수를 반환합니다. 콜백이 두 번 이상 추가되지 않는 한 일반적으로 1입니다.

cancel(msg=None)

Future를 취소하고 콜백을 예약합니다.

Future가 이미 완료(done)했거나 취소(cancelled)되었으면, False를 반환합니다. 그렇지 않으면 Future의 상태를 취소(cancelled)로 변경하고, 콜백을 예약한 다음 True를 반환합니다.

버전 3.9에서 변경: Added the msg parameter.

exception()

이 Future에 설정된 예외를 반환합니다.

Future가 완료(done)했을 때만 예외(또는 예외가 설정되지 않았으면 None)가 반환됩니다.

Future가 취소(cancelled)되었으면, 이 메서드는 CancelledError 예외를 발생시킵니다.

Future가 아직 완료(done)하지 않았으면, 이 메서드는 InvalidStateError 예외를 발생시킵니다.

get_loop()

Future 객체가 연결된 이벤트 루프를 반환합니다.

Added in version 3.7.

이 예제는 Future 객체를 만들고, Future에 결과를 설정하는 비동기 Task를 만들고 예약하며, Future가 결과를 얻을 때까지 기다립니다:

async def set_after(fut, delay, value):
    # Sleep for *delay* seconds.
    await asyncio.sleep(delay)

    # Set *value* as a result of *fut* Future.
    fut.set_result(value)

async def main():
    # Get the current event loop.
    loop = asyncio.get_running_loop()

    # Create a new Future object.
    fut = loop.create_future()

    # Run "set_after()" coroutine in a parallel Task.
    # We are using the low-level "loop.create_task()" API here because
    # we already have a reference to the event loop at hand.
    # Otherwise we could have just used "asyncio.create_task()".
    loop.create_task(
        set_after(fut, 1, '... world'))

    print('hello ...')

    # Wait until *fut* has a result (1 second) and print it.
    print(await fut)

asyncio.run(main())

중요

Future 객체는 concurrent.futures.Future를 흉내 내도록 설계되었습니다. 주요 차이점은 다음과 같습니다:

asyncio 퓨처와는 달리, concurrent.futures.Future 인스턴스는 await 할 수 없습니다.

asyncio.Future.result() 와 asyncio.Future.exception()은 timeout 인자를 받아들이지 않습니다.

asyncio.Future.result() 와 asyncio.Future.exception()는 Future가 완료(done)하지 않았을 때 InvalidStateError 예외를 발생시킵니다.

asyncio.Future.add_done_callback()으로 등록된 콜백은 즉시 호출되지 않습니다. 대신 loop.call_soon()로 예약됩니다.

asyncio Future는 concurrent.futures.wait() 와 concurrent.futures.as_completed() 함수와 호환되지 않습니다.

asyncio.Future.cancel() accepts an optional msg argument, but concurrent.futures.Future.cancel() does not.

트랜스포트와 프로토콜

머리말

트랜스포트와 프로토콜은 loop.create_connection()와 같은 저수준 이벤트 루프 API에서 사용됩니다. 그들은 콜백 기반 프로그래밍 스타일을 사용하고 네트워크 나 IPC 프로토콜(예를 들어 HTTP)의 고성능 구현을 가능하게 합니다.

본질에서 트랜스포트와 프로토콜은 라이브러리와 프레임워크에서만 사용되어야 하며 고수준 asyncio 응용 프로그램에서는 사용되지 않아야 합니다.

이 문서 페이지는 트랜스포트와 프로토콜을 모두 다룹니다.

소개

최상위 수준에서, 트랜스포트는 어떻게(how) 바이트를 전송할지를 다루지만, 프로토콜은 어떤(which) 바이트를 전송할지를 결정합니다 (그리고 어느 정도는 언제(when)도).

같은 것을 다른 식으로 말하면: 트랜스포트는 소켓(또는 유사한 I/O 엔드포인트)의 추상화지만, 프로토콜은 트랜스포트의 관점에서 응용 프로그램의 추상화입니다.

또 다른 시각은 트랜스포트와 프로토콜 인터페이스가 함께 네트워크 I/O와 프로세스 간 I/O를 사용하기 위한 추상 인터페이스를 정의한다는 것입니다.

트랜스포트 객체와 프로토콜 객체 간에는 항상 1:1 관계가 있습니다: 프로토콜은 트랜스포트 메서드를 호출하여 데이터를 보내지만, 트랜스포트는 프로토콜 메서드를 호출하여 받은 데이터를 전달합니다.

대부분의 연결 지향 이벤트 루프 메서드(가령 loop.create_connection())는 Transport 객체로 표현되는 받아들인 연결을 위한 Protocol 객체를 만드는 데 사용되는 protocol_factory 인자를 받아들입니다. 이러한 메서드는 대개 (transport, protocol)의 튜플을 반환합니다.

목차

이 설명서 페이지는 다음 절로 구성됩니다:

트랜스포트 절은 asyncio BaseTransport, ReadTransport, WriteTransport, Transport, DatagramTransport 및 SubprocessTransport 클래스를 설명합니다.

프로토콜 절은 asyncio BaseProtocol, Protocol, BufferedProtocol, DatagramProtocol 및 SubprocessProtocol 클래스를 설명합니다.

예제 절은 트랜스포트, 프로토콜 및 저수준 이벤트 루프 API를 사용하는 방법을 보여줍니다.

트랜스포트

소스 코드: Lib/asyncio/transports.py [https://github.com/python/cpython/tree/main/Lib/asyncio/transports.py]

트랜스포트는 다양한 종류의 통신 채널을 추상화하기 위해 asyncio에서 제공하는 클래스입니다.

트랜스포트 객체는 항상 asyncio 이벤트 루프에 의해 인스턴스로 만들어집니다.

asyncio는 TCP, UDP, SSL 및 서브 프로세스 파이프를 위한 트랜스포트를 구현합니다. 트랜스포트에서 사용할 수 있는 메서드는 트랜스포트의 종류에 따라 다릅니다.

트랜스포트 클래스는 스레드 안전하지 않습니다.

트랜스포트 계층 구조

class asyncio.BaseTransport

모든 트랜스포트의 베이스 클래스. 모든 asyncio 트랜스포트가 공유하는 메서드를 포함합니다.

class asyncio.WriteTransport(BaseTransport)

쓰기 전용 연결을 위한 베이스 트랜스포트

WriteTransport 클래스의 인스턴스는 loop.connect_write_pipe() 이벤트 루프 메서드에서 반환되며 loop.subprocess_exec()와 같은 서브 프로세스 관련 메서드에서도 사용됩니다.

class asyncio.ReadTransport(BaseTransport)

읽기 전용 연결을 위한 베이스 트랜스포트

ReadTransport 클래스의 인스턴스는 loop.connect_read_pipe() 이벤트 루프 메서드에서 반환되며 loop.subprocess_exec()와 같은 서브 프로세스 관련 메서드에서도 사용됩니다.

class asyncio.Transport(WriteTransport, ReadTransport)

TCP 연결과 같은 양방향 트랜스포트를 나타내는 인터페이스.

사용자는 트랜스포트를 직접 인스턴스로 만들지 않습니다; 유틸리티 함수를 호출하고, 프로토콜 팩토리와 트랜스포트와 프로토콜을 만드는 데 필요한 기타 정보를 전달합니다.

Transport 클래스의 인스턴스는 loop.create_connection(), loop.create_unix_connection(), loop.create_server(), loop.sendfile() 등과 같은 이벤트 루프 메서드에서 반환되거나 사용됩니다.

class asyncio.DatagramTransport(BaseTransport)

데이터 그램 (UDP) 연결을 위한 트랜스포트.

DatagramTransport 클래스의 인스턴스는 loop.create_datagram_endpoint() 이벤트 루프 메서드에서 반환됩니다.

class asyncio.SubprocessTransport(BaseTransport)

부모와 그 자식 OS 프로세스 간의 연결을 나타내는 추상화.

SubprocessTransport 클래스의 인스턴스는 이벤트 루프 메서드 loop.subprocess_shell()과 loop.subprocess_exec()에서 반환됩니다.

베이스 트랜스포트

BaseTransport.close()

트랜스포트를 닫습니다.

If the transport has a buffer for outgoing data, buffered data will be flushed asynchronously. No more data will be received. After all buffered data is flushed, the protocol’s protocol.connection_lost() method will be called with None as its argument. The transport should not be used once it is closed.

BaseTransport.is_closing()

트랜스포트가 닫히는 중이거나 닫혔으면 True를 반환합니다.

BaseTransport.get_extra_info(name, default=None)

트랜스포트나 그것이 사용하는 하부 자원에 대한 정보를 반환합니다.

name은 얻고자 하는 트랜스포트 특정 정보의 조각을 나타내는 문자열입니다.

default는 정보가 없거나 트랜스포트가 제삼자 이벤트 루프 구현이나 현재 플랫폼에서 조회를 지원하지 않을 때 반환 할 값입니다.

예를 들어, 다음 코드는 트랜스포트의 하부 소켓 객체를 가져오려고 시도합니다:

sock = transport.get_extra_info('socket')
if sock is not None:
    print(sock.getsockopt(...))

일부 트랜스포트에서 조회할 수 있는 정보의 범주:

소켓:

'peername': 소켓이 연결된 원격 주소, socket.socket.getpeername()의 결과 (에러 시 None)

'socket': socket.socket 인스턴스

'sockname': 소켓 자체 주소, socket.socket.getsockname()의 결과

SSL 소켓:

'compression': 문자열로 표현된 사용된 압축 알고리즘, 또는 연결이 압축되지 않았으면 None; ssl.SSLSocket.compression()의 결과

'cipher': 사용되는 암호 체계의 이름, 이의 사용을 정의하는 SSL 프로토콜의 버전 및 사용되는 비밀 비트의 수를 포함하는 3-튜플; ssl.SSLSocket.cipher()의 결과

'peercert': 피어 인증서; ssl.SSLSocket.getpeercert()의 결과

'sslcontext': ssl.SSLContext 인스턴스

'ssl_object': ssl.SSLObject 나 ssl.SSLSocket 인스턴스

파이프:

'pipe': 파이프 객체

서브 프로세스:

'subprocess': subprocess.Popen 인스턴스

BaseTransport.set_protocol(protocol)

새 프로토콜을 설정합니다.

프로토콜의 교환은 두 프로토콜이 교환을 지원한다고 문서화 되었을 때만 수행되어야 합니다.

BaseTransport.get_protocol()

현재 프로토콜을 반환합니다.

읽기 전용 트랜스포트

ReadTransport.is_reading()

트랜스 포트가 새로운 데이터를 받고 있으면 True를 반환합니다.

Added in version 3.7.

ReadTransport.pause_reading()

트랜스포트의 수신 끝을 일시 중지합니다. resume_reading()이 호출 될 때까지 프로토콜의 protocol.data_received() 메서드에 데이터가 전달되지 않습니다.

버전 3.7에서 변경: 이 메서드는 멱등적(idempotent)입니다. 즉, 트랜스포트가 이미 일시 중지되거나 닫혔을 때도 호출할 수 있습니다.

ReadTransport.resume_reading()

수신 끝을 재개합니다. 읽을 수 있는 데이터가 있다면 프로토콜의 protocol.data_received() 메서드가 다시 한번 호출됩니다.

버전 3.7에서 변경: 이 메서드는 멱등적(idempotent)입니다. 즉, 트랜스포트가 이미 읽고 있을 때도 호출할 수 있습니다.

쓰기 전용 트랜스포트

WriteTransport.abort()

계류 중인 작업이 완료될 때까지 기다리지 않고, 즉시 트랜스포트를 닫습니다. 버퍼 된 데이터는 손실됩니다. 더는 데이터가 수신되지 않습니다. 프로토콜의 protocol.connection_lost() 메서드는 결국 None을 인자로 사용하여 호출됩니다.

WriteTransport.can_write_eof()

트랜스포트가 write_eof()를 지원하면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

WriteTransport.get_write_buffer_size()

트랜스포트가 사용하는 출력 버퍼의 현재 크기를 반환합니다.

WriteTransport.get_write_buffer_limits()

쓰기 흐름 제어를 위한 high 와 low 수위(watermark)를 가져옵니다. 튜플 (low, high)를 반환합니다. 여기서 low 와 high는 양의 바이트 수입니다.

제한을 설정하려면 set_write_buffer_limits()를 사용하십시오.

Added in version 3.4.2.

WriteTransport.set_write_buffer_limits(high=None, low=None)

쓰기 흐름 제어를 위한 high 와 low 수위(watermark)를 설정합니다.

이 두 값(바이트 수로 측정)은 프로토콜의 protocol.pause_writing() 과 protocol.resume_writing() 메서드가 언제 호출될지를 제어합니다. 지정하면, low 수위는 high 수위보다 작거나 같아야 합니다. high 와 low는 음수가 될 수 없습니다.

버퍼 크기가 high 값보다 크거나 같아질 때 pause_writing()가 호출됩니다. 쓰기가 일시 중지되면, 버퍼 크기가 low 값보다 작거나 같아질 때 resume_writing()이 호출됩니다.

기본값은 구현에 따라 다릅니다. high 수위만 주어지면, low 수위는 high 수위보다 작거나 같은 구현 특정 기본값이 사용됩니다. high를 0으로 설정하면, low도 0으로 설정되고, 버퍼가 비어있지 않게 될 때마다 pause_writing()가 호출되도록 합니다. low를 0으로 설정하면 버퍼가 빌 때만 resume_writing()이 호출됩니다. 두 제한 중 하나에 0을 사용하는 것은 I/O와 계산을 동시에 수행할 기회를 줄이기 때문에 일반적으로 최선이 아닙니다.

제한을 가져오려면 get_write_buffer_limits()를 사용하십시오.

WriteTransport.write(data)

어떤 data 바이트열을 트랜스포트에 기록합니다.

이 메서드는 블록하지 않습니다; 데이터를 버퍼하고 비동기적으로 전송되도록 배치합니다.

WriteTransport.writelines(list_of_data)

트랜스포트에 데이터 바이트열 리스트(또는 임의의 이터러블)를 기록합니다. 이것은 이터러블이 산출하는 각 요소에 대해 write()를 호출하는 것과 기능 면에서 동등하지만, 더 효율적으로 구현될 수 있습니다.

WriteTransport.write_eof()

버퍼 된 모든 데이터를 플러시 한 후 트랜스포트의 쓰기 끝을 닫습니다. 데이터가 여전히 수신될 수 있습니다.

이 메서드는 트랜스포트(예를 들어 SSL)가 반만 닫힌 연결을 지원하지 않으면 NotImplementedError를 발생시킬 수 있습니다.

데이터 그램 트랜스포트

DatagramTransport.sendto(data, addr=None)

addr(트랜스포트 종속적인 대상 주소)에 의해 주어진 원격 피어로 data 바이트열을 보냅니다. addr가 None이면, 트랜스포트를 만들 때 지정된 대상 주소로 data가 전송됩니다.

이 메서드는 블록하지 않습니다; 데이터를 버퍼하고 비동기적으로 전송되도록 배치합니다.

버전 3.13에서 변경: This method can be called with an empty bytes object to send a zero-length datagram. The buffer size calculation used for flow control is also updated to account for the datagram header.

DatagramTransport.abort()

계류 중인 작업이 완료될 때까지 기다리지 않고, 즉시 트랜스포트를 닫습니다. 버퍼 된 데이터는 손실됩니다. 더는 데이터가 수신되지 않습니다. 프로토콜의 protocol.connection_lost() 메서드는 결국 None을 인자로 사용하여 호출됩니다.

서브 프로세스 트랜스포트

SubprocessTransport.get_pid()

서브 프로세스 ID를 정수로 반환합니다.

SubprocessTransport.get_pipe_transport(fd)

정수 파일 기술자 fd에 대응하는 통신 파이프의 트랜스포트를 돌려줍니다:

0: 표준 입력(stdin)의 읽을 수 있는 스트리밍 트랜스포트, 또는 서브 프로세스가 stdin=PIPE로 만들어지지 않았으면 None

1: 표준 출력(stdout)의 쓸 수 있는 스트리밍 트랜스포트, 또는 서브 프로세스가 stdout=PIPE로 만들어지지 않았으면 None

2: 표준 오류(stderr)의 쓸 수 있는 스트리밍 트랜스포트, 또는 서브 프로세스가 stderr=PIPE로 만들어지지 않았으면 None

다른 fd: None

SubprocessTransport.get_returncode()

서브 프로세스 반환 값을 정수로, 혹은 반환되지 않았으면 None을 반환합니다. subprocess.Popen.returncode 어트리뷰트와 유사합니다.

SubprocessTransport.kill()

서브 프로세스를 죽입니다.

POSIX 시스템에서, 이 함수는 SIGKILL을 서브 프로세스로 보냅니다. 윈도우에서, 이 메서드는 terminate()의 별칭입니다.

subprocess.Popen.kill()도 참조하십시오.

SubprocessTransport.send_signal(signal)

subprocess.Popen.send_signal()와 마찬가지로 signal 번호를 서브 프로세스로 보냅니다.

SubprocessTransport.terminate()

서브 프로세스를 중지합니다.

On POSIX systems, this method sends SIGTERM to the subprocess. On Windows, the Windows API function TerminateProcess() is called to stop the subprocess.

subprocess.Popen.terminate()도 참조하십시오.

SubprocessTransport.close()

kill() 메서드를 호출하여 서브 프로세스를 죽입니다.

서브 프로세스가 아직 반환하지 않았으면, stdin, stdout 및 stderr 파이프의 트랜스포트를 닫습니다.

프로토콜

소스 코드: Lib/asyncio/protocols.py [https://github.com/python/cpython/tree/main/Lib/asyncio/protocols.py]

asyncio는 네트워크 프로토콜을 구현하는 데 사용해야 하는 추상 베이스 클래스 집합을 제공합니다. 이러한 클래스는 트랜스포트와 함께 사용해야 합니다.

추상 베이스 프로토콜 클래스의 서브 클래스는 일부 또는 모든 메서드를 구현할 수 있습니다. 이 모든 메서드는 콜백입니다: 이것들은 특정 이벤트에서 트랜스포트에 의해 호출됩니다, 예를 들어 어떤 데이터가 수신될 때. 베이스 프로토콜 메서드는 해당 트랜스포트에 의해 호출되어야 합니다.

베이스 프로토콜

class asyncio.BaseProtocol

모든 프로토콜이 공유하는 메서드를 가진 베이스 프로토콜.

class asyncio.Protocol(BaseProtocol)

스트리밍 프로토콜(TCP, 유닉스 소켓 등)을 구현하기 위한 베이스 클래스.

class asyncio.BufferedProtocol(BaseProtocol)

수신 버퍼의 수동 제어로 스트리밍 프로토콜을 구현하기 위한 베이스 클래스.

class asyncio.DatagramProtocol(BaseProtocol)

데이터 그램 (UDP) 프로토콜을 구현하기 위한 베이스 클래스.

class asyncio.SubprocessProtocol(BaseProtocol)

자식 프로세스와 통신하는 (단방향 파이프) 프로토콜을 구현하기 위한 베이스 클래스.

베이스 프로토콜

모든 asyncio 프로토콜은 베이스 프로토콜 콜백을 구현할 수 있습니다.

연결 콜백

연결 콜백은 모든 프로토콜에서 성공적으로 연결될 때마다 정확히 한 번 호출됩니다. 다른 모든 프로토콜 콜백은 이 두 메서드 사이에서만 호출될 수 있습니다.

BaseProtocol.connection_made(transport)

연결이 이루어질 때 호출됩니다.

transport 인자는 연결을 나타내는 트랜스포트입니다. 트랜스포트에 대한 참조를 저장하는 것은 프로토콜의 책임입니다.

BaseProtocol.connection_lost(exc)

연결이 끊어지거나 닫힐 때 호출됩니다.

인자는 예외 객체나 None입니다. 후자는 정상적인 EOF가 수신되었거나, 연결의 이쪽에서 연결이 중단(abort)되거나 닫혔다는 것을 의미합니다.

흐름 제어 콜백

흐름 제어 콜백은 프로토콜에 의해 수행되는 쓰기를 일시 중지하거나 다시 시작하도록 트랜스포트에 의해 호출될 수 있습니다.

자세한 내용은 set_write_buffer_limits() 메서드 설명서를 참조하십시오.

BaseProtocol.pause_writing()

트랜스포트 버퍼가 높은 수위를 넘을 때 호출됩니다.

BaseProtocol.resume_writing()

트랜스포트 버퍼가 낮은 수위 아래로 내려갈 때 호출됩니다.

버퍼 크기가 높은 수위와 같으면, pause_writing()이 호출되지 않습니다: 버퍼 크기는 엄격하게 초과해야 합니다.

반대로, resume_writing()은 버퍼 크기가 낮은 수위와 같거나 낮을 때 호출됩니다. 이러한 종료 조건은 수위가 0일 때 예상대로 진행되게 하려면 중요합니다.

스트리밍 프로토콜

loop.create_server(), loop.create_unix_server(), loop.create_connection(), loop.create_unix_connection(), loop.connect_accepted_socket(), loop.connect_read_pipe() 및 loop.connect_write_pipe()와 같은 이벤트 메서드는 스트리밍 프로토콜을 반환하는 팩토리를 받아들입니다.

Protocol.data_received(data)

어떤 데이터가 수신될 때 호출됩니다. data는 수신 데이터가 들어있는 비어 있지 않은 바이트열 객체입니다.

데이터가 버퍼 되고, 조각으로 나뉘고, 재조립되는지는 트랜스포트에 달려있습니다. 일반적으로, 특정 의미에 의존해서는 안 되며, 구문 분석을 일반적이고 유연하게 만들어야 합니다. 그러나, 데이터는 항상 올바른 순서로 수신됩니다.

이 메서드는 연결이 열려있는 동안 임의의 횟수만큼 호출될 수 있습니다.

However, protocol.eof_received() is called at most once. Once eof_received() is called, data_received() is not called anymore.

Protocol.eof_received()

다른 쪽 끝이 더는 데이터를 보내지 않을 것이라는 신호를 보낼 때 호출됩니다 (예를 들어, 다른 쪽 끝도 asyncio를 사용하면, transport.write_eof()를 호출하여).

이 메서드는 거짓 값(None 포함)을 반환할 수 있으며, 이때 트랜스포트는 스스로 닫힙니다. 반대로, 이 메서드가 참값을 반환하면, 사용된 프로토콜이 트랜스포트를 닫을지를 결정합니다. 기본 구현이 None을 반환하기 때문에, 묵시적으로 연결을 닫습니다.

SSL을 포함한 일부 트랜스포트는, 반만 닫힌 연결을 지원하지 않습니다. 이때, 이 메서드에서 참을 반환하면 연결이 닫힙니다.

상태 기계:

start -> connection_made
    [-> data_received]*
    [-> eof_received]?
-> connection_lost -> end

버퍼 된 스트리밍 프로토콜

Added in version 3.7.

버퍼 된 프로토콜은 스트리밍 프로토콜을 지원하는 모든 이벤트 루프 메서드와 함께 사용할 수 있습니다.

BufferedProtocol 구현은 수신 버퍼의 명시적 수동 할당과 제어를 허용합니다. 이벤트 루프는 프로토콜에서 제공하는 버퍼를 사용하여 불필요한 데이터 복사를 피할 수 있습니다. 이로 인해 대량의 데이터를 수신하는 프로토콜의 성능이 크게 향상될 수 있습니다. 정교한 프로토콜 구현은 버퍼 할당 수를 크게 줄일 수 있습니다.

다음 콜백은 BufferedProtocol 인스턴스에 호출됩니다.:

BufferedProtocol.get_buffer(sizehint)

새로운 수신 버퍼를 할당하기 위해서 호출됩니다.

sizehint는 반환되는 버퍼에 대해 권장되는 최소 크기입니다. sizehint가 제안하는 것보다 더 작거나 큰 버퍼를 반환하는 것이 허용됩니다. -1로 설정하면 버퍼 크기는 임의적일 수 있습니다. 크기가 0인 버퍼를 반환하는 것은 에러입니다.

get_buffer()는 버퍼 프로토콜을 구현하는 객체를 반환해야 합니다.

BufferedProtocol.buffer_updated(nbytes)

수신된 데이터로 버퍼가 갱신될 때 호출됩니다.

nbytes는 버퍼에 기록된 총 바이트 수입니다.

BufferedProtocol.eof_received()

protocol.eof_received() 메서드의 설명서를 참조하십시오.

get_buffer()는 연결 중에 임의의 횟수만큼 호출될 수 있습니다. 그러나, protocol.eof_received()는 최대한 한 번만 호출되며, 호출되면 get_buffer()와 buffer_updated()는 그 이후로 호출되지 않습니다.

상태 기계:

start -> connection_made
    [-> get_buffer
        [-> buffer_updated]?
    ]*
    [-> eof_received]?
-> connection_lost -> end

데이터 그램 프로토콜

데이터 그램 프로토콜 인스턴스는 loop.create_datagram_endpoint() 메서드에 전달된 프로토콜 팩토리에 의해 만들어져야 합니다.

DatagramProtocol.datagram_received(data, addr)

데이터 그램이 수신될 때 호출됩니다. data는 수신 데이터를 포함하는 바이트열 객체입니다. addr는 데이터를 보내는 피어의 주소입니다; 정확한 형식은 트랜스포트에 따라 다릅니다.

DatagramProtocol.error_received(exc)

이전의 송신이나 수신 연산이 OSError를 일으킬 때 호출됩니다. exc는 OSError 인스턴스입니다.

이 메서드는 드문 조건에서 호출됩니다, 트랜스포트(예를 들어 UDP)가 데이터 그램을 수신자에게 전달할 수 없음을 감지했을 때입니다. 하지만 대부분 전달할 수 없는 데이터 그램은 조용히 삭제됩니다.

참고

BSD 시스템(macOS, FreeBSD 등)에서는, 너무 많은 패킷을 쓰는 것으로 인한 전송 실패를 감지하는 신뢰성 있는 방법이 없으므로 데이터 그램 프로토콜에 대한 흐름 제어가 지원되지 않습니다.

소켓은 항상 ‘ready’로 나타나고 여분의 패킷은 삭제됩니다. errno가 errno.ENOBUFS로 설정된 OSError가 발생할 수도 그렇지 않을 수도 있습니다; 발생하면, DatagramProtocol.error_received()에게 보고되지만 그렇지 않으면 무시됩니다.

서브 프로세스 프로토콜

Subprocess Protocol instances should be constructed by protocol factories passed to the loop.subprocess_exec() and loop.subprocess_shell() methods.

SubprocessProtocol.pipe_data_received(fd, data)

자식 프로세스가 stdout 이나 stderr 파이프에 데이터를 쓸 때 호출됩니다.

fd는 파이프의 정수 파일 기술자입니다.

data는 수신 된 데이터를 포함하는 비어 있지 않은 바이트열 객체입니다.

SubprocessProtocol.pipe_connection_lost(fd, exc)

자식 프로세스와 통신하는 파이프 중 하나가 닫히면 호출됩니다.

fd는 닫힌 정수 파일 기술자입니다.

SubprocessProtocol.process_exited()

자식 프로세스가 종료할 때 호출됩니다.

It can be called before pipe_data_received() and pipe_connection_lost() methods.

예제

TCP 메아리 서버

loop.create_server() 메서드를 사용하여 TCP 메아리 서버를 만들고, 받은 데이터를 다시 보내고, 연결을 닫습니다:

import asyncio

class EchoServerProtocol(asyncio.Protocol):
    def connection_made(self, transport):
        peername = transport.get_extra_info('peername')
        print('Connection from {}'.format(peername))
        self.transport = transport

    def data_received(self, data):
        message = data.decode()
        print('Data received: {!r}'.format(message))

        print('Send: {!r}'.format(message))
        self.transport.write(data)

        print('Close the client socket')
        self.transport.close()

async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    server = await loop.create_server(
        EchoServerProtocol,
        '127.0.0.1', 8888)

    async with server:
        await server.serve_forever()

asyncio.run(main())

더 보기

스트림을 사용하는 TCP 메아리 서버 예제는 고수준 asyncio.start_server() 함수를 사용합니다.

TCP 메아리 클라이언트

loop.create_connection() 메서드를 사용하는 TCP 메아리 클라이언트, 데이터를 보내고 연결이 닫힐 때까지 기다립니다:

import asyncio

class EchoClientProtocol(asyncio.Protocol):
    def __init__(self, message, on_con_lost):
        self.message = message
        self.on_con_lost = on_con_lost

    def connection_made(self, transport):
        transport.write(self.message.encode())
        print('Data sent: {!r}'.format(self.message))

    def data_received(self, data):
        print('Data received: {!r}'.format(data.decode()))

    def connection_lost(self, exc):
        print('The server closed the connection')
        self.on_con_lost.set_result(True)

async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    on_con_lost = loop.create_future()
    message = 'Hello World!'

    transport, protocol = await loop.create_connection(
        lambda: EchoClientProtocol(message, on_con_lost),
        '127.0.0.1', 8888)

    # Wait until the protocol signals that the connection
    # is lost and close the transport.
    try:
        await on_con_lost
    finally:
        transport.close()

asyncio.run(main())

더 보기

스트림을 사용하는 TCP 메아리 클라이언트 예제는 고수준 asyncio.open_connection() 함수를 사용합니다.

UDP 메아리 서버

loop.create_datagram_endpoint() 메서드를 사용하는 UDP 메아리 서버, 수신된 데이터를 다시 보냅니다:

import asyncio

class EchoServerProtocol:
    def connection_made(self, transport):
        self.transport = transport

    def datagram_received(self, data, addr):
        message = data.decode()
        print('Received %r from %s' % (message, addr))
        print('Send %r to %s' % (message, addr))
        self.transport.sendto(data, addr)

async def main():
    print("Starting UDP server")

    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    # One protocol instance will be created to serve all
    # client requests.
    transport, protocol = await loop.create_datagram_endpoint(
        EchoServerProtocol,
        local_addr=('127.0.0.1', 9999))

    try:
        await asyncio.sleep(3600)  # Serve for 1 hour.
    finally:
        transport.close()

asyncio.run(main())

UDP 메아리 클라이언트

loop.create_datagram_endpoint() 메서드를 사용하는 UDP 메아리 클라이언트, 데이터를 보내고 응답을 받으면 트랜스포트를 닫습니다:

import asyncio

class EchoClientProtocol:
    def __init__(self, message, on_con_lost):
        self.message = message
        self.on_con_lost = on_con_lost
        self.transport = None

    def connection_made(self, transport):
        self.transport = transport
        print('Send:', self.message)
        self.transport.sendto(self.message.encode())

    def datagram_received(self, data, addr):
        print("Received:", data.decode())

        print("Close the socket")
        self.transport.close()

    def error_received(self, exc):
        print('Error received:', exc)

    def connection_lost(self, exc):
        print("Connection closed")
        self.on_con_lost.set_result(True)

async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    on_con_lost = loop.create_future()
    message = "Hello World!"

    transport, protocol = await loop.create_datagram_endpoint(
        lambda: EchoClientProtocol(message, on_con_lost),
        remote_addr=('127.0.0.1', 9999))

    try:
        await on_con_lost
    finally:
        transport.close()

asyncio.run(main())

기존 소켓 연결하기

프로토콜과 함께 loop.create_connection() 메서드를 사용하여 소켓이 데이터를 수신할 때까지 기다립니다:

import asyncio
import socket

class MyProtocol(asyncio.Protocol):

    def __init__(self, on_con_lost):
        self.transport = None
        self.on_con_lost = on_con_lost

    def connection_made(self, transport):
        self.transport = transport

    def data_received(self, data):
        print("Received:", data.decode())

        # We are done: close the transport;
        # connection_lost() will be called automatically.
        self.transport.close()

    def connection_lost(self, exc):
        # The socket has been closed
        self.on_con_lost.set_result(True)

async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()
    on_con_lost = loop.create_future()

    # Create a pair of connected sockets
    rsock, wsock = socket.socketpair()

    # Register the socket to wait for data.
    transport, protocol = await loop.create_connection(
        lambda: MyProtocol(on_con_lost), sock=rsock)

    # Simulate the reception of data from the network.
    loop.call_soon(wsock.send, 'abc'.encode())

    try:
        await protocol.on_con_lost
    finally:
        transport.close()
        wsock.close()

asyncio.run(main())

더 보기

파일 기술자에서 읽기 이벤트를 관찰하기 예제는 저수준의 loop.add_reader() 메서드를 사용하여 FD를 등록합니다.

스트림을 사용하여 데이터를 기다리는 열린 소켓 등록 예제는 코루틴에서 open_connection() 함수에 의해 생성된 고수준 스트림을 사용합니다.

loop.subprocess_exec() 와 SubprocessProtocol

서브 프로세스의 출력을 가져오고 서브 프로세스가 끝날 때까지 대기하는 데 사용되는 서브 프로세스 프로토콜의 예.

서브 프로세스는 loop.subprocess_exec() 메서드에 의해 만들어집니다:

import asyncio
import sys

class DateProtocol(asyncio.SubprocessProtocol):
    def __init__(self, exit_future):
        self.exit_future = exit_future
        self.output = bytearray()
        self.pipe_closed = False
        self.exited = False

    def pipe_connection_lost(self, fd, exc):
        self.pipe_closed = True
        self.check_for_exit()

    def pipe_data_received(self, fd, data):
        self.output.extend(data)

    def process_exited(self):
        self.exited = True
        # process_exited() method can be called before
        # pipe_connection_lost() method: wait until both methods are
        # called.
        self.check_for_exit()

    def check_for_exit(self):
        if self.pipe_closed and self.exited:
            self.exit_future.set_result(True)

async def get_date():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    code = 'import datetime; print(datetime.datetime.now())'
    exit_future = asyncio.Future(loop=loop)

    # Create the subprocess controlled by DateProtocol;
    # redirect the standard output into a pipe.
    transport, protocol = await loop.subprocess_exec(
        lambda: DateProtocol(exit_future),
        sys.executable, '-c', code,
        stdin=None, stderr=None)

    # Wait for the subprocess exit using the process_exited()
    # method of the protocol.
    await exit_future

    # Close the stdout pipe.
    transport.close()

    # Read the output which was collected by the
    # pipe_data_received() method of the protocol.
    data = bytes(protocol.output)
    return data.decode('ascii').rstrip()

date = asyncio.run(get_date())
print(f"Current date: {date}")

고수준 API를 사용하여 작성된 같은 예제도 참조하십시오.

정책

An event loop policy is a global object used to get and set the current event loop, as well as create new event loops. The default policy can be replaced with built-in alternatives to use different event loop implementations, or substituted by a custom policy that can override these behaviors.

The policy object gets and sets a separate event loop per context. This is per-thread by default, though custom policies could define context differently.

Custom event loop policies can control the behavior of get_event_loop(), set_event_loop(), and new_event_loop().

정책 객체는 AbstractEventLoopPolicy 추상 베이스 클래스에 정의된 API를 구현해야 합니다.

정책을 얻고 설정하기

다음 함수는 현재 프로세스의 정책을 가져오고 설정하는 데 사용할 수 있습니다:

asyncio.get_event_loop_policy()

현재의 프로세스 전반의 정책을 돌려줍니다.

asyncio.set_event_loop_policy(policy)

현재 프로세스 전반의 정책을 policy로 설정합니다.

policy를 None으로 설정하면, 기본 정책이 복원됩니다.

정책 객체

추상 이벤트 루프 정책 베이스 클래스는 다음과 같이 정의됩니다:

class asyncio.AbstractEventLoopPolicy

asyncio 정책의 추상 베이스 클래스.

get_event_loop()

현재 컨텍스트의 이벤트 루프를 가져옵니다.

AbstractEventLoop 인터페이스를 구현하는 이벤트 루프 객체를 반환합니다.

이 메서드는 절대 None을 반환해서는 안 됩니다.

버전 3.6에서 변경.

set_event_loop(loop)

현재 컨텍스트에 대한 이벤트 루프를 loop로 설정합니다.

new_event_loop()

새 이벤트 루프 객체를 만들고 반환합니다.

이 메서드는 절대 None을 반환해서는 안 됩니다.

asyncio에는 다음과 같은 내장 정책이 제공됩니다:

class asyncio.DefaultEventLoopPolicy

기본 asyncio 정책. 유닉스에서는 SelectorEventLoop를, 윈도우에서는 ProactorEventLoop를 사용합니다.

수동으로 기본 정책을 설치할 필요는 없습니다. asyncio는 기본 정책을 자동으로 사용하도록 구성됩니다.

버전 3.8에서 변경: 윈도우에서, 이제 기본적으로 ProactorEventLoop가 사용됩니다.

버전 3.14에서 변경: The get_event_loop() method of the default asyncio policy now raises a RuntimeError if there is no set event loop.

class asyncio.WindowsSelectorEventLoopPolicy

SelectorEventLoop 이벤트 루프 구현을 사용하는 대안 이벤트 루프 정책.

Availability: Windows.

class asyncio.WindowsProactorEventLoopPolicy

ProactorEventLoop 이벤트 루프 구현을 사용하는 대안 이벤트 루프 정책.

Availability: Windows.

사용자 정의 정책

새로운 이벤트 루프 정책을 구현하려면, DefaultEventLoopPolicy의 서브 클래스를 만들고 사용자 정의 동작이 필요한 메서드를 재정의하는 것이 좋습니다, 예를 들어:

class MyEventLoopPolicy(asyncio.DefaultEventLoopPolicy):

    def get_event_loop(self):
        """Get the event loop.

        This may be None or an instance of EventLoop.
        """
        loop = super().get_event_loop()
        # Do something with loop ...
        return loop

asyncio.set_event_loop_policy(MyEventLoopPolicy())

플랫폼 지원

asyncio 모듈은 이식성이 있도록 설계되었지만, 플랫폼의 하부 아키텍처와 기능으로 인해 일부 플랫폼에는 미묘한 차이점과 제약이 있습니다.

모든 플랫폼

loop.add_reader()와 loop.add_writer()는 파일 I/O를 감시하는데 사용할 수 없습니다.

윈도우

소스 코드: Lib/asyncio/proactor_events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/proactor_events.py], Lib/asyncio/windows_events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/windows_events.py], Lib/asyncio/windows_utils.py [https://github.com/python/cpython/tree/main/Lib/asyncio/windows_utils.py]

버전 3.8에서 변경: 윈도우에서, ProactorEventLoop는 이제 기본 이벤트 루프입니다.

윈도우의 모든 이벤트 루프는 다음 메서드를 지원하지 않습니다:

loop.create_unix_connection() and loop.create_unix_server() are not supported. The socket.AF_UNIX socket family is specific to Unix.

loop.add_signal_handler()와 loop.remove_signal_handler()는 지원되지 않습니다.

SelectorEventLoop에는 다음과 같은 제약이 있습니다:

SelectSelector는 소켓 이벤트를 기다리는 데 사용됩니다: 소켓을 지원하며 512개의 소켓으로 제한됩니다.

loop.add_reader()와 loop.add_writer()는 소켓 핸들만 받아들입니다 (예를 들어, 파이프 파일 기술자는 지원되지 않습니다).

파이프는 지원되지 않으므로, loop.connect_read_pipe()와 loop.connect_write_pipe() 메서드는 구현되지 않습니다.

서브 프로세스는 지원되지 않습니다, 즉, loop.subprocess_exec() 와 loop.subprocess_shell() 메서드가 구현되지 않습니다.

ProactorEventLoop에는 다음과 같은 제약이 있습니다:

loop.add_reader()와 loop.add_writer() 메서드는 지원되지 않습니다.

The resolution of the monotonic clock on Windows is usually around 15.6 milliseconds. The best resolution is 0.5 milliseconds. The resolution depends on the hardware (availability of HPET [https://en.wikipedia.org/wiki/High_Precision_Event_Timer]) and on the Windows configuration.

윈도우에서의 서브 프로세스 지원

윈도우에서, 기본 이벤트 루프 ProactorEventLoop는 서브 프로세스를 지원하지만, SelectorEventLoop는 그렇지 않습니다.

macOS

최신 macOS 버전은 완전하게 지원됩니다.

macOS <= 10.8

macOS 10.6, 10.7 및 10.8에서, 기본 이벤트 루프는 selectors.KqueueSelector를 사용하는데, 이 버전에서는 문자 장치를 지원하지 않습니다. 이러한 이전 버전의 macOS에서 문자 장치를 지원하려면, SelectorEventLoop가 SelectSelector 나 PollSelector를 사용하도록 수동으로 구성할 수 있습니다. 예:

import asyncio
import selectors

selector = selectors.SelectSelector()
loop = asyncio.SelectorEventLoop(selector)
asyncio.set_event_loop(loop)

Extending

The main direction for asyncio extending is writing custom event loop classes. Asyncio has helpers that could be used to simplify this task.

참고

Third-parties should reuse existing asyncio code with caution, a new Python version is free to break backward compatibility in internal part of API.

Writing a Custom Event Loop

asyncio.AbstractEventLoop declares very many methods. Implementing all them from scratch is a tedious job.

A loop can get many common methods implementation for free by inheriting from asyncio.BaseEventLoop.

In turn, the successor should implement a bunch of private methods declared but not implemented in asyncio.BaseEventLoop.

For example, loop.create_connection() checks arguments, resolves DNS addresses, and calls loop._make_socket_transport() that should be implemented by inherited class. The _make_socket_transport() method is not documented and is considered as an internal API.

Future and Task private constructors

asyncio.Future and asyncio.Task should be never created directly, please use corresponding loop.create_future() and loop.create_task(), or asyncio.create_task() factories instead.

However, third-party event loops may reuse built-in future and task implementations for the sake of getting a complex and highly optimized code for free.

For this purpose the following, private constructors are listed:

Future.__init__(*, loop=None)

Create a built-in future instance.

loop is an optional event loop instance.

Task.__init__(coro, *, loop=None, name=None, context=None)

Create a built-in task instance.

loop is an optional event loop instance. The rest of arguments are described in loop.create_task() description.

버전 3.11에서 변경: context argument is added.

Task lifetime support

A third party task implementation should call the following functions to keep a task visible by asyncio.all_tasks() and asyncio.current_task():

asyncio._register_task(task)

Register a new task as managed by asyncio.

Call the function from a task constructor.

asyncio._unregister_task(task)

Unregister a task from asyncio internal structures.

The function should be called when a task is about to finish.

asyncio._enter_task(loop, task)

Switch the current task to the task argument.

Call the function just before executing a portion of embedded coroutine (coroutine.send() or coroutine.throw()).

asyncio._leave_task(loop, task)

Switch the current task back from task to None.

Call the function just after coroutine.send() or coroutine.throw() execution.

고수준 API 색인

이 페이지에는 모든 고수준의 async/await 활성화된 asyncio API가 나열됩니다.

태스크

asyncio 프로그램을 실행하고, 태스크를 만들고, 시간제한 있게 여러 가지를 기다리는 유틸리티.

run()

이벤트 루프를 만들고, 코루틴을 실행하고, 루프를 닫습니다.

Runner

A context manager that simplifies multiple async function calls.

Task

Task 객체.

TaskGroup

A context manager that holds a group of tasks. Provides a convenient and reliable way to wait for all tasks in the group to finish.

create_task()

Start an asyncio Task, then returns it.

current_task()

현재 Task를 돌려줍니다.

all_tasks()

Return all tasks that are not yet finished for an event loop.

await sleep()

몇 초 동안 잠잡니다.

await gather()

여러 가지를 동시에 예약하고 기다립니다.

await wait_for()

시간제한 있게 실행합니다.

await shield()

취소로부터 보호합니다.

await wait()

완료를 감시합니다.

timeout()

Run with a timeout. Useful in cases when wait_for is not suitable.

to_thread()

Asynchronously run a function in a separate OS thread.

run_coroutine_threadsafe()

다른 OS 스레드에서 코루틴을 예약합니다.

for in as_completed()

for 루프로 완료를 감시합니다.

예제

여러 가지를 병렬로 실행하기 위해 asyncio.gather() 사용하기.

시간제한을 주기 위해 asyncio.wait_for() 사용하기.

취소.

asyncio.sleep() 사용하기.

주 태스크 설명서 페이지를 참조하십시오.

큐

큐는 여러 asyncio 태스크 간에 작업을 분산하고, 연결 풀과 pub/sub 패턴을 구현하는 데 사용해야 합니다.

Queue

FIFO 큐.

PriorityQueue

우선순위 큐.

LifoQueue

LIFO 큐.

예제

여러 태스크로 작업부하를 분산하는데 asyncio.Queue 사용하기.

큐 설명서 페이지도 참조하십시오.

서브 프로세스

서브 프로세스를 생성하고 셸 명령을 실행하는 유틸리티.

await create_subprocess_exec()

서브 프로세스를 만듭니다.

await create_subprocess_shell()

셸 명령을 실행합니다.

예제

셸 명령 실행하기.

서브 프로세스 API 설명서도 참조하십시오.

스트림

네트워크 IO로 작업하는 고수준 API

await open_connection()

TCP 연결을 만듭니다.

await open_unix_connection()

유닉스 소켓 연결을 만듭니다.

await start_server()

TCP 서버를 시작합니다.

await start_unix_server()

유닉스 소켓 서버를 시작합니다.

StreamReader

네트워크 데이터를 수신하는 고수준 async/await 객체.

StreamWriter

네트워크 데이터를 보내는 고수준 async/await 객체.

예제

예제 TCP 클라이언트.

스트림 API 설명서도 참조하십시오.

동기화

태스크에 쓸 수 있는 threading과 유사한 동기화 프리미티브.

Lock

뮤텍스 록.

Event

이벤트 객체.

Condition

조건 객체.

Semaphore

세마포어.

BoundedSemaphore

제한된 세마포어.

Barrier

A barrier object.

예제

asyncio.Event 사용하기.

Using asyncio.Barrier.

asyncio 동기화 프리미티브의 설명서도 참조하십시오.

예외

asyncio.CancelledError

Task가 취소될 때 발생합니다. Task.cancel()도 참조하십시오.

asyncio.BrokenBarrierError

Raised when a Barrier is broken. See also Barrier.wait().

예제

취소 요청 시에 코드를 실행하기 위해 CancelledError 처리하기.

asyncio 전용 예외의 전체 목록도 참조하십시오.

저수준 API 색인

이 페이지는 모든 저수준 asyncio API를 나열합니다.

이벤트 루프 얻기

asyncio.get_running_loop()

실행 중인 이벤트 루프를 가져오는 데 선호되는 함수.

asyncio.get_event_loop()

Get an event loop instance (running or current via the current policy).

asyncio.set_event_loop()

현재 정책을 통해 현재 이벤트 루프를 설정합니다.

asyncio.new_event_loop()

새 이벤트 루프를 만듭니다.

예제

asyncio.get_running_loop() 사용하기.

이벤트 루프 메서드

See also the main documentation section about the 이벤트 루프 메서드.

수명주기

loop.run_until_complete()

완료할 때까지 퓨처/태스크/어웨이터블을 실행합니다.

loop.run_forever()

이벤트 루프를 영원히 실행합니다.

loop.stop()

이벤트 루프를 중지합니다.

loop.close()

이벤트 루프를 닫습니다.

loop.is_running()

이벤트 루프가 실행 중이면 True를 반환합니다.

loop.is_closed()

이벤트 루프가 닫혔으면 True를 반환합니다.

await loop.shutdown_asyncgens()

비동기 제너레이터를 닫습니다.

디버깅

loop.set_debug()

디버그 모드를 활성화 또는 비활성화합니다.

loop.get_debug()

현재의 디버그 모드를 얻습니다.

콜백 예약하기

loop.call_soon()

콜백을 곧 호출합니다.

loop.call_soon_threadsafe()

스레드 안전한 loop.call_soon()의 변형입니다.

loop.call_later()

주어진 시간 후에 콜백을 호출합니다.

loop.call_at()

주어진 시간 에 콜백을 호출합니다.

Thread/Interpreter/Process Pool

await loop.run_in_executor()

concurrent.futures 실행기에서 CPU-병목이나 다른 블로킹 함수를 실행합니다.

loop.set_default_executor()

loop.run_in_executor()의 기본 실행기를 설정합니다.

태스크와 퓨처

loop.create_future()

Future 객체를 만듭니다.

loop.create_task()

코루틴을 Task로 예약합니다.

loop.set_task_factory()

loop.create_task()가 태스크를 만드는데 사용하는 팩토리를 설정합니다.

loop.get_task_factory()

loop.create_task()가 태스크를 만드는데 사용하는 팩토리를 얻습니다.

DNS

await loop.getaddrinfo()

socket.getaddrinfo()의 비동기 버전.

await loop.getnameinfo()

socket.getnameinfo()의 비동기 버전.

네트워킹과 IPC

await loop.create_connection()

TCP 연결을 엽니다.

await loop.create_server()

TCP 서버를 만듭니다.

await loop.create_unix_connection()

유닉스 소켓 연결을 엽니다.

await loop.create_unix_server()

Unix 소켓 서버를 만듭니다.

await loop.connect_accepted_socket()

socket을 (transport, protocol) 쌍으로 감쌉니다.

await loop.create_datagram_endpoint()

데이터 그램 (UDP) 연결을 엽니다.

await loop.sendfile()

트랜스포트를 통해 파일을 보냅니다.

await loop.start_tls()

기존 연결을 TLS로 업그레이드합니다.

await loop.connect_read_pipe()

파이프의 읽기 끝을 (transport, protocol) 쌍으로 감쌉니다.

await loop.connect_write_pipe()

파이프의 쓰기 끝을 (transport, protocol) 쌍으로 감쌉니다.

소켓

await loop.sock_recv()

socket에서 데이터를 수신합니다.

await loop.sock_recv_into()

socket에서 데이터를 버퍼로 수신합니다.

await loop.sock_recvfrom()

Receive a datagram from the socket.

await loop.sock_recvfrom_into()

Receive a datagram from the socket into a buffer.

await loop.sock_sendall()

데이터를 socket으로 보냅니다.

await loop.sock_sendto()

Send a datagram via the socket to the given address.

await loop.sock_connect()

socket을 연결합니다.

await loop.sock_accept()

socket 연결을 수락합니다.

await loop.sock_sendfile()

socket를 통해 파일을 보냅니다.

loop.add_reader()

파일 기술자가 읽기 가능한지 관찰하기 시작합니다.

loop.remove_reader()

파일 기술자가 읽기 가능한지 관찰하는 것을 중단합니다.

loop.add_writer()

파일 기술자가 쓰기 가능한지 관찰하기 시작합니다.

loop.remove_writer()

파일 기술자가 쓰기 가능한지 관찰하는 것을 중단합니다.

유닉스 시그널

loop.add_signal_handler()

signal에 대한 처리기를 추가합니다.

loop.remove_signal_handler()

signal에 대한 처리기를 제거합니다.

서브 프로세스

loop.subprocess_exec()

서브 프로세스를 스폰합니다.

loop.subprocess_shell()

셸 명령으로 서브 프로세스를 스폰합니다.

에러 처리

loop.call_exception_handler()

예외 처리기를 호출합니다.

loop.set_exception_handler()

새로운 예외 처리기를 설정합니다.

loop.get_exception_handler()

현재 예외 처리기를 가져옵니다.

loop.default_exception_handler()

기본 예외 처리기 구현.

예제

Using asyncio.new_event_loop() and loop.run_forever().

loop.call_later() 사용하기.

loop.create_connection()을 사용하여 메아리 클라이언트 구현하기.

loop.create_connection()을 사용하여 소켓 연결하기.

add_reader()를 사용하여 FD에서 읽기 이벤트 관찰하기.

loop.add_signal_handler() 사용하기.

loop.subprocess_exec() 사용하기.

트랜스포트

모든 트랜스포트는 다음과 같은 메서드를 구현합니다:

transport.close()

트랜스포트를 닫습니다.

transport.is_closing()

트랜스포트가 닫히고 있거나 닫혔으면 True를 반환합니다.

transport.get_extra_info()

트랜스포트에 대한 정보를 요청합니다.

transport.set_protocol()

새 프로토콜을 설정합니다.

transport.get_protocol()

현재 프로토콜을 돌려줍니다.

데이터를 받을 수 있는 트랜스포트 (TCP 및 유닉스 연결, 파이프 등). loop.create_connection(), loop.create_unix_connection(), loop.connect_read_pipe() 등의 메서드에서 반환됩니다:

트랜스포트 읽기

transport.is_reading()

트랜스포트가 수신 중이면 True를 반환합니다.

transport.pause_reading()

수신을 일시 정지합니다.

transport.resume_reading()

수신을 재개합니다.

데이터를 전송할 수 있는 트랜스포트 (TCP와 유닉스 연결, 파이프 등). loop.create_connection(), loop.create_unix_connection(), loop.connect_write_pipe() 등의 메서드에서 반환됩니다:

트랜스포트 쓰기

transport.write()

데이터를 트랜스포트에 씁니다.

transport.writelines()

버퍼들을 트랜스포트에 씁니다.

transport.can_write_eof()

트랜스포트가 EOF 전송을 지원하면 True를 반환합니다.

transport.write_eof()

버퍼 된 데이터를 플러시 한 후 닫고 EOF를 보냅니다.

transport.abort()

즉시 트랜스포트를 닫습니다.

transport.get_write_buffer_size()

Return the current size of the output buffer.

transport.get_write_buffer_limits()

쓰기 흐름 제어를 위한 높은 수위와 낮은 수위를 반환합니다.

transport.set_write_buffer_limits()

쓰기 흐름 제어를 위한 새로운 높은 수위와 낮은 수위를 설정합니다.

loop.create_datagram_endpoint()에서 반환된 트랜스포트:

데이터 그램 트랜스포트

transport.sendto()

데이터를 원격 피어로 보냅니다.

transport.abort()

즉시 트랜스포트를 닫습니다.

서브 프로세스에 대한 저수준 트랜스포트 추상화. loop.subprocess_exec() 와 loop.subprocess_shell()가 반환합니다:

서브 프로세스 트랜스포트

transport.get_pid()

서브 프로세스의 프로세스 ID를 돌려줍니다.

transport.get_pipe_transport()

요청한 통신 파이프 (stdin, stdout 또는 stderr)에 대한 트랜스포트를 반환합니다.

transport.get_returncode()

서브 프로세스 반환 코드를 돌려줍니다.

transport.kill()

서브 프로세스를 죽입니다.

transport.send_signal()

서브 프로세스에 시그널을 보냅니다.

transport.terminate()

서브 프로세스를 중지합니다.

transport.close()

서브 프로세스를 죽이고 모든 파이프를 닫습니다.

프로토콜

프로토콜 클래스는 다음 콜백 메서드를 구현할 수 있습니다:

callback connection_made()

연결이 이루어질 때 호출됩니다.

callback connection_lost()

연결이 끊어지거나 닫힐 때 호출됩니다.

callback pause_writing()

트랜스포트 버퍼가 높은 수위를 초과할 때 호출됩니다.

callback resume_writing()

트랜스포트 버퍼가 낮은 수위 아래로 내려갈 때 호출됩니다.

스트리밍 프로토콜 (TCP, 유닉스 소켓, 파이프)

callback data_received()

어떤 데이터가 수신될 때 호출됩니다.

callback eof_received()

EOF가 수신될 때 호출됩니다.

버퍼 된 스트리밍 프로토콜

callback get_buffer()

새로운 수신 버퍼를 할당하기 위해서 호출됩니다.

callback buffer_updated()

수신된 데이터로 버퍼가 갱신될 때 호출됩니다.

callback eof_received()

EOF가 수신될 때 호출됩니다.

데이터 그램 프로토콜

callback datagram_received()

데이터 그램이 수신될 때 호출됩니다.

callback error_received()

이전의 송신이나 수신 연산이 OSError를 일으킬 때 호출됩니다.

서브 프로세스 프로토콜

callback pipe_data_received()

자식 프로세스가 stdout 이나 stderr 파이프에 데이터를 쓸 때 호출됩니다.

callback pipe_connection_lost()

자식 프로세스와 통신하는 파이프 중 하나가 닫힐 때 호출됩니다.

callback process_exited()

Called when the child process has exited. It can be called before pipe_data_received() and pipe_connection_lost() methods.

이벤트 루프 정책

정책은 asyncio.get_event_loop()와 같은 함수의 동작을 변경하는 저수준 메커니즘입니다. 자세한 내용은 주 정책 절을 참조하십시오.

정책 액세스하기

asyncio.get_event_loop_policy()

현재 프로세스 전반의 정책을 돌려줍니다.

asyncio.set_event_loop_policy()

새로운 프로세스 전반의 정책을 설정합니다.

AbstractEventLoopPolicy

정책 객체의 베이스 클래스.

asyncio로 개발하기

비동기 프로그래밍은 고전적인 “순차적” 프로그래밍과 다릅니다.

이 페이지는 흔한 실수와 함정을 나열하고, 이를 피하는 방법을 설명합니다.

디버그 모드

기본적으로 asyncio는 프로덕션 모드로 실행됩니다. 개발을 쉽게 하려고 asyncio에는 디버그 모드를 제공합니다.

여러 가지 방법으로 asyncio 디버그 모드를 활성화할 수 있습니다:

PYTHONASYNCIODEBUG 환경 변수를 1로 설정.

파이썬 개발 모드 사용.

debug=True를 asyncio.run()로 전달.

loop.set_debug()를 호출.

디버그 모드를 활성화하는 것 외에도, 다음을 고려하십시오:

setting the log level of the asyncio logger to logging.DEBUG, for example the following snippet of code can be run at startup of the application:

logging.basicConfig(level=logging.DEBUG)

ResourceWarning 경고를 표시하도록 warnings 모듈을 구성. 이렇게 하는 한 가지 방법은 -W default 명령 줄 옵션을 사용하는 것입니다.

디버그 모드가 활성화되면:

asyncio는 기다리지 않은 코루틴을 검사하고 로그 합니다; 이것은 “잊힌 await” 함정을 완화합니다.

많은 스레드 안전하지 않은 asyncio API(loop.call_soon()과 loop.call_at() 메서드와 같은)가 잘못된 스레드에서 호출될 때 예외를 발생시킵니다.

I/O 선택기의 실행 시간은 I/O 연산 수행에 너무 오래 걸리면 로그 됩니다.

Callbacks taking longer than 100 milliseconds are logged. The loop.slow_callback_duration attribute can be used to set the minimum execution duration in seconds that is considered “slow”.

동시성과 다중 스레드

이벤트 루프는 스레드(일반적으로 주 스레드)에서 실행되며 그 스레드에서 모든 콜백과 태스크를 실행합니다. 태스크가 이벤트 루프에서 실행되는 동안, 다른 태스크는 같은 스레드에서 실행될 수 없습니다. 태스크가 await 표현식을 실행하면, 실행 중인 태스크가 일시 중지되고 이벤트 루프는 다음 태스크를 실행합니다.

다른 OS 스레드에서 콜백을 예약하려면, loop.call_soon_threadsafe() 메서드를 사용해야 합니다. 예:

loop.call_soon_threadsafe(callback, *args)

거의 모든 asyncio 객체는 스레드 안전하지 않습니다. 태스크나 콜백 외부에서 작동하는 코드가 없으면 일반적으로 문제가 되지 않습니다. 그러한 코드가 저수준 asyncio API를 호출해야 하면, loop.call_soon_threadsafe() 메서드를 사용해야 합니다, 예를 들어:

loop.call_soon_threadsafe(fut.cancel)

다른 OS 스레드에서 코루틴 객체를 예약하려면, run_coroutine_threadsafe() 함수를 사용해야 합니다. 결과에 액세스할 수 있도록 concurrent.futures.Future를 반환합니다:

async def coro_func():
     return await asyncio.sleep(1, 42)

# Later in another OS thread:

future = asyncio.run_coroutine_threadsafe(coro_func(), loop)
# Wait for the result:
result = future.result()

To handle signals the event loop must be run in the main thread.

The loop.run_in_executor() method can be used with a concurrent.futures.ThreadPoolExecutor or InterpreterPoolExecutor to execute blocking code in a different OS thread without blocking the OS thread that the event loop runs in.

There is currently no way to schedule coroutines or callbacks directly from a different process (such as one started with multiprocessing). The 이벤트 루프 메서드 section lists APIs that can read from pipes and watch file descriptors without blocking the event loop. In addition, asyncio’s Subprocess APIs provide a way to start a process and communicate with it from the event loop. Lastly, the aforementioned loop.run_in_executor() method can also be used with a concurrent.futures.ProcessPoolExecutor to execute code in a different process.

블로킹 코드 실행하기

블로킹 (CPU 병목) 코드는 직접 호출하면 안 됩니다. 예를 들어, 함수가 CPU 집약적인 계산을 1초 동안 수행하면, 모든 동시 asyncio 태스크와 IO 연산이 1초 지연됩니다.

An executor can be used to run a task in a different thread, including in a different interpreter, or even in a different process to avoid blocking the OS thread with the event loop. See the loop.run_in_executor() method for more details.

로깅

asyncio는 logging 모듈을 사용하고, 모든 로깅은 "asyncio" 로거를 통해 수행됩니다.

The default log level is logging.INFO, which can be easily adjusted:

logging.getLogger("asyncio").setLevel(logging.WARNING)

Network logging can block the event loop. It is recommended to use a separate thread for handling logs or use non-blocking IO. For example, see 블록 하는 처리기 다루기.

await 하지 않은 코루틴 감지

코루틴 함수가 호출되었지만 기다리지 않을 때(예를 들어, await coro() 대신 coro())나 코루틴이 asyncio.create_task()로 예약되지 않으면 asyncio가 RuntimeWarning을 방출합니다:

import asyncio

async def test():
    print("never scheduled")

async def main():
    test()

asyncio.run(main())

출력:

test.py:7: RuntimeWarning: coroutine 'test' was never awaited
  test()

디버그 모드에서의 출력:

test.py:7: RuntimeWarning: coroutine 'test' was never awaited
Coroutine created at (most recent call last)
  File "../t.py", line 9, in <module>
    asyncio.run(main(), debug=True)

  < .. >

  File "../t.py", line 7, in main
    test()
  test()

일반적인 수정법은 코루틴을 await 하거나 asyncio.create_task() 함수를 호출하는 것입니다:

async def main():
    await test()

전달되지 않은 예외 감지

Future.set_exception()가 호출되었지만, Future 객체가 await 되지 않으면, 예외는 절대로 사용자 코드로 전파되지 않습니다. 이럴 때, Future 객체가 가비지 수집될 때 asyncio가 로그 메시지를 출력합니다.

처리되지 않은 예외의 예:

import asyncio

async def bug():
    raise Exception("not consumed")

async def main():
    asyncio.create_task(bug())

asyncio.run(main())

출력:

Task exception was never retrieved
future: <Task finished coro=<bug() done, defined at test.py:3>
  exception=Exception('not consumed')>

Traceback (most recent call last):
  File "test.py", line 4, in bug
    raise Exception("not consumed")
Exception: not consumed

태스크가 만들어진 곳의 트레이스백을 얻으려면 디버그 모드를 활성화하세요:

asyncio.run(main(), debug=True)

디버그 모드에서의 출력:

Task exception was never retrieved
future: <Task finished coro=<bug() done, defined at test.py:3>
    exception=Exception('not consumed') created at asyncio/tasks.py:321>

source_traceback: Object created at (most recent call last):
  File "../t.py", line 9, in <module>
    asyncio.run(main(), debug=True)

< .. >

Traceback (most recent call last):
  File "../t.py", line 4, in bug
    raise Exception("not consumed")
Exception: not consumed

socket — Low-level networking interface

소스 코드: Lib/socket.py [https://github.com/python/cpython/tree/main/Lib/socket.py]

이 모듈은 BSD socket 인터페이스에 대한 액세스를 제공합니다. 모든 현대 유닉스 시스템, 윈도우, MacOS, 그리고 아마 추가 플랫폼에서 사용할 수 있습니다.

참고

호출이 운영 체제 소켓 API로 이루어지기 때문에, 일부 동작은 플랫폼에 따라 다를 수 있습니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

The Python interface is a straightforward transliteration of the Unix system call and library interface for sockets to Python’s object-oriented style: the socket() function returns a socket object whose methods implement the various socket system calls. Parameter types are somewhat higher-level than in the C interface: as with read() and write() operations on Python files, buffer allocation on receive operations is automatic, and buffer length is implicit on send operations.

더 보기

모듈 socketserver

네트워크 서버 작성을 단순화하는 클래스.

모듈 ssl

소켓 객체용 TLS/SSL 래퍼.

소켓 패밀리

시스템과 빌드 옵션에 따라, 다양한 소켓 패밀리가 이 모듈에서 지원됩니다.

특정 소켓 객체가 요구하는 주소 형식은 소켓 객체를 만들 때 지정된 주소 패밀리에 따라 자동으로 선택됩니다. 소켓 주소는 다음과 같이 표현됩니다:

파일 시스템 노드에 바인드 된 AF_UNIX 소켓의 주소는 파일 시스템 인코딩과 'surrogateescape' 에러 처리기(PEP 383 [https://peps.python.org/pep-0383/]을 참조하세요)를 사용하는 문자열로 표현됩니다. 리눅스의 추상 이름 공간(abstract namespace)에 있는 주소는 처음에 널 바이트가 있는 바이트열류 객체로 반환됩니다; 이 이름 공간의 소켓은 일반 파일 시스템 소켓과 통신 할 수 있으므로, 리눅스에서 실행하려는 프로그램은 두 가지 유형의 주소를 모두 다뤄야 할 수도 있습니다. 문자열이나 바이트열류 객체는 인자로 전달할 때 두 가지 유형의 주소에 모두 사용할 수 있습니다.

버전 3.3에서 변경: 이전에는, AF_UNIX 소켓 경로가 UTF-8 인코딩을 사용한다고 가정했습니다.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

A pair (host, port) is used for the AF_INET address family, where host is a string representing either a hostname in internet domain notation like 'daring.cwi.nl' or an IPv4 address like '100.50.200.5', and port is an integer.

IPv4 주소의 경우, 호스트 주소 대신 두 개의 특수 형식이 허용됩니다: ''는 모든 인터페이스에 바인딩하는 데 사용되는 INADDR_ANY를 나타내며 '<broadcast>' 문자열은 INADDR_BROADCAST를 나타냅니다. 이 동작은 IPv6와 호환되지 않으므로, 여러분의 파이썬 프로그램에서 IPv6를 지원하려는 경우에는 이것들을 사용하지 않을 수 있습니다.

AF_INET6 주소 패밀리의 경우, 4-튜플 (host, port, flowinfo, scope_id)가 사용됩니다. 여기서 flowinfo 와 scope_id는 C에서 struct sockaddr_in6의 sin6_flowinfo 와 sin6_scope_id 멤버를 나타냅니다. socket 모듈 메서드의 경우, flowinfo 와 scope_id는 이전 버전과의 호환성을 위해 생략할 수 있습니다. 그러나, scope_id를 생략하면 스코프가 지정된(scoped) IPv6 주소를 조작하는 데 문제가 발생할 수 있습니다.

버전 3.7에서 변경: 멀티캐스트 주소(의미 있는 scope_id를 가진)의 경우, address에는 %scope_id (또는 zone id) 부분이 포함될 수 없습니다. 이 정보는 불필요하므로 안전하게 생략할 수 있습니다 (권장 사항).

AF_NETLINK 소켓은 (pid, groups) 쌍으로 표현됩니다.

TIPC에 대한 리눅스 전용 지원은 AF_TIPC 주소 패밀리를 사용하여 사용할 수 있습니다. TIPC는 클러스터 된 컴퓨터 환경에서 사용하도록 설계된 개방형 비 IP 기반 네트워크 프로토콜입니다. 주소는 튜플로 표현되며 필드는 주소 유형에 따라 다릅니다. 일반적인 튜플 형식은 (addr_type, v1, v2, v3 [, scope])입니다. 이때:

addr_type은 TIPC_ADDR_NAMESEQ, TIPC_ADDR_NAME 또는 TIPC_ADDR_ID 중 하나입니다.

scope는 TIPC_ZONE_SCOPE, TIPC_CLUSTER_SCOPE 또는 TIPC_NODE_SCOPE 중 하나입니다.

addr_type이 TIPC_ADDR_NAME이면, v1은 서버 유형이고, v2는 포트 식별자이며, v3은 0이어야 합니다.

addr_type이 TIPC_ADDR_NAMESEQ면, v1은 서버 유형이고, v2는 하위 포트 번호이며, v3는 상위 포트 번호입니다.

addr_type이 TIPC_ADDR_ID면, v1은 노드이고, v2는 참조이며, v3는 0으로 설정되어야 합니다.

튜플 (interface, )가 AF_CAN 주소 패밀리에 사용됩니다. 여기서 interface는 'can0'과 같은 네트워크 인터페이스 이름을 나타내는 문자열입니다. 네트워크 인터페이스 이름 ''는 이 패밀리의 모든 네트워크 인터페이스에서 패킷을 수신하는 데 사용할 수 있습니다.

CAN_ISOTP 프로토콜은 튜플 (interface, rx_addr, tx_addr)를 요구하는데, 두 개의 추가 매개 변수는 모두 CAN 식별자(표준 또는 확장)를 나타내는 부호 없는 long 정수입니다.

CAN_J1939 프로토콜에는 (interface, name, pgn, addr)가 필요한데, 여기서 추가 파라미터는 ECU 이름을 나타내는 64 비트 부호 없는 정수, PGN(Parameter Group Number)을 나타내는 32비트 부호 없는 정수 및 주소를 나타내는 8비트 정수입니다.

A string or a tuple (id, unit) is used for the SYSPROTO_CONTROL protocol of the PF_SYSTEM family. The string is the name of a kernel control using a dynamically assigned ID. The tuple can be used if ID and unit number of the kernel control are known or if a registered ID is used.

Added in version 3.3.

AF_BLUETOOTH는 다음 프로토콜 및 주소 형식을 지원합니다:

BTPROTO_L2CAP는 (bdaddr, psm)를 받아들입니다. 여기서 bdaddr은 문자열 블루투스 주소이고 psm은 정수입니다.

BTPROTO_RFCOMM은 (bdaddr, channel)를 받아들입니다. 여기서 bdaddr은 문자열 블루투스 주소이고 channel은 정수입니다.

BTPROTO_HCI는 (device_id,)를 받아들입니다. 여기서 device_id는 정수나 인터페이스의 블루투스 주소인 문자열입니다. (이것은 여러분의 OS에 따라 다릅니다; NetBSD와 FreeBSD는 블루투스 주소를 기대하지만 다른 모든 것은 정수를 기대합니다.)

버전 3.2에서 변경: NetBSD 및 DragonFlyBSD 지원이 추가되었습니다.

BTPROTO_SCO는 bdaddr를 받아들입니다. 여기서 bdaddr는 블루투스 주소의 문자열 형식이 포함된 bytes 객체입니다. (예, b'12:23:34:45:56:67') 이 프로토콜은 FreeBSD에서 지원되지 않습니다.

AF_ALG는 커널 암호 인터페이스에 기반한 리눅스 전용 소켓입니다. 알고리즘 소켓은 2~4개의 요소를 갖는 (type, name [, feat [, mask]]) 튜플로 구성됩니다. 여기서:

type은 문자열의 알고리즘 유형입니다, 예를 들어, aead, hash, skcipher 또는 rng.

name은 알고리즘 이름과 연산 모드 문자열입니다, 예를 들어, sha256, hmac(sha256), cbc(aes) 또는 drbg_nopr_ctr_aes256.

feat 과 mask는 부호 없는 32비트 정수입니다.

Availability: Linux >= 2.6.38.

Some algorithm types require more recent Kernels.

Added in version 3.6.

AF_VSOCK은 가상 기계와 호스트가 통신할 수 있게 합니다. 소켓은 (CID, port) 튜플로 표현되는데, 컨텍스트 ID 또는 CID와 port는 정수입니다.

Availability: Linux >= 3.9

See vsock(7) [https://manpages.debian.org/vsock(7)]

Added in version 3.7.

AF_PACKET is a low-level interface directly to network devices. The addresses are represented by the tuple (ifname, proto[, pkttype[, hatype[, addr]]]) where:

ifname - 장치 이름을 지정하는 문자열

proto - The Ethernet protocol number. May be ETH_P_ALL to capture all protocols, one of the ETHERTYPE_* constants or any other Ethernet protocol number.

pkttype - 패킷 유형을 지정하는 선택적 정수.:

PACKET_HOST (기본값) - 로컬 호스트로 향하는 패킷.

PACKET_BROADCAST - 물리 계층 브로드캐스트 패킷.

PACKET_MULTICAST - Packet sent to a physical-layer multicast address.

PACKET_OTHERHOST - 무차별 모드의 장치 관리자에 의해 포착된 다른 호스트로 향하는 패킷.

PACKET_OUTGOING - 패킷 소켓으로 루프 백 된 로컬 호스트에서 시작된 패킷.

hatype - ARP 하드웨어 주소 유형을 지정하는 선택적 정수.

addr - 하드웨어 물리 주소를 지정하는 선택적 바이트열류 객체, 해석은 장치에 따라 다릅니다.

Availability: Linux >= 2.2.

AF_QIPCRTR는 Qualcomm 플랫폼의 코 프로세서에서 실행되는 서비스와 통신하기 위한 리눅스 전용 소켓 기반 인터페이스입니다. 주소 패밀리는 (node, port) 튜플로 표현되는데, node와 port는 음수가 아닌 정수입니다.

Availability: Linux >= 4.7.

Added in version 3.8.

IPPROTO_UDPLITE는 UDP의 변형으로, 체크섬으로 커버되는 패킷 부분을 지정할 수 있습니다. 변경할 수 있는 두 개의 소켓 옵션이 추가되었습니다. self.setsockopt(IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV, length)는 체크섬으로 커버되는 나가는 패킷 부분을 변경하고 self.setsockopt(IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV, length)는 너무 적은 데이터를 커버하는 패킷을 걸러냅니다. 두 경우 모두 length는 range(8, 2**16, 8)에 있어야합니다.

이러한 소켓은 IPv4의 경우 socket(AF_INET, SOCK_DGRAM, IPPROTO_UDPLITE) 또는 IPv6의 경우 socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE)로 구성되어야 합니다.

Availability: Linux >= 2.6.20, FreeBSD >= 10.1

Added in version 3.9.

AF_HYPERV is a Windows-only socket based interface for communicating with Hyper-V hosts and guests. The address family is represented as a (vm_id, service_id) tuple where the vm_id and service_id are UUID strings.

The vm_id is the virtual machine identifier or a set of known VMID values if the target is not a specific virtual machine. Known VMID constants defined on socket are:

HV_GUID_ZERO

HV_GUID_BROADCAST

HV_GUID_WILDCARD - Used to bind on itself and accept connections from all partitions.

HV_GUID_CHILDREN - Used to bind on itself and accept connection from child partitions.

HV_GUID_LOOPBACK - Used as a target to itself.

HV_GUID_PARENT - When used as a bind accepts connection from the parent partition. When used as an address target it will connect to the parent partition.

The service_id is the service identifier of the registered service.

Added in version 3.12.

IPv4/v6 소켓 주소의 host 부분에 호스트 명을 사용하면, 파이썬이 DNS 결정에서 반환된 첫 번째 주소를 사용하기 때문에, 프로그램은 비결정적인 동작을 보일 수 있습니다. 소켓 주소는 DNS 결정 결과 및/또는 호스트 구성에 따라 실제 IPv4/v6 주소로 다르게 결정됩니다. 결정론적 동작을 위해서는 host 부분에 숫자 주소를 사용하십시오.

All errors raise exceptions. The normal exceptions for invalid argument types and out-of-memory conditions can be raised. Errors related to socket or address semantics raise OSError or one of its subclasses.

비 블로킹 모드는 setblocking()을 통해 지원됩니다. 시간제한을 기반으로 하는 일반화는 settimeout()을 통해 지원됩니다.

모듈 내용

모듈 socket은 다음 요소를 노출합니다.

예외

exception socket.error

OSError의 폐지된 별칭.

버전 3.3에서 변경: PEP 3151 [https://peps.python.org/pep-3151/]을 따라, 이 클래스는 OSError의 별칭이 되었습니다.

exception socket.herror

OSError의 서브 클래스, 이 예외는 주소 관련 에러에서 발생합니다. 즉 gethostbyname_ex()와 gethostbyaddr()를 포함하는 POSIX C API의 h_errno를 사용하는 함수들. 수반되는 값은 라이브러리 호출이 반환한 에러를 나타내는 (h_errno, string) 쌍입니다. h_errno는 숫자 값이고, string은 hstrerror() C 함수에 의해 반환된 h_errno의 설명을 나타냅니다.

버전 3.3에서 변경: 이 클래스는 OSError의 서브 클래스가 되었습니다.

exception socket.gaierror

A subclass of OSError, this exception is raised for address-related errors by getaddrinfo() and getnameinfo(). The accompanying value is a pair (error, string) representing an error returned by a library call. string represents the description of error, as returned by the gai_strerror() C function. The numeric error value will match one of the EAI_* constants defined in this module.

버전 3.3에서 변경: 이 클래스는 OSError의 서브 클래스가 되었습니다.

exception socket.timeout

A deprecated alias of TimeoutError.

OSError의 서브 클래스, 이 예외는 앞서 settimeout() 호출을 통해 (또는 묵시적으로 setdefaulttimeout()를 통해) 시간제한이 활성화된 소켓에서 시간 초과가 일어날 때 발생합니다. 수반되는 값은 현재는 항상 “timed out” 값을 갖는 문자열입니다.

버전 3.3에서 변경: 이 클래스는 OSError의 서브 클래스가 되었습니다.

버전 3.10에서 변경: This class was made an alias of TimeoutError.

상수

AF_* 와 SOCK_* 상수는 이제 AddressFamily 와 SocketKind IntEnum 컬렉션입니다.

Added in version 3.4.

socket.AF_UNIX

socket.AF_INET

socket.AF_INET6

These constants represent the address (and protocol) families, used for the first argument to socket(). If the AF_UNIX constant is not defined then this protocol is unsupported. More constants may be available depending on the system.

socket.AF_UNSPEC

AF_UNSPEC means that getaddrinfo() should return socket addresses for any address family (either IPv4, IPv6, or any other) that can be used.

socket.SOCK_STREAM

socket.SOCK_DGRAM

socket.SOCK_RAW

socket.SOCK_RDM

socket.SOCK_SEQPACKET

These constants represent the socket types, used for the second argument to socket(). More constants may be available depending on the system. (Only SOCK_STREAM and SOCK_DGRAM appear to be generally useful.)

socket.SOCK_CLOEXEC

socket.SOCK_NONBLOCK

이 두 상수는, 정의되었다면, 소켓 유형과 결합하여 일부 플래그를 원자 적으로 설정할 수 있도록 합니다 (따라서 경쟁 조건의 가능성과 별도 호출의 필요성을 피할 수 있습니다).

더 보기

Secure File Descriptor Handling [https://udrepper.livejournal.com/20407.html] for a more thorough explanation.

Availability: Linux >= 2.6.27.

Added in version 3.2.

SO_*

socket.SOMAXCONN

MSG_*

SOL_*

SCM_*

IPPROTO_*

IPPORT_*

INADDR_*

IP_*

IPV6_*

EAI_*

AI_*

NI_*

TCP_*

Many constants of these forms, documented in the Unix documentation on sockets and/or the IP protocol, are also defined in the socket module. They are generally used in arguments to the setsockopt() and getsockopt() methods of socket objects. In most cases, only those symbols that are defined in the Unix header files are defined; for a few symbols, default values are provided.

버전 3.6에서 변경: SO_DOMAIN, SO_PROTOCOL, SO_PEERSEC, SO_PASSSEC, TCP_USER_TIMEOUT, TCP_CONGESTION가 추가되었습니다.

버전 3.6.5에서 변경: Added support for TCP_FASTOPEN, TCP_KEEPCNT on Windows platforms when available.

버전 3.7에서 변경: TCP_NOTSENT_LOWAT가 추가되었습니다.

Added support for TCP_KEEPIDLE, TCP_KEEPINTVL on Windows platforms when available.

버전 3.10에서 변경: IP_RECVTOS was added. Added TCP_KEEPALIVE. On MacOS this constant can be used in the same way that TCP_KEEPIDLE is used on Linux.

버전 3.11에서 변경: Added TCP_CONNECTION_INFO. On MacOS this constant can be used in the same way that TCP_INFO is used on Linux and BSD.

버전 3.12에서 변경: Added SO_RTABLE and SO_USER_COOKIE. On OpenBSD and FreeBSD respectively those constants can be used in the same way that SO_MARK is used on Linux. Also added missing TCP socket options from Linux: TCP_MD5SIG, TCP_THIN_LINEAR_TIMEOUTS, TCP_THIN_DUPACK, TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS, TCP_TIMESTAMP, TCP_CC_INFO, TCP_SAVE_SYN, TCP_SAVED_SYN, TCP_REPAIR_WINDOW, TCP_FASTOPEN_CONNECT, TCP_ULP, TCP_MD5SIG_EXT, TCP_FASTOPEN_KEY, TCP_FASTOPEN_NO_COOKIE, TCP_ZEROCOPY_RECEIVE, TCP_INQ, TCP_TX_DELAY. Added IP_PKTINFO, IP_UNBLOCK_SOURCE, IP_BLOCK_SOURCE, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_SOURCE_MEMBERSHIP.

버전 3.13에서 변경: Added SO_BINDTOIFINDEX. On Linux this constant can be used in the same way that SO_BINDTODEVICE is used, but with the index of a network interface instead of its name.

버전 3.14에서 변경: Added missing IP_RECVERR, IPV6_RECVERR, IP_RECVTTL, and IP_RECVORIGDSTADDR on Linux.

버전 3.14에서 변경: Added support for TCP_QUICKACK on Windows platforms when available.

socket.AF_CAN

socket.PF_CAN

SOL_CAN_*

CAN_*

리눅스 설명서에 설명되어있는 이 형식의 많은 상수는 소켓 모듈에도 정의되어 있습니다.

Availability: Linux >= 2.6.25, NetBSD >= 8.

Added in version 3.3.

버전 3.11에서 변경: NetBSD support was added.

socket.CAN_BCM

CAN_BCM_*

CAN 프로토콜 패밀리에서 CAN_BCM은 브로드캐스트 관리자 (Broadcast Manager, BCM) 프로토콜입니다. 리눅스 설명서에서 설명된 브로드캐스트 관리자 상수도 소켓 모듈에 정의되어 있습니다.

Availability: Linux >= 2.6.25.

참고

CAN_BCM_CAN_FD_FRAME 플래그는 리눅스 >= 4.8 에서만 사용 가능합니다.

Added in version 3.4.

socket.CAN_RAW_FD_FRAMES

CAN_RAW 소켓에서 CAN FD 지원을 활성화합니다. 기본적으로 비활성화되어 있습니다. 여러분의 응용 프로그램이 CAN과 CAN FD 프레임을 모두 보낼 수 있도록 합니다; 그러나 소켓에서 읽을 때 CAN과 CAN FD 프레임을 모두 받아들여야 합니다.

이 상수는 리눅스 설명서에 설명되어 있습니다.

Availability: Linux >= 3.6.

Added in version 3.5.

socket.CAN_RAW_JOIN_FILTERS

주어진 모든 CAN 필터와 일치하는 CAN 프레임 만 사용자 공간으로 전달되도록 적용된 CAN 필터를 결합합니다.

이 상수는 리눅스 설명서에 설명되어 있습니다.

Availability: Linux >= 4.1.

Added in version 3.9.

socket.CAN_ISOTP

CAN 프로토콜 패밀리의 CAN_ISOTP는 ISO-TP (ISO 15765-2) 프로토콜입니다. ISO-TP 상수는 리눅스 설명서에 설명되어 있습니다.

Availability: Linux >= 2.6.25.

Added in version 3.7.

socket.CAN_J1939

CAN 프로토콜 패밀리의 CAN_J1939는 SAE J1939 프로토콜입니다. J1939 상수는 리눅스 설명서에 설명되어 있습니다.

Availability: Linux >= 5.4.

Added in version 3.9.

socket.AF_DIVERT

socket.PF_DIVERT

These two constants, documented in the FreeBSD divert(4) manual page, are also defined in the socket module.

Availability: FreeBSD >= 14.0.

Added in version 3.12.

socket.AF_PACKET

socket.PF_PACKET

PACKET_*

리눅스 설명서에 설명되어있는 이 형식의 많은 상수는 소켓 모듈에도 정의되어 있습니다.

Availability: Linux >= 2.2.

socket.ETH_P_ALL

ETH_P_ALL can be used in the socket constructor as proto for the AF_PACKET family in order to capture every packet, regardless of protocol.

For more information, see the packet(7) [https://manpages.debian.org/packet(7)] manpage.

Availability: Linux.

Added in version 3.12.

socket.AF_RDS

socket.PF_RDS

socket.SOL_RDS

RDS_*

리눅스 설명서에 설명되어있는 이 형식의 많은 상수는 소켓 모듈에도 정의되어 있습니다.

Availability: Linux >= 2.6.30.

Added in version 3.3.

socket.SIO_RCVALL

socket.SIO_KEEPALIVE_VALS

socket.SIO_LOOPBACK_FAST_PATH

RCVALL_*

윈도우 WSAIoctl()용 상수. 이 상수는 소켓 객체의 ioctl() 메서드에 대한 인자로 사용됩니다.

버전 3.6에서 변경: SIO_LOOPBACK_FAST_PATH가 추가되었습니다.

TIPC_*

TIPC 관련 상수. C 소켓 API에서 내보낸 것과 일치합니다. 자세한 정보는 TIPC 설명서를 참조하십시오.

socket.AF_ALG

socket.SOL_ALG

ALG_*

리눅스 커널 암호화용 상수.

Availability: Linux >= 2.6.38.

Added in version 3.6.

socket.AF_VSOCK

socket.IOCTL_VM_SOCKETS_GET_LOCAL_CID

VMADDR*

SO_VM*

리눅스 호스트/게스트 통신용 상수.

Availability: Linux >= 4.8.

Added in version 3.7.

socket.AF_LINK

Availability: BSD, macOS.

Added in version 3.4.

socket.has_ipv6

이 상수는 이 플랫폼에서 IPv6가 지원되는지를 나타내는 논릿값을 포함합니다.

socket.BDADDR_ANY

socket.BDADDR_LOCAL

이들은 특수한 의미를 지닌 블루투스 주소를 포함하는 문자열 상수입니다. 예를 들어, BDADDR_ANY는 바인딩 소켓을 BTPROTO_RFCOMM로 지정할 때 임의의(any) 주소를 나타내는 데 사용할 수 있습니다.

socket.HCI_FILTER

socket.HCI_TIME_STAMP

socket.HCI_DATA_DIR

BTPROTO_HCI와 함께 사용하십시오. NetBSD 나 DragonFlyBSD에서는 HCI_FILTER를 사용할 수 없습니다. HCI_TIME_STAMP와 HCI_DATA_DIR는 FreeBSD, NetBSD 또는 DragonFlyBSD에서 사용할 수 없습니다.

socket.AF_QIPCRTR

원격 프로세서를 제공하는 서비스와 통신하는 데 사용되는 Qualcomm의 IPC 라우터 프로토콜용 상수.

Availability: Linux >= 4.7.

socket.SCM_CREDS2

socket.LOCAL_CREDS

socket.LOCAL_CREDS_PERSISTENT

LOCAL_CREDS and LOCAL_CREDS_PERSISTENT can be used with SOCK_DGRAM, SOCK_STREAM sockets, equivalent to Linux/DragonFlyBSD SO_PASSCRED, while LOCAL_CREDS sends the credentials at first read, LOCAL_CREDS_PERSISTENT sends for each read, SCM_CREDS2 must be then used for the latter for the message type.

Added in version 3.11.

Availability: FreeBSD.

socket.SO_INCOMING_CPU

Constant to optimize CPU locality, to be used in conjunction with SO_REUSEPORT.

Added in version 3.11.

Availability: Linux >= 3.9

socket.AF_HYPERV

socket.HV_PROTOCOL_RAW

socket.HVSOCKET_CONNECT_TIMEOUT

socket.HVSOCKET_CONNECT_TIMEOUT_MAX

socket.HVSOCKET_CONNECTED_SUSPEND

socket.HVSOCKET_ADDRESS_FLAG_PASSTHRU

socket.HV_GUID_ZERO

socket.HV_GUID_WILDCARD

socket.HV_GUID_BROADCAST

socket.HV_GUID_CHILDREN

socket.HV_GUID_LOOPBACK

socket.HV_GUID_PARENT

Constants for Windows Hyper-V sockets for host/guest communications.

Availability: Windows.

Added in version 3.12.

socket.ETHERTYPE_ARP

socket.ETHERTYPE_IP

socket.ETHERTYPE_IPV6

socket.ETHERTYPE_VLAN

IEEE 802.3 protocol number [https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.txt]. constants.

Availability: Linux, FreeBSD, macOS.

Added in version 3.12.

socket.SHUT_RD

socket.SHUT_WR

socket.SHUT_RDWR

These constants are used by the shutdown() method of socket objects.

Availability: not WASI.

함수

소켓 만들기

다음 함수는 모두 소켓 객체를 만듭니다.

class socket.socket(family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None)

지정된 주소 패밀리, 소켓 유형, 및 프로토콜 번호를 사용하여 새로운 소켓을 만듭니다. 주소 패밀리는 AF_INET (기본값), AF_INET6, AF_UNIX, AF_CAN, AF_PACKET 또는 AF_RDS 여야 합니다. 소켓 유형은 SOCK_STREAM (기본값), SOCK_DGRAM, SOCK_RAW 또는 기타 SOCK_ 상수 중 하나여야 합니다. 프로토콜 번호는 일반적으로 0이며 생략될 수도 있고, 주소 패밀리가 AF_CAN 일 때 프로토콜은 CAN_RAW, CAN_BCM, CAN_ISOTP 또는 CAN_J1939 중 하나여야 합니다.

If fileno is specified, the values for family, type, and proto are auto-detected from the specified file descriptor. Auto-detection can be overruled by calling the function with explicit family, type, or proto arguments. This only affects how Python represents e.g. the return value of socket.getpeername() but not the actual OS resource. Unlike socket.fromfd(), fileno will return the same socket and not a duplicate. This may help close a detached socket using socket.close().

새로 만들어진 소켓은 상속 불가능합니다.

self, family, type, protocol를 인자로 감사 이벤트(auditing event) socket.__new__를 발생시킵니다.

버전 3.3에서 변경: AF_CAN 패밀리가 추가되었습니다. AF_RDS 패밀리가 추가되었습니다.

버전 3.4에서 변경: CAN_BCM 프로토콜이 추가되었습니다.

버전 3.4에서 변경: 반환된 소켓은 이제 상속 불가능합니다.

버전 3.7에서 변경: CAN_ISOTP 프로토콜이 추가되었습니다.

버전 3.7에서 변경: When SOCK_NONBLOCK or SOCK_CLOEXEC bit flags are applied to type they are cleared, and socket.type will not reflect them. They are still passed to the underlying system socket() call. Therefore,

sock = socket.socket(
    socket.AF_INET,
    socket.SOCK_STREAM | socket.SOCK_NONBLOCK)

는 여전히 SOCK_NONBLOCK를 지원하는 OS에서 비 블로킹 소켓을 만들지만, sock.type은 socket.SOCK_STREAM로 설정됩니다.

버전 3.9에서 변경: CAN_J1939 프로토콜이 추가되었습니다.

버전 3.10에서 변경: The IPPROTO_MPTCP protocol was added.

socket.socketpair([family[, type[, proto]]])

Build a pair of connected socket objects using the given address family, socket type, and protocol number. Address family, socket type, and protocol number are as for the socket() function above. The default family is AF_UNIX if defined on the platform; otherwise, the default is AF_INET.

새로 만들어진 소켓은 상속 불가능합니다.

버전 3.2에서 변경: 반환된 소켓 객체는 이제 부분 집합이 아닌 전체 소켓 API를 지원합니다.

버전 3.4에서 변경: 반환된 소켓은 이제 상속 불가능합니다.

버전 3.5에서 변경: 윈도우 지원이 추가되었습니다.

socket.create_connection(address, timeout=GLOBAL_DEFAULT, source_address=None, *, all_errors=False)

Connect to a TCP service listening on the internet address (a 2-tuple (host, port)), and return the socket object. This is a higher-level function than socket.connect(): if host is a non-numeric hostname, it will try to resolve it for both AF_INET and AF_INET6, and then try to connect to all possible addresses in turn until a connection succeeds. This makes it easy to write clients that are compatible to both IPv4 and IPv6.

선택적 timeout 매개 변수를 전달하면 연결을 시도하기 전에 소켓 인스턴스의 시간제한을 설정합니다. timeout이 제공되지 않으면, getdefaulttimeout()에 의해 반환된 전역 기본 시간제한 설정이 사용됩니다.

제공되면, source_address는 연결하기 전에 소켓이 소스 주소로 바인드 할 2-튜플 (host, port) 여야 합니다. 호스트나 포트가 각각 ‘’ 나 0이면 OS 기본 동작이 사용됩니다.

When a connection cannot be created, an exception is raised. By default, it is the exception from the last address in the list. If all_errors is True, it is an ExceptionGroup containing the errors of all attempts.

버전 3.2에서 변경: source_address가 추가되었습니다.

버전 3.11에서 변경: all_errors was added.

socket.create_server(address, *, family=AF_INET, backlog=None, reuse_port=False, dualstack_ipv6=False)

Convenience function which creates a TCP socket bound to address (a 2-tuple (host, port)) and returns the socket object.

family should be either AF_INET or AF_INET6. backlog is the queue size passed to socket.listen(); if not specified , a default reasonable value is chosen. reuse_port dictates whether to set the SO_REUSEPORT socket option.

dualstack_ipv6가 참이고 플랫폼이 이를 지원하면, 소켓은 IPv4와 IPv6 연결을 모두 받아들일 수 있습니다, 그렇지 않으면 ValueError가 발생합니다. 대부분의 POSIX 플랫폼과 윈도우는 이 기능을 지원한다고 여겨집니다. 이 기능이 활성화되면, IPv4 연결이 이루어질 때 socket.getpeername()이 반환하는 주소는 IPv4-매핑된 IPv6 주소로 표현된 IPv6 주소가 됩니다. dualstack_ipv6가 거짓이면, 기본적으로 이 기능을 활성화하는 플랫폼에서 (예를 들어, 리눅스), 이 기능을 명시적으로 비활성화합니다. 이 매개 변수는 has_dualstack_ipv6()와 함께 사용할 수 있습니다:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)

참고

POSIX 플랫폼에서 SO_REUSEADDR 소켓 옵션은 같은 address에 바인드 되었고 TIME_WAIT 상태로 남아 있던 이전 소켓을 즉시 재사용하기 위해 설정됩니다.

Added in version 3.8.

socket.has_dualstack_ipv6()

플랫폼이 IPv4와 IPv6 연결을 모두 처리할 수 있는 TCP 소켓을 만드는 것을 지원하면 True를 반환합니다.

Added in version 3.8.

socket.fromfd(fd, family, type, proto=0)

Duplicate the file descriptor fd (an integer as returned by a file object’s fileno() method) and build a socket object from the result. Address family, socket type and protocol number are as for the socket() function above. The file descriptor should refer to a socket, but this is not checked — subsequent operations on the object may fail if the file descriptor is invalid. This function is rarely needed, but can be used to get or set socket options on a socket passed to a program as standard input or output (such as a server started by the Unix inet daemon). The socket is assumed to be in blocking mode.

새로 만들어진 소켓은 상속 불가능합니다.

버전 3.4에서 변경: 반환된 소켓은 이제 상속 불가능합니다.

socket.fromshare(data)

socket.share() 메서드에서 얻은 데이터로 소켓의 인스턴스를 만듭니다. 소켓은 블로킹 모드로 간주합니다.

Availability: Windows.

Added in version 3.3.

socket.SocketType

이것은 소켓 객체 형을 나타내는 파이썬 형 객체입니다. type(socket(...))과 같습니다.

기타 함수

socket 모듈은 또한 다양한 네트워크 관련 서비스를 제공합니다:

socket.close(fd)

소켓 파일 기술자를 닫습니다. 이것은 os.close()와 비슷하지만, 소켓 용입니다. 일부 플랫폼(가장 눈에 띄는 것은 윈도우)에서는 os.close()가 소켓 파일 기술자에 대해 작동하지 않습니다.

Added in version 3.7.

socket.getaddrinfo(host, port, family=AF_UNSPEC, type=0, proto=0, flags=0)

This function wraps the C function getaddrinfo of the underlying system.

host/port 인자를 해당 서비스에 연결된 소켓을 만드는 데 필요한 모든 인자가 들어있는 5-튜플의 시퀀스로 변환합니다. host는 도메인 이름, IPv4/v6 주소의 문자열 표현 또는 None입니다. port는 'http'와 같은 문자열 서비스 이름, 숫자 포트 번호 또는 None입니다. None을 host 와 port의 값으로 전달해서, NULL을 하부 C API에 전달할 수 있습니다.

The family, type and proto arguments can be optionally specified in order to provide options and limit the list of addresses returned. Pass their default values (AF_UNSPEC, 0, and 0, respectively) to not limit the results. See the note below for details.

The flags argument can be one or several of the AI_* constants, and will influence how results are computed and returned. For example, AI_NUMERICHOST will disable domain name resolution and will raise an error if host is a domain name.

이 함수는 다음과 같은 구조의 5-튜플의 리스트를 반환합니다:

(family, type, proto, canonname, sockaddr)

In these tuples, family, type, proto are all integers and are meant to be passed to the socket() function. canonname will be a string representing the canonical name of the host if AI_CANONNAME is part of the flags argument; else canonname will be empty. sockaddr is a tuple describing a socket address, whose format depends on the returned family (a (address, port) 2-tuple for AF_INET, a (address, port, flowinfo, scope_id) 4-tuple for AF_INET6), and is meant to be passed to the socket.connect() method.

참고

If you intend to use results from getaddrinfo() to create a socket (rather than, for example, retrieve canonname), consider limiting the results by type (e.g. SOCK_STREAM or SOCK_DGRAM) and/or proto (e.g. IPPROTO_TCP or IPPROTO_UDP) that your application can handle.

The behavior with default values of family, type, proto and flags is system-specific.

Many systems (for example, most Linux configurations) will return a sorted list of all matching addresses. These addresses should generally be tried in order until a connection succeeds (possibly tried in parallel, for example, using a Happy Eyeballs [https://en.wikipedia.org/wiki/Happy_Eyeballs] algorithm). In these cases, limiting the type and/or proto can help eliminate unsuccessful or unusable connection attempts.

Some systems will, however, only return a single address. (For example, this was reported on Solaris and AIX configurations.) On these systems, limiting the type and/or proto helps ensure that this address is usable.

host, port, family, type, protocol을 인자로 감사 이벤트(auditing event) socket.getaddrinfo를 발생시킵니다.

다음 예제는 example.org의 포트 80으로 가는 가상의 TCP 연결에 대한 주소 정보를 가져옵니다 (IPv6가 활성화되지 않았으면 여러분의 시스템에서는 결과가 다를 수 있습니다):

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]

버전 3.2에서 변경: 매개 변수는 이제 키워드 인자를 사용하여 전달할 수 있습니다.

버전 3.7에서 변경: IPv6 멀티캐스트 주소의 경우, 주소를 나타내는 문자열에는 %scope_id 부분이 포함되지 않습니다.

socket.getfqdn([name])

Return a fully qualified domain name for name. If name is omitted or empty, it is interpreted as the local host. To find the fully qualified name, the hostname returned by gethostbyaddr() is checked, followed by aliases for the host, if available. The first name which includes a period is selected. In case no fully qualified domain name is available and name was provided, it is returned unchanged. If name was empty or equal to '0.0.0.0', the hostname from gethostname() is returned.

socket.gethostbyname(hostname)

호스트 이름을 IPv4 주소 형식으로 변환합니다. IPv4 주소는 '100.50.200.5'와 같은 문자열로 반환됩니다. 호스트 이름이 IPv4 주소면 변경되지 않고 반환됩니다. 더욱 완전한 인터페이스는 gethostbyname_ex()를 참조하십시오. gethostbyname()는 IPv6 이름 결정을 지원하지 않으며, IPv4/v6 이중 스택 지원을 위해서는 대신 getaddrinfo()를 사용해야 합니다.

hostname을 인자로 감사 이벤트(auditing event) socket.gethostbyname을 발생시킵니다.

Availability: not WASI.

socket.gethostbyname_ex(hostname)

Translate a host name to IPv4 address format, extended interface. Return a 3-tuple (hostname, aliaslist, ipaddrlist) where hostname is the host’s primary host name, aliaslist is a (possibly empty) list of alternative host names for the same address, and ipaddrlist is a list of IPv4 addresses for the same interface on the same host (often but not always a single address). gethostbyname_ex() does not support IPv6 name resolution, and getaddrinfo() should be used instead for IPv4/v6 dual stack support.

hostname을 인자로 감사 이벤트(auditing event) socket.gethostbyname을 발생시킵니다.

Availability: not WASI.

socket.gethostname()

파이썬 인터프리터가 현재 실행 중인 기계의 호스트 명을 포함한 문자열을 반환합니다.

인자 없이 감사 이벤트(auditing event) socket.gethostname을 발생시킵니다.

참고: gethostname()은 항상 완전히 정규화된 도메인 이름을 반환하지는 않습니다; 원한다면 getfqdn()을 사용하십시오.

Availability: not WASI.

socket.gethostbyaddr(ip_address)

Return a 3-tuple (hostname, aliaslist, ipaddrlist) where hostname is the primary host name responding to the given ip_address, aliaslist is a (possibly empty) list of alternative host names for the same address, and ipaddrlist is a list of IPv4/v6 addresses for the same interface on the same host (most likely containing only a single address). To find the fully qualified domain name, use the function getfqdn(). gethostbyaddr() supports both IPv4 and IPv6.

ip_address를 인자로 감사 이벤트(auditing event) socket.gethostbyaddr을 발생시킵니다.

Availability: not WASI.

socket.getnameinfo(sockaddr, flags)

Translate a socket address sockaddr into a 2-tuple (host, port). Depending on the settings of flags, the result can contain a fully qualified domain name or numeric address representation in host. Similarly, port can contain a string port name or a numeric port number.

IPv6 주소의 경우, sockaddr에 의미 있는 scope_id가 있으면 %scope_id를 host 부분에 덧붙입니다. 보통 이것은 멀티캐스트 주소에서 일어납니다.

flags에 대한 자세한 내용은 getnameinfo(3) [https://manpages.debian.org/getnameinfo(3)]을 참조하십시오.

sockaddr을 인자로 감사 이벤트(auditing event) socket.getnameinfo를 발생시킵니다.

Availability: not WASI.

socket.getprotobyname(protocolname)

Translate an internet protocol name (for example, 'icmp') to a constant suitable for passing as the (optional) third argument to the socket() function. This is usually only needed for sockets opened in “raw” mode (SOCK_RAW); for the normal socket modes, the correct protocol is chosen automatically if the protocol is omitted or zero.

Availability: not WASI.

socket.getservbyname(servicename[, protocolname])

Translate an internet service name and protocol name to a port number for that service. The optional protocol name, if given, should be 'tcp' or 'udp', otherwise any protocol will match.

servicename, protocolname을 인자로 감사 이벤트(auditing event) socket.getservbyname을 발생시킵니다.

Availability: not WASI.

socket.getservbyport(port[, protocolname])

Translate an internet port number and protocol name to a service name for that service. The optional protocol name, if given, should be 'tcp' or 'udp', otherwise any protocol will match.

port, protocolname을 인자로 감사 이벤트(auditing event) socket.getservbyport를 발생시킵니다.

Availability: not WASI.

socket.ntohl(x)

32비트 양의 정수를 네트워크 바이트 순서에서 호스트 바이트 순서로 변환합니다. 호스트 바이트 순서가 네트워크 바이트 순서와 같은 시스템에서, 이것은 아무 일도 하지 않습니다; 그렇지 않으면, 4바이트 스와프 연산을 수행합니다.

socket.ntohs(x)

16비트 양의 정수를 네트워크 바이트 순서에서 호스트 바이트 순서로 변환합니다. 호스트 바이트 순서가 네트워크 바이트 순서와 같은 시스템에서, 이것은 아무 일도 하지 않습니다; 그렇지 않으면, 2바이트 스와프 연산을 수행합니다.

버전 3.10에서 변경: Raises OverflowError if x does not fit in a 16-bit unsigned integer.

socket.htonl(x)

32비트 양의 정수를 호스트 바이트 순서에서 네트워크 바이트 순서로 변환합니다. 호스트 바이트 순서가 네트워크 바이트 순서와 같은 시스템에서, 이것은 아무 일도 하지 않습니다; 그렇지 않으면, 4바이트 스와프 연산을 수행합니다.

socket.htons(x)

16비트 양의 정수를 호스트 바이트 순서에서 네트워크 바이트 순서로 변환합니다. 호스트 바이트 순서가 네트워크 바이트 순서와 같은 시스템에서, 이것은 아무 일도 하지 않습니다; 그렇지 않으면, 2바이트 스와프 연산을 수행합니다.

버전 3.10에서 변경: Raises OverflowError if x does not fit in a 16-bit unsigned integer.

socket.inet_aton(ip_string)

Convert an IPv4 address from dotted-quad string format (for example, ‘123.45.67.89’) to 32-bit packed binary format, as a bytes object four characters in length. This is useful when conversing with a program that uses the standard C library and needs objects of type in_addr, which is the C type for the 32-bit packed binary this function returns.

inet_aton()는 3점 미만의 문자열도 허용합니다; 자세한 내용은 유닉스 매뉴얼 페이지 inet(3) [https://manpages.debian.org/inet(3)]을 참조하십시오.

이 함수에 전달된 IPv4 주소 문자열이 유효하지 않으면, OSError가 발생합니다. 정확히 무엇이 유효한지는 inet_aton()의 하부 C 구현에 따라 달라짐에 유의하십시오.

inet_aton()은 IPv6를 지원하지 않으며, IPv4/v6 이중 스택 지원을 위해서는 대신 inet_pton()를 사용해야 합니다.

socket.inet_ntoa(packed_ip)

Convert a 32-bit packed IPv4 address (a bytes-like object four bytes in length) to its standard dotted-quad string representation (for example, ‘123.45.67.89’). This is useful when conversing with a program that uses the standard C library and needs objects of type in_addr, which is the C type for the 32-bit packed binary data this function takes as an argument.

이 함수에 전달된 바이트 시퀀스가 정확히 4바이트 길이가 아니면, OSError가 발생합니다. inet_ntoa()는 IPv6를 지원하지 않으며, IPv4/v6 이중 스택 지원을 위해서는 대신 inet_ntop()를 사용해야 합니다.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

socket.inet_pton(address_family, ip_string)

Convert an IP address from its family-specific string format to a packed, binary format. inet_pton() is useful when a library or network protocol calls for an object of type in_addr (similar to inet_aton()) or in6_addr.

address_family에 대해 지원되는 값은 현재 AF_INET과 AF_INET6입니다. IP 주소 문자열 ip_string가 유효하지 않으면, OSError가 발생합니다. 정확히 무엇이 유효한지는 address_family의 값과 inet_pton()의 하부 구현에 따라 달라집니다.

Availability: Unix, Windows.

버전 3.4에서 변경: 윈도우 지원이 추가되었습니다

socket.inet_ntop(address_family, packed_ip)

Convert a packed IP address (a bytes-like object of some number of bytes) to its standard, family-specific string representation (for example, '7.10.0.5' or '5aef:2b::8'). inet_ntop() is useful when a library or network protocol returns an object of type in_addr (similar to inet_ntoa()) or in6_addr.

address_family에 대해 지원되는 값은 현재 AF_INET과 AF_INET6입니다. 바이트열 객체 packed_ip가 지정된 주소 패밀리의 올바른 길이가 아니면, ValueError가 발생합니다. inet_ntop() 호출로 인한 에러에는 OSError가 발생합니다.

Availability: Unix, Windows.

버전 3.4에서 변경: 윈도우 지원이 추가되었습니다

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

socket.CMSG_LEN(length)

주어진 length의 연관된 데이터가 있는 보조(ancillary) 데이터 항목의 (후행 패딩을 제외한) 총 길이를 반환합니다. 이 값은 recvmsg()가 보조 데이터의 단일 항목을 수신하기 위한 버퍼 크기로 종종 사용될 수 있지만, RFC 3542 [https://datatracker.ietf.org/doc/html/rfc3542.html]는 이식성 있는 응용 프로그램에서 CMSG_SPACE()를 사용하도록 요구하는데, 항목이 버퍼의 마지막 부분일 때도 패딩을 위한 공간을 포함합니다. length가 허용되는 값 범위를 벗어나면 OverflowError를 발생시킵니다.

Availability: Unix, not WASI.

Most Unix platforms.

Added in version 3.3.

socket.CMSG_SPACE(length)

주어진 length의 연관된 데이터가 있는 보조(ancillary) 데이터 항목을 수신하기 위해 recvmsg()에 필요한 버퍼 크기를 반환하는데, 후행 패딩을 포함합니다. 여러 항목을 수신하는 데 필요한 버퍼 공간은 연관된 데이터 길이에 대한 CMSG_SPACE() 값의 합입니다. length가 허용되는 값 범위를 벗어나면 OverflowError를 발생시킵니다.

일부 시스템에서는 이 함수를 제공하지 않으면서 보조(ancillary) 데이터를 지원할 수 있음에 유의하십시오. 또한, 이 함수의 결과를 사용하여 버퍼 크기를 설정하면 수신할 수 있는 보조 데이터의 양이 정확하게 제한되지 않을 수 있음에도 유의하십시오. 추가 데이터가 패딩 영역에 들어갈 수 있기 때문입니다.

Availability: Unix, not WASI.

most Unix platforms.

Added in version 3.3.

socket.getdefaulttimeout()

새로운 소켓 객체의 기본 시간제한을 초 단위로 (float) 반환합니다. None 값은 새 소켓 객체가 시간제한이 없음을 나타냅니다. 소켓 모듈을 처음 임포트 할 때 기본값은 None입니다.

socket.setdefaulttimeout(timeout)

새 소켓 객체의 기본 시간제한을 초 단위로 (float) 설정합니다. 소켓 모듈을 처음 임포트 할 때 기본값은 None입니다. 가능한 값과 해당 의미는 settimeout()을 참조하십시오.

socket.sethostname(name)

기계의 호스트 명을 name으로 설정합니다. 충분한 권한이 없으면 OSError가 발생합니다.

name을 인자로 감사 이벤트(auditing event) socket.sethostname을 발생시킵니다.

Availability: Unix, not Android.

Added in version 3.3.

socket.if_nameindex()

네트워크 인터페이스 정보 (인덱스 정수, 이름 문자열) 튜플의 리스트를 반환합니다. 시스템 호출이 실패하면 OSError.

Availability: Unix, Windows, not WASI.

Added in version 3.3.

버전 3.8에서 변경: 윈도우 지원이 추가되었습니다.

참고

윈도우에서 네트워크 인터페이스는 다른 문맥에서 다른 이름을 갖습니다 (모든 이름은 예입니다):

UUID: {FB605B73-AAC2-49A6-9A2F-25416AEA0573}

이름: ethernet_32770

친숙한 이름: vEthernet (nat)

설명: Hyper-V Virtual Ethernet Adapter

이 함수는 목록에서 두 번째 형식의 이름을 반환합니다, 이 예의 경우 ethernet_32770.

socket.if_nametoindex(if_name)

인터페이스 이름에 대응하는 네트워크 인터페이스 인덱스 번호를 반환합니다. 주어진 이름을 가진 인터페이스가 없으면 OSError.

Availability: Unix, Windows, not WASI.

Added in version 3.3.

버전 3.8에서 변경: 윈도우 지원이 추가되었습니다.

더 보기

“인터페이스 이름”은 if_nameindex()에 설명된 이름입니다.

socket.if_indextoname(if_index)

인터페이스 인덱스 번호에 해당하는 네트워크 인터페이스 이름을 반환합니다. 지정된 인덱스의 인터페이스가 없으면 OSError.

Availability: Unix, Windows, not WASI.

Added in version 3.3.

버전 3.8에서 변경: 윈도우 지원이 추가되었습니다.

더 보기

“인터페이스 이름”은 if_nameindex()에 설명된 이름입니다.

socket.send_fds(sock, buffers, fds[, flags[, address]])

Send the list of file descriptors fds over an AF_UNIX socket sock. The fds parameter is a sequence of file descriptors. Consult sendmsg() for the documentation of these parameters.

Availability: Unix, Windows, not WASI.

Unix platforms supporting sendmsg() and SCM_RIGHTS mechanism.

Added in version 3.9.

socket.recv_fds(sock, bufsize, maxfds[, flags])

Receive up to maxfds file descriptors from an AF_UNIX socket sock. Return (msg, list(fds), flags, addr). Consult recvmsg() for the documentation of these parameters.

Availability: Unix, Windows, not WASI.

Unix platforms supporting sendmsg() and SCM_RIGHTS mechanism.

Added in version 3.9.

참고

파일 기술자 리스트 끝에 있는 모든 잘린 정수.

소켓 객체

소켓 객체에는 다음과 같은 메서드가 있습니다. makefile()를 제외하고, 이것들은 소켓에 적용할 수 있는 유닉스 시스템 호출에 해당합니다.

버전 3.2에서 변경: 컨텍스트 관리자 프로토콜 지원이 추가되었습니다. 컨텍스트 관리자를 빠져나가는 것은 close()를 호출하는 것과 동등합니다.

socket.accept()

연결을 받아들입니다. 소켓은 주소에 바인드되어 연결을 리스닝하고 있어야 합니다. 반환 값은 (conn, address) 쌍입니다. 여기서 conn는 연결에서 데이터를 보내고 받을 수 있는 새로운 소켓 객체이고, address는 연결의 다른 끝에 있는 소켓에 바인드 된 주소입니다.

새로 만들어진 소켓은 상속 불가능합니다.

버전 3.4에서 변경: 소켓은 이제 상속 불가능합니다.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.bind(address)

소켓을 address에 바인드 합니다. 소켓은 이미 바인드 되어 있으면 안 됩니다. (address의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

self, address을 인자로 감사 이벤트(auditing event) socket.bind를 발생시킵니다.

Availability: not WASI.

socket.close()

Mark the socket closed. The underlying system resource (e.g. a file descriptor) is also closed when all file objects from makefile() are closed. Once that happens, all future operations on the socket object will fail. The remote end will receive no more data (after queued data is flushed).

소켓은 가비지 수집될 때 자동으로 닫히지만, 명시적으로 close()하거나 with 문을 사용하는 것이 좋습니다.

버전 3.6에서 변경: 하부 close() 호출이 수행될 때 에러가 발생하면 이제 OSError가 발생합니다.

참고

close() releases the resource associated with a connection but does not necessarily close the connection immediately. If you want to close the connection in a timely fashion, call shutdown() before close().

socket.connect(address)

address에 있는 원격 소켓에 연결합니다. (address의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

If the connection is interrupted by a signal, the method waits until the connection completes, or raise a TimeoutError on timeout, if the signal handler doesn’t raise an exception and the socket is blocking or has a timeout. For non-blocking sockets, the method raises an InterruptedError exception if the connection is interrupted by a signal (or the exception raised by the signal handler).

self, address를 인자로 감사 이벤트(auditing event) socket.connect를 발생시킵니다.

버전 3.5에서 변경: 연결이 시그널에 의해 인터럽트 되고, 시그널 처리기가 예외를 발생시키지 않고, 소켓이 블로킹하거나 시간제한을 가지면, 이 메서드는 이제 InterruptedError 예외를 발생시키는 대신 연결이 완료될 때까지 대기합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

Availability: not WASI.

socket.connect_ex(address)

connect(address)와 비슷하지만, C 수준의 connect() 호출로 반환된 에러에 대한 예외를 발생시키는 대신 에러 표시기를 반환합니다 (“호스트를 찾을 수 없음”과 같은 다른 문제는 여전히 예외를 발생시킬 수 있습니다). 연산이 성공하면 에러 표시기는 0이고, 그렇지 않으면 errno 변수의 값입니다. 예를 들어 비동기 연결을 지원하는 데 유용합니다.

self, address를 인자로 감사 이벤트(auditing event) socket.connect를 발생시킵니다.

Availability: not WASI.

socket.detach()

하부 파일 기술자를 실제로 닫지 않으면서 소켓 객체를 닫힌 상태로 만듭니다. 파일 기술자가 반환되고, 다른 용도로 재사용 될 수 있습니다.

Added in version 3.2.

socket.dup()

소켓을 복제합니다.

새로 만들어진 소켓은 상속 불가능합니다.

버전 3.4에서 변경: 소켓은 이제 상속 불가능합니다.

Availability: not WASI.

socket.fileno()

소켓의 파일 기술자(작은 정수)를 반환하거나, 실패하면 -1을 반환합니다. 이것은 select.select()에서 유용합니다.

윈도우에서, 이 메서드가 돌려주는 작은 정수는 파일 기술자를 사용할 수 있는 곳(가령 os.fdopen())에 사용할 수 없습니다. 유닉스에는 이러한 제한이 없습니다.

socket.get_inheritable()

소켓의 파일 기술자나 소켓 핸들의 상속 가능 플래그를 가져옵니다: 소켓이 자식 프로세스에서 상속될 수 있으면 True, 그렇지 않으면 False.

Added in version 3.4.

socket.getpeername()

소켓이 연결된 원격 주소를 반환합니다. 이것은 예를 들어, 원격 IPv4/v6 소켓의 포트 번호를 찾는 데 유용합니다. (반환되는 주소의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.) 일부 시스템에서는 이 함수가 지원되지 않습니다.

socket.getsockname()

소켓 자신의 주소를 반환합니다. 이것은 예를 들어 IPv4/v6 소켓의 포트 번호를 찾는 데 유용합니다. (반환되는 주소의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

socket.getsockopt(level, optname[, buflen])

Return the value of the given socket option (see the Unix man page getsockopt(2) [https://manpages.debian.org/getsockopt(2)]). The needed symbolic constants (SO_* etc.) are defined in this module. If buflen is absent, an integer option is assumed and its integer value is returned by the function. If buflen is present, it specifies the maximum length of the buffer used to receive the option in, and this buffer is returned as a bytes object. It is up to the caller to decode the contents of the buffer (see the optional built-in module struct for a way to decode C structures encoded as byte strings).

Availability: not WASI.

socket.getblocking()

소켓이 블로킹 모드면 True를 반환하고, 비 블로킹이면 False를 반환합니다.

This is equivalent to checking socket.gettimeout() != 0.

Added in version 3.7.

socket.gettimeout()

소켓 연산에 관련한 시간제한을 초(float)로 돌려줍니다. 시간제한이 설정되어 있지 않으면 None를 돌려줍니다. 이것은 setblocking() 이나 settimeout()에 대한 마지막 호출을 반영합니다.

socket.ioctl(control, option)

ioctl() 메서드는 WSAIoctl 시스템 인터페이스에 대한 제한된 인터페이스입니다. 자세한 내용은 Win32 설명서 [https://msdn.microsoft.com/en-us/library/ms741621%28VS.85%29.aspx]를 참조하십시오.

다른 플랫폼에서는, 범용 fcntl.fcntl() 과 fcntl.ioctl() 함수를 사용할 수 있습니다; 첫 번째 인자로 소켓 객체를 받아들입니다.

현재 다음 제어 코드만 지원됩니다: SIO_RCVALL, SIO_KEEPALIVE_VALS 및 SIO_LOOPBACK_FAST_PATH.

Availability: Windows

버전 3.6에서 변경: SIO_LOOPBACK_FAST_PATH가 추가되었습니다.

socket.listen([backlog])

서버가 연결을 수락하도록 합니다. backlog가 지정되면, 0 이상이어야 합니다 (더 낮으면 0으로 설정됩니다); 새로운 연결을 거부하기 전에 시스템이 허락할 수락되지 않은 연결 수를 지정합니다. 지정하지 않으면, 기본값으로 적당한 값이 선택됩니다.

Availability: not WASI.

버전 3.5에서 변경: 이제 backlog 매개 변수가 선택적입니다.

socket.makefile(mode='r', buffering=None, *, encoding=None, errors=None, newline=None)

Return a file object associated with the socket. The exact returned type depends on the arguments given to makefile(). These arguments are interpreted the same way as by the built-in open() function, except the only supported mode values are 'r' (default), 'w', 'b', or a combination of those.

소켓은 블로킹 모드 여야 합니다; 시간제한을 가질 수 있지만, 시간 초과가 발생하면 파일 객체의 내부 버퍼가 일관성없는 상태로 끝날 수 있습니다.

makefile()에 의해 반환된 파일 객체를 닫는 것은, 다른 모든 파일 객체가 닫혔고 소켓 객체에서 socket.close()가 호출되었지 않은 한 원래 소켓을 닫지는 않습니다.

참고

윈도우에서, makefile()로 만든 파일류 객체는 파일 기술자가 있는 파일 객체가 필요한 곳에서는 사용할 수 없습니다, 가령 subprocess.Popen()의 stream 인자.

socket.recv(bufsize[, flags])

Receive data from the socket. The return value is a bytes object representing the data received. The maximum amount of data to be received at once is specified by bufsize. A returned empty bytes object indicates that the client has disconnected. See the Unix manual page recv(2) [https://manpages.debian.org/recv(2)] for the meaning of the optional argument flags; it defaults to zero.

참고

하드웨어와 네트워크 현실과 가장 잘 일치하려면, bufsize의 값은 2의 비교적 작은 거듭제곱이어야 합니다, 예를 들어 4096.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.recvfrom(bufsize[, flags])

소켓에서 데이터를 수신합니다. 반환 값은 (bytes, address) 쌍입니다. 여기서 bytes는 수신한 데이터를 나타내는 바이트열 객체이고, address는 데이터를 보내는 소켓의 주소입니다. 선택적 인자 flags의 의미는 유닉스 매뉴얼 페이지 recv(2) [https://manpages.debian.org/recv(2)]를 보십시오; 기본값은 0입니다. (address의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

버전 3.7에서 변경: 멀티캐스트 IPv6 주소의 경우, address의 첫 번째 항목에는 %scope_id 부분이 더는 포함되지 않습니다. 전체 IPv6 주소를 얻으려면 getnameinfo()를 사용하십시오.

socket.recvmsg(bufsize[, ancbufsize[, flags]])

일반 데이터(최대 bufsize 바이트)와 보조(ancillary) 데이터를 소켓에서 수신합니다. ancbufsize 인자는 보조 데이터 수신에 사용되는 내부 버퍼의 크기를 바이트 단위로 설정합니다; 기본값은 0이며 보조 데이터가 수신되지 않는다는 뜻입니다. 보조 데이터를 위한 적절한 버퍼 크기는 CMSG_SPACE() 나 CMSG_LEN()를 사용하여 계산할 수 있으며, 버퍼에 들어가지 않는 항목은 잘리거나 삭제될 수 있습니다. flags 인자의 기본값은 0이고 recv()와 같은 의미입니다.

반환 값은 4-튜플입니다: (data, ancdata, msg_flags, address). data 항목은 일반 데이터를 담은 bytes 객체입니다. ancdata 항목은 수신된 보조 데이터(제어 메시지)를 나타내는 0개 이상의 튜플 (cmsg_level, cmsg_type, cmsg_data)의 리스트입니다: cmsg_level 와 cmsg_type는 각각 프로토콜 수준과 프로토콜 특정 형을 지정하는 정수이고, cmsg_data는 연결된 데이터를 담은 bytes 객체입니다. msg_flags 항목은 수신된 메시지의 조건을 나타내는 다양한 플래그의 비트별 OR입니다; 자세한 내용은 시스템 설명서를 참조하십시오. 수신 소켓이 연결되어있지 않으면, address는 송신 소켓의 주소입니다, (사용 가능하다면); 그렇지 않으면 값은 지정되지 않습니다.

On some systems, sendmsg() and recvmsg() can be used to pass file descriptors between processes over an AF_UNIX socket. When this facility is used (it is often restricted to SOCK_STREAM sockets), recvmsg() will return, in its ancillary data, items of the form (socket.SOL_SOCKET, socket.SCM_RIGHTS, fds), where fds is a bytes object representing the new file descriptors as a binary array of the native C int type. If recvmsg() raises an exception after the system call returns, it will first attempt to close any file descriptors received via this mechanism.

일부 시스템은 부분적으로만 수신된 보조 데이터 항목의 절단 길이를 나타내지 않습니다. 항목이 버퍼의 끝을 넘어 확장된 것처럼 보이면, recvmsg()는 RuntimeWarning를 발생시키고, 관련 데이터의 시작 전에 절단되지 않은 버퍼 내에 있는 부분을 반환합니다.

SCM_RIGHTS 메커니즘을 지원하는 시스템에서, 다음 함수는 최대 maxfds 파일 기술자를 수신하여, 메시지 데이터와 기술자를 담은 리스트를 반환합니다 (관련 없는 수신되는 제어 메시지와 같은 예기치 않은 조건은 무시하면서). sendmsg()를 참조하십시오.

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)

Availability: Unix.

Most Unix platforms.

Added in version 3.3.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.recvmsg_into(buffers[, ancbufsize[, flags]])

recvmsg()처럼 동작해서, 일반 데이터와 보조 데이터를 소켓에서 수신하지만, 새로운 바이트열 객체를 반환하는 대신 일반 데이터를 일련의 버퍼로 분산시킵니다. buffers 인자는 쓰기 가능한 버퍼(예를 들어, bytearray 객체)를 내보내는 객체의 이터러블이어야 합니다; 이것들은 모두 기록되었거나 버퍼가 더는 없을 때까지 일반 데이터의 연속적인 덩어리로 채워질 것입니다. 운영 체제는 사용할 수 있는 버퍼 수에 제한(sysconf() 값 SC_IOV_MAX)을 설정할 수 있습니다. ancbufsize 와 flags 인자는 recvmsg()와 같은 의미가 있습니다.

반환 값은 4-튜플입니다: (nbytes, ancdata, msg_flags, address). 여기서 nbytes는 버퍼에 기록된 일반 데이터의 총 바이트 수이며, ancdata, msg_flags 및 address는 recvmsg()와 같습니다.

예제:

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]

Availability: Unix.

Most Unix platforms.

Added in version 3.3.

socket.recvfrom_into(buffer[, nbytes[, flags]])

소켓에서 데이터를 수신하는데, 새로운 바이트열을 만드는 대신 buffer에 씁니다. 반환 값은 쌍 (nbytes, address)입니다. 여기서 nbytes는 수신 된 바이트 수이고, address는 데이터를 보내는 소켓의 주소입니다. 선택적 인자 flags의 의미에 대해서는 유닉스 매뉴얼 페이지 recv(2) [https://manpages.debian.org/recv(2)]를 보십시오; 기본값은 0입니다. (address의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

socket.recv_into(buffer[, nbytes[, flags]])

소켓에서 최대 nbytes 바이트까지 수신하는데, 새 바이트열을 만드는 대신 데이터를 버퍼에 저장합니다. nbytes가 지정되지 않으면 (또는 0), 지정된 버퍼에서 사용 가능한 크기까지 수신합니다. 수신 한 바이트 수를 반환합니다. 선택적 인자 flags의 의미에 대해서는 유닉스 매뉴얼 페이지 recv(2) [https://manpages.debian.org/recv(2)]를 보십시오; 기본값은 0입니다.

socket.send(bytes[, flags])

소켓에 데이터를 보냅니다. 소켓은 원격 소켓에 연결되어야 합니다. 선택적 flags 인자는 위의 recv()와 같은 의미입니다. 전송된 바이트 수를 반환합니다. 응용 프로그램은 모든 데이터가 전송되었는지 확인해야 합니다; 일부 데이터만 전송되었으면, 응용 프로그램은 나머지 데이터의 전달을 시도해야 합니다. 이 주제에 대한 자세한 정보는, 소켓 프로그래밍 HOWTO를 참조하십시오.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.sendall(bytes[, flags])

소켓에 데이터를 보냅니다. 소켓은 원격 소켓에 연결되어야 합니다. 선택적 flags 인자는 위의 recv()와 같은 의미입니다. send()와 달리, 이 메서드는 모든 데이터가 전송되거나 에러가 발생할 때까지 bytes의 데이터를 계속 전송합니다. 성공하면 None이 반환됩니다. 에러가 발생하면, 예외가 발생하는데, 성공적으로 전송된 데이터양을 (있기는 하다면) 확인하는 방법은 없습니다.

버전 3.5에서 변경: The socket timeout is no longer reset each time data is sent successfully. The socket timeout is now the maximum total duration to send all data.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.sendto(bytes, address)

socket.sendto(bytes, flags, address)

소켓에 데이터를 보냅니다. 대상 소켓이 address로 지정되므로, 소켓은 원격 소켓에 연결되지 않아야 합니다. 선택적 flags 인자는 위의 recv()와 같은 의미가 있습니다. 전송된 바이트 수를 반환합니다. (address의 형식은 주소 패밀리에 따라 다릅니다 — 위를 보십시오.)

self, address를 인자로 감사 이벤트(auditing event) socket.sendto를 발생시킵니다.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.sendmsg(buffers[, ancdata[, flags[, address]]])

소켓에 일반과 보조 데이터를 보는데, 일련의 버퍼에서 일반 데이터를 모아서 단일 메시지로 연결합니다. buffers 인자는 일반 데이터를 바이트열류 객체의 이터러블로 지정합니다 (예를 들어, bytes 객체); 운영 체제는 사용할 수 있는 버퍼 수에 제한(sysconf() 값 SC_IOV_MAX)을 설정할 수 있습니다. ancdata 인자는 보조 데이터 (제어 메시지)를 0개 이상의 튜플 (cmsg_level, cmsg_type, cmsg_data)의 이터러블로 지정합니다. 여기서 cmsg_level 와 cmsg_type는 각각 프로토콜 수준과 프로토콜 특정 형을 지정하는 정수이고, cmsg_data는 연결된 데이터를 담은 바이트열류 객체입니다. 일부 시스템(특히, CMSG_SPACE()가 없는 시스템)은 호출 당 하나의 제어 메시지를 송신하는 것만 지원할 수 있습니다. flags 인자의 기본값은 0이고 send()와 같은 의미입니다. address가 제공되고 None이 아니면, 메시지의 대상 주소를 설정합니다. 반환 값은 전송된 일반 데이터의 바이트 수입니다.

다음 함수는 SCM_RIGHTS 메커니즘을 지원하는 시스템에서, AF_UNIX 소켓을 통해 파일 기술자 리스트 fds를 보냅니다. recvmsg()도 참조하세요.

import socket, array

def send_fds(sock, msg, fds):
    return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])

Availability: Unix, not WASI.

Most Unix platforms.

self, address를 인자로 감사 이벤트(auditing event) socket.sendmsg를 발생시킵니다.

Added in version 3.3.

버전 3.5에서 변경: 시스템 호출이 인터럽트 되고 시그널 처리기가 예외를 발생시키지 않으면, 메서드는 이제 InterruptedError 예외를 발생시키는 대신 시스템 호출을 재시도합니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

socket.sendmsg_afalg([msg, ]*, op[, iv[, assoclen[, flags]]])

AF_ALG 소켓용, sendmsg()의 특수한 버전. AF_ALG 소켓에 대한 모드, IV, AEAD 관련 데이터 길이 및 플래그를 설정합니다.

Availability: Linux >= 2.6.38.

Added in version 3.6.

socket.sendfile(file, offset=0, count=None)

고성능 os.sendfile을 사용하여 EOF에 도달할 때까지 파일을 보내고, 보낸 총 바이트 수를 반환합니다. file은 바이너리 모드로 열린 일반 파일 객체여야 합니다. os.sendfile을 사용할 수 없거나 (예를 들어, 윈도우) file가 일반 파일이 아니면, send()가 대신 사용됩니다. offset은 파일 읽기 시작할 위치를 알려줍니다. 지정되면, count는 EOF에 도달할 때까지 파일을 전송하는 대신 전송할 총 바이트 수입니다. 파일 위치는 반환하거나 에러가 발생했을 때 갱신됩니다. 이때 file.tell()을 사용하여 전송된 바이트 수를 계산할 수 있습니다. 소켓은 SOCK_STREAM 유형이어야 합니다. 비 블로킹 소켓은 지원되지 않습니다.

Added in version 3.5.

socket.set_inheritable(inheritable)

소켓의 파일 기술자나 소켓 핸들의 상속 가능 플래그를 설정합니다.

Added in version 3.4.

socket.setblocking(flag)

소켓의 블로킹이나 비 블로킹 모드를 설정합니다. flag가 거짓이면, 소켓은 비 블로킹으로 설정되고, 그렇지 않으면 블로킹 모드로 설정됩니다.

이 메서드는 특정 settimeout() 호출의 줄인 표현입니다:

sock.setblocking(True)는 sock.settimeout(None)와 동등합니다

sock.setblocking(False)는 sock.settimeout(0.0)와 동등합니다

버전 3.7에서 변경: 이 메서드는 더는 socket.type에 SOCK_NONBLOCK 플래그를 적용하지 않습니다.

socket.settimeout(value)

Set a timeout on blocking socket operations. The value argument can be a nonnegative floating-point number expressing seconds, or None. If a non-zero value is given, subsequent socket operations will raise a timeout exception if the timeout period value has elapsed before the operation has completed. If zero is given, the socket is put in non-blocking mode. If None is given, the socket is put in blocking mode.

자세한 내용은, 소켓 시간제한에 대한 참고 사항을 보십시오.

버전 3.7에서 변경: 이 메서드는 더는 socket.type의 SOCK_NONBLOCK 플래그를 토글하지 않습니다.

socket.setsockopt(level, optname, value: int)

socket.setsockopt(level, optname, value: buffer)

socket.setsockopt(level, optname, None, optlen: int)

Set the value of the given socket option (see the Unix manual page setsockopt(2) [https://manpages.debian.org/setsockopt(2)]). The needed symbolic constants are defined in this module (SO_* etc. <socket-unix-constants>). The value can be an integer, None or a bytes-like object representing a buffer. In the later case it is up to the caller to ensure that the bytestring contains the proper bits (see the optional built-in module struct for a way to encode C structures as bytestrings). When value is set to None, optlen argument is required. It’s equivalent to call setsockopt() C function with optval=NULL and optlen=optlen.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

버전 3.6에서 변경: setsockopt(level, optname, None, optlen: int) 형식이 추가되었습니다.

Availability: not WASI.

socket.shutdown(how)

연결의 한쪽 또는 양쪽 절반을 닫습니다. how가 SHUT_RD면, 추가 수신이 허용되지 않습니다. how가 SHUT_WR이면, 추가 전송이 허용되지 않습니다. how가 SHUT_RDWR이면, 추가 송수신이 허용되지 않습니다.

Availability: not WASI.

socket.share(process_id)

소켓을 복제하고 대상 프로세스와 공유할 수 있도록 준비합니다. 대상 프로세스는 process_id로 제공되어야 합니다. 결과 바이트열 객체는 어떤 프로세스 간 통신의 형태를 사용하여 대상 프로세스로 전달될 수 있으며 그곳에서 fromshare()를 사용하여 소켓을 다시 만들 수 있습니다. 일단, 이 메서드가 호출되면, 운영 체제가 이미 대상 프로세스를 위해 이를 복제 했으므로 소켓을 닫아도 안전합니다.

Availability: Windows.

Added in version 3.3.

메서드 read() 나 write()가 없다는 점에 유의하십시오; 대신 recv() 와 send()를 flags 인자 없이 사용하십시오.

소켓 객체는 또한 socket 생성자에 지정된 값에 대응하는 다음과 같은 (읽기 전용) 어트리뷰트를 가집니다.

socket.family

소켓 패밀리.

socket.type

소켓 유형.

socket.proto

소켓 프로토콜.

소켓 시간제한에 대한 참고 사항

소켓 객체는 세 가지 모드 중 하나일 수 있습니다: 블로킹, 비 블로킹, 또는 시간제한. 소켓은 기본적으로 항상 블로킹 모드로 생성되지만, 이는 setdefaulttimeout()를 호출하여 변경할 수 있습니다.

블로킹 모드에서, 연산은 완료되거나 시스템에서 에러(가령 연결 시간 초과)를 반환할 때까지 블록합니다.

In non-blocking mode, operations fail (with an error that is unfortunately system-dependent) if they cannot be completed immediately: functions from the select module can be used to know when and whether a socket is available for reading or writing.

시간제한 모드에서, 연산은 소켓에 대해 지정된 제한 시간 내에 완료할 수 없거나 (timeout 예외 발생), 시스템이 에러를 반환하면 실패합니다.

참고

At the operating system level, sockets in timeout mode are internally set in non-blocking mode. Also, the blocking and timeout modes are shared between file descriptors and socket objects that refer to the same network endpoint. This implementation detail can have visible consequences if e.g. you decide to use the fileno() of a socket.

시간제한과 connect 메서드

connect() 연산도 시간제한 설정의 영향을 받으며, 일반적으로 connect()를 호출하기 전에 settimeout()를 호출하거나 create_connection()에 timeout 매개 변수를 전달하는 것이 좋습니다. 그러나, 시스템 네트워크 스택은 파이썬 소켓 시간제한 설정과 관계없이 자체의 연결 시간제한 에러를 반환할 수 있습니다.

시간제한과 accept 메서드

getdefaulttimeout()가 None이 아니면, accept() 메서드에서 반환된 소켓은 그 시간제한을 상속합니다. 그렇지 않으면, 동작은 리스닝 소켓의 설정에 따라 다릅니다:

리스닝 소켓이 블로킹 모드 나 시간제한 모드에 있으면, accept()에 의해 반환된 소켓은 블로킹 모드에 있습니다.

리스닝 소켓이 비 블로킹 모드에 있으면, accept()에 의해 반환된 소켓이 블로킹 모드인지 비 블로킹 모드인지는 운영 체제에 따라 다릅니다. 플랫폼 간 동작을 보장하려면, 이 설정을 직접 재정의하는 것이 좋습니다.

예제

Here are four minimal example programs using the TCP/IP protocol: a server that echoes all data that it receives back (servicing only one client), and a client using it. Note that a server must perform the sequence socket(), bind(), listen(), accept() (possibly repeating the accept() to service more than one client), while a client only needs the sequence socket(), connect(). Also note that the server does not sendall()/recv() on the socket it is listening on but on the new socket returned by accept().

처음 두 예제는 IPv4만 지원합니다.

# Echo server program
import socket

HOST = ''                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen(1)
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data: break
            conn.sendall(data)

# Echo client program
import socket

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))

The next two examples are identical to the above two, but support both IPv4 and IPv6. The server side will listen to the first address family available (it should listen to both instead). On most of IPv6-ready systems, IPv6 will take precedence and the server may not accept IPv4 traffic. The client side will try to connect to all the addresses returned as a result of the name resolution, and sends traffic to the first one connected successfully.

# Echo server program
import socket
import sys

HOST = None               # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                              socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except OSError as msg:
        s = None
        continue
    try:
        s.bind(sa)
        s.listen(1)
    except OSError as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print('could not open socket')
    sys.exit(1)
conn, addr = s.accept()
with conn:
    print('Connected by', addr)
    while True:
        data = conn.recv(1024)
        if not data: break
        conn.send(data)

# Echo client program
import socket
import sys

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except OSError as msg:
        s = None
        continue
    try:
        s.connect(sa)
    except OSError as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print('could not open socket')
    sys.exit(1)
with s:
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))

다음 예제는 윈도우에서 원시(raw) 소켓으로 매우 간단한 네트워크 스니퍼를 작성하는 방법을 보여줍니다. 이 예제는 인터페이스를 수정하기 위해 관리자 권한이 필요합니다:

import socket

# the public network interface
HOST = socket.gethostbyname(socket.gethostname())

# create a raw socket and bind it to the public interface
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_IP)
s.bind((HOST, 0))

# Include IP headers
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

# receive all packets
s.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)

# receive a packet
print(s.recvfrom(65565))

# disabled promiscuous mode
s.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)

다음 예제는 원시(raw) 소켓 프로토콜을 사용하여, 소켓 인터페이스를 사용하여 CAN 네트워크와 통신하는 방법을 보여줍니다. 대신 브로드캐스트 관리자 프로토콜로 CAN을 사용하려면, 소켓을 이렇게 여십시오:

socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_BCM)

After binding (CAN_RAW) or connecting (CAN_BCM) the socket, you can use the socket.send() and socket.recv() operations (and their counterparts) on the socket object as usual.

이 마지막 예제는 특별한 권한이 필요할 수 있습니다:

import socket
import struct

# CAN frame packing/unpacking (see 'struct can_frame' in <linux/can.h>)

can_frame_fmt = "=IB3x8s"
can_frame_size = struct.calcsize(can_frame_fmt)

def build_can_frame(can_id, data):
    can_dlc = len(data)
    data = data.ljust(8, b'\x00')
    return struct.pack(can_frame_fmt, can_id, can_dlc, data)

def dissect_can_frame(frame):
    can_id, can_dlc, data = struct.unpack(can_frame_fmt, frame)
    return (can_id, can_dlc, data[:can_dlc])

# create a raw socket and bind it to the 'vcan0' interface
s = socket.socket(socket.AF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
s.bind(('vcan0',))

while True:
    cf, addr = s.recvfrom(can_frame_size)

    print('Received: can_id=%x, can_dlc=%x, data=%s' % dissect_can_frame(cf))

    try:
        s.send(cf)
    except OSError:
        print('Error sending CAN frame')

    try:
        s.send(build_can_frame(0x01, b'\x01\x02\x03'))
    except OSError:
        print('Error sending CAN frame')

실행 간격이 너무 짧게 여러 번 예제를 실행하면 이 에러가 발생할 수 있습니다:

OSError: [Errno 98] Address already in use

이것은 이전 실행이 소켓을 TIME_WAIT 상태로 남겨 두었고, 즉시 재사용할 수 없기 때문입니다.

There is a socket flag to set, in order to prevent this, socket.SO_REUSEADDR:

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))

SO_REUSEADDR 플래그는 자연스러운 시간제한이 만료되기를 기다리지 않고 TIME_WAIT 상태의 지역 소켓을 재사용하도록 커널에 알립니다.

더 보기

(C로 하는) 소켓 프로그래밍에 대한 소개는 다음 논문을 참조하십시오:

An Introductory 4.3BSD Interprocess Communication Tutorial, Stuart Sechrest 저

An Advanced 4.3BSD Interprocess Communication Tutorial, Samuel J. Leffler 외 저,

둘 다 유닉스 프로그래머 매뉴얼, 보충 문서 1 (섹션 PS1:7과 PS1:8)에 있습니다. 다양한 소켓 관련 시스템 호출에 대한 플랫폼별 레퍼런스 자료는 소켓 의미의 세부 정보에 대한 중요한 소스입니다. 유닉스에서는 매뉴얼 페이지를 참조하십시오; 윈도우에서는, WinSock (또는 Winsock 2) 명세를 참조하십시오. IPv6 지원 API의 경우, 독자는 Basic Socket Interface Extensions for IPv6라는 제목의 RFC 3493 [https://datatracker.ietf.org/doc/html/rfc3493.html]를 참조하고 싶을 겁니다.

ssl — TLS/SSL wrapper for socket objects

소스 코드: Lib/ssl.py [https://github.com/python/cpython/tree/main/Lib/ssl.py]

This module provides access to Transport Layer Security (often known as “Secure Sockets Layer”) encryption and peer authentication facilities for network sockets, both client-side and server-side. This module uses the OpenSSL library. It is available on all modern Unix systems, Windows, macOS, and probably additional platforms, as long as OpenSSL is installed on that platform.

참고

Some behavior may be platform dependent, since calls are made to the operating system socket APIs. The installed version of OpenSSL may also cause variations in behavior. For example, TLSv1.3 comes with OpenSSL version 1.1.1.

경고

보안 고려 사항을 읽지 않고 이 모듈을 사용하지 마십시오. 그렇게 하면 ssl 모듈의 기본 설정이 반드시 여러분의 응용 프로그램에 적합하지는 않으므로 잘못된 보안 인식으로 이어질 수 있습니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

이 절에서는 ssl 모듈의 객체와 함수를 설명합니다; TLS, SSL 및 인증서에 대한보다 일반적인 정보는, 하단의 “더 보기” 절에 있는 문서를 참조하십시오.

This module provides a class, ssl.SSLSocket, which is derived from the socket.socket type, and provides a socket-like wrapper that also encrypts and decrypts the data going over the socket with SSL. It supports additional methods such as getpeercert(), which retrieves the certificate of the other side of the connection, cipher(), which retrieves the cipher being used for the secure connection or get_verified_chain(), get_unverified_chain() which retrieves certificate chain.

더욱 정교한 응용 프로그램의 경우, ssl.SSLContext 클래스는 설정과 인증서를 관리하는 데 도움이 되며, SSLContext.wrap_socket() 메서드를 통해 만들어진 SSL 소켓이 상속할 수 있습니다.

버전 3.5.3에서 변경: OpenSSL 1.1.0과의 링크를 지원하도록 갱신되었습니다

버전 3.6에서 변경: OpenSSL 0.9.8, 1.0.0 및 1.0.1은 폐지되었으며 더는 지원되지 않습니다. 미래에는 ssl 모듈이 최소한 OpenSSL 1.0.2 나 1.1.0을 요구할 것입니다.

버전 3.10에서 변경: PEP 644 [https://peps.python.org/pep-0644/] has been implemented. The ssl module requires OpenSSL 1.1.1 or newer.

Use of deprecated constants and functions result in deprecation warnings.

함수, 상수 및 예외

소켓 생성

Instances of SSLSocket must be created using the SSLContext.wrap_socket() method. The helper function create_default_context() returns a new context with secure default settings.

기본 컨텍스트와 IPv4/IPv6 이중 스택을 사용하는 클라이언트 소켓 예제:

import socket
import ssl

hostname = 'www.python.org'
context = ssl.create_default_context()

with socket.create_connection((hostname, 443)) as sock:
    with context.wrap_socket(sock, server_hostname=hostname) as ssock:
        print(ssock.version())

사용자 정의 컨텍스트와 IPv4를 사용하는 클라이언트 소켓 예제:

hostname = 'www.python.org'
# PROTOCOL_TLS_CLIENT requires valid cert chain and hostname
context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
context.load_verify_locations('path/to/cabundle.pem')

with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock:
    with context.wrap_socket(sock, server_hostname=hostname) as ssock:
        print(ssock.version())

localhost IPv4에서 리스닝하는 서버 소켓 예제:

context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
context.load_cert_chain('/path/to/certchain.pem', '/path/to/private.key')

with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock:
    sock.bind(('127.0.0.1', 8443))
    sock.listen(5)
    with context.wrap_socket(sock, server_side=True) as ssock:
        conn, addr = ssock.accept()
        ...

컨텍스트 생성

편리 함수는 공통 목적을 위한 SSLContext 객체를 만드는 데 도움이 됩니다.

ssl.create_default_context(purpose=Purpose.SERVER_AUTH, cafile=None, capath=None, cadata=None)

지정된 purpose를 위한 기본 설정으로 새 SSLContext 객체를 반환합니다. 설정은 ssl 모듈에 의해 선택되며, 일반적으로 SSLContext 생성자를 직접 호출할 때 보다 높은 보안 수준을 나타냅니다.

cafile, capath, cadata는, SSLContext.load_verify_locations()에서와 같이, 인증서 확인을 위해 신뢰할 수 있는 선택적 CA 인증서를 나타냅니다. 세 개 모두가 None이면, 이 함수는 대신 시스템의 기본 CA 인증서를 신뢰하도록 선택할 수 있습니다.

The settings are: PROTOCOL_TLS_CLIENT or PROTOCOL_TLS_SERVER, OP_NO_SSLv2, and OP_NO_SSLv3 with high encryption cipher suites without RC4 and without unauthenticated cipher suites. Passing SERVER_AUTH as purpose sets verify_mode to CERT_REQUIRED and either loads CA certificates (when at least one of cafile, capath or cadata is given) or uses SSLContext.load_default_certs() to load default CA certificates.

keylog_filename이 지원되고 환경 변수 SSLKEYLOGFILE이 설정될 때, create_default_context()는 키 로깅을 활성화합니다.

The default settings for this context include VERIFY_X509_PARTIAL_CHAIN and VERIFY_X509_STRICT. These make the underlying OpenSSL implementation behave more like a conforming implementation of RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html], in exchange for a small amount of incompatibility with older X.509 certificates.

참고

프로토콜, 옵션, 사이퍼 및 기타 설정은 사전 폐지 없이 언제든지 더욱 제한적인 값으로 변경될 수 있습니다. 이 값은 호환성과 보안 간의 적절한 균형을 나타냅니다.

응용 프로그램에 특정 설정이 필요하면, SSLContext를 만들어 설정을 직접 적용해야 합니다.

참고

특정 이전 클라이언트나 서버가 이 함수로 만든 SSLContext로 연결을 시도할 때 “Protocol or cipher suite mismatch”라는 에러가 발생하면, 이 함수가 OP_NO_SSLv3를 사용해서 제외하는 SSL3.0만 지원하는 것일 수 있습니다. SSL3.0은 완전히 망가진 [https://en.wikipedia.org/wiki/POODLE]것으로 널리 인식되고 있습니다. 이 함수를 계속 사용하면서 SSL 3.0 연결을 계속 허용하려면 다음과 같이 다시 활성화할 수 있습니다:

ctx = ssl.create_default_context(Purpose.CLIENT_AUTH)
ctx.options &= ~ssl.OP_NO_SSLv3

참고

This context enables VERIFY_X509_STRICT by default, which may reject pre-RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html] or malformed certificates that the underlying OpenSSL implementation otherwise would accept. While disabling this is not recommended, you can do so using:

ctx = ssl.create_default_context()
ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT

Added in version 3.4.

버전 3.4.4에서 변경: RC4는 기본 사이퍼 문자열에서 삭제되었습니다.

버전 3.6에서 변경: ChaCha20/Poly1305가 기본 사이퍼 문자열에 추가되었습니다.

3DES가 기본 사이퍼 문자열에서 삭제되었습니다.

버전 3.8에서 변경: SSLKEYLOGFILE에 대한 키 로깅 지원이 추가되었습니다.

버전 3.10에서 변경: The context now uses PROTOCOL_TLS_CLIENT or PROTOCOL_TLS_SERVER protocol instead of generic PROTOCOL_TLS.

버전 3.13에서 변경: The context now uses VERIFY_X509_PARTIAL_CHAIN and VERIFY_X509_STRICT in its default verify flags.

예외

exception ssl.SSLError

하부 SSL 구현(현재 OpenSSL 라이브러리에서 제공)으로부터의 에러를 알리기 위해 발생합니다. 이는 하부 네트워크 연결에 겹쳐진 상위 수준의 암호화와 인증 계층에서 문제가 있음을 나타냅니다. 이 에러는 OSError의 서브 형입니다. SSLError 인스턴스의 에러 코드와 메시지는 OpenSSL 라이브러리에 의해 제공됩니다.

버전 3.3에서 변경: SSLError는 socket.error의 서브 형이었습니다.

library

SSL, PEM 또는 X509와 같이, 에러가 발생한 OpenSSL 하위 모듈을 지정하는 문자열 기호입니다. 가능한 값의 범위는 OpenSSL 버전에 따라 다릅니다.

Added in version 3.3.

reason

이 에러가 발생한 이유를 나타내는 문자열 기호, 예를 들어, CERTIFICATE_VERIFY_FAILED. 가능한 값의 범위는 OpenSSL 버전에 따라 다릅니다.

Added in version 3.3.

exception ssl.SSLZeroReturnError

읽기나 쓰기를 시도하고 SSL 연결이 정상적으로 닫혔을 때 발생하는 SSLError의 서브 클래스. 이것이 하부 트랜스포트(TCP 읽기)가 닫혔음을 뜻하지는 않습니다.

Added in version 3.3.

exception ssl.SSLWantReadError

데이터를 읽거나 쓰려고 하지만, 요청을 만족하려면 하부 TCP 트랜스포트에서 데이터를 더 수신해야 할 때, 비 블로킹 SSL 소켓에 의해 발생하는 SSLError의 서브 클래스.

Added in version 3.3.

exception ssl.SSLWantWriteError

데이터를 읽거나 쓰려고 하지만, 요청을 만족하려면 하부 TCP 트랜스포트로 데이터를 더 보내야 할 때, 비 블로킹 SSL 소켓에 의해 발생하는 SSLError의 서브 클래스.

Added in version 3.3.

exception ssl.SSLSyscallError

SSL 소켓에서 작업을 수행하는 동안 시스템 에러를 만났을 때 발생하는 SSLError의 서브 클래스. 불행히도 원래의 errno 번호를 검사하는 쉬운 방법은 없습니다.

Added in version 3.3.

exception ssl.SSLEOFError

SSL 연결이 갑자기 종료되었을 때 발생하는 SSLError의 서브 클래스. 일반적으로, 이 에러가 발생하면 하부 트랜스포트를 다시 사용하지 않아야 합니다.

Added in version 3.3.

exception ssl.SSLCertVerificationError

인증서 유효성 검사가 실패했을 때 발생하는 SSLError의 서브 클래스.

Added in version 3.7.

verify_code

유효성 검사 에러를 나타내는 숫자 에러 번호.

verify_message

사람이 읽을 수 있는 유효성 검사 에러 문자열.

exception ssl.CertificateError

SSLCertVerificationError의 별칭.

버전 3.7에서 변경: 예외는 이제 SSLCertVerificationError의 별칭입니다.

난수 생성

ssl.RAND_bytes(num)

길이 num의 암호학적으로 강한 의사 난수 바이트열을 반환합니다. PRNG에 충분한 데이터가 시드(seed) 되지 않았거나 현재 RAND 메서드에서 지원되지 않는 연산이면 SSLError를 발생시킵니다. RAND_status()를 PRNG의 상태를 확인하는 데 사용할 수 있으며 RAND_add()는 PRNG를 시드 하는 데 사용할 수 있습니다.

거의 모든 응용 프로그램에서 os.urandom()을 선호합니다.

암호학적으로 강한 생성기의 요구 사항을 얻으려면 위키피디아 기사 Cryptographically secure pseudorandom number generator (CSPRNG) [https://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator]를 읽으십시오.

Added in version 3.3.

ssl.RAND_status()

SSL 의사 난수 생성기에 ‘충분한’ 임의성이 시드 되었으면 True를 반환하고, 그렇지 않으면 False를 반환합니다. ssl.RAND_egd()와 ssl.RAND_add()를 사용하여 의사 난수 생성기의 임의성을 높일 수 있습니다.

ssl.RAND_add(bytes, entropy)

Mix the given bytes into the SSL pseudo-random number generator. The parameter entropy (a float) is a lower bound on the entropy contained in string (so you can always use 0.0). See RFC 1750 [https://datatracker.ietf.org/doc/html/rfc1750.html] for more information on sources of entropy.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

인증서 처리

ssl.cert_time_to_seconds(cert_time)

인증서의 “notBefore” 나 “notAfter” 날짜를 나타내는 "%b %d %H:%M:%S %Y %Z" strptime 형식(C 로케일)의 cert_time 문자열이 지정하는 시간을 Epoch 이후 초 단위로 반환합니다.

여기 예제가 있습니다:

>>> import ssl
>>> timestamp = ssl.cert_time_to_seconds("Jan  5 09:34:43 2018 GMT")
>>> timestamp
1515144883
>>> from datetime import datetime
>>> print(datetime.utcfromtimestamp(timestamp))
2018-01-05 09:34:43

“notBefore” 나 “notAfter” 날짜는 GMT(RFC 5280 [https://datatracker.ietf.org/doc/html/rfc5280.html])를 사용해야 합니다.

버전 3.5에서 변경: 입력된 시간을 입력 문자열의 ‘GMT’ 시간대로 지정된 UTC 시간으로 해석합니다. 이전에는 지역 시간대가 사용되었습니다. 정수를 반환합니다 (입력 형식에는 부분 초가 없습니다).

ssl.get_server_certificate(addr, ssl_version=PROTOCOL_TLS_CLIENT, ca_certs=None[, timeout])

Given the address addr of an SSL-protected server, as a (hostname, port-number) pair, fetches the server’s certificate, and returns it as a PEM-encoded string. If ssl_version is specified, uses that version of the SSL protocol to attempt to connect to the server. If ca_certs is specified, it should be a file containing a list of root certificates, the same format as used for the cafile parameter in SSLContext.load_verify_locations(). The call will attempt to validate the server certificate against that set of root certificates, and will fail if the validation attempt fails. A timeout can be specified with the timeout parameter.

버전 3.3에서 변경: 이 함수는 이제 IPv6와 호환됩니다.

버전 3.5에서 변경: 최신 서버와의 호환성을 최대화하기 위해 기본 ssl_version이 PROTOCOL_SSLv3에서 PROTOCOL_TLS로 변경되었습니다.

버전 3.10에서 변경: The timeout parameter was added.

ssl.DER_cert_to_PEM_cert(DER_cert_bytes)

인증서가 DER-인코딩된 바이트열로 주어지면, 같은 인증서의 PEM-인코딩된 문자열 버전을 반환합니다.

ssl.PEM_cert_to_DER_cert(PEM_cert_string)

인증서가 ASCII PEM 문자열로 주어지면, 같은 인증서의 DER-인코딩된 바이트열 시퀀스를 반환합니다.

ssl.get_default_verify_paths()

OpenSSL의 기본 cafile 및 capath에 대한 경로가 있는 네임드 튜플을 반환합니다. 경로는 SSLContext.set_default_verify_paths()에서 사용하는 경로와 같습니다. 반환 값은 네임드 튜플 DefaultVerifyPaths입니다.:

cafile - cafile에 대한 확인된 경로나 파일이 존재하지 않으면 None,

capath - capath에 대한 확인된 경로나 디렉터리가 존재하지 않으면 None,

openssl_cafile_env - cafile을 가리키는 OpenSSL의 환경 키,

openssl_cafile - cafile에 대한 하드 코딩된 경로,

openssl_capath_env - capath를 가리키는 OpenSSL의 환경 키,

openssl_capath - capath 디렉터리에 대한 하드 코딩된 경로

Added in version 3.4.

ssl.enum_certificates(store_name)

윈도우의 시스템 인증서 저장소에서 인증서를 꺼냅니다. store_name은 CA, ROOT 또는 MY 중 하나일 수 있습니다. 윈도우가 추가 인증서 저장소를 제공 할 수도 있습니다.

이 함수는 (cert_bytes, encoding_type, trust) 튜플의 리스트를 반환합니다. encoding_type은 cert_bytes의 인코딩을 지정합니다. X.509 ASN.1 데이터를 위한 x509_asn이거나 PKCS#7 ASN.1 데이터를 위한 pkcs_7_asn입니다. Trust는 인증서의 목적을 OIDS 집합으로 지정하거나, 인증서가 모든 목적에 대해 신뢰할 수 있으면 정확히 True입니다.

예제:

>>> ssl.enum_certificates("CA")
[(b'data...', 'x509_asn', {'1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2'}),
 (b'data...', 'x509_asn', True)]

Availability: Windows.

Added in version 3.4.

ssl.enum_crls(store_name)

윈도우의 시스템 인증서 저장소에서 CRL을 꺼냅니다. store_name는 CA, ROOT 또는 MY 중 하나일 수 있습니다. 윈도우가 추가 인증서 저장소를 제공 할 수도 있습니다.

이 함수는 (cert_bytes, encoding_type, trust) 튜플의 리스트를 반환합니다. encoding_type은 cert_bytes의 인코딩을 지정합니다. X.509 ASN.1 데이터를 위한 x509_asn이거나 PKCS#7 ASN.1 데이터를 위한 pkcs_7_asn입니다.

Availability: Windows.

Added in version 3.4.

상수

모든 상수는 이제 enum.IntEnum 이나 enum.IntFlag 컬렉션입니다.

Added in version 3.6.

ssl.CERT_NONE

Possible value for SSLContext.verify_mode. Except for PROTOCOL_TLS_CLIENT, it is the default mode. With client-side sockets, just about any cert is accepted. Validation errors, such as untrusted or expired cert, are ignored and do not abort the TLS/SSL handshake.

서버 모드에서는, 클라이언트에서 인증서를 요청하지 않으므로 클라이언트는 클라이언트 인증서 인증을 위해 인증서를 보내지 않습니다.

아래의 보안 고려 사항의 논의를 참조하십시오.

ssl.CERT_OPTIONAL

Possible value for SSLContext.verify_mode. In client mode, CERT_OPTIONAL has the same meaning as CERT_REQUIRED. It is recommended to use CERT_REQUIRED for client-side sockets instead.

서버 모드에서는, 클라이언트 인증서 요청이 클라이언트로 전송됩니다. 클라이언트는 요청을 무시하거나 TLS 클라이언트 인증서 인증을 수행하기 위해 인증서를 보낼 수 있습니다. 클라이언트가 인증서를 보내기로 선택하면, 인증서가 유효성 검사됩니다. 모든 유효성 검사 에러는, TLS 핸드 셰이크를 즉시 중단합니다.

Use of this setting requires a valid set of CA certificates to be passed to SSLContext.load_verify_locations().

ssl.CERT_REQUIRED

Possible value for SSLContext.verify_mode. In this mode, certificates are required from the other side of the socket connection; an SSLError will be raised if no certificate is provided, or if its validation fails. This mode is not sufficient to verify a certificate in client mode as it does not match hostnames. check_hostname must be enabled as well to verify the authenticity of a cert. PROTOCOL_TLS_CLIENT uses CERT_REQUIRED and enables check_hostname by default.

서버 소켓에서, 이 모드는 필수 TLS 클라이언트 인증서 인증을 제공합니다. 클라이언트 인증서 요청이 클라이언트에 보내지고 클라이언트는 유효하고 신뢰할 수 있는 인증서를 제공해야 합니다.

Use of this setting requires a valid set of CA certificates to be passed to SSLContext.load_verify_locations().

class ssl.VerifyMode

CERT_* 상수의 enum.IntEnum 컬렉션.

Added in version 3.6.

ssl.VERIFY_DEFAULT

SSLContext.verify_flags의 가능한 값. 이 모드에서는 인증서 해지 목록(CRL)을 검사하지 않습니다. 기본적으로 OpenSSL은 CRL을 요구하지도 검사하지도 않습니다.

Added in version 3.4.

ssl.VERIFY_CRL_CHECK_LEAF

SSLContext.verify_flags의 가능한 값. 이 모드에서는, 피어 인증서만 확인할 뿐 중간 CA 인증서는 확인하지 않습니다. 이 모드는 피어 인증서의 발급자(그것의 직계 조상 CA)가 서명한 유효한 CRL을 요구합니다. 적절한 CRL이 SSLContext.load_verify_locations로 로드되지 않았으면 유효성 검사가 실패합니다.

Added in version 3.4.

ssl.VERIFY_CRL_CHECK_CHAIN

SSLContext.verify_flags의 가능한 값. 이 모드에서는, 피어 인증서 체인의 모든 인증서에 대한 CRL이 확인됩니다.

Added in version 3.4.

ssl.VERIFY_X509_STRICT

망가진 X.509 인증서에 대한 우회를 사용하지 못하도록 하는 SSLContext.verify_flags의 가능한 값.

Added in version 3.4.

ssl.VERIFY_ALLOW_PROXY_CERTS

Possible value for SSLContext.verify_flags to enables proxy certificate verification.

Added in version 3.10.

ssl.VERIFY_X509_TRUSTED_FIRST

SSLContext.verify_flags의 가능한 값. OpenSSL이 인증서의 유효성을 검사하기 위해 트러스트 체인을 구축할 때 신뢰할 수 있는 인증서를 선호하도록 지시합니다. 이 플래그는 기본적으로 활성화됩니다.

Added in version 3.4.4.

ssl.VERIFY_X509_PARTIAL_CHAIN

Possible value for SSLContext.verify_flags. It instructs OpenSSL to accept intermediate CAs in the trust store to be treated as trust-anchors, in the same way as the self-signed root CA certificates. This makes it possible to trust certificates issued by an intermediate CA without having to trust its ancestor root CA.

Added in version 3.10.

class ssl.VerifyFlags

VERIFY_* 상수의 enum.IntFlag 컬렉션.

Added in version 3.6.

ssl.PROTOCOL_TLS

클라이언트와 서버가 모두 지원하는 가장 높은 프로토콜 버전을 선택합니다. 이름에도 불구하고, 이 옵션은 “SSL” 과 “TLS” 프로토콜을 모두 선택할 수 있습니다.

Added in version 3.6.

버전 3.10부터 폐지됨: TLS clients and servers require different default settings for secure communication. The generic TLS protocol constant is deprecated in favor of PROTOCOL_TLS_CLIENT and PROTOCOL_TLS_SERVER.

ssl.PROTOCOL_TLS_CLIENT

Auto-negotiate the highest protocol version that both the client and server support, and configure the context client-side connections. The protocol enables CERT_REQUIRED and check_hostname by default.

Added in version 3.6.

ssl.PROTOCOL_TLS_SERVER

Auto-negotiate the highest protocol version that both the client and server support, and configure the context server-side connections.

Added in version 3.6.

ssl.PROTOCOL_SSLv23

PROTOCOL_TLS의 별칭.

버전 3.6부터 폐지됨: 대신 PROTOCOL_TLS를 사용하십시오.

ssl.PROTOCOL_SSLv3

채널 암호화 프로토콜로 SSL 버전 3을 선택합니다.

This protocol is not available if OpenSSL is compiled with the no-ssl3 option.

경고

SSL 버전 3은 안전하지 않습니다. 사용하지 말도록 강력히 권고합니다.

버전 3.6부터 폐지됨: OpenSSL has deprecated all version specific protocols. Use the default protocol PROTOCOL_TLS_SERVER or PROTOCOL_TLS_CLIENT with SSLContext.minimum_version and SSLContext.maximum_version instead.

ssl.PROTOCOL_TLSv1

채널 암호화 프로토콜로 TLS 버전 1.0을 선택합니다.

버전 3.6부터 폐지됨: OpenSSL has deprecated all version specific protocols.

ssl.PROTOCOL_TLSv1_1

채널 암호화 프로토콜로 TLS 버전 1.1을 선택합니다. openssl 버전 1.0.1+ 에서만 사용할 수 있습니다.

Added in version 3.4.

버전 3.6부터 폐지됨: OpenSSL has deprecated all version specific protocols.

ssl.PROTOCOL_TLSv1_2

Selects TLS version 1.2 as the channel encryption protocol. Available only with openssl version 1.0.1+.

Added in version 3.4.

버전 3.6부터 폐지됨: OpenSSL has deprecated all version specific protocols.

ssl.OP_ALL

다른 SSL 구현에 있는 다양한 버그에 대한 해결 방법을 활성화합니다. 이 옵션은 기본적으로 설정됩니다. 반드시 OpenSSL의 SSL_OP_ALL 상수와 같은 플래그를 설정할 필요는 없습니다.

Added in version 3.2.

ssl.OP_NO_SSLv2

SSLv2 연결을 방지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 SSLv2를 프로토콜 버전으로 선택하지 못하도록 합니다.

Added in version 3.2.

버전 3.6부터 폐지됨: SSLv2는 폐지되었습니다.

ssl.OP_NO_SSLv3

SSLv3 연결을 방지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 프로토콜 버전으로 SSLv3을 선택하지 못하게 합니다.

Added in version 3.2.

버전 3.6부터 폐지됨: SSLv3은 폐지되었습니다.

ssl.OP_NO_TLSv1

TLSv1 연결을 금지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 TLSv1을 프로토콜 버전으로 선택하지 못하게 합니다.

Added in version 3.2.

버전 3.7부터 폐지됨: 이 옵션은 OpenSSL 1.1.0부터 폐지되었습니다, 새로운 SSLContext.minimum_version과 SSLContext.maximum_version을 대신 사용하십시오.

ssl.OP_NO_TLSv1_1

TLSv1.1 연결을 금지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 TLSv1.1을 프로토콜 버전으로 선택하지 못하게 합니다. openssl 버전 1.0.1+ 에서만 사용할 수 있습니다.

Added in version 3.4.

버전 3.7부터 폐지됨: 이 옵션은 OpenSSL 1.1.0부터 폐지되었습니다.

ssl.OP_NO_TLSv1_2

TLSv1.2 연결을 방지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 프로토콜 버전으로 TLSv1.2를 선택하지 못하게 합니다. openssl 버전 1.0.1+ 에서만 사용할 수 있습니다.

Added in version 3.4.

버전 3.7부터 폐지됨: 이 옵션은 OpenSSL 1.1.0부터 폐지되었습니다.

ssl.OP_NO_TLSv1_3

TLSv1.3 연결을 방지합니다. 이 옵션은 PROTOCOL_TLS와 결합해서만 적용할 수 있습니다. 피어가 프로토콜 버전으로 TLSv1.3을 선택하지 못하게 합니다. TLS 1.3은 OpenSSL 1.1.1 이상에서 사용할 수 있습니다. 파이썬이 OpenSSL의 이전 버전에 대해 컴파일되면, 플래그의 기본값은 0입니다.

Added in version 3.6.3.

버전 3.7부터 폐지됨: The option is deprecated since OpenSSL 1.1.0. It was added to 2.7.15 and 3.6.3 for backwards compatibility with OpenSSL 1.0.2.

ssl.OP_NO_RENEGOTIATION

TLSv1.2와 그 이전 버전에서 모든 재협상을 비활성화합니다. HelloRequest 메시지를 보내지 않고, ClientHello를 통한 재협상 요청을 무시합니다.

이 옵션은 OpenSSL 1.1.0h 이상에서만 사용할 수 있습니다.

Added in version 3.7.

ssl.OP_CIPHER_SERVER_PREFERENCE

클라이언트보다는 서버의 사이퍼 순서 선호를 사용합니다. 이 옵션은 클라이언트 소켓과 SSLv2 서버 소켓에는 영향을 미치지 않습니다.

Added in version 3.3.

ssl.OP_SINGLE_DH_USE

Prevents reuse of the same DH key for distinct SSL sessions. This improves forward secrecy but requires more computational resources. This option only applies to server sockets.

Added in version 3.3.

ssl.OP_SINGLE_ECDH_USE

Prevents reuse of the same ECDH key for distinct SSL sessions. This improves forward secrecy but requires more computational resources. This option only applies to server sockets.

Added in version 3.3.

ssl.OP_ENABLE_MIDDLEBOX_COMPAT

TLS 1.3 연결을 더 TLS 1.2 연결처럼 보이게 하려고 TLS 1.3 핸드 셰이크에서 더미 암호 변경 사양(CCS - Change Cipher Spec) 메시지를 보냅니다.

이 옵션은 OpenSSL 1.1.1 이상에서만 사용할 수 있습니다.

Added in version 3.8.

ssl.OP_NO_COMPRESSION

SSL 채널에서 압축을 사용하지 않습니다. 응용 프로그램 프로토콜이 자체 압축 방법을 지원할 때 유용합니다.

Added in version 3.3.

class ssl.Options

OP_* 상수의 enum.IntFlag 컬렉션.

ssl.OP_NO_TICKET

클라이언트 측에서 세션 티켓을 요청하지 못하게 합니다.

Added in version 3.6.

ssl.OP_IGNORE_UNEXPECTED_EOF

Ignore unexpected shutdown of TLS connections.

This option is only available with OpenSSL 3.0.0 and later.

Added in version 3.10.

ssl.OP_ENABLE_KTLS

Enable the use of the kernel TLS. To benefit from the feature, OpenSSL must have been compiled with support for it, and the negotiated cipher suites and extensions must be supported by it (a list of supported ones may vary by platform and kernel version).

Note that with enabled kernel TLS some cryptographic operations are performed by the kernel directly and not via any available OpenSSL Providers. This might be undesirable if, for example, the application requires all cryptographic operations to be performed by the FIPS provider.

This option is only available with OpenSSL 3.0.0 and later.

Added in version 3.12.

ssl.OP_LEGACY_SERVER_CONNECT

Allow legacy insecure renegotiation between OpenSSL and unpatched servers only.

Added in version 3.12.

ssl.HAS_ALPN

OpenSSL 라이브러리가 RFC 7301 [https://datatracker.ietf.org/doc/html/rfc7301.html]에서 설명한 대로 응용 계층 프로토콜 협상(Application-Layer Protocol Negotiation) TLS 확장에 대한 지원을 기본 제공하는지 여부

Added in version 3.5.

ssl.HAS_NEVER_CHECK_COMMON_NAME

OpenSSL 라이브러리가 SCN(subject common name)을 검사하지 않는 지원을 기본 제공하고 SSLContext.hostname_checks_common_name가 쓰기 가능한지 아닌지.

Added in version 3.7.

ssl.HAS_ECDH

OpenSSL 라이브러리가 타원 곡선(Elliptic Curve) 기반 Diffie-Hellman 키 교환 지원을 기본 제공하는지 여부. 기능이 배포자에 의해 명시적으로 비활성화되어 있지 않은 한, 참이어야 합니다.

Added in version 3.3.

ssl.HAS_SNI

OpenSSL 라이브러리가 서버 이름 표시(Server Name Indication) 확장(RFC 6066 [https://datatracker.ietf.org/doc/html/rfc6066.html]에 정의된 대로)에 대한 지원을 기본 제공하는지 여부.

Added in version 3.2.

ssl.HAS_NPN

OpenSSL 라이브러리가 Application Layer Protocol Negotiation [https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation]에 설명된 대로 NPN(Next Protocol Negotiation)에 대한 지원을 기본 제공하는지 여부. 참이면 SSLContext.set_npn_protocols() 메서드를 사용하여 지원할 프로토콜을 알릴 수 있습니다.

Added in version 3.3.

ssl.HAS_SSLv2

OpenSSL 라이브러리가 SSL 2.0 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_SSLv3

OpenSSL 라이브러리가 SSL 3.0 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_TLSv1

OpenSSL 라이브러리가 TLS 1.0 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_TLSv1_1

OpenSSL 라이브러리가 TLS 1.1 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_TLSv1_2

OpenSSL 라이브러리가 TLS 1.2 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_TLSv1_3

OpenSSL 라이브러리가 TLS 1.3 프로토콜 지원을 기본 제공하는지 여부

Added in version 3.7.

ssl.HAS_PSK

Whether the OpenSSL library has built-in support for TLS-PSK.

Added in version 3.13.

ssl.CHANNEL_BINDING_TYPES

지원되는 TLS 채널 바인딩 유형의 리스트. 이 리스트의 문자열은 SSLSocket.get_channel_binding()에 대한 인자로 사용될 수 있습니다.

Added in version 3.3.

ssl.OPENSSL_VERSION

인터프리터에 의해 로드된 OpenSSL 라이브러리의 버전 문자열:

>>> ssl.OPENSSL_VERSION
'OpenSSL 1.0.2k  26 Jan 2017'

Added in version 3.2.

ssl.OPENSSL_VERSION_INFO

OpenSSL 라이브러리에 대한 버전 정보를 나타내는 5개의 정수 튜플:

>>> ssl.OPENSSL_VERSION_INFO
(1, 0, 2, 11, 15)

Added in version 3.2.

ssl.OPENSSL_VERSION_NUMBER

단일 정수로 표현되는, OpenSSL 라이브러리의 원시 버전 번호:

>>> ssl.OPENSSL_VERSION_NUMBER
268443839
>>> hex(ssl.OPENSSL_VERSION_NUMBER)
'0x100020bf'

Added in version 3.2.

ssl.ALERT_DESCRIPTION_HANDSHAKE_FAILURE

ssl.ALERT_DESCRIPTION_INTERNAL_ERROR

ALERT_DESCRIPTION_*

RFC 5246 [https://datatracker.ietf.org/doc/html/rfc5246.html] 및 기타의 경고 설명. IANA TLS Alert Registry [https://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-6]에는 이 목록과 그 의미가 정의된 RFC에 대한 참조가 들어 있습니다.

SSLContext.set_servername_callback()에서 콜백 함수의 반환 값으로 사용됩니다.

Added in version 3.4.

class ssl.AlertDescription

ALERT_DESCRIPTION_* 상수의 enum.IntEnum 컬렉션.

Added in version 3.6.

Purpose.SERVER_AUTH

Option for create_default_context() and SSLContext.load_default_certs(). This value indicates that the context may be used to authenticate web servers (therefore, it will be used to create client-side sockets).

Added in version 3.4.

Purpose.CLIENT_AUTH

Option for create_default_context() and SSLContext.load_default_certs(). This value indicates that the context may be used to authenticate web clients (therefore, it will be used to create server-side sockets).

Added in version 3.4.

class ssl.SSLErrorNumber

SSL_ERROR_* 상수의 enum.IntEnum 컬렉션.

Added in version 3.6.

class ssl.TLSVersion

SSLContext.maximum_version과 SSLContext.minimum_version 용 SSL과 TLS 버전의 enum.IntEnum 컬렉션.

Added in version 3.7.

TLSVersion.MINIMUM_SUPPORTED

TLSVersion.MAXIMUM_SUPPORTED

지원되는 SSL 또는 TLS 버전의 최소 또는 최대. 이것들은 마법 상수(magic constant)입니다. 이들의 값은 사용 가능한 가장 낮거나 높은 TLS/SSL 버전을 반영하지 않습니다.

TLSVersion.SSLv3

TLSVersion.TLSv1

TLSVersion.TLSv1_1

TLSVersion.TLSv1_2

TLSVersion.TLSv1_3

SSL 3.0 에서 TLS 1.3.

버전 3.10부터 폐지됨: All TLSVersion members except TLSVersion.TLSv1_2 and TLSVersion.TLSv1_3 are deprecated.

SSL 소켓

class ssl.SSLSocket(socket.socket)

SSL 소켓은 다음과 같은 소켓 객체 메서드를 제공합니다:

accept()

bind()

close()

connect()

detach()

fileno()

getpeername(), getsockname()

getsockopt(), setsockopt()

gettimeout(), settimeout(), setblocking()

listen()

makefile()

recv(), recv_into() (but passing a non-zero flags argument is not allowed)

send(), sendall() (with the same limitation)

sendfile() (but os.sendfile will be used for plain-text sockets only, else send() will be used)

shutdown()

그러나 SSL (및 TLS) 프로토콜은 TCP 위에 자체 프레임을 가지고 있으므로, SSL 소켓 추상화는 특정 측면에서 정상적인 OS 수준 소켓의 사양에서 벗어날 수 있습니다. 특히 비 블로킹 소켓에 대한 참고 사항을 보십시오.

SSLSocket의 인스턴스는 SSLContext.wrap_socket() 메서드를 사용하여 민들어야 합니다.

버전 3.5에서 변경: sendfile() 메서드가 추가되었습니다.

버전 3.5에서 변경: The shutdown() does not reset the socket timeout each time bytes are received or sent. The socket timeout is now the maximum total duration of the shutdown.

버전 3.6부터 폐지됨: SSLSocket 인스턴스를 직접 만드는 것은 폐지되었습니다, SSLContext.wrap_socket()를 사용하여 소켓을 감싸십시오.

버전 3.7에서 변경: SSLSocket 인스턴스는 wrap_socket()로 만들어야 합니다. 이전 버전에서는 직접 인스턴스를 만들 수 있었습니다. 이것은 문서로 만들어지거나 공식적으로 지원된 적이 없습니다.

버전 3.10에서 변경: Python now uses SSL_read_ex and SSL_write_ex internally. The functions support reading and writing of data larger than 2 GB. Writing zero-length data no longer fails with a protocol violation error.

SSL 소켓에는 다음과 같은 추가 메서드와 어트리뷰트도 있습니다:

SSLSocket.read(len=1024, buffer=None)

SSL 소켓에서 최대 len 바이트의 데이터를 읽고 그 결과를 bytes 인스턴스로 반환합니다. buffer가 지정되면, 대신 버퍼로 읽어 들이고, 읽은 바이트 수를 반환합니다.

소켓이 비 블로킹이고 읽기가 블록 되려고 하면 SSLWantReadError 나 SSLWantWriteError를 발생시킵니다.

언제나 재협상이 가능하므로, read()를 호출해도 쓰기 연산이 발생할 수 있습니다.

버전 3.5에서 변경: The socket timeout is no longer reset each time bytes are received or sent. The socket timeout is now the maximum total duration to read up to len bytes.

버전 3.6부터 폐지됨: read() 대신 recv()를 사용하십시오.

SSLSocket.write(buf)

SSL 소켓에 buf를 기록하고, 기록한 바이트 수를 돌려줍니다. buf 인자는 버퍼 인터페이스를 지원하는 객체여야 합니다.

소켓이 비 블로킹이고, 쓰기가 블록 하려고 하면 SSLWantReadError 나 SSLWantWriteError를 발생시킵니다.

언제나 재협상이 가능하므로, write()를 호출해도 읽기 연산이 발생할 수 있습니다.

버전 3.5에서 변경: The socket timeout is no longer reset each time bytes are received or sent. The socket timeout is now the maximum total duration to write buf.

버전 3.6부터 폐지됨: write() 대신 send()를 사용하십시오.

참고

read() 과 write() 메서드는 암호화되지 않은 응용 프로그램 수준 데이터를 읽고 쓰고 그것을 암호화되고 와이어 수준(wire-level) 데이터로 복호화/암호화하는 저수준 메서드입니다. 이 메서드는 활성화된 SSL 연결, 즉, 핸드 셰이크가 완료되고, SSLSocket.unwrap()가 호출되지 않은 것이 필요합니다.

일반적으로 이러한 메서드 대신 recv() 와 send()와 같은 소켓 API 메서드를 사용해야합니다.

SSLSocket.do_handshake()

SSL 설정 핸드 셰이크를 수행합니다.

버전 3.4에서 변경: 핸드 셰이크 메서드는 소켓의 context의 check_hostname 어트리뷰트가 참일 때 match_hostname()도 수행합니다.

버전 3.5에서 변경: The socket timeout is no longer reset each time bytes are received or sent. The socket timeout is now the maximum total duration of the handshake.

버전 3.7에서 변경: Hostname or IP address is matched by OpenSSL during handshake. The function match_hostname() is no longer used. In case OpenSSL refuses a hostname or IP address, the handshake is aborted early and a TLS alert message is sent to the peer.

SSLSocket.getpeercert(binary_form=False)

연결의 다른 끝의 피어에 대한 인증서가 없으면 None을 반환합니다. SSL 핸드 셰이크가 아직 수행되지 않았으면, ValueError를 발생시킵니다.

binary_form 매개 변수가 False이고, 피어에서 인증서를 받았으면, 이 메서드는 dict 인스턴스를 반환합니다. 인증서의 유효성을 검사하지 않았으면, 딕셔너리는 비어 있습니다. 인증서의 유효성을 검사했으면 subject(인증서가 발행된 주체)와 issuer(인증서를 발급한 주체)와 같은 몇 가지 키가 있는 dict를 반환합니다. 인증서가 SAN(Subject Alternative Name) 확장(RFC 3280 [https://datatracker.ietf.org/doc/html/rfc3280.html] 참조)의 인스턴스를 포함하면 딕셔너리에 subjectAltName 키도 있습니다.

subject 와 issuer 필드는 각 필드에 대한 인증서의 데이터 구조에 제공된 RDN(relative distinguished name)의 시퀀스를 포함하는 튜플이며, 각 RDN은 이름-값 쌍의 시퀀스입니다. 실제 예를 들어 보겠습니다:

{'issuer': ((('countryName', 'IL'),),
            (('organizationName', 'StartCom Ltd.'),),
            (('organizationalUnitName',
              'Secure Digital Certificate Signing'),),
            (('commonName',
              'StartCom Class 2 Primary Intermediate Server CA'),)),
 'notAfter': 'Nov 22 08:15:19 2013 GMT',
 'notBefore': 'Nov 21 03:09:52 2011 GMT',
 'serialNumber': '95F0',
 'subject': ((('description', '571208-SLe257oHY9fVQ07Z'),),
             (('countryName', 'US'),),
             (('stateOrProvinceName', 'California'),),
             (('localityName', 'San Francisco'),),
             (('organizationName', 'Electronic Frontier Foundation, Inc.'),),
             (('commonName', '*.eff.org'),),
             (('emailAddress', 'hostmaster@eff.org'),)),
 'subjectAltName': (('DNS', '*.eff.org'), ('DNS', 'eff.org')),
 'version': 3}

binary_form 매개 변수가 True이고, 인증서가 제공되었으면, 이 메서드는 전체 인증서의 DER-인코딩 형식을 바이트 시퀀스로 반환하고, 피어가 인증서를 제공하지 않았으면 None을 반환합니다. 피어가 인증서를 제공하는지는 SSL 소켓의 역할에 따라 다릅니다:

클라이언트 SSL 소켓의 경우, 서버는 유효성 검사가 필요한지에 관계없이 항상 인증서를 제공합니다.

서버 SSL 소켓의 경우, 클라이언트는 서버가 요청할 때만 인증서를 제공합니다; 따라서 CERT_NONE(CERT_OPTIONAL 나 CERT_REQUIRED 대신)을 사용하면 getpeercert()는 None을 반환합니다.

See also SSLContext.check_hostname.

버전 3.2에서 변경: 반환된 딕셔너리에는 issuer 와 notBefore와 같은 추가 항목이 포함됩니다.

버전 3.4에서 변경: 핸드 셰이크가 완료되지 않았으면 ValueError가 발생합니다. 반환된 딕셔너리에는 crlDistributionPoints, caIssuers 및 OCSP URI와 같은 추가 X509v3 확장 항목이 포함됩니다.

버전 3.9에서 변경: IPv6 주소 문자열에는 더는 후행 줄 바꿈이 없습니다.

SSLSocket.get_verified_chain()

Returns verified certificate chain provided by the other end of the SSL channel as a list of DER-encoded bytes. If certificate verification was disabled method acts the same as get_unverified_chain().

Added in version 3.13.

SSLSocket.get_unverified_chain()

Returns raw certificate chain provided by the other end of the SSL channel as a list of DER-encoded bytes.

Added in version 3.13.

SSLSocket.cipher()

사용되는 사이퍼의 이름, 그것의 사용을 정의하는 SSL 프로토콜의 버전 및 사용되는 비밀 비트의 수를 포함하는 3-튜플을 반환합니다. 연결이 이루어지지 않았으면 None을 반환합니다.

SSLSocket.shared_ciphers()

Return the list of ciphers available in both the client and server. Each entry of the returned list is a three-value tuple containing the name of the cipher, the version of the SSL protocol that defines its use, and the number of secret bits the cipher uses. shared_ciphers() returns None if no connection has been established or the socket is a client socket.

Added in version 3.5.

SSLSocket.compression()

사용되는 압축 알고리즘을 문자열로 반환하거나, 연결이 압축되지 않으면 None을 반환합니다.

상위-수준 프로토콜이 자체 압축 메커니즘을 지원하면, OP_NO_COMPRESSION을 사용하여 SSL-수준 압축을 비활성화할 수 있습니다.

Added in version 3.3.

SSLSocket.get_channel_binding(cb_type='tls-unique')

현재 연결에 대한 채널 바인딩 데이터를 바이트열 객체로 가져옵니다. 연결되어 있지 않거나 핸드 셰이크가 완료되지 않았으면 None을 반환합니다.

cb_type 매개 변수를 사용하여 원하는 채널 바인딩 유형을 선택할 수 있습니다. 유효한 채널 바인딩 유형은 CHANNEL_BINDING_TYPES 리스트에 나열됩니다. 현재는 RFC 5929 [https://datatracker.ietf.org/doc/html/rfc5929.html]가 정의한 ‘tls-unique’ 채널 바인딩만 지원됩니다. 지원되지 않는 채널 바인딩 유형이 요청되면 ValueError가 발생합니다.

Added in version 3.3.

SSLSocket.selected_alpn_protocol()

TLS 핸드 셰이크 중에 선택된 프로토콜을 반환합니다. SSLContext.set_alpn_protocols()가 호출되지 않았거나, 상대방이 ALPN을 지원하지 않거나, 이 소켓이 클라이언트가 제안한 프로토콜 중 어떤 것도 지원하지 않거나, 핸드 셰이크가 아직 발생하지 않았으면 None이 반환됩니다.

Added in version 3.5.

SSLSocket.selected_npn_protocol()

TLS/SSL 핸드 셰이크 중에 선택된 상위-수준의 프로토콜을 반환합니다. SSLContext.set_npn_protocols()가 호출되지 않았거나, 상대방이 NPN을 지원하지 않거나, 핸드 셰이크가 아직 발생하지 않았으면 None을 반환합니다.

Added in version 3.3.

버전 3.10부터 폐지됨: NPN has been superseded by ALPN

SSLSocket.unwrap()

SSL 종료 핸드 셰이크를 수행해서 하부 소켓에서 TLS 계층을 제거하고, 하부 소켓 객체를 반환합니다. 이것은 연결을 통한 암호화된 연산에서 암호화되지 않은 것으로 이동하는 데 사용할 수 있습니다. 원래 소켓이 아닌 반환된 소켓을 연결의 다른 쪽과 계속 통신하기 위해 항상 사용해야 합니다.

SSLSocket.verify_client_post_handshake()

TLS 1.3 클라이언트로부터 PHA(post-handshake authentication)를 요청합니다. PHA는 양쪽에서 PHA가 활성화된 초기 TLS 핸드 셰이크 후에 서버 측 소켓에서 TLS 1.3 연결에 대해서만 시작할 수 있습니다, SSLContext.post_handshake_auth를 참조하세요.

이 메서드는 즉시 인증서 교환을 수행하지 않습니다. 서버 측은 다음 쓰기 이벤트 중에 CertificateRequest를 보내고 클라이언트가 다음 읽기 이벤트에서 인증서로 응답할 것으로 기대합니다.

사전 조건이 모두 충족되지 않으면 (예를 들어, TLS 1.3이 아니거나 PHA가 활성화되지 않았을 때), SSLError가 발생합니다.

참고

OpenSSL 1.1.1과 TLS 1.3이 활성화된 경우에만 사용할 수 있습니다. TLS 1.3 지원이 없으면, 이 메서드는 NotImplementedError를 발생시킵니다.

Added in version 3.8.

SSLSocket.version()

Return the actual SSL protocol version negotiated by the connection as a string, or None if no secure connection is established. As of this writing, possible return values include "SSLv2", "SSLv3", "TLSv1", "TLSv1.1" and "TLSv1.2". Recent OpenSSL versions may define more return values.

Added in version 3.5.

SSLSocket.pending()

접속에 계류 중인, 읽기용으로 이미 복호화된 바이트의 수를 돌려줍니다.

SSLSocket.context

The SSLContext object this SSL socket is tied to.

Added in version 3.2.

SSLSocket.server_side

서버 측 소켓에서는 True이고 클라이언트 측 소켓에서는 False 인 논릿값.

Added in version 3.2.

SSLSocket.server_hostname

서버의 호스트 이름: str 형, 또는 서버 측 소켓이거나 호스트 이름이 생성자에 지정되지 않았으면 None.

Added in version 3.2.

버전 3.7에서 변경: 어트리뷰트는 이제 항상 ASCII 텍스트입니다. server_hostname이 국제화 된 도메인 이름(IDN)일 때, 이 어트리뷰트는 이제 U-레이블 형식("pythön.org") 대신 A-레이블 형식("xn--pythn-mua.org")을 저장합니다.

SSLSocket.session

이 SSL 연결을 위한 SSLSession. 이 세션은 TLS 핸드 셰이크가 수행된 후 클라이언트와 서버 측 소켓에서 사용할 수 있습니다. 클라이언트 소켓의 경우 세션을 다시 사용하기 위해 do_handshake()가 호출되기 전에 세션을 설정할 수 있습니다.

Added in version 3.6.

SSLSocket.session_reused

Added in version 3.6.

SSL 컨텍스트

Added in version 3.2.

SSL 컨텍스트는 SSL 구성 옵션, 인증서 및 개인 키와 같이 단일 SSL 연결보다 수명이 긴 다양한 데이터를 보관합니다. 또한, 같은 클라이언트의 반복된 연결 속도를 높이기 위해 서버 측 소켓에 대한 SSL 세션 캐시를 관리합니다.

class ssl.SSLContext(protocol=None)

새 SSL 컨텍스트를 만듭니다. protocol를 전달할 수 있는데, 이 모듈에 정의된 PROTOCOL_* 상수 중 하나여야 합니다. 매개 변수는 사용할 SSL 프로토콜의 버전을 지정합니다. 일반적으로 서버는 특정 프로토콜 버전을 선택하고, 클라이언트는 서버의 선택에 적응해야 합니다. 대부분의 버전은 다른 버전과 상호 운용할 수 없습니다. 지정하지 않으면, 기본값은 PROTOCOL_TLS입니다; 다른 버전과의 호환성이 가장 뛰어납니다.

다음은 클라이언트의 어느 버전(행)이 서버의 어떤 버전(열)에 연결할 수 있는지 보여주는 표입니다:

클라이언트 / 서버

SSLv2

SSLv3

TLS [3]

TLSv1

TLSv1.1

TLSv1.2

SSLv2

yes

no

no [1]

no

no

no

SSLv3

no

yes

no [2]

no

no

no

TLS (SSLv23) [3]

no [1]

no [2]

yes

yes

yes

yes

TLSv1

no

no

yes

yes

no

no

TLSv1.1

no

no

yes

no

yes

no

TLSv1.2

no

no

yes

no

no

yes

각주

[1] (1,2)

SSLContext는 기본적으로 OP_NO_SSLv2로 SSLv2를 비활성화합니다.

[2] (1,2)

SSLContext는 기본적으로 OP_NO_SSLv3으로 SSLv3을 비활성화합니다.

[3] (1,2)

TLS 1.3 프로토콜은 OpenSSL >= 1.1.1에서 PROTOCOL_TLS로 사용할 수 있습니다. TLS 1.3만을 위한 전용 PROTOCOL 상수는 없습니다.

더 보기

create_default_context()는 ssl 모듈이 주어진 목적을 위한 보안 설정을 선택할 수 있게 합니다.

버전 3.6에서 변경: The context is created with secure default values. The options OP_NO_COMPRESSION, OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE, OP_NO_SSLv2, and OP_NO_SSLv3 (except for PROTOCOL_SSLv3) are set by default. The initial cipher suite list contains only HIGH ciphers, no NULL ciphers and no MD5 ciphers.

버전 3.10부터 폐지됨: SSLContext without protocol argument is deprecated. The context class will either require PROTOCOL_TLS_CLIENT or PROTOCOL_TLS_SERVER protocol in the future.

버전 3.10에서 변경: The default cipher suites now include only secure AES and ChaCha20 ciphers with forward secrecy and security level 2. RSA and DH keys with less than 2048 bits and ECC keys with less than 224 bits are prohibited. PROTOCOL_TLS, PROTOCOL_TLS_CLIENT, and PROTOCOL_TLS_SERVER use TLS 1.2 as minimum TLS version.

참고

SSLContext only supports limited mutation once it has been used by a connection. Adding new certificates to the internal trust store is allowed, but changing ciphers, verification settings, or mTLS certificates may result in surprising behavior.

참고

SSLContext is designed to be shared and used by multiple connections. Thus, it is thread-safe as long as it is not reconfigured after being used by a connection.

SSLContext 객체에는 다음과 같은 메서드와 어트리뷰트가 있습니다:

SSLContext.cert_store_stats()

로드된 X.509 인증서 수량, CA 인증서로 표시된 X.509 인증서 및 인증서 취소 목록(CRL)의 수에 대한 통계를 딕셔너리로 가져옵니다.

하나의 CA 인증서와 다른 인증서 하나를 가진 컨텍스트 예:

>>> context.cert_store_stats()
{'crl': 0, 'x509_ca': 1, 'x509': 2}

Added in version 3.4.

SSLContext.load_cert_chain(certfile, keyfile=None, password=None)

Load a private key and the corresponding certificate. The certfile string must be the path to a single file in PEM format containing the certificate as well as any number of CA certificates needed to establish the certificate’s authenticity. The keyfile string, if present, must point to a file containing the private key. Otherwise the private key will be taken from certfile as well. See the discussion of 인증서 for more information on how the certificate is stored in the certfile.

password 인자는 개인 키의 복호화를 위한 암호를 얻기 위해 호출하는 함수가 될 수 있습니다. 개인 키가 암호화되어있고 암호가 필요한 경우에만 호출됩니다. 인자 없이 호출되며, 문자열, 바이트열 또는 bytearray를 반환해야 합니다. 반환 값이 문자열이면 키를 해독하기 전에 UTF-8로 인코딩됩니다. 또는 문자열, 바이트열 또는 bytearray 값을 password 인자로 직접 제공할 수 있습니다. 개인 키가 암호화되지 않고 암호가 필요 없으면 무시됩니다.

password 인자가 지정되지 않고 암호가 필요하면, OpenSSL의 기본 암호 프롬프트 메커니즘을 사용하여 대화식으로 사용자에게 암호를 묻습니다.

개인 키가 인증서와 일치하지 않으면 SSLError가 발생합니다.

버전 3.3에서 변경: 새로운 선택적 인자 password.

SSLContext.load_default_certs(purpose=Purpose.SERVER_AUTH)

Load a set of default “certification authority” (CA) certificates from default locations. On Windows it loads CA certs from the CA and ROOT system stores. On all systems it calls SSLContext.set_default_verify_paths(). In the future the method may load CA certificates from other locations, too.

The purpose flag specifies what kind of CA certificates are loaded. The default settings Purpose.SERVER_AUTH loads certificates, that are flagged and trusted for TLS web server authentication (client side sockets). Purpose.CLIENT_AUTH loads CA certificates for client certificate verification on the server side.

Added in version 3.4.

SSLContext.load_verify_locations(cafile=None, capath=None, cadata=None)

verify_mode가 CERT_NONE가 아닐 때, 다른 피어의 인증서를 확인하는 데 사용되는 “인증 기관” (CA) 인증서 집합을 로드합니다. cafile 나 capath 중 적어도 하나는 지정해야 합니다.

이 메서드는 PEM 이나 DER 형식으로 인증서 해지 목록(CRL)을 로드할 수도 있습니다. CRL을 사용하려면 SSLContext.verify_flags를 올바르게 구성해야 합니다.

cafile 문자열이 있으면 이어붙인 PEM 형식의 CA 인증서 파일 경로입니다. 이 파일에 인증서를 정렬하는 방법에 대한 자세한 내용은 인증서의 논의를 참조하십시오.

The capath string, if present, is the path to a directory containing several CA certificates in PEM format, following an OpenSSL specific layout [https://docs.openssl.org/master/man3/SSL_CTX_load_verify_locations/].

cadata 객체가 있으면, 하나 이상의 PEM-인코딩된 인증서의 ASCII 문자열이거나 DER-인코딩된 인증서의 바이트열류 객체입니다. capath와 마찬가지로 PEM-인코딩된 인증서 주위에 추가한 줄은 무시되지만 적어도 하나의 인증서가 있어야 합니다.

버전 3.4에서 변경: 새로운 선택적 인자 cadata

SSLContext.get_ca_certs(binary_form=False)

로드된 “인증 기관” (CA) 인증서 목록을 가져옵니다. binary_form 매개 변수가 False면 각 리스트 항목은 SSLSocket.getpeercert()의 출력과 같은 딕셔너리입니다. 그렇지 않으면, 이 메서드는 DER-인코딩된 인증서의 리스트를 반환합니다. 반환된 리스트에는 인증서가 SSL 연결이 요청하고 로드되지 않는 한 capath의 인증서가 포함되어 있지 않습니다.

참고

capath 디렉터리의 인증서는 적어도 한 번 이상 사용하지 않으면 로드되지 않습니다.

Added in version 3.4.

SSLContext.get_ciphers()

활성화된 사이퍼의 리스트를 가져옵니다. 리스트는 사이퍼 우선순위 순입니다. SSLContext.set_ciphers()를 참조하십시오.

예제:

>>> ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
>>> ctx.set_ciphers('ECDHE+AESGCM:!ECDSA')
>>> ctx.get_ciphers()
[{'aead': True,
  'alg_bits': 256,
  'auth': 'auth-rsa',
  'description': 'ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  '
                 'Enc=AESGCM(256) Mac=AEAD',
  'digest': None,
  'id': 50380848,
  'kea': 'kx-ecdhe',
  'name': 'ECDHE-RSA-AES256-GCM-SHA384',
  'protocol': 'TLSv1.2',
  'strength_bits': 256,
  'symmetric': 'aes-256-gcm'},
 {'aead': True,
  'alg_bits': 128,
  'auth': 'auth-rsa',
  'description': 'ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  '
                 'Enc=AESGCM(128) Mac=AEAD',
  'digest': None,
  'id': 50380847,
  'kea': 'kx-ecdhe',
  'name': 'ECDHE-RSA-AES128-GCM-SHA256',
  'protocol': 'TLSv1.2',
  'strength_bits': 128,
  'symmetric': 'aes-128-gcm'}]

Added in version 3.6.

SSLContext.set_default_verify_paths()

OpenSSL 라이브러리를 빌드할 때 정의된 파일 시스템 경로에서 기본 “인증 기관” (CA) 인증서 집합을 로드합니다. 불행히도, 이 메서드가 성공하는지를 쉽게 알 방법이 없습니다: 인증서를 찾을 수 없어도 에러가 반환되지 않습니다. 하지만 OpenSSL 라이브러리가 운영 체제 일부로 제공되면 올바르게 구성되었을 가능성이 큽니다.

SSLContext.set_ciphers(ciphers)

Set the available ciphers for sockets created with this context. It should be a string in the OpenSSL cipher list format [https://docs.openssl.org/master/man1/ciphers/]. If no cipher can be selected (because compile-time options or other configuration forbids use of all the specified ciphers), an SSLError will be raised.

참고

연결될 때, SSL 소켓의 SSLSocket.cipher() 메서드가 현재 선택된 사이퍼를 제공합니다.

TLS 1.3 cipher suites cannot be disabled with set_ciphers().

SSLContext.set_alpn_protocols(protocols)

SSL/TLS 핸드 셰이크 중에 소켓이 알려야 하는 프로토콜을 지정합니다. 우선순위에 따라 정렬된 ['http/1.1', 'spdy/2']와 같은 ASCII 문자열 리스트여야 합니다. 프로토콜 선택은 핸드 셰이크 중에 발생하며, RFC 7301 [https://datatracker.ietf.org/doc/html/rfc7301.html]에 따라 처리됩니다. 성공적인 핸드 셰이크가 끝나면, SSLSocket.selected_alpn_protocol() 메서드는 합의된 프로토콜을 반환합니다.

HAS_NPN이 False면, 이 메서드는 NotImplementedError를 발생시킵니다.

Added in version 3.5.

SSLContext.set_npn_protocols(protocols)

SSL/TLS 핸드 셰이크 중에 소켓이 알려야 하는 프로토콜을 지정합니다. 우선순위에 따라 정렬된 ['http/1.1', 'spdy/2']와 같은 문자열 리스트여야 합니다. 프로토콜 선택은 핸드 셰이크 중에 발생하며, Application Layer Protocol Negotiation [https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation]에 따라 처리됩니다. 성공적인 핸드 셰이크가 끝나면, SSLSocket.selected_npn_protocol() 메서드는 합의된 프로토콜을 반환합니다.

HAS_NPN이 False면, 이 메서드는 NotImplementedError를 발생시킵니다.

Added in version 3.3.

버전 3.10부터 폐지됨: NPN has been superseded by ALPN

SSLContext.sni_callback

TLS 클라이언트가 서버 이름 표시를 지정할 때 SSL/TLS 서버에서 TLS 클라이언트 Hello 핸드 셰이크 메시지를 받은 후 호출될 콜백 함수를 등록합니다. 서버 이름 표시 메커니즘은 RFC 6066 [https://datatracker.ietf.org/doc/html/rfc6066.html] section 3 - Server Name Indication에서 지정됩니다.

SSLContext 당 하나의 콜백 만 설정할 수 있습니다. sni_callback이 None으로 설정되면 콜백이 비활성화됩니다. 이 함수를 호출하면 이전에 등록된 콜백이 비활성화됩니다.

콜백 함수는 세 개의 인자로 호출됩니다. 첫 번째는 ssl.SSLSocket이고, 두 번째는 클라이언트가 통신하려는 서버 이름을 나타내는 문자열(또는 TLS 클라이언트 Hello에 서버 이름이 없으면 None)이며, 세 번째 인자는 원래 SSLContext입니다. 서버 이름 인자는 텍스트입니다. 국제화된 도메인 이름의 경우, 서버 이름은 IDN A-레이블("xn--pythn-mua.org")입니다.

이 콜백은 일반적으로 ssl.SSLSocket의 SSLSocket.context 어트리뷰트를 서버 이름과 일치하는 인증서 체인을 나타내는 SSLContext 형의 새 객체로 변경하는 데 사용됩니다.

Due to the early negotiation phase of the TLS connection, only limited methods and attributes are usable like SSLSocket.selected_alpn_protocol() and SSLSocket.context. The SSLSocket.getpeercert(), SSLSocket.get_verified_chain(), SSLSocket.get_unverified_chain() SSLSocket.cipher() and SSLSocket.compression() methods require that the TLS connection has progressed beyond the TLS Client Hello and therefore will not return meaningful values nor can they be called safely.

TLS 협상을 계속하려면 sni_callback 함수가 None을 반환해야 합니다. TLS 실패가 필요하면, 상수 ALERT_DESCRIPTION_*를 반환할 수 있습니다. 다른 반환 값은 ALERT_DESCRIPTION_INTERNAL_ERROR로 TLS 치명적인 에러를 발생시킵니다.

sni_callback 함수에서 예외가 발생하면, TLS 연결이 치명적인 TLS 경고 메시지 ALERT_DESCRIPTION_HANDSHAKE_FAILURE로 종료됩니다.

이 메서드는 OpenSSL 라이브러리가 빌드될 때 OPENSSL_NO_TLSEXT가 정의되었으면 NotImplementedError를 발생시킵니다.

Added in version 3.7.

SSLContext.set_servername_callback(server_name_callback)

이전 버전과의 호환성을 위해 유지되는 기존 API입니다. 가능하면, 대신 sni_callback을 사용해야 합니다. 주어진 server_name_callback은 sni_callback과 비슷하지만, 서버 호스트 이름이 IDN-인코딩된 국제화된 도메인 이름일 때 server_name_callback은 디코딩된 U-레이블("pythön.org")을 받습니다.

If there is a decoding error on the server name, the TLS connection will terminate with an ALERT_DESCRIPTION_INTERNAL_ERROR fatal TLS alert message to the client.

Added in version 3.4.

SSLContext.load_dh_params(dhfile)

Diffie-Hellman (DH) 키 교환을 위한 키 생성 매개 변수를 로드합니다. DH 키 교환을 사용하면 계산 자원(서버와 클라이언트 모두)을 희생하여 FS(forward secrecy)를 향상합니다. dhfile 매개 변수는 PEM 형식의 DH 매개 변수를 포함하는 파일의 경로여야 합니다.

이 설정은 클라이언트 소켓에는 적용되지 않습니다. OP_SINGLE_DH_USE 옵션을 사용하여 보안을 더 향상할 수도 있습니다.

Added in version 3.3.

SSLContext.set_ecdh_curve(curve_name)

타원 곡선(Elliptic Curve) 기반 Diffie-Hellman (ECDH) 키 교환을 위한 곡선 이름을 설정합니다. 보안성에 대한 논란의 여지는 있지만 ECDH는 일반 DH보다 상당히 빠릅니다. curve_name 매개 변수는 잘 알려진 타원 곡선을 설명하는 문자열이어야 합니다, 예를 들어, 널리 지원되는 곡선인 prime256v1.

이 설정은 클라이언트 소켓에는 적용되지 않습니다. OP_SINGLE_ECDH_USE 옵션을 사용하여 보안을 더 향상할 수도 있습니다.

HAS_ECDH가 False면 이 메서드를 사용할 수 없습니다.

Added in version 3.3.

더 보기

SSL/TLS & Perfect Forward Secrecy [https://vincent.bernat.ch/en/blog/2011-ssl-perfect-forward-secrecy]

Vincent Bernat.

SSLContext.wrap_socket(sock, server_side=False, do_handshake_on_connect=True, suppress_ragged_eofs=True, server_hostname=None, session=None)

Wrap an existing Python socket sock and return an instance of SSLContext.sslsocket_class (default SSLSocket). The returned SSL socket is tied to the context, its settings and certificates. sock must be a SOCK_STREAM socket; other socket types are unsupported.

매개 변수 server_side는 서버 측과 클라이언트 측 동작 중 어느 것이 소켓에서 필요한지를 식별하는 논릿값입니다.

클라이언트 측 소켓의 경우, 컨텍스트 구성이 지연됩니다; 하부 소켓이 아직 연결되어 있지 않으면, connect()가 소켓에서 호출된 후 컨텍스트 생성이 수행됩니다. 서버 측 소켓의 경우, 소켓에 원격 피어가 없으면, 리스닝 소켓이라고 가정하고, 서버 측 SSL 감싸기는 accept() 메서드를 통해 받아들인 클라이언트 연결에 대해 자동으로 수행됩니다. 메서드는 SSLError를 발생시킬 수 있습니다.

클라이언트 연결에서, 선택적 매개 변수 server_hostname는 연결하려는 서비스의 호스트 이름을 지정합니다. 이를 통해 단일 서버는 HTTP 가상 호스트와 매우 흡사하게 서로 다른 인증서로 여러 SSL 기반 서비스를 호스팅 할 수 있습니다. server_side가 참일 때 server_hostname를 지정하면 ValueError가 발생합니다.

매개 변수 do_handshake_on_connect는 socket.connect()를 수행한 후 SSL 핸드 셰이크를 자동으로 수행할지, 또는 응용 프로그램이 SSLSocket.do_handshake() 메서드를 호출하여 명시적으로 호출할지를 지정합니다. SSLSocket.do_handshake()를 명시적으로 호출하면, 핸드 셰이크에 수반되는 소켓 I/O의 블로킹 동작을 프로그램에서 제어할 수 있습니다.

매개 변수 suppress_ragged_eofs는 SSLSocket.recv() 메서드가 연결의 다른 끝으로부터의 예기치 않은 EOF를 알리는 방법을 지정합니다. True(기본값)로 지정되면, 하부 소켓에서 발생한 예기치 않은 EOF 에러에 대한 응답으로 정상 EOF(빈 바이트열 객체)를 반환합니다. False면 예외를 호출자에게 다시 발생시킵니다.

session, session을 참조하십시오.

To wrap an SSLSocket in another SSLSocket, use SSLContext.wrap_bio().

버전 3.5에서 변경: OpenSSL에 SNI가 없더라도 항상 server_hostname을 전달할 수 있습니다.

버전 3.6에서 변경: session 인자가 추가되었습니다.

버전 3.7에서 변경: The method returns an instance of SSLContext.sslsocket_class instead of hard-coded SSLSocket.

SSLContext.sslsocket_class

SSLContext.wrap_socket()의 반환형, 기본값은 SSLSocket입니다. 이 어트리뷰트는 SSLSocket의 사용자 정의 서브 클래스를 반환하기 위해 클래스의 인스턴스에서 재정의될 수 있습니다.

Added in version 3.7.

SSLContext.wrap_bio(incoming, outgoing, server_side=False, server_hostname=None, session=None)

BIO 객체 incoming 과 outgoing을 감싸고 SSLContext.sslobject_class(기본값 SSLObject)의 인스턴스를 반환합니다. SSL 루틴은 incoming BIO에서 입력 데이터를 읽고 outgoing BIO에 데이터를 씁니다.

server_side, server_hostname 및 session 매개 변수는 SSLContext.wrap_socket()에서와 같은 의미입니다.

버전 3.6에서 변경: session 인자가 추가되었습니다.

버전 3.7에서 변경: The method returns an instance of SSLContext.sslobject_class instead of hard-coded SSLObject.

SSLContext.sslobject_class

SSLContext.wrap_bio()의 반환형, 기본값은 SSLObject입니다. 이 어트리뷰트는 SSLObject의 사용자 정의 서브 클래스를 반환하기 위해 클래스의 인스턴스에서 재정의될 수 있습니다.

Added in version 3.7.

SSLContext.session_stats()

Get statistics about the SSL sessions created or managed by this context. A dictionary is returned which maps the names of each piece of information [https://docs.openssl.org/1.1.1/man3/SSL_CTX_sess_number/] to their numeric values. For example, here is the total number of hits and misses in the session cache since the context was created:

>>> stats = context.session_stats()
>>> stats['hits'], stats['misses']
(0, 0)

SSLContext.check_hostname

SSLSocket.do_handshake()에서 피어 인증서의 호스트 이름을 일치시킬지 여부. 컨텍스트의 verify_mode는 CERT_OPTIONAL나 CERT_REQUIRED로 설정되어야 하며, 호스트 이름을 일치시키려면 server_hostname을 wrap_socket()로 전달해야 합니다. 호스트 이름 확인을 활성화하면 verify_mode가 CERT_NONE에서 CERT_REQUIRED로 자동 설정됩니다. 호스트 이름 검사가 활성화되어 있으면 CERT_NONE로 다시 설정할 수 없습니다. PROTOCOL_TLS_CLIENT 프로토콜은 기본적으로 호스트 이름 확인을 활성화합니다. 다른 프로토콜의 경우, 호스트 이름 확인을 명시적으로 활성화해야 합니다.

예제:

import socket, ssl

context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
context.verify_mode = ssl.CERT_REQUIRED
context.check_hostname = True
context.load_default_certs()

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ssl_sock = context.wrap_socket(s, server_hostname='www.verisign.com')
ssl_sock.connect(('www.verisign.com', 443))

Added in version 3.4.

버전 3.7에서 변경: 호스트 이름 검사가 활성화되고 verify_mode가 CERT_NONE이면 이제 verify_mode가 CERT_REQUIRED로 자동 변경됩니다. 이전에는 같은 작업이 ValueError로 실패했을 것입니다.

SSLContext.keylog_filename

키 자료가 생성되거나 수신될 때마다, TLS 키를 키로그(keylog) 파일에 기록합니다. 키로그 파일은 디버깅 목적으로만 설계되었습니다. 파일 형식은 NSS에 의해 지정되었고 Wireshark과 같은 많은 트래픽 분석기에서 사용됩니다. 로그 파일은 덧붙이기 전용 모드로 열립니다. 쓰기는 스레드 간에 동기화되지만, 프로세스 간에는 동기화되지 않습니다.

Added in version 3.8.

SSLContext.maximum_version

지원되는 가장 높은 TLS 버전을 나타내는 TLSVersion 열거형 멤버. 기본값은 TLSVersion.MAXIMUM_SUPPORTED입니다. 어트리뷰트는 PROTOCOL_TLS, PROTOCOL_TLS_CLIENT 및 PROTOCOL_TLS_SERVER 이외의 프로토콜에 대해 읽기 전용입니다.

어트리뷰트 maximum_version, minimum_version 및 SSLContext.options는 모두 컨텍스트의 지원되는 SSL과 TLS 버전에 영향을 줍니다. 구현은 부적합한 조합을 방지하지 못합니다. 예를 들어, options에 OP_NO_TLSv1_2가 있고 maximum_version이 TLSVersion.TLSv1_2로 설정된 컨텍스트는 TLS 1.2 연결을 이룰 수 없습니다.

Added in version 3.7.

SSLContext.minimum_version

가장 낮은 지원 버전 또는 TLSVersion.MINIMUM_SUPPORTED이라는 것만 제외하면 SSLContext.maximum_version과 같습니다.

Added in version 3.7.

SSLContext.num_tickets

Control the number of TLS 1.3 session tickets of a PROTOCOL_TLS_SERVER context. The setting has no impact on TLS 1.0 to 1.2 connections.

Added in version 3.8.

SSLContext.options

이 컨텍스트에서 활성화된 SSL 옵션 집합을 나타내는 정수. 기본값은 OP_ALL이지만, OP_NO_SSLv2와 같은 다른 옵션을 함께 OR로 연결하여 지정할 수 있습니다.

버전 3.6에서 변경: SSLContext.options는 Options 플래그를 반환합니다.:

>>> ssl.create_default_context().options
<Options.OP_ALL|OP_NO_SSLv3|OP_NO_SSLv2|OP_NO_COMPRESSION: 2197947391>

버전 3.7부터 폐지됨: All OP_NO_SSL* and OP_NO_TLS* options have been deprecated since Python 3.7. Use SSLContext.minimum_version and SSLContext.maximum_version instead.

SSLContext.post_handshake_auth

TLS 1.3 포스트 핸드 셰이크 클라이언트 인증을 사용합니다. 포스트 핸드 셰이크 인증은 기본적으로 사용되지 않으며 서버는 초기 핸드 셰이크 중에 TLS 클라이언트 인증서만 요청할 수 있습니다. 활성화되면, 서버는 핸드 셰이크 후에 언제든지 TLS 클라이언트 인증서를 요청할 수 있습니다.

클라이언트 측 소켓에서 활성화될 때, 클라이언트는 포스트 핸드 셰이크 인증을 지원하는 서버에 신호를 보냅니다.

서버 측 소켓에서 활성화될 때, SSLContext.verify_mode도 CERT_OPTIONAL이나 CERT_REQUIRED로 설정해야 합니다. 실제 클라이언트 인증서 교환은 SSLSocket.verify_client_post_handshake()가 호출되고 일부 I/O가 수행될 때까지 지연됩니다.

Added in version 3.8.

SSLContext.protocol

컨텍스트를 구성할 때 선택한 프로토콜 버전. 이 어트리뷰트는 읽기 전용입니다.

SSLContext.hostname_checks_common_name

check_hostname가 SAN(subject alternative name) 확장이 없을 때 인증서의 SCN(subject common name)을 유효성 검사하는 것으로 폴백 할지 아닐지 (기본값: 참)

Added in version 3.7.

버전 3.10에서 변경: The flag had no effect with OpenSSL before version 1.1.1l. Python 3.8.9, 3.9.3, and 3.10 include workarounds for previous versions.

SSLContext.security_level

An integer representing the security level [https://docs.openssl.org/master/man3/SSL_CTX_get_security_level/] for the context. This attribute is read-only.

Added in version 3.10.

SSLContext.verify_flags

The flags for certificate verification operations. You can set flags like VERIFY_CRL_CHECK_LEAF by ORing them together. By default OpenSSL does neither require nor verify certificate revocation lists (CRLs).

Added in version 3.4.

버전 3.6에서 변경: SSLContext.verify_flags는 VerifyFlags 플래그를 반환합니다.:

>>> ssl.create_default_context().verify_flags
<VerifyFlags.VERIFY_X509_TRUSTED_FIRST: 32768>

SSLContext.verify_mode

다른 피어의 인증서를 확인할지와 확인이 실패할 때 어떻게 해야 하는지를 나타냅니다. 이 어트리뷰트는 CERT_NONE, CERT_OPTIONAL 또는 CERT_REQUIRED 중 하나여야 합니다.

버전 3.6에서 변경: SSLContext.verify_mode는 VerifyMode 열거형을 반환합니다.:

>>> ssl.create_default_context().verify_mode
<VerifyMode.CERT_REQUIRED: 2>

SSLContext.set_psk_client_callback(callback)

Enables TLS-PSK (pre-shared key) authentication on a client-side connection.

In general, certificate based authentication should be preferred over this method.

The parameter callback is a callable object with the signature: def callback(hint: str | None) -> tuple[str | None, bytes]. The hint parameter is an optional identity hint sent by the server. The return value is a tuple in the form (client-identity, psk). Client-identity is an optional string which may be used by the server to select a corresponding PSK for the client. The string must be less than or equal to 256 octets when UTF-8 encoded. PSK is a bytes-like object representing the pre-shared key. Return a zero length PSK to reject the connection.

Setting callback to None removes any existing callback.

참고

When using TLS 1.3:

the hint parameter is always None.

client-identity must be a non-empty string.

Example usage:

context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
context.check_hostname = False
context.verify_mode = ssl.CERT_NONE
context.maximum_version = ssl.TLSVersion.TLSv1_2
context.set_ciphers('PSK')

# A simple lambda:
psk = bytes.fromhex('c0ffee')
context.set_psk_client_callback(lambda hint: (None, psk))

# A table using the hint from the server:
psk_table = { 'ServerId_1': bytes.fromhex('c0ffee'),
              'ServerId_2': bytes.fromhex('facade')
}
def callback(hint):
    return 'ClientId_1', psk_table.get(hint, b'')
context.set_psk_client_callback(callback)

This method will raise NotImplementedError if HAS_PSK is False.

Added in version 3.13.

SSLContext.set_psk_server_callback(callback, identity_hint=None)

Enables TLS-PSK (pre-shared key) authentication on a server-side connection.

In general, certificate based authentication should be preferred over this method.

The parameter callback is a callable object with the signature: def callback(identity: str | None) -> bytes. The identity parameter is an optional identity sent by the client which can be used to select a corresponding PSK. The return value is a bytes-like object representing the pre-shared key. Return a zero length PSK to reject the connection.

Setting callback to None removes any existing callback.

The parameter identity_hint is an optional identity hint string sent to the client. The string must be less than or equal to 256 octets when UTF-8 encoded.

참고

When using TLS 1.3 the identity_hint parameter is not sent to the client.

Example usage:

context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
context.maximum_version = ssl.TLSVersion.TLSv1_2
context.set_ciphers('PSK')

# A simple lambda:
psk = bytes.fromhex('c0ffee')
context.set_psk_server_callback(lambda identity: psk)

# A table using the identity of the client:
psk_table = { 'ClientId_1': bytes.fromhex('c0ffee'),
              'ClientId_2': bytes.fromhex('facade')
}
def callback(identity):
    return psk_table.get(identity, b'')
context.set_psk_server_callback(callback, 'ServerId_1')

This method will raise NotImplementedError if HAS_PSK is False.

Added in version 3.13.

인증서

인증서는 일반적으로 공개키/개인키 시스템 일부입니다. 이 시스템에서, 각 주체(principal)(시스템, 사람 또는 조직일 수 있습니다)에게는 고유한 두 부분으로 된 암호화 키가 지정됩니다. 열쇠의 한 부분은 공개(public)며, 공개키(public key)라고 불립니다; 다른 부분은 비밀로 유지되며, 개인키(private key)라고 합니다. 두 부분은 관련이 있습니다. 두 부분 중 하나를 사용하여 메시지를 암호화하면, 다른 부분으로 해독할 수 있고, 오직 다른 부분으로만 해독할 수 있습니다.

인증서에는 두 주체에 대한 정보가 들어 있습니다. 주체(subject)의 이름과 주체의 공개키가 들어 있습니다. 또한 발행자(issuer)라는 두 번째 주체의 진술을 포함하는데, 해당 주체(subject)는 자신이 주장하는 존재며, 실제로 공개키 또한 주체(subject)의 것이 맞는다는 내용입니다. 발행자의 진술은 발행자만이 알고 있는 발행자의 개인키로 서명됩니다. 그러나 누구든지 발행자의 공개키를 찾고 이를 사용하여 진술을 해독하고 인증서의 다른 정보와 비교함으로써 발행자의 진술을 확인할 수 있습니다. 또한, 인증서에는 유효 기간에 대한 정보가 들어 있습니다. 이것은 “notBefore”와 “notAfter”라고 하는 두 개의 필드로 표현됩니다.

파이썬에서 인증서를 사용할 때, 클라이언트나 서버는 인증서를 사용하여 자신이 누구인지 증명할 수 있습니다. 네트워크 연결의 다른 쪽은 인증서 생성을 요구받을 수도 있으며, 해당 인증서는 이러한 유효성 검사가 필요한 클라이언트나 서버를 만족하도록 유효성을 검사할 수 있습니다. 유효성 검증이 실패하면 연결 시도가 예외를 발생시키도록 설정할 수 있습니다. 유효성 검사는 하부 OpenSSL 프레임워크에 의해 자동으로 수행됩니다; 응용 프로그램은 그 메커니즘에 관심을 두지 않아도 됩니다. 그러나 응용 프로그램은 일반적으로 이 절차를 수행할 수 있도록 인증서 집합을 제공해야 합니다.

파이썬은 인증서를 포함하기 위해 파일을 사용합니다. 그들은 “PEM”(RFC 1422 [https://datatracker.ietf.org/doc/html/rfc1422.html]를 참조하세요)으로 포맷해야 합니다. 머릿줄과 꼬리 줄로 감싼 base-64 로 인코딩된 형식입니다:

-----BEGIN CERTIFICATE-----
... (certificate in base64 PEM encoding) ...
-----END CERTIFICATE-----

인증서 체인

인증서를 포함하는 파이썬 파일에는 인증서 시퀀스가 포함될 수 있는데, 때로 인증서 체인(*certificate chain)이라고 부릅니다. 이 체인은 클라이언트 또는 서버 “당사자” 주체에 대한 특정 인증서로 시작해야 하며, 그다음에 그 인증서의 발행자에 대한 인증서가 오고, 그다음에 직전 인증서 발행자에 대한 인증서가 오는 식으로 이어지다가, 결국에는 자체 서명(self-signed) 인증서를 얻게 되는데, 주체와 발행자가 같은 인증서로 때로 루트 인증서라고도 부릅니다. 인증서는 인증서 파일에 함께 이어붙여야 합니다. 예를 들어, 서버 인증서에서 서버 인증서에 서명한 인증 기관의 인증서를 거쳐 인증 기관의 인증서를 발행한 기관의 루트 인증서에 이르는 세 개의 인증서 체인이 있다고 가정합시다:

-----BEGIN CERTIFICATE-----
... (certificate for your server)...
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
... (the certificate for the CA)...
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
... (the root certificate for the CA's issuer)...
-----END CERTIFICATE-----

CA 인증서

연결의 반대편의 인증서의 유효성 검사가 필요하면, 신뢰할 수 있는 각 발행자의 인증서 체인으로 채워진 “CA 인증서” 파일을 제공해야 합니다. 다시 말하지만, 이 파일은 단지 이러한 체인들을 함께 이어붙인 것입니다. 유효성 검사를 위해, 파이썬은 일치하는 파일에서 찾은 첫 번째 체인을 사용합니다. 플랫폼의 인증서 파일은 SSLContext.load_default_certs()를 호출하여 사용할 수 있습니다, 이는 create_default_context()로 자동으로 수행됩니다.

결합한 키와 인증서

Often the private key is stored in the same file as the certificate; in this case, only the certfile parameter to SSLContext.load_cert_chain() needs to be passed. If the private key is stored with the certificate, it should come before the first certificate in the certificate chain:

-----BEGIN RSA PRIVATE KEY-----
... (private key in base64 encoding) ...
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
... (certificate in base64 PEM encoding) ...
-----END CERTIFICATE-----

자체 서명 인증서

SSL-암호화된 연결 서비스를 제공하는 서버를 만들려면, 해당 서비스에 대한 인증서를 얻어야 합니다. 인증 기관에서 사는 등 다양한 방법으로 적절한 인증서를 얻을 수 있습니다. 또 다른 일반적인 관행은 자체 서명 인증서를 생성하는 것입니다. 이렇게 하는 가장 간단한 방법은 OpenSSL 패키지에서 다음과 같은 방법을 사용하는 것입니다:

% openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout cert.pem
Generating a 1024 bit RSA private key
.......++++++
.............................++++++
writing new private key to 'cert.pem'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:MyState
Locality Name (eg, city) []:Some City
Organization Name (eg, company) [Internet Widgits Pty Ltd]:My Organization, Inc.
Organizational Unit Name (eg, section) []:My Group
Common Name (eg, YOUR name) []:myserver.mygroup.myorganization.com
Email Address []:ops@myserver.mygroup.myorganization.com
%

자체 서명 인증서의 단점은 그 자신이 루트 인증서이고, 아무도 그들의 알려진(그리고 신뢰할 수 있는) 루트 인증서의 캐시에 이 인증서를 갖고 있지 않다는 것입니다.

예제

SSL 지원 검사하기

파이썬 설치에 SSL 지원이 있는지를 검사하려면, 사용자 코드는 다음과 같은 관용구를 사용해야 합니다:

try:
    import ssl
except ImportError:
    pass
else:
    ...  # do something that requires SSL support

클라이언트 측 연산

이 예제는 자동 인증서 확인을 포함하여 클라이언트 소켓에 대해 권장되는 보안 설정을 사용하여 SSL 컨텍스트를 만듭니다:

>>> context = ssl.create_default_context()

보안 설정을 직접 조정하려면, 처음부터 컨텍스트를 만들 수 있습니다 (그러나 올바른 설정을 얻지 못할 수도 있습니다):

>>> context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
>>> context.load_verify_locations("/etc/ssl/certs/ca-bundle.crt")

(이 코드 조각은 운영 체제가 모든 CA 인증서 번들을 /etc/ssl/certs/ca-bundle.crt에 배치한다고 가정합니다; 그렇지 않으면, 에러가 발생하고 위치를 조정해야 합니다)

PROTOCOL_TLS_CLIENT 프로토콜은 인증서 유효성 검사와 호스트 이름 확인을 위한 컨텍스트를 구성합니다. verify_mode는 CERT_REQUIRED로 설정되고 check_hostname는 True로 설정됩니다. 다른 모든 프로토콜은 안전하지 않은 기본값으로 SSL 컨텍스트를 만듭니다.

컨텍스트를 사용하여 서버에 연결할 때, CERT_REQUIRED와 check_hostname은 서버 인증서의 유효성을 검사합니다: 서버 인증서가 CA 인증서 중 하나를 사용하여 서명되었는지 확인하고, 서명의 정확성을 검사하고, 호스트 이름의 유효성과 아이덴티티와 같은 다른 속성을 확인합니다:

>>> conn = context.wrap_socket(socket.socket(socket.AF_INET),
...                            server_hostname="www.python.org")
>>> conn.connect(("www.python.org", 443))

그런 다음 인증서를 가져올 수 있습니다:

>>> cert = conn.getpeercert()

시각적인 검사는 인증서가 원하는 서비스(즉, HTTPS 호스트 www.python.org)를 식별함을 보여줍니다:

>>> pprint.pprint(cert)
{'OCSP': ('http://ocsp.digicert.com',),
 'caIssuers': ('http://cacerts.digicert.com/DigiCertSHA2ExtendedValidationServerCA.crt',),
 'crlDistributionPoints': ('http://crl3.digicert.com/sha2-ev-server-g1.crl',
                           'http://crl4.digicert.com/sha2-ev-server-g1.crl'),
 'issuer': ((('countryName', 'US'),),
            (('organizationName', 'DigiCert Inc'),),
            (('organizationalUnitName', 'www.digicert.com'),),
            (('commonName', 'DigiCert SHA2 Extended Validation Server CA'),)),
 'notAfter': 'Sep  9 12:00:00 2016 GMT',
 'notBefore': 'Sep  5 00:00:00 2014 GMT',
 'serialNumber': '01BB6F00122B177F36CAB49CEA8B6B26',
 'subject': ((('businessCategory', 'Private Organization'),),
             (('1.3.6.1.4.1.311.60.2.1.3', 'US'),),
             (('1.3.6.1.4.1.311.60.2.1.2', 'Delaware'),),
             (('serialNumber', '3359300'),),
             (('streetAddress', '16 Allen Rd'),),
             (('postalCode', '03894-4801'),),
             (('countryName', 'US'),),
             (('stateOrProvinceName', 'NH'),),
             (('localityName', 'Wolfeboro'),),
             (('organizationName', 'Python Software Foundation'),),
             (('commonName', 'www.python.org'),)),
 'subjectAltName': (('DNS', 'www.python.org'),
                    ('DNS', 'python.org'),
                    ('DNS', 'pypi.org'),
                    ('DNS', 'docs.python.org'),
                    ('DNS', 'testpypi.org'),
                    ('DNS', 'bugs.python.org'),
                    ('DNS', 'wiki.python.org'),
                    ('DNS', 'hg.python.org'),
                    ('DNS', 'mail.python.org'),
                    ('DNS', 'packaging.python.org'),
                    ('DNS', 'pythonhosted.org'),
                    ('DNS', 'www.pythonhosted.org'),
                    ('DNS', 'test.pythonhosted.org'),
                    ('DNS', 'us.pycon.org'),
                    ('DNS', 'id.python.org')),
 'version': 3}

이제 SSL 채널이 설정되고 인증서가 확인되었습니다, 서버와 대화할 수 있습니다:

>>> conn.sendall(b"HEAD / HTTP/1.0\r\nHost: linuxfr.org\r\n\r\n")
>>> pprint.pprint(conn.recv(1024).split(b"\r\n"))
[b'HTTP/1.1 200 OK',
 b'Date: Sat, 18 Oct 2014 18:27:20 GMT',
 b'Server: nginx',
 b'Content-Type: text/html; charset=utf-8',
 b'X-Frame-Options: SAMEORIGIN',
 b'Content-Length: 45679',
 b'Accept-Ranges: bytes',
 b'Via: 1.1 varnish',
 b'Age: 2188',
 b'X-Served-By: cache-lcy1134-LCY',
 b'X-Cache: HIT',
 b'X-Cache-Hits: 11',
 b'Vary: Cookie',
 b'Strict-Transport-Security: max-age=63072000; includeSubDomains',
 b'Connection: close',
 b'',
 b'']

아래의 보안 고려 사항의 논의를 참조하십시오.

서버 측 연산

서버 연산의 경우, 일반적으로 서버 인증서와 개인 키가 각각 파일에 있어야 합니다. 먼저 클라이언트가 여러분의 신원을 확인할 수 있도록 키와 인증서가 있는 컨텍스트를 만듭니다. 그런 다음 소켓을 열고, 포트에 바인드 하고, listen()을 호출한 다음 클라이언트가 연결하기를 기다립니다:

import socket, ssl

context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
context.load_cert_chain(certfile="mycertfile", keyfile="mykeyfile")

bindsocket = socket.socket()
bindsocket.bind(('myaddr.example.com', 10023))
bindsocket.listen(5)

클라이언트가 연결하면, 소켓에서 accept()를 호출하여 다른 쪽 끝과 연결된 새 소켓을 얻고, 컨텍스트의 SSLContext.wrap_socket() 메서드를 사용하여 연결을 위한 서버 측 SSL 소켓을 만듭니다.:

while True:
    newsocket, fromaddr = bindsocket.accept()
    connstream = context.wrap_socket(newsocket, server_side=True)
    try:
        deal_with_client(connstream)
    finally:
        connstream.shutdown(socket.SHUT_RDWR)
        connstream.close()

그런 다음 connstream에서 데이터를 읽고 클라이언트와 작업을 마칠 때까지 (또는 클라이언트가 마칠 때까지) 뭔가 합니다:

def deal_with_client(connstream):
    data = connstream.recv(1024)
    # empty data means the client is finished with us
    while data:
        if not do_something(connstream, data):
            # we'll assume do_something returns False
            # when we're finished with client
            break
        data = connstream.recv(1024)
    # finished with client

그리고는 새로운 클라이언트 연결을 리스닝하는 것으로 돌아갑니다 (물론, 실제 서버는 별도의 스레드에서 각 클라이언트 연결을 처리하거나 소켓을 비 블로킹 모드로 만들고 이벤트 루프를 사용합니다).

비 블로킹 소켓에 대한 참고 사항

SSL 소켓은 비 블로킹 모드에서 일반 소켓과 약간 다르게 작동합니다. 비 블로킹 소켓으로 작업할 때 주의해야 할 몇 가지 사항이 있습니다:

대부분 SSLSocket 메서드는 I/O 연산이 블록하려고 할 때 BlockingIOError 대신 SSLWantWriteError 나 SSLWantReadError를 발생시킵니다. 하부 소켓에서의 읽기 연산이 필요하면 SSLWantReadError가 발생하고, 하부 소켓에서의 쓰기 연산이 필요하면 SSLWantWriteError가 발생합니다. SSL 소켓에 대한 쓰기 시도는 우선 하부 소켓에서 읽기가 필요할 수 있으며, SSL 소켓에서 읽기를 시도하면 하부 소켓에서 선행 쓰기가 필요할 수 있습니다.

버전 3.5에서 변경: 이전 파이썬 버전에서는, SSLSocket.send() 메서드가 SSLWantWriteError 나 SSLWantReadError를 발생시키는 대신 0을 반환했습니다.

select()를 호출하면 OS-수준 소켓을 읽을 수 있음을 (또는 쓸 수 있음을) 알려줄 수 있습니다만, 이것이 상위 SSL 계층에 충분한 데이터가 있음을 의미하지는 않습니다. 예를 들어, SSL 프레임의 일부만 도착했을 수 있습니다. 따라서, SSLSocket.recv() 와 SSLSocket.send() 실패를 처리할 준비가 되어 있어야 하며, select()를 다시 호출한 후 재시도해야 합니다.

반대로, SSL 계층에는 자체 프레임이 있으므로, SSL 소켓에는 select()가 인식하지 못하더라도 읽을 수 있는 데이터가 있을 수 있습니다. 따라서, 먼저 SSLSocket.recv()를 호출하여 잠재적으로 사용 가능한 모든 데이터를 꺼낸 다음, 여전히 필요할 때만 select() 호출에 블록해야 합니다.

(물론, poll() 이나 selectors 모듈에 있는 것과 같은 다른 프리미티브를 사용할 때도 비슷한 조항이 적용됩니다)

SSL 핸드 셰이크 자체는 비 블로킹입니다: SSLSocket.do_handshake() 메서드는 성공적으로 반환될 때까지 재시도해야 합니다. 다음은 select()를 사용하여 소켓의 준비 상태를 기다리는 개요입니다:

while True:
    try:
        sock.do_handshake()
        break
    except ssl.SSLWantReadError:
        select.select([sock], [], [])
    except ssl.SSLWantWriteError:
        select.select([], [sock], [])

더 보기

asyncio 모듈은 비 블로킹 SSL 소켓을 지원하며 더 고수준의 API를 제공합니다. selectors 모듈을 사용하여 이벤트를 폴링 하고 SSLWantWriteError, SSLWantReadError 및 BlockingIOError 예외를 처리합니다. SSL 핸드 셰이크도 비동기적으로 실행됩니다.

메모리 BIO 지원

Added in version 3.5.

SSL 모듈이 파이썬 2.6에서 소개된 이래로, SSLSocket 클래스는 관련성이 있지만, 별개의 두 기능 영역을 제공했습니다:

SSL 프로토콜 처리

네트워크 IO

네트워크 IO API는 socket.socket가 제공하는 것과 같으며, SSLSocket는 그 것을 상속합니다. 이렇게해서 SSL 소켓을 일반 소켓의 드롭 인 대체품으로 사용할 수 있으므로, 기존 응용 프로그램에 SSL 지원을 쉽게 추가 할 수 있습니다.

SSL 프로토콜 처리와 네트워크 IO의 결합은 일반적으로 잘 작동하지만, 그렇지 않은 경우도 있습니다. socket.socket 과 내부 OpenSSL 소켓 IO 루틴이 가정하는 “파일 기술자에 대한 select/poll” (준비 상태 기반) 모델과 다른 IO 멀티플렉싱 모델을 사용하려는 비동기 IO 프레임워크가 그 예입니다. 이것은 주로 이 모델이 효율적이지 않은 윈도우와 같은 플랫폼과 관련이 있습니다. 이를 위해, SSLObject라는 SSLSocket의 축소된 범위 변형이 제공됩니다.

class ssl.SSLObject

네트워크 IO 메서드를 포함하지 않는 SSL 프로토콜 인스턴스를 나타내는 SSLSocket의 축소 범위 변형입니다. 이 클래스는 일반적으로 메모리 버퍼를 통해 SSL 용 비동기 IO를 구현하려는 프레임워크 작성자가 사용합니다.

이 클래스는 OpenSSL에 의해 구현된 저수준 SSL 객체 위에 인터페이스를 구현합니다. 이 객체는 SSL 연결의 상태를 캡처하지만, 네트워크 IO 자체를 제공하지는 않습니다. IO는 OpenSSL의 IO 추상화 계층인 별도의 “BIO” 객체를 통해 수행되어야 합니다.

이 클래스에는 공개된 생성자가 없습니다. SSLObject 인스턴스는 wrap_bio() 메서드를 사용해서 만들어야 합니다. 이 메서드는 SSLObject 인스턴스를 생성하고 BIO 쌍에 연결합니다. incoming BIO는 파이썬에서 SSL 프로토콜 인스턴스로 데이터를 전달하는 데 사용되는 반면, outgoing BIO는 반대 방향으로 데이터를 전달하는 데 사용됩니다.

다음 메서드를 사용할 수 있습니다:

context

server_side

server_hostname

session

session_reused

read()

write()

getpeercert()

get_verified_chain()

get_unverified_chain()

selected_alpn_protocol()

selected_npn_protocol()

cipher()

shared_ciphers()

compression()

pending()

do_handshake()

verify_client_post_handshake()

unwrap()

get_channel_binding()

version()

SSLSocket와 비교할 때, 이 객체에는 다음과 같은 기능이 없습니다:

모든 형태의 네트워크 IO; recv() 와 send()는 하부 MemoryBIO 버퍼만 읽고 씁니다.

do_handshake_on_connect 기작이 없습니다. 핸드 셰이크를 시작하려면 항상 do_handshake()를 수동으로 호출해야 합니다.

suppress_ragged_eofs는 처리되지 않습니다. 프로토콜을 위반하는 모든 파일 끝(end-of-file) 조건은 SSLEOFError 예외를 통해 보고됩니다.

메서드 unwrap() 호출은 하부 소켓을 반환하는 SSL 소켓과 달리 아무것도 반환하지 않습니다.

SSLContext.set_servername_callback()에 전달된 server_name_callback 콜백은 첫 번째 매개 변수로 SSLSocket 인스턴스 대신 SSLObject 인스턴스를 받습니다.

SSLObject 사용과 관련된 몇 가지 참고 사항:

SSLObject의 모든 IO는 비 블로킹입니다. 이것은 예를 들어 read()는 incoming BIO에 있는 것보다 많은 데이터가 필요하면 SSLWantReadError를 발생시킨다는 것을 의미합니다.

버전 3.7에서 변경: SSLObject instances must be created with wrap_bio(). In earlier versions, it was possible to create instances directly. This was never documented or officially supported.

SSLObject는 메모리 버퍼를 사용하여 바깥세상과 통신합니다. MemoryBIO 클래스는 이 목적으로 사용할 수 있는 메모리 버퍼를 제공합니다. OpenSSL 메모리 BIO (Basic IO) 객체를 감쌉니다:

class ssl.MemoryBIO

파이썬과 SSL 프로토콜 인스턴스 간에 데이터를 전달하는 데 사용할 수 있는 메모리 버퍼.

pending

현재 메모리 버퍼에 있는 바이트의 수를 반환합니다.

eof

메모리 BIO가 현재 EOF(end-of-file) 위치에 있는지를 나타내는 논릿값입니다.

read(n=-1)

메모리 버퍼에서 최대 n 바이트를 읽습니다. n이 지정되지 않았거나 음수면, 모든 바이트가 반환됩니다.

write(buf)

buf의 바이트를 메모리 BIO에 씁니다. buf 인자는 버퍼 프로토콜을 지원하는 객체여야 합니다.

반환 값은 기록된 바이트 수인데, 항상 buf의 길이와 같습니다.

write_eof()

EOF 마커를 메모리 BIO에 씁니다. 이 메서드가 호출된 후, write()를 호출하는 것은 불법입니다. eof 어트리뷰트는 현재 버퍼에 있는 모든 데이터를 읽은 후에 참이 됩니다.

SSL 세션

Added in version 3.6.

class ssl.SSLSession

session에서 사용되는 세션 객체.

id

time

timeout

ticket_lifetime_hint

has_ticket

보안 고려 사항

가장 좋은 기본값

클라이언트의 경우, 보안 정책에 대한 특별한 요구 사항이 없으면, create_default_context() 함수를 사용하여 SSL 컨텍스트를 만드는 것이 좋습니다. 시스템의 신뢰할 수 있는 CA 인증서를 로드하고, 인증서 유효성 검사와 호스트 이름 검사를 활성화하고, 합리적으로 안전한 프로토콜과 사이퍼 설정을 선택합니다.

예를 들어, 다음은 smtplib.SMTP 클래스를 사용하여 SMTP 서버에 대한 신뢰할 수 있고 안전한 연결을 만드는 방법입니다:

>>> import ssl, smtplib
>>> smtp = smtplib.SMTP("mail.python.org", port=587)
>>> context = ssl.create_default_context()
>>> smtp.starttls(context=context)
(220, b'2.0.0 Ready to start TLS')

연결에 클라이언트 인증서가 필요하면, SSLContext.load_cert_chain()으로 추가할 수 있습니다.

대조적으로, SSLContext 생성자를 직접 호출하여 SSL 컨텍스트를 만들면, 기본적으로 인증서 유효성 검사나 호스트 이름 확인이 활성화되지 않습니다. 그렇게 하면, 아래 단락을 읽고 적절한 보안 수준을 달성하십시오.

수동 설정

인증서 확인

When calling the SSLContext constructor directly, CERT_NONE is the default. Since it does not authenticate the other peer, it can be insecure, especially in client mode where most of the time you would like to ensure the authenticity of the server you’re talking to. Therefore, when in client mode, it is highly recommended to use CERT_REQUIRED. However, it is in itself not sufficient; you also have to check that the server certificate, which can be obtained by calling SSLSocket.getpeercert(), matches the desired service. For many protocols and applications, the service can be identified by the hostname. This common check is automatically performed when SSLContext.check_hostname is enabled.

버전 3.7에서 변경: 이제 호스트 이름 일치가 OpenSSL에 의해 수행됩니다. 파이썬은 더는 match_hostname()을 사용하지 않습니다.

서버 모드에서, (고수준 인증 메커니즘을 사용하는 대신) SSL 계층을 사용하여 클라이언트를 인증하려면, CERT_REQUIRED를 지정하고 클라이언트 인증서도 비슷하게 확인해야 합니다.

프로토콜 버전

SSL 버전 2와 3은 안전하지 않은 것으로 간주하므로 사용하기에 위험합니다. 클라이언트와 서버 간에 최대한의 호환성을 원하면 프로토콜 버전으로 PROTOCOL_TLS_CLIENT 나 PROTOCOL_TLS_SERVER를 사용하는 것이 좋습니다. SSLv2 및 SSLv3은 기본적으로 비활성화되어 있습니다.

>>> client_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
>>> client_context.minimum_version = ssl.TLSVersion.TLSv1_3
>>> client_context.maximum_version = ssl.TLSVersion.TLSv1_3

The SSL context created above will only allow TLSv1.3 and later (if supported by your system) connections to a server. PROTOCOL_TLS_CLIENT implies certificate validation and hostname checks by default. You have to load certificates into the context.

사이퍼 선택

If you have advanced security requirements, fine-tuning of the ciphers enabled when negotiating a SSL session is possible through the SSLContext.set_ciphers() method. Starting from Python 3.2.3, the ssl module disables certain weak ciphers by default, but you may want to further restrict the cipher choice. Be sure to read OpenSSL’s documentation about the cipher list format [https://docs.openssl.org/1.1.1/man1/ciphers/#cipher-list-format]. If you want to check which ciphers are enabled by a given cipher list, use SSLContext.get_ciphers() or the openssl ciphers command on your system.

다중 프로세싱

If using this module as part of a multi-processed application (using, for example the multiprocessing or concurrent.futures modules), be aware that OpenSSL’s internal random number generator does not properly handle forked processes. Applications must change the PRNG state of the parent process if they use any SSL feature with os.fork(). Any successful call of RAND_add() or RAND_bytes() is sufficient.

TLS 1.3

Added in version 3.7.

The TLS 1.3 protocol behaves slightly differently than previous version of TLS/SSL. Some new TLS 1.3 features are not yet available.

TLS 1.3은 분리된 사이퍼 스위트 집합을 사용합니다. 모든 AES-GCM과 ChaCha20 사이퍼 스위트는 기본적으로 활성화되어 있습니다. SSLContext.set_ciphers() 메서드는 아직 TLS 1.3 사이퍼를 활성화하거나 비활성화할 수 없지만, SSLContext.get_ciphers()는 이들을 반환합니다.

세션 티켓은 더는 초기 핸드 셰이크의 일부로 전송되지 않고 다르게 처리됩니다. SSLSocket.session 과 SSLSession은 TLS 1.3과 호환되지 않습니다.

클라이언트 측 인증서도 더는 초기 핸드 셰이크 중에 검증되지 않습니다. 서버는 언제든지 인증서를 요청할 수 있습니다. 클라이언트는 서버와 응용 프로그램 데이터를 주고받는 동안 인증서 요청을 처리합니다.

초기 데이터(early data), 지연된 TLS 클라이언트 인증서 요청, 서명 알고리즘 구성 및 rekeying과 같은 TLS 1.3 기능은 아직 지원되지 않습니다.

더 보기

socket.socket 클래스

하부 socket 클래스의 설명서

SSL/TLS Strong Encryption: An Introduction [https://httpd.apache.org/docs/trunk/en/ssl/ssl_intro.html]

Apache HTTP 서버 설명서의 개요

RFC 1422: Privacy Enhancement for Internet Electronic Mail: Part II: Certificate-Based Key Management [https://datatracker.ietf.org/doc/html/rfc1422.html]

Steve Kent

RFC 4086: Randomness Requirements for Security [https://datatracker.ietf.org/doc/html/rfc4086.html]

Donald E., Jeffrey I. Schiller

RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile [https://datatracker.ietf.org/doc/html/rfc5280.html]

D. Cooper

RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2 [https://datatracker.ietf.org/doc/html/rfc5246.html]

T. Dierks et. al.

RFC 6066: Transport Layer Security (TLS) Extensions [https://datatracker.ietf.org/doc/html/rfc6066.html]

D. Eastlake

IANA TLS: Transport Layer Security (TLS) Parameters [https://www.iana.org/assignments/tls-parameters/tls-parameters.xml]

IANA

RFC 7525: Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) [https://datatracker.ietf.org/doc/html/rfc7525.html]

IETF

모질라의 서버 측 TLS 추천 [https://wiki.mozilla.org/Security/Server_Side_TLS]

Mozilla

select — Waiting for I/O completion

This module provides access to the select() and poll() functions available in most operating systems, devpoll() available on Solaris and derivatives, epoll() available on Linux 2.5+ and kqueue() available on most BSD. Note that on Windows, it only works for sockets; on other operating systems, it also works for other file types (in particular, on Unix, it works on pipes). It cannot be used on regular files to determine whether a file has grown since it was last read.

참고

selectors 모듈은 select 모듈 프리미티브에 기반한 고수준의 효율적인 I/O 멀티플렉싱을 제공합니다. 사용되는 OS 수준 프리미티브에 대한 정확한 제어를 원하지 않는 한, 사용자는 selectors 모듈을 대신 사용하는 것이 좋습니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

모듈은 다음을 정의합니다:

exception select.error

OSError의 폐지된 별칭.

버전 3.3에서 변경: PEP 3151 [https://peps.python.org/pep-3151/]에 따라, 이 클래스는 OSError의 별칭이 되었습니다.

select.devpoll()

(Solaris와 파생 제품에서만 지원됩니다.) /dev/poll 폴링(polling) 객체를 반환합니다; devpoll 객체가 지원하는 메서드에 대해서는 아래의 /dev/poll 폴링 객체 섹션을 참조하십시오.

devpoll() objects are linked to the number of file descriptors allowed at the time of instantiation. If your program reduces this value, devpoll() will fail. If your program increases this value, devpoll() may return an incomplete list of active file descriptors.

새 파일 기술자는 상속 불가능합니다.

Added in version 3.3.

버전 3.4에서 변경: 새 파일 기술자는 이제 상속 불가능합니다.

select.epoll(sizehint=-1, flags=0)

(리눅스 2.5.44 이상에서만 지원됩니다.) I/O 이벤트를 위한 에지(Edge)나 레벨(Level) 트리거 되는 인터페이스로 사용할 수 있는 에지 폴링 객체를 반환합니다.

sizehint informs epoll about the expected number of events to be registered. It must be positive, or -1 to use the default. It is only used on older systems where epoll_create1() is not available; otherwise it has no effect (though its value is still checked).

flags는 폐지되었고 완전히 무시됩니다. 그러나, 제공되면, 값은 0이나 select.EPOLL_CLOEXEC여야 합니다. 그렇지 않으면 OSError가 발생합니다.

epolling 객체가 지원하는 메서드는 아래의 에지와 레벨 트리거 폴링 (epoll) 객체 섹션을 참조하십시오.

epoll 객체는 컨텍스트 관리자 프로토콜을 지원합니다: with 문에서 사용될 때, 새 파일 기술자는 블록 끝에서 자동으로 닫힙니다.

새 파일 기술자는 상속 불가능합니다.

버전 3.3에서 변경: flags 매개 변수를 추가했습니다.

버전 3.4에서 변경: with 문에 대한 지원이 추가되었습니다. 새로운 파일 기술자는 이제 상속 불가능합니다.

버전 3.4부터 폐지됨: flags 매개 변수. 이제 기본적으로 select.EPOLL_CLOEXEC가 사용됩니다. 파일 기술자를 상속 가능하게 하려면 os.set_inheritable()을 사용하십시오.

select.poll()

(모든 운영 체제에서 지원되는 것은 아닙니다.) 파일 기술자 등록과 등록 해지를 지원하고 그런 다음 I/O 이벤트에 대해 폴링하는 폴링 객체를 반환합니다; 폴링 객체가 지원하는 메서드에 대해서는 아래의 폴링 객체 섹션을 참조하십시오.

select.kqueue()

(BSD에서만 지원됩니다.) 커널 큐 객체를 반환합니다; kqueue 객체가 지원하는 메서드에 대해서는 아래의 Kqueue 객체 섹션을 참조하십시오.

새 파일 기술자는 상속 불가능합니다.

버전 3.4에서 변경: 새 파일 기술자는 이제 상속 불가능합니다.

select.kevent(ident, filter=KQ_FILTER_READ, flags=KQ_EV_ADD, fflags=0, data=0, udata=0)

(BSD에서만 지원됩니다.) 커널 이벤트 객체를 반환합니다. kevent 객체가 지원하는 메서드에 대해서는 아래의 Kevent 객체 섹션을 참조하십시오.

select.select(rlist, wlist, xlist[, timeout])

This is a straightforward interface to the Unix select() system call. The first three arguments are iterables of ‘waitable objects’: either integers representing file descriptors or objects with a parameterless method named fileno() returning such an integer:

rlist: 읽을 준비가 될 때까지 기다립니다

wlist: 쓰기 준비가 될 때까지 기다립니다

xlist: “예외 조건”을 기다립니다 (시스템에서 어떤 것들을 이러한 조건으로 간주하는지는 매뉴얼 페이지를 참조하십시오)

Empty iterables are allowed, but acceptance of three empty iterables is platform-dependent. (It is known to work on Unix but not on Windows.) The optional timeout argument specifies a time-out as a floating-point number in seconds. When the timeout argument is omitted the function blocks until at least one file descriptor is ready. A time-out value of zero specifies a poll and never blocks.

반환 값은 준비된 객체의 리스트 3개입니다: 처음 세 인자의 부분 집합입니다. 파일 기술자가 준비되지 않고 시간제한에 도달하면, 세 개의 빈 리스트가 반환됩니다.

이터러블에서 허용되는 객체 형에는 파이썬 파일 객체 (예를 들어 sys.stdin, 또는 open()이나 os.popen()에서 반환된 객체), socket.socket()에서 반환된 소켓 객체가 있습니다. 적절한 (단지 임의의 정수가 아니라 실제 파일 기술자를 반환하는) fileno() 메서드가 있는 한, 래퍼 (wrapper) 클래스를 직접 정의할 수도 있습니다.

참고

File objects on Windows are not acceptable, but sockets are. On Windows, the underlying select() function is provided by the WinSock library, and does not handle file descriptors that don’t originate from WinSock.

버전 3.5에서 변경: 시그널 처리기가 InterruptedError를 발생시키는 대신 예외를 발생시키는 경우(이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오)를 제외하고, 시그널에 의해 인터럽트 될 때 다시 계산된 시간제한으로 함수가 다시 시도됩니다.

select.PIPE_BUF

The minimum number of bytes which can be written without blocking to a pipe when the pipe has been reported as ready for writing by select(), poll() or another interface in this module. This doesn’t apply to other kind of file-like objects such as sockets.

이 값은 POSIX에서 512 이상이 되도록 보장합니다.

Availability: Unix

Added in version 3.2.

/dev/poll 폴링 객체

Solaris and derivatives have /dev/poll. While select() is O(highest file descriptor) and poll() is O(number of file descriptors), /dev/poll is O(active file descriptors).

/dev/poll behaviour is very close to the standard poll() object.

devpoll.close()

폴링 객체의 파일 기술자를 닫습니다.

Added in version 3.4.

devpoll.closed

폴링 객체가 닫혔으면 True.

Added in version 3.4.

devpoll.fileno()

폴링 객체의 파일 기술자 번호를 반환합니다.

Added in version 3.4.

devpoll.register(fd[, eventmask])

폴링 객체에 파일 기술자를 등록합니다. 이후 poll() 메서드에 대한 호출은 파일 기술자에 계류 중인 I/O 이벤트가 있는지 확인합니다. fd는 정수이거나, 정수를 반환하는 fileno() 메서드가 있는 객체일 수 있습니다. 파일 객체는 fileno()를 구현하므로, 인자로도 사용할 수 있습니다.

eventmask is an optional bitmask describing the type of events you want to check for. The constants are the same that with poll() object. The default value is a combination of the constants POLLIN, POLLPRI, and POLLOUT.

경고

Registering a file descriptor that’s already registered is not an error, but the result is undefined. The appropriate action is to unregister or modify it first. This is an important difference compared with poll().

devpoll.modify(fd[, eventmask])

이 메서드는 unregister() 다음에 register()를 수행합니다. 명시적으로 같은 작업을 수행하는 것보다 조금 더 효율적입니다.

devpoll.unregister(fd)

폴링 객체가 추적하는 파일 기술자를 제거합니다. register() 메서드와 마찬가지로, fd는 정수이거나 정수를 반환하는 fileno() 메서드가 있는 객체일 수 있습니다.

등록되지 않은 파일 기술자를 제거하려고 하면 안전하게 무시됩니다.

devpoll.poll([timeout])

Polls the set of registered file descriptors, and returns a possibly empty list containing (fd, event) 2-tuples for the descriptors that have events or errors to report. fd is the file descriptor, and event is a bitmask with bits set for the reported events for that descriptor — POLLIN for waiting input, POLLOUT to indicate that the descriptor can be written to, and so forth. An empty list indicates that the call timed out and no file descriptors had any events to report. If timeout is given, it specifies the length of time in milliseconds which the system will wait for events before returning. If timeout is omitted, -1, or None, the call will block until there is an event for this poll object.

버전 3.5에서 변경: 시그널 처리기가 InterruptedError를 발생시키는 대신 예외를 발생시키는 경우(이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오)를 제외하고, 시그널에 의해 인터럽트 될 때 다시 계산된 시간제한으로 함수가 다시 시도됩니다.

에지와 레벨 트리거 폴링 (epoll) 객체

https://linux.die.net/man/4/epoll

eventmask

상수

의미

EPOLLIN

읽기 가능

EPOLLOUT

쓰기 가능

EPOLLPRI

읽을 긴급 데이터

EPOLLERR

연관된 fd에서 에러 조건이 발생했습니다

EPOLLHUP

연관된 fd에서 끊어짐(hang up)이 발생했습니다

EPOLLET

에지 트리거 동작을 설정합니다, 기본값은 레벨 트리거 동작입니다

EPOLLONESHOT

원샷(one-shot) 동작을 설정합니다. 하나의 이벤트를 꺼낸 후에, fd는 내부적으로 비활성화됩니다.

EPOLLEXCLUSIVE

연관된 fd에 이벤트가 있을 때 하나의 epoll 객체만 깨웁니다. 기본값(이 플래그가 설정되지 않으면)은 fd를 폴링하는 모든 epoll 객체를 깨우는 것입니다.

EPOLLRDHUP

스트림 소켓 반대편이 연결을 닫았거나 연결의 쓰기 절반을 종료했습니다.

EPOLLRDNORM

EPOLLIN과 동등합니다

EPOLLRDBAND

우선순위가 높은 데이터 대역을 읽을 수 있습니다.

EPOLLWRNORM

EPOLLOUT과 동등합니다

EPOLLWRBAND

우선순위가 높은 데이터를 쓸 수 있습니다.

EPOLLMSG

무시됩니다.

Added in version 3.6: EPOLLEXCLUSIVE가 추가되었습니다. 리눅스 커널 4.5 이상에서만 지원됩니다.

epoll.close()

epoll 객체의 제어 파일 기술자를 닫습니다.

epoll.closed

epoll 객체가 닫혔으면 True.

epoll.fileno()

제어 fd의 파일 기술자 번호를 반환합니다.

epoll.fromfd(fd)

주어진 파일 기술자에서 epoll 객체를 만듭니다.

epoll.register(fd[, eventmask])

epoll 객체에 fd 기술자를 등록합니다.

epoll.modify(fd, eventmask)

등록된 파일 기술자를 수정합니다.

epoll.unregister(fd)

epoll 객체에서 등록된 파일 기술자를 제거합니다.

버전 3.9에서 변경: 이 메서드는 더는 EBADF 에러를 무시하지 않습니다.

epoll.poll(timeout=None, maxevents=-1)

이벤트를 기다립니다. 시간제한은 초 단위입니다 (float)

버전 3.5에서 변경: 시그널 처리기가 InterruptedError를 발생시키는 대신 예외를 발생시키는 경우(이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오)를 제외하고, 시그널에 의해 인터럽트 될 때 다시 계산된 시간제한으로 함수가 다시 시도됩니다.

폴링 객체

The poll() system call, supported on most Unix systems, provides better scalability for network servers that service many, many clients at the same time. poll() scales better because the system call only requires listing the file descriptors of interest, while select() builds a bitmap, turns on bits for the fds of interest, and then afterward the whole bitmap has to be linearly scanned again. select() is O(highest file descriptor), while poll() is O(number of file descriptors).

poll.register(fd[, eventmask])

폴링 객체에 파일 기술자를 등록합니다. 이후 poll() 메서드에 대한 호출은 파일 기술자에 계류 중인 I/O 이벤트가 있는지 확인합니다. fd는 정수이거나, 정수를 반환하는 fileno() 메서드가 있는 객체일 수 있습니다. 파일 객체는 fileno()를 구현하므로, 인자로도 사용할 수 있습니다.

eventmask는 확인할 이벤트 유형을 설명하는 선택적 비트 마스크이고, 아래 표에 설명된 상수 POLLIN, POLLPRI 및 POLLOUT의 조합일 수 있습니다. 지정하지 않으면, 사용되는 기본값은 3가지 유형의 이벤트를 모두 확인합니다.

상수

의미

POLLIN

읽을 데이터가 있습니다

POLLPRI

읽을 긴급한 데이터가 있습니다

POLLOUT

출력 준비: 쓰기가 블록 되지 않을 것입니다

POLLERR

어떤 종류의 에러 조건

POLLHUP

끊어졌습니다(Hung up)

POLLRDHUP

스트림 소켓 반대편이 연결을 닫았거나, 연결의 쓰기 절반을 종료했습니다

POLLNVAL

잘못된 요청: 기술자가 열리지 않았습니다

이미 등록된 파일 기술자를 등록하는 것은 에러가 아니며, 기술자를 정확히 한 번 등록하는 것과 같은 효과가 있습니다.

poll.modify(fd, eventmask)

이미 등록된 fd를 수정합니다. 이것은 register(fd, eventmask)와 같은 효과가 있습니다. 등록되지 않은 파일 기술자를 수정하려고 하면 errno ENOENT로 OSError 예외가 발생합니다.

poll.unregister(fd)

폴링 객체가 추적하는 파일 기술자를 제거합니다. register() 메서드와 마찬가지로, fd는 정수이거나 정수를 반환하는 fileno() 메서드가 있는 객체일 수 있습니다.

등록되지 않은 파일 기술자를 제거하려고 하면 KeyError 예외가 발생합니다.

poll.poll([timeout])

Polls the set of registered file descriptors, and returns a possibly empty list containing (fd, event) 2-tuples for the descriptors that have events or errors to report. fd is the file descriptor, and event is a bitmask with bits set for the reported events for that descriptor — POLLIN for waiting input, POLLOUT to indicate that the descriptor can be written to, and so forth. An empty list indicates that the call timed out and no file descriptors had any events to report. If timeout is given, it specifies the length of time in milliseconds which the system will wait for events before returning. If timeout is omitted, negative, or None, the call will block until there is an event for this poll object.

버전 3.5에서 변경: 시그널 처리기가 InterruptedError를 발생시키는 대신 예외를 발생시키는 경우(이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오)를 제외하고, 시그널에 의해 인터럽트 될 때 다시 계산된 시간제한으로 함수가 다시 시도됩니다.

Kqueue 객체

kqueue.close()

kqueue 객체의 제어 파일 기술자를 닫습니다.

kqueue.closed

kqueue 객체가 닫혔으면 True.

kqueue.fileno()

제어 fd의 파일 기술자 번호를 반환합니다.

kqueue.fromfd(fd)

주어진 파일 기술자에서 kqueue 객체를 만듭니다.

kqueue.control(changelist, max_events[, timeout]) → eventlist

kevent에 대한 저수준 인터페이스

changelist는 kevent 객체의 이터러블 이거나 None이어야 합니다

max_events는 0이거나 양의 정수여야 합니다.

timeout은 초 단위 (float 가능); 기본값은 None이고 무한히 대기합니다

버전 3.5에서 변경: 시그널 처리기가 InterruptedError를 발생시키는 대신 예외를 발생시키는 경우(이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오)를 제외하고, 시그널에 의해 인터럽트 될 때 다시 계산된 시간제한으로 함수가 다시 시도됩니다.

Kevent 객체

https://man.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2

kevent.ident

이벤트를 식별하는 데 사용되는 값. 해석은 필터에 따라 다르지만, 일반적으로 파일 기술자입니다. 생성자에서 ident 는 정수이거나 fileno() 메서드가 있는 객체일 수 있습니다. kevent는 내부적으로 정수를 저장합니다.

kevent.filter

커널 필터의 이름.

상수

의미

KQ_FILTER_READ

기술자를 취하고 읽을 수 있는 데이터가 있을 때마다 반환합니다

KQ_FILTER_WRITE

기술자를 취하고 쓸 수 있는 데이터가 있을 때마다 반환합니다

KQ_FILTER_AIO

AIO 요청

KQ_FILTER_VNODE

fflag에서 감시 중인 요청된 이벤트 중 하나 이상이 발생할 때 반환합니다

KQ_FILTER_PROC

프로세스 id에서 이벤트를 감시합니다

KQ_FILTER_NETDEV

Watch for events on a network device [not available on macOS]

KQ_FILTER_SIGNAL

감시하는 시그널이 프로세스에 전달될 때마다 반환합니다

KQ_FILTER_TIMER

임의의 타이머를 설정합니다

kevent.flags

필터 액션.

상수

의미

KQ_EV_ADD

이벤트를 추가하거나 수정합니다

KQ_EV_DELETE

큐에서 이벤트를 제거합니다

KQ_EV_ENABLE

이벤트를 반환하도록 Permitscontrol() 합니다

KQ_EV_DISABLE

이벤트 비활성화

KQ_EV_ONESHOT

처음 발생한 후 이벤트를 제거합니다

KQ_EV_CLEAR

이벤트를 꺼낸 후 상태를 재설정합니다

KQ_EV_SYSFLAGS

내부 이벤트

KQ_EV_FLAG1

내부 이벤트

KQ_EV_EOF

필터 특정 EOF 조건

KQ_EV_ERROR

반환 값을 봅니다

kevent.fflags

필터 특정 플래그.

KQ_FILTER_READ와 KQ_FILTER_WRITE 필터 플래그:

상수

의미

KQ_NOTE_LOWAT

소켓 버퍼의 낮은 수위(low water mark)

KQ_FILTER_VNODE 필터 플래그:

상수

의미

KQ_NOTE_DELETE

unlink()가 호출되었습니다

KQ_NOTE_WRITE

쓰기가 발생했습니다

KQ_NOTE_EXTEND

파일이 확장되었습니다

KQ_NOTE_ATTRIB

속성이 변경되었습니다

KQ_NOTE_LINK

링크 수가 변경되었습니다

KQ_NOTE_RENAME

파일 이름이 변경되었습니다

KQ_NOTE_REVOKE

파일에 대한 액세스가 취소되었습니다

KQ_FILTER_PROC 필터 플래그:

상수

의미

KQ_NOTE_EXIT

프로세스가 종료되었습니다

KQ_NOTE_FORK

프로세스가 fork()를 호출했습니다

KQ_NOTE_EXEC

프로세스가 새로운 프로세스를 실행했습니다

KQ_NOTE_PCTRLMASK

내부 필터 플래그

KQ_NOTE_PDATAMASK

내부 필터 플래그

KQ_NOTE_TRACK

fork()를 가로질러 프로세스를 추적합니다

KQ_NOTE_CHILD

NOTE_TRACK의 경우 자식 프로세스에서 반환됩니다

KQ_NOTE_TRACKERR

자식에게 연결할 수 없습니다

KQ_FILTER_NETDEV filter flags (not available on macOS):

상수

의미

KQ_NOTE_LINKUP

링크가 올라갔습니다

KQ_NOTE_LINKDOWN

링크가 내려갔습니다

KQ_NOTE_LINKINV

링크 상태가 유효하지 않습니다

kevent.data

필터 특정 데이터.

kevent.udata

사용자 정의 값.

selectors — High-level I/O multiplexing

Added in version 3.4.

소스 코드: Lib/selectors.py [https://github.com/python/cpython/tree/main/Lib/selectors.py]

소개

이 모듈은 select 모듈 프리미티브에 기반하여 고수준의 효율적인 I/O 다중화를 가능하게 합니다. 사용되는 OS 수준 프리미티브를 정확하게 제어하고 싶지 않으면, 사용자는 이 모듈을 대신 사용하는 것이 좋습니다.

It defines a BaseSelector abstract base class, along with several concrete implementations (KqueueSelector, EpollSelector…), that can be used to wait for I/O readiness notification on multiple file objects. In the following, “file object” refers to any object with a fileno() method, or a raw file descriptor. See file object.

DefaultSelector는 현재 플랫폼에서 사용할 수 있는 가장 효율적인 구현의 별칭입니다: 대부분 사용자는 기본적으로 이것을 선택해야 합니다.

참고

지원되는 파일 객체의 유형은 플랫폼에 따라 다릅니다: 윈도우에서는 소켓은 지원되지만, 파이프는 지원되지 않습니다. 반면에, 유닉스에서는 둘 다 지원됩니다 (fifo나 특수 파일 장치와 같은 다른 유형도 지원될 수 있습니다).

더 보기

select

저수준 I/O 다중화 모듈.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

클래스

클래스 계층 구조:

BaseSelector
+-- SelectSelector
+-- PollSelector
+-- EpollSelector
+-- DevpollSelector
+-- KqueueSelector

다음에서, events는 주어진 파일 객체에서 어떤 I/O 이벤트를 기다려야 하는지를 나타내는 비트 마스크입니다. 다음 모듈 상수의 조합일 수 있습니다:

상수

의미

selectors.EVENT_READ

읽기 가능

selectors.EVENT_WRITE

쓰기 가능

class selectors.SelectorKey

SelectorKey는 파일 객체에 그것의 하부 파일 기술자, 선택한 이벤트 마스크 및 첨부된 데이터를 연결하는 데 사용되는 namedtuple입니다. 여러 BaseSelector 메서드에 의해 반환됩니다.

fileobj

등록된 파일 객체.

fd

하부 파일 기술자.

events

이 파일 객체에서 기다려야 하는 이벤트.

data

이 파일 객체에 연결된 선택적인 불투명한 데이터: 예를 들어, 이것은 클라이언트별 세션 ID를 저장하는 데 사용될 수 있습니다.

class selectors.BaseSelector

BaseSelector는 여러 파일 객체에 대한 I/O 이벤트 준비를 기다리는 데 사용됩니다. 파일 스트림 등록, 등록 취소 및 선택적 제한 시간과 함께 해당 스트림에서 I/O 이벤트를 기다리는 메서드를 지원합니다. 추상 베이스 클래스이므로, 인스턴스를 만들 수 없습니다. DefaultSelector를 대신 사용하거나, 특정 구현을 사용하고 싶고, 플랫폼에서 지원한다면 SelectSelector, KqueueSelector 등을 사용하십시오. BaseSelector와 그것의 구상 구현은 컨텍스트 관리자 프로토콜을 지원합니다.

abstractmethod register(fileobj, events, data=None)

I/O 이벤트를 셀렉트하고 감시하기 위한 파일 객체를 등록합니다.

fileobj는 감시할 파일 객체입니다. 정수 파일 기술자이거나 fileno() 메서드를 가진 객체일 수 있습니다. events는 감시할 이벤트의 비트 마스크입니다. data는 불투명한 객체입니다.

새로운 SelectorKey 인스턴스를 반환하거나, 유효하지 않은 이벤트 마스크나 파일 기술자의 경우 ValueError를, 파일 객체가 이미 등록된 경우 KeyError를 발생시킵니다.

abstractmethod unregister(fileobj)

셀렉트로부터 파일 객체를 등록 해지하고, 감시에서 삭제합니다. 파일 객체는 닫히기 전에 등록 해지되어야 합니다.

fileobj는 이전에 등록된 파일 객체여야 합니다.

연결된 SelectorKey 인스턴스를 반환하거나, fileobj가 등록되어 있지 않으면 KeyError를 발생시킵니다. fileobj가 유효하지 않으면 (예를 들어, fileno() 메서드가 없거나 fileno() 메서드가 유효하지 않은 반환 값을 가지면) ValueError가 발생합니다.

modify(fileobj, events, data=None)

등록된 파일 객체의 감시되는 이벤트나 첨부된 데이터를 변경합니다.

This is equivalent to BaseSelector.unregister(fileobj) followed by BaseSelector.register(fileobj, events, data), except that it can be implemented more efficiently.

새로운 SelectorKey 인스턴스를 반환하거나, 유효하지 않은 이벤트 마스크나 파일 기술자의 경우 ValueError를, 파일 객체가 등록되지 않았으면 KeyError를 발생시킵니다.

abstractmethod select(timeout=None)

등록된 파일 객체의 일부가 준비될 때까지 기다리거나, 제한 시간이 만료됩니다.

timeout > 0 이면, 최대 대기 시간을 초로 지정합니다. timeout <= 0이면, 호출은 블록하지 않고, 현재 준비된 파일 객체를 보고합니다. timeout이 None이면, 감시되는 파일 객체가 준비될 때까지 호출이 블록 됩니다.

각 준비된 파일 객체마다 하나씩, (key, events) 튜플의 리스트를 반환합니다.

key는 준비된 파일 객체에 해당하는 SelectorKey 인스턴스입니다. events는 이 파일 객체에서 준비된 이벤트의 비트 마스크입니다.

참고

현재 프로세스가 시그널을 받으면, 이 메서드는 파일 객체가 준비되거나 제한 시간이 지나기 전에 반환할 수 있습니다: 이때는 빈 리스트가 반환됩니다.

버전 3.5에서 변경: 시그널에 의해 인터럽트 되었을 때, 셀렉터는 이제 시그널 처리기가 예외를 발생시키지 않으면, 제한 시간 이전에 빈 이벤트 리스트를 반환하는 대신, 재계산 된 제한 시간으로 재 시도됩니다 (근거는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하세요).

close()

셀렉터를 닫습니다.

모든 하부 자원을 해제하기 위해 이 메서드를 호출해야 합니다. 일단 닫은 후에는 셀렉터를 더는 사용하지 않아야 합니다.

get_key(fileobj)

등록된 파일 객체에 연결된 키를 반환합니다.

이 파일 객체에 연결된 SelectorKey 인스턴스를 반환하거나, 파일 객체가 등록되지 않았으면 KeyError를 발생시킵니다.

abstractmethod get_map()

파일 객체에서 셀렉터로의 매핑을 반환합니다.

등록된 파일 객체를 연결된 SelectorKey 인스턴스로 매핑하는 Mapping 인스턴스를 반환합니다.

class selectors.DefaultSelector

현재의 플랫폼에서 사용할 수 있는 가장 효율적인 구현을 사용하는 기본 셀렉터 클래스입니다. 대부분 사용자는 기본적으로 이것을 선택해야 합니다.

class selectors.SelectSelector

select.select() 기반 셀렉터.

class selectors.PollSelector

select.poll() 기반 셀렉터.

class selectors.EpollSelector

select.epoll() 기반 셀렉터.

fileno()

하부 select.epoll() 객체에서 사용하는 파일 기술자를 반환합니다.

class selectors.DevpollSelector

select.devpoll() 기반 셀렉터.

fileno()

하부 select.devpoll() 객체에서 사용하는 파일 기술자를 반환합니다.

Added in version 3.5.

class selectors.KqueueSelector

select.kqueue() 기반 셀렉터.

fileno()

하부 select.kqueue() 객체에서 사용하는 파일 기술자를 반환합니다.

예제

다음은 간단한 메아리 서버 구현입니다:

import selectors
import socket

sel = selectors.DefaultSelector()

def accept(sock, mask):
    conn, addr = sock.accept()  # Should be ready
    print('accepted', conn, 'from', addr)
    conn.setblocking(False)
    sel.register(conn, selectors.EVENT_READ, read)

def read(conn, mask):
    data = conn.recv(1000)  # Should be ready
    if data:
        print('echoing', repr(data), 'to', conn)
        conn.send(data)  # Hope it won't block
    else:
        print('closing', conn)
        sel.unregister(conn)
        conn.close()

sock = socket.socket()
sock.bind(('localhost', 1234))
sock.listen(100)
sock.setblocking(False)
sel.register(sock, selectors.EVENT_READ, accept)

while True:
    events = sel.select()
    for key, mask in events:
        callback = key.data
        callback(key.fileobj, mask)

signal — Set handlers for asynchronous events

Source code: Lib/signal.py [https://github.com/python/cpython/tree/main/Lib/signal.py]

이 모듈은 파이썬에서 시그널 처리기를 사용하는 메커니즘을 제공합니다.

일반 규칙

signal.signal() 함수는 시그널이 수신될 때 실행될 사용자 정의 처리기를 정의하도록 합니다. 소수의 기본 처리기가 설치됩니다: SIGPIPE는 무시되고 (그래서 파이프와 소켓에 대한 쓰기 에러는 일반 파이썬 예외로 보고될 수 있습니다) SIGINT는 부모 프로세스가 변경하지 않았다면 KeyboardInterrupt 예외로 번역됩니다.

일단 설정되면, 특정 시그널에 대한 처리기는 명시적으로 재설정 될 때까지 (파이썬은 하부 구현과 관계없이 BSD 스타일 인터페이스를 흉내 냅니다) 설치된 상태로 유지됩니다. SIGCHLD에 대한 처리기는 예외인데, 하부 구현을 따릅니다.

On WebAssembly platforms, signals are emulated and therefore behave differently. Several functions and signals are not available on these platforms.

파이썬 시그널 처리기의 실행

파이썬 시그널 처리기는 저수준 (C) 시그널 처리기 내에서 실행되지 않습니다. 대신, 저수준 시그널 처리기는 가상 기계에게 나중에 (예를 들어 다음 바이트 코드 명령에서) 해당 파이썬 시그널 처리기를 실행하도록 지시하는 플래그를 설정합니다. 결과는 다음과 같습니다:

C 코드에서의 유효하지 않은 연산으로 인해 발생하는 SIGFPE나 SIGSEGV와 같은 동기 에러를 잡는 것은 그리 의미가 없습니다. 파이썬은 시그널 처리기에서 C 코드로 돌아오는데, 같은 시그널을 다시 발생시켜서, 파이썬이 멈출 것입니다. 파이썬 3.3부터는, faulthandler 모듈을 사용하여 동기 에러를 보고할 수 있습니다.

C로만 구현된 오래 실행되는 계산(가령 커다란 텍스트 본문에 대한 정규식 일치)은 수신된 시그널에 상관없이 임의의 시간 동안 중단없이 실행될 수 있습니다. 계산이 끝나면 파이썬 시그널 처리기가 호출됩니다.

If the handler raises an exception, it will be raised “out of thin air” in the main thread. See the note below for a discussion.

시그널과 스레드

파이썬 시그널 처리기는 시그널이 다른 스레드에서 수신될 때도 항상 메인 인터프리터의 메인 파이썬 스레드에서 실행됩니다. 이는 시그널을 스레드 간 통신 수단으로 사용할 수 없음을 의미합니다. 대신 threading 모듈의 동기화 프리미티브를 사용할 수 있습니다.

게다가, 메인 인터프리터의 메인 스레드만 새로운 시그널 처리기를 설정할 수 있습니다.

모듈 내용

버전 3.5에서 변경: signal (SIG*), handler (SIG_DFL, SIG_IGN) and sigmask (SIG_BLOCK, SIG_UNBLOCK, SIG_SETMASK) related constants listed below were turned into enums (Signals, Handlers and Sigmasks respectively). getsignal(), pthread_sigmask(), sigpending() and sigwait() functions return human-readable enums as Signals objects.

The signal module defines three enums:

class signal.Signals

enum.IntEnum collection of SIG* constants and the CTRL_* constants.

Added in version 3.5.

class signal.Handlers

enum.IntEnum collection the constants SIG_DFL and SIG_IGN.

Added in version 3.5.

class signal.Sigmasks

enum.IntEnum collection the constants SIG_BLOCK, SIG_UNBLOCK and SIG_SETMASK.

Availability: Unix.

See the man page sigprocmask(2) [https://manpages.debian.org/sigprocmask(2)] and pthread_sigmask(3) [https://manpages.debian.org/pthread_sigmask(3)] for further information.

Added in version 3.5.

signal 모듈에 정의된 변수는 다음과 같습니다:

signal.SIG_DFL

이것은 두 가지 표준 시그널 처리 옵션 중 하나입니다; 단순히 시그널의 기본 기능을 수행합니다. 예를 들어, 대부분의 시스템에서 SIGQUIT의 기본 동작은 코어를 덤프하고 종료하는 것이지만, SIGCHLD의 기본 동작은 단순히 무시하는 것입니다.

signal.SIG_IGN

이것은 주어진 시그널을 무시하는 또 다른 표준 시그널 처리기입니다.

signal.SIGABRT

abort(3) [https://manpages.debian.org/abort(3)]로 부터의 중단 시그널.

signal.SIGALRM

alarm(2) [https://manpages.debian.org/alarm(2)]로 부터의 타이머 시그널.

Availability: Unix.

signal.SIGBREAK

키보드 인터럽트 (CTRL + BREAK).

Availability: Windows.

signal.SIGBUS

버스 에러 (메모리 액세스 불량).

Availability: Unix.

signal.SIGCHLD

자식 프로세스가 중지되었거나 종료되었습니다.

Availability: Unix.

signal.SIGCLD

SIGCHLD에 대한 별칭.

Availability: not macOS.

signal.SIGCONT

현재 중지되었으면 프로세스를 재개합니다.

Availability: Unix.

signal.SIGFPE

부동 소수점 예외. 예를 들어, 0으로 나누기.

더 보기

나누기나 모듈로 연산의 두 번째 인자가 0이면 ZeroDivisionError가 발생합니다.

signal.SIGHUP

제어 터미널이 끊어졌거나 제어 프로세스가 죽었습니다.

Availability: Unix.

signal.SIGILL

잘못된 명령어.

signal.SIGINT

키보드 인터럽트 (CTRL + C).

기본 액션은 KeyboardInterrupt를 발생시키는 것입니다.

signal.SIGKILL

킬 시그널.

잡거나, 차단하거나, 무시할 수 없습니다.

Availability: Unix.

signal.SIGPIPE

끊어진 파이프: 판독기가 없는 파이프에 쓰기.

기본 동작은 시그널을 무시하는 것입니다.

Availability: Unix.

signal.SIGSEGV

세그먼테이션 오류: 유효하지 않은 메모리 참조.

signal.SIGSTKFLT

Stack fault on coprocessor. The Linux kernel does not raise this signal: it can only be raised in user space.

Availability: Linux.

On architectures where the signal is available. See the man page signal(7) [https://manpages.debian.org/signal(7)] for further information.

Added in version 3.11.

signal.SIGTERM

종료 시그널.

signal.SIGUSR1

사용자 정의 시그널 1.

Availability: Unix.

signal.SIGUSR2

사용자 정의 시그널 2.

Availability: Unix.

signal.SIGWINCH

창 크기 조정 시그널.

Availability: Unix.

SIG*

모든 시그널 번호는 기호적으로 정의됩니다. 예를 들어, 행업(hangup) 시그널은 signal.SIGHUP으로 정의됩니다; 변수 이름은 <signal.h>에 있는 C 프로그램에서 사용되는 이름과 동일합니다. ‘signal()'에 대한 유닉스 매뉴얼 페이지는 존재하는 시그널을 나열합니다 (일부 시스템에서는 signal(2) [https://manpages.debian.org/signal(2)]이고, 다른 시스템에서는 signal(7) [https://manpages.debian.org/signal(7)]입니다). 모든 시스템이 같은 시그널 이름 집합을 정의하는 것은 아님에 유의하십시오; 시스템에서 정의한 이름만 이 모듈에서 정의합니다.

signal.CTRL_C_EVENT

Ctrl+C 키 입력 이벤트에 해당하는 시그널. 이 시그널은 os.kill()에서만 사용할 수 있습니다.

Availability: Windows.

Added in version 3.2.

signal.CTRL_BREAK_EVENT

Ctrl+Break 키 입력 이벤트에 해당하는 시그널. 이 시그널은 os.kill()에서만 사용할 수 있습니다.

Availability: Windows.

Added in version 3.2.

signal.NSIG

One more than the number of the highest signal number. Use valid_signals() to get valid signal numbers.

signal.ITIMER_REAL

간격 타이머(interval timer)를 실시간으로 감소시키고, 만료 시 SIGALRM을 전달합니다.

signal.ITIMER_VIRTUAL

프로세스가 실행 중일 때만 간격 타이머(interval timer)를 감소시키고, 만료 시 SIGVTALRM을 전달합니다.

signal.ITIMER_PROF

프로세스가 실행될 때와 시스템이 프로세스를 대신하여 실행될 때 간격 타이머(interval timer)를 감소시킵니다. ITIMER_VIRTUAL과 함께 사용되어, 이 타이머는 일반적으로 사용자와 커널 공간에서 응용 프로그램이 소비한 시간을 프로파일링하는 데 사용됩니다. 만료 시 SIGPROF를 전달합니다.

signal.SIG_BLOCK

pthread_sigmask()의 how 매개 변수에 가능한 값으로 시그널이 차단됨을 나타냅니다.

Added in version 3.3.

signal.SIG_UNBLOCK

pthread_sigmask()의 how 매개 변수에 가능한 값으로 시그널이 차단 해제됨을 나타냅니다.

Added in version 3.3.

signal.SIG_SETMASK

pthread_sigmask()의 how 매개 변수에 가능한 값으로 시그널 마스크가 교체됨을 나타냅니다.

Added in version 3.3.

signal 모듈은 하나의 예외를 정의합니다:

exception signal.ItimerError

하부 setitimer()나 getitimer() 구현으로부터의 에러를 알리기 위해 발생합니다. 유효하지 않은 간격 타이머나 음의 시간이 setitimer()에 전달되면 이 에러가 예상됩니다. 이 에러는 OSError의 서브 형입니다.

Added in version 3.3: 이 에러는 IOError의 서브 형이었습니다, 이제는 OSError의 별칭입니다.

signal 모듈은 다음 함수를 정의합니다:

signal.alarm(time)

time이 0이 아니면, 이 함수는 SIGALRM 시그널이 time 초 내에 프로세스로 전송되도록 요청합니다. 이전에 예약된 알람은 취소됩니다 (임의의 시간에 오직 하나의 알람만 예약될 수 있습니다). 반환된 값은 이전에 설정된 알람이 전달되기까지 남은 초(seconds)입니다. time이 0이면, 알람이 예약되지 않고, 예약된 알람이 취소됩니다. 반환 값이 0이면, 현재 예약된 알람이 없습니다.

Availability: Unix.

See the man page alarm(2) [https://manpages.debian.org/alarm(2)] for further information.

signal.getsignal(signalnum)

시그널 signalnum에 대한 현재 시그널 처리기를 반환합니다. 반환된 값은 콜러블 파이썬 객체이거나, 특수 값 signal.SIG_IGN, signal.SIG_DFL 중 하나이거나 None일 수 있습니다. 여기서 signal.SIG_IGN은 시그널이 이전에 무시되었음을 의미하고, signal.SIG_DFL은 시그널을 처리하는 기본 방법이 이전에 사용 중임을 의미하고, None은 이전 시그널 처리기가 파이썬에서 설치되지 않았음을 의미합니다.

signal.strsignal(signalnum)

Returns the description of signal signalnum, such as “Interrupt” for SIGINT. Returns None if signalnum has no description. Raises ValueError if signalnum is invalid.

Added in version 3.8.

signal.valid_signals()

이 플랫폼에서 유효한 시그널 번호 집합을 반환합니다. 일부 시그널이 시스템에서 내부 용으로 예약되었으면 range(1, NSIG)보다 작을 수 있습니다.

Added in version 3.8.

signal.pause()

시그널이 수신될 때까지 프로세스를 휴면 상태로 만듭니다; 그런 다음 적절한 처리기가 호출됩니다. 아무것도 반환하지 않습니다.

Availability: Unix.

See the man page signal(2) [https://manpages.debian.org/signal(2)] for further information.

sigwait(), sigwaitinfo(), sigtimedwait() 및 sigpending()도 참조하십시오.

signal.raise_signal(signum)

호출하는 프로세스에 시그널을 보냅니다. 아무것도 반환하지 않습니다.

Added in version 3.8.

signal.pidfd_send_signal(pidfd, sig, siginfo=None, flags=0)

파일 기술자 pidfd가 참조하는 프로세스로 시그널 sig를 보냅니다. 파이썬은 현재 siginfo 매개 변수를 지원하지 않습니다; None이어야 합니다. flags 인자는 향후 확장을 위해 제공됩니다; 현재는 플래그 값이 정의되어 있지 않습니다.

자세한 내용은 pidfd_send_signal(2) [https://manpages.debian.org/pidfd_send_signal(2)] 매뉴얼 페이지를 참조하십시오.

Availability: Linux >= 5.1, Android >= build-time API level 31

Added in version 3.9.

signal.pthread_kill(thread_id, signalnum)

시그널 signalnum을 호출자와 같은 프로세스의 다른 스레드인 스레드 thread_id로 보냅니다. 대상 스레드는 임의의 (파이썬이거나 아닌) 코드를 실행 중일 수 있습니다. 그러나, 대상 스레드가 파이썬 인터프리터를 실행 중이면, 파이썬 시그널 처리기는 메인 인터프리터의 메인 스레드에서 실행됩니다. 따라서, 특정 파이썬 스레드에 시그널을 보내는 것의 유일한 용도는 실행 중인 시스템 호출이 InterruptedError로 실패하도록 하는 것입니다.

Use threading.get_ident() or the ident attribute of threading.Thread objects to get a suitable value for thread_id.

signalnum이 0이면, 시그널이 전송되지 않지만, 여전히 에러 검사가 수행됩니다; 대상 스레드가 여전히 실행 중인지 확인하는 데 사용할 수 있습니다.

인자 thread_id, signalnum으로 감사 이벤트 signal.pthread_kill을 발생시킵니다.

Availability: Unix.

See the man page pthread_kill(3) [https://manpages.debian.org/pthread_kill(3)] for further information.

os.kill()도 참조하십시오.

Added in version 3.3.

signal.pthread_sigmask(how, mask)

호출하는 스레드의 시그널 마스크를 가져오거나 변경하거나 가져오면서 변경합니다. 시그널 마스크는 호출자에게 현재 배달이 차단된 시그널 집합입니다. 이전 시그널 마스크를 시그널 집합으로 반환합니다.

호출의 동작은 다음과 같이 how 값에 따라 다릅니다.

SIG_BLOCK: 차단된 시그널 집합은 현재 집합과 mask 인자의 합집합입니다.

SIG_UNBLOCK: mask에 있는 시그널이 차단된 시그널의 현재 집합에서 제거됩니다. 차단되지 않은 시그널을 차단 해제하려고 시도할 수 있습니다.

SIG_SETMASK: 차단된 시그널 집합이 mask 인자로 설정됩니다.

mask는 시그널 번호 집합입니다 (예를 들어 {signal.SIGINT, signal.SIGTERM}). 모든 시그널을 포함한 전체 마스크를 얻으려면 valid_signals()를 사용하십시오.

예를 들어, signal.pthread_sigmask(signal.SIG_BLOCK, [])은 호출하는 스레드의 시그널 마스크를 읽습니다.

SIGKILL과 SIGSTOP은 차단할 수 없습니다.

Availability: Unix.

See the man page sigprocmask(2) [https://manpages.debian.org/sigprocmask(2)] and pthread_sigmask(3) [https://manpages.debian.org/pthread_sigmask(3)] for further information.

pause(), sigpending() 및 sigwait()도 참조하십시오.

Added in version 3.3.

signal.setitimer(which, seconds, interval=0.0)

seconds(alarm()과 달리 float가 허용됩니다) 이후에 그리고 (interval이 0이 아니면) 그 후로 interval 초마다 발사(fire)하도록 which로 지정된 간격 타이머(signal.ITIMER_REAL, signal.ITIMER_VIRTUAL 또는 signal.ITIMER_PROF 중 하나)를 설정합니다. which로 지정된 간격 타이머는 seconds를 0으로 설정하여 지울 수 있습니다.

간격 타이머가 발사(fire)하면, 시그널이 프로세스로 전송됩니다. 전송된 시그널은 사용 중인 타이머에 따라 다릅니다; signal.ITIMER_REAL은 SIGALRM을, signal.ITIMER_VIRTUAL은 SIGVTALRM을, signal.ITIMER_PROF는 SIGPROF를 전달합니다.

이전 값은 튜플로 반환됩니다: (지연, 간격).

유효하지 않은 간격 타이머를 전달하려고 하면 ItimerError가 발생합니다.

Availability: Unix.

signal.getitimer(which)

which로 지정된 주어진 간격 타이머의 현재 값을 반환합니다.

Availability: Unix.

signal.set_wakeup_fd(fd, *, warn_on_full_buffer=True)

웨이크업 파일 기술자를 fd로 설정합니다. 시그널이 수신되면 시그널 번호는 단일 바이트로 fd에 기록됩니다. 라이브러리에서 poll이나 select 호출을 깨워서, 시그널을 완전히 처리하는 데 사용될 수 있습니다.

이전 웨이크업 fd가 반환됩니다 (또는 파일 기술자 웨이크업이 활성화되지 않았으면 -1). fd가 -1이면, 파일 기술자 웨이크업이 비활성화됩니다. -1이 아니면, fd는 비 블로킹이어야 합니다. poll이나 select를 다시 호출하기 전에 fd에서 바이트를 제거하는 것은 라이브러리의 책임입니다.

스레드가 활성화되었을 때, 이 함수는 메인 인터프리터의 메인 스레드에서만 호출할 수 있습니다; 다른 스레드에서 호출하려고 하면 ValueError 예외가 발생합니다.

이 함수를 사용하는 일반적인 두 가지 방법이 있습니다. 두 방법 모두, 시그널이 도착할 때 깨어나기 위해 fd를 사용하지만, 어떤 시그널이나 시그널들이 도착했는지 판단하는 방법이 다릅니다.

첫 번째 방법에서는, fd의 버퍼에서 데이터를 읽고, 바이트 값이 시그널 번호를 제공합니다. 이것은 간단합니다만, 드물게 문제가 될 수 있습니다: 일반적으로 fd에는 제한된 버퍼 공간이 있으며, 너무 많은 시그널이 너무 빨리 도착하면, 버퍼가 가득 차고, 일부 시그널이 손실될 수 있습니다. 이 방법을 사용하면, 시그널이 손실될 때 최소한 stderr에 경고가 인쇄되도록 warn_on_full_buffer=True를 설정해야 합니다.

두 번째 방법에서는, 오직 웨이크업만을 위해 웨이크업 fd를 사용하고, 실제 바이트 값은 무시합니다. 이 경우, 우리가 신경 쓰는 것은 fd의 버퍼가 비어 있는지 비어 있지 않은지 입니다; 가득 찬 버퍼는 전혀 문제를 가리키지 않습니다. 이 방법을 사용하면, 사용자가 가짜 경고 메시지로 혼동되지 않도록 warn_on_full_buffer=False를 설정해야 합니다.

버전 3.5에서 변경: 윈도우에서, 이 함수는 이제 소켓 핸들도 지원합니다.

버전 3.7에서 변경: warn_on_full_buffer 매개 변수를 추가했습니다.

signal.siginterrupt(signalnum, flag)

시스템 호출 재시작 동작을 변경합니다: flag가 False이면, 시그널 signalnum에 의해 인터럽트 될 때 시스템 호출이 다시 시작되고, 그렇지 않으면 시스템 호출이 중단됩니다. 아무것도 반환하지 않습니다.

Availability: Unix.

See the man page siginterrupt(3) [https://manpages.debian.org/siginterrupt(3)] for further information.

Note that installing a signal handler with signal() will reset the restart behaviour to interruptible by implicitly calling siginterrupt() with a true flag value for the given signal.

signal.signal(signalnum, handler)

시그널 signalnum의 처리기를 함수 handler로 설정합니다. handler는 두 개의 인자(아래를 참조하십시오)를 취하는 콜러블 파이썬 객체, 또는 특수 값 signal.SIG_IGN이나 signal.SIG_DFL 중 하나일 수 있습니다. 이전 시그널 처리기가 반환됩니다 (위의 getsignal() 설명을 참조하십시오). (자세한 내용은 유닉스 매뉴얼 페이지 signal(2) [https://manpages.debian.org/signal(2)]를 참조하십시오.)

스레드가 활성화되었을 때, 이 함수는 메인 인터프리터의 메인 스레드에서만 호출할 수 있습니다; 다른 스레드에서 호출하려고 하면 ValueError 예외가 발생합니다.

handler는 두 개의 인자로 호출됩니다: 시그널 번호와 현재 스택 프레임 (None이나 프레임 객체; 프레임 객체에 대한 설명은, 형 계층에 있는 설명을 참조하거나 inspect 모듈의 어트리뷰트 설명을 참조하십시오).

윈도우에서, signal()은 SIGABRT, SIGFPE, SIGILL, SIGINT, SIGSEGV, SIGTERM 또는 SIGBREAK로만 호출 할 수 있습니다. 다른 경우에는 ValueError가 발생합니다. 모든 시스템이 같은 시그널 이름 집합을 정의하는 것은 아님에 유의하십시오; 시그널 이름이 SIG* 모듈 수준 상수로 정의되지 않으면 AttributeError가 발생합니다.

signal.sigpending()

호출하는 스레드로 전달 계류 중인 시그널 집합을 검사합니다 (즉, 차단된 동안 발생한 시그널). 계류 중인 시그널 집합을 반환합니다.

Availability: Unix.

See the man page sigpending(2) [https://manpages.debian.org/sigpending(2)] for further information.

pause(), pthread_sigmask() 및 sigwait()도 참조하십시오.

Added in version 3.3.

signal.sigwait(sigset)

시그널 집합 sigset에 지정된 시그널 중 하나가 전달될 때까지 호출하는 스레드의 실행을 일시 중단합니다. 이 함수는 시그널을 받아들이고 (계류 중인 시그널 목록에서 제거합니다), 시그널 번호를 반환합니다.

Availability: Unix.

See the man page sigwait(3) [https://manpages.debian.org/sigwait(3)] for further information.

pause(), pthread_sigmask(), sigpending(), sigwaitinfo() 및 sigtimedwait()도 참조하십시오.

Added in version 3.3.

signal.sigwaitinfo(sigset)

시그널 집합 sigset에 지정된 시그널 중 하나가 전달될 때까지 호출하는 스레드의 실행을 일시 중단합니다. 이 함수는 시그널을 받아들이고 계류 중인 시그널 목록에서 제거합니다. sigset의 시그널 중 하나가 이미 호출하는 스레드에 대해 계류 중이면, 함수는 해당 시그널에 대한 정보와 함께 즉시 반환합니다. 전달된 시그널에 대해 시그널 처리기가 호출되지 않습니다. 이 함수는 sigset에 없는 시그널에 의해 중단되면 InterruptedError를 발생시킵니다.

반환 값은 siginfo_t 구조체에 포함된 데이터, 즉 si_signo, si_code, si_errno, si_pid, si_uid, si_status, si_band를 표현하는 객체입니다.

Availability: Unix.

See the man page sigwaitinfo(2) [https://manpages.debian.org/sigwaitinfo(2)] for further information.

pause(), sigwait() 및 sigtimedwait()도 참조하십시오.

Added in version 3.3.

버전 3.5에서 변경: 이 함수는 이제 sigset에 없는 시그널에 의해 중단되고 시그널 처리기가 예외를 발생시키지 않으면 재시도됩니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

signal.sigtimedwait(sigset, timeout)

Like sigwaitinfo(), but takes an additional timeout argument specifying a timeout. If timeout is specified as 0, a poll is performed. Returns None if a timeout occurs.

Availability: Unix.

See the man page sigtimedwait(2) [https://manpages.debian.org/sigtimedwait(2)] for further information.

pause(), sigwait() 및 sigwaitinfo()도 참조하십시오.

Added in version 3.3.

버전 3.5에서 변경: 이 함수는 이제 sigset에 없는 시그널에 의해 중단되고 시그널 처리기가 예외를 발생시키지 않으면 다시 계산된 timeout으로 재시도됩니다 (이유는 PEP 475 [https://peps.python.org/pep-0475/]를 참조하십시오).

Examples

다음은 최소한의 예제 프로그램입니다. alarm() 함수를 사용하여 파일을 여는 데 대기하는 시간을 제한합니다; 이것은 파일이 켜져 있지 않을 수 있는 직렬 장치를 위한 파일일 때 유용하며, 일반적으로 os.open()이 무기한 정지됩니다. 해결책은 파일을 열기 전에 5초 알람을 설정하는 것입니다; 작업이 너무 오래 걸리면, 알람 시그널이 전송되고, 처리기가 예외를 발생시킵니다.

import signal, os

def handler(signum, frame):
    signame = signal.Signals(signum).name
    print(f'Signal handler called with signal {signame} ({signum})')
    raise OSError("Couldn't open device!")

# Set the signal handler and a 5-second alarm
signal.signal(signal.SIGALRM, handler)
signal.alarm(5)

# This open() may hang indefinitely
fd = os.open('/dev/ttyS0', os.O_RDWR)

signal.alarm(0)          # Disable the alarm

SIGPIPE에 대한 참고 사항

프로그램의 출력을 head(1) [https://manpages.debian.org/head(1)]와 같은 도구로 파이핑 하면 표준 출력의 수신기가 일찍 닫힐 때 여러분의 프로세스로 SIGPIPE 시그널이 전송됩니다. 이것은 BrokenPipeError: [Errno 32] Broken pipe와 같은 예외를 일으킵니다. 이 경우를 처리하려면, 다음과 같이 이 예외를 포착하도록 진입점을 감싸십시오:

import os
import sys

def main():
    try:
        # simulate large output (your code replaces this loop)
        for x in range(10000):
            print("y")
        # flush output here to force SIGPIPE to be triggered
        # while inside this try block.
        sys.stdout.flush()
    except BrokenPipeError:
        # Python flushes standard streams on exit; redirect remaining output
        # to devnull to avoid another BrokenPipeError at shutdown
        devnull = os.open(os.devnull, os.O_WRONLY)
        os.dup2(devnull, sys.stdout.fileno())
        sys.exit(1)  # Python exits with error code 1 on EPIPE

if __name__ == '__main__':
    main()

Do not set SIGPIPE’s disposition to SIG_DFL in order to avoid BrokenPipeError. Doing that would cause your program to exit unexpectedly whenever any socket connection is interrupted while your program is still writing to it.

Note on Signal Handlers and Exceptions

If a signal handler raises an exception, the exception will be propagated to the main thread and may be raised after any bytecode instruction. Most notably, a KeyboardInterrupt may appear at any point during execution. Most Python code, including the standard library, cannot be made robust against this, and so a KeyboardInterrupt (or any other exception resulting from a signal handler) may on rare occasions put the program in an unexpected state.

To illustrate this issue, consider the following code:

class SpamContext:
    def __init__(self):
        self.lock = threading.Lock()

    def __enter__(self):
        # If KeyboardInterrupt occurs here, everything is fine
        self.lock.acquire()
        # If KeyboardInterrupt occurs here, __exit__ will not be called
        ...
        # KeyboardInterrupt could occur just before the function returns

    def __exit__(self, exc_type, exc_val, exc_tb):
        ...
        self.lock.release()

For many programs, especially those that merely want to exit on KeyboardInterrupt, this is not a problem, but applications that are complex or require high reliability should avoid raising exceptions from signal handlers. They should also avoid catching KeyboardInterrupt as a means of gracefully shutting down. Instead, they should install their own SIGINT handler. Below is an example of an HTTP server that avoids KeyboardInterrupt:

import signal
import socket
from selectors import DefaultSelector, EVENT_READ
from http.server import HTTPServer, SimpleHTTPRequestHandler

interrupt_read, interrupt_write = socket.socketpair()

def handler(signum, frame):
    print('Signal handler called with signal', signum)
    interrupt_write.send(b'\0')
signal.signal(signal.SIGINT, handler)

def serve_forever(httpd):
    sel = DefaultSelector()
    sel.register(interrupt_read, EVENT_READ)
    sel.register(httpd, EVENT_READ)

    while True:
        for key, _ in sel.select():
            if key.fileobj == interrupt_read:
                interrupt_read.recv(1)
                return
            if key.fileobj == httpd:
                httpd.handle_request()

print("Serving on port 8000")
httpd = HTTPServer(('', 8000), SimpleHTTPRequestHandler)
serve_forever(httpd)
print("Shutdown...")

mmap — Memory-mapped file support

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

메모리 맵 파일 객체는 동시에 bytearray 와 파일 객체처럼 작동합니다. bytearray를 기대하는 대부분 장소에서 mmap 객체를 사용할 수 있습니다. 예를 들어, re 모듈을 사용하여 메모리 맵 파일을 검색할 수 있습니다. obj[index] = 97를 사용해서 한 바이트를 변경하거나, 슬라이스에 대입하여 서브 시퀀스를 변경할 수도 있습니다: obj[i1:i2] = b'...'. 또한 현재 파일 위치에서 시작하여 데이터를 읽고 쓸 수 있고, 다른 위치로 파일을 seek() 할 수 있습니다.

A memory-mapped file is created by the mmap constructor, which is different on Unix and on Windows. In either case you must provide a file descriptor for a file opened for update. If you wish to map an existing Python file object, use its fileno() method to obtain the correct value for the fileno parameter. Otherwise, you can open the file using the os.open() function, which returns a file descriptor directly (the file still needs to be closed when done).

참고

쓰기 가능하고 버퍼링 되는 파일에 대한 메모리 맵을 만들려면, 먼저 파일을 flush()해야 합니다. 버퍼에 대한 지역 변경 사항이 실제로 매핑에 반영되게 하는 데 필요합니다.

유닉스와 윈도우 버전의 생성자 모두에서, access는 선택적 키워드 매개 변수로 지정될 수 있습니다. access는 ACCESS_READ, ACCESS_WRITE 또는 ACCESS_COPY 중 하나의 값을 받아, 읽기 전용, 동시 기록(write-through) 또는 쓸 때 복사(copy-on-write) 메모리를 각각 지정하거나, ACCESS_DEFAULT를 사용하여 prot로 위임합니다. access는 유닉스와 윈도우에서 모두 사용할 수 있습니다. access를 지정하지 않으면, 윈도우 mmap은 동시 기록(write-through) 매핑을 반환합니다. 세 가지 액세스 유형 모두에서 초기 메모리값은 지정된 파일에서 가져옵니다. ACCESS_READ 메모리 맵에 대입하면 TypeError 예외가 발생합니다. ACCESS_WRITE 메모리 맵에 대입하면 메모리와 하부 파일에 모두 영향을 줍니다. ACCESS_COPY 메모리 맵에 대입하면 메모리에는 영향을 미치지만, 하부 파일은 변경되지 않습니다.

버전 3.7에서 변경: ACCESS_DEFAULT 상수가 추가되었습니다.

익명 메모리를 매핑하려면, length와 함께 -1을 fileno로 전달해야 합니다.

class mmap.mmap(fileno, length, tagname=None, access=ACCESS_DEFAULT, offset=0)

(윈도우 버전) 파일 핸들 fileno로 지정된 파일의 length 바이트를 매핑하고, mmap 객체를 만듭니다. length가 파일의 현재 크기보다 크면, 파일은 length 바이트를 포함하도록 확장됩니다. length가 0 이면, 맵의 최대 길이는 파일의 현재 길이입니다. 단, 파일이 비어 있으면 윈도우에서 예외가 발생합니다 (윈도우에는 빈 매핑을 만들 수 없습니다).

tagname, if specified and not None, is a string giving a tag name for the mapping. Windows allows you to have many different mappings against the same file. If you specify the name of an existing tag, that tag is opened, otherwise a new tag of this name is created. If this parameter is omitted or None, the mapping is created without a name. Avoiding the use of the tagname parameter will assist in keeping your code portable between Unix and Windows.

offset은 음이 아닌 정수 오프셋으로 지정할 수 있습니다. mmap 참조는 파일 시작 부분으로부터의 오프셋에 상대적입니다. offset의 기본값은 0입니다. offset은 ALLOCATIONGRANULARITY의 배수여야 합니다.

인자 fileno, length, access, offset로 감사 이벤트(auditing event) mmap.__new__를 발생시킵니다.

class mmap.mmap(fileno, length, flags=MAP_SHARED, prot=PROT_WRITE | PROT_READ, access=ACCESS_DEFAULT, offset=0, *, trackfd=True)

(유닉스 버전) 파일 기술자 fileno로 지정된 파일의 length 바이트를 매핑하고, mmap 객체를 반환합니다. length가 0 이면, 맵의 최대 길이는 mmap가 호출될 때 파일의 현재 길이입니다.

flags specifies the nature of the mapping. MAP_PRIVATE creates a private copy-on-write mapping, so changes to the contents of the mmap object will be private to this process, and MAP_SHARED creates a mapping that’s shared with all other processes mapping the same areas of the file. The default value is MAP_SHARED. Some systems have additional possible flags with the full list specified in MAP_* constants.

prot가 지정되면 원하는 메모리 보호를 제공합니다; 가장 유용한 두 값은 페이지를 읽거나 쓰도록 지정할 수 있는 PROT_READ와 PROT_WRITE입니다. prot의 기본값은 PROT_READ | PROT_WRITE입니다.

access는 선택적 키워드 매개 변수로 flags 와 prot 대신 지정 될 수 있습니다. flags, prot 와 access를 모두 지정하는 것은 에러입니다. 이 매개 변수를 사용하는 방법에 대한 정보는 위의 access 설명을 참조하십시오.

offset은 음이 아닌 정수 오프셋으로 지정할 수 있습니다. mmap 참조는 파일 시작 부분으로부터의 오프셋에 상대적입니다. offset의 기본값은 0입니다. offset은 유닉스 시스템에서 PAGESIZE와 같은 ALLOCATIONGRANULARITY의 배수여야 합니다.

If trackfd is False, the file descriptor specified by fileno will not be duplicated, and the resulting mmap object will not be associated with the map’s underlying file. This means that the size() and resize() methods will fail. This mode is useful to limit the number of open file descriptors.

To ensure validity of the created memory mapping the file specified by the descriptor fileno is internally automatically synchronized with the physical backing store on macOS.

버전 3.13에서 변경: The trackfd parameter was added.

이 예제는 mmap을 사용하는 간단한 방법을 보여줍니다:

import mmap

# write a simple example file
with open("hello.txt", "wb") as f:
    f.write(b"Hello Python!\n")

with open("hello.txt", "r+b") as f:
    # memory-map the file, size 0 means whole file
    mm = mmap.mmap(f.fileno(), 0)
    # read content via standard file methods
    print(mm.readline())  # prints b"Hello Python!\n"
    # read content via slice notation
    print(mm[:5])  # prints b"Hello"
    # update content using slice notation;
    # note that new content must have same size
    mm[6:] = b" world!\n"
    # ... and read again using standard file methods
    mm.seek(0)
    print(mm.readline())  # prints b"Hello  world!\n"
    # close the map
    mm.close()

mmap은 with 문에서 컨텍스트 관리자로 사용할 수도 있습니다:

import mmap

with mmap.mmap(-1, 13) as mm:
    mm.write(b"Hello world!")

Added in version 3.2: 컨텍스트 관리자 지원.

다음 예제는 익명 맵을 만들고 부모와 자식 프로세스 간에 데이터를 교환하는 방법을 보여줍니다:

import mmap
import os

mm = mmap.mmap(-1, 13)
mm.write(b"Hello world!")

pid = os.fork()

if pid == 0:  # In a child process
    mm.seek(0)
    print(mm.readline())

    mm.close()

인자 fileno, length, access, offset로 감사 이벤트(auditing event) mmap.__new__를 발생시킵니다.

메모리 맵 파일 객체는 다음 메서드를 지원합니다:

close()

mmap를 닫습니다. 이후에 객체의 다른 메서드를 호출하면 ValueError 예외가 발생합니다. 열려있는 파일을 닫지 않습니다.

closed

파일이 닫혔으면 True입니다.

Added in version 3.2.

find(sub[, start[, end]])

서브 시퀀스 sub가 발견되는 객체에서 가장 낮은 인덱스를 반환합니다. sub는 [start, end] 범위에 포함되어야 합니다. 선택적 인자 start 와 end는 슬라이스 표기법처럼 해석됩니다. 실패하면 -1를 반환합니다.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

flush([offset[, size]])

파일의 메모리 내 복사본에 대한 변경 사항을 디스크로 플러시 합니다. 이 호출을 사용하지 않으면, 객체가 파괴되기 전에 변경 내용이 기록된다고 보장할 수 없습니다. offset과 size가 지정되면, 지정된 바이트 범위의 변경 사항만 디스크로 플러시 됩니다; 그렇지 않으면, 매핑의 전체 범위가 플러시 됩니다. offset은 PAGESIZE 나 ALLOCATIONGRANULARITY의 배수여야 합니다.

성공을 나타내기 위해 None이 반환됩니다. 호출이 실패하면 예외가 발생합니다.

버전 3.8에서 변경: 이전에는, 성공 시 0이 아닌 값이 반환되었습니다; 윈도우에서 에러 시 0이 반환되었습니다. 성공 시 0 값이 반환되었습니다; 유닉스에서 에러 시 예외가 발생했습니다.

madvise(option[, start[, length]])

start에서 시작하고 length 바이트만큼 확장하는 메모리 영역에 대해 커널에 조언 option을 보냅니다. option은 시스템에서 사용할 수 있는 MADV_* 상수 중 하나여야 합니다. start와 length가 생략되면, 전체 매핑으로 확장됩니다. 일부 시스템(리눅스 포함)에서, start는 PAGESIZE의 배수여야 합니다.

가용성: madvise() 시스템 호출이 있는 시스템.

Added in version 3.8.

move(dest, src, count)

오프셋 src에서 시작하는 count 바이트를 대상 인덱스 dest로 복사합니다. mmap이 ACCESS_READ로 만들어졌으면, move를 호출하면 TypeError 예외가 발생합니다.

read([n])

현재의 파일 위치로부터 최대 n 바이트를 포함하는 bytes를 반환합니다. 인자가 생략되거나 None 이거나 음수면, 현재 파일 위치에서 매핑의 끝까지 모든 바이트를 반환합니다. 파일 위치는 반환된 바이트의 뒤를 가리키도록 갱신됩니다.

버전 3.3에서 변경: 인자는 생략되거나 None 일 수 있습니다.

read_byte()

현재 파일 위치의 한 바이트를 정수로 반환하고, 파일 위치를 1 증가시킵니다.

readline()

현재 파일 위치에서 시작하여 다음 줄 바꿈까지 한 줄을 반환합니다. 반환된 바이트 뒤를 가리키도록 파일 위치가 갱신됩니다.

resize(newsize)

Resizes the map and the underlying file, if any.

Resizing a map created with access of ACCESS_READ or ACCESS_COPY, will raise a TypeError exception. Resizing a map created with with trackfd set to False, will raise a ValueError exception.

On Windows: Resizing the map will raise an OSError if there are other maps against the same named file. Resizing an anonymous map (ie against the pagefile) will silently create a new map with the original data copied over up to the length of the new size.

버전 3.11에서 변경: Correctly fails if attempting to resize when another map is held Allows resize against an anonymous map on Windows

rfind(sub[, start[, end]])

서브 시퀀스 sub가 발견되는 객체에서 가장 높은 인덱스를 반환합니다. sub는 [start, end] 범위에 포함되어야 합니다. 선택적 인자 start 와 end는 슬라이스 표기법처럼 해석됩니다. 실패하면 -1를 반환합니다.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

seek(pos[, whence])

파일의 현재 위치를 설정합니다. whence 인자는 선택적이며 기본값은 os.SEEK_SET 또는 0 (절대 파일 위치)입니다; 다른 값은 os.SEEK_CUR 또는 1 (현재 위치를 기준으로 seek)과 os.SEEK_END 또는 2 (파일의 끝을 기준으로 seek)입니다.

버전 3.13에서 변경: Return the new absolute position instead of None.

seekable()

Return whether the file supports seeking, and the return value is always True.

Added in version 3.13.

size()

파일의 길이를 반환합니다. 메모리 매핑된 영역의 크기보다 클 수 있습니다.

tell()

파일 포인터의 현재 위치를 반환합니다.

write(bytes)

bytes의 바이트를 파일 포인터의 현재 위치에 있는 메모리에 기록하고 기록된 바이트 수를 반환합니다 (쓰기가 실패하면 ValueError가 발생하기 때문에 결코 len(bytes)보다 작지 않습니다). 파일 위치는 기록된 바이트 뒤를 가리 키도록 갱신됩니다. mmap이 ACCESS_READ로 만들어졌으면, 기록할 때 TypeError 예외가 발생합니다.

버전 3.5에서 변경: 이제 쓰기 가능한 바이트열류 객체를 받아들입니다.

버전 3.6에서 변경: 이제 기록한 바이트 수가 반환됩니다.

write_byte(byte)

정수 byte를 파일 포인터의 현재 위치에 있는 메모리에 기록합니다; 파일 위치가 1 증가합니다. mmap이 ACCESS_READ로 만들어졌으면, 기록할 때 TypeError 예외가 발생합니다.

MADV_* 상수

mmap.MADV_NORMAL

mmap.MADV_RANDOM

mmap.MADV_SEQUENTIAL

mmap.MADV_WILLNEED

mmap.MADV_DONTNEED

mmap.MADV_REMOVE

mmap.MADV_DONTFORK

mmap.MADV_DOFORK

mmap.MADV_HWPOISON

mmap.MADV_MERGEABLE

mmap.MADV_UNMERGEABLE

mmap.MADV_SOFT_OFFLINE

mmap.MADV_HUGEPAGE

mmap.MADV_NOHUGEPAGE

mmap.MADV_DONTDUMP

mmap.MADV_DODUMP

mmap.MADV_FREE

mmap.MADV_NOSYNC

mmap.MADV_AUTOSYNC

mmap.MADV_NOCORE

mmap.MADV_CORE

mmap.MADV_PROTECT

mmap.MADV_FREE_REUSABLE

mmap.MADV_FREE_REUSE

이 옵션은 mmap.madvise()로 전달될 수 있습니다. 모든 시스템에서 모든 옵션이 제공되는 것은 아닙니다.

가용성: madvise() 시스템 호출이 있는 시스템.

Added in version 3.8.

MAP_* Constants

mmap.MAP_SHARED

mmap.MAP_PRIVATE

mmap.MAP_32BIT

mmap.MAP_ALIGNED_SUPER

mmap.MAP_ANON

mmap.MAP_ANONYMOUS

mmap.MAP_CONCEAL

mmap.MAP_DENYWRITE

mmap.MAP_EXECUTABLE

mmap.MAP_HASSEMAPHORE

mmap.MAP_JIT

mmap.MAP_NOCACHE

mmap.MAP_NOEXTEND

mmap.MAP_NORESERVE

mmap.MAP_POPULATE

mmap.MAP_RESILIENT_CODESIGN

mmap.MAP_RESILIENT_MEDIA

mmap.MAP_STACK

mmap.MAP_TPRO

mmap.MAP_TRANSLATED_ALLOW_EXECUTE

mmap.MAP_UNIX03

These are the various flags that can be passed to mmap.mmap(). MAP_ALIGNED_SUPER is only available at FreeBSD and MAP_CONCEAL is only available at OpenBSD. Note that some options might not be present on some systems.

버전 3.10에서 변경: Added MAP_POPULATE constant.

Added in version 3.11: Added MAP_STACK constant.

Added in version 3.12: Added MAP_ALIGNED_SUPER and MAP_CONCEAL constants.

Added in version 3.13: Added MAP_32BIT, MAP_HASSEMAPHORE, MAP_JIT, MAP_NOCACHE, MAP_NOEXTEND, MAP_NORESERVE, MAP_RESILIENT_CODESIGN, MAP_RESILIENT_MEDIA, MAP_TPRO, MAP_TRANSLATED_ALLOW_EXECUTE, and MAP_UNIX03 constants.

인터넷 데이터 처리

This chapter describes modules which support handling data formats commonly used on the internet.

email — An email and MIME handling package

email.message: Representing an email message

EmailMessage

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

set_param()

del_param()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

is_attachment()

get_content_disposition()

walk()

get_body()

iter_attachments()

iter_parts()

get_content()

set_content()

make_related()

make_alternative()

make_mixed()

add_related()

add_alternative()

add_attachment()

clear()

clear_content()

preamble

epilogue

defects

MIMEPart

email.parser: Parsing email messages

FeedParser API

BytesFeedParser

feed()

close()

FeedParser

Parser API

BytesParser

parse()

parsebytes()

BytesHeaderParser

Parser

parse()

parsestr()

HeaderParser

message_from_bytes()

message_from_binary_file()

message_from_string()

message_from_file()

추가 사항

email.generator: Generating MIME documents

BytesGenerator

flatten()

clone()

write()

Generator

flatten()

clone()

write()

DecodedGenerator

email.policy: Policy Objects

Policy

max_line_length

linesep

cte_type

raise_on_defect

mangle_from_

message_factory

verify_generated_headers

clone()

handle_defect()

register_defect()

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

EmailPolicy

utf8

refold_source

header_factory

content_manager

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

default

SMTP

SMTPUTF8

HTTP

strict

Compat32

mangle_from_

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

compat32

email.errors: Exception and Defect classes

MessageError

MessageParseError

HeaderParseError

BoundaryError

MultipartConversionError

HeaderWriteError

MessageDefect

HeaderDefect

email.headerregistry: Custom Header Objects

BaseHeader

name

defects

max_count

fold()

UnstructuredHeader

DateHeader

datetime

AddressHeader

groups

addresses

SingleAddressHeader

address

MIMEVersionHeader

version

major

minor

ParameterizedMIMEHeader

params

ContentTypeHeader

content_type

maintype

subtype

ContentDispositionHeader

content_disposition

ContentTransferEncoding

cte

HeaderRegistry

map_to_type()

__getitem__()

__call__()

Address

display_name

username

domain

addr_spec

__str__()

Group

display_name

addresses

__str__()

email.contentmanager: Managing MIME Content

ContentManager

get_content()

set_content()

add_get_handler()

add_set_handler()

콘텐츠 관리자 인스턴스

raw_data_manager

get_content()

set_content()

email: 예제

email.message.Message: compat32 API를 사용하여 이메일 메시지 표현하기

Message

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

attach()

get_payload()

set_payload()

set_charset()

get_charset()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

get_params()

get_param()

set_param()

del_param()

set_type()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

get_content_disposition()

walk()

preamble

epilogue

defects

email.mime: Creating email and MIME objects from scratch

MIMEBase

MIMENonMultipart

MIMEMultipart

MIMEApplication

MIMEAudio

MIMEImage

MIMEMessage

MIMEText

email.header: Internationalized headers

Header

append()

encode()

__str__()

__eq__()

__ne__()

decode_header()

make_header()

email.charset: Representing character sets

Charset

input_charset

header_encoding

body_encoding

output_charset

input_codec

output_codec

get_body_encoding()

get_output_charset()

header_encode()

header_encode_lines()

body_encode()

__str__()

__eq__()

__ne__()

add_charset()

add_alias()

add_codec()

email.encoders: Encoders

encode_quopri()

encode_base64()

encode_7or8bit()

encode_noop()

email.utils: Miscellaneous utilities

localtime()

make_msgid()

quote()

unquote()

parseaddr()

formataddr()

getaddresses()

parsedate()

parsedate_tz()

parsedate_to_datetime()

mktime_tz()

formatdate()

format_datetime()

decode_rfc2231()

encode_rfc2231()

collapse_rfc2231_value()

decode_params()

email.iterators: Iterators

body_line_iterator()

typed_subpart_iterator()

_structure()

json — JSON encoder and decoder

기본 사용법

dump()

dumps()

load()

loads()

인코더와 디코더

JSONDecoder

decode()

raw_decode()

JSONEncoder

default()

encode()

iterencode()

예외

JSONDecodeError

msg

doc

pos

lineno

colno

표준 준수와 상호 운용성

문자 인코딩

무한대와 NaN 숫자 값

오브젝트 내에서 반복된 이름

오브젝트나 배열이 아닌 최상윗값

구현 제약 사항

Command-line interface

Command-line options

mailbox — Manipulate mailboxes in various formats

Mailbox objects

Mailbox

add()

remove()

__delitem__()

discard()

__setitem__()

iterkeys()

keys()

itervalues()

__iter__()

values()

iteritems()

items()

get()

__getitem__()

get_message()

get_bytes()

get_string()

get_file()

__contains__()

__len__()

clear()

pop()

popitem()

update()

flush()

lock()

unlock()

close()

Maildir objects

Maildir

colon

list_folders()

get_folder()

add_folder()

remove_folder()

clean()

get_flags()

set_flags()

add_flag()

remove_flag()

get_info()

set_info()

add()

__setitem__()

update()

flush()

lock()

unlock()

close()

get_file()

mbox objects

mbox

get_file()

lock()

unlock()

MH objects

MH

list_folders()

get_folder()

add_folder()

remove_folder()

get_sequences()

set_sequences()

pack()

remove()

__delitem__()

discard()

lock()

unlock()

get_file()

flush()

close()

Babyl objects

Babyl

get_labels()

get_file()

lock()

unlock()

MMDF objects

MMDF

get_file()

lock()

unlock()

Message objects

Message

MaildirMessage objects

MaildirMessage

get_subdir()

set_subdir()

get_flags()

set_flags()

add_flag()

remove_flag()

get_date()

set_date()

get_info()

set_info()

mboxMessage objects

mboxMessage

get_from()

set_from()

get_flags()

set_flags()

add_flag()

remove_flag()

MHMessage objects

MHMessage

get_sequences()

set_sequences()

add_sequence()

remove_sequence()

BabylMessage objects

BabylMessage

get_labels()

set_labels()

add_label()

remove_label()

get_visible()

set_visible()

update_visible()

MMDFMessage objects

MMDFMessage

get_from()

set_from()

get_flags()

set_flags()

add_flag()

remove_flag()

예외

Error

NoSuchMailboxError

NotEmptyError

ExternalClashError

FormatError

예

mimetypes — Map filenames to MIME types

guess_type()

guess_file_type()

guess_all_extensions()

guess_extension()

init()

read_mime_types()

add_type()

inited

knownfiles

suffix_map

encodings_map

types_map

common_types

MimeTypes 객체

MimeTypes

suffix_map

encodings_map

types_map

types_map_inv

guess_extension()

guess_type()

guess_file_type()

guess_all_extensions()

read()

readfp()

read_windows_registry()

add_type()

base64 — Base16, Base32, Base64, Base85 Data Encodings

b64encode()

b64decode()

standard_b64encode()

standard_b64decode()

urlsafe_b64encode()

urlsafe_b64decode()

b32encode()

b32decode()

b32hexencode()

b32hexdecode()

b16encode()

b16decode()

a85encode()

a85decode()

b85encode()

b85decode()

z85encode()

z85decode()

decode()

decodebytes()

encode()

encodebytes()

Security Considerations

binascii — Convert between binary and ASCII

a2b_uu()

b2a_uu()

a2b_base64()

b2a_base64()

a2b_qp()

b2a_qp()

crc_hqx()

crc32()

b2a_hex()

hexlify()

a2b_hex()

unhexlify()

Error

Incomplete

quopri — Encode and decode MIME quoted-printable data

decode()

encode()

decodestring()

encodestring()

email — An email and MIME handling package

소스 코드: Lib/email/__init__.py [https://github.com/python/cpython/tree/main/Lib/email/__init__.py]

The email package is a library for managing email messages. It is specifically not designed to do any sending of email messages to SMTP (RFC 2821 [https://datatracker.ietf.org/doc/html/rfc2821.html]), NNTP, or other servers; those are functions of modules such as smtplib. The email package attempts to be as RFC-compliant as possible, supporting RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] and RFC 6532 [https://datatracker.ietf.org/doc/html/rfc6532.html], as well as such MIME-related RFCs as RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html], RFC 2046 [https://datatracker.ietf.org/doc/html/rfc2046.html], RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html], RFC 2183 [https://datatracker.ietf.org/doc/html/rfc2183.html], and RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html].

email 패키지의 전체 구조는 세 가지 주요 구성 요소와 다른 구성 요소의 동작을 제어하는 네 번째 구성 요소로 나눌 수 있습니다.

패키지의 중심 구성 요소는 전자 메일 메시지를 나타내는 “객체 모델”입니다. 응용 프로그램은 주로 message 서브 모듈에 정의된 객체 모델 인터페이스를 통해 패키지와 상호 작용합니다. 응용 프로그램은 이 API를 사용하여 기존 전자 메일에 대해 질문을 하거나, 새 전자 메일을 작성하거나, 같은 객체 모델 인터페이스를 사용하는 전자 메일 하위 구성 요소를 추가하거나 제거할 수 있습니다. 즉, 전자 메일 메시지와 MIME 하위 구성 요소의 특성에 따라, 전자 메일 객체 모델은 모두 EmailMessage API를 제공하는 객체의 트리 구조입니다.

패키지의 다른 두 가지 주요 구성 요소는 parser와 generator입니다. 구문 분석기(parser)는 직렬화된 전자 메일 메시지(바이트 스트림)를 가져와 EmailMessage 객체의 트리로 변환합니다. 생성기(generator)는 EmailMessage를 받아서 직렬화된 바이트 스트림으로 다시 변환합니다. (구문 분석기와 생성기는 텍스트 문자의 스트림도 처리하지만, 이 사용법은 유효하지 않은 메시지로 끝나기 쉬우므로 사용하지 않는 것이 좋습니다.)

제어 구성 요소는 policy 모듈입니다. 모든 EmailMessage, 모든 generator 및 모든 parser에는 그것의 동작을 제어하는 연관된 policy 객체가 있습니다. 일반적으로 응용 프로그램은 EmailMessage가 만들어질 때 정책을 지정하기만 하면 되는데, EmailMessage를 직접 인스턴스로 만들어서 새 전자 메일을 만들거나, parser를 사용하여 입력 스트림을 구문 분석할 때입니다. 그러나 메시지가 generator를 사용하여 직렬화될 때 정책을 변경할 수 있습니다. 이것은, 예를 들어, 범용 전자 메일 메시지를 디스크에서 구분 분석하지만, 전자 메일 서버로 보낼 때 표준 SMTP 설정을 사용하여 직렬화할 수 있도록 합니다.

email 패키지는 응용 프로그램으로부터 각종 관리적인 RFC의 세부 사항을 숨기기 위해 최선을 다합니다. 개념적으로 응용 프로그램은 전자 메일 메시지를 유니코드 텍스트와 바이너리 첨부 파일의 구조화 된 트리로 처리할 수 있어야 하며, 직렬화될 때 이것들이 어떻게 표시되는지 걱정할 필요가 없어야 합니다. 하지만, 실제로는, MIME 메시지와 그 구조, 특히 MIME “콘텐츠 형식(content type)”의 이름과 특성, 그리고 다중 부분 문서를 식별하는 방법을 관리하는 규칙 중 적어도 일부를 신경 쓸 필요가 종종 있습니다. 대부분, 이 지식은 더욱 복잡한 응용 프로그램에만 필요하며, 그럴 때도 그 구조가 어떻게 표현되는지에 대한 세부 사항이 아닌, 문제가 되는 고수준 구조에 관한 것이어야 합니다. MIME 콘텐츠 유형은 최신 인터넷 소프트웨어(전자 메일뿐만 아니라)에서 널리 사용되므로, 많은 프로그래머에게 익숙한 개념입니다.

다음 절에서는 email 패키지의 기능에 관해 설명합니다. 응용 프로그램에서 사용할 기본 인터페이스인 message 객체 모델부터 시작하여, parser와 generator 구성 요소를 다룹니다. 그런 다음 policy 제어를 다뤄서, 라이브러리의 주요 구성 요소를 마무리합니다.

다음 세 절에서는 패키지에서 발생할 수 있는 예외와 parser가 감지할 수 있는 결함(RFC를 준수하지 않는)에 관해 설명합니다. 그런 다음 headerregistry와 contentmanager 하위 구성 요소를 다룹니다. 이것들은 각각 헤더와 페이로드를 보다 자세하게 조작할 수 있는 도구를 제공합니다. 이 두 구성 요소는 모두 단순하지 않은 메시지를 소비하고 생성하는 것과 관련된 기능을 포함하지만, 고급 응용 프로그램이 관심을 가질 확장 API를 설명하기도 합니다.

그다음은 이전 절에서 다룬 API의 기본 부분들을 사용하는 일련의 예제입니다.

앞의 내용은 email 패키지의 최신(유니코드 친화적인) API를 나타냅니다. Message 클래스로 시작하는 나머지 절에서는 전자 메일 메시지가 표현되는 방법에 대한 세부 사항을 훨씬 직접 다루는 레거시 compat32 API를 다룹니다. compat32 API는 응용 프로그램으로부터 RFC 세부 사항을 숨기지 않습니다만, 그 수준에서 작동해야 하는 응용 프로그램에는 유용한 도구가 될 수 있습니다. 이 설명서는 과거 호환성을 위해 여전히 compat32 API를 사용하는 응용 프로그램과도 관련이 있습니다.

버전 3.6에서 변경: 새로운 EmailMessage/EmailPolicy API를 홍보하기 위해 설명서가 재구성되고 다시 작성되었습니다.

email 패키지 설명서의 목차:

email.message: Representing an email message

EmailMessage

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

set_param()

del_param()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

is_attachment()

get_content_disposition()

walk()

get_body()

iter_attachments()

iter_parts()

get_content()

set_content()

make_related()

make_alternative()

make_mixed()

add_related()

add_alternative()

add_attachment()

clear()

clear_content()

preamble

epilogue

defects

MIMEPart

email.parser: Parsing email messages

FeedParser API

BytesFeedParser

feed()

close()

FeedParser

Parser API

BytesParser

parse()

parsebytes()

BytesHeaderParser

Parser

parse()

parsestr()

HeaderParser

message_from_bytes()

message_from_binary_file()

message_from_string()

message_from_file()

추가 사항

email.generator: Generating MIME documents

BytesGenerator

flatten()

clone()

write()

Generator

flatten()

clone()

write()

DecodedGenerator

email.policy: Policy Objects

Policy

max_line_length

linesep

cte_type

raise_on_defect

mangle_from_

message_factory

verify_generated_headers

clone()

handle_defect()

register_defect()

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

EmailPolicy

utf8

refold_source

header_factory

content_manager

header_max_count()

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

default

SMTP

SMTPUTF8

HTTP

strict

Compat32

mangle_from_

header_source_parse()

header_store_parse()

header_fetch_parse()

fold()

fold_binary()

compat32

email.errors: Exception and Defect classes

MessageError

MessageParseError

HeaderParseError

BoundaryError

MultipartConversionError

HeaderWriteError

MessageDefect

HeaderDefect

email.headerregistry: Custom Header Objects

BaseHeader

name

defects

max_count

fold()

UnstructuredHeader

DateHeader

datetime

AddressHeader

groups

addresses

SingleAddressHeader

address

MIMEVersionHeader

version

major

minor

ParameterizedMIMEHeader

params

ContentTypeHeader

content_type

maintype

subtype

ContentDispositionHeader

content_disposition

ContentTransferEncoding

cte

HeaderRegistry

map_to_type()

__getitem__()

__call__()

Address

display_name

username

domain

addr_spec

__str__()

Group

display_name

addresses

__str__()

email.contentmanager: Managing MIME Content

ContentManager

get_content()

set_content()

add_get_handler()

add_set_handler()

콘텐츠 관리자 인스턴스

raw_data_manager

get_content()

set_content()

email: 예제

레거시 API:

email.message.Message: compat32 API를 사용하여 이메일 메시지 표현하기

Message

as_string()

__str__()

as_bytes()

__bytes__()

is_multipart()

set_unixfrom()

get_unixfrom()

attach()

get_payload()

set_payload()

set_charset()

get_charset()

__len__()

__contains__()

__getitem__()

__setitem__()

__delitem__()

keys()

values()

items()

get()

get_all()

add_header()

replace_header()

get_content_type()

get_content_maintype()

get_content_subtype()

get_default_type()

set_default_type()

get_params()

get_param()

set_param()

del_param()

set_type()

get_filename()

get_boundary()

set_boundary()

get_content_charset()

get_charsets()

get_content_disposition()

walk()

preamble

epilogue

defects

email.mime: Creating email and MIME objects from scratch

MIMEBase

MIMENonMultipart

MIMEMultipart

MIMEApplication

MIMEAudio

MIMEImage

MIMEMessage

MIMEText

email.header: Internationalized headers

Header

append()

encode()

__str__()

__eq__()

__ne__()

decode_header()

make_header()

email.charset: Representing character sets

Charset

input_charset

header_encoding

body_encoding

output_charset

input_codec

output_codec

get_body_encoding()

get_output_charset()

header_encode()

header_encode_lines()

body_encode()

__str__()

__eq__()

__ne__()

add_charset()

add_alias()

add_codec()

email.encoders: Encoders

encode_quopri()

encode_base64()

encode_7or8bit()

encode_noop()

email.utils: Miscellaneous utilities

localtime()

make_msgid()

quote()

unquote()

parseaddr()

formataddr()

getaddresses()

parsedate()

parsedate_tz()

parsedate_to_datetime()

mktime_tz()

formatdate()

format_datetime()

decode_rfc2231()

encode_rfc2231()

collapse_rfc2231_value()

decode_params()

email.iterators: Iterators

body_line_iterator()

typed_subpart_iterator()

_structure()

더 보기

모듈 smtplib

SMTP (Simple Mail Transport Protocol) 클라이언트

모듈 poplib

POP (Post Office Protocol) 클라이언트

모듈 imaplib

IMAP (Internet Message Access Protocol) 클라이언트

모듈 mailbox

다양한 표준 형식을 사용하여 디스크에 메시지 모음을 만들고, 읽고, 관리하는 도구.

email.message: Representing an email message

소스 코드: Lib/email/message.py [https://github.com/python/cpython/tree/main/Lib/email/message.py]

Added in version 3.6: [1]

email 패키지의 중심 클래스는 email.message 모듈에서 임포트 되는 EmailMessage 클래스입니다. email 객체 모델의 베이스 클래스입니다. EmailMessage는 헤더 필드 설정과 조회, 메시지 본문 액세스 및 구조화된 메시지 작성이나 수정을 위한 핵심 기능을 제공합니다.

전자 메일 메시지는 헤더(headers)와 페이 로드(payload)(내용(content)이라고도 합니다)로 구성됩니다. 헤더는 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]나 RFC 6532 [https://datatracker.ietf.org/doc/html/rfc6532.html] 스타일 필드 이름과 값이며, 필드 이름과 값은 콜론으로 구분됩니다. 콜론은 필드 이름이나 필드 값의 일부가 아닙니다. 페이 로드는 간단한 텍스트 메시지, 바이너리 객체 또는 각각 자신만의 헤더 집합과 자신만의 페이 로드를 갖는 서브 메시지들의 구조화된 시퀀스일 수 있습니다. 마지막 유형의 페이 로드는 multipart/*나 message/rfc822와 같은 MIME 유형을 가진 메시지로 표시됩니다.

EmailMessage 객체가 제공하는 개념적 모델은 메시지의 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 본문을 나타내는 payload와 결합 된 헤더들의 순서 있는 딕셔너리이며, 본문은 서브-EmailMessage 객체의 리스트일 수 있습니다. 헤더 이름과 값에 액세스하기 위한 일반적인 딕셔너리 메서드 외에도, 헤더에서 특수 정보(예를 들어 MIME 콘텐츠 유형)에 액세스하고, 페이 로드를 다루고, 메시지의 직렬화된 버전을 생성하고, 객체 트리를 재귀적으로 탐색하는 메서드가 있습니다.

The EmailMessage dictionary-like interface is indexed by the header names, which must be ASCII values. The values of the dictionary are strings with some extra methods. Headers are stored and returned in case-preserving form, but field names are matched case-insensitively. The keys are ordered, but unlike a real dict, there can be duplicates. Additional methods are provided for working with headers that have duplicate keys.

페이 로드는 간단한 메시지 객체의 경우 문자열이나 바이트열 객체이고, multipart/*와 message/rfc822 메시지 객체와 같은 MIME 컨테이너 문서에서는 EmailMessage 객체의 리스트입니다.

class email.message.EmailMessage(policy=default)

policy가 지정되면, 그것이 지정하는 규칙을 사용하여 메시지 표현을 갱신하고 직렬화합니다. policy가 설정되지 않으면, 줄 종료를 제외하고는 전자 메일 RFC 규칙을 따르는 default 정책을 사용합니다 (RFC가 요구하는 \r\n 대신에, 파이썬 표준 \n 줄 종료를 사용합니다). 자세한 내용은 policy 설명서를 참조하십시오.

as_string(unixfrom=False, maxheaderlen=None, policy=None)

Return the entire message flattened as a string. When optional unixfrom is true, the envelope header is included in the returned string. unixfrom defaults to False. For backward compatibility with the base Message class maxheaderlen is accepted, but defaults to None, which means that by default the line length is controlled by the max_line_length of the policy. The policy argument may be used to override the default policy obtained from the message instance. This can be used to control some of the formatting produced by the method, since the specified policy will be passed to the Generator.

문자열로의 변환을 완료하기 위해 기본값을 채워야 하면 메시지를 평평하게 만들 때 EmailMessage에 대한 변경이 발생할 수 있습니다 (예를 들어, MIME 경계(boundaries)가 생성되거나 수정될 수 있습니다).

이 메서드는 편의상 제공되며, 응용 프로그램에서 메시지를 직렬화하는 가장 유용한 방법은 아닐 수 있습니다, 특히 여러 메시지를 다룬다면 그렇습니다. 메시지 직렬화를 위한 더 유연한 API는 email.generator.Generator를 참조하십시오. 또한 이 메서드는 utf8가 False(기본값)일 때 “7비트 클린”으로 직렬화된 메시지를 생성하는 것으로 제한됩니다.

버전 3.6에서 변경: maxheaderlen이 지정되지 않았을 때의 기본 동작은 기본값을 0으로 하는 것에서 정책(policy)의 max_line_length 값을 기본값으로 사용하는 것으로 변경되었습니다.

__str__()

as_string(policy=self.policy.clone(utf8=True))와 동등합니다. str(msg)가 직렬화된 메시지를 포함하는 문자열을 읽을 수 있는 형식으로 생성할 수 있도록 합니다.

버전 3.4에서 변경: 이 메서드는 utf8=True를 사용하도록 변경되어, as_string()의 직접적인 별칭인 대신, RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html]과 유사한 메시지 표현을 생성합니다.

as_bytes(unixfrom=False, policy=None)

전체 메시지를 평평하게 만든 바이트열 객체를 반환합니다. 선택적 unixfrom이 참이면, 봉투 헤더(envelope header)가 반환된 문자열에 포함됩니다. unixfrom의 기본값은 False입니다. policy 인자는 메시지 인스턴스에서 얻은 기본 정책을 대체하는 데 사용될 수 있습니다. 지정된 policy가 BytesGenerator로 전달되기 때문에, 메서드가 생성하는 포매팅의 일부를 제어하는 데 사용할 수 있습니다.

문자열로의 변환을 완료하기 위해 기본값을 채워야 하면 메시지를 평평하게 만들 때 EmailMessage에 대한 변경이 발생할 수 있습니다 (예를 들어, MIME 경계(boundaries)가 생성되거나 수정될 수 있습니다).

이 메서드는 편의상 제공되며, 응용 프로그램에서 메시지를 직렬화하는 가장 유용한 방법은 아닐 수 있습니다, 특히 여러 메시지를 다룬다면 그렇습니다. 메시지 직렬화를 위한 더 유연한 API는 email.generator.BytesGenerator를 참조하십시오.

__bytes__()

Equivalent to as_bytes(). Allows bytes(msg) to produce a bytes object containing the serialized message.

is_multipart()

메시지의 페이 로드가 서브-EmailMessage 객체의 리스트면 True를, 그렇지 않으면 False를 반환합니다. is_multipart()가 False를 반환할 때, 페이 로드는 문자열 객체(CTE 인코딩된 바이너리 페이 로드일 수 있습니다)여야 합니다. True를 반환하는 is_multipart()가 반드시 “msg.get_content_maintype() == ‘multipart‘“가 True를 반환한다는 것을 의미하지는 않습니다. 예를 들어, EmailMessage가 message/rfc822 유형일 때 is_multipart는 True를 반환합니다.

set_unixfrom(unixfrom)

메시지의 봉투 헤더(envelope header)를 문자열이어야 하는 unixfrom으로 설정합니다. (이 헤더에 대한 간단한 설명은 mboxMessage를 참조하십시오.)

get_unixfrom()

메시지의 봉투 헤더(envelope header)를 반환합니다. 봉투 헤더가 설정되지 않았으면 기본값은 None입니다.

다음 메서드는 메시지 헤더에 액세스하기 위한 매핑류 인터페이스를 구현합니다. 이 메서드들과 일반 매핑(즉, 딕셔너리) 인터페이스 사이에는 의미상 차이가 있습니다. 예를 들어, 딕셔너리에는 중복 키가 없지만, 여기서는 중복 메시지 헤더가 있을 수 있습니다. 또한 딕셔너리에서는 keys()가 반환한 키의 순서가 보장되지 않지만, EmailMessage 객체에서는 헤더가 항상 원래 메시지에 나타난 순서대로, 또는 나중에 메시지에 추가된 순서대로 반환됩니다. 삭제한 후 다시 추가된 헤더는 항상 헤더 리스트의 끝에 추가됩니다.

이러한 의미적 차이는 의도적이며 가장 흔한 사용 사례에서의 편의를 추구하는 쪽으로 기울어져 있습니다.

모든 경우에, 메시지에 존재하는 봉투 헤더는 매핑 인터페이스에 포함되지 않습니다.

__len__()

중복을 포함하여, 총 헤더 수를 반환합니다.

__contains__(name)

메시지 객체에 name이라는 필드가 있으면 True를 반환합니다. 대소 문자를 구분하지 않고 일치하며, name은 후행 콜론을 포함하지 않습니다. in 연산자에 사용됩니다. 예를 들면:

if 'message-id' in myMessage:
   print('Message-ID:', myMessage['message-id'])

__getitem__(name)

이름으로 지정된 헤더 필드의 값을 반환합니다. name은 콜론 필드 구분자를 포함하지 않습니다. 헤더가 없으면 None이 반환됩니다; KeyError가 발생하지 않습니다.

이름이 지정된 필드가 메시지 헤더에 두 번 이상 나타나면, 해당 필드 값 중 정확히 어떤 필드 값이 반환되는지 정의되지 않습니다. get_all() 메서드를 사용하여 name으로 이름이 지정된 모든 기존 헤더의 값을 가져오십시오.

표준 (compat32가 아닌) 정책을 사용하여, 반환된 값은 email.headerregistry.BaseHeader의 서브 클래스 인스턴스입니다.

__setitem__(name, val)

필드 이름이 name이고 값이 val인 헤더를 메시지에 추가합니다. 필드는 메시지의 기존 헤더들 끝에 추가됩니다.

같은 이름을 가진 기존 헤더를 덮어쓰거나 삭제하지 않습니다. 새 헤더가 메시지에서 필드 이름이 name인 유일한 것이 되도록 하려면, 먼저 필드를 삭제하십시오. 예를 들어:

del msg['subject']
msg['subject'] = 'Python roolz!'

If the policy defines certain headers to be unique (as the standard policies do), this method may raise a ValueError when an attempt is made to assign a value to such a header when one already exists. This behavior is intentional for consistency’s sake, but do not depend on it as we may choose to make such assignments do an automatic deletion of the existing header in the future.

__delitem__(name)

메시지 헤더에서 이름이 name인 모든 필드를 삭제합니다. 해당 이름의 필드가 헤더에 없어도 예외가 발생하지 않습니다.

keys()

메시지의 모든 헤더 필드 이름의 리스트를 반환합니다.

values()

메시지의 모든 필드 값의 리스트를 반환합니다.

items()

메시지의 모든 필드 헤더와 값을 담은 2-튜플의 리스트를 반환합니다.

get(name, failobj=None)

Return the value of the named header field. This is identical to __getitem__() except that optional failobj is returned if the named header is missing (failobj defaults to None).

추가적인 유용한 헤더 관련 메서드는 다음과 같습니다:

get_all(name, failobj=None)

name으로 명명된 필드의 모든 값의 리스트를 반환합니다. 메시지에 그런 이름의 헤더가 없으면 failobj가 반환됩니다 (기본값은 None).

add_header(_name, _value, **_params)

확장된 헤더 설정. 이 메서드는 추가 헤더 파라미터가 키워드 인자로 제공될 수 있다는 점을 제외하고는 __setitem__()과 유사합니다. _name은 추가할 헤더 필드이고 _value는 헤더의 기본(primary)값입니다.

키워드 인자 딕셔너리 _params의 각 항목에 대해, 키는 파라미터 이름으로 사용되며 밑줄은 대시로 변환됩니다 (대시는 파이썬 식별자에서 유효하지 않기 때문입니다). 일반적으로, 값이 None이 아니면 파라미터가 key="value"로 추가되며, None이면 키만 추가됩니다.

값에 ASCII가 아닌 문자가 포함되면, 값을 (CHARSET, LANGUAGE, VALUE) 형식의 3-튜플로 지정하여 문자 집합과 언어를 명시적으로 제어 할 수 있습니다. 여기서 CHARSET은 값을 인코딩하는 데 사용할 문자 집합의 이름을 지정하는 문자열이고, LANGUAGE는 보통 None이나 빈 문자열(다른 가능성은 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]을 참조하십시오)로 설정되고, VALUE는 비 ASCII 코드 포인트를 포함하는 문자열 값입니다. 3-튜플이 전달되지 않고 값에 ASCII가 아닌 문자가 포함되면, CHARSET으로 utf-8, LANGUAGE로 None을 사용하여 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html] 형식으로 자동 인코딩됩니다.

예를 들면 다음과 같습니다:

msg.add_header('Content-Disposition', 'attachment', filename='bud.gif')

이것은 다음과 같은 헤더를 추가합니다

Content-Disposition: attachment; filename="bud.gif"

비 ASCII 문자가 있는 확장 인터페이스의 예:

msg.add_header('Content-Disposition', 'attachment',
               filename=('iso-8859-1', '', 'Fußballer.ppt'))

replace_header(_name, _value)

헤더를 교체합니다. 메시지에서 발견된 _name과 일치하는 첫 번째 헤더를 교체하고, 원래 헤더의 헤더 순서와 필드 이름 케이스(case)를 유지합니다. 일치하는 헤더가 없으면 KeyError를 발생시킵니다.

get_content_type()

maintype/subtype 형식의 소문자로 강제 변환된 메시지의 콘텐츠 유형을 반환합니다. 메시지에 Content-Type 헤더가 없으면 get_default_type()이 반환하는 값을 반환합니다. Content-Type 헤더가 유효하지 않으면 text/plain을 반환합니다.

(RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]에 따라, 메시지는 항상 기본 유형을 가지며, get_content_type()은 항상 값을 반환합니다. RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]는 multipart/digest 컨테이너 내에 등장하면 기본 유형이 message/rfc822이고, 그렇지 않으면 기본 유형을 text/plain으로 정의합니다. Content-Type 헤더가 유효하지 않은 유형 지정이면, RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]는 기본 유형을 text/plain으로 강제합니다.)

get_content_maintype()

메시지의 메인 콘텐츠 유형을 반환합니다. 이것은 get_content_type()이 반환한 문자열의 maintype 부분입니다.

get_content_subtype()

메시지의 서브 콘텐츠 유형을 반환합니다. 이것은 get_content_type()이 반환한 문자열의 subtype 부분입니다.

get_default_type()

기본 콘텐츠 유형을 반환합니다. multipart/digest 컨테이너의 서브 파트인 메시지를 제외하고 대부분의 메시지는 기본 콘텐츠 유형이 text/plain입니다. 이러한 서브 파트는 기본 콘텐츠 유형이 message/rfc822입니다.

set_default_type(ctype)

기본 콘텐츠 유형을 설정합니다. ctype은 text/plain이나 message/rfc822여야 하지만, 이것을 강제하지는 않습니다. 기본 콘텐츠 유형은 Content-Type 헤더에 저장되지 않기 때문에, 메시지에 Content-Type 헤더가 없을 때 get_content_type 메서드의 반환 값에만 영향을 줍니다.

set_param(param, value, header='Content-Type', requote=True, charset=None, language='', replace=False)

Content-Type 헤더에 파라미터를 설정합니다. 파라미터가 이미 헤더에 존재하면, 해당 값을 value로 바꿉니다. header가 Content-Type(기본값)이고 헤더가 메시지에 아직 없으면, 헤더를 추가하고 값을 text/plain으로 설정한 다음 새 파라미터 값을 추가합니다. 선택적 header는 Content-Type의 대체 헤더를 지정합니다.

값에 ASCII가 아닌 문자가 포함되면, 선택적 charset과 language 매개 변수를 사용하여 문자 집합과 언어를 명시적으로 지정할 수 있습니다. 선택적 language는 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html] 언어를 지정하며, 기본값은 빈 문자열입니다. charset과 language는 모두 문자열이어야 합니다. 기본값은 utf8 charset과 None language를 사용하는 것입니다.

replace가 False(기본값)이면 헤더는 헤더 리스트의 끝으로 이동합니다. replace가 True이면, 헤더는 제자리에서 갱신됩니다.

EmailMessage 객체에 requote 매개 변수를 사용하는 것은 폐지되었습니다.

Note that existing parameter values of headers may be accessed through the params attribute of the header value (for example, msg['Content-Type'].params['charset']).

버전 3.4에서 변경: replace 키워드가 추가되었습니다.

del_param(param, header='content-type', requote=True)

Content-Type 헤더에서 지정된 파라미터를 완전히 제거합니다. 헤더는 해당 파라미터나 그 값 없이 제자리에서 다시 작성됩니다. 선택적 header는 Content-Type의 대체 헤더를 지정합니다.

EmailMessage 객체에 requote 매개 변수를 사용하는 것은 폐지되었습니다.

get_filename(failobj=None)

메시지의 Content-Disposition 헤더의 filename 파라미터값을 반환합니다. 헤더에 filename 파라미터가 없으면, 이 메서드는 Content-Type 헤더에서 name 파라미터를 찾는 것으로 폴백(fallback)합니다. 둘 다 없거나 헤더가 없으면, failobj가 반환됩니다. 반환된 문자열은 항상 email.utils.unquote()에 따라 unquote 됩니다.

get_boundary(failobj=None)

메시지의 Content-Type 헤더의 boundary 파라미터값, 또는 헤더가 없거나 boundary 파라미터가 없으면 failobj를 반환합니다. 반환된 문자열은 항상 email.utils.unquote()에 따라 unquote 됩니다.

set_boundary(boundary)

Content-Type 헤더의 boundary 파라미터를 boundary로 설정합니다. 필요하면 set_boundary()는 항상 boundary를 quote 합니다. 메시지 객체에 Content-Type 헤더가 없으면 HeaderParseError가 발생합니다.

set_boundary()가 헤더 리스트에서 Content-Type 헤더의 순서를 유지하기 때문에, 이 메서드를 사용하는 것은 이전 Content-Type 헤더를 삭제하고 add_header()를 통해 새 boundary로 새 헤더를 추가하는 것과는 미묘한 차이가 있음에 유의하십시오.

get_content_charset(failobj=None)

Content-Type 헤더의 charset 파라미터를 소문자로 강제 변환하여 반환합니다. Content-Type 헤더가 없거나 헤더에 charset 파라미터가 없으면 failobj가 반환됩니다.

get_charsets(failobj=None)

메시지 내의 문자 집합 이름들을 포함하는 리스트를 반환합니다. 메시지가 multipart이면, 리스트는 페이 로드의 각 서브 파트마다 하나의 요소를 포함하며, 그렇지 않으면 길이 1인 리스트가 됩니다.

리스트의 각 항목은 표현된 서브 파트에 대한 Content-Type 헤더의 charset 파라미터의 값인 문자열입니다. 서브 파트에 Content-Type 헤더가 없거나, charset 파라미터가 없거나, text 메인 MIME 유형이 아니면, 반환된 리스트의 해당 항목은 failobj입니다.

is_attachment()

Content-Disposition 헤더가 있고 (대소 문자를 구분하지 않는) 값이 attachment이면 True를, 그렇지 않으면 False를 반환합니다.

버전 3.4.2에서 변경: is_multipart()와 일관성을 유지하기 위해, is_attachment는 이제 프로퍼티 대신 메서드입니다.

get_content_disposition()

메시지의 Content-Disposition 헤더가 있으면 소문자로 변환된 (파라미터 없는) 값을, 그렇지 않으면 None을 반환합니다. 메시지가 RFC 2183 [https://datatracker.ietf.org/doc/html/rfc2183.html]을 따르면, 이 메서드의 가능한 값은 inline, attachment 또는 None입니다.

Added in version 3.5.

다음 메서드는 메시지의 내용(페이 로드)을 조사하고 조작하는 것과 관련이 있습니다.

walk()

walk() 메서드는 메시지 객체 트리의 모든 파트와 서브 파트를 깊이 우선 탐색 순서로 이터레이트 하는 데 사용할 수 있는 범용 제너레이터입니다. 일반적으로 walk()를 for 루프에서 이터레이터로 사용합니다; 각 이터레이션은 다음 서브 파트를 반환합니다.

다음은 멀티 파트 메시지 구조의 모든 파트의 MIME 유형을 인쇄하는 예입니다:

>>> for part in msg.walk():
...     print(part.get_content_type())
multipart/report
text/plain
message/delivery-status
text/plain
text/plain
message/rfc822
text/plain

msg.get_content_maintype() == 'multipart'가 False를 반환하더라도, walk는 is_multipart()가 True를 반환하는 모든 파트의 서브 파트를 이터레이트 합니다. _structure 디버그 도우미 함수를 사용하여 예제에서 이를 확인할 수 있습니다:

>>> from email.iterators import _structure
>>> for part in msg.walk():
...     print(part.get_content_maintype() == 'multipart',
...           part.is_multipart())
True True
False False
False True
False False
False False
False True
False False
>>> _structure(msg)
multipart/report
    text/plain
    message/delivery-status
        text/plain
        text/plain
    message/rfc822
        text/plain

여기서 message 파트는 multiparts는 아니지만, 서브 파트를 포함합니다. is_multipart()는 True를 반환하고 walk는 서브 파트로 내려갑니다.

get_body(preferencelist=('related', 'html', 'plain'))

메시지의 “본문”이 될 수 있는 가장 적합한 후보인 MIME 파트를 반환합니다.

preferencelist는 related, html 및 plain 집합의 문자열 시퀀스이어야 하며, 반환된 파트의 콘텐츠 유형에 대한 선호 순서를 나타냅니다.

get_body 메서드가 호출된 객체와 일치하는 후보를 찾기 시작합니다.

related가 preferencelist에 포함되지 않으면, (서브) 파트가 선호와 일치하면 후보로 만난 모든 관련(related)의 루트 파트(또는 루트 파트의 서브 파트)를 고려합니다.

multipart/related와 만날 때, start 파라미터를 확인하고 일치하는 Content-ID가 있는 파트를 발견하면, 일치하는 후보를 찾을 때만 고려합니다. 그렇지 않으면 multipart/related의 첫 번째 (기본 루트) 파트만 고려합니다.

파트에 Content-Disposition 헤더가 있으면, 헤더 값이 inline일 때만 해당 파트를 후보로 간주합니다.

preferencelist의 선호 어느 것과도 일치하는 후보가 없으면, None을 반환합니다.

참고: (1) 대부분의 응용 프로그램에서 실제로 의미가 있는 preferencelist 조합은 ('plain',), ('html', 'plain') 및 기본 ('related', 'html', 'plain')뿐입니다. (2) get_body가 호출되는 객체에서 일치가 시작되므로, preferencelist가 기본값이면 multipart/related에서 get_body를 호출하면 객체 자신을 반환합니다. (3) Content-Type을 지정하지 않거나 Content-Type 헤더가 유효하지 않은 메시지(또는 메시지 파트)는 마치 text/plain 유형인 것처럼 처리되어, 간혹 get_body가 예기치 않은 결과를 반환하도록 합니다.

iter_attachments()

“본문” 파트 후보가 아닌 메시지의 모든 직접적인 서브 파트에 대한 이터레이터를 반환합니다. 즉, text/plain, text/html, multipart/related 또는 multipart/alternative 각각의 첫 번째 등장을 건너뛰고 (Content-Disposition: attachment를 통해 첨부 파일로 명시적으로 표시되지 않은 한), 나머지 모든 파트를 반환합니다. multipart/related에 직접 적용될 때, 루트 파트(즉: start 파라미터가 가리키는 파트나 start 파라미터가 없거나 start 파라미터가 파트들의 Content-ID와 일치하지 않으면 첫 번째 파트)를 제외한 모든 관련 파트에 대한 이터레이터를 반환합니다. multipart/alternative 또는 비-multipart에 직접 적용되면 빈 이터레이터를 반환합니다.

iter_parts()

메시지의 모든 직계 서브 파트에 대한 이터레이터를 반환합니다. multipart가 아니면 비어있게 됩니다. (walk()도 참조하십시오.)

get_content(*args, content_manager=None, **kw)

content_manager의 get_content() 메서드를 호출합니다. 추가 인자로 제공되는 인자나 키워드와 함께 self를 메시지 객체로 전달합니다. content_manager가 지정되지 않으면, 현재 policy가 지정하는 content_manager를 사용합니다.

set_content(*args, content_manager=None, **kw)

content_manager의 set_content() 메서드를 호출합니다. 추가 인자로 제공되는 인자나 키워드와 함께 self를 메시지 객체로 전달합니다. content_manager가 지정되지 않으면, 현재 policy가 지정하는 content_manager를 사용합니다.

make_related(boundary=None)

비 multipart 메시지를 multipart/related 메시지로 변환합니다. 기존 Content- 헤더와 페이 로드를 multipart의 (새로운) 첫 파트로 옮깁니다. boundary가 지정되면, multipart에서 경계 문자열로 사용하고, 그렇지 않으면 필요할 때 (예를 들어, 메시지가 직렬화될 때) 경계가 자동으로 만들어지도록 둡니다.

make_alternative(boundary=None)

비 multipart나 multipart/related를 multipart/alternative로 변환합니다. 기존 Content- 헤더와 페이 로드를 multipart의 (새로운) 첫 파트로 옮깁니다. boundary가 지정되면, multipart에서 경계 문자열로 사용하고, 그렇지 않으면 필요할 때 (예를 들어, 메시지가 직렬화될 때) 경계가 자동으로 만들어지도록 둡니다.

make_mixed(boundary=None)

비 multipart, multipart/related 또는 multipart-alternative를 multipart/mixed로 변환합니다. 기존 Content- 헤더와 페이 로드를 multipart의 (새로운) 첫 파트로 옮깁니다. boundary가 지정되면, multipart에서 경계 문자열로 사용하고, 그렇지 않으면 필요할 때 (예를 들어, 메시지가 직렬화될 때) 경계가 자동으로 만들어지도록 둡니다.

add_related(*args, content_manager=None, **kw)

메시지가 multipart/related이면, 새 메시지 객체를 만들고, 모든 인자를 그것의 set_content() 메서드에 전달하고, 그것을 multipart에 attach()합니다. 메시지가 multipart가 아니면, make_related()를 호출한 다음 위에서처럼 진행합니다. 메시지가 다른 유형의 multipart이면, TypeError를 발생시킵니다. content_manager가 지정되지 않으면, 현재 policy가 지정하는 content_manager를 사용합니다. 추가된 파트에 Content-Disposition 헤더가 없으면, 값 inline으로 추가합니다.

add_alternative(*args, content_manager=None, **kw)

메시지가 multipart/alternative이면, 새 메시지 객체를 만들고, 모든 인자를 그것의 set_content() 메서드에 전달하고, 그것을 multipart에 attach()합니다. 메시지가 multipart가 아니거나 multipart/related이면, make_alternative()를 호출한 다음 위에서처럼 진행합니다. 메시지가 다른 유형의 multipart이면, TypeError를 발생시킵니다. content_manager가 지정되지 않으면, 현재 policy가 지정하는 content_manager를 사용합니다.

add_attachment(*args, content_manager=None, **kw)

메시지가 multipart/mixed이면, 새 메시지 객체를 만들고, 모든 인자를 그것의 set_content() 메서드에 전달하고, 그것을 multipart에 attach()합니다. 메시지가 multipart가 아니거나, multipart/related나 multipart/alternative이면, make_mixed()를 호출한 다음 위에서처럼 진행합니다. content_manager가 지정되지 않으면, 현재 policy가 지정하는 content_manager를 사용합니다. 추가된 파트에 Content-Disposition 헤더가 없으면, 값 attachment로 추가합니다. 이 메서드는 content_manager에 적절한 옵션을 전달하여 명시적 첨부(Content-Disposition: attachment)와 inline 첨부(Content-Disposition: inline)에 모두 사용할 수 있습니다.

clear()

페이 로드와 모든 헤더를 제거합니다.

clear_content()

Remove the payload and all of the !Content- headers, leaving all other headers intact and in their original order.

EmailMessage 객체에는 다음과 같은 인스턴스 어트리뷰트가 있습니다:

preamble

MIME 문서의 형식은 헤더 다음의 빈 줄과 첫 번째 멀티 파트 경계 문자열 사이에 어떤 텍스트를 허용합니다. 일반적으로 이 텍스트는 표준 MIME 방어구를 벗어나기 때문에 MIME을 인식하는 메일 리더에서 보이지 않습니다. 그러나, 메시지의 원시 텍스트를 보거나, MIME을 인식하지 않는 리더에서 메시지를 볼 때 이 텍스트가 나타날 수 있습니다.

preamble 어트리뷰트는 MIME 문서에 있는 이 선행 방어구 밖 텍스트를 포함합니다. Parser가 헤더 다음이지만 첫 번째 경계 문자열 이전에 있는 어떤 텍스트를 발견하면, 이 텍스트를 메시지의 preamble 어트리뷰트에 대입합니다. Generator가 MIME 메시지의 일반 텍스트(plain text) 표현을 기록할 때, 메시지가 preamble 어트리뷰트를 가진 것을 발견하면, 헤더와 첫 번째 경계 사이의 영역에 이 텍스트를 씁니다. 자세한 내용은 email.parser와 email.generator를 참조하십시오.

메시지 객체에 preamble이 없으면, preamble 어트리뷰트는 None입니다.

epilogue

epilogue 어트리뷰트는 메시지의 마지막 경계와 끝 사이에 나타나는 텍스트를 포함한다는 점을 제외하고 preamble 어트리뷰트와 같은 방식으로 작동합니다. preamble과 마찬가지로 epilog 텍스트가 없으면, 이 어트리뷰트는 None입니다.

defects

defects 어트리뷰트는 이 메시지를 구문 분석할 때 발견된 모든 문제점의 리스트를 포함합니다. 가능한 구문 분석 결함에 대한 자세한 설명은 email.errors를 참조하십시오.

class email.message.MIMEPart(policy=default)

이 클래스는 MIME 메시지의 서브 파트를 나타냅니다. 서브 파트에는 자체 MIME-Version 헤더가 필요하지 않아서, set_content()를 호출할 때 MIME-Version 헤더가 추가되지 않는다는 점을 제외하면 EmailMessage와 같습니다.

각주

[1]

원래 3.4에서 잠정 모듈로 추가되었습니다. 레거시 메시지 클래스를 위한 설명서는 email.message.Message: compat32 API를 사용하여 이메일 메시지 표현하기로 옮겼습니다.

email.parser: Parsing email messages

소스 코드: Lib/email/parser.py [https://github.com/python/cpython/tree/main/Lib/email/parser.py]

메시지 객체 구조는 두 가지 방법으로 만들 수 있습니다: EmailMessage 객체를 만들고, 딕셔너리 인터페이스를 사용하여 헤더를 추가하고, set_content()와 관련 메서드를 사용하여 페이 로드를 추가하여 아예 새로 만들 수 있습니다. 또는 전자 메일 메시지의 직렬화된 표현을 구문 분석해서 만들 수 있습니다.

email 패키지는 MIME 문서를 포함한 대부분의 전자 우편 문서 구조를 이해하는 표준 구문 분석기를 제공합니다. 구문 분석기에 바이트열, 문자열 또는 파일 객체를 전달하면 구문 분석기가 객체 구조의 루트 EmailMessage 인스턴스를 반환합니다. MIME이 아닌 간단한 메시지의 경우 이 루트 객체의 페이 로드는 메시지의 텍스트를 포함하는 문자열일 수 있습니다. MIME 메시지의 경우 루트 객체는 is_multipart() 메서드가 True를 반환하고, get_body(), iter_parts() 및 walk()와 같은 페이 로드 조작 메서드를 통해 서브 파트에 액세스 할 수 있습니다.

실제로 사용 가능한 두 가지 구문 분석기 인터페이스가 있습니다, Parser API와 증분 FeedParser API. Parser API는 메시지의 전체 텍스트가 메모리에 있거나 전체 메시지가 파일 시스템의 파일에 있을 때 가장 유용합니다. 더 많은 입력을 기다리기 위해 블록할 수 있는 스트림에서 메시지를 읽을 때는 FeedParser가 더 적합합니다 (가령 소켓에서 전자 메일 메시지를 읽을 때). FeedParser는 메시지를 증분 적으로 소비하고 구문 분석 할 수 있으며, 구문 분석기를 닫을 때만 루트 객체를 반환합니다.

Note that the parser can be extended in limited ways, and of course you can implement your own parser completely from scratch. All of the logic that connects the email package’s bundled parser and the EmailMessage class is embodied in the Policy class, so a custom parser can create message object trees any way it finds necessary by implementing custom versions of the appropriate Policy methods.

FeedParser API

email.feedparser 모듈에서 임포트 한 BytesFeedParser는 전자 메일 메시지의 증분 구문 분석에 도움이 되는 API를 제공합니다. 블록할 수 있는 소스(가령 소켓)에서 전자 메일 메시지의 텍스트를 읽을 때 필요합니다. 물론 BytesFeedParser는 바이트열류 객체, 문자열 또는 파일에 완전히 포함된 전자 메일 메시지를 구문 분석하는 데 사용될 수 있지만, BytesParser API가 이러한 사용 사례에서는 더 편리 할 수 있습니다. 두 구문 분석기 API의 의미와 결과는 같습니다.

BytesFeedParser의 API는 간단합니다; 인스턴스를 만들고, 더는 공급할 것이 없을 때까지 바이트열을 공급한 다음 구문 분석기를 닫아 루트 메시지 객체를 얻습니다. BytesFeedParser는 표준 호환 메시지를 구문 분석할 때 매우 정확하고, 미준수 메시지를 구문 분석하는 데 매우 효과적이며 메시지를 어떻게 손상되었다고 간주하는지에 대한 정보를 제공합니다. 메시지에서 발견된 문제점 리스트로 메시지 객체의 defects 어트리뷰트를 채웁니다. 찾을 수 있는 결함 목록은 email.errors 모듈을 참조하십시오.

BytesFeedParser API는 다음과 같습니다:

class email.parser.BytesFeedParser(_factory=None, *, policy=policy.compat32)

BytesFeedParser 인스턴스를 만듭니다. 선택적 _factory는 인자 없는 콜러블입니다; 지정되지 않으면 policy의 message_factory를 사용합니다. 새로운 메시지 객체가 필요할 때마다 _factory를 호출합니다.

policy가 지정되면, 그것이 지정하는 규칙을 사용하여 메시지 표시를 갱신합니다. policy가 설정되지 않으면, compat32 정책을 사용합니다. 이 정책은 파이썬 3.2 버전의 email 패키지와의 호환성을 유지하고 Message를 기본 팩토리로 제공합니다. 다른 모든 정책은 EmailMessage를 기본 _factory로 제공합니다. policy가 제어하는 다른 기능에 대한 자세한 내용은 policy 설명서를 참조하십시오.

참고: policy 키워드는 항상 지정해야 합니다; 이후 버전의 파이썬에서는 기본값이 email.policy.default로 변경됩니다.

Added in version 3.2.

버전 3.3에서 변경: policy 키워드를 추가했습니다.

버전 3.6에서 변경: _factory는 기본적으로 정책 message_factory입니다.

feed(data)

구문 분석기에 데이터를 더 공급합니다. data는 하나 이상의 줄을 포함하는 바이트열류 객체여야 합니다. 줄은 부분적일 수 있고 구문 분석기는 그러한 부분적인 줄을 올바르게 이어붙입니다. 줄은 세 가지 일반 줄 종료 중 어느 것이라도 될 수 있습니다: 캐리지 리턴(carriage return), 줄 바꿈(newline) 또는 캐리지 리턴과 줄 바꿈 (이것들을 혼합할 수도 있습니다).

close()

이전에 제공된 모든 데이터의 구문 분석을 완료하고 루트 메시지 객체를 반환합니다. 이 메서드가 호출된 후 feed()가 호출되면 어떻게 되는지는 정의되지 않습니다.

class email.parser.FeedParser(_factory=None, *, policy=policy.compat32)

feed() 메서드에 대한 입력이 문자열이어야 한다는 점을 제외하고는 BytesFeedParser와 같게 작동합니다. 이러한 메시지가 유효할 수 있는 유일한 방법은 ASCII 텍스트만 포함하거나 utf8가 True일 때 바이너리 첨부 파일을 포함하지 않는 것이라서, 이것의 용도는 제한적입니다.

버전 3.3에서 변경: policy 키워드를 추가했습니다.

Parser API

email.parser 모듈에서 임포트 한 BytesParser 클래스는 메시지의 전체 내용이 바이트열류 객체나 파일로 있을 때 메시지를 구문 분석하는 데 사용할 수 있는 API를 제공합니다. email.parser 모듈은 또한 문자열 구문 분석을 위한 Parser와 메시지 헤더에만 관심이 있을 때 사용할 수 있는 헤더 전용 구문 분석기인 BytesHeaderParser와 HeaderParser를 제공합니다. BytesHeaderParser와 HeaderParser는 메시지 본문을 구문 분석하지 않고 페이 로드를 원시 본문으로 설정하기 때문에 이러한 상황에서 훨씬 더 빠를 수 있습니다.

class email.parser.BytesParser(_class=None, *, policy=policy.compat32)

BytesParser 인스턴스를 만듭니다. _class와 policy 인자는 BytesFeedParser 의 _factory와 policy 인자와 같은 의미입니다.

참고: policy 키워드는 항상 지정해야 합니다; 이후 버전의 파이썬에서는 기본값이 email.policy.default로 변경됩니다.

버전 3.3에서 변경: 2.4에서 폐지된 strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

버전 3.6에서 변경: _class는 기본적으로 정책 message_factory입니다.

parse(fp, headersonly=False)

바이너리 파일류 객체 fp에서 모든 데이터를 읽고, 결과 바이트열을 구문 분석한 후, 메시지 객체를 반환합니다. fp는 readline()과 read() 메서드를 모두 지원해야 합니다.

fp에 포함된 바이트열은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html](또는 utf8가 True이면, RFC 6532 [https://datatracker.ietf.org/doc/html/rfc6532.html]) 블록 스타일 헤더와 헤더 연장 줄들로 포맷되어야 하며, 선택적으로 봉투 헤더가 앞에 올 수 있습니다. 헤더 블록은 데이터 끝이나 빈 줄로 종료됩니다. 헤더 블록 다음에는 메시지 본문이 있습니다 (Content-Transfer-Encoding이 8bit인 서브 파트를 포함하여 MIME 인코딩된 서브 파트를 포함할 수 있습니다).

선택적 headersonly는 헤더를 읽은 후에 구문 분석을 중지할지를 지정하는 플래그입니다. 기본값은 False이며 파일의 전체 내용을 구문 분석합니다.

parsebytes(bytes, headersonly=False)

파일류 객체 대신 바이트열류 객체를 취한다는 점을 제외하고는 parse() 메서드와 유사합니다. 바이트열류 객체로 이 메서드를 호출하는 것은 BytesIO 인스턴스로 bytes를 먼저 감싸고 parse()를 호출하는 것과 동등합니다.

선택적 headersonly는 parse() 메서드와 같습니다.

Added in version 3.2.

class email.parser.BytesHeaderParser(_class=None, *, policy=policy.compat32)

headersonly의 기본값이 True라는 점을 제외하고는 BytesParser와 정확히 같습니다.

Added in version 3.3.

class email.parser.Parser(_class=None, *, policy=policy.compat32)

이 클래스는 BytesParser와 유사하지만, 문자열 입력을 처리합니다.

버전 3.3에서 변경: strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

버전 3.6에서 변경: _class는 기본적으로 정책 message_factory입니다.

parse(fp, headersonly=False)

텍스트 모드 파일류 객체 fp에서 모든 데이터를 읽고, 결과 텍스트를 구문 분석한 후, 루트 메시지 객체를 반환합니다. fp는 파일류 객체의 readline()과 read() 메서드를 모두 지원해야 합니다.

텍스트 모드 요구 사항 외에, 이 메서드는 BytesParser.parse()처럼 작동합니다.

parsestr(text, headersonly=False)

파일류 객체 대신 문자열 객체를 취한다는 점을 제외하고는 parse() 메서드와 유사합니다. 문자열로 이 메서드를 호출하는 것은 StringIO 인스턴스로 text를 먼저 감싸고 parse()를 호출하는 것과 동등합니다.

선택적 headersonly는 parse() 메서드와 같습니다.

class email.parser.HeaderParser(_class=None, *, policy=policy.compat32)

headersonly의 기본값이 True라는 점을 제외하고는 Parser와 정확히 같습니다.

문자열이나 파일 객체로부터 메시지 객체 구조를 만드는 것이 일반적인 작업이기 때문에, 편의상 4가지 함수가 제공됩니다. 최상위 email 패키지 이름 공간에 있습니다.

email.message_from_bytes(s, _class=None, *, policy=policy.compat32)

바이트열류 객체로부터 메시지 객체 구조를 반환합니다. 이것은 BytesParser().parsebytes(s)와 동등합니다. 선택적 _class와 policy는 BytesParser 클래스 생성자에서처럼 해석됩니다.

Added in version 3.2.

버전 3.3에서 변경: strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

email.message_from_binary_file(fp, _class=None, *, policy=policy.compat32)

열린 바이너리 파일 객체로부터 메시지 객체 구조 트리를 반환합니다. 이것은 BytesParser().parse(fp)와 동등합니다. _class와 policy는 BytesParser 클래스 생성자에서처럼 해석됩니다.

Added in version 3.2.

버전 3.3에서 변경: strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

email.message_from_string(s, _class=None, *, policy=policy.compat32)

문자열로부터 메시지 객체 구조 트리를 반환합니다. 이것은 Parser().parsestr(s)와 동등합니다. _class와 policy는 Parser 클래스 생성자에서처럼 해석됩니다.

버전 3.3에서 변경: strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

email.message_from_file(fp, _class=None, *, policy=policy.compat32)

열린 파일 객체로부터 메시지 객체 구조 트리를 반환합니다. 이것은 Parser().parse(fp)와 동등합니다. _class와 policy는 Parser 클래스 생성자에서처럼 해석됩니다.

버전 3.3에서 변경: strict 인자를 제거했습니다. policy 키워드를 추가했습니다.

버전 3.6에서 변경: _class는 기본적으로 정책 message_factory입니다.

대화식 파이썬 프롬프트에서 message_from_bytes()를 사용하는 방법의 예는 다음과 같습니다:

>>> import email
>>> msg = email.message_from_bytes(myBytes)

추가 사항

구문 분석 의미에 대한 참고 사항은 다음과 같습니다:

대부분의 multipart가 아닌 유형의 메시지는 문자열 페이 로드가 있는 단일 메시지 객체로 구문 분석됩니다. 이 객체는 is_multipart()가 False를 반환하고 iter_parts()는 빈 목록을 산출합니다.

모든 multipart 유형 메시지는 서브 메시지 객체 리스트 페이 로드가 있는 컨테이너 메시지 객체로 구문 분석됩니다. 바깥 컨테이너 메시지는 is_multipart()가 True를 반환하고 iter_parts()는 서브 파트 목록을 산출합니다.

콘텐츠 유형이 message/*(가령 message/delivery-status와 message/rfc822)인 대부분의 메시지는 길이가 1인 리스트 페이 로드를 포함하는 컨테이너 객체로 구문 분석됩니다. is_multipart() 메서드는 True를 반환합니다. iter_parts()가 산출하는 단일 요소가 서브 메시지 객체입니다.

일부 표준을 준수하지 않는 메시지는 multipart 처리에 대해 내부적으로 일관성이 없을 수 있습니다. 이러한 메시지는 multipart 유형의 Content-Type 헤더를 가지면서도 is_multipart() 메서드가 False를 반환할 수 있습니다. 이러한 메시지가 FeedParser로 구문 분석되었다면, defects 어트리뷰트 리스트에 MultipartInvariantViolationDefect 클래스의 인스턴스가 있습니다. 자세한 내용은 email.errors를 참조하십시오.

email.generator: Generating MIME documents

소스 코드: Lib/email/generator.py [https://github.com/python/cpython/tree/main/Lib/email/generator.py]

One of the most common tasks is to generate the flat (serialized) version of the email message represented by a message object structure. You will need to do this if you want to send your message via smtplib.SMTP.sendmail(), or print the message on the console. Taking a message object structure and producing a serialized representation is the job of the generator classes.

email.parser 모듈과 마찬가지로 번들 제너레이터의 기능으로 제한되지 않습니다; 처음부터 직접 작성할 수 있습니다. 그러나 번들 제너레이터는 표준 호환 방식으로 대부분 전자 우편을 생성하는 방법을 알고 있고, MIME과 비 MIME 전자 우편 메시지를 잘 처리하며, 변환 없는 같은 policy가 사용된다고 가정할 때 바이트열 지향 구문 분석과 생성 연산이 역이 되도록 설계되었습니다. 즉, BytesParser 클래스로 직렬화된 바이트 스트림을 구문 분석한 다음, BytesGenerator를 사용하여 직렬화된 바이트 스트림을 재생성하면 입력과 동일한 출력이 생성됩니다 [1]. (반면에, 프로그램에서 구축한 EmailMessage에 제너레이터를 사용하면 기본값이 채워지기 때문에 EmailMessage 객체가 변경될 수 있습니다.)

Generator 클래스를 사용하면 메시지를 (바이너리가 아닌) 텍스트 직렬화 표현으로 펼칠 수 있지만, 유니코드는 바이너리 데이터를 직접 표현할 수 없기 때문에, “8비트 클린”하지 않은 채널을 통한 전송을 위한 전자 우편 메시지를 인코딩하기 위한 표준 전자 우편 RFC 콘텐츠 전송 인코딩(Content Transfer Encoding) 기술을 사용하여 메시지를 ASCII 문자만 포함된 것으로 변환해야 합니다.

SMIME 서명된 메시지의 재현성 있는 처리를 위해 Generator는 multipart/signed 유형의 메시지 파트와 모든 서브 부분에 대해 헤더 접기를 비활성화합니다.

class email.generator.BytesGenerator(outfp, mangle_from_=None, maxheaderlen=None, *, policy=None)

flatten() 메서드에 제공된 모든 메시지나 write() 메서드에 제공된 모든 서로게이트 이스케이프 인코딩된 텍스트를 파일류 객체 outfp에 쓰는 BytesGenerator 객체를 반환합니다. outfp는 바이너리 데이터를 받아들이는 write 메서드를 지원해야 합니다.

If optional mangle_from_ is True, put a > character in front of any line in the body that starts with the exact string "From ", that is From followed by a space at the beginning of a line. mangle_from_ defaults to the value of the mangle_from_ setting of the policy (which is True for the compat32 policy and False for all others). mangle_from_ is intended for use when messages are stored in Unix mbox format (see mailbox and WHY THE CONTENT-LENGTH FORMAT IS BAD [https://www.jwz.org/doc/content-length.html]).

maxheaderlen이 None이 아니면, maxheaderlen보다 긴 헤더 줄을 다시 접거나, 0이면 헤더를 다시 접지 않습니다. manheaderlen이 None(기본값)이면, policy 설정에 따라 헤더와 기타 메시지 줄을 줄 바꿈 합니다.

policy가 지정되면, 해당 정책을 사용하여 메시지 생성을 제어합니다. policy가 None(기본값)이면 flatten에 전달된 Message나 EmailMessage 객체와 연관된 정책을 사용하여 메시지 생성을 제어합니다. policy가 제어하는 것에 대한 자세한 내용은 email.policy를 참조하십시오.

Added in version 3.2.

버전 3.3에서 변경: policy 키워드를 추가했습니다.

버전 3.6에서 변경: mangle_from_과 maxheaderlen 매개 변수의 기본 동작은 정책을 따르는 것입니다.

flatten(msg, unixfrom=False, linesep=None)

msg를 루트로 하는 메시지 객체 구조의 텍스트 표현을 BytesGenerator 인스턴스가 만들어질 때 지정된 출력 파일에 인쇄합니다.

policy 옵션 cte_type이 8bit(기본값)이면, 하이 비트가 설정된 바이트들이 원본에서와같이 재생성되도록 출력이 수정되지 않은 원본 구문 분석된 메시지의 헤더를 복사하고, 비 ASCII Content-Transfer-Encoding을 이것을 갖는 모든 본문 파트에서 보존합니다. cte_type이 7bit이면, 하이 비트가 설정된 바이트들을 ASCII 호환 Content-Transfer-Encoding을 사용하여 필요에 따라 변환합니다. 즉, 비 ASCII Content-Transfer-Encoding(Content-Transfer-Encoding: 8bit)을 갖는 파트를 ASCII 호환 Content-Transfer-Encoding으로 변환하고, 헤더에 있는 RFC 유효하지 않은 비 ASCII 바이트를 MIME unknown-8bit 문자 집합을 사용하여 인코딩하여, RFC 호환되게 만듭니다.

unixfrom이 True이면, 루트 메시지 객체의 첫 번째 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 헤더 앞에 유닉스 mailbox 형식(mailbox를 참조하십시오)에서 사용되는 봉투 헤더 구분자를 인쇄합니다. 루트 객체에 봉투 헤더가 없으면, 표준 헤더를 만듭니다. 기본값은 False입니다. 서브 파트의 경우 봉투 헤더가 인쇄되지 않음에 유의하십시오.

linesep이 None이 아니면, 펼쳐진 메시지의 모든 줄 사이의 구분자 문자로 사용합니다. linesep이 None(기본값)이면, policy에 지정된 값을 사용합니다.

clone(fp)

정확히 같은 옵션 설정이고 fp를 새 outfp로 사용하는, 이 BytesGenerator 인스턴스의 독립 클론을 반환합니다.

write(s)

ASCII 코덱과 surrogateescape 에러 처리기를 사용하여 s를 인코딩하고, BytesGenerator의 생성자에 전달된 outfp의 write 메서드로 전달합니다.

편의상, EmailMessage는 as_bytes() 메서드와 bytes(aMessage)(일명 __bytes__())를 제공하여 메시지 객체의 직렬화된 바이너리 표현 생성을 단순화합니다. 자세한 내용은 email.message를 참조하십시오.

문자열은 바이너리 데이터를 나타낼 수 없어서, Generator 클래스는 펼쳐지는 모든 메시지의 바이너리 데이터를 ASCII 호환 Content-Transfer_Encoding으로 변환하여 ASCII 호환 형식으로 변환해야 합니다. 전자 우편 RFC의 용어를 사용하면, 이를 “8비트 클린”이 아닌 I/O 스트림으로 직렬화하는 Generator로 생각할 수 있습니다. 즉, 대부분 응용 프로그램은 Generator가 아닌 BytesGenerator를 사용하려고 합니다.

class email.generator.Generator(outfp, mangle_from_=None, maxheaderlen=None, *, policy=None)

flatten() 메서드에 제공된 모든 메시지나 write() 메서드에 제공된 텍스트를 파일류 객체 outfp에 쓰는 Generator 객체를 반환합니다. outfp는 문자열 데이터를 받아들이는 write 메서드를 지원해야 합니다.

If optional mangle_from_ is True, put a > character in front of any line in the body that starts with the exact string "From ", that is From followed by a space at the beginning of a line. mangle_from_ defaults to the value of the mangle_from_ setting of the policy (which is True for the compat32 policy and False for all others). mangle_from_ is intended for use when messages are stored in Unix mbox format (see mailbox and WHY THE CONTENT-LENGTH FORMAT IS BAD [https://www.jwz.org/doc/content-length.html]).

maxheaderlen이 None이 아니면, maxheaderlen보다 긴 헤더 줄을 다시 접거나, 0이면 헤더를 다시 접지 않습니다. manheaderlen이 None(기본값)이면, policy 설정에 따라 헤더와 기타 메시지 줄을 줄 바꿈 합니다.

policy가 지정되면, 해당 정책을 사용하여 메시지 생성을 제어합니다. policy가 None(기본값)이면 flatten에 전달된 Message나 EmailMessage 객체와 연관된 정책을 사용하여 메시지 생성을 제어합니다. policy가 제어하는 것에 대한 자세한 내용은 email.policy를 참조하십시오.

버전 3.3에서 변경: policy 키워드를 추가했습니다.

버전 3.6에서 변경: mangle_from_과 maxheaderlen 매개 변수의 기본 동작은 정책을 따르는 것입니다.

flatten(msg, unixfrom=False, linesep=None)

msg를 루트로 하는 메시지 객체 구조의 텍스트 표현을 Generator 인스턴스가 만들어질 때 지정된 출력 파일에 인쇄합니다.

policy 옵션 cte_type이 8bit이면, 옵션이 7bit로 설정된 것처럼 메시지를 생성합니다. (문자열은 비 ASCII 바이트를 나타낼 수 없기 때문에 필요합니다.) 하이 비트가 설정된 모든 바이트를 ASCII 호환 Content-Transfer-Encoding을 사용하여 필요에 따라 변환합니다. 즉, 비 ASCII Content-Transfer-Encoding(Content-Transfer-Encoding: 8bit)을 갖는 파트를 ASCII 호환 Content-Transfer-Encoding으로 변환하고, 헤더에 있는 RFC 유효하지 않은 비 ASCII 바이트를 MIME unknown-8bit 문자 집합을 사용하여 인코딩하여, RFC 호환되게 만듭니다.

unixfrom이 True이면, 루트 메시지 객체의 첫 번째 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 헤더 앞에 유닉스 mailbox 형식(mailbox를 참조하십시오)에서 사용되는 봉투 헤더 구분자를 인쇄합니다. 루트 객체에 봉투 헤더가 없으면, 표준 헤더를 만듭니다. 기본값은 False입니다. 서브 파트의 경우 봉투 헤더가 인쇄되지 않음에 유의하십시오.

linesep이 None이 아니면, 펼쳐진 메시지의 모든 줄 사이의 구분자 문자로 사용합니다. linesep이 None(기본값)이면, policy에 지정된 값을 사용합니다.

버전 3.2에서 변경: 8bit 메시지 본문을 다시 인코딩하기 위한 지원과 linesep 인자가 추가되었습니다.

clone(fp)

정확히 같은 옵션을 갖고 fp를 새 outfp로 사용하는, 이 Generator 인스턴스의 독립 클론을 반환합니다.

write(s)

Generator의 생성자에 전달된 outfp의 write 메서드로 s를 씁니다. 이것은 print() 함수에서 사용될 Generator 인스턴스를 위해 딱 필요한 만큼의 파일류 API를 제공합니다.

편의상, EmailMessage는 as_string() 메서드와 str(aMessage)(일명 __str__())를 제공하여 메시지 객체의 포맷된 문자열 표현 생성을 단순화합니다. 자세한 내용은 email.message를 참조하십시오.

email.generator 모듈은 또한 파생 클래스인 DecodedGenerator를 제공하는데, Generator 베이스 클래스와 유사하지만, 비 text 파트는 직렬화되지 않고, 대신에 파트에 대한 정보로 채워진 템플릿에서 파생된 문자열로 출력 스트림에 표시됩니다.

class email.generator.DecodedGenerator(outfp, mangle_from_=None, maxheaderlen=None, fmt=None, *, policy=None)

Generator와 같이 작동하지만, Generator.flatten()에 전달된 메시지의 서브 파트에 대해, 서브 파트가 메인 유형이 text이면, 서브 파트의 디코딩된 페이 로드를 인쇄하고, 메인 유형이 text가 아니면, 그것을 인쇄하지 않고 파트 정보를 사용하여 문자열 fmt를 채운 후에 그 문자열을 인쇄합니다.

fmt를 채우기 위해, fmt % part_info를 실행하는데, 여기서 part_info는 다음 키와 값으로 구성된 딕셔너리입니다:

type – text가 아닌 파트의 전체 MIME 유형

maintype – text가 아닌 파트의 메인 MIME 유형

subtype – text가 아닌 파트의 서브 MIME 유형

filename – text가 아닌 파트의 파일명

description – text가 아닌 파트와 관련된 설명

encoding – text가 아닌 파트의 콘텐츠 전송 인코딩(Content transfer encoding)

fmt가 None이면, 다음 기본 fmt를 사용합니다:

“[Non-text (%(type)s) part of message omitted, filename %(filename)s]”

선택적 _mangle_from_ 및 maxheaderlen은 Generator 베이스 클래스와 같습니다.

각주

[1]

This statement assumes that you use the appropriate setting for unixfrom, and that there are no email.policy settings calling for automatic adjustments (for example, refold_source must be none, which is not the default). It is also not 100% true, since if the message does not conform to the RFC standards occasionally information about the exact original text is lost during parsing error recovery. It is a goal to fix these latter edge cases when possible.

email.policy: Policy Objects

Added in version 3.3.

소스 코드: Lib/email/policy.py [https://github.com/python/cpython/tree/main/Lib/email/policy.py]

email 패키지의 주요 초점은 다양한 전자 우편과 MIME RFC에 설명된 대로 전자 우편 메시지를 처리하는 것입니다. 그러나 전자 우편 메시지의 일반적인 형식(각각 이름, 콜론, 값 순으로 구성된 헤더 필드의 블록, 빈 줄과 임의의 ‘본문’ 이 뒤따르는 전체 블록)은 전자 우편 영역 밖에서도 용도가 발견되는 형식입니다. 이러한 용도 중 일부는 메인 전자 우편 RFC와 상당히 유사하지만, 일부는 그렇지 않습니다. 전자 우편으로 작업할 때에도, RFC의 엄격한 준수를 위반하는 것이 바람직할 때가 있습니다. 가령 표준을 따르지 않는 전자 우편 서버와 상호 운영되거나 표준을 위반하는 방식으로 사용하기 원하는 확장을 구현하는 전자 우편을 생성하는 경우가 그렇습니다.

정책 객체는 email 패키지에 이러한 개별 사용 사례를 모두 처리 할 수 있는 유연성을 제공합니다.

Policy 객체는 사용 중에 email 패키지의 다양한 구성 요소 동작을 제어하는 일련의 어트리뷰트와 메서드를 캡슐화합니다. Policy 인스턴스는 email 패키지의 다양한 클래스와 메서드로 전달되어 기본 동작을 변경할 수 있습니다. 설정 가능한 값과 기본값은 아래에 설명되어 있습니다.

email 패키지의 모든 클래스에서 사용되는 기본 정책이 있습니다. 모든 parser 클래스와 관련 편의 함수 및 Message 클래스의 경우, 이것은 사전 정의된 인스턴스 compat32를 통한 Compat32 정책입니다. 이 정책은 파이썬 3.3 이전 버전의 email 패키지와 완전한 과거 호환성(어떤 경우에는, 버그 호환성을 포함합니다)을 제공합니다.

EmailMessage에 대한 policy 키워드의 기본값은 사전 정의된 인스턴스 default를 통한 EmailPolicy 정책입니다.

Message나 EmailMessage 객체가 만들어질 때, 정책을 획득합니다. 메시지가 parser로 만들어지면, 구문 분석기에 전달된 정책이 만들어지는 메시지가 사용하는 정책이 됩니다. 프로그램이 메시지를 만들면, 만들 때 정책을 지정할 수 있습니다. 메시지가 generator에 전달될 때, 제너레이터는 기본적으로 메시지의 정책을 사용하지만, 특정 정책을 제너레이터에 전달하여 메시지 객체에 저장된 정책을 재정의할 수도 있습니다.

email.parser 클래스와 구문 분석기 편의 함수에 대한 policy 키워드의 기본값은 이후 버전의 파이썬에서 변경될 예정입니다. 따라서 parser 모듈에서 설명된 클래스와 함수를 호출할 때는 항상 사용할 정책을 명시적으로 지정해야 합니다.

이 설명서의 첫 부분은 compat32를 포함한 모든 정책 객체에 공통적인 기능을 정의하는 추상 베이스 클래스 인 Policy의 기능을 다룹니다. 여기에는 email 패키지에 의해 내부적으로 호출되는 특정 훅 메서드가 포함되며, 사용자 정의 정책은 다른 동작을 얻기 위해 재정의할 수 있습니다. 두 번째 부분에서는 표준 동작과 이전 버전과 호환되는 동작과 기능을 각각 제공하는 훅을 구현하는 구상 클래스 EmailPolicy와 Compat32를 설명합니다.

Policy 인스턴스는 불변이지만, 복제할 수 있는데, 클래스 생성자와 같은 키워드 인자를 받아들이고 원본의 사본이지만 지정된 어트리뷰트 값이 변경된 새 Policy 인스턴스를 반환합니다.

예를 들어, 다음 코드를 사용하여 디스크의 파일에서 전자 우편 메시지를 읽고 유닉스 시스템의 시스템 sendmail 프로그램으로 전달할 수 있습니다:

>>> from email import message_from_binary_file
>>> from email.generator import BytesGenerator
>>> from email import policy
>>> from subprocess import Popen, PIPE
>>> with open('mymsg.txt', 'rb') as f:
...     msg = message_from_binary_file(f, policy=policy.default)
...
>>> p = Popen(['sendmail', msg['To'].addresses[0]], stdin=PIPE)
>>> g = BytesGenerator(p.stdin, policy=msg.policy.clone(linesep='\r\n'))
>>> g.flatten(msg)
>>> p.stdin.close()
>>> rc = p.wait()

여기서 우리는 BytesGenerator에게 sendmail의 stdin으로 공급할 바이너리 문자열을 만들 때 RFC 올바른 줄 구분자 문자를 사용하도록 지시합니다. 기본 정책은 \n 줄 구분자를 사용합니다.

일부 email 패키지 메서드는 policy 키워드 인자를 받아들여, 해당 메서드에 대한 정책을 대체 할 수 있도록 합니다. 예를 들어, 다음 코드는 이전 예제의 msg 객체의 as_bytes() 메서드를 사용하고 실행 중인 플랫폼의 기본 줄 구분자를 사용하여 메시지를 파일에 씁니다:

>>> import os
>>> with open('converted.txt', 'wb') as f:
...     f.write(msg.as_bytes(policy=msg.policy.clone(linesep=os.linesep)))
17

더하기 연산자를 사용하여 정책 객체를 결합하여, 기본값이 아닌 설정이 합쳐진 조합으로 설정된 정책 객체를 생성할 수도 있습니다:

>>> compat_SMTP = policy.compat32.clone(linesep='\r\n')
>>> compat_strict = policy.compat32.clone(raise_on_defect=True)
>>> compat_strict_SMTP = compat_SMTP + compat_strict

이 연산은 교환적(commutative)이지 않습니다; 즉, 객체가 더해지는 순서가 중요합니다. 예시하면 이렇습니다:

>>> policy100 = policy.compat32.clone(max_line_length=100)
>>> policy80 = policy.compat32.clone(max_line_length=80)
>>> apolicy = policy100 + policy80
>>> apolicy.max_line_length
80
>>> apolicy = policy80 + policy100
>>> apolicy.max_line_length
100

class email.policy.Policy(**kw)

모든 정책 클래스의 추상 베이스 클래스입니다. 불변 속성, clone() 메서드 및 생성자 시맨틱의 구현뿐만 아니라 몇 가지 간단한 메서드에 대한 기본 구현을 제공합니다.

정책 클래스의 생성자에는 다양한 키워드 인자가 전달될 수 있습니다. 지정할 수 있는 인자는 이 클래스의 메서드 이외의 프로퍼티, 그리고 구상 클래스의 메서드 이외의 프로퍼티입니다. 생성자에 지정된 값은 해당 어트리뷰트의 기본값을 재정의합니다.

이 클래스는 다음 프로퍼티를 정의합니다. 따라서, 모든 정책 클래스의 생성자에 다음에 대한 값이 전달될 수 있습니다:

max_line_length

줄 종료 문자를 포함하지 않고, 직렬화된 출력에서 줄의 최대 길이. RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]에 따라 기본값은 78입니다. 0이나 None 값은 줄 바꿈을 전혀 수행하지 않아야 함을 나타냅니다.

linesep

직렬화된 출력에서 줄을 종료하는 데 사용되는 문자열입니다. RFC는 \r\n을 요구하지만, 기본값은 파이썬에서 사용하는 내부 줄 종료 규칙을 따라 \n입니다.

cte_type

사용해야 하는 콘텐츠 전송 인코딩(Content Transfer Encoding) 유형을 제어합니다. 가능한 값은 다음과 같습니다:

7bit

모든 데이터는 “7비트 클린”(ASCII 전용)이어야 합니다. 즉, 필요하면 quoted-printable이나 base64 인코딩을 사용하여 데이터를 인코딩합니다.

8bit

데이터는 7비트 클린으로 제한되지 않습니다. 헤더의 데이터는 여전히 ASCII 전용이어야 하므로 인코딩되지만 (예외는 아래 fold_binary()와 utf8을 참조하십시오), 본문 부분은 8bit CTE를 사용할 수 있습니다.

8bit cte_type 값은 문자열이 바이너리 데이터를 포함할 수 없어서 Generator가 아닌 BytesGenerator에서만 작동합니다. Generator가 cte_type=8bit를 지정하는 정책에 따라 작동하면, cte_type이 7bit인 것처럼 동작합니다.

raise_on_defect

True이면, 만나는 모든 결함을 에러로 발생시킵니다. False(기본값)이면, 결함은 register_defect() 메서드로 전달됩니다.

mangle_from_

True이면, 본문에서 “From “으로 시작하는 줄은 >를 앞에 배치하여 이스케이프 됩니다. 이 매개 변수는 제너레이터가 메시지를 직렬화할 때 사용됩니다. 기본값: False.

Added in version 3.5.

message_factory

새로운 빈 메시지 객체를 생성하기 위한 팩토리 함수. 메시지를 구축할 때 구분 분석기가 사용합니다. 기본값은 None이며, 이때 Message가 사용됩니다.

Added in version 3.6.

verify_generated_headers

If True (the default), the generator will raise HeaderWriteError instead of writing a header that is improperly folded or delimited, such that it would be parsed as multiple headers or joined with adjacent data. Such headers can be generated by custom header classes or bugs in the email module.

As it’s a security feature, this defaults to True even in the Compat32 policy. For backwards compatible, but unsafe, behavior, it must be set to False explicitly.

Added in version 3.13.

다음 Policy 메서드는 email 라이브러리를 사용하여 사용자 정의 설정으로 정책 인스턴스를 만드는 코드가 호출하기 위한 것입니다:

clone(**kw)

키워드 인자로 새로운 값이 부여되는 어트리뷰트를 제외하고, 어트리뷰트가 현재 인스턴스와 같은 값을 갖는 새로운 Policy 인스턴스를 반환합니다.

나머지 Policy 메서드는 email 패키지 코드에 의해 호출되며, email 패키지를 사용하는 응용 프로그램에 의해 호출되는 용도가 아닙니다. 사용자 정의 정책은 이 모든 메서드를 구현해야 합니다.

handle_defect(obj, defect)

obj에서 찾은 defect를 처리합니다. email 패키지가 이 메서드를 호출할 때, defect는 항상 Defect의 서브 클래스입니다.

기본 구현은 raise_on_defect 플래그를 확인합니다. True이면, defect가 예외로 발생합니다. False(기본값)이면 obj와 defect가 register_defect()로 전달됩니다.

register_defect(obj, defect)

obj에 defect를 등록합니다. email 패키지에서, defect는 항상 Defect의 서브 클래스입니다.

기본 구현은 obj의 defects 어트리뷰트의 append 메서드를 호출합니다. email 패키지가 handle_defect를 호출할 때, obj는 일반적으로 append 메서드가 있는 defects 어트리뷰트가 있습니다. email 패키지와 함께 사용되는 사용자 정의 객체 형(예를 들어, 사용자 정의 Message 객체)도 이러한 어트리뷰트를 제공해야 합니다, 그렇지 않으면 구문 분석된 메시지의 결함이 예기치 않은 에러를 발생시킵니다.

header_max_count(name)

name이라는 헤더의 최대 허용 개수를 반환합니다.

헤더가 EmailMessage나 Message 객체에 추가될 때 호출됩니다. 반환 값이 0이나 None이 아니고, 반환 값보다 크거나 같은 수의 이름이 name인 헤더가 이미 있으면 ValueError가 발생합니다.

Message.__setitem__의 기본 동작은 값을 헤더 리스트에 추가하는 것이므로, 깨닫지 못하는 사이에 중복 헤더를 만들기 쉽습니다. 이 메서드는 특정 헤더를 Message에 프로그래밍 방식으로 추가할 수 있는 인스턴스의 수를 제한할 수 있도록 합니다. (이 제약은 구문 분석기가 보지 않습니다, 구문 분석기는 구문 분석 중인 메시지에 존재하는 수 만큼 헤더를 충실하게 생성합니다.)

기본 구현은 모든 헤더 이름에 대해 None을 반환합니다.

header_source_parse(sourcelines)

email 패키지는 문자열 리스트로 이 메서드를 호출하며, 각 문자열은 구문 분석 중인 소스에서 발견된 줄 구분 문자로 끝납니다. 첫 번째 줄에는 필드 헤더 이름과 구분자가 포함됩니다. 소스의 모든 공백이 유지됩니다. 이 메서드는 구문 분석된 헤더를 나타내기 위해 Message에 저장될 (name, value) 튜플을 반환해야 합니다.

구현이 기존 email 패키지 정책과의 호환성을 유지하기 원한다면, name은 대소 문자를 유지한 이름( ‘:’ 구분자까지의 모든 문자)이어야 하지만, value는 선행 공백이 제거되고 펼쳐진(unfolded) 값(모든 줄 구분자 문자는 제거하지만, 공백은 그대로 유지한)이어야 합니다.

sourcelines는 서로게이트 이스케이프 된 바이너리 데이터를 포함할 수 있습니다.

기본 구현이 없습니다

header_store_parse(name, value)

email 패키지는 (구문 분석기가 만든 Message가 아니라) 응용 프로그램이 Message를 프로그래밍 방식으로 수정할 때, 응용 프로그램이 제공한 name과 value로 이 메서드를 호출합니다. 이 메서드는 헤더를 나타내기 위해 Message에 저장될 (name, value) 튜플을 반환해야 합니다.

구현이 기존 email 패키지 정책과의 호환성을 유지하기 원한다면, name과 value는 전달된 인자의 내용을 변경하지 않는 문자열이나 문자열의 서브 클래스여야 합니다.

기본 구현이 없습니다

header_fetch_parse(name, value)

email 패키지는 응용 프로그램이 해당 헤더를 요청할 때 Message에 현재 저장된 name과 value로 이 메서드를 호출하며, 메서드가 반환하는 것은 꺼내는 헤더의 값으로 응용 프로그램에 다시 전달됩니다. Message에 같은 이름을 가진 헤더가 두 개 이상 있을 수 있음에 유의하십시오; 이 메서드로는 응용 프로그램으로 반환될 헤더의 특정 이름과 값이 전달됩니다.

value는 서로게이트 이스케이프 된 바이너리 데이터를 포함할 수 있습니다. 이 메서드가 반환하는 값에는 서로게이트 이스케이프 된 바이너리 데이터가 없어야 합니다.

기본 구현이 없습니다

fold(name, value)

email 패키지는 지정된 헤더에 대해 Message에 현재 저장된 name과 value로 이 메서드를 호출합니다. 이 메서드는 name을 value와 합치고 적절한 위치에 linesep 문자를 삽입하여 (정책 설정에 따라) 올바르게 “접힌(folded)” 헤더를 나타내는 문자열을 반환해야 합니다. 전자 우편 헤더 접기 규칙에 대한 설명은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]를 참조하십시오.

value는 서로게이트 이스케이프 된 바이너리 데이터를 포함할 수 있습니다. 메서드가 반환한 문자열에는 서로게이트 이스케이프 된 바이너리 데이터가 없어야 합니다.

fold_binary(name, value)

반환 값이 문자열이 아니라 바이트열 객체여야 한다는 점을 제외하고는 fold()와 같습니다.

value는 서로게이트 이스케이프 된 바이너리 데이터를 포함할 수 있습니다. 이들은 반환된 바이트열 객체에서 바이너리 데이터로 다시 변환될 수 있습니다.

class email.policy.EmailPolicy(**kw)

이 구상 Policy는 현재 전자 우편 RFC를 완전히 준수하기 위한 동작을 제공합니다. 여기에는 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html], RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 및 현재 MIME RFC가 포함되지만 이에 국한되지는 않습니다.

이 정책은 새로운 헤더 구문 분석과 접기(folding) 알고리즘을 추가합니다. 단순한 문자열 대신, 헤더는 필드 유형에 따라 달라지는 어트리뷰트를 가진 str 서브 클래스입니다. 구문 분석과 접기 알고리즘은 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html]과 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]를 완전히 구현합니다.

message_factory 어트리뷰트의 기본값은 EmailMessage입니다.

모든 정책에 적용되는 위에 나열된 설정 가능 어트리뷰트 외에도, 이 정책은 다음과 같은 어트리뷰트를 추가합니다:

Added in version 3.6: [1]

utf8

False이면, RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]를 따르고 헤더에서 ASCII가 아닌 문자를 “인코딩된 단어”로 인코딩하여 지원합니다. True이면, RFC 6532 [https://datatracker.ietf.org/doc/html/rfc6532.html]를 따르고 헤더에 utf-8 인코딩을 사용합니다. 이러한 방식으로 포맷된 메시지는 SMTPUTF8 확장(RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html])을 지원하는 SMTP 서버로 전달될 수 있습니다.

refold_source

Message 객체의 헤더 값이 (프로그램이 설정하는 것과 대조적으로) parser에서 온 것이면, 이 어트리뷰트는 메시지를 직렬화된 형식으로 다시 변환할 때 제너레이터가 그 값을 다시 접어야 하는지를 나타냅니다. 가능한 값은 다음과 같습니다:

none

모든 소스 값은 원래 접기를 사용합니다

long

max_line_length보다 긴 줄이 있는 소스 값은 다시 접힙니다.

all

모든 값이 다시 접힙니다.

기본값은 long입니다.

header_factory

name과 value 두 개의 인자를 취하는 콜러블. 여기서 name은 헤더 필드 이름이고 value는 펼쳐진 헤더 필드 값이며 해당 헤더를 나타내는 문자열 서브 클래스를 반환합니다. 다양한 주소와 날짜 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 헤더 필드 유형과 주요 MIME 헤더 필드 유형에 대한 사용자 정의 구문 분석을 지원하는 기본 header_factory(headerregistry를 참조하십시오)가 제공됩니다. 향후 추가 사용자 정의 구문 분석에 대한 지원이 추가될 것입니다.

content_manager

적어도 두 개의 메서드가 있는 객체: get_content와 set_content. EmailMessage 객체의 get_content()나 set_content() 메서드가 호출될 때, 이 객체의 해당 메서드를 호출하는데, 메시지 객체를 첫 번째 인자로 전달하고 전달된 다른 인자와 키워드를 추가 인자로 전달합니다. 기본적으로 content_manager는 raw_data_manager로 설정됩니다.

Added in version 3.4.

이 클래스는 다음과 같은 Policy의 추상 메서드의 구상 구현을 제공합니다:

header_max_count(name)

지정된 이름의 헤더를 나타내는 데 사용되는 특수화된 클래스의 max_count 어트리뷰트 값을 반환합니다.

header_source_parse(sourcelines)

이름은 ‘:'까지의 모든 것으로 구문 분석되고 수정되지 않은 상태로 반환됩니다. 값은 첫 번째 줄의 나머지 부분에서 선행 공백을 제거한 후에 모든 후속 줄을 이어붙이고 후행 캐리지 리턴이나 줄 바꿈 문자를 제거하여 결정됩니다.

header_store_parse(name, value)

이름은 변경되지 않고 반환됩니다. 입력값에 name 어트리뷰트가 있고 대소 문자를 무시하고 name과 일치하면, 값은 변경되지 않고 반환됩니다. 그렇지 않으면 name과 value는 header_factory로 전달되고, 결과 헤더 객체가 값으로 반환됩니다. 이 경우 입력값에 CR이나 LF 문자가 포함되어 있으면 ValueError가 발생합니다.

header_fetch_parse(name, value)

값에 name 어트리뷰트가 있으면, 수정되지 않은 상태로 반환됩니다. 그렇지 않으면 name과 CR이나 LF 문자가 제거된 value가 header_factory로 전달되고, 결과 헤더 객체가 반환됩니다. 서로게이트 이스케이프 된 바이트열은 유니코드 알 수 없는 문자 글리프(unknown-character glyph)로 바뀝니다.

fold(name, value)

헤더 접기는 refold_source 정책 설정에 의해 제어됩니다. 값은 name 어트리뷰트가 없을 때, 그리고 그때만 ‘소스값’으로 간주합니다 (name 어트리뷰트가 있다는 것은 헤더 객체나 그 일종이라는 뜻입니다). 정책에 따라 소스값을 다시 접어야 할 필요가 있으면, header_factory에 name과 CR과 LF 문자가 제거된 value를 전달하여 헤더 객체로 변환됩니다. 헤더 객체의 접기는 현재 정책으로 fold 메서드를 호출하여 수행됩니다.

소스값은 splitlines()를 사용하여 줄로 분할됩니다. 값을 다시 접지 않으면, 정책의 linesep을 사용하여 줄을 다시 이어붙인 후에 반환합니다. ASCII가 아닌 바이너리 데이터가 포함된 줄은 예외입니다. 이 경우 refold_source 설정과 관계없이 값이 다시 접히는데, unknown-8bit 문자 집합을 사용하여 바이너리 데이터가 CTE로 인코딩됩니다.

fold_binary(name, value)

cte_type이 7bit이면, 반환된 값이 바이트열인 것을 제외하고 fold()와 같습니다.

cte_type이 8bit이면, ASCII가 아닌 바이너리 데이터는 다시 바이트열로 변환됩니다. 바이너리 데이터가 단일 바이트 문자와 멀티 바이트 문자 중 어는 것으로 구성되어 있는지 알 방법이 없어서, refold_header 설정과 관계없이 바이너리 데이터가 있는 헤더는 다시 접히지 않습니다.

다음 EmailPolicy 인스턴스는 특정 응용 프로그램 도메인에 적합한 기본값을 제공합니다. 향후 이러한 인스턴스들(특히 HTTP 인스턴스)의 동작은 그 들의 도메인과 관련된 RFC에 훨씬 더 가깝게 조정될 수 있음에 유의하십시오.

email.policy.default

모든 기본값이 변경되지 않은 EmailPolicy 인스턴스. 이 정책은 RFC 올바른 \r\n이 아닌 표준 파이썬 \n 줄 종료를 사용합니다.

email.policy.SMTP

전자 우편 RFC를 준수하도록 메시지를 직렬화하는 데 적합합니다. default와 유사하지만, linesep이 \r\n으로 설정되어 RFC를 준수합니다.

email.policy.SMTPUTF8

utf8가 True라는 점을 제외하고, SMTP와 같습니다. 헤더에 인코딩된 단어를 사용하지 않고 메시지를 메시지 저장소로 직렬화하는 데 유용합니다. SMTP 전송에는 발신자나 수신자 주소에 ASCII가 아닌 문자가 있을 때만 사용해야 합니다 (smtplib.SMTP.send_message() 메서드는 이를 자동으로 처리합니다).

email.policy.HTTP

HTTP 트래픽에 사용하기 위해 헤더를 직렬화하는 데 적합합니다. max_line_length가 None(무제한)으로 설정된 것을 제외하고, SMTP와 유사합니다.

email.policy.strict

편의 인스턴스. raise_on_defect가 True로 설정된 것을 제외하고, default와 같습니다. 다음과 같이 작성하여 모든 정책을 엄격하게 만들 수 있도록 합니다:

somepolicy + policy.strict

이러한 모든 EmailPolicy를 통해, email 패키지의 효과적인 API가 다음과 같은 방식으로 파이썬 3.2 API에서 변경됩니다:

Message에서 헤더를 설정하면 해당 헤더가 구문 분석되고 헤더 객체가 만들어집니다.

Message에서 헤더 값을 가져오면 해당 헤더가 구문 분석되고 헤더 객체가 만들어져 반환됩니다.

모든 헤더 객체나 정책 설정으로 인해 다시 접힌 모든 헤더는 인코딩된 단어가 필요한 위치와 허용되는 위치를 포함하여 RFC 접기 알고리즘을 완전히 구현하는 알고리즘을 사용하여 접힙니다.

응용 프로그램의 시각에서, 이것은 EmailMessage를 통해 얻은 모든 헤더가 추가 어트리뷰트가 있는 헤더 객체이며, 그것의 문자열 값은 헤더의 완전히 디코딩된 유니코드 값이 됨을 뜻합니다. 마찬가지로, 유니코드 문자열을 사용하여 헤더에 새 값이나 새로 만들어진 헤더를 대입할 수 있으며, 정책은 유니코드 문자열을 올바른 RFC 인코딩 형식으로 변환합니다.

헤더 객체와 그들의 어트리뷰트는 headerregistry에 설명되어 있습니다.

class email.policy.Compat32(**kw)

이 구상 Policy는 과거 호환성 정책입니다. 파이썬 3.2에 있는 email 패키지의 동작을 흉내 냅니다. policy 모듈은 이 클래스의 인스턴스 compat32도 정의하고, 기본 정책으로 사용합니다. 따라서 email 패키지의 기본 동작은 파이썬 3.2와의 호환성을 유지하는 것입니다.

다음 어트리뷰트는 Policy 기본값과 다른 값을 갖습니다:

mangle_from_

기본값은 True입니다.

이 클래스는 다음과 같은 Policy의 추상 메서드의 구상 구현을 제공합니다:

header_source_parse(sourcelines)

이름은 ‘:'까지의 모든 것으로 구문 분석되고 수정되지 않은 상태로 반환됩니다. 값은 첫 번째 줄의 나머지 부분에서 선행 공백을 제거한 후에 모든 후속 줄을 이어붙이고 후행 캐리지 리턴이나 줄 바꿈 문자를 제거하여 결정됩니다.

header_store_parse(name, value)

이름과 값은 수정되지 않은 상태로 반환됩니다.

header_fetch_parse(name, value)

값에 바이너리 데이터가 포함되어 있으면, unknown-8bit 문자 집합을 사용하여 Header 객체로 변환됩니다. 그렇지 않으면 수정되지 않은 상태로 반환됩니다.

fold(name, value)

Header 접기 알고리즘을 사용하여 헤더를 접습니다. 이 알고리즘은 값의 기존 줄 바꿈을 유지하고, 각 결과 줄을 max_line_length로 줄 넘김 합니다. ASCII가 아닌 바이너리 데이터는 unknown-8bit 문자 집합을 사용하여 CTE 인코딩됩니다.

fold_binary(name, value)

Header 접기 알고리즘을 사용하여 헤더를 접습니다. 이 알고리즘은 값의 기존 줄 바꿈을 유지하고, 각 결과 줄을 max_line_length로 줄 넘김 합니다. cte_type이 7bit이면, ASCII가 아닌 바이너리 데이터는 unknown-8bit 문자 집합을 사용하여 CTE 인코딩됩니다. 그렇지 않으면 원본 소스 헤더가 사용되는데, 기존 줄 바꿈과 임의의 (RFC 유효하지 않은) 바이너리 데이터가 포함될 수 있습니다.

email.policy.compat32

파이썬 3.2 email 패키지 동작과의 호환성을 제공하는 Compat32의 인스턴스.

각주

[1]

원래 3.3에 잠정적 기능으로 추가되었습니다.

email.errors: Exception and Defect classes

소스 코드: Lib/email/errors.py [https://github.com/python/cpython/tree/main/Lib/email/errors.py]

email.errors 모듈에는 다음과 같은 예외 클래스가 정의되어 있습니다:

exception email.errors.MessageError

이것은 email 패키지가 발생시킬 수 있는 모든 예외의 베이스 클래스입니다. 표준 Exception 클래스에서 파생되며 추가 메서드를 정의하지 않습니다.

exception email.errors.MessageParseError

이것은 Parser 클래스에서 발생하는 예외의 베이스 클래스입니다. MessageError에서 파생됩니다. 이 클래스는 headerregistry에서 사용하는 구문 분석기에서도 내부적으로 사용됩니다.

exception email.errors.HeaderParseError

메시지의 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 헤더를 구문 분석할 때 일부 에러 조건에서 발생합니다. 이 클래스는 MessageParseError에서 파생됩니다. 메서드가 호출될 때 콘텐츠 유형을 알 수 없으면, set_boundary() 메서드는 이 에러를 발생시킵니다. Header는 특정 base64 디코딩 에러와 내장된 헤더를 포함하는 것으로 보이는 헤더를 만들려고 할 때 (즉, 연장 줄(continuation line)이어야 할 곳에 선행 공백이 없고 헤더처럼 보이는 것이 있을 때) 이 에러를 발생시킬 수 있습니다.

exception email.errors.BoundaryError

폐지되었고 더는 사용되지 않습니다.

exception email.errors.MultipartConversionError

add_payload()를 사용하여 페이 로드가 Message 객체에 추가되었지만, 페이 로드가 이미 스칼라(scalar)이고 메시지의 Content-Type 메인 유형이 multipart도 아니고 누락되지도 않았으면 발생합니다. MultipartConversionError는 MessageError와 내장 TypeError에서 다중 상속됩니다.

Message.add_payload()는 폐지되었으므로, 실제로 이 예외는 거의 발생하지 않습니다. 그러나 MIMENonMultipart에서 파생된 클래스(예를 들어 MIMEImage)의 인스턴스에서 attach() 메서드를 호출하면 예외가 발생할 수도 있습니다.

exception email.errors.HeaderWriteError

Raised when an error occurs when the generator outputs headers.

exception email.errors.MessageDefect

This is the base class for all defects found when parsing email messages. It is derived from ValueError.

exception email.errors.HeaderDefect

This is the base class for all defects found when parsing email headers. It is derived from MessageDefect.

다음은 메시지를 구문 분석하는 동안 FeedParser가 찾을 수 있는 결함 목록입니다. 문제가 발견된 메시지에 결함이 추가됨에 유의하십시오. 그래서, 예를 들어, multipart/alternative 내에 중첩된 메시지에 잘못된 헤더가 있으면, 해당 중첩 메시지 객체가 결함을 갖게 되지만 포함하는 메시지는 그렇지 않습니다.

모든 결함 클래스는 email.errors.MessageDefect의 서브 클래스입니다.

NoBoundaryInMultipartDefect – 메시지가 멀티 파트라고 주장했지만, boundary 파라미터가 없습니다.

StartBoundaryNotFoundDefect – Content-Type 헤더에서 주장하는 시작 경계를 찾지 못했습니다.

CloseBoundaryNotFoundDefect – 시작 경계가 발견되었지만, 해당하는 종료 경계가 발견되지 않았습니다.

Added in version 3.3.

FirstHeaderLineIsContinuationDefect – 메시지의 첫 번째 헤더 줄에 연장 줄(continuation line)이 있습니다.

MisplacedEnvelopeHeaderDefect - 헤더 블록 중간에 “Unix From” 헤더가 있습니다.

MissingHeaderBodySeparatorDefect - 헤더를 구문 분석하는 중에 선행 공백이 없지만 ‘:’ 가 포함되지 않은 줄이 발견되었습니다. 그 줄이 본문의 첫 번째 줄을 나타내는 것으로 가정하여 구문 분석이 계속됩니다.

Added in version 3.3.

MalformedHeaderDefect – 콜론이 없거나 다른 식으로 잘못된 헤더가 발견되었습니다.

버전 3.3부터 폐지됨: 이 결함은 여러 파이썬 버전에서 사용되지 않았습니다.

MultipartInvariantViolationDefect – 메시지가 multipart라고 주장했지만, 서브 파트가 없습니다. 메시지에 이 결함이 있으면, 콘텐츠 유형이 multipart라고 주장하더라도 is_multipart() 메서드는 False를 반환할 수 있음에 유의하십시오.

InvalidBase64PaddingDefect – base64로 인코딩된 바이트열 블록을 디코딩할 때, 패딩이 올바르지 않습니다. 디코딩을 수행하기 위해 충분한 패딩이 추가되지만, 바이트열을 디코딩한 결과는 유효하지 않을 수 있습니다.

InvalidBase64CharactersDefect – base64로 인코딩된 바이트열 블록을 디코딩할 때, base64 알파벳 이외의 문자가 발견되었습니다. 문자는 무시되지만, 바이트열을 디코딩한 결과는 유효하지 않을 수 있습니다.

InvalidBase64LengthDefect – base64로 인코딩된 바이트열 블록을 디코딩할 때, 비 패딩 base64 문자 수가 유효하지 않습니다 (4의 배수보다 1이 큽니다). 인코딩된 블록은 그대로 유지됩니다.

InvalidDateDefect – When decoding an invalid or unparsable date field. The original value is kept as-is.

email.headerregistry: Custom Header Objects

소스 코드: Lib/email/headerregistry.py [https://github.com/python/cpython/tree/main/Lib/email/headerregistry.py]

Added in version 3.6: [1]

헤더는 str의 사용자 정의된 서브 클래스로 표현됩니다. 주어진 헤더를 표현하는 데 사용되는 특정 클래스는 헤더가 만들어질 때 policy의 header_factory에 의해 결정됩니다. 이 섹션에서는 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 호환 전자 우편 메시지를 처리하기 위해 email 패키지가 구현한 특정 header_factory에 관해 설명합니다. 다양한 헤더 유형에 대해 사용자 정의된 헤더 객체를 제공할 뿐만 아니라, 응용 프로그램에서 고유한 사용자 정의 헤더 유형을 추가할 수 있는 확장 메커니즘을 제공합니다.

EmailPolicy에서 파생된 정책 객체를 사용할 때, 모든 헤더는 HeaderRegistry가 생성하며 마지막 베이스 클래스로 BaseHeader를 갖습니다. 각 헤더 클래스에는 헤더 유형에 따라 결정되는 추가 베이스 클래스가 있습니다. 예를 들어, 많은 헤더에는 다른 베이스 클래스로 UnstructuredHeader 클래스를 갖습니다. 헤더의 특수화된 두 번째 클래스는 HeaderRegistry에 저장된 검색 테이블을 사용하여 헤더의 이름으로 결정됩니다. 이 모든 것은 일반적인 응용 프로그램에 대해 투명하게 관리되지만, 더욱 복잡한 응용 프로그램에서 사용할 수 있도록 기본 동작을 수정하기 위한 인터페이스가 제공됩니다.

아래 섹션은 먼저 헤더 베이스 클래스와 그들의 어트리뷰트를, 그다음으로 HeaderRegistry의 동작을 수정하기 위한 API를, 그리고 마지막으로 구조화된 헤더에서 구문 분석된 데이터를 나타내는 데 사용되는 지원 클래스에를 설명합니다.

class email.headerregistry.BaseHeader(name, value)

name과 value는 header_factory 호출에서 BaseHeader로 전달됩니다. 헤더 객체의 문자열 값은 유니코드로 완전히 디코딩된 value입니다.

이 베이스 클래스는 다음과 같은 읽기 전용 프로퍼티를 정의합니다:

name

헤더 이름(‘:’ 앞의 필드 부분). 이것은 정확히 header_factory 호출에 전달된 name에 대한 값입니다; 즉, 대소 문자가 유지됩니다.

defects

구문 분석 중 발견된 RFC 준수 문제를 보고하는 HeaderDefect 인스턴스 튜플. email 패키지는 규정 준수 문제 감지에 대해 완전해지려고 합니다. 보고될 수 있는 결함 유형에 대한 설명은 errors 모듈을 참조하십시오.

max_count

같은 name을 가질 수 있는 이 유형의 최대 헤더 수. None 값은 무제한을 의미합니다. 이 어트리뷰트의 BaseHeader 값은 None입니다; 특수화된 헤더 클래스가 필요할 때 이 값을 재정의할 것으로 기대됩니다.

BaseHeader는 또한 email 라이브러리 코드에 의해 호출되고 일반적으로 응용 프로그램이 호출해서는 안 되는 다음 메서드를 제공합니다:

fold(*, policy)

policy에 따라 헤더를 올바르게 접는 데 필요한 linesep 문자를 포함하는 문자열을 반환합니다. 헤더는 임의의 바이너리 데이터를 포함할 수 없어서, 8bit의 cte_type은 마치 7bit인 것처럼 처리됩니다. utf8이 False이면, 비 ASCII 데이터는 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html]로 인코딩됩니다.

BaseHeader 자체는 헤더 객체를 만드는 데 사용할 수 없습니다. 헤더 객체를 생성하기 위해 각 특수화된 헤더가 협력하는 프로토콜을 정의합니다. 특히 BaseHeader는 특수화된 클래스가 parse라는 classmethod()를 제공할 것을 요구합니다. 이 메서드는 다음과 같이 호출됩니다:

parse(string, kwds)

kwds는 하나의 미리 초기화된 키 defects를 포함하는 딕셔너리입니다. defects는 빈 리스트입니다. parse 메서드는 감지된 결함을 이 리스트에 추가해야 합니다. 반환될 때, kwds 딕셔너리는 반드시 적어도 키 decoded와 defects에 대한 값을 포함해야 합니다. decoded는 헤더의 문자열 값이어야 합니다 (즉, 유니코드로 완전히 디코딩된 헤더 값). parse 메서드는 string이 콘텐츠 전송 인코딩된 파트를 포함할 수 있다고 가정해야 하지만, 인코딩되지 않은 헤더 값을 구문 분석할 수 있도록 모든 유효한 유니코드 문자도 올바르게 처리해야 합니다.

BaseHeader의 __new__는 헤더 인스턴스를 만들고, init 메서드를 호출합니다. 특수화된 클래스가 BaseHeader 자체에서 제공하는 것 이상의 추가 어트리뷰트를 설정하려면 init 메서드 만 제공하면 됩니다. 이러한 init 메서드는 다음과 같아야 합니다:

def init(self, /, *args, **kw):
    self._myattr = kw.pop('myattr')
    super().init(*args, **kw)

즉, 특수화된 클래스가 kwds 딕셔너리에 추가하는 것은 제거해야 하고 처리해야 하며, kw(및 args)의 나머지 내용은 BaseHeader init 메서드로 전달됩니다.

class email.headerregistry.UnstructuredHeader

“구조화되지 않은” 헤더는 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]의 기본 헤더 유형입니다. 지정된 문법이 없는 헤더는 구조화되지 않은 것으로 취급됩니다. 구조화되지 않은 헤더의 전형적인 예는 Subject 헤더입니다.

RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]에서, 구조화되지 않은 헤더는 ASCII 문자 집합에서 임의의 텍스트를 나열합니다. 그러나 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html]은 비 ASCII 텍스트를 헤더 값 내에서 ASCII 문자로 인코딩하기 위한 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 호환 메커니즘을 가지고 있습니다. 인코딩된 단어를 포함하는 value가 생성자에 전달되면, UnstructuredHeader 구문 분석기는 구조화되지 않은 텍스트의 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 규칙에 따라 인코딩된 단어를 유니코드로 변환합니다. 구문 분석기는 휴리스틱을 사용하여 특정 비 호환 인코딩된 단어를 디코딩하려고 시도합니다. 인코딩된 단어나 인코딩되지 않는 텍스트 내의 유효하지 않은 문자와 같은 문제에 대한 결함뿐만 아니라 이럴 때 결함을 등록합니다.

이 헤더 유형은 추가 어트리뷰트를 제공하지 않습니다.

class email.headerregistry.DateHeader

RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]는 전자 우편 헤더 내의 날짜에 대해 매우 구체적인 형식을 지정합니다. DateHeader 구문 분석기는 이 날짜 형식을 인식할 뿐만 아니라, “야생”에서 발견되는 다양한 변종 형식을 인식합니다.

이 헤더 유형은 다음과 같은 추가 어트리뷰트를 제공합니다:

datetime

If the header value can be recognized as a valid date of one form or another, this attribute will contain a datetime instance representing that date. If the timezone of the input date is specified as -0000 (indicating it is in UTC but contains no information about the source timezone), then datetime will be a naive datetime. If a specific timezone offset is found (including +0000), then datetime will contain an aware datetime that uses datetime.timezone to record the timezone offset.

헤더의 decoded 값은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 규칙에 따라 datetime을 포매팅해서 결정됩니다; 즉, 다음과 같이 설정됩니다:

email.utils.format_datetime(self.datetime)

DateHeader를 만들 때, value는 datetime 인스턴스일 수 있습니다. 이것은, 예를 들어, 다음 코드가 유효하고 기대하는 것을 수행함을 뜻합니다:

msg['Date'] = datetime(2011, 7, 15, 21)

이것은 나이브 datetime이므로 UTC 타임스탬프로 해석되며 결괏값의 시간대는 -0000입니다. utils 모듈의 localtime() 함수를 사용하는 것이 훨씬 더 유용합니다:

msg['Date'] = utils.localtime()

이 예에서는 현재 시간대 오프셋을 사용하여 날짜 헤더를 현재 시간과 날짜로 설정합니다.

class email.headerregistry.AddressHeader

주소 헤더는 가장 복잡한 구조화된 헤더 유형 중 하나입니다. AddressHeader 클래스는 모든 주소 헤더에 대한 범용 인터페이스를 제공합니다.

이 헤더 유형은 다음과 같은 추가 어트리뷰트를 제공합니다:

groups

헤더 값에서 찾은 주소와 그룹을 인코딩하는 Group 객체의 튜플. 그룹 일부가 아닌 주소는 이 목록에서 display_name이 None인 단일 주소 Groups로 표현됩니다.

addresses

헤더 값의 모든 개별 주소를 인코딩하는 Address 객체의 튜플. 헤더 값이 그룹을 포함하면, 그룹의 개별 주소가 값에서 그룹이 발생하는 지점에서 목록에 포함됩니다 (즉, 주소 목록은 1차원 목록으로 “평평하게” 만들어집니다).

The decoded value of the header will have all encoded words decoded to unicode. idna encoded domain names are also decoded to unicode. The decoded value is set by joining the str value of the elements of the groups attribute with ', '.

Address와 Group 객체의 목록을 임의 조합한 목록을 주소 헤더의 값을 설정하는 데 사용할 수 있습니다. display_name이 None인 Group 객체는 단일 주소로 해석되므로, 소스 헤더의 groups 어트리뷰트에서 얻은 목록을 사용하여 주소 목록을 그룹과 함께 그대로 복사할 수 있습니다.

class email.headerregistry.SingleAddressHeader

하나의 추가 어트리뷰트를 추가하는 AddressHeader의 서브 클래스:

address

헤더 값으로 인코딩된 단일 주소. 헤더 값에 실제로 둘 이상의 주소가 포함될 때 (기본 policy에서 RFC 위반입니다), 이 어트리뷰트에 액세스하면 ValueError가 발생합니다.

위의 많은 클래스에는 Unique 변형도 있습니다 (예를 들어, UniqueUnstructuredHeader). 유일한 차이점은 Unique 변형에서 max_count가 1로 설정되어 있다는 것입니다.

class email.headerregistry.MIMEVersionHeader

MIME-Version 헤더에는 실제로 하나의 유효한 값만 있으며, 이는 1.0입니다. 미래에 안전하기 위해, 이 헤더 클래스는 다른 유효한 버전 번호를 지원합니다. 버전 번호가 RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]에 따라 유효한 값을 가지면, 헤더 객체는 다음 어트리뷰트에 None이 아닌 값을 갖습니다:

version

공백 및/또는 주석이 제거된 문자열 버전 번호.

major

정수 주 버전 번호

minor

정수 부 버전 번호

class email.headerregistry.ParameterizedMIMEHeader

MIME 헤더는 모두 접두사 ‘Content-‘로 시작합니다. 각 특정 헤더에는 해당 헤더의 클래스에 설명된 특정 값이 있습니다. 일부는 공통 형식을 가진 보조 파라미터 목록을 취할 수도 있습니다. 이 클래스는 파라미터를 취하는 모든 MIME 헤더의 베이스로 사용됩니다.

params

파라미터 이름을 파라미터값으로 매핑하는 딕셔너리.

class email.headerregistry.ContentTypeHeader

Content-Type 헤더를 처리하는 ParameterizedMIMEHeader 클래스.

content_type

maintype/subtype 형식의 콘텐츠 유형 문자열.

maintype

subtype

class email.headerregistry.ContentDispositionHeader

Content-Disposition 헤더를 처리하는 ParameterizedMIMEHeader 클래스.

content_disposition

inline과 attachment가 일반적으로 사용되는 유일하게 유효한 값입니다.

class email.headerregistry.ContentTransferEncoding

Content-Transfer-Encoding 헤더를 처리합니다.

cte

유효한 값은 7bit, 8bit, base64 및 quoted-printable입니다. 자세한 정보는 RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]를 참조하십시오.

class email.headerregistry.HeaderRegistry(base_class=BaseHeader, default_class=UnstructuredHeader, use_default_map=True)

This is the factory used by EmailPolicy by default. HeaderRegistry builds the class used to create a header instance dynamically, using base_class and a specialized class retrieved from a registry that it holds. When a given header name does not appear in the registry, the class specified by default_class is used as the specialized class. When use_default_map is True (the default), the standard mapping of header names to classes is copied in to the registry during initialization. base_class is always the last class in the generated class’s __bases__ list.

기본 매핑은 다음과 같습니다:

subject:

UniqueUnstructuredHeader

date:

UniqueDateHeader

resent-date:

DateHeader

orig-date:

UniqueDateHeader

sender:

UniqueSingleAddressHeader

resent-sender:

SingleAddressHeader

to:

UniqueAddressHeader

resent-to:

AddressHeader

cc:

UniqueAddressHeader

resent-cc:

AddressHeader

bcc:

UniqueAddressHeader

resent-bcc:

AddressHeader

from:

UniqueAddressHeader

resent-from:

AddressHeader

reply-to:

UniqueAddressHeader

mime-version:

MIMEVersionHeader

content-type:

ContentTypeHeader

content-disposition:

ContentDispositionHeader

content-transfer-encoding:

ContentTransferEncodingHeader

message-id:

MessageIDHeader

HeaderRegistry에는 다음과 같은 메서드가 있습니다:

map_to_type(self, name, cls)

name은 매핑할 헤더의 이름입니다. 등록소에서 소문자로 변환됩니다. cls는 name과 일치하는 헤더를 인스턴스 화하는 데 사용되는 클래스를 만들기 위해 base_class와 함께 사용되는 특수 클래스입니다.

__getitem__(name)

name 헤더 생성을 처리할 클래스를 구성하고 반환합니다.

__call__(name, value)

등록소에서 name과 연관된 특수화된 헤더를 꺼내고 (등록소에 name이 없으면 default_class를 사용해서), base_class와 결합하여 클래스를 생성하고, 생성된 클래스의 생성자를 같은 인자 목록을 전달해서 호출한 후, 마지막으로 이렇게 만들어진 클래스 인스턴스를 반환합니다.

다음 클래스는 구조화된 헤더에서 구문 분석된 데이터를 나타내는 데 사용되는 클래스이며 일반적으로 응용 프로그램에서 특정 헤더에 지정할 구조화된 값을 대입하는 데 사용할 수 있습니다.

class email.headerregistry.Address(display_name='', username='', domain='', addr_spec=None)

전자 우편 주소를 나타내는 데 사용되는 클래스. 주소의 일반적인 형식은 다음과 같습니다:

[display_name] <username@domain>

또는:

username@domain

여기서 각 부분은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]에 명시된 특정 문법 규칙을 준수해야 합니다.

편의상 username과 domain 대신 addr_spec을 지정할 수 있으며, 이 경우 addr_spec에서 username과 domain이 구문 분석됩니다. addr_spec은 올바르게 RFC 인용된 문자열(quoted string)이어야 합니다; 그렇지 않으면 Address는 에러를 발생시킵니다. 유니코드 문자는 허용되며 직렬화될 때 적절하게 인코딩됩니다. 그러나, RFC에 따라, 주소의 사용자 이름 부분에는 유니코드가 허용되지 않습니다.

display_name

모든 인용(quoting)이 제거된 주소의 표시 이름 부분 (있다면). 주소에 표시 이름이 없으면, 이 어트리뷰트는 빈 문자열입니다.

username

모든 인용(quoting)이 제거된 주소의 username 부분.

domain

주소의 domain 부분.

addr_spec

주소의 username@domain 부분, 단순 주소(위의 두 번째 형식)로 사용하기 위해 올바르게 인용(quoted)됩니다. 이 어트리뷰트는 불변입니다.

__str__()

객체의 str 값은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 규칙에 따라 인용된(quoted) 주소이지만, ASCII가 아닌 문자의 콘텐츠 전송 인코딩(Content Transfer Encoding)은 없습니다.

SMTP(RFC 5321 [https://datatracker.ietf.org/doc/html/rfc5321.html])를 지원하기 위해, Address는 한가지 특별한 경우를 처리합니다: username과 domain이 모두 빈 문자열(또는 None)이면, Address의 문자열 값은 <>입니다.

class email.headerregistry.Group(display_name=None, addresses=None)

주소 그룹을 표현하는 데 사용되는 클래스. 주소 그룹의 일반적인 형식은 다음과 같습니다:

display_name: [address-list];

그룹과 단일 주소의 혼합으로 구성된 주소 목록 처리의 편의를 위해, display_name을 None으로 설정하고 단일 주소 목록을 addresses로 제공하여, Group을 그룹의 일부가 아닌 단일 주소를 나타내는 데 사용할 수도 있습니다.

display_name

그룹의 display_name. None이고 addresses에 정확히 하나의 Address가 있으면, Group은 그룹에 속하지 않은 단일 주소를 나타냅니다.

addresses

그룹에 있는 주소를 나타내는 Address 객체의 비어있을 수 있는 튜플.

__str__()

Group의 str 값은 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html]에 따라 포맷되지만, ASCII가 아닌 문자의 콘텐츠 전송 인코딩(Content Transfer Encoding)은 없습니다. display_name이 None이고 addresses 목록에 단일 Address가 있으면 str 값은 해당 단일 Address의 str과 같습니다.

각주

[1]

원래 3.3에서 잠정적 모듈로 추가되었습니다.

email.contentmanager: Managing MIME Content

소스 코드: Lib/email/contentmanager.py [https://github.com/python/cpython/tree/main/Lib/email/contentmanager.py]

Added in version 3.6: [1]

class email.contentmanager.ContentManager

콘텐츠 관리자를 위한 베이스 클래스. get_content와 set_content 디스패치 메서드뿐만 아니라 MIME 콘텐츠와 다른 표현 간의 변환기를 등록하는 표준 등록소 메커니즘을 제공합니다.

get_content(msg, *args, **kw)

msg의 mimetype을 기반으로 처리기 함수를 찾고 (다음 단락을 참조하십시오), 모든 인자를 전달하여 그것을 호출하고, 이 호출의 결과를 반환합니다. 처리기가 msg에서 페이 로드를 추출하고 추출된 데이터에 대한 정보를 인코딩하는 객체를 반환할 것으로 기대합니다.

처리기를 찾으려면, 등록소에서 다음 키를 찾는데, 처음 발견되는 것에서 멈춥니다:

전체 MIME 유형을 나타내는 문자열 (maintype/subtype)

maintype을 나타내는 문자열

빈 문자열

이러한 키 중 아무것도 이러한 처리기를 생성하지 않으면, 전체 MIME 유형에 대해 KeyError를 발생시킵니다.

set_content(msg, obj, *args, **kw)

maintype이 multipart이면, TypeError를 발생시킵니다; 그렇지 않으면 obj의 형을 기반으로 처리기 함수를 찾고 (다음 단락을 참조하십시오), msg에서 clear_content()를 호출한 다음, 모든 인자를 전달해서 처리기 함수를 호출합니다. 처리기가 obj를 msg로 변환하고 저장할 것으로 기대하는데, 저장된 데이터를 해석하는 데 필요한 정보를 인코딩하기 위해 다양한 MIME 헤더를 추가하는 등 msg에 다른 변경을 가할 수 있습니다.

처리기를 찾으려면, obj의 형을 얻고 (typ = type(obj)), 등록소에서 다음 키를 찾는데 처음 발견되는 것에서 멈춥니다:

형 자체 (typ)

형의 완전히 정규화된 이름 (typ.__module__ + '.' + typ.__qualname__).

the type’s qualname (typ.__qualname__)

the type’s name (typ.__name__).

If none of the above match, repeat all of the checks above for each of the types in the MRO (typ.__mro__). Finally, if no other key yields a handler, check for a handler for the key None. If there is no handler for None, raise a KeyError for the fully qualified name of the type.

MIME-Version 헤더가 없으면 추가합니다 (MIMEPart를 참조하십시오).

add_get_handler(key, handler)

함수 handler를 key의 처리기로 기록합니다. 가능한 key 값은 get_content()를 참조하십시오.

add_set_handler(typekey, handler)

typekey와 일치하는 형의 객체가 set_content()에 전달될 때 호출할 함수로 handler를 기록합니다. 가능한 typekey 값은 set_content()를 참조하십시오.

콘텐츠 관리자 인스턴스

현재 email 패키지는 하나의 구상 콘텐츠 관리자 raw_data_manager만 제공하지만, 향후에는 더 추가될 수 있습니다. raw_data_manager는 EmailPolicy와 그 파생물에 의해 제공되는 content_manager입니다.

email.contentmanager.raw_data_manager

이 콘텐츠 관리자는 Message 자체에서 제공하는 것 외에는 최소 인터페이스 만 제공합니다: 텍스트, 날 바이트열 및 Message 객체만 다룹니다. 그런데도 기본 API와 비교할 때 상당한 이점을 제공합니다: 텍스트 파트에 대한 get_content는 응용 프로그램이 수동으로 디코딩할 필요 없이 유니코드 문자열을 반환하고, set_content는 파트에 추가된 헤더를 제어하고 콘텐츠 전송 인코딩을 제어하기 위한 다양한 옵션을 제공하고, 다양한 add_ 메서드를 사용할 수 있도록 해서, 멀티 파트 메시지 작성을 단순화합니다.

email.contentmanager.get_content(msg, errors='replace')

파트의 페이 로드를 문자열(text 파트의 경우), EmailMessage 객체 (message/rfc822 파트의 경우) 또는 bytes 객체 (다른 모든 비 멀티 파트 유형의 경우)로 반환합니다. multipart에서 호출되면 KeyError를 발생시킵니다. 파트가 text 파트이고 errors가 지정되면, 페이 로드를 유니코드로 디코딩할 때 에러 처리기로 사용합니다. 기본 에러 처리기는 replace입니다.

email.contentmanager.set_content(msg, <'str'>, subtype="plain", charset='utf-8', cte=None, disposition=None, filename=None, cid=None, params=None, headers=None)

email.contentmanager.set_content(msg, <'bytes'>, maintype, subtype, cte="base64", disposition=None, filename=None, cid=None, params=None, headers=None)

email.contentmanager.set_content(msg, <'EmailMessage'>, cte=None, disposition=None, filename=None, cid=None, params=None, headers=None)

msg에 헤더와 페이 로드를 추가합니다:

maintype/subtype 값으로 Content-Type 헤더를 추가합니다.

str의 경우, MIME maintype을 text로 설정하고, 서브 유형은 지정되었으면 subtype으로 설정하고, 지정되지 않았으면 plain으로 설정합니다.

bytes의 경우, 지정된 maintype과 subtype을 사용하거나, 지정되지 않았으면 TypeError를 발생시킵니다.

EmailMessage 객체의 경우, 메인 유형을 message로 설정하고, 서브 유형은 지정되었으면 subtype으로 설정하고, 지정되지 않았으면 rfc822로 설정합니다. subtype이 partial이면 에러를 발생시킵니다 (bytes 객체를 사용하여 message/partial 파트를 구성해야 합니다).

charset이 제공되면 (str에만 유효합니다), 지정된 문자 집합을 사용하여 문자열을 바이트열로 인코딩합니다. 기본값은 utf-8입니다. 지정된 charset이 표준 MIME 문자 집합 이름의 알려진 별칭이면, 표준 문자 집합을 대신 사용합니다.

cte가 설정되면, 지정된 콘텐츠 전송 인코딩을 사용하여 페이 로드를 인코딩하고, Content-Transfer-Encoding 헤더를 해당 값으로 설정합니다. cte의 가능한 값은 quoted-printable, base64, 7bit, 8bit 및 binary입니다. 지정된 인코딩으로 입력을 인코딩할 수 없으면 (예를 들어, 비 ASCII 값을 포함하는 입력에 대해 cte를 7bit로 지정합니다), ValueError를 발생시킵니다.

str 객체의 경우, cte가 설정되지 않으면 휴리스틱을 사용하여 가장 간결한 인코딩을 결정합니다.

EmailMessage의 경우, RFC 2046 [https://datatracker.ietf.org/doc/html/rfc2046.html]에 따라, subtype rfc822에 대해 quoted-printable이나 base64의 cte가 요청되거나, subtype external-body에 대해 7bit 이외의 cte에 대해 에러를 발생시킵니다. message/rfc822의 경우, cte가 지정되지 않으면 8bit를 사용합니다. subtype의 다른 모든 값에는 7bit를 사용합니다.

참고

binary의 cte는 실제로 아직 제대로 작동하지 않습니다. set_content에 의해 수정된 EmailMessage 객체는 올바르지만, BytesGenerator는 이것을 올바르게 직렬화하지 않습니다.

disposition이 설정되면, 이를 Content-Disposition 헤더의 값으로 사용합니다. 지정되지 않고 filename이 지정되면, 값이 attachment인 헤더를 추가합니다. disposition이 지정되지 않고 filename도 지정되지 않으면, 헤더를 추가하지 않습니다. disposition에 유효한 값은 attachment와 inline뿐 입니다.

filename이 지정되면, 이를 Content-Disposition 헤더의 filename 파라미터의 값으로 사용합니다.

cid가 지정되면, cid를 값으로 사용하여 Content-ID 헤더를 추가합니다.

params가 지정되면, 그것의 items 메서드를 이터레이트하고 결과 (key, value) 쌍을 사용하여 Content-Type 헤더에 추가 파라미터를 설정합니다.

headers가 지정되고 headername: headervalue 형식의 문자열 리스트나 header 객체 (name 어트리뷰트를 가진 것으로 문자열과 구별됩니다) 리스트면, 헤더를 msg에 추가합니다.

각주

[1]

원래 3.4에서 잠정적 모듈로 추가되었습니다.

email: 예제

다음은 email 패키지를 사용하여 간단한 전자 우편 메시지뿐만 아니라 더 복잡한 MIME 메시지를 읽고 쓰고 보내는 방법에 대한 몇 가지 예입니다.

먼저 간단한 텍스트 메시지를 만들고 보내는 방법을 살펴보겠습니다 (텍스트 내용과 주소에 유니코드 문자가 포함될 수 있습니다):

# Import smtplib for the actual sending function
import smtplib

# Import the email modules we'll need
from email.message import EmailMessage

# Open the plain text file whose name is in textfile for reading.
with open(textfile) as fp:
    # Create a text/plain message
    msg = EmailMessage()
    msg.set_content(fp.read())

# me == the sender's email address
# you == the recipient's email address
msg['Subject'] = f'The contents of {textfile}'
msg['From'] = me
msg['To'] = you

# Send the message via our own SMTP server.
s = smtplib.SMTP('localhost')
s.send_message(msg)
s.quit()

parser 모듈의 클래스를 사용하여 RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] 헤더를 쉽게 구문 분석할 수 있습니다:

# Import the email modules we'll need
#from email.parser import BytesParser
from email.parser import Parser
from email.policy import default

# If the e-mail headers are in a file, uncomment these two lines:
# with open(messagefile, 'rb') as fp:
#     headers = BytesParser(policy=default).parse(fp)

#  Or for parsing headers in a string (this is an uncommon operation), use:
headers = Parser(policy=default).parsestr(
        'From: Foo Bar <user@example.com>\n'
        'To: <someone_else@example.com>\n'
        'Subject: Test message\n'
        '\n'
        'Body would go here\n')

#  Now the header items can be accessed as a dictionary:
print('To: {}'.format(headers['to']))
print('From: {}'.format(headers['from']))
print('Subject: {}'.format(headers['subject']))

# You can also access the parts of the addresses:
print('Recipient username: {}'.format(headers['to'].addresses[0].username))
print('Sender name: {}'.format(headers['from'].addresses[0].display_name))

다음은 디렉터리에 있을 수 있는 가족사진을 포함하는 MIME 메시지를 보내는 방법의 예입니다:

# Import smtplib for the actual sending function.
import smtplib

# Here are the email package modules we'll need.
from email.message import EmailMessage

# Create the container email message.
msg = EmailMessage()
msg['Subject'] = 'Our family reunion'
# me == the sender's email address
# family = the list of all recipients' email addresses
msg['From'] = me
msg['To'] = ', '.join(family)
msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'

# Open the files in binary mode.  You can also omit the subtype
# if you want MIMEImage to guess it.
for file in pngfiles:
    with open(file, 'rb') as fp:
        img_data = fp.read()
    msg.add_attachment(img_data, maintype='image',
                                 subtype='png')

# Send the email via our own SMTP server.
with smtplib.SMTP('localhost') as s:
    s.send_message(msg)

다음은 디렉터리의 전체 내용을 전자 우편 메시지로 보내는 방법의 예입니다: [1]

#!/usr/bin/env python3

"""Send the contents of a directory as a MIME message."""

import os
import smtplib
# For guessing MIME type based on file name extension
import mimetypes

from argparse import ArgumentParser

from email.message import EmailMessage
from email.policy import SMTP

def main():
    parser = ArgumentParser(description="""\
Send the contents of a directory as a MIME message.
Unless the -o option is given, the email is sent by forwarding to your local
SMTP server, which then does the normal delivery process.  Your local machine
must be running an SMTP server.
""")
    parser.add_argument('-d', '--directory',
                        help="""Mail the contents of the specified directory,
                        otherwise use the current directory.  Only the regular
                        files in the directory are sent, and we don't recurse to
                        subdirectories.""")
    parser.add_argument('-o', '--output',
                        metavar='FILE',
                        help="""Print the composed message to FILE instead of
                        sending the message to the SMTP server.""")
    parser.add_argument('-s', '--sender', required=True,
                        help='The value of the From: header (required)')
    parser.add_argument('-r', '--recipient', required=True,
                        action='append', metavar='RECIPIENT',
                        default=[], dest='recipients',
                        help='A To: header value (at least one required)')
    args = parser.parse_args()
    directory = args.directory
    if not directory:
        directory = '.'
    # Create the message
    msg = EmailMessage()
    msg['Subject'] = f'Contents of directory {os.path.abspath(directory)}'
    msg['To'] = ', '.join(args.recipients)
    msg['From'] = args.sender
    msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'

    for filename in os.listdir(directory):
        path = os.path.join(directory, filename)
        if not os.path.isfile(path):
            continue
        # Guess the content type based on the file's extension.  Encoding
        # will be ignored, although we should check for simple things like
        # gzip'd or compressed files.
        ctype, encoding = mimetypes.guess_file_type(path)
        if ctype is None or encoding is not None:
            # No guess could be made, or the file is encoded (compressed), so
            # use a generic bag-of-bits type.
            ctype = 'application/octet-stream'
        maintype, subtype = ctype.split('/', 1)
        with open(path, 'rb') as fp:
            msg.add_attachment(fp.read(),
                               maintype=maintype,
                               subtype=subtype,
                               filename=filename)
    # Now send or store the message
    if args.output:
        with open(args.output, 'wb') as fp:
            fp.write(msg.as_bytes(policy=SMTP))
    else:
        with smtplib.SMTP('localhost') as s:
            s.send_message(msg)

if __name__ == '__main__':
    main()

다음은 위와 같은 MIME 메시지를 디렉터리로 푸는 방법의 예입니다:

#!/usr/bin/env python3

"""Unpack a MIME message into a directory of files."""

import os
import email
import mimetypes

from email.policy import default

from argparse import ArgumentParser

def main():
    parser = ArgumentParser(description="""\
Unpack a MIME message into a directory of files.
""")
    parser.add_argument('-d', '--directory', required=True,
                        help="""Unpack the MIME message into the named
                        directory, which will be created if it doesn't already
                        exist.""")
    parser.add_argument('msgfile')
    args = parser.parse_args()

    with open(args.msgfile, 'rb') as fp:
        msg = email.message_from_binary_file(fp, policy=default)

    try:
        os.mkdir(args.directory)
    except FileExistsError:
        pass

    counter = 1
    for part in msg.walk():
        # multipart/* are just containers
        if part.get_content_maintype() == 'multipart':
            continue
        # Applications should really sanitize the given filename so that an
        # email message can't be used to overwrite important files
        filename = part.get_filename()
        if not filename:
            ext = mimetypes.guess_extension(part.get_content_type())
            if not ext:
                # Use a generic bag-of-bits extension
                ext = '.bin'
            filename = f'part-{counter:03d}{ext}'
        counter += 1
        with open(os.path.join(args.directory, filename), 'wb') as fp:
            fp.write(part.get_payload(decode=True))

if __name__ == '__main__':
    main()

다음은 대체 일반 텍스트 버전으로 HTML 메시지를 만드는 방법의 예입니다. 좀 더 흥미롭게 하기 위해, html 부분에 관련 이미지를 포함하고, 보낼 뿐만 아니라, 보낼 것의 사본을 디스크에 저장합니다.

#!/usr/bin/env python3

import smtplib

from email.message import EmailMessage
from email.headerregistry import Address
from email.utils import make_msgid

# Create the base text message.
msg = EmailMessage()
msg['Subject'] = "Pourquoi pas des asperges pour ce midi ?"
msg['From'] = Address("Pepé Le Pew", "pepe", "example.com")
msg['To'] = (Address("Penelope Pussycat", "penelope", "example.com"),
             Address("Fabrette Pussycat", "fabrette", "example.com"))
msg.set_content("""\
Salut!

Cette recette [1] sera sûrement un très bon repas.

[1] http://www.yummly.com/recipe/Roasted-Asparagus-Epicurious-203718

--Pepé
""")

# Add the html version.  This converts the message into a multipart/alternative
# container, with the original text message as the first part and the new html
# message as the second part.
asparagus_cid = make_msgid()
msg.add_alternative("""\
<html>
  <head></head>
  <body>
    <p>Salut!</p>
    <p>Cette
        <a href="http://www.yummly.com/recipe/Roasted-Asparagus-Epicurious-203718">
            recette
        </a> sera sûrement un très bon repas.
    </p>
    <img src="cid:{asparagus_cid}" />
  </body>
</html>
""".format(asparagus_cid=asparagus_cid[1:-1]), subtype='html')
# note that we needed to peel the <> off the msgid for use in the html.

# Now add the related image to the html part.
with open("roasted-asparagus.jpg", 'rb') as img:
    msg.get_payload()[1].add_related(img.read(), 'image', 'jpeg',
                                     cid=asparagus_cid)

# Make a local copy of what we are going to send.
with open('outgoing.msg', 'wb') as f:
    f.write(bytes(msg))

# Send the message via local SMTP server.
with smtplib.SMTP('localhost') as s:
    s.send_message(msg)

마지막 예에서 메시지를 보냈다면, 다음은 그것을 처리하는 한 가지 방법입니다:

import os
import sys
import tempfile
import mimetypes
import webbrowser

# Import the email modules we'll need
from email import policy
from email.parser import BytesParser

def magic_html_parser(html_text, partfiles):
    """Return safety-sanitized html linked to partfiles.

    Rewrite the href="cid:...." attributes to point to the filenames in partfiles.
    Though not trivial, this should be possible using html.parser.
    """
    raise NotImplementedError("Add the magic needed")

# In a real program you'd get the filename from the arguments.
with open('outgoing.msg', 'rb') as fp:
    msg = BytesParser(policy=policy.default).parse(fp)

# Now the header items can be accessed as a dictionary, and any non-ASCII will
# be converted to unicode:
print('To:', msg['to'])
print('From:', msg['from'])
print('Subject:', msg['subject'])

# If we want to print a preview of the message content, we can extract whatever
# the least formatted payload is and print the first three lines.  Of course,
# if the message has no plain text part printing the first three lines of html
# is probably useless, but this is just a conceptual example.
simplest = msg.get_body(preferencelist=('plain', 'html'))
print()
print(''.join(simplest.get_content().splitlines(keepends=True)[:3]))

ans = input("View full message?")
if ans.lower()[0] == 'n':
    sys.exit()

# We can extract the richest alternative in order to display it:
richest = msg.get_body()
partfiles = {}
if richest['content-type'].maintype == 'text':
    if richest['content-type'].subtype == 'plain':
        for line in richest.get_content().splitlines():
            print(line)
        sys.exit()
    elif richest['content-type'].subtype == 'html':
        body = richest
    else:
        print("Don't know how to display {}".format(richest.get_content_type()))
        sys.exit()
elif richest['content-type'].content_type == 'multipart/related':
    body = richest.get_body(preferencelist=('html'))
    for part in richest.iter_attachments():
        fn = part.get_filename()
        if fn:
            extension = os.path.splitext(part.get_filename())[1]
        else:
            extension = mimetypes.guess_extension(part.get_content_type())
        with tempfile.NamedTemporaryFile(suffix=extension, delete=False) as f:
            f.write(part.get_content())
            # again strip the <> to go from email form of cid to html form.
            partfiles[part['content-id'][1:-1]] = f.name
else:
    print("Don't know how to display {}".format(richest.get_content_type()))
    sys.exit()
with tempfile.NamedTemporaryFile(mode='w', delete=False) as f:
    f.write(magic_html_parser(body.get_content(), partfiles))
webbrowser.open(f.name)
os.remove(f.name)
for fn in partfiles.values():
    os.remove(fn)

# Of course, there are lots of email messages that could break this simple
# minded program, but it will handle the most common ones.

프롬프트까지, 위의 출력은 다음과 같습니다:

To: Penelope Pussycat <penelope@example.com>, Fabrette Pussycat <fabrette@example.com>
From: Pepé Le Pew <pepe@example.com>
Subject: Pourquoi pas des asperges pour ce midi ?

Salut!

Cette recette [1] sera sûrement un très bon repas.

각주

[1]

영감과 예를 주신 Matthew Dixon Cowles에게 감사드립니다.

email.message.Message: compat32 API를 사용하여 이메일 메시지 표현하기

Message 클래스는 EmailMessage 클래스와 매우 유사지만, 이 클래스에 의해 추가된 메서드가 없고, 다른 특정 메서드의 기본 동작이 약간 다릅니다. 또한 EmailMessage 클래스에서 지원하지만, 레거시 코드를 다루지 않는 한 권장되지 않는 일부 메서드도 여기에서 설명합니다.

두 클래스의 철학과 구조는 그 외에는 같습니다.

이 문서는 기본 (Message의 경우) 정책 Compat32의 동작을 설명합니다. 다른 정책을 사용하려면, EmailMessage 클래스를 대신 사용해야 합니다.

An email message consists of headers and a payload. Headers must be RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] style names and values, where the field name and value are separated by a colon. The colon is not part of either the field name or the field value. The payload may be a simple text message, or a binary object, or a structured sequence of sub-messages each with their own set of headers and their own payload. The latter type of payload is indicated by the message having a MIME type such as multipart/* or message/rfc822.

Message 객체가 제공하는 개념 모델은 헤더의 순서 있는 딕셔너리이면서, 헤더의 특수 정보에 액세스하고, 페이 로드에 액세스하고, 메시지의 직렬화된 버전을 생성하고, 객체 트리를 재귀적으로 탐색하기 위한 추가 메서드가 제공되는 것입니다. 중복 헤더가 지원되지만, 특수한 메서드를 사용하여 액세스해야 함에 유의하십시오.

Message 의사 딕셔너리는 헤더 이름으로 인덱싱되며, ASCII 값이어야 합니다. 딕셔너리의 값은 ASCII 문자만 포함해야 하는 문자열입니다; 비 ASCII 입력에 대한 특수 처리가 있지만, 항상 올바른 결과를 생성하지는 않습니다. 헤더는 대소 문자를 유지하면서 저장되고 반환되지만, 필드 이름은 대소 문자를 구분하지 않고 일치합니다. Unix-From 헤더나 From_ 헤더라고도 하는 단일 봉투 헤더가 있을 수도 있습니다. 페이 로드(payload)는 단순 메시지 객체의 경우는 문자열이나 바이트열이고, MIME 컨테이너 문서(예를 들어 multipart/*와 message/rfc822)의 경우는 Message 객체의 리스트입니다.

Message 클래스의 메서드는 다음과 같습니다:

class email.message.Message(policy=compat32)

policy가 지정되면 (policy 클래스의 인스턴스여야 합니다) 메시지 표현을 갱신하고 직렬화하기 위해 지정된 규칙을 사용합니다. policy가 설정되지 않으면, compat32 정책을 사용하는데, 파이썬 3.2 버전의 email 패키지와의 과거 호환성을 유지합니다. 자세한 내용은 policy 설명서를 참조하십시오.

버전 3.3에서 변경: policy 키워드 인자가 추가되었습니다.

as_string(unixfrom=False, maxheaderlen=0, policy=None)

평활화된 전체 메시지를 문자열로 반환합니다. 선택적 unixfrom이 참이면, 봉투 헤더가 반환된 문자열에 포함됩니다. unixfrom의 기본값은 False입니다. 이전 버전과의 호환성을 위해, maxheaderlen의 기본값이 0이라서 다른 값을 원하면 명시적으로 재정의해야 합니다 (정책에서 max_line_length에 지정된 값은 이 메서드가 무시합니다). policy 인자는 메시지 인스턴스에서 얻은 기본 정책을 대체하는 데 사용될 수 있습니다. 지정된 policy가 Generator로 전달되므로, 메서드에서 생성된 일부 포매팅을 제어하는 데 사용할 수 있습니다.

문자열로의 변환을 완료하기 위해 기본값을 채워야 하면 메시지 평활화는 Message에 대한 변경을 유발할 수 있습니다 (예를 들어, MIME 경계가 생성되거나 수정될 수 있습니다).

Note that this method is provided as a convenience and may not always format the message the way you want. For example, by default it does not do the mangling of lines that begin with From that is required by the Unix mbox format. For more flexibility, instantiate a Generator instance and use its flatten() method directly. For example:

from io import StringIO
from email.generator import Generator
fp = StringIO()
g = Generator(fp, mangle_from_=True, maxheaderlen=60)
g.flatten(msg)
text = fp.getvalue()

메시지 객체가 RFC 표준에 따라 인코딩되지 않은 바이너리 데이터를 포함하면, 비 호환 데이터는 유니코드 “unknown character” 코드 포인트로 대체됩니다. (as_bytes()와 BytesGenerator도 참조하십시오.)

버전 3.4에서 변경: policy 키워드 인자가 추가되었습니다.

__str__()

Equivalent to as_string(). Allows str(msg) to produce a string containing the formatted message.

as_bytes(unixfrom=False, policy=None)

평활화된 전체 메시지를 바이트열 객체로 반환합니다. 선택적 unixfrom이 참이면, 봉투 헤더가 반환된 문자열에 포함됩니다. unixfrom의 기본값은 False입니다. policy 인자는 메시지 인스턴스에서 얻은 기본 정책을 대체하는 데 사용될 수 있습니다. 지정된 policy가 BytesGenerator로 전달되므로, 메서드에서 생성된 일부 포매팅을 제어하는 데 사용할 수 있습니다.

문자열로의 변환을 완료하기 위해 기본값을 채워야 하면 메시지 평활화는 Message에 대한 변경을 유발할 수 있습니다 (예를 들어, MIME 경계가 생성되거나 수정될 수 있습니다).

Note that this method is provided as a convenience and may not always format the message the way you want. For example, by default it does not do the mangling of lines that begin with From that is required by the Unix mbox format. For more flexibility, instantiate a BytesGenerator instance and use its flatten() method directly. For example:

from io import BytesIO
from email.generator import BytesGenerator
fp = BytesIO()
g = BytesGenerator(fp, mangle_from_=True, maxheaderlen=60)
g.flatten(msg)
text = fp.getvalue()

Added in version 3.4.

__bytes__()

Equivalent to as_bytes(). Allows bytes(msg) to produce a bytes object containing the formatted message.

Added in version 3.4.

is_multipart()

메시지의 페이 로드가 서브-Message 객체의 리스트이면 True를, 그렇지 않으면 False를 반환합니다. is_multipart()가 False를 반환할 때, 페이 로드는 문자열 객체(CTE로 인코딩된 바이너리 페이 로드일 수 있습니다)여야 합니다. (True를 반환하는 is_multipart()가 반드시 “msg.get_content_maintype() == ‘multipart’” 가 True를 반환한다는 것을 의미하지는 않습니다. 예를 들어, Message가 message/rfc822 유형일 때, is_multipart는 True를 반환합니다.

set_unixfrom(unixfrom)

메시지의 봉투 헤더를 (문자열이어야 하는) unixfrom으로 설정합니다.

get_unixfrom()

메시지의 봉투 헤더를 반환합니다. 봉투 헤더가 설정되지 않았으면 기본값은 None입니다.

attach(payload)

지정된 payload를 현재 페이 로드에 추가합니다. 호출 전에는 페이 로드가 None이나 Message 객체의 리스트여야 합니다. 호출 후에는 페이 로드가 항상 Message 객체의 리스트입니다. 페이 로드를 스칼라 객체(예를 들어 문자열)로 설정하려면, set_payload()를 대신 사용하십시오.

이것은 레거시 메서드입니다. EmailMessage 클래스에서 해당 기능은 set_content()와 관련 make와 add 메서드로 대체됩니다.

get_payload(i=None, decode=False)

현재 페이 로드를 반환합니다. is_multipart()가 True이면 Message 객체의 리스트이고, is_multipart()가 False이면 문자열입니다. 페이 로드가 리스트이고 리스트 객체를 변경하면, 메시지의 페이 로드를 제자리에서 수정하는 것입니다.

선택적 인자 i를 사용하면, get_payload()는 is_multipart()가 True일 때, 페이 로드의 i 번째 요소를 0부터 세어 반환합니다. i가 0보다 작거나 페이 로드의 항목 수보다 크거나 같으면 IndexError가 발생합니다. 페이 로드가 문자열이고 (즉 is_multipart()가 False) i가 제공되면, TypeError가 발생합니다.

선택적 decode는 Content-Transfer-Encoding 헤더에 따라 페이 로드를 디코딩해야 하는지를 나타내는 플래그입니다. True이고 메시지가 멀티 파트가 아닐 때, 이 헤더 값이 quoted-printable이나 base64이면 페이 로드가 디코딩됩니다. 다른 인코딩이 사용되거나 Content-Transfer-Encoding 헤더가 누락되면, 페이 로드는 그대로 (디코딩되지 않고) 반환됩니다. 모든 경우에 반환된 값은 바이너리 데이터입니다. 메시지가 멀티 파트이고 decode 플래그가 True이면, None이 반환됩니다. 페이 로드가 base64이고 완벽하게 구성되지 않았으면 (패딩 누락, base64 알파벳 이외의 문자), 메시지의 결함 프로퍼티에 적절한 결함이 추가됩니다 (각각 InvalidBase64PaddingDefect나 InvalidBase64CharactersDefect).

decode가 False(기본값)일 때 본문은 Content-Transfer-Encoding을 디코딩하지 않고 문자열로 반환됩니다. 그러나, Content-Transfer-Encoding이 8비트인 경우, replace 에러 처리기로, Content-Type 헤더에 지정된 charset을 사용하여 원래 바이트를 디코딩하려고 시도합니다. charset이 지정되지 않았거나 email 패키지가 charset을 인식하지 못하면, 본문은 기본 ASCII 문자 집합을 사용하여 디코딩됩니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서는 해당 기능이 get_content()와 iter_parts()로 대체되었습니다.

set_payload(payload, charset=None)

전체 메시지 객체의 페이 로드를 payload로 설정합니다. 페이 로드 불변량(invariants)을 보장하는 것은 고객의 책임입니다. 선택적 charset은 메시지의 기본 문자 집합을 설정합니다; 자세한 내용은 set_charset()을 참조하십시오.

이것은 레거시 메서드입니다. EmailMessage 클래스에서는 해당 기능이 set_content()로 대체되었습니다.

set_charset(charset)

페이 로드의 문자 집합을 charset으로 설정합니다. 이는 Charset 인스턴스 (email.charset을 참조하십시오), 문자 집합의 이름을 지정하는 문자열 또는 None일 수 있습니다. 문자열이면, Charset 인스턴스로 변환됩니다. charset이 None이면, charset 매개 변수가 Content-Type 헤더에서 제거됩니다 (그렇지 않으면 메시지가 수정되지 않습니다). 그 외의 경우는 TypeError를 생성합니다.

기존 MIME-Version 헤더가 없으면 추가됩니다. 기존 Content-Type 헤더가 없으면, text/plain 값으로 추가됩니다. Content-Type 헤더가 존재하는지와 관계없이, charset 매개 변수는 charset.output_charset으로 설정됩니다. charset.input_charset과 charset.output_charset이 다르면, 페이 로드가 output_charset으로 다시 인코딩됩니다. 기존 Content-Transfer-Encoding 헤더가 없으면, 필요하면 지정된 Charset을 사용하여 페이 로드가 전송 인코딩되고(transfer-encoded), 적절한 값을 가진 헤더가 추가됩니다. Content-Transfer-Encoding 헤더가 이미 존재하면, 페이 로드는 해당 Content-Transfer-Encoding을 사용하여 이미 올바르게 인코딩된 것으로 가정하며 수정하지 않습니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서 해당 기능은 email.emailmessage.EmailMessage.set_content() 메서드의 charset 매개 변수로 대체됩니다.

get_charset()

메시지 페이 로드와 연관된 Charset 인스턴스를 반환합니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서는 항상 None을 반환합니다.

다음 메서드는 메시지의 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 헤더에 액세스하기 위한 매핑과 유사한 인터페이스를 구현합니다. 이 메서드들과 일반적인 매핑 (즉, 딕셔너리) 인터페이스 사이에는 의미상 차이가 있습니다. 예를 들어, 딕셔너리에는 중복 키가 없지만, 여기에는 중복 메시지 헤더가 있을 수 있습니다. 또한, 딕셔너리에서는 keys()가 반환하는 키의 순서가 보장되지 않지만, Message 객체에서는 헤더가 항상 원래 메시지에 나타나거나 나중에 메시지에 추가된 순서대로 반환됩니다. 삭제한 후 다시 추가된 헤더는 항상 헤더 리스트의 끝에 추가됩니다.

이러한 의미상 차이는 의도적이며 최대한의 편의를 위해 편향되어 있습니다.

모든 경우에, 메시지에 존재하는 봉투 헤더는 매핑 인터페이스에 포함되지 않습니다.

In a model generated from bytes, any header values that (in contravention of the RFCs) contain non-ASCII bytes will, when retrieved through this interface, be represented as Header objects with a charset of unknown-8bit.

__len__()

중복을 포함하여, 총 헤더 수를 반환합니다.

__contains__(name)

메시지 객체에 name이라는 이름의 필드가 있으면 True를 반환합니다. 대소 문자를 구분하지 않고 일치하며 name은 후행 콜론을 포함하지 않아야 합니다. in 연산자에 사용됩니다, 예를 들어:

if 'message-id' in myMessage:
   print('Message-ID:', myMessage['message-id'])

__getitem__(name)

명명된 헤더 필드의 값을 반환합니다. name은 콜론 필드 구분자를 포함하지 않아야 합니다. 헤더가 없으면, None이 반환됩니다; KeyError는 절대 발생하지 않습니다.

이름이 지정된 필드가 메시지 헤더에 두 번 이상 나타나면, 해당 필드 값 중 정확히 어떤 필드 값이 반환되는지 정의되지 않습니다. 기존의 모든 명명된 헤더의 값을 가져오려면 get_all() 메서드를 사용하십시오.

__setitem__(name, val)

메시지에 필드 이름이 name이고 값이 val인 헤더를 추가합니다. 필드는 메시지의 기존 필드 끝에 추가됩니다.

이것이 같은 이름을 가진 기존 헤더를 덮어쓰거나 삭제하지 않음에 유의하십시오. 새 헤더가 메시지에 필드 이름이 name인 유일한 헤더가 되도록 하려면, 먼저 필드를 삭제하십시오. 예를 들어:

del msg['subject']
msg['subject'] = 'Python roolz!'

__delitem__(name)

메시지 헤더에서 이름이 name인 모든 필드를 삭제합니다. 명명된 필드가 헤더에 없어도 예외가 발생하지 않습니다.

keys()

메시지 헤더의 모든 필드 이름의 리스트를 반환합니다.

values()

메시지의 모든 필드 값의 리스트를 반환합니다.

items()

메시지의 모든 필드 헤더와 값을 포함하는 2-튜플의 리스트를 반환합니다.

get(name, failobj=None)

Return the value of the named header field. This is identical to __getitem__() except that optional failobj is returned if the named header is missing (defaults to None).

몇 가지 유용한 추가 메서드가 있습니다:

get_all(name, failobj=None)

name이라는 필드의 모든 값 리스트를 반환합니다. 메시지에 이런 이름의 헤더가 없으면, failobj가 반환됩니다 (기본값은 None입니다).

add_header(_name, _value, **_params)

확장된 헤더 설정. 이 메서드는 추가 헤더 매개 변수가 키워드 인자로 제공될 수 있다는 점을 제외하고는 __setitem__()과 유사합니다. _name은 추가할 헤더 필드이고 _value는 헤더의 기본(primary)값입니다.

키워드 인자 딕셔너리 _params의 각 항목에 대해, 키는 매개 변수 이름으로 사용되며, 밑줄은 대시로 변환됩니다 (대시는 파이썬 식별자로 유효하지 않기 때문입니다). 일반적으로, 값이 None이 아니면 매개 변수가 key="value"로 추가되며, None이면 키만 추가됩니다. 값에 ASCII가 아닌 문자가 포함되면, (CHARSET, LANGUAGE, VALUE) 형식으로 3-튜플로 지정할 수 있습니다. 여기서 CHARSET은 값을 인코딩하는 데 사용할 문자 집합의 이름을 지정하는 문자열이고, LANGUAGE는 일반적으로 None이나 빈 문자열(다른 가능성에 대해서는 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]을 참조하십시오)로 설정될 수 있고, VALUE는 비 ASCII 코드 포인트를 포함하는 문자열 값입니다. 3-튜플이 전달되지 않고 값에 ASCII가 아닌 문자가 포함되면, CHARSET으로 utf-8을 LANGUAGE로 None을 사용하여 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html] 형식으로 자동 인코딩됩니다.

예를 들면 다음과 같습니다:

msg.add_header('Content-Disposition', 'attachment', filename='bud.gif')

이것은 다음과 같은 헤더를 추가합니다

Content-Disposition: attachment; filename="bud.gif"

비 ASCII 문자의 예:

msg.add_header('Content-Disposition', 'attachment',
               filename=('iso-8859-1', '', 'Fußballer.ppt'))

이것은 다음을 생성합니다

Content-Disposition: attachment; filename*="iso-8859-1''Fu%DFballer.ppt"

replace_header(_name, _value)

헤더를 교체합니다. 헤더 순서와 필드 이름 대소 문자를 유지하면서, 메시지에서 _name과 일치하는 첫 번째로 발견된 헤더를 교체합니다. 일치하는 헤더가 없으면, KeyError가 발생합니다.

get_content_type()

메시지의 콘텐츠 유형을 반환합니다. 반환된 문자열은 maintype/subtype 형식의 소문자로 강제 변환됩니다. 메시지에 Content-Type 헤더가 없으면 get_default_type()에서 제공하는 기본 유형이 반환됩니다. RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]에 따르면, 메시지는 항상 기본 유형을 가지므로, get_content_type()은 항상 값을 반환합니다.

RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]는 메시지가 multipart/digest 컨테이너 안에 등장(이 경우 기본 유형은 message/rfc822가 됩니다)하지 않는 한 기본 유형을 text/plain으로 정의합니다. Content-Type 헤더에 유효하지 않은 유형 명세가 있으면, RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]는 기본 유형이 text/plain으로 지정합니다.

get_content_maintype()

메시지의 주 콘텐츠 유형을 반환합니다. 이것은 get_content_type()이 반환하는 문자열의 maintype 부분입니다.

get_content_subtype()

메시지의 부 콘텐츠 유형을 반환합니다. 이것은 get_content_type()이 반환하는 문자열의 subtype 부분입니다.

get_default_type()

기본 콘텐츠 유형을 반환합니다. multipart/digest 컨테이너의 서브 파트인 메시지를 제외하고, 대부분의 메시지는 기본 콘텐츠 유형이 text/plain입니다. 이러한 서브 파트는 기본 콘텐츠 유형이 message/rfc822입니다.

set_default_type(ctype)

기본 콘텐츠 유형을 설정합니다. ctype은 text/plain이나 message/rfc822여야 하지만 강제하지는 않습니다. 기본 콘텐츠 유형은 Content-Type 헤더에 저장되지 않습니다.

get_params(failobj=None, header='content-type', unquote=True)

메시지의 Content-Type 매개 변수를 리스트로 반환합니다. 반환된 리스트의 요소는 '=' 부호로 분할된 키/값 쌍의 2-튜플입니다. '='의 왼쪽은 키이고 오른쪽은 값입니다. 매개 변수에 '=' 부호가 없으면 값은 빈 문자열이고, 그렇지 않으면 값은 get_param()에 설명된대로이며 선택적 unquote가 True(기본값)이면 인용되지 않습니다.

선택적 failobj는 Content-Type 헤더가 없을 때 반환할 객체입니다. 선택적 header는 Content-Type 대신 검색할 헤더입니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서 해당 기능은 헤더 액세스 메서드가 반환한 개별 헤더 객체의 params 프로퍼티로 대체됩니다.

get_param(param, failobj=None, header='content-type', unquote=True)

Content-Type 헤더의 매개 변수 param의 값을 문자열로 반환합니다. 메시지에 Content-Type 헤더가 없거나 그러한 매개 변수가 없으면, failobj가 반환됩니다 (기본값은 None입니다).

선택적 header가 제공되면, Content-Type 대신 사용할 메시지 헤더를 지정합니다.

매개 변수 키는 항상 대소 문자를 구분하지 않고 비교됩니다. 반환 값은 문자열이거나, 매개 변수가 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]로 인코딩되었으면 3-튜플일 수 있습니다. 3-튜플일 때, 값의 요소는 (CHARSET, LANGUAGE, VALUE) 형식입니다. CHARSET과 LANGUAGE는 모두 None일 수 있으며, 이 경우 VALUE가 us-ascii 문자 집합으로 인코딩된 것으로 간주해야 함에 유의하십시오. 일반적으로 LANGUAGE를 무시할 수 있습니다.

응용 프로그램이 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]로 매개 변수가 인코딩되었는지를 신경 쓰지 않으면, email.utils.collapse_rfc2231_value()를 호출하면서 get_param()의 반환 값을 전달하여 매개 변숫값을 축소할 수 있습니다. 이것은 값이 튜플이면 적절하게 디코딩된 유니코드 문자열을 반환하고, 그렇지 않으면 원래 문자열을 인용 없이 반환합니다. 예를 들면:

rawparam = msg.get_param('foo')
param = email.utils.collapse_rfc2231_value(rawparam)

모든 경우에, unquote가 False로 설정되어 있지 않으면, 매개 변숫값(반환된 문자열이나 3-튜플의 VALUE 항목)은 항상 인용되지 않습니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서 해당 기능은 헤더 액세스 메서드가 반환한 개별 헤더 객체의 params 프로퍼티로 대체됩니다.

set_param(param, value, header='Content-Type', requote=True, charset=None, language='', replace=False)

Content-Type 헤더에서 매개 변수를 설정합니다. 매개 변수가 이미 헤더에 존재하면, 해당 값은 value로 대체됩니다. 이 메시지에 대해 Content-Type 헤더가 아직 정의되지 않았으면, text/plain으로 설정되고 RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]에 따라 새 매개 변숫값이 추가됩니다.

선택적 header는 Content-Type의 대체 헤더를 지정하며, 선택적 requote가 False(기본값은 True)가 아닌 한 모든 매개 변수가 필요에 따라 인용됩니다.

선택적 charset이 지정되면, 매개 변수는 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]에 따라 인코딩됩니다. 선택적 language는 RFC 2231 언어를 지정하며, 기본값은 빈 문자열입니다. charset과 language는 모두 문자열이어야 합니다.

replace가 False(기본값)이면 헤더가 헤더 리스트의 끝으로 이동합니다. replace가 True이면, 헤더는 제자리에서 갱신됩니다.

버전 3.4에서 변경: replace 키워드가 추가되었습니다.

del_param(param, header='content-type', requote=True)

Content-Type 헤더에서 지정된 매개 변수를 완전히 제거합니다. 매개 변수나 그 값 없이 헤더가 다시 작성됩니다. requote가 False(기본값은 True)가 아닌 한 모든 값이 필요에 따라 인용됩니다. 선택적 header는 Content-Type의 대체 헤더를 지정합니다.

set_type(type, header='Content-Type', requote=True)

Content-Type 헤더의 주 유형과 부 유형을 설정합니다. type은 maintype/subtype 형식의 문자열이어야 합니다, 그렇지 않으면 ValueError가 발생합니다.

이 메서드는 모든 매개 변수를 그대로 유지하면서 Content-Type 헤더를 대체합니다. requote가 False이면, 기존 헤더의 인용을 그대로 두고, 그렇지 않으면 매개 변수가 인용됩니다 (기본값).

header 인자에 대체 헤더를 지정할 수 있습니다. Content-Type 헤더가 설정될 때 MIME-Version 헤더도 추가됩니다.

이것은 레거시 메서드입니다. EmailMessage 클래스에서 해당 기능은 make_와 add_ 메서드로 대체됩니다.

get_filename(failobj=None)

메시지의 Content-Disposition 헤더의 filename 매개 변숫값을 반환합니다. 헤더에 filename 매개 변수가 없으면, 이 메서드는 Content-Type 헤더에서 name 매개 변수를 찾는 것으로 폴 백합니다. 둘 다 없거나, 헤더가 없으면, failobj가 반환됩니다. 반환된 문자열은 항상 email.utils.unquote()로 인용 해제됩니다.

get_boundary(failobj=None)

메시지의 Content-Type 헤더의 boundary 매개 변숫값이나, 헤더가 없거나 boundary 매개 변수가 없으면 failobj를 반환합니다. 반환된 문자열은 항상 email.utils.unquote()로 인용 해제됩니다.

set_boundary(boundary)

Content-Type 헤더의 boundary 매개 변수를 boundary로 설정합니다. 필요하면 set_boundary()는 항상 boundary를 인용합니다. 메시지 객체에 Content-Type 헤더가 없으면 HeaderParseError 가 발생합니다.

set_boundary()는 헤더 리스트에서 Content-Type 헤더의 순서를 유지하므로, 이 메서드를 사용하는 것은 이전 Content-Type 헤더를 삭제하고 add_header()를 통해 새 경계를 가진 새 헤더를 추가하는 것과 미묘하게 다름에 유의하십시오. 그러나 원래 Content-Type 헤더에 있을 수 있는 이어지는 줄(continuation lines)을 유지하지 않습니다.

get_content_charset(failobj=None)

Content-Type 헤더의 charset 매개 변수를 소문자로 강제 변환하여 반환합니다. Content-Type 헤더가 없거나, 해당 헤더에 charset 매개 변수가 없으면 failobj가 반환됩니다.

이 메서드는 메시지 본문의 기본 인코딩에 대한 Charset 인스턴스를 반환하는 get_charset()과 다름에 유의하십시오.

get_charsets(failobj=None)

메시지 내의 문자 집합 이름을 포함하는 리스트를 반환합니다. 메시지가 multipart이면, 리스트에 페이 로드의 각 서브 파트마다 하나의 요소가 포함되며, 그렇지 않으면 길이 1인 리스트가 됩니다.

리스트의 각 항목은 표현된 서브 파트에 대한 Content-Type 헤더의 charset 매개 변숫값인 문자열입니다. 그러나, 서브 파트에 Content-Type 헤더가 없거나, charset 매개 변수가 없거나, text 주 MIME 유형이 아니면, 반환된 목록의 해당 항목은 failobj가 됩니다.

get_content_disposition()

있다면 메시지의 Content-Disposition 헤더의 (매개 변수가 없는) 소문자 값을, 그렇지 않으면 None을 반환합니다. 메시지가 RFC 2183 [https://datatracker.ietf.org/doc/html/rfc2183.html]을 따른다면 이 메서드의 가능한 값은 inline, attachment 또는 None입니다.

Added in version 3.5.

walk()

walk() 메서드는 메시지 객체 트리의 모든 파트와 서브 파트를 깊이 우선 탐색 순서로 이터레이트 하는 데 사용할 수 있는 범용 제너레이터입니다. 일반적으로 walk()를 for 루프에서 이터레이터로 사용합니다; 각 이터레이션은 다음 서브 파트를 반환합니다.

다음은 멀티 파트 메시지 구조의 모든 파트에 대한 MIME 유형을 인쇄하는 예입니다:

>>> for part in msg.walk():
...     print(part.get_content_type())
multipart/report
text/plain
message/delivery-status
text/plain
text/plain
message/rfc822
text/plain

msg.get_content_maintype() == 'multipart'가 False를 반환하더라도, walk는 is_multipart()가 True를 반환하는 모든 파트의 서브 파트를 이터레이트 합니다. _structure 디버그 도우미 함수를 사용하여 예제에서 이를 확인할 수 있습니다:

>>> for part in msg.walk():
...     print(part.get_content_maintype() == 'multipart',
...           part.is_multipart())
True True
False False
False True
False False
False False
False True
False False
>>> _structure(msg)
multipart/report
    text/plain
    message/delivery-status
        text/plain
        text/plain
    message/rfc822
        text/plain

여기서 message 파트는 multiparts가 아니지만, 서브 파트를 포함합니다. is_multipart()는 True를 반환하고 walk는 서브 파트로 내려갑니다.

Message 객체는 MIME 메시지의 단순 텍스트를 생성할 때 사용할 수 있는 두 개의 인스턴스 어트리뷰트를 선택적으로 포함할 수 있습니다.

preamble

MIME 문서의 형식은 헤더 다음의 빈 줄과 첫 번째 멀티 파트 경계 문자열 사이에 일부 텍스트를 허용합니다. 일반적으로, 이 텍스트는 표준 MIME 장비를 벗어나기 때문에 MIME 인식 메일 리더에서 볼 수 없습니다. 그러나, 메시지의 원시 텍스트를 보거나, MIME을 인식하지 않는 리더에서 메시지를 볼 때, 이 텍스트가 보일 수 있습니다.

preamble 어트리뷰트에는 MIME 문서에 대한 이 선행 추가 텍스트가 포함됩니다. Parser가 헤더 다음이지만 첫 번째 경계 문자열 이전에 어떤 텍스트를 감지하면, 이 텍스트를 메시지의 preamble 어트리뷰트에 대입합니다. Generator가 MIME 메시지의 단순 텍스트 표현을 기록할 때, 메시지에 preamble 어트리뷰트가 있는 것을 발견하면, 헤더와 첫 번째 경계 사이의 영역에 이 텍스트를 기록합니다. 자세한 내용은 email.parser와 email.generator를 참조하십시오.

메시지 객체에 프리앰블이 없으면, preamble 어트리뷰트는 None이 됨에 유의하십시오.

epilogue

epilogue 어트리뷰트는 메시지의 마지막 경계와 끝 사이에 나타나는 텍스트를 포함한다는 점을 제외하고, preamble 어트리뷰트와 같은 방식으로 작동합니다.

Generator가 파일 끝에서 줄 넘김을 인쇄하도록 하기 위해 에필로그를 빈 문자열로 설정할 필요는 없습니다.

defects

defects 어트리뷰트는 이 메시지를 구문 분석할 때 발견된 모든 결함의 리스트를 포함합니다. 가능한 구문 분석 결함에 대한 자세한 설명은 email.errors를 참조하십시오.

email.mime: Creating email and MIME objects from scratch

소스 코드: Lib/email/mime/ [https://github.com/python/cpython/tree/main/Lib/email/mime/]

이 모듈은 레거시 (Compat32) 이메일 API의 일부입니다. 새로운 API에서는 기능이 contentmanager로 부분적으로 대체되지만, 특정 응용 프로그램에서는 이 클래스들이 레거시 코드가 아닌 곳에서도 여전히 유용할 수 있습니다.

일반적으로, 파일이나 일부 텍스트를, 텍스트를 구문 분석하고 루트 메시지 객체를 반환하는 구문 분석기에 전달하여 메시지 객체 구조를 얻습니다. 그러나 처음부터 완전한 메시지 구조를 만들거나, 개별 Message 객체를 직접 만들 수도 있습니다. 실제로, 기존 구조를 가져와서 새로운 Message 객체를 추가하거나 이동시킬 수도 있습니다. 이렇게 하면 MIME 메시지를 잘게 자르고 재배치하는 매우 편리한 인터페이스가 만들어집니다.

Message 인스턴스를 만들고 첨부 파일과 모든 적절한 헤더를 수동으로 추가하여 새 객체 구조를 만들 수 있습니다. 그러나 MIME 메시지의 경우, email 패키지는 작업을 쉽게 하기 위해 편리한 서브 클래스를 제공합니다.

클래스는 다음과 같습니다:

class email.mime.base.MIMEBase(_maintype, _subtype, *, policy=compat32, **_params)

모듈: email.mime.base

이것은 Message의 모든 MIME 특정 서브 클래스의 베이스 클래스입니다. 일반적으로, 할 수는 있지만, MIMEBase의 인스턴스를 만들지는 않습니다. MIMEBase는 주로 더 구체적인 MIME 인식 서브 클래스를 위한 편리한 베이스 클래스로 제공됩니다.

_maintype은 Content-Type 주 유형(예를 들어 text나 image)이고, _subtype은 Content-Type 부 유형(예를 들어 plain이나 gif)입니다. _params는 매개 변수 키/값 딕셔너리이며 Message.add_header로 직접 전달됩니다.

policy가 지정되면 (기본값은 compat32 정책입니다), Message로 전달됩니다.

MIMEBase 클래스는 항상 (_maintype, _subtype 및 _params에 기반하는) Content-Type 헤더와 (항상 1.0으로 설정되는) MIME-Version 헤더를 추가합니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.nonmultipart.MIMENonMultipart

모듈: email.mime.nonmultipart

MIMEBase의 서브 클래스, multipart 가 아닌 MIME 메시지의 중간 베이스 클래스입니다. 이 클래스의 기본 목적은 multipart 메시지에만 적합한 attach() 메서드 사용을 방지하는 것입니다. attach()가 호출되면 MultipartConversionError 예외가 발생합니다.

class email.mime.multipart.MIMEMultipart(_subtype='mixed', boundary=None, _subparts=None, *, policy=compat32, **_params)

모듈: email.mime.multipart

MIMEBase의 서브 클래스, multipart 인 MIME 메시지의 중간 베이스 클래스입니다. 선택적 _subtype의 기본값은 mixed이지만, 메시지의 부 유형을 지정하는 데 사용할 수 있습니다. multipart/_subtype의 Content-Type 헤더가 메시지 객체에 추가됩니다. MIME-Version 헤더도 추가됩니다.

선택적 boundary는 멀티 파트 경계 문자열입니다. None(기본값)이면, 경계는 필요할 때 (예를 들어 메시지가 직렬화될 때) 계산됩니다.

_subparts는 페이 로드의 초기 서브 파트 시퀀스입니다. 이 시퀀스를 리스트로 변환할 수 있어야 합니다. Message.attach 메서드를 사용하여 항상 메시지에 새 서브 파트를 첨부할 수 있습니다.

선택적 policy 인자의 기본값은 compat32입니다.

Content-Type 헤더에 대한 추가 매개 변수는 키워드 인자에서 취하거나, 키워드 딕셔너리인 _params 인자로 전달됩니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.application.MIMEApplication(_data, _subtype='octet-stream', _encoder=email.encoders.encode_base64, *, policy=compat32, **_params)

모듈: email.mime.application

A subclass of MIMENonMultipart, the MIMEApplication class is used to represent MIME message objects of major type application. _data contains the bytes for the raw application data. Optional _subtype specifies the MIME subtype and defaults to octet-stream.

선택적 _encoder는 전송을 위해 데이터의 실제 인코딩을 수행할 콜러블(즉, 함수)입니다. 이 콜러블은 MIMEApplication 인스턴스인 하나의 인자를 취합니다. 페이 로드를 인코딩된 형식으로 변경하려면 get_payload()와 set_payload()를 사용해야 합니다. 또한, 필요에 따라 Content-Transfer-Encoding이나 기타 헤더를 메시지 객체에 추가해야 합니다. 기본 인코딩은 base64입니다. 내장 인코더의 목록은 email.encoders 모듈을 참조하십시오.

선택적 policy 인자의 기본값은 compat32입니다.

_params는 베이스 클래스 생성자로 바로 전달됩니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.audio.MIMEAudio(_audiodata, _subtype=None, _encoder=email.encoders.encode_base64, *, policy=compat32, **_params)

모듈: email.mime.audio

A subclass of MIMENonMultipart, the MIMEAudio class is used to create MIME message objects of major type audio. _audiodata contains the bytes for the raw audio data. If this data can be decoded as au, wav, aiff, or aifc, then the subtype will be automatically included in the Content-Type header. Otherwise you can explicitly specify the audio subtype via the _subtype argument. If the minor type could not be guessed and _subtype was not given, then TypeError is raised.

선택적 _encoder는 전송을 위해 오디오 데이터의 실제 인코딩을 수행할 콜러블(즉, 함수)입니다. 이 콜러블은 MIMEAudio 인스턴스인 하나의 인자를 취합니다. 페이 로드를 인코딩된 형식으로 변경하려면 get_payload()와 set_payload()를 사용해야 합니다. 또한 필요에 따라 Content-Transfer-Encoding이나 기타 헤더를 메시지 객체에 추가해야 합니다. 기본 인코딩은 base64입니다. 내장 인코더의 목록은 email.encoders 모듈을 참조하십시오.

선택적 policy 인자의 기본값은 compat32입니다.

_params는 베이스 클래스 생성자로 바로 전달됩니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.image.MIMEImage(_imagedata, _subtype=None, _encoder=email.encoders.encode_base64, *, policy=compat32, **_params)

모듈: email.mime.image

A subclass of MIMENonMultipart, the MIMEImage class is used to create MIME message objects of major type image. _imagedata contains the bytes for the raw image data. If this data type can be detected (jpeg, png, gif, tiff, rgb, pbm, pgm, ppm, rast, xbm, bmp, webp, and exr attempted), then the subtype will be automatically included in the Content-Type header. Otherwise you can explicitly specify the image subtype via the _subtype argument. If the minor type could not be guessed and _subtype was not given, then TypeError is raised.

선택적 _encoder는 전송을 위해 이미지 데이터의 실제 인코딩을 수행할 콜러블(즉, 함수)입니다. 이 콜러블은 MIMEImage 인스턴스인 하나의 인자를 취합니다. 페이 로드를 인코딩된 형식으로 변경하려면 get_payload()와 set_payload()를 사용해야 합니다. 또한 필요에 따라 Content-Transfer-Encoding이나 기타 헤더를 메시지 객체에 추가해야 합니다. 기본 인코딩은 base64입니다. 내장 인코더의 목록은 email.encoders 모듈을 참조하십시오.

선택적 policy 인자의 기본값은 compat32입니다.

_params는 MIMEBase 생성자로 바로 전달됩니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.message.MIMEMessage(_msg, _subtype='rfc822', *, policy=compat32)

모듈: email.mime.message

MIMENonMultipart 의 서브 클래스, MIMEMessage 클래스는 주 유형 message의 MIME 객체를 만드는 데 사용됩니다. _msg는 페이 로드로 사용되며, Message 클래스(또는 그 서브 클래스)의 인스턴스여야 합니다, 그렇지 않으면 TypeError가 발생합니다.

선택적 _subtype은 메시지의 부 유형을 설정합니다; 기본값은 rfc822입니다.

선택적 policy 인자의 기본값은 compat32입니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

class email.mime.text.MIMEText(_text, _subtype='plain', _charset=None, *, policy=compat32)

모듈: email.mime.text

MIMENonMultipart 의 서브 클래스, MIMEText 클래스는 주 유형 text의 MIME 객체를 만드는 데 사용됩니다. _text는 페이 로드의 문자열입니다. _subtype은 부 유형이며 기본값은 plain입니다. _charset은 텍스트의 문자 집합이며 MIMENonMultipart 생성자에 인자로 전달됩니다; 기본값은 문자열에 ascii 코드 포인트만 포함되어 있으면 us-ascii이고, 그렇지 않으면 utf-8입니다. _charset 매개 변수는 문자열이나 Charset 인스턴스를 받아들입니다.

_charset 인자가 명시적으로 None으로 설정되어 있지 않은 한, 만들어진 MIMEText 객체에는 charset 매개 변수가 있는 Content-Type 헤더와 Content-Transfer-Encoding 헤더가 모두 있습니다. 이는 charset이 set_payload 명령으로 전달되더라도, 후속 set_payload 호출이 인코딩된 페이 로드를 만들지 않음을 의미합니다. Content-Transfer-Encoding 헤더를 삭제하여 이 동작을 “재설정”할 수 있으며, 그 후에 set_payload 호출은 자동으로 새 페이 로드를 인코딩합니다 (그리고 새 Content-Transfer-Encoding 헤더를 추가합니다).

선택적 policy 인자의 기본값은 compat32입니다.

버전 3.5에서 변경: _charset은 Charset 인스턴스도 받아들입니다.

버전 3.6에서 변경: policy 키워드 전용 매개 변수를 추가했습니다.

email.header: Internationalized headers

소스 코드: Lib/email/header.py [https://github.com/python/cpython/tree/main/Lib/email/header.py]

이 모듈은 레거시 (Compat32) 이메일 API의 일부입니다. 현재 API에서 헤더의 인코딩과 디코딩은 EmailMessage 클래스의 딕셔너리와 유사한 API에 의해 투명하게 처리됩니다. 레거시 코드에서 사용하는 것 외에도, 이 모듈은 헤더를 인코딩할 때 사용되는 문자 집합을 완전히 제어해야 하는 응용 프로그램에서 유용할 수 있습니다.

이 섹션의 나머지 텍스트는 모듈의 원본 설명서입니다.

RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]는 이메일 메시지 형식을 기술하는 기본 표준입니다. 대부분의 이메일이 ASCII 문자로만 구성된 당시에 널리 사용된 이전 RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] 표준에서 파생됩니다. RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]는 이메일에 7비트 ASCII 문자만 포함되어 있다고 가정한 명세입니다.

물론, 이메일이 전 세계에 배포되면서, 국제화되어 언어별 문자 집합을 이메일 메시지에 사용할 수 있게 되었습니다. 기본 표준에서는 여전히 7비트 ASCII 문자만 사용하여 이메일 메시지를 전송해야 하므로, ASCII가 아닌 문자가 포함된 이메일을 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 호환 형식으로 인코딩하는 방법을 설명하는 많은 RFC가 작성되었습니다. 이러한 RFC에는 RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html], RFC 2046 [https://datatracker.ietf.org/doc/html/rfc2046.html], RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 및 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]이 포함됩니다. email 패키지는 email.header와 email.charset 모듈에서 이러한 표준을 지원합니다.

이메일 헤더에 ASCII가 아닌 문자를 포함 시키려면 (가령 Subject나 To 필드에), Header 클래스를 사용하고 헤더 값에 문자열을 사용하는 대신 Message 객체의 필드를 Header 인스턴스로 대입해야 합니다. email.header 모듈에서 Header 클래스를 임포트 합니다. 예를 들면:

>>> from email.message import Message
>>> from email.header import Header
>>> msg = Message()
>>> h = Header('p\xf6stal', 'iso-8859-1')
>>> msg['Subject'] = h
>>> msg.as_string()
'Subject: =?iso-8859-1?q?p=F6stal?=\n\n'

Subject 필드에 비 ASCII 문자를 포함하기 위해 어떻게 했는지 아시겠습니까? 우리는 Header 인스턴스를 만들고 바이트 문자열이 인코딩된 문자 집합을 전달하여 이를 수행했습니다. 뒤에 Message 인스턴스가 평탄화될 때, Subject 필드는 올바르게 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 인코딩되었습니다. MIME 인식 메일 리더는 내장된 ISO-8859-1 문자를 사용하여 이 헤더를 표시하게 됩니다.

Header 클래스 설명은 다음과 같습니다:

class email.header.Header(s=None, charset=None, maxlinelen=None, header_name=None, continuation_ws=' ', errors='strict')

다른 문자 집합의 문자열을 포함할 수 있는 MIME 호환 헤더를 만듭니다.

선택적 s는 초기 헤더 값입니다. None(기본값)이면, 초기 헤더 값이 설정되지 않습니다. 나중에 append() 메서드 호출로 헤더에 추가할 수 있습니다. s는 bytes나 str의 인스턴스일 수 있지만, 의미에 대해서는 append() 설명서를 참조하십시오.

선택적 charset은 두 가지 용도로 사용됩니다: append() 메서드에 대한 charset 인자와 같은 의미입니다. 또한, charset 인자를 생략하는 모든 후속 append() 호출에 대한 기본 문자 집합을 설정합니다. charset이 생성자에 제공되지 않으면 (기본값), us-ascii 문자 집합이 s의 초기 문자 집합과 후속 append() 호출의 기본값으로 사용됩니다.

The maximum line length can be specified explicitly via maxlinelen. For splitting the first line to a shorter value (to account for the field header which isn’t included in s, e.g. Subject) pass in the name of the field in header_name. The default maxlinelen is 78, and the default value for header_name is None, meaning it is not taken into account for the first line of a long, split header.

선택적인 continuation_ws는 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 호환 접는 공백(folding whitespace)이어야하며, 일반적으로 스페이스나 하드 탭 문자입니다. 이 문자는 연속 줄 앞에 추가됩니다. continuation_ws는 기본적으로 단일 스페이스 문자입니다.

선택적 errors는 append() 메서드로 바로 전달됩니다.

append(s, charset=None, errors='strict')

문자열 s를 MIME 헤더에 추가합니다.

선택적인 charset(제공되면)은 Charset 인스턴스(email.charset을 참조하십시오)나 문자 집합의 이름이어야 하며, 이는 Charset 인스턴스로 변환됩니다. None(기본값) 값은 생성자에 지정된 charset이 사용됨을 의미합니다.

s는 bytes나 str의 인스턴스일 수 있습니다. bytes의 인스턴스이면, charset은 해당 바이트 문자열의 인코딩이며, 문자열을 해당 문자 집합으로 디코딩할 수 없으면 UnicodeError가 발생합니다.

s가 str의 인스턴스이면, charset은 문자열에 있는 문자의 문자 집합을 지정하는 힌트입니다.

두 경우 모두, RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 규칙을 사용하여 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 호환 헤더를 생성할 때, 문자열은 charset의 출력 코덱을 사용하여 인코딩됩니다. 출력 코덱을 사용하여 문자열을 인코딩할 수 없으면 UnicodeError가 발생합니다.

선택적 errors는 s가 바이트 문자열일 때 decode 호출에 errors 인자로 전달됩니다.

encode(splitchars=';, \t', maxlinelen=None, linesep='\n')

메시지 헤더를 RFC 호환 형식으로 인코딩합니다. 긴 줄을 래핑하고 비 ASCII 부분을 base64나 quoted-printable 인코딩으로 캡슐화할 수 있습니다.

선택적 splitchars는 일반 헤더 래핑 중 분할 알고리즘에 의해 추가 가중치를 받아야 하는 문자를 포함하는 문자열입니다. 이것은 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]의 ‘높은 수준의 구문 분할’을 아주 거칠게 지원합니다: 분할 문자 뒤에 오는 분리 점이 줄 분할 중에 선호되며, 문자열에 나타나는 순서대로 문자가 선호됩니다. 스페이스와 탭이 문자열에 포함되어 다른 분할 문자가 분할되는 줄에 나타나지 않을 때 분할 지점으로 어느 것을 선호해야 하는지를 나타낼 수 있습니다. Splitchars는 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 인코딩 된 줄에 영향을 미치지 않습니다.

주어지면, maxlinelen은 최대 줄 길이에 대한 인스턴스의 값을 대체합니다.

linesep은 접힌 헤더의 줄을 구분하는 데 사용되는 문자를 지정합니다. 기본적으로 파이썬 응용 프로그램 코드에 가장 유용한 값이지만 (\n), RFC 호환 줄 구분자로 헤더를 생성하기 위해 \r\n을 지정할 수 있습니다.

버전 3.2에서 변경: linesep 인자를 추가했습니다.

Header 클래스는 표준 연산자와 내장 함수를 지원하기 위한 많은 메서드도 제공합니다.

__str__()

무제한 줄 길이를 사용하여, Header의 근삿값을 문자열로 반환합니다. 모든 조각은 지정된 인코딩을 사용하여 유니코드로 변환되고 적절하게 결합합니다. 문자 집합이 'unknown-8bit' 인 조각은 'replace' 에러 처리기를 사용하여 ASCII로 디코딩됩니다.

버전 3.2에서 변경: 'unknown-8bit' 문자 집합에 대한 처리가 추가되었습니다.

__eq__(other)

이 메서드를 사용하면 두 개의 Header 인스턴스가 같은지 비교할 수 있습니다.

__ne__(other)

이 메서드를 사용하면 두 Header 인스턴스가 다른지 비교할 수 있습니다.

email.header 모듈은 다음과 같은 편의 함수도 제공합니다.

email.header.decode_header(header)

문자 집합을 변환하지 않고 메시지 헤더 값을 디코딩합니다. 헤더 값은 header에 있습니다.

이 함수는 헤더의 디코딩된 각 부분을 포함하는 (decoded_string, charset) 쌍의 리스트를 반환합니다. charset은 헤더의 인코딩되지 않은 부분에 대해 None이며, 그렇지 않으면 인코딩된 문자열에 지정된 문자 집합의 이름을 포함하는 소문자 문자열입니다.

예를 들면 다음과 같습니다:

>>> from email.header import decode_header
>>> decode_header('=?iso-8859-1?q?p=F6stal?=')
[(b'p\xf6stal', 'iso-8859-1')]

email.header.make_header(decoded_seq, maxlinelen=None, header_name=None, continuation_ws=' ')

decode_header()에 의해 반환된 것과 같은 쌍의 시퀀스로부터 Header 인스턴스를 만듭니다.

decode_header()는 헤더 값 문자열을 취하고 (decoded_string, charset) 형식의 쌍의 시퀀스를 반환합니다. 여기서 charset은 문자 집합의 이름입니다.

이 함수는 해당 쌍의 시퀀스 중 하나를 취해서 Header 인스턴스를 반환합니다. 선택적 maxlinelen, header_name 및 continuation_ws는 Header 생성자에서와 같습니다.

email.charset: Representing character sets

소스 코드: Lib/email/charset.py [https://github.com/python/cpython/tree/main/Lib/email/charset.py]

이 모듈은 레거시 (Compat32) 이메일 API의 일부입니다. 새 API에서는 별칭 표만 사용됩니다.

이 섹션의 나머지 텍스트는 모듈의 원본 설명서입니다.

이 모듈은 문자 집합 레지스트리와 이 레지스트리를 조작하기 위한 몇 가지 편의 메서드뿐만 아니라, 이메일 메시지의 문자 집합과 문자 집합 변환을 나타내는 Charset 클래스를 제공합니다. Charset 인스턴스는 email 패키지 내의 다른 여러 모듈에서 사용됩니다.

email.charset 모듈에서 이 클래스를 임포트 하십시오.

class email.charset.Charset(input_charset=DEFAULT_CHARSET)

문자 집합을 이메일 속성으로 매핑합니다.

이 클래스는 특정 문자 집합에 대해 이메일에 요구되는 요구 사항에 대한 정보를 제공합니다. 또한 해당 코덱을 사용할 수 있으면, 문자 집합 간 변환을 위한 편의 루틴을 제공합니다. 문자 집합이 주어지면, RFC 호환 방식으로 이메일 메시지에서 해당 문자 집합을 사용하는 방법에 대한 정보를 제공하는 데 최선을 다합니다.

이메일 헤더나 본문에 사용될 때 특정 문자 집합은 quoted-printable이나 base64로 인코딩해야 합니다. 특정 문자 집합은 완전히 변환해야 하며, 이메일에서는 허용되지 않습니다.

선택적 input_charset은 아래에 설명된 것과 같습니다; 항상 소문자로 강제 변환됩니다. 별칭이 정규화된 후에는 문자 집합 레지스트리에서 조회로 사용되어 문자 집합을 위해 사용할 헤더 인코딩, 본문 인코딩 및 출력 변환 코덱을 찾습니다. 예를 들어, input_charset이 iso-8859-1이면, 헤더와 본문은 quoted-printable을 사용하여 인코딩되며 출력 변환 코덱은 필요하지 않습니다. input_charset이 euc-jp면, 헤더는 base64로 인코딩되고, 본문은 인코딩되지 않지만, 출력 텍스트는 euc-jp 문자 집합에서 iso-2022-jp 문자 집합으로 변환됩니다.

Charset 인스턴스에는 다음과 같은 데이터 어트리뷰트가 있습니다:

input_charset

지정된 초기 문자 집합. 일반적인 별칭은 공식 이메일 이름으로 변환됩니다 (예를 들어 latin_1은 iso-8859-1로 변환됩니다). 기본값은 7비트 us-ascii입니다.

header_encoding

If the character set must be encoded before it can be used in an email header, this attribute will be set to charset.QP (for quoted-printable), charset.BASE64 (for base64 encoding), or charset.SHORTEST for the shortest of QP or BASE64 encoding. Otherwise, it will be None.

body_encoding

Same as header_encoding, but describes the encoding for the mail message’s body, which indeed may be different than the header encoding. charset.SHORTEST is not allowed for body_encoding.

output_charset

일부 문자 집합은 이메일 헤더나 본문에 사용하기 전에 변환해야 합니다. input_charset이 그중 하나이면, 이 어트리뷰트에는 출력이 변환될 문자 집합의 이름이 포함됩니다. 그렇지 않으면 None이 됩니다.

input_codec

input_charset을 유니코드로 변환하는 데 사용되는 파이썬 코덱의 이름. 변환 코덱이 필요하지 않으면, 이 어트리뷰트는 None입니다.

output_codec

유니코드를 output_charset으로 변환하는 데 사용되는 파이썬 코덱의 이름. 변환 코덱이 필요하지 않으면, 이 어트리뷰트의 값은 input_codec과 같습니다.

Charset 인스턴스에는 다음과 같은 메서드도 있습니다:

get_body_encoding()

본문 인코딩에 사용된 콘텐츠 전송 인코딩(content transfer encoding)을 반환합니다.

사용된 인코딩에 따라 문자열 quoted-printable이나 base64입니다. 또는 함수일 수 있는데, 이때는 인코딩되는 Message 객체를 단일 인자로 함수를 호출해야 합니다. 그러면 함수는 Content-Transfer-Encoding 헤더 자체를 적절한 것으로 설정해야 합니다.

body_encoding이 QP이면 문자열 quoted-printable을 반환하고, body_encoding이 BASE64이면 문자열 base64를 반환하고, 그렇지 않으면 문자열 7bit를 반환합니다.

get_output_charset()

출력 문자 집합을 반환합니다.

None이 아니라면 output_charset 어트리뷰트이고, 그렇지 않으면 input_charset입니다.

header_encode(string)

문자열 string을 헤더 인코딩합니다.

인코딩 유형(base64나 quoted-printable)은 header_encoding 어트리뷰트를 기반으로 합니다.

header_encode_lines(string, maxlengths)

string을 먼저 바이트열로 변환하여 헤더 인코딩합니다.

이는 문자열이 인자 maxlengths에 의해 주어진 최대 줄 길이에 맞춰진다는 점을 제외하고는 header_encode()와 유사합니다. maxlengths는 이터레이터여야 합니다: 이 이터레이터에서 반환된 각 요소는 다음 최대 줄 길이를 제공합니다.

body_encode(string)

문자열 string을 본문 인코딩합니다.

인코딩 유형(base64나 quoted-printable)은 body_encoding 어트리뷰트를 기반으로 합니다.

Charset 클래스는 표준 연산과 내장 함수를 지원하는 여러 가지 메서드도 제공합니다.

__str__()

Returns input_charset as a string coerced to lower case. __repr__() is an alias for __str__().

__eq__(other)

이 메서드를 사용하면 두 개의 Charset 인스턴스가 같은지 비교할 수 있습니다.

__ne__(other)

이 메서드를 사용하면 두 Charset 인스턴스가 다른지 비교할 수 있습니다.

email.charset 모듈은 또한 전역 문자 집합, 별명 및 코덱 레지스트리에 새 항목을 추가하기 위해 다음 함수를 제공합니다:

email.charset.add_charset(charset, header_enc=None, body_enc=None, output_charset=None)

전역 레지스트리에 문자 속성을 추가합니다.

charset은 입력 문자 집합이며, 문자 집합의 규범적 이름이어야 합니다.

Optional header_enc and body_enc is either charset.QP for quoted-printable, charset.BASE64 for base64 encoding, charset.SHORTEST for the shortest of quoted-printable or base64 encoding, or None for no encoding. SHORTEST is only valid for header_enc. The default is None for no encoding.

선택적 output_charset은 출력에 적용되어야 하는 문자 집합입니다. Charset.convert() 메서드가 호출될 때 입력 문자 집합에서 유니코드로, 다시 출력 문자 집합으로 변환이 진행됩니다. 기본값은 입력과 같은 문자 집합으로 출력하는 것입니다.

input_charset과 output_charset은 모두 모듈의 문자 집합에서 코덱으로의 매핑에 유니코드 코덱 항목이 있어야 합니다; add_codec()을 사용하여 모듈이 모르는 코덱을 추가하십시오. 자세한 내용은 codecs 모듈 설명서를 참조하십시오.

전역 문자 집합 레지스트리는 모듈 전역 딕셔너리 CHARSETS에 유지됩니다.

email.charset.add_alias(alias, canonical)

문자 집합 별칭을 추가합니다. alias는 별칭 이름입니다, 예를 들어 latin-1. canonical은 문자 집합의 규범적 이름입니다, 예를 들어 iso-8859-1.

전역 문자 집합 별칭 레지스트리는 모듈 전역 딕셔너리 ALIASES에 유지됩니다.

email.charset.add_codec(charset, codecname)

주어진 문자 집합의 문자를 유니코드와 매핑하는 코덱을 추가합니다.

charset은 문자 집합의 규범적 이름입니다. codecname은 str의 encode() 메서드의 두 번째 인자에 적합한 파이썬 코덱의 이름입니다.

email.encoders: Encoders

소스 코드: Lib/email/encoders.py [https://github.com/python/cpython/tree/main/Lib/email/encoders.py]

이 모듈은 레거시(Compat32) 이메일 API의 일부입니다. 새로운 API에서 기능은 set_content() 메서드의 cte 매개 변수에 의해 제공됩니다.

이 모듈은 파이썬 3에서 폐지되었습니다. MIMEText 클래스는 인스턴스 화 중에 전달된 _subtype과 _charset 값을 사용하여 콘텐츠 유형과 CTE 헤더를 설정하므로 여기에 제공된 함수를 명시적으로 호출하면 안 됩니다.

이 섹션의 나머지 텍스트는 모듈의 원본 설명서입니다.

Message 객체를 처음부터 만들 때, 종종 호환 메일 서버를 통한 전송을 위해 페이 로드를 인코딩해야 합니다. 바이너리 데이터가 포함된 image/*와 text/* 유형 메시지의 경우 특히 그렇습니다.

The email package provides some convenient encoders in its encoders module. These encoders are actually used by the MIMEAudio and MIMEImage class constructors to provide default encodings. All encoder functions take exactly one argument, the message object to encode. They usually extract the payload, encode it, and reset the payload to this newly encoded value. They should also set the Content-Transfer-Encoding header as appropriate.

이러한 함수는 멀티 파트 메시지에는 의미가 없음에 유의하십시오. 대신 개별 서브 파트에 적용해야 하며, 유형이 멀티 파트인 메시지를 전달하면 TypeError가 발생합니다.

제공되는 인코딩 함수는 다음과 같습니다:

email.encoders.encode_quopri(msg)

페이 로드를 인용 quoted-printable 형식으로 인코딩하고 Content-Transfer-Encoding 헤더를 quoted-printable로 설정합니다 [1]. 이것은 대부분의 페이 로드가 인쇄 가능한 일반 데이터이지만, 인쇄할 수 없는 문자가 몇 개 있을 때 사용하기에 적합한 인코딩입니다.

email.encoders.encode_base64(msg)

페이 로드를 base64 형식으로 인코딩하고 Content-Transfer-Encoding 헤더를 base64로 설정합니다. 이것은 페이 로드가 대부분 인쇄할 수 없는 데이터일 때 사용하기에 좋은 인코딩입니다. quoted-printable보다 더 압축된 형식이기 때문입니다. base64 인코딩의 단점은 텍스트를 사람이 읽을 수 없도록 만든다는 것입니다.

email.encoders.encode_7or8bit(msg)

이것은 실제로 메시지의 페이 로드를 수정하지는 않지만, 페이 로드 데이터를 기반으로, Content-Transfer-Encoding 헤더를 적절하게 7bit나 8bit로 설정합니다.

email.encoders.encode_noop(msg)

이것은 아무것도 하지 않습니다. 심지어 Content-Transfer-Encoding 헤더도 설정하지 않습니다.

각주

[1]

encode_quopri()로 인코딩하면 데이터의 모든 탭과 공백 문자도 인코딩됨에 유의하십시오.

email.utils: Miscellaneous utilities

소스 코드: Lib/email/utils.py [https://github.com/python/cpython/tree/main/Lib/email/utils.py]

email.utils 모듈에서 제공되는 몇 가지 유용한 유틸리티가 있습니다:

email.utils.localtime(dt=None)

Return local time as an aware datetime object. If called without arguments, return current time. Otherwise dt argument should be a datetime instance, and it is converted to the local time zone according to the system time zone database. If dt is naive (that is, dt.tzinfo is None), it is assumed to be in local time.

Added in version 3.3.

Deprecated since version 3.12, removed in version 3.14: The isdst parameter.

email.utils.make_msgid(idstring=None, domain=None)

RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]-준수 Message-ID 헤더에 적합한 문자열을 반환합니다. 선택적인 idstring이 주어지면, 메시지 id의 고유성을 강화하는 데 사용되는 문자열입니다. 선택적인 domain이 주어지면, msgid의 ‘@’ 다음 부분을 제공합니다. 기본값은 로컬 호스트 명입니다. 일반적으로 이 기본값을 재정의할 필요는 없지만, 여러 호스트에 걸쳐 일관된 도메인 이름을 사용하는 분산 시스템을 구성하는 경우와 같이 특정 경우에 유용할 수 있습니다.

버전 3.2에서 변경: domain 키워드가 추가되었습니다.

나머지 함수는 레거시 (Compat32) email API의 일부입니다. 이것들이 제공하는 구문 분석과 포매팅은 새 API의 헤더 구문 분석 장치가 자동으로 수행하므로, 새 API에서 이것들을 직접 사용할 필요는 없습니다.

email.utils.quote(str)

str에 있는 역 슬래시를 두 개의 역 슬래시로 대체하고, 큰따옴표는 역 슬래시-큰따옴표로 대체한 새 문자열을 반환합니다.

email.utils.unquote(str)

str의 unquote 된 버전인 새 문자열을 반환합니다. str가 큰따옴표로 끝나고 시작하면, 큰따옴표가 제거됩니다. 마찬가지로 str이 화살괄호(angle brackets)로 끝나고 시작하면, 제거됩니다.

email.utils.parseaddr(address, *, strict=True)

address(To나 Cc와 같은 주소를 포함하는 필드의 값이어야 합니다)를 realname과 email 주소 구성 요소로 구문 분석합니다. 구문 분석에 실패하지 않는 한 해당 정보의 튜플을 반환합니다. 실패하면 ('', '')의 2-튜플이 반환됩니다.

If strict is true, use a strict parser which rejects malformed inputs.

버전 3.13에서 변경: Add strict optional parameter and reject malformed inputs by default.

email.utils.formataddr(pair, charset='utf-8')

parseaddr()의 역, (realname, email_address) 형식의 2-튜플을 취해 To나 Cc 헤더에 적합한 문자열 값을 반환합니다. pair의 첫 번째 요소가 거짓이면, 두 번째 요소는 수정되지 않은 채 반환됩니다.

선택적 charset은 realname에 비 ASCII 문자가 포함되어있을 때 realname의 RFC 2047 [https://datatracker.ietf.org/doc/html/rfc2047.html] 인코딩에 사용될 문자 집합입니다. str이나 Charset의 인스턴스가 될 수 있습니다. 기본값은 utf-8입니다.

버전 3.3에서 변경: charset 옵션이 추가되었습니다.

email.utils.getaddresses(fieldvalues, *, strict=True)

This method returns a list of 2-tuples of the form returned by parseaddr(). fieldvalues is a sequence of header field values as might be returned by Message.get_all.

If strict is true, use a strict parser which rejects malformed inputs.

Here’s a simple example that gets all the recipients of a message:

from email.utils import getaddresses

tos = msg.get_all('to', [])
ccs = msg.get_all('cc', [])
resent_tos = msg.get_all('resent-to', [])
resent_ccs = msg.get_all('resent-cc', [])
all_recipients = getaddresses(tos + ccs + resent_tos + resent_ccs)

버전 3.13에서 변경: Add strict optional parameter and reject malformed inputs by default.

email.utils.parsedate(date)

RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]의 규칙에 따라 날짜를 구문 분석하려고 시도합니다. 그러나, 일부 메일러는 지정된 대로 이 형식을 따르지 않으므로 parsedate()는 이러한 경우에 올바르게 추측하려고 합니다. date는 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 날짜를 포함하는 문자열입니다 (가령 "Mon, 20 Nov 1995 19:12:08 -0500"). 날짜 구문 분석에 성공하면, parsedate()는 time.mktime()에 직접 전달할 수 있는 9-튜플을 반환합니다; 그렇지 않으면, None을 반환합니다. 결과 튜플의 인덱스 6, 7 및 8은 사용할 수 없음에 유의하십시오.

email.utils.parsedate_tz(date)

parsedate()와 같은 기능을 수행하지만, None이나 10-튜플을 반환합니다; 앞의 9개 요소는 time.mktime()에 직접 전달할 수 있는 튜플을 구성하고, 열 번째 요소는 UTC(그리니치 표준 시의 공식 용어)로부터의 날짜의 시간대 오프셋입니다 [1]. 입력 문자열에 시간대가 없으면, 반환되는 튜플의 마지막 요소는 0입니다, UTC를 나타냅니다. 결과 튜플의 인덱스 6, 7 및 8은 사용할 수 없음에 유의하십시오.

email.utils.parsedate_to_datetime(date)

The inverse of format_datetime(). Performs the same function as parsedate(), but on success returns a datetime; otherwise ValueError is raised if date contains an invalid value such as an hour greater than 23 or a timezone offset not between -24 and 24 hours. If the input date has a timezone of -0000, the datetime will be a naive datetime, and if the date is conforming to the RFCs it will represent a time in UTC but with no indication of the actual source timezone of the message the date comes from. If the input date has any other valid timezone offset, the datetime will be an aware datetime with the corresponding a timezone tzinfo.

Added in version 3.3.

email.utils.mktime_tz(tuple)

parsedate_tz()에 의해 반환된 10-튜플을 UTC 타임스탬프(Epoch 이후 초)로 바꿉니다. 튜플의 시간대 항목이 None이면, 지역 시간으로 간주합니다.

email.utils.formatdate(timeval=None, localtime=False, usegmt=False)

RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]에 따르는 날짜 문자열을 반환합니다, 예를 들어:

Fri, 09 Nov 2001 01:08:47 -0000

Optional timeval if given is a floating-point time value as accepted by time.gmtime() and time.localtime(), otherwise the current time is used.

선택적 localtime 은, True일 때, timeval을 해석하고, UTC 대신 일광 절약 시간을 적절히 고려하는 지역 시간대에 상대적인 날짜를 반환토록 하는 플래그입니다. 기본값은 UTC가 사용된다는 뜻인 False입니다.

선택적 usegmt는, True일 때, 날짜 문자열의 시간대를 숫자 -0000 대신 ASCII 문자열 GMT로 출력하도록 하는 플래그입니다. 일부 프로토콜(가령 HTTP)에 필요합니다. 이것은 localtime 이 False일 때만 적용됩니다. 기본값은 False입니다.

email.utils.format_datetime(dt, usegmt=False)

formatdate와 같지만, 입력이 datetime 인스턴스입니다. 나이브 datetime이면, “소스 시간대에 대한 정보가 없는 UTC”로 간주하며, 관습적으로 -0000이 시간대로 사용됩니다. 어웨어 datetime이면, 숫자 시간대 오프셋이 사용됩니다. 오프셋이 0인 어웨어 시간대면, usegmt를 True로 설정해서 GMT 문자열을 숫자 시간대 오프셋 대신 사용할 수 있습니다. 이것은 표준을 준수하는 HTTP date 헤더를 생성하는 방법을 제공합니다.

Added in version 3.3.

email.utils.decode_rfc2231(s)

RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]에 따라 s 문자열을 디코드합니다.

email.utils.encode_rfc2231(s, charset=None, language=None)

RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]에 따라 s 문자열을 인코드합니다. 선택적인 charset과 language가 주어지면, 사용할 문자 집합 이름과 언어 이름입니다. 둘 다 지정되지 않으면, s가 그대로 반환됩니다. charset이 주어졌지만, language가 지정되지 않으면, 문자열은 language에 대해 빈 문자열을 사용하여 인코딩됩니다.

email.utils.collapse_rfc2231_value(value, errors='replace', fallback_charset='us-ascii')

header 매개 변수가 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]로 인코딩되었을 때, Message.get_param은 문자 집합, 언어 및 값이 포함된 3-튜플을 반환할 수 있습니다. collapse_rfc2231_value()는 이것을 유니코드 문자열로 변환합니다. 선택적 errors는 str의 encode() 메서드의 errors 인자로 전달됩니다; 기본값은 'replace'입니다. 선택적 fallback_charset은 RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html] 헤더에 있는 것이 파이썬에 알려지지 않았을 때 사용할 문자 집합을 지정합니다; 기본값은 'us-ascii'입니다.

편의상, collapse_rfc2231_value()에 전달된 value가 튜플이 아니면, 문자열이어야 하고 unquote 되어 반환됩니다.

email.utils.decode_params(params)

RFC 2231 [https://datatracker.ietf.org/doc/html/rfc2231.html]에 따라 매개 변수 리스트를 디코드합니다. params는 (content-type, string-value) 형식의 요소를 포함하는 2-튜플의 시퀀스입니다.

각주

[1]

시간대 오프셋의 부호는 같은 시간대에 대한 time.timezone 변수의 부호와 반대임에 유의하십시오; 이 모듈이 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]를 따르지만, 후자의 변수는 POSIX 표준을 따릅니다.

email.iterators: Iterators

소스 코드: Lib/email/iterators.py [https://github.com/python/cpython/tree/main/Lib/email/iterators.py]

메시지 객체 트리를 이터레이트 하는 것은 Message.walk 메서드를 사용하면 매우 쉽습니다. email.iterators 모듈은 메시지 객체 트리에 대한 유용한 고수준 이터레이션을 제공합니다.

email.iterators.body_line_iterator(msg, decode=False)

msg의 모든 서브 파트에 있는 모든 페이 로드를 이터레이트 하여, 문자열 페이 로드를 한 줄씩 반환합니다. 모든 서브 파트 헤더를 건너뛰고, 파이썬 문자열이 아닌 페이 로드가 있는 서브 파트를 건너뜁니다. 이는 readline()을 사용하여 파일에서 메시지의 평평한(flat) 텍스트 표현을 읽는 것과 다소 유사하며, 모든 중간 헤더를 건너뜁니다.

선택적 decode는 Message.get_payload로 전달됩니다.

email.iterators.typed_subpart_iterator(msg, maintype='text', subtype=None)

msg의 모든 서브 파트를 이터레이트 하여, maintype과 subtype으로 지정된 MIME 유형과 일치하는 서브 파트만 반환합니다.

subtype은 선택적임에 유의하십시오; 생략하면, 서브 파트 MIME 형식 일치는 메인 형식으로만 수행됩니다. maintype도 선택적입니다; 기본값은 text입니다.

따라서, 기본적으로 typed_subpart_iterator()는 MIME 유형이 text/* 인 각 서브 파트를 반환합니다.

유용한 디버깅 도구로 다음 함수가 추가되었습니다. 이것은 패키지에서 지원되는 공용 인터페이스의 일부로 간주하지 않아야 합니다.

email.iterators._structure(msg, fp=None, level=0, include_default=False)

메시지 객체 구조의 콘텐츠 유형을 들여쓰기하여 인쇄합니다. 예를 들면:

>>> msg = email.message_from_file(somefile)
>>> _structure(msg)
multipart/mixed
    text/plain
    text/plain
    multipart/digest
        message/rfc822
            text/plain
        message/rfc822
            text/plain
        message/rfc822
            text/plain
        message/rfc822
            text/plain
        message/rfc822
            text/plain
    text/plain

선택적 fp는 출력을 인쇄할 파일류 객체입니다. 파이썬의 print() 함수에 적합해야 합니다. level은 내부적으로 사용됩니다. include_default가 참이면, 기본 유형도 인쇄합니다.

json — JSON encoder and decoder

소스 코드: Lib/json/__init__.py [https://github.com/python/cpython/tree/main/Lib/json/__init__.py]

JSON (JavaScript Object Notation) [https://json.org], specified by RFC 7159 [https://datatracker.ietf.org/doc/html/rfc7159.html] (which obsoletes RFC 4627 [https://datatracker.ietf.org/doc/html/rfc4627.html]) and by ECMA-404 [https://ecma-international.org/publications-and-standards/standards/ecma-404/], is a lightweight data interchange format inspired by JavaScript [https://en.wikipedia.org/wiki/JavaScript] object literal syntax (although it is not a strict subset of JavaScript [1] ).

경고

Be cautious when parsing JSON data from untrusted sources. A malicious JSON string may cause the decoder to consume considerable CPU and memory resources. Limiting the size of data to be parsed is recommended.

json은 표준 라이브러리 marshal과 pickle 모듈 사용자에게 익숙한 API를 제공합니다.

기본 파이썬 객체 계층 구조 인코딩:

>>> import json
>>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
'["foo", {"bar": ["baz", null, 1.0, 2]}]'
>>> print(json.dumps("\"foo\bar"))
"\"foo\bar"
>>> print(json.dumps('\u1234'))
"\u1234"
>>> print(json.dumps('\\'))
"\\"
>>> print(json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True))
{"a": 0, "b": 0, "c": 0}
>>> from io import StringIO
>>> io = StringIO()
>>> json.dump(['streaming API'], io)
>>> io.getvalue()
'["streaming API"]'

간결한 인코딩:

>>> import json
>>> json.dumps([1, 2, 3, {'4': 5, '6': 7}], separators=(',', ':'))
'[1,2,3,{"4":5,"6":7}]'

예쁜 인쇄:

>>> import json
>>> print(json.dumps({'6': 7, '4': 5}, sort_keys=True, indent=4))
{
    "4": 5,
    "6": 7
}

Specializing JSON object encoding:

>>> import json
>>> def custom_json(obj):
...     if isinstance(obj, complex):
...         return {'__complex__': True, 'real': obj.real, 'imag': obj.imag}
...     raise TypeError(f'Cannot serialize object of {type(obj)}')
...
>>> json.dumps(1 + 2j, default=custom_json)
'{"__complex__": true, "real": 1.0, "imag": 2.0}'

JSON 디코딩:

>>> import json
>>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
['foo', {'bar': ['baz', None, 1.0, 2]}]
>>> json.loads('"\\"foo\\bar"')
'"foo\x08ar'
>>> from io import StringIO
>>> io = StringIO('["streaming API"]')
>>> json.load(io)
['streaming API']

JSON 객체 디코딩 특수화:

>>> import json
>>> def as_complex(dct):
...     if '__complex__' in dct:
...         return complex(dct['real'], dct['imag'])
...     return dct
...
>>> json.loads('{"__complex__": true, "real": 1, "imag": 2}',
...     object_hook=as_complex)
(1+2j)
>>> import decimal
>>> json.loads('1.1', parse_float=decimal.Decimal)
Decimal('1.1')

JSONEncoder 확장하기:

>>> import json
>>> class ComplexEncoder(json.JSONEncoder):
...     def default(self, obj):
...         if isinstance(obj, complex):
...             return [obj.real, obj.imag]
...         # Let the base class default method raise the TypeError
...         return super().default(obj)
...
>>> json.dumps(2 + 1j, cls=ComplexEncoder)
'[2.0, 1.0]'
>>> ComplexEncoder().encode(2 + 1j)
'[2.0, 1.0]'
>>> list(ComplexEncoder().iterencode(2 + 1j))
['[2.0', ', 1.0', ']']

Using json from the shell to validate and pretty-print:

$ echo '{"json":"obj"}' | python -m json
{
    "json": "obj"
}
$ echo '{1.2:3.4}' | python -m json
Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

자세한 설명은 Command-line interface를 참조하십시오.

참고

JSON is a subset of YAML [https://yaml.org/] 1.2. The JSON produced by this module’s default settings (in particular, the default separators value) is also a subset of YAML 1.0 and 1.1. This module can thus also be used as a YAML serializer.

참고

이 모듈의 인코더와 디코더는 기본적으로 입력과 출력 순서를 유지합니다. 하부 컨테이너에 순서가 없을 때만 순서가 손실됩니다.

기본 사용법

json.dump(obj, fp, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw)

이 변환표를 사용하여 obj를 JSON 형식 스트림으로 fp(.write()를 지원하는 파일류 객체)로 직렬화합니다.

skipkeys가 참이면 (기본값: False), 기본형(str, int, float, bool, None)이 아닌 딕셔너리 키는 TypeError를 발생시키는 대신 건너뜁니다.

json 모듈은 항상 bytes 객체가 아니라 str 객체를 생성합니다. 따라서, fp.write()는 str 입력을 지원해야 합니다.

ensure_ascii가 참(기본값)이면, 출력에서 모든 비 ASCII 문자가 이스케이프 되도록 보장됩니다. ensure_ascii가 거짓이면, 그 문자들은 있는 그대로 출력됩니다.

If check_circular is false (default: True), then the circular reference check for container types will be skipped and a circular reference will result in a RecursionError (or worse).

allow_nan이 거짓이면 (기본값: True), JSON 사양을 엄격히 준수하여 범위를 벗어난 float 값(nan, inf, -inf)을 직렬화하면 ValueError를 일으킵니다. allow_nan이 참이면, JavaScript의 대응 물(NaN, Infinity, -Infinity)이 사용됩니다.

indent가 음이 아닌 정수나 문자열이면, JSON 배열 요소와 오브젝트 멤버가 해당 들여쓰기 수준으로 예쁘게 인쇄됩니다. 0, 음수 또는 ""의 들여쓰기 수준은 줄 넘김만 삽입합니다. None(기본값)은 가장 간결한(compact) 표현을 선택합니다. 양의 정수 indent를 사용하면, 수준 당 그만큼의 스페이스로 들여쓰기합니다. indent가 문자열이면 (가령 "\t"), 각 수준을 들려 쓰는 데 그 문자열을 사용합니다.

버전 3.2에서 변경: indent에 정수뿐만 아니라 문자열을 허용합니다.

지정되면, separators는 (item_separator, key_separator) 튜플이어야 합니다. 기본값은 indent가 None이면 (', ', ': ')이고, 그렇지 않으면 (',', ': ')입니다. 가장 간결한 JSON 표현을 얻으려면, (',', ':')를 지정하여 공백을 제거해야 합니다.

버전 3.4에서 변경: indent가 None이 아니면, (',', ': ')를 기본값으로 사용합니다.

지정되면, default는 달리 직렬화할 수 없는 객체에 대해 호출되는 함수여야 합니다. 객체의 JSON 인코딩 가능한 버전을 반환하거나 TypeError를 발생시켜야 합니다. 지정하지 않으면, TypeError가 발생합니다.

sort_keys가 참이면 (기본값: False), 딕셔너리의 출력이 키로 정렬됩니다.

To use a custom JSONEncoder subclass (e.g. one that overrides the default() method to serialize additional types), specify it with the cls kwarg; otherwise JSONEncoder is used.

버전 3.6에서 변경: 모든 선택적 매개 변수는 이제 키워드-전용입니다.

참고

pickle과 marshal과 달리, JSON은 프레임 프로토콜이 아니므로 같은 fp를 사용하여 dump()를 반복 호출하여 여러 객체를 직렬화하려고 하면 잘못된 JSON 파일이 생성됩니다.

json.dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw)

이 변환표를 사용하여 obj를 JSON 형식의 str로 직렬화합니다. 인자는 dump()에서와 같은 의미입니다.

참고

JSON의 키/값 쌍에 있는 키는 항상 str 형입니다. 딕셔너리를 JSON으로 변환하면, 딕셔너리의 모든 키가 문자열로 강제 변환됩니다. 이것의 결과로, 딕셔너리를 JSON으로 변환한 다음 다시 딕셔너리로 변환하면, 딕셔너리가 원래의 것과 같지 않을 수 있습니다. 즉, x에 비 문자열 키가 있으면 loads(dumps(x)) != x입니다.

json.load(fp, *, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)

이 변환표를 사용하여 fp(JSON 문서를 포함하는 .read()를 지원하는 텍스트 파일이나 바이너리 파일)를 파이썬 객체로 역 직렬화합니다.

object_hook is an optional function that will be called with the result of any object literal decoded (a dict). The return value of object_hook will be used instead of the dict. This feature can be used to implement custom decoders (e.g. JSON-RPC [https://www.jsonrpc.org] class hinting).

object_pairs_hook is an optional function that will be called with the result of any object literal decoded with an ordered list of pairs. The return value of object_pairs_hook will be used instead of the dict. This feature can be used to implement custom decoders. If object_hook is also defined, the object_pairs_hook takes priority.

버전 3.1에서 변경: object_pairs_hook에 대한 지원이 추가되었습니다.

parse_float is an optional function that will be called with the string of every JSON float to be decoded. By default, this is equivalent to float(num_str). This can be used to use another datatype or parser for JSON floats (e.g. decimal.Decimal).

parse_int is an optional function that will be called with the string of every JSON int to be decoded. By default, this is equivalent to int(num_str). This can be used to use another datatype or parser for JSON integers (e.g. float).

버전 3.11에서 변경: The default parse_int of int() now limits the maximum length of the integer string via the interpreter’s integer string conversion length limitation to help avoid denial of service attacks.

parse_constant is an optional function that will be called with one of the following strings: '-Infinity', 'Infinity', 'NaN'. This can be used to raise an exception if invalid JSON numbers are encountered.

버전 3.1에서 변경: parse_constant는 더는 ‘null’, ‘true’, ‘false’에 대해 호출되지 않습니다.

사용자 정의 JSONDecoder 서브 클래스를 사용하려면, cls 키워드 인자로 지정하십시오; 그렇지 않으면 JSONDecoder가 사용됩니다. 추가 키워드 인자는 클래스 생성자에 전달됩니다.

역 직렬화되는 데이터가 유효한 JSON 문서가 아니면, JSONDecodeError가 발생합니다.

버전 3.6에서 변경: 모든 선택적 매개 변수는 이제 키워드-전용입니다.

버전 3.6에서 변경: fp는 이제 바이너리 파일이 될 수 있습니다. 입력 인코딩은 UTF-8, UTF-16 또는 UTF-32 여야 합니다.

json.loads(s, *, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)

이 변환표를 사용하여 s(JSON 문서를 포함하는 str, bytes 또는 bytearray 인스턴스)를 파이썬 객체로 역 직렬화합니다.

다른 인자는 load()와 같은 의미를 가집니다.

역 직렬화되는 데이터가 유효한 JSON 문서가 아니면, JSONDecodeError가 발생합니다.

버전 3.6에서 변경: s는 이제 bytes나 bytearray 형일 수 있습니다. 입력 인코딩은 UTF-8, UTF-16 또는 UTF-32 여야 합니다.

버전 3.9에서 변경: 키워드 인자 encoding이 제거되었습니다.

인코더와 디코더

class json.JSONDecoder(*, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, strict=True, object_pairs_hook=None)

간단한 JSON 디코더.

기본적으로 디코딩할 때 다음과 같은 변환을 수행합니다:

JSON

파이썬

오브젝트(object)

dict

배열(array)

list

문자열(string)

str

숫자 (정수)

int

숫자 (실수)

float

true

True

false

False

null

None

또한, NaN, Infinity 및 -Infinity를 해당 float 값으로 이해합니다. 이 값은 JSON 명세에 속하지 않습니다.

object_hook is an optional function that will be called with the result of every JSON object decoded and its return value will be used in place of the given dict. This can be used to provide custom deserializations (e.g. to support JSON-RPC [https://www.jsonrpc.org] class hinting).

object_pairs_hook is an optional function that will be called with the result of every JSON object decoded with an ordered list of pairs. The return value of object_pairs_hook will be used instead of the dict. This feature can be used to implement custom decoders. If object_hook is also defined, the object_pairs_hook takes priority.

버전 3.1에서 변경: object_pairs_hook에 대한 지원이 추가되었습니다.

parse_float is an optional function that will be called with the string of every JSON float to be decoded. By default, this is equivalent to float(num_str). This can be used to use another datatype or parser for JSON floats (e.g. decimal.Decimal).

parse_int is an optional function that will be called with the string of every JSON int to be decoded. By default, this is equivalent to int(num_str). This can be used to use another datatype or parser for JSON integers (e.g. float).

parse_constant is an optional function that will be called with one of the following strings: '-Infinity', 'Infinity', 'NaN'. This can be used to raise an exception if invalid JSON numbers are encountered.

strict가 거짓이면 (True가 기본값입니다), 문자열 안에 제어 문자가 허용됩니다. 이 문맥에서 제어 문자는 0–31 범위의 문자 코드를 가진 것들인데, '\t' (탭), '\n', '\r' 및 '\0'을 포함합니다.

역 직렬화되는 데이터가 유효한 JSON 문서가 아니면, JSONDecodeError가 발생합니다.

버전 3.6에서 변경: 모든 매개 변수가 이제 키워드-전용입니다.

decode(s)

s(JSON 문서가 포함된 str 인스턴스)의 파이썬 표현을 반환합니다.

주어진 JSON 문서가 유효하지 않으면 JSONDecodeError가 발생합니다.

raw_decode(s)

s(JSON 문서로 시작하는 str)에서 JSON 문서를 디코딩하고, 파이썬 표현과 문서가 끝난 s에서의 인덱스로 구성된 2-튜플을 반환합니다.

끝에 여분의 데이터가 있을 수 있는 문자열에서 JSON 문서를 디코딩하는 데 사용할 수 있습니다.

class json.JSONEncoder(*, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, sort_keys=False, indent=None, separators=None, default=None)

파이썬 데이터 구조를 위한 확장 가능한 JSON 인코더

기본적으로 다음 객체와 형을 지원합니다.:

파이썬

JSON

dict

오브젝트(object)

list, tuple

배열(array)

str

문자열(string)

int, float, int와 float에서 파생된 열거형

숫자(number)

True

true

False

false

None

null

버전 3.4에서 변경: int와 float 파생 Enum 클래스에 대한 지원이 추가되었습니다.

To extend this to recognize other objects, subclass and implement a default() method with another method that returns a serializable object for o if possible, otherwise it should call the superclass implementation (to raise TypeError).

skipkeys가 거짓(기본값)이면, str, int, float 또는 None이 아닌 키를 인코딩하려고 시도할 때 TypeError가 발생합니다. skipkeys가 참이면 이러한 항목은 단순히 건너뜁니다.

ensure_ascii가 참(기본값)이면, 출력에서 모든 비 ASCII 문자가 이스케이프 되도록 보장됩니다. ensure_ascii가 거짓이면, 그 문자들은 있는 그대로 출력됩니다.

If check_circular is true (the default), then lists, dicts, and custom encoded objects will be checked for circular references during encoding to prevent an infinite recursion (which would cause a RecursionError). Otherwise, no such check takes place.

allow_nan이 참(기본값)이면, NaN, Infinity 및 -Infinity는 그 자체로 인코딩됩니다. 이 동작은 JSON 사양을 따르지 않지만, 대부분의 JavaScript 기반 인코더 및 디코더와 일치합니다. 그렇지 않으면, 그러한 float를 인코딩하는 것은 ValueError가 됩니다.

sort_keys가 참(기본값: False)이면, 딕셔너리의 출력이 키로 정렬됩니다; JSON 직렬화를 이전과 비교할 수 있도록 해서 회귀 테스트에 유용합니다.

indent가 음이 아닌 정수나 문자열이면, JSON 배열 요소와 오브젝트 멤버가 해당 들여쓰기 수준으로 예쁘게 인쇄됩니다. 0, 음수 또는 ""의 들여쓰기 수준은 줄 넘김만 삽입합니다. None(기본값)은 가장 간결한(compact) 표현을 선택합니다. 양의 정수 indent를 사용하면, 수준 당 그만큼의 스페이스로 들여쓰기합니다. indent가 문자열이면 (가령 "\t"), 각 수준을 들려 쓰는 데 그 문자열을 사용합니다.

버전 3.2에서 변경: indent에 정수뿐만 아니라 문자열을 허용합니다.

지정되면, separators는 (item_separator, key_separator) 튜플이어야 합니다. 기본값은 indent가 None이면 (', ', ': ')이고, 그렇지 않으면 (',', ': ')입니다. 가장 간결한 JSON 표현을 얻으려면, (',', ':')를 지정하여 공백을 제거해야 합니다.

버전 3.4에서 변경: indent가 None이 아니면, (',', ': ')를 기본값으로 사용합니다.

지정되면, default는 달리 직렬화할 수 없는 객체에 대해 호출되는 함수여야 합니다. 객체의 JSON 인코딩 가능한 버전을 반환하거나 TypeError를 발생시켜야 합니다. 지정하지 않으면, TypeError가 발생합니다.

버전 3.6에서 변경: 모든 매개 변수가 이제 키워드-전용입니다.

default(o)

o의 직렬화 가능 객체를 반환하거나 (TypeError를 발생시키기 위해서) 베이스 구현을 호출하도록 서브 클래스에 이 메서드를 구현하십시오.

For example, to support arbitrary iterators, you could implement default() like this:

def default(self, o):
   try:
       iterable = iter(o)
   except TypeError:
       pass
   else:
       return list(iterable)
   # Let the base class default method raise the TypeError
   return super().default(o)

encode(o)

파이썬 데이터 구조 o의 JSON 문자열 표현을 반환합니다. 예를 들면:

>>> json.JSONEncoder().encode({"foo": ["bar", "baz"]})
'{"foo": ["bar", "baz"]}'

iterencode(o)

주어진 객체 o를 인코딩하고, 준비될 때마다 각 문자열 표현을 산출(yield)합니다. 예를 들면:

for chunk in json.JSONEncoder().iterencode(bigobject):
    mysocket.write(chunk)

예외

exception json.JSONDecodeError(msg, doc, pos)

다음 추가 어트리뷰트가 있는 ValueError의 서브 클래스:

msg

형식 없는 에러 메시지.

doc

구문 분석 중인 JSON 문서.

pos

구문 분석에 실패한 위치의 시작 부분을 나타내는 doc의 인덱스.

lineno

pos에 해당하는 줄.

colno

pos에 해당하는 열.

Added in version 3.5.

표준 준수와 상호 운용성

The JSON format is specified by RFC 7159 [https://datatracker.ietf.org/doc/html/rfc7159.html] and by ECMA-404 [https://ecma-international.org/publications-and-standards/standards/ecma-404/]. This section details this module’s level of compliance with the RFC. For simplicity, JSONEncoder and JSONDecoder subclasses, and parameters other than those explicitly mentioned, are not considered.

유효한 JavaScript이지만 유효한 JSON이 아닌 확장을 구현함으로써, 이 모듈은 엄격한 방식으로 RFC를 준수하지는 않습니다. 특히:

무한대와 NaN 숫자 값이 받아들여지고 출력됩니다;

오브젝트 내에서 반복되는 이름이 허용되고, 마지막 이름-값 쌍의 값만 사용됩니다.

RFC가 RFC를 준수하는 구문 분석기가 RFC를 준수하지 않는 입력 텍스트를 받아들이도록 허용하기 때문에, 이 모듈의 역 직렬화기는 기본 설정에서 기술적으로 RFC를 준수합니다.

문자 인코딩

RFC는 UTF-8, UTF-16 또는 UTF-32를 사용하여 JSON을 표현할 것을 요구하고, 최대 상호 운용성을 위해 권장되는 기본값은 UTF-8입니다.

RFC에 의해 요구되는 것은 아니지만 허용되기 때문에, 이 모듈의 직렬화기는 기본적으로 ensure_ascii=True를 설정하므로, 결과 문자열에 ASCII 문자만 포함되도록 출력을 이스케이핑 합니다.

ensure_ascii 매개 변수 외에도, 이 모듈은 파이썬 객체와 유니코드 문자열 사이의 변환으로 엄격하게 정의되어 있으므로, 문자 인코딩 문제를 직접 다루지 않습니다.

RFC는 JSON 텍스트의 시작 부분에 바이트 순서 표시(BOM)를 추가하는 것을 금지하고 있으며, 이 모듈의 직렬화기는 BOM을 출력에 추가하지 않습니다. RFC는 JSON 역 직렬화기가 입력에서 초기 BOM을 무시하는 것을 허용하지만 요구하지는 않습니다. 이 모듈의 역 직렬화기는 초기 BOM이 있을 때 ValueError를 발생시킵니다.

RFC는 유효한 유니코드 문자에 해당하지 않는 바이트 시퀀스(예를 들어, 쌍을 이루지 않은 UTF-16 대리 코드(unpaired UTF-16 surrogates))가 포함된 JSON 문자열을 명시적으로 금지하지 않지만, 상호 운용성 문제를 일으킬 수 있다고 지적하고 있습니다. 기본적으로, 이 모듈은 이러한 시퀀스의 코드 포인트를 받아들이고 (원래 str에 있을 때) 출력합니다.

무한대와 NaN 숫자 값

RFC는 무한대나 NaN 숫자 값의 표현을 허용하지 않습니다. 그런데도, 기본적으로, 이 모듈은 유효한 JSON 숫자 리터럴 값인 것처럼 Infinity, -Infinity 및 NaN을 받아들이고 출력합니다:

>>> # Neither of these calls raises an exception, but the results are not valid JSON
>>> json.dumps(float('-inf'))
'-Infinity'
>>> json.dumps(float('nan'))
'NaN'
>>> # Same when deserializing
>>> json.loads('-Infinity')
-inf
>>> json.loads('NaN')
nan

직렬화기에서, allow_nan 매개 변수를 사용하여 이 동작을 변경할 수 있습니다. 역 직렬화기에서, parse_constant 매개 변수를 사용하여 이 동작을 변경할 수 있습니다.

오브젝트 내에서 반복된 이름

RFC는 JSON 오브젝트 내에서 이름이 고유해야 한다고 지정하지만, JSON 오브젝트 내에서 반복되는 이름을 처리하는 방법을 지정하지는 않습니다. 기본적으로, 이 모듈은 예외를 발생시키지 않습니다; 대신, 주어진 이름에 대한 마지막 이름-값 쌍을 제외한 모든 것을 무시합니다:

>>> weird_json = '{"x": 1, "x": 2, "x": 3}'
>>> json.loads(weird_json)
{'x': 3}

object_pairs_hook 매개 변수는 이 동작을 변경하는 데 사용할 수 있습니다.

오브젝트나 배열이 아닌 최상윗값

폐지된 RFC 4627 [https://datatracker.ietf.org/doc/html/rfc4627.html]에 의해 지정된 이전 버전의 JSON은 JSON 텍스트의 최상윗값이 JSON 오브젝트나 배열(파이썬 dict나 list)이어야 하고, JSON null, 불리언, 숫자 또는 문자열 값이 될 수 없다고 요구합니다. RFC 7159 [https://datatracker.ietf.org/doc/html/rfc7159.html]는 그 제한을 제거했으며, 이 모듈은 직렬화기와 역 직렬화기에서 이러한 제한을 구현하지 않으며, 그런 적도 없습니다.

이와 관계없이, 최대한의 상호 운용성을 위해, 여러분은 자발적으로 제한을 준수하기를 원할 수 있습니다.

구현 제약 사항

일부 JSON 역 직렬화기 구현은 다음과 같은 것들에 대한 제한을 설정할 수 있습니다:

받아들인 JSON 텍스트의 크기

JSON 오브젝트와 배열의 최대 중첩 수준

JSON 숫자의 범위와 정밀도

JSON 문자열의 내용과 최대 길이

이 모듈은 관련 파이썬 데이터형 자체나 파이썬 인터프리터 자체의 한계 외에는 어떤 제한도 가하지 않습니다.

JSON으로 직렬화할 때, 여러분의 JSON을 사용할 응용 프로그램에 있는 이러한 제한 사항에 주의하십시오. 특히, JSON 숫자가 IEEE 754 배정도 숫자로 역 직렬화되는 것이 일반적이고, 그래서 그 표현의 범위와 정밀도 제한이 적용됩니다. 이것은 매우 큰 규모의 파이썬 int 값을 직렬화하거나, decimal.Decimal과 같은 “색다른” 숫자 형의 인스턴스를 직렬화할 때 특히 중요합니다.

Command-line interface

소스 코드: Lib/json/tool.py [https://github.com/python/cpython/tree/main/Lib/json/tool.py]

The json module can be invoked as a script via python -m json to validate and pretty-print JSON objects. The json.tool submodule implements this interface.

If the optional infile and outfile arguments are not specified, sys.stdin and sys.stdout will be used respectively:

$ echo '{"json": "obj"}' | python -m json
{
    "json": "obj"
}
$ echo '{1.2:3.4}' | python -m json
Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

버전 3.5에서 변경: 출력은 이제 입력과 같은 순서입니다. 딕셔너리의 출력을 키에 대해 알파벳 순으로 정렬하려면 --sort-keys 옵션을 사용하십시오.

버전 3.14에서 변경: The json module may now be directly executed as python -m json. For backwards compatibility, invoking the CLI as python -m json.tool remains supported.

Command-line options

infile

유효성을 검사하거나 예쁘게 인쇄할 JSON 파일:

$ python -m json mp_films.json
[
    {
        "title": "And Now for Something Completely Different",
        "year": 1971
    },
    {
        "title": "Monty Python and the Holy Grail",
        "year": 1975
    }
]

If infile is not specified, read from sys.stdin.

outfile

Write the output of the infile to the given outfile. Otherwise, write it to sys.stdout.

--sort-keys

딕셔너리의 출력을 키에 대해 알파벳 순으로 정렬합니다.

Added in version 3.5.

--no-ensure-ascii

비 ASCII 문자의 이스케이프를 비활성화합니다. 자세한 내용은 json.dumps()를 참조하십시오.

Added in version 3.9.

--json-lines

모든 입력 행을 별도의 JSON 객체로 구문 분석합니다.

Added in version 3.8.

--indent, --tab, --no-indent, --compact

공백 제어를 위한 상호 배타적 옵션.

Added in version 3.9.

-h, --help

도움말 메시지를 표시합니다.

각주

[1]

the errata for RFC 7159 [https://www.rfc-editor.org/errata_search.php?rfc=7159]에서 언급했듯이, JSON은 문자열에 U+2028(LINE SEPARATOR)과 U+2029(PARAGRAPH SEPARATOR) 문자를 허용하지만, JavaScript(ECMAScript Edition 5.1 기준)는 허용하지 않습니다.

mailbox — Manipulate mailboxes in various formats

소스 코드: Lib/mailbox.py [https://github.com/python/cpython/tree/main/Lib/mailbox.py]

This module defines two classes, Mailbox and Message, for accessing and manipulating on-disk mailboxes and the messages they contain. Mailbox offers a dictionary-like mapping from keys to messages. Message extends the email.message module’s Message class with format-specific state and behavior. Supported mailbox formats are Maildir, mbox, MH, Babyl, and MMDF.

더 보기

모듈 email

메시지를 표현하고 조작합니다.

Mailbox objects

class mailbox.Mailbox

검사하고 수정할 수 있는 사서함.

The Mailbox class defines an interface and is not intended to be instantiated. Instead, format-specific subclasses should inherit from Mailbox and your code should instantiate a particular subclass.

The Mailbox interface is dictionary-like, with small keys corresponding to messages. Keys are issued by the Mailbox instance with which they will be used and are only meaningful to that Mailbox instance. A key continues to identify a message even if the corresponding message is modified, such as by replacing it with another message.

Messages may be added to a Mailbox instance using the set-like method add() and removed using a del statement or the set-like methods remove() and discard().

Mailbox interface semantics differ from dictionary semantics in some noteworthy ways. Each time a message is requested, a new representation (typically a Message instance) is generated based upon the current state of the mailbox. Similarly, when a message is added to a Mailbox instance, the provided message representation’s contents are copied. In neither case is a reference to the message representation kept by the Mailbox instance.

The default Mailbox iterator iterates over message representations, not keys as the default dictionary iterator does. Moreover, modification of a mailbox during iteration is safe and well-defined. Messages added to the mailbox after an iterator is created will not be seen by the iterator. Messages removed from the mailbox before the iterator yields them will be silently skipped, though using a key from an iterator may result in a KeyError exception if the corresponding message is subsequently removed.

경고

Be very cautious when modifying mailboxes that might be simultaneously changed by some other process. The safest mailbox format to use for such tasks is Maildir; try to avoid using single-file formats such as mbox for concurrent writing. If you’re modifying a mailbox, you must lock it by calling the lock() and unlock() methods before reading any messages in the file or making any changes by adding or deleting a message. Failing to lock the mailbox runs the risk of losing messages or corrupting the entire mailbox.

Mailbox instances have the following methods:

add(message)

사서함에 message를 추가하고 할당된 키를 반환합니다.

매개 변수 message는 Message 인스턴스, email.message.Message 인스턴스, 문자열, 바이트 문자열 또는 파일류 객체(바이너리 모드로 열어야 합니다)일 수 있습니다. message가 적절한 형식별 Message 서브 클래스의 인스턴스이면 (예를 들어, 이것이 mbox 인스턴스일 때 mboxMessage 인스턴스이면), 형식별 정보가 사용됩니다. 그렇지 않으면, 형식별 정보에 대한 적절한 기본값이 사용됩니다.

버전 3.2에서 변경: 바이너리 입력에 대한 지원이 추가되었습니다.

remove(key)

__delitem__(key)

discard(key)

사서함에서 key에 해당하는 메시지를 삭제합니다.

그러한 메시지가 없으면, 메서드가 remove()나 __delitem__()으로 호출되면 KeyError 예외가 발생하지만, discard()로 호출되면 예외가 발생하지 않습니다. 하부 사서함 형식이 다른 프로세스에 의한 동시 수정을 지원하면 discard()의 동작을 선호할 수 있습니다.

__setitem__(key, message)

key에 해당하는 메시지를 message로 바꿉니다. key에 해당하는 메시지가 없으면 KeyError 예외를 발생시킵니다.

add()와 마찬가지로, message 매개 변수는 Message 인스턴스, email.message.Message 인스턴스, 문자열, 바이트 문자열 또는 파일류 객체(바이너리 모드로 열어야 합니다)일 수 있습니다. message가 적절한 형식별 Message 서브 클래스의 인스턴스이면 (예를 들어, 이것이 mbox 인스턴스일 때 mboxMessage 인스턴스이면), 형식별 정보가 사용됩니다. 그렇지 않으면, 현재 key에 해당하는 메시지의 형식별 정보가 변경되지 않습니다.

iterkeys()

Return an iterator over all keys

keys()

The same as iterkeys(), except that a list is returned rather than an iterator

itervalues()

__iter__()

Return an iterator over representations of all messages. The messages are represented as instances of the appropriate format-specific Message subclass unless a custom message factory was specified when the Mailbox instance was initialized.

참고

__iter__()의 동작은 키를 이터레이트 하는 딕셔너리의 동작과 다릅니다.

values()

The same as itervalues(), except that a list is returned rather than an iterator

iteritems()

Return an iterator over (key, message) pairs, where key is a key and message is a message representation. The messages are represented as instances of the appropriate format-specific Message subclass unless a custom message factory was specified when the Mailbox instance was initialized.

items()

The same as iteritems(), except that a list of pairs is returned rather than an iterator of pairs.

get(key, default=None)

__getitem__(key)

Return a representation of the message corresponding to key. If no such message exists, default is returned if the method was called as get() and a KeyError exception is raised if the method was called as __getitem__(). The message is represented as an instance of the appropriate format-specific Message subclass unless a custom message factory was specified when the Mailbox instance was initialized.

get_message(key)

key에 해당하는 메시지의 표현을 적절한 형식별 Message 서브 클래스의 인스턴스로 반환하거나, 그러한 메시지가 없으면 KeyError 예외를 발생시킵니다.

get_bytes(key)

key에 해당하는 메시지의 바이트 표현을 반환하거나, 그러한 메시지가 없으면 KeyError 예외를 발생시킵니다.

Added in version 3.2.

get_string(key)

key에 해당하는 메시지의 문자열 표현을 반환하거나 그러한 메시지가 없으면 KeyError 예외를 발생시킵니다. 메시지는 email.message.Message를 통해 처리되어 7비트(7bit clean) 표현으로 변환됩니다.

get_file(key)

Return a file-like representation of the message corresponding to key, or raise a KeyError exception if no such message exists. The file-like object behaves as if open in binary mode. This file should be closed once it is no longer needed.

버전 3.2에서 변경: The file object really is a binary file; previously it was incorrectly returned in text mode. Also, the file-like object now supports the context manager protocol: you can use a with statement to automatically close it.

참고

Unlike other representations of messages, file-like representations are not necessarily independent of the Mailbox instance that created them or of the underlying mailbox. More specific documentation is provided by each subclass.

__contains__(key)

key가 메시지에 해당하면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

__len__()

사서함에 있는 메시지 수를 반환합니다.

clear()

사서함에서 모든 메시지를 삭제합니다.

pop(key, default=None)

Return a representation of the message corresponding to key and delete the message. If no such message exists, return default. The message is represented as an instance of the appropriate format-specific Message subclass unless a custom message factory was specified when the Mailbox instance was initialized.

popitem()

Return an arbitrary (key, message) pair, where key is a key and message is a message representation, and delete the corresponding message. If the mailbox is empty, raise a KeyError exception. The message is represented as an instance of the appropriate format-specific Message subclass unless a custom message factory was specified when the Mailbox instance was initialized.

update(arg)

Parameter arg should be a key-to-message mapping or an iterable of (key, message) pairs. Updates the mailbox so that, for each given key and message, the message corresponding to key is set to message as if by using __setitem__(). As with __setitem__(), each key must already correspond to a message in the mailbox or else a KeyError exception will be raised, so in general it is incorrect for arg to be a Mailbox instance.

참고

딕셔너리와 달리 키워드 인자는 지원되지 않습니다.

flush()

Write any pending changes to the filesystem. For some Mailbox subclasses, changes are always written immediately and flush() does nothing, but you should still make a habit of calling this method.

lock()

다른 프로세스가 수정하지 않아야 한다는 것을 알 수 있도록 사서함에 대한 배타적 권고 잠금(exclusive advisory lock)을 획득합니다. 잠금을 사용할 수 없으면 ExternalClashError 가 발생합니다. 사용되는 특정 잠금 메커니즘은 사서함 형식에 따라 다릅니다. 내용을 수정하기 전에 사서함을 항상 잠가야 합니다.

unlock()

사서함의 잠금을 해제합니다 (있다면).

close()

Flush the mailbox, unlock it if necessary, and close any open files. For some Mailbox subclasses, this method does nothing.

Maildir objects

class mailbox.Maildir(dirname, factory=None, create=True)

Maildir 형식의 사서함에 대한 Mailbox의 서브 클래스. 매개 변수 factory는 파일류 메시지 표현(바이너리 모드에서 열린 것처럼 동작합니다)을 받아들이고 사용자 정의 표현을 반환하는 콜러블 객체입니다. factory가 None이면, MaildirMessage 가 기본 메시지 표현으로 사용됩니다. create가 True이면, 사서함이 없으면 만들어집니다.

create가 True이고 dirname 경로가 존재하면, 디렉터리 레이아웃을 확인하지 않고 기존 maildir로 처리됩니다.

역사적인 이유로 path가 아니라 dirname이라고 이름 붙였습니다.

Maildir은 qmail 메일 전송 에이전트를 위해 고안된 디렉터리 기반 사서함 형식이며 현재 다른 프로그램에서 널리 지원됩니다. Maildir 사서함의 메시지는 공통 디렉터리 구조 내에서 별도의 파일에 저장됩니다. 이 설계를 사용하면 데이터 손상 없이 여러 관련 없는 프로그램에서 Maildir 사서함에 액세스하고 수정할 수 있어서 파일 잠금이 필요하지 않습니다.

Maildir 사서함에는 세 개의 하위 디렉터리가 있습니다, 이름하여 tmp, new 및 cur. 메시지는 일시적으로 tmp 하위 디렉터리에 만들어진 다음 new 하위 디렉터리로 이동하여 전달을 완료합니다. 메일 사용자 에이전트는 이후에 메시지를 cur 하위 디렉터리로 이동하고 파일 이름에 추가된 특수 “info” 섹션에 메시지 상태에 대한 정보를 저장할 수 있습니다.

Folders of the style introduced by the Courier mail transfer agent are also supported. Any subdirectory of the main mailbox is considered a folder if '.' is the first character in its name. Folder names are represented by Maildir without the leading '.'. Each folder is itself a Maildir mailbox but should not contain other folders. Instead, a logical nesting is indicated using '.' to delimit levels, e.g., “Archived.2005.07”.

colon

Maildir 명세에서는 특정 메시지 파일 이름에 콜론(':')을 사용하도록 요구합니다. 그러나 일부 운영 체제에서는 파일 이름에 이 문자를 허용하지 않습니다. 이러한 운영 체제에서 Maildir과 유사한 형식을 사용하려면, 대신 사용할 다른 문자를 지정해야 합니다. 느낌표('!')는 인기 있는 선택입니다. 예를 들면:

import mailbox
mailbox.Maildir.colon = '!'

The colon attribute may also be set on a per-instance basis.

버전 3.13에서 변경: Maildir now ignores files with a leading dot.

Maildir instances have all of the methods of Mailbox in addition to the following:

list_folders()

모든 폴더의 이름 리스트를 반환합니다.

get_folder(folder)

Return a Maildir instance representing the folder whose name is folder. A NoSuchMailboxError exception is raised if the folder does not exist.

add_folder(folder)

Create a folder whose name is folder and return a Maildir instance representing it.

remove_folder(folder)

이름이 folder인 폴더를 삭제합니다. 폴더에 메시지가 포함되었으면, NotEmptyError 예외가 발생하고 폴더가 삭제되지 않습니다.

clean()

지난 36시간 동안 액세스하지 않은 사서함에서 임시 파일을 삭제합니다. Maildir 명세는 메일을 읽는 프로그램이 이 작업을 가끔 수행해야 한다고 말합니다.

get_flags(key)

Return as a string the flags that are set on the message corresponding to key. This is the same as get_message(key).get_flags() but much faster, because it does not open the message file. Use this method when iterating over the keys to determine which messages are interesting to get.

If you do have a MaildirMessage object, use its get_flags() method instead, because changes made by the message’s set_flags(), add_flag() and remove_flag() methods are not reflected here until the mailbox’s __setitem__() method is called.

Added in version 3.13.

set_flags(key, flags)

On the message corresponding to key, set the flags specified by flags and unset all others. Calling some_mailbox.set_flags(key, flags) is similar to

one_message = some_mailbox.get_message(key)
one_message.set_flags(flags)
some_mailbox[key] = one_message

but faster, because it does not open the message file.

If you do have a MaildirMessage object, use its set_flags() method instead, because changes made with this mailbox method will not be visible to the message object’s method, get_flags().

Added in version 3.13.

add_flag(key, flag)

On the message corresponding to key, set the flags specified by flag without changing other flags. To add more than one flag at a time, flag may be a string of more than one character.

Considerations for using this method versus the message object’s add_flag() method are similar to those for set_flags(); see the discussion there.

Added in version 3.13.

remove_flag(key, flag)

On the message corresponding to key, unset the flags specified by flag without changing other flags. To remove more than one flag at a time, flag may be a string of more than one character.

Considerations for using this method versus the message object’s remove_flag() method are similar to those for set_flags(); see the discussion there.

Added in version 3.13.

get_info(key)

Return a string containing the info for the message corresponding to key. This is the same as get_message(key).get_info() but much faster, because it does not open the message file. Use this method when iterating over the keys to determine which messages are interesting to get.

If you do have a MaildirMessage object, use its get_info() method instead, because changes made by the message’s set_info() method are not reflected here until the mailbox’s __setitem__() method is called.

Added in version 3.13.

set_info(key, info)

Set the info of the message corresponding to key to info. Calling some_mailbox.set_info(key, flags) is similar to

one_message = some_mailbox.get_message(key)
one_message.set_info(info)
some_mailbox[key] = one_message

but faster, because it does not open the message file.

If you do have a MaildirMessage object, use its set_info() method instead, because changes made with this mailbox method will not be visible to the message object’s method, get_info().

Added in version 3.13.

Some Mailbox methods implemented by Maildir deserve special remarks:

add(message)

__setitem__(key, message)

update(arg)

경고

이 메서드들은 현재 프로세스 ID를 기반으로 고유한 파일 이름을 생성합니다. 다중 스레드를 사용할 때, 이러한 메서드를 사용하여 같은 사서함을 동시에 조작하지 않도록 스레드를 조정하지 않으면 감지되지 않은 이름 충돌이 발생하여 사서함이 손상될 수 있습니다.

flush()

Maildir 사서함에 대한 모든 변경 사항은 즉시 적용되므로, 이 메서드는 아무 작업도 수행하지 않습니다.

lock()

unlock()

Maildir 사서함은 잠금을 지원(또는 필요로)하지 않아서, 이 메서드들은 아무 작업도 수행하지 않습니다.

close()

Maildir instances do not keep any open files and the underlying mailboxes do not support locking, so this method does nothing.

get_file(key)

호스트 플랫폼에 따라, 반환된 파일이 열려있는 동안 하부 메시지를 수정하거나 제거하지 못할 수 있습니다.

더 보기

maildir man page from Courier [https://www.courier-mta.org/maildir.html]

형식의 명세. 지원 폴더에 대한 공통 확장을 설명합니다.

Using maildir format [https://cr.yp.to/proto/maildir.html]

발명가의 Maildir에 대한 노트. 개정된 이름 생성 체계와 “info” 의미론에 대한 세부 정보를 포함합니다.

mbox objects

class mailbox.mbox(path, factory=None, create=True)

mbox 형식의 사서함에 대한 Mailbox의 서브 클래스. 매개 변수 factory는 파일류 메시지 표현(바이너리 모드에서 열린 것처럼 동작합니다)을 받아들이고 사용자 정의 표현을 반환하는 콜러블 객체입니다. factory가 None이면, mboxMessage가 기본 메시지 표현으로 사용됩니다. create가 True이면, 사서함이 없으면 만들어집니다.

mbox 형식은 유닉스 시스템에서 메일을 저장하기 위한 고전적인 형식입니다. mbox 사서함의 모든 메시지는 처음 5개의 문자가 “From “인 줄로 표시되는 각 메시지의 시작 부분과 함께 단일 파일에 저장됩니다.

Several variations of the mbox format exist to address perceived shortcomings in the original. In the interest of compatibility, mbox implements the original format, which is sometimes referred to as mboxo. This means that the Content-Length header, if present, is ignored and that any occurrences of “From “ at the beginning of a line in a message body are transformed to “>From “ when storing the message, although occurrences of “>From “ are not transformed to “From “ when reading the message.

Some Mailbox methods implemented by mbox deserve special remarks:

get_file(key)

Using the file after calling flush() or close() on the mbox instance may yield unpredictable results or raise an exception.

lock()

unlock()

Three locking mechanisms are used—dot locking and, if available, the flock() and lockf() system calls.

더 보기

tin의 mbox 매뉴얼 페이지 [http://www.tin.org/bin/man.cgi?section=5&topic=mbox]

형식의 명세, 잠금에 대한 세부 정보가 있습니다.

유닉스에서 Netscape Mail 구성하기: 왜 Content-Length 형식이 나쁜가 [https://www.jwz.org/doc/content-length.html]

변형이 아닌 원래 mbox 형식을 사용하는 것에 대한 논의.

“mbox”는 서로 호환되지 않는 여러 사서함 형식의 집합입니다 [https://www.loc.gov/preservation/digital/formats/fdd/fdd000383.shtml]

mbox 변형의 역사.

MH objects

class mailbox.MH(path, factory=None, create=True)

MH 형식의 사서함에 대한 Mailbox의 서브 클래스. 매개 변수 factory는 파일류 메시지 표현(바이너리 모드에서 열린 것처럼 동작합니다)을 받아들이고 사용자 정의 표현을 반환하는 콜러블 객체입니다. factory가 None이면, MHMessage가 기본 메시지 표현으로 사용됩니다. create가 True이면, 사서함이 없으면 만들어집니다.

MH는 메일 사용자 에이전트인 MH 메시지 처리 시스템(MH Message Handling System)을 위해 개발된 디렉터리 기반 사서함 형식입니다. MH 사서함의 각 메시지는 각자의 파일에 있습니다. MH 사서함에는 메시지 외에 다른 MH 사서함(폴더(folders)라고 합니다)이 포함될 수 있습니다. 폴더는 무제한 중첩될 수 있습니다. MH 사서함은 또한 메시지를 서브 폴더로 이동하지 않고 논리적으로 그룹화하는 데 사용되는 명명된 목록인 시퀀스(sequences)를 지원합니다. 시퀀스는 각 폴더의 .mh_sequences라는 파일에 정의됩니다.

The MH class manipulates MH mailboxes, but it does not attempt to emulate all of mh’s behaviors. In particular, it does not modify and is not affected by the context or .mh_profile files that are used by mh to store its state and configuration.

MH instances have all of the methods of Mailbox in addition to the following:

버전 3.13에서 변경: Supported folders that don’t contain a .mh_sequences file.

list_folders()

모든 폴더의 이름 리스트를 반환합니다.

get_folder(folder)

Return an MH instance representing the folder whose name is folder. A NoSuchMailboxError exception is raised if the folder does not exist.

add_folder(folder)

Create a folder whose name is folder and return an MH instance representing it.

remove_folder(folder)

이름이 folder인 폴더를 삭제합니다. 폴더에 메시지가 포함되었으면, NotEmptyError 예외가 발생하고 폴더가 삭제되지 않습니다.

get_sequences()

키 리스트에 매핑된 시퀀스 이름의 딕셔너리를 반환합니다. 시퀀스가 없으면, 빈 딕셔너리가 반환됩니다.

set_sequences(sequences)

get_sequences()에서 반환하는 것과 같이, 키 리스트에 매핑된 이름의 딕셔너리인, sequences를 기반으로 사서함에 존재하는 시퀀스를 다시 정의합니다.

pack()

번호 매기기의 간격을 없애기 위해 필요에 따라 사서함의 메시지 이름을 변경합니다. 시퀀스 리스트의 항목이 그에 따라 갱신됩니다.

참고

이미 발급된 키는 이 작업에 의해 무효가 되며 이후에 사용해서는 안 됩니다.

Some Mailbox methods implemented by MH deserve special remarks:

remove(key)

__delitem__(key)

discard(key)

이 메서드들은 메시지를 즉시 삭제합니다. 이름 앞에 쉼표를 추가하여 메시지를 삭제하도록 표시하는 MH 규칙은 사용되지 않습니다.

lock()

unlock()

Three locking mechanisms are used—dot locking and, if available, the flock() and lockf() system calls. For MH mailboxes, locking the mailbox means locking the .mh_sequences file and, only for the duration of any operations that affect them, locking individual message files.

get_file(key)

호스트 플랫폼에 따라, 반환된 파일이 열려있는 동안 하부 메시지를 제거하지 못할 수도 있습니다.

flush()

MH 사서함에 대한 모든 변경 사항이 즉시 적용되므로, 이 메서드는 아무 작업도 수행하지 않습니다.

close()

MH instances do not keep any open files, so this method is equivalent to unlock().

더 보기

nmh - Message Handling System [https://www.nongnu.org/nmh/]

nmh의 홈페이지, 원래 mh의 갱신된 버전.

MH & nmh: 사용자와 프로그래머를 위한 이메일 [https://rand-mh.sourceforge.io/book/]

mh와 nmh에 대한 GPL 라이선스 책, 사서함 형식에 대한 정보가 있습니다.

Babyl objects

class mailbox.Babyl(path, factory=None, create=True)

Babyl 형식의 사서함에 대한 Mailbox의 서브 클래스. 매개 변수 factory는 파일류 메시지 표현(바이너리 모드에서 열린 것처럼 동작합니다)을 받아들이고 사용자 정의 표현을 반환하는 콜러블 객체입니다. factory가 None이면, BabylMessage가 기본 메시지 표현으로 사용됩니다. create가 True이면, 사서함이 없으면 만들어집니다.

Babyl은 Emacs에 포함된 Rmail 메일 사용자 에이전트에서 사용하는 단일 파일 사서함 형식입니다. 메시지의 시작 부분은 Control-Underscore('\037')와 Control-L('\014') 두 문자가 포함된 줄로 표시됩니다. 메시지의 끝은 다음 메시지의 시작이나, 마지막 메시지의 경우 Control-Underscore('\037') 문자가 포함된 줄로 표시됩니다.

Babyl 사서함의 메시지는 두 집합의 헤더가 있습니다, 원래 헤더와 소위 가시적(visible) 헤더가 있습니다. 가시적 헤더는 일반적으로 더 매력적으로 다시 포맷되거나 요약된 원래 헤더의 부분 집합입니다. Babyl 사서함의 각 메시지에는 레이블(labels) 리스트, 또는 메시지에 대한 추가 정보를 기록하는 짧은 문자열이 있으며, 사서함에 있는 모든 사용자 정의 레이블 목록은 Babyl 옵션 섹션에 보관됩니다.

Babyl instances have all of the methods of Mailbox in addition to the following:

get_labels()

사서함에 사용된 모든 사용자 정의 레이블의 이름 리스트를 반환합니다.

참고

Babyl 옵션 섹션의 레이블 목록을 참조하지 않고 사서함에 있는 레이블을 확인하기 위해 실제 메시지를 검사하지만, 사서함이 수정될 때마다 Babyl 섹션이 갱신됩니다.

Some Mailbox methods implemented by Babyl deserve special remarks:

get_file(key)

Babyl 사서함에서, 메시지 헤더는 메시지 본문과 연속적으로 저장되지 않습니다. 파일류 표현을 생성하기 위해, 헤더와 본문이 파일과 동일한 API를 가진 io.BytesIO 인스턴스에 함께 복사됩니다. 결과적으로, 파일류 객체는 하부 사서함과는 진짜로 독립적이지만 문자열 표현보다 메모리를 절약하지 않습니다.

lock()

unlock()

Three locking mechanisms are used—dot locking and, if available, the flock() and lockf() system calls.

더 보기

Format of Version 5 Babyl Files [https://quimby.gnus.org/notes/BABYL]

Babyl 형식의 명세.

Rmail로 메일 읽기 [https://www.gnu.org/software/emacs/manual/html_node/emacs/Rmail.html]

Rmail 매뉴얼, Babyl 의미론에 대한 정보가 있습니다.

MMDF objects

class mailbox.MMDF(path, factory=None, create=True)

MMDF 형식의 사서함에 대한 Mailbox의 서브 클래스. 매개 변수 factory는 파일류 메시지 표현(바이너리 모드에서 열린 것처럼 동작합니다)을 받아들이고 사용자 정의 표현을 반환하는 콜러블 객체입니다. factory가 None이면, MMDFMessage가 기본 메시지 표현으로 사용됩니다. create가 True이면, 사서함이 없으면 만들어집니다.

MMDF는 메일 전송 에이전트인 Multichannel Memorandum Distribution Facility를 위해 개발된 단일 파일 사서함 형식입니다. 각 메시지는 mbox 메시지와 같은 형식이지만 4개의 Control-A ('\001') 문자를 포함하는 줄로 앞뒤로 둘러쌉니다. mbox 형식과 마찬가지로, 각 메시지의 시작 부분은 처음 5개의 문자가 “From “인 줄로 표시되지만, 메시지를 저장할 때 추가로 등장하는 “From “을 “>From “으로 변환하지 않습니다, 메시지를 구분하는 추가적인 줄로 인해 후속 메시지의 시작으로 착각할 우려가 없기 때문입니다.

Some Mailbox methods implemented by MMDF deserve special remarks:

get_file(key)

Using the file after calling flush() or close() on the MMDF instance may yield unpredictable results or raise an exception.

lock()

unlock()

Three locking mechanisms are used—dot locking and, if available, the flock() and lockf() system calls.

더 보기

tin의 mmdf 매뉴얼 페이지 [http://www.tin.org/bin/man.cgi?section=5&topic=mmdf]

뉴스 리더인 tin의 설명서에 있는 MMDF 형식의 명세.

MMDF [https://en.wikipedia.org/wiki/MMDF]

Multichannel Memorandum Distribution Facility를 설명하는 위키피디아 기사.

Message objects

class mailbox.Message(message=None)

A subclass of the email.message module’s Message. Subclasses of mailbox.Message add mailbox-format-specific state and behavior.

If message is omitted, the new instance is created in a default, empty state. If message is an email.message.Message instance, its contents are copied; furthermore, any format-specific information is converted insofar as possible if message is a Message instance. If message is a string, a byte string, or a file, it should contain an RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html]-compliant message, which is read and parsed. Files should be open in binary mode, but text mode files are accepted for backward compatibility.

서브 클래스에서 제공하는 형식별 상태와 동작은 다양하지만, 일반적으로 지원되는 특정 사서함에만 고유하지는 않은 속성입니다 (아마도 속성은 특정 사서함 형식에 고유합니다). 예를 들어, 단일 파일 사서함 형식에 대한 파일 오프셋과 디렉터리 기반 사서함 형식에 대한 파일 이름은 유지되지 않는데, 원래 사서함에만 적용되기 때문입니다. 그러나 사용자가 메시지를 읽었는지나 중요하다고 표시되었는지와 같은 상태는 메시지 자체에 적용되므로 유지됩니다.

There is no requirement that Message instances be used to represent messages retrieved using Mailbox instances. In some situations, the time and memory required to generate Message representations might not be acceptable. For such situations, Mailbox instances also offer string and file-like representations, and a custom message factory may be specified when a Mailbox instance is initialized.

MaildirMessage objects

class mailbox.MaildirMessage(message=None)

Maildir 특정 동작을 갖는 메시지. 매개 변수 message는 Message 생성자와 같은 의미입니다.

일반적으로, 메일 사용자 에이전트 응용 프로그램은 사용자가 사서함을 처음 열고 닫은 후 new 하위 디렉터리의 모든 메시지를 cur 하위 디렉터리로 이동하여, 메시지가 실제로 읽혔는지에 관계없이 오래되었음을 기록합니다. cur의 각 메시지에는 상태에 대한 정보를 저장하기 위해 파일 이름에 추가된 “info” 섹션이 있습니다. (일부 메일 리더는 new의 메시지에 “info” 섹션을 추가할 수도 있습니다.) “info” 섹션은 두 가지 형식 중 하나를 취할 수 있습니다: “2,”와 그 뒤로 표준화된 플래그 목록이 오거나 (예를 들어, “2,FR”), “1,”과 그 뒤로 소위 실험적 정보를 포함할 수 있습니다. Maildir 메시지의 표준 플래그는 다음과 같습니다:

플래그

의미

설명

D

초안

작성 중

F

깃발 표시

중요하다고 표시됨

P

전달됨

전달, 재전송 또는 반송됨

R

답장함

답장함

S

보았음

읽었음

T

휴지통

후에 삭제하기 위해 표시함

MaildirMessage instances offer the following methods:

get_subdir()

“new”(메시지가 new 하위 디렉터리에 저장되어야 하면)나 “cur”(메시지가 cur 하위 디렉터리에 저장되어야 하면)를 반환합니다.

참고

A message is typically moved from new to cur after its mailbox has been accessed, whether or not the message has been read. A message msg has been read if "S" in msg.get_flags() is True.

set_subdir(subdir)

메시지를 저장할 하위 디렉터리를 설정합니다. 매개 변수 subdir은 “new”나 “cur”여야 합니다.

get_flags()

현재 설정된 플래그를 지정하는 문자열을 반환합니다. 메시지가 표준 Maildir 형식을 준수하면, 결과는 'D', 'F', 'P', 'R', 'S' 및 'T'의 각 항목이 알파벳 순서로 0이나 1개 등장하는 이어붙이기입니다. 플래그가 설정되지 않았거나 “info”에 실험적 의미가 포함되어 있으면 빈 문자열이 반환됩니다.

set_flags(flags)

flags로 지정된 플래그를 설정하고 다른 모든 플래그를 설정 해제합니다.

add_flag(flag)

다른 플래그를 변경하지 않고 flag로 지정된 플래그를 설정합니다. 한 번에 둘 이상의 플래그를 추가하기 위해, flag가 둘 이상의 문자로 구성된 문자열일 수 있습니다. 플래그 대신 실험적 정보를 포함하는지와 관계없이 현재 “info”를 덮어씁니다.

remove_flag(flag)

다른 플래그를 변경하지 않고 flag에 의해 지정된 플래그를 설정 해제합니다. 한 번에 둘 이상의 플래그를 제거하기 위해, flag는 둘 이상의 문자로 구성된 문자열일 수 있습니다. “info”에 플래그 대신 실험적 정보가 포함되어 있으면, 현재 “info”가 수정되지 않습니다.

get_date()

메시지의 배달 날짜를 에포크(Epoch) 이후 초를 나타내는 부동 소수점 숫자로 반환합니다.

set_date(date)

메시지의 배달 날짜를 date로 설정합니다. 이는 에포크(Epoch) 이후 초를 나타내는 부동 소수점 숫자입니다.

get_info()

메시지에 대한 “info”를 포함하는 문자열을 반환합니다. 이것은 실험적인 (즉, 플래그 목록이 아닌) “info”를 액세스하고 수정하는 데 유용합니다.

set_info(info)

“info”를 문자열이어야 하는 info로 설정합니다.

When a MaildirMessage instance is created based upon an mboxMessage or MMDFMessage instance, the Status and X-Status headers are omitted and the following conversions take place:

결과 상태

mboxMessage나 MMDFMessage 상태

“cur” 하위 디렉터리

O 플래그

F 플래그

F 플래그

R 플래그

A 플래그

S 플래그

R 플래그

T 플래그

D 플래그

When a MaildirMessage instance is created based upon an MHMessage instance, the following conversions take place:

결과 상태

MHMessage 상태

“cur” 하위 디렉터리

“unseen” 시퀀스

“cur” 하위 디렉터리와 S 플래그

“unseen” 시퀀스 없음

F 플래그

“flagged” 시퀀스

R 플래그

“replied” 시퀀스

When a MaildirMessage instance is created based upon a BabylMessage instance, the following conversions take place:

결과 상태

BabylMessage 상태

“cur” 하위 디렉터리

“unseen” 레이블

“cur” 하위 디렉터리와 S 플래그

“unseen” 레이블 없음

P 플래그

“forwarded”나 “resent” 레이블

R 플래그

“answered” 레이블

T 플래그

“deleted” 레이블

mboxMessage objects

class mailbox.mboxMessage(message=None)

mbox 특정 동작을 갖는 메시지. 매개 변수 message는 Message 생성자와 같은 의미입니다.

mbox 사서함의 메시지는 단일 파일에 함께 저장됩니다. 보낸 사람의 봉투 주소(envelope address)와 배달 시간은 일반적으로 메시지의 시작을 나타내는 데 사용되는 “From “으로 시작하는 줄에 저장되지만, mbox 구현 간에 이 데이터의 정확한 형식에는 상당한 차이가 있습니다. 읽었는지나 중요하다고 표시되었는지와 같은 메시지 상태를 나타내는 플래그는 일반적으로 Status와 X-Status 헤더에 저장됩니다.

mbox 메시지의 전통적인 플래그는 다음과 같습니다:

플래그

의미

설명

R

읽었음

읽었음

O

오래되었음

전에 MUA에서 감지됨

D

삭제됨

후에 삭제하기 위해 표시함

F

깃발 표시

중요하다고 표시됨

A

답변함

답장함

“R”과 “O” 플래그는 Status 헤더에 저장되고, “D”, “F” 및 “A” 플래그는 X-Status 헤더에 저장됩니다. 플래그와 헤더는 일반적으로 언급된 순서대로 나타납니다.

mboxMessage instances offer the following methods:

get_from()

mbox 사서함에서 메시지의 시작을 표시하는 “From “ 줄을 나타내는 문자열을 반환합니다. 선행 “From “과 후행 줄넘김은 제외됩니다.

set_from(from_, time_=None)

Set the “From “ line to from_, which should be specified without a leading “From “ or trailing newline. For convenience, time_ may be specified and will be formatted appropriately and appended to from_. If time_ is specified, it should be a time.struct_time instance, a tuple suitable for passing to time.strftime(), or True (to use time.gmtime()).

get_flags()

현재 설정된 플래그를 지정하는 문자열을 반환합니다. 메시지가 전통적인 형식을 준수하면, 결과는 'R', 'O', 'D', 'F' 및 'A' 각각이 이 순서로 0이나 1회 등장하도록 이어붙인 것입니다.

set_flags(flags)

flags에서 지정한 플래그를 설정하고 다른 모든 플래그를 설정 해제합니다. 매개 변수 flags는 'R', 'O', 'D', 'F' 및 'A' 각각이 0개 이상 등장하도록 임의의 순서로 이어붙인 것이어야 합니다.

add_flag(flag)

다른 플래그를 변경하지 않고 flag로 지정된 플래그를 설정합니다. 한 번에 둘 이상의 플래그를 추가하기 위해, flag가 둘 이상의 문자로 구성된 문자열일 수 있습니다.

remove_flag(flag)

다른 플래그를 변경하지 않고 flag에 의해 지정된 플래그를 설정 해제합니다. 한 번에 둘 이상의 플래그를 제거하기 위해, flag는 둘 이상의 문자로 구성된 문자열일 수 있습니다.

When an mboxMessage instance is created based upon a MaildirMessage instance, a “From “ line is generated based upon the MaildirMessage instance’s delivery date, and the following conversions take place:

결과 상태

MaildirMessage 상태

R 플래그

S 플래그

O 플래그

“cur” 하위 디렉터리

D 플래그

T 플래그

F 플래그

F 플래그

A 플래그

R 플래그

When an mboxMessage instance is created based upon an MHMessage instance, the following conversions take place:

결과 상태

MHMessage 상태

R 플래그와 O 플래그

“unseen” 시퀀스 없음

O 플래그

“unseen” 시퀀스

F 플래그

“flagged” 시퀀스

A 플래그

“replied” 시퀀스

When an mboxMessage instance is created based upon a BabylMessage instance, the following conversions take place:

결과 상태

BabylMessage 상태

R 플래그와 O 플래그

“unseen” 레이블 없음

O 플래그

“unseen” 레이블

D 플래그

“deleted” 레이블

A 플래그

“answered” 레이블

When a mboxMessage instance is created based upon an MMDFMessage instance, the “From “ line is copied and all flags directly correspond:

결과 상태

MMDFMessage 상태

R 플래그

R 플래그

O 플래그

O 플래그

D 플래그

D 플래그

F 플래그

F 플래그

A 플래그

A 플래그

MHMessage objects

class mailbox.MHMessage(message=None)

MH 특정 동작을 갖는 메시지. 매개 변수 message는 Message 생성자와 같은 의미입니다.

MH 메시지는 전통적인 의미에서 마크나 플래그를 지원하지 않지만, 임의 메시지의 논리적 그룹인 시퀀스를 지원합니다. 일부 메일 읽기 프로그램(표준 mh와 nmh는 아니지만)은 다음과 같이 다른 형식에서 플래그를 사용하는 것과 거의 같은 방식으로 시퀀스를 사용합니다:

시퀀스

설명

unseen

읽지 않았지만, 이전에 MUA에서 감지했습니다.

replied

답장함

flagged

중요하다고 표시됨

MHMessage instances offer the following methods:

get_sequences()

이 메시지를 포함하는 시퀀스의 이름 리스트를 반환합니다.

set_sequences(sequences)

이 메시지를 포함하는 시퀀스의 리스트를 설정합니다.

add_sequence(sequence)

이 메시지를 포함하는 시퀀스의 리스트에 sequence를 추가합니다.

remove_sequence(sequence)

이 메시지를 포함하는 시퀀스의 리스트에서 sequence를 제거합니다.

When an MHMessage instance is created based upon a MaildirMessage instance, the following conversions take place:

결과 상태

MaildirMessage 상태

“unseen” 시퀀스

S 플래그 없음

“replied” 시퀀스

R 플래그

“flagged” 시퀀스

F 플래그

When an MHMessage instance is created based upon an mboxMessage or MMDFMessage instance, the Status and X-Status headers are omitted and the following conversions take place:

결과 상태

mboxMessage나 MMDFMessage 상태

“unseen” 시퀀스

R 플래그 없음

“replied” 시퀀스

A 플래그

“flagged” 시퀀스

F 플래그

When an MHMessage instance is created based upon a BabylMessage instance, the following conversions take place:

결과 상태

BabylMessage 상태

“unseen” 시퀀스

“unseen” 레이블

“replied” 시퀀스

“answered” 레이블

BabylMessage objects

class mailbox.BabylMessage(message=None)

Babyl 특정 동작을 갖는 메시지. 매개 변수 message는 Message 생성자와 같은 의미입니다.

어트리뷰트(attributes)라고 부르는 특정 메시지 레이블은 관례에 따라 특별한 의미를 갖도록 정의됩니다. 어트리뷰트는 다음과 같습니다:

레이블

설명

unseen

읽지 않았지만, 이전에 MUA에서 감지했습니다.

deleted

후에 삭제하기 위해 표시함

filed

다른 파일이나 사서함에 복사됨

answered

답장함

forwarded

전달됨

edited

사용자가 수정했음

resent

다시 보냈음

By default, Rmail displays only visible headers. The BabylMessage class, though, uses the original headers because they are more complete. Visible headers may be accessed explicitly if desired.

BabylMessage instances offer the following methods:

get_labels()

메시지의 레이블 리스트를 반환합니다.

set_labels(labels)

메시지의 레이블 리스트를 labels로 설정합니다.

add_label(label)

메시지의 레이블 리스트에 label을 추가합니다.

remove_label(label)

메시지의 레이블 리스트에서 label을 제거합니다.

get_visible()

Return a Message instance whose headers are the message’s visible headers and whose body is empty.

set_visible(visible)

메시지의 가시적 헤더를 message의 헤더와 같게 설정합니다. 매개 변수 visible은 Message 인스턴스, email.message.Message 인스턴스, 문자열 또는 파일류 객체(텍스트 모드로 열어야 합니다)여야 합니다.

update_visible()

When a BabylMessage instance’s original headers are modified, the visible headers are not automatically modified to correspond. This method updates the visible headers as follows: each visible header with a corresponding original header is set to the value of the original header, each visible header without a corresponding original header is removed, and any of Date, From, Reply-To, To, CC, and Subject that are present in the original headers but not the visible headers are added to the visible headers.

When a BabylMessage instance is created based upon a MaildirMessage instance, the following conversions take place:

결과 상태

MaildirMessage 상태

“unseen” 레이블

S 플래그 없음

“deleted” 레이블

T 플래그

“answered” 레이블

R 플래그

“forwarded” 레이블

P 플래그

When a BabylMessage instance is created based upon an mboxMessage or MMDFMessage instance, the Status and X-Status headers are omitted and the following conversions take place:

결과 상태

mboxMessage나 MMDFMessage 상태

“unseen” 레이블

R 플래그 없음

“deleted” 레이블

D 플래그

“answered” 레이블

A 플래그

When a BabylMessage instance is created based upon an MHMessage instance, the following conversions take place:

결과 상태

MHMessage 상태

“unseen” 레이블

“unseen” 시퀀스

“answered” 레이블

“replied” 시퀀스

MMDFMessage objects

class mailbox.MMDFMessage(message=None)

MMDF 특정 동작을 갖는 메시지. 매개 변수 message는 Message 생성자와 같은 의미입니다.

mbox 사서함의 메시지와 마찬가지로, MMDF 메시지는 보낸 사람의 주소와 배달 날짜가 “From “으로 시작하는 첫 줄에 저장됩니다. 마찬가지로, 메시지의 상태를 나타내는 플래그는 일반적으로 Status와 X-Status 헤더에 저장됩니다.

MMDF 메시지의 전통적인 플래그는 mbox 메시지의 플래그와 동일하며 다음과 같습니다:

플래그

의미

설명

R

읽었음

읽었음

O

오래되었음

전에 MUA에서 감지됨

D

삭제됨

후에 삭제하기 위해 표시함

F

깃발 표시

중요하다고 표시됨

A

답변함

답장함

“R”과 “O” 플래그는 Status 헤더에 저장되고, “D”, “F” 및 “A” 플래그는 X-Status 헤더에 저장됩니다. 플래그와 헤더는 일반적으로 언급된 순서대로 나타납니다.

MMDFMessage instances offer the following methods, which are identical to those offered by mboxMessage:

get_from()

mbox 사서함에서 메시지의 시작을 표시하는 “From “ 줄을 나타내는 문자열을 반환합니다. 선행 “From “과 후행 줄넘김은 제외됩니다.

set_from(from_, time_=None)

Set the “From “ line to from_, which should be specified without a leading “From “ or trailing newline. For convenience, time_ may be specified and will be formatted appropriately and appended to from_. If time_ is specified, it should be a time.struct_time instance, a tuple suitable for passing to time.strftime(), or True (to use time.gmtime()).

get_flags()

현재 설정된 플래그를 지정하는 문자열을 반환합니다. 메시지가 전통적인 형식을 준수하면, 결과는 'R', 'O', 'D', 'F' 및 'A' 각각이 이 순서로 0이나 1회 등장하도록 이어붙인 것입니다.

set_flags(flags)

flags에서 지정한 플래그를 설정하고 다른 모든 플래그를 설정 해제합니다. 매개 변수 flags는 'R', 'O', 'D', 'F' 및 'A' 각각이 0개 이상 등장하도록 임의의 순서로 이어붙인 것이어야 합니다.

add_flag(flag)

다른 플래그를 변경하지 않고 flag로 지정된 플래그를 설정합니다. 한 번에 둘 이상의 플래그를 추가하기 위해, flag가 둘 이상의 문자로 구성된 문자열일 수 있습니다.

remove_flag(flag)

다른 플래그를 변경하지 않고 flag에 의해 지정된 플래그를 설정 해제합니다. 한 번에 둘 이상의 플래그를 제거하기 위해, flag는 둘 이상의 문자로 구성된 문자열일 수 있습니다.

When an MMDFMessage instance is created based upon a MaildirMessage instance, a “From “ line is generated based upon the MaildirMessage instance’s delivery date, and the following conversions take place:

결과 상태

MaildirMessage 상태

R 플래그

S 플래그

O 플래그

“cur” 하위 디렉터리

D 플래그

T 플래그

F 플래그

F 플래그

A 플래그

R 플래그

When an MMDFMessage instance is created based upon an MHMessage instance, the following conversions take place:

결과 상태

MHMessage 상태

R 플래그와 O 플래그

“unseen” 시퀀스 없음

O 플래그

“unseen” 시퀀스

F 플래그

“flagged” 시퀀스

A 플래그

“replied” 시퀀스

When an MMDFMessage instance is created based upon a BabylMessage instance, the following conversions take place:

결과 상태

BabylMessage 상태

R 플래그와 O 플래그

“unseen” 레이블 없음

O 플래그

“unseen” 레이블

D 플래그

“deleted” 레이블

A 플래그

“answered” 레이블

When an MMDFMessage instance is created based upon an mboxMessage instance, the “From “ line is copied and all flags directly correspond:

결과 상태

mboxMessage 상태

R 플래그

R 플래그

O 플래그

O 플래그

D 플래그

D 플래그

F 플래그

F 플래그

A 플래그

A 플래그

예외

The following exception classes are defined in the mailbox module:

exception mailbox.Error

기타 모든 다른 모듈 특정 예외에 대한 베이스 클래스.

exception mailbox.NoSuchMailboxError

사서함이 기대되지만 찾을 수 없을 때 발생합니다, 가령 존재하지 않는 경로로 (그리고 False로 설정된 create 매개 변수를 사용하여) Mailbox 서브 클래스를 인스턴스 화하거나, 존재하지 않는 폴더를 열 때.

exception mailbox.NotEmptyError

사서함이 비어 있지 않지만 비어있을 것으로 기대될 때 발생합니다, 가령 메시지가 포함된 폴더를 삭제할 때.

exception mailbox.ExternalClashError

Raised when some mailbox-related condition beyond the control of the program causes it to be unable to proceed, such as when failing to acquire a lock that another program already holds a lock, or when a uniquely generated file name already exists.

exception mailbox.FormatError

파일의 데이터를 구문 분석할 수 없을 때 발생합니다, 가령 MH 인스턴스가 손상된 .mh_sequences 파일을 읽으려고 할 때.

예

사서함에 있는 모든 흥미롭게 보이는 메시지의 제목을 인쇄하는 간단한 예:

import mailbox
for message in mailbox.mbox('~/mbox'):
    subject = message['subject']       # Could possibly be None.
    if subject and 'python' in subject.lower():
        print(subject)

변환할 수 있는 모든 형식별 정보를 변환하면서, Babyl 사서함에서 MH 사서함으로 모든 메일을 복사하려면:

import mailbox
destination = mailbox.MH('~/Mail')
destination.lock()
for message in mailbox.Babyl('~/RMAIL'):
    destination.add(mailbox.MHMessage(message))
destination.flush()
destination.unlock()

이 예에서는 여러 메일링 리스트로부터의 메일을 다른 사서함으로 정렬하여 넣고, 다른 프로그램에 의한 동시 수정으로 인한 메일 손상, 프로그램 중단으로 인한 메일 손실 또는 사서함에 있는 잘못된 메시지로 인한 조기 종료를 방지하도록 주의합니다:

import mailbox
import email.errors

list_names = ('python-list', 'python-dev', 'python-bugs')

boxes = {name: mailbox.mbox('~/email/%s' % name) for name in list_names}
inbox = mailbox.Maildir('~/Maildir', factory=None)

for key in inbox.iterkeys():
    try:
        message = inbox[key]
    except email.errors.MessageParseError:
        continue                # The message is malformed. Just leave it.

    for name in list_names:
        list_id = message['list-id']
        if list_id and name in list_id:
            # Get mailbox to use
            box = boxes[name]

            # Write copy to disk before removing original.
            # If there's a crash, you might duplicate a message, but
            # that's better than losing a message completely.
            box.lock()
            box.add(message)
            box.flush()
            box.unlock()

            # Remove original message
            inbox.lock()
            inbox.discard(key)
            inbox.flush()
            inbox.unlock()
            break               # Found destination, so stop looking.

for box in boxes.itervalues():
    box.close()

mimetypes — Map filenames to MIME types

소스 코드: Lib/mimetypes.py [https://github.com/python/cpython/tree/main/Lib/mimetypes.py]

mimetypes 모듈은 파일명이나 URL과 파일명 확장자와 연관된 MIME 유형 간의 변환을 제공합니다. 변환은 파일명에서 MIME 유형으로, MIME 유형에서 파일 이름 확장자로 제공됩니다; 후자의 변환에서는 인코딩이 지원되지 않습니다.

이 모듈은 하나의 클래스와 여러 편리 함수를 제공합니다. 함수가 이 모듈에 대한 일반 인터페이스이지만, 일부 응용 프로그램은 클래스에도 관심이 있을 수 있습니다.

아래에 설명된 함수는 이 모듈의 기본 인터페이스를 제공합니다. 모듈이 초기화되지 않았으면, 함수가 init()가 설정하는 정보에 의존하면 init()를 호출합니다.

mimetypes.guess_type(url, strict=True)

url로 주어진 파일명, 경로 또는 URL에 기반한 파일의 유형을 추측합니다. URL은 문자열이나 경로류 객체일 수 있습니다.

반환 값은 튜플 (type, encoding)인데, type은 MIME content-type 헤더에 사용할 수 있는 'type/subtype' 형식의 문자열이거나, 유형을 추측할 수 없으면 (없거나 알려지지 않은 확장자) None입니다.

encoding은 인코딩에 사용된 프로그램의 이름(예를 들어, compress나 gzip)이거나, 인코딩이 없으면 None입니다. 인코딩은 Content-Encoding 헤더로 사용하기에 적합합니다, Content-Transfer-Encoding 헤더가 아닙니다. 매핑은 테이블 기반입니다. 인코딩 접미사는 대소 문자를 구분합니다; 유형 접미사는 먼저 대소 문자를 구분해서 시도한 후에, 대소 문자를 구분하지 않고 시도합니다.

선택적 strict 인자는 알려진 MIME 유형 목록을 IANA에 등록된 [https://www.iana.org/assignments/media-types/media-types.xhtml] 공식 유형으로만 제한할지를 지정하는 플래그입니다. strict가 True(기본값)이면 IANA 유형만 지원됩니다; strict가 False일 때, 추가로 표준이 아니지만, 일반적으로 사용되는 MIME 유형도 인식됩니다.

버전 3.8에서 변경: Added support for url being a path-like object.

버전 3.13부터 폐지됨: Passing a file path instead of URL is soft deprecated. Use guess_file_type() for this.

mimetypes.guess_file_type(path, *, strict=True)

Guess the type of a file based on its path, given by path. Similar to the guess_type() function, but accepts a path instead of URL. Path can be a string, a bytes object or a path-like object.

Added in version 3.13.

mimetypes.guess_all_extensions(type, strict=True)

Guess the extensions for a file based on its MIME type, given by type. The return value is a list of strings giving all possible filename extensions, including the leading dot ('.'). The extensions are not guaranteed to have been associated with any particular data stream, but would be mapped to the MIME type type by guess_type() and guess_file_type().

선택적 strict 인자는 guess_type() 함수에서와 같은 의미를 가집니다.

mimetypes.guess_extension(type, strict=True)

Guess the extension for a file based on its MIME type, given by type. The return value is a string giving a filename extension, including the leading dot ('.'). The extension is not guaranteed to have been associated with any particular data stream, but would be mapped to the MIME type type by guess_type() and guess_file_type(). If no extension can be guessed for type, None is returned.

선택적 strict 인자는 guess_type() 함수에서와 같은 의미를 가집니다.

일부 추가 함수와 데이터 항목은 모듈의 동작을 제어하는 데 사용할 수 있습니다.

mimetypes.init(files=None)

내부 데이터 구조를 초기화합니다. 주어지면, files는 기본 유형 맵을 보강하는 데 사용해야 하는 파일 이름의 시퀀스여야 합니다. 생략하면, 사용할 파일 이름은 knownfiles에서 가져옵니다; 윈도우에서는, 현재 레지스트리 설정이 로드됩니다. files나 knownfiles에서 명명된 각 파일은 그 앞에서 명명된 파일보다 우선합니다. 반복적으로 init()를 호출할 수 있습니다.

files에 빈 리스트를 지정하면 시스템 기본값이 적용되지 않습니다: 내장 리스트로부터 온 잘 알려진 값만 나타납니다.

files가 None이면 내부 데이터 구조가 초기 기본값으로 완전히 다시 만들어집니다. 이것은 안정적인 연산이며 여러 번 호출 될 때 같은 결과를 생성합니다.

버전 3.2에서 변경: 이전에는, 윈도우 레지스트리 설정이 무시되었습니다.

mimetypes.read_mime_types(filename)

filename 파일이 있으면, 그 파일에 주어진 유형 맵을 로드합니다. 유형 맵은 선행 점('.')을 포함하는 파일명 확장자를 'type/subtype' 형식의 문자열로 매핑하는 딕셔너리로 반환됩니다. filename 파일이 없거나 읽을 수 없으면 None이 반환됩니다.

mimetypes.add_type(type, ext, strict=True)

MIME 유형 type에서 확장자 ext로의 매핑을 추가합니다. 확장자가 이미 알려져 있으면, 새 유형이 이전 유형을 대체합니다. 유형이 이미 알려져 있으면, 확장이 알려진 확장 리스트에 추가됩니다.

strict가 True(기본값)이면, 매핑이 공식 MIME 유형에 추가되고, 그렇지 않으면 비표준 MIME 유형에 추가됩니다.

mimetypes.inited

전역 데이터 구조가 초기화되었는지를 나타내는 플래그. 이것은 init()에 의해 True로 설정됩니다.

mimetypes.knownfiles

일반적으로 설치된 유형 맵 파일 이름의 리스트입니다. 이 파일들은 일반적으로 mime.types로 명명되며 패키지별로 다른 위치에 설치됩니다.

mimetypes.suffix_map

접미사를 접미사에 매핑하는 딕셔너리. 인코딩과 유형이 같은 확장자로 표시되는 인코딩된 파일을 인식하도록 하는 데 사용됩니다. 예를 들어, .tgz 확장자는 인코딩과 유형을 별도로 인식 할 수 있도록, .tar.gz에 매핑됩니다.

mimetypes.encodings_map

파일명 확장자를 인코딩 유형에 매핑하는 딕셔너리.

mimetypes.types_map

파일명 확장자를 MIME 유형에 매핑하는 딕셔너리.

mimetypes.common_types

파일명 확장자를 비표준이지만 일반적으로 발견되는 MIME 유형에 매핑하는 딕셔너리.

모듈의 사용 예:

>>> import mimetypes
>>> mimetypes.init()
>>> mimetypes.knownfiles
['/etc/mime.types', '/etc/httpd/mime.types', ... ]
>>> mimetypes.suffix_map['.tgz']
'.tar.gz'
>>> mimetypes.encodings_map['.gz']
'gzip'
>>> mimetypes.types_map['.tgz']
'application/x-tar-gz'

MimeTypes 객체

MimeTypes 클래스는 하나 이상의 MIME 유형 데이터베이스가 필요한 응용 프로그램에 유용 할 수 있습니다. mimetypes 모듈과 유사한 인터페이스를 제공합니다.

class mimetypes.MimeTypes(filenames=(), strict=True)

이 클래스는 MIME 유형 데이터베이스를 나타냅니다. 기본적으로, 이 모듈의 나머지 부분과 같은 데이터베이스에 대한 액세스를 제공합니다. 초기 데이터베이스는 모듈이 제공하는 것의 사본이며, read()나 readfp() 메서드를 사용하여 추가 mime.types-스타일 파일을 데이터베이스에 로드하여 확장할 수 있습니다. 기본 데이터가 필요하지 않으면, 추가 데이터를 로드하기 전에 매핑 딕셔너리를 지울 수도 있습니다.

선택적 filenames 매개 변수는 기본 데이터베이스의 “위”에 추가 파일을 로드하게 하는 데 사용할 수 있습니다.

suffix_map

접미사를 접미사에 매핑하는 딕셔너리. 인코딩과 유형이 같은 확장자로 표시되는 인코딩된 파일을 인식하도록 하는 데 사용됩니다. 예를 들어, .tgz 확장자는 인코딩과 유형을 별도로 인식 할 수 있도록, .tar.gz에 매핑됩니다. 이것은 초기에는 모듈에 정의된 전역 suffix_map의 사본입니다.

encodings_map

파일명 확장자를 인코딩 유형에 매핑하는 딕셔너리. 이것은 초기에는 모듈에 정의된 전역 encodings_map의 사본입니다.

types_map

파일명 확장자를 MIME 유형으로 매핑하는 두 개의 딕셔너리를 포함하는 튜플: 첫 번째 딕셔너리는 비표준 유형 용이고 두 번째는 표준 유형 용입니다. common_types와 types_map으로 초기화됩니다.

types_map_inv

MIME 타입을 파일명 확장자 리스트로 매핑하는 두 개의 딕셔너리를 포함하는 튜플: 첫 번째 딕셔너리는 비표준 유형 용이고 두 번째는 표준 유형 용입니다. common_types와 types_map으로 초기화됩니다.

guess_extension(type, strict=True)

guess_extension() 함수와 유사하고, 객체의 일부로 저장된 테이블을 사용합니다.

guess_type(url, strict=True)

guess_type() 함수와 유사하고, 객체의 일부로 저장된 테이블을 사용합니다.

guess_file_type(path, *, strict=True)

Similar to the guess_file_type() function, using the tables stored as part of the object.

Added in version 3.13.

guess_all_extensions(type, strict=True)

guess_all_extensions() 함수와 유사하고, 객체의 일부로 저장된 테이블을 사용합니다.

read(filename, strict=True)

filename이라는 이름의 파일에서 MIME 정보를 로드합니다. readfp()를 사용하여 파일을 구문 분석합니다.

strict가 True이면, 정보는 표준 유형 리스트에 추가되고, 그렇지 않으면 비표준 유형 리스트에 추가됩니다.

readfp(fp, strict=True)

열린 파일 fp에서 MIME 유형 정보를 로드합니다. 파일은 표준 mime.types 파일의 형식이어야 합니다.

strict가 True이면, 정보는 표준 유형 리스트에 추가되고, 그렇지 않으면 비표준 유형 리스트에 추가됩니다.

read_windows_registry(strict=True)

윈도우 레지스트리에서 MIME 유형 정보를 로드합니다.

Availability: Windows.

strict가 True이면, 정보는 표준 유형 리스트에 추가되고, 그렇지 않으면 비표준 유형 리스트에 추가됩니다.

Added in version 3.2.

add_type(type, ext, strict=True)

MIME 유형 type에서 확장자 ext로의 매핑을 추가합니다. 확장자가 이미 알려져 있으면, 새 유형이 이전 유형을 대체합니다. 유형이 이미 알려져 있으면, 확장이 알려진 확장 리스트에 추가됩니다.

strict가 True(기본값)이면, 매핑이 공식 MIME 유형에 추가되고, 그렇지 않으면 비표준 MIME 유형에 추가됩니다.

base64 — Base16, Base32, Base64, Base85 Data Encodings

소스 코드: Lib/base64.py [https://github.com/python/cpython/tree/main/Lib/base64.py]

This module provides functions for encoding binary data to printable ASCII characters and decoding such encodings back to binary data. It provides encoding and decoding functions for the encodings specified in RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html], which defines the Base16, Base32, and Base64 algorithms, and for the de-facto standard Ascii85 and Base85 encodings.

The RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html] encodings are suitable for encoding binary data so that it can be safely sent by email, used as parts of URLs, or included as part of an HTTP POST request. The encoding algorithm is not the same as the uuencode program.

There are two interfaces provided by this module. The modern interface supports encoding bytes-like objects to ASCII bytes, and decoding bytes-like objects or strings containing ASCII to bytes. Both base-64 alphabets defined in RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html] (normal, and URL- and filesystem-safe) are supported.

레거시 인터페이스는 문자열로부터의 디코딩을 지원하지 않지만, 파일 객체에서 인코딩과 디코딩하는 함수를 제공합니다. Base64 표준 알파벳만 지원하며, RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html]에 따라 76자마다 개행 문자를 추가합니다. RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html] 지원을 원한다면 아마도 대신 email 패키지를 보고 싶을 것입니다.

버전 3.3에서 변경: ASCII 전용 유니코드 문자열은 이제 최신 인터페이스의 디코딩 함수가 받아들입니다.

버전 3.4에서 변경: 모든 바이트열류 객체는 이제 이 모듈의 모든 인코딩과 디코딩 함수가 받아들입니다. Ascii85/Base85 지원이 추가되었습니다.

최신 인터페이스는 다음과 같은 것들을 제공합니다:

base64.b64encode(s, altchars=None)

Base64를 사용하여 바이트열류 객체 s를 인코딩하고 인코딩된 bytes를 반환합니다.

Optional altchars must be a bytes-like object of length 2 which specifies an alternative alphabet for the + and / characters. This allows an application to e.g. generate URL or filesystem safe Base64 strings. The default is None, for which the standard Base64 alphabet is used.

May assert or raise a ValueError if the length of altchars is not 2. Raises a TypeError if altchars is not a bytes-like object.

base64.b64decode(s, altchars=None, validate=False)

Base64로 인코딩된 바이트열류 객체나 ASCII 문자열 s를 디코딩하고 디코딩된 bytes를 반환합니다.

Optional altchars must be a bytes-like object or ASCII string of length 2 which specifies the alternative alphabet used instead of the + and / characters.

s가 잘못 채워지면(padded) binascii.Error 예외가 발생합니다.

validate가 False(기본값)면, 일반 base-64 알파벳도 대체 알파벳도 아닌 문자는 채우기(padding) 검사 전에 버려집니다. validate가 True면, 입력에 이 알파벳이 아닌 문자가 있으면 binascii.Error가 발생합니다.

For more information about the strict base64 check, see binascii.a2b_base64()

May assert or raise a ValueError if the length of altchars is not 2.

base64.standard_b64encode(s)

표준 Base64 알파벳을 사용하여 바이트열류 객체 s를 인코딩하고 인코딩된 bytes를 반환합니다.

base64.standard_b64decode(s)

표준 Base64 알파벳을 사용하여 바이트열류 객체나 ASCII 문자열 s를 디코딩하고 디코딩된 bytes를 반환합니다.

base64.urlsafe_b64encode(s)

표준 Base64 알파벳에서 + 대신 -를, / 대신 _를 사용하도록 대체한 URL과 파일 시스템에서 안전한 알파벳을 사용하여 바이트열류 객체 s를 인코딩하고, 인코딩된 bytes를 반환합니다. 결과에는 여전히 =가 포함될 수 있습니다.

base64.urlsafe_b64decode(s)

표준 Base64 알파벳에서 + 대신 -를, / 대신 _를 사용하도록 대체한 URL과 파일 시스템에서 안전한 알파벳을 사용하여 바이트열류 객체나 ASCII 문자열 s를 디코딩하고, 디코딩된 bytes를 반환합니다.

base64.b32encode(s)

Base32를 사용하여 바이트열류 객체 s를 인코딩하고 인코딩된 bytes를 반환합니다.

base64.b32decode(s, casefold=False, map01=None)

Base32로 인코딩된 바이트열류 객체나 ASCII 문자열 s를 디코딩하고 디코딩된 bytes를 반환합니다.

선택적 casefold는 소문자 알파벳을 입력으로 사용할 수 있는지를 지정하는 플래그입니다. 보안을 위해, 기본값은 False입니다.

RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html] allows for optional mapping of the digit 0 (zero) to the letter O (oh), and for optional mapping of the digit 1 (one) to either the letter I (eye) or letter L (el). The optional argument map01 when not None, specifies which letter the digit 1 should be mapped to (when map01 is not None, the digit 0 is always mapped to the letter O). For security purposes the default is None, so that 0 and 1 are not allowed in the input.

s가 잘못 채워졌거나(padded) 입력에 알파벳이 아닌 문자가 있으면 binascii.Error가 발생합니다.

base64.b32hexencode(s)

Similar to b32encode() but uses the Extended Hex Alphabet, as defined in RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html].

Added in version 3.10.

base64.b32hexdecode(s, casefold=False)

Similar to b32decode() but uses the Extended Hex Alphabet, as defined in RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html].

This version does not allow the digit 0 (zero) to the letter O (oh) and digit 1 (one) to either the letter I (eye) or letter L (el) mappings, all these characters are included in the Extended Hex Alphabet and are not interchangeable.

Added in version 3.10.

base64.b16encode(s)

Base16을 사용하여 바이트열류 객체 s를 인코딩하고 인코딩된 bytes를 반환합니다.

base64.b16decode(s, casefold=False)

Base16으로 인코딩된 바이트열류 객체나 ASCII 문자열 s를 디코딩하고 디코딩된 bytes를 반환합니다.

선택적 casefold는 소문자 알파벳을 입력으로 사용할 수 있는지를 지정하는 플래그입니다. 보안을 위해, 기본값은 False입니다.

s가 잘못 채워졌거나(padded) 입력에 알파벳이 아닌 문자가 있으면 binascii.Error가 발생합니다.

base64.a85encode(b, *, foldspaces=False, wrapcol=0, pad=False, adobe=False)

Ascii85를 사용하여 바이트열류 객체 b를 인코딩하고 인코딩된 bytes를 반환합니다.

foldspaces는 ‘btoa’ 가 지원하듯이 4개의 연속된 스페이스 (ASCII 0x20) 대신 특수한 짧은 시퀀스 ‘y’ 를 사용하는 선택적 플래그입니다. 이 기능은 “표준” Ascii85 인코딩에서 지원되지 않습니다.

wrapcol controls whether the output should have newline (b'\n') characters added to it. If this is non-zero, each output line will be at most this many characters long, excluding the trailing newline.

pad는 인코딩하기 전에 입력이 4의 배수로 채워졌는지를 제어합니다. btoa 구현은 항상 채운다는 것에 유의하십시오.

adobe는 인코딩된 바이트 시퀀스가 Adobe 구현에서 사용되는 <~와 ~>로 프레임화되는지를 제어합니다.

Added in version 3.4.

base64.a85decode(b, *, foldspaces=False, adobe=False, ignorechars=b' \t\n\r\x0b')

Ascii85로 인코딩된 바이트열류 객체나 ASCII 문자열 b를 디코딩하고 디코딩된 bytes를 반환합니다.

foldspaces는 짧은 시퀀스 ‘y’ 를 4개의 연속 된 스페이스(ASCII 0x20)에 대한 축약으로 받아들여야 하는지를 지정하는 플래그입니다. 이 기능은 “표준” Ascii85 인코딩에서 지원되지 않습니다.

adobe는 입력 시퀀스가 Adobe Ascii85 형식인지(즉 <~ 와 ~> 로 프레임화되었는지)를 제어합니다.

ignorechars는 입력에서 무시할 문자가 포함된 바이트열류 객체나 ASCII 문자열이어야 합니다. 여기에는 공백 문자만 포함되어야 하며, 기본적으로 ASCII의 모든 공백 문자가 포함됩니다.

Added in version 3.4.

base64.b85encode(b, pad=False)

base85를 사용하여 바이트열류 객체 b를 인코딩하고 (예를 들어 git 스타일 바이너리 diff에서 사용되는 것처럼), 인코딩된 bytes를 반환합니다.

pad가 참이면, 입력은 b'\0'으로 채워져서 길이는 인코딩 전에 4바이트의 배수가 됩니다.

Added in version 3.4.

base64.b85decode(b)

base85로 인코딩된 바이트열류 객체나 ASCII 문자열 b를 디코딩하고 디코딩된 bytes를 반환합니다. 필요하면, 채우기는 묵시적으로 제거됩니다.

Added in version 3.4.

base64.z85encode(s)

Encode the bytes-like object s using Z85 (as used in ZeroMQ) and return the encoded bytes. See Z85 specification [https://rfc.zeromq.org/spec/32/] for more information.

Added in version 3.13.

base64.z85decode(s)

Decode the Z85-encoded bytes-like object or ASCII string s and return the decoded bytes. See Z85 specification [https://rfc.zeromq.org/spec/32/] for more information.

Added in version 3.13.

레거시 인터페이스:

base64.decode(input, output)

바이너리 input 파일의 내용을 디코딩하고 결과 바이너리 데이터를 output 파일에 씁니다. input과 output은 파일 객체여야 합니다. input은 input.readline()이 빈 바이트열 객체를 반환할 때까지 읽힙니다.

base64.decodebytes(s)

하나 이상의 base64 인코딩된 데이터 줄을 포함해야 하는 바이트열류 객체 s를 디코딩하고 디코딩된 bytes를 반환합니다.

Added in version 3.1.

base64.encode(input, output)

바이너리 input 파일의 내용을 인코딩하고 base64로 인코딩된 결과 데이터를 output 파일에 씁니다. input과 output은 파일 객체여야 합니다. input은 input.read()이 빈 바이트열 객체를 반환할 때까지 읽힙니다. encode()는 RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html](MIME)에 따라 출력의 76바이트마다 개행 문자(b'\n')를 삽입할 뿐만 아니라, 항상 출력이 개행 문자로 끝나도록 합니다.

base64.encodebytes(s)

임의의 바이너리 데이터를 포함할 수 있는 바이트열류 객체 s를 인코딩하고, RFC 2045 [https://datatracker.ietf.org/doc/html/rfc2045.html] (MIME)에 따라 76바이트의 출력마다 개행(b'\n')이 삽입되고, 후행 개행이 붙은 base64 인코딩된 데이터를 포함하는 bytes를 반환합니다.

Added in version 3.1.

모듈 사용 예:

>>> import base64
>>> encoded = base64.b64encode(b'data to be encoded')
>>> encoded
b'ZGF0YSB0byBiZSBlbmNvZGVk'
>>> data = base64.b64decode(encoded)
>>> data
b'data to be encoded'

Security Considerations

A new security considerations section was added to RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html] (section 12); it’s recommended to review the security section for any code deployed to production.

더 보기

모듈 binascii

ASCII에서 바이너리로, 바이너리에서 ASCII로의 변환이 포함된 지원 모듈.

RFC 1521 [https://datatracker.ietf.org/doc/html/rfc1521.html] - MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies

5.2 절, “Base64 Content-Transfer-Encoding” 은 base64 인코딩의 정의를 제공합니다.

binascii — Convert between binary and ASCII

The binascii module contains a number of methods to convert between binary and various ASCII-encoded binary representations. Normally, you will not use these functions directly but use wrapper modules like base64 instead. The binascii module contains low-level functions written in C for greater speed that are used by the higher-level modules.

참고

a2b_* 함수는 ASCII 문자만 포함하는 유니코드 문자열을 받아들입니다. 다른 함수는 바이트열류 객체(가령 bytes, bytearray 및 버퍼 프로토콜을 지원하는 다른 객체)만 받아들입니다.

버전 3.3에서 변경: ASCII로만 이루어진 유니코드 문자열은 이제 a2b_* 함수에서 허용됩니다.

binascii 모듈은 다음 함수를 정의합니다:

binascii.a2b_uu(string)

한 줄의 UU 인코딩된 데이터 string을 바이너리로 역변환하고 바이너리 데이터를 반환합니다. 마지막 줄을 제외하고는, 줄은 보통 45 (바이너리) 바이트를 포함합니다. 줄 데이터 뒤에는 공백 문자가 올 수 있습니다.

binascii.b2a_uu(data, *, backtick=False)

바이너리 data를 ASCII 문자의 줄로 변환합니다, 반환 값은 개행 문자를 포함하는 변환 된 줄입니다. data의 길이는 최대 45이어야 합니다. backtick가 참이면, 0은 스페이스 대신 '`'으로 표현됩니다.

버전 3.7에서 변경: backtick 매개 변수가 추가되었습니다.

binascii.a2b_base64(string, /, *, strict_mode=False)

base64 데이터 블록을 바이너리로 역변환하고 바이너리 데이터를 반환합니다. 한 번에 한 줄 이상을 전달할 수 있습니다.

If strict_mode is true, only valid base64 data will be converted. Invalid base64 data will raise binascii.Error.

Valid base64:

Conforms to RFC 3548 [https://datatracker.ietf.org/doc/html/rfc3548.html].

Contains only characters from the base64 alphabet.

Contains no excess data after padding (including excess padding, newlines, etc.).

Does not start with a padding.

버전 3.11에서 변경: Added the strict_mode parameter.

binascii.b2a_base64(data, *, newline=True)

바이너리 data를 base64 코딩으로 ASCII 문자의 줄로 변환합니다. 반환 값은 변환된 줄인데, newline이 참이면, 개행 문자를 포함합니다. 이 함수의 출력은 RFC 3548 [https://datatracker.ietf.org/doc/html/rfc3548.html]을 따릅니다.

버전 3.6에서 변경: newline 매개 변수가 추가되었습니다.

binascii.a2b_qp(data, header=False)

quoted-printable data 블록을 바이너리로 역변환하고 바이너리 데이터를 반환합니다. 한 번에 한 줄 이상을 전달할 수 있습니다. 선택적 인자 header가 있고 참이면, 밑줄(underscore)은 스페이스로 디코딩됩니다.

binascii.b2a_qp(data, quotetabs=False, istext=True, header=False)

바이너리 data를 quoted-printable 인코딩으로 ASCII 문자의 줄로 변환합니다. 반환 값은 변환된 줄입니다. 선택적 인자 quotetabs가 있고 참이면, 모든 탭과 스페이스가 인코딩됩니다. 선택적 인자 istext가 있고 참이면, 개행 문자는 인코딩되지 않지만, 후행 공백은 인코딩됩니다. 선택적 인자 header가 있고 참이면, 스페이스는 RFC 1522 [https://datatracker.ietf.org/doc/html/rfc1522.html]에 따라 밑줄로 인코딩됩니다. 선택적 인자 header가 있고 거짓이면, 개행 문자도 함께 인코딩됩니다; 그렇지 않으면 라인 피드(linefeed) 변환이 바이너리 데이터 스트림을 손상할 수 있습니다.

binascii.crc_hqx(data, value)

초기 CRC value로 시작하는, data의 16비트 CRC 값을 계산하고 결과를 반환합니다. 종종 0x1021로 표시되는, CRC-CCITT 다항식 x¹⁶ + x¹² + x⁵ + 1을 사용합니다. 이 CRC는 binhex4 형식에서 사용됩니다.

binascii.crc32(data[, value])

Compute CRC-32, the unsigned 32-bit checksum of data, starting with an initial CRC of value. The default initial CRC is zero. The algorithm is consistent with the ZIP file checksum. Since the algorithm is designed for use as a checksum algorithm, it is not suitable for use as a general hash algorithm. Use as follows:

print(binascii.crc32(b"hello world"))
# Or, in two pieces:
crc = binascii.crc32(b"hello")
crc = binascii.crc32(b" world", crc)
print('crc32 = {:#010x}'.format(crc))

버전 3.0에서 변경: The result is always unsigned.

binascii.b2a_hex(data[, sep[, bytes_per_sep=1]])

binascii.hexlify(data[, sep[, bytes_per_sep=1]])

바이너리 data의 16진수 표현을 반환합니다. data의 모든 바이트는 해당 2자리 16진수 표현으로 변환됩니다. 따라서 반환된 바이트열 객체의 길이는 data 의 두 배입니다.

비슷한 기능(하지만 텍스트 문자열을 반환하는)을 bytes.hex() 메서드를 사용하여 편리하게 액세스할 수도 있습니다.

sep이 지정되면, 단일 문자 문자열이나 바이트열 객체여야 합니다. bytes_per_sep 입력 바이트마다 출력에 삽입됩니다. 구분자 배치는 기본적으로 출력의 오른쪽 끝에서부터 계산됩니다. 왼쪽부터 계산하려면, 음수의 bytes_per_sep 값을 제공하십시오.

>>> import binascii
>>> binascii.b2a_hex(b'\xb9\x01\xef')
b'b901ef'
>>> binascii.hexlify(b'\xb9\x01\xef', '-')
b'b9-01-ef'
>>> binascii.b2a_hex(b'\xb9\x01\xef', b'_', 2)
b'b9_01ef'
>>> binascii.b2a_hex(b'\xb9\x01\xef', b' ', -2)
b'b901 ef'

버전 3.8에서 변경: sep과 bytes_per_sep 매개 변수가 추가되었습니다.

binascii.a2b_hex(hexstr)

binascii.unhexlify(hexstr)

16진수 문자열 hexstr로 표현된 바이너리 데이터를 반환합니다. 이 함수는 b2a_hex()의 역함수입니다. hexstr는 짝수개의 16진수(대소문자 모두 가능합니다)를 포함해야 하며, 그렇지 않으면 Error 예외가 발생합니다.

비슷한 기능(텍스트 문자열 인자만 받아들이지만, 공백에 대해 더 느슨한)을 bytes.fromhex() 클래스 메서드를 사용하여 액세스할 수도 있습니다.

exception binascii.Error

에러 시 발생하는 예외. 이들은 대개 프로그래밍 에러입니다.

exception binascii.Incomplete

불완전한 데이터에서 발생하는 예외. 이들은 일반적으로 프로그래밍 에러가 아니지만, 조금 더 많은 데이터를 읽고 다시 시도하면 처리될 수 있습니다.

더 보기

모듈 base64

RFC 호환 base64 스타일 인코딩으로, 베이스 16, 32, 64 및 85를 지원합니다.

모듈 quopri

MIME 전자 우편 메시지에 사용되는 quoted-printable 인코딩 지원.

quopri — Encode and decode MIME quoted-printable data

소스 코드: Lib/quopri.py [https://github.com/python/cpython/tree/main/Lib/quopri.py]

이 모듈은 RFC 1521 [https://datatracker.ietf.org/doc/html/rfc1521.html]: “MIME (Multipurpose Internet Mail Extensions) 1부: 인터넷 메시지 본문의 형식을 지정하고 설명하기 위한 메커니즘”에 정의된 대로, quoted-printable 전송 인코딩과 디코딩을 수행합니다. quoted-printable 인코딩은 인쇄할 수 없는 문자가 비교적 적은 데이터를 위해 설계되었습니다; base64 모듈을 통해 사용할 수 있는 base64 인코딩 체계는 그래픽 파일을 보낼 때와 같이 그런 문자가 많은 경우 더 압축적입니다.

quopri.decode(input, output, header=False)

input 파일의 내용을 디코딩하고 결과로 디코딩된 바이너리 데이터를 output 파일에 씁니다. input 과 output는 바이너리 파일 객체 여야 합니다. 선택적 인자 header가 있고 참이면, 밑줄은 스페이스로 디코딩됩니다. 이것은 RFC 1522 [https://datatracker.ietf.org/doc/html/rfc1522.html]: “MIME (Multipurpose Internet Mail Extensions) 2부: 비 ASCII 텍스트를 위한 메시지 헤더 확장”에서 설명한 대로 “Q”-인코딩된 헤더를 디코딩하는 데 사용됩니다.

quopri.encode(input, output, quotetabs, header=False)

input 파일의 내용을 인코딩하고 결과 quoted-printable 데이터를 output 파일에 씁니다. input 과 output은 바이너리 파일 객체 여야 합니다. quotetabs는 포함 된 스페이스와 탭을 인코딩할지를 제어하는 비 선택적 플래그입니다; 참이면 그러한 공백 문자를 인코드하고, 거짓이면 인코드하지 않고 남겨둡니다. 줄 끝에 나타나는 공백과 탭은 RFC 1521 [https://datatracker.ietf.org/doc/html/rfc1521.html]에 따라 항상 인코딩됨에 유의하십시오. header는 스페이스를 RFC 1522 [https://datatracker.ietf.org/doc/html/rfc1522.html]에 따라 밑줄로 인코딩할지를 제어하는 플래그입니다.

quopri.decodestring(s, header=False)

decode()와 비슷하지만, 소스 bytes를 받아들이고 해독된 해당 bytes를 반환합니다.

quopri.encodestring(s, quotetabs=False, header=False)

encode()와 비슷하지만, 소스 bytes를 받아들이고 인코딩된 해당 bytes를 반환합니다. 기본적으로 encode() 함수의 quotetabs 매개 변수에 False 값을 보냅니다.

더 보기

모듈 base64

MIME base64 데이터 인코딩과 디코딩

구조화된 마크업 처리 도구

파이썬은 다양한 형태의 구조화된 데이터 마크업을 다루는 다양한 모듈을 지원합니다. 여기에는 SGML (Standard Generalized Markup Language) 및 HTML (Hypertext Markup Language) 을 다루는 모듈과 XML (Extensible Markup Language) 작업을 위한 여러 인터페이스가 포함됩니다.

html — HyperText Markup Language support

escape()

unescape()

html.parser — Simple HTML and XHTML parser

HTMLParser

HTML 구문 분석기 응용 프로그램 예제

HTMLParser 메서드

feed()

close()

reset()

getpos()

get_starttag_text()

handle_starttag()

handle_endtag()

handle_startendtag()

handle_data()

handle_entityref()

handle_charref()

handle_comment()

handle_decl()

handle_pi()

unknown_decl()

예제

html.entities — Definitions of HTML general entities

html5

entitydefs

name2codepoint

codepoint2name

XML 처리 모듈

XML 취약점

The defusedxml Package

xml.etree.ElementTree — The ElementTree XML API

자습서

XML 트리와 엘리먼트

XML 구문 분석하기

비 블로킹 구문 분석을 위한 풀(pull) API

흥미로운 엘리먼트 찾기

XML 파일 수정하기

XML 문서 구축하기

이름 공간이 있는 XML 구문 분석하기

XPath 지원

예

지원되는 XPath 문법

레퍼런스

함수

canonicalize()

Comment()

dump()

fromstring()

fromstringlist()

indent()

iselement()

iterparse()

parse()

ProcessingInstruction()

register_namespace()

SubElement()

tostring()

tostringlist()

XML()

XMLID()

XInclude 지원

예

레퍼런스

함수

default_loader()

include()

Element 객체

Element

tag

text

tail

attrib

clear()

get()

items()

keys()

set()

append()

extend()

find()

findall()

findtext()

insert()

iter()

iterfind()

itertext()

makeelement()

remove()

ElementTree 객체

ElementTree

_setroot()

find()

findall()

findtext()

getroot()

iter()

iterfind()

parse()

write()

QName 객체

QName

TreeBuilder 객체

TreeBuilder

close()

data()

end()

start()

comment()

pi()

doctype()

start_ns()

end_ns()

C14NWriterTarget

XMLParser 객체

XMLParser

close()

feed()

flush()

XMLPullParser 객체

XMLPullParser

feed()

flush()

close()

read_events()

예외

ParseError

code

position

xml.dom — The Document Object Model API

모듈 내용

registerDOMImplementation()

getDOMImplementation()

EMPTY_NAMESPACE

XML_NAMESPACE

XMLNS_NAMESPACE

XHTML_NAMESPACE

DOM의 객체

DOMImplementation 객체

hasFeature()

createDocument()

createDocumentType()

Node 객체

nodeType

parentNode

attributes

previousSibling

nextSibling

childNodes

firstChild

lastChild

localName

prefix

namespaceURI

nodeName

nodeValue

hasAttributes()

hasChildNodes()

isSameNode()

appendChild()

insertBefore()

removeChild()

replaceChild()

normalize()

cloneNode()

NodeList 객체

item()

length

DocumentType 객체

publicId

systemId

internalSubset

name

entities

notations

Document 객체

documentElement

createElement()

createElementNS()

createTextNode()

createComment()

createProcessingInstruction()

createAttribute()

createAttributeNS()

getElementsByTagName()

getElementsByTagNameNS()

Element 객체

tagName

getElementsByTagName()

getElementsByTagNameNS()

hasAttribute()

hasAttributeNS()

getAttribute()

getAttributeNode()

getAttributeNS()

getAttributeNodeNS()

removeAttribute()

removeAttributeNode()

removeAttributeNS()

setAttribute()

setAttributeNode()

setAttributeNodeNS()

setAttributeNS()

Attr 객체

name

localName

prefix

value

NamedNodeMap 객체

length

item()

Comment 객체

data

Text와 CDATASection 객체

data

ProcessingInstruction 객체

target

data

예외

DOMException

DomstringSizeErr

HierarchyRequestErr

IndexSizeErr

InuseAttributeErr

InvalidAccessErr

InvalidCharacterErr

InvalidModificationErr

InvalidStateErr

NamespaceErr

NotFoundErr

NotSupportedErr

NoDataAllowedErr

NoModificationAllowedErr

SyntaxErr

WrongDocumentErr

규격 준수

형 매핑

접근자 메서드

xml.dom.minidom — Minimal DOM implementation

parse()

parseString()

DOM 객체

unlink()

writexml()

toxml()

toprettyxml()

DOM 예제

minidom과 DOM 표준

xml.dom.pulldom — Support for building partial DOM trees

PullDom

SAX2DOM

parse()

parseString()

default_bufsize

DOMEventStream 객체

DOMEventStream

getEvent()

expandNode()

reset()

xml.sax — Support for SAX2 parsers

make_parser()

parse()

parseString()

SAXException

SAXParseException

SAXNotRecognizedException

SAXNotSupportedException

SAXException 객체

getMessage()

getException()

xml.sax.handler — Base classes for SAX handlers

ContentHandler

DTDHandler

EntityResolver

ErrorHandler

LexicalHandler

feature_namespaces

feature_namespace_prefixes

feature_string_interning

feature_validation

feature_external_ges

feature_external_pes

all_features

property_lexical_handler

property_declaration_handler

property_dom_node

property_xml_string

all_properties

ContentHandler 객체

setDocumentLocator()

startDocument()

endDocument()

startPrefixMapping()

endPrefixMapping()

startElement()

endElement()

startElementNS()

endElementNS()

characters()

ignorableWhitespace()

processingInstruction()

skippedEntity()

DTDHandler 객체

notationDecl()

unparsedEntityDecl()

EntityResolver 객체

resolveEntity()

ErrorHandler 객체

error()

fatalError()

warning()

LexicalHandler Objects

comment()

startDTD()

endDTD()

startCDATA()

endCDATA()

xml.sax.saxutils — SAX Utilities

escape()

unescape()

quoteattr()

XMLGenerator

XMLFilterBase

prepare_input_source()

xml.sax.xmlreader — Interface for XML parsers

XMLReader

IncrementalParser

Locator

InputSource

AttributesImpl

AttributesNSImpl

XMLReader 객체

parse()

getContentHandler()

setContentHandler()

getDTDHandler()

setDTDHandler()

getEntityResolver()

setEntityResolver()

getErrorHandler()

setErrorHandler()

setLocale()

getFeature()

setFeature()

getProperty()

setProperty()

IncrementalParser 객체

feed()

close()

reset()

Locator 객체

getColumnNumber()

getLineNumber()

getPublicId()

getSystemId()

InputSource 객체

setPublicId()

getPublicId()

setSystemId()

getSystemId()

setEncoding()

getEncoding()

setByteStream()

getByteStream()

setCharacterStream()

getCharacterStream()

Attributes 인터페이스

getLength()

getNames()

getType()

getValue()

AttributesNS 인터페이스

getValueByQName()

getNameByQName()

getQNameByName()

getQNames()

xml.parsers.expat — Fast XML parsing using Expat

ExpatError

error

XMLParserType

ErrorString()

ParserCreate()

XMLParser 객체

Parse()

ParseFile()

SetBase()

GetBase()

GetInputContext()

ExternalEntityParserCreate()

SetParamEntityParsing()

UseForeignDTD()

SetReparseDeferralEnabled()

GetReparseDeferralEnabled()

buffer_size

buffer_text

buffer_used

ordered_attributes

specified_attributes

ErrorByteIndex

ErrorCode

ErrorColumnNumber

ErrorLineNumber

CurrentByteIndex

CurrentColumnNumber

CurrentLineNumber

XmlDeclHandler()

StartDoctypeDeclHandler()

EndDoctypeDeclHandler()

ElementDeclHandler()

AttlistDeclHandler()

StartElementHandler()

EndElementHandler()

ProcessingInstructionHandler()

CharacterDataHandler()

UnparsedEntityDeclHandler()

EntityDeclHandler()

NotationDeclHandler()

StartNamespaceDeclHandler()

EndNamespaceDeclHandler()

CommentHandler()

StartCdataSectionHandler()

EndCdataSectionHandler()

DefaultHandler()

DefaultHandlerExpand()

NotStandaloneHandler()

ExternalEntityRefHandler()

ExpatError 예외

code

lineno

offset

예

콘텐츠 모델 기술

Expat 에러 상수

codes

messages

XML_ERROR_ASYNC_ENTITY

XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF

XML_ERROR_BAD_CHAR_REF

XML_ERROR_BINARY_ENTITY_REF

XML_ERROR_DUPLICATE_ATTRIBUTE

XML_ERROR_INCORRECT_ENCODING

XML_ERROR_INVALID_TOKEN

XML_ERROR_JUNK_AFTER_DOC_ELEMENT

XML_ERROR_MISPLACED_XML_PI

XML_ERROR_NO_ELEMENTS

XML_ERROR_NO_MEMORY

XML_ERROR_PARAM_ENTITY_REF

XML_ERROR_PARTIAL_CHAR

XML_ERROR_RECURSIVE_ENTITY_REF

XML_ERROR_SYNTAX

XML_ERROR_TAG_MISMATCH

XML_ERROR_UNCLOSED_TOKEN

XML_ERROR_UNDEFINED_ENTITY

XML_ERROR_UNKNOWN_ENCODING

XML_ERROR_UNCLOSED_CDATA_SECTION

XML_ERROR_EXTERNAL_ENTITY_HANDLING

XML_ERROR_NOT_STANDALONE

XML_ERROR_UNEXPECTED_STATE

XML_ERROR_ENTITY_DECLARED_IN_PE

XML_ERROR_FEATURE_REQUIRES_XML_DTD

XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING

XML_ERROR_UNBOUND_PREFIX

XML_ERROR_UNDECLARING_PREFIX

XML_ERROR_INCOMPLETE_PE

XML_ERROR_XML_DECL

XML_ERROR_TEXT_DECL

XML_ERROR_PUBLICID

XML_ERROR_SUSPENDED

XML_ERROR_NOT_SUSPENDED

XML_ERROR_ABORTED

XML_ERROR_FINISHED

XML_ERROR_SUSPEND_PE

XML_ERROR_RESERVED_PREFIX_XML

XML_ERROR_RESERVED_PREFIX_XMLNS

XML_ERROR_RESERVED_NAMESPACE_URI

XML_ERROR_INVALID_ARGUMENT

XML_ERROR_NO_BUFFER

XML_ERROR_AMPLIFICATION_LIMIT_BREACH

html — HyperText Markup Language support

소스 코드: Lib/html/__init__.py [https://github.com/python/cpython/tree/main/Lib/html/__init__.py]

이 모듈은 HTML을 조작하는 유틸리티를 정의합니다.

html.escape(s, quote=True)

문자열 s의 문자 &, < 및 >를 HTML-안전 시퀀스로 변환합니다. HTML에 이러한 문자가 포함될 수 있는 텍스트를 표시해야 할 때 사용하십시오. 선택적 플래그 quote가 참이면, 문자 (") 와 (') 도 변환됩니다; <a href="..."> 에서처럼 따옴표로 구분된 HTML 어트리뷰트에 포함하는 데 도움이 됩니다.

Added in version 3.2.

html.unescape(s)

문자열 s의 모든 이름과 숫자 문자 참조(예를 들어, &gt;, &#62;, &#x3e;)를 해당 유니코드 문자로 변환합니다. 이 함수는 유효하거나 유효하지 않은 문자 참조 모두에 대해 HTML 5 표준에 정의된 규칙과 HTML 5 이름 문자 참조 목록을 사용합니다.

Added in version 3.4.

html 패키지의 서브 모듈은 다음과 같습니다:

html.parser – 관대한 구문 분석 모드가 있는 HTML/XHTML 구문 분석기

html.entities – HTML 엔티티 정의

html.parser — Simple HTML and XHTML parser

소스 코드: Lib/html/parser.py [https://github.com/python/cpython/tree/main/Lib/html/parser.py]

이 모듈은 HTML(HyperText Mark-up Language)와 XHTML 형식의 텍스트 파일을 구문 분석하기 위한 기초로 사용되는 클래스 HTMLParser를 정의합니다.

class html.parser.HTMLParser(*, convert_charrefs=True)

잘못된 마크업을 구문 분석할 수 있는 구문 분석기 인스턴스를 만듭니다.

convert_charrefs가 True(기본값)이면, (script/style 요소에 있는 것을 제외한) 모든 문자 참조(character references)가 자동으로 해당 유니코드 문자로 변환됩니다.

HTMLParser 인스턴스는 HTML 데이터를 받아서 시작 태그, 종료 태그, 텍스트, 주석 및 기타 마크업 요소를 만날 때마다 처리기 메서드를 호출합니다. 사용자는 원하는 동작을 구현하기 위해 HTMLParser의 서브 클래스를 만들고 해당 메서드를 재정의해야 합니다.

이 구문 분석기는 종료 태그가 시작 태그와 일치하는지 검사하거나, 바깥(outer) 요소를 닫음으로써 묵시적으로 닫힌 요소에 대해 종료 태그 처리기를 호출하지 않습니다.

버전 3.4에서 변경: convert_charrefs 키워드 인자가 추가되었습니다.

버전 3.5에서 변경: 인자 convert_charrefs의 기본값은 이제 True입니다.

HTML 구문 분석기 응용 프로그램 예제

기본 예제로, 다음은 HTMLParser 클래스를 사용하여 시작 태그, 종료 태그 및 데이터를 만날 때마다 인쇄하는 간단한 HTML 구문 분석기입니다:

from html.parser import HTMLParser

class MyHTMLParser(HTMLParser):
    def handle_starttag(self, tag, attrs):
        print("Encountered a start tag:", tag)

    def handle_endtag(self, tag):
        print("Encountered an end tag :", tag)

    def handle_data(self, data):
        print("Encountered some data  :", data)

parser = MyHTMLParser()
parser.feed('<html><head><title>Test</title></head>'
            '<body><h1>Parse me!</h1></body></html>')

출력은 다음과 같습니다:

Encountered a start tag: html
Encountered a start tag: head
Encountered a start tag: title
Encountered some data  : Test
Encountered an end tag : title
Encountered an end tag : head
Encountered a start tag: body
Encountered a start tag: h1
Encountered some data  : Parse me!
Encountered an end tag : h1
Encountered an end tag : body
Encountered an end tag : html

HTMLParser 메서드

HTMLParser 인스턴스에는 다음과 같은 메서드가 있습니다:

HTMLParser.feed(data)

구문 분석기에 텍스트를 입력합니다. 완전한 요소로 구성되어있는 부분까지 처리됩니다; 불완전한 데이터는 더 많은 데이터가 공급되거나 close()가 호출될 때까지 버퍼링 됩니다. data는 str이어야 합니다.

HTMLParser.close()

버퍼링 된 모든 데이터를 마치 파일 끝(end-of-file) 표시가 붙은 것처럼 처리합니다. 이 메서드는 파생 클래스에 의해 입력 끝에서의 추가 처리를 정의하기 위해 재정의될 수 있지만, 재정의된 버전에서는 항상 HTMLParser 베이스 클래스 메서드인 close()를 호출해야 합니다.

HTMLParser.reset()

인스턴스를 재설정합니다. 처리되지 않은 모든 데이터를 잃습니다. 이것은 인스턴스 생성 시에 묵시적으로 호출됩니다.

HTMLParser.getpos()

현재의 줄 번호와 오프셋(offset)을 반환합니다.

HTMLParser.get_starttag_text()

가장 최근에 열렸던 시작 태그의 텍스트를 반환합니다. 이것은 일반적으로 구조화된 처리에 필요하지 않지만, “배치된 대로(as deployed)” HTML을 다루거나 최소한의 변경(어트리뷰트 사이의 공백을 보존할 수 있음, 등등)으로 입력을 다시 생성하는 데 유용할 수 있습니다.

다음 메서드는 데이터나 마크업 요소를 만날 때 호출되며 서브 클래스에서 재정의하려는 용도입니다. 베이스 클래스 구현은 아무 일도 하지 않습니다 (handle_startendtag()는 예외입니다).:

HTMLParser.handle_starttag(tag, attrs)

This method is called to handle the start tag of an element (e.g. <div id="main">).

tag 인자는 소문자로 변환된 태그의 이름입니다. attrs 인자는 태그의 <> 화살괄호 안에 있는 어트리뷰트를 포함하는 (name, value) 쌍의 리스트입니다. name은 소문자로 변환되고, value의 따옴표는 제거되고, 문자와 엔티티 참조는 치환됩니다.

예를 들어, 태그 <A HREF="https://www.cwi.nl/">의 경우, 이 메서드는 handle_starttag('a', [('href', 'https://www.cwi.nl/')])로 호출됩니다.

html.entities의 모든 엔티티 참조가 어트리뷰트 값에서 치환됩니다.

HTMLParser.handle_endtag(tag)

이 메서드는 요소의 종료 태그(예를 들어, </div>)를 처리하기 위해 호출됩니다.

tag 인자는 소문자로 변환된 태그의 이름입니다.

HTMLParser.handle_startendtag(tag, attrs)

handle_starttag()와 비슷하지만, 구문 분석기가 XHTML 스타일의 빈 태그(<img ... />)를 만날 때 호출됩니다. 이 메서드는 이 특정의 어휘 정보(lexical information)가 필요한 서브 클래스에 의해 재정의될 수 있습니다; 기본 구현은 단순히 handle_starttag()와 handle_endtag()를 호출합니다.

HTMLParser.handle_data(data)

이 메서드는 임의의 데이터(예를 들어, 텍스트 노드와 <script>...</script> 및 <style>...</style>의 내용)를 처리하기 위해 호출됩니다.

HTMLParser.handle_entityref(name)

이 메서드는 &name; 형식(예를 들어, &gt;)의 이름있는 문자 참조를 처리하기 위해 호출됩니다. 여기서 name은 일반 엔티티 참조(예를 들어, 'gt')입니다. convert_charrefs가 True이면, 이 메서드는 호출되지 않습니다.

HTMLParser.handle_charref(name)

This method is called to process decimal and hexadecimal numeric character references of the form &#NNN; and &#xNNN;. For example, the decimal equivalent for &gt; is &#62;, whereas the hexadecimal is &#x3E;; in this case the method will receive '62' or 'x3E'. This method is never called if convert_charrefs is True.

HTMLParser.handle_comment(data)

이 메서드는 주석을 만날 때 호출됩니다 (예를 들어, <!--comment-->).

예를 들어, 주석 <!-- comment -->는 이 메서드가 인자 ' comment '로 호출되도록 합니다.

Internet Explorer 조건부 주석(condcoms)의 내용도 이 메서드로 보내지므로, <!--[if IE 9]>IE9-specific content<![endif]-->의 경우, 이 메서드는 '[if IE 9]>IE9-specific content<![endif]'를 받습니다.

HTMLParser.handle_decl(decl)

이 메서드는 HTML doctype 선언(예를 들어, <!DOCTYPE html>)을 처리하기 위해 호출됩니다.

decl 매개 변수는 <!...> 마크업 내의 선언 전체 내용입니다 (예를 들어, 'DOCTYPE html').

HTMLParser.handle_pi(data)

처리 명령(processing instruction)을 만날 때 호출되는 메서드. data 매개 변수에는 전체 처리 명령이 포함됩니다. 예를 들어, 처리 명령 <?proc color='red'>의 경우, 이 메서드는 handle_pi("proc color='red'")로 호출됩니다. 파생 클래스에 의해 재정의되려는 목적입니다; 베이스 클래스 구현은 아무것도 수행하지 않습니다.

참고

HTMLParser 클래스는 처리 명령에 대해 SGML 구문 규칙을 사용합니다. 후행 '?'를 사용하는 XHTML 처리 명령은 '?'가 data에 포함되도록 합니다.

HTMLParser.unknown_decl(data)

이 메서드는 구문 분석기가 인식할 수 없는 선언을 읽었을 때 호출됩니다.

data 매개 변수는 <![...]> 마크업 안에 있는 선언의 전체 내용입니다. 파생 클래스가 재정의하는 것이 때때로 유용합니다. 베이스 클래스 구현은 아무것도 수행하지 않습니다.

예제

다음 클래스는 더 많은 예를 설명하는 데 사용할 구문 분석기를 구현합니다:

from html.parser import HTMLParser
from html.entities import name2codepoint

class MyHTMLParser(HTMLParser):
    def handle_starttag(self, tag, attrs):
        print("Start tag:", tag)
        for attr in attrs:
            print("     attr:", attr)

    def handle_endtag(self, tag):
        print("End tag  :", tag)

    def handle_data(self, data):
        print("Data     :", data)

    def handle_comment(self, data):
        print("Comment  :", data)

    def handle_entityref(self, name):
        c = chr(name2codepoint[name])
        print("Named ent:", c)

    def handle_charref(self, name):
        if name.startswith('x'):
            c = chr(int(name[1:], 16))
        else:
            c = chr(int(name))
        print("Num ent  :", c)

    def handle_decl(self, data):
        print("Decl     :", data)

parser = MyHTMLParser()

doctype 구문 분석하기:

>>> parser.feed('<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" '
...             '"http://www.w3.org/TR/html4/strict.dtd">')
Decl     : DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"

몇 가지 어트리뷰트를 가진 요소와 제목을 구문 분석하기:

>>> parser.feed('<img src="python-logo.png" alt="The Python logo">')
Start tag: img
     attr: ('src', 'python-logo.png')
     attr: ('alt', 'The Python logo')
>>>
>>> parser.feed('<h1>Python</h1>')
Start tag: h1
Data     : Python
End tag  : h1

script와 style 요소의 내용은 더 구문 분석하지 않고 있는 그대로 반환됩니다:

>>> parser.feed('<style type="text/css">#python { color: green }</style>')
Start tag: style
     attr: ('type', 'text/css')
Data     : #python { color: green }
End tag  : style

>>> parser.feed('<script type="text/javascript">'
...             'alert("<strong>hello!</strong>");</script>')
Start tag: script
     attr: ('type', 'text/javascript')
Data     : alert("<strong>hello!</strong>");
End tag  : script

주석 구문 분석하기:

>>> parser.feed('<!-- a comment -->'
...             '<!--[if IE 9]>IE-specific content<![endif]-->')
Comment  :  a comment
Comment  : [if IE 9]>IE-specific content<![endif]

이름있는 문자 참조와 숫자 문자 참조를 구문 분석하고 올바른 문자로 변환합니다 (참고: 이 3개의 참조는 모두 '>'와 동등합니다):

>>> parser.feed('&gt;&#62;&#x3E;')
Named ent: >
Num ent  : >
Num ent  : >

불완전한 청크를 feed()로 보내는 것이 작동합니다만, handle_data()가 두 번 이상 호출될 수 있습니다 (convert_charrefs가 True로 설정되지 않은 한):

>>> for chunk in ['<sp', 'an>buff', 'ered ', 'text</s', 'pan>']:
...     parser.feed(chunk)
...
Start tag: span
Data     : buff
Data     : ered
Data     : text
End tag  : span

잘못된 HTML(예를 들어, 따옴표 처리되지 않은 어트리뷰트)을 구문 분석하는 것도 동작합니다:

>>> parser.feed('<p><a class=link href=#main>tag soup</p ></a>')
Start tag: p
Start tag: a
     attr: ('class', 'link')
     attr: ('href', '#main')
Data     : tag soup
End tag  : p
End tag  : a

html.entities — Definitions of HTML general entities

소스 코드: Lib/html/entities.py [https://github.com/python/cpython/tree/main/Lib/html/entities.py]

이 모듈은 네 가지 딕셔너리 html5, name2codepoint, codepoint2name 와 entitydefs를 정의합니다.

html.entities.html5

HTML5 이름 문자 참조 [1] 를 해당 유니코드 문자에 매핑하는 딕셔너리, 예를 들어 html5['gt;'] == '>'. 후미 세미콜론이 이름에 포함됨에 유의하십시오 (예를 들어 'gt;'). 하지만 일부 이름은 세미콜론 없이도 표준에서 허용됩니다: 이럴 때 이름은 ';'가 있거나 없는 형태가 모두 포함됩니다. html.unescape()도 참조하십시오.

Added in version 3.3.

html.entities.entitydefs

XHTML 1.0 엔티티 정의를 ISO Latin-1의 치환 텍스트에 매핑하는 딕셔너리.

html.entities.name2codepoint

A dictionary that maps HTML4 entity names to the Unicode code points.

html.entities.codepoint2name

A dictionary that maps Unicode code points to HTML4 entity names.

각주

[1]

See https://html.spec.whatwg.org/multipage/named-characters.html#named-character-references

XML 처리 모듈

소스 코드: Lib/xml/ [https://github.com/python/cpython/tree/main/Lib/xml/]

XML 처리를 위한 파이썬의 인터페이스는 xml 패키지로 묶여있습니다.

경고

XML 모듈은 잘못되었거나 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점과 The defusedxml Package 절을 참조하십시오.

xml 패키지의 모듈들은 최소한 하나의 SAX 호환 XML 구문 분석기가 있도록 요구함에 유의해야 합니다. Expat 구문 분석기가 파이썬에 포함되어 있으므로, xml.parsers.expat 모듈을 항상 사용할 수 있습니다.

xml.dom 과 xml.sax 패키지에 대한 설명서는 DOM과 SAX 인터페이스에 대한 파이썬 바인딩의 정의입니다.

XML 처리 서브 모듈은 다음과 같습니다:

xml.etree.ElementTree: ElementTree API, 간단하고 가벼운 XML 프로세서

xml.dom: DOM API 정의

xml.dom.minidom: 최소 DOM 구현

xml.dom.pulldom: 부분 DOM 트리 구축 지원

xml.sax: SAX2 베이스 클래스와 편리 함수

xml.parsers.expat: Expat 구문 분석기 바인딩

XML 취약점

XML 처리 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 공격자는 XML 기능을 악용하여 서비스 거부 공격을 수행하거나, 로컬 파일에 액세스하거나, 다른 기계로 네트워크 연결을 만들거나, 방화벽을 우회할 수 있습니다.

다음 표는 알려진 공격의 개요와 다양한 모듈이 취약한지를 보여줍니다.

종류

sax

etree

minidom

pulldom

xmlrpc

billion laughs(억만 웃음)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

quadratic blowup(이차 폭발)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

Vulnerable (1)

external entity expansion(외부 엔티티 확장)

Safe (5)

Safe (2)

Safe (3)

Safe (5)

안전 (4)

DTD [https://en.wikipedia.org/wiki/Document_type_definition] retrieval(DTD 조회)

Safe (5)

안전

안전

Safe (5)

안전

decompression bomb(압축해제 폭탄)

안전

안전

안전

안전

취약

large tokens

Vulnerable (6)

Vulnerable (6)

Vulnerable (6)

Vulnerable (6)

Vulnerable (6)

Expat 2.4.1 and newer is not vulnerable to the “billion laughs” and “quadratic blowup” vulnerabilities. Items still listed as vulnerable due to potential reliance on system-provided libraries. Check pyexpat.EXPAT_VERSION.

xml.etree.ElementTree doesn’t expand external entities and raises a ParseError when an entity occurs.

xml.dom.minidom은 외부 엔티티를 확장하지 않고 확장되지 않은 엔티티를 그대로 반환합니다.

xmlrpc.client doesn’t expand external entities and omits them.

파이썬 3.7.1부터, 외부 일반 엔티티는 더는 기본적으로 처리되지 않습니다.

Expat 2.6.0 and newer is not vulnerable to denial of service through quadratic runtime caused by parsing large tokens. Items still listed as vulnerable due to potential reliance on system-provided libraries. Check pyexpat.EXPAT_VERSION.

billion laughs(억만 웃음) / exponential entity expansion(지수적 엔티티 확장)

지수적 엔티티 확장으로도 알려진, Billion Laughs [https://en.wikipedia.org/wiki/Billion_laughs] 공격은 여러 수준의 중첩된 엔티티를 사용합니다. 각 엔티티는 다른 엔티티를 여러 번 참조하며, 최종 엔티티 정의에는 작은 문자열이 포함됩니다. 지수적인 확장으로 수 기가바이트의 텍스트가 생성되고 많은 메모리와 CPU 시간이 소모됩니다.

quadratic blowup entity expansion(이차 폭발 엔티티 확장)

A quadratic blowup attack is similar to a Billion Laughs [https://en.wikipedia.org/wiki/Billion_laughs] attack; it abuses entity expansion, too. Instead of nested entities it repeats one large entity with a couple of thousand chars over and over again. The attack isn’t as efficient as the exponential case but it avoids triggering parser countermeasures that forbid deeply nested entities.

external entity expansion(외부 엔티티 확장)

엔티티 선언은 대체 텍스트 이상의 것을 포함할 수 있습니다. 외부 자원이나 지역 파일을 가리킬 수도 있습니다. XML 구문 분석기는 자원에 액세스하고 그 내용을 XML 문서에 포함합니다.

DTD [https://en.wikipedia.org/wiki/Document_type_definition] retrieval(DTD 조회)

파이썬의 xml.dom.pulldom 같은 일부 XML 라이브러리는 원격이나 지역 위치에서 문서 유형 정의(DTD)를 조회합니다. 이 기능은 외부 엔티티 확장 문제와 비슷한 결과를 줍니다.

decompression bomb(압축해제 폭탄)

압축 해제 폭탄(일명 ZIP bomb [https://en.wikipedia.org/wiki/Zip_bomb])은 gzip 압축된 HTTP 스트림이나 LZMA 압축 파일과 같은, 압축된 XML 스트림을 구문 분석할 수 있는 모든 XML 라이브러리에 적용됩니다. 공격자는 전송된 데이터의 양을 3배 이상 줄일 수 있습니다.

large tokens

Expat needs to re-parse unfinished tokens; without the protection introduced in Expat 2.6.0, this can lead to quadratic runtime that can be used to cause denial of service in the application parsing XML. The issue is known as CVE 2023-52425 [https://www.cve.org/CVERecord?id=CVE-2023-52425].

The documentation for defusedxml [https://pypi.org/project/defusedxml/] on PyPI has further information about all known attack vectors with examples and references.

The defusedxml Package

defusedxml [https://pypi.org/project/defusedxml/] is a pure Python package with modified subclasses of all stdlib XML parsers that prevent any potentially malicious operation. Use of this package is recommended for any server code that parses untrusted XML data. The package also ships with example exploits and extended documentation on more XML exploits such as XPath injection.

xml.etree.ElementTree — The ElementTree XML API

소스 코드: Lib/xml/etree/ElementTree.py [https://github.com/python/cpython/tree/main/Lib/xml/etree/ElementTree.py]

xml.etree.ElementTree 모듈은 XML 데이터를 구문 분석하고 만들기 위한 단순하고 효율적인 API를 구현합니다.

버전 3.3에서 변경: 이 모듈은 가능할 때마다 빠른 구현을 사용합니다.

버전 3.3부터 폐지됨: The xml.etree.cElementTree module is deprecated.

경고

xml.etree.ElementTree 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점을 참조하십시오.

자습서

이것은 xml.etree.ElementTree(줄여서 ET)를 사용하기 위한 간단한 자습서입니다. 목표는 모듈의 일부 빌딩 블록과 기본 개념을 예시하는 것입니다.

XML 트리와 엘리먼트

XML은 본질적으로 위계적(hierarchical) 데이터 형식이며, 이를 나타내는 가장 자연스러운 방법은 트리를 사용하는 것입니다. ET에는 이 목적을 위한 두 가지 클래스가 있습니다 - ElementTree는 전체 XML 문서를 트리로 나타내고, Element는 이 트리에 있는 단일 노드를 나타냅니다. 전체 문서와의 상호 작용(파일 읽기와 쓰기)은 일반적으로 ElementTree 수준에서 수행됩니다. 단일 XML 엘리먼트와 해당 서브 엘리먼트와의 상호 작용은 Element 수준에서 수행됩니다.

XML 구문 분석하기

We’ll be using the fictive country_data.xml XML document as the sample data for this section:

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank>4</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank>68</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>

파일을 읽어서 이 데이터를 가져올 수 있습니다:

import xml.etree.ElementTree as ET
tree = ET.parse('country_data.xml')
root = tree.getroot()

또는 문자열에서 직접:

root = ET.fromstring(country_data_as_string)

fromstring()은 문자열에서 Element로 XML을 직접 구문 분석하는데, 구문 분석된 트리의 루트 엘리먼트입니다. 다른 구문 분석 함수는 ElementTree를 만들 수 있습니다. 설명서를 확인하십시오.

Element로서, root에는 태그(tag)와 어트리뷰트 딕셔너리가 있습니다:

>>> root.tag
'data'
>>> root.attrib
{}

또한 우리가 이터레이트 할 수 있는 자식 노드가 있습니다:

>>> for child in root:
...     print(child.tag, child.attrib)
...
country {'name': 'Liechtenstein'}
country {'name': 'Singapore'}
country {'name': 'Panama'}

자식은 중첩되며, 인덱스로 특정 자식 노드에 액세스 할 수 있습니다:

>>> root[0][1].text
'2008'

참고

XML 입력의 모든 엘리먼트가 구문 분석된 트리의 엘리먼트가 되는 것은 아닙니다. 현재, 이 모듈은 입력에서 XML 주석, 처리 명령(processing instructions) 및 문서 형 선언(document type declarations)을 건너뜁니다. 그런데도, XML 텍스트를 구문 분석하는 대신 이 모듈의 API를 사용하여 만들어진 트리에는 주석과 처리 명령이 있을 수 있습니다; 이들은 XML 출력을 생성할 때 포함됩니다. 사용자 정의 TreeBuilder 인스턴스를 XMLParser 생성자에 전달하여 문서 형 선언에 액세스 할 수 있습니다.

비 블로킹 구문 분석을 위한 풀(pull) API

이 모듈이 제공하는 대부분의 구문 분석 함수는 결과를 반환하기 전에 전체 문서를 한 번에 읽도록 요구합니다. XMLParser를 사용하고 점진적으로 데이터를 공급하는 것이 가능하지만, 콜백 대상에 메서드를 호출하는 푸시(push) API로, 대부분의 경우 너무 저 수준이고 불편합니다. 때로 사용자가 실제로 원하는 것은 완전히 구성된 Element 객체의 편리함을 즐기면서 연산을 블로킹하지 않고 XML을 점진적으로 구문 분석할 수 있는 것입니다.

이를 위한 가장 강력한 도구는 XMLPullParser 입니다. XML 데이터를 얻기 위해 블로킹 읽기가 필요하지 않으며, 대신 XMLPullParser.feed() 호출을 통해 점진적으로 데이터가 제공됩니다. 구문 분석된 XML 엘리먼트를 얻으려면, XMLPullParser.read_events()를 호출하십시오. 예를 들면 다음과 같습니다:

>>> parser = ET.XMLPullParser(['start', 'end'])
>>> parser.feed('<mytag>sometext')
>>> list(parser.read_events())
[('start', <Element 'mytag' at 0x7fa66db2be58>)]
>>> parser.feed(' more text</mytag>')
>>> for event, elem in parser.read_events():
...     print(event)
...     print(elem.tag, 'text=', elem.text)
...
end
mytag text= sometext more text

명백한 사용 사례는 XML 데이터가 소켓에서 수신되거나 일부 저장 장치에서 점진적으로 읽히는 비 블로킹 방식으로 작동하는 응용 프로그램입니다. 이럴 때, 블로킹 읽기는 허용되지 않습니다.

XMLPullParser는 매우 유연하기 때문에 더 단순한 사용 사례에 사용하기 불편할 수 있습니다. 응용 프로그램이 XML 데이터 읽기를 블로킹해도 상관없지만, 여전히 점진적인 구문 분석 기능이 필요하면, iterparse()를 살펴보십시오. 큰 XML 문서를 읽을 때 메모리에 전체를 저장하지 않으려는 경우 유용할 수 있습니다.

Where immediate feedback through events is wanted, calling method XMLPullParser.flush() can help reduce delay; please make sure to study the related security notes.

흥미로운 엘리먼트 찾기

Element에는 그 아래의 모든 서브 트리(자식, 자식의 자식 등)를 재귀적으로 이터레이트 하는 데 도움을 주는 유용한 메서드가 있습니다. 예를 들어, Element.iter():

>>> for neighbor in root.iter('neighbor'):
...     print(neighbor.attrib)
...
{'name': 'Austria', 'direction': 'E'}
{'name': 'Switzerland', 'direction': 'W'}
{'name': 'Malaysia', 'direction': 'N'}
{'name': 'Costa Rica', 'direction': 'W'}
{'name': 'Colombia', 'direction': 'E'}

Element.findall()은 현재 엘리먼트의 직접적인 자식인 태그가 있는 엘리먼트만 찾습니다. Element.find()는 특정 태그가 있는 첫 번째 자식을 찾고, Element.text는 엘리먼트의 텍스트 내용에 액세스합니다. Element.get()은 엘리먼트의 어트리뷰트에 액세스합니다:

>>> for country in root.findall('country'):
...     rank = country.find('rank').text
...     name = country.get('name')
...     print(name, rank)
...
Liechtenstein 1
Singapore 4
Panama 68

XPath를 사용하면 찾을 엘리먼트를 더 정교하게 지정할 수 있습니다.

XML 파일 수정하기

ElementTree는 XML 문서를 구축하고 파일에 쓰는 간단한 방법을 제공합니다. ElementTree.write() 메서드가 이 용도입니다.

일단 만들어지면, Element 객체는 필드(가령 Element.text)를 직접 변경하고, 어트리뷰트를 추가하고 수정(Element.set() 메서드)하는 것뿐만 아니라 새로운 자식을 추가하여 (예를 들어 Element.append()) 조작 할 수 있습니다.

각각의 국가(country)의 순위(rank)에 1을 더하고, rank 엘리먼트에 updated 어트리뷰트를 추가하고 싶다고 합시다:

>>> for rank in root.iter('rank'):
...     new_rank = int(rank.text) + 1
...     rank.text = str(new_rank)
...     rank.set('updated', 'yes')
...
>>> tree.write('output.xml')

우리의 XML은 이제 다음과 같습니다:

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>

Element.remove()를 사용하여 엘리먼트를 제거할 수 있습니다. rank가 50보다 큰 모든 국가를 제거하려고 한다고 합시다:

>>> for country in root.findall('country'):
...     # using root.findall() to avoid removal during traversal
...     rank = int(country.find('rank').text)
...     if rank > 50:
...         root.remove(country)
...
>>> tree.write('output.xml')

이터레이션 하는 동안 동시 수정은 파이썬 리스트나 딕셔너리를 이터레이션 할 때와 마찬가지로 문제를 유발할 수 있음에 유의하십시오. 따라서, 이 예제에서는 먼저 root.findall()로 일치하는 모든 엘리먼트를 수집한 다음, 일치 항목 리스트를 이터레이트 합니다.

우리의 XML은 이제 다음과 같습니다:

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
</data>

XML 문서 구축하기

SubElement() 함수는 주어진 엘리먼트에 대해 새로운 서브 엘리먼트를 만드는 편리한 방법을 제공합니다:

>>> a = ET.Element('a')
>>> b = ET.SubElement(a, 'b')
>>> c = ET.SubElement(a, 'c')
>>> d = ET.SubElement(c, 'd')
>>> ET.dump(a)
<a><b /><c><d /></c></a>

이름 공간이 있는 XML 구문 분석하기

XML 입력에 이름 공간(namespaces) [https://en.wikipedia.org/wiki/XML_namespace]이 있으면, prefix:sometag 형식의 접두사가 있는 태그와 어트리뷰트는 {uri}sometag로 확장되는데, 여기서 prefix는 전체 URI로 대체됩니다. 또한 기본 이름 공간(default namespace) [https://www.w3.org/TR/xml-names/#defaulting]이 있으면, 그 전체 URI가 접두사가 없는 모든 태그 앞에 추가됩니다.

다음은 두 개의 이름 공간을 통합한 XML 예제입니다, 하나는 접두사가 “fictional”이고 다른 하나는 기본 이름 공간으로 사용됩니다:

<?xml version="1.0"?>
<actors xmlns:fictional="http://characters.example.com"
        xmlns="http://people.example.com">
    <actor>
        <name>John Cleese</name>
        <fictional:character>Lancelot</fictional:character>
        <fictional:character>Archie Leach</fictional:character>
    </actor>
    <actor>
        <name>Eric Idle</name>
        <fictional:character>Sir Robin</fictional:character>
        <fictional:character>Gunther</fictional:character>
        <fictional:character>Commander Clement</fictional:character>
    </actor>
</actors>

이 XML 예제를 검색하고 탐색하는 한 가지 방법은 find()나 findall()의 xpath에 있는 모든 태그나 어트리뷰트에 URI를 수동으로 추가하는 것입니다:

root = fromstring(xml_text)
for actor in root.findall('{http://people.example.com}actor'):
    name = actor.find('{http://people.example.com}name')
    print(name.text)
    for char in actor.findall('{http://characters.example.com}character'):
        print(' |-->', char.text)

이름 공간이 있는 XML 예제를 검색하는 더 좋은 방법은 여러분 자신의 접두사가 담긴 딕셔너리를 만들고 검색 함수에서 사용하는 것입니다:

ns = {'real_person': 'http://people.example.com',
      'role': 'http://characters.example.com'}

for actor in root.findall('real_person:actor', ns):
    name = actor.find('real_person:name', ns)
    print(name.text)
    for char in actor.findall('role:character', ns):
        print(' |-->', char.text)

이 두 가지 방법 모두 다음과 같이 출력합니다:

John Cleese
 |--> Lancelot
 |--> Archie Leach
Eric Idle
 |--> Sir Robin
 |--> Gunther
 |--> Commander Clement

XPath 지원

이 모듈은 트리에서 엘리먼트를 찾기 위해 XPath 표현식 [https://www.w3.org/TR/xpath]을 제한적으로 지원합니다. 목표는 축약된 문법의 작은 부분 집합을 지원하는 것입니다; 완전한 XPath 엔진은 이 모듈의 범위를 벗어납니다.

예

다음은 모듈의 일부 XPath 기능을 보여주는 예입니다. XML 구문 분석하기 섹션의 countrydata XML 문서를 사용할 것입니다:

import xml.etree.ElementTree as ET

root = ET.fromstring(countrydata)

# Top-level elements
root.findall(".")

# All 'neighbor' grand-children of 'country' children of the top-level
# elements
root.findall("./country/neighbor")

# Nodes with name='Singapore' that have a 'year' child
root.findall(".//year/..[@name='Singapore']")

# 'year' nodes that are children of nodes with name='Singapore'
root.findall(".//*[@name='Singapore']/year")

# All 'neighbor' nodes that are the second child of their parent
root.findall(".//neighbor[2]")

이름 공간이 있는 XML의 경우, 일반적인 정규화된 {namespace}tag 표기법을 사용하십시오:

# All dublin-core "title" tags in the document
root.findall(".//{http://purl.org/dc/elements/1.1/}title")

지원되는 XPath 문법

문법

의미

tag

주어진 태그를 가진 모든 자식 엘리먼트를 선택합니다. 예를 들어, spam은 spam이라는 모든 자식 엘리먼트를 선택하고, spam/egg는 spam이라는 모든 자식의 egg라는 모든 손자를 선택합니다. {namespace}*는 지정된 이름 공간의 모든 태그를 선택하고, {*}spam은 모든 이름 공간의 (또는 이름 공간이 없는) spam이라는 태그를 선택하고, {}*은 이름 공간이 없는 태그만 선택합니다.

버전 3.8에서 변경: 애스터리스크 와일드카드 지원이 추가되었습니다.

*

주석과 처리 명령을 포함한 모든 자식 엘리먼트를 선택합니다. 예를 들어, */egg는 egg라는 모든 손자를 선택합니다.

.

현재 노드를 선택합니다. 상대 경로임을 나타내기 위해 경로의 시작 부분에서 주로 유용합니다.

//

현재 엘리먼트 아래의 모든 수준에서 모든 서브 엘리먼트를 선택합니다. 예를 들어, .//egg는 전체 트리에서 모든 egg 엘리먼트를 선택합니다.

..

부모 엘리먼트를 선택합니다. 경로가 (엘리먼트 find가 호출된) 시작 엘리먼트의 조상에 도달하려고 하면 None을 반환합니다.

[@attrib]

주어진 어트리뷰트를 가진 모든 엘리먼트를 선택합니다.

[@attrib='value']

주어진 어트리뷰트가 주어진 값을 갖는 모든 엘리먼트를 선택합니다. 값은 따옴표를 포함할 수 없습니다.

[@attrib!='value']

Selects all elements for which the given attribute does not have the given value. The value cannot contain quotes.

Added in version 3.10.

[tag]

tag라는 자식이 있는 모든 엘리먼트를 선택합니다. 직계 자식만 지원됩니다.

[.='text']

자손을 포함한 전체 텍스트 내용이 주어진 text와 같은 모든 엘리먼트를 선택합니다.

Added in version 3.7.

[.!='text']

Selects all elements whose complete text content, including descendants, does not equal the given text.

Added in version 3.10.

[tag='text']

자손을 포함한 전체 텍스트 내용이 지정된 text와 같은 이름이 tag인 자식이 있는 모든 엘리먼트를 선택합니다.

[tag!='text']

Selects all elements that have a child named tag whose complete text content, including descendants, does not equal the given text.

Added in version 3.10.

[position]

주어진 위치(position)에 있는 모든 엘리먼트를 선택합니다. 위치(position)는 정수(1이 첫 번째 위치입니다), 표현식 last() (마지막 위치) 또는 마지막 위치에 상대적인 위치(예를 들어 last()-1)일 수 있습니다.

술어 (대괄호 안에 있는 표현식) 앞에는 태그 이름, 애스터리스크 또는 다른 술어가 와야 합니다. position 술어 앞에는 태그 이름이 와야 합니다.

레퍼런스

함수

xml.etree.ElementTree.canonicalize(xml_data=None, *, out=None, from_file=None, **options)

C14N 2.0 [https://www.w3.org/TR/xml-c14n2/] 변환 함수.

Canonicalization is a way to normalise XML output in a way that allows byte-by-byte comparisons and digital signatures. It reduces the freedom that XML serializers have and instead generates a more constrained XML representation. The main restrictions regard the placement of namespace declarations, the ordering of attributes, and ignorable whitespace.

이 함수는 XML 데이터 문자열(xml_data)이나 파일 경로 또는 파일류 객체(from_file)를 입력으로 받아서, 규범적 형식으로 변환한 후, 제공된다면 out 파일(류) 객체를 사용하여 기록하고, 그렇지 않으면 텍스트 문자열로 반환합니다. 출력 파일은 바이트열이 아닌 텍스트를 받습니다. 따라서 utf-8 인코딩을 사용하여 텍스트 모드로 열어야 합니다.

일반적인 사용:

xml_data = "<root>...</root>"
print(canonicalize(xml_data))

with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
    canonicalize(xml_data, out=out_file)

with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
    canonicalize(from_file="inputfile.xml", out=out_file)

구성 options는 다음과 같습니다:

with_comments: 주석을 포함하려면 참으로 설정합니다 (기본값: 거짓).

strip_text: 텍스트 내용 전후의 공백을 제거하려면 참으로 설정합니다

(기본값: 거짓)

rewrite_prefixes: 이름 공간 접두사를 “n{number}” 로 바꾸려면 참으로 설정합니다

(기본값: 거짓)

qname_aware_tags: 텍스트 내용에서 접두사를 대체해야 하는 qname 인식 태그 이름 집합

(기본값: 비어 있음)

qname_aware_attrs: 텍스트 내용에서 접두사를 대체해야 하는 qname 인식 어트리뷰트 이름 집합

(기본값: 비어 있음)

exclude_attrs: 직렬화하면 안 되는 어트리뷰트 이름 집합

exclude_tags: 직렬화하면 안 되는 태그 이름 집합

위의 옵션 목록에서, “집합”은 문자열의 모든 컬렉션이나 이터러블을 가리키며, 순서는 고려하지 않습니다.

Added in version 3.8.

xml.etree.ElementTree.Comment(text=None)

주석 엘리먼트 팩토리. 이 팩토리 함수는 표준 직렬화기가 XML 주석으로 직렬화할 특수 엘리먼트를 만듭니다. 주석 문자열은 바이트 문자열이나 유니코드 문자열일 수 있습니다. text는 주석 문자열이 포함된 문자열입니다. 주석을 나타내는 엘리먼트 인스턴스를 반환합니다.

XMLParser는 주석 객체를 만드는 대신 입력에서 주석을 건너뜀에 유의하십시오. ElementTree는 Element 메서드 중 하나를 사용하여 트리에 삽입된 주석 노드만 포함합니다.

xml.etree.ElementTree.dump(elem)

엘리먼트 트리나 엘리먼트 구조를 sys.stdout에 씁니다. 이 함수는 디버깅에만 사용해야 합니다.

정확한 출력 형식은 구현에 따라 다릅니다. 이 버전에서는, 일반 XML 파일로 기록됩니다.

elem은 엘리먼트 트리나 개별 엘리먼트입니다.

버전 3.8에서 변경: dump() 함수는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

xml.etree.ElementTree.fromstring(text, parser=None)

문자열 상수에서 XML 섹션을 구문 분석합니다. XML()과 같습니다. text는 XML 데이터를 포함하는 문자열입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면, 표준 XMLParser 구문 분석기가 사용됩니다. Element 인스턴스를 반환합니다.

xml.etree.ElementTree.fromstringlist(sequence, parser=None)

문자열 조각의 시퀀스에서 XML 문서를 구문 분석합니다. sequence는 XML 데이터 조각을 포함하는 리스트나 다른 시퀀스입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면 표준 XMLParser 구문 분석기가 사용됩니다. Element 인스턴스를 반환합니다.

Added in version 3.2.

xml.etree.ElementTree.indent(tree, space='  ', level=0)

트리를 시각적으로 들여쓰기하기 위해 서브 트리에 공백을 추가합니다. 이것은 예쁘게 인쇄된 XML 출력을 생성하는 데 사용될 수 있습니다. tree는 Element나 ElementTree 일 수 있습니다. space는 각 들여쓰기 수준에 삽입되는 공백 문자열이며 기본적으로 두 개의 스페이스 문자입니다. 이미 들여쓰기 된 트리 내부에서 부분 서브 트리를 들여 쓰려면, 초기 들여쓰기 수준을 level로 전달하십시오.

Added in version 3.9.

xml.etree.ElementTree.iselement(element)

객체가 유효한 엘리먼트 객체로 보이는지 확인합니다. element는 엘리먼트 인스턴스입니다. 이것이 엘리먼트 객체이면 True를 반환합니다.

xml.etree.ElementTree.iterparse(source, events=None, parser=None)

Parses an XML section into an element tree incrementally, and reports what’s going on to the user. source is a filename or file object containing XML data. events is a sequence of events to report back. The supported events are the strings "start", "end", "comment", "pi", "start-ns" and "end-ns" (the “ns” events are used to get detailed namespace information). If events is omitted, only "end" events are reported. parser is an optional parser instance. If not given, the standard XMLParser parser is used. parser must be a subclass of XMLParser and can only use the default TreeBuilder as a target. Returns an iterator providing (event, elem) pairs; it has a root attribute that references the root element of the resulting XML tree once source is fully read. The iterator has the close() method that closes the internal file object if source is a filename.

iterparse()는 점진적으로 트리를 구축하지만, source(또는 그 이름의 파일)에 대한 블로킹 읽기를 유발함에 유의하십시오. 따라서, 블로킹 읽기를 할 수 없는 응용 프로그램에는 적합하지 않습니다. 완전한 비 블로킹 구문 분석에 대해서는 XMLPullParser를 참조하십시오.

참고

iterparse()는 “start” 이벤트를 방출할 때 시작 태그의 “>” 문자를 보았다는 것만 보장해서, 어트리뷰트는 정의되지만, 텍스트의 내용과 테일(tail) 어트리뷰트는 그 시점에 정의되지 않습니다. 자식 엘리먼트에도 마찬가지로 적용됩니다; 그들은 존재할 수도 그렇지 않을 수도 있습니다.

완전히 채워진 엘리먼트가 필요하면, 대신 “end” 이벤트를 찾으십시오.

버전 3.4부터 폐지됨: parser 인자.

버전 3.8에서 변경: comment와 pi 이벤트가 추가되었습니다.

버전 3.13에서 변경: Added the close() method.

xml.etree.ElementTree.parse(source, parser=None)

XML 섹션을 엘리먼트 트리로 구문 분석합니다. source는 XML 데이터를 포함하는 파일명이나 파일 객체입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면 표준 XMLParser 구문 분석기가 사용됩니다. ElementTree 인스턴스를 반환합니다.

xml.etree.ElementTree.ProcessingInstruction(target, text=None)

PI 엘리먼트 팩토리. 이 팩토리 함수는 XML 처리 명령으로 직렬화될 특수 엘리먼트를 만듭니다. target은 PI 대상을 포함하는 문자열입니다. 주어지면, text는 PI 내용을 포함하는 문자열입니다. 처리 명령을 나타내는 엘리먼트 인스턴스를 반환합니다.

Note that XMLParser skips over processing instructions in the input instead of creating PI objects for them. An ElementTree will only contain processing instruction nodes if they have been inserted into to the tree using one of the Element methods.

xml.etree.ElementTree.register_namespace(prefix, uri)

이름 공간 접두사를 등록합니다. 레지스트리는 전역적이며, 지정된 접두사나 이름 공간 URI에 대한 기존 매핑이 제거됩니다. prefix는 이름 공간 접두사입니다. uri는 이름 공간 URI입니다. 이 이름 공간의 태그와 어트리뷰트는 가능하다면 주어진 접두사로 직렬화됩니다.

Added in version 3.2.

xml.etree.ElementTree.SubElement(parent, tag, attrib={}, **extra)

서브 엘리먼트 팩토리. 이 함수는 엘리먼트 인스턴스를 만들어 기존 엘리먼트에 추가합니다.

엘리먼트 이름, 어트리뷰트 이름 및 어트리뷰트 값은 바이트 문자열이나 유니코드 문자열일 수 있습니다. parent는 부모 엘리먼트입니다. tag는 서브 엘리먼트 이름입니다. attrib는 엘리먼트 어트리뷰트를 포함하는 선택적 딕셔너리입니다. extra에는 키워드 인자로 지정된 추가 어트리뷰트가 포함됩니다. 엘리먼트 인스턴스를 반환합니다.

xml.etree.ElementTree.tostring(element, encoding='us-ascii', method='xml', *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

모든 서브 엘리먼트를 포함하는, XML 엘리먼트의 문자열 표현을 생성합니다. element는 Element 인스턴스입니다. encoding [1] 은 출력 인코딩입니다 (기본값은 US-ASCII입니다). encoding="unicode"를 사용하여 유니코드 문자열을 생성하십시오 (그렇지 않으면 바이트 문자열이 생성됩니다). method는 "xml", "html" 또는 "text"입니다 (기본값은 "xml"입니다). xml_declaration, default_namespace 및 short_empty_elements는 ElementTree.write()에서와 같은 의미입니다. XML 데이터를 포함하는 (선택적으로) 인코딩된 문자열을 반환합니다.

버전 3.4에서 변경: Added the short_empty_elements parameter.

버전 3.8에서 변경: Added the xml_declaration and default_namespace parameters.

버전 3.8에서 변경: tostring() 함수는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

xml.etree.ElementTree.tostringlist(element, encoding='us-ascii', method='xml', *, xml_declaration=None, default_namespace=None, short_empty_elements=True)

모든 서브 엘리먼트를 포함하는, XML 엘리먼트의 문자열 표현을 생성합니다. element는 Element 인스턴스입니다. encoding [1] 은 출력 인코딩입니다 (기본값은 US-ASCII입니다). encoding="unicode"를 사용하여 유니코드 문자열을 생성하십시오 (그렇지 않으면 바이트 문자열이 생성됩니다). method는 "xml", "html" 또는 "text"입니다 (기본값은 "xml"입니다). xml_declaration, default_namespace 및 short_empty_elements는 ElementTree.write()에서와 같은 의미입니다. XML 데이터가 포함된 (선택적으로) 인코딩된 문자열의 리스트를 반환합니다. b"".join(tostringlist(element)) == tostring(element)라는 사실을 제외하고는, 특정 시퀀스를 보장하지는 않습니다.

Added in version 3.2.

버전 3.4에서 변경: Added the short_empty_elements parameter.

버전 3.8에서 변경: Added the xml_declaration and default_namespace parameters.

버전 3.8에서 변경: tostringlist() 함수는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

xml.etree.ElementTree.XML(text, parser=None)

문자열 상수에서 XML 섹션을 구문 분석합니다. 이 함수는 “XML 리터럴”을 파이썬 코드에 내장시키는 데 사용할 수 있습니다. text는 XML 데이터를 포함하는 문자열입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면 표준 XMLParser 구문 분석기가 사용됩니다. Element 인스턴스를 반환합니다.

xml.etree.ElementTree.XMLID(text, parser=None)

문자열 상수에서 XML 섹션을 구문 분석하고, 엘리먼트 id:s 를 엘리먼트로 매핑하는 딕셔너리도 반환합니다. text는 XML 데이터를 포함하는 문자열입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면 표준 XMLParser 구문 분석기가 사용됩니다. Element 인스턴스와 딕셔너리를 포함하는 튜플을 반환합니다.

XInclude 지원

이 모듈은 xml.etree.ElementInclude 도우미 모듈을 통해 XInclude 지시어 [https://www.w3.org/TR/xinclude/]를 제한적으로 지원합니다. 이 모듈은 트리의 정보를 기반으로, 서브 트리와 텍스트 문자열을 엘리먼트 트리에 삽입하는 데 사용할 수 있습니다.

예

다음은 XInclude 모듈의 사용법을 보여주는 예입니다. 현재 문서에 XML 문서를 포함 시키려면, {http://www.w3.org/2001/XInclude}include 엘리먼트를 사용하고 parse 어트리뷰트를 "xml"로 설정하고, href 어트리뷰트를 사용하여 포함할 문서를 지정하십시오.

<?xml version="1.0"?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <xi:include href="source.xml" parse="xml" />
</document>

기본적으로, href 어트리뷰트는 파일 이름으로 취급됩니다. 사용자 정의 로더를 사용하여 이 동작을 대체 할 수 있습니다. 또한 표준 도우미는 XPointer 문법을 지원하지 않음에 유의하십시오.

이 파일을 처리하려면, 평소와 같이 로드하고, 루트 엘리먼트를 xml.etree.ElementTree 모듈에 전달하십시오:

from xml.etree import ElementTree, ElementInclude

tree = ElementTree.parse("document.xml")
root = tree.getroot()

ElementInclude.include(root)

ElementInclude 모듈은 {http://www.w3.org/2001/XInclude}include 엘리먼트를 source.xml 문서의 루트 엘리먼트로 바꿉니다. 결과는 다음과 같습니다:

<document xmlns:xi="http://www.w3.org/2001/XInclude">
  <para>This is a paragraph.</para>
</document>

parse 어트리뷰트가 생략되면, 기본값은 “xml”입니다. href 어트리뷰트는 필수입니다.

텍스트 문서를 포함 시키려면, {http://www.w3.org/2001/XInclude}include 엘리먼트를 사용하고, parse 어트리뷰트를 “text”로 설정하십시오:

<?xml version="1.0"?>
<document xmlns:xi="http://www.w3.org/2001/XInclude">
  Copyright (c) <xi:include href="year.txt" parse="text" />.
</document>

결과는 다음과 같습니다:

<document xmlns:xi="http://www.w3.org/2001/XInclude">
  Copyright (c) 2003.
</document>

레퍼런스

함수

xml.etree.ElementInclude.default_loader(href, parse, encoding=None)

Default loader. This default loader reads an included resource from disk. href is a URL. parse is for parse mode either “xml” or “text”. encoding is an optional text encoding. If not given, encoding is utf-8. Returns the expanded resource. If the parse mode is "xml", this is an Element instance. If the parse mode is "text", this is a string. If the loader fails, it can return None or raise an exception.

xml.etree.ElementInclude.include(elem, loader=None, base_url=None, max_depth=6)

This function expands XInclude directives in-place in tree pointed by elem. elem is either the root Element or an ElementTree instance to find such element. loader is an optional resource loader. If omitted, it defaults to default_loader(). If given, it should be a callable that implements the same interface as default_loader(). base_url is base URL of the original file, to resolve relative include file references. max_depth is the maximum number of recursive inclusions. Limited to reduce the risk of malicious content explosion. Pass None to disable the limitation.

버전 3.9에서 변경: Added the base_url and max_depth parameters.

Element 객체

class xml.etree.ElementTree.Element(tag, attrib={}, **extra)

Element 클래스. 이 클래스는 Element 인터페이스를 정의하고, 이 인터페이스의 참조 구현을 제공합니다.

엘리먼트 이름, 어트리뷰트 이름 및 어트리뷰트 값은 바이트 문자열이나 유니코드 문자열일 수 있습니다. tag는 엘리먼트 이름입니다. attrib는 엘리먼트 어트리뷰트를 포함하는 선택적 딕셔너리입니다. extra에는 키워드 인자로 지정된 추가 어트리뷰트가 포함되어 있습니다.

tag

이 엘리먼트가 나타내는 데이터 종류(즉, 엘리먼트 유형)를 식별하는 문자열.

text

tail

이 어트리뷰트는 엘리먼트와 연관된 추가 데이터를 담는 데 사용될 수 있습니다. 해당 값은 일반적으로 문자열이지만 임의의 응용 프로그램별 객체일 수 있습니다. 엘리먼트가 XML 파일에서 만들어지면, text 어트리뷰트는 엘리먼트의 시작 태그와 첫 번째 자식이나 종료 태그 사이의 텍스트를 담거나 None이고, tail 어트리뷰트는 엘리먼트의 종료 태그와 다음 태그 사이의 텍스트를 담거나 None입니다. 다음과 같은 XML 데이터의 경우

<a><b>1<c>2<d/>3</c></b>4</a>

a 엘리먼트는 text와 tail 어트리뷰트 모두에 대해 None을 갖고, b 엘리먼트는 text "1"과 tail "4"를 갖고, c 엘리먼트는 text "2"와 tail None을 갖고, d 엘리먼트는 text None과 tail "3"을 갖습니다.

엘리먼트의 내부 텍스트를 수집하려면, itertext()를 참조하십시오, 예를 들어 "".join(element.itertext()).

응용 프로그램은 이 어트리뷰트들에 임의의 객체를 저장할 수 있습니다.

attrib

엘리먼트의 어트리뷰트를 포함하는 딕셔너리. attrib 값은 항상 진짜 가변 파이썬 딕셔너리이지만, ElementTree 구현은 다른 내부 표현을 사용하도록 선택하고, 누군가가 요청할 때만 딕셔너리를 만들 수 있습니다. 이러한 구현의 이점을 활용하려면, 가능한 한 아래의 딕셔너리 메서드를 사용하십시오.

다음과 같은 딕셔너리와 유사한 메서드가 엘리먼트 어트리뷰트에서 작동합니다.

clear()

엘리먼트를 재설정합니다. 이 함수는 모든 서브 엘리먼트를 제거하고, 모든 어트리뷰트를 지우고, text 및 tail 어트리뷰트를 None으로 설정합니다.

get(key, default=None)

key라는 이름의 엘리먼트 어트리뷰트를 가져옵니다.

어트리뷰트 값을 반환하거나, 어트리뷰트를 찾을 수 없으면 default를 반환합니다.

items()

엘리먼트 어트리뷰트를 (이름, 값) 쌍의 시퀀스로 반환합니다. 어트리뷰트는 임의의 순서로 반환됩니다.

keys()

엘리먼트 어트리뷰트 이름을 리스트로 반환합니다. 이름은 임의의 순서로 반환됩니다.

set(key, value)

엘리먼트의 key 어트리뷰트를 value로 설정합니다.

다음 메서드는 엘리먼트의 자식(서브 엘리먼트)에서 작동합니다.

append(subelement)

이 엘리먼트의 내부 서브 엘리먼트 리스트 끝에 엘리먼트 subelement를 추가합니다. subelement가 Element가 아니면 TypeError를 발생시킵니다.

extend(subelements)

Appends subelements from an iterable of elements. Raises TypeError if a subelement is not an Element.

Added in version 3.2.

find(match, namespaces=None)

match와 일치하는 첫 번째 서브 엘리먼트를 찾습니다. match는 태그 이름이나 경로일 수 있습니다. 엘리먼트 인스턴스나 None을 반환합니다. namespaces는 이름 공간 접두사에서 전체 이름으로의 선택적 매핑입니다. 표현식에서 접두사가 없는 모든 태그 이름을 지정된 이름 공간으로 이동하려면 ''를 접두사로 전달하십시오.

findall(match, namespaces=None)

태그 이름이나 경로로 일치하는 모든 서브 엘리먼트를 찾습니다. 일치하는 모든 엘리먼트가 문서 순서로 포함된 리스트를 반환합니다. namespaces는 이름 공간 접두사에서 전체 이름으로의 선택적 매핑입니다. 표현식에서 접두사가 없는 모든 태그 이름을 지정된 이름 공간으로 이동하려면 ''를 접두사로 전달하십시오.

findtext(match, default=None, namespaces=None)

match와 일치하는 첫 번째 서브 엘리먼트의 텍스트를 찾습니다. match는 태그 이름이나 경로일 수 있습니다. 일치하는 첫 번째 엘리먼트의 텍스트 내용을 반환하거나, 엘리먼트가 없으면 default를 반환합니다. 일치하는 엘리먼트에 텍스트 내용이 없으면 빈 문자열이 반환됨에 유의하십시오. namespaces는 이름 공간 접두사에서 전체 이름으로의 선택적 매핑입니다. 표현식에서 접두사가 없는 모든 태그 이름을 지정된 이름 공간으로 이동하려면 ''를 접두사로 전달하십시오.

insert(index, subelement)

이 엘리먼트의 지정된 위치에 subelement를 삽입합니다. subelement가 Element가 아니면 TypeError를 발생시킵니다.

iter(tag=None)

현재 엘리먼트를 루트로 하여 트리 이터레이터를 만듭니다. 이터레이터는 이 엘리먼트와 그 아래의 모든 엘리먼트를 문서 순서로 (깊이 우선) 이터레이트 합니다. tag가 None이나 '*'가 아니면, 태그가 tag와 같은 엘리먼트만 이터레이터에서 반환됩니다. 이터레이션 중에 트리 구조가 수정되면, 결과는 정의되지 않습니다.

Added in version 3.2.

iterfind(match, namespaces=None)

태그 이름이나 경로로 일치하는 모든 서브 엘리먼트를 찾습니다. 일치하는 모든 엘리먼트를 문서 순서로 산출하는 이터러블을 반환합니다. namespaces는 이름 공간 접두사에서 전체 이름으로의 선택적 매핑입니다.

Added in version 3.2.

itertext()

텍스트 이터레이터를 만듭니다. 이터레이터는 이 엘리먼트와 모든 서브 엘리먼트를 문서 순서대로 루핑하고, 모든 내부 텍스트를 반환합니다.

Added in version 3.2.

makeelement(tag, attrib)

이 엘리먼트와 같은 유형의 새 엘리먼트 객체를 만듭니다. 이 메서드를 호출하지 말고, 대신 SubElement() 팩토리 함수를 사용하십시오.

remove(subelement)

엘리먼트에서 subelement를 제거합니다. find* 메서드와 달리 이 메서드는 태그값이나 내용이 아닌 인스턴스 아이덴티티를 기준으로 엘리먼트를 비교합니다.

Element 객체는 서브 엘리먼트 작업을 위한 __delitem__(), __getitem__(), __setitem__(), __len__() 시퀀스 형 메서드도 지원합니다.

Caution: Elements with no subelements will test as False. In a future release of Python, all elements will test as True regardless of whether subelements exist. Instead, prefer explicit len(elem) or elem is not None tests.:

element = root.find('foo')

if not element:  # careful!
    print("element not found, or element has no subelements")

if element is None:
    print("element not found")

버전 3.12에서 변경: Testing the truth value of an Element emits DeprecationWarning.

파이썬 3.8 이전에는, 어트리뷰트를 이름으로 정렬하여 엘리먼트의 XML 어트리뷰트의 직렬화 순서를 인위적으로 예측할 수 있도록 했습니다. 이제 보장되는 딕셔너리 순서를 기반으로, 이 임의 재정렬은 파이썬 3.8에서 제거되어 어트리뷰트가 원래 구문 분석되거나 사용자 코드에 의해 만들어진 순서를 유지합니다.

일반적으로, 사용자 코드는 XML Information Set [https://www.w3.org/TR/xml-infoset/]이 정보 전달에서 어트리뷰트 순서를 명시적으로 제외한다는 점에서 구체적인 어트리뷰트 순서에 의존하지 않아야 합니다. 입력의 모든 순서를 다룰 수 있도록 코드를 준비해야 합니다. 예를 들어 암호화 서명이나 테스트 데이터 집합과 같이 결정론적 XML 출력이 필요한 경우, canonicalize() 함수로 규범적 직렬화를 사용할 수 있습니다.

규범적 출력이 적용되지는 않지만, 출력에서 특정 어트리뷰트 순서가 여전히 필요하면, 코드는 코드를 읽는 사람의 지각 불일치를 피하고자, 원하는 순서로 어트리뷰트를 직접 만드는 것을 목표로 해야 합니다. 이를 달성하기 어려운 경우, Element 생성과 독립적으로 순서를 강제하기 위해 직렬화 전에 다음과 같은 조리법을 적용 할 수 있습니다:

def reorder_attributes(root):
    for el in root.iter():
        attrib = el.attrib
        if len(attrib) > 1:
            # adjust attribute order, e.g. by sorting
            attribs = sorted(attrib.items())
            attrib.clear()
            attrib.update(attribs)

ElementTree 객체

class xml.etree.ElementTree.ElementTree(element=None, file=None)

ElementTree 래퍼 클래스. 이 클래스는 전체 엘리먼트 위계를 나타내며, 표준 XML과의 직렬화에 대한 추가 지원을 추가합니다.

element는 루트 엘리먼트입니다. 주어지면 XML file의 내용으로 트리가 초기화됩니다.

_setroot(element)

이 트리의 루트 엘리먼트를 교체합니다. 이것은 트리의 현재 내용을 버리고, 주어진 엘리먼트로 대체합니다. 주의해서 사용하십시오. element는 엘리먼트 인스턴스입니다.

find(match, namespaces=None)

Element.find()와 같습니다, 트리의 루트에서 시작합니다.

findall(match, namespaces=None)

Element.findall()과 같습니다, 트리의 루트에서 시작합니다.

findtext(match, default=None, namespaces=None)

Element.findtext()와 같습니다, 트리의 루트에서 시작합니다.

getroot()

이 트리의 루트 엘리먼트를 반환합니다.

iter(tag=None)

루트 엘리먼트에 대한 트리 이터레이터를 만들고 반환합니다. 이터레이터는 이 트리의 모든 엘리먼트를 섹션 순서대로 루핑합니다. tag는 찾을 태그입니다 (기본값은 모든 엘리먼트를 반환하는 것입니다).

iterfind(match, namespaces=None)

Element.iterfind()와 같습니다, 트리의 루트에서 시작합니다.

Added in version 3.2.

parse(source, parser=None)

이 엘리먼트 트리에 외부 XML 섹션을 로드합니다. source는 파일 이름이나 파일 객체입니다. parser는 선택적 구문 분석기 인스턴스입니다. 지정하지 않으면 표준 XMLParser 구문 분석기가 사용됩니다. 섹션 루트 엘리먼트를 반환합니다.

write(file, encoding='us-ascii', xml_declaration=None, default_namespace=None, method='xml', *, short_empty_elements=True)

엘리먼트 트리를 XML로 파일에 씁니다. file은 파일 이름이거나 쓰기 위해 열린 파일 객체입니다. encoding [1] 은 출력 인코딩입니다 (기본값은 US-ASCII입니다). xml_declaration은 파일에 XML 선언을 추가해야 하는지를 제어합니다. 추가하지 말아야 하면 False, 항상 추가하면 True, US-ASCII나 UTF-8이나 유니코드가 아닐 때만 추가하면 None을 사용하십시오 (기본값은 None입니다). default_namespace는 기본 XML 이름 공간을 설정합니다 (“xmlns”). method는 "xml", "html" 또는 "text"입니다 (기본값은 "xml"입니다). 키워드 전용 short_empty_elements 매개 변수는 내용이 없는 엘리먼트의 포매팅을 제어합니다. True(기본값)이면, 단일 스스로 닫힌 태그로 방출되고, 그렇지 않으면 한 쌍의 시작/종료 태그로 방출됩니다.

출력은 문자열(str)이나 바이너리(bytes)입니다. 이것은 encoding 인자에 의해 제어됩니다. encoding이 "unicode"이면, 출력은 문자열입니다; 그렇지 않으면 바이너리입니다. file이 열린 파일 객체이면 file의 유형과 충돌할 수 있음에 유의하십시오; 문자열을 바이너리 스트림에 쓰거나 그 반대로 하지 않도록 하십시오.

버전 3.4에서 변경: Added the short_empty_elements parameter.

버전 3.8에서 변경: write() 메서드는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

이것은 조작될 XML 파일입니다:

<html>
    <head>
        <title>Example page</title>
    </head>
    <body>
        <p>Moved to <a href="http://example.org/">example.org</a>
        or <a href="http://example.com/">example.com</a>.</p>
    </body>
</html>

첫 번째 문단에 있는 모든 링크의 어트리뷰트 “target”을 변경하는 예:

>>> from xml.etree.ElementTree import ElementTree
>>> tree = ElementTree()
>>> tree.parse("index.xhtml")
<Element 'html' at 0xb77e6fac>
>>> p = tree.find("body/p")     # Finds first occurrence of tag p in body
>>> p
<Element 'p' at 0xb77ec26c>
>>> links = list(p.iter("a"))   # Returns list of all links
>>> links
[<Element 'a' at 0xb77ec2ac>, <Element 'a' at 0xb77ec1cc>]
>>> for i in links:             # Iterates through all found links
...     i.attrib["target"] = "blank"
...
>>> tree.write("output.xhtml")

QName 객체

class xml.etree.ElementTree.QName(text_or_uri, tag=None)

QName 래퍼. 출력에서 이름 공간을 올바르게 처리하기 위해, QName 어트리뷰트 값을 래핑하는 데 사용할 수 있습니다. text_or_uri는 {uri}local 형식으로 QName 값을 포함하는 문자열이거나, tag 인자가 제공되면 QName의 URI 부분입니다. tag가 제공되면, 첫 번째 인자는 URI로 해석되고, 이 인자는 로컬 이름으로 해석됩니다. QName 인스턴스는 불투명합니다.

TreeBuilder 객체

class xml.etree.ElementTree.TreeBuilder(element_factory=None, *, comment_factory=None, pi_factory=None, insert_comments=False, insert_pis=False)

일반 엘리먼트 구조 빌더. 이 빌더는 일련의 start, data, end, comment 및 pi 메서드 호출을 올바른 형식의 엘리먼트 구조로 변환합니다. 이 클래스를 사용하여 사용자 정의 XML 구문 분석기를 사용하거나 다른 XML 형식의 구문 분석기를 사용하는 엘리먼트 구조를 구축할 수 있습니다.

주어지면 element_factory는 두 개의 위치 인자를 받아들이는 콜러블 이어야 합니다: 태그와 어트리뷰트 딕셔너리. 새로운 엘리먼트 인스턴스를 반환할 것으로 기대합니다.

주어지면, comment_factory와 pi_factory 함수는 주석과 처리 명령을 만들기 위해 Comment()와 ProcessingInstruction() 함수처럼 동작해야 합니다. 지정하지 않으면, 기본 팩토리가 사용됩니다. insert_comments 및/또는 insert_pis가 참이면, 주석/처리 명령이 루트 엘리먼트 내에 있으면 (하지만 외부에 있지 않으면) 트리에 삽입됩니다.

close()

빌더 버퍼를 플러시하고, 최상위 문서 엘리먼트를 반환합니다. Element 인스턴스를 반환합니다.

data(data)

현재 엘리먼트에 텍스트를 추가합니다. data는 문자열입니다. 바이트 문자열이거나 유니코드 문자열이어야 합니다.

end(tag)

현재 엘리먼트를 닫습니다. tag는 엘리먼트 이름입니다. 닫힌 엘리먼트를 반환합니다.

start(tag, attrs)

새로운 엘리먼트를 엽니다. tag는 엘리먼트 이름입니다. attrs는 엘리먼트 어트리뷰트를 포함하는 딕셔너리입니다. 열린 엘리먼트를 반환합니다.

comment(text)

주어진 text로 주석을 만듭니다. insert_comments가 참이면, 트리에 추가합니다.

Added in version 3.8.

pi(target, text)

Creates a process instruction with the given target name and text. If insert_pis is true, this will also add it to the tree.

Added in version 3.8.

또한, 사용자 정의 TreeBuilder 객체는 다음 메서드를 제공할 수 있습니다:

doctype(name, pubid, system)

doctype 선언을 처리합니다. name은 doctype 이름입니다. pubid는 공개 식별자입니다. system은 시스템 식별자입니다. 이 메서드는 기본 TreeBuilder 클래스에 없습니다.

Added in version 3.2.

start_ns(prefix, uri)

구문 분석기가 새 이름 공간 선언을 발견할 때마다 이를 정의하는 여는 엘리먼트에 대한 start() 콜백 전에 호출됩니다. prefix는 기본 이름 공간의 경우 ''이고, 그렇지 않으면 선언된 이름 공간 접두사 이름입니다. uri는 이름 공간 URI입니다.

Added in version 3.8.

end_ns(prefix)

이름 공간 접두사 매핑을 선언한 엘리먼트의 end() 콜백 후에, 스코프를 벗어난 prefix의 이름으로 호출됩니다.

Added in version 3.8.

class xml.etree.ElementTree.C14NWriterTarget(write, *, with_comments=False, strip_text=False, rewrite_prefixes=False, qname_aware_tags=None, qname_aware_attrs=None, exclude_attrs=None, exclude_tags=None)

C14N 2.0 [https://www.w3.org/TR/xml-c14n2/] 기록기. 인자는 canonicalize() 함수와 같습니다. 이 클래스는 트리를 구축하지 않지만, write 함수를 사용하여 콜백 이벤트를 직렬화된 형식으로 직접 변환합니다.

Added in version 3.8.

XMLParser 객체

class xml.etree.ElementTree.XMLParser(*, target=None, encoding=None)

이 클래스는 모듈의 저수준 빌딩 블록입니다. 효율적인 이벤트 기반 XML 구문 분석을 위해 xml.parsers.expat을 사용합니다. feed() 메서드를 사용하여 XML 데이터를 점진적으로 공급할 수 있으며, 구문 분석 이벤트는 target 객체에서 콜백을 호출하여 푸시 API로 변환됩니다. target을 생략하면, 표준 TreeBuilder가 사용됩니다. encoding [1] 이 제공되면, 값이 XML 파일에 지정된 인코딩을 대체합니다.

버전 3.8에서 변경: Parameters are now keyword-only. The html argument is no longer supported.

close()

구문 분석기로의 데이터 공급을 완료합니다. 생성 중에 전달된 target의 close() 메서드를 호출한 결과를 반환합니다; 기본적으로, 최상위 문서 엘리먼트입니다.

feed(data)

구문 분석기에 데이터를 공급합니다. data는 인코딩된 데이터입니다.

flush()

Triggers parsing of any previously fed unparsed data, which can be used to ensure more immediate feedback, in particular with Expat >=2.6.0. The implementation of flush() temporarily disables reparse deferral with Expat (if currently enabled) and triggers a reparse. Disabling reparse deferral has security consequences; please see xml.parsers.expat.xmlparser.SetReparseDeferralEnabled() for details.

Note that flush() has been backported to some prior releases of CPython as a security fix. Check for availability of flush() using hasattr() if used in code running across a variety of Python versions.

Added in version 3.13.

XMLParser.feed()는 각 여는 태그마다 target의 start(tag, attrs_dict) 메서드를 호출하고, 닫는 태그마다 end(tag) 메서드를 호출하며, 데이터는 메서드 data(data)로 처리됩니다. 추가로 지원되는 콜백 메서드는, TreeBuilder 클래스를 참조하십시오. XMLParser.close()는 target의 메서드 close()를 호출합니다. XMLParser는 트리 구조 구축에만 사용할 수 있는 것은 아닙니다. 다음은 XML 파일의 최대 깊이를 계산하는 예입니다:

>>> from xml.etree.ElementTree import XMLParser
>>> class MaxDepth:                     # The target object of the parser
...     maxDepth = 0
...     depth = 0
...     def start(self, tag, attrib):   # Called for each opening tag.
...         self.depth += 1
...         if self.depth > self.maxDepth:
...             self.maxDepth = self.depth
...     def end(self, tag):             # Called for each closing tag.
...         self.depth -= 1
...     def data(self, data):
...         pass            # We do not need to do anything with data.
...     def close(self):    # Called when all data has been parsed.
...         return self.maxDepth
...
>>> target = MaxDepth()
>>> parser = XMLParser(target=target)
>>> exampleXml = """
... <a>
...   <b>
...   </b>
...   <b>
...     <c>
...       <d>
...       </d>
...     </c>
...   </b>
... </a>"""
>>> parser.feed(exampleXml)
>>> parser.close()
4

XMLPullParser 객체

class xml.etree.ElementTree.XMLPullParser(events=None)

비 블로킹 응용 프로그램에 적합한 풀 구문 분석기. 입력 측 API는 XMLParser의 것과 유사하지만, 콜백 대상으로 호출을 푸시하는 대신, XMLPullParser는 내부 구문 분석 이벤트 리스트를 수집하여 사용자가 여기서 읽을 수 있도록 합니다. events는 보고할 이벤트의 시퀀스입니다. 지원되는 이벤트는 문자열 "start", "end", "comment", "pi", "start-ns" 및 "end-ns"입니다 (“ns” 이벤트는 자세한 이름 공간 정보를 얻는 데 사용됩니다). events를 생략하면, "end" 이벤트만 보고됩니다.

feed(data)

주어진 바이트열 데이터를 구문 분석기에 공급합니다.

flush()

Triggers parsing of any previously fed unparsed data, which can be used to ensure more immediate feedback, in particular with Expat >=2.6.0. The implementation of flush() temporarily disables reparse deferral with Expat (if currently enabled) and triggers a reparse. Disabling reparse deferral has security consequences; please see xml.parsers.expat.xmlparser.SetReparseDeferralEnabled() for details.

Note that flush() has been backported to some prior releases of CPython as a security fix. Check for availability of flush() using hasattr() if used in code running across a variety of Python versions.

Added in version 3.13.

close()

구문 분석기에 데이터 스트림이 종료되었음을 알립니다. XMLParser.close()와 달리, 이 메서드는 항상 None을 반환합니다. 구문 분석기가 닫힐 때 아직 꺼내지 않은 이벤트는 read_events()로 계속 읽을 수 있습니다.

read_events()

구문 분석기에 공급된 데이터에서 발생한 이벤트에 대한 이터레이터를 반환합니다. 이터레이터는 (event, elem) 쌍을 산출합니다, 여기서 event는 이벤트 유형을 나타내는 문자열(예를 들어 "end")이고 elem은 발견된 Element 객체나, 다음과 같은 기타 문맥 값입니다.

start, end: 현재 엘리먼트.

comment, pi: 현재 주석 / 처리 명령

start-ns: 선언된 이름 공간 매핑을 명명하는 튜플 (prefix, uri)

end-ns: None (향후 버전에서 변경될 수 있습니다)

read_events()에 대한 이전 호출에서 제공된 이벤트는 다시 산출되지 않습니다. 이벤트는 이터레이터에서 꺼낼 때만 내부 큐에서 소비되므로, read_events()에서 얻은 이터레이터에 대해 병렬로 이터레이션 하는 여러 판독기는 예측할 수 없는 결과를 얻게 됩니다.

참고

XMLPullParser 는 “start” 이벤트를 방출할 때 시작 태그의 “>” 문자를 보았다는 것만 보장해서, 어트리뷰트는 정의되지만, 텍스트의 내용과 테일(tail) 어트리뷰트는 그 시점에 정의되지 않습니다. 자식 엘리먼트에도 마찬가지로 적용됩니다; 그들은 존재할 수도 그렇지 않을 수도 있습니다.

완전히 채워진 엘리먼트가 필요하면, 대신 “end” 이벤트를 찾으십시오.

Added in version 3.4.

버전 3.8에서 변경: comment와 pi 이벤트가 추가되었습니다.

예외

class xml.etree.ElementTree.ParseError

XML 구문 분석 에러, 이 모듈의 다양한 구문 분석 메서드가 구문 분석이 실패할 때 발생시킵니다. 이 예외 인스턴스의 문자열 표현에는 사용자 친화적인 에러 메시지가 포함됩니다. 또한, 다음과 같은 어트리뷰트를 사용할 수 있습니다:

code

expat 구문 분석기의 숫자 에러 코드. 에러 코드와 의미의 목록은 xml.parsers.expat 설명서를 참조하십시오.

position

에러가 발생한 위치를 지정하는, line, column 숫자의 튜플.

각주

[1] (1,2,3,4)

XML 출력에 포함된 인코딩 문자열은 적절한 표준을 준수해야 합니다. 예를 들어, “UTF-8”은 유효하지만, “UTF8”은 유효하지 않습니다. https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl and https://www.iana.org/assignments/character-sets/character-sets.xhtml 을 참조하십시오.

xml.dom — The Document Object Model API

소스 코드: Lib/xml/dom/__init__.py [https://github.com/python/cpython/tree/main/Lib/xml/dom/__init__.py]

문서 객체 모델(Document Object Model), 또는 “DOM”은 XML 문서를 액세스하고 수정하기 위한 W3C(World Wide Web Consortium)의 교차 언어 API입니다. DOM 구현은 XML 문서를 트리 구조로 나타내거나, 클라이언트 코드가 이러한 구조를 처음부터 구축 할 수 있도록 합니다. 그런 다음 잘 알려진 인터페이스를 제공하는 객체 집합을 통해 구조에 액세스 할 수 있습니다.

DOM은 무작위 액세스 응용 프로그램에 매우 유용합니다. SAX에서는 한 번에 한 조각의 문서만 볼 수 있습니다. 하나의 SAX 요소를 보고 있는 동안, 다른 SAX 요소에 액세스할 수 없습니다. 텍스트 노드를 보고 있으면, 이것을 포함하는 요소에 액세스할 수 없습니다. SAX 응용 프로그램을 작성할 때는, 문서에서의 프로그램의 위치를 자신의 코드 어딘가에서 추적해야 합니다. SAX는 여러분을 위해 대신해주지 않습니다. 또한, XML 문서를 미리 보아야 한다면, 운이 다했다고 보아야 합니다.

트리에 액세스할 수 없는 이벤트 중심 모델에서는 일부 응용 프로그램이 불가능합니다. 물론 SAX 이벤트에서 트리를 직접 만들 수는 있지만, DOM을 사용하면 그런 코드를 작성하지 않아도 됩니다. DOM은 XML 데이터의 표준 트리 표현입니다.

문서 객체 모델은 W3C에 의해 단계적으로 또는 그들의 용어로는 “수준”으로 정의됩니다. API의 파이썬 매핑은 실질적으로 DOM 수준 2 권장 사항을 기반으로 합니다.

DOM 응용 프로그램은 일반적으로 일부 XML을 DOM으로 구문 분석하는 것으로 시작합니다. 이것을 달성하는 방법은 DOM 수준 1은 전혀 다루지 않으며, 수준 2는 제한된 개선만을 제공합니다: Document 생성 메서드에 대한 액세스를 제공하는 DOMImplementation 객체 클래스가 있습니다만, 구현에 독립적인 방법으로 XML 판독기(reader)/기록기(writer)/Document 구축기(builder)를 액세스하는 방법이 없습니다. 기존 Document 객체 없이 이러한 메서드에 액세스할 수 있는 잘 정의된 방법도 없습니다. 파이썬에서, 각 DOM 구현은 getDOMImplementation() 함수를 제공합니다. DOM 수준 3은 판독기(reader)에 대한 인터페이스를 정의하는 로드/저장 명세를 추가하지만, 아직 파이썬 표준 라이브러리에서는 사용할 수 없습니다.

일단 DOM 문서 객체가 있으면, 프로퍼티와 메서드를 통해 XML 문서의 일부에 액세스 할 수 있습니다. 이러한 프로퍼티는 DOM 명세에 정의되어 있습니다; 레퍼런스 설명서의 이 부분은 파이썬이 명세를 해석하는 방법을 설명합니다.

W3C에서 제공하는 명세는 Java, ECMAScript 및 OMG IDL 용 DOM API를 정의합니다. 여기에 정의된 파이썬 매핑은 대부분 명세의 IDL 버전을 기반으로 하지만, 엄격한 준수는 필요하지 않습니다 (구현은 IDL의 엄격한 매핑을 자유롭게 지원할 수 있습니다). 매핑 요구 사항에 대한 자세한 내용은 규격 준수 절을 참조하십시오.

더 보기

Document Object Model (DOM) Level 2 Specification [https://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/]

파이썬 DOM API의 기반이 되는 W3C 권장 사항.

Document Object Model (DOM) Level 1 Specification [https://www.w3.org/TR/REC-DOM-Level-1/]

xml.dom.minidom이 지원하는 DOM에 대한 W3C 권장 사항.

Python Language Mapping Specification [https://www.omg.org/spec/PYTH/1.2/PDF]

OMG IDL에서 파이썬으로의 매핑을 지정합니다.

모듈 내용

xml.dom에는 다음 함수가 포함되어 있습니다:

xml.dom.registerDOMImplementation(name, factory)

factory 함수를 name이라는 이름으로 등록합니다. 팩토리(factory) 함수는 DOMImplementation 인터페이스를 구현하는 객체를 반환해야 합니다. 팩토리 함수는 호출 때마다 같은 객체를 반환하거나 특정 구현에 적합하다면 새 객체를 반환할 수 있습니다 (예를 들어, 해당 구현이 일부 사용자 정의를 지원하는 경우).

xml.dom.getDOMImplementation(name=None, features=())

적절한 DOM 구현을 반환합니다. name은 잘 알려진 DOM 구현의 모듈 이름이거나, None입니다. None이 아니면, 해당 모듈을 임포트하고 성공하면 DOMImplementation 객체를 반환합니다. 이름이 지정되지 않고, 환경 변수 PYTHON_DOM이 설정되면, 이 변수를 구현을 찾는 데 사용합니다.

이름을 지정하지 않으면, 사용 가능한 구현을 검사하여 필요한 기능 집합이 있는 구현을 찾습니다. 구현을 찾을 수 없으면, ImportError를 발생시킵니다. 기능 목록은 사용 가능한 DOMImplementation 객체의 hasFeature() 메서드로 전달되는 (feature, version) 쌍의 시퀀스여야 합니다.

몇 가지 편의 상수도 제공됩니다:

xml.dom.EMPTY_NAMESPACE

이름 공간이 DOM의 노드와 연결되어 있지 않음을 나타내는 데 사용되는 값. 이것은 일반적으로 노드의 namespaceURI에서 발견되거나, 이름 공간별 메서드에 대한 namespaceURI 매개 변수로 사용됩니다.

xml.dom.XML_NAMESPACE

예약된 접두어 xml과 연관된 이름 공간 URI, Namespaces in XML <https://www.w3.org/TR/REC-xml-names/>에서 정의됩니다 (4절).

xml.dom.XMLNS_NAMESPACE

이름 공간 선언의 이름 공간 URI, Document Object Model (DOM) Level 2 Core Specification [https://www.w3.org/TR/DOM-Level-2-Core/core.html]에서 정의됩니다 (1.1.8 절).

xml.dom.XHTML_NAMESPACE

XHTML 이름 공간의 URI, XHTML 1.0: The Extensible HyperText Markup Language [https://www.w3.org/TR/xhtml1/]에서 정의됩니다 (3.1.1 절).

또한, xml.dom에는 베이스 Node 클래스와 DOM 예외 클래스가 포함됩니다. 이 모듈에서 제공하는 Node 클래스는 DOM 명세에 정의된 메서드나 어트리뷰트를 구현하지 않습니다; 구상(concrete) DOM 구현이 이를 제공해야 합니다. 이 모듈의 일부로 제공되는 Node 클래스는 구상 Node 객체의 nodeType 어트리뷰트에 사용되는 상수를 제공합니다; 그것들은 DOM 명세를 준수하기 위해 모듈 수준이 아니라 클래스 내에 위치합니다.

DOM의 객체

DOM에 대한 결정적인 문서는 W3C의 DOM 명세입니다.

DOM 어트리뷰트는 간단한 문자열 대신 노드로 조작될 수도 있음에 유의하십시오. 하지만 그렇게 해야만 하는 경우는 매우 드물어서, 이 사용법은 아직 문서화되지 않았습니다.

인터페이스

절

목적

DOMImplementation

DOMImplementation 객체

하부 구현에 대한 인터페이스.

Node

Node 객체

문서에 있는 대부분 객체에 대한 베이스 인터페이스.

NodeList

NodeList 객체

노드의 시퀀스를 위한 인터페이스.

DocumentType

DocumentType 객체

문서를 처리하는 데 필요한 선언에 대한 정보.

Document

Document 객체

전체 문서를 나타내는 객체.

Element

Element 객체

문서 계층의 엘리먼트 노드.

Attr

Attr 객체

엘리먼트 노드의 어트리뷰트 값 노드

Comment

Comment 객체

소스 문서에 있는 주석의 표현.

Text

Text와 CDATASection 객체

문서의 텍스트 내용을 포함하는 노드.

ProcessingInstruction

ProcessingInstruction 객체

처리 명령어 표현.

추가 절에서 파이썬에서 DOM 작업을 위해 정의된 예외에 관해 설명합니다.

DOMImplementation 객체

DOMImplementation 인터페이스는 응용 프로그램이 사용 중인 DOM에서 특정 기능의 가용성을 판별할 방법을 제공합니다. DOM 수준 2는 DOMImplementation을 사용하여 새로운 Document와 DocumentType 객체를 만드는 기능을 추가했습니다.

DOMImplementation.hasFeature(feature, version)

문자열 feature와 version 쌍으로 식별되는 기능이 구현되었으면 True를 반환합니다.

DOMImplementation.createDocument(namespaceUri, qualifiedName, doctype)

지정된 namespaceUri와 qualifiedName을 가진 자식 Element 객체를 포함하는 새 Document 객체(DOM의 루트)를 반환합니다. doctype은 createDocumentType()으로 만든 DocumentType 객체거나 None이어야 합니다. 파이썬 DOM API에서, Element 자식이 만들어지지 않음을 표시하기 위해 처음 두 인자는 None일 수 있습니다.

DOMImplementation.createDocumentType(qualifiedName, publicId, systemId)

XML 문서 형 선언에 포함된 정보를 나타내는, 지정된 qualifiedName, publicId 및 systemId 문자열을 캡슐화하는 새 DocumentType 객체를 반환합니다.

Node 객체

XML 문서의 모든 구성 요소는 Node의 서브 클래스입니다.

Node.nodeType

노드 형을 나타내는 정수. 형의 기호 상수는 Node 객체에 있습니다: ELEMENT_NODE, ATTRIBUTE_NODE, TEXT_NODE, CDATA_SECTION_NODE, ENTITY_NODE, PROCESSING_INSTRUCTION_NODE, COMMENT_NODE, DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE. 이것은 읽기 전용 어트리뷰트입니다.

Node.parentNode

현재 노드의 부모, 또는 문서 노드의 경우 None. 값은 항상 Node 객체나 None입니다. Element 노드의 경우, 이것은 부모 엘리먼트가 되는데, 루트 엘리먼트는 예외로, 이때는 Document 객체가 됩니다. Attr 노드의 경우, 항상 None입니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.attributes

어트리뷰트 객체의 NamedNodeMap. 엘리먼트에만 실제 값이 있습니다; 다른 것은 이 어트리뷰트에서 None을 제공합니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.previousSibling

같은 부모를 갖고 이 노드 바로 앞에 있는 노드. 예를 들어 self 엘리먼트의 시작 태그 바로 앞에 오는 종료 태그의 엘리먼트. 물론, XML 문서는 단순히 엘리먼트만으로 구성되지 않기 때문에, 이전 형제(previous sibling)는 텍스트, 주석 또는 뭔가 다른 것이 될 수 있습니다. 이 노드가 부모의 첫 번째 자식이면, 이 어트리뷰트는 None입니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.nextSibling

같은 부모를 갖고 이 노드 바로 뒤에 나오는 노드. previousSibling도 참조하십시오. 이것이 부모의 마지막 자식이면, 이 어트리뷰트는 None입니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.childNodes

이 노드에 포함된 노드의 리스트. 이것은 읽기 전용 어트리뷰트입니다.

Node.firstChild

노드의 첫 번째 자식 (있다면), 또는 None. 이것은 읽기 전용 어트리뷰트입니다.

Node.lastChild

노드의 마지막 자식 (있다면), 또는 None. 이것은 읽기 전용 어트리뷰트입니다.

Node.localName

콜론이 있으면 그 뒤에 오는 tagName의 부분, 그렇지 않으면 전체 tagName. 값은 문자열입니다.

Node.prefix

콜론이 있으면 그 앞에 오는 tagName의 부분, 그렇지 않으면 빈 문자열. 값은 문자열이나 None입니다.

Node.namespaceURI

엘리먼트 이름과 연관된 이름 공간. 이것은 문자열이나 None입니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.nodeName

이는 각 노드 형마다 다른 의미입니다; 자세한 내용은 DOM 명세를 참조하십시오. 여기서 얻는 정보를 항상 다른 프로퍼티에서 얻을 수 있습니다, 가령 엘리먼트의 tagName 프로퍼티나 어트리뷰트의 name 프로퍼티. 모든 노드 형에서, 이 어트리뷰트의 값은 문자열이나 None입니다. 이것은 읽기 전용 어트리뷰트입니다.

Node.nodeValue

이는 각 노드 형마다 다른 의미입니다; 자세한 내용은 DOM 명세를 참조하십시오. 상황은 nodeName과 유사합니다. 값은 문자열이나 None입니다.

Node.hasAttributes()

노드에 어트리뷰트가 있으면 True를 반환합니다.

Node.hasChildNodes()

노드에 자식 노드가 있으면 True를 반환합니다.

Node.isSameNode(other)

other가 이 노드와 같은 노드를 가리키면 True를 반환합니다. 이것은 모든 종류의 프락시 구조를 사용하는 DOM 구현에서 특히 유용합니다 (여러 객체가 같은 노드를 가리킬 수 있기 때문입니다).

참고

이것은 여전히 “작업 초안” 단계에 있는 제안된 DOM 수준 3 API를 기반으로 하지만, 이 특정 인터페이스는 논란의 여지가 없는 것으로 보입니다. W3C의 변경 사항이 파이썬 DOM 인터페이스에서 이 메서드에 반드시 영향을 미치는 것은 아닙니다 (이를 위한 새 W3C API도 지원되기는 하겠지만).

Node.appendChild(newChild)

자식 리스트의 끝에 이 노드의 새 자식 노드를 추가하고, newChild를 반환합니다. 노드가 이미 트리에 있으면, 먼저 제거됩니다.

Node.insertBefore(newChild, refChild)

기존 자식 앞에 새 자식 노드를 삽입합니다. refChild가 이 노드의 자식이어야 합니다; 그렇지 않으면 ValueError가 발생합니다. newChild가 반환됩니다. refChild가 None이면, 자식 리스트의 끝에 newChild를 삽입합니다.

Node.removeChild(oldChild)

자식 노드를 제거합니다. oldChild는 이 노드의 자식이어야 합니다; 그렇지 않으면, ValueError가 발생합니다. 성공하면 oldChild가 반환됩니다. oldChild가 더는 사용되지 않으면, 그것의 unlink() 메서드를 호출해야 합니다.

Node.replaceChild(newChild, oldChild)

기존 노드를 새 노드로 교체합니다. oldChild는 이 노드의 자식이어야 합니다. 그렇지 않으면, ValueError가 발생합니다.

Node.normalize()

모든 텍스트 스트레치(stretch)가 단일 Text 인스턴스로 저장되도록, 인접한 텍스트 노드를 결합합니다. 이는 많은 응용 프로그램에서 DOM 트리의 텍스트 처리를 단순화합니다.

Node.cloneNode(deep)

이 노드를 복제합니다. deep을 설정하면 모든 자식 노드도 복제됩니다. 복제를 반환합니다.

NodeList 객체

NodeList는 노드의 시퀀스를 나타냅니다. 이러한 객체는 DOM Core 권장 사항에서 두 가지 방식으로 사용됩니다: Element 객체는 자식 노드의 리스트를 제공하고, Node의 getElementsByTagName()과 getElementsByTagNameNS() 메서드는 이 인터페이스를 사용하여 조회 결과를 나타냅니다.

DOM 수준 2 권장 사항은 이러한 객체에 대해 하나의 메서드와 하나의 어트리뷰트를 정의합니다:

NodeList.item(i)

시퀀스의 i 번째 항목(있다면)이나 None을 반환합니다. 인덱스 i는 0보다 작거나 시퀀스의 길이보다 크거나 같을 수 없습니다.

NodeList.length

시퀀스의 노드 수.

또한, 파이썬 DOM 인터페이스는 NodeList 객체를 파이썬 시퀀스로 사용할 수 있도록 몇 가지 추가 지원을 요구합니다. 모든 NodeList 구현에는 __len__()과 __getitem__()에 대한 지원이 포함되어야 합니다; 이를 통해 for 문에서 NodeList를 이터레이트할 수 있고, len() 내장 함수를 적절히 지원할 수 있습니다.

DOM 구현이 문서 수정을 지원하면, NodeList 구현은 __setitem__()과 __delitem__() 메서드도 지원해야 합니다.

DocumentType 객체

문서에 의해 선언된 표기법과 엔티티에 대한 정보(구문 분석기가 사용하고 정보를 제공할 수 있으면 외부 부분 집합(external subset)을 포함하는)는 DocumentType 객체에서 사용 가능합니다. 문서의 DocumentType은 Document 객체의 doctype 어트리뷰트에서 사용 가능합니다; 문서에 DOCTYPE 선언이 없으면, 문서의 doctype 어트리뷰트는 이 인터페이스의 인스턴스 대신 None으로 설정됩니다.

DocumentType은 Node의 특수화(specialization)이고 다음 어트리뷰트를 추가합니다:

DocumentType.publicId

문서 형 정의의 외부 부분 집합(external subset)에 대한 공용 식별자. 문자열이나 None입니다.

DocumentType.systemId

문서 형 정의의 외부 부분 집합(external subset)에 대한 시스템 식별자. 문자열로 표현된 URI이거나 None입니다.

DocumentType.internalSubset

문서에서 완전한 내부 부분 집합(internal subset)을 제공하는 문자열. 부분 집합을 묶는 대괄호는 포함되지 않습니다. 문서에 내부 부분 집합이 없으면 None이어야 합니다.

DocumentType.name

DOCTYPE 선언에 제공된 루트 엘리먼트의 이름 (있다면).

DocumentType.entities

외부 엔티티의 정의를 제공하는 NamedNodeMap입니다. 엔티티 이름이 두 번 이상 정의되면, 첫 번째 정의 만 제공됩니다 (XML 권장 사항에 따라 다른 정의는 무시됩니다). 구문 분석기가 정보를 제공하지 않거나 정의된 엔티티가 없으면 None일 수 있습니다.

DocumentType.notations

표기법의 정의를 제공하는 NamedNodeMap입니다. 표기법 이름이 두 번 이상 정의되면, 첫 번째 정의 만 제공됩니다 (XML 권장 사항에 따라 다른 정의는 무시됩니다). 구문 분석기가 정보를 제공하지 않거나 정의된 표기법이 없으면 None일 수 있습니다.

Document 객체

Document는 구성 엘리먼트, 어트리뷰트, 처리 명령어, 주석 등을 포함한 전체 XML 문서를 나타냅니다. Node의 프로퍼티를 상속한다는 점을 기억하십시오.

Document.documentElement

문서의 유일한 루트 엘리먼트.

Document.createElement(tagName)

새 엘리먼트 노드를 만들고 반환합니다. 엘리먼트는 만들어질 때 문서에 삽입되지 않습니다. insertBefore()나 appendChild()와 같은 다른 메서드 중 하나를 사용하여 명시적으로 삽입해야 합니다.

Document.createElementNS(namespaceURI, tagName)

이름 공간을 사용하여 새 엘리먼트를 만들고 반환합니다. tagName은 접두사를 가질 수 있습니다. 엘리먼트는 만들어질 때 문서에 삽입되지 않습니다. insertBefore()나 appendChild()와 같은 다른 메서드 중 하나를 사용하여 명시적으로 삽입해야 합니다.

Document.createTextNode(data)

매개 변수로 전달된 data를 포함하는 텍스트 노드를 만들고 반환합니다. 다른 생성 메서드와 마찬가지로 이 메서드는 노드를 트리에 삽입하지 않습니다.

Document.createComment(data)

매개 변수로 전달된 data를 포함하는 주석 노드를 만들고 반환합니다. 다른 생성 메서드와 마찬가지로 이 메서드는 노드를 트리에 삽입하지 않습니다.

Document.createProcessingInstruction(target, data)

매개 변수로 전달된 target과 data를 포함하는 처리 명령어 노드를 만들고 반환합니다. 다른 생성 메서드와 마찬가지로 이 메서드는 노드를 트리에 삽입하지 않습니다.

Document.createAttribute(name)

어트리뷰트 노드를 만들고 반환합니다. 이 메서드는 어트리뷰틀 노드를 특정 엘리먼트와 연관시키지 않습니다. 새로 만들어진 어트리뷰트 인스턴스를 사용하려면 적절한 Element 객체에서 setAttributeNode()를 사용해야 합니다.

Document.createAttributeNS(namespaceURI, qualifiedName)

이름 공간을 사용하여 어트리뷰트 노드를 만들고 반환합니다. tagName은 접두사를 가질 수 있습니다. 이 메서드는 어트리뷰트 노드를 특정 엘리먼트와 연관시키지 않습니다. 새로 만들어진 어트리뷰트 인스턴스를 사용하려면 적절한 Element 객체에서 setAttributeNode()를 사용해야합니다.

Document.getElementsByTagName(tagName)

특정 엘리먼트 형 이름을 가진 모든 자손(직계 자식, 자식의 자식 등)을 검색합니다.

Document.getElementsByTagNameNS(namespaceURI, localName)

특정 이름 공간 URI와 지역 이름(localname)을 사용하여 모든 자손(직계 자식, 자식의 자식 등)을 검색합니다. 지역 이름은 접두사 다음에 나오는 이름 공간의 일부입니다.

Element 객체

Element는 Node의 서브 클래스이므로, 모든 어트리뷰트를 상속합니다.

Element.tagName

엘리먼트 형 이름. 이름 공간을 사용하는 문서에서는 콜론을 포함할 수 있습니다. 값은 문자열입니다.

Element.getElementsByTagName(tagName)

Document 클래스의 동등한 메서드와 같습니다.

Element.getElementsByTagNameNS(namespaceURI, localName)

Document 클래스의 동등한 메서드와 같습니다.

Element.hasAttribute(name)

엘리먼트에 name이라는 이름의 어트리뷰트가 있으면 True를 반환합니다.

Element.hasAttributeNS(namespaceURI, localName)

엘리먼트에 namespaceURI와 localName으로 이름이 지정된 어트리뷰트가 있으면 True를 반환합니다.

Element.getAttribute(name)

name이라는 이름의 어트리뷰트의 값을 문자열로 반환합니다. 그러한 어트리뷰트가 없으면, 어트리뷰트에 값이 없는 것처럼 빈 문자열이 반환됩니다.

Element.getAttributeNode(attrname)

attrname이라는 이름의 어트리뷰트에 대한 Attr 노드를 반환합니다.

Element.getAttributeNS(namespaceURI, localName)

namespaceURI와 localName으로 이름이 지정된 어트리뷰트의 값을 문자열로 반환합니다. 그러한 어트리뷰트가 없으면, 어트리뷰트에 값이 없는 것처럼 빈 문자열이 반환됩니다.

Element.getAttributeNodeNS(namespaceURI, localName)

namespaceURI와 localName으로 주어진 어트리뷰트의 값을 노드로 반환합니다.

Element.removeAttribute(name)

이름(name)으로 어트리뷰트를 제거합니다. 일치하는 어트리뷰트가 없으면 NotFoundErr가 발생합니다.

Element.removeAttributeNode(oldAttr)

존재하면, 어트리뷰트 목록에서 oldAttr를 제거하고 반환합니다. oldAttr가 없으면 NotFoundErr가 발생합니다.

Element.removeAttributeNS(namespaceURI, localName)

이름으로 어트리뷰트를 제거합니다. qname이 아닌 localName을 사용함에 유의하십시오. 일치하는 어트리뷰트가 없어도 예외가 발생하지 않습니다.

Element.setAttribute(name, value)

문자열로 어트리뷰트 값을 설정합니다.

Element.setAttributeNode(newAttr)

엘리먼트에 새 어트리뷰트 노드를 추가합니다. name 어트리뷰트가 일치할 때 필요하면 기존 어트리뷰트를 대체합니다. 대체가 발생하면, 이전 어트리뷰트 노드가 반환됩니다. newAttr가 이미 사용 중이면 InuseAttributeErr가 발생합니다.

Element.setAttributeNodeNS(newAttr)

엘리먼트에 새 어트리뷰트 노드를 추가합니다. namespaceURI와 localName 어트리뷰트가 일치할 때 필요하면 기존 어트리뷰트를 대체합니다. 대체가 발생하면 이전 어트리뷰트 노드가 반환됩니다. newAttr가 이미 사용 중이면 InuseAttributeErr가 발생합니다.

Element.setAttributeNS(namespaceURI, qname, value)

문자열로 namespaceURI와 qname으로 지정된 어트리뷰트 값을 설정합니다. qname은 전체 어트리뷰트 이름임에 유의하십시오. 이것은 위와 다릅니다.

Attr 객체

Attr은 Node를 상속하므로, 모든 어트리뷰트를 상속합니다.

Attr.name

어트리뷰트 이름. 이름 공간을 사용하는 문서에서는 콜론을 포함할 수 있습니다.

Attr.localName

콜론이 있으면 그 뒤에 오는 이름의 일부, 그렇지 않으면 전체 이름. 이것은 읽기 전용 어트리뷰트입니다.

Attr.prefix

콜론이 있으면 그 앞에 오는 이름의 일부, 그렇지 않으면 빈 문자열.

Attr.value

어트리뷰트의 텍스트 값. 이것은 nodeValue 어트리뷰트의 동의어입니다.

NamedNodeMap 객체

NamedNodeMap은 Node를 상속하지 않습니다.

NamedNodeMap.length

어트리뷰트 목록의 길이입니다.

NamedNodeMap.item(index)

특정 인덱스에 있는 어트리뷰트를 반환합니다. 어트리뷰트를 얻는 순서는 임의적이지만 DOM 수명 동안 일관적입니다. 각 항목은 어트리뷰트 노드입니다. value 어트리뷰트로 값을 얻으십시오.

There are also experimental methods that give this class more mapping behavior. You can use them or you can use the standardized getAttribute*() family of methods on the Element objects.

Comment 객체

Comment는 XML 문서의 주석을 나타냅니다. Node의 서브 클래스이지만, 자식 노드를 가질 수 없습니다.

Comment.data

주석의 내용을 제공하는 문자열. 이 어트리뷰트는 선행 <!--와 후행 --> 사이의 모든 문자를 포함하지만, 이들을 포함하지는 않습니다.

Text와 CDATASection 객체

Text 인터페이스는 XML 문서의 텍스트를 나타냅니다. 구문 분석기와 DOM 구현이 DOM의 XML 확장을 지원하면, CDATA로 표시된 섹션으로 묶인 텍스트 부분은 CDATASection 객체에 저장됩니다. 이 두 인터페이스는 같지만, nodeType 어트리뷰트에서 다른 값을 제공합니다.

이 인터페이스는 Node 인터페이스를 확장합니다. 자식 노드를 가질 수 없습니다.

Text.data

문자열로 표현된 텍스트 노드의 내용.

참고

CDATASection 노드의 사용이 그 노드가 완전한 CDATA 표시 섹션을 표현한다고 나타내는 것은 아닙니다, 단지 노드의 내용이 CDATA 섹션의 일부임을 나타낼 뿐입니다. 단일 CDATA 섹션은 문서 트리에서 둘 이상의 노드로 표현될 수 있습니다. 인접한 두 개의 CDATASection 노드가 다른 CDATA 표시 섹션을 나타내는지를 확인할 방법은 없습니다.

ProcessingInstruction 객체

XML 문서의 처리 명령어를 나타냅니다; 이것은 Node 인터페이스를 상속하며 자식 노드를 가질 수 없습니다.

ProcessingInstruction.target

첫 번째 공백 문자까지의 처리 명령어의 내용. 이것은 읽기 전용 어트리뷰트입니다.

ProcessingInstruction.data

첫 번째 공백 문자 다음에 오는 처리 명령어의 내용.

예외

DOM 수준 2 권장 사항은 단일 예외 DOMException과 응용 프로그램이 어떤 종류의 에러가 발생했는지 판별하도록 하는 여러 상수를 정의합니다. DOMException 인스턴스에는 구체적인 예외에 적절한 값을 제공하는 code 어트리뷰트가 있습니다.

파이썬 DOM 인터페이스는 상수를 제공하지만, 동시에 예외 집합을 확장하여 DOM에 의해 정의된 각 예외 코드마다 구체적인 예외가 존재하도록 합니다. 구현 시 적절한 구체적인 예외를 발생시켜야 하며, 각 예외는 code 속성으로 적절한 값을 제공합니다.

exception xml.dom.DOMException

모든 구체적인 DOM 예외에 사용되는 베이스 예외 클래스. 이 예외 클래스는 직접 인스턴스 화할 수 없습니다.

exception xml.dom.DomstringSizeErr

지정된 텍스트 범위가 문자열에 맞지 않을 때 발생합니다. 이것은 파이썬 DOM 구현에서 사용되는 것으로 알려지지 않았지만, 파이썬으로 작성되지 않은 DOM 구현에서 수신될 수 있습니다.

exception xml.dom.HierarchyRequestErr

노드 형이 허용하지 않는 곳에 노드를 삽입하려고 할 때 발생합니다.

exception xml.dom.IndexSizeErr

메서드의 인덱스(index)나 크기(size) 매개 변수가 음수이거나 허용된 값을 초과할 때 발생합니다.

exception xml.dom.InuseAttributeErr

문서의 다른 곳에 이미 존재하는 Attr 노드를 삽입하려고 할 때 발생합니다.

exception xml.dom.InvalidAccessErr

하부 객체에서 매개 변수나 연산이 지원되지 않으면 발생합니다.

exception xml.dom.InvalidCharacterErr

이 예외는 문자열 매개 변수에 XML 1.0 권장 사항에서 사용 중인 컨텍스트에서 허용되지 않는 문자가 포함될 때 발생합니다. 예를 들어, 엘리먼트 형 이름에 스페이스가 있는 Element 노드를 만들려고 하면 이 에러가 발생합니다.

exception xml.dom.InvalidModificationErr

노드 형을 수정하려고 할 때 발생합니다.

exception xml.dom.InvalidStateErr

정의되지 않았거나 더는 사용할 수 없는 객체를 사용하려고 할 때 발생합니다.

exception xml.dom.NamespaceErr

Namespaces in XML [https://www.w3.org/TR/REC-xml-names/] 권장 사항에서 허용되지 않는 방식으로 객체를 변경하려고 시도하면 이 예외가 발생합니다.

exception xml.dom.NotFoundErr

참조된 컨텍스트에 노드가 존재하지 않을 때 발생하는 예외. 예를 들어, NamedNodeMap.removeNamedItem()은 전달된 노드가 맵에 존재하지 않으면 이것을 발생시킵니다.

exception xml.dom.NotSupportedErr

구현이 요청된 형의 객체나 연산을 지원하지 않을 때 발생합니다.

exception xml.dom.NoDataAllowedErr

데이터를 지원하지 않는 노드에 데이터가 지정되면 발생합니다.

exception xml.dom.NoModificationAllowedErr

수정이 허용되지 않는 객체(가령 읽기 전용 노드)를 수정하려고 하면 발생합니다.

exception xml.dom.SyntaxErr

유효하지 않거나 잘못된 문자열이 지정될 때 발생합니다.

exception xml.dom.WrongDocumentErr

노드가 현재 속한 것과 다른 문서에 삽입되고 구현이 한 문서에서 다른 문서로 노드 이전을 지원하지 않을 때 발생합니다.

DOM 권장 사항에 정의된 예외 코드는 이 테이블에 따라 위에서 설명한 예외에 매핑됩니다:

상수

예외

DOMSTRING_SIZE_ERR

DomstringSizeErr

HIERARCHY_REQUEST_ERR

HierarchyRequestErr

INDEX_SIZE_ERR

IndexSizeErr

INUSE_ATTRIBUTE_ERR

InuseAttributeErr

INVALID_ACCESS_ERR

InvalidAccessErr

INVALID_CHARACTER_ERR

InvalidCharacterErr

INVALID_MODIFICATION_ERR

InvalidModificationErr

INVALID_STATE_ERR

InvalidStateErr

NAMESPACE_ERR

NamespaceErr

NOT_FOUND_ERR

NotFoundErr

NOT_SUPPORTED_ERR

NotSupportedErr

NO_DATA_ALLOWED_ERR

NoDataAllowedErr

NO_MODIFICATION_ALLOWED_ERR

NoModificationAllowedErr

SYNTAX_ERR

SyntaxErr

WRONG_DOCUMENT_ERR

WrongDocumentErr

규격 준수

이 섹션에서는 규격 준수 요구 사항과 파이썬 DOM API, W3C DOM 권장 사항 및 파이썬의 OMG IDL 매핑 간의 관계에 관해 설명합니다.

형 매핑

DOM 명세에 사용된 IDL 형은 다음 표에 따라 파이썬 형에 매핑됩니다.

IDL 형

파이썬 형

boolean

bool 또는 int

int

int

long int

int

unsigned int

int

DOMString

str 또는 bytes

null

None

접근자 메서드

OMG IDL에서 파이썬으로의 매핑은 Java 매핑과 거의 같은 방식으로 IDL attribute 선언에 대한 접근자 함수를 정의합니다. 다음과 같은 IDL 선언 매핑은:

readonly attribute string someValue;
         attribute string anotherValue;

세 개의 접근자 함수를 산출합니다: someValue를 위한 “get” 메서드(_get_someValue())와 anotherValue를 위한 “get”과 “set” 메서드(_get_anotherValue()와 _set_anotherValue()). 특히, 매핑은 IDL 어트리뷰트가 일반 파이썬 어트리뷰트로 액세스할 수 있도록 요구하지 않습니다: object.someValue는 작동할 필요 없으며, AttributeError를 발생시킬 수 있습니다.

그러나, 파이썬 DOM API는 일반 어트리뷰트 액세스가 동작하도록 요구합니다. 이것은 파이썬 IDL 컴파일러에 의해 생성된 일반적인 서로게이트가 작동하지 않을 수 있으며, DOM 객체가 CORBA를 통해 액세스되는 경우 래퍼 객체가 클라이언트에 필요할 수 있음을 의미합니다. CORBA DOM 클라이언트에 대해 추가적인 고려가 필요하지만, 파이썬에서 CORBA를 통해 DOM을 사용한 경험이 있는 구현자들은 이것을 문제라고 보지 않습니다. readonly로 선언된 어트리뷰트는 모든 DOM 구현에서 쓰기 액세스를 제한하지 않을 수 있습니다.

파이썬 DOM API에서는, 접근자 함수가 필요하지 않습니다. 제공되면, 파이썬 IDL 매핑으로 정의된 형식을 취해야 하지만, 어트리뷰트를 파이썬에서 직접 액세스할 수 있어서 이러한 메서드들은 불필요한 것으로 간주합니다. readonly 어트리뷰트에 “set” 접근자를 제공해서는 안 됩니다.

IDL 정의는 W3C DOM API의 요구 사항을 완전히 담지 않습니다. 가령 getElementsByTagName()의 반환 값과 같은 특정 객체가 “살아있다(live)”는 개념과 같은 것을 표현하지 못합니다. 파이썬 DOM API는 구현이 이러한 요구 사항을 강제하도록 요구하지 않습니다.

xml.dom.minidom — Minimal DOM implementation

소스 코드: Lib/xml/dom/minidom.py [https://github.com/python/cpython/tree/main/Lib/xml/dom/minidom.py]

xml.dom.minidom은 다른 언어와 유사한 API를 갖는 문서 객체 모델 인터페이스의 최소 구현입니다. 전체(full) DOM보다 단순하고 훨씬 작고자 합니다. DOM에 아직 능숙하지 않은 사용자는 XML 처리에 대신 xml.etree.ElementTree 모듈을 사용하는 것을 고려해야 합니다.

경고

xml.dom.minidom 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점를 참조하십시오.

DOM 응용 프로그램은 일반적으로 일부 XML을 DOM으로 구문 분석하는 것으로 시작합니다. xml.dom.minidom에서는, 구문 분석 함수를 통해 수행됩니다:

from xml.dom.minidom import parse, parseString

dom1 = parse('c:\\temp\\mydata.xml')  # parse an XML file by name

datasource = open('c:\\temp\\mydata.xml')
dom2 = parse(datasource)  # parse an open file

dom3 = parseString('<myxml>Some data<empty/> some more data</myxml>')

parse() 함수는 파일명이나 열린 파일 객체를 취할 수 있습니다.

xml.dom.minidom.parse(filename_or_file, parser=None, bufsize=None)

주어진 입력에서 Document를 반환합니다. filename_or_file은 파일명이나 파일류 객체일 수 있습니다. 제공되면, parser는 SAX2 구문 분석기 객체여야 합니다. 이 함수는 구문 분석기의 문서 처리기를 변경하고 이름 공간 지원을 활성화합니다; 다른 구문 분석기 구성(엔티티 해석기 설정과 같은)은 미리 수행되어 있어야 합니다.

문자열로 XML을 갖고 있다면, parseString() 함수를 대신 사용할 수 있습니다:

xml.dom.minidom.parseString(string, parser=None)

string을 표현하는 Document를 반환합니다. 이 메서드는 문자열에 대한 io.StringIO 객체를 만들고 이를 parse()에 전달합니다.

두 함수 모두 문서의 내용을 표현하는 Document 객체를 반환합니다.

parse()와 parseString() 함수가 하는 일은 임의의 SAX 구문 분석기에서 구문 분석 이벤트를 받아들일 수 있고 이를 DOM 트리로 변환하는 “DOM 구축기(builder)”를 XML 구문 분석기와 연결하는 것입니다. 함수의 이름은 오해의 소지가 있지만, 인터페이스를 배울 때 이해하기 쉽습니다. 이 함수가 반환되기 전에 문서 구문 분석이 완료됩니다; 단지 이 함수들이 구문 분석기 구현 자체를 제공하지는 않을 뿐입니다.

“DOM 구현” 객체의 메서드를 호출하여 Document를 만들 수도 있습니다. xml.dom 패키지나 xml.dom.minidom 모듈에 있는 getDOMImplementation() 함수를 호출하여 이 객체를 얻을 수 있습니다. 일단 Document를 얻으면, 자식 노드를 추가하여 DOM을 채울 수 있습니다:

from xml.dom.minidom import getDOMImplementation

impl = getDOMImplementation()

newdoc = impl.createDocument(None, "some_tag", None)
top_element = newdoc.documentElement
text = newdoc.createTextNode('Some textual content.')
top_element.appendChild(text)

일단 DOM 문서 객체를 얻으면, 프로퍼티와 메서드를 통해 XML 문서의 일부에 액세스 할 수 있습니다. 이러한 프로퍼티들은 DOM 명세에 정의되어 있습니다. 문서 객체의 주 프로퍼티는 documentElement 프로퍼티입니다. XML 문서의 메인 엘리먼트를 제공합니다: 모든 다른 것들을 담는 것. 예제 프로그램은 다음과 같습니다:

dom3 = parseString("<myxml>Some data</myxml>")
assert dom3.documentElement.tagName == "myxml"

When you are finished with a DOM tree, you may optionally call the unlink() method to encourage early cleanup of the now-unneeded objects. unlink() is an xml.dom.minidom-specific extension to the DOM API that renders the node and its descendants essentially useless. Otherwise, Python’s garbage collector will eventually take care of the objects in the tree.

더 보기

Document Object Model (DOM) Level 1 Specification [https://www.w3.org/TR/REC-DOM-Level-1/]

xml.dom.minidom이 지원하는 DOM에 대한 W3C 권장 사항.

DOM 객체

파이썬 용 DOM API의 정의는 xml.dom 모듈 설명서의 일부로 제공됩니다. 이 절은 그 API와 xml.dom.minidom의 차이점을 나열합니다.

Node.unlink()

순환 GC가 없는 파이썬 버전에서 가비지 수집되도록 DOM 내의 내부 참조를 끊습니다. 순환 GC를 사용할 수 있더라도, 이를 사용하면 대량의 메모리를 더 빨리 사용할 수 있도록 하므로, 더 필요 없게 되는 즉시 DOM 객체에 대해 이를 호출하는 것이 좋습니다. Document 객체에서만 호출하면 되지만, 해당 노드의 자식을 삭제하기 위해 자식 노드에서 호출할 수 있습니다.

with 문을 사용하면 이 메서드를 명시적으로 호출하지 않아도 됩니다. 다음 코드는 with 블록이 종료될 때 dom을 자동으로 unlink 합니다:

with xml.dom.minidom.parse(datasource) as dom:
    ... # Work with dom.

Node.writexml(writer, indent='', addindent='', newl='', encoding=None, standalone=None)

기록기(writer) 객체에 XML을 씁니다. 기록기는 입력으로 텍스트를 받지만 바이트열은 받지 않습니다, 파일 객체 인터페이스와 일치하는 write() 메서드를 가져야 합니다. indent 매개 변수는 현재 노드의 들여쓰기입니다. addindent 매개 변수는 현재 노드의 서브 노드에 사용할 증분(incremental) 들여쓰기입니다. newl 매개 변수는 개행을 끝내는 데 사용할 문자열을 지정합니다.

Document 노드의 경우, 추가 키워드 인자 encoding을 사용하여 XML 헤더의 인코딩 필드를 지정할 수 있습니다.

Similarly, explicitly stating the standalone argument causes the standalone document declarations to be added to the prologue of the XML document. If the value is set to True, standalone="yes" is added, otherwise it is set to "no". Not stating the argument will omit the declaration from the document.

버전 3.8에서 변경: writexml() 메서드는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

버전 3.9에서 변경: The standalone parameter was added.

Node.toxml(encoding=None, standalone=None)

DOM 노드가 나타내는 XML이 포함된 문자열이나 바이트열을 반환합니다.

명시적인 encoding [1] 인자를 사용하면, 결과는 지정된 인코딩의 바이트열 입니다. encoding 인자가 없으면, 결과는 유니코드 문자열이며, 결과 문자열의 XML 선언은 인코딩을 지정하지 않습니다. UTF-8이 XML의 기본 인코딩이기 때문에, UTF-8 이외의 인코딩으로 이 문자열을 인코딩하는 것은 올바르지 않습니다.

standalone 인자는 writexml()에서와 동일하게 동작합니다.

버전 3.8에서 변경: toxml() 메서드는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

버전 3.9에서 변경: The standalone parameter was added.

Node.toprettyxml(indent='\t', newl='\n', encoding=None, standalone=None)

문서의 예쁘게 인쇄된 버전을 반환합니다. indent는 들여쓰기 문자열을 지정하고 기본값은 탭입니다; newl은 각 줄의 끝에서 방출되는 문자열을 지정하고 기본값은 \n입니다.

encoding 인자는 toxml()의 해당 인자처럼 동작합니다.

standalone 인자는 writexml()에서와 동일하게 동작합니다.

버전 3.8에서 변경: toprettyxml() 메서드는 이제 사용자가 지정한 어트리뷰트 순서를 유지합니다.

버전 3.9에서 변경: The standalone parameter was added.

DOM 예제

이 예제 프로그램은 간단한 프로그램의 상당히 현실적인 예입니다. 이 특별한 경우에, 우리는 DOM의 유연성을 크게 활용하지 않습니다.

import xml.dom.minidom

document = """\
<slideshow>
<title>Demo slideshow</title>
<slide><title>Slide title</title>
<point>This is a demo</point>
<point>Of a program for processing slides</point>
</slide>

<slide><title>Another demo slide</title>
<point>It is important</point>
<point>To have more than</point>
<point>one slide</point>
</slide>
</slideshow>
"""

dom = xml.dom.minidom.parseString(document)

def getText(nodelist):
    rc = []
    for node in nodelist:
        if node.nodeType == node.TEXT_NODE:
            rc.append(node.data)
    return ''.join(rc)

def handleSlideshow(slideshow):
    print("<html>")
    handleSlideshowTitle(slideshow.getElementsByTagName("title")[0])
    slides = slideshow.getElementsByTagName("slide")
    handleToc(slides)
    handleSlides(slides)
    print("</html>")

def handleSlides(slides):
    for slide in slides:
        handleSlide(slide)

def handleSlide(slide):
    handleSlideTitle(slide.getElementsByTagName("title")[0])
    handlePoints(slide.getElementsByTagName("point"))

def handleSlideshowTitle(title):
    print(f"<title>{getText(title.childNodes)}</title>")

def handleSlideTitle(title):
    print(f"<h2>{getText(title.childNodes)}</h2>")

def handlePoints(points):
    print("<ul>")
    for point in points:
        handlePoint(point)
    print("</ul>")

def handlePoint(point):
    print(f"<li>{getText(point.childNodes)}</li>")

def handleToc(slides):
    for slide in slides:
        title = slide.getElementsByTagName("title")[0]
        print(f"<p>{getText(title.childNodes)}</p>")

handleSlideshow(dom)

minidom과 DOM 표준

xml.dom.minidom 모듈은 본질적으로 일부 DOM 2 기능(주로 이름 공간 기능)이 있는 DOM 1.0 호환 DOM입니다.

파이썬에서 DOM 인터페이스의 사용법은 간단합니다. 다음과 같은 매핑 규칙이 적용됩니다:

인터페이스는 인스턴스 객체를 통해 액세스 됩니다. 응용 프로그램은 클래스를 직접 인스턴스로 만들어서는 안 됩니다; Document 객체에서 제공되는 생성자 함수를 사용해야 합니다. 파생 인터페이스는 베이스 인터페이스의 모든 연산(및 어트리뷰트)과 새로운 연산을 지원합니다.

연산은 메서드로 사용됩니다. DOM은 in 매개 변수만 사용하므로, 인자는 정상적인 순서(왼쪽에서 오른쪽으로)로 전달됩니다. 선택적 인자가 없습니다. void 연산은 None을 반환합니다.

IDL 어트리뷰트는 인스턴스 어트리뷰트에 매핑됩니다. 파이썬 용 OMG IDL 언어 매핑과의 호환성을 위해, 접근자 메서드 _get_foo()와 _set_foo()를 통해 어트리뷰트 foo에 액세스할 수도 있습니다. readonly 어트리뷰트는 변경하지 않아야 합니다; 실행 시간에 강제되지는 않습니다.

short int, unsigned int, unsigned long long 및 boolean 형은 모두 파이썬 정수 객체에 매핑됩니다.

DOMString 형은 파이썬 문자열에 매핑됩니다. xml.dom.minidom은 바이트열이나 문자열을 지원하지만, 일반적으로 문자열을 생성합니다. DOMString 형의 값은 W3C의 DOM 명세에 의해 IDL null 값을 가질 수 있을 때 None일 수도 있습니다.

const 선언은 해당 스코프에 있는 변수에 매핑됩니다 (예를 들어 xml.dom.minidom.Node.PROCESSING_INSTRUCTION_NODE); 변경되지 않아야 합니다.

DOMException은 현재 xml.dom.minidom에서 지원되지 않습니다. 대신, xml.dom.minidom은 TypeError와 AttributeError와 같은 표준 파이썬 예외를 사용합니다.

NodeList 객체는 파이썬의 내장 리스트 형을 사용하여 구현됩니다. 이러한 객체는 DOM 명세에 정의된 인터페이스를 제공하지만, 이전 버전의 파이썬에서는 공식 API를 지원하지 않습니다. 그러나 W3C 권장 사항에 정의된 인터페이스보다 훨씬 “파이썬답습니다”.

다음 인터페이스는 xml.dom.minidom에서 구현되지 않습니다:

DOMTimeStamp

EntityReference

이들 대부분은 대부분의 DOM 사용자에게 일반적인 쓸모를 제공하지 않는 XML 문서의 정보를 반영합니다.

각주

[1]

XML 출력에 포함된 인코딩 이름은 적절한 표준을 준수해야 합니다. 예를 들어, XML 문서의 선언에서 “UTF-8”은 유효하지만, “UTF8”은 파이썬이 이를 인코딩 이름으로 받아들이더라도 유효하지 않습니다. https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl 과 https://www.iana.org/assignments/character-sets/character-sets.xhtml 을 참조하십시오.

xml.dom.pulldom — Support for building partial DOM trees

소스 코드: Lib/xml/dom/pulldom.py [https://github.com/python/cpython/tree/main/Lib/xml/dom/pulldom.py]

xml.dom.pulldom 모듈은 필요할 때 문서의 DOM 액세스 가능한 조각을 생성하도록 요청할 수 있는 “풀 구문 분석기 (pull parser)”를 제공합니다. 기본 개념은 들어오는 XML 스트림에서 “이벤트”를 끌어당겨서(pull) 처리하는 것입니다. 콜백을 통한 이벤트 구동 처리 모델(event-driven processing model)을 사용하는 SAX와 달리 풀 구문 분석기 사용자는 스트림에서 이벤트를 명시적으로 가져와서 처리가 완료되거나 에러 조건이 발생할 때까지 그 이벤트들을 루핑해야 합니다.

경고

xml.dom.pulldom 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점를 참조하십시오.

버전 3.7.1에서 변경: SAX 구문 분석기는 보안을 강화하기 위해 더는 일반 외부 엔티티를 처리하지 않습니다. 외부 엔티티를 처리를 활성화하려면, 사용자 정의 구문 분석기 인스턴스를 전달하십시오:

from xml.dom.pulldom import parse
from xml.sax import make_parser
from xml.sax.handler import feature_external_ges

parser = make_parser()
parser.setFeature(feature_external_ges, True)
parse(filename, parser=parser)

예:

from xml.dom import pulldom

doc = pulldom.parse('sales_items.xml')
for event, node in doc:
    if event == pulldom.START_ELEMENT and node.tagName == 'item':
        if int(node.getAttribute('price')) > 50:
            doc.expandNode(node)
            print(node.toxml())

event는 상수이며 다음 중 하나일 수 있습니다:

START_ELEMENT

END_ELEMENT

COMMENT

START_DOCUMENT

END_DOCUMENT

CHARACTERS

PROCESSING_INSTRUCTION

IGNORABLE_WHITESPACE

node는 xml.dom.minidom.Document, xml.dom.minidom.Element 또는 xml.dom.minidom.Text 형의 객체입니다.

문서는 “평평한(flat)” 이벤트 스트림으로 취급되므로, 문서 “트리”는 묵시적으로 탐색 되며 트리에서의 깊이와 관계없이 원하는 요소를 찾습니다. 다시 말해, 문서 노드의 재귀적 검색과 같은 계층적 문제를 고려할 필요는 없습니다. 하지만, 엘리먼트의 문맥이 중요하다면, 문맥과 관련된 상태를 유지하거나 (즉, 주어진 지점에서 문서의 어느 위치에 있는지 기억함으로써), DOMEventStream.expandNode() 메서드를 사용하고 DOM 관련 처리로 전환해야 합니다.

class xml.dom.pulldom.PullDom(documentFactory=None)

xml.sax.handler.ContentHandler의 서브 클래스.

class xml.dom.pulldom.SAX2DOM(documentFactory=None)

xml.sax.handler.ContentHandler의 서브 클래스.

xml.dom.pulldom.parse(stream_or_string, parser=None, bufsize=None)

주어진 입력으로부터 DOMEventStream을 반환합니다. stream_or_string은 파일 이름이거나 파일류 객체일 수 있습니다. 주어질 때, parser는 XMLReader 객체여야 합니다. 이 함수는 구문 분석기의 문서 처리기를 변경하고 이름 공간 지원을 활성화합니다; 다른 구문 분석기 구성(엔티티 해석기 설정과 같은)은 미리 수행되어 있어야 합니다.

문자열로 XML을 갖고 있다면, parseString() 함수를 대신 사용할 수 있습니다:

xml.dom.pulldom.parseString(string, parser=None)

(유니코드) string을 표현하는 DOMEventStream을 반환합니다.

xml.dom.pulldom.default_bufsize

parse()의 bufsize 매개 변수의 기본값.

이 변수의 값은 parse()를 호출하기 전에 변경될 수 있으며 새 값이 적용됩니다.

DOMEventStream 객체

class xml.dom.pulldom.DOMEventStream(stream, parser, bufsize)

버전 3.11에서 변경: Support for __getitem__() method has been removed.

getEvent()

event와 현재 node를 포함하는 튜플을 반환합니다. 노드는 이벤트가 START_DOCUMENT와 같으면 xml.dom.minidom.Document, 이벤트가 START_ELEMENT나 END_ELEMENT와 같으면 xml.dom.minidom.Element, 이벤트가 CHARACTERS와 같으면 xml.dom.minidom.Text 입니다. expandNode()가 호출되지 않는 한 현재 노드에는 자식에 대한 정보가 없습니다.

expandNode(node)

node의 모든 자식을 node로 확장합니다. 예:

from xml.dom import pulldom

xml = '<html><title>Foo</title> <p>Some text <div>and more</div></p> </html>'
doc = pulldom.parseString(xml)
for event, node in doc:
    if event == pulldom.START_ELEMENT and node.tagName == 'p':
        # Following statement only prints '<p/>'
        print(node.toxml())
        doc.expandNode(node)
        # Following statement prints node with all its children '<p>Some text <div>and more</div></p>'
        print(node.toxml())

reset()

xml.sax — Support for SAX2 parsers

소스 코드: Lib/xml/sax/__init__.py [https://github.com/python/cpython/tree/main/Lib/xml/sax/__init__.py]

xml.sax 패키지는 파이썬용 SAX(Simple API for XML) 인터페이스를 구현하는 여러 모듈을 제공합니다. 패키지 자체는 대부분 SAX API의 사용자가 사용하게 될 SAX 예외와 편리 함수를 제공합니다.

경고

xml.sax 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점을 참조하십시오.

버전 3.7.1에서 변경: SAX 구문 분석기는 보안을 강화하기 위해 더는 일반 외부 엔티티를 처리하지 않습니다. 이전에는, 구문 분석기가 DTD와 엔티티에 대해 네트워크 연결을 만들어 원격 파일을 가져오거나 파일 시스템에서 로컬 파일을 로드했습니다. 이 기능은 구문 분석기 객체에 대해 인자 feature_external_ges로 메서드 setFeature()를 사용하여 다시 활성화할 수 있습니다.

편리 함수는 다음과 같습니다:

xml.sax.make_parser(parser_list=[])

SAX XMLReader 객체를 만들고 반환합니다. 발견된 첫 번째 구문 분석기가 사용됩니다. parser_list가 제공되면, create_parser()라는 함수가 있는 모듈의 이름을 나타내는 문자열의 이터러블이어야 합니다. parser_list에 나열된 모듈은 기본 구문 분석기 목록에 있는 모듈보다 먼저 사용됩니다.

버전 3.8에서 변경: parser_list 인자는 리스트뿐만 아니라 임의의 이터러블일 수 있습니다.

xml.sax.parse(filename_or_stream, handler, error_handler=handler.ErrorHandler())

SAX 구문 분석기를 만들어 문서 구문 분석에 사용합니다. filename_or_stream으로 전달된 문서는 파일명이나 파일 객체일 수 있습니다. handler 매개 변수는 SAX ContentHandler 인스턴스여야 합니다. error_handler가 주어지면, SAX ErrorHandler 인스턴스여야 합니다; 생략하면, 모든 에러에서 SAXParseException이 발생합니다. 반환 값은 없습니다; 모든 작업은 전달된 handler가 처리해야 합니다.

xml.sax.parseString(string, handler, error_handler=handler.ErrorHandler())

parse()와 비슷하지만, 매개 변수로 받은 버퍼 string에서 구문 분석합니다. string은 str 인스턴스나 바이트열류 객체여야 합니다.

버전 3.5에서 변경: str 인스턴스에 대한 지원이 추가되었습니다.

전형적인 SAX 응용 프로그램은 입력기(reader), 처리기(handler) 및 입력 소스(input source)의 세 가지 종류의 객체를 사용합니다: 이 문맥에서 “입력기(Reader)”는 구문 분석기에 대한 또 다른 용어입니다, 즉, 입력 소스에서 바이트나 문자를 읽고, 이벤트 시퀀스를 생성하는 코드 조각입니다. 그런 다음 이벤트는 처리기 객체로 배포됩니다, 즉 입력기가 처리기의 메서드를 호출합니다. 따라서 SAX 응용 프로그램은 입력기 객체를 얻고, 입력 소스를 만들거나 열고, 처리기를 만들고, 이 객체들을 모두 연결해야 합니다. 준비의 마지막 단계로, 입력기가 입력을 구문 분석하도록 호출됩니다. 구문 분석하는 동안, 처리기 객체의 메서드는 입력 데이터로부터 온 구조적 및 구문적 이벤트를 기반으로 호출됩니다.

이러한 객체들은, 인터페이스만 중요합니다; 그들은 일반적으로 응용 프로그램 자체에 의해 인스턴스로 만들어지지 않습니다. 파이썬에는 인터페이스에 대한 명시적인 개념이 없으므로, 이것들이 형식적으로는 클래스로 소개되지만, 응용 프로그램은 제공된 클래스를 상속하지 않는 구현을 사용할 수 있습니다. InputSource, Locator, Attributes, AttributesNS 및 XMLReader 인터페이스는 모듈 xml.sax.xmlreader에 정의되어 있습니다. 처리기 인터페이스는 xml.sax.handler에 정의되어 있습니다. 편의상, InputSource(종종 직접 인스턴스를 만듭니다)와 처리기 클래스들은 xml.sax에서도 사용할 수 있습니다. 이러한 인터페이스는 아래에 설명되어 있습니다.

이러한 클래스 외에도, xml.sax는 다음과 같은 예외 클래스를 제공합니다.

exception xml.sax.SAXException(msg, exception=None)

XML 에러나 경고를 캡슐화합니다. 이 클래스에는 XML 구문 분석기나 응용 프로그램의 기본 에러나 경고 정보가 포함될 수 있습니다: 추가 기능을 제공하거나 지역화를 추가하기 위해 서브 클래싱 될 수 있습니다. ErrorHandler 인터페이스에 정의된 처리기가 이 예외의 인스턴스를 수신하지만, 예외를 실제로 발생시킬 필요는 없음에 유의하십시오 — 정보를 담는 컨테이너로도 유용합니다.

인스턴스로 만들어질 때, msg는 사람이 읽을 수 있는 에러에 관한 설명이어야 합니다. 선택적 exception 매개 변수를 주면, None이거나 구문 분석 코드에 의해 잡힌 예외여야 하고, 정보로 함께 전달됩니다.

이것은 다른 SAX 예외 클래스의 베이스 클래스입니다.

exception xml.sax.SAXParseException(msg, exception, locator)

구문 분석 에러 시 발생하는 SAXException의 서브 클래스. 이 클래스의 인스턴스는 SAX ErrorHandler 인터페이스의 메서드에 전달되어 구문 분석 에러에 대한 정보를 제공합니다. 이 클래스는 SAXException 인터페이스뿐만 아니라 SAX Locator 인터페이스를 지원합니다.

exception xml.sax.SAXNotRecognizedException(msg, exception=None)

SAX XMLReader가 인식할 수 없는 기능이나 속성을 만날 때 발생하는 SAXException의 서브 클래스. SAX 응용 프로그램과 확장은 유사한 목적으로 이 클래스를 사용할 수 있습니다.

exception xml.sax.SAXNotSupportedException(msg, exception=None)

SAX XMLReader가 지원되지 않는 기능을 활성화하거나 구현에서 지원하지 않는 값으로 속성을 설정하도록 요청될 때 발생하는 SAXException의 서브 클래스. SAX 응용 프로그램과 확장은 유사한 목적으로 이 클래스를 사용할 수 있습니다.

더 보기

SAX: The Simple API for XML [http://www.saxproject.org/]

이 사이트는 SAX API의 정의가 집중되는 곳입니다. Java 구현과 온라인 설명서를 제공합니다. 구현과 역사적 정보에 대한 링크도 있습니다.

모듈 xml.sax.handler

응용 프로그램이 제공하는 객체에 대한 인터페이스의 정의.

모듈 xml.sax.saxutils

SAX 응용 프로그램에서 사용하기 위한 편리 함수.

모듈 xml.sax.xmlreader

구문 분석기가 제공하는 객체에 대한 인터페이스의 정의.

SAXException 객체

SAXException 예외 클래스는 다음 메서드를 지원합니다:

SAXException.getMessage()

에러 상태를 설명하는 사람이 읽을 수 있는 메시지를 반환합니다.

SAXException.getException()

캡슐화된 예외 객체나 None을 반환합니다.

xml.sax.handler — Base classes for SAX handlers

소스 코드: Lib/xml/sax/handler.py [https://github.com/python/cpython/tree/main/Lib/xml/sax/handler.py]

The SAX API defines five kinds of handlers: content handlers, DTD handlers, error handlers, entity resolvers and lexical handlers. Applications normally only need to implement those interfaces whose events they are interested in; they can implement the interfaces in a single object or in multiple objects. Handler implementations should inherit from the base classes provided in the module xml.sax.handler, so that all methods get default implementations.

class xml.sax.handler.ContentHandler

이것은 SAX의 주 콜백 인터페이스이며, 응용 프로그램에 가장 중요한 인터페이스입니다. 이 인터페이스의 이벤트 순서는 문서에서의 정보 순서를 반영합니다.

class xml.sax.handler.DTDHandler

DTD 이벤트를 처리합니다.

이 인터페이스는 기본 구문 분석에 필요한 DTD 이벤트만 지정합니다 (구문 분석되지 않은 엔티티와 어트리뷰트).

class xml.sax.handler.EntityResolver

엔티티 해석을 위한 기본 인터페이스. 이 인터페이스를 구현하는 객체를 만든 후 구문 분석기에 객체를 등록하면, 구문 분석기는 객체의 메서드를 호출하여 모든 외부 엔티티를 해석합니다.

class xml.sax.handler.ErrorHandler

응용 프로그램에 에러와 경고 메시지를 표시하기 위해 구문 분석기에서 사용하는 인터페이스. 이 객체의 메서드는 에러가 즉시 예외로 변환되는지 또는 다른 방식으로 처리되는지를 제어합니다.

class xml.sax.handler.LexicalHandler

Interface used by the parser to represent low frequency events which may not be of interest to many applications.

이러한 클래스 외에도, xml.sax.handler는 기능과 속성 이름에 대한 기호 상수를 제공합니다.

xml.sax.handler.feature_namespaces

값: "http://xml.org/sax/features/namespaces"

참: 이름 공간 처리를 수행합니다.

거짓: 선택적으로 이름 공간 처리를 수행하지 않습니다 (namespace-prefixes를 암시합니다; 기본값).

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.feature_namespace_prefixes

값: "http://xml.org/sax/features/namespace-prefixes"

참: 이름 공간 선언에 사용된 원래 접두사 이름과 어트리뷰트를 보고합니다.

거짓: 이름 공간 선언에 사용된 어트리뷰트를 보고하지 않고, 선택적으로 원래 접두사 이름을 보고하지 않습니다 (기본값).

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.feature_string_interning

값: "http://xml.org/sax/features/string-interning"

참: 모든 엘리먼트 이름, 접두사, 어트리뷰트 이름, 이름 공간 URI 및 지역 이름은 내장 intern 함수를 사용하여 인턴 됩니다.

거짓: 그럴 수 있지만, 이름이 반드시 인턴 될 필요는 없습니다 (기본값).

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.feature_validation

값: "http://xml.org/sax/features/validation"

참: 모든 유효성 검사 에러를 보고합니다 (external-general-entities와 external-parameter-entities를 암시합니다).

거짓: 유효성 검사 에러를 보고하지 않습니다.

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.feature_external_ges

값: "http://xml.org/sax/features/external-general-entities"

참: 모든 외부 일반 (텍스트) 엔티티를 포함합니다.

거짓: 외부 일반 엔티티를 포함하지 않습니다.

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.feature_external_pes

값: "http://xml.org/sax/features/external-parameter-entities"

참: 외부 DTD 서브 세트를 포함하여, 모든 외부 파라미터 엔티티를 포함합니다.

거짓: 외부 DTD 서브 세트를 포함하여, 어떤 외부 파라미터 엔티티도 포함하지 않습니다.

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.all_features

모든 기능 리스트.

xml.sax.handler.property_lexical_handler

값: "http://xml.org/sax/properties/lexical-handler"

data type: xml.sax.handler.LexicalHandler (not supported in Python 2)

설명: 주석과 같은 어휘 이벤트에 대한 선택적 확장 처리기.

액세스: 읽기/쓰기

xml.sax.handler.property_declaration_handler

값: "http://xml.org/sax/properties/declaration-handler"

데이터형: xml.sax.sax2lib.DeclHandler (파이썬 2에서는 지원되지 않습니다)

설명: 표기법과 구문 분석되지 않은 엔티티 이외의 DTD 관련 이벤트에 대한 선택적 확장 처리기.

액세스: 읽기/쓰기

xml.sax.handler.property_dom_node

값: "http://xml.org/sax/properties/dom-node"

데이터형: org.w3c.dom.Node (파이썬 2에서는 지원되지 않습니다)

설명: 구문 분석할 때, 이것이 DOM 이터레이터이면 방문 중인 현재 DOM 노드; 구문 분석하지 않을 때, 이터레이션을 위한 루트 DOM 노드.

액세스: (구문 분석) 읽기 전용; (구문 분석하지 않음) 읽기/쓰기

xml.sax.handler.property_xml_string

값: "http://xml.org/sax/properties/xml-string"

data type: Bytes

설명: 현재 이벤트의 소스인 리터럴 문자열.

액세스: 읽기 전용

xml.sax.handler.all_properties

알려진 모든 속성 이름 리스트

ContentHandler 객체

사용자는 자신의 응용 프로그램을 지원하기 위해 ContentHandler를 서브 클래싱 할 것으로 기대됩니다. 입력 문서에서 적절한 이벤트에 대해 구문 분석기가 다음 메서드를 호출합니다:

ContentHandler.setDocumentLocator(locator)

응용 프로그램에 문서 이벤트의 출처를 찾기 위한 로케이터(locator)를 제공하기 위해 구문 분석기가 호출합니다.

SAX 구문 분석기가 (절대적으로 필요한 것은 아니지만) 로케이터를 제공할 것을 강력히 권장합니다: 그렇게 한다면, DocumentHandler 인터페이스의 다른 메서드를 호출하기 전에 이 메서드를 호출하여 로케이터를 응용 프로그램에 제공해야 합니다.

로케이터를 사용하면 구문 분석기가 에러를 보고하지 않더라도 응용 프로그램이 문서 관련 이벤트의 종료 위치를 판별할 수 있습니다. 일반적으로, 응용 프로그램은 이 정보를 사용하여 자체 에러(가령 응용 프로그램의 비즈니스 규칙과 일치하지 않는 문자 내용)를 보고합니다. 로케이터가 반환한 정보는 아마도 검색 엔진에 사용하기에는 충분하지 않을 것입니다.

로케이터는 이 인터페이스에서 이벤트를 호출하는 동안에만 올바른 정보를 반환함에 유의하십시오. 응용 프로그램은 다른 시간에 사용하려고 시도해서는 안 됩니다.

ContentHandler.startDocument()

문서 시작 알림을 받습니다.

SAX 구문 분석기는 이 인터페이스나 DTDHandler의 다른 모든 메서드(setDocumentLocator() 제외) 전에 이 메서드를 한 번만 호출합니다.

ContentHandler.endDocument()

문서 끝 알림을 받습니다.

SAX 구문 분석기는 이 메서드를 한 번만 호출하며, 그것이 구문 분석 중에 마지막으로 호출된 메서드가 됩니다. 구문 분석기는 (복구할 수 없는 에러로 인해) 구문 분석을 포기했거나 입력 끝에 도달할 때까지 이 메서드를 호출하지 않아야 합니다.

ContentHandler.startPrefixMapping(prefix, uri)

접두사 URI 이름 공간 매핑의 스코프를 시작합니다.

이 이벤트의 정보는 일반적인 이름 공간 처리에 필요하지 않습니다: SAX XML 판독기는 feature_namespaces 기능이 활성화되면 (기본값) 엘리먼트와 어트리뷰트 이름의 접두사를 자동으로 대체합니다.

그러나, 응용 프로그램이 문자 데이터나 어트리뷰트 값에 접두사를 사용해야 할 때 자동으로 안전하게 확장할 수 없는 경우가 있습니다; startPrefixMapping() 과 endPrefixMapping() 이벤트는 필요한 경우 해당 컨텍스트에서 스스로 접두사를 확장하도록 정보를 응용 프로그램에 제공합니다.

startPrefixMapping() 과 endPrefixMapping() 이벤트는 서로에 대해 올바르게 중첩된다고 보장되지 않음에 유의하십시오: 모든 startPrefixMapping() 이벤트는 해당 startElement() 이벤트 전에 발생하고, 모든 endPrefixMapping() 이벤트는 해당 endElement() 이벤트 후에 발생하지만, 그들 간의 순서는 보장되지 않습니다.

ContentHandler.endPrefixMapping(prefix)

접두사 URI 매핑 스코프를 끝냅니다.

자세한 내용은 startPrefixMapping() 을 참조하십시오. 이 이벤트는 항상 해당 endElement() 이벤트 이후에 발생하지만, endPrefixMapping() 이벤트의 순서는 이 이상으로는 보장되지 않습니다.

ContentHandler.startElement(name, attrs)

이름 공간이 아닌 모드에서 엘리먼트의 시작을 알립니다.

name 매개 변수는 엘리먼트 유형의 원시 XML 1.0 이름을 문자열로 포함하고 attrs 매개 변수는 엘리먼트의 어트리뷰트를 포함하는 Attributes 인터페이스 (Attributes 인터페이스를 참조하십시오)의 객체를 담습니다. attrs로 전달된 객체는 구문 분석기에 의해 재사용 될 수 있습니다; 그것에 대한 참조를 유지하는 것은 어트리뷰트의 사본을 유지하는 신뢰할 수 있는 방법이 아닙니다. 어트리뷰트의 사본을 유지하려면, attrs 객체의 copy() 메서드를 사용하십시오.

ContentHandler.endElement(name)

이름 공간이 아닌 모드에서 엘리먼트의 끝을 알립니다.

name 매개 변수는 startElement() 이벤트와 마찬가지로 엘리먼트 유형의 이름을 포함합니다.

ContentHandler.startElementNS(name, qname, attrs)

이름 공간 모드에서 엘리먼트의 시작을 알립니다.

name 매개 변수는 엘리먼트 유형의 이름을 (uri, localname) 튜플로 포함하고, qname 매개 변수는 소스 문서에서 사용된 원시 XML 1.0 이름을 포함하며, attrs 매개 변수는 엘리먼트의 어트리뷰트를 포함하는 AttributesNS 인터페이스(AttributesNS 인터페이스를 참조하십시오)의 인스턴스를 담습니다. 아무런 이름 공간도 엘리먼트와 연관되지 않았으면 name의 uri 구성 요소는 None입니다. attrs로 전달된 객체는 구문 분석기에 의해 재사용 될 수 있습니다; 그것에 대한 참조를 유지하는 것은 어트리뷰트의 사본을 유지하는 신뢰할 수 있는 방법이 아닙니다. 어트리뷰트의 사본을 유지하려면 attrs 객체의 copy() 메서드를 사용하십시오.

feature_namespace_prefixes 기능이 활성화되지 않는 한, 구문 분석기는 qname 매개 변수를 None으로 설정할 수 있습니다.

ContentHandler.endElementNS(name, qname)

이름 공간 모드에서 엘리먼트의 끝을 알립니다.

name 매개 변수는 startElementNS() 메서드와 마찬가지로 qname 매개 변수처럼 엘리먼트 유형의 이름을 포함합니다.

ContentHandler.characters(content)

문자 데이터의 알림을 받습니다.

구문 분석기는 이 메서드를 호출하여 각 문자 데이터 청크를 보고합니다. SAX 구문 분석기는 연속된 모든 문자 데이터를 단일 청크로 반환하거나 여러 청크로 분할할 수 있습니다; 그러나, 로케이터가 유용한 정보를 제공할 수 있도록, 단일 이벤트의 모든 문자는 같은 외부 엔티티에서 온 것이어야 합니다.

content는 문자열이나 바이트열 인스턴스일 수 있습니다; expat 판독기 모듈은 항상 문자열을 생성합니다.

참고

Python XML Special Interest Group에서 제공된 이전 SAX 1 인터페이스는 이 메서드에 더 Java와 유사한 인터페이스를 사용했습니다. 파이썬에서 사용되는 대부분의 구문 분석기가 구식 인터페이스의 장점을 취하지 않았기 때문에, 더 간단한 서명으로 변경했습니다. 이전 코드를 새 인터페이스로 변환하려면, 이전 offset과 length 매개 변수로 콘텐츠를 슬라이싱하는 대신 content를 사용하십시오.

ContentHandler.ignorableWhitespace(whitespace)

엘리먼트 내용에서 무시할 수 있는 공백에 대한 알림을 받습니다.

유효성 검사 구문 분석기는 무시할 수 있는 공백의 각 청크를 보고하기 위해 이 메서드를 사용해야 합니다 (W3C XML 1.0 권장 사항, 섹션 2.10을 참조하십시오).

SAX 구문 분석기는 모든 연속적인 공백을 단일 청크로 반환하거나 여러 청크로 나눌 수 있습니다; 그러나 로케이터가 유용한 정보를 제공할 수 있도록, 단일 이벤트의 모든 문자는 같은 외부 엔티티에서 온 것이어야 합니다.

ContentHandler.processingInstruction(target, data)

처리 명령의 알림을 받습니다.

구문 분석기는 발견된 각 처리 명령에 대해 이 메서드를 한 번 호출합니다: 처리 명령은 메인 문서 엘리먼트 전후에 발생할 수 있음에 유의하십시오.

SAX 구문 분석기는 이 메서드를 사용하여 XML 선언(XML 1.0, 섹션 2.8)이나 텍스트 선언(XML 1.0, 섹션 4.3.1)을 보고해서는 안 됩니다.

ContentHandler.skippedEntity(name)

건너뛴 엔티티의 알림을 받습니다.

구문 분석기는 각 엔티티를 건너뛸 때마다 이 메서드를 한 번 호출합니다. 유효성을 검사하지 않는 프로세서는 선언을 보지 않으면 엔티티를 건너뛸 수 있습니다 (예를 들어 엔티티가 외부 DTD 서브 세트에서 선언되었기 때문에). feature_external_ges와 feature_external_pes 속성의 값에 따라, 모든 프로세서가 외부 엔티티를 건너뛸 수 있습니다.

DTDHandler 객체

DTDHandler 인스턴스는 다음 메서드를 제공합니다:

DTDHandler.notationDecl(name, publicId, systemId)

표기법 선언 이벤트를 처리합니다.

DTDHandler.unparsedEntityDecl(name, publicId, systemId, ndata)

구문 분석되지 않은 엔티티 선언 이벤트를 처리합니다.

EntityResolver 객체

EntityResolver.resolveEntity(publicId, systemId)

엔티티의 시스템 식별자를 해석하고 읽을 시스템 식별자를 문자열로 반환하거나, 읽을 InputSource를 반환합니다. 기본 구현은 systemId를 반환합니다.

ErrorHandler 객체

Objects with this interface are used to receive error and warning information from the XMLReader. If you create an object that implements this interface, then register the object with your XMLReader, the parser will call the methods in your object to report all warnings and errors. There are three levels of errors available: warnings, (possibly) recoverable errors, and unrecoverable errors. All methods take a SAXParseException as the only parameter. Errors and warnings may be converted to an exception by raising the passed-in exception object.

ErrorHandler.error(exception)

구문 분석기가 복구 가능한 에러를 만나면 호출됩니다. 이 메서드가 예외를 발생시키지 않으면, 구문 분석이 계속될 수 있지만, 응용 프로그램에서 추가 문서 정보를 기대하지 않아야 합니다. 구문 분석기가 계속되도록 허용하면 입력 문서에서 추가 에러가 발견될 수 있습니다.

ErrorHandler.fatalError(exception)

구문 분석기가 복구 불가능한 에러를 만나면 호출됩니다; 이 메서드가 반환될 때 구문 분석이 종료될 것으로 기대합니다.

ErrorHandler.warning(exception)

구문 분석기가 응용 프로그램에 경미한 경고 정보를 제공할 때 호출됩니다. 이 메서드가 반환될 때 구문 분석이 계속될 것으로 기대되며, 문서 정보는 계속 응용 프로그램에 전달됩니다. 이 메서드에서 예외를 발생시키면 구문 분석이 종료됩니다.

LexicalHandler Objects

Optional SAX2 handler for lexical events.

This handler is used to obtain lexical information about an XML document. Lexical information includes information describing the document encoding used and XML comments embedded in the document, as well as section boundaries for the DTD and for any CDATA sections. The lexical handlers are used in the same manner as content handlers.

Set the LexicalHandler of an XMLReader by using the setProperty method with the property identifier 'http://xml.org/sax/properties/lexical-handler'.

LexicalHandler.comment(content)

Reports a comment anywhere in the document (including the DTD and outside the document element).

LexicalHandler.startDTD(name, public_id, system_id)

Reports the start of the DTD declarations if the document has an associated DTD.

LexicalHandler.endDTD()

Reports the end of DTD declaration.

LexicalHandler.startCDATA()

Reports the start of a CDATA marked section.

The contents of the CDATA marked section will be reported through the characters handler.

LexicalHandler.endCDATA()

Reports the end of a CDATA marked section.

xml.sax.saxutils — SAX Utilities

소스 코드: Lib/xml/sax/saxutils.py [https://github.com/python/cpython/tree/main/Lib/xml/sax/saxutils.py]

xml.sax.saxutils 모듈은 SAX 응용 프로그램을 만들 때 직접 사용하거나 베이스 클래스로 사용하는 데 모두 유용한 많은 클래스와 함수를 포함합니다.

xml.sax.saxutils.escape(data, entities={})

data 문자열에 있는 '&', '<' 및 '>'를 이스케이프 합니다.

딕셔너리를 선택적 entities 매개 변수로 전달하여 data의 다른 문자열을 이스케이프 할 수 있습니다. 키와 값은 모두 문자열이어야 합니다; 각 키는 해당 값으로 치환되게 됩니다. 문자 '&', '<' 및 '>'는 entities가 제공되더라도 항상 이스케이프 됩니다.

참고

This function should only be used to escape characters that can’t be used directly in XML. Do not use this function as a general string translation function.

xml.sax.saxutils.unescape(data, entities={})

data 문자열에 있는 '&amp;', '&lt;' 및 '&gt;'를 역 이스케이프 합니다.

딕셔너리를 선택적 entities 매개 변수로 전달하여 data의 다른 문자열을 역 이스케이프 할 수 있습니다. 키와 값은 모두 문자열이어야 합니다; 각 키는 해당 값으로 치환되게 됩니다. '&amp', '&lt;' 및 '&gt;'는 entities가 제공되더라도 항상 역 이스케이프 됩니다.

xml.sax.saxutils.quoteattr(data, entities={})

escape()와 비슷하지만, data가 어트리뷰트 값으로 사용되도록 준비합니다. 반환 값은 추가로 필요한 치환이 적용된 data의 따옴표 붙은 버전입니다. quoteattr()는 data의 내용에 따라 인용 부호 문자를 선택하여 가능하면 문자열의 인용 부호 문자를 인코딩하지 않습니다. 작은따옴표와 큰따옴표가 모두 data에 이미 있으면, 큰따옴표 문자가 인코딩되고, data는 큰따옴표로 묶입니다. 결과 문자열은 어트리뷰트 값으로 직접 사용할 수 있습니다:

>>> print("<element attr=%s>" % quoteattr("ab ' cd \" ef"))
<element attr="ab ' cd &quot; ef">

이 함수는 참조 구상 문법(reference concrete syntax)을 사용하여 HTML이나 모든 SGML을 위한 어트리뷰트 값을 생성할 때 유용합니다.

class xml.sax.saxutils.XMLGenerator(out=None, encoding='iso-8859-1', short_empty_elements=False)

이 클래스는 SAX 이벤트를 다시 XML 문서에 쓰는 방식으로 ContentHandler 인터페이스를 구현합니다. 다시 말해, XMLGenerator를 내용 처리기로 사용하면 구문 분석 중인 원본 문서를 재생산합니다. out은 파일류 객체 여야하고, 기본값은 sys.stdout입니다. encoding은 출력 스트림의 인코딩이고, 기본값은 'iso-8859-1'입니다. short_empty_elements는 내용이 없는 엘리먼트의 형식을 제어합니다: False(기본값)는 시작/끝 태그 쌍으로 출력하고, True로 설정하면 하나의 스스로 닫힌 태그를 출력합니다.

버전 3.2에서 변경: Added the short_empty_elements parameter.

class xml.sax.saxutils.XMLFilterBase(base)

이 클래스는 XMLReader와 클라이언트 응용 프로그램의 이벤트 처리기 사이에 위치하도록 설계되었습니다. 기본적으로, 이것은 요청을 입력기에 전달하고 이벤트를 변경 없이 처리기에 전달할 뿐 아무것도 하지 않지만, 서브 클래스는 특정 메서드를 재정의하여 이벤트 스트림이나 구성 요청이 지나갈 때 수정할 수 있습니다.

xml.sax.saxutils.prepare_input_source(source, base='')

This function takes an input source and an optional base URL and returns a fully resolved InputSource object ready for reading. The input source can be given as a string, a file-like object, or an InputSource object; parsers will use this function to implement the polymorphic source argument to their parse() method.

xml.sax.xmlreader — Interface for XML parsers

소스 코드: Lib/xml/sax/xmlreader.py [https://github.com/python/cpython/tree/main/Lib/xml/sax/xmlreader.py]

SAX 구문 분석기는 XMLReader 인터페이스를 구현합니다. 이들은 함수 create_parser()를 제공해야 하는 파이썬 모듈로 구현됩니다. 이 함수는 새로운 구문 분석기 객체를 만들기 위해 인자 없이 xml.sax.make_parser()에 의해 호출됩니다.

class xml.sax.xmlreader.XMLReader

SAX 구문 분석기가 상속할 수 있는 베이스 클래스.

class xml.sax.xmlreader.IncrementalParser

때에 따라 입력 소스를 한 번에 구문 분석하지 않고 문서를 사용 가능할 때마다 청크로 공급하는 것이 바람직합니다. 입력기(reader)는 일반적으로 전체 파일을 읽지 않고 덩어리로 읽습니다; 여전히 전체 문서가 처리될 때까지 parse()는 반환하지 않습니다. 따라서 parse()의 블로킹 동작이 바람직하지 않을 때 이 인터페이스를 사용해야 합니다.

구문 분석기가 인스턴스화 되면 즉시 feed 메서드에서 데이터를 받아들일 수 있습니다. 구문 분석이 close 호출로 완료된 후, 구문 분석기가 feed나 parse 메서드를 사용하여 새 데이터를 받아들일 준비가 되도록 하려면 reset 메서드를 호출해야 합니다.

이러한 메서드들은 구문 분석 중, 즉 parse가 호출된 후 반환하기 전에 호출하지 않아야 합니다.

기본적으로, 이 클래스는 SAX 2.0 드라이버 작성자의 편의를 위해 IncrementalParser 인터페이스의 feed, close 및 reset 메서드를 사용하여 XMLReader 인터페이스의 parse 메서드를 구현합니다.

class xml.sax.xmlreader.Locator

SAX 이벤트를 문서 위치에 관련시키기 위한 인터페이스. 로케이터 객체는 DocumentHandler 메서드들을 호출하는 동안에만 유효한 결과를 반환합니다; 다른 때에는 결과를 예측할 수 없습니다. 정보가 없으면, 메서드는 None을 반환할 수 있습니다.

class xml.sax.xmlreader.InputSource(system_id=None)

엔티티를 읽기 위해 XMLReader에 필요한 정보의 캡슐화.

이 클래스는 공개 식별자, 시스템 식별자, 바이트 스트림 (문자 인코딩 정보도 포함할 수 있습니다) 및/또는 엔티티의 문자 스트림에 대한 정보를 포함할 수 있습니다.

응용 프로그램은 XMLReader.parse() 메서드에서 사용하고 EntityResolver.resolveEntity에서 반환하기 위해 이 클래스의 객체를 만듭니다.

InputSource는 응용 프로그램에 속하며, XMLReader는 응용 프로그램에서 전달된 InputSource 객체를 수정할 수는 없지만, 복사하여 수정할 수는 있습니다.

class xml.sax.xmlreader.AttributesImpl(attrs)

이것은 Attributes 인터페이스의 구현입니다 (Attributes 인터페이스 절을 참조하십시오). 이것은 startElement() 호출에서 요소 어트리뷰트를 나타내는 딕셔너리류 객체입니다. 가장 유용한 딕셔너리 연산 외에도, 인터페이스에서 설명하는 여러 가지 메서드를 지원합니다. 이 클래스의 객체는 입력기(reader)가 인스턴스화 해야 합니다; attrs는 어트리뷰트 이름에서 어트리뷰트 값으로의 매핑을 포함하는 딕셔너리류 객체여야 합니다.

class xml.sax.xmlreader.AttributesNSImpl(attrs, qnames)

startElementNS()에 전달될 AttributesImpl의 이름 공간(namespace) 인식 변형입니다. AttributesImpl에서 파생되었지만, namespaceURI와 localname의 2-튜플로 구성된 어트리뷰트 이름을 이해합니다. 또한, 원본 문서에 나타나는 정규화 된 이름을 기대하는 여러 가지 메서드를 제공합니다. 이 클래스는 AttributesNS 인터페이스를 구현합니다 (AttributesNS 인터페이스 절을 참조하십시오).

XMLReader 객체

XMLReader 인터페이스는 다음과 같은 메서드를 지원합니다:

XMLReader.parse(source)

SAX 이벤트를 생성하면서 입력 소스를 처리합니다. source 객체는 시스템 식별자 (입력 소스를 식별하는 문자열 – 보통 파일 이름이나 URL), pathlib.Path, 경로류 객체 또는 InputSource 객체일 수 있습니다. parse()가 반환되면, 입력이 완전히 처리된 것이고 구문 분석기 객체를 파기하거나 재설정(reset)할 수 있습니다.

버전 3.5에서 변경: 문자 스트림 지원이 추가되었습니다.

버전 3.8에서 변경: 경로류 객체에 대한 지원이 추가되었습니다.

XMLReader.getContentHandler()

현재 ContentHandler를 반환합니다.

XMLReader.setContentHandler(handler)

현재 ContentHandler를 설정합니다. ContentHandler가 설정되지 않으면, 내용 이벤트가 버려집니다.

XMLReader.getDTDHandler()

현재 DTDHandler를 반환합니다.

XMLReader.setDTDHandler(handler)

현재 DTDHandler를 설정합니다. DTDHandler가 설정되지 않으면, DTD 이벤트가 버려집니다.

XMLReader.getEntityResolver()

현재 EntityResolver를 반환합니다.

XMLReader.setEntityResolver(handler)

현재 EntityResolver를 설정합니다. EntityResolver가 설정되지 않으면, 외부 엔티티를 결정하려고 할 때 엔티티에 대한 시스템 식별자가 열리게 되고, 사용할 수 없으면 실패합니다.

XMLReader.getErrorHandler()

현재 ErrorHandler를 반환합니다.

XMLReader.setErrorHandler(handler)

현재 에러 처리기를 설정합니다. ErrorHandler가 설정되지 않으면, 에러는 예외를 발생시키고, 경고는 인쇄됩니다.

XMLReader.setLocale(locale)

응용 프로그램이 에러와 경고에 대한 로케일을 설정하도록 합니다.

SAX 구문 분석기는 에러와 경고에 대한 지역화를 제공하지 않아도 됩니다; 그러나, 요청된 로케일을 지원할 수 없으면 SAX 예외를 발생시켜야 합니다. 응용 프로그램은 구문 분석 중에 로케일 변경을 요청할 수 있습니다.

XMLReader.getFeature(featurename)

기능 featurename의 현재 설정을 반환합니다. 기능이 인식되지 않으면, SAXNotRecognizedException이 발생합니다. 잘 알려진 기능 이름(featurename)은 모듈 xml.sax.handler에 나열되어 있습니다.

XMLReader.setFeature(featurename, value)

featurename을 value로 설정합니다. 기능이 인식되지 않으면, SAXNotRecognizedException가 발생합니다. 구문 분석기가 기능이나 해당 설정을 지원하지 않으면 SAXNotSupportedException이 발생합니다.

XMLReader.getProperty(propertyname)

속성 propertyname의 현재 설정을 반환합니다. 속성이 인식되지 않으면 SAXNotRecognizedException이 발생합니다. 잘 알려진 속성 이름은 모듈 xml.sax.handler에 나열되어 있습니다.

XMLReader.setProperty(propertyname, value)

propertyname을 value로 설정합니다. 속성이 인식되지 않으면 SAXNotRecognizedException이 발생합니다. 구문 분석기가 속성이나 해당 설정을 지원하지 않으면 SAXNotSupportedException이 발생합니다.

IncrementalParser 객체

IncrementalParser 인스턴스는 다음과 같은 추가 메서드를 제공합니다:

IncrementalParser.feed(data)

data 청크를 처리합니다.

IncrementalParser.close()

문서의 끝을 가정합니다. 끝에서만 확인할 수 있는 올바른 구성(well-formedness) 조건을 확인하고, 처리기를 호출하며 구문 분석 중에 할당된 자원을 정리할 수 있습니다.

IncrementalParser.reset()

이 메서드는 close가 호출된 후에 호출되어 새 문서를 구문 분석할 수 있도록 구문 분석기를 재설정합니다. reset을 호출하지 않고, close 후에 parse나 feed를 호출한 결과는 정의되지 않습니다.

Locator 객체

Locator 인스턴스는 다음 메서드를 제공합니다:

Locator.getColumnNumber()

현재 이벤트가 시작되는 열 번호를 반환합니다.

Locator.getLineNumber()

현재 이벤트가 시작되는 줄 번호를 반환합니다.

Locator.getPublicId()

현재 이벤트의 공개 식별자를 반환합니다.

Locator.getSystemId()

현재 이벤트의 시스템 식별자를 반환합니다.

InputSource 객체

InputSource.setPublicId(id)

이 InputSource의 공개 식별자를 설정합니다.

InputSource.getPublicId()

이 InputSource의 공개 식별자를 반환합니다.

InputSource.setSystemId(id)

이 InputSource의 시스템 식별자를 설정합니다.

InputSource.getSystemId()

이 InputSource의 시스템 식별자를 반환합니다.

InputSource.setEncoding(encoding)

이 InputSource의 문자 인코딩을 설정합니다.

인코딩은 XML 인코딩 선언에 허용되는 문자열이어야 합니다 (XML 권장 사항의 4.3.3 절을 참조하십시오).

InputSource에 문자 스트림도 포함되어 있으면 InputSource의 인코딩 어트리뷰트는 무시됩니다.

InputSource.getEncoding()

이 InputSource의 문자 인코딩을 가져옵니다.

InputSource.setByteStream(bytefile)

이 입력 소스의 바이트 스트림(바이너리 파일)을 설정합니다.

문자 스트림도 지정되어 있으면 SAX 구문 분석기는 이것을 무시하지만, URI 연결 자체를 여는 것보다 바이트 스트림을 먼저 사용합니다.

응용 프로그램이 바이트 스트림의 문자 인코딩을 알고 있으면, setEncoding 메서드로 설정해야 합니다.

InputSource.getByteStream()

이 입력 소스의 바이트 스트림을 가져옵니다.

getEncoding 메서드는 이 바이트 스트림의 문자 인코딩을 반환하거나, 알 수 없으면 None을 반환합니다.

InputSource.setCharacterStream(charfile)

이 입력 소스에 대한 문자 스트림(텍스트 파일)을 설정합니다.

문자 스트림이 지정되면 SAX 구문 분석기는 모든 바이트 스트림을 무시하고 시스템 식별자에 대한 URI 연결을 열려고 시도하지 않습니다.

InputSource.getCharacterStream()

이 입력 소스의 문자 스트림을 가져옵니다.

Attributes 인터페이스

Attributes 객체는 메서드 copy(), get(), __contains__(), items(), keys() 및 values()를 포함하는 매핑 프로토콜의 일부를 구현합니다. 다음과 같은 메서드도 제공됩니다:

Attributes.getLength()

어트리뷰트 수를 반환합니다.

Attributes.getNames()

어트리뷰트의 이름을 반환합니다.

Attributes.getType(name)

어트리뷰트 name의 유형을 반환합니다. 일반적으로 'CDATA'입니다.

Attributes.getValue(name)

어트리뷰트 name의 값을 반환합니다.

AttributesNS 인터페이스

이 인터페이스는 Attributes 인터페이스의 서브 형입니다 (Attributes 인터페이스 절을 참조하십시오). 그 인터페이스에서 지원하는 모든 메서드는 AttributesNS 객체에서도 사용 가능합니다.

다음과 같은 메서드도 제공됩니다:

AttributesNS.getValueByQName(name)

정규화된 이름(qualified name)의 값을 반환합니다.

AttributesNS.getNameByQName(name)

정규화된 name에 대한 (namespace, localname) 쌍을 반환합니다.

AttributesNS.getQNameByName(name)

(namespace, localname) 쌍에 대한 정규화된 이름을 반환합니다.

AttributesNS.getQNames()

모든 어트리뷰트의 정규화된 이름을 반환합니다.

xml.parsers.expat — Fast XML parsing using Expat

경고

pyexpat 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점을 참조하십시오.

xml.parsers.expat 모듈은 Expat 유효성 검사 없는(non-validating) XML 구문 분석기에 대한 파이썬 인터페이스입니다. 이 모듈은 XML 구문 분석기의 현재 상태를 나타내는 단일 확장형 xmlparser를 제공합니다. xmlparser 객체가 만들어진 후, 객체의 다양한 어트리뷰트를 처리기 함수로 설정할 수 있습니다. 그런 다음 XML 문서가 구문 분석기에 공급되면, XML 문서에 있는 문자 데이터와 마크업에 대해 처리기 함수가 호출됩니다.

이 모듈은 pyexpat 모듈을 사용하여 Expat 구문 분석기에 대한 액세스를 제공합니다. pyexpat 모듈의 직접적인 사용은 폐지되었습니다.

이 모듈은 하나의 예외와 하나의 형 객체를 제공합니다:

exception xml.parsers.expat.ExpatError

Expat이 에러를 보고할 때 발생하는 예외. Expat 에러 해석에 대한 자세한 정보는 섹션 ExpatError 예외를 참조하십시오.

exception xml.parsers.expat.error

ExpatError의 별칭.

xml.parsers.expat.XMLParserType

ParserCreate() 함수의 반환 값의 형.

xml.parsers.expat 모듈에는 두 가지 함수가 있습니다:

xml.parsers.expat.ErrorString(errno)

주어진 에러 번호 errno에 대한 설명 문자열을 반환합니다.

xml.parsers.expat.ParserCreate(encoding=None, namespace_separator=None)

새로운 xmlparser 객체를 만들고 반환합니다. 지정되면, encoding은 XML 데이터가 사용하는 인코딩의 이름을 지정하는 문자열이어야 합니다. Expat은 파이썬만큼 많은 인코딩을 지원하지 않으며, 인코딩 레퍼토리를 확장할 수 없습니다; UTF-8, UTF-16, ISO-8859-1 (Latin1) 및 ASCII를 지원합니다. encoding [1] 이 제공되면 문서의 묵시적이나 명시적 인코딩을 대체합니다.

Expat은 XML 이름 공간 처리를 선택적으로 수행할 수 있는데, namespace_separator에 값을 제공하는 것으로 활성화됩니다. 값은 한 문자 문자열이어야 합니다; 문자열의 길이가 잘못되면 ValueError가 발생합니다 (None은 생략과 같은 것으로 간주합니다). 이름 공간 처리가 활성화되면, 이름 공간에 속하는 엘리먼트 형 이름과 어트리뷰트 이름이 확장됩니다. 엘리먼트 처리기 StartElementHandler와 EndElementHandler 에 전달된 엘리먼트 이름은 이름 공간 URI, 이름 공간 구분 문자 및 이름의 로컬 부분의 이어붙이기입니다. 이름 공간 구분자가 0바이트(chr(0))이면 이름 공간 URI와 로컬 부분이 구분자 없이 연결됩니다.

예를 들어, namespace_separator가 스페이스 문자(' ')로 설정되고 다음 문서가 구문 분석되면:

<?xml version="1.0"?>
<root xmlns    = "http://default-namespace.org/"
      xmlns:py = "http://www.python.org/ns/">
  <py:elem1 />
  <elem2 xmlns="" />
</root>

StartElementHandler는 각 엘리먼트에 대해 다음 문자열을 수신합니다:

http://default-namespace.org/ root
http://www.python.org/ns/ elem1
elem2

pyexpat에서 사용하는 Expat 라이브러리의 제한으로 인해, 반환된 xmlparser 인스턴스는 단일 XML 문서를 구문 분석하는 데만 사용할 수 있습니다. 고유한 구문 분석기 인스턴스를 제공하려면 문서마다 ParserCreate를 호출하십시오.

더 보기

Expat XML 구문 분석기 [http://www.libexpat.org/]

Expat 프로젝트의 홈페이지.

XMLParser 객체

xmlparser 객체에는 다음과 같은 메서드가 있습니다:

xmlparser.Parse(data[, isfinal])

문자열 data의 내용을 구문 분석하고, 구문 분석된 데이터를 처리하기 위해 적절한 처리기 함수를 호출합니다. 이 메서드에 대한 최종 호출에서 isfinal은 참이어야 합니다; 여러 파일을 제출하는 것이 아니라, 단일 파일을 여러 조각으로 나누어 구문 분석 할 수 있도록 합니다. data는 언제든지 빈 문자열이 될 수 있습니다.

xmlparser.ParseFile(file)

file 객체에서 읽은 XML 데이터를 구문 분석합니다. file은 더는 데이터가 없을 때 빈 문자열을 반환하는 read(nbytes) 메서드만 제공하면 됩니다.

xmlparser.SetBase(base)

선언에서 시스템 식별자에 있는 상대 URI를 결정하는 데 사용할 베이스를 설정합니다. 상대 식별자 결정은 응용 프로그램에 맡겨집니다: 이 값은 base 인자로 ExternalEntityRefHandler(), NotationDeclHandler() 및 UnparsedEntityDeclHandler() 함수에 전달됩니다.

xmlparser.GetBase()

SetBase()에 대한 이전 호출에 의해 설정된 베이스를 포함하는 문자열을 반환하거나, SetBase()가 호출되지 않았으면 None을 반환합니다.

xmlparser.GetInputContext()

현재 이벤트를 생성한 입력 데이터를 문자열로 반환합니다. 데이터는 텍스트를 포함하는 엔티티의 인코딩을 따릅니다. 이벤트 처리기가 활성화되지 않은 상태에서 호출될 때, 반환 값은 None입니다.

xmlparser.ExternalEntityParserCreate(context[, encoding])

부모 구문 분석기가 구문 분석한 내용이 참조하는 외부 구문 분석된 엔티티를 구문 분석하는 데 사용할 수 있는 “자식” 구문 분석기를 만듭니다. context 매개 변수는 아래 설명된 ExternalEntityRefHandler() 처리기 함수에 전달된 문자열이어야 합니다. 자식 구문 분석기는 ordered_attributes와 specified_attributes가 이 구문 분석기의 값으로 설정된 상태로 만들어집니다.

xmlparser.SetParamEntityParsing(flag)

매개 변수 엔티티(외부 DTD 부분 집합을 포함합니다)의 구문 분석을 제어합니다. 가능한 flag 값은 XML_PARAM_ENTITY_PARSING_NEVER, XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE 및 XML_PARAM_ENTITY_PARSING_ALWAYS입니다. 플래그 설정에 성공하면 참을 반환합니다.

xmlparser.UseForeignDTD([flag])

flag에 대해 참값(기본값)으로 이를 호출하면 Expat이 대체 DTD를 로드할 수 있도록 모든 인자를 None으로 ExternalEntityRefHandler를 호출하도록 합니다. 문서에 문서 형 선언이 포함되어 있지 않으면, ExternalEntityRefHandler는 여전히 호출되지만, StartDoctypeDeclHandler와 EndDoctypeDeclHandler는 호출되지 않습니다.

flag에 대해 거짓 값을 전달하면 참값을 전달한 이전 호출이 취소되지만, 그렇지 않으면 효과가 없습니다.

이 메서드는 Parse()나 ParseFile() 메서드가 호출되기 전에만 호출 할 수 있습니다; 이들 중 어느 것이라도 호출된 후에 호출하면 code 어트리뷰트가 errors.codes[errors.XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING]로 설정된 ExpatError가 발생합니다.

xmlparser.SetReparseDeferralEnabled(enabled)

경고

Calling SetReparseDeferralEnabled(False) has security implications, as detailed below; please make sure to understand these consequences prior to using the SetReparseDeferralEnabled method.

Expat 2.6.0 introduced a security mechanism called “reparse deferral” where instead of causing denial of service through quadratic runtime from reparsing large tokens, reparsing of unfinished tokens is now delayed by default until a sufficient amount of input is reached. Due to this delay, registered handlers may — depending of the sizing of input chunks pushed to Expat — no longer be called right after pushing new input to the parser. Where immediate feedback and taking over responsibility of protecting against denial of service from large tokens are both wanted, calling SetReparseDeferralEnabled(False) disables reparse deferral for the current Expat parser instance, temporarily or altogether. Calling SetReparseDeferralEnabled(True) allows re-enabling reparse deferral.

Note that SetReparseDeferralEnabled() has been backported to some prior releases of CPython as a security fix. Check for availability of SetReparseDeferralEnabled() using hasattr() if used in code running across a variety of Python versions.

Added in version 3.13.

xmlparser.GetReparseDeferralEnabled()

Returns whether reparse deferral is currently enabled for the given Expat parser instance.

Added in version 3.13.

xmlparser 객체에는 다음과 같은 어트리뷰트가 있습니다:

xmlparser.buffer_size

buffer_text가 참일 때 사용되는 버퍼의 크기. 이 어트리뷰트에 새로운 정숫값을 대입하여 새로운 버퍼 크기를 설정할 수 있습니다. 크기가 변경되면 버퍼가 플러시 됩니다.

xmlparser.buffer_text

Setting this to true causes the xmlparser object to buffer textual content returned by Expat to avoid multiple calls to the CharacterDataHandler() callback whenever possible. This can improve performance substantially since Expat normally breaks character data into chunks at every line ending. This attribute is false by default, and may be changed at any time. Note that when it is false, data that does not contain newlines may be chunked too.

xmlparser.buffer_used

buffer_text가 활성화되면, 버퍼에 저장된 바이트 수. 이 바이트열은 UTF-8로 인코딩된 텍스트를 나타냅니다. buffer_text가 거짓이면 이 어트리뷰트는 의미가 없습니다.

xmlparser.ordered_attributes

이 어트리뷰트를 0이 아닌 정수로 설정하면 어트리뷰트가 딕셔너리가 아닌 리스트로 보고됩니다. 어트리뷰트는 문서 텍스트에서 발견된 순서대로 표시됩니다. 각 어트리뷰트에 대해, 두 가지 리스트 항목이 표시됩니다: 어트리뷰트 이름과 어트리뷰트 값. (이 모듈의 이전 버전도 이 형식을 사용했습니다.) 기본적으로, 이 어트리뷰트는 거짓입니다; 언제든지 변경될 수 있습니다.

xmlparser.specified_attributes

0이 아닌 정수로 설정되면, 구문 분석기는 문서 인스턴스에 지정된 어트리뷰트만 보고하고 어트리뷰트 선언에서 파생된 어트리뷰트는 보고하지 않습니다. 이를 설정한 응용 프로그램은 XML 프로세서의 동작에 대한 표준을 준수하기 위해 선언에서 사용 가능한 추가 정보를 사용할 때 특히 주의해야 합니다. 기본적으로, 이 어트리뷰트는 거짓입니다; 언제든지 변경될 수 있습니다.

다음 어트리뷰트는 xmlparser 객체가 만난 가장 최근 에러와 관련된 값을 포함하며, 일단 Parse()나 ParseFile()에 대한 호출이 xml.parsers.expat.ExpatError 예외를 발생시켰을 때만 올바른 값을 갖습니다.

xmlparser.ErrorByteIndex

에러가 발생한 바이트 인덱스.

xmlparser.ErrorCode

문제를 지정하는 숫자 코드. 이 값은 ErrorString() 함수에 전달되거나, errors 객체에 정의된 상수 중 하나와 비교될 수 있습니다.

xmlparser.ErrorColumnNumber

에러가 발생한 열 번호.

xmlparser.ErrorLineNumber

에러가 발생한 줄 번호.

다음 어트리뷰트는 xmlparser 객체의 현재 구문 분석 위치와 관련된 값을 포함합니다. 구문 분석 이벤트를 보고하는 콜백 중에, 이들은 이벤트를 생성한 첫 번째 문자 시퀀스의 위치를 나타냅니다. 콜백 외부에서 호출되면, 표시된 위치는 마지막 구문 분석 이벤트 바로 다음입니다 (관련 콜백이 있는지에 관계없이).

xmlparser.CurrentByteIndex

구문 분석기 입력의 현재 바이트 인덱스.

xmlparser.CurrentColumnNumber

구문 분석기 입력의 현재 열 번호.

xmlparser.CurrentLineNumber

구문 분석기 입력의 현재 줄 번호.

설정할 수 있는 처리기 목록은 다음과 같습니다. xmlparser 객체 o에 처리기를 설정하려면, o.handlername = func를 사용하십시오. handlername은 다음 목록에서 취해야 하며, func는 올바른 수의 인자를 받아들이는 콜러블 객체여야 합니다. 달리 명시되지 않는 한, 인자는 모두 문자열입니다.

xmlparser.XmlDeclHandler(version, encoding, standalone)

XML 선언이 구문 분석될 때 호출됩니다. XML 선언은 XML 권장 사항의 해당 버전에 대한 (선택적) 선언, 문서 텍스트의 인코딩 및 선택적 “독립형(standalone)” 선언입니다. version과 encoding은 문자열이며, standalone은 문서가 독립형으로 선언되면 1이 되고, 독립형이 아닌 것으로 선언되면 0이 됩니다, 또는 독립형 절이 생략되면 -1입니다. Expat 버전 1.95.0 이상에서만 사용할 수 있습니다.

xmlparser.StartDoctypeDeclHandler(doctypeName, systemId, publicId, has_internal_subset)

Expat이 문서 형 선언(<!DOCTYPE ...) 구문 분석을 시작할 때 호출됩니다. doctypeName은 제시된 대로 정확하게 제공됩니다. systemId와 publicId 매개 변수는 지정되면 시스템(system)과 공용(public) 식별자를, 생략되면 None을 제공합니다. 문서에 내부 문서 선언 부분집합이 포함되어 있으면 has_internal_subset은 참입니다. Expat 버전 1.2 이상이 필요합니다.

xmlparser.EndDoctypeDeclHandler()

Expat이 문서 형 선언 구문 분석을 완료할 때 호출됩니다. Expat 버전 1.2 이상이 필요합니다.

xmlparser.ElementDeclHandler(name, model)

각 엘리먼트 형 선언마다 한 번씩 호출됩니다. name은 엘리먼트 형의 이름이고, model은 콘텐츠 모델의 표현입니다.

xmlparser.AttlistDeclHandler(elname, attname, type, default, required)

엘리먼트 형에 대해 선언된 어트리뷰트마다 호출됩니다. 어트리뷰트 리스트 선언이 세 개의 어트리뷰트를 선언하면 이 처리기는 어트리뷰트마다 한 번씩 세 번 호출됩니다. elname은 선언이 적용되는 엘리먼트의 이름이고 attname은 선언된 어트리뷰트의 이름입니다. 어트리뷰트 형은 type으로 전달된 문자열입니다; 가능한 값은 'CDATA', 'ID', 'IDREF', … 입니다. default는 어트리뷰트가 문서 인스턴스에 의해 지정되지 않을 때 사용되는 어트리뷰트의 기본값을 제공하거나, 기본값이 없으면 None입니다 (#IMPLIED 값). 문서 인스턴스에서 어트리뷰트가 필수면, required는 참입니다. Expat 버전 1.95.0 이상이 필요합니다.

xmlparser.StartElementHandler(name, attributes)

모든 엘리먼트의 시작에서 호출됩니다. name은 엘리먼트 이름을 포함하는 문자열이고, attributes는 엘리먼트 어트리뷰트입니다. ordered_attributes가 참이면, 이것은 리스트입니다 (자세한 설명은 ordered_attributes를 참조하십시오). 그렇지 않으면 이름을 값으로 매핑하는 딕셔너리입니다.

xmlparser.EndElementHandler(name)

모든 엘리먼트의 끝에서 호출됩니다.

xmlparser.ProcessingInstructionHandler(target, data)

모든 처리 명령어(processing instruction)에서 호출됩니다.

xmlparser.CharacterDataHandler(data)

Called for character data. This will be called for normal character data, CDATA marked content, and ignorable whitespace. Applications which must distinguish these cases can use the StartCdataSectionHandler, EndCdataSectionHandler, and ElementDeclHandler callbacks to collect the required information. Note that the character data may be chunked even if it is short and so you may receive more than one call to CharacterDataHandler(). Set the buffer_text instance attribute to True to avoid that.

xmlparser.UnparsedEntityDeclHandler(entityName, base, systemId, publicId, notationName)

구문 분석되지 않은 (NDATA) 엔티티 선언에 대해 호출됩니다. 이것은 Expat 라이브러리 1.2 버전에만 존재합니다; 최신 버전의 경우 EntityDeclHandler를 대신 사용하십시오. (Expat 라이브러리의 하부 함수는 더는 사용되지 않는 것으로 선언되었습니다.)

xmlparser.EntityDeclHandler(entityName, is_parameter_entity, value, base, systemId, publicId, notationName)

모든 엔티티 선언에 대해 호출됩니다. 파라미터와 내부 엔티티의 경우, value는 엔티티의 선언된 내용을 제공하는 문자열입니다; 외부 엔티티의 경우 None이 됩니다. notationName 매개 변수는 구문 분석된 엔티티의 경우 None이고, 구문 분석되지 않은 엔티티의 경우는 표기법 이름입니다. 엔티티가 파라미터 엔티티인 경우 is_parameter_entity는 참이고, 일반 엔티티의 경우 거짓입니다 (대부분 응용 프로그램은 일반 엔티티만 고려하면 됩니다). Expat 라이브러리 버전 1.95.0부터 사용 가능합니다.

xmlparser.NotationDeclHandler(notationName, base, systemId, publicId)

표기법 선언에 대해 호출됩니다. notationName, base, systemId 및 publicId는 주어지면 문자열입니다. 공용 식별자를 생략하면, publicId는 None이 됩니다.

xmlparser.StartNamespaceDeclHandler(prefix, uri)

엘리먼트에 이름 공간 선언이 포함되어 있으면 호출됩니다. 이름 공간 선언은 선언이 배치된 엘리먼트에 대한 StartElementHandler 가 호출되기 전에 처리됩니다.

xmlparser.EndNamespaceDeclHandler(prefix)

이름 공간 선언이 포함된 엘리먼트에 대해 닫기 태그에 도달하면 호출됩니다. 이는 각 이름 공간 선언 스코프의 시작을 나타내기 위해 StartNamespaceDeclHandler 가 호출된 순서와 반대로 엘리먼트의 각 이름 공간 선언에 대해 한 번씩 호출됩니다. 이 처리기에 대한 호출은 엘리먼트의 끝을 위한 해당 EndElementHandler 이후에 수행됩니다.

xmlparser.CommentHandler(data)

주석에 대해 호출됩니다. data는 주석의 텍스트이며, 선행 '<!--'와 후행 '-->'를 제외합니다.

xmlparser.StartCdataSectionHandler()

CDATA 섹션의 시작에서 호출됩니다. CDATA 섹션의 구문적 시작과 종료를 식별할 수 있으려면 이것과 EndCdataSectionHandler 가 필요합니다.

xmlparser.EndCdataSectionHandler()

CDATA 섹션의 끝에서 호출됩니다.

xmlparser.DefaultHandler(data)

적용 가능한 처리기가 지정되지 않은 XML 문서의 모든 문자에 대해 호출됩니다. 이것은 보고될 수 있지만, 처리기가 제공되지 않은 구성의 일부인 문자를 의미합니다.

xmlparser.DefaultHandlerExpand(data)

이것은 DefaultHandler()와 같지만, 내부 엔티티의 확장을 막지 않습니다. 엔티티 참조는 기본 처리기로 전달되지 않습니다.

xmlparser.NotStandaloneHandler()

XML 문서가 독립형 문서로 선언되지 않은 경우 호출됩니다. 외부 부분 집합이나 파라미터 엔티티에 대한 참조가 있지만, XML 선언에서 XML 선언이 standalone을 yes로 설정하지 않은 경우에 발생합니다. 이 처리기가 0을 반환하면, 구문 분석기는 XML_ERROR_NOT_STANDALONE 에러를 발생시킵니다. 이 처리기가 설정되지 않으면, 이 조건에 대해 구문 분석기가 예외를 발생시키지 않습니다.

xmlparser.ExternalEntityRefHandler(context, base, systemId, publicId)

외부 엔티티에 대한 참조에 대해 호출됩니다. base는 SetBase()에 대한 이전 호출에서 설정한 현재 베이스입니다. 공용과 시스템 식별자, systemId 및 publicId는 지정되면 문자열입니다; 공용 식별자가 제공되지 않으면 publicId는 None이 됩니다. context 값은 불투명하며 아래 설명된 대로만 사용해야 합니다.

외부 엔티티를 구문 분석하려면, 이 처리기를 구현해야 합니다. ExternalEntityParserCreate(context)를 사용하여 서브 구문 분석기를 만들고, 적절한 콜백으로 초기화하고, 엔티티를 구문 분석해야 합니다. 이 처리기는 정수를 반환해야 합니다; 0을 반환하면, 구문 분석기는 XML_ERROR_EXTERNAL_ENTITY_HANDLING 에러를 발생시키고, 그렇지 않으면 구문 분석이 계속됩니다.

이 처리기가 제공되지 않으면, 외부 엔티티는 제공된다면 DefaultHandler 콜백에 의해 보고됩니다.

ExpatError 예외

ExpatError 예외에는 여러 가지 흥미로운 어트리뷰트가 있습니다:

ExpatError.code

특정 에러에 대한 Expat의 내부 에러 번호. errors.messages 딕셔너리는 이러한 에러 번호를 Expat의 에러 메시지에 매핑합니다. 예를 들면:

from xml.parsers.expat import ParserCreate, ExpatError, errors

p = ParserCreate()
try:
    p.Parse(some_xml_document)
except ExpatError as err:
    print("Error:", errors.messages[err.code])

errors 모듈은 에러 메시지 상수와 이러한 메시지를 에러 코드로 역 매핑하는 딕셔너리 codes도 제공합니다, 아래를 참조하십시오.

ExpatError.lineno

에러가 감지된 줄 번호. 첫 번째 줄은 1로 번호가 매겨집니다.

ExpatError.offset

에러가 발생한 줄에서의 문자 오프셋. 첫 번째 열의 번호는 0입니다.

예

다음 프로그램은 인자를 출력하기만 하는 세 개의 처리기를 정의합니다.

import xml.parsers.expat

# 3 handler functions
def start_element(name, attrs):
    print('Start element:', name, attrs)
def end_element(name):
    print('End element:', name)
def char_data(data):
    print('Character data:', repr(data))

p = xml.parsers.expat.ParserCreate()

p.StartElementHandler = start_element
p.EndElementHandler = end_element
p.CharacterDataHandler = char_data

p.Parse("""<?xml version="1.0"?>
<parent id="top"><child1 name="paul">Text goes here</child1>
<child2 name="fred">More text</child2>
</parent>""", 1)

이 프로그램의 출력은 다음과 같습니다:

Start element: parent {'id': 'top'}
Start element: child1 {'name': 'paul'}
Character data: 'Text goes here'
End element: child1
Character data: '\n'
Start element: child2 {'name': 'fred'}
Character data: 'More text'
End element: child2
Character data: '\n'
End element: parent

콘텐츠 모델 기술

콘텐츠 모델은 중첩된 튜플을 사용하여 기술됩니다. 각 튜플에는 네 가지 값이 있습니다: 형, 수량 지정자(quantifier), 이름 및 자식 튜플. 자식은 단순히 추가의 콘텐츠 모델 기술입니다.

처음 두 필드의 값은 xml.parsers.expat.model 모듈에 정의된 상수입니다. 이 상수는 두 그룹으로 모을 수 있습니다: 모델 형 그룹과 수량 지정자 그룹.

모델 형 그룹의 상수는 다음과 같습니다:

xml.parsers.expat.model.XML_CTYPE_ANY

모델 이름으로 명명된 엘리먼트가 콘텐츠 모델 ANY를 갖도록 선언되었습니다.

xml.parsers.expat.model.XML_CTYPE_CHOICE

명명된 엘리먼트가 여러 옵션 중에서 선택할 수 있도록 합니다; 이것은 (A | B | C)와 같은 콘텐츠 모델에 사용됩니다.

xml.parsers.expat.model.XML_CTYPE_EMPTY

EMPTY로 선언된 엘리먼트는 이 모델 형을 갖습니다.

xml.parsers.expat.model.XML_CTYPE_MIXED

xml.parsers.expat.model.XML_CTYPE_NAME

xml.parsers.expat.model.XML_CTYPE_SEQ

일련의 모델이 차례로 나타나는 모델은 이 모델 형으로 표시됩니다. (A, B, C)와 같은 모델에 사용됩니다.

수량 지정자 그룹의 상수는 다음과 같습니다:

xml.parsers.expat.model.XML_CQUANT_NONE

수정자가 제공되지 않아서, A와 같이, 정확히 한 번만 나타날 수 있습니다.

xml.parsers.expat.model.XML_CQUANT_OPT

모델은 선택적입니다: A? 와 같이, 한 번만 나타나거나 전혀 나타나지 않을 수 있습니다.

xml.parsers.expat.model.XML_CQUANT_PLUS

모델은 한 번 이상 발생해야 합니다 (A+처럼).

xml.parsers.expat.model.XML_CQUANT_REP

A*와 같이, 모델은 0번 이상 나타나야 합니다.

Expat 에러 상수

xml.parsers.expat.errors 모듈에는 다음과 같은 상수가 제공됩니다. 이 상수는 에러가 발생했을 때 발생하는 ExpatError 예외 객체의 일부 어트리뷰트를 해석하는 데 유용합니다. 이전 버전과의 호환성을 위해, 상숫값은 숫자 에러 code가 아니라 에러 message이므로, code 어트리뷰트를 errors.codes[errors.XML_ERROR_CONSTANT_NAME]와 비교합니다.

errors 모듈에는 다음과 같은 어트리뷰트가 있습니다:

xml.parsers.expat.errors.codes

문자열 설명을 에러 코드에 매핑하는 딕셔너리.

Added in version 3.2.

xml.parsers.expat.errors.messages

숫자 에러 코드를 문자열 설명에 매핑하는 딕셔너리.

Added in version 3.2.

xml.parsers.expat.errors.XML_ERROR_ASYNC_ENTITY

xml.parsers.expat.errors.XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF

어트리뷰트 값의 엔티티 참조가 내부 엔티티 대신 외부 엔티티를 참조합니다.

xml.parsers.expat.errors.XML_ERROR_BAD_CHAR_REF

문자 참조가 XML에서 잘못된 문자를 가리킵니다 (예를 들어, 문자 0 또는 ‘&#0;’).

xml.parsers.expat.errors.XML_ERROR_BINARY_ENTITY_REF

엔티티 참조가 표기법으로 선언된 엔티티를 참조해서, 구문 분석할 수 없습니다.

xml.parsers.expat.errors.XML_ERROR_DUPLICATE_ATTRIBUTE

시작 태그에서 어트리뷰트가 두 번 이상 사용되었습니다.

xml.parsers.expat.errors.XML_ERROR_INCORRECT_ENCODING

xml.parsers.expat.errors.XML_ERROR_INVALID_TOKEN

입력 바이트를 문자에 올바르게 대입할 수 없을 때 발생합니다; 예를 들어, UTF-8 입력 스트림의 NUL 바이트(값 0).

xml.parsers.expat.errors.XML_ERROR_JUNK_AFTER_DOC_ELEMENT

문서 엘리먼트 다음에 공백 이외의 것이 나타났습니다.

xml.parsers.expat.errors.XML_ERROR_MISPLACED_XML_PI

입력 데이터의 시작 이외의 곳에서 XML 선언이 발견되었습니다.

xml.parsers.expat.errors.XML_ERROR_NO_ELEMENTS

문서에 엘리먼트가 없습니다 (XML은 모든 문서에 정확히 하나의 최상위 엘리먼트가 포함되어야 함을 요구합니다).

xml.parsers.expat.errors.XML_ERROR_NO_MEMORY

Expat이 내부적으로 메모리를 할당하지 못했습니다.

xml.parsers.expat.errors.XML_ERROR_PARAM_ENTITY_REF

파라미터 엔티티 참조가 허용되지 않는 위치에서 발견되었습니다.

xml.parsers.expat.errors.XML_ERROR_PARTIAL_CHAR

입력에서 불완전한 문자가 발견되었습니다.

xml.parsers.expat.errors.XML_ERROR_RECURSIVE_ENTITY_REF

엔티티 참조가 같은 엔티티에 대한 다른 참조를 포함합니다; 어쩌면 다른 이름을 통해서, 그리고 어쩌면 간접적으로.

xml.parsers.expat.errors.XML_ERROR_SYNTAX

지정되지 않은 구문 에러를 만났습니다.

xml.parsers.expat.errors.XML_ERROR_TAG_MISMATCH

종료 태그가 가장 안쪽에 있는 시작 태그와 일치하지 않습니다.

xml.parsers.expat.errors.XML_ERROR_UNCLOSED_TOKEN

어떤 토큰이 (가령 시작 태그) 스트림이 끝나기 전에 닫히지 않았거나 다음 토큰을 만났습니다.

xml.parsers.expat.errors.XML_ERROR_UNDEFINED_ENTITY

정의되지 않은 엔티티를 참조했습니다.

xml.parsers.expat.errors.XML_ERROR_UNKNOWN_ENCODING

문서 인코딩을 Expat에서 지원하지 않습니다.

xml.parsers.expat.errors.XML_ERROR_UNCLOSED_CDATA_SECTION

CDATA 표시 섹션이 닫히지 않았습니다.

xml.parsers.expat.errors.XML_ERROR_EXTERNAL_ENTITY_HANDLING

xml.parsers.expat.errors.XML_ERROR_NOT_STANDALONE

문서가 XML 선언에서 자신을 “독립형”으로 선언했지만 구문 분석기가 독립형이 아니라고 결정했으며 NotStandaloneHandler 가 설정되고 0을 반환했습니다.

xml.parsers.expat.errors.XML_ERROR_UNEXPECTED_STATE

xml.parsers.expat.errors.XML_ERROR_ENTITY_DECLARED_IN_PE

xml.parsers.expat.errors.XML_ERROR_FEATURE_REQUIRES_XML_DTD

DTD 지원이 컴파일되어 있어야 하는 작업이 요청되었지만, Expat이 DTD 지원 없이 구성되었습니다. xml.parsers.expat 모듈의 표준 빌드에서 이것이 보고되어서는 안 됩니다.

xml.parsers.expat.errors.XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING

구문 분석이 시작된 후에 구문 분석이 시작되기 전에만 변경할 수 있는 동작 변경이 요청되었습니다. 이것은 (현재) UseForeignDTD()에 의해서만 발생합니다.

xml.parsers.expat.errors.XML_ERROR_UNBOUND_PREFIX

이름 공간 처리가 활성화되었을 때 선언되지 않은 접두사가 발견되었습니다.

xml.parsers.expat.errors.XML_ERROR_UNDECLARING_PREFIX

문서가 접두사와 연관된 이름 공간 선언을 제거하려고 했습니다.

xml.parsers.expat.errors.XML_ERROR_INCOMPLETE_PE

파라미터 엔티티에 불완전한 마크업이 포함되어 있습니다.

xml.parsers.expat.errors.XML_ERROR_XML_DECL

문서에 문서 엘리먼트가 전혀 없습니다.

xml.parsers.expat.errors.XML_ERROR_TEXT_DECL

외부 엔티티에 있는 텍스트 선언을 구문 분석하는 중 에러가 발생했습니다.

xml.parsers.expat.errors.XML_ERROR_PUBLICID

허용되지 않는 문자가 공용 id에서 발견되었습니다.

xml.parsers.expat.errors.XML_ERROR_SUSPENDED

일시 중지된 구문 분석기에 작업이 요청되었지만, 허용되지 않습니다. 여기에는 추가 입력을 제공하거나 구문 분석기를 중지하려는 시도가 포함됩니다.

xml.parsers.expat.errors.XML_ERROR_NOT_SUSPENDED

구문 분석기가 일시 중지되지 않았을 때 구문 분석기를 재개하려고 했습니다.

xml.parsers.expat.errors.XML_ERROR_ABORTED

이것은 파이썬 응용 프로그램에 보고되어서는 안 됩니다.

xml.parsers.expat.errors.XML_ERROR_FINISHED

입력을 구문 분석하는 것을 종료한 구문 분석기에 작업을 요청했지만, 허용되지 않습니다. 여기에는 추가 입력을 제공하거나 구문 분석기를 중지하려는 시도가 포함됩니다.

xml.parsers.expat.errors.XML_ERROR_SUSPEND_PE

xml.parsers.expat.errors.XML_ERROR_RESERVED_PREFIX_XML

An attempt was made to undeclare reserved namespace prefix xml or to bind it to another namespace URI.

xml.parsers.expat.errors.XML_ERROR_RESERVED_PREFIX_XMLNS

An attempt was made to declare or undeclare reserved namespace prefix xmlns.

xml.parsers.expat.errors.XML_ERROR_RESERVED_NAMESPACE_URI

An attempt was made to bind the URI of one the reserved namespace prefixes xml and xmlns to another namespace prefix.

xml.parsers.expat.errors.XML_ERROR_INVALID_ARGUMENT

이것은 파이썬 응용 프로그램에 보고되어서는 안 됩니다.

xml.parsers.expat.errors.XML_ERROR_NO_BUFFER

이것은 파이썬 응용 프로그램에 보고되어서는 안 됩니다.

xml.parsers.expat.errors.XML_ERROR_AMPLIFICATION_LIMIT_BREACH

The limit on input amplification factor (from DTD and entities) has been breached.

각주

[1]

XML 출력에 포함된 인코딩 문자열은 적절한 표준을 준수해야 합니다. 예를 들어, “UTF-8”은 유효하지만, “UTF8”은 유효하지 않습니다. https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl 과 https://www.iana.org/assignments/character-sets/character-sets.xhtml 을 참조하십시오.

인터넷 프로토콜과 지원

The modules described in this chapter implement internet protocols and support for related technology. They are all implemented in Python. Most of these modules require the presence of the system-dependent module socket, which is currently supported on most popular platforms. Here is an overview:

webbrowser — Convenient web-browser controller

Error

open()

open_new()

open_new_tab()

get()

register()

브라우저 제어기 객체

name

open()

open_new()

open_new_tab()

wsgiref — WSGI Utilities and Reference Implementation

wsgiref.util – WSGI 환경 유틸리티

guess_scheme()

request_uri()

application_uri()

shift_path_info()

setup_testing_defaults()

is_hop_by_hop()

FileWrapper

wsgiref.headers – WSGI 응답 헤더 도구

Headers

get_all()

add_header()

wsgiref.simple_server – 간단한 WSGI HTTP 서버

make_server()

demo_app()

WSGIServer

set_app()

get_app()

WSGIRequestHandler

get_environ()

get_stderr()

handle()

wsgiref.validate — WSGI 적합성 검사기

validator()

wsgiref.handlers – 서버/게이트웨이 베이스 클래스

CGIHandler

IISCGIHandler

BaseCGIHandler

SimpleHandler

BaseHandler

run()

_write()

_flush()

get_stdin()

get_stderr()

add_cgi_vars()

wsgi_multithread

wsgi_multiprocess

wsgi_run_once

os_environ

server_software

get_scheme()

setup_environ()

log_exception()

traceback_limit

error_output()

error_status

error_headers

error_body

wsgi_file_wrapper

sendfile()

origin_server

http_version

read_environ()

wsgiref.types – WSGI types for static type checking

StartResponse

WSGIEnvironment

WSGIApplication

InputStream

ErrorStream

FileWrapper

예제

urllib — URL handling modules

urllib.request — Extensible library for opening URLs

urlopen()

install_opener()

build_opener()

pathname2url()

url2pathname()

getproxies()

Request

OpenerDirector

BaseHandler

HTTPDefaultErrorHandler

HTTPRedirectHandler

HTTPCookieProcessor

ProxyHandler

HTTPPasswordMgr

HTTPPasswordMgrWithDefaultRealm

HTTPPasswordMgrWithPriorAuth

AbstractBasicAuthHandler

HTTPBasicAuthHandler

ProxyBasicAuthHandler

AbstractDigestAuthHandler

HTTPDigestAuthHandler

ProxyDigestAuthHandler

HTTPHandler

HTTPSHandler

FileHandler

DataHandler

FTPHandler

CacheFTPHandler

UnknownHandler

HTTPErrorProcessor

Request 객체

full_url

type

host

origin_req_host

selector

data

unverifiable

method

get_method()

add_header()

add_unredirected_header()

has_header()

remove_header()

get_full_url()

set_proxy()

get_header()

header_items()

OpenerDirector 객체

add_handler()

open()

error()

BaseHandler 객체

add_parent()

close()

parent

default_open()

unknown_open()

http_error_default()

HTTPRedirectHandler 객체

redirect_request()

http_error_301()

http_error_302()

http_error_303()

http_error_307()

http_error_308()

HTTPCookieProcessor 객체

cookiejar

ProxyHandler 객체

HTTPPasswordMgr 객체

add_password()

find_user_password()

HTTPPasswordMgrWithPriorAuth 객체

add_password()

find_user_password()

update_authenticated()

is_authenticated()

AbstractBasicAuthHandler 객체

http_error_auth_reqed()

HTTPBasicAuthHandler 객체

http_error_401()

ProxyBasicAuthHandler 객체

http_error_407()

AbstractDigestAuthHandler 객체

http_error_auth_reqed()

HTTPDigestAuthHandler 객체

http_error_401()

ProxyDigestAuthHandler 객체

http_error_407()

HTTPHandler 객체

http_open()

HTTPSHandler 객체

https_open()

FileHandler 객체

file_open()

DataHandler 객체

data_open()

FTPHandler 객체

ftp_open()

CacheFTPHandler 객체

setTimeout()

setMaxConns()

UnknownHandler 객체

unknown_open()

HTTPErrorProcessor 객체

http_response()

https_response()

예

레거시 인터페이스

urlretrieve()

urlcleanup()

urllib.request 제약 사항

urllib.response — urllib가 사용하는 응답 클래스

addinfourl

url

headers

status

geturl()

info()

code

getcode()

urllib.parse — Parse URLs into components

URL 구문 분석

urlparse()

parse_qs()

parse_qsl()

urlunparse()

urlsplit()

urlunsplit()

urljoin()

urldefrag()

unwrap()

URL parsing security

ASCII로 인코딩된 바이트열 구문 분석

구조화된 구문 분석 결과

geturl()

DefragResult

ParseResult

SplitResult

DefragResultBytes

ParseResultBytes

SplitResultBytes

URL 인용

quote()

quote_plus()

quote_from_bytes()

unquote()

unquote_plus()

unquote_to_bytes()

urlencode()

urllib.error — Exception classes raised by urllib.request

URLError

reason

HTTPError

url

code

reason

headers

fp

ContentTooShortError

content

urllib.robotparser — Parser for robots.txt

RobotFileParser

set_url()

read()

parse()

can_fetch()

mtime()

modified()

crawl_delay()

request_rate()

site_maps()

http — HTTP modules

HTTPStatus

HTTP 상태 코드

HTTP status category

HTTPMethod

HTTP methods

http.client — HTTP protocol client

HTTPConnection

HTTPSConnection

HTTPResponse

parse_headers()

HTTPException

NotConnected

InvalidURL

UnknownProtocol

UnknownTransferEncoding

UnimplementedFileMode

IncompleteRead

ImproperConnectionState

CannotSendRequest

CannotSendHeader

ResponseNotReady

BadStatusLine

LineTooLong

RemoteDisconnected

HTTP_PORT

HTTPS_PORT

responses

HTTPConnection 객체

request()

getresponse()

set_debuglevel()

set_tunnel()

get_proxy_response_headers()

connect()

close()

blocksize

putrequest()

putheader()

endheaders()

send()

HTTPResponse 객체

read()

readinto()

getheader()

getheaders()

fileno()

msg

version

url

headers

status

reason

debuglevel

closed

geturl()

info()

getcode()

예

HTTPMessage 객체

HTTPMessage

ftplib — FTP protocol client

Reference

FTP objects

FTP

set_debuglevel()

connect()

getwelcome()

login()

abort()

sendcmd()

voidcmd()

retrbinary()

retrlines()

set_pasv()

storbinary()

storlines()

transfercmd()

ntransfercmd()

mlsd()

nlst()

dir()

rename()

delete()

cwd()

mkd()

pwd()

rmd()

size()

quit()

close()

FTP_TLS objects

FTP_TLS

ssl_version

auth()

ccc()

prot_p()

prot_c()

Module variables

error_reply

error_temp

error_perm

error_proto

all_errors

poplib — POP3 protocol client

POP3

POP3_SSL

error_proto

POP3 객체

set_debuglevel()

getwelcome()

capa()

user()

pass_()

apop()

rpop()

stat()

list()

retr()

dele()

rset()

noop()

quit()

top()

uidl()

utf8()

stls()

POP3 예제

imaplib — IMAP4 protocol client

IMAP4

error

abort

readonly

IMAP4_SSL

IMAP4_stream

Internaldate2tuple()

Int2AP()

ParseFlags()

Time2Internaldate()

IMAP4 객체

append()

authenticate()

check()

close()

copy()

create()

delete()

deleteacl()

enable()

expunge()

fetch()

getacl()

getannotation()

getquota()

getquotaroot()

list()

login()

login_cram_md5()

logout()

lsub()

myrights()

namespace()

noop()

open()

partial()

proxyauth()

read()

readline()

recent()

rename()

response()

search()

select()

send()

setacl()

setannotation()

setquota()

shutdown()

socket()

sort()

starttls()

status()

store()

subscribe()

thread()

uid()

unsubscribe()

unselect()

xatom()

PROTOCOL_VERSION

debug

utf8_enabled

IMAP4 예

smtplib — SMTP protocol client

SMTP

SMTP_SSL

LMTP

SMTPException

SMTPServerDisconnected

SMTPResponseException

SMTPSenderRefused

SMTPRecipientsRefused

SMTPDataError

SMTPConnectError

SMTPHeloError

SMTPNotSupportedError

SMTPAuthenticationError

SMTP 객체

set_debuglevel()

docmd()

connect()

helo()

ehlo()

ehlo_or_helo_if_needed()

has_extn()

verify()

login()

auth()

starttls()

sendmail()

send_message()

quit()

SMTP 예

uuid — UUID objects according to RFC 9562

SafeUUID

safe

unsafe

unknown

UUID

bytes

bytes_le

fields

time_low

time_mid

time_hi_version

clock_seq_hi_variant

clock_seq_low

node

time

clock_seq

hex

int

urn

variant

version

is_safe

getnode()

uuid1()

uuid3()

uuid4()

uuid5()

uuid8()

NAMESPACE_DNS

NAMESPACE_URL

NAMESPACE_OID

NAMESPACE_X500

RESERVED_NCS

RFC_4122

RESERVED_MICROSOFT

RESERVED_FUTURE

Command-Line Usage

예제

Command-Line Example

socketserver — A framework for network servers

TCPServer

UDPServer

UnixStreamServer

UnixDatagramServer

서버 생성 노트

ForkingMixIn

ThreadingMixIn

block_on_close

max_children

daemon_threads

ForkingTCPServer

ForkingUDPServer

ThreadingTCPServer

ThreadingUDPServer

ForkingUnixStreamServer

ForkingUnixDatagramServer

ThreadingUnixStreamServer

ThreadingUnixDatagramServer

서버 객체

BaseServer

fileno()

handle_request()

serve_forever()

service_actions()

shutdown()

server_close()

address_family

RequestHandlerClass

server_address

socket

allow_reuse_address

request_queue_size

socket_type

timeout

finish_request()

get_request()

handle_error()

handle_timeout()

process_request()

server_activate()

server_bind()

verify_request()

요청 처리기 객체

BaseRequestHandler

setup()

handle()

finish()

request

client_address

server

StreamRequestHandler

DatagramRequestHandler

rfile

wfile

예

socketserver.TCPServer 예

socketserver.UDPServer 예

비동기 믹스인

http.server — HTTP servers

HTTPServer

ThreadingHTTPServer

BaseHTTPRequestHandler

client_address

server

close_connection

requestline

command

path

request_version

headers

rfile

wfile

server_version

sys_version

error_message_format

error_content_type

protocol_version

MessageClass

responses

handle()

handle_one_request()

handle_expect_100()

send_error()

send_response()

send_header()

send_response_only()

end_headers()

flush_headers()

log_request()

log_error()

log_message()

version_string()

date_time_string()

log_date_time_string()

address_string()

SimpleHTTPRequestHandler

server_version

extensions_map

do_HEAD()

do_GET()

CGIHTTPRequestHandler

cgi_directories

do_POST()

Security Considerations

http.cookies — HTTP state management

CookieError

BaseCookie

SimpleCookie

쿠키 객체

value_decode()

value_encode()

output()

js_output()

load()

Morsel 객체

Morsel

expires

path

comment

domain

secure

version

httponly

samesite

value

coded_value

key

set()

isReservedKey()

output()

js_output()

OutputString()

update()

copy()

setdefault()

예제

http.cookiejar — Cookie handling for HTTP clients

LoadError

CookieJar

FileCookieJar

CookiePolicy

DefaultCookiePolicy

Cookie

CookieJar와 FileCookieJar 객체

add_cookie_header()

extract_cookies()

set_policy()

make_cookies()

set_cookie_if_ok()

set_cookie()

clear()

clear_session_cookies()

save()

load()

revert()

filename

delayload

FileCookieJar 서브 클래스와 웹 브라우저와의 협력

MozillaCookieJar

LWPCookieJar

CookiePolicy 객체

set_ok()

return_ok()

domain_return_ok()

path_return_ok()

netscape

rfc2965

hide_cookie2

DefaultCookiePolicy 객체

blocked_domains()

set_blocked_domains()

is_blocked()

allowed_domains()

set_allowed_domains()

is_not_allowed()

rfc2109_as_netscape

strict_domain

strict_rfc2965_unverifiable

strict_ns_unverifiable

strict_ns_domain

strict_ns_set_initial_dollar

strict_ns_set_path

DomainStrictNoDots

DomainStrictNonDomain

DomainRFC2965Match

DomainLiberal

DomainStrict

Cookie 객체

version

name

value

port

domain

path

secure

expires

discard

comment

comment_url

rfc2109

port_specified

domain_specified

domain_initial_dot

has_nonstandard_attr()

get_nonstandard_attr()

set_nonstandard_attr()

is_expired()

예

xmlrpc — XMLRPC server and client modules

xmlrpc.client — XML-RPC client access

ServerProxy

ServerProxy 객체

listMethods()

methodSignature()

methodHelp()

DateTime 객체

DateTime

decode()

encode()

Binary 객체

Binary

data

decode()

encode()

Fault 객체

Fault

faultCode

faultString

ProtocolError 객체

ProtocolError

url

errcode

errmsg

headers

MultiCall 객체

MultiCall

편의 함수

dumps()

loads()

클라이언트 사용 예

클라이언트와 서버 사용 예

xmlrpc.server — Basic XML-RPC servers

SimpleXMLRPCServer

CGIXMLRPCRequestHandler

SimpleXMLRPCRequestHandler

SimpleXMLRPCServer 객체

register_function()

register_instance()

register_introspection_functions()

register_multicall_functions()

rpc_paths

SimpleXMLRPCServer 예제

CGIXMLRPCRequestHandler

register_function()

register_instance()

register_introspection_functions()

register_multicall_functions()

handle_request()

XMLRPC 서버 문서화

DocXMLRPCServer

DocCGIXMLRPCRequestHandler

DocXMLRPCRequestHandler

DocXMLRPCServer 객체

set_server_title()

set_server_name()

set_server_documentation()

DocCGIXMLRPCRequestHandler

set_server_title()

set_server_name()

set_server_documentation()

ipaddress — IPv4/IPv6 manipulation library

편의 팩토리 함수

ip_address()

ip_network()

ip_interface()

IP 주소

주소 객체

IPv4Address

version

max_prefixlen

compressed

exploded

packed

reverse_pointer

is_multicast

is_private

is_global

is_unspecified

is_reserved

is_loopback

is_link_local

ipv6_mapped

__format__()

IPv6Address

compressed

exploded

packed

reverse_pointer

version

max_prefixlen

is_multicast

is_private

is_global

is_unspecified

is_reserved

is_loopback

is_link_local

is_site_local

ipv4_mapped

scope_id

sixtofour

teredo

__format__()

문자열과 정수로의 변환

연산자

비교 연산자

산술 연산자

IP 네트워크 정의

접두사, 네트 마스크 및 호스트 마스크

네트워크 객체

IPv4Network

version

max_prefixlen

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

network_address

broadcast_address

hostmask

netmask

with_prefixlen

compressed

exploded

with_netmask

with_hostmask

num_addresses

prefixlen

hosts()

overlaps()

address_exclude()

subnets()

supernet()

subnet_of()

supernet_of()

compare_networks()

IPv6Network

version

max_prefixlen

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

network_address

broadcast_address

hostmask

netmask

with_prefixlen

compressed

exploded

with_netmask

with_hostmask

num_addresses

prefixlen

hosts()

overlaps()

address_exclude()

subnets()

supernet()

subnet_of()

supernet_of()

compare_networks()

is_site_local

연산자

논리 연산자

이터레이션

주소 컨테이너로서의 네트워크

인터페이스 객체

IPv4Interface

ip

network

with_prefixlen

with_netmask

with_hostmask

IPv6Interface

ip

network

with_prefixlen

with_netmask

with_hostmask

연산자

논리 연산자

다른 모듈 수준 함수

v4_int_to_packed()

v6_int_to_packed()

summarize_address_range()

collapse_addresses()

get_mixed_type_key()

맞춤 예외

AddressValueError

NetmaskValueError

webbrowser — Convenient web-browser controller

소스 코드: Lib/webbrowser.py [https://github.com/python/cpython/tree/main/Lib/webbrowser.py]

The webbrowser module provides a high-level interface to allow displaying web-based documents to users. Under most circumstances, simply calling the open() function from this module will do the right thing.

유닉스에서, X11에서는 그래픽 브라우저가 선호되지만, 그래픽 브라우저를 사용할 수 없거나 X11 디스플레이를 사용할 수 없으면 텍스트 모드 브라우저가 사용됩니다. 텍스트 모드 브라우저가 사용되면, 사용자가 브라우저를 종료할 때까지 호출하는 프로세스가 블록 됩니다.

환경 변수 BROWSER가 있으면, 플랫폼 기본값보다 먼저 시도하기 위해 os.pathsep으로 구분된 브라우저 목록으로 해석됩니다. 목록 부분의 값에 문자열 %s가 포함되어 있으면, %s를 인자 URL로 치환해서 만들어지는 리터럴 브라우저 명령 줄로 해석됩니다; 부분이 %s를 포함하지 않으면, 단순히 시작할 브라우저의 이름으로 해석됩니다. [1]

유닉스가 아닌 플랫폼에서, 또는 유닉스에서 원격 브라우저를 사용할 수 있을 때, 제어하는 프로세스는 사용자가 브라우저를 완료할 때까지 기다리지 않고, 원격 브라우저가 디스플레이에 자체 창을 유지하도록 허용합니다. 유닉스에서 원격 브라우저를 사용할 수 없으면, 제어하는 프로세스가 새 브라우저를 시작하고 기다랍니다.

On iOS, the BROWSER environment variable, as well as any arguments controlling autoraise, browser preference, and new tab/window creation will be ignored. Web pages will always be opened in the user’s preferred browser, in a new tab, with the browser being brought to the foreground. The use of the webbrowser module on iOS requires the ctypes module. If ctypes isn’t available, calls to open() will fail.

The script webbrowser can be used as a command-line interface for the module. It accepts a URL as the argument. It accepts the following optional parameters:

-n/--new-window opens the URL in a new browser window, if possible.

-t/--new-tab opens the URL in a new browser page (“tab”).

The options are, naturally, mutually exclusive. Usage example:

python -m webbrowser -t "https://www.python.org"

Availability: not WASI, not Android.

다음 예외가 정의됩니다:

exception webbrowser.Error

브라우저 제어 에러가 일어날 때 발생하는 예외.

다음 함수가 정의됩니다:

webbrowser.open(url, new=0, autoraise=True)

기본 브라우저를 사용하여 url을 표시합니다. new가 0이면, 가능하다면 같은 브라우저 창에서 url이 열립니다. new가 1이면, 가능하다면 새 브라우저 창이 열립니다. new가 2이면, 가능하다면 새 브라우저 페이지(“탭”)가 열립니다. autoraise가 True이면, 가능하다면 창을 올립니다(raise) (이것은 많은 창 관리자에서 이 변수의 설정과 관계없이 일어납니다).

Returns True if a browser was successfully launched, False otherwise.

일부 플랫폼에서, 이 함수를 사용하여 파일명을 여는 것은 동작하고 운영 체제의 연결된 프로그램이 시작될 수 있습니다. 하지만, 이것은 지원되지도 이식성 있지도 않습니다.

인자 url로 감사 이벤트(auditing event) webbrowser.open을 발생시킵니다.

webbrowser.open_new(url)

가능하다면, 기본 브라우저의 새 창에서 url을 엽니다, 그렇지 않으면, 유일한 브라우저 창에서 url을 엽니다.

Returns True if a browser was successfully launched, False otherwise.

webbrowser.open_new_tab(url)

가능하다면, 기본 브라우저의 새 페이지(“탭”)에서 url을 엽니다, 그렇지 않으면 open_new()와 동등합니다.

Returns True if a browser was successfully launched, False otherwise.

webbrowser.get(using=None)

브라우저 유형 using에 대한 제어기 객체를 반환합니다. using이 None이면, 호출자의 환경에 적합한 기본 브라우저을 위한 제어기 객체를 반환합니다.

webbrowser.register(name, constructor, instance=None, *, preferred=False)

브라우저 유형 name을 등록합니다. 일단 브라우저 유형이 등록되면, get() 함수는 해당 브라우저 유형에 대한 제어기를 반환할 수 있습니다. instance가 제공되지 않거나, None이면, 필요할 때 constructor가 매개 변수 없이 호출되어 인스턴스를 만듭니다. instance가 제공되면, constructor는 절대로 호출되지 않으며, None일 수 있습니다.

preferred를 True로 설정하면 이 브라우저를 인자 없이 get()을 호출할 때 선호되는 결과가 되도록 합니다. 그렇지 않으면, 이 엔트리 포인트는 BROWSER 변수를 설정하거나 선언한 처리기의 이름과 일치하는 비어 있지 않은 인자로 get()을 호출하려는 경우에만 유용합니다.

버전 3.7에서 변경: preferred 키워드 전용 매개 변수가 추가되었습니다.

여러 가지 브라우저 유형이 미리 정의되어 있습니다. 이 표는 get() 함수로 전달될 수 있는 유형 이름과 제어기 클래스의 해당 인스턴스 화를 제공합니다, 모두 이 모듈에서 정의됩니다.

유형 이름

클래스 이름

노트

'mozilla'

Mozilla('mozilla')

'firefox'

Mozilla('mozilla')

'epiphany'

Epiphany('epiphany')

'kfmclient'

Konqueror()

(1)

'konqueror'

Konqueror()

(1)

'kfm'

Konqueror()

(1)

'opera'

Opera()

'links'

GenericBrowser('links')

'elinks'

Elinks('elinks')

'lynx'

GenericBrowser('lynx')

'w3m'

GenericBrowser('w3m')

'windows-default'

WindowsDefault

(2)

'macosx'

MacOSXOSAScript('default')

(3)

'safari'

MacOSXOSAScript('safari')

(3)

'google-chrome'

Chrome('google-chrome')

'chrome'

Chrome('chrome')

'chromium'

Chromium('chromium')

'chromium-browser'

Chromium('chromium-browser')

'iosbrowser'

IOSBrowser

(4)

노트:

“Konqueror” is the file manager for the KDE desktop environment for Unix, and only makes sense to use if KDE is running. Some way of reliably detecting KDE would be nice; the KDEDIR variable is not sufficient. Note also that the name “kfm” is used even when using the konqueror command with KDE 2 — the implementation selects the best strategy for running Konqueror.

윈도우 플랫폼에서만.

Only on macOS.

Only on iOS.

Added in version 3.2: A new MacOSXOSAScript class has been added and is used on Mac instead of the previous MacOSX class. This adds support for opening browsers not currently set as the OS default.

Added in version 3.3: Chrome/Chromium에 대한 지원이 추가되었습니다.

버전 3.12에서 변경: Support for several obsolete browsers has been removed. Removed browsers include Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, and Firefox versions 35 and below.

버전 3.13에서 변경: Support for iOS has been added.

여기 몇 가지 간단한 예제가 있습니다:

url = 'https://docs.python.org/'

# Open URL in a new tab, if a browser window is already open.
webbrowser.open_new_tab(url)

# Open URL in new window, raising the window if possible.
webbrowser.open_new(url)

브라우저 제어기 객체

브라우저 제어기는 세 가지 모듈 수준의 편리 함수와 평행하게 다음과 같은 메서드를 제공합니다:

controller.name

System-dependent name for the browser.

controller.open(url, new=0, autoraise=True)

이 제어기가 처리하는 브라우저를 사용하여 url을 표시합니다. new가 1이면, 가능하다면 새 브라우저 창이 열립니다. new가 2이면, 가능하다면 새 브라우저 페이지(“탭”)가 열립니다.

controller.open_new(url)

가능하다면, 이 제어기가 처리하는 브라우저의 새 창에 url을 엽니다, 그렇지 않으면, 유일한 브라우저 창에 url을 엽니다. 별칭 open_new().

controller.open_new_tab(url)

가능하다면, 이 제어기가 처리하는 브라우저의 새 페이지(“탭”)에 url을 엽니다, 그렇지 않으면 open_new()와 동등합니다.

각주

[1]

전체 경로 없이 여기에서 명명된 실행 파일은 PATH 환경 변수에 지정된 디렉터리에서 검색됩니다.

wsgiref — WSGI Utilities and Reference Implementation

Source code: Lib/wsgiref [https://github.com/python/cpython/tree/main/Lib/wsgiref]

WSGI(Web Server Gateway Interface)는 웹 서버 소프트웨어와 파이썬으로 작성된 웹 응용 프로그램 간의 표준 인터페이스입니다. 표준 인터페이스는 여러 웹 서버에서 WSGI를 지원하는 응용 프로그램을 쉽게 사용할 수 있도록 합니다.

웹 서버와 프로그래밍 프레임워크의 작성자만 WSGI 설계의 모든 세부 사항과 코너 케이스를 알 필요가 있습니다. 단지 WSGI 응용 프로그램을 설치하거나 기존 프레임워크를 사용하여 웹 응용 프로그램을 작성하기 위해, WSGI의 모든 세부 사항을 이해할 필요는 없습니다.

wsgiref is a reference implementation of the WSGI specification that can be used to add WSGI support to a web server or framework. It provides utilities for manipulating WSGI environment variables and response headers, base classes for implementing WSGI servers, a demo HTTP server that serves WSGI applications, types for static type checking, and a validation tool that checks WSGI servers and applications for conformance to the WSGI specification (PEP 3333 [https://peps.python.org/pep-3333/]).

WSGI에 대한 더 자세한 정보 및 자습서와 기타 자원에 대한 링크는 wsgi.readthedocs.io [https://wsgi.readthedocs.io/]를 참조하십시오.

wsgiref.util – WSGI 환경 유틸리티

This module provides a variety of utility functions for working with WSGI environments. A WSGI environment is a dictionary containing HTTP request variables as described in PEP 3333 [https://peps.python.org/pep-3333/]. All of the functions taking an environ parameter expect a WSGI-compliant dictionary to be supplied; please see PEP 3333 [https://peps.python.org/pep-3333/] for a detailed specification and WSGIEnvironment for a type alias that can be used in type annotations.

wsgiref.util.guess_scheme(environ)

environ 딕셔너리에서 HTTPS 환경 변수를 검사하여 wsgi.url_scheme이 “http”와 “https” 중 어느 것인지 추측합니다. 반환 값은 문자열입니다.

이 함수는 CGI 나 FastCGI와 같은 CGI와 유사한 프로토콜을 감싸는 게이트웨이를 만들 때 유용합니다. 일반적으로, 이러한 프로토콜을 제공하는 서버는 SSL을 통해 요청이 수신될 때 “1”, “yes” 또는 “on” 값을 갖는 HTTPS 변수를 포함합니다. 따라서, 이 함수는 그런 값을 발견하면 “https”를 반환하고, 그렇지 않으면 “http”를 반환합니다.

wsgiref.util.request_uri(environ, include_query=True)

PEP 3333 [https://peps.python.org/pep-3333/]의 “URL 재구성” 절에 있는 알고리즘을 사용하여 전체 요청 URI를 반환합니다. 선택적으로 질의 문자열(query string)을 포함합니다. include_query가 거짓이면 질의 문자열은 결과 URI에 포함되지 않습니다.

wsgiref.util.application_uri(environ)

PATH_INFO 와 QUERY_STRING 변수가 무시된다는 점을 제외하면 request_uri()와 유사합니다. 결과는 요청이 가리키는 응용 프로그램 객체의 기본 URI입니다.

wsgiref.util.shift_path_info(environ)

단일 이름을 PATH_INFO에서 SCRIPT_NAME로 이동하고 이름을 반환합니다. environ 딕셔너리는 그 자리에서 수정됩니다; 원본 PATH_INFO 나 SCRIPT_NAME를 그대로 유지해야 하면 사본을 사용하십시오.

PATH_INFO에 남아있는 경로 세그먼트가 없으면, None이 반환됩니다.

일반적으로, 이 루틴은 요청 URI 경로의 각 부분을 처리하는 데 사용됩니다, 예를 들어 경로를 일련의 딕셔너리 키로 취급합니다. 이 루틴은 전달된 환경을 수정하여 대상 URI에 있는 다른 WSGI 응용 프로그램을 호출하는 데 적합하게 만듭니다. 예를 들어, /foo에 WSGI 응용 프로그램이 있고, 요청 URI 경로가 /foo/bar/baz이고, /foo의 WSGI 응용 프로그램이 shift_path_info()를 호출하면 “bar” 문자열을 수신하고 전달할 환경이 /foo/bar에 있는 WSGI 응용 프로그램에 전달하기 적합하도록 갱신됩니다. 즉, SCRIPT_NAME는 /foo에서 /foo/bar로 변경되고, PATH_INFO는 /bar/baz에서 /baz로 변경됩니다.

PATH_INFO가 단지 “/”일 때, 이 루틴은 빈 문자열을 반환하고 SCRIPT_NAME에 후행 슬래시를 추가합니다; 빈 경로 세그먼트는 일반적으로 무시되고, SCRIPT_NAME는 일반적으로 슬래시로 끝나지 않음에도 그렇게 합니다. 의도적인 동작입니다. 이 루틴을 사용하여 객체를 탐색할 때, 응용 프로그램이 /x로 끝나는 URI와 /x/로 끝나는 URI의 차이를 구별할 수 있도록 하기 위함입니다.

wsgiref.util.setup_testing_defaults(environ)

테스트 목적으로 environ를 뻔한 기본값으로 갱신합니다.

이 루틴은 HTTP_HOST, SERVER_NAME, SERVER_PORT, REQUEST_METHOD, SCRIPT_NAME, PATH_INFO 및 모든 PEP 3333 [https://peps.python.org/pep-3333/]에서 정의된 wsgi.* 변수를 포함하여 WSGI에 필요한 다양한 매개 변수를 추가합니다. 기본값만 제공하며, 이 변수들에 대한 기존 설정을 대체하지 않습니다.

이 루틴은 WSGI 서버와 응용 프로그램의 단위 테스트가 더미 환경을 쉽게 설정하도록 하기 위한 것입니다. 데이터가 가짜이므로, 실제 WSGI 서버나 응용 프로그램에서 사용해서는 안 됩니다!

사용 예:

from wsgiref.util import setup_testing_defaults
from wsgiref.simple_server import make_server

# A relatively simple WSGI application. It's going to print out the
# environment dictionary after being updated by setup_testing_defaults
def simple_app(environ, start_response):
    setup_testing_defaults(environ)

    status = '200 OK'
    headers = [('Content-type', 'text/plain; charset=utf-8')]

    start_response(status, headers)

    ret = [("%s: %s\n" % (key, value)).encode("utf-8")
           for key, value in environ.items()]
    return ret

with make_server('', 8000, simple_app) as httpd:
    print("Serving on port 8000...")
    httpd.serve_forever()

위의 환경 함수 외에도, wsgiref.util 모듈은 다음과 같은 기타 유틸리티를 제공합니다:

wsgiref.util.is_hop_by_hop(header_name)

‘header_name’이 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]가 정의하고 있는 HTTP/1.1 “Hop-by-Hop” 헤더면 True를 반환합니다.

class wsgiref.util.FileWrapper(filelike, blksize=8192)

A concrete implementation of the wsgiref.types.FileWrapper protocol used to convert a file-like object to an iterator. The resulting objects are iterables. As the object is iterated over, the optional blksize parameter will be repeatedly passed to the filelike object’s read() method to obtain bytestrings to yield. When read() returns an empty bytestring, iteration is ended and is not resumable.

filelike에 close() 메서드가 있으면, 반환된 객체에도 close() 메서드가 있고, 호출될 때 filelike 객체의 close() 메서드를 호출합니다.

사용 예:

from io import StringIO
from wsgiref.util import FileWrapper

# We're using a StringIO-buffer for as the file-like object
filelike = StringIO("This is an example file-like object"*10)
wrapper = FileWrapper(filelike, blksize=5)

for chunk in wrapper:
    print(chunk)

버전 3.11에서 변경: Support for __getitem__() method has been removed.

wsgiref.headers – WSGI 응답 헤더 도구

이 모듈은 매핑류 인터페이스를 사용하여 WSGI 응답 헤더를 편리하게 조작할 수 있는 클래스 Headers 하나를 제공합니다.

class wsgiref.headers.Headers([headers])

PEP 3333 [https://peps.python.org/pep-3333/]에 설명된 것처럼 헤더 이름/값 튜플의 리스트이어야 하는 headers를 감싸는 매핑류 객체를 만듭니다. headers의 기본값은 빈 리스트입니다.

Headers objects support typical mapping operations including __getitem__(), get(), __setitem__(), setdefault(), __delitem__() and __contains__(). For each of these methods, the key is the header name (treated case-insensitively), and the value is the first value associated with that header name. Setting a header deletes any existing values for that header, then adds a new value at the end of the wrapped header list. Headers’ existing order is generally maintained, with new headers added to the end of the wrapped list.

딕셔너리와 달리, Headers 객체는 감싸진 헤더 리스트에 없는 키를 가져오거나 삭제하려고 하면 에러를 발생시키지 않습니다. 존재하지 않는 헤더를 가져오려고 하면 None을 반환하고, 존재하지 않는 헤더를 삭제하면 아무것도 하지 않습니다.

Headers 객체는 keys(), values() 및 items() 메서드도 지원합니다. keys() 와 items()에 의해 반환된 리스트에는 다중-값 헤더가 있으면 같은 키가 두 번 이상 포함될 수 있습니다. Headers 객체의 len()는 items()의 길이와 같고, 이는 감싸진 헤더 리스트의 길이와 같습니다. 실제로, items() 메서드는 단지 감싸진 헤더 리스트의 복사본을 반환합니다.

Headers 객체에서 bytes()를 호출하면 HTTP 응답 헤더로 전송하기에 적합한 포맷된 바이트열이 반환됩니다. 각 헤더는 콜론과 공백으로 구분된 값과 함께 줄에 들어갑니다. 각 줄은 캐리지 리턴과 줄넘김으로 끝나며, 바이트열은 빈 줄로 끝납니다.

Headers 객체는 매핑 인터페이스와 포매팅 기능 외에도, 다중-값 헤더를 조회하거나 추가하고, MIME 파라미터가 있는 헤더를 추가하기 위해 다음과 같은 메서드를 제공합니다:

get_all(name)

주어진 이름의 헤더에 대한 모든 값의 리스트를 반환합니다.

반환된 리스트는 원래 헤더 리스트에 나타나거나 이 인스턴스에 추가된 순서대로 정렬되고, 중복을 포함할 수 있습니다. 삭제되고 다시 삽입된 필드는 항상 헤더 리스트의 끝에 추가됩니다. 주어진 이름의 필드가 존재하지 않으면, 빈 리스트를 반환합니다.

add_header(name, value, **_params)

키워드 인자로 지정되는 선택적 MIME 파라미터와 함께 헤더를 추가합니다 (다중-값 가능).

name은 추가할 헤더 필드입니다. 키워드 인자는 헤더 필드에 대한 MIME 파라미터를 설정하는 데 사용될 수 있습니다. 각 파라미터는 문자열이나 None 이어야 합니다. 파라미터 이름의 밑줄은 대시로 변환됩니다; 파이썬 식별자에서는 대시가 유효하지 않지만 많은 MIME 파라미터 이름에는 대시가 포함되기 때문입니다. 파라미터값이 문자열이면 name="value" 형식으로 헤더 값 파라미터에 추가됩니다. None이면 파라미터 이름 만 추가됩니다. (이것은 값이 없는 MIME 파라미터에 사용됩니다.) 사용 예:

h.add_header('content-disposition', 'attachment', filename='bud.gif')

위의 코드는 다음과 같은 헤더를 추가합니다:

Content-Disposition: attachment; filename="bud.gif"

버전 3.5에서 변경: headers 매개 변수는 선택적입니다.

wsgiref.simple_server – 간단한 WSGI HTTP 서버

이 모듈은 WSGI 응용 프로그램을 서빙하는 간단한 HTTP 서버(http.server 기반)를 구현합니다. 각 서버 인스턴스는 주어진 호스트와 포트에서 단일 WSGI 응용 프로그램을 서빙합니다. 단일 호스트와 포트에서 여러 응용 프로그램을 서빙하려면, PATH_INFO를 구문 분석하여 각 요청에 대해 호출할 응용 프로그램을 선택하는 WSGI 응용 프로그램을 만들어야 합니다. (예를 들어, wsgiref.util의 shift_path_info() 함수를 사용해서.)

wsgiref.simple_server.make_server(host, port, app, server_class=WSGIServer, handler_class=WSGIRequestHandler)

host 와 port에서 수신을 기다리고, app에 대한 연결을 수락하는 새 WSGI 서버를 만듭니다. 반환 값은 제공된 server_class의 인스턴스이며, 지정된 handler_class를 사용하여 요청을 처리합니다. app는 PEP 3333 [https://peps.python.org/pep-3333/]에 정의된 WSGI 응용 프로그램 객체여야 합니다.

사용 예:

from wsgiref.simple_server import make_server, demo_app

with make_server('', 8000, demo_app) as httpd:
    print("Serving HTTP on port 8000...")

    # Respond to requests until process is killed
    httpd.serve_forever()

    # Alternative: serve one request, then exit
    httpd.handle_request()

wsgiref.simple_server.demo_app(environ, start_response)

이 함수는 작지만 완벽한 WSGI 응용 프로그램인데, “Hello world!” 메시지와 environ 매개 변수에 제공된 키/값 쌍 목록이 포함된 텍스트 페이지를 반환합니다. WSGI 서버(가령 wsgiref.simple_server)가 간단한 WSGI 응용 프로그램을 올바르게 실행할 수 있는지 확인하는 데 유용합니다.

class wsgiref.simple_server.WSGIServer(server_address, RequestHandlerClass)

WSGIServer 인스턴스를 만듭니다. server_address는 (host,port) 튜플이어야 하며, RequestHandlerClass는 http.server.BaseHTTPRequestHandler의 서브 클래스여야 하는데, 요청을 처리하는 데 사용됩니다.

make_server() 함수가 모든 세부 사항을 처리할 수 있으므로, 일반적으로 이 생성자를 호출할 필요가 없습니다.

WSGIServer는 http.server.HTTPServer의 서브 클래스이므로, 모든 메서드(가령 serve_forever()와 handle_request())를 사용할 수 있습니다. WSGIServer는 또한 다음과 같은 WSGI 전용 메서드를 제공합니다:

set_app(application)

콜러블 application을 요청을 수신하는 WSGI 응용 프로그램으로 설정합니다.

get_app()

Returns the currently set application callable.

그러나 일반적으로, 이러한 추가 메서드를 사용할 필요가 없는데, set_app()는 일반적으로 make_server()에서 호출되고, get_app()은 주로 요청 처리기 인스턴스의 필요를 위해 존재하기 때문입니다

class wsgiref.simple_server.WSGIRequestHandler(request, client_address, server)

지정된 request (즉, 소켓), client_address ((host,port) 튜플) 및 server (WSGIServer 인스턴스)를 위한 HTTP 처리기를 만듭니다.

이 클래스의 인스턴스를 직접 만들 필요는 없습니다; WSGIServer 객체가 필요에 따라 자동으로 만듭니다. 그러나, 이 클래스를 서브 클래싱하여 handler_class로 make_server() 함수에 제공할 수 있습니다. 서브 클래스에서 재정의하는데 적합한 메서드들은 다음과 같습니다:

get_environ()

Return a WSGIEnvironment dictionary for a request. The default implementation copies the contents of the WSGIServer object’s base_environ dictionary attribute and then adds various headers derived from the HTTP request. Each call to this method should return a new dictionary containing all of the relevant CGI environment variables as specified in PEP 3333 [https://peps.python.org/pep-3333/].

get_stderr()

wsgi.errors 스트림으로 사용해야 하는 객체를 반환합니다. 기본 구현은 단지 sys.stderr를 반환합니다.

handle()

HTTP 요청을 처리합니다. 기본 구현은 wsgiref.handlers 클래스를 사용하여 실제 WSGI 응용 프로그램 인터페이스를 구현하는 처리기 인스턴스를 만듭니다.

wsgiref.validate — WSGI 적합성 검사기

새로운 WSGI 응용 프로그램 객체, 프레임워크, 서버 또는 미들웨어를 만들 때, wsgiref.validate를 사용하여 새 코드의 적합성을 확인하는 것이 유용할 수 있습니다. 이 모듈은 WSGI 서버나 게이트웨이와 WSGI 응용 프로그램 객체 사이의 통신을 검증하는 WSGI 응용 프로그램 객체를 만드는 함수를 제공하여, 양측의 프로토콜 준수 여부를 검사할 수 있도록 합니다.

이 유틸리티는 완전한 PEP 3333 [https://peps.python.org/pep-3333/] 적합성을 보장하지는 않습니다; 이 모듈에서 에러가 없다고 해서 에러가 존재하지 않는다는 것을 의미하지는 않습니다. 그러나, 이 모듈에서 오류가 발생하면, 서버나 응용 프로그램이 100% 적합하지 않다는 것은 사실상 확실합니다.

이 모듈은 Ian Bicking의 “Python Paste” 라이브러리의 paste.lint 모듈을 기반으로 합니다.

wsgiref.validate.validator(application)

application 감싸고 새 WSGI 응용 프로그램 객체를 반환합니다. 반환된 응용 프로그램은 모든 요청을 원래 application으로 전달하고, application과 이를 호출하는 서버가 모두 WSGI 명세와 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]를 준수하는지 확인합니다.

탐지된 모든 부적합 결과는 AssertionError를 일으킵니다; 그러나 이러한 에러를 처리하는 방법은 서버에 따라 다릅니다. 예를 들어, wsgiref.simple_server와 wsgiref.handlers를 기반으로 하는 다른 (에러 처리 메서드를 재정의해서 다른 작업을 수행하지 않는) 서버는 단순히 에러가 발생했다는 메시지를 출력하고 sys.stderr 나 기타 에러 스트림으로 트레이스백을 덤프합니다.

이 래퍼는 의심스럽기는 하지만 PEP 3333 [https://peps.python.org/pep-3333/]에서 실제로 금지되지 않을 수도 있는 동작을 나타내도록 warnings 모듈을 사용하여 출력을 생성할 수도 있습니다. 파이썬 명령 줄 옵션이나 warnings API를 사용해서 억제되지 않는 한, 그러한 경고는 sys.stderr(같은 객체가 아니라면 wsgi.errors가 아닙니다)에 기록됩니다.

사용 예:

from wsgiref.validate import validator
from wsgiref.simple_server import make_server

# Our callable object which is intentionally not compliant to the
# standard, so the validator is going to break
def simple_app(environ, start_response):
    status = '200 OK'  # HTTP Status
    headers = [('Content-type', 'text/plain')]  # HTTP Headers
    start_response(status, headers)

    # This is going to break because we need to return a list, and
    # the validator is going to inform us
    return b"Hello World"

# This is the application wrapped in a validator
validator_app = validator(simple_app)

with make_server('', 8000, validator_app) as httpd:
    print("Listening on port 8000....")
    httpd.serve_forever()

wsgiref.handlers – 서버/게이트웨이 베이스 클래스

이 모듈은 WSGI 서버와 게이트웨이를 구현하기 위한 베이스 처리기 클래스를 제공합니다. 이러한 베이스 클래스는 입력, 출력 및 에러 스트림과 함께 CGI와 유사한 환경이 제공되는 한, WSGI 응용 프로그램과 통신하는 대부분 작업을 처리합니다.

class wsgiref.handlers.CGIHandler

sys.stdin, sys.stdout, sys.stderr 및 os.environ를 통한 CGI 기반 호출. 이것은 WSGI 응용 프로그램이 있고 CGI 스크립트로 실행하려고 할 때 유용합니다. CGIHandler().run(app)을 호출하기만 하면 됩니다. 여기서 app은 호출할 WSGI 응용 프로그램 객체입니다.

이 클래스는 wsgi.run_once를 참으로, wsgi.multithread를 거짓으로, wsgi.multiprocess를 참으로 설정하고, 필요한 CGI 스트림과 환경을 얻기 위해 항상 sys와 os를 사용하는 BaseCGIHandler의 서브 클래스입니다.

class wsgiref.handlers.IISCGIHandler

config allowPathInfo 옵션 (IIS>=7) 나 metabase allowPathInfoForScriptMappings (IIS<7)를 설정하지 않고도, Microsoft IIS 웹 서버에 배포할 때 사용할 수 있는 CGIHandler의 특수한 대안.

기본적으로, IIS는 앞에 SCRIPT_NAME이 중복된 PATH_INFO를 제공하므로, 라우팅을 구현하려는 WSGI 응용 프로그램에 문제가 발생합니다. 이 처리기는 중복된 경로를 제거합니다.

IIS가 올바른 PATH_INFO를 전달하도록 구성할 수 있지만, PATH_TRANSLATED가 잘못되는 다른 버그가 발생합니다. 다행히도 이 변수는 거의 사용되지 않으며 WSGI에서 보장하지 않습니다. 그러나 IIS<7에서는 설정이 가상 호스트 수준에서만 이루어지므로, 다른 모든 스크립트 매핑에 영향을 미치며, 그중 많은 것들이 PATH_TRANSLATED 버그에 노출되면 망가집니다. 이러한 이유로 IIS<7은 거의 수정해서 배포되지 않습니다 (아직도 UI가 없어서 IIS7 조차도 거의 사용하지 않습니다.).

CGI 코드가 옵션이 설정되었는지를 알 수 있는 방법이 없으므로, 별도의 처리기 클래스가 제공됩니다. CGIHandler와 같은 방식으로 사용됩니다. 즉, IISCGIHandler().run(app)을 호출합니다. 여기서 app은 호출할 WSGI 응용 프로그램 객체입니다.

Added in version 3.2.

class wsgiref.handlers.BaseCGIHandler(stdin, stdout, stderr, environ, multithread=True, multiprocess=False)

CGIHandler와 유사하지만, sys 와 os 모듈을 사용하는 대신, CGI 환경과 I/O 스트림이 명시적으로 지정됩니다. multithread 와 multiprocess 값은 처리기 인스턴스가 실행하는 모든 응용 프로그램에 대한 wsgi.multithread 와 wsgi.multiprocess 플래그를 설정하는 데 사용됩니다.

이 클래스는 HTTP “오리진 서버” 이외의 소프트웨어에서 사용하기 위한 SimpleHandler의 서브 클래스입니다. HTTP 상태를 보내기 위해 Status: 헤더를 사용하는 게이트웨이 프로토콜 구현(가령 CGI, FastCGI, SCGI 등)을 작성하는 경우 SimpleHandler 대신 이것을 서브 클래싱하고 싶을 겁니다.

class wsgiref.handlers.SimpleHandler(stdin, stdout, stderr, environ, multithread=True, multiprocess=False)

BaseCGIHandler와 유사하지만, HTTP 오리진 서버에 사용하도록 설계되었습니다. HTTP 서버 구현을 작성하는 경우 BaseCGIHandler 대신 이것을 서브 클래싱하고 싶을 겁니다.

This class is a subclass of BaseHandler. It overrides the __init__(), get_stdin(), get_stderr(), add_cgi_vars(), _write(), and _flush() methods to support explicitly setting the environment and streams via the constructor. The supplied environment and streams are stored in the stdin, stdout, stderr, and environ attributes.

stdout의 write() 메서드는 io.BufferedIOBase처럼 각 덩어리 전체를 기록해야 합니다.

class wsgiref.handlers.BaseHandler

이것은 WSGI 응용 프로그램을 실행하기 위한 추상 베이스 클래스입니다. 원칙적으로 여러 요청에 대해 재사용할 수 있는 서브 클래스를 만들 수 있지만, 각 인스턴스는 단일 HTTP 요청을 처리합니다.

BaseHandler 인스턴스에는 외부 사용을 위한 하나의 메서드 만 있습니다:

run(app)

지정된 WSGI 응용 프로그램인 app을 실행합니다.

다른 모든 BaseHandler 메서드는 응용 프로그램을 실행하는 과정에서 이 메서드에 의해 호출되므로, 주로 과정을 사용자 정의하기 위해 존재합니다.

다음 메서드는 서브 클래스에서 반드시 재정의되어야 합니다:

_write(data)

클라이언트로의 전송을 위해 바이트열 data를 버퍼링합니다. 이 메서드가 실제로 데이터를 전송해도 상관없습니다; BaseHandler는 쓰기와 플러시 연산을 분리하여 하부 시스템에 실제로 이러한 구분이 있을 때 효율성을 높입니다.

_flush()

버퍼링 된 데이터를 클라이언트로 전송하도록 강제합니다. 이 메서드가 아무 일도 하지 않아도 상관없습니다 (즉, _write()가 실제로 데이터를 보낸다면).

get_stdin()

Return an object compatible with InputStream suitable for use as the wsgi.input of the request currently being processed.

get_stderr()

Return an object compatible with ErrorStream suitable for use as the wsgi.errors of the request currently being processed.

add_cgi_vars()

현재 요청에 대한 CGI 변수를 environ 어트리뷰트에 삽입합니다.

재정의하고 싶을 수 있는 다른 메서드와 어트리뷰트는 다음과 같습니다. 그러나, 이 목록은 요약에 지나지 않고, 재정의할 수 있는 모든 메서드가 포함되어 있지 않습니다. 사용자 정의된 BaseHandler 서브 클래스를 작성하기 전에 독스트링과 소스 코드를 참조하여 추가 정보를 얻어야 합니다.

WSGI 환경을 사용자 정의하기 위한 어트리뷰트와 메서드:

wsgi_multithread

wsgi.multithread 환경 변수에 사용될 값. BaseHandler에서는 기본값이 참이지만, 다른 서브 클래스는 다른 기본값을 가질 수 있습니다 (또는 생성자에 의해 설정될 수 있습니다).

wsgi_multiprocess

wsgi.multiprocess 환경 변수에 사용될 값. BaseHandler에서는 기본값이 참이지만, 다른 서브 클래스는 다른 기본값을 가질 수 있습니다 (또는 생성자에 의해 설정될 수 있습니다).

wsgi_run_once

wsgi.run_once 환경 변수에 사용될 값. BaseHandler에서는 기본값이 거짓이지만, CGIHandler는 기본적으로 참으로 설정합니다.

os_environ

모든 요청의 WSGI 환경에 포함될 기본 환경 변수. 기본적으로, wsgiref.handlers를 임포트 한 시점의 os.environ 사본이지만, 서브 클래스는 클래스나 인스턴스 수준에서 자체적으로 만들 수 있습니다. 기본값이 여러 클래스와 인스턴스 간에 공유되므로, 딕셔너리는 읽기 전용으로 간주해야 합니다.

server_software

origin_server 어트리뷰트가 설정된 경우, 이 어트리뷰트의 값은 기본 SERVER_SOFTWARE WSGI 환경 변수를 설정하는 데 사용되고, HTTP 응답의 기본 Server: 헤더를 설정하는 데도 사용됩니다. HTTP 오리진 서버가 아닌 처리기(가령 BaseCGIHandler 와 CGIHandler)에서는 무시됩니다.

버전 3.3에서 변경: “Python”이라는 용어는 “CPython”, “Jython” 등과 같은 구현 특정 용어로 대체됩니다.

get_scheme()

현재의 요청에 사용되고 있는 URL 스킴을 반환합니다. 기본 구현은 wsgiref.util의 guess_scheme() 함수를 사용하여, 현재 요청의 environ 변수를 기반으로, 스킴이 “http”와 “https” 중 어느 것인지 추측합니다.

setup_environ()

Set the environ attribute to a fully populated WSGI environment. The default implementation uses all of the above methods and attributes, plus the get_stdin(), get_stderr(), and add_cgi_vars() methods and the wsgi_file_wrapper attribute. It also inserts a SERVER_SOFTWARE key if not present, as long as the origin_server attribute is a true value and the server_software attribute is set.

예외 처리를 사용자 정의하기 위한 메서드와 어트리뷰트:

log_exception(exc_info)

exc_info 튜플을 서버 로그에 기록합니다. exc_info는 (type, value, traceback) 튜플입니다. 기본 구현은 요청의 wsgi.errors 스트림에 트레이스백을 쓰고 플러시 합니다. 서브 클래스는 이 메서드를 재정의해서, 형식을 변경하거나 출력의 대상을 바꾸거나, 관리자에게 트레이스백을 메일로 보내거나, 적절한 것으로 생각되는 다른 액션을 수행할 수 있습니다.

traceback_limit

기본 log_exception() 메서드에 의해 출력되는 트레이스백에 포함하는 프레임의 최대 수. None이면, 모든 프레임이 포함됩니다.

error_output(environ, start_response)

이 메서드는 사용자를 위한 에러 페이지를 생성하는 WSGI 응용 프로그램입니다. 헤더가 클라이언트에 전송되기 전에 오류가 발생할 때만 호출됩니다.

This method can access the current error using sys.exception(), and should pass that information to start_response when calling it (as described in the “Error Handling” section of PEP 3333 [https://peps.python.org/pep-3333/]).

기본 구현은 error_status, error_headers 및 error_body 어트리뷰트를 사용하여 출력 페이지를 생성합니다. 서브 클래스는 이것을 재정의하여, 더욱 동적인 에러 출력을 생성할 수 있습니다.

그러나, 보안 관점에서 오래된 사용자에게는 진단을 내보내지 않는 것이 좋습니다; 이상적으로, 진단 출력을 활성화하기 위해서는 특별한 것을 해야 합니다. 이것이 기본 구현이 아무것도 포함하지 않는 이유입니다.

error_status

에러 응답에 사용되는 HTTP 상태. PEP 3333 [https://peps.python.org/pep-3333/]에 정의된 상태 문자열이어야 합니다; 기본값은 500 코드와 메시지입니다.

error_headers

에러 응답에 사용되는 HTTP 헤더. 이것은 PEP 3333 [https://peps.python.org/pep-3333/]에서 설명하는 WSGI 응답 헤더 ((name, value) 튜플)의 리스트여야 합니다. 기본 리스트는 단지 콘텐츠 형식을 text/plain으로 설정합니다.

error_body

에러 응답 바디. 이것은 HTTP 응답 바디 바이트열이어야 합니다. 기본적으로 “A server error occurred. Please contact the administrator.” 라는 단순 텍스트입니다.

PEP 3333 [https://peps.python.org/pep-3333/]의 “선택적 플랫폼 특정 파일 처리” 기능을 위한 메서드와 어트리뷰트:

wsgi_file_wrapper

A wsgi.file_wrapper factory, compatible with wsgiref.types.FileWrapper, or None. The default value of this attribute is the wsgiref.util.FileWrapper class.

sendfile()

플랫폼 특정 파일 전송을 구현하기 위해 재정의합니다. 이 메서드는 응용 프로그램의 반환 값이 wsgi_file_wrapper 어트리뷰트로 지정된 클래스의 인스턴스일 때만 호출됩니다. 파일을 성공적으로 전송할 수 있었으면 참값을 반환해야 합니다. 그러면 기본 전송 코드가 실행되지 않습니다. 이 메서드의 기본 구현은 단지 거짓 값을 반환합니다.

기타 메서드와 어트리뷰트:

origin_server

특별한 Status: 헤더를 통해 HTTP 상태를 원하는 CGI와 같은 게이트웨이 프로토콜을 통하는 것이 아니라, 처리기의 _write()와 _flush()가 클라이언트와 직접 통신하는 데 사용되는 경우 이 어트리뷰트를 참으로 설정해야 합니다.

BaseHandler에서는 이 어트리뷰트의 기본값이 참이지만, BaseCGIHandler와 CGIHandler에서는 거짓입니다.

http_version

origin_server가 참이면, 이 문자열 어트리뷰트를 사용하여 클라이언트로 보내는 응답 집합의 HTTP 버전을 설정합니다. 기본값은 "1.0"입니다.

wsgiref.handlers.read_environ()

CGI 변수를 os.environ에서 PEP 3333 [https://peps.python.org/pep-3333/] “유니코드에 들어있는 바이트열” 문자열로 변환하여, 새 딕셔너리를 반환합니다. 이 함수는 os.environ을 직접 사용하는 대신 CGIHandler와 IISCGIHandler에서 사용됩니다. os.environ은 파이썬 3을 사용하는 모든 플랫폼과 웹 서버에서 WSGI를 준수한다는 보장이 없습니다 – 구체적으로, OS의 실제 환경이 유니코드인 곳(가령 윈도우)이나 환경은 바이트열이지만 파이썬이 디코딩하기 위해 사용하는 시스템 인코딩이 ISO-8859-1 이외의 것인 곳(예를 들어 UTF-8을 사용하는 유닉스 시스템).

여러분 자신의 CGI 기반 처리기를 구현한다면, os.environ에서 직접 값을 복사하는 대신 이 루틴을 사용하는 것이 좋습니다.

Added in version 3.2.

wsgiref.types – WSGI types for static type checking

This module provides various types for static type checking as described in PEP 3333 [https://peps.python.org/pep-3333/].

Added in version 3.11.

class wsgiref.types.StartResponse

A typing.Protocol describing start_response() [https://peps.python.org/pep-3333/#the-start-response-callable] callables (PEP 3333 [https://peps.python.org/pep-3333/]).

wsgiref.types.WSGIEnvironment

A type alias describing a WSGI environment dictionary.

wsgiref.types.WSGIApplication

A type alias describing a WSGI application callable.

class wsgiref.types.InputStream

A typing.Protocol describing a WSGI Input Stream [https://peps.python.org/pep-3333/#input-and-error-streams].

class wsgiref.types.ErrorStream

A typing.Protocol describing a WSGI Error Stream [https://peps.python.org/pep-3333/#input-and-error-streams].

class wsgiref.types.FileWrapper

A typing.Protocol describing a file wrapper [https://peps.python.org/pep-3333/#optional-platform-specific-file-handling]. See wsgiref.util.FileWrapper for a concrete implementation of this protocol.

예제

이것은 “Hello World” WSGI 응용 프로그램입니다:

"""
Every WSGI application must have an application object - a callable
object that accepts two arguments. For that purpose, we're going to
use a function (note that you're not limited to a function, you can
use a class for example). The first argument passed to the function
is a dictionary containing CGI-style environment variables and the
second variable is the callable object.
"""
from wsgiref.simple_server import make_server

def hello_world_app(environ, start_response):
    status = "200 OK"  # HTTP Status
    headers = [("Content-type", "text/plain; charset=utf-8")]  # HTTP Headers
    start_response(status, headers)

    # The returned object is going to be printed
    return [b"Hello World"]

with make_server("", 8000, hello_world_app) as httpd:
    print("Serving on port 8000...")

    # Serve until process is killed
    httpd.serve_forever()

Example of a WSGI application serving the current directory, accept optional directory and port number (default: 8000) on the command line:

"""
Small wsgiref based web server. Takes a path to serve from and an
optional port number (defaults to 8000), then tries to serve files.
MIME types are guessed from the file names, 404 errors are raised
if the file is not found.
"""
import mimetypes
import os
import sys
from wsgiref import simple_server, util

def app(environ, respond):
    # Get the file name and MIME type
    fn = os.path.join(path, environ["PATH_INFO"][1:])
    if "." not in fn.split(os.path.sep)[-1]:
        fn = os.path.join(fn, "index.html")
    mime_type = mimetypes.guess_file_type(fn)[0]

    # Return 200 OK if file exists, otherwise 404 Not Found
    if os.path.exists(fn):
        respond("200 OK", [("Content-Type", mime_type)])
        return util.FileWrapper(open(fn, "rb"))
    else:
        respond("404 Not Found", [("Content-Type", "text/plain")])
        return [b"not found"]

if __name__ == "__main__":
    # Get the path and port from command-line arguments
    path = sys.argv[1] if len(sys.argv) > 1 else os.getcwd()
    port = int(sys.argv[2]) if len(sys.argv) > 2 else 8000

    # Make and start the server until control-c
    httpd = simple_server.make_server("", port, app)
    print(f"Serving {path} on port {port}, control-C to stop")
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        print("Shutting down.")
        httpd.server_close()

urllib — URL handling modules

소스 코드: Lib/urllib/ [https://github.com/python/cpython/tree/main/Lib/urllib/]

urllib는 URL 작업을 위한 여러 모듈을 모은 패키지입니다.:

URL을 열고 읽기 위한 urllib.request

urllib.request에 의해 발생하는 예외를 포함하는 urllib.error

URL 구문 분석을 위한 urllib.parse

robots.txt 파일을 구문 분석하기 위한 urllib.robotparser

urllib.request — Extensible library for opening URLs

소스 코드: Lib/urllib/request.py [https://github.com/python/cpython/tree/main/Lib/urllib/request.py]

urllib.request 모듈은 복잡한 세계에서 URL(대부분 HTTP)을 여는 데 도움이 되는 함수와 클래스를 정의합니다 — 기본(basic)과 다이제스트 인증, 리디렉션, 쿠키 등.

더 보기

더 고수준 HTTP 클라이언트 인터페이스로 Requests 패키지 [https://requests.readthedocs.io/en/master/]를 권장합니다.

경고

On macOS it is unsafe to use this module in programs using os.fork() because the getproxies() implementation for macOS uses a higher-level system API. Set the environment variable no_proxy to * to avoid this problem (e.g. os.environ["no_proxy"] = "*").

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

urllib.request 모듈은 다음 함수를 정의합니다:

urllib.request.urlopen(url, data=None, [timeout, ]*, context=None)

Open url, which can be either a string containing a valid, properly encoded URL, or a Request object.

data는 서버로 전송할 추가 데이터를 지정하는 객체이거나, 그러한 데이터가 필요하지 않으면 None이어야 합니다. 자세한 내용은 Request를 참조하십시오.

urllib.request 모듈은 HTTP/1.1을 사용하고 HTTP 요청에 Connection:close 헤더를 포함합니다.

선택적 timeout 매개 변수는 연결 시도와 같은 연산을 블로킹하기 위한 시간제한을 초 단위로 지정합니다 (지정하지 않으면 전역 기본 시간제한 설정이 사용됩니다). 이것은 실제로는 HTTP, HTTPS 및 FTP 연결에서만 작동합니다.

context가 지정되면, 다양한 SSL 옵션을 기술하는 ssl.SSLContext 인스턴스이어야 합니다. 자세한 내용은 HTTPSConnection을 참조하십시오.

이 함수는 항상 컨텍스트 관리자로 작동할 수 있고 url, headers 및 status 프로퍼티를 가진 객체를 반환합니다. 이러한 프로퍼티에 대한 자세한 내용은 urllib.response.addinfourl을 참조하십시오.

HTTP 및 HTTPS URL의 경우, 이 함수는 약간 수정된 http.client.HTTPResponse 객체를 반환합니다. 위의 세 가지 새로운 메서드 외에도, msg 어트리뷰트에는 HTTPResponse 설명서에 지정된 대로 응답 헤더 대신 reason 어트리뷰트와 — 서버가 반환한 이유 문구 — 같은 정보가 포함됩니다.

For FTP, file, and data URLs, this function returns a urllib.response.addinfourl object.

프로토콜 에러 시 URLError를 발생시킵니다.

아무런 처리기도 요청을 처리하지 않으면 None이 반환될 수 있습니다 (기본 설치된 전역 OpenerDirector는 UnknownHandler를 사용하여 이러한 상황이 발생하지 않도록 합니다).

In addition, if proxy settings are detected (for example, when a *_proxy environment variable like http_proxy is set), ProxyHandler is default installed and makes sure the requests are handled through the proxy.

파이썬 2.6 및 이전 버전의 레거시 urllib.urlopen 함수는 중단되었습니다; urllib.request.urlopen()는 이전 urllib2.urlopen에 해당합니다. 딕셔너리 매개 변수를 urllib.urlopen에 전달하여 수행되었던 프락시 처리는 ProxyHandler 객체를 사용하여 얻을 수 있습니다.

기본 오프너는 요청 객체에서 취한 인자 fullurl, data, headers, method로 감사 이벤트 urllib.Request를 발생시킵니다.

버전 3.2에서 변경: cafile과 capath가 추가되었습니다.

HTTPS virtual hosts are now supported if possible (that is, if ssl.HAS_SNI is true).

data는 이터러블 객체일 수 있습니다.

버전 3.3에서 변경: cadefault가 추가되었습니다.

버전 3.4.3에서 변경: context가 추가되었습니다.

버전 3.10에서 변경: HTTPS connection now send an ALPN extension with protocol indicator http/1.1 when no context is given. Custom context should set ALPN protocols with set_alpn_protocols().

버전 3.13에서 변경: Remove cafile, capath and cadefault parameters: use the context parameter instead.

urllib.request.install_opener(opener)

OpenerDirector 인스턴스를 기본 전역 오프너로 설치합니다. 오프너 설치는 urlopen이 해당 오프너를 사용하도록 하려는 경우에만 필요합니다; 그렇지 않으면 단순히 urlopen() 대신 OpenerDirector.open()을 호출하십시오. 코드는 실제 OpenerDirector를 확인하지 않으며, 적절한 인터페이스를 가진 클래스면 모두 작동합니다.

urllib.request.build_opener([handler, ...])

주어진 순서대로 처리기를 연결하는 OpenerDirector 인스턴스를 반환합니다. handler는 BaseHandler의 인스턴스이거나 BaseHandler의 서브 클래스(이 경우 매개 변수 없이 생성자를 호출할 수 있어야 합니다)일 수 있습니다. 다음과 같은 클래스들의 인스턴스는 handler에 그들, 그들의 인스턴스 또는 그들의 서브 클래스가 포함되지 않는 한 handler 앞에 있습니다: ProxyHandler (프락시 설정이 감지되는 경우), UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor.

파이썬 설치에 SSL 지원이 있으면 (즉, ssl 모듈을 임포트 할 수 있으면) HTTPSHandler도 추가됩니다.

BaseHandler 서브 클래스는 또한 handler_order 어트리뷰트를 변경하여 처리기 리스트에서 자신의 위치를 수정할 수 있습니다.

urllib.request.pathname2url(path)

Convert the given local path to a file: URL. This function uses quote() function to encode the path. For historical reasons, the return value omits the file: scheme prefix. This example shows the function being used on Windows:

>>> from urllib.request import pathname2url
>>> path = 'C:\\Program Files'
>>> 'file:' + pathname2url(path)
'file:///C:/Program%20Files'

버전 3.14에서 변경: Paths beginning with a slash are converted to URLs with authority sections. For example, the path /etc/hosts is converted to the URL ///etc/hosts.

버전 3.14에서 변경: Windows drive letters are no longer converted to uppercase, and : characters not following a drive letter no longer cause an OSError exception to be raised on Windows.

urllib.request.url2pathname(url)

Convert the given file: URL to a local path. This function uses unquote() to decode the URL. For historical reasons, the given value must omit the file: scheme prefix. This example shows the function being used on Windows:

>>> from urllib.request import url2pathname
>>> url = 'file:///C:/Program%20Files'
>>> url2pathname(url.removeprefix('file:'))
'C:\\Program Files'

버전 3.14에서 변경: Windows drive letters are no longer converted to uppercase.

urllib.request.getproxies()

This helper function returns a dictionary of scheme to proxy server URL mappings. It scans the environment for variables named <scheme>_proxy, in a case insensitive approach, for all operating systems first, and when it cannot find it, looks for proxy information from System Configuration for macOS and Windows Systems Registry for Windows. If both lowercase and uppercase environment variables exist (and disagree), lowercase is preferred.

참고

일반적으로 스크립트가 CGI 환경에서 실행 중임을 나타내는 환경 변수 REQUEST_METHOD가 설정되면, 환경 변수 HTTP_PROXY(대문자 _PROXY)는 무시됩니다. 이 변수는 “Proxy:” HTTP 헤더를 사용하여 클라이언트가 주입할 수 있기 때문입니다. CGI 환경에서 HTTP 프락시를 사용해야 하면, ProxyHandler를 명시적으로 사용하거나 변수 이름이 소문자(또는 적어도 _proxy 접미사)가 되도록 하십시오.

다음과 같은 클래스가 제공됩니다:

class urllib.request.Request(url, data=None, headers={}, origin_req_host=None, unverifiable=False, method=None)

이 클래스는 URL 요청의 추상화입니다.

url should be a string containing a valid, properly encoded URL.

data는 서버로 전송할 추가 데이터를 지정하는 객체이거나, 그러한 데이터가 필요하지 않으면 None이어야 합니다. 현재 HTTP 요청은 data를 사용하는 유일한 요청입니다. 지원되는 객체 형에는 바이트열, 파일류 객체 및 바이트열류 객체의 이터러블이 포함됩니다. Content-Length와 Transfer-Encoding 헤더 필드가 모두 제공되지 않으면, HTTPHandler는 data의 형에 따라 이러한 헤더를 설정합니다. Content-Length는 바이트열 객체를 보내는 데 사용되는 반면, RFC 7230 [https://datatracker.ietf.org/doc/html/rfc7230.html], 섹션 3.3.1에 지정된 Transfer-Encoding: chunked는 파일과 다른 이터러블을 보내는 데 사용됩니다.

HTTP POST 요청 메서드의 경우, data는 표준 application/x-www-form-urlencoded 형식의 버퍼여야 합니다. urllib.parse.urlencode() 함수는 매핑이나 2-튜플의 시퀀스를 취하고 이 형식의 ASCII 문자열을 반환합니다. data 매개 변수로 사용되기 전에 바이트열로 인코딩되어야 합니다.

headers should be a dictionary, and will be treated as if add_header() was called with each key and value as arguments. This is often used to “spoof” the User-Agent header value, which is used by a browser to identify itself – some HTTP servers only allow requests coming from common browsers as opposed to scripts. For example, Mozilla Firefox may identify itself as "Mozilla/5.0 (X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11", while urllib’s default user agent string is "Python-urllib/2.6" (on Python 2.6). All header keys are sent in camel case.

An appropriate Content-Type header should be included if the data argument is present. If this header has not been provided and data is not None, Content-Type: application/x-www-form-urlencoded will be added as a default.

다음 두 인자는 제삼자 HTTP 쿠키를 올바르게 처리하는 데에만 관심이 있습니다:

origin_req_host는 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]에 의해 정의된 대로 오리진 트랜잭션의 요청 호스트여야 합니다. 기본값은 http.cookiejar.request_host(self)입니다. 이것은 사용자가 시작한 원래 요청의 호스트 이름이나 IP 주소입니다. 예를 들어, HTML 문서의 이미지에 대한 요청이면, 이미지가 포함된 페이지에 대한 요청의 요청 호스트여야 합니다.

unverifiable은 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]에서 정의한 대로 요청을 확인할 수 없는지를 표시해야 합니다. 기본값은 False입니다. 확인할 수 없는 요청은 사용자에게 URL에 대한 승인 옵션이 없는 요청입니다. 예를 들어, HTML 문서의 이미지에 대한 요청이고, 사용자에게 이미지의 자동 가져오기를 승인할 수 있는 옵션이 없으면, 이것은 참이어야 합니다.

method should be a string that indicates the HTTP request method that will be used (e.g. 'HEAD'). If provided, its value is stored in the method attribute and is used by get_method(). The default is 'GET' if data is None or 'POST' otherwise. Subclasses may indicate a different default method by setting the method attribute in the class itself.

참고

data 객체가 콘텐츠를 두 번 이상 (예를 들어 콘텐츠를 한 번만 생성 할 수 있는 파일이나 이터러블) 전달할 수 없고 요청이 HTTP 리디렉션이나 인증을 위해 재시도되는 경우, 요청이 예상대로 작동하지 않습니다. data는 헤더 바로 다음에 HTTP 서버로 전송됩니다. 라이브러리에서 100-continue 예상(expectation)을 지원하지 않습니다.

버전 3.3에서 변경: Request.method 인자가 Request 클래스에 추가됩니다.

버전 3.4에서 변경: 클래스 수준에서 기본 Request.method를 지정할 수 있습니다.

버전 3.6에서 변경: Content-Length가 제공되지 않고 data가 None이나 바이트열 객체가 아닐 때 에러를 발생시키지 앖습니다. 대신 청크 전송 인코딩(chunked transfer encoding)으로 폴백 합니다.

class urllib.request.OpenerDirector

OpenerDirector 클래스는 서로 연결된 BaseHandler들을 통해 URL을 엽니다. 처리기 연결과 에러 복구를 관리합니다.

class urllib.request.BaseHandler

이것은 등록된 모든 처리기의 베이스 클래스이며 — 간단한 등록 메커니즘만 처리합니다.

class urllib.request.HTTPDefaultErrorHandler

HTTP 에러 응답에 대한 기본 처리기를 정의하는 클래스; 모든 응답은 HTTPError 예외로 바뀝니다.

class urllib.request.HTTPRedirectHandler

리디렉션을 처리하는 클래스.

class urllib.request.HTTPCookieProcessor(cookiejar=None)

HTTP 쿠키를 처리하는 클래스.

class urllib.request.ProxyHandler(proxies=None)

Cause requests to go through a proxy. If proxies is given, it must be a dictionary mapping protocol names to URLs of proxies. The default is to read the list of proxies from the environment variables <protocol>_proxy. If no proxy environment variables are set, then in a Windows environment proxy settings are obtained from the registry’s Internet Settings section, and in a macOS environment proxy information is retrieved from the System Configuration Framework.

자동 감지 프락시를 비활성화하려면 빈 딕셔너리를 전달하십시오.

no_proxy 환경 변수를 사용하여 프락시를 통해 도달해서는 안 되는 호스트를 지정할 수 있습니다; 설정되면, 쉼표로 구분된 호스트 이름 접미사의 목록이어야 하며, 선택적으로 :port가 추가됩니다, 예를 들어 cern.ch,ncsa.uiuc.edu,some.host:8080.

참고

변수 REQUEST_METHOD가 설정되면 HTTP_PROXY는 무시됩니다; getproxies()의 설명서를 참조하십시오.

class urllib.request.HTTPPasswordMgr

(realm, uri) -> (user, password) 매핑 데이터베이스를 유지합니다.

class urllib.request.HTTPPasswordMgrWithDefaultRealm

(realm, uri) -> (user, password) 매핑 데이터베이스를 유지합니다. None realm은 포괄(catch-all) 영역으로 간주하며 다른 영역에 맞지 않으면 검색됩니다.

class urllib.request.HTTPPasswordMgrWithPriorAuth

uri -> is_authenticated 매핑 데이터베이스도 포함하는 HTTPPasswordMgrWithDefaultRealm의 변형. BasicAuth 처리기에서 401 응답을 먼저 기다리는 대신 인증 자격 증명을 언제 보낼 것인지 결정하는 데 사용할 수 있습니다.

Added in version 3.5.

class urllib.request.AbstractBasicAuthHandler(password_mgr=None)

원격 호스트와 프락시 모두에서 HTTP 인증을 돕는 믹스인 클래스입니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오. passwd_mgr이 is_authenticated와 update_authenticated 메서드도 제공하면 (HTTPPasswordMgrWithPriorAuth 객체를 참조하십시오), 처리기는 지정된 URI에 대해 is_authenticated 결과를 사용하여 요청과 함께 인증 자격 증명을 보낼지를 판별합니다. is_authenticated가 URI에 대해 True를 반환하면, 자격 증명이 전송됩니다. is_authenticated가 False이면, 자격 증명이 전송되지 않으며, 그런 다음 401 응답이 수신되면 요청이 인증 자격 증명과 함께 다시 전송됩니다. 인증이 성공하면, 이 URI에 대해 is_authenticated를 True로 설정하기 위해 update_authenticated가 호출되어서, 이 URI나 모든 슈퍼 URI에 대한 후속 요청에 인증 자격 증명이 자동으로 포함됩니다.

Added in version 3.5: is_authenticated 지원이 추가되었습니다.

class urllib.request.HTTPBasicAuthHandler(password_mgr=None)

원격 호스트와의 인증을 처리합니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오. 잘못된 인증 스킴(Authentication scheme)을 제시하면 HTTPBasicAuthHandler 가 ValueError를 발생시킵니다.

class urllib.request.ProxyBasicAuthHandler(password_mgr=None)

프락시와의 인증을 처리합니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오.

class urllib.request.AbstractDigestAuthHandler(password_mgr=None)

원격 호스트와 프락시 모두에서 HTTP 인증을 돕는 믹스인 클래스입니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오.

class urllib.request.HTTPDigestAuthHandler(password_mgr=None)

원격 호스트와의 인증을 처리합니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오. 다이제스트 인증 처리기와 기본 인증 처리기가 모두 추가되면, 다이제스트 인증이 항상 먼저 시도됩니다. 다이제스트 인증이 다시 40x 응답을 반환하면, 기본 인증 처리기로 보내 처리됩니다. 이 처리기 메서드는 Digest나 Basic 이외의 인증 스킴(authentication scheme)이 제공될 때 ValueError를 발생시킵니다.

버전 3.3에서 변경: 지원되지 않는 인증 스킴에 대해 ValueError를 발생시킵니다.

class urllib.request.ProxyDigestAuthHandler(password_mgr=None)

프락시와의 인증을 처리합니다. password_mgr이 주어지면 HTTPPasswordMgr 과 호환되는 것이어야 합니다; 지원해야 하는 인터페이스에 대한 정보는 섹션 HTTPPasswordMgr 객체를 참조하십시오.

class urllib.request.HTTPHandler

HTTP URL 열기를 처리하는 클래스.

class urllib.request.HTTPSHandler(debuglevel=0, context=None, check_hostname=None)

HTTPS URL 열기를 처리하는 클래스. context와 check_hostname은 http.client.HTTPSConnection과 같은 의미입니다.

버전 3.2에서 변경: context와 check_hostname이 추가되었습니다.

class urllib.request.FileHandler

로컬 파일을 엽니다.

class urllib.request.DataHandler

데이터 URL을 엽니다.

Added in version 3.4.

class urllib.request.FTPHandler

FTP URL을 엽니다.

class urllib.request.CacheFTPHandler

지연 시간을 최소화하기 위해 열린 FTP 연결의 캐시를 유지하면서, FTP URL을 엽니다.

class urllib.request.UnknownHandler

알 수 없는 URL을 처리하기 위한 포괄적인(catch-all) 클래스.

class urllib.request.HTTPErrorProcessor

HTTP 에러 응답을 처리합니다.

Request 객체

다음 메서드는 Request의 공용 인터페이스를 설명하므로, 서브 클래스에서 모두 재정의될 수 있습니다. 또한 클라이언트가 구문 분석된 요청을 검사하는 데 사용할 수 있는 몇 가지 공용 어트리뷰트를 정의합니다.

Request.full_url

생성자에 전달된 원래 URL.

버전 3.4에서 변경.

Request.full_url은 setter, getter 및 deleter가 있는 프로퍼티입니다. full_url을 읽으면 프래그먼트가 있는 원래 요청 URL을 반환합니다 (있다면).

Request.type

URI 스킴.

Request.host

URI 주체(authority), 일반적으로 호스트이지만 콜론으로 구분된 포트를 포함할 수도 있습니다.

Request.origin_req_host

포트가 없는, 요청의 원래 호스트.

Request.selector

URI 경로. Request가 프락시를 사용하면, selector는 프락시로 전달되는 전체 URL이 됩니다.

Request.data

요청의 엔티티 바디, 또는 지정되지 않으면 None.

버전 3.4에서 변경: Request.data의 값을 변경하면 이제 “Content-Length” 헤더가 이전에 설정되거나 계산되었다면 삭제됩니다.

Request.unverifiable

불리언, RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]에서 정의한 대로 요청을 확인할 수 없는지를 나타냅니다.

Request.method

사용할 HTTP 요청 메서드. 기본적으로 값은 None입니다. 이는 get_method()가 사용될 메서드의 일반적인 계산을 수행함을 뜻합니다. Request 서브 클래스의 클래스 수준에서 값을 설정해서 기본값을 제공하거나, method 인자를 통해 Request 생성자에 값을 전달하여 값을 설정할 수 있습니다 (그래서 get_method()의 기본 계산을 무시합니다).

Added in version 3.3.

버전 3.4에서 변경: 서브 클래스에서 이제 기본값을 설정할 수 있습니다; 이전에는 생성자 인자를 통해서만 설정할 수 있었습니다.

Request.get_method()

HTTP 요청 메서드를 나타내는 문자열을 반환합니다. Request.method가 None이 아니면, 그 값을 반환하고, 그렇지 않으면 Request.data가 None이면 'GET'을 반환하거나 그렇지 않으면 'POST'를 반환합니다. 이것은 HTTP 요청에만 의미가 있습니다.

버전 3.3에서 변경: get_method는 이제 Request.method의 값을 조사합니다.

Request.add_header(key, val)

Add another header to the request. Headers are currently ignored by all handlers except HTTP handlers, where they are added to the list of headers sent to the server. Note that there cannot be more than one header with the same name, and later calls will overwrite previous calls in case the key collides. Currently, this is no loss of HTTP functionality, since all headers which have meaning when used more than once have a (header-specific) way of gaining the same functionality using only one header. Note that headers added using this method are also added to redirected requests.

Request.add_unredirected_header(key, header)

리디렉션 된 요청에 추가되지 않을 헤더를 추가합니다.

Request.has_header(header)

인스턴스에 명명된 헤더가 있는지를 반환합니다 (일반과 리디렉션되지 않는 것을 모두 확인합니다).

Request.remove_header(header)

요청 인스턴스에서 명명된 헤더를 제거합니다 (일반과 리디렉션되지 않은 헤더 모두).

Added in version 3.4.

Request.get_full_url()

생성자에 제공된 URL을 반환합니다.

버전 3.4에서 변경.

Request.full_url을 반환합니다

Request.set_proxy(host, type)

프락시 서버에 연결하여 요청을 준비합니다. host와 type은 인스턴스의 것을 대체하고, 인스턴스의 selector는 생성자에 제공된 원래 URL이 됩니다.

Request.get_header(header_name, default=None)

지정된 헤더의 값을 반환합니다. 헤더가 없으면, default 값을 반환합니다.

Request.header_items()

요청 헤더의 튜플 (header_name, header_value) 리스트를 반환합니다.

버전 3.4에서 변경: 3.3부터 폐지된 add_data, has_data, get_data, get_type, get_host, get_selector, get_origin_req_host 및 is_unverifiable 요청 메서드가 제거되었습니다.

OpenerDirector 객체

OpenerDirector 인스턴스에는 다음과 같은 메서드가 있습니다:

OpenerDirector.add_handler(handler)

handler는 BaseHandler의 인스턴스여야 합니다. 다음 메서드가 검색되어, 가능한 체인에 추가됩니다 (HTTP 에러는 특별한 경우임에 유의하십시오). 다음에서 protocol은 처리할 실제 프로토콜로 바꿔야 합니다, 예를 들어 http_response()는 HTTP 프로토콜 응답 처리기입니다. 또한 type은 실제 HTTP 코드로 대체해야 합니다, 예를 들어 http_error_404()는 HTTP 404 에러를 처리합니다.

<protocol>_open() — signal that the handler knows how to open protocol URLs.

자세한 정보는 BaseHandler.<protocol>_open()을 참조하십시오.

http_error_<type>() — signal that the handler knows how to handle HTTP errors with HTTP error code type.

자세한 정보는 BaseHandler.http_error_<nnn>()을 참조하십시오.

<protocol>_error() — signal that the handler knows how to handle errors from (non-http) protocol.

<protocol>_request() — signal that the handler knows how to pre-process protocol requests.

자세한 정보는 BaseHandler.<protocol>_request()를 참조하십시오.

<protocol>_response() — signal that the handler knows how to post-process protocol responses.

자세한 정보는 BaseHandler.<protocol>_response()를 참조하십시오.

OpenerDirector.open(url, data=None[, timeout])

Open the given url (which can be a request object or a string), optionally passing the given data. Arguments, return values and exceptions raised are the same as those of urlopen() (which simply calls the open() method on the currently installed global OpenerDirector). The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). The timeout feature actually works only for HTTP, HTTPS and FTP connections.

OpenerDirector.error(proto, *args)

Handle an error of the given protocol. This will call the registered error handlers for the given protocol with the given arguments (which are protocol specific). The HTTP protocol is a special case which uses the HTTP response code to determine the specific error handler; refer to the http_error_<type>() methods of the handler classes.

반환 값과 발생하는 예외는 urlopen()과 같습니다.

OpenerDirector 객체는 다음 3단계로 URL을 엽니다:

각 단계에서 이러한 메서드가 호출되는 순서는 처리기 인스턴스를 정렬하여 결정됩니다.

Every handler with a method named like <protocol>_request() has that method called to pre-process the request.

Handlers with a method named like <protocol>_open() are called to handle the request. This stage ends when a handler either returns a non-None value (ie. a response), or raises an exception (usually URLError). Exceptions are allowed to propagate.

In fact, the above algorithm is first tried for methods named default_open(). If all such methods return None, the algorithm is repeated for methods named like <protocol>_open(). If all such methods return None, the algorithm is repeated for methods named unknown_open().

이러한 메서드의 구현은 부모 OpenerDirector 인스턴스의 open()과 error() 메서드의 호출을 수반할 수 있음에 유의하십시오.

Every handler with a method named like <protocol>_response() has that method called to post-process the response.

BaseHandler 객체

BaseHandler 객체는 직접적으로 유용한 몇 가지 메서드와 파생 클래스에서 사용하기 위한 다른 메서드를 제공합니다. 다음은 직접 사용하기 위한 것입니다:

BaseHandler.add_parent(director)

director를 부모로 추가합니다.

BaseHandler.close()

모든 부모를 제거합니다.

다음 어트리뷰트와 메서드는 BaseHandler에서 파생된 클래스에서만 사용해야 합니다.

참고

The convention has been adopted that subclasses defining <protocol>_request() or <protocol>_response() methods are named *Processor; all others are named *Handler.

BaseHandler.parent

다른 프로토콜을 사용하여 열거나 에러를 처리하는 데 사용할 수 있는 유효한 OpenerDirector.

BaseHandler.default_open(req)

이 메서드는 BaseHandler에 정의되지 않았지만, 서브 클래스가 모든 URL을 포착하려면 이를 정의해야 합니다.

This method, if implemented, will be called by the parent OpenerDirector. It should return a file-like object as described in the return value of the open() method of OpenerDirector, or None. It should raise URLError, unless a truly exceptional thing happens (for example, MemoryError should not be mapped to URLError).

이 메서드는 프로토콜별 open 메서드보다 먼저 호출됩니다.

BaseHandler.<protocol>_open(req)

이 메서드는 BaseHandler 에 정의되지 않았지만, 서브 클래스가 주어진 프로토콜로 URL을 처리하려면 이를 정의해야 합니다.

This method, if defined, will be called by the parent OpenerDirector. Return values should be the same as for default_open().

BaseHandler.unknown_open(req)

이 메서드는 BaseHandler 에 정의되지 않았지만, 서브 클래스는 등록된 특정 처리기가 없는 모든 URL을 잡아서 열려면 이를 정의해야 합니다.

구현되면, 이 메서드는 parent OpenerDirector에 의해 호출됩니다. 반환 값은 default_open()과 같아야 합니다.

BaseHandler.http_error_default(req, fp, code, msg, hdrs)

이 메서드는 BaseHandler 에 정의되지 않았지만, 서브 클래스는 달리 처리되지 않은 HTTP 에러에 대해 포괄적인 처리를 제공하려면 이를 재정의해야 합니다. 에러가 발생하는 OpenerDirector에 의해 자동으로 호출되며, 다른 상황에서는 일반적으로 호출되지 않아야 합니다.

req는 Request 객체, fp는 HTTP 에러 바디가 있는 파일류 객체, code는 에러의 3자리 코드, msg는 사용자가 볼 수 있는 코드 설명, hdrs는 에러의 헤더가 있는 매핑 객체가 됩니다.

반환 값과 발생하는 예외는 urlopen()의 것과 같아야 합니다.

BaseHandler.http_error_<nnn>(req, fp, code, msg, hdrs)

nnn은 3자리 HTTP 에러 코드여야 합니다. 이 메서드도 BaseHandler 에 정의되어 있지 않지만, 존재한다면 코드가 nnn 인 HTTP 에러가 발생할 때 서브 클래스의 인스턴스에 대해 호출됩니다.

특정 HTTP 에러를 처리하려면 서브 클래스가 이 메서드를 재정의해야 합니다.

Arguments, return values and exceptions raised should be the same as for http_error_default().

BaseHandler.<protocol>_request(req)

이 메서드는 BaseHandler 에 정의되지 않았지만, 서브 클래스는 주어진 프로토콜의 요청을 전처리하려면 이를 정의해야 합니다.

정의되면, 이 메서드는 부모 상위 OpenerDirector에 의해 호출됩니다. req는 Request 객체가 됩니다. 반환 값은 Request 객체여야 합니다.

BaseHandler.<protocol>_response(req, response)

이 메서드는 BaseHandler 에 정의되지 않았지만, 서브 클래스는 주어진 프로토콜의 응답을 후처리하려면 이를 정의해야 합니다.

정의되면, 이 메서드는 부모 OpenerDirector에 의해 호출됩니다. req는 Request 객체가 됩니다. response는 urlopen()의 반환 값과 같은 인터페이스를 구현하는 객체가 됩니다. 반환 값은 urlopen()의 반환 값과 같은 인터페이스를 구현해야 합니다.

HTTPRedirectHandler 객체

참고

일부 HTTP 리디렉션은 이 모듈의 클라이언트 코드로부터의 액션을 요구합니다. 이 경우, HTTPError가 발생합니다. 다양한 리디렉션 코드의 정확한 의미에 대한 자세한 내용은 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]을 참조하십시오.

An HTTPError exception raised as a security consideration if the HTTPRedirectHandler is presented with a redirected URL which is not an HTTP, HTTPS or FTP URL.

HTTPRedirectHandler.redirect_request(req, fp, code, msg, hdrs, newurl)

Return a Request or None in response to a redirect. This is called by the default implementations of the http_error_30*() methods when a redirection is received from the server. If a redirection should take place, return a new Request to allow http_error_30*() to perform the redirect to newurl. Otherwise, raise HTTPError if no other handler should try to handle this URL, or return None if you can’t but another handler might.

참고

이 메서드의 기본 구현은 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]을 엄격하게 따르지 않습니다. 즉, POST 요청에 대한 301과 302 응답은 사용자의 확인 없이 자동으로 리디렉션 되지 않아야 합니다. 실제로는, 브라우저들이 POST를 GET으로 변경하여 이러한 응답의 자동 리디렉션을 허용하며, 기본 구현은 이 동작을 재현합니다.

HTTPRedirectHandler.http_error_301(req, fp, code, msg, hdrs)

Location:이나 URI: URL로 리디렉션 합니다. 이 메서드는 HTTP ‘moved permanently(영구적으로 이전했음)’ 응답을 받을 때 부모 OpenerDirector에 의해 호출됩니다.

HTTPRedirectHandler.http_error_302(req, fp, code, msg, hdrs)

http_error_301()과 같지만, ‘found(발견됨)’ 응답에 대해 호출됩니다.

HTTPRedirectHandler.http_error_303(req, fp, code, msg, hdrs)

http_error_301()과 같지만, ‘see other(다른 곳을 보세요)’ 응답에 대해 호출됩니다.

HTTPRedirectHandler.http_error_307(req, fp, code, msg, hdrs)

The same as http_error_301(), but called for the ‘temporary redirect’ response. It does not allow changing the request method from POST to GET.

HTTPRedirectHandler.http_error_308(req, fp, code, msg, hdrs)

The same as http_error_301(), but called for the ‘permanent redirect’ response. It does not allow changing the request method from POST to GET.

Added in version 3.11.

HTTPCookieProcessor 객체

HTTPCookieProcessor 인스턴스에는 하나의 어트리뷰트가 있습니다:

HTTPCookieProcessor.cookiejar

쿠키가 저장되는 http.cookiejar.CookieJar.

ProxyHandler 객체

ProxyHandler.<protocol>_open(request)

The ProxyHandler will have a method <protocol>_open() for every protocol which has a proxy in the proxies dictionary given in the constructor. The method will modify requests to go through the proxy, by calling request.set_proxy(), and call the next handler in the chain to actually execute the protocol.

HTTPPasswordMgr 객체

이 메서드는 HTTPPasswordMgr 과 HTTPPasswordMgrWithDefaultRealm 객체에서 사용 가능합니다.

HTTPPasswordMgr.add_password(realm, uri, user, passwd)

uri는 단일 URI이거나 URI의 시퀀스일 수 있습니다. realm, user 및 passwd는 문자열이어야 합니다. 이는 realm과 지정된 URI 중 어느 하나의 슈퍼 URI에 대한 인증이 주어질 때 (user, passwd)가 인증 토큰으로 사용되도록 합니다.

HTTPPasswordMgr.find_user_password(realm, authuri)

주어진 realm과 URI에 대한 사용자/암호를 (있다면) 가져옵니다. 일치하는 사용자/암호가 없으면 이 메서드는 (None, None)을 반환합니다.

HTTPPasswordMgrWithDefaultRealm 객체의 경우, 주어진 realm에 일치하는 사용자/암호가 없으면 영역 None이 검색됩니다.

HTTPPasswordMgrWithPriorAuth 객체

이 암호 관리자는 HTTPPasswordMgrWithDefaultRealm를 확장하여 인증 자격 증명을 항상 보내야 하는 URI를 추적하는 것을 지원합니다.

HTTPPasswordMgrWithPriorAuth.add_password(realm, uri, user, passwd, is_authenticated=False)

realm, uri, user, passwd는 HTTPPasswordMgr.add_password()와 같습니다. is_authenticated는 주어진 URI나 URI 리스트에 대한 is_authenticated 플래그의 초깃값을 설정합니다. is_authenticated가 True로 지정되면, realm는 무시됩니다.

HTTPPasswordMgrWithPriorAuth.find_user_password(realm, authuri)

HTTPPasswordMgrWithDefaultRealm 객체와 같습니다

HTTPPasswordMgrWithPriorAuth.update_authenticated(self, uri, is_authenticated=False)

주어진 uri나 URI 리스트에 대해 is_authenticated 플래그를 갱신합니다.

HTTPPasswordMgrWithPriorAuth.is_authenticated(self, authuri)

주어진 URI에 대한 is_authenticated 플래그의 현재 상태를 반환합니다.

AbstractBasicAuthHandler 객체

AbstractBasicAuthHandler.http_error_auth_reqed(authreq, host, req, headers)

사용자/암호 쌍을 가져오고 요청을 다시 시도하여 인증 요청을 처리합니다. authreq는 영역(realm)에 대한 정보가 요청에 포함된 헤더의 이름이어야 하고, host는 인증할 URL과 경로를 지정하고, req는 (실패한) Request 객체여야 하며, headers는 에러 헤더여야 합니다.

host는 주체(예를 들어 "python.org")거나 주체 구성 요소를 포함하는 URL(예를 들어 "http://python.org/")입니다. 어느 경우이든, 주체는 userinfo 구성 요소를 포함하지 않아야 합니다 (따라서, "python.org"와 "python.org:80"은 좋지만, "joe:password@python.org"는 유효하지 않습니다).

HTTPBasicAuthHandler 객체

HTTPBasicAuthHandler.http_error_401(req, fp, code, msg, hdrs)

가능하다면 인증 정보로 요청을 재시도합니다.

ProxyBasicAuthHandler 객체

ProxyBasicAuthHandler.http_error_407(req, fp, code, msg, hdrs)

가능하다면 인증 정보로 요청을 재시도합니다.

AbstractDigestAuthHandler 객체

AbstractDigestAuthHandler.http_error_auth_reqed(authreq, host, req, headers)

authreq는 영역(realm)에 대한 정보가 요청에 포함된 헤더의 이름이어야 하고, host는 인증할 호스트여야 하고, req는 (실패한) Request 객체여야 하며, headers는 에러 헤더여야 합니다.

HTTPDigestAuthHandler 객체

HTTPDigestAuthHandler.http_error_401(req, fp, code, msg, hdrs)

가능하다면 인증 정보로 요청을 재시도합니다.

ProxyDigestAuthHandler 객체

ProxyDigestAuthHandler.http_error_407(req, fp, code, msg, hdrs)

가능하다면 인증 정보로 요청을 재시도합니다.

HTTPHandler 객체

HTTPHandler.http_open(req)

HTTP 요청을 보냅니다. req.has_data()에 따라, GET이나 POST일 수 있습니다.

HTTPSHandler 객체

HTTPSHandler.https_open(req)

HTTPS 요청을 보냅니다. req.has_data()에 따라, GET이나 POST일 수 있습니다.

FileHandler 객체

FileHandler.file_open(req)

호스트 이름이 없거나, 호스트 이름이 'localhost'인 경우 파일을 로컬에서 엽니다.

버전 3.2에서 변경: This method is applicable only for local hostnames. When a remote hostname is given, a URLError is raised.

DataHandler 객체

DataHandler.data_open(req)

Read a data URL. This kind of URL contains the content encoded in the URL itself. The data URL syntax is specified in RFC 2397 [https://datatracker.ietf.org/doc/html/rfc2397.html]. This implementation ignores white spaces in base64 encoded data URLs so the URL may be wrapped in whatever source file it comes from. But even though some browsers don’t mind about a missing padding at the end of a base64 encoded data URL, this implementation will raise a ValueError in that case.

FTPHandler 객체

FTPHandler.ftp_open(req)

req로 표시된 FTP 파일을 엽니다. 로그인은 항상 빈 사용자 이름과 암호로 수행됩니다.

CacheFTPHandler 객체

CacheFTPHandler 객체는 다음과 같은 추가 메서드가 있는 FTPHandler 객체입니다:

CacheFTPHandler.setTimeout(t)

연결 시간제한을 t 초로 설정합니다.

CacheFTPHandler.setMaxConns(m)

캐시 된 최대 연결 수를 m으로 설정합니다.

UnknownHandler 객체

UnknownHandler.unknown_open()

URLError 예외를 발생시킵니다.

HTTPErrorProcessor 객체

HTTPErrorProcessor.http_response(request, response)

HTTP 에러 응답을 처리합니다.

200 에러 코드의 경우, 응답 객체가 즉시 반환됩니다.

For non-200 error codes, this simply passes the job on to the http_error_<type>() handler methods, via OpenerDirector.error(). Eventually, HTTPDefaultErrorHandler will raise an HTTPError if no other handler handles the error.

HTTPErrorProcessor.https_response(request, response)

HTTPS 에러 응답을 처리합니다.

동작은 http_response()와 같습니다.

예

아래 예 외에도 urllib 패키지를 사용하여 인터넷 리소스를 가져오는 방법에는 더 많은 예가 나와 있습니다.

이 예제는 python.org 메인 페이지를 가져와서 첫 300바이트를 표시합니다.

>>> import urllib.request
>>> with urllib.request.urlopen('http://www.python.org/') as f:
...     print(f.read(300))
...
b'<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">\n\n\n<html
xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">\n\n<head>\n
<meta http-equiv="content-type" content="text/html; charset=utf-8" />\n
<title>Python Programming '

urlopen은 바이트열 객체를 반환함에 유의하십시오. 이는 urlopen이 HTTP 서버로부터 수신한 바이트 스트림의 인코딩을 자동으로 결정할 방법이 없기 때문입니다. 일반적으로, 프로그램은 일단 적절한 인코딩을 결정하거나 추측하면 반환된 바이트열 객체를 문자열로 디코딩합니다.

다음 W3C 문서 https://www.w3.org/International/O-charset는 (X)HTML이나 XML 문서가 인코딩 정보를 지정할 수 있는 다양한 방법을 나열합니다.

python.org 웹 사이트는 메타 태그에 지정된 대로 utf-8 인코딩을 사용하므로, 바이트열 객체를 디코딩할 때도 이를 사용합니다.

>>> with urllib.request.urlopen('http://www.python.org/') as f:
...     print(f.read(100).decode('utf-8'))
...
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtm

컨텍스트 관리자 방식을 사용하지 않고도 같은 결과를 얻을 수 있습니다.

>>> import urllib.request
>>> f = urllib.request.urlopen('http://www.python.org/')
>>> print(f.read(100).decode('utf-8'))
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtm

다음 예에서는, CGI의 표준 입력으로 데이터 스트림을 전송하고 반환되는 데이터를 읽습니다. 이 예제는 파이썬 설치가 SSL을 지원할 때만 작동함에 유의하십시오.

>>> import urllib.request
>>> req = urllib.request.Request(url='https://localhost/cgi-bin/test.cgi',
...                       data=b'This data is passed to stdin of the CGI')
>>> with urllib.request.urlopen(req) as f:
...     print(f.read().decode('utf-8'))
...
Got Data: "This data is passed to stdin of the CGI"

위 예제에서 사용한 샘플 CGI의 코드는 다음과 같습니다:

#!/usr/bin/env python
import sys
data = sys.stdin.read()
print('Content-type: text/plain\n\nGot Data: "%s"' % data)

다음은 Request를 사용하여 PUT 요청을 수행하는 예입니다:

import urllib.request
DATA = b'some data'
req = urllib.request.Request(url='http://localhost:8080', data=DATA, method='PUT')
with urllib.request.urlopen(req) as f:
    pass
print(f.status)
print(f.reason)

기본 HTTP 인증 사용:

import urllib.request
# Create an OpenerDirector with support for Basic HTTP Authentication...
auth_handler = urllib.request.HTTPBasicAuthHandler()
auth_handler.add_password(realm='PDQ Application',
                          uri='https://mahler:8092/site-updates.py',
                          user='klem',
                          passwd='kadidd!ehopper')
opener = urllib.request.build_opener(auth_handler)
# ...and install it globally so it can be used with urlopen.
urllib.request.install_opener(opener)
urllib.request.urlopen('http://www.example.com/login.html')

build_opener() provides many handlers by default, including a ProxyHandler. By default, ProxyHandler uses the environment variables named <scheme>_proxy, where <scheme> is the URL scheme involved. For example, the http_proxy environment variable is read to obtain the HTTP proxy’s URL.

This example replaces the default ProxyHandler with one that uses programmatically supplied proxy URLs, and adds proxy authorization support with ProxyBasicAuthHandler.

proxy_handler = urllib.request.ProxyHandler({'http': 'http://www.example.com:3128/'})
proxy_auth_handler = urllib.request.ProxyBasicAuthHandler()
proxy_auth_handler.add_password('realm', 'host', 'username', 'password')

opener = urllib.request.build_opener(proxy_handler, proxy_auth_handler)
# This time, rather than install the OpenerDirector, we use it directly:
opener.open('http://www.example.com/login.html')

HTTP 헤더 추가하기:

Request 생성자에 headers 인자를 사용하십시오, 또는:

import urllib.request
req = urllib.request.Request('http://www.example.com/')
req.add_header('Referer', 'http://www.python.org/')
# Customize the default User-Agent header value:
req.add_header('User-Agent', 'urllib-example/0.1 (Contact: . . .)')
r = urllib.request.urlopen(req)

OpenerDirector는 모든 Request에 User-Agent 헤더를 자동으로 추가합니다. 이것을 바꾸려면:

import urllib.request
opener = urllib.request.build_opener()
opener.addheaders = [('User-agent', 'Mozilla/5.0')]
opener.open('http://www.example.com/')

또한, Request가 urlopen()(또는 OpenerDirector.open())으로 전달될 때 몇 가지 표준 헤더(Content-Length, Content-Type 및 Host)가 추가됨을 기억하십시오.

다음은 GET 메서드를 사용하여 파라미터가 포함된 URL을 가져오는 예제 세션입니다:

>>> import urllib.request
>>> import urllib.parse
>>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> url = "http://www.musi-cal.com/cgi-bin/query?%s" % params
>>> with urllib.request.urlopen(url) as f:
...     print(f.read().decode('utf-8'))
...

다음 예제는 대신 POST 메서드를 사용합니다. urlencode의 파라미터 출력이 데이터로 urlopen에 보내기 전에 바이트열로 인코딩됨에 유의하십시오:

>>> import urllib.request
>>> import urllib.parse
>>> data = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> data = data.encode('ascii')
>>> with urllib.request.urlopen("http://requestb.in/xrbl82xr", data) as f:
...     print(f.read().decode('utf-8'))
...

다음 예제는 명시적으로 지정된 HTTP 프락시를 사용하여 환경 설정을 대체합니다:

>>> import urllib.request
>>> proxies = {'http': 'http://proxy.example.com:8080/'}
>>> opener = urllib.request.build_opener(urllib.request.ProxyHandler(proxies))
>>> with opener.open("http://www.python.org") as f:
...     f.read().decode('utf-8')
...

다음 예제는 프락시를 전혀 사용하지 않도록 환경 설정을 대체합니다:

>>> import urllib.request
>>> opener = urllib.request.build_opener(urllib.request.ProxyHandler({}}))
>>> with opener.open("http://www.python.org/") as f:
...     f.read().decode('utf-8')
...

레거시 인터페이스

다음 함수와 클래스는 파이썬 2 모듈 urllib(urllib2가 아니라)에서 이식됩니다. 나중에 언젠가 폐지될 수 있습니다.

urllib.request.urlretrieve(url, filename=None, reporthook=None, data=None)

Copy a network object denoted by a URL to a local file. If the URL points to a local file, the object will not be copied unless filename is supplied. Return a tuple (filename, headers) where filename is the local file name under which the object can be found, and headers is whatever the info() method of the object returned by urlopen() returned (for a remote object). Exceptions are the same as for urlopen().

있다면, 두 번째 인자는 복사할 파일 위치를 지정합니다 (없으면, 위치는 생성된 이름을 가진 임시 파일이 됩니다). 있다면, 세 번째 인자는 네트워크 연결이 이루어질 때 한 번 호출되고 그 이후에 각 블록을 읽을 때마다 한 번씩 호출되는 콜러블입니다. 콜러블에는 세 개의 인자가 전달됩니다; 지금까지 전송된 블록 수, 바이트 단위의 블록 크기 및 파일의 전체 크기. 세 번째 인자는 가져오기 요청에 대한 응답으로 파일 크기를 반환하지 않는 구형 FTP 서버에서 -1일 수 있습니다.

다음 예는 가장 일반적인 사용 시나리오를 보여줍니다:

>>> import urllib.request
>>> local_filename, headers = urllib.request.urlretrieve('http://python.org/')
>>> html = open(local_filename)
>>> html.close()

url이 http: 스킴 식별자를 사용하면, POST 요청을 지정하기 위해 선택적 data 인자가 제공될 수 있습니다 (일반적으로 요청형은 GET입니다). data 인자는 표준 application/x-www-form-urlencoded 형식의 바이트열 객체여야 합니다; urllib.parse.urlencode() 함수를 참조하십시오.

urlretrieve() will raise ContentTooShortError when it detects that the amount of data available was less than the expected amount (which is the size reported by a Content-Length header). This can occur, for example, when the download is interrupted.

Content-Length는 하한값으로 취급됩니다: 읽을 데이터가 더 있으면, urlretrieve는 더 많은 데이터를 읽지만, 사용 가능한 데이터가 부족하면 예외가 발생합니다.

You can still retrieve the downloaded data in this case, it is stored in the content attribute of the exception instance.

Content-Length 헤더가 제공되지 않으면, urlretrieve는 다운로드 한 데이터의 크기를 확인할 수 없고, 그냥 반환합니다. 이 경우 다운로드가 성공했다고 가정해야 합니다.

urllib.request.urlcleanup()

urlretrieve()에 대한 이전 호출로 남겨졌을 수 있는 임시 파일을 정리합니다.

urllib.request 제약 사항

현재, 다음과 같은 프로토콜만 지원됩니다: HTTP (버전 0.9와 1.0), FTP, 로컬 파일 및 데이터 URL.

버전 3.4에서 변경: 데이터 URL에 대한 지원이 추가되었습니다.

urlretrieve()의 캐싱 기능은 누군가가 만료 시간 헤더의 적절한 처리를 해킹할 시간을 찾을 때까지 비활성화되었습니다.

특정 URL이 캐시에 있는지를 조회하는 함수가 있어야 합니다.

이전 버전과의 호환성을 위해, URL이 로컬 파일을 가리키는 것으로 보이지만 파일을 열 수 없으면, FTP 프로토콜을 사용하여 URL을 다시 해석합니다. 이로 인해 때때로 혼란스러운 에러 메시지가 발생할 수 있습니다.

The urlopen() and urlretrieve() functions can cause arbitrarily long delays while waiting for a network connection to be set up. This means that it is difficult to build an interactive web client using these functions without using threads.

urlopen()이나 urlretrieve()가 반환한 데이터는 서버가 반환한 원시 데이터입니다. 바이너리 데이터 (가령 이미지), 평문 텍스트 또는 (예를 들어) HTML일 수 있습니다. HTTP 프로토콜은 응답 헤더에 유형 정보를 제공하는데, Content-Type 헤더를 통해 검사할 수 있습니다. 반환된 데이터가 HTML이면, html.parser 모듈을 사용하여 구문 분석할 수 있습니다.

The code handling the FTP protocol cannot differentiate between a file and a directory. This can lead to unexpected behavior when attempting to read a URL that points to a file that is not accessible. If the URL ends in a /, it is assumed to refer to a directory and will be handled accordingly. But if an attempt to read a file leads to a 550 error (meaning the URL cannot be found or is not accessible, often for permission reasons), then the path is treated as a directory in order to handle the case when a directory is specified by a URL but the trailing / has been left off. This can cause misleading results when you try to fetch a file whose read permissions make it inaccessible; the FTP code will try to read it, fail with a 550 error, and then perform a directory listing for the unreadable file. If fine-grained control is needed, consider using the ftplib module.

urllib.response — urllib가 사용하는 응답 클래스

urllib.response 모듈은 read()와 readline()을 포함하여 최소한의 파일류 인터페이스를 정의하는 함수와 클래스를 정의합니다. 이 모듈에 의해 정의된 함수는 urllib.request 모듈에 의해 내부적으로 사용됩니다. 일반적인 응답 객체는 urllib.response.addinfourl 인스턴스입니다:

class urllib.response.addinfourl

url

가져온 자원의 URL, 일반적으로 리디렉션을 따라갔는지 판별하는 데 사용됩니다.

headers

EmailMessage 인스턴스 형식으로 응답의 헤더를 반환합니다.

status

Added in version 3.9.

서버가 반환한 상태 코드.

geturl()

버전 3.9부터 폐지됨: 폐지되었고 url로 대체되었습니다.

info()

버전 3.9부터 폐지됨: 폐지되었고 headers로 대체되었습니다.

code

버전 3.9부터 폐지됨: 폐지되었고 status로 대체되었습니다.

getcode()

버전 3.9부터 폐지됨: 폐지되었고 status로 대체되었습니다.

urllib.parse — Parse URLs into components

소스 코드: Lib/urllib/parse.py [https://github.com/python/cpython/tree/main/Lib/urllib/parse.py]

이 모듈은 URL(Uniform Resource Locator) 문자열을 구성 요소(주소 지정 체계, 네트워크 위치, 경로 등)로 분리하고, 구성 요소를 다시 URL 문자열로 결합하고, “상대 URL”을 주어진 “기본 URL”에 따라 절대 URL로 변환하는 표준 인터페이스를 정의합니다.

The module has been designed to match the internet RFC on Relative Uniform Resource Locators. It supports the following URL schemes: file, ftp, gopher, hdl, http, https, imap, itms-services, mailto, mms, news, nntp, prospero, rsync, rtsp, rtsps, rtspu, sftp, shttp, sip, sips, snews, svn, svn+ssh, telnet, wais, ws, wss.

CPython 구현 상세: The inclusion of the itms-services URL scheme can prevent an app from passing Apple’s App Store review process for the macOS and iOS App Stores. Handling for the itms-services scheme is always removed on iOS; on macOS, it may be removed if CPython has been built with the --with-app-store-compliance option.

urllib.parse 모듈은 두 가지 넓은 범주에 속하는 함수들을 정의합니다: URL 구문 분석과 URL 인용(quoting). 이에 대해서는 다음 섹션에서 자세히 설명합니다.

This module’s functions use the deprecated term netloc (or net_loc), which was introduced in RFC 1808 [https://datatracker.ietf.org/doc/html/rfc1808.html]. However, this term has been obsoleted by RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html], which introduced the term authority as its replacement. The use of netloc is continued for backward compatibility.

URL 구문 분석

URL 구문 분석 함수는 URL 문자열을 구성 요소로 분할하거나 URL 구성 요소를 URL 문자열로 결합하는 데 중점을 둡니다.

urllib.parse.urlparse(urlstring, scheme='', allow_fragments=True)

URL을 6개의 구성 요소로 구문 분석하여, 6개 항목 네임드 튜플을 반환합니다. 이는 URL의 일반적인 구조에 해당합니다: scheme://netloc/path;parameters?query#fragment. 각 튜플 항목은 문자열이며 비어있을 수 있습니다. 구성 요소는 더 작은 부분으로 나뉘지 않으며 (예를 들어 네트워크 위치는 단일 문자열입니다), % 이스케이프는 확장되지 않습니다. 위에 표시된 분리 문자는 path 구성 요소의 선행 슬래시를 제외하고는 결과의 일부가 아니며 존재하면 유지됩니다. 예를 들면:

>>> from urllib.parse import urlparse
>>> urlparse("scheme://netloc/path;parameters?query#fragment")
ParseResult(scheme='scheme', netloc='netloc', path='/path;parameters', params='',
            query='query', fragment='fragment')
>>> o = urlparse("http://docs.python.org:80/3/library/urllib.parse.html?"
...              "highlight=params#url-parsing")
>>> o
ParseResult(scheme='http', netloc='docs.python.org:80',
            path='/3/library/urllib.parse.html', params='',
            query='highlight=params', fragment='url-parsing')
>>> o.scheme
'http'
>>> o.netloc
'docs.python.org:80'
>>> o.hostname
'docs.python.org'
>>> o.port
80
>>> o._replace(fragment="").geturl()
'http://docs.python.org:80/3/library/urllib.parse.html?highlight=params'

RFC 1808 [https://datatracker.ietf.org/doc/html/rfc1808.html]의 문법 명세에 따라, urlparse는 ‘//’ 로 올바르게 도입되었을 때만 netloc을 인식합니다. 그렇지 않으면 입력은 상대 URL인 것으로 간주하고 path 구성 요소로 시작합니다.

>>> from urllib.parse import urlparse
>>> urlparse('//www.cwi.nl:80/%7Eguido/Python.html')
ParseResult(scheme='', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
            params='', query='', fragment='')
>>> urlparse('www.cwi.nl/%7Eguido/Python.html')
ParseResult(scheme='', netloc='', path='www.cwi.nl/%7Eguido/Python.html',
            params='', query='', fragment='')
>>> urlparse('help/Python.html')
ParseResult(scheme='', netloc='', path='help/Python.html', params='',
            query='', fragment='')

scheme 인자는 URL이 지정하지 않은 경우에만 사용될 기본 주소 지정 체계를 제공합니다. 기본값 ''가 항상 허용되고 필요하면 자동으로 b''로 변환된다는 점을 제외하고, urlstring과 같은 형(텍스트나 바이트열)이어야 합니다.

allow_fragments 인자가 거짓이면, 프래그먼트 식별자는 인식되지 않습니다. 대신, path, parameters 또는 query 구성 요소의 일부로 구문 분석되고 fragment는 반환 값에서 빈 문자열로 설정됩니다.

반환 값은 네임드 튜플입니다. 즉, 다음과 같은 인덱스나 이름있는 어트리뷰트로 해당 항목에 액세스 할 수 있습니다:

어트리뷰트

인덱스

값

존재하지 않을 때의 값

scheme

0

URL 스킴 지정자

scheme 매개 변수

netloc

1

네트워크 위치 부분

빈 문자열

path

2

계층적 경로

빈 문자열

params

3

마지막 경로 요소의 파라미터

빈 문자열

query

4

쿼리 구성 요소

빈 문자열

fragment

5

프래그먼트 식별자

빈 문자열

username

사용자 이름

None

password

비밀번호

None

hostname

호스트 이름 (소문자)

None

port

존재하면, 정수로 표시되는 포트 번호

None

URL에 잘못된 포트가 지정된 경우 port 어트리뷰트를 읽으면 ValueError가 발생합니다. 결과 객체에 대한 자세한 내용은 구조화된 구문 분석 결과 섹션을 참조하십시오.

netloc 어트리뷰트에서 대괄호(square brackets)가 일치하지 않으면 ValueError가 발생합니다.

(IDNA 인코딩에서 사용되는) NFKC 정규화에서 /, ?, #, @ 또는 : 중 하나로 분해(decompose)되는 netloc 어트리뷰트의 문자는 ValueError를 발생시킵니다. 구문 분석하기 전에 URL이 분해(decompose)되면, 에러가 발생하지 않습니다.

모든 네임드 튜플의 경우와 마찬가지로, 서브 클래스는 특히 유용한 몇 가지 추가 메서드와 어트리뷰트를 갖습니다. 그러한 메서드 중 하나는 _replace()입니다. _replace() 메서드는 지정된 필드를 새로운 값으로 대체한 새로운 ParseResult 객체를 반환합니다.

>>> from urllib.parse import urlparse
>>> u = urlparse('//www.cwi.nl:80/%7Eguido/Python.html')
>>> u
ParseResult(scheme='', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
            params='', query='', fragment='')
>>> u._replace(scheme='http')
ParseResult(scheme='http', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
            params='', query='', fragment='')

경고

urlparse() does not perform validation. See URL parsing security for details.

버전 3.2에서 변경: IPv6 URL 구문 분석 기능이 추가되었습니다.

버전 3.3에서 변경: The fragment is now parsed for all URL schemes (unless allow_fragments is false), in accordance with RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]. Previously, an allowlist of schemes that support fragments existed.

버전 3.6에서 변경: 범위를 벗어난 포트 번호는 이제 None을 반환하는 대신 ValueError를 발생시킵니다.

버전 3.8에서 변경: NFKC 정규화에서 netloc 구문 분석에 영향을 주는 문자는 이제 ValueError를 발생시킵니다.

urllib.parse.parse_qs(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace', max_num_fields=None, separator='&')

문자열 인자(application/x-www-form-urlencoded 유형의 데이터)로 제공된 쿼리 문자열을 구문 분석합니다. 데이터는 딕셔너리로 반환됩니다. 딕셔너리 키는 고유한 쿼리 변수 이름이고 값은 각 이름의 값 리스트입니다.

선택적 인자 keep_blank_values는 퍼센트 인코딩된 쿼리의 빈 값을 빈 문자열로 처리해야 하는지를 나타내는 플래그입니다. 참값은 빈 값을 빈 문자열로 유지해야 함을 나타냅니다. 기본 거짓 값은 빈 값이 무시되고 포함되지 않은 것처럼 처리됨을 나타냅니다.

선택적 인자 strict_parsing은 구문 분석 에러 시 수행할 작업을 나타내는 플래그입니다. 거짓(기본값)이면, 에러가 조용히 무시됩니다. 참이면, 에러는 ValueError 예외를 발생시킵니다.

선택적 encoding과 errors 매개 변수는 bytes.decode() 메서드에서 받아들이는 것처럼 퍼센트 인코딩된 시퀀스를 유니코드 문자로 디코딩하는 방법을 지정합니다.

선택적 인자 max_num_fields는 읽을 최대 필드 수입니다. 설정되면, max_num_fields 필드보다 많은 것을 읽을 때 ValueError가 발생합니다.

선택적 인자 separator는 쿼리 인자를 구분하는 데 사용할 기호입니다. 기본값은 &입니다.

이러한 딕셔너리를 쿼리 문자열로 변환하려면 urllib.parse.urlencode() 함수를 (doseq 매개 변수를 True로 설정해서) 사용하십시오.

버전 3.2에서 변경: encoding과 errors 매개 변수를 추가합니다.

버전 3.8에서 변경: max_num_fields 매개 변수를 추가했습니다.

버전 3.10에서 변경: Added separator parameter with the default value of &. Python versions earlier than Python 3.10 allowed using both ; and & as query parameter separator. This has been changed to allow only a single separator key, with & as the default separator.

버전 3.14부터 폐지됨: Accepting objects with false values (like 0 and []) except empty strings and byte-like objects and None is now deprecated.

urllib.parse.parse_qsl(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace', max_num_fields=None, separator='&')

문자열 인자(application/x-www-form-urlencoded 유형의 데이터)로 제공된 쿼리 문자열을 구문 분석합니다. 데이터는 이름, 값 쌍의 리스트로 반환됩니다.

선택적 인자 keep_blank_values는 퍼센트 인코딩된 쿼리의 빈 값을 빈 문자열로 처리해야 하는지를 나타내는 플래그입니다. 참값은 빈 값을 빈 문자열로 유지해야 함을 나타냅니다. 기본 거짓 값은 빈 값이 무시되고 포함되지 않은 것처럼 처리됨을 나타냅니다.

선택적 인자 strict_parsing은 구문 분석 에러 시 수행할 작업을 나타내는 플래그입니다. 거짓(기본값)이면, 에러가 조용히 무시됩니다. 참이면, 에러는 ValueError 예외를 발생시킵니다.

선택적 encoding과 errors 매개 변수는 bytes.decode() 메서드에서 받아들이는 것처럼 퍼센트 인코딩된 시퀀스를 유니코드 문자로 디코딩하는 방법을 지정합니다.

선택적 인자 max_num_fields는 읽을 최대 필드 수입니다. 설정되면, max_num_fields 필드보다 많은 것을 읽을 때 ValueError가 발생합니다.

선택적 인자 separator는 쿼리 인자를 구분하는 데 사용할 기호입니다. 기본값은 &입니다.

이러한 쌍의 리스트를 쿼리 문자열로 변환하려면 urllib.parse.urlencode() 함수를 사용하십시오.

버전 3.2에서 변경: encoding과 errors 매개 변수를 추가합니다.

버전 3.8에서 변경: max_num_fields 매개 변수를 추가했습니다.

버전 3.10에서 변경: Added separator parameter with the default value of &. Python versions earlier than Python 3.10 allowed using both ; and & as query parameter separator. This has been changed to allow only a single separator key, with & as the default separator.

urllib.parse.urlunparse(parts)

urlparse()에 의해 반환된 튜플에서 URL을 구성합니다. parts 인자는 임의의 6개 항목 이터러블일 수 있습니다. 구문 분석된 원래 URL에 불필요한 구분자가 있는 경우 (예를 들어 비어있는 쿼리가 있는 ?; RFC는 이들이 동등하다고 말합니다) 약간 다르지만 동등한 URL이 만들어질 수 있습니다.

urllib.parse.urlsplit(urlstring, scheme='', allow_fragments=True)

이것은 urlparse()와 유사하지만, URL에서 파라미터를 분할하지 않습니다. URL의 path 부분의 각 세그먼트에 파라미터를 적용할 수 있는 최신 URL 문법(RFC 2396 [https://datatracker.ietf.org/doc/html/rfc2396.html]을 참조하십시오)이 필요하면 일반적으로 urlparse() 대신 사용해야 합니다. 경로 세그먼트와 파라미터를 분리하려면 별도의 함수가 필요합니다. 이 함수는 5개 항목 네임드 튜플을 반환합니다:

(addressing scheme, network location, path, query, fragment identifier).

반환 값은 네임드 튜플입니다, 항목은 인덱스나 이름 붙은 어트리뷰트로 액세스 할 수 있습니다:

어트리뷰트

인덱스

값

존재하지 않을 때의 값

scheme

0

URL 스킴 지정자

scheme 매개 변수

netloc

1

네트워크 위치 부분

빈 문자열

path

2

계층적 경로

빈 문자열

query

3

쿼리 구성 요소

빈 문자열

fragment

4

프래그먼트 식별자

빈 문자열

username

사용자 이름

None

password

비밀번호

None

hostname

호스트 이름 (소문자)

None

port

존재하면, 정수로 표시되는 포트 번호

None

URL에 잘못된 포트가 지정된 경우 port 어트리뷰트를 읽으면 ValueError가 발생합니다. 결과 객체에 대한 자세한 내용은 구조화된 구문 분석 결과 섹션을 참조하십시오.

netloc 어트리뷰트에서 대괄호(square brackets)가 일치하지 않으면 ValueError가 발생합니다.

(IDNA 인코딩에서 사용되는) NFKC 정규화에서 /, ?, #, @ 또는 : 중 하나로 분해(decompose)되는 netloc 어트리뷰트의 문자는 ValueError를 발생시킵니다. 구문 분석하기 전에 URL이 분해(decompose)되면, 에러가 발생하지 않습니다.

Following some of the WHATWG spec [https://url.spec.whatwg.org/#concept-basic-url-parser] that updates RFC 3986, leading C0 control and space characters are stripped from the URL. \n, \r and tab \t characters are removed from the URL at any position.

경고

urlsplit() does not perform validation. See URL parsing security for details.

버전 3.6에서 변경: 범위를 벗어난 포트 번호는 이제 None을 반환하는 대신 ValueError를 발생시킵니다.

버전 3.8에서 변경: NFKC 정규화에서 netloc 구문 분석에 영향을 주는 문자는 이제 ValueError를 발생시킵니다.

버전 3.10에서 변경: ASCII newline and tab characters are stripped from the URL.

버전 3.12에서 변경: Leading WHATWG C0 control and space characters are stripped from the URL.

urllib.parse.urlunsplit(parts)

urlsplit()에 의해 반환된 튜플 요소를 완전한 URL 문자열로 결합합니다. parts 인자는 임의의 5개 항목 이터러블일 수 있습니다. 구문 분석된 원래 URL에 불필요한 구분자가 있는 경우 (예를 들어 비어있는 쿼리가 있는 ?; RFC는 이들이 동등하다고 말합니다) 약간 다르지만 동등한 URL이 만들어질 수 있습니다.

urllib.parse.urljoin(base, url, allow_fragments=True)

“기본 URL”(base)을 다른 URL(url)과 결합하여 전체 (“절대”) URL을 구성합니다. 비형식적으로, 이것은 기본 URL의 구성 요소, 특히 주소 지정 체계, 네트워크 위치 및 경로(의 일부)를 사용하여 상대 URL에 누락된 구성 요소를 제공합니다. 예를 들면:

>>> from urllib.parse import urljoin
>>> urljoin('http://www.cwi.nl/%7Eguido/Python.html', 'FAQ.html')
'http://www.cwi.nl/%7Eguido/FAQ.html'

allow_fragments 인자는 urlparse()와 같은 의미와 기본값을 갖습니다.

참고

url이 절대 URL이면 (즉, //나 scheme://로 시작하면), url의 호스트명 및/또는 스킴이 결과에 나타납니다. 예를 들면:

>>> urljoin('http://www.cwi.nl/%7Eguido/Python.html',
...         '//www.python.org/%7Eguido')
'http://www.python.org/%7Eguido'

이런 동작을 원하지 않으면, url을 urlsplit()과 urlunsplit()으로 사전 처리하여 가능한 scheme과 netloc 부분을 제거하십시오.

경고

Because an absolute URL may be passed as the url parameter, it is generally not secure to use urljoin with an attacker-controlled url. For example in, urljoin("https://website.com/users/", username), if username can contain an absolute URL, the result of urljoin will be the absolute URL.

버전 3.5에서 변경: RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]에 정의된 의미론과 일치하도록 동작이 갱신되었습니다.

urllib.parse.urldefrag(url)

url에 프래그먼트 식별자가 포함되면, 프래그먼트 식별자 없는 url의 수정된 버전과 프래그먼트 식별자를 별도의 문자열로 반환합니다. url에 프래그먼트 식별자가 없으면, 수정되지 않은 url과 빈 문자열을 반환합니다.

반환 값은 네임드 튜플입니다, 항목은 인덱스나 이름 붙은 어트리뷰트로 액세스 할 수 있습니다:

어트리뷰트

인덱스

값

존재하지 않을 때의 값

url

0

프래그먼트 없는 URL

빈 문자열

fragment

1

프래그먼트 식별자

빈 문자열

결과 객체에 대한 자세한 정보는 섹션 구조화된 구문 분석 결과를 참조하십시오.

버전 3.2에서 변경: 결과는 단순한 2-튜플이 아닌 구조화된 객체입니다.

urllib.parse.unwrap(url)

래핑 된 URL(즉, <URL:scheme://host/path>, <scheme://host/path>, URL:scheme://host/path 또는 scheme://host/path 형식의 문자열)에서 URL을 추출합니다. url이 래핑 된 URL이 아니면, 변경 없이 반환됩니다.

URL parsing security

The urlsplit() and urlparse() APIs do not perform validation of inputs. They may not raise errors on inputs that other applications consider invalid. They may also succeed on some inputs that might not be considered URLs elsewhere. Their purpose is for practical functionality rather than purity.

Instead of raising an exception on unusual input, they may instead return some component parts as empty strings. Or components may contain more than perhaps they should.

We recommend that users of these APIs where the values may be used anywhere with security implications code defensively. Do some verification within your code before trusting a returned component part. Does that scheme make sense? Is that a sensible path? Is there anything strange about that hostname? etc.

What constitutes a URL is not universally well defined. Different applications have different needs and desired constraints. For instance the living WHATWG spec [https://url.spec.whatwg.org/#concept-basic-url-parser] describes what user facing web clients such as a web browser require. While RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html] is more general. These functions incorporate some aspects of both, but cannot be claimed compliant with either. The APIs and existing user code with expectations on specific behaviors predate both standards leading us to be very cautious about making API behavior changes.

ASCII로 인코딩된 바이트열 구문 분석

URL 구문 분석 함수는 원래 문자열에서만 작동하도록 설계되었습니다. 실제로는, 적절히 인용되고 인코딩된 URL을 ASCII 바이트 시퀀스로 조작할 수 있으면 유용합니다. 따라서, 이 모듈의 URL 구문 분석 함수는 모두 str 객체 외에 bytes와 bytearray 객체에서 작동합니다.

str 데이터가 전달되면, 결과에는 str 데이터만 포함됩니다. bytes나 bytearray 데이터가 전달되면, 결과에는 bytes 데이터만 포함됩니다.

단일 함수 호출에서 str 데이터를 bytes나 bytearray와 혼합하려고 시도하면 TypeError가 발생하는 반면, 비 ASCII 바이트 값을 전달하면 UnicodeDecodeError가 트리거 됩니다.

str과 bytes 간에 결과 객체를 쉽게 변환 할 수 있도록, URL 구문 분석 함수의 모든 반환 값은 encode() 메서드(결과에 str 데이터가 포함될 때)나 decode() 메서드(결과에 bytes 데이터가 포함될 때)를 제공합니다. 이러한 메서드의 서명은 해당 str와 bytes 메서드의 서명과 일치합니다 (기본 인코딩이 'utf-8'가 아니라 'ascii'라는 점은 예외입니다). 각각은 bytes 데이터(encode() 메서드의 경우)나 str 데이터(decode() 메서드의 경우)를 포함하는 해당 형의 값을 생성합니다.

ASCII가 아닌 데이터를 포함할 수 있는 잘못 인용된 URL에서 작동할 가능성이 있는 응용 프로그램은 URL 구문 분석 메서드를 호출하기 전에 바이트열에서 문자로 자체 디코딩을 수행할 필요가 있습니다.

이 섹션에서 설명하는 동작은 URL 구문 분석 함수에만 적용됩니다. URL 인용 함수는 개별 URL 인용 함수의 설명서에 기술된 대로 바이트 시퀀스를 생성하거나 소비할 때 자체 규칙을 사용합니다.

버전 3.2에서 변경: URL 구문 분석 함수는 이제 ASCII 인코딩된 바이트 시퀀스를 받아들입니다.

구조화된 구문 분석 결과

urlparse(), urlsplit() 및 urldefrag() 함수의 결과 객체는 tuple 형의 서브 클래스입니다. 이 서브 클래스는 해당 함수에 대한 설명서에 나열된 어트리뷰트, 이전 섹션에서 설명한 인코딩과 디코딩 지원 및 추가 메서드를 추가합니다:

urllib.parse.SplitResult.geturl()

원래 URL의 재결합된 버전을 문자열로 반환합니다. 스킴이 소문자로 정규화되고 빈 구성 요소가 삭제될 수 있다는 점에서 원래 URL과 다를 수 있습니다. 특히, 빈 파라미터, 쿼리 및 프래그먼트 식별자가 제거됩니다.

urldefrag() 결과의 경우, 빈 프래그먼트 식별자만 제거됩니다. urlsplit()과 urlparse() 결과의 경우, 이 메서드가 반환한 URL에 대해 언급된 모든 변경 사항이 적용됩니다.

이 메서드의 결과는 원래 구문 분석 함수를 통해 다시 전달될 때 변경되지 않은 상태로 유지됩니다:

>>> from urllib.parse import urlsplit
>>> url = 'HTTP://www.Python.org/doc/#'
>>> r1 = urlsplit(url)
>>> r1.geturl()
'http://www.Python.org/doc/'
>>> r2 = urlsplit(r1.geturl())
>>> r2.geturl()
'http://www.Python.org/doc/'

다음 클래스는 str 객체에서 작동할 때 구조화된 구문 분석 결과의 구현을 제공합니다:

class urllib.parse.DefragResult(url, fragment)

str 데이터를 포함하는 urldefrag() 결과의 구상 클래스. encode() 메서드는 DefragResultBytes 인스턴스를 반환합니다.

Added in version 3.2.

class urllib.parse.ParseResult(scheme, netloc, path, params, query, fragment)

str 데이터를 포함하는 urlparse() 결과의 구상 클래스. encode() 메서드는 ParseResultBytes 인스턴스를 반환합니다.

class urllib.parse.SplitResult(scheme, netloc, path, query, fragment)

str 데이터를 포함하는 urlsplit() 결과의 구상 클래스. encode() 메서드는 SplitResultBytes 인스턴스를 반환합니다.

다음 클래스는 bytes나 bytearray 객체에서 작동할 때 구문 분석 결과의 구현을 제공합니다:

class urllib.parse.DefragResultBytes(url, fragment)

bytes 데이터를 포함하는 urldefrag() 결과의 구상 클래스. decode() 메서드는 DefragResult 인스턴스를 반환합니다.

Added in version 3.2.

class urllib.parse.ParseResultBytes(scheme, netloc, path, params, query, fragment)

bytes 데이터를 포함하는 urlparse() 결과의 구상 클래스. decode() 메서드는 ParseResult 인스턴스를 반환합니다.

Added in version 3.2.

class urllib.parse.SplitResultBytes(scheme, netloc, path, query, fragment)

bytes 데이터를 포함하는 urlsplit() 결과의 구상 클래스. decode() 메서드는 SplitResult 인스턴스를 반환합니다.

Added in version 3.2.

URL 인용

URL 인용(quoting) 함수는 특수 문자를 인용하고 비 ASCII 텍스트를 적절히 인코딩하여 프로그램 데이터를 취해서 URL 구성 요소로 안전하게 사용할 수 있도록 하는 데 중점을 둡니다. 또한 해당 작업이 위의 URL 구문 분석 함수로 처리되지 않는 경우 URL 구성 요소의 내용에서 원래 데이터를 다시 만들기 위해 이러한 작업을 뒤집는 것도 지원합니다.

urllib.parse.quote(string, safe='/', encoding=None, errors=None)

Replace special characters in string using the %xx escape. Letters, digits, and the characters '_.-~' are never quoted. By default, this function is intended for quoting the path section of a URL. The optional safe parameter specifies additional ASCII characters that should not be quoted — its default value is '/'.

string은 str이나 bytes 객체일 수 있습니다.

버전 3.7에서 변경: URL 문자열 인용을 RFC 2396 [https://datatracker.ietf.org/doc/html/rfc2396.html]에서 RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html]으로 옮겼습니다. “~”는 이제 예약되지 않은 문자 집합에 포함됩니다.

선택적 encoding과 errors 매개 변수는 str.encode() 메서드에서 받아들이는 것처럼 비 ASCII 문자를 처리하는 방법을 지정합니다. encoding의 기본값은 'utf-8'입니다. errors의 기본값은 'strict'로, 지원되지 않는 문자는 UnicodeEncodeError를 발생시킴을 의미합니다. string이 bytes이면 encoding과 errors를 제공해서는 안 됩니다, 그렇지 않으면 TypeError가 발생합니다.

quote(string, safe, encoding, errors)는 quote_from_bytes(string.encode(encoding, errors), safe)와 동등함에 유의하십시오.

예: quote('/El Niño/')는 '/El%20Ni%C3%B1o/'를 산출합니다.

urllib.parse.quote_plus(string, safe='', encoding=None, errors=None)

quote()와 유사하지만, URL로 이동하기 위한 쿼리 문자열을 만들 때 HTML 폼값을 인용하는 데 필요한 대로 스페이스를 더하기 부호로 치환하기도 합니다. safe에 포함되지 않으면 원래 문자열의 더하기 부호가 이스케이프 됩니다. 또한 safe의 기본값은 '/'가 아닙니다.

예: quote_plus('/El Niño/')는 '%2FEl+Ni%C3%B1o%2F'를 산출합니다.

urllib.parse.quote_from_bytes(bytes, safe='/')

quote()와 유사하지만, str 대신 bytes 객체를 받아들이고, 문자열을 바이트열로 인코딩하지 않습니다.

예: quote_from_bytes(b'a&\xef')는 'a%26%EF'를 산출합니다.

urllib.parse.unquote(string, encoding='utf-8', errors='replace')

Replace %xx escapes with their single-character equivalent. The optional encoding and errors parameters specify how to decode percent-encoded sequences into Unicode characters, as accepted by the bytes.decode() method.

string은 str이나 bytes 객체일 수 있습니다.

encoding의 기본값은 'utf-8'입니다. errors의 기본값은 'replace'로, 유효하지 않은 시퀀스는 자리 표시자 문자(placeholder character)로 대체됩니다.

예: unquote('/El%20Ni%C3%B1o/')는 '/El Niño/'를 산출합니다.

버전 3.9에서 변경: string 매개 변수는 바이트열과 문자열 객체를 지원합니다 (이전에는 문자열만 지원했습니다).

urllib.parse.unquote_plus(string, encoding='utf-8', errors='replace')

unquote()와 유사하지만, HTML 폼값을 인용 해제할 때 요구되는 것처럼, 더하기 부호를 스페이스로 치환하기도 합니다.

string은 str이어야 합니다.

예: unquote_plus('/El+Ni%C3%B1o/')는 '/El Niño/'를 산출합니다.

urllib.parse.unquote_to_bytes(string)

Replace %xx escapes with their single-octet equivalent, and return a bytes object.

string은 str이나 bytes 객체일 수 있습니다.

str이면, string의 이스케이프 되지 않은 비 ASCII 문자는 UTF-8 바이트열로 인코딩됩니다.

예: unquote_to_bytes('a%26%EF')는 b'a&\xef'를 산출합니다.

urllib.parse.urlencode(query, doseq=False, safe='', encoding=None, errors=None, quote_via=quote_plus)

str이나 bytes 객체를 포함할 수 있는 매핑 객체나 두 요소 튜플의 시퀀스를 퍼센트 인코딩된 ASCII 텍스트 문자열로 변환합니다. 결과 문자열을 urlopen() 함수를 사용하여 POST 연산을 위한 data로 사용하려면, 바이트열로 인코딩해야 합니다, 그렇지 않으면 TypeError가 발생합니다.

결과 문자열은 '&' 문자로 구분된 일련의 key=value 쌍이고, 여기서 key와 value는 quote_via 함수를 사용하여 인용됩니다. 기본적으로, quote_plus()가 값을 인용하는 데 사용되는데, 스페이스는 '+' 문자로 인용되고 ‘/’ 문자는 %2F로 인코딩되어 GET 요청 표준(application/x-www-form-urlencoded)을 따름을 뜻합니다. quote_via로 전달될 수 있는 대체 함수는 quote()이며, 스페이스를 %20로 인코딩하고 ‘/’ 문자를 인코딩하지 않습니다. 무엇을 인용할지를 최대한 제어하려면, quote를 사용하고 safe의 값을 지정하십시오.

query 인자에 두 요소 튜플의 시퀀스가 사용될 때, 각 튜플의 첫 번째 요소는 키이고 두 번째 요소는 값입니다. 값 요소 자체는 시퀀스일 수 있으며, 이 경우 선택적 매개 변수 doseq가 True로 평가되면, '&'로 구분된 개별 key=value 쌍이 키에 대한 값 시퀀스의 각 요소에 대해 생성됩니다. 인코딩된 문자열의 파라미터 순서는 시퀀스의 파라미터 튜플 순서와 일치합니다.

safe, encoding 및 errors 매개 변수는 quote_via로 전달됩니다 (encoding과 errors 매개 변수는 쿼리 요소가 str일 때만 전달됩니다).

이 인코딩 프로세스를 뒤집기 위해, 쿼리 문자열을 파이썬 데이터 구조로 구문 분석하기 위해 이 모듈에서 parse_qs()와 parse_qsl()이 제공됩니다.

urllib.parse.urlencode() 메서드를 사용하여 URL의 쿼리 문자열이나 POST 요청의 데이터를 생성하는 방법을 알아보려면 urllib 예제를 참조하십시오.

버전 3.2에서 변경: query 매개 변수는 바이트열과 문자열 객체를 지원합니다.

버전 3.5에서 변경: Added the quote_via parameter.

버전 3.14부터 폐지됨: Accepting objects with false values (like 0 and []) except empty strings and byte-like objects and None is now deprecated.

더 보기

WHATWG [https://url.spec.whatwg.org/] - URL Living standard

Working Group for the URL Standard that defines URLs, domains, IP addresses, the application/x-www-form-urlencoded format, and their API.

RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html] - Uniform Resource Identifiers

이것이 현재 표준입니다 (STD66). urllib.parse 모듈에 대한 모든 변경 사항은 이를 준수해야 합니다. 특정 편차가 관찰될 수 있는데, 이는 대부분 이전 버전과의 호환성과 주요 브라우저에서 일반적으로 관찰되는 사실상의 구문 분석 요구 사항을 위한 것입니다.

RFC 2732 [https://datatracker.ietf.org/doc/html/rfc2732.html] - Format for Literal IPv6 Addresses in URL’s.

IPv6 URL의 구문 분석 요구 사항을 지정합니다.

RFC 2396 [https://datatracker.ietf.org/doc/html/rfc2396.html] - Uniform Resource Identifiers (URI): Generic Syntax

URN(Uniform Resource Names)과 URL(Uniform Resource Locator)에 대한 일반적인 문법 요구 사항을 설명하는 문서.

RFC 2368 [https://datatracker.ietf.org/doc/html/rfc2368.html] - The mailto URL scheme.

mailto URL 스킴에 대한 구문 분석 요구 사항.

RFC 1808 [https://datatracker.ietf.org/doc/html/rfc1808.html] - Relative Uniform Resource Locators

이 RFC는 경계 사례의 처리를 정의하는 꽤 많은 수의 “비정상적인 예”를 포함하여, 절대와 상대 URL을 결합하는 규칙을 포함합니다.

RFC 1738 [https://datatracker.ietf.org/doc/html/rfc1738.html] - Uniform Resource Locators (URL)

절대 URL의 형식 문법과 의미를 지정합니다.

urllib.error — Exception classes raised by urllib.request

소스 코드: Lib/urllib/error.py [https://github.com/python/cpython/tree/main/Lib/urllib/error.py]

urllib.error모듈은 urllib.request에 의해 발생하는 예외에 대한 예외 클래스를 정의합니다. 베이스 예외 클래스는 URLError입니다.

urllib.error에 의해 다음과 같은 예외가 적절하게 발생합니다.

exception urllib.error.URLError

처리기가 문제에 봉착하는 경우, 처리기는 해당 예외(또는 파생된 예외)를 발생시킵니다. 이 예외는 OSError의 서브 클래스입니다.

reason

이 에러가 발생한 원인입니다. 메시지 문자열이거나 다른 예외 인스턴스가 될 수 있습니다.

버전 3.3에서 변경: URLError used to be a subtype of IOError, which is now an alias of OSError.

exception urllib.error.HTTPError(url, code, msg, hdrs, fp)

HTTPError는 URLError의 서브 클래스로 예외 클래스이긴 하지만, 예외가 아닌 파일류 반환 값(urlopen()의 반환 값과 동일한 값)으로도 작동할 수 있습니다. 이 방법은 인증 요청 같은 독특한(exotic) HTTP 에러를 처리할 때 유용합니다.

url

Contains the request URL. An alias for filename attribute.

code

RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]에 정의된 HTTP 상태 코드입니다. 이 숫자 값은 http.server.BaseHTTPRequestHandler.responses에서 찾을 수 있는 상태 코드 딕셔너리에 있는 값에 해당합니다.

reason

This is usually a string explaining the reason for this error. An alias for msg attribute.

headers

The HTTP response headers for the HTTP request that caused the HTTPError. An alias for hdrs attribute.

Added in version 3.4.

fp

A file-like object where the HTTP error body can be read from.

exception urllib.error.ContentTooShortError(msg, content)

This exception is raised when the urlretrieve() function detects that the amount of the downloaded data is less than the expected amount (given by the Content-Length header).

content

The downloaded (and supposedly truncated) data.

urllib.robotparser — Parser for robots.txt

소스 코드: Lib/urllib/robotparser.py [https://github.com/python/cpython/tree/main/Lib/urllib/robotparser.py]

This module provides a single class, RobotFileParser, which answers questions about whether or not a particular user agent can fetch a URL on the web site that published the robots.txt file. For more details on the structure of robots.txt files, see http://www.robotstxt.org/orig.html.

class urllib.robotparser.RobotFileParser(url='')

이 클래스는 url에 있는 robots.txt 파일을 읽고, 구문 분석하고, 그에 대한 질문에 대답하는 메서드를 제공합니다.

set_url(url)

robots.txt 파일을 가리키는 URL을 설정합니다.

read()

robots.txt URL을 읽어서 구문 분석기에 넘깁니다.

parse(lines)

lines 인자를 구문 분석합니다.

can_fetch(useragent, url)

구문 분석된 robots.txt 파일에 포함된 규칙에 따라, useragent가 url를 가져올 수 있으면 True를 반환합니다.

mtime()

robots.txt 파일을 마지막으로 가져온 시간을 반환합니다. 이것은 새 robots.txt 파일을 주기적으로 확인해야 하는 장기 실행 웹 스파이더에 유용합니다.

modified()

robots.txt 파일을 마지막으로 가져온 시간을 현재 시각으로 설정합니다.

crawl_delay(useragent)

robots.txt에서 해당 useragent에 대한 Crawl-delay 파라미터의 값을 반환합니다. 해당 파라미터가 없거나, 지정된 useragent에 적용되지 않거나, 이 파라미터에 대한 robots.txt 항목이 잘못된 구문이면 None을 반환합니다.

Added in version 3.6.

request_rate(useragent)

robots.txt에서 Request-rate 파라미터의 내용을 네임드 튜플 RequestRate(requests, seconds)로 반환합니다. 해당 파라미터가 없거나, 지정된 useragent에 적용되지 않거나, 이 파라미터에 대한 robots.txt 항목이 잘못된 구문이면 None을 반환합니다.

Added in version 3.6.

site_maps()

robots.txt에서 Sitemap 매개 변수의 내용을 list() 형식으로 반환합니다. 해당 매개 변수가 없거나 robots.txt의 이 매개 변수 항목이 잘못된 문법이면 None을 반환합니다.

Added in version 3.8.

다음 예제는 RobotFileParser 클래스의 기본 사용을 보여줍니다:

>>> import urllib.robotparser
>>> rp = urllib.robotparser.RobotFileParser()
>>> rp.set_url("http://www.musi-cal.com/robots.txt")
>>> rp.read()
>>> rrate = rp.request_rate("*")
>>> rrate.requests
3
>>> rrate.seconds
20
>>> rp.crawl_delay("*")
6
>>> rp.can_fetch("*", "http://www.musi-cal.com/cgi-bin/search?city=San+Francisco")
False
>>> rp.can_fetch("*", "http://www.musi-cal.com/")
True

http — HTTP modules

소스 코드: Lib/http/__init__.py [https://github.com/python/cpython/tree/main/Lib/http/__init__.py]

http는 하이퍼텍스트 전송 프로토콜로 작업 하기 위한 여러 모듈을 수집하는 패키지입니다:

http.client는 저수준 HTTP 프로토콜 클라이언트입니다. 고수준의 URL 열기는 urllib.request를 사용합니다

http.server는 socketserver에 기반을 둔 기본적인 HTTP 서버 클래스를 포함합니다

http.cookies는 쿠키를 사용하여 상태 관리를 구현하는 유틸리티가 있습니다

http.cookiejar는 쿠키의 지속성을 제공합니다

The http module also defines the following enums that help you work with http related code:

class http.HTTPStatus

Added in version 3.5.

HTTP 상태 코드, 이유 구문 그리고 긴 영문 설명의 집합을 정의하는 enum.IntEnum의 서브 클래스입니다.

사용법:

>>> from http import HTTPStatus
>>> HTTPStatus.OK
HTTPStatus.OK
>>> HTTPStatus.OK == 200
True
>>> HTTPStatus.OK.value
200
>>> HTTPStatus.OK.phrase
'OK'
>>> HTTPStatus.OK.description
'Request fulfilled, document follows'
>>> list(HTTPStatus)
[HTTPStatus.CONTINUE, HTTPStatus.SWITCHING_PROTOCOLS, ...]

HTTP 상태 코드

Supported, IANA-registered status codes [https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml] available in http.HTTPStatus are:

코드

열거 이름

세부 사항

100

CONTINUE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.2.1

101

SWITCHING_PROTOCOLS

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.2.2

102

PROCESSING

WebDAV RFC 2518 [https://datatracker.ietf.org/doc/html/rfc2518.html], 섹션 10.1

103

EARLY_HINTS

힌트를 나타내는 HTTP 상태 코드 RFC 8297 [https://datatracker.ietf.org/doc/html/rfc8297.html]

200

OK

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.1

201

CREATED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.2

202

ACCEPTED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.3

203

NON_AUTHORITATIVE_INFORMATION

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.4

204

NO_CONTENT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.5

205

RESET_CONTENT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.6

206

PARTIAL_CONTENT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.3.7

207

MULTI_STATUS

WebDAV RFC 4918 [https://datatracker.ietf.org/doc/html/rfc4918.html], 섹션 11.1

208

ALREADY_REPORTED

WebDAV 바인딩 확장 RFC 5842 [https://datatracker.ietf.org/doc/html/rfc5842.html], 섹션 7.1 (실험적)

226

IM_USED

HTTP의 델타 인코딩 RFC 3229 [https://datatracker.ietf.org/doc/html/rfc3229.html], 섹션 10.4.1

300

MULTIPLE_CHOICES

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.1

301

MOVED_PERMANENTLY

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.2

302

FOUND

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.3

303

SEE_OTHER

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.4

304

NOT_MODIFIED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.5

305

USE_PROXY

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.6

307

TEMPORARY_REDIRECT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.8

308

PERMANENT_REDIRECT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.4.9

400

BAD_REQUEST

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.1

401

UNAUTHORIZED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.2

402

PAYMENT_REQUIRED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.3

403

FORBIDDEN

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.4

404

NOT_FOUND

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.5

405

METHOD_NOT_ALLOWED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.6

406

NOT_ACCEPTABLE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.7

407

PROXY_AUTHENTICATION_REQUIRED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.8

408

REQUEST_TIMEOUT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.9

409

CONFLICT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.10

410

GONE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.11

411

LENGTH_REQUIRED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.12

412

PRECONDITION_FAILED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.13

413

CONTENT_TOO_LARGE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.14

414

URI_TOO_LONG

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.15

415

UNSUPPORTED_MEDIA_TYPE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.16

416

RANGE_NOT_SATISFIABLE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.17

417

EXPECTATION_FAILED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.18

418

IM_A_TEAPOT

HTCPCP/1.0 RFC 2324 [https://datatracker.ietf.org/doc/html/rfc2324.html], 섹션 2.3.2

421

MISDIRECTED_REQUEST

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.20

422

UNPROCESSABLE_CONTENT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.21

423

LOCKED

WebDAV RFC 4918 [https://datatracker.ietf.org/doc/html/rfc4918.html], 섹션 11.3

424

FAILED_DEPENDENCY

WebDAV RFC 4918 [https://datatracker.ietf.org/doc/html/rfc4918.html], 섹션 11.4

425

TOO_EARLY

HTTP에서 초기 데이터(Early Data) 사용 RFC 8470 [https://datatracker.ietf.org/doc/html/rfc8470.html]

426

UPGRADE_REQUIRED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.5.22

428

PRECONDITION_REQUIRED

추가 HTTP 상태 코드 RFC 6585 [https://datatracker.ietf.org/doc/html/rfc6585.html]

429

TOO_MANY_REQUESTS

추가 HTTP 상태 코드 RFC 6585 [https://datatracker.ietf.org/doc/html/rfc6585.html]

431

REQUEST_HEADER_FIELDS_TOO_LARGE

추가 HTTP 상태 코드 RFC 6585 [https://datatracker.ietf.org/doc/html/rfc6585.html]

451

UNAVAILABLE_FOR_LEGAL_REASONS

법적 장애를 보고하는 HTTP 상태 코드 RFC 7725 [https://datatracker.ietf.org/doc/html/rfc7725.html]

500

INTERNAL_SERVER_ERROR

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.1

501

NOT_IMPLEMENTED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.2

502

BAD_GATEWAY

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.3

503

SERVICE_UNAVAILABLE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.4

504

GATEWAY_TIMEOUT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.5

505

HTTP_VERSION_NOT_SUPPORTED

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15.6.6

506

VARIANT_ALSO_NEGOTIATES

HTTP의 투명한 콘텐츠 협상 RFC 2295 [https://datatracker.ietf.org/doc/html/rfc2295.html], 섹션 8.1 (실험적)

507

INSUFFICIENT_STORAGE

WebDAV RFC 4918 [https://datatracker.ietf.org/doc/html/rfc4918.html], 섹션 11.5

508

LOOP_DETECTED

WebDAV 바인딩 확장 RFC 5842 [https://datatracker.ietf.org/doc/html/rfc5842.html], 섹션 7.2 (실험적)

510

NOT_EXTENDED

HTTP 확장 프레임워크 RFC 2774 [https://datatracker.ietf.org/doc/html/rfc2774.html], 섹션 7 (실험적)

511

NETWORK_AUTHENTICATION_REQUIRED

추가 HTTP 상태 코드 RFC 6585 [https://datatracker.ietf.org/doc/html/rfc6585.html], 섹션 6

이전 버전과의 호환성을 유지하기 위해 열거값은 http.client 모듈에 상수 형태로도 있습니다. 열거명과 상수명은 동일합니다 (즉, http.HTTPStatus.OK는 http.client.OK로도 사용 가능합니다).

버전 3.7에서 변경: 421 MISDIRECTED_REQUEST 상태 코드 추가.

Added in version 3.8: 451 UNAVAILABLE_FOR_LEGAL_REASONS 상태 코드가 추가.

Added in version 3.9: 103 EARLY_HINTS, 418 IM_A_TEAPOT 및 425 TOO_EARLY 상태 코드가 추가되었습니다.

버전 3.13에서 변경: Implemented RFC9110 naming for status constants. Old constant names are preserved for backwards compatibility.

HTTP status category

Added in version 3.12.

The enum values have several properties to indicate the HTTP status category:

Property

Indicates that

세부 사항

is_informational

100 <= status <= 199

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15

is_success

200 <= status <= 299

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15

is_redirection

300 <= status <= 399

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15

is_client_error

400 <= status <= 499

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15

is_server_error

500 <= status <= 599

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 15

사용법:

>>> from http import HTTPStatus
>>> HTTPStatus.OK.is_success
True
>>> HTTPStatus.OK.is_client_error
False

class http.HTTPMethod

Added in version 3.11.

A subclass of enum.StrEnum that defines a set of HTTP methods and descriptions written in English.

사용법:

>>> from http import HTTPMethod
>>>
>>> HTTPMethod.GET
<HTTPMethod.GET>
>>> HTTPMethod.GET == 'GET'
True
>>> HTTPMethod.GET.value
'GET'
>>> HTTPMethod.GET.description
'Retrieve the target.'
>>> list(HTTPMethod)
[<HTTPMethod.CONNECT>,
 <HTTPMethod.DELETE>,
 <HTTPMethod.GET>,
 <HTTPMethod.HEAD>,
 <HTTPMethod.OPTIONS>,
 <HTTPMethod.PATCH>,
 <HTTPMethod.POST>,
 <HTTPMethod.PUT>,
 <HTTPMethod.TRACE>]

HTTP methods

Supported, IANA-registered methods [https://www.iana.org/assignments/http-methods/http-methods.xhtml] available in http.HTTPMethod are:

Method

열거 이름

세부 사항

GET

GET

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.1

HEAD

HEAD

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.2

POST

POST

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.3

PUT

PUT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.4

DELETE

DELETE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.5

CONNECT

CONNECT

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.6

OPTIONS

OPTIONS

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.7

TRACE

TRACE

HTTP Semantics RFC 9110 [https://datatracker.ietf.org/doc/html/rfc9110.html], Section 9.3.8

PATCH

PATCH

HTTP/1.1 RFC 5789 [https://datatracker.ietf.org/doc/html/rfc5789.html]

http.client — HTTP protocol client

소스 코드: Lib/http/client.py [https://github.com/python/cpython/tree/main/Lib/http/client.py]

This module defines classes that implement the client side of the HTTP and HTTPS protocols. It is normally not used directly — the module urllib.request uses it to handle URLs that use HTTP and HTTPS.

더 보기

The Requests package [https://requests.readthedocs.io/en/latest/] is recommended for a higher-level HTTP client interface.

참고

HTTPS 지원은 파이썬이 SSL 지원으로 컴파일된 경우에만 사용 가능합니다 (ssl 모듈을 통해).

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

이 모듈은 다음과 같은 클래스를 제공합니다:

class http.client.HTTPConnection(host, port=None, [timeout, ]source_address=None, blocksize=8192)

An HTTPConnection instance represents one transaction with an HTTP server. It should be instantiated by passing it a host and optional port number. If no port number is passed, the port is extracted from the host string if it has the form host:port, else the default HTTP port (80) is used. If the optional timeout parameter is given, blocking operations (like connection attempts) will timeout after that many seconds (if it is not given, the global default timeout setting is used). The optional source_address parameter may be a tuple of a (host, port) to use as the source address the HTTP connection is made from. The optional blocksize parameter sets the buffer size in bytes for sending a file-like message body.

예를 들어, 다음 호출은 모두 같은 호스트와 포트에 있는 서버에 연결하는 인스턴스를 만듭니다:

>>> h1 = http.client.HTTPConnection('www.python.org')
>>> h2 = http.client.HTTPConnection('www.python.org:80')
>>> h3 = http.client.HTTPConnection('www.python.org', 80)
>>> h4 = http.client.HTTPConnection('www.python.org', 80, timeout=10)

버전 3.2에서 변경: source_address가 추가되었습니다.

버전 3.4에서 변경: The strict parameter was removed. HTTP 0.9-style “Simple Responses” are no longer supported.

버전 3.7에서 변경: blocksize 매개 변수가 추가되었습니다.

class http.client.HTTPSConnection(host, port=None, *, [timeout, ]source_address=None, context=None, blocksize=8192)

보안 서버와의 통신에 SSL을 사용하는 HTTPConnection의 서브 클래스. 기본 포트는 443입니다. context가 지정되면, 다양한 SSL 옵션을 기술하는 ssl.SSLContext 인스턴스여야 합니다.

모범 사례에 대한 자세한 내용은 보안 고려 사항을 참조하십시오.

버전 3.2에서 변경: source_address, context 및 check_hostname이 추가되었습니다.

버전 3.2에서 변경: This class now supports HTTPS virtual hosts if possible (that is, if ssl.HAS_SNI is true).

버전 3.4에서 변경: strict 매개 변수가 제거되었습니다. HTTP 0.9 스타일 “간단한 응답”은 더는 지원되지 않습니다.

버전 3.4.3에서 변경: This class now performs all the necessary certificate and hostname checks by default. To revert to the previous, unverified, behavior ssl._create_unverified_context() can be passed to the context parameter.

버전 3.8에서 변경: 이 클래스는 이제 기본 context나 cert_file이 사용자 정의 context와 함께 전달될 때 TLS 1.3 ssl.SSLContext.post_handshake_auth를 활성화합니다.

버전 3.10에서 변경: This class now sends an ALPN extension with protocol indicator http/1.1 when no context is given. Custom context should set ALPN protocols with set_alpn_protocols().

버전 3.12에서 변경: The deprecated key_file, cert_file and check_hostname parameters have been removed.

class http.client.HTTPResponse(sock, debuglevel=0, method=None, url=None)

성공적으로 연결되면 반환되는 인스턴스의 클래스. 사용자가 직접 인스턴스화 하지 않습니다.

버전 3.4에서 변경: strict 매개 변수가 제거되었습니다. HTTP 0.9 스타일 “간단한 응답”은 더는 지원되지 않습니다.

이 모듈은 다음 함수를 제공합니다:

http.client.parse_headers(fp)

Parse the headers from a file pointer fp representing a HTTP request/response. The file has to be a BufferedIOBase reader (i.e. not text) and must provide a valid RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] style header.

이 함수는 헤더 필드를 담은 http.client.HTTPMessage 인스턴스를 반환하지만, 페이 로드는 반환하지 않습니다 (HTTPResponse.msg와 http.server.BaseHTTPRequestHandler.headers와 같습니다). 반환 후, 파일 포인터 fp는 HTTP 바디를 읽을 준비가 되었습니다.

참고

parse_headers()는 HTTP 메시지의 시작 줄을 구문 분석하지 않습니다; Name: value 줄만 구문 분석합니다. 파일은 이러한 필드 줄을 읽을 준비가 되어 있어야 해서, 함수를 호출하기 전에 첫 번째 줄이 이미 소비되었어야 합니다.

다음과 같은 예외가 적절하게 발생합니다:

exception http.client.HTTPException

이 모듈에 있는 다른 예외의 베이스 클래스입니다. Exception의 서브 클래스입니다.

exception http.client.NotConnected

HTTPException의 서브 클래스.

exception http.client.InvalidURL

포트가 제공되고 숫자가 아니거나 비어있을 때 발생하는 HTTPException의 서브 클래스.

exception http.client.UnknownProtocol

HTTPException의 서브 클래스.

exception http.client.UnknownTransferEncoding

HTTPException의 서브 클래스.

exception http.client.UnimplementedFileMode

HTTPException의 서브 클래스.

exception http.client.IncompleteRead

HTTPException의 서브 클래스.

exception http.client.ImproperConnectionState

HTTPException의 서브 클래스.

exception http.client.CannotSendRequest

ImproperConnectionState의 서브 클래스.

exception http.client.CannotSendHeader

ImproperConnectionState의 서브 클래스.

exception http.client.ResponseNotReady

ImproperConnectionState의 서브 클래스.

exception http.client.BadStatusLine

HTTPException의 서브 클래스. 이해하지 못하는 HTTP 상태 코드로 서버가 응답하면 발생합니다.

exception http.client.LineTooLong

HTTPException의 서브 클래스. 서버에서 HTTP 프로토콜로 너무 긴 줄이 수신되면 발생합니다.

exception http.client.RemoteDisconnected

ConnectionResetError와 BadStatusLine의 서브 클래스. HTTPConnection.getresponse()가 응답을 읽으려고 시도할 때 연결에서 아무런 데이터를 읽지 못하여, 원격 끝이 연결을 닫았음을 표시하면 발생합니다.

Added in version 3.5: 이전에는, BadStatusLine('')가 발생했습니다.

이 모듈에 정의된 상수는 다음과 같습니다:

http.client.HTTP_PORT

HTTP 프로토콜의 기본 포트 (항상 80).

http.client.HTTPS_PORT

HTTPS 프로토콜의 기본 포트 (항상 443).

http.client.responses

이 딕셔너리는 HTTP 1.1 상태 코드를 W3C 이름으로 매핑합니다.

예: http.client.responses[http.client.NOT_FOUND]는 'Not Found'입니다.

이 모듈에서 상수로 사용 가능한 HTTP 상태 코드 목록은 HTTP 상태 코드를 참조하십시오.

HTTPConnection 객체

HTTPConnection 인스턴스에는 다음과 같은 메서드가 있습니다:

HTTPConnection.request(method, url, body=None, headers={}, *, encode_chunked=False)

This will send a request to the server using the HTTP request method method and the request URI url. The provided url must be an absolute path to conform with RFC 2616 §5.1.2 [https://datatracker.ietf.org/doc/html/rfc2616.html#section-5.1.2] (unless connecting to an HTTP proxy server or using the OPTIONS or CONNECT methods).

body가 지정되면, 헤더가 완료된 후 지정된 데이터가 전송됩니다. str, 바이트열류 객체, 열린 파일 객체 또는 bytes의 이터러블일 수 있습니다. body가 문자열이면, HTTP의 기본값인 ISO-8859-1로 인코딩됩니다. 바이트열류 객체이면, 바이트열은 그대로 전송됩니다. 파일 객체이면, 파일의 내용이 전송됩니다; 이 파일 객체는 최소한 read() 메서드를 지원해야 합니다. 파일 객체가 io.TextIOBase의 인스턴스이면, read() 메서드에서 반환된 데이터는 ISO-8859-1로 인코딩되고, 그렇지 않으면 read()에서 반환된 데이터가 그대로 전송됩니다. body가 이터러블이면, 이터러블이 소진될 때까지 이터러블의 요소가 그대로 전송됩니다.

The headers argument should be a mapping of extra HTTP headers to send with the request. A Host header [https://datatracker.ietf.org/doc/html/rfc2616.html#section-14.23] must be provided to conform with RFC 2616 §5.1.2 [https://datatracker.ietf.org/doc/html/rfc2616.html#section-5.1.2] (unless connecting to an HTTP proxy server or using the OPTIONS or CONNECT methods).

headers에 Content-Length도 Transfer-Encoding도 없지만, 요청 바디가 있으면, 이 헤더 필드 중 하나가 자동으로 추가됩니다. body가 None이면, 바디를 기대하는 메서드(PUT, POST 및 PATCH)의 경우 Content-Length 헤더가 0으로 설정됩니다. body가 문자열이거나 파일이 아닌 바이트열류 객체이면, Content-Length 헤더가 그것의 길이로 설정됩니다. 다른 모든 형의 body(파일과 이터러블 일반)는 청크 인코딩되며 Content-Length 대신 Transfer-Encoding 헤더가 자동으로 설정됩니다.

encode_chunked 인자는 Transfer-Encoding이 headers에 지정된 경우에만 유효합니다. encode_chunked가 False이면, HTTPConnection 객체는 모든 인코딩이 호출하는 코드에서 처리된다고 가정합니다. True이면, 바디가 청크 인코딩됩니다.

For example, to perform a GET request to https://docs.python.org/3/:

>>> import http.client
>>> host = "docs.python.org"
>>> conn = http.client.HTTPSConnection(host)
>>> conn.request("GET", "/3/", headers={"Host": host})
>>> response = conn.getresponse()
>>> print(response.status, response.reason)
200 OK

참고

청크 전송 인코딩은 HTTP 프로토콜 버전 1.1에 추가되었습니다. HTTP 서버가 HTTP 1.1을 처리하는 것으로 알려지지 않은 한, 호출자는 Content-Length를 지정하거나, 바디 표현으로 str이나 파일이 아닌 바이트열류 객체를 전달해야 합니다.

버전 3.2에서 변경: body는 이제 이터러블일 수 있습니다.

버전 3.6에서 변경: Content-Length도 Transfer-Encoding도 headers에 설정되지 않으면, 파일과 이터러블 body 객체는 이제 청크 인코딩됩니다. encode_chunked 인자가 추가되었습니다. 파일 객체의 Content-Length를 결정하려는 시도는 없습니다.

HTTPConnection.getresponse()

요청을 보낸 후에 서버에서 응답을 받기 위해 호출해야 합니다. HTTPResponse 인스턴스를 반환합니다.

참고

서버에 새 요청을 보내기 전에 전체 응답을 읽어야 함에 유의하십시오.

버전 3.5에서 변경: ConnectionError나 서브 클래스가 발생하면, 새 요청이 전송될 때 HTTPConnection 객체는 다시 연결할 준비가 됩니다.

HTTPConnection.set_debuglevel(level)

디버깅 수준을 설정합니다. 기본 디버그 수준은 0이며, 디버깅 출력이 인쇄되지 않음을 의미합니다. 0보다 큰 값을 지정하면 현재 정의된 모든 디버그 출력이 표준 출력으로 인쇄됩니다. debuglevel은 만들어지는 모든 새로운 HTTPResponse 객체로 전달됩니다.

Added in version 3.1.

HTTPConnection.set_tunnel(host, port=None, headers=None)

HTTP Connect 터널링(tunnelling)을 위한 host와 및 port를 설정합니다. 프락시 서버를 통해 연결을 실행할 수 있도록 합니다.

The host and port arguments specify the endpoint of the tunneled connection (i.e. the address included in the CONNECT request, not the address of the proxy server).

The headers argument should be a mapping of extra HTTP headers to send with the CONNECT request.

As HTTP/1.1 is used for HTTP CONNECT tunnelling request, as per the RFC [https://datatracker.ietf.org/doc/html/rfc7231#section-4.3.6], a HTTP Host: header must be provided, matching the authority-form of the request target provided as the destination for the CONNECT request. If a HTTP Host: header is not provided via the headers argument, one is generated and transmitted automatically.

예를 들어, 포트 8080에서 로컬로 실행되는 HTTPS 프락시 서버를 통해 터널링 하려면, 프락시 주소를 HTTPSConnection 생성자에 전달하고, 최종적으로 set_tunnel() 메서드에 도달하려는 호스트 주소를 전달합니다:

>>> import http.client
>>> conn = http.client.HTTPSConnection("localhost", 8080)
>>> conn.set_tunnel("www.python.org")
>>> conn.request("HEAD","/index.html")

Added in version 3.2.

버전 3.12에서 변경: HTTP CONNECT tunnelling requests use protocol HTTP/1.1, upgraded from protocol HTTP/1.0. Host: HTTP headers are mandatory for HTTP/1.1, so one will be automatically generated and transmitted if not provided in the headers argument.

HTTPConnection.get_proxy_response_headers()

Returns a dictionary with the headers of the response received from the proxy server to the CONNECT request.

If the CONNECT request was not sent, the method returns None.

Added in version 3.12.

HTTPConnection.connect()

객체가 만들어질 때 지정된 서버에 연결합니다. 기본적으로, 클라이언트가 이미 연결되지 않았다면 요청 시 자동으로 호출됩니다.

Raises an auditing event http.client.connect with arguments self, host, port.

HTTPConnection.close()

서버로의 연결을 닫습니다.

HTTPConnection.blocksize

파일류 메시지 바디를 보내기 위한 바이트 단위의 버퍼 크기.

Added in version 3.7.

As an alternative to using the request() method described above, you can also send your request step by step, by using the four functions below.

HTTPConnection.putrequest(method, url, skip_host=False, skip_accept_encoding=False)

서버에 연결한 후 첫 번째 호출이어야 합니다. method 문자열, url 문자열 및 HTTP 버전(HTTP/1.1)으로 구성된 줄을 서버로 보냅니다. Host:나 Accept-Encoding: 헤더의 자동 전송을 비활성화하려면 (예를 들어 추가 콘텐츠 인코딩을 허용하려면), False가 아닌 값으로 skip_host나 skip_accept_encoding을 지정하십시오.

HTTPConnection.putheader(header, argument[, ...])

RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] 스타일 헤더를 서버에 보냅니다. header, 콜론과 공백 및 첫 번째 인자로 구성된 줄을 서버로 보냅니다. 더 많은 인자가 제공되면, 탭과 인자로 구성된 연속 줄(continuation lines)이 전송됩니다.

HTTPConnection.endheaders(message_body=None, *, encode_chunked=False)

헤더의 끝을 알리는 빈 줄을 서버에 보냅니다. 선택적 message_body 인자를 사용하여 요청과 연관된 메시지 바디를 전달할 수 있습니다.

encode_chunked가 True이면, message_body의 각 이터레이션 결과는 RFC 7230 [https://datatracker.ietf.org/doc/html/rfc7230.html], 섹션 3.3.1에 지정된 대로 청크 인코딩됩니다. 데이터의 인코딩 방식은 message_body의 형에 따라 다릅니다. message_body가 버퍼 인터페이스를 구현하면, 인코딩은 단일 청크를 만듭니다. message_body가 collections.abc.Iterable이면, message_body의 각 이터레이션이 청크가 됩니다. message_body가 파일 객체이면, 각 .read() 호출마다 청크가 됩니다. 이 메서드는 message_body 직후에 청크 인코딩된 데이터의 끝을 자동으로 알립니다.

참고

청크 인코딩 명세로 인해, 이터레이터 바디에서 산출된 빈 청크는 청크 인코더에서 무시됩니다. 이는 형식이 잘못된 인코딩으로 인해 대상 서버의 요청 읽기가 조기에 종료되지 않도록 하려는 것입니다.

버전 3.6에서 변경: Added chunked encoding support and the encode_chunked parameter.

HTTPConnection.send(data)

서버로 data를 보냅니다. 이것은 endheaders() 메서드가 호출된 후, 그리고 getresponse()가 호출되기 전에만 직접 사용해야 합니다.

Raises an auditing event http.client.send with arguments self, data.

HTTPResponse 객체

HTTPResponse 인스턴스는 서버의 HTTP 응답을 감쌉니다. 요청 헤더와 엔티티 바디에 대한 액세스를 제공합니다. 응답은 이터러블 객체이며 with 문에서 사용할 수 있습니다.

버전 3.5에서 변경: io.BufferedIOBase 인터페이스가 이제 구현되었으며 이것의 모든 판독기(reader) 연산이 지원됩니다.

HTTPResponse.read([amt])

응답 바디나 다음 최대 amt 바이트를 읽고 반환합니다.

HTTPResponse.readinto(b)

응답 바디의 다음 최대 len(b) 바이트를 버퍼 b로 읽습니다. 읽은 바이트 수를 반환합니다.

Added in version 3.3.

HTTPResponse.getheader(name, default=None)

Return the value of the header name, or default if there is no header matching name. If there is more than one header with the name name, return all of the values joined by ‘, ‘. If default is any iterable other than a single string, its elements are similarly returned joined by commas.

HTTPResponse.getheaders()

(헤더, 값) 튜플의 리스트를 반환합니다.

HTTPResponse.fileno()

하부 소켓의 fileno를 반환합니다.

HTTPResponse.msg

응답 헤더를 포함하는 http.client.HTTPMessage 인스턴스. http.client.HTTPMessage는 email.message.Message의 서브 클래스입니다.

HTTPResponse.version

서버가 사용하는 HTTP 프로토콜 버전. HTTP/1.0의 경우 10, HTTP/1.1의 경우 11.

HTTPResponse.url

가져온 자원의 URL, 일반적으로 리디렉션을 따라갔는지 판별하는 데 사용됩니다.

HTTPResponse.headers

email.message.EmailMessage 인스턴스 형식의 응답 헤더.

HTTPResponse.status

서버가 반환한 상태 코드.

HTTPResponse.reason

서버가 반환한 이유 문구.

HTTPResponse.debuglevel

디버깅 훅. debuglevel이 0보다 크면, 응답을 읽고 구문 분석할 때 메시지가 표준 출력으로 인쇄됩니다.

HTTPResponse.closed

스트림이 닫혔으면 True입니다.

HTTPResponse.geturl()

버전 3.9부터 폐지됨: 폐지되었고 url로 대체되었습니다.

HTTPResponse.info()

버전 3.9부터 폐지됨: 폐지되었고 headers로 대체되었습니다.

HTTPResponse.getcode()

버전 3.9부터 폐지됨: 폐지되었고 status로 대체되었습니다.

예

GET 메서드를 사용하는 예제 세션은 다음과 같습니다:

>>> import http.client
>>> conn = http.client.HTTPSConnection("www.python.org")
>>> conn.request("GET", "/")
>>> r1 = conn.getresponse()
>>> print(r1.status, r1.reason)
200 OK
>>> data1 = r1.read()  # This will return entire content.
>>> # The following example demonstrates reading data in chunks.
>>> conn.request("GET", "/")
>>> r1 = conn.getresponse()
>>> while chunk := r1.read(200):
...     print(repr(chunk))
b'<!doctype html>\n<!--[if"...
...
>>> # Example of an invalid request
>>> conn = http.client.HTTPSConnection("docs.python.org")
>>> conn.request("GET", "/parrot.spam")
>>> r2 = conn.getresponse()
>>> print(r2.status, r2.reason)
404 Not Found
>>> data2 = r2.read()
>>> conn.close()

다음은 HEAD 메서드를 사용하는 예제 세션입니다. HEAD 메서드는 어떤 데이터도 반환하지 않음에 유의하십시오.

>>> import http.client
>>> conn = http.client.HTTPSConnection("www.python.org")
>>> conn.request("HEAD", "/")
>>> res = conn.getresponse()
>>> print(res.status, res.reason)
200 OK
>>> data = res.read()
>>> print(len(data))
0
>>> data == b''
True

Here is an example session that uses the POST method:

>>> import http.client, urllib.parse
>>> params = urllib.parse.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
>>> headers = {"Content-type": "application/x-www-form-urlencoded",
...            "Accept": "text/plain"}
>>> conn = http.client.HTTPConnection("bugs.python.org")
>>> conn.request("POST", "", params, headers)
>>> response = conn.getresponse()
>>> print(response.status, response.reason)
302 Found
>>> data = response.read()
>>> data
b'Redirecting to <a href="https://bugs.python.org/issue12524">https://bugs.python.org/issue12524</a>'
>>> conn.close()

Client side HTTP PUT requests are very similar to POST requests. The difference lies only on the server side where HTTP servers will allow resources to be created via PUT requests. It should be noted that custom HTTP methods are also handled in urllib.request.Request by setting the appropriate method attribute. Here is an example session that uses the PUT method:

>>> # This creates an HTTP request
>>> # with the content of BODY as the enclosed representation
>>> # for the resource http://localhost:8080/file
...
>>> import http.client
>>> BODY = "***filecontents***"
>>> conn = http.client.HTTPConnection("localhost", 8080)
>>> conn.request("PUT", "/file", BODY)
>>> response = conn.getresponse()
>>> print(response.status, response.reason)
200, OK

HTTPMessage 객체

class http.client.HTTPMessage(email.message.Message)

http.client.HTTPMessage 인스턴스는 HTTP 응답의 헤더를 보유합니다. email.message.Message 클래스를 사용하여 구현됩니다.

ftplib — FTP protocol client

소스 코드: Lib/ftplib.py [https://github.com/python/cpython/tree/main/Lib/ftplib.py]

This module defines the class FTP and a few related items. The FTP class implements the client side of the FTP protocol. You can use this to write Python programs that perform a variety of automated FTP jobs, such as mirroring other FTP servers. It is also used by the module urllib.request to handle URLs that use FTP. For more information on FTP (File Transfer Protocol), see internet RFC 959 [https://datatracker.ietf.org/doc/html/rfc959.html].

RFC 2640 [https://datatracker.ietf.org/doc/html/rfc2640.html]에 따라, 기본 인코딩은 UTF-8입니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

ftplib 모듈을 사용한 샘플 세션은 다음과 같습니다:

>>> from ftplib import FTP
>>> ftp = FTP('ftp.us.debian.org')  # connect to host, default port
>>> ftp.login()                     # user anonymous, passwd anonymous@
'230 Login successful.'
>>> ftp.cwd('debian')               # change into "debian" directory
'250 Directory successfully changed.'
>>> ftp.retrlines('LIST')           # list directory contents
-rw-rw-r--    1 1176     1176         1063 Jun 15 10:18 README
...
drwxr-sr-x    5 1176     1176         4096 Dec 19  2000 pool
drwxr-sr-x    4 1176     1176         4096 Nov 17  2008 project
drwxr-xr-x    3 1176     1176         4096 Oct 10  2012 tools
'226 Directory send OK.'
>>> with open('README', 'wb') as fp:
>>>     ftp.retrbinary('RETR README', fp.write)
'226 Transfer complete.'
>>> ftp.quit()
'221 Goodbye.'

Reference

FTP objects

class ftplib.FTP(host='', user='', passwd='', acct='', timeout=None, source_address=None, *, encoding='utf-8')

Return a new instance of the FTP class.

매개변수:

host (str) – The hostname to connect to. If given, connect(host) is implicitly called by the constructor.

user (str) – The username to log in with (default: 'anonymous'). If given, login(host, passwd, acct) is implicitly called by the constructor.

passwd (str) – The password to use when logging in. If not given, and if passwd is the empty string or "-", a password will be automatically generated.

acct (str) – Account information to be used for the ACCT FTP command. Few systems implement this. See RFC-959 [https://datatracker.ietf.org/doc/html/rfc959.html] for more details.

timeout (float | None) – A timeout in seconds for blocking operations like connect() (default: the global default timeout setting).

source_address (tuple | None) – A 2-tuple (host, port) for the socket to bind to as its source address before connecting.

encoding (str) – The encoding for directories and filenames (default: 'utf-8').

FTP 클래스는 with 문을 지원합니다, 예를 들어:

>>> from ftplib import FTP
>>> with FTP("ftp1.at.proftpd.org") as ftp:
...     ftp.login()
...     ftp.dir()
...
'230 Anonymous login ok, restrictions apply.'
dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 .
dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 ..
dr-xr-xr-x   5 ftp      ftp          4096 May  6 10:43 CentOS
dr-xr-xr-x   3 ftp      ftp            18 Jul 10  2008 Fedora
>>>

버전 3.2에서 변경: with 문에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: source_address 매개 변수가 추가되었습니다.

버전 3.9에서 변경: timeout 매개 변수가 0으로 설정되면, 비 블로킹 소켓이 만들어지지 않도록 ValueError를 발생시킵니다. encoding 매개 변수가 추가되었으며, 기본값은 Latin-1 에서 UTF-8로 변경되어 RFC 2640 [https://datatracker.ietf.org/doc/html/rfc2640.html]을 따릅니다.

Several FTP methods are available in two flavors: one for handling text files and another for binary files. The methods are named for the command which is used followed by lines for the text version or binary for the binary version.

FTP 인스턴스에는 다음과 같은 메서드가 있습니다:

set_debuglevel(level)

Set the instance’s debugging level as an int. This controls the amount of debugging output printed. The debug levels are:

0 (default): No debug output.

1: Produce a moderate amount of debug output, generally a single line per request.

2 or higher: Produce the maximum amount of debugging output, logging each line sent and received on the control connection.

connect(host='', port=0, timeout=None, source_address=None)

Connect to the given host and port. This function should be called only once for each instance; it should not be called if a host argument was given when the FTP instance was created. All other FTP methods can only be called after a connection has successfully been made.

매개변수:

host (str) – The host to connect to.

port (int) – The TCP port to connect to (default: 21, as specified by the FTP protocol specification). It is rarely needed to specify a different port number.

timeout (float | None) – A timeout in seconds for the connection attempt (default: the global default timeout setting).

source_address (tuple | None) – A 2-tuple (host, port) for the socket to bind to as its source address before connecting.

인자 self, host, port로 감사 이벤트 ftplib.connect를 발생시킵니다.

버전 3.3에서 변경: source_address 매개 변수가 추가되었습니다.

getwelcome()

초기 연결에 대한 응답으로 서버에서 보낸 환영 메시지를 반환합니다. (이 메시지에는 때때로 사용자와 관련될 수 있는 고지 사항이나 도움말 정보가 포함되어 있습니다.)

login(user='anonymous', passwd='', acct='')

Log on to the connected FTP server. This function should be called only once for each instance, after a connection has been established; it should not be called if the host and user arguments were given when the FTP instance was created. Most FTP commands are only allowed after the client has logged in.

매개변수:

user (str) – The username to log in with (default: 'anonymous').

passwd (str) – The password to use when logging in. If not given, and if passwd is the empty string or "-", a password will be automatically generated.

acct (str) – Account information to be used for the ACCT FTP command. Few systems implement this. See RFC-959 [https://datatracker.ietf.org/doc/html/rfc959.html] for more details.

abort()

진행 중인 파일 전송을 중단합니다. 이것을 사용하는 것이 항상 동작하지는 않지만, 시도해 볼 가치가 있습니다.

sendcmd(cmd)

간단한 명령 문자열을 서버로 보내고 응답 문자열을 반환합니다.

인자 self, cmd로 감사 이벤트 ftplib.sendcmd를 발생시킵니다.

voidcmd(cmd)

Send a simple command string to the server and handle the response. Return the response string if the response code corresponds to success (codes in the range 200–299). Raise error_reply otherwise.

인자 self, cmd로 감사 이벤트 ftplib.sendcmd를 발생시킵니다.

retrbinary(cmd, callback, blocksize=8192, rest=None)

Retrieve a file in binary transfer mode.

매개변수:

cmd (str) – An appropriate RETR command: "RETR filename".

callback (callable) – A single parameter callable that is called for each block of data received, with its single argument being the data as bytes.

blocksize (int) – The maximum chunk size to read on the low-level socket object created to do the actual transfer. This also corresponds to the largest size of data that will be passed to callback. Defaults to 8192.

rest (int) – A REST command to be sent to the server. See the documentation for the rest parameter of the transfercmd() method.

retrlines(cmd, callback=None)

Retrieve a file or directory listing in the encoding specified by the encoding parameter at initialization. cmd should be an appropriate RETR command (see retrbinary()) or a command such as LIST or NLST (usually just the string 'LIST'). LIST retrieves a list of files and information about those files. NLST retrieves a list of file names. The callback function is called for each line with a string argument containing the line with the trailing CRLF stripped. The default callback prints the line to sys.stdout.

set_pasv(val)

val이 참이면 “수동(passive)” 모드를 활성화하고, 그렇지 않으면 수동 모드를 비활성화합니다. 수동 모드는 기본적으로 켜져 있습니다.

storbinary(cmd, fp, blocksize=8192, callback=None, rest=None)

Store a file in binary transfer mode.

매개변수:

cmd (str) – An appropriate STOR command: "STOR filename".

fp (file object) – A file object (opened in binary mode) which is read until EOF, using its read() method in blocks of size blocksize to provide the data to be stored.

blocksize (int) – The read block size. Defaults to 8192.

callback (callable) – A single parameter callable that is called for each block of data sent, with its single argument being the data as bytes.

rest (int) – A REST command to be sent to the server. See the documentation for the rest parameter of the transfercmd() method.

버전 3.2에서 변경: The rest parameter was added.

storlines(cmd, fp, callback=None)

줄 모드로 파일을 저장합니다. cmd는 적절한 STOR 명령이어야 합니다 (storbinary()를 참조하십시오). 저장될 데이터를 제공하기 위해 readline() 메서드를 사용하여 (바이너리 모드로 열린) 파일 객체 fp에서 EOF까지 줄을 읽어 들입니다. callback은 줄마다 보내진 다음에 호출되는 선택적 단일 매개 변수 콜러블입니다.

transfercmd(cmd, rest=None)

데이터 연결을 통해 전송을 시작합니다. 전송이 활성화되면, EPRT나 PORT 명령과 cmd로 지정한 전송 명령을 보내고 연결을 받아들입니다. 서버가 수동(passive)이면, EPSV나 PASV 명령을 전송하고, 서버에 연결한 다음 전송 명령을 시작합니다. 어느 쪽이든, 연결 소켓을 반환합니다.

선택적 rest가 제공되면, REST 명령이 서버로 전송되고 rest를 인자로 전달합니다. rest는 일반적으로 요청된 파일에 대한 바이트 오프셋으로, 요청된 오프셋에서 파일 바이트 전송을 다시 시작하고 초기 바이트를 건너뛰도록 서버에 지시합니다. 그러나 transfercmd() 메서드는 초기화 때 지정된 encoding 매개 변수를 사용하여 rest를 문자열로 변환하지만, 문자열의 내용은 점검하지 않음에 유의하십시오. 서버가 REST 명령을 인식하지 못하면, error_reply 예외가 발생합니다. 이 경우, 단순히 rest 인자 없이 transfercmd()를 호출하십시오.

ntransfercmd(cmd, rest=None)

transfercmd()와 비슷하지만, 데이터 연결과 데이터의 예상 크기의 튜플을 반환합니다. 예상 크기를 계산할 수 없으면, None이 예상 크기로 반환됩니다. cmd와 rest는 transfercmd()에서와 같은 의미입니다.

mlsd(path='', facts=[])

MLSD 명령(RFC 3659 [https://datatracker.ietf.org/doc/html/rfc3659.html])을 사용하여 표준화된 형식으로 디렉터리를 나열합니다. path가 생략되면 현재 디렉터리를 가정합니다. facts는 원하는 정보 유형을 나타내는 문자열의 리스트입니다 (예를 들어 ["type", "size", "perm"]). 경로에서 발견된 모든 파일에 대해 두 요소의 튜플을 산출하는 제너레이터 객체를 반환합니다. 첫 번째 요소는 파일 이름이고, 두 번째 요소는 파일 이름에 대한 사실(facts)을 포함하는 딕셔너리입니다. 이 딕셔너리의 내용은 facts 인자에 의해 제한될 수 있지만, 서버가 요청된 모든 사실을 반환한다고 보장하지는 않습니다.

Added in version 3.3.

nlst(argument[, ...])

NLST 명령이 반환한 파일 이름 리스트를 반환합니다. 선택적 argument는 나열할 디렉터리입니다 (기본값은 현재 서버 디렉터리입니다). 비표준 옵션을 NLST 명령에 전달하기 위해 여러 인자를 사용할 수 있습니다.

참고

서버가 명령을 지원한다면, mlsd()가 더 나은 API를 제공합니다.

dir(argument[, ...])

Produce a directory listing as returned by the LIST command, printing it to standard output. The optional argument is a directory to list (default is the current server directory). Multiple arguments can be used to pass non-standard options to the LIST command. If the last argument is a function, it is used as a callback function as for retrlines(); the default prints to sys.stdout. This method returns None.

참고

서버가 명령을 지원한다면, mlsd()가 더 나은 API를 제공합니다.

rename(fromname, toname)

서버의 파일 fromname을 toname으로 이름을 바꿉니다.

delete(filename)

서버에서 filename이라는 파일을 제거합니다. 성공하면, 응답 텍스트를 반환하고, 그렇지 않으면 권한 에러면 error_perm을, 다른 에러면 error_reply를 발생시킵니다.

cwd(pathname)

서버에서 현재 디렉터리를 설정합니다.

mkd(pathname)

서버에서 새 디렉터리를 만듭니다.

pwd()

서버에서 현재 디렉터리의 경로명을 반환합니다.

rmd(dirname)

서버에서 dirname이라는 디렉터리를 제거합니다.

size(filename)

서버에서 filename이라는 파일의 크기를 요청합니다. 성공하면, 파일 크기가 정수로 반환되고, 그렇지 않으면 None이 반환됩니다. SIZE 명령은 표준화되어 있지 않지만, 많은 일반적인 서버 구현에서 지원됨에 유의하십시오.

quit()

QUIT 명령을 서버로 보내고 연결을 닫습니다. 이는 연결을 닫는 “정중한” 방법이지만, 서버가 QUIT 명령에 대해 에러로 응답하면 예외가 발생할 수 있습니다. 이것은 묵시적인 close() 메서드 호출을 수반하며, 이는 후속 호출에 FTP 인스턴스를 쓸모없게 만듭니다 (아래를 참조하십시오).

close()

일방적으로 연결을 닫습니다. 이것은 이미 닫힌 연결에는 적용되지 않아야 합니다, 가령 quit()를 성공적으로 호출한 후에. 이 호출 후 FTP 인스턴스를 더는 사용하지 않아야 합니다 (close()나 quit() 호출 후 다른 login() 메서드를 사용해서 연결을 다시 열 수 없습니다).

FTP_TLS objects

class ftplib.FTP_TLS(host='', user='', passwd='', acct='', *, context=None, timeout=None, source_address=None, encoding='utf-8')

An FTP subclass which adds TLS support to FTP as described in RFC 4217 [https://datatracker.ietf.org/doc/html/rfc4217.html]. Connect to port 21 implicitly securing the FTP control connection before authenticating.

참고

The user must explicitly secure the data connection by calling the prot_p() method.

매개변수:

host (str) – The hostname to connect to. If given, connect(host) is implicitly called by the constructor.

user (str) – The username to log in with (default: 'anonymous'). If given, login(host, passwd, acct) is implicitly called by the constructor.

passwd (str) – The password to use when logging in. If not given, and if passwd is the empty string or "-", a password will be automatically generated.

acct (str) – Account information to be used for the ACCT FTP command. Few systems implement this. See RFC-959 [https://datatracker.ietf.org/doc/html/rfc959.html] for more details.

context (ssl.SSLContext) – An SSL context object which allows bundling SSL configuration options, certificates and private keys into a single, potentially long-lived, structure. Please read 보안 고려 사항 for best practices.

timeout (float | None) – A timeout in seconds for blocking operations like connect() (default: the global default timeout setting).

source_address (tuple | None) – A 2-tuple (host, port) for the socket to bind to as its source address before connecting.

encoding (str) – The encoding for directories and filenames (default: 'utf-8').

Added in version 3.2.

버전 3.3에서 변경: Added the source_address parameter.

버전 3.4에서 변경: The class now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

버전 3.9에서 변경: timeout 매개 변수가 0으로 설정되면, 비 블로킹 소켓이 만들어지지 않도록 ValueError를 발생시킵니다. encoding 매개 변수가 추가되었으며, 기본값은 Latin-1 에서 UTF-8로 변경되어 RFC 2640 [https://datatracker.ietf.org/doc/html/rfc2640.html]을 따릅니다.

버전 3.12에서 변경: The deprecated keyfile and certfile parameters have been removed.

FTP_TLS 클래스를 사용한 샘플 세션은 다음과 같습니다:

>>> ftps = FTP_TLS('ftp.pureftpd.org')
>>> ftps.login()
'230 Anonymous user logged in'
>>> ftps.prot_p()
'200 Data protection level set to "private"'
>>> ftps.nlst()
['6jack', 'OpenBSD', 'antilink', 'blogbench', 'bsdcam', 'clockspeed', 'djbdns-jedi', 'docs', 'eaccelerator-jedi', 'favicon.ico', 'francotone', 'fugu', 'ignore', 'libpuzzle', 'metalog', 'minidentd', 'misc', 'mysql-udf-global-user-variables', 'php-jenkins-hash', 'php-skein-hash', 'php-webdav', 'phpaudit', 'phpbench', 'pincaster', 'ping', 'posto', 'pub', 'public', 'public_keys', 'pure-ftpd', 'qscan', 'qtc', 'sharedance', 'skycache', 'sound', 'tmp', 'ucarp']

FTP_TLS class inherits from FTP, defining these additional methods and attributes:

ssl_version

The SSL version to use (defaults to ssl.PROTOCOL_SSLv23).

auth()

ssl_version 어트리뷰트에 지정된 내용에 따라, TLS나 SSL을 사용하여 보안 제어 연결을 설정합니다.

버전 3.4에서 변경: The method now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

ccc()

제어 채널을 일반 텍스트로 되돌립니다. 고정 포트를 열지 않고 비보안 FTP로 NAT을 다루는 방법을 알고 있는 방화벽을 활용하는 데 유용할 수 있습니다.

Added in version 3.3.

prot_p()

보안 데이터 연결을 설정합니다.

prot_c()

일반 텍스트 데이터 연결을 설정합니다.

Module variables

exception ftplib.error_reply

서버에서 예기치 않은 응답이 수신될 때 발생하는 예외.

exception ftplib.error_temp

일시적 에러(400–499 범위의 응답 코드)를 나타내는 에러 코드가 수신될 때 발생하는 예외.

exception ftplib.error_perm

영구 에러(500–599 범위의 응답 코드)를 나타내는 에러 코드가 수신될 때 발생하는 예외.

exception ftplib.error_proto

서버로부터 FTP(File Transfer Protocol)의 응답 규격(즉, 1–5 범위의 숫자로 시작)에 맞지 않는 응답을 수신할 때 발생하는 예외.

ftplib.all_errors

FTP 인스턴스의 메서드가 (호출자로 인한 프로그래밍 에러가 아니라) FTP 연결 문제로 인해 발생시킬 수 있는 모든 예외의 집합 (튜플). 이 집합에는 위에 나열된 네 가지 예외뿐만 아니라 OSError와 EOFError가 포함됩니다.

더 보기

모듈 netrc

.netrc 파일 형식의 구문 분석기. .netrc 파일은 일반적으로 FTP 클라이언트가 사용자에게 프롬프트 하기 전에 사용자 인증 정보를 로드하는 데 사용됩니다.

poplib — POP3 protocol client

소스 코드: Lib/poplib.py [https://github.com/python/cpython/tree/main/Lib/poplib.py]

이 모듈은 POP3 서버에 대한 연결을 캡슐화하고 RFC 1939 [https://datatracker.ietf.org/doc/html/rfc1939.html]에 정의된 대로 프로토콜을 구현하는 클래스 POP3를 정의합니다. POP3 클래스는 RFC 1939 [https://datatracker.ietf.org/doc/html/rfc1939.html]의 최소(minimal)와 선택적인(optional) 명령 집합을 모두 지원합니다. POP3 클래스는 이미 맺어진 연결에서 암호화된 통신을 활성화하기 위해 RFC 2595 [https://datatracker.ietf.org/doc/html/rfc2595.html]에서 도입된 STLS 명령도 지원합니다.

또한, 이 모듈은 SSL을 하부 프로토콜 계층으로 사용하는 POP3 서버에 연결하기 위한 지원을 제공하는 클래스 POP3_SSL을 제공합니다.

POP3는 광범위하게 지원되지만 노후화되었음에 유의하십시오. POP3 서버의 구현 품질은 매우 다양하며, 그중 너무 많은 것들이 형편없습니다. 여러분의 메일 서버가 IMAP을 지원한다면, IMAP 서버가 더 잘 구현되는 경향이 있으므로 imaplib.IMAP4 클래스를 사용하는 것이 좋습니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

poplib 모듈은 두 가지 클래스를 제공합니다:

class poplib.POP3(host, port=POP3_PORT[, timeout])

이 클래스는 실제 POP3 프로토콜을 구현합니다. 인스턴스가 초기화될 때 연결이 만들어집니다. port를 생략하면, 표준 POP3 포트(110)가 사용됩니다. 선택적 timeout 매개 변수는 연결 시도의 제한 시간을 초로 지정합니다 (지정하지 않으면, 전역 기본 제한 시간 설정이 사용됩니다).

self, host, port를 인자로 감사 이벤트(auditing event) poplib.connect를 발생시킵니다.

모든 명령은 self와 line을 인자로 감사 이벤트(auditing event) poplib.putline을 발생시킵니다. 여기서 line은 원격 호스트로 보낼 바이트열입니다.

버전 3.9에서 변경: timeout 매개 변수가 0으로 설정되면, 비 블로킹 소켓이 만들어지지 않도록 ValueError를 발생시킵니다.

class poplib.POP3_SSL(host, port=POP3_SSL_PORT, *, timeout=None, context=None)

SSL 암호화된 소켓을 통해 서버에 연결하는 POP3의 서브 클래스입니다. port가 지정되지 않으면, 표준 POP3-over-SSL 포트(995)가 사용됩니다. timeout은 POP3 생성자에서처럼 동작합니다. context는 선택적인 ssl.SSLContext 객체인데, SSL 구성 옵션, 인증서 및 개인 키를 단일 (잠재적으로 수명이 긴) 구조로 묶을 수 있도록 합니다. 모범 사례는 보안 고려 사항을 읽으십시오.

self, host, port를 인자로 감사 이벤트(auditing event) poplib.connect를 발생시킵니다.

모든 명령은 self와 line을 인자로 감사 이벤트(auditing event) poplib.putline을 발생시킵니다. 여기서 line은 원격 호스트로 보낼 바이트열입니다.

버전 3.2에서 변경: context 매개 변수가 추가되었습니다.

버전 3.4에서 변경: The class now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

버전 3.9에서 변경: timeout 매개 변수가 0으로 설정되면, 비 블로킹 소켓이 만들어지지 않도록 ValueError를 발생시킵니다.

버전 3.12에서 변경: The deprecated keyfile and certfile parameters have been removed.

한가지 예외가 poplib 모듈의 어트리뷰트로 정의됩니다:

exception poplib.error_proto

이 모듈로부터 비롯된 모든 에러에서 발생하는 예외 (socket 모듈에서 비롯된 에러는 잡지 않습니다). 예외의 이유는 문자열로 생성자에 전달됩니다.

더 보기

모듈 imaplib

표준 파이썬 IMAP 모듈.

Frequently Asked Questions About Fetchmail [http://www.catb.org/~esr/fetchmail/fetchmail-FAQ.html]

fetchmail POP/IMAP 클라이언트에 대한 FAQ는 POP 프로토콜에 기반하는 응용 프로그램을 작성해야 할 때 유용할 수 있는 POP3 서버 다양성과 RFC 위반에 대한 정보를 수집합니다.

POP3 객체

All POP3 commands are represented by methods of the same name, in lowercase; most return the response text sent by the server.

A POP3 instance has the following methods:

POP3.set_debuglevel(level)

인스턴스의 디버깅 수준을 설정합니다. 이것은 인쇄되는 디버깅 출력의 양을 제어합니다. 기본값인 0은 디버깅 출력을 생성하지 않습니다. 1 값은 적절한 양의 디버깅 출력을 생성하는데, 일반적으로 요청당 한 줄입니다. 2 이상의 값은 제어 연결에서 보내고 받은 각 줄을 로깅 하여 최대량의 디버깅 출력을 생성합니다.

POP3.getwelcome()

POP3 서버가 보낸 인사말 문자열을 반환합니다.

POP3.capa()

RFC 2449 [https://datatracker.ietf.org/doc/html/rfc2449.html]에 지정된 대로 서버의 기능을 조회합니다. {'name': ['param'...]} 형식의 딕셔너리를 반환합니다.

Added in version 3.4.

POP3.user(username)

user 명령을 보냅니다, 응답은 암호가 필요함을 가리켜야 합니다.

POP3.pass_(password)

Send password, response includes message count and mailbox size. Note: the mailbox on the server is locked until quit() is called.

POP3.apop(user, secret)

POP3 서버에 로그인하기 위해 더 안전한 APOP 인증을 사용합니다.

POP3.rpop(user)

POP3 서버에 로그인하기 위해 RPOP 인증(유닉스 r-명령과 유사합니다)을 사용합니다.

POP3.stat()

우편함 상태를 가져옵니다. 결과는 2개의 정수의 튜플입니다: (message count, mailbox size).

POP3.list([which])

메시지 목록을 요청합니다, 결과는 (response, ['mesg_num octets', ...], octets) 형식입니다. which가 설정되면, 목록에 표시할 메시지입니다.

POP3.retr(which)

전체 메시지 번호 which를 가져오고 읽었음을 알리는 플래그를 설정합니다. 결과는 (response, ['line', ...], octets) 형식입니다.

POP3.dele(which)

메시지 번호 which를 삭제로 표시합니다. 대부분 서버에서 삭제는 실제로 QUIT 때까지 수행되지 않습니다 (주된 예외는 Eudora QPOP인데, 모든 연결 단절 시 계류 중인 삭제를 수행하여 의도적으로 RFC를 위반합니다).

POP3.rset()

우편함에 대한 모든 삭제 표시를 제거합니다.

POP3.noop()

아무것도 하지 않습니다. 연결 유지로 사용될 수 있습니다.

POP3.quit()

로그아웃: 변경 내용 커밋, 우편함 잠금 해제, 연결 끊기.

POP3.top(which, howmuch)

메시지 번호 which의 메시지 헤더와 메시지의 howmuch 개 줄을 가져옵니다. 결과는 (response, ['line', ...], octets) 형식입니다.

이 메서드가 사용하는 POP3 TOP 명령은, RETR 명령과 달리, 메시지의 읽었음을 알리는 플래그를 설정하지 않습니다; 불행히도, TOP은 RFC에서 부실하게 기술되어 있고 종종 유명하지 않은 서버에서 망가져 있습니다. 사용할 POP3 서버를 신뢰하기 전에 이 메서드를 수동으로 테스트하십시오.

POP3.uidl(which=None)

메시지 다이제스트 (고유 ID) 목록을 반환합니다. which가 지정되면, 결과에는 해당 메시지의 고유 ID가 'response mesgnum uid 형식으로 포함됩니다. 그렇지 않으면, 결과는 목록 (response, ['mesgnum uid', ...], octets)입니다.

POP3.utf8()

UTF-8 모드로의 전환을 시도합니다. 성공하면 서버 응답을 반환하고, 그렇지 않으면 error_proto를 발생시킵니다. RFC 6856 [https://datatracker.ietf.org/doc/html/rfc6856.html]에서 정의되었습니다.

Added in version 3.5.

POP3.stls(context=None)

RFC 2595 [https://datatracker.ietf.org/doc/html/rfc2595.html]에 지정된 대로 활성 연결에서 TLS 세션을 시작합니다. 사용자 인증 전에만 허용됩니다.

context 매개 변수는 ssl.SSLContext 객체인데, SSL 구성 옵션, 인증서 및 개인 키를 단일 (잠재적으로 수명이 긴) 구조로 묶을 수 있도록 합니다. 모범 사례는 보안 고려 사항을 읽으십시오.

This method supports hostname checking via ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

Added in version 3.4.

POP3_SSL의 인스턴스에는 추가 메서드가 없습니다. 이 서브 클래스의 인터페이스는 그 부모와 같습니다.

POP3 예제

다음은 우편함을 열고 모든 메시지를 가져와서 인쇄하는 (에러 검사 없는) 최소한의 예입니다:

import getpass, poplib

M = poplib.POP3('localhost')
M.user(getpass.getuser())
M.pass_(getpass.getpass())
numMessages = len(M.list()[1])
for i in range(numMessages):
    for j in M.retr(i+1)[1]:
        print(j)

모듈의 끝에는, 더욱 광범위한 사용 예제가 포함된 테스트 섹션이 있습니다.

imaplib — IMAP4 protocol client

소스 코드: Lib/imaplib.py [https://github.com/python/cpython/tree/main/Lib/imaplib.py]

이 모듈은 IMAP4, IMAP4_SSL 및 IMAP4_stream의 세 가지 클래스를 정의합니다. 이 클래스는 IMAP4 서버에 대한 연결을 캡슐화하고 RFC 2060 [https://datatracker.ietf.org/doc/html/rfc2060.html]에 정의된 대로 IMAP4rev1 클라이언트 프로토콜의 큰 부분 집합을 구현합니다. IMAP4 (RFC 1730 [https://datatracker.ietf.org/doc/html/rfc1730.html]) 서버와 하위 호환되지만, IMAP4에서는 STATUS 명령이 지원되지 않음에 유의하십시오.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

imaplib 모듈은 세 가지 클래스를 제공하며, IMAP4는 베이스 클래스입니다:

class imaplib.IMAP4(host='', port=IMAP4_PORT, timeout=None)

This class implements the actual IMAP4 protocol. The connection is created and protocol version (IMAP4 or IMAP4rev1) is determined when the instance is initialized. If host is not specified, '' (the local host) is used. If port is omitted, the standard IMAP4 port (143) is used. The optional timeout parameter specifies a timeout in seconds for the connection attempt. If timeout is not given or is None, the global default socket timeout is used.

IMAP4 클래스는 with 문을 지원합니다. 이처럼 사용될 때, with 문을 빠져나갈 때 IMAP4 LOGOUT 명령이 자동으로 발행됩니다. 예를 들어:

>>> from imaplib import IMAP4
>>> with IMAP4("domain.org") as M:
...     M.noop()
...
('OK', [b'Nothing Accomplished. d25if65hy903weo.87'])

버전 3.5에서 변경: with 문에 대한 지원이 추가되었습니다.

버전 3.9에서 변경: 선택적 timeout 매개 변수가 추가되었습니다.

세 가지 예외가 IMAP4 클래스의 어트리뷰트로 정의됩니다:

exception IMAP4.error

모든 에러에 대해 발생하는 예외. 예외의 이유는 문자열로 생성자에 전달됩니다.

exception IMAP4.abort

IMAP4 서버 에러는 이 예외를 발생시킵니다. 이것은 IMAP4.error의 서브 클래스입니다. 인스턴스를 닫고 새 인스턴스를 만들면 일반적으로 이 예외에서 복구할 수 있습니다.

exception IMAP4.readonly

쓰기 가능한 사서함(mailbox)의 상태가 서버에 의해 변경되면 이 예외가 발생합니다. 이것은 IMAP4.error의 서브 클래스입니다. 이제 일부 다른 클라이언트에는 쓰기 권한이 있으며, 쓰기 권한을 다시 얻으려면 사서함을 다시 열어야 합니다.

보안 연결을 위한 서브 클래스도 있습니다:

class imaplib.IMAP4_SSL(host='', port=IMAP4_SSL_PORT, *, ssl_context=None, timeout=None)

SSL 암호화 소켓을 통해 연결되는 IMAP4에서 파생된 서브 클래스입니다 (이 클래스를 사용하려면 SSL 지원과 함께 컴파일된 소켓 모듈이 필요합니다). host를 지정하지 않으면, ''(로컬 호스트)가 사용됩니다. port를 생략하면, 표준 IMAP4-over-SSL 포트(993)가 사용됩니다. ssl_context는 SSL 구성 옵션, 인증서 및 개인 키를 단일 (잠재적으로 오래가는) 구조로 번들링 할 수 있는 ssl.SSLContext 객체입니다. 모범 사례는 보안 고려 사항을 읽으십시오.

The optional timeout parameter specifies a timeout in seconds for the connection attempt. If timeout is not given or is None, the global default socket timeout is used.

버전 3.3에서 변경: ssl_context 매개 변수가 추가되었습니다.

버전 3.4에서 변경: The class now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

버전 3.9에서 변경: 선택적 timeout 매개 변수가 추가되었습니다.

버전 3.12에서 변경: The deprecated keyfile and certfile parameters have been removed.

두 번째 서브 클래스는 자식 프로세스가 만든 연결을 허용합니다:

class imaplib.IMAP4_stream(command)

이것은 command를 subprocess.Popen()에 전달하여 만들어진 stdin/stdout 파일 기술자에 연결하는 IMAP4에서 파생된 서브 클래스입니다.

다음과 같은 유틸리티 함수가 정의됩니다:

imaplib.Internaldate2tuple(datestr)

IMAP4 INTERNALDATE 문자열을 구문 분석하고 해당 지역 시간을 반환합니다. 반환 값은 time.struct_time 튜플이거나 문자열의 형식이 잘못되면 None입니다.

imaplib.Int2AP(num)

집합 [A .. P]의 문자를 사용하여 정수를 바이트열 표현으로 변환합니다.

imaplib.ParseFlags(flagstr)

IMAP4 FLAGS 응답을 개별 플래그의 튜플로 변환합니다.

imaplib.Time2Internaldate(date_time)

date_time을 IMAP4 INTERNALDATE 표현으로 변환합니다. 반환 값은 다음과 같은 형식의 문자열입니다: "DD-Mmm-YYYY HH:MM:SS +HHMM" (큰따옴표를 포함합니다). date_time 인자는 에포크 이후의 초(time.time()이 반환하는 것과 같습니다)를 나타내는 숫자 (int 또는 float), 지역 시간을 나타내는 9-튜플인 time.struct_time의 인스턴스 (time.localtime()이 반환하는 것과 같습니다), datetime.datetime의 어웨어(aware) 인스턴스 또는 큰따옴표로 인용된(double-quoted) 문자열일 수 있습니다. 마지막 경우에는, 이미 올바른 형식으로 되어 있다고 가정합니다.

사서함이 변경됨에 따라 IMAP4 메시지 번호가 변경됨에 유의하십시오. 특히, EXPUNGE 명령이 삭제를 수행한 후 나머지 메시지의 번호가 다시 매겨집니다. 따라서 UID 명령으로 UID를 대신 사용하는 것이 좋습니다.

모듈의 끝에는, 더 광범위한 사용 예제가 포함된 테스트 섹션이 있습니다.

더 보기

워싱턴 대학의 IMAP Information Center의 프로토콜을 설명하는 문서와 이를 구현하는 서버의 소스는 모두 (소스 코드) https://github.com/uw-imap/imap 에서 찾을 수 있습니다 (유지 보수되지 않습니다).

IMAP4 객체

All IMAP4rev1 commands are represented by methods of the same name, either uppercase or lowercase.

AUTHENTICATE와 IMAP4 리터럴로 전달되는 APPEND에 대한 마지막 인자를 제외하고, 명령에 대한 모든 인자는 문자열로 변환됩니다. 필요하면 (문자열에 IMAP4 프로토콜에 참여하는 문자가 포함되고 괄호나 큰따옴표로 묶이지 않았으면) 각 문자열이 인용됩니다. 그러나, LOGIN 명령에 대한 password 인자는 항상 인용됩니다. 인자 문자열이 인용되지 않도록 하려면 (예를 들어: STORE에 대한 flags 인자) 문자열을 괄호로 묶으십시오 (예를 들어: r'(\Deleted)').

각 명령은 튜플을 반환합니다: (type, [data, ...]) 여기서 type은 일반적으로 'OK'나 'NO'이며, data는 명령 응답의 텍스트이거나 명령의 위임된(mandated) 결과입니다. 각 data는 bytes이거나 튜플입니다. 튜플이면, 첫 번째 부분은 응답의 헤더이고, 두 번째 부분은 데이터를 포함합니다 (즉: ‘literal’ 값).

아래 명령에 대한 message_set 옵션은 수행할 하나 이상의 대상 메시지를 지정하는 문자열입니다. 단순 메시지 번호 ('1'), 메시지 번호 범위 ('2:4') 또는 쉼표로 구분된 불연속 범위 그룹('1:3,6:9')일 수 있습니다. 범위에는 별표가 포함되어 무한 상한을 나타낼 수 있습니다 ('3:*').

IMAP4 인스턴스에는 다음과 같은 메서드가 있습니다:

IMAP4.append(mailbox, flags, date_time, message)

명명된 사서함(mailbox)에 message를 추가합니다.

IMAP4.authenticate(mechanism, authobject)

인증 명령 — 응답 처리가 필요합니다.

mechanism은 사용할 인증 메커니즘을 지정합니다 - 인스턴스 변수 capabilities에 AUTH=mechanism 형식으로 나타나야 합니다.

authobject는 콜러블 객체여야 합니다:

data = authobject(response)

서버 계속(continuation) 응답을 처리하기 위해 호출됩니다; 전달된 response 인자는 bytes입니다. base64로 인코딩되어 서버로 전송되는 bytes data를 반환해야 합니다. 클라이언트 중단 응답 *를 대신 보내야 하면 None을 반환해야 합니다.

버전 3.5에서 변경: 문자열 사용자 이름과 비밀번호는 이제 ASCII로 제한되지 않고 utf-8로 인코딩됩니다.

IMAP4.check()

서버의 사서함을 검사합니다.

IMAP4.close()

현재 선택된 사서함을 닫습니다. 삭제된 메시지는 쓰기 가능한 사서함에서 제거됩니다. LOGOUT 이전의 권장 명령입니다.

IMAP4.copy(message_set, new_mailbox)

message_set 메시지를 new_mailbox 끝에 복사합니다.

IMAP4.create(mailbox)

mailbox라는 이름의 새 사서함을 만듭니다.

IMAP4.delete(mailbox)

mailbox라는 이름의 기존 사서함을 삭제합니다.

IMAP4.deleteacl(mailbox, who)

사서함(mailbox)의 사용자(who)에 대해 설정된 ACL을 삭제합니다 (모든 권한을 제거합니다).

IMAP4.enable(capability)

capability를 활성화합니다 (RFC 5161 [https://datatracker.ietf.org/doc/html/rfc5161.html]을 참조하십시오). 대부분의 기능은 활성화할 필요 없습니다. 현재 UTF8=ACCEPT 기능만 지원됩니다 (RFC 6855 [https://datatracker.ietf.org/doc/html/rfc6855.html]를 참조하십시오).

Added in version 3.5: enable() 메서드 자체와 RFC 6855 [https://datatracker.ietf.org/doc/html/rfc6855.html] 지원.

IMAP4.expunge()

선택한 사서함에서 삭제된 항목을 영구적으로 제거합니다. 삭제된 각 메시지에 대해 EXPUNGE 응답을 생성합니다. 반환된 데이터에는 수신된 순서의 EXPUNGE 메시지 번호 리스트가 포함됩니다.

IMAP4.fetch(message_set, message_parts)

메시지(일부)를 가져옵니다. message_parts는 괄호로 묶인 메시지 부분 이름의 문자열이어야 합니다, 예를 들어: "(UID BODY[TEXT])"). 반환된 데이터는 메시지 부분 봉투와 데이터의 튜플입니다.

IMAP4.getacl(mailbox)

mailbox에 대한 ACL을 가져옵니다. 이 메서드는 비표준이지만, Cyrus 서버에서 지원됩니다.

IMAP4.getannotation(mailbox, entry, attribute)

mailbox에 대해 지정된 ANNOTATION을 가져옵니다. 이 메서드는 비표준이지만, Cyrus 서버에서 지원됩니다.

IMAP4.getquota(root)

quota root의 자원 사용량과 제한을 가져옵니다. 이 메서드는 rfc2087에 정의된 IMAP4 QUOTA 확장의 일부입니다.

IMAP4.getquotaroot(mailbox)

명명된 mailbox에 대한 quota roots 리스트를 가져옵니다. 이 메서드는 rfc2087에 정의된 IMAP4 QUOTA 확장의 일부입니다.

IMAP4.list([directory[, pattern]])

directory에 있는 pattern과 일치하는 사서함 이름을 나열합니다. directory는 기본적으로 최상위 메일 폴더이며, pattern은 기본적으로 모든 것과 일치합니다. 반환된 데이터는 LIST의 리스트를 포함합니다.

IMAP4.login(user, password)

평문 비밀번호를 사용하여 클라이언트를 식별합니다. password는 인용됩니다.

IMAP4.login_cram_md5(user, password)

암호를 보호하기 위해 클라이언트를 식별할 때 CRAM-MD5 인증의 사용을 강제합니다. 서버 CAPABILITY 응답에 문구 AUTH=CRAM-MD5가 포함된 경우에만 작동합니다.

IMAP4.logout()

서버에 대한 연결을 종료합니다. 서버 BYE 응답을 반환합니다.

버전 3.8에서 변경: 이 메서드는 더는 임의의 예외를 조용히 무시하지 않습니다.

IMAP4.lsub(directory='""', pattern='*')

directory에 있는 pattern과 일치하는 구독한(subscribed) 사서함 이름을 나열합니다. directory는 기본적으로 최상위 디렉터리이고 pattern은 기본적으로 모든 사서함과 일치합니다. 반환된 데이터는 메시지 부분 봉투와 데이터의 튜플입니다.

IMAP4.myrights(mailbox)

mailbox에 대한 현재 사용자의 ACL(즉, 사서함에 대해 가진 권한)을 표시합니다.

IMAP4.namespace()

RFC 2342 [https://datatracker.ietf.org/doc/html/rfc2342.html]에 정의된 대로 IMAP 이름 공간을 반환합니다.

IMAP4.noop()

서버에 NOOP을 보냅니다.

IMAP4.open(host, port, timeout=None)

Opens socket to port at host. The optional timeout parameter specifies a timeout in seconds for the connection attempt. If timeout is not given or is None, the global default socket timeout is used. Also note that if the timeout parameter is set to be zero, it will raise a ValueError to reject creating a non-blocking socket. This method is implicitly called by the IMAP4 constructor. The connection objects established by this method will be used in the IMAP4.read(), IMAP4.readline(), IMAP4.send(), and IMAP4.shutdown() methods. You may override this method.

인자 self, host, port로 감사 이벤트 imaplib.open을 발생시킵니다.

버전 3.9에서 변경: timeout 매개 변수가 추가되었습니다.

IMAP4.partial(message_num, message_part, start, length)

메시지의 잘린 부분을 가져옵니다. 반환된 데이터는 메시지 부분 봉투와 데이터의 튜플입니다.

IMAP4.proxyauth(user)

인증을 user로 가정합니다. 권한 있는 관리자가 모든 사용자의 사서함으로 프락시 하도록 합니다.

IMAP4.read(size)

원격 서버에서 size 바이트를 읽습니다. 이 메서드를 재정의할 수 있습니다.

IMAP4.readline()

원격 서버에서 한 줄을 읽습니다. 이 메서드를 재정의할 수 있습니다.

IMAP4.recent()

업데이트를 서버에 요청합니다. 새 메시지가 없으면 반환된 데이터는 None이고, 그렇지 않으면 RECENT 응답의 값입니다.

IMAP4.rename(oldmailbox, newmailbox)

이름이 oldmailbox인 사서함의 이름을 newmailbox로 바꿉니다.

IMAP4.response(code)

수신되었다면 응답 code에 대한 데이터를 반환합니다, 또는 None을 반환합니다. 일반적인 유형 대신, 지정된 코드를 반환합니다.

IMAP4.search(charset, criterion[, ...])

일치하는 메시지가 있는지 사서함을 검색합니다. charset은 None일 수 있으며, 이 경우 서버에 대한 요청에 CHARSET이 지정되지 않습니다. IMAP 프로토콜은 적어도 하나의 기준을 지정하도록 요구합니다; 서버가 에러를 반환하면 예외가 발생합니다. enable() 명령을 사용하여 UTF8=ACCEPT 기능이 활성화되면 charset은 None이어야 합니다.

예:

# M is a connected IMAP4 instance...
typ, msgnums = M.search(None, 'FROM', '"LDJ"')

# or:
typ, msgnums = M.search(None, '(FROM "LDJ")')

IMAP4.select(mailbox='INBOX', readonly=False)

사서함을 선택합니다. 반환된 데이터는 mailbox에 있는 메시지 수입니다 (EXISTS 응답). 기본 mailbox는 'INBOX'입니다. readonly 플래그가 설정되면, 사서함을 수정할 수 없습니다.

IMAP4.send(data)

data를 원격 서버로 보냅니다. 이 메서드를 재정의할 수 있습니다.

인자 self, data로 감사 이벤트 imaplib.send를 발생시킵니다.

IMAP4.setacl(mailbox, who, what)

mailbox에 대한 ACL을 설정합니다. 이 메서드는 비표준이지만, Cyrus 서버에서 지원됩니다.

IMAP4.setannotation(mailbox, entry, attribute[, ...])

mailbox에 대한 ANNOTATION을 설정합니다. 이 메서드는 비표준이지만, Cyrus 서버에서 지원됩니다.

IMAP4.setquota(root, limits)

quota root의 자원 한도(limits)를 설정합니다. 이 메서드는 rfc2087에 정의된 IMAP4 QUOTA 확장의 일부입니다.

IMAP4.shutdown()

open에서 맺은 연결을 닫습니다. 이 메서드는 IMAP4.logout()에 의해 묵시적으로 호출됩니다. 이 메서드를 재정의할 수 있습니다.

IMAP4.socket()

서버에 연결하는 데 사용된 소켓 인스턴스를 반환합니다.

IMAP4.sort(sort_criteria, charset, search_criterion[, ...])

sort 명령은 결과에 대한 정렬이 추가된 search의 변형입니다. 반환된 데이터는 일치하는 메시지 번호의 공백으로 구분된 목록을 포함합니다.

sort에는 search_criterion 인자 앞에 두 개의 인자가 있습니다; sort_criteria의 괄호로 묶은 목록과 검색 charset. search와 달리, 검색 charset 인자는 필수임에 유의하십시오. uid search가 search에 해당하는 방식으로 sort에 해당하는 uid sort 명령도 있습니다. sort 명령은 먼저 검색 기준의 문자열 해석을 위해 charset 인자를 사용하여 주어진 검색 기준과 일치하는 메시지를 사서함에서 검색합니다. 그런 다음 일치하는 메시지 수를 반환합니다.

이것은 IMAP4rev1 확장 명령입니다.

IMAP4.starttls(ssl_context=None)

STARTTLS 명령을 보냅니다. ssl_context 인자는 선택적이며 ssl.SSLContext 객체여야 합니다. IMAP 연결의 암호화를 활성화합니다. 모범 사례는 보안 고려 사항을 읽으십시오.

Added in version 3.2.

버전 3.4에서 변경: The method now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

IMAP4.status(mailbox, names)

mailbox에 대한 명명된 상태 조건(status conditions)을 요청합니다.

IMAP4.store(message_set, command, flag_list)

사서함의 메시지에 대한 플래그 속성을 변경합니다. command는 RFC 2060 [https://datatracker.ietf.org/doc/html/rfc2060.html]의 섹션 6.4.6에서 “FLAGS”, “+ FLAGS” 또는 “-FLAGS” 중 하나로 지정되고, 선택적으로 “.SILENT” 접미사를 갖습니다.

예를 들어, 모든 메시지에 삭제 플래그를 설정하려면 다음을 수행합니다:

typ, data = M.search(None, 'ALL')
for num in data[0].split():
   M.store(num, '+FLAGS', '\\Deleted')
M.expunge()

참고

Creating flags containing ‘]’ (for example: “[test]”) violates RFC 3501 [https://datatracker.ietf.org/doc/html/rfc3501.html] (the IMAP protocol). However, imaplib has historically allowed creation of such tags, and popular IMAP servers, such as Gmail, accept and produce such flags. There are non-Python programs which also create such tags. Although it is an RFC violation and IMAP clients and servers are supposed to be strict, imaplib still continues to allow such tags to be created for backward compatibility reasons, and as of Python 3.6, handles them if they are sent from the server, since this improves real-world compatibility.

IMAP4.subscribe(mailbox)

새 사서함을 구독합니다.

IMAP4.thread(threading_algorithm, charset, search_criterion[, ...])

thread 명령은 결과에 대한 스레딩이 추가된 search의 변형입니다. 반환된 데이터는 스레드 구성원의 스페이스로 구분된 목록을 포함합니다.

스레드 구성원은 연속된 부모와 자식을 나타내는 스페이스로 구분된 0개 이상의 메시지 번호로 구성됩니다.

Thread has two arguments before the search_criterion argument(s); a threading_algorithm, and the searching charset. Note that unlike search, the searching charset argument is mandatory. There is also a uid thread command which corresponds to thread the way that uid search corresponds to search. The thread command first searches the mailbox for messages that match the given searching criteria using the charset argument for the interpretation of strings in the searching criteria. It then returns the matching messages threaded according to the specified threading algorithm.

이것은 IMAP4rev1 확장 명령입니다.

IMAP4.uid(command, arg[, ...])

메시지 번호가 아닌 UID로 식별된 메시지들로 명령 인자를 실행합니다. 명령에 적합한 응답을 반환합니다. 최소한 하나의 인자가 제공되어야 합니다; 아무것도 제공하지 않으면, 서버는 에러를 반환하고 예외가 발생합니다.

IMAP4.unsubscribe(mailbox)

기존 사서함에서 구독 취소합니다.

IMAP4.unselect()

imaplib.IMAP4.unselect()는 선택한 사서함과 관련된 서버 자원을 해제하고 서버를 인증된 상태로 되돌립니다. 이 명령은 현재 선택된 사서함에서 메시지가 영구적으로 제거되지 않는다는 점을 제외하고, imaplib.IMAP4.close()와 같은 작업을 수행합니다.

Added in version 3.9.

IMAP4.xatom(name[, ...])

CAPABILITY 응답에서 서버가 통지한 간단한 확장 명령을 허용합니다.

IMAP4 인스턴스에는 다음과 같은 어트리뷰트가 정의되어 있습니다:

IMAP4.PROTOCOL_VERSION

서버의 CAPABILITY 응답에서 가장 최근에 지원되는 프로토콜.

IMAP4.debug

디버깅 출력을 제어하기 위한 정숫값. 초기화 값은 모듈 변수 Debug에서 취합니다. 3보다 큰 값은 각 명령을 추적합니다.

IMAP4.utf8_enabled

일반적으로 False이지만, UTF8=ACCEPT 기능에 대해 enable() 명령이 성공적으로 발행되면 True로 설정되는 불리언 값.

Added in version 3.5.

IMAP4 예

다음은 사서함을 열고 모든 메시지를 가져오고 인쇄하는 최소한의 예(에러 검사는 없습니다)입니다:

import getpass, imaplib

M = imaplib.IMAP4(host='example.org')
M.login(getpass.getuser(), getpass.getpass())
M.select()
typ, data = M.search(None, 'ALL')
for num in data[0].split():
    typ, data = M.fetch(num, '(RFC822)')
    print('Message %s\n%s\n' % (num, data[0][1]))
M.close()
M.logout()

smtplib — SMTP protocol client

소스 코드: Lib/smtplib.py [https://github.com/python/cpython/tree/main/Lib/smtplib.py]

The smtplib module defines an SMTP client session object that can be used to send mail to any internet machine with an SMTP or ESMTP listener daemon. For details of SMTP and ESMTP operation, consult RFC 821 [https://datatracker.ietf.org/doc/html/rfc821.html] (Simple Mail Transfer Protocol) and RFC 1869 [https://datatracker.ietf.org/doc/html/rfc1869.html] (SMTP Service Extensions).

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

class smtplib.SMTP(host='', port=0, local_hostname=None, [timeout, ]source_address=None)

An SMTP instance encapsulates an SMTP connection. It has methods that support a full repertoire of SMTP and ESMTP operations. If the optional host and port parameters are given, the SMTP connect() method is called with those parameters during initialization. If specified, local_hostname is used as the FQDN of the local host in the HELO/EHLO command. Otherwise, the local hostname is found using socket.getfqdn(). If the connect() call returns anything other than a success code, an SMTPConnectError is raised. The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). If the timeout expires, TimeoutError is raised. The optional source_address parameter allows binding to some specific source address in a machine with multiple network interfaces, and/or to some specific source TCP port. It takes a 2-tuple (host, port), for the socket to bind to as its source address before connecting. If omitted (or if host or port are '' and/or 0 respectively) the OS default behavior will be used.

일반적인 사용을 위해서는, 초기화/연결, sendmail() 및 SMTP.quit() 메서드 만 필요합니다. 아래에 예가 포함되어 있습니다.

SMTP 클래스는 with 문을 지원합니다. 이처럼 사용되면, with 문이 종료될 때 SMTP QUIT 명령이 자동으로 발행됩니다. 예를 들어:

>>> from smtplib import SMTP
>>> with SMTP("domain.org") as smtp:
...     smtp.noop()
...
(250, b'Ok')
>>>

모든 명령은 인자 self와 data로 감사 이벤트 smtplib.SMTP.send를 발생시킵니다. 여기서 data는 원격 호스트로 전송될 바이트열입니다.

버전 3.3에서 변경: with 문에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: source_address argument was added.

Added in version 3.5: SMTPUTF8 확장(RFC 6531 [https://datatracker.ietf.org/doc/html/rfc6531.html])이 이제 지원됩니다.

버전 3.9에서 변경: If the timeout parameter is set to be zero, it will raise a ValueError to prevent the creation of a non-blocking socket.

class smtplib.SMTP_SSL(host='', port=0, local_hostname=None, *, [timeout, ]context=None, source_address=None)

SMTP_SSL 인스턴스는 SMTP 인스턴스와 정확히 같게 작동합니다. 연결 시작 시 SSL이 필요하고 starttls() 사용이 적합하지 않은 상황에서는 SMTP_SSL을 사용해야 합니다. host를 지정하지 않으면, 로컬 호스트가 사용됩니다. port가 0이면, 표준 SMTP-over-SSL 포트(465)가 사용됩니다. 선택적 인자 local_hostname, timeout 및 source_address는 SMTP 클래스에서와 같은 의미입니다. 역시 선택적인 context는 SSLContext를 포함할 수 있으며 보안 연결의 다양한 측면을 구성하도록 합니다. 모범 사례는 보안 고려 사항을 읽으십시오.

버전 3.3에서 변경: context가 추가되었습니다.

버전 3.3에서 변경: The source_address argument was added.

버전 3.4에서 변경: The class now supports hostname check with ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

버전 3.9에서 변경: timeout 매개 변수가 0으로 설정되면, 비 블로킹 소켓을 만드는 것을 막기 위해 ValueError가 발생합니다.

버전 3.12에서 변경: The deprecated keyfile and certfile parameters have been removed.

class smtplib.LMTP(host='', port=LMTP_PORT, local_hostname=None, source_address=None[, timeout])

The LMTP protocol, which is very similar to ESMTP, is heavily based on the standard SMTP client. It’s common to use Unix sockets for LMTP, so our connect() method must support that as well as a regular host:port server. The optional arguments local_hostname and source_address have the same meaning as they do in the SMTP class. To specify a Unix socket, you must use an absolute path for host, starting with a ‘/’.

일반 SMTP 메커니즘을 사용하여 인증이 지원됩니다. 유닉스 소켓을 사용할 때, LMTP는 일반적으로 인증을 지원하지 않거나 요구하지 않지만, 여러분의 상황에서는 다를 수 있습니다.

버전 3.9에서 변경: 선택적 timeout 매개 변수가 추가되었습니다.

훌륭한 예외 모음도 정의되어 있습니다:

exception smtplib.SMTPException

이 모듈에서 제공하는 다른 모든 예외에 대한 베이스 예외 클래스인 OSError의 서브 클래스.

버전 3.4에서 변경: SMTPException이 OSError의 서브 클래스가 되었습니다.

exception smtplib.SMTPServerDisconnected

이 예외는 예기치 않게 서버와의 연결이 끊어지거나, 서버에 연결하기 전에 SMTP 인스턴스를 사용하려고 할 때 발생합니다.

exception smtplib.SMTPResponseException

SMTP 에러 코드가 포함된 모든 예외의 베이스 클래스. 이러한 예외는 SMTP 서버가 에러 코드를 반환하는 일부 경우에 생성됩니다. 에러 코드는 에러의 smtp_code 어트리뷰트에 저장되며, smtp_error 어트리뷰트는 에러 메시지로 설정됩니다.

exception smtplib.SMTPSenderRefused

발신자 주소가 거부되었습니다. 모든 SMTPResponseException 예외에 의해 설정된 어트리뷰트 외에도, 이것은 ‘sender’를 SMTP 서버가 거부한 문자열로 설정합니다.

exception smtplib.SMTPRecipientsRefused

모든 수신자 주소가 거부되었습니다. 각 수신자의 에러는 SMTP.sendmail()이 반환하는 것과 정확히 같은 종류의 딕셔너리인 recipients 어트리뷰트를 통해 액세스 할 수 있습니다.

exception smtplib.SMTPDataError

SMTP 서버가 메시지 데이터 수락을 거부했습니다.

exception smtplib.SMTPConnectError

서버와의 연결을 설정하는 동안 에러가 발생했습니다.

exception smtplib.SMTPHeloError

서버가 HELO 메시지를 거부했습니다.

exception smtplib.SMTPNotSupportedError

시도한 명령이나 옵션이 서버에서 지원되지 않습니다.

Added in version 3.5.

exception smtplib.SMTPAuthenticationError

SMTP 인증이 잘못되었습니다. 서버가 제공된 username/password 조합을 수락하지 않았을 가능성이 높습니다.

더 보기

RFC 821 [https://datatracker.ietf.org/doc/html/rfc821.html] - Simple Mail Transfer Protocol

SMTP의 프로토콜 정의. 이 문서는 SMTP의 모델, 운영 절차 및 프로토콜 세부 사항을 다룹니다.

RFC 1869 [https://datatracker.ietf.org/doc/html/rfc1869.html] - SMTP Service Extensions

SMTP를 위한 ESMTP 확장의 정의. 이 문서는 새로운 명령으로 SMTP를 확장하고 서버에서 제공하는 명령의 동적 발견을 지원하는 프레임워크에 관해 설명하고, 몇 가지 추가 명령을 정의합니다.

SMTP 객체

SMTP 인스턴스에는 다음과 같은 메서드가 있습니다:

SMTP.set_debuglevel(level)

디버그 출력 수준을 설정합니다. level의 값이 1이나 True이면 연결과 서버와 주고받는 모든 메시지에 대한 디버그 메시지가 생성됩니다. level의 값이 2이면 이러한 메시지에 타임 스탬프가 추가됩니다.

버전 3.5에서 변경: 디버그 수준 2를 추가했습니다.

SMTP.docmd(cmd, args='')

서버에 cmd 명령을 전송합니다. 선택적 인자 args는 단순히 공백으로 구분하여 명령에 이어붙입니다.

숫자 응답 코드와 실제 응답 줄로 구성된 2-튜플을 반환합니다 (여러 줄 응답은 하나의 긴 줄로 결합합니다).

일반적인 작업에서 이 메서드를 명시적으로 호출할 필요는 없습니다. 다른 메서드를 구현하는 데 사용되며 개인적인 확장을 테스트하는 데 유용할 수 있습니다.

응답을 기다리는 동안 서버와의 연결이 끊어지면, SMTPServerDisconnected 가 발생합니다.

SMTP.connect(host='localhost', port=0)

지정된 포트(port)의 호스트(host)에 연결합니다. 기본값은 표준 SMTP 포트(25)로 로컬 호스트에 연결하는 것입니다. 호스트 이름이 콜론(':')으로 끝나고 그 뒤에 숫자가 오면 해당 접미사가 제거되고 숫자는 사용할 포트 번호로 해석됩니다. 이 메서드는 인스턴스 화 중에 호스트가 지정되면 생성자에 의해 자동으로 호출됩니다. 연결 응답에서 서버가 보낸 응답 코드와 메시지의 2-튜플을 반환합니다.

인자 self, host, port로 감사 이벤트 smtplib.connect를 발생시킵니다.

SMTP.helo(name='')

HELO 를 사용하여 SMTP 서버에 자신을 식별합니다. hostname 인자의 기본값은 로컬 호스트의 완전히 정규화된 도메인 이름(fully qualified domain name)입니다. 서버가 반환한 메시지는 객체의 helo_resp 어트리뷰트로 저장됩니다.

정상적인 작업에서는 이 메서드를 명시적으로 호출할 필요가 없습니다. 필요할 때 sendmail()에 의해 묵시적으로 호출됩니다.

SMTP.ehlo(name='')

Identify yourself to an ESMTP server using EHLO. The hostname argument defaults to the fully qualified domain name of the local host. Examine the response for ESMTP option and store them for use by has_extn(). Also sets several informational attributes: the message returned by the server is stored as the ehlo_resp attribute, does_esmtp is set to True or False depending on whether the server supports ESMTP, and esmtp_features will be a dictionary containing the names of the SMTP service extensions this server supports, and their parameters (if any).

메일을 보내기 전에 has_extn()을 사용하고 싶지 않은 한, 이 메서드를 명시적으로 호출할 필요는 없습니다. 필요할 때 sendmail()에 의해 묵시적으로 호출됩니다.

SMTP.ehlo_or_helo_if_needed()

이 세션에서 앞선 EHLO나 HELO 명령이 없으면, 이 메서드는 ehlo() 및/또는 helo()를 호출합니다. ESMTP EHLO를 먼저 시도합니다.

SMTPHeloError

서버가 HELO 인사에 올바르게 응답하지 않았습니다.

SMTP.has_extn(name)

name이 서버가 반환한 SMTP 서비스 확장 집합에 있으면 True를 반환하고, 그렇지 않으면 False를 반환합니다. 대소 문자는 무시됩니다.

SMTP.verify(address)

SMTP VRFY를 사용하여 이 서버에서 주소의 유효성을 확인합니다. 사용자 주소가 유효하면 코드 250과 전체 RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] 주소(사람 이름 포함)로 구성된 튜플을 반환합니다. 그렇지 않으면 400 이상의 SMTP 에러 코드와 에러 문자열을 반환합니다.

참고

많은 사이트에서 스패머를 제거하기 위해 SMTP VRFY를 비활성화합니다.

SMTP.login(user, password, *, initial_response_ok=True)

인증이 필요한 SMTP 서버에 로그인합니다. 인자는 인증할 사용자 이름과 비밀번호입니다. 이 세션에 앞선 EHLO나 HELO 명령이 없었으면, 이 메서드는 ESMTP EHLO를 먼저 시도합니다. 인증에 성공하면 이 메서드는 정상적으로 반환하고, 그렇지 않으면 다음 예외를 발생시킬 수 있습니다:

SMTPHeloError

서버가 HELO 인사에 올바르게 응답하지 않았습니다.

SMTPAuthenticationError

서버가 사용자 이름/비밀번호 조합을 수락하지 않았습니다.

SMTPNotSupportedError

서버가 AUTH 명령을 지원하지 않습니다.

SMTPException

적합한 인증 메서드가 없습니다.

smtplib가 지원하는 각 인증 메서드는 서버가 지원하는 것으로 광고되면 차례로 시도됩니다. 지원되는 인증 메서드 목록은 auth()를 참조하십시오. initial_response_ok는 auth()로 전달됩니다.

선택적 키워드 인자 initial_response_ok는, 이를 지원하는 인증 메서드의 경우, 챌린지/응답을 요구하지 않고 RFC 4954 [https://datatracker.ietf.org/doc/html/rfc4954.html]에 지정된 “초기 응답(initial response)”을 AUTH 명령과 함께 보낼 수 있는지를 지정합니다.

버전 3.5에서 변경: SMTPNotSupportedError 가 발생할 수 있고, initial_response_ok 매개 변수가 추가되었습니다.

SMTP.auth(mechanism, authobject, *, initial_response_ok=True)

지정된 인증 메커니즘(mechanism)으로 SMTP AUTH 명령을 발행하고, authobject를 통해 챌린지 응답을 처리합니다.

mechanism은 AUTH 명령의 인자로 사용할 인증 메커니즘을 지정합니다; 유효한 값은 esmtp_features의 auth 요소에 나열된 값입니다.

authobject must be a callable object taking an optional single argument:

data = authobject(challenge=None)

선택적 키워드 인자 initial_response_ok가 참이면, 인자 없이 authobject()가 먼저 호출됩니다. 이것은 RFC 4954 [https://datatracker.ietf.org/doc/html/rfc4954.html] “초기 응답(initial response)” ASCII str을 반환할 수 있으며, 이는 아래와 같이 AUTH 명령으로 인코딩되고 전송됩니다. authobject()가 초기 응답을 지원하지 않으면 (예를 들어 챌린지가 필요하기 때문에), challenge=None으로 호출될 때 None을 반환해야 합니다. initial_response_ok가 거짓이면, authobject()는 None으로 먼저 호출되지 않습니다.

초기 응답 확인이 None을 반환하거나, initial_response_ok가 거짓이면, 서버의 챌린지 응답을 처리하기 위해 authobject()가 호출됩니다; 전달된 challenge 인자는 bytes입니다. base64로 인코딩되어 서버로 전송될 ASCII str data를 반환해야 합니다.

SMTP 클래스는 CRAM-MD5, PLAIN 및 LOGIN 메커니즘을 위한 authobjects를 제공합니다. 그것들은 각각 SMTP.auth_cram_md5, SMTP.auth_plain 및 SMTP.auth_login으로 명명됩니다. 모두 SMTP 인스턴스의 user와 password 프로퍼티가 적절한 값으로 설정되어 있도록 요구합니다.

사용자 코드는 일반적으로 auth를 직접 호출할 필요는 없지만, 대신 login() 메서드를 호출할 수는 있는데, 위의 각 메커니즘을 나열된 순서대로 시도합니다. auth는 smtplib가 직접 지원하지 않는 (또는 아직 지원하지 않는) 인증 메서드를 쉽게 구현할 수 있도록 노출되어 있습니다.

Added in version 3.5.

SMTP.starttls(*, context=None)

SMTP 연결을 TLS (Transport Layer Security) 모드로 전환합니다. 뒤따르는 모든 SMTP 명령은 암호화됩니다. 그런 다음 ehlo()를 다시 호출해야 합니다.

keyfile과 certfile이 제공되면, ssl.SSLContext를 만드는 데 사용됩니다.

선택적 context 매개 변수는 ssl.SSLContext 객체입니다; 이것은 keyfile과 certfile대신 사용할 수 있으며 keyfile과 certfile이 모두 지정되면 None이어야 합니다.

이 세션에 앞선 EHLO나 HELO 명령이 없었으면, 이 메서드는 ESMTP EHLO를 먼저 시도합니다.

버전 3.12에서 변경: The deprecated keyfile and certfile parameters have been removed.

SMTPHeloError

서버가 HELO 인사에 올바르게 응답하지 않았습니다.

SMTPNotSupportedError

서버가 STARTTLS 확장을 지원하지 않습니다.

RuntimeError

파이썬 인터프리터가 SSL/TLS를 지원하지 않습니다.

버전 3.3에서 변경: context가 추가되었습니다.

버전 3.4에서 변경: The method now supports hostname check with SSLContext.check_hostname and Server Name Indicator (see HAS_SNI).

버전 3.5에서 변경: STARTTLS 지원 부족으로 발생한 에러는 이제 베이스 SMTPException 대신 SMTPNotSupportedError 서브 클래스입니다.

SMTP.sendmail(from_addr, to_addrs, msg, mail_options=(), rcpt_options=())

메일을 보냅니다. 필수 인자는 RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] from-address 문자열, RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] to-address 문자열의 리스트 (단순 문자열은 주소가 한 개인 리스트로 처리됩니다) 및 메시지 문자열입니다. 호출자는 MAIL FROM 명령에 사용되는 ESMTP 옵션 (가령 8bitmime) 리스트를 mail_options로 전달할 수 있습니다. 모든 RCPT 명령과 함께 사용해야 하는 ESMTP 옵션(가령 DSN 명령)을 rcpt_options로 전달할 수 있습니다. (다른 수신자에게 다른 ESMTP 옵션을 사용해야 하면 메시지를 보내는 데 mail(), rcpt() 및 data()와 같은 저수준 메서드를 사용해야 합니다.)

참고

from_addr과 to_addrs 매개 변수는 전송 에이전트가 사용하는 메시지 봉투(envelope)를 구성하는 데 사용됩니다. sendmail은 어떤 방식으로든 메시지 헤더를 수정하지 않습니다.

msg는 ASCII 범위의 문자를 포함하는 문자열이거나, 바이트 문자열일 수 있습니다. 문자열은 ascii 코덱을 사용하여 바이트열로 인코딩되며, 독립된 \r과 \n 문자는 \r\n 문자로 변환됩니다. 바이트 문자열은 수정되지 않습니다.

이 세션에 앞선 EHLO나 HELO 명령이 없었으면, 이 메서드는 ESMTP EHLO를 먼저 시도합니다. 서버가 ESMTP를 지원하면, 메시지 크기와 지정된 각 옵션이 전달됩니다 (옵션이 서버가 광고한 기능 집합에 있다면). EHLO가 실패하면, HELO가 시도되고 ESMTP 옵션이 억제됩니다.

이 메서드는 적어도 한 명의 수신자에게 메일이 수락되면 정상적으로 반환됩니다. 그렇지 않으면 예외가 발생합니다. 즉, 이 메서드로 예외가 발생하지 않으면 누군가 메일을 받아야 합니다. 이 메서드에서 예외가 발생하지 않으면, 거부된 각 수신자에 대해 하나의 항목이 있는 딕셔너리를 반환합니다. 각 항목에는 서버에서 보낸 SMTP 에러 코드와 해당 에러 메시지의 튜플이 포함됩니다.

SMTPUTF8이 mail_options에 포함되어 있고, 서버가 이를 지원하면, from_addr과 to_addrs는 ASCII가 아닌 문자를 포함할 수 있습니다.

이 메서드는 다음과 같은 예외를 발생시킬 수 있습니다:

SMTPRecipientsRefused

모든 수신자가 거부되었습니다. 아무도 메일을 받지 못했습니다. 예외 객체의 recipients 어트리뷰트는 거부된 수신자에 대한 정보가 있는 딕셔너리입니다 (적어도 한 명의 수신자가 수락되었을 때 반환되는 것과 같습니다).

SMTPHeloError

서버가 HELO 인사에 올바르게 응답하지 않았습니다.

SMTPSenderRefused

서버가 from_addr을 수락하지 않았습니다.

SMTPDataError

서버가 예기치 않은 에러 코드(수신자 거부는 제외하고)로 응답했습니다.

SMTPNotSupportedError

SMTPUTF8이 mail_options에 제공되었지만, 서버에서 지원되지 않습니다.

달리 명시되지 않는 한, 예외가 발생한 후에도 연결은 열려있습니다.

버전 3.2에서 변경: msg는 바이트 문자열일 수 있습니다.

버전 3.5에서 변경: SMTPUTF8 지원이 추가되었으며, SMTPUTF8이 지정되었지만, 서버가 지원하지 않으면 SMTPNotSupportedError 가 발생할 수 있습니다.

SMTP.send_message(msg, from_addr=None, to_addrs=None, mail_options=(), rcpt_options=())

이는 email.message.Message 객체로 표현되는 메시지로 sendmail()을 호출하는 편의 메서드입니다. 인자는 msg가 Message 객체라는 점을 제외하고 sendmail()과 같은 의미입니다.

from_addr이 None이거나 to_addrs가 None이면, send_message는 RFC 5322 [https://datatracker.ietf.org/doc/html/rfc5322.html] 에 지정된 대로 msg의 헤더에서 추출된 주소로 해당 인자를 채웁니다: from_addr은 Sender 필드가 있으면 이것으로 설정되고, 그렇지 않으면 From 필드로 설정됩니다. to_addrs는 (있다면) msg의 To, Cc 및 Bcc 필드 값을 결합합니다. 정확히 하나의 Resent-* 헤더 집합이 메시지에 등장하면, 일반 헤더는 무시되고 Resent-* 헤더가 대신 사용됩니다. 메시지에 둘 이상의 Resent-* 헤더 집합이 포함되면, 가장 최근의 Resent- 헤더 집합을 모호하지 않게 감지할 방법이 없어서 ValueError가 발생합니다.

send_message는 \r\n을 linesep으로 사용하여 BytesGenerator를 통해 msg를 직렬화하고, sendmail()을 호출하여 결과 메시지를 전송합니다. from_addr과 to_addrs의 값과 관계없이 send_message는 msg에 나타날 수 있는 Bcc나 Resent-Bcc 헤더를 전송하지 않습니다. from_addr과 to_addrs의 주소 중 하나에 ASCII가 아닌 문자가 포함되어 있고 서버가 SMTPUTF8 지원을 광고하지 않으면, SMTPNotSupported 에러가 발생합니다. 그렇지 않으면 Message는 utf8 어트리뷰트가 True로 설정된 자신의 policy의 복제본으로 직렬화되고, SMTPUTF8 과 BODY=8BITMIME이 mail_options에 추가됩니다.

Added in version 3.2.

Added in version 3.5: 국제화된 주소 (SMTPUTF8) 지원.

SMTP.quit()

SMTP 세션을 종료하고 연결을 닫습니다. SMTP QUIT 명령의 결과를 반환합니다.

표준 SMTP/ESMTP 명령 HELP, RSET, NOOP, MAIL, RCPT 및 DATA에 해당하는 저수준 메서드도 지원됩니다. 일반적으로 이들은 직접 호출할 필요가 없어서, 여기에 설명되어 있지 않습니다. 자세한 내용은, 모듈 코드를 참조하십시오.

SMTP 예

This example prompts the user for addresses needed in the message envelope (‘To’ and ‘From’ addresses), and the message to be delivered. Note that the headers to be included with the message must be included in the message as entered; this example doesn’t do any processing of the RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html] headers. In particular, the ‘To’ and ‘From’ addresses must be included in the message headers explicitly:

import smtplib

def prompt(title):
    return input(title).strip()

from_addr = prompt("From: ")
to_addrs  = prompt("To: ").split()
print("Enter message, end with ^D (Unix) or ^Z (Windows):")

# Add the From: and To: headers at the start!
lines = [f"From: {from_addr}", f"To: {', '.join(to_addrs)}", ""]
while True:
    try:
        line = input()
    except EOFError:
        break
    else:
        lines.append(line)

msg = "\r\n".join(lines)
print("Message length is", len(msg))

server = smtplib.SMTP("localhost")
server.set_debuglevel(1)
server.sendmail(from_addr, to_addrs, msg)
server.quit()

참고

일반적으로, email 패키지의 기능을 사용하여 전자 메일 메시지를 만들고자 할 것이고, 그런 다음 send_message()를 통해 보낼 수 있습니다; email: 예제를 참조하십시오.

uuid — UUID objects according to RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html]

소스 코드: Lib/uuid.py [https://github.com/python/cpython/tree/main/Lib/uuid.py]

This module provides immutable UUID objects (the UUID class) and the functions uuid1(), uuid3(), uuid4(), uuid5(), and uuid.uuid8() for generating version 1, 3, 4, 5, and 8 UUIDs as specified in RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html] (which supersedes RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html]).

고유 ID만을 얻고자 한다면 uuid1() 또는 uuid4()를 호출하는 것이 좋습니다. uuid1() 함수는 컴퓨터의 네트워크 주소를 포함하여 UUID를 생성하므로 개인정보가 노출될 수 있음을 명심해야 합니다. uuid4()는 무작위 UUID를 생성합니다.

Depending on support from the underlying platform, uuid1() may or may not return a “safe” UUID. A safe UUID is one which is generated using synchronization methods that ensure no two processes can obtain the same UUID. All instances of UUID have an is_safe attribute which relays any information about the UUID’s safety, using this enumeration:

class uuid.SafeUUID

Added in version 3.7.

safe

플랫폼이 다중 프로세스에 안전한 방식으로 UUID를 생성합니다.

unsafe

다중 프로세스에 안전한 방식으로 생성되지 않습니다.

unknown

플랫폼이 UUID를 안전하게 생성하였는지에 대한 정보를 제공하지 않습니다.

class uuid.UUID(hex=None, bytes=None, bytes_le=None, fields=None, int=None, version=None, *, is_safe=SafeUUID.unknown)

32자리 16진수 문자열, bytes 인자에 빅 엔디안 순서 16바이트열, bytes_le 인자에 리틀 엔디안 순서 16바이트열, fields 인자에 여섯 개의 정수로 이루어진 튜플(32-bit time_low, 16-bit time_mid, 16-bit time_hi_version, 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node), int 인자에 단일 128bit 정수 중 하나를 이용하여 UUID를 만듭니다. 16진수 문자열로 주어졌을 경우 중괄호, 붙임표(hyphen), URN 접두어는 모두 선택사항입니다. 예를 들어, 아래 표현들은 모두 같은 UUID를 산출합니다:

UUID('{12345678-1234-5678-1234-567812345678}')
UUID('12345678123456781234567812345678')
UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
UUID(bytes=b'\x12\x34\x56\x78'*4)
UUID(bytes_le=b'\x78\x56\x34\x12\x34\x12\x78\x56' +
              b'\x12\x34\x56\x78\x12\x34\x56\x78')
UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
UUID(int=0x12345678123456781234567812345678)

Exactly one of hex, bytes, bytes_le, fields, or int must be given. The version argument is optional; if given, the resulting UUID will have its variant and version number set according to RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html], overriding bits in the given hex, bytes, bytes_le, fields, or int.

UUID 객체끼리 비교할 때 UUID.int 어트리뷰트를 비교하여 수행합니다. UUID가 아닌 객체와 비교하면 TypeError가 발생합니다.

str(uuid)는 12345678-1234-5678-1234-567812345678과같이 32자리 16진수 UUID로 표현합니다.

UUID 객체는 다음과 같은 읽기 전용 어트리뷰트를 갖습니다.

UUID.bytes

16바이트 문자열(여섯 개의 빅 엔디안 순서 정수 필드 포함)인 UUID

UUID.bytes_le

16바이트 문자열(리틀 엔디안 순서 time_low, time_mid, time_hi_version)인 UUID

UUID.fields

UUID의 여섯 개의 정수 필드로 이루어진 튜플. 여섯 개의 개별 어트리뷰트와 두 개의 파생된 어트리뷰트도 사용 가능:

필드

의미

UUID.time_low

The first 32 bits of the UUID.

UUID.time_mid

The next 16 bits of the UUID.

UUID.time_hi_version

The next 16 bits of the UUID.

UUID.clock_seq_hi_variant

The next 8 bits of the UUID.

UUID.clock_seq_low

The next 8 bits of the UUID.

UUID.node

The last 48 bits of the UUID.

UUID.time

The 60-bit timestamp.

UUID.clock_seq

The 14-bit sequence number.

UUID.hex

The UUID as a 32-character lowercase hexadecimal string.

UUID.int

128bit 정수 UUID

UUID.urn

The UUID as a URN as specified in RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html].

UUID.variant

UUID 변종은 UUID의 내부 레이아웃을 결정합니다. 이는 상수 RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, 및 RESERVED_FUTURE 중 하나입니다.

UUID.version

The UUID version number (1 through 8, meaningful only when the variant is RFC_4122).

버전 3.14에서 변경: Added UUID version 8.

UUID.is_safe

플랫폼이 UUID를 다중 프로세스에 안전한 방식으로 생성했는지를 나타내는 SafeUUID의 열거체입니다.

Added in version 3.7.

uuid 모듈은 다음의 함수들을 정의합니다.

uuid.getnode()

하드웨어 주소를 48bit 양의 정수로 가져옵니다. 최초 실행 시 별도의 프로그램으로 실행될 수 있고, 매우 느려질 수 있습니다. 하드웨어 주소를 얻기 위한 시도가 모두 실패하면, RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html]가 권장하는 대로 멀티캐스트 비트(첫 옥텟의 최하위 비트)가 1로 설정된 무작위 48bit 숫자를 선택합니다. “하드웨어 주소”는 네트워크 인터페이스의 MAC 주소를 뜻합니다. 여러 네트워크 인터페이스를 가진 머신에서 보편적으로 관리하는 MAC 주소(즉, 첫 번째 옥텟의 두 번째 최하위 비트가 unset인 경우)는 로컬에서 관리하는 MAC 주소보다 우선하지만, 순서를 보장하지는 않습니다.

버전 3.7에서 변경: 보편적으로 관리하는 MAC 주소는 로컬로 관리하는 MAC 주소보다 우선합니다. 전자는 주소가 전 세계적으로 고유함을 보장하지만, 후자는 그렇지 않기 때문입니다.

uuid.uuid1(node=None, clock_seq=None)

호스트 ID, 시퀀스 번호 및 현재 시각으로 UUID 생성. node가 주어지지 않으면, getnode()를 사용하여 하드웨어 주소를 얻습니다. clock_seq가 주어지면 시퀀스 번호로 사용합니다. 그렇지 않을 경우, 무작위 14bit 시퀀스 번호를 사용합니다.

uuid.uuid3(namespace, name)

Generate a UUID based on the MD5 hash of a namespace identifier (which is a UUID) and a name (which is a bytes object or a string that will be encoded using UTF-8).

uuid.uuid4()

무작위 UUID 생성.

uuid.uuid5(namespace, name)

Generate a UUID based on the SHA-1 hash of a namespace identifier (which is a UUID) and a name (which is a bytes object or a string that will be encoded using UTF-8).

uuid.uuid8(a=None, b=None, c=None)

Generate a pseudo-random UUID according to RFC 9562, §5.8 [https://datatracker.ietf.org/doc/html/rfc9562.html#section-5.8].

When specified, the parameters a, b and c are expected to be positive integers of 48, 12 and 62 bits respectively. If they exceed their expected bit count, only their least significant bits are kept; non-specified arguments are substituted for a pseudo-random integer of appropriate size.

Added in version 3.14.

uuid 모듈은 uuid3()과 uuid5()를 위한 아래의 이름 공간 식별자를 정의합니다.

uuid.NAMESPACE_DNS

When this namespace is specified, the name string is a fully qualified domain name.

uuid.NAMESPACE_URL

이 이름 공간이 지정되면 name 문자열은 URL입니다.

uuid.NAMESPACE_OID

이 이름 공간이 지정되면 name 문자열은 ISO OID입니다.

uuid.NAMESPACE_X500

이 이름 공간이 지정되면 name 문자열은 DER이나 텍스트 출력 형식의 X.500 DN입니다.

The uuid module defines the following constants for the possible values of the variant attribute:

uuid.RESERVED_NCS

NCS 호환성을 위해 예약됨.

uuid.RFC_4122

Specifies the UUID layout given in RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html]. This constant is kept for backward compatibility even though RFC 4122 [https://datatracker.ietf.org/doc/html/rfc4122.html] has been superseded by RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html].

uuid.RESERVED_MICROSOFT

마이크로소프트 호환성을 위해 예약됨.

uuid.RESERVED_FUTURE

추후 정의를 위해 예약됨.

더 보기

RFC 9562 [https://datatracker.ietf.org/doc/html/rfc9562.html] - A Universally Unique IDentifier (UUID) URN Namespace

이 명세는 UUID를 위한 통합 자원 식별자 이름 공간, UUID의 내부 형식 및 UUID 생성 방법을 정의합니다.

Command-Line Usage

Added in version 3.12.

The uuid module can be executed as a script from the command line.

python -m uuid [-h] [-u {uuid1,uuid3,uuid4,uuid5,uuid8}] [-n NAMESPACE] [-N NAME]

The following options are accepted:

-h, --help

Show the help message and exit.

-u <uuid>

--uuid <uuid>

Specify the function name to use to generate the uuid. By default uuid4() is used.

Added in version 3.14: Allow generating UUID version 8.

-n <namespace>

--namespace <namespace>

The namespace is a UUID, or @ns where ns is a well-known predefined UUID addressed by namespace name. Such as @dns, @url, @oid, and @x500. Only required for uuid3() / uuid5() functions.

-N <name>

--name <name>

The name used as part of generating the uuid. Only required for uuid3() / uuid5() functions.

예제

uuid 모듈을 사용하는 전형적인 몇 가지 예제입니다:

>>> import uuid

>>> # make a UUID based on the host ID and current time
>>> uuid.uuid1()
UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')

>>> # make a UUID using an MD5 hash of a namespace UUID and a name
>>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')

>>> # make a random UUID
>>> uuid.uuid4()
UUID('16fd2706-8baf-433b-82eb-8c7fada847da')

>>> # make a UUID using a SHA-1 hash of a namespace UUID and a name
>>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')

>>> # make a UUID from a string of hex digits (braces and hyphens ignored)
>>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')

>>> # convert a UUID to a string of hex digits in standard form
>>> str(x)
'00010203-0405-0607-0809-0a0b0c0d0e0f'

>>> # get the raw 16 bytes of the UUID
>>> x.bytes
b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'

>>> # make a UUID from a 16-byte string
>>> uuid.UUID(bytes=x.bytes)
UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')

Command-Line Example

Here are some examples of typical usage of the uuid command line interface:

# generate a random uuid - by default uuid4() is used
$ python -m uuid

# generate a uuid using uuid1()
$ python -m uuid -u uuid1

# generate a uuid using uuid5
$ python -m uuid -u uuid5 -n @url -N example.com

socketserver — A framework for network servers

소스 코드: Lib/socketserver.py [https://github.com/python/cpython/tree/main/Lib/socketserver.py]

socketserver 모듈은 네트워크 서버 작성 작업을 단순화합니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

다음과 같은 네 가지 기본 구상 서버 클래스가 있습니다:

class socketserver.TCPServer(server_address, RequestHandlerClass, bind_and_activate=True)

This uses the internet TCP protocol, which provides for continuous streams of data between the client and server. If bind_and_activate is true, the constructor automatically attempts to invoke server_bind() and server_activate(). The other parameters are passed to the BaseServer base class.

class socketserver.UDPServer(server_address, RequestHandlerClass, bind_and_activate=True)

순서가 잘못되거나 전송 중 손실될 수 있는 이산적 정보 패킷인 데이터 그램을 사용합니다. 매개 변수는 TCPServer와 같습니다.

class socketserver.UnixStreamServer(server_address, RequestHandlerClass, bind_and_activate=True)

class socketserver.UnixDatagramServer(server_address, RequestHandlerClass, bind_and_activate=True)

TCP와 UDP 클래스와 비슷하지만, 유닉스 도메인 소켓을 사용하는 자주 사용되지 않는 클래스입니다; 유닉스 이외의 플랫폼에서는 사용할 수 없습니다. 매개 변수는 TCPServer와 같습니다.

이 네 가지 클래스는 동기적으로 (synchronously) 요청을 처리합니다; 다음 요청을 시작하기 전에 각 요청을 완료해야 합니다. 계산이 많이 필요하거나 클라이언트가 처리하는 속도가 느리도록 데이터를 많이 반환하기 때문에 각 요청을 완료하는 데 시간이 오래 걸리면 적합하지 않습니다. 해결책은 각 요청을 처리하기 위해 별도의 프로세스나 스레드를 만드는 것입니다; ForkingMixIn과 ThreadingMixIn 믹스인 클래스를 사용하여 비동기 동작을 지원할 수 있습니다.

서버를 만들려면 몇 가지 단계가 필요합니다. 먼저, BaseRequestHandler 클래스를 서브 클래싱하고 handle() 메서드를 재정의하여 요청 처리기 클래스를 만들어야 합니다; 이 메서드는 들어오는 요청을 처리합니다. 둘째, 서버 주소와 요청 처리기 클래스를 전달하여 서버 클래스 중 하나를 인스턴스 화해야 합니다. with 문에서 서버를 사용하는 것이 좋습니다. 그런 다음 서버 객체의 handle_request()나 serve_forever() 메서드를 호출하여 하나 이상의 요청을 처리합니다. 마지막으로, (with 문을 사용하지 않았다면) server_close()를 호출하여 소켓을 닫습니다.

스레드 연결 동작을 위해 ThreadingMixIn에서 상속할 때, 갑작스러운 종료 시 스레드 작동 방식을 명시적으로 선언해야 합니다. ThreadingMixIn 클래스는 서버가 스레드 종료를 기다려야 하는지를 가리키는 daemon_threads 어트리뷰트를 정의합니다. 스레드가 자율적으로 동작하게 하려면 플래그를 명시적으로 설정해야 합니다; 기본값은 False인데, ThreadingMixIn으로 만들어진 모든 스레드가 종료될 때까지 파이썬이 종료되지 않음을 뜻합니다.

서버 클래스는 사용하는 네트워크 프로토콜과 관계없이 같은 외부 메서드와 어트리뷰트를 갖습니다.

서버 생성 노트

상속 다이어그램에는 5개의 클래스가 있으며, 그중 4개는 4가지 유형의 동기 서버를 나타냅니다:

+------------+
| BaseServer |
+------------+
      |
      v
+-----------+        +------------------+
| TCPServer |------->| UnixStreamServer |
+-----------+        +------------------+
      |
      v
+-----------+        +--------------------+
| UDPServer |------->| UnixDatagramServer |
+-----------+        +--------------------+

Note that UnixDatagramServer derives from UDPServer, not from UnixStreamServer — the only difference between an IP and a Unix server is the address family.

class socketserver.ForkingMixIn

class socketserver.ThreadingMixIn

이러한 믹스인 클래스를 사용하여 각 서버 유형의 포킹(forking)과 스레딩(threading) 버전을 만들 수 있습니다. 예를 들어, ThreadingUDPServer는 다음과 같이 만듭니다:

class ThreadingUDPServer(ThreadingMixIn, UDPServer):
    pass

UDPServer에 정의된 메서드를 재정의하므로, 믹스인 클래스가 먼저 옵니다. 다양한 어트리뷰트를 설정하면 하부 서버 메커니즘의 동작도 변경됩니다.

아래 언급된 ForkingMixIn과 Forking 클래스들은 fork()를 지원하는 POSIX 플랫폼에서만 사용할 수 있습니다.

block_on_close

ForkingMixIn.server_close waits until all child processes complete, except if block_on_close attribute is False.

ThreadingMixIn.server_close waits until all non-daemon threads complete, except if block_on_close attribute is False.

max_children

Specify how many child processes will exist to handle requests at a time for ForkingMixIn. If the limit is reached, new requests will wait until one child process has finished.

daemon_threads

For ThreadingMixIn use daemonic threads by setting ThreadingMixIn.daemon_threads to True to not wait until threads complete.

버전 3.7에서 변경: ForkingMixIn.server_close and ThreadingMixIn.server_close now waits until all child processes and non-daemonic threads complete. Add a new ForkingMixIn.block_on_close class attribute to opt-in for the pre-3.7 behaviour.

class socketserver.ForkingTCPServer

class socketserver.ForkingUDPServer

class socketserver.ThreadingTCPServer

class socketserver.ThreadingUDPServer

class socketserver.ForkingUnixStreamServer

class socketserver.ForkingUnixDatagramServer

class socketserver.ThreadingUnixStreamServer

class socketserver.ThreadingUnixDatagramServer

이 클래스들이 믹스인 클래스를 사용하여 미리 정의됩니다.

Added in version 3.12: The ForkingUnixStreamServer and ForkingUnixDatagramServer classes were added.

서비스를 구현하려면, BaseRequestHandler에서 클래스를 파생시키고 handle() 메서드를 재정의해야 합니다. 그런 다음 서버 클래스 중 하나와 여러분의 요청 처리기 클래스를 결합하여 다양한 버전의 서비스를 실행할 수 있습니다. 요청 처리기 클래스는 데이터 그램과 스트림 서비스에서 달라야 합니다. 처리기 서브 클래스 StreamRequestHandler 나 DatagramRequestHandler를 사용하여 이 차이를 숨길 수 있습니다.

물론, 여전히 머리를 사용해야 합니다! 예를 들어, 서비스가 다른 요청으로 수정될 수 있는 메모리상의 상태를 포함할 때 포킹 서버를 사용하는 것은 의미가 없습니다. 자식 프로세스에의 수정은 부모 프로세스에 유지된 초기 상태에 도달하여 각 자식에 전달되지 못하기 때문입니다. 이 경우, 스레딩 서버를 사용할 수 있지만, 아마도 공유 데이터의 무결성을 보호하기 위해 록을 사용해야 합니다.

반면, 모든 데이터가 외부(예를 들어, 파일 시스템)에 저장되는 HTTP 서버를 구축한다면, 동기 클래스는 하나의 요청이 처리되는 동안 실질적으로 서비스가 “듣지 못하게” 만듭니다 – 클라이언트가 요청한 모든 데이터를 받는 속도가 느리다면 매우 오랜 시간이 걸릴 수 있습니다. 이럴 때는 스레딩이나 포킹 서버가 적합합니다.

때에 따라, 요청의 일부를 동기적으로 처리하는 것이 좋지만, 요청 데이터에 따라 포크 된 자식에서 처리를 완료하는 것이 적절할 수 있습니다. 이는 동기 서버를 사용하고 요청 처리기 클래스 handle() 메서드에서 명시적 포크를 수행하여 구현할 수 있습니다.

Another approach to handling multiple simultaneous requests in an environment that supports neither threads nor fork() (or where these are too expensive or inappropriate for the service) is to maintain an explicit table of partially finished requests and to use selectors to decide which request to work on next (or whether to handle a new incoming request). This is particularly important for stream services where each client can potentially be connected for a long time (if threads or subprocesses cannot be used).

서버 객체

class socketserver.BaseServer(server_address, RequestHandlerClass)

이것은 모듈에 있는 모든 서버 객체의 슈퍼 클래스입니다. 아래에 주어진 인터페이스를 정의하지만, 대부분의 메서드를 구현하지 않고, 서브 클래스에서 구현됩니다. 두 개의 매개 변수는 각각 server_address와 RequestHandlerClass 어트리뷰트에 저장됩니다.

fileno()

서버가 리스닝 중인 소켓의 정수 파일 디스크립터를 반환합니다. 이 함수는 가장 일반적으로 같은 프로세스에서 여러 서버를 모니터링할 수 있도록 selectors에 전달됩니다.

handle_request()

단일 요청을 처리합니다. 이 함수는 다음 메서드들을 차례로 호출합니다: get_request(), verify_request() 및 process_request(). 처리기 클래스의 사용자 제공 handle() 메서드에서 예외가 발생하면, 서버의 handle_error() 메서드가 호출됩니다. timeout 초 내에 요청이 수신되지 않으면, handle_timeout()이 호출되고 handle_request()는 반환합니다.

serve_forever(poll_interval=0.5)

명시적인 shutdown() 요청이 있을 때까지 요청을 처리합니다. poll_interval 초마다 shutdown을 확인합니다. timeout 어트리뷰트를 무시합니다. 또한 service_actions()를 호출하는데, 서브 클래스나 믹스인이 주어진 서비스에 특정한 동작을 제공하기 위해 사용할 수 있습니다. 예를 들어, ForkingMixIn 클래스는 service_actions()를 사용하여 좀비 자식 프로세스를 정리합니다.

버전 3.3에서 변경: serve_forever 메서드에 service_actions 호출을 추가했습니다.

service_actions()

serve_forever() 루프에서 호출됩니다. 이 메서드는 서브 클래스나 믹스인 클래스에서 재정의되어 정리 조치와 같은 지정된 서비스에 특정한 조치를 수행할 수 있습니다.

Added in version 3.3.

shutdown()

serve_forever() 루프가 정지하도록 하고 정지할 때까지 기다립니다. serve_forever()가 다른 스레드에서 실행되는 동안 shutdown()을 호출해야 합니다. 그렇지 않으면 교착 상태가 됩니다.

server_close()

서버를 정리합니다. 재정의될 수 있습니다.

address_family

서버 소켓이 속한 프로토콜 패밀리. 일반적인 예는 socket.AF_INET과 socket.AF_UNIX입니다.

RequestHandlerClass

사용자 제공 요청 처리기 클래스; 요청마다 이 클래스의 인스턴스가 만들어집니다.

server_address

The address on which the server is listening. The format of addresses varies depending on the protocol family; see the documentation for the socket module for details. For internet protocols, this is a tuple containing a string giving the address, and an integer port number: ('127.0.0.1', 80), for example.

socket

서버가 들어오는 요청을 리스닝 할 소켓 객체.

서버 클래스는 다음 클래스 변수를 지원합니다:

allow_reuse_address

서버가 주소를 재사용하도록 허락하는지 여부. 기본값은 False이며, 정책을 변경하기 위해 서브 클래스에서 설정할 수 있습니다.

request_queue_size

요청 큐의 크기. 단일 요청을 처리하는 데 시간이 오래 걸리면, 서버가 바쁠 때 도착한 요청은 최대 request_queue_size 요청까지 큐에 배치됩니다. 큐가 가득 차면, 클라이언트의 추가 요청은 “연결 거부(Connection denied)” 에러를 받게 됩니다. 기본값은 일반적으로 5이지만, 서브 클래스가 재정의할 수 있습니다.

socket_type

서버가 사용하는 소켓의 유형. socket.SOCK_STREAM과 socket.SOCK_DGRAM은 두 가지 흔한 값입니다.

timeout

초 단위의 시간제한 기간, 또는 시간제한이 필요하지 않으면 None. handle_request()가 timeout 기간 내에 들어오는 요청을 받지 못하면, handle_timeout() 메서드가 호출됩니다.

TCPServer와 같은 베이스 서버 클래스의 서브 클래스가 재정의할 수 있는 다양한 서버 메서드가 있습니다; 이러한 메서드는 서버 객체의 외부 사용자에게는 유용하지 않습니다.

finish_request(request, client_address)

RequestHandlerClass를 인스턴스화하고 handle() 메서드를 호출하여 실제로 요청을 처리합니다.

get_request()

소켓으로부터의 요청을 받아들이고, 클라이언트와 통신하는 데 사용될 새 소켓 객체와 클라이언트 주소를 포함하는 2-튜플을 반환해야 합니다.

handle_error(request, client_address)

RequestHandlerClass 인스턴스의 handle() 메서드에서 예외가 발생하면 이 함수가 호출됩니다. 기본 액션은 표준 에러로 트레이스백을 인쇄하고 추가 요청을 계속 처리하는 것입니다.

버전 3.6에서 변경: 이제 Exception 클래스에서 파생된 예외에 대해서만 호출됩니다.

handle_timeout()

이 함수는 timeout 어트리뷰트가 None 이외의 값으로 설정되고 요청이 수신되지 않은 채로 시간제한 기간이 지나면 호출됩니다. 포킹 서버에서의 기본 액션은 종료한 모든 자식 프로세스의 상태를 수집하는 것이고, 반면에 스레딩 서버에서는 이 메서드가 아무 작업도 수행하지 않습니다.

process_request(request, client_address)

finish_request()를 호출하여 RequestHandlerClass 의 인스턴스를 만듭니다. 원한다면, 이 함수는 요청을 처리하기 위해 새 프로세스나 스레드를 만들 수 있습니다; ForkingMixIn과 ThreadingMixIn 클래스가 그렇게 합니다.

server_activate()

서버를 활성화하기 위해 서버의 생성자가 호출합니다. TCP 서버의 기본 동작은 단지 서버의 소켓에 대해 listen()을 호출합니다. 재정의될 수 있습니다.

server_bind()

소켓을 원하는 주소에 바인딩하기 위해 서버의 생성자가 호출합니다. 재정의될 수 있습니다.

verify_request(request, client_address)

불리언 값을 반환해야 합니다; 값이 True이면, 요청이 처리되고, False이면, 요청이 거부됩니다. 서버에 대한 액세스 제어를 구현하기 위해 이 함수를 재정의할 수 있습니다. 기본 구현은 항상 True를 반환합니다.

버전 3.6에서 변경: 컨텍스트 관리자 프로토콜에 대한 지원이 추가되었습니다. 컨텍스트 관리자를 벗어나는 것은 server_close()를 호출하는 것과 동등합니다.

요청 처리기 객체

class socketserver.BaseRequestHandler

이것은 모든 요청 처리기 객체의 슈퍼 클래스입니다. 아래에 주어진 인터페이스를 정의합니다. 구상 요청 처리기 서브 클래스는 새 handle() 메서드를 정의해야 하며, 다른 메서드를 재정의할 수 있습니다. 각 요청에 대해 서브 클래스의 새 인스턴스가 만들어집니다.

setup()

필요한 초기화 액션을 수행하기 위해 handle() 메서드 전에 호출됩니다. 기본 구현은 아무것도 수행하지 않습니다.

handle()

This function must do all the work required to service a request. The default implementation does nothing. Several instance attributes are available to it; the request is available as request; the client address as client_address; and the server instance as server, in case it needs access to per-server information.

The type of request is different for datagram or stream services. For stream services, request is a socket object; for datagram services, request is a pair of string and socket.

finish()

필요한 정리 액션을 수행하기 위해 handle() 메서드 이후에 호출됩니다. 기본 구현은 아무것도 수행하지 않습니다. setup()에서 예외가 발생하면, 이 함수가 호출되지 않습니다.

request

The new socket.socket object to be used to communicate with the client.

client_address

Client address returned by BaseServer.get_request().

server

BaseServer object used for handling the request.

class socketserver.StreamRequestHandler

class socketserver.DatagramRequestHandler

These BaseRequestHandler subclasses override the setup() and finish() methods, and provide rfile and wfile attributes.

rfile

A file object from which receives the request is read. Support the io.BufferedIOBase readable interface.

wfile

A file object to which the reply is written. Support the io.BufferedIOBase writable interface

버전 3.6에서 변경: wfile also supports the io.BufferedIOBase writable interface.

예

socketserver.TCPServer 예

이것은 서버 쪽입니다:

import socketserver

class MyTCPHandler(socketserver.BaseRequestHandler):
    """
    The request handler class for our server.

    It is instantiated once per connection to the server, and must
    override the handle() method to implement communication to the
    client.
    """

    def handle(self):
        # self.request is the TCP socket connected to the client
        self.data = self.request.recv(1024).strip()
        print("Received from {}:".format(self.client_address[0]))
        print(self.data)
        # just send back the same data, but upper-cased
        self.request.sendall(self.data.upper())

if __name__ == "__main__":
    HOST, PORT = "localhost", 9999

    # Create the server, binding to localhost on port 9999
    with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server:
        # Activate the server; this will keep running until you
        # interrupt the program with Ctrl-C
        server.serve_forever()

스트림(표준 파일 인터페이스를 제공하여 통신을 단순화하는 파일류 객체)을 사용하는 대체 요청 처리기 클래스:

class MyTCPHandler(socketserver.StreamRequestHandler):

    def handle(self):
        # self.rfile is a file-like object created by the handler;
        # we can now use e.g. readline() instead of raw recv() calls
        self.data = self.rfile.readline().strip()
        print("{} wrote:".format(self.client_address[0]))
        print(self.data)
        # Likewise, self.wfile is a file-like object used to write back
        # to the client
        self.wfile.write(self.data.upper())

The difference is that the readline() call in the second handler will call recv() multiple times until it encounters a newline character, while the single recv() call in the first handler will just return what has been received so far from the client’s sendall() call (typically all of it, but this is not guaranteed by the TCP protocol).

이것은 클라이언트 쪽입니다:

import socket
import sys

HOST, PORT = "localhost", 9999
data = " ".join(sys.argv[1:])

# Create a socket (SOCK_STREAM means a TCP socket)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
    # Connect to server and send data
    sock.connect((HOST, PORT))
    sock.sendall(bytes(data + "\n", "utf-8"))

    # Receive data from the server and shut down
    received = str(sock.recv(1024), "utf-8")

print("Sent:     {}".format(data))
print("Received: {}".format(received))

예제의 결과는 다음과 같아야 합니다:

서버:

$ python TCPServer.py
127.0.0.1 wrote:
b'hello world with TCP'
127.0.0.1 wrote:
b'python is nice'

클라이언트:

$ python TCPClient.py hello world with TCP
Sent:     hello world with TCP
Received: HELLO WORLD WITH TCP
$ python TCPClient.py python is nice
Sent:     python is nice
Received: PYTHON IS NICE

socketserver.UDPServer 예

이것은 서버 쪽입니다:

import socketserver

class MyUDPHandler(socketserver.BaseRequestHandler):
    """
    This class works similar to the TCP handler class, except that
    self.request consists of a pair of data and client socket, and since
    there is no connection the client address must be given explicitly
    when sending data back via sendto().
    """

    def handle(self):
        data = self.request[0].strip()
        socket = self.request[1]
        print("{} wrote:".format(self.client_address[0]))
        print(data)
        socket.sendto(data.upper(), self.client_address)

if __name__ == "__main__":
    HOST, PORT = "localhost", 9999
    with socketserver.UDPServer((HOST, PORT), MyUDPHandler) as server:
        server.serve_forever()

이것은 클라이언트 쪽입니다:

import socket
import sys

HOST, PORT = "localhost", 9999
data = " ".join(sys.argv[1:])

# SOCK_DGRAM is the socket type to use for UDP sockets
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# As you can see, there is no connect() call; UDP has no connections.
# Instead, data is directly sent to the recipient via sendto().
sock.sendto(bytes(data + "\n", "utf-8"), (HOST, PORT))
received = str(sock.recv(1024), "utf-8")

print("Sent:     {}".format(data))
print("Received: {}".format(received))

예제의 출력은 TCP 서버 예제와 정확히 같아야 합니다.

비동기 믹스인

비동기 처리기를 구축하려면, ThreadingMixIn 과 ForkingMixIn 클래스를 사용하십시오.

ThreadingMixIn 클래스의 예:

import socket
import threading
import socketserver

class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):

    def handle(self):
        data = str(self.request.recv(1024), 'ascii')
        cur_thread = threading.current_thread()
        response = bytes("{}: {}".format(cur_thread.name, data), 'ascii')
        self.request.sendall(response)

class ThreadedTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
    pass

def client(ip, port, message):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        sock.connect((ip, port))
        sock.sendall(bytes(message, 'ascii'))
        response = str(sock.recv(1024), 'ascii')
        print("Received: {}".format(response))

if __name__ == "__main__":
    # Port 0 means to select an arbitrary unused port
    HOST, PORT = "localhost", 0

    server = ThreadedTCPServer((HOST, PORT), ThreadedTCPRequestHandler)
    with server:
        ip, port = server.server_address

        # Start a thread with the server -- that thread will then start one
        # more thread for each request
        server_thread = threading.Thread(target=server.serve_forever)
        # Exit the server thread when the main thread terminates
        server_thread.daemon = True
        server_thread.start()
        print("Server loop running in thread:", server_thread.name)

        client(ip, port, "Hello World 1")
        client(ip, port, "Hello World 2")
        client(ip, port, "Hello World 3")

        server.shutdown()

예제의 결과는 다음과 같아야 합니다:

$ python ThreadedTCPServer.py
Server loop running in thread: Thread-1
Received: Thread-2: Hello World 1
Received: Thread-3: Hello World 2
Received: Thread-4: Hello World 3

ForkingMixIn 클래스는 서버가 요청마다 새 프로세스를 생성한다는 점을 제외하고 같은 방식으로 사용됩니다. fork()를 지원하는 POSIX 플랫폼에서만 사용 가능합니다.

http.server — HTTP servers

소스 코드: Lib/http/server.py [https://github.com/python/cpython/tree/main/Lib/http/server.py]

This module defines classes for implementing HTTP servers.

경고

http.server is not recommended for production. It only implements basic security checks.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

HTTPServer 클래스는 socketserver.TCPServer 서브 클래스입니다. HTTP 소켓을 만들고 리스닝하면서 요청을 처리기로 디스패치 합니다. 서버를 만들고 실행하는 코드는 다음과 같습니다:

def run(server_class=HTTPServer, handler_class=BaseHTTPRequestHandler):
    server_address = ('', 8000)
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()

class http.server.HTTPServer(server_address, RequestHandlerClass)

이 클래스는 TCPServer 클래스를 기반으로 하고, 서버 주소를 server_name과 server_port라는 인스턴스 변수로 저장합니다. 처리기는 일반적으로 처리기의 server 인스턴스 변수를 통해 서버에 액세스 할 수 있습니다.

class http.server.ThreadingHTTPServer(server_address, RequestHandlerClass)

이 클래스는 HTTPServer와 동일하지만 ThreadingMixIn을 사용하여 요청을 처리하는 데 스레드를 사용합니다. HTTPServer가 무기한 대기하도록 만드는 소켓을 미리 여는 웹 브라우저를 처리하는 데 유용합니다.

Added in version 3.7.

HTTPServer와 ThreadingHTTPServer는 인스턴스 화할 때 RequestHandlerClass를 제공해야 하며, 이 모듈은 세 가지 변형을 제공합니다:

class http.server.BaseHTTPRequestHandler(request, client_address, server)

이 클래스는 서버에 도착하는 HTTP 요청을 처리하는 데 사용됩니다. 그 자체로는, 실제 HTTP 요청에 응답할 수 없습니다; 각 요청 메서드(예를 들어 GET이나 POST)를 처리하려면 서브 클래스를 만들어야 합니다. BaseHTTPRequestHandler는 많은 클래스 및 인스턴스 변수와 서브 클래스가 사용할 메서드를 제공합니다.

The handler will parse the request and the headers, then call a method specific to the request type. The method name is constructed from the request. For example, for the request method SPAM, the do_SPAM() method will be called with no arguments. All of the relevant information is stored in instance variables of the handler. Subclasses should not need to override or extend the __init__() method.

BaseHTTPRequestHandler에는 다음과 같은 인스턴스 변수가 있습니다:

client_address

클라이언트 주소를 나타내는 (host, port) 형식의 튜플을 포함합니다.

server

서버 인스턴스를 포함합니다.

close_connection

handle_one_request()가 반환되기 전에 설정해야 하는 불리언으로, 다른 요청이 기대되는지, 또는 연결을 종료해야 하는지를 나타냅니다.

requestline

HTTP 요청 줄의 문자열 표현을 포함합니다. 종료 CRLF가 제거됩니다. 이 어트리뷰트는 handle_one_request()에서 설정해야 합니다. 유효한 요청 줄이 처리되지 않았으면, 빈 문자열로 설정해야 합니다.

command

명령(요청 유형)을 포함합니다. 예를 들어, 'GET'.

path

Contains the request path. If query component of the URL is present, then path includes the query. Using the terminology of RFC 3986 [https://datatracker.ietf.org/doc/html/rfc3986.html], path here includes hier-part and the query.

request_version

요청의 버전 문자열을 포함합니다. 예를 들어, 'HTTP/1.0'.

headers

MessageClass 클래스 변수로 지정된 클래스의 인스턴스를 보유합니다. 이 인스턴스는 HTTP 요청의 헤더를 구문 분석하고 관리합니다. http.client의 parse_headers() 함수가 헤더를 구문 분석하는 데 사용되며 HTTP 요청이 유효한 RFC 2822 [https://datatracker.ietf.org/doc/html/rfc2822.html] 스타일 헤더를 제공할 것을 요구합니다.

rfile

선택적 입력 데이터의 시작부터 읽을 준비가 된 io.BufferedIOBase 입력 스트림.

wfile

클라이언트로 돌려줄 응답을 쓰기 위한 출력 스트림을 포함합니다. HTTP 클라이언트와의 성공적인 상호 운용을 위해서 이 스트림에 쓸 때 HTTP 프로토콜을 올바르게 준수해야 합니다.

버전 3.6에서 변경: 이것은 io.BufferedIOBase 스트림입니다.

BaseHTTPRequestHandler에는 다음과 같은 어트리뷰트가 있습니다:

server_version

서버 소프트웨어 버전을 지정합니다. 이것을 재정의하고 싶을 수 있습니다. 형식은 여러 공백으로 구분된 문자열이며, 각 문자열은 name[/version] 형식입니다. 예를 들어, 'BaseHTTP/0.2'.

sys_version

version_string 메서드와 server_version 클래스 변수에서 사용할 수 있는 형식으로 파이썬 시스템 버전을 포함합니다. 예를 들어, 'Python/1.4'.

error_message_format

클라이언트에 대한 에러 응답을 빌드하기 위해 send_error() 메서드에서 사용해야 하는 포맷 문자열을 지정합니다. 문자열은 기본적으로 send_error()에 전달된 상태 코드에 따라 responses의 변수로 채워집니다.

error_content_type

클라이언트로 전송되는 에러 응답의 Content-Type HTTP 헤더를 지정합니다. 기본값은 'text/html'입니다.

protocol_version

Specifies the HTTP version to which the server is conformant. It is sent in responses to let the client know the server’s communication capabilities for future requests. If set to 'HTTP/1.1', the server will permit HTTP persistent connections; however, your server must then include an accurate Content-Length header (using send_header()) in all of its responses to clients. For backwards compatibility, the setting defaults to 'HTTP/1.0'.

MessageClass

HTTP 헤더를 구문 분석할 email.message.Message와 유사한 클래스를 지정합니다. 일반적으로, 이는 재정의되지 않으며, 기본값은 http.client.HTTPMessage입니다.

responses

이 어트리뷰트에는 에러 코드 정수에서 짧고 긴 메시지를 포함하는 두 요소 튜플로의 매핑이 포함됩니다. 예를 들어, {code: (shortmessage, longmessage)}. shortmessage는 일반적으로 에러 응답에서 message 키로 사용되고, longmessage는 explain 키로 사용됩니다. send_response_only()와 send_error() 메서드에서 사용됩니다.

BaseHTTPRequestHandler 인스턴스에는 다음과 같은 메서드가 있습니다:

handle()

Calls handle_one_request() once (or, if persistent connections are enabled, multiple times) to handle incoming HTTP requests. You should never need to override it; instead, implement appropriate do_*() methods.

handle_one_request()

This method will parse and dispatch the request to the appropriate do_*() method. You should never need to override it.

handle_expect_100()

When an HTTP/1.1 conformant server receives an Expect: 100-continue request header it responds back with a 100 Continue followed by 200 OK headers. This method can be overridden to raise an error if the server does not want the client to continue. For e.g. server can choose to send 417 Expectation Failed as a response header and return False.

Added in version 3.2.

send_error(code, message=None, explain=None)

Sends and logs a complete error reply to the client. The numeric code specifies the HTTP error code, with message as an optional, short, human readable description of the error. The explain argument can be used to provide more detailed information about the error; it will be formatted using the error_message_format attribute and emitted, after a complete set of headers, as the response body. The responses attribute holds the default values for message and explain that will be used if no value is provided; for unknown codes the default value for both is the string ???. The body will be empty if the method is HEAD or the response code is one of the following: 1xx, 204 No Content, 205 Reset Content, 304 Not Modified.

버전 3.4에서 변경: 에러 응답에는 Content-Length 헤더가 포함됩니다. explain 인자를 추가했습니다.

send_response(code, message=None)

헤더 버퍼에 응답 헤더를 추가하고 받아들인 요청을 로깅 합니다. HTTP 응답 줄이 내부 버퍼에 기록되고, Server와 Date 헤더가 뒤따릅니다. 이 두 헤더의 값은 각각 version_string()과 date_time_string() 메서드에서 취합니다. 서버가 send_header() 메서드를 사용하여 다른 헤더를 보내려고 하지 않는다면, send_response() 다음에 end_headers() 호출이 있어야 합니다.

버전 3.3에서 변경: 헤더는 내부 버퍼에 저장되며 end_headers()를 명시적으로 호출해야 합니다.

send_header(keyword, value)

end_headers()나 flush_headers()가 호출될 때 출력 스트림에 기록될 내부 버퍼에 HTTP 헤더를 추가합니다. keyword는 헤더 키워드를 지정하고, value는 값을 지정해야 합니다. send_header 호출이 완료된 후, 작업을 완료하려면 반드시 end_headers()를 호출해야 함에 유의하십시오.

버전 3.2에서 변경: 헤더는 내부 버퍼에 저장됩니다.

send_response_only(code, message=None)

응답 헤더만 보내는데, 서버가 100 Continue 응답을 클라이언트로 전송할 목적으로 사용됩니다. 헤더는 버퍼링 되지 않고 출력 스트림으로 직접 전송합니다. message를 지정하지 않으면, 응답 code에 해당하는 HTTP 메시지가 전송됩니다.

Added in version 3.2.

end_headers()

Adds a blank line (indicating the end of the HTTP headers in the response) to the headers buffer and calls flush_headers().

버전 3.2에서 변경: 버퍼링 된 헤더는 출력 스트림에 기록됩니다.

flush_headers()

마지막으로 헤더를 출력 스트림으로 보내고 내부 헤더 버퍼를 플러시 합니다.

Added in version 3.3.

log_request(code='-', size='-')

받아들인 (성공적인) 요청을 로깅 합니다. code는 응답과 관련된 숫자 HTTP 코드를 지정해야 합니다. 응답의 크기가 있으면, size 매개 변수로 전달되어야 합니다.

log_error(...)

요청을 이행할 수 없을 때 에러를 로깅 합니다. 기본적으로, 메시지를 log_message()에 전달하므로, 같은 인자(format과 추가 값)를 취합니다.

log_message(format, ...)

sys.stderr에 임의의 메시지를 로깅 합니다. 이것은 일반적으로 사용자 지정 에러 로깅 메커니즘을 만들기 위해 재정의됩니다. format 인자는 표준 printf 스타일 포맷 문자열이며, log_message()에 대한 추가 인자는 포매팅의 입력으로 적용됩니다. 클라이언트 ip 주소와 현재 날짜 및 시간은 로깅 되는 모든 메시지 앞에 붙습니다.

version_string()

서버 소프트웨어의 버전 문자열을 반환합니다. 이것은 server_version과 sys_version 어트리뷰트의 조합입니다.

date_time_string(timestamp=None)

timestamp(None이거나 time.time()이 반환한 형식이어야 합니다)로 지정된 날짜와 시간을 메시지 헤더용으로 포맷하여 반환합니다. timestamp를 생략하면, 현재 날짜와 시간이 사용됩니다.

결과는 'Sun, 06 Nov 1994 08:49:37 GMT'와 같은 모습입니다.

log_date_time_string()

로깅용으로 포맷한 현재 날짜와 시간을 반환합니다.

address_string()

클라이언트 주소를 반환합니다.

버전 3.3에서 변경: 이전에는, 이름 조회가 수행되었습니다. 이름 결정(name resolution) 지연을 피하고자, 이제 항상 IP 주소를 반환합니다.

class http.server.SimpleHTTPRequestHandler(request, client_address, server, directory=None)

This class serves files from the directory directory and below, or the current directory if directory is not provided, directly mapping the directory structure to HTTP requests.

버전 3.7에서 변경: Added the directory parameter.

버전 3.9에서 변경: The directory parameter accepts a path-like object.

요청 구문 분석과 같은 많은 작업이 베이스 클래스 BaseHTTPRequestHandler 에 의해 수행됩니다. 이 클래스는 do_GET()과 do_HEAD() 함수를 구현합니다.

다음은 SimpleHTTPRequestHandler 의 클래스 수준 어트리뷰트로 정의됩니다:

server_version

이것은 "SimpleHTTP/" + __version__이며, 여기서 __version__은 모듈 수준에서 정의됩니다.

extensions_map

접미사를 MIME 형식으로 매핑하는 딕셔너리. 기본 시스템 매핑에 대한 사용자 정의 재정의를 포함합니다. 매핑은 대소 문자를 구분 없이 사용되므로, 소문자 키만 포함해야 합니다.

버전 3.9에서 변경: 이 딕셔너리는 더는 기본 시스템 매핑으로 채워지지 않고, 재정의 만 포함합니다.

SimpleHTTPRequestHandler 클래스는 다음 메서드를 정의합니다:

do_HEAD()

이 메서드는 'HEAD' 요청 유형을 제공합니다: 동등한 GET 요청에 대해 전송할 헤더를 전송합니다. 가능한 헤더에 대한 더 완전한 설명은 do_GET() 메서드를 참조하십시오.

do_GET()

요청을 현재 작업 디렉터리에 상대적인 경로로 해석하여 요청은 로컬 파일에 매핑됩니다.

요청이 디렉터리에 매핑되었으면, 디렉터리는 index.html이나 index.htm (이 순서대로) 파일을 검사합니다. 발견되면, 파일 내용이 반환됩니다; 그렇지 않으면 list_directory() 메서드를 호출하여 디렉터리 목록이 생성됩니다. 이 메서드는 os.listdir()을 사용하여 디렉터리를 스캔하고, listdir()이 실패하면 404 에러 응답을 반환합니다.

If the request was mapped to a file, it is opened. Any OSError exception in opening the requested file is mapped to a 404, 'File not found' error. If there was an 'If-Modified-Since' header in the request, and the file was not modified after this time, a 304, 'Not Modified' response is sent. Otherwise, the content type is guessed by calling the guess_type() method, which in turn uses the extensions_map variable, and the file contents are returned.

추측된 콘텐츠 유형의 'Content-type:' 헤더가 출력되고, 파일 크기가 담긴 'Content-Length:' 헤더와 파일 수정 시간이 담긴 'Last-Modified:' 헤더가 뒤따릅니다.

그런 다음 헤더의 끝을 나타내는 빈 줄이 따라온 후에, 파일의 내용이 출력됩니다. 파일의 MIME 유형이 text/로 시작하면 파일은 텍스트 모드로 열립니다; 그렇지 않으면 바이너리 모드가 사용됩니다.

For example usage, see the implementation of the test function in Lib/http/server.py [https://github.com/python/cpython/tree/main/Lib/http/server.py].

버전 3.7에서 변경: 'If-Modified-Since' 헤더 지원.

SimpleHTTPRequestHandler 클래스는 현재 디렉터리를 기준으로 파일을 제공하는 매우 기본적인 웹 서버를 만들기 위해 다음과 같은 방식으로 사용될 수 있습니다:

import http.server
import socketserver

PORT = 8000

Handler = http.server.SimpleHTTPRequestHandler

with socketserver.TCPServer(("", PORT), Handler) as httpd:
    print("serving at port", PORT)
    httpd.serve_forever()

SimpleHTTPRequestHandler can also be subclassed to enhance behavior, such as using different index file names by overriding the class attribute index_pages.

http.server can also be invoked directly using the -m switch of the interpreter. Similar to the previous example, this serves files relative to the current directory:

python -m http.server

The server listens to port 8000 by default. The default can be overridden by passing the desired port number as an argument:

python -m http.server 9000

By default, the server binds itself to all interfaces. The option -b/--bind specifies a specific address to which it should bind. Both IPv4 and IPv6 addresses are supported. For example, the following command causes the server to bind to localhost only:

python -m http.server --bind 127.0.0.1

버전 3.4에서 변경: Added the --bind option.

버전 3.8에서 변경: Support IPv6 in the --bind option.

By default, the server uses the current directory. The option -d/--directory specifies a directory to which it should serve the files. For example, the following command uses a specific directory:

python -m http.server --directory /tmp/

버전 3.7에서 변경: Added the --directory option.

By default, the server is conformant to HTTP/1.0. The option -p/--protocol specifies the HTTP version to which the server is conformant. For example, the following command runs an HTTP/1.1 conformant server:

python -m http.server --protocol HTTP/1.1

버전 3.11에서 변경: Added the --protocol option.

class http.server.CGIHTTPRequestHandler(request, client_address, server)

이 클래스는 현재 디렉터리와 그 아래에 있는 파일이나 CGI 스크립트의 출력을 제공하는 데 사용됩니다. HTTP 계층 구조를 로컬 디렉터리 구조에 매핑하는 것은 SimpleHTTPRequestHandler와 정확히 같음에 유의하십시오.

참고

CGIHTTPRequestHandler 클래스가 실행하는 CGI 스크립트는 리디렉션(HTTP 코드 302)을 실행할 수 없습니다, CGI 스크립트를 실행하기 전에 코드 200(스크립트 출력이 이어집니다)이 전송되기 때문입니다. 이것은 상태 코드를 선점합니다.

클래스는 CGI 스크립트라고 생각되면 파일로 제공하는 대신 CGI 스크립트를 실행합니다. 디렉터리 기반 CGI만 사용됩니다 — 다른 일반적인 서버 구성은 특수한 확장자를 CGI 스크립트를 나타내는 것으로 취급하는 것입니다.

요청이 cgi_directories 경로 아래로 이어지면, 파일을 제공하는 대신 CGI 스크립트를 실행하고 출력을 제공하도록 do_GET()과 do_HEAD() 함수가 수정되었습니다.

CGIHTTPRequestHandler는 다음 데이터 멤버를 정의합니다:

cgi_directories

기본값은 ['/cgi-bin', '/htbin']이며 CGI 스크립트를 포함하는 것으로 취급할 디렉터리를 기술합니다.

CGIHTTPRequestHandler는 다음 메서드를 정의합니다:

do_POST()

이 메서드는 'POST' 요청 유형을 제공하며, CGI 스크립트에만 허용됩니다. CGI 이외의 url에 POST를 시도할 때 에러 501, “Can only POST to CGI scripts”가 출력됩니다.

보안상의 이유로, CGI 스크립트는 nobody 사용자의 UID로 실행됨에 유의하십시오. CGI 스크립트 문제는 에러 403으로 변환됩니다.

Deprecated since version 3.13, will be removed in version 3.15: CGIHTTPRequestHandler is being removed in 3.15. CGI has not been considered a good way to do things for well over a decade. This code has been unmaintained for a while now and sees very little practical use. Retaining it could lead to further security considerations.

--cgi 옵션을 전달하여 명령 줄에서 CGIHTTPRequestHandler를 사용할 수 있습니다:

python -m http.server --cgi

Deprecated since version 3.13, will be removed in version 3.15: http.server command line --cgi support is being removed because CGIHTTPRequestHandler is being removed.

경고

CGIHTTPRequestHandler and the --cgi command line option are not intended for use by untrusted clients and may be vulnerable to exploitation. Always use within a secure environment.

Security Considerations

SimpleHTTPRequestHandler will follow symbolic links when handling requests, this makes it possible for files outside of the specified directory to be served.

Earlier versions of Python did not scrub control characters from the log messages emitted to stderr from python -m http.server or the default BaseHTTPRequestHandler .log_message implementation. This could allow remote clients connecting to your server to send nefarious control codes to your terminal.

버전 3.12에서 변경: Control characters are scrubbed in stderr logs.

http.cookies — HTTP state management

소스 코드: Lib/http/cookies.py [https://github.com/python/cpython/tree/main/Lib/http/cookies.py]

http.cookies 모듈은 HTTP 상태 관리 메커니즘인 쿠키의 개념을 추상화하는 클래스를 정의합니다. 그것은 단순한 문자열 전용 쿠키를 지원하고, 동시에 직렬화 가능한 데이터형을 쿠키값으로 갖는 데 필요한 추상화를 제공합니다.

The module formerly strictly applied the parsing rules described in the RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] and RFC 2068 [https://datatracker.ietf.org/doc/html/rfc2068.html] specifications. It has since been discovered that MSIE 3.0x didn’t follow the character rules outlined in those specs; many current-day browsers and servers have also relaxed parsing rules when it comes to cookie handling. As a result, this module now uses parsing rules that are a bit less strict than they once were.

The character set, string.ascii_letters, string.digits and !#$%&'*+-.^_`|~: denote the set of valid characters allowed by this module in a cookie name (as key).

버전 3.3에서 변경: Allowed ‘:’ as a valid cookie name character.

참고

잘못된 쿠키가 발견되면, CookieError가 발생하므로, 쿠키 데이터가 브라우저에서 제공되면 항상 잘못된 데이터일 가능성에 대비하고 구문 분석할 때 CookieError를 잡아야 합니다.

exception http.cookies.CookieError

RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 위반으로 인해 실패하는 예외: 잘못된 어트리뷰트, 잘못된 Set-Cookie 헤더 등

class http.cookies.BaseCookie([input])

이 클래스는 키가 문자열이고 값이 Morsel 인스턴스인 딕셔너리 형 객체입니다. 키에 값을 설정하면, 값이 먼저 키와 값이 포함된 Morsel로 변환됩니다.

input이 주어지면, load() 메서드로 전달됩니다.

class http.cookies.SimpleCookie([input])

This class derives from BaseCookie and overrides value_decode() and value_encode(). SimpleCookie supports strings as cookie values. When setting the value, SimpleCookie calls the builtin str() to convert the value to a string. Values received from HTTP are kept as strings.

더 보기

모듈 http.cookiejar

웹 클라이언트용 HTTP 쿠키 처리. http.cookiejar와 http.cookies 모듈 간의 의존성은 없습니다.

RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] - HTTP State Management Mechanism (HTTP 상태 관리 메커니즘)

이것은 이 모듈이 구현한 상태 관리 명세입니다.

쿠키 객체

BaseCookie.value_decode(val)

문자열 표현으로부터 튜플 (real_value, coded_value)를 반환합니다. real_value는 모든 형이 될 수 있습니다. 이 메서드는 BaseCookie에서는 아무런 디코딩을 하지 않습니다 — 재정의할 수 있도록 존재합니다.

BaseCookie.value_encode(val)

튜플 (real_value, coded_value)를 반환합니다. val은 모든 형이 될 수 있지만, coded_value는 항상 문자열로 변환됩니다. 이 메서드는 BaseCookie에서는 아무런 인코딩을 하지 않습니다 — 재정의할 수 있도록 존재합니다.

일반적으로, value_encode()와 value_decode()는 value_decode 범위에서 역연산입니다.

BaseCookie.output(attrs=None, header='Set-Cookie:', sep='\r\n')

HTTP 헤더로서 송신하기 적절한 문자열 표현을 반환합니다. attrs와 header는 각 Morsel의 output() 메서드로 전송됩니다. sep는 헤더를 함께 결합하는 데 사용되며, 기본적으로 '\r\n' (CRLF) 조합입니다.

BaseCookie.js_output(attrs=None)

자바스크립트를 지원하는 브라우저에서 실행될 때 HTTP 헤더가 전송된 것처럼 작동하는, 삽입 가능한 자바스크립트 코드 조각을 반환합니다.

attrs의 의미는 output()과 같습니다.

BaseCookie.load(rawdata)

rawdata가 문자열이면, HTTP_COOKIE로 구문 분석하고 거기에 있는 값을 Morsel로 추가합니다. 딕셔너리면, 다음과 동등합니다:

for k, v in rawdata.items():
    cookie[k] = v

Morsel 객체

class http.cookies.Morsel

RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 어트리뷰트를 포함하는 키/값 쌍을 추상화합니다.

Morsels are dictionary-like objects, whose set of keys is constant — the valid RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] attributes, which are:

expires

path

comment

domain

max-age

secure

version

httponly

samesite

httponly 어트리뷰트는 쿠키가 HTTP 요청으로만 전송되고 자바스크립트를 통해 액세스할 수 없도록 지정합니다. 이것은 교차 사이트 스크립팅의 일부 형식을 방지하기 위한 것입니다.

어트리뷰트 samesite는 브라우저가 교차 사이트 요청에 쿠키를 보낼 수 없도록 지정합니다. 이는 CSRF 공격을 완화하는 데 도움이 됩니다. 이 어트리뷰트의 유효한 값은 “Strict” 와 “Lax” 입니다.

키는 대소 문자를 구분하지 않으며 기본값은 ''입니다.

버전 3.5에서 변경: __eq__() now takes key and value into account.

버전 3.7에서 변경: 어트리뷰트 key, value 및 coded_value는 읽기 전용입니다. 설정하려면 set()을 사용하십시오.

버전 3.8에서 변경: samesite 어트리뷰트에 대한 지원이 추가되었습니다.

Morsel.value

쿠키의 값.

Morsel.coded_value

쿠키의 인코딩된 값 — 이것을 전송해야 합니다.

Morsel.key

쿠키의 이름.

Morsel.set(key, value, coded_value)

key, value 및 coded_value 어트리뷰트를 설정합니다.

Morsel.isReservedKey(K)

K가 Morsel의 키 집합의 구성원인지를 판단합니다.

Morsel.output(attrs=None, header='Set-Cookie:')

HTTP 헤더로 보내기에 적합한, Morsel의 문자열 표현을 반환합니다. 기본적으로, attrs가 주어지지 않는 한, 모든 어트리뷰트가 포함됩니다. 주어지면 사용할 어트리뷰트 리스트여야 합니다. header는 기본적으로 "Set-Cookie:"입니다.

Morsel.js_output(attrs=None)

자바스크립트를 지원하는 브라우저에서 실행될 때, HTTP 헤더가 전송된 것처럼 작동하는, 삽입 가능한 자바스크립트 코드 조각을 반환합니다.

attrs의 의미는 output()과 같습니다.

Morsel.OutputString(attrs=None)

둘러싸는 HTTP나 자바스크립트 없이 Morsel을 표현하는 문자열을 반환합니다.

attrs의 의미는 output()과 같습니다.

Morsel.update(values)

Morsel 딕셔너리의 값을 닥셔너리 values의 값으로 갱신합니다. values 딕셔너리의 키 중 하나라도 유효한 RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 어트리뷰트가 아니면 에러를 발생시킵니다.

버전 3.5에서 변경: 유효하지 않은 키에 대해서 에러가 발생합니다.

Morsel.copy(value)

Morsel 객체의 얕은 복사본을 반환합니다.

버전 3.5에서 변경: 딕셔너리 대신 Morsel 객체를 반환합니다.

Morsel.setdefault(key, value=None)

key가 유효한 RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 어트리뷰트가 아니면 에러를 발생시킵니다. 그렇지 않으면, dict.setdefault()와 같이 동작합니다.

예제

다음 예제는 http.cookies 모듈을 사용하는 방법을 보여줍니다.

>>> from http import cookies
>>> C = cookies.SimpleCookie()
>>> C["fig"] = "newton"
>>> C["sugar"] = "wafer"
>>> print(C) # generate HTTP headers
Set-Cookie: fig=newton
Set-Cookie: sugar=wafer
>>> print(C.output()) # same thing
Set-Cookie: fig=newton
Set-Cookie: sugar=wafer
>>> C = cookies.SimpleCookie()
>>> C["rocky"] = "road"
>>> C["rocky"]["path"] = "/cookie"
>>> print(C.output(header="Cookie:"))
Cookie: rocky=road; Path=/cookie
>>> print(C.output(attrs=[], header="Cookie:"))
Cookie: rocky=road
>>> C = cookies.SimpleCookie()
>>> C.load("chips=ahoy; vienna=finger") # load from a string (HTTP header)
>>> print(C)
Set-Cookie: chips=ahoy
Set-Cookie: vienna=finger
>>> C = cookies.SimpleCookie()
>>> C.load('keebler="E=everybody; L=\\"Loves\\"; fudge=\\012;";')
>>> print(C)
Set-Cookie: keebler="E=everybody; L=\"Loves\"; fudge=\012;"
>>> C = cookies.SimpleCookie()
>>> C["oreo"] = "doublestuff"
>>> C["oreo"]["path"] = "/"
>>> print(C)
Set-Cookie: oreo=doublestuff; Path=/
>>> C = cookies.SimpleCookie()
>>> C["twix"] = "none for you"
>>> C["twix"].value
'none for you'
>>> C = cookies.SimpleCookie()
>>> C["number"] = 7 # equivalent to C["number"] = str(7)
>>> C["string"] = "seven"
>>> C["number"].value
'7'
>>> C["string"].value
'seven'
>>> print(C)
Set-Cookie: number=7
Set-Cookie: string=seven

http.cookiejar — Cookie handling for HTTP clients

소스 코드: Lib/http/cookiejar.py [https://github.com/python/cpython/tree/main/Lib/http/cookiejar.py]

http.cookiejar 모듈은 HTTP 쿠키의 자동 처리를 위한 클래스를 정의합니다. 웹 서버의 HTTP 응답으로 클라이언트 시스템에 설정된 후, 이후의 HTTP 요청에서 서버로 반환되는 작은 데이터 조각 – 쿠키(cookies) – 을 요구하는 웹 사이트에 액세스하는 데 유용합니다.

Both the regular Netscape cookie protocol and the protocol defined by RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] are handled. RFC 2965 handling is switched off by default. RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] cookies are parsed as Netscape cookies and subsequently treated either as Netscape or RFC 2965 cookies according to the ‘policy’ in effect. Note that the great majority of cookies on the internet are Netscape cookies. http.cookiejar attempts to follow the de-facto Netscape cookie protocol (which differs substantially from that set out in the original Netscape specification), including taking note of the max-age and port cookie-attributes introduced with RFC 2965.

참고

Set-Cookie와 Set-Cookie2 헤더에서 발견되는 다양한 이름 붙은 파라미터(예를 들어, domain과 expires)는 통상적으로 어트리뷰트(attributes)로 지칭됩니다. 파이썬 어트리뷰트와 구별하기 위해, 이 모듈의 설명서는 쿠키 어트리뷰트(cookie-attribute)라는 용어를 대신 사용합니다.

모듈은 다음 예외를 정의합니다:

exception http.cookiejar.LoadError

FileCookieJar 인스턴스는 파일에서 쿠키를 로드하지 못하면 이 예외를 발생시킵니다. LoadError는 OSError의 서브 클래스입니다.

버전 3.3에서 변경: LoadError used to be a subtype of IOError, which is now an alias of OSError.

다음과 같은 클래스가 제공됩니다:

class http.cookiejar.CookieJar(policy=None)

policy는 CookiePolicy 인터페이스를 구현하는 객체입니다.

CookieJar 클래스는 HTTP 쿠키를 저장합니다. HTTP 요청에서 쿠키를 추출하고, HTTP 응답으로 반환합니다. 필요하면 CookieJar 인스턴스는 포함된 쿠키를 자동으로 만료합니다. 서브 클래스는 파일이나 데이터베이스에서 쿠키를 저장하고 검색하는 역할도 합니다.

class http.cookiejar.FileCookieJar(filename=None, delayload=None, policy=None)

policy는 CookiePolicy 인터페이스를 구현하는 객체입니다. 다른 인자에 대해서는, 해당 어트리뷰트의 설명서를 참조하십시오.

디스크의 파일에서 쿠키를 로드하고 아마도 파일에 쿠키를 저장할 수 있는 CookieJar. load()나 revert() 메서드가 호출될 때까지 이름이 지정된 파일에서 쿠키가 로드되지 않습니다. 이 클래스의 서브 클래스는 FileCookieJar 서브 클래스와 웹 브라우저와의 협력 섹션에 설명되어 있습니다.

This should not be initialized directly – use its subclasses below instead.

버전 3.8에서 변경: filename 매개 변수는 경로류 객체를 지원합니다.

class http.cookiejar.CookiePolicy

이 클래스는 각 쿠키가 서버에서 수락되고 서버로 반환되어야 하는지를 결정하는 역할을 맡습니다.

class http.cookiejar.DefaultCookiePolicy(blocked_domains=None, allowed_domains=None, netscape=True, rfc2965=False, rfc2109_as_netscape=None, hide_cookie2=False, strict_domain=False, strict_rfc2965_unverifiable=True, strict_ns_unverifiable=False, strict_ns_domain=DefaultCookiePolicy.DomainLiberal, strict_ns_set_initial_dollar=False, strict_ns_set_path=False, secure_protocols=('https', 'wss'))

생성자 인자는 키워드 인자로만 전달해야 합니다. blocked_domains는 쿠키를 수락하지도 쿠키를 반환하지도 않을 도메인 이름의 시퀀스입니다. allowed_domains가 None이 아니면, 이것이 쿠키를 수락하고 반환하는 유일한 도메인의 시퀀스입니다. secure_protocols는 보안 쿠키를 추가 할 수 있는 프로토콜의 시퀀스입니다. 기본적으로 https와 wss(보안 웹 소켓)는 보안 프로토콜로 간주합니다. 다른 모든 인자는, CookiePolicy와 DefaultCookiePolicy 객체에 대한 설명서를 참조하십시오.

DefaultCookiePolicy는 Netscape와 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 쿠키를 위한 표준 수락/거부 규칙을 구현합니다. 기본적으로, RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 쿠키(즉 version 쿠키 어트리뷰트가 1인 Set-Cookie 헤더로 수신된 쿠키)는 RFC 2965 규칙에 따라 처리됩니다. 그러나, RFC 2965 처리가 꺼져 있거나 rfc2109_as_netscape가 True이면, Cookie 인스턴스의 version 어트리뷰트를 0으로 설정하여, CookieJar 인스턴스에서 RFC 2109 쿠키를 Netscape 쿠키로 ‘다운 그레이드’ 합니다. DefaultCookiePolicy는 정책을 미세 조정할 수 있는 매개 변수도 제공합니다.

class http.cookiejar.Cookie

이 클래스는 Netscape, RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 및 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 쿠키를 나타냅니다. http.cookiejar 사용자가 스스로 Cookie 인스턴스를 만들 것으로 기대하지 않습니다. 대신, 필요하면, CookieJar 인스턴스에서 make_cookies()를 호출하십시오.

더 보기

모듈 urllib.request

자동 쿠키 처리가 지원되는 URL 열기.

모듈 http.cookies

HTTP 쿠키 클래스, 주로 서버 측 코드에 유용합니다. http.cookiejar와 http.cookies 모듈은 서로 의존하지 않습니다.

https://curl.se/rfc/cookie_spec.html

원래 Netscape 쿠키 프로토콜의 명세. 이것이 여전히 지배적인 프로토콜이지만, 모든 주요 브라우저(및 http.cookiejar)에 의해 구현된 ‘Netscape 쿠키 프로토콜’은 사라져가는 cookie_spec.html에서 스케치 된 것과의 유사성을 담고 있을 뿐입니다.

RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] - HTTP 상태 관리 메커니즘

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]로 개정되었습니다. version=1 인 Set-Cookie를 사용합니다.

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] - HTTP 상태 관리 메커니즘

버그가 수정된 Netscape 프로토콜. Set-Cookie 대신 Set-Cookie2를 사용합니다. 널리 사용되지 않습니다.

https://kristol.org/cookie/errata.html

완료되지 않은 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]의 정오표.

RFC 2964 [https://datatracker.ietf.org/doc/html/rfc2964.html] - HTTP 상태 관리 사용

CookieJar와 FileCookieJar 객체

CookieJar 객체는 포함된 Cookie 객체를 이터레이트 하기 위한 이터레이터 프로토콜을 지원합니다.

CookieJar에는 다음과 같은 메서드가 있습니다:

CookieJar.add_cookie_header(request)

request에 올바른 Cookie 헤더를 추가합니다.

정책이 허용하면 (즉, CookieJar의 CookiePolicy 인스턴스의 rfc2965와 hide_cookie2 어트리뷰트가 각각 참과 거짓이면), Cookie2 헤더도 적절한 경우 추가됩니다.

The request object (usually a urllib.request.Request instance) must support the methods get_full_url(), has_header(), get_header(), header_items(), add_unredirected_header() and the attributes host, type, unverifiable and origin_req_host as documented by urllib.request.

버전 3.3에서 변경: request 객체에는 origin_req_host 어트리뷰트가 필요합니다. 폐지된 메서드 get_origin_req_host()에 대한 의존성이 제거되었습니다.

CookieJar.extract_cookies(response, request)

HTTP response에서 쿠키를 추출하여 정책이 허용하면 CookieJar에 저장합니다.

CookieJar는 response 인자에서 수락할 수 있는 Set-Cookie와 Set-Cookie2 헤더를 찾고, 쿠키를 적절하게 저장합니다 (CookiePolicy.set_ok() 메서드의 승인에 따라).

response 객체(일반적으로 urllib.request.urlopen() 호출의 결과, 또는 유사한 것)는 email.message.Message 인스턴스를 반환하는 info() 메서드를 지원해야 합니다.

The request object (usually a urllib.request.Request instance) must support the method get_full_url() and the attributes host, unverifiable and origin_req_host, as documented by urllib.request. The request is used to set default values for cookie-attributes as well as for checking that the cookie is allowed to be set.

버전 3.3에서 변경: request 객체에는 origin_req_host 어트리뷰트가 필요합니다. 폐지된 메서드 get_origin_req_host()에 대한 의존성이 제거되었습니다.

CookieJar.set_policy(policy)

사용할 CookiePolicy 인스턴스를 설정합니다.

CookieJar.make_cookies(response, request)

response 객체에서 추출한 Cookie 객체의 시퀀스를 반환합니다.

response와 request 인자에 필요한 인터페이스는 extract_cookies() 설명서를 참조하십시오.

CookieJar.set_cookie_if_ok(cookie, request)

정책이 그래도 좋다고 한다면 Cookie를 설정합니다.

CookieJar.set_cookie(cookie)

설정할 수 있는지 정책을 확인하지 않고, Cookie를 설정합니다.

CookieJar.clear([domain[, path[, name]]])

일부 쿠키를 지웁니다.

인자 없이 호출되면, 모든 쿠키를 지웁니다. 단일 인자가 제공되면, 해당 domain에 속하는 쿠키만 제거됩니다. 두 개의 인자가 제공되면, 지정된 domain과 URL path에 속하는 쿠키가 제거됩니다. 세 개의 인자가 제공되면, 지정된 domain, path 및 name을 갖는 쿠키가 제거됩니다.

일치하는 쿠키가 없으면 KeyError를 발생시킵니다.

CookieJar.clear_session_cookies()

모든 세션 쿠키를 폐기합니다.

실제 discard 어트리뷰트를 갖는 모든 쿠키를 폐기합니다 (보통 max-age나 expires 쿠키 어트리뷰트가 없기 때문에, 혹은 명시적인 discard 쿠키 어트리뷰트). 대화식 브라우저의 경우, 세션의 끝은 일반적으로 브라우저 창을 닫는 것에 해당합니다.

save() 메서드는 참값의 ignore_discard 인자를 전달하여 다르게 요청하지 않는 한 세션 쿠키를 저장하지 않음에 유의하십시오.

FileCookieJar는 다음과 같은 추가 메서드를 구현합니다:

FileCookieJar.save(filename=None, ignore_discard=False, ignore_expires=False)

쿠키를 파일에 저장합니다.

이 베이스 클래스는 NotImplementedError를 발생시킵니다. 서브 클래스는 이 메서드를 구현하지 않은 채로 둘 수 있습니다.

filename은 쿠키를 저장할 파일의 이름입니다. filename을 지정하지 않으면, self.filename이 사용됩니다 (이것의 기본값은 생성자에게 전달된 값입니다, 있다면); self.filename이 None이면 ValueError가 발생합니다.

ignore_discard: 폐기되는 것으로 설정된 쿠키도 저장합니다. ignore_expires: 만료된 쿠키도 저장합니다

파일이 이미 존재하면, 파일을 덮어써서, 파일에 포함된 모든 쿠키를 지웁니다. 저장된 쿠키는 나중에 load()나 revert() 메서드를 사용하여 복원할 수 있습니다.

FileCookieJar.load(filename=None, ignore_discard=False, ignore_expires=False)

파일에서 쿠키를 로드합니다.

새로 로드한 쿠키가 덮어쓰지 않는 한 오래된 쿠키는 유지됩니다.

인자는 save()와 같습니다.

명명된 파일은 클래스가 이해하는 형식이어야 하고, 그렇지 않으면 LoadError가 발생합니다. 또한, 예를 들어 파일이 존재하지 않으면, OSError가 발생할 수 있습니다.

버전 3.3에서 변경: IOError가 발생했었지만, 이제는 OSError의 별칭입니다.

FileCookieJar.revert(filename=None, ignore_discard=False, ignore_expires=False)

모든 쿠키를 지우고 저장된 파일에서 쿠키를 다시 로드합니다.

revert()는 load()와 같은 예외를 발생시킬 수 있습니다. 실패가 일어나면, 객체 상태는 변경되지 않습니다.

FileCookieJar 인스턴스에는 다음과 같은 공용 어트리뷰트가 있습니다:

FileCookieJar.filename

쿠키를 보관할 기본 파일의 파일명. 이 어트리뷰트는 대입할 수 있습니다.

FileCookieJar.delayload

참이면, 디스크에서 쿠키를 천천히(lazily) 로드합니다. 이 어트리뷰트는 대입하지 않아야 합니다. (디스크의 쿠키가 변경되지 않는 한) 성능에만 영향을 미칠 뿐 동작을 바꾸지는 않기 때문에, 이것은 힌트일 뿐입니다. CookieJar 객체는 이를 무시할 수 있습니다. 표준 라이브러리에 포함된 FileCookieJar 클래스는 아무것도 쿠키를 천천히 로드하지 않습니다.

FileCookieJar 서브 클래스와 웹 브라우저와의 협력

다음 CookieJar 서브 클래스는 읽기와 쓰기를 위해 제공됩니다.

class http.cookiejar.MozillaCookieJar(filename=None, delayload=None, policy=None)

A FileCookieJar that can load from and save cookies to disk in the Mozilla cookies.txt file format (which is also used by curl and the Lynx and Netscape browsers).

참고

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 쿠키에 대한 정보와, port 같은 최신이나 비표준 쿠키 어트리뷰트에 대한 정보가 손실됩니다.

경고

손실/손상이 불편한 쿠키가 있다면 저장하기 전에 쿠키를 백업하십시오 (로드/저장 왕복으로 인해 파일이 약간 변경될 수 있는 미묘한 부분이 있습니다).

또한 Mozilla가 실행되는 동안 저장된 쿠키는 Mozilla에 의해 방해를 받음에 유의하십시오.

class http.cookiejar.LWPCookieJar(filename=None, delayload=None, policy=None)

libwww-perl 라이브러리의 Set-Cookie3 파일 형식과 호환되는 형식으로 쿠키를 디스크에서 로드하고 저장할 수 있는 FileCookieJar. 사람이 읽을 수 있는 파일에 쿠키를 저장하려는 경우에 편리합니다.

버전 3.8에서 변경: filename 매개 변수는 경로류 객체를 지원합니다.

CookiePolicy 객체

CookiePolicy 인터페이스를 구현하는 객체에는 다음과 같은 메서드가 있습니다:

CookiePolicy.set_ok(cookie, request)

서버에서 쿠키를 수락해야 하는지를 나타내는 불리언 값을 반환합니다.

cookie는 Cookie 인스턴스입니다. request는 CookieJar.extract_cookies() 설명서에서 정의한 인터페이스를 구현하는 객체입니다.

CookiePolicy.return_ok(cookie, request)

쿠키를 서버로 반환해야 하는지를 나타내는 불리언 값을 반환합니다.

cookie는 Cookie 인스턴스입니다. request는 CookieJar.add_cookie_header() 설명서에서 정의한 인터페이스를 구현하는 객체입니다.

CookiePolicy.domain_return_ok(domain, request)

주어진 쿠키 도메인(domain)에서, 쿠키를 반환하지 않아야 하면 False를 반환합니다.

이 메서드는 최적화입니다. 특정 도메인을 가진 모든 쿠키를 검사할 필요(많은 파일을 읽는 것을 수반합니다)를 제거합니다. domain_return_ok()와 path_return_ok()에서 참을 반환하면 모든 작업이 return_ok()로 넘어갑니다.

쿠키 도메인에 대해 domain_return_ok()가 참을 반환하면, 쿠키 경로에 대해 path_return_ok()가 호출됩니다. 그렇지 않으면, 해당 쿠키 도메인에 대해 path_return_ok()와 return_ok()가 호출되지 않습니다. path_return_ok()가 참을 반환하면, return_ok()가 Cookie 객체 자체로 호출되어 전체 검사를 수행합니다. 그렇지 않으면, 해당 쿠키 경로에 대해 return_ok()가 호출되지 않습니다.

domain_return_ok()는 request 도메인뿐만 아니라 모든 cookie 도메인에 대해 호출됨에 유의하십시오. 예를 들어, 요청 도메인이 "www.example.com"이면 함수는 ".example.com"과 "www.example.com" 모두에 대해 호출될 수 있습니다. path_return_ok()도 마찬가지입니다.

request 인자는 return_ok()에 대해 설명된 대로입니다.

CookiePolicy.path_return_ok(path, request)

주어진 쿠키 경로에 대해, 쿠키를 반환하지 않아야 하면 False를 반환합니다.

domain_return_ok() 설명서를 참조하십시오.

위의 메서드를 구현하는 것 외에도, CookiePolicy 인터페이스의 구현은 어떤 프로토콜을 어떻게 사용해야 하는지를 나타내는 다음 어트리뷰트도 제공해야 합니다. 이러한 모든 어트리뷰트는 대입할 수 있습니다.

CookiePolicy.netscape

Netscape 프로토콜을 구현합니다.

CookiePolicy.rfc2965

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 프로토콜을 구현합니다.

CookiePolicy.hide_cookie2

요청에 Cookie2 헤더를 추가하지 않습니다 (이 헤더가 있으면 서버에게 우리가 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 쿠키를 이해하고 있음을 알립니다).

CookiePolicy 클래스를 정의하는 가장 유용한 방법은 DefaultCookiePolicy 에서 서브 클래싱하고 위의 메서드 중 일부나 전부를 재정의하는 것입니다. CookiePolicy 자체는 모든 쿠키를 설정하고 수신하도록 허용하는 ‘널 정책’으로 사용될 수 있습니다 (이 정책이 그리 유용하지는 않을 것입니다).

DefaultCookiePolicy 객체

쿠키 수락과 반환에 대한 표준 규칙을 구현합니다.

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]와 Netscape 쿠키를 모두 다룹니다. RFC 2965 처리는 기본적으로 꺼져있습니다.

자체 정책을 제공하는 가장 쉬운 방법은 이 클래스를 재정의하고 자체 검사를 추가하기 전에 재정의된 구현에서 해당 메서드를 호출하는 것입니다:

import http.cookiejar
class MyCookiePolicy(http.cookiejar.DefaultCookiePolicy):
    def set_ok(self, cookie, request):
        if not http.cookiejar.DefaultCookiePolicy.set_ok(self, cookie, request):
            return False
        if i_dont_want_to_store_this_cookie(cookie):
            return False
        return True

CookiePolicy 인터페이스를 구현하는 데 필요한 기능 외에도, 이 클래스를 사용하면 도메인이 쿠키를 설정하고 수신하는 것을 차단하고 허락할 수 있도록 합니다. 또한 다소 느슨한 Netscape 프로토콜 규칙을 약간 강화할 수 있는 몇 가지 엄격성 스위치가 있습니다 (일부 양성 쿠키를 차단하는 대가를 치르면서).

A domain blocklist and allowlist is provided (both off by default). Only domains not in the blocklist and present in the allowlist (if the allowlist is active) participate in cookie setting and returning. Use the blocked_domains constructor argument, and blocked_domains() and set_blocked_domains() methods (and the corresponding argument and methods for allowed_domains). If you set an allowlist, you can turn it off again by setting it to None.

Domains in block or allow lists that do not start with a dot must equal the cookie domain to be matched. For example, "example.com" matches a blocklist entry of "example.com", but "www.example.com" does not. Domains that do start with a dot are matched by more specific domains too. For example, both "www.example.com" and "www.coyote.example.com" match ".example.com" (but "example.com" itself does not). IP addresses are an exception, and must match exactly. For example, if blocked_domains contains "192.168.1.2" and ".168.1.2", 192.168.1.2 is blocked, but 193.168.1.2 is not.

DefaultCookiePolicy는 다음과 같은 추가 메서드를 구현합니다:

DefaultCookiePolicy.blocked_domains()

차단된 도메인 시퀀스를 반환합니다 (튜플로).

DefaultCookiePolicy.set_blocked_domains(blocked_domains)

차단된 도메인 시퀀스를 설정합니다.

DefaultCookiePolicy.is_blocked(domain)

Return True if domain is on the blocklist for setting or receiving cookies.

DefaultCookiePolicy.allowed_domains()

None, 또는 수락 도메인 시퀀스를 반환합니다 (튜플).

DefaultCookiePolicy.set_allowed_domains(allowed_domains)

수락 도메인 시퀀스, 또는 None을 설정합니다.

DefaultCookiePolicy.is_not_allowed(domain)

Return True if domain is not on the allowlist for setting or receiving cookies.

DefaultCookiePolicy 인스턴스에는 다음과 같은 어트리뷰트가 있습니다. 이 어트리뷰트들은 모두 같은 이름의 생성자 인자로 초기화되며, 모두 대입할 수 있습니다.

DefaultCookiePolicy.rfc2109_as_netscape

참이면, CookieJar 인스턴스가 Cookie 인스턴스의 version 쿠키 어트리뷰트를 0으로 설정하여 RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 쿠키(즉, Set-Cookie 헤더에서 수신된 version 쿠키 어트리뷰트가 1인 쿠키)를 Netscape 쿠키로 다운 그레이드하도록 요청합니다. 기본값은 None입니다, 이 경우 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 처리가 꺼졌을 때만 RFC 2109 쿠키가 다운 그레이드됩니다. 따라서, RFC 2109 쿠키는 기본적으로 다운 그레이드됩니다.

일반 엄격성 스위치:

DefaultCookiePolicy.strict_domain

사이트가 .co.uk, .gov.uk, .co.nz 등의 국가 코드 최상위 도메인으로 2개의 구성 요소 도메인을 설정하는 것을 수락하지 않습니다. 이것은 완벽하지는 않으며 작동하지 않을 수도 있습니다!

RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 프로토콜 엄격성 스위치:

DefaultCookiePolicy.strict_rfc2965_unverifiable

확인할 수 없는 트랜잭션(unverifiable transactions)에 대한 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 규칙을 따릅니다 (일반적으로 확인할 수 없는 트랜잭션은 다른 사이트에서 호스팅 되는 이미지에 대한 리디렉션이나 요청으로 인한 결과입니다). 이것이 거짓이면, 확인 가능성에 기초하여 쿠키가 차단되지 않습니다.

넷스케이프 프로토콜 엄격성 스위치:

DefaultCookiePolicy.strict_ns_unverifiable

Netscape 쿠키에도 확인할 수 없는 트랜잭션에 대한 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 규칙을 적용합니다.

DefaultCookiePolicy.strict_ns_domain

Netscape 쿠키에 대한 도메인 일치 규칙이 얼마나 엄격한지를 나타내는 플래그. 허용 가능한 값은 아래를 참조하십시오.

DefaultCookiePolicy.strict_ns_set_initial_dollar

이름이 '$'로 시작하는 Set-Cookie: 헤더의 쿠키를 무시합니다.

DefaultCookiePolicy.strict_ns_set_path

경로가 요청 URI와 경로 일치하지 않는 쿠키 설정을 수락하지 않습니다.

strict_ns_domain은 플래그 모음입니다. 그 값은 함께 or 하여 구성됩니다 (예를 들어, DomainStrictNoDots|DomainStrictNonDomain 은 두 플래그가 설정됨을 의미합니다).

DefaultCookiePolicy.DomainStrictNoDots

쿠키를 설정할 때, ‘호스트 접두사’에는 점이 없어야 합니다 (예를 들어 www.foo에 점이 있어서, www.foo.bar.com이 .bar.com에 대한 쿠키를 설정할 수 없습니다).

DefaultCookiePolicy.DomainStrictNonDomain

domain 쿠키 어트리뷰트를 명시적으로 지정하지 않은 쿠키는 쿠키를 설정한 도메인과 같은 도메인으로만 반환될 수 있습니다 (예를 들어 spam.example.com으로는 domain 쿠키 어트리뷰트가 없는 example.com의 쿠키를 반환하지 않습니다).

DefaultCookiePolicy.DomainRFC2965Match

쿠키를 설정할 때, 전체 RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 도메인 일치가 필요합니다.

편의를 위해 다음 어트리뷰트가 제공되며, 위 플래그의 가장 유용한 조합입니다:

DefaultCookiePolicy.DomainLiberal

0과 동등합니다 (즉, 위의 모든 Netscape 도메인 엄격성 플래그가 꺼집니다).

DefaultCookiePolicy.DomainStrict

DomainStrictNoDots|DomainStrictNonDomain 과 동등합니다.

Cookie 객체

Cookie 인스턴스는 다양한 쿠키 표준에 지정된 표준 쿠키 어트리뷰트에 대략 상응하는 파이썬 어트리뷰트를 갖습니다. 기본값을 지정하기 위한 복잡한 규칙이 있고, max-age와 expires 쿠키 어트리뷰트가 동등한 정보를 포함하고, RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 쿠키가 버전 1에서 버전 0 (Netscape) 쿠키로 http.cookiejar에 의해 ‘다운 그레이드’ 될 수 있기 때문에 대응은 일대일이 아닙니다.

CookiePolicy 메서드에서의 드문 경우를 제외하고 이러한 어트리뷰트에 대입할 필요는 없습니다. 이 클래스는 내부 일관성을 강요하지 않기 때문에, 그렇게 한다면 무엇을 하고 있는지 알아야 합니다.

Cookie.version

정수나 None. Netscape 쿠키는 version 0을 갖습니다. RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html]와 RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 쿠키는 1의 version 쿠키 어트리뷰트를 갖습니다. 그러나, http.cookiejar는 RFC 2109 쿠키를 Netscape 쿠키로 ‘다운 그레이드’할 수 있으며, 이 경우 version은 0입니다.

Cookie.name

쿠키 이름 (문자열).

Cookie.value

쿠키값 (문자열), 또는 None.

Cookie.port

포트나 포트 집합을 나타내는 문자열 (예를 들어 ‘80’이나 ‘80,8080’), 또는 None.

Cookie.domain

Cookie domain (a string).

Cookie.path

쿠키 경로 (문자열, 예를 들어 '/acme/rocket_launchers').

Cookie.secure

쿠키가 보안 연결을 통해서만 반환되어야 하면 True.

Cookie.expires

에포크 이후의 초 단위 정수 만료 날짜, 또는 None. is_expired() 메서드도 참조하십시오.

Cookie.discard

세션 쿠키이면 True.

Cookie.comment

이 쿠키의 기능을 설명하는 서버의 문자열 주석, 또는 None.

Cookie.comment_url

이 쿠키의 기능을 설명하는 서버의 주석에 대한 URL 링크, 또는 None.

Cookie.rfc2109

이 쿠키가 RFC 2109 [https://datatracker.ietf.org/doc/html/rfc2109.html] 쿠키로 수신되었으면 (즉 쿠키가 Set-Cookie 헤더로 도착하고, 해당 헤더의 Version 쿠키 어트리뷰트 값이 1인 경우) True. http.cookiejar가 RFC 2109 쿠키를 Netscape 쿠키로 ‘다운 그레이드’할 수 있기 때문에 이 어트리뷰트가 제공됩니다. 이 경우 version은 0입니다.

Cookie.port_specified

서버가 (Set-Cookie / Set-Cookie2 헤더에서) 포트나 포트 집합을 명시적으로 지정했으면 True.

Cookie.domain_specified

서버가 도메인을 명시적으로 지정했으면 True.

Cookie.domain_initial_dot

서버에서 명시적으로 지정한 도메인이 점('.')으로 시작하면 True.

쿠키에는 비표준 쿠키 어트리뷰트가 추가로 있을 수 있습니다. 다음 메서드를 사용하여 액세스 할 수 있습니다:

Cookie.has_nonstandard_attr(name)

쿠키에 지정된 이름의 쿠키 어트리뷰트가 있으면 True를 반환합니다.

Cookie.get_nonstandard_attr(name, default=None)

쿠키에 지정된 이름의 쿠키 어트리뷰트가 있으면, 그 값을 반환합니다. 그렇지 않으면 default를 반환합니다.

Cookie.set_nonstandard_attr(name, value)

지정된 이름의 쿠키 어트리뷰트의 값을 설정합니다.

Cookie 클래스는 다음 메서드도 정의합니다:

Cookie.is_expired(now=None)

쿠키에 대해 서버가 만료해야 한다고 요청한 시간이 지났으면 True. now가 제공되면 (에포크 이후의 초로), 쿠키가 지정된 시간에 만료되는지를 반환합니다.

예

첫 번째 예는 http.cookiejar의 가장 일반적인 사용법을 보여줍니다:

import http.cookiejar, urllib.request
cj = http.cookiejar.CookieJar()
opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
r = opener.open("http://example.com/")

이 예는 Netscape, Mozilla 또는 Lynx 쿠키를 사용하여 URL을 여는 방법을 보여줍니다 (쿠키 파일의 위치에 대해서는 유닉스/Netscape 규칙을 가정합니다):

import os, http.cookiejar, urllib.request
cj = http.cookiejar.MozillaCookieJar()
cj.load(os.path.join(os.path.expanduser("~"), ".netscape", "cookies.txt"))
opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
r = opener.open("http://example.com/")

다음 예는 DefaultCookiePolicy 의 사용법을 보여줍니다. RFC 2965 [https://datatracker.ietf.org/doc/html/rfc2965.html] 쿠키를 켜고, Netscape 쿠키를 설정하고 반환할 때 도메인에 대해 더욱 엄격하며, 일부 도메인이 쿠키를 설정하거나 쿠키를 반환하지 못하도록 차단합니다:

import urllib.request
from http.cookiejar import CookieJar, DefaultCookiePolicy
policy = DefaultCookiePolicy(
    rfc2965=True, strict_ns_domain=Policy.DomainStrict,
    blocked_domains=["ads.net", ".ads.net"])
cj = CookieJar(policy)
opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
r = opener.open("http://example.com/")

xmlrpc — XMLRPC server and client modules

XML-RPC는 HTTP를 트랜스포트로 사용해서 전달되는 XML을 사용하는 원격 프로시저 호출 방법입니다. 이를 통해, 클라이언트는 원격 서버(서버는 URI로 지정됩니다)의 매개 변수가 있는 메서드를 호출하고 구조화된 데이터를 받을 수 있습니다.

xmlrpc는 XML-RPC를 구현하는 서버와 클라이언트 모듈을 모아둔 패키지입니다. 모듈은 다음과 같습니다:

xmlrpc.client

xmlrpc.server

xmlrpc.client — XML-RPC client access

소스 코드: Lib/xmlrpc/client.py [https://github.com/python/cpython/tree/main/Lib/xmlrpc/client.py]

XML-RPC는 HTTP(S)를 통해 전달된 XML을 트랜스포트로 사용하는 원격 프로시저 호출(Remote Procedure Call) 방법입니다. 이를 통해, 클라이언트는 원격 서버에서 매개 변수를 사용하여 메서드를 호출하고 (서버는 URI로 이름이 지정됩니다) 구조화된 데이터를 돌려받을 수 있습니다. 이 모듈은 XML-RPC 클라이언트 코드 작성을 지원합니다; 적합한 파이썬 객체와 전송 회선 상의 XML 간 변환의 모든 세부 사항을 처리합니다.

경고

xmlrpc.client 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 하면 XML 취약점을 참조하십시오.

버전 3.5에서 변경: HTTPS URI의 경우, xmlrpc.client는 이제 기본적으로 필요한 모든 인증서와 호스트명 확인을 수행합니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

class xmlrpc.client.ServerProxy(uri, transport=None, encoding=None, verbose=False, allow_none=False, use_datetime=False, use_builtin_types=False, *, headers=(), context=None)

ServerProxy 인스턴스는 원격 XML-RPC 서버와의 통신을 관리하는 객체입니다. 필수적인 첫 번째 인자는 URI(Uniform Resource Indicator)이며 일반적으로 서버의 URL입니다. 선택적인 두 번째 인자는 트랜스포트 팩토리 인스턴스입니다; 기본적으로 https: URL의 경우는 내부 SafeTransport 인스턴스이고 그렇지 않으면 내부 HTTP Transport 인스턴스입니다. 선택적 세 번째 인자는 인코딩이며, 기본적으로 UTF-8입니다. 선택적 네 번째 인자는 디버깅 플래그입니다.

The following parameters govern the use of the returned proxy instance. If allow_none is true, the Python constant None will be translated into XML; the default behaviour is for None to raise a TypeError. This is a commonly used extension to the XML-RPC specification, but isn’t supported by all clients and servers; see http://ontosys.com/xml-rpc/extensions.php [https://web.archive.org/web/20130120074804/http://ontosys.com/xml-rpc/extensions.php] for a description. The use_builtin_types flag can be used to cause date/time values to be presented as datetime.datetime objects and binary data to be presented as bytes objects; this flag is false by default. datetime.datetime, bytes and bytearray objects may be passed to calls. The headers parameter is an optional sequence of HTTP headers to send with each request, expressed as a sequence of 2-tuples representing the header name and value. (e.g. [('Header-Name', 'value')]). The obsolete use_datetime flag is similar to use_builtin_types but it applies only to date/time values.

버전 3.3에서 변경: use_builtin_types 플래그가 추가되었습니다.

버전 3.8에서 변경: headers 매개 변수가 추가되었습니다.

HTTP와 HTTPS 트랜스포트는 모두 HTTP 기본 인증(Basic Authentication)을 위한 URL 구문 확장을 지원합니다: http://user:pass@host:port/path. user:pass 부분은 HTTP ‘Authorization’ 헤더로 base64 인코딩되고, XML-RPC 메서드를 호출할 때 연결 프로세스의 일부로 원격 서버로 전송됩니다. 원격 서버가 기본 인증 사용자와 비밀번호를 요구할 때만 이를 사용해야 합니다. HTTPS URL이 제공되면, context는 ssl.SSLContext 일 수 있고 하부 HTTPS 연결의 SSL 설정을 구성합니다.

반환된 인스턴스는 원격 서버에서 해당 RPC 호출을 호출하는 데 사용할 수 있는 메서드가 있는 프락시 객체입니다. 원격 서버가 인트로스펙션(introspection) API를 지원하면, 프락시를 사용하여 원격 서버에서 지원하는 메서드를 조회하고 (서비스 검색, service discovery) 다른 서버 관련 메타 데이터를 가져올 수 있습니다.

적합한 형(예를 들어 XML을 통해 마샬링 할 수 있는 형)에는 다음이 포함됩니다 (별도로 표시된 경우를 제외하고는 같은 파이썬 형으로 역마샬링 됩니다):

XML-RPC 형

파이썬 형

boolean

bool

int, i1, i2, i4, i8 또는 biginteger

-2147483648에서 2147483647 범위의 int. 값은 <int> 태그를 얻습니다.

double이나 float

float. 값은 <double> 태그를 얻습니다.

string

str

array

적합한 요소를 포함하는 list나 tuple. 배열은 리스트로 반환됩니다.

struct

dict. 키는 문자열이어야 하며, 값은 적합한 형일 수 있습니다. 사용자 정의 클래스의 객체를 전달할 수 있습니다; __dict__ 어트리뷰트만 전송됩니다.

dateTime.iso8601

DateTime이나 datetime.datetime. 반환되는 형은 use_builtin_types와 use_datetime 플래그 값에 따라 다릅니다.

base64

Binary, bytes 또는 bytearray. 반환되는 형은 use_builtin_types 플래그의 값에 따라 다릅니다.

nil

None 상수. allow_none이 참일 때만 전달이 허용됩니다.

bigdecimal

decimal.Decimal. 반환되는 형 전용.

이것이 XML-RPC가 지원하는 데이터형의 전체 집합입니다. 메서드 호출은 XML-RPC 서버 에러를 알리는 데 사용되는 특수 Fault 인스턴스나 HTTP/HTTPS 전송 계층의 에러를 알리는 데 사용되는 ProtocolError를 발생시킬 수도 있습니다. Fault와 ProtocolError는 모두 Error라는 베이스 클래스에서 파생됩니다. xmlrpc 클라이언트 모듈은 현재 내장형의 서브 클래스 인스턴스를 마샬링 하지 않음에 유의하십시오.

문자열을 전달할 때, <, > 및 &와 같은 XML에 특수한 문자는 자동으로 이스케이프 됩니다. 그러나, 0에서 31 사이의 ASCII 값을 가진 제어 문자(물론 탭, 줄 넘김 및 캐리지 리턴은 제외하고)와 같이 문자열에 XML에서 허용되지 않는 문자가 없도록 확인하는 것은 호출자의 책임입니다; 이렇게 하지 않으면 XML 형식이 잘못된 XML-RPC 요청이 발생합니다. XML-RPC를 통해 임의의 바이트열을 전달해야 하면, bytes나 bytearray 클래스 또는 아래 설명된 Binary 래퍼 클래스를 사용하십시오.

Server는 이전 버전과의 호환성을 위해 ServerProxy의 별칭으로 유지됩니다. 새 코드는 ServerProxy를 사용해야 합니다.

버전 3.5에서 변경: context 인자를 추가했습니다.

버전 3.6에서 변경: Added support of type tags with prefixes (e.g. ex:nil). Added support of unmarshalling additional types used by Apache XML-RPC implementation for numerics: i1, i2, i8, biginteger, float and bigdecimal. See https://ws.apache.org/xmlrpc/types.html for a description.

더 보기

XML-RPC HOWTO [https://tldp.org/HOWTO/XML-RPC-HOWTO/index.html]

여러 언어로 된 XML-RPC 연산과 클라이언트 소프트웨어에 대한 훌륭한 설명. XML-RPC 클라이언트 개발자가 알아야 할 거의 모든 것이 포함되어 있습니다.

XML-RPC Introspection [https://xmlrpc-c.sourceforge.io/introspection.html]

인트로스펙션을 위한 XML-RPC 프로토콜 확장을 설명합니다.

XML-RPC Specification [http://xmlrpc.scripting.com/spec.html]

공식 명세.

ServerProxy 객체

ServerProxy 인스턴스에는 XML-RPC 서버가 받아들이는 각 원격 프로시저 호출에 해당하는 메서드가 있습니다. 메서드를 호출하면 RPC를 수행하는데, 이름과 인자 서명 모두로 디스패치 됩니다 (예를 들어 같은 메서드 이름이 여러 인자 서명으로 오버로드 될 수 있습니다). RPC는 값을 반환하여 완료되는데, 값은 적합한 형으로 반환된 데이터이거나 에러를 나타내는 Fault나 ProtocolError 객체일 수 있습니다.

XML 인트로스팩션 API를 지원하는 서버는 예약된 system 어트리뷰트 밑에 그룹화된 몇 가지 공통 메서드를 지원합니다:

ServerProxy.system.listMethods()

이 메서드는 문자열 리스트를 반환하는데, XML-RPC 서버가 지원하는 각 (system이 아닌) 메서드마다 하나씩 제공됩니다.

ServerProxy.system.methodSignature(name)

이 메서드는 하나의 매개 변수를 취하는데, XML-RPC 서버에 의해 구현된 메서드의 이름입니다. 이 메서드에 대해 가능한 서명의 배열을 반환합니다. 서명은 형의 배열입니다. 이 형 중 첫 번째는 메서드의 반환형이고 나머지는 매개 변수입니다.

다중 서명(즉 오버로딩)이 허용되므로, 이 메서드는 하나가 아닌 서명의 리스트를 반환합니다.

서명 자체는 메서드가 기대하는 최상위 매개 변수로 제한됩니다. 예를 들어, 메서드가 구조체 배열 하나를 매개 변수로 기대하고, 문자열을 반환하면, 서명은 단순히 “string, array”입니다. 세 개의 정수를 기대하고 문자열을 반환하면, 서명은 “string, int, int, int”입니다.

메서드에 서명이 정의되지 않으면, 배열이 아닌 값이 반환됩니다. 파이썬에서 이것은 반환된 값의 형이 리스트 이외의 어떤 것이 됨을 의미합니다.

ServerProxy.system.methodHelp(name)

이 메서드는 하나의 매개 변수를 취하는데, XML-RPC 서버에 의해 구현된 메서드의 이름입니다. 해당 메서드의 사용법을 기술하는 설명서 문자열을 반환합니다. 이러한 문자열이 없으면, 빈 문자열이 반환됩니다. 설명서 문자열에 HTML 마크업이 포함될 수 있습니다.

버전 3.5에서 변경: ServerProxy 인스턴스는 하부 트랜스포트를 닫기 위한 컨텍스트 관리자 프로토콜을 지원합니다.

다음은 실제 예입니다. 서버 코드:

from xmlrpc.server import SimpleXMLRPCServer

def is_even(n):
    return n % 2 == 0

server = SimpleXMLRPCServer(("localhost", 8000))
print("Listening on port 8000...")
server.register_function(is_even, "is_even")
server.serve_forever()

이전 서버에 대한 클라이언트 코드:

import xmlrpc.client

with xmlrpc.client.ServerProxy("http://localhost:8000/") as proxy:
    print("3 is even: %s" % str(proxy.is_even(3)))
    print("100 is even: %s" % str(proxy.is_even(100)))

DateTime 객체

class xmlrpc.client.DateTime

이 클래스는 에포크(epoch) 이후의 초, 시간 튜플, ISO 8601 시간/날짜 문자열 또는 datetime.datetime으로 초기화될 수 있습니다. 주로 마샬링/역마샬링 코드 내부에서 사용하기 위해 지원되는, 다음과 같은 메서드가 있습니다:

decode(string)

인스턴스의 새 시간 값으로 문자열을 받아들입니다.

encode(out)

이 DateTime 항목의 XML-RPC 인코딩을 out 스트림 객체에 씁니다.

It also supports certain of Python’s built-in operators through rich comparison and __repr__() methods.

다음은 실제 예입니다. 서버 코드:

import datetime
from xmlrpc.server import SimpleXMLRPCServer
import xmlrpc.client

def today():
    today = datetime.datetime.today()
    return xmlrpc.client.DateTime(today)

server = SimpleXMLRPCServer(("localhost", 8000))
print("Listening on port 8000...")
server.register_function(today, "today")
server.serve_forever()

이전 서버에 대한 클라이언트 코드:

import xmlrpc.client
import datetime

proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")

today = proxy.today()
# convert the ISO8601 string to a datetime object
converted = datetime.datetime.strptime(today.value, "%Y%m%dT%H:%M:%S")
print("Today: %s" % converted.strftime("%d.%m.%Y, %H:%M"))

Binary 객체

class xmlrpc.client.Binary

이 클래스는 바이트열 데이터(NUL을 포함할 수 있습니다)로 초기화될 수 있습니다. Binary 객체의 내용에 대한 기본 액세스는 어트리뷰트에 의해 제공됩니다:

data

Binary 인스턴스로 캡슐화된 바이너리 데이터. 데이터는 bytes 객체로 제공됩니다.

Binary 객체에는 주로 마샬링/역마샬링 코드 내부에서 사용하기 위해 지원되는 다음과 같은 메서드가 있습니다:

decode(bytes)

base64 bytes 객체를 받아들이고 인스턴스의 새 데이터로 디코딩합니다.

encode(out)

이 바이너리 항목의 XML-RPC base64 인코딩을 out 스트림 객체에 씁니다.

인코딩된 데이터에는 RFC 2045 섹션 6.8 [https://datatracker.ietf.org/doc/html/rfc2045.html#section-6.8]에 따라 76문자마다 줄 바꿈이 있는데, 이는 XML-RPC 명세가 작성될 때 사실상 표준 base64 명세였습니다.

It also supports certain of Python’s built-in operators through __eq__() and __ne__() methods.

바이너리 객체의 사용 예. XMLRPC를 통해 이미지를 전송할 것입니다:

from xmlrpc.server import SimpleXMLRPCServer
import xmlrpc.client

def python_logo():
    with open("python_logo.jpg", "rb") as handle:
        return xmlrpc.client.Binary(handle.read())

server = SimpleXMLRPCServer(("localhost", 8000))
print("Listening on port 8000...")
server.register_function(python_logo, 'python_logo')

server.serve_forever()

클라이언트는 이미지를 가져와서 파일에 저장합니다:

import xmlrpc.client

proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
with open("fetched_python_logo.jpg", "wb") as handle:
    handle.write(proxy.python_logo().data)

Fault 객체

class xmlrpc.client.Fault

Fault 객체는 XML-RPC 결함 태그의 내용을 캡슐화합니다. Fault 객체에는 다음과 같은 어트리뷰트가 있습니다:

faultCode

An int indicating the fault type.

faultString

결함과 연관된 진단 메시지가 포함된 문자열.

다음 예제에서는 복소수 형의 객체를 반환하여 의도적으로 Fault를 발생시킵니다. 서버 코드:

from xmlrpc.server import SimpleXMLRPCServer

# A marshalling error is going to occur because we're returning a
# complex number
def add(x, y):
    return x+y+0j

server = SimpleXMLRPCServer(("localhost", 8000))
print("Listening on port 8000...")
server.register_function(add, 'add')

server.serve_forever()

이전 서버에 대한 클라이언트 코드:

import xmlrpc.client

proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
try:
    proxy.add(2, 5)
except xmlrpc.client.Fault as err:
    print("A fault occurred")
    print("Fault code: %d" % err.faultCode)
    print("Fault string: %s" % err.faultString)

ProtocolError 객체

class xmlrpc.client.ProtocolError

ProtocolError 객체는 하부 전송 계층에서의 프로토콜 에러를 기술합니다 (가령 URI로 명명된 서버가 없을 때 404 ‘not found’ 에러). 다음과 같은 어트리뷰트가 있습니다:

url

에러를 일으킨 URI나 URL.

errcode

에러 코드.

errmsg

에러 메시지나 진단 문자열.

headers

에러를 일으킨 HTTP/HTTPS 요청의 헤더를 포함하는 딕셔너리.

다음 예에서는 잘못된 URI를 제공하여 의도적으로 ProtocolError를 발생시킵니다:

import xmlrpc.client

# create a ServerProxy with a URI that doesn't respond to XMLRPC requests
proxy = xmlrpc.client.ServerProxy("http://google.com/")

try:
    proxy.some_method()
except xmlrpc.client.ProtocolError as err:
    print("A protocol error occurred")
    print("URL: %s" % err.url)
    print("HTTP/HTTPS headers: %s" % err.headers)
    print("Error code: %d" % err.errcode)
    print("Error message: %s" % err.errmsg)

MultiCall 객체

MultiCall 객체는 원격 서버에 대한 여러 호출을 단일 요청으로 캡슐화하는 방법을 제공합니다 [1].

class xmlrpc.client.MultiCall(server)

boxcar 메서드 호출에 사용되는 객체를 만듭니다. server는 최종 호출 대상입니다. 결과 객체를 호출할 수 있지만, 즉시 None을 반환하고, 호출 이름과 매개 변수를 MultiCall 객체에 저장하기만 합니다. 객체 자체를 호출하면 저장된 모든 호출이 단일 system.multicall 요청으로 전송됩니다. 이 호출의 결과는 제너레이터입니다; 이 제너레이터를 이터레이트 하면 개별 결과를 산출합니다.

이 클래스의 사용 예는 다음과 같습니다. 서버 코드:

from xmlrpc.server import SimpleXMLRPCServer

def add(x, y):
    return x + y

def subtract(x, y):
    return x - y

def multiply(x, y):
    return x * y

def divide(x, y):
    return x // y

# A simple server with simple arithmetic functions
server = SimpleXMLRPCServer(("localhost", 8000))
print("Listening on port 8000...")
server.register_multicall_functions()
server.register_function(add, 'add')
server.register_function(subtract, 'subtract')
server.register_function(multiply, 'multiply')
server.register_function(divide, 'divide')
server.serve_forever()

이전 서버에 대한 클라이언트 코드:

import xmlrpc.client

proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
multicall = xmlrpc.client.MultiCall(proxy)
multicall.add(7, 3)
multicall.subtract(7, 3)
multicall.multiply(7, 3)
multicall.divide(7, 3)
result = multicall()

print("7+3=%d, 7-3=%d, 7*3=%d, 7//3=%d" % tuple(result))

편의 함수

xmlrpc.client.dumps(params, methodname=None, methodresponse=None, encoding=None, allow_none=False)

params를 XML-RPC 요청으로, 또는 methodresponse가 참이면 응답으로 변환합니다. params는 인자의 튜플이거나 Fault 예외 클래스의 인스턴스일 수 있습니다. methodresponse가 참이면, 단일 값만 반환될 수 있는데, params의 길이가 1이어야 한다는 뜻입니다. 제공되면, encoding은 생성된 XML에서 사용할 인코딩입니다; 기본값은 UTF-8입니다. 파이썬의 None 값은 표준 XML-RPC에서 사용할 수 없습니다; 확장을 통해 이를 사용하려면 allow_none에 참값을 제공하십시오.

xmlrpc.client.loads(data, use_datetime=False, use_builtin_types=False)

XML-RPC 요청이나 응답을 파이썬 객체 (params, methodname)로 변환합니다. params는 인자의 튜플입니다; methodname은 문자열이거나 패킷에 메서드 이름이 없으면 None입니다. XML-RPC 패킷이 결함 조건을 나타내면, 이 함수는 Fault 예외를 발생시킵니다. use_builtin_types 플래그를 사용하여 날짜/시간 값을 datetime.datetime 객체로 표현하고 바이너리 데이터를 bytes 객체로 표현할 수 있습니다; 이 플래그는 기본적으로 거짓입니다.

사용되지 않는 use_datetime 플래그는 use_builtin_types와 유사하지만, 날짜/시간 값에만 적용됩니다.

버전 3.3에서 변경: use_builtin_types 플래그가 추가되었습니다.

클라이언트 사용 예

# simple test program (from the XML-RPC specification)
from xmlrpc.client import ServerProxy, Error

# server = ServerProxy("http://localhost:8000") # local server
with ServerProxy("http://betty.userland.com") as proxy:

    print(proxy)

    try:
        print(proxy.examples.getStateName(41))
    except Error as v:
        print("ERROR", v)

HTTP 프락시를 통해 XML-RPC 서버에 액세스하려면, 사용자 정의 트랜스포트를 정의해야 합니다. 다음 예제는 방법을 보여줍니다:

import http.client
import xmlrpc.client

class ProxiedTransport(xmlrpc.client.Transport):

    def set_proxy(self, host, port=None, headers=None):
        self.proxy = host, port
        self.proxy_headers = headers

    def make_connection(self, host):
        connection = http.client.HTTPConnection(*self.proxy)
        connection.set_tunnel(host, headers=self.proxy_headers)
        self._connection = host, connection
        return connection

transport = ProxiedTransport()
transport.set_proxy('proxy-server', 8080)
server = xmlrpc.client.ServerProxy('http://betty.userland.com', transport=transport)
print(server.examples.getStateName(41))

클라이언트와 서버 사용 예

SimpleXMLRPCServer 예제를 참조하십시오.

각주

[1]

이 접근법은 xmlrpc.com에서의 토론 [https://web.archive.org/web/20060624230303/http://www.xmlrpc.com/discuss/msgReader$1208?mode=topic]에서 처음 제시되었습니다.

xmlrpc.server — Basic XML-RPC servers

소스 코드: Lib/xmlrpc/server.py [https://github.com/python/cpython/tree/main/Lib/xmlrpc/server.py]

xmlrpc.server 모듈은 파이썬으로 작성된 XML-RPC 서버를 위한 기본 서버 프레임워크를 제공합니다. 서버는 SimpleXMLRPCServer를 사용하여 독립적이거나, CGIXMLRPCRequestHandler를 사용하여 CGI 환경에 내장될 수 있습니다.

경고

xmlrpc.server 모듈은 악의적으로 구성된 데이터로부터 안전하지 않습니다. 신뢰할 수 없거나 인증되지 않은 데이터를 구문 분석해야 한다면 XML 취약점를 참조하십시오.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

class xmlrpc.server.SimpleXMLRPCServer(addr, requestHandler=SimpleXMLRPCRequestHandler, logRequests=True, allow_none=False, encoding=None, bind_and_activate=True, use_builtin_types=False)

새 서버 인스턴스를 만듭니다. 이 클래스는 XML-RPC 프로토콜에 의해 호출될 수 있는 함수를 등록하는 메서드를 제공합니다. requestHandler 매개 변수는 요청 처리기 인스턴스의 팩토리여야 합니다; 기본값은 SimpleXMLRPCRequestHandler 입니다. addr과 requestHandler 매개 변수는 socketserver.TCPServer 생성자에 전달됩니다. logRequests가 참(기본값)이면, 요청이 로그 됩니다; 이 매개 변수를 거짓으로 설정하면 로깅이 해제됩니다. allow_none과 encoding 매개 변수는 xmlrpc.client로 전달되고 서버에서 반환될 XML-RPC 응답을 제어합니다. bind_and_activate 매개 변수는 생성자가 server_bind()와 server_activate()를 즉시 호출하는지를 제어합니다; 기본값은 참입니다. 이를 거짓으로 설정하면 코드가 주소가 바인드되기 전에 allow_reuse_address 클래스 변수를 조작할 수 있습니다. use_builtin_types 매개 변수는 loads() 함수로 전달되며 날짜/시간 값이나 바이너리 데이터가 수신될 때 처리되는 형을 제어합니다; 기본값은 거짓입니다.

버전 3.3에서 변경: use_builtin_types 플래그가 추가되었습니다.

class xmlrpc.server.CGIXMLRPCRequestHandler(allow_none=False, encoding=None, use_builtin_types=False)

CGI 환경에서 XML-RPC 요청을 처리할 새 인스턴스를 만듭니다. allow_none과 encoding 매개 변수는 xmlrpc.client로 전달되고 서버에서 반환될 XML-RPC 응답을 제어합니다. use_builtin_types 매개 변수는 loads() 함수로 전달되며 날짜/시간 값이나 바이너리 데이터가 수신될 때 처리되는 형을 제어합니다; 기본값은 거짓입니다.

버전 3.3에서 변경: use_builtin_types 플래그가 추가되었습니다.

class xmlrpc.server.SimpleXMLRPCRequestHandler

새 요청 처리기 인스턴스를 만듭니다. 이 요청 처리기는 POST 요청을 지원하고 SimpleXMLRPCServer 생성자 매개 변수에 대한 logRequests 매개 변수가 적용되도록 로깅을 수정합니다.

SimpleXMLRPCServer 객체

SimpleXMLRPCServer 클래스는 socketserver.TCPServer를 기반으로 하며 간단한 독립형 XML-RPC 서버를 작성하는 수단을 제공합니다.

SimpleXMLRPCServer.register_function(function=None, name=None)

Register a function that can respond to XML-RPC requests. If name is given, it will be the method name associated with function, otherwise function.__name__ will be used. name is a string, and may contain characters not legal in Python identifiers, including the period character.

This method can also be used as a decorator. When used as a decorator, name can only be given as a keyword argument to register function under name. If no name is given, function.__name__ will be used.

버전 3.7에서 변경: register_function()은 데코레이터로 사용할 수 있습니다.

SimpleXMLRPCServer.register_instance(instance, allow_dotted_names=False)

register_function()을 사용하여 등록되지 않은 메서드 이름을 노출하는데 사용되는 객체를 등록합니다. instance가 _dispatch() 메서드를 포함하면, 요청된 메서드 이름과 요청의 매개 변수로 호출됩니다. API는 def _dispatch(self, method, params)입니다 (params가 가변 인자 목록을 나타내지 않음에 유의하십시오). 이것이 작업을 수행하기 위해 하부 함수를 호출하면, 해당 함수를 매개 변수 리스트를 확장하여 func(*params)로 호출합니다. _dispatch()의 반환 값이 클라이언트에 결과로 반환됩니다. instance에 _dispatch() 메서드가 없으면, 요청된 메서드의 이름과 일치하는 어트리뷰트를 검색합니다.

선택적 allow_dotted_names 인자가 참이고 인스턴스에 _dispatch() 메서드가 없으면, 요청된 메서드 이름에 마침표가 포함될 때, 메서드 이름의 각 구성 요소가 개별적으로 검색되어, 간단한 계층 구조 검색이 수행되는 효과를 줍니다. 이 검색에서 찾은 값은 요청의 매개 변수로 호출되며 반환 값은 클라이언트로 다시 전달됩니다.

경고

allow_dotted_names 옵션을 활성화하면 침입자가 모듈의 전역 변수에 액세스할 수 있으며 침입자가 여러분의 기계에서 임의의 코드를 실행할 수 있습니다. 안전한 폐쇄 네트워크에서만 이 옵션을 사용하십시오.

SimpleXMLRPCServer.register_introspection_functions()

XML-RPC 내부 검사 함수 system.listMethods, system.methodHelp 및 system.methodSignature를 등록합니다.

SimpleXMLRPCServer.register_multicall_functions()

XML-RPC 다중 호출(multicall) 함수 system.multicall을 등록합니다.

SimpleXMLRPCRequestHandler.rpc_paths

XML-RPC 요청을 수신하기 위한 URL의 유효한 경로 부분을 나열하는 튜플이어야 하는 어트리뷰트 값. 다른 경로로 들어오는 요청은 404 “no such page” HTTP 에러를 발생시킵니다. 이 튜플이 비어 있으면, 모든 경로를 유효한 것으로 간주합니다. 기본값은 ('/', '/RPC2')입니다.

SimpleXMLRPCServer 예제

서버 코드:

from xmlrpc.server import SimpleXMLRPCServer
from xmlrpc.server import SimpleXMLRPCRequestHandler

# Restrict to a particular path.
class RequestHandler(SimpleXMLRPCRequestHandler):
    rpc_paths = ('/RPC2',)

# Create server
with SimpleXMLRPCServer(('localhost', 8000),
                        requestHandler=RequestHandler) as server:
    server.register_introspection_functions()

    # Register pow() function; this will use the value of
    # pow.__name__ as the name, which is just 'pow'.
    server.register_function(pow)

    # Register a function under a different name
    def adder_function(x, y):
        return x + y
    server.register_function(adder_function, 'add')

    # Register an instance; all the methods of the instance are
    # published as XML-RPC methods (in this case, just 'mul').
    class MyFuncs:
        def mul(self, x, y):
            return x * y

    server.register_instance(MyFuncs())

    # Run the server's main loop
    server.serve_forever()

다음 클라이언트 코드는 앞의 서버가 제공하는 메서드를 호출합니다:

import xmlrpc.client

s = xmlrpc.client.ServerProxy('http://localhost:8000')
print(s.pow(2,3))  # Returns 2**3 = 8
print(s.add(2,3))  # Returns 5
print(s.mul(5,2))  # Returns 5*2 = 10

# Print list of available methods
print(s.system.listMethods())

register_function()은 데코레이터로도 사용할 수 있습니다. 앞의 서버 예제에서 데코레이터 방식으로 함수를 등록할 수 있습니다:

from xmlrpc.server import SimpleXMLRPCServer
from xmlrpc.server import SimpleXMLRPCRequestHandler

class RequestHandler(SimpleXMLRPCRequestHandler):
    rpc_paths = ('/RPC2',)

with SimpleXMLRPCServer(('localhost', 8000),
                        requestHandler=RequestHandler) as server:
    server.register_introspection_functions()

    # Register pow() function; this will use the value of
    # pow.__name__ as the name, which is just 'pow'.
    server.register_function(pow)

    # Register a function under a different name, using
    # register_function as a decorator. *name* can only be given
    # as a keyword argument.
    @server.register_function(name='add')
    def adder_function(x, y):
        return x + y

    # Register a function under function.__name__.
    @server.register_function
    def mul(x, y):
        return x * y

    server.serve_forever()

Lib/xmlrpc/server.py 모듈에 포함된 다음 예는 점으로 구분된 이름을 허용하고 다중 호출 함수를 등록하는 서버를 보여줍니다.

경고

allow_dotted_names 옵션을 활성화하면 침입자가 모듈의 전역 변수에 액세스할 수 있으며 침입자가 여러분의 기계에서 임의의 코드를 실행할 수 있습니다. 이 예제는 안전한 폐쇄 네트워크 내에서만 사용하십시오.

import datetime

class ExampleService:
    def getData(self):
        return '42'

    class currentTime:
        @staticmethod
        def getCurrentTime():
            return datetime.datetime.now()

with SimpleXMLRPCServer(("localhost", 8000)) as server:
    server.register_function(pow)
    server.register_function(lambda x,y: x+y, 'add')
    server.register_instance(ExampleService(), allow_dotted_names=True)
    server.register_multicall_functions()
    print('Serving XML-RPC on localhost port 8000')
    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print("\nKeyboard interrupt received, exiting.")
        sys.exit(0)

이 ExampleService 데모는 명령 줄에서 호출할 수 있습니다:

python -m xmlrpc.server

The client that interacts with the above server is included in Lib/xmlrpc/client.py:

server = ServerProxy("http://localhost:8000")

try:
    print(server.currentTime.getCurrentTime())
except Error as v:
    print("ERROR", v)

multi = MultiCall(server)
multi.getData()
multi.pow(2,9)
multi.add(1,2)
try:
    for response in multi():
        print(response)
except Error as v:
    print("ERROR", v)

데모 XMLRPC 서버와 상호 작용하는 이 클라이언트는 다음과 같이 호출할 수 있습니다:

python -m xmlrpc.client

CGIXMLRPCRequestHandler

CGIXMLRPCRequestHandler 클래스는 파이썬 CGI 스크립트로 전송된 XML-RPC 요청을 처리하는 데 사용할 수 있습니다.

CGIXMLRPCRequestHandler.register_function(function=None, name=None)

Register a function that can respond to XML-RPC requests. If name is given, it will be the method name associated with function, otherwise function.__name__ will be used. name is a string, and may contain characters not legal in Python identifiers, including the period character.

This method can also be used as a decorator. When used as a decorator, name can only be given as a keyword argument to register function under name. If no name is given, function.__name__ will be used.

버전 3.7에서 변경: register_function()은 데코레이터로 사용할 수 있습니다.

CGIXMLRPCRequestHandler.register_instance(instance)

register_function()을 사용하여 등록되지 않은 메서드 이름을 노출하는데 사용되는 객체를 등록합니다. instance가 _dispatch() 메서드를 포함하면, 요청된 메서드 이름과 요청의 매개 변수로 호출됩니다; 반환 값이 클라이언트에 결과로 반환됩니다. instance에 _dispatch() 메서드가 없으면, 요청된 메서드의 이름과 일치하는 어트리뷰트를 검색합니다; 요청된 메서드 이름에 마침표가 포함될 때, 메서드 이름의 각 구성 요소가 개별적으로 검색되어, 간단한 계층 구조 검색이 수행되는 효과를 줍니다. 이 검색에서 찾은 값은 요청의 매개 변수로 호출되며 반환 값은 클라이언트로 다시 전달됩니다.

CGIXMLRPCRequestHandler.register_introspection_functions()

XML-RPC 내부 검사 함수 system.listMethods, system.methodHelp 및 system.methodSignature를 등록합니다.

CGIXMLRPCRequestHandler.register_multicall_functions()

XML-RPC 다중 호출(multicall) 함수 system.multicall을 등록합니다.

CGIXMLRPCRequestHandler.handle_request(request_text=None)

XML-RPC 요청을 처리합니다. request_text가 제공되면, HTTP 서버가 제공한 POST 데이터여야 합니다, 그렇지 않으면 stdin의 내용이 사용됩니다.

예:

class MyFuncs:
    def mul(self, x, y):
        return x * y

handler = CGIXMLRPCRequestHandler()
handler.register_function(pow)
handler.register_function(lambda x,y: x+y, 'add')
handler.register_introspection_functions()
handler.register_instance(MyFuncs())
handler.handle_request()

XMLRPC 서버 문서화

이 클래스들은 HTTP GET 요청에 대한 응답으로 HTML 설명서를 제공하기 위해 위의 클래스를 확장합니다. 서버는 DocXMLRPCServer를 사용하여 독립적이거나, DocCGIXMLRPCRequestHandler를 사용하여 CGI 환경에 내장될 수 있습니다.

class xmlrpc.server.DocXMLRPCServer(addr, requestHandler=DocXMLRPCRequestHandler, logRequests=True, allow_none=False, encoding=None, bind_and_activate=True, use_builtin_types=True)

새 서버 인스턴스를 만듭니다. 모든 매개 변수는 SimpleXMLRPCServer와 같은 의미입니다; requestHandler의 기본값은 DocXMLRPCRequestHandler 입니다.

버전 3.3에서 변경: use_builtin_types 플래그가 추가되었습니다.

class xmlrpc.server.DocCGIXMLRPCRequestHandler

CGI 환경에서 XML-RPC 요청을 처리할 새 인스턴스를 만듭니다.

class xmlrpc.server.DocXMLRPCRequestHandler

새 요청 처리기 인스턴스를 만듭니다. 이 요청 처리기는 XML-RPC POST 요청과 설명서 GET 요청을 지원하고, DocXMLRPCServer 생성자 매개 변수에 대한 logRequests 매개 변수가 적용되도록 로깅을 수정합니다.

DocXMLRPCServer 객체

DocXMLRPCServer 클래스는 SimpleXMLRPCServer 에서 파생되며 스스로 설명하는 독립형 XML-RPC 서버를 만드는 수단을 제공합니다. HTTP POST 요청은 XML-RPC 메서드 호출로 처리됩니다. HTTP GET 요청은 pydoc 스타일 HTML 문서를 생성하는 것으로 처리합니다. 이를 통해 서버는 자체 웹 기반 설명서를 제공할 수 있습니다.

DocXMLRPCServer.set_server_title(server_title)

생성된 HTML 설명서에 사용되는 제목을 설정합니다. 이 제목은 HTML “title” 요소 안에서 사용됩니다.

DocXMLRPCServer.set_server_name(server_name)

생성된 HTML 설명서에 사용되는 이름을 설정합니다. 이 이름은 설명서의 최상단의 “h1” 요소 안에 나타납니다.

DocXMLRPCServer.set_server_documentation(server_documentation)

생성된 HTML 설명서에 사용되는 설명을 설정합니다. 이 설명은 설명서에서 서버 이름 아래 단락으로 나타납니다.

DocCGIXMLRPCRequestHandler

DocCGIXMLRPCRequestHandler 클래스는 CGIXMLRPCRequestHandler 에서 파생되며 스스로 설명하는 XML-RPC CGI 스크립트를 만드는 수단을 제공합니다. HTTP POST 요청은 XML-RPC 메서드 호출로 처리됩니다. HTTP GET 요청은 pydoc 스타일 HTML 문서를 생성하는 것으로 처리합니다. 이를 통해 서버는 자체 웹 기반 설명서를 제공할 수 있습니다.

DocCGIXMLRPCRequestHandler.set_server_title(server_title)

생성된 HTML 설명서에 사용되는 제목을 설정합니다. 이 제목은 HTML “title” 요소 안에서 사용됩니다.

DocCGIXMLRPCRequestHandler.set_server_name(server_name)

생성된 HTML 설명서에 사용되는 이름을 설정합니다. 이 이름은 설명서의 최상단의 “h1” 요소 안에 나타납니다.

DocCGIXMLRPCRequestHandler.set_server_documentation(server_documentation)

생성된 HTML 설명서에 사용되는 설명을 설정합니다. 이 설명은 설명서에서 서버 이름 아래 단락으로 나타납니다.

ipaddress — IPv4/IPv6 manipulation library

소스 코드: Lib/ipaddress.py [https://github.com/python/cpython/tree/main/Lib/ipaddress.py]

ipaddress는 IPv4와 IPv6 주소와 네트워크를 만들고, 조작하고, 연산하는 기능을 제공합니다.

이 모듈의 함수와 클래스를 사용하면 두 호스트가 같은 서브 네트에 있는지 확인하기, 특정 서브 네트의 모든 호스트를 이터레이트 하기, 문자열이 유효한 IP 주소나 네트워크를 나타내는지 검사하기 등 IP 주소와 관련된 다양한 작업을 간단하게 처리할 수 있습니다.

이것은 전체 모듈 API 레퍼런스입니다 - 개요와 소개는 ipaddress 모듈에 대한 소개를 참조하십시오.

Added in version 3.3.

편의 팩토리 함수

ipaddress 모듈은 IP 주소, 네트워크 및 인터페이스를 편리하게 만드는 팩토리 함수를 제공합니다:

ipaddress.ip_address(address)

Return an IPv4Address or IPv6Address object depending on the IP address passed as argument. Either IPv4 or IPv6 addresses may be supplied; integers less than 2**32 will be considered to be IPv4 by default. A ValueError is raised if address does not represent a valid IPv4 or IPv6 address.

>>> ipaddress.ip_address('192.168.0.1')
IPv4Address('192.168.0.1')
>>> ipaddress.ip_address('2001:db8::')
IPv6Address('2001:db8::')

ipaddress.ip_network(address, strict=True)

Return an IPv4Network or IPv6Network object depending on the IP address passed as argument. address is a string or integer representing the IP network. Either IPv4 or IPv6 networks may be supplied; integers less than 2**32 will be considered to be IPv4 by default. strict is passed to IPv4Network or IPv6Network constructor. A ValueError is raised if address does not represent a valid IPv4 or IPv6 address, or if the network has host bits set.

>>> ipaddress.ip_network('192.168.0.0/28')
IPv4Network('192.168.0.0/28')

ipaddress.ip_interface(address)

Return an IPv4Interface or IPv6Interface object depending on the IP address passed as argument. address is a string or integer representing the IP address. Either IPv4 or IPv6 addresses may be supplied; integers less than 2**32 will be considered to be IPv4 by default. A ValueError is raised if address does not represent a valid IPv4 or IPv6 address.

이러한 편의 함수들의 한 가지 단점은 IPv4와 IPv6 형식을 모두 처리해야 한다는 것이, 함수가 IPv4나 IPv6 형식 중 어느 것을 의도하는지 알 수 없기 때문에, 에러 메시지가 정확한 에러에 대한 정보를 최소한으로만 제공한다는 것을 의미한다는 것입니다. 적절한 버전 별 클래스 생성자를 직접 호출하여 더 자세한 에러 보고를 얻을 수 있습니다.

IP 주소

주소 객체

IPv4Address와 IPv6Address 객체는 많은 공통 어트리뷰트를 공유합니다. IPv6 주소에만 의미가 있는 일부 어트리뷰트는 두 IP 버전을 모두 올바르게 처리하는 코드를 더 쉽게 작성할 수 있도록 IPv4Address 객체에 의해 구현됩니다. 주소 객체는 해시 가능해서, 딕셔너리에서 키로 사용할 수 있습니다.

class ipaddress.IPv4Address(address)

IPv4 주소를 구성합니다. address가 유효한 IPv4 주소가 아니면 AddressValueError 가 발생합니다.

다음은 유효한 IPv4 주소를 구성합니다:

A string in decimal-dot notation, consisting of four decimal integers in the inclusive range 0–255, separated by dots (e.g. 192.168.0.1). Each integer represents an octet (byte) in the address. Leading zeroes are not tolerated to prevent confusion with octal notation.

32비트에 맞는 정수.

길이가 4인 bytes 객체에 채워진 정수 (가장 유효한 옥텟이 먼저 옵니다).

>>> ipaddress.IPv4Address('192.168.0.1')
IPv4Address('192.168.0.1')
>>> ipaddress.IPv4Address(3232235521)
IPv4Address('192.168.0.1')
>>> ipaddress.IPv4Address(b'\xC0\xA8\x00\x01')
IPv4Address('192.168.0.1')

버전 3.8에서 변경: Leading zeros are tolerated, even in ambiguous cases that look like octal notation.

버전 3.9.5에서 변경: Leading zeros are no longer tolerated and are treated as an error. IPv4 address strings are now parsed as strict as glibc inet_pton().

version

적절한 버전 번호: IPv4의 경우 4, IPv6의 경우 6.

버전 3.14에서 변경: Made available on the class.

max_prefixlen

이 버전에 대한 주소 표현의 총 비트 수: IPv4의 경우 32, IPv6의 경우 128.

접두사는 주소가 네트워크의 일부인지를 판별하기 위해 비교되는 주소의 선행 비트 수를 정의합니다.

버전 3.14에서 변경: Made available on the class.

compressed

exploded

점으로 구분된 십진 표기법의 문자열 표현. 선행 0은 표현에 포함되지 않습니다.

IPv4는 옥텟이 0으로 설정된 주소에 대한 약식 표기법을 정의하지 않기 때문에, 이 두 어트리뷰트는 IPv4 주소의 경우 항상 str(addr)과 같습니다. 이러한 어트리뷰트를 노출하면 IPv4와 IPv6 주소를 모두 처리할 수 있는 디스플레이 코드를 더 쉽게 작성할 수 있습니다.

packed

이 주소의 바이너리 표현 - 적절한 길이의 bytes 객체 (가장 유효한 옥텟이 먼저 옵니다). IPv4의 경우 4바이트, IPv6의 경우 16바이트입니다.

reverse_pointer

IP 주소에 대한 역 DNS PTR 레코드의 이름, 예를 들어:

>>> ipaddress.ip_address("127.0.0.1").reverse_pointer
'1.0.0.127.in-addr.arpa'
>>> ipaddress.ip_address("2001:db8::1").reverse_pointer
'1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa'

이 이름은 결정된(resolved) 호스트명 자체가 아니라 PTR 조회를 수행하는 데 사용할 수 있는 이름입니다.

Added in version 3.5.

is_multicast

주소가 멀티캐스트용으로 예약되었으면 True. RFC 3171 [https://datatracker.ietf.org/doc/html/rfc3171.html](IPv4의 경우)이나 RFC 2373 [https://datatracker.ietf.org/doc/html/rfc2373.html](IPv6의 경우)을 참조하십시오.

is_private

True if the address is defined as not globally reachable by iana-ipv4-special-registry [https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml] (for IPv4) or iana-ipv6-special-registry [https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml] (for IPv6) with the following exceptions:

is_private is False for the shared address space (100.64.0.0/10)

For IPv4-mapped IPv6-addresses the is_private value is determined by the semantics of the underlying IPv4 addresses and the following condition holds (see IPv6Address.ipv4_mapped):

address.is_private == address.ipv4_mapped.is_private

is_private has value opposite to is_global, except for the shared address space (100.64.0.0/10 range) where they are both False.

버전 3.13에서 변경: Fixed some false positives and false negatives.

192.0.0.0/24 is considered private with the exception of 192.0.0.9/32 and 192.0.0.10/32 (previously: only the 192.0.0.0/29 sub-range was considered private).

64:ff9b:1::/48 is considered private.

2002::/16 is considered private.

There are exceptions within 2001::/23 (otherwise considered private): 2001:1::1/128, 2001:1::2/128, 2001:3::/32, 2001:4:112::/48, 2001:20::/28, 2001:30::/28. The exceptions are not considered private.

is_global

True if the address is defined as globally reachable by iana-ipv4-special-registry [https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml] (for IPv4) or iana-ipv6-special-registry [https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml] (for IPv6) with the following exception:

For IPv4-mapped IPv6-addresses the is_private value is determined by the semantics of the underlying IPv4 addresses and the following condition holds (see IPv6Address.ipv4_mapped):

address.is_global == address.ipv4_mapped.is_global

is_global has value opposite to is_private, except for the shared address space (100.64.0.0/10 range) where they are both False.

Added in version 3.4.

버전 3.13에서 변경: Fixed some false positives and false negatives, see is_private for details.

is_unspecified

주소가 지정되지 않았으면 True. RFC 5735 [https://datatracker.ietf.org/doc/html/rfc5735.html](IPv4의 경우)나 RFC 2373 [https://datatracker.ietf.org/doc/html/rfc2373.html](IPv6의 경우)을 참조하십시오.

is_reserved

주소가 그 외에 IETF 예약되었으면 True.

is_loopback

이것이 루프 백 주소이면 True. RFC 3330 [https://datatracker.ietf.org/doc/html/rfc3330.html](IPv4의 경우)이나 RFC 2373 [https://datatracker.ietf.org/doc/html/rfc2373.html](IPv6의 경우)을 참조하십시오.

is_link_local

주소가 링크 로컬 사용을 위해 예약되었으면 True. RFC 3927 [https://datatracker.ietf.org/doc/html/rfc3927.html]을 참조하십시오.

ipv6_mapped

IPv4Address object representing the IPv4-mapped IPv6 address. See RFC 4291 [https://datatracker.ietf.org/doc/html/rfc4291.html].

Added in version 3.13.

IPv4Address.__format__(fmt)

명시적 포맷 문자열로 제어되는 IP 주소의 문자열 표현을 반환합니다. fmt는 다음 중 하나일 수 있습니다: str()과 동등한 기본 옵션인 's', 0으로 채워진 이진수 문자열을 위한 'b', 대문자나 소문자 16진수 표현을 위한 'X'나 'x', 또는 IPv4 주소의 경우 'b'와 IPv6의 경우 'x'와 동등한 'n'. 이진수와 16진수 표현의 경우, 형식 지정자 '#'과 그룹화 옵션 '_'를 사용할 수 있습니다. __format__은 format, str.format 및 f-문자열에서 사용됩니다.

>>> format(ipaddress.IPv4Address('192.168.0.1'))
'192.168.0.1'
>>> '{:#b}'.format(ipaddress.IPv4Address('192.168.0.1'))
'0b11000000101010000000000000000001'
>>> f'{ipaddress.IPv6Address("2001:db8::1000"):s}'
'2001:db8::1000'
>>> format(ipaddress.IPv6Address('2001:db8::1000'), '_X')
'2001_0DB8_0000_0000_0000_0000_0000_1000'
>>> '{:#_n}'.format(ipaddress.IPv6Address('2001:db8::1000'))
'0x2001_0db8_0000_0000_0000_0000_0000_1000'

Added in version 3.9.

class ipaddress.IPv6Address(address)

IPv6 주소를 구성합니다. address가 유효한 IPv6 주소가 아니면 AddressValueError 가 발생합니다.

다음은 유효한 IPv6 주소를 구성합니다:

4개의 16진수로 구성된 그룹 8개로 구성된 문자열, 각 그룹은 16비트를 나타냅니다. 그룹은 콜론으로 구분됩니다. 이것은 펼쳐진(exploded) (longhand) 표기법을 기술합니다. 문자열은 다양한 방법으로 압축될(compressed) (약식 표기법) 수도 있습니다. 자세한 내용은 RFC 4291 [https://datatracker.ietf.org/doc/html/rfc4291.html]을 참조하십시오. 예를 들어, "0000:0000:0000:0000:0000:0abc:0007:0def"는 "::abc:7:def"로 압축될 수 있습니다.

선택적으로, 문자열은 접미사 %scope_id로 표시되는 스코프 존(scope zone) ID를 가질 수도 있습니다. 존재하면, 스코프 ID는 비어 있지 않아야 하며, %를 포함할 수 없습니다. 자세한 내용은 RFC 4007 [https://datatracker.ietf.org/doc/html/rfc4007.html]을 참조하십시오. 예를 들어, fe80::1234%1는 노드의 첫 번째 링크에서 주소 fe80::1234를 식별할 수 있습니다.

128비트에 맞는 정수.

길이가 16인 bytes 객체에 채워진 정수, 빅 엔디안.

>>> ipaddress.IPv6Address('2001:db8::1000')
IPv6Address('2001:db8::1000')
>>> ipaddress.IPv6Address('ff02::5678%1')
IPv6Address('ff02::5678%1')

compressed

주소 표현의 짧은 형식, 그룹에서 선행 0을 생략하고 0으로만 구성된 그룹의 가장 긴 시퀀스를 하나의 빈 그룹으로 축소됩니다.

이것은 IPv6 주소에 대해 str(addr)가 반환하는 값이기도 합니다.

exploded

주소 표현의 긴 형식, 모든 선행 0과 완전히 0으로 구성된 그룹이 포함됩니다.

다음 어트리뷰트와 메서드에 대해서는, IPv4Address 클래스의 해당 설명서를 참조하십시오:

packed

reverse_pointer

version

max_prefixlen

is_multicast

is_private

is_global

Added in version 3.4.

is_unspecified

is_reserved

is_loopback

is_link_local

is_site_local

주소가 사이트 로컬 사용을 위해 예약되었으면 True. 사이트 로컬 주소 공간은 RFC 3879 [https://datatracker.ietf.org/doc/html/rfc3879.html]에서 폐지되었음에 유의하십시오. is_private를 사용하여 이 주소가 RFC 4193 [https://datatracker.ietf.org/doc/html/rfc4193.html]에 의해 정의된 고유한 로컬 주소 공간에 있는지 검사하십시오.

ipv4_mapped

IPv4에 매핑된 주소(::FFFF/96으로 시작합니다)로 표시되는 주소의 경우, 이 프로퍼티는 내장 IPv4 주소를 보고합니다. 다른 주소의 경우, 이 프로퍼티는 None이 됩니다.

scope_id

RFC 4007 [https://datatracker.ietf.org/doc/html/rfc4007.html]에서 정의된 스코프 지정된 주소의 경우, 이 프로퍼티는 주소가 속한 주소 스코프의 특정 존(zone)을 문자열로 식별합니다. 스코프 존이 지정되지 않았으면, 이 프로퍼티는 None입니다.

sixtofour

RFC 3056 [https://datatracker.ietf.org/doc/html/rfc3056.html]에서 정의한 6to4 주소(2002::/16으로 시작합니다)인 것으로 보이는 주소의 경우, 이 프로퍼티는 내장 IPv4 주소를 보고합니다. 다른 주소의 경우, 이 프로퍼티는 None이 됩니다.

teredo

RFC 4380 [https://datatracker.ietf.org/doc/html/rfc4380.html]에서 정의한 Teredo 주소(2001::/32로 시작합니다)인 것으로 보이는 주소의 경우, 이 프로퍼티는 내장 (server, client) IP 주소 쌍을 보고합니다. 다른 주소의 경우, 이 프로퍼티는 None이 됩니다.

IPv6Address.__format__(fmt)

IPv4Address 의 해당 메서드 설명서를 참조하십시오.

Added in version 3.9.

문자열과 정수로의 변환

socket 모듈과 같은 네트워킹 인터페이스와 상호 운용하려면, 주소를 문자열이나 정수로 변환해야 합니다. 이것은 str()과 int() 내장 함수를 사용하여 처리됩니다:

>>> str(ipaddress.IPv4Address('192.168.0.1'))
'192.168.0.1'
>>> int(ipaddress.IPv4Address('192.168.0.1'))
3232235521
>>> str(ipaddress.IPv6Address('::1'))
'::1'
>>> int(ipaddress.IPv6Address('::1'))
1

IPv6 스코프 지정된 주소는 스코프 존 ID 없이 정수로 변환됨에 유의하십시오.

연산자

주소 객체는 일부 연산자를 지원합니다. 달리 명시하지 않는 한, 연산자는 호환 가능한 객체 간에만 적용할 수 있습니다 (즉 IPv4와 IPv4, IPv6와 IPv6).

비교 연산자

주소 객체는 일반적인 비교 연산자 집합으로 비교할 수 있습니다. 다른 스코프 존(scope zone) ID를 가진 같은 IPv6 주소는 같지 않습니다. 몇 가지 예:

>>> IPv4Address('127.0.0.2') > IPv4Address('127.0.0.1')
True
>>> IPv4Address('127.0.0.2') == IPv4Address('127.0.0.1')
False
>>> IPv4Address('127.0.0.2') != IPv4Address('127.0.0.1')
True
>>> IPv6Address('fe80::1234') == IPv6Address('fe80::1234%1')
False
>>> IPv6Address('fe80::1234%1') != IPv6Address('fe80::1234%2')
True

산술 연산자

주소 객체에 정수를 더하거나 뺄 수 있습니다. 몇 가지 예:

>>> IPv4Address('127.0.0.2') + 3
IPv4Address('127.0.0.5')
>>> IPv4Address('127.0.0.2') - 3
IPv4Address('126.255.255.255')
>>> IPv4Address('255.255.255.255') + 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ipaddress.AddressValueError: 4294967296 (>= 2**32) is not permitted as an IPv4 address

IP 네트워크 정의

IPv4Network 와 IPv6Network 객체는 IP 네트워크 정의를 정의하고 검사하기 위한 메커니즘을 제공합니다. 네트워크 정의는 마스크(mask)와 네트워크 주소(network address)로 구성되며, 마스크로 마스크 (바이너리 AND) 될 때 네트워크 주소와 같은 IP 주소 범위를 정의합니다. 예를 들어,, 마스크 255.255.255.0과 네트워크 주소 192.168.1.0으로 구성된 네트워크 정의는 192.168.1.0에서 192.168.1.255까지의 IP 주소로 구성됩니다.

접두사, 네트 마스크 및 호스트 마스크

IP 네트워크 마스크를 지정하는 몇 가지 동등한 방법이 있습니다. 접두사(prefix) /<nbits>는 네트워크 마스크에 설정된 상위 비트 수를 나타내는 표기법입니다. 네트 마스크(net mask)는 몇 개의 상위 비트가 설정된 IP 주소입니다. 따라서 접두사 /24는 IPv4에서 네트 마스크 255.255.255.0, 또는 IPv6에서 ffff:ff00::와 동등합니다. 또한 호스트 마스크(host mask)는 네트 마스크(net mask)의 논리적 역전이며, 때로 네트워크 마스크를 나타내기 위해 (예를 들어 Cisco 접근 제어 목록에서) 사용됩니다. IPv4에서 /24에 해당하는 호스트 마스크는 0.0.0.255입니다.

네트워크 객체

주소 객체가 구현하는 모든 어트리뷰트는 네트워크 객체도 구현합니다. 또한, 네트워크 객체는 추가 어트리뷰트를 구현합니다. 이 모든 것은 IPv4Network 와 IPv6Network 사이에서 공통이라서, 중복을 피하고자 IPv4Network 에 대해서만 설명됩니다. 네트워크 객체는 해시 가능해서 딕셔너리에서 키로 사용할 수 있습니다.

class ipaddress.IPv4Network(address, strict=True)

IPv4 네트워크 정의를 구성합니다. address는 다음 중 하나일 수 있습니다:

IP 주소와 선택적 마스크로 구성되고, 슬래시(/)로 구분된 문자열. IP 주소는 네트워크 주소이며, 마스크는 접두사를 뜻하는 단일 숫자이거나 IPv4 주소의 문자열 표현일 수 있습니다. 후자의 경우, 마스크는 0이 아닌 필드로 시작하면 네트 마스크로, 또는 0으로 시작하면 호스트 마스크로 해석되는데, 네트 마스크로 취급되는 모든 0인 마스크만 유일한 예외입니다. 마스크가 제공되지 않으면, /32로 간주합니다.

예를 들어, 다음 address 명세는 동등합니다: 192.168.1.0/24, 192.168.1.0/255.255.255.0 및 192.168.1.0/0.0.0.255.

32비트에 맞는 정수. 이는 네트워크 주소가 address이고 마스크가 /32인 단일 주소 네트워크와 동등합니다.

길이가 4인 bytes 객체에 채워진 정수, 빅 엔디안. 해석은 정수 address와 유사합니다.

A two-tuple of an address description and a netmask, where the address description is either a string, a 32-bits integer, a 4-bytes packed integer, or an existing IPv4Address object; and the netmask is either an integer representing the prefix length (e.g. 24) or a string representing the prefix mask (e.g. 255.255.255.0).

address가 유효한 IPv4 주소가 아니면 AddressValueError 가 발생합니다. 마스크가 IPv4 주소에 유효하지 않으면 NetmaskValueError 가 발생합니다.

strict가 True이고 제공된 address에 호스트 비트가 설정되면, ValueError가 발생합니다. 그렇지 않으면, 적절한 네트워크 주소를 결정하기 위해 호스트 비트가 마스크 되어 제거됩니다.

달리 명시되지 않는 한, 다른 네트워크/주소 객체를 받아들이는 모든 네트워크 메서드는 인자의 IP 버전이 self와 호환되지 않으면 TypeError를 발생시킵니다.

버전 3.5에서 변경: address 생성자 매개 변수에 대해 2-튜플 형식을 추가했습니다.

version

max_prefixlen

IPv4Address 의 해당 어트리뷰트 설명서를 참조하십시오.

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

이 어트리뷰트들은 네트워크 주소와 브로드 캐스트 주소 모두에 대해 참이면 네트워크 전체에 대해 참입니다.

network_address

네트워크의 네트워크 주소. 네트워크 주소와 접두사 길이는 네트워크를 고유하게 정의합니다.

broadcast_address

네트워크의 브로드 캐스트 주소. 브로드 캐스트 주소로 전송된 패킷은 네트워크의 모든 호스트가 수신해야 합니다.

hostmask

IPv4Address 객체로 제공되는 호스트 마스크.

netmask

IPv4Address 객체로 제공되는 네트 마스크.

with_prefixlen

compressed

exploded

접두사 표기법의 마스크를 갖는 네트워크의 문자열 표현.

with_prefixlen과 compressed는 항상 str(network)와 같습니다. exploded는 펼쳐진 형식의 네트워크 주소를 사용합니다.

with_netmask

네트 마스크 표기법의 마스크를 갖는 네트워크의 문자열 표현.

with_hostmask

호스트 마스크 표기법의 마스크를 갖는 네트워크의 문자열 표현.

num_addresses

네트워크의 총 주소 수.

prefixlen

네트워크 접두사 길이, 비트 단위.

hosts()

네트워크에서 사용 가능한 호스트에 대한 이터레이터를 반환합니다. 사용 가능한 호스트는 네트워크 주소 자체와 네트워크 브로드 캐스트 주소를 제외하고, 네트워크에 속하는 IP 주소입니다. 마스크 길이가 31인 네트워크의 경우, 네트워크 주소와 네트워크 브로드 캐스트 주소도 결과에 포함됩니다. 마스크가 32인 네트워크는 단일 호스트 주소가 포함된 리스트를 반환합니다.

>>> list(ip_network('192.0.2.0/29').hosts())
[IPv4Address('192.0.2.1'), IPv4Address('192.0.2.2'),
 IPv4Address('192.0.2.3'), IPv4Address('192.0.2.4'),
 IPv4Address('192.0.2.5'), IPv4Address('192.0.2.6')]
>>> list(ip_network('192.0.2.0/31').hosts())
[IPv4Address('192.0.2.0'), IPv4Address('192.0.2.1')]
>>> list(ip_network('192.0.2.1/32').hosts())
[IPv4Address('192.0.2.1')]

overlaps(other)

이 네트워크가 other에 부분적으로나 전체적으로 포함되어 있거나 other가 이 네트워크에 완전히 포함되면 True.

address_exclude(network)

지정된 network를 이 네트워크에서 제거하여 만들어지는 네트워크 정의를 계산합니다. 네트워크 객체의 이터레이터를 반환합니다. 이 네트워크에 network가 완전히 포함되지 않으면 ValueError가 발생합니다.

>>> n1 = ip_network('192.0.2.0/28')
>>> n2 = ip_network('192.0.2.1/32')
>>> list(n1.address_exclude(n2))
[IPv4Network('192.0.2.8/29'), IPv4Network('192.0.2.4/30'),
 IPv4Network('192.0.2.2/31'), IPv4Network('192.0.2.0/32')]

subnets(prefixlen_diff=1, new_prefix=None)

인자 값에 따라, 현재 네트워크 정의를 만들기 위해 참여하는 서브 네트들. prefixlen_diff는 우리의 접두사 길이를 늘여야 하는 양입니다. new_prefix는 서브 네트의 원하는 새 접두사입니다; 우리의 접두사보다 커야 합니다. prefixlen_diff와 new_prefix 중 하나만 설정해야 합니다. 네트워크 객체의 이터레이터를 반환합니다.

>>> list(ip_network('192.0.2.0/24').subnets())
[IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/25')]
>>> list(ip_network('192.0.2.0/24').subnets(prefixlen_diff=2))
[IPv4Network('192.0.2.0/26'), IPv4Network('192.0.2.64/26'),
 IPv4Network('192.0.2.128/26'), IPv4Network('192.0.2.192/26')]
>>> list(ip_network('192.0.2.0/24').subnets(new_prefix=26))
[IPv4Network('192.0.2.0/26'), IPv4Network('192.0.2.64/26'),
 IPv4Network('192.0.2.128/26'), IPv4Network('192.0.2.192/26')]
>>> list(ip_network('192.0.2.0/24').subnets(new_prefix=23))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    raise ValueError('new prefix must be longer')
ValueError: new prefix must be longer
>>> list(ip_network('192.0.2.0/24').subnets(new_prefix=25))
[IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/25')]

supernet(prefixlen_diff=1, new_prefix=None)

인자 값에 따라, 이 네트워크 정의를 포함하는 슈퍼 네트. prefixlen_diff는 우리의 접두사 길이를 줄여야 하는 양입니다. new_prefix는 슈퍼 네트의 원하는 새 접두사입니다; 우리의 접두사보다 작아야 합니다. prefixlen_diff와 new_prefix 중 하나만 설정해야 합니다. 단일 네트워크 객체를 반환합니다.

>>> ip_network('192.0.2.0/24').supernet()
IPv4Network('192.0.2.0/23')
>>> ip_network('192.0.2.0/24').supernet(prefixlen_diff=2)
IPv4Network('192.0.0.0/22')
>>> ip_network('192.0.2.0/24').supernet(new_prefix=20)
IPv4Network('192.0.0.0/20')

subnet_of(other)

이 네트워크가 other의 서브 네트이면 True를 반환합니다.

>>> a = ip_network('192.168.1.0/24')
>>> b = ip_network('192.168.1.128/30')
>>> b.subnet_of(a)
True

Added in version 3.7.

supernet_of(other)

이 네트워크가 other의 슈퍼 네트이면 True를 반환합니다.

>>> a = ip_network('192.168.1.0/24')
>>> b = ip_network('192.168.1.128/30')
>>> a.supernet_of(b)
True

Added in version 3.7.

compare_networks(other)

이 네트워크를 other와 비교합니다. 이 비교에서는 네트워크 주소 만 고려됩니다; 호스트 비트는 고려하지 않습니다. -1, 0 또는 1을 반환합니다.

>>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.2/32'))
-1
>>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.0/32'))
1
>>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.1/32'))
0

버전 3.7부터 폐지됨: “<”, “==” 및 “>”와 같은 순서와 비교 알고리즘을 사용합니다.

class ipaddress.IPv6Network(address, strict=True)

IPv6 네트워크 정의를 구성합니다. address는 다음 중 하나일 수 있습니다:

IP 주소와 선택적 접두사 길이로 구성되고 슬래시(/)로 구분된 문자열. IP 주소는 네트워크 주소이며, 접두사 길이는 단일 숫자인 접두사여야 합니다. 접두사 길이가 제공되지 않으면, /128로 간주합니다.

Note that currently expanded netmasks are not supported. That means 2001:db00::0/24 is a valid argument while 2001:db00::0/ffff:ff00:: is not.

128비트에 맞는 정수. 이는 네트워크 주소가 address이고 마스크가 /128인 단일 주소 네트워크와 동등합니다.

길이가 16인 bytes 객체에 채워진 정수, 빅 엔디안. 해석은 정수 address와 유사합니다.

A two-tuple of an address description and a netmask, where the address description is either a string, a 128-bits integer, a 16-bytes packed integer, or an existing IPv6Address object; and the netmask is an integer representing the prefix length.

address가 유효한 IPv6 주소가 아니면 AddressValueError 가 발생합니다. 마스크가 IPv6 주소에 유효하지 않으면 NetmaskValueError 가 발생합니다.

strict가 True이고 제공된 address에 호스트 비트가 설정되면, ValueError가 발생합니다. 그렇지 않으면, 적절한 네트워크 주소를 결정하기 위해 호스트 비트가 마스크 되어 제거됩니다.

버전 3.5에서 변경: address 생성자 매개 변수에 대해 2-튜플 형식을 추가했습니다.

version

max_prefixlen

is_multicast

is_private

is_unspecified

is_reserved

is_loopback

is_link_local

network_address

broadcast_address

hostmask

netmask

with_prefixlen

compressed

exploded

with_netmask

with_hostmask

num_addresses

prefixlen

hosts()

네트워크에서 사용 가능한 호스트에 대한 이터레이터를 반환합니다. 사용 가능한 호스트는 서브 네트 라우터 애니 캐스트 주소를 제외하고 네트워크에 속하는 모든 IP 주소입니다. 마스크 길이가 127인 네트워크의 경우, 서브 네트 라우터 애니 캐스트 주소도 결과에 포함됩니다. 마스크가 128인 네트워크는 단일 호스트 주소가 포함된 리스트를 반환합니다.

overlaps(other)

address_exclude(network)

subnets(prefixlen_diff=1, new_prefix=None)

supernet(prefixlen_diff=1, new_prefix=None)

subnet_of(other)

supernet_of(other)

compare_networks(other)

IPv4Network 의 해당 어트리뷰트 설명서를 참조하십시오.

is_site_local

This attribute is true for the network as a whole if it is true for both the network address and the broadcast address.

연산자

네트워크 객체는 일부 연산자를 지원합니다. 달리 명시하지 않는 한, 연산자는 호환 가능한 객체 간에만 적용할 수 있습니다 (즉 IPv4와 IPv4, IPv6와 IPv6).

논리 연산자

네트워크 객체는 일반적인 논리 연산자 집합으로 비교할 수 있습니다. 네트워크 객체는 먼저 네트워크 주소로 정렬된 다음, 네트 마스크로 정렬됩니다.

이터레이션

네트워크에 속하는 모든 주소를 나열하기 위해 네트워크 객체를 이터레이트 할 수 있습니다. 이터레이션의 경우, 사용 불가능한 호스트를 포함하여 모든 호스트가 반환됩니다 (사용 가능한 호스트의 경우는 hosts() 메서드를 사용하십시오). 예:

>>> for addr in IPv4Network('192.0.2.0/28'):
...     addr
...
IPv4Address('192.0.2.0')
IPv4Address('192.0.2.1')
IPv4Address('192.0.2.2')
IPv4Address('192.0.2.3')
IPv4Address('192.0.2.4')
IPv4Address('192.0.2.5')
IPv4Address('192.0.2.6')
IPv4Address('192.0.2.7')
IPv4Address('192.0.2.8')
IPv4Address('192.0.2.9')
IPv4Address('192.0.2.10')
IPv4Address('192.0.2.11')
IPv4Address('192.0.2.12')
IPv4Address('192.0.2.13')
IPv4Address('192.0.2.14')
IPv4Address('192.0.2.15')

주소 컨테이너로서의 네트워크

네트워크 객체는 주소의 컨테이너 역할을 할 수 있습니다. 몇 가지 예:

>>> IPv4Network('192.0.2.0/28')[0]
IPv4Address('192.0.2.0')
>>> IPv4Network('192.0.2.0/28')[15]
IPv4Address('192.0.2.15')
>>> IPv4Address('192.0.2.6') in IPv4Network('192.0.2.0/28')
True
>>> IPv4Address('192.0.3.6') in IPv4Network('192.0.2.0/28')
False

인터페이스 객체

인터페이스 객체는 해시 가능해서 딕셔너리에서 키로 사용할 수 있습니다.

class ipaddress.IPv4Interface(address)

IPv4 인터페이스를 구성합니다. address의 의미는 임의의 호스트 주소가 항상 허용된다는 점을 제외하고는 IPv4Network 의 생성자와 같습니다.

IPv4Interface는 IPv4Address 의 서브 클래스이기 때문에, 그 클래스의 모든 어트리뷰트를 상속합니다. 또한, 다음과 같은 어트리뷰트를 사용할 수 있습니다:

ip

네트워크 정보가 없는 주소 (IPv4Address).

>>> interface = IPv4Interface('192.0.2.5/24')
>>> interface.ip
IPv4Address('192.0.2.5')

network

이 인터페이스가 속한 네트워크 (IPv4Network).

>>> interface = IPv4Interface('192.0.2.5/24')
>>> interface.network
IPv4Network('192.0.2.0/24')

with_prefixlen

접두사 표기법의 마스크를 갖는 인터페이스의 문자열 표현.

>>> interface = IPv4Interface('192.0.2.5/24')
>>> interface.with_prefixlen
'192.0.2.5/24'

with_netmask

네트워크를 네트 마스크로 사용하는 인터페이스의 문자열 표현.

>>> interface = IPv4Interface('192.0.2.5/24')
>>> interface.with_netmask
'192.0.2.5/255.255.255.0'

with_hostmask

네트워크를 호스트 마스크로 사용하는 인터페이스의 문자열 표현.

>>> interface = IPv4Interface('192.0.2.5/24')
>>> interface.with_hostmask
'192.0.2.5/0.0.0.255'

class ipaddress.IPv6Interface(address)

IPv6 인터페이스를 구성합니다. address의 의미는 임의의 호스트 주소가 항상 허용된다는 점을 제외하고는 IPv6Network 의 생성자와 같습니다.

IPv6Interface는 IPv6Address 의 서브 클래스이기 때문에, 그 클래스의 모든 어트리뷰트를 상속합니다. 또한, 다음과 같은 어트리뷰트를 사용할 수 있습니다:

ip

network

with_prefixlen

with_netmask

with_hostmask

IPv4Interface 의 해당 어트리뷰트 설명서를 참조하십시오.

연산자

인터페이스 객체는 일부 연산자를 지원합니다. 달리 명시하지 않는 한, 연산자는 호환 가능한 객체 간에만 적용할 수 있습니다 (즉 IPv4와 IPv4, IPv6와 IPv6).

논리 연산자

인터페이스 객체는 일반적인 논리 연산자 집합으로 비교할 수 있습니다.

동등 비교(==과 !=)의 경우, 같다고 비교되려면 IP 주소와 네트워크가 같아야 합니다. 인터페이스는 주소나 네트워크 객체와 같다고 비교되지 않습니다.

순서(<, > 등)의 경우 규칙이 다릅니다. 같은 IP 버전의 인터페이스와 주소 객체를 비교할 수 있으며, 주소 객체는 항상 인터페이스 객체보다 앞에 정렬됩니다. 두 개의 인터페이스 객체는 먼저 네트워크로 비교되고, 같으면 IP 주소로 비교됩니다.

다른 모듈 수준 함수

이 모듈은 다음과 같은 모듈 수준 함수도 제공합니다:

ipaddress.v4_int_to_packed(address)

네트워크 (빅 엔디안) 순서로 채워진 길이 4인 바이트열로 주소를 표현합니다. address는 IPv4 IP 주소의 정수 표현입니다. 정수가 음수이거나 너무 커서 IPv4 IP 주소가 될 수 없으면 ValueError가 발생합니다.

>>> ipaddress.ip_address(3221225985)
IPv4Address('192.0.2.1')
>>> ipaddress.v4_int_to_packed(3221225985)
b'\xc0\x00\x02\x01'

ipaddress.v6_int_to_packed(address)

네트워크 (빅 엔디안) 순서로 채워진 길이 16인 바이트열로 주소를 나타냅니다. address는 IPv6 IP 주소의 정수 표현입니다. 정수가 음수이거나 너무 커서 IPv6 IP 주소가 될 수 없으면 ValueError가 발생합니다.

ipaddress.summarize_address_range(first, last)

첫 번째와 마지막 IP 주소가 주어진 요약된 네트워크 범위의 이터레이터를 반환합니다. first는 범위의 첫 번째 IPv4Address 나 IPv6Address 이고 last는 범위의 마지막 IPv4Address 나 IPv6Address입니다. first나 last가 IP 주소가 아니거나, 같은 버전이 아니면 TypeError가 발생합니다. last가 first보다 크지 않거나 first 주소 버전이 4나 6이 아니면 ValueError가 발생합니다.

>>> [ipaddr for ipaddr in ipaddress.summarize_address_range(
...    ipaddress.IPv4Address('192.0.2.0'),
...    ipaddress.IPv4Address('192.0.2.130'))]
[IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/31'), IPv4Network('192.0.2.130/32')]

ipaddress.collapse_addresses(addresses)

Return an iterator of the collapsed IPv4Network or IPv6Network objects. addresses is an iterable of IPv4Network or IPv6Network objects. A TypeError is raised if addresses contains mixed version objects.

>>> [ipaddr for ipaddr in
... ipaddress.collapse_addresses([ipaddress.IPv4Network('192.0.2.0/25'),
... ipaddress.IPv4Network('192.0.2.128/25')])]
[IPv4Network('192.0.2.0/24')]

ipaddress.get_mixed_type_key(obj)

네트워크와 주소를 정렬하기에 적합한 키를 반환합니다. 주소와 네트워크 객체는 기본적으로 정렬할 수 없습니다; 이들은 근본적으로 달라서, 다음과 같은 표현은:

IPv4Address('192.0.2.0') <= IPv4Network('192.0.2.0/24')

doesn’t make sense. There are some times however, where you may wish to have ipaddress sort these anyway. If you need to do this, you can use this function as the key argument to sorted().

obj는 네트워크나 주소 객체입니다.

맞춤 예외

클래스 생성자의 더욱 구체적인 에러 보고를 지원하기 위해, 모듈은 다음 예외를 정의합니다:

exception ipaddress.AddressValueError(ValueError)

주소와 관련된 모든 값 에러.

exception ipaddress.NetmaskValueError(ValueError)

네트 마스크와 관련된 모든 값 에러.

멀티미디어 서비스

이 장에서 설명하는 모듈은 주로 멀티미디어 응용 프로그램에 유용한 다양한 알고리즘 또는 인터페이스를 구현합니다. 가용성은 설치에 달려있습니다. 다음은 개요입니다:

wave — Read and write WAV files

open()

Error

Wave_read 객체

Wave_read

close()

getnchannels()

getsampwidth()

getframerate()

getnframes()

getcomptype()

getcompname()

getparams()

readframes()

rewind()

getmarkers()

getmark()

setpos()

tell()

Wave_write 객체

Wave_write

close()

setnchannels()

setsampwidth()

setframerate()

setnframes()

setcomptype()

setparams()

tell()

writeframesraw()

writeframes()

colorsys — Conversions between color systems

rgb_to_yiq()

yiq_to_rgb()

rgb_to_hls()

hls_to_rgb()

rgb_to_hsv()

hsv_to_rgb()

wave — Read and write WAV files

소스 코드: Lib/wave.py [https://github.com/python/cpython/tree/main/Lib/wave.py]

The wave module provides a convenient interface to the Waveform Audio “WAVE” (or “WAV”) file format. Only uncompressed PCM encoded wave files are supported.

버전 3.12에서 변경: Support for WAVE_FORMAT_EXTENSIBLE headers was added, provided that the extended format is KSDATAFORMAT_SUBTYPE_PCM.

wave 모듈은 다음 함수와 예외를 정의합니다:

wave.open(file, mode=None)

file이 문자열이면, 그 이름의 파일을 엽니다, 그렇지 않으면 파일류 객체로 처리합니다. mode는 다음 중 하나일 수 있습니다:

'rb'

읽기 전용 모드.

'wb'

쓰기 전용 모드.

WAV 파일의 읽기와 쓰기를 동시에 허락하지 않음에 유의하십시오.

'rb' mode는 Wave_read 객체를 반환하고, 'wb' mode는 Wave_write 객체를 반환합니다. mode가 생략되고, 파일류 객체가 file로 전달되면, file.mode가 mode의 기본값으로 사용됩니다.

If you pass in a file-like object, the wave object will not close it when its close() method is called; it is the caller’s responsibility to close the file object.

The open() function may be used in a with statement. When the with block completes, the Wave_read.close() or Wave_write.close() method is called.

버전 3.4에서 변경: 위치 변경할 수 없는(unseekable) 파일에 대한 지원이 추가되었습니다.

exception wave.Error

WAV 명세를 위반하거나 구현 결함으로 인해 무언가가 불가능할 때 발생하는 에러.

Wave_read 객체

class wave.Wave_read

Read a WAV file.

open()이 반환하는, Wave_read 객체는 다음과 같은 메서드를 가지고 있습니다:

close()

스트림이 wave에 의해 열렸다면 스트림을 닫고, 인스턴스를 사용할 수 없게 만듭니다. 이것은 객체가 가비지 수집될 때 자동으로 호출됩니다.

getnchannels()

오디오 채널 수를 반환합니다 (모노는 1, 스테레오는 2).

getsampwidth()

샘플 폭을 바이트 단위로 반환합니다.

getframerate()

샘플링 빈도를 반환합니다.

getnframes()

오디오 프레임의 수를 반환합니다.

getcomptype()

압축 유형을 반환합니다 (지원되는 유형은 'NONE' 뿐입니다).

getcompname()

getcomptype()의 사람이 읽을 수 있는 버전. 보통 'not compressed'이 'NONE'에 해당합니다.

getparams()

Returns a namedtuple() (nchannels, sampwidth, framerate, nframes, comptype, compname), equivalent to output of the get*() methods.

readframes(n)

최대 n 프레임의 오디오를 bytes 객체로 읽고 반환합니다.

rewind()

파일 포인터를 오디오 스트림의 시작 부분으로 되감습니다.

The following two methods are defined for compatibility with the old aifc module, and don’t do anything interesting.

getmarkers()

None을 반환합니다.

Deprecated since version 3.13, will be removed in version 3.15: The method only existed for compatibility with the aifc module which has been removed in Python 3.13.

getmark(id)

에러를 발생시킵니다.

Deprecated since version 3.13, will be removed in version 3.15: The method only existed for compatibility with the aifc module which has been removed in Python 3.13.

다음의 두 메서드는 이들 사이에서 호환 가능한 용어 “위치(position)”를 정의하며, 그 외에는 구현에 따라 다릅니다.

setpos(pos)

파일 포인터를 지정된 위치로 설정합니다.

tell()

현재 파일 포인터 위치를 반환합니다.

Wave_write 객체

class wave.Wave_write

Write a WAV file.

Wave_write objects, as returned by open().

For seekable output streams, the wave header will automatically be updated to reflect the number of frames actually written. For unseekable streams, the nframes value must be accurate when the first frame data is written. An accurate nframes value can be achieved either by calling setnframes() or setparams() with the number of frames that will be written before close() is called and then using writeframesraw() to write the frame data, or by calling writeframes() with all of the frame data to be written. In the latter case writeframes() will calculate the number of frames in the data and set nframes accordingly before writing the frame data.

버전 3.4에서 변경: 위치 변경할 수 없는(unseekable) 파일에 대한 지원이 추가되었습니다.

Wave_write objects have the following methods:

close()

nframes를 올바르게 만들고, 파일이 wave로 열렸으면 파일을 닫습니다. 이 메서드는 객체가 가비지 수집될 때 호출됩니다. 출력 스트림이 위치 변경할 수 없고 nframes가 실제로 기록된 프레임 수와 일치하지 않으면 예외를 일으킵니다.

setnchannels(n)

채널 수를 설정합니다.

setsampwidth(n)

샘플 폭을 n 바이트로 설정합니다.

setframerate(n)

프레임 속도를 n으로 설정합니다.

버전 3.2에서 변경: 이 메서드에 대한 비 정수 입력은 가장 가까운 정수로 자리 올림 됩니다.

setnframes(n)

프레임 수를 n으로 설정합니다. 실제로 쓴 프레임 수가 다르면 나중에 변경됩니다 (이 변경 시도는 출력 스트림이 위치 변경할 수 없으면 에러를 발생시킵니다).

setcomptype(type, name)

압축 유형과 설명을 설정합니다. 현재, 압축 유형 NONE 만 지원됩니다. 즉, 압축하지 않습니다.

setparams(tuple)

The tuple should be (nchannels, sampwidth, framerate, nframes, comptype, compname), with values valid for the set*() methods. Sets all parameters.

tell()

파일의 현재 위치를 반환하는데, Wave_read.tell() 과 Wave_read.setpos() 메서드와 같은 면책 조항이 적용됩니다.

writeframesraw(data)

nframes를 수정하지 않고 오디오 프레임을 씁니다.

버전 3.4에서 변경: 이제 모든 바이트열류 객체가 허락됩니다.

writeframes(data)

오디오 프레임을 기록하고 nframes를 올바르게 만듭니다. 출력 스트림이 위치 변경할 수 없고 data를 기록한 후에 기록된 총 프레임 수가 nframes에 대해 이전에 설정된 값과 일치하지 않으면 에러가 발생시킵니다.

버전 3.4에서 변경: 이제 모든 바이트열류 객체가 허락됩니다.

writeframes()나 writeframesraw()를 호출한 후 파라미터를 설정하는 것이 유효하지 않고, 이를 시도하면 wave.Error가 발생함에 유의하십시오.

colorsys — Conversions between color systems

소스 코드: Lib/colorsys.py [https://github.com/python/cpython/tree/main/Lib/colorsys.py]

The colorsys module defines bidirectional conversions of color values between colors expressed in the RGB (Red Green Blue) color space used in computer monitors and three other coordinate systems: YIQ, HLS (Hue Lightness Saturation) and HSV (Hue Saturation Value). Coordinates in all of these color spaces are floating-point values. In the YIQ space, the Y coordinate is between 0 and 1, but the I and Q coordinates can be positive or negative. In all other spaces, the coordinates are all between 0 and 1.

더 보기

색 공간에 대한 자세한 내용은 https://poynton.ca/ColorFAQ.html 와 https://www.cambridgeincolour.com/tutorials/color-spaces.htm 에서 확인할 수 있습니다.

colorsys 모듈은 다음 함수를 정의합니다:

colorsys.rgb_to_yiq(r, g, b)

RGB 좌표에서 YIQ 좌표로 색을 변환합니다.

colorsys.yiq_to_rgb(y, i, q)

YIQ 좌표에서 RGB 좌표로 색을 변환합니다.

colorsys.rgb_to_hls(r, g, b)

RGB 좌표에서 HLS 좌표로 색을 변환합니다.

colorsys.hls_to_rgb(h, l, s)

HLS 좌표에서 RGB 좌표로 색을 변환합니다.

colorsys.rgb_to_hsv(r, g, b)

RGB 좌표에서 HSV 좌표로 색을 변환합니다.

colorsys.hsv_to_rgb(h, s, v)

HSV 좌표에서 RGB 좌표로 색을 변환합니다.

예:

>>> import colorsys
>>> colorsys.rgb_to_hsv(0.2, 0.4, 0.4)
(0.5, 0.5, 0.4)
>>> colorsys.hsv_to_rgb(0.5, 0.5, 0.4)
(0.2, 0.4, 0.4)

국제화

이 장에서 설명하는 모듈은 프로그램 메시지에 사용할 언어를 선택하거나 현지 규칙에 맞게 출력을 조정할 수 있는 메커니즘을 제공하여 언어 및 로케일에 종속되지 않는 소프트웨어를 작성하는 데 도움이 됩니다.

이 장에서 설명하는 모듈 목록은 다음과 같습니다:

gettext — Multilingual internationalization services

GNU gettext API

bindtextdomain()

textdomain()

gettext()

dgettext()

ngettext()

dngettext()

pgettext()

dpgettext()

npgettext()

dnpgettext()

클래스 기반 API

find()

translation()

install()

NullTranslations 클래스

NullTranslations

_parse()

add_fallback()

gettext()

ngettext()

pgettext()

npgettext()

info()

charset()

install()

GNUTranslations 클래스

GNUTranslations

gettext()

ngettext()

pgettext()

npgettext()

Solaris 메시지 카탈로그 지원

Catalog 생성자

프로그램과 모듈의 국제화

모듈 현지화

응용 프로그램 현지화

실행 중 언어 변경

지연된 번역

감사의 말

locale — Internationalization services

Error

setlocale()

localeconv()

nl_langinfo()

CODESET

D_T_FMT

D_FMT

T_FMT

T_FMT_AMPM

DAY_1

DAY_2

DAY_3

DAY_4

DAY_5

DAY_6

DAY_7

ABDAY_1

ABDAY_2

ABDAY_3

ABDAY_4

ABDAY_5

ABDAY_6

ABDAY_7

MON_1

MON_2

MON_3

MON_4

MON_5

MON_6

MON_7

MON_8

MON_9

MON_10

MON_11

MON_12

ABMON_1

ABMON_2

ABMON_3

ABMON_4

ABMON_5

ABMON_6

ABMON_7

ABMON_8

ABMON_9

ABMON_10

ABMON_11

ABMON_12

RADIXCHAR

THOUSEP

YESEXPR

NOEXPR

CRNCYSTR

ERA

ERA_D_T_FMT

ERA_D_FMT

ERA_T_FMT

ALT_DIGITS

getdefaultlocale()

getlocale()

getpreferredencoding()

getencoding()

normalize()

strcoll()

strxfrm()

format_string()

currency()

str()

delocalize()

localize()

atof()

atoi()

LC_CTYPE

LC_COLLATE

LC_TIME

LC_MONETARY

LC_MESSAGES

LC_NUMERIC

LC_ALL

CHAR_MAX

배경, 세부 사항, 힌트, 팁 및 경고

확장 작성자와 파이썬을 내장하는 프로그램의 경우

메시지 카탈로그에 액세스

gettext()

dgettext()

dcgettext()

textdomain()

bindtextdomain()

bind_textdomain_codeset()

gettext — Multilingual internationalization services

소스 코드: Lib/gettext.py [https://github.com/python/cpython/tree/main/Lib/gettext.py]

gettext 모듈은 파이썬 모듈과 응용 프로그램을 위한 국제화(I18N)와 현지화(L10N) 서비스를 제공합니다. GNU gettext 메시지 카탈로그 API와 파이썬 파일에 더 적합한 고수준 클래스 기반 API를 모두 지원합니다. 아래 설명된 인터페이스를 사용하면 모듈과 응용 프로그램 메시지를 하나의 자연어로 작성하고, 다른 자연어로 실행하기 위해 번역된 메시지 카탈로그를 제공할 수 있습니다.

파이썬 모듈과 응용 프로그램을 현지화하는 데 대한 힌트도 제공됩니다.

GNU gettext API

gettext 모듈은 GNU gettext API와 매우 유사한 다음 API를 정의합니다. 이 API를 사용하면 전체 응용 프로그램의 번역에 전역적으로 영향을 미칩니다. 응용 프로그램이 단일 언어라면 사용자의 로케일에 따라 언어를 선택할 수 있는 것과 함께 종종 이것이 여러분이 원하는 것입니다. 파이썬 모듈을 현지화하거나, 응용 프로그램에서 언어를 실행 중에 전환해야 한다면, 아마도 클래스 기반 API를 대신 사용하고 싶을 것입니다.

gettext.bindtextdomain(domain, localedir=None)

domain을 로케일 디렉터리 localedir에 바인드합니다. 보다 구체적으로, gettext는 경로 (유닉스에서) localedir/language/LC_MESSAGES/domain.mo를 사용하여 지정된 도메인(domain)에 대한 바이너리 .mo 파일을 찾습니다. 여기서 language는 환경 변수 LANGUAGE, LC_ALL, LC_MESSAGES 및 LANG에서 각각 검색됩니다.

localedir이 생략되거나 None이면, domain에 대한 현재 바인딩이 반환됩니다. [1]

gettext.textdomain(domain=None)

현재 전역 도메인을 변경하거나 조회합니다. domain이 None이면, 현재 전역 도메인이 반환되고, 그렇지 않으면 전역 도메인이 domain으로 설정되어 반환됩니다.

gettext.gettext(message)

Return the localized translation of message, based on the current global domain, language, and locale directory. This function is usually aliased as _() in the local namespace (see examples below).

gettext.dgettext(domain, message)

gettext()와 비슷하지만, 지정된 domain에서 메시지를 찾습니다.

gettext.ngettext(singular, plural, n)

gettext()와 비슷하지만, 복수형(plural forms)을 고려합니다. 번역이 발견되면, 복수 공식을 n에 적용하고, 결과 메시지를 반환합니다 (일부 언어는 복수형이 두 개 이상입니다). 번역이 없으면, n이 1이면 singular를 반환합니다; 그렇지 않으면 plural을 반환합니다.

복수 공식은 카탈로그 헤더에서 취합니다. 자유 변수 n을 갖는 C나 파이썬 표현식입니다. 이 표현식은 카탈로그에서 복수의 인덱스로 평가됩니다. .po 파일에 사용되는 정확한 문법과 다양한 언어의 공식은 GNU gettext 설명서 [https://www.gnu.org/software/gettext/manual/gettext.html]를 참조하십시오.

gettext.dngettext(domain, singular, plural, n)

ngettext()와 비슷하지만, 지정된 domain에서 메시지를 찾습니다.

gettext.pgettext(context, message)

gettext.dpgettext(domain, context, message)

gettext.npgettext(context, singular, plural, n)

gettext.dnpgettext(domain, context, singular, plural, n)

접두사에 p가 없는 해당 함수(즉, gettext(), dgettext(), ngettext(), dngettext())와 유사하지만, 번역은 지정된 메시지 context로 제한됩니다.

Added in version 3.8.

Note that GNU gettext also defines a dcgettext() method, but this was deemed not useful and so it is currently unimplemented.

이 API의 일반적인 사용 예는 다음과 같습니다:

import gettext
gettext.bindtextdomain('myapplication', '/path/to/my/language/directory')
gettext.textdomain('myapplication')
_ = gettext.gettext
# ...
print(_('This is a translatable string.'))

클래스 기반 API

The class-based API of the gettext module gives you more flexibility and greater convenience than the GNU gettext API. It is the recommended way of localizing your Python applications and modules. gettext defines a GNUTranslations class which implements the parsing of GNU .mo format files, and has methods for returning strings. Instances of this class can also install themselves in the built-in namespace as the function _().

gettext.find(domain, localedir=None, languages=None, all=False)

이 함수는 표준 .mo 파일 검색 알고리즘을 구현합니다. textdomain()이 취하는 것과 동일한 domain을 취합니다. 선택적 localedir은 bindtextdomain()에서와 같습니다. 선택적 languages는 문자열 리스트이며, 각 문자열은 언어 코드입니다.

localedir이 제공되지 않으면, 기본 시스템 로케일 디렉터리가 사용됩니다. [2] languages가 제공되지 않으면, 다음과 같은 환경 변수가 검색됩니다: LANGUAGE, LC_ALL, LC_MESSAGES 및 LANG. 비어 있지 않은 값을 반환하는 첫 번째 것이 languages 변수에 사용됩니다. 환경 변수는 콜론으로 구분된 언어 목록을 포함해야 하며, 콜론에서 분할되어 예상되는 언어 코드 문자열 리스트를 생성합니다.

그런 다음 find()는 언어를 확장하고 정규화한 다음, 다음 구성 요소로 구성된 기존 파일을 검색하면서, 이들을 이터레이트 합니다:

localedir/language/LC_MESSAGES/domain.mo

존재하는 첫 번째 파일 이름이 find()에 의해 반환됩니다. 그러한 파일이 없으면, None이 반환됩니다. all이 제공되면, 언어 리스트나 환경 변수에 나타나는 순서대로 모든 파일 이름의 리스트를 반환합니다.

gettext.translation(domain, localedir=None, languages=None, class_=None, fallback=False)

Return a *Translations instance based on the domain, localedir, and languages, which are first passed to find() to get a list of the associated .mo file paths. Instances with identical .mo file names are cached. The actual class instantiated is class_ if provided, otherwise GNUTranslations. The class’s constructor must take a single file object argument.

여러 파일이 발견되면, 이후 파일은 이전 파일에 대한 폴 백으로 사용됩니다. 폴 백을 설정하는 것을 허락하기 위해, copy.copy()를 사용하여 캐시에서 각 번역 객체를 복제합니다; 실제 인스턴스 데이터는 여전히 캐시와 공유됩니다.

.mo 파일이 없으면, 이 함수는 fallback이 거짓(기본값)이면 OSError를 발생시키고, fallback이 참이면 NullTranslations 인스턴스를 반환합니다.

버전 3.3에서 변경: IOError used to be raised, it is now an alias of OSError.

버전 3.11에서 변경: codeset parameter is removed.

gettext.install(domain, localedir=None, *, names=None)

This installs the function _() in Python’s builtins namespace, based on domain and localedir which are passed to the function translation().

names 매개 변수에 대해서는, 번역 객체의 install() 메서드에 대한 설명을 참조하십시오.

As seen below, you usually mark the strings in your application that are candidates for translation, by wrapping them in a call to the _() function, like this:

print(_('This string will be translated.'))

For convenience, you want the _() function to be installed in Python’s builtins namespace, so it is easily accessible in all modules of your application.

버전 3.11에서 변경: names is now a keyword-only parameter.

NullTranslations 클래스

번역 클래스는 원본 소스 파일 메시지 문자열을 번역된 메시지 문자열로 실제로 구현합니다. 모든 번역 클래스에서 사용하는 베이스 클래스는 NullTranslations입니다; 여러분 자신의 특수화된 번역 클래스를 작성하는 데 사용할 수 있는 기본 인터페이스를 제공합니다. NullTranslations의 메서드는 다음과 같습니다:

class gettext.NullTranslations(fp=None)

베이스 클래스에서 무시되는, 선택적인 파일 객체 fp를 취합니다. 파생 클래스에 의해 설정되는 “보호되는” 인스턴스 변수 _info와 _charset 뿐만 아니라 add_fallback()을 통해 설정되는 _fallback을 초기화합니다. 그런 다음 fp가 None이 아니면 self._parse(fp)를 호출합니다.

_parse(fp)

베이스 클래스에서 아무런 일도 하지 않는 이 메서드는 파일 객체 fp를 취하고, 이 파일에서 데이터를 읽고, 메시지 카탈로그를 초기화합니다. 지원되지 않는 메시지 카탈로그 파일 형식이 있으면, 이 메서드를 재정의하여 형식을 구문 분석해야 합니다.

add_fallback(fallback)

현재 번역 객체의 폴 백 객체로 fallback을 추가합니다. 주어진 메시지에 대한 번역을 제공할 수 없으면 번역 개체는 폴 백을 참조해야 합니다.

gettext(message)

폴 백이 설정되었으면, gettext()를 폴 백으로 전달합니다. 그렇지 않으면, message를 반환합니다. 파생 클래스에서 재정의됩니다.

ngettext(singular, plural, n)

폴 백이 설정되었으면, ngettext()를 폴 백으로 전달합니다. 그렇지 않으면, n이 1이면 singular를 반환합니다; 그렇지 않으면 plural을 반환합니다. 파생 클래스에서 재정의됩니다.

pgettext(context, message)

폴 백이 설정되었으면, pgettext()를 폴 백으로 전달합니다. 그렇지 않으면, 번역된 메시지를 반환합니다. 파생 클래스에서 재정의됩니다.

Added in version 3.8.

npgettext(context, singular, plural, n)

폴 백이 설정되었으면, npgettext()를 폴 백으로 전달합니다. 그렇지 않으면, 번역된 메시지를 반환합니다. 파생 클래스에서 재정의됩니다.

Added in version 3.8.

info()

Return a dictionary containing the metadata found in the message catalog file.

charset()

메시지 카탈로그 파일의 인코딩을 반환합니다.

install(names=None)

이 메서드는 gettext()를 내장 이름 공간에 설치하여, _에 연결합니다.

If the names parameter is given, it must be a sequence containing the names of functions you want to install in the builtins namespace in addition to _(). Supported names are 'gettext', 'ngettext', 'pgettext', and 'npgettext'.

Note that this is only one way, albeit the most convenient way, to make the _() function available to your application. Because it affects the entire application globally, and specifically the built-in namespace, localized modules should never install _(). Instead, they should use this code to make _() available to their module:

import gettext
t = gettext.translation('mymodule', ...)
_ = t.gettext

This puts _() only in the module’s global namespace and so only affects calls within this module.

버전 3.8에서 변경: 'pgettext'와 'npgettext'를 추가했습니다.

GNUTranslations 클래스

The gettext module provides one additional class derived from NullTranslations: GNUTranslations. This class overrides _parse() to enable reading GNU gettext format .mo files in both big-endian and little-endian format.

GNUTranslations parses optional metadata out of the translation catalog. It is convention with GNU gettext to include metadata as the translation for the empty string. This metadata is in RFC 822 [https://datatracker.ietf.org/doc/html/rfc822.html]-style key: value pairs, and should contain the Project-Id-Version key. If the key Content-Type is found, then the charset property is used to initialize the “protected” _charset instance variable, defaulting to None if not found. If the charset encoding is specified, then all message ids and message strings read from the catalog are converted to Unicode using this encoding, else ASCII is assumed.

Since message ids are read as Unicode strings too, all *gettext() methods will assume message ids as Unicode strings, not byte strings.

The entire set of key/value pairs are placed into a dictionary and set as the “protected” _info instance variable.

.mo 파일의 매직 번호가 유효하지 않거나, 주 버전 번호가 예상치 못한 값이거나, 파일을 읽는 동안 다른 문제가 발생하면 GNUTranslations 클래스를 인스턴스 화할 때 OSError가 발생할 수 있습니다.

class gettext.GNUTranslations

베이스 클래스 구현에서 다음 메서드가 재정의되었습니다:

gettext(message)

카탈로그에서 message id를 찾아 해당 메시지 문자열을 유니코드 문자열로 반환합니다. 카탈로그에 message id에 대한 항목이 없고, 폴 백이 설정되었으면, 조회는 폴 백의 gettext() 메서드로 전달됩니다. 그렇지 않으면, message id가 반환됩니다.

ngettext(singular, plural, n)

메시지 id의 복수형 조회를 수행합니다. singular는 카탈로그에서 찾기 위해 메시지 id로 사용되는 반면, n은 사용할 복수형을 결정하는 데 사용됩니다. 반환된 메시지 문자열은 유니코드 문자열입니다.

카탈로그에서 메시지 id를 찾을 수 없고, 폴 백이 지정되었으면, 요청은 폴 백의 ngettext() 메서드로 전달됩니다. 그렇지 않으면, n이 1이면 singular가 반환되고, 다른 모든 경우에는 plural이 반환됩니다.

예를 들면 다음과 같습니다:

n = len(os.listdir('.'))
cat = GNUTranslations(somefile)
message = cat.ngettext(
    'There is %(num)d file in this directory',
    'There are %(num)d files in this directory',
    n) % {'num': n}

pgettext(context, message)

카탈로그에서 context와 message id를 찾아 해당 메시지 문자열을 유니코드 문자열로 반환합니다. 카탈로그에 message id와 context에 대한 항목이 없고, 폴 백이 설정되었으면, 조회는 폴 백의 pgettext() 메서드로 전달됩니다. 그렇지 않으면, message id가 반환됩니다.

Added in version 3.8.

npgettext(context, singular, plural, n)

메시지 ID의 복수형 조회를 수행합니다. singular는 카탈로그에서 찾기 위해 메시지 id로 사용되는 반면, n은 사용할 복수형을 결정하는 데 사용됩니다.

context의 메시지 id가 카탈로그에 없고, 폴 백이 지정되었으면, 요청은 폴 백의 npgettext() 메서드로 전달됩니다. 그렇지 않으면, n이 1이면 singular가 반환되고, 다른 모든 경우에는 plural이 반환됩니다.

Added in version 3.8.

Solaris 메시지 카탈로그 지원

Solaris 운영 체제는 자체 바이너리 .mo 파일 형식을 정의하지만, 이 형식에 대한 설명서를 찾을 수 없어서, 현재 지원되지 않습니다.

Catalog 생성자

GNOME은 James Henstridge의 gettext 모듈 버전을 사용하지만, 이 버전은 API가 약간 다릅니다. 설명된 사용법은 다음과 같습니다:

import gettext
cat = gettext.Catalog(domain, localedir)
_ = cat.gettext
print(_('hello world'))

For compatibility with this older module, the function Catalog() is an alias for the translation() function described above.

이 모듈과 Henstridge 버전의 한 가지 차이점: 그의 카탈로그 객체는 매핑 API를 통한 액세스를 지원했지만, 사용되지 않는 것으로 보여서 현재 지원되지 않습니다.

프로그램과 모듈의 국제화

국제화(I18N)는 프로그램이 여러 언어를 인식하도록 하는 작업을 말합니다. 현지화(L10N)는 일단 국제화된 프로그램이 현지 언어와 문화적 습관에 적응하는 것을 말합니다. 파이썬 프로그램에 다국어 메시지를 제공하려면, 다음 단계를 수행해야 합니다:

번역 가능한 문자열을 특별히 표시하여 프로그램이나 모듈을 준비합니다

표시된 파일에 대해 도구 모음을 실행하여 원시 메시지 카탈로그를 생성합니다

메시지 카탈로그의 언어별 번역을 만듭니다

메시지 문자열이 올바르게 번역되도록 gettext 모듈을 사용합니다

In order to prepare your code for I18N, you need to look at all the strings in your files. Any string that needs to be translated should be marked by wrapping it in _('...') — that is, a call to the function _. For example:

filename = 'mylog.txt'
message = _('writing a log message')
with open(filename, 'w') as fp:
    fp.write(message)

이 예에서, 문자열 'writing a log message'는 번역 후보로 표시되지만, 문자열 'mylog.txt'와 'w'는 그렇지 않습니다.

There are a few tools to extract the strings meant for translation. The original GNU gettext only supported C or C++ source code but its extended version xgettext scans code written in a number of languages, including Python, to find strings marked as translatable. Babel [https://babel.pocoo.org/] is a Python internationalization library that includes a pybabel script to extract and compile message catalogs. François Pinard’s program called xpot does a similar job and is available as part of his po-utils package [https://github.com/pinard/po-utils].

(파이썬에는 pygettext.py와 msgfmt.py라고 하는 이러한 프로그램의 순수 파이썬 버전도 포함되어 있습니다; 일부 파이썬 배포판은 이 프로그램들을 설치합니다. pygettext.py는 xgettext와 유사하지만, 파이썬 소스 코드만 이해하며 C나 C++ 와 같은 다른 프로그래밍 언어를 처리할 수 없습니다. pygettext.py는 xgettext와 유사한 명령 줄 인터페이스를 지원합니다; 사용에 대한 자세한 내용을 보려면, pygettext.py --help를 실행하십시오. msgfmt.py는 GNU msgfmt와 바이너리 호환됩니다. 이 두 프로그램을 사용하면, 파이썬 응용 프로그램을 국제화하기 위해 GNU gettext 패키지가 필요하지 않을 수 있습니다.)

xgettext, pygettext 및 유사한 도구는 메시지 카탈로그인 .po 파일을 생성합니다. 이 파일은 소스 코드에 표시된 모든 문자열과 이러한 문자열의 번역된 버전에 대한 자리를 포함하는 사람이 읽을 수 있는 파일입니다.

이 .po 파일의 사본은 지원되는 모든 자연어에 대한 번역을 작성하는 개별 인간 번역가에게 전달됩니다. 완성된 언어별 버전을 <language-name>.po 파일로 다시 보내고, 이는 msgfmt 프로그램을 사용하여 기계가 읽을 수 있는 .mo 바이너리 카탈로그 파일로 컴파일됩니다. .mo 파일은 실행 시간에 실제 번역 처리를 위해 gettext 모듈에서 사용됩니다.

코드에서 gettext 모듈을 사용하는 방법은 단일 모듈을 국제화하는지 또는 전체 응용 프로그램을 국제화하는지에 따라 다릅니다. 다음 두 섹션에서는 각 사례에 관해 설명합니다.

모듈 현지화

모듈을 현지화한다면, 전역적인 변경을 가하지 않도록 주의해야 합니다, 예를 들어, 내장 이름 공간. GNU gettext API 대신 클래스 기반 API를 사용해야 합니다.

모듈이 “spam”이고 모듈의 다양한 자연어 번역 .mo 파일이 /usr/share/locale에 GNU gettext 형식으로 존재한다고 가정해 봅시다. 다음은 모듈 맨 위에 들어갈 내용입니다:

import gettext
t = gettext.translation('spam', '/usr/share/locale')
_ = t.gettext

응용 프로그램 현지화

If you are localizing your application, you can install the _() function globally into the built-in namespace, usually in the main driver file of your application. This will let all your application-specific files just use _('...') without having to explicitly install it in each file.

간단한 경우에는, 응용 프로그램의 메인 드라이버 파일에 다음 코드만 추가하면 됩니다:

import gettext
gettext.install('myapplication')

로케일 디렉터리를 설정해야 하면, install() 함수로 전달할 수 있습니다:

import gettext
gettext.install('myapplication', '/usr/share/locale')

실행 중 언어 변경

프로그램에서 동시에 여러 언어를 지원해야 하면, 다음과 같은 식으로 여러 번역 인스턴스를 만든 다음 명시적으로 전환할 수 있습니다:

import gettext

lang1 = gettext.translation('myapplication', languages=['en'])
lang2 = gettext.translation('myapplication', languages=['fr'])
lang3 = gettext.translation('myapplication', languages=['de'])

# start by using language1
lang1.install()

# ... time goes by, user selects language 2
lang2.install()

# ... more time goes by, user selects language 3
lang3.install()

지연된 번역

대부분의 코딩 상황에서, 문자열은 코딩된 위치에서 번역됩니다. 그러나 때때로, 번역을 위해 문자열을 표시하지만, 실제 번역을 뒤로 연기할 필요가 있습니다. 전형적인 예는 다음과 같습니다:

animals = ['mollusk',
           'albatross',
           'rat',
           'penguin',
           'python', ]
# ...
for a in animals:
    print(a)

여기서, animals 리스트의 문자열을 번역 가능한 것으로 표시하려고 하지만, 실제로 인쇄될 때까지 번역하고 싶지는 않습니다.

이 상황을 처리 할 수 있는 한 가지 방법은 다음과 같습니다:

def _(message): return message

animals = [_('mollusk'),
           _('albatross'),
           _('rat'),
           _('penguin'),
           _('python'), ]

del _

# ...
for a in animals:
    print(_(a))

This works because the dummy definition of _() simply returns the string unchanged. And this dummy definition will temporarily override any definition of _() in the built-in namespace (until the del command). Take care, though if you have a previous definition of _() in the local namespace.

Note that the second use of _() will not identify “a” as being translatable to the gettext program, because the parameter is not a string literal.

이를 처리하는 다른 방법은 다음 예제를 사용하는 것입니다:

def N_(message): return message

animals = [N_('mollusk'),
           N_('albatross'),
           N_('rat'),
           N_('penguin'),
           N_('python'), ]

# ...
for a in animals:
    print(_(a))

In this case, you are marking translatable strings with the function N_(), which won’t conflict with any definition of _(). However, you will need to teach your message extraction program to look for translatable strings marked with N_(). xgettext, pygettext, pybabel extract, and xpot all support this through the use of the -k command-line switch. The choice of N_() here is totally arbitrary; it could have just as easily been MarkThisStringForTranslation().

감사의 말

다음 분들은 이 모듈을 만드는 데 코드, 피드백, 디자인 제안, 이전 구현 및 귀중한 경험을 제공했습니다:

Peter Funk

James Henstridge

Juan David Ibáñez Palomar

Marc-André Lemburg

Martin von Löwis

François Pinard

Barry Warsaw

Gustavo Niemeyer

각주

[1]

The default locale directory is system dependent; for example, on Red Hat Linux it is /usr/share/locale, but on Solaris it is /usr/lib/locale. The gettext module does not try to support these system dependent defaults; instead its default is sys.base_prefix/share/locale (see sys.base_prefix). For this reason, it is always best to call bindtextdomain() with an explicit absolute path at the start of your application.

[2]

위의 bindtextdomain()에 대한 각주를 참조하십시오.

locale — Internationalization services

소스 코드: Lib/locale.py [https://github.com/python/cpython/tree/main/Lib/locale.py]

locale 모듈은 POSIX 로케일 데이터베이스와 기능에 대한 액세스를 엽니다. POSIX 로케일 메커니즘은 프로그래머가 소프트웨어가 실행되는 국가별로 모든 세부 사항을 알 필요 없이 응용 프로그램에서 특정 문화적 문제를 다룰 수 있도록 합니다.

The locale module is implemented on top of the _locale module, which in turn uses an ANSI C locale implementation if available.

locale 모듈은 다음 예외와 함수를 정의합니다:

exception locale.Error

setlocale()에 전달된 로케일이 인식되지 않을 때 발생하는 예외.

locale.setlocale(category, locale=None)

locale이 제공되고 None이 아니면, setlocale()은 category의 로케일 설정을 수정합니다. 사용 가능한 범주는 아래 데이터 설명에 나열되어 있습니다. locale은 문자열이거나 두 개의 문자열(언어 코드와 인코딩)의 이터러블일 수 있습니다. 이터러블이면, 로케일 에일리어싱 엔진을 사용하여 로케일 이름으로 변환됩니다. 빈 문자열은 사용자의 기본 설정을 지정합니다. 로케일 수정에 실패하면, 예외 Error가 발생합니다. 성공하면, 새 로케일 설정이 반환됩니다.

locale이 생략되거나 None이면, category의 현재 설정이 반환됩니다.

setlocale()은 대부분의 시스템에서 스레드 안전하지 않습니다. 응용 프로그램은 보통 다음과 같은 호출로 시작합니다

import locale
locale.setlocale(locale.LC_ALL, '')

이는 모든 범주의 로케일을 사용자의 기본 설정(보통 LANG 환경 변수에서 지정됩니다)으로 설정합니다. 그 후에 로케일을 변경하지 않으면, 다중 스레딩을 사용해도 문제가 발생하지 않습니다.

locale.localeconv()

현지 규칙의 데이터베이스를 딕셔너리로 반환합니다. 이 딕셔너리에는 키로 다음 문자열이 있습니다:

범주

키

의미

LC_NUMERIC

'decimal_point'

십진수 소수점 문자.

'grouping'

'thousands_sep'가 예상되는 상대 위치를 지정하는 숫자의 시퀀스. 시퀀스가 CHAR_MAX로 종료되면, 더 이상의 그룹화가 수행되지 않습니다. 시퀀스가 0으로 종료되면, 마지막 그룹 크기가 반복적으로 사용됩니다.

'thousands_sep'

그룹 간에 사용되는 문자.

LC_MONETARY

'int_curr_symbol'

국제 통화 기호.

'currency_symbol'

현지 통화 기호.

'p_cs_precedes/n_cs_precedes'

통화 기호가 값 앞에 오는지 여부 (각각 양과 음의 값).

'p_sep_by_space/n_sep_by_space'

통화 기호가 스페이스로 값과 구분되는지 여부 (각각 양과 음의 값).

'mon_decimal_point'

화폐값에 사용되는 십진수 소수점.

'frac_digits'

화폐값의 현지 형식에 사용되는 소수점 이하 자릿수.

'int_frac_digits'

화폐값의 국제 형식에 사용되는 소수점 이하 자릿수.

'mon_thousands_sep'

화폐값에 사용되는 그룹 구분자.

'mon_grouping'

'grouping'과 동등합니다, 화폐값에 사용됩니다.

'positive_sign'

양의 화폐값을 표현하는 데 사용되는 기호.

'negative_sign'

음의 화폐값을 표현하는 데 사용되는 기호.

'p_sign_posn/n_sign_posn'

부호의 위치 (각각 양과 음의 값), 아래를 참조하십시오.

모든 숫자 값은 이 로케일에서 아무런 값도 지정되지 않았음을 나타내는 CHAR_MAX로 설정할 수 있습니다.

'p_sign_posn'과 'n_sign_posn'에 가능한 값은 다음과 같습니다.

값

설명

0

통화와 값을 괄호로 묶습니다.

1

부호는 값과 통화 기호 앞에 와야 합니다.

2

부호는 값과 통화 기호 뒤에 와야 합니다.

3

부호는 값 바로 앞에 와야 합니다.

4

부호는 값 바로 뒤에 와야 합니다.

CHAR_MAX

이 로케일에 지정된 것이 없습니다.

The function temporarily sets the LC_CTYPE locale to the LC_NUMERIC locale or the LC_MONETARY locale if locales are different and numeric or monetary strings are non-ASCII. This temporary change affects other threads.

버전 3.7에서 변경: The function now temporarily sets the LC_CTYPE locale to the LC_NUMERIC locale in some cases.

locale.nl_langinfo(option)

로케일 특정 정보를 문자열로 반환합니다. 이 함수를 모든 시스템에서 사용할 수 있는 것은 아니며, 가능한 옵션 집합은 플랫폼마다 다를 수 있습니다. 가능한 인자 값은 숫자이며, locale 모듈에 있는 기호 상수를 사용할 수 있습니다.

nl_langinfo() 함수는 다음 키 중 하나를 받아들입니다. 대부분의 설명은 GNU C 라이브러리의 해당 설명에서 가져옵니다.

locale.CODESET

선택한 로케일에 사용된 문자 인코딩의 이름으로 문자열을 가져옵니다.

locale.D_T_FMT

로케일 특정 방식으로 날짜와 시간을 표시하기 위해 time.strftime()의 포맷 문자열로 사용할 수 있는 문자열을 가져옵니다.

locale.D_FMT

로케일 특정 방식으로 날짜를 표시하기 위해 time.strftime()의 포맷 문자열로 사용할 수 있는 문자열을 가져옵니다.

locale.T_FMT

로케일 특정 방식으로 시간을 표시하기 위해 time.strftime()의 포맷 문자열로 사용할 수 있는 문자열을 가져옵니다.

locale.T_FMT_AMPM

am/pm 형식으로 시간을 나타내는 time.strftime()의 포맷 문자열을 가져옵니다.

locale.DAY_1

locale.DAY_2

locale.DAY_3

locale.DAY_4

locale.DAY_5

locale.DAY_6

locale.DAY_7

주의 n 번째 날의 이름을 가져옵니다.

참고

이것은 월요일이 주의 첫 번째 요일인 국제관례(ISO 8601)가 아니라, DAY_1이 일요일인 미국 관례를 따릅니다.

locale.ABDAY_1

locale.ABDAY_2

locale.ABDAY_3

locale.ABDAY_4

locale.ABDAY_5

locale.ABDAY_6

locale.ABDAY_7

주의 n 번째 날의 줄인 이름을 가져옵니다.

locale.MON_1

locale.MON_2

locale.MON_3

locale.MON_4

locale.MON_5

locale.MON_6

locale.MON_7

locale.MON_8

locale.MON_9

locale.MON_10

locale.MON_11

locale.MON_12

n 번째 달의 이름을 가져옵니다.

locale.ABMON_1

locale.ABMON_2

locale.ABMON_3

locale.ABMON_4

locale.ABMON_5

locale.ABMON_6

locale.ABMON_7

locale.ABMON_8

locale.ABMON_9

locale.ABMON_10

locale.ABMON_11

locale.ABMON_12

n 번째 달의 줄인 이름을 가져옵니다.

locale.RADIXCHAR

기수 문자(십진수 점, 십진수 쉼표, 등)를 가져옵니다.

locale.THOUSEP

천 단위 (3자리 그룹) 구분자 문자를 가져옵니다.

locale.YESEXPR

예/아니요 질문에 대한 긍정적인 응답을 인식하기 위해 regex 함수에 사용할 수 있는 정규식을 가져옵니다.

locale.NOEXPR

Get a regular expression that can be used with the regex(3) function to recognize a negative response to a yes/no question.

참고

The regular expressions for YESEXPR and NOEXPR use syntax suitable for the regex function from the C library, which might differ from the syntax used in re.

locale.CRNCYSTR

통화 기호를 가져옵니다. 기호가 값 앞에 나타나야 하면 “-”, 기호가 값 뒤에 나타나야 하면 “+”, 또는 기호가 기수 문자를 대체해야 하면 “.”가 앞에 나옵니다.

locale.ERA

Get a string which describes how years are counted and displayed for each era in a locale.

대부분의 로케일은 이 값을 정의하지 않습니다. 이 값을 정의하는 로케일의 예는 일본입니다. 일본에서, 전통적인 날짜 표시에는 당시 군주의 통치에 해당하는 시대의 이름이 포함됩니다.

Normally it should not be necessary to use this value directly. Specifying the E modifier in their format strings causes the time.strftime() function to use this information. The format of the returned string is specified in The Open Group Base Specifications Issue 8, paragraph 7.3.5.2 LC_TIME C-Language Access [https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap07.html#tag_07_03_05_02].

locale.ERA_D_T_FMT

로케일 특정 시대 기반 방식으로 날짜와 시간을 나타내는 time.strftime()의 포맷 문자열을 가져옵니다.

locale.ERA_D_FMT

로케일 특정 시대 기반 방식으로 날짜를 나타내는 time.strftime()의 포맷 문자열을 가져옵니다.

locale.ERA_T_FMT

로케일 특정 시대 기반 방식으로 시간을 나타내는 time.strftime()의 포맷 문자열을 가져옵니다.

locale.ALT_DIGITS

Get a string consisting of up to 100 semicolon-separated symbols used to represent the values 0 to 99 in a locale-specific way. In most locales this is an empty string.

The function temporarily sets the LC_CTYPE locale to the locale of the category that determines the requested value (LC_TIME, LC_NUMERIC, LC_MONETARY or LC_MESSAGES) if locales are different and the resulting string is non-ASCII. This temporary change affects other threads.

버전 3.14에서 변경: The function now temporarily sets the LC_CTYPE locale in some cases.

locale.getdefaultlocale([envvars])

기본 로케일 설정을 판별하려고 시도하고 (language code, encoding) 형식의 튜플로 반환합니다.

POSIX에 따르면, setlocale(LC_ALL, '')을 호출하지 않은 프로그램은 이식성 있는 'C' 로케일을 사용하여 실행됩니다. setlocale(LC_ALL, '')을 호출하면 LANG 변수로 정의된 기본 로케일을 사용하도록 합니다. 현재 로케일 설정을 방해하고 싶지 않기 때문에 위에서 설명한 방식으로 동작을 에뮬레이트 합니다.

다른 플랫폼과의 호환성을 유지하기 위해, LANG 변수뿐만 아니라 envvars 매개 변수로 제공된 변수 리스트도 검사합니다. 가장 먼저 정의된 것으로 발견된 것이 사용됩니다. envvars는 GNU gettext에서 사용되는 검색 경로를 기본값으로 합니다; 항상 변수 이름 'LANG'을 포함해야 합니다. GNU gettext 검색 경로에는 'LC_ALL', 'LC_CTYPE', 'LANG' 및 'LANGUAGE'가 순서대로 포함됩니다.

코드 'C'를 제외하고, 언어 코드는 RFC 1766 [https://datatracker.ietf.org/doc/html/rfc1766.html]에 해당합니다. language code 및 encoding은 그 값을 판별할 수 없으면 None일 수 있습니다.

Deprecated since version 3.11, will be removed in version 3.15.

locale.getlocale(category=LC_CTYPE)

Returns the current setting for the given locale category as sequence containing language code, encoding. category may be one of the LC_* values except LC_ALL. It defaults to LC_CTYPE.

코드 'C'를 제외하고, 언어 코드는 RFC 1766 [https://datatracker.ietf.org/doc/html/rfc1766.html]에 해당합니다. language code 및 encoding은 그 값을 판별할 수 없으면 None일 수 있습니다.

locale.getpreferredencoding(do_setlocale=True)

Return the locale encoding used for text data, according to user preferences. User preferences are expressed differently on different systems, and might not be available programmatically on some systems, so this function only returns a guess.

일부 시스템에서는, 사용자 설정을 얻기 위해 setlocale()을 호출할 필요가 있어서, 이 함수는 스레드 안전하지 않습니다. setlocale을 호출할 필요가 없거나 원하지 않으면, do_setlocale을 False로 설정해야 합니다.

On Android or if the Python UTF-8 Mode is enabled, always return 'utf-8', the locale encoding and the do_setlocale argument are ignored.

The Python preinitialization configures the LC_CTYPE locale. See also the filesystem encoding and error handler.

버전 3.7에서 변경: The function now always returns "utf-8" on Android or if the Python UTF-8 Mode is enabled.

locale.getencoding()

Get the current locale encoding:

On Android and VxWorks, return "utf-8".

On Unix, return the encoding of the current LC_CTYPE locale. Return "utf-8" if nl_langinfo(CODESET) returns an empty string: for example, if the current LC_CTYPE locale is not supported.

On Windows, return the ANSI code page.

The Python preinitialization configures the LC_CTYPE locale. See also the filesystem encoding and error handler.

This function is similar to getpreferredencoding(False) except this function ignores the Python UTF-8 Mode.

Added in version 3.11.

locale.normalize(localename)

주어진 로케일 이름에 대해 정규화된 로케일 코드를 반환합니다. 반환된 로케일 코드는 setlocale()에서 사용하도록 포맷됩니다. 정규화에 실패하면, 원래 이름이 변경되지 않은 상태로 반환됩니다.

주어진 인코딩이 알려지지 않았으면, 함수는 setlocale()처럼 로케일 코드의 기본 인코딩을 기본값으로 사용합니다.

locale.strcoll(string1, string2)

현재 LC_COLLATE 설정에 따라 두 문자열을 비교합니다. 다른 비교 함수처럼, string1이 string2 앞이니 뒤에 오는지 또는 같은지에 따라 음수나 양수 값 또는 0을 반환합니다.

locale.strxfrm(string)

문자열을 로케일을 고려한 비교에 사용할 수 있는 문자열로 변환합니다. 예를 들어, strxfrm(s1) < strxfrm(s2)는 strcoll(s1, s2) < 0과 동등합니다. 이 함수는 같은 문자열이 반복적으로 비교될 때, 예를 들어 문자열 시퀀스를 정렬할 때, 사용할 수 있습니다.

locale.format_string(format, val, grouping=False, monetary=False)

Formats a number val according to the current LC_NUMERIC setting. The format follows the conventions of the % operator. For floating-point values, the decimal point is modified if appropriate. If grouping is True, also takes the grouping into account.

monetary가 참이면, 변환은 화폐 천 단위 구분 기호와 그룹화 문자열을 사용합니다.

format % val에서처럼 포맷 지정자를 처리하지만, 현재 로케일 설정을 고려합니다.

버전 3.7에서 변경: monetary 키워드 매개 변수가 추가되었습니다.

locale.currency(val, symbol=True, grouping=False, international=False)

현재 LC_MONETARY 설정에 따라 숫자 val을 포맷합니다.

The returned string includes the currency symbol if symbol is true, which is the default. If grouping is True (which is not the default), grouping is done with the value. If international is True (which is not the default), the international currency symbol is used.

참고

This function will not work with the ‘C’ locale, so you have to set a locale via setlocale() first.

locale.str(float)

Formats a floating-point number using the same format as the built-in function str(float), but takes the decimal point into account.

locale.delocalize(string)

LC_NUMERIC 설정에 따라, 문자열을 정규화된 숫자 문자열로 변환합니다.

Added in version 3.5.

locale.localize(string, grouping=False, monetary=False)

Converts a normalized number string into a formatted string following the LC_NUMERIC settings.

Added in version 3.10.

locale.atof(string, func=float)

Converts a string to a number, following the LC_NUMERIC settings, by calling func on the result of calling delocalize() on string.

locale.atoi(string)

LC_NUMERIC 규칙에 따라, 문자열을 정수로 변환합니다.

locale.LC_CTYPE

Locale category for the character type functions. Most importantly, this category defines the text encoding, i.e. how bytes are interpreted as Unicode codepoints. See PEP 538 [https://peps.python.org/pep-0538/] and PEP 540 [https://peps.python.org/pep-0540/] for how this variable might be automatically coerced to C.UTF-8 to avoid issues created by invalid settings in containers or incompatible settings passed over remote SSH connections.

Python doesn’t internally use locale-dependent character transformation functions from ctype.h. Instead, an internal pyctype.h provides locale-independent equivalents like Py_TOLOWER.

locale.LC_COLLATE

문자열 정렬을 위한 로케일 범주. locale 모듈의 함수 strcoll()과 strxfrm()이 영향을 받습니다.

locale.LC_TIME

시간 포매팅을 위한 로케일 범주. time.strftime() 함수는 이러한 규칙을 따릅니다.

locale.LC_MONETARY

화폐값의 포매팅을 위한 로케일 범주. 사용 가능한 옵션은 localeconv() 함수에서 제공됩니다.

locale.LC_MESSAGES

메시지 표시를 위한 로케일 범주. 파이썬은 현재 응용 프로그램에 특정한 로케일을 고려한 메시지를 지원하지 않습니다. os.strerror()에서 반환된 메시지처럼 운영 체제에서 표시되는 메시지는 이 범주의 영향을 받을 수 있습니다.

This value may not be available on operating systems not conforming to the POSIX standard, most notably Windows.

locale.LC_NUMERIC

Locale category for formatting numbers. The functions format_string(), atoi(), atof() and str() of the locale module are affected by that category. All other numeric formatting operations are not affected.

locale.LC_ALL

모든 로케일 설정의 조합. 로케일을 변경할 때 이 플래그를 사용하면, 모든 범주에 대한 로케일 설정을 시도합니다. 어떤 범주에서 실패하면, 아무런 범주도 변경되지 않습니다. 이 플래그를 사용하여 로케일을 가져오면, 모든 범주의 설정을 나타내는 문자열이 반환됩니다. 이 문자열은 나중에 설정을 복원하는 데 사용할 수 있습니다.

locale.CHAR_MAX

이것은 localeconv()가 반환한 다른 값에 사용되는 기호 상수입니다.

예:

>>> import locale
>>> loc = locale.getlocale()  # get current locale
# use German locale; name might vary with platform
>>> locale.setlocale(locale.LC_ALL, 'de_DE')
>>> locale.strcoll('f\xe4n', 'foo')  # compare a string containing an umlaut
>>> locale.setlocale(locale.LC_ALL, '')   # use user's preferred locale
>>> locale.setlocale(locale.LC_ALL, 'C')  # use default (C) locale
>>> locale.setlocale(locale.LC_ALL, loc)  # restore saved locale

배경, 세부 사항, 힌트, 팁 및 경고

The C standard defines the locale as a program-wide property that may be relatively expensive to change. On top of that, some implementations are broken in such a way that frequent locale changes may cause core dumps. This makes the locale somewhat painful to use correctly.

처음에, 프로그램이 시작할 때, 사용자가 선호하는 로케일이 무엇이든 로케일은 C 로케일입니다. 한 가지 예외가 있습니다: LC_CTYPE 범주는 시작 시 현재 로케일 인코딩을 사용자가 선호하는 로케일 인코딩으로 설정하도록 변경됩니다. 다른 범주에 대해서는 프로그램이 setlocale(LC_ALL, '')을 호출하여 사용자가 선호하는 로케일 설정을 원한다고 명시적으로 말해야 합니다.

일반적으로 어떤 라이브러리 루틴에서 setlocale()을 호출하는 것은 나쁜 생각입니다. 부작용으로 전체 프로그램에 영향을 미치기 때문입니다. 저장하고 복원하는 것도 거의 비슷하게 나쁩니다: 비용이 많이 들고 설정이 복원되기 전에 실행되는 다른 스레드에 영향을 줍니다.

일반적인 용도로 모듈을 코딩할 때, 로케일에 영향을 받는 로케일 독립적인 버전의 연산(가령 time.strftime()에 사용되는 특정 포맷)이 필요하면, 표준 라이브러리 루틴을 사용하지 않고 수행할 수 있는 방법을 찾아야 합니다. 로케일 설정을 사용하는 것이 좋다고 자신을 설득하는 것이 더 좋습니다. 최후의 수단으로만 모듈이 C가 아닌 로케일 설정과 호환되지 않는다는 것을 문서화해야 합니다.

The only way to perform numeric operations according to the locale is to use the special functions defined by this module: atof(), atoi(), format_string(), str().

로케일에 따라 대소 문자 변환과 문자 분류를 수행할 방법이 없습니다. (유니코드) 텍스트 문자열의 경우 이것은 문자 값으로만 수행되는 반면, 바이트 문자열의 경우, 바이트의 ASCII 값에 따라 수행되고, 높은 비트가 설정된 바이트(즉, ASCII가 아닌 바이트)는 절대 변환되거나 글자나 공백과 같은 문자 클래스의 일부로 고려되지 않습니다.

확장 작성자와 파이썬을 내장하는 프로그램의 경우

확장 모듈은 현재 로케일이 무엇인지 찾는 것을 제외하고는 setlocale()을 호출해서는 안 됩니다. 그러나 반환 값은 이식성 있게 복원하는 데만 사용될 수 있기 때문에, 그다지 유용하지 않습니다 (아마도 로케일이 C인지 아닌지를 확인하는 것은 예외입니다).

When Python code uses the locale module to change the locale, this also affects the embedding application. If the embedding application doesn’t want this to happen, it should remove the _locale extension module (which does all the work) from the table of built-in modules in the config.c file, and make sure that the _locale module is not accessible as a shared library.

메시지 카탈로그에 액세스

locale.gettext(msg)

locale.dgettext(domain, msg)

locale.dcgettext(domain, msg, category)

locale.textdomain(domain)

locale.bindtextdomain(domain, dir)

locale.bind_textdomain_codeset(domain, codeset)

The locale module exposes the C library’s gettext interface on systems that provide this interface. It consists of the functions gettext(), dgettext(), dcgettext(), textdomain(), bindtextdomain(), and bind_textdomain_codeset(). These are similar to the same functions in the gettext module, but use the C library’s binary format for message catalogs, and the C library’s search algorithms for locating message catalogs.

Python applications should normally find no need to invoke these functions, and should use gettext instead. A known exception to this rule are applications that link with additional C libraries which internally invoke C functions gettext or dcgettext. For these applications, it may be necessary to bind the text domain, so that the libraries can properly locate their message catalogs.

프로그램 프레임워크

이 장에서 설명하는 모듈은 주로 프로그램의 구조를 결정하는 프레임워크입니다. 현재 여기에 설명된 모듈은 모두 명령 줄 인터페이스 작성을 지향합니다.

이 장에서 설명하는 모듈의 전체 목록은 다음과 같습니다:

turtle — 터틀 그래픽

소개

Get started

Tutorial

Starting a turtle environment

Basic drawing

펜 제어

The turtle’s position

Making algorithmic patterns

How to…

Get started as quickly as possible

Use the turtle module namespace

Use turtle graphics in a script

Use object-oriented turtle graphics

Turtle graphics reference

Turtle 메서드

TurtleScreen/Screen의 메서드

RawTurtle/Turtl의 메서드와 해당 함수

거북이 움직임

forward()

fd()

back()

bk()

backward()

right()

rt()

left()

lt()

goto()

setpos()

setposition()

teleport()

setx()

sety()

setheading()

seth()

home()

circle()

dot()

stamp()

clearstamp()

clearstamps()

undo()

speed()

거북이의 상태 보고

position()

pos()

towards()

xcor()

ycor()

heading()

distance()

측정 설정

degrees()

radians()

펜 제어

그리기 상태

pendown()

pd()

down()

penup()

pu()

up()

pensize()

width()

pen()

isdown()

색상 제어

pencolor()

fillcolor()

color()

채우기

filling()

begin_fill()

end_fill()

더 많은 그리기 제어

reset()

clear()

write()

거북이 상태

가시성

hideturtle()

ht()

showturtle()

st()

isvisible()

외관

shape()

resizemode()

shapesize()

turtlesize()

shearfactor()

tilt()

tiltangle()

shapetransform()

get_shapepoly()

이벤트 사용하기

onrelease()

ondrag()

특수 Turtle 메서드

begin_poly()

end_poly()

get_poly()

clone()

getturtle()

getpen()

getscreen()

setundobuffer()

undobufferentries()

복합 모양

TurtleScreen/Screen 메서드와 해당 함수

창 제어

bgcolor()

bgpic()

clearscreen()

resetscreen()

screensize()

setworldcoordinates()

애니메이션 제어

delay()

tracer()

update()

화면 이벤트 사용하기

listen()

onkey()

onkeyrelease()

onkeypress()

onclick()

onscreenclick()

ontimer()

mainloop()

done()

입력 메서드

textinput()

numinput()

설정과 특수 메서드

mode()

colormode()

getcanvas()

getshapes()

register_shape()

addshape()

turtles()

window_height()

window_width()

TurtleScreen에서 상속되지 않은, Screen만의 메서드

bye()

exitonclick()

save()

setup()

title()

공개 클래스

RawTurtle

RawPen

Turtle

TurtleScreen

Screen

ScrolledCanvas

Shape

addcomponent()

Vec2D

Explanation

도움말과 구성

도움말 사용법

독스트링을 다른 언어로 번역

write_docstringdict()

Screen과 Turtle을 구성하는 방법

turtledemo — 데모 스크립트

파이썬 2.6 이후의 변화

파이썬 3.0 이후의 변화

cmd — Support for line-oriented command interpreters

Cmd

Cmd 객체

cmdloop()

do_help()

onecmd()

emptyline()

default()

completedefault()

columnize()

precmd()

postcmd()

preloop()

postloop()

prompt

identchars

lastcmd

cmdqueue

intro

doc_header

misc_header

undoc_header

ruler

use_rawinput

Cmd 예

shlex — Simple lexical analysis

split()

join()

quote()

shlex

shlex 객체

get_token()

push_token()

read_token()

sourcehook()

push_source()

pop_source()

error_leader()

commenters

wordchars

whitespace

escape

quotes

escapedquotes

whitespace_split

infile

instream

source

debug

lineno

token

eof

punctuation_chars

구문 분석 규칙

셸과의 호환성 향상

turtle — 터틀 그래픽

소스 코드: Lib/turtle.py [https://github.com/python/cpython/tree/main/Lib/turtle.py]

소개

Turtle graphics is an implementation of the popular geometric drawing tools introduced in Logo [https://en.wikipedia.org/wiki/Turtle_(robot)], developed by Wally Feurzeig, Seymour Papert and Cynthia Solomon in 1967.

Get started

x-y 평면의 (0, 0)에서 출발하는 로봇 거북이를 상상해보십시오. import turtle 후에, turtle.forward(15) 명령을 내리면, 그것이 향한 방향으로 15픽셀 움직이고 (화면에서!), 움직이면서 선을 그립니다. turtle.right(25) 명령을 내려보십시오, 그러면 제자리에서 시계 방향으로 25도 회전합니다.

Turtle star

turtle은 간단한 움직임을 반복하는 프로그램을 사용하여 복잡한 모양을 그릴 수 있습니다.

In Python, turtle graphics provides a representation of a physical “turtle” (a little robot with a pen) that draws on a sheet of paper on the floor.

It’s an effective and well-proven way for learners to encounter programming concepts and interaction with software, as it provides instant, visible feedback. It also provides convenient access to graphical output in general.

Turtle drawing was originally created as an educational tool, to be used by teachers in the classroom. For the programmer who needs to produce some graphical output it can be a way to do that without the overhead of introducing more complex or external libraries into their work.

Tutorial

New users should start here. In this tutorial we’ll explore some of the basics of turtle drawing.

Starting a turtle environment

In a Python shell, import all the objects of the turtle module:

from turtle import *

If you run into a No module named '_tkinter' error, you’ll have to install the Tk interface package on your system.

Basic drawing

Send the turtle forward 100 steps:

forward(100)

You should see (most likely, in a new window on your display) a line drawn by the turtle, heading East. Change the direction of the turtle, so that it turns 120 degrees left (anti-clockwise):

left(120)

Let’s continue by drawing a triangle:

forward(100)
left(120)
forward(100)

Notice how the turtle, represented by an arrow, points in different directions as you steer it.

Experiment with those commands, and also with backward() and right().

펜 제어

Try changing the color - for example, color('blue') - and width of the line - for example, width(3) - and then drawing again.

You can also move the turtle around without drawing, by lifting up the pen: up() before moving. To start drawing again, use down().

The turtle’s position

Send your turtle back to its starting-point (useful if it has disappeared off-screen):

home()

The home position is at the center of the turtle’s screen. If you ever need to know them, get the turtle’s x-y coordinates with:

pos()

Home is at (0, 0).

And after a while, it will probably help to clear the window so we can start anew:

clearscreen()

Making algorithmic patterns

Using loops, it’s possible to build up geometric patterns:

for steps in range(100):
    for c in ('blue', 'red', 'green'):
        color(c)
        forward(steps)
        right(30)

- which of course, are limited only by the imagination!

Let’s draw the star shape at the top of this page. We want red lines, filled in with yellow:

color('red')
fillcolor('yellow')

Just as up() and down() determine whether lines will be drawn, filling can be turned on and off:

begin_fill()

Next we’ll create a loop:

while True:
    forward(200)
    left(170)
    if abs(pos()) < 1:
        break

abs(pos()) < 1 is a good way to know when the turtle is back at its home position.

Finally, complete the filling:

end_fill()

(Note that filling only actually takes place when you give the end_fill() command.)

How to…

This section covers some typical turtle use-cases and approaches.

Get started as quickly as possible

One of the joys of turtle graphics is the immediate, visual feedback that’s available from simple commands - it’s an excellent way to introduce children to programming ideas, with a minimum of overhead (not just children, of course).

The turtle module makes this possible by exposing all its basic functionality as functions, available with from turtle import *. The turtle graphics tutorial covers this approach.

It’s worth noting that many of the turtle commands also have even more terse equivalents, such as fd() for forward(). These are especially useful when working with learners for whom typing is not a skill.

You’ll need to have the Tk interface package installed on your system for turtle graphics to work. Be warned that this is not always straightforward, so check this in advance if you’re planning to use turtle graphics with a learner.

Use the turtle module namespace

Using from turtle import * is convenient - but be warned that it imports a rather large collection of objects, and if you’re doing anything but turtle graphics you run the risk of a name conflict (this becomes even more an issue if you’re using turtle graphics in a script where other modules might be imported).

The solution is to use import turtle - fd() becomes turtle.fd(), width() becomes turtle.width() and so on. (If typing “turtle” over and over again becomes tedious, use for example import turtle as t instead.)

Use turtle graphics in a script

It’s recommended to use the turtle module namespace as described immediately above, for example:

import turtle as t
from random import random

for i in range(100):
    steps = int(random() * 100)
    angle = int(random() * 360)
    t.right(angle)
    t.fd(steps)

Another step is also required though - as soon as the script ends, Python will also close the turtle’s window. Add:

t.mainloop()

to the end of the script. The script will now wait to be dismissed and will not exit until it is terminated, for example by closing the turtle graphics window.

Use object-oriented turtle graphics

더 보기

Explanation of the object-oriented interface

Other than for very basic introductory purposes, or for trying things out as quickly as possible, it’s more usual and much more powerful to use the object-oriented approach to turtle graphics. For example, this allows multiple turtles on screen at once.

In this approach, the various turtle commands are methods of objects (mostly of Turtle objects). You can use the object-oriented approach in the shell, but it would be more typical in a Python script.

The example above then becomes:

from turtle import Turtle
from random import random

t = Turtle()
for i in range(100):
    steps = int(random() * 100)
    angle = int(random() * 360)
    t.right(angle)
    t.fd(steps)

t.screen.mainloop()

Note the last line. t.screen is an instance of the Screen that a Turtle instance exists on; it’s created automatically along with the turtle.

The turtle’s screen can be customised, for example:

t.screen.title('Object-oriented turtle demo')
t.screen.bgcolor("orange")

Turtle graphics reference

참고

다음 설명서에서 함수의 인자 목록이 제공됩니다. 물론 메서드에는 추가의 첫 번째 인자 self가 있으며 여기서는 생략합니다.

Turtle 메서드

거북이 움직임

이동과 그리기

forward() | fd()

backward() | bk() | back()

right() | rt()

left() | lt()

goto() | setpos() | setposition()

teleport()

setx()

sety()

setheading() | seth()

home()

circle()

dot()

stamp()

clearstamp()

clearstamps()

undo()

speed()

거북이의 상태 보고

position() | pos()

towards()

xcor()

ycor()

heading()

distance()

설정과 측정

degrees()

radians()

펜 제어

그리기 상태

pendown() | pd() | down()

penup() | pu() | up()

pensize() | width()

pen()

isdown()

색상 제어

color()

pencolor()

fillcolor()

채우기

filling()

begin_fill()

end_fill()

더 많은 그리기 제어

reset()

clear()

write()

거북이 상태

가시성

showturtle() | st()

hideturtle() | ht()

isvisible()

외관

shape()

resizemode()

shapesize() | turtlesize()

shearfactor()

tiltangle()

tilt()

shapetransform()

get_shapepoly()

이벤트 사용하기

onclick()

onrelease()

ondrag()

특수 Turtle 메서드

begin_poly()

end_poly()

get_poly()

clone()

getturtle() | getpen()

getscreen()

setundobuffer()

undobufferentries()

TurtleScreen/Screen의 메서드

창 제어

bgcolor()

bgpic()

clearscreen()

resetscreen()

screensize()

setworldcoordinates()

애니메이션 제어

delay()

tracer()

update()

화면 이벤트 사용하기

listen()

onkey() | onkeyrelease()

onkeypress()

onclick() | onscreenclick()

ontimer()

mainloop() | done()

설정과 특수 메서드

mode()

colormode()

getcanvas()

getshapes()

register_shape() | addshape()

turtles()

window_height()

window_width()

입력 메서드

textinput()

numinput()

Screen 특정 메서드

bye()

exitonclick()

save()

setup()

title()

RawTurtle/Turtl의 메서드와 해당 함수

이 섹션의 대부분의 예제는 turtle이라는 Turtle 인스턴스를 참조합니다.

거북이 움직임

turtle.forward(distance)

turtle.fd(distance)

매개변수:

distance – 숫자 (정수나 실수)

거북이가 향한 방향으로, 지정된 distance만큼 거북이를 앞으로 움직입니다.

>>> turtle.position()
(0.00,0.00)
>>> turtle.forward(25)
>>> turtle.position()
(25.00,0.00)
>>> turtle.forward(-75)
>>> turtle.position()
(-50.00,0.00)

turtle.back(distance)

turtle.bk(distance)

turtle.backward(distance)

매개변수:

distance – 숫자

거북이가 향한 반대 방향으로, distance만큼 거북이를 뒤로 움직입니다. 거북이의 방향을 바꾸지 않습니다.

>>> turtle.position()
(0.00,0.00)
>>> turtle.backward(30)
>>> turtle.position()
(-30.00,0.00)

turtle.right(angle)

turtle.rt(angle)

매개변수:

angle – 숫자 (정수나 실수)

angle 단위만큼 거북이를 오른쪽으로 회전합니다. (단위는 기본적으로 도(degree)이지만, degrees()와 radians() 함수를 통해 설정할 수 있습니다.) 각도 방향은 거북이 모드에 따라 다릅니다, mode()를 참조하십시오.

>>> turtle.heading()
22.0
>>> turtle.right(45)
>>> turtle.heading()
337.0

turtle.left(angle)

turtle.lt(angle)

매개변수:

angle – 숫자 (정수나 실수)

angle 단위만큼 거북이를 왼쪽으로 회전합니다. (단위는 기본적으로 도(degree)이지만, degrees()와 radians() 함수를 통해 설정할 수 있습니다.) 각도 방향은 거북이 모드에 따라 다릅니다, mode()를 참조하십시오.

>>> turtle.heading()
22.0
>>> turtle.left(45)
>>> turtle.heading()
67.0

turtle.goto(x, y=None)

turtle.setpos(x, y=None)

turtle.setposition(x, y=None)

매개변수:

x – 숫자나 숫자의 쌍/벡터

y – 숫자나 None

y가 None이면, x는 좌표 쌍이거나 Vec2D여야 합니다 (예를 들어 pos()에서 반환된 것과 같은).

거북이를 절대 위치로 움직입니다. 펜이 내려져 있으면, 선을 그립니다. 거북이의 방향을 바꾸지 않습니다.

>>> tp = turtle.pos()
>>> tp
(0.00,0.00)
>>> turtle.setpos(60,30)
>>> turtle.pos()
(60.00,30.00)
>>> turtle.setpos((20,80))
>>> turtle.pos()
(20.00,80.00)
>>> turtle.setpos(tp)
>>> turtle.pos()
(0.00,0.00)

turtle.teleport(x, y=None, *, fill_gap=False)

매개변수:

x – 숫자나 None

y – 숫자나 None

fill_gap – a boolean

Move turtle to an absolute position. Unlike goto(x, y), a line will not be drawn. The turtle’s orientation does not change. If currently filling, the polygon(s) teleported from will be filled after leaving, and filling will begin again after teleporting. This can be disabled with fill_gap=True, which makes the imaginary line traveled during teleporting act as a fill barrier like in goto(x, y).

>>> tp = turtle.pos()
>>> tp
(0.00,0.00)
>>> turtle.teleport(60)
>>> turtle.pos()
(60.00,0.00)
>>> turtle.teleport(y=10)
>>> turtle.pos()
(60.00,10.00)
>>> turtle.teleport(20, 30)
>>> turtle.pos()
(20.00,30.00)

Added in version 3.12.

turtle.setx(x)

매개변수:

x – 숫자 (정수나 실수)

거북이의 첫 번째 좌표를 x로 설정하고, 두 번째 좌표는 변경하지 않습니다.

>>> turtle.position()
(0.00,240.00)
>>> turtle.setx(10)
>>> turtle.position()
(10.00,240.00)

turtle.sety(y)

매개변수:

y – 숫자 (정수나 실수)

거북이의 두 번째 좌표를 y로 설정하고, 첫 번째 좌표는 변경하지 않습니다.

>>> turtle.position()
(0.00,40.00)
>>> turtle.sety(-10)
>>> turtle.position()
(0.00,-10.00)

turtle.setheading(to_angle)

turtle.seth(to_angle)

매개변수:

to_angle – 숫자 (정수나 실수)

거북이의 방향을 to_angle로 설정합니다. 다음은 몇 가지 일반적인 도(degree)로 나타낸 방향입니다:

표준 모드

로고 모드

0 - 동

0 - 북

90 - 북

90 - 동

180 - 서

180 - 남

270 - 남

270 - 서

>>> turtle.setheading(90)
>>> turtle.heading()
90.0

turtle.home()

거북이를 원점 – 좌표 (0,0) – 으로 이동하고 방향을 시작 방향으로 설정합니다 (모드에 따라 다릅니다, mode()를 참조하십시오).

>>> turtle.heading()
90.0
>>> turtle.position()
(0.00,-10.00)
>>> turtle.home()
>>> turtle.position()
(0.00,0.00)
>>> turtle.heading()
0.0

turtle.circle(radius, extent=None, steps=None)

매개변수:

radius – 숫자

extent – 숫자 (또는 None)

steps – 정수 (또는 None)

주어진 반지름(radius)으로 원을 그립니다. 중심은 거북이 왼쪽으로 radius 단위입니다; extent – 각도 – 는 원의 어느 부분이 그려지는지를 결정합니다. extent가 주어지지 않으면, 전체 원을 그립니다. extent가 완전한 원이 아니면, 호의 한 끝점이 현재 펜 위치입니다. radius가 양수면 시계 반대 방향으로, 그렇지 않으면 시계 방향으로 호를 그립니다. 마지막으로 거북이의 방향이 extent만큼 변경됩니다.

원은 내접하는 정다각형으로 근사되므로, steps가 사용할 단계 수를 결정합니다. 제공하지 않으면, 자동으로 계산됩니다. 정다각형을 그리는 데 사용할 수 있습니다.

>>> turtle.home()
>>> turtle.position()
(0.00,0.00)
>>> turtle.heading()
0.0
>>> turtle.circle(50)
>>> turtle.position()
(-0.00,0.00)
>>> turtle.heading()
0.0
>>> turtle.circle(120, 180)  # draw a semicircle
>>> turtle.position()
(0.00,240.00)
>>> turtle.heading()
180.0

turtle.dot(size=None, *color)

매개변수:

size – 정수 >= 1 (주어지면)

color – 색상 문자열이나 숫자 색상 튜플

color를 사용하여 지름이 size인 원형 점을 그립니다. size가 제공되지 않으면, pensize+4와 2*pensize 중 큰 값이 사용됩니다.

>>> turtle.home()
>>> turtle.dot()
>>> turtle.fd(50); turtle.dot(20, "blue"); turtle.fd(50)
>>> turtle.position()
(100.00,-0.00)
>>> turtle.heading()
0.0

turtle.stamp()

거북이 모양의 사본을 현재 거북이 위치에서 캔버스에 찍습니다. 해당 스탬프에 대한 stamp_id를 반환하는데, clearstamp(stamp_id)를 호출하여 스탬프를 삭제하는 데 사용할 수 있습니다.

>>> turtle.color("blue")
>>> stamp_id = turtle.stamp()
>>> turtle.fd(50)

turtle.clearstamp(stampid)

매개변수:

stampid – 정수, 이전 stamp() 호출의 반환 값이어야 합니다

지정된 stampid의 스탬프를 삭제합니다.

>>> turtle.position()
(150.00,-0.00)
>>> turtle.color("blue")
>>> astamp = turtle.stamp()
>>> turtle.fd(50)
>>> turtle.position()
(200.00,-0.00)
>>> turtle.clearstamp(astamp)
>>> turtle.position()
(200.00,-0.00)

turtle.clearstamps(n=None)

매개변수:

n – 정수 (또는 None)

거북이 스탬프의 전부나 처음/마지막 n 개를 삭제합니다. n이 None이면, 모든 스탬프를 삭제합니다, n > 0 이면 처음 n 스탬프를 삭제하고, n < 0 이면 마지막 n 스탬프를 삭제합니다.

>>> for i in range(8):
...     unused_stamp_id = turtle.stamp()
...     turtle.fd(30)
>>> turtle.clearstamps(2)
>>> turtle.clearstamps(-2)
>>> turtle.clearstamps()

turtle.undo()

마지막 거북이의 행동을 (반복적으로) 되돌립니다. 되돌릴 수 있는 행동의 수는 언두버퍼(undobuffer)의 크기에 따라 결정됩니다.

>>> for i in range(4):
...     turtle.fd(50); turtle.lt(80)
...
>>> for i in range(8):
...     turtle.undo()

turtle.speed(speed=None)

매개변수:

speed – 0..10 범위의 정수나 속도 문자열 (아래를 참조하십시오)

거북이의 속도를 0..10 범위의 정숫값으로 설정합니다. 인자가 없으면, 현재 속도를 반환합니다.

입력이 10보다 크거나 0.5보다 작은 숫자면, 속도는 0으로 설정됩니다. 속도 문자열은 다음과 같이 속도 값에 매핑됩니다:

“fastest”: 0

“fast”: 10

“normal”: 6

“slow”: 3

“slowest”: 1

1에서 10까지의 속도는 선 그리기와 거북이 회전의 애니메이션이 점점 더 빨라집니다.

주의: speed = 0 은 애니메이션이 발생하지 않음을 의미합니다. forward/back은 거북이가 점프하게 만들고 마찬가지로 left/right는 거북이가 순간적으로 방향을 바꾸게 만듭니다.

>>> turtle.speed()
3
>>> turtle.speed('normal')
>>> turtle.speed()
6
>>> turtle.speed(9)
>>> turtle.speed()
9

거북이의 상태 보고

turtle.position()

turtle.pos()

거북이의 현재 위치 (x, y)를 (Vec2D 벡터로) 반환합니다.

>>> turtle.pos()
(440.00,-0.00)

turtle.towards(x, y=None)

매개변수:

x – 숫자 또는 숫자 쌍/벡터 또는 거북이 인스턴스

y – x가 숫자면 숫자, 그렇지 않으면 None

거북이 위치에서 (x, y), 벡터 또는 다른 거북이로 지정된 위치로의 선과의 각도를 반환합니다. 이것은 거북이의 시작 방향에 따라 다른데, 이는 모드에 따라 다릅니다 - “standard”/”world” 또는 “logo”.

>>> turtle.goto(10, 10)
>>> turtle.towards(0,0)
225.0

turtle.xcor()

거북이의 x 좌표를 반환합니다.

>>> turtle.home()
>>> turtle.left(50)
>>> turtle.forward(100)
>>> turtle.pos()
(64.28,76.60)
>>> print(round(turtle.xcor(), 5))
64.27876

turtle.ycor()

거북이의 y 좌표를 반환합니다.

>>> turtle.home()
>>> turtle.left(60)
>>> turtle.forward(100)
>>> print(turtle.pos())
(50.00,86.60)
>>> print(round(turtle.ycor(), 5))
86.60254

turtle.heading()

거북이의 현재 방향을 반환합니다 (값은 거북이 모드에 따라 다릅니다. mode()를 참조하십시오).

>>> turtle.home()
>>> turtle.left(67)
>>> turtle.heading()
67.0

turtle.distance(x, y=None)

매개변수:

x – 숫자 또는 숫자 쌍/벡터 또는 거북이 인스턴스

y – x가 숫자면 숫자, 그렇지 않으면 None

거북이에서 (x, y), 주어진 벡터 또는 주어진 다른 거북이까지의 거리를 거북이 단계 단위로 반환합니다.

>>> turtle.home()
>>> turtle.distance(30,40)
50.0
>>> turtle.distance((30,40))
50.0
>>> joe = Turtle()
>>> joe.forward(77)
>>> turtle.distance(joe)
77.0

측정 설정

turtle.degrees(fullcircle=360.0)

매개변수:

fullcircle – 숫자

각도 측정 단위를 설정합니다, 즉 전체 원에 대한 “도(degrees)”의 수를 설정합니다. 기본값은 360도입니다.

>>> turtle.home()
>>> turtle.left(90)
>>> turtle.heading()
90.0

Change angle measurement unit to grad (also known as gon,
grade, or gradian and equals 1/100-th of the right angle.)
>>> turtle.degrees(400.0)
>>> turtle.heading()
100.0
>>> turtle.degrees(360)
>>> turtle.heading()
90.0

turtle.radians()

각도 측정 단위를 라디안으로 설정합니다. degrees(2*math.pi)와 동등합니다.

>>> turtle.home()
>>> turtle.left(90)
>>> turtle.heading()
90.0
>>> turtle.radians()
>>> turtle.heading()
1.5707963267948966

펜 제어

그리기 상태

turtle.pendown()

turtle.pd()

turtle.down()

펜을 내립니다 – 움직일 때 그립니다.

turtle.penup()

turtle.pu()

turtle.up()

펜을 올립니다 – 움직일 때 그리지 않습니다.

turtle.pensize(width=None)

turtle.width(width=None)

매개변수:

width – 양수

선 두께를 width로 설정하거나 반환합니다. 크기 조정 모드(resizemode)가 “auto”로 설정되고 거북이 모양(shape)이 다각형이면, 해당 다각형은 같은 선 두께로 그려집니다. 인자가 없으면, 현재 펜 크기가 반환됩니다.

>>> turtle.pensize()
1
>>> turtle.pensize(10)   # from here on lines of width 10 are drawn

turtle.pen(pen=None, **pendict)

매개변수:

pen – 아래 나열된 키 중 일부나 전부가 포함된 딕셔너리

pendict – 아래에 나열된 키를 키워드로 사용하는 하나 이상의 키워드 인자

다음 키/값 쌍으로 “펜 딕셔너리”에 있는 펜의 속성을 반환하거나 설정합니다:

“shown”: True/False

“pendown”: True/False

“pencolor”: 색상 문자열이나 색상 튜플

“fillcolor”: 색상 문자열이나 색상 튜플

“pensize”: 양수

“speed”: 0..10 범위의 숫자

“resizemode”: “auto” 또는 “user” 또는 “noresize”

“stretchfactor”: (양수, 양수)

“outline”: 양수

“tilt”: 숫자

이 딕셔너리는 이전 펜 상태를 복원하기 위해 pen()의 후속 호출에 대한 인자로 사용될 수 있습니다. 또한 이러한 속성 중 하나 이상을 키워드 인자로 제공할 수 있습니다. 하나의 문장에서 여러 펜 속성을 설정하는 데 사용할 수 있습니다.

>>> turtle.pen(fillcolor="black", pencolor="red", pensize=10)
>>> sorted(turtle.pen().items())
[('fillcolor', 'black'), ('outline', 1), ('pencolor', 'red'),
 ('pendown', True), ('pensize', 10), ('resizemode', 'noresize'),
 ('shearfactor', 0.0), ('shown', True), ('speed', 9),
 ('stretchfactor', (1.0, 1.0)), ('tilt', 0.0)]
>>> penstate=turtle.pen()
>>> turtle.color("yellow", "")
>>> turtle.penup()
>>> sorted(turtle.pen().items())[:3]
[('fillcolor', ''), ('outline', 1), ('pencolor', 'yellow')]
>>> turtle.pen(penstate, fillcolor="green")
>>> sorted(turtle.pen().items())[:3]
[('fillcolor', 'green'), ('outline', 1), ('pencolor', 'red')]

turtle.isdown()

펜이 내려가 있으면 True를, 올라가 있으면 False를 반환합니다.

>>> turtle.penup()
>>> turtle.isdown()
False
>>> turtle.pendown()
>>> turtle.isdown()
True

색상 제어

turtle.pencolor(*args)

펜 색상(pencolor)을 반환하거나 설정합니다.

네 가지 입력 형식이 허용됩니다:

pencolor()

현재 펜 색상을 색상 지정 문자열이나 튜플로 반환합니다 (예를 참조하십시오). 다른 color/pencolor/fillcolor 호출에 대한 입력으로 사용될 수 있습니다.

pencolor(colorstring)

펜 색상을 "red", "yellow" 또는 "#33cc8c"와 같은 Tk 색상 지정 문자열인 colorstring으로 설정합니다.

pencolor((r, g, b))

펜 색상을 r, g 및 b의 튜플로 표현되는 RGB 색상으로 설정합니다. r, g 및 b 각각은 0..colormode 범위에 있어야 합니다. 여기서 colormode는 1.0이나 255입니다 (colormode()를 참조하십시오).

pencolor(r, g, b)

펜 색상을 r, g 및 b로 표현되는 RGB 색상으로 설정합니다. r, g 및 b는 각각 0..colormode 범위에 있어야 합니다.

거북이 모양이 다각형이면, 해당 다각형의 외곽선은 새로 설정된 펜 색상으로 그려집니다.

>>> colormode()
1.0
>>> turtle.pencolor()
'red'
>>> turtle.pencolor("brown")
>>> turtle.pencolor()
'brown'
>>> tup = (0.2, 0.8, 0.55)
>>> turtle.pencolor(tup)
>>> turtle.pencolor()
(0.2, 0.8, 0.5490196078431373)
>>> colormode(255)
>>> turtle.pencolor()
(51.0, 204.0, 140.0)
>>> turtle.pencolor('#32c18f')
>>> turtle.pencolor()
(50.0, 193.0, 143.0)

turtle.fillcolor(*args)

채우기 색상(fillcolor)을 반환하거나 설정합니다.

네 가지 입력 형식이 허용됩니다:

fillcolor()

현재 채우기 색상을 색상 지정 문자열로 (튜플 형식으로도 가능합니다) 반환합니다 (예를 참조하십시오). 다른 color/pencolor/fillcolor 호출에 대한 입력으로 사용될 수 있습니다.

fillcolor(colorstring)

채우기 색상을 "red", "yellow" 또는 "#33cc8c"와 같은 Tk 색상 지정 문자열인 colorstring으로 설정합니다.

fillcolor((r, g, b))

채우기 색상을 r, g 및 b의 튜플로 표현되는 RGB 색상으로 설정합니다. r, g 및 b 각각은 0..colormode 범위에 있어야 합니다. 여기서 colormode는 1.0이나 255입니다 (colormode()를 참조하십시오).

fillcolor(r, g, b)

채우기 색상을 r, g 및 b로 표현되는 RGB 색상으로 설정합니다. r, g 및 b는 각각 0..colormode 범위에 있어야 합니다.

거북이 모양이 다각형이면, 해당 다각형의 내부는 새로 설정된 채우기 색상으로 그려집니다.

>>> turtle.fillcolor("violet")
>>> turtle.fillcolor()
'violet'
>>> turtle.pencolor()
(50.0, 193.0, 143.0)
>>> turtle.fillcolor((50, 193, 143))  # Integers, not floats
>>> turtle.fillcolor()
(50.0, 193.0, 143.0)
>>> turtle.fillcolor('#ffffff')
>>> turtle.fillcolor()
(255.0, 255.0, 255.0)

turtle.color(*args)

펜 색상과 채우기 색상을 반환하거나 설정합니다.

몇 가지 입력 형식이 허용됩니다. 다음과 같이 0에서 3개의 인자를 사용합니다:

color()

pencolor()와 fillcolor()에 의해 반환된 현재 펜 색상과 현재 채우기 색상을 한 쌍의 색 지정 문자열이나 튜플로 반환합니다.

color(colorstring), color((r,g,b)), color(r,g,b)

pencolor()에서와 같은 입력, 채우기 색상과 펜 색상을 모두 주어진 값으로 설정합니다.

color(colorstring1, colorstring2), color((r1,g1,b1), (r2,g2,b2))

pencolor(colorstring1)과 fillcolor(colorstring2)와 동등하며 다른 입력 형식을 사용하는 경우도 유사합니다.

거북이 모양이 다각형이면, 해당 다각형의 외곽선과 내부가 새로 설정된 색상으로 그려집니다.

>>> turtle.color("red", "green")
>>> turtle.color()
('red', 'green')
>>> color("#285078", "#a0c8f0")
>>> color()
((40.0, 80.0, 120.0), (160.0, 200.0, 240.0))

참조: Screen 메서드 colormode().

채우기

turtle.filling()

채우기 상태(fillstate)를 반환합니다 (채우면 True, 그렇지 않으면 False).

>>> turtle.begin_fill()
>>> if turtle.filling():
...    turtle.pensize(5)
... else:
...    turtle.pensize(3)

turtle.begin_fill()

채울 모양을 그리기 직전에 호출됩니다.

turtle.end_fill()

begin_fill()을 마지막으로 호출한 후 그린 모양을 채웁니다.

스스로 교차하는 다각형이나 여러 도형의 겹치는 영역이 채워지는지는 운영 체제 그래픽, 겹침의 유형 및 겹침의 수에 따라 다릅니다. 예를 들어, 위의 거북이 별은 모두 노란색이거나 일부 흰색 영역이 있을 수 있습니다.

>>> turtle.color("black", "red")
>>> turtle.begin_fill()
>>> turtle.circle(80)
>>> turtle.end_fill()

더 많은 그리기 제어

turtle.reset()

화면에서 거북이의 그림을 삭제하고, 거북이를 다시 중심으로 옮기고, 변수를 기본값으로 설정합니다.

>>> turtle.goto(0,-22)
>>> turtle.left(100)
>>> turtle.position()
(0.00,-22.00)
>>> turtle.heading()
100.0
>>> turtle.reset()
>>> turtle.position()
(0.00,0.00)
>>> turtle.heading()
0.0

turtle.clear()

화면에서 거북이 그림을 삭제합니다. 거북이를 움직이지 않습니다. 다른 거북이의 그림뿐만 아니라 거북이의 상태와 위치는 영향을 받지 않습니다.

turtle.write(arg, move=False, align='left', font=('Arial', 8, 'normal'))

매개변수:

arg – TurtleScreen에 기록될 객체

move – True/False

align – “left”, “center” 또는 “right” 문자열 중 하나

font – 3-튜플 (fontname, fontsize, fonttype)

align(“left”, “center” 또는 “right”)에 따라 현재 거북이 위치에서 주어진 글꼴(font)로 텍스트 - arg의 문자열 표현 - 를 기록합니다. move가 참이면, 펜이 텍스트의 오른쪽 아래 모서리로 이동합니다. 기본적으로, move는 False입니다.

>>> turtle.write("Home = ", True, align="center")
>>> turtle.write((0,0), True)

거북이 상태

가시성

turtle.hideturtle()

turtle.ht()

거북이를 보이지 않게 합니다. 거북이를 숨기면 그리기 속도가 눈에 띄게 빨라지므로, 복잡한 그리기를 하는 동안 이렇게 하는 것이 좋습니다.

>>> turtle.hideturtle()

turtle.showturtle()

turtle.st()

거북이가 보이게 합니다.

>>> turtle.showturtle()

turtle.isvisible()

거북이가 보이면 True를, 숨겨져 있으면 False를 반환합니다.

>>> turtle.hideturtle()
>>> turtle.isvisible()
False
>>> turtle.showturtle()
>>> turtle.isvisible()
True

외관

turtle.shape(name=None)

매개변수:

name – 유효한 모양 이름(shapename)인 문자열

주어진 name의 모양으로 거북이 모양을 설정하거나, 이름이 없으면 현재 모양의 이름을 반환합니다. name의 모양은 TurtleScreen의 모양 딕셔너리에 있어야 합니다. 처음에는 다음과 같은 다각형 모양이 있습니다: “arrow”, “turtle”, “circle”, “square”, “triangle”, “classic”. 모양을 다루는 방법에 대한 자세한 내용은 Screen 메서드 register_shape()을 참조하십시오.

>>> turtle.shape()
'classic'
>>> turtle.shape("turtle")
>>> turtle.shape()
'turtle'

turtle.resizemode(rmode=None)

매개변수:

rmode – 문자열 “auto”, “user”, “noresize” 중 하나

크기 조정 모드(resizemode)를 다음 값 중 하나로 설정합니다: “auto”, “user”, “noresize”. rmode가 제공되지 않으면, 현재 크기 조정 모드를 반환합니다. 각 크기 조정 모드는 다음과 같은 효과가 있습니다:

“auto”: 펜 크기(pensize)의 값에 맞춰 거북이의 외관을 조정합니다.

“user”: shapesize()로 설정된 stretchfactor와 outlinewidth (outline) 값에 따라 거북이의 외관을 조정합니다.

“noresize”: 거북이의 외관 조정이 일어나지 않습니다.

shapesize()에 인자를 사용하면 resizemode("user") 를 호출합니다.

>>> turtle.resizemode()
'noresize'
>>> turtle.resizemode("auto")
>>> turtle.resizemode()
'auto'

turtle.shapesize(stretch_wid=None, stretch_len=None, outline=None)

turtle.turtlesize(stretch_wid=None, stretch_len=None, outline=None)

매개변수:

stretch_wid – 양수

stretch_len – 양수

outline – 양수

Return or set the pen’s attributes x/y-stretchfactors and/or outline. Set resizemode to “user”. If and only if resizemode is set to “user”, the turtle will be displayed stretched according to its stretchfactors: stretch_wid is stretchfactor perpendicular to its orientation, stretch_len is stretchfactor in direction of its orientation, outline determines the width of the shape’s outline.

>>> turtle.shapesize()
(1.0, 1.0, 1)
>>> turtle.resizemode("user")
>>> turtle.shapesize(5, 5, 12)
>>> turtle.shapesize()
(5, 5, 12)
>>> turtle.shapesize(outline=8)
>>> turtle.shapesize()
(5, 5, 8)

turtle.shearfactor(shear=None)

매개변수:

shear – 숫자 (선택 사항)

기울기 계수(shearfactor)를 설정하거나 반환합니다. 주어진 기울기 계수 shear(기울기 각의 탄젠트입니다)에 따라 거북이 모양을 기울입니다. 거북이의 방향(이동 방향)을 변경하지 않습니다. shear가 제공되지 않으면: 현재 기울기 계수(shearfactor)를, 즉 기울기 각도의 탄젠트를 반환합니다. 기울기 각도는 거북이의 방향에 평행한 직선이 기울어진 각도입니다.

>>> turtle.shape("circle")
>>> turtle.shapesize(5,2)
>>> turtle.shearfactor(0.5)
>>> turtle.shearfactor()
0.5

turtle.tilt(angle)

매개변수:

angle – 숫자

현재 틸트 각도(tilt-angle)에서 거북이 모양을 angle만큼 회전합니다. 그러나 거북이의 방향(이동 방향)을 변경하지 않습니다.

>>> turtle.reset()
>>> turtle.shape("circle")
>>> turtle.shapesize(5,2)
>>> turtle.tilt(30)
>>> turtle.fd(50)
>>> turtle.tilt(30)
>>> turtle.fd(50)

turtle.tiltangle(angle=None)

매개변수:

angle – 숫자 (선택 사항)

현재 틸트 각도(tilt-angle)를 설정하거나 반환합니다. angle이 주어지면, 현재 틸트 각도(tilt-angle)와 관계없이 거북이 모양을 angle이 지정하는 방향을 가리키도록 회전합니다. 거북이의 방향(이동 방향)을 변경하지 않습니다. angle이 주어지지 않으면: 현재 틸트 각도, 즉 거북이 모양의 방향과 거북이 방향(이동 방향) 사이의 각도를 반환합니다.

>>> turtle.reset()
>>> turtle.shape("circle")
>>> turtle.shapesize(5,2)
>>> turtle.tilt(45)
>>> turtle.tiltangle()
45.0

turtle.shapetransform(t11=None, t12=None, t21=None, t22=None)

매개변수:

t11 – 숫자 (선택 사항)

t12 – 숫자 (선택 사항)

t21 – 숫자 (선택 사항)

t12 – 숫자 (선택 사항)

거북이 모양의 현재 변환 행렬을 설정하거나 반환합니다.

행렬 요소가 아무것도 제공되지 않으면, 변환 행렬을 4개 요소의 튜플로 반환합니다. 그렇지 않으면, 주어진 요소를 설정하고 첫 번째 행 t11, t12와 두 번째 행 t21, t22로 구성된 행렬에 따라 거북이 모양을 변환합니다. 행렬식(determinant) t11 * t22 - t12 * t21은 0이 아니어야 합니다, 그렇지 않으면 에러가 발생합니다. 주어진 행렬에 따라 신축 계수(stretchfactor), 기울기 계수(shearfactor) 및 틸트 각도(tiltangle)를 수정합니다.

>>> turtle = Turtle()
>>> turtle.shape("square")
>>> turtle.shapesize(4,2)
>>> turtle.shearfactor(-0.5)
>>> turtle.shapetransform()
(4.0, -1.0, -0.0, 2.0)

turtle.get_shapepoly()

현재 모양 다각형을 좌표 쌍의 튜플로 반환합니다. 이것은 새로운 모양이나 복합 모양의 구성 요소를 정의하는 데 사용할 수 있습니다.

>>> turtle.shape("square")
>>> turtle.shapetransform(4, -1, 0, 2)
>>> turtle.get_shapepoly()
((50, -20), (30, 20), (-50, 20), (-30, -20))

이벤트 사용하기

turtle.onclick(fun, btn=1, add=None)

매개변수:

fun – 캔버스에서 클릭한 점의 좌표로 호출되는 두 개의 인자가 있는 함수

btn – 마우스 버튼 수, 기본값은 1 (마우스 왼쪽 버튼)

add – True 또는 False – True이면, 새 연결이 추가되고, 그렇지 않으면 이전 연결을 대체합니다

이 거북이의 마우스 클릭 이벤트에 fun을 연결합니다. fun이 None이면 기존 연결이 제거됩니다. 익명의 거북이, 즉 절차적 방법의 예:

>>> def turn(x, y):
...     left(180)
...
>>> onclick(turn)  # Now clicking into the turtle will turn it.
>>> onclick(None)  # event-binding will be removed

turtle.onrelease(fun, btn=1, add=None)

매개변수:

fun – 캔버스에서 클릭한 점의 좌표로 호출되는 두 개의 인자가 있는 함수

btn – 마우스 버튼 수, 기본값은 1 (마우스 왼쪽 버튼)

add – True 또는 False – True이면, 새 연결이 추가되고, 그렇지 않으면 이전 연결을 대체합니다

이 거북이의 마우스 버튼 해제 이벤트에 fun을 연결합니다. fun이 None이면 기존 연결이 제거됩니다.

>>> class MyTurtle(Turtle):
...     def glow(self,x,y):
...         self.fillcolor("red")
...     def unglow(self,x,y):
...         self.fillcolor("")
...
>>> turtle = MyTurtle()
>>> turtle.onclick(turtle.glow)     # clicking on turtle turns fillcolor red,
>>> turtle.onrelease(turtle.unglow) # releasing turns it to transparent.

turtle.ondrag(fun, btn=1, add=None)

매개변수:

fun – 캔버스에서 클릭한 점의 좌표로 호출되는 두 개의 인자가 있는 함수

btn – 마우스 버튼 수, 기본값은 1 (마우스 왼쪽 버튼)

add – True 또는 False – True이면, 새 연결이 추가되고, 그렇지 않으면 이전 연결을 대체합니다

이 거북이의 마우스 이동 이벤트에 fun을 연결합니다. fun이 None이면 기존 연결이 제거됩니다.

참고: 거북이의 모든 마우스 이동 이벤트에 앞서 해당 거북이의 마우스 클릭 이벤트가 선행합니다.

>>> turtle.ondrag(turtle.goto)

그 후, 거북이를 클릭하고 드래그하면 화면을 가로질러 거북이가 움직여 손 그림을 생성합니다 (펜이 내려가 있다면).

특수 Turtle 메서드

turtle.begin_poly()

다각형의 꼭짓점 기록을 시작합니다. 현재 거북이 위치가 다각형의 첫 번째 꼭짓점입니다.

turtle.end_poly()

다각형의 꼭짓점 기록을 중지합니다. 현재 거북이 위치가 다각형의 마지막 꼭짓점입니다. 첫 번째 꼭짓점과 연결됩니다.

turtle.get_poly()

마지막으로 기록된 다각형을 반환합니다.

>>> turtle.home()
>>> turtle.begin_poly()
>>> turtle.fd(100)
>>> turtle.left(20)
>>> turtle.fd(30)
>>> turtle.left(60)
>>> turtle.fd(50)
>>> turtle.end_poly()
>>> p = turtle.get_poly()
>>> register_shape("myFavouriteShape", p)

turtle.clone()

같은 위치, 방향 및 거북이 속성을 가진 거북이 복제본을 만들고 반환합니다.

>>> mick = Turtle()
>>> joe = mick.clone()

turtle.getturtle()

turtle.getpen()

거북이 객체 자체를 반환합니다. 합리적인 용도로만 사용하십시오: “익명 거북이”를 반환하는 함수로:

>>> pet = getturtle()
>>> pet.fd(50)
>>> pet
<turtle.Turtle object at 0x...>

turtle.getscreen()

거북이가 그리는 TurtleScreen 객체를 반환합니다. 그런 다음 해당 객체에 대해 TurtleScreen 메서드를 호출할 수 있습니다.

>>> ts = turtle.getscreen()
>>> ts
<turtle._Screen object at 0x...>
>>> ts.bgcolor("pink")

turtle.setundobuffer(size)

매개변수:

size – 정수나 None

언두버퍼(undobuffer)를 설정하거나 비활성화합니다. size가 정수이면, 지정된 크기의 빈 언두버퍼가 설치됩니다. size는 undo() 메서드/함수로 취소할 수 있는 최대 거북이 액션 수를 제공합니다. size가 None이면, 언두버퍼가 비활성화됩니다.

>>> turtle.setundobuffer(42)

turtle.undobufferentries()

언두버퍼에 있는 항목 수를 반환합니다.

>>> while undobufferentries():
...     undo()

복합 모양

다른 색상의 여러 다각형으로 구성된 복합 거북이 모양을 사용하려면, 아래 설명된 대로 도우미 클래스 Shape을 명시적으로 사용해야 합니다:

“compound” 유형의 빈 Shape 객체를 만듭니다.

Add as many components to this object as desired, using the addcomponent() method.

예를 들면:

>>> s = Shape("compound")
>>> poly1 = ((0,0),(10,-5),(0,10),(-10,-5))
>>> s.addcomponent(poly1, "red", "blue")
>>> poly2 = ((0,0),(10,-5),(-10,-5))
>>> s.addcomponent(poly2, "blue", "red")

이제 Shape을 Screen의 모양 리스트(shapelist)에 추가하고 사용합니다:

>>> register_shape("myshape", s)
>>> shape("myshape")

참고

Shape 클래스는 register_shape() 메서드에 의해 내부적으로 다른 방식으로 사용됩니다. 응용 프로그램 프로그래머는 위와 같이 복합 모양을 사용할 때 만 Shape 클래스를 다뤄야 합니다!

TurtleScreen/Screen 메서드와 해당 함수

이 섹션의 대부분의 예제는 screen이라는 TurtleScreen 인스턴스를 참조합니다.

창 제어

turtle.bgcolor(*args)

매개변수:

args – 색상 문자열이나 0..colormode 범위의 3개의 숫자 또는 이러한 숫자의 3-튜플

TurtleScreen의 배경색을 설정하거나 반환합니다.

>>> screen.bgcolor("orange")
>>> screen.bgcolor()
'orange'
>>> screen.bgcolor("#800080")
>>> screen.bgcolor()
(128.0, 0.0, 128.0)

turtle.bgpic(picname=None)

매개변수:

picname – 문자열, gif 파일의 이름 또는 "nopic", 또는 None

배경 이미지를 설정하거나 현재 배경 이미지(backgroundimage)의 이름을 반환합니다. picname이 파일명이면, 해당 이미지를 배경으로 설정합니다. picname이 "nopic"이면, 배경 이미지가 있다면 삭제합니다. picname이 None이면, 현재 배경 이미지(backgroundimage)의 파일명을 반환합니다.

>>> screen.bgpic()
'nopic'
>>> screen.bgpic("landscape.gif")
>>> screen.bgpic()
"landscape.gif"

turtle.clear()

참고

이 TurtleScreen 메서드는 clearscreen이라는 이름으로만 전역 함수로 사용할 수 있습니다. 전역 함수 clear는 Turtle 메서드 clear에서 파생된 다른 것입니다.

turtle.clearscreen()

TurtleScreen에서 모든 그림과 모든 거북이를 삭제합니다. 이제 비어있는 TurtleScreen을 초기 상태로 재설정합니다: 흰색 배경, 배경 이미지 없음, 이벤트 연결과 추적 없음.

turtle.reset()

참고

이 TurtleScreen 메서드는 resetscreen이라는 이름으로만 전역 함수로 사용할 수 있습니다. 전역 함수 reset은 Turtle 메서드 reset에서 파생된 또 다른 함수입니다.

turtle.resetscreen()

Screen의 모든 거북이를 초기 상태로 재설정합니다.

turtle.screensize(canvwidth=None, canvheight=None, bg=None)

매개변수:

canvwidth – 양의 정수, 픽셀 단위의 새 캔버스 너비

canvheight – 양의 정수, 픽셀 단위의 새 캔버스 높이

bg – 색상 문자열(colorstring)이나 색상 튜플, 새 배경색

인자가 제공되지 않으면, 현재 (canvaswidth, canvasheight)를 반환합니다. 그렇지 않으면 거북이가 그리는 캔버스의 크기를 조정합니다. 그리는 창을 변경하지 마십시오. 캔버스의 숨겨진 부분을 보려면, 스크롤 막대를 사용하십시오. 이 메서드를 사용하면, 이전에 캔버스 외부에 있던 그림의 부분을 볼 수 있습니다.

>>> screen.screensize()
(400, 300)
>>> screen.screensize(2000,1500)
>>> screen.screensize()
(2000, 1500)

예를 들어 잘못 탈출한 거북이를 찾기 위해 ;-)

turtle.setworldcoordinates(llx, lly, urx, ury)

매개변수:

llx – 숫자, 캔버스의 왼쪽 아래 모서리의 x-좌표

lly – 숫자, 캔버스의 왼쪽 아래 모서리의 y-좌표

urx – 숫자, 캔버스의 오른쪽 상단 모서리의 x-좌표

ury – 숫자, 캔버스의 오른쪽 상단 모서리의 y-좌표

사용자 정의 좌표계를 설정하고 필요하면 “world” 모드로 전환합니다. 이것은 screen.reset()을 수행합니다. “world” 모드가 이미 활성화되었으면, 모든 그림은 새 좌표에 따라 다시 그려집니다.

주의: 사용자 정의 좌표계에서 각도가 왜곡되어 나타날 수 있습니다.

>>> screen.reset()
>>> screen.setworldcoordinates(-50,-7.5,50,7.5)
>>> for _ in range(72):
...     left(10)
...
>>> for _ in range(8):
...     left(45); fd(2)   # a regular octagon

애니메이션 제어

turtle.delay(delay=None)

매개변수:

delay – 양의 정수

그리기 지연(delay)을 밀리초 단위로 설정하거나 반환합니다. (이는 대략 두 개의 연속 캔버스 갱신 사이의 시간 간격입니다.) 그리기 지연이 길수록, 애니메이션이 느려집니다.

선택적 인자:

>>> screen.delay()
10
>>> screen.delay(5)
>>> screen.delay()
5

turtle.tracer(n=None, delay=None)

매개변수:

n – 음이 아닌 정수

delay – 음이 아닌 정수

거북이 애니메이션을 켜거나 끄고 그림 갱신 지연을 설정합니다. n이 제공되면, n 번째 정기 화면 갱신만 실제로 수행됩니다. (복잡한 그래픽의 그리기를 가속하는 데 사용할 수 있습니다.) 인자 없이 호출되면, 현재 저장된 n 값을 반환합니다. 두 번째 인자는 지연(delay) 값을 설정합니다 (delay()를 참조하십시오).

>>> screen.tracer(8, 25)
>>> dist = 2
>>> for i in range(200):
...     fd(dist)
...     rt(90)
...     dist += 2

turtle.update()

TurtleScreen 갱신을 수행합니다. tracer가 꺼져있을 때 사용됩니다.

RawTurtle/Turtle 메서드 speed()도 참조하십시오.

화면 이벤트 사용하기

turtle.listen(xdummy=None, ydummy=None)

(키 이벤트를 수집하기 위해) TurtleScreen에 포커스를 설정합니다. listen()을 onclick 메서드에 전달할 수 있도록 더미 인자가 제공됩니다.

turtle.onkey(fun, key)

turtle.onkeyrelease(fun, key)

매개변수:

fun – 인자가 없는 함수나 None

key – 문자열: 키 (예를 들어 “a”) 또는 키-기호 (예를 들어 “space”)

key의 키-릴리스 이벤트에 fun을 연결합니다. fun이 None이면, 이벤트 연결이 제거됩니다. 비고: 키 이벤트를 등록하려면, TurtleScreen에 포커스가 있어야 합니다. (메서드 listen()을 참조하십시오.)

>>> def f():
...     fd(50)
...     lt(60)
...
>>> screen.onkey(f, "Up")
>>> screen.listen()

turtle.onkeypress(fun, key=None)

매개변수:

fun – 인자가 없는 함수나 None

key – 문자열: 키 (예를 들어 “a”) 또는 키-기호 (예를 들어 “space”)

key가 제공되면 key의 키-누르기 이벤트에 또는 key를 제공하지 않으면 임의의 키 누르기 이벤트에 fun을 연결합니다. 비고: 키 이벤트를 등록하려면, TurtleScreen에 포커스가 있어야 합니다. (메서드 listen()을 참조하십시오.)

>>> def f():
...     fd(50)
...
>>> screen.onkey(f, "Up")
>>> screen.listen()

turtle.onclick(fun, btn=1, add=None)

turtle.onscreenclick(fun, btn=1, add=None)

매개변수:

fun – 캔버스에서 클릭한 점의 좌표로 호출되는 두 개의 인자가 있는 함수

btn – 마우스 버튼 수, 기본값은 1 (마우스 왼쪽 버튼)

add – True 또는 False – True이면, 새 연결이 추가되고, 그렇지 않으면 이전 연결을 대체합니다

이 화면의 마우스-클릭 이벤트에 fun을 연결합니다. fun이 None이면, 기존 연결이 제거됩니다.

이름이 screen인 TurtleScreen 인스턴스와 이름이 turtle인 거북이 인스턴스의 예:

>>> screen.onclick(turtle.goto) # Subsequently clicking into the TurtleScreen will
>>>                             # make the turtle move to the clicked point.
>>> screen.onclick(None)        # remove event binding again

참고

이 TurtleScreen 메서드는 onscreenclick이라는 이름으로만 전역 함수로 사용할 수 있습니다. 전역 함수 onclick은 Turtle 메서드 onclick에서 파생된 또 다른 함수입니다.

turtle.ontimer(fun, t=0)

매개변수:

fun – 인자가 없는 함수

t – 숫자 >= 0

t 밀리초 후에 fun을 호출하는 타이머를 설치합니다.

>>> running = True
>>> def f():
...     if running:
...         fd(50)
...         lt(60)
...         screen.ontimer(f, 250)
>>> f()   ### makes the turtle march around
>>> running = False

turtle.mainloop()

turtle.done()

이벤트 루프를 시작합니다 - Tkinter의 mainloop 함수를 호출합니다. 터틀 그래픽 프로그램의 마지막 문장이어야 합니다. 터틀 그래픽을 대화식으로 사용하기 위해 -n 모드(서브 프로세스 없음)로 IDLE에서 스크립트를 실행할 때는 사용되지 않아야 합니다.

>>> screen.mainloop()

입력 메서드

turtle.textinput(title, prompt)

매개변수:

title – 문자열

prompt – 문자열

문자열 입력을 위한 대화 상자 창을 띄웁니다. 매개변수 title은 대화 상자 창의 제목이고, prompt는 주로 어떤 정보를 입력해야 하는지 설명하는 텍스트입니다. 문자열 입력을 반환합니다. 대화 상자가 취소되면, None을 반환합니다.

>>> screen.textinput("NIM", "Name of first player:")

turtle.numinput(title, prompt, default=None, minval=None, maxval=None)

매개변수:

title – 문자열

prompt – 문자열

default – 숫자 (선택 사항)

minval – 숫자 (선택 사항)

maxval – 숫자 (선택 사항)

Pop up a dialog window for input of a number. title is the title of the dialog window, prompt is a text mostly describing what numerical information to input. default: default value, minval: minimum value for input, maxval: maximum value for input. The number input must be in the range minval .. maxval if these are given. If not, a hint is issued and the dialog remains open for correction. Return the number input. If the dialog is canceled, return None.

>>> screen.numinput("Poker", "Your stakes:", 1000, minval=10, maxval=10000)

설정과 특수 메서드

turtle.mode(mode=None)

매개변수:

mode – 문자열 “standard”, “logo” 또는 “world” 중 하나

거북이 모드(“standard”, “logo” 또는 “world”)를 설정하고 재설정을 수행합니다. mode가 제공되지 않으면, 현재 모드가 반환됩니다.

“standard” 모드는 이전 turtle과 호환됩니다. “logo” 모드는 대부분의 로고 터틀 그래픽과 호환됩니다. “world” 모드는 사용자 정의 “세계 좌표”를 사용합니다. 주의: 이 모드에서는 x/y 단위 비율이 1이 아니면 각도가 왜곡되어 나타납니다.

모드

초기 거북이 방향

양의 각도

“standard”

오른쪽 (동)

시계 반대 방향

“logo”

위쪽 (북)

시계 방향

>>> mode("logo")   # resets turtle heading to north
>>> mode()
'logo'

turtle.colormode(cmode=None)

매개변수:

cmode – 값 1.0이나 255중 하나

Return the colormode or set it to 1.0 or 255. Subsequently r, g, b values of color triples have to be in the range 0..*cmode*.

>>> screen.colormode(1)
>>> turtle.pencolor(240, 160, 80)
Traceback (most recent call last):
     ...
TurtleGraphicsError: bad color sequence: (240, 160, 80)
>>> screen.colormode()
1.0
>>> screen.colormode(255)
>>> screen.colormode()
255
>>> turtle.pencolor(240,160,80)

turtle.getcanvas()

이 TurtleScreen의 캔버스를 반환합니다. Tkinter Canvas로 작업하는 법을 알고 있는 내부자에게 유용합니다.

>>> cv = screen.getcanvas()
>>> cv
<turtle.ScrolledCanvas object ...>

turtle.getshapes()

현재 사용 가능한 모든 거북이 모양의 이름 리스트를 반환합니다.

>>> screen.getshapes()
['arrow', 'blank', 'circle', ..., 'turtle']

turtle.register_shape(name, shape=None)

turtle.addshape(name, shape=None)

이 함수를 호출하는 방법에는 세 가지가 있습니다:

name은 gif 파일의 이름이고 shape은 None입니다: 해당 이미지 모양을 설치합니다.

>>> screen.register_shape("turtle.gif")

참고

거북이를 회전할 때 이미지 모양은 회전하지 않아서, 거북이 방향을 표시하지 않습니다!

name은 임의의 문자열이고 shape은 좌표 쌍의 튜플입니다: 해당 다각형 모양을 설치합니다.

>>> screen.register_shape("triangle", ((5,-3), (0,5), (-5,-3)))

name is an arbitrary string and shape is a (compound) Shape object: Install the corresponding compound shape.

TurtleScreen의 모양 리스트(shapelist)에 거북이 모양을 추가합니다. shape(shapename) 명령을 실행하면 이처럼 등록된 모양만 사용할 수 있습니다.

turtle.turtles()

화면에 있는 거북이의 리스트를 반환합니다.

>>> for turtle in screen.turtles():
...     turtle.color("red")

turtle.window_height()

거북이 창의 높이를 반환합니다.

>>> screen.window_height()
480

turtle.window_width()

거북이 창의 너비를 반환합니다.

>>> screen.window_width()
640

TurtleScreen에서 상속되지 않은, Screen만의 메서드

turtle.bye()

터틀 그래픽 창을 닫습니다.

turtle.exitonclick()

bye() 메서드를 Screen에서의 마우스 클릭에 연결합니다.

구성 딕셔너리의 “using_IDLE” 값이 False(기본값)면, 에인 루프에 진입하기도 합니다. 비고: -n 스위치로 IDLE(서브 프로세스 없음)을 사용하면, 이 값은 turtle.cfg에서 True로 설정되어야 합니다. 이 경우 IDLE의 자체 메인 루프는 클라이언트 스크립트에서도 활성화됩니다.

turtle.save(filename, overwrite=False)

Save the current turtle drawing (and turtles) as a PostScript file.

매개변수:

filename – the path of the saved PostScript file

overwrite – if False and there already exists a file with the given filename, then the function will raise a FileExistsError. If it is True, the file will be overwritten.

>>> screen.save("my_drawing.ps")
>>> screen.save("my_drawing.ps", overwrite=True)

Added in version 3.14.

turtle.setup(width=_CFG['width'], height=_CFG['height'], startx=_CFG['leftright'], starty=_CFG['topbottom'])

메인 창의 크기와 위치를 설정합니다. 인자의 기본값은 구성 딕셔너리에 저장되며 turtle.cfg 파일을 통해 변경할 수 있습니다.

매개변수:

width – 정수면 픽셀 단위의 크기, 실수면 화면의 비율; 기본값은 화면의 50%입니다

height – 정수면 픽셀 단위의 높이, 실수면 화면의 비율; 기본값은 화면의 75%입니다

startx – 양수이면 화면의 왼쪽 가장자리에서부터의 픽셀 단위의 시작 위치, 음수이면 오른쪽 가장자리에서부터, None이면 창을 가로로 가운데 정렬합니다

starty – 양수이면 화면 위쪽 가장자리에서부터의 픽셀 단위의 시작 위치, 음수이면 아래쪽 가장자리에서부터, None이면 창을 세로로 가운데 정렬합니다

>>> screen.setup (width=200, height=200, startx=0, starty=0)
>>>              # sets window to 200x200 pixels, in upper left of screen
>>> screen.setup(width=.75, height=0.5, startx=None, starty=None)
>>>              # sets window to 75% of screen by 50% of screen and centers

turtle.title(titlestring)

매개변수:

titlestring – 터틀 그래픽 창의 제목 표시 줄에 표시되는 문자열

거북이 창의 제목을 titlestring으로 설정합니다.

>>> screen.title("Welcome to the turtle zoo!")

공개 클래스

class turtle.RawTurtle(canvas)

class turtle.RawPen(canvas)

매개변수:

canvas – a tkinter.Canvas, a ScrolledCanvas or a TurtleScreen

거북이를 만듭니다. 거북이는 위에서 “Turtle/RawTurtle의 메서드”라고 언급한 모든 메서드를 갖습니다.

class turtle.Turtle

RawTurtle의 서브 클래스. 인터페이스는 같지만 처음 필요할 때 자동으로 생성된 기본 Screen 객체에 그립니다.

class turtle.TurtleScreen(cv)

매개변수:

cv – a tkinter.Canvas

Provides screen oriented methods like bgcolor() etc. that are described above.

class turtle.Screen

TurtleScreen의 서브 클래스. 4개의 메서드가 추가되었습니다.

class turtle.ScrolledCanvas(master)

매개변수:

master – ScrolledCanvas, 즉 스크롤 막대가 추가된 Tkinter-Canvas를 담을 어떤 Tkinter 위젯

클래스 Screen에서 사용되며, 거북 놀이터로 ScrolledCanvas를 자동으로 제공합니다.

class turtle.Shape(type_, data)

매개변수:

type_ – 문자열 “polygon”, “image”, “compound” 중 하나

모양을 모델링하는 데이터 구조. 쌍 (type_, data)는 다음 명세를 따라야 합니다:

type_

data

“polygon”

다각형 튜플, 즉 좌표 쌍의 튜플

“image”

이미지 (이 형식은 내부적으로만 사용됩니다!)

“compound”

None (복합 모양을 addcomponent() 메서드를 사용하여 구성해야 합니다)

addcomponent(poly, fill, outline=None)

매개변수:

poly – 다각형, 즉 숫자 쌍의 튜플

fill – poly가 채워질 색상

outline – poly 외곽선의 색상 (제공되면)

예:

>>> poly = ((0,0),(10,-5),(0,10),(-10,-5))
>>> s = Shape("compound")
>>> s.addcomponent(poly, "red", "blue")
>>> # ... add more components and then use register_shape()

복합 모양을 참조하십시오.

class turtle.Vec2D(x, y)

2차원 벡터 클래스. 터틀 그래픽을 구현하기 위한 도우미 클래스로 사용됩니다. 터틀 그래픽 프로그램에도 유용할 수 있습니다. 튜플에서 파생되기 때문에, 벡터는 튜플입니다!

다음을 제공합니다 (a, b는 벡터, k는 번호):

a + b 벡터 덧셈

a - b 벡터 뺄셈

a * b 내적(inner product)

k * a와 a * k 스칼라를 사용한 곱셈

abs(a) a의 절댓값

a.rotate(angle) 회전

Explanation

A turtle object draws on a screen object, and there a number of key classes in the turtle object-oriented interface that can be used to create them and relate them to each other.

A Turtle instance will automatically create a Screen instance if one is not already present.

Turtle is a subclass of RawTurtle, which doesn’t automatically create a drawing surface - a canvas will need to be provided or created for it. The canvas can be a tkinter.Canvas, ScrolledCanvas or TurtleScreen.

TurtleScreen is the basic drawing surface for a turtle. Screen is a subclass of TurtleScreen, and includes some additional methods for managing its appearance (including size and title) and behaviour. TurtleScreen’s constructor needs a tkinter.Canvas or a ScrolledCanvas as an argument.

The functional interface for turtle graphics uses the various methods of Turtle and TurtleScreen/Screen. Behind the scenes, a screen object is automatically created whenever a function derived from a Screen method is called. Similarly, a turtle object is automatically created whenever any of the functions derived from a Turtle method is called.

To use multiple turtles on a screen, the object-oriented interface must be used.

도움말과 구성

도움말 사용법

Screen과 Turtle 클래스의 공개 메서드는 독스트링을 통해 광범위하게 설명됩니다. 파이썬 도움말 기능을 통해 온라인 도움말로 사용할 수 있습니다:

IDLE을 사용할 때, 툴팁은 입력된 함수/메서드 호출의 서명과 독스트링의 첫 줄을 보여줍니다.

메서드나 함수에 대해 help()를 호출하면 독스트링을 표시합니다:

>>> help(Screen.bgcolor)
Help on method bgcolor in module turtle:

bgcolor(self, *args) unbound turtle.Screen method
    Set or return backgroundcolor of the TurtleScreen.

    Arguments (if given): a color string or three numbers
    in the range 0..colormode or a 3-tuple of such numbers.

    >>> screen.bgcolor("orange")
    >>> screen.bgcolor()
    "orange"
    >>> screen.bgcolor(0.5,0,0.5)
    >>> screen.bgcolor()
    "#800080"

>>> help(Turtle.penup)
Help on method penup in module turtle:

penup(self) unbound turtle.Turtle method
    Pull the pen up -- no drawing when moving.

    Aliases: penup | pu | up

    No argument

    >>> turtle.penup()

메서드에서 파생된 함수의 독스트링은 다음과 같이 수정된 형식을 갖습니다:

>>> help(bgcolor)
Help on function bgcolor in module turtle:

bgcolor(*args)
    Set or return backgroundcolor of the TurtleScreen.

    Arguments (if given): a color string or three numbers
    in the range 0..colormode or a 3-tuple of such numbers.

    Example::

      >>> bgcolor("orange")
      >>> bgcolor()
      "orange"
      >>> bgcolor(0.5,0,0.5)
      >>> bgcolor()
      "#800080"

>>> help(penup)
Help on function penup in module turtle:

penup()
    Pull the pen up -- no drawing when moving.

    Aliases: penup | pu | up

    No argument

    Example:
    >>> penup()

이러한 수정된 독스트링은 임포트 시점에 메서드에서 파생된 함수 정의와 함께 자동으로 만들어집니다.

독스트링을 다른 언어로 번역

키가 메서드 이름이고 값이 Screen과 Turtle 클래스의 공개 메서드의 독스트링인 딕셔너리를 만드는 유틸리티가 있습니다.

turtle.write_docstringdict(filename='turtle_docstringdict')

매개변수:

filename – 파일명으로 사용되는 문자열

주어진 파일명의 파이썬 스크립트에 독스트링-딕셔너리를 만들고 씁니다. 이 함수는 명시적으로 호출해야 합니다 (터틀 그래픽 클래스에서는 사용되지 않습니다). 독스트링 딕셔너리는 파이썬 스크립트 filename.py에 기록됩니다. 독스트링을 다른 언어로 번역하기 위한 템플릿으로 사용하려는 목적입니다.

여러분(또는 여러분의 학생)이 모국어로 된 온라인 도움말과 함께 turtle을 사용하려면, 독스트링을 번역하고 결과 파일을 예를 들어 turtle_docstringdict_german.py와 같은 파일로 저장해야 합니다.

여러분의 turtle.cfg 파일에 적절한 항목이 있으면 임포트 시점에 이 딕셔너리를 읽고 원래 영어 독스트링을 대체합니다.

이 글을 쓰는 시점에는 독일어와 이탈리아어로 된 독스트링 딕셔너리가 있습니다. (glingl@aon.at 에 요청하십시오.)

Screen과 Turtle을 구성하는 방법

내장된 기본 구성은 최상의 호환성을 유지하기 위해 기존 turtle 모듈의 외관과 동작을 모방합니다.

이 모듈의 기능을 더 잘 반영하거나 예를 들어 교실에서 사용하기 위해 필요에 더 잘 맞는 다른 구성을 사용하려면, 임포트 시점에 읽는 구성 파일 turtle.cfg를 준비하고 구성을 그 설정에 따라 수정할 수 있습니다.

The built in configuration would correspond to the following turtle.cfg:

width = 0.5
height = 0.75
leftright = None
topbottom = None
canvwidth = 400
canvheight = 300
mode = standard
colormode = 1.0
delay = 10
undobuffersize = 1000
shape = classic
pencolor = black
fillcolor = black
resizemode = noresize
visible = True
language = english
exampleturtle = turtle
examplescreen = screen
title = Python Turtle Graphics
using_IDLE = False

선택된 항목에 대한 간단한 설명:

The first four lines correspond to the arguments of the Screen.setup method.

Line 5 and 6 correspond to the arguments of the method Screen.screensize.

shape은 내장 도형 중 하나일 수 있습니다, 예를 들어 arrow, turtle 등. 자세한 정보는 help(shape)을 시도해 보십시오.

If you want to use no fill color (i.e. make the turtle transparent), you have to write fillcolor = "" (but all nonempty strings must not have quotes in the cfg file).

거북이의 상태를 반영하려면, resizemode = auto를 사용해야 합니다.

If you set e.g. language = italian the docstringdict turtle_docstringdict_italian.py will be loaded at import time (if present on the import path, e.g. in the same directory as turtle).

exampleturtle과 examplescreen 항목은 독스트링에서 등장하는 이러한 객체들의 이름을 정의합니다. 메서드 독스트링을 함수 독스트링으로 변환하면 이러한 이름이 독스트링에서 삭제됩니다.

using_IDLE: Set this to True if you regularly work with IDLE and its -n switch (“no subprocess”). This will prevent exitonclick() to enter the mainloop.

turtle이 저장된 디렉터리에 turtle.cfg 파일이 있고 현재 작업 디렉터리에도 추가 파일이 있을 수 있습니다. 후자가 첫 번째 설정을 재정의합니다.

Lib/turtledemo 디렉터리는 turtle.cfg 파일을 포함합니다. 예제로 공부하고 데모를 실행할 때 그 효과를 볼 수 있습니다 (바람직하게는 데모 뷰어 내에서는 아닙니다).

turtledemo — 데모 스크립트

turtledemo 패키지에는 데모 스크립트 집합이 포함되어 있습니다. 이 스크립트는 다음과 같이 제공된 데모 뷰어를 사용하여 실행하고 볼 수 있습니다:

python -m turtledemo

또는, 데모 스크립트를 개별적으로 실행할 수 있습니다. 예를 들면,

python -m turtledemo.bytedesign

turtledemo 패키지 디렉터리는 다음과 같은 것들을 포함합니다:

스크립트의 소스 코드를 보고 동시에 실행하는 데 사용할 수 있는 데모 뷰어 __main__.py.

turtle 모듈의 다른 기능을 보여주는 여러 스크립트. 예제는 Examples 메뉴를 통해 액세스할 수 있습니다. 독립형으로 실행할 수도 있습니다.

구성 파일을 작성하고 사용하는 방법의 예인 turtle.cfg 파일.

데모 스크립트는 다음과 같습니다:

이름

설명

기능

bytedesign

복잡한 클래식 터틀 그래픽 패턴

tracer(), delay, update()

chaos

베르홀스트(Verhulst) 동역학의 그래프를 그립니다, 컴퓨터의 계산이 때때로 상식적인 기대에 반하는 결과를 생 할 수 있음을 보여줍니다

세계 좌표

clock

컴퓨터의 시간을 보여주는 아날로그 시계

시곗바늘 거북이, ontimer

colormixer

r, g, b 실험

ondrag()

forest

3개의 너비 우선 나무

무작위화

fractalcurves

힐버트(Hilbert)와 코흐(Koch) 곡선

재귀

lindenmayer

민족 수학 (인도 콜람)

L-System

minimal_hanoi

하노이의 탑

하노이 디스크로 쓰는 직사각형 거북 (모양, 모양 크기)

nim

3개의 막대 더미로 컴퓨터와 고전적인 님 게임을 합니다.

님 막대로 쓰는 거북, 이벤트 구동 (마우스, 키보드)

paint

극도로 단순한 그리기 프로그램

onclick()

peace

기초

거북이: 외관과 애니메이션

penrose

연과 다트가 있는 비주기적 타일링

stamp()

planet_and_moon

중력 시스템 시뮬레이션

복합 모양, Vec2D

rosette

터틀 그래픽에 관한 위키피디아 기사의 패턴

clone(), undo()

round_dance

반대 방향으로 쌍으로 회전하는 춤추는 거북이

복합 모양, 모양 크기 복제, tilt, get_shapepoly, update

sorting_animate

여러 정렬 방법의 시각적 데모

간단한 정렬, 무작위화

tree

(그래픽) 너비 우선 나무 (제너레이터 사용)

clone()

two_canvases

간단한 디자인

두 캔버스의 거북이

yinyang

또 하나의 기초 예제

circle()

즐기세요!

파이썬 2.6 이후의 변화

The methods Turtle.tracer, Turtle.window_width and Turtle.window_height have been eliminated. Methods with these names and functionality are now available only as methods of Screen. The functions derived from these remain available. (In fact already in Python 2.6 these methods were merely duplications of the corresponding TurtleScreen/Screen methods.)

The method Turtle.fill() has been eliminated. The behaviour of begin_fill() and end_fill() have changed slightly: now every filling process must be completed with an end_fill() call.

A method Turtle.filling has been added. It returns a boolean value: True if a filling process is under way, False otherwise. This behaviour corresponds to a fill() call without arguments in Python 2.6.

파이썬 3.0 이후의 변화

The Turtle methods shearfactor(), shapetransform() and get_shapepoly() have been added. Thus the full range of regular linear transforms is now available for transforming turtle shapes. tiltangle() has been enhanced in functionality: it now can be used to get or set the tilt angle.

The Screen method onkeypress() has been added as a complement to onkey(). As the latter binds actions to the key release event, an alias: onkeyrelease() was also added for it.

The method Screen.mainloop has been added, so there is no longer a need to use the standalone mainloop() function when working with Screen and Turtle objects.

Two input methods have been added: Screen.textinput and Screen.numinput. These pop up input dialogs and return strings and numbers respectively.

cmd — Support for line-oriented command interpreters

소스 코드: Lib/cmd.py [https://github.com/python/cpython/tree/main/Lib/cmd.py]

Cmd 클래스는 줄 지향 명령 인터프리터를 작성하기 위한 간단한 프레임워크를 제공합니다. 이것들은 종종 테스트 하네스(test harnesses), 관리 도구 및 나중에 더 복잡한 인터페이스로 포장될 프로토타입에 유용합니다.

class cmd.Cmd(completekey='tab', stdin=None, stdout=None)

Cmd 인스턴스나 서브 클래스 인스턴스는 줄 지향 인터프리터 프레임워크입니다. Cmd 자체를 인스턴스로 만들 이유는 없습니다; 그보다는, Cmd의 메서드를 상속하고 액션 메서드를 캡슐화하기 위해 여러분 스스로 정의한 인터프리터 클래스의 슈퍼 클래스로 유용합니다.

선택적 인자 completekey는 완성 키(completion key)의 readline 이름입니다; 기본값은 Tab입니다. completekey가 None이 아니고 readline을 사용할 수 있으면, 명령 완성이 자동으로 수행됩니다.

The default, 'tab', is treated specially, so that it refers to the Tab key on every readline.backend. Specifically, if readline.backend is editline, Cmd will use '^I' instead of 'tab'. Note that other values are not treated this way, and might only work with a specific backend.

선택적 인자 stdin과 stdout은 Cmd 인스턴스나 서브 클래스 인스턴스가 입출력에 사용할 입력과 출력 파일 객체를 지정합니다. 지정하지 않으면, 기본적으로 sys.stdin과 sys.stdout이 됩니다.

지정된 stdin을 사용하려면, 인스턴스의 use_rawinput 어트리뷰트를 False로 설정해야 합니다, 그렇지 않으면 stdin이 무시됩니다.

버전 3.13에서 변경: completekey='tab' is replaced by '^I' for editline.

Cmd 객체

Cmd 인스턴스에는 다음과 같은 메서드가 있습니다:

Cmd.cmdloop(intro=None)

반복해서 프롬프트를 제시하고, 입력을 받아들이고, 수신된 입력에서 초기 접두사를 구문 분석하고, 줄의 나머지 부분을 인자로 전달해서 액션 메서드를 호출합니다.

선택적 인자는 첫 번째 프롬프트 전에 제시할 배너나 소개 문자열입니다 (이것은 intro 클래스 어트리뷰트를 재정의합니다).

readline 모듈이 로드되면, 입력은 자동으로 bash와 유사한 히스토리 목록 편집을 상속합니다 (예를 들어, Control-P는 직전 명령으로 돌아가고(scroll back), Control-N은 다음 명령으로 이동하고(forward), Control-F는 커서를 비파괴적으로 오른쪽으로 이동하고, Control-B는 커서를 비파괴적으로 왼쪽으로 이동하고, 등등).

입력의 파일 끝(end-of-file)은 문자열 'EOF'로 전달됩니다.

An interpreter instance will recognize a command name foo if and only if it has a method do_foo(). As a special case, a line beginning with the character '?' is dispatched to the method do_help(). As another special case, a line beginning with the character '!' is dispatched to the method do_shell() (if such a method is defined).

This method will return when the postcmd() method returns a true value. The stop argument to postcmd() is the return value from the command’s corresponding do_*() method.

If completion is enabled, completing commands will be done automatically, and completing of commands args is done by calling complete_foo() with arguments text, line, begidx, and endidx. text is the string prefix we are attempting to match: all returned matches must begin with it. line is the current input line with leading whitespace removed, begidx and endidx are the beginning and ending indexes of the prefix text, which could be used to provide different completion depending upon which position the argument is in.

Cmd.do_help(arg)

All subclasses of Cmd inherit a predefined do_help(). This method, called with an argument 'bar', invokes the corresponding method help_bar(), and if that is not present, prints the docstring of do_bar(), if available. With no argument, do_help() lists all available help topics (that is, all commands with corresponding help_*() methods or commands that have docstrings), and also lists any undocumented commands.

Cmd.onecmd(str)

Interpret the argument as though it had been typed in response to the prompt. This may be overridden, but should not normally need to be; see the precmd() and postcmd() methods for useful execution hooks. The return value is a flag indicating whether interpretation of commands by the interpreter should stop. If there is a do_*() method for the command str, the return value of that method is returned, otherwise the return value from the default() method is returned.

Cmd.emptyline()

프롬프트에 응답하여 빈 줄을 입력할 때 호출되는 메서드. 이 메서드를 재정의하지 않으면, 입력된 마지막 비어 있지 않은 명령을 반복합니다.

Cmd.default(line)

명령 접두사가 인식되지 않을 때 입력 줄로 호출되는 메서드. 이 메서드를 재정의하지 않으면, 에러 메시지를 인쇄하고 반환합니다.

Cmd.completedefault(text, line, begidx, endidx)

Method called to complete an input line when no command-specific complete_*() method is available. By default, it returns an empty list.

Cmd.columnize(list, displaywidth=80)

Method called to display a list of strings as a compact set of columns. Each column is only as wide as necessary. Columns are separated by two spaces for readability.

Cmd.precmd(line)

명령 줄 line을 해석하기 직전에, 하지만 입력 프롬프트가 생성되고 제시된 후에 실행되는 훅 메서드. 이 메서드는 Cmd에서는 스텁(stub)입니다; 서브 클래스에 의해 재정의되기 위해 존재합니다. 반환 값은 onecmd() 메서드에 의해 실행될 명령으로 사용됩니다; precmd() 구현은 명령을 다시 쓰거나 단순히 line을 변경하지 않고 반환 할 수 있습니다.

Cmd.postcmd(stop, line)

명령 호출이 완료된 직후에 실행되는 훅 메서드. 이 메서는 Cmd에서는 스텁(stub)입니다; 서브 클래스에 의해 재정의되기 위해 존재합니다. line은 실행된 명령 줄이고, stop은 postcmd()를 호출한 후 실행이 종료될지를 나타내는 플래그입니다; 이것은 onecmd() 메서드의 반환 값입니다. 이 메서드의 반환 값은 stop에 해당하는 내부 플래그의 새 값으로 사용됩니다; 거짓을 반환하면 해석이 계속됩니다.

Cmd.preloop()

cmdloop()가 호출될 때 한 번 실행되는 훅 메서드. 이 메서드는 Cmd에서는 스텁(stub)입니다; 서브 클래스에 의해 재정의되기 위해 존재합니다.

Cmd.postloop()

cmdloop()가 반환하려고 할 때 한 번 실행되는 훅 메서드. 이 메서드는 Cmd에서는 스텁(stub)입니다; 서브 클래스에 의해 재정의되기 위해 존재합니다.

Cmd 서브 클래스의 인스턴스에는 몇 가지 공용 인스턴스 변수가 있습니다:

Cmd.prompt

입력을 요청하는 프롬프트.

Cmd.identchars

명령 접두사에 허용되는 문자들의 문자열.

Cmd.lastcmd

비어 있지 않은 마지막 명령 접두사.

Cmd.cmdqueue

계류 중인 입력 줄의 리스트. cmdqueue 리스트는 새로운 입력이 필요할 때 cmdloop()에서 점검됩니다; 비어 있지 않으면, 프롬프트에서 입력한 것처럼 해당 요소가 순서대로 처리됩니다.

Cmd.intro

소개나 배너로 제시할 문자열. cmdloop() 메서드에 인자를 제공하여 재정의할 수 있습니다.

Cmd.doc_header

도움말 출력에 설명된 명령 섹션이 있을 때 제시할 헤더입니다.

Cmd.misc_header

The header to issue if the help output has a section for miscellaneous help topics (that is, there are help_*() methods without corresponding do_*() methods).

Cmd.undoc_header

The header to issue if the help output has a section for undocumented commands (that is, there are do_*() methods without corresponding help_*() methods).

Cmd.ruler

도움말 메시지 헤더 아래에 구분선을 그리는 데 사용되는 문자입니다. 비어 있으면, 눈금자 선이 그려지지 않습니다. 기본값은 '='입니다.

Cmd.use_rawinput

A flag, defaulting to true. If true, cmdloop() uses input() to display a prompt and read the next command; if false, sys.stdout.write() and sys.stdin.readline() are used. (This means that by importing readline, on systems that support it, the interpreter will automatically support Emacs-like line editing and command-history keystrokes.)

Cmd 예

cmd 모듈은 주로 사용자가 대화식으로 프로그램을 사용할 수 있도록 하는 사용자 정의 셸을 만드는 데 유용합니다.

이 섹션에서는 turtle 모듈의 몇 가지 명령을 중심으로 셸을 작성하는 방법에 대한 간단한 예를 제공합니다.

Basic turtle commands such as forward() are added to a Cmd subclass with method named do_forward(). The argument is converted to a number and dispatched to the turtle module. The docstring is used in the help utility provided by the shell.

The example also includes a basic record and playback facility implemented with the precmd() method which is responsible for converting the input to lowercase and writing the commands to a file. The do_playback() method reads the file and adds the recorded commands to the cmdqueue for immediate playback:

import cmd, sys
from turtle import *

class TurtleShell(cmd.Cmd):
    intro = 'Welcome to the turtle shell.   Type help or ? to list commands.\n'
    prompt = '(turtle) '
    file = None

    # ----- basic turtle commands -----
    def do_forward(self, arg):
        'Move the turtle forward by the specified distance:  FORWARD 10'
        forward(*parse(arg))
    def do_right(self, arg):
        'Turn turtle right by given number of degrees:  RIGHT 20'
        right(*parse(arg))
    def do_left(self, arg):
        'Turn turtle left by given number of degrees:  LEFT 90'
        left(*parse(arg))
    def do_goto(self, arg):
        'Move turtle to an absolute position with changing orientation.  GOTO 100 200'
        goto(*parse(arg))
    def do_home(self, arg):
        'Return turtle to the home position:  HOME'
        home()
    def do_circle(self, arg):
        'Draw circle with given radius an options extent and steps:  CIRCLE 50'
        circle(*parse(arg))
    def do_position(self, arg):
        'Print the current turtle position:  POSITION'
        print('Current position is %d %d\n' % position())
    def do_heading(self, arg):
        'Print the current turtle heading in degrees:  HEADING'
        print('Current heading is %d\n' % (heading(),))
    def do_color(self, arg):
        'Set the color:  COLOR BLUE'
        color(arg.lower())
    def do_undo(self, arg):
        'Undo (repeatedly) the last turtle action(s):  UNDO'
    def do_reset(self, arg):
        'Clear the screen and return turtle to center:  RESET'
        reset()
    def do_bye(self, arg):
        'Stop recording, close the turtle window, and exit:  BYE'
        print('Thank you for using Turtle')
        self.close()
        bye()
        return True

    # ----- record and playback -----
    def do_record(self, arg):
        'Save future commands to filename:  RECORD rose.cmd'
        self.file = open(arg, 'w')
    def do_playback(self, arg):
        'Playback commands from a file:  PLAYBACK rose.cmd'
        self.close()
        with open(arg) as f:
            self.cmdqueue.extend(f.read().splitlines())
    def precmd(self, line):
        line = line.lower()
        if self.file and 'playback' not in line:
            print(line, file=self.file)
        return line
    def close(self):
        if self.file:
            self.file.close()
            self.file = None

def parse(arg):
    'Convert a series of zero or more numbers to an argument tuple'
    return tuple(map(int, arg.split()))

if __name__ == '__main__':
    TurtleShell().cmdloop()

다음은 도움말 기능과, 명령을 반복하기 위해 빈 줄을 사용하는 방법과, 간단한 녹화와 재생기능을 보여주기 위해 turtle 셀을 사용한 예제 세션입니다:

Welcome to the turtle shell.   Type help or ? to list commands.

(turtle) ?

Documented commands (type help <topic>):
========================================
bye     color    goto     home  playback  record  right
circle  forward  heading  left  position  reset   undo

(turtle) help forward
Move the turtle forward by the specified distance:  FORWARD 10
(turtle) record spiral.cmd
(turtle) position
Current position is 0 0

(turtle) heading
Current heading is 0

(turtle) reset
(turtle) circle 20
(turtle) right 30
(turtle) circle 40
(turtle) right 30
(turtle) circle 60
(turtle) right 30
(turtle) circle 80
(turtle) right 30
(turtle) circle 100
(turtle) right 30
(turtle) circle 120
(turtle) right 30
(turtle) circle 120
(turtle) heading
Current heading is 180

(turtle) forward 100
(turtle)
(turtle) right 90
(turtle) forward 100
(turtle)
(turtle) right 90
(turtle) forward 400
(turtle) right 90
(turtle) forward 500
(turtle) right 90
(turtle) forward 400
(turtle) right 90
(turtle) forward 300
(turtle) playback spiral.cmd
Current position is 0 0

Current heading is 0

Current heading is 180

(turtle) bye
Thank you for using Turtle

shlex — Simple lexical analysis

소스 코드: Lib/shlex.py [https://github.com/python/cpython/tree/main/Lib/shlex.py]

shlex 클래스를 사용하면 유닉스 셸과 유사한 간단한 구문에 대한 어휘 분석기를 쉽게 작성할 수 있습니다. 이것은 미니 언어를 작성하거나 (예를 들어 파이썬 응용 프로그램을 위한 실행 제어 파일에서), 인용된 문자열을 구문 분석할 때 유용합니다.

shlex 모듈은 다음 함수를 정의합니다:

shlex.split(s, comments=False, posix=True)

셸과 비슷한 문법을 사용하여 문자열 s를 분할합니다. comments가 False(기본값)이면, 지정된 문자열의 주석 구문 분석이 비활성화됩니다 (shlex 인스턴스의 commenters 어트리뷰트를 빈 문자열로 설정합니다). 이 함수는 기본적으로 POSIX 모드로 작동하지만, posix 인자가 거짓이면 비 POSIX 모드를 사용합니다.

버전 3.12에서 변경: Passing None for s argument now raises an exception, rather than reading sys.stdin.

shlex.join(split_command)

리스트 split_command의 토큰을 이어붙이고 문자열을 반환합니다. 이 함수는 split()의 역함수입니다.

>>> from shlex import join
>>> print(join(['echo', '-n', 'Multiple words']))
echo -n 'Multiple words'

반환된 값은 주입 취약점(injection vulnerabilities)으로부터 보호하기 위해 셸 이스케이프 처리됩니다 (quote()를 참조하십시오).

Added in version 3.8.

shlex.quote(s)

셸 이스케이프 된 문자열 s를 반환합니다. 반환된 값은 (리스트를 사용할 수 없는 경우) 셸 명령 줄에서 하나의 토큰으로 안전하게 사용할 수 있는 문자열입니다.

경고

The shlex module is only designed for Unix shells.

The quote() function is not guaranteed to be correct on non-POSIX compliant shells or shells from other operating systems such as Windows. Executing commands quoted by this module on such shells can open up the possibility of a command injection vulnerability.

Consider using functions that pass command arguments with lists such as subprocess.run() with shell=False.

이 관용구는 안전하지 않습니다:

>>> filename = 'somefile; rm -rf ~'
>>> command = 'ls -l {}'.format(filename)
>>> print(command)  # executed by a shell: boom!
ls -l somefile; rm -rf ~

quote()를 사용하면 보안 허점을 메꿀 수 있습니다:

>>> from shlex import quote
>>> command = 'ls -l {}'.format(quote(filename))
>>> print(command)
ls -l 'somefile; rm -rf ~'
>>> remote_command = 'ssh home {}'.format(quote(command))
>>> print(remote_command)
ssh home 'ls -l '"'"'somefile; rm -rf ~'"'"''

인용(quoting)은 유닉스 셸과 split()과 호환됩니다:

>>> from shlex import split
>>> remote_command = split(remote_command)
>>> remote_command
['ssh', 'home', "ls -l 'somefile; rm -rf ~'"]
>>> command = split(remote_command[-1])
>>> command
['ls', '-l', 'somefile; rm -rf ~']

Added in version 3.3.

shlex 모듈은 다음 클래스를 정의합니다:

class shlex.shlex(instream=None, infile=None, posix=False, punctuation_chars=False)

shlex 인스턴스나 서브 클래스 인스턴스는 어휘 분석기 객체입니다. 존재할 때 초기화 인자는 문자를 어디에서 읽을지를 지정합니다. read()와 readline() 메서드가 있는 파일/스트림류 객체이거나 문자열이어야 합니다. 인자가 없으면 sys.stdin에서 입력을 받습니다. 두 번째 선택적 인자는 파일명 문자열이며, infile 어트리뷰트의 초깃값을 설정합니다. instream 인자가 생략되거나 sys.stdin과 같으면, 이 두 번째 인자의 기본값은 “stdin”입니다. posix 인자는 작동 모드를 정의합니다: posix가 참이 아닐 때 (기본값), shlex 인스턴스는 호환 모드에서 작동합니다. POSIX 모드에서 작동할 때, shlex는 가능한 한 POSIX 셸 구문 분석 규칙에 가깝도록 시도합니다. punctuation_chars 인자는 동작을 실제 셸이 구문 분석하는 방식에 더 가깝게 만드는 방법을 제공합니다. 이것은 여러 종류의 값을 취할 수 있습니다: 기본값 False는 파이썬 3.5와 이전 버전에서의 동작을 유지합니다. True로 설정되면, 문자 ();<>|&의 구문 분석이 변경됩니다: 이러한 문자(구두(punctuation) 문자로 간주합니다)의 모든 연속은 단일 토큰으로 반환됩니다. 비어 있지 않은 문자열로 설정하면, 해당 문자는 구두(punctuation) 문자로 사용됩니다. punctuation_chars에 나타나는 wordchars 어트리뷰트의 문자는 wordchars에서 제거됩니다. 자세한 정보는 셸과의 호환성 향상을 참조하십시오. punctuation_chars는 shlex 인스턴스 생성 시에만 설정할 수 있으며 나중에 수정할 수 없습니다.

버전 3.6에서 변경: punctuation_chars 매개 변수가 추가되었습니다.

더 보기

모듈 configparser

윈도우 .ini 파일과 유사한 구성 파일 구문 분석기.

shlex 객체

shlex 인스턴스에는 다음과 같은 메서드가 있습니다:

shlex.get_token()

토큰을 반환합니다. push_token()을 사용하여 토큰이 스택(stack) 되었으면, 스택에서 토큰을 팝(pop) 합니다. 그렇지 않으면, 입력 스트림에서 하나를 읽습니다. 읽기가 즉시 파일 끝을 만나면, eof가 반환됩니다 (POSIX 모드가 아니면 빈 문자열 (''), POSIX 모드이면 None).

shlex.push_token(str)

인자를 토큰 스택으로 푸시(push)합니다.

shlex.read_token()

원시 토큰을 읽습니다. 푸시백 스택을 무시하고, 소스 요청(source requests)을 해석하지 않습니다. (이것은 일반적으로 유용한 진입점이 아니며, 단지 완전성을 위해 여기에서 설명합니다.)

shlex.sourcehook(filename)

shlex가 소스 요청(아래 source를 참조하십시오)을 감지할 때 이 메서드에는 다음 토큰이 인자로 제공되고 파일명과 열린 파일류 객체로 구성된 튜플을 반환해야 합니다.

일반적으로, 이 메서드는 먼저 인자에서 인용(quotes)을 제거합니다. 결과가 절대 경로명이거나 유효한 이전 소스 요청이 없거나 이전 소스가 스트림(가령 sys.stdin)이면 결과는 그대로 유지됩니다. 그렇지 않으면, 결과가 상대 경로명이면 소스 포함 스택에서 파일 바로 앞에 있는 파일의 이름의 디렉터리 부분을 앞에 붙입니다 (이 동작은 C 전처리기가 #include "file.h"를 처리하는 방식과 유사합니다).

조작 결과는 파일명으로 취급되고, 튜플의 첫 번째 구성 요소로 반환되며, 이것에 open()이 호출되어 두 번째 구성 요소를 산출합니다. (참고: 이것은 인스턴스 초기화의 인자 순서와 반대입니다!)

이 훅은 디렉터리 검색 경로, 파일 확장자 추가 및 기타 네임 스페이스 해킹을 구현하는 데 사용할 수 있도록 노출됩니다. 해당 ‘닫기’ 훅은 없지만, shlex 인스턴스는 소스 입력 스트림이 EOF를 반환할 때 그것의 close() 메서드를 호출합니다.

소스 스태킹을 더 명시적으로 제어하려면, push_source()와 pop_source() 메서드를 사용하십시오.

shlex.push_source(newstream, newfile=None)

입력 소스 스트림을 입력 스택으로 푸시합니다. filename 인자가 지정되면 나중에 에러 메시지에 사용할 수 있습니다. 이것은 sourcehook() 메서드에 의해 내부적으로 사용되는 것과 같은 메서드입니다.

shlex.pop_source()

마지막으로 푸시 된 입력 소스를 입력 스택에서 팝 합니다. 이는 어휘 분석기가 스택 된 입력 스트림에서 EOF에 도달할 때 내부적으로 사용되는 것과 같은 메서드입니다.

shlex.error_leader(infile=None, lineno=None)

이 메서드는 유닉스 C 컴파일러 에러 레이블 형식으로 에러 메시지 리더를 생성합니다; 형식은 '"%s", line %d: '이며, 여기서 %s는 현재 소스 파일의 이름으로 치환되고 %d는 현재 입력 줄 번호로 치환됩니다 (선택적 인자를 사용하여 이를 재정의할 수 있습니다).

이 편리 메서드는 shlex 사용자가 Emacs와 기타 유닉스 도구가 이해할 수 있는 표준의 구문 분석 가능한 형식으로 에러 메시지를 생성하도록 권장하기 위해 제공됩니다.

shlex 서브 클래스의 인스턴스에는 어휘 분석을 제어하거나 디버깅에 사용할 수 있는 일부 공용 인스턴스 변수가 있습니다:

shlex.commenters

주석을 시작하는 것으로 인식되는 문자열. 주석 시작부터 줄 끝까지의 모든 문자는 무시됩니다. 기본적으로 '#' 만 포함합니다.

shlex.wordchars

다중 문자 토큰에 누적될 문자들의 문자열. 기본적으로, 모든 ASCII 영숫자와 밑줄이 포함됩니다. POSIX 모드에서는, 라틴-1 집합의 악센트 부호 문자도 포함됩니다. punctuation_chars가 비어 있지 않으면, 파일명 명세와 명령 줄 매개 변수에 나타날 수 있는 문자 ~-./*?=도 이 어트리뷰트에 포함되며, punctuation_chars에 있는 문자는 wordchars에 있으면 제거됩니다. whitespace_split이 True로 설정되면, 이것은 효과가 없습니다.

shlex.whitespace

공백으로 간주하여 건너뛸 문자들. 공백은 토큰의 경계를 만듭니다. 기본적으로, 스페이스, 탭, 줄 바꿈 및 캐리지 리턴이 포함됩니다.

shlex.escape

이스케이프로 간주하는 문자들. POSIX 모드에서만 사용되며, 기본적으로 '\' 만 포함합니다.

shlex.quotes

문자열 인용으로 간주하는 문자들. 같은 인용을 다시 만날 때까지 토큰이 누적됩니다 (따라서, 다른 인용 유형은 셸에서와같이 서로를 보호합니다). 기본적으로, ASCII 작은따옴표와 큰따옴표가 포함됩니다.

shlex.escapedquotes

escape에 정의된 이스케이프 문자를 해석하는 quotes의 문자들. 이것은 POSIX 모드에서만 사용되며, 기본적으로 '"' 만 포함합니다.

shlex.whitespace_split

True이면, 토큰은 공백으로만 분할됩니다. 예를 들어, shlex로 명령 줄을 구문 분석하고 셸 인자와 유사한 방식으로 토큰을 가져오는 데 유용합니다. punctuation_chars와 함께 사용하면, 토큰은 그 문자들 외에도 공백으로 분할됩니다.

버전 3.8에서 변경: punctuation_chars 어트리뷰트가 whitespace_split 어트리뷰트와 호환되었습니다.

shlex.infile

클래스 인스턴스화 시점에 처음 설정되거나 이후 소스 요청으로 스택 된 현재 입력 파일의 이름. 에러 메시지를 구성할 때 이를 조사하는 것이 유용할 수 있습니다.

shlex.instream

이 shlex 인스턴스가 문자를 읽고 있는 입력 스트림.

shlex.source

이 어트리뷰트는 기본적으로 None입니다. 문자열을 대입하면, 해당 문자열은 여러 셸의 source 키워드와 유사한 어휘 수준 포함 요청으로 인식됩니다. 즉, 바로 다음 토큰이 파일명으로 열리고 그 스트림에서 입력을 EOF까지 취합니다, 이 시점에서 해당 스트림의 close() 메서드가 호출되고 입력 소스는 다시 원래 입력 스트림이 됩니다. 소스 요청은 임의의 수준 깊이로 스택 될 수 있습니다.

shlex.debug

이 어트리뷰트가 숫자이고 1 이상이면, shlex 인스턴스는 자신의 동작에 대한 자세한 진행 출력을 인쇄합니다. 이것을 사용해야 하면, 세부 사항을 배우기 위해 모듈 소스 코드를 읽을 수 있습니다.

shlex.lineno

소스 줄 번호 (지금까지 본 줄 넘김 개수에 1을 더한 것).

shlex.token

토큰 버퍼. 예외를 잡을 때 이를 조사하는 것이 유용 할 수 있습니다.

shlex.eof

파일 끝을 판단하는 데 사용되는 토큰. POSIX 모드가 아닐 때 빈 문자열 (''), POSIX 모드일 때 None으로 설정됩니다.

shlex.punctuation_chars

읽기 전용 프로퍼티. 구두 부호로 간주할 문자들. 구두 부호 문자들은 단일 토큰으로 반환됩니다. 그러나, 아무런 의미 유효성 검사도 수행되지 않음에 유의하십시오: 예를 들어 ‘>>>’는 셸에서 인식되지 않더라도 토큰으로 반환될 수 있습니다.

Added in version 3.6.

구문 분석 규칙

비 POSIX 모드에서 작동할 때, shlex는 다음 규칙을 따르려고 합니다.

인용 문자는 단어 내에서 인식되지 않습니다 (Do"Not"Separate는 단일 단어 Do"Not"Separate로 구문 분석됩니다);

이스케이프 문자는 인식되지 않습니다;

인용으로 묶인 문자들은 인용 안에 있는 모든 문자의 리터럴 값을 유지합니다;

인용을 닫는 것은 단어를 분리합니다 ("Do"Separate는 "Do"와 Separate로 구문 분석됩니다);

whitespace_split가 False이면, 단어 문자, 공백 또는 인용으로 선언되지 않은 모든 문자는 단일 문자 토큰으로 반환됩니다. True이면, shlex는 공백으로 만 단어를 분리합니다;

EOF는 빈 문자열('')로 알립니다;

인용된 경우에도 빈 문자열을 구문 분석할 수 없습니다.

POSIX 모드에서 작동할 때, shlex는 다음 구문 분석 규칙을 따르려고 합니다.

인용은 제거되고, 단어를 분리하지 않습니다 ("Do"Not"Separate"는 단일 단어 DoNotSeparate로 구문 분석됩니다);

인용되지 않은 이스케이프 문자(예를 들어 '\')는 다음에 오는 문자의 리터럴 값을 유지합니다;

escapedquotes의 일부가 아닌 인용으로 묶인 문자(예를 들어 "'")는 인용 안에 있는 모든 문자의 리터럴 값을 유지합니다;

escapedquotes의 일부인 인용으로 묶인 문자(예를 들어 '"')는 escape에서 언급된 문자를 제외하고 인용 안에 있는 모든 문자의 리터럴 값을 유지합니다. 이스케이프 문자는 사용 중인 인용이나 이스케이프 문자 자체가 뒤에 오는 경우에만 특별한 의미를 유지합니다. 그렇지 않으면 이스케이프 문자는 일반 문자로 간주합니다.

EOF는 None 값으로 알립니다;

인용된 빈 문자열('')이 허용됩니다.

셸과의 호환성 향상

Added in version 3.6.

shlex 클래스는 bash, dash 및 sh와 같은 일반적인 유닉스 셸에서 수행하는 구문 분석과 호환됩니다. 이 호환성을 이용하려면, 생성자에서 punctuation_chars 인자를 지정하십시오. 기본값은 False이며, 3.6 이전 동작을 유지합니다. 그러나, True로 설정되면, 문자 ();<>|&의 구문 분석이 변경됩니다: 이러한 문자의 연속은 단일 토큰으로 반환됩니다. 이것은 셸에 대한 전체 파서로는 부족하지만 (여러 종류의 셀이 있음을 고려할 때, 표준 라이브러리의 범위를 벗어납니다), 이것이 없을 때보다 명령 줄 처리를 더 쉽게 수행할 수 있도록 합니다. 예시하기 위해, 다음 코드 조각에서 차이점을 볼 수 있습니다:

>>> import shlex
>>> text = "a && b; c && d || e; f >'abc'; (def \"ghi\")"
>>> s = shlex.shlex(text, posix=True)
>>> s.whitespace_split = True
>>> list(s)
['a', '&&', 'b;', 'c', '&&', 'd', '||', 'e;', 'f', '>abc;', '(def', 'ghi)']
>>> s = shlex.shlex(text, posix=True, punctuation_chars=True)
>>> s.whitespace_split = True
>>> list(s)
['a', '&&', 'b', ';', 'c', '&&', 'd', '||', 'e', ';', 'f', '>', 'abc', ';',
'(', 'def', 'ghi', ')']

물론, 셸에 유효하지 않은 토큰이 반환되며, 반환된 토큰에 대해 여러분 자신의 에러 검사를 구현해야 합니다.

punctuation_chars 매개 변수의 값으로 True를 전달하는 대신, 특정 문자가 포함된 문자열을 전달하면 구두 부호를 구성하는 문자를 판별하는 데 사용됩니다. 예를 들면:

>>> import shlex
>>> s = shlex.shlex("a && b || c", punctuation_chars="|")
>>> list(s)
['a', '&', '&', 'b', '||', 'c']

참고

punctuation_chars가 지정되면, wordchars 어트리뷰트는 문자 ~-./*?=로 보강됩니다. 이러한 문자는 파일 이름(와일드카드를 포함해서)과 명령 줄 인자(예를 들어 --color=auto)에 나타날 수 있기 때문입니다. 그래서:

>>> import shlex
>>> s = shlex.shlex('~/a && b-c --color=auto || d *.py?',
...                 punctuation_chars=True)
>>> list(s)
['~/a', '&&', 'b-c', '--color=auto', '||', 'd', '*.py?']

그러나, 가능한 한 가깝게 셸과 일치하려면, punctuation_chars를 사용할 때 항상 posix와 whitespace_split를 사용하는 것이 좋습니다, 이는 wordchars를 완전히 무효로 합니다.

최상의 효과를 얻으려면, punctuation_chars를 posix=True와 함께 설정해야 합니다. (posix=False가 shlex의 기본값임에 유의하십시오.)

Tk를 사용한 그래픽 사용자 인터페이스

Tk/Tcl has long been an integral part of Python. It provides a robust and platform independent windowing toolkit, that is available to Python programmers using the tkinter package, and its extension, the tkinter.ttk module.

The tkinter package is a thin object-oriented layer on top of Tcl/Tk. To use tkinter, you don’t need to write Tcl code, but you will need to consult the Tk documentation, and occasionally the Tcl documentation. tkinter is a set of wrappers that implement the Tk widgets as Python classes.

tkinter’s chief virtues are that it is fast, and that it usually comes bundled with Python. Although its standard documentation is weak, good material is available, which includes: references, tutorials, a book and others. tkinter is also famous for having an outdated look and feel, which has been vastly improved in Tk 8.5. Nevertheless, there are many other GUI libraries that you could be interested in. The Python wiki lists several alternative GUI frameworks and tools [https://wiki.python.org/moin/GuiProgramming].

tkinter — Python interface to Tcl/Tk

Architecture

Tkinter 모듈

Tk

tk

master

children

Tcl()

Tkinter 구명조끼

A Hello World Program

Important Tk Concepts

Understanding How Tkinter Wraps Tcl/Tk

How do I…? What option does…?

Navigating the Tcl/Tk Reference Manual

Threading model

간편한 레퍼런스

옵션 설정

패커

패커 옵션

위젯 변수 결합하기

창 관리자

Tk 옵션 데이터형

바인딩과 이벤트

index 매개 변수

이미지

파일 처리기

createfilehandler()

deletefilehandler()

READABLE

WRITABLE

EXCEPTION

tkinter.colorchooser — Color choosing dialog

Chooser

askcolor()

tkinter.font — Tkinter font wrapper

NORMAL

BOLD

ITALIC

ROMAN

Font

actual()

cget()

config()

copy()

measure()

metrics()

families()

names()

nametofont()

Tkinter 대화 상자

tkinter.simpledialog — 표준 Tkinter 입력 대화 상자

askfloat()

askinteger()

askstring()

Dialog

body()

buttonbox()

tkinter.filedialog — 파일 선택 대화 상자

네이티브 로드/저장 대화 상자

askopenfile()

askopenfiles()

asksaveasfile()

askopenfilename()

askopenfilenames()

asksaveasfilename()

askdirectory()

Open

SaveAs

Directory

FileDialog

cancel_command()

dirs_double_event()

dirs_select_event()

files_double_event()

files_select_event()

filter_command()

get_filter()

get_selection()

go()

ok_event()

quit()

set_filter()

set_selection()

LoadFileDialog

ok_command()

SaveFileDialog

ok_command()

tkinter.commondialog — 대화창 템플릿

Dialog

show()

tkinter.messagebox — Tkinter message prompts

Message

show()

showinfo()

showwarning()

showerror()

askquestion()

askokcancel()

askretrycancel()

askyesno()

askyesnocancel()

ABORT

RETRY

IGNORE

OK

CANCEL

YES

NO

ABORTRETRYIGNORE

OKCANCEL

RETRYCANCEL

YESNO

YESNOCANCEL

ERROR

INFO

QUESTION

WARNING

tkinter.scrolledtext — Scrolled Text Widget

ScrolledText

frame

vbar

tkinter.dnd — Drag and drop support

DndHandler

cancel()

finish()

on_motion()

on_release()

dnd_start()

tkinter.ttk — Tk themed widgets

Ttk 사용하기

Ttk 위젯

Widget

표준 옵션

스크롤 가능한 위젯 옵션

레이블 옵션

호환성 옵션

위젯 상태

ttk.Widget

Widget

identify()

instate()

state()

Combobox

옵션

가상 이벤트

ttk.Combobox

Combobox

current()

get()

set()

Spinbox

옵션

가상 이벤트

ttk.Spinbox

Spinbox

get()

set()

Notebook

옵션

탭 옵션

탭 식별자

가상 이벤트

ttk.Notebook

Notebook

add()

forget()

hide()

identify()

index()

insert()

select()

tab()

tabs()

enable_traversal()

Progressbar

옵션

ttk.Progressbar

Progressbar

start()

step()

stop()

Separator

옵션

Sizegrip

플랫폼별 노트

버그

Treeview

옵션

항목 옵션

태그 옵션

열 식별자

가상 이벤트

ttk.Treeview

Treeview

bbox()

get_children()

set_children()

column()

delete()

detach()

exists()

focus()

heading()

identify()

identify_row()

identify_column()

identify_region()

identify_element()

index()

insert()

item()

move()

next()

parent()

prev()

reattach()

see()

selection()

selection_set()

selection_add()

selection_remove()

selection_toggle()

set()

tag_bind()

tag_configure()

tag_has()

xview()

yview()

Ttk 스타일링

Style

configure()

map()

lookup()

layout()

element_create()

element_names()

element_options()

theme_create()

theme_settings()

theme_names()

theme_use()

레이아웃

IDLE

메뉴

File 메뉴 (셸과 편집기)

Edit 메뉴 (셸과 편집기)

Format 메뉴 (편집기 창 전용)

Run 메뉴 (편집기 창 전용)

Shell 메뉴 (셸 창 전용)

Debug 메뉴 (셸 창 전용)

Options 메뉴 (셸과 편집기)

Window 메뉴 (셸과 편집기)

Help 메뉴 (셸과 편집기)

Context menus

Editing and Navigation

편집기 창

키 바인딩

자동 들여쓰기

Search and Replace

완성

콜팁

코드 컨텍스트

Shell window

텍스트 색상

Startup and Code Execution

명령 줄 사용법

시작 실패

사용자 코드 실행하기

셸의 사용자 출력

tkinter 응용 프로그램 개발하기

서브 프로세스 없이 실행하기

Help and Preferences

도움말 소스

환경 설정

macOS의 IDLE

확장

idlelib

tkinter — Python interface to Tcl/Tk

소스 코드: Lib/tkinter/__init__.py [https://github.com/python/cpython/tree/main/Lib/tkinter/__init__.py]

The tkinter package (“Tk interface”) is the standard Python interface to the Tcl/Tk GUI toolkit. Both Tk and tkinter are available on most Unix platforms, including macOS, as well as on Windows systems.

명령 줄에서 python -m tkinter를 실행하면 간단한 Tk 인터페이스를 보여주는 창을 열어, tkinter가 시스템에 제대로 설치되었는지 알 수 있도록 하고, 설치된 Tcl/Tk 버전을 보여주기 때문에, 그 버전에 해당하는 Tcl/Tk 설명서를 읽을 수 있습니다.

Tkinter supports a range of Tcl/Tk versions, built either with or without thread support. The official Python binary release bundles Tcl/Tk 8.6 threaded. See the source code for the _tkinter module for more information about supported versions.

Tkinter is not a thin wrapper, but adds a fair amount of its own logic to make the experience more pythonic. This documentation will concentrate on these additions and changes, and refer to the official Tcl/Tk documentation for details that are unchanged.

참고

Tcl/Tk 8.5 (2007) introduced a modern set of themed user interface components along with a new API to use them. Both old and new APIs are still available. Most documentation you will find online still uses the old API and can be woefully outdated.

더 보기

TkDocs [https://tkdocs.com/]

Extensive tutorial on creating user interfaces with Tkinter. Explains key concepts, and illustrates recommended approaches using the modern API.

Tkinter 8.5 reference: a GUI for Python [https://www.tkdocs.com/shipman/]

Reference documentation for Tkinter 8.5 detailing available classes, methods, and options.

Tcl/Tk Resources:

Tk commands [https://www.tcl.tk/man/tcl8.6/TkCmd/contents.htm]

Comprehensive reference to each of the underlying Tcl/Tk commands used by Tkinter.

Tcl/Tk Home Page [https://www.tcl.tk]

Additional documentation, and links to Tcl/Tk core development.

Books:

Modern Tkinter for Busy Python Developers [https://tkdocs.com/book.html]

By Mark Roseman. (ISBN 978-1999149567)

Python GUI programming with Tkinter [https://www.packtpub.com/en-us/product/python-gui-programming-with-tkinter-9781788835886]

By Alan D. Moore. (ISBN 978-1788835886)

Programming Python [https://learning-python.com/about-pp4e.html]

By Mark Lutz; has excellent coverage of Tkinter. (ISBN 978-0596158101)

Tcl and the Tk Toolkit (2nd edition) [https://www.amazon.com/exec/obidos/ASIN/032133633X]

By John Ousterhout, inventor of Tcl/Tk, and Ken Jones; does not cover Tkinter. (ISBN 978-0321336330)

Architecture

Tcl/Tk is not a single library but rather consists of a few distinct modules, each with separate functionality and its own official documentation. Python’s binary releases also ship an add-on module together with it.

Tcl

Tcl is a dynamic interpreted programming language, just like Python. Though it can be used on its own as a general-purpose programming language, it is most commonly embedded into C applications as a scripting engine or an interface to the Tk toolkit. The Tcl library has a C interface to create and manage one or more instances of a Tcl interpreter, run Tcl commands and scripts in those instances, and add custom commands implemented in either Tcl or C. Each interpreter has an event queue, and there are facilities to send events to it and process them. Unlike Python, Tcl’s execution model is designed around cooperative multitasking, and Tkinter bridges this difference (see Threading model for details).

Tk

Tk is a Tcl package [https://wiki.tcl-lang.org/37432] implemented in C that adds custom commands to create and manipulate GUI widgets. Each Tk object embeds its own Tcl interpreter instance with Tk loaded into it. Tk’s widgets are very customizable, though at the cost of a dated appearance. Tk uses Tcl’s event queue to generate and process GUI events.

Ttk

Themed Tk (Ttk) is a newer family of Tk widgets that provide a much better appearance on different platforms than many of the classic Tk widgets. Ttk is distributed as part of Tk, starting with Tk version 8.5. Python bindings are provided in a separate module, tkinter.ttk.

Internally, Tk and Ttk use facilities of the underlying operating system, i.e., Xlib on Unix/X11, Cocoa on macOS, GDI on Windows.

When your Python application uses a class in Tkinter, e.g., to create a widget, the tkinter module first assembles a Tcl/Tk command string. It passes that Tcl command string to an internal _tkinter binary module, which then calls the Tcl interpreter to evaluate it. The Tcl interpreter will then call into the Tk and/or Ttk packages, which will in turn make calls to Xlib, Cocoa, or GDI.

Tkinter 모듈

Support for Tkinter is spread across several modules. Most applications will need the main tkinter module, as well as the tkinter.ttk module, which provides the modern themed widget set and API:

from tkinter import *
from tkinter import ttk

class tkinter.Tk(screenName=None, baseName=None, className='Tk', useTk=True, sync=False, use=None)

Construct a toplevel Tk widget, which is usually the main window of an application, and initialize a Tcl interpreter for this widget. Each instance has its own associated Tcl interpreter.

The Tk class is typically instantiated using all default values. However, the following keyword arguments are currently recognized:

screenName

When given (as a string), sets the DISPLAY environment variable. (X11 only)

baseName

Name of the profile file. By default, baseName is derived from the program name (sys.argv[0]).

className

Name of the widget class. Used as a profile file and also as the name with which Tcl is invoked (argv0 in interp).

useTk

If True, initialize the Tk subsystem. The tkinter.Tcl() function sets this to False.

sync

If True, execute all X server commands synchronously, so that errors are reported immediately. Can be used for debugging. (X11 only)

use

Specifies the id of the window in which to embed the application, instead of it being created as an independent toplevel window. id must be specified in the same way as the value for the -use option for toplevel widgets (that is, it has a form like that returned by winfo_id()).

Note that on some platforms this will only work correctly if id refers to a Tk frame or toplevel that has its -container option enabled.

Tk reads and interprets profile files, named .className.tcl and .baseName.tcl, into the Tcl interpreter and calls exec() on the contents of .className.py and .baseName.py. The path for the profile files is the HOME environment variable or, if that isn’t defined, then os.curdir.

tk

The Tk application object created by instantiating Tk. This provides access to the Tcl interpreter. Each widget that is attached the same instance of Tk has the same value for its tk attribute.

master

The widget object that contains this widget. For Tk, the master is None because it is the main window. The terms master and parent are similar and sometimes used interchangeably as argument names; however, calling winfo_parent() returns a string of the widget name whereas master returns the object. parent/child reflects the tree-like relationship while master/slave reflects the container structure.

children

The immediate descendants of this widget as a dict with the child widget names as the keys and the child instance objects as the values.

tkinter.Tcl(screenName=None, baseName=None, className='Tk', useTk=False)

Tcl() 함수는 Tk 서브 시스템을 초기화하지 않는다는 것을 제외하고는, Tk 클래스에 의해 만들어지는 것과 비슷한 객체를 만드는 팩토리 함수입니다. 불필요한 최상위 창을 만들고 싶지 않거나 만들 수 없는 (가령 X 서버가 없는 유닉스/리눅스 시스템) 환경에서 Tcl 인터프리터를 구동할 때 가장 유용합니다. Tcl() 객체에 의해 만들어진 객체는 loadtk() 메서드를 호출하여 만들어지는 최상위 창(과 초기화된 Tk 서브 시스템)을 가질 수 있습니다.

The modules that provide Tk support include:

tkinter

Main Tkinter module.

tkinter.colorchooser

사용자가 색상을 선택할 수 있게 하는 대화 상자.

tkinter.commondialog

여기에 나열된 다른 모듈에 정의된 대화 상자의 베이스 기본 클래스.

tkinter.filedialog

사용자가 열거나 저장할 파일을 지정할 수 있도록 하는 일반 대화 상자입니다.

tkinter.font

글꼴과 관련된 작업에 도움이 되는 유틸리티.

tkinter.messagebox

표준 Tk 대화 상자에 액세스합니다.

tkinter.scrolledtext

세로 스크롤 막대가 내장된 Text 위젯.

tkinter.simpledialog

기본 대화 상자와 편리 함수.

tkinter.ttk

Themed widget set introduced in Tk 8.5, providing modern alternatives for many of the classic widgets in the main tkinter module.

Additional modules:

_tkinter

A binary module that contains the low-level interface to Tcl/Tk. It is automatically imported by the main tkinter module, and should never be used directly by application programmers. It is usually a shared library (or DLL), but might in some cases be statically linked with the Python interpreter.

idlelib

Python’s Integrated Development and Learning Environment (IDLE). Based on tkinter.

tkinter.constants

Symbolic constants that can be used in place of strings when passing various parameters to Tkinter calls. Automatically imported by the main tkinter module.

tkinter.dnd

(experimental) Drag-and-drop support for tkinter. This will become deprecated when it is replaced with the Tk DND.

turtle

Tk 창에서의 터틀(turtle) 그래픽.

Tkinter 구명조끼

This section is not designed to be an exhaustive tutorial on either Tk or Tkinter. For that, refer to one of the external resources noted earlier. Instead, this section provides a very quick orientation to what a Tkinter application looks like, identifies foundational Tk concepts, and explains how the Tkinter wrapper is structured.

The remainder of this section will help you to identify the classes, methods, and options you’ll need in your Tkinter application, and where to find more detailed documentation on them, including in the official Tcl/Tk reference manual.

A Hello World Program

We’ll start by walking through a “Hello World” application in Tkinter. This isn’t the smallest one we could write, but has enough to illustrate some key concepts you’ll need to know.

from tkinter import *
from tkinter import ttk
root = Tk()
frm = ttk.Frame(root, padding=10)
frm.grid()
ttk.Label(frm, text="Hello World!").grid(column=0, row=0)
ttk.Button(frm, text="Quit", command=root.destroy).grid(column=1, row=0)
root.mainloop()

After the imports, the next line creates an instance of the Tk class, which initializes Tk and creates its associated Tcl interpreter. It also creates a toplevel window, known as the root window, which serves as the main window of the application.

The following line creates a frame widget, which in this case will contain a label and a button we’ll create next. The frame is fit inside the root window.

The next line creates a label widget holding a static text string. The grid() method is used to specify the relative layout (position) of the label within its containing frame widget, similar to how tables in HTML work.

A button widget is then created, and placed to the right of the label. When pressed, it will call the destroy() method of the root window.

Finally, the mainloop() method puts everything on the display, and responds to user input until the program terminates.

Important Tk Concepts

Even this simple program illustrates the following key Tk concepts:

widgets

A Tkinter user interface is made up of individual widgets. Each widget is represented as a Python object, instantiated from classes like ttk.Frame, ttk.Label, and ttk.Button.

widget hierarchy

Widgets are arranged in a hierarchy. The label and button were contained within a frame, which in turn was contained within the root window. When creating each child widget, its parent widget is passed as the first argument to the widget constructor.

configuration options

Widgets have configuration options, which modify their appearance and behavior, such as the text to display in a label or button. Different classes of widgets will have different sets of options.

geometry management

Widgets aren’t automatically added to the user interface when they are created. A geometry manager like grid controls where in the user interface they are placed.

event loop

Tkinter reacts to user input, changes from your program, and even refreshes the display only when actively running an event loop. If your program isn’t running the event loop, your user interface won’t update.

Understanding How Tkinter Wraps Tcl/Tk

When your application uses Tkinter’s classes and methods, internally Tkinter is assembling strings representing Tcl/Tk commands, and executing those commands in the Tcl interpreter attached to your application’s Tk instance.

Whether it’s trying to navigate reference documentation, trying to find the right method or option, adapting some existing code, or debugging your Tkinter application, there are times that it will be useful to understand what those underlying Tcl/Tk commands look like.

To illustrate, here is the Tcl/Tk equivalent of the main part of the Tkinter script above.

ttk::frame .frm -padding 10
grid .frm
grid [ttk::label .frm.lbl -text "Hello World!"] -column 0 -row 0
grid [ttk::button .frm.btn -text "Quit" -command "destroy ."] -column 1 -row 0

Tcl’s syntax is similar to many shell languages, where the first word is the command to be executed, with arguments to that command following it, separated by spaces. Without getting into too many details, notice the following:

The commands used to create widgets (like ttk::frame) correspond to widget classes in Tkinter.

Tcl widget options (like -text) correspond to keyword arguments in Tkinter.

Widgets are referred to by a pathname in Tcl (like .frm.btn), whereas Tkinter doesn’t use names but object references.

A widget’s place in the widget hierarchy is encoded in its (hierarchical) pathname, which uses a . (dot) as a path separator. The pathname for the root window is just . (dot). In Tkinter, the hierarchy is defined not by pathname but by specifying the parent widget when creating each child widget.

Operations which are implemented as separate commands in Tcl (like grid or destroy) are represented as methods on Tkinter widget objects. As you’ll see shortly, at other times Tcl uses what appear to be method calls on widget objects, which more closely mirror what would is used in Tkinter.

How do I…? What option does…?

If you’re not sure how to do something in Tkinter, and you can’t immediately find it in the tutorial or reference documentation you’re using, there are a few strategies that can be helpful.

First, remember that the details of how individual widgets work may vary across different versions of both Tkinter and Tcl/Tk. If you’re searching documentation, make sure it corresponds to the Python and Tcl/Tk versions installed on your system.

When searching for how to use an API, it helps to know the exact name of the class, option, or method that you’re using. Introspection, either in an interactive Python shell or with print(), can help you identify what you need.

To find out what configuration options are available on any widget, call its configure() method, which returns a dictionary containing a variety of information about each object, including its default and current values. Use keys() to get just the names of each option.

btn = ttk.Button(frm, ...)
print(btn.configure().keys())

As most widgets have many configuration options in common, it can be useful to find out which are specific to a particular widget class. Comparing the list of options to that of a simpler widget, like a frame, is one way to do that.

print(set(btn.configure().keys()) - set(frm.configure().keys()))

Similarly, you can find the available methods for a widget object using the standard dir() function. If you try it, you’ll see there are over 200 common widget methods, so again identifying those specific to a widget class is helpful.

print(dir(btn))
print(set(dir(btn)) - set(dir(frm)))

Navigating the Tcl/Tk Reference Manual

As noted, the official Tk commands [https://www.tcl.tk/man/tcl8.6/TkCmd/contents.htm] reference manual (man pages) is often the most accurate description of what specific operations on widgets do. Even when you know the name of the option or method that you need, you may still have a few places to look.

While all operations in Tkinter are implemented as method calls on widget objects, you’ve seen that many Tcl/Tk operations appear as commands that take a widget pathname as its first parameter, followed by optional parameters, e.g.

destroy .
grid .frm.btn -column 0 -row 0

Others, however, look more like methods called on a widget object (in fact, when you create a widget in Tcl/Tk, it creates a Tcl command with the name of the widget pathname, with the first parameter to that command being the name of a method to call).

.frm.btn invoke
.frm.lbl configure -text "Goodbye"

In the official Tcl/Tk reference documentation, you’ll find most operations that look like method calls on the man page for a specific widget (e.g., you’ll find the invoke() method on the ttk::button [https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_button.htm] man page), while functions that take a widget as a parameter often have their own man page (e.g., grid [https://www.tcl.tk/man/tcl8.6/TkCmd/grid.htm]).

You’ll find many common options and methods in the options [https://www.tcl.tk/man/tcl8.6/TkCmd/options.htm] or ttk::widget [https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_widget.htm] man pages, while others are found in the man page for a specific widget class.

You’ll also find that many Tkinter methods have compound names, e.g., winfo_x(), winfo_height(), winfo_viewable(). You’d find documentation for all of these in the winfo [https://www.tcl.tk/man/tcl8.6/TkCmd/winfo.htm] man page.

참고

Somewhat confusingly, there are also methods on all Tkinter widgets that don’t actually operate on the widget, but operate at a global scope, independent of any widget. Examples are methods for accessing the clipboard or the system bell. (They happen to be implemented as methods in the base Widget class that all Tkinter widgets inherit from).

Threading model

Python and Tcl/Tk have very different threading models, which tkinter tries to bridge. If you use threads, you may need to be aware of this.

A Python interpreter may have many threads associated with it. In Tcl, multiple threads can be created, but each thread has a separate Tcl interpreter instance associated with it. Threads can also create more than one interpreter instance, though each interpreter instance can be used only by the one thread that created it.

Each Tk object created by tkinter contains a Tcl interpreter. It also keeps track of which thread created that interpreter. Calls to tkinter can be made from any Python thread. Internally, if a call comes from a thread other than the one that created the Tk object, an event is posted to the interpreter’s event queue, and when executed, the result is returned to the calling Python thread.

Tcl/Tk applications are normally event-driven, meaning that after initialization, the interpreter runs an event loop (i.e. Tk.mainloop()) and responds to events. Because it is single-threaded, event handlers must respond quickly, otherwise they will block other events from being processed. To avoid this, any long-running computations should not run in an event handler, but are either broken into smaller pieces using timers, or run in another thread. This is different from many GUI toolkits where the GUI runs in a completely separate thread from all application code including event handlers.

If the Tcl interpreter is not running the event loop and processing events, any tkinter calls made from threads other than the one running the Tcl interpreter will fail.

A number of special cases exist:

Tcl/Tk libraries can be built so they are not thread-aware. In this case, tkinter calls the library from the originating Python thread, even if this is different than the thread that created the Tcl interpreter. A global lock ensures only one call occurs at a time.

While tkinter allows you to create more than one instance of a Tk object (with its own interpreter), all interpreters that are part of the same thread share a common event queue, which gets ugly fast. In practice, don’t create more than one instance of Tk at a time. Otherwise, it’s best to create them in separate threads and ensure you’re running a thread-aware Tcl/Tk build.

Blocking event handlers are not the only way to prevent the Tcl interpreter from reentering the event loop. It is even possible to run multiple nested event loops or abandon the event loop entirely. If you’re doing anything tricky when it comes to events or threads, be aware of these possibilities.

There are a few select tkinter functions that presently work only when called from the thread that created the Tcl interpreter.

간편한 레퍼런스

옵션 설정

옵션은 위젯의 색상과 테두리 너비와 같은 것을 제어합니다. 옵션은 세 가지 방법으로 설정할 수 있습니다:

객체 생성 시, 키워드 인자 사용하기

fred = Button(self, fg="red", bg="blue")

객체 생성 후, 딕셔너리 인덱스처럼 옵션 이름을 다루기

fred["fg"] = "red"
fred["bg"] = "blue"

config() 메서드를 사용하여 객체 생성 이후 여러 어트리뷰트를 갱신하기.

fred.config(fg="red", bg="blue")

주어진 옵션과 그 동작에 대한 완전한 설명은, 해당 위젯의 Tk 매뉴얼 페이지를 참조하십시오.

매뉴얼 페이지는 각 위젯에 대해 “표준 옵션(STANDARD OPTIONS)”과 “위젯 특정 옵션(WIDGET SPECIFIC OPTIONS)”을 나열합니다. 전자는 많은 위젯에 공통적인 옵션 목록이며, 후자는 그 위젯에만 적용되는 옵션입니다. 표준 옵션은 options(3) [https://manpages.debian.org/options(3)] 매뉴얼 페이지에 설명되어 있습니다.

이 문서에서는 표준과 위젯 특정 옵션을 구분하지 않습니다. 일부 옵션은 일부 위젯에 적용되지 않습니다. 특정 위젯이 특정 옵션에 응답하는지는 위젯의 클래스에 따라 다릅니다; 버튼에는 command 옵션이 있는데, 레이블은 그렇지 않습니다.

주어진 위젯이 지원하는 옵션은 위젯의 매뉴얼 페이지에 나열되거나, 실행 시간에 인자 없이 config() 메서드를 호출하거나 해당 위젯에서 keys() 메서드를 호출하여 조회할 수 있습니다. 이러한 호출의 반환 값은 키가 옵션의 이름인 문자열(예를 들어, 'relief')이고 값이 5-튜플인 딕셔너리입니다.

bg와 같은 일부 옵션은 긴 이름을 가진 공통 옵션의 동의어입니다 (bg는 “background”의 줄임말입니다). config() 메서드에 줄인 옵션을 전달하면 5-튜플이 아닌 2-튜플을 반환합니다. 전달된 2-튜플에는 동의어의 이름과 “실제” 옵션이 담겨있습니다 (가령 ('bg', 'background')).

인덱스

의미

예

0

옵션 이름

'relief'

1

데이터베이스 조회를 위한 옵션 이름

'relief'

2

데이터베이스 조회를 위한 옵션 클래스

'Relief'

3

기본값

'raised'

4

현재 값

'groove'

예:

>>> print(fred.config())
{'relief': ('relief', 'relief', 'Relief', 'raised', 'groove')}

물론, 인쇄된 딕셔너리에는 사용 가능한 모든 옵션과 해당 값이 포함됩니다. 이것은 예시일뿐입니다.

패커

패커(packer)는 Tk의 지오메트리 관리 메커니즘 중 하나입니다. 지오메트리 관리자는 컨테이너(위젯들의 공동 master) 내에서의 위젯의 상대 위치를 지정하는 데 사용됩니다. 더 성가신 placer(잘 사용되지 않고, 여기서는 다루지 않습니다) 와는 달리, 패커는 위에, 왼쪽에, 채우기 등의 정성적(qualitative) 관계 규정을 취하고, 여러분을 위해 정확한 배치 좌표를 결정하기 위한 모든 작업을 수행합니다.

모든 master 위젯의 크기는 안에 있는 “슬레이브(slave) 위젯”의 크기에 의해 결정됩니다. 패커는 슬레이브 위젯이 패킹 되는 마스터 내부에 나타나는 위치를 제어하는 데 사용됩니다. 원하는 배치를 얻기 위해 프레임에 위젯을 팩하고, 프레임을 다른 프레임에 팩할 수 있습니다. 또한, 일단 팩 되면, 점진적인 구성의 변경을 수용하기 위해 배치가 동적으로 조정됩니다.

위젯은 지오메트리 관리자로 지오메트리를 지정할 때까지 표시되지 않습니다. 지오메트리 명세를 빠뜨리는 것은 초기에 흔한 실수이고, 위젯을 만들었지만, 아무것도 나타나지 않을 때 놀라게 됩니다. 위젯은 예를 들어 패커의 pack() 메서드가 적용된 후에만 나타납니다.

pack() 메서드는 컨테이너 내에서 위젯이 표시되는 위치와 메인 응용 프로그램 윈도우의 크기가 조정될 때 어떻게 동작할지를 제어하는 키워드 옵션/값 쌍으로 호출할 수 있습니다. 여기 몇 가지 예가 있습니다:

fred.pack()                     # defaults to side = "top"
fred.pack(side="left")
fred.pack(expand=1)

패커 옵션

패커와 그것이 받을 수 있는 옵션에 대한 더 자세한 정보는 매뉴얼 페이지와 John Ousterhout의 책의 183쪽을 참조하십시오.

anchor

앵커(anchor)형. 패커가 각 슬레이브를 컨테이너에 넣을 위치를 나타냅니다.

expand

불리언(boolean), 0 또는 1.

fill

유효한 값: 'x', 'y', 'both', 'none'.

ipadx와 ipady

거리(distance) - 슬레이브 위젯의 각 변의 내부 패딩을 지정합니다.

padx와 pady

거리(distance) - 슬레이브 위젯의 각 변의 외부 패딩을 지정합니다.

side

유효한 값: 'left', 'right', 'top', 'bottom'.

위젯 변수 결합하기

(텍스트 입력 위젯과 같은) 일부 위젯의 현재 값 설정은 특수 옵션을 사용하여 응용 프로그램 변수에 직접 연결할 수 있습니다. 이 옵션은 variable, textvariable, onvalue, offvalue 및 value입니다. 이 연결은 양방향으로 작동합니다: 어떤 이유로 든 변수가 변경되면, 연결된 위젯은 새 값을 반영하도록 갱신됩니다.

불행히도, tkinter의 현재 구현에서는 variable 또는 textvariable 옵션을 통해 임의의 파이썬 변수를 위젯으로 넘길 수 없습니다. 작동하는 유일한 종류의 변수는 tkinter에 정의된 Variable이라는 클래스에서 서브 클래싱되는 변수입니다.

이미 정의된 Variable의 유용한 서브 클래스가 많이 있습니다: StringVar, IntVar, DoubleVar 및 BooleanVar. 이러한 변수의 현재 값을 읽으려면 get() 메서드를 호출하고, 값을 바꾸려면 set() 메서드를 호출합니다. 이 프로토콜을 따르면, 여러분이 더는 개입하지 않더라도 위젯은 변수의 값을 항상 추적합니다.

예를 들면:

import tkinter as tk

class App(tk.Frame):
    def __init__(self, master):
        super().__init__(master)
        self.pack()

        self.entrythingy = tk.Entry()
        self.entrythingy.pack()

        # Create the application variable.
        self.contents = tk.StringVar()
        # Set it to some value.
        self.contents.set("this is a variable")
        # Tell the entry widget to watch this variable.
        self.entrythingy["textvariable"] = self.contents

        # Define a callback for when the user hits return.
        # It prints the current value of the variable.
        self.entrythingy.bind('<Key-Return>',
                             self.print_contents)

    def print_contents(self, event):
        print("Hi. The current entry content is:",
              self.contents.get())

root = tk.Tk()
myapp = App(root)
myapp.mainloop()

창 관리자

Tk에는, 창 관리자와 상호 작용하기 위한 유틸리티 명령인 wm이 있습니다. wm 명령 옵션을 사용하여 제목, 배치, 아이콘 비트맵 등과 같은 항목을 제어할 수 있습니다. tkinter에서, 이러한 명령은 Wm 클래스의 메서드로 구현되었습니다. 최상위 위젯은 Wm 클래스의 서브 클래스이므로, Wm 메서드를 직접 호출할 수 있습니다.

주어진 위젯을 포함하는 최상위 창을 가져오려면, 종종 위젯의 마스터를 참조하는 것만으로도 됩니다. 물론 위젯이 프레임 안에 팩 되어 있다면, 마스터는 최상위 창을 나타내지 않을 것입니다. 임의의 위젯이 포함된 최상위 창을 가져오려면, _root() 메서드를 호출하면 됩니다. 이 메서드는 이 함수가 구현 일부이며, Tk 기능에 대한 인터페이스가 아니라는 사실을 나타내기 위해 밑줄로 시작합니다.

다음은 일반적인 사용 예입니다:

import tkinter as tk

class App(tk.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.pack()

# create the application
myapp = App()

#
# here are method calls to the window manager class
#
myapp.master.title("My Do-Nothing Application")
myapp.master.maxsize(1000, 400)

# start the program
myapp.mainloop()

Tk 옵션 데이터형

anchor

유효한 값은 나침반의 눈금입니다: "n", "ne", "e", "se", "s", "sw", "w", "nw", 그리고 "center".

bitmap

8개의 내장된, 이름있는 비트맵이 있습니다: 'error', 'gray25', 'gray50', 'hourglass', 'info', 'questhead', 'question', 'warning'. X 비트맵 파일명을 지정하려면 "@/usr/contrib/bitmap/gumby.bit"처럼 @를 앞에 붙인 파일의 전체 경로를 지정하십시오.

boolean

정수 0이나 1 또는 문자열 "yes"나 "no"를 전달할 수 있습니다.

callback

인자를 취하지 않는 파이썬 함수입니다. 예를 들면:

def print_it():
    print("hi there")
fred["command"] = print_it

color

Colors can be given as the names of X colors in the rgb.txt file, or as strings representing RGB values in 4 bit: "#RGB", 8 bit: "#RRGGBB", 12 bit: "#RRRGGGBBB", or 16 bit: "#RRRRGGGGBBBB" ranges, where R,G,B here represent any legal hex digit. See page 160 of Ousterhout’s book for details.

cursor

XC_ 접두사 없이 cursorfont.h의 표준 X 커서 이름을 사용할 수 있습니다. 예를 들어, 손 모양 커서(XC_hand2)를 얻으려면, "hand2" 문자열을 사용하십시오. 여러분 자신의 비트맵과 마스크 파일을 지정할 수도 있습니다. Ousterhout의 책 179쪽을 보십시오.

distance

화면 거리는 픽셀이나 절대 거리로 지정할 수 있습니다. 픽셀은 숫자로 절대 거리는 문자열로 지정되며, 끝에 붙는 문자는 단위를 나타냅니다: c는 센티미터, i는 인치, m은 밀리미터, p는 프린터의 포인트입니다. 예를 들어, 3.5 인치는 "3.5i"로 표현됩니다.

font

Tk는 {courier 10 bold}와 같은, 목록 글꼴 이름 형식을 사용합니다. 양수로 표현된 글꼴 크기는 포인트로 측정됩니다; 음수로 표현된 크기는 픽셀 단위로 측정됩니다.

geometry

이것은 너비x높이 형식의 문자열로, 대부분의 위젯에서 너비와 높이는 픽셀 단위로 측정됩니다 (텍스트를 표시하는 위젯에서는 문자 단위). 예를 들어: fred["geometry"] = "200x100".

justify

유효한 값은 문자열입니다: "left", "center", "right" 및 "fill".

region

이것은 스페이스로 구분된 네 개의 요소가 있는 문자열이며, 각 요소는 유효한 거리(위를 참조하세요)입니다. 예를 들어: "2 3 4 5"와 "3i 2i 4.5i 2i"와 "3c 2c 4c 10.43c"는 모두 유효한 영역(region)입니다.

relief

위젯의 테두리 스타일을 결정합니다. 유효한 값은 다음과 같습니다: "raised", "sunken", "flat", "groove" 및 "ridge".

scrollcommand

이것은 거의 항상 어떤 스크롤 막대 위젯의 set() 메서드이지만, 단일 인자를 취하는 어떤 위젯 메서드도 가능합니다.

wrap

"none", "char" 또는 "word" 중 하나여야 합니다.

바인딩과 이벤트

위젯 명령의 bind 메서드를 사용하면 특정 이벤트를 감시하고 해당 이벤트 유형이 발생할 때 콜백 함수가 트리거 되도록 할 수 있습니다. bind 메서드의 형식은 다음과 같습니다:

def bind(self, sequence, func, add=''):

여기에서:

sequence

is a string that denotes the target kind of event. (See the bind(3tk) [https://manpages.debian.org/bind(3tk)] man page, and page 201 of John Ousterhout’s book, Tcl and the Tk Toolkit (2nd edition), for details).

func

는 하나의 인자를 취하는 파이썬 함수로, 이벤트가 발생할 때 호출됩니다. 이벤트 인스턴스가 인자로 전달됩니다. (이런 식으로 설치되는 함수를 흔히 콜백(callbacks)이라고 합니다.)

add

는 선택적이고, ''나 '+'입니다. 빈 문자열을 전달하면 이 바인딩이 이 이벤트와 연관된 다른 바인딩을 대체 함을 나타냅니다. '+'를 전달하면 이 함수가 이 이벤트 유형에 바인딩 된 함수 목록에 추가됩니다.

예를 들면:

def turn_red(self, event):
    event.widget["activeforeground"] = "red"

self.button.bind("<Enter>", self.turn_red)

이벤트의 widget 필드가 turn_red() 콜백에서 어떻게 액세스 되는지 주목하십시오. 이 필드는 X 이벤트를 포착한 위젯을 포함합니다. 다음 표에는 사용자가 액세스할 수 있는 다른 이벤트 필드와 Tk에서 이들을 표시하는 방법이 나열되어 있습니다. Tk 매뉴얼 페이지를 참조할 때 유용할 수 있습니다.

Tk

Tkinter 이벤트 필드

Tk

Tkinter 이벤트 필드

%f

focus

%A

char

%h

height

%E

send_event

%k

keycode

%K

keysym

%s

state

%N

keysym_num

%t

time

%T

type

%w

width

%W

widget

%x

x

%X

x_root

%y

y

%Y

y_root

index 매개 변수

많은 위젯에는 “index” 매개 변수가 전달되어야 합니다. 이들은 Text 위젯의 특정 위치, Entry 위젯의 특정 문자 또는 Menu 위젯의 특정 메뉴 항목을 가리키는 데 사용됩니다.

Entry 위젯 인덱스 (인덱스, 뷰 인덱스 등)

Entry 위젯에는 표시되는 텍스트의 문자 위치를 참조하는 옵션이 있습니다. 다음 tkinter 함수를 사용하여 텍스트 위젯에서 이러한 특수 지점에 액세스할 수 있습니다:

Text 위젯 인덱스

Text 위젯의 인덱스 표기법은 매우 풍부하며 Tk 매뉴얼 페이지에 자세히 설명되어 있습니다.

메뉴 인덱스 (menu.invoke(), menu.entryconfig() 등)

메뉴에 대한 일부 옵션 및 메서드는 특정 메뉴 항목을 조작합니다. 옵션이나 매개 변수에 메뉴 인덱스가 필요한 때는 언제든지 다음과 같이 전달할 수 있습니다:

위에서부터 세고, 0에서 시작하는, 위젯에서 항목의 숫자 위치를 나타내는 정수.

현재 커서 아래에 있는 메뉴 위치를 나타내는, 문자열 "active".

마지막 메뉴 항목을 나타내는, 문자열 "last".

@6과 같이, @이 앞에 오는 정수로, 정수는 메뉴의 좌표계에서 y 픽셀 좌표로 해석됩니다.

아무런 메뉴 항목을 가리키지 않는, 문자열 "none"은 menu.activate()와 함께 사용되어 모든 항목을 비활성화합니다, 마지막으로,

메뉴 맨 위에서 아래로 스캔할 때, 메뉴 항목의 레이블과 패턴 일치하는 텍스트 문자열. 이 인덱스 유형은 다른 모든 항목 다음에 고려되므로, last, active 또는 none 레이블이 붙은 메뉴 항목과의 일치가 대신 위의 리터럴로 해석될 수 있음을 의미합니다.

이미지

서로 다른 형식의 이미지를 tkinter.Image의 해당 서브 클래스를 통해 만들 수 있습니다:

XBM 형식의 이미지를 위한 BitmapImage.

PGM, PPM, GIF 및 PNG 형식의 이미지를 위한 PhotoImage. 후자는 Tk 8.6부터 지원됩니다.

두 가지 유형의 이미지는 file 또는 data 옵션을 통해 만들어집니다 (다른 옵션도 사용할 수 있습니다).

버전 3.13에서 변경: Added the PhotoImage method copy_replace() to copy a region from one image to other image, possibly with pixel zooming and/or subsampling. Add from_coords parameter to PhotoImage methods copy(), zoom() and subsample(). Add zoom and subsample parameters to PhotoImage method copy().

그런 다음 image 옵션이 일부 위젯(예를 들어, 레이블, 버튼, 메뉴)에서 지원되는 곳이면 어디든 이미지 객체를 사용할 수 있습니다. 이 경우, Tk는 이미지에 대한 참조를 유지하지 않습니다. 이미지 객체에 대한 마지막 파이썬 참조가 삭제되면 이미지 데이터도 삭제되고, Tk는 이미지가 사용된 곳마다 빈 상자를 표시합니다.

더 보기

The Pillow [https://python-pillow.org/] package adds support for formats such as BMP, JPEG, TIFF, and WebP, among others.

파일 처리기

Tk는 파일 기술자에서 I/O가 가능할 때 Tk 메인 루프에서 호출할 콜백 함수를 등록하고 등록 취소할 수 있도록 합니다. 파일 기술자당 하나의 처리기 만 등록 될 수 있습니다. 예제 코드:

import tkinter
widget = tkinter.Tk()
mask = tkinter.READABLE | tkinter.WRITABLE
widget.tk.createfilehandler(file, mask, callback)
...
widget.tk.deletefilehandler(file)

윈도우에서는 이 기능을 사용할 수 없습니다.

얼마나 많은 바이트를 읽을 수 있는지 모르므로, BufferedIOBase나 TextIOBase read()나 readline() 메서드를 사용하고 싶지 않을것입니다, 이것들은 미리 정의 된 바이트 수를 읽으려고하기 때문입니다. 소켓의 경우, recv() 또는 recvfrom() 메서드가 제대로 작동합니다; 다른 파일의 경우, 날(raw) 읽기나 os.read(file.fileno(), maxbytecount)를 사용하십시오.

Widget.tk.createfilehandler(file, mask, func)

파일 처리기 콜백 함수 func를 등록합니다. file 인자는 fileno() 메서드가 있는 객체이거나(가령 파일이나 소켓 객체), 정수 파일 기술자일 수 있습니다. mask 인자는 아래의 세 가지 상수들을 OR로 조합한 것입니다. 콜백은 다음과 같이 호출됩니다:

callback(file, mask)

Widget.tk.deletefilehandler(file)

파일 처리기를 등록 취소합니다.

_tkinter.READABLE

_tkinter.WRITABLE

_tkinter.EXCEPTION

mask 인자에 사용되는 상수입니다.

tkinter.colorchooser — Color choosing dialog

소스 코드: Lib/tkinter/colorchooser.py [https://github.com/python/cpython/tree/main/Lib/tkinter/colorchooser.py]

tkinter.colorchooser 모듈은 네이티브 색상 선택기 대화 상자의 인터페이스로 Chooser 클래스를 제공합니다. Chooser는 모달(modal) 색상 선택 대화 상자 창을 구현합니다. Chooser 클래스는 Dialog 클래스를 상속합니다.

class tkinter.colorchooser.Chooser(master=None, **options)

tkinter.colorchooser.askcolor(color=None, **options)

색상 선택 대화 상자를 만듭니다. 이 메서드를 호출하면 창이 표시되고, 사용자가 선택하기를 기다렸다가, 선택한 색상(또는 None)을 호출자에게 반환합니다.

더 보기

모듈 tkinter.commondialog

Tkinter 표준 대화 상자 모듈

tkinter.font — Tkinter font wrapper

소스 코드: Lib/tkinter/font.py [https://github.com/python/cpython/tree/main/Lib/tkinter/font.py]

tkinter.font 모듈은 명명된 글꼴을 만들고 사용하기 위한 Font 클래스를 제공합니다.

구별되는 글꼴 무게와 기울기는 다음과 같습니다:

tkinter.font.NORMAL

tkinter.font.BOLD

tkinter.font.ITALIC

tkinter.font.ROMAN

class tkinter.font.Font(root=None, font=None, name=None, exists=False, **options)

Font 클래스는 명명된 글꼴을 나타냅니다. Font 인스턴스에는 고유한 이름이 지정되며 패밀리, 크기 및 스타일 구성으로 지정할 수 있습니다. 명명된 글꼴은 나타날 때마다 어트리뷰트로 글꼴을 지정하지 않고, 글꼴을 단일 객체로 만들고 식별하는 Tk의 방법입니다.

인자:

font - 글꼴 지정자 튜플 (패밀리, 크기, 옵션)

name - 고유한 글꼴 이름

exists - 참이면 self가 기존의 명명된 글꼴을 가리킵니다

추가 키워드 옵션 (font가 지정되면 무시됩니다):

family - 글꼴 패밀리, 즉 Courier, Times

size - 글꼴 크기

size가 양수이면 포인트 단위의 크기로 해석됩니다.

size가 음수이면 절댓값을

픽셀 단위의 크기로 처리합니다.

weight - 글꼴 강조 (NORMAL, BOLD)

slant - ROMAN, ITALIC

underline - 글꼴 밑줄 (0 - 없음, 1 - 밑줄)

overstrike - 글꼴 취소선 (0 - 없음, 1 - 취소선)

actual(option=None, displayof=None)

글꼴의 어트리뷰트를 반환합니다.

cget(option)

글꼴의 어트리뷰트를 가져옵니다.

config(**options)

글꼴의 어트리뷰트를 수정합니다.

copy()

현재 글꼴의 새 인스턴스를 반환합니다.

measure(text, displayof=None)

현재 글꼴로 포맷할 때 지정된 디스플레이에서 텍스트가 차지할 공간의 크기를 반환합니다. 디스플레이가 지정되지 않으면 메인 응용 프로그램 창을 가정합니다.

metrics(*options, **kw)

글꼴별 데이터를 반환합니다. 옵션은 다음과 같습니다:

ascent - 기준선(baseline)과 글꼴의 문자가 차지할 수 있는 가장 높은 점 사이의 거리

.

descent - 기준선과 글꼴의 문자가 차지할 수 있는 가장 낮은 점 사이의 거리

.

linespace - 줄 사이에 수직 겹침이 없음을 보장하는, 글꼴의 임의의 두 문자 간에 필요한 최소 수직 분리

.

fixed - 글꼴이 고정 너비이면 1, 그렇지 않으면 0

tkinter.font.families(root=None, displayof=None)

구별되는 글꼴 패밀리를 반환합니다.

tkinter.font.names(root=None)

정의된 글꼴의 이름을 반환합니다.

tkinter.font.nametofont(name, root=None)

tk 명명된 글꼴의 Font 표현을 반환합니다.

버전 3.10에서 변경: The root parameter was added.

Tkinter 대화 상자

tkinter.simpledialog — 표준 Tkinter 입력 대화 상자

소스 코드: Lib/tkinter/simpledialog.py [https://github.com/python/cpython/tree/main/Lib/tkinter/simpledialog.py]

tkinter.simpledialog 모듈에는 사용자로부터 값을 얻기 위한 간단한 모달 대화 상자를 만드는 편의 클래스와 함수가 포함되어 있습니다.

tkinter.simpledialog.askfloat(title, prompt, **kw)

tkinter.simpledialog.askinteger(title, prompt, **kw)

tkinter.simpledialog.askstring(title, prompt, **kw)

위의 세 함수는 사용자에게 원하는 형의 값을 입력하도록 요구하는 대화 상자를 제공합니다.

class tkinter.simpledialog.Dialog(parent, title=None)

사용자 정의 대화 상자의 베이스 클래스.

body(master)

대화 상자의 인터페이스를 구성하고 초기 포커스가 필요한 위젯을 반환하도록 재정의하십시오.

buttonbox()

기본 동작은 OK 와 Cancel 버튼을 추가합니다. 사용자 정의 버튼 레이아웃이 필요하면 재정의하십시오.

tkinter.filedialog — 파일 선택 대화 상자

소스 코드: Lib/tkinter/filedialog.py [https://github.com/python/cpython/tree/main/Lib/tkinter/filedialog.py]

tkinter.filedialog 모듈은 파일/디렉터리 선택 창을 만들기위한 클래스와 팩토리 함수를 제공합니다.

네이티브 로드/저장 대화 상자

다음 클래스와 함수는 네이티브 모양과 느낌을 동작을 사용자 정의하는 구성 옵션과 결합하는 파일 대화 상자 창을 제공합니다. 다음 키워드 인자는 아래 나열된 클래스와 함수에 적용할 수 있습니다:

parent - 대화 상자를 그 위에 놓을 창

title - 창의 제목

initialdir - 대화 상자가 시작되는 디렉터리

initialfile - 대화 상자를 열 때 선택된 파일

filetypes - (label, pattern) 튜플의 시퀀스, ‘*’ 와일드카드가 허용됩니다

defaultextension - 파일에 추가할 기본 확장자 (저장 대화 상자)

multiple - 참일 때, 여러 항목을 선택할 수 있습니다

정적 팩토리 함수

아래 함수는 호출될 때 모달, 네이티브 모양과 느낌의 대화 상자를 만들고, 사용자의 선택을 기다린 다음, 선택한 값이나 None을 호출자에게 반환합니다.

tkinter.filedialog.askopenfile(mode='r', **options)

tkinter.filedialog.askopenfiles(mode='r', **options)

위의 두 함수는 Open 대화 상자를 만들고 열린 파일 객체를 읽기 전용 모드로 반환합니다.

tkinter.filedialog.asksaveasfile(mode='w', **options)

SaveAs 대화 상자를 만들고 쓰기 전용 모드로 열린 파일 객체를 반환합니다.

tkinter.filedialog.askopenfilename(**options)

tkinter.filedialog.askopenfilenames(**options)

위의 두 함수는 Open 대화 상자를 만들고 기존 파일(들)에 해당하는 선택된 파일명(들)을 반환합니다.

tkinter.filedialog.asksaveasfilename(**options)

SaveAs 대화 상자를 만들고 선택한 파일명을 반환합니다.

tkinter.filedialog.askdirectory(**options)

사용자에게 디렉터리를 선택하라는 메시지를 표시합니다.

추가 키워드 옵션:

mustexist - 선택이 기존 디렉터리여야 하는지를 결정합니다.

class tkinter.filedialog.Open(master=None, **options)

class tkinter.filedialog.SaveAs(master=None, **options)

위의 두 클래스는 파일 저장과 로드를 위한 네이티브 대화 창을 제공합니다.

편의 클래스

아래 클래스는 파일/디렉터리 창을 처음부터 만드는 데 사용됩니다. 이것들은 플랫폼의 네이티브 모양과 느낌을 모방하지 않습니다.

class tkinter.filedialog.Directory(master=None, **options)

사용자에게 디렉터리를 선택하라는 대화 상자를 만듭니다.

참고

FileDialog 클래스는 사용자 정의 이벤트 처리와 동작을 위해 서브 클래싱 되어야 합니다.

class tkinter.filedialog.FileDialog(master, title=None)

기본 파일 선택 대화 상자를 만듭니다.

cancel_command(event=None)

대화 창의 종료를 트리거 합니다.

dirs_double_event(event)

디렉터리에 대한 더블 클릭 이벤트를 위한 이벤트 처리기.

dirs_select_event(event)

디렉터리에 대한 클릭 이벤트를 위한 이벤트 처리기.

files_double_event(event)

파일에 대한 더블 클릭 이벤트를 위한 이벤트 처리기.

files_select_event(event)

파일에 대한 단일 클릭 이벤트를 위한 이벤트 처리기.

filter_command(event=None)

디렉터리로 파일을 필터링합니다.

get_filter()

현재 사용 중인 파일 필터를 가져옵니다.

get_selection()

현재 선택된 항목을 가져옵니다.

go(dir_or_file=os.curdir, pattern='*', default='', key=None)

대화 상자를 렌더링하고 이벤트 루프를 시작합니다.

ok_event(event)

현재 선택을 반환하면서 대화 상자를 종료합니다.

quit(how=None)

파일명을 (있다면) 반환하면서 대화 상자를 종료합니다.

set_filter(dir, pat)

파일 필터를 설정합니다.

set_selection(file)

현재 파일 선택을 file로 갱신합니다.

class tkinter.filedialog.LoadFileDialog(master, title=None)

기존 파일을 선택하기 위한 대화 상자 창을 만드는 FileDialog의 서브 클래스.

ok_command()

파일이 제공되고 선택이 이미 존재하는 파일을 가리키는지 테스트합니다.

class tkinter.filedialog.SaveFileDialog(master, title=None)

대상 파일을 선택하기 위한 대화 상자 창을 만드는 FileDialog의 서브 클래스.

ok_command()

선택이 디렉터리가 아닌 유효한 파일을 가리키는지 테스트합니다. 이미 존재하는 파일을 선택했으면 확인이 필요합니다.

tkinter.commondialog — 대화창 템플릿

소스 코드: Lib/tkinter/commondialog.py [https://github.com/python/cpython/tree/main/Lib/tkinter/commondialog.py]

tkinter.commondialog 모듈은 다른 지원 모듈에 정의된 대화 상자의 베이스 클래스인 Dialog 클래스를 제공합니다.

class tkinter.commondialog.Dialog(master=None, **options)

show(color=None, **options)

대화창을 렌더링합니다.

더 보기

모듈 tkinter.messagebox, 파일을 읽고 쓰기

tkinter.messagebox — Tkinter message prompts

소스 코드: Lib/tkinter/messagebox.py [https://github.com/python/cpython/tree/main/Lib/tkinter/messagebox.py]

The tkinter.messagebox module provides a template base class as well as a variety of convenience methods for commonly used configurations. The message boxes are modal and will return a subset of (True, False, None, OK, CANCEL, YES, NO) based on the user’s selection. Common message box styles and layouts include but are not limited to:

class tkinter.messagebox.Message(master=None, **options)

Create a message window with an application-specified message, an icon and a set of buttons. Each of the buttons in the message window is identified by a unique symbolic name (see the type options).

The following options are supported:

command

Specifies the function to invoke when the user closes the dialog. The name of the button clicked by the user to close the dialog is passed as argument. This is only available on macOS.

default

Gives the symbolic name of the default button for this message window (OK, CANCEL, and so on). If this option is not specified, the first button in the dialog will be made the default.

detail

Specifies an auxiliary message to the main message given by the message option. The message detail will be presented beneath the main message and, where supported by the OS, in a less emphasized font than the main message.

icon

Specifies an icon to display. If this option is not specified, then the INFO icon will be displayed.

message

Specifies the message to display in this message box. The default value is an empty string.

parent

Makes the specified window the logical parent of the message box. The message box is displayed on top of its parent window.

title

Specifies a string to display as the title of the message box. This option is ignored on macOS, where platform guidelines forbid the use of a title on this kind of dialog.

type

Arranges for a predefined set of buttons to be displayed.

show(**options)

Display a message window and wait for the user to select one of the buttons. Then return the symbolic name of the selected button. Keyword arguments can override options specified in the constructor.

정보 메시지 상자

tkinter.messagebox.showinfo(title=None, message=None, **options)

Creates and displays an information message box with the specified title and message.

경고 메시지 상자

tkinter.messagebox.showwarning(title=None, message=None, **options)

Creates and displays a warning message box with the specified title and message.

tkinter.messagebox.showerror(title=None, message=None, **options)

Creates and displays an error message box with the specified title and message.

질문 메시지 상자

tkinter.messagebox.askquestion(title=None, message=None, *, type=YESNO, **options)

Ask a question. By default shows buttons YES and NO. Returns the symbolic name of the selected button.

tkinter.messagebox.askokcancel(title=None, message=None, **options)

Ask if operation should proceed. Shows buttons OK and CANCEL. Returns True if the answer is ok and False otherwise.

tkinter.messagebox.askretrycancel(title=None, message=None, **options)

Ask if operation should be retried. Shows buttons RETRY and CANCEL. Return True if the answer is yes and False otherwise.

tkinter.messagebox.askyesno(title=None, message=None, **options)

Ask a question. Shows buttons YES and NO. Returns True if the answer is yes and False otherwise.

tkinter.messagebox.askyesnocancel(title=None, message=None, **options)

Ask a question. Shows buttons YES, NO and CANCEL. Return True if the answer is yes, None if cancelled, and False otherwise.

Symbolic names of buttons:

tkinter.messagebox.ABORT = 'abort'

tkinter.messagebox.RETRY = 'retry'

tkinter.messagebox.IGNORE = 'ignore'

tkinter.messagebox.OK = 'ok'

tkinter.messagebox.CANCEL = 'cancel'

tkinter.messagebox.YES = 'yes'

tkinter.messagebox.NO = 'no'

Predefined sets of buttons:

tkinter.messagebox.ABORTRETRYIGNORE = 'abortretryignore'

Displays three buttons whose symbolic names are ABORT, RETRY and IGNORE.

tkinter.messagebox.OK = 'ok'

Displays one button whose symbolic name is OK.

tkinter.messagebox.OKCANCEL = 'okcancel'

Displays two buttons whose symbolic names are OK and CANCEL.

tkinter.messagebox.RETRYCANCEL = 'retrycancel'

Displays two buttons whose symbolic names are RETRY and CANCEL.

tkinter.messagebox.YESNO = 'yesno'

Displays two buttons whose symbolic names are YES and NO.

tkinter.messagebox.YESNOCANCEL = 'yesnocancel'

Displays three buttons whose symbolic names are YES, NO and CANCEL.

Icon images:

tkinter.messagebox.ERROR = 'error'

tkinter.messagebox.INFO = 'info'

tkinter.messagebox.QUESTION = 'question'

tkinter.messagebox.WARNING = 'warning'

tkinter.scrolledtext — Scrolled Text Widget

소스 코드: Lib/tkinter/scrolledtext.py [https://github.com/python/cpython/tree/main/Lib/tkinter/scrolledtext.py]

tkinter.scrolledtext 모듈은 “올바로” 동작하도록 구성된 수직 스크롤 막대가 있는 기본 텍스트 위젯을 구현하는 같은 이름의 클래스를 제공합니다. ScrolledText 클래스를 사용하면 텍스트 위젯과 스크롤 막대를 직접 설정하기보다 훨씬 쉽습니다.

텍스트 위젯과 스크롤 막대는 Frame에 함께 팩 되며, Grid와 Pack 지오메트리 관리자의 메서드를 Frame 객체에서 얻습니다. 이렇게 함으로써, 가장 일반적인 지오메트리 관리 동작을 달성하는데 ScrolledText 위젯을 직접 사용할 수 있습니다.

더욱 구체적인 제어가 필요하면, 다음 어트리뷰트를 사용할 수 있습니다:

class tkinter.scrolledtext.ScrolledText(master=None, **kw)

frame

텍스트 및 스크롤 막대 위젯을 둘러싼 프레임.

vbar

스크롤 막대 위젯.

tkinter.dnd — Drag and drop support

소스 코드: Lib/tkinter/dnd.py [https://github.com/python/cpython/tree/main/Lib/tkinter/dnd.py]

참고

이것은 실험적이며 Tk DND로 대체될 때 폐지될 예정입니다.

tkinter.dnd 모듈은 단일 응용 프로그램 내에서, 같은 창 내에서 또는 창 간에 객체에 대해 드래그 앤드 드롭(끌어서 놓기) 지원을 제공합니다. 객체를 드래그할 수 있게 하려면, 드래그 앤드 드롭 프로세스를 시작하는 이벤트 바인딩을 만들어야 합니다. 일반적으로, ButtonPress 이벤트를 여러분이 작성한 콜백 함수에 바인딩합니다 (바인딩과 이벤트를 참조하십시오). 이 함수는 dnd_start()를 호출해야 합니다, 여기서 ‘source’는 드래그할 객체이고, ‘event’는 호출을 일으킨 이벤트입니다 (콜백 함수의 인자입니다).

대상 객체는 다음과 같이 선택됩니다:

대상 위젯에 대한 마우스 아래 영역의 하향식 검색

대상 위젯에는 콜러블 dnd_accept 어트리뷰트가 있어야 합니다

If dnd_accept is not present or returns None, search moves to parent widget

If no target widget is found, then the target object is None

<old_target>.dnd_leave(source, event)를 호출합니다

<new_target>.dnd_enter(source, event)를 호출합니다

드롭을 알리기 위해 <target>.dnd_commit(source, event)를 호출합니다

드래그 앤드 드롭의 끝을 알리기 위해 <source>.dnd_end(target, event)를 호출합니다

class tkinter.dnd.DndHandler(source, event)

DndHandler 클래스는 이벤트 위젯의 루트에서 Motion과 ButtonRelease 이벤트를 추적하는 드래그 앤드 드롭 이벤트를 처리합니다.

cancel(event=None)

드래그 앤드 드롭 프로세스를 취소합니다.

finish(event, commit=0)

드래그 앤드 드롭 기능의 끝을 실행합니다.

on_motion(event)

드래그가 수행되는 동안 마우스 아래의 대상 객체를 검사합니다.

on_release(event)

릴리즈 패턴이 트리거 될 때 드래그의 끝을 알립니다.

tkinter.dnd.dnd_start(source, event)

드래그 앤드 드롭 프로세스를 위한 팩토리 함수.

더 보기

바인딩과 이벤트

tkinter.ttk — Tk themed widgets

소스 코드: Lib/tkinter/ttk.py [https://github.com/python/cpython/tree/main/Lib/tkinter/ttk.py]

The tkinter.ttk module provides access to the Tk themed widget set, introduced in Tk 8.5. It provides additional benefits including anti-aliased font rendering under X11 and window transparency (requiring a composition window manager on X11).

tkinter.ttk의 기본 아이디어는 위젯 동작을 구현하는 코드와 모양을 구현하는 코드를 가능한 한 분리하는 것입니다.

더 보기

Tk 위젯 스타일링 지원 [https://core.tcl.tk/tips/doc/trunk/tip/48.md]

Tk의 테마 지원을 소개하는 문서

Ttk 사용하기

Ttk를 사용하려면, 모듈을 임포트 하십시오:

from tkinter import ttk

기본 Tk 위젯을 재정의하려면, 임포트는 Tk 임포트 뒤에 와야 합니다:

from tkinter import *
from tkinter.ttk import *

이 코드로 인해 여러 tkinter.ttk 위젯(Button, Checkbutton, Entry, Frame, Label, LabelFrame, Menubutton, PanedWindow, Radiobutton, Scale 및 Scrollbar)이 Tk 위젯을 자동으로 대체합니다.

이것은 여러 플랫폼에서 더 나은 모양과 느낌을 제공하는 새로운 위젯을 사용하는 직접적인 이점이 있지만, 대체된 위젯은 완전히 호환되지 않습니다. 주요 차이점은 “fg”, “bg” 및 위젯 스타일과 관련된 다른 위젯 옵션이 더는 Ttk 위젯에 존재하지 않는다는 것입니다. 대신, 스타일링 효과를 개선하려면 ttk.Style 클래스를 사용하십시오.

더 보기

Converting existing applications to use Tile widgets [https://tktable.sourceforge.net/tile/doc/converting.txt]

새 위젯을 사용하도록 응용 프로그램을 바꿀 때 일반적으로 발생하는 차이점에 대한 모노그래프 (Tcl 용어로).

Ttk 위젯

Ttk에는 18개의 위젯이 있으며, 그중 12개는 tkinter에 이미 존재합니다: Button, Checkbutton, Entry, Frame, Label, LabelFrame, Menubutton, PanedWindow, Radiobutton, Scale, Scrollbar 및 Spinbox. 다른 6개는 Combobox, Notebook, Progressbar, Separator, Sizegrip 및 Treeview입니다. 그리고 이들은 모두 Widget의 서브 클래스입니다.

Ttk 위젯을 사용하면 응용 프로그램의 모양과 느낌이 개선됩니다. 위에서 설명한 것처럼, 스타일을 코딩하는 방법에는 차이가 있습니다.

Tk 코드:

l1 = tkinter.Label(text="Test", fg="black", bg="white")
l2 = tkinter.Label(text="Test", fg="black", bg="white")

Ttk 코드:

style = ttk.Style()
style.configure("BW.TLabel", foreground="black", background="white")

l1 = ttk.Label(text="Test", style="BW.TLabel")
l2 = ttk.Label(text="Test", style="BW.TLabel")

Ttk 스타일링에 대한 자세한 정보는, Style 클래스 설명서를 참조하십시오.

Widget

ttk.Widget은 Tk 테마 위젯이 지원하는 표준 옵션과 메서드를 정의하며 직접 인스턴스 화하지 않습니다.

표준 옵션

All the ttk Widgets accept the following options:

옵션

설명

class

윈도우 클래스를 지정합니다. 이 클래스는 창의 다른 옵션에 대한 옵션 데이터베이스를 조회하고, 창의 기본 바인딩 태그를 결정하고, 위젯의 기본 레이아웃과 스타일을 선택하는 데 사용됩니다. 이 옵션은 읽기 전용이며, 창을 만들 때만 지정할 수 있습니다.

cursor

위젯에 사용될 마우스 커서를 지정합니다. 빈 문자열(기본값)로 설정하면, 커서가 부모 위젯에서 상속됩니다.

takefocus

키보드 순회 중 창에서 포커스를 받아들일지를 결정합니다. 0, 1 또는 빈 문자열이 반환됩니다. 0이 반환되면, 키보드 순회 중에 창을 완전히 건너뛰어야 한다는 의미입니다. 1이면, 창은 볼 수 있는 한 입력 포커스를 받아야 함을 의미합니다. 빈 문자열은 순회 스크립트가 창에 포커스를 맞출지를 결정함을 의미합니다.

style

사용자 정의 위젯 스타일을 지정하는 데 사용될 수 있습니다.

스크롤 가능한 위젯 옵션

다음 옵션은 스크롤 막대로 제어되는 위젯에서 지원됩니다.

옵션

설명

xscrollcommand

가로 스크롤 막대와 통신하는 데 사용됩니다.

위젯 창에 있는 뷰가 변경될 때, 위젯은 scrollcommand를 기반한 Tcl 명령을 생성합니다.

일반적으로 이 옵션은 어떤 스크롤 막대의 메서드 Scrollbar.set()으로 구성됩니다. 그러면 창의 뷰가 변경될 때마다 스크롤 막대가 갱신됩니다.

yscrollcommand

세로 스크롤 막대와 통신하는 데 사용됩니다. 자세한 내용은 위를 참조하십시오.

레이블 옵션

다음 옵션은 레이블, 버튼 및 기타 버튼류 위젯에서 지원됩니다.

옵션

설명

text

위젯 안에 표시할 텍스트 문자열을 지정합니다.

textvariable

text 옵션 자원 대신 그 값이 사용될 이름을 지정합니다.

underline

설정되면, 텍스트 문자열에서 밑줄 그을 문자의 인덱스(0에서 시작)를 지정합니다. 밑줄 있는 문자는 니모닉 활성화(mnemonic activation)에 사용됩니다.

image

표시할 이미지를 지정합니다. 이것은 하나 이상의 요소로 구성된 리스트입니다. 첫 번째 요소는 기본 이미지 이름입니다. 리스트의 나머지가 Style.map()에 의해 정의된 대로 statespec/value 쌍의 시퀀스면, 위젯이 특정 상태나 상태의 조합에 있을 때 사용할 다른 이미지를 지정합니다. 리스트의 모든 이미지는 크기가 같아야 합니다.

compound

텍스트와 이미지 옵션이 모두 있을 때, 텍스트를 기준으로 이미지를 표시하는 방법을 지정합니다. 유효한 값은 다음과 같습니다:

text: 텍스트만 표시합니다

image: 이미지만 표시합니다

top, bottom, left, right: 각각 이미지를 텍스트 위, 아래, 왼쪽 또는 오른쪽에 표시합니다.

none: 기본값입니다. 있으면 이미지를 표시하고, 그렇지 않으면 텍스트를 표시합니다.

width

0보다 크면, 문자 너비 단위로, 텍스트 레이블에 할당할 공간의 크기를 지정합니다, 0보다 작으면, 최소 너비를 지정합니다. 0으로 지정하거나 지정하지 않으면, 텍스트 레이블의 자연 너비가 사용됩니다.

호환성 옵션

옵션

설명

state

“disabled” 상태 비트를 제어하기 위해 “normal”이나 “disabled”로 설정될 수 있습니다. 이것은 쓰기 전용 옵션입니다: 이를 설정하면 위젯 상태가 변경되지만, Widget.state() 메서드는 이 옵션에 영향을 미치지 않습니다.

위젯 상태

위젯 상태는 독립 상태 플래그의 비트 맵입니다.

플래그

설명

active

마우스 커서가 위젯 위에 있으며 마우스 버튼을 누르면 어떤 동작을 일으킵니다

disabled

프로그램 제어 하에 위젯이 비활성화되었습니다

focus

위젯에 키보드 포커스가 있습니다

pressed

위젯을 누르고 있습니다

selected

체크 버튼과 라디오 버튼과 같은 항목의 경우 “On”, “true” 또는 “current”

background

윈도우와 맥에는 “활성(active)”이나 전경(foreground) 창이라는 개념이 있습니다. background 상태는 배경 창의 위젯에 대해 설정되고, 전경 창의 위젯에서는 지워집니다.

readonly

위젯이 사용자 수정을 허용하지 않습니다

alternate

위젯 별 대체 디스플레이 포맷

invalid

위젯 값이 유효하지 않습니다

상태 명세는 상태 이름의 시퀀스이며, 선택적으로 비트가 꺼져 있음을 나타내는 느낌표가 접두어로 붙습니다.

ttk.Widget

아래 설명된 메서드 외에도 ttk.Widget은 메서드 tkinter.Widget.cget()과 tkinter.Widget.configure()를 지원합니다.

class tkinter.ttk.Widget

identify(x, y)

위치 x y에 있는 요소의 이름을 반환하거나, 점이 요소 내에 없으면 빈 문자열을 반환합니다.

x 와 y는 위젯에 상대적인 픽셀 좌표입니다.

instate(statespec, callback=None, *args, **kw)

위젯 상태를 테스트합니다. 콜백을 지정하지 않으면, 위젯 상태가 statespec과 일치하면 True를, 그렇지 않으면 False를 반환합니다. 콜백이 지정되면 위젯 상태가 statespec과 일치하면 args로 호출됩니다.

state(statespec=None)

Modify or inquire widget state. If statespec is specified, sets the widget state according to it and return a new statespec indicating which flags were changed. If statespec is not specified, returns the currently enabled state flags.

statespec은 일반적으로 리스트나 튜플입니다.

Combobox

ttk.Combobox 위젯은 텍스트 필드를 값의 팝-다운(pop-down) 리스트와 결합합니다. 이 위젯은 Entry의 서브 클래스입니다.

Widget에서 상속된 메서드 Widget.cget(), Widget.configure(), Widget.identify(), Widget.instate() 및 Widget.state()와, Entry에서 상속된 메서드 Entry.bbox(), Entry.delete(), Entry.icursor(), Entry.index(), Entry.insert(), Entry.selection(), Entry.xview() 외에, ttk.Combobox에 설명된 다른 메서드가 있습니다.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

exportselection

불리언 값. 설정되면, 위젯 선택은 창 관리자 선택에 연결됩니다 (예를 들어, Misc.selection_get 을 호출하여 반환할 수 있습니다).

justify

위젯 내에서 텍스트가 정렬되는 방식을 지정합니다. “left”, “center” 또는 “right” 중 하나입니다.

height

팝-다운 목록 상자의 높이를 행 단위로 지정합니다.

postcommand

값을 표시하기 직전에 호출되는 (Misc.register로 등록할 수 있는) 스크립트. 표시할 값을 지정할 수 있습니다.

state

“normal”, “readonly” 또는 “disabled” 중 하나. “readonly” 상태에서는, 값을 직접 편집할 수 없고, 사용자는 드롭다운 목록에서 값을 선택할 수만 있습니다. “normal” 상태에서는, 텍스트 필드를 직접 편집할 수 있습니다. “disabled” 상태에서는, 상호 작용이 불가능합니다.

textvariable

값이 위젯 값에 연결된 이름을 지정합니다. 해당 이름과 관련된 값이 변경될 때마다, 위젯 값이 갱신되고, 그 반대도 마찬가지입니다. tkinter.StringVar를 참조하십시오.

values

드롭-다운 목록 상자에 표시할 값의 리스트를 지정합니다.

width

원하는 입력 창의 너비를 나타내는 정숫값을 위젯 글꼴의 평균 크기 문자 단위로 지정합니다.

가상 이벤트

콤보 박스 위젯은 사용자가 값 목록에서 요소를 선택할 때 <<ComboboxSelected>> 가상 이벤트를 생성합니다.

ttk.Combobox

class tkinter.ttk.Combobox

current(newindex=None)

newindex를 지정하면, 콤보 박스 값을 요소 위치 newindex로 설정합니다. 그렇지 않으면, 현재 값의 인덱스를 반환하거나 현재 값이 값 목록에 없으면 -1을 반환합니다.

get()

콤보 박스의 현재 값을 반환합니다.

set(value)

콤보 박스의 값을 value로 설정합니다.

Spinbox

ttk.Spinbox 위젯은 증가와 감소 화살표로 개선된 ttk.Entry입니다. 숫자나 문자열 값의 리스트에 사용할 수 있습니다. 이 위젯은 Entry의 서브 클래스입니다.

Widget에서 상속된 메서드 Widget.cget(), Widget.configure(), Widget.identify(), Widget.instate() 및 Widget.state()와, Entry에서 상속된 메서드 Entry.bbox(), Entry.delete(), Entry.icursor(), Entry.index(), Entry.insert(), Entry.xview() 외에도, ttk.Spinbox에 설명된 다른 메서드가 있습니다.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

from

부동 소수점 값. 설정하면, 감소 버튼이 감소할 최솟값입니다. from은 파이썬 키워드이므로, 인자로 사용될 때 from_을 사용해야 합니다.

to

부동 소수점 값. 설정되면, 증가 버튼이 증가할 최댓값입니다.

increment

부동 소수점 값. 증가/감소 버튼이 값을 변경할 양을 지정합니다. 기본값은 1.0입니다.

values

문자열이나 부동 소수점 값의 시퀀스. 지정되면, 증가/감소 버튼은 숫자를 늘리거나 줄이는 것이 아니라, 이 시퀀스에서 항목을 순환합니다.

wrap

불리언 값. True이면, 증가와 감소 버튼이 각각 to 값에서 from 값으로, from 값에서 to 값으로 순환합니다.

format

문자열 값. 증가/감소 버튼으로 설정된 숫자의 포맷을 지정합니다. “%W.Pf” 형식이어야 합니다, 여기서 W는 값의 패딩 된 너비, P는 정밀도, 그리고 ‘%’와 ‘f’는 리터럴 입니다.

command

파이썬 콜러블. 증가나 감소 버튼 중 하나를 누를 때마다 인자 없이 호출됩니다.

가상 이벤트

스핀 박스 위젯은 사용자가 <Up>을 누를 때 <<Increment>> 가상 이벤트를, 사용자가 <Down>을 누를 때 <<Decrement>> 가상 이벤트를 생성합니다.

ttk.Spinbox

class tkinter.ttk.Spinbox

get()

스핀 박스의 현재 값을 반환합니다.

set(value)

스핀 박스의 값을 value로 설정합니다.

Notebook

Ttk Notebook widget manages a collection of windows and displays a single one at a time. Each child window is associated with a tab, which the user may select to change the currently displayed window.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

height

존재하고 0보다 크면, 팬 영역(pane area)의 원하는 높이를 지정합니다 (내부 패딩이나 탭을 포함하지 않습니다). 그렇지 않으면, 모든 팬의 최대 높이가 사용됩니다.

padding

노트북 외부에 추가할 여분의 공간을 지정합니다. 패딩은 좌(left) 상(top) 우(right) 하(bottom) 최대 4개의 길이 명세 리스트입니다. 4개보다 적은 요소가 지정되면, bottom의 기본값은 top, right의 기본값은 left, top의 기본값은 left입니다.

width

존재하고 0보다 크면, 원하는 팬 영역 너비를 지정합니다 (내부 패딩을 포함하지 않습니다). 그렇지 않으면, 모든 팬의 최대 너비가 사용됩니다.

탭 옵션

탭에 대한 특정 옵션도 있습니다:

옵션

설명

state

“normal”, “disabled” 또는 “hidden”. “disabled” 이면, 탭을 선택할 수 없습니다. “hidden” 이면, 탭이 표시되지 않습니다.

sticky

자식 창이 창 영역 내에서 배치되는 방법을 지정합니다. 값은 0개 이상의 문자 “n”, “s”, “e” 또는 “w”를 포함하는 문자열입니다. 각 문자는 grid() 지오메트리 관리자에 따라, 자식 창이 붙을 변(북(north), 남(south), 동(east) 또는 서(west))을 나타냅니다.

padding

노트북과 이 팬 사이에 추가할 여분의 공간을 지정합니다. 문법은 이 위젯에서 사용하는 옵션 padding과 같습니다.

text

탭에 표시할 텍스트를 지정합니다.

image

탭에 표시할 이미지를 지정합니다. Widget에 설명된 옵션 image를 참조하십시오.

compound

옵션 text와 image가 모두 있을 때, 텍스트에 상대적으로 이미지를 표시하는 방법을 지정합니다. 유효한 값은 레이블 옵션을 참조하십시오.

underline

텍스트 문자열에서 밑줄 그을 문자의 인덱스(0에서 시작)를 지정합니다. Notebook.enable_traversal()이 호출되면 밑줄 있는 문자는 니모닉 활성화(mnemonic activation)에 사용됩니다.

탭 식별자

ttk.Notebook의 여러 가지 메서드에 존재하는 tab_id는 다음 형식 중 하나를 취할 수 있습니다:

0과 탭 수 사이의 정수

자식 창의 이름

탭을 식별하는 “@x,y” 형식의 위치 명세

The literal string “current”, which identifies the currently selected tab

탭 수를 반환하는 리터럴 문자열 “end” (Notebook.index()에만 유효합니다)

가상 이벤트

이 위젯은 새 탭을 선택한 후 <<NotebookTabChanged>> 가상 이벤트를 생성합니다.

ttk.Notebook

class tkinter.ttk.Notebook

add(child, **kw)

노트북에 새 탭을 추가합니다.

창이 현재 노트북으로 관리되지만 숨겨져 있으면, 창은 이전 위치로 복원됩니다.

사용 가능한 옵션 목록은 탭 옵션을 참조하십시오.

forget(tab_id)

tab_id로 지정된 탭을 제거하고, 연관된 창을 매핑 취소하고 관리 취소합니다.

hide(tab_id)

tab_id로 지정된 탭을 숨깁니다.

탭은 표시되지 않지만, 관련 창은 노트북에 의해 계속 관리되고 구성이 기억됩니다. 숨겨진 탭은 add() 명령으로 복원될 수 있습니다.

identify(x, y)

위치 x, y의 탭 요소 이름을 반환하거나, 없으면 비어있는 문자열을 반환합니다.

index(tab_id)

tab_id로 지정된 탭의 숫자 인덱스를 반환하거나, tab_id가 문자열 “end”이면 총 탭 수를 반환합니다.

insert(pos, child, **kw)

지정된 위치에 팬(pane)을 삽입합니다.

pos는 문자열 “end”, 정수 인덱스 또는 관리되는 자식의 이름입니다. 노트북에서 child를 이미 관리하고 있으면, 지정된 위치로 옮깁니다.

사용 가능한 옵션 목록은 탭 옵션을 참조하십시오.

select(tab_id=None)

지정된 tab_id를 선택합니다.

The associated child window will be displayed, and the previously selected window (if different) is unmapped. If tab_id is omitted, returns the widget name of the currently selected pane.

tab(tab_id, option=None, **kw)

특정 tab_id의 옵션을 조회하거나 수정합니다.

kw가 제공되지 않으면, 탭 옵션값의 딕셔너리를 반환합니다. option이 지정되면, 해당 option의 값을 반환합니다. 그렇지 않으면, 옵션을 해당 값으로 설정합니다.

tabs()

노트북에서 관리하는 창의 리스트를 반환합니다.

enable_traversal()

이 노트북이 포함된 최상위 창의 키보드 순회를 활성화합니다.

이것은 노트북을 포함하는 최상위 창에 대한 바인딩을 다음과 같이 확장합니다:

Control-Tab: 현재 선택된 탭 다음에 있는 탭을 선택합니다.

Shift-Control-Tab: 현재 선택된 탭 앞에 있는 탭을 선택합니다.

Alt-K: 여기서 K는 탭의 니모닉 (밑줄이 그어진) 문자이며, 해당 탭을 선택합니다.

중첩된 노트북을 포함하여, 단일 최상위 수준에 있는 여러 노트북의 순회를 활성화할 수 있습니다. 그러나, 모든 팬에 마스터로 있는 노트북이 있을 때만 노트북 순회가 제대로 작동합니다.

Progressbar

ttk.Progressbar 위젯은 장기 실행 작업의 상태를 보여줍니다. 두 가지 모드로 동작할 수 있습니다: 1) 수행할 총작업량을 기준으로 완료된 양을 표시하는 확정적(determinate) 모드와 2) 작업이 진행 중임을 사용자에게 알리는 애니메이션 표시를 제공하는 불확정적(indeterminate) 모드입니다.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

orient

“horizontal” 또는 “vertical” 중 하나입니다. 진행 막대의 방향을 지정합니다.

length

진행 막대의 긴 축의 길이를 지정합니다 (가로면 너비, 세로면 높이).

mode

“determinate” 또는 “indeterminate” 중 하나.

maximum

최댓값을 지정하는 숫자. 기본값은 100입니다.

value

진행 막대의 현재 값. “determinate” (확정적) 모드에서는, 완료된 작업량을 나타냅니다. “indeterminate” (불확정적) 모드에서는, 모듈로 maximum으로 해석됩니다; 즉, 진행 막대의 값이 maximum 증가하면 하나의 “사이클”이 완료됩니다.

variable

옵션값에 연결된 이름. 지정되면, 진행 막대의 값은 이 이름의 값이 수정될 때마다 이 이름의 값으로 자동 설정됩니다.

phase

읽기 전용 옵션. 위젯은 값이 0보다 크고 확정적 모드에서 최댓값보다 작을 때마다 이 옵션의 값을 주기적으로 증가시킵니다. 이 옵션은 현재 테마에서 추가 애니메이션 효과를 제공하는 데 사용할 수 있습니다.

ttk.Progressbar

class tkinter.ttk.Progressbar

start(interval=None)

자동 증가 모드를 시작합니다: interval 밀리초마다 Progressbar.step()을 호출하는 반복 타이머 이벤트를 예약합니다. 생략하면, interval의 기본값은 50밀리초입니다.

step(amount=None)

진행 막대의 값을 amount만큼 증가시킵니다.

생략하면 amount의 기본값은 1.0입니다.

stop()

자동 증가 모드를 중지합니다: 이 진행 막대에 대한 Progressbar.start()로 시작된 반복 타이머 이벤트를 취소합니다.

Separator

ttk.Separator 위젯은 가로나 세로 구분 막대를 표시합니다.

ttk.Widget에서 상속된 것 외에 다른 메서드는 없습니다.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

orient

“horizontal”(가로)이나 “vertical”(세로) 중 하나입니다. 구분 막대의 방향을 지정합니다.

Sizegrip

ttk.Sizegrip 위젯(확장 상자(grow box)라고도 합니다)을 사용하면 그립(grip)을 누르고 드래그하여 포함하는 최상위 창의 크기를 조정할 수 있습니다.

이 위젯에는 ttk.Widget에서 상속된 것 외에 특정 옵션이나 메서드가 없습니다.

플랫폼별 노트

On macOS, toplevel windows automatically include a built-in size grip by default. Adding a Sizegrip is harmless, since the built-in grip will just mask the widget.

버그

포함하는 최상위 수준의 위치가 화면의 오른쪽이나 아래쪽을 기준으로 지정되면 (예를 들어 ….), Sizegrip 위젯은 창의 크기를 조정하지 않습니다.

이 위젯은 “동남쪽” 크기 조정만 지원합니다.

Treeview

ttk.Treeview 위젯은 계층적 항목 컬렉션을 표시합니다. 각 항목에는 텍스트 레이블, 선택적 이미지 및 선택적 데이터값 목록이 있습니다. 데이터값은 트리 레이블 다음에 연속되는 열에 표시됩니다.

위젯 옵션 displaycolumns를 설정하여 데이터값이 표시되는 순서를 제어할 수 있습니다. 트리 위젯은 열 제목을 표시할 수도 있습니다. 위젯 옵션 열에 나열된 숫자나 기호 이름으로 열에 액세스 할 수 있습니다. 열 식별자를 참조하십시오.

각 항목은 고유한 이름으로 식별됩니다. 호출자가 제공하지 않으면 위젯은 항목 ID를 생성합니다. {}라고 이름 붙은, 구별되는 루트 항목이 있습니다. 루트 항목 자체는 표시되지 않습니다; 이것의 자식들이 계층 구조의 최상위 수준에 나타납니다.

각 항목에는 이벤트 바인딩을 개별 항목과 연관시키고 항목의 모양을 제어하는 데 사용할 수 있는 태그 목록이 있습니다.

Treeview 위젯은 스크롤 가능한 위젯 옵션에 설명된 옵션과 Treeview.xview()와 Treeview.yview() 메서드에 따라 가로와 세로 스크롤을 지원합니다.

옵션

이 위젯은 다음과 같은 특정 옵션을 받아들입니다:

옵션

설명

columns

열 수와 이름을 지정하는, 열 식별자 리스트.

displaycolumns

표시할 데이터 열과 표시되는 순서를 지정하는 열 식별자 (기호나 정수 인덱스) 리스트, 또는 문자열 “#all”.

height

보여야 하는 행 수를 지정합니다. 참고: 요청된 너비는 열 너비의 합계로 결정됩니다.

padding

위젯의 내부 패딩을 지정합니다. 패딩은 최대 4개의 길이 명세 리스트입니다.

selectmode

내장 클래스 바인딩이 선택을 관리하는 방법을 제어합니다. “extended”, “browse” 또는 “none” 중 하나입니다. “extended”(기본값)로 설정하면, 여러 항목을 선택할 수 있습니다. “browse”이면, 한 번에 하나의 항목 만 선택됩니다. “none”이면 선택이 변경되지 않습니다.

이 옵션의 값과 관계없이, 응용 프로그램 코드와 태그 바인딩은 원하는 대로 선택을 설정할 수 있음에 유의하십시오.

show

표시할 트리의 요소를 지정하는, 다음 값 중 0개 이상을 포함하는 리스트.

tree: 열 #0에 트리 레이블을 표시합니다.

headings: 제목 행을 표시합니다.

기본값은 “tree headings” 입니다, 즉, 모든 요소를 표시합니다.

참고: show=”tree” 가 지정되지 않은 경우에도, #0 열은 항상 트리 열을 나타냅니다.

항목 옵션

insert와 item 위젯 명령에서 항목에 대해 다음 항목 옵션을 지정할 수 있습니다.

옵션

설명

text

항목에 표시할 텍스트 레이블.

image

레이블 왼쪽에 표시되는, Tk 이미지.

values

항목과 관련된 값의 리스트.

각 항목은 위젯 옵션 열과 같은 수의 값을 가져야 합니다. 열보다 적은 값이 있으면, 나머지 값은 비어 있다고 가정합니다. 열보다 많은 값이 있으면, 추가 값은 무시됩니다.

open

항목의 자식을 표시할지를 나타내는 True/False 값.

tags

이 항목과 관련된 태그의 리스트.

태그 옵션

태그에 다음 옵션을 지정할 수 있습니다:

옵션

설명

foreground

텍스트 전경색을 지정합니다.

background

셀이나 항목 배경색을 지정합니다.

font

텍스트를 그릴 때 사용할 글꼴을 지정합니다.

image

항목의 image 옵션이 비어있는 경우, 항목 이미지를 지정합니다.

열 식별자

열 식별자는 다음 형식 중 하나를 취합니다:

열 옵션 목록에 있는 기호 이름.

n번째 데이터 열을 지정하는, 정수 n.

#n 형식의 문자열, 여기서 n은 정수이며 n번째 표시 열을 지정합니다.

노트:

항목의 옵션 값은 저장된 순서와 다른 순서로 표시될 수 있습니다.

show=”tree”가 지정되지 않은 경우에도, #0 열은 항상 트리 열을 나타냅니다.

데이터 열 번호는 항목의 옵션 값 리스트에 대한 인덱스입니다; 표시 열 번호는 값이 표시되는 트리의 열 번호입니다. 트리 레이블은 열 #0 에 표시됩니다. displaycolumns 옵션을 설정하지 않으면, 데이터 열 n이 열 #n+1 에 표시됩니다. 다시, #0 열은 항상 트리 열을 나타냅니다.

가상 이벤트

Treeview 위젯은 다음과 같은 가상 이벤트를 생성합니다.

이벤트

설명

<<TreeviewSelect>>

선택이 변경될 때마다 생성됩니다.

<<TreeviewOpen>>

포커스 항목을 open=True 로 설정하기 직전에 생성됩니다.

<<TreeviewClose>>

포커스 항목을 open=False 로 설정한 직후 생성됩니다.

Treeview.focus()와 Treeview.selection() 메서드를 사용하여 영향을 받는 항목이나 항목들을 결정할 수 있습니다.

ttk.Treeview

class tkinter.ttk.Treeview

bbox(item, column=None)

지정된 item의 경계 상자(트리 뷰 위젯의 창에 상대적인)를 (x, y, 너비, 높이) 형식으로 반환합니다.

column을 지정하면, 해당 셀의 경계 상자를 반환합니다. item이 보이지 않으면 (즉, 닫힌 항목의 자손이거나 화면 밖으로 스크롤 되면) 빈 문자열을 반환합니다.

get_children(item=None)

item에 속하는 자식의 리스트를 반환합니다.

item이 지정되지 않으면, 루트 자식을 반환합니다.

set_children(item, *newchildren)

item의 자식을 newchildren으로 바꿉니다.

item에 있지만 newchildren에 없는 자식은 트리에서 분리됩니다. newchildren의 어떤 항목도 item의 조상이 될 수 없습니다. newchildren을 지정하지 않으면 item의 자식이 분리됨에 유의하십시오.

column(column, option=None, **kw)

지정된 column에 대한 옵션을 조회하거나 수정합니다.

kw가 제공되지 않으면, 열 옵션 값의 딕셔너리를 반환합니다. option이 지정되면 해당 option의 값이 반환됩니다. 그렇지 않으면, 옵션을 해당 값으로 설정합니다.

유효한 옵션/값은 다음과 같습니다:

id

열 이름을 반환합니다. 이것은 읽기 전용 옵션입니다.

anchor: One of the standard Tk anchor values.

이 열의 텍스트가 셀을 기준으로 정렬되는 방법을 지정합니다.

minwidth: width

열의 픽셀 단위의 최소 너비. 위젯의 크기가 조정되거나 사용자가 열을 드래그할 때 트리 뷰 위젯은 이 옵션으로 지정된 것보다 작게 열을 만들지 않습니다.

stretch: True/False

위젯 크기를 조정할 때 열 너비를 조정할지를 지정합니다.

width: width

열의 픽셀 단위 너비.

트리 열을 구성하려면, column = “#0” 으로 호출하십시오.

delete(*items)

지정된 items와 그들의 모든 자손을 삭제합니다.

루트 항목은 삭제되지 않을 수 있습니다.

detach(*items)

지정된 items를 모두 트리에서 연결 해제합니다.

항목과 그들의 모든 자손은 여전히 존재하며, 트리의 다른 지점에 다시 삽입될 수 있지만, 표시되지는 않습니다.

루트 아이템은 분리되지 않을 수 있습니다.

exists(item)

지정된 item이 트리에 있으면 True를 반환합니다.

focus(item=None)

item이 지정되면, 포커스 항목을 item으로 설정합니다. 그렇지 않으면, 현재 포커스 항목을 반환하거나, 없으면 ‘’ 을 반환합니다.

heading(column, option=None, **kw)

지정된 column에 대한 제목(heading) 옵션을 조회하거나 수정합니다.

kw가 제공되지 않으면, 제목 옵션값의 딕셔너리를 반환합니다. option이 지정되면 해당 option의 값이 반환됩니다. 그렇지 않으면, 옵션을 해당 값으로 설정합니다.

유효한 옵션/값은 다음과 같습니다:

text: text

열 제목에 표시할 텍스트.

image: imageName

열 제목의 오른쪽에 표시할 이미지를 지정합니다.

anchor: anchor

제목 텍스트를 정렬하는 방법을 지정합니다. 표준 Tk 앵커값 중 하나입니다.

command: callback

제목 레이블을 누를 때 호출되는 콜백.

트리 열 제목을 구성하려면, column = “#0” 으로 호출하십시오.

identify(component, x, y)

x 와 y로 주어진 점 밑에 있는 지정된 component에 대한 설명을 반환하거나, 해당 component가 해당 위치에 없으면 빈 문자열을 반환합니다.

identify_row(y)

y 위치에 있는 항목의 항목 ID를 반환합니다.

identify_column(x)

위치 x에 있는 셀의 데이터 열 식별자를 반환합니다.

트리 열의 ID는 #0 입니다.

identify_region(x, y)

다음 중 하나를 반환합니다:

영역(region)

의미

heading

트리 제목 영역.

separator

두 열 제목 사이의 공간.

tree

트리 영역.

cell

데이터 셀.

가용성: Tk 8.6.

identify_element(x, y)

위치 x, y에 있는 요소를 반환합니다.

가용성: Tk 8.6.

index(item)

부모의 자식 리스트에서 item의 정수 인덱스를 반환합니다.

insert(parent, index, iid=None, **kw)

새 항목을 만들고 새로 만들어진 항목의 항목 ID를 반환합니다.

parent는 부모 항목의 항목 ID이거나, 새 최상위 항목을 만들려면 빈 문자열입니다. index는 정수이거나, “end” 값으로, 부모의 자식 리스트에서 새 항목을 삽입할 위치를 지정합니다. index가 0보다 작거나 같으면, 새 노드가 처음에 삽입됩니다; index가 현재 자식 수보다 크거나 같으면, 끝에 삽입됩니다. iid가 지정되면, 항목 식별자로 사용됩니다; iid는 아직 트리에 존재하지 않아야 합니다. 그렇지 않으면, 새로운 고유 식별자가 생성됩니다.

See Item Options for the list of available options.

item(item, option=None, **kw)

지정된 item에 대한 옵션을 조회하거나 수정합니다.

옵션이 제공되지 않으면 항목에 대한 옵션/값이 포함된 딕셔너리가 반환됩니다. option이 지정되면 해당 옵션의 값이 반환됩니다. 그렇지 않으면, 옵션을 kw에서 제공한 해당 값으로 설정합니다.

move(item, parent, index)

item을 parent의 자식 리스트에서 index 위치로 이동합니다.

항목을 그 자신의 자손 항목 중 하나 밑으로 이동하는 것은 불법입니다. index가 0보다 작거나 같으면, item이 처음으로 이동합니다; 자식 수보다 크거나 같으면, 끝으로 이동합니다. item이 분리되었으면 다시 연결됩니다.

next(item)

item의 다음 형제의 식별자를 반환하거나, item이 부모의 마지막 자식이면 ‘’ 을 반환합니다.

parent(item)

item의 부모 ID를 반환하거나, item이 계층의 최상위에 있으면 ‘’ 을 반환합니다.

prev(item)

item의 이전 형제의 식별자를 반환하거나, item이 부모의 첫 번째 자식이면 ‘’ 을 반환합니다.

reattach(item, parent, index)

Treeview.move()의 별칭.

see(item)

item이 보이도록 합니다.

item의 모든 조상의 open 옵션을 True로 설정하고, 필요하면 위젯을 스크롤 하여 item이 트리의 보이는 부분 내에 있도록 합니다.

selection()

선택한 항목의 튜플을 반환합니다.

버전 3.8에서 변경: selection()은 더는 인자를 취하지 않습니다. 선택 상태를 변경하려면 다음 선택 메서드를 사용하십시오.

selection_set(*items)

items가 새로운 선택이 됩니다.

버전 3.6에서 변경: items는 단일 튜플이 아닌 별도의 인자로 전달될 수 있습니다.

selection_add(*items)

선택에 items를 추가합니다.

버전 3.6에서 변경: items는 단일 튜플이 아닌 별도의 인자로 전달될 수 있습니다.

selection_remove(*items)

선택에서 items를 제거합니다.

버전 3.6에서 변경: items는 단일 튜플이 아닌 별도의 인자로 전달될 수 있습니다.

selection_toggle(*items)

items에 있는 각 항목의 선택 상태를 토글 합니다.

버전 3.6에서 변경: items는 단일 튜플이 아닌 별도의 인자로 전달될 수 있습니다.

set(item, column=None, value=None)

하나의 인자로는, 지정된 item에 대한 열/값 쌍 딕셔너리를 반환합니다. 두 개의 인자를 사용하면, 지정된 column의 현재 값을 반환합니다. 세 개의 인자를 사용하면, 지정된 item의 지정된 column의 값을, 지정된 value로 설정합니다.

tag_bind(tagname, sequence=None, callback=None)

주어진 이벤트 sequence에 대한 콜백을 태그 tagname에 바인딩합니다. 이벤트가 항목에 전달되면, 각 항목의 태그 옵션에 대한 콜백이 호출됩니다.

tag_configure(tagname, option=None, **kw)

지정된 tagname에 대한 옵션을 조회하거나 수정합니다.

kw가 제공되지 않으면, tagname에 대한 옵션 설정의 딕셔너리를 반환합니다. option이 지정되면, 지정된 tagname에 대한 해당 option의 값을 반환합니다. 그렇지 않으면, 옵션을 주어진 tagname에 대해 해당하는 값으로 설정합니다.

tag_has(tagname, item=None)

item이 지정되면, 지정된 item에 지정된 tagname이 있는지에 따라 1이나 0을 반환합니다. 그렇지 않으면, 지정된 태그가 있는 모든 항목의 리스트를 반환합니다.

가용성: Tk 8.6

xview(*args)

트리 뷰의 가로 위치를 조회하거나 수정합니다.

yview(*args)

트리 뷰의 수직 위치를 조회하거나 수정합니다.

Ttk 스타일링

ttk의 각 위젯에는 스타일이 지정되는데, 이 스타일은 요소 옵션의 동적 및 기본 설정과 함께 위젯을 구성하는 요소 집합과 배열 방식을 지정합니다. 기본적으로 스타일 이름은 위젯의 클래스 이름과 같지만, 위젯의 스타일 옵션으로 재정의될 수 있습니다. 위젯의 클래스 이름을 모르면, Misc.winfo_class() 메서드(somewidget.winfo_class())를 사용하십시오.

더 보기

Tcl’2004 conference presentation [https://tktable.sourceforge.net/tile/tile-tcl2004.pdf]

이 문서는 테마 엔진의 작동 방식을 설명합니다

class tkinter.ttk.Style

이 클래스는 스타일 데이터베이스를 조작하는 데 사용됩니다.

configure(style, query_opt=None, **kw)

style에서 지정된 옵션의 기본값을 조회하거나 설정합니다.

kw의 각 키는 옵션이며 각 값은 해당 옵션의 값을 식별하는 문자열입니다.

예를 들어, 모든 기본 버튼을 패딩이 있고 배경색이 다른 평평한 버튼으로 바꾸려면:

from tkinter import ttk
import tkinter

root = tkinter.Tk()

ttk.Style().configure("TButton", padding=6, relief="flat",
   background="#ccc")

btn = ttk.Button(text="Sample")
btn.pack()

root.mainloop()

map(style, query_opt=None, **kw)

style에서 지정된 옵션의 동적 값을 조회하거나 설정합니다.

kw의 각 키는 옵션이며 각 값은 (일반적으로) 튜플, 리스트 또는 다른 선호하는 것에 그룹화된 상태 명세(statespecs)를 포함하는 리스트나 튜플이어야 합니다. 상태 명세(statespec)는 하나 이상의 상태와 그다음에 값이 오는 복합체입니다.

예를 들면 더 이해하기 쉽습니다:

import tkinter
from tkinter import ttk

root = tkinter.Tk()

style = ttk.Style()
style.map("C.TButton",
    foreground=[('pressed', 'red'), ('active', 'blue')],
    background=[('pressed', '!disabled', 'black'), ('active', 'white')]
    )

colored_btn = ttk.Button(text="Test", style="C.TButton").pack()

root.mainloop()

옵션의 (상태들, 값) 시퀀스의 순서는 중요함에 유의하십시오. 예를 들어, foreground 옵션에서 순서가 [('active', 'blue'), ('pressed', 'red')]로 변경되면, 예를 들어, 위젯이 active 나 pressed 상태일 때 결과는 파란색 전경이 됩니다.

lookup(style, option, state=None, default=None)

style에서 option에 지정된 값을 반환합니다.

state가 지정되면, 하나 이상의 상태 시퀀스일 것으로 기대됩니다. default 인자가 설정되면, 옵션에 대한 명세가 없을 때 폴 백값으로 사용됩니다.

Button이 기본적으로 사용하는 글꼴을 확인하려면:

from tkinter import ttk

print(ttk.Style().lookup("TButton", "font"))

layout(style, layoutspec=None)

주어진 style에 대한 위젯 레이아웃을 정의합니다. layoutspec이 생략되면, 지정된 스타일의 레이아웃 명세를 반환합니다.

지정되면, layoutspec은 리스트나 다른 시퀀스 형(문자열 제외)이어야 합니다. 여기서 각 항목은 튜플이어야 하고 첫 번째 항목은 레이아웃 이름이고 두 번째 항목은 레이아웃에 설명된 형식이어야 합니다.

형식을 이해하려면, 다음 예제를 참조하십시오 (유용한 것은 아닙니다):

from tkinter import ttk
import tkinter

root = tkinter.Tk()

style = ttk.Style()
style.layout("TMenubutton", [
   ("Menubutton.background", None),
   ("Menubutton.button", {"children":
       [("Menubutton.focus", {"children":
           [("Menubutton.padding", {"children":
               [("Menubutton.label", {"side": "left", "expand": 1})]
           })]
       })]
   }),
])

mbtn = ttk.Menubutton(text='Text')
mbtn.pack()
root.mainloop()

element_create(elementname, etype, *args, **kw)

Create a new element in the current theme, of the given etype which is expected to be either “image”, “from” or “vsapi”. The latter is only available in Tk 8.6 on Windows.

“image”를 사용하면, args는 기본 이미지 이름과 그 뒤에 오는 statespec/value 쌍 (이것이 이미지 명세(imagespec)입니다)을 포함해야 하며, kw에는 다음 옵션이 올 수 있습니다:

border=패딩

패딩은 각각 좌(left), 상(top), 우(right), 하(bottom) 테두리를 지정하는 최대 4개의 정수 리스트입니다.

height=높이

요소의 최소 높이를 지정합니다. 0보다 작으면, 기본 이미지의 높이가 기본값으로 사용됩니다.

padding=패딩

요소의 내부 패딩을 지정합니다. 지정하지 않으면 기본값은 border의 값입니다.

sticky=명세

최종 파슬(parcel) 내에 이미지를 배치하는 방법을 지정합니다. 명세에는 0개 이상의 문자 “n”, “s”, “w” 또는 “e” 가 포함됩니다.

width=너비

요소의 최소 너비를 지정합니다. 0보다 작으면, 기본 이미지의 너비가 기본값으로 사용됩니다.

Example:

img1 = tkinter.PhotoImage(master=root, file='button.png')
img1 = tkinter.PhotoImage(master=root, file='button-pressed.png')
img1 = tkinter.PhotoImage(master=root, file='button-active.png')
style = ttk.Style(root)
style.element_create('Button.button', 'image',
                     img1, ('pressed', img2), ('active', img3),
                     border=(2, 4), sticky='we')

“from”이 etype의 값으로 사용되면, element_create()는 기존 요소를 복제합니다. args는 요소를 복제할 테마 이름(themename)과, 선택적으로 요소를 복제할 요소를 포함할 것으로 기대됩니다. 복제할 요소를 지정하지 않으면, 빈 요소가 사용됩니다. kw는 폐기됩니다.

Example:

style = ttk.Style(root)
style.element_create('plain.background', 'from', 'default')

If “vsapi” is used as the value of etype, element_create() will create a new element in the current theme whose visual appearance is drawn using the Microsoft Visual Styles API which is responsible for the themed styles on Windows XP and Vista. args is expected to contain the Visual Styles class and part as given in the Microsoft documentation followed by an optional sequence of tuples of ttk states and the corresponding Visual Styles API state value. kw may have the following options:

padding=패딩

Specify the element’s interior padding. padding is a list of up to four integers specifying the left, top, right and bottom padding quantities respectively. If fewer than four elements are specified, bottom defaults to top, right defaults to left, and top defaults to left. In other words, a list of three numbers specify the left, vertical, and right padding; a list of two numbers specify the horizontal and the vertical padding; a single number specifies the same padding all the way around the widget. This option may not be mixed with any other options.

margins=padding

Specifies the elements exterior padding. padding is a list of up to four integers specifying the left, top, right and bottom padding quantities respectively. This option may not be mixed with any other options.

width=너비

Specifies the width for the element. If this option is set then the Visual Styles API will not be queried for the recommended size or the part. If this option is set then height should also be set. The width and height options cannot be mixed with the padding or margins options.

height=높이

Specifies the height of the element. See the comments for width.

Example:

style = ttk.Style(root)
style.element_create('pin', 'vsapi', 'EXPLORERBAR', 3, [
                     ('pressed', '!selected', 3),
                     ('active', '!selected', 2),
                     ('pressed', 'selected', 6),
                     ('active', 'selected', 5),
                     ('selected', 4),
                     ('', 1)])
style.layout('Explorer.Pin',
             [('Explorer.Pin.pin', {'sticky': 'news'})])
pin = ttk.Checkbutton(style='Explorer.Pin')
pin.pack(expand=True, fill='both')

버전 3.13에서 변경: Added support of the “vsapi” element factory.

element_names()

현재 테마에 정의된 요소 목록을 반환합니다.

element_options(elementname)

elementname의 옵션 리스트를 반환합니다.

theme_create(themename, parent=None, settings=None)

새로운 테마를 만듭니다.

themename이 이미 존재하면 에러입니다. parent가 지정되면, 새 테마는 부모 테마에서 스타일, 요소 및 레이아웃을 상속합니다. settings가 있으면, theme_settings()에 사용되는 것과 같은 문법일 것으로 기대됩니다.

theme_settings(themename, settings)

현재 테마를 themename으로 임시 설정하고, 지정된 settings를 적용한 다음 이전 테마를 복원합니다.

settings의 각 키는 스타일이며 각 값에는 ‘configure’, ‘map’, ‘layout’ 및 ‘element create’ 키가 포함될 수 있으며 각각 Style.configure(), Style.map(), Style.layout() 및 Style.element_create()가 지정한 것과 같은 형식을 갖습니다.

예를 들어, 기본 테마의 Combobox를 약간 변경해 봅시다:

from tkinter import ttk
import tkinter

root = tkinter.Tk()

style = ttk.Style()
style.theme_settings("default", {
   "TCombobox": {
       "configure": {"padding": 5},
       "map": {
           "background": [("active", "green2"),
                          ("!disabled", "green4")],
           "fieldbackground": [("!disabled", "green3")],
           "foreground": [("focus", "OliveDrab1"),
                          ("!disabled", "OliveDrab2")]
       }
   }
})

combo = ttk.Combobox().pack()

root.mainloop()

theme_names()

알려진 모든 테마의 리스트를 반환합니다.

theme_use(themename=None)

themename이 제공되지 않으면, 사용 중인 테마를 반환합니다. 그렇지 않으면, 현재 테마를 themename으로 설정하고, 모든 위젯을 새로 고치고 <<ThemeChanged>> 이벤트를 방출합니다.

레이아웃

A layout can be just None, if it takes no options, or a dict of options specifying how to arrange the element. The layout mechanism uses a simplified version of the pack geometry manager: given an initial cavity, each element is allocated a parcel.

유효한 옵션/값은 다음과 같습니다:

side: whichside

요소를 배치할 캐비티(cavity)의 변을 지정합니다; 상(top), 우(right), 하(bottom) 또는 좌(left) 중 하나입니다. 생략하면, 요소가 전체 캐비티를 차지합니다.

sticky: nswe

할당된 파슬(parcel)에서 요소가 배치되는 위치를 지정합니다.

unit: 0 or 1

1로 설정하면, Widget.identify() 등의 목적으로 요소와 그것의 모든 자손이 단일 요소로 처리됩니다. 그립이 있는 스크롤 막대 썸(thumbs)과 같은 것들에 사용됩니다.

children: [sublayout… ]

요소 안에 배치할 요소 리스트를 지정합니다. 각 요소는 첫 번째 항목이 레이아웃 이름이고, 다른 하나는 레이아웃인 튜플(또는 다른 시퀀스 형)입니다.

IDLE

소스 코드: Lib/idlelib/ [https://github.com/python/cpython/tree/main/Lib/idlelib/]

IDLE은 파이썬의 통합 개발 및 학습 환경입니다.

IDLE에는 다음과 같은 기능이 있습니다:

크로스 플랫폼: 윈도우, 유닉스 및 macOS에서 거의 같게 작동합니다

코드 입력, 출력 및 에러 메시지를 채색하는 파이썬 셸 창 (대화식 인터프리터)

다중 실행 취소, 파이썬 색상 지정, 스마트 들여쓰기, 호출 팁, 자동 완성 및 기타 기능이 있는 다중 창 텍스트 편집기

모든 창 내에서 검색, 편집기 창 내에서 교체 및 여러 파일을 통한 검색 (grep)

지속적인 중단점(breakpoints), 스테핑(stepping) 및 전역과 지역 이름 공간 보기가 있는 디버거

구성, 브라우저 및 기타 대화 상자

메뉴

IDLE에는 두 가지 메인 창 유형이 있습니다, 셸 창과 편집기 창. 여러 개의 편집기 창을 동시에 가질 수 있습니다. 윈도우와 리눅스에서는, 각각 자신의 최상위 메뉴가 있습니다. 아래에 설명된 각 메뉴는 어떤 창 유형과 관련되는지를 나타냅니다.

가령 Edit => Find in Files 에서 사용되는 것과 같은 출력 창은 편집기 창의 하위 유형입니다. 현재 같은 최상위 메뉴가 있지만, 기본 제목과 문맥 메뉴가 다릅니다.

macOS에는, 하나의 응용 프로그램 메뉴가 있습니다. 현재 선택된 창에 따라 동적으로 변경됩니다. IDLE 메뉴가 있으며, 아래 설명된 일부 항목은 Apple 지침에 따라 이동됩니다.

File 메뉴 (셸과 편집기)

New File

새 파일 편집 창을 만듭니다.

Open…

열기 대화 상자로 기존 파일을 엽니다.

Open Module…

기존 모듈을 엽니다 (sys.path를 검색합니다).

Recent Files

최근 파일의 목록을 엽니다. 하나를 클릭하여 엽니다.

Module Browser

현재 편집기 파일의 함수, 클래스 및 메서드를 트리 구조로 표시합니다. 셸에서, 모듈을 먼저 여십시오.

Path Browser

sys.path 디렉터리, 모듈, 함수, 클래스 및 메서드를 트리 구조로 표시합니다.

Save

현재 창을 (있다면) 연관된 파일에 저장합니다. 열거나 마지막으로 저장한 이후에 변경된 창에는 창 제목 앞뒤에 * 가 있습니다. 연결된 파일이 없으면, 대신 Save As 를 수행합니다.

Save As…

Save the current window with a Save As dialog. The file saved becomes the new associated file for the window. (If your file namager is set to hide extensions, the current extension will be omitted in the file name box. If the new filename has no ‘.’, ‘.py’ and ‘.txt’ will be added for Python and text files, except that on macOS Aqua,’.py’ is added for all files.)

Save Copy As…

Save the current window to different file without changing the associated file. (See Save As note above about filename extensions.)

Print Window

현재 창을 기본 프린터로 인쇄합니다.

Close Window

Close the current window (if an unsaved editor, ask to save; if an unsaved Shell, ask to quit execution). Calling exit() or close() in the Shell window also closes Shell. If this is the only window, also exit IDLE.

Exit IDLE

Close all windows and quit IDLE (ask to save unsaved edit windows).

Edit 메뉴 (셸과 편집기)

Undo

현재 창에 대한 마지막 변경을 되돌립니다. 최대 1000개의 변경을 되돌릴 수 있습니다.

Redo

마지막으로 되돌린 변경을 현재 창에 다시 실행합니다.

Select All

현재 창의 전체 내용을 선택합니다.

Cut

선택 사항을 시스템 전체 클립 보드에 복사합니다; 그런 다음 선택을 삭제합니다.

Copy

선택 사항을 시스템 전체 클립 보드에 복사합니다.

Paste

시스템 전체 클립 보드의 내용을 현재 창에 삽입합니다.

클립 보드 기능은 문맥 메뉴에서도 사용할 수 있습니다.

Find…

많은 옵션이 제공되는 검색 대화 상자를 엽니다

Find Again

마지막 검색이 있으면 반복합니다.

Find Selection

현재 선택된 문자열이 있으면 검색합니다.

Find in Files…

파일 검색 대화 상자를 엽니다. 새로운 출력 창에 결과를 넣습니다.

Replace…

검색과 치환 대화 상자를 엽니다.

Go to Line

요청한 줄의 시작 부분으로 커서를 이동하고 해당 줄을 표시합니다. 파일 끝을 지나는 요청은 파일의 끝으로 갑니다. 모든 선택을 취소하고 줄과 열 상태를 갱신합니다.

Show Completions

기존 이름을 선택할 수 있는 스크롤 할 수 있는 목록을 엽니다. 아래의 편집 및 탐색 섹션에서 완성을 참조하십시오.

Expand Word

같은 창에서 전체 단어와 일치하도록 입력한 접두사를 확장합니다; 다른 확장을 얻으려면 반복하십시오.

Show Call Tip

함수에 대해 닫히지 않은 괄호 뒤에서, 함수 매개 변수 힌트가 있는 작은 창을 엽니다. 아래의 편집과 탐색 섹션에서 콜팁을 참조하십시오.

Show Surrounding Parens

주변 괄호를 강조 표시합니다.

Format 메뉴 (편집기 창 전용)

Format Paragraph

주석 블록이나 여러 줄 문자열의 빈 줄로 구분되는 현재 단락이나 문자열에서 선택한 줄을 다시 포맷합니다. 단락의 모든 줄은 N 열 미만으로 포맷되며, 여기서 N은 기본적으로 72입니다.

Indent Region

선택한 줄을 들여쓰기 너비(기본값은 4개의 스페이스)만큼 오른쪽으로 이동합니다.

Dedent Region

선택한 줄을 들여쓰기 너비(기본값은 4개의 스페이스)만큼 왼쪽으로 이동합니다.

Comment Out Region

선택한 줄 앞에 ## 을 삽입합니다.

Uncomment Region

선택한 줄에서 선행 # 이나 ## 을 제거합니다.

Tabify Region

연속된 선행 스페이스를 탭으로 바꿉니다. (참고: 4개의 스페이스 블록을 사용하여 파이썬 코드를 들여 쓰는 것이 좋습니다.)

Untabify Region

모든 탭을 올바른 수의 스페이스로 바꿉니다.

Toggle Tabs

스페이스와 탭 들여쓰기 간을 전환하는 대화 상자를 엽니다.

New Indent Width

들여쓰기 너비를 변경하는 대화 상자를 엽니다. 파이썬 커뮤니티에서 받아들여지는 기본값은 4개의 스페이스입니다.

Strip Trailing Chitespace

여러 줄 문자열 내의 줄을 포함하여, 각 줄에 str.rstrip을 적용하여 줄의 마지막 비 공백 문자 뒤의 후행 스페이스와 기타 공백 문자를 제거합니다. 셸 창을 제외하고, 파일 끝에서 추가 줄 바꿈을 제거합니다.

Run 메뉴 (편집기 창 전용)

Run Module

Check Module을 수행합니다. 에러가 없으면, 셸을 다시 시작하여 환경을 정리한 다음, 모듈을 실행합니다. 출력은 셸 창에 표시됩니다. 출력에는 print나 write를 사용해야 함에 유의하십시오. 실행이 완료되면, 셸은 포커스를 유지하고 프롬프트를 표시합니다. 이 시점에서, 실행 결과를 대화식으로 탐색할 수 있습니다. 이것은 명령 줄에서 python -i file로 파일을 실행하는 것과 유사합니다.

Run… Customized

Run Module과 같지만, 사용자 정의 설정으로 모듈을 실행합니다. 명령 줄 인자(Command Line Arguments)는 명령 줄에 전달된 것처럼 sys.argv를 확장합니다. 다시 시작하지 않고 모듈을 셸에서 실행할 수 있습니다.

Check Module

편집기 창에 현재 열려 있는 모듈의 문법을 검사합니다. 모듈이 저장되지 않았으면 IDLE은 설정 대화 상자의 General 탭에서 선택한 대로 사용자에게 저장을 요구하거나 자동 저장합니다. 문법 에러가 있으면, 대략적인 위치가 편집기 창에 표시됩니다.

Python Shell

파이썬 셸 창을 열거나 깨웁니다.

Shell 메뉴 (셸 창 전용)

View Last Restart

셸 창을 마지막 셸 재시작으로 스크롤 합니다.

Restart Shell

셸을 다시 시작하여 환경을 정리하고 디스플레이와 예외 처리를 재설정합니다.

Previous History

히스토리에서 현재 항목과 일치하는 이전 명령을 순환합니다.

Next History

히스토리에서 현재 항목과 일치하는 다음 명령을 순환합니다.

Interrupt Execution

실행 중인 프로그램을 중지합니다.

Debug 메뉴 (셸 창 전용)

Go to File/Line

커서가 놓인 현재 줄과 줄 위에서 파일명과 줄 번호는 찾습니다. 발견되면, (파일이 아직 열려 있지 않으면 파일을 열고) 줄을 보여줍니다. 이를 사용하여 예외 트레이스백에서 참조된 소스 줄과 Find in Files에서 찾은 줄을 볼 수 있습니다. 셸 창과 출력 창의 문맥 메뉴에서도 사용할 수 있습니다.

Debugger (toggle)

활성화되면, 셸에 입력되거나 편집기에서 실행된 코드가 디버거에서 실행됩니다. 편집기에서, 문맥 메뉴를 사용하여 중단점을 설정할 수 있습니다. 이 기능은 아직 불완전하고 다소 실험적입니다.

Stack Viewer

locals와 globals에 대한 액세스와 함께, 트리 위젯에 마지막 예외의 스택 트레이스백을 표시합니다.

Auto-open Stack Viewer

처리되지 않은 예외에서 스택 뷰어를 자동으로 여는 것을 전환합니다.

Options 메뉴 (셸과 편집기)

Configure IDLE

구성 대화 상자를 열고 다음과 같은 것들에 대한 설정을 변경합니다: 글꼴, 들여쓰기, 키 바인딩, 텍스트 색상 테마, 시작 창과 크기, 추가 도움말 소스 및 확장. macOS의 경우, 응용 프로그램 메뉴에서 Preferences를 선택하여 구성 대화 상자를 여십시오. 자세한 내용은, 도움말과 환경 설정에서 환경 설정을 참조하십시오.

대부분의 구성 옵션은 모든 창이나 모든 미래 창에 적용됩니다. 아래의 옵션 항목은 활성 창에만 적용됩니다.

Show/Hide Code Context (편집기 창 전용)

편집 창의 상단에 창의 상단 위로 스크롤 된 코드의 블록 컨텍스트를 표시하는 팬을 엽니다. 아래의 편집과 탐색 섹션에서 코드 컨텍스트를 참조하십시오.

Show/Hide Line Numbers (편집기 창 전용)

편집 창 왼쪽에 텍스트의 줄 번호를 표시하는 열을 엽니다. 기본 설정은 꺼져 있으며, 환경 설정에서 변경될 수 있습니다 (환경 설정을 참조하십시오).

Zoom/Restore Height

창을 보통 크기와 최대 높이 사이에서 전환합니다. IDLE 구성 대화 상자의 General 탭에서 변경하지 않는 한 초기 크기의 기본값은 40줄 80문자입니다. 화면의 최대 높이는 화면에서 처음 확대할 때 창을 일시적으로 최대화하여 결정됩니다. 화면 설정을 변경하면 저장된 높이가 무효가 될 수 있습니다. 이 전환은 창이 최대화되었을 때 적용되지 않습니다.

Window 메뉴 (셸과 편집기)

열려있는 모든 창의 이름을 나열합니다; 하나를 선택하여 전경으로 가져옵니다 (필요한 경우 아이콘화를 해제합니다).

Help 메뉴 (셸과 편집기)

About IDLE

버전, 저작권, 라이선스, 크레딧 등을 표시합니다.

IDLE Help

메뉴 옵션, 기본 편집과 탐색 및 기타 팁을 자세히 설명하는 이 IDLE 설명서를 표시합니다.

Python Docs

설치되었으면, 로컬 파이썬 문서에 액세스하거나, 웹 브라우저를 시작하여 최신 파이썬 설명서를 보여주는 docs.python.org 를 엽니다.

Turtle Demo

예제 파이썬 코드와 터틀 그래픽을 제공하는 turtledemo 모듈을 실행합니다.

IDLE 구성 대화 상자의 General 탭으로 여기에 도움말 소스를 추가할 수 있습니다. Help 메뉴 선택에 대한 자세한 내용은 아래의 도움말 소스 하위 섹션을 참조하십시오.

Context menus

윈도우에서 마우스 오른쪽 버튼을 클릭하여 문맥 메뉴를 엽니다 (macOS에서는 Control-클릭). 문맥 메뉴에는 Edit 메뉴에도 있는 표준 클립 보드 기능이 있습니다.

Cut

선택 사항을 시스템 전체 클립 보드에 복사합니다; 그런 다음 선택을 삭제합니다.

Copy

선택 사항을 시스템 전체 클립 보드에 복사합니다.

Paste

시스템 전체 클립 보드의 내용을 현재 창에 삽입합니다.

편집기 창에는 중단점 기능도 있습니다. 중단점이 설정된 줄은 특별히 표시됩니다. 중단점은 디버거에서 실행할 때만 영향을 미칩니다. 파일의 중단점은 사용자의 .idlerc 디렉터리에 저장됩니다.

Set Breakpoint

현재 줄에 중단점을 설정합니다.

Clear Breakpoint

해당 줄에서 중단점을 지웁니다.

셸과 출력 창에서는 다음과 같은 것도 있습니다.

Go to file/line

Debug 메뉴와 같습니다.

셸 창에는 아래 파이썬 셸 창 하위 섹션에 설명된 출력 압착 기능도 있습니다.

Squeeze

커서가 출력 줄 위에 있으면, 위 코드와 아래 프롬프트 사이의 모든 출력을 ‘Squeezed text’ 레이블로 압착합니다.

Editing and Navigation

편집기 창

설정과 IDLE 시작 방법에 따라, IDLE이 시작될 때 편집기 창을 열 수 있습니다. 그런 다음, File 메뉴를 사용하십시오. 주어진 파일에 대해 열린 편집기 창이 하나만 있을 수 있습니다.

제목 표시 줄에는 파일 이름, 전체 경로 및 창을 실행하는 파이썬과 IDLE 버전이 포함됩니다. 상태 표시 줄에는 줄 번호(‘Ln’)와 열 번호(‘Col’)가 있습니다. 줄 번호는 1로 시작합니다; 열 번호는 0으로 시작합니다.

IDLE은 알려진 .py* 확장자를 가진 파일에 파이썬 코드가 포함되어 있고 다른 파일은 그렇지 않다고 가정합니다. Run 메뉴를 사용하여 파이썬 코드를 실행하십시오.

키 바인딩

The IDLE insertion cursor is a thin vertical bar between character positions. When characters are entered, the insertion cursor and everything to its right moves right one character and the new character is entered in the new space.

Several non-character keys move the cursor and possibly delete characters. Deletion does not puts text on the clipboard, but IDLE has an undo list. Wherever this doc discusses keys, ‘C’ refers to the Control key on Windows and Unix and the Command key on macOS. (And all such discussions assume that the keys have not been re-bound to something else.)

Arrow keys move the cursor one character or line.

C-LeftArrow and C-RightArrow moves left or right one word.

Home and End go to the beginning or end of the line.

Page Up and Page Down go up or down one screen.

C-Home and C-End go to beginning or end of the file.

Backspace and Del (or C-d) delete the previous or next character.

C-Backspace and C-Del delete one word left or right.

C-k deletes (‘kills’) everything to the right.

(복사하는 C-c와 붙여넣기 하는 C-v와 같은) 표준 키 바인딩이 작동 할 수 있습니다. 키 바인딩은 IDLE 구성 대화 상자에서 선택됩니다.

자동 들여쓰기

블록을 여는 문장 다음에, 다음 줄은 4개의 스페이스로 들여쓰기 됩니다 (파이썬 셸 창에서는 한 탭씩). 특정 키워드(break, return 등)가 다음에 다음 줄이 내어 쓰기 됩니다. 앞선 들여쓰기에서, Backspace는 최대 4개의 스페이스가 있으면 삭제합니다. Tab은 스페이스를 삽입합니다 (파이썬 셸 창에서는 하나의 탭), 개수는 들여쓰기 너비에 따라 다릅니다. 현재 Tcl/Tk 제한으로 인해 탭은 4개의 스페이스로 제한됩니다.

Format 메뉴의 Indent/Dedent Region 명령도 참조하십시오.

Search and Replace

Any selection becomes a search target. However, only selections within a line work because searches are only performed within lines with the terminal newline removed. If [x] Regular expression is checked, the target is interpreted according to the Python re module.

완성

요청되고 사용할 수 있을 때, 모듈 이름, 클래스나 함수의 어트리뷰트 또는 파일명에 대한 완성(completions)이 제공됩니다. 각 요청 방법은 기존 이름을 가진 완성 상자가 표시됩니다. (예외는 아래의 탭 완성을 참조하십시오.) 모든 상자는, 문자를 입력하고 삭제해서; Up, Down, PageUp, PageDown, Home 및 End 키를 쳐서; 상자 안에서 한 번의 클릭으로 완성 중인 이름과 상자에서 강조 표시된 항목을 변경합니다. Escape, Enter 및 이중 Tab 키나 상자 외부를 클릭하여 상자를 닫으십시오. 상자 안에서 더블 클릭하면 선택하고 닫습니다.

상자를 여는 한 가지 방법은 키 문자를 입력하고 미리 정의된 간격만큼 기다리는 것입니다. 기본값은 2초입니다; 설정 대화 상자에서 사용자 정의하십시오. (자동 팝업을 방지하려면, 지연을 100000000과 같은 큰 밀리초로 설정하십시오.) 임포트한 모듈 이름이나 클래스나 함수 어트리뷰트의 경우, ‘.’를 입력하십시오. 루트 디렉터리의 파일명은 여는 인용 부호 바로 뒤에 os.sep이나 os.altsep을 입력하십시오. (윈도우에서는, 먼저 드라이브를 지정할 수 있습니다.) 디렉터리 이름과 구분자를 입력하여 서브 디렉터리로 이동하십시오.

기다리는 대신, 또는 상자를 닫은 후, Edit 메뉴에서 Show Completions를 사용하여 즉시 완성 상자를 여십시오. 기본 단축키는 C-space입니다. 상자를 열기 전에 원하는 이름의 접두사를 입력하면, 첫 번째 일치나 근거리 불일치가 표시됩니다. 결과는 상자가 표시된 후 접두사를 입력하는 것과 같습니다. 따옴표 뒤에서의 Show Completions는 루트 디렉터리 대신 현재 디렉터리에서 파일명을 완성합니다.

접두사 다음에 Tab을 누르면 일반적으로 Show Completions와 같은 효과가 있습니다. (접두사가 없으면 들여쓰기합니다.) 그러나, 접두사와 일치하는 항목이 하나뿐이면, 상자를 열지 않고 해당 일치가 편집기 텍스트에 즉시 추가됩니다.

문자열 밖에서 선행 ‘.’ 없이 접두어 뒤에서 ‘Show Completions’를 실행하거나 Tab을 누르면 키워드, 내장 이름 및 사용 가능한 모듈 수준 이름이 포함된 상자를 엽니다.

(셸과 달리) 편집기에서 코드를 편집할 때는, 셸을 다시 시작하지 않고 코드를 실행해서 사용 가능한 모듈 수준 이름을 늘리십시오. 파일 맨 위에 임포트를 추가한 후에 특히 유용합니다. 이것은 또한 가능한 어트리뷰트 완성을 늘립니다.

Completion boxes initially exclude names beginning with ‘_’ or, for modules, not included in ‘__all__’. The hidden names can be accessed by typing ‘_’ after ‘.’, either before or after the box is opened.

콜팁

액세스할 수 있는 함수 이름 다음에 (를 입력하면 콜팁이 자동으로 표시됩니다. 함수 이름 표현식에는 점과 서브스크립트가 포함될 수 있습니다. 콜팁은 클릭하거나, 커서가 인자 영역 밖으로 이동하거나, )를 입력할 때까지 남아 있습니다. 커서가 정의의 인자 부분에 있을 때마다, 콜팁을 표시하려면 메뉴에서 Edit와 “Show Call Tip”을 선택하거나 바로 가기를 입력하십시오.

콜팁은 함수 서명과 독스트링의 첫 번째 빈 줄이나 다섯 번째 비어 있지 않은 줄에 이르는 줄로 구성됩니다. (일부 내장 함수에는 액세스할 수 있는 서명이 없습니다.) 서명의 ‘/’나 ‘*’는 앞서거나 뒤따르는 인자가 위치나 이름(키워드) 전용으로 전달됨을 가리킵니다. 세부 사항은 변경될 수 있습니다.

셸에서, 액세스할 수 있는 함수는 Idle 스스로 임포트 한 모듈을 포함하여, 사용자 프로세스로 임포트 한 모듈과 마지막 재시작 이후에 어떤 정의가 실행되었는지에 따라 다릅니다.

예를 들어, 셸을 다시 시작하고 itertools.count(를 입력하십시오. Idle이 자신의 목적으로 itertools를 사용자 프로세스로 임포트 하기 때문에 콜팁이 표시됩니다. (이것은 변경될 수 있습니다.) turtle.write(를 입력하면 아무것도 나타나지 않습니다. Idle은 직접 turtle을 임포트 하지 않습니다. 메뉴 항목과 바로 가기도 아무것도 하지 않습니다. import turtle을 입력하십시오. 그다음부터, turtle.write(가 콜팁을 표시합니다.

편집기에서, import 문은 파일을 실행할 때까지 효과가 없습니다. import 문을 작성한 후, 함수 정의를 추가한 후 또는 기존 파일을 연 후 파일을 실행하고 싶을 것입니다.

코드 컨텍스트

파이썬 코드가 포함된 편집기 창 내에서, 창의 상단에 팬을 표시하거나 숨기기 위해 코드 컨텍스트를 토글 할 수 있습니다. 표시될 때, 이 분할 창은 class, def 또는 if 키워드로 시작하는 것과 같이 블록 코드를 여는 줄들을 고정합니다, 그렇지 않다면 뷰에서 스크롤 되어 빠져나갈 줄들입니다. 팬의 크기는 모든 현재 컨텍스트 수준을 표시하기 위해 필요에 따라 확장과 축소되며, IDLE 구성 대화 상자에 정의된 최대 줄 수가지 입니다 (기본값은 15). 현재 컨텍스트 줄이 없고 기능이 켜지면, 빈 줄 하나가 표시됩니다. 컨텍스트 팬에서 줄을 클릭하면 해당 줄을 편집기 맨 위로 이동합니다.

컨텍스트 팬의 텍스트와 배경색은 IDLE 구성 대화 상자의 Highlights 탭에서 구성할 수 있습니다.

Shell window

In IDLE’s Shell, enter, edit, and recall complete statements. (Most consoles and terminals only work with a single physical line at a time).

Submit a single-line statement for execution by hitting Return with the cursor anywhere on the line. If a line is extended with Backslash (\), the cursor must be on the last physical line. Submit a multi-line compound statement by entering a blank line after the statement.

When one pastes code into Shell, it is not compiled and possibly executed until one hits Return, as specified above. One may edit pasted code first. If one pastes more than one statement into Shell, the result will be a SyntaxError when multiple statements are compiled as if they were one.

Lines containing RESTART mean that the user execution process has been re-started. This occurs when the user execution process has crashed, when one requests a restart on the Shell menu, or when one runs code in an editor window.

The editing features described in previous subsections work when entering code interactively. IDLE’s Shell window also responds to the following:

C-c attempts to interrupt statement execution (but may fail).

C-d closes Shell if typed at a >>> prompt.

Alt-p and Alt-n (C-p and C-n on macOS) retrieve to the current prompt the previous or next previously entered statement that matches anything already typed.

Return while the cursor is on any previous statement appends the latter to anything already typed at the prompt.

텍스트 색상

Idle은 기본적으로 흰색 위의 검은색 텍스트지만, 특수한 의미로 텍스트를 채색합니다. 셸의 경우, 셸 출력, 셸 에러, 사용자 출력 및 사용자 에러입니다. 파이썬 코드의 경우, 셸 프롬프트나 편집기에서, 키워드, 내장 클래스와 함수 이름, class와 def 뒤에 오는 이름, 문자열 및 주석입니다. 모든 텍스트 창에서, 커서 (있다면), 찾은 텍스트 (가능하다면) 및 선택한 텍스트입니다.

IDLE also highlights the soft keywords match, case, and _ in pattern-matching statements. However, this highlighting is not perfect and will be incorrect in some rare cases, including some _-s in case patterns.

텍스트 채색은 백그라운드에서 수행되므로, 채색되지 않은 텍스트가 때때로 표시됩니다. 색 구성표를 변경하려면, IDLE 구성 대화 상자 Highlighting 탭을 사용하십시오. 편집기의 디버거 중단점 표시와 팝업과 대화 상자의 텍스트는 사용자가 구성할 수 없습니다.

Startup and Code Execution

-s 옵션으로 시작할 때, IDLE은 환경 변수 IDLESTARTUP이나 PYTHONSTARTUP가 참조하는 파일을 실행합니다. IDLE은 먼저 IDLESTARTUP을 확인합니다; IDLESTARTUP이 있으면 참조된 파일이 실행됩니다. IDLESTARTUP이 없으면, IDLE은 PYTHONSTARTUP을 확인합니다. 이러한 환경 변수가 참조하는 파일은 IDLE 셸에서 자주 사용되는 함수를 저장하거나 공통 모듈을 임포트 하기 위해 import 문을 실행하기에 편리한 장소입니다.

또한, Tk도 시작 파일이 있으면 로드합니다. Tk 파일은 무조건 로드됨에 유의하십시오. 이 추가 파일은 .Idle.py이며 사용자의 홈 디렉터리에서 찾습니다. 이 파일의 문장은 Tk 이름 공간에서 실행되므로, 이 파일은 IDLE의 파이썬 셸에서 사용할 함수를 임포트 하는 데 유용하지 않습니다.

명령 줄 사용법

idle.py [-c command] [-d] [-e] [-h] [-i] [-r file] [-s] [-t title] [-] [arg] ...

-c command  run command in the shell window
-d          enable debugger and open shell window
-e          open editor window
-h          print help message with legal combinations and exit
-i          open shell window
-r file     run file in shell window
-s          run $IDLESTARTUP or $PYTHONSTARTUP first, in shell window
-t title    set title of shell window
-           run stdin in shell (- must be last option before args)

인자가 있으면:

-, -c 또는 r이 사용되면, 모든 인자는 sys.argv[1:...]에 배치되고 sys.argv[0]은 '', '-c' 또는 '-r'로 설정됩니다. Options 대화 상자에서 기본값이 설정되어 있어도, 편집기 창이 열리지 않습니다.

그렇지 않으면, 인자는 편집을 위해 열리는 파일이며 sys.argv는 IDLE 자체에 전달된 인자를 반영합니다.

시작 실패

IDLE은 소켓을 사용하여 IDLE GUI 프로세스와 사용자 코드 실행 프로세스 간에 통신합니다. 셸을 시작하거나 다시 시작할 때마다 연결을 만들어야 합니다. (후자는 ‘RESTART’라고 표시된 구분 선으로 표시됩니다). 사용자 프로세스가 GUI 프로세스에 연결하지 못하면, 보통 사용자에게 알리는 ‘cannot connect’ 메시지가 담긴 Tk 에러 상자가 표시됩니다. 그런 다음 종료합니다.

유닉스 시스템의 한가지 특정한 연결 실패는 시스템 네트워크 설정의 어딘가에서 잘못 구성된 마스쿼레이딩 규칙으로 인해 발생합니다. IDLE이 터미널에서 시작될 때, ** Invalid host:로 시작하는 메시지를 보게 됩니다. 유효한 값은 127.0.0.1 (idlelib.rpc.LOCALHOST)입니다. 한 터미널 창에서 tcpconnect -irv 127.0.0.1 6543로, 다른 창에서 tcplisten <same args>로 진단할 수 있습니다.

일반적인 실패 원인은 random.py와 tkinter.py처럼, 표준 라이브러리 모듈과 이름이 같은 사용자가 작성한 파일입니다. 이러한 파일이 실행하려는 파일과 같은 디렉터리에 있을 때, IDLE은 표준 라이브러리 파일을 임포트 할 수 없습니다. 현재 수선법은 사용자 파일의 이름을 바꾸는 것입니다.

앞엣것보다 덜 흔하지만, 바이러스 백신이나 방화벽 프로그램이 연결을 중지할 수 있습니다. 프로그램이 연결을 허용하도록 지시할 수 없으면, IDLE이 작동하도록 프로그램을 꺼야 합니다. 외부 포트에 데이터가 노출되지 않기 때문에 이 내부 연결을 허용하는 것은 안전합니다. 비슷한 문제는 연결을 차단하는 네트워크 구성 에러입니다.

파이썬 설치 문제로 인해 IDLE이 중지되는 경우가 있습니다: 여러 버전이 충돌하거나 단일 설치에 관리자 액세스가 필요할 수 있습니다. 충돌을 제거하거나, 관리자 권한으로 실행할 수 없거나 그러고 싶지 않으면 파이썬을 완전히 제거하고 다시 시작하기가 가장 쉽습니다.

좀비 pythonw.exe 프로세스가 문제일 수 있습니다. 윈도우에서는, 작업 관리자를 사용하여 확인하고 있다면 중지하십시오. 때때로 프로그램 충돌이나 키보드 인터럽트(control-C)에 의해 시작된 재시작이 연결에 실패할 수 있습니다. 에러 상자를 닫거나 Shell 메뉴에서 Restart Shell을 사용하면 일시적인 문제를 해결할 수 있습니다.

IDLE이 처음 시작되면, ~/.idlerc/에서 사용자 구성 파일을 읽으려고 시도합니다 (~는 사용자의 홈 디렉터리입니다). 문제가 있으면, 에러 메시지가 표시되어야 합니다. 임의의 디스크 결함은 예외로 할 때, 파일을 절대 직접 편집하지 않으면 이를 방지할 수 있습니다. 대신, Options의 구성 대화 상자를 사용하십시오. 일단 사용자 구성 파일에 에러가 발생하면, 이를 삭제하고 설정 대화 상자에서 다시 시작하는 것이 가장 좋습니다.

IDLE이 메시지 없이 종료되고, 콘솔에서 시작되지 않았으면, 콘솔이나 터미널에서 시작하고 (python -m idlelib) 에러 메시지가 나타나는지 확인하십시오.

Tcl/tk가 8.6.11(About IDLE을 보십시오)보다 오래된 유닉스 기반 시스템에서 특정 글꼴의 특정 문자는 터미널에 보내는 메시지와 함께 tk 실패를 일으킬 수 있습니다. 이러한 문자가 있는 파일을 편집하기 위해 IDLE을 시작하거나 나중에 이러한 문자를 입력할 때 발생할 수 있습니다. tcl/tk를 업그레이드할 수 없으면, 더 잘 작동하는 글꼴을 사용하도록 IDLE을 다시 구성하십시오.

사용자 코드 실행하기

With rare exceptions, the result of executing Python code with IDLE is intended to be the same as executing the same code by the default method, directly with Python in a text-mode system console or terminal window. However, the different interface and operation occasionally affect visible results. For instance, sys.modules starts with more entries, and threading.active_count() returns 2 instead of 1.

기본적으로, IDLE은 셸과 편집기를 실행하는 사용자 인터페이스 프로세스가 아닌 별도의 OS 프로세스에서 사용자 코드를 실행합니다. 실행 프로세스에서, sys.stdin, sys.stdout 및 sys.stderr를 셸 창에서 입력을 받고 셸 창으로 출력을 보내는 객체로 바꿉니다. sys.__stdin__, sys.__stdout__ 및 sys.__stderr__에 저장된 원래 값은 건드리지 않지만, None일 수 있습니다.

한 프로세스에서 다른 프로세스의 텍스트 위젯으로 인쇄 출력을 보내는 것은 같은 프로세스에서 시스템 터미널로 인쇄하는 것보다 느립니다. 이것은 여러 인자를 인쇄할 때 특히 그렇습니다. 각 인자의 문자열, 각 구분자, 줄 바꿈은 개별적으로 전송되기 때문입니다. 개발할 때는 일반적으로 문제가 되지 않지만, IDLE로 더 빨리 인쇄하려면 표시하려는 모든 항목을 포맷하고 결합한 다음 단일 문자열을 인쇄하십시오. 포맷 문자열과 str.join() 모두 필드와 줄을 결합하는 데 도움이 될 수 있습니다.

IDLE’s standard stream replacements are not inherited by subprocesses created in the execution process, whether directly by user code or by modules such as multiprocessing. If such subprocess use input from sys.stdin or print or write to sys.stdout or sys.stderr, IDLE should be started in a command line window. (On Windows, use python or py rather than pythonw or pyw.) The secondary subprocess will then be attached to that window for input and output.

importlib.reload(sys)와 같은 사용자 코드에 의해 sys가 재설정되면, IDLE의 변경 사항이 손실되고 키보드로부터의 입력과 화면으로의 출력이 올바르게 동작하지 않게 됩니다.

셸에 포커스가 있으면, 키보드와 화면을 제어합니다. 이것은 일반적으로 투명하지만, 키보드와 화면에 직접 액세스하는 함수는 작동하지 않습니다. 여기에는 키를 눌렀는지를 판단하는 시스템 특정 함수가 포함됩니다.

실행 프로세스에서 실행 중인 IDLE 코드는 그렇지 않다면 없을 프레임을 호출 스택에 추가합니다. IDLE은 sys.getrecursionlimit와 sys.setrecursionlimit를 래핑하여 추가 스택 프레임의 영향을 줄입니다.

사용자 코드가 직접 또는 sys.exit를 호출하여 SystemExit를 발생시키면, IDLE은 종료하는 대신 셸 프롬프트로 돌아갑니다.

셸의 사용자 출력

프로그램이 텍스트를 출력할 때, 결과는 해당 출력 장치에 의해 결정됩니다. IDLE이 사용자 코드를 실행할 때, sys.stdout과 sys.stderr이 IDLE 셸의 표시 영역에 연결됩니다. 그 기능 중 일부는 하부 Tk Text 위젯에서 상속됩니다. 다른 것은 프로그래밍한 추가 사항입니다. (중요하다면) 셸은 상용 실행보다는 개발용으로 설계되었습니다.

예를 들어, 셸은 절대로 출력을 버리지 않습니다. 셸에 무제한 출력을 보내는 프로그램은 결국 메모리를 채워서, 메모리 에러를 일으킵니다. 반대로, 일부 시스템 텍스트 창은 마지막 n 줄의 출력만 유지합니다. 예를 들어, 윈도우 콘솔은 사용자가 설정하면 최대 9999줄을 유지할 수 있으며, 기본값은 300입니다.

Tk Text 위젯, 따라서 IDLE의 셸은 유니코드의 BMP (Basic Multilingual Plane) 부분 집합에서 문자(코드 포인트)를 표시합니다. 어떤 문자가 적절한 글리프로 표시될지와 어떤 문자가 대체 상자로 표시될지는 운영 체제와 설치된 글꼴에 따라 다릅니다. 탭 문자는 뒤따르는 문자가 다음 탭 정지 뒤에서 시작되도록 합니다. (탭 정지는 8 ‘문자’마다 나타납니다). 줄 바꿈 문자는 뒤따르는 텍스트가 새 줄에 나타나게 합니다. 다른 제어 문자는 운영 체제와 글꼴에 따라 무시되거나 스페이스, 상자 또는 그 밖의 것으로 표시됩니다. (화살표 키를 사용하여 이러한 출력에서 텍스트 커서를 움직이면 예상치 못한 간격 동작이 나타날 수 있습니다.)

>>> s = 'a\tb\a<\x02><\r>\bc\nd'  # Enter 22 chars.
>>> len(s)
14
>>> s  # Display repr(s)
'a\tb\x07<\x02><\r>\x08c\nd'
>>> print(s, end='')  # Display s as is.
# Result varies by OS and font.  Try it.

repr 함수는 표현식 값의 대화 형 에코에 사용됩니다. 입력 문자열의 변경된 버전을 반환하는데, 제어 코드, 일부 BMP 코드 포인트 및 모든 BMP 이외의 코드 포인트가 이스케이프 코드로 대체됩니다. 위에서 예시했듯이, 어떻게 표시되는지와 관계없이 문자열의 문자를 식별할 수 있도록 합니다.

정상과 에러 출력은 일반적으로 코드 입력 및 서로와 분리되어 별도의 줄에 유지됩니다. 그들은 각각 다른 강조 색상을 얻습니다.

SyntaxError 트레이스백의 경우, 에러가 감지된 곳의 일반적인 ‘^’ 표시는 에러 강조로 텍스트를 색칠하는 것으로 대체됩니다. 파일에서 실행한 코드가 다른 예외를 발생시킬 때, 트레이스백 줄을 마우스 오른쪽 단추로 클릭하여 IDLE 편집기의 해당 줄로 이동할 수 있습니다. 필요하면 파일이 열립니다.

셸에는 출력 라인을 ‘Squeezed text’ 레이블로 압착하는 특수 기능이 있습니다. 이것은 N 줄을 넘어가는 출력에 대해 자동으로 수행됩니다 (기본적으로 N = 50). Settings 대화 상자의 General 페이지의 PyShell 섹션에서 N을 변경할 수 있습니다. 출력을 마우스 오른쪽 버튼으로 클릭하면 더 적은 줄의 출력을 압착할 수 있습니다. 이것은 스크롤 속도를 늦출 수 있을 정도로 긴 줄에 유용할 수 있습니다.

압착된 출력은 레이블을 더블 클릭하여 제자리에서 펼쳐집니다. 레이블을 마우스 오른쪽 버튼으로 클릭하여 클립 보드나 별도의 보기 창으로 보낼 수도 있습니다.

tkinter 응용 프로그램 개발하기

IDLE은 tkinter 프로그램 개발을 용이하게 하기 위해 표준 파이썬과 의도적으로 다릅니다. 표준 파이썬에서 import tkinter as tk; root = tk.Tk()를 입력하면 아무것도 나타나지 않습니다. IDLE에 동일하게 입력하면 tk 창이 나타납니다. 표준 파이썬에서는, 창을 보려면 root.update()도 입력해야 합니다. IDLE은 초당 약 20회, 대략 50밀리초마다, 백그라운드에서 동등한 일을 합니다. 그런 다음 b = tk.Button(root, text='button'); b.pack()을 입력하십시오. 마찬가지로, 표준 파이썬에서는 root.update()를 입력할 때까지 아무것도 시각적으로 변경되지 않습니다.

대부분의 tkinter 프로그램은 root.mainloop()를 실행하는데, 일반적으로 tk 앱이 파괴될 때까지 반환되지 않습니다. 프로그램이 python -i이나 IDLE 편집기에서 실행되면, mainloop()가 반환할 때까지 (상호 작용할 것이 남아있지 않을 때까지) >>> 셸 프롬프트가 나타나지 않습니다.

IDLE 편집기에서 tkinter 프로그램을 실행할 때, mainloop 호출을 주석 처리할 수 있습니다. 그러면 즉시 셸 프롬프트를 얻고 라이브 응용 프로그램과 상호 작용할 수 있습니다. 표준 파이썬에서 실행할 때 mainloop 호출을 다시 활성화해야 한다는 것을 기억해야 합니다.

서브 프로세스 없이 실행하기

By default, IDLE executes user code in a separate subprocess via a socket, which uses the internal loopback interface. This connection is not externally visible and no data is sent to or received from the internet. If firewall software complains anyway, you can ignore it.

소켓 연결 시도가 실패하면, Idle은 여러분에게 알립니다. 이러한 장애는 때때로 일시적이지만, 지속한다면, 문제는 방화벽이 연결을 차단하거나 특정 시스템의 구성이 잘못되었을 수 있습니다. 문제가 해결될 때까지, -n 명령 줄 스위치를 사용하여 Idle을 실행할 수 있습니다.

IDLE이 -n 명령 줄 스위치로 시작되면 단일 프로세스에서 실행되며 RPC 파이썬 실행 서버를 실행하는 서브 프로세스를 만들지 않습니다. 파이썬이 플랫폼에서 서브 프로세스나 RPC 소켓 인터페이스를 만들 수 없을 때 유용할 수 있습니다. 그러나, 이 모드에서 사용자 코드는 IDLE 자체와 분리되지 않습니다. 또한, Run/Run Module (F5) 가 선택될 때 환경이 다시 시작되지 않습니다. 코드가 수정되면, 변경 사항을 적용하려면 영향을 받는 모듈을 reload()하고 특정 항목을 다시 임포트 해야 합니다 (예를 들어 from foo import baz). 이러한 이유로, 가능하다면 기본 서브 프로세스로 IDLE을 실행하는 것이 좋습니다.

버전 3.4부터 폐지됨.

Help and Preferences

도움말 소스

Help 메뉴 항목 “IDLE Help”는 라이브러리 레퍼런스의 IDLE 장의 포맷된 html 버전을 표시합니다. 읽기 전용 tkinter 텍스트 창에 표시되는 결과는 웹 브라우저에서 보는 것과 비슷합니다. 마우스 휠, 스크롤 바 또는 위/아래 화살표 키를 누른 상태로 텍스트를 탐색하십시오. 또는 TOC(목차) 단추를 클릭하고 열린 상자에서 섹션 머리글을 선택하십시오.

Help 메뉴 항목 “Python Docs”는 docs.python.org/x.y에 있는 자습서를 포함하여 광범위한 도움말 소스를 엽니다, 여기서 ‘x.y’는 현재 실행 중인 파이썬 버전입니다. 시스템에 문서의 오프라인 사본이 있으면 (설치 옵션일 수 있습니다), 대신 열립니다.

IDLE 구성 대화 상자의 General 탭을 사용하여 언제든지 도움말 메뉴에서 선택한 URL을 추가하거나 제거할 수 있습니다.

환경 설정

글꼴 설정, 강조 표시, 키 및 일반 설정은 Option 메뉴의 IDLE 구성을 통해 변경할 수 있습니다. 기본이 아닌 사용자 설정은 사용자 홈 디렉터리의 .idlerc 디렉터리에 저장됩니다. 잘못된 사용자 구성 파일로 인한 문제점은 .idlerc에서 하나 이상의 파일을 편집하거나 삭제하여 해결됩니다.

Font 탭에서, 여러 언어로 된 여러 문자의 서체와 크기 효과에 대한 텍스트 샘플을 참조하십시오. 개인적으로 관심 있는 다른 문자를 추가하려면 샘플을 편집하십시오. 샘플을 사용하여 고정 폭 글꼴을 선택하십시오. 셸이나 편집기에서 특정 문자에 문제가 있으면, 샘플 상단에 해당 문자를 추가하고 먼저 크기를 변경한 다음 글꼴을 변경해보십시오.

Highlights와 Keys 탭에서, 내장이나 사용자 정의 색상 테마와 키 집합을 선택하십시오. 이전 IDLE로 최신 내장 색상 테마나 키 집합을 사용하려면, 새 사용자 정의 색상 테마나 키 집합으로 저장하십시오, 그러면 이전 IDLE에서 쉽게 액세스 할 수 있습니다.

macOS의 IDLE

시스템 환경설정: Dock에서, “문서를 열 때 탭 사용”을 “항상”으로 설정할 수 있습니다. 이 설정은 IDLE에서 사용하는 tk/tkinter GUI 프레임 워크와 호환되지 않으며, 몇 가지 IDLE 기능을 훼손합니다.

확장

IDLE에는 확장 기능이 포함되어 있습니다. 설정 대화 상자의 Extensions 탭에서 확장에 대한 설정을 변경할 수 있습니다. 자세한 정보는 idlelib 디렉터리에 있는 config-extensions.def의 시작 부분을 참조하십시오. 현재 기본 확장은 zzdummy 뿐이며, 테스트에도 사용되는 예입니다.

idlelib

Source code: Lib/idlelib [https://github.com/python/cpython/tree/main/Lib/idlelib]

The Lib/idlelib package implements the IDLE application. See the rest of this page for how to use IDLE.

The files in idlelib are described in idlelib/README.txt. Access it either in idlelib or click Help => About IDLE on the IDLE menu. This file also maps IDLE menu items to the code that implements the item. Except for files listed under ‘Startup’, the idlelib code is ‘private’ in sense that feature changes can be backported (see PEP 434 [https://peps.python.org/pep-0434/]).

개발 도구

The modules described in this chapter help you write software. For example, the pydoc module takes a module and generates documentation based on the module’s contents. The doctest and unittest modules contains frameworks for writing unit tests that automatically exercise code and verify that the expected output is produced.

이 장에서 설명하는 모듈 목록은 다음과 같습니다:

typing — 형 힌트 지원

Specification for the Python Type System

형 에일리어스

NewType

Annotating callable objects

제네릭

Annotating tuples

The type of class objects

Annotating generators and coroutines

사용자 정의 제네릭 형

Any 형

명목적 대 구조적 서브 타이핑

모듈 내용

특수 타이핑 프리미티브

특수형

Any

AnyStr

LiteralString

Never

NoReturn

Self

TypeAlias

특수 형태

Union

Optional

Concatenate

Literal

ClassVar

Final

Required

NotRequired

ReadOnly

Annotated

TypeIs

TypeGuard

Unpack

Building generic types and type aliases

Generic

TypeVar

__name__

__covariant__

__contravariant__

__infer_variance__

__bound__

evaluate_bound()

__constraints__

evaluate_constraints()

__default__

evaluate_default()

has_default()

TypeVarTuple

__name__

__default__

evaluate_default()

has_default()

ParamSpec

args

kwargs

__name__

__default__

evaluate_default()

has_default()

ParamSpecArgs

ParamSpecKwargs

TypeAliasType

__name__

__module__

__type_params__

__value__

evaluate_value()

기타 특수 지시자

NamedTuple

NewType

__module__

__name__

__supertype__

Protocol

runtime_checkable()

TypedDict

__total__

__required_keys__

__optional_keys__

__readonly_keys__

__mutable_keys__

프로토콜

SupportsAbs

SupportsBytes

SupportsComplex

SupportsFloat

SupportsIndex

SupportsInt

SupportsRound

ABCs for working with IO

IO

TextIO

BinaryIO

함수와 데코레이터

cast()

assert_type()

assert_never()

reveal_type()

dataclass_transform()

overload()

get_overloads()

clear_overloads()

final()

no_type_check()

no_type_check_decorator()

override()

type_check_only()

인트로스펙션 도우미

get_type_hints()

get_origin()

get_args()

get_protocol_members()

is_protocol()

is_typeddict()

ForwardRef

evaluate_forward_ref()

NoDefault

상수

TYPE_CHECKING

Deprecated aliases

Aliases to built-in types

Dict

List

Set

FrozenSet

Tuple

Type

Aliases to types in collections

DefaultDict

OrderedDict

ChainMap

Counter

Deque

Aliases to other concrete types

Pattern

Match

Text

Aliases to container ABCs in collections.abc

AbstractSet

Collection

Container

ItemsView

KeysView

Mapping

MappingView

MutableMapping

MutableSequence

MutableSet

Sequence

ValuesView

Aliases to asynchronous ABCs in collections.abc

Coroutine

AsyncGenerator

AsyncIterable

AsyncIterator

Awaitable

Aliases to other ABCs in collections.abc

Iterable

Iterator

Callable

Generator

Hashable

Reversible

Sized

Aliases to contextlib ABCs

ContextManager

AsyncContextManager

Deprecation Timeline of Major Features

pydoc — Documentation generator and online help system

파이썬 개발 모드

파이썬 개발 모드의 효과

ResourceWarning 예

잘못된 파일 기술자 에러 예

doctest — Test interactive Python examples

간단한 사용법: 독스트링에 있는 예제 확인하기

간단한 사용법: 텍스트 파일에 있는 예제 확인하기

작동 방법

어떤 독스트링을 검사합니까?

독스트링 예제는 어떻게 인식됩니까?

실행 컨텍스트란 무엇입니까?

예외는 어떻게 됩니까?

옵션 플래그

DONT_ACCEPT_TRUE_FOR_1

DONT_ACCEPT_BLANKLINE

NORMALIZE_WHITESPACE

ELLIPSIS

IGNORE_EXCEPTION_DETAIL

SKIP

COMPARISON_FLAGS

REPORT_UDIFF

REPORT_CDIFF

REPORT_NDIFF

REPORT_ONLY_FIRST_FAILURE

FAIL_FAST

REPORTING_FLAGS

register_optionflag()

지시자

경고

기본 API

testfile()

testmod()

run_docstring_examples()

Unittest API

DocFileSuite()

DocTestSuite()

failureException

set_unittest_reportflags()

고급 API

DocTest 객체

DocTest

examples

globs

name

filename

lineno

docstring

Example 객체

Example

source

want

exc_msg

lineno

indent

options

DocTestFinder 객체

DocTestFinder

find()

DocTestParser 객체

DocTestParser

get_doctest()

get_examples()

parse()

TestResults objects

TestResults

failed

attempted

skipped

DocTestRunner 객체

DocTestRunner

report_start()

report_success()

report_failure()

report_unexpected_exception()

run()

summarize()

tries

failures

skips

OutputChecker 객체

OutputChecker

check_output()

output_difference()

디버깅

script_from_examples()

testsource()

debug()

debug_src()

DebugRunner

DocTestFailure

test

example

got

UnexpectedException

test

example

exc_info

맺음말

unittest — Unit testing framework

기본 예시

명령행 인터페이스

명령행 옵션

테스트 탐색(Discovery)

테스트 코드 구조 잡기

이전의 테스트 코드를 다시 사용하기

테스트 건너뛰기와 예상된 실패

skip()

skipIf()

skipUnless()

expectedFailure()

SkipTest

부분 테스트(subtest)를 사용하여 테스트 반복 구별 짓기

클래스와 함수

테스트 케이스

TestCase

setUp()

tearDown()

setUpClass()

tearDownClass()

run()

skipTest()

subTest()

debug()

assertEqual()

assertNotEqual()

assertTrue()

assertFalse()

assertIs()

assertIsNot()

assertIsNone()

assertIsNotNone()

assertIn()

assertNotIn()

assertIsInstance()

assertNotIsInstance()

assertRaises()

assertRaisesRegex()

assertWarns()

assertWarnsRegex()

assertLogs()

records

output

assertNoLogs()

assertAlmostEqual()

assertNotAlmostEqual()

assertGreater()

assertGreaterEqual()

assertLess()

assertLessEqual()

assertRegex()

assertNotRegex()

assertCountEqual()

addTypeEqualityFunc()

assertMultiLineEqual()

assertSequenceEqual()

assertListEqual()

assertTupleEqual()

assertSetEqual()

assertDictEqual()

fail()

failureException

longMessage

maxDiff

countTestCases()

defaultTestResult()

id()

shortDescription()

addCleanup()

enterContext()

doCleanups()

addClassCleanup()

enterClassContext()

doClassCleanups()

IsolatedAsyncioTestCase

loop_factory

asyncSetUp()

asyncTearDown()

addAsyncCleanup()

enterAsyncContext()

run()

FunctionTestCase

테스트 분류

TestSuite

addTest()

addTests()

run()

debug()

countTestCases()

__iter__()

테스트를 로드하고 실행하기

TestLoader

errors

loadTestsFromTestCase()

loadTestsFromModule()

loadTestsFromName()

loadTestsFromNames()

getTestCaseNames()

discover()

testMethodPrefix

sortTestMethodsUsing

suiteClass

testNamePatterns

TestResult

errors

failures

skipped

expectedFailures

unexpectedSuccesses

collectedDurations

shouldStop

testsRun

buffer

failfast

tb_locals

wasSuccessful()

stop()

startTest()

stopTest()

startTestRun()

stopTestRun()

addError()

addFailure()

addSuccess()

addSkip()

addExpectedFailure()

addUnexpectedSuccess()

addSubTest()

addDuration()

TextTestResult

defaultTestLoader

TextTestRunner

_makeResult()

run()

main()

load_tests 프로토콜

클래스와 모듈 픽스쳐

setUpClass 와 tearDownClass

setUpModule 과 tearDownModule

addModuleCleanup()

enterModuleContext()

doModuleCleanups()

시그널 처리하기

installHandler()

registerResult()

removeResult()

removeHandler()

unittest.mock — mock object library

간략 지침

Mock 클래스

Mock

assert_called()

assert_called_once()

assert_called_with()

assert_called_once_with()

assert_any_call()

assert_has_calls()

assert_not_called()

reset_mock()

mock_add_spec()

attach_mock()

configure_mock()

__dir__()

_get_child_mock()

called

call_count

return_value

side_effect

call_args

call_args_list

method_calls

mock_calls

__class__

NonCallableMock

PropertyMock

AsyncMock

assert_awaited()

assert_awaited_once()

assert_awaited_with()

assert_awaited_once_with()

assert_any_await()

assert_has_awaits()

assert_not_awaited()

reset_mock()

await_count

await_args

await_args_list

ThreadingMock

wait_until_called()

wait_until_any_call_with()

DEFAULT_TIMEOUT

호출

어트리뷰트 삭제

모의 객체 이름과 이름 어트리뷰트

모의 객체를 어트리뷰트로 연결하기

패처

patch

patch()

patch.object

object()

patch.dict

dict()

patch.multiple

multiple()

패처 메서드: start와 stop

stopall()

내장 패치

TEST_PREFIX

패치 데코레이터 중첩하기

패치할 곳

디스크립터와 프락시 객체 패치하기

MagicMock과 매직 메서드 지원

매직 메서드 모킹하기

매직 모의 객체

MagicMock

NonCallableMagicMock

도우미

sentinel

sentinel

DEFAULT

DEFAULT

call

call()

call_list()

create_autospec

create_autospec()

ANY

ANY

FILTER_DIR

FILTER_DIR

mock_open

mock_open()

자동 사양

실링 모의 객체 봉인하기

seal()

Order of precedence of side_effect, return_value and wraps

unittest.mock — getting started

모의 객체 사용하기

메서드를 패치하는 모의 객체

객체의 메서드 호출을 위한 모의 객체

클래스 모킹하기

모의 객체 이름 붙이기

모든 호출 추적하기

반환 값과 어트리뷰트 설정하기

모의 객체로 예외 발생시키기

부작용 함수와 이터러블

비동기 이터레이터 모킹하기

비동기 컨텍스트 관리자 모킹하기

기존 객체에서 모의 객체 만들기

Using side_effect to return per file content

패치 데코레이터

추가 예

연쇄 호출 모킹하기

부분 모킹

제너레이터 메서드 모킹하기

모든 테스트 메서드에 같은 패치 적용하기

연결되지 않은 메서드 모킹하기

모의 객체로 여러 호출 확인하기

가변 인자에 대처하기

중첩 패치

MagicMock으로 딕셔너리 모킹하기

Mock 서브 클래스와 그 어트리뷰트

patch.dict로 임포트를 모킹하기

호출 순서 추적과 덜 상세한 호출 어서션

더 복잡한 인자 일치

test — Regression tests package for Python

test 패키지를 위한 단위 테스트 작성하기

명령 줄 인터페이스를 사용하여 테스트 실행하기

test.support — 파이썬 테스트 스위트용 유틸리티

TestFailed

ResourceDenied

verbose

is_jython

is_android

unix_shell

LOOPBACK_TIMEOUT

INTERNET_TIMEOUT

SHORT_TIMEOUT

LONG_TIMEOUT

PGO

PIPE_MAX_SIZE

Py_DEBUG

SOCK_MAX_SIZE

TEST_SUPPORT_DIR

TEST_HOME_DIR

TEST_DATA_DIR

MAX_Py_ssize_t

max_memuse

real_max_memuse

MISSING_C_DOCSTRINGS

HAVE_DOCSTRINGS

TEST_HTTP_URL

ALWAYS_EQ

NEVER_EQ

LARGEST

SMALLEST

busy_retry()

sleeping_retry()

is_resource_enabled()

python_is_optimized()

with_pymalloc()

requires()

sortdict()

findfile()

get_pagesize()

setswitchinterval()

check_impl_detail()

set_memlimit()

record_original_stdout()

get_original_stdout()

args_from_interpreter_flags()

optim_args_from_interpreter_flags()

captured_stdin()

captured_stdout()

captured_stderr()

disable_faulthandler()

gc_collect()

disable_gc()

swap_attr()

swap_item()

flush_std_streams()

print_warning()

wait_process()

calcobjsize()

calcvobjsize()

checksizeof()

anticipate_failure()

system_must_validate_cert()

run_with_locale()

run_with_tz()

requires_freebsd_version()

requires_linux_version()

requires_mac_version()

requires_gil_enabled()

requires_IEEE_754()

requires_zlib()

requires_gzip()

requires_bz2()

requires_lzma()

requires_resource()

requires_docstrings()

requires_limited_api()

cpython_only()

impl_detail()

no_tracing()

refcount_test()

bigmemtest()

bigaddrspacetest()

check_syntax_error()

open_urlresource()

reap_children()

get_attribute()

catch_unraisable_exception()

load_package_tests()

detect_api_mismatch()

patch()

run_in_subinterp()

check_free_after_iterating()

missing_compiler_executable()

check__all__()

skip_if_broken_multiprocessing_synchronize()

check_disallow_instantiation()

adjust_int_max_str_digits()

SuppressCrashReport

SaveSignals

save()

restore()

Matcher

matches()

match_value()

test.support.socket_helper — 소켓 테스트용 유틸리티

IPV6_ENABLED

find_unused_port()

bind_port()

bind_unix_socket()

skip_unless_bind_unix_socket()

transient_internet()

test.support.script_helper — 파이썬 실행 테스트용 유틸리티

interpreter_requires_environment()

run_python_until_end()

assert_python_ok()

assert_python_failure()

spawn_python()

kill_python()

make_script()

make_zip_script()

make_pkg()

make_zip_pkg()

test.support.bytecode_helper — 올바른 바이트 코드 생성 테스트를 위한 지원 도구

BytecodeTestCase

get_disassembly_as_string()

assertInBytecode()

assertNotInBytecode()

test.support.threading_helper — Utilities for threading tests

join_thread()

reap_threads()

start_threads()

threading_cleanup()

threading_setup()

wait_threads_exit()

catch_threading_exception()

test.support.os_helper — Utilities for os tests

FS_NONASCII

SAVEDCWD

TESTFN

TESTFN_NONASCII

TESTFN_UNENCODABLE

TESTFN_UNDECODABLE

TESTFN_UNICODE

EnvironmentVarGuard

FakePath

set()

unset()

can_symlink()

can_xattr()

change_cwd()

create_empty_file()

fd_count()

fs_is_case_insensitive()

make_bad_fd()

rmdir()

rmtree()

skip_unless_symlink()

skip_unless_xattr()

temp_cwd()

temp_dir()

temp_umask()

unlink()

test.support.import_helper — Utilities for import tests

forget()

import_fresh_module()

import_module()

modules_setup()

modules_cleanup()

unload()

make_legacy_pyc()

CleanImport

DirsOnSysPath

test.support.warnings_helper — Utilities for warnings tests

ignore_warnings()

check_no_resource_warning()

check_syntax_warning()

check_warnings()

WarningsRecorder

typing — 형 힌트 지원

Added in version 3.5.

소스 코드: Lib/typing.py [https://github.com/python/cpython/tree/main/Lib/typing.py]

참고

The Python runtime does not enforce function and variable type annotations. They can be used by third party tools such as type checkers, IDEs, linters, etc.

This module provides runtime support for type hints.

Consider the function below:

def surface_area_of_cube(edge_length: float) -> str:
    return f"The surface area of the cube is {6 * edge_length ** 2}."

The function surface_area_of_cube takes an argument expected to be an instance of float, as indicated by the type hint edge_length: float. The function is expected to return an instance of str, as indicated by the -> str hint.

While type hints can be simple classes like float or str, they can also be more complex. The typing module provides a vocabulary of more advanced type hints.

New features are frequently added to the typing module. The typing_extensions [https://pypi.org/project/typing_extensions/] package provides backports of these new features to older versions of Python.

더 보기

“Typing cheat sheet” [https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html]

A quick overview of type hints (hosted at the mypy docs)

“Type System Reference” section of the mypy docs [https://mypy.readthedocs.io/en/stable/index.html]

The Python typing system is standardised via PEPs, so this reference should broadly apply to most Python type checkers. (Some parts may still be specific to mypy.)

“Static Typing with Python” [https://typing.readthedocs.io/en/latest/]

Type-checker-agnostic documentation written by the community detailing type system features, useful typing related tools and typing best practices.

Specification for the Python Type System

The canonical, up-to-date specification of the Python type system can be found at “Specification for the Python type system” [https://typing.readthedocs.io/en/latest/spec/index.html].

형 에일리어스

A type alias is defined using the type statement, which creates an instance of TypeAliasType. In this example, Vector and list[float] will be treated equivalently by static type checkers:

type Vector = list[float]

def scale(scalar: float, vector: Vector) -> Vector:
    return [scalar * num for num in vector]

# passes type checking; a list of floats qualifies as a Vector.
new_vector = scale(2.0, [1.0, -4.2, 5.4])

형 에일리어스는 복잡한 형 서명을 단순화하는 데 유용합니다. 예를 들면:

from collections.abc import Sequence

type ConnectionOptions = dict[str, str]
type Address = tuple[str, int]
type Server = tuple[Address, ConnectionOptions]

def broadcast_message(message: str, servers: Sequence[Server]) -> None:
    ...

# The static type checker will treat the previous type signature as
# being exactly equivalent to this one.
def broadcast_message(
    message: str,
    servers: Sequence[tuple[tuple[str, int], dict[str, str]]]
) -> None:
    ...

The type statement is new in Python 3.12. For backwards compatibility, type aliases can also be created through simple assignment:

Vector = list[float]

Or marked with TypeAlias to make it explicit that this is a type alias, not a normal variable assignment:

from typing import TypeAlias

Vector: TypeAlias = list[float]

NewType

Use the NewType helper to create distinct types:

from typing import NewType

UserId = NewType('UserId', int)
some_id = UserId(524313)

정적 형 검사기는 새 형을 원래 형의 서브 클래스인 것처럼 다룹니다. 논리 에러를 잡는 데 유용합니다:

def get_user_name(user_id: UserId) -> str:
    ...

# passes type checking
user_a = get_user_name(UserId(42351))

# fails type checking; an int is not a UserId
user_b = get_user_name(-1)

UserId 형의 변수에 대해 모든 int 연산을 여전히 수행할 수 있지만, 결과는 항상 int 형이 됩니다. 이것은 int가 기대되는 모든 곳에 UserId를 전달할 수 있지만, 잘못된 방식으로 의도하지 않게 UserId를 만들지 않도록 합니다:

# 'output' is of type 'int', not 'UserId'
output = UserId(23413) + UserId(54341)

Note that these checks are enforced only by the static type checker. At runtime, the statement Derived = NewType('Derived', Base) will make Derived a callable that immediately returns whatever parameter you pass it. That means the expression Derived(some_value) does not create a new class or introduce much overhead beyond that of a regular function call.

더욱 정확하게, 표현식 some_value is Derived(some_value)는 실행 시간에 항상 참입니다.

It is invalid to create a subtype of Derived:

from typing import NewType

UserId = NewType('UserId', int)

# Fails at runtime and does not pass type checking
class AdminUserId(UserId): pass

However, it is possible to create a NewType based on a ‘derived’ NewType:

from typing import NewType

UserId = NewType('UserId', int)

ProUserId = NewType('ProUserId', UserId)

그리고 ProUserId에 대한 형 검사는 예상대로 작동합니다.

자세한 내용은 PEP 484 [https://peps.python.org/pep-0484/]를 참조하십시오.

참고

Recall that the use of a type alias declares two types to be equivalent to one another. Doing type Alias = Original will make the static type checker treat Alias as being exactly equivalent to Original in all cases. This is useful when you want to simplify complex type signatures.

반면에, NewType은 한 형을 다른 형의 서브 형으로 선언합니다. Derived = NewType('Derived', Original)은 정적 형 검사기가 Derived를 Original의 서브 클래스로 취급하게 합니다. 이는 Original 형의 값이 Derived 형의 값이 예상되는 위치에서 사용될 수 없음을 의미합니다. 실행 시간 비용을 최소화하면서 논리 에러를 방지하려는 경우에 유용합니다.

Added in version 3.5.2.

버전 3.10에서 변경: NewType is now a class rather than a function. As a result, there is some additional runtime cost when calling NewType over a regular function.

버전 3.11에서 변경: The performance of calling NewType has been restored to its level in Python 3.9.

Annotating callable objects

Functions – or other callable objects – can be annotated using collections.abc.Callable or deprecated typing.Callable. Callable[[int], str] signifies a function that takes a single parameter of type int and returns a str.

For example:

from collections.abc import Callable, Awaitable

def feeder(get_next_item: Callable[[], str]) -> None:
    ...  # Body

def async_query(on_success: Callable[[int], None],
                on_error: Callable[[int, Exception], None]) -> None:
    ...  # Body

async def on_update(value: str) -> None:
    ...  # Body

callback: Callable[[str], Awaitable[None]] = on_update

The subscription syntax must always be used with exactly two values: the argument list and the return type. The argument list must be a list of types, a ParamSpec, Concatenate, or an ellipsis. The return type must be a single type.

If a literal ellipsis ... is given as the argument list, it indicates that a callable with any arbitrary parameter list would be acceptable:

def concat(x: str, y: str) -> str:
    return x + y

x: Callable[..., str]
x = str     # OK
x = concat  # Also OK

Callable cannot express complex signatures such as functions that take a variadic number of arguments, overloaded functions, or functions that have keyword-only parameters. However, these signatures can be expressed by defining a Protocol class with a __call__() method:

from collections.abc import Iterable
from typing import Protocol

class Combiner(Protocol):
    def __call__(self, *vals: bytes, maxlen: int | None = None) -> list[bytes]: ...

def batch_proc(data: Iterable[bytes], cb_results: Combiner) -> bytes:
    for item in data:
        ...

def good_cb(*vals: bytes, maxlen: int | None = None) -> list[bytes]:
    ...
def bad_cb(*vals: bytes, maxitems: int | None) -> list[bytes]:
    ...

batch_proc([], good_cb)  # OK
batch_proc([], bad_cb)   # Error! Argument 2 has incompatible type because of
                         # different name and kind in the callback

Callables which take other callables as arguments may indicate that their parameter types are dependent on each other using ParamSpec. Additionally, if that callable adds or removes arguments from other callables, the Concatenate operator may be used. They take the form Callable[ParamSpecVariable, ReturnType] and Callable[Concatenate[Arg1Type, Arg2Type, ..., ParamSpecVariable], ReturnType] respectively.

버전 3.10에서 변경: Callable now supports ParamSpec and Concatenate. See PEP 612 [https://peps.python.org/pep-0612/] for more details.

더 보기

The documentation for ParamSpec and Concatenate provides examples of usage in Callable.

제네릭

Since type information about objects kept in containers cannot be statically inferred in a generic way, many container classes in the standard library support subscription to denote the expected types of container elements.

from collections.abc import Mapping, Sequence

class Employee: ...

# Sequence[Employee] indicates that all elements in the sequence
# must be instances of "Employee".
# Mapping[str, str] indicates that all keys and all values in the mapping
# must be strings.
def notify_by_email(employees: Sequence[Employee],
                    overrides: Mapping[str, str]) -> None: ...

Generic functions and classes can be parameterized by using type parameter syntax:

from collections.abc import Sequence

def first[T](l: Sequence[T]) -> T:  # Function is generic over the TypeVar "T"
    return l[0]

Or by using the TypeVar factory directly:

from collections.abc import Sequence
from typing import TypeVar

U = TypeVar('U')                  # Declare type variable "U"

def second(l: Sequence[U]) -> U:  # Function is generic over the TypeVar "U"
    return l[1]

버전 3.12에서 변경: Syntactic support for generics is new in Python 3.12.

Annotating tuples

For most containers in Python, the typing system assumes that all elements in the container will be of the same type. For example:

from collections.abc import Mapping

# Type checker will infer that all elements in ``x`` are meant to be ints
x: list[int] = []

# Type checker error: ``list`` only accepts a single type argument:
y: list[int, str] = [1, 'foo']

# Type checker will infer that all keys in ``z`` are meant to be strings,
# and that all values in ``z`` are meant to be either strings or ints
z: Mapping[str, str | int] = {}

list only accepts one type argument, so a type checker would emit an error on the y assignment above. Similarly, Mapping only accepts two type arguments: the first indicates the type of the keys, and the second indicates the type of the values.

Unlike most other Python containers, however, it is common in idiomatic Python code for tuples to have elements which are not all of the same type. For this reason, tuples are special-cased in Python’s typing system. tuple accepts any number of type arguments:

# OK: ``x`` is assigned to a tuple of length 1 where the sole element is an int
x: tuple[int] = (5,)

# OK: ``y`` is assigned to a tuple of length 2;
# element 1 is an int, element 2 is a str
y: tuple[int, str] = (5, "foo")

# Error: the type annotation indicates a tuple of length 1,
# but ``z`` has been assigned to a tuple of length 3
z: tuple[int] = (1, 2, 3)

To denote a tuple which could be of any length, and in which all elements are of the same type T, use tuple[T, ...]. To denote an empty tuple, use tuple[()]. Using plain tuple as an annotation is equivalent to using tuple[Any, ...]:

x: tuple[int, ...] = (1, 2)
# These reassignments are OK: ``tuple[int, ...]`` indicates x can be of any length
x = (1, 2, 3)
x = ()
# This reassignment is an error: all elements in ``x`` must be ints
x = ("foo", "bar")

# ``y`` can only ever be assigned to an empty tuple
y: tuple[()] = ()

z: tuple = ("foo", "bar")
# These reassignments are OK: plain ``tuple`` is equivalent to ``tuple[Any, ...]``
z = (1, 2, 3)
z = ()

The type of class objects

A variable annotated with C may accept a value of type C. In contrast, a variable annotated with type[C] (or deprecated typing.Type[C]) may accept values that are classes themselves – specifically, it will accept the class object of C. For example:

a = 3         # Has type ``int``
b = int       # Has type ``type[int]``
c = type(a)   # Also has type ``type[int]``

Note that type[C] is covariant:

class User: ...
class ProUser(User): ...
class TeamUser(User): ...

def make_new_user(user_class: type[User]) -> User:
    # ...
    return user_class()

make_new_user(User)      # OK
make_new_user(ProUser)   # Also OK: ``type[ProUser]`` is a subtype of ``type[User]``
make_new_user(TeamUser)  # Still fine
make_new_user(User())    # Error: expected ``type[User]`` but got ``User``
make_new_user(int)       # Error: ``type[int]`` is not a subtype of ``type[User]``

The only legal parameters for type are classes, Any, type variables, and unions of any of these types. For example:

def new_non_team_user(user_class: type[BasicUser | ProUser]): ...

new_non_team_user(BasicUser)  # OK
new_non_team_user(ProUser)    # OK
new_non_team_user(TeamUser)   # Error: ``type[TeamUser]`` is not a subtype
                              # of ``type[BasicUser | ProUser]``
new_non_team_user(User)       # Also an error

type[Any] is equivalent to type, which is the root of Python’s metaclass hierarchy.

Annotating generators and coroutines

A generator can be annotated using the generic type Generator[YieldType, SendType, ReturnType]. For example:

def echo_round() -> Generator[int, float, str]:
    sent = yield 0
    while sent >= 0:
        sent = yield round(sent)
    return 'Done'

Note that unlike many other generic classes in the standard library, the SendType of Generator behaves contravariantly, not covariantly or invariantly.

The SendType and ReturnType parameters default to None:

def infinite_stream(start: int) -> Generator[int]:
    while True:
        yield start
        start += 1

It is also possible to set these types explicitly:

def infinite_stream(start: int) -> Generator[int, None, None]:
    while True:
        yield start
        start += 1

Simple generators that only ever yield values can also be annotated as having a return type of either Iterable[YieldType] or Iterator[YieldType]:

def infinite_stream(start: int) -> Iterator[int]:
    while True:
        yield start
        start += 1

Async generators are handled in a similar fashion, but don’t expect a ReturnType type argument (AsyncGenerator[YieldType, SendType]). The SendType argument defaults to None, so the following definitions are equivalent:

async def infinite_stream(start: int) -> AsyncGenerator[int]:
    while True:
        yield start
        start = await increment(start)

async def infinite_stream(start: int) -> AsyncGenerator[int, None]:
    while True:
        yield start
        start = await increment(start)

As in the synchronous case, AsyncIterable[YieldType] and AsyncIterator[YieldType] are available as well:

async def infinite_stream(start: int) -> AsyncIterator[int]:
    while True:
        yield start
        start = await increment(start)

Coroutines can be annotated using Coroutine[YieldType, SendType, ReturnType]. Generic arguments correspond to those of Generator, for example:

from collections.abc import Coroutine
c: Coroutine[list[str], str, int]  # Some coroutine defined elsewhere
x = c.send('hi')                   # Inferred type of 'x' is list[str]
async def bar() -> None:
    y = await c                    # Inferred type of 'y' is int

사용자 정의 제네릭 형

사용자 정의 클래스는 제네릭 클래스로 정의 할 수 있습니다.

from logging import Logger

class LoggedVar[T]:
    def __init__(self, value: T, name: str, logger: Logger) -> None:
        self.name = name
        self.logger = logger
        self.value = value

    def set(self, new: T) -> None:
        self.log('Set ' + repr(self.value))
        self.value = new

    def get(self) -> T:
        self.log('Get ' + repr(self.value))
        return self.value

    def log(self, message: str) -> None:
        self.logger.info('%s: %s', self.name, message)

This syntax indicates that the class LoggedVar is parameterised around a single type variable T . This also makes T valid as a type within the class body.

Generic classes implicitly inherit from Generic. For compatibility with Python 3.11 and lower, it is also possible to inherit explicitly from Generic to indicate a generic class:

from typing import TypeVar, Generic

T = TypeVar('T')

class LoggedVar(Generic[T]):
    ...

Generic classes have __class_getitem__() methods, meaning they can be parameterised at runtime (e.g. LoggedVar[int] below):

from collections.abc import Iterable

def zero_all_vars(vars: Iterable[LoggedVar[int]]) -> None:
    for var in vars:
        var.set(0)

A generic type can have any number of type variables. All varieties of TypeVar are permissible as parameters for a generic type:

from typing import TypeVar, Generic, Sequence

class WeirdTrio[T, B: Sequence[bytes], S: (int, str)]:
    ...

OldT = TypeVar('OldT', contravariant=True)
OldB = TypeVar('OldB', bound=Sequence[bytes], covariant=True)
OldS = TypeVar('OldS', int, str)

class OldWeirdTrio(Generic[OldT, OldB, OldS]):
    ...

Generic에 대한 각 형 변수 인자는 달라야 합니다. 그래서 이것은 잘못되었습니다:

from typing import TypeVar, Generic
...

class Pair[M, M]:  # SyntaxError
    ...

T = TypeVar('T')

class Pair(Generic[T, T]):   # INVALID
    ...

Generic classes can also inherit from other classes:

from collections.abc import Sized

class LinkedList[T](Sized):
    ...

When inheriting from generic classes, some type parameters could be fixed:

from collections.abc import Mapping

class MyDict[T](Mapping[str, T]):
    ...

이 경우 MyDict는 단일 매개 변수 T를 갖습니다.

Using a generic class without specifying type parameters assumes Any for each position. In the following example, MyIterable is not generic but implicitly inherits from Iterable[Any]:

from collections.abc import Iterable

class MyIterable(Iterable): # Same as Iterable[Any]
    ...

User-defined generic type aliases are also supported. Examples:

from collections.abc import Iterable

type Response[S] = Iterable[S] | int

# Return type here is same as Iterable[str] | int
def response(query: str) -> Response[str]:
    ...

type Vec[T] = Iterable[tuple[T, T]]

def inproduct[T: (int, float, complex)](v: Vec[T]) -> T: # Same as Iterable[tuple[T, T]]
    return sum(x*y for x, y in v)

For backward compatibility, generic type aliases can also be created through a simple assignment:

from collections.abc import Iterable
from typing import TypeVar

S = TypeVar("S")
Response = Iterable[S] | int

버전 3.7에서 변경: Generic에는 더는 사용자 정의 메타 클래스가 없습니다.

버전 3.12에서 변경: Syntactic support for generics and type aliases is new in version 3.12. Previously, generic classes had to explicitly inherit from Generic or contain a type variable in one of their bases.

User-defined generics for parameter expressions are also supported via parameter specification variables in the form [**P]. The behavior is consistent with type variables’ described above as parameter specification variables are treated by the typing module as a specialized type variable. The one exception to this is that a list of types can be used to substitute a ParamSpec:

>>> class Z[T, **P]: ...  # T is a TypeVar; P is a ParamSpec
...
>>> Z[int, [dict, float]]
__main__.Z[int, [dict, float]]

Classes generic over a ParamSpec can also be created using explicit inheritance from Generic. In this case, ** is not used:

from typing import ParamSpec, Generic

P = ParamSpec('P')

class Z(Generic[P]):
    ...

Another difference between TypeVar and ParamSpec is that a generic with only one parameter specification variable will accept parameter lists in the forms X[[Type1, Type2, ...]] and also X[Type1, Type2, ...] for aesthetic reasons. Internally, the latter is converted to the former, so the following are equivalent:

>>> class X[**P]: ...
...
>>> X[int, str]
__main__.X[[int, str]]
>>> X[[int, str]]
__main__.X[[int, str]]

Note that generics with ParamSpec may not have correct __parameters__ after substitution in some cases because they are intended primarily for static type checking.

버전 3.10에서 변경: Generic can now be parameterized over parameter expressions. See ParamSpec and PEP 612 [https://peps.python.org/pep-0612/] for more details.

A user-defined generic class can have ABCs as base classes without a metaclass conflict. Generic metaclasses are not supported. The outcome of parameterizing generics is cached, and most types in the typing module are hashable and comparable for equality.

Any 형

특수한 종류의 형은 Any입니다. 정적 형 검사기는 모든 형을 Any와 호환되는 것으로, Any를 모든 형과 호환되는 것으로 취급합니다.

이것은 Any 형의 값에 대해 어떤 연산이나 메서드 호출을 수행하고, 그것을 임의의 변수에 대입할 수 있다는 것을 의미합니다:

from typing import Any

a: Any = None
a = []          # OK
a = 2           # OK

s: str = ''
s = a           # OK

def foo(item: Any) -> int:
    # Passes type checking; 'item' could be any type,
    # and that type might have a 'bar' method
    item.bar()
    ...

Notice that no type checking is performed when assigning a value of type Any to a more precise type. For example, the static type checker did not report an error when assigning a to s even though s was declared to be of type str and receives an int value at runtime!

또한, 반환형이나 매개 변수 형이 없는 모든 함수는 묵시적으로 Any 기본값을 사용합니다:

def legacy_parser(text):
    ...
    return data

# A static type checker will treat the above
# as having the same signature as:
def legacy_parser(text: Any) -> Any:
    ...
    return data

이 동작은 여러분이 동적으로 형이 지정되는 코드와 정적으로 형이 지정되는 코드를 혼합해야 할 때 Any를 탈출구로 사용할 수 있도록 합니다.

Any의 동작과 object의 동작을 대조하십시오. Any와 유사하게, 모든 형은 object의 서브 형입니다. 그러나, Any와는 달리, 그 반대는 사실이 아닙니다: object는 다른 모든 형의 서브 형이 아닙니다.

이것은 값의 형이 object일 때, 형 검사기가 그것에 대한 거의 모든 연산을 거부하고, 그것을 더 특수한 형의 변수에 대입(또는 그것을 반환 값으로 사용)하는 것이 형 에러임을 의미합니다. 예를 들면:

def hash_a(item: object) -> int:
    # Fails type checking; an object does not have a 'magic' method.
    item.magic()
    ...

def hash_b(item: Any) -> int:
    # Passes type checking
    item.magic()
    ...

# Passes type checking, since ints and strs are subclasses of object
hash_a(42)
hash_a("foo")

# Passes type checking, since Any is compatible with all types
hash_b(42)
hash_b("foo")

값이 형 안전한 방식으로 모든 형이 될 수 있음을 표시하려면 object를 사용하십시오. 값이 동적으로 형이 지정됨을 표시하려면 Any를 사용하십시오.

명목적 대 구조적 서브 타이핑

Initially PEP 484 [https://peps.python.org/pep-0484/] defined the Python static type system as using nominal subtyping. This means that a class A is allowed where a class B is expected if and only if A is a subclass of B.

이 요구 사항은 이전에 Iterable과 같은 추상 베이스 클래스에도 적용되었습니다. 이 접근 방식의 문제점은 이것을 지원하려면 클래스를 명시적으로 표시해야만 한다는 점입니다. 이는 파이썬답지 않고 관용적인 동적으로 형이 지정된 파이썬 코드에서 일반적으로 수행하는 것과는 다릅니다. 예를 들어, 이것은 PEP 484 [https://peps.python.org/pep-0484/]를 만족합니다:

from collections.abc import Sized, Iterable, Iterator

class Bucket(Sized, Iterable[int]):
    ...
    def __len__(self) -> int: ...
    def __iter__(self) -> Iterator[int]: ...

PEP 544 [https://peps.python.org/pep-0544/]는 사용자가 클래스 정의에서 명시적인 베이스 클래스 없이 위의 코드를 작성할 수 있게 함으로써 이 문제를 풀도록 합니다. 정적 형 검사기가 Bucket을 Sized와 Iterable[int]의 서브 형으로 묵시적으로 취급하도록 합니다. 이것은 구조적 서브 타이핑(structural subtyping)(또는 정적 덕 타이핑)으로 알려져 있습니다:

from collections.abc import Iterator, Iterable

class Bucket:  # Note: no base classes
    ...
    def __len__(self) -> int: ...
    def __iter__(self) -> Iterator[int]: ...

def collect(items: Iterable[int]) -> int: ...
result = collect(Bucket())  # Passes type check

또한, 특별한 클래스 Protocol을 서브 클래싱 함으로써, 사용자는 새로운 사용자 정의 프로토콜을 정의하여 구조적 서브 타이핑을 완전히 누릴 수 있습니다 (아래 예를 참조하십시오).

모듈 내용

The typing module defines the following classes, functions and decorators.

특수 타이핑 프리미티브

특수형

These can be used as types in annotations. They do not support subscription using [].

typing.Any

제한되지 않는 형을 나타내는 특수형.

모든 형은 Any와 호환됩니다.

Any는 모든 형과 호환됩니다.

버전 3.11에서 변경: Any can now be used as a base class. This can be useful for avoiding type checker errors with classes that can duck type anywhere or are highly dynamic.

typing.AnyStr

A constrained type variable.

Definition:

AnyStr = TypeVar('AnyStr', str, bytes)

AnyStr is meant to be used for functions that may accept str or bytes arguments but cannot allow the two to mix.

예를 들면:

def concat(a: AnyStr, b: AnyStr) -> AnyStr:
    return a + b

concat("foo", "bar")    # OK, output has type 'str'
concat(b"foo", b"bar")  # OK, output has type 'bytes'
concat("foo", b"bar")   # Error, cannot mix str and bytes

Note that, despite its name, AnyStr has nothing to do with the Any type, nor does it mean “any string”. In particular, AnyStr and str | bytes are different from each other and have different use cases:

# Invalid use of AnyStr:
# The type variable is used only once in the function signature,
# so cannot be "solved" by the type checker
def greet_bad(cond: bool) -> AnyStr:
    return "hi there!" if cond else b"greetings!"

# The better way of annotating this function:
def greet_proper(cond: bool) -> str | bytes:
    return "hi there!" if cond else b"greetings!"

Deprecated since version 3.13, will be removed in version 3.18: Deprecated in favor of the new type parameter syntax. Use class A[T: (str, bytes)]: ... instead of importing AnyStr. See PEP 695 [https://peps.python.org/pep-0695/] for more details.

In Python 3.16, AnyStr will be removed from typing.__all__, and deprecation warnings will be emitted at runtime when it is accessed or imported from typing. AnyStr will be removed from typing in Python 3.18.

typing.LiteralString

Special type that includes only literal strings.

Any string literal is compatible with LiteralString, as is another LiteralString. However, an object typed as just str is not. A string created by composing LiteralString-typed objects is also acceptable as a LiteralString.

Example:

def run_query(sql: LiteralString) -> None:
    ...

def caller(arbitrary_string: str, literal_string: LiteralString) -> None:
    run_query("SELECT * FROM students")  # OK
    run_query(literal_string)  # OK
    run_query("SELECT * FROM " + literal_string)  # OK
    run_query(arbitrary_string)  # type checker error
    run_query(  # type checker error
        f"SELECT * FROM students WHERE name = {arbitrary_string}"
    )

LiteralString is useful for sensitive APIs where arbitrary user-generated strings could generate problems. For example, the two cases above that generate type checker errors could be vulnerable to an SQL injection attack.

See PEP 675 [https://peps.python.org/pep-0675/] for more details.

Added in version 3.11.

typing.Never

typing.NoReturn

Never and NoReturn represent the bottom type [https://en.wikipedia.org/wiki/Bottom_type], a type that has no members.

They can be used to indicate that a function never returns, such as sys.exit():

from typing import Never  # or NoReturn

def stop() -> Never:
    raise RuntimeError('no way')

Or to define a function that should never be called, as there are no valid arguments, such as assert_never():

from typing import Never  # or NoReturn

def never_call_me(arg: Never) -> None:
    pass

def int_or_str(arg: int | str) -> None:
    never_call_me(arg)  # type checker error
    match arg:
        case int():
            print("It's an int")
        case str():
            print("It's a str")
        case _:
            never_call_me(arg)  # OK, arg is of type Never (or NoReturn)

Never and NoReturn have the same meaning in the type system and static type checkers treat both equivalently.

Added in version 3.6.2: Added NoReturn.

Added in version 3.11: Added Never.

typing.Self

Special type to represent the current enclosed class.

예를 들면:

from typing import Self, reveal_type

class Foo:
    def return_self(self) -> Self:
        ...
        return self

class SubclassOfFoo(Foo): pass

reveal_type(Foo().return_self())  # Revealed type is "Foo"
reveal_type(SubclassOfFoo().return_self())  # Revealed type is "SubclassOfFoo"

This annotation is semantically equivalent to the following, albeit in a more succinct fashion:

from typing import TypeVar

Self = TypeVar("Self", bound="Foo")

class Foo:
    def return_self(self: Self) -> Self:
        ...
        return self

In general, if something returns self, as in the above examples, you should use Self as the return annotation. If Foo.return_self was annotated as returning "Foo", then the type checker would infer the object returned from SubclassOfFoo.return_self as being of type Foo rather than SubclassOfFoo.

Other common use cases include:

classmethods that are used as alternative constructors and return instances of the cls parameter.

Annotating an __enter__() method which returns self.

You should not use Self as the return annotation if the method is not guaranteed to return an instance of a subclass when the class is subclassed:

class Eggs:
    # Self would be an incorrect return annotation here,
    # as the object returned is always an instance of Eggs,
    # even in subclasses
    def returns_eggs(self) -> "Eggs":
        return Eggs()

See PEP 673 [https://peps.python.org/pep-0673/] for more details.

Added in version 3.11.

typing.TypeAlias

Special annotation for explicitly declaring a type alias.

예를 들면:

from typing import TypeAlias

Factors: TypeAlias = list[int]

TypeAlias is particularly useful on older Python versions for annotating aliases that make use of forward references, as it can be hard for type checkers to distinguish these from normal variable assignments:

from typing import Generic, TypeAlias, TypeVar

T = TypeVar("T")

# "Box" does not exist yet,
# so we have to use quotes for the forward reference on Python <3.12.
# Using ``TypeAlias`` tells the type checker that this is a type alias declaration,
# not a variable assignment to a string.
BoxOfStrings: TypeAlias = "Box[str]"

class Box(Generic[T]):
    @classmethod
    def make_box_of_strings(cls) -> BoxOfStrings: ...

See PEP 613 [https://peps.python.org/pep-0613/] for more details.

Added in version 3.10.

버전 3.12부터 폐지됨: TypeAlias is deprecated in favor of the type statement, which creates instances of TypeAliasType and which natively supports forward references. Note that while TypeAlias and TypeAliasType serve similar purposes and have similar names, they are distinct and the latter is not the type of the former. Removal of TypeAlias is not currently planned, but users are encouraged to migrate to type statements.

특수 형태

These can be used as types in annotations. They all support subscription using [], but each has a unique syntax.

typing.Union

Union type; Union[X, Y] is equivalent to X | Y and means either X or Y.

To define a union, use e.g. Union[int, str] or the shorthand int | str. Using that shorthand is recommended. Details:

인자는 형이어야 하며 적어도 하나 있어야 합니다.

공용체의 공용체는 펼쳐집니다, 예를 들어:

Union[Union[int, str], float] == Union[int, str, float]

단일 인자의 공용체는 사라집니다. 예를 들어:

Union[int] == int  # The constructor actually returns int

중복 인자는 건너뜁니다. 예를 들어:

Union[int, str, int] == Union[int, str] == int | str

공용체를 비교할 때, 인자 순서가 무시됩니다, 예를 들어:

Union[int, str] == Union[str, int]

You cannot subclass or instantiate a Union.

Union[X][Y]라고 쓸 수 없습니다.

버전 3.7에서 변경: 실행 시간에 공용체의 명시적 서브 클래스를 제거하지 않습니다.

버전 3.10에서 변경: Unions can now be written as X | Y. See union type expressions.

typing.Optional

Optional[X] is equivalent to X | None (or Union[X, None]).

이는 기본값을 갖는 선택적 인자와 같은 개념이 아님에 유의하십시오. 단지 선택적이기 때문에 기본값을 갖는 선택적 인자가 형 어노테이션에 Optional 한정자가 필요하지는 않습니다. 예를 들면:

def foo(arg: int = 0) -> None:
    ...

한편, 명시적인 None 값이 허용되면, 인자가 선택적인지와 관계없이 Optional을 사용하는 것이 적합합니다. 예를 들면:

def foo(arg: Optional[int] = None) -> None:
    ...

버전 3.10에서 변경: Optional can now be written as X | None. See union type expressions.

typing.Concatenate

Special form for annotating higher-order functions.

Concatenate can be used in conjunction with Callable and ParamSpec to annotate a higher-order callable which adds, removes, or transforms parameters of another callable. Usage is in the form Concatenate[Arg1Type, Arg2Type, ..., ParamSpecVariable]. Concatenate is currently only valid when used as the first argument to a Callable. The last parameter to Concatenate must be a ParamSpec or ellipsis (...).

For example, to annotate a decorator with_lock which provides a threading.Lock to the decorated function, Concatenate can be used to indicate that with_lock expects a callable which takes in a Lock as the first argument, and returns a callable with a different type signature. In this case, the ParamSpec indicates that the returned callable’s parameter types are dependent on the parameter types of the callable being passed in:

from collections.abc import Callable
from threading import Lock
from typing import Concatenate

# Use this lock to ensure that only one thread is executing a function
# at any time.
my_lock = Lock()

def with_lock[**P, R](f: Callable[Concatenate[Lock, P], R]) -> Callable[P, R]:
    '''A type-safe decorator which provides a lock.'''
    def inner(*args: P.args, **kwargs: P.kwargs) -> R:
        # Provide the lock as the first argument.
        return f(my_lock, *args, **kwargs)
    return inner

@with_lock
def sum_threadsafe(lock: Lock, numbers: list[float]) -> float:
    '''Add a list of numbers together in a thread-safe manner.'''
    with lock:
        return sum(numbers)

# We don't need to pass in the lock ourselves thanks to the decorator.
sum_threadsafe([1.1, 2.2, 3.3])

Added in version 3.10.

더 보기

PEP 612 [https://peps.python.org/pep-0612/] – Parameter Specification Variables (the PEP which introduced ParamSpec and Concatenate)

ParamSpec

Annotating callable objects

typing.Literal

Special typing form to define “literal types”.

Literal can be used to indicate to type checkers that the annotated object has a value equivalent to one of the provided literals.

예를 들면:

def validate_simple(data: Any) -> Literal[True]:  # always returns True
    ...

type Mode = Literal['r', 'rb', 'w', 'wb']
def open_helper(file: str, mode: Mode) -> str:
    ...

open_helper('/some/path', 'r')      # Passes type check
open_helper('/other/path', 'typo')  # Error in type checker

Literal[...]은 서브 클래싱 될 수 없습니다. 실행 시간에는, 임의의 값이 Literal[...]에 대한 형 인자로 허용되지만, 형 검사기는 제한을 부과할 수 있습니다. 리터럴 형에 대한 자세한 내용은 PEP 586 [https://peps.python.org/pep-0586/]을 참조하십시오.

Added in version 3.8.

버전 3.9.1에서 변경: Literal now de-duplicates parameters. Equality comparisons of Literal objects are no longer order dependent. Literal objects will now raise a TypeError exception during equality comparisons if one of their parameters are not hashable.

typing.ClassVar

클래스 변수를 표시하기 위한 특수 형 구조물.

PEP 526 [https://peps.python.org/pep-0526/]에서 소개된 것처럼, ClassVar로 감싼 변수 어노테이션은 주어진 어트리뷰트가 클래스 변수로 사용되도록 의도되었으며 해당 클래스의 인스턴스에 설정되어서는 안 됨을 나타냅니다. 용법:

class Starship:
    stats: ClassVar[dict[str, int]] = {} # class variable
    damage: int = 10                     # instance variable

ClassVar는 형만 받아들이며 더는 서브 스크립트 할 수 없습니다.

ClassVar는 클래스 자체가 아니므로, isinstance()나 issubclass()와 함께 사용하면 안 됩니다. ClassVar는 파이썬 실행 시간 동작을 변경하지 않지만, 제삼자 형 검사기에서 사용할 수 있습니다. 예를 들어, 형 검사기는 다음 코드를 에러로 표시 할 수 있습니다:

enterprise_d = Starship(3000)
enterprise_d.stats = {} # Error, setting class variable on instance
Starship.stats = {}     # This is OK

Added in version 3.5.3.

버전 3.13에서 변경: ClassVar can now be nested in Final and vice versa.

typing.Final

Special typing construct to indicate final names to type checkers.

Final names cannot be reassigned in any scope. Final names declared in class scopes cannot be overridden in subclasses.

예를 들면:

MAX_SIZE: Final = 9000
MAX_SIZE += 1  # Error reported by type checker

class Connection:
    TIMEOUT: Final[int] = 10

class FastConnector(Connection):
    TIMEOUT = 1  # Error reported by type checker

이러한 속성에 대한 실행 시간 검사는 없습니다. 자세한 내용은 PEP 591 [https://peps.python.org/pep-0591/]을 참조하십시오.

Added in version 3.8.

버전 3.13에서 변경: Final can now be nested in ClassVar and vice versa.

typing.Required

Special typing construct to mark a TypedDict key as required.

This is mainly useful for total=False TypedDicts. See TypedDict and PEP 655 [https://peps.python.org/pep-0655/] for more details.

Added in version 3.11.

typing.NotRequired

Special typing construct to mark a TypedDict key as potentially missing.

See TypedDict and PEP 655 [https://peps.python.org/pep-0655/] for more details.

Added in version 3.11.

typing.ReadOnly

A special typing construct to mark an item of a TypedDict as read-only.

예를 들면:

class Movie(TypedDict):
   title: ReadOnly[str]
   year: int

def mutate_movie(m: Movie) -> None:
   m["year"] = 1999  # allowed
   m["title"] = "The Matrix"  # typechecker error

There is no runtime checking for this property.

See TypedDict and PEP 705 [https://peps.python.org/pep-0705/] for more details.

Added in version 3.13.

typing.Annotated

Special typing form to add context-specific metadata to an annotation.

Add metadata x to a given type T by using the annotation Annotated[T, x]. Metadata added using Annotated can be used by static analysis tools or at runtime. At runtime, the metadata is stored in a __metadata__ attribute.

If a library or tool encounters an annotation Annotated[T, x] and has no special logic for the metadata, it should ignore the metadata and simply treat the annotation as T. As such, Annotated can be useful for code that wants to use annotations for purposes outside Python’s static typing system.

Using Annotated[T, x] as an annotation still allows for static typechecking of T, as type checkers will simply ignore the metadata x. In this way, Annotated differs from the @no_type_check decorator, which can also be used for adding annotations outside the scope of the typing system, but completely disables typechecking for a function or class.

The responsibility of how to interpret the metadata lies with the tool or library encountering an Annotated annotation. A tool or library encountering an Annotated type can scan through the metadata elements to determine if they are of interest (e.g., using isinstance()).

Annotated[<type>, <metadata>]

Here is an example of how you might use Annotated to add metadata to type annotations if you were doing range analysis:

@dataclass
class ValueRange:
    lo: int
    hi: int

T1 = Annotated[int, ValueRange(-10, 5)]
T2 = Annotated[T1, ValueRange(-20, 3)]

Details of the syntax:

Annotated의 첫 번째 인자는 유효한 형이어야 합니다

Multiple metadata elements can be supplied (Annotated supports variadic arguments):

@dataclass
class ctype:
    kind: str

Annotated[int, ValueRange(3, 10), ctype("char")]

It is up to the tool consuming the annotations to decide whether the client is allowed to add multiple metadata elements to one annotation and how to merge those annotations.

Annotated must be subscripted with at least two arguments ( Annotated[int] is not valid)

The order of the metadata elements is preserved and matters for equality checks:

assert Annotated[int, ValueRange(3, 10), ctype("char")] != Annotated[
    int, ctype("char"), ValueRange(3, 10)
]

Nested Annotated types are flattened. The order of the metadata elements starts with the innermost annotation:

assert Annotated[Annotated[int, ValueRange(3, 10)], ctype("char")] == Annotated[
    int, ValueRange(3, 10), ctype("char")
]

Duplicated metadata elements are not removed:

assert Annotated[int, ValueRange(3, 10)] != Annotated[
    int, ValueRange(3, 10), ValueRange(3, 10)
]

Annotated can be used with nested and generic aliases:

@dataclass
class MaxLen:
    value: int

type Vec[T] = Annotated[list[tuple[T, T]], MaxLen(10)]

# When used in a type annotation, a type checker will treat "V" the same as
# ``Annotated[list[tuple[int, int]], MaxLen(10)]``:
type V = Vec[int]

Annotated cannot be used with an unpacked TypeVarTuple:

type Variadic[*Ts] = Annotated[*Ts, Ann1]  # NOT valid

This would be equivalent to:

Annotated[T1, T2, T3, ..., Ann1]

where T1, T2, etc. are TypeVars. This would be invalid: only one type should be passed to Annotated.

By default, get_type_hints() strips the metadata from annotations. Pass include_extras=True to have the metadata preserved:

>>> from typing import Annotated, get_type_hints
>>> def func(x: Annotated[int, "metadata"]) -> None: pass
...
>>> get_type_hints(func)
{'x': <class 'int'>, 'return': <class 'NoneType'>}
>>> get_type_hints(func, include_extras=True)
{'x': typing.Annotated[int, 'metadata'], 'return': <class 'NoneType'>}

At runtime, the metadata associated with an Annotated type can be retrieved via the __metadata__ attribute:

>>> from typing import Annotated
>>> X = Annotated[int, "very", "important", "metadata"]
>>> X
typing.Annotated[int, 'very', 'important', 'metadata']
>>> X.__metadata__
('very', 'important', 'metadata')

At runtime, if you want to retrieve the original type wrapped by Annotated, use the __origin__ attribute:

>>> from typing import Annotated, get_origin
>>> Password = Annotated[str, "secret"]
>>> Password.__origin__
<class 'str'>

Note that using get_origin() will return Annotated itself:

>>> get_origin(Password)
typing.Annotated

더 보기

PEP 593 [https://peps.python.org/pep-0593/] - Flexible function and variable annotations

The PEP introducing Annotated to the standard library.

Added in version 3.9.

typing.TypeIs

Special typing construct for marking user-defined type predicate functions.

TypeIs can be used to annotate the return type of a user-defined type predicate function. TypeIs only accepts a single type argument. At runtime, functions marked this way should return a boolean and take at least one positional argument.

TypeIs aims to benefit type narrowing – a technique used by static type checkers to determine a more precise type of an expression within a program’s code flow. Usually type narrowing is done by analyzing conditional code flow and applying the narrowing to a block of code. The conditional expression here is sometimes referred to as a “type predicate”:

def is_str(val: str | float):
    # "isinstance" type predicate
    if isinstance(val, str):
        # Type of ``val`` is narrowed to ``str``
        ...
    else:
        # Else, type of ``val`` is narrowed to ``float``.
        ...

Sometimes it would be convenient to use a user-defined boolean function as a type predicate. Such a function should use TypeIs[...] or TypeGuard as its return type to alert static type checkers to this intention. TypeIs usually has more intuitive behavior than TypeGuard, but it cannot be used when the input and output types are incompatible (e.g., list[object] to list[int]) or when the function does not return True for all instances of the narrowed type.

Using -> TypeIs[NarrowedType] tells the static type checker that for a given function:

The return value is a boolean.

If the return value is True, the type of its argument is the intersection of the argument’s original type and NarrowedType.

If the return value is False, the type of its argument is narrowed to exclude NarrowedType.

예를 들면:

from typing import assert_type, final, TypeIs

class Parent: pass
class Child(Parent): pass
@final
class Unrelated: pass

def is_parent(val: object) -> TypeIs[Parent]:
    return isinstance(val, Parent)

def run(arg: Child | Unrelated):
    if is_parent(arg):
        # Type of ``arg`` is narrowed to the intersection
        # of ``Parent`` and ``Child``, which is equivalent to
        # ``Child``.
        assert_type(arg, Child)
    else:
        # Type of ``arg`` is narrowed to exclude ``Parent``,
        # so only ``Unrelated`` is left.
        assert_type(arg, Unrelated)

The type inside TypeIs must be consistent with the type of the function’s argument; if it is not, static type checkers will raise an error. An incorrectly written TypeIs function can lead to unsound behavior in the type system; it is the user’s responsibility to write such functions in a type-safe manner.

If a TypeIs function is a class or instance method, then the type in TypeIs maps to the type of the second parameter (after cls or self).

In short, the form def foo(arg: TypeA) -> TypeIs[TypeB]: ..., means that if foo(arg) returns True, then arg is an instance of TypeB, and if it returns False, it is not an instance of TypeB.

TypeIs also works with type variables. For more information, see PEP 742 [https://peps.python.org/pep-0742/] (Narrowing types with TypeIs).

Added in version 3.13.

typing.TypeGuard

Special typing construct for marking user-defined type predicate functions.

Type predicate functions are user-defined functions that return whether their argument is an instance of a particular type. TypeGuard works similarly to TypeIs, but has subtly different effects on type checking behavior (see below).

Using -> TypeGuard tells the static type checker that for a given function:

The return value is a boolean.

If the return value is True, the type of its argument is the type inside TypeGuard.

TypeGuard also works with type variables. See PEP 647 [https://peps.python.org/pep-0647/] for more details.

예를 들면:

def is_str_list(val: list[object]) -> TypeGuard[list[str]]:
    '''Determines whether all objects in the list are strings'''
    return all(isinstance(x, str) for x in val)

def func1(val: list[object]):
    if is_str_list(val):
        # Type of ``val`` is narrowed to ``list[str]``.
        print(" ".join(val))
    else:
        # Type of ``val`` remains as ``list[object]``.
        print("Not a list of strings!")

TypeIs and TypeGuard differ in the following ways:

TypeIs requires the narrowed type to be a subtype of the input type, while TypeGuard does not. The main reason is to allow for things like narrowing list[object] to list[str] even though the latter is not a subtype of the former, since list is invariant.

When a TypeGuard function returns True, type checkers narrow the type of the variable to exactly the TypeGuard type. When a TypeIs function returns True, type checkers can infer a more precise type combining the previously known type of the variable with the TypeIs type. (Technically, this is known as an intersection type.)

When a TypeGuard function returns False, type checkers cannot narrow the type of the variable at all. When a TypeIs function returns False, type checkers can narrow the type of the variable to exclude the TypeIs type.

Added in version 3.10.

typing.Unpack

Typing operator to conceptually mark an object as having been unpacked.

For example, using the unpack operator * on a type variable tuple is equivalent to using Unpack to mark the type variable tuple as having been unpacked:

Ts = TypeVarTuple('Ts')
tup: tuple[*Ts]
# Effectively does:
tup: tuple[Unpack[Ts]]

In fact, Unpack can be used interchangeably with * in the context of typing.TypeVarTuple and builtins.tuple types. You might see Unpack being used explicitly in older versions of Python, where * couldn’t be used in certain places:

# In older versions of Python, TypeVarTuple and Unpack
# are located in the `typing_extensions` backports package.
from typing_extensions import TypeVarTuple, Unpack

Ts = TypeVarTuple('Ts')
tup: tuple[*Ts]         # Syntax error on Python <= 3.10!
tup: tuple[Unpack[Ts]]  # Semantically equivalent, and backwards-compatible

Unpack can also be used along with typing.TypedDict for typing **kwargs in a function signature:

from typing import TypedDict, Unpack

class Movie(TypedDict):
    name: str
    year: int

# This function expects two keyword arguments - `name` of type `str`
# and `year` of type `int`.
def foo(**kwargs: Unpack[Movie]): ...

See PEP 692 [https://peps.python.org/pep-0692/] for more details on using Unpack for **kwargs typing.

Added in version 3.11.

Building generic types and type aliases

The following classes should not be used directly as annotations. Their intended purpose is to be building blocks for creating generic types and type aliases.

These objects can be created through special syntax (type parameter lists and the type statement). For compatibility with Python 3.11 and earlier, they can also be created without the dedicated syntax, as documented below.

class typing.Generic

제네릭 형을 위한 추상 베이스 클래스.

A generic type is typically declared by adding a list of type parameters after the class name:

class Mapping[KT, VT]:
    def __getitem__(self, key: KT) -> VT:
        ...
        # Etc.

Such a class implicitly inherits from Generic. The runtime semantics of this syntax are discussed in the Language Reference.

이 클래스는 다음과 같이 사용할 수 있습니다:

def lookup_name[X, Y](mapping: Mapping[X, Y], key: X, default: Y) -> Y:
    try:
        return mapping[key]
    except KeyError:
        return default

Here the brackets after the function name indicate a generic function.

For backwards compatibility, generic classes can also be declared by explicitly inheriting from Generic. In this case, the type parameters must be declared separately:

KT = TypeVar('KT')
VT = TypeVar('VT')

class Mapping(Generic[KT, VT]):
    def __getitem__(self, key: KT) -> VT:
        ...
        # Etc.

class typing.TypeVar(name, *constraints, bound=None, covariant=False, contravariant=False, infer_variance=False, default=typing.NoDefault)

형 변수.

The preferred way to construct a type variable is via the dedicated syntax for generic functions, generic classes, and generic type aliases:

class Sequence[T]:  # T is a TypeVar
    ...

This syntax can also be used to create bounded and constrained type variables:

class StrSequence[S: str]:  # S is a TypeVar with a `str` upper bound;
    ...                     # we can say that S is "bounded by `str`"

class StrOrBytesSequence[A: (str, bytes)]:  # A is a TypeVar constrained to str or bytes
    ...

However, if desired, reusable type variables can also be constructed manually, like so:

T = TypeVar('T')  # Can be anything
S = TypeVar('S', bound=str)  # Can be any subtype of str
A = TypeVar('A', str, bytes)  # Must be exactly str or bytes

Type variables exist primarily for the benefit of static type checkers. They serve as the parameters for generic types as well as for generic function and type alias definitions. See Generic for more information on generic types. Generic functions work as follows:

def repeat[T](x: T, n: int) -> Sequence[T]:
    """Return a list containing n references to x."""
    return [x]*n

def print_capitalized[S: str](x: S) -> S:
    """Print x capitalized, and return x."""
    print(x.capitalize())
    return x

def concatenate[A: (str, bytes)](x: A, y: A) -> A:
    """Add two strings or bytes objects together."""
    return x + y

Note that type variables can be bounded, constrained, or neither, but cannot be both bounded and constrained.

The variance of type variables is inferred by type checkers when they are created through the type parameter syntax or when infer_variance=True is passed. Manually created type variables may be explicitly marked covariant or contravariant by passing covariant=True or contravariant=True. By default, manually created type variables are invariant. See PEP 484 [https://peps.python.org/pep-0484/] and PEP 695 [https://peps.python.org/pep-0695/] for more details.

Bounded type variables and constrained type variables have different semantics in several important ways. Using a bounded type variable means that the TypeVar will be solved using the most specific type possible:

x = print_capitalized('a string')
reveal_type(x)  # revealed type is str

class StringSubclass(str):
    pass

y = print_capitalized(StringSubclass('another string'))
reveal_type(y)  # revealed type is StringSubclass

z = print_capitalized(45)  # error: int is not a subtype of str

The upper bound of a type variable can be a concrete type, abstract type (ABC or Protocol), or even a union of types:

# Can be anything with an __abs__ method
def print_abs[T: SupportsAbs](arg: T) -> None:
    print("Absolute value:", abs(arg))

U = TypeVar('U', bound=str|bytes)  # Can be any subtype of the union str|bytes
V = TypeVar('V', bound=SupportsAbs)  # Can be anything with an __abs__ method

Using a constrained type variable, however, means that the TypeVar can only ever be solved as being exactly one of the constraints given:

a = concatenate('one', 'two')
reveal_type(a)  # revealed type is str

b = concatenate(StringSubclass('one'), StringSubclass('two'))
reveal_type(b)  # revealed type is str, despite StringSubclass being passed in

c = concatenate('one', b'two')  # error: type variable 'A' can be either str or bytes in a function call, but not both

At runtime, isinstance(x, T) will raise TypeError.

__name__

The name of the type variable.

__covariant__

Whether the type var has been explicitly marked as covariant.

__contravariant__

Whether the type var has been explicitly marked as contravariant.

__infer_variance__

Whether the type variable’s variance should be inferred by type checkers.

Added in version 3.12.

__bound__

The upper bound of the type variable, if any.

버전 3.12에서 변경: For type variables created through type parameter syntax, the bound is evaluated only when the attribute is accessed, not when the type variable is created (see Lazy evaluation).

evaluate_bound()

An evaluate function corresponding to the __bound__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __bound__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format.

Added in version 3.14.

__constraints__

A tuple containing the constraints of the type variable, if any.

버전 3.12에서 변경: For type variables created through type parameter syntax, the constraints are evaluated only when the attribute is accessed, not when the type variable is created (see Lazy evaluation).

evaluate_constraints()

An evaluate function corresponding to the __constraints__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __constraints__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format.

Added in version 3.14.

__default__

The default value of the type variable, or typing.NoDefault if it has no default.

Added in version 3.13.

evaluate_default()

An evaluate function corresponding to the __default__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __default__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format.

Added in version 3.14.

has_default()

Return whether or not the type variable has a default value. This is equivalent to checking whether __default__ is not the typing.NoDefault singleton, except that it does not force evaluation of the lazily evaluated default value.

Added in version 3.13.

버전 3.12에서 변경: Type variables can now be declared using the type parameter syntax introduced by PEP 695 [https://peps.python.org/pep-0695/]. The infer_variance parameter was added.

버전 3.13에서 변경: Support for default values was added.

class typing.TypeVarTuple(name, *, default=typing.NoDefault)

Type variable tuple. A specialized form of type variable that enables variadic generics.

Type variable tuples can be declared in type parameter lists using a single asterisk (*) before the name:

def move_first_element_to_last[T, *Ts](tup: tuple[T, *Ts]) -> tuple[*Ts, T]:
    return (*tup[1:], tup[0])

Or by explicitly invoking the TypeVarTuple constructor:

T = TypeVar("T")
Ts = TypeVarTuple("Ts")

def move_first_element_to_last(tup: tuple[T, *Ts]) -> tuple[*Ts, T]:
    return (*tup[1:], tup[0])

A normal type variable enables parameterization with a single type. A type variable tuple, in contrast, allows parameterization with an arbitrary number of types by acting like an arbitrary number of type variables wrapped in a tuple. For example:

# T is bound to int, Ts is bound to ()
# Return value is (1,), which has type tuple[int]
move_first_element_to_last(tup=(1,))

# T is bound to int, Ts is bound to (str,)
# Return value is ('spam', 1), which has type tuple[str, int]
move_first_element_to_last(tup=(1, 'spam'))

# T is bound to int, Ts is bound to (str, float)
# Return value is ('spam', 3.0, 1), which has type tuple[str, float, int]
move_first_element_to_last(tup=(1, 'spam', 3.0))

# This fails to type check (and fails at runtime)
# because tuple[()] is not compatible with tuple[T, *Ts]
# (at least one element is required)
move_first_element_to_last(tup=())

Note the use of the unpacking operator * in tuple[T, *Ts]. Conceptually, you can think of Ts as a tuple of type variables (T1, T2, ...). tuple[T, *Ts] would then become tuple[T, *(T1, T2, ...)], which is equivalent to tuple[T, T1, T2, ...]. (Note that in older versions of Python, you might see this written using Unpack instead, as Unpack[Ts].)

Type variable tuples must always be unpacked. This helps distinguish type variable tuples from normal type variables:

x: Ts          # Not valid
x: tuple[Ts]   # Not valid
x: tuple[*Ts]  # The correct way to do it

Type variable tuples can be used in the same contexts as normal type variables. For example, in class definitions, arguments, and return types:

class Array[*Shape]:
    def __getitem__(self, key: tuple[*Shape]) -> float: ...
    def __abs__(self) -> "Array[*Shape]": ...
    def get_shape(self) -> tuple[*Shape]: ...

Type variable tuples can be happily combined with normal type variables:

class Array[DType, *Shape]:  # This is fine
    pass

class Array2[*Shape, DType]:  # This would also be fine
    pass

class Height: ...
class Width: ...

float_array_1d: Array[float, Height] = Array()     # Totally fine
int_array_2d: Array[int, Height, Width] = Array()  # Yup, fine too

However, note that at most one type variable tuple may appear in a single list of type arguments or type parameters:

x: tuple[*Ts, *Ts]            # Not valid
class Array[*Shape, *Shape]:  # Not valid
    pass

Finally, an unpacked type variable tuple can be used as the type annotation of *args:

def call_soon[*Ts](
    callback: Callable[[*Ts], None],
    *args: *Ts
) -> None:
    ...
    callback(*args)

In contrast to non-unpacked annotations of *args - e.g. *args: int, which would specify that all arguments are int - *args: *Ts enables reference to the types of the individual arguments in *args. Here, this allows us to ensure the types of the *args passed to call_soon match the types of the (positional) arguments of callback.

See PEP 646 [https://peps.python.org/pep-0646/] for more details on type variable tuples.

__name__

The name of the type variable tuple.

__default__

The default value of the type variable tuple, or typing.NoDefault if it has no default.

Added in version 3.13.

evaluate_default()

An evaluate function corresponding to the __default__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __default__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format.

Added in version 3.14.

has_default()

Return whether or not the type variable tuple has a default value. This is equivalent to checking whether __default__ is not the typing.NoDefault singleton, except that it does not force evaluation of the lazily evaluated default value.

Added in version 3.13.

Added in version 3.11.

버전 3.12에서 변경: Type variable tuples can now be declared using the type parameter syntax introduced by PEP 695 [https://peps.python.org/pep-0695/].

버전 3.13에서 변경: Support for default values was added.

class typing.ParamSpec(name, *, bound=None, covariant=False, contravariant=False, default=typing.NoDefault)

Parameter specification variable. A specialized version of type variables.

In type parameter lists, parameter specifications can be declared with two asterisks (**):

type IntFunc[**P] = Callable[P, int]

For compatibility with Python 3.11 and earlier, ParamSpec objects can also be created as follows:

P = ParamSpec('P')

Parameter specification variables exist primarily for the benefit of static type checkers. They are used to forward the parameter types of one callable to another callable – a pattern commonly found in higher order functions and decorators. They are only valid when used in Concatenate, or as the first argument to Callable, or as parameters for user-defined Generics. See Generic for more information on generic types.

For example, to add basic logging to a function, one can create a decorator add_logging to log function calls. The parameter specification variable tells the type checker that the callable passed into the decorator and the new callable returned by it have inter-dependent type parameters:

from collections.abc import Callable
import logging

def add_logging[T, **P](f: Callable[P, T]) -> Callable[P, T]:
    '''A type-safe decorator to add logging to a function.'''
    def inner(*args: P.args, **kwargs: P.kwargs) -> T:
        logging.info(f'{f.__name__} was called')
        return f(*args, **kwargs)
    return inner

@add_logging
def add_two(x: float, y: float) -> float:
    '''Add two numbers together.'''
    return x + y

Without ParamSpec, the simplest way to annotate this previously was to use a TypeVar with upper bound Callable[..., Any]. However this causes two problems:

The type checker can’t type check the inner function because *args and **kwargs have to be typed Any.

cast() may be required in the body of the add_logging decorator when returning the inner function, or the static type checker must be told to ignore the return inner.

args

kwargs

Since ParamSpec captures both positional and keyword parameters, P.args and P.kwargs can be used to split a ParamSpec into its components. P.args represents the tuple of positional parameters in a given call and should only be used to annotate *args. P.kwargs represents the mapping of keyword parameters to their values in a given call, and should be only be used to annotate **kwargs. Both attributes require the annotated parameter to be in scope. At runtime, P.args and P.kwargs are instances respectively of ParamSpecArgs and ParamSpecKwargs.

__name__

The name of the parameter specification.

__default__

The default value of the parameter specification, or typing.NoDefault if it has no default.

Added in version 3.13.

evaluate_default()

An evaluate function corresponding to the __default__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __default__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format.

Added in version 3.14.

has_default()

Return whether or not the parameter specification has a default value. This is equivalent to checking whether __default__ is not the typing.NoDefault singleton, except that it does not force evaluation of the lazily evaluated default value.

Added in version 3.13.

Parameter specification variables created with covariant=True or contravariant=True can be used to declare covariant or contravariant generic types. The bound argument is also accepted, similar to TypeVar. However the actual semantics of these keywords are yet to be decided.

Added in version 3.10.

버전 3.12에서 변경: Parameter specifications can now be declared using the type parameter syntax introduced by PEP 695 [https://peps.python.org/pep-0695/].

버전 3.13에서 변경: Support for default values was added.

참고

Only parameter specification variables defined in global scope can be pickled.

더 보기

PEP 612 [https://peps.python.org/pep-0612/] – Parameter Specification Variables (the PEP which introduced ParamSpec and Concatenate)

Concatenate

Annotating callable objects

typing.ParamSpecArgs

typing.ParamSpecKwargs

Arguments and keyword arguments attributes of a ParamSpec. The P.args attribute of a ParamSpec is an instance of ParamSpecArgs, and P.kwargs is an instance of ParamSpecKwargs. They are intended for runtime introspection and have no special meaning to static type checkers.

Calling get_origin() on either of these objects will return the original ParamSpec:

>>> from typing import ParamSpec, get_origin
>>> P = ParamSpec("P")
>>> get_origin(P.args) is P
True
>>> get_origin(P.kwargs) is P
True

Added in version 3.10.

class typing.TypeAliasType(name, value, *, type_params=())

The type of type aliases created through the type statement.

Example:

>>> type Alias = int
>>> type(Alias)
<class 'typing.TypeAliasType'>

Added in version 3.12.

__name__

The name of the type alias:

>>> type Alias = int
>>> Alias.__name__
'Alias'

__module__

The module in which the type alias was defined:

>>> type Alias = int
>>> Alias.__module__
'__main__'

__type_params__

The type parameters of the type alias, or an empty tuple if the alias is not generic:

>>> type ListOrSet[T] = list[T] | set[T]
>>> ListOrSet.__type_params__
(T,)
>>> type NotGeneric = int
>>> NotGeneric.__type_params__
()

__value__

The type alias’s value. This is lazily evaluated, so names used in the definition of the alias are not resolved until the __value__ attribute is accessed:

>>> type Mutually = Recursive
>>> type Recursive = Mutually
>>> Mutually
Mutually
>>> Recursive
Recursive
>>> Mutually.__value__
Recursive
>>> Recursive.__value__
Mutually

evaluate_value()

An evaluate function corresponding to the __value__ attribute. When called directly, this method supports only the VALUE format, which is equivalent to accessing the __value__ attribute directly, but the method object can be passed to annotationlib.call_evaluate_function() to evaluate the value in a different format:

>>> type Alias = undefined
>>> Alias.__value__
Traceback (most recent call last):
...
NameError: name 'undefined' is not defined
>>> from annotationlib import Format, call_evaluate_function
>>> Alias.evaluate_value(Format.VALUE)
Traceback (most recent call last):
...
NameError: name 'undefined' is not defined
>>> call_evaluate_function(Alias.evaluate_value, Format.FORWARDREF)
ForwardRef('undefined')

Added in version 3.14.

기타 특수 지시자

These functions and classes should not be used directly as annotations. Their intended purpose is to be building blocks for creating and declaring types.

class typing.NamedTuple

형 지정된(typed) collections.namedtuple() 버전.

용법:

class Employee(NamedTuple):
    name: str
    id: int

이것은 다음과 동등합니다:

Employee = collections.namedtuple('Employee', ['name', 'id'])

필드에 기본값을 부여하려면, 클래스 바디에서 그 값을 대입할 수 있습니다:

class Employee(NamedTuple):
    name: str
    id: int = 3

employee = Employee('Guido')
assert employee.id == 3

기본값이 있는 필드는 기본값이 없는 모든 필드 뒤에 와야 합니다.

The resulting class has an extra attribute __annotations__ giving a dict that maps the field names to the field types. (The field names are in the _fields attribute and the default values are in the _field_defaults attribute, both of which are part of the namedtuple() API.)

NamedTuple 서브 클래스는 독스트링과 메서드도 가질 수 있습니다:

class Employee(NamedTuple):
    """Represents an employee."""
    name: str
    id: int = 3

    def __repr__(self) -> str:
        return f'<Employee {self.name}, id={self.id}>'

NamedTuple subclasses can be generic:

class Group[T](NamedTuple):
    key: T
    group: list[T]

이전 버전과 호환되는 사용법:

# For creating a generic NamedTuple on Python 3.11
T = TypeVar("T")

class Group(NamedTuple, Generic[T]):
    key: T
    group: list[T]

# A functional syntax is also supported
Employee = NamedTuple('Employee', [('name', str), ('id', int)])

버전 3.6에서 변경: PEP 526 [https://peps.python.org/pep-0526/] 변수 어노테이션 문법 지원을 추가했습니다.

버전 3.6.1에서 변경: 기본값, 메서드 및 독스트링에 대한 지원을 추가했습니다.

버전 3.8에서 변경: _field_types와 __annotations__ 어트리뷰트는 이제 OrderedDict 인스턴스가 아닌 일반 딕셔너리입니다.

버전 3.9에서 변경: _field_types 어트리뷰트를 제거하고, 같은 정보를 가지는 더 표준적인 __annotations__ 어트리뷰트로 대체했습니다.

버전 3.11에서 변경: Added support for generic namedtuples.

Deprecated since version 3.13, will be removed in version 3.15: The undocumented keyword argument syntax for creating NamedTuple classes (NT = NamedTuple("NT", x=int)) is deprecated, and will be disallowed in 3.15. Use the class-based syntax or the functional syntax instead.

Deprecated since version 3.13, will be removed in version 3.15: When using the functional syntax to create a NamedTuple class, failing to pass a value to the ‘fields’ parameter (NT = NamedTuple("NT")) is deprecated. Passing None to the ‘fields’ parameter (NT = NamedTuple("NT", None)) is also deprecated. Both will be disallowed in Python 3.15. To create a NamedTuple class with 0 fields, use class NT(NamedTuple): pass or NT = NamedTuple("NT", []).

class typing.NewType(name, tp)

Helper class to create low-overhead distinct types.

A NewType is considered a distinct type by a typechecker. At runtime, however, calling a NewType returns its argument unchanged.

용법:

UserId = NewType('UserId', int)  # Declare the NewType "UserId"
first_user = UserId(1)  # "UserId" returns the argument unchanged at runtime

__module__

The module in which the new type is defined.

__name__

The name of the new type.

__supertype__

The type that the new type is based on.

Added in version 3.5.2.

버전 3.10에서 변경: NewType is now a class rather than a function.

class typing.Protocol(Generic)

Base class for protocol classes.

Protocol classes are defined like this:

class Proto(Protocol):
    def meth(self) -> int:
        ...

이러한 클래스는 주로 구조적 서브 타이핑(정적 덕 타이핑)을 인식하는 정적 형 검사기와 함께 사용됩니다, 예를 들어:

class C:
    def meth(self) -> int:
        return 0

def func(x: Proto) -> int:
    return x.meth()

func(C())  # Passes static type check

See PEP 544 [https://peps.python.org/pep-0544/] for more details. Protocol classes decorated with runtime_checkable() (described later) act as simple-minded runtime protocols that check only the presence of given attributes, ignoring their type signatures.

프로토콜 클래스는 제네릭일 수 있습니다, 예를 들어:

class GenProto[T](Protocol):
    def meth(self) -> T:
        ...

In code that needs to be compatible with Python 3.11 or older, generic Protocols can be written as follows:

T = TypeVar("T")

class GenProto(Protocol[T]):
    def meth(self) -> T:
        ...

Added in version 3.8.

@typing.runtime_checkable

프로토콜 클래스를 실행 시간 프로토콜로 표시합니다.

이러한 프로토콜은 isinstance()와 issubclass()와 함께 사용할 수 있습니다. 이것은 비 프로토콜 클래스에 적용될 때 TypeError를 발생시킵니다. 이것은 collections.abc에 있는 Iterable처럼 “한 가지만 잘하는” 것과 매우 유사한 단순한 구조적 검사를 허용합니다. 예를 들면:

@runtime_checkable
class Closable(Protocol):
    def close(self): ...

assert isinstance(open('/some/file'), Closable)

@runtime_checkable
class Named(Protocol):
    name: str

import threading
assert isinstance(threading.Thread(name='Bob'), Named)

참고

runtime_checkable() will check only the presence of the required methods or attributes, not their type signatures or types. For example, ssl.SSLObject is a class, therefore it passes an issubclass() check against Callable. However, the ssl.SSLObject.__init__ method exists only to raise a TypeError with a more informative message, therefore making it impossible to call (instantiate) ssl.SSLObject.

참고

An isinstance() check against a runtime-checkable protocol can be surprisingly slow compared to an isinstance() check against a non-protocol class. Consider using alternative idioms such as hasattr() calls for structural checks in performance-sensitive code.

Added in version 3.8.

버전 3.12에서 변경: The internal implementation of isinstance() checks against runtime-checkable protocols now uses inspect.getattr_static() to look up attributes (previously, hasattr() was used). As a result, some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change.

버전 3.12에서 변경: The members of a runtime-checkable protocol are now considered “frozen” at runtime as soon as the class has been created. Monkey-patching attributes onto a runtime-checkable protocol will still work, but will have no impact on isinstance() checks comparing objects to the protocol. See “What’s new in Python 3.12” for more details.

class typing.TypedDict(dict)

딕셔너리에 형 힌트를 추가하는 특수 구조. 실행 시간에 일반 dict입니다.

TypedDict는 모든 인스턴스가 각 키가 일관된 형의 값에 연관되는, 특정한 키 집합을 갖도록 기대되는 딕셔너리 형을 선언합니다. 이 기대는 실행 시간에는 검사되지 않고, 형 검사기에서만 강제됩니다. 사용법:

class Point2D(TypedDict):
    x: int
    y: int
    label: str

a: Point2D = {'x': 1, 'y': 2, 'label': 'good'}  # OK
b: Point2D = {'z': 3, 'label': 'bad'}           # Fails type check

assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')

An alternative way to create a TypedDict is by using function-call syntax. The second argument must be a literal dict:

Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})

This functional syntax allows defining keys which are not valid identifiers, for example because they are keywords or contain hyphens:

# raises SyntaxError
class Point2D(TypedDict):
    in: int  # 'in' is a keyword
    x-y: int  # name with hyphens

# OK, functional syntax
Point2D = TypedDict('Point2D', {'in': int, 'x-y': int})

By default, all keys must be present in a TypedDict. It is possible to mark individual keys as non-required using NotRequired:

class Point2D(TypedDict):
    x: int
    y: int
    label: NotRequired[str]

# Alternative syntax
Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': NotRequired[str]})

This means that a Point2D TypedDict can have the label key omitted.

It is also possible to mark all keys as non-required by default by specifying a totality of False:

class Point2D(TypedDict, total=False):
    x: int
    y: int

# Alternative syntax
Point2D = TypedDict('Point2D', {'x': int, 'y': int}, total=False)

This means that a Point2D TypedDict can have any of the keys omitted. A type checker is only expected to support a literal False or True as the value of the total argument. True is the default, and makes all items defined in the class body required.

Individual keys of a total=False TypedDict can be marked as required using Required:

class Point2D(TypedDict, total=False):
    x: Required[int]
    y: Required[int]
    label: str

# Alternative syntax
Point2D = TypedDict('Point2D', {
    'x': Required[int],
    'y': Required[int],
    'label': str
}, total=False)

It is possible for a TypedDict type to inherit from one or more other TypedDict types using the class-based syntax. Usage:

class Point3D(Point2D):
    z: int

Point3D has three items: x, y and z. It is equivalent to this definition:

class Point3D(TypedDict):
    x: int
    y: int
    z: int

A TypedDict cannot inherit from a non-TypedDict class, except for Generic. For example:

class X(TypedDict):
    x: int

class Y(TypedDict):
    y: int

class Z(object): pass  # A non-TypedDict class

class XY(X, Y): pass  # OK

class XZ(X, Z): pass  # raises TypeError

A TypedDict can be generic:

class Group[T](TypedDict):
    key: T
    group: list[T]

To create a generic TypedDict that is compatible with Python 3.11 or lower, inherit from Generic explicitly:

T = TypeVar("T")

class Group(TypedDict, Generic[T]):
    key: T
    group: list[T]

A TypedDict can be introspected via annotations dicts (see Annotations Best Practices for more information on annotations best practices), __total__, __required_keys__, and __optional_keys__.

__total__

Point2D.__total__ gives the value of the total argument. Example:

>>> from typing import TypedDict
>>> class Point2D(TypedDict): pass
>>> Point2D.__total__
True
>>> class Point2D(TypedDict, total=False): pass
>>> Point2D.__total__
False
>>> class Point3D(Point2D): pass
>>> Point3D.__total__
True

This attribute reflects only the value of the total argument to the current TypedDict class, not whether the class is semantically total. For example, a TypedDict with __total__ set to True may have keys marked with NotRequired, or it may inherit from another TypedDict with total=False. Therefore, it is generally better to use __required_keys__ and __optional_keys__ for introspection.

__required_keys__

Added in version 3.9.

__optional_keys__

Point2D.__required_keys__ and Point2D.__optional_keys__ return frozenset objects containing required and non-required keys, respectively.

Keys marked with Required will always appear in __required_keys__ and keys marked with NotRequired will always appear in __optional_keys__.

For backwards compatibility with Python 3.10 and below, it is also possible to use inheritance to declare both required and non-required keys in the same TypedDict . This is done by declaring a TypedDict with one value for the total argument and then inheriting from it in another TypedDict with a different value for total:

>>> class Point2D(TypedDict, total=False):
...     x: int
...     y: int
...
>>> class Point3D(Point2D):
...     z: int
...
>>> Point3D.__required_keys__ == frozenset({'z'})
True
>>> Point3D.__optional_keys__ == frozenset({'x', 'y'})
True

Added in version 3.9.

참고

If from __future__ import annotations is used or if annotations are given as strings, annotations are not evaluated when the TypedDict is defined. Therefore, the runtime introspection that __required_keys__ and __optional_keys__ rely on may not work properly, and the values of the attributes may be incorrect.

Support for ReadOnly is reflected in the following attributes:

__readonly_keys__

A frozenset containing the names of all read-only keys. Keys are read-only if they carry the ReadOnly qualifier.

Added in version 3.13.

__mutable_keys__

A frozenset containing the names of all mutable keys. Keys are mutable if they do not carry the ReadOnly qualifier.

Added in version 3.13.

추가 예제와 TypedDict를 사용하는 자세한 규칙은 PEP 589 [https://peps.python.org/pep-0589/]를 참조하십시오.

Added in version 3.8.

버전 3.11에서 변경: Added support for marking individual keys as Required or NotRequired. See PEP 655 [https://peps.python.org/pep-0655/].

버전 3.11에서 변경: Added support for generic TypedDicts.

버전 3.13에서 변경: Removed support for the keyword-argument method of creating TypedDicts.

버전 3.13에서 변경: Support for the ReadOnly qualifier was added.

Deprecated since version 3.13, will be removed in version 3.15: When using the functional syntax to create a TypedDict class, failing to pass a value to the ‘fields’ parameter (TD = TypedDict("TD")) is deprecated. Passing None to the ‘fields’ parameter (TD = TypedDict("TD", None)) is also deprecated. Both will be disallowed in Python 3.15. To create a TypedDict class with 0 fields, use class TD(TypedDict): pass or TD = TypedDict("TD", {}).

프로토콜

The following protocols are provided by the typing module. All are decorated with @runtime_checkable.

class typing.SupportsAbs

반환형이 공변적(covariant)인 하나의 추상 메서드 __abs__를 가진 ABC.

class typing.SupportsBytes

하나의 추상 메서드 __bytes__를 가진 ABC.

class typing.SupportsComplex

하나의 추상 메서드 __complex__를 가진 ABC.

class typing.SupportsFloat

하나의 추상 메서드 __float__를 가진 ABC.

class typing.SupportsIndex

하나의 추상 메서드 __index__를 가진 ABC.

Added in version 3.8.

class typing.SupportsInt

하나의 추상 메서드 __int__를 가진 ABC.

class typing.SupportsRound

반환형이 공변적(covariant)인 하나의 추상 메서드 __round__를 가진 ABC.

ABCs for working with IO

class typing.IO

class typing.TextIO

class typing.BinaryIO

Generic type IO[AnyStr] and its subclasses TextIO(IO[str]) and BinaryIO(IO[bytes]) represent the types of I/O streams such as returned by open().

함수와 데코레이터

typing.cast(typ, val)

값을 형으로 변환합니다.

값을 변경하지 않고 반환합니다. 형 검사기에서는 반환 값이 지정된 형임을 나타내지만, 실행 시간에는 의도적으로 아무것도 확인하지 않습니다 (우리는 이것이 가능한 한 빠르기를 원합니다).

typing.assert_type(val, typ, /)

Ask a static type checker to confirm that val has an inferred type of typ.

At runtime this does nothing: it returns the first argument unchanged with no checks or side effects, no matter the actual type of the argument.

When a static type checker encounters a call to assert_type(), it emits an error if the value is not of the specified type:

def greet(name: str) -> None:
    assert_type(name, str)  # OK, inferred type of `name` is `str`
    assert_type(name, int)  # type checker error

This function is useful for ensuring the type checker’s understanding of a script is in line with the developer’s intentions:

def complex_function(arg: object):
    # Do some complex type-narrowing logic,
    # after which we hope the inferred type will be `int`
    ...
    # Test whether the type checker correctly understands our function
    assert_type(arg, int)

Added in version 3.11.

typing.assert_never(arg, /)

Ask a static type checker to confirm that a line of code is unreachable.

Example:

def int_or_str(arg: int | str) -> None:
    match arg:
        case int():
            print("It's an int")
        case str():
            print("It's a str")
        case _ as unreachable:
            assert_never(unreachable)

Here, the annotations allow the type checker to infer that the last case can never execute, because arg is either an int or a str, and both options are covered by earlier cases.

If a type checker finds that a call to assert_never() is reachable, it will emit an error. For example, if the type annotation for arg was instead int | str | float, the type checker would emit an error pointing out that unreachable is of type float. For a call to assert_never to pass type checking, the inferred type of the argument passed in must be the bottom type, Never, and nothing else.

At runtime, this throws an exception when called.

더 보기

Unreachable Code and Exhaustiveness Checking [https://typing.readthedocs.io/en/latest/guides/unreachable.html] has more information about exhaustiveness checking with static typing.

Added in version 3.11.

typing.reveal_type(obj, /)

Ask a static type checker to reveal the inferred type of an expression.

When a static type checker encounters a call to this function, it emits a diagnostic with the inferred type of the argument. For example:

x: int = 1
reveal_type(x)  # Revealed type is "builtins.int"

This can be useful when you want to debug how your type checker handles a particular piece of code.

At runtime, this function prints the runtime type of its argument to sys.stderr and returns the argument unchanged (allowing the call to be used within an expression):

x = reveal_type(1)  # prints "Runtime type is int"
print(x)  # prints "1"

Note that the runtime type may be different from (more or less specific than) the type statically inferred by a type checker.

Most type checkers support reveal_type() anywhere, even if the name is not imported from typing. Importing the name from typing, however, allows your code to run without runtime errors and communicates intent more clearly.

Added in version 3.11.

@typing.dataclass_transform(*, eq_default=True, order_default=False, kw_only_default=False, frozen_default=False, field_specifiers=(), **kwargs)

Decorator to mark an object as providing dataclass-like behavior.

dataclass_transform may be used to decorate a class, metaclass, or a function that is itself a decorator. The presence of @dataclass_transform() tells a static type checker that the decorated object performs runtime “magic” that transforms a class in a similar way to @dataclasses.dataclass.

Example usage with a decorator function:

@dataclass_transform()
def create_model[T](cls: type[T]) -> type[T]:
    ...
    return cls

@create_model
class CustomerModel:
    id: int
    name: str

On a base class:

@dataclass_transform()
class ModelBase: ...

class CustomerModel(ModelBase):
    id: int
    name: str

On a metaclass:

@dataclass_transform()
class ModelMeta(type): ...

class ModelBase(metaclass=ModelMeta): ...

class CustomerModel(ModelBase):
    id: int
    name: str

The CustomerModel classes defined above will be treated by type checkers similarly to classes created with @dataclasses.dataclass. For example, type checkers will assume these classes have __init__ methods that accept id and name.

The decorated class, metaclass, or function may accept the following bool arguments which type checkers will assume have the same effect as they would have on the @dataclasses.dataclass decorator: init, eq, order, unsafe_hash, frozen, match_args, kw_only, and slots. It must be possible for the value of these arguments (True or False) to be statically evaluated.

The arguments to the dataclass_transform decorator can be used to customize the default behaviors of the decorated class, metaclass, or function:

매개변수:

eq_default (bool) – Indicates whether the eq parameter is assumed to be True or False if it is omitted by the caller. Defaults to True.

order_default (bool) – Indicates whether the order parameter is assumed to be True or False if it is omitted by the caller. Defaults to False.

kw_only_default (bool) – Indicates whether the kw_only parameter is assumed to be True or False if it is omitted by the caller. Defaults to False.

frozen_default (bool) –

Indicates whether the frozen parameter is assumed to be True or False if it is omitted by the caller. Defaults to False.

Added in version 3.12.

field_specifiers (tuple[Callable[..., Any], ...]) – Specifies a static list of supported classes or functions that describe fields, similar to dataclasses.field(). Defaults to ().

**kwargs (Any) – Arbitrary other keyword arguments are accepted in order to allow for possible future extensions.

Type checkers recognize the following optional parameters on field specifiers:

Recognised parameters for field specifiers

Parameter name

Description

init

Indicates whether the field should be included in the synthesized __init__ method. If unspecified, init defaults to True.

default

Provides the default value for the field.

default_factory

Provides a runtime callback that returns the default value for the field. If neither default nor default_factory are specified, the field is assumed to have no default value and must be provided a value when the class is instantiated.

factory

An alias for the default_factory parameter on field specifiers.

kw_only

Indicates whether the field should be marked as keyword-only. If True, the field will be keyword-only. If False, it will not be keyword-only. If unspecified, the value of the kw_only parameter on the object decorated with dataclass_transform will be used, or if that is unspecified, the value of kw_only_default on dataclass_transform will be used.

alias

Provides an alternative name for the field. This alternative name is used in the synthesized __init__ method.

At runtime, this decorator records its arguments in the __dataclass_transform__ attribute on the decorated object. It has no other runtime effect.

See PEP 681 [https://peps.python.org/pep-0681/] for more details.

Added in version 3.11.

@typing.overload

Decorator for creating overloaded functions and methods.

The @overload decorator allows describing functions and methods that support multiple different combinations of argument types. A series of @overload-decorated definitions must be followed by exactly one non-@overload-decorated definition (for the same function/method).

@overload-decorated definitions are for the benefit of the type checker only, since they will be overwritten by the non-@overload-decorated definition. The non-@overload-decorated definition, meanwhile, will be used at runtime but should be ignored by a type checker. At runtime, calling an @overload-decorated function directly will raise NotImplementedError.

An example of overload that gives a more precise type than can be expressed using a union or a type variable:

@overload
def process(response: None) -> None:
    ...
@overload
def process(response: int) -> tuple[int, str]:
    ...
@overload
def process(response: bytes) -> str:
    ...
def process(response):
    ...  # actual implementation goes here

See PEP 484 [https://peps.python.org/pep-0484/] for more details and comparison with other typing semantics.

버전 3.11에서 변경: Overloaded functions can now be introspected at runtime using get_overloads().

typing.get_overloads(func)

Return a sequence of @overload-decorated definitions for func.

func is the function object for the implementation of the overloaded function. For example, given the definition of process in the documentation for @overload, get_overloads(process) will return a sequence of three function objects for the three defined overloads. If called on a function with no overloads, get_overloads() returns an empty sequence.

get_overloads() can be used for introspecting an overloaded function at runtime.

Added in version 3.11.

typing.clear_overloads()

Clear all registered overloads in the internal registry.

This can be used to reclaim the memory used by the registry.

Added in version 3.11.

@typing.final

Decorator to indicate final methods and final classes.

Decorating a method with @final indicates to a type checker that the method cannot be overridden in a subclass. Decorating a class with @final indicates that it cannot be subclassed.

예를 들면:

class Base:
    @final
    def done(self) -> None:
        ...
class Sub(Base):
    def done(self) -> None:  # Error reported by type checker
        ...

@final
class Leaf:
    ...
class Other(Leaf):  # Error reported by type checker
    ...

이러한 속성에 대한 실행 시간 검사는 없습니다. 자세한 내용은 PEP 591 [https://peps.python.org/pep-0591/]을 참조하십시오.

Added in version 3.8.

버전 3.11에서 변경: The decorator will now attempt to set a __final__ attribute to True on the decorated object. Thus, a check like if getattr(obj, "__final__", False) can be used at runtime to determine whether an object obj has been marked as final. If the decorated object does not support setting attributes, the decorator returns the object unchanged without raising an exception.

@typing.no_type_check

어노테이션이 형 힌트가 아님을 나타내는 데코레이터.

This works as a class or function decorator. With a class, it applies recursively to all methods and classes defined in that class (but not to methods defined in its superclasses or subclasses). Type checkers will ignore all annotations in a function or class with this decorator.

@no_type_check mutates the decorated object in place.

@typing.no_type_check_decorator

다른 데코레이터에 no_type_check() 효과를 주는 데코레이터.

이것은 데코레이트 된 함수를 no_type_check()로 감싸는 무언가로 데코레이터를 감쌉니다.

Deprecated since version 3.13, will be removed in version 3.15: No type checker ever added support for @no_type_check_decorator. It is therefore deprecated, and will be removed in Python 3.15.

@typing.override

Decorator to indicate that a method in a subclass is intended to override a method or attribute in a superclass.

Type checkers should emit an error if a method decorated with @override does not, in fact, override anything. This helps prevent bugs that may occur when a base class is changed without an equivalent change to a child class.

For example:

class Base:
    def log_status(self) -> None:
        ...

class Sub(Base):
    @override
    def log_status(self) -> None:  # Okay: overrides Base.log_status
        ...

    @override
    def done(self) -> None:  # Error reported by type checker
        ...

There is no runtime checking of this property.

The decorator will attempt to set an __override__ attribute to True on the decorated object. Thus, a check like if getattr(obj, "__override__", False) can be used at runtime to determine whether an object obj has been marked as an override. If the decorated object does not support setting attributes, the decorator returns the object unchanged without raising an exception.

See PEP 698 [https://peps.python.org/pep-0698/] for more details.

Added in version 3.12.

@typing.type_check_only

Decorator to mark a class or function as unavailable at runtime.

이 데코레이터 자체는 실행 시간에 사용할 수 없습니다. 주로, 구현이 비공개 클래스의 인스턴스를 반환할 때, 형 스텁 파일에 정의된 클래스를 표시하기 위한 용도입니다:

@type_check_only
class Response:  # private or not available at runtime
    code: int
    def get_header(self, name: str) -> str: ...

def fetch_response() -> Response: ...

비공개 클래스의 인스턴스를 반환하는 것은 좋지 않음에 유의하십시오. 일반적으로 그러한 클래스를 공개로 만드는 것이 바람직합니다.

인트로스펙션 도우미

typing.get_type_hints(obj, globalns=None, localns=None, include_extras=False)

함수, 메서드, 모듈 또는 클래스 객체에 대한 형 힌트가 포함된 딕셔너리를 반환합니다.

This is often the same as obj.__annotations__, but this function makes the following changes to the annotations dictionary:

Forward references encoded as string literals or ForwardRef objects are handled by evaluating them in globalns, localns, and (where applicable) obj’s type parameter namespace. If globalns or localns is not given, appropriate namespace dictionaries are inferred from obj.

None is replaced with types.NoneType.

If @no_type_check has been applied to obj, an empty dictionary is returned.

If obj is a class C, the function returns a dictionary that merges annotations from C’s base classes with those on C directly. This is done by traversing C.__mro__ and iteratively combining __annotations__ dictionaries. Annotations on classes appearing earlier in the method resolution order always take precedence over annotations on classes appearing later in the method resolution order.

The function recursively replaces all occurrences of Annotated[T, ...] with T, unless include_extras is set to True (see Annotated for more information).

See also inspect.get_annotations(), a lower-level function that returns annotations more directly.

참고

If any forward references in the annotations of obj are not resolvable or are not valid Python code, this function will raise an exception such as NameError. For example, this can happen with imported type aliases that include forward references, or with names imported under if TYPE_CHECKING.

버전 3.9에서 변경: Added include_extras parameter as part of PEP 593 [https://peps.python.org/pep-0593/]. See the documentation on Annotated for more information.

버전 3.11에서 변경: Previously, Optional[t] was added for function and method annotations if a default value equal to None was set. Now the annotation is returned unchanged.

typing.get_origin(tp)

Get the unsubscripted version of a type: for a typing object of the form X[Y, Z, ...] return X.

If X is a typing-module alias for a builtin or collections class, it will be normalized to the original class. If X is an instance of ParamSpecArgs or ParamSpecKwargs, return the underlying ParamSpec. Return None for unsupported objects.

Examples:

assert get_origin(str) is None
assert get_origin(Dict[str, int]) is dict
assert get_origin(Union[int, str]) is Union
assert get_origin(Annotated[str, "metadata"]) is Annotated
P = ParamSpec('P')
assert get_origin(P.args) is P
assert get_origin(P.kwargs) is P

Added in version 3.8.

typing.get_args(tp)

Get type arguments with all substitutions performed: for a typing object of the form X[Y, Z, ...] return (Y, Z, ...).

If X is a union or Literal contained in another generic type, the order of (Y, Z, ...) may be different from the order of the original arguments [Y, Z, ...] due to type caching. Return () for unsupported objects.

Examples:

assert get_args(int) == ()
assert get_args(Dict[int, str]) == (int, str)
assert get_args(Union[int, str]) == (int, str)

Added in version 3.8.

typing.get_protocol_members(tp)

Return the set of members defined in a Protocol.

>>> from typing import Protocol, get_protocol_members
>>> class P(Protocol):
...     def a(self) -> str: ...
...     b: int
>>> get_protocol_members(P) == frozenset({'a', 'b'})
True

Raise TypeError for arguments that are not Protocols.

Added in version 3.13.

typing.is_protocol(tp)

Determine if a type is a Protocol.

예를 들면:

class P(Protocol):
    def a(self) -> str: ...
    b: int

is_protocol(P)    # => True
is_protocol(int)  # => False

Added in version 3.13.

typing.is_typeddict(tp)

Check if a type is a TypedDict.

For example:

class Film(TypedDict):
    title: str
    year: int

assert is_typeddict(Film)
assert not is_typeddict(list | str)

# TypedDict is a factory for creating typed dicts,
# not a typed dict itself
assert not is_typeddict(TypedDict)

Added in version 3.10.

class typing.ForwardRef

Class used for internal typing representation of string forward references.

For example, List["SomeClass"] is implicitly transformed into List[ForwardRef("SomeClass")]. ForwardRef should not be instantiated by a user, but may be used by introspection tools.

참고

PEP 585 [https://peps.python.org/pep-0585/] generic types such as list["SomeClass"] will not be implicitly transformed into list[ForwardRef("SomeClass")] and thus will not automatically resolve to list[SomeClass].

Added in version 3.7.4.

버전 3.14에서 변경: This is now an alias for annotationlib.ForwardRef.

typing.evaluate_forward_ref(forward_ref, *, owner=None, globals=None, locals=None, type_params=None, format=annotationlib.Format.VALUE)

Evaluate an annotationlib.ForwardRef as a type hint.

This is similar to calling annotationlib.ForwardRef.evaluate(), but unlike that method, evaluate_forward_ref() also:

Recursively evaluates forward references nested within the type hint.

Raises TypeError when it encounters certain objects that are not valid type hints.

Replaces type hints that evaluate to None with types.NoneType.

Supports the FORWARDREF and STRING formats.

forward_ref must be an instance of ForwardRef. owner, if given, should be the object that holds the annotations that the forward reference derived from, such as a module, class object, or function. It is used to infer the namespaces to use for looking up names. globals and locals can also be explicitly given to provide the global and local namespaces. type_params is a tuple of type parameters that are in scope when evaluating the forward reference. This parameter must be provided (though it may be an empty tuple) if owner is not given and the forward reference does not already have an owner set. format specifies the format of the annotation and is a member of the annotationlib.Format enum.

Added in version 3.14.

typing.NoDefault

A sentinel object used to indicate that a type parameter has no default value. For example:

>>> T = TypeVar("T")
>>> T.__default__ is typing.NoDefault
True
>>> S = TypeVar("S", default=None)
>>> S.__default__ is None
True

Added in version 3.13.

상수

typing.TYPE_CHECKING

A special constant that is assumed to be True by 3rd party static type checkers. It is False at runtime.

용법:

if TYPE_CHECKING:
    import expensive_mod

def fun(arg: 'expensive_mod.SomeType') -> None:
    local_var: expensive_mod.AnotherType = other_fun()

첫 번째 어노테이션은 따옴표로 묶여야 합니다, “전방 참조”로 만들어서 인터프리터 실행 시간에 expensive_mod 참조를 숨깁니다. 지역 변수에 대한 형 어노테이션은 평가되지 않기 때문에, 두 번째 어노테이션을 따옴표로 묶을 필요는 없습니다.

참고

If from __future__ import annotations is used, annotations are not evaluated at function definition time. Instead, they are stored as strings in __annotations__. This makes it unnecessary to use quotes around the annotation (see PEP 563 [https://peps.python.org/pep-0563/]).

Added in version 3.5.2.

Deprecated aliases

This module defines several deprecated aliases to pre-existing standard library classes. These were originally included in the typing module in order to support parameterizing these generic classes using []. However, the aliases became redundant in Python 3.9 when the corresponding pre-existing classes were enhanced to support [] (see PEP 585 [https://peps.python.org/pep-0585/]).

The redundant types are deprecated as of Python 3.9. However, while the aliases may be removed at some point, removal of these aliases is not currently planned. As such, no deprecation warnings are currently issued by the interpreter for these aliases.

If at some point it is decided to remove these deprecated aliases, a deprecation warning will be issued by the interpreter for at least two releases prior to removal. The aliases are guaranteed to remain in the typing module without deprecation warnings until at least Python 3.14.

Type checkers are encouraged to flag uses of the deprecated types if the program they are checking targets a minimum Python version of 3.9 or newer.

Aliases to built-in types

class typing.Dict(dict, MutableMapping[KT, VT])

Deprecated alias to dict.

Note that to annotate arguments, it is preferred to use an abstract collection type such as Mapping rather than to use dict or typing.Dict.

버전 3.9부터 폐지됨: builtins.dict now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.List(list, MutableSequence[T])

Deprecated alias to list.

Note that to annotate arguments, it is preferred to use an abstract collection type such as Sequence or Iterable rather than to use list or typing.List.

버전 3.9부터 폐지됨: builtins.list now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Set(set, MutableSet[T])

Deprecated alias to builtins.set.

Note that to annotate arguments, it is preferred to use an abstract collection type such as collections.abc.Set rather than to use set or typing.Set.

버전 3.9부터 폐지됨: builtins.set now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.FrozenSet(frozenset, AbstractSet[T_co])

Deprecated alias to builtins.frozenset.

버전 3.9부터 폐지됨: builtins.frozenset now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

typing.Tuple

Deprecated alias for tuple.

tuple and Tuple are special-cased in the type system; see Annotating tuples for more details.

버전 3.9부터 폐지됨: builtins.tuple now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Type(Generic[CT_co])

Deprecated alias to type.

See The type of class objects for details on using type or typing.Type in type annotations.

Added in version 3.5.2.

버전 3.9부터 폐지됨: builtins.type now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

Aliases to types in collections

class typing.DefaultDict(collections.defaultdict, MutableMapping[KT, VT])

Deprecated alias to collections.defaultdict.

Added in version 3.5.2.

버전 3.9부터 폐지됨: collections.defaultdict now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.OrderedDict(collections.OrderedDict, MutableMapping[KT, VT])

Deprecated alias to collections.OrderedDict.

Added in version 3.7.2.

버전 3.9부터 폐지됨: collections.OrderedDict now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.ChainMap(collections.ChainMap, MutableMapping[KT, VT])

Deprecated alias to collections.ChainMap.

Added in version 3.6.1.

버전 3.9부터 폐지됨: collections.ChainMap now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Counter(collections.Counter, Dict[T, int])

Deprecated alias to collections.Counter.

Added in version 3.6.1.

버전 3.9부터 폐지됨: collections.Counter now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Deque(deque, MutableSequence[T])

Deprecated alias to collections.deque.

Added in version 3.6.1.

버전 3.9부터 폐지됨: collections.deque now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

Aliases to other concrete types

class typing.Pattern

class typing.Match

Deprecated aliases corresponding to the return types from re.compile() and re.match().

These types (and the corresponding functions) are generic over AnyStr. Pattern can be specialised as Pattern[str] or Pattern[bytes]; Match can be specialised as Match[str] or Match[bytes].

버전 3.9부터 폐지됨: re의 클래스 Pattern과 Match는 이제 []를 지원합니다. PEP 585 [https://peps.python.org/pep-0585/]와 제네릭 에일리어스 형을 참조하십시오.

class typing.Text

Deprecated alias for str.

Text is provided to supply a forward compatible path for Python 2 code: in Python 2, Text is an alias for unicode.

Text를 사용하여 값이 파이썬 2와 파이썬 3 모두와 호환되는 방식으로 유니코드 문자열을 포함해야 함을 나타내십시오:

def add_unicode_checkmark(text: Text) -> Text:
    return text + u' \u2713'

Added in version 3.5.2.

버전 3.11부터 폐지됨: Python 2 is no longer supported, and most type checkers also no longer support type checking Python 2 code. Removal of the alias is not currently planned, but users are encouraged to use str instead of Text.

Aliases to container ABCs in collections.abc

class typing.AbstractSet(Collection[T_co])

Deprecated alias to collections.abc.Set.

버전 3.9부터 폐지됨: collections.abc.Set now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Collection(Sized, Iterable[T_co], Container[T_co])

Deprecated alias to collections.abc.Collection.

Added in version 3.6.

버전 3.9부터 폐지됨: collections.abc.Collection now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Container(Generic[T_co])

Deprecated alias to collections.abc.Container.

버전 3.9부터 폐지됨: collections.abc.Container now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.ItemsView(MappingView, AbstractSet[tuple[KT_co, VT_co]])

Deprecated alias to collections.abc.ItemsView.

버전 3.9부터 폐지됨: collections.abc.ItemsView now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.KeysView(MappingView, AbstractSet[KT_co])

Deprecated alias to collections.abc.KeysView.

버전 3.9부터 폐지됨: collections.abc.KeysView now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Mapping(Collection[KT], Generic[KT, VT_co])

Deprecated alias to collections.abc.Mapping.

버전 3.9부터 폐지됨: collections.abc.Mapping now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.MappingView(Sized)

Deprecated alias to collections.abc.MappingView.

버전 3.9부터 폐지됨: collections.abc.MappingView now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.MutableMapping(Mapping[KT, VT])

Deprecated alias to collections.abc.MutableMapping.

버전 3.9부터 폐지됨: collections.abc.MutableMapping now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.MutableSequence(Sequence[T])

Deprecated alias to collections.abc.MutableSequence.

버전 3.9부터 폐지됨: collections.abc.MutableSequence now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.MutableSet(AbstractSet[T])

Deprecated alias to collections.abc.MutableSet.

버전 3.9부터 폐지됨: collections.abc.MutableSet now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Sequence(Reversible[T_co], Collection[T_co])

Deprecated alias to collections.abc.Sequence.

버전 3.9부터 폐지됨: collections.abc.Sequence now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.ValuesView(MappingView, Collection[_VT_co])

Deprecated alias to collections.abc.ValuesView.

버전 3.9부터 폐지됨: collections.abc.ValuesView now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

Aliases to asynchronous ABCs in collections.abc

class typing.Coroutine(Awaitable[ReturnType], Generic[YieldType, SendType, ReturnType])

Deprecated alias to collections.abc.Coroutine.

See Annotating generators and coroutines for details on using collections.abc.Coroutine and typing.Coroutine in type annotations.

Added in version 3.5.3.

버전 3.9부터 폐지됨: collections.abc.Coroutine now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.AsyncGenerator(AsyncIterator[YieldType], Generic[YieldType, SendType])

Deprecated alias to collections.abc.AsyncGenerator.

See Annotating generators and coroutines for details on using collections.abc.AsyncGenerator and typing.AsyncGenerator in type annotations.

Added in version 3.6.1.

버전 3.9부터 폐지됨: collections.abc.AsyncGenerator now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

버전 3.13에서 변경: The SendType parameter now has a default.

class typing.AsyncIterable(Generic[T_co])

Deprecated alias to collections.abc.AsyncIterable.

Added in version 3.5.2.

버전 3.9부터 폐지됨: collections.abc.AsyncIterable now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.AsyncIterator(AsyncIterable[T_co])

Deprecated alias to collections.abc.AsyncIterator.

Added in version 3.5.2.

버전 3.9부터 폐지됨: collections.abc.AsyncIterator now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Awaitable(Generic[T_co])

Deprecated alias to collections.abc.Awaitable.

Added in version 3.5.2.

버전 3.9부터 폐지됨: collections.abc.Awaitable now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

Aliases to other ABCs in collections.abc

class typing.Iterable(Generic[T_co])

Deprecated alias to collections.abc.Iterable.

버전 3.9부터 폐지됨: collections.abc.Iterable now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Iterator(Iterable[T_co])

Deprecated alias to collections.abc.Iterator.

버전 3.9부터 폐지됨: collections.abc.Iterator now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

typing.Callable

Deprecated alias to collections.abc.Callable.

See Annotating callable objects for details on how to use collections.abc.Callable and typing.Callable in type annotations.

버전 3.9부터 폐지됨: collections.abc.Callable now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

버전 3.10에서 변경: Callable now supports ParamSpec and Concatenate. See PEP 612 [https://peps.python.org/pep-0612/] for more details.

class typing.Generator(Iterator[YieldType], Generic[YieldType, SendType, ReturnType])

Deprecated alias to collections.abc.Generator.

See Annotating generators and coroutines for details on using collections.abc.Generator and typing.Generator in type annotations.

버전 3.9부터 폐지됨: collections.abc.Generator now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

버전 3.13에서 변경: Default values for the send and return types were added.

class typing.Hashable

Deprecated alias to collections.abc.Hashable.

버전 3.12부터 폐지됨: Use collections.abc.Hashable directly instead.

class typing.Reversible(Iterable[T_co])

Deprecated alias to collections.abc.Reversible.

버전 3.9부터 폐지됨: collections.abc.Reversible now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

class typing.Sized

Deprecated alias to collections.abc.Sized.

버전 3.12부터 폐지됨: Use collections.abc.Sized directly instead.

Aliases to contextlib ABCs

class typing.ContextManager(Generic[T_co, ExitT_co])

Deprecated alias to contextlib.AbstractContextManager.

The first type parameter, T_co, represents the type returned by the __enter__() method. The optional second type parameter, ExitT_co, which defaults to bool | None, represents the type returned by the __exit__() method.

Added in version 3.5.4.

버전 3.9부터 폐지됨: contextlib.AbstractContextManager now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

버전 3.13에서 변경: Added the optional second type parameter, ExitT_co.

class typing.AsyncContextManager(Generic[T_co, AExitT_co])

Deprecated alias to contextlib.AbstractAsyncContextManager.

The first type parameter, T_co, represents the type returned by the __aenter__() method. The optional second type parameter, AExitT_co, which defaults to bool | None, represents the type returned by the __aexit__() method.

Added in version 3.6.2.

버전 3.9부터 폐지됨: contextlib.AbstractAsyncContextManager now supports subscripting ([]). See PEP 585 [https://peps.python.org/pep-0585/] and 제네릭 에일리어스 형.

버전 3.13에서 변경: Added the optional second type parameter, AExitT_co.

Deprecation Timeline of Major Features

Certain features in typing are deprecated and may be removed in a future version of Python. The following table summarizes major deprecations for your convenience. This is subject to change, and not all deprecations are listed.

Feature

Deprecated in

Projected removal

PEP/issue

typing versions of standard collections

3.9

Undecided (see Deprecated aliases for more information)

PEP 585 [https://peps.python.org/pep-0585/]

typing.Text

3.11

Undecided

gh-92332 [https://github.com/python/cpython/issues/92332]

typing.Hashable and typing.Sized

3.12

Undecided

gh-94309 [https://github.com/python/cpython/issues/94309]

typing.TypeAlias

3.12

Undecided

PEP 695 [https://peps.python.org/pep-0695/]

@typing.no_type_check_decorator

3.13

3.15

gh-106309 [https://github.com/python/cpython/issues/106309]

typing.AnyStr

3.13

3.18

gh-105578 [https://github.com/python/cpython/issues/105578]

pydoc — Documentation generator and online help system

소스 코드: Lib/pydoc.py [https://github.com/python/cpython/tree/main/Lib/pydoc.py]

The pydoc module automatically generates documentation from Python modules. The documentation can be presented as pages of text on the console, served to a web browser, or saved to HTML files.

For modules, classes, functions and methods, the displayed documentation is derived from the docstring (i.e. the __doc__ attribute) of the object, and recursively of its documentable members. If there is no docstring, pydoc tries to obtain a description from the block of comment lines just above the definition of the class, function or method in the source file, or at the top of the module (see inspect.getcomments()).

The built-in function help() invokes the online help system in the interactive interpreter, which uses pydoc to generate its documentation as text on the console. The same text documentation can also be viewed from outside the Python interpreter by running pydoc as a script at the operating system’s command prompt. For example, running

python -m pydoc sys

를 셸 프롬프트에서 실행하면, sys 모듈의 설명서를 유닉스 man 명령으로 표시되는 매뉴얼 페이지와 비슷한 스타일로 표시합니다. pydoc의 인자는 함수, 모듈 또는 패키지의 이름이거나 모듈이나 패키지의 모듈 내의 클래스, 메서드 또는 함수에 대한 점으로 구분된 참조일 수 있습니다. pydoc에 대한 인자가 경로처럼 보이고 (즉, 유닉스의 슬래시와 같이 운영 체제의 경로 구분 기호가 포함되어 있으면), 기존 파이썬 소스 파일을 가리키면, 해당 파일에 대한 설명서가 생성됩니다.

참고

In order to find objects and their documentation, pydoc imports the module(s) to be documented. Therefore, any code on module level will be executed on that occasion. Use an if __name__ == '__main__': guard to only execute code when a file is invoked as a script and not just imported.

When printing output to the console, pydoc attempts to paginate the output for easier reading. If either the MANPAGER or the PAGER environment variable is set, pydoc will use its value as a pagination program. When both are set, MANPAGER is used.

인자 앞에 -w 플래그를 지정하면 콘솔에 텍스트를 표시하는 대신, HTML 설명서가 현재 디렉터리에 파일로 기록됩니다.

인자 앞에 -k 플래그를 지정하면 인자로 주어진 키워드에 대해 사용 가능한 모든 모듈의 개요 행을 검색할 수 있습니다. 역시 유닉스 man 명령과 유사한 방식입니다. 모듈의 개요 행은 설명서 문자열의 첫 행입니다.

You can also use pydoc to start an HTTP server on the local machine that will serve documentation to visiting web browsers. python -m pydoc -p 1234 will start a HTTP server on port 1234, allowing you to browse the documentation at http://localhost:1234/ in your preferred web browser. Specifying 0 as the port number will select an arbitrary unused port.

python -m pydoc -n <hostname> will start the server listening at the given hostname. By default the hostname is ‘localhost’ but if you want the server to be reached from other machines, you may want to change the host name that the server responds to. During development this is especially useful if you want to run pydoc from within a container.

python -m pydoc -b will start the server and additionally open a web browser to a module index page. Each served page has a navigation bar at the top where you can Get help on an individual item, Search all modules with a keyword in their synopsis line, and go to the Module index, Topics and Keywords pages.

pydoc이 설명서를 생성할 때, 현재 환경과 경로를 사용하여 모듈을 찾습니다. 따라서, pydoc spam을 호출하면 정확히 파이썬 인터프리터를 시작하고 import spam을 입력할 때 얻는 모듈의 버전을 설명합니다.

Module docs for core modules are assumed to reside in https://docs.python.org/X.Y/library/ where X and Y are the major and minor version numbers of the Python interpreter. This can be overridden by setting the PYTHONDOCS environment variable to a different URL or to a local directory containing the Library Reference Manual pages.

버전 3.2에서 변경: -b 옵션이 추가되었습니다.

버전 3.3에서 변경: -g 명령 줄 옵션이 제거되었습니다.

버전 3.4에서 변경: pydoc now uses inspect.signature() rather than inspect.getfullargspec() to extract signature information from callables.

버전 3.7에서 변경: -n 옵션이 추가되었습니다.

파이썬 개발 모드

Added in version 3.7.

파이썬 개발 모드에는 기본적으로 활성화하기에 너무 비싼 추가 실행 시간 검사를 도입합니다. 코드가 올바르면 기본값보다 더 상세하지(verbose) 않아야 합니다; 새로운 경고는 문제가 감지될 때만 발생합니다.

-X dev 명령 줄 옵션을 사용하거나 PYTHONDEVMODE 환경 변수를 1로 설정하여 활성화할 수 있습니다.

See also Python debug build.

파이썬 개발 모드의 효과

파이썬 개발 모드를 활성화하는 것은 다음 명령과 유사하지만, 아래에 설명된 추가 효과가 있습니다:

PYTHONMALLOC=debug PYTHONASYNCIODEBUG=1 python -W default -X faulthandler

파이썬 개발 모드의 효과:

default 경고 필터를 추가합니다. 다음과 같은 경고가 표시됩니다:

DeprecationWarning

ImportWarning

PendingDeprecationWarning

ResourceWarning

일반적으로, 위의 경고는 기본 경고 필터가 필터링합니다.

-W default 명령 줄 옵션이 사용된 것처럼 작동합니다.

경고를 에러로 처리하려면 -W error 명령 줄 옵션을 사용하거나 PYTHONWARNINGS 환경 변수를 error로 설정하십시오.

메모리 할당자에 디버그 훅을 설치하여 다음을 확인합니다:

버퍼 언더플로

버퍼 오버플로

메모리 할당자 API 위반

GIL의 안전하지 않은 사용

PyMem_SetupDebugHooks() C 함수를 참조하십시오.

PYTHONMALLOC 환경 변수가 debug로 설정된 것처럼 동작합니다.

메모리 할당자에 디버그 훅을 설치하지 않고 파이썬 개발 모드를 사용하려면, PYTHONMALLOC 환경 변수를 default로 설정하십시오.

Call faulthandler.enable() at Python startup to install handlers for the SIGSEGV, SIGFPE, SIGABRT, SIGBUS and SIGILL signals to dump the Python traceback on a crash.

-X faulthandler 명령 줄 옵션이 사용되거나 PYTHONFAULTHANDLER 환경 변수가 1로 설정된 것처럼 작동합니다.

asyncio 디버그 모드를 활성화합니다. 예를 들어, asyncio는 어웨이트 하지 않은 코루틴을 확인하고 이를 로그 합니다.

PYTHONASYNCIODEBUG 환경 변수가 1로 설정된 것처럼 동작합니다.

문자열 인코딩과 디코딩 연산에 대해 encoding과 errors 인자를 확인합니다. 예: open(), str.encode() 및 bytes.decode().

기본적으로, 최상의 성능을 위해, errors 인자는 첫 번째 인코딩/디코딩 에러에서만 검사되며 빈 문자열에 대해서는 encoding 인자가 무시되는 경우가 있습니다.

io.IOBase 파괴자는 close() 예외를 로그 합니다.

Set the dev_mode attribute of sys.flags to True.

파이썬 개발 모드는 (성능과 메모리에 대한) 오버헤드 비용이 너무 비싸서, 기본적으로 tracemalloc 모듈을 활성화하지 않습니다. tracemalloc 모듈을 활성화하면 일부 에러의 원인에 대한 추가 정보가 제공됩니다. 예를 들어, ResourceWarning은 자원이 할당된 곳의 트레이스백을 로그하고, 버퍼 오버플로 에러는 메모리 블록이 할당된 곳의 트레이스백을 로그 합니다.

파이썬 개발 모드는 -O 명령 줄 옵션이 assert 문을 제거하거나 __debug__를 False로 설정하는 것을 막지 않습니다.

The Python Development Mode can only be enabled at the Python startup. Its value can be read from sys.flags.dev_mode.

버전 3.8에서 변경: io.IOBase 파괴자는 이제 close() 예외를 로그 합니다.

버전 3.9에서 변경: encoding과 errors 인자는 이제 문자열 인코딩과 디코딩 연산을 검사합니다.

ResourceWarning 예

명령 줄에 지정된 텍스트 파일의 줄 수를 세는 스크립트의 예:

import sys

def main():
    fp = open(sys.argv[1])
    nlines = len(fp.readlines())
    print(nlines)
    # The file is closed implicitly

if __name__ == "__main__":
    main()

스크립트는 파일을 명시적으로 닫지 않습니다. 기본적으로, 파이썬은 아무런 경고도 하지 않습니다. 269 줄이 있는 README.txt를 사용하는 예:

$ python script.py README.txt
269

파이썬 개발 모드를 사용하면 ResourceWarning 경고가 표시됩니다:

$ python -X dev script.py README.txt
269
script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='README.rst' mode='r' encoding='UTF-8'>
  main()
ResourceWarning: Enable tracemalloc to get the object allocation traceback

또한, tracemalloc을 활성화하면 파일이 열린 줄이 표시됩니다:

$ python -X dev -X tracemalloc=5 script.py README.rst
269
script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='README.rst' mode='r' encoding='UTF-8'>
  main()
Object allocated at (most recent call last):
  File "script.py", lineno 10
    main()
  File "script.py", lineno 4
    fp = open(sys.argv[1])

수선은 파일을 명시적으로 닫는 것입니다. 컨텍스트 관리자를 사용하는 예:

def main():
    # Close the file explicitly when exiting the with block
    with open(sys.argv[1]) as fp:
        nlines = len(fp.readlines())
    print(nlines)

자원을 명시적으로 닫지 않으면 예상보다 오래 자원을 열어둘 수 있습니다; 파이썬을 종료할 때 심각한 문제가 발생할 수 있습니다. CPython에서도 나쁘지만, PyPy에서는 더 나쁩니다. 리소스를 명시적으로 닫으면 응용 프로그램을 더 결정적이고 안정적으로 만들 수 있습니다.

잘못된 파일 기술자 에러 예

자신의 첫 줄을 표시하는 스크립트:

import os

def main():
    fp = open(__file__)
    firstline = fp.readline()
    print(firstline.rstrip())
    os.close(fp.fileno())
    # The file is closed implicitly

main()

기본적으로, 파이썬은 아무런 경고도 하지 않습니다:

$ python script.py
import os

파이썬 개발 모드는 ResourceWarning을 표시하고 파일 객체를 파이널라이즈 할 때 “잘못된 파일 기술자(Bad file descriptor)” 에러를 로그 합니다:

$ python -X dev script.py
import os
script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='script.py' mode='r' encoding='UTF-8'>
  main()
ResourceWarning: Enable tracemalloc to get the object allocation traceback
Exception ignored in: <_io.TextIOWrapper name='script.py' mode='r' encoding='UTF-8'>
Traceback (most recent call last):
  File "script.py", line 10, in <module>
    main()
OSError: [Errno 9] Bad file descriptor

os.close(fp.fileno())는 파일 기술자를 닫습니다. 파일 객체 파이널라이저가 파일 기술자를 다시 닫으려고 하면, Bad file descriptor 에러로 실패합니다. 파일 기술자는 한 번만 닫아야 합니다. 최악의 시나리오에서는, 두 번 닫을 때 충돌이 발생할 수 있습니다 (예는 bpo-18748 [https://bugs.python.org/issue?@action=redirect&bpo=18748]을 참조하십시오).

수선은 os.close(fp.fileno()) 줄을 제거하거나, closefd=False로 파일을 여는 것입니다.

doctest — Test interactive Python examples

소스 코드: Lib/doctest.py [https://github.com/python/cpython/tree/main/Lib/doctest.py]

doctest 모듈은 대화형 파이썬 세션처럼 보이는 텍스트를 검색한 다음, 해당 세션을 실행하여 표시된 대로 정확하게 작동하는지 검증합니다. doctest를 사용하는 몇 가지 일반적인 방법이 있습니다:

모든 대화식 예제가 설명된 대로 작동하는지 확인하여 모듈의 독스트링이 최신인지 확인합니다.

테스트 파일이나 테스트 객체의 대화형 예제가 예상대로 작동하는지 확인하여 회귀 테스트를 수행합니다.

입/출력 예제를 그대로 보여줌으로써 패키지에 대한 자습서를 작성합니다. 예제나 설명문 중 어느 것이 강조되는지에 따라, “문학적 테스트(literate testing)”나 “실행 가능한 설명서(executable documentation)”의 느낌을 줍니다.

여기에 완전하지만 작은 예제 모듈이 있습니다:

"""
This is the "example" module.

The example module supplies one function, factorial().  For example,

>>> factorial(5)
120
"""

def factorial(n):
    """Return the factorial of n, an exact integer >= 0.

    >>> [factorial(n) for n in range(6)]
    [1, 1, 2, 6, 24, 120]
    >>> factorial(30)
    265252859812191058636308480000000
    >>> factorial(-1)
    Traceback (most recent call last):
        ...
    ValueError: n must be >= 0

    Factorials of floats are OK, but the float must be an exact integer:
    >>> factorial(30.1)
    Traceback (most recent call last):
        ...
    ValueError: n must be exact integer
    >>> factorial(30.0)
    265252859812191058636308480000000

    It must also not be ridiculously large:
    >>> factorial(1e100)
    Traceback (most recent call last):
        ...
    OverflowError: n too large
    """

    import math
    if not n >= 0:
        raise ValueError("n must be >= 0")
    if math.floor(n) != n:
        raise ValueError("n must be exact integer")
    if n+1 == n:  # catch a value like 1e300
        raise OverflowError("n too large")
    result = 1
    factor = 2
    while factor <= n:
        result *= factor
        factor += 1
    return result

if __name__ == "__main__":
    import doctest
    doctest.testmod()

example.py를 명령 줄에서 직접 실행하면, doctest가 마술을 부리기 시작합니다:

$ python example.py
$

출력이 없습니다! 이것이 정상이며, 모든 예제가 작동했다는 것을 뜻합니다. -v를 스크립트에 전달하면, doctest는 시도하고 있는 내용에 대한 자세한 로그를 출력하고 끝에 요약을 인쇄합니다.:

$ python example.py -v
Trying:
    factorial(5)
Expecting:
    120
ok
Trying:
    [factorial(n) for n in range(6)]
Expecting:
    [1, 1, 2, 6, 24, 120]
ok

결국, 다음과 같이 끝납니다:

Trying:
    factorial(1e100)
Expecting:
    Traceback (most recent call last):
        ...
    OverflowError: n too large
ok
2 items passed all tests:
   1 test in __main__
   6 tests in __main__.factorial
7 tests in 2 items.
7 passed.
Test passed.
$

That’s all you need to know to start making productive use of doctest! Jump in. The following sections provide full details. Note that there are many examples of doctests in the standard Python test suite and libraries. Especially useful examples can be found in the standard test file Lib/test/test_doctest/test_doctest.py.

간단한 사용법: 독스트링에 있는 예제 확인하기

The simplest way to start using doctest (but not necessarily the way you’ll continue to do it) is to end each module M with:

if __name__ == "__main__":
    import doctest
    doctest.testmod()

doctest then examines docstrings in module M.

모듈을 스크립트로 실행하면 독스트링의 예제가 실행되고 검증됩니다:

python M.py

예제가 실패하지 않는 한 아무것도 표시되지 않습니다, 실패하면 실패한 예제와 실패 원인이 stdout으로 출력되고, 마지막 출력 줄은 ***Test Failed*** N failures.입니다. 여기서 N은 실패한 예제의 수입니다.

대신 -v 스위치로 실행해 보십시오:

python M.py -v

그러면 시도한 모든 예제에 대한 자세한 보고서가 표준 출력으로 출력되고, 끝에 정돈된 요약이 붙습니다.

verbose=True를 testmod()에 전달하여 상세 모드를 강제하거나, verbose=False를 전달하여 상세 모드를 금지할 수 있습니다. 두 경우 모두, sys.argv는 testmod()에 의해 검사되지 않습니다 (따라서 -v를 전달하거나 그렇지 않아도 효과가 없습니다).

또한 testmod()를 실행하는 명령 줄 단축법이 있습니다. 파이썬 인터프리터에게 표준 라이브러리에서 직접 doctest 모듈을 실행하도록 지시하고 명령 줄에 모듈 이름(들)을 전달할 수 있습니다:

python -m doctest -v example.py

이렇게 하면 example.py를 독립 실행형 모듈로 임포트하고, testmod()를 실행합니다. 파일이 패키지 일부이고 그 패키지에서 다른 서브 모듈을 임포트하면, 올바르게 작동하지 않을 수 있음에 유의하십시오.

testmod()에 대한 자세한 내용은, 기본 API 절을 참조하십시오.

간단한 사용법: 텍스트 파일에 있는 예제 확인하기

doctest의 또 다른 간단한 활용은 텍스트 파일에 있는 대화형 예제를 테스트하는 것입니다. 이것은 testfile() 함수로 수행할 수 있습니다:

import doctest
doctest.testfile("example.txt")

이 짧은 스크립트는 example.txt 파일에 들어있는 대화형 파이썬 예제를 실행하고 검증합니다. 파일 내용은 하나의 거대한 독스트링인 것처럼 취급됩니다; 파일이 파이썬 프로그램일 필요가 없습니다! 예를 들어, example.txt에 다음과 같은 것이 들어있습니다:

The ``example`` module
======================

Using ``factorial``
-------------------

This is an example text file in reStructuredText format.  First import
``factorial`` from the ``example`` module:

    >>> from example import factorial

Now use it:

    >>> factorial(6)
    120

doctest.testfile("example.txt")를 실행하면 이 문서에 있는 에러를 찾습니다:

File "./example.txt", line 14, in example.txt
Failed example:
    factorial(6)
Expected:
    120
Got:
    720

testmod()와 마찬가지로, testfile()은 예제가 실패하지 않는 한 아무것도 표시하지 않습니다. 예제가 실패하면, 실패한 예제와 실패 원인이 testmod()와 같은 형식을 사용하여 stdout에 인쇄됩니다.

기본적으로, testfile()은 호출하는 모듈의 디렉터리에서 파일을 찾습니다. 다른 위치에서 파일을 찾도록 지시하는 데 사용할 수 있는 선택적 인자에 대한 설명은 기본 API 절을 참조하십시오.

testmod()와 마찬가지로, testfile()의 상세도는 -v 명령 줄 스위치나 선택적 키워드 인자 verbose를 사용하여 설정할 수 있습니다.

또한 testfile()를 실행하는 명령 줄 단축법이 있습니다. 파이썬 인터프리터에게 표준 라이브러리에서 직접 doctest 모듈을 실행하도록 지시하고 명령 줄에 파일 이름(들)을 전달할 수 있습니다:

python -m doctest -v example.txt

파일 이름은 .py로 끝나지 않으므로, doctest는 testmod()가 아니라 testfile()로 실행되어야 한다고 추론합니다.

testfile()에 대한 자세한 내용은, 기본 API 절을 참조하십시오.

작동 방법

이 절에서는 doctest가 어떻게 작동하는지 자세히 설명합니다: 어떤 독스트링을 살피는지, 대화형 예제를 어떻게 찾는지, 사용하는 실행 컨텍스트는 무엇인지, 예외를 어떻게 처리하는지, 어떻게 옵션 플래그를 사용하여 동작을 제어하는지. 이것은 doctest 예제를 작성하기 위해 알아야 할 정보입니다; 이러한 예제에 대해 실제로 doctest를 실행하는 방법에 대한 자세한 내용은 다음 절을 참조하십시오.

어떤 독스트링을 검사합니까?

모듈 독스트링과 모든 함수, 클래스 및 메서드 독스트링이 검색됩니다. 모듈로 임포트 된 객체는 검색되지 않습니다.

In addition, there are cases when you want tests to be part of a module but not part of the help text, which requires that the tests not be included in the docstring. Doctest looks for a module-level variable called __test__ and uses it to locate other tests. If M.__test__ exists, it must be a dict, and each entry maps a (string) name to a function object, class object, or string. Function and class object docstrings found from M.__test__ are searched, and strings are treated as if they were docstrings. In output, a key K in M.__test__ appears with name M.__test__.K.

For example, place this block of code at the top of example.py:

__test__ = {
    'numbers': """
>>> factorial(6)
720

>>> [factorial(n) for n in range(6)]
[1, 1, 2, 6, 24, 120]
"""
}

The value of example.__test__["numbers"] will be treated as a docstring and all the tests inside it will be run. It is important to note that the value can be mapped to a function, class object, or module; if so, doctest searches them recursively for docstrings, which are then scanned for tests.

발견된 모든 클래스는 포함된 메서드와 중첩된 클래스의 독스트링을 테스트하기 위해 유사하게 재귀적으로 검색됩니다.

독스트링 예제는 어떻게 인식됩니까?

대부분 대화형 콘솔 세션의 복사하여 붙여넣기가 잘 작동하지만, doctest는 특정 파이썬 셸의 정확한 에뮬레이션을 시도하지 않습니다.

>>> # comments are ignored
>>> x = 12
>>> x
12
>>> if x == 13:
...     print("yes")
... else:
...     print("no")
...     print("NO")
...     print("NO!!!")
...
no
NO
NO!!!
>>>

모든 예상 출력은 코드가 포함된 마지막 '>>> ' 또는 '... ' 줄 바로 다음에 나와야 하며, (있다면) 예상 출력은 다음 '>>> ' 나 전체 공백 줄까지 확장됩니다.

세부 사항:

예상 출력은 전체 공백 줄을 포함할 수 없습니다. 그러한 줄은 예상 출력의 끝으로 인식되기 때문입니다. 예상 출력이 빈 줄을 포함하면, doctest 예제에서 빈 줄이 나타나는 곳에 <BLANKLINE>을 넣으십시오.

모든 하드 탭 문자는 8열 탭 정지를 사용하여 스페이스로 확장됩니다. 테스트 된 코드에 의해 생성된 출력의 탭은 수정되지 않습니다. 샘플 출력의 모든 하드 탭이 확장되므로, 이것은 코드 출력에 하드 탭이 포함될 때 doctest가 통과할 수 있는 유일한 방법은, NORMALIZE_WHITESPACE 옵션이나 지시자가 유효한 경우뿐임을 의미합니다. 또는, 출력을 캡처하여 테스트 일부로 예상값과 비교하도록 테스트를 다시 작성할 수 있습니다. 이러한 소스의 탭 처리는 시행착오를 거쳐 얻어진 것이며, 가장 에러가 발생하지 않는 방법으로 입증되었습니다. 사용자 정의 DocTestParser 클래스를 작성하여 탭 처리에 다른 알고리즘을 사용하는 것도 가능합니다.

stdout으로의 출력은 캡처되지만, stderr로의 출력은 그렇지 않습니다 (예외 트레이스백은 다른 수단을 통해 캡처됩니다).

대화식 세션에서 역 슬래시를 통해 줄을 계속하거나, 다른 이유로 백 슬래시를 사용하면, 날 독스트링(raw docstring)을 사용해서 역 슬래시를 입력한 그대로 유지해야 합니다:

>>> def f(x):
...     r'''Backslashes in a raw docstring: m\n'''
...
>>> print(f.__doc__)
Backslashes in a raw docstring: m\n

그렇지 않으면, 백 슬래시가 문자열 일부로 해석됩니다. 예를 들어, 위의 \n은 개행 문자로 해석됩니다. 또는, doctest 버전에서 각 백 슬래시를 중복시킬 수 있습니다 (그리고 날 문자열은 사용하지 않습니다):

>>> def f(x):
...     '''Backslashes in a raw docstring: m\\n'''
...
>>> print(f.__doc__)
Backslashes in a raw docstring: m\n

시작 열은 중요하지 않습니다:

>>> assert "Easy!"
      >>> import math
          >>> math.floor(1.9)
          1

그리고 예제를 시작한 초기 '>>> ' 줄에 나타나는 것만큼의 선행 공백을 예상 출력에서 제거합니다.

실행 컨텍스트란 무엇입니까?

By default, each time doctest finds a docstring to test, it uses a shallow copy of M’s globals, so that running tests doesn’t change the module’s real globals, and so that one test in M can’t leave behind crumbs that accidentally allow another test to work. This means examples can freely use any names defined at top-level in M, and names defined earlier in the docstring being run. Examples cannot see names defined in other docstrings.

대신 globs=your_dict를 testmod()나 testfile()로 전달하여 실행 컨텍스트로 여러분 자신의 딕셔너리를 사용하도록 할 수 있습니다.

예외는 어떻게 됩니까?

문제없습니다, 트레이스백이 예제에 의해 생성된 유일한 출력이기만 하면 됩니다: 그냥 트레이스백을 붙여넣으십시오. [1] 트레이스백에는 빠르게 변할 가능성이 있는 세부 사항(예를 들어, 정확한 파일 경로와 줄 번호)이 포함되어 있으므로, 이것은 doctest가 수락할 내용에 유연하도록 신경 써야 하는 한 가지 사례입니다.

간단한 예:

>>> [1, 2, 3].remove(42)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: list.remove(x): x not in list

이 doctest는 list.remove(x): x not in list 세부 정보를 포함하는 ValueError가 발생하면 성공합니다.

예외의 예상 출력은 다음 두 줄 중 한 가지가 예제의 첫 번째 줄과 같게 들여쓰기 된 트레이스백 헤더로 시작해야 합니다:

Traceback (most recent call last):
Traceback (innermost last):

트레이스백 헤더 다음에는 선택적인 트레이스백 스택이 오며, 그 내용은 doctest가 무시합니다. 보통 트레이스백 스택은 생략되거나, 대화형 세션에서 그대로 복사됩니다.

트레이스백 스택 다음에는 가장 흥미로운 부분이 옵니다: 예외 형과 세부 사항이 있는 줄. 대개 이것은 트레이스백의 마지막 줄이지만, 예외에 여러 줄로 구성된 세부 사항이 있으면 여러 줄로 확장될 수 있습니다:

>>> raise ValueError('multi\n    line\ndetail')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: multi
    line
detail

(ValueError로 시작하는) 마지막 세 줄이 예외의 형 및 세부 사항과 비교되고, 나머지는 무시됩니다.

모범 사례는 예제에 중요한 설명으로서의 가치를 추가하지 않는 한 트레이스백 스택을 생략하는 것입니다. 따라서 마지막 예제는 이렇게 하는 것이 더 좋습니다:

>>> raise ValueError('multi\n    line\ndetail')
Traceback (most recent call last):
    ...
ValueError: multi
    line
detail

트레이스백이 매우 특별하게 취급된다는 점에 유의하십시오. 특히, 다시 작성된 예제에서, ...의 사용은 doctest의 ELLIPSIS 옵션과 무관합니다. 이 예제의 줄임표는 생략하거나, 3개(혹은 300개)의 쉼표나 숫자 또는 몬티 파이썬 쇼의 들여쓰기 된 대본이어도 똑같이 잘 동작합니다.

한 번쯤 읽어야 할 세부 정보이지만, 기억할 필요는 없습니다:

Doctest는 예상 출력이 예외 트레이스백에서 온 것인지 일반 인쇄에서 온 것인지 추측할 수 없습니다. 그래서, 예를 들어, ValueError: 42 is prime을 예상하는 예제는 ValueError가 실제로 발생해도 통과하지만, 예제가 단지 그 트레이스백 텍스트를 출력해도 통과합니다. 실제로는, 일반 출력은 거의 트레이스백 헤더 줄로 시작하지 않으므로, 실제 문제가 되지는 않습니다.

(있다면) 트레이스백 스택의 각 줄은 예제의 첫 번째 줄보다 더 들여쓰기 되거나, 또는 영숫자(alphanumeric)가 아닌 문자로 시작해야 합니다. 트레이스백 헤더 뒤에 같은 정도로 들여쓰기 되고, 영숫자로 시작하는 첫 번째 줄은 예외 세부 사항의 시작으로 간주합니다. 물론 이것은 진짜 트레이스백에 잘 들어맞습니다.

IGNORE_EXCEPTION_DETAIL doctest 옵션을 지정하면, 가장 왼쪽 콜론 다음에 오는 모든 것과 예외 이름의 모듈 정보가 무시됩니다.

대화형 셸은 일부 SyntaxError에서 트레이스백 헤더 줄을 생략합니다. 그러나 doctest는 트레이스백 헤더 줄을 사용하여 예외를 비 예외와 구별합니다. 따라서 트레이스백 헤더를 생략하는 SyntaxError를 테스트해야 하는 드문 경우에는, 트레이스백 헤더 줄을 수동으로 테스트 예제에 추가해야 합니다.

For some exceptions, Python displays the position of the error using ^ markers and tildes:

>>> 1 + None
  File "<stdin>", line 1
    1 + None
    ~~^~~~~~
TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

에러의 위치를 나타내는 줄은 예외 형과 세부 사항 앞에 오므로, doctest가 점검하지 않습니다. 예를 들어, ^ 마커를 잘못된 위치에 넣어도, 다음 테스트가 통과합니다:

>>> 1 + None
  File "<stdin>", line 1
    1 + None
    ^~~~~~~~
TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

옵션 플래그

많은 옵션 플래그가 doctest의 다양한 동작을 제어합니다. 플래그의 기호 이름은 모듈 상수로 제공되며, 함께 비트별 OR되어 다양한 함수로 전달될 수 있습니다. 이 이름은 doctest 지시자에서도 사용될 수 있으며, -o 옵션을 통해 doctest 명령 줄 인터페이스로 전달될 수 있습니다.

Added in version 3.4: -o 명령 줄 옵션.

첫 번째 옵션 그룹은 테스트의 의미를 정의하는데, doctest가 실제 출력이 예제의 예상 출력과 일치하는지를 결정하는 측면을 제어합니다:

doctest.DONT_ACCEPT_TRUE_FOR_1

기본적으로, 예상 출력 블록에 1 만 있으면, 단지 1이나 True 만 포함된 실제 출력 블록을 일치하는 것으로 간주하며, 0과 False도 유사하게 다룹니다. DONT_ACCEPT_TRUE_FOR_1이 지정되면, 두 치환 모두 허용되지 않습니다. 기본 동작은 파이썬이 많은 함수의 반환형을 정수에서 논릿값으로 변경했다는 것을 반영합니다; “작은 정수” 출력을 예상하는 doctest가 이러한 경우에 여전히 작동합니다. 아마도 이 옵션은 사라지게 되겠지만, 몇 년 동안은 남아있을 겁니다.

doctest.DONT_ACCEPT_BLANKLINE

기본적으로, 예상 출력 블록에 <BLANKLINE> 문자열만 포함된 줄이 있으면, 해당하는 줄은 실제 출력의 빈 줄과 일치합니다. 진짜 빈 줄은 예상 출력을 끝내므로, 이것이 빈 줄을 예상하는 유일한 방법입니다. DONT_ACCEPT_BLANKLINE이 지정되면, 이 치환은 허용되지 않습니다.

doctest.NORMALIZE_WHITESPACE

지정되면, 모든 공백(빈칸과 개행) 시퀀스는 같게 취급됩니다. 예상 출력 내의 모든 공백 시퀀스는 실제 출력 내의 모든 공백 시퀀스와 일치합니다. 기본적으로, 공백은 정확히 일치해야 합니다. NORMALIZE_WHITESPACE는 예상 출력 줄이 매우 길고 소스의 여러 줄에 걸쳐 줄넘김하려는 경우에 특히 유용합니다.

doctest.ELLIPSIS

지정되면, 예상 출력의 줄임표(...)가 실제 출력의 모든 부분 문자열과 일치 할 수 있습니다. 여기에는 줄 경계를 넘는 부분 문자열과 빈 부분 문자열이 포함되므로, 사용을 간단하게 유지하는 것이 가장 좋습니다. 복잡한 사용은 정규식에서 .*를 쓸 때처럼 “이런, 너무 많이 일치하는군!” 과 같은 상황을 만들 수 있습니다.

doctest.IGNORE_EXCEPTION_DETAIL

When specified, doctests expecting exceptions pass so long as an exception of the expected type is raised, even if the details (message and fully qualified exception name) don’t match.

For example, an example expecting ValueError: 42 will pass if the actual exception raised is ValueError: 3*14, but will fail if, say, a TypeError is raised instead. It will also ignore any fully qualified name included before the exception class, which can vary between implementations and versions of Python and the code/libraries in use. Hence, all three of these variations will work with the flag specified:

>>> raise Exception('message')
Traceback (most recent call last):
Exception: message

>>> raise Exception('message')
Traceback (most recent call last):
builtins.Exception: message

>>> raise Exception('message')
Traceback (most recent call last):
__main__.Exception: message

Note that ELLIPSIS can also be used to ignore the details of the exception message, but such a test may still fail based on whether the module name is present or matches exactly.

버전 3.2에서 변경: IGNORE_EXCEPTION_DETAIL은 이제 테스트 중인 예외를 포함하는 모듈과 관련된 정보도 무시합니다.

doctest.SKIP

지정되면, 예제를 전혀 실행하지 않습니다. 이것은 doctest 예제가 설명서와 테스트 케이스의 두 가지 역할을 하는 문맥에서, 설명을 위해 예제를 포함해야 하지만 검사하지는 않아야 할 때 유용할 수 있습니다. 예를 들어, 예제의 출력이 임의적일 수 있습니다; 또는 예제가 테스트 구동기에서 사용할 수 없는 자원에 의존할 수 있습니다.

SKIP 플래그는 임시로 “주석 처리한” 예제를 위해 사용될 수도 있습니다.

doctest.COMPARISON_FLAGS

위의 모든 비교 플래그를 함께 OR 한 비트 마스크.

두 번째 옵션 그룹은 테스트 실패가 보고되는 방식을 제어합니다:

doctest.REPORT_UDIFF

지정되면, 여러 줄의 예상 및 실제 출력을 수반하는 실패가 통합(unified) diff를 사용하여 표시됩니다.

doctest.REPORT_CDIFF

지정되면, 여러 줄의 예상 및 실제 출력을 수반하는 실패가 문맥(context) diff를 사용하여 표시됩니다.

doctest.REPORT_NDIFF

지정되면, 차이점은 널리 사용되는 ndiff.py 유틸리티와 같은 알고리즘을 사용하여, difflib.Differ로 계산됩니다. 이 방법은 줄 간의 차이뿐만 아니라 줄 안에서의 차이점을 표시하는 유일한 방법입니다. 예를 들어, 예상 출력 줄에 숫자 1이 포함된 줄에 실제 출력이 문자 l을 포함하고 있으면, 일치하지 않는 열 위치를 나타내는 캐럿(caret)이 들어간 줄이 삽입됩니다.

doctest.REPORT_ONLY_FIRST_FAILURE

지정되면, 각 doctest에서 실패한 첫 번째 예제를 표시하지만, 나머지 모든 예제에 대해서는 출력을 억제합니다. 이렇게 하면 doctest가 이전의 실패로 인해 망가진 올바른 예제를 보고하지 않게 되지만, 첫 번째 실패와 무관하게 실패한 잘못된 예제를 숨길 수도 있습니다. REPORT_ONLY_FIRST_FAILURE가 지정될 때, 나머지 예제는 여전히 실행되며, 보고된 총실패 수에 포함됩니다; 출력만 억제됩니다.

doctest.FAIL_FAST

지정되면, 첫 번째 실패 예제 후에 종료하고, 나머지 예제를 실행하지 않습니다. 따라서, 보고되는 실패 횟수는 최대 1입니다. 이 플래그는 디버깅 중에 유용할 수 있습니다, 첫 번째 실패 이후의 예제는 디버깅 출력조차 생성하지 않기 때문입니다.

doctest 명령 줄은 옵션 -f를 -o FAIL_FAST의 축약으로 받아들입니다.

Added in version 3.4.

doctest.REPORTING_FLAGS

위의 모든 보고(reporting) 플래그를 함께 OR 한 비트 마스크.

새로운 옵션 플래그 이름을 등록하는 방법도 있습니다만, 서브 클래스를 통해 doctest 내부를 확장하려고 하지 않는 한 유용하지는 않습니다:

doctest.register_optionflag(name)

지정된 이름으로 새로운 옵션 플래그를 만들고, 새로운 플래그의 정숫값을 반환합니다. register_optionflag()은 OutputChecker나 DocTestRunner를 서브 클래싱할 때 서브 클래스가 지원하는 새 옵션을 만들 때 사용할 수 있습니다. register_optionflag()는 항상 다음의 관용구를 사용하여 호출해야 합니다:

MY_FLAG = register_optionflag('MY_FLAG')

지시자

Doctest 지시자를 사용하면 개별 예제의 옵션 플래그를 수정할 수 있습니다. Doctest 지시자는 예제의 소스 코드 뒤에 오는 특수한 파이썬 주석입니다:

directive             ::=  "#" "doctest:" directive_options
directive_options     ::=  directive_option ("," directive_option)*
directive_option      ::=  on_or_off directive_option_name
on_or_off             ::=  "+" | "-"
directive_option_name ::=  "DONT_ACCEPT_BLANKLINE" | "NORMALIZE_WHITESPACE" | ...

+나 -와 지시자 옵션 이름 사이의 공백은 허용되지 않습니다. 지시자 옵션 이름은 위에 설명된 옵션 플래그 이름 중 하나일 수 있습니다.

예제의 doctest 지시자는 그 단일 예제에 대한 doctest의 동작을 수정합니다. 이름 붙인 동작을 활성화하려면 +를 사용하고, 비활성화하려면 -를 사용하십시오.

For example, this test passes:

>>> print(list(range(20)))  # doctest: +NORMALIZE_WHITESPACE
[0,   1,  2,  3,  4,  5,  6,  7,  8,  9,
10,  11, 12, 13, 14, 15, 16, 17, 18, 19]

Without the directive it would fail, both because the actual output doesn’t have two blanks before the single-digit list elements, and because the actual output is on a single line. This test also passes, and also requires a directive to do so:

>>> print(list(range(20)))  # doctest: +ELLIPSIS
[0, 1, ..., 18, 19]

Multiple directives can be used on a single physical line, separated by commas:

>>> print(list(range(20)))  # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
[0,    1, ...,   18,    19]

If multiple directive comments are used for a single example, then they are combined:

>>> print(list(range(20)))  # doctest: +ELLIPSIS
...                         # doctest: +NORMALIZE_WHITESPACE
[0,    1, ...,   18,    19]

As the previous example shows, you can add ... lines to your example containing only directives. This can be useful when an example is too long for a directive to comfortably fit on the same line:

>>> print(list(range(5)) + list(range(10, 20)) + list(range(30, 40)))
... # doctest: +ELLIPSIS
[0, ..., 4, 10, ..., 19, 30, ..., 39]

모든 옵션은 기본적으로 비활성화되고, 지시자가 표시된 예제에만 적용되므로, (지시자에 +를 통해) 옵션을 활성화하는 것이 일반적으로 유일한 의미 있는 선택입니다. 하지만, doctest를 실행하는 함수에 옵션 플래그를 전달하여 다른 기본값을 설정할 수도 있습니다. 이럴 때, 지시자에서 -를 통해 옵션을 비활성화하는 것이 유용할 수 있습니다.

경고

doctest는 예상 출력에서 정확한 일치를 요구하는 것에 심각합니다. 단일 문자가 일치하지 않아도 테스트가 실패합니다. 여러분이 출력에 있어서 파이썬이 정확히 무엇을 보장하고 무엇을 보장하지 않는지 배워감에 따라, 이것은 아마도 여러분을 몇 번 놀라게 할 것입니다. 예를 들어, 집합을 인쇄할 때, 파이썬은 원소가 특정 순서로 인쇄되는 것을 보장하지 않으므로, 다음과 같은 테스트는

>>> foo()
{"spam", "eggs"}

취약합니다! 한 가지 해결 방법은 다음과 같습니다

>>> foo() == {"spam", "eggs"}
True

대신에. 또 다른 방법은

>>> d = sorted(foo())
>>> d
['eggs', 'spam']

다른 것들도 있지만, 아마 아이디어를 얻었을 겁니다.

Another bad idea is to print things that embed an object address, like

>>> id(1.0)  # certain to fail some of the time
7948648
>>> class C: pass
>>> C()  # the default repr() for instances embeds an address
<C object at 0x00AC18F0>

The ELLIPSIS directive gives a nice approach for the last example:

>>> C()  # doctest: +ELLIPSIS
<C object at 0x...>

부동 소수점 숫자도 플랫폼에 따라 약간의 출력 변동이 있습니다. 파이썬이 float 포매팅을 플랫폼 C 라이브러리에 위임하고 있고, 이때 C 라이브러리의 품질이 크게 다르기 때문입니다.

>>> 1./7  # risky
0.14285714285714285
>>> print(1./7) # safer
0.142857142857
>>> print(round(1./7, 6)) # much safer
0.142857

I/2.**J 형식의 숫자는 모든 플랫폼에서 안전하며, 저는 종종 이런 형식의 숫자를 만들도록 doctest 예제를 꾸밉니다:

>>> 3./4  # utterly safe
0.75

간단한 분수는 또한 사람들이 이해하기가 더 쉬우므로, 더 좋은 설명서가 되도록 합니다.

기본 API

testmod()와 testfile() 함수는 대부분 기본 사용에 충분한 doctest에 대한 간단한 인터페이스를 제공합니다. 이 두 함수에 대한 덜 형식적인 소개는 섹션 간단한 사용법: 독스트링에 있는 예제 확인하기와 간단한 사용법: 텍스트 파일에 있는 예제 확인하기를 참조하십시오.

doctest.testfile(filename, module_relative=True, name=None, package=None, globs=None, verbose=None, report=True, optionflags=0, extraglobs=None, raise_on_error=False, parser=DocTestParser(), encoding=None)

filename를 제외한 모든 인자는 선택적이며 키워드 형식으로 지정해야 합니다.

filename 파일에 있는 예제를 테스트합니다. (failure_count, test_count)를 반환합니다.

선택적 인자 module_relative는 filename을 해석하는 방법을 지정합니다:

module_relative가 True(기본값)이면, filename는 OS 독립적 모듈 상대 경로를 지정합니다. 기본적으로, 이 경로는 호출하는 모듈의 디렉터리에 상대적입니다; 그러나 package 인자가 지정되면, 해당 패키지에 상대적입니다. OS 독립성을 보장하기 위해, filename은 / 문자를 사용하여 경로 세그먼트를 분리해야 하며, 절대 경로일 수 없습니다 (즉, /로 시작할 수 없습니다).

module_relative가 False이면, filename은 OS 특정 경로를 지정합니다. 경로는 절대나 상대일 수 있습니다; 상대 경로는 현재 작업 디렉터리를 기준으로 해석됩니다.

선택적 인자 name은 테스트의 이름을 제공합니다; 기본적으로, 또는 None이면, os.path.basename(filename)이 사용됩니다.

선택적 인자 package는 디렉터리가 모듈 상대 filename의 기본 디렉터리로 사용될 파이썬 패키지나 파이썬 패키지의 이름입니다. 패키지를 지정하지 않으면, 호출하는 모듈의 디렉터리가 모듈 상대 filename의 기본 디렉터리로 사용됩니다. module_relative가 False일 때 package를 지정하는 것은 에러입니다.

선택적 인자 globs는 예제를 실행할 때 전역으로 사용될 딕셔너리를 제공합니다. doctest를 위해 이 딕셔너리의 새 얕은 사본이 만들어지므로, 예제는 깨끗한 서판으로 시작합니다. 기본적으로, 또는 None이면, 새 빈 딕셔너리가 사용됩니다.

선택적 인자 extraglobs는 예제를 실행하는 데 사용되는 전역에 병합될 딕셔너리를 제공합니다. 이것은 dict.update()처럼 작동합니다: globs와 extraglobs에 공통 키가 있으면, extraglobs의 연관된 값이 병합된 딕셔너리에 나타납니다. 기본적으로, 또는 None이면, 추가 전역은 사용되지 않습니다. doctest의 매개 변수화를 허용하는 고급 기능입니다. 예를 들어, doctest는 클래스의 일반 이름을 사용하여 베이스 클래스용으로 작성할 수 있습니다, 그런 다음 일반 이름을 테스트할 서브 클래스에 매핑하는 extraglobs 딕셔너리를 전달하여 임의의 수의 서브 클래스를 테스트하는데 재사용할 수 있습니다.

선택적 인자 verbose가 참이면 많은 것들을 인쇄하고, 거짓이면 실패만 인쇄합니다; 기본적으로, 또는 None이면, '-v'가 sys.argv에 있을 때만 참입니다.

선택적 인자 report가 참이면 끝에 요약을 인쇄하고, 그렇지 않으면 끝에 아무것도 인쇄하지 않습니다. verbose 모드에서는 요약 정보가 상세히 표시되며, 그렇지 않으면 요약 정보는 매우 간단합니다 (사실, 모든 테스트가 통과되면 비어 있습니다).

선택적 인자 optionflags(기본값은 0)는 옵션 플래그의 비트별 OR를 취합니다. 옵션 플래그 절을 참조하십시오.

선택적 인자 raise_on_error의 기본값은 거짓입니다. 참이면, 예제에서 첫 번째 실패나 예기치 않은 예외가 발생할 때 예외가 발생합니다. 이것은 실패를 사후(post-mortem) 디버깅할 수 있도록 합니다. 기본 동작은 예제를 계속 실행하는 것입니다.

선택적 인자 parser는 파일에서 테스트를 추출하는 데 사용할 DocTestParser(또는 서브 클래스)를 지정합니다. 기본값은 일반 파서(즉, DocTestParser())입니다.

선택적 인자 encoding은 파일을 유니코드로 변환하는 데 사용할 인코딩을 지정합니다.

doctest.testmod(m=None, name=None, globs=None, verbose=None, report=True, optionflags=0, extraglobs=None, raise_on_error=False, exclude_empty=False)

모든 인자는 선택적이며, m을 제외한 모든 인자는 키워드 형식으로 지정해야 합니다.

모듈 m(또는 m가 제공되지 않았거나 None이면 모듈 __main__)에서 도달할 수 있는 함수와 클래스의 독스트링에 있는 예제를 테스트합니다. m.__doc__으로 시작합니다.

Also test examples reachable from dict m.__test__, if it exists. m.__test__ maps names (strings) to functions, classes and strings; function and class docstrings are searched for examples; strings are searched directly, as if they were docstrings.

모듈 m에 속하는 객체에 연결된 독스트링 만 검색합니다.

(failure_count, test_count)를 반환합니다.

선택적 인자 name은 모듈의 이름을 제공합니다; 기본적으로, 또는 None이면, m.__name__이 사용됩니다.

Optional argument exclude_empty defaults to false. If true, objects for which no doctests are found are excluded from consideration. The default is a backward compatibility hack, so that code still using doctest.master.summarize in conjunction with testmod() continues to get output for objects with no tests. The exclude_empty argument to the newer DocTestFinder constructor defaults to true.

선택적 인자 extraglobs, verbose, report, optionflags, raise_on_error 및 globs는 위의 함수 testfile()와 같습니다만, globs의 기본값이 m.__dict__인 점이 다릅니다.

doctest.run_docstring_examples(f, globs, verbose=False, name='NoName', compileflags=None, optionflags=0)

객체 f와 관련된 예제를 테스트합니다. 여기서, f는 문자열, 모듈, 함수 또는 클래스 객체일 수 있습니다.

딕셔너리 인자 globs의 얕은 사본이 실행 컨텍스트에 사용됩니다.

선택적 인자 name은 실패 메시지에서 사용되며, 기본값은 "NoName"입니다.

선택적 인자 verbose가 참이면, 실패가 없어도 출력이 생성됩니다. 기본적으로, 출력은 예제가 실패할 때만 생성됩니다.

선택적 인자 compileflags는 예제를 실행할 때 파이썬 컴파일러에서 사용해야 하는 플래그 집합을 제공합니다. 기본적으로, 또는 None이면, globs에서 발견되는 퓨처 기능 집합에 해당하는 플래그가 추론됩니다.

선택적 인자 optionflags는 위의 함수 testfile()에서 처럼 작동합니다.

Unittest API

As your collection of doctest’ed modules grows, you’ll want a way to run all their doctests systematically. doctest provides two functions that can be used to create unittest test suites from modules and text files containing doctests. To integrate with unittest test discovery, include a load_tests function in your test module:

import unittest
import doctest
import my_module_with_doctests

def load_tests(loader, tests, ignore):
    tests.addTests(doctest.DocTestSuite(my_module_with_doctests))
    return tests

Doctest가 있는 텍스트 파일과 모듈로부터 unittest.TestSuite 인스턴스를 만드는 두 가지 주요 함수가 있습니다:

doctest.DocFileSuite(*paths, module_relative=True, package=None, setUp=None, tearDown=None, globs=None, optionflags=0, parser=DocTestParser(), encoding=None)

하나 이상의 텍스트 파일로부터 doctest 테스트를 unittest.TestSuite로 변환합니다.

The returned unittest.TestSuite is to be run by the unittest framework and runs the interactive examples in each file. If an example in any file fails, then the synthesized unit test fails, and a failureException exception is raised showing the name of the file containing the test and a (sometimes approximate) line number. If all the examples in a file are skipped, then the synthesized unit test is also marked as skipped.

검사할 텍스트 파일을 하나 이상의 paths(문자열)로 전달합니다.

옵션은 키워드 인자로 제공될 수 있습니다:

선택적 인자 module_relative는 paths에 있는 파일명을 해석하는 방법을 지정합니다:

module_relative가 True(기본값)이면, paths의 각 파일명은 OS 독립적 모듈 상대 경로를 지정합니다. 기본적으로, 이 경로는 호출하는 모듈의 디렉터리에 상대적입니다; 그러나 package 인자가 지정되면, 해당 패키지에 상대적입니다. OS 독립성을 보장하기 위해, 각 파일명은 / 문자를 사용하여 경로 세그먼트를 분리해야 하며, 절대 경로일 수 없습니다 (즉, /로 시작할 수 없습니다).

module_relative가 False이면, paths의 각 파일명은 OS 특정 경로를 지정합니다. 경로는 절대나 상대일 수 있습니다; 상대 경로는 현재 작업 디렉터리를 기준으로 해석됩니다.

선택적 인자 package는 디렉터리가 paths의 모듈 상대 파일명의 기본 디렉터리로 사용될 파이썬 패키지나 파이썬 패키지의 이름입니다. 패키지를 지정하지 않으면, 호출하는 모듈의 디렉터리가 모듈 상대 파일명의 기본 디렉터리로 사용됩니다. module_relative가 False일 때 package를 지정하는 것은 에러입니다.

선택적 인자 setUp은 테스트 스위트에 대한 사전 설정(set-up) 함수를 지정합니다. 이것은 각 파일에서 테스트를 실행하기 전에 호출됩니다. setUp 함수로 DocTest 객체가 전달됩니다. setUp 함수는 전달된 테스트의 globs 어트리뷰트를 통해 테스트 전역에 액세스할 수 있습니다.

선택적 인자 tearDown은 테스트 스위트에 사후 정리(tear-down) 함수를 지정합니다. 이것은 각 파일에서 테스트를 실행한 후에 호출됩니다. tearDown 함수로 DocTest 객체가 전달됩니다. tearDown 함수는 전달된 테스트의 globs 어트리뷰트를 통해 테스트 전역에 액세스할 수 있습니다.

선택적 인자 globs는 테스트의 초기 전역 변수를 포함하는 딕셔너리입니다. 이 딕셔너리의 새 사본이 테스트마다 만들어집니다. 기본적으로, globs는 새로운 빈 딕셔너리입니다.

선택적 인자 optionflags는 테스트에 대한 기본 doctest 옵션을 지정하는데, 개별 옵션 플래그를 함께 OR 해서 만들어집니다. 옵션 플래그 절을 참조하십시오. 보고(reporting) 옵션을 설정하는 더 좋은 방법은 아래 함수 set_unittest_reportflags()를 참조하십시오.

선택적 인자 parser는 파일에서 테스트를 추출하는 데 사용할 DocTestParser(또는 서브 클래스)를 지정합니다. 기본값은 일반 파서(즉, DocTestParser())입니다.

선택적 인자 encoding은 파일을 유니코드로 변환하는 데 사용할 인코딩을 지정합니다.

전역 __file__이 DocFileSuite()를 사용하여 텍스트 파일에서 로드된 doctest에 제공된 전역에 추가됩니다.

doctest.DocTestSuite(module=None, globs=None, extraglobs=None, test_finder=None, setUp=None, tearDown=None, optionflags=0, checker=None)

모듈에 대한 doctest 테스트를 unittest.TestSuite로 변환합니다.

The returned unittest.TestSuite is to be run by the unittest framework and runs each doctest in the module. If any of the doctests fail, then the synthesized unit test fails, and a failureException exception is raised showing the name of the file containing the test and a (sometimes approximate) line number. If all the examples in a docstring are skipped, then the synthesized unit test is also marked as skipped.

선택적 인자 module은 테스트할 모듈을 제공합니다. 모듈 객체나 (점으로 구분될 수 있는) 모듈 이름일 수 있습니다. 지정하지 않으면, 이 함수를 호출하는 모듈이 사용됩니다.

선택적 인자 globs는 테스트의 초기 전역 변수를 포함하는 딕셔너리입니다. 이 딕셔너리의 새 사본이 테스트마다 만들어집니다. 기본적으로, globs는 새로운 빈 딕셔너리입니다.

선택적 인자 extraglobs는 globs에 병합되는 전역 변수의 추가 집합을 지정합니다. 기본적으로, 추가 전역 변수는 사용되지 않습니다.

선택적 인자 test_finder는 모듈에서 doctest를 추출하는 데 사용되는 DocTestFinder 객체(또는 드롭 인 대체)입니다.

선택적 인자 setUp, tearDown 및 optionflags는 위의 함수 DocFileSuite()와 같습니다.

이 함수는 testmod()와 같은 검색 기법을 사용합니다.

버전 3.5에서 변경: module에 독스트링이 없으면 DocTestSuite()는 ValueError를 발생시키는 대신 빈 unittest.TestSuite를 반환합니다.

exception doctest.failureException

When doctests which have been converted to unit tests by DocFileSuite() or DocTestSuite() fail, this exception is raised showing the name of the file containing the test and a (sometimes approximate) line number.

Under the covers, DocTestSuite() creates a unittest.TestSuite out of doctest.DocTestCase instances, and DocTestCase is a subclass of unittest.TestCase. DocTestCase isn’t documented here (it’s an internal detail), but studying its code can answer questions about the exact details of unittest integration.

Similarly, DocFileSuite() creates a unittest.TestSuite out of doctest.DocFileCase instances, and DocFileCase is a subclass of DocTestCase.

So both ways of creating a unittest.TestSuite run instances of DocTestCase. This is important for a subtle reason: when you run doctest functions yourself, you can control the doctest options in use directly, by passing option flags to doctest functions. However, if you’re writing a unittest framework, unittest ultimately controls when and how tests get run. The framework author typically wants to control doctest reporting options (perhaps, e.g., specified by command line options), but there’s no way to pass options through unittest to doctest test runners.

이러한 이유로, doctest는 unittest 지원에 특화된 doctest 보고(reporting) 플래그 개념을 다음 함수를 통해 지원합니다:

doctest.set_unittest_reportflags(flags)

사용할 doctest 보고 플래그를 설정합니다.

인자 flags는 옵션 플래그의 비트별 OR를 취합니다. 옵션 플래그 절을 참조하십시오. “보고 플래그”만 사용할 수 있습니다.

This is a module-global setting, and affects all future doctests run by module unittest: the runTest() method of DocTestCase looks at the option flags specified for the test case when the DocTestCase instance was constructed. If no reporting flags were specified (which is the typical and expected case), doctest’s unittest reporting flags are bitwise ORed into the option flags, and the option flags so augmented are passed to the DocTestRunner instance created to run the doctest. If any reporting flags were specified when the DocTestCase instance was constructed, doctest’s unittest reporting flags are ignored.

함수가 호출되기 전에 유효했던 unittest 보고 플래그의 값이 함수에 의해 반환됩니다.

고급 API

기본 API는 doctest를 사용하기 쉽게 하기 위한 간단한 래퍼입니다. 그것은 매우 유연하며, 대부분 사용자의 요구를 충족시켜야 합니다; 그러나, 테스팅에 대한 세밀한 제어가 필요하거나, doctest의 기능을 확장하려면, 고급 API를 사용해야 합니다.

고급 API는 doctest 케이스에서 추출한 대화식 예제를 저장하는 데 사용되는 두 개의 컨테이너 클래스를 중심으로 돌아갑니다:

Example: 예상 출력과 쌍을 이루는 단일 파이썬 문장.

DocTest: 일반적으로 단일 독스트링이나 텍스트 파일에서 추출된 Example의 모음.

doctest 예제를 찾고, 구문 분석하고, 실행하고, 검사하기 위해 추가 처리 클래스가 정의됩니다:

DocTestFinder: 주어진 모듈에서 모든 독스트링을 찾고, DocTestParser를 사용하여 대화식 예제가 들어있는 모든 독스트링에서 DocTest를 만듭니다.

DocTestParser: 문자열(가령 객체의 독스트링)에서 DocTest 객체를 만듭니다.

DocTestRunner: DocTest에 있는 예제를 실행하고, OutputChecker를 사용하여 출력을 확인합니다.

OutputChecker: doctest 예제의 실제 출력을 예상 출력과 비교하고, 그들이 일치하는지 결정합니다.

이러한 처리 클래스 간의 관계는 다음 도표에 요약되어 있습니다:

                            list of:
+------+                   +---------+
|module| --DocTestFinder-> | DocTest | --DocTestRunner-> results
+------+    |        ^     +---------+     |       ^    (printed)
            |        |     | Example |     |       |
            v        |     |   ...   |     v       |
           DocTestParser   | Example |   OutputChecker
                           +---------+

DocTest 객체

class doctest.DocTest(examples, globs, name, filename, lineno, docstring)

단일 이름 공간에서 실행되어야 하는 doctest 예제의 모음. 생성자 인자는 같은 이름의 어트리뷰트를 초기화하는 데 사용됩니다.

DocTest는 다음 어트리뷰트를 정의합니다. 이들은 생성자에 의해 초기화되며, 직접 수정하면 안 됩니다.

examples

이 테스트가 실행해야 하는 개별 대화형 파이썬 예제를 인코딩하는 Example 객체의 리스트.

globs

예제가 실행되어야 하는 이름 공간 (일명 전역). 이름을 값에 매핑하는 딕셔너리입니다. 예제가 만든 이름 공간의 모든 변경 사항(가령 새 변수 바인딩)은 테스트가 실행된 후 globs에 반영됩니다.

name

DocTest를 식별하는 문자열 이름. 일반적으로, 테스트가 추출된 객체나 파일의 이름입니다.

filename

이 DocTest가 추출된 파일의 이름; 또는 파일 이름을 알 수 없거나 파일에서 DocTest가 추출되지 않았으면 None.

lineno

이 DocTest가 시작되는 filename 내의 줄 번호, 또는 줄 번호가 없으면 None. 이 줄 번호는 파일의 시작 부분을 기준으로 0에서 시작합니다.

docstring

테스트가 추출된 문자열, 또는 문자열이 없거나 테스트가 문자열에서 추출되지 않았으면 None.

Example 객체

class doctest.Example(source, want, exc_msg=None, lineno=0, indent=0, options=None)

파이썬 문장과 예상 출력으로 구성된 단일 대화형 예제. 생성자 인자는 같은 이름의 어트리뷰트를 초기화하는 데 사용됩니다.

Example는 다음 어트리뷰트를 정의합니다. 이들은 생성자에 의해 초기화되며, 직접 수정하면 안 됩니다.

source

예제의 소스 코드가 포함된 문자열. 이 소스 코드는 단일 파이썬 문으로 구성되며 항상 개행으로 끝납니다; 생성자는 필요하면 개행 문자를 추가합니다.

want

예제의 소스 코드를 실행할 때 (stdout이나 예외 발생 시 트레이스백으로부터) 예상되는 출력. want는 출력이 예상되지 않으면 빈 문자열이고, 그렇지 않으면 개행으로 끝납니다. 생성자는 필요하면 개행을 추가합니다.

exc_msg

예제가 예외를 생성할 것으로 예상되면, 예제에서 생성된 예외 메시지; 또는 예외를 생성할 것으로 예상되지 않으면 None. 이 예외 메시지는 traceback.format_exception_only()의 반환 값과 비교됩니다. exc_msg는 None이 아니면 개행으로 끝납니다. 생성자는 필요하면 개행을 추가합니다.

lineno

이 예제가 시작하는 이 예제를 포함하는 문자열 내의 줄 번호. 이 줄 번호는 포함하는 문자열의 시작 부분을 기준으로 0에서 시작합니다.

indent

포함하는 문자열 내에서의 이 예제의 들여쓰기, 즉 예제의 첫 번째 프롬프트 앞에 오는 스페이스 문자의 수.

options

A dictionary mapping from option flags to True or False, which is used to override default options for this example. Any option flags not contained in this dictionary are left at their default value (as specified by the DocTestRunner’s optionflags). By default, no options are set.

DocTestFinder 객체

class doctest.DocTestFinder(verbose=False, parser=DocTestParser(), recurse=True, exclude_empty=True)

주어진 객체에 관련된 DocTest를 그것의 독스트링과 그것이 포함하는 객체의 독스트링으로부터 추출하기 위해서 사용되는 처리 클래스. DocTest는 모듈, 클래스, 함수, 메서드, 정적 메서드, 클래스 메서드 및 프로퍼티에서 추출할 수 있습니다.

선택적 인자 verbose는 파인더가 검색한 객체를 표시하는 데 사용될 수 있습니다. 기본값은 False (출력 없음)입니다.

선택적 인자 parser는 독스트링에서 doctest를 추출하는 데 사용되는 DocTestParser 객체 (또는 드롭 인 대체)를 지정합니다.

선택적 인자 recurse가 거짓이면, DocTestFinder.find()는 오직 주어진 객체만을 검사 할 뿐, 포함된 객체는 검사하지 않습니다.

선택적 인자 exclude_empty가 거짓이면, DocTestFinder.find()는 빈 독스트링을 가진 객체에 대한 테스트를 포함합니다.

DocTestFinder는 다음 메서드를 정의합니다:

find(obj[, name][, module][, globs][, extraglobs])

obj의 독스트링이나 포함된 객체의 독스트링으로 정의된 DocTest의 리스트를 반환합니다.

선택적 인자 name은 객체의 이름을 지정합니다. 이 이름은 반환된 DocTest의 이름을 구성하는 데 사용됩니다. name이 지정되지 않으면, obj.__name__이 사용됩니다.

선택적 매개 변수 module은 주어진 객체를 포함하는 모듈입니다. 모듈이 지정되지 않거나 None이면, 테스트 파인더는 자동으로 올바른 모듈을 판별하려고 시도합니다. 객체의 모듈은 다음과 같이 사용됩니다:

globs가 지정되지 않으면, 기본 이름 공간으로.

DocTestFinder가 다른 모듈에서 임포트 된 객체에서 DocTest를 추출하지 못하도록 하려고. (module이 아닌 다른 모듈을 가진 포함 된 객체는 무시됩니다.)

객체를 포함하는 파일의 이름을 찾으려고.

해당 파일 내에서 객체의 줄 번호를 찾는 데 도움이 됩니다.

module이 False면, 모듈을 찾으려고 시도하지 않습니다. 이것은 눈에 띄지 않는데, 대부분 doctest 자체를 테스트할 때 사용합니다: module이 False이거나, None이지만 자동으로 찾을 수 없으면, 모든 객체는 (존재하지 않는) 모듈에 속한 것으로 간주하므로, 포함된 모든 객체에서 (재귀적으로) doctest를 검색합니다.

각 DocTest에 대한 전역은 globs와 extraglobs(extraglobs의 바인딩이 globs의 바인딩에 우선합니다)를 결합하여 구성됩니다. 각 DocTest마다 전역 딕셔너리의 새 얕은 복사본이 만들어집니다. globs를 지정하지 않으면, 기본값은 모듈이 지정되었다면 모듈의 __dict__, 또는 그렇지 않으면 {}입니다. extraglobs가 지정되지 않으면, 기본값은 {}입니다.

DocTestParser 객체

class doctest.DocTestParser

문자열에서 대화형 예제를 추출하고, 이를 사용하여 DocTest 객체를 만드는 데 사용되는 처리 클래스.

DocTestParser는 다음 메서드를 정의합니다:

get_doctest(string, globs, name, filename, lineno)

주어진 문자열에서 모든 doctest 예제를 추출하고, 이를 DocTest 객체로 모읍니다.

globs, name, filename 및 lineno는 새 DocTest 객체의 어트리뷰트입니다. 자세한 내용은 DocTest 설명서를 참조하십시오.

get_examples(string, name='<string>')

주어진 문자열에서 모든 doctest 예제를 추출하고, 이를 Example 객체의 리스트로 반환합니다. 줄 번호는 0부터 시작합니다. 선택적 인자 name은, 이 문자열을 식별하는 이름이며, 에러 메시지에만 사용됩니다.

parse(string, name='<string>')

주어진 문자열을 예제와 중간에 있는 텍스트로 나누고, 이를 Example와 문자열이 번갈아 나오는 리스트로 반환합니다. Example의 줄 번호는 0부터 시작합니다. 선택적 인자 name은, 이 문자열을 식별하는 이름이며, 에러 메시지에만 사용됩니다.

TestResults objects

class doctest.TestResults(failed, attempted)

failed

Number of failed tests.

attempted

Number of attempted tests.

skipped

Number of skipped tests.

Added in version 3.13.

DocTestRunner 객체

class doctest.DocTestRunner(checker=None, verbose=None, optionflags=0)

DocTest에 있는 대화형 예제를 실행하고 검증하는 데 사용되는 처리 클래스.

예상 출력과 실제 출력 간의 비교는 OutputChecker에 의해 수행됩니다. 이 비교는 여러 옵션 플래그로 사용자 정의할 수 있습니다; 자세한 내용은 옵션 플래그 절을 참조하십시오. 옵션 플래그로 충분하지 않으면, OutputChecker의 서브 클래스를 생성자에 전달하여 비교를 사용자 정의할 수도 있습니다.

The test runner’s display output can be controlled in two ways. First, an output function can be passed to run(); this function will be called with strings that should be displayed. It defaults to sys.stdout.write. If capturing the output is not sufficient, then the display output can be also customized by subclassing DocTestRunner, and overriding the methods report_start(), report_success(), report_unexpected_exception(), and report_failure().

선택적 키워드 인자 checker는 예상 출력을 doctest 예제의 실제 출력과 비교하는 데 사용되는 OutputChecker 객체(또는 드롭 인 대체)를 지정합니다.

선택적 키워드 인자 verbose는 DocTestRunner의 상세도를 제어합니다. verbose가 True이면, 실행될 때 각 예제에 대한 정보가 인쇄됩니다. verbose가 False이면, 실패만 인쇄됩니다. verbose가 지정되지 않거나 None이면, 명령 줄 스위치 -v가 사용될 때만 상세 출력이 사용됩니다.

선택적 키워드 인자 optionflags는 테스트 실행기가 예상 출력을 실제 출력과 비교하는 방법과 실패를 표시하는 방법을 제어하는 데 사용할 수 있습니다. 자세한 내용은 옵션 플래그 절을 참조하십시오.

The test runner accumulates statistics. The aggregated number of attempted, failed and skipped examples is also available via the tries, failures and skips attributes. The run() and summarize() methods return a TestResults instance.

DocTestRunner defines the following methods:

report_start(out, test, example)

테스트 러너가 주어진 예제를 처리하려고 한다고 보고합니다. 이 메서드는 DocTestRunner의 서브 클래스가 출력을 사용자 정의할 수 있도록 제공됩니다; 직접 호출해서는 안 됩니다.

example은 처리될 예제입니다. test는 예제를 포함하는 테스트입니다. out은 DocTestRunner.run()에 전달된 출력 함수입니다.

report_success(out, test, example, got)

주어진 예제가 성공적으로 실행되었음을 보고합니다. 이 메서드는 DocTestRunner의 서브 클래스가 출력을 사용자 정의할 수 있도록 제공됩니다; 직접 호출해서는 안 됩니다.

example은 처리될 예제입니다. got은 예제의 실제 출력입니다. test는 example을 포함하는 테스트입니다. out은 DocTestRunner.run()에 전달된 출력 함수입니다.

report_failure(out, test, example, got)

주어진 예제가 실패했음을 보고합니다. 이 메서드는 DocTestRunner의 서브 클래스가 출력을 사용자 정의할 수 있도록 제공됩니다; 직접 호출해서는 안 됩니다.

example은 처리될 예제입니다. got은 예제의 실제 출력입니다. test는 example을 포함하는 테스트입니다. out은 DocTestRunner.run()에 전달된 출력 함수입니다.

report_unexpected_exception(out, test, example, exc_info)

주어진 예제가 예기치 않은 예외를 발생시켰다고 보고합니다. 이 메서드는 DocTestRunner의 서브 클래스가 출력을 사용자 정의할 수 있도록 제공됩니다; 직접 호출해서는 안 됩니다.

example은 처리될 예제입니다. exc_info는 예기치 않은 예외에 대한 정보를 포함하는 튜플입니다 (sys.exc_info()에 의해 반환되는 것). test는 example을 포함하는 테스트입니다. out은 DocTestRunner.run()에 전달된 출력 함수입니다.

run(test, compileflags=None, out=None, clear_globs=True)

Run the examples in test (a DocTest object), and display the results using the writer function out. Return a TestResults instance.

예제는 이름 공간 test.globs에서 실행됩니다. clear_globs가 참(기본값)이면, 가비지 수집을 돕기 위해 테스트가 실행된 후 이 이름 공간이 지워집니다. 테스트가 완료된 후에 이름 공간을 검사하려면 clear_globs=False를 사용하십시오.

compileflags는 예제를 실행할 때 파이썬 컴파일러에서 사용해야 하는 플래그 집합을 제공합니다. 지정되지 않으면, globs에 적용되는 퓨처-임포트 플래그 집합이 기본값이 됩니다.

The output of each example is checked using the DocTestRunner’s output checker, and the results are formatted by the DocTestRunner.report_*() methods.

summarize(verbose=None)

Print a summary of all the test cases that have been run by this DocTestRunner, and return a TestResults instance.

선택적 verbose 인자는 요약이 얼마나 상세할지를 제어합니다. 상세도가 지정되지 않으면, DocTestRunner의 상세도가 사용됩니다.

DocTestParser has the following attributes:

tries

Number of attempted examples.

failures

Number of failed examples.

skips

Number of skipped examples.

Added in version 3.13.

OutputChecker 객체

class doctest.OutputChecker

doctest 예제의 실제 출력이 예상 출력과 일치하는지를 확인하는 데 사용되는 클래스. OutputChecker는 두 가지 메서드를 정의합니다: check_output()은 주어진 출력 쌍을 비교하고 일치하면 True를 반환합니다; output_difference()는 두 출력 간의 차이를 설명하는 문자열을 반환합니다.

OutputChecker는 다음 메서드를 정의합니다:

check_output(want, got, optionflags)

예제의 실제 출력(got)이 예상 출력(want)과 일치할 때만 True를 반환합니다. 이 문자열은 같으면 항상 일치하는 것으로 간주합니다; 그러나 테스트 실행기가 사용하는 옵션 플래그에 따라 몇 가지 정확하지 않은 일치 유형도 가능합니다. 옵션 플래그에 대한 자세한 정보는 옵션 플래그 절을 참조하십시오.

output_difference(example, got, optionflags)

주어진 예제(example)에 대한 예상 출력과 실제 출력(got)의 차이를 설명하는 문자열을 반환합니다. optionflags는 want와 got을 비교하는 데 사용되는 옵션 플래그 집합입니다.

디버깅

Doctest는 doctest 예제를 디버깅하기 위한 몇 가지 메커니즘을 제공합니다:

몇몇 함수는 doctest를 파이썬 디버거 pdb에서 실행할 수 있는 실행 가능한 파이썬 프로그램으로 변환합니다.

DebugRunner 클래스는 첫 번째 실패한 예제에 대한 예외를 발생시키는 DocTestRunner의 서브 클래스이며 해당 예제에 대한 정보가 들어 있습니다. 이 정보는 예제에서 사후 디버깅을 수행하는 데 사용될 수 있습니다.

DocTestSuite()에 의해 생성된 unittest 케이스는 unittest.TestCase에 의해 정의된 debug() 메서드를 지원합니다.

doctest 예제에 pdb.set_trace()에 대한 호출을 추가 할 수 있습니다. 그러면 해당하는 줄이 실행될 때 파이썬 디버거로 들어갑니다. 그런 다음 변수의 현재 값을 검사하는 등의 일을 할 수 있습니다. 예를 들어, a.py가 다음과 같은 모듈 독스트링을 포함한다고 가정합시다:

"""
>>> def f(x):
...     g(x*2)
>>> def g(x):
...     print(x+3)
...     import pdb; pdb.set_trace()
>>> f(3)
9
"""

그러면 대화형 파이썬 세션은 이런 식이 됩니다:

>>> import a, doctest
>>> doctest.testmod(a)
--Return--
> <doctest a[1]>(3)g()->None
-> import pdb; pdb.set_trace()
(Pdb) list
  1     def g(x):
  2         print(x+3)
  3  ->     import pdb; pdb.set_trace()
[EOF]
(Pdb) p x
6
(Pdb) step
--Return--
> <doctest a[0]>(2)f()->None
-> g(x*2)
(Pdb) list
  1     def f(x):
  2  ->     g(x*2)
[EOF]
(Pdb) p x
3
(Pdb) step
--Return--
> <doctest a[2]>(1)?()->None
-> f(3)
(Pdb) cont
(0, 3)
>>>

Doctest를 파이썬 코드로 변환하고, 디버거에서 합성 코드를 실행할 수 있는 함수들:

doctest.script_from_examples(s)

예제가 있는 텍스트를 스크립트로 변환합니다.

인자 s는 doctest 예제를 포함하는 문자열입니다. 문자열은 파이썬 스크립트로 변환됩니다. 여기서 s의 doctest 예제는 일반 코드로 변환되고, 나머지는 파이썬 주석으로 변환됩니다. 생성된 스크립트는 문자열로 반환됩니다. 예를 들어,

import doctest
print(doctest.script_from_examples(r"""
    Set x and y to 1 and 2.
    >>> x, y = 1, 2

    Print their sum:
    >>> print(x+y)
    3
"""))

는 다음과 같이 출력합니다:

# Set x and y to 1 and 2.
x, y = 1, 2
#
# Print their sum:
print(x+y)
# Expected:
## 3

이 함수는 다른 함수(아래 참조)에서 내부적으로 사용되지만, 대화형 파이썬 세션을 파이썬 스크립트로 변환하려고 할 때도 유용합니다.

doctest.testsource(module, name)

객체에 대한 doctest를 스크립트로 변환합니다.

Argument module is a module object, or dotted name of a module, containing the object whose doctests are of interest. Argument name is the name (within the module) of the object with the doctests of interest. The result is a string, containing the object’s docstring converted to a Python script, as described for script_from_examples() above. For example, if module a.py contains a top-level function f(), then

import a, doctest
print(doctest.testsource(a, "a.f"))

prints a script version of function f()’s docstring, with doctests converted to code, and the rest placed in comments.

doctest.debug(module, name, pm=False)

객체의 doctest를 디버그합니다.

module과 name 인자는 위의 함수 testsource()와 같습니다. 명명된 객체의 독스트링에 대한 합성된 파이썬 스크립트가 임시 파일에 기록되고, 그 파일을 파이썬 디버거 pdb의 제어하에 실행합니다.

module.__dict__의 얕은 사본이 지역과 전역 실행 컨텍스트 모두에 사용됩니다.

선택적 인자 pm은 사후 디버깅이 사용되는지를 제어합니다. pm이 참값이면, 스크립트 파일은 직접 실행되고, 처리되지 않은 예외를 발생시켜 스크립트가 종료될 때만 디버거가 개입합니다. 그럴 때, 사후 디버깅이 pdb.post_mortem()를 통해 호출되어, 처리되지 않은 예외로부터 온 트레이스백 객체를 전달합니다. pm이 지정되지 않았거나 거짓이면, 스크립트는 적절한 exec() 호출을 pdb.run()에 전달하여 시작부터 디버거에서 실행됩니다.

doctest.debug_src(src, pm=False, globs=None)

문자열에 있는 doctest를 디버그합니다.

doctest 예제를 포함하는 문자열이 src 인자를 통해 직접 지정된다는 점을 제외하면, 위의 함수 debug()과 같습니다.

선택적 인자 pm은 위의 함수 debug()에서와 같은 의미를 가집니다.

선택적 인자 globs는 지역과 전역 실행 컨텍스트 모두에 사용할 딕셔너리를 제공합니다. 지정되지 않거나 None이면, 빈 딕셔너리가 사용됩니다. 지정되면, 딕셔너리의 얕은 사본이 사용됩니다.

DebugRunner 클래스와 이 클래스가 발생시킬 수 있는 특별한 예외는 주로 테스트 프레임워크 작성자가 관심을 가지며, 여기에서는 대략적으로만 다룰 예정입니다. 자세한 내용은 소스 코드, 특히 DebugRunner의 독스트링(doctest입니다!)을 참조하십시오:

class doctest.DebugRunner(checker=None, verbose=None, optionflags=0)

실패를 만나자마자 예외를 발생시키는 DocTestRunner의 서브 클래스. 예기치 않은 예외가 발생하면, 테스트, 예제 및 원래 예외가 포함된 UnexpectedException 예외가 발생합니다. 출력이 일치하지 않으면, 테스트, 예제 및 실제 출력을 포함하는 DocTestFailure 예외가 발생합니다.

생성자 매개 변수와 메서드에 대한 자세한 내용은 고급 API 절의 DocTestRunner 설명서를 참조하십시오.

DebugRunner 인스턴스가 발생시킬 수 있는 두 가지 예외가 있습니다:

exception doctest.DocTestFailure(test, example, got)

doctest 예제의 실제 출력이 예상 출력과 일치하지 않는다는 것을 알리기 위해 DocTestRunner가 발생시키는 예외. 생성자 인자는 같은 이름의 어트리뷰트를 초기화하는 데 사용됩니다.

DocTestFailure는 다음 어트리뷰트를 정의합니다:

DocTestFailure.test

예제가 실패했을 때 실행 중이던 DocTest 객체.

DocTestFailure.example

실패한 Example.

DocTestFailure.got

예제의 실제 출력.

exception doctest.UnexpectedException(test, example, exc_info)

doctest 예제가 예기치 않은 예외를 발생시켰음을 알리기 위해 DocTestRunner가 발생시키는 예외. 생성자 인자는 같은 이름의 어트리뷰트를 초기화하는 데 사용됩니다.

UnexpectedException는 다음 어트리뷰트를 정의합니다:

UnexpectedException.test

예제가 실패했을 때 실행 중이던 DocTest 객체.

UnexpectedException.example

실패한 Example.

UnexpectedException.exc_info

sys.exc_info()에 의해 반환되는 것과 같은, 예기치 않은 예외에 대한 정보가 포함된 튜플.

맺음말

소개에서 언급했듯이, doctest는 다음 세 가지 주요 용도로 성장했습니다:

독스트링에 있는 예제 검사.

회귀 테스트.

실행 가능한 문서/문학적(literate) 테스트.

이러한 용도들은 다른 요구 사항을 가지며, 이를 구별하는 것이 중요합니다. 특히, 모호한 테스트 케이스로 독스트링을 채우는 것은 나쁜 설명서를 만듭니다.

독스트링을 작성할 때, 독스트링 예제를 주의해서 선택하십시오. 여기에는 배울 필요가 있는 기술이 있습니다—처음에는 자연스럽지 않을 수도 있습니다. 예제는 설명서에 진짜 가치를 부여해야 합니다. 좋은 예제는 종종 많은 단어의 가치가 있습니다. 주의 깊게 작업 된다면, 예제는 사용자에게 매우 가치 있을 것이며, 몇 년이 지나고 변함에 따라 여러 번 수집하는 데 드는 시간을 갚을 것입니다. 제 doctest 예제 중 하나가 “해가 없는” 변경 후에 얼마나 자주 작동을 멈추는지 지금도 놀라울 뿐입니다.

Doctest는 회귀 테스트를 위한 훌륭한 도구도 제공합니다. 특히 설명 텍스트를 생략하지 않는다면 더욱더 그렇습니다. 설명과 예제를 번갈아 보여줌으로써, 실제로 무엇이 왜 테스트 되는지를 추적하기가 훨씬 쉬워집니다. 테스트가 실패할 때, 좋은 설명은 문제가 무엇인지, 어떻게 고쳐야 하는지를 쉽게 파악할 수 있게 해줍니다. 코드 기반 테스트에 광범위한 주석을 쓸 수는 있는 것은 사실이지만, 그렇게 하는 프로그래머는 거의 없습니다. 많은 사람이 doctest 접근법을 사용하는 것이 훨씬 더 명확한 테스트를 유도한다는 것을 발견했습니다. 어쩌면 단순히 doctest가 설명을 작성하는 것을 코드를 작성하는 것보다 조금 더 쉽게 만들고, 코드에 주석을 쓰는 것이 조금 더 어렵기 때문일 것입니다. 저는 단지 그것보다는 더 깊이 들어간다고 생각합니다: doctest 기반 테스트를 작성할 때의 자연스러운 태도는 소프트웨어의 미세한 포인트를 설명하고 그것을 예제로 보여주는 것입니다. 이것은 자연스럽게 가장 간단한 기능으로 시작하고, 복잡하고 지엽적인 경우까지 논리적으로 진행되는 테스트 파일로 이어집니다. 무작위로 보이는 격리된 기능 조각을 테스트하는 격리된 함수들의 모음 대신에, 일관된 내러티브가 얻어집니다. 이것은 다른 태도이며, 테스트와 설명의 구별을 모호하게 하면서 다른 결과를 낳습니다.

회귀 테스트는 전용 객체나 파일로 제한하는 것이 가장 좋습니다. 테스트 구성을 위한 몇 가지 옵션이 있습니다.:

대화형 예제로 테스트 케이스가 들어있는 텍스트 파일을 작성하고, testfile()이나 DocFileSuite()를 사용하여 파일을 테스트하십시오. doctest를 처음부터 사용하도록 고안된 새로운 프로젝트에서 가장 쉬운 방법이지만, 이 방법을 권장합니다.

명명된 주제에 대한 테스트 케이스를 포함하는 단일 독스트링으로 구성된 _regrtest_topic이라는 함수를 정의하십시오. 이 함수들은 모듈과 같은 파일에 포함되거나 별도의 테스트 파일로 분리될 수 있습니다.

회귀 테스트 주제에서 테스트 케이스가 포함된 독스트링에 대한 __test__ 딕셔너리 매핑을 정의하십시오.

테스트를 모듈에 배치할 때, 모듈 자체가 테스트 실행기가 될 수 있습니다. 테스트가 실패할 때, 문제를 디버깅하는 동안 실패한 doctest 만 다시 실행하도록 테스트 실행기를 조정할 수 있습니다. 다음은 그러한 테스트 실행기의 최소 예입니다:

if __name__ == '__main__':
    import doctest
    flags = doctest.REPORT_NDIFF|doctest.FAIL_FAST
    if len(sys.argv) > 1:
        name = sys.argv[1]
        if name in globals():
            obj = globals()[name]
        else:
            obj = __test__[name]
        doctest.run_docstring_examples(obj, globals(), name=name,
                                       optionflags=flags)
    else:
        fail, total = doctest.testmod(optionflags=flags)
        print(f"{fail} failures out of {total} tests")

각주

[1]

예상 출력과 예외를 모두 포함하는 예제는 지원되지 않습니다. 어디에서 하나가 끝나고 다른 하나가 시작되는지 추측하는 것은 너무 에러가 발생하기 쉽고, 이것은 또한 혼란스러운 테스트를 만들게 됩니다.

unittest — Unit testing framework

소스 코드: Lib/unittest/__init__.py [https://github.com/python/cpython/tree/main/Lib/unittest/__init__.py]

(당신이 이미 테스트 기본 개념에 친숙하다면, assert 메서드 목록으로 건너뛰어도 좋습니다.)

unittest 단위 테스트 프레임워크는 본래 JUnit으로부터 영감을 받고 다른 언어의 주요 단위 테스트 프레임워크와 비슷한 특징을 가지고 있습니다. 이것은 테스트 자동화, 테스트를 위한 사전 설정(setup)과 종료(shutdown) 코드 공유, 테스트를 컬렉션에 종합하기, 테스트와 리포트 프레임워크의 분리 등을 지원합니다.

이를 달성하기 위해 unittest는 객체 지향적인 방법으로 몇 가지 중요한 개념을 지원합니다.

테스트 픽스쳐

테스트 픽스쳐 (test fixture)는 1개 또는 그 이상의 테스트를 수행할 때 필요한 준비와 그와 관련된 정리 동작에 해당합니다. 예를 들어 이것은 임시 또는 프락시 데이터베이스, 디렉터리를 생성하거나 서버 프로세스를 시작하는 것 등을 포함합니다.

테스트 케이스

테스트 케이스(test case)는 테스트의 개별 단위입니다. 이것은 특정한 입력 모음에 대해서 특정한 결과를 확인합니다. unittest는 베이스 클래스인 TestCase를 지원합니다. 이 클래스는 새로운 테스트 케이스를 만드는 데 사용됩니다.

테스트 묶음

테스트 묶음(test suite)은 여러 테스트 케이스, 테스트 묶음, 또는 둘 다의 모임입니다. 이것은 서로 같이 실행되어야 할 테스트들을 종합하는 데 사용됩니다.

테스트 실행자

테스트 실행자(test runner)는 테스트 실행을 조율하고 테스트 결과를 사용자에게 제공하는 역할을 하는 컴포넌트입니다. 실행자는 테스트 실행 결과를 보여주기 위해 그래픽 인터페이스, 텍스트 인터페이스를 사용하거나 특별한 값을 반환할 수도 있습니다.

더 보기

doctest 모듈

매우 다른 특징을 가지고 있는 또 다른 테스트 지원 모듈

Simple Smalltalk Testing: With Patterns [https://web.archive.org/web/20150315073817/http://www.xprogramming.com/testfram.htm]

unittest에 영향을 준 Kent Beck의 패턴을 사용한 테스트 프레임워크 원본 논문

pytest [https://docs.pytest.org/]

테스트를 작성하기에 간편한 문법을 가지고 있는 제삼자의 단위 테스트 프레임워크. 예시, assert func(10) == 42.

파이썬 테스트 도구 분류 [https://wiki.python.org/moin/PythonTestingToolsTaxonomy]

함수형 테스트 프레임워크와 모의 객체 라이브러리를 포함한 광범위한 파이썬 테스트 도구 목록

Testing in Python 메일링 리스트 [http://lists.idyll.org/listinfo/testing-in-python]

파이썬에서 테스트하기와 테스트 도구에 대해 논의하는 특정-주제-그룹(special-interest-group)

The script Tools/unittestgui/unittestgui.py in the Python source distribution is a GUI tool for test discovery and execution. This is intended largely for ease of use for those new to unit testing. For production environments it is recommended that tests be driven by a continuous integration system such as Buildbot [https://buildbot.net/], Jenkins [https://www.jenkins.io/], GitHub Actions [https://github.com/features/actions], or AppVeyor [https://www.appveyor.com/].

기본 예시

unittest 모듈은 테스트를 구성하고 실행하는 데 풍부한 도구 모음을 제공하고 있습니다. 이 절에서는 대부분 사용자의 요구를 충족시키기 위해 일부 도구 모음만으로도 충분하다는 것을 보여줍니다.

문자열 관련된 3개의 메서드를 테스트하기 위한 짧은 스크립트가 여기에 있습니다:

import unittest

class TestStringMethods(unittest.TestCase):

    def test_upper(self):
        self.assertEqual('foo'.upper(), 'FOO')

    def test_isupper(self):
        self.assertTrue('FOO'.isupper())
        self.assertFalse('Foo'.isupper())

    def test_split(self):
        s = 'hello world'
        self.assertEqual(s.split(), ['hello', 'world'])
        # check that s.split fails when the separator is not a string
        with self.assertRaises(TypeError):
            s.split(2)

if __name__ == '__main__':
    unittest.main()

테스트 케이스는 unittest.TestCase를 서브 클래스 해서 생성하였습니다. 각각 3개의 테스트는 test 글자로 시작하는 이름을 가진 메서드로 정의했습니다. 이 명명 규칙은 테스트 실행자가 어떤 메서드가 테스트인지 알게 해줍니다.

각 테스트의 핵심은 기대되는 결과를 확인하기 위해 assertEqual()를 호출, 조건을 검증하기 위해 assertTrue() 또는 assertFalse()를 호출, 특정 예외가 발생했는지 검증하기 위해 assertRaises()를 호출하는 것입니다. assert 문장을 대신하여 이 메서드들을 사용하면 테스트 실행자가 모든 테스트 결과를 취합하여 리포트를 생성할 수 있습니다.

setUp()과 tearDown() 메서드로 각각의 테스트 메서드 전과 후에 실행될 명령어를 정의할 수 있습니다. 테스트 코드 구조 잡기에서 이것을 더 자세히 다루겠습니다.

마지막 블록은 테스트를 실행하는 간단한 방법을 보여줍니다. unittest.main()은 테스트 스크립트에 명령행 인터페이스를 제공합니다. 명령행에서 위 스크립트를 실행하면, 다음과 같은 출력이 나옵니다:

...
----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK

-v 옵션을 테스트 스크립트에 넘겨주게 되면 unittest.main()은 높은 상세도(verbosity)를 설정하여 그에 따른 출력이 나옵니다:

test_isupper (__main__.TestStringMethods.test_isupper) ... ok
test_split (__main__.TestStringMethods.test_split) ... ok
test_upper (__main__.TestStringMethods.test_upper) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.001s

OK

위의 예시는 unittest에서 가장 자주 사용되는 기능을 보여주며 이것은 많은 일상적인 테스트 요구 사항을 충족시키기에 충분합니다. 문서의 나머지 부분은 기초부터 시작해서 모든 기능을 살펴봅니다.

버전 3.11에서 변경: The behavior of returning a value from a test method (other than the default None value), is now deprecated.

명령행 인터페이스

unittest 모듈은 명령행을 사용하여 모듈, 클래스, 심지어 각 테스트 메서드의 테스트들을 실행할 수 있습니다:

python -m unittest test_module1 test_module2
python -m unittest test_module.TestClass
python -m unittest test_module.TestClass.test_method

모듈 이름이나 완전히 정규화된 클래스나 메서드 이름이 포함된 목록을 전달할 수 있습니다.

테스트 모듈은 파일 경로로도 지정할 수 있습니다:

python -m unittest tests/test_something.py

이것으로 테스트 모듈을 지정할 때 셸(shell)의 파일 이름 완성 기능을 사용할 수 있습니다. 지정된 파일은 반드시 모듈로 임포트 가능해야 합니다. 파일 경로는 ‘.py’ 가 빠지면서 모듈 이름으로 변경되고 경로 구분자도 ‘.’로 변경됩니다. 만약 당신이 임포트 가능하지 않은 테스트 파일을 모듈로 사용하고 싶으시다면 이 방법 대신에 그 파일을 직접 실행해야 합니다.

-v 옵션을 사용하여 더 자세한 정보(높은 상세도)로 테스트를 실행할 수 있습니다:

python -m unittest -v test_module

아무 인자 없이 실행하면 테스트 탐색(Discovery)이 실행됩니다:

python -m unittest

모든 명령행 옵션 목록을 보기:

python -m unittest -h

버전 3.2에서 변경: 이전 버전에서는 개별 테스트 메서드만 실행이 가능했고, 모듈과 클래스는 불가능했습니다.

명령행 옵션

unittest는 다음과 같은 명령행 옵션을 제공합니다:

-b, --buffer

테스트가 실행될 동안 표준 출력과 표준 에러 스트림이 버퍼링 됩니다. 통과한 테스트 중에 나온 출력은 버려집니다. 보통 테스트 실패나 에러에서 나온 출력은 표시되고 실패 메시지에 추가됩니다.

-c, --catch

테스트 실행 중에 Control-C를 누르면 현재 테스트가 끝날 때까지 기다린 다음 지금까지의 모든 결과를 보고합니다. Control-C를 다시 누르면 일반적인 KeyboardInterrupt 예외를 발생합니다.

이 기능과 관련된 함수는 시그널 처리하기를 참고하십시오.

-f, --failfast

첫 번째 에러나 실패가 발생하면 테스트 실행을 중단합니다.

-k

Only run test methods and classes that match the pattern or substring. This option may be used multiple times, in which case all test cases that match any of the given patterns are included.

와일드카드 문자(*)를 포함한 패턴은 fnmatch.fnmatchcase()를 사용하여 그에 일치하는 테스트 이름을 찾고; 그렇지 않은 경우 단순히 대소문자를 구별하는 부분 문자열 일치가 사용됩니다.

패턴을 테스트 로더가 임포트한 완전히 정규화된 테스트 메서드 이름과 대조합니다.

예를 들어 -k foo는 foo_tests.SomeTest.test_something, bar_tests.SomeTest.test_foo에 일치하지만, bar_tests.FooTest.test_something에는 일치하지 않습니다.

--locals

트레이스백(traceback)에서 지역 변수를 표시합니다.

--durations N

Show the N slowest test cases (N=0 for all).

Added in version 3.2: 명령행 옵션인 -b, -c, -f가 추가되었습니다.

Added in version 3.5: 명령행 옵션 --locals.

Added in version 3.7: 명령행 옵션 -k.

Added in version 3.12: The command-line option --durations.

명령행은 프로젝트의 모든 테스트 또는 일부분의 테스트 탐색을 위해서도 사용할 수 있습니다.

테스트 탐색(Discovery)

Added in version 3.2.

Unittest supports simple test discovery. In order to be compatible with test discovery, all of the test files must be modules or packages importable from the top-level directory of the project (this means that their filenames must be valid identifiers).

테스트 탐색은 TestLoader.discover()로 구현되어 있습니다, 그러나 명령행으로 사용할 수도 있습니다. 기본적인 명령행 사용법은 다음과 같습니다:

cd project_directory
python -m unittest discover

참고

단축형인 python -m unittest는 python -m unittest discover와 같습니다. 테스트 탐색에 인자를 전달하고 싶을 때는 discover 부속 명령어(sub-command)를 명시적으로 사용해야 합니다.

discover 부-명령어는 다음과 같은 옵션을 가지고 있습니다:

-v, --verbose

상세한 출력

-s, --start-directory directory

탐색을 시작할 디렉터리(기본값 .)

-p, --pattern pattern

테스트 파일을 검색할 패턴(기본값 test*.py)

-t, --top-level-directory directory

프로젝트의 최상위 디렉터리(기본값 시작 디렉터리)

-s, -p, -t 옵션은 이 순서대로 위치 인자로서 사용할 수 있습니다. 다음 2개의 명령행은 같습니다:

python -m unittest discover -s project_directory -p "*_test.py"
python -m unittest discover project_directory "*_test.py"

경로가 사용되는 곳에 패키지 이름을 전달하는 것도 가능합니다, 예를 들어 myproject.subpackage.test를 시작 디렉터리로 사용할 수 있습니다. 주어진 패키지 이름은 임포트되어 그것의 파일 시스템상의 위치를 시작 디렉터리로 사용하게 됩니다.

조심

테스트 탐색은 테스트를 임포트하여 로드합니다. 테스트 탐색이 당신이 지정한 시작 디렉터리로부터 모든 테스트 파일을 찾았다면 임포트하기 위해 그 파일 경로를 패키지 이름으로 바꿉니다. 예를 들어 foo/bar/baz.py는 foo.bar.baz로 임포트될 것입니다.

만약 당신이 전역적으로 설치된 패키지가 있고 테스트 탐색을 다른 패키지 복사본에 하려고 시도한다면 임포트가 잘못된 위치에서 발생할 수도 있습니다. 만약 이런 일이 발생한다면 테스트 탐색은 경고하고 종료될 것입니다.

만약 당신이 시작 디렉터리로 경로가 아닌 패키지 이름을 전달했다면 테스트 탐색은 임포트가 어느 경로로부터 되었든 간에 당신이 의도한 경로라고 간주하여 경고를 발생하지 않을 것입니다.

테스트 모듈과 패키지는 load_tests 프로토콜을 통하여 테스트 로드와 탐색을 사용자 정의할 수 있습니다.

버전 3.4에서 변경: Test discovery supports namespace packages.

버전 3.11에서 변경: Test discovery dropped the namespace packages support. It has been broken since Python 3.7. Start directory and its subdirectories containing tests must be regular package that have __init__.py file.

If the start directory is the dotted name of the package, the ancestor packages can be namespace packages.

버전 3.14에서 변경: Test discovery supports namespace package as start directory again. To avoid scanning directories unrelated to Python, tests are not searched in subdirectories that do not contain __init__.py.

테스트 코드 구조 잡기

단위 테스트의 기본 구성 블록은 테스트 케이스(test cases) — 정확성을 위해 설정되고 확인될 하나의 시나리오입니다. unittest에서 테스트 케이스는 unittest.TestCase 인스턴스에 해당합니다. 당신만의 테스트 케이스를 만들기 위해서는 TestCase의 서브 클래스를 작성하거나 FunctionTestCase를 사용해야 합니다.

TestCase 인스턴스의 테스트 코드는 완전히 독립적으로 되어 있어야 합니다, 그래야지 이것을 각각 단독으로 실행하거나 다른 여러 테스트 케이스와 함께 임의의 조합으로 실행할 수 있습니다.

가장 간단한 TestCase의 서브 클래스는 특정 테스트 코드를 수행하도록 단순히 테스트 메서드(즉 test로 이름이 시작하는 함수)를 구현하는 것입니다:

import unittest

class DefaultWidgetSizeTestCase(unittest.TestCase):
    def test_default_widget_size(self):
        widget = Widget('The widget')
        self.assertEqual(widget.size(), (50, 50))

Note that in order to test something, we use one of the assert* methods provided by the TestCase base class. If the test fails, an exception will be raised with an explanatory message, and unittest will identify the test case as a failure. Any other exceptions will be treated as errors.

테스트는 매우 많지만, 그것을 위한 사전 설정은 계속 반복될 수 있습니다. 다행히, setUp()이란 메서드를 작성하여 사전 설정 코드를 밖으로 분리해낼 수 있습니다. 테스트 프레임워크가 1개의 테스트마다 매번 자동으로 이것을 호출할 것입니다:

import unittest

class WidgetTestCase(unittest.TestCase):
    def setUp(self):
        self.widget = Widget('The widget')

    def test_default_widget_size(self):
        self.assertEqual(self.widget.size(), (50,50),
                         'incorrect default size')

    def test_widget_resize(self):
        self.widget.resize(100,150)
        self.assertEqual(self.widget.size(), (100,150),
                         'wrong size after resize')

참고

다양한 테스트가 실행될 순서는 테스트 메서드의 이름을 가지고 내장된 문자열 정렬 순서에 의하여 결정될 것입니다.

만약 setUp() 메서드가 테스트 실행 중에 예외를 발생시킨다면 프레임워크는 테스트에 오류가 있는 것으로 간주하여 테스트 메서드를 실행하지 않을 것입니다.

마찬가지로 테스트 메서드가 실행되고 나서 정리하기 위해 tearDown() 메서드를 제공합니다:

import unittest

class WidgetTestCase(unittest.TestCase):
    def setUp(self):
        self.widget = Widget('The widget')

    def tearDown(self):
        self.widget.dispose()

만약 setUp()이 성공했다면, 테스트가 성공했든 실패했든 상관없이 tearDown()이 실행될 것입니다.

이와 같은 테스트를 위한 실행 환경을 테스트 픽스쳐(test fixture)라고 부릅니다. 개별 테스트 메서드를 실행하기 위해 고유한 테스트 픽스쳐에 해당하는 새로운 테스트 케이스 인스턴스가 생성됩니다. 따라서 setUp(), tearDown(), __init__()는 테스트 당 1번씩 실행됩니다.

테스트하려는 기능에 따라 테스트들을 같이 모아서 테스트 케이스 구현을 사용하는 것을 추천합니다. 이것을 위해 unittest는 메커니즘을 제공합니다: 테스트 묶음(test suite), 이것은 unittest의 TestSuite 클래스에 해당합니다. 대부분의 경우 unittest.main()이 테스트를 실행하기 위해 모듈의 모든 테스트 케이스를 수집하여 적절한 행동을 취할 것입니다.

그러나 당신이 테스트 묶음을 사용자 정의하고 싶다면 그것을 직접 만들어야 합니다:

def suite():
    suite = unittest.TestSuite()
    suite.addTest(WidgetTestCase('test_default_widget_size'))
    suite.addTest(WidgetTestCase('test_widget_resize'))
    return suite

if __name__ == '__main__':
    runner = unittest.TextTestRunner()
    runner.run(suite())

당신은 테스트 케이스와 테스트 묶음의 정의를 테스트하려는 코드와 같은 모듈(예를 들어 file:widget.py)에 넣을 수 있습니다, 그러나 테스트 코드를 분리된 모듈(예를 들어 test_widget.py)에 넣으면 몇 가지 이점이 있습니다:

테스트 모듈이 명령행에서 독립적으로 작동할 수 있습니다.

테스트 코드가 배포될 코드와 쉽게 분리될 수 있습니다.

충분한 이유 없이 테스트하려는 코드에 맞춰서 테스트 코드를 바꾸려는 유혹이 덜 합니다.

테스트 코드가 테스트하려는 코드에 비해 훨씬 덜 빈번하게 수정되어야 합니다.

테스트하려는 코드는 더 쉽게 리팩토링할 수 있습니다.

C 언어로 작성된 모듈의 테스트 코드는 반드시 분리된 모듈에 위치해야 합니다, 따라서 일관성을 지키는 것이 어떨까요?

만약 테스트 전략이 바뀌더라도 소스 코드를 바꿀 필요가 없습니다.

이전의 테스트 코드를 다시 사용하기

어떤 사용자들은 이전의 모든 테스트 함수를 TestCase 서브 클래스로 변경하는 작업 없이 기존의 테스트 코드를 unittest로 실행하고 싶어 할 것입니다.

이러한 이유로 unittest는 FunctionTestCase 클래스를 제공합니다. 이 TestCase의 서브 클래스는 기존 테스트 함수를 감싸는데 사용할 수 있습니다. 사전 설정과 정리 함수 또한 같이 사용할 수 있습니다.

다음과 같은 테스트 함수가 있을 때:

def testSomething():
    something = makeSomething()
    assert something.name is not None
    # ...

다음과 같이 동등한 테스트 케이스 인스턴스를 생성할 수 있습니다, 추가로 사전 설정과 정리 메서드를 함께 설정합니다:

testcase = unittest.FunctionTestCase(testSomething,
                                     setUp=makeSomethingDB,
                                     tearDown=deleteSomethingDB)

참고

FunctionTestCase를 사용하여 기존 테스트를 unittest-기반 시스템으로 빠르게 변경할 수 있을지라도 이 방법을 추천하지는 않습니다. 시간을 들여서 적절한 TestCase 서브 클래스를 설정하는 것이 미래에 있을 테스트 리팩토링을 대단히 쉽게 만들어줄 것입니다.

어떤 경우에는 doctest 모듈을 사용하여 기존 테스트가 작성되었을 수도 있습니다. 만약 그렇다면 doctest가 제공하는 DocTestSuite 클래스를 사용하여 기존의 doctest-기반 테스트로부터 unittest.TestSuite 인스턴스를 자동으로 만들 수 있습니다.

테스트 건너뛰기와 예상된 실패

Added in version 3.1.

unittest는 테스트 중에서 개별 테스트 메서드나 심지어 전체 클래스를 건너뛸 수 있는 기능을 제공합니다. 게다가 테스트를 “예상된 실패”로 표시하는 기능도 지원합니다, 테스트가 망가져서 실패하더라도 그것을 TestResult에 실패라고 기록하지 않습니다.

테스트 건너뛰기는 단순히 skip() 데코레이터나 그것의 조건 변형 중 하나를 사용하거나, setUp()이나 테스트 메서드 안에서 TestCase.skipTest()를 호출하거나, SkipTest를 직접 발생시키면 됩니다.

기본적인 건너뛰기는 다음과 같습니다:

class MyTestCase(unittest.TestCase):

    @unittest.skip("demonstrating skipping")
    def test_nothing(self):
        self.fail("shouldn't happen")

    @unittest.skipIf(mylib.__version__ < (1, 3),
                     "not supported in this library version")
    def test_format(self):
        # Tests that work for only a certain version of the library.
        pass

    @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
    def test_windows_support(self):
        # windows specific testing code
        pass

    def test_maybe_skipped(self):
        if not external_resource_available():
            self.skipTest("external resource not available")
        # test code that depends on the external resource
        pass

아래는 위의 예를 상세 모드로 실행했을 때의 출력입니다:

test_format (__main__.MyTestCase.test_format) ... skipped 'not supported in this library version'
test_nothing (__main__.MyTestCase.test_nothing) ... skipped 'demonstrating skipping'
test_maybe_skipped (__main__.MyTestCase.test_maybe_skipped) ... skipped 'external resource not available'
test_windows_support (__main__.MyTestCase.test_windows_support) ... skipped 'requires Windows'

----------------------------------------------------------------------
Ran 4 tests in 0.005s

OK (skipped=4)

클래스도 메서드처럼 건너뛰기가 가능합니다:

@unittest.skip("showing class skipping")
class MySkippedTestCase(unittest.TestCase):
    def test_not_run(self):
        pass

TestCase.setUp() 또한 테스트를 건너뛸 수 있습니다. 이것은 사전 설정해야 할 자원을 사용할 수 없을 때 유용합니다.

예상된 실패는 expectedFailure() 데코레이터를 사용합니다.

class ExpectedFailureTestCase(unittest.TestCase):
    @unittest.expectedFailure
    def test_fail(self):
        self.assertEqual(1, 0, "broken")

자신만의 건너뛰기 데코레이터를 만들기는 쉽습니다. 테스트를 건너뛰고 싶을 때 skip()를 호출하도록 데코레이터를 만들면 됩니다. 다음의 데코레이터는 특정 어트리뷰트가 있는 객체가 전달되지 않으면 테스트를 건너뜁니다:

def skipUnlessHasattr(obj, attr):
    if hasattr(obj, attr):
        return lambda func: func
    return unittest.skip("{!r} doesn't have {!r}".format(obj, attr))

다음 데코레이터들과 예외는 테스트 건너뛰기와 예상된 실패를 구현합니다:

@unittest.skip(reason)

조건 없이 데코레이트된 테스트를 건너뜁니다. reason은 왜 이 테스트가 건너뛰어 졌는지를 설명해야 합니다.

@unittest.skipIf(condition, reason)

condition이 참이면 데코레이트된 테스트를 건너뜁니다.

@unittest.skipUnless(condition, reason)

condition이 참이 아니면 데코레이트된 테스트를 건너뜁니다.

@unittest.expectedFailure

Mark the test as an expected failure or error. If the test fails or errors in the test function itself (rather than in one of the test fixture methods) then it will be considered a success. If the test passes, it will be considered a failure.

exception unittest.SkipTest(reason)

이 예외는 테스트를 건너뛰기 위해서 발생합니다.

보통은 이 예외를 직접 발생시키기보다는 TestCase.skipTest()나 건너뛰기 데코레이터를 사용할 수 있습니다.

건너뛰는 테스트는 테스트 전후로 setUp()이나 tearDown()를 실행하지 않을 것입니다. 건너뛰는 클래스는 setUpClass()나 tearDownClass()를 실행하지 않을 것입니다. 건너뛰는 모듈은 setUpModule()이나 tearDownModule()을 실행하지 않을 것입니다.

부분 테스트(subtest)를 사용하여 테스트 반복 구별 짓기

Added in version 3.4.

여러분의 테스트들이 아주 작은 부분에서만 다를 때, 예를 들어 몇몇 매개변수, unittest는 subTest() 컨텍스트 관리자를 사용하여 테스트 메서드의 바디 안에서 그것들은 구별 짓게 해줍니다.

예를 들어, 다음 테스트는:

class NumbersTest(unittest.TestCase):

    def test_even(self):
        """
        Test that numbers between 0 and 5 are all even.
        """
        for i in range(0, 6):
            with self.subTest(i=i):
                self.assertEqual(i % 2, 0)

다음의 출력을 만듭니다:

======================================================================
FAIL: test_even (__main__.NumbersTest.test_even) (i=1)
Test that numbers between 0 and 5 are all even.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 11, in test_even
    self.assertEqual(i % 2, 0)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 0

======================================================================
FAIL: test_even (__main__.NumbersTest.test_even) (i=3)
Test that numbers between 0 and 5 are all even.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 11, in test_even
    self.assertEqual(i % 2, 0)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 0

======================================================================
FAIL: test_even (__main__.NumbersTest.test_even) (i=5)
Test that numbers between 0 and 5 are all even.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 11, in test_even
    self.assertEqual(i % 2, 0)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 0

부분 테스트를 사용하지 않는다면 테스트 실행은 첫 번째 실패 후에 중단될 것이고 i 값이 표시되지 않기 때문에 에러를 진단하는 데 쉽지 않을 것입니다:

======================================================================
FAIL: test_even (__main__.NumbersTest.test_even)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 32, in test_even
    self.assertEqual(i % 2, 0)
AssertionError: 1 != 0

클래스와 함수

이 절은 unittest의 API를 심도 있게 설명합니다.

테스트 케이스

class unittest.TestCase(methodName='runTest')

TestCase 클래스의 인스턴스는 unittest 세계에서 논리적인 테스트 단위에 해당합니다. 이 클래스는 베이스 클래스로 사용되며, 특정 테스트는 구상 클래스로 구현됩니다. 이 클래스는 테스트 실행자가 테스트를 실행할 수 있는 인터페이스를 구현하고 테스트 코드가 검사하고 다양한 실패를 보고할 수 있는 메서드를 구현합니다.

TestCase의 각 인스턴스는 하나의 베이스 메서드: methodName이 지정하는 이름의 메서드를 실행할 것입니다. 대부분의 TestCase 사용에서, 당신은 methodName을 바꾸거나 기본 runTest() 메서드를 재구현하지 않을 것입니다.

버전 3.2에서 변경: methodName 제공 없이도 TestCase를 성공적으로 인스턴스화할 수 있습니다. 이것은 대화형 인터프리터에서 TestCase로 쉽게 실험을 할 수 있게 합니다.

TestCase 인스턴스는 3가지 메서드 그룹을 제공합니다: 한 그룹은 테스트를 실행하는 데 사용되고, 다른 한 그룹은 조건을 확인하고 실패를 보고하는 테스트 구현으로 사용되고, 몇몇 조회 메서드는 테스트 자체에 관한 정보를 수집할 수 있게 해줍니다.

첫 번째 그룹(테스트 실행) 안에 메서드는:

setUp()

테스트 픽스쳐를 준비하기 위해 호출되는 메서드입니다. 이 메서드는 테스트 메서드를 호출하기 바로 직전에 호출됩니다; AssertionError 또는 SkipTest이외의 이 메서드에서 발생한 모든 예외는 테스트 실패가 아닌 오류로 간주합니다. 기본 구현은 아무것도 하지 않습니다.

tearDown()

테스트 메서드가 불리고 결과가 기록되고 나서 바로 다음에 호출되는 메서드입니다. 테스트 메서드가 예외를 발생했더라도 이 메서드는 불립니다, 따라서 서브 클래스의 구현은 내부 상태를 확인하는 데 특별히 주의를 기울여야 합니다. AssertionError 또는 SkipTest이외의 이 메서드에서 발생하는 모든 예외는 테스트 실패가 아닌 오류로 간주합니다(따라서 보고된 오류의 총 숫자가 증가합니다). 이 메서드는 테스트 메서드의 결과물에 영향받지 않고 setUp()이 성공했을 때만 불립니다. 기본 구현은 아무것도 하지 않습니다.

setUpClass()

개별 클래스의 테스트들이 실행되기 전에 불리는 클래스 메서드입니다. setUpClass는 클래스만 인자로 받아 호출되고 classmethod()로 데코레이트해야 합니다:

@classmethod
def setUpClass(cls):
    ...

더 자세한 것은 클래스와 모듈 픽스쳐를 보십시오.

Added in version 3.2.

tearDownClass()

개별 클래스의 테스트들이 실행되고 난 뒤에 불리는 클래스 메서드입니다. tearDownClass는 클래스만 인자로 받아 호출되고 classmethod()로 데코레이트해야 합니다:

@classmethod
def tearDownClass(cls):
    ...

더 자세한 것은 클래스와 모듈 픽스쳐를 보십시오.

Added in version 3.2.

run(result=None)

테스트를 실행하고, result 인자로 전달된 TestResult에 결과를 수집합니다. 만약 result 인자가 전달 안 되거나 None이라면 임시 결과 객체를 (defaultTestResult() 메서드를 불러서) 생성하여 사용합니다. run() 호출자에게 결과 객체를 반환합니다.

단순히 TestCase 인스턴스를 호출하는 것으로 같은 효과를 볼 수 있습니다.

버전 3.3에서 변경: 기존 버전의 run은 결과를 반환하지 않았습니다. 인스턴스 호출 또한 그렇지 않았습니다.

skipTest(reason)

테스트 메서드나 setUp()에서 이것을 호출하면 현재 테스트를 건너뜁니다. 자세한 정보는 테스트 건너뛰기와 예상된 실패를 보십시오.

Added in version 3.1.

subTest(msg=None, **params)

둘러싼 코드 블록을 부분 테스트로서 실행하는 컨텍스트 관리자를 반환합니다. msg 및 params는 선택 사항이며 부분 테스트가 실패 할 때마다 표시되는 임의의 값으로 당신이 명확하게 알아보게 해줍니다.

테스트 케이스는 여러 개의 부분 테스트 선언을 포함할 수 있고, 그것들은 자유롭게 중첩될 수 있습니다.

자세한 정보는 부분 테스트(subtest)를 사용하여 테스트 반복 구별 짓기를 보십시오.

Added in version 3.4.

debug()

결과를 수집하지 않고 테스트를 실행합니다. 이것은 테스트에서 발생한 예외가 호출자로 전파될 수 있게 해서, 디버거 환경에서 테스트를 실행할 때 사용될 수 있습니다.

TestCase 클래스는 값을 검사하고 실패를 보고하기 위해 몇 개의 assert 메서드를 제공합니다. 다음 표는 보통 많이 사용되는 메서드들입니다(더 많은 assert 메서드는 표 아래를 보십시오):

메서드

검사하는 내용

추가된 버전

assertEqual(a, b)

a == b

assertNotEqual(a, b)

a != b

assertTrue(x)

bool(x) is True

assertFalse(x)

bool(x) is False

assertIs(a, b)

a is b

3.1

assertIsNot(a, b)

a is not b

3.1

assertIsNone(x)

x is None

3.1

assertIsNotNone(x)

x is not None

3.1

assertIn(a, b)

a in b

3.1

assertNotIn(a, b)

a not in b

3.1

assertIsInstance(a, b)

isinstance(a, b)

3.2

assertNotIsInstance(a, b)

not isinstance(a, b)

3.2

모든 assert 메서드는 msg 인자를 받을 수 있습니다, 만약 그것이 전달된다면 실패 시 에러 메시지로 사용됩니다(longMessage 도 참고하십시오). assertRaises(), assertRaisesRegex(), assertWarns(), assertWarnsRegex()는 컨텍스트 관리자로서 사용될 때만 그들에게 msg 키워드 인자를 전달할 수 있다는 점을 주의하십시오.

assertEqual(first, second, msg=None)

first와 second가 같은지 테스트합니다. 비교한 값이 같지 않으면 테스트는 실패할 것입니다.

추가로, 만약 first와 second가 정확히 같은 형(type)이고 list, tuple, dict, set, frozenset, str 이거나 addTypeEqualityFunc()에 등록된 서브 클래스 형 중 하나일 경우 더 유용한 기본 에러 메시지를 생성하기 위해 형-특화(type-specific) 동등성 함수가 불릴 것입니다(형-특화 메서드 목록을 참고하십시오).

버전 3.1에서 변경: 형-특화 동등성 함수가 자동으로 불리도록 추가

버전 3.2에서 변경: 문자열 비교를 위해서 assertMultiLineEqual()를 기본 형-특화 동등성 함수에 추가

assertNotEqual(first, second, msg=None)

first와 second가 같지 않은지 테스트합니다, 비교한 값이 같으면 테스트는 실패할 것입니다.

assertTrue(expr, msg=None)

assertFalse(expr, msg=None)

expr이 참(또는 거짓)인지 테스트합니다.

이것은 bool(expr) is True와 동등하고 expr is True와 동등하지 않다는 것에 주의하십시오(후자를 위해선 assertIs(expr, True)를 사용하십시오). 더 구체적인 메서드를 사용할 수 있을 때는 이 메서드를 지양해야 합니다(예, assertTrue(a == b) 대신에 assertEqual(a, b)), 왜냐하면 실패의 경우에 구체적인 메서드가 더 나은 에러 메시지를 제공하기 때문입니다.

assertIs(first, second, msg=None)

assertIsNot(first, second, msg=None)

first와 second가 같은 객체인지 (혹은 아닌지) 테스트합니다.

Added in version 3.1.

assertIsNone(expr, msg=None)

assertIsNotNone(expr, msg=None)

expr이 None 인지(아닌지) 테스트합니다.

Added in version 3.1.

assertIn(member, container, msg=None)

assertNotIn(member, container, msg=None)

member가 container 안에 있는지(아닌지) 테스트합니다.

Added in version 3.1.

assertIsInstance(obj, cls, msg=None)

assertNotIsInstance(obj, cls, msg=None)

obj가 cls(isinstance()가 지원하는 것처럼 클래스 또는 클래스의 튜플)의 인스턴스인지(아닌지) 테스트합니다. 정확한 형 검사를 위해서는 assertIs(type(obj), cls)를 사용하십시오.

Added in version 3.2.

다음의 메서드를 사용하여 예외, 경고, 로그 메시지의 발생을 검사할 수 있습니다:

메서드

검사하는 내용

추가된 버전

assertRaises(exc, fun, *args, **kwds)

fun(*args, **kwds)가 exc를 발생

assertRaisesRegex(exc, r, fun, *args, **kwds)

fun(*args, **kwds)가 exc를 발생하고 메시지가 정규식 r에 일치

3.1

assertWarns(warn, fun, *args, **kwds)

fun(*args, **kwds)가 warn을 발생

3.2

assertWarnsRegex(warn, r, fun, *args, **kwds)

fun(*args, **kwds)가 warn을 발생하고 메시지가 정규식 r에 일치

3.2

assertLogs(logger, level)

with 블록이 최소 level로 logger에 로그를 남김

3.4

assertNoLogs(logger, level)

The with block does not log on

logger with minimum level

3.10

assertRaises(exception, callable, *args, **kwds)

assertRaises(exception, *, msg=None)

assertRaises()에 전달된 어떤 위치 또는 키워드 인자와 함께 callable이 호출되었을 때 예외가 발생하는지 테스트합니다. exception이 발생하면 테스트를 통과하고, 다른 예외가 발생하면 에러이고, 아무 예외도 발생하지 않으면 실패입니다. 여러 예외 모음을 잡기 위해서 예외 클래스를 포함한 튜플을 exception으로 전달해도 좋습니다.

만약 선택적인 msg와 함께 오직 exception 인자만 전달된다면, 테스트할 코드를 함수가 아닌 인라인으로 작성할 수 있도록 컨텍스트 관리자를 반환합니다:

with self.assertRaises(SomeException):
    do_something()

컨텍스트 관리자로 사용되면, assertRaises()는 추가적인 키워드 인자인 msg를 받을 수 있습니다.

컨텍스트 관리자는 잡은 예외 객체를 exception 어트리뷰트에 저장할 것입니다. 이것은 발생한 예외에 대해서 추가적인 검사를 수행하려는 경우에 유용할 수 있습니다:

with self.assertRaises(SomeException) as cm:
    do_something()

the_exception = cm.exception
self.assertEqual(the_exception.error_code, 3)

버전 3.1에서 변경: assertRaises()를 컨텍스트 관리자로 사용할 수 있도록 기능 추가.

버전 3.2에서 변경: exception 어트리뷰트 추가.

버전 3.3에서 변경: 컨텍스트 관리자로 사용될 때 msg 키워드 인자 추가.

assertRaisesRegex(exception, regex, callable, *args, **kwds)

assertRaisesRegex(exception, regex, *, msg=None)

assertRaises()와 비슷하지만 발생한 예외의 문자열 표현이 regex에 일치하는지 테스트합니다. regex는 정규식 객체나 re.search()에 사용되기 적합한 정규식 문자열이 될 수 있습니다. 예:

self.assertRaisesRegex(ValueError, "invalid literal for.*XYZ'$",
                       int, 'XYZ')

또는:

with self.assertRaisesRegex(ValueError, 'literal'):
   int('XYZ')

Added in version 3.1: assertRaisesRegexp 라는 이름으로 추가되었습니다.

버전 3.2에서 변경: assertRaisesRegex()으로 이름 변경.

버전 3.3에서 변경: 컨텍스트 관리자로 사용될 때 msg 키워드 인자 추가.

assertWarns(warning, callable, *args, **kwds)

assertWarns(warning, *, msg=None)

assertWarns()에 전달된 어떤 위치 또는 키워드 인자와 함께 callable이 호출되었을 때 경고(warning)가 발생하는지 테스트합니다. warning이 발생하면 테스트를 통과하고, 그렇지 않으면 실패입니다. 예외가 발생하면 에러입니다. 여러 경고 모음을 잡기 위해서 경고 클래스를 포함한 튜플을 warnings로 전달해도 좋습니다.

만약 선택적인 msg와 함께 오직 warning 인자만 전달된다면, 테스트할 코드를 함수가 아닌 인라인으로 작성할 수 있도록 컨텍스트 관리자를 반환합니다:

with self.assertWarns(SomeWarning):
    do_something()

컨텍스트 관리자로 사용되면, assertWarns()는 추가적인 키워드 인자인 msg를 받을 수 있습니다.

컨텍스트 관리자는 잡은 경고 객체를 warning 어트리뷰트에 저장하고, 경고를 발생한 소스코드 줄을 filename과 lineno에 저장할 것입니다. 이것은 발생한 경고에 대해서 추가적인 검사를 수행하려는 경우에 유용할 수 있습니다:

with self.assertWarns(SomeWarning) as cm:
    do_something()

self.assertIn('myfile.py', cm.filename)
self.assertEqual(320, cm.lineno)

이 메서드는 호출될 때 적용될 경고 필터와 관계없이 작동합니다.

Added in version 3.2.

버전 3.3에서 변경: 컨텍스트 관리자로 사용될 때 msg 키워드 인자 추가.

assertWarnsRegex(warning, regex, callable, *args, **kwds)

assertWarnsRegex(warning, regex, *, msg=None)

assertWarns()와 비슷하지만 발생한 경고의 메시지가 regex에 일치하는지 테스트합니다. regex는 정규식 객체나 re.search()에 사용되기 적합한 정규식 문자열이 될 수 있습니다. 예:

self.assertWarnsRegex(DeprecationWarning,
                      r'legacy_function\(\) is deprecated',
                      legacy_function, 'XYZ')

또는:

with self.assertWarnsRegex(RuntimeWarning, 'unsafe frobnicating'):
    frobnicate('/etc/passwd')

Added in version 3.2.

버전 3.3에서 변경: 컨텍스트 관리자로 사용될 때 msg 키워드 인자 추가.

assertLogs(logger=None, level=None)

최소한 level로 logger나 그 자식들에 최소한 1개의 메시지가 기록되는지 테스트하는 컨텍스트 관리자입니다.

logger가 주어졌다면, logging.Logger 객체이거나 로거의 이름인 str이어야 합니다. 기본값은 전파하지 않는 하위 로거에 의해 차단되지 않은 모든 메시지를 잡을 루트 로거입니다.

If given, level should be either a numeric logging level or its string equivalent (for example either "ERROR" or logging.ERROR). The default is logging.INFO.

만약 with 블록 안에서 logger와 level 조건을 만족하는 최소한 1개의 메시지가 나왔다면 테스트는 성공하고, 그렇지 않으면 실패합니다.

컨텍스트 관리자에 의해 반환되는 객체는 조건에 일치하는 로그 메시지를 추적하기 위한 기록 도우미입니다. 이것은 2개의 어트리뷰트를 가지고 있습니다:

records

조건에 일치하는 메시지의 logging.LogRecord 객체 목록.

output

조건에 일치하는 메시지의 포맷 출력인 str 객체 목록.

예:

with self.assertLogs('foo', level='INFO') as cm:
    logging.getLogger('foo').info('first message')
    logging.getLogger('foo.bar').error('second message')
self.assertEqual(cm.output, ['INFO:foo:first message',
                             'ERROR:foo.bar:second message'])

Added in version 3.4.

assertNoLogs(logger=None, level=None)

A context manager to test that no messages are logged on the logger or one of its children, with at least the given level.

If given, logger should be a logging.Logger object or a str giving the name of a logger. The default is the root logger, which will catch all messages.

If given, level should be either a numeric logging level or its string equivalent (for example either "ERROR" or logging.ERROR). The default is logging.INFO.

Unlike assertLogs(), nothing will be returned by the context manager.

Added in version 3.10.

더 구체적인 검사를 수행하기 위한 또 다른 메서드가 있습니다, 아래와 같이:

메서드

검사하는 내용

추가된 버전

assertAlmostEqual(a, b)

round(a-b, 7) == 0

assertNotAlmostEqual(a, b)

round(a-b, 7) != 0

assertGreater(a, b)

a > b

3.1

assertGreaterEqual(a, b)

a >= b

3.1

assertLess(a, b)

a < b

3.1

assertLessEqual(a, b)

a <= b

3.1

assertRegex(s, r)

r.search(s)

3.1

assertNotRegex(s, r)

not r.search(s)

3.2

assertCountEqual(a, b)

순서와 상관없이 a와 b가 같은 개수의 같은 요소를 가졌는지.

3.2

assertAlmostEqual(first, second, places=7, msg=None, delta=None)

assertNotAlmostEqual(first, second, places=7, msg=None, delta=None)

first와 second가 근사하게 같은지(또는 근사하게 같지 않은지) 테스트합니다. 이는 값 차이를 계산하고, 주어진 소수 자릿(places)수(기본값 7)로 반올림한 뒤, 0과 비교하는 것으로 이루어집니다. 이 메서드는 값을 유효 숫자 자릿수(significant digits)가 아닌 주어진 소수 자릿수(decimal places)(즉, round() 함수와 같이)로 반올림합니다.

만약 places 대신에 delta가 주어진다면 first와 second의 값 차이는 반드시 delta보다 작거나 같아야(또는 커야) 합니다.

delta와 places가 동시에 주어지면 TypeError가 발생합니다.

버전 3.2에서 변경: assertAlmostEqual()은 같다고 비교되는 거의 동등한 객체를 자동으로 고려합니다. assertNotAlmostEqual()은 객체가 같다고 비교되면 자동으로 실패합니다. delta 키워드 인자를 추가.

assertGreater(first, second, msg=None)

assertGreaterEqual(first, second, msg=None)

assertLess(first, second, msg=None)

assertLessEqual(first, second, msg=None)

first를 second와 비교해서 각각 메서드 이름에 해당하는 >, >=, <, <= 인지 테스트합니다. 그렇지 않으면 테스트는 실패합니다:

>>> self.assertGreaterEqual(3, 4)
AssertionError: "3" unexpectedly not greater than or equal to "4"

Added in version 3.1.

assertRegex(text, regex, msg=None)

assertNotRegex(text, regex, msg=None)

regex 검색이 text에 일치하는지(아닌지) 테스트합니다. 실패의 경우, 에러 메시지는 패턴과 text(또는 패턴과 예상과 달리 일치한 text의 부분)를 포함할 것입니다. regex는 정규식 객체나 re.search()에 사용되기 적합한 정규식 문자열이 될 수 있습니다.

Added in version 3.1: assertRegexpMatches 라는 이름으로 추가되었습니다.

버전 3.2에서 변경: assertRegexpMatches() 메서드가 assertRegex()로 이름 변경되었습니다.

Added in version 3.2: assertNotRegex().

assertCountEqual(first, second, msg=None)

first 시퀀스가 순서에 상관없이 second와 같은 요소를 포함하는지 테스트합니다. 그렇지 않은 경우, 시퀀스들의 차이를 나열한 에러 메시지가 생성됩니다.

first와 second를 비교할 때 중복된 요소는 무시하지 않습니다. 두 개의 시퀀스에 각 요소가 같은 수 만큼 있는 것을 확인합니다. assertEqual(Counter(list(first)), Counter(list(second)))와 같지만 해시 불가능한(unhashable) 시퀀스에도 작동합니다.

Added in version 3.2.

assertEqual() 메서드는 같은 형의 객체의 동등성 검사를 다른 형-특화 메서드에게로 보냅니다. 이러한 메서드들은 대부분의 내장 형에 대해서 이미 구현되어 있지만, addTypeEqualityFunc()을 사용하여 새로운 메서드를 등록하는 것도 가능합니다:

addTypeEqualityFunc(typeobj, function)

정확히 같은 (서브 클래스가 아닌) typeobj 형의 두 객체가 같은지 비교 검사하기 위해 assertEqual()한테 불리는 형-특화 메서드를 등록합니다. function은 반드시 2개의 위치 인자를 받아야 하고 assertEqual()이 그러한 것처럼 msg=None 키워드 인자를 세 번째로 받아야 합니다. 이것은 처음 2개의 매개변수가 같지 않은 것이 확인될 경우 self.failureException(msg)을 반드시 발생시켜야 합니다 – 에러 메시지에 유용한 정보를 제공하고 비동등성을 자세히 설명할 수 있을 것입니다.

Added in version 3.1.

assertEqual()에서 자동으로 사용하는 형-특화 메서드 목록은 다음 표에 정리되어 있습니다. 보통은 이 메서드를 직접 부를 필요가 없다는 것을 기억하십시오.

메서드

을 비교하기 위해

추가된 버전

assertMultiLineEqual(a, b)

문자열

3.1

assertSequenceEqual(a, b)

시퀀스

3.1

assertListEqual(a, b)

리스트

3.1

assertTupleEqual(a, b)

튜플

3.1

assertSetEqual(a, b)

집합 또는 불변 집합

3.1

assertDictEqual(a, b)

딕셔너리

3.1

assertMultiLineEqual(first, second, msg=None)

여러 줄 문자열인 first와 second가 같은지 테스트합니다. 같지 않을 경우 에러 메시지에 다른 부분이 강조된 두 문자열의 차이가 포함됩니다. 이 메서드는 assertEqual()에서 문자열을 비교할 때 기본적으로 사용됩니다.

Added in version 3.1.

assertSequenceEqual(first, second, msg=None, seq_type=None)

2개의 시퀀스가 같은지 테스트합니다. seq_type이 전달된 경우, first와 second 둘 다 seq_type의 인스턴스이어야 하고 그렇지 않은 경우 실패가 발생합니다. 시퀀스가 다른 경우, 에러 메시지는 2개 사이의 차이점을 보여주게 됩니다.

이 메서드는 assertEqual()에서 직접 호출되진 않지만, assertListEqual()와 assertTupleEqual()을 구현할 때 사용됩니다.

Added in version 3.1.

assertListEqual(first, second, msg=None)

assertTupleEqual(first, second, msg=None)

2개의 리스트나 튜플이 같은지 테스트합니다. 만약 같지 않다면 에러 메시지는 2개 사이의 차이점만 보여주게 됩니다. 매개변수 중 하나가 잘못된 형인 경우 에러가 발생합니다. 이 메서드는 assertEqual()에서 리스트와 튜플을 비교할 때 기본적으로 사용됩니다.

Added in version 3.1.

assertSetEqual(first, second, msg=None)

2개의 집합이 같은지 테스트합니다. 같지 않은 경우 에러 메시지는 집합 사이의 차이를 나열하게 됩니다. 이 메서드는 assertEqual()에서 집합이나 불변 집합을 비교할 때 기본적으로 사용됩니다.

first와 second 중 하나가 set.difference() 메서드를 가지고 있지 않으면 실패합니다.

Added in version 3.1.

assertDictEqual(first, second, msg=None)

2개의 딕셔너리가 같은지 테스트합니다. 같지 않은 경우 에러 메시지는 딕셔너리 사이의 차이를 보여주게 됩니다. 이 메서드는 assertEqual()에서 딕셔너리를 비교할 때 기본적으로 사용될 것입니다.

Added in version 3.1.

마지막으로 TestCase가 다음의 메서드와 어트리뷰트를 제공합니다:

fail(msg=None)

무조건 테스트 실패 신호를 보냅니다, 에러 메시지를 위해 msg나 None을 전달합니다.

failureException

이 클래스 어트리뷰트는 테스트 메서드에서 발생한 예외를 줍니다. 만약 테스트 프레임워크가 추가 정보를 전달하기 위해 특수한 예외를 사용할 필요가 있다면, 프레임워크와 “공정하게 행동하기” 위해서 이 예외를 서브 클래스해야 합니다. 이 어트리뷰트의 초깃값은 AssertionError 입니다.

longMessage

이 클래스 어트리뷰트는 실패한 assertXYY 호출에 msg 인자로 전달된 사용자 정의 실패 메시지가 어떻게 동작하는지를 결정합니다. True가 기본값입니다. 이 경우, 사용자 정의 메시지가 표준 실패 메시지 끝에 추가됩니다. False로 설정할 경우 사용자 정의 메시지가 표준 메시지를 대체합니다.

이 클래스 설정은 인스턴스 어트리뷰트를 설정하여 개별 테스트 메서드에 의해 재정의될 수 있습니다, assert 메서드를 호출하기 전에 self.longMessage를 True 또는 False로 설정하는 것입니다.

이 클래스 설정은 각 테스트 호출 전에 재설정됩니다.

Added in version 3.1.

maxDiff

이 어트리뷰트는 실패 시 diff를 보고하는 assert 메서드의 최대 diff 출력 길이를 설정합니다. 기본값은 80*8 문자입니다. 이 어트리뷰트에 영향을 받는 assert 메서드는 assertSequenceEqual()(이것에 위임하는 모든 시퀀스 비교 메서드를 포함), assertDictEqual(), assertMultiLineEqual() 입니다.

maxDiff를 None으로 설정하면 diff의 최대 길이 제한이 없어지는 것을 뜻합니다.

Added in version 3.2.

테스트 프레임워크는 테스트에 관한 정보를 수집하기 위해 다음의 메서드를 사용할 수 있습니다:

countTestCases()

이 테스트 객체에 해당하는 테스트 개수를 반환합니다. TestCase 인스턴스에 대해서는 이것은 항상 1입니다.

defaultTestResult()

이 테스트 케이스 클래스를 위해서 사용되는 테스트 결과 클래스의 인스턴스를 반환합니다(run() 메서드에 다른 결과 인스턴스가 전달되지 않은 경우에).

TestCase 인스턴스에 대해서는 이것은 항상 TestResult의 인스턴스입니다; TestCase의 서브 클래스는 이것을 필요에 따라 재정의해야 합니다.

id()

특정 테스트 케이스를 식별하는 문자열을 반환합니다. 이것은 보통 모듈과 클래스 이름을 포함한 테스트 메서드의 완전한 이름(full name)입니다.

shortDescription()

테스트의 설명을 반환하거나 설명이 제공되지 않았으면 None을 반환합니다. 이 메서드의 기본 구현은 가능하다면 테스트 메서드의 독스트링의 첫 번째 줄을 반환하고 그렇지 않으면 None을 반환합니다.

버전 3.1에서 변경: 3.1 버전에서 docstring이 있는 경우에도 짧은 설명에 테스트 이름을 추가하도록 변경되었습니다. 이것은 unittest 확장과 호환성 문제를 일으켰고 테스트 이름 추가는 파이썬 3.2에서 TextTestResult로 옮겨졌습니다.

addCleanup(function, /, *args, **kwargs)

테스트 중에 사용된 자원을 정리하기 위해 tearDown() 이후에 불리는 함수를 추가합니다. 함수들은 추가된 순서의 반대 순서대로 불리게 됩니다(LIFO). 함수가 추가될 때 addCleanup()에 같이 전달된 위치 인자나 키워드 인자와 함께 호출됩니다.

만약 setUp()이 실패한다면, 즉 tearDown()이 불리지 않더라도, 정리 함수들은 여전히 불리게 될 것입니다.

Added in version 3.1.

enterContext(cm)

Enter the supplied context manager. If successful, also add its __exit__() method as a cleanup function by addCleanup() and return the result of the __enter__() method.

Added in version 3.11.

doCleanups()

이 메서드는 tearDown() 이후나, setUp()이 예외를 발생시키면 setUp()이후에 조건 없이 호출됩니다.

addCleanup()에서 추가된 모든 정리 함수들을 호출하는 책임이 있습니다. 만약 정리 함수를 tearDown() 이전에 불러야 할 필요가 있다면 doCleanups()를 직접 부를 수 있습니다.

doCleanups()는 한 번에 하나씩 정리 함수 스택에서 메서드를 꺼내기 때문에 언제든지 호출될 수 있습니다.

Added in version 3.1.

classmethod addClassCleanup(function, /, *args, **kwargs)

테스트 클래스 중에 사용된 자원을 정리하기 위해 tearDownClass() 이후에 불리는 함수를 추가합니다. 함수들은 추가된 순서의 반대 순서대로 불리게 됩니다(LIFO). 함수가 추가될 때 addClassCleanup()에 같이 전달된 위치 인자나 키워드 인자와 함께 호출됩니다.

만약 setUpClass()가 실패한다면, 즉 tearDownClass()가 불리지 않더라도, 정리 함수들은 여전히 불리게 될 것입니다.

Added in version 3.8.

classmethod enterClassContext(cm)

Enter the supplied context manager. If successful, also add its __exit__() method as a cleanup function by addClassCleanup() and return the result of the __enter__() method.

Added in version 3.11.

classmethod doClassCleanups()

이 메서드는 tearDownClass() 이후나, setUpClass()이 예외를 발생시키면 setUpClass()이후에 조건 없이 호출됩니다.

addClassCleanup()에서 추가된 모든 정리 함수들을 호출하는 책임이 있습니다. 만약 정리 함수를 tearDownClass() 이전에 호출해야 할 필요가 있다면 doClassCleanups()를 직접 호출할 수 있습니다.

doClassCleanups()는 한 번에 하나씩 정리 함수 스택에서 메서드를 꺼내기 때문에 언제든지 호출될 수 있습니다.

Added in version 3.8.

class unittest.IsolatedAsyncioTestCase(methodName='runTest')

이 클래스는 TestCase와 유사한 API를 제공하며 코루틴을 테스트 함수로 받아들입니다.

Added in version 3.8.

loop_factory

The loop_factory passed to asyncio.Runner. Override in subclasses with asyncio.EventLoop to avoid using the asyncio policy system.

Added in version 3.13.

coroutine asyncSetUp()

테스트 픽스쳐를 준비하기 위해 호출되는 메서드입니다. 이 메서드는 setUp()이후에 호출됩니다. 이 메서드는 테스트 메서드를 호출하기 바로 직전에 호출됩니다; AssertionError 또는 SkipTest이외의 이 메서드에서 발생한 모든 예외는 테스트 실패가 아닌 오류로 간주합니다. 기본 구현은 아무것도 하지 않습니다.

coroutine asyncTearDown()

테스트 메서드가 불리고 결과가 기록되고 나서 바로 다음에 호출되는 메서드입니다. 이 메서드는 tearDown()전에 호출됩니다. 테스트 메서드가 예외를 발생했더라도 이 메서드는 불립니다, 따라서 서브 클래스의 구현은 내부 상태를 확인하는 데 특별히 주의를 기울여야 합니다. AssertionError 또는 SkipTest이외의 이 메서드에서 발생하는 모든 예외는 테스트 실패가 아닌 오류로 간주합니다(따라서 보고된 오류의 총 숫자가 증가합니다). 이 메서드는 테스트 메서드의 결과물에 영향받지 않고 asyncSetUp()이 성공했을 때만 불립니다. 기본 구현은 아무것도 하지 않습니다.

addAsyncCleanup(function, /, *args, **kwargs)

이 메서드는 정리 함수로 사용할 수 있는 코루틴을 받아들입니다.

coroutine enterAsyncContext(cm)

Enter the supplied asynchronous context manager. If successful, also add its __aexit__() method as a cleanup function by addAsyncCleanup() and return the result of the __aenter__() method.

Added in version 3.11.

run(result=None)

테스트를 실행하기 위한 새 이벤트 루프를 설정하고, result 인자로 전달된 TestResult에 결과를 수집합니다. 만약 result 인자가 전달 안 되거나 None이라면 임시 결과 객체를 (defaultTestResult() 메서드를 불러서) 생성하여 사용합니다. run() 호출자에게 결과 객체를 반환합니다. 테스트의 끝에서 이벤트 루프의 모든 태스크는 취소됩니다.

순서를 보여주는 예:

from unittest import IsolatedAsyncioTestCase

events = []

class Test(IsolatedAsyncioTestCase):

    def setUp(self):
        events.append("setUp")

    async def asyncSetUp(self):
        self._async_connection = await AsyncConnection()
        events.append("asyncSetUp")

    async def test_response(self):
        events.append("test_response")
        response = await self._async_connection.get("https://example.com")
        self.assertEqual(response.status_code, 200)
        self.addAsyncCleanup(self.on_cleanup)

    def tearDown(self):
        events.append("tearDown")

    async def asyncTearDown(self):
        await self._async_connection.close()
        events.append("asyncTearDown")

    async def on_cleanup(self):
        events.append("cleanup")

if __name__ == "__main__":
    unittest.main()

테스트를 실행한 후, events에는 ["setUp", "asyncSetUp", "test_response", "asyncTearDown", "tearDown", "cleanup"]가 포함됩니다.

class unittest.FunctionTestCase(testFunc, setUp=None, tearDown=None, description=None)

이 클래스는 테스트 실행자가 테스트를 수행할 수 있게 TestCase 인터페이스 일부를 구현합니다, 하지만 테스트 코드가 검사하거나 에러를 보고하는 데 사용하는 메서드를 제공하지는 않습니다. 이것은 레거시 테스트 코드를 사용하여 테스트 케이스를 생성할 때 사용할 수 있습니다, 이것은 레거시 테스트 코드가 unittest-기반 테스트 프레임워크에 통합될 수 있게 해줍니다.

테스트 분류

class unittest.TestSuite(tests=())

이 클래스는 개별 테스트 케이스와 테스트 묶음의 집합체를 나타냅니다. 이 클래스는 테스트 실행자가 이것을 다른 테스트 케이스처럼 실행할 수 있기 위해 필요한 인터페이스를 제공합니다. TestSuite 인스턴스를 실행하는 것은 테스트 묶음을 이터레이션하면서 각 테스트를 개별적으로 실행하는 것과 같습니다.

tests가 주어졌다면, 그것은 초기에 이 테스트 묶음을 만들 때 사용될 개별 테스트 케이스이거나 다른 테스트 묶음의 이터러블이어야 합니다. 나중에 컬렉션에 테스트 케이스나 테스트 묶음을 추가할 수 있는 추가 메서드가 제공됩니다.

TestSuite 객체는 TestCase 객체와 흡사하게 행동합니다만, 테스트를 실제로 구현하지 않는 것이 다릅니다. 대신에, 이것은 다 같이 실행되어야 하는 테스트 그룹에 테스트들을 모으는 데 사용됩니다. TestSuite 인스턴스에 테스트를 추가하기 위해 몇몇 추가적인 메서드를 사용할 수 있습니다.

addTest(test)

테스트 묶음에 TestCase나 TestSuite 추가하기.

addTests(tests)

이 테스트 묶음에 TestCase와 TestSuite 인스턴스의 이터러블에서 나온 모든 테스트를 추가하기.

이것은 tests를 이터레이션하면서 각 요소에 대해 addTest()를 호출하는 것과 같습니다.

TestSuite는 다음 메서드를 TestCase와 공유합니다:

run(result)

이 테스트 묶음과 연관된 테스트를 실행하고, result로 전달된 테스트 결과 객체에 결과를 수집합니다. TestCase.run()과 달리 TestSuite.run()은 결과 객체가 반드시 전달되어야 합니다.

debug()

결과를 수집하지 않고 이 테스트 묶음과 연관된 테스트를 실행합니다. 이것은 테스트에서 발생한 예외가 호출자로 전파될 수 있게 해서 디버거 환경에서 테스트를 실행할 때 사용될 수 있습니다.

countTestCases()

이 테스트 객체에 해당하는 테스트 개수를 반환합니다, 모든 개별 테스트와 서브-테스트 묶음을 포함합니다.

__iter__()

Tests grouped by a TestSuite are always accessed by iteration. Subclasses can lazily provide tests by overriding __iter__(). Note that this method may be called several times on a single suite (for example when counting tests or comparing for equality) so the tests returned by repeated iterations before TestSuite.run() must be the same for each call iteration. After TestSuite.run(), callers should not rely on the tests returned by this method unless the caller uses a subclass that overrides TestSuite._removeTestAtIndex() to preserve test references.

버전 3.2에서 변경: In earlier versions the TestSuite accessed tests directly rather than through iteration, so overriding __iter__() wasn’t sufficient for providing tests.

버전 3.4에서 변경: 이전 버전에서는 TestSuite가 TestSuite.run() 후에 각 TestCase 의 참조를 유지했습니다. 서브 클래스는 TestSuite._removeTestAtIndex()를 재정의해서 이 동작을 복구할 수 있습니다.

TestSuite 객체의 전형적인 사용법은 최종 사용자 테스트 장치(harness)보다는 TestRunner에 의해 run() 메서드가 호출되는 것입니다.

테스트를 로드하고 실행하기

class unittest.TestLoader

TestLoader 클래스는 클래스와 모듈로부터 테스트 묶음을 생성하는 데 사용됩니다. 보통, 이 클래스의 인스턴스를 생성할 필요는 없습니다; unittest 모듈은 공유 가능한 unittest.defaultTestLoader 인스턴스를 제공합니다. 그러나 서브 클래스나 인스턴스를 사용함으로 몇몇 변경 가능한 속성을 사용자 정의할 수 있습니다.

TestLoader 객체는 다음 어트리뷰트를 가집니다:

errors

A list of the non-fatal errors encountered while loading tests. Not reset by the loader at any point. Fatal errors are signalled by the relevant method raising an exception to the caller. Non-fatal errors are also indicated by a synthetic test that will raise the original error when run.

Added in version 3.5.

TestLoader 객체는 다음 메서드를 가집니다:

loadTestsFromTestCase(testCaseClass)

TestCase에서 파생된 testCaseClass에 포함된 모든 테스트 케이스의 묶음을 반환합니다.

테스트 케이스 인스턴스는 getTestCaseNames()에 의해 이름 지어진 각 메서드를 위해 생성됩니다. 기본값은 test로 시작되는 메서드 이름입니다. 만약 getTestCaseNames()가 아무 메서드도 반환하지 않지만, runTest() 메서드가 구현되었다면 이 메서드를 위해서 1개의 테스트 케이스가 대신 생성됩니다.

loadTestsFromModule(module, *, pattern=None)

주어진 모듈에 포함된 모든 테스트 케이스 묶음을 반환합니다. 이 메서드는 TestCase에서 파생된 클래스를 찾기 위해 module을 검색하고 클래스에 정의된 각 테스트 메서드를 위해 클래스의 인스턴스를 생성합니다.

참고

TestCase에서 파생된 클래스의 계층 사용이 픽스쳐와 도우미 함수를 공유하는 데 편리할 수 있지만 직접 인스턴스화를 하도록 의도되지 않은 베이스 클래스에 테스트 메서드를 정의하는 것은 이 메서드와 잘 작동하지 않습니다. 그러나 그렇게 하는 것이 픽스처들이 다르고 서브 클래스에서 정의될 경우에는 유용할 수 있습니다.

만약 모듈이 load_tests 함수를 제공한다면 테스트 로드를 위해 이것을 호출할 것입니다. 이것은 모듈이 테스트 로드를 사용자 정의할 수 있도록 해줍니다. 이것은 load_tests 프로토콜입니다. pattern 인자는 load_tests에 세 번째 인자로 전달됩니다.

버전 3.2에서 변경: load_tests 지원이 추가됨.

버전 3.5에서 변경: Support for a keyword-only argument pattern has been added.

버전 3.12에서 변경: The undocumented and unofficial use_load_tests parameter has been removed.

loadTestsFromName(name, module=None)

문자열 지정자에 맞는 모든 테스트 케이스 묶음을 반환합니다.

지정자 name은 모듈, 테스트 케이스 클래스, 테스트 케이스 클래스에 있는 테스트 메서드, TestSuite 인스턴스, TestCase나 TestSuite 인스턴스를 반환하는 콜러블 객체로 해석될 수 있는 “점으로 구분된 이름(dotted name)”입니다. 이 검사는 여기에 나열된 순서대로 적용됩니다; 즉, 테스트 케이스 클래스에 있는 메서드는 “콜러블 객체”보다는 “테스트 케이스 클래스에 있는 테스트 메서드”로 선택될 것입니다.

예를 들어, 만약 당신이 TestCase에서 파생된 클래스인 SampleTestCase를 포함한 SampleTests 모듈을 가지고 있고 그 클래스는 3개의 테스트 메서드(test_one(), test_two(), test_three())를 가지고 있다면, 지정자 'SampleTests.SampleTestCase' 에 대해서 이 메서드는 모든 3개의 테스트 메서드를 실행할 테스트 묶음으로 반환할 것입니다. 지정자가 'SampleTests.SampleTestCase.test_two' 라면 이 메서드는 오직 test_two() 테스트 메서드를 실행할 테스트 묶음을 반환할 것입니다. 지정자는 아직 임포트되지 않은 모듈이나 패키지를 가리킬 수 있습니다; 부작용(side-effect)으로써 그것들이 임포트될 것입니다.

이 메서드는 주어진 module에 상대적인 name을 선택적으로 해석할 수 있습니다.

버전 3.5에서 변경: 만약 name 순회 중에 ImportError나 AttributeError가 발생한다면 실행할 때 그 에러를 일으키는 합성 테스트가 반환될 것입니다. 이 에러는 self.errors 에러 모임에 포함될 것입니다.

loadTestsFromNames(names, module=None)

loadTestsFromName()와 비슷하지만, 1개의 이름이 아닌 이름의 시퀀스를 받습니다. 반환 값은 각 이름에 정의된 모든 테스트를 지원하는 테스트 묶음입니다.

getTestCaseNames(testCaseClass)

testCaseClass 안에서 찾은 메서드 이름을 정렬된 시퀀스로 반환합니다; 이 클래스는 TestCase의 서브 클래스이어야 합니다.

discover(start_dir, pattern='test*.py', top_level_dir=None)

지정된 시작 디렉터리부터 하위 디렉터리를 재귀적으로 순회하여 모든 테스트 모듈을 찾아, 이를 포함하는 TestSuite 객체를 반환합니다. pattern에 일치하는 테스트 파일만 로드될 것입니다. (셸 방식의 패턴 일치를 사용합니다.) 임포트 가능한(즉, 유효한 파이썬 식별자인) 모듈 이름만 로드될 것입니다.

All test modules must be importable from the top level of the project. If the start directory is not the top level directory then top_level_dir must be specified separately.

만약 모듈 임포트가 실패한다면, 예를 들어 문법 에러로 인해, 이것은 1개의 에러로 기록되고 탐색이 계속 진행될 것입니다. 만약 SkipTest가 발생해서 임포트가 실패했다면, 이것은 에러가 아닌 건너뛰기로 기록될 것입니다.

만약 패키지(__init__.py 라는 이름의 파일을 포함한 디렉터리)를 찾으면, load_tests 함수가 있는지 패키지를 검사할 것입니다. 만약 존재한다면 그 패키지에 대해서 package.load_tests(loader, tests, pattern)가 불릴 것입니다. 만약 load_tests 함수 자체가 loader.discover를 호출할지라도, 테스트 탐색은 실행 중에 패키지에 대한 테스트 검사를 한 번만 실행하도록 보장합니다.

만약 load_tests가 존재한다면 탐색은 패키지 안을 재귀 탐색하지 않습니다. load_tests가 패키지 안의 모든 테스트를 로드할 책임이 있습니다.

The pattern is deliberately not stored as a loader attribute so that packages can continue discovery themselves.

top_level_dir is stored internally, and used as a default to any nested calls to discover(). That is, if a package’s load_tests calls loader.discover(), it does not need to pass this argument.

start_dir는 디렉터리뿐만 아니라 점으로 구분된 모듈 이름이 될 수 있습니다.

Added in version 3.2.

버전 3.4에서 변경: 임포트 할 때 SkipTest를 발생시키는 모듈은 에러가 아니라 건너뛰기로 기록됩니다.

start_dir은 이름 공간 패키지일 수 있습니다.

임포트되기 전에 경로들이 정렬되어 하부 파일 시스템의 정렬 순서가 파일 이름에 의존하지 않더라도 실행 순서가 같아지도록 합니다.

버전 3.5에서 변경: 이제 발견된 패키지는 그것의 경로가 pattern과 일치하는지 여부와 상관없이 load_tests를 검사합니다, 왜냐하면 패키지 이름이 기본 패턴과 일치하는 것이 불가능하기 때문입니다.

버전 3.11에서 변경: start_dir can not be a namespace packages. It has been broken since Python 3.7, and Python 3.11 officially removes it.

버전 3.13에서 변경: top_level_dir is only stored for the duration of discover call.

버전 3.14에서 변경: start_dir can once again be a namespace package.

TestLoader의 다음 어트리뷰트들은 서브 클래스나 인스턴스에 대입을 통해 구성할 수 있습니다.

testMethodPrefix

테스트 메서드로 해석할 메서드 이름의 접두사에 해당하는 문자열입니다. 기본값은 'test' 입니다.

This affects getTestCaseNames() and all the loadTestsFrom* methods.

sortTestMethodsUsing

Function to be used to compare method names when sorting them in getTestCaseNames() and all the loadTestsFrom* methods.

suiteClass

테스트 목록에서 테스트 묶음을 생성하는 콜러블 객체입니다. 결과 객체에 어떤 메서드도 필요하지 않습니다. 기본값은 TestSuite 클래스입니다.

This affects all the loadTestsFrom* methods.

testNamePatterns

List of Unix shell-style wildcard test name patterns that test methods have to match to be included in test suites (see -k option).

If this attribute is not None (the default), all test methods to be included in test suites must match one of the patterns in this list. Note that matches are always performed using fnmatch.fnmatchcase(), so unlike patterns passed to the -k option, simple substring patterns will have to be converted using * wildcards.

This affects all the loadTestsFrom* methods.

Added in version 3.7.

class unittest.TestResult

어떤 테스트가 성공했고 어떤 테스트가 실패했는지에 관한 정보를 엮는데 사용되는 클래스입니다.

TestResult 객체는 여러 테스트의 결과들을 저장합니다. TestCase와 TestSuite 클래스는 결과가 올바르게 기록되는 것을 보장합니다; 테스트 작성자가 테스트 결과를 기록하는 것에 대해서 걱정할 필요가 없습니다.

unittest 위에 만들어진 테스트 프레임워크는 보고 목적으로 여러 테스트가 실행하면서 만들어낸 TestResult 객체에 접근하고 싶을 수도 있습니다; TestRunner.run() 메서드는 이 목적을 위해 TestResult 인스턴스를 반환합니다.

TestResult 인스턴스는 테스트 실행 결과를 조사할 때 관심이 생길만한 다음과 같은 어트리뷰트를 가지고 있습니다.

errors

TestCase 인스턴스와 포맷된(formatted) 트레이스백 문자열로 구성된 2-튜플을 포함하는 목록입니다. 각 튜플은 예기치 못한 예외가 발생한 테스트에 해당합니다.

failures

A list containing 2-tuples of TestCase instances and strings holding formatted tracebacks. Each tuple represents a test where a failure was explicitly signalled using the assert* methods.

skipped

TestCase 인스턴스와 테스트 건너뛰기한 이유 문자열로 구성된 2-튜플을 포함하는 목록입니다.

Added in version 3.1.

expectedFailures

TestCase 인스턴스와 포맷된(formatted) 트레이스백 문자열로 구성된 2-튜플을 포함하는 목록입니다. 각 튜플은 테스트 케이스의 예상된 실패니 에러에 해당합니다.

unexpectedSuccesses

예상된 실패로 표시되었지만 성공한 TestCase 인스턴스를 포함하는 목록입니다.

collectedDurations

A list containing 2-tuples of test case names and floats representing the elapsed time of each test which was run.

Added in version 3.12.

shouldStop

테스트 실행이 stop()에 의해 정지되어야 할 때 True로 설정합니다.

testsRun

이제까지 실행된 테스트 총 개수입니다.

buffer

참으로 설정하면 sys.stdout와 sys.stderr가 startTest()와 stopTest() 호출 사이에서 버퍼링될 것입니다. 수집된 출력은 테스트가 실패하거나 에러가 발생한 경우에만 실제 sys.stdout와 sys.stderr에 출력될 것입니다. 모든 출력은 실패 / 에러 메시지에도 첨부됩니다.

Added in version 3.2.

failfast

참으로 설정하면 첫 번째 실패 또는 에러에서 stop()이 호출될 것입니다.

Added in version 3.2.

tb_locals

참으로 설정하면 지역 변수가 트레이스백에 보일 것입니다.

Added in version 3.5.

wasSuccessful()

이제까지 실행한 모든 테스트가 성공했다면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

버전 3.4에서 변경: expectedFailure() 데코레이터로 표시된 테스트에서 unexpectedSuccesses가 있다면 False를 반환합니다.

stop()

shouldStop 어트리뷰트를 True로 설정하여 현재 실행 중인 테스트 모음을 중단해야 함을 알리기 위한 용도로 이 메서드를 부를 수 있습니다. TestRunner 객체는 이 신호를 존중하여 어떠한 추가 테스트 없이 반환해야 합니다.

예를 들어, 사용자가 키보드로 중단 신호를 보낼 때 테스트 프레임워크를 중단하기 위해 TextTestRunner가 이 기능을 사용합니다. TestRunner 구현을 제공하는 대화형 도구는 비슷한 방법으로 이것을 사용할 수 있습니다.

TestResult 클래스의 다음 메서드는 내부 자료 구조를 관리하려고 사용되고, 추가적인 보고 요구사항을 지원하기 위해 서브 클래스에서 확장할 수도 있습니다. 이것은 테스트가 실행 중에 대화형 보고를 지원하는 도구를 만들 때 특별히 유용합니다.

startTest(test)

테스트 케이스 test가 막 실행되려 할 때 호출됩니다.

stopTest(test)

결과에 상관없이 테스트 케이스 test가 실행되고 나서 호출됩니다.

startTestRun()

모든 테스트가 실행되기 전에 1번 호출됩니다.

Added in version 3.1.

stopTestRun()

모든 테스트가 실행되고 나서 1번 호출됩니다.

Added in version 3.1.

addError(test, err)

테스트 케이스 test가 예기치 못한 예외를 발생한 경우 호출됩니다. err는 sys.exc_info()가 반환한 형식의 튜플입니다: (type, value, traceback).

기본 구현은 (test, formatted_err) 튜플을 인스턴스의 errors 어트리뷰트에 추가합니다, 여기서 formatted_err는 err에서 파생된 포맷한 트레이스백입니다.

addFailure(test, err)

테스트 케이스 test가 실패 신호를 보낸 경우 호출됩니다. err는 sys.exc_info()가 반환한 형식의 튜플입니다: (type, value, traceback).

기본 구현은 (test, formatted_err) 튜플을 인스턴스의 failures 어트리뷰트에 추가합니다, 여기서 formatted_err는 err에서 파생된 포맷한 트레이스백입니다.

addSuccess(test)

테스트 케이스 test가 성공하면 호출됩니다.

기본 구현은 아무것도 하지 않습니다.

addSkip(test, reason)

테스트 케이스 test가 건너뛰어지면 호출됩니다. reason은 테스트가 준 건너뛰는 이유입니다.

기본 구현은 (test, reason) 튜플을 인스턴스의 skipped 어트리뷰트에 추가합니다.

addExpectedFailure(test, err)

테스트 케이스 test가 실패하거나 에러지만, expectedFailure() 데코레이터로 표시된 경우 호출됩니다

기본 구현은 (test, formatted_err) 튜플을 인스턴스의 expectedFailures 어트리뷰트에 추가합니다, 여기서 formatted_err는 err에서 파생된 포맷한 트레이스백입니다.

addUnexpectedSuccess(test)

테스트 케이스 test가 expectedFailure() 데코레이터로 표시되었지만, 성공한 경우 호출됩니다.

기본 구현은 테스트를 인스턴스의 unexpectedSuccesses 어트리뷰트에 추가합니다.

addSubTest(test, subtest, outcome)

부분 테스트가 완료되었을 때 호출됩니다. test는 테스트 메서드에 대응하는 테스트 케이스입니다. subtest는 부분 테스트를 설명하는 사용자 지정 TestCase 인스턴스입니다.

outcome이 None이면, 부분 테스트가 성공한 것입니다. 그렇지 않으면 예외와 함께 실패한 것인데 outcome은 sys.exc_info()가 반환한 형식의 튜플입니다: (type, value, traceback).

기본 구현은 결과가 성공인 경우 아무것도 하지 않고 부분 테스트의 실패를 일반적인 실패로 기록합니다.

Added in version 3.4.

addDuration(test, elapsed)

Called when the test case finishes. elapsed is the time represented in seconds, and it includes the execution of cleanup functions.

Added in version 3.12.

class unittest.TextTestResult(stream, descriptions, verbosity, *, durations=None)

A concrete implementation of TestResult used by the TextTestRunner. Subclasses should accept **kwargs to ensure compatibility as the interface changes.

Added in version 3.2.

버전 3.12에서 변경: Added the durations keyword parameter.

unittest.defaultTestLoader

공유 목적의 TestLoader 클래스의 인스턴스입니다. 만약 TestLoader를 사용자 정의할 필요가 없다면, 계속 새로운 인스턴스를 생성하는 것 대신 이 인스턴스를 사용할 수 있습니다.

class unittest.TextTestRunner(stream=None, descriptions=True, verbosity=1, failfast=False, buffer=False, resultclass=None, warnings=None, *, tb_locals=False, durations=None)

결과를 스트림으로 출력하는 기본 테스트 실행자 구현입니다. 만약 stream이 기본값인 None이라면, sys.stderr가 출력 스트림으로 사용됩니다. 이 클래스는 몇 가지 설정 가능한 매개변수를 가지고 있지만, 본질적으로 매우 간단합니다. 테스트 묶음을 실행하는 그래픽 애플리케이션은 대안 구현을 제공해야 합니다. 이러한 구현은 unittest에 기능이 추가될 때 실행자를 만드는 인터페이스가 변하기 때문에 **kwargs를 받아들여야 합니다.

By default this runner shows DeprecationWarning, PendingDeprecationWarning, ResourceWarning and ImportWarning even if they are ignored by default. This behavior can be overridden using Python’s -Wd or -Wa options (see Warning control) and leaving warnings to None.

버전 3.2에서 변경: Added the warnings parameter.

버전 3.2에서 변경: 임포트 시간이 아닌 인스턴스화 시간에 기본 스트림이 sys.stderr으로 설정됩니다.

버전 3.5에서 변경: Added the tb_locals parameter.

버전 3.12에서 변경: Added the durations parameter.

_makeResult()

이 메서드는 run()가 사용하는 TestResult 인스턴스를 반환합니다. 직접 호출하게 의도되지 않았지만, 사용자 정의 TestResult를 제공하기 위해 서브 클래스에서 오버라이드할 수 있습니다.

_makeResult()는 TextTestRunner 생성자에 resultclass 인자로 전달된 클래스나 콜러블을 인스턴스화합니다. 만약 resultclass가 제공되지 않았다면 기본값은 TextTestResult 입니다. 결과 클래스는 다음 인자와 함께 인스턴스화됩니다:

stream, descriptions, verbosity

run(test)

이 메서드는 TextTestRunner의 주된 공개 인터페이스입니다. 이 메서드는 TestSuite나 TestCase 인스턴스를 받습니다. TestResult는 _makeResult()를 호출하여 생성하고 테스트가 실행되며 결과가 stdout에 출력됩니다.

unittest.main(module='__main__', defaultTest=None, argv=None, testRunner=None, testLoader=unittest.defaultTestLoader, exit=True, verbosity=1, failfast=None, catchbreak=None, buffer=None, warnings=None)

module에서 테스트 모음을 로드하고 실행하는 명령행 프로그램입니다; 이것은 주로 편리하게 실행 가능한 테스트 모듈을 만들기 위한 것입니다. 이 함수의 가장 간단한 사용은 테스트 스크립트 마지막에 다음과 같은 줄을 포함하는 것입니다:

if __name__ == '__main__':
    unittest.main()

당신은 상세도 인자를 전달하여 좀 더 자세한 정보와 함께 테스트를 실행할 수 있습니다:

if __name__ == '__main__':
    unittest.main(verbosity=2)

defaultTest 인자는 argv로 테스트 이름이 지정되지 않은 경우 실행될 1개의 테스트 이름이거나 테스트 이름의 이터러블입니다. 만약 이 인자가 지정되지 않거나 None이면서 argv로 테스트 이름이 지정되지 않으면 module 안에서 찾은 모든 테스트가 실행됩니다.

argv 인자는 프로그램에 전달된 옵션 목록이 될 수 있습니다, 첫 번째 요소는 프로그램 이름입니다. 만약 이 인자가 지정되지 않거나 None이면, sys.argv 값이 사용됩니다.

The testRunner argument can either be a test runner class or an already created instance of it. By default main calls sys.exit() with an exit code indicating success (0) or failure (1) of the tests run. An exit code of 5 indicates that no tests were run or skipped.

testLoader 인자는 TestLoader 인스턴스이어야 하고 기본값은 defaultTestLoader 입니다.

main은 exit=False 인자를 전달하여 대화형 인터프리터에서 사용하는 것을 지원합니다. 이것은 sys.exit() 호출 없이 결과가 표준 출력에 표시됩니다:

>>> from unittest import main
>>> main(module='test_module', exit=False)

failfast, catchbreak, buffer 매개변수는 명령행 옵션의 같은 이름과 같은 효과를 가지고 있습니다.

warnings 인자는 테스트 실행 중에 사용되어야 할 경고 필터를 지정합니다. 만약 아무 값도 지정되지 않았다면, -W 옵션이 python으로 전달된 경우(경고 제어를 보십시오)에는 None으로 남아 있고, 그렇지 않은 경우에는 'default'로 설정됩니다.

Calling main returns an object with the result attribute that contains the result of the tests run as a unittest.TestResult.

버전 3.1에서 변경: exit 매개변수가 추가되었습니다.

버전 3.2에서 변경: verbosity, failfast, catchbreak, buffer, warnings 매개변수가 추가되었습니다.

버전 3.4에서 변경: defaultTest 매개변수가 테스트 이름의 이터러블도 받을 수 있게 바뀌었습니다.

load_tests 프로토콜

Added in version 3.2.

load_tests 라 불리는 함수를 구현함으로써 모듈이나 패키지는 일반 테스트 실행이나 테스트 탐색 중에 그것들로부터 테스트가 어떻게 로드될지를 사용자 정의할 수 있습니다.

만약 테스트 모듈이 load_tests를 정의했다면 그것은 다음 인자와 함께 TestLoader.loadTestsFromModule()의해 호출될 것입니다:

load_tests(loader, standard_tests, pattern)

여기서 pattern은 loadTestsFromModule에서 바로 전달된 것입니다. 기본값은 None입니다.

이것은 TestSuite를 반환해야 합니다.

loader는 로딩을 실행할 TestLoader 인스턴스입니다. standard_tests는 모듈에서 기본적으로 로드될 테스트입니다. 테스트 모듈이 테스트 기본 모음에서 오직 테스트를 추가하거나 빼기를 원하는 것은 흔한 일입니다. 세 번째 인자는 테스트 탐색의 일부로서 패키지를 로드할 때 사용됩니다.

특정 TestCase 클래스 모음에서 테스트를 로드하는 전형적인 load_tests 함수는 다음과 같습니다:

test_cases = (TestCase1, TestCase2, TestCase3)

def load_tests(loader, tests, pattern):
    suite = TestSuite()
    for test_class in test_cases:
        tests = loader.loadTestsFromTestCase(test_class)
        suite.addTests(tests)
    return suite

만약 탐색이 명령행 또는 TestLoader.discover()로부터, 패키지가 포함된 디렉터리에서 시작된다면, load_tests를 위해 패키지 __init__.py를 검사합니다. 만약 함수가 존재하지 않으면, 탐색은 그저 다른 디렉터리인 것처럼 패키지 안을 재귀 순회할 것입니다. 그렇지 않다면, 패키지의 테스트를 위한 탐색은 다음 인자와 함께 불리는 load_tests에게 맡겨질 것입니다:

load_tests(loader, standard_tests, pattern)

이것은 패키지의 모든 테스트에 해당하는 TestSuite를 반환해야 합니다. (standard_tests는 오직 __init__.py로부터 수집된 테스트만 포함할 것입니다.

패턴이 load_tests로 전달되기 때문에 패키지는 테스트 검색을 계속 진행(그리고 잠재적으로 수정)할 수 있습니다. 테스트 패키지를 위해서 ‘아무것도 하지 않는’ load_tests 함수는 다음과 같을 것입니다:

def load_tests(loader, standard_tests, pattern):
    # top level directory cached on loader instance
    this_dir = os.path.dirname(__file__)
    package_tests = loader.discover(start_dir=this_dir, pattern=pattern)
    standard_tests.addTests(package_tests)
    return standard_tests

버전 3.5에서 변경: 패키지 이름이 기본 패턴과 일치하는 것이 불가능하기 때문에 탐색이 더는 pattern 일치를 위해서 패키지 이름을 검사하지 않습니다.

클래스와 모듈 픽스쳐

클래스와 모듈 단계의 픽스쳐는 TestSuite에 구현되어 있습니다. 테스트 묶음이 새로운 클래스의 테스트를 만나면(만약 존재한다면) 이전 클래스의 tearDownClass() 가 호출되고, 이어 새로운 클래스의 setUpClass()가 호출됩니다.

마찬가지로 만약 테스트가 이전 테스트와 다른 모듈의 것이라면 이전 모듈의 tearDownModule이 실행되고, 이어 새로운 모듈의 setUpModule이 호출됩니다.

모든 테스트가 실행된 뒤에 마지막으로 tearDownClass와 tearDownModule이 실행됩니다.

공유하는 픽스쳐의 경우 테스트 병렬화와 같은 [잠재적인] 기능과 잘 동작하지 않고 이것은 테스트 분리를 망가트립니다. 이것을 주의 깊게 사용해야 합니다.

unittest의 테스트 로더에 의해 생성된 테스트들의 기본 정렬 순서는 같은 모듈과 클래스의 모든 테스트를 그룹화하는 것입니다. 이것은 setUpClass / setUpModule(등) 이 클래스와 모듈별로 정확하게 1번씩 호출되게 할 것입니다. 만약 당신이 무작위로 순서를 정하여, 그래서 다른 모듈과 클래스의 테스트가 서로 인접한다면, 이 공유 픽스처 함수는 1번의 테스트 실행에서 여러 번 호출될 수 있습니다.

공유 픽스처는 비표준 정렬 순서를 사용하는 테스트 묶음과 같이 작동하는 것을 의도하지 않습니다. 공유 픽스처를 지원하길 원치 않는 프레임워크를 위해서 BaseTestSuite가 여전히 존재합니다.

공유 픽스처 함수 중 1개에서 발생한 예외가 있다면, 테스트를 에러로 보고합니다. 해당 테스트 인스턴스가 없기 때문에 에러를 나타내기 위해 _ErrorHolder 객체(TestCase와 같은 인터페이스를 가진)가 생성됩니다. 당신이 그저 표준 unittest의 테스트 실행자를 사용한다면 이 세부 항목은 중요하지 않습니다, 그러나 당신이 프레임워크의 저자라면 이것은 관련이 있을 수 있습니다.

setUpClass 와 tearDownClass

이것들은 반드시 클래스 메서드로 구현되어야 합니다:

import unittest

class Test(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls._connection = createExpensiveConnectionObject()

    @classmethod
    def tearDownClass(cls):
        cls._connection.destroy()

만약 당신이 베이스 클래스의 setUpClass와 tearDownClass를 호출하고 싶다면 당신이 그것을 직접 호출해야만 합니다. TestCase의 구현은 비어있습니다.

만약 setUpClass 중에 예외가 발생한다면 클래스의 테스트는 실행되지 않고 tearDownClass 는 실행되지 않습니다. 건너뛴 클래스는 setUpClass 또는 tearDownClass가 실행되지 않을 것입니다. 만약 예외가 SkipTest 예외라면 클래스는 에러 대신 건너뛰어졌다고 보고될 것입니다.

setUpModule 과 tearDownModule

이것들은 함수로 구현되어야 합니다:

def setUpModule():
    createConnection()

def tearDownModule():
    closeConnection()

만약 setUpModule 중에 예외가 발생한다면 모듈의 테스트는 실행되지 않고 tearDownModule 는 실행되지 않습니다. 만약 예외가 SkipTest 예외라면 모듈은 에러 대신 건너뛰어졌다고 보고될 것입니다.

예외가 발생하는 경우에도 실행해야 하는 정리 코드를 추가하려면, addModuleCleanup을 사용하십시오:

unittest.addModuleCleanup(function, /, *args, **kwargs)

테스트 클래스 중에 사용된 자원을 정리하기 위해 tearDownModule() 이후에 불리는 함수를 추가합니다. 함수들은 추가된 순서의 반대 순서대로 불리게 됩니다(LIFO). 함수가 추가될 때 addModuleCleanup()에 같이 전달된 위치 인자나 키워드 인자와 함께 호출됩니다.

만약 setUpModule()이 실패한다면, 즉 tearDownModule()이 불리지 않더라도, 정리 함수들은 여전히 불리게 될 것입니다.

Added in version 3.8.

classmethod unittest.enterModuleContext(cm)

Enter the supplied context manager. If successful, also add its __exit__() method as a cleanup function by addModuleCleanup() and return the result of the __enter__() method.

Added in version 3.11.

unittest.doModuleCleanups()

이 함수는 tearDownModule() 이후나, setUpModule()이 예외를 발생시키면 setUpModule()이후에 조건 없이 호출됩니다.

It is responsible for calling all the cleanup functions added by addModuleCleanup(). If you need cleanup functions to be called prior to tearDownModule() then you can call doModuleCleanups() yourself.

doModuleCleanups()는 한 번에 하나씩 정리 함수 스택에서 메서드를 꺼내기 때문에 언제든지 호출될 수 있습니다.

Added in version 3.8.

시그널 처리하기

Added in version 3.2.

The -c/--catch command-line option to unittest, along with the catchbreak parameter to unittest.main(), provide more friendly handling of control-C during a test run. With catch break behavior enabled control-C will allow the currently running test to complete, and the test run will then end and report all the results so far. A second control-c will raise a KeyboardInterrupt in the usual way.

control-c 시그널 처리기는 자체 signal.SIGINT 처리기를 설치하는 코드 또는 테스트와의 호환성을 유지하려고 노력합니다. 만약 unittest 처리기가 불리지만 그것이 설치된 signal.SIGINT 처리기가 아니면, 즉 그것이 테스트 중에 시스템에 의해 대체되고 위임된다면, 그것은 기본 처리기를 호출합니다. 이것은 설치된 처리기를 대체하고 위임하는 코드에 의해 일반적으로 기대되는 동작입니다. unittest control-c 처리를 개별 테스트 별로 비활성화하고 싶을 때는 removeHandler() 데코레이터를 사용할 수 있습니다.

프레임워크 작성자가 테스트 프레임워크에서 control-c 처리 기능을 활성화하기 위해 몇 가지 유틸리티 함수가 있습니다.

unittest.installHandler()

control-c 처리기를 설치합니다. signal.SIGINT를 받았을 때(보통 사용자가 control-c를 눌렀을 때의 응답으로써) 모든 등록된 결과에 stop()이 호출됩니다.

unittest.registerResult(result)

control-c 처리를 위해서 TestResult 객체를 등록합니다. 결과 등록은 그것의 약한 참조를 저장합니다, 그래서 결과가 가비지 수거되는 것을 막지 않습니다.

만약 control-c 처리가 활성화되지 않았다면 TestResult 객체 등록은 부작용이 없습니다, 그래서 테스트 프레임워크는 처리가 가능한지 여부와 관계없이 자신이 만든 모든 결과를 무조건 등록할 수 있습니다.

unittest.removeResult(result)

등록한 결과를 제거합니다. 결과가 제거되고 나면 control-c에 대한 응답으로 결과 객체의 stop()을 더는 호출하지 않게 됩니다.

unittest.removeHandler(function=None)

인자 없이 호출된 경우 이 함수는 만약 control-c 처리기가 설치되었다면 그것을 제거합니다. 또한 이 함수는 테스트 실행 중에 임시로 처리기를 제거하기 위해 테스트 데코레이터로써 사용될 수도 있습니다:

@unittest.removeHandler
def test_signal_handling(self):
    ...

unittest.mock — mock object library

Added in version 3.3.

소스 코드: Lib/unittest/mock.py [https://github.com/python/cpython/tree/main/Lib/unittest/mock.py]

unittest.mock은 파이썬에서 테스트하기 위한 라이브러리입니다. 테스트 대상 시스템의 일부를 모의 객체로 교체하고 그들이 사용된 방식에 대해 어서션(assertion)을 할 수 있습니다.

unittest.mock은 핵심 Mock 클래스를 제공하여 테스트 스위트 전체에 걸쳐 많은 스텁을 만들 필요가 없도록 합니다. 작업을 수행한 후, 사용된 메서드 / 어트리뷰트와 호출에 제공된 인자에 대한 어서션을 할 수 있습니다. 일반적인 방법으로 반환 값을 지정하고 필요한 어트리뷰트를 설정할 수도 있습니다.

또한, mock은 테스트 스코프 내에서 모듈과 클래스 수준 어트리뷰트의 패치를 처리하는 patch() 데코레이터를 고유한 객체 생성을 위한 sentinel과 함께 제공합니다. Mock, MagicMock 및 patch() 사용 방법에 대한 몇 가지 예는 간략 지침을 참조하십시오.

Mock은 unittest와 함께 사용하도록 설계되었고 많은 모킹(mocking) 프레임워크에서 사용하는 ‘기록(record) -> 재생(replay)’ 대신 ‘액션(action) -> 어서션(assertion)’ 패턴을 기반으로 합니다.

There is a backport of unittest.mock for earlier versions of Python, available as mock [https://pypi.org/project/mock/] on PyPI.

간략 지침

Mock과 MagicMock 객체는 그것들을 액세스함에 따라 모든 어트리뷰트와 메서드를 작성하고 사용 방식에 대한 세부 사항을 저장합니다. 반환 값을 지정하거나 사용 가능한 어트리뷰트를 제한하도록 구성한 다음, 사용된 방식에 대한 어서션을 만들 수 있습니다:

>>> from unittest.mock import MagicMock
>>> thing = ProductionClass()
>>> thing.method = MagicMock(return_value=3)
>>> thing.method(3, 4, 5, key='value')
3
>>> thing.method.assert_called_with(3, 4, 5, key='value')

side_effect allows you to perform side effects, including raising an exception when a mock is called:

>>> from unittest.mock import Mock
>>> mock = Mock(side_effect=KeyError('foo'))
>>> mock()
Traceback (most recent call last):
 ...
KeyError: 'foo'

>>> values = {'a': 1, 'b': 2, 'c': 3}
>>> def side_effect(arg):
...     return values[arg]
...
>>> mock.side_effect = side_effect
>>> mock('a'), mock('b'), mock('c')
(1, 2, 3)
>>> mock.side_effect = [5, 4, 3, 2, 1]
>>> mock(), mock(), mock()
(5, 4, 3)

Mock은 여러 가지 방법으로 구성하고 동작을 제어 할 수 있습니다. 예를 들어 spec 인자는 다른 객체에서 사양을 가져오도록 모의 객체를 구성합니다. spec에 존재하지 않는 모의 객체의 어트리뷰트나 메서드에 액세스하려고 시도하면 AttributeError로 실패합니다.

patch() 데코레이터 / 컨텍스트 관리자는 테스트 대상 모듈에서 클래스나 객체를 쉽게 모킹할 수 있도록 합니다. 지정한 객체는 테스트 중에 모의 객체(또는 다른 객체)로 치환되고 테스트가 끝나면 복원됩니다:

>>> from unittest.mock import patch
>>> @patch('module.ClassName2')
... @patch('module.ClassName1')
... def test(MockClass1, MockClass2):
...     module.ClassName1()
...     module.ClassName2()
...     assert MockClass1 is module.ClassName1
...     assert MockClass2 is module.ClassName2
...     assert MockClass1.called
...     assert MockClass2.called
...
>>> test()

참고

patch 데코레이터를 중첩할 때 모의 객체는 적용한 순서와 같은 순서로 데코레이트 되는 함수로 전달됩니다 (데코레이터가 적용되는 일반적인 파이썬 순서). 이것은 아래에서 위로 감을 뜻하므로, 위의 예에서 module.ClassName1에 대한 모의 객체가 먼저 전달됩니다.

patch()를 사용할 때 조회되는 이름 공간에서 객체를 패치하는 것이 중요합니다. 이것은 일반적으로 간단하지만, 간략 지침은 패치할 곳을 읽으십시오.

데코레이터 patch()는 with 문에서 컨텍스트 관리자로 사용할 수도 있습니다:

>>> with patch.object(ProductionClass, 'method', return_value=None) as mock_method:
...     thing = ProductionClass()
...     thing.method(1, 2, 3)
...
>>> mock_method.assert_called_once_with(1, 2, 3)

스코프 도중 딕셔너리에 값을 설정하고 테스트가 종료될 때 딕셔너리를 원래 상태로 복원하기 위한 patch.dict()도 있습니다:

>>> foo = {'key': 'value'}
>>> original = foo.copy()
>>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
...     assert foo == {'newkey': 'newvalue'}
...
>>> assert foo == original

Mock은 파이썬 매직 메서드의 모킹을 지원합니다. 매직 메서드를 사용하는 가장 쉬운 방법은 MagicMock 클래스를 사용하는 것입니다. 다음과 같은 것을 할 수 있도록 합니다:

>>> mock = MagicMock()
>>> mock.__str__.return_value = 'foobarbaz'
>>> str(mock)
'foobarbaz'
>>> mock.__str__.assert_called_with()

Mock을 사용하면 함수(또는 다른 Mock 인스턴스)를 매직 메서드에 대입할 수 있고 적절하게 호출될 것입니다. MagicMock 클래스는 모든 매직 메서드(아마도, 모든 유용한 메서드)가 미리 만들어져 있는 Mock 변형일 뿐입니다.

다음은 평범한 Mock 클래스로 매직 메서드를 사용하는 예입니다:

>>> mock = Mock()
>>> mock.__str__ = Mock(return_value='wheeeeee')
>>> str(mock)
'wheeeeee'

테스트의 모의 객체가 대체하는 객체와 같은 api를 갖도록, 자동 사양를 사용할 수 있습니다. 자동 사양은 패치 할 autospec 인자를 patch에 전달하거나 create_autospec() 함수를 통해 수행할 수 있습니다. 자동 사양은 대체하는 객체와 같은 어트리뷰트와 메서드를 갖는 모의 객체를 만들고, 모든 함수와 (생성자를 포함한) 메서드는 실제 객체와 같은 호출 서명을 갖습니다.

이것은 모의 객체가 잘못 사용될 경우 프로덕션 코드와 같은 방식으로 실패하도록 합니다:

>>> from unittest.mock import create_autospec
>>> def function(a, b, c):
...     pass
...
>>> mock_function = create_autospec(function, return_value='fishy')
>>> mock_function(1, 2, 3)
'fishy'
>>> mock_function.assert_called_once_with(1, 2, 3)
>>> mock_function('wrong arguments')
Traceback (most recent call last):
 ...
TypeError: missing a required argument: 'b'

create_autospec()이 클래스에 사용되면 __init__ 메서드의 서명을 복사하고, 콜러블 객체에 사용되면 __call__ 메서드의 서명을 복사합니다.

Mock 클래스

Mock은 코드 전체에서 스텁과 테스트 이중화의 사용을 대체하기 위한 유연한 모의 객체입니다. 모의 객체는 콜러블이고 어트리뷰트에 액세스할 때 새 모의 객체로 어트리뷰트를 만듭니다 [1]. 같은 어트리뷰트에 액세스하면 항상 같은 모의 객체를 반환합니다. 모의 객체는 사용 방법을 기록하여, 코드가 모의 객체에 대해 수행한 작업에 대한 어서션을 만들 수 있도록 합니다.

MagicMock은 Mock의 서브 클래스이며, 모든 매직 메서드가 미리 만들어져 사용할 준비가 되어있습니다. 콜러블이 아닌 변형도 있어서, 콜러블이 아닌 객체를 모킹할 때 유용합니다: NonCallableMock과 NonCallableMagicMock

patch() 데코레이터를 사용하면 특정 모듈의 클래스를 Mock 객체로 쉽게 대체 할 수 있습니다. 기본적으로 patch()는 MagicMock을 생성합니다. patch()에 new_callable 인자를 사용하여 대체 Mock 클래스를 지정할 수 있습니다.

class unittest.mock.Mock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, **kwargs)

새로운 Mock 객체를 만듭니다. Mock은 Mock 객체의 동작을 지정하는 몇 가지 선택적 인자를 취합니다:

spec: 문자열 리스트이거나 모의 객체의 사양으로 작동하는 기존 객체 (클래스나 인스턴스)일 수 있습니다. 객체를 전달하면 객체에 dir을 호출하여 문자열 리스트가 형성됩니다 (지원되지 않는 매직 어트리뷰트와 메서드는 제외합니다). 이 리스트에 없는 어트리뷰트에 액세스하면 AttributeError가 발생합니다.

If spec is an object (rather than a list of strings) then __class__ returns the class of the spec object. This allows mocks to pass isinstance() tests.

spec_set: spec의 더 엄격한 변형. 사용되면, spec_set으로 전달된 객체에 없는 모의 객체의 어트리뷰트를 설정하거나 얻으려고 시도하면 AttributeError가 발생합니다.

side_effect: Mock이 호출될 때마다 호출되는 함수. side_effect 어트리뷰트를 참조하십시오. 예외를 발생시키거나 반환 값을 동적으로 변경하는 데 유용합니다. 함수는 모의 객체와 같은 인자로 호출되며, DEFAULT를 반환하지 않는 한, 이 함수의 반환 값이 반환 값으로 사용됩니다.

또는 side_effect는 예외 클래스나 인스턴스일 수 있습니다. 이 경우 모의 객체가 호출될 때 그 예외가 발생합니다.

side_effect가 이터러블이면 모의 객체에 대한 각 호출은 이터러블의 다음 값을 반환합니다.

side_effect는 None으로 설정하여 지울 수 있습니다.

return_value: 모의 객체가 호출될 때 반환되는 값. 기본적으로 이것은 새로운 Mock입니다 (처음 액세스할 때 만들어집니다). return_value 어트리뷰트를 참조하십시오.

unsafe: By default, accessing any attribute whose name starts with assert, assret, asert, aseert or assrt will raise an AttributeError. Passing unsafe=True will allow access to these attributes.

Added in version 3.5.

wraps: 모의 객체가 감쌀 항목. wraps가 None이 아니면 Mock을 호출할 때 래핑 된 객체로 호출이 전달됩니다 (실제 결과를 반환합니다). 모의 객체에 대한 어트리뷰트 액세스는 래핑 된 객체의 해당 어트리뷰트를 래핑하는 Mock 객체를 반환합니다 (따라서 존재하지 않는 어트리뷰트에 액세스하려고 시도하면 AttributeError가 발생합니다).

모의 객체에 명시적으로 return_value가 설정되면 호출은 래핑 된 객체로 전달되지 않고 대신 return_value가 반환됩니다.

name: 모의 객체에 이름이 있으면 모의 객체의 repr에 사용됩니다. 디버깅에 유용할 수 있습니다. 이름은 자식 모의 객체로 전파됩니다.

임의의 키워드 인자로 모의 객체를 호출할 수도 있습니다. 이것들은 모의 객체가 만들어진 후에 어트리뷰트를 설정하는 데 사용됩니다. 자세한 내용은 configure_mock() 메서드를 참조하십시오.

assert_called()

모의 객체가 적어도 한 번 호출되었다고 어서트 합니다.

>>> mock = Mock()
>>> mock.method()
<Mock name='mock.method()' id='...'>
>>> mock.method.assert_called()

Added in version 3.6.

assert_called_once()

모의 객체가 정확히 한 번 호출되었다고 어서트 합니다.

>>> mock = Mock()
>>> mock.method()
<Mock name='mock.method()' id='...'>
>>> mock.method.assert_called_once()
>>> mock.method()
<Mock name='mock.method()' id='...'>
>>> mock.method.assert_called_once()
Traceback (most recent call last):
...
AssertionError: Expected 'method' to have been called once. Called 2 times.
Calls: [call(), call()].

Added in version 3.6.

assert_called_with(*args, **kwargs)

이 메서드는 마지막 호출이 특정 방식으로 이루어졌음을 어서트하는 편리한 방법입니다:

>>> mock = Mock()
>>> mock.method(1, 2, 3, test='wow')
<Mock name='mock.method()' id='...'>
>>> mock.method.assert_called_with(1, 2, 3, test='wow')

assert_called_once_with(*args, **kwargs)

Assert that the mock was called exactly once and that call was with the specified arguments.

>>> mock = Mock(return_value=None)
>>> mock('foo', bar='baz')
>>> mock.assert_called_once_with('foo', bar='baz')
>>> mock('other', bar='values')
>>> mock.assert_called_once_with('other', bar='values')
Traceback (most recent call last):
  ...
AssertionError: Expected 'mock' to be called once. Called 2 times.
Calls: [call('foo', bar='baz'), call('other', bar='values')].

assert_any_call(*args, **kwargs)

지정된 인자로 모의 객체가 호출되었다고 어서트 합니다.

호출이 가장 최근 호출일 때만 통과하는 assert_called_with()와 assert_called_once_with(), 그리고 assert_called_once_with()의 경우 유일한 호출이어야 하는 것과 달리 모의 객체가 호출된 적이 있으면 어서트가 통과합니다.

>>> mock = Mock(return_value=None)
>>> mock(1, 2, arg='thing')
>>> mock('some', 'thing', 'else')
>>> mock.assert_any_call(1, 2, arg='thing')

assert_has_calls(calls, any_order=False)

지정된 호출로 모의 객체가 호출되었다고 어서트 합니다. calls에 대해 mock_calls 리스트를 검사합니다.

any_order가 거짓이면 호출은 순차적이어야 합니다. 지정된 호출 전후에 추가 호출이 있을 수 있습니다.

any_order가 참이면 호출 순서는 상관없지만, 모두 mock_calls에 나타나야 합니다.

>>> mock = Mock(return_value=None)
>>> mock(1)
>>> mock(2)
>>> mock(3)
>>> mock(4)
>>> calls = [call(2), call(3)]
>>> mock.assert_has_calls(calls)
>>> calls = [call(4), call(2), call(3)]
>>> mock.assert_has_calls(calls, any_order=True)

assert_not_called()

모의 객체가 호출되지 않았다고 어서트 합니다.

>>> m = Mock()
>>> m.hello.assert_not_called()
>>> obj = m.hello()
>>> m.hello.assert_not_called()
Traceback (most recent call last):
  ...
AssertionError: Expected 'hello' to not have been called. Called 1 times.
Calls: [call()].

Added in version 3.5.

reset_mock(*, return_value=False, side_effect=False)

reset_mock 메서드는 모의 객체의 모든 호출 어트리뷰트를 재설정합니다:

>>> mock = Mock(return_value=None)
>>> mock('hello')
>>> mock.called
True
>>> mock.reset_mock()
>>> mock.called
False

This can be useful where you want to make a series of assertions that reuse the same object.

return_value parameter when set to True resets return_value:

>>> mock = Mock(return_value=5)
>>> mock('hello')
5
>>> mock.reset_mock(return_value=True)
>>> mock('hello')
<Mock name='mock()' id='...'>

side_effect parameter when set to True resets side_effect:

>>> mock = Mock(side_effect=ValueError)
>>> mock('hello')
Traceback (most recent call last):
  ...
ValueError
>>> mock.reset_mock(side_effect=True)
>>> mock('hello')
<Mock name='mock()' id='...'>

Note that reset_mock() doesn’t clear the return_value, side_effect or any child attributes you have set using normal assignment by default.

Child mocks are reset as well.

버전 3.6에서 변경: Added two keyword-only arguments to the reset_mock function.

mock_add_spec(spec, spec_set=False)

모의 객체에 사양을 추가합니다. spec은 객체이거나 문자열 리스트일 수 있습니다. spec의 어트리뷰트 만 모의 객체에서 어트리뷰트로 꺼낼 수 있습니다.

spec_set이 참이면 스펙에 있는 어트리뷰트 만 설정할 수 있습니다.

attach_mock(mock, attribute)

이름과 부모를 치환해서, 이것의 어트리뷰트(attribute)로 모의 객체(mock)를 연결합니다. 연결된 모의 객체에 대한 호출은 이것의 method_calls와 mock_calls 어트리뷰트에 기록됩니다.

configure_mock(**kwargs)

키워드 인자를 통해 모의 객체의 어트리뷰트를 설정합니다.

표준 점 표기법과 메서드 호출에서 딕셔너리 언 패킹을 사용해서 자식 모의 객체에 어트리뷰트와 반환 값 및 부작용을 설정할 수 있습니다:

>>> mock = Mock()
>>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
>>> mock.configure_mock(**attrs)
>>> mock.method()
3
>>> mock.other()
Traceback (most recent call last):
  ...
KeyError

모의 객체에 대한 생성자 호출에서 같은 것을 할 수 있습니다:

>>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
>>> mock = Mock(some_attribute='eggs', **attrs)
>>> mock.some_attribute
'eggs'
>>> mock.method()
3
>>> mock.other()
Traceback (most recent call last):
  ...
KeyError

configure_mock()은 모의 객체를 만든 후에 구성을 더 쉽게 할 수 있도록 하기 위해 존재합니다.

__dir__()

Mock 객체는 dir(some_mock)의 결과를 유용한 결과로 제한합니다. spec이 있는 모의 객체에서 이것은 모의 객체에 허용되는 모든 어트리뷰트를 포함합니다.

이 필터링이 하는 일과 해제 방법에 대해서는 FILTER_DIR을 참조하십시오.

_get_child_mock(**kw)

어트리뷰트와 반환 값에 대한 자식 모의 객체를 만듭니다. 기본적으로 자식 모의 객체는 부모와 같은 형입니다. Mock의 서브 클래스는 자식 모의 객체가 만들어지는 방법을 사용자 정의하기 위해 이를 재정의할 수 있습니다.

콜러블이 아닌 모의 객체의 경우 (사용자 정의 서브 클래스 대신) 콜러블 변형이 사용됩니다.

called

모의 객체가 호출되었는지를 나타내는 불리언:

>>> mock = Mock(return_value=None)
>>> mock.called
False
>>> mock()
>>> mock.called
True

call_count

모의 객체가 몇 번이나 호출되었는지를 알려주는 정수:

>>> mock = Mock(return_value=None)
>>> mock.call_count
0
>>> mock()
>>> mock()
>>> mock.call_count
2

return_value

모의 객체를 호출할 때 반환되는 값을 구성하려면 이것을 설정하십시오:

>>> mock = Mock()
>>> mock.return_value = 'fish'
>>> mock()
'fish'

기본 반환 값은 모의 객체이며 일반적인 방식으로 구성할 수 있습니다:

>>> mock = Mock()
>>> mock.return_value.attribute = sentinel.Attribute
>>> mock.return_value()
<Mock name='mock()()' id='...'>
>>> mock.return_value.assert_called_with()

생성자에서 return_value를 설정할 수도 있습니다:

>>> mock = Mock(return_value=3)
>>> mock.return_value
3
>>> mock()
3

side_effect

이것은 모의 객체가 호출될 때 호출되는 함수, 이터러블 또는 발생시킬 예외(클래스나 인스턴스)일 수 있습니다.

함수를 전달하면 모의 객체와 같은 인자로 호출되며 함수가 DEFAULT 싱글톤을 반환하지 않는 한 모의 객체에 대한 호출은 함수가 반환하는 것을 반환합니다. 함수가 DEFAULT를 반환하면 모의 객체는 (return_value에서) 정상값을 반환합니다.

이터러블을 전달하면, 모든 호출에서 값을 산출해야 하는 이터레이터를 얻는 데 사용됩니다. 이 값은 발생시킬 예외 인스턴스나 모의 객체 호출에서 반환될 값일 수 있습니다 (DEFAULT 처리는 함수 경우와 같습니다).

(API의 예외 처리를 테스트하기 위해) 예외를 발생시키는 모의 객체 예:

>>> mock = Mock()
>>> mock.side_effect = Exception('Boom!')
>>> mock()
Traceback (most recent call last):
  ...
Exception: Boom!

side_effect를 사용하여 일련의 값을 반환하기:

>>> mock = Mock()
>>> mock.side_effect = [3, 2, 1]
>>> mock(), mock(), mock()
(3, 2, 1)

콜러블 사용하기:

>>> mock = Mock(return_value=3)
>>> def side_effect(*args, **kwargs):
...     return DEFAULT
...
>>> mock.side_effect = side_effect
>>> mock()
3

생성자에서 side_effect를 설정할 수 있습니다. 다음은 모의 객체가 호출된 값에 1을 더해서 반환하는 예입니다:

>>> side_effect = lambda value: value + 1
>>> mock = Mock(side_effect=side_effect)
>>> mock(3)
4
>>> mock(-8)
-7

side_effect를 None으로 설정하면 지워집니다:

>>> m = Mock(side_effect=KeyError, return_value=3)
>>> m()
Traceback (most recent call last):
 ...
KeyError
>>> m.side_effect = None
>>> m()
3

call_args

이것은 None(모의 객체가 호출되지 않았을 때)이거나 모의 객체가 마지막으로 호출된 인자입니다. 이것은 튜플 형태입니다: args 프로퍼티를 통해 액세스 할 수도 있는 첫 번째 멤버는 모의 객체를 호출한 순서 있는 인자(또는 빈 튜플)이며 kwargs 프로퍼티를 통해 액세스 할 수도 있는 두 번째 멤버는 모든 키워드 인자(또는 빈 딕셔너리)입니다.

>>> mock = Mock(return_value=None)
>>> print(mock.call_args)
None
>>> mock()
>>> mock.call_args
call()
>>> mock.call_args == ()
True
>>> mock(3, 4)
>>> mock.call_args
call(3, 4)
>>> mock.call_args == ((3, 4),)
True
>>> mock.call_args.args
(3, 4)
>>> mock.call_args.kwargs
{}
>>> mock(3, 4, 5, key='fish', next='w00t!')
>>> mock.call_args
call(3, 4, 5, key='fish', next='w00t!')
>>> mock.call_args.args
(3, 4, 5)
>>> mock.call_args.kwargs
{'key': 'fish', 'next': 'w00t!'}

call_args_list, method_calls 및 mock_calls 리스트의 멤버와 함께 call_args는 call 객체입니다. 이들은 튜플이므로, 개별 인자를 얻고 더 복잡한 어서션을 하기 위해 언팩할 수 있습니다. call 튜플을 참조하십시오.

버전 3.8에서 변경: args와 kwargs 프로퍼티를 추가했습니다.

call_args_list

이것은 모의 객체에 대한 모든 호출을 순서대로 나열한 리스트입니다 (따라서 리스트의 길이는 호출된 횟수입니다). 호출이 있기 전에는 빈 리스트입니다. call 객체는 call_args_list와 비교할 호출 리스트를 편리하게 구성하는 데 사용할 수 있습니다.

>>> mock = Mock(return_value=None)
>>> mock()
>>> mock(3, 4)
>>> mock(key='fish', next='w00t!')
>>> mock.call_args_list
[call(), call(3, 4), call(key='fish', next='w00t!')]
>>> expected = [(), ((3, 4),), ({'key': 'fish', 'next': 'w00t!'},)]
>>> mock.call_args_list == expected
True

call_args_list의 멤버는 call 객체입니다. 이들은 개별 인자를 얻기 위해 튜플로서 언팩될 수 있습니다. call 튜플을 참조하십시오.

method_calls

자신에 대한 호출 추적뿐만 아니라, 모의 객체는 메서드와 어트리뷰트, 그리고 그들의 메서드와 어트리뷰트에 대한 호출도 추적합니다:

>>> mock = Mock()
>>> mock.method()
<Mock name='mock.method()' id='...'>
>>> mock.property.method.attribute()
<Mock name='mock.property.method.attribute()' id='...'>
>>> mock.method_calls
[call.method(), call.property.method.attribute()]

method_calls의 멤버는 call 객체입니다. 이들은 개별 인자를 얻기 위해 튜플로서 언팩될 수 있습니다. call 튜플을 참조하십시오.

mock_calls

mock_calls는 모의 객체, 그것의 메서드, 매직 메서드 및 반환 값 모의 객체에 대한 모든 호출을 기록합니다.

>>> mock = MagicMock()
>>> result = mock(1, 2, 3)
>>> mock.first(a=3)
<MagicMock name='mock.first()' id='...'>
>>> mock.second()
<MagicMock name='mock.second()' id='...'>
>>> int(mock)
1
>>> result(1)
<MagicMock name='mock()()' id='...'>
>>> expected = [call(1, 2, 3), call.first(a=3), call.second(),
... call.__int__(), call()(1)]
>>> mock.mock_calls == expected
True

mock_calls의 멤버는 call 객체입니다. 이들은 개별 인자를 얻기 위해 튜플로서 언팩될 수 있습니다. call 튜플을 참조하십시오.

참고

mock_calls가 기록되는 방식은 중첩된 호출이 수행될 때 상위 호출의 매개 변수가 기록되지 않아서 항상 같다고 비교됨을 뜻합니다.:

>>> mock = MagicMock()
>>> mock.top(a=3).bottom()
<MagicMock name='mock.top().bottom()' id='...'>
>>> mock.mock_calls
[call.top(a=3), call.top().bottom()]
>>> mock.mock_calls[-1] == call.top(a=-1).bottom()
True

__class__

Normally the __class__ attribute of an object will return its type. For a mock object with a spec, __class__ returns the spec class instead. This allows mock objects to pass isinstance() tests for the object they are replacing / masquerading as:

>>> mock = Mock(spec=3)
>>> isinstance(mock, int)
True

__class__ is assignable to, this allows a mock to pass an isinstance() check without forcing you to use a spec:

>>> mock = Mock()
>>> mock.__class__ = dict
>>> isinstance(mock, dict)
True

class unittest.mock.NonCallableMock(spec=None, wraps=None, name=None, spec_set=None, **kwargs)

콜러블이 아닌 Mock 버전. 생성자 매개 변수는 Mock과 같은 의미를 가지며, 콜러블이 아닌 모의 객체에서 의미가 없는 return_value와 side_effect는 예외입니다.

Mock objects that use a class or an instance as a spec or spec_set are able to pass isinstance() tests:

>>> mock = Mock(spec=SomeClass)
>>> isinstance(mock, SomeClass)
True
>>> mock = Mock(spec_set=SomeClass())
>>> isinstance(mock, SomeClass)
True

Mock 클래스는 매직 메서드 모킹을 지원합니다. 자세한 내용은 매직 메서드를 참조하십시오.

모의 객체 클래스와 patch() 데코레이터는 모두 구성을 위해 임의의 키워드 인자를 취합니다. patch() 데코레이터의 경우 키워드는 만들어지는 모의 객체의 생성자로 전달됩니다. 키워드 인자는 모의 객체의 어트리뷰트를 구성하기 위한 것입니다.:

>>> m = MagicMock(attribute=3, other='fish')
>>> m.attribute
3
>>> m.other
'fish'

자식 모의 객체의 반환 값과 부작용은 점 표기법을 사용하여 같은 방식으로 설정할 수 있습니다. 호출에서 점으로 구분된 이름을 직접 사용할 수 없어서 딕셔너리를 만들고 **를 사용하여 언팩해야 합니다:

>>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
>>> mock = Mock(some_attribute='eggs', **attrs)
>>> mock.some_attribute
'eggs'
>>> mock.method()
3
>>> mock.other()
Traceback (most recent call last):
  ...
KeyError

spec(또는 spec_set)으로 만들어진 콜러블 모의 객체는 호출을 모의 객체와 일치시킬 때 사양 객체의 서명을 검사합니다. 따라서, 위치나 이름으로 전달되었는지와 관계없이 실제 호출의 인자와 일치할 수 있습니다:

>>> def f(a, b, c): pass
...
>>> mock = Mock(spec=f)
>>> mock(1, 2, c=3)
<Mock name='mock()' id='140161580456576'>
>>> mock.assert_called_with(1, 2, 3)
>>> mock.assert_called_with(a=1, b=2, c=3)

이것은 assert_called_with(), assert_called_once_with(), assert_has_calls() 및 assert_any_call()에 적용됩니다. 자동 사양할 때, 모의 객체의 메서드 호출에도 적용됩니다.

버전 3.4에서 변경: spec 되거나 자동 사양된 모의 객체에 대한 서명 검사를 추가했습니다.

class unittest.mock.PropertyMock(*args, **kwargs)

A mock intended to be used as a property, or other descriptor, on a class. PropertyMock provides __get__() and __set__() methods so you can specify a return value when it is fetched.

객체에서 PropertyMock 인스턴스를 가져오면 인자 없이 모의 객체를 호출합니다. 설정하면 설정되는 값으로 모의 객체를 호출합니다.

>>> class Foo:
...     @property
...     def foo(self):
...         return 'something'
...     @foo.setter
...     def foo(self, value):
...         pass
...
>>> with patch('__main__.Foo.foo', new_callable=PropertyMock) as mock_foo:
...     mock_foo.return_value = 'mockity-mock'
...     this_foo = Foo()
...     print(this_foo.foo)
...     this_foo.foo = 6
...
mockity-mock
>>> mock_foo.mock_calls
[call(), call(6)]

모의 객체 어트리뷰트가 저장되는 방식으로 인해 PropertyMock을 모의 객체에 직접 연결할 수 없습니다. 대신 모의 객체의 형 객체에 연결할 수 있습니다:

>>> m = MagicMock()
>>> p = PropertyMock(return_value=3)
>>> type(m).foo = p
>>> m.foo
3
>>> p.assert_called_once_with()

조심

If an AttributeError is raised by PropertyMock, it will be interpreted as a missing descriptor and __getattr__() will be called on the parent mock:

>>> m = MagicMock()
>>> no_attribute = PropertyMock(side_effect=AttributeError)
>>> type(m).my_property = no_attribute
>>> m.my_property
<MagicMock name='mock.my_property' id='140165240345424'>

See __getattr__() for details.

class unittest.mock.AsyncMock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, **kwargs)

MagicMock의 비동기 버전. AsyncMock 객체는 객체가 비동기 함수로 인식되도록 동작하고, 호출 결과는 어웨이터블 입니다.

>>> mock = AsyncMock()
>>> inspect.iscoroutinefunction(mock)
True
>>> inspect.isawaitable(mock())
True

mock()의 결과는 어웨이트 한 후 side_effect나 return_value를 제공하는 비동기 함수입니다:

side_effect가 함수이면, 비동기 함수는 해당 함수의 결과를 반환합니다,

side_effect가 예외이면, 비동기 함수는 예외를 발생시킵니다,

side_effect가 이터러블이면, 비동기 함수는 이터러블의 다음 값을 반환하지만, 결과 시퀀스가 소진되면 StopAsyncIteration이 즉시 발생합니다,

side_effect가 정의되지 않으면, 비동기 함수는 return_value에 의해 정의된 값을 반환하므로, 기본적으로 비동기 함수는 새 AsyncMock 객체를 반환합니다.

Mock이나 MagicMock의 spec을 비동기 함수로 설정하면 호출 후에 코루틴 객체가 반환됩니다.

>>> async def async_func(): pass
...
>>> mock = MagicMock(async_func)
>>> mock
<MagicMock spec='function' id='...'>
>>> mock()
<coroutine object AsyncMockMixin._mock_call at ...>

Mock, MagicMock 또는 AsyncMock의 spec을 비동기와 동기 함수가 있는 클래스로 설정하면 동기 함수를 자동으로 감지하고 그들을 MagicMock(부모 모의 객체가 AsyncMock이나 MagicMock일 때)이나 Mock(부모 모의 객체가 Mock일 때)으로 설정합니다. 모든 비동기 함수는 AsyncMock이 됩니다.

>>> class ExampleClass:
...     def sync_foo():
...         pass
...     async def async_foo():
...         pass
...
>>> a_mock = AsyncMock(ExampleClass)
>>> a_mock.sync_foo
<MagicMock name='mock.sync_foo' id='...'>
>>> a_mock.async_foo
<AsyncMock name='mock.async_foo' id='...'>
>>> mock = Mock(ExampleClass)
>>> mock.sync_foo
<Mock name='mock.sync_foo' id='...'>
>>> mock.async_foo
<AsyncMock name='mock.async_foo' id='...'>

Added in version 3.8.

assert_awaited()

모의 객체가 적어도 한 번 어웨이트 되었다고 어서트 합니다. 이것은 호출된 객체와 별개임에 유의하십시오, await 키워드를 반드시 사용해야 합니다:

>>> mock = AsyncMock()
>>> async def main(coroutine_mock):
...     await coroutine_mock
...
>>> coroutine_mock = mock()
>>> mock.called
True
>>> mock.assert_awaited()
Traceback (most recent call last):
...
AssertionError: Expected mock to have been awaited.
>>> asyncio.run(main(coroutine_mock))
>>> mock.assert_awaited()

assert_awaited_once()

모의 객체가 정확히 한 번 어웨이트 되었다고 어서트 합니다.

>>> mock = AsyncMock()
>>> async def main():
...     await mock()
...
>>> asyncio.run(main())
>>> mock.assert_awaited_once()
>>> asyncio.run(main())
>>> mock.assert_awaited_once()
Traceback (most recent call last):
...
AssertionError: Expected mock to have been awaited once. Awaited 2 times.

assert_awaited_with(*args, **kwargs)

마지막 어웨이트가 지정된 인자로 이루어졌다고 어서트 합니다.

>>> mock = AsyncMock()
>>> async def main(*args, **kwargs):
...     await mock(*args, **kwargs)
...
>>> asyncio.run(main('foo', bar='bar'))
>>> mock.assert_awaited_with('foo', bar='bar')
>>> mock.assert_awaited_with('other')
Traceback (most recent call last):
...
AssertionError: expected await not found.
Expected: mock('other')
Actual: mock('foo', bar='bar')

assert_awaited_once_with(*args, **kwargs)

모의 객체가 정확히 한 번, 지정된 인자로 어웨이트 되었다고 어서트 합니다.

>>> mock = AsyncMock()
>>> async def main(*args, **kwargs):
...     await mock(*args, **kwargs)
...
>>> asyncio.run(main('foo', bar='bar'))
>>> mock.assert_awaited_once_with('foo', bar='bar')
>>> asyncio.run(main('foo', bar='bar'))
>>> mock.assert_awaited_once_with('foo', bar='bar')
Traceback (most recent call last):
...
AssertionError: Expected mock to have been awaited once. Awaited 2 times.

assert_any_await(*args, **kwargs)

지정된 인자로 모의 객체가 어웨이트된 적이 있다고 어서트 합니다.

>>> mock = AsyncMock()
>>> async def main(*args, **kwargs):
...     await mock(*args, **kwargs)
...
>>> asyncio.run(main('foo', bar='bar'))
>>> asyncio.run(main('hello'))
>>> mock.assert_any_await('foo', bar='bar')
>>> mock.assert_any_await('other')
Traceback (most recent call last):
...
AssertionError: mock('other') await not found

assert_has_awaits(calls, any_order=False)

지정된 호출로 모의 객체가 어웨이트 되었다고 어서트 합니다. 어웨이트에 대해 await_args_list 리스트가 검사됩니다.

any_order가 거짓이면 어웨이트는 순차적이어야 합니다. 지정된 어웨이트 전이나 후에 추가 호출이 있을 수 있습니다.

any_order가 참이면 어웨이트 순서와 관계없이 모두 await_args_list에 나타나야 합니다.

>>> mock = AsyncMock()
>>> async def main(*args, **kwargs):
...     await mock(*args, **kwargs)
...
>>> calls = [call("foo"), call("bar")]
>>> mock.assert_has_awaits(calls)
Traceback (most recent call last):
...
AssertionError: Awaits not found.
Expected: [call('foo'), call('bar')]
Actual: []
>>> asyncio.run(main('foo'))
>>> asyncio.run(main('bar'))
>>> mock.assert_has_awaits(calls)

assert_not_awaited()

모의 객체가 어웨이트 된 적이 없다고 어서트 합니다.

>>> mock = AsyncMock()
>>> mock.assert_not_awaited()

reset_mock(*args, **kwargs)

Mock.reset_mock()을 참조하십시오. 또한 await_count를 0으로, await_args를 None으로 설정하고, await_args_list를 지웁니다.

await_count

모의 객체가 몇 번 어웨이트 되었는지 추적하는 정수.

>>> mock = AsyncMock()
>>> async def main():
...     await mock()
...
>>> asyncio.run(main())
>>> mock.await_count
1
>>> asyncio.run(main())
>>> mock.await_count
2

await_args

이것은 None(모의 객체가 어웨이트 되지 않았을 때)이거나 모의 객체가 마지막으로 어웨이트 된 인자입니다. Mock.call_args와 같게 기능합니다.

>>> mock = AsyncMock()
>>> async def main(*args):
...     await mock(*args)
...
>>> mock.await_args
>>> asyncio.run(main('foo'))
>>> mock.await_args
call('foo')
>>> asyncio.run(main('bar'))
>>> mock.await_args
call('bar')

await_args_list

이것은 모의 객체에 대한 모든 어웨이트를 순서대로 나열한 리스트입니다 (따라서 리스트의 길이는 어웨이트 한 횟수입니다). 어웨이트 전에는 빈 리스트입니다.

>>> mock = AsyncMock()
>>> async def main(*args):
...     await mock(*args)
...
>>> mock.await_args_list
[]
>>> asyncio.run(main('foo'))
>>> mock.await_args_list
[call('foo')]
>>> asyncio.run(main('bar'))
>>> mock.await_args_list
[call('foo'), call('bar')]

class unittest.mock.ThreadingMock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, *, timeout=UNSET, **kwargs)

A version of MagicMock for multithreading tests. The ThreadingMock object provides extra methods to wait for a call to be invoked, rather than assert on it immediately.

The default timeout is specified by the timeout argument, or if unset by the ThreadingMock.DEFAULT_TIMEOUT attribute, which defaults to blocking (None).

You can configure the global default timeout by setting ThreadingMock.DEFAULT_TIMEOUT.

wait_until_called(*, timeout=UNSET)

Waits until the mock is called.

If a timeout was passed at the creation of the mock or if a timeout argument is passed to this function, the function raises an AssertionError if the call is not performed in time.

>>> mock = ThreadingMock()
>>> thread = threading.Thread(target=mock)
>>> thread.start()
>>> mock.wait_until_called(timeout=1)
>>> thread.join()

wait_until_any_call_with(*args, **kwargs)

Waits until the mock is called with the specified arguments.

If a timeout was passed at the creation of the mock the function raises an AssertionError if the call is not performed in time.

>>> mock = ThreadingMock()
>>> thread = threading.Thread(target=mock, args=("arg1", "arg2",), kwargs={"arg": "thing"})
>>> thread.start()
>>> mock.wait_until_any_call_with("arg1", "arg2", arg="thing")
>>> thread.join()

DEFAULT_TIMEOUT

Global default timeout in seconds to create instances of ThreadingMock.

Added in version 3.13.

호출

모의 객체는 콜러블입니다. 호출은 return_value 어트리뷰트로 설정된 값을 반환합니다. 기본 반환 값은 새로운 Mock 객체입니다; (명시적으로나 Mock을 호출하여) 반환 값에 처음으로 액세스할 때 만들어지지만 - 저장되고 매번 같은 값이 반환됩니다.

객체에 대한 호출은 call_args와 call_args_list 같은 어트리뷰트로 기록됩니다.

If side_effect is set then it will be called after the call has been recorded, so if side_effect raises an exception the call is still recorded.

호출될 때 모의 객체가 예외를 발생시키는 가장 간단한 방법은 side_effect를 예외 클래스나 인스턴스로 만드는 것입니다:

>>> m = MagicMock(side_effect=IndexError)
>>> m(1, 2, 3)
Traceback (most recent call last):
  ...
IndexError
>>> m.mock_calls
[call(1, 2, 3)]
>>> m.side_effect = KeyError('Bang!')
>>> m('two', 'three', 'four')
Traceback (most recent call last):
  ...
KeyError: 'Bang!'
>>> m.mock_calls
[call(1, 2, 3), call('two', 'three', 'four')]

If side_effect is a function then whatever that function returns is what calls to the mock return. The side_effect function is called with the same arguments as the mock. This allows you to vary the return value of the call dynamically, based on the input:

>>> def side_effect(value):
...     return value + 1
...
>>> m = MagicMock(side_effect=side_effect)
>>> m(1)
2
>>> m(2)
3
>>> m.mock_calls
[call(1), call(2)]

If you want the mock to still return the default return value (a new mock), or any set return value, then there are two ways of doing this. Either return return_value from inside side_effect, or return DEFAULT:

>>> m = MagicMock()
>>> def side_effect(*args, **kwargs):
...     return m.return_value
...
>>> m.side_effect = side_effect
>>> m.return_value = 3
>>> m()
3
>>> def side_effect(*args, **kwargs):
...     return DEFAULT
...
>>> m.side_effect = side_effect
>>> m()
3

To remove a side_effect, and return to the default behaviour, set the side_effect to None:

>>> m = MagicMock(return_value=6)
>>> def side_effect(*args, **kwargs):
...     return 3
...
>>> m.side_effect = side_effect
>>> m()
3
>>> m.side_effect = None
>>> m()
6

The side_effect can also be any iterable object. Repeated calls to the mock will return values from the iterable (until the iterable is exhausted and a StopIteration is raised):

>>> m = MagicMock(side_effect=[1, 2, 3])
>>> m()
1
>>> m()
2
>>> m()
3
>>> m()
Traceback (most recent call last):
  ...
StopIteration

이터러블의 멤버가 예외이면 반환되는 대신 예외를 발생시킵니다:

>>> iterable = (33, ValueError, 66)
>>> m = MagicMock(side_effect=iterable)
>>> m()
33
>>> m()
Traceback (most recent call last):
 ...
ValueError
>>> m()
66

어트리뷰트 삭제

모의 객체는 요청 시 어트리뷰트를 만듭니다. 이를 통해 모든 형의 객체인 것처럼 가장할 수 있습니다.

You may want a mock object to return False to a hasattr() call, or raise an AttributeError when an attribute is fetched. You can do this by providing an object as a spec for a mock, but that isn’t always convenient.

어트리뷰트를 삭제하여 어트리뷰트를 “차단”합니다. 일단 삭제되면, 어트리뷰트에 액세스할 때 AttributeError가 발생합니다.

>>> mock = MagicMock()
>>> hasattr(mock, 'm')
True
>>> del mock.m
>>> hasattr(mock, 'm')
False
>>> del mock.f
>>> mock.f
Traceback (most recent call last):
    ...
AttributeError: f

모의 객체 이름과 이름 어트리뷰트

“name”은 Mock 생성자에 대한 인자이므로, 모의 객체가 “name” 어트리뷰트를 가지려면 생성 시 전달할 수 없습니다. 두 가지 대안이 있습니다. 한가지 옵션은 configure_mock()을 사용하는 것입니다:

>>> mock = MagicMock()
>>> mock.configure_mock(name='my_name')
>>> mock.name
'my_name'

더 간단한 옵션은 모의 객체를 만든 후 단순히 “name” 어트리뷰트를 설정하는 것입니다:

>>> mock = MagicMock()
>>> mock.name = "foo"

모의 객체를 어트리뷰트로 연결하기

모의 객체를 다른 모의 객체의 어트리뷰트로 (또는 반환 값으로) 연결하면 그 모의 객체의 “자식”이 됩니다. 자식에 대한 호출은 부모의 method_calls와 mock_calls 어트리뷰트에 기록됩니다. 이는 자식 모의 객체를 구성한 다음 부모에 연결하는 데 유용합니다. 또는 자식들에 대한 모든 호출을 기록하는 부모에 여러 모의 객체를 연결하고 모의 객체 간의 호출 순서에 대한 어서션을 하는 데 유용합니다:

>>> parent = MagicMock()
>>> child1 = MagicMock(return_value=None)
>>> child2 = MagicMock(return_value=None)
>>> parent.child1 = child1
>>> parent.child2 = child2
>>> child1(1)
>>> child2(2)
>>> parent.mock_calls
[call.child1(1), call.child2(2)]

이에 대한 예외는 모의 객체에 이름이 있는 경우입니다. 어떤 이유로든 원하지 않을 때 “부모가 되는 것(parenting)”을 방지 할 수 있습니다.

>>> mock = MagicMock()
>>> not_a_child = MagicMock(name='not-a-child')
>>> mock.attribute = not_a_child
>>> mock.attribute()
<MagicMock name='not-a-child()' id='...'>
>>> mock.mock_calls
[]

patch()가 만든 모의 객체에는 자동으로 이름이 지정됩니다. 부모에게 이름을 가진 모의 객체를 연결하려면 attach_mock() 메서드를 사용하십시오:

>>> thing1 = object()
>>> thing2 = object()
>>> parent = MagicMock()
>>> with patch('__main__.thing1', return_value=None) as child1:
...     with patch('__main__.thing2', return_value=None) as child2:
...         parent.attach_mock(child1, 'child1')
...         parent.attach_mock(child2, 'child2')
...         child1('one')
...         child2('two')
...
>>> parent.mock_calls
[call.child1('one'), call.child2('two')]

[1]

유일한 예외는 매직 메서드와 어트리뷰트(앞뒤에 이중 밑줄을 가진 것)입니다. Mock은 이것을 만들지 않고 대신 AttributeError를 발생시킵니다. 이는 인터프리터가 종종 묵시적으로 이러한 메서드를 요청하고, 매직 메서드를 기대할 때 새 Mock 객체를 얻으면 매우 혼동되기 때문입니다. 매직 메서드 지원이 필요하면 매직 메서드를 참조하십시오.

패처

patch 데코레이터는 데코레이트 하는 함수의 스코프 내에서만 객체를 패치하는 데 사용됩니다. 예외가 발생하더라도 자동으로 패치 해제를 처리합니다. 이러한 함수는 모두 with 문에서 사용될 수 있고, 클래스 데코레이터로도 사용할 수 있습니다.

patch

참고

중요한 것은 올바른 이름 공간에서 패치를 수행하는 것입니다. 패치할 곳 절을 참조하십시오.

unittest.mock.patch(target, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

patch()는 함수 데코레이터, 클래스 데코레이터 또는 컨텍스트 관리자 역할을 합니다. 함수 본문이나 with 문 내부에서, target은 new 객체로 패치됩니다. 함수/with 문이 종료될 때 패치가 복구됩니다.

new가 생략되면, 대상(target)은 패치된 객체가 비동기 함수이면 AsyncMock으로, 그렇지 않으면 MagicMock으로 치환됩니다. patch()가 데코레이터로 사용되고 new가 생략되면, 만들어진 모의 객체는 데코레이트 되는 함수에 대한 추가 인자로 전달됩니다. patch()가 컨텍스트 관리자로 사용되면 만들어진 모의 객체는 컨텍스트 관리자에 의해 반환됩니다.

target은 'package.module.ClassName' 형식의 문자열이어야 합니다. target이 임포트되고 지정된 객체를 new 객체로 치환하므로, patch()를 호출하는 환경에서 target을 임포트 할 수 있어야 합니다. 데코레이트 하는 시간이 아니라 데코레이트 된 함수가 실행될 때 대상(target)을 임포트 합니다.

patch가 여러분을 위해 만든다면 spec과 spec_set 키워드 인자는 MagicMock으로 전달됩니다.

또한 spec=True나 spec_set=True를 전달하면, patch는 모킹되는 객체를 spec/spec_set 객체로 전달합니다.

new_callable을 사용하면 new 객체를 만들기 위해 호출될 다른 클래스나 콜러블 객체를 지정할 수 있습니다. 기본적으로 AsyncMock이 비동기 함수에 사용되고 MagicMock이 나머지에 사용됩니다.

spec의 더 강력한 형태는 autospec입니다. autospec=True를 설정하면 치환될 객체의 사양으로 모의 객체가 만들어집니다. 모의 객체의 모든 어트리뷰트는 또한 치환되는 객체의 해당 어트리뷰트의 사양을 갖습니다. 모킹되는 메서드와 함수는 인자를 검사하고 잘못된 서명으로 호출되면 TypeError를 발생시킵니다. 클래스를 치환하는 모의 객체의 경우, 반환 값(‘인스턴스’)은 클래스와 같은 사양을 갖습니다. create_autospec() 함수와 자동 사양을 참조하십시오.

autospec=True 대신 autospec=some_object를 전달하여 치환되는 것 대신 임의의 객체를 사양으로 사용할 수 있습니다.

기본적으로 patch()는 존재하지 않는 어트리뷰트를 치환하지 못합니다. create=True를 전달하고, 어트리뷰트가 존재하지 않으면, 패치된 함수가 호출될 때 patch가 어트리뷰트를 만들고 패치된 함수가 종료된 후 다시 삭제합니다. 이는 프로덕션 코드가 실행 시간에 만드는 어트리뷰트에 대해 테스트를 작성하는 데 유용합니다. 위험할 수 있어서 기본적으로 꺼져있습니다. 이 기능을 켜면 실제로 존재하지 않는 API에 대해 통과하는 테스트를 작성할 수 있습니다!

참고

버전 3.5에서 변경: 모듈에 있는 내장(builtins)을 패치하는 경우 create=True를 전달할 필요가 없습니다, 기본적으로 추가됩니다.

Patch can be used as a TestCase class decorator. It works by decorating each test method in the class. This reduces the boilerplate code when your test methods share a common patchings set. patch() finds tests by looking for method names that start with patch.TEST_PREFIX. By default this is 'test', which matches the way unittest finds tests. You can specify an alternative prefix by setting patch.TEST_PREFIX.

with 문에서 patch를 컨텍스트 관리자로 사용할 수 있습니다. 여기서 패치는 with 문 다음에 들여쓰기 된 블록에 적용됩니다. “as”를 사용하면 패치된 객체는 “as” 뒤에 오는 이름으로 연결됩니다; patch()가 모의 객체를 만들 때 매우 유용합니다.

patch()는 임의의 키워드 인자를 취합니다. 이들은 만들어질 때 패치되는 객체가 비동기이면 AsyncMock으로, 그렇지 않으면 Mock으로, 또는 지정되면 new_callable로 전달됩니다.

patch.dict(...), patch.multiple(...) 및 patch.object(...)는 대체 사용 사례에 사용할 수 있습니다.

patch()를 함수 데코레이터로 사용하여, 모의 객체를 만들고 데코레이트 된 함수에 전달합니다:

>>> @patch('__main__.SomeClass')
... def function(normal_argument, mock_class):
...     print(mock_class is SomeClass)
...
>>> function(None)
True

클래스를 패치하면 클래스를 MagicMock 인스턴스로 치환합니다. 테스트 대상 코드에서 클래스가 인스턴스 화 되면 사용될 모의 객체의 return_value가 됩니다.

클래스가 여러 번 인스턴스 화 되면 side_effect를 사용하여 매번 새 모의 객체를 반환할 수 있습니다. 또는 return_value를 원하는 것으로 설정할 수 있습니다.

To configure return values on methods of instances on the patched class you must do this on the return_value. For example:

>>> class Class:
...     def method(self):
...         pass
...
>>> with patch('__main__.Class') as MockClass:
...     instance = MockClass.return_value
...     instance.method.return_value = 'foo'
...     assert Class() is instance
...     assert Class().method() == 'foo'
...

spec이나 spec_set을 사용하고 patch()가 클래스를 대체하고 있다면, 만들어진 모의 객체의 반환 값은 같은 사양을 갖습니다.

>>> Original = Class
>>> patcher = patch('__main__.Class', spec=True)
>>> MockClass = patcher.start()
>>> instance = MockClass()
>>> assert isinstance(instance, Original)
>>> patcher.stop()

new_callable 인자는 생성된 모의 객체의 기본 MagicMock에 대한 대체 클래스를 사용하려고 할 때 유용합니다. 예를 들어, NonCallableMock을 사용하려면:

>>> thing = object()
>>> with patch('__main__.thing', new_callable=NonCallableMock) as mock_thing:
...     assert thing is mock_thing
...     thing()
...
Traceback (most recent call last):
  ...
TypeError: 'NonCallableMock' object is not callable

또 다른 사용 사례는 객체를 io.StringIO 인스턴스로 교체하는 것입니다:

>>> from io import StringIO
>>> def foo():
...     print('Something')
...
>>> @patch('sys.stdout', new_callable=StringIO)
... def test(mock_stdout):
...     foo()
...     assert mock_stdout.getvalue() == 'Something\n'
...
>>> test()

patch()가 여러분 대신 모의 객체를 만들 때, 보통 가장 먼저 해야 할 일은 모의 객체를 구성하는 것입니다. 이 구성 중 일부는 patch 호출에서 수행 할 수 있습니다. 호출에 전달하는 임의의 키워드는 만들어진 모의 객체의 어트리뷰트를 설정하는 데 사용됩니다:

>>> patcher = patch('__main__.thing', first='one', second='two')
>>> mock_thing = patcher.start()
>>> mock_thing.first
'one'
>>> mock_thing.second
'two'

만들어진 모의 객체 어트리뷰트뿐만 아니라 자식 모의 객체의 return_value와 side_effect와 같은 어트리뷰트도 구성 할 수 있습니다. 키워드 인자로 직접 전달하는 것은 문법적으로 유효하지 않지만, 이것들을 키로 갖는 딕셔너리는 여전히 **를 사용하여 patch() 호출로 확장될 수 있습니다:

>>> config = {'method.return_value': 3, 'other.side_effect': KeyError}
>>> patcher = patch('__main__.thing', **config)
>>> mock_thing = patcher.start()
>>> mock_thing.method()
3
>>> mock_thing.other()
Traceback (most recent call last):
  ...
KeyError

기본적으로, 존재하지 않는 모듈의 함수(또는 클래스의 메서드나 어트리뷰트)를 패치하려고 시도하면 AttributeError로 실패합니다:

>>> @patch('sys.non_existing_attribute', 42)
... def test():
...     assert sys.non_existing_attribute == 42
...
>>> test()
Traceback (most recent call last):
  ...
AttributeError: <module 'sys' (built-in)> does not have the attribute 'non_existing_attribute'

그러나 patch() 호출에 create=True를 추가하면 이전 예제가 기대한 대로 작동합니다:

>>> @patch('sys.non_existing_attribute', 42, create=True)
... def test(mock_stdout):
...     assert sys.non_existing_attribute == 42
...
>>> test()

버전 3.8에서 변경: patch()는 이제 target이 비동기 함수면 AsyncMock을 반환합니다.

patch.object

patch.object(target, attribute, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

모의 객체로 객체(target)의 이름 있는 멤버(attribute)를 패치합니다.

patch.object()는 데코레이터, 클래스 데코레이터 또는 컨텍스트 관리자로 사용할 수 있습니다. 인자 new, spec, create, spec_set, autospec 및 new_callable은 patch()와 같은 의미입니다. patch()와 마찬가지로, patch.object()는 만드는 모의 객체를 구성하기 위해 임의의 키워드 인자를 취합니다.

클래스 데코레이터로 사용될 때, patch.object()는 감쌀 메서드를 선택하는 데 patch.TEST_PREFIX를 사용합니다.

세 개의 인자나 두 개의 인자로 patch.object()를 호출 할 수 있습니다. 세 개의 인자 형식은 패치 할 객체, 어트리뷰트 이름 및 어트리뷰트를 대체 할 객체를 취합니다.

두 개의 인자 형식으로 호출하면 대체 객체를 생략하고, 모의 객체가 만들어져 데코레이트 된 함수에 대한 추가 인자로 전달됩니다:

>>> @patch.object(SomeClass, 'class_method')
... def test(mock_method):
...     SomeClass.class_method(3)
...     mock_method.assert_called_with(3)
...
>>> test()

spec, create 및 patch.object()에 대한 다른 인자는 patch()와 같은 의미입니다.

patch.dict

patch.dict(in_dict, values=(), clear=False, **kwargs)

Patch a dictionary, or dictionary like object, and restore the dictionary to its original state after the test, where the restored dictionary is a copy of the dictionary as it was before the test.

in_dict는 딕셔너리나 컨테이너와 같은 매핑일 수 있습니다. 매핑이면 적어도 가져오기(get), 설정(set) 및 삭제(delete)와 키 이터레이션을 지원해야 합니다.

in_dict는 딕셔너리 이름을 지정하는 문자열일 수도 있으며, 이때는 임포트 해서 가져옵니다.

values는 딕셔너리에 설정할 값의 딕셔너리일 수 있습니다. values는 (key, value) 쌍의 이터러블일 수도 있습니다.

clear가 참이면 새 값이 설정되기 전에 딕셔너리가 지워집니다.

딕셔너리에 값을 설정하기 위해 임의의 키워드 인자로 patch.dict()를 호출할 수도 있습니다.

버전 3.8에서 변경: patch.dict()는 이제 컨텍스트 관리자로 사용될 때 패치된 딕셔너리를 반환합니다.

patch.dict()는 컨텍스트 관리자, 데코레이터 또는 클래스 데코레이터로 사용할 수 있습니다:

>>> foo = {}
>>> @patch.dict(foo, {'newkey': 'newvalue'})
... def test():
...     assert foo == {'newkey': 'newvalue'}
...
>>> test()
>>> assert foo == {}

클래스 데코레이터로 사용될 때 patch.dict()는 감쌀 메서드를 선택하는 데 patch.TEST_PREFIX(기본값은 'test')를 따릅니다:

>>> import os
>>> import unittest
>>> from unittest.mock import patch
>>> @patch.dict('os.environ', {'newkey': 'newvalue'})
... class TestSample(unittest.TestCase):
...     def test_sample(self):
...         self.assertEqual(os.environ['newkey'], 'newvalue')

테스트에 다른 접두사를 사용하려면, patch.TEST_PREFIX를 설정하여 패처에 다른 접두사를 알릴 수 있습니다. 값을 변경하는 방법에 대한 자세한 내용은 TEST_PREFIX를 참조하십시오.

patch.dict()를 사용하여 멤버를 딕셔너리에 추가하고 (또는 단순히 테스트에서 딕셔너리를 변경하고) 테스트가 끝나면 딕셔너리가 복원되도록 할 수 있습니다.

>>> foo = {}
>>> with patch.dict(foo, {'newkey': 'newvalue'}) as patched_foo:
...     assert foo == {'newkey': 'newvalue'}
...     assert patched_foo == {'newkey': 'newvalue'}
...     # You can add, update or delete keys of foo (or patched_foo, it's the same dict)
...     patched_foo['spam'] = 'eggs'
...
>>> assert foo == {}
>>> assert patched_foo == {}

>>> import os
>>> with patch.dict('os.environ', {'newkey': 'newvalue'}):
...     print(os.environ['newkey'])
...
newvalue
>>> assert 'newkey' not in os.environ

patch.dict() 호출에서 키워드를 사용하여 딕셔너리에 값을 설정할 수 있습니다:

>>> mymodule = MagicMock()
>>> mymodule.function.return_value = 'fish'
>>> with patch.dict('sys.modules', mymodule=mymodule):
...     import mymodule
...     mymodule.function('some', 'args')
...
'fish'

patch.dict() can be used with dictionary like objects that aren’t actually dictionaries. At the very minimum they must support item getting, setting, deleting and either iteration or membership test. This corresponds to the magic methods __getitem__(), __setitem__(), __delitem__() and either __iter__() or __contains__().

>>> class Container:
...     def __init__(self):
...         self.values = {}
...     def __getitem__(self, name):
...         return self.values[name]
...     def __setitem__(self, name, value):
...         self.values[name] = value
...     def __delitem__(self, name):
...         del self.values[name]
...     def __iter__(self):
...         return iter(self.values)
...
>>> thing = Container()
>>> thing['one'] = 1
>>> with patch.dict(thing, one=2, two=3):
...     assert thing['one'] == 2
...     assert thing['two'] == 3
...
>>> assert thing['one'] == 1
>>> assert list(thing) == ['one']

patch.multiple

patch.multiple(target, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

한 번의 호출로 여러 패치를 수행합니다. 패치할 객체(객체나 임포트로 객체를 가져올 문자열로)와 패치에 대한 키워드 인자를 취합니다:

with patch.multiple(settings, FIRST_PATCH='one', SECOND_PATCH='two'):
    ...

patch.multiple()가 모의 객체를 만들기를 원하면 DEFAULT를 값으로 사용하십시오. 이 경우 만들어진 모의 객체는 키워드로 데코레이트 된 함수로 전달되며, patch.multiple()이 컨텍스트 관리자로 사용될 때는 딕셔너리가 반환됩니다.

patch.multiple()은 데코레이터, 클래스 데코레이터 또는 컨텍스트 관리자로 사용할 수 있습니다. spec, spec_set, create, autospec 및 new_callable 인자는 patch()와 같은 의미입니다. 이 인자는 patch.multiple()이 수행한 모든 패치에 적용됩니다.

클래스 데코레이터로 사용될 때 patch.multiple()은 감쌀 메서드를 선택하는 데 patch.TEST_PREFIX를 사용합니다.

patch.multiple()가 모의 객체를 만들기를 원하면 DEFAULT를 값으로 사용할 수 있습니다. patch.multiple()을 데코레이터로 사용하면 만들어진 모의 객체가 키워드로 데코레이트 된 함수에 전달됩니다.

>>> thing = object()
>>> other = object()

>>> @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
... def test_function(thing, other):
...     assert isinstance(thing, MagicMock)
...     assert isinstance(other, MagicMock)
...
>>> test_function()

patch.multiple()은 다른 patch 데코레이터와 중첩될 수 있지만, 키워드로 전달된 인자를 patch()가 만든 모든 표준 인자들 뒤에 넣습니다:

>>> @patch('sys.exit')
... @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
... def test_function(mock_exit, other, thing):
...     assert 'other' in repr(other)
...     assert 'thing' in repr(thing)
...     assert 'exit' in repr(mock_exit)
...
>>> test_function()

patch.multiple()가 컨텍스트 관리자로 사용되면, 컨텍스트 관리자가 반환한 값은 만들어진 모의 객체 이름을 키로 갖는 딕셔너리입니다:

>>> with patch.multiple('__main__', thing=DEFAULT, other=DEFAULT) as values:
...     assert 'other' in repr(values['other'])
...     assert 'thing' in repr(values['thing'])
...     assert values['thing'] is thing
...     assert values['other'] is other
...

패처 메서드: start와 stop

All the patchers have start() and stop() methods. These make it simpler to do patching in setUp methods or where you want to do multiple patches without nesting decorators or with statements.

To use them call patch(), patch.object() or patch.dict() as normal and keep a reference to the returned patcher object. You can then call start() to put the patch in place and stop() to undo it.

patch()를 사용하여 모의 객체를 만들면 patcher.start 호출로 반환됩니다.

>>> patcher = patch('package.module.ClassName')
>>> from package import module
>>> original = module.ClassName
>>> new_mock = patcher.start()
>>> assert module.ClassName is not original
>>> assert module.ClassName is new_mock
>>> patcher.stop()
>>> assert module.ClassName is original
>>> assert module.ClassName is not new_mock

A typical use case for this might be for doing multiple patches in the setUp method of a TestCase:

>>> class MyTest(unittest.TestCase):
...     def setUp(self):
...         self.patcher1 = patch('package.module.Class1')
...         self.patcher2 = patch('package.module.Class2')
...         self.MockClass1 = self.patcher1.start()
...         self.MockClass2 = self.patcher2.start()
...
...     def tearDown(self):
...         self.patcher1.stop()
...         self.patcher2.stop()
...
...     def test_something(self):
...         assert package.module.Class1 is self.MockClass1
...         assert package.module.Class2 is self.MockClass2
...
>>> MyTest('test_something').run()

조심

이 기법을 사용하는 경우 stop을 호출하여 패치가 “실행 취소” 되도록 해야 합니다. setUp에서 예외가 발생하면 tearDown이 호출되지 않기 때문에, 이것은 생각보다 까다로울 수 있습니다. unittest.TestCase.addCleanup()은 이것을 더 쉽게 만듭니다:

>>> class MyTest(unittest.TestCase):
...     def setUp(self):
...         patcher = patch('package.module.Class')
...         self.MockClass = patcher.start()
...         self.addCleanup(patcher.stop)
...
...     def test_something(self):
...         assert package.module.Class is self.MockClass
...

추가 보너스로 더는 patcher 객체에 대한 참조를 유지할 필요가 없습니다.

patch.stopall()을 사용하여 시작된 모든 패치를 중지할 수도 있습니다.

patch.stopall()

모든 활성 패치를 중지합니다. start로 시작한 패치만 중지합니다.

내장 패치

모듈 내의 어떤 내장(builtins)도 패치 할 수 있습니다. 다음 예제는 내장 ord()를 패치합니다:

>>> @patch('__main__.ord')
... def test(mock_ord):
...     mock_ord.return_value = 101
...     print(ord('c'))
...
>>> test()
101

TEST_PREFIX

모든 패처를 클래스 데코레이터로 사용할 수 있습니다. 이런 식으로 사용하면 클래스의 모든 테스트 메서드를 감쌉니다. 패처는 'test'로 시작하는 메서드를 테스트 메서드로 인식합니다. 이것은 unittest.TestLoader가 기본적으로 테스트 메서드를 찾는 것과 같은 방법입니다.

테스트에 다른 접두사를 사용하고 싶을 수도 있습니다. patch.TEST_PREFIX를 설정하여 다른 접두사를 패처에 알릴 수 있습니다:

>>> patch.TEST_PREFIX = 'foo'
>>> value = 3
>>>
>>> @patch('__main__.value', 'not three')
... class Thing:
...     def foo_one(self):
...         print(value)
...     def foo_two(self):
...         print(value)
...
>>>
>>> Thing().foo_one()
not three
>>> Thing().foo_two()
not three
>>> value
3

패치 데코레이터 중첩하기

여러 패치를 수행하려면 단순히 데코레이터를 쌓으면 됩니다.

이 패턴을 사용하여 여러 패치 데코레이터를 쌓을 수 있습니다:

>>> @patch.object(SomeClass, 'class_method')
... @patch.object(SomeClass, 'static_method')
... def test(mock1, mock2):
...     assert SomeClass.static_method is mock1
...     assert SomeClass.class_method is mock2
...     SomeClass.static_method('foo')
...     SomeClass.class_method('bar')
...     return mock1, mock2
...
>>> mock1, mock2 = test()
>>> mock1.assert_called_once_with('foo')
>>> mock2.assert_called_once_with('bar')

데코레이터는 아래에서 위쪽으로 적용됨에 유의하십시오. 이것은 파이썬이 데코레이터를 적용하는 표준 방식입니다. 생성된 모의 객체가 테스트 함수에 전달되는 순서는 이 순서와 일치합니다.

패치할 곳

patch()는 name이 가리키는 객체를 다른 객체로 (임시로) 변경하여 작동합니다. 개별 객체를 가리키는 많은 이름이 있을 수 있어서, 패치가 작동하려면 테스트 대상 시스템에서 사용하는 이름을 패치해야 합니다.

기본 원칙은 객체가 조회되는 곳을 패치하는 것입니다. 이것은 정의된 곳과 반드시 같은 곳일 필요는 없습니다. 몇 가지 예가 이를 명확히 하는 데 도움이 됩니다.

테스트하려는 프로젝트가 다음 구조로 되어 있다고 가정하십시오:

a.py
    -> Defines SomeClass

b.py
    -> from a import SomeClass
    -> some_function instantiates SomeClass

이제 some_function을 테스트하고 싶지만, patch()를 사용하여 SomeClass를 모킹하고 싶습니다. 문제는 모듈 b를 임포트 할 때 모듈 a에서 SomeClass를 임포트해야 한다는 것입니다. patch()를 사용하여 a.SomeClass를 모킹하면 테스트에 영향을 미치지 않습니다; 모듈 b는 이미 실제 SomeClass에 대한 참조를 가지고 있으며 패치가 효과가 없는 것처럼 보입니다.

핵심은 SomeClass가 사용되는 곳(또는 그것을 조회하는 곳)을 패치하는 것입니다. 이 경우 some_function은 우리가 임포트 한 모듈 b에서 SomeClass를 조회합니다. 패치는 다음과 같아야 합니다:

@patch('b.SomeClass')

하지만, from a import SomeClass 대신 모듈 b가 import a를 수행하고 some_function이 a.SomeClass를 사용하는 대체 시나리오를 생각해보십시오. 이 두 가지 임포트 형식은 모두 일반적입니다. 이 경우 패치하려는 클래스가 모듈에서 조회되므로 대신 a.SomeClass를 패치해야 합니다:

@patch('a.SomeClass')

디스크립터와 프락시 객체 패치하기

Both patch and patch.object correctly patch and restore descriptors: class methods, static methods and properties. You should patch these on the class rather than an instance. They also work with some objects that proxy attribute access, like the django settings object [https://web.archive.org/web/20200603181648/http://www.voidspace.org.uk/python/weblog/arch_d7_2010_12_04.shtml#e1198].

MagicMock과 매직 메서드 지원

매직 메서드 모킹하기

Mock supports mocking the Python protocol methods, also known as “magic methods”. This allows mock objects to replace containers or other objects that implement Python protocols.

매직 메서드는 일반 메서드와는 다르게 조회되므로 [2], 이 지원은 특별히 구현되었습니다. 즉, 특정 매직 메서드만 지원됩니다. 지원되는 목록에 이들이 거의 모두 포함됩니다. 누락된 것이 있으면 알려주십시오.

관심 있는 메서드를 함수나 모의 객체 인스턴스로 설정하여 매직 메서드를 모킹합니다. 함수를 사용하면 반드시 self를 첫 번째 인자로 취해야 합니다 [3].

>>> def __str__(self):
...     return 'fooble'
...
>>> mock = Mock()
>>> mock.__str__ = __str__
>>> str(mock)
'fooble'

>>> mock = Mock()
>>> mock.__str__ = Mock()
>>> mock.__str__.return_value = 'fooble'
>>> str(mock)
'fooble'

>>> mock = Mock()
>>> mock.__iter__ = Mock(return_value=iter([]))
>>> list(mock)
[]

이것의 한 가지 사용 사례는 with 문에서 컨텍스트 관리자로 사용되는 객체를 모킹하는 것입니다:

>>> mock = Mock()
>>> mock.__enter__ = Mock(return_value='foo')
>>> mock.__exit__ = Mock(return_value=False)
>>> with mock as m:
...     assert m == 'foo'
...
>>> mock.__enter__.assert_called_with()
>>> mock.__exit__.assert_called_with(None, None, None)

매직 메서드 호출은 method_calls에는 나타나지 않지만, mock_calls에 기록됩니다.

참고

spec 키워드 인자를 사용하여 모의 객체를 만들면 spec에 없는 매직 메서드를 설정하려고 시도할 때 AttributeError가 발생합니다.

지원되는 매직 메서드의 전체 목록은 다음과 같습니다:

__hash__, __sizeof__, __repr__ 및 __str__

__dir__, __format__ 및 __subclasses__

__round__, __floor__, __trunc__ 및 __ceil__

비교: __lt__, __gt__, __le__, __ge__, __eq__ 및 __ne__

컨테이너 메서드: __getitem__, __setitem__, __delitem__, __contains__, __len__, __iter__, __reversed__ 및 __missing__

컨텍스트 관리자: __enter__, __exit__, __aenter__ 및 __aexit__

단항 숫자 메서드: __neg__, __pos__ 및 __invert__

The numeric methods (including right hand and in-place variants): __add__, __sub__, __mul__, __matmul__, __truediv__, __floordiv__, __mod__, __divmod__, __lshift__, __rshift__, __and__, __xor__, __or__, and __pow__

숫자 변환 메서드: __complex__, __int__, __float__ 및 __index__

디스크립터 메서드: __get__, __set__ 및 __delete__

피클링: __reduce__, __reduce_ex__, __getinitargs__, __getnewargs__, __getstate__ 및 __setstate__

파일 시스템 경로 표현: __fspath__

비동기 이터레이션 메서드: __aiter__와 __anext__

버전 3.8에서 변경: os.PathLike.__fspath__()에 대한 지원이 추가되었습니다.

버전 3.8에서 변경: __aenter__, __aexit__, __aiter__ 및 __anext__에 대한 지원이 추가되었습니다.

다음과 같은 메서드가 존재하지만, 모의 객체가 사용 중이거나, 동적으로 설정할 수 없거나, 문제를 일으킬 수 있어서 지원되지 않습니다:

__getattr__, __setattr__, __init__ 및 __new__

__prepare__, __instancecheck__, __subclasscheck__, __del__

매직 모의 객체

두 가지 MagicMock 변형이 있습니다: MagicMock과 NonCallableMagicMock.

class unittest.mock.MagicMock(*args, **kw)

MagicMock is a subclass of Mock with default implementations of most of the magic methods. You can use MagicMock without having to configure the magic methods yourself.

생성자 매개 변수는 Mock과 같은 의미입니다.

spec이나 spec_set 인자를 사용하면 오직 사양에 존재하는 매직 메서드만 만들어집니다.

class unittest.mock.NonCallableMagicMock(*args, **kw)

콜러블이 아닌 MagicMock 버전.

생성자 매개 변수는 콜러블이 아닌 모의 객체에 의미가 없는 return_value와 side_effect를 제외하고 MagicMock과 같은 의미입니다.

매직 메서드는 MagicMock 객체로 설정되므로, 일반적인 방법으로 구성하고 사용할 수 있습니다:

>>> mock = MagicMock()
>>> mock[3] = 'fish'
>>> mock.__setitem__.assert_called_with(3, 'fish')
>>> mock.__getitem__.return_value = 'result'
>>> mock[2]
'result'

기본적으로 많은 프로토콜 메서드는 특정 형의 객체를 반환하도록 요구합니다. 이러한 메서드는 기본 반환 값으로 사전 구성되어 있어서, 반환 값에 관심이 없을 때 아무 조처를 하지 않아도 사용할 수 있습니다. 기본값을 변경하고 싶으면, 여전히 반환 값을 수동으로 설정할 수 있습니다.

메서드와 기본값:

__lt__: NotImplemented

__gt__: NotImplemented

__le__: NotImplemented

__ge__: NotImplemented

__int__: 1

__contains__: False

__len__: 0

__iter__: iter([])

__exit__: False

__aexit__: False

__complex__: 1j

__float__: 1.0

__bool__: True

__index__: 1

__hash__: 모의 객체의 기본 hash

__str__: 모의 객체의 기본 str

__sizeof__: 모의 객체의 기본 sizeof

예를 들면:

>>> mock = MagicMock()
>>> int(mock)
1
>>> len(mock)
0
>>> list(mock)
[]
>>> object() in mock
False

The two equality methods, __eq__() and __ne__(), are special. They do the default equality comparison on identity, using the side_effect attribute, unless you change their return value to return something else:

>>> MagicMock() == 3
False
>>> MagicMock() != 3
True
>>> mock = MagicMock()
>>> mock.__eq__.return_value = True
>>> mock == 3
True

MagicMock.__iter__()의 반환 값은 임의의 이터러블 객체일 수 있으며 이터레이터일 필요는 없습니다:

>>> mock = MagicMock()
>>> mock.__iter__.return_value = ['a', 'b', 'c']
>>> list(mock)
['a', 'b', 'c']
>>> list(mock)
['a', 'b', 'c']

반환 값이 이터레이터면, 일단 이터레이트 하면 이를 소진하고 후속 이터레이션은 빈 목록을 줍니다:

>>> mock.__iter__.return_value = iter(['a', 'b', 'c'])
>>> list(mock)
['a', 'b', 'c']
>>> list(mock)
[]

MagicMock에는 불분명하고 쓸모없는 일부를 제외하고 지원되는 모든 매직 메서드가 구성되어 있습니다. 원한다면 여전히 설정할 수 있습니다.

MagicMock에서 지원되지만, 기본적으로 설정되지 않는 매직 메서드는 다음과 같습니다:

__subclasses__

__dir__

__format__

__get__, __set__ 및 __delete__

__reversed__와 __missing__

__reduce__, __reduce_ex__, __getinitargs__, __getnewargs__, __getstate__ 및 __setstate__

__getformat__

[2]

매직 메서드는 인스턴스가 아닌 클래스에서 조회되어야 합니다. 다른 버전의 파이썬은 이 규칙을 적용하는 데 일관적이지 않습니다. 지원되는 프로토콜 메서드는 지원되는 모든 버전의 파이썬에서 작동해야 합니다.

[3]

이 함수는 기본적으로 클래스에 연결되어 있지만, 각 Mock 인스턴스는 다른 것들과 격리되어 있습니다.

도우미

sentinel

unittest.mock.sentinel

sentinel 객체는 테스트에 고유한(unique) 객체를 제공하는 편리한 방법을 제공합니다.

어트리뷰트는 이름으로 어트리뷰트에 액세스할 때 요청에 따라 만들어집니다. 같은 어트리뷰트에 액세스하면 항상 같은 객체가 반환됩니다. 반환된 객체는 테스트 실패 메시지를 읽을 수 있도록 적절한 repr을 갖습니다.

버전 3.7에서 변경: sentinel 어트리뷰트는 이제 복사되거나 피클될 때 아이덴티티를 유지합니다.

때로 테스트할 때 특정 객체가 다른 메서드에 대한 인자로 전달되거나 반환되는지 테스트해야 할 때가 있습니다. 이것을 테스트하기 위해 이름 붙은 sentinel 객체를 만드는 것이 일반적일 수 있습니다. sentinel은 이와 같은 객체의 아이덴티티를 만들고 테스트하는 편리한 방법을 제공합니다.

이 예에서는 method를 sentinel.some_object를 반환하도록 몽키 패치합니다:

>>> real = ProductionClass()
>>> real.method = Mock(name="method")
>>> real.method.return_value = sentinel.some_object
>>> result = real.method()
>>> assert result is sentinel.some_object
>>> result
sentinel.some_object

DEFAULT

unittest.mock.DEFAULT

DEFAULT 객체는 미리 만들어진 sentinel(실제로 sentinel.DEFAULT)입니다. side_effect 함수에서 일반 반환 값을 사용해야 함을 나타내는 데 사용할 수 있습니다.

call

unittest.mock.call(*args, **kwargs)

call()은 call_args, call_args_list, mock_calls 및 method_calls와 비교할 때, 더 간단한 어서션을 만들기 위한 도우미 객체입니다. call()은 assert_has_calls()와 함께 사용할 수도 있습니다.

>>> m = MagicMock(return_value=None)
>>> m(1, 2, a='foo', b='bar')
>>> m()
>>> m.call_args_list == [call(1, 2, a='foo', b='bar'), call()]
True

call.call_list()

여러 호출을 나타내는 호출 객체의 경우, call_list()는 마지막 호출뿐만 아니라 모든 중간 호출의 목록을 반환합니다.

call_list는 “연쇄 호출(chained calls)”에 대한 어서션을 만드는 데 특히 유용합니다. 연쇄 호출은 한 줄의 코드에 있는 여러 번의 호출입니다. 이로 인해 모의 객체의 mock_calls에 여러 항목이 생성됩니다. 호출 시퀀스를 수동으로 구성하는 것은 지루할 수 있습니다.

call_list()는 같은 연쇄 호출에서 호출 시퀀스를 구성 할 수 있습니다.:

>>> m = MagicMock()
>>> m(1).method(arg='foo').other('bar')(2.0)
<MagicMock name='mock().method().other()()' id='...'>
>>> kall = call(1).method(arg='foo').other('bar')(2.0)
>>> kall.call_list()
[call(1),
 call().method(arg='foo'),
 call().method().other('bar'),
 call().method().other()(2.0)]
>>> m.mock_calls == kall.call_list()
True

call 객체는 구성 방식에 따라 (위치 인자, 키워드 인자)나 (이름, 위치 인자, 키워드 인자)의 튜플입니다. 이것들을 직접 만들 때 특별히 흥미롭지는 않지만, Mock.call_args, Mock.call_args_list 및 Mock.mock_calls 어트리뷰트에 있는 call 객체는 포함된 개별 인자를 얻기 위해 검사될 수 있습니다.

Mock.call_args와 Mock.call_args_list에 있는 call 객체는 (위치 인자, 키워드 인자)의 2-튜플이지만, Mock.mock_calls에 있는 call 객체는, 여러분이 직접 생성하는 객체와 함께, (이름, 위치 인자, 키워드 인자)의 3-튜플입니다.

이들의 “튜플성(tupleness)”을 사용하여 더 복잡한 검사와 어서션을 위해 개별 인자를 가져올 수 있습니다. 위치 인자는 튜플(위치 인자가 없으면 비어있는 튜플)이고 키워드 인자는 딕셔너리입니다:

>>> m = MagicMock(return_value=None)
>>> m(1, 2, 3, arg='one', arg2='two')
>>> kall = m.call_args
>>> kall.args
(1, 2, 3)
>>> kall.kwargs
{'arg': 'one', 'arg2': 'two'}
>>> kall.args is kall[0]
True
>>> kall.kwargs is kall[1]
True

>>> m = MagicMock()
>>> m.foo(4, 5, 6, arg='two', arg2='three')
<MagicMock name='mock.foo()' id='...'>
>>> kall = m.mock_calls[0]
>>> name, args, kwargs = kall
>>> name
'foo'
>>> args
(4, 5, 6)
>>> kwargs
{'arg': 'two', 'arg2': 'three'}
>>> name is m.mock_calls[0][0]
True

create_autospec

unittest.mock.create_autospec(spec, spec_set=False, instance=False, **kwargs)

다른 객체를 사양으로 사용하여 모의 객체를 만듭니다. 모의 객체 어트리뷰트는 spec 객체의 해당 어트리뷰트를 사양으로 사용합니다.

모킹되는 함수나 메서드는 올바른 서명으로 호출되도록 인자를 점검합니다.

spec_set이 True이면 사양 객체에 존재하지 않는 어트리뷰트를 설정하려는 시도는 AttributeError를 발생시킵니다.

클래스가 사양으로 사용되면 모의 객체의 반환 값(클래스의 인스턴스)은 같은 사양을 갖습니다. instance=True를 전달하여 클래스를 인스턴스 객체의 사양으로 사용할 수 있습니다. 반환된 모의 객체는 모의 객체의 인스턴스가 콜러블일 때만 콜러블입니다.

create_autospec()은 또한 만들어진 모의 객체의 생성자에 전달되는 임의의 키워드 인자를 취합니다.

create_autospec()과 patch()에 대한 autospec 인자로 자동 사양을 사용하는 방법에 대한 예는 자동 사양을 참조하십시오.

버전 3.8에서 변경: 대상이 비동기 함수이면 create_autospec()은 이제 AsyncMock을 반환합니다.

ANY

unittest.mock.ANY

때로는 모의 객체 호출에서 인자의 일부에 대한 어서션을 만들 필요가 있지만, 일부 인자에는 신경 쓰지 않거나 call_args에서 개별적으로 꺼내어 더 복잡한 어서션을 만들고 싶을 수도 있습니다.

특정 인자를 무시하려면 모든 것과 같다고 비교되는 객체를 전달할 수 있습니다. assert_called_with()와 assert_called_once_with()에 대한 호출은 전달된 내용과 관계없이 성공합니다.

>>> mock = Mock(return_value=None)
>>> mock('foo', bar=object())
>>> mock.assert_called_once_with('foo', bar=ANY)

ANY는 mock_calls와 같은 호출 리스트와 비교할 때도 사용할 수 있습니다.:

>>> m = MagicMock(return_value=None)
>>> m(1)
>>> m(1, 2)
>>> m(object())
>>> m.mock_calls == [call(1), call(1, 2), ANY]
True

ANY is not limited to comparisons with call objects and so can also be used in test assertions:

class TestStringMethods(unittest.TestCase):

    def test_split(self):
        s = 'hello world'
        self.assertEqual(s.split(), ['hello', ANY])

FILTER_DIR

unittest.mock.FILTER_DIR

FILTER_DIR is a module level variable that controls the way mock objects respond to dir(). The default is True, which uses the filtering described below, to only show useful members. If you dislike this filtering, or need to switch it off for diagnostic purposes, then set mock.FILTER_DIR = False.

필터링을 켜면, dir(some_mock)는 유용한 어트리뷰트만 표시하고 일반적으로 표시되지 않는 동적으로 만들어진 어트리뷰트를 포함합니다. spec(또는 물론 autospec)으로 모의 객체를 만들었으면, 아직 액세스하지 않았다 할지라도 원본의 모든 어트리뷰트가 표시됩니다:

>>> dir(Mock())
['assert_any_call',
 'assert_called',
 'assert_called_once',
 'assert_called_once_with',
 'assert_called_with',
 'assert_has_calls',
 'assert_not_called',
 'attach_mock',
 ...
>>> from urllib import request
>>> dir(Mock(spec=request))
['AbstractBasicAuthHandler',
 'AbstractDigestAuthHandler',
 'AbstractHTTPHandler',
 'BaseHandler',
 ...

Mock에 대해 dir()을 호출한 결과에서 그다지 유용하지 않은 (모킹되는 대상이 아닌 Mock 전용) 밑줄과 이중 밑줄 접두어 어트리뷰트가 필터링 되었습니다. 이 동작이 마음에 들지 않으면 모듈 수준 스위치 FILTER_DIR를 설정하여 끌 수 있습니다.:

>>> from unittest import mock
>>> mock.FILTER_DIR = False
>>> dir(mock.Mock())
['_NonCallableMock__get_return_value',
 '_NonCallableMock__get_side_effect',
 '_NonCallableMock__return_value_doc',
 '_NonCallableMock__set_return_value',
 '_NonCallableMock__set_side_effect',
 '__call__',
 '__class__',
 ...

Alternatively you can just use vars(my_mock) (instance members) and dir(type(my_mock)) (type members) to bypass the filtering irrespective of FILTER_DIR.

mock_open

unittest.mock.mock_open(mock=None, read_data=None)

open()의 사용을 대체하기 위한 모의 객체를 만드는 도우미 함수. 직접 호출되거나 컨텍스트 관리자로 사용되는 open()에 대해 작동합니다.

mock 인자는 구성할 모의 객체입니다. None(기본값)이면 표준 파일 핸들에서 사용 가능한 메서드나 어트리뷰트로 API가 제한된 MagicMock이 만들어집니다.

read_data is a string for the read(), readline(), and readlines() methods of the file handle to return. Calls to those methods will take data from read_data until it is depleted. The mock of these methods is pretty simplistic: every time the mock is called, the read_data is rewound to the start. If you need more control over the data that you are feeding to the tested code you will need to customize this mock for yourself. When that is insufficient, one of the in-memory filesystem packages on PyPI [https://pypi.org] can offer a realistic filesystem for testing.

버전 3.4에서 변경: Added readline() and readlines() support. The mock of read() changed to consume read_data rather than returning it on each call.

버전 3.5에서 변경: read_data는 이제 mock을 호출할 때마다 재설정됩니다.

버전 3.8에서 변경: Added __iter__() to implementation so that iteration (such as in for loops) correctly consumes read_data.

open()을 컨텍스트 관리자로 사용하는 것은 파일 핸들이 올바르게 닫히도록 보장하는 좋은 방법이고 점차 일반화되고 있습니다:

with open('/some/path', 'w') as f:
    f.write('something')

The issue is that even if you mock out the call to open() it is the returned object that is used as a context manager (and has __enter__() and __exit__() called).

MagicMock으로 컨텍스트 관리자를 모킹하는 것은 도우미 함수가 유용할 만큼 충분히 일반적입니다.

>>> m = mock_open()
>>> with patch('__main__.open', m):
...     with open('foo', 'w') as h:
...         h.write('some stuff')
...
>>> m.mock_calls
[call('foo', 'w'),
 call().__enter__(),
 call().write('some stuff'),
 call().__exit__(None, None, None)]
>>> m.assert_called_once_with('foo', 'w')
>>> handle = m()
>>> handle.write.assert_called_once_with('some stuff')

그리고 파일을 읽기 위해서는:

>>> with patch('__main__.open', mock_open(read_data='bibble')) as m:
...     with open('foo') as h:
...         result = h.read()
...
>>> m.assert_called_once_with('foo')
>>> assert result == 'bibble'

자동 사양

Autospeccing is based on the existing spec feature of mock. It limits the api of mocks to the api of an original object (the spec), but it is recursive (implemented lazily) so that attributes of mocks only have the same api as the attributes of the spec. In addition mocked functions / methods have the same call signature as the original so they raise a TypeError if they are called incorrectly.

자동 사양이 작동하는 방식을 설명하기 전에, 이것이 필요한 이유는 이렇습니다.

Mock is a very powerful and flexible object, but it suffers from a flaw which is general to mocking. If you refactor some of your code, rename members and so on, any tests for code that is still using the old api but uses mocks instead of the real objects will still pass. This means your tests can all pass even though your code is broken.

버전 3.5에서 변경: Before 3.5, tests with a typo in the word assert would silently pass when they should raise an error. You can still achieve this behavior by passing unsafe=True to Mock.

이것이 단위 테스트뿐만 아니라 통합 테스트가 필요한 또 다른 이유입니다. 모든 것을 분리해서 테스트하는 것은 괜찮고 멋지지만, 단위들이 어떻게 “서로 연결되어” 있는지 테스트하지 않으면 테스트가 발견할 수도 있을 버그에 대한 여지가 여전히 많습니다.

unittest.mock already provides a feature to help with this, called speccing. If you use a class or instance as the spec for a mock then you can only access attributes on the mock that exist on the real class:

>>> from urllib import request
>>> mock = Mock(spec=request.Request)
>>> mock.assret_called_with  # Intentional typo!
Traceback (most recent call last):
 ...
AttributeError: Mock object has no attribute 'assret_called_with'

사양은 모의 객체 자체에만 적용되므로, 모의 객체의 메서드와 관계된 문제는 여전히 있습니다:

>>> mock.has_data()
<mock.Mock object at 0x...>
>>> mock.has_data.assret_called_with()  # Intentional typo!

자동 사양은 이 문제를 해결합니다. autospec=True를 patch() / patch.object()로 전달하거나 create_autospec() 함수를 사용하여 사양이 있는 모의 객체를 만들 수 있습니다. autospec=True 인자를 patch()에 사용하면 대체 중인 객체가 사양 객체로 사용됩니다. 사양화(speccing)는 “게으르게(lazily)” 수행되므로 (모의 객체의 어트리뷰트에 액세스할 때 사양이 만들어집니다) 성능이 크게 저하되지 않고도 매우 복잡하거나 깊이 중첩된 객체(가령 모듈을 임포트 하는 모듈을 임포트 하는 모듈)와 함께 사용할 수 있습니다.

사용 예는 다음과 같습니다:

>>> from urllib import request
>>> patcher = patch('__main__.request', autospec=True)
>>> mock_request = patcher.start()
>>> request is mock_request
True
>>> mock_request.Request
<MagicMock name='request.Request' spec='Request' id='...'>

You can see that request.Request has a spec. request.Request takes two arguments in the constructor (one of which is self). Here’s what happens if we try to call it incorrectly:

>>> req = request.Request()
Traceback (most recent call last):
 ...
TypeError: <lambda>() takes at least 2 arguments (1 given)

사양은 인스턴스 화 된 클래스(즉, 사양화된 모의 객체의 반환 값)에도 적용됩니다:

>>> req = request.Request('foo')
>>> req
<NonCallableMagicMock name='request.Request()' spec='Request' id='...'>

Request objects are not callable, so the return value of instantiating our mocked out request.Request is a non-callable mock. With the spec in place any typos in our asserts will raise the correct error:

>>> req.add_header('spam', 'eggs')
<MagicMock name='request.Request().add_header()' id='...'>
>>> req.add_header.assret_called_with  # Intentional typo!
Traceback (most recent call last):
 ...
AttributeError: Mock object has no attribute 'assret_called_with'
>>> req.add_header.assert_called_with('spam', 'eggs')

많은 경우 단지 기존 patch() 호출에 autospec=True를 추가하면 오타와 api 변경으로 인한 버그로부터 보호할 수 있습니다.

patch()를 통해 autospec을 사용하는 것뿐만 아니라 자동 사양 모의 객체를 직접 만들기 위한 create_autospec()도 있습니다:

>>> from urllib import request
>>> mock_request = create_autospec(request)
>>> mock_request.Request('foo', 'bar')
<NonCallableMagicMock name='mock.Request()' spec='Request' id='...'>

그러나 경고와 제한이 없는 것은 아니기 때문에 기본 동작이 아닙니다. 사양 객체에서 사용 가능한 어트리뷰트를 알기 위해 autospec은 사양을 검사(어트리뷰트를 액세스합니다)해야 합니다. 모의 객체 어트리뷰트를 탐색할 때 원본 객체의 대응하는 탐색이 수면 아래에서 발생합니다. 사양 객체 중 어느 하나가 코드 실행을 트리거 할 수 있는 프로퍼티나 디스크립터를 갖는 경우 자동 사양을 사용하지 못할 수 있습니다. 반면에, 내부 검사가 안전하도록 객체를 설계하는 것이 훨씬 좋습니다 [4].

A more serious problem is that it is common for instance attributes to be created in the __init__() method and not to exist on the class at all. autospec can’t know about any dynamically created attributes and restricts the api to visible attributes.

>>> class Something:
...   def __init__(self):
...     self.a = 33
...
>>> with patch('__main__.Something', autospec=True):
...   thing = Something()
...   thing.a
...
Traceback (most recent call last):
  ...
AttributeError: Mock object has no attribute 'a'

이 문제를 해결하는 방법에는 몇 가지가 있습니다. 가장 쉬운, 하지만 가장 덜 성가시다고 할 수는 없는, 방법은 단순히 생성 후에 모의 객체에 필요한 어트리뷰트를 설정하는 것입니다. autospec은 사양에 존재하지 않는 어트리뷰트를 꺼내는 것을 허락하지 않기 때문에 그것을 설정하는 것을 막지는 않습니다:

>>> with patch('__main__.Something', autospec=True):
...   thing = Something()
...   thing.a = 33
...

존재하지 않는 어트리뷰트를 설정하지 못하게 하는 spec과 autospec의 더 적극적인 버전이 있습니다. 이것은 코드가 오직 유효한 어트리뷰트만 설정하도록 보장하려는 경우 유용하지만, 명백히 이 특정 시나리오를 막습니다:

>>> with patch('__main__.Something', autospec=True, spec_set=True):
...   thing = Something()
...   thing.a = 33
...
Traceback (most recent call last):
 ...
AttributeError: Mock object has no attribute 'a'

Probably the best way of solving the problem is to add class attributes as default values for instance members initialised in __init__(). Note that if you are only setting default attributes in __init__() then providing them via class attributes (shared between instances of course) is faster too. e.g.

class Something:
    a = 33

이것은 또 다른 문제를 일으킵니다. 나중에 다른 형의 객체가 될 멤버에 대해 기본값 None을 제공하는 것이 일반적입니다. 아무런 어트리뷰트나 메서드에도 액세스할 수 없도록 하므로 None은 사양으로 쓸모가 없습니다. None은 결코 스펙으로 유용하지 않고, 일반적으로 다른 형의 멤버를 나타낼 것이기 때문에, autospec은 None으로 설정된 멤버의 사양을 사용하지 않습니다. 이것들은 평범한 모의 객체일 것입니다 (아마도 - MagicMock):

>>> class Something:
...     member = None
...
>>> mock = create_autospec(Something)
>>> mock.member.foo.bar.baz()
<MagicMock name='mock.member.foo.bar.baz()' id='...'>

프로덕션 클래스를 수정하여 기본값을 추가하는 것이 마음에 들지 않으면 더 많은 선택지가 있습니다. 이 중 하나는 단순히 클래스가 아닌 인스턴스를 사양으로 사용하는 것입니다. 다른 하나는 프로덕션 클래스의 서브 클래스를 만들고 프로덕션 클래스에 영향을 주지 않으면서 기본값을 서브 클래스에 추가하는 것입니다. 이 두 가지 모두 사양으로 대체 객체를 사용해야 합니다. 고맙게도 patch()는 이것을 지원합니다 - 단순히 대체 객체를 autospec 인자로 전달할 수 있습니다:

>>> class Something:
...   def __init__(self):
...     self.a = 33
...
>>> class SomethingForTest(Something):
...   a = 33
...
>>> p = patch('__main__.Something', autospec=SomethingForTest)
>>> mock = p.start()
>>> mock.a
<NonCallableMagicMock name='Something.a' spec='int' id='...'>

[4]

이것은 클래스나 이미 인스턴스 화 된 객체에만 적용됩니다. 모킹된 클래스를 호출하여 모의 객체 인스턴스를 만드는 것은 실제 인스턴스를 만들지 않습니다. (dir() 호출과 함께) 어트리뷰트 조회만 수행됩니다.

실링 모의 객체 봉인하기

unittest.mock.seal(mock)

Seal은 봉인되는 모의 객체나 이것의 재귀적으로 이미 모의 객체인 어트리뷰트의 어트리뷰트를 액세스할 때 자동 모의 객체 생성을 비활성화합니다.

이름이나 사양을 가진 모의 객체 인스턴스가 어트리뷰트에 대입되면 봉인 체인에서 고려되지 않습니다. 이것은 seal이 모의 객체의 일부를 고정하는 것을 방지할 수 있게 합니다.

>>> mock = Mock()
>>> mock.submock.attribute1 = 2
>>> mock.not_submock = mock.Mock(name="sample_name")
>>> seal(mock)
>>> mock.new_attribute  # This will raise AttributeError.
>>> mock.submock.attribute2  # This will raise AttributeError.
>>> mock.not_submock.attribute2  # This won't raise.

Added in version 3.7.

Order of precedence of side_effect, return_value and wraps

The order of their precedence is:

side_effect

return_value

wraps

If all three are set, mock will return the value from side_effect, ignoring return_value and the wrapped object altogether. If any two are set, the one with the higher precedence will return the value. Regardless of the order of which was set first, the order of precedence remains unchanged.

>>> from unittest.mock import Mock
>>> class Order:
...     @staticmethod
...     def get_value():
...         return "third"
...
>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.get_value.side_effect = ["first"]
>>> order_mock.get_value.return_value = "second"
>>> order_mock.get_value()
'first'

As None is the default value of side_effect, if you reassign its value back to None, the order of precedence will be checked between return_value and the wrapped object, ignoring side_effect.

>>> order_mock.get_value.side_effect = None
>>> order_mock.get_value()
'second'

If the value being returned by side_effect is DEFAULT, it is ignored and the order of precedence moves to the successor to obtain the value to return.

>>> from unittest.mock import DEFAULT
>>> order_mock.get_value.side_effect = [DEFAULT]
>>> order_mock.get_value()
'second'

When Mock wraps an object, the default value of return_value will be DEFAULT.

>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.return_value
sentinel.DEFAULT
>>> order_mock.get_value.return_value
sentinel.DEFAULT

The order of precedence will ignore this value and it will move to the last successor which is the wrapped object.

As the real call is being made to the wrapped object, creating an instance of this mock will return the real instance of the class. The positional arguments, if any, required by the wrapped object must be passed.

>>> order_mock_instance = order_mock()
>>> isinstance(order_mock_instance, Order)
True
>>> order_mock_instance.get_value()
'third'

>>> order_mock.get_value.return_value = DEFAULT
>>> order_mock.get_value()
'third'

>>> order_mock.get_value.return_value = "second"
>>> order_mock.get_value()
'second'

But if you assign None to it, this will not be ignored as it is an explicit assignment. So, the order of precedence will not move to the wrapped object.

>>> order_mock.get_value.return_value = None
>>> order_mock.get_value() is None
True

Even if you set all three at once when initializing the mock, the order of precedence remains the same:

>>> order_mock = Mock(spec=Order, wraps=Order,
...                   **{"get_value.side_effect": ["first"],
...                      "get_value.return_value": "second"}
...                   )
...
>>> order_mock.get_value()
'first'
>>> order_mock.get_value.side_effect = None
>>> order_mock.get_value()
'second'
>>> order_mock.get_value.return_value = DEFAULT
>>> order_mock.get_value()
'third'

If side_effect is exhausted, the order of precedence will not cause a value to be obtained from the successors. Instead, StopIteration exception is raised.

>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.get_value.side_effect = ["first side effect value",
...                                     "another side effect value"]
>>> order_mock.get_value.return_value = "second"

>>> order_mock.get_value()
'first side effect value'
>>> order_mock.get_value()
'another side effect value'

>>> order_mock.get_value()
Traceback (most recent call last):
 ...
StopIteration

unittest.mock — getting started

Added in version 3.3.

모의 객체 사용하기

메서드를 패치하는 모의 객체

Mock 객체의 일반적인 용도는 다음과 같습니다:

메서드 패치하기

객체에 대한 메서드 호출 기록하기

객체의 메서드를 대체하여 시스템의 다른 부분에서 올바른 인자로 호출되었는지 확인할 수 있습니다:

>>> real = SomeClass()
>>> real.method = MagicMock(name='method')
>>> real.method(3, 4, 5, key='value')
<MagicMock name='method()' id='...'>

일단 모의 객체가 사용되면 (이 예제에서는 real.method) 사용 방법에 대한 어서션을 만들 수 있도록 하는 메서드와 어트리뷰트를 제공합니다.

참고

이 예의 대부분에서 Mock과 MagicMock 클래스는 교환할 수 있습니다. MagicMock이 더 유능한 클래스이기 때문에 기본 사용하기에 적합합니다.

일단 모의 객체가 호출되면 그것의 called 어트리뷰트가 True로 설정됩니다. 더 중요하게 assert_called_with()나 assert_called_once_with() 메서드를 사용하여 올바른 인자로 호출되었는지 확인할 수 있습니다.

이 예제는 ProductionClass().method를 호출하면 something 메서드가 호출되는지 테스트합니다:

>>> class ProductionClass:
...     def method(self):
...         self.something(1, 2, 3)
...     def something(self, a, b, c):
...         pass
...
>>> real = ProductionClass()
>>> real.something = MagicMock()
>>> real.method()
>>> real.something.assert_called_once_with(1, 2, 3)

객체의 메서드 호출을 위한 모의 객체

마지막 예제에서 우리는 객체에 메서드를 직접 패치하여 올바르게 호출되었는지 확인했습니다. 또 다른 일반적인 사용 사례는 객체를 메서드(또는 테스트 중인 시스템의 일부)에 전달한 다음 올바른 방식으로 사용되는지 확인하는 것입니다.

아래의 간단한 ProductionClass에는 closer 메서드가 있습니다. 객체로 호출되면 그것의 close를 호출합니다.

>>> class ProductionClass:
...     def closer(self, something):
...         something.close()
...

따라서 테스트하려면 close 메서드를 가진 객체를 전달하고 올바르게 호출되었는지 확인해야 합니다.

>>> real = ProductionClass()
>>> mock = Mock()
>>> real.closer(mock)
>>> mock.close.assert_called_with()

모의 객체에 ‘close’ 메서드를 제공하기 위해 어떤 작업도 수행할 필요가 없습니다. close에 액세스하면 만들어집니다. 따라서, ‘close’가 아직 호출되지 않았다면 테스트에서 액세스할 때 만들어지지만, assert_called_with()는 실패 예외를 발생시킵니다.

클래스 모킹하기

일반적인 사용 사례는 테스트 중인 코드가 인스턴스 화하는 클래스를 모킹하는 것입니다. 클래스를 패치하면, 해당 클래스가 모의 객체로 바뀝니다. 인스턴스는 클래스를 호출해서 만들어집니다. 이는 모킹된 클래스의 반환 값을 확인하여 “모의 인스턴스”에 액세스한다는 것을 뜻합니다.

아래 예제에는 Foo를 인스턴스 화하고 그것의 메서드를 호출하는 some_function 함수가 있습니다. patch()에 대한 호출은 클래스 Foo를 모의 객체로 대체합니다. Foo 인스턴스는 모의 객체를 호출한 결과라서, 모의 객체 return_value를 수정하여 구성됩니다.

>>> def some_function():
...     instance = module.Foo()
...     return instance.method()
...
>>> with patch('module.Foo') as mock:
...     instance = mock.return_value
...     instance.method.return_value = 'the result'
...     result = some_function()
...     assert result == 'the result'

모의 객체 이름 붙이기

모의 객체에 이름을 지정하는 것이 유용할 수 있습니다. 이름은 모의 객체의 repr에 표시되며 모의 객체가 테스트 실패 메시지에 나타날 때 유용할 수 있습니다. 이 이름은 모의 객체의 어트리뷰트나 메서드에도 전파됩니다:

>>> mock = MagicMock(name='foo')
>>> mock
<MagicMock name='foo' id='...'>
>>> mock.method
<MagicMock name='foo.method' id='...'>

모든 호출 추적하기

메서드에 대한 단일 호출 이상을 추적하려는 경우가 종종 있습니다. mock_calls 어트리뷰트는 모의 객체의 자식 어트리뷰트에 대한 모든 호출을 기록합니다 - 그리고 그들의 자식에 대해서도 마찬가지입니다.

>>> mock = MagicMock()
>>> mock.method()
<MagicMock name='mock.method()' id='...'>
>>> mock.attribute.method(10, x=53)
<MagicMock name='mock.attribute.method()' id='...'>
>>> mock.mock_calls
[call.method(), call.attribute.method(10, x=53)]

mock_calls에 대한 어서션을 만들고 예기치 않은 메서드가 호출되면, 어서션이 실패합니다. 이 기능은 예상한 호출이 이루어졌음을 어서트 할 뿐만 아니라, 추가 호출 없이 올바른 순서로 호출되었는지 확인하기 때문에 유용합니다:

call 객체를 사용하여 mock_calls와 비교할 리스트를 구성합니다:

>>> expected = [call.method(), call.attribute.method(10, x=53)]
>>> mock.mock_calls == expected
True

그러나, 모의 객체를 반환하는 호출에 대한 매개 변수는 기록되지 않아서, 조상을 만드는 데 사용되는 매개 변수가 중요한 중첩된 호출을 추적할 수 없습니다:

>>> m = Mock()
>>> m.factory(important=True).deliver()
<Mock name='mock.factory().deliver()' id='...'>
>>> m.mock_calls[-1] == call.factory(important=False).deliver()
True

반환 값과 어트리뷰트 설정하기

모의 객체에서 반환 값을 설정하는 것은 아주 간단합니다:

>>> mock = Mock()
>>> mock.return_value = 3
>>> mock()
3

물론 모의 객체의 메서드에 대해서도 마찬가지입니다:

>>> mock = Mock()
>>> mock.method.return_value = 3
>>> mock.method()
3

생성자에서 반환 값을 설정할 수도 있습니다:

>>> mock = Mock(return_value=3)
>>> mock()
3

모의 객체에 어트리뷰트 설정이 필요하면, 그냥 하면 됩니다:

>>> mock = Mock()
>>> mock.x = 3
>>> mock.x
3

때로는 예를 들어 mock.connection.cursor().execute("SELECT 1")와 같은 더 복잡한 상황을 모킹하고 싶을 수도 있습니다. 이 호출이 리스트를 반환하도록 하려면, 중첩 호출의 결과를 구성해야 합니다.

call을 사용하여 다음과 같이 “연쇄 호출(chained call)”로 일련의 호출 집합을 구성할 수 있습니다:

>>> mock = Mock()
>>> cursor = mock.connection.cursor.return_value
>>> cursor.execute.return_value = ['foo']
>>> mock.connection.cursor().execute("SELECT 1")
['foo']
>>> expected = call.connection.cursor().execute("SELECT 1").call_list()
>>> mock.mock_calls
[call.connection.cursor(), call.connection.cursor().execute('SELECT 1')]
>>> mock.mock_calls == expected
True

.call_list() 호출이 호출 객체를 연쇄 호출을 나타내는 호출 리스트로 변환합니다.

모의 객체로 예외 발생시키기

유용한 어트리뷰트는 side_effect입니다. 이것을 예외 클래스나 인스턴스로 설정하면 모의 객체가 호출될 때 예외가 발생합니다.

>>> mock = Mock(side_effect=Exception('Boom!'))
>>> mock()
Traceback (most recent call last):
  ...
Exception: Boom!

부작용 함수와 이터러블

side_effect는 함수나 이터러블로 설정할 수도 있습니다. side_effect의 이터러블로서의 사용 사례는 모의 객체가 여러 번 호출되고, 각 호출이 다른 값을 반환하기를 원하는 곳입니다. side_effect를 이터러블로 설정하면 모의 객체에 대한 모든 호출은 이터러블에서 다음 값을 반환합니다:

>>> mock = MagicMock(side_effect=[4, 5, 6])
>>> mock()
4
>>> mock()
5
>>> mock()
6

모의 객체 호출에 전달되는 것에 따라 반환 값을 동적으로 변경하는 것과 같은 고급 사용 사례의 경우, side_effect는 함수가 될 수 있습니다. 함수는 모의 객 체와 같은 인자로 호출됩니다. 함수가 반환하는 것을 호출이 반환합니다:

>>> vals = {(1, 2): 1, (2, 3): 2}
>>> def side_effect(*args):
...     return vals[args]
...
>>> mock = MagicMock(side_effect=side_effect)
>>> mock(1, 2)
1
>>> mock(2, 3)
2

비동기 이터레이터 모킹하기

파이썬 3.8부터, AsyncMock과 MagicMock은 __aiter__를 통해 비동기 이터레이터(Asynchronous Iterators)를 모킹하는 것을 지원합니다. __aiter__의 return_value 어트리뷰트를 사용하여 이터레이션에 사용될 반환 값을 설정할 수 있습니다.

>>> mock = MagicMock()  # AsyncMock also works here
>>> mock.__aiter__.return_value = [1, 2, 3]
>>> async def main():
...     return [i async for i in mock]
...
>>> asyncio.run(main())
[1, 2, 3]

비동기 컨텍스트 관리자 모킹하기

파이썬 3.8부터, AsyncMock과 MagicMock은 __aenter__와 __aexit__를 통해 비동기 컨텍스트 관리자를 모킹하는 것을 지원합니다. 기본적으로, __aenter__와 __aexit__는 비동기 함수를 반환하는 AsyncMock 인스턴스입니다.

>>> class AsyncContextManager:
...     async def __aenter__(self):
...         return self
...     async def __aexit__(self, exc_type, exc, tb):
...         pass
...
>>> mock_instance = MagicMock(AsyncContextManager())  # AsyncMock also works here
>>> async def main():
...     async with mock_instance as result:
...         pass
...
>>> asyncio.run(main())
>>> mock_instance.__aenter__.assert_awaited_once()
>>> mock_instance.__aexit__.assert_awaited_once()

기존 객체에서 모의 객체 만들기

모킹을 과도하게 사용하는 한 가지 문제는 테스트를 실제 코드가 아닌 모킹의 구현에 연결한다는 것입니다. some_method를 구현하는 클래스가 있다고 가정해봅시다. 다른 클래스에 대한 테스트에서, some_method*도* 제공하는 이 객체의 모의 객체를 제공합니다. 나중에 첫 번째 클래스를 리팩토링하여, 더는 some_method를 갖지 않습니다 - 그러면 이제 코드가 망가졌음에도 테스트는 계속 통과합니다!

Mock은 spec 키워드 인자를 사용하여, 모의 객체를 위한 사양으로 객체를 제공할 수 있도록 합니다. 사양 객체에 존재하지 않는 모의 객체의 메서드/어트리뷰트에 액세스하면 어트리뷰트 에러가 즉시 발생합니다. 사양의 구현을 변경하면, 해당 클래스를 사용하는 테스트는 해당 테스트에서 클래스를 인스턴스 화하지 않고도 즉시 실패하기 시작합니다.

>>> mock = Mock(spec=SomeClass)
>>> mock.old_method()
Traceback (most recent call last):
   ...
AttributeError: Mock object has no attribute 'old_method'. Did you mean: 'class_method'?

또한 사양을 사용하면 일부 매개 변수가 위치 인자나 이름 붙인 인자 중 어느 것으로 전달되는지와 관계없이 모의 객체에 대한 호출을 더 스마트하게 일치시킬 수 있도록 합니다:

>>> def f(a, b, c): pass
...
>>> mock = Mock(spec=f)
>>> mock(1, 2, 3)
<Mock name='mock()' id='140161580456576'>
>>> mock.assert_called_with(a=1, b=2, c=3)

이 더 스마트한 인치가 모의 객체에 대한 메서드 호출에서도 작동하게 하려면, 자동 사양을 사용할 수 있습니다.

임의의 어트리뷰트를 읽는 것뿐만 아니라 설정하지 못하게 하는 더 강력한 사양 형식을 원하면 spec 대신 spec_set을 사용할 수 있습니다.

Using side_effect to return per file content

mock_open() is used to patch open() method. side_effect can be used to return a new Mock object per call. This can be used to return different contents per file stored in a dictionary:

DEFAULT = "default"
data_dict = {"file1": "data1",
             "file2": "data2"}

def open_side_effect(name):
    return mock_open(read_data=data_dict.get(name, DEFAULT))()

with patch("builtins.open", side_effect=open_side_effect):
    with open("file1") as file1:
        assert file1.read() == "data1"

    with open("file2") as file2:
        assert file2.read() == "data2"

    with open("file3") as file2:
        assert file2.read() == "default"

패치 데코레이터

참고

patch()를 사용할 때는 그것이 조회되는 이름 공간에서 객체를 패치하는 것이 중요합니다. 이것은 일반적으로 간단하지만, 빠른 안내를 위해 패치할 곳을 읽으십시오.

테스트에서 흔히 필요한 것은 클래스 어트리뷰트나 모듈 어트리뷰트를 패치하는 것입니다, 예를 들어 내장(builtin)을 패치하거나 모듈에 있는 인스턴스 화 되는 클래스를 패치하는 것. 모듈과 클래스는 사실상 전역이라서, 테스트 후에 패치를 실행 취소해야 합니다, 그렇지 않으면 패치가 다른 테스트로 지속하여, 진단하기 어려운 문제를 일으킵니다.

mock은 세 가지 편리한 데코레이터를 제공합니다: patch(), patch.object() 및 patch.dict(). patch는 패치 할 어트리뷰트를 지정하기 위해 package.module.Class.attribute 형식의 단일 문자열을 취합니다. 또한 선택적으로 어트리뷰트(또는 클래스나 무엇이건)를 바꾸려는 값을 취합니다. ‘patch.object’는 객체와 패치하려는 어트리뷰트의 이름 및 선택적으로 패치 할 값을 취합니다.

patch.object:

>>> original = SomeClass.attribute
>>> @patch.object(SomeClass, 'attribute', sentinel.attribute)
... def test():
...     assert SomeClass.attribute == sentinel.attribute
...
>>> test()
>>> assert SomeClass.attribute == original

>>> @patch('package.module.attribute', sentinel.attribute)
... def test():
...     from package.module import attribute
...     assert attribute is sentinel.attribute
...
>>> test()

모듈(builtins를 포함하는)을 패치하려면 patch.object() 대신 patch()를 사용하십시오:

>>> mock = MagicMock(return_value=sentinel.file_handle)
>>> with patch('builtins.open', mock):
...     handle = open('filename', 'r')
...
>>> mock.assert_called_with('filename', 'r')
>>> assert handle == sentinel.file_handle, "incorrect file handle returned"

필요하면 package.module 형식으로 모듈 이름을 ‘점으로 표시’할 수 있습니다:

>>> @patch('package.module.ClassName.attribute', sentinel.attribute)
... def test():
...     from package.module import ClassName
...     assert ClassName.attribute == sentinel.attribute
...
>>> test()

좋은 패턴은 실제로 테스트 메서드 자체를 데코레이트 하는 것입니다:

>>> class MyTest(unittest.TestCase):
...     @patch.object(SomeClass, 'attribute', sentinel.attribute)
...     def test_something(self):
...         self.assertEqual(SomeClass.attribute, sentinel.attribute)
...
>>> original = SomeClass.attribute
>>> MyTest('test_something').test_something()
>>> assert SomeClass.attribute == original

Mock으로 패치하려면, 하나의 인자만으로 patch()를 사용할 수 있습니다 (또는 두 개의 인자로 patch.object()). 모의 객체가 여러분을 위해 만들어지고 테스트 함수 / 메서드로 전달됩니다:

>>> class MyTest(unittest.TestCase):
...     @patch.object(SomeClass, 'static_method')
...     def test_something(self, mock_method):
...         SomeClass.static_method()
...         mock_method.assert_called_with()
...
>>> MyTest('test_something').test_something()

이 패턴을 사용하여 여러 패치 데코레이터를 쌓을 수 있습니다:

>>> class MyTest(unittest.TestCase):
...     @patch('package.module.ClassName1')
...     @patch('package.module.ClassName2')
...     def test_something(self, MockClass2, MockClass1):
...         self.assertIs(package.module.ClassName1, MockClass1)
...         self.assertIs(package.module.ClassName2, MockClass2)
...
>>> MyTest('test_something').test_something()

패치 데코레이터를 중첩할 때 모의 객체는 적용한 순서와 같은 순서(데코레이터가 적용되는 일반적인 파이썬 순서)로 데코레이트 된 함수로 전달됩니다. 이것은 밑에서 위로 올라가는 순서를 뜻해서, 위의 예에서 test_module.ClassName2의 모의 객체가 먼저 전달됩니다.

스코프 도중 딕셔너리에 값을 설정하고 테스트가 끝날 때 딕셔너리를 원래 상태로 복원하기 위한 patch.dict()도 있습니다:

>>> foo = {'key': 'value'}
>>> original = foo.copy()
>>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
...     assert foo == {'newkey': 'newvalue'}
...
>>> assert foo == original

patch, patch.object 및 patch.dict는 모두 컨텍스트 관리자로 사용할 수 있습니다.

patch()를 사용하여 모의 객체를 만드는 곳에서, with 문의 “as” 형식을 사용하여 모의 객체에 대한 참조를 얻을 수 있습니다:

>>> class ProductionClass:
...     def method(self):
...         pass
...
>>> with patch.object(ProductionClass, 'method') as mock_method:
...     mock_method.return_value = None
...     real = ProductionClass()
...     real.method(1, 2, 3)
...
>>> mock_method.assert_called_with(1, 2, 3)

대안으로 patch, patch.object 및 patch.dict는 클래스 데코레이터로 사용될 수 있습니다. 이런 식으로 사용될 때 이름이 “test”로 시작하는 모든 메서드에 데코레이터를 개별적으로 적용하는 것과 같습니다.

추가 예

다음은 약간 더 고급 시나리오에 대한 몇 가지 예입니다.

연쇄 호출 모킹하기

일단 return_value 어트리뷰트를 이해하면 연쇄 호출 모킹은 모의 객체를 사용하면 실제로 간단합니다. 모의 객체가 처음 호출되거나 호출되기 전에 return_value를 가져오면, 새 Mock이 만들어집니다.

이것은 return_value 모의 객체를 조사하여 모킹 된 객체에 대한 호출에서 반환된 객체가 어떻게 사용되었는지 확인할 수 있음을 뜻합니다:

>>> mock = Mock()
>>> mock().foo(a=2, b=3)
<Mock name='mock().foo()' id='...'>
>>> mock.return_value.foo.assert_called_with(a=2, b=3)

여기서부터는 구성하고 연쇄 호출에 대한 어서션을 만드는 간단한 단계입니다. 물론 또 다른 대안은 처음부터 더 테스트하기 쉬운 방식으로 코드를 작성하는 것입니다…

그래서, 다음과 같은 코드가 있다고 가정합시다:

>>> class Something:
...     def __init__(self):
...         self.backend = BackendProvider()
...     def method(self):
...         response = self.backend.get_endpoint('foobar').create_call('spam', 'eggs').start_call()
...         # more code

BackendProvider 가 이미 잘 테스트 되었다고 가정하면, method()를 어떻게 테스트해야 할까요? 특히, 코드 섹션 # more code가 response 객체를 올바른 방식으로 사용하는지 테스트하고 싶습니다.

이 호출의 연쇄는 인스턴스 어트리뷰트에서 이루어지기 때문에 Something 인스턴스에서 backend 어트리뷰트를 몽키 패치 할 수 있습니다. 이 특별한 경우에는 start_call에 대한 최종 호출의 반환 값에만 관심이 있어서 해야 할 구성이 많지 않습니다. 반환하는 객체가 ‘파일류(file-like)’라고 가정하고, response 객체가 spec으로 내장 open()을 사용하도록 할 것입니다.

이를 위해 모의 백 엔드로 모의 인스턴스를 만들고 모의 response 객체를 만듭니다. 응답을 최종 start_call의 반환 값으로 설정하기 위해 다음을 수행할 수 있습니다:

mock_backend.get_endpoint.return_value.create_call.return_value.start_call.return_value = mock_response

configure_mock() 메서드를 사용하여 약간 더 좋은 방법으로 반환 값을 직접 설정할 수 있습니다:

>>> something = Something()
>>> mock_response = Mock(spec=open)
>>> mock_backend = Mock()
>>> config = {'get_endpoint.return_value.create_call.return_value.start_call.return_value': mock_response}
>>> mock_backend.configure_mock(**config)

이것들로 우리는 “모의 백 엔드”를 몽키 패치하고 실제 호출을 할 수 있습니다:

>>> something.backend = mock_backend
>>> something.method()

mock_calls를 사용하면 단일 어서션으로 연쇄 호출을 확인할 수 있습니다. 연쇄 호출은 한 줄의 코드에 있는 여러 번의 호출이라서, mock_calls에는 여러 항목이 있게 됩니다. call.call_list()를 사용하여 이 호출의 리스트를 만들 수 있습니다:

>>> chained = call.get_endpoint('foobar').create_call('spam', 'eggs').start_call()
>>> call_list = chained.call_list()
>>> assert mock_backend.mock_calls == call_list

부분 모킹

In some tests I wanted to mock out a call to datetime.date.today() to return a known date, but I didn’t want to prevent the code under test from creating new date objects. Unfortunately datetime.date is written in C, and so I couldn’t just monkey-patch out the static datetime.date.today() method.

date 클래스를 모의 객체로 효과적으로 래핑하지만, 생성자 호출은 실제 클래스로 전달하는 (그리고 진짜 인스턴스를 반환하는) 간단한 방법을 찾았습니다.

The patch decorator is used here to mock out the date class in the module under test. The side_effect attribute on the mock date class is then set to a lambda function that returns a real date. When the mock date class is called a real date will be constructed and returned by side_effect.

>>> from datetime import date
>>> with patch('mymodule.date') as mock_date:
...     mock_date.today.return_value = date(2010, 10, 8)
...     mock_date.side_effect = lambda *args, **kw: date(*args, **kw)
...
...     assert mymodule.date.today() == date(2010, 10, 8)
...     assert mymodule.date(2009, 6, 8) == date(2009, 6, 8)

datetime.date를 전역적으로 패치하지 않았음에 유의하십시오. date를 사용하는 모듈에서 패치했습니다. 패치할 곳을 참조하십시오.

date.today()가 호출되면 알려진 날짜가 반환되지만, date(...) 생성자에 대한 호출은 여전히 일반 date를 반환합니다. 이렇게 하지 않으면 테스트 중인 코드와 정확히 같은 알고리즘을 사용하여 예상 결과를 계산해야 할 수 있습니다, 이는 고전적인 테스트 안티 패턴입니다.

date 생성자에 대한 호출은 mock_date 어트리뷰트(call_count와 그 친구들)에 기록되며 테스트에 유용할 수 있습니다.

date나 기타 내장 클래스 모킹을 처리하는 다른 방법은 이 블로그 페이지 [https://williambert.online/2011/07/how-to-unit-testing-in-django-with-mocking-and-patching/]에서 다루고 있습니다.

제너레이터 메서드 모킹하기

파이썬 제너레이터는 yield 문을 사용하는 함수나 메서드로, 이터레이트 할 때 일련의 값을 반환합니다 [1].

제너레이터 메서드 / 함수가 호출되면 제너레이터 객체를 반환합니다. 이터레이트 하는 대상은 제너레이터 객체입니다. 이터레이션을 위한 프로토콜 메서드는 __iter__()이고, MagicMock을 사용하여 이를 모킹 할 수 있습니다.

다음은 제너레이터로 구현된 “iter” 메서드를 갖는 예제 클래스입니다:

>>> class Foo:
...     def iter(self):
...         for i in [1, 2, 3]:
...             yield i
...
>>> foo = Foo()
>>> list(foo.iter())
[1, 2, 3]

이 클래스, 특히 “iter” 메서드를 어떻게 모킹할까요?

이터레이션(list 호출로 인해 묵시적으로 이루어집니다)에서 반환된 값을 구성하려면, foo.iter() 호출에 의해 반환된 객체를 구성해야 합니다.

>>> mock_foo = MagicMock()
>>> mock_foo.iter.return_value = iter([1, 2, 3])
>>> list(mock_foo.iter())
[1, 2, 3]

[1]

제너레이터 표현식과 제너레이터의 더 고급 사용 [http://www.dabeaz.com/coroutines/index.html]도 있지만, 여기서는 다루지 않습니다. 제너레이터와 이것이 얼마나 강력한지에 대한 아주 좋은 소개: Generator Tricks for Systems Programmers [http://www.dabeaz.com/generators/].

모든 테스트 메서드에 같은 패치 적용하기

If you want several patches in place for multiple test methods the obvious way is to apply the patch decorators to every method. This can feel like unnecessary repetition. Instead, you can use patch() (in all its various forms) as a class decorator. This applies the patches to all test methods on the class. A test method is identified by methods whose names start with test:

>>> @patch('mymodule.SomeClass')
... class MyTest(unittest.TestCase):
...
...     def test_one(self, MockSomeClass):
...         self.assertIs(mymodule.SomeClass, MockSomeClass)
...
...     def test_two(self, MockSomeClass):
...         self.assertIs(mymodule.SomeClass, MockSomeClass)
...
...     def not_a_test(self):
...         return 'something'
...
>>> MyTest('test_one').test_one()
>>> MyTest('test_two').test_two()
>>> MyTest('test_two').not_a_test()
'something'

패치를 관리하는 다른 방법은 패처 메서드: start와 stop을 사용하는 것입니다. 이를 통해 패치를 setUp과 tearDown 메서드로 옮길 수 있습니다.

>>> class MyTest(unittest.TestCase):
...     def setUp(self):
...         self.patcher = patch('mymodule.foo')
...         self.mock_foo = self.patcher.start()
...
...     def test_foo(self):
...         self.assertIs(mymodule.foo, self.mock_foo)
...
...     def tearDown(self):
...         self.patcher.stop()
...
>>> MyTest('test_foo').run()

이 기법을 사용하면 stop을 호출하여 패치가 “실행 취소”되도록 해야 합니다. setUp에서 예외가 발생하면 tearDown이 호출되지 않기 때문에, 생각보다 복잡할 수 있습니다. unittest.TestCase.addCleanup()은 이것을 더 쉽게 만듭니다:

>>> class MyTest(unittest.TestCase):
...     def setUp(self):
...         patcher = patch('mymodule.foo')
...         self.addCleanup(patcher.stop)
...         self.mock_foo = patcher.start()
...
...     def test_foo(self):
...         self.assertIs(mymodule.foo, self.mock_foo)
...
>>> MyTest('test_foo').run()

연결되지 않은 메서드 모킹하기

오늘 테스트를 작성하는 동안 연결되지 않은 메서드(unbound method)를 패치해야 했습니다 (인스턴스가 아닌 클래스의 메서드를 패치하는 것입니다). 어떤 객체가 이 특정 메서드를 호출했는지에 대한 어서션을 하고 싶기 때문에 첫 번째 인자로 self가 전달되는 것이 필요했습니다. 문제는 이것을 위해 모의 객체로 패치 할 수 없다는 것인데, 연결되지 않은 메서드를 모의 객체로 바꾸면 인스턴스에서 가져올 때 연결된 메서드가 되지 않아서, self가 전달되지 않기 때문입니다. 해결 방법은 연결되지 않은 메서드를 실제 함수로 대신 패치하는 것입니다. patch() 데코레이터는 메서드를 모의 객체로 패치하기 너무 쉽게 만들어서 실제 함수를 만들어야 하는 것이 성가십니다.

autospec=True를 패치로 전달하면 실제 함수 객체로 패치가 수행됩니다. 이 함수 객체는 그것이 교체하는 것과 같은 서명을 갖지만, 수면 아래에서 모의 객체로 위임합니다. 전과 똑같은 방식으로 여전히 자동 생성된 모의 객체를 얻습니다. 그것이 의미하는 것은, 클래스에서 연결되지 않은 메서드를 패치하는데 사용하면 모킹 된 함수가 인스턴스에서 꺼낼 때 연결된 메서드로 바뀐다는 것입니다. self가 첫 번째 인자로 전달되고, 정확히 제가 원하는 것입니다:

>>> class Foo:
...   def foo(self):
...     pass
...
>>> with patch.object(Foo, 'foo', autospec=True) as mock_foo:
...   mock_foo.return_value = 'foo'
...   foo = Foo()
...   foo.foo()
...
'foo'
>>> mock_foo.assert_called_once_with(foo)

autospec=True를 사용하지 않으면 연결되지 않은 메서드가 대신 Mock 인스턴스로 패치되고, self로 호출되지 않습니다.

모의 객체로 여러 호출 확인하기

mock에는 모의 객체가 어떻게 사용되는지에 대한 어서션을 만드는 데 유용한 API가 있습니다.

>>> mock = Mock()
>>> mock.foo_bar.return_value = None
>>> mock.foo_bar('baz', spam='eggs')
>>> mock.foo_bar.assert_called_with('baz', spam='eggs')

If your mock is only being called once you can use the assert_called_once_with() method that also asserts that the call_count is one.

>>> mock.foo_bar.assert_called_once_with('baz', spam='eggs')
>>> mock.foo_bar()
>>> mock.foo_bar.assert_called_once_with('baz', spam='eggs')
Traceback (most recent call last):
    ...
AssertionError: Expected 'foo_bar' to be called once. Called 2 times.
Calls: [call('baz', spam='eggs'), call()].

assert_called_with와 assert_called_once_with는 모두 가장 최근 호출에 대한 어서션을 합니다. 모의 객체가 여러 번 호출될 것이고, 이 호출 모두에 대해 어서션을 하고 싶다면 call_args_list를 사용할 수 있습니다:

>>> mock = Mock(return_value=None)
>>> mock(1, 2, 3)
>>> mock(4, 5, 6)
>>> mock()
>>> mock.call_args_list
[call(1, 2, 3), call(4, 5, 6), call()]

call 도우미를 사용하면 이러한 호출에 대한 어서션을 쉽게 할 수 있습니다. 예상 호출 리스트를 만들어서 call_args_list와 비교할 수 있습니다. 이것은 call_args_list의 repr과 매우 유사합니다:

>>> expected = [call(1, 2, 3), call(4, 5, 6), call()]
>>> mock.call_args_list == expected
True

가변 인자에 대처하기

드물지만 여러분을 괴롭힐 수 있는 또 다른 상황은 모의 객체가 가변 인자로 호출되는 경우입니다. call_args와 call_args_list는 인자에 대한 참조를 저장합니다. 테스트 중인 코드에 의해 인자가 변경되면 모의 객체가 호출되었을 때의 값에 대해 더는 어서션 할 수 없습니다.

다음은 문제를 보여주는 예제 코드입니다. ‘mymodule’에 정의된 다음 함수를 상상해보십시오:

def frob(val):
    pass

def grob(val):
    "First frob and then clear val"
    frob(val)
    val.clear()

grob이 올바른 인자로 frob을 호출하는지 테스트하려고 할 때 어떤 일이 발생하는지 보십시오:

>>> with patch('mymodule.frob') as mock_frob:
...     val = {6}
...     mymodule.grob(val)
...
>>> val
set()
>>> mock_frob.assert_called_with({6})
Traceback (most recent call last):
    ...
AssertionError: Expected: (({6},), {})
Called with: ((set(),), {})

한가지 가능성은 모의 객체가 전달한 인자를 복사하는 것일 수 있습니다. 그러면 동일성(equality)을 위해 객체 아이덴티티에 의존하는 어서션을 수행하면 문제가 발생할 수 있습니다.

Here’s one solution that uses the side_effect functionality. If you provide a side_effect function for a mock then side_effect will be called with the same args as the mock. This gives us an opportunity to copy the arguments and store them for later assertions. In this example I’m using another mock to store the arguments so that I can use the mock methods for doing the assertion. Again a helper function sets this up for me.

>>> from copy import deepcopy
>>> from unittest.mock import Mock, patch, DEFAULT
>>> def copy_call_args(mock):
...     new_mock = Mock()
...     def side_effect(*args, **kwargs):
...         args = deepcopy(args)
...         kwargs = deepcopy(kwargs)
...         new_mock(*args, **kwargs)
...         return DEFAULT
...     mock.side_effect = side_effect
...     return new_mock
...
>>> with patch('mymodule.frob') as mock_frob:
...     new_mock = copy_call_args(mock_frob)
...     val = {6}
...     mymodule.grob(val)
...
>>> new_mock.assert_called_with({6})
>>> new_mock.call_args
call({6})

copy_call_args는 호출될 모의로 호출됩니다. 어서션을 수행할 새로운 모의 객체를 반환합니다. side_effect 함수는 인자의 사본을 만들고 사본으로 new_mock을 호출합니다.

참고

모의 객체를 한 번만 사용하려는 경우 호출 시점에서 인자를 확인하는 쉬운 방법이 있습니다. 단순히 side_effect 함수 내에서 확인할 수 있습니다.

>>> def side_effect(arg):
...     assert arg == {6}
...
>>> mock = Mock(side_effect=side_effect)
>>> mock({6})
>>> mock(set())
Traceback (most recent call last):
    ...
AssertionError

다른 접근법은 인자를 복사(copy.deepcopy()를 사용해서)하는 Mock이나 MagicMock의 서브 클래스를 만드는 것입니다. 구현 예는 다음과 같습니다:

>>> from copy import deepcopy
>>> class CopyingMock(MagicMock):
...     def __call__(self, /, *args, **kwargs):
...         args = deepcopy(args)
...         kwargs = deepcopy(kwargs)
...         return super().__call__(*args, **kwargs)
...
>>> c = CopyingMock(return_value=None)
>>> arg = set()
>>> c(arg)
>>> arg.add(1)
>>> c.assert_called_with(set())
>>> c.assert_called_with(arg)
Traceback (most recent call last):
    ...
AssertionError: expected call not found.
Expected: mock({1})
Actual: mock(set())
>>> c.foo
<CopyingMock name='mock.foo' id='...'>

Mock이나 MagicMock을 서브 클래싱할 때 모든 동적으로 만들어진 어트리뷰트와 return_value는 자동으로 서브 클래스를 사용합니다. 즉, CopyingMock의 모든 자식도 CopyingMock 형이 됩니다.

중첩 패치

patch를 컨텍스트 관리자로 것이 멋지기는 하지만, 여러 패치를 수행하면 오른쪽으로 점점 더 들여쓰기 되는 문장으로 중첩될 수 있습니다:

>>> class MyTest(unittest.TestCase):
...
...     def test_foo(self):
...         with patch('mymodule.Foo') as mock_foo:
...             with patch('mymodule.Bar') as mock_bar:
...                 with patch('mymodule.Spam') as mock_spam:
...                     assert mymodule.Foo is mock_foo
...                     assert mymodule.Bar is mock_bar
...                     assert mymodule.Spam is mock_spam
...
>>> original = mymodule.Foo
>>> MyTest('test_foo').test_foo()
>>> assert mymodule.Foo is original

unittest cleanup 함수와 패처 메서드: start와 stop을 사용하면 중첩된 들여쓰기 없이 같은 효과를 얻을 수 있습니다. 간단한 도우미 메서드인 create_patch는 제 자리에서 패치를 설치하고 만들어진 모의 객체를 반환합니다:

>>> class MyTest(unittest.TestCase):
...
...     def create_patch(self, name):
...         patcher = patch(name)
...         thing = patcher.start()
...         self.addCleanup(patcher.stop)
...         return thing
...
...     def test_foo(self):
...         mock_foo = self.create_patch('mymodule.Foo')
...         mock_bar = self.create_patch('mymodule.Bar')
...         mock_spam = self.create_patch('mymodule.Spam')
...
...         assert mymodule.Foo is mock_foo
...         assert mymodule.Bar is mock_bar
...         assert mymodule.Spam is mock_spam
...
>>> original = mymodule.Foo
>>> MyTest('test_foo').run()
>>> assert mymodule.Foo is original

MagicMock으로 딕셔너리 모킹하기

딕셔너리나 다른 컨테이너 객체를 모킹하여, 여전히 딕셔너리처럼 동작하면서 이에 대한 모든 액세스를 기록하고 싶을 수 있습니다.

딕셔너리처럼 동작하는 MagicMock을 사용하고 side_effect가 딕셔너리 액세스를 우리의 제어하에 있는 실제 하부 딕셔너리로 위임하게 해서 목적을 달성할 수 있습니다.

When the __getitem__() and __setitem__() methods of our MagicMock are called (normal dictionary access) then side_effect is called with the key (and in the case of __setitem__ the value too). We can also control what is returned.

MagicMock이 사용된 후에 call_args_list와 같은 어트리뷰트를 사용하여 딕셔너리가 어떻게 사용되었는지를 어서트할 수 있습니다:

>>> my_dict = {'a': 1, 'b': 2, 'c': 3}
>>> def getitem(name):
...      return my_dict[name]
...
>>> def setitem(name, val):
...     my_dict[name] = val
...
>>> mock = MagicMock()
>>> mock.__getitem__.side_effect = getitem
>>> mock.__setitem__.side_effect = setitem

참고

MagicMock을 사용하는 대신 Mock을 사용하고 오직 원하는 매직 메서드만 제공할 수 있습니다:

>>> mock = Mock()
>>> mock.__getitem__ = Mock(side_effect=getitem)
>>> mock.__setitem__ = Mock(side_effect=setitem)

세 번째 옵션은 MagicMock을 사용하지만, dict를 spec (또는 spec_set) 인자로 전달하여 만들어진 MagicMock이 딕셔너리 매직 메서드 만 갖도록 하는 것입니다:

>>> mock = MagicMock(spec_set=dict)
>>> mock.__getitem__.side_effect = getitem
>>> mock.__setitem__.side_effect = setitem

이러한 부작용 함수가 제자리에 들어가면, mock은 일반 딕셔너리처럼 작동하지만, 액세스를 기록합니다. 존재하지 않는 키에 액세스하려고 하면 KeyError를 발생시키기조차 합니다.

>>> mock['a']
1
>>> mock['c']
3
>>> mock['d']
Traceback (most recent call last):
    ...
KeyError: 'd'
>>> mock['b'] = 'fish'
>>> mock['d'] = 'eggs'
>>> mock['b']
'fish'
>>> mock['d']
'eggs'

사용된 후에 일반적인 모의 객체 메서드와 어트리뷰트를 사용하여 액세스에 대한 어서션을 할 수 있습니다:

>>> mock.__getitem__.call_args_list
[call('a'), call('c'), call('d'), call('b'), call('d')]
>>> mock.__setitem__.call_args_list
[call('b', 'fish'), call('d', 'eggs')]
>>> my_dict
{'a': 1, 'b': 'fish', 'c': 3, 'd': 'eggs'}

Mock 서브 클래스와 그 어트리뷰트

Mock을 서브 클래싱하려는 여러 가지 이유가 있습니다. 한 가지 이유는 도우미 메서드를 추가하는 것입니다. 다음은 시시한 예입니다:

>>> class MyMock(MagicMock):
...     def has_been_called(self):
...         return self.called
...
>>> mymock = MyMock(return_value=None)
>>> mymock
<MyMock id='...'>
>>> mymock.has_been_called()
False
>>> mymock()
>>> mymock.has_been_called()
True

Mock 인스턴스의 표준 동작은 어트리뷰트와 반환 값 모의 객체가 액세스 되는 모의 객체의 형과 같은 형이라는 것입니다. 이를 통해 Mock 어트리뷰트는 Mock이고 MagicMock 어트리뷰트는 MagicMock이 됩니다 [2]. 따라서 도우미 메서드를 추가하기 위해 서브 클래싱하면 이 메서드는 서브 클래스 인스턴스의 어트리뷰트와 반환 값 모의 객체에서도 사용할 수 있습니다.

>>> mymock.foo
<MyMock name='mock.foo' id='...'>
>>> mymock.foo.has_been_called()
False
>>> mymock.foo()
<MyMock name='mock.foo()' id='...'>
>>> mymock.foo.has_been_called()
True

Sometimes this is inconvenient. For example, one user [https://code.google.com/archive/p/mock/issues/105] is subclassing mock to created a Twisted adaptor [https://twisted.org/documents/11.0.0/api/twisted.python.components.html]. Having this applied to attributes too actually causes errors.

Mock(이것의 모든 종류에서)은 _get_child_mock이라는 메서드를 사용하여 어트리뷰트와 반환 값을 위한 이러한 “서브 모의 객체”를 만듭니다. 이 메서드를 재정의하여 서브 클래스가 어트리뷰트에 사용되지 않도록 할 수 있습니다. 서명은 모의 객체 생성자에 전달되는 임의의 키워드 인자(**kwargs)를 취하는 것입니다:

>>> class Subclass(MagicMock):
...     def _get_child_mock(self, /, **kwargs):
...         return MagicMock(**kwargs)
...
>>> mymock = Subclass()
>>> mymock.foo
<MagicMock name='mock.foo' id='...'>
>>> assert isinstance(mymock, Subclass)
>>> assert not isinstance(mymock.foo, Subclass)
>>> assert not isinstance(mymock(), Subclass)

[2]

이 규칙의 예외는 콜러블이 아닌 모의 객체입니다. 어트리뷰트는 콜러블 변형을 사용하는데, 그렇지 않으면 콜러블이 아닌 모의 객체가 콜러블 메서드를 가질 수 없기 때문입니다.

patch.dict로 임포트를 모킹하기

모킹이 어려울 수 있는 한 가지 상황은 함수 내부에 지역 임포트가 있는 경우입니다. 이것들은 모킹하기가 더 어려운데, 우리가 패치 할 수 있는 모듈 이름 공간의 객체를 사용하지 않기 때문입니다.

일반적으로 지역 임포트는 피해야 합니다. 그것들은 때때로 순환 의존성을 막기 위해 수행되는데, 보통 문제를 해결하는 더 좋은 방법(코드를 리팩터 하십시오)이 있습니다. 또는 임포트를 지연시켜서 “선불 비용”을 방지하기 위해 수행합니다. 이 또한 무조건적인 지역 임포트보다 더 나은 방법으로 해결할 수 있습니다 (모듈을 클래스나 모듈 어트리뷰트로 저장하고 처음 사용할 때만 임포트 합니다).

That aside there is a way to use mock to affect the results of an import. Importing fetches an object from the sys.modules dictionary. Note that it fetches an object, which need not be a module. Importing a module for the first time results in a module object being put in sys.modules, so usually when you import something you get a module back. This need not be the case however.

즉, patch.dict()를 사용하여 임시로 sys.modules에 모의 객체를 넣을 수 있습니다. 이 패치가 활성화되어있는 동안 모든 임포트는 모의 객체를 가져옵니다. 패치가 완료되면 (데코레이트 된 함수가 종료되거나, with 문 본문이 완료되거나 patcher.stop()이 호출되면) 이전에 있던 모든 것이 안전하게 복원됩니다.

다음은 ‘fooble’ 모듈을 모킹하는 예입니다.

>>> import sys
>>> mock = Mock()
>>> with patch.dict('sys.modules', {'fooble': mock}):
...    import fooble
...    fooble.blob()
...
<Mock name='mock.blob()' id='...'>
>>> assert 'fooble' not in sys.modules
>>> mock.blob.assert_called_once_with()

보시다시피 import fooble은 성공하지만, 끝났을 때 sys.modules에는 ‘fooble’이 남아 있지 않습니다.

이것은 from module import name 형식에서도 작동합니다:

>>> mock = Mock()
>>> with patch.dict('sys.modules', {'fooble': mock}):
...    from fooble import blob
...    blob.blip()
...
<Mock name='mock.blob.blip()' id='...'>
>>> mock.blob.blip.assert_called_once_with()

약간의 추가 작업으로 패키지 임포트를 모킹 할 수도 있습니다:

>>> mock = Mock()
>>> modules = {'package': mock, 'package.module': mock.module}
>>> with patch.dict('sys.modules', modules):
...    from package.module import fooble
...    fooble()
...
<Mock name='mock.module.fooble()' id='...'>
>>> mock.module.fooble.assert_called_once_with()

호출 순서 추적과 덜 상세한 호출 어서션

Mock 클래스를 사용하면 method_calls 어트리뷰트를 통해 모의 객체에서 메서드 호출의 순서를 추적할 수 있습니다. 개별 모의 객체 간의 호출 순서를 추적할 수는 없지만, mock_calls를 사용하여 같은 효과를 얻을 수 있습니다.

모의 객체들은 mock_calls에서 자식 모의 객체에 대한 호출을 추적하고, 모의 객체의 임의 어트리뷰트에 액세스하면 자식 모의 객체를 만들기 때문에, 부모 모의 객체로부터 개별 모의 객체를 만들 수 있습니다. 그러면 해당 자식 모의 객체에 대한 호출은 부모의 mock_calls에 순서대로 기록됩니다:

>>> manager = Mock()
>>> mock_foo = manager.foo
>>> mock_bar = manager.bar

>>> mock_foo.something()
<Mock name='mock.foo.something()' id='...'>
>>> mock_bar.other.thing()
<Mock name='mock.bar.other.thing()' id='...'>

>>> manager.mock_calls
[call.foo.something(), call.bar.other.thing()]

그런 다음 관리자 모의 객체의 mock_calls 어트리뷰트와 비교하여 순서를 포함하여 호출에 대해 어서션 할 수 있습니다:

>>> expected_calls = [call.foo.something(), call.bar.other.thing()]
>>> manager.mock_calls == expected_calls
True

patch가 모의 객체를 만들고 제자리에 배치하는 경우, attach_mock() 메서드를 사용하여 모의 객체를 관리자 모의 객체에 연결할 수 있습니다. 연결 후 호출은 관리자의 mock_calls에 기록됩니다.

>>> manager = MagicMock()
>>> with patch('mymodule.Class1') as MockClass1:
...     with patch('mymodule.Class2') as MockClass2:
...         manager.attach_mock(MockClass1, 'MockClass1')
...         manager.attach_mock(MockClass2, 'MockClass2')
...         MockClass1().foo()
...         MockClass2().bar()
<MagicMock name='mock.MockClass1().foo()' id='...'>
<MagicMock name='mock.MockClass2().bar()' id='...'>
>>> manager.mock_calls
[call.MockClass1(),
call.MockClass1().foo(),
call.MockClass2(),
call.MockClass2().bar()]

많은 호출이 이루어졌지만, 특정 시퀀스에만 관심이 있다면 대안은 assert_has_calls() 메서드를 사용하는 것입니다. 이것은 호출 리스트를 취합니다 (call 객체로 구성됩니다). 해당 호출 시퀀스가 mock_calls에 있으면 어서션이 성공합니다.

>>> m = MagicMock()
>>> m().foo().bar().baz()
<MagicMock name='mock().foo().bar().baz()' id='...'>
>>> m.one().two().three()
<MagicMock name='mock.one().two().three()' id='...'>
>>> calls = call.one().two().three().call_list()
>>> m.assert_has_calls(calls)

연쇄 호출 m.one().two().three()가 모의 객체에 대한 호출의 전부는 아니지만, 어서션이 여전히 성공합니다.

때로는 모의 객체에 여러 번의 호출이 있을 수 있고, 그 호출들의 일부에 대만 어서션에만 관심이 있을 수 있습니다. 순서에 신경 쓰지 않을 수도 있습니다. 이 경우 any_order=True를 assert_has_calls로 전달할 수 있습니다:

>>> m = MagicMock()
>>> m(1), m.two(2, 3), m.seven(7), m.fifty('50')
(...)
>>> calls = [call.fifty('50'), call(1), call.seven(7)]
>>> m.assert_has_calls(calls, any_order=True)

더 복잡한 인자 일치

ANY와 같은 기본 개념을 사용하여 모의 객체에 인자로 사용되는 객체에 대해 더 복잡한 어서션을 수행하도록 매처(matchers)를 구현할 수 있습니다.

기본적으로 객체 아이덴티티에 기반하여 를 기준으로 같다고 비교되는 (이것이 사용자 정의 클래스의 파이썬 기본 동작입니다) 어떤 객체가 모의 객체로 전달되기를 기대한다고 가정합시다. assert_called_with()를 사용하려면 정확히 같은 객체를 전달해야 합니다. 이 객체의 일부 어트리뷰트에만 관심이 있다면 이러한 어트리뷰트를 확인하는 매처를 만들 수 있습니다.

이 예에서 assert_called_with에 대한 ‘표준’ 호출이 충분하지 않다는 것을 볼 수 있습니다:

>>> class Foo:
...     def __init__(self, a, b):
...         self.a, self.b = a, b
...
>>> mock = Mock(return_value=None)
>>> mock(Foo(1, 2))
>>> mock.assert_called_with(Foo(1, 2))
Traceback (most recent call last):
    ...
AssertionError: expected call not found.
Expected: mock(<__main__.Foo object at 0x...>)
Actual: mock(<__main__.Foo object at 0x...>)

Foo 클래스를 위한 비교 함수는 다음과 같습니다:

>>> def compare(self, other):
...     if not type(self) == type(other):
...         return False
...     if self.a != other.a:
...         return False
...     if self.b != other.b:
...         return False
...     return True
...

그리고 동등 비교 연산에 이와 같은 비교 함수를 사용할 수 있는 매처 객체는 다음과 같습니다:

>>> class Matcher:
...     def __init__(self, compare, some_obj):
...         self.compare = compare
...         self.some_obj = some_obj
...     def __eq__(self, other):
...         return self.compare(self.some_obj, other)
...

이 모든 것을 종합하면:

>>> match_foo = Matcher(compare, Foo(1, 2))
>>> mock.assert_called_with(match_foo)

Matcher는 compare 함수와 비교하려는 Foo 객체로 인스턴스 화 됩니다. assert_called_with에서는 Matcher 동등 비교 메서드가 호출되는데, 이 메서드는 모의 객체가 호출된 객체와 우리가 매처를 만들 때 제공한 객체를 비교합니다. 일치하면 assert_called_with가 통과하고, 그렇지 않으면 AssertionError가 발생합니다:

>>> match_wrong = Matcher(compare, Foo(3, 4))
>>> mock.assert_called_with(match_wrong)
Traceback (most recent call last):
    ...
AssertionError: Expected: ((<Matcher object at 0x...>,), {})
Called with: ((<Foo object at 0x...>,), {})

약간의 조정만으로 비교 함수가 AssertionError를 직접 발생시키고 더 유용한 실패 메시지를 제공할 수 있습니다.

버전 1.5부터, 파이썬 테스트 라이브러리 PyHamcrest [https://pyhamcrest.readthedocs.io/]는 여기에서 유용할 수 있는 유사한 기능을 동등 비교 매처의 형태로 제공합니다 (hamcrest.library.integration.match_equality [https://pyhamcrest.readthedocs.io/en/release-1.8/integration/#module-hamcrest.library.integration.match_equality]).

test — Regression tests package for Python

참고

test 패키지는 파이썬 내부 용으로만 사용됩니다. 파이썬의 핵심 개발자를 위해 설명됩니다. 여기에 언급된 코드는 파이썬 릴리스 사이에 예고 없이 변경되거나 제거될 수 있어서, 파이썬의 표준 라이브러리 외부에서 이 패키지를 사용하는 것은 권장되지 않습니다.

test 패키지에는 test.support와 test.regrtest뿐만 아니라 파이썬에 대한 모든 회귀 테스트가 포함되어 있습니다. test.support는 테스트를 향상하는 데 사용되며 test.regrtest는 테스트 스위트를 구동합니다.

이름이 test_로 시작하는 test 패키지의 각 모듈은 특정 모듈이나 기능에 대한 테스트 스위트입니다. 모든 새로운 테스트는 unittest나 doctest 모듈을 사용하여 작성해야 합니다. 일부 오래된 테스트는 sys.stdout으로 인쇄된 출력을 비교하는 “전통적인” 테스트 스타일을 사용하여 작성되었습니다; 이 테스트 스타일은 폐지된 것으로 간주합니다.

더 보기

모듈 unittest

PyUnit 회귀 테스트 작성.

모듈 doctest

독스트링에 포함된 테스트.

test 패키지를 위한 단위 테스트 작성하기

unittest 모듈을 사용하는 테스트는 몇 가지 지침을 따르는 것이 좋습니다. 하나는 테스트 모듈의 이름을 test_로 시작하고 테스트 중인 모듈의 이름으로 끝나도록 짓는 것입니다. 테스트 모듈의 테스트 메서드는 test_로 시작하고 메서드가 테스트하는 내용에 대한 설명으로 끝나야 합니다. 이는 테스트 드라이버가 메서드를 테스트 메서드로 인식하기 위해 필요합니다. 또한, 메서드에 대한 독스트링이 포함되어서는 안 됩니다. 주석(가령 # Tests function returns only True or False)을 사용하여 테스트 메서드에 대한 설명을 제공해야 합니다. 이는 독스트링이 존재하면 이것이 인쇄되어 실행되는 테스트가 인쇄되지 않기 때문입니다.

기본 상용구가 자주 사용됩니다:

import unittest
from test import support

class MyTestCase1(unittest.TestCase):

    # Only use setUp() and tearDown() if necessary

    def setUp(self):
        ... code to execute in preparation for tests ...

    def tearDown(self):
        ... code to execute to clean up after tests ...

    def test_feature_one(self):
        # Test feature one.
        ... testing code ...

    def test_feature_two(self):
        # Test feature two.
        ... testing code ...

    ... more test methods ...

class MyTestCase2(unittest.TestCase):
    ... same structure as MyTestCase1 ...

... more test classes ...

if __name__ == '__main__':
    unittest.main()

이 코드 패턴을 사용하면 test.regrtest에서 자체적으로 unittest CLI를 지원하는 스크립트로나 python -m unittest CLI를 통해 테스트 스위트를 실행할 수 있습니다.

회귀 테스트의 목표는 코드를 깨려고 시도하는 것입니다. 이는 따라야 할 몇 가지 지침으로 이어집니다:

테스트 스위트는 모든 클래스, 함수 및 상수를 괴롭혀야 합니다. 여기에는 외부 세계에 제공되는 외부 API뿐만 아니라 “내부(private)” 코드도 포함됩니다.

화이트 박스 테스트 (테스트 작성 시 테스트 중인 코드 검사)가 선호됩니다. 블랙박스 테스트(게시된 사용자 인터페이스 만 테스트)는 모든 경계와 에지 케이스가 테스트 되었는지 확인하기에 충분하지 않습니다.

유효하지 않은 값을 포함하여 가능한 모든 값이 테스트 되었는지 확인하십시오. 이렇게 하면 모든 유효한 값이 받아들여질 뿐만 아니라 부적절한 값이 올바르게 처리되었는지 확인하게 됩니다.

가능한 한 많은 코드 경로를 소진하십시오. 분기가 발생하는 위치를 테스트하고 입력을 조정하여 코드에서 여러 경로가 사용되는지 확인합니다.

테스트 된 코드에 대해 발견된 버그에 대한 명시적 테스트를 추가합니다. 이렇게 하면 나중에 코드가 변경되어도 에러가 다시 발생하는지 확인합니다.

테스트 후에 정리해야 합니다 (가령 모든 임시 파일 닫고 제거하기).

테스트가 운영 체제의 특정 조건에 의존하면 테스트를 시도하기 전에 조건이 이미 존재하는지 확인하십시오.

가능한 한 적은 수의 모듈을 임포트 하고 가능한 한 빨리 수행하십시오. 이렇게 하면 테스트의 외부 종속성이 최소화되고 모듈 임포트의 부작용에 따른 비정상적인 동작이 최소화됩니다.

코드 재사용을 극대화하십시오. 때에 따라, 테스트는 사용되는 입력 유형에 따라 조금씩 달라집니다. 입력을 지정하는 클래스로 기본 테스트 클래스를 서브 클래싱하여 코드 중복을 최소화합니다:

class TestFuncAcceptsSequencesMixin:

    func = mySuperWhammyFunction

    def test_func(self):
        self.func(self.arg)

class AcceptLists(TestFuncAcceptsSequencesMixin, unittest.TestCase):
    arg = [1, 2, 3]

class AcceptStrings(TestFuncAcceptsSequencesMixin, unittest.TestCase):
    arg = 'abc'

class AcceptTuples(TestFuncAcceptsSequencesMixin, unittest.TestCase):
    arg = (1, 2, 3)

When using this pattern, remember that all classes that inherit from unittest.TestCase are run as tests. The TestFuncAcceptsSequencesMixin class in the example above does not have any data and so can’t be run by itself, thus it does not inherit from unittest.TestCase.

더 보기

테스트 주도 개발(Test Driven Development)

코드 전에 테스트를 작성하는 것에 관한 Kent Beck의 책.

명령 줄 인터페이스를 사용하여 테스트 실행하기

-m 옵션 덕분에 test 패키지를 스크립트로 실행하여 파이썬의 회귀 테스트 스위트를 구동 할 수 있습니다: python -m test. 내부적으로는 test.regrtest를 사용합니다; 이전 파이썬 버전에서 사용된 호출 python -m test.regrtest는 여전히 작동합니다. 스크립트를 단독으로 실행하면 test 패키지의 모든 회귀 테스트 실행이 자동으로 시작됩니다. 패키지에서 이름이 test_로 시작하는 모든 모듈을 찾아서, 임포트 하고, test_main() 함수가 있으면 실행하고, test_main이 없으면 unittest.TestLoader.loadTestsFromModule 을 통해 테스트를 로드하여 이를 수행합니다. 실행할 테스트 이름도 스크립트에 전달할 수 있습니다. 단일 회귀 테스트를 지정하면 (python -m test test_spam) 출력이 최소화되고 테스트의 통과나 실패 여부만 인쇄됩니다.

test를 직접 실행하면 테스트에 사용할 수 있는 리소스를 설정할 수 있습니다. -u 명령 줄 옵션을 사용하여 이 작업을 수행합니다. -u 옵션의 값으로 all을 지정하면 가능한 모든 자원을 사용할 수 있습니다: python -m test -uall. 하나를 제외한 모든 리소스가 필요한 경우 (더 흔한 경우입니다), 원하지 않는 리소스의 쉼표로 구분된 목록이 all 뒤에 나열될 수 있습니다. python -m test -uall,-audio,-largefile 명령은 audio와 largefile 리소스를 제외한 모든 리소스로 test를 실행합니다. 모든 리소스와 추가 명령 줄 옵션 목록을 보려면, python -m test -h를 실행하십시오.

회귀 테스트를 실행하는 다른 방법은 테스트가 실행되는 플랫폼에 따라 다릅니다. 유닉스에서는, 파이썬이 빌드된 최상위 디렉터리에서 make test를 실행할 수 있습니다. 윈도우에서는, PCbuild 디렉터리에서 rt.bat을 실행하면 모든 회귀 테스트가 실행됩니다.

test.support — 파이썬 테스트 스위트용 유틸리티

test.support 모듈은 파이썬의 회귀 테스트 스위트를 지원합니다.

참고

test.support는 공용 모듈이 아닙니다. 파이썬 개발자가 테스트를 작성하는 데 도움이 되도록 여기에 설명하고 있습니다. 이 모듈의 API는 릴리스 간에 하위 호환성에 대한 고려 없이 변경될 수 있습니다.

이 모듈은 다음 예외를 정의합니다:

exception test.support.TestFailed

테스트가 실패할 때 발생하는 예외. 이것은 폐지되었고 unittest 기반 테스트와 unittest.TestCase의 어서션 메서드로 대체합니다.

exception test.support.ResourceDenied

unittest.SkipTest의 서브 클래스. 리소스(가령 네트워크 연결)를 사용할 수 없을 때 발생합니다. requires() 함수에 의해 발생합니다.

test.support 모듈은 다음 상수를 정의합니다:

test.support.verbose

상세 출력이 활성화될 때 True. 실행 중인 테스트에 대한 자세한 정보가 필요할 때 확인해야 합니다. verbose는 test.regrtest에 의해 설정됩니다.

test.support.is_jython

실행 중인 인터프리터가 Jython이면 True.

test.support.is_android

시스템이 안드로이드이면 True.

test.support.unix_shell

윈도우가 아니면 셸 경로; 그렇지 않으면 None.

test.support.LOOPBACK_TIMEOUT

127.0.0.1과 같은 네트워크 로컬 루프 백 인터페이스에서 리스닝하는 네트워크 서버를 사용하는 테스트의 초 단위 제한 시간.

제한 시간은 테스트 실패를 방지 할 수 있을 만큼 깁니다: 클라이언트와 서버가 다른 스레드나 다른 프로세스에서 실행될 수 있다는 점을 고려합니다.

제한 시간은 socket.socket의 connect(), recv() 및 send() 메서드를 위해 충분히 길어야 합니다.

기본값은 5초입니다.

INTERNET_TIMEOUT도 참조하십시오.

test.support.INTERNET_TIMEOUT

Timeout in seconds for network requests going to the internet.

The timeout is short enough to prevent a test to wait for too long if the internet request is blocked for whatever reason.

일반적으로, INTERNET_TIMEOUT을 사용하는 시간 초과는 테스트를 실패로 표시해서는 안 되며, 대신 테스트를 건너뜁니다: transient_internet()을 참조하십시오.

기본값은 1분입니다.

LOOPBACK_TIMEOUT도 참조하십시오.

test.support.SHORT_TIMEOUT

테스트가 “너무 오래” 걸리면 테스트를 실패로 표시하는 초 단위 제한 시간.

제한 시간 값은 regrtest --timeout 명령 줄 옵션에 따라 다릅니다.

SHORT_TIMEOUT을 사용하는 테스트가 느린 빌드 봇에서 무작위로 실패하기 시작하면, 대신 LONG_TIMEOUT을 사용합니다.

기본값은 30초입니다.

test.support.LONG_TIMEOUT

테스트 멈춤을 감지하기 위한 초 단위 제한 시간.

가장 느린 파이썬 빌드 봇에서 테스트 실패의 위험을 줄이기에 충분히 깁니다. 테스트가 “너무 오래” 걸리면 테스트를 실패로 표시하는 데 사용해서는 안 됩니다. 제한 시간 값은 regrtest --timeout 명령 줄 옵션에 따라 다릅니다.

기본값은 5분입니다.

LOOPBACK_TIMEOUT, INTERNET_TIMEOUT 및 SHORT_TIMEOUT도 참조하십시오.

test.support.PGO

PGO에 유용하지 않은 테스트를 건너뛸 수 있을 때 설정합니다.

test.support.PIPE_MAX_SIZE

쓰기 블로킹을 일으키기 위해, 하부 OS 파이프 버퍼 크기보다 클 가능성이 높은 상수.

test.support.Py_DEBUG

True if Python was built with the Py_DEBUG macro defined, that is, if Python was built in debug mode.

Added in version 3.12.

test.support.SOCK_MAX_SIZE

쓰기 블로킹을 일으키기 위해, 하부 OS 소켓 버퍼 크기보다 클 가능성이 높은 상수.

test.support.TEST_SUPPORT_DIR

test.support를 포함하는 최상위 디렉터리로 설정합니다.

test.support.TEST_HOME_DIR

테스트 패키지의 최상위 디렉터리로 설정합니다.

test.support.TEST_DATA_DIR

테스트 패키지 내의 data 디렉터리로 설정합니다.

test.support.MAX_Py_ssize_t

대용량 메모리 테스트를 위해 sys.maxsize로 설정합니다.

test.support.max_memuse

대용량 메모리 테스트를 위한 메모리 제한으로 set_memlimit()에 의해 설정됩니다. MAX_Py_ssize_t에 의해 제한됩니다.

test.support.real_max_memuse

대용량 메모리 테스트를 위한 메모리 제한으로 set_memlimit()에 의해 설정됩니다. MAX_Py_ssize_t에 의해 제한되지 않습니다.

test.support.MISSING_C_DOCSTRINGS

Set to True if Python is built without docstrings (the WITH_DOC_STRINGS macro is not defined). See the configure --without-doc-strings option.

See also the HAVE_DOCSTRINGS variable.

test.support.HAVE_DOCSTRINGS

Set to True if function docstrings are available. See the python -OO option, which strips docstrings of functions implemented in Python.

See also the MISSING_C_DOCSTRINGS variable.

test.support.TEST_HTTP_URL

네트워크 테스트를 위한 전용 HTTP 서버의 URL을 정의합니다.

test.support.ALWAYS_EQ

모든 것과 같은 객체. 혼합형 비교를 테스트하는 데 사용됩니다.

test.support.NEVER_EQ

어떤 것과도 같지 않은 객체 (ALWAYS_EQ에도 해당합니다). 혼합형 비교를 테스트하는 데 사용됩니다.

test.support.LARGEST

모든 것보다 큰 객체 (자신은 제외하고). 혼합형 비교를 테스트하는 데 사용됩니다.

test.support.SMALLEST

모든 것보다 작은 객체 (자신은 제외하고). 혼합형 비교를 테스트하는 데 사용됩니다.

test.support 모듈은 다음 함수를 정의합니다:

test.support.busy_retry(timeout, err_msg=None, /, *, error=True)

Run the loop body until break stops the loop.

After timeout seconds, raise an AssertionError if error is true, or just stop the loop if error is false.

Example:

for _ in support.busy_retry(support.SHORT_TIMEOUT):
    if check():
        break

Example of error=False usage:

for _ in support.busy_retry(support.SHORT_TIMEOUT, error=False):
    if check():
        break
else:
    raise RuntimeError('my custom error')

test.support.sleeping_retry(timeout, err_msg=None, /, *, init_delay=0.010, max_delay=1.0, error=True)

Wait strategy that applies exponential backoff.

Run the loop body until break stops the loop. Sleep at each loop iteration, but not at the first iteration. The sleep delay is doubled at each iteration (up to max_delay seconds).

See busy_retry() documentation for the parameters usage.

Example raising an exception after SHORT_TIMEOUT seconds:

for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
    if check():
        break

Example of error=False usage:

for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False):
    if check():
        break
else:
    raise RuntimeError('my custom error')

test.support.is_resource_enabled(resource)

resource가 활성화되고 사용할 수 있으면 True를 반환합니다. 사용 가능한 리소스 목록은 test.regrtest가 테스트를 실행할 때만 설정됩니다.

test.support.python_is_optimized()

파이썬이 -O0이나 -Og로 빌드되지 않았으면 True를 반환합니다.

test.support.with_pymalloc()

Return _testcapi.WITH_PYMALLOC.

test.support.requires(resource, msg=None)

resource를 사용할 수 없으면 ResourceDenied를 발생시킵니다. msg는 ResourceDenied가 발생한다면 이에 대한 인자입니다. __name__이 '__main__'인 함수에 의해 호출되면 항상 True를 반환합니다. test.regrtest에서 테스트를 실행할 때 사용됩니다.

test.support.sortdict(dict)

정렬된 키로 dict의 repr을 반환합니다.

test.support.findfile(filename, subdir=None)

filename이라는 파일의 경로를 반환합니다. 일치하는 것이 없으면 filename이 반환됩니다. 이것은 파일의 경로일 수 있어서 실패와 같지 않습니다.

subdir 설정은 경로 디렉터리를 직접 찾는 대신 파일을 찾는 데 사용할 상대 경로를 나타냅니다.

test.support.get_pagesize()

Get size of a page in bytes.

Added in version 3.12.

test.support.setswitchinterval(interval)

sys.setswitchinterval()을 주어진 interval로 설정합니다. 시스템이 멈추는 것을 방지하기 위해 안드로이드 시스템을 위한 최소 간격을 정의합니다.

test.support.check_impl_detail(**guards)

Use this check to guard CPython’s implementation-specific tests or to run them only on the implementations guarded by the arguments. This function returns True or False depending on the host platform. Example usage:

check_impl_detail()               # Only on CPython (default).
check_impl_detail(jython=True)    # Only on Jython.
check_impl_detail(cpython=False)  # Everywhere except CPython.

test.support.set_memlimit(limit)

대용량 메모리 테스트를 위해 max_memuse와 real_max_memuse 값을 설정합니다.

test.support.record_original_stdout(stdout)

stdout의 값을 저장합니다. regrtest가 시작될 때 stdout을 잡기 위한 것입니다.

test.support.get_original_stdout()

record_original_stdout()에 의해 설정된 원래 stdout이나 설정되지 않았으면 sys.stdout을 반환합니다.

test.support.args_from_interpreter_flags()

sys.flags와 sys.warnoptions의 현재 설정을 재현하는 명령 줄 인자 리스트를 반환합니다.

test.support.optim_args_from_interpreter_flags()

sys.flags의 현재 최적화 설정을 재현하는 명령 줄 인자 리스트를 반환합니다.

test.support.captured_stdin()

test.support.captured_stdout()

test.support.captured_stderr()

명명된 스트림을 io.StringIO 객체로 일시적으로 대체하는 컨텍스트 관리자.

출력 스트림 사용 예:

with captured_stdout() as stdout, captured_stderr() as stderr:
    print("hello")
    print("error", file=sys.stderr)
assert stdout.getvalue() == "hello\n"
assert stderr.getvalue() == "error\n"

입력 스트림 사용 예:

with captured_stdin() as stdin:
    stdin.write('hello\n')
    stdin.seek(0)
    # call test code that consumes from sys.stdin
    captured = input()
self.assertEqual(captured, "hello")

test.support.disable_faulthandler()

A context manager that temporary disables faulthandler.

test.support.gc_collect()

가능한 한 많은 객체를 수거하도록 강제합니다. 이는 가비지 수거기가 적시에 할당 해제를 보장하지 않기 때문에 필요합니다. 이는 __del__ 메서드가 예상보다 늦게 호출될 수 있고 약한 참조(weakrefs)가 예상보다 오래 살아있을 수 있음을 의미합니다.

test.support.disable_gc()

A context manager that disables the garbage collector on entry. On exit, the garbage collector is restored to its prior state.

test.support.swap_attr(obj, attr, new_val)

어트리뷰트를 새 객체로 스와프하는 컨텍스트 관리자.

용법:

with swap_attr(obj, "attr", 5):
    ...

이렇게 하면 with 블록의 기간 중 obj.attr이 5로 설정되고, 블록 끝에서 이전 값이 복원됩니다. obj에 attr이 없으면, 만들어지고 블록의 끝에서 삭제됩니다.

이전 값(또는 존재하지 않으면 None)이 “as” 절의 대상(있다면)에 대입됩니다.

test.support.swap_item(obj, attr, new_val)

항목을 새 객체로 스와프하는 컨텍스트 관리자.

용법:

with swap_item(obj, "item", 5):
    ...

이렇게 하면 with 블록의 기간 중 obj["item"]이 5로 설정되고, 블록 끝에서 이전 값이 복원됩니다. obj에 item이 없으면, 만들어지고 블록의 끝에서 삭제됩니다.

이전 값(또는 존재하지 않으면 None)이 “as” 절의 대상(있다면)에 대입됩니다.

test.support.flush_std_streams()

Call the flush() method on sys.stdout and then on sys.stderr. It can be used to make sure that the logs order is consistent before writing into stderr.

Added in version 3.11.

test.support.print_warning(msg)

sys.__stderr__에 경고를 인쇄합니다. 메시지를 다음처럼 포맷합니다: f"Warning -- {msg}". msg가 여러 줄로 구성되면, 각 줄에 "Warning -- " 접두사를 추가합니다.

Added in version 3.9.

test.support.wait_process(pid, *, exitcode, timeout=None)

프로세스 pid가 완료될 때까지 기다렸다가 프로세스 종료 코드가 exitcode인지 확인합니다.

프로세스 종료 코드가 exitcode와 같지 않으면 AssertionError를 발생시킵니다.

프로세스가 timeout(기본적으로 SHORT_TIMEOUT) 초보다 오래 실행되면, 프로세스를 죽이고 AssertionError를 발생시킵니다. 제한 시간 기능은 윈도우에서 사용할 수 없습니다.

Added in version 3.9.

test.support.calcobjsize(fmt)

Return the size of the PyObject whose structure members are defined by fmt. The returned value includes the size of the Python object header and alignment.

test.support.calcvobjsize(fmt)

Return the size of the PyVarObject whose structure members are defined by fmt. The returned value includes the size of the Python object header and alignment.

test.support.checksizeof(test, o, size)

테스트 케이스 test에 대해, o의 sys.getsizeof에 GC 헤더 크기를 더한 값이 size와 같다고 어서션 합니다.

@test.support.anticipate_failure(condition)

unittest.expectedFailure()로 테스트를 조건부로 표시하는 데코레이터. 이 데코레이터를 사용하려면 관련 추적기(tracker) 이슈를 식별하는 관련 주석이 있어야 합니다.

test.support.system_must_validate_cert(f)

A decorator that skips the decorated test on TLS certification validation failures.

@test.support.run_with_locale(catstr, *locales)

다른 로케일에서 함수를 실행하기 위한 데코레이터로, 완료된 후 올바르게 재설정합니다. catstr은 문자열로 된 로케일 범주입니다 (예를 들어 "LC_ALL"). 전달된 locales는 순차적으로 시도되며, 첫 번째 유효한 로케일이 사용됩니다.

@test.support.run_with_tz(tz)

특정 시간대에서 함수를 실행하기 위한 데코레이터로, 완료된 후 올바르게 재설정합니다.

@test.support.requires_freebsd_version(*min_version)

Decorator for the minimum version when running test on FreeBSD. If the FreeBSD version is less than the minimum, the test is skipped.

@test.support.requires_linux_version(*min_version)

Decorator for the minimum version when running test on Linux. If the Linux version is less than the minimum, the test is skipped.

@test.support.requires_mac_version(*min_version)

Decorator for the minimum version when running test on macOS. If the macOS version is less than the minimum, the test is skipped.

@test.support.requires_gil_enabled

Decorator for skipping tests on the free-threaded build. If the GIL is disabled, the test is skipped.

@test.support.requires_IEEE_754

비 IEEE 754 플랫폼에서 테스트를 건너뛰는 데코레이터.

@test.support.requires_zlib

zlib가 없으면 테스트를 건너뛰는 데코레이터.

@test.support.requires_gzip

gzip이 없으면 테스트를 건너뛰는 데코레이터.

@test.support.requires_bz2

bz2가 없으면 테스트를 건너뛰는 데코레이터.

@test.support.requires_lzma

lzma가 없으면 테스트를 건너뛰는 데코레이터.

@test.support.requires_resource(resource)

resource를 사용할 수 없으면 테스트를 건너뛰는 데코레이터.

@test.support.requires_docstrings

HAVE_DOCSTRINGS일 때만 테스트를 실행하는 데코레이터.

@test.support.requires_limited_api

Decorator for only running the test if Limited C API is available.

@test.support.cpython_only

CPython에만 적용되는 테스트용 데코레이터.

@test.support.impl_detail(msg=None, **guards)

guards에 check_impl_detail()을 호출하는 데코레이터. False가 반환되면, 테스트를 건너뛰는 이유로 msg를 사용합니다.

@test.support.no_tracing

테스트 기간 중 일시적으로 추적을 해제하는 데코레이터.

@test.support.refcount_test

참조 횟수를 수반하는 테스트를 위한 데코레이터. 데코레이터는 CPython에 의해 실행되지 않으면 테스트를 실행하지 않습니다. 추적 함수로 인한 예기치 않은 참조 횟수를 방지하기 위해 테스트 기간 중 모든 추적 함수가 설정 해제됩니다.

@test.support.bigmemtest(size, memuse, dry_run=True)

bigmem 테스트를 위한 데코레이터.

size는 테스트를 위해 요청된 크기입니다 (임의의 테스트가 해석하는 단위.) memuse는 테스트 단위당 바이트 수, 또는 이의 적절한 추정치입니다. 예를 들어, 각각 4GiB인 두 개의 바이트 버퍼가 필요한 테스트는 @bigmemtest(size=_4G, memuse=2)로 데코레이트 될 수 있습니다.

size 인자는 일반적으로 데코레이트 된 테스트 메서드에 추가 인자로 전달됩니다. dry_run이 True이면, 테스트 메서드에 전달된 값이 요청된 값보다 작을 수 있습니다. dry_run이 False이면, -M가 지정되지 않은 경우 테스트가 더미 실행을 지원하지 않음을 의미합니다.

@test.support.bigaddrspacetest

Decorator for tests that fill the address space.

test.support.check_syntax_error(testcase, statement, errtext='', *, lineno=None, offset=None)

statement 컴파일을 시도하여 statement의 구문 에러를 테스트합니다. testcase는 테스트를 위한 unittest 인스턴스입니다. errtext는 발생한 SyntaxError의 문자열 표현과 일치해야 하는 정규식입니다. lineno가 None이 아니면, 예외 줄과 비교합니다. offset이 None이 아니면, 예외의 오프셋과 비교합니다.

test.support.open_urlresource(url, *args, **kw)

url을 엽니다. 열기에 실패하면, TestFailed를 발생시킵니다.

test.support.reap_children()

서브 프로세스가 시작될 때마다 test_main 끝에 이것을 사용하십시오. 이렇게 하면 여분의 자식(좀비)이 남아서 리소스를 탐하지 않도록 하고 참조 누수를 찾을 때 문제가 발생하지 않도록 할 수 있습니다.

test.support.get_attribute(obj, name)

어트리뷰트를 가져옵니다, AttributeError가 발생하면 unittest.SkipTest를 발생시킵니다.

test.support.catch_unraisable_exception()

sys.unraisablehook()를 사용하여 발생시킬 수 없는(unraisable) 예외를 포착하는 컨텍스트 관리자.

예외 값(cm.unraisable.exc_value)을 저장하면 참조 순환을 만듭니다. 컨텍스트 관리자가 탈출할 때 참조 순환이 명시적으로 끊어집니다.

객체(cm.unraisable.object)를 저장하면 파이널라이즈 중인 객체로 설정되어 있으면 되살릴 수 있습니다. 컨텍스트 관리자를 탈출하면 저장된 객체가 지워집니다.

용법:

with support.catch_unraisable_exception() as cm:
    # code creating an "unraisable exception"
    ...

    # check the unraisable exception: use cm.unraisable
    ...

# cm.unraisable attribute no longer exists at this point
# (to break a reference cycle)

Added in version 3.8.

test.support.load_package_tests(pkg_dir, loader, standard_tests, pattern)

테스트 패키지에서 사용하기 위한 unittest load_tests 프로토콜의 일반 구현. pkg_dir는 패키지의 루트 디렉터리입니다; loader, standard_tests 및 pattern은 load_tests가 기대하는 인자입니다. 간단한 경우, 테스트 패키지의 __init__.py는 다음과 같을 수 있습니다:

import os
from test.support import load_package_tests

def load_tests(*args):
    return load_package_tests(os.path.dirname(__file__), *args)

test.support.detect_api_mismatch(ref_api, other_api, *, ignore=())

ignore에 지정된 이 검사에서 무시할 정의된 항목 리스트를 제외하고, other_api에서 찾을 수 없는 ref_api의 어트리뷰트, 함수 또는 메서드 집합을 반환합니다.

기본적으로 이것은 ‘_’로 시작하는 내부(private) 어트리뷰트를 건너뛰지만, 모든 매직 메서드, 즉 ‘__’로 시작하고 끝나는 것들을 포함합니다.

Added in version 3.5.

test.support.patch(test_instance, object_to_patch, attr_name, new_value)

object_to_patch.attr_name을 new_value로 대체합니다. 또한 test_instance에 대한 정리 절차를 추가하여 object_to_patch의 attr_name을 복원합니다. attr_name은 object_to_patch의 유효한 어트리뷰트여야 합니다.

test.support.run_in_subinterp(code)

서브 인터프리터에서 code를 실행합니다. tracemalloc이 활성화되면 unittest.SkipTest를 발생시킵니다.

test.support.check_free_after_iterating(test, iter, cls, args=())

Assert instances of cls are deallocated after iterating.

test.support.missing_compiler_executable(cmd_names=[])

cmd_names에 이름이 나열된 컴파일러 실행 파일이나 cmd_names가 비어있을 때 모든 컴파일러 실행 파일이 있는지 확인하고 누락된 첫 번째 실행 파일을 반환하거나 누락된 것이 없으면 None을 반환합니다.

test.support.check__all__(test_case, module, name_of_module=None, extra=(), not_exported=())

module의 __all__ 변수에 모든 공용 이름이 포함되어 있는지 어서션 합니다.

모듈의 공용 이름(그것의 API)은 공용 이름 규칙과 일치하고 module에 정의되었는지에 따라 자동으로 감지됩니다.

name_of_module 인자는 공용 API로 감지하기 위해 API를 정의 할 수 있는 모듈을 (문자열이나 튜플로) 지정할 수 있습니다. 이에 대한 한 가지 사례는 module이 다른 모듈에서 공용 API의 일부를 임포트 할 때입니다, C 백 엔드도 가능합니다 (csv와 그것의 _csv 처럼).

The extra argument can be a set of names that wouldn’t otherwise be automatically detected as “public”, like objects without a proper __module__ attribute. If provided, it will be added to the automatically detected ones.

The not_exported argument can be a set of names that must not be treated as part of the public API even though their names indicate otherwise.

사용 예:

import bar
import foo
import unittest
from test import support

class MiscTestCase(unittest.TestCase):
    def test__all__(self):
        support.check__all__(self, foo)

class OtherTestCase(unittest.TestCase):
    def test__all__(self):
        extra = {'BAR_CONST', 'FOO_CONST'}
        not_exported = {'baz'}  # Undocumented name.
        # bar imports part of its API from _bar.
        support.check__all__(self, bar, ('bar', '_bar'),
                             extra=extra, not_exported=not_exported)

Added in version 3.6.

test.support.skip_if_broken_multiprocessing_synchronize()

Skip tests if the multiprocessing.synchronize module is missing, if there is no available semaphore implementation, or if creating a lock raises an OSError.

Added in version 3.10.

test.support.check_disallow_instantiation(test_case, tp, *args, **kwds)

Assert that type tp cannot be instantiated using args and kwds.

Added in version 3.10.

test.support.adjust_int_max_str_digits(max_digits)

This function returns a context manager that will change the global sys.set_int_max_str_digits() setting for the duration of the context to allow execution of test code that needs a different limit on the number of digits when converting between an integer and string.

Added in version 3.11.

test.support 모듈은 다음 클래스를 정의합니다:

class test.support.SuppressCrashReport

서브 프로세스를 충돌시킬 것으로 예상되는 테스트에서 충돌 대화 상자 팝업을 방지하는 데 사용되는 컨텍스트 관리자.

윈도우에서는, SetErrorMode [https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx]를 사용하여 윈도우 에러 보고 대화 상자를 비활성화합니다.

On UNIX, resource.setrlimit() is used to set resource.RLIMIT_CORE’s soft limit to 0 to prevent coredump file creation.

On both platforms, the old value is restored by __exit__().

class test.support.SaveSignals

파이썬 시그널 처리기가 등록한 시그널 처리기를 저장하고 복원하는 클래스.

save(self)

Save the signal handlers to a dictionary mapping signal numbers to the current signal handler.

restore(self)

Set the signal numbers from the save() dictionary to the saved handler.

class test.support.Matcher

matches(self, d, **kwargs)

단일 딕셔너리를 제공된 인자와 일치시키려고 합니다.

match_value(self, k, dv, v)

단일 저장된 값(dv)을 제공된 값(v)과 일치시키려고 합니다.

test.support.socket_helper — 소켓 테스트용 유틸리티

test.support.socket_helper 모듈은 소켓 테스트를 지원합니다.

Added in version 3.9.

test.support.socket_helper.IPV6_ENABLED

이 호스트에서 IPv6가 활성화되어 있으면 True로 설정하고, 그렇지 않으면 False로 설정합니다.

test.support.socket_helper.find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM)

바인딩에 적합해야 하는 미사용 포트를 반환합니다. 이는 sock 매개 변수와 같은 패밀리와 유형으로 (기본값은 AF_INET, SOCK_STREAM) 임시 소켓을 만들고, 포트를 0으로 설정하여 지정된 호스트 주소(기본값은 0.0.0.0)에 바인딩하여, OS에서 사용되지 않은 임시 포트를 도출하여 수행됩니다. 그런 다음 임시 소켓이 닫히고 삭제되고, 임시 포트가 반환됩니다.

이 메서드나 bind_port()는 테스트 기간 중 서버 소켓을 특정 포트에 바인딩해야 하는 모든 테스트에 사용해야 합니다. 어떤 것을 사용할 것인지는 호출하는 코드가 파이썬 소켓을 만드는지, 또는 사용되지 않은 포트가 생성자에서 제공되어야 하는지 또는 외부 프로그램에 전달되어야 하는지 (즉 openssl의 s_server 모드에 대한 -accept 인자)에 따라 다릅니다. 가능하면 항상 find_unused_port()보다 bind_port()를 선호하십시오. 하드 코딩된 포트를 사용하면 여러 테스트 인스턴스를 동시에 실행할 수 없게 되어 빌드 봇에 문제가 될 수 있어서 피하는 것이 좋습니다.

test.support.socket_helper.bind_port(sock, host=HOST)

소켓을 사용 가능한 포트에 바인딩하고 포트 번호를 반환합니다. 바인딩 되지 않은 포트를 사용하기 위해 임시 포트에 의존합니다. 이는 특히 빌드 봇 환경에서, 많은 테스트가 동시에 실행될 수 있어서 중요합니다. 이 메서드는 sock.family가 AF_INET이고 sock.type이 SOCK_STREAM이고, 소켓에 SO_REUSEADDR이나 SO_REUSEPORT가 설정되면 예외가 발생합니다. 테스트는 TCP/IP 소켓에 대해 이러한 소켓 옵션을 설정해서는 안 됩니다. 이러한 옵션을 설정하는 유일한 경우는 여러 UDP 소켓을 통해 멀티캐스팅을 테스트하는 것입니다.

또한, SO_EXCLUSIVEADDRUSE 소켓 옵션을 사용할 수 있으면 (즉 윈도우에서), 소켓에 설정됩니다. 이렇게 하면 다른 사람이 테스트 기간 중 우리의 호스트/포트에 바인딩하는 것을 방지할 수 있습니다.

test.support.socket_helper.bind_unix_socket(sock, addr)

Bind a Unix socket, raising unittest.SkipTest if PermissionError is raised.

@test.support.socket_helper.skip_unless_bind_unix_socket

유닉스 소켓용 bind() 기능이 필요한 테스트를 실행하기 위한 데코레이터.

test.support.socket_helper.transient_internet(resource_name, *, timeout=30.0, errnos=())

인터넷 연결과 관련된 다양한 문제가 예외로 나타날 때 ResourceDenied를 발생시키는 컨텍스트 관리자.

test.support.script_helper — 파이썬 실행 테스트용 유틸리티

test.support.script_helper 모듈은 파이썬의 스크립트 실행 테스트를 지원합니다.

test.support.script_helper.interpreter_requires_environment()

sys.executable 인터프리터를 실행하기 위해 환경 변수가 필요하면 True를 반환합니다.

assert_python*() 함수를 사용하여 격리 모드(-I)를 시작하거나 환경 없음 모드(-E) 서브 인터프리터 프로세스를 시작해야 하는 테스트를 어노테이트 하는 @unittest.skipIf()와 함께 사용하도록 설계되었습니다.

정상적인 빌드와 테스트는 이러한 상황을 만나지 않지만, 파이썬의 현재 홈 찾기 논리로 명확한 홈이 없는 인터프리터에서 표준 라이브러리 테스트 스위트를 실행하려고 할 때 발생할 수 있습니다.

PYTHONHOME 설정은 이러한 상황에서 대부분의 테스트 스위트를 실행하는 한 가지 방법입니다. PYTHONPATH나 PYTHONUSERSITE는 인터프리터가 시작될 수 있는지에 영향을 줄 수 있는 다른 공통 환경 변수입니다.

test.support.script_helper.run_python_until_end(*args, **env_vars)

서브 프로세스에서 인터프리터를 실행하기 위해 env_vars 기반 환경을 설정합니다. 값에는 __isolated, __cleanenv, __cwd 및 TERM이 포함될 수 있습니다.

버전 3.9에서 변경: 이 함수는 더는 stderr에서 공백을 제거하지 않습니다.

test.support.script_helper.assert_python_ok(*args, **env_vars)

args와 선택적 환경 변수 env_vars를 사용하여 인터프리터를 실행하면 성공(rc == 0)하고 (return code, stdout, stderr) 튜플을 반환함을 어서션 합니다.

If the __cleanenv keyword-only parameter is set, env_vars is used as a fresh environment.

Python is started in isolated mode (command line option -I), except if the __isolated keyword-only parameter is set to False.

버전 3.9에서 변경: 이 함수는 더는 stderr에서 공백을 제거하지 않습니다.

test.support.script_helper.assert_python_failure(*args, **env_vars)

args와 선택적 환경 변수 env_vars를 사용하여 인터프리터 실행하면 실패(rc != 0)하고 (return code, stdout, stderr) 튜플을 반환함을 어서션 합니다.

추가 옵션은 assert_python_ok()를 참조하십시오.

버전 3.9에서 변경: 이 함수는 더는 stderr에서 공백을 제거하지 않습니다.

test.support.script_helper.spawn_python(*args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kw)

주어진 인자로 파이썬 서브 프로세스를 실행합니다.

kw는 subprocess.Popen()에 전달할 추가 키워드 인자입니다. subprocess.Popen 객체를 반환합니다.

test.support.script_helper.kill_python(p)

완료될 때까지 주어진 subprocess.Popen 프로세스를 실행하고 stdout을 반환합니다.

test.support.script_helper.make_script(script_dir, script_basename, source, omit_suffix=False)

script_dir과 script_basename 경로에 source를 포함하는 스크립트를 만듭니다. omit_suffix가 False이면, 이름에 .py를 추가합니다. 전체 스크립트 경로를 반환합니다.

test.support.script_helper.make_zip_script(zip_dir, zip_basename, script_name, name_in_zip=None)

script_name의 파일을 포함하는 확장자가 zip인 zip 파일을 zip_dir과 zip_basename에 만듭니다. name_in_zip은 아카이브 이름입니다. (full path, full path of archive name)을 포함하는 튜플을 반환합니다.

test.support.script_helper.make_pkg(pkg_dir, init_source='')

init_source를 내용으로 하는 __init__ 파일을 포함하는 pkg_dir이라는 디렉터리를 만듭니다.

test.support.script_helper.make_zip_pkg(zip_dir, zip_basename, pkg_name, script_basename, source, depth=1, compiled=False)

빈 __init__ 파일과 source를 포함하는 파일 script_basename을 포함하는 zip 패키지 디렉터리를 zip_dir과 zip_basename 경로로 만듭니다. compiled가 True이면, 두 소스 파일이 모두 컴파일되어 zip 패키지에 추가됩니다. 전체 zip 경로와 zip 파일의 아카이브 이름의 튜플을 반환합니다.

test.support.bytecode_helper — 올바른 바이트 코드 생성 테스트를 위한 지원 도구

test.support.bytecode_helper 모듈은 바이트 코드 생성 테스트와 검사를 지원합니다.

Added in version 3.9.

모듈은 다음 클래스를 정의합니다:

class test.support.bytecode_helper.BytecodeTestCase(unittest.TestCase)

이 클래스에는 바이트 코드를 검사하기 위한 사용자 정의 어서션 메서드가 있습니다.

BytecodeTestCase.get_disassembly_as_string(co)

co의 역 어셈블리를 문자열로 반환합니다.

BytecodeTestCase.assertInBytecode(x, opname, argval=_UNSPECIFIED)

opname이 발견되면 명령어를 반환하고, 그렇지 않으면 AssertionError를 던집니다.

BytecodeTestCase.assertNotInBytecode(x, opname, argval=_UNSPECIFIED)

opname이 발견되면 AssertionError를 던집니다.

test.support.threading_helper — Utilities for threading tests

The test.support.threading_helper module provides support for threading tests.

Added in version 3.10.

test.support.threading_helper.join_thread(thread, timeout=None)

timeout 내에 thread에 조인(join)합니다. 스레드가 timeout 초 후에도 여전히 살아 있으면 AssertionError를 발생시킵니다.

@test.support.threading_helper.reap_threads

테스트가 실패하더라도 스레드를 정리하는 데코레이터.

test.support.threading_helper.start_threads(threads, unlock=None)

Context manager to start threads, which is a sequence of threads. unlock is a function called after the threads are started, even if an exception was raised; an example would be threading.Event.set(). start_threads will attempt to join the started threads upon exit.

test.support.threading_helper.threading_cleanup(*original_values)

original_values에 지정되지 않은 스레드를 정리합니다. 테스트가 백그라운드에서 실행 중인 스레드를 남겨두면 경고를 내도록 설계되었습니다.

test.support.threading_helper.threading_setup()

현재 스레드 수와 매달린(dangling) 스레드의 복사본을 반환합니다.

test.support.threading_helper.wait_threads_exit(timeout=None)

with 문에서 만들어진 모든 스레드가 종료할 때까지 대기하는 컨텍스트 관리자.

test.support.threading_helper.catch_threading_exception()

threading.excepthook()을 사용하여 threading.Thread 예외를 포착하는 컨텍스트 관리자.

Attributes set when an exception is caught:

exc_type

exc_value

exc_traceback

thread

threading.excepthook() 설명서를 참조하십시오.

이러한 어트리뷰트들은 컨텍스트 관리자 탈출 시에 삭제됩니다.

용법:

with threading_helper.catch_threading_exception() as cm:
    # code spawning a thread which raises an exception
    ...

    # check the thread exception, use cm attributes:
    # exc_type, exc_value, exc_traceback, thread
    ...

# exc_type, exc_value, exc_traceback, thread attributes of cm no longer
# exists at this point
# (to avoid reference cycles)

Added in version 3.8.

test.support.os_helper — Utilities for os tests

The test.support.os_helper module provides support for os tests.

Added in version 3.10.

test.support.os_helper.FS_NONASCII

os.fsencode()로 인코딩 할 수 있는 비 ASCII 문자.

test.support.os_helper.SAVEDCWD

os.getcwd()로 설정합니다.

test.support.os_helper.TESTFN

임시 파일의 이름으로 사용하기에 안전한 이름으로 설정합니다. 만들어진 모든 임시 파일은 닫히고 언 링크(제거) 되어야 합니다.

test.support.os_helper.TESTFN_NONASCII

Set to a filename containing the FS_NONASCII character, if it exists. This guarantees that if the filename exists, it can be encoded and decoded with the default filesystem encoding. This allows tests that require a non-ASCII filename to be easily skipped on platforms where they can’t work.

test.support.os_helper.TESTFN_UNENCODABLE

엄격(strict) 모드에서 파일 시스템 인코딩으로 인코딩할 수 없는 파일명(str 형)으로 설정합니다. 이러한 파일명을 생성할 수 없으면 None일 수 있습니다.

test.support.os_helper.TESTFN_UNDECODABLE

엄격(strict) 모드에서 파일 시스템 인코딩으로 디코딩할 수 없는 파일명(bytes 형)으로 설정합니다. 이러한 파일명을 생성할 수 없으면 None일 수 있습니다.

test.support.os_helper.TESTFN_UNICODE

임시 파일을 위한 비 ASCII 이름으로 설정합니다.

class test.support.os_helper.EnvironmentVarGuard

환경 변수를 임시로 설정하거나 설정 해제하는 데 사용되는 클래스. 인스턴스는 컨텍스트 관리자로 사용할 수 있으며 하부 os.environ을 조회/수정하기 위한 완전한 딕셔너리 인터페이스를 가질 수 있습니다. 컨텍스트 관리자를 탈출하면 이 인스턴스를 통해 수행된 환경 변수에 대한 모든 변경 사항이 되돌려집니다.

버전 3.1에서 변경: 딕셔너리 인터페이스가 추가되었습니다.

class test.support.os_helper.FakePath(path)

Simple path-like object. It implements the __fspath__() method which just returns the path argument. If path is an exception, it will be raised in __fspath__().

EnvironmentVarGuard.set(envvar, value)

일시적으로 환경 변수 envvar를 value 값으로 설정합니다.

EnvironmentVarGuard.unset(envvar)

일시적으로 환경 변수 envvar를 설정 해제합니다.

test.support.os_helper.can_symlink()

OS가 심볼릭 링크를 지원하면 True를, 그렇지 않으면 False를 반환합니다.

test.support.os_helper.can_xattr()

OS가 xattr을 지원하면 True를, 그렇지 않으면 False를 반환합니다.

test.support.os_helper.change_cwd(path, quiet=False)

현재 작업 디렉터리를 path로 일시적으로 변경하고 그 디렉터리를 산출하는 컨텍스트 관리자.

quiet가 False이면, 컨텍스트 관리자는 에러 시 예외를 발생시킵니다. 그렇지 않으면, 경고만 발행하고 현재 작업 디렉터리를 같게 유지합니다.

test.support.os_helper.create_empty_file(filename)

filename으로 빈 파일을 만듭니다. 이미 있으면, 자릅니다.

test.support.os_helper.fd_count()

열린 파일 기술자의 수를 셉니다.

test.support.os_helper.fs_is_case_insensitive(directory)

directory의 파일 시스템이 대소 문자를 구분하지 않으면 True를 반환합니다.

test.support.os_helper.make_bad_fd()

임시 파일을 여닫아서 잘못된 파일 기술자를 만든 다음, 그 기술자를 반환합니다.

test.support.os_helper.rmdir(filename)

Call os.rmdir() on filename. On Windows platforms, this is wrapped with a wait loop that checks for the existence of the file, which is needed due to antivirus programs that can hold files open and prevent deletion.

test.support.os_helper.rmtree(path)

Call shutil.rmtree() on path or call os.lstat() and os.rmdir() to remove a path and its contents. As with rmdir(), on Windows platforms this is wrapped with a wait loop that checks for the existence of the files.

@test.support.os_helper.skip_unless_symlink

심볼릭 링크 지원이 필요한 테스트를 실행하기 위한 데코레이터.

@test.support.os_helper.skip_unless_xattr

xattr 지원이 필요한 테스트를 실행하기 위한 데코레이터.

test.support.os_helper.temp_cwd(name='tempcwd', quiet=False)

임시로 새 디렉터리를 만들고 현재 작업 디렉터리(CWD)를 변경하는 컨텍스트 관리자.

컨텍스트 관리자는 현재 작업 디렉터리를 임시로 변경하기 전에 이름이 name인 임시 디렉터리를 현재 디렉터리에 만듭니다. name이 None이면, 임시 디렉터리는 tempfile.mkdtemp()를 사용하여 만들어집니다.

quiet가 False이고 만들 수 없거나 CWD를 변경할 수 없으면, 에러가 발생합니다. 그렇지 않으면, 경고만 발생하고 원래 CWD가 사용됩니다.

test.support.os_helper.temp_dir(path=None, quiet=False)

path에 임시 디렉터리를 만들고 그 디렉터리를 산출하는 컨텍스트 관리자.

path가 None이면, 임시 디렉터리는 tempfile.mkdtemp()를 사용하여 만들어집니다. quiet가 False이면, 컨텍스트 관리자는 에러 시 예외를 발생시킵니다. 그렇지 않으면, path가 지정되고 만들 수 없으면, 경고만 발행됩니다.

test.support.os_helper.temp_umask(umask)

프로세스 umask를 임시로 설정하는 컨텍스트 관리자.

test.support.os_helper.unlink(filename)

Call os.unlink() on filename. As with rmdir(), on Windows platforms, this is wrapped with a wait loop that checks for the existence of the file.

test.support.import_helper — Utilities for import tests

The test.support.import_helper module provides support for import tests.

Added in version 3.10.

test.support.import_helper.forget(module_name)

sys.modules에서 module_name이라는 모듈을 제거하고 모듈의 바이트 컴파일된 파일을 삭제합니다.

test.support.import_helper.import_fresh_module(name, fresh=(), blocked=(), deprecated=False)

이 함수는 임포트 전에 sys.modules에서 명명된 모듈을 제거하여 명명된 파이썬 모듈의 새 복사본을 임포트하고 반환합니다. reload()와 달리, 원래 모듈은 이 연산의 영향을 받지 않습니다.

fresh는 임포트를 수행하기 전에 sys.modules 캐시에서 함께 제거되는 추가 모듈 이름의 이터러블입니다.

blocked는 임포트 하는 동안 모듈 캐시에서 None으로 대체되는 모듈 이름의 이터러블로, 임포트 하려고 시도하면 ImportError가 발생하도록 합니다.

명명된 모듈과 fresh와 blocked 매개 변수에 명명된 모든 모듈은 임포트를 시작하기 전에 보관되고 새 임포트가 완료되면 sys.modules에 다시 삽입됩니다.

deprecated가 True이면 이 임포트 중에 모듈과 패키지 폐지 메시지가 억제됩니다.

이 함수는 명명된 모듈을 임포트 할 수 없으면 ImportError를 발생시킵니다.

사용 예:

# Get copies of the warnings module for testing without affecting the
# version being used by the rest of the test suite. One copy uses the
# C implementation, the other is forced to use the pure Python fallback
# implementation
py_warnings = import_fresh_module('warnings', blocked=['_warnings'])
c_warnings = import_fresh_module('warnings', fresh=['_warnings'])

Added in version 3.1.

test.support.import_helper.import_module(name, deprecated=False, *, required_on=())

이 함수는 명명된 모듈을 임포트하고 반환합니다. 일반 임포트와 달리, 이 함수는 모듈을 임포트할 수 없으면 unittest.SkipTest를 발생시킵니다.

deprecated가 True이면 이 임포트 중에 모듈과 패키지 폐지 메시지가 억제됩니다. 모듈이 한 플랫폼에서는 필수지만, 다른 곳에서는 선택적이면, required_on을 sys.platform과 비교할 플랫폼 접두사의 이터러블로 설정합니다.

Added in version 3.1.

test.support.import_helper.modules_setup()

sys.modules의 복사본을 반환합니다.

test.support.import_helper.modules_cleanup(oldmodules)

내부 캐시를 보존하기 위해 oldmodules와 encodings를 제외한 모듈들을 제거합니다.

test.support.import_helper.unload(name)

sys.modules에서 name을 삭제합니다.

test.support.import_helper.make_legacy_pyc(source)

PEP 3147 [https://peps.python.org/pep-3147/]/PEP 488 [https://peps.python.org/pep-0488/] pyc 파일을 레거시 pyc 위치로 옮기고 레거시 pyc 파일에 대한 파일 시스템 경로를 반환합니다. source 값은 소스 파일에 대한 파일 시스템 경로입니다. 반드시 존재할 필요는 없지만, PEP 3147/488 pyc 파일이 있어야 합니다.

class test.support.import_helper.CleanImport(*module_names)

A context manager to force import to return a new module reference. This is useful for testing module-level behaviors, such as the emission of a DeprecationWarning on import. Example usage:

with CleanImport('foo'):
    importlib.import_module('foo')  # New reference.

class test.support.import_helper.DirsOnSysPath(*paths)

A context manager to temporarily add directories to sys.path.

이렇게 하면 sys.path의 복사본이 만들어지고, 위치 인자로 지정된 모든 디렉터리를 추가한 다음, 컨텍스트가 끝나면 sys.path를 복사된 설정으로 되돌립니다.

객체 교체를 포함하여, 컨텍스트 관리자 본문의 모든 sys.path 수정 사항은 블록 끝에서 되돌려짐에 유의하십시오.

test.support.warnings_helper — Utilities for warnings tests

The test.support.warnings_helper module provides support for warnings tests.

Added in version 3.10.

test.support.warnings_helper.ignore_warnings(*, category)

Suppress warnings that are instances of category, which must be Warning or a subclass. Roughly equivalent to warnings.catch_warnings() with warnings.simplefilter('ignore', category=category). For example:

@warning_helper.ignore_warnings(category=DeprecationWarning)
def test_suppress_warning():
    # do something

Added in version 3.8.

test.support.warnings_helper.check_no_resource_warning(testcase)

ResourceWarning이 발생하지 않았는지 확인하는 컨텍스트 관리자. 컨텍스트 관리자가 끝나기 전에 ResourceWarning을 방출할 수 있는 객체를 제거해야 합니다.

test.support.warnings_helper.check_syntax_warning(testcase, statement, errtext='', *, lineno=1, offset=None)

statement 컴파일을 시도하여 statement에서 구문 경고를 테스트합니다. SyntaxWarning이 한 번만 방출되고, 에러로 바꿀 때 SyntaxError로 변환되는지도 테스트합니다. testcase는 테스트를 위한 unittest 인스턴스입니다. errtext는 방출된 SyntaxWarning과 발생한 SyntaxError의 문자열 표현과 일치해야 하는 정규식입니다. lineno가 None이 아니면 경고와 예외 줄과 비교합니다. offset이 None이 아니면, 예외 오프셋과 비교합니다.

Added in version 3.8.

test.support.warnings_helper.check_warnings(*filters, quiet=True)

A convenience wrapper for warnings.catch_warnings() that makes it easier to test that a warning was correctly raised. It is approximately equivalent to calling warnings.catch_warnings(record=True) with warnings.simplefilter() set to always and with the option to automatically validate the results that are recorded.

check_warnings는 위치 인자로 ("message regexp", WarningCategory) 형식의 2-튜플을 받습니다. 하나 이상의 filters가 제공되거나, 선택적 키워드 인자 quiet가 False이면, 경고가 예상대로인지 확인합니다: 지정된 각 필터는 둘러싸인 코드에서 발생한 경고 중 적어도 하나와 일치해야 합니다. 그렇지 않으면 테스트가 실패합니다. 지정된 필터와 일치하지 않는 경고가 발생하면 테스트가 실패합니다. 첫 번째 검사를 비활성화하려면, quiet를 True로 설정합니다.

인자가 지정되지 않으면, 기본값은 다음과 같습니다:

check_warnings(("", Warning), quiet=True)

이 경우 모든 경고가 포착되고 에러가 발생하지 않습니다.

컨텍스트 관리자에 진입하면, WarningRecorder 인스턴스가 반환됩니다. catch_warnings()의 하부 경고 리스트는 레코더 객체의 warnings 어트리뷰트를 통해 사용할 수 있습니다. 편의상, 가장 최근의 경고를 나타내는 객체의 어트리뷰트는 레코더 객체를 통해 직접 액세스 할 수도 있습니다 (아래 예를 참조하십시오). 경고가 발생하지 않으면, 객체에서 예상되는 경고를 나타내는 어트리뷰트는 None을 반환합니다.

레코더 객체에는 경고 리스트를 지우는 reset() 메서드도 있습니다.

컨텍스트 관리자는 다음과 같이 사용되도록 설계되었습니다:

with check_warnings(("assertion is always true", SyntaxWarning),
                    ("", UserWarning)):
    exec('assert(False, "Hey!")')
    warnings.warn(UserWarning("Hide me!"))

이 경우 경고가 발생하지 않았거나, 다른 경고가 발생하면, check_warnings()는 에러를 발생시킵니다.

테스트에서 경고가 발생했는지를 확인하는 것만이 아니라, 경고를 더 깊이 조사해야 할 때, 다음과 같은 코드를 사용할 수 있습니다:

with check_warnings(quiet=True) as w:
    warnings.warn("foo")
    assert str(w.args[0]) == "foo"
    warnings.warn("bar")
    assert str(w.args[0]) == "bar"
    assert str(w.warnings[0].args[0]) == "foo"
    assert str(w.warnings[1].args[0]) == "bar"
    w.reset()
    assert len(w.warnings) == 0

여기에서 모든 경고가 포착되고, 테스트 코드는 포착된 경고를 직접 테스트합니다.

버전 3.2에서 변경: 새로운 선택적 인자 filters와 quiet.

class test.support.warnings_helper.WarningsRecorder

단위 테스트에 대한 경고를 기록하는 데 사용되는 클래스. 자세한 내용은 위의 check_warnings() 설명서를 참조하십시오.

디버깅과 프로파일링

이 라이브러리들은 파이썬 개발을 돕습니다: 디버거를 사용하면 코드를 단계별로 실행하고, 스택 프레임을 분석하고, 중단 점을 설정할 수 있으며, 프로파일러는 코드를 실행하고, 프로그램의 병목 지점을 식별할 수 있도록 실행 시간을 자세하게 분석합니다. 감사 이벤트는 이것이 없다면 침입적인 디버깅이나 패치가 필요한 실행 시간 동작에 대한 가시성을 제공합니다.

감사 이벤트 표

bdb — Debugger framework

BdbQuit

Breakpoint

deleteMe()

enable()

disable()

bpformat()

bpprint()

file

line

temporary

cond

funcname

enabled

bpbynumber

bplist

ignore

hits

Bdb

canonic()

reset()

trace_dispatch()

dispatch_line()

dispatch_call()

dispatch_return()

dispatch_exception()

is_skipped_line()

stop_here()

break_here()

break_anywhere()

user_call()

user_line()

user_return()

user_exception()

do_clear()

set_step()

set_next()

set_return()

set_until()

set_trace()

set_continue()

set_quit()

set_break()

clear_break()

clear_bpbynumber()

clear_all_file_breaks()

clear_all_breaks()

get_bpbynumber()

get_break()

get_breaks()

get_file_breaks()

get_all_breaks()

get_stack()

format_stack_entry()

run()

runeval()

runctx()

runcall()

checkfuncname()

effective()

set_trace()

faulthandler — Dump the Python traceback

트레이스백 덤프하기

dump_traceback()

결함 처리기 상태

enable()

disable()

is_enabled()

시간 초과 후에 트레이스백 덤프하기

dump_traceback_later()

cancel_dump_traceback_later()

사용자 시그널에 트레이스백 덤프하기

register()

unregister()

파일 기술자 관련 문제

예제

pdb — 파이썬 디버거

run()

runeval()

runcall()

set_trace()

post_mortem()

pm()

Pdb

run()

runeval()

runcall()

set_trace()

디버거 명령들

파이썬 프로파일러

프로파일러 소개

즉석 사용자 설명서

profile과 cProfile 모듈 레퍼런스

run()

runctx()

Profile

enable()

disable()

create_stats()

print_stats()

dump_stats()

run()

runctx()

runcall()

Stats 클래스

Stats

strip_dirs()

add()

dump_stats()

sort_stats()

reverse_order()

print_stats()

print_callers()

print_callees()

get_stats_profile()

결정론적 프로파일링이란 무엇입니까?

한계

보정

사용자 정의 타이머 사용하기

timeit — Measure execution time of small code snippets

기본 예제

파이썬 인터페이스

timeit()

repeat()

default_timer()

Timer

timeit()

autorange()

repeat()

print_exc()

명령 줄 인터페이스

예제

trace — Trace or track Python statement execution

명령 줄 사용법

주요 옵션

수정자

필터

프로그래밍 인터페이스

Trace

run()

runctx()

runfunc()

results()

CoverageResults

update()

write_results()

tracemalloc — Trace memory allocations

예

상위 10개 표시

차이 계산

메모리 블록의 트레이스백 얻기

예쁜 탑(top)

모든 추적한 메모리 블록의 현재 및 최대 크기를 기록

API

함수

clear_traces()

get_object_traceback()

get_traceback_limit()

get_traced_memory()

reset_peak()

get_tracemalloc_memory()

is_tracing()

start()

stop()

take_snapshot()

DomainFilter

DomainFilter

inclusive

domain

Filter

Filter

domain

inclusive

lineno

filename_pattern

all_frames

Frame

Frame

filename

lineno

Snapshot

Snapshot

compare_to()

dump()

filter_traces()

load()

statistics()

traceback_limit

traces

Statistic

Statistic

count

size

traceback

StatisticDiff

StatisticDiff

count

count_diff

size

size_diff

traceback

Trace

Trace

domain

size

traceback

Traceback

Traceback

total_nframe

format()

감사 이벤트 표

This table contains all events raised by sys.audit() or PySys_Audit() calls throughout the CPython runtime and the standard library. These calls were added in 3.8 or later (see PEP 578 [https://peps.python.org/pep-0578/]).

이 이벤트 처리에 대한 정보는 sys.addaudithook()과 PySys_AddAuditHook()을 참조하십시오.

CPython 구현 상세: 이 표는 CPython 설명서로부터 생성되며, 다른 구현에서 발생하는 이벤트를 나타내지 않을 수 있습니다. 실제 발생한 이벤트에 대해서는 여러분의 런타임 관련 설명서를 참조하십시오.

Audit event

Arguments

References

_thread.start_new_thread

function, args, kwargs

[1]

array.__new__

typecode, initializer

[1]

builtins.breakpoint

breakpointhook

[1]

builtins.id

id

[1]

builtins.input

prompt

[1]

builtins.input/result

result

[1]

code.__new__

code, filename, name, argcount, posonlyargcount, kwonlyargcount, nlocals, stacksize, flags

[1]

compile

source, filename

[1]

cpython.PyInterpreterState_Clear

[1]

cpython.PyInterpreterState_New

[1]

cpython._PySys_ClearAuditHooks

[1]

cpython.run_command

command

[1]

cpython.run_file

filename

[1]

cpython.run_interactivehook

hook

[1]

cpython.run_module

module-name

[1]

cpython.run_startup

filename

[1]

cpython.run_stdin

[1][2][3]

ctypes.addressof

obj

[1]

ctypes.call_function

func_pointer, arguments

[1]

ctypes.cdata

address

[1]

ctypes.cdata/buffer

pointer, size, offset

[1][2]

ctypes.create_string_buffer

init, size

[1]

ctypes.create_unicode_buffer

init, size

[1]

ctypes.dlopen

name

[1]

ctypes.dlsym

library, name

[1]

ctypes.dlsym/handle

handle, name

[1]

ctypes.get_errno

[1]

ctypes.get_last_error

[1]

ctypes.set_errno

errno

[1]

ctypes.set_exception

code

[1]

ctypes.set_last_error

error

[1]

ctypes.string_at

ptr, size

[1]

ctypes.wstring_at

ptr, size

[1]

ensurepip.bootstrap

root

[1]

exec

code_object

[1][2]

fcntl.fcntl

fd, cmd, arg

[1]

fcntl.flock

fd, operation

[1]

fcntl.ioctl

fd, request, arg

[1]

fcntl.lockf

fd, cmd, len, start, whence

[1]

ftplib.connect

self, host, port

[1]

ftplib.sendcmd

self, cmd

[1][2]

function.__new__

code

[1]

gc.get_objects

generation

[1]

gc.get_referents

objs

[1]

gc.get_referrers

objs

[1]

glob.glob

pathname, recursive

[1][2]

glob.glob/2

pathname, recursive, root_dir, dir_fd

[1][2]

http.client.connect

self, host, port

[1]

http.client.send

self, data

[1]

imaplib.open

self, host, port

[1]

imaplib.send

self, data

[1]

import

module, filename, sys.path, sys.meta_path, sys.path_hooks

[1]

marshal.dumps

value, version

[1]

marshal.load

[1]

marshal.loads

bytes

[1]

mmap.__new__

fileno, length, access, offset

[1]

msvcrt.get_osfhandle

fd

[1]

msvcrt.locking

fd, mode, nbytes

[1]

msvcrt.open_osfhandle

handle, flags

[1]

object.__delattr__

obj, name

[1]

object.__getattr__

obj, name

[1]

object.__setattr__

obj, name, value

[1]

open

path, mode, flags

[1][2][3]

os.add_dll_directory

path

[1]

os.chdir

path

[1][2]

os.chflags

path, flags

[1][2]

os.chmod

path, mode, dir_fd

[1][2][3]

os.chown

path, uid, gid, dir_fd

[1][2][3]

os.exec

path, args, env

[1]

os.fork

[1]

os.forkpty

[1]

os.fwalk

top, topdown, onerror, follow_symlinks, dir_fd

[1]

os.getxattr

path, attribute

[1]

os.kill

pid, sig

[1]

os.killpg

pgid, sig

[1]

os.link

src, dst, src_dir_fd, dst_dir_fd

[1]

os.listdir

path

[1]

os.listdrives

[1]

os.listmounts

volume

[1]

os.listvolumes

[1]

os.listxattr

path

[1]

os.lockf

fd, cmd, len

[1]

os.mkdir

path, mode, dir_fd

[1][2]

os.posix_spawn

path, argv, env

[1][2]

os.putenv

key, value

[1]

os.remove

path, dir_fd

[1][2][3]

os.removexattr

path, attribute

[1]

os.rename

src, dst, src_dir_fd, dst_dir_fd

[1][2][3]

os.rmdir

path, dir_fd

[1]

os.scandir

path

[1]

os.setxattr

path, attribute, value, flags

[1]

os.spawn

mode, path, args, env

[1]

os.startfile

path, operation

[1]

os.startfile/2

path, operation, arguments, cwd, show_cmd

[1]

os.symlink

src, dst, dir_fd

[1]

os.system

command

[1]

os.truncate

fd, length

[1][2]

os.unsetenv

key

[1]

os.utime

path, times, ns, dir_fd

[1]

os.walk

top, topdown, onerror, followlinks

[1]

pathlib.Path.glob

self, pattern

[1]

pathlib.Path.rglob

self, pattern

[1]

pdb.Pdb

[1]

pickle.find_class

module, name

[1]

poplib.connect

self, host, port

[1][2]

poplib.putline

self, line

[1][2]

pty.spawn

argv

[1]

resource.prlimit

pid, resource, limits

[1]

resource.setrlimit

resource, limits

[1]

setopencodehook

[1]

shutil.chown

path, user, group

[1]

shutil.copyfile

src, dst

[1][2][3]

shutil.copymode

src, dst

[1][2]

shutil.copystat

src, dst

[1][2]

shutil.copytree

src, dst

[1]

shutil.make_archive

base_name, format, root_dir, base_dir

[1]

shutil.move

src, dst

[1]

shutil.rmtree

path, dir_fd

[1]

shutil.unpack_archive

filename, extract_dir, format

[1]

signal.pthread_kill

thread_id, signalnum

[1]

smtplib.connect

self, host, port

[1]

smtplib.send

self, data

[1]

socket.__new__

self, family, type, protocol

[1]

socket.bind

self, address

[1]

socket.connect

self, address

[1][2]

socket.getaddrinfo

host, port, family, type, protocol

[1]

socket.gethostbyaddr

ip_address

[1]

socket.gethostbyname

hostname

[1][2]

socket.gethostname

[1]

socket.getnameinfo

sockaddr

[1]

socket.getservbyname

servicename, protocolname

[1]

socket.getservbyport

port, protocolname

[1]

socket.sendmsg

self, address

[1]

socket.sendto

self, address

[1]

socket.sethostname

name

[1]

sqlite3.connect

database

[1]

sqlite3.connect/handle

connection_handle

[1]

sqlite3.enable_load_extension

connection, enabled

[1]

sqlite3.load_extension

connection, path

[1]

subprocess.Popen

executable, args, cwd, env

[1]

sys._current_exceptions

[1]

sys._current_frames

[1]

sys._getframe

frame

[1]

sys._getframemodulename

depth

[1]

sys.addaudithook

[1][2]

sys.excepthook

hook, type, value, traceback

[1]

sys.set_asyncgen_hooks_finalizer

[1]

sys.set_asyncgen_hooks_firstiter

[1]

sys.setprofile

[1]

sys.settrace

[1]

sys.unraisablehook

hook, unraisable

[1]

syslog.closelog

[1]

syslog.openlog

ident, logoption, facility

[1]

syslog.setlogmask

maskpri

[1]

syslog.syslog

priority, message

[1]

tempfile.mkdtemp

fullpath

[1][2]

tempfile.mkstemp

fullpath

[1][2][3]

time.sleep

secs

[1]

urllib.Request

fullurl, data, headers, method

[1]

webbrowser.open

url

[1]

winreg.ConnectRegistry

computer_name, key

[1]

winreg.CreateKey

key, sub_key, access

[1][2]

winreg.DeleteKey

key, sub_key, access

[1][2]

winreg.DeleteValue

key, value

[1]

winreg.DisableReflectionKey

key

[1]

winreg.EnableReflectionKey

key

[1]

winreg.EnumKey

key, index

[1]

winreg.EnumValue

key, index

[1]

winreg.ExpandEnvironmentStrings

str

[1]

winreg.LoadKey

key, sub_key, file_name

[1]

winreg.OpenKey

key, sub_key, access

[1]

winreg.OpenKey/result

key

[1][2][3]

winreg.PyHKEY.Detach

key

[1]

winreg.QueryInfoKey

key

[1]

winreg.QueryReflectionKey

key

[1]

winreg.QueryValue

key, sub_key, value_name

[1][2]

winreg.SaveKey

key, file_name

[1]

winreg.SetValue

key, sub_key, type, value

[1][2]

다음 이벤트는 내부적으로 발생하며 어떤 CPython의 공개 API에도 해당하지 않습니다:

감사 이벤트

인자

_winapi.CreateFile

file_name, desired_access, share_mode, creation_disposition, flags_and_attributes

_winapi.CreateJunction

src_path, dst_path

_winapi.CreateNamedPipe

name, open_mode, pipe_mode

_winapi.CreatePipe

_winapi.CreateProcess

application_name, command_line, current_directory

_winapi.OpenProcess

process_id, desired_access

_winapi.TerminateProcess

handle, exit_code

ctypes.PyObj_FromPtr

obj

bdb — Debugger framework

소스 코드: Lib/bdb.py [https://github.com/python/cpython/tree/main/Lib/bdb.py]

bdb 모듈은 중단점 설정이나 디버거를 통한 실행 관리와 같은 기본 디버거 기능을 처리합니다.

다음 예외가 정의됩니다:

exception bdb.BdbQuit

디버거를 종료하기 위해 Bdb 클래스가 발생시키는 예외.

bdb 모듈은 또한 두 가지 클래스를 정의합니다:

class bdb.Breakpoint(self, file, line, temporary=False, cond=None, funcname=None)

이 클래스는 임시 중단점, 무시 카운트, 비활성화와 (재) 활성화 및 조건을 구현합니다.

중단점은 bpbynumber라는 리스트를 통해 번호로, bplist를 통해 (file, line) 쌍으로 인덱싱됩니다. 전자는 Breakpoint 클래스의 단일 인스턴스를 가리킵니다. 후자는 줄당 하나 이상의 중단점이 있을 수 있어서 이러한 인스턴스의 리스트를 가리킵니다.

When creating a breakpoint, its associated file name should be in canonical form. If a funcname is defined, a breakpoint hit will be counted when the first line of that function is executed. A conditional breakpoint always counts a hit.

Breakpoint 인스턴스에는 다음과 같은 메서드가 있습니다:

deleteMe()

file/line과 관련된 리스트에서 중단점을 삭제합니다. 해당 위치의 마지막 중단점이면, file/line의 항목도 삭제합니다.

enable()

중단점을 활성화된 것으로 표시합니다.

disable()

중단점을 비활성화된 것으로 표시합니다.

bpformat()

멋지게 포맷된, 중단점에 대한 모든 정보가 포함된 문자열을 반환합니다:

Breakpoint number.

Temporary status (del or keep).

File/line position.

Break condition.

Number of times to ignore.

Number of times hit.

Added in version 3.2.

bpprint(out=None)

bpformat()의 출력을 파일 out, 또는 None이면 표준 출력으로 인쇄합니다.

Breakpoint instances have the following attributes:

file

File name of the Breakpoint.

line

Line number of the Breakpoint within file.

temporary

True if a Breakpoint at (file, line) is temporary.

cond

Condition for evaluating a Breakpoint at (file, line).

funcname

Function name that defines whether a Breakpoint is hit upon entering the function.

enabled

True if Breakpoint is enabled.

bpbynumber

Numeric index for a single instance of a Breakpoint.

bplist

Dictionary of Breakpoint instances indexed by (file, line) tuples.

ignore

Number of times to ignore a Breakpoint.

hits

Count of the number of times a Breakpoint has been hit.

class bdb.Bdb(skip=None)

Bdb 클래스는 범용 파이썬 디버거 베이스 클래스 역할을 합니다.

이 클래스는 추적 기능의 세부 사항을 처리합니다; 파생 클래스는 사용자 상호 작용을 구현해야 합니다. 표준 디버거 클래스 (pdb.Pdb)가 예입니다.

skip 인자는, 주어지면, glob 스타일 모듈 이름 패턴의 이터러블 이어야 합니다. 디버거는 이러한 패턴 중 하나와 일치하는 모듈에서 시작되는 프레임으로 들어가지 않습니다. 프레임을 특정 모듈에서 시작된 것으로 간주하는지는 프레임 전역의 __name__에 의해 결정됩니다.

버전 3.1에서 변경: Added the skip parameter.

Bdb의 다음 메서드는 일반적으로 재정의할 필요가 없습니다.

canonic(filename)

Return canonical form of filename.

For real file names, the canonical form is an operating-system-dependent, case-normalized absolute path. A filename with angle brackets, such as "<stdin>" generated in interactive mode, is returned unchanged.

reset()

Set the botframe, stopframe, returnframe and quitting attributes with values ready to start debugging.

trace_dispatch(frame, event, arg)

이 함수는 디버그되는 프레임의 추적 함수(trace function)로 설치됩니다. 반환 값은 새로운 추적 함수(대부분 자체)입니다.

기본 구현은 실행되려고 하는 (문자열로 전달된) 이벤트의 유형에 따라 프레임을 디스패치 하는 방법을 결정합니다. event는 다음 중 하나일 수 있습니다:

"line": 새로운 코드 줄이 실행되려고 합니다.

"call": 함수가 호출되거나, 다른 코드 블록에 진입하려고 합니다.

"return": 함수나 다른 코드 블록이 반환하려고 합니다.

"exception": 예외가 발생했습니다.

"c_call": C 함수가 호출되려고 합니다.

"c_return": C 함수가 반환했습니다.

"c_exception": C 함수가 예외를 발생시켰습니다.

파이썬 이벤트의 경우, 특수 함수(아래를 참조하세요)가 호출됩니다. C 이벤트의 경우, 아무런 액션도 취하지 않습니다.

arg 매개 변수는 앞의 이벤트에 따라 다릅니다.

추적 함수에 대한 자세한 내용은 sys.settrace() 설명서를 참조하십시오. 코드와 프레임 객체에 대한 자세한 내용은 표준형 계층을 참조하십시오.

dispatch_line(frame)

If the debugger should stop on the current line, invoke the user_line() method (which should be overridden in subclasses). Raise a BdbQuit exception if the quitting flag is set (which can be set from user_line()). Return a reference to the trace_dispatch() method for further tracing in that scope.

dispatch_call(frame, arg)

If the debugger should stop on this function call, invoke the user_call() method (which should be overridden in subclasses). Raise a BdbQuit exception if the quitting flag is set (which can be set from user_call()). Return a reference to the trace_dispatch() method for further tracing in that scope.

dispatch_return(frame, arg)

If the debugger should stop on this function return, invoke the user_return() method (which should be overridden in subclasses). Raise a BdbQuit exception if the quitting flag is set (which can be set from user_return()). Return a reference to the trace_dispatch() method for further tracing in that scope.

dispatch_exception(frame, arg)

If the debugger should stop at this exception, invokes the user_exception() method (which should be overridden in subclasses). Raise a BdbQuit exception if the quitting flag is set (which can be set from user_exception()). Return a reference to the trace_dispatch() method for further tracing in that scope.

일반적으로 파생된 클래스는 다음 메서드를 재정의하지 않지만, 중지와 중단점의 정의를 재정의하려고 하면 그럴 수 있습니다.

is_skipped_line(module_name)

Return True if module_name matches any skip pattern.

stop_here(frame)

Return True if frame is below the starting frame in the stack.

break_here(frame)

Return True if there is an effective breakpoint for this line.

Check whether a line or function breakpoint exists and is in effect. Delete temporary breakpoints based on information from effective().

break_anywhere(frame)

Return True if any breakpoint exists for frame’s filename.

파생 클래스는 디버거 연산을 제어하기 위해 이 메서드를 재정의해야 합니다.

user_call(frame, argument_list)

Called from dispatch_call() if a break might stop inside the called function.

argument_list is not used anymore and will always be None. The argument is kept for backwards compatibility.

user_line(frame)

Called from dispatch_line() when either stop_here() or break_here() returns True.

user_return(frame, return_value)

Called from dispatch_return() when stop_here() returns True.

user_exception(frame, exc_info)

Called from dispatch_exception() when stop_here() returns True.

do_clear(arg)

중단점이 일시적일 때 중단점을 제거하는 방법을 처리합니다.

이 메서드는 파생 클래스에서 구현해야 합니다.

파생 클래스와 클라이언트는 다음 메서드를 호출하여 스테핑(stepping) 상태에 영향을 줄 수 있습니다.

set_step()

한 줄의 코드 후에 멈춥니다.

set_next(frame)

주어진 프레임 내 또는 아래의 다음 줄에서 멈춥니다.

set_return(frame)

주어진 프레임에서 반환할 때 멈춥니다.

set_until(frame, lineno=None)

Stop when the line with the lineno greater than the current one is reached or when returning from current frame.

set_trace([frame])

frame에서 디버깅을 시작합니다. frame을 지정하지 않으면 호출자의 프레임에서 디버깅을 시작합니다.

버전 3.13에서 변경: set_trace() will enter the debugger immediately, rather than on the next line of code to be executed.

set_continue()

중단점에서나 완료 시에만 멈춥니다. 중단점이 없으면, 시스템 추적 함수를 None으로 설정합니다.

set_quit()

Set the quitting attribute to True. This raises BdbQuit in the next call to one of the dispatch_*() methods.

파생 클래스와 클라이언트는 다음 메서드를 호출하여 중단점을 조작할 수 있습니다. 이 메서드는 문제가 발생하면 에러 메시지가 포함된 문자열을 반환하고, 모두 정상이면 None을 반환합니다.

set_break(filename, lineno, temporary=False, cond=None, funcname=None)

새로운 중단점을 설정합니다. 인자로 전달된 filename에 lineno 줄이 없으면 에러 메시지를 반환합니다. canonic() 메서드에 설명된 대로 filename은 규범적 형식이어야 합니다.

clear_break(filename, lineno)

Delete the breakpoints in filename and lineno. If none were set, return an error message.

clear_bpbynumber(arg)

Breakpoint.bpbynumber에서 인덱스 arg인 중단점을 삭제합니다. arg가 숫자가 아니거나 범위를 벗어나면, 에러 메시지를 반환합니다.

clear_all_file_breaks(filename)

Delete all breakpoints in filename. If none were set, return an error message.

clear_all_breaks()

Delete all existing breakpoints. If none were set, return an error message.

get_bpbynumber(arg)

주어진 숫자로 지정된 중단점을 반환합니다. arg가 문자열이면, 숫자로 변환됩니다. arg가 숫자가 아닌 문자열이면, 지정된 중단점이 존재하지 않거나 삭제되었으면, ValueError가 발생합니다.

Added in version 3.2.

get_break(filename, lineno)

Return True if there is a breakpoint for lineno in filename.

get_breaks(filename, lineno)

filename의 lineno에 있는 모든 중단점을 반환하거나, 없으면 빈 리스트를 반환합니다.

get_file_breaks(filename)

filename의 모든 중단점을 반환하거나, 없으면 빈 리스트를 반환합니다.

get_all_breaks()

설정된 모든 중단점을 반환합니다.

파생 클래스와 클라이언트는 다음 메서드를 호출하여 스택 추적을 나타내는 데이터 구조를 얻을 수 있습니다.

get_stack(f, t)

Return a list of (frame, lineno) tuples in a stack trace, and a size.

The most recently called frame is last in the list. The size is the number of frames below the frame where the debugger was invoked.

format_stack_entry(frame_lineno, lprefix=': ')

Return a string with information about a stack entry, which is a (frame, lineno) tuple. The return string contains:

The canonical filename which contains the frame.

The function name or "<lambda>".

입력 인자.

반환 값.

코드 줄 (있으면).

클라이언트가 문자열로 지정된 statement를 디버깅하기 위해 디버거를 사용하려면 다음 두 가지 메서드를 호출할 수 있습니다.

run(cmd, globals=None, locals=None)

Debug a statement executed via the exec() function. globals defaults to __main__.__dict__, locals defaults to globals.

runeval(expr, globals=None, locals=None)

eval() 함수를 통해 실행된 표현식을 디버그합니다. globals와 locals는 run()과 같은 의미입니다.

runctx(cmd, globals, locals)

이전 버전과의 호환성을 위해. run() 메서드를 호출합니다.

runcall(func, /, *args, **kwds)

단일 함수 호출을 디버그하고, 결과를 반환합니다.

마지막으로, 모듈은 다음과 같은 함수를 정의합니다:

bdb.checkfuncname(b, frame)

Return True if we should break here, depending on the way the Breakpoint b was set.

If it was set via line number, it checks if b.line is the same as the one in frame. If the breakpoint was set via function name, we have to check we are in the right frame (the right function) and if we are on its first executable line.

bdb.effective(file, line, frame)

Return (active breakpoint, delete temporary flag) or (None, None) as the breakpoint to act upon.

The active breakpoint is the first entry in bplist for the (file, line) (which must exist) that is enabled, for which checkfuncname() is true, and that has neither a false condition nor positive ignore count. The flag, meaning that a temporary breakpoint should be deleted, is False only when the cond cannot be evaluated (in which case, ignore count is ignored).

If no such entry exists, then (None, None) is returned.

bdb.set_trace()

호출자의 프레임에서 Bdb 인스턴스로 디버깅을 시작합니다.

faulthandler — Dump the Python traceback

Added in version 3.3.

This module contains functions to dump Python tracebacks explicitly, on a fault, after a timeout, or on a user signal. Call faulthandler.enable() to install fault handlers for the SIGSEGV, SIGFPE, SIGABRT, SIGBUS, and SIGILL signals. You can also enable them at startup by setting the PYTHONFAULTHANDLER environment variable or by using the -X faulthandler command line option.

The fault handler is compatible with system fault handlers like Apport or the Windows fault handler. The module uses an alternative stack for signal handlers if the sigaltstack() function is available. This allows it to dump the traceback even on a stack overflow.

결함 처리기는 치명적일 때 호출되므로 시그널 안전한 함수만 사용할 수 있습니다 (예를 들어, 힙에 메모리를 할당할 수 없습니다). 이 제한 때문에 일반적인 파이썬 트레이스백에 비해 트레이스백 덤프는 최소화됩니다:

ASCII만 지원됩니다. 인코딩 시 backslashreplace 에러 처리기가 사용됩니다.

각 문자열은 500자로 제한됩니다.

파일명, 함수 이름 및 줄 번호만 표시됩니다. (소스 코드 없음)

100프레임과 100스레드로 제한됩니다.

순서가 뒤집힙니다: 가장 최근의 호출이 먼저 표시됩니다.

기본적으로, 파이썬 트레이스백은 sys.stderr에 기록됩니다. 트레이스백을 보려면, 응용 프로그램이 터미널에서 실행되어야 합니다. 로그 파일을 faulthandler.enable()로 전달할 수도 있습니다.

모듈은 C로 구현되어 있으므로, 충돌 시나 파이썬이 교착 상태에 빠질 때 트레이스백을 덤프할 수 있습니다.

파이썬 개발 모드는 파이썬 시작 시 faulthandler.enable()을 호출합니다.

더 보기

Module pdb

Interactive source code debugger for Python programs.

Module traceback

Standard interface to extract, format and print stack traces of Python programs.

트레이스백 덤프하기

faulthandler.dump_traceback(file=sys.stderr, all_threads=True)

모든 스레드의 트레이스백을 file로 덤프합니다. all_threads가 False면, 현재 스레드만 덤프합니다.

더 보기

traceback.print_tb(), which can be used to print a traceback object.

버전 3.5에서 변경: 이 함수에 파일 기술자를 전달하는 지원이 추가되었습니다.

결함 처리기 상태

faulthandler.enable(file=sys.stderr, all_threads=True)

Enable the fault handler: install handlers for the SIGSEGV, SIGFPE, SIGABRT, SIGBUS and SIGILL signals to dump the Python traceback. If all_threads is True, produce tracebacks for every running thread. Otherwise, dump only the current thread.

file은 결함 처리기가 비활성화될 때까지 열려 있어야 합니다: 파일 기술자 관련 문제를 참조하십시오.

버전 3.5에서 변경: 이 함수에 파일 기술자를 전달하는 지원이 추가되었습니다.

버전 3.6에서 변경: 윈도우에서는, 윈도우 예외(Windows exception) 처리기도 설치됩니다.

버전 3.10에서 변경: The dump now mentions if a garbage collector collection is running if all_threads is true.

faulthandler.disable()

결함 처리기를 비활성화합니다: enable()로 설치된 시그널 처리기를 제거합니다.

faulthandler.is_enabled()

결함 처리기가 활성화되었는지 검사합니다.

시간 초과 후에 트레이스백 덤프하기

faulthandler.dump_traceback_later(timeout, repeat=False, file=sys.stderr, exit=False)

Dump the tracebacks of all threads, after a timeout of timeout seconds, or every timeout seconds if repeat is True. If exit is True, call _exit() with status=1 after dumping the tracebacks. (Note _exit() exits the process immediately, which means it doesn’t do any cleanup like flushing file buffers.) If the function is called twice, the new call replaces previous parameters and resets the timeout. The timer has a sub-second resolution.

file은 트레이스백이 덤프 되거나 cancel_dump_traceback_later()가 호출될 때까지 열려 있어야 합니다: 파일 기술자 관련 문제를 참조하십시오.

이 함수는 워치독(watchdog) 스레드를 사용하여 구현됩니다.

버전 3.5에서 변경: 이 함수에 파일 기술자를 전달하는 지원이 추가되었습니다.

버전 3.7에서 변경: 이 함수는 이제 항상 사용할 수 있습니다.

faulthandler.cancel_dump_traceback_later()

마지막 dump_traceback_later() 호출을 취소합니다.

사용자 시그널에 트레이스백 덤프하기

faulthandler.register(signum, file=sys.stderr, all_threads=True, chain=False)

사용자 시그널을 등록합니다: signum 시그널에 대한 처리기를 설치해서, 모든 스레드, 또는 all_threads가 False면 현재 스레드의, 트레이스백을 file로 덤프합니다. chain이 True면 이전 처리기를 호출합니다.

file은 시그널이 unregister()로 등록 해지 될 때까지 열려 있어야 합니다: 파일 기술자 관련 문제를 참조하십시오.

윈도우에서는 사용할 수 없습니다.

버전 3.5에서 변경: 이 함수에 파일 기술자를 전달하는 지원이 추가되었습니다.

faulthandler.unregister(signum)

사용자 시그널을 등록 해지합니다: register()로 설치된 signum 시그널 처리기를 제거합니다. 시그널이 등록되었으면 True를 반환하고, 그렇지 않으면 False를 반환합니다.

윈도우에서는 사용할 수 없습니다.

파일 기술자 관련 문제

enable(), dump_traceback_later() 및 register()는 file 인자의 파일 기술자를 유지합니다. 파일이 닫히고 파일 기술자가 새 파일에 의해 다시 사용되거나, os.dup2()가 파일 기술자를 바꾸는 데 사용되면, 트레이스백이 다른 파일에 기록됩니다. 파일을 바꿀 때마다 이 함수들을 다시 호출하십시오.

예제

리눅스에서 결함 처리기를 활성화하거나 그렇지 않았을 때의 세그멘테이션 결함 예제:

$ python -c "import ctypes; ctypes.string_at(0)"
Segmentation fault

$ python -q -X faulthandler
>>> import ctypes
>>> ctypes.string_at(0)
Fatal Python error: Segmentation fault

Current thread 0x00007fb899f39700 (most recent call first):
  File "/home/python/cpython/Lib/ctypes/__init__.py", line 486 in string_at
  File "<stdin>", line 1 in <module>
Segmentation fault

pdb — 파이썬 디버거

소스 코드: Lib/pdb.py [https://github.com/python/cpython/tree/main/Lib/pdb.py]

pdb 모듈은 파이썬 프로그램을 위한 대화형 소스 코드 디버거를 정의합니다. 소스 라인 단계의 중단점(breakpoint) 및 단계 실행(single stepping) 설정, 스택 프레임 검사, 소스 코드 목록, 그리고 모든 스택 프레임의 컨텍스트에서 임의의 파이썬 코드 평가를 지원합니다. 또한 포스트-모템(post-mortem) 디버깅을 지원하며, 프로그램 제어 하에서도 호출될 수 있습니다.

이 디버거는 확장이 가능합니다 – 디버거는 실제로 Pdb 클래스로 정의됩니다. 현재 문서화되어 있진 않지만, 소스를 읽어보시면 쉽게 이해하실 수 있습니다. 확장 인터페이스는 bdb 와 cmd 모듈을 활용합니다.

더 보기

Module faulthandler

Used to dump Python tracebacks explicitly, on a fault, after a timeout, or on a user signal.

Module traceback

Standard interface to extract, format and print stack traces of Python programs.

The typical usage to break into the debugger is to insert:

import pdb; pdb.set_trace()

Or:

breakpoint()

at the location you want to break into the debugger, and then run the program. You can then step through the code following this statement, and continue running without the debugger using the continue command.

버전 3.7에서 변경: The built-in breakpoint(), when called with defaults, can be used instead of import pdb; pdb.set_trace().

def double(x):
   breakpoint()
   return x * 2
val = 3
print(f"{val} * 2 is {double(val)}")

The debugger’s prompt is (Pdb), which is the indicator that you are in debug mode:

> ...(2)double()
-> breakpoint()
(Pdb) p x
3
(Pdb) continue
3 * 2 is 6

버전 3.3에서 변경: readline 모듈을 통한 탭-완성은 명령과 명령 인자에 사용할 수 있습니다, 예를 들면, 현재 전역 및 지역 이름들은 p 명령의 인자로 제공됩니다.

You can also invoke pdb from the command line to debug other scripts. For example:

python -m pdb myscript.py

When invoked as a module, pdb will automatically enter post-mortem debugging if the program being debugged exits abnormally. After post-mortem debugging (or after normal exit of the program), pdb will restart the program. Automatic restarting preserves pdb’s state (such as breakpoints) and in most cases is more useful than quitting the debugger upon program’s exit.

버전 3.2에서 변경: Added the -c option to execute commands as if given in a .pdbrc file; see 디버거 명령들.

버전 3.7에서 변경: Added the -m option to execute modules similar to the way python -m does. As with a script, the debugger will pause execution just before the first line of the module.

Typical usage to execute a statement under control of the debugger is:

>>> import pdb
>>> def f(x):
...     print(1 / x)
>>> pdb.run("f(2)")
> <string>(1)<module>()
(Pdb) continue
0.5
>>>

에러가 발생하는 프로그램을 검사하는 일반적인 사용법은 다음과 같습니다:

>>> import pdb
>>> def f(x):
...     print(1 / x)
...
>>> f(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in f
ZeroDivisionError: division by zero
>>> pdb.pm()
> <stdin>(2)f()
(Pdb) p x
0
(Pdb)

버전 3.13에서 변경: The implementation of PEP 667 [https://peps.python.org/pep-0667/] means that name assignments made via pdb will immediately affect the active scope, even when running inside an optimized scope.

이 모듈은 다음과 같은 함수를 정의합니다; 각 함수는 조금 다른 방식으로 디버거로 진입합니다:

pdb.run(statement, globals=None, locals=None)

디버거 제어하에 statement (주어진 문자열 또는 코드 객체)를 실행합니다. 코드가 실행하기 전에 디버거 프롬프트가 나타납니다; 중단점을 지정하고 continue를 입력하거나, step 또는 next를 통해 문장을 단계별로 살펴볼 수 있습니다. (이 모든 명령은 아래에 설명되어 있습니다.) 선택적 인자 globals 와 locals는 코드가 실행되는 환경을 구체적으로 명시합니다; 기본적으로는 이 모듈의 딕셔너리 __main__ 이 사용됩니다. (내장 함수 exec() 또는 eval() 에 대한 설명 참조.)

pdb.runeval(expression, globals=None, locals=None)

Evaluate the expression (given as a string or a code object) under debugger control. When runeval() returns, it returns the value of the expression. Otherwise this function is similar to run().

pdb.runcall(function, *args, **kwds)

주어진 인자와 함께 function (문자열이 아닌, 함수 또는 메서드 객체)를 호출합니다. runcall() 이 반환될 때, 함수 호출로 반환된 값을 반환합니다. 디버거 프롬프트는 함수에 진입하자마자 나타납니다.

pdb.set_trace(*, header=None, commands=None)

Enter the debugger at the calling stack frame. This is useful to hard-code a breakpoint at a given point in a program, even if the code is not otherwise being debugged (e.g. when an assertion fails). If given, header is printed to the console just before debugging begins. The commands argument, if given, is a list of commands to execute when the debugger starts.

버전 3.7에서 변경: 키워드 전용 인자 header.

버전 3.13에서 변경: set_trace() will enter the debugger immediately, rather than on the next line of code to be executed.

Added in version 3.14: The commands argument.

pdb.post_mortem(traceback=None)

주어진 traceback 객체의 포스트-모템(post-mortem) 디버깅으로 진입합니다. 만약 traceback이 주어지지 않았다면, 현재 처리되고 있는 하나의 예외를 사용합니다. (기본값을 사용하는 경우 예외는 반드시 처리되고 있어야 합니다.)

pdb.pm()

Enter post-mortem debugging of the exception found in sys.last_exc.

run* 함수와 set_trace()는 Pdb 클래스를 인스턴스 화하고 같은 이름의 메서드를 호출하는 에일리어스(alias) 입니다. 더 많은 기능에 액세스하려면, 아래를 참고하여 직접 하셔야 합니다:

class pdb.Pdb(completekey='tab', stdin=None, stdout=None, skip=None, nosigint=False, readrc=True, mode=None)

Pdb 는 디버거 클래스입니다.

completekey, stdin 그리고 stdout 인자는 내부 cmd.Cmd 클래스로 전달됩니다; 자세한 설명은 해당 클래스에서 확인할 수 있습니다.

skip 인자가 주어진다면, 반드시 글로브-스타일(glob-style) 모듈 이름 패턴의 이터러블(iterable) 이어야 합니다. 디버거는 이 패턴 중 하나와 일치하는 모듈에서 시작되는 프레임 단계로 들어가지 않습니다. [1]

By default, Pdb sets a handler for the SIGINT signal (which is sent when the user presses Ctrl-C on the console) when you give a continue command. This allows you to break into the debugger again by pressing Ctrl-C. If you want Pdb not to touch the SIGINT handler, set nosigint to true.

readrc 인자는 기본적으로 참이고 Pdb가 파일 시스템으로부터 .pdbrc를 불러올지 여부를 제어합니다.

The mode argument specifies how the debugger was invoked. It impacts the workings of some debugger commands. Valid values are 'inline' (used by the breakpoint() builtin), 'cli' (used by the command line invocation) or None (for backwards compatible behaviour, as before the mode argument was added).

skip으로 추적하기 위한 호출 예시:

import pdb; pdb.Pdb(skip=['django.*']).set_trace()

인자 없이 감사 이벤트 pdb.Pdb를 발생시킵니다.

버전 3.1에서 변경: Added the skip parameter.

버전 3.2에서 변경: Added the nosigint parameter. Previously, a SIGINT handler was never set by Pdb.

버전 3.6에서 변경: readrc 인자.

Added in version 3.14: Added the mode argument.

run(statement, globals=None, locals=None)

runeval(expression, globals=None, locals=None)

runcall(function, *args, **kwds)

set_trace()

위에 설명된 함수에 대한 설명서를 참조하시면 됩니다.

디버거 명령들

디버거가 인식할 수 있는 명령이 아래 나열되어 있습니다. 대부분의 명령은 한두 문자로 단축될 수 있습니다; 예를 들면, h(elp) 는 h 또는 help로 help 명령을 입력할 때 사용할 수 있습니다. (하지만 he, hel, H, Help 또는 HELP는 사용할 수 없습니다.) 인자는 반드시 명령과 공백(스페이스나 탭)으로 분리되어야 합니다. 선택적 인자는 명령 문법에서 대괄호([])로 묶여있습니다; 대괄호는 입력하지 않습니다. 명령 문법에서 대체 가능한 인자는 세로 바(|)로 분리되어 있습니다.

빈 줄을 입력하면 마지막으로 입력된 명령이 반복됩니다. 예외: 만약 마지막 명령이 list 명령이면, 다음 11줄이 나열됩니다.

디버거가 인식하지 못하는 명령은 파이썬 문장으로 가정하고 디버깅 중인 프로그램의 컨텍스트에서 실행됩니다. 파이썬 문장 앞에 느낌표(!)를 붙여 사용할 수도 있습니다. 이 방법은 디버깅 중인 프로그램을 검사하는 강력한 방법입니다. 변수를 변경하거나 함수를 호출하는 것도 가능합니다. 이 문장에서 예외가 발생하면, 예외 명은 출력되지만 디버거의 상태는 변경되지 않습니다.

버전 3.13에서 변경: Expressions/Statements whose prefix is a pdb command are now correctly identified and executed.

디버거는 에일리어스을 지원합니다. 에일리어스는 검사 중인 컨텍스트에서 특정 수준의 적응성을 허용하는 매개변수를 가질 수 있습니다.

Multiple commands may be entered on a single line, separated by ;;. (A single ; is not used as it is the separator for multiple commands in a line that is passed to the Python parser.) No intelligence is applied to separating the commands; the input is split at the first ;; pair, even if it is in the middle of a quoted string. A workaround for strings with double semicolons is to use implicit string concatenation ';'';' or ";"";".

To set a temporary global variable, use a convenience variable. A convenience variable is a variable whose name starts with $. For example, $foo = 1 sets a global variable $foo which you can use in the debugger session. The convenience variables are cleared when the program resumes execution so it’s less likely to interfere with your program compared to using normal variables like foo = 1.

There are three preset convenience variables:

$_frame: the current frame you are debugging

$_retval: the return value if the frame is returning

$_exception: the exception if the frame is raising an exception

Added in version 3.12: Added the convenience variable feature.

If a file .pdbrc exists in the user’s home directory or in the current directory, it is read with 'utf-8' encoding and executed as if it had been typed at the debugger prompt, with the exception that empty lines and lines starting with # are ignored. This is particularly useful for aliases. If both files exist, the one in the home directory is read first and aliases defined there can be overridden by the local file.

버전 3.2에서 변경: .pdbrc 는 continue와 next같이 디버깅을 계속하는 명령을 포함할 수 있습니다. 이전에는, 이런 명령이 효과가 없었습니다.

버전 3.11에서 변경: .pdbrc is now read with 'utf-8' encoding. Previously, it was read with the system locale encoding.

h(elp) [command]

인자가 없는 경우에는, 사용 가능한 명령 리스트를 출력합니다. command 인자가 주어진 경우에는, 해당 명령의 도움말을 출력합니다. help pdb 는 전체 문서(pdb 모듈의 독스트링)를 표시합니다. command 인자는 반드시 식별자이어야 하므로, ! 명령의 도움말을 얻기 위해서 help exec 가 꼭 입력되어야 합니다.

w(here) [count]

Print a stack trace, with the most recent frame at the bottom. if count is 0, print the current frame entry. If count is negative, print the least recent - count frames. If count is positive, print the most recent count frames. An arrow (>) indicates the current frame, which determines the context of most commands.

버전 3.14에서 변경: count argument is added.

d(own) [count]

스택 트레이스에서 현재 프레임을 count (기본 1) 단계 아래로 (새로운 프레임으로) 이동합니다.

u(p) [count]

스택 트레이스에서 현재 프레임을 count (기본 1) 단계 위로 (이전 프레임으로) 이동합니다.

b(reak) [([filename:]lineno | function) [, condition]]

With a lineno argument, set a break at line lineno in the current file. The line number may be prefixed with a filename and a colon, to specify a breakpoint in another file (possibly one that hasn’t been loaded yet). The file is searched on sys.path. Acceptable forms of filename are /abspath/to/file.py, relpath/file.py, module and package.module.

With a function argument, set a break at the first executable statement within that function. function can be any expression that evaluates to a function in the current namespace.

두 번째 인자가 있는 경우, 중단점을 적용하기 전에 표현식이 반드시 참이어야 합니다.

인자가 없다면, 각 중단점, 중단점에 도달한 횟수, 현재까지 무시 횟수, 그리고 관련 조건(있는 경우)을 포함한 모든 중단지점을 나열합니다.

Each breakpoint is assigned a number to which all the other breakpoint commands refer.

tbreak [([filename:]lineno | function) [, condition]]

한번 도달하면 제거되는 임시중단점입니다. 인자는 break과 동일합니다.

cl(ear) [filename:lineno | bpnumber ...]

filename:lineno 인자가 주어진 경우, 해당 줄에 있는 모든 중단점을 제거합니다. 공백으로 구분된 중단점 번호 배열이 주어진 경우, 해당 중단점을 제거합니다. 인자가 없는 경우, 모든 중단지점을 재차 확인 후 제거합니다.

disable bpnumber [bpnumber ...]

공백으로 구분된 중단점 번호로 해당 중단점을 비활성화합니다. 중단점을 비활성화하는 것은 프로그램이 실행을 중단할 수 없다는 것입니다, 하지만 중단점을 제거하는 것과는 달리, 중단점 목록에 남아있으며 (재-)활성화할 수 있습니다.

enable bpnumber [bpnumber ...]

지정된 중단점을 활성화합니다.

ignore bpnumber [count]

Set the ignore count for the given breakpoint number. If count is omitted, the ignore count is set to 0. A breakpoint becomes active when the ignore count is zero. When non-zero, the count is decremented each time the breakpoint is reached and the breakpoint is not disabled and any associated condition evaluates to true.

condition bpnumber [condition]

중단점에 새로운 condition을 설정합니다, 표현식이 참일 때만 중단점이 적용됩니다. 만약 condition이 없다면, 설정되어있던 모든 조건이 제거됩니다; 즉, 중단점에 적용되어있던 조건이 없어집니다.

commands [bpnumber]

중단점 번호 bpnumber 에 대한 명령을 지정합니다. 명령 목록은 다음 줄에 나타나게 됩니다. 명령을 종료하려면 end만 입력하면 됩니다. 예를 들면:

(Pdb) commands 1
(com) p some_variable
(com) end
(Pdb)

중단점에 지정된 모든 명령을 제거하려면, commands 입력 후에 바로 end를 입력하면 됩니다; 즉, 아무 명령을 설정하지 않는 것입니다.

bpnumber 인자가 주어지지 않으면, commands는 마지막 중단점 묶음을 참조하게 됩니다.

중단점 명령을 활용해서 프로그램을 다시 시작할 수도 있습니다. continue 명령이나, step 또는 실행을 재개하는 다른 명령을 사용하기만 하면 됩니다.

Specifying any command resuming execution (currently continue, step, next, return, until, jump, quit and their abbreviations) terminates the command list (as if that command was immediately followed by end). This is because any time you resume execution (even with a simple next or step), you may encounter another breakpoint—which could have its own command list, leading to ambiguities about which list to execute.

If the list of commands contains the silent command, or a command that resumes execution, then the breakpoint message containing information about the frame is not displayed.

버전 3.14에서 변경: Frame information will not be displayed if a command that resumes execution is present in the command list.

s(tep)

현재 줄을 실행하고, 멈출 수 있는 가장 첫 번째 줄(호출되는 함수 또는 현재 함수의 다음 줄) 에서 멈춥니다.

n(ext)

현재 함수의 다음 줄에 도달하거나, 반환할 때까지 계속 실행합니다. next와 step의 차이점은 step은 호출된 함수 안에서 멈추고, next는 호출된 함수를 재빠르게 실행하고 현재 함수의 바로 다음 줄에서만 멈춥니다.

unt(il) [lineno]

인자가 없는 경우에는, 현재 줄 번호보다 높은 줄 번호에 도달할 때까지 계속 실행합니다.

With lineno, continue execution until a line with a number greater or equal to lineno is reached. In both cases, also stop when the current frame returns.

버전 3.2에서 변경: 줄 번호를 명시적으로 줄 수 있도록 허용합니다.

r(eturn)

현재 함수가 반환될 때까지 계속 실행합니다.

c(ont(inue))

중단점을 마주칠 때까지 계속 실행합니다.

j(ump) lineno

다음으로 실행될 줄을 설정할 수 있습니다. 프레임의 맨 마지막에서만 실행이 가능합니다. 이전 줄로 돌아가 코드를 재실행하거나, 실행을 원치 않는 코드를 건너뛸 수 있습니다.

중요한 점은 이 명령은 언제나 실행할 수 있진 않습니다 – for 루프 내부로 들어가거나 finally 절을 건너뛰는 것은 불가능합니다.

l(ist) [first[, last]]

현재 파일의 소스 코드를 나열합니다. 인자가 없는 경우, 현재 줄 주위로 11줄을 나열하거나 이전 줄을 이어서 나열합니다. 인자로 .을 입력한 경우, 현재 줄 주위로 11줄을 나열합니다. 한 인자만 주어진 경우, 해당 줄 주위로 11줄을 나열합니다. 두 인자가 주어진 경우, 두 인자 사이의 모든 줄을 나열합니다; 만약 두 번째 인자가 첫 번째 인자보다 작은 경우, 첫 번째 인자로부터 나열하는 줄 수로 인식합니다.

현재 프레임에서 현재 위치는 ->로 표시됩니다. 예외를 디버깅할 때, 예외가 최초로 발생하거나 전파된 줄이 현재 줄과 다른 경우에는 >>로 표시됩니다.

버전 3.2에서 변경: Added the >> marker.

ll | longlist

현재 함수나 프레임의 소스 코드 전체를 나열합니다. 참고할만한 줄은 list처럼 표시됩니다.

Added in version 3.2.

a(rgs)

Print the arguments of the current function and their current values.

p expression

Evaluate expression in the current context and print its value.

참고

디버거 명령은 아니지만, print()도 사용될 수 있습니다 — 이때는 파이썬의 print() 함수를 실행하게 됩니다.

pp expression

Like the p command, except the value of expression is pretty-printed using the pprint module.

whatis expression

Print the type of expression.

source expression

Try to get source code of expression and display it.

Added in version 3.2.

display [expression]

Display the value of expression if it changed, each time execution stops in the current frame.

Without expression, list all display expressions for the current frame.

참고

Display evaluates expression and compares to the result of the previous evaluation of expression, so when the result is mutable, display may not be able to pick up the changes.

Example:

lst = []
breakpoint()
pass
lst.append(1)
print(lst)

Display won’t realize lst has been changed because the result of evaluation is modified in place by lst.append(1) before being compared:

> example.py(3)<module>()
-> pass
(Pdb) display lst
display lst: []
(Pdb) n
> example.py(4)<module>()
-> lst.append(1)
(Pdb) n
> example.py(5)<module>()
-> print(lst)
(Pdb)

You can do some tricks with copy mechanism to make it work:

> example.py(3)<module>()
-> pass
(Pdb) display lst[:]
display lst[:]: []
(Pdb) n
> example.py(4)<module>()
-> lst.append(1)
(Pdb) n
> example.py(5)<module>()
-> print(lst)
display lst[:]: [1]  [old: []]
(Pdb)

Added in version 3.2.

undisplay [expression]

Do not display expression anymore in the current frame. Without expression, clear all display expressions for the current frame.

Added in version 3.2.

interact

Start an interactive interpreter (using the code module) in a new global namespace initialised from the local and global namespaces for the current scope. Use exit() or quit() to exit the interpreter and return to the debugger.

참고

As interact creates a new dedicated namespace for code execution, assignments to variables will not affect the original namespaces. However, modifications to any referenced mutable objects will be reflected in the original namespaces as usual.

Added in version 3.2.

버전 3.13에서 변경: exit() and quit() can be used to exit the interact command.

버전 3.13에서 변경: interact directs its output to the debugger’s output channel rather than sys.stderr.

alias [name [command]]

Create an alias called name that executes command. The command must not be enclosed in quotes. Replaceable parameters can be indicated by %1, %2, … and %9, while %* is replaced by all the parameters. If command is omitted, the current alias for name is shown. If no arguments are given, all aliases are listed.

에일리어스는 중첩될 수 있고 pdb 프롬프트 내에서 정당하게 입력할 수 있는 모든 것을 담을 수 있습니다. 주의할 점은 pdb 내부 명령들이 에일리어스에 의해 오버라이드 될 수 있습니다. 그 명령은 에일리어스가 없어질 때까지 사용할 수 없게 됩니다. 에일리어싱은 명령 줄의 첫 번째 단어에 회귀적으로 적용됩니다; 나머지 단어들은 적용되지 않습니다.

.pdbrc파일에 추가되면 특히 유용한 두 에일리어스 예시:

# Print instance variables (usage "pi classInst")
alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = {%1.__dict__[k]}")
# Print instance variables in self
alias ps pi self

unalias name

Delete the specified alias name.

! statement

Execute the (one-line) statement in the context of the current stack frame. The exclamation point can be omitted unless the first word of the statement resembles a debugger command, e.g.:

(Pdb) ! n=42
(Pdb)

To set a global variable, you can prefix the assignment command with a global statement on the same line, e.g.:

(Pdb) global list_options; list_options = ['-l']
(Pdb)

run [args ...]

restart [args ...]

Restart the debugged Python program. If args is supplied, it is split with shlex and the result is used as the new sys.argv. History, breakpoints, actions and debugger options are preserved. restart is an alias for run.

버전 3.14에서 변경: run and restart commands are disabled when the debugger is invoked in 'inline' mode.

q(uit)

디버거를 종료합니다. 실행되고 있는 프로그램이 종료됩니다.

debug code

Enter a recursive debugger that steps through code (which is an arbitrary expression or statement to be executed in the current environment).

retval

Print the return value for the last return of the current function.

exceptions [excnumber]

List or jump between chained exceptions.

When using pdb.pm() or Pdb.post_mortem(...) with a chained exception instead of a traceback, it allows the user to move between the chained exceptions using exceptions command to list exceptions, and exception <number> to switch to that exception.

Example:

def out():
    try:
        middle()
    except Exception as e:
        raise ValueError("reraise middle() error") from e

def middle():
    try:
        return inner(0)
    except Exception as e:
        raise ValueError("Middle fail")

def inner(x):
    1 / x

 out()

calling pdb.pm() will allow to move between exceptions:

> example.py(5)out()
-> raise ValueError("reraise middle() error") from e

(Pdb) exceptions
  0 ZeroDivisionError('division by zero')
  1 ValueError('Middle fail')
> 2 ValueError('reraise middle() error')

(Pdb) exceptions 0
> example.py(16)inner()
-> 1 / x

(Pdb) up
> example.py(10)middle()
-> return inner(0)

Added in version 3.13.

각주

[1]

프레임이 특정 모듈에서 시작되는 것으로 간주하는지 여부는 프레임 전역에 있는 __name__에 의해 결정됩니다.

파이썬 프로파일러

소스 코드: Lib/profile.py [https://github.com/python/cpython/tree/main/Lib/profile.py] 및 Lib/pstats.py [https://github.com/python/cpython/tree/main/Lib/pstats.py]

프로파일러 소개

cProfile과 profile은 파이썬 프로그램의 결정론적 프로파일링 (deterministic profiling)을 제공합니다. 프로파일 (profile)은 프로그램의 여러 부분이 얼마나 자주 그리고 얼마나 오랫동안 실행되었는지를 기술하는 통계 집합입니다. 이러한 통계는 pstats 모듈을 통해 보고서로 포매팅 할 수 있습니다.

파이썬 표준 라이브러리는 같은 프로파일링 인터페이스의 두 가지 구현을 제공합니다:

cProfile이 대부분 사용자에게 권장됩니다; 오래 실행되는 프로그램을 프로파일링하는 데 적합한 합리적인 부하를 주는 C 확장입니다. Brett Rosen과 Ted Czotter가 제공한 lsprof를 기반으로 합니다.

profile은 순수 파이썬 모듈이고 이 인터페이스를 cProfile이 모방했습니다. 하지만, 프로파일링 되는 프로그램에 상당한 부하를 추가합니다. 어떤 방식으로 프로파일러를 확장하려고 한다면, 이 모듈을 사용하면 작업이 더 쉬울 수 있습니다. Jim Roskind가 원래 설계하고 작성했습니다.

참고

프로파일러 모듈은 벤치마킹 목적(이를 위해서는 합리적으로 정확한 결과를 주는 timeit이 있습니다)이 아니라 주어진 프로그램에 대한 실행 프로파일을 제공하도록 설계되었습니다. 이것은 특히 C 코드에 대한 파이썬 코드 벤치마킹에 적용됩니다: 프로파일러는 파이썬 코드에 부하를 가하지만, C 수준 함수에는 그렇지 않아서 C 코드는 모든 파이썬 코드보다 빨라 보입니다.

즉석 사용자 설명서

이 섹션은 “설명서를 읽고 싶지 않은” 사용자를 위해 제공됩니다. 매우 간단한 개요를 제공하며, 사용자가 기존 응용 프로그램에서 프로파일링을 빠르게 수행할 수 있도록 합니다.

단일 인자를 취하는 함수를 프로파일링하려면, 이렇게 할 수 있습니다:

import cProfile
import re
cProfile.run('re.compile("foo|bar")')

(시스템에서 cProfile을 사용할 수 없으면 대신 profile을 사용하십시오.)

위의 작업은 re.compile()을 실행하고 다음과 같은 프로파일 결과를 인쇄합니다:

      214 function calls (207 primitive calls) in 0.002 seconds

Ordered by: cumulative time

ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     1    0.000    0.000    0.002    0.002 {built-in method builtins.exec}
     1    0.000    0.000    0.001    0.001 <string>:1(<module>)
     1    0.000    0.000    0.001    0.001 __init__.py:250(compile)
     1    0.000    0.000    0.001    0.001 __init__.py:289(_compile)
     1    0.000    0.000    0.000    0.000 _compiler.py:759(compile)
     1    0.000    0.000    0.000    0.000 _parser.py:937(parse)
     1    0.000    0.000    0.000    0.000 _compiler.py:598(_code)
     1    0.000    0.000    0.000    0.000 _parser.py:435(_parse_sub)

The first line indicates that 214 calls were monitored. Of those calls, 207 were primitive, meaning that the call was not induced via recursion. The next line: Ordered by: cumulative time indicates the output is sorted by the cumtime values. The column headings include:

ncalls

호출 수.

tottime

주어진 함수에서 소비된 총 시간 (서브 함수 호출에 든 시간은 제외합니다)

percall

tottime을 ncalls로 나눈 몫

cumtime

이 함수와 모든 서브 함수에서 소요된 누적 시간 (호출에서 종료까지). 이 수치는 재귀 함수에서도 정확합니다.

percall

cumtime을 프리미티브 호출로 나눈 몫

filename:lineno(function)

각 함수의 해당 데이터를 제공합니다 – 파일명:줄 번호(함수)

첫 번째 열에 두 개의 숫자가 있으면 (예를 들어 3/1), 함수가 재귀 되었음을 의미합니다. 두 번째 값은 프리미티브 호출 수이고 앞엣것은 총 호출 수입니다. 함수가 재귀 되지 않으면, 이 두 값은 같으며, 한 숫자만 인쇄됩니다.

프로파일 실행의 끝에 출력을 인쇄하는 대신, run() 함수에 파일명을 지정하여 결과를 파일에 저장할 수 있습니다:

import cProfile
import re
cProfile.run('re.compile("foo|bar")', 'restats')

pstats.Stats 클래스는 파일에서 프로파일 결과를 읽고 다양한 방식으로 포맷합니다.

cProfile과 profile을 스크립트로 호출하여 다른 스크립트를 프로파일링 할 수도 있습니다. 예를 들면:

python -m cProfile [-o output_file] [-s sort_order] (-m module | myscript.py)

-o는 stdout 대신 파일에 프로파일 결과를 씁니다.

-s는 출력을 정렬할 sort_stats() 정렬 값 중 하나를 지정합니다. 이는 -o가 제공되지 않은 경우에만 적용됩니다.

-m은 스크립트 대신 모듈이 프로파일링 되도록 지정합니다.

Added in version 3.7: -m 옵션을 cProfile에 추가했습니다.

Added in version 3.8: -m 옵션을 profile에 추가했습니다.

pstats 모듈의 Stats 클래스에는 프로파일 결과 파일에 저장된 데이터를 조작하고 인쇄하기 위한 다양한 메서드가 있습니다:

import pstats
from pstats import SortKey
p = pstats.Stats('restats')
p.strip_dirs().sort_stats(-1).print_stats()

strip_dirs() 메서드는 모든 모듈 이름에서 외부 경로를 제거했습니다. sort_stats() 메서드는 인쇄되는 표준 모듈/줄/이름 문자열에 따라 모든 항목을 정렬했습니다. print_stats() 메서드는 모든 통계를 인쇄했습니다. 다음과 같은 정렬 호출을 시도할 수 있습니다:

p.sort_stats(SortKey.NAME)
p.print_stats()

첫 번째 호출은 실제로 함수 이름으로 목록을 정렬하고, 두 번째 호출은 통계를 인쇄합니다. 다음은 몇 가지 흥미로운 실험 호출입니다:

p.sort_stats(SortKey.CUMULATIVE).print_stats(10)

이것은 함수에서의 누적 시간을 기준으로 프로파일을 정렬한 다음, 가장 중요한 10개의 줄만 인쇄합니다. 시간이 걸리는 알고리즘을 이해하려면, 위의 줄을 사용하십시오.

어떤 함수가 많이 반복되고 많은 시간이 걸리는지 알고 싶다면, 다음을 수행하여:

p.sort_stats(SortKey.TIME).print_stats(10)

각 함수 내에서 소비한 시간에 따라 정렬한 다음, 상위 10개 함수에 대한 통계를 인쇄하십시오.

다음과 같은 것도 시도해 볼 수 있습니다:

p.sort_stats(SortKey.FILENAME).print_stats('__init__')

이렇게 하면 모든 통계가 파일 이름으로 정렬된 다음, 클래스 초기화(init) 메서드에 대한 통계만 인쇄됩니다 (이들의 철자가 __init__이기 때문입니다). 마지막 예로, 다음을 시도해 볼 수 있습니다:

p.sort_stats(SortKey.TIME, SortKey.CUMULATIVE).print_stats(.5, 'init')

이 줄은 주 시간 키와 누적 시간 보조 키로 통계를 정렬한 다음, 일부 통계를 인쇄합니다. 구체적으로, 목록을 먼저 원래 크기의 50%(.5)로 줄인 다음, init를 포함하는 줄만 유지되고, 그 서브 서브 목록이 인쇄됩니다.

어떤 함수가 위의 함수를 호출했는지 궁금하다면, 이제 다음과 같이 할 수 있습니다 (p는 여전히 마지막 기준에 따라 정렬됩니다):

p.print_callers(.5, 'init')

그러면 나열된 각 함수에 대한 호출자 목록을 얻습니다.

더 많은 기능을 원하면, 매뉴얼을 읽거나, 다음 함수가 무엇인지 추측하십시오:

p.print_callees()
p.add('restats')

스크립트로 호출될 때, pstats 모듈은 프로파일 덤프를 읽고 검사하기 위한 통계 브라우저입니다. 간단한 줄 지향 인터페이스(cmd를 사용하여 구현되었습니다)와 대화식 도움말이 있습니다.

profile과 cProfile 모듈 레퍼런스

profile과 cProfile 모듈은 모두 다음 함수를 제공합니다:

profile.run(command, filename=None, sort=-1)

이 함수는 exec() 함수에 전달할 수 있는 단일 인자와 선택적 파일 이름을 취합니다. 모든 경우에 이 루틴은 다음을 실행합니다:

exec(command, __main__.__dict__, __main__.__dict__)

그리고 실행으로부터 프로파일링 통계를 수집합니다. 파일 이름이 없으면, 이 함수는 자동으로 Stats 인스턴스를 만들고 간단한 프로파일링 보고서를 인쇄합니다. 정렬 값이 지정되면, 이 Stats 인스턴스로 전달되어 결과 정렬 방법을 제어합니다.

profile.runctx(command, globals, locals, filename=None, sort=-1)

This function is similar to run(), with added arguments to supply the globals and locals mappings for the command string. This routine executes:

exec(command, globals, locals)

그리고 위의 run() 함수에서와같이 프로파일링 통계를 수집합니다.

class profile.Profile(timer=None, timeunit=0.0, subcalls=True, builtins=True)

이 클래스는 일반적으로 cProfile.run() 함수가 제공하는 것보다 프로파일링에 대한 더 세밀한 제어가 필요할 때만 사용됩니다.

timer 인자를 통해 코드를 실행하는 데 걸리는 시간을 측정하기 위한 사용자 정의 타이머를 제공할 수 있습니다. 현재 시각을 나타내는 단일 숫자를 반환하는 함수여야 합니다. 숫자가 정수이면, timeunit는 각 시간 단위의 지속 시간을 지정하는 승수를 지정합니다. 예를 들어, 타이머가 밀리초 단위로 측정된 시간을 반환하면 시간 단위는 .001입니다.

Profile 클래스를 직접 사용하면 프로파일 데이터를 파일에 쓰지 않고도 프로파일 결과를 포맷할 수 있습니다:

import cProfile, pstats, io
from pstats import SortKey
pr = cProfile.Profile()
pr.enable()
# ... do something ...
pr.disable()
s = io.StringIO()
sortby = SortKey.CUMULATIVE
ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
ps.print_stats()
print(s.getvalue())

Profile 클래스는 컨텍스트 관리자로도 사용될 수 있습니다 (cProfile 모듈에서만 지원됩니다. 컨텍스트 관리자 형을 참조하십시오):

import cProfile

with cProfile.Profile() as pr:
    # ... do something ...

    pr.print_stats()

버전 3.8에서 변경: 컨텍스트 관리자 지원이 추가되었습니다.

enable()

프로파일링 데이터 수집을 시작합니다. cProfile에만 있습니다.

disable()

프로파일링 데이터 수집을 중지합니다. cProfile에만 있습니다.

create_stats()

프로파일링 데이터 수집을 중지하고 결과를 내부적으로 현재 프로파일로 기록합니다.

print_stats(sort=-1)

현재 프로파일을 기반으로 Stats 객체를 만들고 결과를 stdout에 인쇄합니다.

The sort parameter specifies the sorting order of the displayed statistics. It accepts a single key or a tuple of keys to enable multi-level sorting, as in Stats.sort_stats.

Added in version 3.13: print_stats() now accepts a tuple of keys.

dump_stats(filename)

현재 프로파일의 결과를 filename에 씁니다.

run(cmd)

exec()를 통해 cmd를 프로파일 합니다.

runctx(cmd, globals, locals)

지정된 전역과 지역 환경으로 exec()를 통해 cmd를 프로파일 합니다.

runcall(func, /, *args, **kwargs)

func(*args, **kwargs)를 프로파일 합니다

프로파일링은 호출된 명령/함수가 실제로 반환하는 경우에만 작동함에 유의하십시오. 인터프리터가 종료되면 (예를 들어 호출된 명령/함수 실행 중 sys.exit() 호출을 통해) 아무런 프로파일링 결과도 인쇄되지 않습니다.

Stats 클래스

프로파일러 데이터의 분석은 Stats 클래스를 사용하여 수행됩니다.

class pstats.Stats(*filenames or profile, stream=sys.stdout)

이 클래스 생성자는 filename(또는 파일명의 리스트)이나 Profile 인스턴스에서 “통계 객체”의 인스턴스를 만듭니다. 출력은 stream에 의해 지정된 스트림으로 인쇄됩니다.

위의 생성자에 의해 선택된 파일은 해당 버전의 profile이나 cProfile에 의해 만들어졌어야 합니다. 구체적으로, 이 프로파일러의 향후 버전에서 보장되는 파일 호환성은 없으며, 다른 프로파일러에서 생성된 파일이나 다른 운영 체제에서 실행되는 같은 프로파일러의 실행과 호환되지 않습니다. 여러 파일이 제공되면, 동일한 함수에 대한 모든 통계가 통합되므로, 여러 프로세스에 대한 전체 뷰를 단일 보고서에서 고려할 수 있습니다. 추가 파일을 기존 Stats 객체의 데이터와 결합해야 하면, add() 메서드를 사용할 수 있습니다.

파일에서 프로파일 데이터를 읽는 대신, cProfile.Profile이나 profile.Profile 객체를 프로파일 데이터 소스로 사용할 수 있습니다.

Stats 객체에는 다음과 같은 메서드가 있습니다:

strip_dirs()

Stats 클래스에 대한 이 메서드는 파일 이름에서 모든 선행 경로 정보를 제거합니다. 80열 이내에 (가깝게) 맞게 출력물의 크기를 줄이는 데 매우 유용합니다. 이 메서드는 객체를 수정하고, 제거된 정보는 손실됩니다. 제거 조작을 수행한 후, 객체는 객체 초기화와 로드 직후와 마찬가지로 “임의의” 순서로 항목을 가진 것으로 간주합니다. strip_dirs()로 인해 두 함수 이름이 구별할 수 없게 되면 (같은 파일 이름의 같은 줄에 있고, 함수 이름도 같습니다), 이 두 항목에 대한 통계는 단일 항목으로 누적됩니다.

add(*filenames)

Stats 클래스의 이 메서드는 추가 프로파일링 정보를 현재 프로파일링 객체에 누적합니다. 인자는 해당 버전의 profile.run()이나 cProfile.run()으로 만들어진 파일명을 참조해야 합니다. 동일한 이름을 가진 (파일, 줄, 이름) 함수에 대한 통계는 자동으로 단일 함수 통계에 축적됩니다.

dump_stats(filename)

Stats 객체에 로드된 데이터를 filename이라는 파일에 저장합니다. 파일이 없으면 만들어지고, 이미 존재하면 덮어씁니다. 이것은 profile.Profile과 cProfile.Profile 클래스에 있는 같은 이름의 메서드와 동등합니다.

sort_stats(*keys)

이 메서드는 제공된 기준에 따라 Stats 객체를 정렬하여 수정합니다. 인자는 정렬 기준을 식별하는 문자열이나 SortKey 열거형일 수 있습니다 (예: 'time', 'name', SortKey.TIME 또는 SortKey.NAME). SortKey 열거형 인자는 문자열 인자보다 안정적이고 에러가 적다는 점에서 문자열 인자보다 유리합니다.

둘 이상의 키가 제공되면, 그 앞에 선택된 모든 키가 같을 때 추가 키가 보조 기준으로 사용됩니다. 예를 들어, sort_stats(SortKey.NAME, SortKey.FILE)은 함수 이름에 따라 모든 항목을 정렬하고, 함수 이름이 같으면 파일 이름으로 정렬합니다.

문자열 인자의 경우, 약어가 모호하지 않은 한, 모든 키 이름에 약어를 사용할 수 있습니다.

유효한 문자열과 SortKey는 다음과 같습니다:

유효한 문자열 인자

유효한 열거형 인자

의미

'calls'

SortKey.CALLS

호출 수

'cumulative'

SortKey.CUMULATIVE

누적 시간

'cumtime'

해당 없음

누적 시간

'file'

해당 없음

파일 이름

'filename'

SortKey.FILENAME

파일 이름

'module'

해당 없음

파일 이름

'ncalls'

해당 없음

호출 수

'pcalls'

SortKey.PCALLS

프리미티브 호출 수

'line'

SortKey.LINE

줄 번호

'name'

SortKey.NAME

함수 이름

'nfl'

SortKey.NFL

이름/파일/줄

'stdname'

SortKey.STDNAME

표준 이름

'time'

SortKey.TIME

내부 시간

'tottime'

해당 없음

내부 시간

통계의 모든 정렬은 내림차순이고 (가장 시간이 오래 걸리는 항목을 앞에 놓습니다), 이름, 파일 및 줄 번호 검색은 오름차순(알파벳 순서)임에 유의하십시오. SortKey.NFL과 SortKey.STDNAME 간의 미묘한 차이점은 표준 이름이 인쇄된 이름의 일종이라는 것입니다. 즉, 포함된 줄 번호가 이상한 방식으로 비교됩니다. 예를 들어, 줄 3, 20 및 40은 (파일 이름이 같으면) 문자열 순서 20, 3 및 40으로 나타납니다. 반면에 SortKey.NFL은 줄 번호를 숫자로 비교합니다. 실제로, sort_stats(SortKey.NFL)은 sort_stats(SortKey.NAME, SortKey.FILENAME, SortKey.LINE)과 같습니다.

이전 버전과의 호환성을 위해, 숫자 인자 -1, 0, 1 및 2가 허용됩니다. 이들은 각각 'stdname', 'calls', 'time' 및 'cumulative'로 해석됩니다. 이 이전 스타일 형식(숫자)을 사용하면, 오직 하나의 정렬 키(숫자키)만 사용되며, 추가 인자는 조용히 무시됩니다.

Added in version 3.7: SortKey 열거형을 추가했습니다.

reverse_order()

Stats 클래스에 대한 이 메서드는 객체 내 기본 리스트의 순서를 뒤집습니다. 기본적으로 오름차순 대 내림차순은 선택한 정렬 키에 따라 올바르게 선택됨에 유의하십시오.

print_stats(*restrictions)

Stats 클래스에 대한 이 메서드는 profile.run() 정의에 설명된 대로 보고서를 인쇄합니다.

인쇄 순서는 객체에서 수행된 마지막 sort_stats() 연산을 기반으로 합니다 (add()와 strip_dirs()의 경고가 적용됩니다).

(있다면) 제공된 인자를 사용하여 목록을 중요한 항목으로 줄일 수 있습니다. 처음에는, 목록이 전체 프로파일링 된 함수 집합이 됩니다. 각 제한(restriction)은 정수(줄 수 선택)나 0.0과 1.0을 포함하고 그사이의 십진 소수(줄의 백분율을 선택), 또는 정규식으로 해석되는 문자열(인쇄되는 표준 이름과 일치하는 패턴)입니다. 여러 제한이 제공되면, 순차적으로 적용됩니다. 예를 들면:

print_stats(.1, 'foo:')

는 먼저 인쇄를 목록의 처음 10%로 제한한 다음, 파일 이름 .*foo:의 일부인 함수만 인쇄합니다. 대조적으로, 명령:

print_stats('foo:', .1)

은 파일 이름이 .*foo: 인 모든 함수로 목록을 제한한 다음, 그중 처음 10%만 인쇄합니다.

print_callers(*restrictions)

Stats 클래스에 대한 이 메서드는 프로파일 된 데이터베이스에 있는 각 함수를 호출한 모든 함수의 목록을 인쇄합니다. 순서는 print_stats()에서 제공한 순서와 동일하며, 제한 인자의 정의도 동일합니다. 각 호출자는 개별 줄로 보고됩니다. 통계를 생성한 프로파일러에 따라 형식이 약간 다릅니다:

profile을 사용하면, 각 호출자 뒤에 숫자가 괄호 안에 표시되어 이 특정 호출이 몇 번이나 되었는지 표시됩니다. 편의를 위해, 두 번째 괄호로 묶지 않은 숫자는 오른쪽에 나오는 함수에서 소비한 누적 시간을 반복합니다.

cProfile을 사용하면, 각 호출자 앞에 세 숫자가 나옵니다: 이 특정 호출이 발생한 횟수, 이 특정 호출자가 호출한 동안 현재 함수에서 소비 한 총 및 누적 시간.

print_callees(*restrictions)

Stats 클래스에 대한 이 메서드는 표시된 함수에 의해 호출된 모든 함수의 목록을 인쇄합니다. 이러한 호출 방향 반전(호출한 대 호출된)을 제외하고, 인자와 순서는 print_callers() 메서드와 같습니다.

get_stats_profile()

이 메서드는 함수 이름을 FunctionProfile 인스턴스로 매핑하는 StatsProfile 인스턴스를 반환합니다. 각 FunctionProfile 인스턴스에는 함수 실행 시간, 호출 횟수 등의 함수의 프로파일 관련 정보가 있습니다.

Added in version 3.9: 다음과 같은 데이터 클래스(dataclasses)를 추가했습니다: StatsProfile, FunctionProfile. 다음과 같은 함수를 추가했습니다: get_stats_profile.

결정론적 프로파일링이란 무엇입니까?

결정론적 프로파일링(Deterministic profiling)이라는 용어는 모든 함수 호출, 함수 반환 및 예외 이벤트가 모니터링되고, (사용자 코드가 실행되는 시간 동안) 이러한 이벤트 사이의 간격에 대한 정확한 시간 측정이 이루어진다는 사실을 반영하기 위한 것입니다. 반면에, 통계적 프로파일링(statistical profiling)(이 모듈에서는 수행하지 않습니다)은 유효 명령어 포인터를 무작위로 샘플링하여 시간이 소비되는 위치를 추론합니다. 후자의 기술은 전통적으로 (코드를 계측할 필요가 없기 때문에) 오버헤드가 적지만, 시간이 어디에서 소비되는지에 대한 상대적 표시만 제공합니다.

파이썬에서는, 실행 중에 인터프리터가 활성화되어있어서, 결정론적 프로파일링을 수행하기 위해 인스트루먼트 된 코드(instrumented code)가 필요하지 않습니다. 파이썬은 각 이벤트에 대해 자동으로 훅(hook)(선택적 콜백)을 제공합니다. 또한, 파이썬의 인터프리터 적인 성격은 실행에 이미 많은 오버헤드를 추가하는 경향이 있어서, 결정론적 프로파일링은 일반적인 응용 프로그램에서 작은 처리 오버헤드만 추가하는 경향이 있습니다. 결과적으로 결정론적 프로파일링은 그다지 비싸지 않으면서도, 파이썬 프로그램의 실행에 대한 광범위한 실행 시간 통계를 제공합니다.

호출 수 통계를 사용하여 코드의 버그(놀랄만한 횟수)를 식별하고, 가능한 인라인 확장 지점(높은 호출 횟수)을 식별할 수 있습니다. 내부 시간 통계를 사용하여 신중하게 최적화해야 하는 “핫 루프(hot loops)”를 식별할 수 있습니다. 누적 시간 통계를 사용하여 알고리즘 선택에서의 고수준 에러를 식별할 수 있습니다. 이 프로파일러에서의 누적 시간의 특이한 처리는 알고리즘의 재귀 구현에 대한 통계를 반복 구현과 직접 비교할 수 있도록 함에 유의하십시오.

한계

타이밍 정보의 정확성과 관련하여 한 가지 제약이 있습니다. 정확성과 관련해서는 결정론적 프로파일러에 근본적인 문제가 있습니다. 가장 명백한 제약은 하부 “시계”가 (일반적으로) 약 .001 초의 속도로만 눈금이 변하는 것입니다. 따라서 하부 시계보다 더 정확한 측정은 없습니다. 충분한 측정을 수행하면, “에러”가 평균이 되어 사라지는 경향이 있습니다. 불행히도, 이 첫 번째 에러를 제거하면 두 번째 에러 원인이 발생합니다.

두 번째 문제는 이벤트가 디스패치 된 시점부터 프로파일러가 시간을 얻기 위해 호출하는 것이 실제로 시계의 상태를 얻기까지 “시간이 걸린다”는 것입니다. 마찬가지로, 프로파일러 이벤트 핸들러를 빠져나갈 때 시계값이 획득된 (그런 다음 저장됩니다) 시간부터, 사용자의 코드가 다시 실행될 때까지 어떤 지연이 발생합니다. 결과적으로, 여러 번 호출되거나, 많은 함수를 호출하는 함수는 일반적으로 이 에러를 누적합니다. 이러한 방식으로 누적되는 에러는 일반적으로 시계 정확도(1 눈금 미만)보다 작지만, 누적될 수 있어서 매우 중요해집니다.

오버헤드가 낮은 cProfile보다 profile에서 이 문제가 더 중요합니다. 이러한 이유로, profile은 특정 플랫폼에 대해 자신을 보정하는 방법을 제공하여 이 에러를 확률적으로 (평균적으로) 제거할 수 있습니다. 프로파일러가 보정된 후에는, 더 정확하지만 (최소한 최소 자승의 의미에서), 때로는 음수를 생성합니다 (호출 횟수가 예외적으로 낮고, 확률의 신들이 당신에게 등을 돌리면 :-). ) 프로파일에서 음수를 보아도 너무 놀라지 마십시오. 프로파일러를 보정한 경우에*만* 나타나야 하며, 결과는 실제로 보정하지 않은 것보다 낫습니다.

보정

profile 모듈의 프로파일러는 각 이벤트 처리 시간에서 상수를 빼서 시간 함수 호출의 오버헤드를 보상하고, 결과를 잘 보관합니다. 기본적으로, 상수는 0입니다. 다음 절차는 주어진 플랫폼에 대해 더 나은 상수를 얻는 데 사용될 수 있습니다 (한계를 참조하십시오).

import profile
pr = profile.Profile()
for i in range(5):
    print(pr.calibrate(10000))

The method executes the number of Python calls given by the argument, directly and again under the profiler, measuring the time for both. It then computes the hidden overhead per profiler event, and returns that as a float. For example, on a 1.8Ghz Intel Core i5 running macOS, and using Python’s time.process_time() as the timer, the magical number is about 4.04e-6.

이 반복의 목적은 상당히 일관된 결과를 얻는 것입니다. 컴퓨터가 매우 빠르거나, 타이머 함수의 해상도가 좋지 않으면, 일관된 결과를 얻기 위해 100000이나 심지어 1000000을 전달해야 할 수 있습니다.

일관된 대답을 얻었을 때, 세 가지 방법으로 사용할 수 있습니다:

import profile

# 1. Apply computed bias to all Profile instances created hereafter.
profile.Profile.bias = your_computed_bias

# 2. Apply computed bias to a specific Profile instance.
pr = profile.Profile()
pr.bias = your_computed_bias

# 3. Specify computed bias in instance constructor.
pr = profile.Profile(bias=your_computed_bias)

선택해야 한다면, 더 작은 상수를 선택하는 것이 좋습니다, 그러면 결과가 프로파일 통계에서 결과가 “덜 자주” 음수로 표시됩니다.

사용자 정의 타이머 사용하기

현재 시각을 결정하는 방법을 변경하려면 (예를 들어, 벽시계 시간이나 소요된 프로세스 시간을 사용하도록 만들려면), Profile 클래스 생성자에게 원하는 타이밍 함수를 전달합니다:

pr = profile.Profile(your_time_func)

결과 프로파일러는 your_time_func를 호출합니다. profile.Profile이나 cProfile.Profile 중 어느 것을 사용하느냐에 따라, your_time_func의 반환 값은 다르게 해석됩니다:

profile.Profile

your_time_func는 단일 숫자를 반환하거나, 또는 (os.times()가 반환하는 것과 같이) 합계가 현재 시각인 숫자 리스트를 반환해야 합니다. 함수가 단일 시간 숫자를 반환하거나, 반환된 숫자의 리스트 길이가 2이면, 특히 빠른 버전의 디스패치 루틴을 얻게 됩니다.

Be warned that you should calibrate the profiler class for the timer function that you choose (see 보정). For most machines, a timer that returns a lone integer value will provide the best results in terms of low overhead during profiling. (os.times() is pretty bad, as it returns a tuple of floating-point values). If you want to substitute a better timer in the cleanest fashion, derive a class and hardwire a replacement dispatch method that best handles your timer call, along with the appropriate calibration constant.

cProfile.Profile

your_time_func는 단일 숫자를 반환해야 합니다. 정수를 반환하면, 시간 단위의 실제 지속 시간을 지정하는 두 번째 인자로 클래스 생성자를 호출할 수도 있습니다. 예를 들어, your_integer_time_func가 밀리초 단위로 측정된 시간을 반환하면, 다음과 같이 Profile 인스턴스를 구성합니다:

pr = cProfile.Profile(your_integer_time_func, 0.001)

As the cProfile.Profile class cannot be calibrated, custom timer functions should be used with care and should be as fast as possible. For the best results with a custom timer, it might be necessary to hard-code it in the C source of the internal _lsprof module.

파이썬 3.3은 time에 프로세스나 벽시계 시간을 정확하게 측정하는 데 사용할 수 있는 몇 가지 새로운 함수를 추가합니다. 예를 들어, time.perf_counter()를 참조하십시오.

timeit — Measure execution time of small code snippets

소스 코드: Lib/timeit.py [https://github.com/python/cpython/tree/main/Lib/timeit.py]

This module provides a simple way to time small bits of Python code. It has both a 명령 줄 인터페이스 as well as a callable one. It avoids a number of common traps for measuring execution times. See also Tim Peters’ introduction to the “Algorithms” chapter in the second edition of Python Cookbook, published by O’Reilly.

기본 예제

다음 예제에서는 명령 줄 인터페이스를 사용하여 세 가지 다른 표현식을 비교하는 방법을 보여줍니다:

$ python -m timeit "'-'.join(str(n) for n in range(100))"
10000 loops, best of 5: 30.2 usec per loop
$ python -m timeit "'-'.join([str(n) for n in range(100)])"
10000 loops, best of 5: 27.5 usec per loop
$ python -m timeit "'-'.join(map(str, range(100)))"
10000 loops, best of 5: 23.2 usec per loop

이것은 파이썬 인터페이스로는 다음과 같이 할 수 있습니다:

>>> import timeit
>>> timeit.timeit('"-".join(str(n) for n in range(100))', number=10000)
0.3018611848820001
>>> timeit.timeit('"-".join([str(n) for n in range(100)])', number=10000)
0.2727368790656328
>>> timeit.timeit('"-".join(map(str, range(100)))', number=10000)
0.23702679807320237

콜러블을 파이썬 인터페이스로 전달할 수도 있습니다:

>>> timeit.timeit(lambda: "-".join(map(str, range(100))), number=10000)
0.19665591977536678

그러나 timeit()은 명령 줄 인터페이스가 사용될 때만 반복 횟수를 자동으로 결정합니다. 예제 절에서 고급 예제를 찾을 수 있습니다.

파이썬 인터페이스

이 모듈은 세 개의 편리 함수와 하나의 공용 클래스를 정의합니다:

timeit.timeit(stmt='pass', setup='pass', timer=<default timer>, number=1000000, globals=None)

지정된 문장, setup 코드 및 timer 함수로 Timer 인스턴스를 만들고, number 실행으로 timeit() 메서드를 실행합니다. 선택적 globals 인자는 코드를 실행할 이름 공간을 지정합니다.

버전 3.5에서 변경: 선택적 globals 매개 변수가 추가되었습니다.

timeit.repeat(stmt='pass', setup='pass', timer=<default timer>, repeat=5, number=1000000, globals=None)

주어진 문장, setup 코드 및 timer 함수로 Timer 인스턴스를 생성하고, 주어진 repeat 카운트와 number 실행으로 repeat() 메서드를 실행합니다. 선택적 globals 인자는 코드를 실행할 이름 공간을 지정합니다.

버전 3.5에서 변경: 선택적 globals 매개 변수가 추가되었습니다.

버전 3.7에서 변경: repeat의 기본값이 3에서 5로 변경되었습니다.

timeit.default_timer()

The default timer, which is always time.perf_counter(), returns float seconds. An alternative, time.perf_counter_ns, returns integer nanoseconds.

버전 3.3에서 변경: 이제 time.perf_counter()가 기본 타이머입니다.

class timeit.Timer(stmt='pass', setup='pass', timer=<timer function>, globals=None)

작은 코드 조각의 실행 속도를 측정하기 위한 클래스.

생성자는 시간 측정될 문장, 설정에 사용되는 추가 문장 및 타이머 함수를 받아들입니다. 두 문장의 기본값은 'pass'입니다; 타이머 함수는 플랫폼에 따라 다릅니다 (모듈 독스트링을 참조하십시오). stmt와 setup은 여러 줄에 걸친 문자열 리터럴을 포함하지 않는 한 ;나 줄 바꿈으로 구분된 여러 개의 문장을 포함 할 수도 있습니다. 문장은 기본적으로 timeit의 이름 공간 내에서 실행됩니다; 이 동작은 globals에 이름 공간을 전달하여 제어 할 수 있습니다.

첫 번째 문장의 실행 시간을 측정하려면, timeit() 메서드를 사용하십시오. repeat()와 autorange() 메서드는 timeit()을 여러 번 호출하는 편리 메서드입니다.

setup의 실행 시간은 전체 측정 실행 시간에서 제외됩니다.

stmt와 setup 매개 변수는 인자 없이 호출 할 수 있는 객체를 받아들일 수도 있습니다. 이렇게 하면 timeit()에 의해 실행될 타이머 함수에 그들에 대한 호출을 포함시킵니다. 이때는 여분의 함수 호출로 인해 타이밍 오버헤드가 약간 더 커집니다.

버전 3.5에서 변경: 선택적 globals 매개 변수가 추가되었습니다.

timeit(number=1000000)

Time number executions of the main statement. This executes the setup statement once, and then returns the time it takes to execute the main statement a number of times. The default timer returns seconds as a float. The argument is the number of times through the loop, defaulting to one million. The main statement, the setup statement and the timer function to be used are passed to the constructor.

참고

기본적으로, timeit()은 시간 측정 중에 가비지 수거를 일시적으로 끕니다. 이 방법의 장점은 독립적인 시간 측정이 더 잘 비교될 수 있다는 것입니다. 단점은 GC가 측정되는 함수의 성능에서 중요한 요소가 될 수 있다는 것입니다. 그렇다면, GC를 setup 문자열의 첫 번째 문장에서 다시 활성화할 수 있습니다. 예를 들면:

timeit.Timer('for i in range(10): oct(i)', 'gc.enable()').timeit()

autorange(callback=None)

timeit()를 호출하는 횟수를 자동으로 결정합니다.

This is a convenience function that calls timeit() repeatedly so that the total time >= 0.2 second, returning the eventual (number of loops, time taken for that number of loops). It calls timeit() with increasing numbers from the sequence 1, 2, 5, 10, 20, 50, … until the time taken is at least 0.2 seconds.

callback이 주어지고 None이 아니면, 각 시도 다음에 두 개의 인자로 호출합니다: callback(number, time_taken).

Added in version 3.6.

repeat(repeat=5, number=1000000)

timeit()을 몇 번 호출합니다.

이것은 반복적으로 timeit()을 호출하여 결과 리스트를 반환하는 편리 함수입니다. 첫 번째 인자는 timeit()을 호출할 횟수를 지정합니다. 두 번째 인자는 timeit()에 대한 number 인자를 지정합니다.

참고

결과 벡터로부터 평균과 표준 편차를 계산하고 이를 보고하고 싶을 수 있습니다. 하지만, 이것은 별로 유용하지 않습니다. 일반적으로, 가장 낮은 값이 여러분의 기계가 주어진 코드 조각을 얼마나 빨리 실행할 수 있는지에 대한 하한값을 제공합니다; 결과 벡터의 더 높은 값은 일반적으로 파이썬의 속도 변동성 때문이 아니라, 시간 측정의 정확성을 방해하는 다른 프로세스에 의해 발생합니다. 따라서 결과의 min()이 여러분이 관심을 기울여야 할 유일한 숫자일 것입니다. 그 후에, 전체 벡터를 살펴보고 통계보다는 상식을 적용해야 합니다.

버전 3.7에서 변경: repeat의 기본값이 3에서 5로 변경되었습니다.

print_exc(file=None)

측정되는 코드로부터의 트레이스백을 인쇄하는 도우미.

일반적인 사용:

t = Timer(...)       # outside the try/except
try:
    t.timeit(...)    # or t.repeat(...)
except Exception:
    t.print_exc()

표준 트레이스백에 비해 장점은 컴파일된 템플릿의 소스 행이 표시된다는 것입니다. 선택적 file 인자는 트레이스백을 보내야 할 곳을 지시합니다; 기본값은 sys.stderr입니다.

명령 줄 인터페이스

명령 줄에서 프로그램으로 호출할 때, 다음 형식이 사용됩니다:

python -m timeit [-n N] [-r N] [-u U] [-s S] [-p] [-v] [-h] [statement ...]

이때 다음 옵션을 지원합니다:

-n N, --number=N

‘statement’를 실행하는 횟수

-r N, --repeat=N

타이머 반복 횟수 (기본값 5)

-s S, --setup=S

초기에 한 번 실행될 문장 (기본값 pass)

-p, --process

벽시계 시간이 아니라 프로세스 시간을 측정합니다, 기본값인 time.perf_counter() 대신 time.process_time()을 사용합니다

Added in version 3.3.

-u, --unit=U

specify a time unit for timer output; can select nsec, usec, msec, or sec

Added in version 3.5.

-v, --verbose

날 시간 측정 결과를 인쇄합니다; 더 많은 자릿수 정밀도를 위해서는 반복하십시오

-h, --help

짧은 사용법 메시지를 출력하고 종료합니다

여러 줄의 문장은 각 줄을 별도의 statement 인자로 지정하여 제공할 수 있습니다; 들여쓰기 된 줄은 인자를 따옴표로 묶고 선행 공백을 사용하면 됩니다. 여러 개의 -s 옵션도 비슷하게 취급됩니다.

-n이 주어지지 않으면, 총 시간이 최소 0.2초가 될 때까지 시퀀스 1, 2, 5, 10, 20, 50, … 에서 증가하는 숫자를 시도하여 적절한 루프 수가 계산됩니다.

default_timer() 측정은 같은 기계에서 실행되는 다른 프로그램의 영향을 받을 수 있으므로, 정확한 시간 측정이 필요할 때 가장 좋은 방법은 시간 측정을 몇 번 반복하고 가장 좋은 시간을 사용하는 것입니다. 이 작업에는 -r 옵션이 좋습니다; 대부분의 경우 기본값인 5번 반복으로 충분할 것입니다. time.process_time()을 사용하여 CPU 시간을 측정 할 수 있습니다.

참고

pass 문을 실행하는 것과 관련된 어떤 기준 오버헤드가 있습니다. 여기에 있는 코드는 그것을 숨기려고 시도하지는 않지만, 여러분은 신경 써야 합니다. 기준 오버헤드는 인자 없이 프로그램을 호출하여 측정 할 수 있으며, 파이썬 버전마다 다를 수 있습니다.

예제

처음에 한 번만 실행되는 setup 문을 제공 할 수 있습니다:

$ python -m timeit -s "text = 'sample string'; char = 'g'" "char in text"
5000000 loops, best of 5: 0.0877 usec per loop
$ python -m timeit -s "text = 'sample string'; char = 'g'" "text.find(char)"
1000000 loops, best of 5: 0.342 usec per loop

In the output, there are three fields. The loop count, which tells you how many times the statement body was run per timing loop repetition. The repetition count (‘best of 5’) which tells you how many times the timing loop was repeated, and finally the time the statement body took on average within the best repetition of the timing loop. That is, the time the fastest repetition took divided by the loop count.

>>> import timeit
>>> timeit.timeit('char in text', setup='text = "sample string"; char = "g"')
0.41440500499993504
>>> timeit.timeit('text.find(char)', setup='text = "sample string"; char = "g"')
1.7246671520006203

Timer 클래스와 그 메서드를 사용하여 같은 작업을 수행 할 수 있습니다:

>>> import timeit
>>> t = timeit.Timer('char in text', setup='text = "sample string"; char = "g"')
>>> t.timeit()
0.3955516149999312
>>> t.repeat()
[0.40183617287970225, 0.37027556854118704, 0.38344867356679524, 0.3712595970846668, 0.37866875250654886]

다음 예제는 여러 줄을 포함하는 표현식의 시간을 측정하는 방법을 보여줍니다. 여기서 우리는 누락되었거나 존재하는 객체 어트리뷰트를 검사하는데 hasattr()과 try/except를 사용하는 비용을 비교합니다:

$ python -m timeit "try:" "  str.__bool__" "except AttributeError:" "  pass"
20000 loops, best of 5: 15.7 usec per loop
$ python -m timeit "if hasattr(str, '__bool__'): pass"
50000 loops, best of 5: 4.26 usec per loop

$ python -m timeit "try:" "  int.__bool__" "except AttributeError:" "  pass"
200000 loops, best of 5: 1.43 usec per loop
$ python -m timeit "if hasattr(int, '__bool__'): pass"
100000 loops, best of 5: 2.23 usec per loop

>>> import timeit
>>> # attribute is missing
>>> s = """\
... try:
...     str.__bool__
... except AttributeError:
...     pass
... """
>>> timeit.timeit(stmt=s, number=100000)
0.9138244460009446
>>> s = "if hasattr(str, '__bool__'): pass"
>>> timeit.timeit(stmt=s, number=100000)
0.5829014980008651
>>>
>>> # attribute is present
>>> s = """\
... try:
...     int.__bool__
... except AttributeError:
...     pass
... """
>>> timeit.timeit(stmt=s, number=100000)
0.04215312199994514
>>> s = "if hasattr(int, '__bool__'): pass"
>>> timeit.timeit(stmt=s, number=100000)
0.08588060699912603

timeit 모듈이 여러분이 정의한 함수에 액세스하도록 하려면, import 문이 포함된 setup 매개 변수를 전달하면 됩니다:

def test():
    """Stupid test function"""
    L = [i for i in range(100)]

if __name__ == '__main__':
    import timeit
    print(timeit.timeit("test()", setup="from __main__ import test"))

또 다른 옵션은 globals()를 globals 매개 변수로 전달해서, 여러분의 현재 전역 이름 공간에서 코드가 실행되도록 하는 것입니다. 임포트를 개별적으로 지정하는 것보다 편리 할 수 있습니다:

def f(x):
    return x**2
def g(x):
    return x**4
def h(x):
    return x**8

import timeit
print(timeit.timeit('[func(42) for func in (f,g,h)]', globals=globals()))

trace — Trace or track Python statement execution

소스 코드: Lib/trace.py [https://github.com/python/cpython/tree/main/Lib/trace.py]

trace 모듈을 사용하면 프로그램 실행을 추적하고, 주석 처리된 문장 커버리지 리스트를 생성하고, 호출자/피호출자 관계를 인쇄하고, 프로그램 실행 중 호출되는 함수를 나열할 수 있습니다. 다른 프로그램이나 명령 줄에서 사용할 수 있습니다.

더 보기

Coverage.py [https://coverage.readthedocs.io/]

브랜치 커버리지와 같은 고급 기능과 함께 HTML 출력을 제공하는 널리 사용되는 제삼자 커버리지 도구.

명령 줄 사용법

trace 모듈은 명령 줄에서 호출할 수 있습니다. 다음과 같이 간단할 수도 있습니다

python -m trace --count -C . somefile.py ...

이것은 somefile.py를 실행하고 실행 중에 임포트 한 모든 파이썬 모듈들의 주석이 달린 리스트를 현재 디렉터리에 생성합니다.

--help

사용법을 표시하고 종료합니다.

--version

모듈의 버전을 표시하고 종료합니다.

Added in version 3.8: 실행 가능한 모듈을 실행할 수 있는 --module 옵션이 추가되었습니다.

주요 옵션

trace를 호출할 때 다음 옵션 중 적어도 하나를 지정해야 합니다. --listfuncs 옵션은 --trace 나 --count 옵션과 함께 사용할 수 없습니다. --listfuncs이 제공되면, --count 나 --trace는 허용되지 않으며, 반대의 경우도 마찬가지입니다.

-c, --count

프로그램 완료 시 각 문장이 실행된 횟수를 보여주는 주석이 달린 리스팅 파일 집합을 생성합니다. 아래의 --coverdir, --file 및 --no-report도 참조하십시오.

-t, --trace

줄이 실행될 때마다 표시합니다.

-l, --listfuncs

프로그램을 실행하여 실행되는 함수들을 표시합니다.

-r, --report

--count 와 --file 옵션을 사용한 이전 프로그램 실행에서 주석이 달린 목록을 생성합니다. 이것은 어떤 코드도 실행하지 않습니다.

-T, --trackcalls

프로그램을 실행하여 노출된 호출 관계를 표시합니다.

수정자

-f, --file=<file>

여러 추적 실행에서 실행 횟수를 누적할 파일의 이름. --count 옵션과 함께 사용해야 합니다.

-C, --coverdir=<dir>

보고서 파일이 저장되는 디렉터리. package.module에 대한 커버리지 보고서는 dir/package/module.cover 파일에 기록됩니다.

-m, --missing

주석이 달린 리스팅을 작성할 때, >>>>>>로 실행되지 않은 줄을 표시합니다.

-s, --summary

--count 나 --report를 사용할 때, 처리된 각 파일에 대한 요약을 표준출력으로 기록합니다.

-R, --no-report

주석이 달린 리스팅을 생성하지 않습니다. 이것은 --count를 사용하여 여러 번 실행한 다음, 마지막에 주석이 달린 리스팅의 단일 집합을 생성하려고 할 때 유용합니다.

-g, --timing

프로그램이 시작된 이후의 시간을 각 줄 앞에 붙입니다. 추적하는 동안에만 사용됩니다.

필터

이 옵션들은 여러 번 반복 될 수 있습니다.

--ignore-module=<mod>

주어진 각 모듈 이름과 (패키지라면) 그 서브 모듈을 무시합니다. 인자는 쉼표로 구분된 이름 목록일 수 있습니다.

--ignore-dir=<dir>

명명된 디렉터리와 하위 디렉터리의 모든 모듈과 패키지를 무시합니다. 인자는 os.pathsep으로 구분된 디렉터리 목록일 수 있습니다.

프로그래밍 인터페이스

class trace.Trace(count=1, trace=1, countfuncs=0, countcallers=0, ignoremods=(), ignoredirs=(), infile=None, outfile=None, timing=False)

단일 문장이나 표현식의 실행을 추적할 객체를 만듭니다. 모든 매개 변수는 선택 사항입니다. count는 줄 번호의 카운팅을 활성화합니다. trace는 줄 실행 추적을 활성화합니다. countfuncs는 실행 중에 호출된 함수들의 리스팅을 활성화합니다. countcallers는 호출 관계 추적을 활성화합니다. ignoremods는 무시할 모듈이나 패키지의 리스트입니다. ignoredirs는 들어있는 모듈이나 패키지를 무시해야 하는 디렉터리의 리스트입니다. infile은 저장된 카운트 정보를 읽을 파일 이름입니다. outfile는 갱신된 카운트 정보를 쓰는 파일의 이름입니다. timing는 추적이 시작될 때에 상대적인 타임스탬프 표시를 활성화합니다.

run(cmd)

명령을 실행하고 현재 추적 매개 변수를 사용하여 실행에서 통계를 수집합니다. cmd는 exec()로 전달하는데 적합한 문자열이나 코드 객체여야 합니다.

runctx(cmd, globals=None, locals=None)

정의된 전역과 지역 환경에서, 명령을 실행하고 현재 추적 매개 변수를 사용하여 실행에서 통계를 수집합니다. 정의되지 않으면, globals 와 locals의 기본값은 빈 딕셔너리입니다.

runfunc(func, /, *args, **kwds)

현재 추적 매개 변수를 갖는 Trace 객체의 제어하에 주어진 인자로 func를 호출합니다.

results()

주어진 Trace 인스턴스에 대한 모든 이전 run, runctx 및 runfunc 호출의 누적 결과를 포함하는 CoverageResults 객체를 반환합니다. 누적된 추적 결과를 재설정하지 않습니다.

class trace.CoverageResults

Trace.results()에 의해 만들어진 커버리지 결과를 위한 컨테이너. 사용자가 직접 만들어서는 안 됩니다.

update(other)

다른 CoverageResults 객체의 데이터를 병합합니다.

write_results(show_missing=True, summary=False, coverdir=None, *, ignore_missing_files=False)

커버리지 결과를 기록합니다. 실행 카운트가 없는 줄을 표시하려면 show_missing을 설정하십시오. 모듈당 커버리지 요약을 출력에 포함 시키려면 summary를 설정하십시오. coverdir은 커버리지 결과 파일이 출력될 디렉터리를 지정합니다. None이면, 각 소스 파일의 결과가 해당 디렉터리에 위치합니다.

If ignore_missing_files is True, coverage counts for files that no longer exist are silently ignored. Otherwise, a missing file will raise a FileNotFoundError.

버전 3.13에서 변경: Added ignore_missing_files parameter.

프로그래밍 인터페이스의 사용을 보여주는 간단한 예제:

import sys
import trace

# create a Trace object, telling it what to ignore, and whether to
# do tracing or line-counting or both.
tracer = trace.Trace(
    ignoredirs=[sys.prefix, sys.exec_prefix],
    trace=0,
    count=1)

# run the new command using the given tracer
tracer.run('main()')

# make a report, placing output in the current directory
r = tracer.results()
r.write_results(show_missing=True, coverdir=".")

tracemalloc — Trace memory allocations

Added in version 3.4.

소스 코드: Lib/tracemalloc.py [https://github.com/python/cpython/tree/main/Lib/tracemalloc.py]

tracemalloc 모듈은 파이썬이 할당한 메모리 블록을 추적하는 디버그 도구입니다. 다음 정보를 제공합니다:

객체가 할당된 곳의 트레이스백

파일명과 줄 번호별로 할당된 메모리 블록에 대한 통계: 할당된 메모리 블록의 총 크기, 수 및 평균 크기

메모리 누수를 탐지하기 위해 두 스냅샷의 차이점 계산

파이썬이 할당한 대부분의 메모리 블록을 추적하려면, PYTHONTRACEMALLOC 환경 변수를 1로 설정하거나, -X tracemalloc 명령 줄 옵션을 사용하여 모듈을 가능한 한 빨리 시작해야 합니다. tracemalloc.start() 함수는 실행 시간에 호출되어 파이썬 메모리 할당 추적을 시작할 수 있습니다.

기본적으로, 할당된 메모리 블록의 트레이스는 가장 최근의 프레임 만 저장합니다 (1프레임). 시작 시 25프레임을 저장하려면: PYTHONTRACEMALLOC 환경 변수를 25로 설정하거나, -X tracemalloc=25 명령 줄 옵션을 사용하십시오.

예

상위 10개 표시

가장 많은 메모리를 할당하는 10개의 파일을 표시합니다:

import tracemalloc

tracemalloc.start()

# ... run your application ...

snapshot = tracemalloc.take_snapshot()
top_stats = snapshot.statistics('lineno')

print("[ Top 10 ]")
for stat in top_stats[:10]:
    print(stat)

파이썬 테스트 스위트의 출력 예:

[ Top 10 ]
<frozen importlib._bootstrap>:716: size=4855 KiB, count=39328, average=126 B
<frozen importlib._bootstrap>:284: size=521 KiB, count=3199, average=167 B
/usr/lib/python3.4/collections/__init__.py:368: size=244 KiB, count=2315, average=108 B
/usr/lib/python3.4/unittest/case.py:381: size=185 KiB, count=779, average=243 B
/usr/lib/python3.4/unittest/case.py:402: size=154 KiB, count=378, average=416 B
/usr/lib/python3.4/abc.py:133: size=88.7 KiB, count=347, average=262 B
<frozen importlib._bootstrap>:1446: size=70.4 KiB, count=911, average=79 B
<frozen importlib._bootstrap>:1454: size=52.0 KiB, count=25, average=2131 B
<string>:5: size=49.7 KiB, count=148, average=344 B
/usr/lib/python3.4/sysconfig.py:411: size=48.0 KiB, count=1, average=48.0 KiB

파이썬이 모듈에서 4855 KiB 데이터 (바이트 코드와 상수)를 로드했으며 collections 모듈이 namedtuple 형을 빌드하기 위해 244 KiB를 할당했음을 알 수 있습니다.

추가 옵션은 Snapshot.statistics()를 참조하십시오.

차이 계산

두 개의 스냅샷을 취하고 차이점을 표시합니다:

import tracemalloc
tracemalloc.start()
# ... start your application ...

snapshot1 = tracemalloc.take_snapshot()
# ... call the function leaking memory ...
snapshot2 = tracemalloc.take_snapshot()

top_stats = snapshot2.compare_to(snapshot1, 'lineno')

print("[ Top 10 differences ]")
for stat in top_stats[:10]:
    print(stat)

파이썬 테스트 스위트의 일부 테스트를 실행하기 전/후의 출력 예:

[ Top 10 differences ]
<frozen importlib._bootstrap>:716: size=8173 KiB (+4428 KiB), count=71332 (+39369), average=117 B
/usr/lib/python3.4/linecache.py:127: size=940 KiB (+940 KiB), count=8106 (+8106), average=119 B
/usr/lib/python3.4/unittest/case.py:571: size=298 KiB (+298 KiB), count=589 (+589), average=519 B
<frozen importlib._bootstrap>:284: size=1005 KiB (+166 KiB), count=7423 (+1526), average=139 B
/usr/lib/python3.4/mimetypes.py:217: size=112 KiB (+112 KiB), count=1334 (+1334), average=86 B
/usr/lib/python3.4/http/server.py:848: size=96.0 KiB (+96.0 KiB), count=1 (+1), average=96.0 KiB
/usr/lib/python3.4/inspect.py:1465: size=83.5 KiB (+83.5 KiB), count=109 (+109), average=784 B
/usr/lib/python3.4/unittest/mock.py:491: size=77.7 KiB (+77.7 KiB), count=143 (+143), average=557 B
/usr/lib/python3.4/urllib/parse.py:476: size=71.8 KiB (+71.8 KiB), count=969 (+969), average=76 B
/usr/lib/python3.4/contextlib.py:38: size=67.2 KiB (+67.2 KiB), count=126 (+126), average=546 B

우리는 파이썬이 8173 KiB의 모듈 데이터(바이트 코드와 상수)를 로드했으며, 이전 스냅샷을 취할 때인 테스트 전에 로드된 것보다 4428 KiB 더 많은 것을 볼 수 있습니다. 마찬가지로, linecache 모듈은 트레이스백을 포맷하기 위해 940 KiB의 파이썬 소스 코드를 캐시 했는데, 이전 스냅샷 이후의 모든 것입니다.

시스템에 사용 가능한 메모리가 거의 없으면, 스냅샷을 오프라인으로 분석하기 위해 Snapshot.dump() 메서드로 디스크에 스냅샷을 기록할 수 있습니다. 그런 다음 Snapshot.load() 메서드를 사용하여 스냅샷을 다시 로드하십시오.

메모리 블록의 트레이스백 얻기

가장 큰 메모리 블록의 트레이스백을 표시하는 코드:

import tracemalloc

# Store 25 frames
tracemalloc.start(25)

# ... run your application ...

snapshot = tracemalloc.take_snapshot()
top_stats = snapshot.statistics('traceback')

# pick the biggest memory block
stat = top_stats[0]
print("%s memory blocks: %.1f KiB" % (stat.count, stat.size / 1024))
for line in stat.traceback.format():
    print(line)

파이썬 테스트 스위트의 출력 예 (트레이스백은 25프레임으로 제한되었습니다):

903 memory blocks: 870.1 KiB
  File "<frozen importlib._bootstrap>", line 716
  File "<frozen importlib._bootstrap>", line 1036
  File "<frozen importlib._bootstrap>", line 934
  File "<frozen importlib._bootstrap>", line 1068
  File "<frozen importlib._bootstrap>", line 619
  File "<frozen importlib._bootstrap>", line 1581
  File "<frozen importlib._bootstrap>", line 1614
  File "/usr/lib/python3.4/doctest.py", line 101
    import pdb
  File "<frozen importlib._bootstrap>", line 284
  File "<frozen importlib._bootstrap>", line 938
  File "<frozen importlib._bootstrap>", line 1068
  File "<frozen importlib._bootstrap>", line 619
  File "<frozen importlib._bootstrap>", line 1581
  File "<frozen importlib._bootstrap>", line 1614
  File "/usr/lib/python3.4/test/support/__init__.py", line 1728
    import doctest
  File "/usr/lib/python3.4/test/test_pickletools.py", line 21
    support.run_doctest(pickletools)
  File "/usr/lib/python3.4/test/regrtest.py", line 1276
    test_runner()
  File "/usr/lib/python3.4/test/regrtest.py", line 976
    display_failure=not verbose)
  File "/usr/lib/python3.4/test/regrtest.py", line 761
    match_tests=ns.match_tests)
  File "/usr/lib/python3.4/test/regrtest.py", line 1563
    main()
  File "/usr/lib/python3.4/test/__main__.py", line 3
    regrtest.main_in_temp_cwd()
  File "/usr/lib/python3.4/runpy.py", line 73
    exec(code, run_globals)
  File "/usr/lib/python3.4/runpy.py", line 160
    "__main__", fname, loader, pkg_name)

대부분의 메모리가 모듈에서 데이터(바이트 코드와 상수)를 로드하기 위해 importlib 모듈에 할당되었음을 알 수 있습니다: 870.1 KiB. 트레이스백은 importlib가 가장 최근에 데이터를 로드한 위치입니다: doctest 모듈의 import pdb 줄. 새 모듈이 로드되면 트레이스백이 변경될 수 있습니다.

예쁜 탑(top)

<frozen importlib._bootstrap>과 <unknown> 파일을 무시하고, 예쁜 출력으로 가장 많은 메모리를 할당하는 10개의 줄을 표시하는 코드:

import linecache
import os
import tracemalloc

def display_top(snapshot, key_type='lineno', limit=10):
    snapshot = snapshot.filter_traces((
        tracemalloc.Filter(False, "<frozen importlib._bootstrap>"),
        tracemalloc.Filter(False, "<unknown>"),
    ))
    top_stats = snapshot.statistics(key_type)

    print("Top %s lines" % limit)
    for index, stat in enumerate(top_stats[:limit], 1):
        frame = stat.traceback[0]
        print("#%s: %s:%s: %.1f KiB"
              % (index, frame.filename, frame.lineno, stat.size / 1024))
        line = linecache.getline(frame.filename, frame.lineno).strip()
        if line:
            print('    %s' % line)

    other = top_stats[limit:]
    if other:
        size = sum(stat.size for stat in other)
        print("%s other: %.1f KiB" % (len(other), size / 1024))
    total = sum(stat.size for stat in top_stats)
    print("Total allocated size: %.1f KiB" % (total / 1024))

tracemalloc.start()

# ... run your application ...

snapshot = tracemalloc.take_snapshot()
display_top(snapshot)

파이썬 테스트 스위트의 출력 예:

Top 10 lines
#1: Lib/base64.py:414: 419.8 KiB
    _b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
#2: Lib/base64.py:306: 419.8 KiB
    _a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
#3: collections/__init__.py:368: 293.6 KiB
    exec(class_definition, namespace)
#4: Lib/abc.py:133: 115.2 KiB
    cls = super().__new__(mcls, name, bases, namespace)
#5: unittest/case.py:574: 103.1 KiB
    testMethod()
#6: Lib/linecache.py:127: 95.4 KiB
    lines = fp.readlines()
#7: urllib/parse.py:476: 71.8 KiB
    for a in _hexdig for b in _hexdig}
#8: <string>:5: 62.0 KiB
#9: Lib/_weakrefset.py:37: 60.0 KiB
    self.data = set()
#10: Lib/base64.py:142: 59.8 KiB
    _b32tab2 = [a + b for a in _b32tab for b in _b32tab]
6220 other: 3602.8 KiB
Total allocated size: 5303.1 KiB

추가 옵션은 Snapshot.statistics()를 참조하십시오.

모든 추적한 메모리 블록의 현재 및 최대 크기를 기록

다음 코드는 0 + 1 + 2 + ...와 같은 두 개의 합계를 비효율적으로 계산하는데, 이 숫자들의 리스트를 만듭니다. 이 리스트는 일시적으로 많은 메모리를 소비합니다. get_traced_memory()와 reset_peak()를 사용하여 계산 중 최대 메모리 사용량뿐만 아니라 합이 계산된 후의 작은 메모리 사용량도 관찰할 수 있습니다:

import tracemalloc

tracemalloc.start()

# Example code: compute a sum with a large temporary list
large_sum = sum(list(range(100000)))

first_size, first_peak = tracemalloc.get_traced_memory()

tracemalloc.reset_peak()

# Example code: compute a sum with a small temporary list
small_sum = sum(list(range(1000)))

second_size, second_peak = tracemalloc.get_traced_memory()

print(f"{first_size=}, {first_peak=}")
print(f"{second_size=}, {second_peak=}")

출력:

first_size=664, first_peak=3592984
second_size=804, second_peak=29704

reset_peak()를 사용하면 small_sum을 계산하는 동안의 최대 사용량을 start() 호출 이후 메모리 블록의 전체 최대 크기보다 훨씬 작더라도 정확하게 기록 할 수 있습니다. reset_peak()를 호출하지 않으면, second_peak는 여전히 large_sum 계산의 최대가 됩니다 (즉, first_peak와 같습니다). 이 경우, 두 최댓값은 모두 최종 메모리 사용량보다 훨씬 높아서, 최적화할 수 있음을 제안합니다 (list에 대한 불필요한 호출을 제거하고, sum(range(...))이라고 작성하여).

API

함수

tracemalloc.clear_traces()

파이썬이 할당한 메모리 블록의 트레이스를 지웁니다.

stop()도 참조하십시오.

tracemalloc.get_object_traceback(obj)

파이썬 객체 obj가 할당된 위치의 트레이스백을 가져옵니다. Traceback 인스턴스를 반환하거나, tracemalloc 모듈이 메모리 할당을 추적하지 않고 있거나 객체 할당을 추적하지 않았으면 None을 반환합니다.

gc.get_referrers()와 sys.getsizeof() 함수도 참조하십시오.

tracemalloc.get_traceback_limit()

트레이스의 트레이스백에 저장된 최대 프레임 수를 가져옵니다.

한계를 얻으려면 tracemalloc 모듈이 메모리 할당을 추적하고 있어야 합니다, 그렇지 않으면 예외가 발생합니다.

한계는 start() 함수에 의해 설정됩니다.

tracemalloc.get_traced_memory()

tracemalloc 모듈이 추적하는 메모리 블록의 현재 크기와 최대 크기를 튜플로 가져옵니다: (current: int, peak: int).

tracemalloc.reset_peak()

tracemalloc 모듈이 추적하는 메모리 블록의 최대 크기를 현재 크기로 설정합니다.

tracemalloc 모듈이 파이썬 메모리 할당을 추적하고 있지 않으면 아무것도 하지 않습니다.

이 함수는 기록된 최대 크기만 수정하며, clear_traces()와 달리 어떤 추적도 수정하거나 지우지 않습니다. reset_peak()를 호출하기 전에 take_snapshot()로 찍은 스냅숏은 호출 후 찍은 스냅숏과 의미 있게 비교할 수 있습니다.

get_traced_memory()도 참조하십시오.

Added in version 3.9.

tracemalloc.get_tracemalloc_memory()

메모리 블록의 트레이스를 저장하는 데 사용된 tracemalloc 모듈의 메모리 사용량을 바이트 단위로 가져옵니다. int를 반환합니다.

tracemalloc.is_tracing()

tracemalloc 모듈이 파이썬 메모리 할당을 추적하고 있으면 True, 그렇지 않으면 False.

start()와 stop() 함수도 참조하십시오.

tracemalloc.start(nframe: int = 1)

파이썬 메모리 할당 추적을 시작합니다: 파이썬 메모리 할당자(allocator)에 훅을 설치합니다. 수집된 트레이스의 트레이스백은 nframe 개의 프레임으로 제한됩니다. 기본적으로, 메모리 블록의 트레이스는 가장 최근의 프레임 만 저장합니다: 제한은 1입니다. nframe은 1보다 크거나 같아야 합니다.

Traceback.total_nframe 어트리뷰트를 보면 트레이스백을 구성한 원래의 총 프레임 수를 계속 읽을 수 있습니다.

1개보다 더 많은 프레임을 저장하는 것은 'traceback'으로 그룹화된 통계를 계산하거나 누적 통계를 계산할 때만 유용합니다: Snapshot.compare_to()와 Snapshot.statistics() 메서드를 참조하십시오.

더 많은 프레임을 저장하면 tracemalloc 모듈의 메모리와 CPU 오버헤드가 증가합니다. get_tracemalloc_memory() 함수를 사용하여 tracemalloc 모듈이 사용하는 메모리양을 측정하십시오.

PYTHONTRACEMALLOC 환경 변수(PYTHONTRACEMALLOC=NFRAME)와 -X tracemalloc=NFRAME 명령 줄 옵션을 사용하여 시작 시 추적을 시작할 수 있습니다.

stop(), is_tracing() 및 get_traceback_limit() 함수도 참조하십시오.

tracemalloc.stop()

파이썬 메모리 할당 추적을 중지합니다: 파이썬 메모리 할당자에서 훅을 제거합니다. 또한 파이썬이 할당한 메모리 블록의 이전에 수집된 모든 트레이스를 지웁니다.

트레이스를 지우기 전에 take_snapshot() 함수를 호출하여 트레이스의 스냅샷을 취하십시오.

start(), is_tracing() 및 clear_traces() 함수도 참조하십시오.

tracemalloc.take_snapshot()

파이썬이 할당한 메모리 블록의 트레이스의 스냅샷을 취합니다. 새로운 Snapshot 인스턴스를 반환합니다.

tracemalloc 모듈이 메모리 할당 추적을 시작하기 전에 할당된 메모리 블록은 스냅샷에 포함되지 않습니다.

트레이스의 트레이스백은 get_traceback_limit() 개의 프레임으로 제한됩니다. 더 많은 프레임을 저장하려면 start() 함수의 nframe 매개 변수를 사용하십시오.

스냅샷을 취하기 위해서는 tracemalloc 모듈이 메모리 할당을 추적하고 있어야 합니다, start() 함수를 참조하십시오.

get_object_traceback() 함수도 참조하십시오.

DomainFilter

class tracemalloc.DomainFilter(inclusive: bool, domain: int)

주소 공간(도메인)별로 메모리 블록의 트레이스를 필터링합니다.

Added in version 3.6.

inclusive

inclusive가 True이면 (포함), 주소 공간 domain에 할당된 메모리 블록을 일치시킵니다.

inclusive가 False이면 (제외), 주소 공간 domain에 할당되지 않은 메모리 블록을 일치시킵니다.

domain

메모리 블록의 주소 공간 (int). 읽기 전용 프로퍼티.

Filter

class tracemalloc.Filter(inclusive: bool, filename_pattern: str, lineno: int = None, all_frames: bool = False, domain: int = None)

메모리 블록의 트레이스를 필터링합니다.

filename_pattern의 문법은 fnmatch.fnmatch() 함수를 참조하십시오. '.pyc' 파일 확장자가 '.py'로 대체됩니다.

예:

Filter(True, subprocess.__file__)은 subprocess 모듈의 트레이스만 포함합니다

Filter(False, tracemalloc.__file__)은 tracemalloc 모듈의 트레이스를 제외합니다

Filter(False, "<unknown>")은 빈 트레이스백을 제외합니다

버전 3.5에서 변경: '.pyo' 파일 확장자는 더는 '.py'로 대체되지 않습니다.

버전 3.6에서 변경: domain 어트리뷰트를 추가했습니다.

domain

메모리 블록의 주소 공간 (int나 None).

tracemalloc은 도메인 0을 사용하여 파이썬의 메모리 할당을 추적합니다. C 확장은 다른 도메인을 사용하여 다른 리소스를 추적 할 수 있습니다.

inclusive

inclusive가 True(포함)이면, 줄 번호 lineno에서 이름이 filename_pattern과 일치하는 파일에서 할당된 메모리 블록만 일치시킵니다.

inclusive가 False(제외)이면, 줄 번호 lineno에서 이름이 filename_pattern과 일치하는 파일에 할당된 메모리 블록을 무시합니다.

lineno

필터의 줄 번호 (int). lineno가 None이면, 필터는 모든 줄 번호와 일치합니다.

filename_pattern

필터의 파일명 패턴 (str). 읽기 전용 프로퍼티.

all_frames

all_frames가 True이면, 트레이스백의 모든 프레임이 검사됩니다. all_frames가 False이면, 가장 최근 프레임 만 검사됩니다.

트레이스백 한계가 1이면 이 어트리뷰트가 적용되지 않습니다. get_traceback_limit() 함수와 Snapshot.traceback_limit 어트리뷰트를 참조하십시오.

Frame

class tracemalloc.Frame

트레이스백의 프레임.

Traceback 클래스는 Frame 인스턴스의 시퀀스입니다.

filename

파일명 (str).

lineno

줄 번호 (int).

Snapshot

class tracemalloc.Snapshot

파이썬이 할당한 메모리 블록의 트레이스의 스냅샷.

take_snapshot() 함수는 스냅샷 인스턴스를 만듭니다.

compare_to(old_snapshot: Snapshot, key_type: str, cumulative: bool = False)

이전 스냅샷과의 차이점을 계산합니다. key_type 별로 그룹화된 StatisticDiff 인스턴스의 정렬된 리스트로 통계를 가져옵니다.

key_type과 cumulative 매개 변수에 대해서는 Snapshot.statistics() 메서드를 참조하십시오.

결과는 다음 값에 따라 내림차순으로 정렬됩니다: StatisticDiff.size_diff의 절댓값, StatisticDiff.size, StatisticDiff.count_diff의 절댓값, Statistic.count 그런 다음 StatisticDiff.traceback.

dump(filename)

스냅샷을 파일에 씁니다.

스냅샷을 다시 로드하려면 load()를 사용하십시오.

filter_traces(filters)

필터링 된 traces 시퀀스로 새 Snapshot 인스턴스를 만듭니다. filters는 DomainFilter와 Filter 인스턴스의 리스트입니다. filters가 빈 리스트면, traces의 사본으로 새 Snapshot 인스턴스를 반환합니다.

모든 포함 필터가 한 번에 적용되며, 아무런 포함 필터도 일치하지 않으면 트레이스는 무시됩니다. 하나 이상의 제외 필터가 일치하면 트레이스는 무시됩니다.

버전 3.6에서 변경: DomainFilter 인스턴스도 이제 filters에서 허용됩니다.

classmethod load(filename)

파일에서 스냅샷을 로드합니다.

dump()도 참조하십시오.

statistics(key_type: str, cumulative: bool = False)

key_type 별로 그룹화된 Statistic 인스턴스의 정렬된 리스트로 통계를 가져옵니다:

key_type

설명

'filename'

파일명

'lineno'

파일명과 줄 번호

'traceback'

트레이스백

cumulative가 True이면, 가장 최근의 프레임뿐만 아니라, 트레이스의 트레이스백의 모든 프레임에 대한 메모리 블록의 크기와 개수를 누적합니다. 누적 모드는 key_type이 'filename'과 'lineno'와 같을 때만 사용할 수 있습니다.

결과는 다음 값에 따라 내림차순으로 정렬됩니다: Statistic.size, Statistic.count 그런 다음 Statistic.traceback.

traceback_limit

traces의 트레이스백에 저장된 최대 프레임 수: 스냅샷을 취할 때 get_traceback_limit()의 결과.

traces

파이썬이 할당한 모든 메모리 블록의 트레이스: Trace 인스턴스의 시퀀스.

시퀀스의 순서는 정의되지 않았습니다. 정렬된 통계 리스트를 얻으려면 Snapshot.statistics() 메서드를 사용하십시오.

Statistic

class tracemalloc.Statistic

메모리 할당 통계.

Snapshot.statistics()는 Statistic 인스턴스의 리스트를 반환합니다.

StatisticDiff 클래스도 참조하십시오.

count

메모리 블록 수 (int).

size

총 메모리 블록의 바이트 단위 크기 (int).

traceback

메모리 블록이 할당된 곳의 트레이스백, Traceback 인스턴스.

StatisticDiff

class tracemalloc.StatisticDiff

기존 Snapshot 인스턴스와 새 인스턴스 간의 메모리 할당에 대한 통계적 차이.

Snapshot.compare_to()는 StatisticDiff 인스턴스의 리스트를 반환합니다. Statistic 클래스도 참조하십시오.

count

새 스냅샷의 메모리 블록 수 (int): 새 스냅샷에서 메모리 블록이 해제되었으면 0.

count_diff

이전 스냅샷과 새 스냅샷 간의 메모리 블록 수의 차이 (int): 메모리 블록이 새 스냅샷에 할당되었으면 0.

size

새 스냅샷에서 총 메모리 블록의 바이트 단위 크기 (int): 새 스냅샷에서 메모리 블록이 해제되었으면 0.

size_diff

이전 스냅샷과 새 스냅샷 사이의 총 메모리 블록 크기의 바이트 단위 차이 (int): 메모리 블록이 새 스냅샷에 할당되었으면 0.

traceback

메모리 블록이 할당된 곳의 트레이스백, Traceback 인스턴스.

Trace

class tracemalloc.Trace

메모리 블록의 트레이스.

Snapshot.traces 어트리뷰트는 Trace 인스턴스의 시퀀스입니다.

버전 3.6에서 변경: domain 어트리뷰트를 추가했습니다.

domain

메모리 블록의 주소 공간 (int). 읽기 전용 프로퍼티.

tracemalloc은 도메인 0을 사용하여 파이썬의 메모리 할당을 추적합니다. C 확장은 다른 도메인을 사용하여 다른 리소스를 추적 할 수 있습니다.

size

메모리 블록의 바이트 단위 크기 (int).

traceback

메모리 블록이 할당된 곳의 트레이스백, Traceback 인스턴스.

Traceback

class tracemalloc.Traceback

가장 오래된 프레임에서 가장 최근 프레임 순으로 정렬된 Frame 인스턴스의 시퀀스.

트레이스백은 적어도 1프레임을 포함합니다. tracemalloc 모듈이 프레임을 가져오지 못하면, 줄 번호 0의 파일명 "<unknown>"이 사용됩니다.

스냅샷을 취할 때, 트레이스의 트레이스백은 get_traceback_limit() 프레임으로 제한됩니다. take_snapshot() 함수를 참조하십시오. 트레이스백의 원래 프레임 수는 Traceback.total_nframe 어트리뷰트에 저장됩니다. 이를 통해 트레이스백 제한으로 인해 트레이스백이 잘렸는지 알 수 있습니다.

Trace.traceback 어트리뷰트는 Traceback 인스턴스의 인스턴스입니다.

버전 3.7에서 변경: 프레임은 이제 가장 최근에서 가장 오래된 것 대신, 가장 오래된 것에서 가장 최근으로 정렬됩니다.

total_nframe

자르기 전에 트레이스백을 구성한 총 프레임 수. 정보가 없으면 이 어트리뷰트를 None으로 설정할 수 있습니다.

버전 3.9에서 변경: Traceback.total_nframe 어트리뷰트가 추가되었습니다.

format(limit=None, most_recent_first=False)

Format the traceback as a list of lines. Use the linecache module to retrieve lines from the source code. If limit is set, format the limit most recent frames if limit is positive. Otherwise, format the abs(limit) oldest frames. If most_recent_first is True, the order of the formatted frames is reversed, returning the most recent frame first instead of last.

format()에 줄 넘김 문자가 포함되지 않는다는 점을 제외하고, traceback.format_tb() 함수와 유사합니다.

예:

print("Traceback (most recent call first):")
for line in traceback:
    print(line)

출력:

Traceback (most recent call first):
  File "test.py", line 9
    obj = Object()
  File "test.py", line 12
    tb = tracemalloc.get_object_traceback(f())

소프트웨어 패키징 및 배포

이 라이브러리는 파이썬 소프트웨어를 게시하고 설치하는 데 도움을 줍니다. 이 모듈은 파이썬 패키지 색인 [https://pypi.org]과 함께 작동하도록 설계되었지만, 로컬 색인 서버와 함께 사용할 수도, 색인 서버 없이 사용할 수도 있습니다.

ensurepip — Bootstrapping the pip installer

명령 줄 인터페이스

모듈 API

version()

bootstrap()

venv — Creation of virtual environments

가상 환경 만들기

How venvs work

API

EnvBuilder

create()

ensure_directories()

create_configuration()

setup_python()

setup_scripts()

upgrade_dependencies()

post_setup()

install_scripts()

create_git_ignore_file()

create()

EnvBuilder 확장 예제

zipapp — Manage executable Python zip archives

기본 예

명령 줄 인터페이스

파이썬 API

create_archive()

get_interpreter()

예

인터프리터 지정하기

zipapp으로 독립형 응용 프로그램 만들기

경고

파이썬 Zip 응용 프로그램 아카이브 형식

ensurepip — Bootstrapping the pip installer

Added in version 3.4.

Source code: Lib/ensurepip [https://github.com/python/cpython/tree/main/Lib/ensurepip]

ensurepip 패키지는 pip 설치 프로그램을 기존의 파이썬 설치나 가상 환경으로 부트스트랩 하는데 필요한 지원을 제공합니다. 이 부트스트랩 접근 방식은 pip가 자체 배포 주기가 있는 독립적인 프로젝트이며, 최신 사용 가능한 안정 버전이 CPython 참조 인터프리터의 유지 보수와 기능 배포에 번들로 제공된다는 사실을 반영합니다.

대부분, 파이썬의 최종 사용자는 이 모듈을 직접 호출할 필요가 없습니다 (pip는 기본적으로 부트스트랩 되어있어야 하기 때문입니다). 하지만, 파이썬을 설치할 때 (또는 가상 환경을 만들 때) pip를 건너뛰었거나 그 후에 명시적으로 pip를 제거했다면 필요할 수 있습니다.

참고

이 모듈은 인터넷에 접속하지 않습니다. pip를 부트스트랩 하는 데 필요한 모든 구성 요소는 패키지의 내부 부품으로 포함됩니다.

더 보기

파이썬 모듈 설치하기

파이썬 패키지를 설치하기 위한 최종 사용자 지침서

PEP 453 [https://peps.python.org/pep-0453/]: 파이썬 설치에서 pip의 명시적 부트스트랩

이 모듈의 원래 근거와 사양.

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

명령 줄 인터페이스

명령 줄 인터페이스는 인터프리터의 -m 스위치를 사용하여 호출됩니다.

가장 간단한 호출은 이렇습니다:

python -m ensurepip

This invocation will install pip if it is not already installed, but otherwise does nothing. To ensure the installed version of pip is at least as recent as the one available in ensurepip, pass the --upgrade option:

python -m ensurepip --upgrade

기본적으로, pip는 현재 가상 환경(활성화되었다면)이나 시스템 사이트 패키지(활성 가상 환경이 없으면)에 설치됩니다. 설치 위치는 두 개의 추가 명령 줄 옵션을 통해 제어할 수 있습니다:

--root dir: Installs pip relative to the given root directory rather than the root of the currently active virtual environment (if any) or the default root for the current Python installation.

--user: pip를 현재 파이썬 설치에 전역적으로 설치하지 않고 사용자 사이트 패키지 디렉터리에 설치합니다 (이 옵션은 활성 가상 환경에서는 허용되지 않습니다).

기본적으로, pipX 와 pipX.Y 스크립트가 설치됩니다 (여기서 X.Y는 ensurepip를 호출하는 데 사용된 파이썬 버전을 나타냅니다). 설치된 스크립트는 두 개의 추가 명령 줄 옵션을 통해 제어할 수 있습니다:

--altinstall: 대안 설치가 요청되면, pipX 스크립트가 설치되지 않습니다.

--default-pip: “기본 pip” 설치가 요청되면, 두 개의 일반 스크립트에 더해 pip 스크립트가 설치됩니다.

두 스크립트 선택 옵션을 모두 제공하면 예외가 발생합니다.

모듈 API

ensurepip는 프로그래밍 방식으로 사용하기 위해 두 가지 함수를 제공합니다:

ensurepip.version()

Returns a string specifying the available version of pip that will be installed when bootstrapping an environment.

ensurepip.bootstrap(root=None, upgrade=False, user=False, altinstall=False, default_pip=False, verbosity=0)

pip를 현재나 지정된 환경으로 부트스트랩 합니다.

root는 상대 경로로 설치할 대안 루트 디렉터리를 지정합니다. root가 None이면, 설치는 현재 환경의 기본 설치 위치를 사용합니다.

upgrade indicates whether or not to upgrade an existing installation of an earlier version of pip to the available version.

user는 전역으로 설치하는 대신 사용자 구성을 사용할지를 나타냅니다.

기본적으로, pipX 및 pipX.Y 스크립트가 설치됩니다 (여기서 X.Y는 현재 버전의 파이썬을 나타냅니다).

altinstall가 설정되면, pipX가 설치되지 않습니다.

default_pip가 설정되면, 두 개의 일반 스크립트에 더해 pip가 설치됩니다.

altinstall 과 default_pip를 모두 설정하면 ValueError가 발생합니다.

verbosity는 부트스트랩 연산에서 sys.stdout로 출력하는 수준을 제어합니다.

인자 root로 감사 이벤트(auditing event) ensurepip.bootstrap을 발생시킵니다.

참고

부트스트랩 프로세스에는 sys.path 와 os.environ 모두에 부작용이 있습니다. 대신 자식 프로세스에서 명령 줄 인터페이스를 호출하면 이러한 부작용을 피할 수 있습니다.

참고

부트스트랩 프로세스는 pip에 필요한 추가 모듈을 설치할 수 있지만, 다른 소프트웨어는 이러한 종속성이 기본적으로 항상 존재한다고 가정해서는 안 됩니다 (pip의 차후 버전에서 제거될 수 있기 때문입니다).

venv — Creation of virtual environments

Added in version 3.3.

소스 코드: Lib/venv/ [https://github.com/python/cpython/tree/main/Lib/venv/]

The venv module supports creating lightweight “virtual environments”, each with their own independent set of Python packages installed in their site directories. A virtual environment is created on top of an existing Python installation, known as the virtual environment’s “base” Python, and may optionally be isolated from the packages in the base environment, so only those explicitly installed in the virtual environment are available. See Virtual Environments and site’s virtual environments documentation for more information.

When used from within a virtual environment, common installation tools such as pip [https://pypi.org/project/pip/] will install Python packages into a virtual environment without needing to be told to do so explicitly.

A virtual environment is (amongst other things):

Used to contain a specific Python interpreter and software libraries and binaries which are needed to support a project (library or application). These are by default isolated from software in other virtual environments and Python interpreters and libraries installed in the operating system.

Contained in a directory, conventionally named .venv or venv in the project directory, or under a container directory for lots of virtual environments, such as ~/.virtualenvs.

Not checked into source control systems such as Git.

Considered as disposable – it should be simple to delete and recreate it from scratch. You don’t place any project code in the environment.

Not considered as movable or copyable – you just recreate the same environment in the target location.

See PEP 405 [https://peps.python.org/pep-0405/] for more background on Python virtual environments.

더 보기

Python Packaging User Guide: Creating and using virtual environments [https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/#create-and-use-virtual-environments]

Availability: not Android, not iOS, not WASI.

This module is not supported on mobile platforms or WebAssembly platforms.

가상 환경 만들기

Virtual environments are created by executing the venv module:

python -m venv /path/to/new/virtual/environment

This creates the target directory (including parent directories as needed) and places a pyvenv.cfg file in it with a home key pointing to the Python installation from which the command was run. It also creates a bin (or Scripts on Windows) subdirectory containing a copy or symlink of the Python executable (as appropriate for the platform or arguments used at environment creation time). It also creates a lib/pythonX.Y/site-packages subdirectory (on Windows, this is Libsite-packages). If an existing directory is specified, it will be re-used.

버전 3.5에서 변경: 이제 가상 환경을 만들 때 venv를 사용하는 것이 좋습니다.

Deprecated since version 3.6, removed in version 3.8: pyvenv was the recommended tool for creating virtual environments for Python 3.3 and 3.4, and replaced in 3.5 by executing venv directly.

On Windows, invoke the venv command as follows:

PS> python -m venv C:\path\to\new\virtual\environment

명령에 -h를 사용하면 사용 가능한 옵션이 표시됩니다:

usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear]
            [--upgrade] [--without-pip] [--prompt PROMPT] [--upgrade-deps]
            [--without-scm-ignore-files]
            ENV_DIR [ENV_DIR ...]

Creates virtual Python environments in one or more target directories.

positional arguments:
  ENV_DIR               A directory to create the environment in.

options:
  -h, --help            show this help message and exit
  --system-site-packages
                        Give the virtual environment access to the system
                        site-packages dir.
  --symlinks            Try to use symlinks rather than copies, when
                        symlinks are not the default for the platform.
  --copies              Try to use copies rather than symlinks, even when
                        symlinks are the default for the platform.
  --clear               Delete the contents of the environment directory
                        if it already exists, before environment creation.
  --upgrade             Upgrade the environment directory to use this
                        version of Python, assuming Python has been
                        upgraded in-place.
  --without-pip         Skips installing or upgrading pip in the virtual
                        environment (pip is bootstrapped by default)
  --prompt PROMPT       Provides an alternative prompt prefix for this
                        environment.
  --upgrade-deps        Upgrade core dependencies (pip) to the latest
                        version in PyPI
  --without-scm-ignore-files
                        Skips adding SCM ignore files to the environment
                        directory (Git is supported by default).

Once an environment has been created, you may wish to activate it, e.g. by
sourcing an activate script in its bin directory.

버전 3.4에서 변경: Installs pip by default, added the --without-pip and --copies options.

버전 3.4에서 변경: 이전 버전에서는, --clear 나 --upgrade 옵션이 제공되지 않았을 때, 대상 디렉터리가 이미 존재하면 에러가 발생했습니다.

버전 3.9에서 변경: Add --upgrade-deps option to upgrade pip + setuptools to the latest on PyPI.

버전 3.12에서 변경: setuptools is no longer a core venv dependency.

버전 3.13에서 변경: Added the --without-scm-ignore-files option.

버전 3.13에서 변경: venv now creates a .gitignore file for Git by default.

참고

심볼릭 링크가 윈도우에서 지원되지만, 추천하지는 않습니다. 특히 파일 탐색기에서 python.exe를 더블 클릭하면 심볼릭 링크를 열심히 따라가고(resolve) 가상 환경은 무시됩니다.

참고

마이크로소프트 윈도우에서는 사용자에 대한 실행 정책을 설정하여 Activate.ps1 스크립트를 활성화해야 할 수도 있습니다. 다음 PowerShell 명령을 실행하여 이를 수행할 수 있습니다:

PS C:\> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

자세한 정보는 About Execution Policies [https://go.microsoft.com/fwlink/?LinkID=135170]를 참조하십시오.

The created pyvenv.cfg file also includes the include-system-site-packages key, set to true if venv is run with the --system-site-packages option, false otherwise.

--without-pip 옵션을 주지 않는 한, 가상 환경으로 pip을 부트스트랩 하기 위해 ensurepip가 호출됩니다.

venv에 여러 경로를 지정할 수 있습니다. 이때 지정된 옵션에 따라 제공된 각 경로에서 같은 가상 환경이 만들어집니다.

How venvs work

When a Python interpreter is running from a virtual environment, sys.prefix and sys.exec_prefix point to the directories of the virtual environment, whereas sys.base_prefix and sys.base_exec_prefix point to those of the base Python used to create the environment. It is sufficient to check sys.prefix != sys.base_prefix to determine if the current interpreter is running from a virtual environment.

A virtual environment may be “activated” using a script in its binary directory (bin on POSIX; Scripts on Windows). This will prepend that directory to your PATH, so that running python will invoke the environment’s Python interpreter and you can run installed scripts without having to use their full path. The invocation of the activation script is platform-specific (<venv> must be replaced by the path to the directory containing the virtual environment):

플랫폼

셸

가상 환경을 활성화하는 명령

POSIX

bash/zsh

$ source <venv>/bin/activate

fish

$ source <venv>/bin/activate.fish

csh/tcsh

$ source <venv>/bin/activate.csh

pwsh

$ <venv>/bin/Activate.ps1

윈도우

cmd.exe

C:\> <venv>\Scripts\activate.bat

PowerShell

PS C:\> <venv>\Scripts\Activate.ps1

Added in version 3.4: fish and csh activation scripts.

Added in version 3.8: PowerShell Core 지원을 위해 POSIX에 설치된 PowerShell 활성화 스크립트.

You don’t specifically need to activate a virtual environment, as you can just specify the full path to that environment’s Python interpreter when invoking Python. Furthermore, all scripts installed in the environment should be runnable without activating it.

In order to achieve this, scripts installed into virtual environments have a “shebang” line which points to the environment’s Python interpreter, #!/<path-to-venv>/bin/python. This means that the script will run with that interpreter regardless of the value of PATH. On Windows, “shebang” line processing is supported if you have the 윈도우 용 파이썬 런처 installed. Thus, double-clicking an installed script in a Windows Explorer window should run it with the correct interpreter without the environment needing to be activated or on the PATH.

When a virtual environment has been activated, the VIRTUAL_ENV environment variable is set to the path of the environment. Since explicitly activating a virtual environment is not required to use it, VIRTUAL_ENV cannot be relied upon to determine whether a virtual environment is being used.

경고

Because scripts installed in environments should not expect the environment to be activated, their shebang lines contain the absolute paths to their environment’s interpreters. Because of this, environments are inherently non-portable, in the general case. You should always have a simple means of recreating an environment (for example, if you have a requirements file requirements.txt, you can invoke pip install -r requirements.txt using the environment’s pip to install all of the packages needed by the environment). If for any reason you need to move the environment to a new location, you should recreate it at the desired location and delete the one at the old location. If you move an environment because you moved a parent directory of it, you should recreate the environment in its new location. Otherwise, software installed into the environment may not work as expected.

You can deactivate a virtual environment by typing deactivate in your shell. The exact mechanism is platform-specific and is an internal implementation detail (typically, a script or shell function will be used).

API

위에서 설명한 고수준 메서드는 제삼자 가상 환경 작성자가 필요에 따라 환경을 사용자 정의할 수 있는 메커니즘을 제공하는 간단한 API를 사용합니다: EnvBuilder 클래스.

class venv.EnvBuilder(system_site_packages=False, clear=False, symlinks=False, upgrade=False, with_pip=False, prompt=None, upgrade_deps=False, *, scm_ignore_files=frozenset())

EnvBuilder 클래스는 인스턴스를 만들 때 다음 키워드 인자를 받아들입니다:

system_site_packages – a boolean value indicating that the system Python site-packages should be available to the environment (defaults to False).

clear – a boolean value which, if true, will delete the contents of any existing target directory, before creating the environment.

symlinks – a boolean value indicating whether to attempt to symlink the Python binary rather than copying.

upgrade – a boolean value which, if true, will upgrade an existing environment with the running Python - for use when that Python has been upgraded in-place (defaults to False).

with_pip – a boolean value which, if true, ensures pip is installed in the virtual environment. This uses ensurepip with the --default-pip option.

prompt – a string to be used after virtual environment is activated (defaults to None which means directory name of the environment would be used). If the special string "." is provided, the basename of the current directory is used as the prompt.

upgrade_deps – Update the base venv modules to the latest on PyPI

scm_ignore_files – Create ignore files based for the specified source control managers (SCM) in the iterable. Support is defined by having a method named create_{scm}_ignore_file. The only value supported by default is "git" via create_git_ignore_file().

버전 3.4에서 변경: with_pip 매개 변수 추가

버전 3.6에서 변경: prompt 매개 변수 추가

버전 3.9에서 변경: upgrade_deps 매개 변수 추가

버전 3.13에서 변경: Added the scm_ignore_files parameter

EnvBuilder may be used as a base class.

create(env_dir)

가상 환경을 담을 대상 디렉터리(절대 또는 현재 디렉터리에 대한 상대)를 지정해서 가상 환경을 만듭니다. create 메서드는 지정된 디렉터리에 환경을 만들거나 적절한 예외를 발생시킵니다.

EnvBuilder 클래스의 create 메서드는 서브 클래스가 사용자 정의할 수 있는 훅을 보여줍니다:

def create(self, env_dir):
    """
    Create a virtualized Python environment in a directory.
    env_dir is the target directory to create an environment in.
    """
    env_dir = os.path.abspath(env_dir)
    context = self.ensure_directories(env_dir)
    self.create_configuration(context)
    self.setup_python(context)
    self.setup_scripts(context)
    self.post_setup(context)

메서드 ensure_directories(), create_configuration(), setup_python(), setup_scripts() 및 post_setup() 각각을 재정의할 수 있습니다.

ensure_directories(env_dir)

Creates the environment directory and all necessary subdirectories that don’t already exist, and returns a context object. This context object is just a holder for attributes (such as paths) for use by the other methods. If the EnvBuilder is created with the arg clear=True, contents of the environment directory will be cleared and then all necessary subdirectories will be recreated.

The returned context object is a types.SimpleNamespace with the following attributes:

env_dir - The location of the virtual environment. Used for __VENV_DIR__ in activation scripts (see install_scripts()).

env_name - The name of the virtual environment. Used for __VENV_NAME__ in activation scripts (see install_scripts()).

prompt - The prompt to be used by the activation scripts. Used for __VENV_PROMPT__ in activation scripts (see install_scripts()).

executable - The underlying Python executable used by the virtual environment. This takes into account the case where a virtual environment is created from another virtual environment.

inc_path - The include path for the virtual environment.

lib_path - The purelib path for the virtual environment.

bin_path - The script path for the virtual environment.

bin_name - The name of the script path relative to the virtual environment location. Used for __VENV_BIN_NAME__ in activation scripts (see install_scripts()).

env_exe - The name of the Python interpreter in the virtual environment. Used for __VENV_PYTHON__ in activation scripts (see install_scripts()).

env_exec_cmd - The name of the Python interpreter, taking into account filesystem redirections. This can be used to run Python in the virtual environment.

버전 3.11에서 변경: The venv sysconfig installation scheme is used to construct the paths of the created directories.

버전 3.12에서 변경: The attribute lib_path was added to the context, and the context object was documented.

create_configuration(context)

환경에 pyvenv.cfg 구성 파일을 만듭니다.

setup_python(context)

환경에 파이썬 실행 파일의 복사본이나 심볼릭 링크를 만듭니다. POSIX 시스템에서, 특정 실행 파일 python3.x가 사용되면, 해당 이름의 파일이 이미 존재하지 않는 한 python 과 python3 심볼릭 링크가 해당 실행 파일을 가리키도록 만들어집니다.

setup_scripts(context)

플랫폼에 적합한 활성화 스크립트를 가상 환경에 설치합니다.

upgrade_dependencies(context)

Upgrades the core venv dependency packages (currently pip [https://pypi.org/project/pip/]) in the environment. This is done by shelling out to the pip executable in the environment.

Added in version 3.9.

버전 3.12에서 변경: setuptools [https://pypi.org/project/setuptools/] is no longer a core venv dependency.

post_setup(context)

제삼자 구현에서 재정의하여 가상 환경에 패키지를 사전 설치하거나 다른 생성 후 단계를 수행할 수 있는 메서드입니다.

install_scripts(context, path)

This method can be called from setup_scripts() or post_setup() in subclasses to assist in installing custom scripts into the virtual environment.

path is the path to a directory that should contain subdirectories common, posix, nt; each containing scripts destined for the bin directory in the environment. The contents of common and the directory corresponding to os.name are copied after some text replacement of placeholders:

__VENV_DIR__은 환경 디렉터리의 절대 경로로 치환됩니다.

__VENV_NAME__은 환경 이름(환경 디렉터리의 최종 경로 세그먼트)으로 치환됩니다.

__VENV_PROMPT__는 프롬프트(괄호로 묶인 환경 이름과 그 뒤의 스페이스)로 치환됩니다

__VENV_BIN_NAME__은 bin 디렉터리의 이름(bin 이나 Scripts)으로 치환됩니다.

__VENV_PYTHON__은 환경의 실행 파일의 절대 경로로 치환됩니다.

디렉터리는 존재하는 것이 허용됩니다 (기존 환경이 업그레이드될 때).

create_git_ignore_file(context)

Creates a .gitignore file within the virtual environment that causes the entire directory to be ignored by the Git source control manager.

Added in version 3.13.

버전 3.7.2에서 변경: 윈도우는 이제 실제 바이너리를 복사하는 대신 python[w].exe를 위한 리디렉터 스크립트를 사용합니다. 3.7.2 에서만, 소스 트리의 빌드에서 실행하지 않는 한 setup_python()아무 작업도 수행하지 않습니다.

버전 3.7.3에서 변경: 윈도우는 setup_scripts() 대신 setup_python()의 일부로 리디렉터 스크립트를 복사합니다. 이것은 3.7.2는 해당하지 않습니다. 심볼릭 링크를 사용하면, 원래 실행 파일이 링크됩니다.

모듈 수준의 편리 함수도 있습니다:

venv.create(env_dir, system_site_packages=False, clear=False, symlinks=False, with_pip=False, prompt=None, upgrade_deps=False, *, scm_ignore_files=frozenset())

주어진 키워드 인자로 EnvBuilder를 만들고, env_dir 인자로 create() 메서드를 호출합니다.

Added in version 3.3.

버전 3.4에서 변경: Added the with_pip parameter

버전 3.6에서 변경: Added the prompt parameter

버전 3.9에서 변경: Added the upgrade_deps parameter

버전 3.13에서 변경: Added the scm_ignore_files parameter

EnvBuilder 확장 예제

다음 스크립트는 생성된 가상 환경에 setuptools 와 pip을 설치하는 서브 클래스를 구현하여 EnvBuilder를 확장하는 방법을 보여줍니다:

import os
import os.path
from subprocess import Popen, PIPE
import sys
from threading import Thread
from urllib.parse import urlparse
from urllib.request import urlretrieve
import venv

class ExtendedEnvBuilder(venv.EnvBuilder):
    """
    This builder installs setuptools and pip so that you can pip or
    easy_install other packages into the created virtual environment.

    :param nodist: If true, setuptools and pip are not installed into the
                   created virtual environment.
    :param nopip: If true, pip is not installed into the created
                  virtual environment.
    :param progress: If setuptools or pip are installed, the progress of the
                     installation can be monitored by passing a progress
                     callable. If specified, it is called with two
                     arguments: a string indicating some progress, and a
                     context indicating where the string is coming from.
                     The context argument can have one of three values:
                     'main', indicating that it is called from virtualize()
                     itself, and 'stdout' and 'stderr', which are obtained
                     by reading lines from the output streams of a subprocess
                     which is used to install the app.

                     If a callable is not specified, default progress
                     information is output to sys.stderr.
    """

    def __init__(self, *args, **kwargs):
        self.nodist = kwargs.pop('nodist', False)
        self.nopip = kwargs.pop('nopip', False)
        self.progress = kwargs.pop('progress', None)
        self.verbose = kwargs.pop('verbose', False)
        super().__init__(*args, **kwargs)

    def post_setup(self, context):
        """
        Set up any packages which need to be pre-installed into the
        virtual environment being created.

        :param context: The information for the virtual environment
                        creation request being processed.
        """
        os.environ['VIRTUAL_ENV'] = context.env_dir
        if not self.nodist:
            self.install_setuptools(context)
        # Can't install pip without setuptools
        if not self.nopip and not self.nodist:
            self.install_pip(context)

    def reader(self, stream, context):
        """
        Read lines from a subprocess' output stream and either pass to a progress
        callable (if specified) or write progress information to sys.stderr.
        """
        progress = self.progress
        while True:
            s = stream.readline()
            if not s:
                break
            if progress is not None:
                progress(s, context)
            else:
                if not self.verbose:
                    sys.stderr.write('.')
                else:
                    sys.stderr.write(s.decode('utf-8'))
                sys.stderr.flush()
        stream.close()

    def install_script(self, context, name, url):
        _, _, path, _, _, _ = urlparse(url)
        fn = os.path.split(path)[-1]
        binpath = context.bin_path
        distpath = os.path.join(binpath, fn)
        # Download script into the virtual environment's binaries folder
        urlretrieve(url, distpath)
        progress = self.progress
        if self.verbose:
            term = '\n'
        else:
            term = ''
        if progress is not None:
            progress('Installing %s ...%s' % (name, term), 'main')
        else:
            sys.stderr.write('Installing %s ...%s' % (name, term))
            sys.stderr.flush()
        # Install in the virtual environment
        args = [context.env_exe, fn]
        p = Popen(args, stdout=PIPE, stderr=PIPE, cwd=binpath)
        t1 = Thread(target=self.reader, args=(p.stdout, 'stdout'))
        t1.start()
        t2 = Thread(target=self.reader, args=(p.stderr, 'stderr'))
        t2.start()
        p.wait()
        t1.join()
        t2.join()
        if progress is not None:
            progress('done.', 'main')
        else:
            sys.stderr.write('done.\n')
        # Clean up - no longer needed
        os.unlink(distpath)

    def install_setuptools(self, context):
        """
        Install setuptools in the virtual environment.

        :param context: The information for the virtual environment
                        creation request being processed.
        """
        url = "https://bootstrap.pypa.io/ez_setup.py"
        self.install_script(context, 'setuptools', url)
        # clear up the setuptools archive which gets downloaded
        pred = lambda o: o.startswith('setuptools-') and o.endswith('.tar.gz')
        files = filter(pred, os.listdir(context.bin_path))
        for f in files:
            f = os.path.join(context.bin_path, f)
            os.unlink(f)

    def install_pip(self, context):
        """
        Install pip in the virtual environment.

        :param context: The information for the virtual environment
                        creation request being processed.
        """
        url = 'https://bootstrap.pypa.io/get-pip.py'
        self.install_script(context, 'pip', url)

def main(args=None):
    import argparse

    parser = argparse.ArgumentParser(prog=__name__,
                                     description='Creates virtual Python '
                                                 'environments in one or '
                                                 'more target '
                                                 'directories.')
    parser.add_argument('dirs', metavar='ENV_DIR', nargs='+',
                        help='A directory in which to create the '
                             'virtual environment.')
    parser.add_argument('--no-setuptools', default=False,
                        action='store_true', dest='nodist',
                        help="Don't install setuptools or pip in the "
                             "virtual environment.")
    parser.add_argument('--no-pip', default=False,
                        action='store_true', dest='nopip',
                        help="Don't install pip in the virtual "
                             "environment.")
    parser.add_argument('--system-site-packages', default=False,
                        action='store_true', dest='system_site',
                        help='Give the virtual environment access to the '
                             'system site-packages dir.')
    if os.name == 'nt':
        use_symlinks = False
    else:
        use_symlinks = True
    parser.add_argument('--symlinks', default=use_symlinks,
                        action='store_true', dest='symlinks',
                        help='Try to use symlinks rather than copies, '
                             'when symlinks are not the default for '
                             'the platform.')
    parser.add_argument('--clear', default=False, action='store_true',
                        dest='clear', help='Delete the contents of the '
                                           'virtual environment '
                                           'directory if it already '
                                           'exists, before virtual '
                                           'environment creation.')
    parser.add_argument('--upgrade', default=False, action='store_true',
                        dest='upgrade', help='Upgrade the virtual '
                                             'environment directory to '
                                             'use this version of '
                                             'Python, assuming Python '
                                             'has been upgraded '
                                             'in-place.')
    parser.add_argument('--verbose', default=False, action='store_true',
                        dest='verbose', help='Display the output '
                                             'from the scripts which '
                                             'install setuptools and pip.')
    options = parser.parse_args(args)
    if options.upgrade and options.clear:
        raise ValueError('you cannot supply --upgrade and --clear together.')
    builder = ExtendedEnvBuilder(system_site_packages=options.system_site,
                                   clear=options.clear,
                                   symlinks=options.symlinks,
                                   upgrade=options.upgrade,
                                   nodist=options.nodist,
                                   nopip=options.nopip,
                                   verbose=options.verbose)
    for d in options.dirs:
        builder.create(d)

if __name__ == '__main__':
    rc = 1
    try:
        main()
        rc = 0
    except Exception as e:
        print('Error: %s' % e, file=sys.stderr)
    sys.exit(rc)

이 스크립트는 온라인 [https://gist.github.com/vsajip/4673395]에서 내려받을 수도 있습니다.

zipapp — Manage executable Python zip archives

Added in version 3.5.

소스 코드: Lib/zipapp.py [https://github.com/python/cpython/tree/main/Lib/zipapp.py]

이 모듈은 파이썬 인터프리터가 직접 실행할 수 있는 파이썬 코드를 포함하는 zip 파일 생성을 관리하는 도구를 제공합니다. 이 모듈은 명령 줄 인터페이스와 파이썬 API를 모두 제공합니다.

기본 예

다음 예제는 명령 줄 인터페이스를 사용하여 파이썬 코드가 포함된 디렉터리에서 실행 가능 아카이브를 만드는 방법을 보여줍니다. 실행하면, 아카이브가 아카이브의 모듈 myapp에서 main 함수를 실행합니다.

$ python -m zipapp myapp -m "myapp:main"
$ python myapp.pyz
<output from myapp>

명령 줄 인터페이스

명령 줄에서 프로그램으로 호출될 때, 다음 형식이 사용됩니다:

$ python -m zipapp source [options]

source가 디렉터리면, source의 내용으로부터 아카이브를 만듭니다. source가 파일이면, 아카이브여야 하며, 대상 아카이브로 복사됩니다 (또는 –info 옵션이 지정되면 셔뱅(shebang) 줄의 내용이 표시됩니다).

다음과 같은 옵션이 이해됩니다:

-o <output>, --output=<output>

출력을 output이라는 이름의 파일에 씁니다. 이 옵션을 지정하지 않으면, 출력 파일명은 입력 source와 같고, 확장자 .pyz가 추가됩니다. 명시적인 파일명이 제공되면, 그대로 사용됩니다 (그래서 필요하면 .pyz 확장자를 포함해야 합니다).

source가 아카이브이면 반드시 출력 파일명을 지정해야 합니다 (그리고 이 경우, output은 source와 달라야 합니다).

-p <interpreter>, --python=<interpreter>

실행할 명령으로 interpreter를 지정하여 #! 줄을 아카이브에 추가합니다. 또한, POSIX에서, 아카이브를 실행 파일로 만듭니다. 기본값은 #! 줄을 쓰지 않고, 파일을 실행 파일로 만들지 않는 것입니다.

-m <mainfn>, --main=<mainfn>

아카이브에 mainfn을 실행하는 __main__.py 파일을 씁니다. mainfn 인자는 “pkg.mod:fn” 형식이어야 합니다. 여기서 “pkg.mod”는 아카이브의 패키지/모듈이며, “fn”은 주어진 모듈에 있는 콜러블입니다. __main__.py 파일은 그 콜러블을 실행합니다.

아카이브를 복사할 때 --main을 지정할 수 없습니다.

-c, --compress

디플레이트(deflate) 메서드로 파일을 압축하여, 출력 파일의 크기를 줄입니다. 기본적으로, 파일은 아카이브에 압축되지 않은 상태로 저장됩니다.

아카이브를 복사할 때 --compress는 효과가 없습니다.

Added in version 3.7.

--info

진단 목적으로, 아카이브에 내장된 인터프리터를 표시합니다. 이 경우, 다른 옵션은 무시되고 SOURCE는 디렉터리가 아닌 아카이브여야 합니다.

-h, --help

간단한 사용법 메시지를 인쇄하고 종료합니다.

파이썬 API

이 모듈은 두 개의 편의 함수를 정의합니다:

zipapp.create_archive(source, target=None, interpreter=None, main=None, filter=None, compressed=False)

source로 응용 프로그램 아카이브를 만듭니다. 소스는 다음 중 하나일 수 있습니다:

디렉터리 이름, 또는 디렉터리를 참조하는 경로류 객체. 이 경우 해당 디렉터리의 내용으로 새 응용 프로그램 아카이브가 만들어집니다.

기존 응용 프로그램 아카이브 파일의 이름, 또는 이러한 파일을 참조하는 경로류 객체. 이 경우 파일이 대상(target)으로 복사됩니다 (interpreter 인자에 제공된 값을 반영하도록 수정하면서). 필요하면, 파일 이름에 .pyz 확장자가 포함되어야 합니다.

바이너리 모드에서 읽기로 열린 파일 객체. 파일의 내용은 응용 프로그램 아카이브여야 하며, 파일 객체는 아카이브의 시작 부분에 위치한 것으로 가정합니다.

target 인자는 결과 아카이브가 기록될 위치를 결정합니다:

파일 이름이거나 경로류 객체이면, 아카이브가 그 파일에 기록됩니다.

열린 파일 객체면, 그 파일 객체에 아카이브가 기록되며, 파일은 바이너리 모드로 쓰기로 열려 있어야 합니다.

target이 생략되면 (또는 None이면), 소스(source)는 디렉터리여야 하며 대상은 .pyz 확장자가 추가된 소스와 이름이 같은 파일이 됩니다.

interpreter 인자는 아카이브가 실행될 파이썬 인터프리터의 이름을 지정합니다. 아카이브 시작 부분에 “셔뱅(shebang)” 줄로 기록됩니다. POSIX에서는 이를 OS가 해석하고, 윈도우에서는 파이썬 런처가 이를 처리합니다. interpreter를 생략하면 셔뱅 줄이 기록되지 않습니다. interpreter가 지정되고 target이 파일명이면, target 파일의 실행 가능 비트가 설정됩니다.

main 인자는 아카이브의 메인 프로그램으로 사용될 콜러블의 이름을 지정합니다. 소스가 디렉터리이고 소스에 아직 __main__.py 파일이 없을 때만 지정할 수 있습니다. main 인자는 “pkg.module:callable” 형식이어야 하며 아카이브는 “pkg.module”을 임포트 하고 인자 없이 지정된 콜러블을 실행해서 실행됩니다. 소스가 디렉터리이고 __main__.py 파일을 포함하지 않을 때 main을 생략하는 것은 에러입니다, 그렇지 않으면 결과 아카이브가 실행 가능하지 않기 때문입니다.

선택적 filter 인자는 추가되는 파일의 (소스 디렉터리에 상대적인) 경로를 나타내는 Path 객체가 전달되는 콜백 함수를 지정합니다. 파일을 추가하려면 True를 반환해야 합니다.

선택적 compressed 인자는 파일을 압축할지를 결정합니다. True로 설정하면, 아카이브의 파일이 디플레이트(deflate) 메서드로 압축됩니다; 그렇지 않으면 파일이 압축되지 않은 상태로 저장됩니다. 기존 아카이브를 복사할 때는 이 인자가 효과가 없습니다.

source나 target에 파일 객체가 지정되면, create_archive를 호출한 후 파일 객체를 닫는 것은 호출자의 책임입니다.

기존 아카이브를 복사할 때, 제공된 파일 객체에는 read와 readline 또는 write 메서드만 필요합니다. 디렉터리에서 아카이브를 만들 때, 대상이 파일 객체면 zipfile.ZipFile 클래스로 전달되며, 해당 클래스에 필요한 메서드를 제공해야 합니다.

버전 3.7에서 변경: Added the filter and compressed parameters.

zipapp.get_interpreter(archive)

아카이브 시작 부분에서 #! 줄에 지정된 인터프리터를 반환합니다. #! 줄이 없으면, None을 반환합니다. archive 인자는 파일명이나 바이너리 모드로 읽기로 열린 파일류 객체일 수 있습니다. 아카이브가 시작 부분에 위치한 것으로 가정합니다.

예

디렉터리를 아카이브로 패킹하고, 실행합니다.

$ python -m zipapp myapp
$ python myapp.pyz
<output from myapp>

create_archive() 함수를 사용하여 같은 작업을 수행할 수 있습니다:

>>> import zipapp
>>> zipapp.create_archive('myapp', 'myapp.pyz')

POSIX에서 응용 프로그램을 직접 실행할 수 있게 만들려면, 사용할 인터프리터를 지정하십시오.

$ python -m zipapp myapp -p "/usr/bin/env python"
$ ./myapp.pyz
<output from myapp>

기존 아카이브에서 셔뱅 줄을 바꾸려면, create_archive() 함수를 사용하여 수정된 아카이브를 만드십시오:

>>> import zipapp
>>> zipapp.create_archive('old_archive.pyz', 'new_archive.pyz', '/usr/bin/python3')

To update the file in place, do the replacement in memory using a BytesIO object, and then overwrite the source afterwards. Note that there is a risk when overwriting a file in place that an error will result in the loss of the original file. This code does not protect against such errors, but production code should do so. Also, this method will only work if the archive fits in memory:

>>> import zipapp
>>> import io
>>> temp = io.BytesIO()
>>> zipapp.create_archive('myapp.pyz', temp, '/usr/bin/python2')
>>> with open('myapp.pyz', 'wb') as f:
>>>     f.write(temp.getvalue())

인터프리터 지정하기

인터프리터를 지정한 다음 응용 프로그램 아카이브를 배포한다면, 사용된 인터프리터가 이식성 있는지 확인할 필요가 있음에 유의하십시오. 윈도우 용 파이썬 런처는 가장 일반적인 POSIX #! 줄 형식을 지원하지만, 고려해야 할 다른 문제가 있습니다:

“/usr/bin/env python”(또는 “/usr/bin/python”과 같은 “python” 명령의 다른 형식)을 사용한다면, 사용자에게 기본적으로 파이썬 2나 파이썬 3이 있을 수 있음을 고려해야 하고, 두 버전에서 작동하도록 코드를 작성하십시오.

“/usr/bin/env python3”과 같이 명시적인 버전을 사용하면 해당 버전이 없는 사용자에게는 응용 프로그램이 작동하지 않습니다. (여러분의 코드를 파이썬 2 호환으로 만들지 않았다면 이것이 여러분이 원하는 것일 수 있습니다).

“파이썬 X.Y 이상”이라고 말할 방법이 없어서, “/usr/bin/env python3.4”처럼 정확한 버전을 사용할 때는 주의하십시오. 예를 들어 파이썬 3.5 사용자를 위해서는 셔뱅 줄을 변경해야 합니다.

일반적으로, 여러분의 코드가 파이썬 2나 3중 어느 것으로 작성되었는지에 따라 “/usr/bin/env python2”나 “/usr/bin/env python3”을 사용해야 합니다.

zipapp으로 독립형 응용 프로그램 만들기

zipapp 모듈을 사용하면, 시스템에 적합한 버전의 파이썬만 설치되어있는 최종 사용자에게 배포 할 수 있는 필요한 모든 것이 담긴 파이썬 프로그램을 만들 수 있습니다. 이 작업의 핵심은 응용 프로그램 코드와 함께 모든 응용 프로그램의 종속성을 아카이브에 묶는 것입니다.

독립형 아카이브를 만드는 단계는 다음과 같습니다:

정상적으로 디렉터리에 응용 프로그램을 만드십시오, 그러면 __main__.py 파일과 모든 지원 응용 프로그램 코드를 포함하는 myapp 디렉터리를 얻게 됩니다.

pip을 사용하여 모든 응용 프로그램의 종속성을 myapp 디렉터리에 설치하십시오:

$ python -m pip install -r requirements.txt --target myapp

(이것은 requirements.txt 파일에 프로젝트 요구 사항이 있다고 가정합니다 - 그렇지 않으면, pip 명령 줄에 종속성을 수동으로 나열할 수 있습니다).

다음과 같이 응용 프로그램을 패키징하십시오:

$ python -m zipapp -p "interpreter" myapp

그러면 독립형 실행 파일이 생성되며, 사용 가능한 적절한 인터프리터가 있는 모든 시스템에서 실행할 수 있습니다. 자세한 내용은 인터프리터 지정하기를 참조하십시오. 단일 파일로 사용자에게 제공될 수 있습니다.

유닉스에서, myapp.pyz 파일은 그대로 실행 파일입니다. “평범한” 명령 이름을 선호하면, 파일 이름을 변경하여 .pyz 확장자를 제거할 수 있습니다. 윈도우에서, 파이썬 인터프리터가 설치될 때 .pyz와 .pyzw 파일 확장자를 등록한다는 점에서 myapp.pyz[w] 파일은 실행 파일입니다.

경고

응용 프로그램이 C 확장을 포함하는 패키지에 의존하면, 해당 패키지는 zip 파일에서 실행할 수 없습니다 (이것은 OS 제한 사항인데, OS 로더가 로드 할 수 있으려면 실행 코드는 파일 시스템에 있어야만 합니다). 이 경우, zip 파일에서 해당 종속성을 제외하고, 사용자가 파일을 설치하도록 요구하거나, zip 파일과 함께 제공하고 __main__.py에 코드를 추가하여 sys.path에 압축 해제된 모듈을 포함하는 디렉터리를 포함할 수 있습니다. 이 경우, 대상 아키텍처에 적합한 바이너리를 제공해야 합니다 (그리고 아마도 사용자 컴퓨터를 기반으로 실행 시간에 sys.path에 추가할 올바른 버전을 선택해야 합니다).

파이썬 Zip 응용 프로그램 아카이브 형식

파이썬은 버전 2.6부터 __main__.py 파일이 포함된 zip 파일을 실행할 수 있었습니다. 파이썬에서 실행되려면, 응용 프로그램 아카이브는 응용 프로그램의 진입점으로 실행될 __main__.py 파일이 포함된 표준 zip 파일이어야 합니다. 모든 파이썬 스크립트와 마찬가지로, 스크립트의 부모(이 경우 zip 파일)가 sys.path에 배치되므로 zip 파일에서 추가 모듈을 임포트 할 수 있습니다.

zip 파일 형식은 임의의 데이터를 zip 파일 앞에 추가할 수 있도록 합니다. zip 응용 프로그램 형식은 이 기능을 사용하여 표준 POSIX “셔뱅(shebang)” 줄을 파일 앞에 추가합니다 (#!/path/to/interpreter).

따라서 공식적으로 파이썬 zip 응용 프로그램 형식은 다음과 같습니다:

An optional shebang line, containing the characters b'#!' followed by an interpreter name, and then a newline (b'\n') character. The interpreter name can be anything acceptable to the OS “shebang” processing, or the Python launcher on Windows. The interpreter should be encoded in UTF-8 on Windows, and in sys.getfilesystemencoding() on POSIX.

zipfile 모듈에 의해 생성된 표준 zip 파일 데이터. zipfile 내용은 반드시 __main__.py라는 파일을 포함해야 합니다 (zip 파일의 “루트”에 있어야 합니다 - 즉, 서브 디렉터리에 있을 수 없습니다). zip 파일 데이터는 압축되거나 그렇지 않을 수 있습니다.

응용 프로그램 아카이브에 셔뱅 줄이 있으면, POSIX 시스템에서 직접 실행될 수 있도록 실행 파일 비트를 설정할 수 있습니다.

이 모듈의 도구를 사용하여 응용 프로그램 아카이브를 만들 필요는 없습니다 - 모듈은 편의를 위한 것입니다. 하지만 어떤 방법으로 만들었든 위 형식의 아카이브는 파이썬에서 허용됩니다.

파이썬 실행시간 서비스

이 장에서 설명하는 모듈들은 파이썬 인터프리터와 그 환경과의 상호 작용과 관련된 다양한 서비스를 제공합니다. 다음은 개요입니다:

sys — System-specific parameters and functions

abiflags

addaudithook()

argv

audit()

base_exec_prefix

base_prefix

byteorder

builtin_module_names

call_tracing()

copyright

_clear_type_cache()

_clear_internal_caches()

_current_frames()

_current_exceptions()

breakpointhook()

_debugmallocstats()

dllhandle

displayhook()

dont_write_bytecode

_emscripten_info

emscripten_version

runtime

pthreads

shared_memory

pycache_prefix

excepthook()

__breakpointhook__

__displayhook__

__excepthook__

__unraisablehook__

exception()

exc_info()

exec_prefix

executable

exit()

flags

debug

inspect

interactive

isolated

optimize

dont_write_bytecode

no_user_site

no_site

ignore_environment

verbose

bytes_warning

quiet

hash_randomization

dev_mode

utf8_mode

safe_path

int_max_str_digits

warn_default_encoding

float_info

epsilon

dig

mant_dig

max

max_exp

max_10_exp

min

min_exp

min_10_exp

radix

rounds

float_repr_style

getallocatedblocks()

getunicodeinternedsize()

getandroidapilevel()

getdefaultencoding()

getdlopenflags()

getfilesystemencoding()

getfilesystemencodeerrors()

get_int_max_str_digits()

getrefcount()

getrecursionlimit()

getsizeof()

getswitchinterval()

_getframe()

_getframemodulename()

getobjects()

getprofile()

gettrace()

getwindowsversion()

get_asyncgen_hooks()

get_coroutine_origin_tracking_depth()

hash_info

width

modulus

inf

nan

imag

algorithm

hash_bits

seed_bits

hexversion

implementation

int_info

bits_per_digit

sizeof_digit

default_max_str_digits

str_digits_check_threshold

__interactivehook__

intern()

_is_gil_enabled()

is_finalizing()

last_exc

_is_interned()

last_type

last_value

last_traceback

maxsize

maxunicode

meta_path

modules

orig_argv

path

path_hooks

path_importer_cache

platform

platlibdir

prefix

ps1

ps2

setdlopenflags()

set_int_max_str_digits()

setprofile()

setrecursionlimit()

setswitchinterval()

settrace()

set_asyncgen_hooks()

set_coroutine_origin_tracking_depth()

activate_stack_trampoline()

deactivate_stack_trampoline()

is_stack_trampoline_active()

_enablelegacywindowsfsencoding()

stdin

stdout

stderr

__stdin__

__stdout__

__stderr__

stdlib_module_names

thread_info

name

lock

version

tracebacklimit

unraisablehook()

version

api_version

version_info

warnoptions

winver

_xoptions

sys.monitoring — Execution event monitoring

Tool identifiers

Registering and using tools

use_tool_id()

clear_tool_id()

free_tool_id()

get_tool()

Events

Local events

Ancillary events

Other events

The STOP_ITERATION event

Turning events on and off

Setting events globally

get_events()

set_events()

Per code object events

get_local_events()

set_local_events()

Disabling events

DISABLE

restart_events()

Registering callback functions

register_callback()

Callback function arguments

MISSING

sysconfig — Provide access to Python’s configuration information

구성 변수

get_config_vars()

get_config_var()

설치 경로

User scheme

posix_user

nt_user

osx_framework_user

Home scheme

posix_home

Prefix scheme

posix_prefix

nt

Installation path functions

get_scheme_names()

get_default_scheme()

get_preferred_scheme()

_get_preferred_schemes()

get_path_names()

get_path()

get_paths()

기타 함수

get_python_version()

get_platform()

is_python_build()

parse_config_h()

get_config_h_filename()

get_makefile_filename()

sysconfig 를 스크립트로 사용하기

builtins — Built-in objects

__main__ — Top-level code environment

__name__ == '__main__'

What is the “top-level code environment”?

Idiomatic Usage

Packaging Considerations

__main__.py in Python Packages

Idiomatic Usage

import __main__

warnings — Warning control

경고 범주

경고 필터

Repeated Warning Suppression Criteria

경고 필터 설명

기본 경고 필터

기본 필터 재정의

일시적인 경고 억제

경고 테스트

새 버전의 종속성에 대한 코드 갱신

사용 가능한 함수

warn()

warn_explicit()

showwarning()

formatwarning()

filterwarnings()

simplefilter()

resetwarnings()

deprecated()

사용 가능한 컨텍스트 관리자

catch_warnings

dataclasses — Data Classes

Module contents

dataclass()

field()

Field

fields()

asdict()

astuple()

make_dataclass()

replace()

is_dataclass()

MISSING

KW_ONLY

FrozenInstanceError

초기화 후처리

__post_init__()

클래스 변수

초기화 전용 변수

고정 인스턴스

계승

Re-ordering of keyword-only parameters in __init__()

기본 팩토리 함수

가변 기본값

Descriptor-typed fields

contextlib — with 문 컨텍스트를 위한 유틸리티

유틸리티

AbstractContextManager

AbstractAsyncContextManager

contextmanager()

asynccontextmanager()

closing()

aclosing()

nullcontext()

suppress()

redirect_stdout()

redirect_stderr()

chdir()

ContextDecorator

AsyncContextDecorator

ExitStack

enter_context()

push()

callback()

pop_all()

close()

AsyncExitStack

enter_async_context()

push_async_exit()

push_async_callback()

aclose()

예제와 조리법

일정하지 않은 수의 컨텍스트 관리자 지원

__enter__ 메서드에서 발생하는 예외 잡기

__enter__ 구현에서 정리하기

try-finally와 플래그 변수 사용 교체하기

함수 데코레이터로 컨텍스트 관리자 사용하기

일회용, 재사용 가능 및 재진입 가능 컨텍스트 관리자

재진입 가능 컨텍스트 관리자

재사용 가능 컨텍스트 관리자

abc — Abstract Base Classes

ABC

ABCMeta

register()

__subclasshook__()

abstractmethod()

abstractclassmethod()

abstractstaticmethod()

abstractproperty()

get_cache_token()

update_abstractmethods()

atexit — Exit handlers

register()

unregister()

atexit 예제

traceback — Print or retrieve a stack traceback

Module-Level Functions

print_tb()

print_exception()

print_exc()

print_last()

print_stack()

extract_tb()

extract_stack()

format_list()

format_exception_only()

format_exception()

format_exc()

format_tb()

format_stack()

clear_frames()

walk_stack()

walk_tb()

TracebackException Objects

TracebackException

__cause__

__context__

exceptions

__suppress_context__

__notes__

stack

exc_type

exc_type_str

filename

lineno

end_lineno

text

offset

end_offset

msg

from_exception()

print()

format()

format_exception_only()

StackSummary Objects

StackSummary

extract()

from_list()

format()

format_frame_summary()

FrameSummary Objects

FrameSummary

filename

lineno

name

line

Examples of Using the Module-Level Functions

Examples of Using TracebackException

__future__ — Future statement definitions

Module Contents

_Feature

getOptionalRelease()

getMandatoryRelease()

compiler_flag

gc — Garbage Collector interface

enable()

disable()

isenabled()

collect()

set_debug()

get_debug()

get_objects()

get_stats()

set_threshold()

get_count()

get_threshold()

get_referrers()

get_referents()

is_tracked()

is_finalized()

freeze()

unfreeze()

get_freeze_count()

garbage

callbacks

DEBUG_STATS

DEBUG_COLLECTABLE

DEBUG_UNCOLLECTABLE

DEBUG_SAVEALL

DEBUG_LEAK

inspect — Inspect live objects

형과 멤버

getmembers()

getmembers_static()

getmodulename()

ismodule()

isclass()

ismethod()

ispackage()

isfunction()

isgeneratorfunction()

isgenerator()

iscoroutinefunction()

markcoroutinefunction()

iscoroutine()

isawaitable()

isasyncgenfunction()

isasyncgen()

istraceback()

isframe()

iscode()

isbuiltin()

ismethodwrapper()

isroutine()

isabstract()

ismethoddescriptor()

isdatadescriptor()

isgetsetdescriptor()

ismemberdescriptor()

소스 코드 가져오기

getdoc()

getcomments()

getfile()

getmodule()

getsourcefile()

getsourcelines()

getsource()

cleandoc()

Signature 객체로 콜러블 검사하기

signature()

Signature

empty

parameters

return_annotation

bind()

bind_partial()

replace()

format()

from_callable()

Parameter

empty

name

default

annotation

kind

description

replace()

BoundArguments

arguments

args

kwargs

signature

apply_defaults()

클래스와 함수

getclasstree()

getfullargspec()

getargvalues()

formatargvalues()

getmro()

getcallargs()

getclosurevars()

unwrap()

get_annotations()

인터프리터 스택

FrameInfo

frame

filename

lineno

function

code_context

index

positions

Traceback

filename

lineno

function

code_context

index

positions

getframeinfo()

getouterframes()

getinnerframes()

currentframe()

stack()

trace()

정적으로 어트리뷰트 가져오기

getattr_static()

Current State of Generators, Coroutines, and Asynchronous Generators

getgeneratorstate()

getcoroutinestate()

getasyncgenstate()

getgeneratorlocals()

getcoroutinelocals()

getasyncgenlocals()

코드 객체 비트 플래그

CO_OPTIMIZED

CO_NEWLOCALS

CO_VARARGS

CO_VARKEYWORDS

CO_NESTED

CO_GENERATOR

CO_COROUTINE

CO_ITERABLE_COROUTINE

CO_ASYNC_GENERATOR

CO_HAS_DOCSTRING

Buffer flags

BufferFlags

SIMPLE

WRITABLE

FORMAT

ND

STRIDES

C_CONTIGUOUS

F_CONTIGUOUS

ANY_CONTIGUOUS

INDIRECT

CONTIG

CONTIG_RO

STRIDED

STRIDED_RO

RECORDS

RECORDS_RO

FULL

FULL_RO

READ

WRITE

명령 줄 인터페이스

annotationlib — Functionality for introspecting annotations

Annotation semantics

Classes

Format

VALUE

FORWARDREF

STRING

VALUE_WITH_FAKE_GLOBALS

ForwardRef

__forward_arg__

evaluate()

Functions

annotations_to_string()

call_annotate_function()

call_evaluate_function()

get_annotate_function()

get_annotations()

value_to_string()

site — Site-specific configuration hook

sitecustomize

usercustomize

Readline 구성

모듈 내용

PREFIXES

ENABLE_USER_SITE

USER_SITE

USER_BASE

main()

addsitedir()

getsitepackages()

getuserbase()

getusersitepackages()

명령 줄 인터페이스

sys — System-specific parameters and functions

이 모듈은 인터프리터에 의해 사용되거나 유지되는 일부 변수와 인터프리터와 강하게 상호 작용하는 함수에 대한 액세스를 제공합니다. 항상 사용 가능합니다.

sys.abiflags

표준 configure 스크립트를 사용하여 파이썬을 빌드한 POSIX 시스템에서, 이것은 PEP 3149 [https://peps.python.org/pep-3149/]에 지정된 ABI 플래그를 포함합니다.

Added in version 3.2.

버전 3.8에서 변경: 기본 플래그는 빈 문자열이 되었습니다 (pymalloc을 위한 m 플래그가 제거되었습니다).

Availability: Unix.

sys.addaudithook(hook)

Append the callable hook to the list of active auditing hooks for the current (sub)interpreter.

When an auditing event is raised through the sys.audit() function, each hook will be called in the order it was added with the event name and the tuple of arguments. Native hooks added by PySys_AddAuditHook() are called first, followed by hooks added in the current (sub)interpreter. Hooks can then log the event, raise an exception to abort the operation, or terminate the process entirely.

Note that audit hooks are primarily for collecting information about internal or otherwise unobservable actions, whether by Python or libraries written in Python. They are not suitable for implementing a “sandbox”. In particular, malicious code can trivially disable or bypass hooks added using this function. At a minimum, any security-sensitive hooks must be added using the C API PySys_AddAuditHook() before initialising the runtime, and any modules allowing arbitrary memory modification (such as ctypes) should be completely removed or closely monitored.

sys.addaudithook()을 호출하면 스스로 인자 없이 sys.addaudithook이라는 이름의 감사 이벤트를 발생시킵니다. 기존 훅에서 RuntimeError에서 파생된 예외가 발생하면, 새 훅이 추가되지 않고 예외가 억제됩니다. 결과적으로, 호출자는 기존의 모든 훅을 제어하지 않는 한 훅이 추가되었다고 가정할 수 없습니다.

CPython이 발생시키는 모든 이벤트에 대해서는 감사 이벤트 표를, 원래 디자인 논의는 PEP 578 [https://peps.python.org/pep-0578/]을 참조하십시오.

Added in version 3.8.

버전 3.8.1에서 변경: Exception에서 파생되었지만 RuntimeError가 아닌 예외는 더는 억제되지 않습니다.

CPython 구현 상세: 추적(tracing)이 활성화되었을 때 (settrace()를 참조하십시오), 파이썬 훅은 콜러블에 참값으로 설정된 __cantrace__ 멤버가 있을 때만 추적합니다. 그렇지 않으면, 추적 함수는 훅을 건너뜁니다.

sys.argv

파이썬 스크립트에 전달된 명령 줄 인자 리스트. argv[0]은 스크립트 이름입니다 (전체 경로명인지는 운영 체제에 따라 다릅니다). 인터프리터에 -c 명령 줄 옵션을 사용하여 명령이 실행되었으면, argv[0]은 문자열 '-c'로 설정됩니다. 파이썬 인터프리터에 스크립트 이름이 전달되지 않으면, argv[0]은 빈 문자열입니다.

표준 입력이나 명령 줄에 제공된 파일 목록을 루핑 하려면, fileinput 모듈을 참조하십시오.

See also sys.orig_argv.

참고

유닉스에서, 명령 줄 인자는 OS에서 바이트열로 전달됩니다. 파이썬은 이것들을 파일 시스템 인코딩과 “surrogateescape” 에러 처리기로 디코딩합니다. 원본 바이트열이 필요할 때, [os.fsencode(arg) for arg in sys.argv]로 얻을 수 있습니다.

sys.audit(event, *args)

활성 감사 훅으로 감사 이벤트를 발생시킵니다. event는 이벤트를 식별하는 문자열이고, args는 이벤트에 대한 추가 정보를 갖는 선택적 인자를 포함할 수 있습니다. 주어진 이벤트에 대한 인자의 수와 형은 공개된 안정 API로 간주하며 배포 간에 수정되지 않아야 합니다.

예를 들어, 한 감사 이벤트의 이름은 os.chdir입니다. 이 이벤트에는 요청된 새 작업 디렉터리를 포함하는 path라는 인자가 하나 있습니다.

sys.audit()는 이벤트 이름과 인자들을 전달하여 기존 감사 훅들을 호출하고, 어떤 훅에서건 발생한 첫 번째 예외를 발생시킵니다. 일반적으로, 예외가 발생하면, 처리되지 않아야 하며 가능한 한 빨리 프로세스를 종료해야 합니다. 이렇게 하면 훅 구현이 특정 이벤트에 반응하는 방법을 결정할 수 있습니다: 단순히 이벤트를 로그 하거나 예외를 발생 시켜 연산을 중단 할 수 있습니다.

훅은 sys.addaudithook()이나 PySys_AddAuditHook() 함수를 사용하여 추가됩니다.

이 함수의 네이티브 동등 물은 PySys_Audit()입니다. 가능하면 네이티브 함수를 사용하는 것이 좋습니다.

CPython이 발생시키는 모든 이벤트에 대해서는 감사 이벤트 표를 참조하십시오.

Added in version 3.8.

sys.base_exec_prefix

Equivalent to exec_prefix, but refering to the base Python installation.

When running under Virtual Environments, exec_prefix gets overwritten to the virtual environment prefix. base_exec_prefix, conversely, does not change, and always points to the base Python installation. Refer to Virtual Environments for more information.

Added in version 3.3.

sys.base_prefix

Equivalent to prefix, but refering to the base Python installation.

When running under virtual environment, prefix gets overwritten to the virtual environment prefix. base_prefix, conversely, does not change, and always points to the base Python installation. Refer to Virtual Environments for more information.

Added in version 3.3.

sys.byteorder

네이티브 바이트 순서의 표시기. 이는 빅 엔디안(최상위 바이트 먼저) 플랫폼에서 'big' 값을, 리틀 엔디안(최하위 바이트 먼저) 플랫폼에서 'little'을 갖습니다.

sys.builtin_module_names

A tuple of strings containing the names of all modules that are compiled into this Python interpreter. (This information is not available in any other way — modules.keys() only lists the imported modules.)

See also the sys.stdlib_module_names list.

sys.call_tracing(func, args)

Call func(*args), while tracing is enabled. The tracing state is saved, and restored afterwards. This is intended to be called from a debugger from a checkpoint, to recursively debug or profile some other code.

Tracing is suspended while calling a tracing function set by settrace() or setprofile() to avoid infinite recursion. call_tracing() enables explicit recursion of the tracing function.

sys.copyright

파이썬 인터프리터와 관련된 저작권이 포함된 문자열.

sys._clear_type_cache()

내부 형 캐시를 지웁니다. 형 캐시는 어트리뷰트와 메서드 조회 속도를 높이는 데 사용됩니다. 참조 누수 디버깅 중에 불필요한 참조를 제거하기 위해서 만 이 함수를 사용하십시오.

이 함수는 내부와 특수 목적으로만 사용해야 합니다.

버전 3.13부터 폐지됨: Use the more general _clear_internal_caches() function instead.

sys._clear_internal_caches()

Clear all internal performance-related caches. Use this function only to release unnecessary references and memory blocks when hunting for leaks.

Added in version 3.13.

sys._current_frames()

함수가 호출될 때 각 스레드의 식별자를 해당 스레드에서 현재 활성화된 최상위 스택 프레임에 매핑하는 딕셔너리를 반환합니다. traceback 모듈의 함수는 이러한 프레임을 주면 호출 스택을 빌드할 수 있음에 유의하십시오.

이것은 교착 상태 디버깅에 가장 유용합니다: 이 함수는 교착 상태에 빠진 스레드의 협력을 필요로하지 않으며, 이러한 스레드의 호출 스택은 교착 상태를 유지하는 한 고정됩니다. 교착 상태가 아닌 스레드에 대해 반환된 프레임은 호출하는 코드가 프레임을 검사할 때까지 해당 스레드의 현재 활동과 관련이 없을 수 있습니다.

이 함수는 내부와 특수 목적으로만 사용해야 합니다.

인자 없이 감사 이벤트 sys._current_frames를 발생시킵니다.

sys._current_exceptions()

Return a dictionary mapping each thread’s identifier to the topmost exception currently active in that thread at the time the function is called. If a thread is not currently handling an exception, it is not included in the result dictionary.

This is most useful for statistical profiling.

이 함수는 내부와 특수 목적으로만 사용해야 합니다.

Raises an auditing event sys._current_exceptions with no arguments.

버전 3.12에서 변경: Each value in the dictionary is now a single exception instance, rather than a 3-tuple as returned from sys.exc_info().

sys.breakpointhook()

이 훅 함수는 내장 breakpoint()에 의해 호출됩니다. 기본적으로, pdb 디버거로 떨어뜨리지만, 다른 함수로 설정하여 사용할 디버거를 선택할 수 있습니다.

이 함수의 서명은 그것이 호출하는 것에 의존합니다. 예를 들어, 기본 바인딩(예를 들어 pdb.set_trace())에는 인자가 필요하지 않지만, 추가 인자(위치 및/또는 키워드)를 기대하는 함수에 바인딩할 수 있습니다. 내장 breakpoint() 함수는 *args와 **kws를 그대로 전달합니다. breakpointhooks()가 반환하는 것이 breakpoint()에서 반환됩니다.

기본 구현은 먼저 환경 변수 PYTHONBREAKPOINT를 참조합니다. 이것이 "0"으로 설정되면, 이 함수는 즉시 반환합니다; 즉, 아무런 일도 하지 않습니다. 환경 변수가 설정되지 않거나 빈 문자열로 설정되면, pdb.set_trace()가 호출됩니다. 그렇지 않으면 이 변수는 파이썬의 점으로 표현한 임포트 표기법(예를 들어 package.subpackage.module.function)을 사용하여 실행할 함수의 이름을 지정해야 합니다. 이 경우, package.subpackage.module이 임포트 되고 결과 모듈에는 function()이라는 이름의 콜러블이 있어야 합니다. 이것이 *args 및 **kws를 전달하여 실행되며, function()이 반환하는 것을 sys.breakpointhook()이 내장 breakpoint() 함수로 반환합니다.

PYTHONBREAKPOINT로 이름이 지정된 콜러블을 임포트 하는 도중에 문제가 발생하면, RuntimeWarning이 보고되고 중단점은 무시됨에 유의하십시오.

또한 sys.breakpointhook()이 프로그래밍 방식으로 재정의되면, PYTHONBREAKPOINT는 참조되지 않음에 유의하십시오.

Added in version 3.7.

sys._debugmallocstats()

CPython의 메모리 할당자 상태에 대한 저수준 정보를 stderr에 인쇄합니다.

If Python is built in debug mode (configure --with-pydebug option), it also performs some expensive internal consistency checks.

Added in version 3.3.

CPython 구현 상세: 이 함수는 CPython 전용입니다. 정확한 출력 형식은 여기에 정의되어 있지 않으며, 변경될 수 있습니다.

sys.dllhandle

파이썬 DLL의 핸들을 지정하는 정수.

Availability: Windows.

sys.displayhook(value)

value가 None이 아니면, 이 함수는 repr(value)를 sys.stdout으로 인쇄하고, value를 builtins._에 저장합니다. repr(value)를 sys.stdout.errors 에러 처리기(아마도 'strict')로 sys.stdout.encoding으로 인코딩할 수 없으면, 'backslashreplace' 에러 처리기를 사용하여 sys.stdout.encoding으로 인코딩합니다.

sys.displayhook은 대화형 파이썬 세션에서 입력한 표현식을 평가한 결과에 대해 호출됩니다. sys.displayhook에 다른 1-인자 함수를 대입하여 이러한 값의 표시를 사용자 정의할 수 있습니다.

의사 코드:

def displayhook(value):
    if value is None:
        return
    # Set '_' to None to avoid recursion
    builtins._ = None
    text = repr(value)
    try:
        sys.stdout.write(text)
    except UnicodeEncodeError:
        bytes = text.encode(sys.stdout.encoding, 'backslashreplace')
        if hasattr(sys.stdout, 'buffer'):
            sys.stdout.buffer.write(bytes)
        else:
            text = bytes.decode(sys.stdout.encoding, 'strict')
            sys.stdout.write(text)
    sys.stdout.write("\n")
    builtins._ = value

버전 3.2에서 변경: UnicodeEncodeError 에 'backslashreplace' 에러 처리기를 사용합니다.

sys.dont_write_bytecode

이것이 참이면, 파이썬은 소스 모듈을 임포트 할 때 .pyc 파일을 쓰려고 하지 않습니다. 이 값은 -B 명령 줄 옵션과 PYTHONDONTWRITEBYTECODE 환경 변수에 따라 초기에 True나 False로 설정되지만, 바이트 코드 파일 생성을 제어하기 위해 직접 설정할 수 있습니다.

sys._emscripten_info

A named tuple holding information about the environment on the wasm32-emscripten platform. The named tuple is provisional and may change in the future.

_emscripten_info.emscripten_version

Emscripten version as tuple of ints (major, minor, micro), e.g. (3, 1, 8).

_emscripten_info.runtime

Runtime string, e.g. browser user agent, 'Node.js v14.18.2', or 'UNKNOWN'.

_emscripten_info.pthreads

True if Python is compiled with Emscripten pthreads support.

_emscripten_info.shared_memory

True if Python is compiled with shared memory support.

Availability: Emscripten.

Added in version 3.11.

sys.pycache_prefix

If this is set (not None), Python will write bytecode-cache .pyc files to (and read them from) a parallel directory tree rooted at this directory, rather than from __pycache__ directories in the source code tree. Any __pycache__ directories in the source code tree will be ignored and new .pyc files written within the pycache prefix. Thus if you use compileall as a pre-build step, you must ensure you run it with the same pycache prefix (if any) that you will use at runtime.

상대 경로는 현재 작업 디렉터리를 기준으로 해석됩니다.

이 값은 초기에 -X pycache_prefix=PATH 명령 줄 옵션이나 PYTHONPYCACHEPREFIX 환경 변수(명령 줄이 우선합니다)의 값을 기반으로 설정됩니다. 둘 다 설정되지 않으면, None입니다.

Added in version 3.8.

sys.excepthook(type, value, traceback)

이 함수는 주어진 트레이스백(traceback)과 예외를 sys.stderr에 인쇄합니다.

When an exception other than SystemExit is raised and uncaught, the interpreter calls sys.excepthook with three arguments, the exception class, exception instance, and a traceback object. In an interactive session this happens just before control is returned to the prompt; in a Python program this happens just before the program exits. The handling of such top-level exceptions can be customized by assigning another three-argument function to sys.excepthook.

잡히지 않은 예외가 발생할 때 인자 hook, type, value, traceback로 감사 이벤트 sys.excepthook을 발생시킵니다. 아무런 훅도 설정되지 않았으면, hook은 None 일 수 있습니다. 훅이 RuntimeError에서 파생된 예외를 발생시키면 훅 호출이 억제됩니다. 그렇지 않으면, 감사 훅 예외는 발생시킬 수 없는 것(unraisable)으로 보고되고 sys.excepthook이 호출됩니다.

더 보기

sys.unraisablehook() 함수는 발생시킬 수 없는 예외(unraisable exception)를 다루고 threading.excepthook() 함수는 threading.Thread.run()이 발생시킨 예외를 다룹니다.

sys.__breakpointhook__

sys.__displayhook__

sys.__excepthook__

sys.__unraisablehook__

이러한 객체는 프로그램 시작 시 breakpointhook, displayhook, excepthook 및 unraisablehook 의 원래 값을 포함합니다. breakpointhook, displayhook 및 excepthook, unraisablehook 이 파손되거나 대체 객체로 교체될 때 복원 할 수 있도록 저장됩니다.

Added in version 3.7: __breakpointhook__

Added in version 3.8: __unraisablehook__

sys.exception()

This function, when called while an exception handler is executing (such as an except or except* clause), returns the exception instance that was caught by this handler. When exception handlers are nested within one another, only the exception handled by the innermost handler is accessible.

If no exception handler is executing, this function returns None.

Added in version 3.11.

sys.exc_info()

This function returns the old-style representation of the handled exception. If an exception e is currently handled (so exception() would return e), exc_info() returns the tuple (type(e), e, e.__traceback__). That is, a tuple containing the type of the exception (a subclass of BaseException), the exception itself, and a traceback object which typically encapsulates the call stack at the point where the exception last occurred.

If no exception is being handled anywhere on the stack, this function return a tuple containing three None values.

버전 3.11에서 변경: The type and traceback fields are now derived from the value (the exception instance), so when an exception is modified while it is being handled, the changes are reflected in the results of subsequent calls to exc_info().

sys.exec_prefix

플랫폼 특정 파이썬 파일이 설치되는 사이트 특정 디렉터리 접두사를 제공하는 문자열; 기본적으로, 이것은 '/usr/local'이기도 합니다. configure 스크립트에 --exec-prefix 인자를 사용하여 빌드 시 설정할 수 있습니다. 구체적으로, 모든 구성 파일(예를 들어 pyconfig.h 헤더 파일)은 디렉터리 exec_prefix/lib/pythonX.Y/config에 설치되고, 공유 라이브러리 모듈은 exec_prefix/lib/pythonX.Y/lib-dynload에 설치됩니다. 여기서 X.Y는 파이썬의 버전 번호입니다, 예를 들어 3.2.

참고

If a virtual environment is in effect, this exec_prefix will point to the virtual environment. The value for the Python installation will still be available, via base_exec_prefix. Refer to Virtual Environments for more information.

버전 3.14에서 변경: When running under a virtual environment, prefix and exec_prefix are now set to the virtual environment prefix by the path initialization, instead of site. This means that prefix and exec_prefix always point to the virtual environment, even when site is disabled (-S).

sys.executable

의미가 있는 시스템에서, 파이썬 인터프리터를 위한 실행 바이너리의 절대 경로를 제공하는 문자열. 파이썬이 실행 파일의 실제 경로를 검색할 수 없으면, sys.executable은 빈 문자열이거나 None입니다.

sys.exit([arg])

Raise a SystemExit exception, signaling an intention to exit the interpreter.

선택적 인자 arg는 종료 상태(기본값은 0)를 나타내는 정수나 다른 형의 객체일 수 있습니다. 정수면, 0은 “성공적인 종료”로 간주하고, 0이 아닌 값은 셸 등이 “비정상 종료”로 간주합니다. 대부분 시스템은 0–127 범위를 요구하고, 그렇지 않으면 정의되지 않은 결과를 생성합니다. 일부 시스템에는 특정 종료 코드에 특정 의미를 지정하는 규칙이 있지만, 일반적으로 잘 개발되지 않은 상태입니다; 유닉스 프로그램은 일반적으로 명령 줄 구문 에러에 2를, 다른 모든 종류의 에러에 1을 사용합니다. 다른 형의 객체가 전달되면, None은 0을 전달하는 것과 동등하며, 다른 모든 객체는 stderr로 인쇄되고 종료 코드 1을 만듭니다. 특히, sys.exit("some error message")는 에러가 발생할 때 프로그램을 종료하는 빠른 방법입니다.

Since exit() ultimately “only” raises an exception, it will only exit the process when called from the main thread, and the exception is not intercepted. Cleanup actions specified by finally clauses of try statements are honored, and it is possible to intercept the exit attempt at an outer level.

버전 3.6에서 변경: 파이썬 인터프리터가 SystemExit를 잡은 후 정리할 때 에러가 발생하면 (가령 표준 스트림에 버퍼링 된 데이터를 플러시할 때의 에러), 종료 상태가 120으로 변경됩니다.

sys.flags

네임드 튜플 flags는 명령 줄 플래그의 상태를 노출합니다. 어트리뷰트는 읽기 전용입니다.

flags.debug

-d

flags.inspect

-i

flags.interactive

-i

flags.isolated

-I

flags.optimize

-O 또는 -OO

flags.dont_write_bytecode

-B

flags.no_user_site

-s

flags.no_site

-S

flags.ignore_environment

-E

flags.verbose

-v

flags.bytes_warning

-b

flags.quiet

-q

flags.hash_randomization

-R

flags.dev_mode

-X dev (파이썬 개발 모드)

flags.utf8_mode

-X utf8

flags.safe_path

-P

flags.int_max_str_digits

-X int_max_str_digits (integer string conversion length limitation)

flags.warn_default_encoding

-X warn_default_encoding

버전 3.2에서 변경: 새로운 -q 플래그에 대한 quiet 어트리뷰트가 추가되었습니다.

Added in version 3.2.3: hash_randomization 어트리뷰트.

버전 3.3에서 변경: 사용되지 않는 division_warning 어트리뷰트를 제거했습니다.

버전 3.4에서 변경: -I isolated 플래그에 대한 isolated 어트리뷰트가 추가되었습니다.

버전 3.7에서 변경: 새로운 파이썬 개발자 모드에 대한 dev_mode 어트리뷰트와 새로운 -X utf8 플래그에 대한 utf8_mode 어트리뷰트가 추가되었습니다.

버전 3.10에서 변경: Added warn_default_encoding attribute for -X warn_default_encoding flag.

버전 3.11에서 변경: Added the safe_path attribute for -P option.

버전 3.11에서 변경: Added the int_max_str_digits attribute.

sys.float_info

float 형에 대한 정보를 담은 네임드 튜플. 정밀도와 내부 표현에 대한 저수준 정보를 포함합니다. 값은 ‘C’ 프로그래밍 언어의 표준 헤더 파일 float.h에 정의된 다양한 부동 소수점 상수에 해당합니다; 자세한 내용은 1999 ISO/IEC C 표준 [C99] 의 섹션 5.2.4.2.2 ‘Characteristics of floating types’를 참조하십시오.

Attributes of the float_info named tuple

어트리뷰트

float.h 매크로

설명

float_info.epsilon

DBL_EPSILON

difference between 1.0 and the least value greater than 1.0 that is representable as a float.

math.ulp()도 참조하십시오.

float_info.dig

DBL_DIG

The maximum number of decimal digits that can be faithfully represented in a float; see below.

float_info.mant_dig

DBL_MANT_DIG

Float precision: the number of base-radix digits in the significand of a float.

float_info.max

DBL_MAX

The maximum representable positive finite float.

float_info.max_exp

DBL_MAX_EXP

The maximum integer e such that radix**(e-1) is a representable finite float.

float_info.max_10_exp

DBL_MAX_10_EXP

The maximum integer e such that 10**e is in the range of representable finite floats.

float_info.min

DBL_MIN

The minimum representable positive normalized float.

math.ulp(0.0)를 사용하여 가장 작은 양의 정규화되지 않은(denormalized) 표현 가능한 float를 얻습니다.

float_info.min_exp

DBL_MIN_EXP

The minimum integer e such that radix**(e-1) is a normalized float.

float_info.min_10_exp

DBL_MIN_10_EXP

The minimum integer e such that 10**e is a normalized float.

float_info.radix

FLT_RADIX

The radix of exponent representation.

float_info.rounds

FLT_ROUNDS

An integer representing the rounding mode for floating-point arithmetic. This reflects the value of the system FLT_ROUNDS macro at interpreter startup time:

-1: indeterminable

0: toward zero

1: to nearest

2: toward positive infinity

3: toward negative infinity

All other values for FLT_ROUNDS characterize implementation-defined rounding behavior.

The attribute sys.float_info.dig needs further explanation. If s is any string representing a decimal number with at most sys.float_info.dig significant digits, then converting s to a float and back again will recover a string representing the same decimal value:

>>> import sys
>>> sys.float_info.dig
15
>>> s = '3.14159265358979'    # decimal string with 15 significant digits
>>> format(float(s), '.15g')  # convert to float and back -> same value
'3.14159265358979'

그러나 유효 숫자가 sys.float_info.dig보다 많은 문자열의 경우, 항상 그렇지는 않습니다:

>>> s = '9876543211234567'    # 16 significant digits is too many!
>>> format(float(s), '.16g')  # conversion changes value
'9876543211234568'

sys.float_repr_style

repr() 함수가 float에 대해 작동하는 방식을 나타내는 문자열. 문자열이 'short' 값을 가지면, 유한 float x의 경우, repr(x)는 float(repr(x)) == x 속성을 유지하는 짧은 문자열을 생성하는 것을 목표로 합니다. 이것은 파이썬 3.1 이상에서 일반적인 동작입니다. 그렇지 않으면, float_repr_style은 'legacy' 값을 가지며 repr(x)는 3.1 이전의 파이썬 버전에서와 같은 방식으로 작동합니다.

Added in version 3.1.

sys.getallocatedblocks()

Return the number of memory blocks currently allocated by the interpreter, regardless of their size. This function is mainly useful for tracking and debugging memory leaks. Because of the interpreter’s internal caches, the result can vary from call to call; you may have to call _clear_internal_caches() and gc.collect() to get more predictable results.

If a Python build or implementation cannot reasonably compute this information, getallocatedblocks() is allowed to return 0 instead.

Added in version 3.4.

sys.getunicodeinternedsize()

Return the number of unicode objects that have been interned.

Added in version 3.12.

sys.getandroidapilevel()

Return the build-time API level of Android as an integer. This represents the minimum version of Android this build of Python can run on. For runtime version information, see platform.android_ver().

Availability: Android.

Added in version 3.7.

sys.getdefaultencoding()

유니코드 구현에서 사용되는 현재 기본 문자열 인코딩의 이름을 반환합니다.

sys.getdlopenflags()

Return the current value of the flags that are used for dlopen() calls. Symbolic names for the flag values can be found in the os module (RTLD_xxx constants, e.g. os.RTLD_LAZY).

Availability: Unix.

sys.getfilesystemencoding()

Get the filesystem encoding: the encoding used with the filesystem error handler to convert between Unicode filenames and bytes filenames. The filesystem error handler is returned from getfilesystemencodeerrors().

For best compatibility, str should be used for filenames in all cases, although representing filenames as bytes is also supported. Functions accepting or returning filenames should support either str or bytes and internally convert to the system’s preferred representation.

올바른 인코딩과 에러 모드를 사용하려면 os.fsencode()와 os.fsdecode()를 사용해야 합니다.

The filesystem encoding and error handler are configured at Python startup by the PyConfig_Read() function: see filesystem_encoding and filesystem_errors members of PyConfig.

버전 3.2에서 변경: getfilesystemencoding() 결과는 더는 None일 수 없습니다.

버전 3.6에서 변경: 윈도우는 더는 'mbcs'를 반환한다고 보장하지 않습니다. 자세한 정보는 PEP 529 [https://peps.python.org/pep-0529/]와 _enablelegacywindowsfsencoding()를 참조하십시오.

버전 3.7에서 변경: Return 'utf-8' if the Python UTF-8 Mode is enabled.

sys.getfilesystemencodeerrors()

Get the filesystem error handler: the error handler used with the filesystem encoding to convert between Unicode filenames and bytes filenames. The filesystem encoding is returned from getfilesystemencoding().

올바른 인코딩과 에러 모드를 사용하려면 os.fsencode()와 os.fsdecode()를 사용해야 합니다.

The filesystem encoding and error handler are configured at Python startup by the PyConfig_Read() function: see filesystem_encoding and filesystem_errors members of PyConfig.

Added in version 3.6.

sys.get_int_max_str_digits()

Returns the current value for the integer string conversion length limitation. See also set_int_max_str_digits().

Added in version 3.11.

sys.getrefcount(object)

object의 참조 횟수를 반환합니다. 반환된 수는 일반적으로 예상보다 1이 높습니다. getrefcount()에 대한 인자로서의 (임시) 참조를 포함하기 때문입니다.

Note that the returned value may not actually reflect how many references to the object are actually held. For example, some objects are immortal and have a very high refcount that does not reflect the actual number of references. Consequently, do not rely on the returned value to be accurate, other than a value of 0 or 1.

버전 3.12에서 변경: Immortal objects have very large refcounts that do not match the actual number of references to the object.

sys.getrecursionlimit()

파이썬 인터프리터 스택의 최대 깊이인, 재귀 한계의 현재 값을 반환합니다. 이 제한은 무한 재귀로 인해 C 스택의 오버플로가 발생하고 파이썬이 충돌하는 것을 방지합니다. setrecursionlimit()로 설정할 수 있습니다.

sys.getsizeof(object[, default])

객체의 크기를 바이트 단위로 반환합니다. 객체는 모든 형의 객체일 수 있습니다. 모든 내장 객체는 올바른 결과를 반환하지만, 구현 특정이기 때문에 제삼자 확장에서도 그렇다고 보장할 수는 없습니다.

객체에 직접 기여한 메모리 소비만 포함하며, 이 객체가 참조하는 객체의 메모리 소비는 따지지 않습니다.

주어진 경우, 객체가 크기를 조회하는 수단을 제공하지 않으면 default가 반환됩니다. 그렇지 않으면 TypeError가 발생합니다.

getsizeof()는 객체의 __sizeof__ 메서드를 호출하고 객체가 가비지 수거기에 의해 관리되면 추가 가비지 수거기 오버헤드를 추가합니다.

See recursive sizeof recipe [https://code.activestate.com/recipes/577504-compute-memory-footprint-of-an-object-and-its-cont/] for an example of using getsizeof() recursively to find the size of containers and all their contents.

sys.getswitchinterval()

인터프리터의 “스레드 스위치 간격”을 반환합니다; setswitchinterval()을 참조하십시오.

Added in version 3.2.

sys._getframe([depth])

호출 스택에서 프레임 객체를 반환합니다. 선택적 정수 depth가 제공되면, 스택 맨 위에서 지정한 수 만큼 아래에 있는 호출의 프레임 객체를 반환합니다. 호출 스택보다 깊으면, ValueError가 발생합니다. depth의 기본값은 0이며, 호출 스택의 맨 위에 있는 프레임을 반환합니다.

Raises an auditing event sys._getframe with argument frame.

CPython 구현 상세: 이 함수는 내부와 특수 목적으로만 사용해야 합니다. 모든 파이썬 구현에 존재한다고 보장되는 것은 아닙니다.

sys._getframemodulename([depth])

Return the name of a module from the call stack. If optional integer depth is given, return the module that many calls below the top of the stack. If that is deeper than the call stack, or if the module is unidentifiable, None is returned. The default for depth is zero, returning the module at the top of the call stack.

Raises an auditing event sys._getframemodulename with argument depth.

CPython 구현 상세: 이 함수는 내부와 특수 목적으로만 사용해야 합니다. 모든 파이썬 구현에 존재한다고 보장되는 것은 아닙니다.

sys.getobjects(limit[, type])

This function only exists if CPython was built using the specialized configure option --with-trace-refs. It is intended only for debugging garbage-collection issues.

Return a list of up to limit dynamically allocated Python objects. If type is given, only objects of that exact type (not subtypes) are included.

Objects from the list are not safe to use. Specifically, the result will include objects from all interpreters that share their object allocator state (that is, ones created with PyInterpreterConfig.use_main_obmalloc set to 1 or using Py_NewInterpreter(), and the main interpreter). Mixing objects from different interpreters may lead to crashes or other unexpected behavior.

CPython 구현 상세: This function should be used for specialized purposes only. It is not guaranteed to exist in all implementations of Python.

버전 3.14에서 변경: The result may include objects from other interpreters.

sys.getprofile()

setprofile()에 의해 설정된 프로파일러 함수를 얻습니다.

sys.gettrace()

settrace()에 의해 설정된 추적 함수를 얻습니다.

CPython 구현 상세: gettrace() 함수는 디버거, 프로파일러, 커버리지 도구 등을 구현하기 위한 것입니다. 그 동작은 언어 정의의 일부라기보다는 구현 플랫폼의 일부이기 때문에, 모든 파이썬 구현에서 사용 가능한 것은 아닙니다.

sys.getwindowsversion()

현재 실행 중인 윈도우 버전을 설명하는 네임드 튜플을 반환합니다. 명명된 요소는 major, minor, build, platform, service_pack, service_pack_minor, service_pack_major, suite_mask, product_type 및 platform_version입니다. service_pack은 문자열을 포함하고 platform_version은 3-튜플이며 다른 모든 값은 정수입니다. 구성 요소는 이름으로도 액세스할 수 있어서, sys.getwindowsversion()[0] 은 sys.getwindowsversion().major와 동등합니다. 이전 버전과의 호환성을 위해, 처음 5개 요소 만 인덱싱을 통해 꺼낼 수 있습니다.

platform will be 2 (VER_PLATFORM_WIN32_NT).

product_type은 다음 값 중 하나일 수 있습니다:

상수

의미

1 (VER_NT_WORKSTATION)

시스템은 워크 스테이션입니다.

2 (VER_NT_DOMAIN_CONTROLLER)

시스템은 도메인 컨트롤러입니다.

3 (VER_NT_SERVER)

시스템은 서버이지만, 도메인 컨트롤러는 아닙니다.

This function wraps the Win32 GetVersionEx() function; see the Microsoft documentation on OSVERSIONINFOEX() for more information about these fields.

platform_version returns the major version, minor version and build number of the current operating system, rather than the version that is being emulated for the process. It is intended for use in logging rather than for feature detection.

참고

platform_version derives the version from kernel32.dll which can be of a different version than the OS version. Please use platform module for achieving accurate OS version.

Availability: Windows.

버전 3.2에서 변경: 네임드 튜플로 변경되어 service_pack_minor, service_pack_major, suite_mask 및 product_type이 추가되었습니다.

버전 3.6에서 변경: platform_version을 추가했습니다

sys.get_asyncgen_hooks()

Returns an asyncgen_hooks object, which is similar to a namedtuple of the form (firstiter, finalizer), where firstiter and finalizer are expected to be either None or functions which take an asynchronous generator iterator as an argument, and are used to schedule finalization of an asynchronous generator by an event loop.

Added in version 3.6: 자세한 내용은 PEP 525 [https://peps.python.org/pep-0525/]를 참조하십시오.

참고

이 함수는 잠정적(provisional)으로 추가되었습니다 (자세한 내용은 PEP 411 [https://peps.python.org/pep-0411/]을 참조하십시오).

sys.get_coroutine_origin_tracking_depth()

set_coroutine_origin_tracking_depth()로 설정된 현재 코루틴 원점 추적 깊이를 가져옵니다.

Added in version 3.7.

참고

이 함수는 잠정적(provisional)으로 추가되었습니다 (자세한 내용은 PEP 411 [https://peps.python.org/pep-0411/]을 참조하십시오). 디버깅 목적으로만 사용하십시오.

sys.hash_info

숫자 해시 구현의 매개 변수를 제공하는 네임드 튜플. 숫자 형의 해싱에 대한 자세한 내용은 숫자 형의 해싱을 참조하십시오.

hash_info.width

The width in bits used for hash values

hash_info.modulus

The prime modulus P used for numeric hash scheme

hash_info.inf

The hash value returned for a positive infinity

hash_info.nan

(This attribute is no longer used)

hash_info.imag

The multiplier used for the imaginary part of a complex number

hash_info.algorithm

The name of the algorithm for hashing of str, bytes, and memoryview

hash_info.hash_bits

The internal output size of the hash algorithm

hash_info.seed_bits

The size of the seed key of the hash algorithm

Added in version 3.2.

버전 3.4에서 변경: algorithm, hash_bits 및 seed_bits를 추가했습니다

sys.hexversion

단일 정수로 인코딩된 버전 번호. 이것은 비 프로덕션 릴리스에 대한 적절한 지원을 포함하여, 버전마다 증가함이 보장됩니다. 예를 들어, 파이썬 인터프리터가 버전 1.5.2 이상인지 검사하려면, 다음을 사용하십시오:

if sys.hexversion >= 0x010502F0:
    # use some advanced feature
    ...
else:
    # use an alternative implementation or warn the user
    ...

내장 hex() 함수에 전달한 결과로 볼 때만 실제로 의미가 있기 때문에 이것을 hexversion이라고 합니다. 네임드 튜플 sys.version_info는 같은 정보의 더 인간 친화적인 인코딩으로 사용될 수 있습니다.

hexversion에 대한 자세한 내용은 API와 ABI 버전 붙이기 에서 찾을 수 있습니다.

sys.implementation

현재 실행 중인 파이썬 인터프리터의 구현에 대한 정보가 포함된 객체. 모든 파이썬 구현에서 다음과 같은 어트리뷰트가 있어야 합니다.

name은 구현 식별자입니다, 예를 들어 'cpython'. 실제 문자열은 파이썬 구현에 의해 정의되지만, 소문자임이 보장됩니다.

version은 sys.version_info와 같은 형식의 네임드 튜플입니다. 파이썬 구현의 버전을 나타냅니다. 이것은 현재 실행 중인 인터프리터가 준수하는, sys.version_info가 나타내는, 특정 버전의 파이썬 언어와는 다른 의미입니다. 예를 들어, PyPy 1.8의 경우 sys.implementation.version은 sys.version_info(1, 8, 0, 'final', 0)일 수 있지만, sys.version_info는 sys.version_info(2, 7, 2, 'final', 0)입니다. CPython의 경우 참조 구현이기 때문에 같은 값입니다.

hexversion은 sys.hexversion과 같은 16진수 형식의 구현 버전입니다.

cache_tag는 임포트 절차에서 캐시 된 모듈의 파일명에 사용되는 태그입니다. 관습상, 'cpython-33'과 같이 구현 이름과 버전을 합성한 것입니다. 그러나, 파이썬 구현은 적절하다면 다른 값을 사용할 수 있습니다. cache_tag가 None으로 설정되면, 모듈 캐싱을 사용하지 않아야 함을 나타냅니다.

sys.implementation은 파이썬 구현에 고유한 추가 어트리뷰트를 포함할 수 있습니다. 이러한 비표준 어트리뷰트는 밑줄로 시작해야 하며, 여기에서는 설명하지 않습니다. 내용과 관계없이, sys.implementation은 인터프리터 실행 중이나 구현 버전 간에 변경되지 않습니다. (그러나, 파이썬 언어 버전 간에는 변경될 수 있습니다.) 자세한 정보는 PEP 421 [https://peps.python.org/pep-0421/]을 참조하십시오.

Added in version 3.3.

참고

새로운 필수 어트리뷰트를 추가하려면 일반 PEP 프로세스를 거쳐야 합니다. 자세한 정보는 PEP 421 [https://peps.python.org/pep-0421/]을 참조하십시오.

sys.int_info

파이썬의 정수 내부 표현에 대한 정보를 담고 있는 네임드 튜플. 어트리뷰트는 읽기 전용입니다.

int_info.bits_per_digit

The number of bits held in each digit. Python integers are stored internally in base 2**int_info.bits_per_digit.

int_info.sizeof_digit

The size in bytes of the C type used to represent a digit.

int_info.default_max_str_digits

The default value for sys.get_int_max_str_digits() when it is not otherwise explicitly configured.

int_info.str_digits_check_threshold

The minimum non-zero value for sys.set_int_max_str_digits(), PYTHONINTMAXSTRDIGITS, or -X int_max_str_digits.

Added in version 3.1.

버전 3.11에서 변경: Added default_max_str_digits and str_digits_check_threshold.

sys.__interactivehook__

이 어트리뷰트가 존재하면, 대화형 모드로 인터프리터가 시작될 때 해당 값이 (인자 없이) 자동으로 호출됩니다. 이것은 PYTHONSTARTUP 파일을 읽은 후에 수행되므로, 그곳에서 이 훅을 설정할 수 있습니다. site 모듈은 이것을 설정합니다.

시작 시 훅이 호출될 때 훅 객체를 인자로 감사 이벤트 cpython.run_interactivehook을 발생시킵니다.

Added in version 3.4.

sys.intern(string)

“인턴 된(interned)” 문자열 테이블에 string을 넣고, string 자신이거나 사본인 인턴 된 문자열을 반환합니다. 문자열을 인턴 하는 것은 딕셔너리 조회에서 약간의 성능 개선을 얻는 데 유용합니다 – 딕셔너리의 키가 인턴 되고. 조회 키가 인턴 되면, (해싱 후의) 키 비교는 문자열 비교 대신 포인터 비교를 수행 할 수 있습니다. 일반적으로, 파이썬 프로그램에서 사용되는 이름은 자동으로 인턴 되며, 모듈, 클래스 또는 인스턴스 어트리뷰트를 담는 데 사용되는 딕셔너리는 인턴 된 키를 갖습니다.

Interned strings are not immortal; you must keep a reference to the return value of intern() around to benefit from it.

sys._is_gil_enabled()

Return True if the GIL is enabled and False if it is disabled.

Added in version 3.13.

sys.is_finalizing()

Return True if the main Python interpreter is shutting down. Return False otherwise.

See also the PythonFinalizationError exception.

Added in version 3.5.

sys.last_exc

This variable is not always defined; it is set to the exception instance when an exception is not handled and the interpreter prints an error message and a stack traceback. Its intended use is to allow an interactive user to import a debugger module and engage in post-mortem debugging without having to re-execute the command that caused the error. (Typical use is import pdb; pdb.pm() to enter the post-mortem debugger; see pdb module for more information.)

Added in version 3.12.

sys._is_interned(string)

Return True if the given string is “interned”, False otherwise.

Added in version 3.13.

CPython 구현 상세: It is not guaranteed to exist in all implementations of Python.

sys.last_type

sys.last_value

sys.last_traceback

These three variables are deprecated; use sys.last_exc instead. They hold the legacy representation of sys.last_exc, as returned from exc_info() above.

sys.maxsize

Py_ssize_t 형의 변수가 취할 수 있는 최댓값을 제공하는 정수. 일반적으로 32비트 플랫폼에서는 2**31 - 1이고 64비트 플랫폼에서는 2**63 - 1입니다.

sys.maxunicode

가장 큰 유니코드 코드 포인트의 값을 제공하는 정수, 즉 1114111 (16진수로 0x10FFFF).

버전 3.3에서 변경: PEP 393 [https://peps.python.org/pep-0393/] 이전에는, 유니코드 문자가 UCS-2와 UCS-4 중 어는 것으로 저장되었는지를 지정하는 구성 옵션에 따라, sys.maxunicode는 0xFFFF나 0x10FFFF이었습니다.

sys.meta_path

A list of meta path finder objects that have their find_spec() methods called to see if one of the objects can find the module to be imported. By default, it holds entries that implement Python’s default import semantics. The find_spec() method is called with at least the absolute name of the module being imported. If the module to be imported is contained in a package, then the parent package’s __path__ attribute is passed in as a second argument. The method returns a module spec, or None if the module cannot be found.

더 보기

importlib.abc.MetaPathFinder

meta_path에 있는 파인더 객체의 인터페이스를 정의하는 추상 베이스 클래스.

importlib.machinery.ModuleSpec

find_spec()이 이 구상 클래스의 인스턴스를 반환해야 합니다.

버전 3.4에서 변경: Module specs were introduced in Python 3.4, by PEP 451 [https://peps.python.org/pep-0451/].

버전 3.12에서 변경: Removed the fallback that looked for a find_module() method if a meta_path entry didn’t have a find_spec() method.

sys.modules

This is a dictionary that maps module names to modules which have already been loaded. This can be manipulated to force reloading of modules and other tricks. However, replacing the dictionary will not necessarily work as expected and deleting essential items from the dictionary may cause Python to fail. If you want to iterate over this global dictionary always use sys.modules.copy() or tuple(sys.modules) to avoid exceptions as its size may change during iteration as a side effect of code or activity in other threads.

sys.orig_argv

The list of the original command line arguments passed to the Python executable.

The elements of sys.orig_argv are the arguments to the Python interpreter, while the elements of sys.argv are the arguments to the user’s program. Arguments consumed by the interpreter itself will be present in sys.orig_argv and missing from sys.argv.

Added in version 3.10.

sys.path

모듈의 검색 경로를 지정하는 문자열 리스트. 환경 변수 PYTHONPATH와 설치 종속 기본값으로 초기화되었습니다.

By default, as initialized upon program startup, a potentially unsafe path is prepended to sys.path (before the entries inserted as a result of PYTHONPATH):

python -m module command line: prepend the current working directory.

python script.py command line: prepend the script’s directory. If it’s a symbolic link, resolve symbolic links.

python -c code and python (REPL) command lines: prepend an empty string, which means the current working directory.

To not prepend this potentially unsafe path, use the -P command line option or the PYTHONSAFEPATH environment variable.

A program is free to modify this list for its own purposes. Only strings should be added to sys.path; all other data types are ignored during import.

더 보기

모듈 site. 이것은 .pth 파일을 사용하여 sys.path를 확장하는 방법에 관해 설명합니다.

sys.path_hooks

경로 인자를 취해서 경로를 위한 파인더를 만들려고 시도하는 콜러블의 리스트. 파인더를 만들 수 있으면, 콜러블이 반환하고, 그렇지 않으면 ImportError를 발생시킵니다.

원래 PEP 302 [https://peps.python.org/pep-0302/]에서 지정되었습니다.

sys.path_importer_cache

파인더 객체의 캐시 역할을 하는 딕셔너리. 키는 sys.path_hooks에 전달된 경로이며 값은 찾은 파인더입니다. 경로가 유효한 파일 시스템 경로이지만 sys.path_hooks에 파인더가 없으면 None이 저장됩니다.

원래 PEP 302 [https://peps.python.org/pep-0302/]에서 지정되었습니다.

sys.platform

A string containing a platform identifier. Known values are:

시스템

platform 값

AIX

'aix'

Android

'android'

Emscripten

'emscripten'

iOS

'ios'

리눅스

'linux'

맥 OS

'darwin'

윈도우

'win32'

윈도우/Cygwin

'cygwin'

WASI

'wasi'

On Unix systems not listed in the table, the value is the lowercased OS name as returned by uname -s, with the first part of the version as returned by uname -r appended, e.g. 'sunos5' or 'freebsd8', at the time when Python was built. Unless you want to test for a specific system version, it is therefore recommended to use the following idiom:

if sys.platform.startswith('freebsd'):
    # FreeBSD-specific code here...

버전 3.3에서 변경: On Linux, sys.platform doesn’t contain the major version anymore. It is always 'linux', instead of 'linux2' or 'linux3'.

버전 3.8에서 변경: On AIX, sys.platform doesn’t contain the major version anymore. It is always 'aix', instead of 'aix5' or 'aix7'.

버전 3.13에서 변경: On Android, sys.platform now returns 'android' rather than 'linux'.

더 보기

os.name has a coarser granularity. os.uname() gives system-dependent version information.

platform 모듈은 시스템 식별자에 대한 상세한 검사를 제공합니다.

sys.platlibdir

플랫폼별 라이브러리 디렉터리의 이름. 표준 라이브러리의 경로와 설치된 확장 모듈들의 경로를 빌드하는 데 사용됩니다.

대부분의 플랫폼에서 "lib"와 같습니다. Fedora와 SuSE에서는, 64비트 플랫폼에서 "lib64"와 같으며 다음과 같은 sys.path 경로를 제공합니다 (X.Y는 파이썬 major.minor 버전):

/usr/lib64/pythonX.Y/: 표준 라이브러리 (os 모듈의 os.py와 같은)

/usr/lib64/pythonX.Y/lib-dynload/: 표준 라이브러리의 C 확장 모듈 (errno 모듈과 같은, 정확한 파일 이름은 플랫폼에 따라 다릅니다)

/usr/lib/pythonX.Y/site-packages/ (항상 lib를 사용합니다, sys.platlibdir이 아닙니다): 제삼자 모듈

/usr/lib64/pythonX.Y/site-packages/: 제삼자 패키지의 C 확장 모듈

Added in version 3.9.

sys.prefix

A string giving the site-specific directory prefix where the platform independent Python files are installed; on Unix, the default is /usr/local. This can be set at build time with the --prefix argument to the configure script. See 설치 경로 for derived paths.

참고

If a virtual environment is in effect, this prefix will point to the virtual environment. The value for the Python installation will still be available, via base_prefix. Refer to Virtual Environments for more information.

버전 3.14에서 변경: When running under a virtual environment, prefix and exec_prefix are now set to the virtual environment prefix by the path initialization, instead of site. This means that prefix and exec_prefix always point to the virtual environment, even when site is disabled (-S).

sys.ps1

sys.ps2

인터프리터의 기본과 보조 프롬프트를 지정하는 문자열. 인터프리터가 대화형 모드일 때만 정의됩니다. 이 경우 초깃값은 '>>> '과 '... '입니다. 문자열이 아닌 객체가 어느 변수에라도 지정되면, 인터프리터가 새 대화식 명령을 읽을 준비를 할 때마다 그 객체의 str()이 재평가됩니다; 동적 프롬프트를 구현하는 데 사용할 수 있습니다.

sys.setdlopenflags(n)

Set the flags used by the interpreter for dlopen() calls, such as when the interpreter loads extension modules. Among other things, this will enable a lazy resolving of symbols when importing a module, if called as sys.setdlopenflags(0). To share symbols across extension modules, call as sys.setdlopenflags(os.RTLD_GLOBAL). Symbolic names for the flag values can be found in the os module (RTLD_xxx constants, e.g. os.RTLD_LAZY).

Availability: Unix.

sys.set_int_max_str_digits(maxdigits)

Set the integer string conversion length limitation used by this interpreter. See also get_int_max_str_digits().

Added in version 3.11.

sys.setprofile(profilefunc)

시스템의 프로파일 함수를 설정합니다. 파이썬에서 파이썬 소스 코드 프로파일러를 구현할 수 있도록 합니다. 파이썬 프로파일러에 대한 자세한 내용은 파이썬 프로파일러 장을 참조하십시오. 시스템의 프로파일 함수는 시스템의 추적 함수(settrace()를 참조하십시오)와 유사하게 호출되지만, 다른 이벤트로 호출됩니다, 예를 들어 이 함수는 실행되는 줄마다 호출되지 않습니다 (오직 호출과 반환에서만 호출됩니다만, 예외가 설정되었을 때도 반환 이벤트가 보고됩니다). 이 함수는 스레드로 한정되지만, 프로파일러가 스레드 간의 컨텍스트 전환에 대해 알 방법이 없어서, 여러 스레드가 있을 때 이를 사용하는 것은 의미가 없습니다. 또한, 반환 값이 사용되지 않아서, 단순히 None을 반환할 수 있습니다. 프로파일 함수에서 에러가 발생하면 설정이 해제됩니다.

참고

The same tracing mechanism is used for setprofile() as settrace(). To trace calls with setprofile() inside a tracing function (e.g. in a debugger breakpoint), see call_tracing().

프로파일 함수에는 세 가지 인자가 있습니다: frame, event 및 arg. frame은 현재 스택 프레임입니다. event는 문자열입니다: 'call', 'return', 'c_call', 'c_return' 또는 'c_exception'. arg는 이벤트 유형에 따라 다릅니다.

이벤트의 의미는 다음과 같습니다:

'call'

함수가 호출되었습니다 (또는 다른 코드 블록에 진입했습니다). 프로파일 함수가 호출됩니다; arg는 None입니다.

'return'

함수(또는 다른 코드 블록)가 반환하려고 합니다. 프로파일 함수가 호출됩니다; arg는 반환될 값이거나, 예외가 발생하여 이벤트가 발생한 경우는 None입니다.

'c_call'

C 함수를 호출하려고 합니다. 확장 함수나 내장일 수 있습니다. arg는 C 함수 객체입니다.

'c_return'

C 함수가 반환했습니다. arg는 C 함수 객체입니다.

'c_exception'

C 함수에서 예외가 발생했습니다. arg는 C 함수 객체입니다.

인자 없이 감사 이벤트 sys.setprofile을 발생시킵니다.

sys.setrecursionlimit(limit)

파이썬 인터프리터 스택의 최대 깊이를 limit로 설정합니다. 이 제한은 무한 재귀로 인해 C 스택의 오버플로가 발생하고 파이썬이 충돌하는 것을 방지합니다.

가능한 최대 제한은 플랫폼에 따라 다릅니다. 사용자는 깊은 재귀가 필요한 프로그램과 더 높은 제한을 지원하는 플랫폼이 있을 때 제한을 더 높게 설정해야 할 수 있습니다. 제한이 너무 높으면 충돌이 발생할 수 있기 때문에, 주의해서 사용해야 합니다.

현재 재귀 깊이에서 새 제한이 너무 낮으면 RecursionError 예외가 발생합니다.

버전 3.5.1에서 변경: 현재 재귀 깊이에서 새 한계가 너무 낮으면 이제 RecursionError 예외가 발생합니다.

sys.setswitchinterval(interval)

인터프리터의 스레드 전환 간격을 (초 단위로) 설정합니다. 이 부동 소수점 값은 동시에 실행 중인 파이썬 스레드에 할당된 “시 분할(timeslices)”의 이상적인 지속 시간을 결정합니다. 특히 오래 실행되는 내부 함수나 메서드가 사용된다면, 실제 값은 더 클 수 있음에 유의하십시오. 또한, 간격이 끝날 때 어떤 스레드가 예약되는지는 운영 체제의 결정입니다. 인터프리터에는 자체 스케줄러가 없습니다.

Added in version 3.2.

sys.settrace(tracefunc)

시스템의 추적 함수를 설정합니다. 파이썬에서 파이썬 소스 코드 디버거를 구현할 수 있도록 합니다. 이 함수는 스레드로 한정됩니다; 디버거가 여러 스레드를 지원하려면, 디버깅 중인 각 스레드에 대해 settrace()를 사용하여 추적 함수를 등록하거나, threading.settrace()를 사용해야 합니다.

추적 함수에는 세 개의 인자가 있습니다: frame, event 및 arg. frame은 현재 스택 프레임입니다. event는 문자열입니다: 'call', 'line', 'return', 'exception' 또는 'opcode'. arg는 이벤트 유형에 따라 다릅니다.

추적 함수는 새로운 로컬 스코프에 진입할 때마다 호출됩니다 (event가 'call'로 설정됩니다); 새 스코프에서 사용될 지역 추적 함수(local trace function)에 대한 참조를 반환하거나, 스코프를 추적하지 않아야 하면 None을 반환해야 합니다.

The local trace function should return a reference to itself, or to another function which would then be used as the local trace function for the scope.

추적 함수에서 에러가 발생하면, settrace(None)이 호출되는 것처럼 설정이 해제됩니다.

참고

Tracing is disabled while calling the trace function (e.g. a function set by settrace()). For recursive tracing see call_tracing().

이벤트의 의미는 다음과 같습니다:

'call'

함수가 호출되었습니다 (또는 다른 코드 블록에 진입했습니다). 전역 추적 함수가 호출됩니다; arg는 None입니다; 반환 값은 지역 추적 함수를 지정합니다.

'line'

The interpreter is about to execute a new line of code or re-execute the condition of a loop. The local trace function is called; arg is None; the return value specifies the new local trace function. See Objects/lnotab_notes.txt for a detailed explanation of how this works. Per-line events may be disabled for a frame by setting f_trace_lines to False on that frame.

'return'

함수(또는 다른 코드 블록)가 반환하려고 합니다. 지역 추적 함수가 호출됩니다; arg는 반환될 값이거나, 예외가 발생하여 이벤트가 발생한 경우는 None입니다. 추적 함수의 반환 값은 무시됩니다.

'exception'

예외가 발생했습니다. 지역 추적 함수가 호출됩니다; arg는 튜플 (exception, value, traceback)입니다; 반환 값은 새로운 지역 추적 함수를 지정합니다.

'opcode'

The interpreter is about to execute a new opcode (see dis for opcode details). The local trace function is called; arg is None; the return value specifies the new local trace function. Per-opcode events are not emitted by default: they must be explicitly requested by setting f_trace_opcodes to True on the frame.

호출자 체인을 따라 예외가 전파됨에 따라, 각 수준에서 'exception' 이벤트가 생성됨에 유의하십시오.

더 세분된 사용을 위해, 이미 설치된 추적 함수의 반환 값을 통해 간접적으로 설정되는 것에 의존하는 대신, frame.f_trace = tracefunc를 명시적으로 대입하여 추적 함수를 설정할 수 있습니다. 이것은 현재 프레임에서 추적 함수를 활성화하는 데에도 필요한데, settrace()가 하지 않는 일입니다. 이것이 작동하려면 실행 시간 추적 장치를 활성화하기 위해 전역 추적 함수가 settrace()로 설치되어 있어야 하지만, 같은 추적 함수 일 필요는 없음에 유의하십시오 (예를 들어, 각 프레임에서 즉시 비활성화되도록 단순히 None을 반환하는 오버헤드가 낮은 추적 함수일 수 있습니다).

코드와 프레임 객체에 대한 자세한 내용은 표준형 계층를 참조하십시오.

인자 없이 감사 이벤트 sys.settrace를 발생시킵니다.

CPython 구현 상세: settrace() 함수는 오직 디버거, 프로파일러, 커버리지(coverage) 도구 등을 구현하기 위한 것입니다. 그 동작은 언어 정의의 일부라기보다는 구현 플랫폼의 일부라서, 모든 파이썬 구현에서 사용 가능한 것은 아닙니다.

버전 3.7에서 변경: 'opcode' event type added; f_trace_lines and f_trace_opcodes attributes added to frames

sys.set_asyncgen_hooks([firstiter] [, finalizer])

두 개의 선택적 키워드 인자를 받아들이는데, 모두 비동기 제너레이터 이터레이터를 인자로 받아들이는 콜러블입니다. 비동기 제너레이터가 처음으로 이터레이트 될 때 firstiter 콜러블이 호출됩니다. 비동기 제너레이터가 가비지 수거될 때 finalizer가 호출됩니다.

인자 없이 감사 이벤트 sys.set_asyncgen_hooks_firstiter를 발생시킵니다.

인자 없이 감사 이벤트 sys.set_asyncgen_hooks_finalizer를 발생시킵니다.

하부 API는 두 개의 호출로 구성되기 때문에, 두 개의 감사 이벤트가 발생합니다, 각각은 자체 이벤트를 발생시켜야 합니다.

Added in version 3.6: 자세한 내용은 PEP 525 [https://peps.python.org/pep-0525/]를 참조하고, finalizer 메서드의 참조 예제는 Lib/asyncio/base_events.py [https://github.com/python/cpython/tree/main/Lib/asyncio/base_events.py]의 asyncio.Loop.shutdown_asyncgens 구현을 참조하십시오.

참고

이 함수는 잠정적(provisional)으로 추가되었습니다 (자세한 내용은 PEP 411 [https://peps.python.org/pep-0411/]을 참조하십시오).

sys.set_coroutine_origin_tracking_depth(depth)

Allows enabling or disabling coroutine origin tracking. When enabled, the cr_origin attribute on coroutine objects will contain a tuple of (filename, line number, function name) tuples describing the traceback where the coroutine object was created, with the most recent call first. When disabled, cr_origin will be None.

To enable, pass a depth value greater than zero; this sets the number of frames whose information will be captured. To disable, set depth to zero.

이 설정은 스레드에 한정됩니다.

Added in version 3.7.

참고

이 함수는 잠정적(provisional)으로 추가되었습니다 (자세한 내용은 PEP 411 [https://peps.python.org/pep-0411/]을 참조하십시오). 디버깅 목적으로만 사용하십시오.

sys.activate_stack_trampoline(backend, /)

Activate the stack profiler trampoline backend. The only supported backend is "perf".

Stack trampolines cannot be activated if the JIT is active.

Availability: Linux.

Added in version 3.12.

더 보기

Python support for the Linux perf profiler

https://perf.wiki.kernel.org

sys.deactivate_stack_trampoline()

Deactivate the current stack profiler trampoline backend.

If no stack profiler is activated, this function has no effect.

Availability: Linux.

Added in version 3.12.

sys.is_stack_trampoline_active()

Return True if a stack profiler trampoline is active.

Availability: Linux.

Added in version 3.12.

sys._enablelegacywindowsfsencoding()

Changes the filesystem encoding and error handler to ‘mbcs’ and ‘replace’ respectively, for consistency with versions of Python prior to 3.6.

이것은 파이썬을 시작하기 전에 PYTHONLEGACYWINDOWSFSENCODING 환경 변수를 정의하는 것과 동등합니다.

See also sys.getfilesystemencoding() and sys.getfilesystemencodeerrors().

Availability: Windows.

참고

Changing the filesystem encoding after Python startup is risky because the old fsencoding or paths encoded by the old fsencoding may be cached somewhere. Use PYTHONLEGACYWINDOWSFSENCODING instead.

Added in version 3.6: 자세한 내용은 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오.

Deprecated since version 3.13, will be removed in version 3.16: Use PYTHONLEGACYWINDOWSFSENCODING instead.

sys.stdin

sys.stdout

sys.stderr

인터프리터가 표준 입력, 출력 및 에러에 사용하는 파일 객체:

stdin는 모든 대화식 입력에 사용됩니다 (input() 호출을 포함합니다);

stdout은 print()와 표현식 문장의 출력과 input()의 프롬프트에 사용됩니다;

인터프리터 자신의 프롬프트와 에러 메시지는 stderr로 갑니다.

이 스트림은 open() 함수에 의해 반환되는 것과 같은 일반적인 텍스트 파일입니다. 매개 변수는 다음과 같이 선택됩니다:

The encoding and error handling are is initialized from PyConfig.stdio_encoding and PyConfig.stdio_errors.

On Windows, UTF-8 is used for the console device. Non-character devices such as disk files and pipes use the system locale encoding (i.e. the ANSI codepage). Non-console character devices such as NUL (i.e. where isatty() returns True) use the value of the console input and output codepages at startup, respectively for stdin and stdout/stderr. This defaults to the system locale encoding if the process is not initially attached to a console.

파이썬을 시작하기 전에 환경 변수 PYTHONLEGACYWINDOWSSTDIO를 설정하여 콘솔의 특수 동작을 재정의할 수 있습니다. 이 경우, 콘솔 코드 페이지는 다른 모든 문자 장치에서처럼 사용됩니다.

모든 플랫폼에서, 파이썬을 시작하기 전에 PYTHONIOENCODING 환경 변수를 설정하거나 새로운 -X utf8 명령 줄 옵션과 PYTHONUTF8 환경 변수를 사용하여 문자 인코딩을 재정의할 수 있습니다. 그러나, 윈도우 콘솔의 경우, PYTHONLEGACYWINDOWSSTDIO 도 설정했을 때만 적용됩니다.

대화형일 때, stdout 스트림은 줄 버퍼링 됩니다. 그렇지 않으면, 일반 텍스트 파일처럼 블록 버퍼링 됩니다. stderr 스트림은 두 경우 모두 줄 버퍼링 됩니다. -u 명령 줄 옵션을 전달하거나 PYTHONUNBUFFERED 환경 변수를 설정하여 두 스트림을 모두 버퍼링하지 않을 수 있습니다.

버전 3.9에서 변경: 비 대화형 stderr은 이제 완전히 버퍼링 되는 대신 줄 버퍼링 됩니다.

참고

표준 스트림에서 바이너리 데이터를 읽거나 표준 스트림으로 바이너리 데이터를 쓰려면, 하부 바이너리 buffer 객체를 사용하십시오. 예를 들어, 바이트열을 stdout에 쓰려면, sys.stdout.buffer.write(b'abc')를 사용하십시오.

However, if you are writing a library (and do not control in which context its code will be executed), be aware that the standard streams may be replaced with file-like objects like io.StringIO which do not support the buffer attribute.

sys.__stdin__

sys.__stdout__

sys.__stderr__

이 객체는 프로그램 시작 시 stdin, stderr 및 stdout의 원래 값을 포함합니다. 이들은 파이널리제이션 중에 사용되며, sys.std* 객체가 리디렉션 되었는지에 관계없이 실제 표준 스트림으로 인쇄하는 데 유용할 수 있습니다.

또한 잘못된 객체로 덮어쓴 경우 실제 파일을 알려진 작동하는 파일 객체로 복원하는 데 사용할 수 있습니다. 그러나, 이를 수행하기 위해 선호되는 방법은 이전 스트림을 교체하기 전에 명시적으로 저장하고, 저장된 객체를 복원하는 것입니다.

참고

일부 조건에서, stdin, stdout 및 stderr 뿐만 아니라 원래 값 __stdin__, __stdout__ 및 __stderr__은 None일 수 있습니다. 보통 콘솔에 연결되지 않은 윈도우 GUI 앱과 pythonw로 시작된 파이썬 앱이 이런 경우입니다.

sys.stdlib_module_names

A frozenset of strings containing the names of standard library modules.

It is the same on all platforms. Modules which are not available on some platforms and modules disabled at Python build are also listed. All module kinds are listed: pure Python, built-in, frozen and extension modules. Test modules are excluded.

For packages, only the main package is listed: sub-packages and sub-modules are not listed. For example, the email package is listed, but the email.mime sub-package and the email.message sub-module are not listed.

See also the sys.builtin_module_names list.

Added in version 3.10.

sys.thread_info

스레드 구현에 대한 정보를 담은 네임드 튜플.

thread_info.name

The name of the thread implementation:

"nt": Windows threads

"pthread": POSIX threads

"pthread-stubs": stub POSIX threads (on WebAssembly platforms without threading support)

"solaris": Solaris threads

thread_info.lock

The name of the lock implementation:

"semaphore": a lock uses a semaphore

"mutex+cond": a lock uses a mutex and a condition variable

이 정보를 알 수 없으면 None

thread_info.version

The name and version of the thread library. It is a string, or None if this information is unknown.

Added in version 3.3.

sys.tracebacklimit

이 변수가 정숫값으로 설정되면, 처리되지 않은 예외가 발생할 때 인쇄되는 트레이스백 정보의 최대 수준 수를 결정합니다. 기본값은 1000입니다. 0 이하로 설정하면, 모든 트레이스백 정보가 억제되고 예외 형과 값만 인쇄됩니다.

sys.unraisablehook(unraisable, /)

발생시킬 수 없는 예외(unraisable exception)를 처리합니다.

예외가 발생했지만, 파이썬이 예외를 처리할 방법이 없을 때 호출됩니다. 예를 들어, 파괴자가 예외를 발생시키거나 가비지 수거 (gc.collect()) 중에.

unraisable 인자에는 다음과 같은 어트리뷰트가 있습니다:

exc_type: Exception type.

exc_value: Exception value, can be None.

exc_traceback: Exception traceback, can be None.

err_msg: Error message, can be None.

object: Object causing the exception, can be None.

The default hook formats err_msg and object as: f'{err_msg}: {object!r}'; use “Exception ignored in” error message if err_msg is None.

sys.unraisablehook() 은 발생시킬 수 없는 예외 처리 방법을 제어하기 위해 재정의될 수 있습니다.

더 보기

excepthook() which handles uncaught exceptions.

경고

Storing exc_value using a custom hook can create a reference cycle. It should be cleared explicitly to break the reference cycle when the exception is no longer needed.

Storing object using a custom hook can resurrect it if it is set to an object which is being finalized. Avoid storing object after the custom hook completes to avoid resurrecting objects.

Raise an auditing event sys.unraisablehook with arguments hook, unraisable when an exception that cannot be handled occurs. The unraisable object is the same as what will be passed to the hook. If no hook has been set, hook may be None.

Added in version 3.8.

sys.version

파이썬 인터프리터의 버전 번호와 빌드 번호 및 사용된 컴파일러에 대한 추가 정보가 포함된 문자열. 이 문자열은 대화식 인터프리터가 시작될 때 표시됩니다. 여기서 버전 정보를 추출하지 말고, version_info와 platform 모듈이 제공하는 함수를 사용하십시오.

sys.api_version

이 인터프리터의 C API 버전. 프로그래머는 파이썬과 확장 모듈 간의 버전 충돌을 디버깅할 때 이것이 유용할 수 있습니다.

sys.version_info

버전 번호의 5가지 구성 요소를 포함하는 튜플: major, minor, micro, releaselevel 및 serial. releaselevel을 제외한 모든 값은 정수입니다; 릴리스 수준은 'alpha', 'beta', 'candidate' 또는 'final'입니다. 파이썬 버전 2.0에 해당하는 version_info 값은 (2, 0, 0, 'final', 0)입니다. 구성 요소는 이름으로도 액세스 할 수 있어서, sys.version_info[0]는 sys.version_info.major와 동등합니다.

버전 3.1에서 변경: 이름있는 구성 요소 어트리뷰트를 추가했습니다.

sys.warnoptions

이것은 경고 프레임워크의 구현 세부 사항입니다; 이 값을 수정하지 마십시오. 경고 프레임워크에 대한 자세한 정보는 warnings 모듈을 참조하십시오.

sys.winver

The version number used to form registry keys on Windows platforms. This is stored as string resource 1000 in the Python DLL. The value is normally the major and minor versions of the running Python interpreter. It is provided in the sys module for informational purposes; modifying this value has no effect on the registry keys used by Python.

Availability: Windows.

sys.monitoring

Namespace containing functions and constants for register callbacks and controlling monitoring events. See sys.monitoring for details.

sys._xoptions

-X 명령 줄 옵션을 통해 전달된 다양한 구현 특정 플래그의 딕셔너리. 옵션 이름은 명시적으로 지정되면 그들의 값으로, 그렇지 않으면 True로 매핑됩니다. 예:

$ ./python -Xa=b -Xc
Python 3.2a3+ (py3k, Oct 16 2010, 20:14:50)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys._xoptions
{'a': 'b', 'c': True}

CPython 구현 상세: 이는 -X를 통해 전달된 옵션에 액세스하는 CPython 특정 방법입니다. 다른 구현은 다른 수단을 통해, 또는 전혀 노출하지 않을 수 있습니다.

Added in version 3.2.

인용

[C99]

ISO/IEC 9899:1999. “Programming languages – C.” A public draft of this standard is available at https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf.

sys.monitoring — Execution event monitoring

Added in version 3.12.

참고

sys.monitoring is a namespace within the sys module, not an independent module, so there is no need to import sys.monitoring, simply import sys and then use sys.monitoring.

This namespace provides access to the functions and constants necessary to activate and control event monitoring.

As programs execute, events occur that might be of interest to tools that monitor execution. The sys.monitoring namespace provides means to receive callbacks when events of interest occur.

The monitoring API consists of three components:

Tool identifiers

Events

Callbacks

Tool identifiers

A tool identifier is an integer and the associated name. Tool identifiers are used to discourage tools from interfering with each other and to allow multiple tools to operate at the same time. Currently tools are completely independent and cannot be used to monitor each other. This restriction may be lifted in the future.

Before registering or activating events, a tool should choose an identifier. Identifiers are integers in the range 0 to 5 inclusive.

Registering and using tools

sys.monitoring.use_tool_id(tool_id: int, name: str, /) → None

Must be called before tool_id can be used. tool_id must be in the range 0 to 5 inclusive. Raises a ValueError if tool_id is in use.

sys.monitoring.clear_tool_id(tool_id: int, /) → None

Unregister all events and callback functions associated with tool_id.

sys.monitoring.free_tool_id(tool_id: int, /) → None

Should be called once a tool no longer requires tool_id. Will call clear_tool_id() before releasing tool_id.

sys.monitoring.get_tool(tool_id: int, /) → str | None

Returns the name of the tool if tool_id is in use, otherwise it returns None. tool_id must be in the range 0 to 5 inclusive.

All IDs are treated the same by the VM with regard to events, but the following IDs are pre-defined to make co-operation of tools easier:

sys.monitoring.DEBUGGER_ID = 0
sys.monitoring.COVERAGE_ID = 1
sys.monitoring.PROFILER_ID = 2
sys.monitoring.OPTIMIZER_ID = 5

Events

The following events are supported:

sys.monitoring.events.BRANCH

A conditional branch is taken (or not).

sys.monitoring.events.CALL

A call in Python code (event occurs before the call).

sys.monitoring.events.C_RAISE

An exception raised from any callable, except for Python functions (event occurs after the exit).

sys.monitoring.events.C_RETURN

Return from any callable, except for Python functions (event occurs after the return).

sys.monitoring.events.EXCEPTION_HANDLED

An exception is handled.

sys.monitoring.events.INSTRUCTION

A VM instruction is about to be executed.

sys.monitoring.events.JUMP

An unconditional jump in the control flow graph is made.

sys.monitoring.events.LINE

An instruction is about to be executed that has a different line number from the preceding instruction.

sys.monitoring.events.PY_RESUME

Resumption of a Python function (for generator and coroutine functions), except for throw() calls.

sys.monitoring.events.PY_RETURN

Return from a Python function (occurs immediately before the return, the callee’s frame will be on the stack).

sys.monitoring.events.PY_START

Start of a Python function (occurs immediately after the call, the callee’s frame will be on the stack)

sys.monitoring.events.PY_THROW

A Python function is resumed by a throw() call.

sys.monitoring.events.PY_UNWIND

Exit from a Python function during exception unwinding.

sys.monitoring.events.PY_YIELD

Yield from a Python function (occurs immediately before the yield, the callee’s frame will be on the stack).

sys.monitoring.events.RAISE

An exception is raised, except those that cause a STOP_ITERATION event.

sys.monitoring.events.RERAISE

An exception is re-raised, for example at the end of a finally block.

sys.monitoring.events.STOP_ITERATION

An artificial StopIteration is raised; see the STOP_ITERATION event.

More events may be added in the future.

These events are attributes of the sys.monitoring.events namespace. Each event is represented as a power-of-2 integer constant. To define a set of events, simply bitwise or the individual events together. For example, to specify both PY_RETURN and PY_START events, use the expression PY_RETURN | PY_START.

sys.monitoring.events.NO_EVENTS

An alias for 0 so users can do explicit comparisons like:

if get_events(DEBUGGER_ID) == NO_EVENTS:
    ...

Events are divided into three groups:

Local events

Local events are associated with normal execution of the program and happen at clearly defined locations. All local events can be disabled. The local events are:

PY_START

PY_RESUME

PY_RETURN

PY_YIELD

CALL

LINE

INSTRUCTION

JUMP

BRANCH

STOP_ITERATION

Ancillary events

Ancillary events can be monitored like other events, but are controlled by another event:

C_RAISE

C_RETURN

The C_RETURN and C_RAISE events are controlled by the CALL event. C_RETURN and C_RAISE events will only be seen if the corresponding CALL event is being monitored.

Other events

Other events are not necessarily tied to a specific location in the program and cannot be individually disabled.

The other events that can be monitored are:

PY_THROW

PY_UNWIND

RAISE

EXCEPTION_HANDLED

The STOP_ITERATION event

PEP 380 [https://peps.python.org/pep-0380/#use-of-stopiteration-to-return-values] specifies that a StopIteration exception is raised when returning a value from a generator or coroutine. However, this is a very inefficient way to return a value, so some Python implementations, notably CPython 3.12+, do not raise an exception unless it would be visible to other code.

To allow tools to monitor for real exceptions without slowing down generators and coroutines, the STOP_ITERATION event is provided. STOP_ITERATION can be locally disabled, unlike RAISE.

Note that the STOP_ITERATION event and the RAISE event for a StopIteration exception are equivalent, and are treated as interchangeable when generating events. Implementations will favor STOP_ITERATION for performance reasons, but may generate a RAISE event with a StopIteration.

Turning events on and off

In order to monitor an event, it must be turned on and a corresponding callback must be registered. Events can be turned on or off by setting the events either globally or for a particular code object.

Setting events globally

Events can be controlled globally by modifying the set of events being monitored.

sys.monitoring.get_events(tool_id: int, /) → int

Returns the int representing all the active events.

sys.monitoring.set_events(tool_id: int, event_set: int, /) → None

Activates all events which are set in event_set. Raises a ValueError if tool_id is not in use.

No events are active by default.

Per code object events

Events can also be controlled on a per code object basis. The functions defined below which accept a types.CodeType should be prepared to accept a look-alike object from functions which are not defined in Python (see Monitoring C API).

sys.monitoring.get_local_events(tool_id: int, code: CodeType, /) → int

Returns all the local events for code

sys.monitoring.set_local_events(tool_id: int, code: CodeType, event_set: int, /) → None

Activates all the local events for code which are set in event_set. Raises a ValueError if tool_id is not in use.

Local events add to global events, but do not mask them. In other words, all global events will trigger for a code object, regardless of the local events.

Disabling events

sys.monitoring.DISABLE

A special value that can be returned from a callback function to disable events for the current code location.

Local events can be disabled for a specific code location by returning sys.monitoring.DISABLE from a callback function. This does not change which events are set, or any other code locations for the same event.

Disabling events for specific locations is very important for high performance monitoring. For example, a program can be run under a debugger with no overhead if the debugger disables all monitoring except for a few breakpoints.

sys.monitoring.restart_events() → None

Enable all the events that were disabled by sys.monitoring.DISABLE for all tools.

Registering callback functions

To register a callable for events call

sys.monitoring.register_callback(tool_id: int, event: int, func: Callable | None, /) → Callable | None

Registers the callable func for the event with the given tool_id

If another callback was registered for the given tool_id and event, it is unregistered and returned. Otherwise register_callback() returns None.

Functions can be unregistered by calling sys.monitoring.register_callback(tool_id, event, None).

Callback functions can be registered and unregistered at any time.

Registering or unregistering a callback function will generate a sys.audit() event.

Callback function arguments

sys.monitoring.MISSING

A special value that is passed to a callback function to indicate that there are no arguments to the call.

When an active event occurs, the registered callback function is called. Different events will provide the callback function with different arguments, as follows:

PY_START and PY_RESUME:

func(code: CodeType, instruction_offset: int) -> DISABLE | Any

PY_RETURN and PY_YIELD:

func(code: CodeType, instruction_offset: int, retval: object) -> DISABLE | Any

CALL, C_RAISE and C_RETURN:

func(code: CodeType, instruction_offset: int, callable: object, arg0: object | MISSING) -> DISABLE | Any

If there are no arguments, arg0 is set to sys.monitoring.MISSING.

RAISE, RERAISE, EXCEPTION_HANDLED, PY_UNWIND, PY_THROW and STOP_ITERATION:

func(code: CodeType, instruction_offset: int, exception: BaseException) -> DISABLE | Any

LINE:

func(code: CodeType, line_number: int) -> DISABLE | Any

BRANCH and JUMP:

func(code: CodeType, instruction_offset: int, destination_offset: int) -> DISABLE | Any

Note that the destination_offset is where the code will next execute. For an untaken branch this will be the offset of the instruction following the branch.

INSTRUCTION:

func(code: CodeType, instruction_offset: int) -> DISABLE | Any

sysconfig — Provide access to Python’s configuration information

Added in version 3.2.

Source code: Lib/sysconfig [https://github.com/python/cpython/tree/main/Lib/sysconfig]

sysconfig 모듈은 설치 경로 목록과 현재 플랫폼과 관련된 구성 변수와 같은 파이썬 구성 정보에 대한 액세스를 제공합니다.

구성 변수

A Python distribution contains a Makefile and a pyconfig.h header file that are necessary to build both the Python binary itself and third-party C extensions compiled using setuptools.

sysconfig 는 get_config_vars() 또는 get_config_var()를 사용하여 액세스 할 수 있는 딕셔너리에 이들 파일에 있는 모든 변수를 넣습니다.

윈도우에서는 훨씬 작은 세트입니다.

sysconfig.get_config_vars(*args)

인자가 없으면, 현재 플랫폼과 관련된 모든 구성 변수의 딕셔너리를 반환합니다.

인자가 있으면, 인자를 사용하여 구성 변수 딕셔너리에서 각 인자를 조회한 결괏값 리스트를 돌려줍니다.

인자별로, 값이 없으면 None 을 반환합니다.

sysconfig.get_config_var(name)

하나의 변수 name 의 값을 반환합니다. get_config_vars().get(name) 과 같습니다.

name 을 찾지 못하면 None 을 반환합니다.

사용 예:

>>> import sysconfig
>>> sysconfig.get_config_var('Py_ENABLE_SHARED')
0
>>> sysconfig.get_config_var('LIBDIR')
'/usr/local/lib'
>>> sysconfig.get_config_vars('AR', 'CXX')
['ar', 'g++']

설치 경로

Python uses an installation scheme that differs depending on the platform and on the installation options. These schemes are stored in sysconfig under unique identifiers based on the value returned by os.name. The schemes are used by package installers to determine where to copy files to.

Python currently supports nine schemes:

posix_prefix: scheme for POSIX platforms like Linux or macOS. This is the default scheme used when Python or a component is installed.

posix_home: scheme for POSIX platforms, when the home option is used. This scheme defines paths located under a specific home prefix.

posix_user: scheme for POSIX platforms, when the user option is used. This scheme defines paths located under the user’s home directory (site.USER_BASE).

posix_venv: scheme for Python virtual environments on POSIX platforms; by default it is the same as posix_prefix.

nt: scheme for Windows. This is the default scheme used when Python or a component is installed.

nt_user: scheme for Windows, when the user option is used.

nt_venv: scheme for Python virtual environments on Windows; by default it is the same as nt.

venv: a scheme with values from either posix_venv or nt_venv depending on the platform Python runs on.

osx_framework_user: scheme for macOS, when the user option is used.

각 스킴은 일련의 경로로 구성되며 각 경로는 고유한 식별자를 가집니다. 파이썬은 현재 8개의 경로를 사용합니다:

stdlib: 플랫폼마다 다르지 않은 표준 파이썬 라이브러리 파일이 들어있는 디렉터리.

platstdlib: 플랫폼마다 다른 표준 파이썬 라이브러리 파일이 들어있는 디렉터리.

platlib: 사이트마다, 플랫폼마다 다른 파일용 디렉터리.

purelib: directory for site-specific, non-platform-specific files (‘pure’ Python).

include: directory for non-platform-specific header files for the Python C-API.

platinclude: directory for platform-specific header files for the Python C-API.

scripts: 스크립트 파일용 디렉터리.

data: 데이터 파일용 디렉터리.

User scheme

This scheme is designed to be the most convenient solution for users that don’t have write permission to the global site-packages directory or don’t want to install into it.

Files will be installed into subdirectories of site.USER_BASE (written as userbase hereafter). This scheme installs pure Python modules and extension modules in the same location (also known as site.USER_SITE).

posix_user

Path

Installation directory

stdlib

userbase/lib/pythonX.Y

platstdlib

userbase/lib/pythonX.Y

platlib

userbase/lib/pythonX.Y/site-packages

purelib

userbase/lib/pythonX.Y/site-packages

include

userbase/include/pythonX.Y

scripts

userbase/bin

data

userbase

nt_user

Path

Installation directory

stdlib

userbase\PythonXY

platstdlib

userbase\PythonXY

platlib

userbase\PythonXY\site-packages

purelib

userbase\PythonXY\site-packages

include

userbase\PythonXY\Include

scripts

userbase\PythonXY\Scripts

data

userbase

osx_framework_user

Path

Installation directory

stdlib

userbase/lib/python

platstdlib

userbase/lib/python

platlib

userbase/lib/python/site-packages

purelib

userbase/lib/python/site-packages

include

userbase/include/pythonX.Y

scripts

userbase/bin

data

userbase

Home scheme

The idea behind the “home scheme” is that you build and maintain a personal stash of Python modules. This scheme’s name is derived from the idea of a “home” directory on Unix, since it’s not unusual for a Unix user to make their home directory have a layout similar to /usr/ or /usr/local/. This scheme can be used by anyone, regardless of the operating system they are installing for.

posix_home

Path

Installation directory

stdlib

home/lib/python

platstdlib

home/lib/python

platlib

home/lib/python

purelib

home/lib/python

include

home/include/python

platinclude

home/include/python

scripts

home/bin

data

home

Prefix scheme

The “prefix scheme” is useful when you wish to use one Python installation to perform the build/install (i.e., to run the setup script), but install modules into the third-party module directory of a different Python installation (or something that looks like a different Python installation). If this sounds a trifle unusual, it is—that’s why the user and home schemes come before. However, there are at least two known cases where the prefix scheme will be useful.

First, consider that many Linux distributions put Python in /usr, rather than the more traditional /usr/local. This is entirely appropriate, since in those cases Python is part of “the system” rather than a local add-on. However, if you are installing Python modules from source, you probably want them to go in /usr/local/lib/python2.X rather than /usr/lib/python2.X.

Another possibility is a network filesystem where the name used to write to a remote directory is different from the name used to read it: for example, the Python interpreter accessed as /usr/local/bin/python might search for modules in /usr/local/lib/python2.X, but those modules would have to be installed to, say, /mnt/@server/export/lib/python2.X.

posix_prefix

Path

Installation directory

stdlib

prefix/lib/pythonX.Y

platstdlib

prefix/lib/pythonX.Y

platlib

prefix/lib/pythonX.Y/site-packages

purelib

prefix/lib/pythonX.Y/site-packages

include

prefix/include/pythonX.Y

platinclude

prefix/include/pythonX.Y

scripts

prefix/bin

data

prefix

nt

Path

Installation directory

stdlib

prefix\Lib

platstdlib

prefix\Lib

platlib

prefix\Lib\site-packages

purelib

prefix\Lib\site-packages

include

prefix\Include

platinclude

prefix\Include

scripts

prefix\Scripts

data

prefix

Installation path functions

sysconfig provides some functions to determine these installation paths.

sysconfig.get_scheme_names()

현재 sysconfig 에서 지원되는 모든 스킴을 포함하는 튜플을 돌려줍니다.

sysconfig.get_default_scheme()

Return the default scheme name for the current platform.

Added in version 3.10: This function was previously named _get_default_scheme() and considered an implementation detail.

버전 3.11에서 변경: When Python runs from a virtual environment, the venv scheme is returned.

sysconfig.get_preferred_scheme(key)

Return a preferred scheme name for an installation layout specified by key.

key must be either "prefix", "home", or "user".

The return value is a scheme name listed in get_scheme_names(). It can be passed to sysconfig functions that take a scheme argument, such as get_paths().

Added in version 3.10.

버전 3.11에서 변경: When Python runs from a virtual environment and key="prefix", the venv scheme is returned.

sysconfig._get_preferred_schemes()

Return a dict containing preferred scheme names on the current platform. Python implementers and redistributors may add their preferred schemes to the _INSTALL_SCHEMES module-level global value, and modify this function to return those scheme names, to e.g. provide different schemes for system and language package managers to use, so packages installed by either do not mix with those by the other.

End users should not use this function, but get_default_scheme() and get_preferred_scheme() instead.

Added in version 3.10.

sysconfig.get_path_names()

현재 sysconfig 에서 지원되는 모든 경로명을 포함하는 튜플을 돌려줍니다.

sysconfig.get_path(name[, scheme[, vars[, expand]]])

scheme 이라는 설치 스킴에서, 경로 name 에 해당하는 설치 경로를 돌려줍니다.

name 은 get_path_names() 가 돌려주는 리스트에 있는 값이어야 합니다.

sysconfig 는 각 경로명에 해당하는 설치 경로를 플랫폼별로 확장할 변수와 함께 저장합니다. 예를 들어, nt 스킴의 stdlib 경로는 {base}/Lib 입니다.

get_path() 는 get_config_vars() 에 의해 반환된 변수를 사용하여 경로를 확장합니다. 모든 변수는 각 플랫폼에 대한 기본값을 가지므로 이 함수를 호출하고 기본값을 가져올 수 있습니다.

scheme 이 제공되면, 그것은 get_scheme_names() 에 의해 반환된 리스트에 있는 값이어야 합니다. 그렇지 않으면, 현재 플랫폼의 기본 스킴이 사용됩니다.

If vars is provided, it must be a dictionary of variables that will update the dictionary returned by get_config_vars().

expand 가 False 로 설정되면, 경로는 변수를 사용하여 확장되지 않습니다.

If name is not found, raise a KeyError.

sysconfig.get_paths([scheme[, vars[, expand]]])

설치 스킴에 해당하는 모든 설치 경로를 포함하는 딕셔너리를 돌려줍니다. 자세한 정보는 get_path() 를 보십시오.

scheme 을 제공하지 않으면, 현재 플랫폼에 대한 기본 스킴을 사용합니다.

vars 가 제공되면, 경로를 확장하는 데 사용되는 딕셔너리를 갱신하는 변수의 딕셔너리여야 합니다.

expand 를 거짓으로 설정하면 경로가 확장되지 않습니다.

scheme 이 존재하는 스킴이 아니면, get_paths() 는 KeyError 를 발생시킵니다.

기타 함수

sysconfig.get_python_version()

MAJOR.MINOR 파이썬 버전 번호를 문자열로 반환합니다. '%d.%d' % sys.version_info[:2] 와 유사합니다.

sysconfig.get_platform()

현재의 플랫폼을 식별하는 문자열을 돌려줍니다.

This is used mainly to distinguish platform-specific build directories and platform-specific built distributions. Typically includes the OS name and version and the architecture (as supplied by os.uname()), although the exact information included depends on the OS; e.g., on Linux, the kernel version isn’t particularly important.

반환 값의 예:

linux-i586

linux-alpha (?)

solaris-2.6-sun4u

윈도우는 다음 중 하나를 반환합니다:

win-amd64 (AMD64의 64비트 윈도우, 일명 x86_64, Intel64, EM64T 등)

win32 (기타 모든 것 - 구체적으로, sys.platform이 반환됩니다)

macOS can return:

macosx-10.6-ppc

macosx-10.4-ppc64

macosx-10.3-i386

macosx-10.4-fat

다른 포직스 이외의 플랫폼의 경우, 현재는 sys.platform 만 반환합니다.

sysconfig.is_python_build()

실행 중인 파이썬 인터프리터가 소스에서 빌드되어 빌드 된 위치에서 실행되고, make install 을 실행하거나 바이너리 설치 프로그램을 통해 설치 한 결과가 아닌 위치에서 실행되는 것이 아니라면 True 를 반환합니다.

sysconfig.parse_config_h(fp[, vars])

config.h-스타일 파일을 해석합니다.

fp 는 config.h-류 파일을 가리키는 파일류 객체입니다.

이름/값 쌍을 포함하는 딕셔너리가 반환됩니다. 선택적 딕셔너리가 두 번째 인자로 전달되면, 새 사전 대신 사용되며 파일에서 읽은 값으로 갱신됩니다.

sysconfig.get_config_h_filename()

pyconfig.h 의 경로를 반환합니다.

sysconfig.get_makefile_filename()

Makefile 의 경로를 반환합니다.

sysconfig 를 스크립트로 사용하기

sysconfig 를 파이썬의 -m 옵션으로 스크립트로 사용할 수 있습니다:

$ python -m sysconfig
Platform: "macosx-10.4-i386"
Python version: "3.2"
Current installation scheme: "posix_prefix"

Paths:
        data = "/usr/local"
        include = "/Users/tarek/Dev/svn.python.org/py3k/Include"
        platinclude = "."
        platlib = "/usr/local/lib/python3.2/site-packages"
        platstdlib = "/usr/local/lib/python3.2"
        purelib = "/usr/local/lib/python3.2/site-packages"
        scripts = "/usr/local/bin"
        stdlib = "/usr/local/lib/python3.2"

Variables:
        AC_APPLE_UNIVERSAL_BUILD = "0"
        AIX_GENUINE_CPLUSPLUS = "0"
        AR = "ar"
        ARFLAGS = "rc"
        ...

이 호출은 get_platform(), get_python_version(), get_path() 및 get_config_vars() 에 의해 반환된 정보를 표준 출력에 인쇄합니다.

builtins — Built-in objects

This module provides direct access to all ‘built-in’ identifiers of Python; for example, builtins.open is the full name for the built-in function open().

이 모듈은 일반적으로 대부분의 응용 프로그램에서 명시적으로 액세스하지 않지만, 내장된 값과 이름이 같은 객체를 제공하면서도 그 이름의 내장 객체가 필요한 모듈에서 유용 할 수 있습니다. 예를 들어, 내장 open() 을 감싸는 open() 함수를 구현하고자 하는 모듈에서 이 모듈을 직접 사용할 수 있습니다:

import builtins

def open(path):
    f = builtins.open(path, 'r')
    return UpperCaser(f)

class UpperCaser:
    '''Wrapper around a file that converts output to uppercase.'''

    def __init__(self, f):
        self._f = f

    def read(self, count=-1):
        return self._f.read(count).upper()

    # ...

구현 세부 사항으로, 대부분 모듈은 전역 변수로 __builtins__ 라는 이름을 가지고 있습니다. __builtins__ 의 값은, 보통 이 모듈이거나 모듈의 __dict__ 어트리뷰트의 값입니다. 이것은 구현 세부 사항이므로, 파이썬의 대안 구현에서는 사용되지 않을 수 있습니다.

더 보기

내장 상수

내장 예외

내장 함수

내장형

__main__ — Top-level code environment

In Python, the special name __main__ is used for two important constructs:

the name of the top-level environment of the program, which can be checked using the __name__ == '__main__' expression; and

the __main__.py file in Python packages.

Both of these mechanisms are related to Python modules; how users interact with them and how they interact with each other. They are explained in detail below. If you’re new to Python modules, see the tutorial section 모듈 for an introduction.

__name__ == '__main__'

When a Python module or package is imported, __name__ is set to the module’s name. Usually, this is the name of the Python file itself without the .py extension:

>>> import configparser
>>> configparser.__name__
'configparser'

If the file is part of a package, __name__ will also include the parent package’s path:

>>> from concurrent.futures import process
>>> process.__name__
'concurrent.futures.process'

However, if the module is executed in the top-level code environment, its __name__ is set to the string '__main__'.

What is the “top-level code environment”?

__main__ is the name of the environment where top-level code is run. “Top-level code” is the first user-specified Python module that starts running. It’s “top-level” because it imports all other modules that the program needs. Sometimes “top-level code” is called an entry point to the application.

The top-level code environment can be:

the scope of an interactive prompt:

>>> __name__
'__main__'

the Python module passed to the Python interpreter as a file argument:

$ python helloworld.py
Hello, world!

the Python module or package passed to the Python interpreter with the -m argument:

$ python -m tarfile
usage: tarfile.py [-h] [-v] (...)

Python code read by the Python interpreter from standard input:

$ echo "import this" | python
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
...

Python code passed to the Python interpreter with the -c argument:

$ python -c "import this"
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
...

In each of these situations, the top-level module’s __name__ is set to '__main__'.

As a result, a module can discover whether or not it is running in the top-level environment by checking its own __name__, which allows a common idiom for conditionally executing code when the module is not initialized from an import statement:

if __name__ == '__main__':
    # Execute when the module is not initialized from an import statement.
    ...

더 보기

For a more detailed look at how __name__ is set in all situations, see the tutorial section 모듈.

Idiomatic Usage

Some modules contain code that is intended for script use only, like parsing command-line arguments or fetching data from standard input. If a module like this was imported from a different module, for example to unit test it, the script code would unintentionally execute as well.

This is where using the if __name__ == '__main__' code block comes in handy. Code within this block won’t run unless the module is executed in the top-level environment.

Putting as few statements as possible in the block below if __name__ == '__main__' can improve code clarity and correctness. Most often, a function named main encapsulates the program’s primary behavior:

# echo.py

import shlex
import sys

def echo(phrase: str) -> None:
   """A dummy wrapper around print."""
   # for demonstration purposes, you can imagine that there is some
   # valuable and reusable logic inside this function
   print(phrase)

def main() -> int:
    """Echo the input arguments to standard output"""
    phrase = shlex.join(sys.argv)
    echo(phrase)
    return 0

if __name__ == '__main__':
    sys.exit(main())  # next section explains the use of sys.exit

Note that if the module didn’t encapsulate code inside the main function but instead put it directly within the if __name__ == '__main__' block, the phrase variable would be global to the entire module. This is error-prone as other functions within the module could be unintentionally using the global variable instead of a local name. A main function solves this problem.

Using a main function has the added benefit of the echo function itself being isolated and importable elsewhere. When echo.py is imported, the echo and main functions will be defined, but neither of them will be called, because __name__ != '__main__'.

Packaging Considerations

main functions are often used to create command-line tools by specifying them as entry points for console scripts. When this is done, pip [https://pip.pypa.io/] inserts the function call into a template script, where the return value of main is passed into sys.exit(). For example:

sys.exit(main())

Since the call to main is wrapped in sys.exit(), the expectation is that your function will return some value acceptable as an input to sys.exit(); typically, an integer or None (which is implicitly returned if your function does not have a return statement).

By proactively following this convention ourselves, our module will have the same behavior when run directly (i.e. python echo.py) as it will have if we later package it as a console script entry-point in a pip-installable package.

In particular, be careful about returning strings from your main function. sys.exit() will interpret a string argument as a failure message, so your program will have an exit code of 1, indicating failure, and the string will be written to sys.stderr. The echo.py example from earlier exemplifies using the sys.exit(main()) convention.

더 보기

Python Packaging User Guide [https://packaging.python.org/] contains a collection of tutorials and references on how to distribute and install Python packages with modern tools.

__main__.py in Python Packages

If you are not familiar with Python packages, see section 패키지 of the tutorial. Most commonly, the __main__.py file is used to provide a command-line interface for a package. Consider the following hypothetical package, “bandclass”:

bandclass
  ├── __init__.py
  ├── __main__.py
  └── student.py

__main__.py will be executed when the package itself is invoked directly from the command line using the -m flag. For example:

$ python -m bandclass

This command will cause __main__.py to run. How you utilize this mechanism will depend on the nature of the package you are writing, but in this hypothetical case, it might make sense to allow the teacher to search for students:

# bandclass/__main__.py

import sys
from .student import search_students

student_name = sys.argv[1] if len(sys.argv) >= 2 else ''
print(f'Found student: {search_students(student_name)}')

Note that from .student import search_students is an example of a relative import. This import style can be used when referencing modules within a package. For more details, see 패키지 내부 간의 참조 in the 모듈 section of the tutorial.

Idiomatic Usage

The content of __main__.py typically isn’t fenced with an if __name__ == '__main__' block. Instead, those files are kept short and import functions to execute from other modules. Those other modules can then be easily unit-tested and are properly reusable.

If used, an if __name__ == '__main__' block will still work as expected for a __main__.py file within a package, because its __name__ attribute will include the package’s path if imported:

>>> import asyncio.__main__
>>> asyncio.__main__.__name__
'asyncio.__main__'

This won’t work for __main__.py files in the root directory of a .zip file though. Hence, for consistency, a minimal __main__.py without a __name__ check is preferred.

더 보기

See venv for an example of a package with a minimal __main__.py in the standard library. It doesn’t contain a if __name__ == '__main__' block. You can invoke it with python -m venv [directory].

See runpy for more details on the -m flag to the interpreter executable.

See zipapp for how to run applications packaged as .zip files. In this case Python looks for a __main__.py file in the root directory of the archive.

import __main__

Regardless of which module a Python program was started with, other modules running within that same program can import the top-level environment’s scope (namespace) by importing the __main__ module. This doesn’t import a __main__.py file but rather whichever module that received the special name '__main__'.

Here is an example module that consumes the __main__ namespace:

# namely.py

import __main__

def did_user_define_their_name():
    return 'my_name' in dir(__main__)

def print_user_name():
    if not did_user_define_their_name():
        raise ValueError('Define the variable `my_name`!')

    if '__file__' in dir(__main__):
        print(__main__.my_name, "found in file", __main__.__file__)
    else:
        print(__main__.my_name)

Example usage of this module could be as follows:

# start.py

import sys

from namely import print_user_name

# my_name = "Dinsdale"

def main():
    try:
        print_user_name()
    except ValueError as ve:
        return str(ve)

if __name__ == "__main__":
    sys.exit(main())

Now, if we started our program, the result would look like this:

$ python start.py
Define the variable `my_name`!

The exit code of the program would be 1, indicating an error. Uncommenting the line with my_name = "Dinsdale" fixes the program and now it exits with status code 0, indicating success:

$ python start.py
Dinsdale found in file /path/to/start.py

Note that importing __main__ doesn’t cause any issues with unintentionally running top-level code meant for script use which is put in the if __name__ == "__main__" block of the start module. Why does this work?

Python inserts an empty __main__ module in sys.modules at interpreter startup, and populates it by running top-level code. In our example this is the start module which runs line by line and imports namely. In turn, namely imports __main__ (which is really start). That’s an import cycle! Fortunately, since the partially populated __main__ module is present in sys.modules, Python passes that to namely. See Special considerations for __main__ in the import system’s reference for details on how this works.

The Python REPL is another example of a “top-level environment”, so anything defined in the REPL becomes part of the __main__ scope:

>>> import namely
>>> namely.did_user_define_their_name()
False
>>> namely.print_user_name()
Traceback (most recent call last):
...
ValueError: Define the variable `my_name`!
>>> my_name = 'Jabberwocky'
>>> namely.did_user_define_their_name()
True
>>> namely.print_user_name()
Jabberwocky

Note that in this case the __main__ scope doesn’t contain a __file__ attribute as it’s interactive.

The __main__ scope is used in the implementation of pdb and rlcompleter.

warnings — Warning control

소스 코드: Lib/warnings.py [https://github.com/python/cpython/tree/main/Lib/warnings.py]

경고 메시지는 일반적으로 프로그램에서 사용자에게 (일반적으로) 예외를 발생시키거나 프로그램을 종료하는 것을 보증하지 않는 특정 조건에 대해 경고하는 것이 유용한 상황 상황에서 발행됩니다. 예를 들어, 프로그램이 더는 사용되지 않는 모듈을 사용할 때 경고를 발행하려고 할 수 있습니다.

파이썬 프로그래머는 이 모듈에 정의된 warn() 함수를 호출하여 경고를 발행합니다. (C 프로그래머는 PyErr_WarnEx()를 사용합니다; 자세한 내용은 예외 처리를 참조하십시오).

경고 메시지는 일반적으로 sys.stderr에 기록되지만, 모든 경고를 무시하는 것에서 예외로 변경하는 것에 이르기까지 배치를 유연하게 변경할 수 있습니다. 경고의 처리는 경고 범주, 경고 메시지의 텍스트 및 발행된 소스 위치에 따라 달라질 수 있습니다. 같은 소스 위치에 대한 특정 경고의 반복은 일반적으로 억제됩니다.

경고 제어에는 두 가지 단계가 있습니다; 첫째, 경고가 발행될 때마다, 메시지를 발행할지를 결정합니다; 다음으로, 메시지가 발행된다면, 사용자 설정 가능한 훅을 사용하여 포맷되고 인쇄됩니다.

경고 메시지를 발행할지는 경고 필터에 의해 제어되며, 이는 일치 규칙과 조치의 시퀀스입니다. filterwarnings()를 호출하여 규칙을 필터에 추가하고 resetwarnings()를 호출하여 기본 상태로 재설정할 수 있습니다.

경고 메시지의 인쇄는 showwarning()을 호출하여 수행되며, 이는 재정의될 수 있습니다; 이 함수의 기본 구현은 formatwarning()을 호출하여 메시지를 포맷하며, 사용자 정의 구현에서도 사용할 수 있습니다.

더 보기

logging.captureWarnings()를 사용하면 표준 로깅 인프라로 모든 경고를 처리할 수 있습니다.

경고 범주

경고 범주를 나타내는 여러 가지 내장 예외가 있습니다. 이 범주화는 경고 그룹을 필터링하는 데 유용합니다.

이들은 기술적으로 내장 예외이지만, 개념적으로 경고 메커니즘에 속하기 때문에 여기에서 설명합니다.

사용자 코드는 표준 경고 범주 중 하나를 서브 클래싱 하여 추가 경고 범주를 정의할 수 있습니다. 경고 범주는 항상 Warning 클래스의 서브 클래스여야 합니다.

다음과 같은 경고 범주 클래스가 현재 정의되어 있습니다:

클래스

설명

Warning

이것은 모든 경고 범주 클래스의 베이스 클래스입니다. Exception의 서브 클래스입니다.

UserWarning

warn()의 기본 범주.

DeprecationWarning

폐지된 기능에 대한 경고의 베이스 범주, 경고가 다른 파이썬 개발자를 대상으로 할 때 (__main__에 있는 코드로 트리거 되지 않는 한 기본적으로 무시됩니다).

SyntaxWarning

모호한 구문 기능에 대한 경고의 베이스 범주.

RuntimeWarning

모호한 런타임 기능에 대한 경고의 베이스 범주.

FutureWarning

폐지된 기능에 대한 경고의 베이스 범주, 경고가 파이썬으로 작성된 응용 프로그램의 최종 사용자를 대상으로 할 때.

PendingDeprecationWarning

향후 폐지될 기능에 대한 경고의 베이스 범주 (기본적으로 무시됩니다).

ImportWarning

모듈을 임포트 하는 과정에서 트리거 되는 경고의 베이스 범주 (기본적으로 무시됩니다).

UnicodeWarning

유니코드와 관련된 경고의 베이스 범주.

BytesWarning

bytes와 bytearray와 관련된 경고의 베이스 범주.

ResourceWarning

Base category for warnings related to resource usage (ignored by default).

버전 3.7에서 변경: 이전에는 DeprecationWarning과 FutureWarning은 기능이 완전히 제거되었는지 또는 동작을 변경하는지에 따라 구별되었습니다. 이제 의도한 대상과 기본 경고 필터에서 처리하는 방식에 따라 구별됩니다.

경고 필터

경고 필터는 경고를 무시, 표시 또는 에러로 전환(예외 발생)할지를 제어합니다.

개념적으로, 경고 필터는 필터 명세의 순서 있는 목록을 유지합니다; 일치가 발견될 때까지 목록의 각 필터 명세에 대해 특정 경고를 일치시킵니다; 필터는 일치의 처리를 결정합니다. 각 항목은 (action, message, category, module, lineno) 형식의 튜플입니다, 여기서:

action은 다음 문자열 중 하나입니다:

값

처리

"default"

경고가 발행된 각 위치(모듈 + 줄 번호)에 대해 일치하는 경고의 첫 번째 발생을 인쇄합니다

"error"

일치하는 경고를 예외로 바꿉니다

"ignore"

일치하는 경고를 인쇄하지 않습니다

"always"

일치하는 경고를 항상 인쇄합니다

"all"

alias to “always”

"module"

경고가 발행된 모듈마다 (줄 번호와 관계없이) 일치하는 경고의 첫 번째 발생을 인쇄합니다

"once"

위치와 관계없이 일치하는 경고의 첫 번째 발생만 인쇄합니다

message is a string containing a regular expression that the start of the warning message must match, case-insensitively. In -W and PYTHONWARNINGS, message is a literal string that the start of the warning message must contain (case-insensitively), ignoring any whitespace at the start or end of message.

category는 클래스(Warning의 서브 클래스)이며, 일치하는 경고 범주는 이것의 서브 클래스여야 합니다.

module is a string containing a regular expression that the start of the fully qualified module name must match, case-sensitively. In -W and PYTHONWARNINGS, module is a literal string that the fully qualified module name must be equal to (case-sensitively), ignoring any whitespace at the start or end of module.

lineno는 경고가 발생한 줄 번호가 일치해야 하는 정수이거나, 모든 줄 번호와 일치하려면 0입니다.

Warning 클래스는 내장 Exception 클래스에서 파생되므로, 경고를 에러로 바꾸려면 단순히 category(message)를 raise 합니다.

경고가 보고되고 등록된 필터와 일치하지 않으면 “default” 조치가 적용됩니다 (그래서 그런 이름을 갖고 있습니다).

Repeated Warning Suppression Criteria

The filters that suppress repeated warnings apply the following criteria to determine if a warning is considered a repeat:

"default": A warning is considered a repeat only if the (message, category, module, lineno) are all the same.

"module": A warning is considered a repeat if the (message, category, module) are the same, ignoring the line number.

"once": A warning is considered a repeat if the (message, category) are the same, ignoring the module and line number.

경고 필터 설명

경고 필터는 파이썬 인터프리터 명령 줄로 전달된 -W 옵션과 PYTHONWARNINGS 환경 변수로 초기화됩니다. 인터프리터는 sys.warnoptions에서 제공된 모든 항목에 대한 인자를 해석하지 않고 저장합니다; warnings 모듈은 처음 임포트 될 때 이를 구문 분석합니다 (유효하지 않은 옵션은 메시지를 sys.stderr에 인쇄한 후 무시됩니다).

개별 경고 필터는 콜론으로 구분된 필드의 시퀀스로 지정됩니다:

action:message:category:module:line

이러한 각 필드의 의미는 경고 필터에 설명된 대로입니다. 한 줄에 여러 필터를 나열할 때 (PYTHONWARNINGS와 같이), 개별 필터는 쉼표로 구분되고 나중에 나열된 필터가 그 앞에 나열된 필터보다 우선합니다 (왼쪽에서 오른쪽으로 적용되고, 가장 최근에 적용된 필터가 앞서 나온 필터에 우선하기 때문입니다).

일반적으로 사용되는 경고 필터는 모든 경고, 특정 범주의 경고 또는 특정 모듈이나 패키지에서 발생하는 경고에 적용됩니다. 몇 가지 예:

default                      # Show all warnings (even those ignored by default)
ignore                       # Ignore all warnings
error                        # Convert all warnings to errors
error::ResourceWarning       # Treat ResourceWarning messages as errors
default::DeprecationWarning  # Show DeprecationWarning messages
ignore,default:::mymodule    # Only report warnings triggered by "mymodule"
error:::mymodule             # Convert warnings to errors in "mymodule"

기본 경고 필터

기본적으로, 파이썬은 -W 명령 줄 옵션, PYTHONWARNINGS 환경 변수 및 filterwarnings() 호출로 재정의할 수 있는 몇 가지 경고 필터를 설치합니다.

정규 릴리스 빌드에서, 기본 경고 필터에는 다음과 같은 항목이 있습니다 (우선순위 순서로):

default::DeprecationWarning:__main__
ignore::DeprecationWarning
ignore::PendingDeprecationWarning
ignore::ImportWarning
ignore::ResourceWarning

In a debug build, the list of default warning filters is empty.

버전 3.2에서 변경: DeprecationWarning은 이제 PendingDeprecationWarning 에 더해 기본적으로 무시됩니다.

버전 3.7에서 변경: DeprecationWarning은 __main__의 코드에 의해 직접 트리거 될 때 기본적으로 다시 한번 표시됩니다.

버전 3.7에서 변경: BytesWarning은 더는 기본 필터 목록에 나타나지 않으며 대신 -b가 두 번 지정되면 sys.warnoptions를 통해 구성됩니다.

기본 필터 재정의

파이썬으로 작성된 응용 프로그램 개발자는 기본적으로 사용자에게 모든 파이썬 수준 경고를 숨기고, 테스트를 실행하거나 달리 응용 프로그램에 대해 작업할 때만 표시하고 싶을 수 있습니다. 필터 구성을 인터프리터에 전달하는 데 사용되는 sys.warnoptions 어트리뷰트는 경고를 비활성화해야 하는지를 나타내는 마커로 사용할 수 있습니다:

import sys

if not sys.warnoptions:
    import warnings
    warnings.simplefilter("ignore")

파이썬 코드용 테스트 실행기 개발자는 대신 다음과 같은 코드를 사용하여 테스트 대상 코드에 대해 기본적으로 모든 경고가 표시되도록 하는 것이 좋습니다:

import sys

if not sys.warnoptions:
    import os, warnings
    warnings.simplefilter("default") # Change the filter in this process
    os.environ["PYTHONWARNINGS"] = "default" # Also affect subprocesses

마지막으로, __main__ 이외의 이름 공간에서 사용자 코드를 실행하는 대화식 셸 개발자는 다음과 같은 코드를 사용하여 DeprecationWarning 메시지가 기본적으로 표시되도록 하는 것이 좋습니다 (여기서 user_ns는 대화식으로 입력된 코드를 실행하는 데 사용되는 모듈입니다):

import warnings
warnings.filterwarnings("default", category=DeprecationWarning,
                                   module=user_ns.get("__name__"))

일시적인 경고 억제

폐지된 함수처럼, 경고를 발생시킬 것을 알고 있는 코드를 사용하고 있지만, 경고를 보고 싶지 않으면 (명령 줄을 통해 경고가 명시적으로 구성된 경우조차), catch_warnings 컨텍스트 관리자를 사용하여 경고를 억제할 수 있습니다:

import warnings

def fxn():
    warnings.warn("deprecated", DeprecationWarning)

with warnings.catch_warnings():
    warnings.simplefilter("ignore")
    fxn()

컨텍스트 관리자 내에서 모든 경고는 무시됩니다. 이를 통해 폐지된 코드 사용을 인식하지 못하는 다른 코드에 대한 경고를 억제하지 않으면서도 경고를 보는 일 없이 알려진 폐지된 코드를 사용할 수 있습니다. 참고: 이것은 단일 스레드 응용 프로그램에서만 보장될 수 있습니다. 둘 이상의 스레드가 catch_warnings 컨텍스트 관리자를 동시에 사용하면, 동작이 정의되지 않습니다.

경고 테스트

코드가 발생시키는 경고를 테스트하려면, catch_warnings 컨텍스트 관리자를 사용하십시오. 이를 통해 쉽게 테스트할 수 있도록 경고 필터를 일시적으로 변경할 수 있습니다. 예를 들어, 검사할 모든 경고를 캡처하려면 다음을 수행하십시오:

import warnings

def fxn():
    warnings.warn("deprecated", DeprecationWarning)

with warnings.catch_warnings(record=True) as w:
    # Cause all warnings to always be triggered.
    warnings.simplefilter("always")
    # Trigger a warning.
    fxn()
    # Verify some things
    assert len(w) == 1
    assert issubclass(w[-1].category, DeprecationWarning)
    assert "deprecated" in str(w[-1].message)

always 대신 error를 사용하여 모든 경고를 예외로 만들 수도 있습니다. 한 가지 알아야 할 것은 once / default 규칙으로 인해 경고가 이미 발생했으면, 어떤 필터가 설정되어 있더라도 경고와 관련된 경고 레지스트리가 지워지지 않으면 경고가 다시 표시되지 않는다는 것입니다.

일단 컨텍스트 관리자가 종료되면, 경고 필터가 컨텍스트에 진입했을 때의 상태로 복원됩니다. 이것은 테스트 간에 경고 필터가 예기치 않은 방식으로 변경되어 테스트 결과가 불확실해지는 것을 방지합니다. 모듈의 showwarning() 함수도 원래 값으로 복원됩니다. 참고: 이것은 단일 스레드 응용 프로그램에서만 보장될 수 있습니다. 둘 이상의 스레드가 catch_warnings 컨텍스트 관리자를 동시에 사용하면, 동작이 정의되지 않습니다.

같은 종류의 경고를 발생시키는 여러 작업을 테스트할 때, 각 작업이 새로운 경고를 발생시키는지 확인하는 방식으로 테스트하는 것이 중요합니다 (예를 들어 경고가 예외를 발생시키도록 설정하고 작업이 예외를 일으키는지 확인합니다, 각 작업 후에 경고 목록의 길이가 계속 증가하는지 확인합니다, 또는 각 새 작업 전에 경고 목록에서 이전 항목을 삭제합니다).

새 버전의 종속성에 대한 코드 갱신

(파이썬으로 작성된 응용 프로그램의 최종 사용자가 아닌) 파이썬 개발자가 주로 관심을 두는 경고 범주는 기본적으로 무시됩니다.

특히, 이 “기본적으로 무시됨” 목록에는 DeprecationWarning(__main__을 제외한 모든 모듈에서)가 포함되어 있습니다. 이는 개발자가 (표준 라이브러리와 제삼자 패키지 모두에서) 호환성을 깨는 향후 API 변경에 대한 시기적절한 알림을 받기 위해 일반적으로 무시되는 경고를 가시화해서 코드를 테스트해야 한다는 것을 의미합니다.

이상적인 경우, 코드에 적절한 테스트 스위트가 있고, 테스트 실행기는 테스트를 실행할 때 모든 경고를 묵시적으로 활성화합니다 (unittest 모듈에서 제공하는 테스트 실행기가 이렇게 합니다).

덜 이상적인 경우, -Wd 를 파이썬 인터프리터에 전달하거나 (-W default의 줄임 표현입니다), 환경에 PYTHONWARNINGS=default를 설정하여 응용프로그램이 폐지된 인터페이스를 사용하는지를 확인할 수 있습니다. 이를 통해 기본적으로 무시되는 경고를 포함한 모든 경고에 대한 default 처리가 가능합니다. 발생한 경고에 대해 수행할 조치를 변경하려면 -W로 전달되는 인자를 변경할 수 있습니다 (예를 들어 -W error). 어떤 것이 가능한지에 대한 자세한 내용은 -W 플래그를 참조하십시오.

사용 가능한 함수

warnings.warn(message, category=None, stacklevel=1, source=None, *, skip_file_prefixes=())

경고를 발행하거나, 무시하거나 예외를 발생시킵니다. 주어지면 category 인자는 경고 범주 클래스여야 합니다; 기본값은 UserWarning입니다. 또는, message가 Warning 인스턴스일 수 있으며, 이 경우 category는 무시되고 message.__class__가 사용됩니다. 이 경우, 메시지 텍스트는 str(message)입니다. 이 함수는 발행된 특정 경고가 경고 필터에 의해 에러로 변경되면 예외를 발생시킵니다. stacklevel 인자는 다음과 같이 파이썬으로 작성된 래퍼 함수에서 사용할 수 있습니다:

def deprecated_api(message):
    warnings.warn(message, DeprecationWarning, stacklevel=2)

This makes the warning refer to deprecated_api’s caller, rather than to the source of deprecated_api itself (since the latter would defeat the purpose of the warning message).

The skip_file_prefixes keyword argument can be used to indicate which stack frames are ignored when counting stack levels. This can be useful when you want the warning to always appear at call sites outside of a package when a constant stacklevel does not fit all call paths or is otherwise challenging to maintain. If supplied, it must be a tuple of strings. When prefixes are supplied, stacklevel is implicitly overridden to be max(2, stacklevel). To cause a warning to be attributed to the caller from outside of the current package you might write:

# example/lower.py
_warn_skips = (os.path.dirname(__file__),)

def one_way(r_luxury_yacht=None, t_wobbler_mangrove=None):
    if r_luxury_yacht:
        warnings.warn("Please migrate to t_wobbler_mangrove=.",
                      skip_file_prefixes=_warn_skips)

# example/higher.py
from . import lower

def another_way(**kw):
    lower.one_way(**kw)

This makes the warning refer to both the example.lower.one_way() and package.higher.another_way() call sites only from calling code living outside of example package.

제공되면, source는 ResourceWarning을 방출한 파괴된 객체입니다.

버전 3.6에서 변경: source 매개 변수를 추가했습니다.

버전 3.12에서 변경: Added skip_file_prefixes.

warnings.warn_explicit(message, category, filename, lineno, module=None, registry=None, module_globals=None, source=None)

이것은 warn()의 기능에 대한 저수준 인터페이스로서, 메시지, 범주, 파일명 및 줄 번호, 그리고 선택적으로 모듈 이름과 레지스트리(모듈의 __warningregistry__ 딕셔너리이어야 합니다)를 명시적으로 전달합니다. 모듈 이름의 기본값은 .py가 제거된 파일명입니다; 레지스트리가 전달되지 않으면, 경고는 억제되지 않습니다. message는 문자열이고 category는 Warning의 서브 클래스여야 하고, 또는 message가 Warning 인스턴스일 수 있는데, 이 경우 category는 무시됩니다.

제공되면, module_globals는 경고가 발행되는 코드에서 사용 중인 전역 이름 공간이어야 합니다. (이 인자는 zip 파일이나 다른 파일 시스템이 아닌 임포트 소스에서 찾은 모듈의 소스 표시를 지원하는 데 사용됩니다).

제공되면, source는 ResourceWarning을 방출한 파괴된 객체입니다.

버전 3.6에서 변경: source 매개 변수를 추가합니다.

warnings.showwarning(message, category, filename, lineno, file=None, line=None)

파일에 경고를 기록합니다. 기본 구현은 formatwarning(message, category, filename, lineno, line)를 호출하고 결과 문자열을 file에 씁니다, file의 기본값은 sys.stderr입니다. warnings.showwarning에 대입하여 이 함수를 임의의 콜러블로 대체할 수 있습니다. line은 경고 메시지에 포함될 소스 코드 줄입니다; line이 제공되지 않으면, showwarning()은 filename과 lineno로 지정된 줄을 읽으려고 시도합니다.

warnings.formatwarning(message, category, filename, lineno, line=None)

표준 방식으로 경고를 포맷합니다. 내장된 개행 문자를 포함하고 개행 문자로 끝날 수 있는 문자열을 반환합니다. line은 경고 메시지에 포함될 소스 코드 줄입니다; line이 제공되지 않으면, formatwarning()은 filename과 lineno로 지정된 줄을 읽으려고 시도합니다.

warnings.filterwarnings(action, message='', category=Warning, module='', lineno=0, append=False)

경고 필터 명세 목록에 항목을 삽입합니다. 항목은 기본적으로 앞에 삽입됩니다; append가 참이면, 끝에 삽입됩니다. 인자의 형을 확인하고, message와 module 정규식을 컴파일한 후 경고 필터 목록에 튜플로 삽입합니다. 둘 다 특정 경고와 일치하면, 목록 앞쪽에 더 가까운 항목이 목록의 뒷부분에 있는 항목보다 우선합니다. 생략된 인자의 기본값은 모든 것과 일치하는 값입니다.

warnings.simplefilter(action, category=Warning, lineno=0, append=False)

경고 필터 명세 목록에 간단한 항목을 삽입합니다. 함수 매개 변수의 의미는 filterwarnings()와 같지만, 범주와 줄 번호가 일치하는 한 삽입 된 필터가 항상 모든 모듈의 메시지와 일치하기 때문에 정규식이 필요하지 않습니다.

warnings.resetwarnings()

경고 필터를 재설정합니다. 이는 -W 명령 줄 옵션과 simplefilter()에 대한 호출을 포함하여 filterwarnings()에 대한 모든 이전 호출의 영향을 되돌립니다.

@warnings.deprecated(msg, *, category=DeprecationWarning, stacklevel=1)

Decorator to indicate that a class, function or overload is deprecated.

When this decorator is applied to an object, deprecation warnings may be emitted at runtime when the object is used. static type checkers will also generate a diagnostic on usage of the deprecated object.

Usage:

from warnings import deprecated
from typing import overload

@deprecated("Use B instead")
class A:
    pass

@deprecated("Use g instead")
def f():
    pass

@overload
@deprecated("int support is deprecated")
def g(x: int) -> int: ...
@overload
def g(x: str) -> int: ...

The warning specified by category will be emitted at runtime on use of deprecated objects. For functions, that happens on calls; for classes, on instantiation and on creation of subclasses. If the category is None, no warning is emitted at runtime. The stacklevel determines where the warning is emitted. If it is 1 (the default), the warning is emitted at the direct caller of the deprecated object; if it is higher, it is emitted further up the stack. Static type checker behavior is not affected by the category and stacklevel arguments.

The deprecation message passed to the decorator is saved in the __deprecated__ attribute on the decorated object. If applied to an overload, the decorator must be after the @overload decorator for the attribute to exist on the overload as returned by typing.get_overloads().

Added in version 3.13: See PEP 702 [https://peps.python.org/pep-0702/].

사용 가능한 컨텍스트 관리자

class warnings.catch_warnings(*, record=False, module=None, action=None, category=Warning, lineno=0, append=False)

경고 필터와 showwarning() 함수를 복사하고 종료 시 복원하는 컨텍스트 관리자. record 인자가 False(기본값)이면 컨텍스트 관리자는 진입할 때 None을 반환합니다. record가 True이면, 재정의된 showwarning() 함수에 보이는 객체로 점진적으로 채워지는 리스트가 반환됩니다 (sys.stdout 으로의 출력도 억제합니다). 리스트의 각 객체에는 showwarning()에 대한 인자와 이름이 같은 어트리뷰트가 있습니다.

module 인자는 필터가 보호되는 warnings를 임포트 할 때 반환되는 모듈 대신 사용되는 모듈을 취합니다. 이 인자는 주로 warnings 모듈 자체를 테스트하기 위해 존재합니다.

If the action argument is not None, the remaining arguments are passed to simplefilter() as if it were called immediately on entering the context.

See 경고 필터 for the meaning of the category and lineno parameters.

참고

catch_warnings 관리자는 모듈의 showwarning() 함수와 내부 필터 명세 목록을 교체한 다음 나중에 복원하는 방식으로 작동합니다. 이는 컨텍스트 관리자가 전역 상태를 수정한다는 의미이고, 따라서 스레드 안전하지 않습니다.

버전 3.11에서 변경: Added the action, category, lineno, and append parameters.

dataclasses — Data Classes

소스 코드: Lib/dataclasses.py [https://github.com/python/cpython/tree/main/Lib/dataclasses.py]

This module provides a decorator and functions for automatically adding generated special methods such as __init__() and __repr__() to user-defined classes. It was originally described in PEP 557 [https://peps.python.org/pep-0557/].

The member variables to use in these generated methods are defined using PEP 526 [https://peps.python.org/pep-0526/] type annotations. For example, this code:

from dataclasses import dataclass

@dataclass
class InventoryItem:
    """Class for keeping track of an item in inventory."""
    name: str
    unit_price: float
    quantity_on_hand: int = 0

    def total_cost(self) -> float:
        return self.unit_price * self.quantity_on_hand

will add, among other things, a __init__() that looks like:

def __init__(self, name: str, unit_price: float, quantity_on_hand: int = 0):
    self.name = name
    self.unit_price = unit_price
    self.quantity_on_hand = quantity_on_hand

Note that this method is automatically added to the class: it is not directly specified in the InventoryItem definition shown above.

Added in version 3.7.

Module contents

@dataclasses.dataclass(*, init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False, match_args=True, kw_only=False, slots=False, weakref_slot=False)

This function is a decorator that is used to add generated special methods to classes, as described below.

The @dataclass decorator examines the class to find fields. A field is defined as a class variable that has a type annotation. With two exceptions described below, nothing in @dataclass examines the type specified in the variable annotation.

생성된 모든 메서드의 필드 순서는 클래스 정의에 나타나는 순서입니다.

The @dataclass decorator will add various “dunder” methods to the class, described below. If any of the added methods already exist in the class, the behavior depends on the parameter, as documented below. The decorator returns the same class that it is called on; no new class is created.

If @dataclass is used just as a simple decorator with no parameters, it acts as if it has the default values documented in this signature. That is, these three uses of @dataclass are equivalent:

@dataclass
class C:
    ...

@dataclass()
class C:
    ...

@dataclass(init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False,
           match_args=True, kw_only=False, slots=False, weakref_slot=False)
class C:
    ...

The parameters to @dataclass are:

init: If true (the default), a __init__() method will be generated.

If the class already defines __init__(), this parameter is ignored.

repr: If true (the default), a __repr__() method will be generated. The generated repr string will have the class name and the name and repr of each field, in the order they are defined in the class. Fields that are marked as being excluded from the repr are not included. For example: InventoryItem(name='widget', unit_price=3.0, quantity_on_hand=10).

If the class already defines __repr__(), this parameter is ignored.

eq: If true (the default), an __eq__() method will be generated. This method compares the class as if it were a tuple of its fields, in order. Both instances in the comparison must be of the identical type.

If the class already defines __eq__(), this parameter is ignored.

order: If true (the default is False), __lt__(), __le__(), __gt__(), and __ge__() methods will be generated. These compare the class as if it were a tuple of its fields, in order. Both instances in the comparison must be of the identical type. If order is true and eq is false, a ValueError is raised.

If the class already defines any of __lt__(), __le__(), __gt__(), or __ge__(), then TypeError is raised.

unsafe_hash: If False (the default), a __hash__() method is generated according to how eq and frozen are set.

__hash__() is used by built-in hash(), and when objects are added to hashed collections such as dictionaries and sets. Having a __hash__() implies that instances of the class are immutable. Mutability is a complicated property that depends on the programmer’s intent, the existence and behavior of __eq__(), and the values of the eq and frozen flags in the @dataclass decorator.

By default, @dataclass will not implicitly add a __hash__() method unless it is safe to do so. Neither will it add or change an existing explicitly defined __hash__() method. Setting the class attribute __hash__ = None has a specific meaning to Python, as described in the __hash__() documentation.

If __hash__() is not explicitly defined, or if it is set to None, then @dataclass may add an implicit __hash__() method. Although not recommended, you can force @dataclass to create a __hash__() method with unsafe_hash=True. This might be the case if your class is logically immutable but can still be mutated. This is a specialized use case and should be considered carefully.

Here are the rules governing implicit creation of a __hash__() method. Note that you cannot both have an explicit __hash__() method in your dataclass and set unsafe_hash=True; this will result in a TypeError.

If eq and frozen are both true, by default @dataclass will generate a __hash__() method for you. If eq is true and frozen is false, __hash__() will be set to None, marking it unhashable (which it is, since it is mutable). If eq is false, __hash__() will be left untouched meaning the __hash__() method of the superclass will be used (if the superclass is object, this means it will fall back to id-based hashing).

frozen: If true (the default is False), assigning to fields will generate an exception. This emulates read-only frozen instances. If __setattr__() or __delattr__() is defined in the class, then TypeError is raised. See the discussion below.

match_args: If true (the default is True), the __match_args__ tuple will be created from the list of parameters to the generated __init__() method (even if __init__() is not generated, see above). If false, or if __match_args__ is already defined in the class, then __match_args__ will not be generated.

Added in version 3.10.

kw_only: If true (the default value is False), then all fields will be marked as keyword-only. If a field is marked as keyword-only, then the only effect is that the __init__() parameter generated from a keyword-only field must be specified with a keyword when __init__() is called. There is no effect on any other aspect of dataclasses. See the parameter glossary entry for details. Also see the KW_ONLY section.

Added in version 3.10.

slots: If true (the default is False), __slots__ attribute will be generated and new class will be returned instead of the original one. If __slots__ is already defined in the class, then TypeError is raised.

경고

Passing parameters to a base class __init_subclass__() when using slots=True will result in a TypeError. Either use __init_subclass__ with no parameters or use default values as a workaround. See gh-91126 [https://github.com/python/cpython/issues/91126] for full details.

Added in version 3.10.

버전 3.11에서 변경: If a field name is already included in the __slots__ of a base class, it will not be included in the generated __slots__ to prevent overriding them. Therefore, do not use __slots__ to retrieve the field names of a dataclass. Use fields() instead. To be able to determine inherited slots, base class __slots__ may be any iterable, but not an iterator.

weakref_slot: If true (the default is False), add a slot named “__weakref__”, which is required to make an instance weakref-able. It is an error to specify weakref_slot=True without also specifying slots=True.

Added in version 3.11.

필드는 선택적으로 일반적인 파이썬 문법을 사용하여 기본값을 지정할 수 있습니다:

@dataclass
class C:
    a: int       # 'a' has no default value
    b: int = 0   # assign a default value for 'b'

In this example, both a and b will be included in the added __init__() method, which will be defined as:

def __init__(self, a: int, b: int = 0):

TypeError will be raised if a field without a default value follows a field with a default value. This is true whether this occurs in a single class, or as a result of class inheritance.

dataclasses.field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, hash=None, compare=True, metadata=None, kw_only=MISSING, doc=None)

For common and simple use cases, no other functionality is required. There are, however, some dataclass features that require additional per-field information. To satisfy this need for additional information, you can replace the default field value with a call to the provided field() function. For example:

@dataclass
class C:
    mylist: list[int] = field(default_factory=list)

c = C()
c.mylist += [1, 2, 3]

As shown above, the MISSING value is a sentinel object used to detect if some parameters are provided by the user. This sentinel is used because None is a valid value for some parameters with a distinct meaning. No code should directly use the MISSING value.

The parameters to field() are:

default: If provided, this will be the default value for this field. This is needed because the field() call itself replaces the normal position of the default value.

default_factory: If provided, it must be a zero-argument callable that will be called when a default value is needed for this field. Among other purposes, this can be used to specify fields with mutable default values, as discussed below. It is an error to specify both default and default_factory.

init: If true (the default), this field is included as a parameter to the generated __init__() method.

repr: If true (the default), this field is included in the string returned by the generated __repr__() method.

hash: This can be a bool or None. If true, this field is included in the generated __hash__() method. If None (the default), use the value of compare: this would normally be the expected behavior. A field should be considered in the hash if it’s used for comparisons. Setting this value to anything other than None is discouraged.

hash=False 이지만 compare=True 로 설정하는 한 가지 가능한 이유는, 동등 비교에 포함되는 필드가 해시값을 계산하는 데 비용이 많이 들고, 형의 해시값에 이바지하는 다른 필드가 있는 경우입니다. 필드가 해시에서 제외된 경우에도 비교에는 계속 사용됩니다.

compare: If true (the default), this field is included in the generated equality and comparison methods (__eq__(), __gt__(), et al.).

metadata: This can be a mapping or None. None is treated as an empty dict. This value is wrapped in MappingProxyType() to make it read-only, and exposed on the Field object. It is not used at all by Data Classes, and is provided as a third-party extension mechanism. Multiple third-parties can each have their own key, to use as a namespace in the metadata.

kw_only: If true, this field will be marked as keyword-only. This is used when the generated __init__() method’s parameters are computed.

Added in version 3.10.

doc: optional docstring for this field.

Added in version 3.13.

If the default value of a field is specified by a call to field(), then the class attribute for this field will be replaced by the specified default value. If default is not provided, then the class attribute will be deleted. The intent is that after the @dataclass decorator runs, the class attributes will all contain the default values for the fields, just as if the default value itself were specified. For example, after:

@dataclass
class C:
    x: int
    y: int = field(repr=False)
    z: int = field(repr=False, default=10)
    t: int = 20

The class attribute C.z will be 10, the class attribute C.t will be 20, and the class attributes C.x and C.y will not be set.

class dataclasses.Field

Field objects describe each defined field. These objects are created internally, and are returned by the fields() module-level method (see below). Users should never instantiate a Field object directly. Its documented attributes are:

name: The name of the field.

type: The type of the field.

default, default_factory, init, repr, hash, compare, metadata, and kw_only have the identical meaning and values as they do in the field() function.

다른 어트리뷰트도 있을 수 있지만, 내부적인 것이므로 검사하거나 의존해서는 안 됩니다.

dataclasses.fields(class_or_instance)

데이터 클래스의 필드들을 정의하는 Field 객체들의 튜플을 돌려줍니다. 데이터 클래스나 데이터 클래스의 인스턴스를 받아들입니다. 데이터 클래스 나 데이터 클래스의 인스턴스를 전달하지 않으면 TypeError 를 돌려줍니다. ClassVar 또는 InitVar 인 의사 필드는 반환하지 않습니다.

dataclasses.asdict(obj, *, dict_factory=dict)

Converts the dataclass obj to a dict (by using the factory function dict_factory). Each dataclass is converted to a dict of its fields, as name: value pairs. dataclasses, dicts, lists, and tuples are recursed into. Other objects are copied with copy.deepcopy().

Example of using asdict() on nested dataclasses:

@dataclass
class Point:
     x: int
     y: int

@dataclass
class C:
     mylist: list[Point]

p = Point(10, 20)
assert asdict(p) == {'x': 10, 'y': 20}

c = C([Point(0, 0), Point(10, 4)])
assert asdict(c) == {'mylist': [{'x': 0, 'y': 0}, {'x': 10, 'y': 4}]}

To create a shallow copy, the following workaround may be used:

{field.name: getattr(obj, field.name) for field in fields(obj)}

asdict() raises TypeError if obj is not a dataclass instance.

dataclasses.astuple(obj, *, tuple_factory=tuple)

Converts the dataclass obj to a tuple (by using the factory function tuple_factory). Each dataclass is converted to a tuple of its field values. dataclasses, dicts, lists, and tuples are recursed into. Other objects are copied with copy.deepcopy().

이전 예에서 계속하면:

assert astuple(p) == (10, 20)
assert astuple(c) == ([(0, 0), (10, 4)],)

To create a shallow copy, the following workaround may be used:

tuple(getattr(obj, field.name) for field in dataclasses.fields(obj))

astuple() raises TypeError if obj is not a dataclass instance.

dataclasses.make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False, match_args=True, kw_only=False, slots=False, weakref_slot=False, module=None, decorator=dataclass)

Creates a new dataclass with name cls_name, fields as defined in fields, base classes as given in bases, and initialized with a namespace as given in namespace. fields is an iterable whose elements are each either name, (name, type), or (name, type, Field). If just name is supplied, typing.Any is used for type. The values of init, repr, eq, order, unsafe_hash, frozen, match_args, kw_only, slots, and weakref_slot have the same meaning as they do in @dataclass.

If module is defined, the __module__ attribute of the dataclass is set to that value. By default, it is set to the module name of the caller.

The decorator parameter is a callable that will be used to create the dataclass. It should take the class object as a first argument and the same keyword arguments as @dataclass. By default, the @dataclass function is used.

This function is not strictly required, because any Python mechanism for creating a new class with __annotations__ can then apply the @dataclass function to convert that class to a dataclass. This function is provided as a convenience. For example:

C = make_dataclass('C',
                   [('x', int),
                     'y',
                    ('z', int, field(default=5))],
                   namespace={'add_one': lambda self: self.x + 1})

는 다음과 동등합니다:

@dataclass
class C:
    x: int
    y: 'typing.Any'
    z: int = 5

    def add_one(self):
        return self.x + 1

Added in version 3.14: Added the decorator parameter.

dataclasses.replace(obj, /, **changes)

Creates a new object of the same type as obj, replacing fields with values from changes. If obj is not a Data Class, raises TypeError. If keys in changes are not field names of the given dataclass, raises TypeError.

The newly returned object is created by calling the __init__() method of the dataclass. This ensures that __post_init__(), if present, is also called.

Init-only variables without default values, if any exist, must be specified on the call to replace() so that they can be passed to __init__() and __post_init__().

It is an error for changes to contain any fields that are defined as having init=False. A ValueError will be raised in this case.

Be forewarned about how init=False fields work during a call to replace(). They are not copied from the source object, but rather are initialized in __post_init__(), if they’re initialized at all. It is expected that init=False fields will be rarely and judiciously used. If they are used, it might be wise to have alternate class constructors, or perhaps a custom replace() (or similarly named) method which handles instance copying.

Dataclass instances are also supported by generic function copy.replace().

dataclasses.is_dataclass(obj)

Return True if its parameter is a dataclass (including subclasses of a dataclass) or an instance of one, otherwise return False.

(데이터 클래스 자체가 아니라) 데이터 클래스의 인스턴스인지 알아야 한다면 not isinstance(obj, type) 검사를 추가하십시오:

def is_dataclass_instance(obj):
    return is_dataclass(obj) and not isinstance(obj, type)

dataclasses.MISSING

A sentinel value signifying a missing default or default_factory.

dataclasses.KW_ONLY

A sentinel value used as a type annotation. Any fields after a pseudo-field with the type of KW_ONLY are marked as keyword-only fields. Note that a pseudo-field of type KW_ONLY is otherwise completely ignored. This includes the name of such a field. By convention, a name of _ is used for a KW_ONLY field. Keyword-only fields signify __init__() parameters that must be specified as keywords when the class is instantiated.

In this example, the fields y and z will be marked as keyword-only fields:

@dataclass
class Point:
    x: float
    _: KW_ONLY
    y: float
    z: float

p = Point(0, y=1.5, z=2.0)

In a single dataclass, it is an error to specify more than one field whose type is KW_ONLY.

Added in version 3.10.

exception dataclasses.FrozenInstanceError

Raised when an implicitly defined __setattr__() or __delattr__() is called on a dataclass which was defined with frozen=True. It is a subclass of AttributeError.

초기화 후처리

dataclasses.__post_init__()

When defined on the class, it will be called by the generated __init__(), normally as self.__post_init__(). However, if any InitVar fields are defined, they will also be passed to __post_init__() in the order they were defined in the class. If no __init__() method is generated, then __post_init__() will not automatically be called.

다른 용도 중에서도, 하나나 그 이상의 다른 필드에 의존하는 필드 값을 초기화하는데 사용할 수 있습니다. 예를 들면:

@dataclass
class C:
    a: float
    b: float
    c: float = field(init=False)

    def __post_init__(self):
        self.c = self.a + self.b

The __init__() method generated by @dataclass does not call base class __init__() methods. If the base class has an __init__() method that has to be called, it is common to call this method in a __post_init__() method:

class Rectangle:
    def __init__(self, height, width):
        self.height = height
        self.width = width

@dataclass
class Square(Rectangle):
    side: float

    def __post_init__(self):
        super().__init__(self.side, self.side)

Note, however, that in general the dataclass-generated __init__() methods don’t need to be called, since the derived dataclass will take care of initializing all fields of any base class that is a dataclass itself.

See the section below on init-only variables for ways to pass parameters to __post_init__(). Also see the warning about how replace() handles init=False fields.

클래스 변수

One of the few places where @dataclass actually inspects the type of a field is to determine if a field is a class variable as defined in PEP 526 [https://peps.python.org/pep-0526/]. It does this by checking if the type of the field is typing.ClassVar. If a field is a ClassVar, it is excluded from consideration as a field and is ignored by the dataclass mechanisms. Such ClassVar pseudo-fields are not returned by the module-level fields() function.

초기화 전용 변수

Another place where @dataclass inspects a type annotation is to determine if a field is an init-only variable. It does this by seeing if the type of a field is of type dataclasses.InitVar. If a field is an InitVar, it is considered a pseudo-field called an init-only field. As it is not a true field, it is not returned by the module-level fields() function. Init-only fields are added as parameters to the generated __init__() method, and are passed to the optional __post_init__() method. They are not otherwise used by dataclasses.

예를 들어, 클래스를 만들 때 값이 제공되지 않으면, 필드가 데이터베이스로부터 초기화된다고 가정합시다:

@dataclass
class C:
    i: int
    j: int | None = None
    database: InitVar[DatabaseType | None] = None

    def __post_init__(self, database):
        if self.j is None and database is not None:
            self.j = database.lookup('j')

c = C(10, database=my_database)

In this case, fields() will return Field objects for i and j, but not for database.

고정 인스턴스

It is not possible to create truly immutable Python objects. However, by passing frozen=True to the @dataclass decorator you can emulate immutability. In that case, dataclasses will add __setattr__() and __delattr__() methods to the class. These methods will raise a FrozenInstanceError when invoked.

There is a tiny performance penalty when using frozen=True: __init__() cannot use simple assignment to initialize fields, and must use object.__setattr__().

계승

When the dataclass is being created by the @dataclass decorator, it looks through all of the class’s base classes in reverse MRO (that is, starting at object) and, for each dataclass that it finds, adds the fields from that base class to an ordered mapping of fields. After all of the base class fields are added, it adds its own fields to the ordered mapping. All of the generated methods will use this combined, calculated ordered mapping of fields. Because the fields are in insertion order, derived classes override base classes. An example:

@dataclass
class Base:
    x: Any = 15.0
    y: int = 0

@dataclass
class C(Base):
    z: int = 10
    x: int = 15

The final list of fields is, in order, x, y, z. The final type of x is int, as specified in class C.

The generated __init__() method for C will look like:

def __init__(self, x: int = 15, y: int = 0, z: int = 10):

Re-ordering of keyword-only parameters in __init__()

After the parameters needed for __init__() are computed, any keyword-only parameters are moved to come after all regular (non-keyword-only) parameters. This is a requirement of how keyword-only parameters are implemented in Python: they must come after non-keyword-only parameters.

In this example, Base.y, Base.w, and D.t are keyword-only fields, and Base.x and D.z are regular fields:

@dataclass
class Base:
    x: Any = 15.0
    _: KW_ONLY
    y: int = 0
    w: int = 1

@dataclass
class D(Base):
    z: int = 10
    t: int = field(kw_only=True, default=0)

The generated __init__() method for D will look like:

def __init__(self, x: Any = 15.0, z: int = 10, *, y: int = 0, w: int = 1, t: int = 0):

Note that the parameters have been re-ordered from how they appear in the list of fields: parameters derived from regular fields are followed by parameters derived from keyword-only fields.

The relative ordering of keyword-only parameters is maintained in the re-ordered __init__() parameter list.

기본 팩토리 함수

If a field() specifies a default_factory, it is called with zero arguments when a default value for the field is needed. For example, to create a new instance of a list, use:

mylist: list = field(default_factory=list)

If a field is excluded from __init__() (using init=False) and the field also specifies default_factory, then the default factory function will always be called from the generated __init__() function. This happens because there is no other way to give the field an initial value.

가변 기본값

파이썬은 기본 멤버 변숫값을 클래스 어트리뷰트에 저장합니다. 데이터 클래스를 사용하지 않는 이 예제를 생각해보세요:

class C:
    x = []
    def add(self, element):
        self.x.append(element)

o1 = C()
o2 = C()
o1.add(1)
o2.add(2)
assert o1.x == [1, 2]
assert o1.x is o2.x

Note that the two instances of class C share the same class variable x, as expected.

데이터 클래스를 사용해서, 만약 이 코드가 올바르다면:

@dataclass
class D:
    x: list = []      # This code raises ValueError
    def add(self, element):
        self.x.append(element)

비슷한 코드를 생성합니다:

class D:
    x = []
    def __init__(self, x=x):
        self.x = x
    def add(self, element):
        self.x.append(element)

assert D().x is D().x

This has the same issue as the original example using class C. That is, two instances of class D that do not specify a value for x when creating a class instance will share the same copy of x. Because dataclasses just use normal Python class creation they also share this behavior. There is no general way for Data Classes to detect this condition. Instead, the @dataclass decorator will raise a ValueError if it detects an unhashable default parameter. The assumption is that if a value is unhashable, it is mutable. This is a partial solution, but it does protect against many common errors.

기본 팩토리 함수를 사용하면 필드의 기본값으로 가변형의 새 인스턴스를 만들 수 있습니다:

@dataclass
class D:
    x: list = field(default_factory=list)

assert D().x is not D().x

버전 3.11에서 변경: Instead of looking for and disallowing objects of type list, dict, or set, unhashable objects are now not allowed as default values. Unhashability is used to approximate mutability.

Descriptor-typed fields

Fields that are assigned descriptor objects as their default value have the following special behaviors:

The value for the field passed to the dataclass’s __init__() method is passed to the descriptor’s __set__() method rather than overwriting the descriptor object.

Similarly, when getting or setting the field, the descriptor’s __get__() or __set__() method is called rather than returning or overwriting the descriptor object.

To determine whether a field contains a default value, @dataclass will call the descriptor’s __get__() method using its class access form: descriptor.__get__(obj=None, type=cls). If the descriptor returns a value in this case, it will be used as the field’s default. On the other hand, if the descriptor raises AttributeError in this situation, no default value will be provided for the field.

class IntConversionDescriptor:
    def __init__(self, *, default):
        self._default = default

    def __set_name__(self, owner, name):
        self._name = "_" + name

    def __get__(self, obj, type):
        if obj is None:
            return self._default

        return getattr(obj, self._name, self._default)

    def __set__(self, obj, value):
        setattr(obj, self._name, int(value))

@dataclass
class InventoryItem:
    quantity_on_hand: IntConversionDescriptor = IntConversionDescriptor(default=100)

i = InventoryItem()
print(i.quantity_on_hand)   # 100
i.quantity_on_hand = 2.5    # calls __set__ with 2.5
print(i.quantity_on_hand)   # 2

Note that if a field is annotated with a descriptor type, but is not assigned a descriptor object as its default value, the field will act like a normal field.

contextlib — with 문 컨텍스트를 위한 유틸리티

소스 코드: Lib/contextlib.py [https://github.com/python/cpython/tree/main/Lib/contextlib.py]

이 모듈은 with 문이 수반되는 일반적인 작업을 위한 유틸리티를 제공합니다. 자세한 정보는 컨텍스트 관리자 형 과 with 문 컨텍스트 관리자도 참조하십시오.

유틸리티

제공되는 함수와 클래스:

class contextlib.AbstractContextManager

object.__enter__()와 object.__exit__()를 구현하는 클래스의 추상 베이스 클래스. self를 반환하는 object.__enter__()의 기본 구현이 제공되지만 object.__exit__()는 기본적으로 None을 반환하는 추상 메서드입니다. 컨텍스트 관리자 형 의 정의도 참조하십시오.

Added in version 3.6.

class contextlib.AbstractAsyncContextManager

object.__aenter__()와 object.__aexit__()를 구현하는 클래스의 추상 베이스 클래스. self를 반환하는 object.__aenter__()의 기본 구현이 제공되지만 object.__aexit__()는 기본적으로 None을 반환하는 추상 메서드입니다. 비동기 컨텍스트 관리자의 정의도 참조하십시오.

Added in version 3.7.

@contextlib.contextmanager

This function is a decorator that can be used to define a factory function for with statement context managers, without needing to create a class or separate __enter__() and __exit__() methods.

많은 객체가 자체적으로 with 문에서의 사용을 지원하지만, 스스로는 컨텍스트 관리자가 아니고 contextlib.closing과 함께 사용할 close() 메서드를 구현하지 않는 자원을 관리해야 하는 경우가 있습니다.

올바른 자원 관리를 보장하기 위한 추상적인 예는 다음과 같습니다:

from contextlib import contextmanager

@contextmanager
def managed_resource(*args, **kwds):
    # Code to acquire resource, e.g.:
    resource = acquire_resource(*args, **kwds)
    try:
        yield resource
    finally:
        # Code to release resource, e.g.:
        release_resource(resource)

The function can then be used like this:

>>> with managed_resource(timeout=3600) as resource:
...     # Resource is released at the end of this block,
...     # even if code in the block raises an exception

데코레이트 되는 함수는 호출될 때 제너레이터 이터레이터를 반환해야 합니다. 이 이터레이터는 정확히 하나의 값을 산출해야 하며, 이는 with 문의 as 절에 있는 대상에 연결됩니다 (있다면).

제너레이터가 산출하는 지점에서, with 문에 중첩된 블록이 실행됩니다. 그런 다음 블록이 종료된 후 제너레이터가 재개합니다. 블록에서 처리되지 않은 예외가 발생하면, 제너레이터 내부의 yield가 등장한 지점에서 다시 발생합니다. 따라서, try…except…finally 문을 사용하여 에러(있다면)를 잡거나, 어떤 정리가 수행되도록 할 수 있습니다. 예외를 단지 로그 하기 위해 또는 (예외를 완전히 억제하는 대신) 어떤 작업을 수행하기 위해 예외를 잡았다면 제너레이터는 해당 예외를 다시 발생시켜야 합니다. 그렇지 않으면 제너레이터 컨텍스트 관리자가 with 문에 예외가 처리되었음을 표시하고, with 문 바로 다음에 오는 문장으로 실행이 재개됩니다.

contextmanager()는 ContextDecorator를 사용해서, 만들어진 컨텍스트 관리자를 with 문뿐만 아니라 데코레이터로 사용할 수 있습니다. 데코레이터로 사용될 때, 새로운 제너레이터 인스턴스는 각 함수 호출마다 묵시적으로 만들어집니다 (이는 그렇지 않을 경우 contextmanager()에 의해 만들어진 “일회성” 컨텍스트 관리자가 데코레이터로 사용하기 위해 컨텍스트 관리자가 여러 번의 호출을 지원해야 한다는 요구 사항을 충족시킬 수 있도록 합니다) .

버전 3.2에서 변경: ContextDecorator 사용.

@contextlib.asynccontextmanager

contextmanager()와 유사하지만, 비동기 컨텍스트 관리자를 만듭니다.

This function is a decorator that can be used to define a factory function for async with statement asynchronous context managers, without needing to create a class or separate __aenter__() and __aexit__() methods. It must be applied to an asynchronous generator function.

간단한 예:

from contextlib import asynccontextmanager

@asynccontextmanager
async def get_connection():
    conn = await acquire_db_connection()
    try:
        yield conn
    finally:
        await release_db_connection(conn)

async def get_all_users():
    async with get_connection() as conn:
        return conn.query('SELECT ...')

Added in version 3.7.

Context managers defined with asynccontextmanager() can be used either as decorators or with async with statements:

import time
from contextlib import asynccontextmanager

@asynccontextmanager
async def timeit():
    now = time.monotonic()
    try:
        yield
    finally:
        print(f'it took {time.monotonic() - now}s to run')

@timeit()
async def main():
    # ... async code ...

When used as a decorator, a new generator instance is implicitly created on each function call. This allows the otherwise “one-shot” context managers created by asynccontextmanager() to meet the requirement that context managers support multiple invocations in order to be used as decorators.

버전 3.10에서 변경: Async context managers created with asynccontextmanager() can be used as decorators.

contextlib.closing(thing)

블록이 완료될 때 thing을 닫는 컨텍스트 관리자를 반환합니다. 이것은 기본적으로 다음과 동등합니다:

from contextlib import contextmanager

@contextmanager
def closing(thing):
    try:
        yield thing
    finally:
        thing.close()

그리고 다음과 같은 코드를 작성할 수 있도록 합니다:

from contextlib import closing
from urllib.request import urlopen

with closing(urlopen('https://www.python.org')) as page:
    for line in page:
        print(line)

page를 명시적으로 닫을 필요가 없습니다. 에러가 발생하더라도, with 블록이 종료될 때 page.close()가 호출됩니다.

참고

Most types managing resources support the context manager protocol, which closes thing on leaving the with statement. As such, closing() is most useful for third party types that don’t support context managers. This example is purely for illustration purposes, as urlopen() would normally be used in a context manager.

contextlib.aclosing(thing)

Return an async context manager that calls the aclose() method of thing upon completion of the block. This is basically equivalent to:

from contextlib import asynccontextmanager

@asynccontextmanager
async def aclosing(thing):
    try:
        yield thing
    finally:
        await thing.aclose()

Significantly, aclosing() supports deterministic cleanup of async generators when they happen to exit early by break or an exception. For example:

from contextlib import aclosing

async with aclosing(my_generator()) as values:
    async for value in values:
        if value == 42:
            break

This pattern ensures that the generator’s async exit code is executed in the same context as its iterations (so that exceptions and context variables work as expected, and the exit code isn’t run after the lifetime of some task it depends on).

Added in version 3.10.

contextlib.nullcontext(enter_result=None)

__enter__에서 enter_result를 반환하지만, 그 외에는 아무것도 하지 않는 컨텍스트 관리자를 반환합니다. 선택적 컨텍스트 관리자를 위한 대체로 사용하기 위한 것입니다, 예를 들어:

def myfunction(arg, ignore_exceptions=False):
    if ignore_exceptions:
        # Use suppress to ignore all exceptions.
        cm = contextlib.suppress(Exception)
    else:
        # Do not ignore any exceptions, cm has no effect.
        cm = contextlib.nullcontext()
    with cm:
        # Do something

enter_result를 사용하는 예:

def process_file(file_or_path):
    if isinstance(file_or_path, str):
        # If string, open file
        cm = open(file_or_path)
    else:
        # Caller is responsible for closing file
        cm = nullcontext(file_or_path)

    with cm as file:
        # Perform processing on the file

It can also be used as a stand-in for asynchronous context managers:

async def send_http(session=None):
    if not session:
        # If no http session, create it with aiohttp
        cm = aiohttp.ClientSession()
    else:
        # Caller is responsible for closing the session
        cm = nullcontext(session)

    async with cm as session:
        # Send http requests with session

Added in version 3.7.

버전 3.10에서 변경: asynchronous context manager support was added.

contextlib.suppress(*exceptions)

Return a context manager that suppresses any of the specified exceptions if they occur in the body of a with statement and then resumes execution with the first statement following the end of the with statement.

예외를 완전히 억제하는 다른 메커니즘과 마찬가지로, 이 컨텍스트 관리자는 프로그램 실행을 조용히 계속하는 것이 옳은 것으로 알려진 매우 특정한 에러를 다루기 위해서만 사용해야 합니다.

예를 들면:

from contextlib import suppress

with suppress(FileNotFoundError):
    os.remove('somefile.tmp')

with suppress(FileNotFoundError):
    os.remove('someotherfile.tmp')

이 코드는 다음과 동등합니다:

try:
    os.remove('somefile.tmp')
except FileNotFoundError:
    pass

try:
    os.remove('someotherfile.tmp')
except FileNotFoundError:
    pass

이 컨텍스트 관리자는 재진입 가능합니다.

If the code within the with block raises a BaseExceptionGroup, suppressed exceptions are removed from the group. Any exceptions of the group which are not suppressed are re-raised in a new group which is created using the original group’s derive() method.

Added in version 3.4.

버전 3.12에서 변경: suppress now supports suppressing exceptions raised as part of a BaseExceptionGroup.

contextlib.redirect_stdout(new_target)

sys.stdout을 다른 파일이나 파일류 객체로 일시적으로 리디렉션 하기 위한 컨텍스트 관리자.

이 도구는 출력이 stdout에 배선된 기존 함수나 클래스에 유연성을 추가합니다.

For example, the output of help() normally is sent to sys.stdout. You can capture that output in a string by redirecting the output to an io.StringIO object. The replacement stream is returned from the __enter__ method and so is available as the target of the with statement:

with redirect_stdout(io.StringIO()) as f:
    help(pow)
s = f.getvalue()

help()의 출력을 디스크의 파일로 보내려면, 출력을 일반 파일로 리디렉션 하십시오:

with open('help.txt', 'w') as f:
    with redirect_stdout(f):
        help(pow)

help()의 출력을 sys.stderr로 보내려면:

with redirect_stdout(sys.stderr):
    help(pow)

sys.stdout에 대한 전역 부작용은 이 컨텍스트 관리자가 라이브러리 코드와 대부분의 스레드 응용 프로그램에 사용하기에 적합하지 않음을 의미합니다. 또한 서브 프로세스의 출력에는 영향을 미치지 않습니다. 그러나, 여전히 많은 유틸리티 스크립트에 유용한 접근법입니다.

이 컨텍스트 관리자는 재진입 가능합니다.

Added in version 3.4.

contextlib.redirect_stderr(new_target)

redirect_stdout()과 유사하지만, sys.stderr를 다른 파일이나 파일류 객체로 리디렉션 합니다.

이 컨텍스트 관리자는 재진입 가능합니다.

Added in version 3.5.

contextlib.chdir(path)

Non parallel-safe context manager to change the current working directory. As this changes a global state, the working directory, it is not suitable for use in most threaded or async contexts. It is also not suitable for most non-linear code execution, like generators, where the program execution is temporarily relinquished – unless explicitly desired, you should not yield when this context manager is active.

This is a simple wrapper around chdir(), it changes the current working directory upon entering and restores the old one on exit.

이 컨텍스트 관리자는 재진입 가능합니다.

Added in version 3.11.

class contextlib.ContextDecorator

컨텍스트 관리자를 데코레이터로도 사용할 수 있도록 하는 베이스 클래스.

ContextDecorator를 상속하는 컨텍스트 관리자는 일반적인 방식으로 __enter__와 __exit__를 구현해야 합니다. __exit__는 데코레이터로 사용될 때도 선택적 예외 처리를 유지합니다.

ContextDecorator는 contextmanager()에서 사용되므로, 이 기능을 자동으로 얻게 됩니다.

ContextDecorator의 예:

from contextlib import ContextDecorator

class mycontext(ContextDecorator):
    def __enter__(self):
        print('Starting')
        return self

    def __exit__(self, *exc):
        print('Finishing')
        return False

The class can then be used like this:

>>> @mycontext()
... def function():
...     print('The bit in the middle')
...
>>> function()
Starting
The bit in the middle
Finishing

>>> with mycontext():
...     print('The bit in the middle')
...
Starting
The bit in the middle
Finishing

이 변경은 단지 다음 형식의 구성에 대한 편의 문법일 뿐입니다:

def f():
    with cm():
        # Do stuff

ContextDecorator는 대신 다음과 같이 쓸 수 있도록 합니다:

@cm()
def f():
    # Do stuff

cm이 단지 함수의 일부가 아니라 전체 함수에 적용된다는 것을 분명히 합니다 (그리고 들여쓰기 수준을 절약하는 것도 좋습니다).

베이스 클래스가 이미 있는 기존 컨텍스트 관리자는 ContextDecorator를 믹스인 클래스로 사용하여 확장할 수 있습니다:

from contextlib import ContextDecorator

class mycontext(ContextBaseClass, ContextDecorator):
    def __enter__(self):
        return self

    def __exit__(self, *exc):
        return False

참고

데코레이트 된 함수는 여러 번 호출될 수 있어야 해서, 하부 컨텍스트 관리자는 여러 with 문에서의 사용을 지원해야 합니다. 그렇지 않으면, 함수 내에 명시적인 with 문이 있는 원래 구문을 사용해야 합니다.

Added in version 3.2.

class contextlib.AsyncContextDecorator

Similar to ContextDecorator but only for asynchronous functions.

Example of AsyncContextDecorator:

from asyncio import run
from contextlib import AsyncContextDecorator

class mycontext(AsyncContextDecorator):
    async def __aenter__(self):
        print('Starting')
        return self

    async def __aexit__(self, *exc):
        print('Finishing')
        return False

The class can then be used like this:

>>> @mycontext()
... async def function():
...     print('The bit in the middle')
...
>>> run(function())
Starting
The bit in the middle
Finishing

>>> async def function():
...    async with mycontext():
...         print('The bit in the middle')
...
>>> run(function())
Starting
The bit in the middle
Finishing

Added in version 3.10.

class contextlib.ExitStack

다른 컨텍스트 관리자와 정리 함수, 특히 입력 데이터에 의해 선택적이거나 다른 방식으로 구동되는 것들을 프로그래밍 방식으로 쉽게 결합할 수 있도록 설계된 컨텍스트 관리자.

예를 들어, 일련의 파일을 다음과 같이 단일 with 문으로 쉽게 처리할 수 있습니다:

with ExitStack() as stack:
    files = [stack.enter_context(open(fname)) for fname in filenames]
    # All opened files will automatically be closed at the end of
    # the with statement, even if attempts to open files later
    # in the list raise an exception

The __enter__() method returns the ExitStack instance, and performs no additional operations.

각 인스턴스는 인스턴스가 닫힐 때 (명시적으로 혹은 with 문의 끝에서 묵시적으로) 역순으로 호출되는 등록된 콜백의 스택을 유지합니다. 컨텍스트 스택 인스턴스가 가비지 수집될 때 콜백이 묵시적으로 호출되지 않음에 유의하십시오.

이 스택 모델은 __init__ 메서드에서 자원을 확보하는 컨텍스트 관리자(가령 파일 객체)가 올바르게 처리될 수 있도록 사용됩니다.

등록된 콜백이 등록 순서의 역순으로 호출되므로, 여러 개의 중첩된 with 문이 등록된 콜백 집합과 함께 사용된 것처럼 작동합니다. 이것은 예외 처리로도 확장됩니다 - 내부 콜백이 예외를 억제하거나 바꾸면, 외부 콜백에는 갱신된 상태에 따른 인자가 전달됩니다.

탈출 콜백의 스택을 올바르게 되감는 세부 사항을 다루는 비교적 저수준의 API입니다. 응용 프로그램 특정 방식으로 탈출 스택을 조작하는 고수준 컨텍스트 관리자에게 적절한 기반을 제공합니다.

Added in version 3.3.

enter_context(cm)

Enters a new context manager and adds its __exit__() method to the callback stack. The return value is the result of the context manager’s own __enter__() method.

이러한 컨텍스트 관리자는 with 문의 일부로 직접 사용되었다면 일반적으로 했을 것과 마찬가지로 예외를 억제할 수 있습니다.

버전 3.11에서 변경: Raises TypeError instead of AttributeError if cm is not a context manager.

push(exit)

Adds a context manager’s __exit__() method to the callback stack.

As __enter__ is not invoked, this method can be used to cover part of an __enter__() implementation with a context manager’s own __exit__() method.

If passed an object that is not a context manager, this method assumes it is a callback with the same signature as a context manager’s __exit__() method and adds it directly to the callback stack.

By returning true values, these callbacks can suppress exceptions the same way context manager __exit__() methods can.

전달된 객체는 함수에서 반환되어, 이 메서드를 함수 데코레이터로 사용할 수 있도록 합니다.

callback(callback, /, *args, **kwds)

임의의 콜백 함수와 인자를 받아서 콜백 스택에 추가합니다.

다른 메서드와 달리, 이 방법으로 추가된 콜백은 예외를 무시할 수 없습니다 (예외 세부 정보가 전달되지 않기 때문입니다).

전달된 콜백은 함수에서 반환되어, 이 메서드를 함수 데코레이터로 사용할 수 있도록 합니다.

pop_all()

콜백 스택을 새로운 ExitStack 인스턴스로 옮기고 그것을 반환합니다. 이 작업으로 아무런 콜백도 호출되지 않습니다 - 대신, 이제 새 스택이 닫힐 때 (명시적으로나 with 문의 끝에서 묵시적으로) 호출됩니다.

예를 들어, 파일 그룹을 다음과 같이 “전부 아니면 아무것도” 방식으로 열 수 있습니다:

with ExitStack() as stack:
    files = [stack.enter_context(open(fname)) for fname in filenames]
    # Hold onto the close method, but don't call it yet.
    close_files = stack.pop_all().close
    # If opening any file fails, all previously opened files will be
    # closed automatically. If all files are opened successfully,
    # they will remain open even after the with statement ends.
    # close_files() can then be invoked explicitly to close them all.

close()

콜백 스택을 즉시 되감고, 등록 역순으로 콜백을 호출합니다. 등록된 모든 컨텍스트 관리자와 탈출 콜백에 전달되는 인자는 예외가 발생하지 않았음을 나타냅니다.

class contextlib.AsyncExitStack

ExitStack과 유사한 비동기 컨텍스트 관리자, 코루틴 정리 로직을 가질 뿐만 아니라 동기와 비동기 컨텍스트 관리자의 결합을 지원합니다.

The close() method is not implemented; aclose() must be used instead.

coroutine enter_async_context(cm)

Similar to ExitStack.enter_context() but expects an asynchronous context manager.

버전 3.11에서 변경: Raises TypeError instead of AttributeError if cm is not an asynchronous context manager.

push_async_exit(exit)

Similar to ExitStack.push() but expects either an asynchronous context manager or a coroutine function.

push_async_callback(callback, /, *args, **kwds)

Similar to ExitStack.callback() but expects a coroutine function.

coroutine aclose()

Similar to ExitStack.close() but properly handles awaitables.

asynccontextmanager() 에 대한 예제를 계속합니다:

async with AsyncExitStack() as stack:
    connections = [await stack.enter_async_context(get_connection())
        for i in range(5)]
    # All opened connections will automatically be released at the end of
    # the async with statement, even if attempts to open a connection
    # later in the list raise an exception.

Added in version 3.7.

예제와 조리법

이 섹션에서는 contextlib가 제공하는 도구를 효과적으로 사용하기 위한 몇 가지 예와 조리법에 관해 설명합니다.

일정하지 않은 수의 컨텍스트 관리자 지원

ExitStack의 주요 사용 사례는 클래스 설명서에 제공된 것입니다: 일정하지 않은 수의 컨텍스트 관리자와 기타 정리 연산을 단일 with 문에서 지원합니다. 가변성은 사용자 입력(가령 사용자 지정한 파일 모음을 여는 것)에 의해 구동되는 필요한 컨텍스트 관리자의 수나, 일부 선택적인 컨텍스트 관리자의 존재에서 비롯될 수 있습니다:

with ExitStack() as stack:
    for resource in resources:
        stack.enter_context(resource)
    if need_special_resource():
        special = acquire_special_resource()
        stack.callback(release_special_resource, special)
    # Perform operations that use the acquired resources

볼 수 있듯이, ExitStack을 사용하면 with 문을 사용하여 컨텍스트 관리자 프로토콜을 스스로 지원하지 않는 임의의 자원을 쉽게 관리할 수 있습니다.

__enter__ 메서드에서 발생하는 예외 잡기

때때로 with 문 본문이나 컨텍스트 관리자의 __exit__ 메서드에서 발생한 예외를 실수로 포착하지 않으면서, __enter__ 메서드 구현에서 발생하는 예외를 포착하는 것이 바람직합니다. ExitStack을 사용하면 이를 위해 컨텍스트 관리자 프로토콜의 단계를 약간 분리할 수 있습니다:

stack = ExitStack()
try:
    x = stack.enter_context(cm)
except Exception:
    # handle __enter__ exception
else:
    with stack:
        # Handle normal case

실제로 이렇게 할 필요가 있다는 것은 하부 API가 try/except/finally 문과 함께 사용하기 위한 직접 자원 관리 인터페이스를 제공해야 함을 나타내지만, 모든 API가 이런 측면에서 잘 설계된 것은 아닙니다. 컨텍스트 관리자가 유일하게 제공되는 자원 관리 API일 때, ExitStack을 사용하면 with 문에서 직접 처리할 수 없는 다양한 상황을 더 쉽게 처리할 수 있습니다.

__enter__ 구현에서 정리하기

As noted in the documentation of ExitStack.push(), this method can be useful in cleaning up an already allocated resource if later steps in the __enter__() implementation fail.

다음은 선택적 유효성 검증 함수와 함께 자원 확보와 해제 함수를 받아들이고 이를 컨텍스트 관리 프로토콜에 매핑하는 컨텍스트 관리자를 위해 이를 수행하는 예제입니다:

from contextlib import contextmanager, AbstractContextManager, ExitStack

class ResourceManager(AbstractContextManager):

    def __init__(self, acquire_resource, release_resource, check_resource_ok=None):
        self.acquire_resource = acquire_resource
        self.release_resource = release_resource
        if check_resource_ok is None:
            def check_resource_ok(resource):
                return True
        self.check_resource_ok = check_resource_ok

    @contextmanager
    def _cleanup_on_error(self):
        with ExitStack() as stack:
            stack.push(self)
            yield
            # The validation check passed and didn't raise an exception
            # Accordingly, we want to keep the resource, and pass it
            # back to our caller
            stack.pop_all()

    def __enter__(self):
        resource = self.acquire_resource()
        with self._cleanup_on_error():
            if not self.check_resource_ok(resource):
                msg = "Failed validation for {!r}"
                raise RuntimeError(msg.format(resource))
        return resource

    def __exit__(self, *exc_details):
        # We don't need to duplicate any of our resource release logic
        self.release_resource()

try-finally와 플래그 변수 사용 교체하기

때때로 보이는 패턴은 finally 절의 본문을 실행할지를 나타내는 플래그 변수가 있는 try-finally 문입니다. 가장 간단한 형태(단지 대신 except 절을 사용하는 것만으로 이미 처리되었을 수 없는)는 다음과 같습니다:

cleanup_needed = True
try:
    result = perform_operation()
    if result:
        cleanup_needed = False
finally:
    if cleanup_needed:
        cleanup_resources()

다른 try 문 기반 코드와 마찬가지로, 설정 코드와 정리 코드가 임의로 긴 코드 섹션으로 분리될 수 있어서 개발과 검토에 문제가 발생할 수 있습니다.

ExitStack을 사용하면 대신 with 문의 끝에서 실행할 콜백을 등록한 다음 나중에 해당 콜백 실행을 건너뛰기로 할 수 있습니다:

from contextlib import ExitStack

with ExitStack() as stack:
    stack.callback(cleanup_resources)
    result = perform_operation()
    if result:
        stack.pop_all()

This allows the intended cleanup behaviour to be made explicit up front, rather than requiring a separate flag variable.

특정 응용 프로그램에서 이 패턴을 많이 사용한다면, 작은 도우미 클래스를 사용하여 훨씬 더 단순화할 수 있습니다:

from contextlib import ExitStack

class Callback(ExitStack):
    def __init__(self, callback, /, *args, **kwds):
        super().__init__()
        self.callback(callback, *args, **kwds)

    def cancel(self):
        self.pop_all()

with Callback(cleanup_resources) as cb:
    result = perform_operation()
    if result:
        cb.cancel()

자원 정리가 아직 독립 함수로 깔끔하게 번들 되어 있지 않으면, ExitStack.callback()의 데코레이터 형식을 사용하여 자원 정리를 미리 선언할 수 있습니다:

from contextlib import ExitStack

with ExitStack() as stack:
    @stack.callback
    def cleanup_resources():
        ...
    result = perform_operation()
    if result:
        stack.pop_all()

데코레이터 프로토콜의 작동 방식으로 인해, 이 방법으로 선언된 콜백 함수는 아무런 매개 변수도 취할 수 없습니다. 대신 해제할 모든 자원은 클로저(closure) 변수로 액세스해야 합니다.

함수 데코레이터로 컨텍스트 관리자 사용하기

ContextDecorator를 사용하면 일반적인 with 문과 함수 데코레이터 모두로 컨텍스트 관리자를 사용할 수 있습니다.

예를 들어, 진입 시간과 탈출 시간을 추적할 수 있는 로거(logger)로 함수나 문장 그룹을 감싸는 것이 유용할 때가 있습니다. 작업에 대한 함수 데코레이터와 컨텍스트 관리자를 모두 작성하는 대신, ContextDecorator를 상속하면 두 가지 기능을 하나의 정의로 제공합니다:

from contextlib import ContextDecorator
import logging

logging.basicConfig(level=logging.INFO)

class track_entry_and_exit(ContextDecorator):
    def __init__(self, name):
        self.name = name

    def __enter__(self):
        logging.info('Entering: %s', self.name)

    def __exit__(self, exc_type, exc, exc_tb):
        logging.info('Exiting: %s', self.name)

이 클래스의 인스턴스는 컨텍스트 관리자로 사용할 수 있습니다:

with track_entry_and_exit('widget loader'):
    print('Some time consuming activity goes here')
    load_widget()

또한 함수 데코레이터로도 사용할 수 있습니다:

@track_entry_and_exit('widget loader')
def activity():
    print('Some time consuming activity goes here')
    load_widget()

Note that there is one additional limitation when using context managers as function decorators: there’s no way to access the return value of __enter__(). If that value is needed, then it is still necessary to use an explicit with statement.

더 보기

PEP 343 [https://peps.python.org/pep-0343/]- “with” 문

파이썬 with 문의 명세, 배경 및 예

일회용, 재사용 가능 및 재진입 가능 컨텍스트 관리자

대부분의 컨텍스트 관리자는 with 문에서 한 번만 효과적으로 사용할 수 있다는 것을 의미하는 방식으로 작성됩니다. 이러한 일회용 컨텍스트 관리자는 사용될 때마다 새로 만들어야 합니다 - 두 번째로 사용하려고 하면 예외가 발생하거나 올바르게 작동하지 않습니다.

이 흔한 제한 사항은 일반적으로 컨텍스트 관리자가 사용되는 with 문의 헤더에서 컨텍스트 관리자를 직접 만들도록 권고하게 합니다 (위의 모든 사용 예제에서 보이듯이).

파일은 효과적인 일회용 컨텍스트 관리자의 예입니다, 첫 번째 with 문이 파일을 닫아서, 해당 파일 객체를 사용하는 추가 IO 연산을 막기 때문입니다.

contextmanager()를 사용하여 만들어진 컨텍스트 관리자도 일회용 컨텍스트 관리자이며, 두 번째로 사용하려는 경우 하부 제너레이터가 산출에 실패하는 것에 대해 불평합니다:

>>> from contextlib import contextmanager
>>> @contextmanager
... def singleuse():
...     print("Before")
...     yield
...     print("After")
...
>>> cm = singleuse()
>>> with cm:
...     pass
...
Before
After
>>> with cm:
...     pass
...
Traceback (most recent call last):
    ...
RuntimeError: generator didn't yield

재진입 가능 컨텍스트 관리자

더욱 정교한 컨텍스트 관리자는 “재진입”할 수 있습니다. 이러한 컨텍스트 관리자는 여러 with 문에서 사용될 수 있을 뿐만 아니라 이미 같은 컨텍스트 관리자를 사용하는 with 문 내부에서 사용될 수도 있습니다.

threading.RLock is an example of a reentrant context manager, as are suppress(), redirect_stdout(), and chdir(). Here’s a very simple example of reentrant use:

>>> from contextlib import redirect_stdout
>>> from io import StringIO
>>> stream = StringIO()
>>> write_to_stream = redirect_stdout(stream)
>>> with write_to_stream:
...     print("This is written to the stream rather than stdout")
...     with write_to_stream:
...         print("This is also written to the stream")
...
>>> print("This is written directly to stdout")
This is written directly to stdout
>>> print(stream.getvalue())
This is written to the stream rather than stdout
This is also written to the stream

재진입의 실제 예는 서로를 호출하는 여러 함수를 포함할 가능성이 높아서 이 예보다 훨씬 더 복잡합니다.

재진입 가능하다는 것이 스레드 안전하다는 것과 같지 않음에도 유의하십시오. 예를 들어, redirect_stdout()은 sys.stdout을 다른 스트림으로 연결하여 시스템 상태를 전역적으로 수정하므로 명백히 스레드 안전하지 않습니다.

재사용 가능 컨텍스트 관리자

일회용과 재진입 가능 컨텍스트 관리자와 구별되는 “재사용할 수 있는” 컨텍스트 관리자입니다 (또는 재진입 가능 컨텍스트 관리자도 재사용 가능하므로, 완전히 명시적이려면 “재사용할 수 있지만 재진입할 수 없는” 컨텍스트 관리자입니다). 이러한 컨텍스트 관리자는 여러 번 사용되는 것을 지원하지만, 같은 컨텍스트 관리자 인스턴스가 포함하는 with 문에서 이미 사용되었으면 실패합니다 (또는 올바르게 작동하지 않습니다).

threading.Lock은 재사용할 수 있지만 재진입할 수 없는 컨텍스트 관리자의 예입니다 (재진입 가능 록을 위해서는 threading.RLock을 대신 사용해야 합니다).

재사용할 수 있지만 재진입할 수 없는 컨텍스트 관리자의 또 다른 예는 ExitStack인 데, 콜백이 추가된 위치와 관계없이 with 문을 떠날 때 현재 등록된 콜백을 모두 호출하기 때문입니다:

>>> from contextlib import ExitStack
>>> stack = ExitStack()
>>> with stack:
...     stack.callback(print, "Callback: from first context")
...     print("Leaving first context")
...
Leaving first context
Callback: from first context
>>> with stack:
...     stack.callback(print, "Callback: from second context")
...     print("Leaving second context")
...
Leaving second context
Callback: from second context
>>> with stack:
...     stack.callback(print, "Callback: from outer context")
...     with stack:
...         stack.callback(print, "Callback: from inner context")
...         print("Leaving inner context")
...     print("Leaving outer context")
...
Leaving inner context
Callback: from inner context
Callback: from outer context
Leaving outer context

예제의 결과가 보여주듯이, 여러 with 문에서 단일 스택 객체를 재사용하는 것은 올바르게 작동하지만, 중첩을 시도하면 가장 안쪽 with 문 끝에서 스택이 지워지기 때문에 바람직한 동작이 아닙니다.

단일 인스턴스를 재사용하는 대신 별도의 ExitStack 인스턴스를 사용하면 이 문제를 피할 수 있습니다:

>>> from contextlib import ExitStack
>>> with ExitStack() as outer_stack:
...     outer_stack.callback(print, "Callback: from outer context")
...     with ExitStack() as inner_stack:
...         inner_stack.callback(print, "Callback: from inner context")
...         print("Leaving inner context")
...     print("Leaving outer context")
...
Leaving inner context
Callback: from inner context
Leaving outer context
Callback: from outer context

abc — Abstract Base Classes

소스 코드: Lib/abc.py [https://github.com/python/cpython/tree/main/Lib/abc.py]

이 모듈은, PEP 3119 [https://peps.python.org/pep-3119/]에서 설명된 대로, 파이썬에서 추상 베이스 클래스 (ABC) 를 정의하기 위한 기반 구조를 제공합니다; 이것이 왜 파이썬에 추가되었는지는 PEP를 참조하십시오. (ABC를 기반으로 하는 숫자의 형 계층 구조에 관해서는 PEP 3141 [https://peps.python.org/pep-3141/]과 numbers 모듈을 참고하십시오.)

The collections module has some concrete classes that derive from ABCs; these can, of course, be further derived. In addition, the collections.abc submodule has some ABCs that can be used to test whether a class or instance provides a particular interface, for example, if it is hashable or if it is a mapping.

이 모듈은 ABC를 정의하기 위한 메타 클래스 ABCMeta와 상속을 통해 ABC를 정의하는 대안적 방법을 제공하는 도우미 클래스 ABC를 제공합니다:

class abc.ABC

A helper class that has ABCMeta as its metaclass. With this class, an abstract base class can be created by simply deriving from ABC avoiding sometimes confusing metaclass usage, for example:

from abc import ABC

class MyABC(ABC):
    pass

Note that the type of ABC is still ABCMeta, therefore inheriting from ABC requires the usual precautions regarding metaclass usage, as multiple inheritance may lead to metaclass conflicts. One may also define an abstract base class by passing the metaclass keyword and using ABCMeta directly, for example:

from abc import ABCMeta

class MyABC(metaclass=ABCMeta):
    pass

Added in version 3.4.

class abc.ABCMeta

추상 베이스 클래스 (ABC)를 정의하기 위한 메타 클래스.

이 메타 클래스를 사용하여 ABC를 만듭니다. ABC는 직접 서브 클래싱 될 수 있으며 믹스인 클래스의 역할을 합니다. 관련 없는 구상 클래스(심지어 내장 클래스도)와 관련 없는 ABC를 “가상 서브 클래스”로 등록 할 수 있습니다 – 이들과 이들의 서브 클래스는 내장 issubclass() 함수에 의해 등록하는 ABC의 서브 클래스로 간주합니다. 하지만 등록하는 ABC는 그들의 MRO (메서드 결정 순서)에 나타나지 않을 것이고, 등록하는 ABC가 정의한 메서드 구현도 호출할 수 없을 것입니다 (super()를 통해서도 가능하지 않습니다). [1]

Classes created with a metaclass of ABCMeta have the following method:

register(subclass)

이 ABC의 “가상 서브 클래스”로 subclass 를 등록합니다. 예를 들면:

from abc import ABC

class MyABC(ABC):
    pass

MyABC.register(tuple)

assert issubclass(tuple, MyABC)
assert isinstance((), MyABC)

버전 3.3에서 변경: 클래스 데코레이터로 사용할 수 있도록, 등록된 subclass 돌려줍니다.

버전 3.4에서 변경: To detect calls to register(), you can use the get_cache_token() function.

추상 베이스 클래스에서 다음 메서드를 재정의할 수도 있습니다:

__subclasshook__(subclass)

(반드시 클래스 메서드로 정의되어야 합니다.)

Check whether subclass is considered a subclass of this ABC. This means that you can customize the behavior of issubclass() further without the need to call register() on every class you want to consider a subclass of the ABC. (This class method is called from the __subclasscheck__() method of the ABC.)

This method should return True, False or NotImplemented. If it returns True, the subclass is considered a subclass of this ABC. If it returns False, the subclass is not considered a subclass of this ABC, even if it would normally be one. If it returns NotImplemented, the subclass check is continued with the usual mechanism.

이러한 개념들의 시연으로, 이 예제 ABC 정의를 보십시오:

class Foo:
    def __getitem__(self, index):
        ...
    def __len__(self):
        ...
    def get_iterator(self):
        return iter(self)

class MyIterable(ABC):

    @abstractmethod
    def __iter__(self):
        while False:
            yield None

    def get_iterator(self):
        return self.__iter__()

    @classmethod
    def __subclasshook__(cls, C):
        if cls is MyIterable:
            if any("__iter__" in B.__dict__ for B in C.__mro__):
                return True
        return NotImplemented

MyIterable.register(Foo)

The ABC MyIterable defines the standard iterable method, __iter__(), as an abstract method. The implementation given here can still be called from subclasses. The get_iterator() method is also part of the MyIterable abstract base class, but it does not have to be overridden in non-abstract derived classes.

The __subclasshook__() class method defined here says that any class that has an __iter__() method in its __dict__ (or in that of one of its base classes, accessed via the __mro__ list) is considered a MyIterable too.

Finally, the last line makes Foo a virtual subclass of MyIterable, even though it does not define an __iter__() method (it uses the old-style iterable protocol, defined in terms of __len__() and __getitem__()). Note that this will not make get_iterator available as a method of Foo, so it is provided separately.

The abc module also provides the following decorator:

@abc.abstractmethod

추상 메서드를 나타내는 데코레이터.

Using this decorator requires that the class’s metaclass is ABCMeta or is derived from it. A class that has a metaclass derived from ABCMeta cannot be instantiated unless all of its abstract methods and properties are overridden. The abstract methods can be called using any of the normal ‘super’ call mechanisms. abstractmethod() may be used to declare abstract methods for properties and descriptors.

Dynamically adding abstract methods to a class, or attempting to modify the abstraction status of a method or class once it is created, are only supported using the update_abstractmethods() function. The abstractmethod() only affects subclasses derived using regular inheritance; “virtual subclasses” registered with the ABC’s register() method are not affected.

When abstractmethod() is applied in combination with other method descriptors, it should be applied as the innermost decorator, as shown in the following usage examples:

class C(ABC):
    @abstractmethod
    def my_abstract_method(self, arg1):
        ...
    @classmethod
    @abstractmethod
    def my_abstract_classmethod(cls, arg2):
        ...
    @staticmethod
    @abstractmethod
    def my_abstract_staticmethod(arg3):
        ...

    @property
    @abstractmethod
    def my_abstract_property(self):
        ...
    @my_abstract_property.setter
    @abstractmethod
    def my_abstract_property(self, val):
        ...

    @abstractmethod
    def _get_x(self):
        ...
    @abstractmethod
    def _set_x(self, val):
        ...
    x = property(_get_x, _set_x)

In order to correctly interoperate with the abstract base class machinery, the descriptor must identify itself as abstract using __isabstractmethod__. In general, this attribute should be True if any of the methods used to compose the descriptor are abstract. For example, Python’s built-in property does the equivalent of:

class Descriptor:
    ...
    @property
    def __isabstractmethod__(self):
        return any(getattr(f, '__isabstractmethod__', False) for
                   f in (self._fget, self._fset, self._fdel))

참고

자바 추상 메서드와 달리, 이 추상 메서드는 구현을 가질 수 있습니다. 이 구현은 그것을 재정의하는 클래스에서 super() 메커니즘을 통해 호출 할 수 있습니다. 이는 협업적 다중 상속을 사용하는 프레임워크에서 super-호출의 종점으로 유용 할 수 있습니다.

The abc module also supports the following legacy decorators:

@abc.abstractclassmethod

Added in version 3.2.

버전 3.3부터 폐지됨: 이제 classmethod 와 abstractmethod() 를 함께 사용할 수 있어서, 이 데코레이터는 필요 없습니다.

내장 classmethod() 의 서브 클래스로, 추상 classmethod를 나타냅니다. 그 외에는 abstractmethod() 와 유사합니다.

classmethod() 데코레이터가 이제 추상 메서드에 적용될 때 추상으로 정확하게 식별되기 때문에, 이 특별한 경우는 폐지되었습니다.:

class C(ABC):
    @classmethod
    @abstractmethod
    def my_abstract_classmethod(cls, arg):
        ...

@abc.abstractstaticmethod

Added in version 3.2.

버전 3.3부터 폐지됨: 이제 staticmethod 와 abstractmethod() 를 함께 사용할 수 있어서, 이 데코레이터는 필요 없습니다.

내장 staticmethod() 의 서브 클래스로, 추상 staticmethod를 나타냅니다. 그 외에는 abstractmethod() 와 유사합니다.

staticmethod() 데코레이터가 이제 추상 메서드에 적용될 때 추상으로 정확하게 식별되기 때문에, 이 특별한 경우는 폐지되었습니다.:

class C(ABC):
    @staticmethod
    @abstractmethod
    def my_abstract_staticmethod(arg):
        ...

@abc.abstractproperty

버전 3.3부터 폐지됨: 이제 property, property.getter(), property.setter(), property.deleter() 와 abstractmethod() 를 함께 사용할 수 있어서, 이 데코레이터는 필요 없습니다.

내장 property() 의 서브 클래스로, 추상 property를 나타냅니다.

property() 데코레이터가 이제 추상 메서드에 적용될 때 추상으로 정확하게 식별되기 때문에, 이 특별한 경우는 폐지되었습니다.:

class C(ABC):
    @property
    @abstractmethod
    def my_abstract_property(self):
        ...

위의 예제는 읽기 전용 프로퍼티를 정의합니다; 하나나 그 이상의 하부 메서드를 추상으로 적절하게 표시하여 읽기-쓰기 추상 프로퍼티를 정의할 수도 있습니다:

class C(ABC):
    @property
    def x(self):
        ...

    @x.setter
    @abstractmethod
    def x(self, val):
        ...

일부 구성 요소만 추상인 경우, 서브 클래스에서 구상 프로퍼티를 만들기 위해서는 해당 구성 요소만 갱신하면 됩니다:

class D(C):
    @C.x.setter
    def x(self, val):
        ...

The abc module also provides the following functions:

abc.get_cache_token()

현재의 추상 베이스 클래스 캐시 토큰을 반환합니다.

토큰은 가상 서브 클래스를 위한 추상 베이스 클래스 캐시의 현재 버전을 식별하는 (동등성 검사를 지원하는) 불투명 객체입니다. 임의의 ABC에서 ABCMeta.register() 가 호출될 때마다 토큰이 변경됩니다.

Added in version 3.4.

abc.update_abstractmethods(cls)

A function to recalculate an abstract class’s abstraction status. This function should be called if a class’s abstract methods have been implemented or changed after it was created. Usually, this function should be called from within a class decorator.

Returns cls, to allow usage as a class decorator.

If cls is not an instance of ABCMeta, does nothing.

참고

This function assumes that cls’s superclasses are already updated. It does not update any subclasses.

Added in version 3.10.

각주

[1]

C++ 프로그래머는 파이썬의 가상 베이스 클래스 개념이 C++과 다르다는 것을 알아야 합니다.

atexit — Exit handlers

atexit 모듈은 정리 함수를 등록하고 해제하는 함수를 정의합니다. 이렇게 등록된 함수는 정상적인 인터프리터 종료 시 자동으로 실행됩니다. atexit는 이 함수들을 등록된 역순 으로 실행합니다; A, B, C 를 등록하면, 인터프리터 종료 시각에 C, B, A 순서로 실행됩니다.

참고: 이 모듈을 통해 등록된 함수는 다음과 같은 경우 호출되지 않습니다. 프로그램이 파이썬이 처리하지 않는 시그널에 의해 종료될 때. 파이썬의 치명적인 내부 에러가 감지되었을 때. os._exit() 가 호출될 때.

Note: The effect of registering or unregistering functions from within a cleanup function is undefined.

버전 3.7에서 변경: C-API 서브 인터프리터와 함께 사용될 때, 등록된 함수는 등록된 인터프리터에 국지적입니다.

atexit.register(func, *args, **kwargs)

func 를 종료 시에 실행할 함수로 등록합니다. func 에 전달되어야 하는 선택적 인자는 register() 에 인자로 전달되어야 합니다. 같은 함수와 인자를 두 번 이상 등록 할 수 있습니다.

정상적인 프로그램 종료 시에 (예를 들어, sys.exit() 가 호출되거나 주 모듈의 실행이 완료된 경우에), 등록된 모든 함수는 후입선출 순서로 호출됩니다. 낮은 수준의 모듈은 일반적으로 상위 수준 모듈보다 먼저 임포트 되기 때문에 나중에 정리해야 한다는 가정입니다.

If an exception is raised during execution of the exit handlers, a traceback is printed (unless SystemExit is raised) and the exception information is saved. After all exit handlers have had a chance to run, the last exception to be raised is re-raised.

이 함수는 func 을 반환하므로 데코레이터로 사용할 수 있습니다.

경고

Starting new threads or calling os.fork() from a registered function can lead to race condition between the main Python runtime thread freeing thread states while internal threading routines or the new process try to use that state. This can lead to crashes rather than clean shutdown.

버전 3.12에서 변경: Attempts to start a new thread or os.fork() a new process in a registered function now leads to RuntimeError.

atexit.unregister(func)

Remove func from the list of functions to be run at interpreter shutdown. unregister() silently does nothing if func was not previously registered. If func has been registered more than once, every occurrence of that function in the atexit call stack will be removed. Equality comparisons (==) are used internally during unregistration, so function references do not need to have matching identities.

더 보기

모듈 readline

readline 히스토리 파일을 읽고 쓰는 atexit 의 유용한 예.

atexit 예제

다음의 간단한 예제는, 모듈이 임포트 될 때 파일에서 카운터를 읽고 프로그램이 종료할 때 프로그램의 명시적인 호출에 의존하지 않고 카운터의 변경된 값을 자동으로 저장하는 방법을 보여줍니다.:

try:
    with open('counterfile') as infile:
        _count = int(infile.read())
except FileNotFoundError:
    _count = 0

def incrcounter(n):
    global _count
    _count = _count + n

def savecounter():
    with open('counterfile', 'w') as outfile:
        outfile.write('%d' % _count)

import atexit

atexit.register(savecounter)

위치 및 키워드 인자가 등록된 함수가 호출될 때 전달되도록 register() 에 전달할 수 있습니다:

def goodbye(name, adjective):
    print('Goodbye %s, it was %s to meet you.' % (name, adjective))

import atexit

atexit.register(goodbye, 'Donny', 'nice')
# or:
atexit.register(goodbye, adjective='nice', name='Donny')

데코레이터 로 사용하기:

import atexit

@atexit.register
def goodbye():
    print('You are now leaving the Python sector.')

이 방법은 인자 없이 호출할 수 있는 함수에서만 작동합니다.

traceback — Print or retrieve a stack traceback

소스 코드: Lib/traceback.py [https://github.com/python/cpython/tree/main/Lib/traceback.py]

This module provides a standard interface to extract, format and print stack traces of Python programs. It is more flexible than the interpreter’s default traceback display, and therefore makes it possible to configure certain aspects of the output. Finally, it contains a utility for capturing enough information about an exception to print it later, without the need to save a reference to the actual exception. Since exceptions can be the roots of large objects graph, this utility can significantly improve memory management.

The module uses traceback objects — these are objects of type types.TracebackType, which are assigned to the __traceback__ field of BaseException instances.

더 보기

Module faulthandler

Used to dump Python tracebacks explicitly, on a fault, after a timeout, or on a user signal.

Module pdb

Interactive source code debugger for Python programs.

The module’s API can be divided into two parts:

Module-level functions offering basic functionality, which are useful for interactive inspection of exceptions and tracebacks.

TracebackException class and its helper classes StackSummary and FrameSummary. These offer both more flexibility in the output generated and the ability to store the information necessary for later formatting without holding references to actual exception and traceback objects.

Module-Level Functions

traceback.print_tb(tb, limit=None, file=None)

Print up to limit stack trace entries from traceback object tb (starting from the caller’s frame) if limit is positive. Otherwise, print the last abs(limit) entries. If limit is omitted or None, all entries are printed. If file is omitted or None, the output goes to sys.stderr; otherwise it should be an open file or file-like object to receive the output.

참고

The meaning of the limit parameter is different than the meaning of sys.tracebacklimit. A negative limit value corresponds to a positive value of sys.tracebacklimit, whereas the behaviour of a positive limit value cannot be achieved with sys.tracebacklimit.

버전 3.5에서 변경: 음수 limit 지원을 추가했습니다.

traceback.print_exception(exc, /, [value, tb, ]limit=None, file=None, chain=True)

Print exception information and stack trace entries from traceback object tb to file. This differs from print_tb() in the following ways:

tb가 None이 아니면, 헤더 Traceback (most recent call last):를 인쇄합니다.

it prints the exception type and value after the stack trace

type(value)가 SyntaxError고 value가 적절한 형식을 가지면, 에러의 대략적인 위치를 나타내는 캐럿(caret)과 함께 문법 에러가 발생한 줄을 인쇄합니다.

Since Python 3.10, instead of passing value and tb, an exception object can be passed as the first argument. If value and tb are provided, the first argument is ignored in order to provide backwards compatibility.

The optional limit argument has the same meaning as for print_tb(). If chain is true (the default), then chained exceptions (the __cause__ or __context__ attributes of the exception) will be printed as well, like the interpreter itself does when printing an unhandled exception.

버전 3.5에서 변경: etype 인자는 무시되고 value 형에서 유추됩니다.

버전 3.10에서 변경: The etype parameter has been renamed to exc and is now positional-only.

traceback.print_exc(limit=None, file=None, chain=True)

This is a shorthand for print_exception(sys.exception(), limit, file, chain).

traceback.print_last(limit=None, file=None, chain=True)

This is a shorthand for print_exception(sys.last_exc, limit, file, chain). In general it will work only after an exception has reached an interactive prompt (see sys.last_exc).

traceback.print_stack(f=None, limit=None, file=None)

Print up to limit stack trace entries (starting from the invocation point) if limit is positive. Otherwise, print the last abs(limit) entries. If limit is omitted or None, all entries are printed. The optional f argument can be used to specify an alternate stack frame to start. The optional file argument has the same meaning as for print_tb().

버전 3.5에서 변경: 음수 limit 지원을 추가했습니다.

traceback.extract_tb(tb, limit=None)

Return a StackSummary object representing a list of “pre-processed” stack trace entries extracted from the traceback object tb. It is useful for alternate formatting of stack traces. The optional limit argument has the same meaning as for print_tb(). A “pre-processed” stack trace entry is a FrameSummary object containing attributes filename, lineno, name, and line representing the information that is usually printed for a stack trace.

traceback.extract_stack(f=None, limit=None)

Extract the raw traceback from the current stack frame. The return value has the same format as for extract_tb(). The optional f and limit arguments have the same meaning as for print_stack().

traceback.format_list(extracted_list)

extract_tb()나 extract_stack()이 반환한 튜플이나 FrameSummary 객체의 리스트가 제공되면, 인쇄할 준비가 된 문자열의 리스트를 반환합니다. 결과 리스트의 각 문자열은 인자 리스트에서 같은 인덱스를 가진 항목에 해당합니다. 각 문자열은 줄 바꿈으로 끝납니다; 소스 텍스트 줄이 None이 아닌 항목의 경우, 문자열에 내부 줄 바꿈도 포함될 수 있습니다.

traceback.format_exception_only(exc, /, [value, ]*, show_group=False)

Format the exception part of a traceback using an exception value such as given by sys.last_value. The return value is a list of strings, each ending in a newline. The list contains the exception’s message, which is normally a single string; however, for SyntaxError exceptions, it contains several lines that (when printed) display detailed information about where the syntax error occurred. Following the message, the list contains the exception’s notes.

Since Python 3.10, instead of passing value, an exception object can be passed as the first argument. If value is provided, the first argument is ignored in order to provide backwards compatibility.

When show_group is True, and the exception is an instance of BaseExceptionGroup, the nested exceptions are included as well, recursively, with indentation relative to their nesting depth.

버전 3.10에서 변경: The etype parameter has been renamed to exc and is now positional-only.

버전 3.11에서 변경: The returned list now includes any notes attached to the exception.

버전 3.13에서 변경: show_group parameter was added.

traceback.format_exception(exc, /, [value, tb, ]limit=None, chain=True)

스택 트레이스와 예외 정보를 포맷합니다. 인자는 print_exception()의 해당하는 인자와 같은 의미입니다. 반환 값은 각각 줄 바꿈으로 끝나고 일부는 내부 줄 바꿈을 포함하는 문자열의 리스트입니다. 이 줄들을 이어붙여서 인쇄하면, print_exception()과 정확히 같은 텍스트가 인쇄됩니다.

버전 3.5에서 변경: etype 인자는 무시되고 value 형에서 유추됩니다.

버전 3.10에서 변경: This function’s behavior and signature were modified to match print_exception().

traceback.format_exc(limit=None, chain=True)

이것은 print_exc(limit)와 비슷하지만, 파일로 인쇄하는 대신 문자열을 반환합니다.

traceback.format_tb(tb, limit=None)

format_list(extract_tb(tb, limit))의 줄임 표현입니다.

traceback.format_stack(f=None, limit=None)

format_list(extract_stack(f, limit))의 줄임 표현입니다.

traceback.clear_frames(tb)

Clears the local variables of all the stack frames in a traceback tb by calling the clear() method of each frame object.

Added in version 3.4.

traceback.walk_stack(f)

Walk a stack following f.f_back from the given frame, yielding the frame and line number for each frame. If f is None, the current stack is used. This helper is used with StackSummary.extract().

Added in version 3.5.

traceback.walk_tb(tb)

Walk a traceback following tb_next yielding the frame and line number for each frame. This helper is used with StackSummary.extract().

Added in version 3.5.

TracebackException Objects

Added in version 3.5.

TracebackException objects are created from actual exceptions to capture data for later printing. They offer a more lightweight method of storing this information by avoiding holding references to traceback and frame objects In addition, they expose more options to configure the output compared to the module-level functions described above.

class traceback.TracebackException(exc_type, exc_value, exc_traceback, *, limit=None, lookup_lines=True, capture_locals=False, compact=False, max_group_width=15, max_group_depth=10)

Capture an exception for later rendering. The meaning of limit, lookup_lines and capture_locals are as for the StackSummary class.

If compact is true, only data that is required by TracebackException’s format() method is saved in the class attributes. In particular, the __context__ field is calculated only if __cause__ is None and __suppress_context__ is false.

locals가 포착되면, 트레이스백에도 표시됨에 유의하십시오.

max_group_width and max_group_depth control the formatting of exception groups (see BaseExceptionGroup). The depth refers to the nesting level of the group, and the width refers to the size of a single exception group’s exceptions array. The formatted output is truncated when either limit is exceeded.

버전 3.10에서 변경: Added the compact parameter.

버전 3.11에서 변경: Added the max_group_width and max_group_depth parameters.

__cause__

A TracebackException of the original __cause__.

__context__

A TracebackException of the original __context__.

exceptions

If self represents an ExceptionGroup, this field holds a list of TracebackException instances representing the nested exceptions. Otherwise it is None.

Added in version 3.11.

__suppress_context__

The __suppress_context__ value from the original exception.

__notes__

The __notes__ value from the original exception, or None if the exception does not have any notes. If it is not None is it formatted in the traceback after the exception string.

Added in version 3.11.

stack

트레이스백을 나타내는 StackSummary.

exc_type

원래 트레이스백의 클래스.

버전 3.13부터 폐지됨.

exc_type_str

String display of the class of the original exception.

Added in version 3.13.

filename

문법 에러일 때 - 에러가 발생한 파일 이름.

lineno

문법 에러일 때 - 에러가 발생한 줄 번호.

end_lineno

For syntax errors - the end line number where the error occurred. Can be None if not present.

Added in version 3.10.

text

문법 에러일 때 - 에러가 발생한 텍스트.

offset

문법 에러일 때 - 에러가 발생한 텍스트에서의 오프셋.

end_offset

For syntax errors - the end offset into the text where the error occurred. Can be None if not present.

Added in version 3.10.

msg

문법 에러일 때 - 컴파일러 에러 메시지.

classmethod from_exception(exc, *, limit=None, lookup_lines=True, capture_locals=False)

나중에 렌더링하기 위해 예외를 포착합니다. limit, lookup_lines 및 capture_locals는 StackSummary 클래스와 같습니다.

locals가 포착되면, 트레이스백에도 표시됨에 유의하십시오.

print(*, file=None, chain=True)

Print to file (default sys.stderr) the exception information returned by format().

Added in version 3.11.

format(*, chain=True)

예외를 포맷합니다.

If chain is not True, __cause__ and __context__ will not be formatted.

반환 값은 각각 줄 바꿈으로 끝나고 일부는 내부 줄 바꿈을 포함하는 문자열의 제너레이터입니다. print_exception()은 단지 파일에 줄을 인쇄하는 이 메서드를 둘러싸는 래퍼입니다.

format_exception_only(*, show_group=False)

트레이스백의 예외 부분을 포맷합니다.

반환 값은 각각 줄 바꿈으로 끝나는 문자열의 제너레이터입니다.

When show_group is False, the generator emits the exception’s message followed by its notes (if it has any). The exception message is normally a single string; however, for SyntaxError exceptions, it consists of several lines that (when printed) display detailed information about where the syntax error occurred.

When show_group is True, and the exception is an instance of BaseExceptionGroup, the nested exceptions are included as well, recursively, with indentation relative to their nesting depth.

버전 3.11에서 변경: The exception’s notes are now included in the output.

버전 3.13에서 변경: Added the show_group parameter.

StackSummary Objects

Added in version 3.5.

StackSummary objects represent a call stack ready for formatting.

class traceback.StackSummary

classmethod extract(frame_gen, *, limit=None, lookup_lines=True, capture_locals=False)

Construct a StackSummary object from a frame generator (such as is returned by walk_stack() or walk_tb()).

If limit is supplied, only this many frames are taken from frame_gen. If lookup_lines is False, the returned FrameSummary objects will not have read their lines in yet, making the cost of creating the StackSummary cheaper (which may be valuable if it may not actually get formatted). If capture_locals is True the local variables in each FrameSummary are captured as object representations.

버전 3.12에서 변경: Exceptions raised from repr() on a local variable (when capture_locals is True) are no longer propagated to the caller.

classmethod from_list(a_list)

Construct a StackSummary object from a supplied list of FrameSummary objects or old-style list of tuples. Each tuple should be a 4-tuple with filename, lineno, name, line as the elements.

format()

Returns a list of strings ready for printing. Each string in the resulting list corresponds to a single frame from the stack. Each string ends in a newline; the strings may contain internal newlines as well, for those items with source text lines.

같은 프레임과 줄의 긴 시퀀스의 경우, 처음 몇 번의 반복이 표시된 다음, 정확한 추가의 반복 횟수를 나타내는 요약 줄이 표시됩니다.

버전 3.6에서 변경: 반복되는 프레임의 긴 시퀀스가 이제 축약됩니다.

format_frame_summary(frame_summary)

Returns a string for printing one of the frames involved in the stack. This method is called for each FrameSummary object to be printed by StackSummary.format(). If it returns None, the frame is omitted from the output.

Added in version 3.11.

FrameSummary Objects

Added in version 3.5.

A FrameSummary object represents a single frame in a traceback.

class traceback.FrameSummary(filename, lineno, name, lookup_line=True, locals=None, line=None)

Represents a single frame in the traceback or stack that is being formatted or printed. It may optionally have a stringified version of the frame’s locals included in it. If lookup_line is False, the source code is not looked up until the FrameSummary has the line attribute accessed (which also happens when casting it to a tuple). line may be directly provided, and will prevent line lookups happening at all. locals is an optional local variable mapping, and if supplied the variable representations are stored in the summary for later display.

FrameSummary instances have the following attributes:

filename

The filename of the source code for this frame. Equivalent to accessing f.f_code.co_filename on a frame object f.

lineno

The line number of the source code for this frame.

name

Equivalent to accessing f.f_code.co_name on a frame object f.

line

A string representing the source code for this frame, with leading and trailing whitespace stripped. If the source is not available, it is None.

Examples of Using the Module-Level Functions

이 간단한 예제는 표준 파이썬 대화식 인터프리터 루프와 비슷하지만 (하지만 덜 유용한) 기본적인 읽기-평가-인쇄 루프를 구현합니다. 인터프리터 루프의 더욱 완전한 구현은 code 모듈을 참조하십시오.

import sys, traceback

def run_user_code(envdir):
    source = input(">>> ")
    try:
        exec(source, envdir)
    except Exception:
        print("Exception in user code:")
        print("-"*60)
        traceback.print_exc(file=sys.stdout)
        print("-"*60)

envdir = {}
while True:
    run_user_code(envdir)

다음 예제는 예외와 추적을 인쇄하고 포맷하는 다양한 방법을 보여줍니다:

import sys, traceback

def lumberjack():
    bright_side_of_life()

def bright_side_of_life():
    return tuple()[0]

try:
    lumberjack()
except IndexError as exc:
    print("*** print_tb:")
    traceback.print_tb(exc.__traceback__, limit=1, file=sys.stdout)
    print("*** print_exception:")
    traceback.print_exception(exc, limit=2, file=sys.stdout)
    print("*** print_exc:")
    traceback.print_exc(limit=2, file=sys.stdout)
    print("*** format_exc, first and last line:")
    formatted_lines = traceback.format_exc().splitlines()
    print(formatted_lines[0])
    print(formatted_lines[-1])
    print("*** format_exception:")
    print(repr(traceback.format_exception(exc)))
    print("*** extract_tb:")
    print(repr(traceback.extract_tb(exc.__traceback__)))
    print("*** format_tb:")
    print(repr(traceback.format_tb(exc.__traceback__)))
    print("*** tb_lineno:", exc.__traceback__.tb_lineno)

예제의 출력은 다음과 유사합니다:

*** print_tb:
  File "<doctest...>", line 10, in <module>
    lumberjack()
    ~~~~~~~~~~^^
*** print_exception:
Traceback (most recent call last):
  File "<doctest...>", line 10, in <module>
    lumberjack()
    ~~~~~~~~~~^^
  File "<doctest...>", line 4, in lumberjack
    bright_side_of_life()
    ~~~~~~~~~~~~~~~~~~~^^
IndexError: tuple index out of range
*** print_exc:
Traceback (most recent call last):
  File "<doctest...>", line 10, in <module>
    lumberjack()
    ~~~~~~~~~~^^
  File "<doctest...>", line 4, in lumberjack
    bright_side_of_life()
    ~~~~~~~~~~~~~~~~~~~^^
IndexError: tuple index out of range
*** format_exc, first and last line:
Traceback (most recent call last):
IndexError: tuple index out of range
*** format_exception:
['Traceback (most recent call last):\n',
 '  File "<doctest default[0]>", line 10, in <module>\n    lumberjack()\n    ~~~~~~~~~~^^\n',
 '  File "<doctest default[0]>", line 4, in lumberjack\n    bright_side_of_life()\n    ~~~~~~~~~~~~~~~~~~~^^\n',
 '  File "<doctest default[0]>", line 7, in bright_side_of_life\n    return tuple()[0]\n           ~~~~~~~^^^\n',
 'IndexError: tuple index out of range\n']
*** extract_tb:
[<FrameSummary file <doctest...>, line 10 in <module>>,
 <FrameSummary file <doctest...>, line 4 in lumberjack>,
 <FrameSummary file <doctest...>, line 7 in bright_side_of_life>]
*** format_tb:
['  File "<doctest default[0]>", line 10, in <module>\n    lumberjack()\n    ~~~~~~~~~~^^\n',
 '  File "<doctest default[0]>", line 4, in lumberjack\n    bright_side_of_life()\n    ~~~~~~~~~~~~~~~~~~~^^\n',
 '  File "<doctest default[0]>", line 7, in bright_side_of_life\n    return tuple()[0]\n           ~~~~~~~^^^\n']
*** tb_lineno: 10

다음 예제는 스택을 인쇄하고 포맷하는 다양한 방법을 보여줍니다:

>>> import traceback
>>> def another_function():
...     lumberstack()
...
>>> def lumberstack():
...     traceback.print_stack()
...     print(repr(traceback.extract_stack()))
...     print(repr(traceback.format_stack()))
...
>>> another_function()
  File "<doctest>", line 10, in <module>
    another_function()
  File "<doctest>", line 3, in another_function
    lumberstack()
  File "<doctest>", line 6, in lumberstack
    traceback.print_stack()
[('<doctest>', 10, '<module>', 'another_function()'),
 ('<doctest>', 3, 'another_function', 'lumberstack()'),
 ('<doctest>', 7, 'lumberstack', 'print(repr(traceback.extract_stack()))')]
['  File "<doctest>", line 10, in <module>\n    another_function()\n',
 '  File "<doctest>", line 3, in another_function\n    lumberstack()\n',
 '  File "<doctest>", line 8, in lumberstack\n    print(repr(traceback.format_stack()))\n']

이 마지막 예제는 마지막 몇 가지 포매팅 함수를 예시합니다:

>>> import traceback
>>> traceback.format_list([('spam.py', 3, '<module>', 'spam.eggs()'),
...                        ('eggs.py', 42, 'eggs', 'return "bacon"')])
['  File "spam.py", line 3, in <module>\n    spam.eggs()\n',
 '  File "eggs.py", line 42, in eggs\n    return "bacon"\n']
>>> an_error = IndexError('tuple index out of range')
>>> traceback.format_exception_only(an_error)
['IndexError: tuple index out of range\n']

Examples of Using TracebackException

With the helper class, we have more options:

>>> import sys
>>> from traceback import TracebackException
>>>
>>> def lumberjack():
...     bright_side_of_life()
...
>>> def bright_side_of_life():
...     t = "bright", "side", "of", "life"
...     return t[5]
...
>>> try:
...     lumberjack()
... except IndexError as e:
...     exc = e
...
>>> try:
...     try:
...         lumberjack()
...     except:
...         1/0
... except Exception as e:
...     chained_exc = e
...
>>> # limit works as with the module-level functions
>>> TracebackException.from_exception(exc, limit=-2).print()
Traceback (most recent call last):
  File "<python-input-1>", line 6, in lumberjack
    bright_side_of_life()
    ~~~~~~~~~~~~~~~~~~~^^
  File "<python-input-1>", line 10, in bright_side_of_life
    return t[5]
           ~^^^
IndexError: tuple index out of range

>>> # capture_locals adds local variables in frames
>>> TracebackException.from_exception(exc, limit=-2, capture_locals=True).print()
Traceback (most recent call last):
  File "<python-input-1>", line 6, in lumberjack
    bright_side_of_life()
    ~~~~~~~~~~~~~~~~~~~^^
  File "<python-input-1>", line 10, in bright_side_of_life
    return t[5]
           ~^^^
    t = ("bright", "side", "of", "life")
IndexError: tuple index out of range

>>> # The *chain* kwarg to print() controls whether chained
>>> # exceptions are displayed
>>> TracebackException.from_exception(chained_exc).print()
Traceback (most recent call last):
  File "<python-input-19>", line 4, in <module>
    lumberjack()
    ~~~~~~~~~~^^
  File "<python-input-8>", line 7, in lumberjack
    bright_side_of_life()
    ~~~~~~~~~~~~~~~~~~~^^
  File "<python-input-8>", line 11, in bright_side_of_life
    return t[5]
           ~^^^
IndexError: tuple index out of range

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<python-input-19>", line 6, in <module>
    1/0
    ~^~
ZeroDivisionError: division by zero

>>> TracebackException.from_exception(chained_exc).print(chain=False)
Traceback (most recent call last):
  File "<python-input-19>", line 6, in <module>
    1/0
    ~^~
ZeroDivisionError: division by zero

__future__ — Future statement definitions

소스 코드: Lib/__future__.py [https://github.com/python/cpython/tree/main/Lib/__future__.py]

Imports of the form from __future__ import feature are called future statements. These are special-cased by the Python compiler to allow the use of new Python features in modules containing the future statement before the release in which the feature becomes standard.

While these future statements are given additional special meaning by the Python compiler, they are still executed like any other import statement and the __future__ exists and is handled by the import system the same way any other Python module would be. This design serves three purposes:

임포트 문을 분석하고 임포트하는 모듈을 발견하리라고 기대하는 기존 도구가 혼동하지 않게 하려고.

호환되지 않는 변경 사항이 도입된 시점과 그것이 필수적일 때를 — 또는 이미 필수적으로 된 때를 — 문서로 만들기 위해. 이것은 실행 가능한 문서 형식이며, __future__ 를 임포트 해서 내용을 들여다봄으로써 프로그래밍 방식으로 검사 할 수 있습니다.

To ensure that future statements run under releases prior to Python 2.1 at least yield runtime exceptions (the import of __future__ will fail, because there was no module of that name prior to 2.1).

Module Contents

어떤 기능 설명도 __future__ 에서 삭제되지 않습니다. 파이썬 2.1에서 소개된 이후로 이 메커니즘을 사용하여 다음과 같은 기능이 언어에 도입되었습니다:

기능

선택적 버전

필수적 버전

효과

nested_scopes

2.1.0b1

2.2

PEP 227 [https://peps.python.org/pep-0227/]: 정적으로 중첩된 스코프

generators

2.2.0a1

2.3

PEP 255 [https://peps.python.org/pep-0255/]: 단순 제너레이터

division

2.2.0a2

3.0

PEP 238 [https://peps.python.org/pep-0238/]: 나누기 연산자 변경

absolute_import

2.5.0a1

3.0

PEP 328 [https://peps.python.org/pep-0328/]: 임포트: 복수 줄 및 절대/상대

with_statement

2.5.0a1

2.6

PEP 343 [https://peps.python.org/pep-0343/]: “with” 문

print_function

2.6.0a2

3.0

PEP 3105 [https://peps.python.org/pep-3105/]: print를 함수로 만들기

unicode_literals

2.6.0a2

3.0

PEP 3112 [https://peps.python.org/pep-3112/]: 파이썬 3000의 바이트열 리터럴

generator_stop

3.5.0b1

3.7

PEP 479 [https://peps.python.org/pep-0479/]: 제너레이터 내부의 StopIteration 처리

annotations

3.7.0b1

Never [1]

PEP 563 [https://peps.python.org/pep-0563/]: Postponed evaluation of annotations, PEP 649 [https://peps.python.org/pep-0649/]: Deferred evaluation of annotations using descriptors

class __future__._Feature

__future__.py 의 각 문장은 다음과 같은 형식입니다:

FeatureName = _Feature(OptionalRelease, MandatoryRelease,
                       CompilerFlag)

보통, OptionalRelease 는 MandatoryRelease 보다 작으며, 둘 다 sys.version_info와 같은 형태의 5-튜플입니다:

(PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int
 PY_MINOR_VERSION, # the 1; an int
 PY_MICRO_VERSION, # the 0; an int
 PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string
 PY_RELEASE_SERIAL # the 3; an int
)

_Feature.getOptionalRelease()

OptionalRelease 는 해당 기능이 승인된 첫 번째 배포를 기록합니다.

_Feature.getMandatoryRelease()

MandatoryRelease 가 아직 배포되지 않은 경우, MandatoryRelease 는 해당 기능이 언어 일부가 될 배포를 예측합니다.

그렇지 않으면 MandatoryRelease 는 기능이 언어 일부가 된 때를 기록합니다; 그 배포와 그 이후의 배포에서, 모듈이 해당 기능을 사용하기 위해 더 퓨처 문을 요구하지 않지만, 그러한 임포트는 계속 사용할 수 있습니다.

MandatoryRelease may also be None, meaning that a planned feature got dropped or that it is not yet decided.

_Feature.compiler_flag

CompilerFlag is the (bitfield) flag that should be passed in the fourth argument to the built-in function compile() to enable the feature in dynamically compiled code. This flag is stored in the _Feature.compiler_flag attribute on _Feature instances.

[1]

from __future__ import annotations was previously scheduled to become mandatory in Python 3.10, but the change was delayed and ultimately canceled. This feature will eventually be deprecated and removed. See PEP 649 [https://peps.python.org/pep-0649/] and PEP 749 [https://peps.python.org/pep-0749/].

더 보기

퓨처 문

컴파일러가 퓨처 임포트를 처리하는 방법.

PEP 236 [https://peps.python.org/pep-0236/] - Back to the __future__

The original proposal for the __future__ mechanism.

gc — Garbage Collector interface

이 모듈은 선택적인 가비지 수거기에 대한 인터페이스를 제공합니다. 수거기를 비활성화하고, 수거 빈도를 조정하며, 디버깅 옵션을 설정하는 기능을 제공합니다. 또한 수거기가 발견했지만 해제할 수 없는 도달 불가능한 객체에 대한 액세스를 제공합니다. 수거기는 파이썬에서 이미 사용된 참조 횟수 추적을 보충하므로, 프로그램이 참조 순환을 만들지 않는다고 확신한다면 수거기를 비활성화 할 수 있습니다. gc.disable()을 호출하여 자동 수거를 비활성화 할 수 있습니다. 누수가 발생하는 프로그램을 디버그하려면, gc.set_debug(gc.DEBUG_LEAK)을 호출하십시오. 이것은 gc.DEBUG_SAVEALL을 포함하므로, 가비지 수거된 객체가 검사를 위해 gc.garbage에 저장되도록 함에 유의하십시오.

gc 모듈은 다음 함수를 제공합니다:

gc.enable()

자동 가비지 수거를 활성화합니다.

gc.disable()

자동 가비지 수거를 비활성화합니다.

gc.isenabled()

자동 수거가 활성화되었으면 True를 반환합니다.

gc.collect(generation=2)

Perform a collection. The optional argument generation may be an integer specifying which generation to collect (from 0 to 2). A ValueError is raised if the generation number is invalid. The sum of collected objects and uncollectable objects is returned.

Calling gc.collect(0) will perform a GC collection on the young generation.

Calling gc.collect(1) will perform a GC collection on the young generation and an increment of the old generation.

Calling gc.collect(2) or gc.collect() performs a full collection

여러 내장형을 위해 유지되는 자유 목록(free list)은 전체 수거나 최고 세대(2)의 수거가 실행될 때마다 지워집니다. 특정 구현(특히 float)으로 인해, 일부 자유 목록에서 모든 항목이 해제되지는 않을 수 있습니다.

The effect of calling gc.collect() while the interpreter is already performing a collection is undefined.

버전 3.13에서 변경: generation=1 performs an increment of collection.

gc.set_debug(flags)

가비지 수거 디버깅 플래그를 설정합니다. 디버깅 정보가 sys.stderr에 기록됩니다. 디버깅을 제어하기 위해 비트 연산을 사용하여 결합할 수 있는 디버깅 플래그 목록은 아래를 참조하십시오.

gc.get_debug()

현재 설정된 디버깅 플래그를 반환합니다.

gc.get_objects(generation=None)

Returns a list of all objects tracked by the collector, excluding the list returned. If generation is not None, return only the objects as follows:

0: All objects in the young generation

1: No objects, as there is no generation 1 (as of Python 3.13)

2: All objects in the old generation

버전 3.8에서 변경: 새로운 generation 매개 변수.

버전 3.13에서 변경: Generation 1 is removed

인자 generation으로 감사 이벤트 gc.get_objects를 발생시킵니다.

gc.get_stats()

인터프리터가 시작된 이후의 수거 통계를 포함하는 세 개의 세대별 딕셔너리의 리스트를 반환합니다. 향후 키 수는 변경될 수 있지만, 현재 각 딕셔너리에는 다음과 같은 항목이 포함됩니다:

collections는 이 세대가 수거된 횟수입니다.

collected는 이 세대 내에서 수거된 총 객체 수입니다.

uncollectable은 이 세대 내에서 수거할 수 없는 (따라서 garbage 리스트로 이동된) 것으로 확인된 총 객체 수입니다.

Added in version 3.4.

gc.set_threshold(threshold0[, threshold1[, threshold2]])

가비지 수거 임곗값(수거 빈도)을 설정합니다. threshold0을 0으로 설정하면 수거가 비활성화됩니다.

The GC classifies objects into two generations depending on whether they have survived a collection. New objects are placed in the young generation. If an object survives a collection it is moved into the old generation.

In order to decide when to run, the collector keeps track of the number of object allocations and deallocations since the last collection. When the number of allocations minus the number of deallocations exceeds threshold0, collection starts. For each collection, all the objects in the young generation and some fraction of the old generation is collected.

The fraction of the old generation that is collected is inversely proportional to threshold1. The larger threshold1 is, the slower objects in the old generation are collected. For the default value of 10, 1% of the old generation is scanned during each collection.

threshold2 is ignored.

See Garbage collector design [https://devguide.python.org/garbage_collector] for more information.

버전 3.13에서 변경: threshold2 is ignored

gc.get_count()

현재 수거 횟수를 (count0, count1, count2)의 튜플로 반환합니다.

gc.get_threshold()

현재 수거 임곗값을 (threshold0, threshold1, threshold2)의 튜플로 반환합니다.

gc.get_referrers(*objs)

objs에 있는 것을 직접 참조하는 객체의 리스트를 반환합니다. 이 함수는 가비지 수거를 지원하는 컨테이너만 찾습니다; 다른 객체를 참조하지만, 가비지 수거를 지원하지 않는 확장형은 찾을 수 없습니다.

이미 참조 해제되었지만, 순환에 참여해서 가비지 수거기에 의해 아직 수거되지 않은 객체는 결과 참조자(referrer)에 나열될 수 있음에 유의하십시오. 현재 살아있는 객체만 가져오려면, get_referrers()를 호출하기 전에 collect()를 호출하십시오.

경고

get_referrers()에서 반환된 객체를 사용할 때는, 그중 일부는 아직 생성 중이라서 일시적으로 유효하지 않은 상태일 수 있기 때문에 주의해야 합니다. 디버깅 이외의 목적으로 get_referrers()를 사용하지 마십시오.

인자 objs로 감사 이벤트 gc.get_referrers를 발생시킵니다.

gc.get_referents(*objs)

인자로 제공된 객체가 직접 참조하는 객체의 리스트를 반환합니다. 반환된 피 참조자(referent)는 인자의 C 수준 tp_traverse 메서드(있다면)가 방문한 객체이며, 실제로 직접 도달할 수 있는 모든 객체는 아닐 수 있습니다. tp_traverse 메서드는 가비지 수거를 지원하는 객체에서만 지원되며, 순환에 참여하는 객체만 방문하면 됩니다. 그래서, 예를 들어, 인자에서 정수에 직접 도달 할 수 있으면, 해당 정수 객체가 결과 목록에 나타날 수도 그렇지 않을 수도 있습니다.

인자 objs로 감사 이벤트 gc.get_referents를 발생시킵니다.

gc.is_tracked(obj)

가비지 수거기가 객체를 현재 추적하고 있으면 True를, 그렇지 않으면 False를 반환합니다. 일반적인 규칙으로, 원자 형(atomic type)의 인스턴스는 추적하지 않고, 원자 형이 아닌 인스턴스(컨테이너, 사용자 정의 객체…)는 추적합니다. 그러나 간단한 인스턴스의 가비지 수거기 크기를 줄이기 위해 일부 형별 최적화가 존재할 수 있습니다 (예를 들어, 원자적 키와 값만 포함하는 딕셔너리):

>>> gc.is_tracked(0)
False
>>> gc.is_tracked("a")
False
>>> gc.is_tracked([])
True
>>> gc.is_tracked({})
False
>>> gc.is_tracked({"a": 1})
True

Added in version 3.1.

gc.is_finalized(obj)

주어진 객체가 가비지 수거기에 의해 파이널라이즈 되었으면 True를, 그렇지 않으면 False를 반환합니다.

>>> x = None
>>> class Lazarus:
...     def __del__(self):
...         global x
...         x = self
...
>>> lazarus = Lazarus()
>>> gc.is_finalized(lazarus)
False
>>> del lazarus
>>> gc.is_finalized(x)
True

Added in version 3.9.

gc.freeze()

Freeze all the objects tracked by the garbage collector; move them to a permanent generation and ignore them in all the future collections.

If a process will fork() without exec(), avoiding unnecessary copy-on-write in child processes will maximize memory sharing and reduce overall memory usage. This requires both avoiding creation of freed “holes” in memory pages in the parent process and ensuring that GC collections in child processes won’t touch the gc_refs counter of long-lived objects originating in the parent process. To accomplish both, call gc.disable() early in the parent process, gc.freeze() right before fork(), and gc.enable() early in child processes.

Added in version 3.7.

gc.unfreeze()

영구 세대(permanent generation)의 객체를 고정 해제하고, 가장 나이 든 세대로 되돌립니다.

Added in version 3.7.

gc.get_freeze_count()

영구 세대(permanent generation)에 있는 객체 수를 반환합니다.

Added in version 3.7.

다음 변수가 전용 액세스로 제공됩니다 (값을 변경할 수는 있지만, 다시 연결해서는 안 됩니다):

gc.garbage

수거기가 발견했지만 해제할 수 없는 도달 불가능한 객체의 리스트 (수거할 수 없는 객체). 파이썬 3.4부터, NULL이 아닌 tp_del 슬롯이 있는 C 확장형의 인스턴스를 사용할 때를 제외하고, 이 리스트는 대체로 비어 있어야 합니다.

DEBUG_SAVEALL이 설정되면, 도달할 수 없는 모든 객체가 해제되지 않고 이 목록에 추가됩니다.

버전 3.2에서 변경: 인터프리터 종료 시 이 목록이 비어 있지 않으면, ResourceWarning이 발생하는데, 기본적으로 조용(silent)합니다. DEBUG_UNCOLLECTABLE이 설정되면, 추가로 모든 수거 할 수 없는 객체가 인쇄됩니다.

버전 3.4에서 변경: Following PEP 442 [https://peps.python.org/pep-0442/], objects with a __del__() method don’t end up in gc.garbage anymore.

gc.callbacks

수거 전후에 가비지 수거기가 호출할 콜백의 리스트입니다. 콜백은 두 인자로 호출됩니다, phase와 info.

phase는 다음 두 값 중 하나일 수 있습니다:

“start”: 가비지 수거를 시작하려고 합니다.

“stop”: 가비지 수거가 완료되었습니다.

info는 콜백에 추가 정보를 제공하는 딕셔너리입니다. 현재 다음 키가 정의되어 있습니다:

“generation”: 수거되는 가장 나이 든 세대.

“collected”: phase가 “stop”일 때, 성공적으로 수거된 객체 수.

“uncollectable”: phase가 “stop”일 때, 수거할 수 없어서 garbage에 들어간 객체 수.

응용 프로그램은 이 리스트에 자체 콜백을 추가 할 수 있습니다. 주요 사용 사례는 다음과 같습니다:

다양한 세대가 수거되는 빈도와 수거에 걸린 시간과 같은 가비지 수거에 대한 통계 수집.

응용 프로그램이 자신의 수거할 수 없는 형이 garbage에 나타날 때 식별하고 지울 수 있도록 합니다.

Added in version 3.3.

set_debug()와 함께 사용하기 위해 다음 상수가 제공됩니다:

gc.DEBUG_STATS

수거 중 통계를 인쇄합니다. 이 정보는 수거 빈도를 조정할 때 유용 할 수 있습니다.

gc.DEBUG_COLLECTABLE

발견된 수거 가능한 객체에 대한 정보를 인쇄합니다.

gc.DEBUG_UNCOLLECTABLE

발견된 수거 할 수 없는 객체에 대한 정보를 인쇄합니다 (도달 할 수 있지만, 수거기가 해제할 수 없는 객체). 이 객체는 garbage 리스트에 추가됩니다.

버전 3.2에서 변경: 인터프리터 종료 시에 garbage 리스트가 비어있지 않으면 내용을 인쇄하기도 합니다.

gc.DEBUG_SAVEALL

설정하면, 발견된 모든 도달할 수 없는 객체를 해제하는 대신 garbage에 추가합니다. 누수가 있는 프로그램을 디버깅하는 데 유용 할 수 있습니다.

gc.DEBUG_LEAK

수거기가 누수가 있는 프로그램에 대한 정보를 인쇄하도록 하는 데 필요한 디버깅 플래그 (DEBUG_COLLECTABLE | DEBUG_UNCOLLECTABLE | DEBUG_SAVEALL과 같습니다).

inspect — Inspect live objects

소스 코드: Lib/inspect.py [https://github.com/python/cpython/tree/main/Lib/inspect.py]

inspect 모듈은 모듈, 클래스, 메서드, 함수, 트레이스백, 프레임 객체 및 코드 객체와 같은 라이브 객체에 대한 정보를 얻는 데 도움이 되는 몇 가지 유용한 함수를 제공합니다. 예를 들어, 클래스의 내용을 검사하거나, 메서드의 소스 코드를 꺼내오거나, 함수의 인자 리스트를 추출하고 포맷하거나, 자세한 트레이스백을 표시하는 데 필요한 모든 정보를 얻는 데 도움이 될 수 있습니다.

이 모듈은 4가지 종류의 주요 서비스를 제공합니다: 형 검사, 소스 코드 가져오기, 클래스와 함수 검사, 인터프리터 스택 검사.

형과 멤버

The getmembers() function retrieves the members of an object such as a class or module. The functions whose names begin with “is” are mainly provided as convenient choices for the second argument to getmembers(). They also help you determine when you can expect to find the following special attributes (see Import-related attributes on module objects for module attributes):

형

어트리뷰트

설명

클래스

__doc__

도큐멘테이션 문자열

__name__

이 클래스가 정의된 이름

__qualname__

정규화된 이름

__module__

이 클래스가 정의된 모듈의 이름

__type_params__

A tuple containing the type parameters of a generic class

메서드

__doc__

도큐멘테이션 문자열

__name__

이 메서드가 정의된 이름

__qualname__

정규화된 이름

__func__

메서드의 구현을 포함하는 함수 객체

__self__

이 메서드가 연결된 인스턴스, 또는 None

__module__

이 메서드가 정의된 모듈의 이름

함수

__doc__

도큐멘테이션 문자열

__name__

이 함수가 정의된 이름

__qualname__

정규화된 이름

__code__

컴파일된 함수 바이트 코드를 포함하는 코드 객체

__defaults__

위치나 키워드 매개 변수에 대한 기본값의 튜플

__kwdefaults__

키워드 전용 매개 변수의 기본값 매핑

__globals__

이 함수가 정의된 전역 이름 공간

__builtins__

builtins namespace

__annotations__

매개 변수 이름에서 어노테이션으로의 매핑; "return" 키는 반환 값 어노테이션을 위해 예약되어 있습니다.

__type_params__

A tuple containing the type parameters of a generic function

__module__

이 함수가 정의된 모듈의 이름

트레이스백

tb_frame

이 수준의 프레임 객체

tb_lasti

바이트 코드에서 마지막으로 시도한 명령의 인덱스

tb_lineno

파이썬 소스 코드의 현재 줄 번호

tb_next

(이 수준에서 호출된) 다음 내부(inner) 트레이스백 객체

프레임

f_back

다음 외부(outer) 프레임 객체 (이 프레임의 호출자)

f_builtins

이 프레임이 보는 내장 이름 공간

f_code

이 프레임에서 실행되는 코드 객체

f_globals

이 프레임이 보는 전역 이름 공간

f_lasti

바이트 코드에서 마지막으로 시도한 명령의 인덱스

f_lineno

파이썬 소스 코드의 현재 줄 번호

f_locals

이 프레임이 보는 지역 이름 공간

f_trace

이 프레임의 추적 함수(tracing function), 또는 None

f_trace_lines

indicate whether a tracing event is triggered for each source source line

f_trace_opcodes

indicate whether per-opcode events are requested

clear()

used to clear all references to local variables

코드

co_argcount

인자 개수 (키워드 전용 인자, * 또는 ** 인자는 포함하지 않습니다)

co_code

컴파일된 날 바이트 코드의 문자열

co_cellvars

(포함하는 스코프가 참조하는) 셀 변수 이름의 튜플

co_consts

바이트 코드에서 사용되는 상수의 튜플

co_filename

이 코드 객체가 만들어진 파일의 이름

co_firstlineno

파이썬 소스 코드의 첫 줄 번호

co_flags

CO_* 플래그의 비트맵, 여기를 더 읽어보십시오

co_lnotab

줄 번호에서 바이트 코드 인덱스로의 인코딩된 매핑

co_freevars

(함수의 클로저를 통해 참조되는) 자유 변수(free variables) 이름의 튜플

co_posonlyargcount

위치 전용 인자의 개수

co_kwonlyargcount

키워드 전용 인자의 개수 (** 인자는 제외합니다)

co_name

이 코드 객체가 정의된 이름

co_qualname

fully qualified name with which this code object was defined

co_names

tuple of names other than arguments and function locals

co_nlocals

지역 변수의 개수

co_stacksize

필요한 가상 기계 스택 공간

co_varnames

인자와 지역 변수 이름의 튜플

co_lines()

returns an iterator that yields successive bytecode ranges

co_positions()

returns an iterator of source code positions for each bytecode instruction

replace()

returns a copy of the code object with new values

제너레이터

__name__

이름

__qualname__

정규화된 이름

gi_frame

프레임

gi_running

제너레이터가 실행 중입니까?

gi_code

코드

gi_yieldfrom

yield from에 의해 이터레이트 중인 객체, 또는 None

async generator

__name__

이름

__qualname__

정규화된 이름

ag_await

어웨이트 중인 객체, 또는 None

ag_frame

프레임

ag_running

제너레이터가 실행 중입니까?

ag_code

코드

코루틴

__name__

이름

__qualname__

정규화된 이름

cr_await

어웨이트 중인 객체, 또는 None

cr_frame

프레임

cr_running

코루틴이 실행 중입니까?

cr_code

코드

cr_origin

코루틴이 생성된 곳, 또는 None. sys.set_coroutine_origin_tracking_depth()를 참조하세요

내장

__doc__

도큐멘테이션 문자열

__name__

이 함수나 메서드의 원래 이름

__qualname__

정규화된 이름

__self__

메서드가 연결된 인스턴스, 또는 None

버전 3.5에서 변경: __qualname__과 gi_yieldfrom 어트리뷰트를 제너레이터에 추가합니다.

제너레이터의 __name__ 어트리뷰트는 이제 코드 이름 대신 함수 이름에서 설정되며, 이제 수정할 수 있습니다.

버전 3.7에서 변경: 코루틴에 cr_origin 어트리뷰트를 추가합니다.

버전 3.10에서 변경: Add __builtins__ attribute to functions.

inspect.getmembers(object[, predicate])

이름으로 정렬된 (name, value) 쌍의 리스트로 객체(object)의 모든 멤버를 반환합니다. 각 멤버의 value 객체로 호출될 선택적 predicate 인자가 제공되면, predicate가 참값을 반환하는 멤버만 포함됩니다.

참고

getmembers() will only return class attributes defined in the metaclass when the argument is a class and those attributes have been listed in the metaclass’ custom __dir__().

inspect.getmembers_static(object[, predicate])

Return all the members of an object in a list of (name, value) pairs sorted by name without triggering dynamic lookup via the descriptor protocol, __getattr__ or __getattribute__. Optionally, only return members that satisfy a given predicate.

참고

getmembers_static() may not be able to retrieve all members that getmembers can fetch (like dynamically created attributes) and may find members that getmembers can’t (like descriptors that raise AttributeError). It can also return descriptor objects instead of instance members in some cases.

Added in version 3.11.

inspect.getmodulename(path)

감싸고 있는 패키지 이름 없이, 파일 경로(path)가 가리키는 모듈의 이름을 반환합니다. 파일 확장자는 importlib.machinery.all_suffixes()의 모든 항목에 대해 점검됩니다. 일치하면, 확장명이 제거된 최종 경로 구성 요소가 반환됩니다. 그렇지 않으면, None이 반환됩니다.

이 함수는 오직 실제 파이썬 모듈로 의미 있는 이름만 반환합니다. 잠재적으로 파이썬 패키지를 가리키는 경로는 여전히 None을 반환합니다.

버전 3.3에서 변경: 이 함수는 importlib에 직접 기반합니다.

inspect.ismodule(object)

객체가 모듈이면 True를 반환합니다.

inspect.isclass(object)

객체가 (내장이거나 파이썬 코드로 만든) 클래스이면 True를 반환합니다.

inspect.ismethod(object)

객체가 파이썬으로 작성된 연결된(bound) 메서드면 True를 반환합니다.

inspect.ispackage(object)

Return True if the object is a package.

Added in version 3.14.

inspect.isfunction(object)

객체가 파이썬 함수이면 True를 반환합니다. 람다 표현식으로 만든 함수를 포함합니다.

inspect.isgeneratorfunction(object)

객체가 파이썬 제너레이터 함수이면 True를 반환합니다.

버전 3.8에서 변경: 래핑 된 함수가 파이썬 제너레이터 함수일 때 functools.partial()로 래핑 된 함수는 이제 True를 반환합니다.

버전 3.13에서 변경: Functions wrapped in functools.partialmethod() now return True if the wrapped function is a Python generator function.

inspect.isgenerator(object)

객체가 제너레이터이면 True를 반환합니다.

inspect.iscoroutinefunction(object)

Return True if the object is a coroutine function (a function defined with an async def syntax), a functools.partial() wrapping a coroutine function, or a sync function marked with markcoroutinefunction().

Added in version 3.5.

버전 3.8에서 변경: 래핑 된 함수가 코루틴 함수일 때 functools.partial()로 래핑 된 함수는 이제 True를 반환합니다.

버전 3.12에서 변경: Sync functions marked with markcoroutinefunction() now return True.

버전 3.13에서 변경: Functions wrapped in functools.partialmethod() now return True if the wrapped function is a coroutine function.

inspect.markcoroutinefunction(func)

Decorator to mark a callable as a coroutine function if it would not otherwise be detected by iscoroutinefunction().

This may be of use for sync functions that return a coroutine, if the function is passed to an API that requires iscoroutinefunction().

When possible, using an async def function is preferred. Also acceptable is calling the function and testing the return with iscoroutine().

Added in version 3.12.

inspect.iscoroutine(object)

객체가 async def 함수가 만든 코루틴이면 True를 반환합니다.

Added in version 3.5.

inspect.isawaitable(object)

await 표현식에서 객체를 사용할 수 있으면 True를 반환합니다.

Can also be used to distinguish generator-based coroutines from regular generators:

import types

def gen():
    yield
@types.coroutine
def gen_coro():
    yield

assert not isawaitable(gen())
assert isawaitable(gen_coro())

Added in version 3.5.

inspect.isasyncgenfunction(object)

Return True if the object is an asynchronous generator function, for example:

>>> async def agen():
...     yield 1
...
>>> inspect.isasyncgenfunction(agen)
True

Added in version 3.6.

버전 3.8에서 변경: Functions wrapped in functools.partial() now return True if the wrapped function is an asynchronous generator function.

버전 3.13에서 변경: Functions wrapped in functools.partialmethod() now return True if the wrapped function is a coroutine function.

inspect.isasyncgen(object)

객체가 asynchronous generator 함수가 만든 비동기 제너레이터 이터레이터이면 True를 반환합니다.

Added in version 3.6.

inspect.istraceback(object)

객체가 트레이스백이면 True를 반환합니다.

inspect.isframe(object)

객체가 프레임이면 True를 반환합니다.

inspect.iscode(object)

객체가 코드이면 True를 반환합니다.

inspect.isbuiltin(object)

객체가 내장 함수나 연결된(bound) 내장 메서드이면 True를 반환합니다.

inspect.ismethodwrapper(object)

Return True if the type of object is a MethodWrapperType.

These are instances of MethodWrapperType, such as __str__(), __eq__() and __repr__().

Added in version 3.11.

inspect.isroutine(object)

객체가 사용자 정의이거나 내장 함수나 메서드이면 True를 반환합니다.

inspect.isabstract(object)

객체가 추상 베이스 클래스이면 True를 반환합니다.

inspect.ismethoddescriptor(object)

객체가 메서드 디스크립터이면 True를 반환하지만, ismethod(), isclass(), isfunction() 또는 isbuiltin()이 참일 때는 그렇지 않습니다.

This, for example, is true of int.__add__. An object passing this test has a __get__() method, but not a __set__() method or a __delete__() method. Beyond that, the set of attributes varies. A __name__ attribute is usually sensible, and __doc__ often is.

Methods implemented via descriptors that also pass one of the other tests return False from the ismethoddescriptor() test, simply because the other tests promise more – you can, e.g., count on having the __func__ attribute (etc) when an object passes ismethod().

버전 3.13에서 변경: This function no longer incorrectly reports objects with __get__() and __delete__(), but not __set__(), as being method descriptors (such objects are data descriptors, not method descriptors).

inspect.isdatadescriptor(object)

객체가 데이터 디스크립터이면 True를 반환합니다.

Data descriptors have a __set__ or a __delete__ method. Examples are properties (defined in Python), getsets, and members. The latter two are defined in C and there are more specific tests available for those types, which is robust across Python implementations. Typically, data descriptors will also have __name__ and __doc__ attributes (properties, getsets, and members have both of these attributes), but this is not guaranteed.

inspect.isgetsetdescriptor(object)

객체가 getset 디스크립터이면 True를 반환합니다.

CPython 구현 상세: getset은 PyGetSetDef 구조체를 통해 확장 모듈에서 정의된 어트리뷰트입니다. 이러한 형이 없는 파이썬 구현에서, 이 메서드는 항상 False를 반환합니다.

inspect.ismemberdescriptor(object)

객체가 멤버 디스크립터이면 True를 반환합니다.

CPython 구현 상세: 멤버 디스크립터는 PyMemberDef 구조체를 통해 확장 모듈에서 정의된 어트리뷰트입니다. 이러한 형이 없는 파이썬 구현에서, 이 메서드는 항상 False를 반환합니다.

소스 코드 가져오기

inspect.getdoc(object)

Get the documentation string for an object, cleaned up with cleandoc(). If the documentation string for an object is not provided and the object is a class, a method, a property or a descriptor, retrieve the documentation string from the inheritance hierarchy. Return None if the documentation string is invalid or missing.

버전 3.5에서 변경: 이제 재정의되지 않으면 독스트링이 상속됩니다.

inspect.getcomments(object)

객체의 소스 코드 바로 앞(클래스, 함수 또는 메서드일 때)이나 파이썬 소스 파일의 최상단 (객체가 모듈일 때) 주석 줄들을 단일 문자열로 반환합니다. 객체의 소스 코드를 사용할 수 없으면, None을 반환합니다. 객체가 C나 대화식 셸에서 정의될 때 이런 일이 일어날 수 있습니다.

inspect.getfile(object)

객체가 정의된 (텍스트나 바이너리) 파일의 이름을 반환합니다. 객체가 내장 모듈, 클래스 또는 함수이면 TypeError로 실패합니다.

inspect.getmodule(object)

Try to guess which module an object was defined in. Return None if the module cannot be determined.

inspect.getsourcefile(object)

Return the name of the Python source file in which an object was defined or None if no way can be identified to get the source. This will fail with a TypeError if the object is a built-in module, class, or function.

inspect.getsourcelines(object)

Return a list of source lines and starting line number for an object. The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a list of the lines corresponding to the object and the line number indicates where in the original source file the first line of code was found. An OSError is raised if the source code cannot be retrieved. A TypeError is raised if the object is a built-in module, class, or function.

버전 3.3에서 변경: IOError 대신 OSError가 발생합니다. 이제 IOError는 OSError의 별칭입니다.

inspect.getsource(object)

Return the text of the source code for an object. The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a single string. An OSError is raised if the source code cannot be retrieved. A TypeError is raised if the object is a built-in module, class, or function.

버전 3.3에서 변경: IOError 대신 OSError가 발생합니다. 이제 IOError는 OSError의 별칭입니다.

inspect.cleandoc(doc)

코드 블록과 일치하도록 들여쓰기 된 독스트링에서 들여쓰기를 정리합니다.

모든 선행 공백이 첫 번째 줄에서 제거됩니다. 두 번째 줄부터 균일하게 제거할 수 있는 선행 공백이 제거됩니다. 시작과 끝의 빈 줄은 그다음에 제거됩니다. 또한, 모든 탭이 스페이스로 확장됩니다.

Signature 객체로 콜러블 검사하기

Added in version 3.3.

The Signature object represents the call signature of a callable object and its return annotation. To retrieve a Signature object, use the signature() function.

inspect.signature(callable, *, follow_wrapped=True, globals=None, locals=None, eval_str=False, annotation_format=Format.VALUE)

Return a Signature object for the given callable:

>>> from inspect import signature
>>> def foo(a, *, b:int, **kwargs):
...     pass

>>> sig = signature(foo)

>>> str(sig)
'(a, *, b: int, **kwargs)'

>>> str(sig.parameters['b'])
'b: int'

>>> sig.parameters['b'].annotation
<class 'int'>

일반 함수와 클래스에서 functools.partial() 객체에 이르기까지 광범위한 파이썬 콜러블을 받아들입니다.

If some of the annotations are strings (e.g., because from __future__ import annotations was used), signature() will attempt to automatically un-stringize the annotations using annotationlib.get_annotations(). The globals, locals, and eval_str parameters are passed into annotationlib.get_annotations() when resolving the annotations; see the documentation for annotationlib.get_annotations() for instructions on how to use these parameters. A member of the annotationlib.Format enum can be passed to the annotation_format parameter to control the format of the returned annotations. For example, use annotation_format=annotationlib.Format.STRING to return annotations in string format.

Raises ValueError if no signature can be provided, and TypeError if that type of object is not supported. Also, if the annotations are stringized, and eval_str is not false, the eval() call(s) to un-stringize the annotations in annotationlib.get_annotations() could potentially raise any kind of exception.

A slash (/) in the signature of a function denotes that the parameters prior to it are positional-only. For more info, see the FAQ entry on positional-only parameters.

버전 3.5에서 변경: The follow_wrapped parameter was added. Pass False to get a signature of callable specifically (callable.__wrapped__ will not be used to unwrap decorated callables.)

버전 3.10에서 변경: The globals, locals, and eval_str parameters were added.

버전 3.14에서 변경: The annotation_format parameter was added.

참고

특정 파이썬 구현에서 일부 콜러블은 검사할 수 없습니다. 예를 들어, CPython에서, C로 정의된 일부 내장 함수는 인자에 대한 메타 데이터를 제공하지 않습니다.

CPython 구현 상세: If the passed object has a __signature__ attribute, we may use it to create the signature. The exact semantics are an implementation detail and are subject to unannounced changes. Consult the source code for current semantics.

class inspect.Signature(parameters=None, *, return_annotation=Signature.empty)

A Signature object represents the call signature of a function and its return annotation. For each parameter accepted by the function it stores a Parameter object in its parameters collection.

선택적 parameters 인자는 Parameter 객체의 시퀀스이며, 중복된 이름을 가진 매개 변수가 없는지, 매개 변수가 올바른 순서인지 (즉, 위치 전용이 먼저 온 후, 위치-키워드가 그다음에 오는지), 기본값이 있는 매개 변수가 그렇지 않은 매개 변수 뒤에 오는지 검사합니다.

The optional return_annotation argument can be an arbitrary Python object. It represents the “return” annotation of the callable.

Signature objects are immutable. Use Signature.replace() or copy.replace() to make a modified copy.

버전 3.5에서 변경: Signature objects are now picklable and hashable.

empty

반환 값 어노테이션이 없음을 지정하는 특수 클래스 수준 마커입니다.

parameters

매개 변수 이름에서 해당 Parameter 객체로의 순서 있는 매핑. 키워드 전용 매개 변수를 포함하여, 매개 변수는 엄격한 정의 순서대로 나타납니다.

버전 3.7에서 변경: 실제로 파이썬 3에서 항상 유지되었습니다만, 파이썬은 버전 3.7부터 키워드 전용 매개 변수의 선언 순서를 유지한다는 것을 명시적으로 보장합니다.

return_annotation

콜러블의 “반환 값” 어노테이션. 콜러블에 “반환 값” 어노테이션이 없으면, 이 어트리뷰트는 Signature.empty로 설정됩니다.

bind(*args, **kwargs)

위치와 키워드 인자에서 매개 변수로의 매핑을 만듭니다. *args와 **kwargs가 서명과 일치하면 BoundArguments를 반환하고, 그렇지 않으면 TypeError를 발생시킵니다.

bind_partial(*args, **kwargs)

Signature.bind()와 같은 방식으로 작동하지만, 일부 필수 인자를 생략 할 수 있습니다 (functools.partial() 동작을 흉내 냅니다). BoundArguments를 반환하거나, 전달된 인자가 서명과 일치하지 않으면 TypeError를 발생시킵니다.

replace(*[, parameters][, return_annotation])

Create a new Signature instance based on the instance replace() was invoked on. It is possible to pass different parameters and/or return_annotation to override the corresponding properties of the base signature. To remove return_annotation from the copied Signature, pass in Signature.empty.

>>> def test(a, b):
...     pass
...
>>> sig = signature(test)
>>> new_sig = sig.replace(return_annotation="new return anno")
>>> str(new_sig)
"(a, b) -> 'new return anno'"

Signature objects are also supported by the generic function copy.replace().

format(*, max_width=None, quote_annotation_strings=True)

Create a string representation of the Signature object.

If max_width is passed, the method will attempt to fit the signature into lines of at most max_width characters. If the signature is longer than max_width, all parameters will be on separate lines.

If quote_annotation_strings is False, annotations in the signature are displayed without opening and closing quotation marks if they are strings. This is useful if the signature was created with the STRING format or if from __future__ import annotations was used.

Added in version 3.13.

버전 3.14에서 변경: The unquote_annotations parameter was added.

classmethod from_callable(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False)

Return a Signature (or its subclass) object for a given callable obj.

This method simplifies subclassing of Signature:

class MySignature(Signature):
    pass
sig = MySignature.from_callable(sum)
assert isinstance(sig, MySignature)

Its behavior is otherwise identical to that of signature().

Added in version 3.5.

버전 3.10에서 변경: The globals, locals, and eval_str parameters were added.

class inspect.Parameter(name, kind, *, default=Parameter.empty, annotation=Parameter.empty)

Parameter objects are immutable. Instead of modifying a Parameter object, you can use Parameter.replace() or copy.replace() to create a modified copy.

버전 3.5에서 변경: Parameter objects are now picklable and hashable.

empty

기본값과 어노테이션이 없음을 지정하는 특수 클래스 수준 마커.

name

문자열로 표현한 매개 변수의 이름. 이름은 유효한 파이썬 식별자여야 합니다.

CPython 구현 상세: CPython은 컴프리헨션과 제너레이터 표현식을 구현하는 데 사용되는 코드 객체에서 .0 형식의 묵시적 매개 변수 이름을 생성합니다.

버전 3.6에서 변경: These parameter names are now exposed by this module as names like implicit0.

default

매개 변수의 기본값. 매개 변수에 기본값이 없으면, 이 어트리뷰트는 Parameter.empty로 설정됩니다.

annotation

매개 변수의 어노테이션. 매개 변수에 어노테이션이 없으면, 이 어트리뷰트는 Parameter.empty로 설정됩니다.

kind

Describes how argument values are bound to the parameter. The possible values are accessible via Parameter (like Parameter.KEYWORD_ONLY), and support comparison and ordering, in the following order:

이름

의미

POSITIONAL_ONLY

위치 인자로만 값을 제공해야 합니다. 위치 전용 매개 변수는 파이썬 함수 정의에서 / 항목 (있다면) 앞에 나오는 매개 변수입니다.

POSITIONAL_OR_KEYWORD

값은 키워드나 위치 인자로 제공될 수 있습니다 (이것이 파이썬으로 구현된 함수의 표준 연결 동작입니다).

VAR_POSITIONAL

다른 매개 변수에 연결되지 않은 위치 인자의 튜플. 이것은 파이썬 함수 정의의 *args 매개 변수에 해당합니다.

KEYWORD_ONLY

키워드 인자로만 값을 제공해야 합니다. 키워드 전용 매개 변수는 파이썬 함수 정의에서 *나 *args 항목 다음에 나오는 매개 변수입니다.

VAR_KEYWORD

다른 매개 변수에 연결되지 않은 키워드 인자의 딕셔너리. 이것은 파이썬 함수 정의의 **kwargs 매개 변수에 해당합니다.

Example: print all keyword-only arguments without default values:

>>> def foo(a, b, *, c, d=10):
...     pass

>>> sig = signature(foo)
>>> for param in sig.parameters.values():
...     if (param.kind == param.KEYWORD_ONLY and
...                        param.default is param.empty):
...         print('Parameter:', param)
Parameter: c

kind.description

Describes an enum value of Parameter.kind.

Added in version 3.8.

Example: print all descriptions of arguments:

>>> def foo(a, b, *, c, d=10):
...     pass

>>> sig = signature(foo)
>>> for param in sig.parameters.values():
...     print(param.kind.description)
positional or keyword
positional or keyword
keyword-only
keyword-only

replace(*[, name][, kind][, default][, annotation])

Create a new Parameter instance based on the instance replaced was invoked on. To override a Parameter attribute, pass the corresponding argument. To remove a default value or/and an annotation from a Parameter, pass Parameter.empty.

>>> from inspect import Parameter
>>> param = Parameter('foo', Parameter.KEYWORD_ONLY, default=42)
>>> str(param)
'foo=42'

>>> str(param.replace()) # Will create a shallow copy of 'param'
'foo=42'

>>> str(param.replace(default=Parameter.empty, annotation='spam'))
"foo: 'spam'"

Parameter objects are also supported by the generic function copy.replace().

버전 3.4에서 변경: In Python 3.3 Parameter objects were allowed to have name set to None if their kind was set to POSITIONAL_ONLY. This is no longer permitted.

class inspect.BoundArguments

Signature.bind()나 Signature.bind_partial() 호출의 결과. 인자에서 함수의 매개 변수로의 매핑을 보관합니다.

arguments

매개 변수 이름에서 인자 값으로의 가변 매핑. 명시적으로 연결된 인자만 포함합니다. arguments의 변경 사항은 args와 kwargs에 반영됩니다.

인자 처리 목적으로 Signature.parameters와 함께 사용해야 합니다.

참고

Signature.bind()나 Signature.bind_partial()이 기본값에 의존하는 인자는 건너뜁니다. 그러나, 필요하다면 BoundArguments.apply_defaults()를 사용하여 추가하십시오.

버전 3.9에서 변경: arguments는 이제 dict 형입니다. 이전에는, collections.OrderedDict 형이었습니다.

args

위치 인자 값의 튜플. arguments 어트리뷰트에서 동적으로 계산됩니다.

kwargs

A dict of keyword arguments values. Dynamically computed from the arguments attribute. Arguments that can be passed positionally are included in args instead.

signature

부모 Signature 객체에 대한 참조.

apply_defaults()

누락된 인자에 대한 기본값을 설정합니다.

가변 위치 인자(*args)의 기본값은 빈 튜플입니다.

가변 변수 키워드 인자(**kwargs)의 기본값은 빈 딕셔너리입니다.

>>> def foo(a, b='ham', *args): pass
>>> ba = inspect.signature(foo).bind('spam')
>>> ba.apply_defaults()
>>> ba.arguments
{'a': 'spam', 'b': 'ham', 'args': ()}

Added in version 3.5.

The args and kwargs properties can be used to invoke functions:

def test(a, *, b):
    ...

sig = signature(test)
ba = sig.bind(10, b=20)
test(*ba.args, **ba.kwargs)

더 보기

PEP 362 [https://peps.python.org/pep-0362/] - 함수 Signature 객체.

자세한 명세, 구현 세부 사항 및 예

클래스와 함수

inspect.getclasstree(classes, unique=False)

주어진 클래스 리스트를 중첩된 리스트의 계층 구조로 배치합니다. 중첩된 리스트가 나타나면, 리스트 바로 앞에 나오는 항목의 클래스에서 파생된 클래스를 포함합니다. 각 항목은 클래스와 베이스 클래스의 튜플을 포함하는 2-튜플입니다. unique 인자가 참이면, 주어진 리스트의 각 클래스가 반환된 구조에 정확히 하나의 항목으로 나타납니다. 그렇지 않으면, 다중 상속을 사용하는 클래스와 그 자식들이 여러 번 나타납니다.

inspect.getfullargspec(func)

파이썬 함수 매개 변수의 이름과 기본값을 가져옵니다. 네임드 튜플이 반환됩니다:

FullArgSpec(args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations)

args는 위치 매개 변수 이름의 리스트입니다. varargs는 * 매개 변수의 이름이거나 임의의 위치 인자가 허용되지 않으면 None입니다. varkw는 ** 매개 변수의 이름이거나 임의의 키워드 인자가 허용되지 않으면 None입니다. defaults는 마지막 n 개의 위치 매개 변수에 해당하는 기본 인자 값의 n-튜플이거나, 이러한 기본값이 정의되지 않으면 None입니다. kwonlyargs는 선언 순서를 따르는 키워드 전용 매개 변수 이름 리스트입니다. kwonlydefaults는 kwonlyargs의 매개 변수 이름에서 인자가 제공되지 않을 때 사용되는 기본값으로의 딕셔너리 매핑입니다. annotations는 매개 변수 이름에서 어노테이션으로의 딕셔너리 매핑입니다. 특수키 "return"은 함수 반환 값 어노테이션(있다면)을 보고하는 데 사용됩니다.

signature()와 Signature 객체가 콜러블 내부 검사에 권장되는 API를 제공하고, 확장 모듈 API에서 종종 등장하는 추가 동작(위치 전용 인자와 같은)을 지원함에 유의하십시오. 이 함수는 주로 파이썬 2 inspect 모듈 API와의 호환성을 유지해야 하는 코드에서 사용하기 위해 유지됩니다.

버전 3.4에서 변경: 이 함수는 이제 signature()를 기반으로 하지만, 여전히 __wrapped__ 어트리뷰트를 무시하고 연결된(bound) 메서드의 서명 출력에 이미 연결된 첫 번째 매개 변수를 포함합니다.

버전 3.6에서 변경: 이 메서드는 이전에 파이썬 3.5에서 signature()로 대신하면서 폐지된 것으로 문서화되었지만, 레거시 getargspec() API에서 마이그레이션 하는 단일 소스 파이썬 2/3 코드를 위한 명확하게 지원되는 표준 인터페이스를 복원하기 위해 이 결정을 번복했습니다.

버전 3.7에서 변경: 실제로 파이썬 3에서 항상 유지되었습니다만, 파이썬은 버전 3.7부터 키워드 전용 매개 변수의 선언 순서를 유지한다는 것을 명시적으로 보장합니다.

inspect.getargvalues(frame)

특정 프레임으로 전달된 인자에 대한 정보를 얻습니다. 네임드 튜플 ArgInfo(args, varargs, keywords, locals)가 반환됩니다. args는 인자 이름의 리스트입니다. varargs와 keywords는 *와 ** 인자의 이름이거나 None입니다. locals는 주어진 프레임의 지역 딕셔너리입니다.

참고

이 함수는 실수로 파이썬 3.5에서 폐지된 것으로 표시되었습니다.

inspect.formatargvalues(args[, varargs, varkw, locals, formatarg, formatvarargs, formatvarkw, formatvalue])

getargvalues()가 반환한 4개의 값으로 예쁜 인자 명세를 포맷합니다. format* 인자는 해당 이름과 값을 문자열로 변환하기 위해 호출되는 선택적 포매팅 함수입니다.

참고

이 함수는 실수로 파이썬 3.5에서 폐지된 것으로 표시되었습니다.

inspect.getmro(cls)

클래스 cls의 베이스 클래스의 튜플(cls를 포함합니다)을 메서드 결정 순서로 반환합니다. 이 튜플에는 클래스가 두 번 이상 나타나지 않습니다. 메서드 결정 순서는 cls의 형에 따라 다릅니다. 매우 독특한 사용자 정의 메타 형을 사용하지 않는 한, cls는 튜플의 첫 번째 요소가 됩니다.

inspect.getcallargs(func, /, *args, **kwds)

Bind the args and kwds to the argument names of the Python function or method func, as if it was called with them. For bound methods, bind also the first argument (typically named self) to the associated instance. A dict is returned, mapping the argument names (including the names of the * and ** arguments, if any) to their values from args and kwds. In case of invoking func incorrectly, i.e. whenever func(*args, **kwds) would raise an exception because of incompatible signature, an exception of the same type and the same or similar message is raised. For example:

>>> from inspect import getcallargs
>>> def f(a, b=1, *pos, **named):
...     pass
...
>>> getcallargs(f, 1, 2, 3) == {'a': 1, 'named': {}, 'b': 2, 'pos': (3,)}
True
>>> getcallargs(f, a=2, x=4) == {'a': 2, 'named': {'x': 4}, 'b': 1, 'pos': ()}
True
>>> getcallargs(f)
Traceback (most recent call last):
...
TypeError: f() missing 1 required positional argument: 'a'

Added in version 3.2.

버전 3.5부터 폐지됨: 대신 Signature.bind()와 Signature.bind_partial()을 사용하십시오.

inspect.getclosurevars(func)

파이썬 함수나 메서드 func에 있는 외부 이름 참조에서 현재 값으로의 매핑을 얻습니다. 네임드 튜플 ClosureVars(nonlocals, globals, builtins, unbound)가 반환됩니다. nonlocals는 참조된 이름을 어휘 클로저(closure) 변수로, globals는 함수의 모듈 전역으로, builtins는 함수 바디에서 볼 수 있는 내장으로 매핑합니다. unbound는 현재 모듈 전역과 내장에서 전혀 결정할 수 없는 함수에서 참조된 이름 집합입니다.

func가 파이썬 함수나 메서드가 아니면 TypeError가 발생합니다.

Added in version 3.3.

inspect.unwrap(func, *, stop=None)

func로 래핑 된 객체를 가져옵니다. 체인의 마지막 객체를 반환하는 __wrapped__ 어트리뷰트의 체인을 따라갑니다.

stop은 래퍼 체인의 객체를 유일한 인자로 받아들이는 선택적 콜백으로, 콜백이 참값을 반환할 때 언 래핑을 조기에 종료 할 수 있도록 합니다. 콜백이 참값을 반환하지 않으면, 체인의 마지막 객체가 평소처럼 반환됩니다. 예를 들어, signature()는 이것을 사용하여 체인에 있는 객체에 __signature__ 어트리뷰트가 정의되면 언 래핑을 중지합니다.

순환이 발견되면 ValueError가 발생합니다.

Added in version 3.4.

inspect.get_annotations(obj, *, globals=None, locals=None, eval_str=False, format=annotationlib.Format.VALUE)

Compute the annotations dict for an object.

This is an alias for annotationlib.get_annotations(); see the documentation of that function for more information.

Added in version 3.10.

버전 3.14에서 변경: This function is now an alias for annotationlib.get_annotations(). Calling it as inspect.get_annotations will continue to work.

인터프리터 스택

Some of the following functions return FrameInfo objects. For backwards compatibility these objects allow tuple-like operations on all attributes except positions. This behavior is considered deprecated and may be removed in the future.

class inspect.FrameInfo

frame

The frame object that the record corresponds to.

filename

The file name associated with the code being executed by the frame this record corresponds to.

lineno

The line number of the current line associated with the code being executed by the frame this record corresponds to.

function

The function name that is being executed by the frame this record corresponds to.

code_context

A list of lines of context from the source code that’s being executed by the frame this record corresponds to.

index

The index of the current line being executed in the code_context list.

positions

A dis.Positions object containing the start line number, end line number, start column offset, and end column offset associated with the instruction being executed by the frame this record corresponds to.

버전 3.5에서 변경: Return a named tuple instead of a tuple.

버전 3.11에서 변경: FrameInfo is now a class instance (that is backwards compatible with the previous named tuple).

class inspect.Traceback

filename

The file name associated with the code being executed by the frame this traceback corresponds to.

lineno

The line number of the current line associated with the code being executed by the frame this traceback corresponds to.

function

The function name that is being executed by the frame this traceback corresponds to.

code_context

A list of lines of context from the source code that’s being executed by the frame this traceback corresponds to.

index

The index of the current line being executed in the code_context list.

positions

A dis.Positions object containing the start line number, end line number, start column offset, and end column offset associated with the instruction being executed by the frame this traceback corresponds to.

버전 3.11에서 변경: Traceback is now a class instance (that is backwards compatible with the previous named tuple).

참고

이러한 함수가 반환하는 프레임 레코드의 첫 번째 요소에서 발견되는 것처럼, 프레임 객체에 대한 참조를 유지하면 프로그램이 참조 순환을 만들 수 있습니다. 일단 참조 순환이 생성되면, 파이썬의 선택적 순환 검출기가 활성화되어 있어도, 순환을 형성하는 객체에서 액세스 할 수 있는 모든 객체의 수명이 훨씬 더 길어질 수 있습니다. 이러한 순환을 만들어야만 하면, 명시적으로 끊어서 객체의 지연된 파괴와 메모리 소비 증가를 피하는 것이 중요합니다.

순환 감지기가 이를 잡기는 하겠지만, finally 절에서 순환을 제거하여 프레임(과 지역 변수)의 파괴를 결정적(deterministic)으로 만들 수 있습니다. 파이썬을 컴파일할 때나 gc.disable()을 사용해서 순환 감지기를 비활성화했을 때도 중요합니다. 예를 들면:

def handle_stackframe_without_leak():
    frame = inspect.currentframe()
    try:
        # do something with the frame
    finally:
        del frame

프레임을 계속 유지하려면 (예를 들어 나중에 트레이스백을 인쇄하려고) frame.clear() 메서드를 사용하여 참조 순환을 끊을 수도 있습니다.

이 함수들 대부분이 지원하는 선택적 context 인자는 반환할 문맥(context) 줄 수를 지정합니다. 이 줄들은 현재 줄을 중심으로 합니다.

inspect.getframeinfo(frame, context=1)

Get information about a frame or traceback object. A Traceback object is returned.

버전 3.11에서 변경: A Traceback object is returned instead of a named tuple.

inspect.getouterframes(frame, context=1)

Get a list of FrameInfo objects for a frame and all outer frames. These frames represent the calls that lead to the creation of frame. The first entry in the returned list represents frame; the last entry represents the outermost call on frame’s stack.

버전 3.5에서 변경: 네임드 튜플 FrameInfo(frame, filename, lineno, function, code_context, index)의 리스트가 반환됩니다.

버전 3.11에서 변경: A list of FrameInfo objects is returned.

inspect.getinnerframes(traceback, context=1)

Get a list of FrameInfo objects for a traceback’s frame and all inner frames. These frames represent calls made as a consequence of frame. The first entry in the list represents traceback; the last entry represents where the exception was raised.

버전 3.5에서 변경: 네임드 튜플 FrameInfo(frame, filename, lineno, function, code_context, index)의 리스트가 반환됩니다.

버전 3.11에서 변경: A list of FrameInfo objects is returned.

inspect.currentframe()

호출자의 스택 프레임에 대한 프레임 객체를 반환합니다.

CPython 구현 상세: 이 함수는 인터프리터의 파이썬 스택 프레임 지원에 의존하며, 모든 파이썬 구현에서 제공된다고 보장되는 것은 아닙니다. 파이썬 스택 프레임 지원이 없는 구현에서 실행하면, 이 함수는 None을 반환합니다.

inspect.stack(context=1)

Return a list of FrameInfo objects for the caller’s stack. The first entry in the returned list represents the caller; the last entry represents the outermost call on the stack.

버전 3.5에서 변경: 네임드 튜플 FrameInfo(frame, filename, lineno, function, code_context, index)의 리스트가 반환됩니다.

버전 3.11에서 변경: A list of FrameInfo objects is returned.

inspect.trace(context=1)

Return a list of FrameInfo objects for the stack between the current frame and the frame in which an exception currently being handled was raised in. The first entry in the list represents the caller; the last entry represents where the exception was raised.

버전 3.5에서 변경: 네임드 튜플 FrameInfo(frame, filename, lineno, function, code_context, index)의 리스트가 반환됩니다.

버전 3.11에서 변경: A list of FrameInfo objects is returned.

정적으로 어트리뷰트 가져오기

Both getattr() and hasattr() can trigger code execution when fetching or checking for the existence of attributes. Descriptors, like properties, will be invoked and __getattr__() and __getattribute__() may be called.

문서화 도구처럼 수동적인(passive) 검사를 원할 때는 불편할 수 있습니다. getattr_static()은 getattr()과 같은 서명을 갖지만 어트리뷰트를 가져올 때 코드 실행을 피합니다.

inspect.getattr_static(obj, attr, default=None)

Retrieve attributes without triggering dynamic lookup via the descriptor protocol, __getattr__() or __getattribute__().

참고: 이 함수는 getattr이 가져올 수 있는 모든 어트리뷰트를 조회하지 못할 수 있으며 (가령 동적으로 만들어진 어트리뷰트), getattr이 가져올 수 없는 어트리뷰트를 찾을 수 있습니다 (가령 AttributeError를 발생시키는 디스크립터). 또한 인스턴스 멤버 대신 디스크립터 객체를 반환할 수도 있습니다.

인스턴스 __dict__가 다른 멤버(예를 들어 프로퍼티)에 의해 가려지면 이 함수는 인스턴스 멤버를 찾을 수 없습니다.

Added in version 3.2.

getattr_static()은 디스크립터를 해석하지 않습니다, 예를 들어 C로 구현된 객체의 슬롯 디스크립터나 getset 디스크립터. 하부 어트리뷰트 대신 디스크립터 객체가 반환됩니다.

다음과 같은 코드로 이를 처리할 수 있습니다. 임의의 getset 디스크립터에 대해 이를 호출하면 코드 실행이 유발될 수 있음에 유의하십시오:

# example code for resolving the builtin descriptor types
class _foo:
    __slots__ = ['foo']

slot_descriptor = type(_foo.foo)
getset_descriptor = type(type(open(__file__)).name)
wrapper_descriptor = type(str.__dict__['__add__'])
descriptor_types = (slot_descriptor, getset_descriptor, wrapper_descriptor)

result = getattr_static(some_object, 'foo')
if type(result) in descriptor_types:
    try:
        result = result.__get__()
    except AttributeError:
        # descriptors can raise AttributeError to
        # indicate there is no underlying value
        # in which case the descriptor itself will
        # have to do
        pass

Current State of Generators, Coroutines, and Asynchronous Generators

코루틴 스케줄러를 구현할 때와 기타 제너레이터의 고급 사용을 위해, 제너레이터가 현재 실행 중인지, 시작, 재개 또는 실행을 대기하는 중인지, 또는 이미 종료되었는지를 판별하는 것이 유용합니다. getgeneratorstate()를 사용하면 제너레이터의 현재 상태를 쉽게 확인할 수 있습니다.

inspect.getgeneratorstate(generator)

제너레이터-이터레이터의 현재 상태를 가져옵니다.

가능한 상태는 다음과 같습니다:

GEN_CREATED: 실행 시작을 기다리는 중입니다.

GEN_RUNNING: 현재 인터프리터에서 실행 중입니다.

GEN_SUSPENDED: 현재 일드(yield) 표현식에서 일시 중지되었습니다.

GEN_CLOSED: 실행이 완료되었습니다.

Added in version 3.2.

inspect.getcoroutinestate(coroutine)

코루틴 객체의 현재 상태를 가져옵니다. 이 함수는 async def 함수가 만든 코루틴 객체와 함께 사용하기 위한 것이지만, cr_running과 cr_frame 어트리뷰트가 있는 임의의 코루틴류 객체를 허용합니다.

가능한 상태는 다음과 같습니다:

CORO_CREATED: 실행 시작을 기다리는 중입니다.

CORO_RUNNING: 현재 인터프리터에서 실행 중입니다.

CORO_SUSPENDED: 현재 어웨이트(await) 표현식에서 일시 중지되었습니다.

CORO_CLOSED: 실행이 완료되었습니다.

Added in version 3.5.

inspect.getasyncgenstate(agen)

Get current state of an asynchronous generator object. The function is intended to be used with asynchronous iterator objects created by async def functions which use the yield statement, but will accept any asynchronous generator-like object that has ag_running and ag_frame attributes.

가능한 상태는 다음과 같습니다:

AGEN_CREATED: Waiting to start execution.

AGEN_RUNNING: Currently being executed by the interpreter.

AGEN_SUSPENDED: Currently suspended at a yield expression.

AGEN_CLOSED: Execution has completed.

Added in version 3.12.

제너레이터의 현재 내부 상태도 조회할 수 있습니다. 이는 주로 내부 상태가 예상대로 갱신되었는지 확인하는 테스트 목적으로 유용합니다:

inspect.getgeneratorlocals(generator)

generator의 라이브 로컬 변수에서 그것의 현재 값으로의 매핑을 얻습니다. 변수 이름을 값으로 매핑하는 딕셔너리가 반환됩니다. 이것은 제너레이터 바디에서 locals()를 호출하는 것과 동등하며, 같은 경고가 모두 적용됩니다.

generator가 현재 연결된 프레임이 없는 제너레이터이면, 빈 딕셔너리가 반환됩니다. generator가 파이썬 제너레이터 객체가 아니면 TypeError가 발생합니다.

CPython 구현 상세: 이 함수는 내부 검사를 위해 파이썬 스택 프레임을 노출하는 제너레이터에 의존하며, 모든 파이썬 구현에서 보장되는 것은 아닙니다. 그럴 경우, 이 함수는 항상 빈 딕셔너리를 반환합니다.

Added in version 3.3.

inspect.getcoroutinelocals(coroutine)

이 함수는 getgeneratorlocals()와 유사하지만, async def 함수가 만든 코루틴 객체에 작동합니다.

Added in version 3.5.

inspect.getasyncgenlocals(agen)

This function is analogous to getgeneratorlocals(), but works for asynchronous generator objects created by async def functions which use the yield statement.

Added in version 3.12.

코드 객체 비트 플래그

Python code objects have a co_flags attribute, which is a bitmap of the following flags:

inspect.CO_OPTIMIZED

코드 객체는 빠른 locals(fast locals)를 사용하여 최적화되었습니다.

inspect.CO_NEWLOCALS

If set, a new dict will be created for the frame’s f_locals when the code object is executed.

inspect.CO_VARARGS

코드 객체에는 (*args 같은) 가변 위치 매개 변수가 있습니다.

inspect.CO_VARKEYWORDS

코드 객체에는 (**kwargs 같은) 가변 키워드 매개 변수가 있습니다.

inspect.CO_NESTED

코드 객체가 중첩 함수일 때 이 플래그가 설정됩니다.

inspect.CO_GENERATOR

코드 객체가 제너레이터 함수일 때, 즉 코드 객체가 실행될 때 제너레이터 객체를 반환할 때 이 플래그가 설정됩니다.

inspect.CO_COROUTINE

코드 객체가 코루틴 함수일 때 이 플래그가 설정됩니다. 코드 객체가 실행될 때 코루틴 객체를 반환합니다. 자세한 내용은 PEP 492 [https://peps.python.org/pep-0492/]를 참조하십시오.

Added in version 3.5.

inspect.CO_ITERABLE_COROUTINE

이 플래그는 제너레이터를 제너레이터 기반 코루틴으로 변환하는 데 사용됩니다. 이 플래그가 있는 제너레이터 객체는 await 표현식에 사용될 수 있으며, 코루틴 객체를 yield from 할 수 있습니다. 자세한 내용은 PEP 492 [https://peps.python.org/pep-0492/]를 참조하십시오.

Added in version 3.5.

inspect.CO_ASYNC_GENERATOR

코드 객체가 비동기 제너레이터 함수일 때 이 플래그가 설정됩니다. 코드 객체가 실행될 때 비동기 제너레이터 객체가 반환됩니다. 자세한 내용은 PEP 525 [https://peps.python.org/pep-0525/]를 참조하십시오.

Added in version 3.6.

inspect.CO_HAS_DOCSTRING

The flag is set when there is a docstring for the code object in the source code. If set, it will be the first item in co_consts.

Added in version 3.14.

참고

이 플래그들은 CPython에만 해당하며, 다른 파이썬 구현에서는 정의되지 않을 수 있습니다. 또한 플래그는 구현 세부 사항이며, 향후 파이썬 배포에서 제거되거나 폐지될 수 있습니다. 모든 내부 검사에는 inspect 모듈의 공개 API를 사용하는 것이 좋습니다.

Buffer flags

class inspect.BufferFlags

This is an enum.IntFlag that represents the flags that can be passed to the __buffer__() method of objects implementing the buffer protocol.

The meaning of the flags is explained at 버퍼 요청 유형.

SIMPLE

WRITABLE

FORMAT

ND

STRIDES

C_CONTIGUOUS

F_CONTIGUOUS

ANY_CONTIGUOUS

INDIRECT

CONTIG

CONTIG_RO

STRIDED

STRIDED_RO

RECORDS

RECORDS_RO

FULL

FULL_RO

READ

WRITE

Added in version 3.12.

명령 줄 인터페이스

inspect 모듈은 명령 줄에서 기본 내부 검사 기능을 제공하기도 합니다.

기본적으로, 모듈의 이름을 받아들이고 해당 모듈의 소스를 인쇄합니다. 콜론과 대상 객체의 정규화된 이름을 덧붙여, 대신 모듈 내의 클래스나 함수를 인쇄 할 수 있습니다.

--details

소스 코드 대신에 지정된 객체에 대한 정보를 인쇄합니다

annotationlib — Functionality for introspecting annotations

Source code: Lib/annotationlib.py [https://github.com/python/cpython/tree/main/Lib/annotationlib.py]

The annotationlib module provides tools for introspecting annotations on modules, classes, and functions.

Annotations are lazily evaluated and often contain forward references to objects that are not yet defined when the annotation is created. This module provides a set of low-level tools that can be used to retrieve annotations in a reliable way, even in the presence of forward references and other edge cases.

This module supports retrieving annotations in three main formats (see Format), each of which works best for different use cases:

VALUE evaluates the annotations and returns their value. This is most straightforward to work with, but it may raise errors, for example if the annotations contain references to undefined names.

FORWARDREF returns ForwardRef objects for annotations that cannot be resolved, allowing you to inspect the annotations without evaluating them. This is useful when you need to work with annotations that may contain unresolved forward references.

STRING returns the annotations as a string, similar to how it would appear in the source file. This is useful for documentation generators that want to display annotations in a readable way.

The get_annotations() function is the main entry point for retrieving annotations. Given a function, class, or module, it returns an annotations dictionary in the requested format. This module also provides functionality for working directly with the annotate function that is used to evaluate annotations, such as get_annotate_function() and call_annotate_function(), as well as the call_evaluate_function() function for working with evaluate functions.

더 보기

PEP 649 [https://peps.python.org/pep-0649/] proposed the current model for how annotations work in Python.

PEP 749 [https://peps.python.org/pep-0749/] expanded on various aspects of PEP 649 [https://peps.python.org/pep-0649/] and introduced the annotationlib module.

Annotations Best Practices provides best practices for working with annotations.

typing-extensions [https://pypi.org/project/typing-extensions/] provides a backport of get_annotations() that works on earlier versions of Python.

Annotation semantics

The way annotations are evaluated has changed over the history of Python 3, and currently still depends on a future import. There have been execution models for annotations:

Stock semantics (default in Python 3.0 through 3.13; see PEP 3107 [https://peps.python.org/pep-3107/] and PEP 526 [https://peps.python.org/pep-0526/]): Annotations are evaluated eagerly, as they are encountered in the source code.

Stringified annotations (used with from __future__ import annotations in Python 3.7 and newer; see PEP 563 [https://peps.python.org/pep-0563/]): Annotations are stored as strings only.

Deferred evaluation (default in Python 3.14 and newer; see PEP 649 [https://peps.python.org/pep-0649/] and PEP 749 [https://peps.python.org/pep-0749/]): Annotations are evaluated lazily, only when they are accessed.

As an example, consider the following program:

def func(a: Cls) -> None:
    print(a)

class Cls: pass

print(func.__annotations__)

This will behave as follows:

Under stock semantics (Python 3.13 and earlier), it will throw a NameError at the line where func is defined, because Cls is an undefined name at that point.

Under stringified annotations (if from __future__ import annotations is used), it will print {'a': 'Cls', 'return': 'None'}.

Under deferred evaluation (Python 3.14 and later), it will print {'a': <class 'Cls'>, 'return': None}.

Stock semantics were used when function annotations were first introduced in Python 3.0 (by PEP 3107 [https://peps.python.org/pep-3107/]) because this was the simplest, most obvious way to implement annotations. The same execution model was used when variable annotations were introduced in Python 3.6 (by PEP 526 [https://peps.python.org/pep-0526/]). However, stock semantics caused problems when using annotations as type hints, such as a need to refer to names that are not yet defined when the annotation is encountered. In addition, there were performance problems with executing annotations at module import time. Therefore, in Python 3.7, PEP 563 [https://peps.python.org/pep-0563/] introduced the ability to store annotations as strings using the from __future__ import annotations syntax. The plan at the time was to eventually make this behavior the default, but a problem appeared: stringified annotations are more difficult to process for those who introspect annotations at runtime. An alternative proposal, PEP 649 [https://peps.python.org/pep-0649/], introduced the third execution model, deferred evaluation, and was implemented in Python 3.14. Stringified annotations are still used if from __future__ import annotations is present, but this behavior will eventually be removed.

Classes

class annotationlib.Format

An IntEnum describing the formats in which annotations can be returned. Members of the enum, or their equivalent integer values, can be passed to get_annotations() and other functions in this module, as well as to __annotate__ functions.

VALUE = 1

Values are the result of evaluating the annotation expressions.

FORWARDREF = 2

Values are real annotation values (as per Format.VALUE format) for defined values, and ForwardRef proxies for undefined values. Real objects may contain references to, ForwardRef proxy objects.

STRING = 3

Values are the text string of the annotation as it appears in the source code, up to modifications including, but not restricted to, whitespace normalizations and constant values optimizations.

The exact values of these strings may change in future versions of Python.

VALUE_WITH_FAKE_GLOBALS = 4

Special value used to signal that an annotate function is being evaluated in a special environment with fake globals. When passed this value, annotate functions should either return the same value as for the Format.VALUE format, or raise NotImplementedError to signal that they do not support execution in this environment. This format is only used internally and should not be passed to the functions in this module.

Added in version 3.14.

class annotationlib.ForwardRef

A proxy object for forward references in annotations.

Instances of this class are returned when the FORWARDREF format is used and annotations contain a name that cannot be resolved. This can happen when a forward reference is used in an annotation, such as when a class is referenced before it is defined.

__forward_arg__

A string containing the code that was evaluated to produce the ForwardRef. The string may not be exactly equivalent to the original source.

evaluate(*, globals=None, locals=None, type_params=None, owner=None)

Evaluate the forward reference, returning its value.

This may throw an exception, such as NameError, if the forward reference refers to names that do not exist. The arguments to this method can be used to provide bindings for names that would otherwise be undefined.

ForwardRef instances returned by get_annotations() retain references to information about the scope they originated from, so calling this method with no further arguments may be sufficient to evaluate such objects. ForwardRef instances created by other means may not have any information about their scope, so passing arguments to this method may be necessary to evaluate them successfully.

globals and locals are passed to eval(), representing the global and local namespaces in which the name is evaluated. type_params, if given, must be a tuple of type parameters that are in scope while the forward reference is being evaluated. owner is the object that owns the annotation from which the forward reference derives, usually a function, class, or module.

중요

Once a ForwardRef instance has been evaluated, it caches the evaluated value, and future calls to evaluate() will return the cached value, regardless of the parameters passed in.

Added in version 3.14.

Functions

annotationlib.annotations_to_string(annotations)

Convert an annotations dict containing runtime values to a dict containing only strings. If the values are not already strings, they are converted using value_to_string(). This is meant as a helper for user-provided annotate functions that support the STRING format but do not have access to the code creating the annotations.

For example, this is used to implement the STRING for typing.TypedDict classes created through the functional syntax:

>>> from typing import TypedDict
>>> Movie = TypedDict("movie", {"name": str, "year": int})
>>> get_annotations(Movie, format=Format.STRING)
{'name': 'str', 'year': 'int'}

Added in version 3.14.

annotationlib.call_annotate_function(annotate, format, *, owner=None)

Call the annotate function annotate with the given format, a member of the Format enum, and return the annotations dictionary produced by the function.

This helper function is required because annotate functions generated by the compiler for functions, classes, and modules only support the VALUE format when called directly. To support other formats, this function calls the annotate function in a special environment that allows it to produce annotations in the other formats. This is a useful building block when implementing functionality that needs to partially evaluate annotations while a class is being constructed.

owner is the object that owns the annotation function, usually a function, class, or module. If provided, it is used in the FORWARDREF format to produce a ForwardRef object that carries more information.

더 보기

PEP 649 [https://peps.python.org/pep-0649/#the-stringizer-and-the-fake-globals-environment] contains an explanation of the implementation technique used by this function.

Added in version 3.14.

annotationlib.call_evaluate_function(evaluate, format, *, owner=None)

Call the evaluate function evaluate with the given format, a member of the Format enum, and return the value produced by the function. This is similar to call_annotate_function(), but the latter always returns a dictionary mapping strings to annotations, while this function returns a single value.

This is intended for use with the evaluate functions generated for lazily evaluated elements related to type aliases and type parameters:

typing.TypeAliasType.evaluate_value(), the value of type aliases

typing.TypeVar.evaluate_bound(), the bound of type variables

typing.TypeVar.evaluate_constraints(), the constraints of type variables

typing.TypeVar.evaluate_default(), the default value of type variables

typing.ParamSpec.evaluate_default(), the default value of parameter specifications

typing.TypeVarTuple.evaluate_default(), the default value of type variable tuples

owner is the object that owns the evaluate function, such as the type alias or type variable object.

format can be used to control the format in which the value is returned:

>>> type Alias = undefined
>>> call_evaluate_function(Alias.evaluate_value, Format.VALUE)
Traceback (most recent call last):
...
NameError: name 'undefined' is not defined
>>> call_evaluate_function(Alias.evaluate_value, Format.FORWARDREF)
ForwardRef('undefined')
>>> call_evaluate_function(Alias.evaluate_value, Format.STRING)
'undefined'

Added in version 3.14.

annotationlib.get_annotate_function(obj)

Retrieve the annotate function for obj. Return None if obj does not have an annotate function.

This is usually equivalent to accessing the __annotate__ attribute of obj, but direct access to the attribute may return the wrong object in certain situations involving metaclasses. This function should be used instead of accessing the attribute directly.

Added in version 3.14.

annotationlib.get_annotations(obj, *, globals=None, locals=None, eval_str=False, format=Format.VALUE)

Compute the annotations dict for an object.

obj may be a callable, class, module, or other object with __annotate__ and __annotations__ attributes. Passing in an object of any other type raises TypeError.

The format parameter controls the format in which annotations are returned, and must be a member of the Format enum or its integer equivalent.

Returns a dict. get_annotations() returns a new dict every time it’s called; calling it twice on the same object will return two different but equivalent dicts.

This function handles several details for you:

If eval_str is true, values of type str will be un-stringized using eval(). This is intended for use with stringized annotations (from __future__ import annotations). It is an error to set eval_str to true with formats other than Format.VALUE.

If obj doesn’t have an annotations dict, returns an empty dict. (Functions and methods always have an annotations dict; classes, modules, and other types of callables may not.)

Ignores inherited annotations on classes, as well as annotations on metaclasses. If a class doesn’t have its own annotations dict, returns an empty dict.

All accesses to object members and dict values are done using getattr() and dict.get() for safety.

eval_str controls whether or not values of type str are replaced with the result of calling eval() on those values:

If eval_str is true, eval() is called on values of type str. (Note that get_annotations() doesn’t catch exceptions; if eval() raises an exception, it will unwind the stack past the get_annotations() call.)

If eval_str is false (the default), values of type str are unchanged.

globals and locals are passed in to eval(); see the documentation for eval() for more information. If globals or locals is None, this function may replace that value with a context-specific default, contingent on type(obj):

If obj is a module, globals defaults to obj.__dict__.

If obj is a class, globals defaults to sys.modules[obj.__module__].__dict__ and locals defaults to the obj class namespace.

If obj is a callable, globals defaults to obj.__globals__, although if obj is a wrapped function (using functools.update_wrapper()) or a functools.partial object, it is unwrapped until a non-wrapped function is found.

Calling get_annotations() is best practice for accessing the annotations dict of any object. See Annotations Best Practices for more information on annotations best practices.

>>> def f(a: int, b: str) -> float:
...     pass
>>> get_annotations(f)
{'a': <class 'int'>, 'b': <class 'str'>, 'return': <class 'float'>}

Added in version 3.14.

annotationlib.value_to_string(value)

Convert an arbitrary Python value to a format suitable for use by the STRING format. This calls repr() for most objects, but has special handling for some objects, such as type objects.

This is meant as a helper for user-provided annotate functions that support the STRING format but do not have access to the code creating the annotations. It can also be used to provide a user-friendly string representation for other objects that contain values that are commonly encountered in annotations.

Added in version 3.14.

site — Site-specific configuration hook

소스 코드: Lib/site.py [https://github.com/python/cpython/tree/main/Lib/site.py]

이 모듈은 초기화 중에 자동으로 임포트 됩니다. 인터프리터의 -S 옵션을 사용하여 자동 임포트를 억제할 수 있습니다.

Importing this module normally appends site-specific paths to the module search path and adds callables, including help() to the built-in namespace. However, Python startup option -S blocks this and this module can be safely imported with no automatic modifications to the module search path or additions to the builtins. To explicitly trigger the usual site-specific additions, call the main() function.

버전 3.3에서 변경: -S를 사용하는 경우에도 모듈을 임포트 하면 경로 조작을 트리거 했습니다.

It starts by constructing up to four directories from a head and a tail part. For the head part, it uses sys.prefix and sys.exec_prefix; empty heads are skipped. For the tail part, it uses the empty string and then lib/site-packages (on Windows) or lib/pythonX.Y[t]/site-packages (on Unix and macOS). (The optional suffix “t” indicates the free threading build, and is appended if "t" is present in the sys.abiflags constant.) For each of the distinct head-tail combinations, it sees if it refers to an existing directory, and if so, adds it to sys.path and also inspects the newly added path for configuration files.

버전 3.5에서 변경: “site-python” 디렉터리에 대한 지원이 제거되었습니다.

버전 3.13에서 변경: On Unix, Free threading Python installations are identified by the “t” suffix in the version-specific directory name, such as lib/python3.13t/.

버전 3.14에서 변경: site is no longer responsible for updating sys.prefix and sys.exec_prefix on Virtual Environments. This is now done during the path initialization. As a result, under Virtual Environments, sys.prefix and sys.exec_prefix no longer depend on the site initialization, and are therefore unaffected by -S.

When running under a virtual environment, the pyvenv.cfg file in sys.prefix is checked for site-specific configurations. If the include-system-site-packages key exists and is set to true (case-insensitive), the system-level prefixes will be searched for site-packages, otherwise they won’t.

경로 구성 파일은 이름이 name.pth 인 파일이며, 위에서 언급한 4개의 디렉터리 중 하나에 존재합니다; 내용은 sys.path에 추가될 추가 항목(한 줄에 하나씩)입니다. 존재하지 않는 항목은 sys.path에 추가되지 않으며, 항목이 파일이 아닌 디렉터리를 참조하는지 확인하지 않습니다. 어떤 항목도 sys.path에 두 번 추가되지 않습니다. 빈 줄과 #으로 시작하는 줄은 건너뜁니다. import로 시작하는 (공백이나 탭이 뒤따르는) 줄은 실행됩니다.

참고

.pth 파일의 실행 줄은 특정 모듈이 실제 사용될지에 관계없이 모든 파이썬 시작 시에 실행됩니다. 따라서 영향을 최소화해야 합니다. 실행 줄의 주요 목적은 해당 모듈을 임포트 가능하게 만드는 것입니다 (제삼자 임포트 훅 로드, PATH 조정 등). 다른 초기화는 모듈의 실제 임포트에서 수행된다고 간주합니다, (임포트 한다면 그리고 임포트 할 때). 코드 청크를 한 줄로 제한하는 것은 여기에 더 복잡한 것을 넣지 않도록 하려는 의도입니다.

버전 3.13에서 변경: The .pth files are now decoded by UTF-8 at first and then by the locale encoding if it fails.

예를 들어, sys.prefix와 sys.exec_prefix가 /usr/local로 설정되었다고 가정하십시오. 그러면 파이썬 X.Y 라이브러리는 /usr/local/lib/pythonX.Y에 설치되어 있습니다. 여기에 foo, bar 및 spam이라는 세 개의 서브 디렉터리와, foo.pth와 bar.pth라는 두 개의 경로 구성 파일이 있는 서브 디렉터리 /usr/local/lib/pythonX.Y/site-packages가 있다고 가정하십시오. foo.pth에 다음이 포함되어 있고:

# foo package configuration

foo
bar
bletch

bar.pth는 다음을 포함한다고 가정하십시오:

# bar package configuration

bar

그러면 다음과 같은 버전 별 디렉터리가 이 순서대로 sys.path에 추가됩니다:

/usr/local/lib/pythonX.Y/site-packages/bar
/usr/local/lib/pythonX.Y/site-packages/foo

bletch가 존재하지 않기 때문에 생략되었음에 유의하십시오; bar.pth가 알파벳순으로 foo.pth 앞에 오기 때문에 bar 디렉터리가 foo 디렉터리보다 앞에 옵니다; spam은 경로 구성 파일에 언급되어 있지 않기 때문에 생략되었습니다.

sitecustomize

After these path manipulations, an attempt is made to import a module named sitecustomize, which can perform arbitrary site-specific customizations. It is typically created by a system administrator in the site-packages directory. If this import fails with an ImportError or its subclass exception, and the exception’s name attribute equals to 'sitecustomize', it is silently ignored. If Python is started without output streams available, as with pythonw.exe on Windows (which is used by default to start IDLE), attempted output from sitecustomize is ignored. Any other exception causes a silent and perhaps mysterious failure of the process.

usercustomize

After this, an attempt is made to import a module named usercustomize, which can perform arbitrary user-specific customizations, if ENABLE_USER_SITE is true. This file is intended to be created in the user site-packages directory (see below), which is part of sys.path unless disabled by -s. If this import fails with an ImportError or its subclass exception, and the exception’s name attribute equals to 'usercustomize', it is silently ignored.

유닉스가 아닌 일부 시스템에서는, sys.prefix와 sys.exec_prefix가 비어 있고, 경로 조작을 건너뜀에 유의하십시오; 하지만 sitecustomize와 usercustomize 임포트는 여전히 시도됩니다.

Readline 구성

readline을 지원하는 시스템에서, 파이썬이 대화형 모드로 -S 옵션 없이 시작되면, 이 모듈은 rlcompleter 모듈을 임포트하고 구성합니다. 기본 동작은 탭 완성을 활성화하고 ~/.python_history를 히스토리 저장 파일로 사용하는 것입니다. 이를 비활성화하려면, sitecustomize나 usercustomize 모듈 또는 PYTHONSTARTUP 파일에서 sys.__interactivehook__ 어트리뷰트를 삭제(또는 재정의)하십시오.

버전 3.4에서 변경: rlcompleter와 히스토리 활성화가 자동으로 이루어졌습니다.

모듈 내용

site.PREFIXES

site-packages 디렉터리의 접두사 리스트.

site.ENABLE_USER_SITE

사용자 site-packages 디렉터리의 상태를 나타내는 플래그. True는 활성화되어 sys.path에 추가되었음을 의미합니다. False는 사용자 요청(-s나 PYTHONNOUSERSITE로)에 의해 비활성화되었음을 의미합니다. None은 보안상의 이유(사용자나 그룹 id와 유효(effective) id가 일치하지 않음)로 또는 관리자에 의해 비활성화되었음을 의미합니다.

site.USER_SITE

Path to the user site-packages for the running Python. Can be None if getusersitepackages() hasn’t been called yet. Default value is ~/.local/lib/pythonX.Y[t]/site-packages for UNIX and non-framework macOS builds, ~/Library/Python/X.Y/lib/python/site-packages for macOS framework builds, and %APPDATA%\Python\PythonXY\site-packages on Windows. The optional “t” indicates the free-threaded build. This directory is a site directory, which means that .pth files in it will be processed.

site.USER_BASE

Path to the base directory for the user site-packages. Can be None if getuserbase() hasn’t been called yet. Default value is ~/.local for UNIX and macOS non-framework builds, ~/Library/Python/X.Y for macOS framework builds, and %APPDATA%\Python for Windows. This value is used to compute the installation directories for scripts, data files, Python modules, etc. for the user installation scheme. See also PYTHONUSERBASE.

site.main()

모든 표준 사이트별 디렉터리를 모듈 검색 경로에 추가합니다. 파이썬 인터프리터가 -S 플래그로 시작되지 않았으면, 이 모듈이 임포트 될 때 이 함수가 자동으로 호출됩니다.

버전 3.3에서 변경: 이 함수는 무조건 호출되었습니다.

site.addsitedir(sitedir, known_paths=None)

sys.path에 디렉터리를 추가하고 .pth 파일을 처리합니다. 일반적으로 sitecustomize나 usercustomize에서 사용됩니다 (위를 참조하십시오).

site.getsitepackages()

모든 전역 site-packages 디렉터리를 포함하는 리스트를 반환합니다.

Added in version 3.2.

site.getuserbase()

사용자 베이스 디렉터리 USER_BASE의 경로를 반환합니다. 아직 초기화되지 않았으면, 이 함수는 PYTHONUSERBASE를 따라 설정합니다.

Added in version 3.2.

site.getusersitepackages()

사용자별 site-packages 디렉터리 USER_SITE의 경로를 반환합니다. 아직 초기화되지 않았으면, 이 함수는 USER_BASE를 따라 설정합니다. 사용자별 site-packages가 sys.path에 추가되었는지 확인하려면 ENABLE_USER_SITE를 사용해야 합니다.

Added in version 3.2.

명령 줄 인터페이스

site 모듈은 명령 줄에서 사용자 디렉터리를 얻는 방법도 제공합니다:

$ python -m site --user-site
/home/user/.local/lib/python3.11/site-packages

인자 없이 호출되면, 표준 출력에 sys.path의 내용을 인쇄한 다음, USER_BASE의 값과 디렉터리가 존재하는지를 인쇄하고, USER_SITE에 대해 같은 것을 인쇄하고, 마지막으로 ENABLE_USER_SITE의 값을 인쇄합니다.

--user-base

사용자 베이스 디렉터리의 경로를 인쇄합니다.

--user-site

사용자 site-packages 디렉터리의 경로를 인쇄합니다.

두 옵션이 모두 제공되면, os.pathsep으로 구분하여, 사용자 베이스와 사용자 사이트를 (항상 이 순서대로) 인쇄합니다.

어떤 옵션이건 제공되면, 스크립트는 다음 값 중 하나로 종료됩니다: 사용자 site-packages 디렉터리가 활성화되었으면 0, 사용자에 의해 비활성화되었으면 1, 보안상의 이유나 관리자에 의해 비활성화되었으면 2, 그리고 에러가 있으면 2보다 큰 값.

더 보기

PEP 370 [https://peps.python.org/pep-0370/] – 사용자별 site-packages 디렉터리

The initialization of the sys.path module search path – The initialization of sys.path.

사용자 정의 파이썬 인터프리터

The modules described in this chapter allow writing interfaces similar to Python’s interactive interpreter. If you want a Python interpreter that supports some special feature in addition to the Python language, you should look at the code module. (The codeop module is lower-level, used to support compiling a possibly incomplete chunk of Python code.)

이 장에서 설명하는 모듈의 전체 목록은 다음과 같습니다:

code — Interpreter base classes

InteractiveInterpreter

InteractiveConsole

interact()

compile_command()

대화형 인터프리터 객체

runsource()

runcode()

showsyntaxerror()

showtraceback()

write()

대화형 콘솔 객체

interact()

push()

resetbuffer()

raw_input()

codeop — Compile Python code

compile_command()

Compile

CommandCompiler

code — Interpreter base classes

소스 코드: Lib/code.py [https://github.com/python/cpython/tree/main/Lib/code.py]

code 모듈은 파이썬에서 REPL(read-eval-print loop)을 구현하는 기능을 제공합니다. 대화형 인터프리터 프롬프트를 제공하는 응용 프로그램을 만드는 데 사용할 수 있는 두 개의 클래스와 편리 함수들이 포함되어 있습니다.

class code.InteractiveInterpreter(locals=None)

This class deals with parsing and interpreter state (the user’s namespace); it does not deal with input buffering or prompting or input file naming (the filename is always passed in explicitly). The optional locals argument specifies a mapping to use as the namespace in which code will be executed; it defaults to a newly created dictionary with key '__name__' set to '__console__' and key '__doc__' set to None.

class code.InteractiveConsole(locals=None, filename='<console>', local_exit=False)

Closely emulate the behavior of the interactive Python interpreter. This class builds on InteractiveInterpreter and adds prompting using the familiar sys.ps1 and sys.ps2, and input buffering. If local_exit is true, exit() and quit() in the console will not raise SystemExit, but instead return to the calling code.

버전 3.13에서 변경: Added local_exit parameter.

code.interact(banner=None, readfunc=None, local=None, exitmsg=None, local_exit=False)

Convenience function to run a read-eval-print loop. This creates a new instance of InteractiveConsole and sets readfunc to be used as the InteractiveConsole.raw_input() method, if provided. If local is provided, it is passed to the InteractiveConsole constructor for use as the default namespace for the interpreter loop. If local_exit is provided, it is passed to the InteractiveConsole constructor. The interact() method of the instance is then run with banner and exitmsg passed as the banner and exit message to use, if provided. The console object is discarded after use.

버전 3.6에서 변경: exitmsg 매개 변수가 추가되었습니다.

버전 3.13에서 변경: Added local_exit parameter.

code.compile_command(source, filename='<input>', symbol='single')

이 함수는 파이썬의 인터프리터 메인 루프(소위 REPL)를 흉내 내고 싶은 프로그램에 유용합니다. 까다로운 부분은 사용자가 후에 추가의 텍스트를 입력해서 완성할 수 있는 불완전한 명령을 입력했는지를 결정하는 것입니다 (완전한 명령이나 문법 에러가 아니라). 이 함수는 거의 항상 실제 인터프리터 메인 루프와 같은 결정을 내립니다.

source는 소스 문자열입니다; filename은 소스를 읽어 들인 선택적 파일명이며, 기본값은 '<input>'입니다; 그리고 symbol은 선택적 문법 시작 기호이며 'single' (기본값), 'eval' 또는 'exec' 중 하나여야 합니다.

명령이 완전하고 유효하면 코드 객체(compile(source, filename, symbol)와 같습니다)를 반환합니다; 명령이 불완전하면 None을 반환합니다; 명령이 완전하고 문법 에러가 있으면 SyntaxError를 발생시키고, 명령에 유효하지 않은 리터럴이 포함되었으면 OverflowError나 ValueError를 발생시킵니다.

대화형 인터프리터 객체

InteractiveInterpreter.runsource(source, filename='<input>', symbol='single')

인터프리터에서 소스를 컴파일하고 실행합니다. 인자는 compile_command()와 같습니다; filename의 기본값은 '<input>'이고, symbol의 기본값은 'single'입니다. 여러 가지 중 하나가 발생할 수 있습니다:

입력이 잘못되었습니다; compile_command()가 예외(SyntaxError나 OverflowError)를 발생시켰습니다. 문법 트레이스백이 showsyntaxerror() 메서드를 호출하여 인쇄됩니다. runsource()는 False를 반환합니다.

입력이 불완전하고, 더 많은 입력이 필요합니다; compile_command()가 None을 반환했습니다. runsource()는 True를 반환합니다.

입력이 완전합니다; compile_command()가 코드 객체를 반환했습니다. 코드는 runcode()(SystemExit를 제외한 실행 시간 예외도 처리합니다)를 호출하여 실행됩니다. runsource()는 False를 반환합니다.

반환 값은 다음 줄의 프롬프트에 sys.ps1과 sys.ps2 중 어느 것을 사용할지 결정하는 데 사용될 수 있습니다.

InteractiveInterpreter.runcode(code)

코드 객체를 실행합니다. 예외가 발생하면, showtraceback()가 호출되어 트레이스백을 표시합니다. 전파가 허락된 SystemExit를 제외한 모든 예외를 잡습니다.

KeyboardInterrupt에 대한 노트: 이 예외는 이 코드의 어딘가에서 발생할 수 있으며, 항상 잡히지는 않습니다. 호출자는 이것을 처리할 준비가 되어 있어야 합니다.

InteractiveInterpreter.showsyntaxerror(filename=None)

방금 발생한 문법 에러를 표시합니다. 스택 트레이스는 표시하지 않습니다, 문법 에러에는 그런 것이 없기 때문입니다. filename이 주어지면, 파이썬 구문 분석기가 제공하는 기본 파일명 대신에 예외에 채워집니다, 문자열에서 읽을 때는 항상 '<string>'을 사용하기 때문입니다. 출력은 write() 메서드로 기록됩니다.

InteractiveInterpreter.showtraceback()

방금 발생한 예외를 표시합니다. 첫 번째 스택 항목을 제거합니다, 그것은 인터프리터 객체 구현에 속하기 때문입니다. 출력은 write() 메서드로 기록됩니다.

버전 3.5에서 변경: 단지 기본(primary) 트레이스백이 아니라 전체 연결된(chained) 트레이스백이 표시됩니다.

InteractiveInterpreter.write(data)

문자열을 표준 에러 스트림(sys.stderr)에 기록합니다. 파생 클래스는 필요에 따라 적절한 출력 처리를 제공하기 위해 이것을 재정의해야 합니다.

대화형 콘솔 객체

InteractiveConsole 클래스는 InteractiveInterpreter의 서브 클래스이므로, 인터프리터 객체의 모든 메서드와 다음과 같은 추가 메서드를 제공합니다.

InteractiveConsole.interact(banner=None, exitmsg=None)

대화형 파이썬 콘솔을 가깝게 흉내 냅니다. 선택적 banner 인자는 첫 번째 상호 작용 전에 인쇄할 배너를 지정합니다; 기본적으로 표준 파이썬 인터프리터가 출력하는 것과 비슷한 배너를 출력한 다음 괄호 안에 콘솔 객체의 클래스 이름을 출력합니다 (실제 인터프리터와 혼동하지 않도록 하기 위함입니다 – 너무 비슷합니다!).

선택적 exitmsg 인자는 종료할 때 인쇄되는 종료 메시지를 지정합니다. 종료 메시지를 표시하지 않으려면 빈 문자열을 전달하십시오. exitmsg가 주어지지 않았거나 None이면, 기본 메시지가 인쇄됩니다.

버전 3.4에서 변경: 배너 인쇄를 억제하려면, 빈 문자열을 전달하십시오.

버전 3.6에서 변경: 종료할 때 종료 메시지를 인쇄합니다.

InteractiveConsole.push(line)

Push a line of source text to the interpreter. The line should not have a trailing newline; it may have internal newlines. The line is appended to a buffer and the interpreter’s runsource() method is called with the concatenated contents of the buffer as source. If this indicates that the command was executed or invalid, the buffer is reset; otherwise, the command is incomplete, and the buffer is left as it was after the line was appended. The return value is True if more input is required, False if the line was dealt with in some way (this is the same as runsource()).

InteractiveConsole.resetbuffer()

처리되지 않은 소스 텍스트를 입력 버퍼에서 제거합니다.

InteractiveConsole.raw_input(prompt='')

프롬프트를 기록하고 줄을 읽습니다. 반환된 줄에는 후행 줄 바꿈이 포함되지 않습니다. 사용자가 EOF 키 시퀀스를 입력하면, EOFError가 발생합니다. 기본 구현은 sys.stdin에서 읽습니다; 서브 클래스는 이것을 다른 구현으로 바꿀 수 있습니다.

codeop — Compile Python code

소스 코드: Lib/codeop.py [https://github.com/python/cpython/tree/main/Lib/codeop.py]

codeop 모듈은 code 모듈에서와같이 파이썬 읽기-평가-인쇄 루프를 에뮬레이트 할 수 있는 유틸리티를 제공합니다. 결과적으로, 모듈을 직접 사용하고 싶지 않을 것입니다; 여러분의 프로그램에 이러한 루프를 포함 시키려면 대신 code 모듈을 사용하는 것이 좋습니다.

이 작업에는 두 가지 부분이 있습니다:

Being able to tell if a line of input completes a Python statement: in short, telling whether to print ‘>>>’ or ‘...’ next.

Remembering which future statements the user has entered, so subsequent input can be compiled with these in effect.

codeop 모듈은 이들을 각각 수행하는 방법과 이들을 모두 수행하는 방법을 제공합니다.

단지 전자를 수행하려면:

codeop.compile_command(source, filename='<input>', symbol='single')

Tries to compile source, which should be a string of Python code and return a code object if source is valid Python code. In that case, the filename attribute of the code object will be filename, which defaults to '<input>'. Returns None if source is not valid Python code, but is a prefix of valid Python code.

source에 문제가 있으면, 예외가 발생합니다. 유효하지 않은 파이썬 구문이 있으면 SyntaxError가 발생하고, 유효하지 않은 리터럴이 있으면 OverflowError 나 ValueError가 발생합니다.

The symbol argument determines whether source is compiled as a statement ('single', the default), as a sequence of statement ('exec') or as an expression ('eval'). Any other value will cause ValueError to be raised.

참고

구문 분석기가 source의 끝에 도달하기 전에 성공적인 결과로 구문 분석을 중지하는 것이 가능합니다 (하지만 대체로 그렇지 않습니다); 이 경우, 뒤따르는 기호는 에러를 유발하는 대신 무시 될 수 있습니다. 예를 들어, 백 슬래시 뒤에 두 개의 개행이 오면 그 뒤에 임의의 가비지가 올 수 있습니다. 구문 분석기를 위한 API가 개선되면 이 문제가 해결될 것입니다.

class codeop.Compile

Instances of this class have __call__() methods identical in signature to the built-in function compile(), but with the difference that if the instance compiles program text containing a __future__ statement, the instance ‘remembers’ and compiles all subsequent program texts with the statement in force.

class codeop.CommandCompiler

Instances of this class have __call__() methods identical in signature to compile_command(); the difference is that if the instance compiles program text containing a __future__ statement, the instance ‘remembers’ and compiles all subsequent program texts with the statement in force.

모듈 임포트 하기

이 장에서 설명하는 모듈은 다른 파이썬 모듈을 임포트하는 새로운 방법과 임포트 절차를 사용자 정의하기 위한 훅을 제공합니다.

이 장에서 설명하는 모듈의 전체 목록은 다음과 같습니다:

zipimport — Import modules from Zip archives

ZipImportError

zipimporter 객체

zipimporter

create_module()

exec_module()

find_spec()

get_code()

get_data()

get_filename()

get_source()

is_package()

load_module()

invalidate_caches()

archive

prefix

예제

pkgutil — Package extension utility

ModuleInfo

extend_path()

get_importer()

iter_importers()

iter_modules()

walk_packages()

get_data()

resolve_name()

modulefinder — Find modules used by a script

AddPackagePath()

ReplacePackage()

ModuleFinder

report()

run_script()

modules

ModuleFinder의 사용 예

runpy — Locating and executing Python modules

run_module()

run_path()

importlib — import의 구현

소개

함수

__import__()

import_module()

invalidate_caches()

reload()

importlib.abc – import와 관련된 추상 베이스 클래스

MetaPathFinder

find_spec()

invalidate_caches()

PathEntryFinder

find_spec()

invalidate_caches()

Loader

create_module()

exec_module()

load_module()

ResourceLoader

get_data()

InspectLoader

get_code()

get_source()

is_package()

source_to_code()

exec_module()

load_module()

ExecutionLoader

get_filename()

FileLoader

name

path

load_module()

get_filename()

get_data()

SourceLoader

path_stats()

path_mtime()

set_data()

get_code()

exec_module()

load_module()

get_source()

is_package()

ResourceReader

open_resource()

resource_path()

is_resource()

contents()

Traversable

name

iterdir()

is_dir()

is_file()

joinpath()

__truediv__()

open()

read_bytes()

read_text()

TraversableResources

files()

importlib.machinery – 임포터와 경로 훅

SOURCE_SUFFIXES

DEBUG_BYTECODE_SUFFIXES

OPTIMIZED_BYTECODE_SUFFIXES

BYTECODE_SUFFIXES

EXTENSION_SUFFIXES

all_suffixes()

BuiltinImporter

FrozenImporter

WindowsRegistryFinder

PathFinder

find_spec()

invalidate_caches()

FileFinder

path

find_spec()

invalidate_caches()

path_hook()

SourceFileLoader

name

path

is_package()

path_stats()

set_data()

load_module()

SourcelessFileLoader

name

path

is_package()

get_code()

get_source()

load_module()

ExtensionFileLoader

name

path

create_module()

exec_module()

is_package()

get_code()

get_source()

get_filename()

NamespaceLoader

ModuleSpec

name

loader

origin

submodule_search_locations

loader_state

cached

parent

has_location

AppleFrameworkLoader

name

path

importlib.util – 임포터를 위한 유틸리티 코드

MAGIC_NUMBER

cache_from_source()

source_from_cache()

decode_source()

resolve_name()

find_spec()

module_from_spec()

spec_from_loader()

spec_from_file_location()

source_hash()

_incompatible_extension_module_restrictions()

LazyLoader

factory()

예

프로그래밍 방식으로 임포트 하기

모듈을 임포트 할 수 있는지 확인하기

소스 파일을 직접 임포트 하기

Implementing lazy imports

임포터 설정하기

importlib.import_module() 근사하기

importlib.resources – Package resource reading, opening and access

Anchor

files()

as_file()

Functional API

open_binary()

open_text()

read_binary()

read_text()

path()

is_resource()

contents()

importlib.resources.abc – Abstract base classes for resources

ResourceReader

open_resource()

resource_path()

is_resource()

contents()

Traversable

name

iterdir()

is_dir()

is_file()

joinpath()

__truediv__()

open()

read_bytes()

read_text()

TraversableResources

files()

importlib.metadata – Accessing package metadata

개요

PackageNotFoundError

기능적 API

진입 지점

entry_points()

EntryPoints

EntryPoint

배포 메타데이터

metadata()

PackageMetadata

배포 버전

version()

배포 파일

files()

PackagePath

배포 요구 사항

requires()

Mapping import to distribution packages

packages_distributions()

배포

distribution()

Distribution

Distribution Discovery

Implementing Custom Providers

Example

The initialization of the sys.path module search path

Virtual Environments

_pth files

Embedded Python

zipimport — Import modules from Zip archives

소스 코드: Lib/zipimport.py [https://github.com/python/cpython/tree/main/Lib/zipimport.py]

이 모듈은 파이썬 모듈(*.py, *.pyc)과 패키지를 ZIP-형식 저장소에서 임포트하는 기능을 추가합니다. 일반적으로 zipimport 모듈을 명시적으로 사용할 필요는 없습니다; ZIP 저장소 경로가 sys.path 항목에 있으면 내장 import 메커니즘에 의해 자동으로 사용됩니다.

일반적으로, sys.path는 문자열 디렉터리 이름의 리스트입니다. 이 모듈은 또한 sys.path 항목이 ZIP 파일 저장소를 명명하는 문자열이 될 수 있도록 합니다. ZIP 저장소에는 패키지 임포트를 지원하는 하위 디렉터리 구조가 포함될 수 있으며, 저장소 내의 경로를 지정하여 하위 디렉터리에서만 임포트 되도록 할 수 있습니다. 예를 들어, 경로 example.zip/lib/는 저장소 내의 lib/ 서브 디렉터리에서만 임포트하도록 합니다.

Any files may be present in the ZIP archive, but importers are only invoked for .py and .pyc files. ZIP import of dynamic modules (.pyd, .so) is disallowed. Note that if an archive only contains .py files, Python will not attempt to modify the archive by adding the corresponding .pyc file, meaning that if a ZIP archive doesn’t contain .pyc files, importing may be rather slow.

버전 3.13에서 변경: ZIP64 is supported

버전 3.8에서 변경: 전에는, 저장소 주석이 포함된 ZIP 저장소는 지원되지 않았습니다.

더 보기

PKZIP Application Note [https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT]

사용된 형식과 알고리즘 저자인 Phil Katz의 ZIP 파일 형식에 관한 설명서.

PEP 273 [https://peps.python.org/pep-0273/] - Zip 저장소에서 모듈 임포트

구현도 제공한 James C. Ahlstrom이 작성했습니다. 파이썬 2.3은 PEP 273 [https://peps.python.org/pep-0273/]의 명세를 따르지만, Just van Rossum이 작성한 구현을 사용하는데 PEP 302 [https://peps.python.org/pep-0302/]에 설명된 임포트 훅을 사용합니다.

importlib - The implementation of the import machinery

Package providing the relevant protocols for all importers to implement.

이 모듈은 예외를 정의합니다:

exception zipimport.ZipImportError

zipimporter 객체가 발생시키는 예외. ImportError의 서브 클래스이므로, ImportError로도 잡힐 수 있습니다.

zipimporter 객체

zipimporter는 ZIP 파일을 임포트하는 클래스입니다.

class zipimport.zipimporter(archivepath)

새로운 zipimporter 인스턴스를 만듭니다. archivepath는 ZIP 파일의 경로이거나, ZIP 파일 내의 특정 경로여야 합니다. 예를 들어, archivepath foo/bar.zip/lib는 ZIP 파일 foo/bar.zip 내의 lib 디렉터리에 있는 모듈을 찾습니다 (존재한다면).

archivepath가 유효한 ZIP 저장소를 가리키지 않으면 ZipImportError가 발생합니다.

버전 3.12에서 변경: Methods find_loader() and find_module(), deprecated in 3.10 are now removed. Use find_spec() instead.

create_module(spec)

Implementation of importlib.abc.Loader.create_module() that returns None to explicitly request the default semantics.

Added in version 3.10.

exec_module(module)

Implementation of importlib.abc.Loader.exec_module().

Added in version 3.10.

find_spec(fullname, target=None)

An implementation of importlib.abc.PathEntryFinder.find_spec().

Added in version 3.10.

get_code(fullname)

Return the code object for the specified module. Raise ZipImportError if the module couldn’t be imported.

get_data(pathname)

pathname와 관련된 데이터를 반환합니다. 파일을 찾을 수 없으면 OSError를 발생시킵니다.

버전 3.3에서 변경: IOError used to be raised, it is now an alias of OSError.

get_filename(fullname)

Return the value __file__ would be set to if the specified module was imported. Raise ZipImportError if the module couldn’t be imported.

Added in version 3.1.

get_source(fullname)

지정된 모듈의 소스 코드를 반환합니다. 모듈을 찾을 수 없으면 ZipImportError를 발생시키고, 저장소에 모듈이 있지만, 소스가 없으면 None을 반환합니다.

is_package(fullname)

fullname으로 지정된 모듈이 패키지면 True를 반환합니다. 모듈을 찾을 수 없으면 ZipImportError를 발생시킵니다.

load_module(fullname)

Load the module specified by fullname. fullname must be the fully qualified (dotted) module name. Returns the imported module on success, raises ZipImportError on failure.

버전 3.10부터 폐지됨: Use exec_module() instead.

invalidate_caches()

Clear out the internal cache of information about files found within the ZIP archive.

Added in version 3.10.

archive

있을 수도 있는 하위 경로를 제외한, 임포터와 연결된 ZIP 파일의 파일 이름.

prefix

모듈이 검색되는 ZIP 파일 내의 하위 경로. ZIP 파일의 루트를 가리키는 zipimporter 객체에서는 빈 문자열입니다.

archive와 prefix 어트리뷰트는, 슬래시로 결합 될 때, zipimporter 생성자에 지정된 원래 archivepath 인자와 같습니다.

예제

다음은 ZIP 저장소에서 모듈을 임포트하는 예제입니다 - zipimport 모듈이 명시적으로 사용되지 않음에 유의하십시오.

$ unzip -l example.zip
Archive:  example.zip
  Length     Date   Time    Name
 --------    ----   ----    ----
     8467  11-26-02 22:30   jwzthreading.py
 --------                   -------
     8467                   1 file
$ ./python
Python 2.3 (#1, Aug 1 2003, 19:54:32)
>>> import sys
>>> sys.path.insert(0, 'example.zip')  # Add .zip file to front of path
>>> import jwzthreading
>>> jwzthreading.__file__
'example.zip/jwzthreading.py'

pkgutil — Package extension utility

소스 코드: Lib/pkgutil.py [https://github.com/python/cpython/tree/main/Lib/pkgutil.py]

이 모듈은 임포트 시스템, 특히 패키지 지원을 위한 유틸리티를 제공합니다.

class pkgutil.ModuleInfo(module_finder, name, ispkg)

모듈 정보에 대한 간략한 요약을 담고 있는 네임드 튜플.

Added in version 3.6.

pkgutil.extend_path(path, name)

패키지를 구성하는 모듈의 검색 경로를 확장합니다. 의도된 사용법은 패키지의 __init__.py에 다음 코드를 삽입하는 것입니다:

from pkgutil import extend_path
__path__ = extend_path(__path__, __name__)

For each directory on sys.path that has a subdirectory that matches the package name, add the subdirectory to the package’s __path__. This is useful if one wants to distribute different parts of a single logical package as multiple directories.

It also looks for *.pkg files beginning where * matches the name argument. This feature is similar to *.pth files (see the site module for more information), except that it doesn’t special-case lines starting with import. A *.pkg file is trusted at face value: apart from skipping blank lines and ignoring comments, all entries found in a *.pkg file are added to the path, regardless of whether they exist on the filesystem (this is a feature).

입력 경로가 리스트가 아니면 (프로즌 패키지의 경우처럼) 변경되지 않은 상태로 반환됩니다. 입력 경로는 수정되지 않습니다; 확장한 사본이 반환됩니다. 항목은 사본의 끝에 추가되기만 합니다.

sys.path기 시퀀스라고 가정합니다. 존재하는 디렉터리를 참조하는 문자열이 아닌 sys.path 항목은 무시됩니다. 파일명으로 사용될 때 에러를 일으키는 sys.path의 유니코드 항목은 이 함수가 예외를 발생시키도록 할 수 있습니다 (os.path.isdir() 동작과 일치합니다).

pkgutil.get_importer(path_item)

주어진 path_item에 대한 파인더를 가져옵니다.

반환된 파인더는 경로 훅 때문에 새로 만들어지면 sys.path_importer_cache에 캐시 됩니다.

sys.path_hooks의 재검색이 필요하면, 캐시(또는 그 일부)를 수동으로 지울 수 있습니다.

버전 3.3에서 변경: 패키지 내부 PEP 302 [https://peps.python.org/pep-0302/] 임포트 에뮬레이션에 의존하는 대신, importlib에 직접 기반하도록 갱신되었습니다.

pkgutil.iter_importers(fullname='')

주어진 모듈 이름에 대해 파인더 객체를 산출(yield)합니다.

If fullname contains a '.', the finders will be for the package containing fullname, otherwise they will be all registered top level finders (i.e. those on both sys.meta_path and sys.path_hooks).

명명된 모듈이 패키지에 있으면, 이 함수를 호출하는 부작용으로 그 패키지를 임포트 합니다.

모듈 이름을 지정하지 않으면, 모든 최상위 수준 파인더가 생성됩니다.

버전 3.3에서 변경: 패키지 내부 PEP 302 [https://peps.python.org/pep-0302/] 임포트 에뮬레이션에 의존하는 대신, importlib에 직접 기반하도록 갱신되었습니다.

pkgutil.iter_modules(path=None, prefix='')

Yields ModuleInfo for all submodules on path, or, if path is None, all top-level modules on sys.path.

path는 None이거나 모듈을 찾을 경로의 리스트이어야 합니다.

prefix는 출력 시 모든 모듈 이름 앞에 출력할 문자열입니다.

참고

iter_modules() 메서드를 정의하는 파인더에서만 작동합니다. 이 인터페이스는 비표준이므로, 모듈은 importlib.machinery.FileFinder와 zipimport.zipimporter에 대한 구현도 제공합니다.

버전 3.3에서 변경: 패키지 내부 PEP 302 [https://peps.python.org/pep-0302/] 임포트 에뮬레이션에 의존하는 대신, importlib에 직접 기반하도록 갱신되었습니다.

pkgutil.walk_packages(path=None, prefix='', onerror=None)

path에 재귀적으로 포함된 모든 모듈이나, path가 None이면 모든 액세스할 수 있는 모듈에 대한 ModuleInfo를 산출(yield)합니다.

path는 None이거나 모듈을 찾을 경로의 리스트이어야 합니다.

prefix는 출력 시 모든 모듈 이름 앞에 출력할 문자열입니다.

서브 모듈 검색을 위한 __path__ 어트리뷰트에 액세스하기 위해, 이 함수는 주어진 path에 있는 모든 패키지(모든 모듈이 아닙니다!)를 임포트 해야 함에 유의하십시오.

onerror는 패키지 임포트를 시도하는 동안 예외가 발생하면 하나의 인자(임포트 하려는 패키지의 이름)로 호출되는 함수입니다. onerror 함수가 제공되지 않으면, ImportError는 잡아서 무시하고, 다른 모든 예외는 전파되어 검색이 종료됩니다.

예제:

# list all modules python can access
walk_packages()

# list all submodules of ctypes
walk_packages(ctypes.__path__, ctypes.__name__ + '.')

참고

iter_modules() 메서드를 정의하는 파인더에서만 작동합니다. 이 인터페이스는 비표준이므로, 모듈은 importlib.machinery.FileFinder와 zipimport.zipimporter에 대한 구현도 제공합니다.

버전 3.3에서 변경: 패키지 내부 PEP 302 [https://peps.python.org/pep-0302/] 임포트 에뮬레이션에 의존하는 대신, importlib에 직접 기반하도록 갱신되었습니다.

pkgutil.get_data(package, resource)

패키지에서 리소스를 가져옵니다.

이것은 로더 get_data API에 대한 래퍼입니다. package 인자는 표준 모듈 형식(foo.bar)의 패키지 이름이어야 합니다. resource 인자는 /를 경로 분리자로 사용하는 상대 파일명의 형식이어야 합니다. 상위 디렉터리 이름 ..는 허용되지 않으며, 루트에서 시작하는(/로 시작하는) 이름도 허용되지 않습니다.

이 함수는 지정된 리소스의 내용인 바이트열을 반환합니다.

파일시스템에 있는 패키지(이미 임포트 되었습니다)의 경우, 이것은 대략 다음과 동등합니다:

d = os.path.dirname(sys.modules[package].__file__)
data = open(os.path.join(d, resource), 'rb').read()

패키지를 찾거나 로드 할 수 없거나, 패키지가 get_data를 지원하지 않는 로더를 사용하면, None이 반환됩니다. 특히, 이름 공간 패키지를 위한 로더는 get_data를 지원하지 않습니다.

pkgutil.resolve_name(name)

이름을 객체로 해석합니다.

이 기능은 표준 라이브러리의 여러 곳에서 사용됩니다 (bpo-12915 [https://bugs.python.org/issue?@action=redirect&bpo=12915]를 참조하십시오) - 그리고 동등한 기능이 setuptools, Django 및 Pyramid와 같은 널리 사용되는 제삼자 패키지에도 있습니다.

name은 다음 형식 중 하나의 문자열 일 것으로 기대됩니다, 여기서 W는 유효한 파이썬 식별자를 나타내는 줄임 표현이며 점은 이러한 의사 정규식에서 리터럴 마침표를 나타냅니다:

W(.W)*

W(.W)*:(W(.W)*)?

첫 번째 형식은 이전 버전과의 호환성을 위해서만 사용됩니다. 점으로 구분된 이름의 일부는 패키지이고, 나머지는 패키지 내의 어딘가에 있는 객체이며, 다른 객체 안에 중첩되었을 수 있습니다. 패키지가 멈추고 객체 계층 구조가 시작되는 위치는 보는 것 만으로는 유추할 수 없습니다, 이 형식으로는 임포트 시도를 반복해서 수행해야합니다.

두 번째 형식에서, 호출자는 단일 콜론을 제공하여 구분 지점을 명확하게 만듭니다: 콜론 왼쪽의 점으로 구분된 이름은 임포트할 패키지이고, 오른쪽의 점으로 구분된 이름은 해당 패키지 내의 객체 계층 구조입니다. 이 형식에서는 한 번의 임포트만 필요합니다. 콜론으로 끝나면, 모듈 객체가 반환됩니다.

이 함수는 객체(모듈일 수 있습니다)를 반환하거나, 다음 예외 중 하나를 발생시킵니다:

ValueError – name이 인식되는 형식이 아니면.

ImportError – 그러지 말아야할 때 임포트가 실패하면.

AttributeError – 임포트한 패키지 내에서 객체 계층 구조를 탐색하여 원하는 객체에 도달하는 도중 실패가 발생할 때.

Added in version 3.9.

modulefinder — Find modules used by a script

소스 코드: Lib/modulefinder.py [https://github.com/python/cpython/tree/main/Lib/modulefinder.py]

이 모듈은 스크립트가 임포트 한 모듈 집합을 판단하는 데 사용할 수 있는 ModuleFinder 클래스를 제공합니다. modulefinder.py는 스크립트로 실행될 수도 있습니다, 인자로 파이썬 스크립트의 파일 이름을 지정하면, 임포트 된 모듈의 보고서가 인쇄됩니다.

modulefinder.AddPackagePath(pkg_name, path)

지정된 path에서 pkg_name 패키지를 찾을 수 있음을 기록합니다.

modulefinder.ReplacePackage(oldname, newname)

oldname 라는 이름의 모듈이 실제로는 newname라는 이름의 패키지라는 것을 지정할 수 있도록 합니다.

class modulefinder.ModuleFinder(path=None, debug=0, excludes=[], replace_paths=[])

이 클래스는 스크립트가 임포트하는 모듈 집합을 판단하는 run_script() 와 report() 메서드를 제공합니다. path는 모듈을 검색할 디렉터리 리스트일 수 있습니다; 지정되지 않으면, sys.path가 사용됩니다. debug는 디버깅 수준을 설정합니다; 값이 크면 클래스가 수행 중인 작업에 대한 디버깅 메시지를 인쇄합니다. excludes는 분석에서 제외할 모듈 이름 리스트입니다. replace_paths는 모듈 경로에서 교체될 (oldpath, newpath) 튜플의 리스트입니다.

report()

빠지거나 빠진 것으로 보이는 모듈뿐 아니라, 스크립트가 임포트하는 모듈과 그들의 경로의 목록에 관한 보고서를 표준 출력으로 인쇄합니다.

run_script(pathname)

파이썬 코드를 포함하는, pathname 파일의 내용을 분석합니다.

modules

모듈 이름을 모듈에 매핑하는 딕셔너리. ModuleFinder의 사용 예를 참조하십시오.

ModuleFinder의 사용 예

나중에 분석할 스크립트 (bacon.py):

import re, itertools

try:
    import baconhameggs
except ImportError:
    pass

try:
    import guido.python.ham
except ImportError:
    pass

bacon.py의 보고서를 출력하는 스크립트:

from modulefinder import ModuleFinder

finder = ModuleFinder()
finder.run_script('bacon.py')

print('Loaded modules:')
for name, mod in finder.modules.items():
    print('%s: ' % name, end='')
    print(','.join(list(mod.globalnames.keys())[:3]))

print('-'*50)
print('Modules not imported:')
print('\n'.join(finder.badmodules.keys()))

표본 출력(아키텍처에 따라 다를 수 있습니다):

Loaded modules:
_types:
copyreg:  _inverted_registry,_slotnames,__all__
re._compiler:  isstring,_sre,_optimize_unicode
_sre:
re._constants:  REPEAT_ONE,makedict,AT_END_LINE
sys:
re:  __module__,finditer,_expand
itertools:
__main__:  re,itertools,baconhameggs
re._parser:  _PATTERNENDERS,SRE_FLAG_UNICODE
array:
types:  __module__,IntType,TypeType
---------------------------------------------------
Modules not imported:
guido.python.ham
baconhameggs

runpy — Locating and executing Python modules

소스 코드: Lib/runpy.py [https://github.com/python/cpython/tree/main/Lib/runpy.py]

runpy 모듈은 파이썬 모듈을 먼저 임포트 하지 않고 찾아서 실행하는 데 사용합니다. 주요 용도는 파일 시스템이 아닌 파이썬 모듈 이름 공간을 사용하여 스크립트를 찾을 수 있는 -m 명령 줄 스위치를 구현하는 것입니다.

이것은 샌드박스 모듈이 아닙니다 - 모든 코드가 현재 프로세스에서 실행되고, 모든 부작용(가령 다른 모듈의 캐시된 임포트)은 함수가 반환된 후에도 그대로 유지됩니다.

또한, 실행된 코드에서 정의된 모든 함수와 클래스는 runpy 함수가 반환된 후 올바르게 작동하지 않을 수 있습니다. 이러한 제한이 주어진 사용 사례에 적합하지 않으면, 이 모듈보다 importlib가 더 적합한 선택일 수 있습니다.

runpy 모듈은 두 가지 함수를 제공합니다:

runpy.run_module(mod_name, init_globals=None, run_name=None, alter_sys=False)

Execute the code of the specified module and return the resulting module’s globals dictionary. The module’s code is first located using the standard import mechanism (refer to PEP 302 [https://peps.python.org/pep-0302/] for details) and then executed in a fresh module namespace.

The mod_name argument should be an absolute module name. If the module name refers to a package rather than a normal module, then that package is imported and the __main__ submodule within that package is then executed and the resulting module globals dictionary returned.

The optional dictionary argument init_globals may be used to pre-populate the module’s globals dictionary before the code is executed. init_globals will not be modified. If any of the special global variables below are defined in init_globals, those definitions are overridden by run_module().

The special global variables __name__, __spec__, __file__, __cached__, __loader__ and __package__ are set in the globals dictionary before the module code is executed. (Note that this is a minimal set of variables - other variables may be set implicitly as an interpreter implementation detail.)

__name__은 (이 선택적 인자가 None이 아니면) run_name으로, 명명된 모듈이 패키지면 mod_name + '.__main__'으로, 그렇지 않으면 mod_name 인자로 설정됩니다.

__spec__ will be set appropriately for the actually imported module (that is, __spec__.name will always be mod_name or mod_name + '.__main__', never run_name).

__file__, __cached__, __loader__ 및 __package__는 모듈 스펙에 따라 표준적으로 설정됩니다.

인자 alter_sys가 제공되고 True로 평가되면, sys.argv[0]은 __file__ 값으로 갱신되고 sys.modules[__name__]은 실행 중인 모듈에 대한 임시 모듈 객체로 갱신됩니다. sys.argv[0]과 sys.modules[__name__]은 함수가 반환되기 전에 원래 값으로 복원됩니다.

Note that this manipulation of sys is not thread-safe. Other threads may see the partially initialised module, as well as the altered list of arguments. It is recommended that the sys module be left alone when invoking this function from threaded code.

더 보기

명령 줄에서 동등한 기능을 제공하는 -m 옵션.

버전 3.1에서 변경: Added ability to execute packages by looking for a __main__ submodule.

버전 3.2에서 변경: __cached__ 전역 변수 추가 (PEP 3147 [https://peps.python.org/pep-3147/]을 참조하십시오).

버전 3.4에서 변경: PEP 451 [https://peps.python.org/pep-0451/]이 추가한 모듈 스펙 기능을 활용하도록 갱신되었습니다. 이것은 실제 모듈 이름을 항상 __spec__.name으로 액세스할 수 있으면서, __cached__가 이 방법으로 실행되는 모듈에 대해 올바르게 설정되도록 합니다.

버전 3.12에서 변경: The setting of __cached__, __loader__, and __package__ are deprecated. See ModuleSpec for alternatives.

runpy.run_path(path_name, init_globals=None, run_name=None)

Execute the code at the named filesystem location and return the resulting module’s globals dictionary. As with a script name supplied to the CPython command line, file_path may refer to a Python source file, a compiled bytecode file or a valid sys.path entry containing a __main__ module (e.g. a zipfile containing a top-level __main__.py file).

For a simple script, the specified code is simply executed in a fresh module namespace. For a valid sys.path entry (typically a zipfile or directory), the entry is first added to the beginning of sys.path. The function then looks for and executes a __main__ module using the updated path. Note that there is no special protection against invoking an existing __main__ entry located elsewhere on sys.path if there is no such module at the specified location.

The optional dictionary argument init_globals may be used to pre-populate the module’s globals dictionary before the code is executed. init_globals will not be modified. If any of the special global variables below are defined in init_globals, those definitions are overridden by run_path().

The special global variables __name__, __spec__, __file__, __cached__, __loader__ and __package__ are set in the globals dictionary before the module code is executed. (Note that this is a minimal set of variables - other variables may be set implicitly as an interpreter implementation detail.)

__name__은 (이 선택적 인자가 None이 아니면) run_name으로, 그렇지 않으면 '<run_path>'로 설정됩니다.

If file_path directly references a script file (whether as source or as precompiled byte code), then __file__ will be set to file_path, and __spec__, __cached__, __loader__ and __package__ will all be set to None.

If file_path is a reference to a valid sys.path entry, then __spec__ will be set appropriately for the imported __main__ module (that is, __spec__.name will always be __main__). __file__, __cached__, __loader__ and __package__ will be set as normal based on the module spec.

A number of alterations are also made to the sys module. Firstly, sys.path may be altered as described above. sys.argv[0] is updated with the value of file_path and sys.modules[__name__] is updated with a temporary module object for the module being executed. All modifications to items in sys are reverted before the function returns.

Note that, unlike run_module(), the alterations made to sys are not optional in this function as these adjustments are essential to allowing the execution of sys.path entries. As the thread-safety limitations still apply, use of this function in threaded code should be either serialised with the import lock or delegated to a separate process.

더 보기

명령 줄에서의 동등한 기능에 대한 인터페이스 옵션 (python path/to/script).

Added in version 3.2.

버전 3.4에서 변경: Updated to take advantage of the module spec feature added by PEP 451 [https://peps.python.org/pep-0451/]. This allows __cached__ to be set correctly in the case where __main__ is imported from a valid sys.path entry rather than being executed directly.

버전 3.12에서 변경: The setting of __cached__, __loader__, and __package__ are deprecated.

더 보기

PEP 338 [https://peps.python.org/pep-0338/] – 모듈을 스크립트로 실행하기

Nick Coghlan이 작성하고 구현한 PEP.

PEP 366 [https://peps.python.org/pep-0366/] – 메인 모듈 명시적 상대 임포트

Nick Coghlan이 작성하고 구현한 PEP.

PEP 451 [https://peps.python.org/pep-0451/] – 임포트 시스템의 ModuleSpec 형

Eric Snow가 작성하고 구현한 PEP

명령 줄과 환경 - CPython 명령 줄 세부 사항

importlib.import_module() 함수

importlib — import의 구현

Added in version 3.1.

소스 코드: Lib/importlib/__init__.py [https://github.com/python/cpython/tree/main/Lib/importlib/__init__.py]

소개

The purpose of the importlib package is three-fold.

One is to provide the implementation of the import statement (and thus, by extension, the __import__() function) in Python source code. This provides an implementation of import which is portable to any Python interpreter. This also provides an implementation which is easier to comprehend than one implemented in a programming language other than Python.

둘째, import를 구현하는 구성 요소가 이 패키지에서 노출되어, 사용자가 임포트 프로세스에 참여하기 위해 자신의 사용자 지정 객체(일반적으로 임포터라고 합니다)를 쉽게 만들 수 있도록 합니다.

Three, the package contains modules exposing additional functionality for managing aspects of Python packages:

importlib.metadata presents access to metadata from third-party distributions.

importlib.resources provides routines for accessing non-code “resources” from Python packages.

더 보기

임포트(import) 문

import 문의 언어 레퍼런스.

패키지 명세 [https://www.python.org/doc/essays/packages/]

패키지의 원래 명세. 이 문서를 작성한 이후로 일부 의미가 변경되었습니다 (예를 들어 sys.modules의 None을 기반으로 하는 리디렉션).

__import__() 함수

import 문은 이 함수의 편의 문법입니다.

The initialization of the sys.path module search path

The initialization of sys.path.

PEP 235 [https://peps.python.org/pep-0235/]

대소 문자를 구분하지 않는 플랫폼에서의 임포트

PEP 263 [https://peps.python.org/pep-0263/]

파이썬 소스 코드 인코딩 정의

PEP 302 [https://peps.python.org/pep-0302/]

새로운 임포트 훅

PEP 328 [https://peps.python.org/pep-0328/]

임포트: 다중 줄과 절대/상대

PEP 366 [https://peps.python.org/pep-0366/]

메인 모듈 명시적 상대 임포트

PEP 420 [https://peps.python.org/pep-0420/]

묵시적 이름 공간 패키지

PEP 451 [https://peps.python.org/pep-0451/]

임포트 시스템을 위한 ModuleSpec 형

PEP 488 [https://peps.python.org/pep-0488/]

PYO 파일 제거

PEP 489 [https://peps.python.org/pep-0489/]

다단계 확장 모듈 초기화

PEP 552 [https://peps.python.org/pep-0552/]

결정론적 pyc

PEP 3120 [https://peps.python.org/pep-3120/]

UTF-8을 기본 소스 인코딩으로 사용하기

PEP 3147 [https://peps.python.org/pep-3147/]

PYC 저장소 디렉터리

함수

importlib.__import__(name, globals=None, locals=None, fromlist=(), level=0)

내장 __import__() 함수의 구현.

참고

프로그래밍 방식으로 모듈을 임포트 하려면 이 함수 대신 import_module()을 사용해야 합니다.

importlib.import_module(name, package=None)

모듈을 임포트 합니다. name 인자는 절대나 상대적인 항으로 임포트 할 모듈을 지정합니다 (예를 들어 pkg.mod나 ..mod). 이름이 상대적인 항으로 지정되면, package 인자는 패키지 이름을 결정하기 위한 앵커 역할을 하는 패키지 이름으로 설정해야 합니다 (예를 들어 import_module('..mod', 'pkg.subpkg')는 pkg.mod를 임포트 합니다).

import_module() 함수는 importlib.__import__() 주위를 감싸는 단순화 래퍼 역할을 합니다. 이는 함수의 모든 의미가 importlib.__import__()에서 파생됨을 뜻합니다. 이 두 함수의 가장 중요한 차이점은 import_module()이 지정된 패키지나 모듈(예를 들어 pkg.mod)을 반환하는 반면, __import__()는 최상위 패키지나 모듈(예를 들어 pkg)을 반환한다는 것입니다.

인터프리터가 실행을 시작한 이후 만들어진 모듈(예를 들어, 파이썬 소스 파일을 만들면)을 동적으로 임포트 하는 경우, 임포트 시스템에서 새 모듈을 알 수 있도록 invalidate_caches()를 호출해야 할 수 있습니다.

버전 3.3에서 변경: 부모 패키지는 자동으로 임포트 됩니다.

importlib.invalidate_caches()

sys.meta_path에 저장된 파인더의 내부 캐시를 무효로 합니다. 파인더가 invalidate_caches()를 구현하면 무효화를 수행하기 위해 호출됩니다. 모든 파인더가 새로운 모듈의 존재를 알 수 있도록 프로그램이 실행되는 동안 모듈이 만들어진/설치된 경우 이 함수를 호출해야 합니다.

Added in version 3.3.

버전 3.10에서 변경: Namespace packages created/installed in a different sys.path location after the same namespace was already imported are noticed.

importlib.reload(module)

이전에 임포트 한 module을 다시 로드합니다. 인자는 모듈 객체여야 해서, 이전에 성공적으로 임포트 됐어야 합니다. 외부 편집기를 사용하여 모듈 소스 파일을 편집했고 파이썬 인터프리터를 떠나지 않고 새 버전을 시험해보고 싶을 때 유용합니다. 반환 값은 모듈 객체입니다 (재 임포트로 인해 다른 객체가 sys.modules에 배치되면 다를 수 있습니다).

reload()가 실행될 때:

파이썬 모듈의 코드가 다시 컴파일되고 모듈 수준 코드가 다시 실행되어, 원래 모듈을 로드한 로더를 재사용하여 모듈 딕셔너리에 있는 이름에 연결되는 새로운 객체 집합을 정의합니다. 확장 모듈의 init 함수는 두 번째에는 호출되지 않습니다.

파이썬의 다른 모든 객체와 마찬가지로 이전 객체는 참조 횟수가 0으로 떨어진 후에만 자원이 회수됩니다.

모듈 이름 공간의 이름은 새로운 객체나 변경된 객체를 가리키도록 갱신됩니다.

이전 객체에 대한 다른 참조(가령 모듈 외부의 이름)는 새 객체를 참조하기 위해 다시 연결되지 않으며 필요하다면 그들이 등장하는 각 이름 공간에서 갱신되어야 합니다.

다른 여러 가지 경고가 있습니다:

모듈을 다시 로드할 때, 그것의 (모듈의 전역 변수를 포함하는) 딕셔너리가 유지됩니다. 이름을 재정의하면 이전 정의를 대체해서, 일반적으로 문제가 되지 않습니다. 새 버전의 모듈이 이전 버전이 정의한 이름을 정의하지 않으면, 이전 정의가 그대로 남습니다. 이 기능은 객체의 전역 테이블이나 캐시를 유지한다면 모듈의 이점으로 사용될 수 있습니다 — try 문으로 테이블의 존재를 검사하고 필요하다면 초기화를 건너뛸 수 있습니다:

try:
    cache
except NameError:
    cache = {}

일반적으로 내장이나 동적으로 로드된 모듈을 다시 로드하는 것은 그리 유용하지 않습니다. sys, __main__, builtins 및 기타 주요 모듈을 다시 로드하지 않는 것이 좋습니다. 많은 경우 확장 모듈은 두 번 이상 초기화되도록 설계되지 않았으며, 다시 로드할 때 임의의 방식으로 실패할 수 있습니다.

모듈이 from … import …를 사용하여 다른 모듈에서 객체를 임포트 하면, 다른 모듈에 대해 reload()를 호출해도 그것에서 임포트 한 객체를 재정의하지 않습니다 — 이것을 피하는 한 가지 방법은 from 문을 다시 실행하는 것입니다, 다른 방법은 대신 import와 정규화된 이름(module.name)을 사용하는 것입니다.

모듈이 클래스의 인스턴스를 인스턴스 화하면, 클래스를 정의하는 모듈을 다시 로드해도 인스턴스의 메서드 정의에는 영향을 미치지 않습니다 — 이전 클래스 정의를 계속 사용합니다. 파생 클래스의 경우도 마찬가지입니다.

Added in version 3.4.

버전 3.7에서 변경: ModuleNotFoundError is raised when the module being reloaded lacks a ModuleSpec.

importlib.abc – import와 관련된 추상 베이스 클래스

소스 코드: Lib/importlib/abc.py [https://github.com/python/cpython/tree/main/Lib/importlib/abc.py]

importlib.abc 모듈에는 import에서 사용하는 모든 핵심 추상 베이스 클래스가 포함되어 있습니다. 핵심 ABC 구현에 도움이 되도록 핵심 추상 베이스 클래스의 일부 서브 클래스도 제공됩니다.

ABC 계층:

object
 +-- MetaPathFinder
 +-- PathEntryFinder
 +-- Loader
      +-- ResourceLoader --------+
      +-- InspectLoader          |
           +-- ExecutionLoader --+
                                 +-- FileLoader
                                 +-- SourceLoader

class importlib.abc.MetaPathFinder

An abstract base class representing a meta path finder.

Added in version 3.3.

버전 3.10에서 변경: No longer a subclass of Finder.

find_spec(fullname, path, target=None)

An abstract method for finding a spec for the specified module. If this is a top-level import, path will be None. Otherwise, this is a search for a subpackage or module and path will be the value of __path__ from the parent package. If a spec cannot be found, None is returned. When passed in, target is a module object that the finder may use to make a more educated guess about what spec to return. importlib.util.spec_from_loader() may be useful for implementing concrete MetaPathFinders.

Added in version 3.4.

invalidate_caches()

호출될 때, 파인더가 사용하는 내부 캐시를 무효로 해야 하는 선택적 메서드. sys.meta_path에서 모든 파인더의 캐시를 무효로 할 때 importlib.invalidate_caches()에서 사용합니다.

버전 3.4에서 변경: Returns None when called instead of NotImplemented.

class importlib.abc.PathEntryFinder

An abstract base class representing a path entry finder. Though it bears some similarities to MetaPathFinder, PathEntryFinder is meant for use only within the path-based import subsystem provided by importlib.machinery.PathFinder.

Added in version 3.3.

버전 3.10에서 변경: No longer a subclass of Finder.

find_spec(fullname, target=None)

지정된 모듈의 스펙을 찾는 추상 메서드. 파인더는 할당된 경로 엔트리 내에서만 모듈을 검색합니다. 스펙을 찾을 수 없으면, None이 반환됩니다. 전달될 때, target은 파인더가 반환할 스펙에 대해 더 정교하게 추측하기 위해 사용할 수 있는 모듈 객체입니다. importlib.util.spec_from_loader()는 구상 PathEntryFinders를 구현하는 데 유용할 수 있습니다.

Added in version 3.4.

invalidate_caches()

An optional method which, when called, should invalidate any internal cache used by the finder. Used by importlib.machinery.PathFinder.invalidate_caches() when invalidating the caches of all cached finders.

class importlib.abc.Loader

로더의 추상 베이스 클래스. 로더에 대한 정확한 정의는 PEP 302 [https://peps.python.org/pep-0302/]를 참조하십시오.

Loaders that wish to support resource reading should implement a get_resource_reader() method as specified by importlib.resources.abc.ResourceReader.

버전 3.7에서 변경: Introduced the optional get_resource_reader() method.

create_module(spec)

모듈을 임포트 할 때 사용할 모듈 객체를 반환하는 메서드. 이 메서드는 None을 반환해서 기본 모듈 생성 시맨틱이 적용되어야 함을 나타낼 수 있습니다.

Added in version 3.4.

버전 3.6에서 변경: This method is no longer optional when exec_module() is defined.

exec_module(module)

An abstract method that executes the module in its own namespace when a module is imported or reloaded. The module should already be initialized when exec_module() is called. When this method exists, create_module() must be defined.

Added in version 3.4.

버전 3.6에서 변경: create_module() must also be defined.

load_module(fullname)

A legacy method for loading a module. If the module cannot be loaded, ImportError is raised, otherwise the loaded module is returned.

If the requested module already exists in sys.modules, that module should be used and reloaded. Otherwise the loader should create a new module and insert it into sys.modules before any loading begins, to prevent recursion from the import. If the loader inserted a module and the load fails, it must be removed by the loader from sys.modules; modules already in sys.modules before the loader began execution should be left alone.

The loader should set several attributes on the module (note that some of these attributes can change when a module is reloaded):

module.__name__

module.__file__

module.__cached__ (deprecated)

module.__path__

module.__package__ (deprecated)

module.__loader__ (deprecated)

exec_module()을 사용할 수 있으면 이전 버전과 호환되는 기능이 제공됩니다.

버전 3.4에서 변경: Raise ImportError when called instead of NotImplementedError. Functionality provided when exec_module() is available.

버전 3.4부터 폐지됨: The recommended API for loading a module is exec_module() (and create_module()). Loaders should implement it instead of load_module(). The import machinery takes care of all the other responsibilities of load_module() when exec_module() is implemented.

class importlib.abc.ResourceLoader

스토리지 백 엔드에서 임의의 리소스를 로드하기 위한 선택적 PEP 302 [https://peps.python.org/pep-0302/] 프로토콜을 구현하는 로더의 추상 베이스 클래스.

버전 3.7부터 폐지됨: This ABC is deprecated in favour of supporting resource loading through importlib.resources.abc.ResourceReader.

abstractmethod get_data(path)

An abstract method to return the bytes for the data located at path. Loaders that have a file-like storage back-end that allows storing arbitrary data can implement this abstract method to give direct access to the data stored. OSError is to be raised if the path cannot be found. The path is expected to be constructed using a module’s __file__ attribute or an item from a package’s __path__.

버전 3.4에서 변경: NotImplementedError 대신 OSError를 발생시킵니다.

class importlib.abc.InspectLoader

모듈을 검사(inspect)하는 로더를 위한 선택적 PEP 302 [https://peps.python.org/pep-0302/] 프로토콜을 구현하는 로더의 추상 베이스 클래스.

get_code(fullname)

모듈에 대한 코드 객체나, 모듈에 코드 객체가 없으면 (예를 들어, 내장 모듈이 이런 경우입니다) None을 반환합니다. 로더가 요청한 모듈을 찾을 수 없으면 ImportError가 발생합니다.

참고

이 메서드에는 기본 구현이 있지만, 가능하다면 성능을 위해 재정의하는 것이 좋습니다.

버전 3.4에서 변경: 더는 추상적이지 않고 구상 구현이 제공됩니다.

abstractmethod get_source(fullname)

모듈의 소스를 반환하는 추상 메서드. 인식된 모든 줄 구분자를 '\n' 문자로 변환하는 유니버설 줄 넘김을 사용하여 텍스트 문자열로 반환됩니다. 사용 가능한 소스가 없으면 (예를 들어, 내장 모듈) None을 반환합니다. 로더가 지정된 모듈을 찾을 수 없으면 ImportError를 발생시킵니다.

버전 3.4에서 변경: NotImplementedError 대신 ImportError를 발생시킵니다.

is_package(fullname)

An optional method to return a true value if the module is a package, a false value otherwise. ImportError is raised if the loader cannot find the module.

버전 3.4에서 변경: NotImplementedError 대신 ImportError를 발생시킵니다.

static source_to_code(data, path='<string>')

파이썬 소스에서 코드 객체를 만듭니다.

data 인자는 compile() 함수가 지원하는 것은 무엇이든 될 수 있습니다 (즉 문자열이나 바이트열). path 인자는 소스 코드가 온 곳의 “경로”여야 하며, 추상 개념(예를 들어 zip 파일에서의 위치)일 수 있습니다.

후속 코드 객체를 사용하면 exec(code, module.__dict__)를 실행하여 그 코드를 모듈에서 실행할 수 있습니다.

Added in version 3.4.

버전 3.5에서 변경: 메서드를 정적(static)으로 만들었습니다.

exec_module(module)

Loader.exec_module()의 구현.

Added in version 3.4.

load_module(fullname)

Loader.load_module()의 구현.

버전 3.4부터 폐지됨: 대신 exec_module()을 사용하십시오.

class importlib.abc.ExecutionLoader

구현될 때, 모듈이 스크립트로 실행되도록 돕는 InspectLoader에서 상속되는 추상 베이스 클래스. ABC는 선택적 PEP 302 [https://peps.python.org/pep-0302/] 프로토콜을 표현합니다.

abstractmethod get_filename(fullname)

An abstract method that is to return the value of __file__ for the specified module. If no path is available, ImportError is raised.

소스 코드를 사용할 수 있으면, 메서드는 모듈을 로드하는 데 바이트 코드를 사용했는지와 관계없이 소스 파일의 경로를 반환해야 합니다.

버전 3.4에서 변경: NotImplementedError 대신 ImportError를 발생시킵니다.

class importlib.abc.FileLoader(fullname, path)

ResourceLoader와 ExecutionLoader를 상속하고 ResourceLoader.get_data()와 ExecutionLoader.get_filename()의 구상 구현을 제공하는 추상 베이스 클래스.

fullname 인자는 로더가 처리해야 하는 모듈의 완전히 결정된(resolved) 이름입니다. path 인자는 모듈의 파일 경로입니다.

Added in version 3.3.

name

로더가 처리할 수 있는 모듈의 이름.

path

모듈 파일의 경로.

load_module(fullname)

super의 load_module()을 호출합니다.

버전 3.4부터 폐지됨: 대신 Loader.exec_module()을 사용하십시오.

abstractmethod get_filename(fullname)

path를 반환합니다.

abstractmethod get_data(path)

path를 바이너리 파일로 읽고 그것의 바이트열을 반환합니다.

class importlib.abc.SourceLoader

소스 (및 선택적으로 바이트 코드) 파일 로드를 구현하기 위한 추상 베이스 클래스. 이 클래스는 ResourceLoader와 ExecutionLoader를 모두 상속하며, 다음을 구현해야 합니다:

ResourceLoader.get_data()

ExecutionLoader.get_filename()

소스 파일의 경로만 반환해야 합니다; 소스 없는 로딩은 지원되지 않습니다.

이 클래스에 의해 정의된 추상 메서드는 선택적 바이트 코드 파일 지원을 추가하는 것입니다. 이러한 선택적 메서드를 구현하지 않으면 (또는 그들이 NotImplementedError를 발생시키도록 하면) 로더가 소스 코드에 대해서만 작동하도록 만듭니다. 메서드를 구현하면 로더가 소스*와* 바이트 코드 파일 모두에 대해 작동하게 할 수 있습니다; 바이트 코드만 제공되는 소스 없는 로드는 허용하지 않습니다. 바이트 코드 파일은 파이썬 컴파일러의 구문 분석 단계를 제거하여 로딩 속도를 높이기 위한 최적화라서, 바이트 코드 전용 API는 노출되지 않습니다.

path_stats(path)

지정된 경로에 대한 메타 데이터를 포함하는 dict를 반환하는 선택적 추상 메서드. 지원되는 딕셔너리 키는 다음과 같습니다:

'mtime' (필수): 소스 코드의 수정 시간을 나타내는 정수나 부동 소수점 숫자;

'size' (선택): 바이트 단위의 소스 코드의 크기.

향후 확장을 위해, 딕셔너리의 다른 키는 무시됩니다. 경로를 처리할 수 없으면, OSError가 발생합니다.

Added in version 3.3.

버전 3.4에서 변경: NotImplementedError 대신 OSError를 발생시킵니다.

path_mtime(path)

지정된 경로의 수정 시간을 반환하는 선택적 추상 메서드.

버전 3.3부터 폐지됨: 이 메서드는 폐지되었고 path_stats()로 대체되었습니다. 구현할 필요는 없지만, 호환성을 위해 여전히 제공됩니다. 경로를 처리할 수 없으면 OSError를 발생시킵니다.

버전 3.4에서 변경: NotImplementedError 대신 OSError를 발생시킵니다.

set_data(path, data)

지정된 바이트열을 파일 경로에 쓰는 선택적 추상 메서드. 존재하지 않는 중간 디렉터리는 자동으로 만들어집니다.

When writing to the path fails because the path is read-only (errno.EACCES/PermissionError), do not propagate the exception.

버전 3.4에서 변경: 호출할 때 더는 NotImplementedError를 발생시키지 않습니다.

get_code(fullname)

InspectLoader.get_code()의 구상 구현.

exec_module(module)

Loader.exec_module()의 구상 구현.

Added in version 3.4.

load_module(fullname)

Loader.load_module()의 구상 구현.

버전 3.4부터 폐지됨: 대신 exec_module()을 사용하십시오.

get_source(fullname)

InspectLoader.get_source()의 구상 구현.

is_package(fullname)

InspectLoader.is_package()의 구상 구현. (ExecutionLoader.get_filename()에서 제공되는) 파일 경로가 파일 확장자를 제거했을 때 __init__라는 이름의 파일이고 동시에 모듈 이름 자체가 __init__로 끝나지 않으면 모듈은 패키지로 결정됩니다.

class importlib.abc.ResourceReader

Superseded by TraversableResources

리소스(resources)를 읽을 수 있는 기능을 제공하는 추상 베이스 클래스.

From the perspective of this ABC, a resource is a binary artifact that is shipped within a package. Typically this is something like a data file that lives next to the __init__.py file of the package. The purpose of this class is to help abstract out the accessing of such data files so that it does not matter if the package and its data file(s) are stored e.g. in a zip file versus on the file system.

이 클래스의 모든 메서드에서, resource 인자는 개념적으로 단지 파일 이름을 나타내는 경로류 객체가 될 것으로 기대됩니다. 이는 resource 인자에 서브 디렉터리 경로가 포함되지 않아야 함을 의미합니다. 판독기(reader)가 읽으려는 패키지의 위치가 “디렉터리”의 역할을 하기 때문입니다. 따라서 디렉터리와 파일 이름에 대한 은유는 각각 패키지와 리소스입니다. 이것은 또한 이 클래스의 인스턴스가 (잠재적으로 여러 패키지나 모듈을 나타내는 대신) 특정 패키지와 직접적으로 연관될 것으로 기대되는 이유입니다.

리소스 읽기를 지원하려는 로더는 이 ABC의 인터페이스를 구현하는 객체를 반환하는 get_resource_reader(fullname)이라는 메서드를 제공해야 합니다. fullname으로 지정된 모듈이 패키지가 아니면, 이 메서드는 None을 반환해야 합니다. 이 ABC와 호환되는 객체는 지정된 모듈이 패키지일 때만 반환해야 합니다.

Added in version 3.7.

Deprecated since version 3.12, removed in version 3.14: Use importlib.resources.abc.TraversableResources instead.

abstractmethod open_resource(resource)

resource의 바이너리 읽기를 위해 열린 파일류 객체를 반환합니다.

리소스를 찾을 수 없으면, FileNotFoundError 가 발생합니다.

abstractmethod resource_path(resource)

resource에 대한 파일 시스템 경로를 반환합니다.

리소스가 파일 시스템에 구체적으로 존재하지 않으면, FileNotFoundError 가 발생합니다.

abstractmethod is_resource(name)

명명된 name을 리소스로 간주하면 True를 반환합니다. name이 없으면, FileNotFoundError 가 발생합니다.

abstractmethod contents()

패키지 내용에 대한 문자열의 이터러블을 반환합니다. 이터레이터가 반환한 모든 이름이 실제 리소스일 필요는 없음에 유의하십시오, 예를 들어 is_resource()가 거짓인 이름을 반환하는 것이 허용됩니다.

리소스가 아닌 이름이 반환되도록 하는 것은 패키지와 그것의 리소스가 저장되는 방법이 사전에 알려졌고 리소스가 아닌 이름이 유용한 상황을 허용하기 위함입니다. 예를 들어, 패키지와 리소스가 파일 시스템에 저장되어있는 것으로 알려졌을 때 해당 서브 디렉터리 이름을 직접 사용할 수 있도록 서브 디렉터리 이름 반환이 허용됩니다.

추상 메서드는 항목이 없는 이터러블을 반환합니다.

class importlib.abc.Traversable

An object with a subset of pathlib.Path methods suitable for traversing directories and opening files.

For a representation of the object on the file-system, use importlib.resources.as_file().

Added in version 3.9.

Deprecated since version 3.12, removed in version 3.14: Use importlib.resources.abc.Traversable instead.

name

Abstract. The base name of this object without any parent references.

abstractmethod iterdir()

Yield Traversable objects in self.

abstractmethod is_dir()

Return True if self is a directory.

abstractmethod is_file()

Return True if self is a file.

abstractmethod joinpath(child)

Return Traversable child in self.

abstractmethod __truediv__(child)

Return Traversable child in self.

abstractmethod open(mode='r', *args, **kwargs)

mode may be ‘r’ or ‘rb’ to open as text or binary. Return a handle suitable for reading (same as pathlib.Path.open).

When opening as text, accepts encoding parameters such as those accepted by io.TextIOWrapper.

read_bytes()

Read contents of self as bytes.

read_text(encoding=None)

Read contents of self as text.

class importlib.abc.TraversableResources

An abstract base class for resource readers capable of serving the importlib.resources.files() interface. Subclasses importlib.resources.abc.ResourceReader and provides concrete implementations of the importlib.resources.abc.ResourceReader’s abstract methods. Therefore, any loader supplying importlib.abc.TraversableResources also supplies ResourceReader.

Loaders that wish to support resource reading are expected to implement this interface.

Added in version 3.9.

Deprecated since version 3.12, removed in version 3.14: Use importlib.resources.abc.TraversableResources instead.

abstractmethod files()

Returns a importlib.resources.abc.Traversable object for the loaded package.

importlib.machinery – 임포터와 경로 훅

소스 코드: Lib/importlib/machinery.py [https://github.com/python/cpython/tree/main/Lib/importlib/machinery.py]

이 모듈에는 import가 모듈을 찾고 로드하는 데 도움이 되는 다양한 객체가 포함되어 있습니다.

importlib.machinery.SOURCE_SUFFIXES

소스 모듈로 인식되는 파일 접미사를 나타내는 문자열 리스트.

Added in version 3.3.

importlib.machinery.DEBUG_BYTECODE_SUFFIXES

최적화되지 않은 바이트 코드 모듈의 파일 접미사를 나타내는 문자열 리스트.

Added in version 3.3.

버전 3.5부터 폐지됨: 대신 BYTECODE_SUFFIXES를 사용하십시오.

importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES

최적화된 바이트 코드 모듈의 파일 접미사를 나타내는 문자열 리스트.

Added in version 3.3.

버전 3.5부터 폐지됨: 대신 BYTECODE_SUFFIXES를 사용하십시오.

importlib.machinery.BYTECODE_SUFFIXES

바이트 코드 모듈로 인식되는 파일 접미사를 나타내는 문자열 리스트 (앞의 점을 포함합니다).

Added in version 3.3.

버전 3.5에서 변경: 이 값은 더는 __debug__에 의존하지 않습니다.

importlib.machinery.EXTENSION_SUFFIXES

확장 모듈로 인식되는 파일 접미사를 나타내는 문자열 리스트.

Added in version 3.3.

importlib.machinery.all_suffixes()

표준 임포트 절차가 인식하는 모듈의 모든 파일 접미사를 나타내는 문자열의 결합한 리스트를 반환합니다. 이것은 모듈 종류에 대한 세부 정보 없이 파일 시스템 경로가 잠재적으로 모듈을 참조하는지를 알아야 하는 코드(예를 들어, inspect.getmodulename())를 위한 도우미입니다.

Added in version 3.3.

class importlib.machinery.BuiltinImporter

내장 모듈용 임포터. 알려진 모든 내장 모듈은 sys.builtin_module_names에 나열되어 있습니다. 이 클래스는 importlib.abc.MetaPathFinder와 importlib.abc.InspectLoader ABC를 구현합니다.

이 클래스는 인스턴스 화의 필요성을 완화하기 위해 클래스 메서드만 정의합니다.

버전 3.5에서 변경: PEP 489 [https://peps.python.org/pep-0489/]의 일부로, 내장 임포터는 이제 Loader.create_module()과 Loader.exec_module()을 구현합니다.

class importlib.machinery.FrozenImporter

프로즌(frozen) 모듈용 임포터. 이 클래스는 importlib.abc.MetaPathFinder와 importlib.abc.InspectLoader ABC를 구현합니다.

이 클래스는 인스턴스 화의 필요성을 완화하기 위해 클래스 메서드만 정의합니다.

버전 3.4에서 변경: Loader.create_module()과 Loader.exec_module() 메서드를 얻었습니다.

class importlib.machinery.WindowsRegistryFinder

윈도우 레지스트리에 선언된 모듈용 파인더. 이 클래스는 importlib.abc.MetaPathFinder ABC를 구현합니다.

이 클래스는 인스턴스 화의 필요성을 완화하기 위해 클래스 메서드만 정의합니다.

Added in version 3.3.

버전 3.6부터 폐지됨: 대신 site 구성을 사용하십시오. 이후 버전의 파이썬은 기본적으로 이 파인더를 활성화하지 않을 수 있습니다.

class importlib.machinery.PathFinder

sys.path와 패키지 __path__ 어트리뷰트용 파인더. 이 클래스는 importlib.abc.MetaPathFinder ABC를 구현합니다.

이 클래스는 인스턴스 화의 필요성을 완화하기 위해 클래스 메서드만 정의합니다.

classmethod find_spec(fullname, path=None, target=None)

sys.path 또는, 정의되었다면, path에서 fullname에 의해 지정된 모듈에 대한 스펙을 찾으려고 시도하는 클래스 메서드. 검색된 각 경로 엔트리에 대해, sys.path_importer_cache가 확인됩니다. 거짓이 아닌 객체를 찾으면 검색 중인 모듈을 찾기 위한 경로 엔트리 파인더로 사용됩니다. sys.path_importer_cache에 엔트리가 없으면, sys.path_hooks에서 경로 엔트리를 위한 파인더를 검색하고, 발견되면, 모듈에 대해 조회되는 것과 동시에 sys.path_importer_cache에 저장됩니다. 파인더가 아예 발견되지 않으면 None이 캐시에 저장되고 반환됩니다.

Added in version 3.4.

버전 3.5에서 변경: 현재 작업 디렉터리 – 빈 문자열로 표현됩니다 – 가 더는 유효하지 않으면 None이 반환되지만 sys.path_importer_cache에 값이 캐시 되지는 않습니다.

classmethod invalidate_caches()

메서드를 정의하는 sys.path_importer_cache에 저장된 모든 파인더에 대해 importlib.abc.PathEntryFinder.invalidate_caches()를 호출합니다. sys.path_importer_cache에 None으로 설정된 엔트리가 삭제됩니다.

버전 3.7에서 변경: sys.path_importer_cache에서 None의 엔트리가 삭제됩니다.

버전 3.4에서 변경: ''(즉 빈 문자열)에 대해서는 현재 작업 디렉터리로 sys.path_hooks의 객체를 호출합니다.

class importlib.machinery.FileFinder(path, *loader_details)

파일 시스템에서의 결과를 캐시 하는 importlib.abc.PathEntryFinder 의 구상 구현.

path 인자는 파인더가 검색을 담당하는 디렉터리입니다.

loader_details 인자는 각각 로더와 로더가 인식하는 파일 접미사의 시퀀스를 포함하는 가변 개수의 2개 항목 튜플입니다. 로더는 모듈 이름과 찾은 파일의 경로로 구성되는 두 인자를 받아들이는 콜러블일 것으로 기대됩니다.

파인더는 필요에 따라 디렉터리 내용을 캐시 하여, 각 모듈 검색에서 stat 호출을 수행하여 캐시가 시효가 지나지 않았는지 확인합니다. 캐시 만료는 파일 시스템의 운영 체제 상태 정보의 세분성에 의존하기 때문에, 모듈 검색, 새 파일 생성 및 새 파일이 나타내는 모듈 검색의 잠재적 경쟁 조건이 있습니다. stat 호출의 세분성 이하로 연산이 아주 빠르게 수행되면, 모듈 검색이 실패합니다. 이를 방지하려면, 모듈을 동적으로 만들 때, importlib.invalidate_caches()를 호출해야 합니다.

Added in version 3.3.

path

파인더가 검색할 경로.

find_spec(fullname, target=None)

path 내에서 fullname을 처리할 스펙을 찾으려고 합니다.

Added in version 3.4.

invalidate_caches()

내부 캐시를 지웁니다.

classmethod path_hook(*loader_details)

A class method which returns a closure for use on sys.path_hooks. An instance of FileFinder is returned by the closure using the path argument given to the closure directly and loader_details indirectly.

클로저에 대한 인자가 기존 디렉터리가 아니면, ImportError가 발생합니다.

class importlib.machinery.SourceFileLoader(fullname, path)

importlib.abc.FileLoader를 서브 클래싱하고 다른 메서드의 구상 구현을 제공하는 importlib.abc.SourceLoader의 구상 구현.

Added in version 3.3.

name

이 로더가 처리할 모듈의 이름.

path

소스 파일의 경로.

is_package(fullname)

path가 패키지에 대한 것으로 드러나면 True를 반환합니다.

path_stats(path)

importlib.abc.SourceLoader.path_stats()의 구상 구현.

set_data(path, data)

importlib.abc.SourceLoader.set_data()의 구상 구현.

load_module(name=None)

로드할 모듈 이름을 지정하는 것이 선택적인 importlib.abc.Loader.load_module()의 구상 구현.

버전 3.6부터 폐지됨: 대신 importlib.abc.Loader.exec_module()을 사용하십시오.

class importlib.machinery.SourcelessFileLoader(fullname, path)

바이트 코드 파일을 (즉, 소스 코드 파일 없이) 임포트 할 수 있는 importlib.abc.FileLoader의 구상 구현.

바이트 코드 파일(그래서 소스 코드 파일이 아닌)을 직접 사용하면 모든 파이썬 구현이나 바이트 코드 형식을 변경하는 새 버전의 파이썬에서 모듈을 사용할 수 없게 됨에 유의하십시오.

Added in version 3.3.

name

로더가 처리할 모듈의 이름.

path

바이트 코드 파일의 경로.

is_package(fullname)

path를 기반으로 모듈이 패키지인지 판단합니다.

get_code(fullname)

path에서 만들어진 name의 코드 객체를 반환합니다.

get_source(fullname)

이 로더가 사용될 때는 바이트 코드 파일에 소스가 없어서 None을 반환합니다.

load_module(name=None)

로드할 모듈 이름을 지정하는 것이 선택적인 importlib.abc.Loader.load_module()의 구상 구현.

버전 3.6부터 폐지됨: 대신 importlib.abc.Loader.exec_module()을 사용하십시오.

class importlib.machinery.ExtensionFileLoader(fullname, path)

확장 모듈을 위한 importlib.abc.ExecutionLoader의 구상 구현.

fullname 인자는 로더가 지원할 모듈의 이름을 지정합니다. path 인자는 확장 모듈 파일의 경로입니다.

Note that, by default, importing an extension module will fail in subinterpreters if it doesn’t implement multi-phase init (see PEP 489 [https://peps.python.org/pep-0489/]), even if it would otherwise import successfully.

Added in version 3.3.

버전 3.12에서 변경: Multi-phase init is now required for use in subinterpreters.

name

로더가 지원하는 모듈의 이름.

path

확장 모듈의 경로.

create_module(spec)

PEP 489 [https://peps.python.org/pep-0489/]에 따라 지정된 명세에서 모듈 객체를 만듭니다.

Added in version 3.5.

exec_module(module)

PEP 489 [https://peps.python.org/pep-0489/]에 따라 주어진 모듈 객체를 초기화합니다.

Added in version 3.5.

is_package(fullname)

EXTENSION_SUFFIXES에 기반해서 파일 경로가 패키지의 __init__ 모듈을 가리키면 True를 반환합니다.

get_code(fullname)

확장 모듈에는 코드 객체가 없어서 None을 반환합니다.

get_source(fullname)

확장 모듈에는 소스 코드가 없어서 None을 반환합니다.

get_filename(fullname)

path를 반환합니다.

Added in version 3.4.

class importlib.machinery.NamespaceLoader(name, path, path_finder)

A concrete implementation of importlib.abc.InspectLoader for namespace packages. This is an alias for a private class and is only made public for introspecting the __loader__ attribute on namespace packages:

>>> from importlib.machinery import NamespaceLoader
>>> import my_namespace
>>> isinstance(my_namespace.__loader__, NamespaceLoader)
True
>>> import importlib.abc
>>> isinstance(my_namespace.__loader__, importlib.abc.Loader)
True

Added in version 3.11.

class importlib.machinery.ModuleSpec(name, loader, *, origin=None, loader_state=None, is_package=None)

A specification for a module’s import-system-related state. This is typically exposed as the module’s __spec__ attribute. Many of these attributes are also available directly on a module: for example, module.__spec__.origin == module.__file__. Note, however, that while the values are usually equivalent, they can differ since there is no synchronization between the two objects. For example, it is possible to update the module’s __file__ at runtime and this will not be automatically reflected in the module’s __spec__.origin, and vice versa.

Added in version 3.4.

name

The module’s fully qualified name (see module.__name__). The finder should always set this attribute to a non-empty string.

loader

The loader used to load the module (see module.__loader__). The finder should always set this attribute.

origin

The location the loader should use to load the module (see module.__file__). For example, for modules loaded from a .py file this is the filename. The finder should always set this attribute to a meaningful value for the loader to use. In the uncommon case that there is not one (like for namespace packages), it should be set to None.

submodule_search_locations

A (possibly empty) sequence of strings enumerating the locations in which a package’s submodules will be found (see module.__path__). Most of the time there will only be a single directory in this list.

The finder should set this attribute to a sequence, even an empty one, to indicate to the import system that the module is a package. It should be set to None for non-package modules. It is set automatically later to a special object for namespace packages.

loader_state

The finder may set this attribute to an object containing additional, module-specific data to use when loading the module. Otherwise it should be set to None.

cached

The filename of a compiled version of the module’s code (see module.__cached__). The finder should always set this attribute but it may be None for modules that do not need compiled code stored.

parent

(Read-only) The fully qualified name of the package the module is in (or the empty string for a top-level module). See module.__package__. If the module is a package then this is the same as name.

has_location

True if the spec’s origin refers to a loadable location, False otherwise. This value impacts how origin is interpreted and how the module’s __file__ is populated.

class importlib.machinery.AppleFrameworkLoader(name, path)

A specialization of importlib.machinery.ExtensionFileLoader that is able to load extension modules in Framework format.

For compatibility with the iOS App Store, all binary modules in an iOS app must be dynamic libraries, contained in a framework with appropriate metadata, stored in the Frameworks folder of the packaged app. There can be only a single binary per framework, and there can be no executable binary material outside the Frameworks folder.

To accommodate this requirement, when running on iOS, extension module binaries are not packaged as .so files on sys.path, but as individual standalone frameworks. To discover those frameworks, this loader is be registered against the .fwork file extension, with a .fwork file acting as a placeholder in the original location of the binary on sys.path. The .fwork file contains the path of the actual binary in the Frameworks folder, relative to the app bundle. To allow for resolving a framework-packaged binary back to the original location, the framework is expected to contain a .origin file that contains the location of the .fwork file, relative to the app bundle.

For example, consider the case of an import from foo.bar import _whiz, where _whiz is implemented with the binary module sources/foo/bar/_whiz.abi3.so, with sources being the location registered on sys.path, relative to the application bundle. This module must be distributed as Frameworks/foo.bar._whiz.framework/foo.bar._whiz (creating the framework name from the full import path of the module), with an Info.plist file in the .framework directory identifying the binary as a framework. The foo.bar._whiz module would be represented in the original location with a sources/foo/bar/_whiz.abi3.fwork marker file, containing the path Frameworks/foo.bar._whiz/foo.bar._whiz. The framework would also contain Frameworks/foo.bar._whiz.framework/foo.bar._whiz.origin, containing the path to the .fwork file.

When a module is loaded with this loader, the __file__ for the module will report as the location of the .fwork file. This allows code to use the __file__ of a module as an anchor for file system traversal. However, the spec origin will reference the location of the actual binary in the .framework folder.

The Xcode project building the app is responsible for converting any .so files from wherever they exist in the PYTHONPATH into frameworks in the Frameworks folder (including stripping extensions from the module file, the addition of framework metadata, and signing the resulting framework), and creating the .fwork and .origin files. This will usually be done with a build step in the Xcode project; see the iOS documentation for details on how to construct this build step.

Added in version 3.13.

Availability: iOS.

name

로더가 지원하는 모듈의 이름.

path

Path to the .fwork file for the extension module.

importlib.util – 임포터를 위한 유틸리티 코드

소스 코드: Lib/importlib/util.py [https://github.com/python/cpython/tree/main/Lib/importlib/util.py]

이 모듈에는 임포터 구성에 도움이 되는 다양한 객체가 포함되어 있습니다.

importlib.util.MAGIC_NUMBER

바이트 코드 버전 번호를 나타내는 바이트열. 바이트 코드의 로드/쓰기에 도움이 필요하면 importlib.abc.SourceLoader를 고려하십시오.

Added in version 3.4.

importlib.util.cache_from_source(path, debug_override=None, *, optimization=None)

소스 path와 연관된 바이트 컴파일된 파일의 PEP 3147 [https://peps.python.org/pep-3147/]/PEP 488 [https://peps.python.org/pep-0488/] 경로를 반환합니다. 예를 들어, path가 /foo/bar/baz.py이면 반환값은 파이썬 3.2의 경우 /foo/bar/__pycache__/baz.cpython-32.pyc입니다. cpython-32 문자열은 현재 매직 태그에서 온 것입니다 (get_tag()를 참조하십시오; sys.implementation.cache_tag가 정의되지 않으면 NotImplementedError 가 발생합니다).

optimization 매개 변수는 바이트 코드 파일의 최적화 수준을 지정하는 데 사용됩니다. 빈 문자열은 최적화하지 않음을 나타내므로, optimization이 '' 인 /foo/bar/baz.py는 바이트 코드 경로가 /foo/bar/__pycache__/baz.cpython-32.pyc가 됩니다. None은 인터프리터의 최적화 수준이 사용되도록 합니다. 다른 값의 문자열 표현은 사용되므로, optimization이 2인 /foo/bar/baz.py는 바이트 코드 경로가 /foo/bar/__pycache__/baz.cpython-32.opt-2.pyc가 됩니다. optimization의 문자열 표현은 영숫자만 가능하며, 그렇지 않으면 ValueError가 발생합니다.

debug_override 매개 변수는 폐지되었고 __debug__의 시스템값을 대체하는 데 사용할 수 있습니다. True 값은 optimization을 빈 문자열로 설정하는 것과 등등합니다. False 값은 optimization을 1로 설정하는 것과 같습니다. debug_override와 optimization이 모두 None이 아니면 TypeError가 발생합니다.

Added in version 3.4.

버전 3.5에서 변경: optimization 매개 변수가 추가되었고 debug_override 매개 변수는 폐지되었습니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

importlib.util.source_from_cache(path)

path에 PEP 3147 [https://peps.python.org/pep-3147/] 파일 이름이 주어지면, 연관된 소스 코드 파일 경로를 반환합니다. 예를 들어, path가 /foo/bar/__pycache__/baz.cpython-32.pyc이면 반환된 경로는 /foo/bar/baz.py입니다. path는 존재할 필요는 없지만, PEP 3147 [https://peps.python.org/pep-3147/]이나 PEP 488 [https://peps.python.org/pep-0488/] 형식을 준수하지 않으면, ValueError가 발생합니다. sys.implementation.cache_tag가 정의되지 않으면, NotImplementedError 가 발생합니다.

Added in version 3.4.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

importlib.util.decode_source(source_bytes)

소스 코드를 나타내는 주어진 바이트열을 디코딩하고 유니버설 줄 넘김이 적용된 문자열로 반환합니다 (importlib.abc.InspectLoader.get_source()에 필요한 대로).

Added in version 3.4.

importlib.util.resolve_name(name, package)

상대 모듈 이름을 절대 이름으로 결정합니다.

name 선두에 점이 없으면, name이 단순히 반환됩니다. 이를 통해 package 인자가 필요한지 확인하지 않고 importlib.util.resolve_name('sys', __spec__.parent)와 같은 사용이 가능합니다.

ImportError is raised if name is a relative module name but package is a false value (e.g. None or the empty string). ImportError is also raised if a relative name would escape its containing package (e.g. requesting ..bacon from within the spam package).

Added in version 3.3.

버전 3.9에서 변경: import 문과의 일관성을 개선하기 위해, 잘못된 상대 임포트 시도에 대해 ValueError 대신 ImportError를 발생시킵니다.

importlib.util.find_spec(name, package=None)

Find the spec for a module, optionally relative to the specified package name. If the module is in sys.modules, then sys.modules[name].__spec__ is returned (unless the spec would be None or is not set, in which case ValueError is raised). Otherwise a search using sys.meta_path is done. None is returned if no spec is found.

name이 서브 모듈에 관한 것이면 (점을 포함하면), 부모 모듈은 자동으로 임포트 됩니다.

name과 package는 import_module()과 같게 작동합니다.

Added in version 3.4.

버전 3.7에서 변경: Raises ModuleNotFoundError instead of AttributeError if package is in fact not a package (i.e. lacks a __path__ attribute).

importlib.util.module_from_spec(spec)

spec과 spec.loader.create_module을 기반으로 새 모듈을 만듭니다.

spec.loader.create_module이 None을 반환하지 않으면, 어떤 기존 어트리뷰트도 재설정되지 않습니다. 또한 spec에 액세스하거나 모듈에서 어트리뷰트를 설정하는 동안 트리거 되면 AttributeError가 발생하지 않습니다.

spec은 모듈에서 가능한 많은 임포트 제어 어트리뷰트를 설정하는 데 사용되므로 새 모듈을 작성하는 데 types.ModuleType을 사용하는 것보다 이 함수가 선호됩니다.

Added in version 3.5.

importlib.util.spec_from_loader(name, loader, *, origin=None, is_package=None)

A factory function for creating a ModuleSpec instance based on a loader. The parameters have the same meaning as they do for ModuleSpec. The function uses available loader APIs, such as InspectLoader.is_package(), to fill in any missing information on the spec.

Added in version 3.4.

importlib.util.spec_from_file_location(name, location, *, loader=None, submodule_search_locations=None)

A factory function for creating a ModuleSpec instance based on the path to a file. Missing information will be filled in on the spec by making use of loader APIs and by the implication that the module will be file-based.

Added in version 3.4.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

importlib.util.source_hash(source_bytes)

source_bytes의 해시를 바이트열로 반환합니다. 해시 기반 .pyc 파일은 해당 소스 파일 내용의 source_hash()를 헤더에 포함합니다.

Added in version 3.7.

importlib.util._incompatible_extension_module_restrictions(*, disable_check)

A context manager that can temporarily skip the compatibility check for extension modules. By default the check is enabled and will fail when a single-phase init module is imported in a subinterpreter. It will also fail for a multi-phase init module that doesn’t explicitly support a per-interpreter GIL, when imported in an interpreter with its own GIL.

Note that this function is meant to accommodate an unusual case; one which is likely to eventually go away. There’s is a pretty good chance this is not what you were looking for.

You can get the same effect as this function by implementing the basic interface of multi-phase init (PEP 489 [https://peps.python.org/pep-0489/]) and lying about support for multiple interpreters (or per-interpreter GIL).

경고

Using this function to disable the check can lead to unexpected behavior and even crashes. It should only be used during extension module development.

Added in version 3.12.

class importlib.util.LazyLoader(loader)

모듈이 어트리뷰트에 액세스할 때까지 모듈 로더의 실행을 연기하는 클래스.

This class only works with loaders that define exec_module() as control over what module type is used for the module is required. For those same reasons, the loader’s create_module() method must return None or a type for which its __class__ attribute can be mutated along with not using slots. Finally, modules which substitute the object placed into sys.modules will not work as there is no way to properly replace the module references throughout the interpreter safely; ValueError is raised if such a substitution is detected.

참고

시작 시간이 중요한 프로젝트의 경우, 이 클래스를 사용하면 사용하지 않을 모듈을 로드하는 데 드는 비용을 최소화할 수 있습니다. 시작 시간이 핵심이 아닌 프로젝트의 경우 로딩이 지연되는 동안 만들어진, 따라서 문맥을 벗어난 에러 메시지 때문에, 이 클래스를 사용하지 말 것을 강하게 권고합니다.

Added in version 3.5.

버전 3.6에서 변경: importlib.machinery.BuiltinImporter와 importlib.machinery.ExtensionFileLoader 에 대한 호환성 경고를 제거하고, create_module()을 호출하기 시작했습니다.

classmethod factory(loader)

A class method which returns a callable that creates a lazy loader. This is meant to be used in situations where the loader is passed by class instead of by instance.

suffixes = importlib.machinery.SOURCE_SUFFIXES
loader = importlib.machinery.SourceFileLoader
lazy_loader = importlib.util.LazyLoader.factory(loader)
finder = importlib.machinery.FileFinder(path, (lazy_loader, suffixes))

예

프로그래밍 방식으로 임포트 하기

프로그래밍 방식으로 모듈을 임포트 하려면, importlib.import_module()을 사용하십시오.

import importlib

itertools = importlib.import_module('itertools')

모듈을 임포트 할 수 있는지 확인하기

If you need to find out if a module can be imported without actually doing the import, then you should use importlib.util.find_spec().

Note that if name is a submodule (contains a dot), importlib.util.find_spec() will import the parent module.

import importlib.util
import sys

# For illustrative purposes.
name = 'itertools'

if name in sys.modules:
    print(f"{name!r} already in sys.modules")
elif (spec := importlib.util.find_spec(name)) is not None:
    # If you chose to perform the actual import ...
    module = importlib.util.module_from_spec(spec)
    sys.modules[name] = module
    spec.loader.exec_module(module)
    print(f"{name!r} has been imported")
else:
    print(f"can't find the {name!r} module")

소스 파일을 직접 임포트 하기

This recipe should be used with caution: it is an approximation of an import statement where the file path is specified directly, rather than sys.path being searched. Alternatives should first be considered first, such as modifying sys.path when a proper module is required, or using runpy.run_path() when the global namespace resulting from running a Python file is appropriate.

To import a Python source file directly from a path, use the following recipe:

import importlib.util
import sys

def import_from_path(module_name, file_path):
    spec = importlib.util.spec_from_file_location(module_name, file_path)
    module = importlib.util.module_from_spec(spec)
    sys.modules[module_name] = module
    spec.loader.exec_module(module)
    return module

# For illustrative purposes only (use of `json` is arbitrary).
import json
file_path = json.__file__
module_name = json.__name__

# Similar outcome as `import json`.
json = import_from_path(module_name, file_path)

Implementing lazy imports

The example below shows how to implement lazy imports:

>>> import importlib.util
>>> import sys
>>> def lazy_import(name):
...     spec = importlib.util.find_spec(name)
...     loader = importlib.util.LazyLoader(spec.loader)
...     spec.loader = loader
...     module = importlib.util.module_from_spec(spec)
...     sys.modules[name] = module
...     loader.exec_module(module)
...     return module
...
>>> lazy_typing = lazy_import("typing")
>>> #lazy_typing is a real module object,
>>> #but it is not loaded in memory yet.
>>> lazy_typing.TYPE_CHECKING
False

임포터 설정하기

For deep customizations of import, you typically want to implement an importer. This means managing both the finder and loader side of things. For finders there are two flavours to choose from depending on your needs: a meta path finder or a path entry finder. The former is what you would put on sys.meta_path while the latter is what you create using a path entry hook on sys.path_hooks which works with sys.path entries to potentially create a finder. This example will show you how to register your own importers so that import will use them (for creating an importer for yourself, read the documentation for the appropriate classes defined within this package):

import importlib.machinery
import sys

# For illustrative purposes only.
SpamMetaPathFinder = importlib.machinery.PathFinder
SpamPathEntryFinder = importlib.machinery.FileFinder
loader_details = (importlib.machinery.SourceFileLoader,
                  importlib.machinery.SOURCE_SUFFIXES)

# Setting up a meta path finder.
# Make sure to put the finder in the proper location in the list in terms of
# priority.
sys.meta_path.append(SpamMetaPathFinder)

# Setting up a path entry finder.
# Make sure to put the path hook in the proper location in the list in terms
# of priority.
sys.path_hooks.append(SpamPathEntryFinder.path_hook(loader_details))

importlib.import_module() 근사하기

Import itself is implemented in Python code, making it possible to expose most of the import machinery through importlib. The following helps illustrate the various APIs that importlib exposes by providing an approximate implementation of importlib.import_module():

import importlib.util
import sys

def import_module(name, package=None):
    """An approximate implementation of import."""
    absolute_name = importlib.util.resolve_name(name, package)
    try:
        return sys.modules[absolute_name]
    except KeyError:
        pass

    path = None
    if '.' in absolute_name:
        parent_name, _, child_name = absolute_name.rpartition('.')
        parent_module = import_module(parent_name)
        path = parent_module.__spec__.submodule_search_locations
    for finder in sys.meta_path:
        spec = finder.find_spec(absolute_name, path)
        if spec is not None:
            break
    else:
        msg = f'No module named {absolute_name!r}'
        raise ModuleNotFoundError(msg, name=absolute_name)
    module = importlib.util.module_from_spec(spec)
    sys.modules[absolute_name] = module
    spec.loader.exec_module(module)
    if path is not None:
        setattr(parent_module, child_name, module)
    return module

importlib.resources – Package resource reading, opening and access

Source code: Lib/importlib/resources/__init__.py [https://github.com/python/cpython/tree/main/Lib/importlib/resources/__init__.py]

Added in version 3.7.

This module leverages Python’s import system to provide access to resources within packages.

“Resources” are file-like resources associated with a module or package in Python. The resources may be contained directly in a package, within a subdirectory contained in that package, or adjacent to modules outside a package. Resources may be text or binary. As a result, Python module sources (.py) of a package and compilation artifacts (pycache) are technically de-facto resources of that package. In practice, however, resources are primarily those non-Python artifacts exposed specifically by the package author.

Resources can be opened or read in either binary or text mode.

Resources are roughly akin to files inside directories, though it’s important to keep in mind that this is just a metaphor. Resources and packages do not have to exist as physical files and directories on the file system: for example, a package and its resources can be imported from a zip file using zipimport.

참고

This module provides functionality similar to pkg_resources [https://setuptools.readthedocs.io/en/latest/pkg_resources.html] Basic Resource Access [https://setuptools.readthedocs.io/en/latest/pkg_resources.html#basic-resource-access] without the performance overhead of that package. This makes reading resources included in packages easier, with more stable and consistent semantics.

The standalone backport of this module provides more information on using importlib.resources [https://importlib-resources.readthedocs.io/en/latest/using.html] and migrating from pkg_resources to importlib.resources [https://importlib-resources.readthedocs.io/en/latest/migration.html].

Loaders that wish to support resource reading should implement a get_resource_reader(fullname) method as specified by importlib.resources.abc.ResourceReader.

class importlib.resources.Anchor

Represents an anchor for resources, either a module object or a module name as a string. Defined as Union[str, ModuleType].

importlib.resources.files(anchor: Anchor | None = None)

Returns a Traversable object representing the resource container (think directory) and its resources (think files). A Traversable may contain other containers (think subdirectories).

anchor is an optional Anchor. If the anchor is a package, resources are resolved from that package. If a module, resources are resolved adjacent to that module (in the same package or the package root). If the anchor is omitted, the caller’s module is used.

Added in version 3.9.

버전 3.12에서 변경: package parameter was renamed to anchor. anchor can now be a non-package module and if omitted will default to the caller’s module. package is still accepted for compatibility but will raise a DeprecationWarning. Consider passing the anchor positionally or using importlib_resources >= 5.10 for a compatible interface on older Pythons.

importlib.resources.as_file(traversable)

Given a Traversable object representing a file or directory, typically from importlib.resources.files(), return a context manager for use in a with statement. The context manager provides a pathlib.Path object.

Exiting the context manager cleans up any temporary file or directory created when the resource was extracted from e.g. a zip file.

Use as_file when the Traversable methods (read_text, etc) are insufficient and an actual file or directory on the file system is required.

Added in version 3.9.

버전 3.12에서 변경: Added support for traversable representing a directory.

Functional API

A set of simplified, backwards-compatible helpers is available. These allow common operations in a single function call.

For all the following functions:

anchor is an Anchor, as in files(). Unlike in files, it may not be omitted.

path_names are components of a resource’s path name, relative to the anchor. For example, to get the text of resource named info.txt, use:

importlib.resources.read_text(my_module, "info.txt")

Like Traversable.joinpath, The individual components should use forward slashes (/) as path separators. For example, the following are equivalent:

importlib.resources.read_binary(my_module, "pics/painting.png")
importlib.resources.read_binary(my_module, "pics", "painting.png")

For backward compatibility reasons, functions that read text require an explicit encoding argument if multiple path_names are given. For example, to get the text of info/chapter1.txt, use:

importlib.resources.read_text(my_module, "info", "chapter1.txt",
                              encoding='utf-8')

importlib.resources.open_binary(anchor, *path_names)

Open the named resource for binary reading.

See the introduction for details on anchor and path_names.

This function returns a BinaryIO object, that is, a binary stream open for reading.

This function is roughly equivalent to:

files(anchor).joinpath(*path_names).open('rb')

버전 3.13에서 변경: Multiple path_names are accepted.

importlib.resources.open_text(anchor, *path_names, encoding='utf-8', errors='strict')

Open the named resource for text reading. By default, the contents are read as strict UTF-8.

See the introduction for details on anchor and path_names. encoding and errors have the same meaning as in built-in open().

For backward compatibility reasons, the encoding argument must be given explicitly if there are multiple path_names. This limitation is scheduled to be removed in Python 3.15.

This function returns a TextIO object, that is, a text stream open for reading.

This function is roughly equivalent to:

files(anchor).joinpath(*path_names).open('r', encoding=encoding)

버전 3.13에서 변경: Multiple path_names are accepted. encoding and errors must be given as keyword arguments.

importlib.resources.read_binary(anchor, *path_names)

Read and return the contents of the named resource as bytes.

See the introduction for details on anchor and path_names.

This function is roughly equivalent to:

files(anchor).joinpath(*path_names).read_bytes()

버전 3.13에서 변경: Multiple path_names are accepted.

importlib.resources.read_text(anchor, *path_names, encoding='utf-8', errors='strict')

Read and return the contents of the named resource as str. By default, the contents are read as strict UTF-8.

See the introduction for details on anchor and path_names. encoding and errors have the same meaning as in built-in open().

For backward compatibility reasons, the encoding argument must be given explicitly if there are multiple path_names. This limitation is scheduled to be removed in Python 3.15.

This function is roughly equivalent to:

files(anchor).joinpath(*path_names).read_text(encoding=encoding)

버전 3.13에서 변경: Multiple path_names are accepted. encoding and errors must be given as keyword arguments.

importlib.resources.path(anchor, *path_names)

Provides the path to the resource as an actual file system path. This function returns a context manager for use in a with statement. The context manager provides a pathlib.Path object.

Exiting the context manager cleans up any temporary files created, e.g. when the resource needs to be extracted from a zip file.

For example, the stat() method requires an actual file system path; it can be used like this:

with importlib.resources.path(anchor, "resource.txt") as fspath:
    result = fspath.stat()

See the introduction for details on anchor and path_names.

This function is roughly equivalent to:

as_file(files(anchor).joinpath(*path_names))

버전 3.13에서 변경: Multiple path_names are accepted. encoding and errors must be given as keyword arguments.

importlib.resources.is_resource(anchor, *path_names)

Return True if the named resource exists, otherwise False. This function does not consider directories to be resources.

See the introduction for details on anchor and path_names.

This function is roughly equivalent to:

files(anchor).joinpath(*path_names).is_file()

버전 3.13에서 변경: Multiple path_names are accepted.

importlib.resources.contents(anchor, *path_names)

Return an iterable over the named items within the package or path. The iterable returns names of resources (e.g. files) and non-resources (e.g. directories) as str. The iterable does not recurse into subdirectories.

See the introduction for details on anchor and path_names.

This function is roughly equivalent to:

for resource in files(anchor).joinpath(*path_names).iterdir():
    yield resource.name

버전 3.11부터 폐지됨: Prefer iterdir() as above, which offers more control over the results and richer functionality.

importlib.resources.abc – Abstract base classes for resources

Source code: Lib/importlib/resources/abc.py [https://github.com/python/cpython/tree/main/Lib/importlib/resources/abc.py]

Added in version 3.11.

class importlib.resources.abc.ResourceReader

Superseded by TraversableResources

An abstract base class to provide the ability to read resources.

From the perspective of this ABC, a resource is a binary artifact that is shipped within a package. Typically this is something like a data file that lives next to the __init__.py file of the package. The purpose of this class is to help abstract out the accessing of such data files so that it does not matter if the package and its data file(s) are stored e.g. in a zip file versus on the file system.

For any of methods of this class, a resource argument is expected to be a path-like object which represents conceptually just a file name. This means that no subdirectory paths should be included in the resource argument. This is because the location of the package the reader is for, acts as the “directory”. Hence the metaphor for directories and file names is packages and resources, respectively. This is also why instances of this class are expected to directly correlate to a specific package (instead of potentially representing multiple packages or a module).

Loaders that wish to support resource reading are expected to provide a method called get_resource_reader(fullname) which returns an object implementing this ABC’s interface. If the module specified by fullname is not a package, this method should return None. An object compatible with this ABC should only be returned when the specified module is a package.

Deprecated since version 3.12, removed in version 3.14: Use importlib.resources.abc.TraversableResources instead.

abstractmethod open_resource(resource)

Returns an opened, file-like object for binary reading of the resource.

If the resource cannot be found, FileNotFoundError is raised.

abstractmethod resource_path(resource)

Returns the file system path to the resource.

If the resource does not concretely exist on the file system, raise FileNotFoundError.

abstractmethod is_resource(name)

Returns True if the named name is considered a resource. FileNotFoundError is raised if name does not exist.

abstractmethod contents()

Returns an iterable of strings over the contents of the package. Do note that it is not required that all names returned by the iterator be actual resources, e.g. it is acceptable to return names for which is_resource() would be false.

Allowing non-resource names to be returned is to allow for situations where how a package and its resources are stored are known a priori and the non-resource names would be useful. For instance, returning subdirectory names is allowed so that when it is known that the package and resources are stored on the file system then those subdirectory names can be used directly.

The abstract method returns an iterable of no items.

class importlib.resources.abc.Traversable

An object with a subset of pathlib.Path methods suitable for traversing directories and opening files.

For a representation of the object on the file-system, use importlib.resources.as_file().

name

Abstract. The base name of this object without any parent references.

abstractmethod iterdir()

Yield Traversable objects in self.

abstractmethod is_dir()

Return True if self is a directory.

abstractmethod is_file()

Return True if self is a file.

abstractmethod joinpath(*pathsegments)

Traverse directories according to pathsegments and return the result as Traversable.

Each pathsegments argument may contain multiple names separated by forward slashes (/, posixpath.sep ). For example, the following are equivalent:

files.joinpath('subdir', 'subsuddir', 'file.txt')
files.joinpath('subdir/subsuddir/file.txt')

Note that some Traversable implementations might not be updated to the latest version of the protocol. For compatibility with such implementations, provide a single argument without path separators to each call to joinpath. For example:

files.joinpath('subdir').joinpath('subsubdir').joinpath('file.txt')

버전 3.11에서 변경: joinpath accepts multiple pathsegments, and these segments may contain forward slashes as path separators. Previously, only a single child argument was accepted.

abstractmethod __truediv__(child)

Return Traversable child in self. Equivalent to joinpath(child).

abstractmethod open(mode='r', *args, **kwargs)

mode may be ‘r’ or ‘rb’ to open as text or binary. Return a handle suitable for reading (same as pathlib.Path.open).

When opening as text, accepts encoding parameters such as those accepted by io.TextIOWrapper.

read_bytes()

Read contents of self as bytes.

read_text(encoding=None)

Read contents of self as text.

class importlib.resources.abc.TraversableResources

An abstract base class for resource readers capable of serving the importlib.resources.files() interface. Subclasses ResourceReader and provides concrete implementations of the ResourceReader’s abstract methods. Therefore, any loader supplying TraversableResources also supplies ResourceReader.

Loaders that wish to support resource reading are expected to implement this interface.

abstractmethod files()

Returns a importlib.resources.abc.Traversable object for the loaded package.

importlib.metadata – Accessing package metadata

Added in version 3.8.

버전 3.10에서 변경: importlib.metadata is no longer provisional.

Source code: Lib/importlib/metadata/__init__.py [https://github.com/python/cpython/tree/main/Lib/importlib/metadata/__init__.py]

importlib.metadata is a library that provides access to the metadata of an installed Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package], such as its entry points or its top-level names (Import Package [https://packaging.python.org/en/latest/glossary/#term-Import-Package]s, modules, if any). Built in part on Python’s import system, this library intends to replace similar functionality in the entry point API [https://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points] and metadata API [https://setuptools.readthedocs.io/en/latest/pkg_resources.html#metadata-api] of pkg_resources. Along with importlib.resources, this package can eliminate the need to use the older and less efficient pkg_resources package.

importlib.metadata operates on third-party distribution packages installed into Python’s site-packages directory via tools such as pip [https://pypi.org/project/pip/]. Specifically, it works with distributions with discoverable dist-info or egg-info directories, and metadata defined by the Core metadata specifications [https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata].

중요

These are not necessarily equivalent to or correspond 1:1 with the top-level import package names that can be imported inside Python code. One distribution package can contain multiple import packages (and single modules), and one top-level import package may map to multiple distribution packages if it is a namespace package. You can use packages_distributions() to get a mapping between them.

By default, distribution metadata can live on the file system or in zip archives on sys.path. Through an extension mechanism, the metadata can live almost anywhere.

더 보기

https://importlib-metadata.readthedocs.io/

The documentation for importlib_metadata, which supplies a backport of importlib.metadata. This includes an API reference [https://importlib-metadata.readthedocs.io/en/latest/api.html] for this module’s classes and functions, as well as a migration guide [https://importlib-metadata.readthedocs.io/en/latest/migration.html] for existing users of pkg_resources.

개요

Let’s say you wanted to get the version string for a Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package] you’ve installed using pip. We start by creating a virtual environment and installing something into it:

$ python -m venv example
$ source example/bin/activate
(example) $ python -m pip install wheel

다음을 실행하여 wheel에 대한 버전 문자열을 얻을 수 있습니다:

(example) $ python
>>> from importlib.metadata import version
>>> version('wheel')
'0.32.3'

You can also get a collection of entry points selectable by properties of the EntryPoint (typically ‘group’ or ‘name’), such as console_scripts, distutils.commands and others. Each group contains a collection of EntryPoint objects.

여러분은 배포 메타데이터를 얻을 수 있습니다:

>>> list(metadata('wheel'))
['Metadata-Version', 'Name', 'Version', 'Summary', 'Home-page', 'Author', 'Author-email', 'Maintainer', 'Maintainer-email', 'License', 'Project-URL', 'Project-URL', 'Project-URL', 'Keywords', 'Platform', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Requires-Python', 'Provides-Extra', 'Requires-Dist', 'Requires-Dist']

또한 배포의 버전 번호를 가져오고, 구성 파일을 나열하고, 배포의 요구사항 리스트를 얻을 수 있습니다.

exception importlib.metadata.PackageNotFoundError

Subclass of ModuleNotFoundError raised by several functions in this module when queried for a distribution package which is not installed in the current Python environment.

기능적 API

이 패키지는 공용 API를 통해 다음과 같은 기능을 제공합니다.

진입 지점

importlib.metadata.entry_points(**select_params)

Returns a EntryPoints instance describing entry points for the current environment. Any given keyword parameters are passed to the select() method for comparison to the attributes of the individual entry point definitions.

Note: it is not currently possible to query for entry points based on their EntryPoint.dist attribute (as different Distribution instances do not currently compare equal, even if they have the same attributes)

class importlib.metadata.EntryPoints

Details of a collection of installed entry points.

Also provides a .groups attribute that reports all identified entry point groups, and a .names attribute that reports all identified entry point names.

class importlib.metadata.EntryPoint

Details of an installed entry point.

Each EntryPoint instance has .name, .group, and .value attributes and a .load() method to resolve the value. There are also .module, .attr, and .extras attributes for getting the components of the .value attribute, and .dist for obtaining information regarding the distribution package that provides the entry point.

Query all entry points:

>>> eps = entry_points()

The entry_points() function returns a EntryPoints object, a collection of all EntryPoint objects with names and groups attributes for convenience:

>>> sorted(eps.groups)
['console_scripts', 'distutils.commands', 'distutils.setup_keywords', 'egg_info.writers', 'setuptools.installation']

EntryPoints has a select() method to select entry points matching specific properties. Select entry points in the console_scripts group:

>>> scripts = eps.select(group='console_scripts')

Equivalently, since entry_points() passes keyword arguments through to select:

>>> scripts = entry_points(group='console_scripts')

Pick out a specific script named “wheel” (found in the wheel project):

>>> 'wheel' in scripts.names
True
>>> wheel = scripts['wheel']

Equivalently, query for that entry point during selection:

>>> (wheel,) = entry_points(group='console_scripts', name='wheel')
>>> (wheel,) = entry_points().select(group='console_scripts', name='wheel')

Inspect the resolved entry point:

>>> wheel
EntryPoint(name='wheel', value='wheel.cli:main', group='console_scripts')
>>> wheel.module
'wheel.cli'
>>> wheel.attr
'main'
>>> wheel.extras
[]
>>> main = wheel.load()
>>> main
<function main at 0x103528488>

The group and name are arbitrary values defined by the package author and usually a client will wish to resolve all entry points for a particular group. Read the setuptools docs [https://setuptools.pypa.io/en/latest/userguide/entry_point.html] for more information on entry points, their definition, and usage.

버전 3.12에서 변경: The “selectable” entry points were introduced in importlib_metadata 3.6 and Python 3.10. Prior to those changes, entry_points accepted no parameters and always returned a dictionary of entry points, keyed by group. With importlib_metadata 5.0 and Python 3.12, entry_points always returns an EntryPoints object. See backports.entry_points_selectable [https://pypi.org/project/backports.entry_points_selectable/] for compatibility options.

버전 3.13에서 변경: EntryPoint objects no longer present a tuple-like interface (__getitem__()).

배포 메타데이터

importlib.metadata.metadata(distribution_name)

Return the distribution metadata corresponding to the named distribution package as a PackageMetadata instance.

Raises PackageNotFoundError if the named distribution package is not installed in the current Python environment.

class importlib.metadata.PackageMetadata

A concrete implementation of the PackageMetadata protocol [https://importlib-metadata.readthedocs.io/en/latest/api.html#importlib_metadata.PackageMetadata].

In addition to providing the defined protocol methods and attributes, subscripting the instance is equivalent to calling the get() method.

Every Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package] includes some metadata, which you can extract using the metadata() function:

>>> wheel_metadata = metadata('wheel')

The keys of the returned data structure name the metadata keywords, and the values are returned unparsed from the distribution metadata:

>>> wheel_metadata['Requires-Python']
'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'

PackageMetadata also presents a json attribute that returns all the metadata in a JSON-compatible form per PEP 566 [https://peps.python.org/pep-0566/]:

>>> wheel_metadata.json['requires_python']
'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'

The full set of available metadata is not described here. See the PyPA Core metadata specification [https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata] for additional details.

버전 3.10에서 변경: The Description is now included in the metadata when presented through the payload. Line continuation characters have been removed.

The json attribute was added.

배포 버전

importlib.metadata.version(distribution_name)

Return the installed distribution package version for the named distribution package.

Raises PackageNotFoundError if the named distribution package is not installed in the current Python environment.

The version() function is the quickest way to get a Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package]’s version number, as a string:

>>> version('wheel')
'0.32.3'

배포 파일

importlib.metadata.files(distribution_name)

Return the full set of files contained within the named distribution package.

Raises PackageNotFoundError if the named distribution package is not installed in the current Python environment.

Returns None if the distribution is found but the installation database records reporting the files associated with the distribuion package are missing.

class importlib.metadata.PackagePath

A pathlib.PurePath derived object with additional dist, size, and hash properties corresponding to the distribution package’s installation metadata for that file.

The files() function takes a Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package] name and returns all of the files installed by this distribution. Each file is reported as a PackagePath instance. For example:

>>> util = [p for p in files('wheel') if 'util.py' in str(p)][0]
>>> util
PackagePath('wheel/util.py')
>>> util.size
859
>>> util.dist
<importlib.metadata._hooks.PathDistribution object at 0x101e0cef0>
>>> util.hash
<FileHash mode: sha256 value: bYkw5oMccfazVCoYQwKkkemoVyMAFoR34mmKBx8R1NI>

일단 파일을 얻으면, 내용을 읽을 수도 있습니다:

>>> print(util.read_text())
import base64
import sys
...
def as_bytes(s):
    if isinstance(s, text_type):
        return s.encode('utf-8')
    return s

You can also use the locate() method to get the absolute path to the file:

>>> util.locate()
PosixPath('/home/gustav/example/lib/site-packages/wheel/util.py')

In the case where the metadata file listing files (RECORD or SOURCES.txt) is missing, files() will return None. The caller may wish to wrap calls to files() in always_iterable [https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.always_iterable] or otherwise guard against this condition if the target distribution is not known to have the metadata present.

배포 요구 사항

importlib.metadata.requires(distribution_name)

Return the declared dependency specifiers for the named distribution package.

Raises PackageNotFoundError if the named distribution package is not installed in the current Python environment.

To get the full set of requirements for a Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package], use the requires() function:

>>> requires('wheel')
["pytest (>=3.0.0) ; extra == 'test'", "pytest-cov ; extra == 'test'"]

Mapping import to distribution packages

importlib.metadata.packages_distributions()

Return a mapping from the top level module and import package names found via sys.meta_path to the names of the distribution packages (if any) that provide the corresponding files.

To allow for namespace packages (which may have members provided by multiple distribution packages), each top level import name maps to a list of distribution names rather than mapping directly to a single name.

A convenience method to resolve the Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package] name (or names, in the case of a namespace package) that provide each importable top-level Python module or Import Package [https://packaging.python.org/en/latest/glossary/#term-Import-Package]:

>>> packages_distributions()
{'importlib_metadata': ['importlib-metadata'], 'yaml': ['PyYAML'], 'jaraco': ['jaraco.classes', 'jaraco.functools'], ...}

Some editable installs, do not supply top-level names [https://github.com/pypa/packaging-problems/issues/609], and thus this function is not reliable with such installs.

Added in version 3.10.

배포

importlib.metadata.distribution(distribution_name)

Return a Distribution instance describing the named distribution package.

Raises PackageNotFoundError if the named distribution package is not installed in the current Python environment.

class importlib.metadata.Distribution

Details of an installed distribution package.

Note: different Distribution instances do not currently compare equal, even if they relate to the same installed distribution and accordingly have the same attributes.

While the module level API described above is the most common and convenient usage, you can get all of that information from the Distribution class. Distribution is an abstract object that represents the metadata for a Python Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package]. You can get the concreate Distribution subclass instance for an installed distribution package by calling the distribution() function:

>>> from importlib.metadata import distribution
>>> dist = distribution('wheel')
>>> type(dist)
<class 'importlib.metadata.PathDistribution'>

Thus, an alternative way to get the version number is through the Distribution instance:

>>> dist.version
'0.32.3'

There are all kinds of additional metadata available on Distribution instances:

>>> dist.metadata['Requires-Python']
'>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'
>>> dist.metadata['License']
'MIT'

For editable packages, an origin property may present PEP 610 [https://peps.python.org/pep-0610/] metadata:

>>> dist.origin.url
'file:///path/to/wheel-0.32.3.editable-py3-none-any.whl'

The full set of available metadata is not described here. See the PyPA Core metadata specification [https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata] for additional details.

Added in version 3.13: The .origin property was added.

Distribution Discovery

By default, this package provides built-in support for discovery of metadata for file system and zip file Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package]s. This metadata finder search defaults to sys.path, but varies slightly in how it interprets those values from how other import machinery does. In particular:

importlib.metadata does not honor bytes objects on sys.path.

importlib.metadata will incidentally honor pathlib.Path objects on sys.path even though such values will be ignored for imports.

Implementing Custom Providers

importlib.metadata address two API surfaces, one for consumers and another for providers. Most users are consumers, consuming metadata provided by the packages. There are other use-cases, however, where users wish to expose metadata through some other mechanism, such as alongside a custom importer. Such a use case calls for a custom provider.

Because Distribution Package [https://packaging.python.org/en/latest/glossary/#term-Distribution-Package] metadata is not available through sys.path searches, or package loaders directly, the metadata for a distribution is found through import system finders. To find a distribution package’s metadata, importlib.metadata queries the list of meta path finders on sys.meta_path.

The implementation has hooks integrated into the PathFinder, serving metadata for distribution packages found on the file system.

추상 클래스 importlib.abc.MetaPathFinder는 파이썬의 임포트 시스템에 의해 파인더가 기대하는 인터페이스를 정의합니다. importlib.metadata는 sys.meta_path의 파인더에서 선택적인 find_distributions 콜러블을 조회함으로써 이 프로토콜을 확장하고 이 확장된 인터페이스를 다음과 같은 추상 메서드를 정의하는 DistributionFinder 추상 베이스 클래스로 제공합니다:

@abc.abstractmethod
def find_distributions(context=DistributionFinder.Context()) -> Iterable[Distribution]:
    """Return an iterable of all Distribution instances capable of
    loading the metadata for packages for the indicated ``context``.
    """

The DistributionFinder.Context object provides .path and .name properties indicating the path to search and name to match and may supply other relevant context sought by the consumer.

In practice, to support finding distribution package metadata in locations other than the file system, subclass Distribution and implement the abstract methods. Then from a custom finder, return instances of this derived Distribution in the find_distributions() method.

Example

Imagine a custom finder that loads Python modules from a database:

class DatabaseImporter(importlib.abc.MetaPathFinder):
    def __init__(self, db):
        self.db = db

    def find_spec(self, fullname, target=None) -> ModuleSpec:
        return self.db.spec_from_name(fullname)

sys.meta_path.append(DatabaseImporter(connect_db(...)))

That importer now presumably provides importable modules from a database, but it provides no metadata or entry points. For this custom importer to provide metadata, it would also need to implement DistributionFinder:

from importlib.metadata import DistributionFinder

class DatabaseImporter(DistributionFinder):
    ...

    def find_distributions(self, context=DistributionFinder.Context()):
        query = dict(name=context.name) if context.name else {}
        for dist_record in self.db.query_distributions(query):
            yield DatabaseDistribution(dist_record)

In this way, query_distributions would return records for each distribution served by the database matching the query. For example, if requests-1.0 is in the database, find_distributions would yield a DatabaseDistribution for Context(name='requests') or Context(name=None).

For the sake of simplicity, this example ignores context.path. The path attribute defaults to sys.path and is the set of import paths to be considered in the search. A DatabaseImporter could potentially function without any concern for a search path. Assuming the importer does no partitioning, the “path” would be irrelevant. In order to illustrate the purpose of path, the example would need to illustrate a more complex DatabaseImporter whose behavior varied depending on sys.path/PYTHONPATH. In that case, the find_distributions should honor the context.path and only yield Distributions pertinent to that path.

DatabaseDistribution, then, would look something like:

class DatabaseDistribution(importlib.metadata.Distribution):
    def __init__(self, record):
        self.record = record

    def read_text(self, filename):
        """
        Read a file like "METADATA" for the current distribution.
        """
        if filename == "METADATA":
            return f"""Name: {self.record.name}
Version: {self.record.version}
"""
        if filename == "entry_points.txt":
            return "\n".join(
              f"""[{ep.group}]\n{ep.name}={ep.value}"""
              for ep in self.record.entry_points)

    def locate_file(self, path):
        raise RuntimeError("This distribution has no file system")

This basic implementation should provide metadata and entry points for packages served by the DatabaseImporter, assuming that the record supplies suitable .name, .version, and .entry_points attributes.

The DatabaseDistribution may also provide other metadata files, like RECORD (required for Distribution.files) or override the implementation of Distribution.files. See the source for more inspiration.

The initialization of the sys.path module search path

A module search path is initialized when Python starts. This module search path may be accessed at sys.path.

The first entry in the module search path is the directory that contains the input script, if there is one. Otherwise, the first entry is the current directory, which is the case when executing the interactive shell, a -c command, or -m module.

The PYTHONPATH environment variable is often used to add directories to the search path. If this environment variable is found then the contents are added to the module search path.

참고

PYTHONPATH will affect all installed Python versions/environments. Be wary of setting this in your shell profile or global environment variables. The site module offers more nuanced techniques as mentioned below.

The next items added are the directories containing standard Python modules as well as any extension modules that these modules depend on. Extension modules are .pyd files on Windows and .so files on other platforms. The directory with the platform-independent Python modules is called prefix. The directory with the extension modules is called exec_prefix.

The PYTHONHOME environment variable may be used to set the prefix and exec_prefix locations. Otherwise these directories are found by using the Python executable as a starting point and then looking for various ‘landmark’ files and directories. Note that any symbolic links are followed so the real Python executable location is used as the search starting point. The Python executable location is called home.

Once home is determined, the prefix directory is found by first looking for pythonmajorversionminorversion.zip (python311.zip). On Windows the zip archive is searched for in home and on Unix the archive is expected to be in lib. Note that the expected zip archive location is added to the module search path even if the archive does not exist. If no archive was found, Python on Windows will continue the search for prefix by looking for Lib\os.py. Python on Unix will look for lib/pythonmajorversion.minorversion/os.py (lib/python3.11/os.py). On Windows prefix and exec_prefix are the same, however on other platforms lib/pythonmajorversion.minorversion/lib-dynload (lib/python3.11/lib-dynload) is searched for and used as an anchor for exec_prefix. On some platforms lib may be lib64 or another value, see sys.platlibdir and PYTHONPLATLIBDIR.

Once found, prefix and exec_prefix are available at sys.base_prefix and sys.base_exec_prefix respectively.

If PYTHONHOME is not set, and a pyvenv.cfg file is found alongside the main executable, or in its parent directory, sys.prefix and sys.exec_prefix get set to the directory containing pyvenv.cfg, otherwise they are set to the same value as sys.base_prefix and sys.base_exec_prefix, respectively. This is used by Virtual Environments.

Finally, the site module is processed and site-packages directories are added to the module search path. A common way to customize the search path is to create sitecustomize or usercustomize modules as described in the site module documentation.

참고

Certain command line options may further affect path calculations. See -E, -I, -s and -S for further details.

버전 3.14에서 변경: sys.prefix and sys.exec_prefix are now set to the pyvenv.cfg directory during the path initialization. This was previously done by site, therefore affected by -S.

Virtual Environments

Virtual environments place a pyvenv.cfg file in their prefix, which causes sys.prefix and sys.exec_prefix to point to them, instead of the base installation.

The prefix and exec_prefix values of the base installation are available at sys.base_prefix and sys.base_exec_prefix.

As well as being used as a marker to identify virtual environments, pyvenv.cfg may also be used to configure the site initialization. Please refer to site’s virtual environments documentation.

참고

PYTHONHOME overrides the pyvenv.cfg detection.

참고

There are other ways how “virtual environments” could be implemented, this documentation referes implementations based on the pyvenv.cfg mechanism, such as venv. Most virtual environment implementations follow the model set by venv, but there may be exotic implementations that diverge from it.

_pth files

To completely override sys.path create a ._pth file with the same name as the shared library or executable (python._pth or python311._pth). The shared library path is always known on Windows, however it may not be available on other platforms. In the ._pth file specify one line for each path to add to sys.path. The file based on the shared library name overrides the one based on the executable, which allows paths to be restricted for any program loading the runtime if desired.

When the file exists, all registry and environment variables are ignored, isolated mode is enabled, and site is not imported unless one line in the file specifies import site. Blank paths and lines starting with # are ignored. Each path may be absolute or relative to the location of the file. Import statements other than to site are not permitted, and arbitrary code cannot be specified.

Note that .pth files (without leading underscore) will be processed normally by the site module when import site has been specified.

Embedded Python

If Python is embedded within another application Py_InitializeFromConfig() and the PyConfig structure can be used to initialize Python. The path specific details are described at Python Path Configuration.

더 보기

모듈 찾기 for detailed Windows notes.

유닉스 플랫폼에서 파이썬 사용하기 for Unix details.

파이썬 언어 서비스

파이썬은 파이썬 언어로 작업하는 데 도움이 되는 여러 모듈을 제공합니다. 이 모듈들은 토큰화, 구문 분석, 문법 분석, 바이트 코드 역 어셈블리 및 기타 다양한 기능을 지원합니다.

이 모듈들은 다음과 같습니다:

ast — Abstract Syntax Trees

추상 문법

노드 클래스

AST

_fields

_field_types

lineno

col_offset

end_lineno

end_col_offset

Root nodes

Module

Expression

Interactive

FunctionType

리터럴

Constant

FormattedValue

JoinedStr

List

Tuple

Set

Dict

변수

Name

Load

Store

Del

Starred

표현식

Expr

UnaryOp

UAdd

USub

Not

Invert

BinOp

Add

Sub

Mult

Div

FloorDiv

Mod

Pow

LShift

RShift

BitOr

BitXor

BitAnd

MatMult

BoolOp

And

Or

Compare

Eq

NotEq

Lt

LtE

Gt

GtE

Is

IsNot

In

NotIn

Call

keyword

IfExp

Attribute

NamedExpr

서브스크립팅

Subscript

Slice

컴프리헨션

ListComp

SetComp

GeneratorExp

DictComp

comprehension

문장

Assign

type_comment

AnnAssign

AugAssign

Raise

Assert

Delete

Pass

TypeAlias

임포트

Import

ImportFrom

alias

제어 흐름

If

For

type_comment

While

Break

Continue

Try

TryStar

ExceptHandler

With

type_comment

withitem

Pattern matching

Match

match_case

MatchValue

MatchSingleton

MatchSequence

MatchStar

MatchMapping

MatchClass

MatchAs

MatchOr

Type parameters

TypeVar

ParamSpec

TypeVarTuple

함수와 클래스 정의

FunctionDef

type_comment

Lambda

arguments

arg

type_comment

Return

Yield

YieldFrom

Global

Nonlocal

ClassDef

Async와 await

AsyncFunctionDef

Await

AsyncFor

AsyncWith

ast 도우미

parse()

unparse()

literal_eval()

get_docstring()

get_source_segment()

fix_missing_locations()

increment_lineno()

copy_location()

iter_fields()

iter_child_nodes()

walk()

NodeVisitor

visit()

generic_visit()

visit_Constant()

NodeTransformer

dump()

컴파일러 플래그

PyCF_ALLOW_TOP_LEVEL_AWAIT

PyCF_ONLY_AST

PyCF_OPTIMIZED_AST

PyCF_TYPE_COMMENTS

compare()

명령 줄 사용법

symtable — Access to the compiler’s symbol tables

심볼 테이블 생성하기

symtable()

심볼 테이블 검사하기

SymbolTableType

MODULE

FUNCTION

CLASS

ANNOTATION

TYPE_ALIAS

TYPE_PARAMETERS

TYPE_VARIABLE

SymbolTable

get_type()

get_id()

get_name()

get_lineno()

is_optimized()

is_nested()

has_children()

get_identifiers()

lookup()

get_symbols()

get_children()

Function

get_parameters()

get_locals()

get_globals()

get_nonlocals()

get_frees()

Class

get_methods()

Symbol

get_name()

is_referenced()

is_imported()

is_parameter()

is_type_parameter()

is_global()

is_nonlocal()

is_declared_global()

is_local()

is_annotated()

is_free()

is_free_class()

is_assigned()

is_comp_iter()

is_comp_cell()

is_namespace()

get_namespaces()

get_namespace()

Command-Line Usage

token — Constants used with Python parse trees

tok_name

ISTERMINAL()

ISNONTERMINAL()

ISEOF()

ENDMARKER

NAME

NUMBER

STRING

NEWLINE

INDENT

DEDENT

LPAR

RPAR

LSQB

RSQB

COLON

COMMA

SEMI

PLUS

MINUS

STAR

SLASH

VBAR

AMPER

LESS

GREATER

EQUAL

DOT

PERCENT

LBRACE

RBRACE

EQEQUAL

NOTEQUAL

LESSEQUAL

GREATEREQUAL

TILDE

CIRCUMFLEX

LEFTSHIFT

RIGHTSHIFT

DOUBLESTAR

PLUSEQUAL

MINEQUAL

STAREQUAL

SLASHEQUAL

PERCENTEQUAL

AMPEREQUAL

VBAREQUAL

CIRCUMFLEXEQUAL

LEFTSHIFTEQUAL

RIGHTSHIFTEQUAL

DOUBLESTAREQUAL

DOUBLESLASH

DOUBLESLASHEQUAL

AT

ATEQUAL

RARROW

ELLIPSIS

COLONEQUAL

EXCLAMATION

OP

TYPE_IGNORE

TYPE_COMMENT

SOFT_KEYWORD

FSTRING_START

FSTRING_MIDDLE

FSTRING_END

COMMENT

NL

ERRORTOKEN

N_TOKENS

NT_OFFSET

ENCODING

keyword — Testing for Python keywords

iskeyword()

kwlist

issoftkeyword()

softkwlist

tokenize — Tokenizer for Python source

입력 토큰화하기

tokenize()

generate_tokens()

untokenize()

detect_encoding()

open()

TokenError

명령 줄 사용법

예제

tabnanny — Detection of ambiguous indentation

check()

verbose

filename_only

NannyNag

process_tokens()

pyclbr — Python module browser support

readmodule()

readmodule_ex()

Function 객체

Function

file

module

name

lineno

parent

children

is_async

Class 객체

Class

file

module

name

lineno

parent

children

super

methods

py_compile — Compile Python source files

PyCompileError

compile()

PycInvalidationMode

TIMESTAMP

CHECKED_HASH

UNCHECKED_HASH

Command-Line Interface

compileall — Byte-compile Python libraries

명령 줄 사용

공용 함수

compile_dir()

compile_file()

compile_path()

dis — Disassembler for Python bytecode

Command-line interface

바이트 코드 분석

Bytecode

from_traceback()

codeobj

first_line

dis()

info()

분석 함수

code_info()

show_code()

dis()

distb()

disassemble()

disco()

get_instructions()

findlinestarts()

findlabels()

stack_effect()

파이썬 바이트 코드 명령어

Instruction

opcode

opname

baseopcode

baseopname

arg

oparg

argval

argrepr

offset

start_offset

cache_offset

end_offset

starts_line

line_number

is_jump_target

jump_target

positions

Positions

lineno

end_lineno

col_offset

end_col_offset

옵코드 모음

opname

opmap

cmp_op

hasarg

hasconst

hasfree

hasname

hasjump

haslocal

hascompare

hasexc

hasjrel

hasjabs

pickletools — Tools for pickle developers

명령 줄 사용법

명령 줄 옵션

프로그래밍 인터페이스

dis()

genops()

optimize()

ast — Abstract Syntax Trees

소스 코드: Lib/ast.py [https://github.com/python/cpython/tree/main/Lib/ast.py]

ast 모듈은 파이썬 응용 프로그램이 파이썬 추상 구문 문법의 트리를 처리하는 데 도움을 줍니다. 추상 구문 자체는 각 파이썬 릴리스마다 바뀔 수 있습니다; 이 모듈은 프로그래밍 방식으로 현재 문법의 모양을 찾는 데 도움이 됩니다.

ast.PyCF_ONLY_AST를 플래그로 compile() 내장 함수에 전달하거나, 이 모듈에서 제공된 parse() 도우미를 사용하여 추상 구문 트리를 생성할 수 있습니다. 결과는 클래스가 모두 ast.AST에서 상속되는 객체들의 트리가 됩니다. 내장 compile() 함수를 사용하여 추상 구문 트리를 파이썬 코드 객체로 컴파일할 수 있습니다.

추상 문법

추상 문법은 현재 다음과 같이 정의됩니다:

-- ASDL's 4 builtin types are:
-- identifier, int, string, constant

module Python
{
    mod = Module(stmt* body, type_ignore* type_ignores)
        | Interactive(stmt* body)
        | Expression(expr body)
        | FunctionType(expr* argtypes, expr returns)

    stmt = FunctionDef(identifier name, arguments args,
                       stmt* body, expr* decorator_list, expr? returns,
                       string? type_comment, type_param* type_params)
          | AsyncFunctionDef(identifier name, arguments args,
                             stmt* body, expr* decorator_list, expr? returns,
                             string? type_comment, type_param* type_params)

          | ClassDef(identifier name,
             expr* bases,
             keyword* keywords,
             stmt* body,
             expr* decorator_list,
             type_param* type_params)
          | Return(expr? value)

          | Delete(expr* targets)
          | Assign(expr* targets, expr value, string? type_comment)
          | TypeAlias(expr name, type_param* type_params, expr value)
          | AugAssign(expr target, operator op, expr value)
          -- 'simple' indicates that we annotate simple name without parens
          | AnnAssign(expr target, expr annotation, expr? value, int simple)

          -- use 'orelse' because else is a keyword in target languages
          | For(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
          | AsyncFor(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
          | While(expr test, stmt* body, stmt* orelse)
          | If(expr test, stmt* body, stmt* orelse)
          | With(withitem* items, stmt* body, string? type_comment)
          | AsyncWith(withitem* items, stmt* body, string? type_comment)

          | Match(expr subject, match_case* cases)

          | Raise(expr? exc, expr? cause)
          | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
          | TryStar(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
          | Assert(expr test, expr? msg)

          | Import(alias* names)
          | ImportFrom(identifier? module, alias* names, int? level)

          | Global(identifier* names)
          | Nonlocal(identifier* names)
          | Expr(expr value)
          | Pass | Break | Continue

          -- col_offset is the byte offset in the utf8 string the parser uses
          attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

          -- BoolOp() can use left & right?
    expr = BoolOp(boolop op, expr* values)
         | NamedExpr(expr target, expr value)
         | BinOp(expr left, operator op, expr right)
         | UnaryOp(unaryop op, expr operand)
         | Lambda(arguments args, expr body)
         | IfExp(expr test, expr body, expr orelse)
         | Dict(expr* keys, expr* values)
         | Set(expr* elts)
         | ListComp(expr elt, comprehension* generators)
         | SetComp(expr elt, comprehension* generators)
         | DictComp(expr key, expr value, comprehension* generators)
         | GeneratorExp(expr elt, comprehension* generators)
         -- the grammar constrains where yield expressions can occur
         | Await(expr value)
         | Yield(expr? value)
         | YieldFrom(expr value)
         -- need sequences for compare to distinguish between
         -- x < 4 < 3 and (x < 4) < 3
         | Compare(expr left, cmpop* ops, expr* comparators)
         | Call(expr func, expr* args, keyword* keywords)
         | FormattedValue(expr value, int conversion, expr? format_spec)
         | JoinedStr(expr* values)
         | Constant(constant value, string? kind)

         -- the following expression can appear in assignment context
         | Attribute(expr value, identifier attr, expr_context ctx)
         | Subscript(expr value, expr slice, expr_context ctx)
         | Starred(expr value, expr_context ctx)
         | Name(identifier id, expr_context ctx)
         | List(expr* elts, expr_context ctx)
         | Tuple(expr* elts, expr_context ctx)

         -- can appear only in Subscript
         | Slice(expr? lower, expr? upper, expr? step)

          -- col_offset is the byte offset in the utf8 string the parser uses
          attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

    expr_context = Load | Store | Del

    boolop = And | Or

    operator = Add | Sub | Mult | MatMult | Div | Mod | Pow | LShift
                 | RShift | BitOr | BitXor | BitAnd | FloorDiv

    unaryop = Invert | Not | UAdd | USub

    cmpop = Eq | NotEq | Lt | LtE | Gt | GtE | Is | IsNot | In | NotIn

    comprehension = (expr target, expr iter, expr* ifs, int is_async)

    excepthandler = ExceptHandler(expr? type, identifier? name, stmt* body)
                    attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

    arguments = (arg* posonlyargs, arg* args, arg? vararg, arg* kwonlyargs,
                 expr* kw_defaults, arg? kwarg, expr* defaults)

    arg = (identifier arg, expr? annotation, string? type_comment)
           attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

    -- keyword arguments supplied to call (NULL identifier for **kwargs)
    keyword = (identifier? arg, expr value)
               attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

    -- import name with optional 'as' alias.
    alias = (identifier name, identifier? asname)
             attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

    withitem = (expr context_expr, expr? optional_vars)

    match_case = (pattern pattern, expr? guard, stmt* body)

    pattern = MatchValue(expr value)
            | MatchSingleton(constant value)
            | MatchSequence(pattern* patterns)
            | MatchMapping(expr* keys, pattern* patterns, identifier? rest)
            | MatchClass(expr cls, pattern* patterns, identifier* kwd_attrs, pattern* kwd_patterns)

            | MatchStar(identifier? name)
            -- The optional "rest" MatchMapping parameter handles capturing extra mapping keys

            | MatchAs(pattern? pattern, identifier? name)
            | MatchOr(pattern* patterns)

             attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)

    type_ignore = TypeIgnore(int lineno, string tag)

    type_param = TypeVar(identifier name, expr? bound, expr? default_value)
               | ParamSpec(identifier name, expr? default_value)
               | TypeVarTuple(identifier name, expr? default_value)
               attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)
}

노드 클래스

class ast.AST

This is the base of all AST node classes. The actual node classes are derived from the Parser/Python.asdl file, which is reproduced above. They are defined in the _ast C module and re-exported in ast.

추상 문법의 각 좌변 심볼마다 하나의 클래스가 정의되어 있습니다 (예를 들어, ast.stmt나 ast.expr). 또한, 우변의 생성자마다 하나의 클래스가 정의되어 있습니다; 이 클래스는 좌변 트리의 클래스에서 상속됩니다. 예를 들어, ast.BinOp는 ast.expr에서 상속됩니다. 대안을 갖는 생성 규칙(일명 “합”)의 경우, 좌변 클래스는 추상입니다: 특정 생성자 노드의 인스턴스만 만들어집니다.

_fields

Each concrete class has an attribute _fields which gives the names of all child nodes.

구상 클래스의 각 인스턴스에는 각 자식 노드마다 문법에 정의된 형의 어트리뷰트가 하나씩 있습니다. 예를 들어, ast.BinOp 인스턴스는 ast.expr 형의 어트리뷰트 left를 갖습니다.

문법에서 이러한 어트리뷰트가 선택적으로 표시되면 (물음표를 사용해서), 값은 None일 수 있습니다. 어트리뷰트가 0개 이상의 값을 가질 수 있으면 (애스터리스크로 표시됩니다), 값은 파이썬 리스트로 표현됩니다. compile()로 AST를 컴파일할 때 가능한 모든 어트리뷰트가 존재하고 유효한 값을 가져야 합니다.

_field_types

The _field_types attribute on each concrete class is a dictionary mapping field names (as also listed in _fields) to their types.

>>> ast.TypeVar._field_types
{'name': <class 'str'>, 'bound': ast.expr | None, 'default_value': ast.expr | None}

Added in version 3.13.

lineno

col_offset

end_lineno

end_col_offset

Instances of ast.expr and ast.stmt subclasses have lineno, col_offset, end_lineno, and end_col_offset attributes. The lineno and end_lineno are the first and last line numbers of source text span (1-indexed so the first line is line 1) and the col_offset and end_col_offset are the corresponding UTF-8 byte offsets of the first and last tokens that generated the node. The UTF-8 offset is recorded because the parser uses UTF-8 internally.

종료 위치는 컴파일러에 필요하지 않아서 선택 사항입니다. 종료 오프셋은 마지막 심볼 뒤입니다. 예를 들어 source_line[node.col_offset : node.end_col_offset]를 사용하여 한 줄 표현식 노드의 소스 세그먼트를 가져올 수 있습니다.

ast.T 클래스의 생성자는 다음과 같이 인자를 구문 분석합니다:

위치 인자가 있으면, T._fields에 있는 항목 수만큼 있어야 합니다; 이러한 이름의 어트리뷰트로 대입될 것입니다.

키워드 인자가 있으면, 같은 이름의 어트리뷰트를 지정된 값으로 설정합니다.

예를 들어, ast.UnaryOp 노드를 만들고 채우려면, 다음과 같이 할 수 있습니다

node = ast.UnaryOp(ast.USub(), ast.Constant(5, lineno=0, col_offset=0),
                   lineno=0, col_offset=0)

If a field that is optional in the grammar is omitted from the constructor, it defaults to None. If a list field is omitted, it defaults to the empty list. If a field of type ast.expr_context is omitted, it defaults to Load(). If any other field is omitted, a DeprecationWarning is raised and the AST node will not have this field. In Python 3.15, this condition will raise an error.

버전 3.8에서 변경: ast.Constant 클래스는 이제 모든 상수에 사용됩니다.

버전 3.9에서 변경: 단순 인덱스는 값으로 표현되고, 확장 슬라이스는 튜플로 표현됩니다.

버전 3.14에서 변경: The __repr__() output of AST nodes includes the values of the node fields.

버전 3.8부터 폐지됨: Old classes ast.Num, ast.Str, ast.Bytes, ast.NameConstant and ast.Ellipsis are still available, but they will be removed in future Python releases. In the meantime, instantiating them will return an instance of a different class.

버전 3.9부터 폐지됨: Old classes ast.Index and ast.ExtSlice are still available, but they will be removed in future Python releases. In the meantime, instantiating them will return an instance of a different class.

Deprecated since version 3.13, will be removed in version 3.15: Previous versions of Python allowed the creation of AST nodes that were missing required fields. Similarly, AST node constructors allowed arbitrary keyword arguments that were set as attributes of the AST node, even if they did not match any of the fields of the AST node. This behavior is deprecated and will be removed in Python 3.15.

참고

여기에 표시된 특정 노드 클래스에 대한 설명은 처음에는 환상적인 Green Tree Snakes [https://greentreesnakes.readthedocs.io/en/latest/] 프로젝트와 모든 기여자로부터 차용했습니다.

Root nodes

class ast.Module(body, type_ignores)

A Python module, as with file input. Node type generated by ast.parse() in the default "exec" mode.

body is a list of the module’s 문장.

type_ignores is a list of the module’s type ignore comments; see ast.parse() for more details.

>>> print(ast.dump(ast.parse('x = 1'), indent=4))
Module(
    body=[
        Assign(
            targets=[
                Name(id='x', ctx=Store())],
            value=Constant(value=1))])

class ast.Expression(body)

A single Python expression input. Node type generated by ast.parse() when mode is "eval".

body is a single node, one of the expression types.

>>> print(ast.dump(ast.parse('123', mode='eval'), indent=4))
Expression(
    body=Constant(value=123))

class ast.Interactive(body)

A single interactive input, like in 대화형 모드. Node type generated by ast.parse() when mode is "single".

body is a list of statement nodes.

>>> print(ast.dump(ast.parse('x = 1; y = 2', mode='single'), indent=4))
Interactive(
    body=[
        Assign(
            targets=[
                Name(id='x', ctx=Store())],
            value=Constant(value=1)),
        Assign(
            targets=[
                Name(id='y', ctx=Store())],
            value=Constant(value=2))])

class ast.FunctionType(argtypes, returns)

A representation of an old-style type comments for functions, as Python versions prior to 3.5 didn’t support PEP 484 [https://peps.python.org/pep-0484/] annotations. Node type generated by ast.parse() when mode is "func_type".

Such type comments would look like this:

def sum_two_number(a, b):
    # type: (int, int) -> int
    return a + b

argtypes is a list of expression nodes.

returns is a single expression node.

>>> print(ast.dump(ast.parse('(int, str) -> List[int]', mode='func_type'), indent=4))
FunctionType(
    argtypes=[
        Name(id='int', ctx=Load()),
        Name(id='str', ctx=Load())],
    returns=Subscript(
        value=Name(id='List', ctx=Load()),
        slice=Name(id='int', ctx=Load()),
        ctx=Load()))

Added in version 3.8.

리터럴

class ast.Constant(value)

상숫값. Constant 리터럴의 value 어트리뷰트는 그것이 나타내는 파이썬 객체를 포함합니다. 표현되는 값은 숫자, 문자열 또는 None과 같은 간단한 형일 수 있지만, 모든 요소가 상수라면 불변 컨테이너 형(튜플과 frozenset)일 수도 있습니다.

>>> print(ast.dump(ast.parse('123', mode='eval'), indent=4))
Expression(
    body=Constant(value=123))

class ast.FormattedValue(value, conversion, format_spec)

f-문자열에서 단일 포매팅 필드를 나타내는 노드. 문자열에 단일 포매팅 필드가 포함되어 있고 다른 것이 없으면 노드를 분리 할 수 있습니다, 그렇지 않으면 JoinedStr에 나타납니다.

value는 모든 표현식 노드(가령 리터럴, 변수 또는 함수 호출)입니다.

conversion은 정수입니다:

-1: 포매팅 없음

115: !s 문자열 포매팅

114: !r repr 포매팅

97: !a ascii 포매팅

format_spec은 값의 포매팅을 나타내는 JoinedStr 노드이거나, 표맷이 지정되지 않았으면 None입니다. conversion과 format_spec을 동시에 설정할 수 있습니다.

class ast.JoinedStr(values)

일련의 FormattedValue와 Constant 노드로 구성된 f-문자열.

>>> print(ast.dump(ast.parse('f"sin({a}) is {sin(a):.3}"', mode='eval'), indent=4))
Expression(
    body=JoinedStr(
        values=[
            Constant(value='sin('),
            FormattedValue(
                value=Name(id='a', ctx=Load()),
                conversion=-1),
            Constant(value=') is '),
            FormattedValue(
                value=Call(
                    func=Name(id='sin', ctx=Load()),
                    args=[
                        Name(id='a', ctx=Load())]),
                conversion=-1,
                format_spec=JoinedStr(
                    values=[
                        Constant(value='.3')]))]))

class ast.List(elts, ctx)

class ast.Tuple(elts, ctx)

리스트나 튜플. elts는 요소를 나타내는 노드의 리스트를 보유합니다. ctx는 컨테이너가 대입 대상이면 (가령 (x,y)=something) Store이고, 그렇지 않으면 Load입니다.

>>> print(ast.dump(ast.parse('[1, 2, 3]', mode='eval'), indent=4))
Expression(
    body=List(
        elts=[
            Constant(value=1),
            Constant(value=2),
            Constant(value=3)],
        ctx=Load()))
>>> print(ast.dump(ast.parse('(1, 2, 3)', mode='eval'), indent=4))
Expression(
    body=Tuple(
        elts=[
            Constant(value=1),
            Constant(value=2),
            Constant(value=3)],
        ctx=Load()))

class ast.Set(elts)

집합. elts는 집합의 요소를 나타내는 노드의 리스트를 보유합니다.

>>> print(ast.dump(ast.parse('{1, 2, 3}', mode='eval'), indent=4))
Expression(
    body=Set(
        elts=[
            Constant(value=1),
            Constant(value=2),
            Constant(value=3)]))

class ast.Dict(keys, values)

딕셔너리. keys와 values는 각각 키와 값을 나타내는 노드의 리스트를 일치하는 순서대로 (dictionary.keys()와 dictionary.values()를 호출할 때 반환되는 순서) 보유합니다.

딕셔너리 리터럴을 사용하여 딕셔너리 언 패킹을 수행할 때 확장될 표현식은 values 리스트로 가고, keys의 해당 위치에는 None이 갑니다.

>>> print(ast.dump(ast.parse('{"a":1, **d}', mode='eval'), indent=4))
Expression(
    body=Dict(
        keys=[
            Constant(value='a'),
            None],
        values=[
            Constant(value=1),
            Name(id='d', ctx=Load())]))

변수

class ast.Name(id, ctx)

변수 이름. id는 이름을 문자열로 보유하며, ctx는 다음 형 중 하나입니다.

class ast.Load

class ast.Store

class ast.Del

변수 참조는 변숫값을 로드하거나, 그것에 새 값을 대입하거나, 그것을 삭제하는데 사용될 수 있습니다. 변수 참조에는 이러한 경우를 구별하기 위한 컨텍스트가 제공됩니다.

>>> print(ast.dump(ast.parse('a'), indent=4))
Module(
    body=[
        Expr(
            value=Name(id='a', ctx=Load()))])

>>> print(ast.dump(ast.parse('a = 1'), indent=4))
Module(
    body=[
        Assign(
            targets=[
                Name(id='a', ctx=Store())],
            value=Constant(value=1))])

>>> print(ast.dump(ast.parse('del a'), indent=4))
Module(
    body=[
        Delete(
            targets=[
                Name(id='a', ctx=Del())])])

class ast.Starred(value, ctx)

*var 변수 참조. value는 변수(일반적으로 Name 노드)를 보유합니다. 이 형은 *args로 Call 노드를 빌드할 때 사용해야 합니다.

>>> print(ast.dump(ast.parse('a, *b = it'), indent=4))
Module(
    body=[
        Assign(
            targets=[
                Tuple(
                    elts=[
                        Name(id='a', ctx=Store()),
                        Starred(
                            value=Name(id='b', ctx=Store()),
                            ctx=Store())],
                    ctx=Store())],
            value=Name(id='it', ctx=Load()))])

표현식

class ast.Expr(value)

표현식(가령 함수 호출)이 반환 값이 사용되거나 저장되지 않은 자신만의 문장으로 나타나면, 이 컨테이너에 래핑 됩니다. value는 이 섹션의 다른 노드인 Constant, Name, Lambda, Yield 또는 YieldFrom 노드 중 하나를 보유합니다.

>>> print(ast.dump(ast.parse('-a'), indent=4))
Module(
    body=[
        Expr(
            value=UnaryOp(
                op=USub(),
                operand=Name(id='a', ctx=Load())))])

class ast.UnaryOp(op, operand)

단항 연산. op는 연산자이고, operand는 임의의 표현식 노드입니다.

class ast.UAdd

class ast.USub

class ast.Not

class ast.Invert

단항 연산자 토큰. Not은 not 키워드이고, Invert는 ~ 연산자입니다.

>>> print(ast.dump(ast.parse('not x', mode='eval'), indent=4))
Expression(
    body=UnaryOp(
        op=Not(),
        operand=Name(id='x', ctx=Load())))

class ast.BinOp(left, op, right)

이항 연산 (더하기나 나누기 같은). op는 연산자이고, left와 right는 임의의 표현식 노드입니다.

>>> print(ast.dump(ast.parse('x + y', mode='eval'), indent=4))
Expression(
    body=BinOp(
        left=Name(id='x', ctx=Load()),
        op=Add(),
        right=Name(id='y', ctx=Load())))

class ast.Add

class ast.Sub

class ast.Mult

class ast.Div

class ast.FloorDiv

class ast.Mod

class ast.Pow

class ast.LShift

class ast.RShift

class ast.BitOr

class ast.BitXor

class ast.BitAnd

class ast.MatMult

이항 연산자 토큰.

class ast.BoolOp(op, values)

불리언 연산, ‘or’ 나 ‘and’. op는 Or나 And입니다. values는 관련된 값입니다. 같은 연산자를 사용하는 연속 연산(가령 a or b or c)은 여러 값을 가진 하나의 노드로 축소됩니다.

여기에는 UnaryOp인 not이 포함되지 않습니다.

>>> print(ast.dump(ast.parse('x or y', mode='eval'), indent=4))
Expression(
    body=BoolOp(
        op=Or(),
        values=[
            Name(id='x', ctx=Load()),
            Name(id='y', ctx=Load())]))

class ast.And

class ast.Or

불리언 연산자 토큰.

class ast.Compare(left, ops, comparators)

둘 이상의 값의 비교. left는 비교의 첫 번째 값이고, ops는 연산자의 리스트이며, comparators는 비교의 첫 번째 요소 다음의 값 리스트입니다.

>>> print(ast.dump(ast.parse('1 <= a < 10', mode='eval'), indent=4))
Expression(
    body=Compare(
        left=Constant(value=1),
        ops=[
            LtE(),
            Lt()],
        comparators=[
            Name(id='a', ctx=Load()),
            Constant(value=10)]))

class ast.Eq

class ast.NotEq

class ast.Lt

class ast.LtE

class ast.Gt

class ast.GtE

class ast.Is

class ast.IsNot

class ast.In

class ast.NotIn

비교 연산자 토큰.

class ast.Call(func, args, keywords)

함수 호출. func는 함수이며, 종종 Name이나 Attribute 객체입니다. 인자 중:

args는 위치로 전달된 인자의 리스트를 보유합니다.

keywords holds a list of keyword objects representing arguments passed by keyword.

The args and keywords arguments are optional and default to empty lists.

>>> print(ast.dump(ast.parse('func(a, b=c, *d, **e)', mode='eval'), indent=4))
Expression(
    body=Call(
        func=Name(id='func', ctx=Load()),
        args=[
            Name(id='a', ctx=Load()),
            Starred(
                value=Name(id='d', ctx=Load()),
                ctx=Load())],
        keywords=[
            keyword(
                arg='b',
                value=Name(id='c', ctx=Load())),
            keyword(
                value=Name(id='e', ctx=Load()))]))

class ast.keyword(arg, value)

함수 호출이나 클래스 정의에 대한 키워드 인자. arg는 매개 변수 이름의 원시 문자열이고, value는 전달할 노드입니다.

class ast.IfExp(test, body, orelse)

a if b else c와 같은 표현식. 각 필드는 단일 노드를 보유해서, 다음 예에서, 세 개 모두 Name 노드입니다.

>>> print(ast.dump(ast.parse('a if b else c', mode='eval'), indent=4))
Expression(
    body=IfExp(
        test=Name(id='b', ctx=Load()),
        body=Name(id='a', ctx=Load()),
        orelse=Name(id='c', ctx=Load())))

class ast.Attribute(value, attr, ctx)

어트리뷰트 액세스, 예를 들어 d.keys. value는 노드(보통 Name)입니다. attr은 어트리뷰트의 이름을 제공하는 문자열이며, ctx는 어트리뷰트에 적용되는 방식에 따라 Load, Store 또는 Del입니다.

>>> print(ast.dump(ast.parse('snake.colour', mode='eval'), indent=4))
Expression(
    body=Attribute(
        value=Name(id='snake', ctx=Load()),
        attr='colour',
        ctx=Load()))

class ast.NamedExpr(target, value)

명명된 표현식. 이 AST 노드는 대입 표현식 연산자(바다코끼리(walrus) 연산자라고도 합니다)에 의해 생성됩니다. 첫 번째 인자가 여러 노드일 수 있는 Assign 노드와 달리, 이 경우에는 target과 value는 모두 단일 노드여야 합니다.

>>> print(ast.dump(ast.parse('(x := 4)', mode='eval'), indent=4))
Expression(
    body=NamedExpr(
        target=Name(id='x', ctx=Store()),
        value=Constant(value=4)))

Added in version 3.8.

서브스크립팅

class ast.Subscript(value, slice, ctx)

서브스크립트, 가령 l[1]. value는 서브스크립트되는 객체입니다 (보통 시퀀스나 매핑). slice는 인덱스, 슬라이스 또는 키입니다. Tuple일 수 있으며 Slice를 포함합니다. ctx는 서브스크립트로 수행되는 동작에 따라 Load, Store 또는 Del입니다.

>>> print(ast.dump(ast.parse('l[1:2, 3]', mode='eval'), indent=4))
Expression(
    body=Subscript(
        value=Name(id='l', ctx=Load()),
        slice=Tuple(
            elts=[
                Slice(
                    lower=Constant(value=1),
                    upper=Constant(value=2)),
                Constant(value=3)],
            ctx=Load()),
        ctx=Load()))

class ast.Slice(lower, upper, step)

일반 슬라이싱 (lower:upper나 lower:upper:step 형식). Subscript의 slice 필드 내에서만 직접 또는 Tuple의 요소로 등장할 수 있습니다.

>>> print(ast.dump(ast.parse('l[1:2]', mode='eval'), indent=4))
Expression(
    body=Subscript(
        value=Name(id='l', ctx=Load()),
        slice=Slice(
            lower=Constant(value=1),
            upper=Constant(value=2)),
        ctx=Load()))

컴프리헨션

class ast.ListComp(elt, generators)

class ast.SetComp(elt, generators)

class ast.GeneratorExp(elt, generators)

class ast.DictComp(key, value, generators)

리스트와 집합 컴프리헨션, 제너레이터 표현식 및 딕셔너리 컴프리헨션. elt(또는 key와 value)는 항목마다 평가될 부분을 나타내는 단일 노드입니다.

generators는 comprehension 노드의 리스트입니다.

>>> print(ast.dump(
...     ast.parse('[x for x in numbers]', mode='eval'),
...     indent=4,
... ))
Expression(
    body=ListComp(
        elt=Name(id='x', ctx=Load()),
        generators=[
            comprehension(
                target=Name(id='x', ctx=Store()),
                iter=Name(id='numbers', ctx=Load()),
                is_async=0)]))
>>> print(ast.dump(
...     ast.parse('{x: x**2 for x in numbers}', mode='eval'),
...     indent=4,
... ))
Expression(
    body=DictComp(
        key=Name(id='x', ctx=Load()),
        value=BinOp(
            left=Name(id='x', ctx=Load()),
            op=Pow(),
            right=Constant(value=2)),
        generators=[
            comprehension(
                target=Name(id='x', ctx=Store()),
                iter=Name(id='numbers', ctx=Load()),
                is_async=0)]))
>>> print(ast.dump(
...     ast.parse('{x for x in numbers}', mode='eval'),
...     indent=4,
... ))
Expression(
    body=SetComp(
        elt=Name(id='x', ctx=Load()),
        generators=[
            comprehension(
                target=Name(id='x', ctx=Store()),
                iter=Name(id='numbers', ctx=Load()),
                is_async=0)]))

class ast.comprehension(target, iter, ifs, is_async)

컴프리헨션에서 하나의 for 절. target은 각 요소(보통 Name이나 Tuple 노드)에 사용할 참조입니다. iter는 이터레이트 할 객체입니다. ifs는 테스트 표현식의 리스트입니다: 각 for 절은 여러 ifs를 가질 수 있습니다.

is_async는 컴프리헨션이 비동기임을 나타냅니다 (for 대신 async for를 사용합니다). 값은 정수(0이나 1)입니다.

>>> print(ast.dump(ast.parse('[ord(c) for line in file for c in line]', mode='eval'),
...                indent=4)) # Multiple comprehensions in one.
Expression(
    body=ListComp(
        elt=Call(
            func=Name(id='ord', ctx=Load()),
            args=[
                Name(id='c', ctx=Load())]),
        generators=[
            comprehension(
                target=Name(id='line', ctx=Store()),
                iter=Name(id='file', ctx=Load()),
                is_async=0),
            comprehension(
                target=Name(id='c', ctx=Store()),
                iter=Name(id='line', ctx=Load()),
                is_async=0)]))

>>> print(ast.dump(ast.parse('(n**2 for n in it if n>5 if n<10)', mode='eval'),
...                indent=4)) # generator comprehension
Expression(
    body=GeneratorExp(
        elt=BinOp(
            left=Name(id='n', ctx=Load()),
            op=Pow(),
            right=Constant(value=2)),
        generators=[
            comprehension(
                target=Name(id='n', ctx=Store()),
                iter=Name(id='it', ctx=Load()),
                ifs=[
                    Compare(
                        left=Name(id='n', ctx=Load()),
                        ops=[
                            Gt()],
                        comparators=[
                            Constant(value=5)]),
                    Compare(
                        left=Name(id='n', ctx=Load()),
                        ops=[
                            Lt()],
                        comparators=[
                            Constant(value=10)])],
                is_async=0)]))

>>> print(ast.dump(ast.parse('[i async for i in soc]', mode='eval'),
...                indent=4)) # Async comprehension
Expression(
    body=ListComp(
        elt=Name(id='i', ctx=Load()),
        generators=[
            comprehension(
                target=Name(id='i', ctx=Store()),
                iter=Name(id='soc', ctx=Load()),
                is_async=1)]))

문장

class ast.Assign(targets, value, type_comment)

대입. targets는 노드의 리스트이고, value는 단일 노드입니다.

targets의 여러 노드는 각각 같은 값을 할당하는 것을 나타냅니다. 언 패킹은 targets 내에 Tuple이나 List를 넣어 표현됩니다.

type_comment

type_comment는 형 어노테이션이 주석으로 포함된 선택적 문자열입니다.

>>> print(ast.dump(ast.parse('a = b = 1'), indent=4)) # Multiple assignment
Module(
    body=[
        Assign(
            targets=[
                Name(id='a', ctx=Store()),
                Name(id='b', ctx=Store())],
            value=Constant(value=1))])

>>> print(ast.dump(ast.parse('a,b = c'), indent=4)) # Unpacking
Module(
    body=[
        Assign(
            targets=[
                Tuple(
                    elts=[
                        Name(id='a', ctx=Store()),
                        Name(id='b', ctx=Store())],
                    ctx=Store())],
            value=Name(id='c', ctx=Load()))])

class ast.AnnAssign(target, annotation, value, simple)

An assignment with a type annotation. target is a single node and can be a Name, an Attribute or a Subscript. annotation is the annotation, such as a Constant or Name node. value is a single optional node.

simple is always either 0 (indicating a “complex” target) or 1 (indicating a “simple” target). A “simple” target consists solely of a Name node that does not appear between parentheses; all other targets are considered complex. Only simple targets appear in the __annotations__ dictionary of modules and classes.

>>> print(ast.dump(ast.parse('c: int'), indent=4))
Module(
    body=[
        AnnAssign(
            target=Name(id='c', ctx=Store()),
            annotation=Name(id='int', ctx=Load()),
            simple=1)])

>>> print(ast.dump(ast.parse('(a): int = 1'), indent=4)) # Annotation with parenthesis
Module(
    body=[
        AnnAssign(
            target=Name(id='a', ctx=Store()),
            annotation=Name(id='int', ctx=Load()),
            value=Constant(value=1),
            simple=0)])

>>> print(ast.dump(ast.parse('a.b: int'), indent=4)) # Attribute annotation
Module(
    body=[
        AnnAssign(
            target=Attribute(
                value=Name(id='a', ctx=Load()),
                attr='b',
                ctx=Store()),
            annotation=Name(id='int', ctx=Load()),
            simple=0)])

>>> print(ast.dump(ast.parse('a[1]: int'), indent=4)) # Subscript annotation
Module(
    body=[
        AnnAssign(
            target=Subscript(
                value=Name(id='a', ctx=Load()),
                slice=Constant(value=1),
                ctx=Store()),
            annotation=Name(id='int', ctx=Load()),
            simple=0)])

class ast.AugAssign(target, op, value)

증분 대입, 가령 a += 1. 다음 예에서, target은 x(Store 컨텍스트로)를 위한 Name 노드이고, op는 Add이며, value는 값이 1인 Constant입니다.

The target attribute cannot be of class Tuple or List, unlike the targets of Assign.

>>> print(ast.dump(ast.parse('x += 2'), indent=4))
Module(
    body=[
        AugAssign(
            target=Name(id='x', ctx=Store()),
            op=Add(),
            value=Constant(value=2))])

class ast.Raise(exc, cause)

raise 문. exc는 발생시킬 예외 객체로 일반적으로 Call이나 Name이거나, 독립 raise의 경우 None입니다. cause는 raise x from y에서 y에 해당하는 선택적 부분입니다.

>>> print(ast.dump(ast.parse('raise x from y'), indent=4))
Module(
    body=[
        Raise(
            exc=Name(id='x', ctx=Load()),
            cause=Name(id='y', ctx=Load()))])

class ast.Assert(test, msg)

어서션. test는 (Compare 노드와 같은) 조건을 보유합니다. msg는 실패 메시지를 보유합니다.

>>> print(ast.dump(ast.parse('assert x,y'), indent=4))
Module(
    body=[
        Assert(
            test=Name(id='x', ctx=Load()),
            msg=Name(id='y', ctx=Load()))])

class ast.Delete(targets)

del 문을 나타냅니다. targets는 Name, Attribute 또는 Subscript 같은 노드들의 리스트입니다.

>>> print(ast.dump(ast.parse('del x,y,z'), indent=4))
Module(
    body=[
        Delete(
            targets=[
                Name(id='x', ctx=Del()),
                Name(id='y', ctx=Del()),
                Name(id='z', ctx=Del())])])

class ast.Pass

pass 문.

>>> print(ast.dump(ast.parse('pass'), indent=4))
Module(
    body=[
        Pass()])

class ast.TypeAlias(name, type_params, value)

A type alias created through the type statement. name is the name of the alias, type_params is a list of type parameters, and value is the value of the type alias.

>>> print(ast.dump(ast.parse('type Alias = int'), indent=4))
Module(
    body=[
        TypeAlias(
            name=Name(id='Alias', ctx=Store()),
            value=Name(id='int', ctx=Load()))])

Added in version 3.12.

함수나 루프 내부에만 적용할 수 있는 다른 문장들은 다른 섹션에 설명되어 있습니다.

임포트

class ast.Import(names)

import 문. names는 alias 노드의 리스트입니다.

>>> print(ast.dump(ast.parse('import x,y,z'), indent=4))
Module(
    body=[
        Import(
            names=[
                alias(name='x'),
                alias(name='y'),
                alias(name='z')])])

class ast.ImportFrom(module, names, level)

from x import y를 나타냅니다. module은 선행 점이 없는 ‘from’ 이름의 원시 문자열이며, from . import foo와 같은 문장의 경우 None입니다. level은 상대 임포트 수준을 보유하는 정수입니다 (0은 절대 임포트를 의미합니다).

>>> print(ast.dump(ast.parse('from y import x,y,z'), indent=4))
Module(
    body=[
        ImportFrom(
            module='y',
            names=[
                alias(name='x'),
                alias(name='y'),
                alias(name='z')],
            level=0)])

class ast.alias(name, asname)

두 매개 변수 모두 이름의 원시 문자열입니다. 정규 이름을 사용하면 asname은 None이 될 수 있습니다.

>>> print(ast.dump(ast.parse('from ..foo.bar import a as b, c'), indent=4))
Module(
    body=[
        ImportFrom(
            module='foo.bar',
            names=[
                alias(name='a', asname='b'),
                alias(name='c')],
            level=2)])

제어 흐름

참고

else와 같은 선택적 절은 존재하지 않으면 빈 목록으로 저장됩니다.

class ast.If(test, body, orelse)

if 문. test는 (Compare 노드와 같은) 단일 노드를 보유합니다. body와 orelse는 각각 노드 리스트를 보유합니다.

elif 절은 AST에서 특별한 표현이 없지만, 앞의 orelse 섹션 안에서 추가 If 노드로 나타납니다.

>>> print(ast.dump(ast.parse("""
... if x:
...    ...
... elif y:
...    ...
... else:
...    ...
... """), indent=4))
Module(
    body=[
        If(
            test=Name(id='x', ctx=Load()),
            body=[
                Expr(
                    value=Constant(value=Ellipsis))],
            orelse=[
                If(
                    test=Name(id='y', ctx=Load()),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))],
                    orelse=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

class ast.For(target, iter, body, orelse, type_comment)

A for loop. target holds the variable(s) the loop assigns to, as a single Name, Tuple, List, Attribute or Subscript node. iter holds the item to be looped over, again as a single node. body and orelse contain lists of nodes to execute. Those in orelse are executed if the loop finishes normally, rather than via a break statement.

type_comment

type_comment는 형 어노테이션이 주석으로 포함된 선택적 문자열입니다.

>>> print(ast.dump(ast.parse("""
... for x in y:
...     ...
... else:
...     ...
... """), indent=4))
Module(
    body=[
        For(
            target=Name(id='x', ctx=Store()),
            iter=Name(id='y', ctx=Load()),
            body=[
                Expr(
                    value=Constant(value=Ellipsis))],
            orelse=[
                Expr(
                    value=Constant(value=Ellipsis))])])

class ast.While(test, body, orelse)

while 루프. test는 (Compare 노드와 같은) 조건을 보유합니다.

>> print(ast.dump(ast.parse("""
... while x:
...    ...
... else:
...    ...
... """), indent=4))
Module(
    body=[
        While(
            test=Name(id='x', ctx=Load()),
            body=[
                Expr(
                    value=Constant(value=Ellipsis))],
            orelse=[
                Expr(
                    value=Constant(value=Ellipsis))])])

class ast.Break

class ast.Continue

break와 continue 문.

>>> print(ast.dump(ast.parse("""\
... for a in b:
...     if a > 5:
...         break
...     else:
...         continue
...
... """), indent=4))
Module(
    body=[
        For(
            target=Name(id='a', ctx=Store()),
            iter=Name(id='b', ctx=Load()),
            body=[
                If(
                    test=Compare(
                        left=Name(id='a', ctx=Load()),
                        ops=[
                            Gt()],
                        comparators=[
                            Constant(value=5)]),
                    body=[
                        Break()],
                    orelse=[
                        Continue()])])])

class ast.Try(body, handlers, orelse, finalbody)

try 블록. ExceptHandler 노드의 리스트인 handlers를 제외한, 모든 어트리뷰트는 실행할 노드의 리스트입니다.

>>> print(ast.dump(ast.parse("""
... try:
...    ...
... except Exception:
...    ...
... except OtherException as e:
...    ...
... else:
...    ...
... finally:
...    ...
... """), indent=4))
Module(
    body=[
        Try(
            body=[
                Expr(
                    value=Constant(value=Ellipsis))],
            handlers=[
                ExceptHandler(
                    type=Name(id='Exception', ctx=Load()),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                ExceptHandler(
                    type=Name(id='OtherException', ctx=Load()),
                    name='e',
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])],
            orelse=[
                Expr(
                    value=Constant(value=Ellipsis))],
            finalbody=[
                Expr(
                    value=Constant(value=Ellipsis))])])

class ast.TryStar(body, handlers, orelse, finalbody)

try blocks which are followed by except* clauses. The attributes are the same as for Try but the ExceptHandler nodes in handlers are interpreted as except* blocks rather then except.

>>> print(ast.dump(ast.parse("""
... try:
...    ...
... except* Exception:
...    ...
... """), indent=4))
Module(
    body=[
        TryStar(
            body=[
                Expr(
                    value=Constant(value=Ellipsis))],
            handlers=[
                ExceptHandler(
                    type=Name(id='Exception', ctx=Load()),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.11.

class ast.ExceptHandler(type, name, body)

단일 except 절. type은 일치할 예외 형이며, 일반적으로 Name 노드(또는 모두 잡는 except: 절의 경우는 None)입니다. name은 예외를 담을 이름을 위한 원시 문자열이거나, 절에 as foo가 없으면 None입니다. body는 노드의 리스트입니다.

>>> print(ast.dump(ast.parse("""\
... try:
...     a + 1
... except TypeError:
...     pass
... """), indent=4))
Module(
    body=[
        Try(
            body=[
                Expr(
                    value=BinOp(
                        left=Name(id='a', ctx=Load()),
                        op=Add(),
                        right=Constant(value=1)))],
            handlers=[
                ExceptHandler(
                    type=Name(id='TypeError', ctx=Load()),
                    body=[
                        Pass()])])])

class ast.With(items, body, type_comment)

with 블록. items는 컨텍스트 관리자를 나타내는 withitem 노드의 리스트이며, body는 컨텍스트 내에서 들여쓰기 된 블록입니다.

type_comment

type_comment는 형 어노테이션이 주석으로 포함된 선택적 문자열입니다.

class ast.withitem(context_expr, optional_vars)

with 블록의 단일 컨텍스트 관리자. context_expr은 컨텍스트 관리자이며, 종종 Call 노드입니다. optional_vars는 as foo 부분의 경우 Name, Tuple 또는 List이거나, 사용하지 않으면 None입니다.

>>> print(ast.dump(ast.parse("""\
... with a as b, c as d:
...    something(b, d)
... """), indent=4))
Module(
    body=[
        With(
            items=[
                withitem(
                    context_expr=Name(id='a', ctx=Load()),
                    optional_vars=Name(id='b', ctx=Store())),
                withitem(
                    context_expr=Name(id='c', ctx=Load()),
                    optional_vars=Name(id='d', ctx=Store()))],
            body=[
                Expr(
                    value=Call(
                        func=Name(id='something', ctx=Load()),
                        args=[
                            Name(id='b', ctx=Load()),
                            Name(id='d', ctx=Load())]))])])

Pattern matching

class ast.Match(subject, cases)

A match statement. subject holds the subject of the match (the object that is being matched against the cases) and cases contains an iterable of match_case nodes with the different cases.

Added in version 3.10.

class ast.match_case(pattern, guard, body)

A single case pattern in a match statement. pattern contains the match pattern that the subject will be matched against. Note that the AST nodes produced for patterns differ from those produced for expressions, even when they share the same syntax.

The guard attribute contains an expression that will be evaluated if the pattern matches the subject.

body contains a list of nodes to execute if the pattern matches and the result of evaluating the guard expression is true.

>>> print(ast.dump(ast.parse("""
... match x:
...     case [x] if x>0:
...         ...
...     case tuple():
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchSequence(
                        patterns=[
                            MatchAs(name='x')]),
                    guard=Compare(
                        left=Name(id='x', ctx=Load()),
                        ops=[
                            Gt()],
                        comparators=[
                            Constant(value=0)]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                match_case(
                    pattern=MatchClass(
                        cls=Name(id='tuple', ctx=Load())),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchValue(value)

A match literal or value pattern that compares by equality. value is an expression node. Permitted value nodes are restricted as described in the match statement documentation. This pattern succeeds if the match subject is equal to the evaluated value.

>>> print(ast.dump(ast.parse("""
... match x:
...     case "Relevant":
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchValue(
                        value=Constant(value='Relevant')),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchSingleton(value)

A match literal pattern that compares by identity. value is the singleton to be compared against: None, True, or False. This pattern succeeds if the match subject is the given constant.

>>> print(ast.dump(ast.parse("""
... match x:
...     case None:
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchSingleton(value=None),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchSequence(patterns)

A match sequence pattern. patterns contains the patterns to be matched against the subject elements if the subject is a sequence. Matches a variable length sequence if one of the subpatterns is a MatchStar node, otherwise matches a fixed length sequence.

>>> print(ast.dump(ast.parse("""
... match x:
...     case [1, 2]:
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchSequence(
                        patterns=[
                            MatchValue(
                                value=Constant(value=1)),
                            MatchValue(
                                value=Constant(value=2))]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchStar(name)

Matches the rest of the sequence in a variable length match sequence pattern. If name is not None, a list containing the remaining sequence elements is bound to that name if the overall sequence pattern is successful.

>>> print(ast.dump(ast.parse("""
... match x:
...     case [1, 2, *rest]:
...         ...
...     case [*_]:
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchSequence(
                        patterns=[
                            MatchValue(
                                value=Constant(value=1)),
                            MatchValue(
                                value=Constant(value=2)),
                            MatchStar(name='rest')]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                match_case(
                    pattern=MatchSequence(
                        patterns=[
                            MatchStar()]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchMapping(keys, patterns, rest)

A match mapping pattern. keys is a sequence of expression nodes. patterns is a corresponding sequence of pattern nodes. rest is an optional name that can be specified to capture the remaining mapping elements. Permitted key expressions are restricted as described in the match statement documentation.

This pattern succeeds if the subject is a mapping, all evaluated key expressions are present in the mapping, and the value corresponding to each key matches the corresponding subpattern. If rest is not None, a dict containing the remaining mapping elements is bound to that name if the overall mapping pattern is successful.

>>> print(ast.dump(ast.parse("""
... match x:
...     case {1: _, 2: _}:
...         ...
...     case {**rest}:
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchMapping(
                        keys=[
                            Constant(value=1),
                            Constant(value=2)],
                        patterns=[
                            MatchAs(),
                            MatchAs()]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                match_case(
                    pattern=MatchMapping(rest='rest'),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchClass(cls, patterns, kwd_attrs, kwd_patterns)

A match class pattern. cls is an expression giving the nominal class to be matched. patterns is a sequence of pattern nodes to be matched against the class defined sequence of pattern matching attributes. kwd_attrs is a sequence of additional attributes to be matched (specified as keyword arguments in the class pattern), kwd_patterns are the corresponding patterns (specified as keyword values in the class pattern).

This pattern succeeds if the subject is an instance of the nominated class, all positional patterns match the corresponding class-defined attributes, and any specified keyword attributes match their corresponding pattern.

Note: classes may define a property that returns self in order to match a pattern node against the instance being matched. Several builtin types are also matched that way, as described in the match statement documentation.

>>> print(ast.dump(ast.parse("""
... match x:
...     case Point2D(0, 0):
...         ...
...     case Point3D(x=0, y=0, z=0):
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchClass(
                        cls=Name(id='Point2D', ctx=Load()),
                        patterns=[
                            MatchValue(
                                value=Constant(value=0)),
                            MatchValue(
                                value=Constant(value=0))]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                match_case(
                    pattern=MatchClass(
                        cls=Name(id='Point3D', ctx=Load()),
                        kwd_attrs=[
                            'x',
                            'y',
                            'z'],
                        kwd_patterns=[
                            MatchValue(
                                value=Constant(value=0)),
                            MatchValue(
                                value=Constant(value=0)),
                            MatchValue(
                                value=Constant(value=0))]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchAs(pattern, name)

A match “as-pattern”, capture pattern or wildcard pattern. pattern contains the match pattern that the subject will be matched against. If the pattern is None, the node represents a capture pattern (i.e a bare name) and will always succeed.

The name attribute contains the name that will be bound if the pattern is successful. If name is None, pattern must also be None and the node represents the wildcard pattern.

>>> print(ast.dump(ast.parse("""
... match x:
...     case [x] as y:
...         ...
...     case _:
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchAs(
                        pattern=MatchSequence(
                            patterns=[
                                MatchAs(name='x')]),
                        name='y'),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))]),
                match_case(
                    pattern=MatchAs(),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

class ast.MatchOr(patterns)

A match “or-pattern”. An or-pattern matches each of its subpatterns in turn to the subject, until one succeeds. The or-pattern is then deemed to succeed. If none of the subpatterns succeed the or-pattern fails. The patterns attribute contains a list of match pattern nodes that will be matched against the subject.

>>> print(ast.dump(ast.parse("""
... match x:
...     case [x] | (y):
...         ...
... """), indent=4))
Module(
    body=[
        Match(
            subject=Name(id='x', ctx=Load()),
            cases=[
                match_case(
                    pattern=MatchOr(
                        patterns=[
                            MatchSequence(
                                patterns=[
                                    MatchAs(name='x')]),
                            MatchAs(name='y')]),
                    body=[
                        Expr(
                            value=Constant(value=Ellipsis))])])])

Added in version 3.10.

Type parameters

Type parameters can exist on classes, functions, and type aliases.

class ast.TypeVar(name, bound, default_value)

A typing.TypeVar. name is the name of the type variable. bound is the bound or constraints, if any. If bound is a Tuple, it represents constraints; otherwise it represents the bound. default_value is the default value; if the TypeVar has no default, this attribute will be set to None.

>>> print(ast.dump(ast.parse("type Alias[T: int = bool] = list[T]"), indent=4))
Module(
    body=[
        TypeAlias(
            name=Name(id='Alias', ctx=Store()),
            type_params=[
                TypeVar(
                    name='T',
                    bound=Name(id='int', ctx=Load()),
                    default_value=Name(id='bool', ctx=Load()))],
            value=Subscript(
                value=Name(id='list', ctx=Load()),
                slice=Name(id='T', ctx=Load()),
                ctx=Load()))])

Added in version 3.12.

버전 3.13에서 변경: Added the default_value parameter.

class ast.ParamSpec(name, default_value)

A typing.ParamSpec. name is the name of the parameter specification. default_value is the default value; if the ParamSpec has no default, this attribute will be set to None.

>>> print(ast.dump(ast.parse("type Alias[**P = (int, str)] = Callable[P, int]"), indent=4))
Module(
    body=[
        TypeAlias(
            name=Name(id='Alias', ctx=Store()),
            type_params=[
                ParamSpec(
                    name='P',
                    default_value=Tuple(
                        elts=[
                            Name(id='int', ctx=Load()),
                            Name(id='str', ctx=Load())],
                        ctx=Load()))],
            value=Subscript(
                value=Name(id='Callable', ctx=Load()),
                slice=Tuple(
                    elts=[
                        Name(id='P', ctx=Load()),
                        Name(id='int', ctx=Load())],
                    ctx=Load()),
                ctx=Load()))])

Added in version 3.12.

버전 3.13에서 변경: Added the default_value parameter.

class ast.TypeVarTuple(name, default_value)

A typing.TypeVarTuple. name is the name of the type variable tuple. default_value is the default value; if the TypeVarTuple has no default, this attribute will be set to None.

>>> print(ast.dump(ast.parse("type Alias[*Ts = ()] = tuple[*Ts]"), indent=4))
Module(
    body=[
        TypeAlias(
            name=Name(id='Alias', ctx=Store()),
            type_params=[
                TypeVarTuple(
                    name='Ts',
                    default_value=Tuple(ctx=Load()))],
            value=Subscript(
                value=Name(id='tuple', ctx=Load()),
                slice=Tuple(
                    elts=[
                        Starred(
                            value=Name(id='Ts', ctx=Load()),
                            ctx=Load())],
                    ctx=Load()),
                ctx=Load()))])

Added in version 3.12.

버전 3.13에서 변경: Added the default_value parameter.

함수와 클래스 정의

class ast.FunctionDef(name, args, body, decorator_list, returns, type_comment, type_params)

함수 정의.

name은 함수 이름의 원시 문자열입니다.

args is an arguments node.

body는 함수 내부의 노드 리스트입니다.

decorator_list는 적용할 데코레이터 리스트이며, 가장 바깥쪽에 먼저 저장됩니다 (즉, 리스트의 첫 번째가 마지막에 적용됩니다).

returns는 반환 어노테이션입니다.

type_params is a list of type parameters.

type_comment

type_comment는 형 어노테이션이 주석으로 포함된 선택적 문자열입니다.

버전 3.12에서 변경: Added type_params.

class ast.Lambda(args, body)

lambda는 표현식 내에서 사용할 수 있는 최소 함수 정의입니다. FunctionDef와 달리, body는 단일 노드를 보유합니다.

>>> print(ast.dump(ast.parse('lambda x,y: ...'), indent=4))
Module(
    body=[
        Expr(
            value=Lambda(
                args=arguments(
                    args=[
                        arg(arg='x'),
                        arg(arg='y')]),
                body=Constant(value=Ellipsis)))])

class ast.arguments(posonlyargs, args, vararg, kwonlyargs, kw_defaults, kwarg, defaults)

함수의 인자.

posonlyargs, args 및 kwonlyargs는 arg 노드의 리스트입니다.

vararg와 kwarg는 *args, **kwargs 매개 변수를 참조하는 단일 arg 노드입니다.

kw_defaults는 키워드 전용 인자의 기본값 리스트입니다. 어떤 것이 None이면, 해당 인자는 필수입니다.

defaults는 위치적으로 전달될 수 있는 인자의 기본값 리스트입니다. 기본값 수가 더 적으면, 마지막 n개의 인자에 해당합니다.

class ast.arg(arg, annotation, type_comment)

A single argument in a list. arg is a raw string of the argument name; annotation is its annotation, such as a Name node.

type_comment

type_comment는 주석으로 제공된 형 어노테이션이 있는 선택적 문자열입니다.

>>> print(ast.dump(ast.parse("""\
... @decorator1
... @decorator2
... def f(a: 'annotation', b=1, c=2, *d, e, f=3, **g) -> 'return annotation':
...     pass
... """), indent=4))
Module(
    body=[
        FunctionDef(
            name='f',
            args=arguments(
                args=[
                    arg(
                        arg='a',
                        annotation=Constant(value='annotation')),
                    arg(arg='b'),
                    arg(arg='c')],
                vararg=arg(arg='d'),
                kwonlyargs=[
                    arg(arg='e'),
                    arg(arg='f')],
                kw_defaults=[
                    None,
                    Constant(value=3)],
                kwarg=arg(arg='g'),
                defaults=[
                    Constant(value=1),
                    Constant(value=2)]),
            body=[
                Pass()],
            decorator_list=[
                Name(id='decorator1', ctx=Load()),
                Name(id='decorator2', ctx=Load())],
            returns=Constant(value='return annotation'))])

class ast.Return(value)

return 문.

>>> print(ast.dump(ast.parse('return 4'), indent=4))
Module(
    body=[
        Return(
            value=Constant(value=4))])

class ast.Yield(value)

class ast.YieldFrom(value)

A yield or yield from expression. Because these are expressions, they must be wrapped in an Expr node if the value sent back is not used.

>>> print(ast.dump(ast.parse('yield x'), indent=4))
Module(
    body=[
        Expr(
            value=Yield(
                value=Name(id='x', ctx=Load())))])

>>> print(ast.dump(ast.parse('yield from x'), indent=4))
Module(
    body=[
        Expr(
            value=YieldFrom(
                value=Name(id='x', ctx=Load())))])

class ast.Global(names)

class ast.Nonlocal(names)

global과 nonlocal 문. names는 원시 문자열 리스트입니다.

>>> print(ast.dump(ast.parse('global x,y,z'), indent=4))
Module(
    body=[
        Global(
            names=[
                'x',
                'y',
                'z'])])

>>> print(ast.dump(ast.parse('nonlocal x,y,z'), indent=4))
Module(
    body=[
        Nonlocal(
            names=[
                'x',
                'y',
                'z'])])

class ast.ClassDef(name, bases, keywords, body, decorator_list, type_params)

클래스 정의.

name은 클래스 이름의 원시 문자열입니다.

bases는 명시적으로 지정된 베이스 클래스의 노드 리스트입니다.

keywords is a list of keyword nodes, principally for ‘metaclass’. Other keywords will be passed to the metaclass, as per PEP 3115 [https://peps.python.org/pep-3115/].

body는 클래스 정의 내에서 코드를 나타내는 노드 리스트입니다.

decorator_list는 FunctionDef에서와 같이 노드 리스트입니다.

type_params is a list of type parameters.

>>> print(ast.dump(ast.parse("""\
... @decorator1
... @decorator2
... class Foo(base1, base2, metaclass=meta):
...     pass
... """), indent=4))
Module(
    body=[
        ClassDef(
            name='Foo',
            bases=[
                Name(id='base1', ctx=Load()),
                Name(id='base2', ctx=Load())],
            keywords=[
                keyword(
                    arg='metaclass',
                    value=Name(id='meta', ctx=Load()))],
            body=[
                Pass()],
            decorator_list=[
                Name(id='decorator1', ctx=Load()),
                Name(id='decorator2', ctx=Load())])])

버전 3.12에서 변경: Added type_params.

Async와 await

class ast.AsyncFunctionDef(name, args, body, decorator_list, returns, type_comment, type_params)

async def 함수 정의. FunctionDef와 같은 필드를 갖습니다.

버전 3.12에서 변경: Added type_params.

class ast.Await(value)

await 표현식. value는 기다릴 대상입니다. AsyncFunctionDef의 본문에서만 유효합니다.

>>> print(ast.dump(ast.parse("""\
... async def f():
...     await other_func()
... """), indent=4))
Module(
    body=[
        AsyncFunctionDef(
            name='f',
            args=arguments(),
            body=[
                Expr(
                    value=Await(
                        value=Call(
                            func=Name(id='other_func', ctx=Load()))))])])

class ast.AsyncFor(target, iter, body, orelse, type_comment)

class ast.AsyncWith(items, body, type_comment)

async for 루프와 async with 컨텍스트 관리자. 이들은 각각 For와 With와 같은 필드를 갖습니다. AsyncFunctionDef의 본문에서만 유효합니다.

참고

문자열이 ast.parse()로 구문 분석될 때, 반환된 트리의 연산자 노드(ast.operator, ast.unaryop, ast.cmpop, ast.boolop 및 ast.expr_context의 서브 클래스)는 싱글톤이 됩니다. 어느 하나의 변경 사항은 같은 값으로 등장하는 다른 모든 곳에 반영됩니다 (예를 들어 ast.Add).

ast 도우미

노드 클래스 외에도, ast 모듈은 추상 구문 트리를 탐색하기 위해 다음 유틸리티 함수와 클래스를 정의합니다:

ast.parse(source, filename='<unknown>', mode='exec', *, type_comments=False, feature_version=None, optimize=-1)

Parse the source into an AST node. Equivalent to compile(source, filename, mode, flags=FLAGS_VALUE, optimize=optimize), where FLAGS_VALUE is ast.PyCF_ONLY_AST if optimize <= 0 and ast.PyCF_OPTIMIZED_AST otherwise.

If type_comments=True is given, the parser is modified to check and return type comments as specified by PEP 484 [https://peps.python.org/pep-0484/] and PEP 526 [https://peps.python.org/pep-0526/]. This is equivalent to adding ast.PyCF_TYPE_COMMENTS to the flags passed to compile(). This will report syntax errors for misplaced type comments. Without this flag, type comments will be ignored, and the type_comment field on selected AST nodes will always be None. In addition, the locations of # type: ignore comments will be returned as the type_ignores attribute of Module (otherwise it is always an empty list).

또한, mode가 'func_type'이면, 입력 문법은 PEP 484 [https://peps.python.org/pep-0484/] “서명 형 주석”에 따라 수정됩니다, 예를 들어 (str, int) -> List[str].

Setting feature_version to a tuple (major, minor) will result in a “best-effort” attempt to parse using that Python version’s grammar. For example, setting feature_version=(3, 9) will attempt to disallow parsing of match statements. Currently major must equal to 3. The lowest supported version is (3, 7) (and this may increase in future Python versions); the highest is sys.version_info[0:2]. “Best-effort” attempt means there is no guarantee that the parse (or success of the parse) is the same as when run on the Python version corresponding to feature_version.

If source contains a null character (\0), ValueError is raised.

경고

Note that successfully parsing source code into an AST object doesn’t guarantee that the source code provided is valid Python code that can be executed as the compilation step can raise further SyntaxError exceptions. For instance, the source return 42 generates a valid AST node for a return statement, but it cannot be compiled alone (it needs to be inside a function node).

In particular, ast.parse() won’t do any scoping checks, which the compilation step does.

경고

파이썬 AST 컴파일러의 스택 깊이 제한으로 인해 충분히 크고/복잡한 문자열로 파이썬 인터프리터가 충돌하도록 만들 수 있습니다.

버전 3.8에서 변경: type_comments, mode='func_type' 및 feature_version추가했습니다.

버전 3.13에서 변경: The minimum supported version for feature_version is now (3, 7). The optimize argument was added.

ast.unparse(ast_obj)

ast.AST 객체를 역 구문 분석하고 ast.parse()로 다시 구문 분석할 경우 동등한 ast.AST 객체를 생성하는 코드가 포함된 문자열을 생성합니다.

경고

생성된 코드 문자열은 ast.AST 객체를 생성한 원래 코드와 반드시 같을 필요는 없습니다 (상수 튜플/frozenset과 같은 컴파일러 최적화 없이).

경고

매우 복잡한 표현식을 역 구분 분석하려고 하면 RecursionError가 발생할 수 있습니다.

Added in version 3.9.

ast.literal_eval(node_or_string)

Evaluate an expression node or a string containing only a Python literal or container display. The string or node provided may only consist of the following Python literal structures: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, None and Ellipsis.

This can be used for evaluating strings containing Python values without the need to parse the values oneself. It is not capable of evaluating arbitrarily complex expressions, for example involving operators or indexing.

This function had been documented as “safe” in the past without defining what that meant. That was misleading. This is specifically designed not to execute Python code, unlike the more general eval(). There is no namespace, no name lookups, or ability to call out. But it is not free from attack: A relatively small input can lead to memory exhaustion or to C stack exhaustion, crashing the process. There is also the possibility for excessive CPU consumption denial of service on some inputs. Calling it on untrusted data is thus not recommended.

경고

It is possible to crash the Python interpreter due to stack depth limitations in Python’s AST compiler.

It can raise ValueError, TypeError, SyntaxError, MemoryError and RecursionError depending on the malformed input.

버전 3.2에서 변경: 이제 바이트열과 집합 리터럴을 허용합니다.

버전 3.9에서 변경: 이제 'set()'으로 빈 집합을 만드는 것을 지원합니다.

버전 3.10에서 변경: For string inputs, leading spaces and tabs are now stripped.

ast.get_docstring(node, clean=True)

주어진 node(FunctionDef, AsyncFunctionDef, ClassDef 또는 Module 노드이어야 합니다)의 독스트링이나, 독스트링이 없으면 None을 반환합니다. clean이 참이면, inspect.cleandoc()으로 독스트링의 들여쓰기를 정리합니다.

버전 3.5에서 변경: AsyncFunctionDef 가 이제 지원됩니다.

ast.get_source_segment(source, node, *, padded=False)

Get source code segment of the source that generated node. If some location information (lineno, end_lineno, col_offset, or end_col_offset) is missing, return None.

padded가 True이면, 여러 줄 문장의 첫 번째 줄은 원래 위치와 일치하도록 스페이스로 채워집니다.

Added in version 3.8.

ast.fix_missing_locations(node)

When you compile a node tree with compile(), the compiler expects lineno and col_offset attributes for every node that supports them. This is rather tedious to fill in for generated nodes, so this helper adds these attributes recursively where not already set, by setting them to the values of the parent node. It works recursively starting at node.

ast.increment_lineno(node, n=1)

node에서 시작하는 트리에서 각 노드의 줄 번호와 끝 줄 번호를 n만큼 증가시킵니다. 파일의 다른 위치로 “코드를 이동”하는 데 유용합니다.

ast.copy_location(new_node, old_node)

Copy source location (lineno, col_offset, end_lineno, and end_col_offset) from old_node to new_node if possible, and return new_node.

ast.iter_fields(node)

node에 존재하는 node._fields의 각 필드에 대해 (fieldname, value) 튜플을 산출합니다.

ast.iter_child_nodes(node)

node의 모든 직접 자식 노드, 즉 노드인 모든 필드와 노드 리스트인 필드의 모든 항목을 산출합니다.

ast.walk(node)

node로 시작하는 트리(node 자체를 포함합니다)의 모든 자손 노드를 지정된 순서 없이 재귀적으로 산출합니다. 이는 노드를 제자리에서 수정하고 문맥을 신경 쓰지 않을 때 유용합니다.

class ast.NodeVisitor

추상 구문 트리를 걷고 발견된 모든 노드에 대해 방문자 함수를 호출하는 노드 방문자 베이스 클래스. 이 함수는 visit() 메서드에 의해 전달되는 값을 반환할 수 있습니다.

이 클래스는 서브 클래싱하고자 하는 것이며, 서브 클래스는 방문자 메서드를 추가합니다.

visit(node)

노드를 방문합니다. 기본 구현은 self.visit_classname이라는 메서드를 호출하는데, 여기서 classname 은 노드 클래스의 이름입니다. 또는 이 메서드가 없으면 generic_visit()를 호출합니다.

generic_visit(node)

이 방문자는 노드의 자식에 대해 visit()를 호출합니다.

방문자가 generic_visit()를 호출하거나 직접 방문하지 않는 한, 사용자 정의 방문자 메서드가 있는 노드의 자식 노드는 방문 되지 않음에 유의하십시오.

visit_Constant(node)

Handles all constant nodes.

탐색 중에 노드에 변경 사항을 적용하려면 NodeVisitor를 사용하지 마십시오. 이를 위해 수정을 허락하는 특수한 방문자(NodeTransformer)가 있습니다.

버전 3.8부터 폐지됨: Methods visit_Num(), visit_Str(), visit_Bytes(), visit_NameConstant() and visit_Ellipsis() are deprecated now and will not be called in future Python versions. Add the visit_Constant() method to handle all constant nodes.

class ast.NodeTransformer

추상 구문 트리를 걷고 노드 수정을 허락하는 NodeVisitor 서브 클래스.

NodeTransformer는 AST를 걷고 방문자 메서드의 반환 값을 사용하여 이전 노드를 바꾸거나 제거합니다. 방문자 메서드의 반환 값이 None이면, 노드가 그 위치에서 제거되고, 그렇지 않으면 반환 값으로 치환됩니다. 반환 값은 원래 노드일 수 있으며, 이때는 치환이 일어나지 않습니다.

다음은 모든 이름 조회(foo)를 data['foo']로 다시 쓰는 변환기 예제입니다:

class RewriteName(NodeTransformer):

    def visit_Name(self, node):
        return Subscript(
            value=Name(id='data', ctx=Load()),
            slice=Constant(value=node.id),
            ctx=node.ctx
        )

Keep in mind that if the node you’re operating on has child nodes you must either transform the child nodes yourself or call the generic_visit() method for the node first.

문장의 컬렉션의 일부인 노드의 경우 (모든 문장 노드에 적용됩니다), 방문자는 단일 노드가 아닌 노드 리스트를 반환 할 수도 있습니다.

If NodeTransformer introduces new nodes (that weren’t part of original tree) without giving them location information (such as lineno), fix_missing_locations() should be called with the new sub-tree to recalculate the location information:

tree = ast.parse('foo', mode='eval')
new_tree = fix_missing_locations(RewriteName().visit(tree))

일반적으로 다음과 같이 변환기를 사용합니다:

node = YourTransformer().visit(node)

ast.dump(node, annotate_fields=True, include_attributes=False, *, indent=None, show_empty=False)

node에서 포맷된 트리 덤프를 반환합니다. 이것은 주로 디버깅 목적으로 유용합니다. annotate_fields가 참이면 (기본값), 반환된 문자열에 필드의 이름과 값이 표시됩니다. annotate_fields가 거짓이면, 모호하지 않은 필드 이름을 생략하여 결과 문자열이 더 간결해집니다. 줄 번호와 열 오프셋과 같은 어트리뷰트는 기본적으로 덤프 되지 않습니다. 원한다면, include_attributes를 참으로 설정할 수 있습니다.

indent가 음이 아닌 정수나 문자열이면, 트리는 그 들여쓰기 수준으로 예쁘게 인쇄됩니다. 들여쓰기 수준 0, 음수 또는 ""는 줄 넘김 만 삽입합니다. None(기본값)은 단일 줄 표현을 선택합니다. 양의 정수 indent를 사용하면 수준마다 그만큼 들여쓰기 됩니다. indent가 문자열(가령 "\t")이면, 해당 문자열은 각 수준을 들여 쓰는 데 사용됩니다.

If show_empty is False (the default), empty lists and fields that are None will be omitted from the output.

버전 3.9에서 변경: indent 옵션을 추가했습니다.

버전 3.13에서 변경: Added the show_empty option.

>>> print(ast.dump(ast.parse("""\
... async def f():
...     await other_func()
... """), indent=4, show_empty=True))
Module(
    body=[
        AsyncFunctionDef(
            name='f',
            args=arguments(
                posonlyargs=[],
                args=[],
                kwonlyargs=[],
                kw_defaults=[],
                defaults=[]),
            body=[
                Expr(
                    value=Await(
                        value=Call(
                            func=Name(id='other_func', ctx=Load()),
                            args=[],
                            keywords=[])))],
            decorator_list=[],
            type_params=[])],
    type_ignores=[])

컴파일러 플래그

프로그램 컴파일에 대한 효과를 변경하기 위해 다음 플래그를 compile()에 전달할 수 있습니다:

ast.PyCF_ALLOW_TOP_LEVEL_AWAIT

최상위 수준 await, async for, async with 및 비동기 컴프리헨션에 대한 지원을 활성화합니다.

Added in version 3.8.

ast.PyCF_ONLY_AST

컴파일된 코드 객체를 반환하는 대신 추상 구문 트리를 생성하고 반환합니다.

ast.PyCF_OPTIMIZED_AST

The returned AST is optimized according to the optimize argument in compile() or ast.parse().

Added in version 3.13.

ast.PyCF_TYPE_COMMENTS

PEP 484 [https://peps.python.org/pep-0484/]와 PEP 526 [https://peps.python.org/pep-0526/] 스타일 형 주석(# type: <type>, # type: ignore <stuff>)에 대한 지원을 활성화합니다.

Added in version 3.8.

ast.compare(a, b, /, *, compare_attributes=False)

Recursively compares two ASTs.

compare_attributes affects whether AST attributes are considered in the comparison. If compare_attributes is False (default), then attributes are ignored. Otherwise they must all be equal. This option is useful to check whether the ASTs are structurally equal but differ in whitespace or similar details. Attributes include line numbers and column offsets.

Added in version 3.14.

명령 줄 사용법

Added in version 3.9.

ast 모듈은 명령 줄에서 스크립트로 실행될 수 있습니다. 다음과 같이 간단합니다:

python -m ast [-m <mode>] [-a] [infile]

다음과 같은 옵션이 허용됩니다:

-h, --help

도움말 메시지를 표시하고 종료합니다.

-m <mode>

--mode <mode>

parse()의 mode 인자와 같이, 컴파일해야 하는 코드 종류를 지정합니다.

--no-type-comments

형 주석을 구문 분석하지 않습니다.

-a, --include-attributes

줄 번호와 열 오프셋과 같은 어트리뷰트를 포함합니다.

-i <indent>

--indent <indent>

AST에서 노드 들여쓰기(스페이스 수).

infile이 지정되면 그 내용이 AST로 구문 분석되고 stdout에 덤프 됩니다. 그렇지 않으면, stdin에서 내용을 읽습니다.

더 보기

Green Tree Snakes [https://greentreesnakes.readthedocs.io/], 파이썬 AST로 작업하는 것에 대한 자세한 내용이 있는 외부 문서 자원.

ASTTokens [https://asttokens.readthedocs.io/en/latest/user-guide.html]는 토큰의 위치와 토큰을 생성한 소스 코드의 텍스트로 파이썬 AST에 주석을 추가합니다. 이는 소스 코드 변환을 수행하는 도구에 유용합니다.

leoAst.py [https://leo-editor.github.io/leo-editor/appendices.html#leoast-py] unifies the token-based and parse-tree-based views of python programs by inserting two-way links between tokens and ast nodes.

LibCST [https://libcst.readthedocs.io/]는 코드를 ast 트리처럼 보이고 모든 포매팅 세부 정보를 유지하는 구상 구문 트리(Concrete Syntax Tree)로 구문 분석합니다. 자동화된 리팩토링 (codemod) 응용 프로그램과 린터(linter)를 구축하는 데 유용합니다.

Parso [https://parso.readthedocs.io] is a Python parser that supports error recovery and round-trip parsing for different Python versions (in multiple Python versions). Parso is also able to list multiple syntax errors in your Python file.

symtable — Access to the compiler’s symbol tables

소스 코드: Lib/symtable.py [https://github.com/python/cpython/tree/main/Lib/symtable.py]

심볼 테이블은 바이트 코드가 생성되기 바로 전에 AST에서 컴파일러에 의해 생성됩니다. 심볼 테이블은 코드에서 모든 식별자의 스코프를 계산합니다. symtable은 이러한 테이블을 검사하는 인터페이스를 제공합니다.

심볼 테이블 생성하기

symtable.symtable(code, filename, compile_type)

파이썬 소스 code에 대한 최상위 SymbolTable을 반환합니다. filename은 코드가 들어있는 파일의 이름입니다. compile_type은 compile()에 대한 mode 인자와 같습니다.

심볼 테이블 검사하기

class symtable.SymbolTableType

An enumeration indicating the type of a SymbolTable object.

MODULE = "module"

Used for the symbol table of a module.

FUNCTION = "function"

Used for the symbol table of a function.

CLASS = "class"

Used for the symbol table of a class.

The following members refer to different flavors of annotation scopes.

ANNOTATION = "annotation"

Used for annotations if from __future__ import annotations is active.

TYPE_ALIAS = "type alias"

Used for the symbol table of type constructions.

TYPE_PARAMETERS = "type parameters"

Used for the symbol table of generic functions or generic classes.

TYPE_VARIABLE = "type variable"

Used for the symbol table of the bound, the constraint tuple or the default value of a single type variable in the formal sense, i.e., a TypeVar, a TypeVarTuple or a ParamSpec object (the latter two do not support a bound or a constraint tuple).

Added in version 3.13.

class symtable.SymbolTable

블록에 대한 이름 공간 테이블. 생성자는 공개되지 않습니다.

get_type()

Return the type of the symbol table. Possible values are members of the SymbolTableType enumeration.

버전 3.12에서 변경: Added 'annotation', 'TypeVar bound', 'type alias', and 'type parameter' as possible return values.

버전 3.13에서 변경: Return values are members of the SymbolTableType enumeration.

The exact values of the returned string may change in the future, and thus, it is recommended to use SymbolTableType members instead of hard-coded strings.

get_id()

테이블의 식별자를 돌려줍니다.

get_name()

Return the table’s name. This is the name of the class if the table is for a class, the name of the function if the table is for a function, or 'top' if the table is global (get_type() returns 'module'). For type parameter scopes (which are used for generic classes, functions, and type aliases), it is the name of the underlying class, function, or type alias. For type alias scopes, it is the name of the type alias. For TypeVar bound scopes, it is the name of the TypeVar.

get_lineno()

이 테이블이 나타내는 블록의 첫 번째 줄 번호를 반환합니다.

is_optimized()

이 테이블의 지역(locals)을 최적화할 수 있으면 True를 반환합니다.

is_nested()

블록이 중첩된 클래스나 함수면 True를 반환합니다.

has_children()

블록에 중첩된 이름 공간이 있으면 True를 반환합니다. 이것들은 get_children()으로 얻을 수 있습니다.

get_identifiers()

Return a view object containing the names of symbols in the table. See the documentation of view objects.

lookup(name)

테이블에서 name을 찾아서 Symbol 인스턴스를 반환합니다.

get_symbols()

테이블에 있는 이름에 대한 Symbol 인스턴스 리스트를 반환합니다.

get_children()

중첩된 심볼 테이블의 리스트를 반환합니다.

class symtable.Function

A namespace for a function or method. This class inherits from SymbolTable.

get_parameters()

이 함수의 매개 변수 이름을 포함하는 튜플을 반환합니다.

get_locals()

이 함수의 지역 이름을 포함하는 튜플을 반환합니다.

get_globals()

이 함수의 전역 이름을 포함하는 튜플을 반환합니다.

get_nonlocals()

Return a tuple containing names of explicitly declared nonlocals in this function.

get_frees()

Return a tuple containing names of free (closure) variables in this function.

class symtable.Class

A namespace of a class. This class inherits from SymbolTable.

get_methods()

Return a tuple containing the names of method-like functions declared in the class.

Here, the term ‘method’ designates any function defined in the class body via def or async def.

Functions defined in a deeper scope (e.g., in an inner class) are not picked up by get_methods().

For example:

>>> import symtable
>>> st = symtable.symtable('''
... def outer(): pass
...
... class A:
...    def f():
...        def w(): pass
...
...    def g(self): pass
...
...    @classmethod
...    async def h(cls): pass
...
...    global outer
...    def outer(self): pass
... ''', 'test', 'exec')
>>> class_A = st.get_children()[2]
>>> class_A.get_methods()
('f', 'g', 'h')

Although A().f() raises TypeError at runtime, A.f is still considered as a method-like function.

Deprecated since version 3.14, will be removed in version 3.16.

class symtable.Symbol

소스의 식별자에 해당하는 SymbolTable의 항목. 생성자는 공개되지 않습니다.

get_name()

심볼의 이름을 돌려줍니다.

is_referenced()

심볼이 블록에서 사용되면 True를 반환합니다.

is_imported()

심볼이 import 문에서 만들어지면 True를 반환합니다.

is_parameter()

심볼이 매개 변수면 True를 반환합니다.

is_type_parameter()

Return True if the symbol is a type parameter.

Added in version 3.14.

is_global()

심볼이 전역이면 True를 반환합니다.

is_nonlocal()

심볼이 nonlocal이면 True를 반환합니다.

is_declared_global()

심볼이 global 문으로 전역으로 선언되면 True를 반환합니다.

is_local()

심볼이 블록의 지역이면 True를 반환합니다.

is_annotated()

심볼이 어노테이트 되었으면 True를 반환합니다.

Added in version 3.6.

is_free()

심볼이 블록에서 참조되지만 대입되지 않으면 True를 반환합니다.

is_free_class()

Return True if a class-scoped symbol is free from the perspective of a method.

Consider the following example:

def f():
    x = 1  # function-scoped
    class C:
        x = 2  # class-scoped
        def method(self):
            return x

In this example, the class-scoped symbol x is considered to be free from the perspective of C.method, thereby allowing the latter to return 1 at runtime and not 2.

Added in version 3.14.

is_assigned()

심볼이 블록에 대입되면 True를 반환합니다.

is_comp_iter()

Return True if the symbol is a comprehension iteration variable.

Added in version 3.14.

is_comp_cell()

Return True if the symbol is a cell in an inlined comprehension.

Added in version 3.14.

is_namespace()

이름 연결(name binding)이 새로운 이름 공간을 도입하면 True를 반환합니다.

이름이 함수나 클래스 문의 대상으로 사용되면 참입니다.

예를 들면:

>>> table = symtable.symtable("def some_func(): pass", "string", "exec")
>>> table.lookup("some_func").is_namespace()
True

하나의 이름을 여러 객체에 연결할 수 있음에 유의하십시오. 결과가 True 이면, 이름은 새 이름 공간을 도입하지 않는 int 나 list와 같은 다른 객체에도 연결되어있을 수 있습니다.

get_namespaces()

이 이름에 연결된 이름 공간의 리스트를 돌려줍니다.

get_namespace()

Return the namespace bound to this name. If more than one or no namespace is bound to this name, a ValueError is raised.

Command-Line Usage

Added in version 3.13.

The symtable module can be executed as a script from the command line.

python -m symtable [infile...]

Symbol tables are generated for the specified Python source files and dumped to stdout. If no input file is specified, the content is read from stdin.

token — Constants used with Python parse trees

소스 코드: Lib/token.py [https://github.com/python/cpython/tree/main/Lib/token.py]

This module provides constants which represent the numeric values of leaf nodes of the parse tree (terminal tokens). Refer to the file Grammar/Tokens in the Python distribution for the definitions of the names in the context of the language grammar. The specific numeric values which the names map to may change between Python versions.

이 모듈은 숫자 코드에서 이름으로의 매핑과 몇몇 함수도 제공합니다. 이 함수는 파이썬 C 헤더 파일의 정의를 반영합니다.

token.tok_name

이 모듈에 정의된 상수의 숫자 값을 다시 이름 문자열로 매핑하여 사람이 읽을 수 있는 구문 분석 트리 표현을 생성할 수 있도록 하는 딕셔너리.

token.ISTERMINAL(x)

터미널 토큰값이면 True를 반환합니다.

token.ISNONTERMINAL(x)

비 터미널 토큰값이면 True를 반환합니다.

token.ISEOF(x)

x가 입력의 마지막을 나타내는 표시면 True를 반환합니다.

토큰 상수는 다음과 같습니다:

token.ENDMARKER

token.NAME

token.NUMBER

token.STRING

token.NEWLINE

token.INDENT

token.DEDENT

token.LPAR

"("의 토큰값.

token.RPAR

")"의 토큰값.

token.LSQB

"["의 토큰값.

token.RSQB

"]"의 토큰값.

token.COLON

":"의 토큰값.

token.COMMA

","의 토큰값.

token.SEMI

";"의 토큰값.

token.PLUS

"+"의 토큰값.

token.MINUS

"-"의 토큰값.

token.STAR

"*"의 토큰값.

token.SLASH

"/"의 토큰값.

token.VBAR

"|"의 토큰값.

token.AMPER

"&"의 토큰값.

token.LESS

"<"의 토큰값.

token.GREATER

">"의 토큰값.

token.EQUAL

"="의 토큰값.

token.DOT

"."의 토큰값.

token.PERCENT

"%"의 토큰값.

token.LBRACE

"{"의 토큰값.

token.RBRACE

"}"의 토큰값.

token.EQEQUAL

"=="의 토큰값.

token.NOTEQUAL

"!="의 토큰값.

token.LESSEQUAL

"<="의 토큰값.

token.GREATEREQUAL

">="의 토큰값.

token.TILDE

"~"의 토큰값.

token.CIRCUMFLEX

"^"의 토큰값.

token.LEFTSHIFT

"<<"의 토큰값.

token.RIGHTSHIFT

">>"의 토큰값.

token.DOUBLESTAR

"**"의 토큰값.

token.PLUSEQUAL

"+="의 토큰값.

token.MINEQUAL

"-="의 토큰값.

token.STAREQUAL

"*="의 토큰값.

token.SLASHEQUAL

"/="의 토큰값.

token.PERCENTEQUAL

"%="의 토큰값.

token.AMPEREQUAL

"&="의 토큰값.

token.VBAREQUAL

"|="의 토큰값.

token.CIRCUMFLEXEQUAL

"^="의 토큰값.

token.LEFTSHIFTEQUAL

"<<="의 토큰값.

token.RIGHTSHIFTEQUAL

">>="의 토큰값.

token.DOUBLESTAREQUAL

"**="의 토큰값.

token.DOUBLESLASH

"//"의 토큰값.

token.DOUBLESLASHEQUAL

"//="의 토큰값.

token.AT

"@"의 토큰값.

token.ATEQUAL

"@="의 토큰값.

token.RARROW

"->"의 토큰값.

token.ELLIPSIS

"..."의 토큰값.

token.COLONEQUAL

":="의 토큰값.

token.EXCLAMATION

Token value for "!".

token.OP

token.TYPE_IGNORE

token.TYPE_COMMENT

token.SOFT_KEYWORD

token.FSTRING_START

token.FSTRING_MIDDLE

token.FSTRING_END

token.COMMENT

token.NL

token.ERRORTOKEN

token.N_TOKENS

token.NT_OFFSET

다음 토큰 유형 값은 C 토크나이저가 사용하지 않지만 tokenize 모듈에 필요합니다.

token.COMMENT

주석을 나타내는 데 사용되는 토큰값.

token.NL

비종결 줄넘김을 나타내는데 사용되는 토큰값. NEWLINE 토큰은 파이썬 코드의 논리적 줄의 끝을 나타냅니다; NL 토큰은 코드의 논리적 줄이 여러 물리적 줄로 이어질 때 생성됩니다.

token.ENCODING

소스 바이트열을 텍스트로 디코딩하는 데 사용되는 인코딩을 나타내는 토큰값. tokenize.tokenize()에 의해 반환되는 첫 번째 토큰은 항상 ENCODING 토큰입니다.

token.TYPE_COMMENT

Token value indicating that a type comment was recognized. Such tokens are only produced when ast.parse() is invoked with type_comments=True.

버전 3.5에서 변경: Added AWAIT and ASYNC tokens.

버전 3.7에서 변경: COMMENT, NL 및 ENCODING 토큰이 추가되었습니다.

버전 3.7에서 변경: Removed AWAIT and ASYNC tokens. “async” and “await” are now tokenized as NAME tokens.

버전 3.8에서 변경: Added TYPE_COMMENT, TYPE_IGNORE, COLONEQUAL. Added AWAIT and ASYNC tokens back (they’re needed to support parsing older Python versions for ast.parse() with feature_version set to 6 or lower).

버전 3.13에서 변경: Removed AWAIT and ASYNC tokens again.

keyword — Testing for Python keywords

소스 코드: Lib/keyword.py [https://github.com/python/cpython/tree/main/Lib/keyword.py]

This module allows a Python program to determine if a string is a keyword or soft keyword.

keyword.iskeyword(s)

s가 파이썬 키워드면 True를 반환합니다.

keyword.kwlist

인터프리터에 대해 정의된 모든 키워드를 포함하는 시퀀스. 특정 __future__ 문이 적용될 때만 활성화되도록 키워드가 정의되어 있으면, 이러한 키워드도 함께 포함됩니다.

keyword.issoftkeyword(s)

Return True if s is a Python soft keyword.

Added in version 3.9.

keyword.softkwlist

Sequence containing all the soft keywords defined for the interpreter. If any soft keywords are defined to only be active when particular __future__ statements are in effect, these will be included as well.

Added in version 3.9.

tokenize — Tokenizer for Python source

소스 코드: Lib/tokenize.py [https://github.com/python/cpython/tree/main/Lib/tokenize.py]

tokenize 모듈은 파이썬으로 구현된 파이썬 소스 코드를 위한 어휘 스캐너를 제공합니다. 이 모듈의 스캐너는 주석도 토큰으로 반환하므로, 화면 디스플레이용 색상 표시기를 포함하여 “예쁜 인쇄기”를 구현하는 데 유용합니다.

토큰 스트림 처리를 단순화하기 위해, 모든 연산자와 구분자 토큰과 Ellipsis는 범용 OP 토큰 유형을 사용하여 반환됩니다. 정확한 유형은 tokenize.tokenize()에서 반환된 네임드 튜플의 exact_type 프로퍼티를 확인하여 파악할 수 있습니다.

경고

Note that the functions in this module are only designed to parse syntactically valid Python code (code that does not raise when parsed using ast.parse()). The behavior of the functions in this module is undefined when providing invalid Python code and it can change at any point.

입력 토큰화하기

기본 진입점은 제너레이터입니다:

tokenize.tokenize(readline)

tokenize() 제너레이터는 하나의 인자 readline을 요구합니다. 이 인자는 파일 객체의 io.IOBase.readline() 메서드와 같은 인터페이스를 제공하는 콜러블 객체여야 합니다. 함수를 호출할 때마다 한 줄의 입력을 바이트열로 반환해야 합니다.

제너레이터는 다음 멤버를 갖는 5-튜플을 생성합니다: 토큰 유형; 토큰 문자열; 토큰이 소스에서 시작하는 줄과 열을 지정하는 정수의 2-튜플 (srow, scol); 토큰이 소스에서 끝나는 줄과 열을 지정하는 정수의 2-튜플 (erow, ecol)과 토큰이 발견된 줄. 전달된 줄(마지막 튜플 항목)은 물리적 줄입니다. 5-튜플은 필드 이름이 type string start end line 인 네임드 튜플로 반환됩니다.

반환된 네임드 튜플에는 OP 토큰에 대한 정확한 연산자 유형이 포함된 exact_type이라는 추가 프로퍼티가 있습니다. 다른 모든 토큰 유형에서 exact_type은 네임드 튜플 type 필드와 같습니다.

버전 3.1에서 변경: 네임드 튜플에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: exact_type에 대한 지원이 추가되었습니다.

tokenize()는 PEP 263 [https://peps.python.org/pep-0263/]에 따라 UTF-8 BOM이나 인코딩 쿠키를 찾아 파일의 소스 인코딩을 결정합니다.

tokenize.generate_tokens(readline)

바이트열 대신에 유니코드 문자열을 읽는 소스를 토큰화합니다.

tokenize()와 마찬가지로, readline 인자는 한 줄의 입력을 반환하는 콜러블입니다. 그러나, generate_tokens()는 readline이 바이트열이 아닌 문자열 객체를 반환할 것으로 기대합니다.

결과는 정확히 tokenize()처럼 네임드 튜플을 산출하는 이터레이터입니다. ENCODING 토큰을 산출하지 않습니다.

token 모듈의 모든 상수도 tokenize에서 내보냅니다.

토큰화 프로세스를 역전시키는 또 다른 함수가 제공됩니다. 이것은 스크립트를 토큰화하고, 토큰 스트림을 수정한 후, 수정된 스크립트를 다시 쓰는 도구를 만드는 데 유용합니다.

tokenize.untokenize(iterable)

토큰을 파이썬 소스 코드로 역 변환합니다. iterable은 최소한 토큰 유형과 토큰 문자열의 두 요소가 있는 시퀀스를 반환해야 합니다. 추가 시퀀스 요소는 무시됩니다.

재구성된 스크립트는 단일 문자열로 반환됩니다. 결과는 다시 토큰화하면 입력과 일치함이 보장되어, 변환은 무손실이고 왕복이 보장됩니다. 보증은 토큰 유형과 토큰 문자열에만 적용되어, 토큰 간의 간격(열 위치)은 변경될 수 있습니다.

tokenize() 에 의해 출력되는 첫 번째 토큰 시퀀스인 ENCODING 토큰을 사용하여 인코딩된 바이트열을 반환합니다. 입력에 인코딩 토큰이 없으면, 대신 str을 반환합니다.

tokenize()는 토큰화하는 소스 파일의 인코딩을 감지해야 합니다. 이 작업을 수행하는 데 사용되는 함수를 사용할 수 있습니다:

tokenize.detect_encoding(readline)

detect_encoding() 함수는 파이썬 소스 파일을 디코딩할 때 사용해야 하는 인코딩을 감지하는 데 사용됩니다. tokenize() 제너레이터와 같은 방식으로, 하나의 인자 readline을 요구합니다.

readline을 최대 두 번 호출하고, 사용된 인코딩(문자열로)과 읽은 줄들(바이트열에서 디코드 되지 않습니다)의 리스트를 반환합니다.

PEP 263 [https://peps.python.org/pep-0263/]에 지정된 대로 UTF-8 BOM이나 인코딩 쿠키의 존재로부터 인코딩을 검색합니다. BOM과 쿠키가 모두 있지만 서로 일치하지 않으면 SyntaxError가 발생합니다. BOM이 발견되면, 'utf-8-sig'가 인코딩으로 반환됩니다.

인코딩이 지정되지 않으면, 기본값인 'utf-8'이 반환됩니다.

open()을 사용하여 파이썬 소스 파일을 여십시오: detect_encoding()을 사용하여 파일 인코딩을 감지합니다.

tokenize.open(filename)

detect_encoding()에 의해 감지된 인코딩을 사용하여 읽기 전용 모드로 파일을 엽니다.

Added in version 3.2.

exception tokenize.TokenError

여러 줄로 나눌 수 있는 독스트링이나 표현식이 파일의 어디에서도 완료되지 않을 때 발생합니다, 예를 들어:

"""Beginning of
docstring

또는:

[1,
 2,
 3

명령 줄 사용법

Added in version 3.3.

tokenize 모듈은 명령 줄에서 스크립트로 실행될 수 있습니다. 이렇게 간단합니다:

python -m tokenize [-e] [filename.py]

허용되는 옵션은 다음과 같습니다:

-h, --help

이 도움말 메시지를 표시하고 종료합니다

-e, --exact

정확한 유형(exact_type)을 사용하여 토큰 이름을 표시합니다

filename.py가 지정되면 그 내용은 표준출력(stdout)으로 토큰화됩니다. 그렇지 않으면, 표준입력(stdin)에 대해 토큰화가 수행됩니다.

예제

float 리터럴을 Decimal 객체로 변환하는 스크립트 재 작성기의 예제:

from tokenize import tokenize, untokenize, NUMBER, STRING, NAME, OP
from io import BytesIO

def decistmt(s):
    """Substitute Decimals for floats in a string of statements.

    >>> from decimal import Decimal
    >>> s = 'print(+21.3e-5*-.1234/81.7)'
    >>> decistmt(s)
    "print (+Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7'))"

    The format of the exponent is inherited from the platform C library.
    Known cases are "e-007" (Windows) and "e-07" (not Windows).  Since
    we're only showing 12 digits, and the 13th isn't close to 5, the
    rest of the output should be platform-independent.

    >>> exec(s)  #doctest: +ELLIPSIS
    -3.21716034272e-0...7

    Output from calculations with Decimal should be identical across all
    platforms.

    >>> exec(decistmt(s))
    -3.217160342717258261933904529E-7
    """
    result = []
    g = tokenize(BytesIO(s.encode('utf-8')).readline)  # tokenize the string
    for toknum, tokval, _, _, _ in g:
        if toknum == NUMBER and '.' in tokval:  # replace NUMBER tokens
            result.extend([
                (NAME, 'Decimal'),
                (OP, '('),
                (STRING, repr(tokval)),
                (OP, ')')
            ])
        else:
            result.append((toknum, tokval))
    return untokenize(result).decode('utf-8')

명령 줄에서 토큰화하는 예제. 스크립트:

def say_hello():
    print("Hello, World!")

say_hello()

는 다음 출력으로 토큰화됩니다. 여기서 첫 번째 열은 토큰이 발견된 줄/열 좌표의 범위이고, 두 번째 열은 토큰의 이름이며, 마지막 열은 토큰의 값입니다 (있다면)

$ python -m tokenize hello.py
0,0-0,0:            ENCODING       'utf-8'
1,0-1,3:            NAME           'def'
1,4-1,13:           NAME           'say_hello'
1,13-1,14:          OP             '('
1,14-1,15:          OP             ')'
1,15-1,16:          OP             ':'
1,16-1,17:          NEWLINE        '\n'
2,0-2,4:            INDENT         '    '
2,4-2,9:            NAME           'print'
2,9-2,10:           OP             '('
2,10-2,25:          STRING         '"Hello, World!"'
2,25-2,26:          OP             ')'
2,26-2,27:          NEWLINE        '\n'
3,0-3,1:            NL             '\n'
4,0-4,0:            DEDENT         ''
4,0-4,9:            NAME           'say_hello'
4,9-4,10:           OP             '('
4,10-4,11:          OP             ')'
4,11-4,12:          NEWLINE        '\n'
5,0-5,0:            ENDMARKER      ''

정확한 토큰 유형 이름은 -e 옵션을 사용하여 표시할 수 있습니다:

$ python -m tokenize -e hello.py
0,0-0,0:            ENCODING       'utf-8'
1,0-1,3:            NAME           'def'
1,4-1,13:           NAME           'say_hello'
1,13-1,14:          LPAR           '('
1,14-1,15:          RPAR           ')'
1,15-1,16:          COLON          ':'
1,16-1,17:          NEWLINE        '\n'
2,0-2,4:            INDENT         '    '
2,4-2,9:            NAME           'print'
2,9-2,10:           LPAR           '('
2,10-2,25:          STRING         '"Hello, World!"'
2,25-2,26:          RPAR           ')'
2,26-2,27:          NEWLINE        '\n'
3,0-3,1:            NL             '\n'
4,0-4,0:            DEDENT         ''
4,0-4,9:            NAME           'say_hello'
4,9-4,10:           LPAR           '('
4,10-4,11:          RPAR           ')'
4,11-4,12:          NEWLINE        '\n'
5,0-5,0:            ENDMARKER      ''

generate_tokens()로 바이트열 대신 유니코드 문자열을 읽는, 프로그래밍 방식으로 파일을 토큰화하는 예:

import tokenize

with tokenize.open('hello.py') as f:
    tokens = tokenize.generate_tokens(f.readline)
    for token in tokens:
        print(token)

또는 tokenize()로 직접 바이트열을 읽는 예:

import tokenize

with open('hello.py', 'rb') as f:
    tokens = tokenize.tokenize(f.readline)
    for token in tokens:
        print(token)

tabnanny — Detection of ambiguous indentation

소스 코드: Lib/tabnanny.py [https://github.com/python/cpython/tree/main/Lib/tabnanny.py]

이 모듈은 당장은 스크립트로 호출하기 위한 것입니다. 하지만 IDE로 임포트 해서 아래에 설명된 check() 함수를 사용할 수 있습니다.

참고

이 모듈에서 제공하는 API는 향후 배포에서 변경될 수 있습니다; 그러한 변경은 이전 버전과 호환되지 않을 수 있습니다.

tabnanny.check(file_or_dir)

file_or_dir가 디렉터리이고 심볼릭 링크가 아니면, file_or_dir라는 이름의 디렉터리 트리를 재귀적으로 내려가면서, 모든 .py 파일을 검사합니다. file_or_dir가 일반 파이썬 소스 파일이면, 공백과 관련된 문제가 있는지 확인합니다. 진단 메시지는 print() 함수를 사용하여 표준 출력에 기록됩니다.

tabnanny.verbose

상세 메시지를 인쇄할지를 나타내는 플래그. 이것은 스크립트로 호출되면 -v 옵션에 의해 증가합니다.

tabnanny.filename_only

공백 관련 문제가 있는 파일의 파일명만 인쇄할지를 나타내는 플래그. 이것은 스크립트로 호출되면 -q 옵션에 의해 참으로 설정됩니다.

exception tabnanny.NannyNag

모호한 들여쓰기를 감지하면 process_tokens()에 의해 발생합니다. check()에서 잡아서 처리됩니다.

tabnanny.process_tokens(tokens)

이 함수는 tokenize 모듈에서 생성된 토큰을 처리하기 위해 check()에서 사용됩니다.

더 보기

모듈 tokenize

파이썬 소스 코드를 위한 어휘 스캐너.

pyclbr — Python module browser support

소스 코드: Lib/pyclbr.py [https://github.com/python/cpython/tree/main/Lib/pyclbr.py]

pyclbr 모듈은 파이썬 코드 모듈에 정의된 함수, 클래스 및 메서드에 대한 제한된 정보를 제공합니다. 이 정보는 모듈 브라우저를 구현하기에 충분합니다. 정보는 모듈을 임포트 하기보다는 파이썬 소스 코드에서 추출되므로 이 모듈은 신뢰할 수 없는 코드와 함께 사용하는 것이 안전합니다. 이 제한으로 인해 이 모듈을 모든 표준 및 선택 확장 모듈을 포함하여 파이썬으로 구현되지 않은 모듈에 사용할 수 없습니다.

pyclbr.readmodule(module, path=None)

모듈 수준의 클래스 이름을 클래스 설명자에 매핑하는 딕셔너리를 돌려줍니다. 가능하면, 임포트 된 베이스 클래스에 관한 설명자가 포함됩니다. 매개 변수 module은 읽을 모듈 이름이 들어있는 문자열입니다; 패키지 내의 모듈 이름일 수 있습니다. 주어지면, path는 sys.path 앞에 추가된 디렉터리 경로 시퀀스인데, 모듈 소스 코드의 위치를 찾는 데 사용됩니다.

이 함수는 원래 인터페이스이며 이전 버전과의 호환성을 위해서만 유지됩니다. 다음 함수의 필터링 된 버전을 반환합니다.

pyclbr.readmodule_ex(module, path=None)

def 나 class 문을 사용하여 모듈에 정의된 각 함수 및 클래스에 대한 함수나 클래스 설명자를 포함하는 딕셔너리 기반 트리를 반환합니다. 반환된 딕셔너리는 모듈 수준의 함수와 클래스 이름을 해당 설명자에 대응합니다. 중첩된 객체는 그들의 parent의 children 딕셔너리에 들어갑니다. readmodule과 마찬가지로, module은 읽을 모듈의 이름을 지정하고 path는 sys.path의 앞에 추가됩니다. 읽히는 모듈이 패키지면, 반환된 딕셔너리는 키 '__path__'를 가지는데, 값은 패키지 검색 경로를 포함하는 리스트입니다.

Added in version 3.7: 중첩된 정의에 대한 설명자. 새로운 children 어트리뷰트를 통해 액세스할 수 있습니다. 각에는 새로운 parent 어트리뷰트가 있습니다.

이러한 함수에 의해 반환되는 설명자는 Function과 Class 클래스의 인스턴스입니다. 사용자가 이러한 클래스의 인스턴스를 만들 것으로 기대하지 않습니다.

Function 객체

class pyclbr.Function

Class Function instances describe functions defined by def statements. They have the following attributes:

file

함수가 정의된 파일의 이름.

module

설명된 함수를 정의하는 모듈의 이름.

name

함수의 이름.

lineno

정의가 시작되는 파일의 줄 번호.

parent

For top-level functions, None. For nested functions, the parent.

Added in version 3.7.

children

A dictionary mapping names to descriptors for nested functions and classes.

Added in version 3.7.

is_async

True for functions that are defined with the async prefix, False otherwise.

Added in version 3.10.

Class 객체

class pyclbr.Class

Class Class instances describe classes defined by class statements. They have the same attributes as Functions and two more.

file

클래스가 정의된 파일의 이름.

module

설명된 클래스를 정의하는 모듈의 이름.

name

클래스의 이름.

lineno

정의가 시작되는 파일의 줄 번호.

parent

For top-level classes, None. For nested classes, the parent.

Added in version 3.7.

children

이름을 중첩된 함수와 클래스에 관한 설명자로 매핑하는 딕셔너리.

Added in version 3.7.

super

A list of Class objects which describe the immediate base classes of the class being described. Classes which are named as superclasses but which are not discoverable by readmodule_ex() are listed as a string with the class name instead of as Class objects.

methods

A dictionary mapping method names to line numbers. This can be derived from the newer children dictionary, but remains for back-compatibility.

py_compile — Compile Python source files

소스 코드: Lib/py_compile.py [https://github.com/python/cpython/tree/main/Lib/py_compile.py]

py_compile 모듈은 소스 파일에서 바이트 코드 파일을 생성하는 함수와 모듈 소스 파일이 스크립트로 호출될 때 사용되는 또 다른 함수를 제공합니다.

자주 사용되지는 않지만, 특히 일부 사용자가 소스 코드가 들어있는 디렉터리에 바이트 코드 캐시 파일을 쓸 수 있는 권한이 없을 때, 이 함수는 공유 사용을 위해 모듈을 설치할 때 유용할 수 있습니다.

exception py_compile.PyCompileError

파일을 컴파일하는 도중 에러가 일어날 때 발생하는 예외.

py_compile.compile(file, cfile=None, dfile=None, doraise=False, optimize=-1, invalidation_mode=PycInvalidationMode.TIMESTAMP, quiet=0)

Compile a source file to byte-code and write out the byte-code cache file. The source code is loaded from the file named file. The byte-code is written to cfile, which defaults to the PEP 3147 [https://peps.python.org/pep-3147/]/PEP 488 [https://peps.python.org/pep-0488/] path, ending in .pyc. For example, if file is /foo/bar/baz.py cfile will default to /foo/bar/__pycache__/baz.cpython-32.pyc for Python 3.2. If dfile is specified, it is used instead of file as the name of the source file from which source lines are obtained for display in exception tracebacks. If doraise is true, a PyCompileError is raised when an error is encountered while compiling file. If doraise is false (the default), an error string is written to sys.stderr, but no exception is raised. This function returns the path to byte-compiled file, i.e. whatever cfile value was used.

doraise와 quiet 인자는 파일을 컴파일하는 동안 에러를 처리하는 방법을 결정합니다. quiet가 0이나 1이고, doraise가 거짓이면, 기본 동작이 활성화됩니다: 에러 문자열이 sys.stderr에 기록되고, 함수는 경로 대신 None을 반환합니다. doraise가 참이면, 대신 PyCompileError가 발생합니다. 그러나 quiet가 2이면, 아무런 메시지도 기록되지 않고, doraise는 효과가 없습니다.

cfile이 되는 경로(명시적으로 지정되거나 계산된 경로)가 심볼릭 링크나 비정규 파일이면, FileExistsError가 발생합니다. 이것은 바이트 컴파일된 파일을 해당 경로에 쓸 수 있을 때 임포트가 해당 경로를 일반 파일로 바꾼다는 경고로 작용합니다. 이는 동시 파일 기록 문제를 방지하기 위해 최종 바이트 컴파일된 파일을 위치시키는데 파일 이름 바꾸기를 사용하는 임포트의 부작용입니다.

optimize는 최적화 수준을 제어하고 내장 compile() 함수로 전달됩니다. 기본값 -1은 현재 인터프리터의 최적화 수준을 선택합니다.

invalidation_mode는 PycInvalidationMode enum의 멤버여야 하며 실행 시간에 생성된 바이트 코드 캐시를 무효로 하는 방법을 제어합니다. SOURCE_DATE_EPOCH 환경 변수가 설정되면 기본값은 PycInvalidationMode.CHECKED_HASH이고, 그렇지 않으면 기본값은 PycInvalidationMode.TIMESTAMP입니다.

버전 3.2에서 변경: cfile의 기본값을 PEP 3147 [https://peps.python.org/pep-3147/]과 호환되도록 변경했습니다. 이전 기본값은 file + 'c'(최적화가 활성화되었으면 'o')입니다. 또한 optimize 매개 변수가 추가되었습니다.

버전 3.4에서 변경: 바이트 코드 캐시 파일 쓰기에 importlib를 사용하도록 코드를 변경했습니다. 이것은 파일 생성/기록 의미가 이제 importlib가 하는 것과 일치한다는 것을 의미합니다, 예를 들어 권한, 쓰기-와-이동 의미 등. 또한, cfile이 심볼릭 링크나 비정규 파일이면 FileExistsError가 발생시키는 경고를 추가했습니다.

버전 3.7에서 변경: invalidation_mode 매개 변수가 PEP 552 [https://peps.python.org/pep-0552/]에 지정된 대로 추가되었습니다. SOURCE_DATE_EPOCH 환경 변수가 설정되면, invalidation_mode는 PycInvalidationMode.CHECKED_HASH로 강제 설정됩니다.

버전 3.7.2에서 변경: SOURCE_DATE_EPOCH 환경 변수는 더는 invalidation_mode 인자의 값을 재정의하지 않으며, 대신 기본값을 결정합니다.

버전 3.8에서 변경: quiet 매개 변수가 추가되었습니다.

class py_compile.PycInvalidationMode

An enumeration of possible methods the interpreter can use to determine whether a bytecode file is up to date with a source file. The .pyc file indicates the desired invalidation mode in its header. See 캐시된 바이트 코드 무효화 for more information on how Python invalidates .pyc files at runtime.

Added in version 3.7.

TIMESTAMP

.pyc 파일은 파이썬이 실행 시간에 소스 파일의 메타 데이터와 비교하여 .pyc 파일을 재생성해야 하는지를 결정할 소스 파일의 타임스탬프와 크기를 포함합니다.

CHECKED_HASH

.pyc 파일은 파이썬이 실행 시간에 소스와 비교하여 .pyc 파일을 다시 생성해야 하는지를 결정할 소스 파일 내용의 해시를 포함합니다.

UNCHECKED_HASH

CHECKED_HASH와 마찬가지로, .pyc 파일에는 소스 파일 내용의 해시가 포함됩니다. 하지만, 파이썬은 실행 시간에 .pyc 파일이 최신 버전이라고 가정하고, 소스 파일에 대해 .pyc를 전혀 검증하지 않습니다.

이 옵션은 .pycs가 빌드 시스템처럼 파이썬 외부 시스템에 의해 최신 상태로 유지될 때 유용합니다.

Command-Line Interface

This module can be invoked as a script to compile several source files. The files named in filenames are compiled and the resulting bytecode is cached in the normal manner. This program does not search a directory structure to locate source files; it only compiles files named explicitly. The exit status is nonzero if one of the files could not be compiled.

<file> ... <fileN>

-

Positional arguments are files to compile. If - is the only parameter, the list of files is taken from standard input.

-q, --quiet

Suppress errors output.

버전 3.2에서 변경: Added support for -.

버전 3.10에서 변경: Added support for -q.

더 보기

모듈 compileall

디렉터리 트리에 있는 모든 파이썬 소스 파일을 컴파일하는 유틸리티.

compileall — Byte-compile Python libraries

소스 코드: Lib/compileall.py [https://github.com/python/cpython/tree/main/Lib/compileall.py]

이 모듈은 파이썬 라이브러리 설치를 지원하는 몇 가지 유틸리티 함수를 제공합니다. 이 함수는 디렉터리 트리에서 파이썬 소스 파일을 컴파일합니다. 이 모듈을 사용하면 라이브러리 설치 시 캐시 된 바이트 코드 파일을 만들 수 있으므로, 라이브러리 디렉터리에 쓰기 권한이 없는 사용자도 사용할 수 있도록 합니다.

Availability: not WASI.

This module does not work or is not available on WebAssembly. See WebAssembly platforms for more information.

명령 줄 사용

이 모듈은 파이썬 소스를 컴파일하는 스크립트로 작동할 수 있습니다 (python -m compileall을 사용합니다).

directory ...

file ...

Positional arguments are files to compile or directories that contain source files, traversed recursively. If no argument is given, behave as if the command line was -l <directories from sys.path>.

-l

서브 디렉터리를 재귀적으로 탐색하지 않고, 이름이 지정되었거나 암시된 디렉터리에 직접 포함된 소스 코드 파일 만 컴파일합니다.

-f

타임스탬프가 최신일 때도 강제로 다시 빌드합니다.

-q

컴파일된 파일 목록을 인쇄하지 않습니다. 한 번 전달하면, 에러 메시지는 여전히 인쇄됩니다. 두 번 전달하면 (-qq), 모든 출력이 억제됩니다.

-d destdir

디렉터리가 컴파일되는 각 파일의 경로 앞에 추가됩니다. 이것은 컴파일 시간 트레이스백에 나타나며, 바이트 코드 파일에 컴파일되어 들어가서, 바이트 코드 파일이 실행되는 시점에 소스 파일이 존재하지 않으면 트레이스백과 기타 메시지에 사용됩니다.

-s strip_prefix

-p prepend_prefix

.pyc 파일에 기록된 지정된 경로 접두사를 제거(-s)하거나 추가(-p)합니다. -d와 함께 사용할 수 없습니다.

-x regex

regex는 컴파일 대상으로 고려되는 각 파일의 전체 경로를 검색(search)하는 데 사용되며, 정규식이 일치를 생성하면 그 파일을 건너뜁니다.

-i list

파일 list를 읽고 포함된 각 줄을 컴파일할 파일과 디렉터리 목록에 추가합니다. list가 -이면, stdin에서 줄을 읽습니다.

-b

바이트 코드 파일을 레거시 위치 및 이름에 써서, 다른 버전의 파이썬이 만든 바이트 코드 파일을 덮어쓸 수 있습니다. 기본값은 여러 버전의 파이썬의 바이트 코드 파일이 공존할 수 있는 PEP 3147 [https://peps.python.org/pep-3147/] 위치와 이름에 파일을 쓰는 것입니다.

-r

서브 디렉터리의 최대 재귀 수준을 제어합니다. 이것이 주어지면, -l 옵션은 고려되지 않습니다. python -m compileall <directory> -r 0은 python -m compileall <directory> -l과 동등합니다.

-j N

Use N workers to compile the files within the given directory. If 0 is used, then the result of os.process_cpu_count() will be used.

--invalidation-mode [timestamp|checked-hash|unchecked-hash]

생성된 바이트 코드 파일이 실행 시간에 무효가 되는 방식을 제어합니다. timestamp 값은 소스 타임스탬프와 크기가 포함된 .pyc 파일이 생성됨을 의미합니다. checked-hash와 unchecked-hash 값은 해시 기반 pyc를 생성합니다. 해시 기반 pyc는 타임스탬프 대신 소스 파일 내용의 해시를 포함합니다. 파이썬이 실행 시간에 바이트 코드 캐시 파일의 유효성을 검사하는 방법에 대한 자세한 내용은 캐시된 바이트 코드 무효화를 참조하십시오. 기본값은 SOURCE_DATE_EPOCH 환경 변수가 설정되지 않으면 timestamp이고, SOURCE_DATE_EPOCH 환경 변수가 설정되면 checked-hash입니다.

-o level

주어진 최적화 수준으로 컴파일합니다. 한 번에 여러 수준으로 컴파일하기 위해 여러 번 사용할 수 있습니다 (예를 들어, compileall -o 1 -o 2).

-e dir

지정된 디렉터리 외부를 가리키는 심볼릭 링크를 무시합니다.

--hardlink-dupes

최적화 수준이 다른 두 개의 .pyc 파일의 내용이 같으면, 하드 링크를 사용하여 중복 파일을 통합합니다.

버전 3.2에서 변경: -i, -b 및 -h 옵션이 추가되었습니다.

버전 3.5에서 변경: -j, -r 및 -qq 옵션이 추가되었습니다. -q 옵션이 다중 수준 값으로 변경되었습니다. -b는 항상 .pyc로 끝나는 바이트 코드 파일을 생성하며, 결코 .pyo를 생성하지 않습니다.

버전 3.7에서 변경: --invalidation-mode 옵션이 추가되었습니다.

버전 3.9에서 변경: -s, -p, -e 및 --hardlink-dupes 옵션을 추가했습니다. 기본 재귀 제한을 10에서 sys.getrecursionlimit()로 올렸습니다. -o 옵션을 여러 번 지정할 수 있는 가능성이 추가되었습니다.

compile() 함수가 사용하는 최적화 수준을 제어하는 명령 줄 옵션은 없습니다. 파이썬 인터프리터 자신이 그 옵션을 제공하고 있기 때문입니다: python -O -m compileall.

Similarly, the compile() function respects the sys.pycache_prefix setting. The generated bytecode cache will only be useful if compile() is run with the same sys.pycache_prefix (if any) that will be used at runtime.

공용 함수

compileall.compile_dir(dir, maxlevels=sys.getrecursionlimit(), ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1, invalidation_mode=None, *, stripdir=None, prependdir=None, limit_sl_dest=None, hardlink_dupes=False)

dir로 명명된 디렉터리 트리를 재귀적으로 탐색해 내려가면서, 발견되는 모든 .py 파일을 컴파일합니다. 모든 파일이 성공적으로 컴파일되면 참값을 반환하고, 그렇지 않으면 거짓값을 반환합니다.

maxlevels 매개 변수는 재귀의 깊이를 제한하는 데 사용됩니다; 기본값은 sys.getrecursionlimit()입니다.

ddir이 주어지면, 컴파일 시간 트레이스백에서 사용하기 위해 컴파일되는 각 파일의 경로 앞에 추가되며, 바이트 코드 파일에 컴파일되어 들어가서, 바이트 코드 파일이 실행되는 시점에 소스 파일이 존재하지 않으면 트레이스백과 기타 메시지에 사용됩니다.

force가 참이면, 타임스탬프가 최신일 때도 모듈이 다시 컴파일됩니다.

If rx is given, its search method is called on the complete path to each file considered for compilation, and if it returns a true value, the file is skipped. This can be used to exclude files matching a regular expression, given as a re.Pattern object.

quiet가 False나 0(기본값)이면, 파일명과 기타 정보가 표준 출력에 인쇄됩니다. 1로 설정하면, 에러만 인쇄됩니다. 2로 설정하면, 모든 출력이 억제됩니다.

legacy가 참이면, 바이트 코드 파일을 레거시 위치 및 이름에 써서, 다른 버전의 파이썬이 만든 바이트 코드 파일을 덮어쓸 수 있습니다. 기본값은 여러 버전의 파이썬의 바이트 코드 파일이 공존할 수 있는 PEP 3147 [https://peps.python.org/pep-3147/] 위치와 이름에 파일을 쓰는 것입니다.

optimize는 컴파일러의 최적화 수준을 지정합니다. 내장 compile() 함수로 전달됩니다. 한 번의 호출로 하나의 .py 파일을 여러 번 컴파일하도록 하는 최적화 수준의 시퀀스도 허용합니다.

인자 workers는 파일을 컴파일하는 데 병렬로 사용되는 작업자 수를 지정합니다. 기본값은 다중 작업자를 사용하지 않는 것입니다. 플랫폼이 다중 작업자를 사용할 수 없고 workers 인자가 주어지면, 순차 컴파일로 대체합니다. workers가 0이면 시스템의 코어 수가 사용됩니다. workers가 0보다 작으면, ValueError가 발생합니다.

invalidation_mode는 py_compile.PycInvalidationMode 열거형의 멤버여야 하며 실행 시간에 생성된 pyc가 무효가 되는 방식을 제어합니다.

The stripdir, prependdir and limit_sl_dest arguments correspond to the -s, -p and -e options described above. They may be specified as str or os.PathLike.

hardlink_dupes가 참이고 최적화 수준이 다른 두 개의 .pyc 파일의 내용이 같으면, 하드 링크를 사용하여 중복 파일을 통합합니다.

버전 3.2에서 변경: legacy와 optimize 매개 변수가 추가되었습니다.

버전 3.5에서 변경: workers 매개 변수가 추가되었습니다.

버전 3.5에서 변경: quiet 매개 변수가 다중 수준 값으로 변경되었습니다.

버전 3.5에서 변경: legacy 매개 변수는 optimize 값과 상관없이 .pyo 파일이 아니라 .pyc 파일 만 기록합니다.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

버전 3.7에서 변경: invalidation_mode 매개 변수가 추가되었습니다.

버전 3.7.2에서 변경: The invalidation_mode parameter’s default value is updated to None.

버전 3.8에서 변경: workers를 0으로 설정하면 최적의 코어 수가 선택됩니다.

버전 3.9에서 변경: stripdir, prependdir, limit_sl_dest 및 hardlink_dupes 인자가 추가되었습니다. maxlevels의 기본값이 10에서 sys.getrecursionlimit()으로 변경되었습니다.

compileall.compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, invalidation_mode=None, *, stripdir=None, prependdir=None, limit_sl_dest=None, hardlink_dupes=False)

경로 fullname의 파일을 컴파일합니다. 파일이 성공적으로 컴파일되면 참값을 반환하고, 그렇지 않으면 거짓값을 반환합니다.

ddir이 주어지면, 컴파일 시간 트레이스백에서 사용하기 위해 컴파일되는 파일의 경로 앞에 추가되며, 바이트 코드 파일에 컴파일되어 들어가서, 바이트 코드 파일이 실행되는 시점에 소스 파일이 존재하지 않으면 트레이스백과 기타 메시지에 사용됩니다.

If rx is given, its search method is passed the full path name to the file being compiled, and if it returns a true value, the file is not compiled and True is returned. This can be used to exclude files matching a regular expression, given as a re.Pattern object.

quiet가 False나 0(기본값)이면, 파일명과 기타 정보가 표준 출력에 인쇄됩니다. 1로 설정하면, 에러만 인쇄됩니다. 2로 설정하면, 모든 출력이 억제됩니다.

legacy가 참이면, 바이트 코드 파일을 레거시 위치 및 이름에 써서, 다른 버전의 파이썬이 만든 바이트 코드 파일을 덮어쓸 수 있습니다. 기본값은 여러 버전의 파이썬의 바이트 코드 파일이 공존할 수 있는 PEP 3147 [https://peps.python.org/pep-3147/] 위치와 이름에 파일을 쓰는 것입니다.

optimize는 컴파일러의 최적화 수준을 지정합니다. 내장 compile() 함수로 전달됩니다. 한 번의 호출로 하나의 .py 파일을 여러 번 컴파일하도록 하는 최적화 수준의 시퀀스도 허용합니다.

invalidation_mode는 py_compile.PycInvalidationMode 열거형의 멤버여야 하며 실행 시간에 생성된 pyc가 무효가 되는 방식을 제어합니다.

The stripdir, prependdir and limit_sl_dest arguments correspond to the -s, -p and -e options described above. They may be specified as str or os.PathLike.

hardlink_dupes가 참이고 최적화 수준이 다른 두 개의 .pyc 파일의 내용이 같으면, 하드 링크를 사용하여 중복 파일을 통합합니다.

Added in version 3.2.

버전 3.5에서 변경: quiet 매개 변수가 다중 수준 값으로 변경되었습니다.

버전 3.5에서 변경: legacy 매개 변수는 optimize 값과 상관없이 .pyo 파일이 아니라 .pyc 파일 만 기록합니다.

버전 3.7에서 변경: invalidation_mode 매개 변수가 추가되었습니다.

버전 3.7.2에서 변경: The invalidation_mode parameter’s default value is updated to None.

버전 3.9에서 변경: stripdir, prependdir, limit_sl_dest 및 hardlink_dupes 인자가 추가되었습니다.

compileall.compile_path(skip_curdir=True, maxlevels=0, force=False, quiet=0, legacy=False, optimize=-1, invalidation_mode=None)

sys.path에서 발견된 모든 .py 파일을 바이트 컴파일합니다. 모든 파일이 성공적으로 컴파일되면 참값을 반환하고, 그렇지 않으면 거짓값을 반환합니다.

skip_curdir가 참(기본값)이면, 현재 디렉터리가 검색에 포함되지 않습니다. 다른 모든 매개 변수는 compile_dir() 함수에 전달됩니다. 다른 컴파일 함수와 달리, maxlevels의 기본값은 0임에 유의하십시오.

버전 3.2에서 변경: legacy와 optimize 매개 변수가 추가되었습니다.

버전 3.5에서 변경: quiet 매개 변수가 다중 수준 값으로 변경되었습니다.

버전 3.5에서 변경: legacy 매개 변수는 optimize 값과 상관없이 .pyo 파일이 아니라 .pyc 파일 만 기록합니다.

버전 3.7에서 변경: invalidation_mode 매개 변수가 추가되었습니다.

버전 3.7.2에서 변경: The invalidation_mode parameter’s default value is updated to None.

Lib/ 서브 디렉터리와 그것의 모든 서브 디렉터리에 있는 모든 .py 파일을 강제로 다시 컴파일하려면 다음과 같이 합니다:

import compileall

compileall.compile_dir('Lib/', force=True)

# Perform same compilation, excluding files in .svn directories.
import re
compileall.compile_dir('Lib/', rx=re.compile(r'[/\\][.]svn'), force=True)

# pathlib.Path objects can also be used.
import pathlib
compileall.compile_dir(pathlib.Path('Lib/'), force=True)

더 보기

모듈 py_compile

단일 소스 파일을 바이트 컴파일합니다.

dis — Disassembler for Python bytecode

소스 코드: Lib/dis.py [https://github.com/python/cpython/tree/main/Lib/dis.py]

dis 모듈은 CPython 바이트 코드를 역 어셈블 하여 분석을 지원합니다. 이 모듈이 입력으로 취하는 CPython 바이트 코드는 파일 Include/opcode.h에 정의되어 있으며 컴파일러와 인터프리터에서 사용됩니다.

CPython 구현 상세: 바이트 코드는 CPython 인터프리터의 구현 세부 사항입니다. 파이썬 버전 간에 바이트 코드가 추가, 제거 또는 변경되지 않을 것이라는 보장은 없습니다. 이 모듈을 사용하는 것이 파이썬 VM이나 파이썬 릴리스에 걸쳐 작동할 것으로 생각하지 말아야 합니다.

버전 3.6에서 변경: 명령어마다 2바이트를 사용합니다. 이전에는 바이트 수가 명령어에 따라 달랐습니다.

버전 3.10에서 변경: The argument of jump, exception handling and loop instructions is now the instruction offset rather than the byte offset.

버전 3.11에서 변경: Some instructions are accompanied by one or more inline cache entries, which take the form of CACHE instructions. These instructions are hidden by default, but can be shown by passing show_caches=True to any dis utility. Furthermore, the interpreter now adapts the bytecode to specialize it for different runtime conditions. The adaptive bytecode can be shown by passing adaptive=True.

버전 3.12에서 변경: The argument of a jump is the offset of the target instruction relative to the instruction that appears immediately after the jump instruction’s CACHE entries.

As a consequence, the presence of the CACHE instructions is transparent for forward jumps but needs to be taken into account when reasoning about backward jumps.

버전 3.13에서 변경: The output shows logical labels rather than instruction offsets for jump targets and exception handlers. The -O command line option and the show_offsets argument were added.

버전 3.14에서 변경: The -P command-line option and the show_positions argument were added.

Example: Given the function myfunc():

def myfunc(alist):
    return len(alist)

the following command can be used to display the disassembly of myfunc():

>>> dis.dis(myfunc)
  2           RESUME                   0

  3           LOAD_GLOBAL              1 (len + NULL)
              LOAD_FAST                0 (alist)
              CALL                     1
              RETURN_VALUE

(“2”는 줄 번호입니다).

Command-line interface

The dis module can be invoked as a script from the command line:

python -m dis [-h] [-C] [-O] [-P] [infile]

The following options are accepted:

-h, --help

Display usage and exit.

-C, --show-caches

Show inline caches.

-O, --show-offsets

Show offsets of instructions.

-P, --show-positions

Show positions of instructions in the source code.

If infile is specified, its disassembled code will be written to stdout. Otherwise, disassembly is performed on compiled source code received from stdin.

바이트 코드 분석

Added in version 3.4.

바이트 코드 분석 API는 컴파일된 코드의 세부 사항에 쉽게 액세스 할 수 있도록 하는 Bytecode 객체로 파이썬 코드 조각을 감쌀 수 있도록 합니다.

class dis.Bytecode(x, *, first_line=None, current_offset=None, show_caches=False, adaptive=False, show_offsets=False, show_positions=False)

함수, 제너레이터, 비동기 제너레이터, 코루틴, 메서드, 소스 코드 문자열 또는 (compile()에서 반환된) 코드 객체에 해당하는 바이트 코드를 분석합니다.

이것은 아래에 나열된 많은 함수, 특히 get_instructions()를 둘러싼 편리한 래퍼입니다, Bytecode 인스턴스를 이터레이트 하면 바이트 코드 연산이 Instruction 인스턴스로 산출되기 때문입니다.

first_line이 None이 아니면, 역 어셈블 된 코드에서 첫 번째 소스 줄에 대해 보고해야 하는 줄 번호를 나타냅니다. 그렇지 않으면, 소스 줄 정보(있다면)를 역 어셈블 된 코드 객체에서 직접 취합니다.

current_offset이 None이 아니면, 역 어셈블 된 코드의 명령어 오프셋을 나타냅니다. 이를 설정하면, dis()가 지정된 옵코드(opcode)에 대해 “현재 명령어” 마커를 표시합니다.

If show_caches is True, dis() will display inline cache entries used by the interpreter to specialize the bytecode.

If adaptive is True, dis() will display specialized bytecode that may be different from the original bytecode.

If show_offsets is True, dis() will include instruction offsets in the output.

If show_positions is True, dis() will include instruction source code positions in the output.

classmethod from_traceback(tb, *, show_caches=False)

주어진 트레이스백에서 Bytecode 인스턴스를 구성하고, current_offset을 예외를 일으킨 명령어로 설정합니다.

codeobj

컴파일된 코드 객체.

first_line

코드 객체의 첫 번째 소스 줄 (사용 가능하다면)

dis()

바이트 코드 연산의 포맷된 보기를 반환합니다 (dis.dis()가 인쇄하는 것과 같지만, 여러 줄 문자열로 반환됩니다).

info()

code_info()처럼, 코드 객체에 대한 자세한 정보가 포함된 포맷된 여러 줄 문자열을 반환합니다.

버전 3.7에서 변경: 이제 코루틴과 비동기 제너레이터 객체를 처리할 수 있습니다.

버전 3.11에서 변경: Added the show_caches and adaptive parameters.

버전 3.13에서 변경: Added the show_offsets parameter

버전 3.14에서 변경: Added the show_positions parameter.

Example:

>>> bytecode = dis.Bytecode(myfunc)
>>> for instr in bytecode:
...     print(instr.opname)
...
RESUME
LOAD_GLOBAL
LOAD_FAST
CALL
RETURN_VALUE

분석 함수

dis 모듈은 또한 입력을 원하는 출력으로 직접 변환하는 다음 분석 함수를 정의합니다. 단일 작업만 수행해서, 중간 분석 객체가 유용하지 않을 때 유용할 수 있습니다:

dis.code_info(x)

제공된 함수, 제너레이터, 비동기 제너레이터, 코루틴, 메서드, 소스 코드 문자열 또는 코드 객체에 대한 자세한 코드 객체 정보가 포함된 포맷된 여러 줄 문자열을 반환합니다.

코드 정보 문자열의 정확한 내용은 구현에 따라 달라지며 파이썬 VM이나 파이썬 릴리스에 걸쳐 임의로 변경될 수 있습니다.

Added in version 3.2.

버전 3.7에서 변경: 이제 코루틴과 비동기 제너레이터 객체를 처리할 수 있습니다.

dis.show_code(x, *, file=None)

제공된 함수, 메서드, 소스 코드 문자열 또는 코드 객체에 대한 자세한 코드 객체 정보를 file(또는 file이 지정되지 않으면 sys.stdout)로 인쇄합니다.

이것은 print(code_info(x), file=file)의 편리한 축약 형으로, 인터프리터 프롬프트에서의 대화식 탐색을 위한 것입니다.

Added in version 3.2.

버전 3.4에서 변경: file 매개 변수를 추가했습니다.

dis.dis(x=None, *, file=None, depth=None, show_caches=False, adaptive=False, show_offsets=False, show_positions=False)

Disassemble the x object. x can denote either a module, a class, a method, a function, a generator, an asynchronous generator, a coroutine, a code object, a string of source code or a byte sequence of raw bytecode. For a module, it disassembles all functions. For a class, it disassembles all methods (including class and static methods). For a code object or sequence of raw bytecode, it prints one line per bytecode instruction. It also recursively disassembles nested code objects. These can include generator expressions, nested functions, the bodies of nested classes, and the code objects used for annotation scopes. Strings are first compiled to code objects with the compile() built-in function before being disassembled. If no object is provided, this function disassembles the last traceback.

역 어셈블리는 제공된다면 제공된 file 인자에, 그렇지 않으면 sys.stdout에 텍스트로 기록됩니다.

재귀의 최대 깊이는 None이 아닌 한 depth에 의해 제한됩니다. depth=0은 재귀가 없음을 의미합니다.

If show_caches is True, this function will display inline cache entries used by the interpreter to specialize the bytecode.

If adaptive is True, this function will display specialized bytecode that may be different from the original bytecode.

버전 3.4에서 변경: file 매개 변수를 추가했습니다.

버전 3.7에서 변경: 재귀 역 어셈블을 구현하고 depth 매개 변수를 추가했습니다.

버전 3.7에서 변경: 이제 코루틴과 비동기 제너레이터 객체를 처리할 수 있습니다.

버전 3.11에서 변경: Added the show_caches and adaptive parameters.

버전 3.13에서 변경: Added the show_offsets parameter.

버전 3.14에서 변경: Added the show_positions parameter.

dis.distb(tb=None, *, file=None, show_caches=False, adaptive=False, show_offset=False, show_positions=False)

트레이스백의 최상단 함수를 역 어셈블 합니다. 전달되지 않으면 마지막 트레이스백을 사용합니다. 예외를 일으키는 명령어가 표시됩니다.

역 어셈블리는 제공된다면 제공된 file 인자에, 그렇지 않으면 sys.stdout에 텍스트로 기록됩니다.

버전 3.4에서 변경: file 매개 변수를 추가했습니다.

버전 3.11에서 변경: Added the show_caches and adaptive parameters.

버전 3.13에서 변경: Added the show_offsets parameter.

버전 3.14에서 변경: Added the show_positions parameter.

dis.disassemble(code, lasti=-1, *, file=None, show_caches=False, adaptive=False, show_offsets=False, show_positions=False)

dis.disco(code, lasti=-1, *, file=None, show_caches=False, adaptive=False, show_offsets=False, show_positions=False)

코드 객체를 역 어셈블 하고, lasti가 제공되면 마지막 명령어를 표시합니다. 출력은 다음 열로 나뉩니다:

the source code location of the instruction. Complete location information is shown if show_positions is true. Otherwise (the default) only the line number is displayed.

현재 명령어, -->로 표시됩니다,

레이블이 있는 명령어, >>로 표시됩니다,

명령어의 주소,

연산 코드 이름,

연산 매개 변수, 그리고

괄호 안에 있는 매개 변수의 해석.

매개 변수 해석은 지역과 전역 변수 이름, 상숫값, 분기 대상 및 비교 연산자를 인식합니다.

역 어셈블리는 제공된다면 제공된 file 인자에, 그렇지 않으면 sys.stdout에 텍스트로 기록됩니다.

버전 3.4에서 변경: file 매개 변수를 추가했습니다.

버전 3.11에서 변경: Added the show_caches and adaptive parameters.

버전 3.13에서 변경: Added the show_offsets parameter.

버전 3.14에서 변경: Added the show_positions parameter.

dis.get_instructions(x, *, first_line=None, show_caches=False, adaptive=False)

제공된 함수, 메서드, 소스 코드 문자열 또는 코드 객체의 명령어들에 대한 이터레이터를 반환합니다.

이터레이터는 제공된 코드의 각 연산에 대한 세부 정보를 제공하는 Instruction 네임드 튜플의 연속을 생성합니다.

first_line이 None이 아니면, 역 어셈블 된 코드에서 첫 번째 소스 줄에 대해 보고해야 하는 줄 번호를 나타냅니다. 그렇지 않으면, 소스 줄 정보(있다면)를 역 어셈블 된 코드 객체에서 직접 취합니다.

The adaptive parameter works as it does in dis().

Added in version 3.4.

버전 3.11에서 변경: Added the show_caches and adaptive parameters.

버전 3.13에서 변경: The show_caches parameter is deprecated and has no effect. The iterator generates the Instruction instances with the cache_info field populated (regardless of the value of show_caches) and it no longer generates separate items for the cache entries.

dis.findlinestarts(code)

This generator function uses the co_lines() method of the code object code to find the offsets which are starts of lines in the source code. They are generated as (offset, lineno) pairs.

버전 3.6에서 변경: 줄 번호가 줄어들 수 있습니다. 전에는, 언제나 증가했습니다.

버전 3.10에서 변경: The PEP 626 [https://peps.python.org/pep-0626/] co_lines() method is used instead of the co_firstlineno and co_lnotab attributes of the code object.

버전 3.13에서 변경: Line numbers can be None for bytecode that does not map to source lines.

dis.findlabels(code)

원시 컴파일된 바이트 코드 문자열 code에서 점프 대상인 모든 오프셋을 감지하고, 이러한 오프셋의 리스트를 반환합니다.

dis.stack_effect(opcode, oparg=None, *, jump=None)

인자 oparg를 갖는 opcode의 스택 효과를 계산합니다.

코드에 점프 대상이 있고 jump가 True이면, stack_effect()는 점프의 스택 효과를 반환합니다. jump가 False이면, 점프하지 않는 스택 효과를 반환합니다. jump가 None(기본값)이면, 두 경우의 최대 스택 효과를 반환합니다.

Added in version 3.4.

버전 3.8에서 변경: jump 매개 변수를 추가했습니다.

버전 3.13에서 변경: If oparg is omitted (or None), the stack effect is now returned for oparg=0. Previously this was an error for opcodes that use their arg. It is also no longer an error to pass an integer oparg when the opcode does not use it; the oparg in this case is ignored.

파이썬 바이트 코드 명령어

get_instructions() 함수와 Bytecode 클래스는 바이트 코드 명령어의 세부 사항을 Instruction 인스턴스로 제공합니다:

class dis.Instruction

바이트 코드 연산에 대한 세부 사항

opcode

연산의 숫자 코드, 아래 나열된 옵코드 값과 옵코드 모음에 있는 바이트 코드 값에 해당합니다.

opname

연산의 사람이 읽을 수 있는 이름

baseopcode

numeric code for the base operation if operation is specialized; otherwise equal to opcode

baseopname

human readable name for the base operation if operation is specialized; otherwise equal to opname

arg

연산에 대한 숫자 인자 (있다면), 그렇지 않으면 None

oparg

alias for arg

argval

resolved arg value (if any), otherwise None

argrepr

human readable description of operation argument (if any), otherwise an empty string.

offset

바이트 코드 시퀀스 내에서 연산의 시작 인덱스

start_offset

start index of operation within bytecode sequence, including prefixed EXTENDED_ARG operations if present; otherwise equal to offset

cache_offset

start index of the cache entries following the operation

end_offset

end index of the cache entries following the operation

starts_line

True if this opcode starts a source line, otherwise False

line_number

source line number associated with this opcode (if any), otherwise None

is_jump_target

다른 코드가 여기로 점프하면 True, 그렇지 않으면 False

jump_target

bytecode index of the jump target if this is a jump operation, otherwise None

positions

dis.Positions object holding the start and end locations that are covered by this instruction.

Added in version 3.4.

버전 3.11에서 변경: Field positions is added.

버전 3.13에서 변경: Changed field starts_line.

Added fields start_offset, cache_offset, end_offset, baseopname, baseopcode, jump_target, oparg, line_number and cache_info.

class dis.Positions

In case the information is not available, some fields might be None.

lineno

end_lineno

col_offset

end_col_offset

Added in version 3.11.

파이썬 컴파일러는 현재 다음 바이트 코드 명령어를 생성합니다.

일반 명령어

In the following, We will refer to the interpreter stack as STACK and describe operations on it as if it was a Python list. The top of the stack corresponds to STACK[-1] in this language.

NOP

Do nothing code. Used as a placeholder by the bytecode optimizer, and to generate line tracing events.

POP_TOP

Removes the top-of-stack item:

STACK.pop()

END_FOR

Removes the top-of-stack item. Equivalent to POP_TOP. Used to clean up at the end of loops, hence the name.

Added in version 3.12.

END_SEND

Implements del STACK[-2]. Used to clean up when a generator exits.

Added in version 3.12.

COPY(i)

Push the i-th item to the top of the stack without removing it from its original location:

assert i > 0
STACK.append(STACK[-i])

Added in version 3.11.

SWAP(i)

Swap the top of the stack with the i-th element:

STACK[-i], STACK[-1] = STACK[-1], STACK[-i]

Added in version 3.11.

CACHE

Rather than being an actual instruction, this opcode is used to mark extra space for the interpreter to cache useful data directly in the bytecode itself. It is automatically hidden by all dis utilities, but can be viewed with show_caches=True.

Logically, this space is part of the preceding instruction. Many opcodes expect to be followed by an exact number of caches, and will instruct the interpreter to skip over them at runtime.

Populated caches can look like arbitrary instructions, so great care should be taken when reading or modifying raw, adaptive bytecode containing quickened data.

Added in version 3.11.

단항 연산

단항 연산은 스택의 최상단을 취하고, 연산을 적용한 다음, 결과를 스택에 다시 푸시합니다.

UNARY_NEGATIVE

Implements STACK[-1] = -STACK[-1].

UNARY_NOT

Implements STACK[-1] = not STACK[-1].

버전 3.13에서 변경: This instruction now requires an exact bool operand.

UNARY_INVERT

Implements STACK[-1] = ~STACK[-1].

GET_ITER

Implements STACK[-1] = iter(STACK[-1]).

GET_YIELD_FROM_ITER

If STACK[-1] is a generator iterator or coroutine object it is left as is. Otherwise, implements STACK[-1] = iter(STACK[-1]).

Added in version 3.5.

TO_BOOL

Implements STACK[-1] = bool(STACK[-1]).

Added in version 3.13.

Binary and in-place operations

Binary operations remove the top two items from the stack (STACK[-1] and STACK[-2]). They perform the operation, then put the result back on the stack.

In-place operations are like binary operations, but the operation is done in-place when STACK[-2] supports it, and the resulting STACK[-1] may be (but does not have to be) the original STACK[-2].

BINARY_OP(op)

Implements the binary and in-place operators (depending on the value of op):

rhs = STACK.pop()
lhs = STACK.pop()
STACK.append(lhs op rhs)

Added in version 3.11.

BINARY_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
STACK.append(container[key])

STORE_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
value = STACK.pop()
container[key] = value

DELETE_SUBSCR

Implements:

key = STACK.pop()
container = STACK.pop()
del container[key]

BINARY_SLICE

Implements:

end = STACK.pop()
start = STACK.pop()
container = STACK.pop()
STACK.append(container[start:end])

Added in version 3.12.

STORE_SLICE

Implements:

end = STACK.pop()
start = STACK.pop()
container = STACK.pop()
values = STACK.pop()
container[start:end] = value

Added in version 3.12.

코루틴 옵코드

GET_AWAITABLE(where)

Implements STACK[-1] = get_awaitable(STACK[-1]), where get_awaitable(o) returns o if o is a coroutine object or a generator object with the CO_ITERABLE_COROUTINE flag, or resolves o.__await__.

If the where operand is nonzero, it indicates where the instruction occurs:

1: After a call to __aenter__

2: After a call to __aexit__

Added in version 3.5.

버전 3.11에서 변경: Previously, this instruction did not have an oparg.

GET_AITER

Implements STACK[-1] = STACK[-1].__aiter__().

Added in version 3.5.

버전 3.7에서 변경: __aiter__로부터 어웨이터블 객체를 반환하는 것은 더는 지원되지 않습니다.

GET_ANEXT

Implement STACK.append(get_awaitable(STACK[-1].__anext__())) to the stack. See GET_AWAITABLE for details about get_awaitable.

Added in version 3.5.

END_ASYNC_FOR

Terminates an async for loop. Handles an exception raised when awaiting a next item. The stack contains the async iterable in STACK[-2] and the raised exception in STACK[-1]. Both are popped. If the exception is not StopAsyncIteration, it is re-raised.

Added in version 3.8.

버전 3.11에서 변경: Exception representation on the stack now consist of one, not three, items.

CLEANUP_THROW

Handles an exception raised during a throw() or close() call through the current frame. If STACK[-1] is an instance of StopIteration, pop three values from the stack and push its value member. Otherwise, re-raise STACK[-1].

Added in version 3.12.

기타 옵코드

SET_ADD(i)

Implements:

item = STACK.pop()
set.add(STACK[-i], item)

Used to implement set comprehensions.

LIST_APPEND(i)

Implements:

item = STACK.pop()
list.append(STACK[-i], item)

Used to implement list comprehensions.

MAP_ADD(i)

Implements:

value = STACK.pop()
key = STACK.pop()
dict.__setitem__(STACK[-i], key, value)

Used to implement dict comprehensions.

Added in version 3.1.

버전 3.8에서 변경: Map value is STACK[-1] and map key is STACK[-2]. Before, those were reversed.

모든 SET_ADD, LIST_APPEND 및 MAP_ADD 명령어에 대해, 추가된 값이나 키/값 쌍이 팝 되지만, 컨테이너 객체는 스택에 남아 있어서 루프의 추가 이터레이션에 사용할 수 있습니다.

RETURN_VALUE

Returns with STACK[-1] to the caller of the function.

YIELD_VALUE

Yields STACK.pop() from a generator.

버전 3.11에서 변경: oparg set to be the stack depth.

버전 3.12에서 변경: oparg set to be the exception block depth, for efficient closing of generators.

버전 3.13에서 변경: oparg is 1 if this instruction is part of a yield-from or await, and 0 otherwise.

SETUP_ANNOTATIONS

locals()에 __annotations__가 정의되어 있는지 확인합니다, 그렇지 않으면 비어있는 dict로 설정됩니다. 이 옵코드는 클래스나 모듈 본문에 변수 어노테이션이 정적으로 포함될 때만 생성됩니다.

Added in version 3.6.

POP_EXCEPT

Pops a value from the stack, which is used to restore the exception state.

버전 3.11에서 변경: Exception representation on the stack now consist of one, not three, items.

RERAISE

Re-raises the exception currently on top of the stack. If oparg is non-zero, pops an additional value from the stack which is used to set f_lasti of the current frame.

Added in version 3.9.

버전 3.11에서 변경: Exception representation on the stack now consist of one, not three, items.

PUSH_EXC_INFO

Pops a value from the stack. Pushes the current exception to the top of the stack. Pushes the value originally popped back to the stack. Used in exception handlers.

Added in version 3.11.

CHECK_EXC_MATCH

Performs exception matching for except. Tests whether the STACK[-2] is an exception matching STACK[-1]. Pops STACK[-1] and pushes the boolean result of the test.

Added in version 3.11.

CHECK_EG_MATCH

Performs exception matching for except*. Applies split(STACK[-1]) on the exception group representing STACK[-2].

In case of a match, pops two items from the stack and pushes the non-matching subgroup (None in case of full match) followed by the matching subgroup. When there is no match, pops one item (the match type) and pushes None.

Added in version 3.11.

WITH_EXCEPT_START

Calls the function in position 4 on the stack with arguments (type, val, tb) representing the exception at the top of the stack. Used to implement the call context_manager.__exit__(*exc_info()) when an exception has occurred in a with statement.

Added in version 3.9.

버전 3.11에서 변경: The __exit__ function is in position 4 of the stack rather than 7. Exception representation on the stack now consist of one, not three, items.

LOAD_COMMON_CONSTANT

Pushes a common constant onto the stack. The interpreter contains a hardcoded list of constants supported by this instruction. Used by the assert statement to load AssertionError.

Added in version 3.14.

LOAD_BUILD_CLASS

Pushes builtins.__build_class__() onto the stack. It is later called to construct a class.

GET_LEN

Perform STACK.append(len(STACK[-1])). Used in match statements where comparison with structure of pattern is needed.

Added in version 3.10.

MATCH_MAPPING

If STACK[-1] is an instance of collections.abc.Mapping (or, more technically: if it has the Py_TPFLAGS_MAPPING flag set in its tp_flags), push True onto the stack. Otherwise, push False.

Added in version 3.10.

MATCH_SEQUENCE

If STACK[-1] is an instance of collections.abc.Sequence and is not an instance of str/bytes/bytearray (or, more technically: if it has the Py_TPFLAGS_SEQUENCE flag set in its tp_flags), push True onto the stack. Otherwise, push False.

Added in version 3.10.

MATCH_KEYS

STACK[-1] is a tuple of mapping keys, and STACK[-2] is the match subject. If STACK[-2] contains all of the keys in STACK[-1], push a tuple containing the corresponding values. Otherwise, push None.

Added in version 3.10.

버전 3.11에서 변경: Previously, this instruction also pushed a boolean value indicating success (True) or failure (False).

STORE_NAME(namei)

Implements name = STACK.pop(). namei is the index of name in the attribute co_names of the code object. The compiler tries to use STORE_FAST or STORE_GLOBAL if possible.

DELETE_NAME(namei)

Implements del name, where namei is the index into co_names attribute of the code object.

UNPACK_SEQUENCE(count)

Unpacks STACK[-1] into count individual values, which are put onto the stack right-to-left. Require there to be exactly count values.:

assert(len(STACK[-1]) == count)
STACK.extend(STACK.pop()[:-count-1:-1])

UNPACK_EX(counts)

Implements assignment with a starred target: Unpacks an iterable in STACK[-1] into individual values, where the total number of values can be smaller than the number of items in the iterable: one of the new values will be a list of all leftover items.

The number of values before and after the list value is limited to 255.

The number of values before the list value is encoded in the argument of the opcode. The number of values after the list if any is encoded using an EXTENDED_ARG. As a consequence, the argument can be seen as a two bytes values where the low byte of counts is the number of values before the list value, the high byte of counts the number of values after it.

The extracted values are put onto the stack right-to-left, i.e. a, *b, c = d will be stored after execution as STACK.extend((a, b, c)).

STORE_ATTR(namei)

Implements:

obj = STACK.pop()
value = STACK.pop()
obj.name = value

where namei is the index of name in co_names of the code object.

DELETE_ATTR(namei)

Implements:

obj = STACK.pop()
del obj.name

where namei is the index of name into co_names of the code object.

STORE_GLOBAL(namei)

STORE_NAME처럼 작동하지만, 이름을 전역으로 저장합니다.

DELETE_GLOBAL(namei)

DELETE_NAME처럼 작동하지만, 전역 이름을 삭제합니다.

LOAD_CONST(consti)

co_consts[consti]를 스택으로 푸시합니다.

LOAD_SMALL_INT(i)

Pushes the integer i onto the stack. i must be in range(256)

Added in version 3.14.

LOAD_CONST_IMMORTAL(consti)

Pushes co_consts[consti] onto the stack. Can be used when the constant value is known to be immortal.

Added in version 3.14.

LOAD_NAME(namei)

Pushes the value associated with co_names[namei] onto the stack. The name is looked up within the locals, then the globals, then the builtins.

LOAD_LOCALS

Pushes a reference to the locals dictionary onto the stack. This is used to prepare namespace dictionaries for LOAD_FROM_DICT_OR_DEREF and LOAD_FROM_DICT_OR_GLOBALS.

Added in version 3.12.

LOAD_FROM_DICT_OR_GLOBALS(i)

Pops a mapping off the stack and looks up the value for co_names[namei]. If the name is not found there, looks it up in the globals and then the builtins, similar to LOAD_GLOBAL. This is used for loading global variables in annotation scopes within class bodies.

Added in version 3.12.

BUILD_TUPLE(count)

Creates a tuple consuming count items from the stack, and pushes the resulting tuple onto the stack:

if count == 0:
    value = ()
else:
    value = tuple(STACK[-count:])
    STACK = STACK[:-count]

STACK.append(value)

BUILD_LIST(count)

BUILD_TUPLE처럼 작동하지만, 리스트를 만듭니다.

BUILD_SET(count)

BUILD_TUPLE처럼 작동하지만, 집합을 만듭니다.

BUILD_MAP(count)

Pushes a new dictionary object onto the stack. Pops 2 * count items so that the dictionary holds count entries: {..., STACK[-4]: STACK[-3], STACK[-2]: STACK[-1]}.

버전 3.5에서 변경: 딕셔너리는 count 항목을 갖도록 미리 크기가 조정된 빈 딕셔너리를 만드는 대신 스택 항목에서 만들어집니다.

BUILD_STRING(count)

스택에서 count 문자열을 이어붙이고 결과 문자열을 스택으로 푸시합니다.

Added in version 3.6.

LIST_EXTEND(i)

Implements:

seq = STACK.pop()
list.extend(STACK[-i], seq)

Used to build lists.

Added in version 3.9.

SET_UPDATE(i)

Implements:

seq = STACK.pop()
set.update(STACK[-i], seq)

Used to build sets.

Added in version 3.9.

DICT_UPDATE(i)

Implements:

map = STACK.pop()
dict.update(STACK[-i], map)

Used to build dicts.

Added in version 3.9.

DICT_MERGE(i)

DICT_UPDATE와 유사하지만, 중복 키에 대해 예외를 발생시킵니다.

Added in version 3.9.

LOAD_ATTR(namei)

If the low bit of namei is not set, this replaces STACK[-1] with getattr(STACK[-1], co_names[namei>>1]).

If the low bit of namei is set, this will attempt to load a method named co_names[namei>>1] from the STACK[-1] object. STACK[-1] is popped. This bytecode distinguishes two cases: if STACK[-1] has a method with the correct name, the bytecode pushes the unbound method and STACK[-1]. STACK[-1] will be used as the first argument (self) by CALL or CALL_KW when calling the unbound method. Otherwise, NULL and the object returned by the attribute lookup are pushed.

버전 3.12에서 변경: If the low bit of namei is set, then a NULL or self is pushed to the stack before the attribute or unbound method respectively.

LOAD_SUPER_ATTR(namei)

This opcode implements super(), both in its zero-argument and two-argument forms (e.g. super().method(), super().attr and super(cls, self).method(), super(cls, self).attr).

It pops three values from the stack (from top of stack down):

self: the first argument to the current method

cls: the class within which the current method was defined

the global super

With respect to its argument, it works similarly to LOAD_ATTR, except that namei is shifted left by 2 bits instead of 1.

The low bit of namei signals to attempt a method load, as with LOAD_ATTR, which results in pushing NULL and the loaded method. When it is unset a single value is pushed to the stack.

The second-low bit of namei, if set, means that this was a two-argument call to super() (unset means zero-argument).

Added in version 3.12.

COMPARE_OP(opname)

Performs a Boolean operation. The operation name can be found in cmp_op[opname >> 5]. If the fifth-lowest bit of opname is set (opname & 16), the result should be coerced to bool.

버전 3.13에서 변경: The fifth-lowest bit of the oparg now indicates a forced conversion to bool.

IS_OP(invert)

is 비교를 수행하거나, invert가 1이면 is not을 수행합니다.

Added in version 3.9.

CONTAINS_OP(invert)

in 비교를 수행하거나, invert가 1이면 not in을 수행합니다.

Added in version 3.9.

IMPORT_NAME(namei)

Imports the module co_names[namei]. STACK[-1] and STACK[-2] are popped and provide the fromlist and level arguments of __import__(). The module object is pushed onto the stack. The current namespace is not affected: for a proper import statement, a subsequent STORE_FAST instruction modifies the namespace.

IMPORT_FROM(namei)

Loads the attribute co_names[namei] from the module found in STACK[-1]. The resulting object is pushed onto the stack, to be subsequently stored by a STORE_FAST instruction.

JUMP_FORWARD(delta)

바이트 코드 카운터를 delta만큼 증가시킵니다.

JUMP_BACKWARD(delta)

Decrements bytecode counter by delta. Checks for interrupts.

Added in version 3.11.

JUMP_BACKWARD_NO_INTERRUPT(delta)

Decrements bytecode counter by delta. Does not check for interrupts.

Added in version 3.11.

POP_JUMP_IF_TRUE(delta)

If STACK[-1] is true, increments the bytecode counter by delta. STACK[-1] is popped.

버전 3.11에서 변경: The oparg is now a relative delta rather than an absolute target. This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

버전 3.12에서 변경: This is no longer a pseudo-instruction.

버전 3.13에서 변경: This instruction now requires an exact bool operand.

POP_JUMP_IF_FALSE(delta)

If STACK[-1] is false, increments the bytecode counter by delta. STACK[-1] is popped.

버전 3.11에서 변경: The oparg is now a relative delta rather than an absolute target. This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

버전 3.12에서 변경: This is no longer a pseudo-instruction.

버전 3.13에서 변경: This instruction now requires an exact bool operand.

POP_JUMP_IF_NOT_NONE(delta)

If STACK[-1] is not None, increments the bytecode counter by delta. STACK[-1] is popped.

This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

Added in version 3.11.

버전 3.12에서 변경: This is no longer a pseudo-instruction.

POP_JUMP_IF_NONE(delta)

If STACK[-1] is None, increments the bytecode counter by delta. STACK[-1] is popped.

This opcode is a pseudo-instruction, replaced in final bytecode by the directed versions (forward/backward).

Added in version 3.11.

버전 3.12에서 변경: This is no longer a pseudo-instruction.

FOR_ITER(delta)

STACK[-1] is an iterator. Call its __next__() method. If this yields a new value, push it on the stack (leaving the iterator below it). If the iterator indicates it is exhausted then the byte code counter is incremented by delta.

버전 3.12에서 변경: Up until 3.11 the iterator was popped when it was exhausted.

LOAD_GLOBAL(namei)

Loads the global named co_names[namei>>1] onto the stack.

버전 3.11에서 변경: If the low bit of namei is set, then a NULL is pushed to the stack before the global variable.

LOAD_FAST(var_num)

지역 co_varnames[var_num]에 대한 참조를 스택으로 푸시합니다.

버전 3.12에서 변경: This opcode is now only used in situations where the local variable is guaranteed to be initialized. It cannot raise UnboundLocalError.

LOAD_FAST_LOAD_FAST(var_nums)

Pushes references to co_varnames[var_nums >> 4] and co_varnames[var_nums & 15] onto the stack.

Added in version 3.13.

LOAD_FAST_CHECK(var_num)

Pushes a reference to the local co_varnames[var_num] onto the stack, raising an UnboundLocalError if the local variable has not been initialized.

Added in version 3.12.

LOAD_FAST_AND_CLEAR(var_num)

Pushes a reference to the local co_varnames[var_num] onto the stack (or pushes NULL onto the stack if the local variable has not been initialized) and sets co_varnames[var_num] to NULL.

Added in version 3.12.

STORE_FAST(var_num)

Stores STACK.pop() into the local co_varnames[var_num].

STORE_FAST_STORE_FAST(var_nums)

Stores STACK[-1] into co_varnames[var_nums >> 4] and STACK[-2] into co_varnames[var_nums & 15].

Added in version 3.13.

STORE_FAST_LOAD_FAST(var_nums)

Stores STACK.pop() into the local co_varnames[var_nums >> 4] and pushes a reference to the local co_varnames[var_nums & 15] onto the stack.

Added in version 3.13.

DELETE_FAST(var_num)

지역 co_varnames[var_num]을 삭제합니다.

MAKE_CELL(i)

Creates a new cell in slot i. If that slot is nonempty then that value is stored into the new cell.

Added in version 3.11.

LOAD_DEREF(i)

Loads the cell contained in slot i of the “fast locals” storage. Pushes a reference to the object the cell contains on the stack.

버전 3.11에서 변경: i is no longer offset by the length of co_varnames.

LOAD_FROM_DICT_OR_DEREF(i)

Pops a mapping off the stack and looks up the name associated with slot i of the “fast locals” storage in this mapping. If the name is not found there, loads it from the cell contained in slot i, similar to LOAD_DEREF. This is used for loading closure variables in class bodies (which previously used LOAD_CLASSDEREF) and in annotation scopes within class bodies.

Added in version 3.12.

STORE_DEREF(i)

Stores STACK.pop() into the cell contained in slot i of the “fast locals” storage.

버전 3.11에서 변경: i is no longer offset by the length of co_varnames.

DELETE_DEREF(i)

Empties the cell contained in slot i of the “fast locals” storage. Used by the del statement.

Added in version 3.2.

버전 3.11에서 변경: i is no longer offset by the length of co_varnames.

COPY_FREE_VARS(n)

Copies the n free (closure) variables from the closure into the frame. Removes the need for special code on the caller’s side when calling closures.

Added in version 3.11.

RAISE_VARARGS(argc)

argc의 값에 따라, raise 문의 3가지 형식 중 하나를 사용하여 예외를 발생시킵니다:

0: raise (이전 예외를 다시 발생시킵니다)

1: raise STACK[-1] (raise exception instance or type at STACK[-1])

2: raise STACK[-2] from STACK[-1] (raise exception instance or type at STACK[-2] with __cause__ set to STACK[-1])

CALL(argc)

Calls a callable object with the number of arguments specified by argc. On the stack are (in ascending order):

The callable

self or NULL

The remaining positional arguments

argc is the total of the positional arguments, excluding self.

CALL pops all arguments and the callable object off the stack, calls the callable object with those arguments, and pushes the return value returned by the callable object.

Added in version 3.11.

버전 3.13에서 변경: The callable now always appears at the same position on the stack.

버전 3.13에서 변경: Calls with keyword arguments are now handled by CALL_KW.

CALL_KW(argc)

Calls a callable object with the number of arguments specified by argc, including one or more named arguments. On the stack are (in ascending order):

The callable

self or NULL

The remaining positional arguments

The named arguments

A tuple of keyword argument names

argc is the total of the positional and named arguments, excluding self. The length of the tuple of keyword argument names is the number of named arguments.

CALL_KW pops all arguments, the keyword names, and the callable object off the stack, calls the callable object with those arguments, and pushes the return value returned by the callable object.

Added in version 3.13.

CALL_FUNCTION_EX(flags)

위치와 키워드 인자의 변수 집합으로 콜러블 객체를 호출합니다. flags의 최하위 비트가 설정되면, 스택의 맨 위에 추가 키워드 인자가 포함된 매핑 객체가 포함됩니다. 콜러블이 호출되기 전에, 매핑 객체와 이터러블 객체는 각각 “언팩” 되고 그 내용이 각각 키워드와 위치 인자로 전달됩니다. CALL_FUNCTION_EX는 모든 인자와 콜러블 객체를 스택에서 팝하고, 해당 인자로 콜러블 객체를 호출한 다음, 콜러블 객체가 반환한 반환 값을 푸시합니다.

Added in version 3.6.

PUSH_NULL

Pushes a NULL to the stack. Used in the call sequence to match the NULL pushed by LOAD_METHOD for non-method calls.

Added in version 3.11.

MAKE_FUNCTION

Pushes a new function object on the stack built from the code object at STACK[-1].

버전 3.10에서 변경: Flag value 0x04 is a tuple of strings instead of dictionary

버전 3.11에서 변경: Qualified name at STACK[-1] was removed.

버전 3.13에서 변경: Extra function attributes on the stack, signaled by oparg flags, were removed. They now use SET_FUNCTION_ATTRIBUTE.

SET_FUNCTION_ATTRIBUTE(flag)

Sets an attribute on a function object. Expects the function at STACK[-1] and the attribute value to set at STACK[-2]; consumes both and leaves the function at STACK[-1]. The flag determines which attribute to set:

0x01 위치 전용과 위치-키워드 매개 변수를 위한 기본값의 위치 순서 튜플

0x02 키워드 전용 매개 변수의 기본값 딕셔너리

0x04 a tuple of strings containing parameters’ annotations

0x08 자유 변수를 위한 셀을 포함하는 튜플, 클로저를 만듭니다

Added in version 3.13.

BUILD_SLICE(argc)

Pushes a slice object on the stack. argc must be 2 or 3. If it is 2, implements:

end = STACK.pop()
start = STACK.pop()
STACK.append(slice(start, end))

if it is 3, implements:

step = STACK.pop()
end = STACK.pop()
start = STACK.pop()
STACK.append(slice(start, end, step))

See the slice() built-in function for more information.

EXTENDED_ARG(ext)

너무 커서 기본 1바이트에 맞지 않는 인자를 가진 옵코드에 접두어로 붙입니다. ext는 인자에서 더 높은 비트로 작동하는 추가 바이트를 보유합니다. 각 옵코드마다, 최대 3개의 접두사 EXTENDED_ARG가 허용되며, 2바이트에서 4바이트 사이의 인자를 형성합니다.

CONVERT_VALUE(oparg)

Convert value to a string, depending on oparg:

value = STACK.pop()
result = func(value)
STACK.append(result)

oparg == 1: call str() on value

oparg == 2: call repr() on value

oparg == 3: call ascii() on value

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

FORMAT_SIMPLE

Formats the value on top of stack:

value = STACK.pop()
result = value.__format__("")
STACK.append(result)

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

FORMAT_WITH_SPEC

Formats the given value with the given format spec:

spec = STACK.pop()
value = STACK.pop()
result = value.__format__(spec)
STACK.append(result)

Used for implementing formatted literal strings (f-strings).

Added in version 3.13.

MATCH_CLASS(count)

STACK[-1] is a tuple of keyword attribute names, STACK[-2] is the class being matched against, and STACK[-3] is the match subject. count is the number of positional sub-patterns.

Pop STACK[-1], STACK[-2], and STACK[-3]. If STACK[-3] is an instance of STACK[-2] and has the positional and keyword attributes required by count and STACK[-1], push a tuple of extracted attributes. Otherwise, push None.

Added in version 3.10.

버전 3.11에서 변경: Previously, this instruction also pushed a boolean value indicating success (True) or failure (False).

RESUME(context)

A no-op. Performs internal tracing, debugging and optimization checks.

The context operand consists of two parts. The lowest two bits indicate where the RESUME occurs:

0 The start of a function, which is neither a generator, coroutine nor an async generator

1 After a yield expression

2 After a yield from expression

3 After an await expression

The next bit is 1 if the RESUME is at except-depth 1, and 0 otherwise.

Added in version 3.11.

버전 3.13에서 변경: The oparg value changed to include information about except-depth

RETURN_GENERATOR

Create a generator, coroutine, or async generator from the current frame. Used as first opcode of in code object for the above mentioned callables. Clear the current frame and return the newly created generator.

Added in version 3.11.

SEND(delta)

Equivalent to STACK[-1] = STACK[-2].send(STACK[-1]). Used in yield from and await statements.

If the call raises StopIteration, pop the top value from the stack, push the exception’s value attribute, and increment the bytecode counter by delta.

Added in version 3.11.

HAVE_ARGUMENT

This is not really an opcode. It identifies the dividing line between opcodes in the range [0,255] which don’t use their argument and those that do (< HAVE_ARGUMENT and >= HAVE_ARGUMENT, respectively).

If your application uses pseudo instructions or specialized instructions, use the hasarg collection instead.

버전 3.6에서 변경: 이제 모든 명령어에는 인자가 있지만, < HAVE_ARGUMENT인 옵코드는 이를 무시합니다. 이전에는, >= HAVE_ARGUMENT인 옵코드에만 인자가 있었습니다.

버전 3.12에서 변경: Pseudo instructions were added to the dis module, and for them it is not true that comparison with HAVE_ARGUMENT indicates whether they use their arg.

버전 3.13부터 폐지됨: Use hasarg instead.

CALL_INTRINSIC_1

Calls an intrinsic function with one argument. Passes STACK[-1] as the argument and sets STACK[-1] to the result. Used to implement functionality that is not performance critical.

The operand determines which intrinsic function is called:

Operand

Description

INTRINSIC_1_INVALID

Not valid

INTRINSIC_PRINT

Prints the argument to standard out. Used in the REPL.

INTRINSIC_IMPORT_STAR

Performs import * for the named module.

INTRINSIC_STOPITERATION_ERROR

Extracts the return value from a StopIteration exception.

INTRINSIC_ASYNC_GEN_WRAP

Wraps an async generator value

INTRINSIC_UNARY_POSITIVE

Performs the unary + operation

INTRINSIC_LIST_TO_TUPLE

Converts a list to a tuple

INTRINSIC_TYPEVAR

Creates a typing.TypeVar

INTRINSIC_PARAMSPEC

Creates a typing.ParamSpec

INTRINSIC_TYPEVARTUPLE

Creates a typing.TypeVarTuple

INTRINSIC_SUBSCRIPT_GENERIC

Returns typing.Generic subscripted with the argument

INTRINSIC_TYPEALIAS

Creates a typing.TypeAliasType; used in the type statement. The argument is a tuple of the type alias’s name, type parameters, and value.

Added in version 3.12.

CALL_INTRINSIC_2

Calls an intrinsic function with two arguments. Used to implement functionality that is not performance critical:

arg2 = STACK.pop()
arg1 = STACK.pop()
result = intrinsic2(arg1, arg2)
STACK.append(result)

The operand determines which intrinsic function is called:

Operand

Description

INTRINSIC_2_INVALID

Not valid

INTRINSIC_PREP_RERAISE_STAR

Calculates the ExceptionGroup to raise from a try-except*.

INTRINSIC_TYPEVAR_WITH_BOUND

Creates a typing.TypeVar with a bound.

INTRINSIC_TYPEVAR_WITH_CONSTRAINTS

Creates a typing.TypeVar with constraints.

INTRINSIC_SET_FUNCTION_TYPE_PARAMS

Sets the __type_params__ attribute of a function.

Added in version 3.12.

LOAD_SPECIAL

Performs special method lookup on STACK[-1]. If type(STACK[-1]).__xxx__ is a method, leave type(STACK[-1]).__xxx__; STACK[-1] on the stack. If type(STACK[-1]).__xxx__ is not a method, leave STACK[-1].__xxx__; NULL on the stack.

Added in version 3.14.

Pseudo-instructions

These opcodes do not appear in Python bytecode. They are used by the compiler but are replaced by real opcodes or removed before bytecode is generated.

SETUP_FINALLY(target)

Set up an exception handler for the following code block. If an exception occurs, the value stack level is restored to its current state and control is transferred to the exception handler at target.

SETUP_CLEANUP(target)

Like SETUP_FINALLY, but in case of an exception also pushes the last instruction (lasti) to the stack so that RERAISE can restore it. If an exception occurs, the value stack level and the last instruction on the frame are restored to their current state, and control is transferred to the exception handler at target.

SETUP_WITH(target)

Like SETUP_CLEANUP, but in case of an exception one more item is popped from the stack before control is transferred to the exception handler at target.

This variant is used in with and async with constructs, which push the return value of the context manager’s __enter__() or __aenter__() to the stack.

POP_BLOCK

Marks the end of the code block associated with the last SETUP_FINALLY, SETUP_CLEANUP or SETUP_WITH.

JUMP

JUMP_NO_INTERRUPT

Undirected relative jump instructions which are replaced by their directed (forward/backward) counterparts by the assembler.

JUMP_IF_TRUE

JUMP_IF_FALSE

Conditional jumps which do not impact the stack. Replaced by the sequence COPY 1, TO_BOOL, POP_JUMP_IF_TRUE/FALSE.

LOAD_CLOSURE(i)

Pushes a reference to the cell contained in slot i of the “fast locals” storage.

Note that LOAD_CLOSURE is replaced with LOAD_FAST in the assembler.

버전 3.13에서 변경: This opcode is now a pseudo-instruction.

LOAD_METHOD

Optimized unbound method lookup. Emitted as a LOAD_ATTR opcode with a flag set in the arg.

옵코드 모음

이 모음은 바이트 코드 명령어의 자동 검사를 위해 제공됩니다:

버전 3.12에서 변경: The collections now contain pseudo instructions and instrumented instructions as well. These are opcodes with values >= MIN_PSEUDO_OPCODE and >= MIN_INSTRUMENTED_OPCODE.

dis.opname

연산 이름의 시퀀스, 바이트 코드를 사용하여 인덱싱할 수 있습니다.

dis.opmap

연산 이름을 바이트 코드로 매핑하는 딕셔너리.

dis.cmp_op

모든 비교 연산 이름의 시퀀스.

dis.hasarg

Sequence of bytecodes that use their argument.

Added in version 3.12.

dis.hasconst

상수에 액세스하는 바이트 코드의 시퀀스.

dis.hasfree

Sequence of bytecodes that access a free (closure) variable. ‘free’ in this context refers to names in the current scope that are referenced by inner scopes or names in outer scopes that are referenced from this scope. It does not include references to global or builtin scopes.

dis.hasname

어트리뷰트를 이름으로 액세스하는 바이트 코드의 시퀀스.

dis.hasjump

Sequence of bytecodes that have a jump target. All jumps are relative.

Added in version 3.13.

dis.haslocal

지역 변수에 액세스하는 바이트 코드의 시퀀스.

dis.hascompare

불리언 연산의 바이트 코드의 시퀀스.

dis.hasexc

Sequence of bytecodes that set an exception handler.

Added in version 3.12.

dis.hasjrel

상대 점프 대상이 있는 바이트 코드의 시퀀스.

버전 3.13부터 폐지됨: All jumps are now relative. Use hasjump.

dis.hasjabs

절대 점프 대상이 있는 바이트 코드의 시퀀스.

버전 3.13부터 폐지됨: All jumps are now relative. This list is empty.

pickletools — Tools for pickle developers

소스 코드: Lib/pickletools.py [https://github.com/python/cpython/tree/main/Lib/pickletools.py]

이 모듈은 pickle 모듈의 깊은 세부 사항과 관련된 다양한 상수, 구현에 대한 긴 주석, 그리고 피클 된 데이터를 분석하기 위한 몇 가지 유용한 함수를 포함합니다. 이 모듈의 내용은 pickle에서 작업하는 파이썬 코어 개발자에게 유용합니다; 아마도 pickle 모듈의 일반 사용자는 pickletools 모듈을 적절한 용도를 찾지 못할 것입니다.

명령 줄 사용법

Added in version 3.2.

명령 줄에서 호출될 때, python -m pickletools는 하나 이상의 피클 파일의 내용을 역 어셈블합니다. 피클 형식의 세부 사항이 아닌 피클에 저장된 파이썬 객체를 보려면, 대신 -m pickle을 사용하는 것이 좋습니다. 그러나, 검사하려는 피클 파일이 신뢰할 수 없는 소스에서 왔을 때, 피클 바이트 코드를 실행하지 않으므로 -m pickletools가 더 안전한 옵션입니다.

예를 들어, 튜플 (1, 2)가 파일 x.pickle에 피클 된 경우:

$ python -m pickle x.pickle
(1, 2)

$ python -m pickletools x.pickle
    0: \x80 PROTO      3
    2: K    BININT1    1
    4: K    BININT1    2
    6: \x86 TUPLE2
    7: q    BINPUT     0
    9: .    STOP
highest protocol among opcodes = 2

명령 줄 옵션

-a, --annotate

각 줄에 짧은 opcode 설명으로 주석을 답니다.

-o, --output=<file>

출력이 기록되어야 하는 파일의 이름.

-l, --indentlevel=<num>

새 MARK 수준을 들여쓰기하는 공백의 수.

-m, --memo

여러 객체가 역 어셈블될 때, 역 어셈블리 간에 메모를 보존합니다.

-p, --preamble=<preamble>

하나 이상의 피클 파일이 지정될 때, 각 역 어셈블리 전에 주어진 프리앰블을 인쇄합니다.

프로그래밍 인터페이스

pickletools.dis(pickle, out=None, memo=None, indentlevel=4, annotate=0)

피클의 기호적인 역 어셈블리를 기본값이 sys.stdout인 파일류 객체 out으로 출력합니다. pickle는 문자열이나 파일류 객체가 될 수 있습니다. memo는 피클의 메모로 사용될 파이썬 딕셔너리일 수 있습니다; 같은 피클러로 만들어진 여러 피클에 걸쳐 역 어셈블리를 수행하는 데 사용할 수 있습니다. 스트림의 MARK 옵코드로 표시된 연속 수준은 indentlevel개의 스페이스로 들여쓰기 됩니다. 0이 아닌 값이 annotate에 주어지면, 출력의 각 옵코드에 짧은 설명이 주석으로 표시됩니다. annotate 값은 주석을 시작해야 하는 열의 힌트로 사용됩니다.

버전 3.2에서 변경: Added the annotate parameter.

pickletools.genops(pickle)

피클의 모든 옵코드에 대해 (opcode, arg, pos) 트리플을 반환하는 이터레이터를 제공합니다. opcode는 OpcodeInfo 클래스의 인스턴스입니다; arg는 옵코드 인자의 파이썬 객체로 디코딩된 값입니다; pos는 이 옵코드의 위치입니다. pickle은 문자열이나 파일류 객체가 될 수 있습니다.

pickletools.optimize(picklestring)

사용되지 않는 PUT 옵코드를 제거한 후 새로운 동등한 피클 문자열을 반환합니다. 최적화된 피클은 더 짧고, 전송 시간이 덜 걸리며, 저장 공간이 덜 필요하고, 역 피클이 더 효율적입니다.

MS 윈도우 특정 서비스

이 장에서는 MS 윈도우 플랫폼에서만 사용 가능한 모듈에 관해 설명합니다.

msvcrt — Useful routines from the MS VC++ runtime

파일 연산

locking()

LK_LOCK

LK_RLCK

LK_NBLCK

LK_NBRLCK

LK_UNLCK

setmode()

open_osfhandle()

get_osfhandle()

콘솔 I/O

kbhit()

getch()

getwch()

getche()

getwche()

putch()

putwch()

ungetch()

ungetwch()

기타 함수

heapmin()

set_error_mode()

OUT_TO_DEFAULT

OUT_TO_STDERR

OUT_TO_MSGBOX

REPORT_ERRMODE

CrtSetReportMode()

CrtSetReportFile()

CRT_WARN

CRT_ERROR

CRT_ASSERT

CRTDBG_MODE_DEBUG

CRTDBG_MODE_FILE

CRTDBG_MODE_WNDW

CRTDBG_REPORT_MODE

CRT_ASSEMBLY_VERSION

VC_ASSEMBLY_PUBLICKEYTOKEN

LIBRARIES_ASSEMBLY_NAME_PREFIX

winreg — Windows registry access

함수

CloseKey()

ConnectRegistry()

CreateKey()

CreateKeyEx()

DeleteKey()

DeleteKeyEx()

DeleteValue()

EnumKey()

EnumValue()

ExpandEnvironmentStrings()

FlushKey()

LoadKey()

OpenKey()

OpenKeyEx()

QueryInfoKey()

QueryValue()

QueryValueEx()

SaveKey()

SetValue()

SetValueEx()

DisableReflectionKey()

EnableReflectionKey()

QueryReflectionKey()

상수

HKEY_* 상수

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER

HKEY_LOCAL_MACHINE

HKEY_USERS

HKEY_PERFORMANCE_DATA

HKEY_CURRENT_CONFIG

HKEY_DYN_DATA

액세스 권한

KEY_ALL_ACCESS

KEY_WRITE

KEY_READ

KEY_EXECUTE

KEY_QUERY_VALUE

KEY_SET_VALUE

KEY_CREATE_SUB_KEY

KEY_ENUMERATE_SUB_KEYS

KEY_NOTIFY

KEY_CREATE_LINK

64비트 특정

KEY_WOW64_64KEY

KEY_WOW64_32KEY

값 형

REG_BINARY

REG_DWORD

REG_DWORD_LITTLE_ENDIAN

REG_DWORD_BIG_ENDIAN

REG_EXPAND_SZ

REG_LINK

REG_MULTI_SZ

REG_NONE

REG_QWORD

REG_QWORD_LITTLE_ENDIAN

REG_RESOURCE_LIST

REG_FULL_RESOURCE_DESCRIPTOR

REG_RESOURCE_REQUIREMENTS_LIST

REG_SZ

레지스트리 핸들 객체

Close()

Detach()

__enter__()

__exit__()

winsound — Sound-playing interface for Windows

Beep()

PlaySound()

MessageBeep()

SND_FILENAME

SND_ALIAS

SND_LOOP

SND_MEMORY

SND_PURGE

SND_ASYNC

SND_NODEFAULT

SND_NOSTOP

SND_NOWAIT

MB_ICONASTERISK

MB_ICONEXCLAMATION

MB_ICONHAND

MB_ICONQUESTION

MB_OK

msvcrt — Useful routines from the MS VC++ runtime

These functions provide access to some useful capabilities on Windows platforms. Some higher-level modules use these functions to build the Windows implementations of their services. For example, the getpass module uses this in the implementation of the getpass() function.

이 함수에 대한 자세한 설명은 플랫폼 API 설명서에서 찾을 수 있습니다.

이 모듈은 콘솔 I/O api의 일반과 광폭(wide) 문자 변형을 모두 구현합니다. 일반 API는 ASCII 문자만 다루며 국제화된 응용 프로그램에서는 제한적으로 사용됩니다. 가능하면 광폭 문자 API를 사용해야 합니다.

버전 3.3에서 변경: 이 모듈의 연산은 이제 IOError를 발생시키던 곳에서 OSError를 발생시킵니다.

파일 연산

msvcrt.locking(fd, mode, nbytes)

Lock part of a file based on file descriptor fd from the C runtime. Raises OSError on failure. The locked region of the file extends from the current file position for nbytes bytes, and may continue beyond the end of the file. mode must be one of the LK_* constants listed below. Multiple regions in a file may be locked at the same time, but may not overlap. Adjacent regions are not merged; they must be unlocked individually.

인자 fd, mode, nbytes로 감사 이벤트 msvcrt.locking을 발생시킵니다.

msvcrt.LK_LOCK

msvcrt.LK_RLCK

Locks the specified bytes. If the bytes cannot be locked, the program immediately tries again after 1 second. If, after 10 attempts, the bytes cannot be locked, OSError is raised.

msvcrt.LK_NBLCK

msvcrt.LK_NBRLCK

지정된 바이트를 잠급니다. 바이트를 잠글 수 없으면, OSError가 발생합니다.

msvcrt.LK_UNLCK

이전에 잠겨 있어야 하는 지정된 바이트의 잠금을 해제합니다.

msvcrt.setmode(fd, flags)

파일 기술자 fd의 줄 종료 변환 모드를 설정합니다. 텍스트 모드로 설정하려면, flags가 os.O_TEXT 여야 합니다; 바이너리는, os.O_BINARY 여야 합니다.

msvcrt.open_osfhandle(handle, flags)

Create a C runtime file descriptor from the file handle handle. The flags parameter should be a bitwise OR of os.O_APPEND, os.O_RDONLY, os.O_TEXT and os.O_NOINHERIT. The returned file descriptor may be used as a parameter to os.fdopen() to create a file object.

The file descriptor is inheritable by default. Pass os.O_NOINHERIT flag to make it non inheritable.

인자 handle, flags로 감사 이벤트 msvcrt.open_osfhandle을 발생시킵니다.

msvcrt.get_osfhandle(fd)

Return the file handle for the file descriptor fd. Raises OSError if fd is not recognized.

인자 fd로 감사 이벤트 msvcrt.get_osfhandle을 발생시킵니다.

콘솔 I/O

msvcrt.kbhit()

Returns a nonzero value if a keypress is waiting to be read. Otherwise, return 0.

msvcrt.getch()

Read a keypress and return the resulting character as a byte string. Nothing is echoed to the console. This call will block if a keypress is not already available, but will not wait for Enter to be pressed. If the pressed key was a special function key, this will return '\000' or '\xe0'; the next call will return the keycode. The Control-C keypress cannot be read with this function.

msvcrt.getwch()

유니코드 값을 반환하는 getch()의 광폭 문자 변형.

msvcrt.getche()

Similar to getch(), but the keypress will be echoed if it represents a printable character.

msvcrt.getwche()

유니코드 값을 반환하는 getche()의 광폭 문자 변형.

msvcrt.putch(char)

버퍼링하지 않고 바이트열 char을 콘솔에 인쇄합니다.

msvcrt.putwch(unicode_char)

유니코드 값을 받아들이는 putch()의 광폭 문자 변형.

msvcrt.ungetch(char)

바이트열 char이 콘솔 버퍼로 “푸시백” 되도록 합니다; getch() 나 getche()가 읽는 다음 문자가 됩니다.

msvcrt.ungetwch(unicode_char)

유니코드 값을 받아들이는 ungetch()의 광폭 문자 변형.

기타 함수

msvcrt.heapmin()

Force the malloc() heap to clean itself up and return unused blocks to the operating system. On failure, this raises OSError.

msvcrt.set_error_mode(mode)

Changes the location where the C runtime writes an error message for an error that might end the program. mode must be one of the OUT_* constants listed below or REPORT_ERRMODE. Returns the old setting or -1 if an error occurs. Only available in debug build of Python.

msvcrt.OUT_TO_DEFAULT

Error sink is determined by the app’s type. Only available in debug build of Python.

msvcrt.OUT_TO_STDERR

Error sink is a standard error. Only available in debug build of Python.

msvcrt.OUT_TO_MSGBOX

Error sink is a message box. Only available in debug build of Python.

msvcrt.REPORT_ERRMODE

Report the current error mode value. Only available in debug build of Python.

msvcrt.CrtSetReportMode(type, mode)

Specifies the destination or destinations for a specific report type generated by _CrtDbgReport() in the MS VC++ runtime. type must be one of the CRT_* constants listed below. mode must be one of the CRTDBG_* constants listed below. Only available in debug build of Python.

msvcrt.CrtSetReportFile(type, file)

After you use CrtSetReportMode() to specify CRTDBG_MODE_FILE, you can specify the file handle to receive the message text. type must be one of the CRT_* constants listed below. file should be the file handle your want specified. Only available in debug build of Python.

msvcrt.CRT_WARN

Warnings, messages, and information that doesn’t need immediate attention.

msvcrt.CRT_ERROR

Errors, unrecoverable problems, and issues that require immediate attention.

msvcrt.CRT_ASSERT

Assertion failures.

msvcrt.CRTDBG_MODE_DEBUG

Writes the message to the debugger’s output window.

msvcrt.CRTDBG_MODE_FILE

Writes the message to a user-supplied file handle. CrtSetReportFile() should be called to define the specific file or stream to use as the destination.

msvcrt.CRTDBG_MODE_WNDW

Creates a message box to display the message along with the Abort, Retry, and Ignore buttons.

msvcrt.CRTDBG_REPORT_MODE

Returns current mode for the specified type.

msvcrt.CRT_ASSEMBLY_VERSION

The CRT Assembly version, from the crtassem.h header file.

msvcrt.VC_ASSEMBLY_PUBLICKEYTOKEN

The VC Assembly public key token, from the crtassem.h header file.

msvcrt.LIBRARIES_ASSEMBLY_NAME_PREFIX

The Libraries Assembly name prefix, from the crtassem.h header file.

winreg — Windows registry access

이 함수들은 윈도우 레지스트리 API를 파이썬에 노출합니다. 프로그래머가 명시적으로 닫는 것을 무시하더라도 핸들이 올바르게 닫히도록 하기 위해, 레지스트리 핸들로 정수를 사용하는 대신 핸들 객체가 사용됩니다.

버전 3.3에서 변경: 이 모듈의 여러 함수는 WindowsError를 발생시켜왔는데, 이제는 OSError의 별칭입니다.

함수

이 모듈은 다음 함수를 제공합니다:

winreg.CloseKey(hkey)

이전에 열린 레지스트리 키를 닫습니다. hkey 인자는 이전에 열린 키를 지정합니다.

참고

이 메서드를 사용하여 (또는 hkey.Close()를 통해) hkey가 닫히지 않으면, hkey 객체가 파이썬에 의해 파괴될 때 닫힙니다.

winreg.ConnectRegistry(computer_name, key)

다른 컴퓨터에 있는 사전 정의된 레지스트리 핸들에 연결하고, 핸들 객체를 반환합니다.

computer_name은 r"\\computername" 형식의 원격 컴퓨터 이름입니다. None이면, 로컬 컴퓨터가 사용됩니다.

key는 연결할 사전 정의된 핸들입니다.

반환 값은 열린 키의 핸들입니다. 함수가 실패하면, OSError 예외가 발생합니다.

인자 computer_name, key로 감사 이벤트 winreg.ConnectRegistry를 발생시킵니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.CreateKey(key, sub_key)

지정된 키를 만들거나 열어, 핸들 객체를 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 이 메서드가 열거나 만드는 키의 이름을 지정하는 문자열입니다.

key가 사전 정의된 키 중 하나이면, sub_key는 None일 수 있습니다. 이 경우, 반환된 핸들은 함수에 전달된 것과 같은 키 핸들입니다.

키가 이미 존재하면, 이 함수는 기존 키를 엽니다.

반환 값은 열린 키의 핸들입니다. 함수가 실패하면, OSError 예외가 발생합니다.

인자 key, sub_key, access로 감사 이벤트 winreg.CreateKey를 발생시킵니다.

인자 key로 감사 이벤트 winreg.OpenKey/result를 발생시킵니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.CreateKeyEx(key, sub_key, reserved=0, access=KEY_WRITE)

지정된 키를 만들거나 열어, 핸들 객체를 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 이 메서드가 열거나 만드는 키의 이름을 지정하는 문자열입니다.

reserved는 예약된 정수이며, 0이어야 합니다. 기본값은 0입니다.

access는 키에 대한 원하는 보안 액세스를 기술하는 액세스 마스크를 지정하는 정수입니다. 기본값은 KEY_WRITE입니다. 허용되는 다른 값은 액세스 권한을 참조하십시오.

key가 사전 정의된 키 중 하나이면, sub_key는 None일 수 있습니다. 이 경우, 반환된 핸들은 함수에 전달된 것과 같은 키 핸들입니다.

키가 이미 존재하면, 이 함수는 기존 키를 엽니다.

반환 값은 열린 키의 핸들입니다. 함수가 실패하면, OSError 예외가 발생합니다.

인자 key, sub_key, access로 감사 이벤트 winreg.CreateKey를 발생시킵니다.

인자 key로 감사 이벤트 winreg.OpenKey/result를 발생시킵니다.

Added in version 3.2.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.DeleteKey(key, sub_key)

지정된 키를 삭제합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 key 매개 변수로 식별된 키의 서브 키여야 하는 문자열입니다. 이 값은 None이 아니어야 하며, 키에 서브 키가 없을 수 있습니다.

이 메서드는 서브 키가 있는 키를 삭제할 수 없습니다.

메서드가 성공하면, 모든 값을 포함하여 전체 키가 제거됩니다. 메서드가 실패하면, OSError 예외가 발생합니다.

인자 key, sub_key, access로 감사 이벤트 winreg.DeleteKey를 발생시킵니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.DeleteKeyEx(key, sub_key, access=KEY_WOW64_64KEY, reserved=0)

지정된 키를 삭제합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 key 매개 변수로 식별된 키의 서브 키여야 하는 문자열입니다. 이 값은 None이 아니어야 하며, 키에 서브 키가 없을 수 있습니다.

reserved는 예약된 정수이며, 0이어야 합니다. 기본값은 0입니다.

access is an integer that specifies an access mask that describes the desired security access for the key. Default is KEY_WOW64_64KEY. On 32-bit Windows, the WOW64 constants are ignored. See Access Rights for other allowed values.

이 메서드는 서브 키가 있는 키를 삭제할 수 없습니다.

메서드가 성공하면, 모든 값을 포함하여 전체 키가 제거됩니다. 메서드가 실패하면, OSError 예외가 발생합니다.

지원되지 않는 윈도우 버전에서는, NotImplementedError 가 발생합니다.

인자 key, sub_key, access로 감사 이벤트 winreg.DeleteKey를 발생시킵니다.

Added in version 3.2.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.DeleteValue(key, value)

레지스트리 키에서 명명된 값을 제거합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

value는 제거할 값을 식별하는 문자열입니다.

인자 key, value로 감사 이벤트 winreg.DeleteValue를 발생시킵니다.

winreg.EnumKey(key, index)

열린 레지스트리 키의 서브 키를 열거하고, 문자열을 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

index는 꺼낼 키의 인덱스를 식별하는 정수입니다.

이 함수는 호출될 때마다 하나의 서브 키 이름을 꺼냅니다. 일반적으로 더 이상 사용할 수 있는 값이 없음을 나타내는 OSError 예외가 발생할 때까지 반복적으로 호출됩니다.

인자 key, index로 감사 이벤트 winreg.EnumKey를 발생시킵니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.EnumValue(key, index)

열린 레지스트리 키의 값을 열거하고, 튜플을 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

index는 꺼낼 값의 인덱스를 식별하는 정수입니다.

이 함수는 호출될 때마다 하나의 서브 키 이름을 꺼냅니다. 일반적으로 더는 값이 없음을 표시하는 OSError 예외가 발생할 때까지 반복적으로 호출됩니다.

결과는 3개의 항목으로 구성된 튜플입니다:

인덱스

의미

0

값 이름을 식별하는 문자열

1

값 데이터를 담은 객체, 형이 하부 레지스트리 유형에 따라 달라집니다

2

값 데이터의 형을 식별하는 정수 (SetValueEx()에 대한 설명서에 있는 표를 참조하십시오)

인자 key, index로 감사 이벤트 winreg.EnumValue를 발생시킵니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.ExpandEnvironmentStrings(str)

REG_EXPAND_SZ와 같은 문자열에서 환경 변수 자리 표시자 %NAME%을 확장합니다:

>>> ExpandEnvironmentStrings('%windir%')
'C:\\Windows'

인자 str로 감사 이벤트 winreg.ExpandEnvironmentStrings를 발생시킵니다.

winreg.FlushKey(key)

키의 모든 어트리뷰트를 레지스트리에 씁니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

키를 변경하기 위해 FlushKey()를 호출할 필요는 없습니다. 레지스트리 변경은 지연 플러셔를 사용하여 레지스트리에 의해 디스크로 플러시 됩니다. 레지스트리 변경은 시스템 종료 시에도 디스크로 플러시 됩니다. CloseKey()와 달리, FlushKey() 메서드는 모든 데이터가 레지스트리에 기록될 때만 반환합니다. 응용 프로그램은 레지스트리 변경이 디스크에 있다는 절대적인 확신이 필요할 때만 FlushKey()를 호출해야 합니다.

참고

FlushKey() 호출이 필요한지 모른다면, 아마도 필요하지 않습니다.

winreg.LoadKey(key, sub_key, file_name)

지정된 키 아래에 서브 키를 만들고 지정된 파일에 있는 등록 정보를 그 서브 키에 저장합니다.

key는 ConnectRegistry()가 반환한 핸들이거나 상수 HKEY_USERS나 HKEY_LOCAL_MACHINE 중 하나입니다.

sub_key는 로드할 서브 키를 식별하는 문자열입니다.

file_name은 레지스트리 데이터를 로드할 파일의 이름입니다. 이 파일은 SaveKey() 함수로 만들어졌어야 합니다. FAT(file allocation table) 파일 시스템에서, 파일명은 확장자가 없을 수 있습니다.

A call to LoadKey() fails if the calling process does not have the SE_RESTORE_PRIVILEGE privilege. Note that privileges are different from permissions – see the RegLoadKey documentation [https://msdn.microsoft.com/en-us/library/ms724889%28v=VS.85%29.aspx] for more details.

key가 ConnectRegistry()가 반환한 핸들이면, file_name에 지정된 경로는 원격 컴퓨터에 상대적입니다.

인자 key, sub_key, file_name으로 감사 이벤트 winreg.LoadKey를 발생시킵니다.

winreg.OpenKey(key, sub_key, reserved=0, access=KEY_READ)

winreg.OpenKeyEx(key, sub_key, reserved=0, access=KEY_READ)

지정된 키를 열고, 핸들 객체를 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 열 서브 키를 식별하는 문자열입니다.

reserved는 예약된 정수이며, 0이어야 합니다. 기본값은 0입니다.

access는 키에 대한 원하는 보안 액세스를 기술하는 액세스 마스크를 지정하는 정수입니다. 기본값은 KEY_READ입니다. 허용되는 다른 값은 액세스 권한을 참조하십시오.

결과는 지정된 키에 대한 새로운 핸들입니다.

함수가 실패하면, OSError가 발생합니다.

인자 key, sub_key, access로 감사 이벤트 winreg.OpenKey를 발생시킵니다.

인자 key로 감사 이벤트 winreg.OpenKey/result를 발생시킵니다.

버전 3.2에서 변경: 명명된 인자 사용을 허용합니다.

버전 3.3에서 변경: 위를 참조하십시오.

winreg.QueryInfoKey(key)

키에 대한 정보를 튜플로 반환합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

결과는 3개의 항목으로 구성된 튜플입니다:

인덱스

의미

0

이 키가 가진 서브 키의 수를 제공하는 정수.

1

이 키가 가진 값의 수를 제공하는 정수.

2

키가 마지막으로 수정된 때(있다면)를 1601년 1월 1일 이후로 지난 100나노초로 제공하는 정수.

인자 key로 감사 이벤트 winreg.QueryInfoKey를 발생시킵니다.

winreg.QueryValue(key, sub_key)

키의 이름이 없는 값을 문자열로 가져옵니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 값이 연관된 서브 키의 이름을 담은 문자열입니다. 이 매개 변수가 None이거나 비어있으면, 함수는 key로 식별된 키에 대해 SetValue() 메서드로 설정된 값을 가져옵니다.

레지스트리의 값에는 이름, 형 및 데이터 구성 요소가 있습니다. 이 메서드는 NULL 이름을 가진 키의 첫 번째 값에 대한 데이터를 가져옵니다. 그러나 하부 API 호출은 형을 반환하지 않아서, 가능하다면 항상 QueryValueEx()를 사용하십시오.

인자 key, sub_key, value_name으로 감사 이벤트 winreg.QueryValue를 발생시킵니다.

winreg.QueryValueEx(key, value_name)

열린 레지스트리 키와 연관된 지정된 값 이름의 형과 데이터를 가져옵니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

value_name은 조회할 값을 나타내는 문자열입니다.

결과는 2개의 항목으로 구성된 튜플입니다:

인덱스

의미

0

레지스트리 항목의 값.

1

이 값에 대한 레지스트리 유형을 제공하는 정수 (SetValueEx()의 설명서에 있는 표를 참조하십시오)

인자 key, sub_key, value_name으로 감사 이벤트 winreg.QueryValue를 발생시킵니다.

winreg.SaveKey(key, file_name)

지정된 키와 그것의 모든 서브 키를 지정된 파일에 저장합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

file_name은 레지스트리 데이터를 저장할 파일 이름입니다. 이 파일은 이미 존재할 수 없습니다. 이 파일명에 확장자가 포함되어 있으면, LoadKey() 메서드로 FAT(file allocation table) 파일 시스템에서 사용할 수 없습니다.

If key represents a key on a remote computer, the path described by file_name is relative to the remote computer. The caller of this method must possess the SeBackupPrivilege security privilege. Note that privileges are different than permissions – see the Conflicts Between User Rights and Permissions documentation [https://msdn.microsoft.com/en-us/library/ms724878%28v=VS.85%29.aspx] for more details.

이 함수는 security_attributes로 NULL을 API로 전달합니다.

인자 key, file_name으로 감사 이벤트 winreg.SaveKey를 발생시킵니다.

winreg.SetValue(key, sub_key, type, value)

값을 지정된 키와 연관시킵니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

sub_key는 값이 연관된 서브 키의 이름을 지정하는 문자열입니다.

type은 데이터의 형을 지정하는 정수입니다. 현재 이것은 REG_SZ 여야 하는데, 문자열만 지원된다는 뜻입니다. 다른 데이터형을 지원하려면 SetValueEx() 함수를 사용하십시오.

value는 새 값을 지정하는 문자열입니다.

sub_key 매개 변수로 지정된 키가 존재하지 않으면, SetValue 함수가 이를 만듭니다.

값 길이는 사용 가능한 메모리에 따라 제한됩니다. 긴 값(2048바이트보다 긴)은 구성 레지스트리에 저장된 파일명을 가진 파일로 저장해야 합니다. 이렇게 하면 레지스트리가 효율적으로 수행하는 데 도움을 줍니다.

key 매개 변수로 식별된 키는 KEY_SET_VALUE 액세스로 열렸어야 합니다.

인자 key, sub_key, type, value로 감사 이벤트 winreg.SetValue를 발생시킵니다.

winreg.SetValueEx(key, value_name, reserved, type, value)

열린 레지스트리 키의 값 필드에 데이터를 저장합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

value_name은 값이 연관된 서브 키의 이름을 지정하는 문자열입니다.

reserved는 무엇이든 가능합니다 – 0이 항상 API로 전달됩니다.

type은 데이터의 형을 지정하는 정수입니다. 사용 가능한 형은 값 형을 참조하십시오.

value는 새 값을 지정하는 문자열입니다.

이 메서드는 지정된 키에 대한 추가 값과 형 정보를 설정할 수도 있습니다. key 매개 변수로 식별된 키는 KEY_SET_VALUE 액세스로 열렸어야 합니다.

키를 열려면, CreateKey()나 OpenKey() 메서드를 사용하십시오.

값 길이는 사용 가능한 메모리에 따라 제한됩니다. 긴 값(2048바이트보다 긴)은 구성 레지스트리에 저장된 파일명을 가진 파일로 저장해야 합니다. 이렇게 하면 레지스트리가 효율적으로 수행하는 데 도움을 줍니다.

인자 key, sub_key, type, value로 감사 이벤트 winreg.SetValue를 발생시킵니다.

winreg.DisableReflectionKey(key)

64비트 운영 체제에서 실행 중인 32비트 프로세스에 대한 레지스트리 리플렉션(reflection)을 비활성화합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

32비트 운영 체제에서 실행하면 일반적으로 NotImplementedError 가 발생합니다.

키가 리플렉션 목록에 없으면, 함수는 성공하지만 아무런 효과가 없습니다. 키에 대한 리플렉션을 비활성화해도 서브 키의 리플렉션에는 영향을 미치지 않습니다.

인자 key로 감사 이벤트 winreg.DisableReflectionKey를 발생시킵니다.

winreg.EnableReflectionKey(key)

지정된 비활성화 된 키에 대한 레지스트리 리플렉션(reflection)을 복원합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

32비트 운영 체제에서 실행하면 일반적으로 NotImplementedError 가 발생합니다.

키에 대한 리플렉션을 복원해도 서브 키의 리플렉션에 영향을 미치지 않습니다.

인자 key로 감사 이벤트 winreg.EnableReflectionKey를 발생시킵니다.

winreg.QueryReflectionKey(key)

지정된 키의 리플렉션(reflection) 상태를 판단합니다.

key는 이미 열린 키이거나, 사전 정의된 HKEY_* 상수 중 하나입니다.

리플렉션이 비활성화되었으면 True를 반환합니다.

32비트 운영 체제에서 실행하면 일반적으로 NotImplementedError 가 발생합니다.

인자 key로 감사 이벤트 winreg.QueryReflectionKey를 발생시킵니다.

상수

The following constants are defined for use in many winreg functions.

HKEY_* 상수

winreg.HKEY_CLASSES_ROOT

이 키에 종속된 레지스트리 항목은 문서의 형(또는 클래스)과 해당 형과 연관된 속성을 정의합니다. 셸과 COM 응용 프로그램은 이 키에 저장된 정보를 사용합니다.

winreg.HKEY_CURRENT_USER

이 키에 종속된 레지스트리 항목은 현재 사용자의 환경 설정(preferences)을 정의합니다. 이러한 환경 설정에는 환경 변수 설정, 프로그램 그룹, 색상, 프린터, 네트워크 연결 및 응용 프로그램 환경 설정에 대한 데이터가 포함됩니다.

winreg.HKEY_LOCAL_MACHINE

이 키에 종속된 레지스트리 항목은 버스 유형, 시스템 메모리 및 설치된 하드웨어와 소프트웨어에 대한 데이터를 포함하는 컴퓨터의 물리적 상태를 정의합니다.

winreg.HKEY_USERS

이 키에 종속된 레지스트리 항목은 로컬 컴퓨터의 새 사용자를 위한 기본 사용자 구성과 현재 사용자의 사용자 구성을 정의합니다.

winreg.HKEY_PERFORMANCE_DATA

이 키에 종속된 레지스트리 항목을 사용하면 성능 데이터에 액세스 할 수 있습니다. 데이터는 실제로 레지스트리에 저장되지 않습니다; 레지스트리 함수는 시스템이 소스에서 데이터를 수집하도록 합니다.

winreg.HKEY_CURRENT_CONFIG

로컬 컴퓨터 시스템의 현재 하드웨어 프로필에 대한 정보가 들어 있습니다.

winreg.HKEY_DYN_DATA

이 키는 98 이후의 윈도우 버전에서는 사용되지 않습니다.

액세스 권한

자세한 내용은 레지스트리 키 보안과 액세스 [https://msdn.microsoft.com/en-us/library/ms724878%28v=VS.85%29.aspx]를 참조하십시오.

winreg.KEY_ALL_ACCESS

STANDARD_RIGHTS_REQUIRED, KEY_QUERY_VALUE, KEY_SET_VALUE, KEY_CREATE_SUB_KEY, KEY_ENUMERATE_SUB_KEYS, KEY_NOTIFY 및 KEY_CREATE_LINK 액세스 권한을 결합합니다.

winreg.KEY_WRITE

STANDARD_RIGHTS_WRITE, KEY_SET_VALUE 및 KEY_CREATE_SUB_KEY 액세스 권한을 결합합니다.

winreg.KEY_READ

STANDARD_RIGHTS_READ, KEY_QUERY_VALUE, KEY_ENUMERATE_SUB_KEYS 및 KEY_NOTIFY 값을 결합합니다.

winreg.KEY_EXECUTE

KEY_READ와 동등합니다.

winreg.KEY_QUERY_VALUE

레지스트리 키의 값을 조회하는 데 필요합니다.

winreg.KEY_SET_VALUE

레지스트리 값을 생성, 삭제 또는 설정하는 데 필요합니다.

winreg.KEY_CREATE_SUB_KEY

레지스트리 키의 서브 키를 만드는 데 필요합니다.

winreg.KEY_ENUMERATE_SUB_KEYS

레지스트리 키의 서브 키를 열거하는 데 필요합니다.

winreg.KEY_NOTIFY

레지스트리 키나 레지스트리 키의 서브 키에 대한 변경 알림을 요청하는 데 필요합니다.

winreg.KEY_CREATE_LINK

시스템 사용을 위해 예약되어 있습니다.

64비트 특정

자세한 내용은 대체 레지스트리 뷰에 액세스하기 [https://msdn.microsoft.com/en-us/library/aa384129(v=VS.85).aspx]를 참조하십시오.

winreg.KEY_WOW64_64KEY

Indicates that an application on 64-bit Windows should operate on the 64-bit registry view. On 32-bit Windows, this constant is ignored.

winreg.KEY_WOW64_32KEY

Indicates that an application on 64-bit Windows should operate on the 32-bit registry view. On 32-bit Windows, this constant is ignored.

값 형

자세한 내용은 레지스트리 값 형 [https://msdn.microsoft.com/en-us/library/ms724884%28v=VS.85%29.aspx]을 참조하십시오.

winreg.REG_BINARY

모든 형태의 바이너리 데이터.

winreg.REG_DWORD

32비트 숫자.

winreg.REG_DWORD_LITTLE_ENDIAN

리틀 엔디안 형식의 32비트 숫자. REG_DWORD와 동등합니다.

winreg.REG_DWORD_BIG_ENDIAN

빅 엔디안 형식의 32비트 숫자.

winreg.REG_EXPAND_SZ

환경 변수(%PATH%)에 대한 참조를 포함하는 널 종료 문자열.

winreg.REG_LINK

유니코드 심볼릭 링크.

winreg.REG_MULTI_SZ

두 개의 널 문자로 끝나는 널 종료 문자열의 시퀀스. (파이썬은 이 종료를 자동으로 처리합니다.)

winreg.REG_NONE

정의된 값 형이 없습니다.

winreg.REG_QWORD

64비트 숫자.

Added in version 3.6.

winreg.REG_QWORD_LITTLE_ENDIAN

리틀 엔디안 형식의 64비트 숫자. REG_QWORD와 동등합니다.

Added in version 3.6.

winreg.REG_RESOURCE_LIST

장치 드라이버 리소스 목록.

winreg.REG_FULL_RESOURCE_DESCRIPTOR

하드웨어 설정.

winreg.REG_RESOURCE_REQUIREMENTS_LIST

하드웨어 리소스 목록.

winreg.REG_SZ

널 종료 문자열.

레지스트리 핸들 객체

이 객체는 윈도우 HKEY 객체를 감싸서, 객체가 파괴될 때 자동으로 닫습니다. 정리를 보장하기 위해, 객체의 Close() 메서드나 CloseKey() 함수를 호출할 수 있습니다.

이 모듈의 모든 레지스트리 함수는 이러한 객체 중 하나를 반환합니다.

핸들 객체를 받아들이는 이 모듈의 모든 레지스트리 함수는 정수도 받아들이지만, 핸들 객체의 사용을 권장합니다.

Handle objects provide semantics for __bool__() – thus

if handle:
    print("Yes")

는 핸들이 현재 유효하면 (닫혔거나 분리되지(detached) 않았으면) Yes를 인쇄합니다.

객체는 또한 비교 개념을 지원하므로, 핸들 객체가 모두 같은 하부 윈도우 핸들값을 참조하면 참으로 비교됩니다.

핸들 객체는 정수로 변환될 수 있으며 (예를 들어, 내장 int() 함수 사용해서), 이 경우 하부 윈도우 핸들값이 반환됩니다. Detach() 메서드를 사용하여 정수 핸들을 반환하고 핸들 객체에서 윈도우 핸들을 분리할 수도 있습니다.

PyHKEY.Close()

하부 윈도우 핸들을 닫습니다.

핸들이 이미 닫혀 있으면, 에러가 발생하지 않습니다.

PyHKEY.Detach()

핸들 객체에서 윈도우 핸들을 분리합니다.

결과는 핸들이 분리되기 전의 핸들 값을 담고 있는 정수입니다. 핸들이 이미 분리되었거나 닫혔으면 0이 반환됩니다.

이 함수를 호출한 후에는, 핸들이 효과적으로 무효가 되지만, 핸들이 닫히지는 않습니다. 하부 Win32 핸들이 핸들 객체의 수명을 넘어 존재해야 할 때 이 함수를 호출합니다.

인자 key로 감사 이벤트 winreg.PyHKEY.Detach를 발생시킵니다.

PyHKEY.__enter__()

PyHKEY.__exit__(*exc_info)

HKEY 객체는 __enter__()와 __exit__()를 구현하므로 with 문의 컨텍스트 프로토콜을 지원합니다:

with OpenKey(HKEY_LOCAL_MACHINE, "foo") as key:
    ...  # work with key

는 제어가 with 블록을 벗어날 때 key를 자동으로 닫습니다.

winsound — Sound-playing interface for Windows

winsound 모듈은 윈도우 플랫폼에서 제공하는 기본 소리 재생 장치에 대한 액세스를 제공합니다. 함수와 여러 상수를 포함합니다.

winsound.Beep(frequency, duration)

PC 스피커로 신호음을 울립니다. frequency 매개 변수는 소리의 주파수를 헤르츠 단위로 지정하며 37에서 32,767 범위에 있어야 합니다. duration 매개 변수는 소리의 지속 시간을 밀리 초로 지정합니다. 시스템이 스피커에서 신호음을 울리지 못하면, RuntimeError가 발생합니다.

winsound.PlaySound(sound, flags)

Call the underlying PlaySound() function from the Platform API. The sound parameter may be a filename, a system sound alias, audio data as a bytes-like object, or None. Its interpretation depends on the value of flags, which can be a bitwise ORed combination of the constants described below. If the sound parameter is None, any currently playing waveform sound is stopped. If the system indicates an error, RuntimeError is raised.

winsound.MessageBeep(type=MB_OK)

Call the underlying MessageBeep() function from the Platform API. This plays a sound as specified in the registry. The type argument specifies which sound to play; possible values are -1, MB_ICONASTERISK, MB_ICONEXCLAMATION, MB_ICONHAND, MB_ICONQUESTION, and MB_OK, all described below. The value -1 produces a “simple beep”; this is the final fallback if a sound cannot be played otherwise. If the system indicates an error, RuntimeError is raised.

winsound.SND_FILENAME

sound 매개 변수는 WAV 파일의 이름입니다. SND_ALIAS와 함께 사용하지 마십시오.

winsound.SND_ALIAS

sound 매개 변수는 레지스트리의 소리 연결 이름입니다. 레지스트리에 그러한 이름이 없으면, SND_NODEFAULT도 함께 지정하지 않는 한 시스템 기본 소리를 재생합니다. 기본 소리가 등록되어 있지 않으면, RuntimeError를 일으킵니다. SND_FILENAME과 함께 사용하지 마십시오.

모든 Win32 시스템은 적어도 다음을 지원합니다; 대부분 시스템은 더 많은 것을 지원합니다:

PlaySound() 이름

해당 제어판 소리 이름

'SystemAsterisk'

Asterisk

'SystemExclamation'

Exclamation

'SystemExit'

Exit Windows

'SystemHand'

Critical Stop

'SystemQuestion'

Question

예를 들면:

import winsound
# Play Windows exit sound.
winsound.PlaySound("SystemExit", winsound.SND_ALIAS)

# Probably play Windows default sound, if any is registered (because
# "*" probably isn't the registered name of any sound).
winsound.PlaySound("*", winsound.SND_ALIAS)

winsound.SND_LOOP

소리를 반복해서 재생합니다. 블로킹을 피하고자 SND_ASYNC 플래그도 사용해야 합니다. SND_MEMORY와 함께 사용할 수 없습니다.

winsound.SND_MEMORY

PlaySound()에 대한 sound 매개 변수는 바이트열류 객체의 WAV 파일의 메모리 이미지입니다.

참고

이 모듈은 메모리 이미지를 비동기적으로 재생하는 것을 지원하지 않으므로, 이 플래그와 SND_ASYNC의 조합은 RuntimeError를 발생시킵니다.

winsound.SND_PURGE

지정된 소리의 모든 인스턴스 재생을 중지합니다.

참고

이 플래그는 최신 윈도우 플랫폼에서 지원되지 않습니다.

winsound.SND_ASYNC

소리를 비동기적으로 재생할 수 있도록, 즉시 반환합니다.

winsound.SND_NODEFAULT

지정된 소리를 찾을 수 없을 때, 시스템 기본 소리를 재생하지 않습니다.

winsound.SND_NOSTOP

현재 재생 중인 소리를 중단하지 않습니다.

winsound.SND_NOWAIT

사운드 드라이버가 바쁘면 즉시 반환합니다.

참고

이 플래그는 최신 윈도우 플랫폼에서 지원되지 않습니다.

winsound.MB_ICONASTERISK

SystemDefault 소리를 재생합니다.

winsound.MB_ICONEXCLAMATION

SystemExclamation 소리를 재생합니다.

winsound.MB_ICONHAND

SystemHand 소리를 재생합니다.

winsound.MB_ICONQUESTION

SystemQuestion 소리를 재생합니다.

winsound.MB_OK

SystemDefault 소리를 재생합니다.

유닉스 특정 서비스

이 장에서 설명하는 모듈은 유닉스 운영 체제(혹은 때에 따라 일부 혹은 많은 변종)에 고유한 기능에 대한 인터페이스를 제공합니다. 다음은 개요입니다:

posix — The most common POSIX system calls

대용량 파일 지원

주목할만한 모듈 내용

environ

pwd — The password database

getpwuid()

getpwnam()

getpwall()

grp — The group database

getgrgid()

getgrnam()

getgrall()

termios — POSIX style tty control

tcgetattr()

tcsetattr()

TCSANOW

TCSADRAIN

TCSAFLUSH

tcsendbreak()

tcdrain()

tcflush()

tcflow()

tcgetwinsize()

tcsetwinsize()

예제

tty — Terminal control functions

cfmakeraw()

cfmakecbreak()

setraw()

setcbreak()

pty — Pseudo-terminal utilities

fork()

openpty()

spawn()

예제

fcntl — The fcntl and ioctl system calls

fcntl()

ioctl()

flock()

lockf()

LOCK_UN

LOCK_SH

LOCK_EX

LOCK_NB

resource — Resource usage information

error

자원 제한

RLIM_INFINITY

getrlimit()

setrlimit()

prlimit()

RLIMIT_CORE

RLIMIT_CPU

RLIMIT_FSIZE

RLIMIT_DATA

RLIMIT_STACK

RLIMIT_RSS

RLIMIT_NPROC

RLIMIT_NOFILE

RLIMIT_OFILE

RLIMIT_MEMLOCK

RLIMIT_VMEM

RLIMIT_AS

RLIMIT_MSGQUEUE

RLIMIT_NICE

RLIMIT_RTPRIO

RLIMIT_RTTIME

RLIMIT_SIGPENDING

RLIMIT_SBSIZE

RLIMIT_SWAP

RLIMIT_NPTS

RLIMIT_KQUEUES

자원 사용량

getrusage()

getpagesize()

RUSAGE_SELF

RUSAGE_CHILDREN

RUSAGE_BOTH

RUSAGE_THREAD

syslog — Unix syslog library routines

syslog()

openlog()

closelog()

setlogmask()

LOG_EMERG

LOG_ALERT

LOG_CRIT

LOG_ERR

LOG_WARNING

LOG_NOTICE

LOG_INFO

LOG_DEBUG

LOG_AUTH

LOG_AUTHPRIV

LOG_CRON

LOG_DAEMON

LOG_FTP

LOG_INSTALL

LOG_KERN

LOG_LAUNCHD

LOG_LPR

LOG_MAIL

LOG_NETINFO

LOG_NEWS

LOG_RAS

LOG_REMOTEAUTH

LOG_SYSLOG

LOG_USER

LOG_UUCP

LOG_LOCAL0

LOG_LOCAL1

LOG_LOCAL2

LOG_LOCAL3

LOG_LOCAL4

LOG_LOCAL5

LOG_LOCAL6

LOG_LOCAL7

LOG_PID

LOG_CONS

LOG_NDELAY

LOG_ODELAY

LOG_NOWAIT

LOG_PERROR

예제

간단한 예제

posix — The most common POSIX system calls

이 모듈은 C 표준과 POSIX 표준(얇게 위장한 유닉스 인터페이스)에 의해 표준화된 운영 체제 기능에 대한 액세스를 제공합니다.

Availability: Unix.

이 모듈을 직접 임포트 하지 마십시오. 대신, 이 인터페이스의 이식성 있는 버전을 제공하는 모듈 os를 임포트 하십시오. 유닉스에서, os 모듈은 posix 인터페이스의 상위집합을 제공합니다. 비 유닉스 운영 체제에서는 posix 모듈을 사용할 수 없지만, os 인터페이스를 통해 항상 부분집합을 사용할 수 있습니다. 일단 os를 임포트하면, posix 대신 사용해도 성능 저하가 없습니다. 또한, os는 os.environ의 항목이 변경될 때 자동으로 putenv()를 호출하는 등의 몇 가지 추가 기능을 제공합니다.

에러는 예외로 보고됩니다; 보통 예외는 형 에러로 인한 것입니다만, 시스템 호출 때문에 보고되는 에러는 OSError를 발생시킵니다.

대용량 파일 지원

Several operating systems (including AIX and Solaris) provide support for files that are larger than 2 GiB from a C programming model where int and long are 32-bit values. This is typically accomplished by defining the relevant size and offset types as 64-bit values. Such files are sometimes referred to as large files.

Large file support is enabled in Python when the size of an off_t is larger than a long and the long long is at least as large as an off_t. It may be necessary to configure and compile Python with certain compiler flags to enable this mode. For example, with Solaris 2.6 and 2.7 you need to do something like:

CFLAGS="`getconf LFS_CFLAGS`" OPT="-g -O2 $CFLAGS" \
        ./configure

대용량 파일을 사용할 수 있는 리눅스 시스템에서, 이렇게 할 수 있습니다:

CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \
        ./configure

주목할만한 모듈 내용

os 모듈 설명서에서 설명된 많은 함수 외에도, posix는 다음 데이터 항목을 정의합니다:

posix.environ

인터프리터가 시작될 때 문자열 환경을 나타내는 딕셔너리. 키와 값은 유닉스에서는 바이트열이고 윈도우에서는 str입니다. 예를 들어, environ[b'HOME'](윈도우에서는 environ['HOME'])은 홈 디렉터리의 경로명이며, C의 getenv("HOME")와 동등합니다.

이 딕셔너리를 수정해도 execv(), popen() 또는 system()에 전달되는 문자열 환경에는 영향을 주지 않습니다; 환경을 변경해야 하는 경우 environ을 execve()로 전달하거나, system() 이나 popen()의 명령 문자열에 변수 대입과 export 문장을 추가하십시오.

버전 3.2에서 변경: 유닉스에서, 키와 값은 바이트열입니다.

참고

os 모듈은 수정 시 환경을 갱신하는 environ의 대체 구현을 제공합니다. os.environ를 갱신하면 이 딕셔너리를 쓸모없게 만드는 것에 유의하십시오. os 모듈 버전을 사용하는 것이 posix 모듈에 직접 액세스하는 것보다 권장됩니다.

pwd — The password database

이 모듈은 유닉스 사용자 계정과 암호 데이터베이스에 대한 액세스를 제공합니다. 모든 유닉스 버전에서 사용할 수 있습니다.

Availability: Unix, not WASI, not iOS.

암호 데이터베이스 항목은 passwd 구조체(아래의 어트리뷰트 필드, <pwd.h>를 보세요)의 멤버에 해당하는 어트리뷰트를 가진 튜플류 객체로 보고됩니다.:

인덱스

어트리뷰트

의미

0

pw_name

로그인 이름

1

pw_passwd

선택적 암호화된 암호

2

pw_uid

숫자 사용자 ID

3

pw_gid

숫자 그룹 ID

4

pw_gecos

사용자 이름이나 주석 필드

5

pw_dir

사용자 홈 디렉터리

6

pw_shell

사용자 명령 인터프리터

uid 및 gid 항목은 정수이고, 다른 모든 항목은 문자열입니다. 요청된 항목을 찾을 수 없으면 KeyError가 발생합니다.

참고

In traditional Unix the field pw_passwd usually contains a password encrypted with a DES derived algorithm. However most modern unices use a so-called shadow password system. On those unices the pw_passwd field only contains an asterisk ('*') or the letter 'x' where the encrypted password is stored in a file /etc/shadow which is not world readable. Whether the pw_passwd field contains anything useful is system-dependent.

다음 항목을 정의합니다:

pwd.getpwuid(uid)

주어진 숫자 사용자 ID에 대한 암호 데이터베이스 항목을 반환합니다.

pwd.getpwnam(name)

주어진 사용자 이름에 대한 암호 데이터베이스 항목을 반환합니다.

pwd.getpwall()

사용 가능한 모든 암호 데이터베이스 항목의 리스트를 임의의 순서로 반환합니다.

더 보기

모듈 grp

그룹 데이터베이스에 대한 인터페이스, 이것과 유사합니다.

grp — The group database

이 모듈은 유닉스 그룹 데이터베이스에 대한 액세스를 제공합니다. 모든 유닉스 버전에서 사용할 수 있습니다.

Availability: Unix, not WASI, not Android, not iOS.

Group database entries are reported as a tuple-like object, whose attributes correspond to the members of the group structure (Attribute field below, see <grp.h>):

인덱스

어트리뷰트

의미

0

gr_name

그룹의 이름

1

gr_passwd

(암호화된) 그룹 암호; 종종 비어있습니다

2

gr_gid

숫자 그룹 ID

3

gr_mem

모든 그룹 구성원의 사용자 이름

gid는 정수고, 이름과 암호는 문자열이며, 구성원 목록은 문자열 리스트입니다. (대부분 사용자는 암호 데이터베이스에 따라 속한 그룹의 구성원으로 명시적으로 나열되지 않습니다. 완전한 멤버십 정보를 얻으려면 두 데이터베이스를 모두 확인하십시오. + 나 -로 시작하는 gr_name은 YP/NIS 참조일 수 있고 getgrnam() 이나 getgrgid()로 액세스하지 못할 수 있습니다.)

다음 항목을 정의합니다:

grp.getgrgid(id)

주어진 숫자 그룹 ID에 대한 그룹 데이터베이스 항목을 반환합니다. 요청된 항목을 찾을 수 없으면 KeyError가 발생합니다.

버전 3.10에서 변경: TypeError is raised for non-integer arguments like floats or strings.

grp.getgrnam(name)

지정된 그룹 이름에 대한 그룹 데이터베이스의 항목을 반환합니다. 요청된 항목을 찾을 수 없으면 KeyError가 발생합니다.

grp.getgrall()

사용 가능한 모든 그룹 항목의 리스트를 임의의 순서로 반환합니다.

더 보기

모듈 pwd

사용자 데이터베이스와의 인터페이스, 이것과 유사합니다.

termios — POSIX style tty control

이 모듈은 tty I/O 제어를 위한 POSIX 호출에 대한 인터페이스를 제공합니다. 이 호출에 대한 자세한 설명은 termios(3) [https://manpages.debian.org/termios(3)] 유닉스 매뉴얼 페이지를 참조하십시오. 설치 중에 구성된 POSIX termios 스타일 tty I/O 제어를 지원하는 유닉스 버전에서만 사용할 수 있습니다.

Availability: Unix.

이 모듈의 모든 함수는 첫 번째 인자로 파일 기술자 fd를 받아들입니다. sys.stdin.fileno()에 의해 반환된 것과 같은 정수 파일 기술자이거나, sys.stdin 자체와 같은 파일 객체 일 수 있습니다.

이 모듈은 여기에 제공된 함수로 작업하는 데 필요한 모든 상수도 정의합니다; 이것들은 C에 있는 것들과 같은 이름을 가집니다. 이 터미널 제어 인터페이스의 사용에 대한 자세한 내용은 시스템 설명서를 참조하십시오.

모듈은 다음 함수를 정의합니다:

termios.tcgetattr(fd)

다음과 같이 파일 기술자 fd에 대한 tty 어트리뷰트를 포함하는 리스트를 반환합니다: [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]. 여기서 cc는 tty 특수 문자 리스트입니다 (각기 길이 1인 문자열인데, 인덱스가 VMIN 과 VTIME 인 항목은 예외인데, 이 필드가 정의될 때 정수입니다). cc 배열의 인덱싱뿐만 아니라 플래그와 속도의 해석은 termios 모듈에 정의된 기호 상수를 사용해서 이루어져야 합니다.

termios.tcsetattr(fd, when, attributes)

Set the tty attributes for file descriptor fd from the attributes, which is a list like the one returned by tcgetattr(). The when argument determines when the attributes are changed:

termios.TCSANOW

Change attributes immediately.

termios.TCSADRAIN

Change attributes after transmitting all queued output.

termios.TCSAFLUSH

Change attributes after transmitting all queued output and discarding all queued input.

termios.tcsendbreak(fd, duration)

파일 기술자 fd에 브레이크(break)를 보냅니다. 0 duration은 0.25–0.5 초 동안 브레이크를 보냅니다; 0이 아닌 duration은 시스템 종속적인 의미가 있습니다.

termios.tcdrain(fd)

파일 기술자 fd에 기록된 모든 출력이 전송될 때까지 기다립니다.

termios.tcflush(fd, queue)

파일 기술자 fd에 계류 중인 데이터를 버립니다. queue 선택기는 어떤 큐인지를 지정합니다: 입력 큐는 TCIFLUSH, 출력 큐는 TCOFLUSH 또는 두 큐 모두는 TCIOFLUSH.

termios.tcflow(fd, action)

파일 기술자 fd에서 입력 또는 출력을 일시 중단하거나 다시 시작합니다. action 인자는 출력을 일시 중단하는 TCOOFF, 출력을 다시 시작하는 TCOON, 입력을 일시 중단하는 TCIOFF 또는 입력을 다시 시작하는 TCION가 될 수 있습니다.

termios.tcgetwinsize(fd)

Return a tuple (ws_row, ws_col) containing the tty window size for file descriptor fd. Requires termios.TIOCGWINSZ or termios.TIOCGSIZE.

Added in version 3.11.

termios.tcsetwinsize(fd, winsize)

Set the tty window size for file descriptor fd from winsize, which is a two-item tuple (ws_row, ws_col) like the one returned by tcgetwinsize(). Requires at least one of the pairs (termios.TIOCGWINSZ, termios.TIOCSWINSZ); (termios.TIOCGSIZE, termios.TIOCSSIZE) to be defined.

Added in version 3.11.

더 보기

모듈 tty

공통 터미널 제어 연산을 위한 편리 함수.

예제

이것은 에코가 꺼진 상태에서 암호를 묻는 함수입니다. 별도의 tcgetattr() 호출과 try … finally 문을 사용하여 이전 tty 어트리뷰트가 어떤 일이 발생하든 정확하게 복원되도록 하는 것에 유의하십시오:

def getpass(prompt="Password: "):
    import termios, sys
    fd = sys.stdin.fileno()
    old = termios.tcgetattr(fd)
    new = termios.tcgetattr(fd)
    new[3] = new[3] & ~termios.ECHO          # lflags
    try:
        termios.tcsetattr(fd, termios.TCSADRAIN, new)
        passwd = input(prompt)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old)
    return passwd

tty — Terminal control functions

소스 코드: Lib/tty.py [https://github.com/python/cpython/tree/main/Lib/tty.py]

tty 모듈은 tty를 cbreak 및 raw 모드로 설정하는 함수를 정의합니다.

Availability: Unix.

termios 모듈이 필요하기 때문에 유닉스에서만 작동합니다.

tty 모듈은 다음 함수를 정의합니다.:

tty.cfmakeraw(mode)

Convert the tty attribute list mode, which is a list like the one returned by termios.tcgetattr(), to that of a tty in raw mode.

Added in version 3.12.

tty.cfmakecbreak(mode)

Convert the tty attribute list mode, which is a list like the one returned by termios.tcgetattr(), to that of a tty in cbreak mode.

This clears the ECHO and ICANON local mode flags in mode as well as setting the minimum input to 1 byte with no delay.

Added in version 3.12.

버전 3.12.2에서 변경: The ICRNL flag is no longer cleared. This matches Linux and macOS stty cbreak behavior and what setcbreak() historically did.

tty.setraw(fd, when=termios.TCSAFLUSH)

Change the mode of the file descriptor fd to raw. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr(). The return value of termios.tcgetattr() is saved before setting fd to raw mode; this value is returned.

버전 3.12에서 변경: The return value is now the original tty attributes, instead of None.

tty.setcbreak(fd, when=termios.TCSAFLUSH)

Change the mode of file descriptor fd to cbreak. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr(). The return value of termios.tcgetattr() is saved before setting fd to cbreak mode; this value is returned.

This clears the ECHO and ICANON local mode flags as well as setting the minimum input to 1 byte with no delay.

버전 3.12에서 변경: The return value is now the original tty attributes, instead of None.

버전 3.12.2에서 변경: The ICRNL flag is no longer cleared. This restores the behavior of Python 3.11 and earlier as well as matching what Linux, macOS, & BSDs describe in their stty(1) man pages regarding cbreak mode.

더 보기

모듈 termios

저수준 터미널 제어 인터페이스.

pty — Pseudo-terminal utilities

소스 코드: Lib/pty.py [https://github.com/python/cpython/tree/main/Lib/pty.py]

pty 모듈은 의사 터미널 개념을 처리하기 위한 연산을 정의합니다: 다른 프로세스를 시작하고, 그것의 제어 터미널에 프로그래밍 방식으로 쓰고 읽습니다.

Availability: Unix.

Pseudo-terminal handling is highly platform dependent. This code is mainly tested on Linux, FreeBSD, and macOS (it is supposed to work on other POSIX platforms but it’s not been thoroughly tested).

pty 모듈은 다음 함수를 정의합니다:

pty.fork()

포크. 자식의 제어 터미널을 의사 터미널에 연결합니다. 반환 값은 (pid, fd)입니다. 자식은 pid 0을 받고, fd는 유효하지 않음에 유의하십시오. 부모의 반환 값은 자식의 pid이고, fd는 자식의 제어 터미널(또한, 자식의 표준 입력과 출력)에 연결된 파일 기술자입니다.

경고

On macOS the use of this function is unsafe when mixed with using higher-level system APIs, and that includes using urllib.request.

pty.openpty()

가능하면 os.openpty()를 사용하고, 그렇지 않으면 일반 유닉스 시스템을 위한 에뮬레이션 코드를 사용해서 새로운 의사 터미널 쌍을 엽니다. 각각 마스터와 슬레이브인 파일 기술자 쌍 (master, slave)를 반환합니다.

pty.spawn(argv[, master_read[, stdin_read]])

프로세스를 스폰하고, 그것의 제어 터미널을 현재 프로세스의 표준 입출력과 연결합니다. 이것은 종종 제어 터미널에서 읽으려고 하는 프로그램을 조절하는 데 사용됩니다. pty 뒤에 스폰된 프로세스가 결국 종료할 것으로 기대하고, 그 때 spawn이 반환됩니다.

A loop copies STDIN of the current process to the child and data received from the child to STDOUT of the current process. It is not signaled to the child if STDIN of the current process closes down.

The functions master_read and stdin_read are passed a file descriptor which they should read from, and they should always return a byte string. In order to force spawn to return before the child process exits an empty byte array should be returned to signal end of file.

두 함수의 기본 구현은 함수가 호출될 때마다 최대 1024바이트를 읽고 반환합니다. master_read 콜백으로 의사 터미널의 마스터 파일 기술자가 전달되어 자식 프로세스의 출력을 읽으며, stdin_read는 파일 기술자 0을 전달받아, 부모 프로세스의 표준 입력을 읽습니다.

두 콜백 중 하나가 빈 바이트열을 반환하는 것은 파일 끝(EOF) 조건으로 해석되며, 그 이후로 해당 콜백은 호출되지 않습니다. stdin_read가 EOF 신호를 보내면 제어 터미널은 더는 부모 프로세스나 자식 프로세스와 통신할 수 없습니다. 자식 프로세스가 입력 없이 종료하지 않는 한, spawn은 영원히 반복됩니다. master_read가 EOF 신호를 보내면 같은 동작으로 이어집니다 (적어도 리눅스에서는).

자식 프로세스에 대한 os.waitpid()로부터 온 종료 상태 값을 반환합니다.

os.waitstatus_to_exitcode() can be used to convert the exit status into an exit code.

인자 argv로 감사 이벤트 pty.spawn을 발생시킵니다.

버전 3.4에서 변경: 이제 spawn()은 자식 프로세스에 대한 os.waitpid()로부터 온 상태 값을 반환합니다.

예제

다음 프로그램은 유닉스 명령 script(1) [https://manpages.debian.org/script(1)]과 유사하게 동작하며, 의사 터미널을 사용하여 터미널 세션의 모든 입력과 출력을 “typescript”에 기록합니다.

import argparse
import os
import pty
import sys
import time

parser = argparse.ArgumentParser()
parser.add_argument('-a', dest='append', action='store_true')
parser.add_argument('-p', dest='use_python', action='store_true')
parser.add_argument('filename', nargs='?', default='typescript')
options = parser.parse_args()

shell = sys.executable if options.use_python else os.environ.get('SHELL', 'sh')
filename = options.filename
mode = 'ab' if options.append else 'wb'

with open(filename, mode) as script:
    def read(fd):
        data = os.read(fd, 1024)
        script.write(data)
        return data

    print('Script started, file is', filename)
    script.write(('Script started on %s\n' % time.asctime()).encode())

    pty.spawn(shell, read)

    script.write(('Script done on %s\n' % time.asctime()).encode())
    print('Script done, file is', filename)

fcntl — The fcntl and ioctl system calls

This module performs file and I/O control on file descriptors. It is an interface to the fcntl() and ioctl() Unix routines. See the fcntl(2) [https://manpages.debian.org/fcntl(2)] and ioctl(2) [https://manpages.debian.org/ioctl(2)] Unix manual pages for full details.

Availability: Unix, not WASI.

이 모듈의 모든 함수는 첫 번째 인자로 파일 기술자 fd를 받아들입니다. 이것은 sys.stdin.fileno()에 의해 반환된 것과 같은 정수 파일 기술자이거나 sys.stdin 자체와 같은 io.IOBase 객체일 수 있습니다. 이 객체는 실제 파일 기술자를 반환하는 fileno()를 제공합니다.

버전 3.3에서 변경: 이 모듈의 연산은 IOError를 발생시켰는데, 이제는 OSError를 발생시킵니다.

버전 3.8에서 변경: The fcntl module now contains F_ADD_SEALS, F_GET_SEALS, and F_SEAL_* constants for sealing of os.memfd_create() file descriptors.

버전 3.9에서 변경: On macOS, the fcntl module exposes the F_GETPATH constant, which obtains the path of a file from a file descriptor. On Linux(>=3.15), the fcntl module exposes the F_OFD_GETLK, F_OFD_SETLK and F_OFD_SETLKW constants, which are used when working with open file description locks.

버전 3.10에서 변경: On Linux >= 2.6.11, the fcntl module exposes the F_GETPIPE_SZ and F_SETPIPE_SZ constants, which allow to check and modify a pipe’s size respectively.

버전 3.11에서 변경: On FreeBSD, the fcntl module exposes the F_DUP2FD and F_DUP2FD_CLOEXEC constants, which allow to duplicate a file descriptor, the latter setting FD_CLOEXEC flag in addition.

버전 3.12에서 변경: On Linux >= 4.5, the fcntl module exposes the FICLONE and FICLONERANGE constants, which allow to share some data of one file with another file by reflinking on some filesystems (e.g., btrfs, OCFS2, and XFS). This behavior is commonly referred to as “copy-on-write”.

버전 3.13에서 변경: On Linux >= 2.6.32, the fcntl module exposes the F_GETOWN_EX, F_SETOWN_EX, F_OWNER_TID, F_OWNER_PID, F_OWNER_PGRP constants, which allow to direct I/O availability signals to a specific thread, process, or process group. On Linux >= 4.13, the fcntl module exposes the F_GET_RW_HINT, F_SET_RW_HINT, F_GET_FILE_RW_HINT, F_SET_FILE_RW_HINT, and RWH_WRITE_LIFE_* constants, which allow to inform the kernel about the relative expected lifetime of writes on a given inode or via a particular open file description. On Linux >= 5.1 and NetBSD, the fcntl module exposes the F_SEAL_FUTURE_WRITE constant for use with F_ADD_SEALS and F_GET_SEALS operations. On FreeBSD, the fcntl module exposes the F_READAHEAD, F_ISUNIONSTACK, and F_KINFO constants. On macOS and FreeBSD, the fcntl module exposes the F_RDAHEAD constant. On NetBSD and AIX, the fcntl module exposes the F_CLOSEM constant. On NetBSD, the fcntl module exposes the F_MAXFD constant. On macOS and NetBSD, the fcntl module exposes the F_GETNOSIGPIPE and F_SETNOSIGPIPE constant.

이 모듈은 다음 함수를 정의합니다:

fcntl.fcntl(fd, cmd, arg=0)

파일 기술자 fd(fileno() 메서드를 제공하는 파일 객체도 허용됩니다)에 대해 cmd 연산을 수행합니다. cmd에 사용되는 값은 운영 체제에 따라 다르며, 관련 C 헤더 파일에 사용된 것과 같은 이름을 사용하여 fcntl 모듈에서 상수로 제공됩니다. 인자 arg는 정숫값이나 bytes 객체가 될 수 있습니다. 정숫값일 때, 이 함수의 반환 값은 C fcntl() 호출의 정수 반환 값입니다. 인자가 바이트열일 때 바이너리 구조체를 나타냅니다, 예를 들어 struct.pack()으로 만든 것입니다. 바이너리 데이터는 주소가 C fcntl() 호출에 전달될 버퍼로 복사됩니다. 호출 성공 후 반환 값은 버퍼 내용이며, bytes 객체로 변환됩니다. 반환된 객체의 길이는 arg 인자의 길이와 같습니다. 이것은 1024바이트로 제한됩니다. 운영 체제에 의해 버퍼로 반환된 정보가 1024바이트보다 크면, 세그멘테이션 위반이나 더 미묘한 데이터 손상이 발생할 가능성이 큽니다.

If the fcntl() call fails, an OSError is raised.

인자 fd, cmd, arg로 감사 이벤트 fcntl.fcntl을 발생시킵니다.

fcntl.ioctl(fd, request, arg=0, mutate_flag=True)

이 함수는 인자 처리가 훨씬 더 복잡하다는 점을 제외하면, fcntl() 함수와 같습니다.

request 매개 변수는 32비트에 맞출 수 있는 값으로 제한됩니다. request 인자로 사용하기 위한 추가 상수는 관련 C 헤더 파일에서 사용된 것과 같은 이름으로 termios 모듈에서 제공됩니다.

매개 변수 arg는 정수, 읽기 전용 버퍼 인터페이스를 지원하는 (bytes 같은) 객체 또는 읽기-쓰기 버퍼 인터페이스를 지원하는 (bytearray 같은) 객체 중 하나일 수 있습니다.

마지막 경우를 제외하고는, 동작이 fcntl() 함수와 같습니다.

가변 버퍼가 전달되면, 동작은 mutate_flag 매개 변수의 값에 의해 결정됩니다.

거짓이면, 버퍼의 가변성은 무시되고 동작은 읽기 전용 버퍼일 때와 같습니다. 단, 위에서 언급한 1024바이트 제한은 피할 수 있습니다 – 최소한 전달한 버퍼가 운영 체제가 원하는 만큼 길면 작동해야 합니다.

mutate_flag가 참(기본값)이면, 버퍼가 (결과적으로) 하부 ioctl() 시스템 호출로 전달되고, 이 호출의 반환 코드는 호출하는 파이썬으로 다시 전달되고 버퍼의 새로운 내용은 ioctl()의 동작을 반영합니다. 이것은 약간 단순화한 설명인데, 제공된 버퍼가 1024바이트보다 작으면, 1024바이트 길이의 정적 버퍼에 먼저 복사된 다음, 이 정적 버퍼가 ioctl()로 전달되고, 정적 버퍼를 제공된 버퍼로 다시 복사하기 때문입니다.

If the ioctl() call fails, an OSError exception is raised.

예제:

>>> import array, fcntl, struct, termios, os
>>> os.getpgrp()
13341
>>> struct.unpack('h', fcntl.ioctl(0, termios.TIOCGPGRP, "  "))[0]
13341
>>> buf = array.array('h', [0])
>>> fcntl.ioctl(0, termios.TIOCGPGRP, buf, 1)
0
>>> buf
array('h', [13341])

인자 fd, request, arg로 감사 이벤트 fcntl.ioctl을 발생시킵니다.

fcntl.flock(fd, operation)

파일 기술자 fd(fileno() 메서드를 제공하는 파일 객체도 허용됩니다)에 대한 잠금 연산 operation을 수행합니다. 자세한 내용은 유닉스 매뉴얼 flock(2) [https://manpages.debian.org/flock(2)]를 참조하십시오. (일부 시스템에서는, 이 함수가 fcntl()를 사용하여 에뮬레이트됩니다.)

If the flock() call fails, an OSError exception is raised.

인자 fd, operation으로 감사 이벤트 fcntl.flock을 발생시킵니다.

fcntl.lockf(fd, cmd, len=0, start=0, whence=0)

이것은 본질에서 fcntl() 잠금 호출에 대한 래퍼입니다. fd는 잠그거나 잠금 해제할 파일의 파일 기술자이고 (fileno() 메서드를 제공하는 파일 객체도 허용됩니다), cmd는 다음 값 중 하나입니다:

fcntl.LOCK_UN

Release an existing lock.

fcntl.LOCK_SH

Acquire a shared lock.

fcntl.LOCK_EX

Acquire an exclusive lock.

fcntl.LOCK_NB

Bitwise OR with any of the other three LOCK_* constants to make the request non-blocking.

If LOCK_NB is used and the lock cannot be acquired, an OSError will be raised and the exception will have an errno attribute set to EACCES or EAGAIN (depending on the operating system; for portability, check for both values). On at least some systems, LOCK_EX can only be used if the file descriptor refers to a file opened for writing.

len은 잠글 바이트 수, start는 whence가 정의하는 기준으로 잠금이 시작되는 바이트 오프셋이며 whence는 io.IOBase.seek()에서와 같은데, 구체적으로 다음과 같습니다:

0 – relative to the start of the file (os.SEEK_SET)

1 – relative to the current buffer position (os.SEEK_CUR)

2 – relative to the end of the file (os.SEEK_END)

start의 기본값은 파일 시작 부분에서 시작한다는 의미인 0입니다. len의 기본값은 파일 끝까지 잠그는 것을 의미하는 0입니다. whence의 기본값도 0입니다.

인자 fd, cmd, len, start, whence로 감사 이벤트 fcntl.lockf를 발생시킵니다.

예제 (모두 SVR4 호환 시스템에서):

import struct, fcntl, os

f = open(...)
rv = fcntl.fcntl(f, fcntl.F_SETFL, os.O_NDELAY)

lockdata = struct.pack('hhllhh', fcntl.F_WRLCK, 0, 0, 0, 0, 0)
rv = fcntl.fcntl(f, fcntl.F_SETLKW, lockdata)

첫 번째 예제에서 반환 값 변수 rv는 정숫값을 저장합니다; 두 번째 예제에서는 bytes 객체를 저장합니다. lockdata 변수에 대한 구조체 배치는 시스템 종속적입니다 — 그래서 flock() 호출을 사용하는 것이 더 좋을 수 있습니다.

더 보기

모듈 os

If the locking flags O_SHLOCK and O_EXLOCK are present in the os module (on BSD only), the os.open() function provides an alternative to the lockf() and flock() functions.

resource — Resource usage information

이 모듈은 프로그램에서 사용하는 시스템 자원을 측정하고 제어하기 위한 기본 메커니즘을 제공합니다.

Availability: Unix, not WASI.

기호 상수는 특정 시스템 자원을 지정하고 현재 프로세스나 그 자식들에 대한 사용 정보를 요청하는 데 사용됩니다.

시스템 호출(syscall) 실패 시 OSError가 발생합니다.

exception resource.error

폐지된 OSError의 별칭.

버전 3.3에서 변경: PEP 3151 [https://peps.python.org/pep-3151/]에 따라, 이 클래스는 OSError의 별칭이 되었습니다.

자원 제한

아래 설명된 setrlimit() 함수를 사용하여 자원 사용량을 제한 할 수 있습니다. 각 자원은 제한의 쌍으로 제어됩니다: 소프트 제한과 하드 제한. 소프트 제한은 현재 제한이며, 시간이 지남에 따라 프로세스에 의해 낮아지거나 높아질 수 있습니다. 소프트 제한은 하드 제한을 초과할 수 없습니다. 하드 제한은 소프트 제한보다 큰 값으로 낮출 수 있지만, 높일 수는 없습니다. (슈퍼 유저의 유효 UID를 갖는 프로세스만 하드 제한을 높일 수 있습니다.)

제한될 수 있는 구체적인 자원은 시스템에 따라 다릅니다. getrlimit(2) [https://manpages.debian.org/getrlimit(2)] 매뉴얼 페이지에 설명되어 있습니다. 아래에 나열된 자원은 하부 운영 체제에서 지원할 때 지원됩니다; 운영 체제에서 검사하거나 제어할 수 없는 자원은 해당 플랫폼에서는 이 모듈에서 정의되지 않습니다.

resource.RLIM_INFINITY

무제한 자원의 제한을 나타내는 데 사용되는 상수.

resource.getrlimit(resource)

resource의 현재 소프트와 하드 제한인 튜플 (soft, hard)를 반환합니다. 유효하지 않은 resource가 지정되면 ValueError가 발생하고, 하부 시스템 호출이 예기치 않게 실패하면 error가 발생합니다.

resource.setrlimit(resource, limits)

resource의 새로운 소비 제한을 설정합니다. limits 인자는 새로운 제한을 설명하는 두 정수의 튜플 (soft, hard)이어야 합니다. RLIM_INFINITY 값을 사용하여 무제한 제한을 요청할 수 있습니다.

유효하지 않은 resource가 지정되거나, 새 소프트 제한이 하드 제한을 초과하거나, 프로세스가 하드 제한을 높이려고 시도하면 ValueError가 발생합니다. 해당 자원의 하드나 시스템 제한이 무제한이 아닐 때 RLIM_INFINITY 제한을 지정하면 ValueError가 발생합니다. 슈퍼 유저의 유효 UID를 갖는 프로세스는 무제한을 포함하여 임의의 유효한 제한 값을 요청할 수 있지만, 요청된 제한이 시스템이 부과한 제한을 초과하면 ValueError가 여전히 발생합니다.

하부 시스템 호출이 실패하면 setrlimit도 error를 발생시킬 수 있습니다.

VxWorks는 RLIMIT_NOFILE 설정만 지원합니다.

인자 resource, limits로 감사 이벤트 resource.setrlimit를 발생시킵니다.

resource.prlimit(pid, resource[, limits])

하나의 함수에서 setrlimit()와 getrlimit()를 결합하고 임의 프로세스의 자원 제한을 가져오고 설정하도록 지원합니다. pid가 0이면, 호출은 현재 프로세스에 적용됩니다. resource와 limits는 limits가 선택적이라는 점을 제외하고 setrlimit()와 같은 의미입니다.

limits가 제공되지 않으면 함수는 프로세스 pid의 resource 제한을 반환합니다. limits가 제공되면 프로세스의 resource 제한이 설정되고 이전 자원 제한이 반환됩니다.

pid를 찾을 수 없으면 ProcessLookupError가 발생하고 사용자가 프로세스에 대해 CAP_SYS_RESOURCE가 없으면 PermissionError가 발생합니다.

인자 pid, resource, limits로 감사 이벤트 resource.prlimit를 발생시킵니다.

Availability: Linux >= 2.6.36 with glibc >= 2.13.

Added in version 3.4.

이 기호들은 setrlimit()와 getrlimit() 함수를 사용하여 소비를 제어할 수 있는 아래 설명된 자원을 정의합니다. 이 기호의 값은 정확히 C 프로그램에서 사용하는 상수입니다.

getrlimit(2) [https://manpages.debian.org/getrlimit(2)]에 관한 유닉스 매뉴얼 페이지는 사용 가능한 자원을 나열합니다. 모든 시스템이 같은 자원을 나타내는 데 같은 기호나 같은 값을 사용하는 것은 아닙니다. 이 모듈은 플랫폼 차이를 감추려고 시도하지 않습니다 — 플랫폼에서 정의되지 않은 기호는 해당 플랫폼에서 이 모듈에서 제공되지 않습니다.

resource.RLIMIT_CORE

현재 프로세스가 만들 수 있는 코어(core) 파일의 최대 크기 (바이트). 전체 프로세스 이미지를 담기 위해 더 큰 코어가 필요할 때 부분 코어 파일이 생성될 수 있습니다.

resource.RLIMIT_CPU

프로세스가 사용할 수 있는 최대 프로세서 시간 (초). 이 제한을 초과하면, SIGXCPU 시그널이 프로세스로 전송됩니다. (이 시그널을 포착하고, 열려있는 파일을 디스크로 플러시 하는 등 유용한 작업을 수행하는 방법에 대한 정보는 signal 모듈 설명서를 참조하십시오.)

resource.RLIMIT_FSIZE

프로세스가 만들 수 있는 파일의 최대 크기.

resource.RLIMIT_DATA

프로세스 힙(heap)의 최대 크기 (바이트).

resource.RLIMIT_STACK

현재 프로세스에 대한 호출 스택의 최대 크기 (바이트). 이것은 다중 스레드 프로세스에서 메인 스레드의 스택에만 영향을 줍니다.

resource.RLIMIT_RSS

프로세스에서 사용할 수 있는 최대 상주 집합(resident set) 크기.

resource.RLIMIT_NPROC

현재 프로세스가 만들 수 있는 최대 프로세스 수.

resource.RLIMIT_NOFILE

현재 프로세스에 대한 열린 파일 기술자의 최대 수.

resource.RLIMIT_OFILE

RLIMIT_NOFILE의 BSD 이름.

resource.RLIMIT_MEMLOCK

메모리에 잠겨 있을 수 있는 최대 주소 공간.

resource.RLIMIT_VMEM

프로세스가 차지할 수 있는 가장 큰 매핑된 메모리(mapped memory) 영역.

Availability: FreeBSD >= 11.

resource.RLIMIT_AS

프로세스에서 사용할 수 있는 주소 공간의 최대 영역 (바이트).

resource.RLIMIT_MSGQUEUE

POSIX 메시지 큐에 할당할 수 있는 바이트 수.

Availability: Linux >= 2.6.8.

Added in version 3.4.

resource.RLIMIT_NICE

프로세스의 나이스(nice) 수준의 상한 (20 - rlim_cur로 계산됩니다).

Availability: Linux >= 2.6.12.

Added in version 3.4.

resource.RLIMIT_RTPRIO

실시간 우선순위의 상한.

Availability: Linux >= 2.6.12.

Added in version 3.4.

resource.RLIMIT_RTTIME

프로세스가 블로킹 시스템 호출 없이 실시간 스케줄링 하에서 소비할 수 있는 CPU 시간의 시간제한 (마이크로초).

Availability: Linux >= 2.6.25.

Added in version 3.4.

resource.RLIMIT_SIGPENDING

프로세스가 큐에 넣을 수 있는 시그널 수입니다.

Availability: Linux >= 2.6.8.

Added in version 3.4.

resource.RLIMIT_SBSIZE

이 사용자의 소켓 버퍼 사용량의 최대 크기 (바이트). 이것은 이 사용자가 모든 시점에 보유할 수 있는 네트워크 메모리양과 mbuf들의 양을 제한합니다.

Availability: FreeBSD.

Added in version 3.4.

resource.RLIMIT_SWAP

The maximum size (in bytes) of the swap space that may be reserved or used by all of this user id’s processes. This limit is enforced only if bit 1 of the vm.overcommit sysctl is set. Please see tuning(7) [https://man.freebsd.org/cgi/man.cgi?query=tuning&sektion=7] for a complete description of this sysctl.

Availability: FreeBSD.

Added in version 3.4.

resource.RLIMIT_NPTS

이 사용자 ID로 만들어지는 최대 의사 터미널(pseudo-terminal) 수.

Availability: FreeBSD.

Added in version 3.4.

resource.RLIMIT_KQUEUES

The maximum number of kqueues this user id is allowed to create.

Availability: FreeBSD >= 11.

Added in version 3.10.

자원 사용량

이 함수는 자원 사용량 정보를 조회하는 데 사용됩니다:

resource.getrusage(who)

This function returns an object that describes the resources consumed by either the current process or its children, as specified by the who parameter. The who parameter should be specified using one of the RUSAGE_* constants described below.

간단한 예:

from resource import *
import time

# a non CPU-bound task
time.sleep(3)
print(getrusage(RUSAGE_SELF))

# a CPU-bound task
for i in range(10 ** 8):
   _ = 1 + 1
print(getrusage(RUSAGE_SELF))

반환 값의 필드는 각각 특정 시스템 자원이 어떻게 사용되었는지를 설명합니다. 예를 들어, 사용자 모드로 실행에 든 시간이나 프로세스가 주 메모리에서 스와프된 횟수. 일부 값은 클록 틱(clock tick) 내부에 의존합니다, 예를 들어, 프로세스에서 사용 중인 메모리양.

이전 버전과의 호환성을 위해, 반환 값은 16개 요소의 튜플로 액세스 할 수도 있습니다.

The fields ru_utime and ru_stime of the return value are floating-point values representing the amount of time spent executing in user mode and the amount of time spent executing in system mode, respectively. The remaining values are integers. Consult the getrusage(2) [https://manpages.debian.org/getrusage(2)] man page for detailed information about these values. A brief summary is presented here:

인덱스

필드

자원

0

ru_utime

사용자 모드의 시간 (float 초)

1

ru_stime

시스템 모드의 시간 (float 초)

2

ru_maxrss

최대 상주 집합(resident set) 크기

3

ru_ixrss

공유 메모리 크기

4

ru_idrss

비공유 메모리 크기

5

ru_isrss

비공유 스택 크기

6

ru_minflt

I/O가 필요 없는 페이지 폴트(page fault)

7

ru_majflt

I/O가 필요한 페이지 폴트(page fault)

8

ru_nswap

스와프(swap out) 수

9

ru_inblock

블록 입력 연산(block input operations)

10

ru_oublock

블록 출력 연산(block output operations)

11

ru_msgsnd

보낸 메시지

12

ru_msgrcv

받은 메시지

13

ru_nsignals

받은 시그널

14

ru_nvcsw

자발적 컨텍스트 전환(voluntary context switches)

15

ru_nivcsw

비자발적 컨텍스트 전환(involuntary context switches)

유효하지 않은 who 매개 변수가 지정되면 이 함수는 ValueError를 발생시킵니다. 비정상적인 상황에서 error 예외가 발생할 수도 있습니다.

resource.getpagesize()

시스템 페이지의 바이트 수를 반환합니다. (하드웨어 페이지 크기와 같을 필요는 없습니다.)

The following RUSAGE_* symbols are passed to the getrusage() function to specify which processes information should be provided for.

resource.RUSAGE_SELF

호출하는 프로세스가 소비한 자원을 요청하기 위해 getrusage()로 전달합니다. 이는 프로세스의 모든 스레드가 사용하는 자원의 합계입니다.

resource.RUSAGE_CHILDREN

호출하는 프로세스의 종료되어 기다리고 있는 자식 프로세스에서 소비한 자원을 요청하기 위해 getrusage()로 전달합니다.

resource.RUSAGE_BOTH

현재 프로세스와 자식 프로세스 모두에서 소비한 자원을 요청하기 위해 getrusage()로 전달합니다. 모든 시스템에서 사용 가능한 것은 아닙니다.

resource.RUSAGE_THREAD

현재 스레드가 소비한 자원을 요청하기 위해 getrusage()에 전달합니다. 모든 시스템에서 사용 가능한 것은 아닙니다.

Added in version 3.2.

syslog — Unix syslog library routines

이 모듈은 유닉스 syslog 라이브러리 루틴에 대한 인터페이스를 제공합니다. syslog 기능에 대한 자세한 설명은 유닉스 매뉴얼 페이지를 참조하십시오.

Availability: Unix, not WASI, not iOS.

This module wraps the system syslog family of routines. A pure Python library that can speak to a syslog server is available in the logging.handlers module as SysLogHandler.

모듈은 다음 함수를 정의합니다:

syslog.syslog(message)

syslog.syslog(priority, message)

message 문자열을 시스템 로거로 보냅니다. 필요하면 끝에 줄 넘김이 추가됩니다. 각 메시지에는 시설(facility) 과 수준(level)으로 구성된 우선순위(priority)로 꼬리표가 붙습니다. 선택적 priority 인자(기본값은 LOG_INFO)는 메시지 우선순위를 결정합니다. 시설이 논리합(LOG_INFO | LOG_USER)을 사용하여 priority로 인코딩되지 않으면, openlog() 호출에 지정된 값이 사용됩니다.

If openlog() has not been called prior to the call to syslog(), openlog() will be called with no arguments.

인자 priority, message로 감사 이벤트 syslog.syslog를 발생시킵니다.

버전 3.2에서 변경: In previous versions, openlog() would not be called automatically if it wasn’t called prior to the call to syslog(), deferring to the syslog implementation to call openlog().

버전 3.12에서 변경: This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) openlog() must be called in the main interpreter before syslog() may be used in a subinterpreter. Otherwise it will raise RuntimeError.

syslog.openlog([ident[, logoption[, facility]]])

후속 syslog() 호출의 로깅 옵션은 openlog()를 호출하여 설정할 수 있습니다. 로그가 현재 열려 있지 않으면 syslog()는 인자 없이 openlog()를 호출합니다.

선택적 ident 키워드 인자는 모든 메시지 앞에 추가되는 문자열이며, 기본값은 선행 경로 구성 요소가 제거된 sys.argv[0]입니다. 선택적 logoption 키워드 인자(기본값은 0)는 비트 필드입니다 – 결합할 수 있는 가능한 값은 아래를 보십시오. 선택적 facility 키워드 인자(기본값은 LOG_USER)는 명시적으로 인코드 된 시설이 없는 메시지에 대한 기본 시설을 설정합니다.

인자 ident, logoption, facility로 감사 이벤트 syslog.openlog를 발생시킵니다.

버전 3.2에서 변경: In previous versions, keyword arguments were not allowed, and ident was required.

버전 3.12에서 변경: This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) This may only be called in the main interpreter. It will raise RuntimeError if called in a subinterpreter.

syslog.closelog()

syslog 모듈값을 재설정하고 시스템 라이브러리 closelog()를 호출합니다.

이것은 모듈이 처음 임포트될 때처럼 작동하도록 합니다. 예를 들어, openlog()는 첫 번째 syslog() 호출에서 호출되며(openlog()가 아직 호출되지 않았다면), ident 와 기타 openlog() 매개 변수가 기본값으로 재설정됩니다.

인자 없이 감사 이벤트 syslog.closelog를 발생시킵니다.

버전 3.12에서 변경: This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) This may only be called in the main interpreter. It will raise RuntimeError if called in a subinterpreter.

syslog.setlogmask(maskpri)

우선순위 마스크를 maskpri로 설정하고 이전 마스크값을 반환합니다. maskpri에 설정되지 않은 우선순위 수준으로 syslog()를 호출하면 무시됩니다. 기본값은 모든 우선순위를 로그 하는 것입니다. 함수 LOG_MASK(pri)는 개별 우선순위 pri에 대한 마스크를 계산합니다. 함수 LOG_UPTO(pri)는 pri까지의 모든 우선순위에 대한 마스크를 계산합니다.

인자 maskpri로 감사 이벤트 syslog.setlogmask를 발생시킵니다.

모듈은 다음 상수를 정의합니다:

syslog.LOG_EMERG

syslog.LOG_ALERT

syslog.LOG_CRIT

syslog.LOG_ERR

syslog.LOG_WARNING

syslog.LOG_NOTICE

syslog.LOG_INFO

syslog.LOG_DEBUG

Priority levels (high to low).

syslog.LOG_AUTH

syslog.LOG_AUTHPRIV

syslog.LOG_CRON

syslog.LOG_DAEMON

syslog.LOG_FTP

syslog.LOG_INSTALL

syslog.LOG_KERN

syslog.LOG_LAUNCHD

syslog.LOG_LPR

syslog.LOG_MAIL

syslog.LOG_NETINFO

syslog.LOG_NEWS

syslog.LOG_RAS

syslog.LOG_REMOTEAUTH

syslog.LOG_SYSLOG

syslog.LOG_USER

syslog.LOG_UUCP

syslog.LOG_LOCAL0

syslog.LOG_LOCAL1

syslog.LOG_LOCAL2

syslog.LOG_LOCAL3

syslog.LOG_LOCAL4

syslog.LOG_LOCAL5

syslog.LOG_LOCAL6

syslog.LOG_LOCAL7

Facilities, depending on availability in <syslog.h> for LOG_AUTHPRIV, LOG_FTP, LOG_NETINFO, LOG_REMOTEAUTH, LOG_INSTALL and LOG_RAS.

버전 3.13에서 변경: Added LOG_FTP, LOG_NETINFO, LOG_REMOTEAUTH, LOG_INSTALL, LOG_RAS, and LOG_LAUNCHD.

syslog.LOG_PID

syslog.LOG_CONS

syslog.LOG_NDELAY

syslog.LOG_ODELAY

syslog.LOG_NOWAIT

syslog.LOG_PERROR

Log options, depending on availability in <syslog.h> for LOG_ODELAY, LOG_NOWAIT and LOG_PERROR.

예제

간단한 예제

간단한 예제 집합:

import syslog

syslog.syslog('Processing started')
if error:
    syslog.syslog(syslog.LOG_ERR, 'Processing started')

일부 로그 옵션 설정의 예, 이것은 로그 메시지에 프로세스 ID를 포함하며, 메일 로깅에 사용되는 대상 시설로 메시지를 기록합니다:

syslog.openlog(logoption=syslog.LOG_PID, facility=syslog.LOG_MAIL)
syslog.syslog('E-mail processing initiated...')

Modules command-line interface (CLI)

The following modules have a command-line interface.

ast

asyncio

base64

calendar

code

compileall

cProfile: see profile

difflib

dis

doctest

encodings.rot_13

ensurepip

filecmp

fileinput

ftplib

gzip

http.server

idlelib

inspect

json

mimetypes

pdb

pickle

pickletools

platform

poplib

profile

pstats

py_compile

pyclbr

pydoc

quopri

random

runpy

site

sqlite3

symtable

sysconfig

tabnanny

tarfile

this

timeit

tokenize

trace

turtledemo

unittest

uuid

venv

webbrowser

zipapp

zipfile

See also the Python command-line interface.

대체된 모듈

The modules described in this chapter are deprecated or soft deprecated and only kept for backwards compatibility. They have been superseded by other modules.

getopt — C-style parser for command line options

optparse — Parser for command line options

getopt — C-style parser for command line options

소스 코드: Lib/getopt.py [https://github.com/python/cpython/tree/main/Lib/getopt.py]

버전 3.13부터 폐지됨: The getopt module is soft deprecated and will not be developed further; development will continue with the argparse module.

참고

The getopt module is a parser for command line options whose API is designed to be familiar to users of the C getopt() function. Users who are unfamiliar with the C getopt() function or who would like to write less code and get better help and error messages should consider using the argparse module instead.

This module helps scripts to parse the command line arguments in sys.argv. It supports the same conventions as the Unix getopt() function (including the special meanings of arguments of the form ‘-’ and ‘--‘). Long options similar to those supported by GNU software may be used as well via an optional third argument.

이 모듈은 두 가지 함수와 예외를 제공합니다:

getopt.getopt(args, shortopts, longopts=[])

Parses command line options and parameter list. args is the argument list to be parsed, without the leading reference to the running program. Typically, this means sys.argv[1:]. shortopts is the string of option letters that the script wants to recognize, with options that require an argument followed by a colon (':') and options that accept an optional argument followed by two colons ('::'); i.e., the same format that Unix getopt() uses.

참고

Unlike GNU getopt(), after a non-option argument, all further arguments are considered also non-options. This is similar to the way non-GNU Unix systems work.

longopts, if specified, must be a list of strings with the names of the long options which should be supported. The leading '--' characters should not be included in the option name. Long options which require an argument should be followed by an equal sign ('='). Long options which accept an optional argument should be followed by an equal sign and question mark ('=?'). To accept only long options, shortopts should be an empty string. Long options on the command line can be recognized so long as they provide a prefix of the option name that matches exactly one of the accepted options. For example, if longopts is ['foo', 'frob'], the option --fo will match as --foo, but --f will not match uniquely, so GetoptError will be raised.

반환 값은 두 요소로 구성됩니다: 첫 번째는 (option, value) 쌍의 리스트입니다; 두 번째는 옵션 리스트가 제거된 후 남겨진 프로그램 인자 리스트입니다 (이것은 args의 후행 슬라이스입니다). 반환된 각 옵션-값 쌍은 첫 번째 요소로 옵션을 가지며, 짧은 옵션(예를 들어, '-x')은 하이픈이, 긴 옵션(예를 들어, '--long-option')은 두 개의 하이픈이 접두사로 붙고, 두 번째 요소는 옵션 인자나 옵션에 인자가 없으면 빈 문자열입니다. 옵션은 발견된 순서와 같은 순서로 리스트에 나타나므로, 여러 번 나오는 것을 허용합니다. 긴 옵션과 짧은 옵션은 혼합될 수 있습니다.

버전 3.14에서 변경: Optional arguments are supported.

getopt.gnu_getopt(args, shortopts, longopts=[])

이 함수는 기본적으로 GNU 스타일 스캔 모드가 사용된다는 점을 제외하고는 getopt()처럼 작동합니다. 이것은 옵션과 옵션이 아닌 인자가 섞일 수 있음을 뜻합니다. getopt() 함수는 옵션이 아닌 인자가 발견되자마자 옵션 처리를 중지합니다.

If the first character of the option string is '+', or if the environment variable POSIXLY_CORRECT is set, then option processing stops as soon as a non-option argument is encountered.

If the first character of the option string is '-', non-option arguments that are followed by options are added to the list of option-and-value pairs as a pair that has None as its first element and the list of non-option arguments as its second element. The second element of the gnu_getopt() result is a list of program arguments after the last option.

버전 3.14에서 변경: Support for returning intermixed options and non-option arguments in order.

exception getopt.GetoptError

This is raised when an unrecognized option is found in the argument list or when an option requiring an argument is given none. The argument to the exception is a string indicating the cause of the error. For long options, an argument given to an option which does not require one will also cause this exception to be raised. The attributes msg and opt give the error message and related option; if there is no specific option to which the exception relates, opt is an empty string.

exception getopt.error

GetoptError의 별칭; 과거 호환성을 위한 것입니다.

유닉스 스타일 옵션만 사용하는 예제:

>>> import getopt
>>> args = '-a -b -cfoo -d bar a1 a2'.split()
>>> args
['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2']
>>> optlist, args = getopt.getopt(args, 'abc:d:')
>>> optlist
[('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')]
>>> args
['a1', 'a2']

긴 옵션 이름을 사용하는 것도 똑같이 간단합니다:

>>> s = '--condition=foo --testing --output-file abc.def -x a1 a2'
>>> args = s.split()
>>> args
['--condition=foo', '--testing', '--output-file', 'abc.def', '-x', 'a1', 'a2']
>>> optlist, args = getopt.getopt(args, 'x', [
...     'condition=', 'output-file=', 'testing'])
>>> optlist
[('--condition', 'foo'), ('--testing', ''), ('--output-file', 'abc.def'), ('-x', '')]
>>> args
['a1', 'a2']

Optional arguments should be specified explicitly:

>>> s = '-Con -C --color=off --color a1 a2'
>>> args = s.split()
>>> args
['-Con', '-C', '--color=off', '--color', 'a1', 'a2']
>>> optlist, args = getopt.getopt(args, 'C::', ['color=?'])
>>> optlist
[('-C', 'on'), ('-C', ''), ('--color', 'off'), ('--color', '')]
>>> args
['a1', 'a2']

The order of options and non-option arguments can be preserved:

>>> s = 'a1 -x a2 a3 a4 --long a5 a6'
>>> args = s.split()
>>> args
['a1', '-x', 'a2', 'a3', 'a4', '--long', 'a5', 'a6']
>>> optlist, args = getopt.gnu_getopt(args, '-x:', ['long='])
>>> optlist
[(None, ['a1']), ('-x', 'a2'), (None, ['a3', 'a4']), ('--long', 'a5')]
>>> args
['a6']

In a script, typical usage is something like this:

import getopt, sys

def main():
    try:
        opts, args = getopt.getopt(sys.argv[1:], "ho:v", ["help", "output="])
    except getopt.GetoptError as err:
        # print help information and exit:
        print(err)  # will print something like "option -a not recognized"
        usage()
        sys.exit(2)
    output = None
    verbose = False
    for o, a in opts:
        if o == "-v":
            verbose = True
        elif o in ("-h", "--help"):
            usage()
            sys.exit()
        elif o in ("-o", "--output"):
            output = a
        else:
            assert False, "unhandled option"
    # ...

if __name__ == "__main__":
    main()

Note that an equivalent command line interface could be produced with less code and more informative help and error messages by using the argparse module:

import argparse

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-o', '--output')
    parser.add_argument('-v', dest='verbose', action='store_true')
    args = parser.parse_args()
    # ... do something with args.output ...
    # ... do something with args.verbose ..

더 보기

모듈 argparse

대안 명령 줄 옵션과 인자 구문 분석 라이브러리.

optparse — Parser for command line options

소스 코드: Lib/optparse.py [https://github.com/python/cpython/tree/main/Lib/optparse.py]

버전 3.2부터 폐지됨: The optparse module is soft deprecated and will not be developed further; development will continue with the argparse module.

optparse는 이전 getopt 모듈보다 명령 줄 옵션을 구문 분석하기 위한 더 편리하고 유연하며 강력한 라이브러리입니다. optparse는 더 선언적인 스타일의 명령 줄 구문 분석을 사용합니다: OptionParser의 인스턴스를 만들고, 옵션으로 채우고, 명령 줄을 구문 분석합니다. optparse를 사용하면 사용자가 전통적인 GNU/POSIX 문법으로 옵션을 지정할 수 있으며, 추가로 사용법과 도움말 메시지를 생성할 수 있습니다.

다음은 간단한 스크립트에서 optparse를 사용하는 예입니다:

from optparse import OptionParser
...
parser = OptionParser()
parser.add_option("-f", "--file", dest="filename",
                  help="write report to FILE", metavar="FILE")
parser.add_option("-q", "--quiet",
                  action="store_false", dest="verbose", default=True,
                  help="don't print status messages to stdout")

(options, args) = parser.parse_args()

이 몇 줄의 코드로, 스크립트 사용자는 이제 명령 줄에서 “일반적인 작업”을 수행 할 수 있습니다, 예를 들면:

<yourscript> --file=outfile -q

As it parses the command line, optparse sets attributes of the options object returned by parse_args() based on user-supplied command-line values. When parse_args() returns from parsing this command line, options.filename will be "outfile" and options.verbose will be False. optparse supports both long and short options, allows short options to be merged together, and allows options to be associated with their arguments in a variety of ways. Thus, the following command lines are all equivalent to the above example:

<yourscript> -f outfile --quiet
<yourscript> --quiet --file outfile
<yourscript> -q -foutfile
<yourscript> -qfoutfile

또한, 사용자는 다음 중 하나를 실행할 수 있습니다

<yourscript> -h
<yourscript> --help

그러면 optparse는 스크립트 옵션에 대한 간략한 요약을 인쇄합니다:

Usage: <yourscript> [options]

Options:
  -h, --help            show this help message and exit
  -f FILE, --file=FILE  write report to FILE
  -q, --quiet           don't print status messages to stdout

여기서 yourscript의 값은 (일반적으로 sys.argv[0]에서) 실행 시간에 결정됩니다.

배경

optparse는 간단하고 전통적인 명령 줄 인터페이스를 갖는 프로그램을 만들 수 있도록 명시적으로 설계되었습니다. 이를 위해, 유닉스에서 전통적으로 사용되는 가장 일반적인 명령 줄 문법과 의미 체계만 지원합니다. 이러한 규칙에 익숙하지 않으면, 이 섹션을 읽고 숙지하십시오.

용어

인자(argument)

명령 줄에 입력하고, 셸에서 execl()이나 execv()로 전달한 문자열. 파이썬에서, 인자는 sys.argv[1:]의 요소입니다 (sys.argv[0]은 실행 중인 프로그램의 이름입니다). 유닉스 셸은 “워드(word)”라는 용어도 사용합니다.

때때로 sys.argv[1:] 이외의 인자 리스트로 대체하는 것이 바람직해서, “인자”를 “sys.argv[1:]이나 sys.argv[1:]의 대체로 제공된 다른 리스트의 요소”로 읽어야 합니다.

옵션(option)

프로그램 실행을 안내하거나 사용자 정의하기 위해 추가 정보를 제공하는 데 사용되는 인자. 옵션에 대한 다양한 문법이 있습니다; 전통적인 유닉스 문법은 하이픈 (“-”) 뒤에 단일 문자가 옵니다, 예를 들어 -x나 -F. 또한, 전통적인 유닉스 문법은 여러 옵션을 단일 인자로 병합할 수 있도록 합니다, 예를 들어 -x -F는 -xF와 동등합니다. GNU 프로젝트는 하이픈으로 구분된 일련의 단어가 뒤따르는 --를 도입했습니다, 예를 들어 --file이나 --dry-run. 이들이 optparse에서 제공하는 유일한 두 가지 옵션 문법입니다.

세상에 등장했던 다른 옵션 문법은 다음과 같습니다:

몇 개의 문자가 뒤따르는 하이픈, 예를 들어 -pf (이것은 하나의 인자로 병합된 여러 옵션과 같은 것이 아닙니다)

전체 단어가 뒤따르는 하이픈, 예를 들어 -file (기술적으로 이전 문법과 동등하지만, 일반적으로 같은 프로그램에서 등장하지 않습니다)

단일 문자나 몇 개의 문자 또는 단어가 뒤따르는 더하기 기호, 예를 들어 +f, +rgb

단일 문자나 몇 개의 문자 또는 단어가 뒤따르는 슬래시, 예를 들어 /f, /file

These option syntaxes are not supported by optparse, and they never will be. This is deliberate: the first three are non-standard on any environment, and the last only makes sense if you’re exclusively targeting Windows or certain legacy platforms (e.g. VMS, MS-DOS).

옵션 인자(option argument)

옵션 뒤에 오는 인자는 해당 옵션과 밀접하게 연관되어 있으며, 해당 옵션이 있으면 인자 목록에서 사용됩니다. optparse를 사용하면, 옵션 인자가 해당 옵션과 별도의 인자로 있을 수 있습니다:

-f foo
--file foo

또는 같은 인자에 포함될 수 있습니다:

-ffoo
--file=foo

일반적으로, 주어진 옵션은 인자를 취하거나 취하지 않습니다. 많은 사람이 “선택적 옵션 인자” 기능을 원합니다. 즉, 일부 옵션은 있다면 인자를 취하고 그렇지 않으면 취하지 않습니다. 이것은 구문 분석을 모호하게 만들기 때문에 다소 논란의 여지가 있습니다: -a가 선택적 인자를 취하고 -b가 완전히 다른 옵션이면 -ab를 어떻게 해석합니까? 이러한 모호성 때문에, optparse는 이 기능을 지원하지 않습니다.

위치 인자(positional argument)

옵션이 구문 분석된 후, 즉 옵션과 해당 인자가 구문 분석되고 인자 목록에서 제거된 후 인자 목록에 남은 것.

필수 옵션(required option)

명령 줄에서 제공해야 하는 옵션; “필수 옵션”이라는 문구는 영어에서 모순된다는 점에 유의하십시오. optparse는 필수 옵션을 구현하는 것을 방해하지 않지만, 그다지 도움을 주지도 않습니다.

예를 들어, 다음 가상 명령 줄을 고려하십시오:

prog -v --report report.txt foo bar

-v와 --report는 둘 다 옵션입니다. --report가 하나의 인자를 취한다고 가정하면, report.txt는 옵션 인자입니다. foo와 bar는 위치 인자입니다.

옵션은 무엇을 위한 것입니까?

옵션은 프로그램 실행을 조정하거나 사용자 정의하기 위한 추가 정보를 제공하는 데 사용됩니다. 명확하지 않은 경우, 옵션은 일반적으로 선택적입니다. 프로그램은 어떤 옵션도 없이 잘 실행될 수 있어야 합니다. (유닉스나 GNU 도구 집합에서 임의의 프로그램을 선택하십시오. 옵션 없이도 실행될 수 있으며 여전히 의미가 있습니까? 주요 예외는 find, tar 및 dd입니다 — 모두 비표준 문법과 혼란스러운 인터페이스 때문에 올바로 비판을 받은 돌연변이 괴짜입니다.)

많은 사람이 프로그램에 “필수 옵션”이 있기를 원합니다. 생각해보십시오. 필수라면, 그것은 선택적(optional)이 아닙니다! 당신의 프로그램이 성공적으로 실행하기 위해 절대적으로 필요한 정보가 있다면, 그것이 바로 위치 인자의 목적입니다.

좋은 명령 줄 인터페이스 설계의 예로, 파일 복사를 위한 겸손한 cp 유틸리티를 고려하십시오. 대상과 하나 이상의 소스를 제공하지 않고 파일을 복사하는 것은 의미가 없습니다. 따라서, 인자 없이 실행하면 cp가 실패합니다. 그러나 옵션이 전혀 필수로 요구하지 않는 유연하고 유용한 문법을 갖습니다:

cp SOURCE DEST
cp SOURCE ... DEST-DIR

그것만으로도 꽤 멀리 갈 수 있습니다. 대부분의 cp 구현은 파일이 복사되는 방식을 정확하게 조정할 수 있는 여러 옵션을 제공합니다: 모드 및 수정 시간을 보존하고, 심볼릭 링크를 따르지 않고, 기존 파일을 건드리기 전에 물을 수 있습니다. 하지만 이 중 어느 것도 한 파일을 다른 파일로 복사하거나 여러 파일을 다른 디렉터리로 복사하는 cp의 핵심 임무를 방해하지 않습니다.

위치 인자는 무엇을 위한 것입니까?

위치 인자는 프로그램이 실행하기 위해 절대적으로 필요로하는 정보를 위한 것입니다.

좋은 사용자 인터페이스에는 가능한 한 적은 절대 요구 사항이 있어야 합니다. 프로그램을 성공적으로 실행하기 위해 17개의 개별 정보를 요구한다면, 사용자로부터 해당 정보를 어떻게 얻는지는 중요하지 않습니다—대부분의 사람은 프로그램을 성공적으로 실행하기 전에 포기하고 떠납니다. 이것은 사용자 인터페이스가 명령 줄이든, 구성 파일이든, GUI이든 상관없이 적용됩니다: 사용자에게 그렇게 많은 요구를 하면, 대부분은 단순히 포기할 것입니다.

요컨대, 사용자가 절대적으로 제공해야 하는 정보의 양을 최소화하십시오—가능할 때마다 합리적인 기본값을 사용하십시오. 물론, 프로그램을 합리적으로 유연하게 만들고 싶기도 합니다. 그것이 바로 옵션이 있는 이유입니다. 다시 말하지만, 구성 파일의 항목인지, GUI의 “기본 설정” 대화 상자에 있는 위젯인지, 명령 줄 옵션인지는 중요하지 않습니다—구현하는 옵션이 많을수록, 프로그램이 더 유연해지고, 구현은 더 복잡해집니다. 물론 유연성이 너무 많으면 단점도 있습니다; 너무 많은 옵션은 사용자를 압도하고 코드 유지 관리를 훨씬 더 어렵게 만들 수 있습니다.

자습서

optparse는 매우 유연하고 강력하지만, 대부분의 경우 사용하기도 간단합니다. 이 섹션에서는 모든 optparse 기반 프로그램에 공통적인 코드 패턴을 다룹니다.

먼저, OptionParser 클래스를 임포트 해야 합니다; 그런 다음 메인 프로그램의 초기에, OptionParser 인스턴스를 만듭니다:

from optparse import OptionParser
...
parser = OptionParser()

그런 다음 옵션 정의를 시작할 수 있습니다. 기본 문법은 다음과 같습니다:

parser.add_option(opt_str, ...,
                  attr=value, ...)

각 옵션에는 -f나 --file과 같은 하나 이상의 옵션 문자열이 있고, 명령 줄에서 해당 옵션을 발견했을 때 optparse가 기대하는 것과 수행 할 작업을 알려주는 여러 옵션 어트리뷰트가 있습니다.

일반적으로, 각 옵션에는 하나의 짧은 옵션 문자열과 하나의 긴 옵션 문자열이 있습니다, 예를 들어:

parser.add_option("-f", "--file", ...)

전체적으로 적어도 하나의 옵션 문자열이 있는 한 원하는 만큼 짧은 옵션 문자열과 긴 옵션 문자열을 (없는 것도 포함합니다) 자유롭게 정의 할 수 있습니다.

OptionParser.add_option()에 전달된 옵션 문자열은 해당 호출에 의해 정의된 옵션에 대한 레이블입니다. 간결함을 위해, 명령 줄에서 옵션을 만난다를 자주 언급할 것입니다; 실제로는, optparse가 옵션 문자열을 만나고 이것으로 옵션을 찾습니다.

일단 모든 옵션이 정의되면, optparse가 프로그램의 명령 줄을 구문 분석하도록 지시합니다:

(options, args) = parser.parse_args()

(If you like, you can pass a custom argument list to parse_args(), but that’s rarely necessary: by default it uses sys.argv[1:].)

parse_args() returns two values:

options, 모든 옵션에 대한 값을 포함하는 객체—예를 들어 --file이 단일 문자열 인자를 취하면, options.file은 사용자가 제공한 파일명이거나, 사용자가 해당 옵션을 제공하지 않으면 None입니다.

args, 옵션 구문 분석 후 남은 위치 인자 리스트

이 자습서 섹션에서는 가장 중요한 4가지 옵션 어트리뷰트만 다룹니다: action, type, dest (destination) 및 help만 다룹니다. 이 중, action이 가장 기본입니다.

옵션 액션의 이해

액션은 명령 줄에서 옵션을 발견할 때 수행 할 작업을 optparse에 알려줍니다. optparse에 하드 코딩된 고정된 액션 집합이 있습니다; 새로운 액션 추가는 섹션 optparse 확장하기에서 다루는 고급 주제입니다. 대부분의 액션은 optparse에게 어떤 변수에 값을 저장하도록 지시합니다—예를 들어, 명령 줄에서 문자열을 취해서 options의 어트리뷰트에 저장합니다.

옵션 액션을 지정하지 않으면, optparse의 기본값은 store입니다.

store 액션

가장 일반적인 옵션 액션은 store로, optparse에게 다음 인자(또는 현재 인자의 나머지)를 취하고, 올바른 형인지 확인한 다음, 선택한 대상에 저장하도록 지시합니다.

예를 들면:

parser.add_option("-f", "--file",
                  action="store", type="string", dest="filename")

이제 가짜 명령 줄을 만들고 optparse에게 구문 분석을 요청합시다:

args = ["-f", "foo.txt"]
(options, args) = parser.parse_args(args)

When optparse sees the option string -f, it consumes the next argument, foo.txt, and stores it in options.filename. So, after this call to parse_args(), options.filename is "foo.txt".

optparse에서 지원하는 다른 옵션 형은 int와 float입니다. 정수 인자를 기대하는 옵션은 다음과 같습니다:

parser.add_option("-n", type="int", dest="num")

이 옵션에는 긴 옵션 문자열이 없는데, 완벽하게 허용됩니다. 또한, 기본값이 store이기 때문에 명시적인 액션이 없습니다.

다른 가짜 명령 줄을 구문 분석해 봅시다. 이번에는, 옵션 인자를 옵션 바로 다음에 붙일 것입니다: -n42(하나의 인자)는 -n 42(두 개의 인자)와 동등하므로, 다음 코드는

(options, args) = parser.parse_args(["-n42"])
print(options.num)

42를 인쇄합니다.

형을 지정하지 않으면, optparse는 string을 가정합니다. 기본 액션이 store라는 사실과 결합하면, 첫 번째 예제를 훨씬 더 짧게 만들 수 있습니다:

parser.add_option("-f", "--file", dest="filename")

대상을 제공하지 않으면, optparse는 옵션 문자열에서 합리적인 기본값을 추측합니다: 첫 번째 긴 옵션 문자열이 --foo-bar이면 기본 대상은 foo_bar입니다. 긴 옵션 문자열이 없으면, optparse는 첫 번째 짧은 옵션 문자열을 찾습니다: -f의 기본 대상은 f입니다.

optparse는 내장 complex 형도 포함합니다. 형 추가는 섹션 optparse 확장하기에서 다룹니다.

불리언 (플래그) 옵션 처리하기

플래그 옵션(특정 옵션이 발견되면 변수를 참이나 거짓으로 설정합니다)은 매우 흔합니다. optparse는 store_true와 store_false의 두 가지 별도의 액션으로 지원합니다. 예를 들어, -v로 켜고 -q로 끄는 verbose 플래그가 있을 수 있습니다:

parser.add_option("-v", action="store_true", dest="verbose")
parser.add_option("-q", action="store_false", dest="verbose")

여기에 대상이 같은 두 가지 옵션이 있는데, 완벽하게 괜찮습니다. (단지 기본값을 설정할 때 약간 주의해야 함을 뜻합니다—아래를 참조하십시오.)

optparse가 명령 줄에서 -v를 만나면, options.verbose를 True로 설정합니다; -q를 만나면 options.verbose는 False로 설정됩니다.

다른 액션들

optparse에서 지원하는 다른 액션은 다음과 같습니다:

"store_const"

store a constant value, pre-set via Option.const

"append"

이 옵션의 인자를 리스트에 추가합니다

"count"

카운터를 1씩 증가시킵니다

"callback"

지정된 함수를 호출합니다

이들은 섹션 레퍼런스 지침서와 섹션 옵션 콜백에서 다룹니다.

기본값

위의 모든 예에는 특정 명령 줄 옵션을 볼 때 일부 변수 (“대상(destination)”) 설정이 수반됩니다. 이러한 옵션이 나타나지 않으면 어떻게 될까요? 기본값을 제공하지 않아서, 모두 None으로 설정됩니다. 이것은 일반적으로 괜찮지만, 때로는 더 많은 제어가 필요합니다. optparse는 각 대상에 대한 기본값을 제공할 수 있도록 하는데, 명령 줄이 구문 분석되기 전에 대입됩니다.

먼저, verbose/quiet 예를 고려하십시오. -q가 나타나지 않는 한 optparse가 verbose를 True로 설정하도록 하려면, 다음과 같이 할 수 있습니다:

parser.add_option("-v", action="store_true", dest="verbose", default=True)
parser.add_option("-q", action="store_false", dest="verbose")

기본값은 특정 옵션이 아닌 대상(destination)에 적용되고, 이 두 옵션은 같은 대상을 갖기 때문에, 다음과 정확히 동등합니다:

parser.add_option("-v", action="store_true", dest="verbose")
parser.add_option("-q", action="store_false", dest="verbose", default=True)

이걸 생각해봅시다:

parser.add_option("-v", action="store_true", dest="verbose", default=False)
parser.add_option("-q", action="store_false", dest="verbose", default=True)

다시, verbose의 기본값은 True입니다: 특정 대상에 대해 제공되는 마지막 기본값이 사용되는 값입니다.

A clearer way to specify default values is the set_defaults() method of OptionParser, which you can call at any time before calling parse_args():

parser.set_defaults(verbose=True)
parser.add_option(...)
(options, args) = parser.parse_args()

이전과 마찬가지로, 주어진 옵션 대상에 대해 지정된 마지막 값이 사용됩니다. 명확성을 위해, 둘 다가 아닌 한 가지 방법을 사용하여 기본값을 설정하십시오.

도움말 생성하기

도움말과 사용법 텍스트를 자동으로 생성하는 optparse의 기능은 사용자 친화적인 명령 줄 인터페이스를 만드는 데 유용합니다. 각 옵션에 대해 help 값을 제공하고, 선택적으로 전체 프로그램에 대한 짧은 사용법 메시지를 제공하기만 하면 됩니다. 다음은 사용자에게 친숙한 (문서화된) 옵션으로 채워진 OptionParser입니다:

usage = "usage: %prog [options] arg1 arg2"
parser = OptionParser(usage=usage)
parser.add_option("-v", "--verbose",
                  action="store_true", dest="verbose", default=True,
                  help="make lots of noise [default]")
parser.add_option("-q", "--quiet",
                  action="store_false", dest="verbose",
                  help="be vewwy quiet (I'm hunting wabbits)")
parser.add_option("-f", "--filename",
                  metavar="FILE", help="write output to FILE")
parser.add_option("-m", "--mode",
                  default="intermediate",
                  help="interaction mode: novice, intermediate, "
                       "or expert [default: %default]")

optparse가 명령 줄에서 -h나 --help를 만나거나, parser.print_help()를 호출하면, 다음을 표준 출력에 인쇄합니다:

Usage: <yourscript> [options] arg1 arg2

Options:
  -h, --help            show this help message and exit
  -v, --verbose         make lots of noise [default]
  -q, --quiet           be vewwy quiet (I'm hunting wabbits)
  -f FILE, --filename=FILE
                        write output to FILE
  -m MODE, --mode=MODE  interaction mode: novice, intermediate, or
                        expert [default: intermediate]

(도움말 출력이 help 옵션으로 트리거 되면, optparse가 도움말 텍스트를 인쇄한 후 종료합니다.)

여기에는 optparse가 최상의 도움말 메시지를 생성하는 데 도움이 되는 많은 것들이 있습니다:

스크립트는 자체 사용법 메시지를 정의합니다:

usage = "usage: %prog [options] arg1 arg2"

optparse는 사용법 문자열의 %prog를 현재 프로그램의 이름, 즉 os.path.basename(sys.argv[0])으로 확장합니다. 확장된 문자열은 자세한 옵션 도움말 앞에 인쇄됩니다.

사용법 문자열을 제공하지 않으면, optparse는 단순하지만, 합리적인 기본값을 사용합니다: "Usage: %prog [options]", 이는 스크립트가 위치 인자를 취하지 않는다면 괜찮습니다.

모든 옵션은 도움말 문자열을 정의하고, 줄 바꿈에 대해 걱정하지 않습니다—optparse는 줄 바꿈을 처리하고 도움말 출력을 보기 좋게 만듭니다.

options that take a value indicate this fact in their automatically generated help message, e.g. for the “mode” option:

-m MODE, --mode=MODE

Here, “MODE” is called the meta-variable: it stands for the argument that the user is expected to supply to -m/--mode. By default, optparse converts the destination variable name to uppercase and uses that for the meta-variable. Sometimes, that’s not what you want—for example, the --filename option explicitly sets metavar="FILE", resulting in this automatically generated option description:

-f FILE, --filename=FILE

이것은 공간을 절약하는 것 이상으로 중요합니다: 수동으로 작성된 도움말 텍스트는 메타 변수 FILE을 사용하여 반 형식 구문 -f FILE과 비형식적 의미 설명 “write output to FILE” 사이에 연결이 있다는 단서를 사용자에게 알려줍니다. 이는 최종 사용자에게 도움말 텍스트를 훨씬 더 명확하고 유용하게 만드는 간단하지만, 효과적인 방법입니다.

기본값이 있는 옵션은 도움말 문자열에 %default를 포함할 수 있습니다—optparse는 이를 옵션 기본값의 str()로 대체합니다. 옵션에 기본값이 없으면 (또는 기본값이 None이면), %default는 none으로 확장됩니다.

옵션 그룹화하기

많은 옵션을 다룰 때, 더 나은 도움말 출력을 위해 이러한 옵션을 그룹화하는 것이 편리합니다. OptionParser에는 여러 옵션 그룹이 포함될 수 있으며 각 그룹에는 여러 옵션이 포함될 수 있습니다.

옵션 그룹은 클래스 OptionGroup을 사용하여 얻습니다:

class optparse.OptionGroup(parser, title, description=None)

여기서

parser는 그룹이 삽입될 OptionParser 인스턴스입니다

title은 그룹 제목입니다

description(선택 사항)은 그룹에 대한 자세한 설명입니다

OptionGroup은 (OptionParser 처럼) OptionContainer에서 상속되므로 add_option() 메서드를 사용하여 그룹에 옵션을 추가할 수 있습니다.

일단 모든 옵션이 선언되면, OptionParser 메서드 add_option_group()을 사용하여 그룹이 이전에 정의된 구문 분석기에 추가됩니다.

이전 섹션에서 정의한 구문 분석기로 계속 진행하면, 구문 분석기에 OptionGroup을 쉽게 추가할 수 있습니다:

group = OptionGroup(parser, "Dangerous Options",
                    "Caution: use these options at your own risk.  "
                    "It is believed that some of them bite.")
group.add_option("-g", action="store_true", help="Group option.")
parser.add_option_group(group)

그러면 다음과 같은 도움말이 출력됩니다:

Usage: <yourscript> [options] arg1 arg2

Options:
  -h, --help            show this help message and exit
  -v, --verbose         make lots of noise [default]
  -q, --quiet           be vewwy quiet (I'm hunting wabbits)
  -f FILE, --filename=FILE
                        write output to FILE
  -m MODE, --mode=MODE  interaction mode: novice, intermediate, or
                        expert [default: intermediate]

  Dangerous Options:
    Caution: use these options at your own risk.  It is believed that some
    of them bite.

    -g                  Group option.

좀 더 완전한 예는 둘 이상의 그룹을 수반할 수 있습니다: 여전히 이전 예를 확장합니다:

group = OptionGroup(parser, "Dangerous Options",
                    "Caution: use these options at your own risk.  "
                    "It is believed that some of them bite.")
group.add_option("-g", action="store_true", help="Group option.")
parser.add_option_group(group)

group = OptionGroup(parser, "Debug Options")
group.add_option("-d", "--debug", action="store_true",
                 help="Print debug information")
group.add_option("-s", "--sql", action="store_true",
                 help="Print all SQL statements executed")
group.add_option("-e", action="store_true", help="Print every action done")
parser.add_option_group(group)

다음과 같은 출력을 줍니다:

Usage: <yourscript> [options] arg1 arg2

Options:
  -h, --help            show this help message and exit
  -v, --verbose         make lots of noise [default]
  -q, --quiet           be vewwy quiet (I'm hunting wabbits)
  -f FILE, --filename=FILE
                        write output to FILE
  -m MODE, --mode=MODE  interaction mode: novice, intermediate, or expert
                        [default: intermediate]

  Dangerous Options:
    Caution: use these options at your own risk.  It is believed that some
    of them bite.

    -g                  Group option.

  Debug Options:
    -d, --debug         Print debug information
    -s, --sql           Print all SQL statements executed
    -e                  Print every action done

특히 옵션 그룹을 프로그래밍 방식으로 작업할 때, 또 다른 흥미로운 메서드는 다음과 같습니다:

OptionParser.get_option_group(opt_str)

짧거나 긴 옵션 문자열 opt_str(예를 들어 '-o'나 '--option')이 속한 OptionGroup을 반환합니다. 그러한 OptionGroup이 없으면, None을 반환합니다.

버전 문자열 인쇄하기

간단한 사용법 문자열과 유사하게, optparse는 프로그램의 버전 문자열을 인쇄 할 수도 있습니다. OptionParser에 version 인자로 문자열을 제공해야 합니다:

parser = OptionParser(usage="%prog [-f] [-q]", version="%prog 1.0")

%prog는 usage에서처럼 확장됩니다. 그 외에도, version은 원하는 무엇이든 포함할 수 있습니다. 이를 제공하면, optparse는 자동으로 구문 분석기에 --version 옵션을 추가합니다. 명령 줄에서 이 옵션을 발견하면, (%prog를 대체하여) version 문자열을 확장하고, stdout에 인쇄한 다음, 종료합니다.

예를 들어, 스크립트가 /usr/bin/foo로 호출되면:

$ /usr/bin/foo --version
foo 1.0

다음 두 가지 메서드를 사용하여 version 문자열을 인쇄하고 가져올 수 있습니다:

OptionParser.print_version(file=None)

현재 프로그램의 버전 메시지(self.version)를 file(기본값은 표준 출력)로 인쇄합니다. print_usage()와 마찬가지로, self.version에 등장하는 %prog는 현재 프로그램의 이름으로 대체됩니다. self.version이 비어 있거나 정의되지 않았으면 아무 작업도 수행하지 않습니다.

OptionParser.get_version()

print_version()과 같지만 인쇄하는 대신 버전 문자열을 반환합니다.

optparse가 에러를 처리하는 방법

optparse가 걱정해야 할 에러에는 두 가지가 있습니다: 프로그래머 에러와 사용자 에러. 프로그래머 에러는 일반적으로 OptionParser.add_option()에 대한 잘못된 호출입니다, 예를 들어 잘못된 옵션 문자열, 알 수 없는 옵션 어트리뷰트, 누락된 옵션 어트리뷰트 등. 이러한 에러는 일반적인 방식으로 처리됩니다: 예외(optparse.OptionError나 TypeError)를 발생시키고 프로그램이 충돌하도록 합니다.

사용자 에러를 처리하는 것은 훨씬 더 중요합니다, 코드가 아무리 안정적이더라도 발생하는 것이 보장되기 때문입니다. optparse는 잘못된 옵션 인자 (-n이 정수 인자를 취할 때 -n 4x 전달), 누락된 인자(-n이 모든 형의 인자를 취할 때, 명령 줄 끝의 -n)와 같은 일부 사용자 에러를 자동으로 감지할 수 있습니다. 또한, OptionParser.error()를 호출하여 응용 프로그램 정의 에러 조건을 알릴 수 있습니다:

(options, args) = parser.parse_args()
...
if options.a and options.b:
    parser.error("options -a and -b are mutually exclusive")

두 경우 모두, optparse는 같은 방식으로 에러를 처리합니다: 프로그램의 사용법 메시지와 에러 메시지를 표준 에러에 인쇄하고 에러 상태 2로 종료합니다.

사용자가 정수를 취하는 옵션에 4x를 전달하는 위의 첫 번째 예를 고려하십시오:

$ /usr/bin/foo -n 4x
Usage: foo [options]

foo: error: option -n: invalid integer value: '4x'

또는 사용자가 값을 전혀 전달하지 못하는 경우:

$ /usr/bin/foo -n
Usage: foo [options]

foo: error: -n option requires an argument

optparse-생성 에러 메시지는 항상 에러와 관련된 옵션을 언급하도록 주의를 기울입니다; 응용 프로그램 코드에서 OptionParser.error()를 호출할 때도 그래야 합니다.

optparse의 기본 에러 처리 동작이 여러분의 요구에 맞지 않으면, OptionParser를 서브 클래스 화하고 exit() 및/또는 error() 메서드를 재정의해야 합니다.

모두 합치기

일반적으로 optparse 기반 스크립트는 다음과 같습니다:

from optparse import OptionParser
...
def main():
    usage = "usage: %prog [options] arg"
    parser = OptionParser(usage)
    parser.add_option("-f", "--file", dest="filename",
                      help="read data from FILENAME")
    parser.add_option("-v", "--verbose",
                      action="store_true", dest="verbose")
    parser.add_option("-q", "--quiet",
                      action="store_false", dest="verbose")
    ...
    (options, args) = parser.parse_args()
    if len(args) != 1:
        parser.error("incorrect number of arguments")
    if options.verbose:
        print("reading %s..." % options.filename)
    ...

if __name__ == "__main__":
    main()

레퍼런스 지침서

구문 분석기 만들기

optparse를 사용하는 첫 번째 단계는 OptionParser 인스턴스를 만드는 것입니다.

class optparse.OptionParser(...)

OptionParser 생성자에는 필수 인자가 없지만, 여러 선택적 키워드 인자가 있습니다. 이들을 항상 키워드 인자로 전달해야 합니다, 즉, 인자가 선언된 순서에 의존하지 마십시오.

usage (기본값: "%prog [options]")

The usage summary to print when your program is run incorrectly or with a help option. When optparse prints the usage string, it expands %prog to os.path.basename(sys.argv[0]) (or to prog if you passed that keyword argument). To suppress a usage message, pass the special value optparse.SUPPRESS_USAGE.

option_list (기본값: [])

구문 분석기를 채울 Option 객체 리스트. option_list의 옵션은 standard_option_list(OptionParser 서브 클래스에서 설정할 수 있는 클래스 어트리뷰트)의 모든 옵션 뒤에 추가되지만, 모든 버전(version) 또는 도움말(help) 옵션 앞에 추가됩니다. 폐지되었습니다; 대신 구문 분석기를 만든 후 add_option()을 사용하십시오.

option_class (기본값: optparse.Option)

add_option()에서 구문 분석기에 옵션을 추가할 때 사용할 클래스.

version (기본값: None)

사용자가 버전(version) 옵션을 제공할 때 인쇄 할 버전 문자열. version에 참값을 제공하면, optparse는 단일 옵션 문자열 --version으로 버전 옵션을 자동으로 추가합니다. 하위 문자열 %prog는 usage와 마찬가지로 확장됩니다.

conflict_handler (기본값: "error")

충돌하는 옵션 문자열이 있는 옵션이 구문 분석기에 추가될 때 수행 할 작업을 지정합니다; 섹션 옵션 간의 충돌을 참조하십시오.

description (기본값: None)

프로그램에 대한 간략한 개요를 제공하는 텍스트 단락. optparse는 현재 터미널 너비에 맞게 이 단락을 다시 포맷하고 사용자가 도움말을 요청할 때 인쇄합니다 (usage 이후, 옵션 목록 이전).

formatter (기본값: 새 IndentedHelpFormatter)

도움말 텍스트를 인쇄하는 데 사용될 optparse.HelpFormatter의 인스턴스. optparse는 이 목적으로 두 개의 구상 클래스를 제공합니다: IndentedHelpFormatter 와 TitledHelpFormatter.

add_help_option (기본값: True)

참이면, optparse는 구문 분석기에 도움말 옵션(옵션 문자열 -h와 --help)을 추가합니다.

prog

usage와 version에서 %prog를 확장할 때 os.path.basename(sys.argv[0]) 대신 사용할 문자열.

epilog (기본값: None)

옵션 도움말 다음에 인쇄할 도움말 텍스트 단락.

구문 분석기 채우기

구문 분석기를 옵션으로 채우는 방법에는 여러 가지가 있습니다. 선호되는 방법은 섹션 자습서에 표시된 대로, OptionParser.add_option()을 사용하는 것입니다. add_option()은 다음 두 가지 방법의 하나로 호출 할 수 있습니다:

(make_option()에서 반환되는 것과 같은) Option 인스턴스를 전달합니다

make_option()(즉, Option 생성자)에 허용되는 위치와 키워드 인자의 조합을 전달합니다, 그러면 Option 인스턴스를 만듭니다

다른 대안은 다음과 같이 미리 생성된 Option 인스턴스 리스트를 OptionParser 생성자에 전달하는 것입니다:

option_list = [
    make_option("-f", "--filename",
                action="store", type="string", dest="filename"),
    make_option("-q", "--quiet",
                action="store_false", dest="verbose"),
    ]
parser = OptionParser(option_list=option_list)

(make_option()은 Option 인스턴스를 만들기 위한 팩토리 함수입니다; 현재는 Option 생성자의 별칭입니다. optparse의 향후 버전은 Option을 여러 클래스로 나눌 수 있으며, make_option()은 인스턴스 화할 올바른 클래스를 선택할 것입니다. Option을 직접 인스턴스 화하지 마십시오.)

옵션 정의하기

각 Option 인스턴스는 동의어 명령 줄 옵션 문자열 집합을 나타냅니다, 예를 들어 -f와 --file. 짧거나 긴 옵션 문자열을 얼마든지 지정할 수 있지만, 전체적으로 옵션 문자열을 적어도 하나 지정해야 합니다.

Option 인스턴스를 만드는 규범적 방법은 OptionParser의 add_option() 메서드를 사용하는 것입니다.

OptionParser.add_option(option)

OptionParser.add_option(*opt_str, attr=value, ...)

짧은 옵션 문자열로만 옵션을 정의하려면:

parser.add_option("-f", attr=value, ...)

그리고 긴 옵션 문자열로만 옵션을 정의하려면:

parser.add_option("--foo", attr=value, ...)

키워드 인자는 새 Option 객체의 어트리뷰트를 정의합니다. 가장 중요한 옵션 어트리뷰트는 action이며, 전체적으로 어떤 어트리뷰트가 관련성이 있거나 필요한지를 결정합니다. 관련 없는 옵션 어트리뷰트를 전달하거나, 필수 어트리뷰트를 전달하지 못하면, optparse는 실수를 설명하는 OptionError 예외를 발생시킵니다.

옵션의 action은 명령 줄에서 이 옵션을 만날 때 optparse가 수행하는 작업을 결정합니다. optparse에 하드 코딩된 표준 옵션 액션은 다음과 같습니다:

"store"

이 옵션의 인자를 저장합니다 (기본값)

"store_const"

store a constant value, pre-set via Option.const

"store_true"

True를 저장합니다

"store_false"

False를 저장합니다

"append"

이 옵션의 인자를 리스트에 추가합니다

"append_const"

append a constant value to a list, pre-set via Option.const

"count"

카운터를 1씩 증가시킵니다

"callback"

지정된 함수를 호출합니다

"help"

모든 옵션과 해당 설명을 포함하는 사용법 메시지를 인쇄합니다

(액션을 제공하지 않으면, 기본값은 "store"입니다. 이 액션의 경우, type과 dest 옵션 어트리뷰트도 제공할 수 있습니다; 표준 옵션 액션을 참조하십시오.)

As you can see, most actions involve storing or updating a value somewhere. optparse always creates a special object for this, conventionally called options, which is an instance of optparse.Values.

class optparse.Values

An object holding parsed argument names and values as attributes. Normally created by calling when calling OptionParser.parse_args(), and can be overridden by a custom subclass passed to the values argument of OptionParser.parse_args() (as described in 인자 구문 분석하기).

Option arguments (and various other values) are stored as attributes of this object, according to the dest (destination) option attribute.

예를 들어, 다음과 같이 호출할 때

parser.parse_args()

optparse가 하는 첫 번째 작업 중 하나는 options 객체를 만드는 것입니다:

options = Values()

이 구문 분석기의 옵션 중 하나가 다음과 같이 정의되었으면:

parser.add_option("-f", "--file", action="store", type="string", dest="filename")

그리고 구문 분석 중인 명령 줄에는 다음 중 하나가 포함되면:

-ffoo
-f foo
--file=foo
--file foo

optparse는 이 옵션을 볼 때 다음과 동등한 일을 합니다

options.filename = "foo"

type과 dest 옵션 어트리뷰트는 action만큼 중요하지만, action은 모든 옵션에 적합한 유일한 어트리뷰트입니다.

옵션 어트리뷰트

class optparse.Option

A single command line argument, with various attributes passed by keyword to the constructor. Normally created with OptionParser.add_option() rather than directly, and can be overridden by a custom class via the option_class argument to OptionParser.

다음 옵션 어트리뷰트는 OptionParser.add_option()에 키워드 인자로 전달될 수 있습니다. 특정 옵션과 관련이 없는 옵션 어트리뷰트를 전달하거나, 필수 옵션 어트리뷰트를 전달하지 못하면 optparse는 OptionError를 발생시킵니다.

Option.action

(기본값: "store")

이 옵션이 명령 줄에서 보일 때 optparse의 동작을 결정합니다; 사용 가능한 옵션은 여기에 설명되어 있습니다.

Option.type

(기본값: "string")

이 옵션이 기대하는 인자 형 (예를 들어, "string"이나 "int"); 사용 가능한 옵션 형은 여기에 설명되어 있습니다.

Option.dest

(기본값: 옵션 문자열에서 파생됩니다)

옵션의 액션이 어딘가에 값을 쓰거나 수정하는 것을 의미하면, 이것은 optparse에게 어디에 쓸 것인지 알려줍니다: dest는 명령 줄을 구문 분석할 때 optparse가 빌드하는 options 객체의 어트리뷰트의 이름을 정합니다.

Option.default

옵션이 명령 줄에서 보이지 않으면 이 옵션의 대상에 사용할 값. OptionParser.set_defaults()도 참조하십시오.

Option.nargs

(기본값: 1)

이 옵션이 보일 때 소비되어야 하는 type 형의 인자 수입니다. > 1 이면, optparse는 값의 튜플을 dest에 저장합니다.

Option.const

상숫값을 저장하는 액션의 경우, 저장할 상숫값.

Option.choices

"choice" 형 옵션의 경우, 사용자가 이 중에서 선택할 수 있는 문자열 리스트.

Option.callback

액션 "callback"이 있는 옵션의 경우, 이 옵션이 보일 때 호출 할 콜러블. 콜러블에 전달된 인자에 대한 자세한 내용은 섹션 옵션 콜백을 참조하십시오.

Option.callback_args

Option.callback_kwargs

4개의 표준 콜백 인자 다음에 callback에 전달할 추가 위치와 키워드 인자.

Option.help

Help text to print for this option when listing all available options after the user supplies a help option (such as --help). If no help text is supplied, the option will be listed without help text. To hide this option, use the special value optparse.SUPPRESS_HELP.

Option.metavar

(기본값: 옵션 문자열에서 파생됩니다)

도움말 텍스트를 인쇄할 때 사용할 옵션 인자를 나타냅니다. 예제는 섹션 자습서를 참조하십시오.

표준 옵션 액션

다양한 옵션 액션은 모두 요구 사항과 효과가 약간 다릅니다. 대부분의 액션에는 optparse의 동작을 안내하기 위해 지정할 수 있는 몇 가지 연관된 옵션 어트리뷰트가 있습니다; 일부는 해당 액션을 사용하는 모든 옵션에 대해 지정해야 하는 필수 어트리뷰트가 있습니다.

"store" [연관된 옵션: type, dest, nargs, choices]

옵션 뒤에 인자가 와야 하며, 인자는 type에 따라 값으로 변환되고, dest에 저장됩니다. nargs > 1 이면, 명령 줄에서 여러 인자가 소비됩니다; 모두 type에 따라 변환되고 dest에 튜플로 저장됩니다. 표준 옵션 형 섹션을 참조하십시오.

choices가 제공되면 (문자열 리스트나 튜플), 형의 기본값은 "choice"입니다.

type이 제공되지 않으면, 기본값은 "string"입니다.

dest가 제공되지 않으면, optparse는 첫 번째 긴 옵션 문자열에서 대상을 파생합니다 (예를 들어, --foo-bar는 foo_bar를 암시합니다). 긴 옵션 문자열이 없으면, optparse는 첫 번째 짧은 옵션 문자열에서 대상을 파생합니다 (예를 들어, -f는 f를 암시합니다).

예:

parser.add_option("-f")
parser.add_option("-p", type="float", nargs=3, dest="point")

다음과 같은 명령 줄을 구문 분석할 때

-f foo.txt -p 1 -3.5 4 -fbar.txt

optparse는 다음과 같이 설정합니다

options.f = "foo.txt"
options.point = (1.0, -3.5, 4.0)
options.f = "bar.txt"

"store_const" [필수 옵션: const; 연관된 옵션: dest]

값 const는 dest에 저장됩니다.

예:

parser.add_option("-q", "--quiet",
                  action="store_const", const=0, dest="verbose")
parser.add_option("-v", "--verbose",
                  action="store_const", const=1, dest="verbose")
parser.add_option("--noisy",
                  action="store_const", const=2, dest="verbose")

--noisy가 보이면, optparse는 다음과 같이 설정합니다

options.verbose = 2

"store_true" [연관된 옵션: dest]

True를 dest에 저장하는 "store_const"의 특별한 경우.

"store_false" [연관된 옵션: dest]

"store_true"와 비슷하지만, False를 저장합니다.

예:

parser.add_option("--clobber", action="store_true", dest="clobber")
parser.add_option("--no-clobber", action="store_false", dest="clobber")

"append" [연관된 옵션: type, dest, nargs, choices]

옵션 다음에는 dest의 리스트에 추가되는 인자가 와야 합니다. dest의 기본값이 제공되지 않으면, optparse가 명령 줄에서 이 옵션을 처음 발견할 때 빈 리스트가 자동으로 만들어집니다. nargs > 1 이면, 여러 인자가 소비되며, nargs 길이의 튜플이 dest에 추가됩니다.

type과 dest의 기본값은 "store" 액션의 경우와 같습니다.

예:

parser.add_option("-t", "--tracks", action="append", type="int")

-t3가 명령 줄에 보이면, optparse는 다음과 동등한 것을 수행합니다:

options.tracks = []
options.tracks.append(int("3"))

잠시 후, --tracks=4가 보이면, 다음을 수행합니다:

options.tracks.append(int("4"))

append 액션은 옵션의 현재 값에 대해 append 메서드를 호출합니다. 이는 지정된 모든 기본값에 append 메서드가 있어야 함을 의미합니다. 또한, 기본값이 비어 있지 않으면, 기본 요소가 옵션의 구문 분석된 값에 존재하며, 명령 줄의 모든 값이 기본값 뒤에 추가됨을 의미합니다:

>>> parser.add_option("--files", action="append", default=['~/.mypkg/defaults'])
>>> opts, args = parser.parse_args(['--files', 'overrides.mypkg'])
>>> opts.files
['~/.mypkg/defaults', 'overrides.mypkg']

"append_const" [필수 옵션: const; 연관된 옵션: dest]

"store_const"와 비슷하지만, const 값이 dest에 추가됩니다; "append"와 마찬가지로, dest의 기본값은 None이며, 옵션이 처음 발견될 때 빈 리스트가 자동으로 만들어집니다.

"count" [연관된 옵션: dest]

dest에 저장된 정수를 증가시킵니다. 기본값이 제공되지 않으면, dest는 처음으로 증가하기 전에 0으로 설정됩니다.

예:

parser.add_option("-v", action="count", dest="verbosity")

-v가 명령 줄에서 처음 보이면, optparse는 다음과 동등한 작업을 수행합니다:

options.verbosity = 0
options.verbosity += 1

이후에 -v가 나타날 때마다 다음과 같이 합니다

options.verbosity += 1

"callback" [필수 옵션: callback; 연관된 옵션: type, nargs, callback_args, callback_kwargs]

callback으로 지정된 함수를 호출합니다, 이 함수는 다음과 같이 호출됩니다

func(option, opt_str, value, parser, *args, **kwargs)

자세한 내용은 섹션 옵션 콜백을 참조하십시오.

"help"

현재 옵션 구문 분석기의 모든 옵션에 대한 전체 도움말 메시지를 인쇄합니다. 도움말 메시지는 OptionParser의 생성자에 전달된 usage 문자열과 모든 옵션에 전달된 help 문자열로 구성됩니다.

If no help string is supplied for an option, it will still be listed in the help message. To omit an option entirely, use the special value optparse.SUPPRESS_HELP.

optparse는 모든 OptionParser에 help 옵션을 자동으로 추가하므로, 일반적으로 만들 필요가 없습니다.

예:

from optparse import OptionParser, SUPPRESS_HELP

# usually, a help option is added automatically, but that can
# be suppressed using the add_help_option argument
parser = OptionParser(add_help_option=False)

parser.add_option("-h", "--help", action="help")
parser.add_option("-v", action="store_true", dest="verbose",
                  help="Be moderately verbose")
parser.add_option("--file", dest="filename",
                  help="Input file to read data from")
parser.add_option("--secret", help=SUPPRESS_HELP)

optparse가 명령 줄에서 -h나 --help를 보면, 다음 도움말 메시지와 같은 내용을 stdout에 인쇄합니다 (sys.argv[0]이 "foo.py"라고 가정합니다):

Usage: foo.py [options]

Options:
  -h, --help        Show this help message and exit
  -v                Be moderately verbose
  --file=FILENAME   Input file to read data from

도움말 메시지를 인쇄한 후, optparse는 sys.exit(0)으로 프로세스를 종료합니다.

"version"

OptionParser에 제공된 버전 번호를 stdout에 인쇄하고 종료합니다. 버전 번호는 실제로 OptionParser의 print_version() 메서드에 의해 포맷되고 인쇄됩니다. 일반적으로 version 인자가 OptionParser 생성자에 제공되는 경우에만 의미가 있습니다. help 옵션과 마찬가지로, optparse는 필요할 때 자동으로 추가하기 때문에, version 옵션을 거의 만들지 않습니다.

표준 옵션 형

optparse에는 다섯 가지 내장 옵션 형이 있습니다: "string", "int", "choice", "float" 및 "complex". 새로운 옵션 형을 추가해야 하면, 섹션 optparse 확장하기를 참조하십시오.

문자열 옵션에 대한 인자는 어떤 방식으로도 검사되거나 변환되지 않습니다: 명령 줄의 텍스트는 있는 그대로 대상에 저장(또는 콜백에 전달)됩니다.

정수 인자("int" 형)는 다음과 같이 구문 분석됩니다:

숫자가 0x로 시작하면, 16진수로 구문 분석됩니다

숫자가 0으로 시작하면, 8진수로 구문 분석됩니다

숫자가 0b로 시작하면, 이진수로 구문 분석됩니다

그렇지 않으면, 숫자는 10진수로 구문 분석됩니다

변환은 적절한 진수(2, 8, 10 또는 16)로 int()를 호출하여 수행됩니다. 이것이 실패하면, 더 유용한 에러 메시지를 제공하기는 하지만, optparse도 마찬가지로 실패합니다.

"float"와 "complex" 옵션 인자는 유사한 에러 처리로 float()와 complex()로 직접 변환됩니다.

"choice" 옵션은 "string" 옵션의 서브 형입니다. choices 옵션 어트리뷰트(문자열 시퀀스)는 허용되는 옵션 인자 집합을 정의합니다. optparse.check_choice()는 사용자가 제공한 옵션 인자를 이 마스터 리스트와 비교하고 유효하지 않은 문자열이 주어지면 OptionValueError 를 발생시킵니다.

인자 구문 분석하기

The whole point of creating and populating an OptionParser is to call its parse_args() method.

OptionParser.parse_args(args=None, values=None)

Parse the command-line options found in args.

The input parameters are

args

처리할 인자의 리스트 (기본값: sys.argv[1:])

values

a Values object to store option arguments in (default: a new instance of Values) – if you give an existing object, the option defaults will not be initialized on it

and the return value is a pair (options, args) where

options

the same object that was passed in as values, or the optparse.Values instance created by optparse

args

모든 옵션이 처리된 후 남은 위치 인자

The most common usage is to supply neither keyword argument. If you supply values, it will be modified with repeated setattr() calls (roughly one for every option argument stored to an option destination) and returned by parse_args().

If parse_args() encounters any errors in the argument list, it calls the OptionParser’s error() method with an appropriate end-user error message. This ultimately terminates your process with an exit status of 2 (the traditional Unix exit status for command-line errors).

옵션 구문 분석기를 조회하고 조작하기

옵션 구문 분석기의 기본 동작은 약간 사용자 정의 할 수 있으며, 옵션 구문 분석기를 들여다보고 거기에 무엇이 있는지 볼 수도 있습니다. OptionParser는 다음과 같은 몇 가지 메서드를 제공합니다:

OptionParser.disable_interspersed_args()

첫 번째 옵션이 아닌 것에서 중지하도록 구문 분석을 설정합니다. 예를 들어 -a와 -b가 모두 인자를 취하지 않는 간단한 옵션이면, optparse는 일반적으로 다음 문법을 허용합니다:

prog -a arg1 -b arg2

그리고 다음과 동등하게 취급합니다

prog -a -b arg1 arg2

이 기능을 비활성화하려면, disable_interspersed_args()를 호출하십시오. 이렇게 하면 옵션 구문 분석이 첫 번째 옵션이 아닌 인자에서 중지되는, 전통적인 유닉스 문법이 복원됩니다.

자체 옵션이 있는 다른 명령을 실행하는 명령 프로세서가 있고 이러한 옵션이 혼동되지 않도록 하려면 이것을 사용하십시오. 예를 들어, 각 명령에는 다른 옵션 집합이 있을 수 있습니다.

OptionParser.enable_interspersed_args()

첫 번째 옵션이 아닌 것에서 구문 분석이 중지되지 않도록 설정하여, 명령 인자와 스위치를 분산시킬 수 있도록 합니다. 이것이 기본 동작입니다.

OptionParser.get_option(opt_str)

옵션 문자열 opt_str을 갖는 Option 인스턴스를 반환합니다, 또는 해당 옵션 문자열을 갖는 옵션이 없으면 None을 반환합니다.

OptionParser.has_option(opt_str)

OptionParser에 옵션 문자열 opt_str을 갖는 옵션이 있으면 True를 반환합니다 (예를 들어, -q나 --verbose).

OptionParser.remove_option(opt_str)

OptionParser에 opt_str에 해당하는 옵션이 있으면, 해당 옵션이 제거됩니다. 해당 옵션이 다른 옵션 문자열을 제공하면, 해당 옵션 문자열은 모두 유효하지 않게 됩니다. 이 OptionParser에 속하는 옵션에서 opt_str이 등장하지 않으면, ValueError를 발생시킵니다.

옵션 간의 충돌

주의하지 않으면, 충돌하는 옵션 문자열을 갖는 옵션을 정의하기 쉽습니다:

parser.add_option("-n", "--dry-run", ...)
...
parser.add_option("-n", "--noisy", ...)

(일부 표준 옵션을 사용하여 자체 OptionParser 서브 클래스를 정의한 경우 특히 그렇습니다.)

옵션을 추가할 때마다, optparse는 기존 옵션과의 충돌을 확인합니다. 발견되면, 현재 충돌 처리 메커니즘을 호출합니다. 충돌 처리 메커니즘을 설정할 수 있는데, 생성자에서:

parser = OptionParser(..., conflict_handler=handler)

또는 별도의 호출로 가능합니다:

parser.set_conflict_handler(handler)

사용 가능한 충돌 처리기는 다음과 같습니다:

"error" (기본값)

옵션 충돌이 프로그래밍 에러라고 가정하고 OptionConflictError 를 발생시킵니다

"resolve"

옵션 충돌을 지능적으로 해결합니다 (아래를 참조하십시오)

예를 들어, 충돌을 지능적으로 해결하고 OptionParser를 정의하고 충돌하는 옵션을 추가해 보겠습니다:

parser = OptionParser(conflict_handler="resolve")
parser.add_option("-n", "--dry-run", ..., help="do no harm")
parser.add_option("-n", "--noisy", ..., help="be noisy")

At this point, optparse detects that a previously added option is already using the -n option string. Since conflict_handler is "resolve", it resolves the situation by removing -n from the earlier option’s list of option strings. Now --dry-run is the only way for the user to activate that option. If the user asks for help, the help message will reflect that:

Options:
  --dry-run     do no harm
  ...
  -n, --noisy   be noisy

It’s possible to whittle away the option strings for a previously added option until there are none left, and the user has no way of invoking that option from the command-line. In that case, optparse removes that option completely, so it doesn’t show up in help text or anywhere else. Carrying on with our existing OptionParser:

parser.add_option("--dry-run", ..., help="new dry-run option")

이 시점에서, 원래 -n/--dry-run 옵션에 더는 액세스할 수 없어서, optparse는 해당 옵션을 제거하고, 다음 도움말 텍스트를 남깁니다:

Options:
  ...
  -n, --noisy   be noisy
  --dry-run     new dry-run option

정리

OptionParser 인스턴스에는 여러 순환 참조가 있습니다. 이것은 파이썬의 가비지 수거기에선 문제가 되지 않지만, 작업이 끝나면 OptionParser에서 destroy()를 호출하여 순환 참조를 명시적으로 끊을 수 있습니다. 이것은 OptionParser에서 큰 객체 그래프에 도달할 수 있는 장기 실행 응용 프로그램에서 특히 유용합니다.

기타 메서드

OptionParser는 몇 가지 다른 공용 메서드를 지원합니다:

OptionParser.set_usage(usage)

Set the usage string according to the rules described above for the usage constructor keyword argument. Passing None sets the default usage string; use optparse.SUPPRESS_USAGE to suppress a usage message.

OptionParser.print_usage(file=None)

현재 프로그램의 사용법 메시지(self.usage)를 file(기본값 stdout)로 인쇄합니다. self.usage에 등장하는 문자열 %prog는 현재 프로그램의 이름으로 대체됩니다. self.usage가 비어 있거나 정의되지 않았으면 아무 작업도 수행하지 않습니다.

OptionParser.get_usage()

print_usage()와 같지만 인쇄하는 대신 사용법 문자열을 반환합니다.

OptionParser.set_defaults(dest=value, ...)

한 번에 여러 옵션 대상에 대한 기본값을 설정합니다. 여러 옵션이 같은 대상을 공유 할 수 있기 때문에, set_defaults()를 사용하여 옵션의 기본값을 설정하는 것이 좋습니다. 예를 들어, 여러 “mode” 옵션이 모두 같은 대상을 설정하면, 그중 하나가 기본값을 설정할 수 있으며 마지막 옵션이 이깁니다:

parser.add_option("--advanced", action="store_const",
                  dest="mode", const="advanced",
                  default="novice")    # overridden below
parser.add_option("--novice", action="store_const",
                  dest="mode", const="novice",
                  default="advanced")  # overrides above setting

이러한 혼동을 피하려면, set_defaults()를 사용하십시오:

parser.set_defaults(mode="advanced")
parser.add_option("--advanced", action="store_const",
                  dest="mode", const="advanced")
parser.add_option("--novice", action="store_const",
                  dest="mode", const="novice")

옵션 콜백

optparse의 내장 액션과 형이 여러분의 필요에 충분하지 않으면, 두 가지 선택이 있습니다: optparse를 확장하거나 콜백 옵션을 정의합니다. optparse를 확장하는 것이 더 일반적이지만, 많은 간단한 경우에는 과합니다. 종종 간단한 콜백만 있으면 됩니다.

콜백 옵션을 정의하는 두 단계가 있습니다:

"callback" 액션을 사용하여 옵션 자체를 정의합니다

콜백을 작성합니다; 이것은 아래에 설명된 대로, 최소한 4개의 인자를 취하는 함수(또는 메서드)입니다

콜백 옵션 정의하기

항상 그렇듯이, 콜백 옵션을 정의하는 가장 쉬운 방법은 OptionParser.add_option() 메서드를 사용하는 것입니다. action과 별도로 지정해야 하는 유일한 옵션 어트리뷰트는 호출할 함수인 callback입니다:

parser.add_option("-c", action="callback", callback=my_callback)

callback은 함수(또는 다른 콜러블 객체)이므로, 이 콜백 옵션을 만들 때 my_callback()을 이미 정의했어야 합니다. 이 간단한 경우, optparse는 -c가 인자를 취하는지조차 알지 못합니다. 이는 일반적으로 옵션이 인자를 받지 않음을 의미합니다—명령 줄에 -c가 있다는 것만 알 필요가 있습니다. 그러나 일부 상황에서는, 콜백이 임의의 수의 명령 줄 인자를 소비하도록 할 수 있습니다. 콜백 작성이 까다로워지는 곳입니다: 이 섹션의 뒷부분에서 다룹니다.

optparse는 항상 4개의 특정 인자를 콜백에 전달하며, callback_args와 callback_kwargs를 통해 지정하는 경우에만 추가 인자를 전달합니다. 따라서 최소 콜백 함수 서명은 다음과 같습니다:

def my_callback(option, opt, value, parser):

콜백에 대한 네 가지 인자가 아래에 설명되어 있습니다.

콜백 옵션을 정의할 때 제공할 수 있는 몇 가지 다른 옵션 어트리뷰트가 있습니다:

type

일반적인 의미를 갖습니다: "store"나 "append" 액션과 마찬가지로, optparse에게 하나의 인자를 소비하고 이를 type으로 변환하도록 지시합니다. 그러나 optparse는 변환된 값을 어딘가에 저장하는 대신 콜백 함수에 전달합니다.

nargs

역시 일반적인 의미를 갖습니다: 제공되고 > 1 이면, optparse는 nargs 인자를 소비하며 각 인자는 type으로 변환 가능해야 합니다. 그런 다음 변환된 값의 튜플을 콜백에 전달합니다.

callback_args

콜백에 전달할 추가 위치 인자의 튜플

callback_kwargs

콜백에 전달할 추가 키워드 인자의 딕셔너리

콜백이 호출되는 방법

모든 콜백은 다음과 같이 호출됩니다:

func(option, opt_str, value, parser, *args, **kwargs)

여기서

option

콜백을 호출하는 Option 인스턴스입니다

opt_str

콜백을 트리거 하는 명령 줄에 나타나는 옵션 문자열입니다. (축약된 긴 옵션이 사용되면, opt_str은 완전한, 규범적인 옵션 문자열이 됩니다—예를 들어 사용자가 --foobar의 약어로 명령 줄에 --foo를 입력하면, opt_str은 "--foobar"가 됩니다.)

value

명령 줄에 나타난 이 옵션에 대한 인자입니다. optparse는 type이 설정되었을 때만 인자를 기대합니다; value의 형은 옵션의 형이 암시하는 형입니다. 이 옵션의 type이 None(기대하는 인자 없음)이면, value는 None이 됩니다. nargs > 1 이면, value는 적절한 형의 값의 튜플이 됩니다.

parser

모든 것을 구동하는 OptionParser 인스턴스입니다, 인스턴스 어트리뷰트를 통해 다른 흥미로운 데이터에 액세스 할 수 있어서 주로 유용합니다:

parser.largs

the current list of leftover arguments, ie. arguments that have been consumed but are neither options nor option arguments. Feel free to modify parser.largs, e.g. by adding more arguments to it. (This list will become args, the second return value of parse_args().)

parser.rargs

나머지 인자의 현재 리스트, 즉, opt_str과 value(해당한다면)가 제거되고, 그 뒤에 오는 인자만 그대로 남아 있습니다. 예를 들어 더 많은 인자를 소비하여, parser.rargs를 자유롭게 수정하십시오.

parser.values

옵션값이 기본적으로 저장되는 객체 (optparse.OptionValues의 인스턴스). 이를 통해 콜백은 옵션값을 저장하기 위해 나머지 optparse와 같은 메커니즘을 사용할 수 있습니다; 전역이나 클로저를 엉망으로 만들 필요가 없습니다. 명령 줄에서 이미 발견된 모든 옵션의 값에 액세스하거나 수정할 수도 있습니다.

args

callback_args 옵션 어트리뷰트를 통해 제공되는 임의의 위치 인자의 튜플입니다.

kwargs

callback_kwargs를 통해 제공된 임의의 키워드 인자의 딕셔너리입니다.

콜백에서 에러 발생시키기

옵션이나 인자에 문제가 있으면 콜백 함수는 OptionValueError 를 발생시켜야 합니다. optparse는 이것을 포착하고 프로그램을 종료하고, stderr에 여러분이 제공하는 에러 메시지를 인쇄합니다. 메시지는 명확하고 간결하며 정확해야 하며 잘못된 옵션을 언급해야 합니다. 그렇지 않으면, 사용자는 자신이 무엇을 잘못했는지 파악하는 데 어려움을 겪을 것입니다.

콜백 예제 1: 간단한 콜백

다음은 인자를 취하지 않고, 단순히 옵션이 발견되었음을 기록하는 콜백 옵션의 예입니다:

def record_foo_seen(option, opt_str, value, parser):
    parser.values.saw_foo = True

parser.add_option("--foo", action="callback", callback=record_foo_seen)

물론 "store_true" 액션으로 그렇게 할 수 있습니다.

콜백 예제 2: 옵션 순서 확인

여기에 약간 더 흥미로운 예가 있습니다: -a가 발견되었다는 사실을 기록하지만, 명령 줄에서 -b 뒤에 오면 폭발합니다.

def check_order(option, opt_str, value, parser):
    if parser.values.b:
        raise OptionValueError("can't use -a after -b")
    parser.values.a = 1
...
parser.add_option("-a", action="callback", callback=check_order)
parser.add_option("-b", action="store_true", dest="b")

콜백 예제 3: 옵션 순서 확인 (일반화)

If you want to reuse this callback for several similar options (set a flag, but blow up if -b has already been seen), it needs a bit of work: the error message and the flag that it sets must be generalized.

def check_order(option, opt_str, value, parser):
    if parser.values.b:
        raise OptionValueError("can't use %s after -b" % opt_str)
    setattr(parser.values, option.dest, 1)
...
parser.add_option("-a", action="callback", callback=check_order, dest='a')
parser.add_option("-b", action="store_true", dest="b")
parser.add_option("-c", action="callback", callback=check_order, dest='c')

콜백 예제 4: 임의 조건 확인

물론, 여기에 어떤 조건도 넣을 수 있습니다—이미 정의된 옵션의 값을 확인하는 데 국한되지 않습니다. 예를 들어, 만월일 때 호출해서는 안 되는 옵션이 있으면, 다음과 같이 하면 됩니다:

def check_moon(option, opt_str, value, parser):
    if is_moon_full():
        raise OptionValueError("%s option invalid when moon is full"
                               % opt_str)
    setattr(parser.values, option.dest, 1)
...
parser.add_option("--foo",
                  action="callback", callback=check_moon, dest="foo")

(is_moon_full()의 정의는 독자를 위한 연습 문제로 남겨 둡니다.)

콜백 예제 5: 고정 인자

고정된 수의 인자를 사용하는 콜백 옵션을 정의하면 상황이 약간 더 흥미로워집니다. 콜백 옵션이 인자를 받도록 지정하는 것은 "store"나 "append" 옵션을 정의하는 것과 유사합니다: type을 정의하면, 옵션은 해당 형으로 변환 할 수 있어야 하는 하나의 인자를 취합니다; nargs를 추가로 정의하면, 옵션은 nargs 인자를 취합니다.

다음은 표준 "store" 액션을 흉내 내는 예입니다:

def store_value(option, opt_str, value, parser):
    setattr(parser.values, option.dest, value)
...
parser.add_option("--foo",
                  action="callback", callback=store_value,
                  type="int", nargs=3, dest="foo")

optparse가 3개의 인자를 소비하고 이를 정수로 변환하는 작업을 처리함에 유의하십시오; 여러분이 해야 할 일은 그것들을 저장하는 것뿐입니다. (또는 무엇이든; 분명히 이 예제에서는 콜백이 필요하지 않습니다.)

콜백 예제 6: 가변 인자

가변적인 수의 인자를 취하는 옵션을 원할 때 상황이 복잡해집니다. 이 경우, optparse는 이것을 위한 내장 기능을 제공하지 않아서 콜백을 작성해야 합니다. 그리고 optparse가 일반적으로 처리하는 전통적인 유닉스 명령 줄 구문 분석의 복잡한 문제를 여러분이 처리해야 합니다. 특히, 콜백은 날(bare) --와 - 인자에 대한 전통적인 규칙을 구현해야 합니다:

--나 -는 옵션 인자가 될 수 있습니다

날 -- (어떤 옵션에 대한 인자가 아닌 경우): 명령 줄 처리를 중단하고 --를 버립니다

날 - (어떤 옵션에 대한 인자가 아닌 경우): 명령 줄 처리를 중지하지만 -는 유지합니다 (parser.largs에 추가합니다)

가변적인 수의 인자를 취하는 옵션을 원한다면, 몇 가지 미묘하고 까다로운 문제가 있습니다. 여러분이 선택하는 정확한 구현은 여러분이 여러분의 응용 프로그램을 위해 취하고자 하는 절충을 기반으로 할 것입니다 (이것이 optparse가 이런 종류의 것을 직접 지원하지 않는 이유입니다).

그런데도, 가변 인자가 있는 옵션에 대한 콜백에는 가시가 있습니다:

def vararg_callback(option, opt_str, value, parser):
    assert value is None
    value = []

    def floatable(str):
        try:
            float(str)
            return True
        except ValueError:
            return False

    for arg in parser.rargs:
        # stop on --foo like options
        if arg[:2] == "--" and len(arg) > 2:
            break
        # stop on -a, but not on -3 or -3.0
        if arg[:1] == "-" and len(arg) > 1 and not floatable(arg):
            break
        value.append(arg)

    del parser.rargs[:len(value)]
    setattr(parser.values, option.dest, value)

...
parser.add_option("-c", "--callback", dest="vararg_attr",
                  action="callback", callback=vararg_callback)

optparse 확장하기

optparse가 명령 줄 옵션을 해석하는 방법의 두 가지 주요 제어 요소는 각 옵션의 액션과 형이므로, 확장 방향은 새 액션과 새 형을 추가하는 것입니다.

새로운 형 추가하기

새로운 형을 추가하려면, optparse의 Option 클래스의 여러분 자신의 서브 클래스를 정의해야 합니다. 이 클래스에는 optparse의 형을 정의하는 몇 가지 어트리뷰트가 있습니다: TYPES와 TYPE_CHECKER.

Option.TYPES

형 이름의 튜플; 여러분의 서브 클래스에서, 표준 튜플을 기반으로 하는 새 튜플 TYPES를 정의하십시오.

Option.TYPE_CHECKER

형 이름을 형 검사 함수에 매핑하는 딕셔너리. 형 검사 함수는 다음과 같은 서명을 갖습니다:

def check_mytype(option, opt, value)

여기서 option은 Option 인스턴스이고, opt는 옵션 문자열(예를 들어, -f)이며, value는 검사되고 원하는 형으로 변환되어야 하는 명령 줄의 문자열입니다. check_mytype()은 가상의 형 mytype의 객체를 반환해야 합니다. 형 검사 함수가 반환한 값은 OptionParser.parse_args()에서 반환한 OptionValues 인스턴스에 포함되거나 value 매개 변수로 콜백에 전달됩니다.

형 검사 함수는 문제가 발생하면 OptionValueError 를 발생시켜야 합니다. OptionValueError 는 OptionParser의 error() 메서드에 있는 그대로 전달되는 단일 문자열 인자를 취하며, 이는 차례로 프로그램 이름과 문자열 "error:"를 앞에 붙이고 프로세스를 종료하기 전에 모든 것을 stderr에 인쇄합니다.

다음은 명령 줄에서 파이썬 스타일 복소수를 구문 분석하기 위해 "complex" 옵션 형을 추가하는 것을 보여주는 우스꽝스러운 예입니다. (optparse 1.3은 복소수에 대한 기본 지원을 추가했기 때문에 전보다 훨씬 우스꽝스럽지만, 신경 쓰지 마십시오.)

첫째, 필요한 임포트:

from copy import copy
from optparse import Option, OptionValueError

나중에 (Option 서브 클래스의 TYPE_CHECKER 클래스 어트리뷰트에서) 참조되므로, 형 검사기를 먼저 정의해야 합니다:

def check_complex(option, opt, value):
    try:
        return complex(value)
    except ValueError:
        raise OptionValueError(
            "option %s: invalid complex value: %r" % (opt, value))

마지막으로, Option 서브 클래스:

class MyOption (Option):
    TYPES = Option.TYPES + ("complex",)
    TYPE_CHECKER = copy(Option.TYPE_CHECKER)
    TYPE_CHECKER["complex"] = check_complex

(Option.TYPE_CHECKER의 copy()를 만들지 않았다면, optparse의 Option 클래스의 TYPE_CHECKER 어트리뷰트를 수정하게 될 것입니다. 이것은 파이썬이기 때문에, 좋은 태도와 상식을 제외하고는 아무것도 이렇게 하는 것을 막을 수 없습니다.)

이것이 전부입니다! 이제 OptionParser가 Option 대신 MyOption을 사용하도록 지시해야 한다는 점을 제외하고는, 다른 optparse 기반 스크립트와 마찬가지로 새 옵션 형을 사용하는 스크립트를 작성할 수 있습니다:

parser = OptionParser(option_class=MyOption)
parser.add_option("-c", type="complex")

또는, 여러분 자신만의 옵션 목록을 만들어 OptionParser에 전달할 수 있습니다; 위의 방법으로 add_option()을 사용하지 않으면, OptionParser에 사용할 옵션 클래스를 알려줄 필요가 없습니다:

option_list = [MyOption("-c", action="store", type="complex", dest="c")]
parser = OptionParser(option_list=option_list)

새로운 액션 추가하기

optparse에는 액션에 대한 몇 가지 분류가 있음을 이해해야 해서, 새 액션을 추가하는 것은 약간 까다롭습니다:

“저장” 액션

optparse가 현재 OptionValues 인스턴스의 어트리뷰트에 값을 저장하는 결과를 주는 액션; 이러한 옵션을 사용하려면 Option 생성자에 dest 어트리뷰트를 제공해야 합니다.

“형이 있는” 액션

명령 줄에서 값을 취하고 이것이 특정 형일 것으로 기대하는 액션; 또는, 특정 형으로 변환할 수 있는 문자열. 이러한 옵션을 사용하려면 Option 생성자에 type 어트리뷰트를 제공해야 합니다.

이들은 겹치는 집합입니다: 일부 기본 “저장” 액션은 "store", "store_const", "append" 및 "count"이고, 기본 “형이 있는” 액션은 "store", "append" 및 "callback"입니다.

액션을 추가할 때, Option의 다음 클래스 어트리뷰트 중 하나 이상에 나열하여 분류해야 합니다 (모두 문자열 리스트입니다):

Option.ACTIONS

모든 액션은 ACTIONS에 나열되어야 합니다.

Option.STORE_ACTIONS

“저장” 액션이 여기에 추가로 나열됩니다.

Option.TYPED_ACTIONS

“형이 있는” 액션이 여기에 추가로 나열됩니다.

Option.ALWAYS_TYPED_ACTIONS

항상 형을 취하는 액션(즉, 옵션이 항상 값을 취하는 액션)이 여기에 추가로 나열됩니다. 이것의 유일한 효과는 optparse가 ALWAYS_TYPED_ACTIONS에 액션이 나열되는 명시적인 형이 없는 옵션에 기본형인 "string"을 대입한다는 것입니다.

새 액션을 실제로 구현하려면, Option의 take_action() 메서드를 재정의하고 액션을 인식하는 케이스를 추가해야 합니다.

예를 들어, "extend" 액션을 추가해 보겠습니다. 이것은 표준 "append" 액션과 유사하지만, 명령 줄에서 단일 값을 취해서 기존 리스트에 추가하는 대신, "extend"는 단일 쉼표로 구분된 문자열에서 여러 값을 취해서 기존 리스트를 확장합니다. 즉, --names가 "string" 형의 "extend" 옵션이면, 다음과 같은 명령 줄은

--names=foo,bar --names blah --names ding,dong

다음과 같은 리스트를 만듭니다

["foo", "bar", "blah", "ding", "dong"]

다시 Option의 서브 클래스를 정의합니다:

class MyOption(Option):

    ACTIONS = Option.ACTIONS + ("extend",)
    STORE_ACTIONS = Option.STORE_ACTIONS + ("extend",)
    TYPED_ACTIONS = Option.TYPED_ACTIONS + ("extend",)
    ALWAYS_TYPED_ACTIONS = Option.ALWAYS_TYPED_ACTIONS + ("extend",)

    def take_action(self, action, dest, opt, value, values, parser):
        if action == "extend":
            lvalue = value.split(",")
            values.ensure_value(dest, []).extend(lvalue)
        else:
            Option.take_action(
                self, action, dest, opt, value, values, parser)

참고할만한 특징:

"extend"는 명령 줄에서 값을 기대하기도 하고 그 값을 어딘가에 저장하기도 하므로, STORE_ACTIONS와 TYPED_ACTIONS 모두에 들어갑니다.

optparse가 기본형 "string"을 "extend" 액션에 대입하도록 하기 위해, ALWAYS_TYPED_ACTIONS에도 "extend" 액션을 넣습니다.

MyOption.take_action()은 이 하나의 새로운 액션만 구현하고, 표준 optparse 액션을 위해 제어를 Option.take_action()으로 되돌립니다.

values는 매우 유용한 ensure_value() 메서드를 제공하는 optparse_parser.Values 클래스의 인스턴스입니다. ensure_value()는 본질적으로 안전밸브가 있는 getattr()입니다; 다음과 같이 호출됩니다

values.ensure_value(attr, value)

If the attr attribute of values doesn’t exist or is None, then ensure_value() first sets it to value, and then returns value. This is very handy for actions like "extend", "append", and "count", all of which accumulate data in a variable and expect that variable to be of a certain type (a list for the first two, an integer for the latter). Using ensure_value() means that scripts using your action don’t have to worry about setting a default value for the option destinations in question; they can just leave the default as None and ensure_value() will take care of getting it right when it’s needed.

Exceptions

exception optparse.OptionError

Raised if an Option instance is created with invalid or inconsistent arguments.

exception optparse.OptionConflictError

Raised if conflicting options are added to an OptionParser.

exception optparse.OptionValueError

Raised if an invalid option value is encountered on the command line.

exception optparse.BadOptionError

Raised if an invalid option is passed on the command line.

exception optparse.AmbiguousOptionError

Raised if an ambiguous option is passed on the command line.

Removed Modules

The modules described in this chapter have been removed from the Python standard library. They are documented here to help people find replacements.

aifc — Read and write AIFF and AIFC files

asynchat — Asynchronous socket command/response handler

asyncore — Asynchronous socket handler

audioop — Manipulate raw audio data

cgi — Common Gateway Interface support

cgitb — Traceback manager for CGI scripts

chunk — Read IFF chunked data

crypt — Function to check Unix passwords

distutils — Building and installing Python modules

imghdr — Determine the type of an image

imp — Access the import internals

mailcap — Mailcap file handling

msilib — Read and write Microsoft Installer files

nis — Interface to Sun’s NIS (Yellow Pages)

nntplib — NNTP protocol client

ossaudiodev — Access to OSS-compatible audio devices

pipes — Interface to shell pipelines

smtpd — SMTP Server

sndhdr — Determine type of sound file

spwd — The shadow password database

sunau — Read and write Sun AU files

telnetlib — Telnet client

uu — Encode and decode uuencode files

xdrlib — Encode and decode XDR data

Security Considerations

The following modules have specific security considerations:

base64: base64 security considerations in RFC 4648 [https://datatracker.ietf.org/doc/html/rfc4648.html]

hashlib: all constructors take a “usedforsecurity” keyword-only argument disabling known insecure and blocked algorithms

http.server is not suitable for production use, only implementing basic security checks. See the security considerations.

logging: Logging configuration uses eval()

multiprocessing: Connection.recv() uses pickle

pickle: Restricting globals in pickle

random shouldn’t be used for security purposes, use secrets instead

shelve: shelve is based on pickle and thus unsuitable for dealing with untrusted sources

ssl: SSL/TLS security considerations

subprocess: Subprocess security considerations

tempfile: mktemp is deprecated due to vulnerability to race conditions

xml: XML vulnerabilities

zipfile: maliciously prepared .zip files can cause disk volume exhaustion

The -I command line option can be used to run Python in isolated mode. When it cannot be used, the -P option or the PYTHONSAFEPATH environment variable can be used to not prepend a potentially unsafe path to sys.path such as the current directory, the script’s directory or an empty string.

파이썬 인터프리터 확장 및 내장

이 문서는 새로운 모듈로 파이썬 인터프리터를 확장하기 위해 C 나 C++로 모듈을 작성하는 방법을 설명합니다. 이러한 모듈은 새로운 함수뿐만 아니라 새로운 객체 형과 메서드를 정의할 수 있습니다. 또한, 확장 언어로 사용하기 위해, 파이썬 인터프리터를 다른 응용 프로그램에 내장시키는 방법에 관해서도 설명합니다. 마지막으로, 하부 운영 체제에서 이 기능을 지원하는 경우, 동적으로 (실행시간에) 인터프리터에 로드될 수 있도록 확장 모듈을 컴파일하고 링크하는 방법을 보여줍니다.

이 문서는 파이썬에 대한 기본 지식을 전제로 합니다. 언어에 대한 형식적이지 않은 소개는 파이썬 자습서 를 보십시오. 파이썬 언어 레퍼런스 는 보다 형식적인 언어 정의를 제공합니다. 파이썬 표준 라이브러리 는 존재하는 객체 형, 함수 및 모듈(내장된 것과 파이썬으로 작성된 것 모두)을 설명하는데, 이것들이 언어의 응용 범위를 넓힙니다.

전체 파이썬/C API에 대한 자세한 설명은 별도의 파이썬/C API 레퍼런스 설명서 를 참조하십시오.

권장 제삼자 도구

This guide only covers the basic tools for creating extensions provided as part of this version of CPython. Third party tools like Cython [https://cython.org/], cffi [https://cffi.readthedocs.io], SWIG [https://www.swig.org] and Numba [https://numba.pydata.org/] offer both simpler and more sophisticated approaches to creating C and C++ extensions for Python.

더 보기

파이썬 패키징 사용자 지침서: 바이너리 확장 [https://packaging.python.org/guides/packaging-binary-extensions/]

파이썬 패키징 사용자 지침서는 바이너리 확장의 생성을 단순화하는 몇 가지 사용 가능한 도구를 다루고 있을 뿐만 아니라, 확장 모듈을 만드는 것이 왜 바람직한지 여러 가지 이유에 대해서도 논의합니다.

제삼자 도구 없이 확장 만들기

지침서의 이 부문에서는 제삼자 도구의 도움 없이 C와 C++ 확장을 만드는 방법에 관해 설명합니다. 여러분 자신의 C 확장을 만드는 데 권장되는 방법이라기보다는, 주로 도구를 제작하는 사람들을 대상으로 합니다.

1. C나 C++로 파이썬 확장하기

1.1. 간단한 예

1.2. 막간극: 에러와 예외

1.3. 예제로 돌아가기

1.4. 모듈의 메서드 테이블과 초기화 함수

1.5. 컴파일과 링크

1.6. C에서 파이썬 함수 호출하기

1.7. 확장 함수에서 매개 변수 추출하기

1.8. 확장 함수를 위한 키워드 매개 변수

1.9. 임의의 값을 구축하기

1.10. 참조 횟수

1.11. C++로 확장 작성하기

1.12. 확장 모듈을 위한 C API 제공하기

2. 확장형 정의하기: 자습서

2.1. 기초

2.2. 기초 예제에 데이터와 메서드 추가하기

2.3. 데이터 어트리뷰트를 더 세밀하게 제어하기

2.4. 순환 가비지 수거 지원하기

2.5. 다른 형의 서브 클래싱

3. 확장형 정의하기: 여러 가지 주제

3.1. 파이널리제이션과 할당 해제

3.2. 객체 표현

3.3. 어트리뷰트 관리

3.4. 객체 비교

3.5. 추상 프로토콜 지원

3.6. 약한 참조 지원

3.7. 추가 제안

4. C와 C++ 확장 빌드하기

4.1. Building C and C++ Extensions with setuptools

5. 윈도우에서 C와 C++ 확장 빌드하기

5.1. 요리책 접근법

5.2. 유닉스와 윈도우의 차이점

5.3. DLL을 실제로 사용하기

더 큰 응용 프로그램에 CPython 런타임을 내장하기

때로는, 파이썬 인터프리터를 메인 응용 프로그램으로 사용하고 그 안에서 실행되는 확장을 만드는 대신, CPython 런타임을 더 큰 응용 프로그램에 내장하는 것이 바람직합니다. 이 절에서는 이를 성공적으로 수행하는 데 관련된 몇 가지 세부 사항에 관해 설명합니다.

1. 다른 응용 프로그램에 파이썬 내장하기

1.1. 매우 고수준의 내장

1.2. 매우 고수준 내장을 넘어서: 개요

1.3. 순수한 내장

1.4. 내장된 파이썬을 확장하기

1.5. C++로 파이썬 내장하기

1.6. 유닉스 계열 시스템에서 컴파일과 링크하기

1. C나 C++로 파이썬 확장하기

C로 프로그래밍하는 방법을 알고 있다면, 파이썬에 새로운 내장 모듈을 추가하기는 매우 쉽습니다. 그러한 확장 모듈(extension modules)은 파이썬에서 직접 할 수 없는 두 가지 일을 할 수 있습니다: 새로운 내장 객체 형을 구현할 수 있고, C 라이브러리 함수와 시스템 호출을 호출할 수 있습니다.

확장을 지원하기 위해, 파이썬 API(Application Programmers Interface)는 파이썬 런타임 시스템의 대부분 측면에 액세스 할 수 있는 함수, 매크로 및 변수 집합을 정의합니다. 파이썬 API는 헤더 "Python.h"를 포함해 C 소스 파일에 통합됩니다.

확장 모듈의 컴파일은 시스템 설정뿐만 아니라 의도하는 용도에 따라 다릅니다; 자세한 내용은 다음 장에서 설명합니다.

참고

C 확장 인터페이스는 CPython에만 해당하며, 확장 모듈은 다른 파이썬 구현에서는 작동하지 않습니다. 많은 경우에, C 확장을 작성하지 않고 다른 구현으로의 이식성을 유지하는 것이 가능합니다. 예를 들어, 사용 사례가 C 라이브러리 함수나 시스템 호출을 호출하는 것이라면, 사용자 정의 C 코드를 작성하는 대신 ctypes 모듈이나 cffi [https://cffi.readthedocs.io/] 라이브러리 사용을 고려해야 합니다. 이 모듈을 사용하면 C 코드와 인터페이스 하기 위한 파이썬 코드를 작성할 수 있으며 C 확장 모듈을 작성하고 컴파일하는 것보다 파이썬 구현 간에 이식성이 더 좋습니다.

1.1. 간단한 예

spam(몬티 파이썬 팬들이 가장 좋아하는 음식…)이라는 확장 모듈을 만듭시다, 그리고 C 라이브러리 함수 system()에 대한 파이썬 인터페이스를 만들고 싶다고 합시다 [1]. 이 함수는 널 종료 문자열을 인자로 취하고 정수를 반환합니다. 우리는 이 함수를 다음과 같이 파이썬에서 호출할 수 있기를 원합니다:

>>> import spam
>>> status = spam.system("ls -l")

spammodule.c 파일을 만드는 것으로 시작하십시오. (역사적으로, 모듈을 spam이라고 하면, 해당 구현을 포함하는 C 파일은 spammodule.c라고 합니다; 모듈 이름이 spammify처럼 매우 길면, 모듈 이름은 그냥 spammify.c일 수 있습니다.)

파일의 처음 두 줄은 다음과 같습니다:

#define PY_SSIZE_T_CLEAN
#include <Python.h>

이것은 파이썬 API를 가져옵니다 (원한다면 모듈의 목적과 저작권 표시를 설명하는 주석을 추가할 수 있습니다).

참고

파이썬이 일부 시스템의 표준 헤더에 영향을 미치는 일부 전처리기 정의를 정의할 수 있어서, 표준 헤더가 포함되기 전에 반드시 Python.h를 포함해야 합니다.

#define PY_SSIZE_T_CLEAN was used to indicate that Py_ssize_t should be used in some APIs instead of int. It is not necessary since Python 3.13, but we keep it here for backward compatibility. See 문자열과 버퍼 for a description of this macro.

Python.h가 정의한 사용자가 볼 수 있는 기호는 표준 헤더 파일에 정의된 기호를 제외하고 모두 Py나 PY 접두사를 갖습니다. 편의를 위해, 그리고 파이썬 인터프리터가 광범위하게 사용하기 때문에, "Python.h"는 몇 가지 표준 헤더 파일을 포함합니다: <stdio.h>, <string.h>, <errno.h> 및 <stdlib.h>. 후자의 헤더 파일이 시스템에 없으면, 함수 malloc(), free() 및 realloc()을 직접 선언합니다.

다음으로 모듈 파일에 추가하는 것은 파이썬 표현식 spam.system(string)이 평가될 때 호출될 C 함수입니다 (이것이 어떻게 호출되는지 곧 보게 될 것입니다):

static PyObject *
spam_system(PyObject *self, PyObject *args)
{
    const char *command;
    int sts;

    if (!PyArg_ParseTuple(args, "s", &command))
        return NULL;
    sts = system(command);
    return PyLong_FromLong(sts);
}

파이썬의 인자 목록(예를 들어, 단일 표현식 "ls -l")에서 C 함수로 전달되는 인자로의 간단한 변환이 있습니다. C 함수에는 항상 self와 args라는 두 개의 인자가 있습니다.

self 인자는 모듈 수준 함수에서 모듈 객체를 가리킵니다; 메서드의 경우 객체 인스턴스를 가리킵니다.

args 인자는 인자를 포함하는 파이썬 튜플 객체에 대한 포인터입니다. 튜플의 각 항목은 호출의 인자 목록에 있는 인자에 해당합니다. 인자는 파이썬 객체입니다 — C 함수에서 무언가를 수행하려면 이들을 C 값으로 변환해야 합니다. 파이썬 API의 PyArg_ParseTuple() 함수는 인자 형을 확인하고 C 값으로 변환합니다. 템플릿 문자열을 사용하여 필요한 인자 형과 변환된 값을 저장할 C 변수 형을 결정합니다. 나중에 이것에 대해 자세히 알아보겠습니다.

모든 인자의 형이 올바르고 해당 구성 요소가 주소가 전달된 변수에 저장되면, PyArg_ParseTuple()은 참(0이 아닙니다)을 반환합니다. 유효하지 않은 인자 목록이 전달되면 거짓(0)을 반환합니다. 후자의 경우 호출 함수가 (예에서 보듯이) NULL을 즉시 반환할 수 있도록 적절한 예외를 발생시킵니다.

1.2. 막간극: 에러와 예외

An important convention throughout the Python interpreter is the following: when a function fails, it should set an exception condition and return an error value (usually -1 or a NULL pointer). Exception information is stored in three members of the interpreter’s thread state. These are NULL if there is no exception. Otherwise they are the C equivalents of the members of the Python tuple returned by sys.exc_info(). These are the exception type, exception instance, and a traceback object. It is important to know about them to understand how errors are passed around.

파이썬 API는 다양한 형의 예외를 설정하기 위한 여러 함수를 정의합니다.

가장 일반적인 것은 PyErr_SetString()입니다. 인자는 예외 객체와 C 문자열입니다. 예외 객체는 보통 PyExc_ZeroDivisionError와 같은 미리 정의된 객체입니다. C 문자열은 에러의 원인을 나타내며 파이썬 문자열 객체로 변환되어 예외의 “연관된 값”으로 저장됩니다.

또 다른 유용한 함수는 PyErr_SetFromErrno()입니다. 이 함수는 예외 인자만 취하고 전역 변수 errno를 검사하여 관련 값을 구성합니다. 가장 일반적인 함수는 PyErr_SetObject()이며, 예외와 관련 값인 두 개의 객체 인자를 취합니다. 이러한 함수들에 전달되는 객체를 Py_INCREF() 할 필요는 없습니다.

PyErr_Occurred()로 예외가 설정되어 있는지 비 파괴적으로 검사할 수 있습니다. 현재 예외 객체나 예외가 발생하지 않았으면 NULL을 반환합니다. 반환 값에서 알 수 있어야 해서 일반적으로 함수 호출에서 에러가 발생했는지 확인하기 위해 PyErr_Occurred()를 호출할 필요는 없습니다.

When a function f that calls another function g detects that the latter fails, f should itself return an error value (usually NULL or -1). It should not call one of the PyErr_* functions — one has already been called by g. f’s caller is then supposed to also return an error indication to its caller, again without calling PyErr_*, and so on — the most detailed cause of the error was already reported by the function that first detected it. Once the error reaches the Python interpreter’s main loop, this aborts the currently executing Python code and tries to find an exception handler specified by the Python programmer.

(There are situations where a module can actually give a more detailed error message by calling another PyErr_* function, and in such cases it is fine to do so. As a general rule, however, this is not necessary, and can cause information about the cause of the error to be lost: most operations can fail for a variety of reasons.)

실패한 함수 호출로 설정된 예외를 무시하려면, PyErr_Clear()를 호출하여 예외 조건을 명시적으로 지워야 합니다. C 코드가 PyErr_Clear()를 호출해야 하는 유일한 때는 에러를 인터프리터에 전달하지 않고 스스로 완전히 처리하려고 하는 경우입니다 (아마 다른 것을 시도하거나, 아무것도 잘못되지 않은 척해서).

모든 실패한 malloc() 호출은 예외로 전환되어야 합니다 — malloc()(또는 realloc())의 직접 호출자는 스스로 PyErr_NoMemory()를 호출하고 실패 표시기를 반환해야 합니다. 모든 객체 생성 함수(예를 들어, PyLong_FromLong())는 이미 이 작업을 수행하므로, 이 주의는 malloc()을 직접 호출하는 호출자에게만 해당합니다.

또한 PyArg_ParseTuple()과 그 친구들의 중요한 예외를 제외하고, 정수 상태를 반환하는 함수는 유닉스 시스템 호출처럼 일반적으로 성공 시 양수 값이나 0을 반환하고, 실패 시 -1을 반환합니다.

마지막으로, 에러 표시기를 반환할 때 (이미 만든 객체를 Py_XDECREF()나 Py_DECREF()를 호출하여) 가비지를 정리하십시오!

The choice of which exception to raise is entirely yours. There are predeclared C objects corresponding to all built-in Python exceptions, such as PyExc_ZeroDivisionError, which you can use directly. Of course, you should choose exceptions wisely — don’t use PyExc_TypeError to mean that a file couldn’t be opened (that should probably be PyExc_OSError). If something’s wrong with the argument list, the PyArg_ParseTuple() function usually raises PyExc_TypeError. If you have an argument whose value must be in a particular range or must satisfy other conditions, PyExc_ValueError is appropriate.

모듈에 고유한 새 예외를 정의할 수도 있습니다. 이를 위해, 일반적으로 파일 시작 부분에 정적 객체 변수를 선언합니다:

static PyObject *SpamError;

and initialize it in your module’s initialization function (PyInit_spam()) with an exception object:

PyMODINIT_FUNC
PyInit_spam(void)
{
    PyObject *m;

    m = PyModule_Create(&spammodule);
    if (m == NULL)
        return NULL;

    SpamError = PyErr_NewException("spam.error", NULL, NULL);
    if (PyModule_AddObjectRef(m, "error", SpamError) < 0) {
        Py_CLEAR(SpamError);
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

Note that the Python name for the exception object is spam.error. The PyErr_NewException() function may create a class with the base class being Exception (unless another class is passed in instead of NULL), described in 내장 예외.

Note also that the SpamError variable retains a reference to the newly created exception class; this is intentional! Since the exception could be removed from the module by external code, an owned reference to the class is needed to ensure that it will not be discarded, causing SpamError to become a dangling pointer. Should it become a dangling pointer, C code which raises the exception could cause a core dump or other unintended side effects.

We discuss the use of PyMODINIT_FUNC as a function return type later in this sample.

The spam.error exception can be raised in your extension module using a call to PyErr_SetString() as shown below:

static PyObject *
spam_system(PyObject *self, PyObject *args)
{
    const char *command;
    int sts;

    if (!PyArg_ParseTuple(args, "s", &command))
        return NULL;
    sts = system(command);
    if (sts < 0) {
        PyErr_SetString(SpamError, "System command failed");
        return NULL;
    }
    return PyLong_FromLong(sts);
}

1.3. 예제로 돌아가기

예제 함수로 돌아가서, 이제 여러분은 이 문장을 이해할 수 있어야 합니다:

if (!PyArg_ParseTuple(args, "s", &command))
    return NULL;

It returns NULL (the error indicator for functions returning object pointers) if an error is detected in the argument list, relying on the exception set by PyArg_ParseTuple(). Otherwise the string value of the argument has been copied to the local variable command. This is a pointer assignment and you are not supposed to modify the string to which it points (so in Standard C, the variable command should properly be declared as const char *command).

다음 문장은 유닉스 함수 system()을 호출인데, PyArg_ParseTuple()에서 얻은 문자열을 전달합니다:

sts = system(command);

Our spam.system() function must return the value of sts as a Python object. This is done using the function PyLong_FromLong().

return PyLong_FromLong(sts);

이 경우, 정수 객체를 반환합니다. (예, 정수조차도 파이썬에서는 힙 상의 객체입니다!)

If you have a C function that returns no useful argument (a function returning void), the corresponding Python function must return None. You need this idiom to do so (which is implemented by the Py_RETURN_NONE macro):

Py_INCREF(Py_None);
return Py_None;

Py_None은 특수 파이썬 객체 None의 C 이름입니다. 앞에서 보았듯이, 대부분의 상황에서 “에러”를 뜻하는 NULL 포인터가 아니라 진짜 파이썬 객체입니다.

1.4. 모듈의 메서드 테이블과 초기화 함수

I promised to show how spam_system() is called from Python programs. First, we need to list its name and address in a “method table”:

static PyMethodDef SpamMethods[] = {
    ...
    {"system",  spam_system, METH_VARARGS,
     "Execute a shell command."},
    ...
    {NULL, NULL, 0, NULL}        /* Sentinel */
};

세 번째 항목 (METH_VARARGS)에 유의하십시오. 이것은 인터프리터에게 C 함수에 사용될 호출 규칙을 알려주는 플래그입니다. 일반적으로 항상 METH_VARARGS나 METH_VARARGS | METH_KEYWORDS여야 합니다; 0 값은 더는 사용되지 않는 PyArg_ParseTuple() 변형이 사용됨을 의미합니다.

METH_VARARGS 만 사용할 때, 함수는 파이썬 수준 매개 변수가 PyArg_ParseTuple()을 통한 구문 분석에 허용되는 튜플로 전달될 것으로 기대해야 합니다; 이 함수에 대한 자세한 정보는 아래에 제공됩니다.

The METH_KEYWORDS bit may be set in the third field if keyword arguments should be passed to the function. In this case, the C function should accept a third PyObject * parameter which will be a dictionary of keywords. Use PyArg_ParseTupleAndKeywords() to parse the arguments to such a function.

메서드 테이블은 모듈 정의 구조체에서 참조되어야 합니다:

static struct PyModuleDef spammodule = {
    PyModuleDef_HEAD_INIT,
    "spam",   /* name of module */
    spam_doc, /* module documentation, may be NULL */
    -1,       /* size of per-interpreter state of the module,
                 or -1 if the module keeps state in global variables. */
    SpamMethods
};

This structure, in turn, must be passed to the interpreter in the module’s initialization function. The initialization function must be named PyInit_name(), where name is the name of the module, and should be the only non-static item defined in the module file:

PyMODINIT_FUNC
PyInit_spam(void)
{
    return PyModule_Create(&spammodule);
}

Note that PyMODINIT_FUNC declares the function as PyObject * return type, declares any special linkage declarations required by the platform, and for C++ declares the function as extern "C".

When the Python program imports module spam for the first time, PyInit_spam() is called. (See below for comments about embedding Python.) It calls PyModule_Create(), which returns a module object, and inserts built-in function objects into the newly created module based upon the table (an array of PyMethodDef structures) found in the module definition. PyModule_Create() returns a pointer to the module object that it creates. It may abort with a fatal error for certain errors, or return NULL if the module could not be initialized satisfactorily. The init function must return the module object to its caller, so that it then gets inserted into sys.modules.

When embedding Python, the PyInit_spam() function is not called automatically unless there’s an entry in the PyImport_Inittab table. To add the module to the initialization table, use PyImport_AppendInittab(), optionally followed by an import of the module:

#define PY_SSIZE_T_CLEAN
#include <Python.h>

int
main(int argc, char *argv[])
{
    PyStatus status;
    PyConfig config;
    PyConfig_InitPythonConfig(&config);

    /* Add a built-in module, before Py_Initialize */
    if (PyImport_AppendInittab("spam", PyInit_spam) == -1) {
        fprintf(stderr, "Error: could not extend in-built modules table\n");
        exit(1);
    }

    /* Pass argv[0] to the Python interpreter */
    status = PyConfig_SetBytesString(&config, &config.program_name, argv[0]);
    if (PyStatus_Exception(status)) {
        goto exception;
    }

    /* Initialize the Python interpreter.  Required.
       If this step fails, it will be a fatal error. */
    status = Py_InitializeFromConfig(&config);
    if (PyStatus_Exception(status)) {
        goto exception;
    }
    PyConfig_Clear(&config);

    /* Optionally import the module; alternatively,
       import can be deferred until the embedded script
       imports it. */
    PyObject *pmodule = PyImport_ImportModule("spam");
    if (!pmodule) {
        PyErr_Print();
        fprintf(stderr, "Error: could not import module 'spam'\n");
    }

    // ... use Python C API here ...

    return 0;

  exception:
     PyConfig_Clear(&config);
     Py_ExitStatusException(status);
}

참고

sys.modules에서 항목을 제거하거나 프로세스 내에서 컴파일된 모듈을 여러 인터프리터로 임포트 하면 (또는 exec()를 개입시키지 않고 fork()를 따르면) 일부 확장 모듈에 문제가 발생할 수 있습니다. 확장 모듈 작성자는 내부 데이터 구조를 초기화할 때 주의를 기울여야 합니다.

더욱 실질적인 예제 모듈이 Modules/xxmodule.c로 파이썬 소스 배포판에 포함되어 있습니다. 이 파일은 템플릿으로 사용되거나 단순히 예제로 읽을 수 있습니다.

참고

spam 예제와 달리 xxmodule은 다단계 초기화(multi-phase initialization)(파이썬 3.5의 새로운 기능)를 사용합니다. 여기서는 PyModuleDef 구조체가 PyInit_spam에서 반환되고, 모듈 생성은 임포트 절차에 맡겨집니다. 다단계 초기화에 대한 자세한 내용은 PEP 489 [https://peps.python.org/pep-0489/]를 참조하십시오.

1.5. 컴파일과 링크

새로운 확장을 사용하기 전에 해야 할 두 가지 작업이 더 있습니다: 컴파일과 파이썬 시스템과의 링크. 동적 로딩을 사용하면, 세부 사항은 시스템이 사용하는 동적 로딩 스타일에 따라 달라질 수 있습니다; 확장 모듈을 빌드하는 것에 관한 장(C와 C++ 확장 빌드하기 장)과 윈도우 빌드에 대한 자세한 정보는 이에만 관련된 추가 정보(윈도우에서 C와 C++ 확장 빌드하기 장)를 참조하십시오.

동적 로딩을 사용할 수 없거나, 모듈을 파이썬 인터프리터의 영구적인 부분으로 만들려면, 구성 설정을 변경하고 인터프리터를 다시 빌드해야 합니다. 운 좋게도, 이것은 유닉스에서 매우 간단합니다: 압축을 푼 소스 배포의 Modules/ 디렉터리에 파일(예를 들어 spammodule.c)을 놓고, Modules/Setup.local 파일에 여러분의 파일을 기술하는 한 줄을 추가하십시오:

spam spammodule.o

그리고 최상위 디렉터리에서 make를 실행하여 인터프리터를 다시 빌드하십시오. Modules/ 서브 디렉터리에서 make를 실행할 수도 있지만, 먼저 ‘make Makefile’을 실행하여 Makefile을 다시 빌드해야 합니다. (이것은 Setup 파일을 변경할 때마다 필요합니다.)

모듈에 링크할 추가 라이브러리가 필요하면, 이것도 구성 파일의 줄에 나열될 수 있습니다, 예를 들어:

spam spammodule.o -lX11

1.6. C에서 파이썬 함수 호출하기

지금까지 파이썬에서 C 함수를 호출할 수 있도록 하는 데 집중했습니다. 그 반대도 유용합니다: C에서 파이썬 함수 호출하기. 이것은 특히 “콜백” 함수를 지원하는 라이브러리의 경우에 해당합니다. C 인터페이스가 콜백을 사용하면, 동등한 파이썬은 종종 파이썬 프로그래머에게 콜백 메커니즘을 제공해야 할 필요가 있습니다; 구현은 C 콜백에서 파이썬 콜백 함수를 호출해야 합니다. 다른 용도도 상상할 수 있습니다.

다행히, 파이썬 인터프리터는 재귀적으로 쉽게 호출되며, 파이썬 함수를 호출하는 표준 인터페이스가 있습니다. (특정 문자열을 입력으로 파이썬 파서를 호출하는 방법에 대해서는 다루지 않겠습니다 — 관심이 있다면, 파이썬 소스 코드에서 Modules/main.c의 -c 명령 줄 옵션 구현을 살펴보십시오.)

파이썬 함수를 호출하기는 쉽습니다. 먼저, 파이썬 프로그램은 어떻게 든 여러분에게 파이썬 함수 객체를 전달해야 합니다. 이를 위해 함수(또는 다른 인터페이스)를 제공해야 합니다. 이 함수가 호출될 때, 전역 변수(또는 여러분이 보기에 적절한 곳 어디에나)에 파이썬 함수 객체에 대한 포인터를 저장하십시오 (Py_INCREF()해야 하는 것에 주의하십시오!). 예를 들어, 다음 함수는 모듈 정의의 일부일 수 있습니다:

static PyObject *my_callback = NULL;

static PyObject *
my_set_callback(PyObject *dummy, PyObject *args)
{
    PyObject *result = NULL;
    PyObject *temp;

    if (PyArg_ParseTuple(args, "O:set_callback", &temp)) {
        if (!PyCallable_Check(temp)) {
            PyErr_SetString(PyExc_TypeError, "parameter must be callable");
            return NULL;
        }
        Py_XINCREF(temp);         /* Add a reference to new callback */
        Py_XDECREF(my_callback);  /* Dispose of previous callback */
        my_callback = temp;       /* Remember new callback */
        /* Boilerplate to return "None" */
        Py_INCREF(Py_None);
        result = Py_None;
    }
    return result;
}

This function must be registered with the interpreter using the METH_VARARGS flag; this is described in section 모듈의 메서드 테이블과 초기화 함수. The PyArg_ParseTuple() function and its arguments are documented in section 확장 함수에서 매개 변수 추출하기.

매크로 Py_XINCREF()와 Py_XDECREF()는 객체의 참조 횟수를 증가/감소시키며 NULL 포인터가 있을 때 안전합니다 (그러나 이 문맥에서 temp는 NULL이 아님에 유의하십시오). 섹션 참조 횟수에 이에 대한 자세한 정보가 있습니다.

나중에, 함수를 호출할 때, C 함수 PyObject_CallObject()를 호출합니다. 이 함수에는 두 개의 인자가 있는데, 모두 임의의 파이썬 객체에 대한 포인터입니다: 파이썬 함수와 인자 목록. 인자 목록은 항상 길이가 인자의 수인 튜플 객체여야 합니다. 인자 없이 파이썬 함수를 호출하려면, NULL이나 빈 튜플을 전달하십시오; 하나의 인자로 호출하려면, 단 항목 튜플을 전달하십시오. Py_BuildValue()는 포맷 문자열이 괄호 사이에 0개 이상의 포맷 코드로 구성되었을 때 튜플을 반환합니다. 예를 들면:

int arg;
PyObject *arglist;
PyObject *result;
...
arg = 123;
...
/* Time to call the callback */
arglist = Py_BuildValue("(i)", arg);
result = PyObject_CallObject(my_callback, arglist);
Py_DECREF(arglist);

PyObject_CallObject()는 파이썬 객체 포인터를 반환합니다: 이것은 파이썬 함수의 반환 값입니다. PyObject_CallObject()는 인자와 관련하여 “참조 횟수 중립적”입니다. 이 예에서는 PyObject_CallObject() 호출 직후 Py_DECREF()되는 인자 목록으로 사용할 새 튜플이 만들어졌습니다.

PyObject_CallObject()의 반환 값은 “새것”입니다: 완전히 새로운 객체이거나 참조 횟수가 증가한 기존 객체입니다. 따라서, 전역 변수에 저장하려는 것이 아닌 한, 설사 (특히!) 그 값에 관심이 없더라도 결과를 Py_DECREF()해야 합니다.

그러나, 이 작업을 수행하기 전에 반환 값이 NULL이 아닌지 확인해야 합니다. 그렇다면, 파이썬 함수는 예외를 발생 시켜 종료한 것입니다. PyObject_CallObject()라는 C 코드가 파이썬에서 호출되었다면 이제 파이썬 호출자에게 에러 표시를 반환하여, 인터프리터가 스택 트레이스를 인쇄하거나 호출하는 파이썬 코드가 예외를 처리할 수 있도록 합니다. 이것이 불가능하거나 바람직하지 않으면, PyErr_Clear()를 호출하여 예외를 지워야 합니다. 예를 들면:

if (result == NULL)
    return NULL; /* Pass error back */
...use result...
Py_DECREF(result);

파이썬 콜백 함수에 대해 원하는 인터페이스에 따라, PyObject_CallObject()에 인자 목록을 제공해야 할 수도 있습니다. 때에 따라 인자 목록은 콜백 함수를 지정한 같은 인터페이스를 통해 파이썬 프로그램에서 제공됩니다. 그런 다음 함수 객체와 같은 방식으로 저장하고 사용할 수 있습니다. 다른 경우에는, 인자 목록으로 전달할 새 튜플을 구성해야 할 수도 있습니다. 이렇게 하는 가장 간단한 방법은 Py_BuildValue()를 호출하는 것입니다. 예를 들어, 정수 이벤트 코드를 전달하려면, 다음 코드를 사용할 수 있습니다:

PyObject *arglist;
...
arglist = Py_BuildValue("(l)", eventcode);
result = PyObject_CallObject(my_callback, arglist);
Py_DECREF(arglist);
if (result == NULL)
    return NULL; /* Pass error back */
/* Here maybe use the result */
Py_DECREF(result);

호출 직후, 에러 점검 전에 Py_DECREF(arglist)의 배치에 유의하십시오! 또한 엄격하게 말하면 이 코드가 완전하지 않음에도 유의하십시오: Py_BuildValue()에 메모리가 부족할 수 있어서 확인해야 합니다.

인자와 키워드 인자를 지원하는 PyObject_Call()을 사용하여 키워드 인자가 있는 함수를 호출할 수도 있습니다. 위의 예에서와같이, Py_BuildValue()를 사용하여 딕셔너리를 구성합니다.

PyObject *dict;
...
dict = Py_BuildValue("{s:i}", "name", val);
result = PyObject_Call(my_callback, NULL, dict);
Py_DECREF(dict);
if (result == NULL)
    return NULL; /* Pass error back */
/* Here maybe use the result */
Py_DECREF(result);

1.7. 확장 함수에서 매개 변수 추출하기

PyArg_ParseTuple() 함수는 다음과 같이 선언됩니다:

int PyArg_ParseTuple(PyObject *arg, const char *format, ...);

arg 인자는 파이썬에서 C 함수로 전달되는 인자 목록이 포함된 튜플 객체여야 합니다. format 인자는 포맷 문자열이어야 하며, 문법은 파이썬/C API 레퍼런스 매뉴얼의 인자 구문 분석과 값 구축에 설명되어 있습니다. 나머지 인자는 포맷 문자열에 의해 형이 결정되는 변수의 주소여야 합니다.

PyArg_ParseTuple()은 파이썬 인자가 요구되는 형인지 확인하지만, 호출에 전달된 C 변수 주소의 유효성을 확인할 수는 없습니다: 실수를 하면, 코드가 충돌하거나 적어도 메모리의 임의 비트를 덮어씁니다. 그러니 조심하십시오!

호출자에게 제공되는 모든 파이썬 객체 참조는 빌려온(borrowed) 참조임에 유의하십시오; 참조 횟수를 줄이지 마십시오!

몇 가지 예제 호출:

#define PY_SSIZE_T_CLEAN
#include <Python.h>

int ok;
int i, j;
long k, l;
const char *s;
Py_ssize_t size;

ok = PyArg_ParseTuple(args, ""); /* No arguments */
    /* Python call: f() */

ok = PyArg_ParseTuple(args, "s", &s); /* A string */
    /* Possible Python call: f('whoops!') */

ok = PyArg_ParseTuple(args, "lls", &k, &l, &s); /* Two longs and a string */
    /* Possible Python call: f(1, 2, 'three') */

ok = PyArg_ParseTuple(args, "(ii)s#", &i, &j, &s, &size);
    /* A pair of ints and a string, whose size is also returned */
    /* Possible Python call: f((1, 2), 'three') */

{
    const char *file;
    const char *mode = "r";
    int bufsize = 0;
    ok = PyArg_ParseTuple(args, "s|si", &file, &mode, &bufsize);
    /* A string, and optionally another string and an integer */
    /* Possible Python calls:
       f('spam')
       f('spam', 'w')
       f('spam', 'wb', 100000) */
}

{
    int left, top, right, bottom, h, v;
    ok = PyArg_ParseTuple(args, "((ii)(ii))(ii)",
             &left, &top, &right, &bottom, &h, &v);
    /* A rectangle and a point */
    /* Possible Python call:
       f(((0, 0), (400, 300)), (10, 10)) */
}

{
    Py_complex c;
    ok = PyArg_ParseTuple(args, "D:myfunction", &c);
    /* a complex, also providing a function name for errors */
    /* Possible Python call: myfunction(1+2j) */
}

1.8. 확장 함수를 위한 키워드 매개 변수

PyArg_ParseTupleAndKeywords() 함수는 다음과 같이 선언됩니다:

int PyArg_ParseTupleAndKeywords(PyObject *arg, PyObject *kwdict,
                                const char *format, char * const *kwlist, ...);

arg와 format 매개 변수는 PyArg_ParseTuple() 함수와 동일합니다. kwdict 매개 변수는 파이썬 런타임에서 세 번째 매개 변수로 수신된 키워드 딕셔너리입니다. kwlist 매개 변수는 매개 변수를 식별하는 문자열의 NULL 종료 목록입니다; 이름은 왼쪽에서 오른쪽으로 format의 형 정보와 일치합니다. 성공하면, PyArg_ParseTupleAndKeywords()는 참을 반환하고, 그렇지 않으면 거짓을 반환하고 적절한 예외를 발생시킵니다.

참고

키워드 인자를 사용할 때 중첩된 튜플을 구문분석할 수 없습니다! kwlist에 없는 키워드 매개 변수가 전달되면 TypeError를 발생시킵니다.

다음은 Geoff Philbrick (philbrick@hks.com) 의 예제를 기반으로 한, 키워드를 사용하는 예제 모듈입니다:

#define PY_SSIZE_T_CLEAN
#include <Python.h>

static PyObject *
keywdarg_parrot(PyObject *self, PyObject *args, PyObject *keywds)
{
    int voltage;
    const char *state = "a stiff";
    const char *action = "voom";
    const char *type = "Norwegian Blue";

    static char *kwlist[] = {"voltage", "state", "action", "type", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "i|sss", kwlist,
                                     &voltage, &state, &action, &type))
        return NULL;

    printf("-- This parrot wouldn't %s if you put %i Volts through it.\n",
           action, voltage);
    printf("-- Lovely plumage, the %s -- It's %s!\n", type, state);

    Py_RETURN_NONE;
}

static PyMethodDef keywdarg_methods[] = {
    /* The cast of the function is necessary since PyCFunction values
     * only take two PyObject* parameters, and keywdarg_parrot() takes
     * three.
     */
    {"parrot", (PyCFunction)(void(*)(void))keywdarg_parrot, METH_VARARGS | METH_KEYWORDS,
     "Print a lovely skit to standard output."},
    {NULL, NULL, 0, NULL}   /* sentinel */
};

static struct PyModuleDef keywdargmodule = {
    PyModuleDef_HEAD_INIT,
    "keywdarg",
    NULL,
    -1,
    keywdarg_methods
};

PyMODINIT_FUNC
PyInit_keywdarg(void)
{
    return PyModule_Create(&keywdargmodule);
}

1.9. 임의의 값을 구축하기

이 함수는 PyArg_ParseTuple()의 반대입니다. 다음과 같이 선언됩니다:

PyObject *Py_BuildValue(const char *format, ...);

PyArg_ParseTuple()에서 인식되는 것과 유사한 포맷 단위 집합을 인식하지만, 인자(함수의 출력이 아니라 입력입니다)는 포인터가 아니라 그냥 값이어야 합니다. 파이썬에서 호출한 C 함수에서 반환하기에 적합한 새 파이썬 객체를 반환합니다.

PyArg_ParseTuple()과의 한 가지 차이점: 후자는 첫 번째 인자가 튜플이어야 하지만 (파이썬 인자 목록은 항상 내부적으로 튜플로 표현되기 때문입니다), Py_BuildValue()는 항상 튜플을 빌드하지는 않습니다. 포맷 문자열에 둘 이상의 포맷 단위가 포함된 경우에만 튜플을 빌드합니다. 포맷 문자열이 비어 있으면 None을 반환합니다; 정확히 하나의 포맷 단위를 포함하면, 그것이 무엇이건 해당 포맷 단위가 기술하는 객체를 반환합니다. 크기가 0이나 1인 튜플을 강제로 반환하도록 하려면, 포맷 문자열을 괄호로 묶으십시오.

예제 (왼쪽은 호출이고, 오른쪽은 결과 파이썬 값입니다):

Py_BuildValue("")                        None
Py_BuildValue("i", 123)                  123
Py_BuildValue("iii", 123, 456, 789)      (123, 456, 789)
Py_BuildValue("s", "hello")              'hello'
Py_BuildValue("y", "hello")              b'hello'
Py_BuildValue("ss", "hello", "world")    ('hello', 'world')
Py_BuildValue("s#", "hello", 4)          'hell'
Py_BuildValue("y#", "hello", 4)          b'hell'
Py_BuildValue("()")                      ()
Py_BuildValue("(i)", 123)                (123,)
Py_BuildValue("(ii)", 123, 456)          (123, 456)
Py_BuildValue("(i,i)", 123, 456)         (123, 456)
Py_BuildValue("[i,i]", 123, 456)         [123, 456]
Py_BuildValue("{s:i,s:i}",
              "abc", 123, "def", 456)    {'abc': 123, 'def': 456}
Py_BuildValue("((ii)(ii)) (ii)",
              1, 2, 3, 4, 5, 6)          (((1, 2), (3, 4)), (5, 6))

1.10. 참조 횟수

C나 C++ 와 같은 언어에서, 힙에서 메모리의 동적 할당과 할당 해제하는 것은 프로그래머가 담당합니다. C에서는, malloc()과 free() 함수를 사용하여 이 작업을 수행합니다. C++에서는, 연산자 new와 delete는 본질적으로 같은 의미로 사용되며 우리는 뒤따르는 논의를 C의 경우로 제한하겠습니다.

Every block of memory allocated with malloc() should eventually be returned to the pool of available memory by exactly one call to free(). It is important to call free() at the right time. If a block’s address is forgotten but free() is not called for it, the memory it occupies cannot be reused until the program terminates. This is called a memory leak. On the other hand, if a program calls free() for a block and then continues to use the block, it creates a conflict with reuse of the block through another malloc() call. This is called using freed memory. It has the same bad consequences as referencing uninitialized data — core dumps, wrong results, mysterious crashes.

메모리 누수의 일반적인 원인은 코드를 통한 비정상적인 경로입니다. 예를 들어, 함수는 메모리 블록을 할당하고, 어떤 계산을 한 다음, 블록을 다시 해제할 수 있습니다. 이제 함수에 대한 요구 사항이 변경되어 에러 조건을 감지하는 계산에 대한 검사를 추가하고 함수가 조기에 반환할 수 있도록 합니다. 이 조기 탈출을 수행할 때, 특히 나중에 코드에 추가될 때, 할당된 메모리 블록을 해제하는 것을 잊어버리기 쉽습니다. 이러한 누수는 일단 만들어지면 종종 오랫동안 탐지되지 않습니다: 에러 탈출은 전체 호출의 작은 부분에서만 이루어지며, 대부분의 최신 시스템에는 많은 가상 메모리가 있어서, 누수 하는 함수를 자주 사용하는 오래 실행되는 프로세스에서만 누수가 나타납니다. 따라서, 이런 종류의 에러를 코딩 규칙이나 전략을 통해 누수가 발생하지 않도록 하는 것이 중요합니다.

파이썬은 malloc()과 free()를 많이 사용하기 때문에, 메모리 누수와 해제된 메모리 사용을 피하는 전략이 필요합니다. 선택된 방법을 참조 횟수 세기(reference counting)라고 합니다. 원리는 간단합니다: 모든 객체에는 카운터를 포함합니다, 카운터는 객체에 대한 참조가 어딘가에 저장될 때 증가하고, 참조가 삭제될 때 감소합니다. 카운터가 0에 도달하면, 객체에 대한 마지막 참조가 삭제된 것이고 객체가 해제됩니다.

대체 전략을 자동 가비지 수집(automatic garbage collection)이라고 합니다. (때로는, 참조 횟수 세기도 가비지 수집 전략이라고 해서, 두 가지를 구별하기 위해 “자동”을 붙였습니다.) 자동 가비지 수집의 가장 큰 장점은 사용자가 free()를 명시적으로 호출할 필요가 없다는 것입니다. (또 다른 주장된 이점은 속도나 메모리 사용량의 개선이지만 — 이것은 견고한 사실이 아닙니다.) 단점은 C의 경우 참조 횟수 세기는 이식성 있게 구현할 수 있지만 (함수 malloc()과 free()를 사용할 수 있는 한 — 이는 C 표준이 보장합니다), 실제로 이식성 있는 자동 가비지 수집기가 없다는 것입니다. 언젠가 C를 위해 충분히 이식성 있는 자동 가비지 수집기를 사용할 수 있을 것입니다. 그때까지, 우리는 참조 횟수와 함께 살아야 할 것입니다.

파이썬은 전통적인 참조 횟수 세기 구현을 사용하지만, 참조 순환을 감지하는 순환 감지기도 제공합니다. 이를 통해 응용 프로그램은 직접적이거나 간접적인 순환 참조를 만드는 것(이것이 참조 횟수만 사용하여 구현된 가비지 수집의 약점입니다)에 대해 걱정하지 않아도 됩니다. 참조 순환은 (어쩌면 간접적으로) 자신에 대한 참조를 포함하는 객체로 구성되어서, 순환의 각 객체는 0이 아닌 참조 횟수를 갖습니다. 일반적인 참조 횟수 세기 구현에서는 순환 자체에 대한 추가 참조가 없더라도 참조 순환의 객체에 속하는 메모리나 순환에 속한 객체에서 참조된 메모리를 회수할 수 없습니다.

The cycle detector is able to detect garbage cycles and can reclaim them. The gc module exposes a way to run the detector (the collect() function), as well as configuration interfaces and the ability to disable the detector at runtime.

1.10.1. 파이썬에서 참조 횟수 세기

참조 횟수의 증가와 감소를 처리하는 두 개의 매크로 Py_INCREF(x)와 Py_DECREF(x)가 있습니다. Py_DECREF()는 횟수가 0에 도달하면 객체를 해제하기도 합니다. 유연성을 위해, free()를 직접 호출하지 않습니다 — 대신, 객체의 형 객체(type object)에 있는 함수 포인터를 통해 호출합니다. 이 목적(및 기타)을 위해 모든 객체에는 해당 형 객체에 대한 포인터도 포함됩니다.

이제 큰 질문이 남습니다: 언제 Py_INCREF(x)와 Py_DECREF(x)를 사용합니까? 먼저 몇 가지 용어를 소개하겠습니다. 아무도 객체를 “소유(owns)”하지 않습니다ㅣ 그러나, 객체에 대한 참조를 소유(own a reference)할 수 있습니다. 객체의 참조 횟수는 이제 이 객체에 대한 참조를 소유한 수로 정의됩니다. 참조 소유자는 더는 참조가 필요하지 않을 때 Py_DECREF()를 호출해야 합니다. 참조의 소유권을 양도할 수 있습니다. 소유한 참조를 처분하는 세 가지 방법이 있습니다: 전달, 저장 및 Py_DECREF() 호출. 소유한 참조를 처분하지 않으면 메모리 누수가 발생합니다.

객체에 대한 참조를 빌리는(borrow) [2] 것도 가능합니다. 참조의 대여자(borrower)는 Py_DECREF()를 호출해서는 안 됩니다. 대여자는 빌린 소유자보다 더 오래 객체를 붙잡아서는 안 됩니다. 소유자가 처분한 후 빌린 참조를 사용하면 해제된 메모리를 사용할 위험이 있어서 절대 피해야 합니다 [3].

참조 소유에 비교할 때 빌리기의 이점은 코드를 통한 가능한 모든 경로에서 참조를 처리할 필요가 없다는 것입니다 — 즉, 빌려온 참조를 사용하면 조기 종료 시에 누수의 위험이 없습니다. 소유하는 것에 비해 빌리는 것의 단점은, 겉보기에는 올바른 코드지만, 빌려준 소유자가 실제로는 참조를 처분한 후에 빌린 참조가 사용될 수 있는 미묘한 상황이 있다는 것입니다.

빌린 참조는 Py_INCREF()를 호출하여 소유한 참조로 변경할 수 있습니다. 이는 참조를 빌려온 소유자의 상태에 영향을 미치지 않습니다 — 새로운 소유된 참조를 만들고, 완전한 소유자 책임을 부여합니다 (이전 소유자뿐만 아니라, 새 소유자는 참조를 올바르게 처분해야 합니다).

1.10.2. 소유권 규칙

객체 참조가 함수 안팎으로 전달될 때마다, 소유권이 참조와 함께 전달되는지 그렇지 않은지는 함수 인터페이스 명세의 일부입니다.

객체에 대한 참조를 반환하는 대부분의 함수는 참조와 함께 소유권을 전달합니다. 특히, PyLong_FromLong()이나 Py_BuildValue()와 같은 새 객체를 만드는 기능을 가진 모든 함수는 소유권을 수신자에게 전달합니다. 객체가 실제로 새 객체가 아니더라도, 여전히 해당 객체에 대한 새 참조의 소유권을 받습니다. 예를 들어, PyLong_FromLong()은 흔히 사용되는 값의 캐시를 유지하고 캐시 된 항목에 대한 참조를 반환할 수 있습니다.

다른 객체에서 객체를 추출하는 많은 함수도 참조와 함께 소유권을 전달합니다, 예를 들어 PyObject_GetAttrString(). 그러나 몇 가지 일반적인 루틴이 예외이기 때문에 그림이 명확하지 않습니다: PyTuple_GetItem(), PyList_GetItem(), PyDict_GetItem() 및 PyDict_GetItemString()은 모두 튜플, 리스트 또는 딕셔너리에서 빌린 참조를 반환합니다.

PyImport_AddModule() 함수도 실제는 반환하는 객체를 만들 수 있지만 빌린 참조를 반환합니다: 객체에 대한 소유한 참조가 sys.modules에 저장되어 있기 때문에 가능합니다.

객체 참조를 다른 함수에 전달할 때, 일반적으로, 함수는 여러분으로부터 참조를 빌립니다 — 참조를 저장해야 하면, Py_INCREF()를 사용하여 독립 소유자가 됩니다. 이 규칙에는 두 가지 중요한 예외가 있습니다: PyTuple_SetItem()과 PyList_SetItem(). 이 함수들은 전달된 항목에 대한 소유권을 취합니다 — 설사 실패하더라도! (PyDict_SetItem()과 그 친구들은 소유권을 취하지 않습니다 — 이들은 “정상” 입니다.)

C 함수가 파이썬에서 호출될 때, 호출자로부터 온 인자에 대한 참조를 빌립니다. 호출자는 객체에 대한 참조를 소유하기 때문에, 빌린 참조의 수명은 함수가 반환될 때까지 보장됩니다. 이러한 빌린 참조를 저장하거나 전달해야 할 때만, Py_INCREF()를 호출하여 소유한 참조로 만들어야 합니다.

파이썬에서 호출된 C 함수에서 반환된 객체 참조는 소유한 참조여야 합니다 — 소유권은 함수에서 호출자로 전달됩니다.

1.10.3. 살얼음

겉보기에 무해한 빌린 참조의 사용이 문제를 일으킬 수 있는 몇 가지 상황이 있습니다. 이것들은 모두 참조의 소유자가 참조를 처분하도록 할 수 있는 인터프리터의 묵시적 호출과 관련이 있습니다.

가장 먼저 알아야 할 가장 중요한 경우는 리스트 항목에 대한 참조를 빌리는 동안 관련이 없는 객체에서 Py_DECREF()를 사용하는 것입니다. 예를 들어:

void
bug(PyObject *list)
{
    PyObject *item = PyList_GetItem(list, 0);

    PyList_SetItem(list, 1, PyLong_FromLong(0L));
    PyObject_Print(item, stdout, 0); /* BUG! */
}

이 함수는 먼저 list[0]에 대한 참조를 빌린 다음, list[1]을 값 0으로 바꾸고, 마지막으로 빌린 참조를 인쇄합니다. 무해해 보이지요? 하지만 그렇지 않습니다!

Let’s follow the control flow into PyList_SetItem(). The list owns references to all its items, so when item 1 is replaced, it has to dispose of the original item 1. Now let’s suppose the original item 1 was an instance of a user-defined class, and let’s further suppose that the class defined a __del__() method. If this class instance has a reference count of 1, disposing of it will call its __del__() method.

Since it is written in Python, the __del__() method can execute arbitrary Python code. Could it perhaps do something to invalidate the reference to item in bug()? You bet! Assuming that the list passed into bug() is accessible to the __del__() method, it could execute a statement to the effect of del list[0], and assuming this was the last reference to that object, it would free the memory associated with it, thereby invalidating item.

문제의 원인을 알고 나면, 해결 방법은 쉽습니다: 일시적으로 참조 횟수를 늘리십시오. 올바른 버전의 함수는 다음과 같습니다:

void
no_bug(PyObject *list)
{
    PyObject *item = PyList_GetItem(list, 0);

    Py_INCREF(item);
    PyList_SetItem(list, 1, PyLong_FromLong(0L));
    PyObject_Print(item, stdout, 0);
    Py_DECREF(item);
}

This is a true story. An older version of Python contained variants of this bug and someone spent a considerable amount of time in a C debugger to figure out why his __del__() methods would fail…

빌린 참조에 문제가 있는 두 번째 경우는 스레드와 관련된 변형입니다. 일반적으로, 파이썬의 전체 객체 공간을 보호하는 전역 록이 있어서, 파이썬 인터프리터의 여러 스레드는 다른 것들의 길에 끼어들 수 없습니다. 그러나, 매크로 Py_BEGIN_ALLOW_THREADS를 사용하여 이 록을 일시적으로 해제하고 Py_END_ALLOW_THREADS를 사용하여 다시 확보할 수 있습니다. 이는 블로킹 I/O 호출에서 흔한데, I/O가 완료되기를 기다리는 동안 다른 스레드가 프로세서를 사용할 수 있도록 합니다. 분명히, 다음 함수는 이전 함수와 같은 문제가 있습니다:

void
bug(PyObject *list)
{
    PyObject *item = PyList_GetItem(list, 0);
    Py_BEGIN_ALLOW_THREADS
    ...some blocking I/O call...
    Py_END_ALLOW_THREADS
    PyObject_Print(item, stdout, 0); /* BUG! */
}

1.10.4. NULL 포인터

일반적으로, 객체 참조를 인자로 취하는 함수는 NULL 포인터를 전달할 것으로 기대하지 않으며, 그렇게 하면 코어를 덤프합니다 (또는 이후의 코어 덤프를 유발합니다). 객체 참조를 반환하는 함수는 일반적으로 예외가 발생했음을 나타내기 위해서만 NULL을 반환합니다. NULL 인자를 검사하지 않는 이유는 함수들이 종종 자신이 받은 객체를 다른 함수에 전달하기 때문입니다 — 각 함수가 NULL을 검사한다면, 중복 검사가 많이 발생하고 코드가 더 느리게 실행됩니다.

NULL일 수 있는 포인터가 수신될 때 “소스”에서만 NULL을 검사하는 것이 좋습니다, 예를 들어, malloc()이나 예외를 발생시킬 수 있는 함수에서.

매크로 Py_INCREF()와 Py_DECREF()는 NULL 포인터를 검사하지 않습니다 — 하지만, 그들의 변형 Py_XINCREF()와 Py_XDECREF()는 확인합니다.

특정 객체 형을 확인하기 위한 매크로(Pytype_Check())는 NULL 포인터를 확인하지 않습니다 — 다시, 여러 기대하는 형에 대해 객체를 검사하기 위해 연속해서 이들을 여러 번 호출하는 코드가 많아서, 중복 검사가 생성됩니다. NULL 검사를 하는 변형은 없습니다.

C 함수 호출 메커니즘은 C 함수에 전달된 인자 목록(예에서는 args)이 절대 NULL이 아님을 보장합니다 — 실제로는 항상 튜플임을 보장합니다 [4].

NULL 포인터를 파이썬 사용자에게 “빠져나가게” 만드는 것은 심각한 에러입니다.

1.11. C++로 확장 작성하기

C++로 확장 모듈을 작성할 수 있습니다. 일부 제한 사항이 적용됩니다. 메인 프로그램(파이썬 인터프리터)이 C 컴파일러로 컴파일되고 링크되면, 생성자가 있는 전역이나 정적(static) 객체를 사용할 수 없습니다. 메인 프로그램이 C++ 컴파일러로 링크된 경우에는 문제가 되지 않습니다. 파이썬 인터프리터가 호출할 함수(특히, 모듈 초기화 함수)는 extern "C"를 사용하여 선언해야 합니다. extern "C" {...}로 파이썬 헤더 파일을 묶을 필요는 없습니다 — __cplusplus 기호가 정의되면 (모든 최신 C++ 컴파일러가 이 기호를 정의합니다) 이미 이 형식을 사용합니다.

1.12. 확장 모듈을 위한 C API 제공하기

많은 확장 모듈은 단지 파이썬에서 사용할 새로운 함수와 형을 제공하지만, 때로 확장 모듈의 코드가 다른 확장 모듈에 유용할 수 있습니다. 예를 들어, 확장 모듈은 순서 없는 리스트처럼 작동하는 “컬렉션” 형을 구현할 수 있습니다. 표준 파이썬 리스트 형에 확장 모듈이 리스트를 만들고 조작할 수 있게 하는 C API가 있는 것처럼, 이 새로운 컬렉션 형에는 다른 확장 모듈에서 직접 조작할 수 있는 C 함수 집합이 있어야 합니다.

첫눈에 이것은 쉬운 것처럼 보입니다; 단지 함수를 작성하고 (물론 static을 선언하지 않고), 적절한 헤더 파일을 제공하고, C API를 설명합니다. 사실 이것은 모든 확장 모듈이 항상 파이썬 인터프리터와 정적으로 링크되어 있다면 작동합니다. 그러나 모듈을 공유 라이브러리로 사용하면, 한 모듈에 정의된 기호가 다른 모듈에서 보이지 않을 수 있습니다. 가시성의 세부 사항은 운영 체제에 따라 다릅니다; 어떤 시스템은 파이썬 인터프리터와 모든 확장 모듈에 하나의 전역 이름 공간을 사용하는 반면 (예를 들어 윈도우), 다른 시스템은 모듈 링크 시점에 임포트 되는 기호의 목록을 명시적으로 요구하거나 (AIX가 하나의 예입니다), 여러 전략 중 선택할 수 있도록 합니다 (대부분의 유닉스). 또한 기호가 전역적으로 보이더라도, 호출하려는 함수를 가진 모듈이 아직 로드되지 않았을 수 있습니다!

따라서 이식성에는 기호 가시성에 대해 가정하지 않을 것이 요구됩니다. 이것은 다른 확장 모듈과의 이름 충돌을 피하고자, 모듈의 초기화 함수를 제외한 확장 모듈의 모든 기호를 static으로 선언해야 함을 의미합니다 (섹션 모듈의 메서드 테이블과 초기화 함수에서 설명되듯이). 그리고 이는 다른 확장 모듈에서 액세스 해야만 하는 기호를 다른 방식으로 노출해야 함을 의미합니다.

Python provides a special mechanism to pass C-level information (pointers) from one extension module to another one: Capsules. A Capsule is a Python data type which stores a pointer (void*). Capsules can only be created and accessed via their C API, but they can be passed around like any other Python object. In particular, they can be assigned to a name in an extension module’s namespace. Other extension modules can then import this module, retrieve the value of this name, and then retrieve the pointer from the Capsule.

확장 모듈의 C API를 노출하는 데 캡슐을 사용하는 방법에는 여러 가지가 있습니다. 각 함수가 자신만의 캡슐을 얻거나, 모든 C API 포인터가 저장된 배열의 주소를 캡슐로 게시할 수 있습니다. 그리고 포인터를 저장하고 꺼내는 다양한 작업은 코드를 제공하는 모듈과 클라이언트 모듈 간에 여러 방식으로 분산될 수 있습니다.

Whichever method you choose, it’s important to name your Capsules properly. The function PyCapsule_New() takes a name parameter (const char*); you’re permitted to pass in a NULL name, but we strongly encourage you to specify a name. Properly named Capsules provide a degree of runtime type-safety; there is no feasible way to tell one unnamed Capsule from another.

특히, C API를 공개하는 데 사용되는 캡슐에는 다음 규칙에 따라 이름을 지정해야 합니다:

modulename.attributename

편의 함수 PyCapsule_Import()를 사용하면 캡슐을 통해 제공된 C API를 쉽게 로드 할 수 있지만, 캡슐 이름이 이 규칙과 일치할 때만 그렇습니다. 이 동작은 C API 사용자에게 자신이 로드 한 캡슐에 올바른 C API가 포함되어 있다는 확신을 줍니다.

The following example demonstrates an approach that puts most of the burden on the writer of the exporting module, which is appropriate for commonly used library modules. It stores all C API pointers (just one in the example!) in an array of void pointers which becomes the value of a Capsule. The header file corresponding to the module provides a macro that takes care of importing the module and retrieving its C API pointers; client modules only have to call this macro before accessing the C API.

The exporting module is a modification of the spam module from section 간단한 예. The function spam.system() does not call the C library function system() directly, but a function PySpam_System(), which would of course do something more complicated in reality (such as adding “spam” to every command). This function PySpam_System() is also exported to other extension modules.

The function PySpam_System() is a plain C function, declared static like everything else:

static int
PySpam_System(const char *command)
{
    return system(command);
}

The function spam_system() is modified in a trivial way:

static PyObject *
spam_system(PyObject *self, PyObject *args)
{
    const char *command;
    int sts;

    if (!PyArg_ParseTuple(args, "s", &command))
        return NULL;
    sts = PySpam_System(command);
    return PyLong_FromLong(sts);
}

모듈의 시작 부분에서, 다음 줄 바로 다음에

#include <Python.h>

다음 두 줄을 더 추가해야 합니다:

#define SPAM_MODULE
#include "spammodule.h"

#define은 헤더 파일이 클라이언트 모듈이 아닌 내보내는 모듈에 포함됨을 알리는 데 사용됩니다. 마지막으로, 모듈의 초기화 함수는 C API 포인터 배열을 초기화해야 합니다:

PyMODINIT_FUNC
PyInit_spam(void)
{
    PyObject *m;
    static void *PySpam_API[PySpam_API_pointers];
    PyObject *c_api_object;

    m = PyModule_Create(&spammodule);
    if (m == NULL)
        return NULL;

    /* Initialize the C API pointer array */
    PySpam_API[PySpam_System_NUM] = (void *)PySpam_System;

    /* Create a Capsule containing the API pointer array's address */
    c_api_object = PyCapsule_New((void *)PySpam_API, "spam._C_API", NULL);

    if (PyModule_Add(m, "_C_API", c_api_object) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

Note that PySpam_API is declared static; otherwise the pointer array would disappear when PyInit_spam() terminates!

작업 대부분은 헤더 파일 spammodule.h에 있으며, 다음과 같습니다:

#ifndef Py_SPAMMODULE_H
#define Py_SPAMMODULE_H
#ifdef __cplusplus
extern "C" {
#endif

/* Header file for spammodule */

/* C API functions */
#define PySpam_System_NUM 0
#define PySpam_System_RETURN int
#define PySpam_System_PROTO (const char *command)

/* Total number of C API pointers */
#define PySpam_API_pointers 1

#ifdef SPAM_MODULE
/* This section is used when compiling spammodule.c */

static PySpam_System_RETURN PySpam_System PySpam_System_PROTO;

#else
/* This section is used in modules that use spammodule's API */

static void **PySpam_API;

#define PySpam_System \
 (*(PySpam_System_RETURN (*)PySpam_System_PROTO) PySpam_API[PySpam_System_NUM])

/* Return -1 on error, 0 on success.
 * PyCapsule_Import will set an exception if there's an error.
 */
static int
import_spam(void)
{
    PySpam_API = (void **)PyCapsule_Import("spam._C_API", 0);
    return (PySpam_API != NULL) ? 0 : -1;
}

#endif

#ifdef __cplusplus
}
#endif

#endif /* !defined(Py_SPAMMODULE_H) */

All that a client module must do in order to have access to the function PySpam_System() is to call the function (or rather macro) import_spam() in its initialization function:

PyMODINIT_FUNC
PyInit_client(void)
{
    PyObject *m;

    m = PyModule_Create(&clientmodule);
    if (m == NULL)
        return NULL;
    if (import_spam() < 0)
        return NULL;
    /* additional initialization can happen here */
    return m;
}

이 방법의 주요 단점은 파일 spammodule.h가 다소 복잡하다는 것입니다. 그러나, 기본 구조는 내보내는 함수마다 같아서, 한 번만 학습하면 됩니다.

마지막으로 캡슐은 추가 기능을 제공하며, 특히 캡슐에 저장된 포인터의 메모리 할당과 할당 해제에 유용합니다. 세부 사항은 파이썬/C API 레퍼런스 매뉴얼의 캡슐 섹션과 캡슐 구현(파이썬 소스 코드 배포의 Include/pycapsule.h와 Objects/pycapsule.c 파일)에 설명되어 있습니다.

각주

[1]

이 함수에 대한 인터페이스는 표준 모듈 os에 이미 존재합니다 — 간단하고 단순한 예제로 선택되었습니다.

[2]

참조 “빌리기(borrowing)” 은유는 완전히 올바르지 않습니다: 소유자는 여전히 참조 사본을 가지고 있습니다.

[3]

참조 횟수가 1 이상인지 확인하는 것은 작동하지 않습니다 — 참조 횟수 자체가 해제된 메모리에 있을 수 있어서 다른 객체에 재사용될 수 있습니다!

[4]

“오래된” 스타일 호출 규칙을 사용할 때 이러한 보장은 유지되지 않습니다 — 이것은 여전히 기존 코드에서 많이 발견됩니다.

2. 확장형 정의하기: 자습서

파이썬은 C 확장 모듈 작성자가 내장 str과 list 형과 마찬가지로 파이썬 코드에서 조작할 수 있는 새로운 형을 정의할 수 있도록 합니다. 모든 확장형의 코드는 패턴을 따르지만, 시작하기 전에 이해해야 할 세부 사항이 있습니다. 이 설명서는 주제에 대한 간단한 소개입니다.

2.1. 기초

The CPython runtime sees all Python objects as variables of type PyObject*, which serves as a “base type” for all Python objects. The PyObject structure itself only contains the object’s reference count and a pointer to the object’s “type object”. This is where the action is; the type object determines which (C) functions get called by the interpreter when, for instance, an attribute gets looked up on an object, a method called, or it is multiplied by another object. These C functions are called “type methods”.

따라서, 새 확장형을 정의하려면, 새 형 객체를 만들어야 합니다.

This sort of thing can only be explained by example, so here’s a minimal, but complete, module that defines a new type named Custom inside a C extension module custom:

참고

여기에 표시하는 것은 정적인(static) 확장형을 정의하는 전통적인 방법입니다. 대부분의 용도에 적합해야 합니다. C API는 또한 PyType_FromSpec() 함수를 사용하여 힙 할당 확장형을 정의 할 수 있습니다만, 이 자습서에서는 다루지 않습니다.

#define PY_SSIZE_T_CLEAN
#include <Python.h>

typedef struct {
    PyObject_HEAD
    /* Type-specific fields go here. */
} CustomObject;

static PyTypeObject CustomType = {
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "custom.Custom",
    .tp_doc = PyDoc_STR("Custom objects"),
    .tp_basicsize = sizeof(CustomObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT,
    .tp_new = PyType_GenericNew,
};

static PyModuleDef custommodule = {
    .m_base = PyModuleDef_HEAD_INIT,
    .m_name = "custom",
    .m_doc = "Example module that creates an extension type.",
    .m_size = -1,
};

PyMODINIT_FUNC
PyInit_custom(void)
{
    PyObject *m;
    if (PyType_Ready(&CustomType) < 0)
        return NULL;

    m = PyModule_Create(&custommodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

이제는 한 번에 배워야 할 것이 많지만, 이전 장과 비슷해 보이기를 바랍니다. 이 파일은 세 가지를 정의합니다:

What a Custom object contains: this is the CustomObject struct, which is allocated once for each Custom instance.

How the Custom type behaves: this is the CustomType struct, which defines a set of flags and function pointers that the interpreter inspects when specific operations are requested.

How to initialize the custom module: this is the PyInit_custom function and the associated custommodule struct.

첫 번째 것은:

typedef struct {
    PyObject_HEAD
} CustomObject;

This is what a Custom object will contain. PyObject_HEAD is mandatory at the start of each object struct and defines a field called ob_base of type PyObject, containing a pointer to a type object and a reference count (these can be accessed using the macros Py_TYPE and Py_REFCNT respectively). The reason for the macro is to abstract away the layout and to enable additional fields in debug builds.

참고

PyObject_HEAD 매크로 뒤에는 세미콜론이 없습니다. 실수로 추가하는 것에 주의하십시오: 일부 컴파일러는 불평할 것입니다.

물론, 객체는 일반적으로 표준 PyObject_HEAD 관용구 외에 추가 데이터를 저장합니다; 예를 들어, 표준 파이썬 floats에 대한 정의는 다음과 같습니다:

typedef struct {
    PyObject_HEAD
    double ob_fval;
} PyFloatObject;

두 번째 것은 형 객체의 정의입니다.

static PyTypeObject CustomType = {
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "custom.Custom",
    .tp_doc = PyDoc_STR("Custom objects"),
    .tp_basicsize = sizeof(CustomObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT,
    .tp_new = PyType_GenericNew,
};

참고

신경 쓰지 않는 모든 PyTypeObject 필드를 나열하지 않고 필드의 선언 순서를 신경 쓰지 않으려면, 위와 같이 C99 스타일의 지명(designated) 초기화자를 사용하는 것이 좋습니다.

object.h에 있는 PyTypeObject의 실제 정의는 위의 정의보다 더 많은 필드를 갖습니다. 나머지 필드는 C 컴파일러에 의해 0으로 채워지며, 필요하지 않으면 명시적으로 지정하지 않는 것이 일반적입니다.

한 번에 한 필드씩 따로 다루려고 합니다:

.ob_base = PyVarObject_HEAD_INIT(NULL, 0)

이 줄은 위에서 언급한 ob_base 필드를 초기화하기 위한 필수 상용구입니다.

.tp_name = "custom.Custom",

우리 형의 이름. 이것은 객체의 기본 텍스트 표현과 일부 에러 메시지에 나타납니다, 예를 들어:

>>> "" + custom.Custom()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can only concatenate str (not "custom.Custom") to str

Note that the name is a dotted name that includes both the module name and the name of the type within the module. The module in this case is custom and the type is Custom, so we set the type name to custom.Custom. Using the real dotted import path is important to make your type compatible with the pydoc and pickle modules.

.tp_basicsize = sizeof(CustomObject),
.tp_itemsize = 0,

This is so that Python knows how much memory to allocate when creating new Custom instances. tp_itemsize is only used for variable-sized objects and should otherwise be zero.

참고

If you want your type to be subclassable from Python, and your type has the same tp_basicsize as its base type, you may have problems with multiple inheritance. A Python subclass of your type will have to list your type first in its __bases__, or else it will not be able to call your type’s __new__() method without getting an error. You can avoid this problem by ensuring that your type has a larger value for tp_basicsize than its base type does. Most of the time, this will be true anyway, because either your base type will be object, or else you will be adding data members to your base type, and therefore increasing its size.

We set the class flags to Py_TPFLAGS_DEFAULT.

.tp_flags = Py_TPFLAGS_DEFAULT,

모든 형은 이 상수를 플래그에 포함해야 합니다. 적어도 파이썬 3.3까지 정의된 모든 멤버를 활성화합니다. 추가 멤버가 필요하면, 해당 플래그를 OR 해야 합니다.

tp_doc에 형의 독스트링을 제공합니다.

.tp_doc = PyDoc_STR("Custom objects"),

To enable object creation, we have to provide a tp_new handler. This is the equivalent of the Python method __new__(), but has to be specified explicitly. In this case, we can just use the default implementation provided by the API function PyType_GenericNew().

.tp_new = PyType_GenericNew,

Everything else in the file should be familiar, except for some code in PyInit_custom():

if (PyType_Ready(&CustomType) < 0)
    return;

This initializes the Custom type, filling in a number of members to the appropriate default values, including ob_type that we initially set to NULL.

if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
    Py_DECREF(m);
    return NULL;
}

This adds the type to the module dictionary. This allows us to create Custom instances by calling the Custom class:

>>> import custom
>>> mycustom = custom.Custom()

That’s it! All that remains is to build it; put the above code in a file called custom.c,

[build-system]
requires = ["setuptools"]
build-backend = "setuptools.build_meta"

[project]
name = "custom"
version = "1"

in a file called pyproject.toml, and

from setuptools import Extension, setup
setup(ext_modules=[Extension("custom", ["custom.c"])])

를 setup.py라는 파일에 넣은 다음; 다음을

$ python -m pip install .

in a shell should produce a file custom.so in a subdirectory and install it; now fire up Python — you should be able to import custom and play around with Custom objects.

그렇게 어렵지 않습니다, 그렇지 않나요?

물론, 현재 Custom 형은 그리 흥미롭지 않습니다. 데이터가 없고 아무것도 하지 않습니다. 서브 클래싱조차 할 수 없습니다.

2.2. 기초 예제에 데이터와 메서드 추가하기

Let’s extend the basic example to add some data and methods. Let’s also make the type usable as a base class. We’ll create a new module, custom2 that adds these capabilities:

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stddef.h> /* for offsetof() */

typedef struct {
    PyObject_HEAD
    PyObject *first; /* first name */
    PyObject *last;  /* last name */
    int number;
} CustomObject;

static void
Custom_dealloc(CustomObject *self)
{
    Py_XDECREF(self->first);
    Py_XDECREF(self->last);
    Py_TYPE(self)->tp_free((PyObject *) self);
}

static PyObject *
Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    CustomObject *self;
    self = (CustomObject *) type->tp_alloc(type, 0);
    if (self != NULL) {
        self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->first == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->last == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->number = 0;
    }
    return (PyObject *) self;
}

static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"first", "last", "number", NULL};
    PyObject *first = NULL, *last = NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
                                     &first, &last,
                                     &self->number))
        return -1;

    if (first) {
        Py_XSETREF(self->first, Py_NewRef(first));
    }
    if (last) {
        Py_XSETREF(self->last, Py_NewRef(last));
    }
    return 0;
}

static PyMemberDef Custom_members[] = {
    {"first", Py_T_OBJECT_EX, offsetof(CustomObject, first), 0,
     "first name"},
    {"last", Py_T_OBJECT_EX, offsetof(CustomObject, last), 0,
     "last name"},
    {"number", Py_T_INT, offsetof(CustomObject, number), 0,
     "custom number"},
    {NULL}  /* Sentinel */
};

static PyObject *
Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
{
    if (self->first == NULL) {
        PyErr_SetString(PyExc_AttributeError, "first");
        return NULL;
    }
    if (self->last == NULL) {
        PyErr_SetString(PyExc_AttributeError, "last");
        return NULL;
    }
    return PyUnicode_FromFormat("%S %S", self->first, self->last);
}

static PyMethodDef Custom_methods[] = {
    {"name", (PyCFunction) Custom_name, METH_NOARGS,
     "Return the name, combining the first and last name"
    },
    {NULL}  /* Sentinel */
};

static PyTypeObject CustomType = {
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "custom2.Custom",
    .tp_doc = PyDoc_STR("Custom objects"),
    .tp_basicsize = sizeof(CustomObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
    .tp_new = Custom_new,
    .tp_init = (initproc) Custom_init,
    .tp_dealloc = (destructor) Custom_dealloc,
    .tp_members = Custom_members,
    .tp_methods = Custom_methods,
};

static PyModuleDef custommodule = {
    .m_base =PyModuleDef_HEAD_INIT,
    .m_name = "custom2",
    .m_doc = "Example module that creates an extension type.",
    .m_size = -1,
};

PyMODINIT_FUNC
PyInit_custom2(void)
{
    PyObject *m;
    if (PyType_Ready(&CustomType) < 0)
        return NULL;

    m = PyModule_Create(&custommodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

이 버전의 모듈에는 여러 가지 변경 사항이 있습니다.

The Custom type now has three data attributes in its C struct, first, last, and number. The first and last variables are Python strings containing first and last names. The number attribute is a C integer.

객체 구조체는 다음과 같이 갱신됩니다:

typedef struct {
    PyObject_HEAD
    PyObject *first; /* first name */
    PyObject *last;  /* last name */
    int number;
} CustomObject;

이제 관리할 데이터가 있기 때문에, 객체 할당과 할당 해제에 관해 더욱 신중해야 합니다. 최소한, 할당 해제 메서드가 필요합니다:

static void
Custom_dealloc(CustomObject *self)
{
    Py_XDECREF(self->first);
    Py_XDECREF(self->last);
    Py_TYPE(self)->tp_free((PyObject *) self);
}

이는 tp_dealloc 멤버에 대입됩니다:

.tp_dealloc = (destructor) Custom_dealloc,

This method first clears the reference counts of the two Python attributes. Py_XDECREF() correctly handles the case where its argument is NULL (which might happen here if tp_new failed midway). It then calls the tp_free member of the object’s type (computed by Py_TYPE(self)) to free the object’s memory. Note that the object’s type might not be CustomType, because the object may be an instance of a subclass.

참고

CustomObject * 인자를 취하도록 Custom_dealloc을 정의했지만, tp_dealloc 함수 포인터는 PyObject * 인자를 받을 것으로 기대하기 때문에 위의 destructor로의 명시적 캐스트가 필요합니다. 그렇지 않으면, 컴파일러에서 경고가 발생합니다. 이것이 C로 하는 객체 지향 다형성입니다!

우리는 성과 이름이 빈 문자열로 초기화되도록 하고 싶어서, tp_new 구현을 제공합니다:

static PyObject *
Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    CustomObject *self;
    self = (CustomObject *) type->tp_alloc(type, 0);
    if (self != NULL) {
        self->first = PyUnicode_FromString("");
        if (self->first == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->last = PyUnicode_FromString("");
        if (self->last == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->number = 0;
    }
    return (PyObject *) self;
}

그리고 그것을 tp_new 멤버에 설치합니다:

.tp_new = Custom_new,

The tp_new handler is responsible for creating (as opposed to initializing) objects of the type. It is exposed in Python as the __new__() method. It is not required to define a tp_new member, and indeed many extension types will simply reuse PyType_GenericNew() as done in the first version of the Custom type above. In this case, we use the tp_new handler to initialize the first and last attributes to non-NULL default values.

tp_new는 인스턴스 화 되는 형(서브 클래스가 인스턴스 화 되면, 반드시 CustomType일 필요는 없습니다)과 형이 호출될 때 전달된 모든 인자가 전달되며, 만들어진 인스턴스를 반환할 것으로 기대됩니다. tp_new 처리기는 항상 위치와 키워드 인자를 받아들이지만, 종종 인자를 무시하고 인자 처리를 초기화 (C의 tp_init나 파이썬의 __init__) 메서드에게 남겨둡니다.

참고

인터프리터가 직접 할 것이라서, tp_new는 명시적으로 tp_init를 호출하면 안 됩니다.

tp_new 구현은 tp_alloc 슬롯을 호출하여 메모리를 할당합니다:

self = (CustomObject *) type->tp_alloc(type, 0);

메모리 할당이 실패할 수 있어서, 진행하기 전에 tp_alloc 결과가 NULL이 아닌지 확인해야 합니다.

참고

우리는 tp_alloc 슬롯을 직접 채우지 않았습니다. 대신 PyType_Ready()가 베이스 클래스(기본적으로 object입니다)에서 상속하여 이를 채웁니다. 대부분의 형은 기본 할당 전략을 사용합니다.

참고

If you are creating a co-operative tp_new (one that calls a base type’s tp_new or __new__()), you must not try to determine what method to call using method resolution order at runtime. Always statically determine what type you are going to call, and call its tp_new directly, or via type->tp_base->tp_new. If you do not do this, Python subclasses of your type that also inherit from other Python-defined classes may not work correctly. (Specifically, you may not be able to create instances of such subclasses without getting a TypeError.)

인스턴스의 초깃값을 제공하는 인자를 받아들이는 초기화 함수도 정의합니다:

static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"first", "last", "number", NULL};
    PyObject *first = NULL, *last = NULL, *tmp;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
                                     &first, &last,
                                     &self->number))
        return -1;

    if (first) {
        tmp = self->first;
        Py_INCREF(first);
        self->first = first;
        Py_XDECREF(tmp);
    }
    if (last) {
        tmp = self->last;
        Py_INCREF(last);
        self->last = last;
        Py_XDECREF(tmp);
    }
    return 0;
}

이것으로 tp_init 슬롯을 채웁니다:

.tp_init = (initproc) Custom_init,

The tp_init slot is exposed in Python as the __init__() method. It is used to initialize an object after it’s created. Initializers always accept positional and keyword arguments, and they should return either 0 on success or -1 on error.

Unlike the tp_new handler, there is no guarantee that tp_init is called at all (for example, the pickle module by default doesn’t call __init__() on unpickled instances). It can also be called multiple times. Anyone can call the __init__() method on our objects. For this reason, we have to be extra careful when assigning the new attribute values. We might be tempted, for example to assign the first member like this:

if (first) {
    Py_XDECREF(self->first);
    Py_INCREF(first);
    self->first = first;
}

하지만 이것은 위험합니다. 우리 형은 first 멤버의 형을 제한하지 않아서, 모든 종류의 객체가 될 수 있습니다. first 멤버에 액세스하려고 시도하는 코드가 실행되도록 하는 파괴자가 있을 수 있습니다; 또는 파괴자가 전역 인터프리터 록을 해제하고 다른 스레드에서 객체에 액세스하고 수정하는 임의의 코드가 실행되도록 할 수 있습니다.

편집증적이 되고 이 가능성으로부터 우리 자신을 보호하기 위해, 우리는 거의 항상 참조 횟수를 줄이기 전에 멤버를 다시 대입합니다. 언제 이렇게 하지 않아도 될까요?

참조 횟수가 1보다 크다는 것을 확실히 알고 있을 때;

객체의 할당 해제가 GIL을 해제하지도 않고 형의 코드를 다시 호출하지도 않음을 알고 있을 때 [1];

순환 가비지 수거를 지원하지 않는 형의 tp_dealloc 처리기에서 참조 횟수를 감소시킬 때 [2].

인스턴스 변수를 어트리뷰트로 노출하려고 합니다. 이를 수행하는 방법에는 여러 가지가 있습니다. 가장 간단한 방법은 멤버 정의를 정의하는 것입니다:

static PyMemberDef Custom_members[] = {
    {"first", Py_T_OBJECT_EX, offsetof(CustomObject, first), 0,
     "first name"},
    {"last", Py_T_OBJECT_EX, offsetof(CustomObject, last), 0,
     "last name"},
    {"number", Py_T_INT, offsetof(CustomObject, number), 0,
     "custom number"},
    {NULL}  /* Sentinel */
};

그리고 tp_members 슬롯에 정의를 넣습니다:

.tp_members = Custom_members,

각 멤버 정의에는 멤버 이름, 형, 오프셋, 액세스 플래그 및 독스트링이 있습니다. 자세한 내용은 아래 범용 어트리뷰트 관리 섹션을 참조하십시오.

이 접근법의 단점은 파이썬 어트리뷰트에 대입할 수 있는 객체의 형을 제한할 방법을 제공하지 않는다는 것입니다. 이름과 성은 문자열일 것으로 기대하지만, 모든 파이썬 객체를 할당할 수 있습니다. 또한 어트리뷰트를 삭제할 수 있습니다, C 포인터를 NULL로 설정합니다. NULL이 아닌 값으로 멤버를 초기화 할 수 있지만, 어트리뷰트를 삭제하면 멤버를 NULL로 설정할 수 있습니다.

We define a single method, Custom.name(), that outputs the objects name as the concatenation of the first and last names.

static PyObject *
Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
{
    if (self->first == NULL) {
        PyErr_SetString(PyExc_AttributeError, "first");
        return NULL;
    }
    if (self->last == NULL) {
        PyErr_SetString(PyExc_AttributeError, "last");
        return NULL;
    }
    return PyUnicode_FromFormat("%S %S", self->first, self->last);
}

The method is implemented as a C function that takes a Custom (or Custom subclass) instance as the first argument. Methods always take an instance as the first argument. Methods often take positional and keyword arguments as well, but in this case we don’t take any and don’t need to accept a positional argument tuple or keyword argument dictionary. This method is equivalent to the Python method:

def name(self):
    return "%s %s" % (self.first, self.last)

Note that we have to check for the possibility that our first and last members are NULL. This is because they can be deleted, in which case they are set to NULL. It would be better to prevent deletion of these attributes and to restrict the attribute values to be strings. We’ll see how to do that in the next section.

이제 메서드를 정의했습니다, 메서드 정의 배열을 만들어야 합니다:

static PyMethodDef Custom_methods[] = {
    {"name", (PyCFunction) Custom_name, METH_NOARGS,
     "Return the name, combining the first and last name"
    },
    {NULL}  /* Sentinel */
};

(note that we used the METH_NOARGS flag to indicate that the method is expecting no arguments other than self)

그리고 tp_methods 슬롯에 대입합니다:

.tp_methods = Custom_methods,

Finally, we’ll make our type usable as a base class for subclassing. We’ve written our methods carefully so far so that they don’t make any assumptions about the type of the object being created or used, so all we need to do is to add the Py_TPFLAGS_BASETYPE to our class flag definition:

.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,

We rename PyInit_custom() to PyInit_custom2(), update the module name in the PyModuleDef struct, and update the full class name in the PyTypeObject struct.

Finally, we update our setup.py file to include the new module,

from setuptools import Extension, setup
setup(ext_modules=[
    Extension("custom", ["custom.c"]),
    Extension("custom2", ["custom2.c"]),
])

and then we re-install so that we can import custom2:

$ python -m pip install .

2.3. 데이터 어트리뷰트를 더 세밀하게 제어하기

In this section, we’ll provide finer control over how the first and last attributes are set in the Custom example. In the previous version of our module, the instance variables first and last could be set to non-string values or even deleted. We want to make sure that these attributes always contain strings.

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stddef.h> /* for offsetof() */

typedef struct {
    PyObject_HEAD
    PyObject *first; /* first name */
    PyObject *last;  /* last name */
    int number;
} CustomObject;

static void
Custom_dealloc(CustomObject *self)
{
    Py_XDECREF(self->first);
    Py_XDECREF(self->last);
    Py_TYPE(self)->tp_free((PyObject *) self);
}

static PyObject *
Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    CustomObject *self;
    self = (CustomObject *) type->tp_alloc(type, 0);
    if (self != NULL) {
        self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->first == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->last == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->number = 0;
    }
    return (PyObject *) self;
}

static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"first", "last", "number", NULL};
    PyObject *first = NULL, *last = NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                     &first, &last,
                                     &self->number))
        return -1;

    if (first) {
        Py_SETREF(self->first, Py_NewRef(first));
    }
    if (last) {
        Py_SETREF(self->last, Py_NewRef(last));
    }
    return 0;
}

static PyMemberDef Custom_members[] = {
    {"number", Py_T_INT, offsetof(CustomObject, number), 0,
     "custom number"},
    {NULL}  /* Sentinel */
};

static PyObject *
Custom_getfirst(CustomObject *self, void *closure)
{
    return Py_NewRef(self->first);
}

static int
Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
{
    if (value == NULL) {
        PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
        return -1;
    }
    if (!PyUnicode_Check(value)) {
        PyErr_SetString(PyExc_TypeError,
                        "The first attribute value must be a string");
        return -1;
    }
    Py_SETREF(self->first, Py_NewRef(value));
    return 0;
}

static PyObject *
Custom_getlast(CustomObject *self, void *closure)
{
    return Py_NewRef(self->last);
}

static int
Custom_setlast(CustomObject *self, PyObject *value, void *closure)
{
    if (value == NULL) {
        PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
        return -1;
    }
    if (!PyUnicode_Check(value)) {
        PyErr_SetString(PyExc_TypeError,
                        "The last attribute value must be a string");
        return -1;
    }
    Py_SETREF(self->last, Py_NewRef(value));
    return 0;
}

static PyGetSetDef Custom_getsetters[] = {
    {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
     "first name", NULL},
    {"last", (getter) Custom_getlast, (setter) Custom_setlast,
     "last name", NULL},
    {NULL}  /* Sentinel */
};

static PyObject *
Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
{
    return PyUnicode_FromFormat("%S %S", self->first, self->last);
}

static PyMethodDef Custom_methods[] = {
    {"name", (PyCFunction) Custom_name, METH_NOARGS,
     "Return the name, combining the first and last name"
    },
    {NULL}  /* Sentinel */
};

static PyTypeObject CustomType = {
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "custom3.Custom",
    .tp_doc = PyDoc_STR("Custom objects"),
    .tp_basicsize = sizeof(CustomObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
    .tp_new = Custom_new,
    .tp_init = (initproc) Custom_init,
    .tp_dealloc = (destructor) Custom_dealloc,
    .tp_members = Custom_members,
    .tp_methods = Custom_methods,
    .tp_getset = Custom_getsetters,
};

static PyModuleDef custommodule = {
    .m_base = PyModuleDef_HEAD_INIT,
    .m_name = "custom3",
    .m_doc = "Example module that creates an extension type.",
    .m_size = -1,
};

PyMODINIT_FUNC
PyInit_custom3(void)
{
    PyObject *m;
    if (PyType_Ready(&CustomType) < 0)
        return NULL;

    m = PyModule_Create(&custommodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

To provide greater control, over the first and last attributes, we’ll use custom getter and setter functions. Here are the functions for getting and setting the first attribute:

static PyObject *
Custom_getfirst(CustomObject *self, void *closure)
{
    Py_INCREF(self->first);
    return self->first;
}

static int
Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
{
    PyObject *tmp;
    if (value == NULL) {
        PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
        return -1;
    }
    if (!PyUnicode_Check(value)) {
        PyErr_SetString(PyExc_TypeError,
                        "The first attribute value must be a string");
        return -1;
    }
    tmp = self->first;
    Py_INCREF(value);
    self->first = value;
    Py_DECREF(tmp);
    return 0;
}

The getter function is passed a Custom object and a “closure”, which is a void pointer. In this case, the closure is ignored. (The closure supports an advanced usage in which definition data is passed to the getter and setter. This could, for example, be used to allow a single set of getter and setter functions that decide the attribute to get or set based on data in the closure.)

The setter function is passed the Custom object, the new value, and the closure. The new value may be NULL, in which case the attribute is being deleted. In our setter, we raise an error if the attribute is deleted or if its new value is not a string.

PyGetSetDef 구조체의 배열을 만듭니다:

static PyGetSetDef Custom_getsetters[] = {
    {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
     "first name", NULL},
    {"last", (getter) Custom_getlast, (setter) Custom_setlast,
     "last name", NULL},
    {NULL}  /* Sentinel */
};

그리고 tp_getset 슬롯에 등록합니다:

.tp_getset = Custom_getsetters,

PyGetSetDef 구조체의 마지막 항목은 위에서 언급한 “클로저”입니다. 이 경우, 클로저를 사용하지 않아서, NULL만 전달합니다.

또한 이러한 어트리뷰트에 대한 멤버 정의를 제거합니다:

static PyMemberDef Custom_members[] = {
    {"number", Py_T_INT, offsetof(CustomObject, number), 0,
     "custom number"},
    {NULL}  /* Sentinel */
};

또한 문자열만 전달되도록 [3] tp_init 처리기를 갱신해야 합니다:

static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"first", "last", "number", NULL};
    PyObject *first = NULL, *last = NULL, *tmp;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                     &first, &last,
                                     &self->number))
        return -1;

    if (first) {
        tmp = self->first;
        Py_INCREF(first);
        self->first = first;
        Py_DECREF(tmp);
    }
    if (last) {
        tmp = self->last;
        Py_INCREF(last);
        self->last = last;
        Py_DECREF(tmp);
    }
    return 0;
}

이러한 변경을 통해, first와 last 멤버가 절대 NULL이 아니라고 확신할 수 있어서, 거의 모든 경우에 NULL 값 검사를 제거할 수 있습니다. 이것은 대부분의 Py_XDECREF() 호출이 Py_DECREF() 호출로 변환될 수 있음을 의미합니다. 이러한 호출을 변경할 수 없는 유일한 장소는 tp_dealloc 구현에서인데, tp_new에서 이 멤버의 초기화가 실패했을 가능성이 있습니다.

또한 이전과 마찬가지로, 초기화 함수에서 모듈 초기화 함수와 모듈 이름을 바꾸고, setup.py 파일에 추가 정의를 추가합니다.

2.4. 순환 가비지 수거 지원하기

파이썬에는 참조 횟수가 0이 아닐 때도 불필요한 객체를 식별할 수 있는 순환 가비지 수거기 (GC)가 있습니다. 이것은 객체가 순환에 참여할 때 일어날 수 있습니다. 예를 들어, 다음을 고려하십시오:

>>> l = []
>>> l.append(l)
>>> del l

이 예에서, 자신을 포함하는 리스트를 만듭니다. 삭제해도 여전히 자체 참조가 있습니다. 참조 횟수가 0으로 떨어지지 않습니다. 다행스럽게도, 파이썬의 순환 가비지 수거기는 결국 리스트가 가비지임을 확인하고 해제합니다.

In the second version of the Custom example, we allowed any kind of object to be stored in the first or last attributes [4]. Besides, in the second and third versions, we allowed subclassing Custom, and subclasses may add arbitrary attributes. For any of those two reasons, Custom objects can participate in cycles:

>>> import custom3
>>> class Derived(custom3.Custom): pass
...
>>> n = Derived()
>>> n.some_attribute = n

To allow a Custom instance participating in a reference cycle to be properly detected and collected by the cyclic GC, our Custom type needs to fill two additional slots and to enable a flag that enables these slots:

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stddef.h> /* for offsetof() */

typedef struct {
    PyObject_HEAD
    PyObject *first; /* first name */
    PyObject *last;  /* last name */
    int number;
} CustomObject;

static int
Custom_traverse(CustomObject *self, visitproc visit, void *arg)
{
    Py_VISIT(self->first);
    Py_VISIT(self->last);
    return 0;
}

static int
Custom_clear(CustomObject *self)
{
    Py_CLEAR(self->first);
    Py_CLEAR(self->last);
    return 0;
}

static void
Custom_dealloc(CustomObject *self)
{
    PyObject_GC_UnTrack(self);
    Custom_clear(self);
    Py_TYPE(self)->tp_free((PyObject *) self);
}

static PyObject *
Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    CustomObject *self;
    self = (CustomObject *) type->tp_alloc(type, 0);
    if (self != NULL) {
        self->first = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->first == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->last = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
        if (self->last == NULL) {
            Py_DECREF(self);
            return NULL;
        }
        self->number = 0;
    }
    return (PyObject *) self;
}

static int
Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"first", "last", "number", NULL};
    PyObject *first = NULL, *last = NULL;

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                     &first, &last,
                                     &self->number))
        return -1;

    if (first) {
        Py_SETREF(self->first, Py_NewRef(first));
    }
    if (last) {
        Py_SETREF(self->last, Py_NewRef(last));
    }
    return 0;
}

static PyMemberDef Custom_members[] = {
    {"number", Py_T_INT, offsetof(CustomObject, number), 0,
     "custom number"},
    {NULL}  /* Sentinel */
};

static PyObject *
Custom_getfirst(CustomObject *self, void *closure)
{
    return Py_NewRef(self->first);
}

static int
Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
{
    if (value == NULL) {
        PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
        return -1;
    }
    if (!PyUnicode_Check(value)) {
        PyErr_SetString(PyExc_TypeError,
                        "The first attribute value must be a string");
        return -1;
    }
    Py_XSETREF(self->first, Py_NewRef(value));
    return 0;
}

static PyObject *
Custom_getlast(CustomObject *self, void *closure)
{
    return Py_NewRef(self->last);
}

static int
Custom_setlast(CustomObject *self, PyObject *value, void *closure)
{
    if (value == NULL) {
        PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
        return -1;
    }
    if (!PyUnicode_Check(value)) {
        PyErr_SetString(PyExc_TypeError,
                        "The last attribute value must be a string");
        return -1;
    }
    Py_XSETREF(self->last, Py_NewRef(value));
    return 0;
}

static PyGetSetDef Custom_getsetters[] = {
    {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
     "first name", NULL},
    {"last", (getter) Custom_getlast, (setter) Custom_setlast,
     "last name", NULL},
    {NULL}  /* Sentinel */
};

static PyObject *
Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
{
    return PyUnicode_FromFormat("%S %S", self->first, self->last);
}

static PyMethodDef Custom_methods[] = {
    {"name", (PyCFunction) Custom_name, METH_NOARGS,
     "Return the name, combining the first and last name"
    },
    {NULL}  /* Sentinel */
};

static PyTypeObject CustomType = {
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "custom4.Custom",
    .tp_doc = PyDoc_STR("Custom objects"),
    .tp_basicsize = sizeof(CustomObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
    .tp_new = Custom_new,
    .tp_init = (initproc) Custom_init,
    .tp_dealloc = (destructor) Custom_dealloc,
    .tp_traverse = (traverseproc) Custom_traverse,
    .tp_clear = (inquiry) Custom_clear,
    .tp_members = Custom_members,
    .tp_methods = Custom_methods,
    .tp_getset = Custom_getsetters,
};

static PyModuleDef custommodule = {
    .m_base = PyModuleDef_HEAD_INIT,
    .m_name = "custom4",
    .m_doc = "Example module that creates an extension type.",
    .m_size = -1,
};

PyMODINIT_FUNC
PyInit_custom4(void)
{
    PyObject *m;
    if (PyType_Ready(&CustomType) < 0)
        return NULL;

    m = PyModule_Create(&custommodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

첫째, 탐색(traversal) 메서드는 순환 GC가 순환에 참여할 수 있는 서브 객체에 대해 알 수 있도록 합니다:

static int
Custom_traverse(CustomObject *self, visitproc visit, void *arg)
{
    int vret;
    if (self->first) {
        vret = visit(self->first, arg);
        if (vret != 0)
            return vret;
    }
    if (self->last) {
        vret = visit(self->last, arg);
        if (vret != 0)
            return vret;
    }
    return 0;
}

For each subobject that can participate in cycles, we need to call the visit() function, which is passed to the traversal method. The visit() function takes as arguments the subobject and the extra argument arg passed to the traversal method. It returns an integer value that must be returned if it is non-zero.

파이썬은 visit 함수 호출을 자동화하는 Py_VISIT() 매크로를 제공합니다. Py_VISIT()를 사용하면, Custom_traverse에서 관용구 양을 최소화할 수 있습니다:

static int
Custom_traverse(CustomObject *self, visitproc visit, void *arg)
{
    Py_VISIT(self->first);
    Py_VISIT(self->last);
    return 0;
}

참고

Py_VISIT()를 사용하려면 tp_traverse 구현에서 인자 이름을 visit과 arg로 정확하게 지정해야 합니다.

둘째, 순환에 참여할 수 있는 서브 객체를 지우는 메서드를 제공해야 합니다:

static int
Custom_clear(CustomObject *self)
{
    Py_CLEAR(self->first);
    Py_CLEAR(self->last);
    return 0;
}

Py_CLEAR() 매크로 사용에 주목하십시오. 참조 횟수를 줄이면서 임의 형의 데이터 어트리뷰트를 지우는 권장되고 안전한 방법입니다. NULL로 설정하기 전에 어트리뷰트에서 Py_XDECREF()를 대신 호출했으면, 어트리뷰트의 파괴자가 어트리뷰트를 다시 읽는 코드(특히 참조 순환이 있으면 )를 다시 호출할 가능성이 있습니다.

참고

다음과 같이 작성하여 Py_CLEAR()를 에뮬레이션할 수 있습니다:

PyObject *tmp;
tmp = self->first;
self->first = NULL;
Py_XDECREF(tmp);

그런데도, 어트리뷰트를 삭제할 때 항상 Py_CLEAR()를 사용하기가 훨씬 쉽고 에러가 적습니다. 견고성을 희생하면서 세밀한 최적화를 시도하지 마십시오!

할당 해제기 Custom_dealloc은 어트리뷰트를 지울 때 임의의 코드를 호출할 수 있습니다. 이는 함수 내에서 순환 GC가 트리거 될 수 있음을 의미합니다. GC는 참조 횟수가 0이 아니라고 가정하기 때문에, 멤버를 지우기 전에 PyObject_GC_UnTrack()을 호출하여 GC에서 객체를 추적 해제해야 합니다. 다음은 PyObject_GC_UnTrack()과 Custom_clear를 사용하여 다시 구현된 할당 해제기입니다:

static void
Custom_dealloc(CustomObject *self)
{
    PyObject_GC_UnTrack(self);
    Custom_clear(self);
    Py_TYPE(self)->tp_free((PyObject *) self);
}

Finally, we add the Py_TPFLAGS_HAVE_GC flag to the class flags:

.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,

거의 다 됐습니다. 사용자 정의 tp_alloc이나 tp_free 처리기를 작성했으면, 순환 가비지 수거를 위해 이를 수정해야 합니다. 대부분의 확장은 자동으로 제공된 버전을 사용합니다.

2.5. 다른 형의 서브 클래싱

기존 형에서 파생된 새 확장형을 만들 수 있습니다. 확장이 필요한 PyTypeObject를 쉽게 사용할 수 있어서, 내장형에서 상속하기가 가장 쉽습니다. 확장 모듈 간에 이러한 PyTypeObject 구조체를 공유하기 어려울 수 있습니다.

In this example we will create a SubList type that inherits from the built-in list type. The new type will be completely compatible with regular lists, but will have an additional increment() method that increases an internal counter:

>>> import sublist
>>> s = sublist.SubList(range(3))
>>> s.extend(s)
>>> print(len(s))
6
>>> print(s.increment())
1
>>> print(s.increment())
2

#define PY_SSIZE_T_CLEAN
#include <Python.h>

typedef struct {
    PyListObject list;
    int state;
} SubListObject;

static PyObject *
SubList_increment(SubListObject *self, PyObject *unused)
{
    self->state++;
    return PyLong_FromLong(self->state);
}

static PyMethodDef SubList_methods[] = {
    {"increment", (PyCFunction) SubList_increment, METH_NOARGS,
     PyDoc_STR("increment state counter")},
    {NULL},
};

static int
SubList_init(SubListObject *self, PyObject *args, PyObject *kwds)
{
    if (PyList_Type.tp_init((PyObject *) self, args, kwds) < 0)
        return -1;
    self->state = 0;
    return 0;
}

static PyTypeObject SubListType = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "sublist.SubList",
    .tp_doc = PyDoc_STR("SubList objects"),
    .tp_basicsize = sizeof(SubListObject),
    .tp_itemsize = 0,
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
    .tp_init = (initproc) SubList_init,
    .tp_methods = SubList_methods,
};

static PyModuleDef sublistmodule = {
    PyModuleDef_HEAD_INIT,
    .m_name = "sublist",
    .m_doc = "Example module that creates an extension type.",
    .m_size = -1,
};

PyMODINIT_FUNC
PyInit_sublist(void)
{
    PyObject *m;
    SubListType.tp_base = &PyList_Type;
    if (PyType_Ready(&SubListType) < 0)
        return NULL;

    m = PyModule_Create(&sublistmodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "SubList", (PyObject *) &SubListType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

As you can see, the source code closely resembles the Custom examples in previous sections. We will break down the main differences between them.

typedef struct {
    PyListObject list;
    int state;
} SubListObject;

파생형 객체의 주요 차이점은 베이스형의 객체 구조체가 첫 번째 값이어야 한다는 것입니다. 베이스형은 이미 구조체의 시작 부분에 PyObject_HEAD()를 포함합니다.

When a Python object is a SubList instance, its PyObject * pointer can be safely cast to both PyListObject * and SubListObject *:

static int
SubList_init(SubListObject *self, PyObject *args, PyObject *kwds)
{
    if (PyList_Type.tp_init((PyObject *) self, args, kwds) < 0)
        return -1;
    self->state = 0;
    return 0;
}

We see above how to call through to the __init__() method of the base type.

이 패턴은 사용자 정의 tp_new와 tp_dealloc 멤버를 갖는 형을 작성할 때 중요합니다. tp_new 처리기는 실제로 tp_alloc을 사용하여 객체의 메모리를 만들지 말고, 베이스 클래스가 자체 tp_new를 호출하여 처리하도록 해야 합니다.

PyTypeObject 구조체는 형의 구상 베이스 클래스를 지정하는 tp_base를 지원합니다. 크로스 플랫폼 컴파일러 문제로 인해, PyList_Type에 대한 참조로 해당 필드를 직접 채울 수 없습니다; 나중에 모듈 초기화 함수에서 수행해야 합니다:

PyMODINIT_FUNC
PyInit_sublist(void)
{
    PyObject* m;
    SubListType.tp_base = &PyList_Type;
    if (PyType_Ready(&SubListType) < 0)
        return NULL;

    m = PyModule_Create(&sublistmodule);
    if (m == NULL)
        return NULL;

    if (PyModule_AddObjectRef(m, "SubList", (PyObject *) &SubListType) < 0) {
        Py_DECREF(m);
        return NULL;
    }

    return m;
}

PyType_Ready()를 호출하기 전에, 형 구조체에 tp_base 슬롯이 채워져 있어야 합니다. 기존 형을 파생할 때, PyType_GenericNew()로 tp_alloc 슬롯을 채울 필요는 없습니다 – 베이스형의 할당 함수가 상속됩니다.

After that, calling PyType_Ready() and adding the type object to the module is the same as with the basic Custom examples.

각주

[1]

이것은 객체가 문자열이나 부동 소수점과 같은 기본형이라는 것을 알고 있을 때 참입니다.

[2]

우리의 형이 가비지 수거를 지원하지 않기 때문에, 이 예제에서는 tp_dealloc 처리기에서 이것을 사용했습니다.

[3]

우리는 이제 first와 last 멤버가 문자열이라는 것을 알고 있어서, 참조 횟수를 줄이는 데 덜 주의할 수 있지만, 우리는 문자열 서브 클래스의 인스턴스를 받아들입니다. 일반 문자열을 할당 해제하는 것이 우리 객체로 다시 호출되지는 않더라도, 문자열 서브 클래스의 인스턴스를 할당 해제하는 것이 객체로 다시 호출되지 않는다고 보장할 수 없습니다.

[4]

또한, 어트리뷰트가 문자열 인스턴스로 제한된 경우에도, 사용자는 임의의 str 서브 클래스를 전달할 수 있어서 여전히 참조 순환을 만들 수 있습니다.

3. 확장형 정의하기: 여러 가지 주제

이 섹션은 구현할 수 있는 다양한 형 메서드와 그것이 하는 일에 대해 훑어보기를 제공하기 위한 것입니다.

Here is the definition of PyTypeObject, with some fields only used in debug builds omitted:

typedef struct _typeobject {
    PyObject_VAR_HEAD
    const char *tp_name; /* For printing, in format "<module>.<name>" */
    Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

    /* Methods to implement standard operations */

    destructor tp_dealloc;
    Py_ssize_t tp_vectorcall_offset;
    getattrfunc tp_getattr;
    setattrfunc tp_setattr;
    PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
                                    or tp_reserved (Python 3) */
    reprfunc tp_repr;

    /* Method suites for standard classes */

    PyNumberMethods *tp_as_number;
    PySequenceMethods *tp_as_sequence;
    PyMappingMethods *tp_as_mapping;

    /* More standard operations (here for binary compatibility) */

    hashfunc tp_hash;
    ternaryfunc tp_call;
    reprfunc tp_str;
    getattrofunc tp_getattro;
    setattrofunc tp_setattro;

    /* Functions to access object as input/output buffer */
    PyBufferProcs *tp_as_buffer;

    /* Flags to define presence of optional/expanded features */
    unsigned long tp_flags;

    const char *tp_doc; /* Documentation string */

    /* Assigned meaning in release 2.0 */
    /* call function for all accessible objects */
    traverseproc tp_traverse;

    /* delete references to contained objects */
    inquiry tp_clear;

    /* Assigned meaning in release 2.1 */
    /* rich comparisons */
    richcmpfunc tp_richcompare;

    /* weak reference enabler */
    Py_ssize_t tp_weaklistoffset;

    /* Iterators */
    getiterfunc tp_iter;
    iternextfunc tp_iternext;

    /* Attribute descriptor and subclassing stuff */
    struct PyMethodDef *tp_methods;
    struct PyMemberDef *tp_members;
    struct PyGetSetDef *tp_getset;
    // Strong reference on a heap type, borrowed reference on a static type
    struct _typeobject *tp_base;
    PyObject *tp_dict;
    descrgetfunc tp_descr_get;
    descrsetfunc tp_descr_set;
    Py_ssize_t tp_dictoffset;
    initproc tp_init;
    allocfunc tp_alloc;
    newfunc tp_new;
    freefunc tp_free; /* Low-level free-memory routine */
    inquiry tp_is_gc; /* For PyObject_IS_GC */
    PyObject *tp_bases;
    PyObject *tp_mro; /* method resolution order */
    PyObject *tp_cache;
    PyObject *tp_subclasses;
    PyObject *tp_weaklist;
    destructor tp_del;

    /* Type attribute cache version tag. Added in version 2.6 */
    unsigned int tp_version_tag;

    destructor tp_finalize;
    vectorcallfunc tp_vectorcall;

    /* bitset of which type-watchers care about this type */
    unsigned char tp_watched;
} PyTypeObject;

이제 메서드가 아주 많습니다. 너무 걱정하지 마십시오 – 정의하려는 형이 있으면, 이 중 일부만 구현할 가능성이 매우 높습니다.

아마 지금까지 예상했듯이, 이것에 대해 살펴보고 다양한 처리기에 대한 자세한 정보를 제공할 것입니다. 필드의 순서에 영향을 미치는 많은 과거의 짐이 있어서, 구조체에 정의된 순서대로 진행하지 않을 것입니다. 필요한 필드가 포함된 예제를 찾은 다음 새 형에 맞게 값을 변경하기가 종종 가장 쉽습니다.

const char *tp_name; /* For printing */

형의 이름 – 이전 장에서 언급했듯이, 이것은 여러 곳에서 나타나는데, 거의 진단 목적입니다. 그러한 상황에서 도움이 될만한 것을 선택하십시오!

Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

이 필드는 이 형의 새 객체가 만들어질 때 할당할 메모리양을 런타임에 알려줍니다. 파이썬은 가변 길이 구조(생각하세요: 문자열, 튜플)에 대한 지원을 내장하고 있는데, 이때 tp_itemsize 필드가 참여합니다. 이것은 나중에 다룰 것입니다.

const char *tp_doc;

여기에 파이썬 스크립트가 obj.__doc__을 참조하여 독스트링을 꺼낼 때 반환할 문자열(또는 문자열의 주소)을 넣을 수 있습니다.

이제 기본 형 메서드에 대해 살펴보겠습니다 – 대부분의 확장형이 구현할 것들입니다.

3.1. 파이널리제이션과 할당 해제

destructor tp_dealloc;

이 함수는 형의 인스턴스의 참조 횟수가 0으로 줄어들고 파이썬 인터프리터가 그것을 재활용하고자 할 때 호출됩니다. 여러분의 형에 해제할 메모리가 있거나 수행할 기타 정리 작업이 있으면, 여기에 넣을 수 있습니다. 객체 자체도 여기서 해제해야 합니다. 이 함수의 예는 다음과 같습니다:

static void
newdatatype_dealloc(newdatatypeobject *obj)
{
    free(obj->obj_UnderlyingDatatypePtr);
    Py_TYPE(obj)->tp_free((PyObject *)obj);
}

If your type supports garbage collection, the destructor should call PyObject_GC_UnTrack() before clearing any member fields:

static void
newdatatype_dealloc(newdatatypeobject *obj)
{
    PyObject_GC_UnTrack(obj);
    Py_CLEAR(obj->other_obj);
    ...
    Py_TYPE(obj)->tp_free((PyObject *)obj);
}

할당 해제 함수의 중요한 요구 사항 중 하나는 계류 중인 예외를 그대로 남겨 두어야 한다는 것입니다. 인터프리터가 파이썬 스택을 되감을 때 할당 해제기가 자주 호출되기 때문에 중요합니다; 스택이 (정상적인 반환이 아닌) 예외로 인해 되감길 때, 할당 해제기가 예외가 이미 설정되어 있음을 알 수 없도록 하는 것은 아무것도 수행되지 않습니다. 할당 해제기가 수행하는 추가 파이썬 코드가 실행될 수 있도록 하는 추가 조치는 예외가 설정되었음을 감지할 수 있습니다. 이는 인터프리터가 혼동하도록 할 수 있습니다. 이를 방지하는 올바른 방법은 안전하지 않은 조치를 수행하기 전에 계류 중인 예외를 저장하고 완료되면 복원하는 것입니다. PyErr_Fetch()와 PyErr_Restore() 함수를 사용하여 수행할 수 있습니다:

static void
my_dealloc(PyObject *obj)
{
    MyObject *self = (MyObject *) obj;
    PyObject *cbresult;

    if (self->my_callback != NULL) {
        PyObject *err_type, *err_value, *err_traceback;

        /* This saves the current exception state */
        PyErr_Fetch(&err_type, &err_value, &err_traceback);

        cbresult = PyObject_CallNoArgs(self->my_callback);
        if (cbresult == NULL)
            PyErr_WriteUnraisable(self->my_callback);
        else
            Py_DECREF(cbresult);

        /* This restores the saved exception state */
        PyErr_Restore(err_type, err_value, err_traceback);

        Py_DECREF(self->my_callback);
    }
    Py_TYPE(obj)->tp_free((PyObject*)self);
}

참고

할당 해제 함수에서 안전하게 수행할 수 있는 작업에는 제한이 있습니다. 먼저, 형이 가비지 수거를 지원하면 (tp_traverse 및/또는 tp_clear를 사용해서), tp_dealloc이 호출될 때 객체의 일부 멤버가 지워지거나 파이널라이즈 될 수 있습니다. 둘째, tp_dealloc에서, 객체는 불안정한 상태에 있습니다: 참조 횟수가 0입니다. (위의 예에서와같이) 사소하지 않은 객체나 API를 호출하면 tp_dealloc을 다시 호출하게 되어, 이중 해제와 충돌이 발생할 수 있습니다.

파이썬 3.4부터는, tp_dealloc에 복잡한 파이널리제이션 코드를 넣지 말고, 대신 새로운 tp_finalize 형 메서드를 사용하는 것이 좋습니다.

더 보기

PEP 442 [https://peps.python.org/pep-0442/]는 새로운 파이널리제이션 체계를 설명합니다.

3.2. 객체 표현

파이썬에서, 객체의 텍스트 표현을 생성하는 두 가지 방법이 있습니다: repr() 함수와 str() 함수. (print() 함수는 단지 str()을 호출합니다.) 이 처리기들은 모두 선택적입니다.

reprfunc tp_repr;
reprfunc tp_str;

tp_repr 처리기는 호출된 인스턴스의 표현을 포함하는 문자열 객체를 반환해야 합니다. 다음은 간단한 예입니다:

static PyObject *
newdatatype_repr(newdatatypeobject *obj)
{
    return PyUnicode_FromFormat("Repr-ified_newdatatype{{size:%d}}",
                                obj->obj_UnderlyingDatatypePtr->size);
}

If no tp_repr handler is specified, the interpreter will supply a representation that uses the type’s tp_name and a uniquely identifying value for the object.

tp_str 처리기는 str()에 대한 것이고, 위에서 설명한 tp_repr 처리기와 repr() 간의 관계와 같은 관계입니다; 즉, 파이썬 코드가 객체의 인스턴스에서 str()을 호출할 때 호출됩니다. 구현은 tp_repr 함수와 매우 유사하지만, 결과 문자열은 사람이 사용하기 위한 것입니다. tp_str을 지정하지 않으면, tp_repr 처리기가 대신 사용됩니다.

다음은 간단한 예입니다:

static PyObject *
newdatatype_str(newdatatypeobject *obj)
{
    return PyUnicode_FromFormat("Stringified_newdatatype{{size:%d}}",
                                obj->obj_UnderlyingDatatypePtr->size);
}

3.3. 어트리뷰트 관리

어트리뷰트를 지원할 수 있는 모든 객체에 대해, 해당 형은 어트리뷰트가 결정되는(resolved) 방법을 제어하는 함수를 제공해야 합니다. 어트리뷰트를 꺼낼 수 있는 함수와 (뭔가 정의되어 있다면), 어트리뷰트를 설정하는 다른 함수(어트리뷰트 설정이 허용된다면)가 있어야 합니다. 어트리뷰트 제거는 특별한 경우이며, 처리기에 전달된 새 값이 NULL입니다.

Python supports two pairs of attribute handlers; a type that supports attributes only needs to implement the functions for one pair. The difference is that one pair takes the name of the attribute as a char*, while the other accepts a PyObject*. Each type can use whichever pair makes more sense for the implementation’s convenience.

getattrfunc  tp_getattr;        /* char * version */
setattrfunc  tp_setattr;
/* ... */
getattrofunc tp_getattro;       /* PyObject * version */
setattrofunc tp_setattro;

If accessing attributes of an object is always a simple operation (this will be explained shortly), there are generic implementations which can be used to provide the PyObject* version of the attribute management functions. The actual need for type-specific attribute handlers almost completely disappeared starting with Python 2.2, though there are many examples which have not been updated to use some of the new generic mechanism that is available.

3.3.1. 범용 어트리뷰트 관리

대부분의 확장형은 간단한 어트리뷰트만 사용합니다. 그렇다면, 어트리뷰트를 간단하게 만드는 것은 무엇입니까? 충족해야 하는 몇 가지 조건만 있습니다:

PyType_Ready()가 호출될 때 어트리뷰트의 이름을 알아야 합니다.

어트리뷰트를 찾거나 설정했음을 기록하는 데 특별한 처리가 필요하지 않으며 값을 기반으로 조처를 하지 않아도 됩니다.

이 목록은 어트리뷰트 값, 값을 계산하는 시점 또는 관련 데이터가 저장되는 방법에 제한을 두지 않음에 유의하십시오.

PyType_Ready()가 호출될 때, 형 객체가 참조하는 3개의 테이블을 사용하여 형 객체의 딕셔너리에 배치되는 디스크립터를 만듭니다. 각 디스크립터는 인스턴스 객체의 한 어트리뷰트에 대한 액세스를 제어합니다. 각 테이블은 선택적입니다; 세 개 모두가 NULL이면, 형의 인스턴스는 베이스형에서 상속된 어트리뷰트만 갖게 되며, tp_getattro와 tp_setattro 필드도 NULL로 남겨두어야 베이스형이 어트리뷰트를 처리할 수 있습니다.

테이블은 형 객체의 세 필드로 선언됩니다:

struct PyMethodDef *tp_methods;
struct PyMemberDef *tp_members;
struct PyGetSetDef *tp_getset;

tp_methods가 NULL이 아니면, PyMethodDef 구조체의 배열을 참조해야 합니다. 테이블의 각 항목은 다음 구조체의 인스턴스입니다:

typedef struct PyMethodDef {
    const char  *ml_name;       /* method name */
    PyCFunction  ml_meth;       /* implementation function */
    int          ml_flags;      /* flags */
    const char  *ml_doc;        /* docstring */
} PyMethodDef;

One entry should be defined for each method provided by the type; no entries are needed for methods inherited from a base type. One additional entry is needed at the end; it is a sentinel that marks the end of the array. The ml_name field of the sentinel must be NULL.

두 번째 테이블은 인스턴스에 저장된 데이터에 직접 매핑되는 어트리뷰트를 정의하는 데 사용됩니다. 다양한 기본 C형이 지원되며, 액세스는 읽기 전용이거나 읽고 쓰기일 수 있습니다. 테이블의 구조체는 다음과 같이 정의됩니다:

typedef struct PyMemberDef {
    const char *name;
    int         type;
    int         offset;
    int         flags;
    const char *doc;
} PyMemberDef;

For each entry in the table, a descriptor will be constructed and added to the type which will be able to extract a value from the instance structure. The type field should contain a type code like Py_T_INT or Py_T_DOUBLE; the value will be used to determine how to convert Python values to and from C values. The flags field is used to store flags which control how the attribute can be accessed: you can set it to Py_READONLY to prevent Python code from setting it.

An interesting advantage of using the tp_members table to build descriptors that are used at runtime is that any attribute defined this way can have an associated doc string simply by providing the text in the table. An application can use the introspection API to retrieve the descriptor from the class object, and get the doc string using its __doc__ attribute.

As with the tp_methods table, a sentinel entry with a ml_name value of NULL is required.

3.3.2. 형별 어트리뷰트 관리

For simplicity, only the char* version will be demonstrated here; the type of the name parameter is the only difference between the char* and PyObject* flavors of the interface. This example effectively does the same thing as the generic example above, but does not use the generic support added in Python 2.2. It explains how the handler functions are called, so that if you do need to extend their functionality, you’ll understand what needs to be done.

The tp_getattr handler is called when the object requires an attribute look-up. It is called in the same situations where the __getattr__() method of a class would be called.

예는 다음과 같습니다:

static PyObject *
newdatatype_getattr(newdatatypeobject *obj, char *name)
{
    if (strcmp(name, "data") == 0)
    {
        return PyLong_FromLong(obj->data);
    }

    PyErr_Format(PyExc_AttributeError,
                 "'%.100s' object has no attribute '%.400s'",
                 Py_TYPE(obj)->tp_name, name);
    return NULL;
}

The tp_setattr handler is called when the __setattr__() or __delattr__() method of a class instance would be called. When an attribute should be deleted, the third parameter will be NULL. Here is an example that simply raises an exception; if this were really all you wanted, the tp_setattr handler should be set to NULL.

static int
newdatatype_setattr(newdatatypeobject *obj, char *name, PyObject *v)
{
    PyErr_Format(PyExc_RuntimeError, "Read-only attribute: %s", name);
    return -1;
}

3.4. 객체 비교

richcmpfunc tp_richcompare;

The tp_richcompare handler is called when comparisons are needed. It is analogous to the rich comparison methods, like __lt__(), and also called by PyObject_RichCompare() and PyObject_RichCompareBool().

This function is called with two Python objects and the operator as arguments, where the operator is one of Py_EQ, Py_NE, Py_LE, Py_GE, Py_LT or Py_GT. It should compare the two objects with respect to the specified operator and return Py_True or Py_False if the comparison is successful, Py_NotImplemented to indicate that comparison is not implemented and the other object’s comparison method should be tried, or NULL if an exception was set.

내부 포인터의 크기가 같으면 같다고 간주하는 데이터형에 대한 샘플 구현은 다음과 같습니다:

static PyObject *
newdatatype_richcmp(newdatatypeobject *obj1, newdatatypeobject *obj2, int op)
{
    PyObject *result;
    int c, size1, size2;

    /* code to make sure that both arguments are of type
       newdatatype omitted */

    size1 = obj1->obj_UnderlyingDatatypePtr->size;
    size2 = obj2->obj_UnderlyingDatatypePtr->size;

    switch (op) {
    case Py_LT: c = size1 <  size2; break;
    case Py_LE: c = size1 <= size2; break;
    case Py_EQ: c = size1 == size2; break;
    case Py_NE: c = size1 != size2; break;
    case Py_GT: c = size1 >  size2; break;
    case Py_GE: c = size1 >= size2; break;
    }
    result = c ? Py_True : Py_False;
    Py_INCREF(result);
    return result;
 }

3.5. 추상 프로토콜 지원

파이썬은 다양한 추상 ‘프로토콜’을 지원합니다; 이러한 인터페이스를 사용하기 위해 제공되는 구체적인 인터페이스는 추상 객체 계층에 설명되어 있습니다.

이러한 추상 인터페이스 중 다수는 파이썬 구현 개발 초기에 정의되었습니다. 특히, 숫자, 매핑 및 시퀀스 프로토콜은 처음부터 파이썬의 일부였습니다. 다른 프로토콜은 시간이 지남에 따라 추가되었습니다. 형 구현의 여러 처리기 루틴에 의존하는 프로토콜의 경우, 이전 프로토콜은 형 객체가 참조하는 선택적 처리기 블록으로 정의되었습니다. 최신 프로토콜의 경우 메인 형 객체에 추가 슬롯이 있으며, 슬롯이 존재하고 인터프리터가 확인해야 함을 나타내는 플래그 비트가 설정됩니다. (플래그 비트는 슬롯 값이 NULL이 아님을 나타내지 않습니다. 플래그는 슬롯의 존재를 나타내도록 설정될 수 있지만, 슬롯은 여전히 채워지지 않을 수 있습니다.)

PyNumberMethods   *tp_as_number;
PySequenceMethods *tp_as_sequence;
PyMappingMethods  *tp_as_mapping;

여러분의 객체가 숫자, 시퀀스 또는 매핑 객체처럼 작동하도록 하려면, C형 PyNumberMethods, PySequenceMethods 또는 PyMappingMethods를 각각 구현하는 구조체의 주소를 배치합니다. 이 구조체를 적절한 값으로 채우는 것은 여러분의 책임입니다. 파이썬 소스 배포의 Objects 디렉터리에서 이들 각각의 사용 예를 찾을 수 있습니다.

hashfunc tp_hash;

여러분이 제공하기로 선택했다면, 이 함수는 데이터형의 인스턴스에 대한 해시 숫자를 반환해야 합니다. 다음은 간단한 예입니다:

static Py_hash_t
newdatatype_hash(newdatatypeobject *obj)
{
    Py_hash_t result;
    result = obj->some_size + 32767 * obj->some_number;
    if (result == -1)
       result = -2;
    return result;
}

Py_hash_t는 플랫폼에 따라 변하는 너비의 부호 있는 정수 형입니다. tp_hash에서 -1을 반환하면 에러를 표시해서, 위와 같이 해시 계산에 성공했을 때 반환하지 않도록 주의해야 합니다.

ternaryfunc tp_call;

이 함수는 데이터형의 인스턴스가 “호출”될 때 호출됩니다, 예를 들어, obj1이 데이터형의 인스턴스이고 파이썬 스크립트에 obj1('hello')가 포함되어 있으면 tp_call 처리기가 호출됩니다.

이 함수는 세 개의 인자를 취합니다:

self는 호출의 대상인 데이터형의 인스턴스입니다. 호출이 obj1('hello')이면, self는 obj1입니다.

args는 호출에 대한 인자를 포함하는 튜플입니다. PyArg_ParseTuple()을 사용하여 인자를 추출할 수 있습니다.

kwds는 전달된 키워드 인자의 딕셔너리입니다. 이것이 NULL이 아니고 키워드 인자를 지원하면 PyArg_ParseTupleAndKeywords()를 사용하여 인자를 추출하십시오. 키워드 인자를 지원하지 않고 이것이 NULL이 아니면, 키워드 인자가 지원되지 않는다는 메시지와 함께 TypeError를 발생시키십시오.

장난감 tp_call 구현은 다음과 같습니다:

static PyObject *
newdatatype_call(newdatatypeobject *obj, PyObject *args, PyObject *kwds)
{
    PyObject *result;
    const char *arg1;
    const char *arg2;
    const char *arg3;

    if (!PyArg_ParseTuple(args, "sss:call", &arg1, &arg2, &arg3)) {
        return NULL;
    }
    result = PyUnicode_FromFormat(
        "Returning -- value: [%d] arg1: [%s] arg2: [%s] arg3: [%s]\n",
        obj->obj_UnderlyingDatatypePtr->size,
        arg1, arg2, arg3);
    return result;
}

/* Iterators */
getiterfunc tp_iter;
iternextfunc tp_iternext;

These functions provide support for the iterator protocol. Both handlers take exactly one parameter, the instance for which they are being called, and return a new reference. In the case of an error, they should set an exception and return NULL. tp_iter corresponds to the Python __iter__() method, while tp_iternext corresponds to the Python __next__() method.

모든 이터러블 객체는 이터레이터 객체를 반환해야 하는 tp_iter 처리기를 구현해야 합니다. 다음은 파이썬 클래스에도 적용되는 공통 지침입니다:

여러 개의 독립 이터레이터를 지원할 수 있는 컬렉션(가령 리스트와 튜플)의 경우, tp_iter를 호출할 때마다 새 이터레이터가 만들어지고 반환되어야 합니다.

한 번만 이터레이트 될 수 있는 (보통 파일 객체처럼 이터레이션의 부작용으로 인해) 객체는 스스로에 대한 새로운 참조를 반환하여 tp_iter를 구현할 수 있습니다 – 따라서 tp_iternext 처리기도 구현해야 합니다.

모든 이터레이터 객체는 tp_iter와 tp_iternext를 모두 구현해야 합니다. 이터레이터의 tp_iter 처리기는 이터레이터에 대한 새로운 참조를 반환해야 합니다. tp_iternext 처리기는 이터레이션의 다음 객체(있다면)에 대한 새 참조를 반환해야 합니다. 이터레이션이 끝에 도달하면, tp_iternext는 예외를 설정하지 않고 NULL을 반환하거나, NULL을 반환하는 것에 더해 StopIteration을 설정할 수 있습니다; 예외를 피하면 성능이 약간 향상될 수 있습니다. 실제 에러가 발생하면, tp_iternext는 항상 예외를 설정하고, NULL을 반환해야 합니다.

3.6. 약한 참조 지원

파이썬의 약한 참조 구현의 목표 중 하나는 성능에 중요한 객체(가령 숫자)에 대한 부하를 발생시키지 않고 모든 형이 약한 참조 메커니즘에 참여할 수 있도록 하는 것입니다.

더 보기

weakref 모듈에 대한 설명서.

For an object to be weakly referenceable, the extension type must set the Py_TPFLAGS_MANAGED_WEAKREF bit of the tp_flags field. The legacy tp_weaklistoffset field should be left as zero.

Concretely, here is how the statically declared type object would look:

static PyTypeObject TrivialType = {
    PyVarObject_HEAD_INIT(NULL, 0)
    /* ... other members omitted for brevity ... */
    .tp_flags = Py_TPFLAGS_MANAGED_WEAKREF | ...,
};

The only further addition is that tp_dealloc needs to clear any weak references (by calling PyObject_ClearWeakRefs()):

static void
Trivial_dealloc(TrivialObject *self)
{
    /* Clear weakrefs first before calling any destructors */
    PyObject_ClearWeakRefs((PyObject *) self);
    /* ... remainder of destruction code omitted for brevity ... */
    Py_TYPE(self)->tp_free((PyObject *) self);
}

3.7. 추가 제안

새 데이터형에 특정 메서드를 구현하는 방법을 배우려면, CPython 소스 코드를 구하십시오. Objects 디렉터리로 이동한 다음, C 소스 파일에서 tp_에 원하는 기능을 더한 것(예를 들어, tp_richcompare)을 검색하십시오. 구현하려는 함수의 예를 찾을 수 있을 겁니다.

객체가 구현 중인 형의 구상 인스턴스인지 확인해야 하면, PyObject_TypeCheck() 함수를 사용하십시오. 사용 예는 다음과 같습니다:

if (!PyObject_TypeCheck(some_object, &MyType)) {
    PyErr_SetString(PyExc_TypeError, "arg #1 not a mything");
    return NULL;
}

더 보기

CPython 소스 릴리스를 다운로드하십시오.

https://www.python.org/downloads/source/

GitHub의 CPython 프로젝트, CPython 소스 코드가 개발되는 곳.

https://github.com/python/cpython

4. C와 C++ 확장 빌드하기

CPython의 C 확장은 초기화 함수를 내보내는 공유 라이브러리입니다 (예를 들어, 리눅스는 .so, 윈도우는 .pyd).

To be importable, the shared library must be available on PYTHONPATH, and must be named after the module name, with an appropriate extension. When using setuptools, the correct filename is generated automatically.

초기화 함수는 다음과 같은 서명을 갖습니다:

PyObject *PyInit_modulename(void)

It returns either a fully initialized module, or a PyModuleDef instance. See C 모듈 초기화 for details.

ASCII로만 이루어진 이름을 가진 모듈의 경우, 함수의 이름을 PyInit_<modulename>이어야 합니다. 여기서 <modulename>을 모듈의 이름으로 치환합니다. 다단계 초기화를 사용할 때 ASCII가 아닌 모듈 이름이 허용됩니다. 이 경우, 초기화 함수 이름은 PyInitU_<modulename>이며 <modulename>은 파이썬의 punycode 인코딩으로 인코딩되고 하이픈을 밑줄로 대체합니다. 파이썬에서:

def initfunc_name(name):
    try:
        suffix = b'_' + name.encode('ascii')
    except UnicodeEncodeError:
        suffix = b'U_' + name.encode('punycode').replace(b'-', b'_')
    return b'PyInit' + suffix

여러 초기화 함수를 정의하여 단일 공유 라이브러리에서 여러 모듈을 내보낼 수 있습니다. 그러나, 이들을 임포트 하려면 심볼릭 링크나 사용자 정의 임포터를 사용해야 합니다. 기본적으로 파일 이름에 해당하는 함수만 발견되기 때문입니다. 자세한 내용은 PEP 489 [https://peps.python.org/pep-0489/]의 “한 라이브러리에 여러 모듈” 절을 참조하십시오.

4.1. Building C and C++ Extensions with setuptools

Python 3.12 and newer no longer come with distutils. Please refer to the setuptools documentation at https://setuptools.readthedocs.io/en/latest/setuptools.html to learn more about how build and distribute C/C++ extensions with setuptools.

5. 윈도우에서 C와 C++ 확장 빌드하기

이 장에서는 Microsoft Visual C++를 사용하여 파이썬 용 윈도우 확장 모듈을 만드는 방법을 간략히 설명하고, 이 확장 모듈의 작동 방식에 대한 보다 자세한 배경 정보를 제공합니다. 설명 자료는 파이썬 확장을 빌드하는 법을 배우는 윈도우 프로그래머와 유닉스와 윈도우 모두에서 성공적으로 빌드 할 수 있는 소프트웨어 제작에 관심이 있는 유닉스 프로그래머 모두에게 유용합니다.

모듈 저자는 확장 모듈을 빌드하는데 이 섹션에서 설명하는 것 대신 distutils 접근 방식을 사용하는 것이 좋습니다. 파이썬을 빌드하는 데 사용된 C 컴파일러가 여전히 필요합니다; 보통 Microsoft Visual C++입니다.

참고

이 장에서는 인코딩된 파이썬 버전 번호를 포함하는 여러 파일 이름을 언급합니다. 이 파일 이름은 XY로 나타낸 버전 번호로 표시됩니다; 실제로, 'X'는 주(major) 버전 번호이고 'Y'는 여러분이 작업 중인 파이썬 배포의 부(minor) 버전 번호입니다. 예를 들어, 파이썬 2.2.1을 사용하면, XY는 실제로는 22가 됩니다.

5.1. 요리책 접근법

There are two approaches to building extension modules on Windows, just as there are on Unix: use the setuptools package to control the build process, or do things manually. The setuptools approach works well for most extensions; documentation on using setuptools to build and package extension modules is available in Building C and C++ Extensions with setuptools. If you find you really need to do things manually, it may be instructive to study the project file for the winsound [https://github.com/python/cpython/tree/main/PCbuild/winsound.vcxproj] standard library module.

5.2. 유닉스와 윈도우의 차이점

유닉스와 윈도우는 코드의 실행시간 로딩에 완전히 다른 패러다임을 사용합니다. 동적으로 로드 할 수 있는 모듈을 빌드하려고 시도하기 전에, 시스템 작동 방식을 알고 있어야 합니다.

유닉스에서, 공유 오브젝트 (.so) 파일은 프로그램에서 사용할 코드와 프로그램에서 찾을 것으로 예상되는 함수와 데이터의 이름을 포함합니다. 파일이 프로그램에 결합할 때, 파일의 코드에 있는 함수와 데이터의 모든 참조가 함수와 데이터가 메모리에 놓이게 되는 프로그램에서의 실제 위치를 가리키도록 변경됩니다. 이것은 기본적으로 링크 작업입니다.

윈도우에서, 동적 연결 라이브러리 (.dll) 파일에는 매달린(dangling) 참조가 없습니다. 대신, 함수나 데이터에 대한 액세스는 참조 테이블(lookup table)을 통해 이루어집니다. 따라서 DLL 코드는 프로그램의 메모리를 참조하도록 실행 시간에 수정될 필요가 없습니다; 대신, 코드는 이미 DLL의 참조 테이블을 사용하고 있고, 실행 시간에 참조 테이블이 함수와 데이터를 가리 키도록 수정됩니다.

유닉스에는, 한가지 유형의 라이브러리 파일(.a) 만 있는데, 여러 오브젝트 파일(.o)의 코드가 포함됩니다. 공유 오브젝트 파일(.so)을 만들기 위한 링크 단계에서, 링커는 식별자가 정의된 위치를 알 수 없음을 발견할 수 있습니다. 링커는 라이브러리의 오브젝트 파일에서 그것들을 찾습니다. 발견하면, 그 오브젝트 파일의 모든 코드를 포함합니다.

윈도우에는, 두 가지 유형의 라이브러리, 정적 라이브러리와 임포트 라이브러리가 있습니다 (둘 다 .lib라고 합니다). 정적 라이브러리는 유닉스 .a 파일과 같습니다; 필요할 때 포함될 코드가 들어 있습니다. 임포트 라이브러리는 기본적으로 특정 식별자가 합법적이고 DLL이 로드될 때 프로그램에 존재하게 된다고 링커를 안심시키기 위해서만 사용됩니다. 따라서 링커는 임포트 라이브러리의 정보를 사용하여 DLL에 포함되지 않은 식별자를 사용하는 참조 테이블을 작성합니다. 응용 프로그램이나 DLL이 링크될 때, 임포트 라이브러리가 만들어질 수 있습니다. 이것은 응용 프로그램이나 DLL의 심볼을 사용하는, 이후의 모든 DLL에 사용해야 합니다.

다른 코드 블록 A를 공유해야 하는, 두 개의 동적 로드 모듈 B와 C를 빌드한다고 가정합니다. 유닉스에서는, B.so와 C.so에 대해 링커로 A.a를 전달하지 않습니다; 전달하면 B와 C가 각각 자신의 복사본을 갖게 되어 두 번 포함하게 됩니다. 윈도우에서는, A.dll를 빌드하면 A.lib도 빌드됩니다. 여러분은 B와 C에 대헤 링커로 A.lib를 전달 합니다. A.lib는 코드를 포함하지 않습니다; 실행 시간에 A의 코드에 액세스하는 데 사용될 정보만 포함합니다.

윈도우에서, 임포트 라이브러리를 사용하는 것은 import spam을 사용하는 것과 비슷합니다; 이것은 스팸의 이름에 액세스할 수 있도록 하지만, 별도의 복사본을 만들지는 않습니다. 유닉스에서, 라이브러리와 링크하는 것은 from spam import *와 더 비슷합니다; 별도의 복사본을 만듭니다.

5.3. DLL을 실제로 사용하기

Windows Python is built in Microsoft Visual C++; using other compilers may or may not work. The rest of this section is MSVC++ specific.

윈도우에서 DLL을 만들 때, pythonXY.lib를 링커에 전달해야 합니다. 두 개의 DLL, spam과 (spam에 있는 C 함수를 사용하는) ni를 빌드하려면, 다음 명령을 사용할 수 있습니다:

cl /LD /I/python/include spam.c ../libs/pythonXY.lib
cl /LD /I/python/include ni.c spam.lib ../libs/pythonXY.lib

첫 번째 명령은 세 개의 파일을 만들었습니다: spam.obj, spam.dll 및 spam.lib. Spam.dll은 파이썬 함수(가령 PyArg_ParseTuple())를 포함하지 않지만, pythonXY.lib 덕분에 파이썬 코드를 찾는 방법을 알고 있습니다.

두 번째 명령은 ni.dll(그리고 .obj와 .lib)을 만들었습니다. spam과 파이썬 실행 파일에서 필요한 함수를 찾는 방법을 알고 있습니다.

모든 식별자를 참조 테이블로 내보내지는 않습니다. 다른 모듈(파이썬 포함)이 식별자를 볼 수 있게 하려면, void _declspec(dllexport) initspam(void)나 PyObject _declspec(dllexport) *NiGetSpamData(void)처럼 _declspec(dllexport)라고 선언해야 합니다.

Developer Studio will throw in a lot of import libraries that you do not really need, adding about 100K to your executable. To get rid of them, use the Project Settings dialog, Link tab, to specify ignore default libraries. Add the correct msvcrtxx.lib to the list of libraries.

1. 다른 응용 프로그램에 파이썬 내장하기

이전 장에서는 파이썬을 확장하는 방법, 즉 C 함수의 라이브러리를 파이썬에 연결하여 파이썬의 기능을 확장하는 방법에 관해 설명했습니다. 다른 방법도 가능합니다: 파이썬을 내장시켜 C/C++ 응용 프로그램을 풍부하게 만들 수 있습니다. 내장은 C 나 C++가 아닌 파이썬으로 응용 프로그램의 일부 기능을 구현하는 능력을 응용 프로그램에 제공합니다. 이것은 여러 목적으로 사용될 수 있습니다; 한 가지 예는 사용자가 파이썬으로 스크립트를 작성하여 응용 프로그램을 필요에 맞게 조정할 수 있게 하는 것입니다. 일부 기능을 파이썬으로 작성하기가 더 쉽다면 직접 사용할 수도 있습니다.

파이썬을 내장하는 것은 파이썬을 확장하는 것과 유사합니다만, 아주 같지는 않습니다. 차이점은, 파이썬을 확장할 때 응용 프로그램의 주 프로그램은 여전히 파이썬 인터프리터입니다. 반면에 파이썬을 내장하면 주 프로그램은 파이썬과 아무 관련이 없습니다 — 대신 응용 프로그램 일부에서 간혹 파이썬 코드를 실행하기 위해 파이썬 인터프리터를 호출합니다.

그래서 파이썬을 내장한다면, 여러분은 자신의 메인 프로그램을 제공하게 됩니다. 이 메인 프로그램이해야 할 일 중 하나는 파이썬 인터프리터를 초기화하는 것입니다. 최소한, Py_Initialize() 함수를 호출해야 합니다. 파이썬에 명령 줄 인자를 전달하는 선택적 호출이 있습니다. 그런 다음 나중에 응용 프로그램의 어느 부분에서나 인터프리터를 호출할 수 있습니다.

인터프리터를 호출하는 방법에는 여러 가지가 있습니다: 파이썬 문장을 포함하는 문자열을 PyRun_SimpleString()에 전달하거나, stdio 파일 포인터와 파일명(에러 메시지에서의 식별만을 위해)을 PyRun_SimpleFile()에 전달할 수 있습니다. 또한, 이전 장에서 설명한 저수준의 연산을 호출하여 파이썬 객체를 만들고 사용할 수 있습니다.

더 보기

파이썬/C API 레퍼런스 설명서

파이썬의 C 인터페이스에 대한 자세한 내용은 이 매뉴얼에 있습니다. 필요한 정보가 많이 있습니다.

1.1. 매우 고수준의 내장

파이썬을 내장하는 가장 간단한 형태는 매우 고수준의 인터페이스를 사용하는 것입니다. 이 인터페이스는 응용 프로그램과 직접 상호 작용할 필요 없이 파이썬 스크립트를 실행하기 위한 것입니다. 이것은 예를 들어 파일에 대해 어떤 연산을 수행하는 데 사용될 수 있습니다.

#define PY_SSIZE_T_CLEAN
#include <Python.h>

int
main(int argc, char *argv[])
{
    PyStatus status;
    PyConfig config;
    PyConfig_InitPythonConfig(&config);

    /* optional but recommended */
    status = PyConfig_SetBytesString(&config, &config.program_name, argv[0]);
    if (PyStatus_Exception(status)) {
        goto exception;
    }

    status = Py_InitializeFromConfig(&config);
    if (PyStatus_Exception(status)) {
        goto exception;
    }
    PyConfig_Clear(&config);

    PyRun_SimpleString("from time import time,ctime\n"
                       "print('Today is', ctime(time()))\n");
    if (Py_FinalizeEx() < 0) {
        exit(120);
    }
    return 0;

  exception:
     PyConfig_Clear(&config);
     Py_ExitStatusException(status);
}

참고

#define PY_SSIZE_T_CLEAN was used to indicate that Py_ssize_t should be used in some APIs instead of int. It is not necessary since Python 3.13, but we keep it here for backward compatibility. See 문자열과 버퍼 for a description of this macro.

Setting PyConfig.program_name should be called before Py_InitializeFromConfig() to inform the interpreter about paths to Python run-time libraries. Next, the Python interpreter is initialized with Py_Initialize(), followed by the execution of a hard-coded Python script that prints the date and time. Afterwards, the Py_FinalizeEx() call shuts the interpreter down, followed by the end of the program. In a real program, you may want to get the Python script from another source, perhaps a text-editor routine, a file, or a database. Getting the Python code from a file can better be done by using the PyRun_SimpleFile() function, which saves you the trouble of allocating memory space and loading the file contents.

1.2. 매우 고수준 내장을 넘어서: 개요

고수준 인터페이스는 응용 프로그램에서 임의의 파이썬 코드를 실행할 수 있는 능력을 제공하지만, 최소한 데이터 값을 교환하는 것이 꽤 번거롭습니다. 그러길 원한다면 저수준의 호출을 사용해야 합니다. 더 많은 C 코드를 작성해야 하는 대신, 거의 모든 것을 달성할 수 있습니다.

파이썬을 확장하는 것과 파이썬을 내장하는 것은 다른 의도에도 불구하고 꽤 똑같은 활동이라는 점에 유의해야 합니다. 이전 장에서 논의된 대부분 주제는 여전히 유효합니다. 이것을 보시려면, 파이썬에서 C로의 확장 코드가 실제로 하는 일을 생각해보십시오:

데이터값을 파이썬에서 C로 변환하고,

변환된 값을 사용하여 C 루틴으로 함수 호출을 수행하고,

그 호출에서 얻은 데이터값을 C에서 파이썬으로 변환합니다.

파이썬을 내장할 때, 인터페이스 코드는 다음을 수행합니다:

데이터값을 C에서 파이썬으로 변환하고,

변환된 값을 사용하여 파이썬 인터페이스 루틴으로 함수 호출을 수행하고,

그 호출에서 얻은 데이터 값을 파이썬에서 C로 변환합니다.

보시다시피, 데이터 변환 단계가 언어 간 전송의 다른 방향을 수용하기 위해 단순히 교환됩니다. 유일한 차이점은 두 데이터 변환 간에 호출하는 루틴입니다. 확장할 때는 C 루틴을 호출하고, 내장할 때는 파이썬 루틴을 호출합니다.

이 장에서는 파이썬에서 C로 데이터를 변환하는 방법과 그 반대로 데이터를 변환하는 방법에 관해서는 설명하지 않습니다. 또한, 참조의 올바른 사용과 에러를 다루는 것을 이해하고 있다고 가정합니다. 이러한 측면은 인터프리터를 확장하는 것과 다르지 않으므로, 이전 장에서 필요한 정보를 참조할 수 있습니다.

1.3. 순수한 내장

첫 번째 프로그램은 파이썬 스크립트에 있는 함수를 실행하는 것을 목표로 합니다. 매우 고수준의 인터페이스에 관한 절에서와같이, 파이썬 인터프리터는 애플리케이션과 직접 상호 작용하지 않습니다 (하지만 다음 절에서 바뀔 것입니다).

파이썬 스크립트에서 정의된 함수를 실행하는 코드는 다음과 같습니다:

#define PY_SSIZE_T_CLEAN
#include <Python.h>

int
main(int argc, char *argv[])
{
    PyObject *pName, *pModule, *pFunc;
    PyObject *pArgs, *pValue;
    int i;

    if (argc < 3) {
        fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
        return 1;
    }

    Py_Initialize();
    pName = PyUnicode_DecodeFSDefault(argv[1]);
    /* Error checking of pName left out */

    pModule = PyImport_Import(pName);
    Py_DECREF(pName);

    if (pModule != NULL) {
        pFunc = PyObject_GetAttrString(pModule, argv[2]);
        /* pFunc is a new reference */

        if (pFunc && PyCallable_Check(pFunc)) {
            pArgs = PyTuple_New(argc - 3);
            for (i = 0; i < argc - 3; ++i) {
                pValue = PyLong_FromLong(atoi(argv[i + 3]));
                if (!pValue) {
                    Py_DECREF(pArgs);
                    Py_DECREF(pModule);
                    fprintf(stderr, "Cannot convert argument\n");
                    return 1;
                }
                /* pValue reference stolen here: */
                PyTuple_SetItem(pArgs, i, pValue);
            }
            pValue = PyObject_CallObject(pFunc, pArgs);
            Py_DECREF(pArgs);
            if (pValue != NULL) {
                printf("Result of call: %ld\n", PyLong_AsLong(pValue));
                Py_DECREF(pValue);
            }
            else {
                Py_DECREF(pFunc);
                Py_DECREF(pModule);
                PyErr_Print();
                fprintf(stderr,"Call failed\n");
                return 1;
            }
        }
        else {
            if (PyErr_Occurred())
                PyErr_Print();
            fprintf(stderr, "Cannot find function \"%s\"\n", argv[2]);
        }
        Py_XDECREF(pFunc);
        Py_DECREF(pModule);
    }
    else {
        PyErr_Print();
        fprintf(stderr, "Failed to load \"%s\"\n", argv[1]);
        return 1;
    }
    if (Py_FinalizeEx() < 0) {
        return 120;
    }
    return 0;
}

이 코드는 argv[1]를 사용하여 파이썬 스크립트를 로드하고, argv[2]에서 명명된 함수를 호출합니다. 정수 인자는 argv 배열의 남은 값들입니다. 이 프로그램을 컴파일하고 링크하면 (완성된 실행 파일을 call이라고 부릅시다), 다음과 같은 파이썬 스크립트를 실행하는 데 사용합니다:

def multiply(a,b):
    print("Will compute", a, "times", b)
    c = 0
    for i in range(0, a):
        c = c + b
    return c

그러면 결과는 다음과 같아야 합니다:

$ call multiply multiply 3 2
Will compute 3 times 2
Result of call: 6

프로그램이 기능보다 상당히 큰 편이지만, 대부분 코드는 파이썬과 C 사이의 데이터 변환과 에러 보고를 위한 것입니다. 파이썬 내장과 관련된 흥미로운 부분은 다음처럼 시작합니다

Py_Initialize();
pName = PyUnicode_DecodeFSDefault(argv[1]);
/* Error checking of pName left out */
pModule = PyImport_Import(pName);

인터프리터를 초기화한 후, 스크립트는 PyImport_Import()를 사용하여 로드됩니다. 이 루틴은 인자로 파이썬 문자열을 요구하는데, PyUnicode_FromString() 데이터 변환 루틴을 사용하여 구성됩니다.

pFunc = PyObject_GetAttrString(pModule, argv[2]);
/* pFunc is a new reference */

if (pFunc && PyCallable_Check(pFunc)) {
    ...
}
Py_XDECREF(pFunc);

일단 스크립트가 로드되면, 우리가 찾고 있는 이름이 PyObject_GetAttrString()를 사용하여 검색됩니다. 이름이 존재하고, 반환된 객체가 콜러블이면, 그것이 함수라고 안전하게 가정할 수 있습니다. 그런 다음 프로그램은 인자의 튜플을 일반적인 방법으로 구성하여 진행합니다. 그런 다음 파이썬 함수 호출은 이렇게 이루어집니다:

pValue = PyObject_CallObject(pFunc, pArgs);

함수가 반환되면, pValue는 NULL이거나 함수의 반환 값에 대한 참조를 포함합니다. 값을 검토한 후 참조를 해제해야 합니다.

1.4. 내장된 파이썬을 확장하기

지금까지 내장된 파이썬 인터프리터는 애플리케이션 자체의 기능에 액세스할 수 없었습니다. 파이썬 API는 내장된 인터프리터를 확장함으로써 이것을 허용합니다. 즉, 내장된 인터프리터는 응용 프로그램에서 제공하는 루틴으로 확장됩니다. 복잡하게 들리지만, 그렇게 나쁘지는 않습니다. 잠시 응용 프로그램이 파이썬 인터프리터를 시작한다는 것을 잊어버리십시오. 대신, 응용 프로그램을 서브 루틴의 집합으로 간주하고, 일반 파이썬 확장을 작성하는 것처럼 파이썬에서 해당 루틴에 액세스할 수 있도록 연결 코드를 작성하십시오. 예를 들면:

static int numargs=0;

/* Return the number of arguments of the application command line */
static PyObject*
emb_numargs(PyObject *self, PyObject *args)
{
    if(!PyArg_ParseTuple(args, ":numargs"))
        return NULL;
    return PyLong_FromLong(numargs);
}

static PyMethodDef EmbMethods[] = {
    {"numargs", emb_numargs, METH_VARARGS,
     "Return the number of arguments received by the process."},
    {NULL, NULL, 0, NULL}
};

static PyModuleDef EmbModule = {
    PyModuleDef_HEAD_INIT, "emb", NULL, -1, EmbMethods,
    NULL, NULL, NULL, NULL
};

static PyObject*
PyInit_emb(void)
{
    return PyModule_Create(&EmbModule);
}

위의 코드를 main() 함수 바로 위에 삽입하십시오. 또한, Py_Initialize()에 대한 호출 전에 다음 두 문장을 삽입하십시오:

numargs = argc;
PyImport_AppendInittab("emb", &PyInit_emb);

These two lines initialize the numargs variable, and make the emb.numargs() function accessible to the embedded Python interpreter. With these extensions, the Python script can do things like

import emb
print("Number of arguments", emb.numargs())

실제 응용 프로그램에서, 이 방법은 응용 프로그램의 API를 파이썬에 노출합니다.

1.5. C++로 파이썬 내장하기

파이썬을 C++ 프로그램에 내장하는 것도 가능합니다; 이것이 어떻게 수행되는지는 사용된 C++ 시스템의 세부 사항에 달려 있습니다; 일반적으로 C++로 메인 프로그램을 작성하고, C++ 컴파일러를 사용하여 프로그램을 컴파일하고 링크해야 합니다. C++을 사용하여 파이썬 자체를 다시 컴파일할 필요는 없습니다.

1.6. 유닉스 계열 시스템에서 컴파일과 링크하기

파이썬 인터프리터를 응용 프로그램에 내장하기 위해 컴파일러(와 링커)에 적절한 플래그를 찾는 것이 늘 간단하지는 않습니다. 특히, 특히 파이썬이 자신에게 링크된 C 동적 확장(.so 파일)으로 구현된 라이브러리 모듈을 로드해야 하기 때문입니다.

필요한 컴파일러와 링커 플래그를 찾으려면, 설치 절차의 일부로 생성된 pythonX.Y-config 스크립트를 실행할 수 있습니다 (python3-config 스크립트도 사용 가능할 수 있습니다). 이 스크립트에는 여러 옵션이 있으며, 다음과 같은 것들은 여러분에 직접 유용할 것입니다:

pythonX.Y-config --cflags는 컴파일 할 때의 권장 플래그를 제공합니다:

$ /opt/bin/python3.11-config --cflags
-I/opt/include/python3.11 -I/opt/include/python3.11 -Wsign-compare  -DNDEBUG -g -fwrapv -O3 -Wall

pythonX.Y-config --ldflags --embed will give you the recommended flags when linking:

$ /opt/bin/python3.11-config --ldflags --embed
-L/opt/lib/python3.11/config-3.11-x86_64-linux-gnu -L/opt/lib -lpython3.11 -lpthread -ldl  -lutil -lm

참고

여러 파이썬 설치 간의 (특히 시스템 파이썬과 여러분이 직접 컴파일한 파이썬 간의) 혼란을 피하려면, 위의 예와 같이 pythonX.Y-config의 절대 경로를 사용하는 것이 좋습니다.

이 절차가 여러분을 위해 작동하지 않는다면 (모든 유닉스 계열 플랫폼에서 작동하는 것은 보장되지 않습니다; 하지만, 버그 보고를 환영합니다), 동적 링크에 관한 시스템의 설명서를 읽는 것과/이나 파이썬의 Makefile과 (그 위치를 찾으려면 sysconfig.get_makefile_filename()를 사용하십시오) 컴파일 옵션을 검사해야 합니다. 이때, sysconfig 모듈은 여러분이 결합하려는 구성 값을 프로그래밍 방식으로 추출하는 데 유용한 도구입니다. 예를 들어:

>>> import sysconfig
>>> sysconfig.get_config_var('LIBS')
'-lpthread -ldl  -lutil'
>>> sysconfig.get_config_var('LINKFORSHARED')
'-Xlinker -export-dynamic'

파이썬/C API 레퍼런스 설명서

이 설명서는 확장 모듈을 작성하거나 파이썬을 내장하고자 하는 C와 C++ 프로그래머가 사용하는 API에 관해 설명합니다. 이 설명서와 쌍을 이루는 파이썬 인터프리터 확장 및 내장 는 확장 제작의 일반 원칙을 설명하지만, API 함수를 자세하게 설명하지는 않습니다.

소개

코딩 표준

인클루드 파일

유용한 매크로들

객체, 형 그리고 참조 횟수

예외

파이썬 임베딩하기

디버깅 빌드

C API Stability

Unstable C API

안정적인 응용 프로그램 바이너리 인터페이스

Platform Considerations

Contents of Limited API

매우 고수준 계층

참조 횟수

예외 처리

인쇄와 지우기

예외 발생시키기

경고 발행하기

에러 표시기 조회하기

시그널 처리하기

예외 클래스

예외 객체

유니코드 예외 객체

재귀 제어

표준 예외

표준 경고 범주

유틸리티

운영 체제 유틸리티

시스템 함수

프로세스 제어

모듈 임포트 하기

데이터 마샬링 지원

인자 구문 분석과 값 구축

문자열 변환과 포매팅

PyHash API

리플렉션

코덱 등록소와 지원 함수

PyTime C API

Support for Perf Maps

추상 객체 계층

객체 프로토콜

호출 프로토콜

숫자 프로토콜

시퀀스 프로토콜

매핑 프로토콜

이터레이터 프로토콜

버퍼 프로토콜

구상 객체 계층

기본 객체

숫자 객체

시퀀스 객체

컨테이너 객체

함수 객체

기타 객체

초기화, 파이널리제이션 및 스레드

파이썬 초기화 전

전역 구성 변수

인터프리터 초기화와 파이널리제이션

프로세스 전체 매개 변수

스레드 상태와 전역 인터프리터 록

서브 인터프리터 지원

비동기 알림

프로파일링과 추적

Reference tracing

고급 디버거 지원

스레드 로컬 저장소 지원

Synchronization Primitives

파이썬 초기화 구성

PyConfig C API

PyInitConfig C API

Runtime Python configuration API

Py_GetArgcArgv()

다단계 초기화 비공개 잠정적 API

메모리 관리

개요

Allocator Domains

원시 메모리 인터페이스

메모리 인터페이스

객체 할당자

기본 메모리 할당자

메모리 할당자 사용자 정의

Debug hooks on the Python memory allocators

pymalloc 할당자

The mimalloc allocator

tracemalloc C API

예

객체 구현 지원

힙에 객체 할당하기

공통 객체 구조체

형 객체

순환 가비지 수집 지원

API와 ABI 버전 붙이기

Monitoring C API

Generating Execution Events

Managing the Monitoring State

소개

파이썬의 애플리케이션 프로그래머용 인터페이스는 다양한 수준에서 C/C++ 프로그래머에게 파이썬 인터프리터에 대한 접근 방법을 제공합니다. 이 API는 C++에서도 동일하게 사용 가능하지만 간결함을 위해 보통 파이썬/C API 로 불립니다. 파이썬/C API를 사용하는 데에는 근본적으로 다른 두 가지 이유가 있습니다. 첫번째 이유는 특정한 목적을 위해 확장 모듈을 작성하기 위해서입니다; 이 확장 모듈들은 파이썬 인터프리터를 확장하는 C 모듈들입니다. 이것이 아마도 가장 흔한 용도일 것입니다. 두번째 이유는 파이썬을 더 큰 애플리케이션의 컴포넌트로 사용하기 위함입니다. 이 기술은 일반적으로 파이썬을 애플리케이션에 임베딩(embedding) 하는 것을 말합니다.

확장 모듈을 작성하는 것은 비교적 잘 다듬어진 과정으로, “쿡북” 접근법이 잘 통하며 프로세스를 다소 자동화하는 툴들도 존재합니다. 사람들은 파이썬이 존재한 초기부터 다른 애플리케이션에 파이썬을 임베드 해왔으나 파이썬을 임베딩 하는 과정은 확장 모듈을 작성하는 것보다 복잡합니다.

많은 API 함수들은 파이썬을 임베딩하거나 확장하는 것에 무관하게 유용합니다. 더욱이 파이썬을 임베드하는 대부분의 애플리케이션은 커스텀 확장을 제공할 필요성이 있기 때문에 파이썬을 임베드하려고 시도하기 전에 확장을 작성하는 것에 친숙해지는 것이 좋습니다.

코딩 표준

CPython 에 포함하기 위해 C 코드를 작성하는 경우에는 PEP 7 [https://peps.python.org/pep-0007/] 에 정의된 지침과 표준을 따라야 합니다. 이 지침은 기여하고 있는 파이썬 버전과 상관없이 적용됩니다. 최종적으로 파이썬에 기여하는 것을 기대하지 않는 이상 이 규칙을 따르는 것은 제삼자 확장 모듈에는 필수가 아닙니다.

인클루드 파일

파이썬/C API를 사용하기 위한 모든 함수, 타입 그리고 매크로 정의는 다음 행에 의해 인클루드됩니다.

#define PY_SSIZE_T_CLEAN
#include <Python.h>

이는 다음과 같은 표준 헤더를 인클루드하는것을 의미합니다: <stdio.h>, <string.h>, <errno.h>, <limits.h>, <assert.h> 그리고 <stdlib.h> (사용 가능한 경우).

참고

파이썬은 일부 시스템의 표준 헤더에 영향을 미치는 전처리기 정의를 정의할 수 있으므로 표준 헤더를 인클루드하기 전에 Python.h 를 인클루드해야 합니다.

Python.h 를 인클루드하기 전에 항상 PY_SSIZE_T_CLEAN 를 정의하는 것을 권장합니다. 이 매크로에 대한 자세한 사항은 인자 구문 분석과 값 구축 을 참조하십시오.

Python.h로 정의된 사용자에게 공개되는 모든 이름들은 (포함된 표준 헤더로 정의된 것은 제외) Py 또는 _Py 로 시작하는 이름을 가지고 있습니다. _Py 로 시작하는 이름들은 파이썬 구현에 의해 내부적으로 사용되며 확장 개발자들에 의해 사용돠어서는 안됩니다. 구조체 멤버들은 이름에 접두사가 붙지 않습니다.

참고

사용자 코드는 Py 또는 _Py 로 시작하는 이름들을 정의해서는 안됩니다. 이것은 읽는 사람을 혼란스럽게 하며이러한 접두사가 붙는 추가적인 이름을 정의할수도 있는 향후의 파이썬 버전에 대한 사용자 코드의 이식성을 위태롭게 합니다.

The header files are typically installed with Python. On Unix, these are located in the directories prefix/include/pythonversion/ and exec_prefix/include/pythonversion/, where prefix and exec_prefix are defined by the corresponding parameters to Python’s configure script and version is '%d.%d' % sys.version_info[:2]. On Windows, the headers are installed in prefix/include, where prefix is the installation directory specified to the installer.

To include the headers, place both directories (if different) on your compiler’s search path for includes. Do not place the parent directories on the search path and then use #include <pythonX.Y/Python.h>; this will break on multi-platform builds since the platform independent headers under prefix include the platform specific headers from exec_prefix.

C++ 사용자들은 파이썬/C API 가 C 만을 사용하여 정의되었어도 헤더 파일들이 extern "C" 로 진입점을 제대로 선언한다는 점에 유의해야 합니다. C++ 에서 파이썬/C API 를 사용하기 위해 특별한 조치를 취할 필요는 없습니다.

유용한 매크로들

파이썬 헤더 파일에는 몇 가지 유용한 매크로가 정의되어 있습니다. 대부분은 필요한 곳에 가깝게 정의되어 있습니다. (예를 들어 Py_RETURN_NONE) 나머지 더 일반적인 유틸리티들은 여기에 정의되어 있습니다. 아래 목록이 전체 목록은 아닙니다.

PyMODINIT_FUNC

Declare an extension module PyInit initialization function. The function return type is PyObject*. The macro declares any special linkage declarations required by the platform, and for C++ declares the function as extern "C".

The initialization function must be named PyInit_name, where name is the name of the module, and should be the only non-static item defined in the module file. Example:

static struct PyModuleDef spam_module = {
    PyModuleDef_HEAD_INIT,
    .m_name = "spam",
    ...
};

PyMODINIT_FUNC
PyInit_spam(void)
{
    return PyModule_Create(&spam_module);
}

Py_ABS(x)

x 의 절댓값을 반환합니다.

Added in version 3.3.

Py_ALWAYS_INLINE

Ask the compiler to always inline a static inline function. The compiler can ignore it and decides to not inline the function.

It can be used to inline performance critical static inline functions when building Python in debug mode with function inlining disabled. For example, MSC disables function inlining when building in debug mode.

Marking blindly a static inline function with Py_ALWAYS_INLINE can result in worse performances (due to increased code size for example). The compiler is usually smarter than the developer for the cost/benefit analysis.

If Python is built in debug mode (if the Py_DEBUG macro is defined), the Py_ALWAYS_INLINE macro does nothing.

It must be specified before the function return type. Usage:

static inline Py_ALWAYS_INLINE int random(void) { return 4; }

Added in version 3.11.

Py_CHARMASK(c)

인자는 문자 또는 [-128, 127] 나 [0, 255] 사이의 정수여야 합니다. 이 매크로는 unsigned char 로 캐스팅된 c 를 반환합니다

Py_DEPRECATED(version)

폐지(deprecated) 선언에 사용하십시오. 이 매크로는 심볼 이름 앞에 위치해야 합니다

예제:

Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);

버전 3.8에서 변경: MSVC 지원을 추가했습니다.

Py_GETENV(s)

Like getenv(s), but returns NULL if -E was passed on the command line (see PyConfig.use_environment).

Py_MAX(x, y)

x 와 y 사이의 최댓값을 반환합니다.

Added in version 3.3.

Py_MEMBER_SIZE(type, member)

(type) 구조체의 member 의 크기를 바이트로 반환합니다.

Added in version 3.6.

Py_MIN(x, y)

x 와 y 사이의 최솟값을 반환합니다.

Added in version 3.3.

Py_NO_INLINE

Disable inlining on a function. For example, it reduces the C stack consumption: useful on LTO+PGO builds which heavily inline code (see bpo-33720 [https://bugs.python.org/issue?@action=redirect&bpo=33720]).

Usage:

Py_NO_INLINE static int random(void) { return 4; }

Added in version 3.11.

Py_STRINGIFY(x)

x 를 C 문자열로 변환합니다. 예를 들어 Py_STRINGIFY(123) 은 "123" 을 반환합니다.

Added in version 3.4.

Py_UNREACHABLE()

의도적으로 도달할 수 없는 코드 경로가 있을 경우에 이 매크로를 사용하십시오. 예를 들어, switch 문에서 가능한 모든 값이 case 절에서 다뤄지는 경우에 default: 절에서 사용할 수 있습니다. assert(0) 또는 abort() 대신 사용하십시오.

릴리즈 모드에서 이 매크로는 컴파일러가 코드를 최적화하는데 도움이 되며 도달할 수 없는 코드에 대한 경고를 방지합니다. 예를 들어, 이 매크로는 릴리즈 모드에서 GCC의 __builtin_unreachable() 로 구현됩니다.

Py_UNREACHABLE() 의 용도는 반환하지 않지만 _Py_NO_RETURN 을 선언하지 않은 함수를 호출하는 것입니다

코드 경로가 매우 가능성이 낮지만 예외적인 경우에 도달할 수 있는 경우, 이 매크로를 사용해서는 안됩니다. 예를 들어, 메모리가 부족하거나 시스템 콜이 예상 범위를 벗어나는 값을 반환했을 경우에는 호출자에게 에러를 보고하는 것이 좋습니다. 호출자에게 에러를 보고할 수 없는 경우 Py_FatalError() 를 사용할 수 있습니다.

Added in version 3.7.

Py_UNUSED(arg)

함수의 미사용 인자에 사용하여 컴파일러 경고를 무시합니다. 예시: int func(int a, int Py_UNUSED(b)) { return a; }.

Added in version 3.4.

PyDoc_STRVAR(name, str)

독스트링에서 사용 가능한 name 이란 이름의 변수를 생성합니다. 파이썬이 독스트링 없이 빌드되었다면 변수의 값은 비어있을 것입니다.

PEP 7 [https://peps.python.org/pep-0007/] 에 명시된 것처럼 파이썬을 독스트링 없이 빌드하기 위해 PyDoc_STRVAR 를 독스트링에 사용하십시오

예제:

PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");

static PyMethodDef deque_methods[] = {
    // ...
    {"pop", (PyCFunction)deque_pop, METH_NOARGS, pop_doc},
    // ...
}

PyDoc_STR(str)

주어진 문자열에 대한 독스트링을 생성합니다. 독스트링이 비활성화 되어있을 경우엔 빈 문자열을 생성합니다.

PEP 7 [https://peps.python.org/pep-0007/] 에 명시된 것처럼 독스트링 없이 파이썬을 빌드할 수 있도록 독스트링을 명시할 때 PyDoc_STR 을 사용하십시오.

예제:

static PyMethodDef pysqlite_row_methods[] = {
    {"keys", (PyCFunction)pysqlite_row_keys, METH_NOARGS,
        PyDoc_STR("Returns the keys of the row.")},
    {NULL, NULL}
};

객체, 형 그리고 참조 횟수

Most Python/C API functions have one or more arguments as well as a return value of type PyObject*. This type is a pointer to an opaque data type representing an arbitrary Python object. Since all Python object types are treated the same way by the Python language in most situations (e.g., assignments, scope rules, and argument passing), it is only fitting that they should be represented by a single C type. Almost all Python objects live on the heap: you never declare an automatic or static variable of type PyObject, only pointer variables of type PyObject* can be declared. The sole exception are the type objects; since these must never be deallocated, they are typically static PyTypeObject objects.

모든 파이썬 객체는 (파이썬 정수조차도) 형(type) 과 참조 횟수(reference count) 를 가지고 있습니다. 객체의 형은 객체의 종류를 결정합니다. (예를 들어 정수, 리스트, 또는 사용자 정의 함수 등. 표준형 계층 에 추가적인 형들에 대해 설명되어 있습니다.) 잘 알려진 형에는 객체가 해당 형인지를 확인하는 매크로가 있습니다. 예를 들어 PyList_Check(a) 는 a 가 가리키는 객체가 파이썬 리스트일 경우에만 참입니다.

참조 횟수

The reference count is important because today’s computers have a finite (and often severely limited) memory size; it counts how many different places there are that have a strong reference to an object. Such a place could be another object, or a global (or static) C variable, or a local variable in some C function. When the last strong reference to an object is released (i.e. its reference count becomes zero), the object is deallocated. If it contains references to other objects, those references are released. Those other objects may be deallocated in turn, if there are no more references to them, and so on. (There’s an obvious problem with objects that reference each other here; for now, the solution is “don’t do that.”)

Reference counts are always manipulated explicitly. The normal way is to use the macro Py_INCREF() to take a new reference to an object (i.e. increment its reference count by one), and Py_DECREF() to release that reference (i.e. decrement the reference count by one). The Py_DECREF() macro is considerably more complex than the incref one, since it must check whether the reference count becomes zero and then cause the object’s deallocator to be called. The deallocator is a function pointer contained in the object’s type structure. The type-specific deallocator takes care of releasing references for other objects contained in the object if this is a compound object type, such as a list, as well as performing any additional finalization that’s needed. There’s no chance that the reference count can overflow; at least as many bits are used to hold the reference count as there are distinct memory locations in virtual memory (assuming sizeof(Py_ssize_t) >= sizeof(void*)). Thus, the reference count increment is a simple operation.

It is not necessary to hold a strong reference (i.e. increment the reference count) for every local variable that contains a pointer to an object. In theory, the object’s reference count goes up by one when the variable is made to point to it and it goes down by one when the variable goes out of scope. However, these two cancel each other out, so at the end the reference count hasn’t changed. The only real reason to use the reference count is to prevent the object from being deallocated as long as our variable is pointing to it. If we know that there is at least one other reference to the object that lives at least as long as our variable, there is no need to take a new strong reference (i.e. increment the reference count) temporarily. An important situation where this arises is in objects that are passed as arguments to C functions in an extension module that are called from Python; the call mechanism guarantees to hold a reference to every argument for the duration of the call.

However, a common pitfall is to extract an object from a list and hold on to it for a while without taking a new reference. Some other operation might conceivably remove the object from the list, releasing that reference, and possibly deallocating it. The real danger is that innocent-looking operations may invoke arbitrary Python code which could do this; there is a code path which allows control to flow back to the user from a Py_DECREF(), so almost any operation is potentially dangerous.

A safe approach is to always use the generic operations (functions whose name begins with PyObject_, PyNumber_, PySequence_ or PyMapping_). These operations always create a new strong reference (i.e. increment the reference count) of the object they return. This leaves the caller with the responsibility to call Py_DECREF() when they are done with the result; this soon becomes second nature.

참조 횟수 상세

The reference count behavior of functions in the Python/C API is best explained in terms of ownership of references. Ownership pertains to references, never to objects (objects are not owned: they are always shared). “Owning a reference” means being responsible for calling Py_DECREF on it when the reference is no longer needed. Ownership can also be transferred, meaning that the code that receives ownership of the reference then becomes responsible for eventually releasing it by calling Py_DECREF() or Py_XDECREF() when it’s no longer needed—or passing on this responsibility (usually to its caller). When a function passes ownership of a reference on to its caller, the caller is said to receive a new reference. When no ownership is transferred, the caller is said to borrow the reference. Nothing needs to be done for a borrowed reference.

반대로 호출 함수에게 객체에 대한 참조를 넘길 때는 두가지 가능성이 있습니다: 함수는 객체에 대한 참조를 훔칠 수도, 그러지 않을 수도 있습니다. 참조를 훔치는 것은 함수에 참조를 전달할 때 해당 함수가 전달된 참조를 소유한다고 가정하고 더 이상 책임을 지지 않는다는 것을 의미합니다.

참조를 훔치는 함수는 거의 없습니다. 주목할만한 두가지 예외는 PyList_SetItem() 과 PyTuple_SetItem() 입니다. 이 두가지 함수는 요소에 대한 참조를 훔칩니다(단, 요소를 넣을 튜플이나 리스트에 대한 참조는 훔치지 않습니다.). 이 함수들은 새로 만들어진 객체들로 튜플이나 리스트를 채우는 일반적인 관행 때문에 참조를 훔치도록 설계되었습니다. 예를 들어, 튜플을 만드는 코드 (1, 2, "three") 는 다음과 같을 수 있습니다. (잠시 에러 처리는 잊어버리십시오. 더 좋은 방법으로 코딩하는 방법은 아래에 나와 있습니다.)

PyObject *t;

t = PyTuple_New(3);
PyTuple_SetItem(t, 0, PyLong_FromLong(1L));
PyTuple_SetItem(t, 1, PyLong_FromLong(2L));
PyTuple_SetItem(t, 2, PyUnicode_FromString("three"));

여기서 PyTuple_SetItem() 는 PyLong_FromLong() 가 반환한 참조를 곧바로 훔칩니다. 객체에 대한 참조가 훔쳐져도 계속 객체를 사용하려면 참조를 훔치는 함수를 호출하기 전에 Py_INCREF() 를 다른 참조를 가져오는데 사용하십시오.

덧붙이자면, PyTuple_SetItem() 은 튜플에 요소를 넣는 유일한 방법입니다. 튜플은 불변 자료형이기 때문에 PySequence_SetItem() 과 PyObject_SetItem() 는 튜플에 요소를 넣는 것을 거부합니다. PyTuple_SetItem() 은 직접 만들고 있는 튜플에만 사용되어야 합니다.

리스트를 채우는 동일한 의미의 코드는 PyList_New() 와 PyList_SetItem() 을 사용해 만들 수 있습니다.

하지만 실제로는 이렇게 튜플 또는 리스트를 만들고 채우는 경우는 드뭅니다. 일반적인 객체들을 형식 문자열(format string)로 지시되는 C 값으로부터 만들어낼 수 있는 제네릭 함수 Py_BuildValue() 가 있습니다. 예룰 들어, 위의 두 블록의 코드를 다음 코드로 대체할 수 있습니다. (에러 검사도 처리합니다.)

PyObject *tuple, *list;

tuple = Py_BuildValue("(iis)", 1, 2, "three");
list = Py_BuildValue("[iis]", 1, 2, "three");

It is much more common to use PyObject_SetItem() and friends with items whose references you are only borrowing, like arguments that were passed in to the function you are writing. In that case, their behaviour regarding references is much saner, since you don’t have to take a new reference just so you can give that reference away (“have it be stolen”). For example, this function sets all items of a list (actually, any mutable sequence) to a given item:

int
set_all(PyObject *target, PyObject *item)
{
    Py_ssize_t i, n;

    n = PyObject_Length(target);
    if (n < 0)
        return -1;
    for (i = 0; i < n; i++) {
        PyObject *index = PyLong_FromSsize_t(i);
        if (!index)
            return -1;
        if (PyObject_SetItem(target, index, item) < 0) {
            Py_DECREF(index);
            return -1;
        }
        Py_DECREF(index);
    }
    return 0;
}

함수 반환 값에 대해서는 상황이 약간 다릅니다. 대부분의 함수에 참조를 전달해도 해당 참조에 대한 소유권 책임이 바뀌진 않지만 객체에 대한 참조를 제공하는 많은 함수는 참조의 소유권을 제공합니다. 이유는 간단합니다. 대부분의 경우에서 반환된 객체는 즉석에서 생성되고 반환된 참조는 객체에 대한 유일한 참조입니다. 따라서 PyObject_GetItem() 과 PySequence_GetItem() 처럼 객체에 대한 참조를 반환하는 제네릭 함수들은 언제나 새로운 참조를 반환합니다 (호출자가 객체의 소유자가 됩니다).

함수의 의해 반환된 함수를 소유하고 있는지는 어떤 함수를 호출하느냐에 따라 달라진다는 것을 아는 것이 중요합니다. — 깃털 (함수에 인자로 전달된 객체의 형) 은 해당되지 않습니다! 따라서 PyList_GetItem() 를 사용하여 리스트에서 항목을 가져오면 참조를 소유하지 않습니다. — 하지만 동일한 인자를 받는 PySequence_GetItem() 를 사용하여 리스트에서 항목을 가져온다면 반환된 객체에 대한 참조를 소유하게 됩니다.

다음은 정수 리스트에 있는 항목의 합계를 구하는 함수를 작성하는 방법의 예시입니다. 한 번은 PyList_GetItem() 를 사용하고, 한 번은 PySequence_GetItem() 을 사용합니다.

long
sum_list(PyObject *list)
{
    Py_ssize_t i, n;
    long total = 0, value;
    PyObject *item;

    n = PyList_Size(list);
    if (n < 0)
        return -1; /* Not a list */
    for (i = 0; i < n; i++) {
        item = PyList_GetItem(list, i); /* Can't fail */
        if (!PyLong_Check(item)) continue; /* Skip non-integers */
        value = PyLong_AsLong(item);
        if (value == -1 && PyErr_Occurred())
            /* Integer too big to fit in a C long, bail out */
            return -1;
        total += value;
    }
    return total;
}

long
sum_sequence(PyObject *sequence)
{
    Py_ssize_t i, n;
    long total = 0, value;
    PyObject *item;
    n = PySequence_Length(sequence);
    if (n < 0)
        return -1; /* Has no length */
    for (i = 0; i < n; i++) {
        item = PySequence_GetItem(sequence, i);
        if (item == NULL)
            return -1; /* Not a sequence, or other failure */
        if (PyLong_Check(item)) {
            value = PyLong_AsLong(item);
            Py_DECREF(item);
            if (value == -1 && PyErr_Occurred())
                /* Integer too big to fit in a C long, bail out */
                return -1;
            total += value;
        }
        else {
            Py_DECREF(item); /* Discard reference ownership */
        }
    }
    return total;
}

형

There are few other data types that play a significant role in the Python/C API; most are simple C types such as int, long, double and char*. A few structure types are used to describe static tables used to list the functions exported by a module or the data attributes of a new object type, and another is used to describe the value of a complex number. These will be discussed together with the functions that use them.

type Py_ssize_t

Part of the Stable ABI.

A signed integral type such that sizeof(Py_ssize_t) == sizeof(size_t). C99 doesn’t define such a thing directly (size_t is an unsigned integral type). See PEP 353 [https://peps.python.org/pep-0353/] for details. PY_SSIZE_T_MAX is the largest positive value of type Py_ssize_t.

예외

파이썬 프로그래머는 특정한 에러 처리가 필요할 경우에만 에러를 처리하면 됩니다. 처리되지 않은 예외는 사용자에게 전달되는 최상위 인터프리터까지 스택 트레이스백과 함께 자동으로 호출자, 호출자의 호출자 등으로 전파됩니다.

그러나 C 프로그래머들에게 에러 검사는 항상 명시적이어야만 합니다. 파이썬/C API의 모든 함수는 해당 함수의 문서에서 명시하지 않는 한 예외를 발생시킬 수 있습니다. 일반적으로 함수에 에러가 발생하면 함수는 예외를 설정하고 소유하고 있는 모든 객체에 대한 참조를 취소하고 에러 표시기를 반환합니다. 달리 문서화되지 않은 경우 표시기는 함수의 반환 형에 따라 NULL 또는 -1 입니다. 일부 함수는 에러를 의미하는 거짓과 함께 참/거짓의 불리언 결과를 반환합니다. 아주 일부의 함수는 명시적인 에러 표시기가 없거나 모호한 반환값을 가지며 PyErr_Occurred() 를 사용하여 명시적인 점검을 요구합니다. 이런 예외는 항상 명시적으로 문서화됩니다.

예외 상태는 스레드 별 공간에서 관리됩니다. (스레드를 사용하지 않는 프로그램에서는 전역 공간을 사용한다는 말과 같습니다.) 스레드는 예외가 발생했거나, 발생하지 않았거나의 두가지 상태 중 하나일 수 있습니다. 함수 PyErr_Occurred() 는 이 상태를 확인하기 위해 사용할 수 있습니다. 해당 함수는 예외가 발생했을 경우 예외 형 객체에 대한 빌린 참조를 반환합니다. 예외가 발생하지 않았을 경우엔 NULL 을 반환합니다. 예외 상태를 설정하기 위한 여러가지 함수들이 있습니다: PyErr_SetString() 는 예외 상태를 설정하기 위해 가장 보편적인 (가장 일반적인 것은 아니지만) 함수입니다. PyErr_Clear() 는 예외 상태를 지웁니다.

전체 예외 상태는 예외 형, 해당 예외 값, 트레이스백이라는 세가지 객체로 구성됩니다. (셋 모두 NULL 일 수 있습니다.) 이 세가지 객체는 파이썬의 sys.exc_info() 의 결과와 같은 의미를 가지고 있지만 동일하지는 않습니다. 파이썬 객체는 try … except 문으로 처리되는 마지막 예외를 표현하는 반면 C 수준 예외는 sys.exc_info() 와 그 친구들로 예외를 전송하는 파이썬 바이트코드 인터프리터의 메인 루프에 도달할 때까지 C 함수들 간에 전달되는 동안에만 존재합니다.

파이썬 1.5부터 선호되어 온 파이썬 코드에서의 스레드 안전한 예외 상태 접근 방법은 파이썬 코드를 위해 스레드 별 예외 상태를 반환하는 sys.exc_info() 함수를 호출하는 것입니다. 또한 예외 상태에 접근하는 양쪽 방법의 의미도 바뀌어 에러를 포착하는 함수가 호출자의 예외 상태를 보존하기 위해 스레드의 예외를 저장하고 복원합니다. 이는 평범해 보이는 함수가 처리중인 예외를 덮어씌우는 것으로 인한 예외 처리 코드의 흔한 버그를 방지합니다. 또한 트레이스백의 스택 프레임에 의하여 참조되는 객체들에 대해 종종 원하지 않은 수명 증가가 일어나는 것을 방지합니다

일반적으로 어떤 작업을 수행하기 위해 다른 함수를 호출하는 함수는 호출된 함수가 예외를 일으켰는지 확인해야만 하며 만약 예외가 일어났다면 호출자에게 예외 상태를 전달해야 합니다. 소유하고 있는 모든 객체에 대한 참조를 버리고 에러 표시기를 반환해야 하지만 다른 예외를 설정해서는 안됩니다. — 방금 일어난 예외를 덮어씌우고 정확한 에러 원인에 대한 중요한 정보를 잃어버리게 됩니다.

A simple example of detecting exceptions and passing them on is shown in the sum_sequence() example above. It so happens that this example doesn’t need to clean up any owned references when it detects an error. The following example function shows some error cleanup. First, to remind you why you like Python, we show the equivalent Python code:

def incr_item(dict, key):
    try:
        item = dict[key]
    except KeyError:
        item = 0
    dict[key] = item + 1

다음은 같은 의미의 웅장한 C 코드입니다:

int
incr_item(PyObject *dict, PyObject *key)
{
    /* Objects all initialized to NULL for Py_XDECREF */
    PyObject *item = NULL, *const_one = NULL, *incremented_item = NULL;
    int rv = -1; /* Return value initialized to -1 (failure) */

    item = PyObject_GetItem(dict, key);
    if (item == NULL) {
        /* Handle KeyError only: */
        if (!PyErr_ExceptionMatches(PyExc_KeyError))
            goto error;

        /* Clear the error and use zero: */
        PyErr_Clear();
        item = PyLong_FromLong(0L);
        if (item == NULL)
            goto error;
    }
    const_one = PyLong_FromLong(1L);
    if (const_one == NULL)
        goto error;

    incremented_item = PyNumber_Add(item, const_one);
    if (incremented_item == NULL)
        goto error;

    if (PyObject_SetItem(dict, key, incremented_item) < 0)
        goto error;
    rv = 0; /* Success */
    /* Continue with cleanup code */

 error:
    /* Cleanup code, shared by success and failure path */

    /* Use Py_XDECREF() to ignore NULL references */
    Py_XDECREF(item);
    Py_XDECREF(const_one);
    Py_XDECREF(incremented_item);

    return rv; /* -1 for error, 0 for success */
}

이 예시는 C goto 문의 허용된 사용방법을 보여줍니다! 이 예시는 특정한 예외를 처리하기 위한 PyErr_ExceptionMatches() 와 PyErr_Clear() 의 사용 방법과 Py_XDECREF() 를 사용하여 소유하고 있는 NULL 일 수도 있는 참조를 삭제하는 방법을 표현합니다. (이름에 있는 'X' 를 주목하십시오. Py_DECREF() 는 NULL 참조와 마주치면 충돌을 일으킵니다.) 이 예시를 수행하려면 소유하고 있는 참조를 보유하는데 사용하는 변수를 NULL 로 초기화하는 것이 중요합니다. 마찬가지로 반환 값은 -1 (실패) 로 설정되고 마지만 호출이 성공한 뒤에야 성공으로 설정됩니다.

파이썬 임베딩하기

확장 작성자들과는 달리 파이썬 인터프리터를 임베딩 하는 사람들만이 걱정해야 하는 한가지 중요한 문제는 파이썬 인터프리터의 초기화, 그리고 아마도 마무리일 것입니다. 인터프리터의 대부분의 기능은 인터프리터가 초기화 된 이후에 사용할 수 있습니다.

기본적인 초기화 함수는 Py_Initialize() 입니다. 이 함수는 로드된 모듈 테이블을 초기화 하고 기본 모듈인 builtins, __main__, 그리고 sys 를 생성합니다. 또한 모듈 검색 경로 (sys.path) 를 초기화합니다

Py_Initialize() does not set the “script argument list” (sys.argv). If this variable is needed by Python code that will be executed later, setting PyConfig.argv and PyConfig.parse_argv must be set: see Python Initialization Configuration.

대부분의 시스템에서 (특별히 유닉스와 윈도우는 세부적인 부분이 조금 다르긴 하지만) Py_Initialize() 는 파이썬 인터프리터를 기준으로 고정된 위치에 파이썬 라이브러리가 있다고 가정하여 표준 파이썬 인터프리터 실행 파일에 대한 최선의 추측을 바탕으로 바탕으로 모듈 검색 경로를 계산합니다. 특히 셸 명령어 검색 경로 (환경 변수 PATH) 에서 python 이라는 이름의 실행 파일이 발견되는 부모 디렉터리를 기준으로 lib/pythonX.Y 같은 이름을 가진 디렉터리를 찾습니다.

예를 들어 파이썬 실행 파일이 /usr/local/bin/python 에서 발견된다면 라이브러리는 /usr/local/lib/pythonX.Y 에 있는 것으로 가정합니다. (실제로 이 특정 경로는 PATH 를 따라 python 이라는 이름의 실행 파일이 발견되지 않을 때 사용되는 “fallback” 경로이기도 합니다.) 유저는 환경 변수 PYTHONHOME 를 설정하여 이 동작을 재정의하거나 PYTHONPATH 를 설정하여 표준 경로 앞에 추가적인 디렉터리를 추가할 수 있습니다.

The embedding application can steer the search by setting PyConfig.program_name before calling Py_InitializeFromConfig(). Note that PYTHONHOME still overrides this and PYTHONPATH is still inserted in front of the standard path. An application that requires total control has to provide its own implementation of Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix(), and Py_GetProgramFullPath() (all defined in Modules/getpath.c).

가끔은 파이썬을 “uninitialize” 하는 것이 바람직합니다. 예를 들어 애플리케이션이 다시 시작하거나 (Py_Initialize() 다시 호출하기) 애플리케이션에서 파이썬의 사용이 끝나 파이썬이 할당한 메모리를 해제하려고 할 수 있습니다. Py_FinalizeEx() 를 호출하여 이를 달성할 수 있습니다. 함수 Py_IsInitialized() 는 파이썬이 현재 초기화된 상태에 있을 경우 참을 반환합니다. 이 함수들에 대한 자세한 내용은 다른 장에서 제공됩니다. Py_FinalizeEx() 가 파이썬 인터프리터가 할당한 모든 메모리를 해제하지는 않는다는 점에 유의해야 합니다. 예를 들어, 현재 확장 모듈에서 할당한 메모리는 해제할 수 없습니다.

디버깅 빌드

파이썬은 인터프리터와 확장 모듈들에 대한 추가적인 검사를 가능하게 하는 여러 매크로를 사용하여 빌드될 수 있습니다. 이러한 검사는 런타임에 많은 오버헤드를 추가하는 경향이 있으므로 기본적으로 실행되지 않습니다.

A full list of the various types of debugging builds is in the file Misc/SpecialBuilds.txt in the Python source distribution. Builds are available that support tracing of reference counts, debugging the memory allocator, or low-level profiling of the main interpreter loop. Only the most frequently used builds will be described in the remainder of this section.

Py_DEBUG

Compiling the interpreter with the Py_DEBUG macro defined produces what is generally meant by a debug build of Python. Py_DEBUG is enabled in the Unix build by adding --with-pydebug to the ./configure command. It is also implied by the presence of the not-Python-specific _DEBUG macro. When Py_DEBUG is enabled in the Unix build, compiler optimization is disabled.

In addition to the reference count debugging described below, extra checks are performed, see Python Debug Build.

Defining Py_TRACE_REFS enables reference tracing (see the configure --with-trace-refs option). When defined, a circular doubly linked list of active objects is maintained by adding two extra fields to every PyObject. Total allocations are tracked as well. Upon exit, all existing references are printed. (In interactive mode this happens after every statement run by the interpreter.)

자세한 내용은 파이썬 소스 배포판 안의 Misc/SpecialBuilds.txt 를 참조하십시오.

C API Stability

Unless documented otherwise, Python’s C API is covered by the Backwards Compatibility Policy, PEP 387 [https://peps.python.org/pep-0387/]. Most changes to it are source-compatible (typically by only adding new API). Changing existing API or removing API is only done after a deprecation period or to fix serious issues.

CPython’s Application Binary Interface (ABI) is forward- and backwards-compatible across a minor release (if these are compiled the same way; see Platform Considerations below). So, code compiled for Python 3.10.0 will work on 3.10.8 and vice versa, but will need to be compiled separately for 3.9.x and 3.11.x.

There are two tiers of C API with different stability expectations:

Unstable API, may change in minor versions without a deprecation period. It is marked by the PyUnstable prefix in names.

Limited API, is compatible across several minor releases. When Py_LIMITED_API is defined, only this subset is exposed from Python.h.

These are discussed in more detail below.

Names prefixed by an underscore, such as _Py_InternalState, are private API that can change without notice even in patch releases. If you need to use this API, consider reaching out to CPython developers [https://discuss.python.org/c/core-dev/c-api/30] to discuss adding public API for your use case.

Unstable C API

Any API named with the PyUnstable prefix exposes CPython implementation details, and may change in every minor release (e.g. from 3.9 to 3.10) without any deprecation warnings. However, it will not change in a bugfix release (e.g. from 3.10.0 to 3.10.1).

It is generally intended for specialized, low-level tools like debuggers.

Projects that use this API are expected to follow CPython development and spend extra effort adjusting to changes.

안정적인 응용 프로그램 바이너리 인터페이스

For simplicity, this document talks about extensions, but the Limited API and Stable ABI work the same way for all uses of the API – for example, embedding Python.

Limited C API

Python 3.2 introduced the Limited API, a subset of Python’s C API. Extensions that only use the Limited API can be compiled once and work with multiple versions of Python. Contents of the Limited API are listed below.

Py_LIMITED_API

Define this macro before including Python.h to opt in to only use the Limited API, and to select the Limited API version.

Define Py_LIMITED_API to the value of PY_VERSION_HEX corresponding to the lowest Python version your extension supports. The extension will work without recompilation with all Python 3 releases from the specified one onward, and can use Limited API introduced up to that version.

Rather than using the PY_VERSION_HEX macro directly, hardcode a minimum minor version (e.g. 0x030A0000 for Python 3.10) for stability when compiling with future Python versions.

You can also define Py_LIMITED_API to 3. This works the same as 0x03020000 (Python 3.2, the version that introduced Limited API).

Stable ABI

To enable this, Python provides a Stable ABI: a set of symbols that will remain compatible across Python 3.x versions.

The Stable ABI contains symbols exposed in the Limited API, but also other ones – for example, functions necessary to support older versions of the Limited API.

On Windows, extensions that use the Stable ABI should be linked against python3.dll rather than a version-specific library such as python39.dll.

On some platforms, Python will look for and load shared library files named with the abi3 tag (e.g. mymodule.abi3.so). It does not check if such extensions conform to a Stable ABI. The user (or their packaging tools) need to ensure that, for example, extensions built with the 3.10+ Limited API are not installed for lower versions of Python.

All functions in the Stable ABI are present as functions in Python’s shared library, not solely as macros. This makes them usable from languages that don’t use the C preprocessor.

Limited API Scope and Performance

The goal for the Limited API is to allow everything that is possible with the full C API, but possibly with a performance penalty.

For example, while PyList_GetItem() is available, its “unsafe” macro variant PyList_GET_ITEM() is not. The macro can be faster because it can rely on version-specific implementation details of the list object.

Without Py_LIMITED_API defined, some C API functions are inlined or replaced by macros. Defining Py_LIMITED_API disables this inlining, allowing stability as Python’s data structures are improved, but possibly reducing performance.

By leaving out the Py_LIMITED_API definition, it is possible to compile a Limited API extension with a version-specific ABI. This can improve performance for that Python version, but will limit compatibility. Compiling with Py_LIMITED_API will then yield an extension that can be distributed where a version-specific one is not available – for example, for prereleases of an upcoming Python version.

Limited API Caveats

Note that compiling with Py_LIMITED_API is not a complete guarantee that code conforms to the Limited API or the Stable ABI. Py_LIMITED_API only covers definitions, but an API also includes other issues, such as expected semantics.

One issue that Py_LIMITED_API does not guard against is calling a function with arguments that are invalid in a lower Python version. For example, consider a function that starts accepting NULL for an argument. In Python 3.9, NULL now selects a default behavior, but in Python 3.8, the argument will be used directly, causing a NULL dereference and crash. A similar argument works for fields of structs.

Another issue is that some struct fields are currently not hidden when Py_LIMITED_API is defined, even though they’re part of the Limited API.

For these reasons, we recommend testing an extension with all minor Python versions it supports, and preferably to build with the lowest such version.

We also recommend reviewing documentation of all used API to check if it is explicitly part of the Limited API. Even with Py_LIMITED_API defined, a few private declarations are exposed for technical reasons (or even unintentionally, as bugs).

Also note that the Limited API is not necessarily stable: compiling with Py_LIMITED_API with Python 3.8 means that the extension will run with Python 3.12, but it will not necessarily compile with Python 3.12. In particular, parts of the Limited API may be deprecated and removed, provided that the Stable ABI stays stable.

Platform Considerations

ABI stability depends not only on Python, but also on the compiler used, lower-level libraries and compiler options. For the purposes of the Stable ABI, these details define a “platform”. They usually depend on the OS type and processor architecture

It is the responsibility of each particular distributor of Python to ensure that all Python versions on a particular platform are built in a way that does not break the Stable ABI. This is the case with Windows and macOS releases from python.org and many third-party distributors.

Contents of Limited API

Currently, the Limited API includes the following items:

PY_VECTORCALL_ARGUMENTS_OFFSET

PyAIter_Check()

PyArg_Parse()

PyArg_ParseTuple()

PyArg_ParseTupleAndKeywords()

PyArg_UnpackTuple()

PyArg_VaParse()

PyArg_VaParseTupleAndKeywords()

PyArg_ValidateKeywordArguments()

PyBaseObject_Type

PyBool_FromLong()

PyBool_Type

PyBuffer_FillContiguousStrides()

PyBuffer_FillInfo()

PyBuffer_FromContiguous()

PyBuffer_GetPointer()

PyBuffer_IsContiguous()

PyBuffer_Release()

PyBuffer_SizeFromFormat()

PyBuffer_ToContiguous()

PyByteArrayIter_Type

PyByteArray_AsString()

PyByteArray_Concat()

PyByteArray_FromObject()

PyByteArray_FromStringAndSize()

PyByteArray_Resize()

PyByteArray_Size()

PyByteArray_Type

PyBytesIter_Type

PyBytes_AsString()

PyBytes_AsStringAndSize()

PyBytes_Concat()

PyBytes_ConcatAndDel()

PyBytes_DecodeEscape()

PyBytes_FromFormat()

PyBytes_FromFormatV()

PyBytes_FromObject()

PyBytes_FromString()

PyBytes_FromStringAndSize()

PyBytes_Repr()

PyBytes_Size()

PyBytes_Type

PyCFunction

PyCFunctionFast

PyCFunctionFastWithKeywords

PyCFunctionWithKeywords

PyCFunction_GetFlags()

PyCFunction_GetFunction()

PyCFunction_GetSelf()

PyCFunction_New()

PyCFunction_NewEx()

PyCFunction_Type

PyCMethod_New()

PyCallIter_New()

PyCallIter_Type

PyCallable_Check()

PyCapsule_Destructor

PyCapsule_GetContext()

PyCapsule_GetDestructor()

PyCapsule_GetName()

PyCapsule_GetPointer()

PyCapsule_Import()

PyCapsule_IsValid()

PyCapsule_New()

PyCapsule_SetContext()

PyCapsule_SetDestructor()

PyCapsule_SetName()

PyCapsule_SetPointer()

PyCapsule_Type

PyClassMethodDescr_Type

PyCodec_BackslashReplaceErrors()

PyCodec_Decode()

PyCodec_Decoder()

PyCodec_Encode()

PyCodec_Encoder()

PyCodec_IgnoreErrors()

PyCodec_IncrementalDecoder()

PyCodec_IncrementalEncoder()

PyCodec_KnownEncoding()

PyCodec_LookupError()

PyCodec_NameReplaceErrors()

PyCodec_Register()

PyCodec_RegisterError()

PyCodec_ReplaceErrors()

PyCodec_StreamReader()

PyCodec_StreamWriter()

PyCodec_StrictErrors()

PyCodec_Unregister()

PyCodec_XMLCharRefReplaceErrors()

PyComplex_FromDoubles()

PyComplex_ImagAsDouble()

PyComplex_RealAsDouble()

PyComplex_Type

PyDescr_NewClassMethod()

PyDescr_NewGetSet()

PyDescr_NewMember()

PyDescr_NewMethod()

PyDictItems_Type

PyDictIterItem_Type

PyDictIterKey_Type

PyDictIterValue_Type

PyDictKeys_Type

PyDictProxy_New()

PyDictProxy_Type

PyDictRevIterItem_Type

PyDictRevIterKey_Type

PyDictRevIterValue_Type

PyDictValues_Type

PyDict_Clear()

PyDict_Contains()

PyDict_Copy()

PyDict_DelItem()

PyDict_DelItemString()

PyDict_GetItem()

PyDict_GetItemRef()

PyDict_GetItemString()

PyDict_GetItemStringRef()

PyDict_GetItemWithError()

PyDict_Items()

PyDict_Keys()

PyDict_Merge()

PyDict_MergeFromSeq2()

PyDict_New()

PyDict_Next()

PyDict_SetItem()

PyDict_SetItemString()

PyDict_Size()

PyDict_Type

PyDict_Update()

PyDict_Values()

PyEllipsis_Type

PyEnum_Type

PyErr_BadArgument()

PyErr_BadInternalCall()

PyErr_CheckSignals()

PyErr_Clear()

PyErr_Display()

PyErr_DisplayException()

PyErr_ExceptionMatches()

PyErr_Fetch()

PyErr_Format()

PyErr_FormatV()

PyErr_GetExcInfo()

PyErr_GetHandledException()

PyErr_GetRaisedException()

PyErr_GivenExceptionMatches()

PyErr_NewException()

PyErr_NewExceptionWithDoc()

PyErr_NoMemory()

PyErr_NormalizeException()

PyErr_Occurred()

PyErr_Print()

PyErr_PrintEx()

PyErr_ProgramText()

PyErr_ResourceWarning()

PyErr_Restore()

PyErr_SetExcFromWindowsErr()

PyErr_SetExcFromWindowsErrWithFilename()

PyErr_SetExcFromWindowsErrWithFilenameObject()

PyErr_SetExcFromWindowsErrWithFilenameObjects()

PyErr_SetExcInfo()

PyErr_SetFromErrno()

PyErr_SetFromErrnoWithFilename()

PyErr_SetFromErrnoWithFilenameObject()

PyErr_SetFromErrnoWithFilenameObjects()

PyErr_SetFromWindowsErr()

PyErr_SetFromWindowsErrWithFilename()

PyErr_SetHandledException()

PyErr_SetImportError()

PyErr_SetImportErrorSubclass()

PyErr_SetInterrupt()

PyErr_SetInterruptEx()

PyErr_SetNone()

PyErr_SetObject()

PyErr_SetRaisedException()

PyErr_SetString()

PyErr_SyntaxLocation()

PyErr_SyntaxLocationEx()

PyErr_WarnEx()

PyErr_WarnExplicit()

PyErr_WarnFormat()

PyErr_WriteUnraisable()

PyEval_AcquireThread()

PyEval_EvalCode()

PyEval_EvalCodeEx()

PyEval_EvalFrame()

PyEval_EvalFrameEx()

PyEval_GetBuiltins()

PyEval_GetFrame()

PyEval_GetFrameBuiltins()

PyEval_GetFrameGlobals()

PyEval_GetFrameLocals()

PyEval_GetFuncDesc()

PyEval_GetFuncName()

PyEval_GetGlobals()

PyEval_GetLocals()

PyEval_InitThreads()

PyEval_ReleaseThread()

PyEval_RestoreThread()

PyEval_SaveThread()

PyExc_ArithmeticError

PyExc_AssertionError

PyExc_AttributeError

PyExc_BaseException

PyExc_BaseExceptionGroup

PyExc_BlockingIOError

PyExc_BrokenPipeError

PyExc_BufferError

PyExc_BytesWarning

PyExc_ChildProcessError

PyExc_ConnectionAbortedError

PyExc_ConnectionError

PyExc_ConnectionRefusedError

PyExc_ConnectionResetError

PyExc_DeprecationWarning

PyExc_EOFError

PyExc_EncodingWarning

PyExc_EnvironmentError

PyExc_Exception

PyExc_FileExistsError

PyExc_FileNotFoundError

PyExc_FloatingPointError

PyExc_FutureWarning

PyExc_GeneratorExit

PyExc_IOError

PyExc_ImportError

PyExc_ImportWarning

PyExc_IndentationError

PyExc_IndexError

PyExc_InterruptedError

PyExc_IsADirectoryError

PyExc_KeyError

PyExc_KeyboardInterrupt

PyExc_LookupError

PyExc_MemoryError

PyExc_ModuleNotFoundError

PyExc_NameError

PyExc_NotADirectoryError

PyExc_NotImplementedError

PyExc_OSError

PyExc_OverflowError

PyExc_PendingDeprecationWarning

PyExc_PermissionError

PyExc_ProcessLookupError

PyExc_RecursionError

PyExc_ReferenceError

PyExc_ResourceWarning

PyExc_RuntimeError

PyExc_RuntimeWarning

PyExc_StopAsyncIteration

PyExc_StopIteration

PyExc_SyntaxError

PyExc_SyntaxWarning

PyExc_SystemError

PyExc_SystemExit

PyExc_TabError

PyExc_TimeoutError

PyExc_TypeError

PyExc_UnboundLocalError

PyExc_UnicodeDecodeError

PyExc_UnicodeEncodeError

PyExc_UnicodeError

PyExc_UnicodeTranslateError

PyExc_UnicodeWarning

PyExc_UserWarning

PyExc_ValueError

PyExc_Warning

PyExc_WindowsError

PyExc_ZeroDivisionError

PyExceptionClass_Name()

PyException_GetArgs()

PyException_GetCause()

PyException_GetContext()

PyException_GetTraceback()

PyException_SetArgs()

PyException_SetCause()

PyException_SetContext()

PyException_SetTraceback()

PyFile_FromFd()

PyFile_GetLine()

PyFile_WriteObject()

PyFile_WriteString()

PyFilter_Type

PyFloat_AsDouble()

PyFloat_FromDouble()

PyFloat_FromString()

PyFloat_GetInfo()

PyFloat_GetMax()

PyFloat_GetMin()

PyFloat_Type

PyFrameObject

PyFrame_GetCode()

PyFrame_GetLineNumber()

PyFrozenSet_New()

PyFrozenSet_Type

PyGC_Collect()

PyGC_Disable()

PyGC_Enable()

PyGC_IsEnabled()

PyGILState_Ensure()

PyGILState_GetThisThreadState()

PyGILState_Release()

PyGILState_STATE

PyGetSetDef

PyGetSetDescr_Type

PyImport_AddModule()

PyImport_AddModuleObject()

PyImport_AddModuleRef()

PyImport_AppendInittab()

PyImport_ExecCodeModule()

PyImport_ExecCodeModuleEx()

PyImport_ExecCodeModuleObject()

PyImport_ExecCodeModuleWithPathnames()

PyImport_GetImporter()

PyImport_GetMagicNumber()

PyImport_GetMagicTag()

PyImport_GetModule()

PyImport_GetModuleDict()

PyImport_Import()

PyImport_ImportFrozenModule()

PyImport_ImportFrozenModuleObject()

PyImport_ImportModule()

PyImport_ImportModuleLevel()

PyImport_ImportModuleLevelObject()

PyImport_ImportModuleNoBlock()

PyImport_ReloadModule()

PyIndex_Check()

PyInterpreterState

PyInterpreterState_Clear()

PyInterpreterState_Delete()

PyInterpreterState_Get()

PyInterpreterState_GetDict()

PyInterpreterState_GetID()

PyInterpreterState_New()

PyIter_Check()

PyIter_Next()

PyIter_NextItem()

PyIter_Send()

PyListIter_Type

PyListRevIter_Type

PyList_Append()

PyList_AsTuple()

PyList_GetItem()

PyList_GetItemRef()

PyList_GetSlice()

PyList_Insert()

PyList_New()

PyList_Reverse()

PyList_SetItem()

PyList_SetSlice()

PyList_Size()

PyList_Sort()

PyList_Type

PyLongObject

PyLongRangeIter_Type

PyLong_AsDouble()

PyLong_AsInt()

PyLong_AsInt32()

PyLong_AsInt64()

PyLong_AsLong()

PyLong_AsLongAndOverflow()

PyLong_AsLongLong()

PyLong_AsLongLongAndOverflow()

PyLong_AsSize_t()

PyLong_AsSsize_t()

PyLong_AsUInt32()

PyLong_AsUInt64()

PyLong_AsUnsignedLong()

PyLong_AsUnsignedLongLong()

PyLong_AsUnsignedLongLongMask()

PyLong_AsUnsignedLongMask()

PyLong_AsVoidPtr()

PyLong_FromDouble()

PyLong_FromInt32()

PyLong_FromInt64()

PyLong_FromLong()

PyLong_FromLongLong()

PyLong_FromSize_t()

PyLong_FromSsize_t()

PyLong_FromString()

PyLong_FromUInt32()

PyLong_FromUInt64()

PyLong_FromUnsignedLong()

PyLong_FromUnsignedLongLong()

PyLong_FromVoidPtr()

PyLong_GetInfo()

PyLong_Type

PyMap_Type

PyMapping_Check()

PyMapping_GetItemString()

PyMapping_GetOptionalItem()

PyMapping_GetOptionalItemString()

PyMapping_HasKey()

PyMapping_HasKeyString()

PyMapping_HasKeyStringWithError()

PyMapping_HasKeyWithError()

PyMapping_Items()

PyMapping_Keys()

PyMapping_Length()

PyMapping_SetItemString()

PyMapping_Size()

PyMapping_Values()

PyMem_Calloc()

PyMem_Free()

PyMem_Malloc()

PyMem_RawCalloc()

PyMem_RawFree()

PyMem_RawMalloc()

PyMem_RawRealloc()

PyMem_Realloc()

PyMemberDef

PyMemberDescr_Type

PyMember_GetOne()

PyMember_SetOne()

PyMemoryView_FromBuffer()

PyMemoryView_FromMemory()

PyMemoryView_FromObject()

PyMemoryView_GetContiguous()

PyMemoryView_Type

PyMethodDef

PyMethodDescr_Type

PyModuleDef

PyModuleDef_Base

PyModuleDef_Init()

PyModuleDef_Type

PyModule_Add()

PyModule_AddFunctions()

PyModule_AddIntConstant()

PyModule_AddObject()

PyModule_AddObjectRef()

PyModule_AddStringConstant()

PyModule_AddType()

PyModule_Create2()

PyModule_ExecDef()

PyModule_FromDefAndSpec2()

PyModule_GetDef()

PyModule_GetDict()

PyModule_GetFilename()

PyModule_GetFilenameObject()

PyModule_GetName()

PyModule_GetNameObject()

PyModule_GetState()

PyModule_New()

PyModule_NewObject()

PyModule_SetDocString()

PyModule_Type

PyNumber_Absolute()

PyNumber_Add()

PyNumber_And()

PyNumber_AsSsize_t()

PyNumber_Check()

PyNumber_Divmod()

PyNumber_Float()

PyNumber_FloorDivide()

PyNumber_InPlaceAdd()

PyNumber_InPlaceAnd()

PyNumber_InPlaceFloorDivide()

PyNumber_InPlaceLshift()

PyNumber_InPlaceMatrixMultiply()

PyNumber_InPlaceMultiply()

PyNumber_InPlaceOr()

PyNumber_InPlacePower()

PyNumber_InPlaceRemainder()

PyNumber_InPlaceRshift()

PyNumber_InPlaceSubtract()

PyNumber_InPlaceTrueDivide()

PyNumber_InPlaceXor()

PyNumber_Index()

PyNumber_Invert()

PyNumber_Long()

PyNumber_Lshift()

PyNumber_MatrixMultiply()

PyNumber_Multiply()

PyNumber_Negative()

PyNumber_Or()

PyNumber_Positive()

PyNumber_Power()

PyNumber_Remainder()

PyNumber_Rshift()

PyNumber_Subtract()

PyNumber_ToBase()

PyNumber_TrueDivide()

PyNumber_Xor()

PyOS_AfterFork()

PyOS_AfterFork_Child()

PyOS_AfterFork_Parent()

PyOS_BeforeFork()

PyOS_CheckStack()

PyOS_FSPath()

PyOS_InputHook

PyOS_InterruptOccurred()

PyOS_double_to_string()

PyOS_getsig()

PyOS_mystricmp()

PyOS_mystrnicmp()

PyOS_setsig()

PyOS_sighandler_t

PyOS_snprintf()

PyOS_string_to_double()

PyOS_strtol()

PyOS_strtoul()

PyOS_vsnprintf()

PyObject

PyObject.ob_refcnt

PyObject.ob_type

PyObject_ASCII()

PyObject_AsFileDescriptor()

PyObject_Bytes()

PyObject_Call()

PyObject_CallFunction()

PyObject_CallFunctionObjArgs()

PyObject_CallMethod()

PyObject_CallMethodObjArgs()

PyObject_CallNoArgs()

PyObject_CallObject()

PyObject_Calloc()

PyObject_CheckBuffer()

PyObject_ClearWeakRefs()

PyObject_CopyData()

PyObject_DelAttr()

PyObject_DelAttrString()

PyObject_DelItem()

PyObject_DelItemString()

PyObject_Dir()

PyObject_Format()

PyObject_Free()

PyObject_GC_Del()

PyObject_GC_IsFinalized()

PyObject_GC_IsTracked()

PyObject_GC_Track()

PyObject_GC_UnTrack()

PyObject_GenericGetAttr()

PyObject_GenericGetDict()

PyObject_GenericSetAttr()

PyObject_GenericSetDict()

PyObject_GetAIter()

PyObject_GetAttr()

PyObject_GetAttrString()

PyObject_GetBuffer()

PyObject_GetItem()

PyObject_GetIter()

PyObject_GetOptionalAttr()

PyObject_GetOptionalAttrString()

PyObject_GetTypeData()

PyObject_HasAttr()

PyObject_HasAttrString()

PyObject_HasAttrStringWithError()

PyObject_HasAttrWithError()

PyObject_Hash()

PyObject_HashNotImplemented()

PyObject_Init()

PyObject_InitVar()

PyObject_IsInstance()

PyObject_IsSubclass()

PyObject_IsTrue()

PyObject_Length()

PyObject_Malloc()

PyObject_Not()

PyObject_Realloc()

PyObject_Repr()

PyObject_RichCompare()

PyObject_RichCompareBool()

PyObject_SelfIter()

PyObject_SetAttr()

PyObject_SetAttrString()

PyObject_SetItem()

PyObject_Size()

PyObject_Str()

PyObject_Type()

PyObject_Vectorcall()

PyObject_VectorcallMethod()

PyProperty_Type

PyRangeIter_Type

PyRange_Type

PyReversed_Type

PySeqIter_New()

PySeqIter_Type

PySequence_Check()

PySequence_Concat()

PySequence_Contains()

PySequence_Count()

PySequence_DelItem()

PySequence_DelSlice()

PySequence_Fast()

PySequence_GetItem()

PySequence_GetSlice()

PySequence_In()

PySequence_InPlaceConcat()

PySequence_InPlaceRepeat()

PySequence_Index()

PySequence_Length()

PySequence_List()

PySequence_Repeat()

PySequence_SetItem()

PySequence_SetSlice()

PySequence_Size()

PySequence_Tuple()

PySetIter_Type

PySet_Add()

PySet_Clear()

PySet_Contains()

PySet_Discard()

PySet_New()

PySet_Pop()

PySet_Size()

PySet_Type

PySlice_AdjustIndices()

PySlice_GetIndices()

PySlice_GetIndicesEx()

PySlice_New()

PySlice_Type

PySlice_Unpack()

PyState_AddModule()

PyState_FindModule()

PyState_RemoveModule()

PyStructSequence_Desc

PyStructSequence_Field

PyStructSequence_GetItem()

PyStructSequence_New()

PyStructSequence_NewType()

PyStructSequence_SetItem()

PyStructSequence_UnnamedField

PySuper_Type

PySys_Audit()

PySys_AuditTuple()

PySys_FormatStderr()

PySys_FormatStdout()

PySys_GetObject()

PySys_GetXOptions()

PySys_ResetWarnOptions()

PySys_SetArgv()

PySys_SetArgvEx()

PySys_SetObject()

PySys_WriteStderr()

PySys_WriteStdout()

PyThreadState

PyThreadState_Clear()

PyThreadState_Delete()

PyThreadState_Get()

PyThreadState_GetDict()

PyThreadState_GetFrame()

PyThreadState_GetID()

PyThreadState_GetInterpreter()

PyThreadState_New()

PyThreadState_SetAsyncExc()

PyThreadState_Swap()

PyThread_GetInfo()

PyThread_ReInitTLS()

PyThread_acquire_lock()

PyThread_acquire_lock_timed()

PyThread_allocate_lock()

PyThread_create_key()

PyThread_delete_key()

PyThread_delete_key_value()

PyThread_exit_thread()

PyThread_free_lock()

PyThread_get_key_value()

PyThread_get_stacksize()

PyThread_get_thread_ident()

PyThread_get_thread_native_id()

PyThread_init_thread()

PyThread_release_lock()

PyThread_set_key_value()

PyThread_set_stacksize()

PyThread_start_new_thread()

PyThread_tss_alloc()

PyThread_tss_create()

PyThread_tss_delete()

PyThread_tss_free()

PyThread_tss_get()

PyThread_tss_is_created()

PyThread_tss_set()

PyTraceBack_Here()

PyTraceBack_Print()

PyTraceBack_Type

PyTupleIter_Type

PyTuple_GetItem()

PyTuple_GetSlice()

PyTuple_New()

PyTuple_Pack()

PyTuple_SetItem()

PyTuple_Size()

PyTuple_Type

PyTypeObject

PyType_ClearCache()

PyType_Freeze()

PyType_FromMetaclass()

PyType_FromModuleAndSpec()

PyType_FromSpec()

PyType_FromSpecWithBases()

PyType_GenericAlloc()

PyType_GenericNew()

PyType_GetBaseByToken()

PyType_GetFlags()

PyType_GetFullyQualifiedName()

PyType_GetModule()

PyType_GetModuleByDef()

PyType_GetModuleName()

PyType_GetModuleState()

PyType_GetName()

PyType_GetQualName()

PyType_GetSlot()

PyType_GetTypeDataSize()

PyType_IsSubtype()

PyType_Modified()

PyType_Ready()

PyType_Slot

PyType_Spec

PyType_Type

PyUnicodeDecodeError_Create()

PyUnicodeDecodeError_GetEncoding()

PyUnicodeDecodeError_GetEnd()

PyUnicodeDecodeError_GetObject()

PyUnicodeDecodeError_GetReason()

PyUnicodeDecodeError_GetStart()

PyUnicodeDecodeError_SetEnd()

PyUnicodeDecodeError_SetReason()

PyUnicodeDecodeError_SetStart()

PyUnicodeEncodeError_GetEncoding()

PyUnicodeEncodeError_GetEnd()

PyUnicodeEncodeError_GetObject()

PyUnicodeEncodeError_GetReason()

PyUnicodeEncodeError_GetStart()

PyUnicodeEncodeError_SetEnd()

PyUnicodeEncodeError_SetReason()

PyUnicodeEncodeError_SetStart()

PyUnicodeIter_Type

PyUnicodeTranslateError_GetEnd()

PyUnicodeTranslateError_GetObject()

PyUnicodeTranslateError_GetReason()

PyUnicodeTranslateError_GetStart()

PyUnicodeTranslateError_SetEnd()

PyUnicodeTranslateError_SetReason()

PyUnicodeTranslateError_SetStart()

PyUnicode_Append()

PyUnicode_AppendAndDel()

PyUnicode_AsASCIIString()

PyUnicode_AsCharmapString()

PyUnicode_AsDecodedObject()

PyUnicode_AsDecodedUnicode()

PyUnicode_AsEncodedObject()

PyUnicode_AsEncodedString()

PyUnicode_AsEncodedUnicode()

PyUnicode_AsLatin1String()

PyUnicode_AsMBCSString()

PyUnicode_AsRawUnicodeEscapeString()

PyUnicode_AsUCS4()

PyUnicode_AsUCS4Copy()

PyUnicode_AsUTF16String()

PyUnicode_AsUTF32String()

PyUnicode_AsUTF8AndSize()

PyUnicode_AsUTF8String()

PyUnicode_AsUnicodeEscapeString()

PyUnicode_AsWideChar()

PyUnicode_AsWideCharString()

PyUnicode_BuildEncodingMap()

PyUnicode_Compare()

PyUnicode_CompareWithASCIIString()

PyUnicode_Concat()

PyUnicode_Contains()

PyUnicode_Count()

PyUnicode_Decode()

PyUnicode_DecodeASCII()

PyUnicode_DecodeCharmap()

PyUnicode_DecodeCodePageStateful()

PyUnicode_DecodeFSDefault()

PyUnicode_DecodeFSDefaultAndSize()

PyUnicode_DecodeLatin1()

PyUnicode_DecodeLocale()

PyUnicode_DecodeLocaleAndSize()

PyUnicode_DecodeMBCS()

PyUnicode_DecodeMBCSStateful()

PyUnicode_DecodeRawUnicodeEscape()

PyUnicode_DecodeUTF16()

PyUnicode_DecodeUTF16Stateful()

PyUnicode_DecodeUTF32()

PyUnicode_DecodeUTF32Stateful()

PyUnicode_DecodeUTF7()

PyUnicode_DecodeUTF7Stateful()

PyUnicode_DecodeUTF8()

PyUnicode_DecodeUTF8Stateful()

PyUnicode_DecodeUnicodeEscape()

PyUnicode_EncodeCodePage()

PyUnicode_EncodeFSDefault()

PyUnicode_EncodeLocale()

PyUnicode_Equal()

PyUnicode_EqualToUTF8()

PyUnicode_EqualToUTF8AndSize()

PyUnicode_FSConverter()

PyUnicode_FSDecoder()

PyUnicode_Find()

PyUnicode_FindChar()

PyUnicode_Format()

PyUnicode_FromEncodedObject()

PyUnicode_FromFormat()

PyUnicode_FromFormatV()

PyUnicode_FromObject()

PyUnicode_FromOrdinal()

PyUnicode_FromString()

PyUnicode_FromStringAndSize()

PyUnicode_FromWideChar()

PyUnicode_GetDefaultEncoding()

PyUnicode_GetLength()

PyUnicode_InternFromString()

PyUnicode_InternInPlace()

PyUnicode_IsIdentifier()

PyUnicode_Join()

PyUnicode_Partition()

PyUnicode_RPartition()

PyUnicode_RSplit()

PyUnicode_ReadChar()

PyUnicode_Replace()

PyUnicode_Resize()

PyUnicode_RichCompare()

PyUnicode_Split()

PyUnicode_Splitlines()

PyUnicode_Substring()

PyUnicode_Tailmatch()

PyUnicode_Translate()

PyUnicode_Type

PyUnicode_WriteChar()

PyVarObject

PyVarObject.ob_base

PyVarObject.ob_size

PyVectorcall_Call()

PyVectorcall_NARGS()

PyWeakReference

PyWeakref_GetObject()

PyWeakref_GetRef()

PyWeakref_NewProxy()

PyWeakref_NewRef()

PyWrapperDescr_Type

PyWrapper_New()

PyZip_Type

Py_AddPendingCall()

Py_AtExit()

Py_BEGIN_ALLOW_THREADS

Py_BLOCK_THREADS

Py_BuildValue()

Py_BytesMain()

Py_CompileString()

Py_DecRef()

Py_DecodeLocale()

Py_END_ALLOW_THREADS

Py_EncodeLocale()

Py_EndInterpreter()

Py_EnterRecursiveCall()

Py_Exit()

Py_FatalError()

Py_FileSystemDefaultEncodeErrors

Py_FileSystemDefaultEncoding

Py_Finalize()

Py_FinalizeEx()

Py_GenericAlias()

Py_GenericAliasType

Py_GetBuildInfo()

Py_GetCompiler()

Py_GetConstant()

Py_GetConstantBorrowed()

Py_GetCopyright()

Py_GetExecPrefix()

Py_GetPath()

Py_GetPlatform()

Py_GetPrefix()

Py_GetProgramFullPath()

Py_GetProgramName()

Py_GetPythonHome()

Py_GetRecursionLimit()

Py_GetVersion()

Py_HasFileSystemDefaultEncoding

Py_IncRef()

Py_Initialize()

Py_InitializeEx()

Py_Is()

Py_IsFalse()

Py_IsFinalizing()

Py_IsInitialized()

Py_IsNone()

Py_IsTrue()

Py_LeaveRecursiveCall()

Py_Main()

Py_MakePendingCalls()

Py_NewInterpreter()

Py_NewRef()

Py_REFCNT()

Py_ReprEnter()

Py_ReprLeave()

Py_SetProgramName()

Py_SetPythonHome()

Py_SetRecursionLimit()

Py_TYPE()

Py_UCS4

Py_UNBLOCK_THREADS

Py_UTF8Mode

Py_VaBuildValue()

Py_Version

Py_XNewRef()

Py_buffer

Py_intptr_t

Py_ssize_t

Py_uintptr_t

allocfunc

binaryfunc

descrgetfunc

descrsetfunc

destructor

getattrfunc

getattrofunc

getbufferproc

getiterfunc

getter

hashfunc

initproc

inquiry

iternextfunc

lenfunc

newfunc

objobjargproc

objobjproc

releasebufferproc

reprfunc

richcmpfunc

setattrfunc

setattrofunc

setter

ssizeargfunc

ssizeobjargproc

ssizessizeargfunc

ssizessizeobjargproc

symtable

ternaryfunc

traverseproc

unaryfunc

vectorcallfunc

visitproc

매우 고수준 계층

이 장의 함수들은 파일이나 버퍼에 제공된 파이썬 소스 코드를 실행할 수 있도록 하지만, 인터프리터와 더 세밀한 방식으로 상호 작용하도록 하지는 않습니다.

Several of these functions accept a start symbol from the grammar as a parameter. The available start symbols are Py_eval_input, Py_file_input, and Py_single_input. These are described following the functions which accept them as parameters.

Note also that several of these functions take FILE* parameters. One particular issue which needs to be handled carefully is that the FILE structure for different C libraries can be different and incompatible. Under Windows (at least), it is possible for dynamically linked extensions to actually use different libraries, so care should be taken that FILE* parameters are only passed to these functions if it is certain that they were created by the same library that the Python runtime is using.

int PyRun_AnyFile(FILE *fp, const char *filename)

아래 PyRun_AnyFileExFlags() 의 단순화된 인터페이스입니다. closeit은 0으로 flags는 NULL로 설정된 상태로 남겨둡니다.

int PyRun_AnyFileFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)

아래 PyRun_AnyFileExFlags() 의 단순화된 인터페이스입니다. 이것은 closeit 인자를 0으로 설정된 상태로 남겨둡니다.

int PyRun_AnyFileEx(FILE *fp, const char *filename, int closeit)

아래 PyRun_AnyFileExFlags() 의 단순화된 인터페이스입니다. 이것은 flags 인자를 NULL로 설정된 상태로 남겨둡니다.

int PyRun_AnyFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)

If fp refers to a file associated with an interactive device (console or terminal input or Unix pseudo-terminal), return the value of PyRun_InteractiveLoop(), otherwise return the result of PyRun_SimpleFile(). filename is decoded from the filesystem encoding (sys.getfilesystemencoding()). If filename is NULL, this function uses "???" as the filename. If closeit is true, the file is closed before PyRun_SimpleFileExFlags() returns.

int PyRun_SimpleString(const char *command)

This is a simplified interface to PyRun_SimpleStringFlags() below, leaving the PyCompilerFlags* argument set to NULL.

int PyRun_SimpleStringFlags(const char *command, PyCompilerFlags *flags)

flags 인자에 따라 __main__ 모듈에서 command에 있는 파이썬 소스 코드를 실행합니다. __main__이 존재하지 않으면 만듭니다. 성공하면 0을, 예외가 발생하면 -1을 반환합니다. 에러가 있으면, 예외 정보를 얻을 방법이 없습니다. flags의 의미는 아래를 참조하십시오.

Note that if an otherwise unhandled SystemExit is raised, this function will not return -1, but exit the process, as long as PyConfig.inspect is zero.

int PyRun_SimpleFile(FILE *fp, const char *filename)

아래 PyRun_SimpleFileExFlags() 의 단순화된 인터페이스입니다. closeit을 0으로, flags를 NULL로 설정된 상태로 남겨둡니다.

int PyRun_SimpleFileEx(FILE *fp, const char *filename, int closeit)

아래 PyRun_SimpleFileExFlags() 의 단순화된 인터페이스입니다. flags를 NULL로 설정된 상태로 남겨둡니다.

int PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit, PyCompilerFlags *flags)

Similar to PyRun_SimpleStringFlags(), but the Python source code is read from fp instead of an in-memory string. filename should be the name of the file, it is decoded from filesystem encoding and error handler. If closeit is true, the file is closed before PyRun_SimpleFileExFlags() returns.

참고

윈도우에서, fp는 바이너리 모드로 열어야 합니다 (예를 들어 fopen(filename, "rb")). 그렇지 않으면, 파이썬은 LF 줄 종료가 있는 스크립트 파일을 올바르게 처리하지 못할 수 있습니다.

int PyRun_InteractiveOne(FILE *fp, const char *filename)

아래 PyRun_InteractiveOneFlags() 의 단순화된 인터페이스입니다. flags를 NULL로 설정된 상태로 남겨둡니다.

int PyRun_InteractiveOneFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)

Read and execute a single statement from a file associated with an interactive device according to the flags argument. The user will be prompted using sys.ps1 and sys.ps2. filename is decoded from the filesystem encoding and error handler.

입력이 성공적으로 실행될 때 0을, 예외가 있으면 -1을, 또는 구문 분석 에러가 있으면 파이썬의 일부로 배포된 errcode.h 인클루드 파일에 있는 에러 코드를 반환합니다. (errcode.h는 Python.h에서 인클루드하지 않기 때문에 필요하면 특별히 인클루드해야 함에 유의하십시오.)

int PyRun_InteractiveLoop(FILE *fp, const char *filename)

아래 PyRun_InteractiveLoopFlags() 의 단순화된 인터페이스입니다. flags를 NULL로 설정된 상태로 남겨둡니다.

int PyRun_InteractiveLoopFlags(FILE *fp, const char *filename, PyCompilerFlags *flags)

Read and execute statements from a file associated with an interactive device until EOF is reached. The user will be prompted using sys.ps1 and sys.ps2. filename is decoded from the filesystem encoding and error handler. Returns 0 at EOF or a negative number upon failure.

int (*PyOS_InputHook)(void)

Part of the Stable ABI.

프로토타입 int func(void)인 함수를 가리키도록 설정할 수 있습니다. 이 함수는 파이썬의 인터프리터 프롬프트가 유휴 상태가 되고 터미널에서 사용자 입력을 기다리려고 할 때 호출됩니다. 반환 값은 무시됩니다. 이 훅을 재정의하는 것은 파이썬 소스 코드의 Modules/_tkinter.c에서 한 것처럼 인터프리터의 프롬프트를 다른 이벤트 루프와 통합하는 데 사용될 수 있습니다.

버전 3.12에서 변경: This function is only called from the main interpreter.

char *(*PyOS_ReadlineFunctionPointer)(FILE*, FILE*, const char*)

프로토타입 char *func(FILE *stdin, FILE *stdout, char *prompt)인 함수를 가리키도록 설정하여, 인터프리터의 프롬프트에서 단일 입력 줄을 읽는 데 사용되는 기본 함수를 재정의할 수 있습니다. 이 함수는 NULL이 아니면 문자열 prompt를 출력한 다음 제공된 표준 입력 파일에서 입력 줄을 읽고 결과 문자열을 반환할 것이라고 기대됩니다. 예를 들어, readline 모듈은 이 훅을 설정하여 줄 편집과 탭 완성 기능을 제공합니다.

결과는 PyMem_RawMalloc()이나 PyMem_RawRealloc()으로 할당된 문자열 이거나, 에러가 발생했으면 NULL이어야 합니다.

버전 3.4에서 변경: 결과는 PyMem_Malloc()이나 PyMem_Realloc()으로 할당하는 대신, PyMem_RawMalloc()이나 PyMem_RawRealloc()으로 할당해야 합니다.

버전 3.12에서 변경: This function is only called from the main interpreter.

PyObject *PyRun_String(const char *str, int start, PyObject *globals, PyObject *locals)

Return value: New reference.

아래 PyRun_StringFlags()의 단순화된 인터페이스입니다. 이것은 flags를 NULL로 설정된 상태로 남겨둡니다.

PyObject *PyRun_StringFlags(const char *str, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)

Return value: New reference.

flags로 지정된 컴파일러 플래그를 사용하여 globals과 locals 객체로 지정된 컨텍스트에서 str에서 파이썬 소스 코드를 실행합니다. globals는 딕셔너리이어야 합니다. locals는 매핑 프로토콜을 구현하는 모든 객체가 될 수 있습니다. 매개 변수 start는 소스 코드를 구문 분석하는 데 사용해야 하는 시작 토큰을 지정합니다.

코드를 실행한 결과를 파이썬 객체로 반환하거나, 예외가 발생하면 NULL을 반환합니다.

PyObject *PyRun_File(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals)

Return value: New reference.

아래 PyRun_FileExFlags()의 단순화된 인터페이스입니다. closeit을 0으로, flags를 NULL로 설정된 상태로 남겨둡니다.

PyObject *PyRun_FileEx(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, int closeit)

Return value: New reference.

아래 PyRun_FileExFlags()의 단순화된 인터페이스입니다. flags를 NULL로 설정된 상태로 남겨둡니다.

PyObject *PyRun_FileFlags(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, PyCompilerFlags *flags)

Return value: New reference.

아래 PyRun_FileExFlags()의 단순화된 인터페이스입니다. closeit을 0으로 설정된 상태로 남겨둡니다.

PyObject *PyRun_FileExFlags(FILE *fp, const char *filename, int start, PyObject *globals, PyObject *locals, int closeit, PyCompilerFlags *flags)

Return value: New reference.

Similar to PyRun_StringFlags(), but the Python source code is read from fp instead of an in-memory string. filename should be the name of the file, it is decoded from the filesystem encoding and error handler. If closeit is true, the file is closed before PyRun_FileExFlags() returns.

PyObject *Py_CompileString(const char *str, const char *filename, int start)

Return value: New reference. Part of the Stable ABI.

아래 Py_CompileStringFlags() 의 단순화된 인터페이스입니다. flags를 NULL로 설정된 상태로 유지합니다.

PyObject *Py_CompileStringFlags(const char *str, const char *filename, int start, PyCompilerFlags *flags)

Return value: New reference.

아래 Py_CompileStringExFlags() 의 단순화된 인터페이스입니다. optimize를 -1로 설정된 상태로 유지합니다.

PyObject *Py_CompileStringObject(const char *str, PyObject *filename, int start, PyCompilerFlags *flags, int optimize)

Return value: New reference.

Parse and compile the Python source code in str, returning the resulting code object. The start token is given by start; this can be used to constrain the code which can be compiled and should be Py_eval_input, Py_file_input, or Py_single_input. The filename specified by filename is used to construct the code object and may appear in tracebacks or SyntaxError exception messages. This returns NULL if the code cannot be parsed or compiled.

정수 optimize는 컴파일러의 최적화 수준을 지정합니다. -1 값은 -O 옵션으로 주어진 것처럼 인터프리터의 최적화 수준을 선택합니다. 명시적 수준은 0 (최적화 없음; __debug__가 참), 1 (어서션이 제거되고 __debug__가 거짓) 또는 2 (독스트링도 제거됩니다)입니다.

Added in version 3.4.

PyObject *Py_CompileStringExFlags(const char *str, const char *filename, int start, PyCompilerFlags *flags, int optimize)

Return value: New reference.

Like Py_CompileStringObject(), but filename is a byte string decoded from the filesystem encoding and error handler.

Added in version 3.2.

PyObject *PyEval_EvalCode(PyObject *co, PyObject *globals, PyObject *locals)

Return value: New reference. Part of the Stable ABI.

이것은 코드 객체와 전역 변수 및 지역 변수만 있는, PyEval_EvalCodeEx()의 단순화된 인터페이스입니다. 다른 인자는 NULL로 설정됩니다.

PyObject *PyEval_EvalCodeEx(PyObject *co, PyObject *globals, PyObject *locals, PyObject *const *args, int argcount, PyObject *const *kws, int kwcount, PyObject *const *defs, int defcount, PyObject *kwdefs, PyObject *closure)

Return value: New reference. Part of the Stable ABI.

주어진 평가를 위한 특정 환경에서, 미리 컴파일된 코드 객체를 평가합니다. 이 환경은 전역 변수의 딕셔너리, 지역 변수의 매핑 객체, 인자의 배열, 키워드와 기본값, 키워드 전용 인자의 기본값 딕셔너리 및 셀의 클로저 튜플로 구성됩니다.

PyObject *PyEval_EvalFrame(PyFrameObject *f)

Return value: New reference. Part of the Stable ABI.

실행 프레임을 평가합니다. 이전 버전과의 호환성을 위한, PyEval_EvalFrameEx()의 단순화된 인터페이스입니다.

PyObject *PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)

Return value: New reference. Part of the Stable ABI.

이것은 파이썬 인터프리트의 메인, 꾸미지 않은 함수입니다. 실행 프레임 f와 연관된 코드 객체가 실행됩니다. 필요에 따라 바이트 코드를 해석하고 호출을 실행합니다. 추가 throwflag 매개 변수는 대체로 무시할 수 있습니다 - 참이면, 예외가 즉시 발생하도록 합니다; 제너레이터 객체의 throw() 메서드에 사용됩니다.

버전 3.4에서 변경: 이 함수는 이제 활성 예외를 조용히 버리지 않았는지 확인하도록 도우려고 디버그 어서션을 포함합니다.

int PyEval_MergeCompilerFlags(PyCompilerFlags *cf)

이 함수는 현재 평가 프레임의 플래그를 변경하고, 성공하면 참을, 실패하면 거짓을 반환합니다.

int Py_eval_input

격리된 표현식을 위한 파이썬 문법의 시작 기호; Py_CompileString()과 함께 사용합니다.

int Py_file_input

파일이나 다른 소스에서 읽은 문장의 시퀀스를 위한 파이썬 문법의 시작 기호; Py_CompileString()과 함께 사용합니다. 임의로 긴 파이썬 소스 코드를 컴파일할 때 사용하는 기호입니다.

int Py_single_input

단일 문장을 위한 파이썬 문법의 시작 기호; Py_CompileString()과 함께 사용합니다. 대화식 인터프리터 루프에 사용되는 기호입니다.

struct PyCompilerFlags

이것은 컴파일러 플래그를 담는 데 사용되는 구조체입니다. 코드가 컴파일되기만 하는 경우 int flags로 전달되고, 코드가 실행되는 경우 PyCompilerFlags *flags로 전달됩니다. 이 경우, from __future__ import는 flags를 수정할 수 있습니다.

Whenever PyCompilerFlags *flags is NULL, cf_flags is treated as equal to 0, and any modification due to from __future__ import is discarded.

int cf_flags

컴파일러 플래그.

int cf_feature_version

cf_feature_version은 부 파이썬 버전입니다. PY_MINOR_VERSION으로 초기화되어야 합니다.

The field is ignored by default, it is used if and only if PyCF_ONLY_AST flag is set in cf_flags.

버전 3.8에서 변경: cf_feature_version 필드를 추가했습니다.

int CO_FUTURE_DIVISION

flags에서 이 비트를 설정하면 PEP 238 [https://peps.python.org/pep-0238/]에 따라 나누기 연산자 /를 “실수 나누기(true division)”로 해석되도록 합니다.

참조 횟수

The functions and macros in this section are used for managing reference counts of Python objects.

Py_ssize_t Py_REFCNT(PyObject *o)

Part of the Stable ABI since version 3.14.

Get the reference count of the Python object o.

Note that the returned value may not actually reflect how many references to the object are actually held. For example, some objects are immortal and have a very high refcount that does not reflect the actual number of references. Consequently, do not rely on the returned value to be accurate, other than a value of 0 or 1.

Use the Py_SET_REFCNT() function to set an object reference count.

버전 3.10에서 변경: Py_REFCNT() is changed to the inline static function.

버전 3.11에서 변경: The parameter type is no longer const PyObject*.

void Py_SET_REFCNT(PyObject *o, Py_ssize_t refcnt)

Set the object o reference counter to refcnt.

On Python build with Free Threading, if refcnt is larger than UINT32_MAX, the object is made immortal.

This function has no effect on immortal objects.

Added in version 3.9.

버전 3.12에서 변경: Immortal objects are not modified.

void Py_INCREF(PyObject *o)

Indicate taking a new strong reference to object o, indicating it is in use and should not be destroyed.

This function has no effect on immortal objects.

This function is usually used to convert a borrowed reference to a strong reference in-place. The Py_NewRef() function can be used to create a new strong reference.

When done using the object, release is by calling Py_DECREF().

The object must not be NULL; if you aren’t sure that it isn’t NULL, use Py_XINCREF().

Do not expect this function to actually modify o in any way. For at least some objects [https://peps.python.org/pep-0683/], this function has no effect.

버전 3.12에서 변경: Immortal objects are not modified.

void Py_XINCREF(PyObject *o)

Similar to Py_INCREF(), but the object o can be NULL, in which case this has no effect.

See also Py_XNewRef().

PyObject *Py_NewRef(PyObject *o)

Part of the Stable ABI since version 3.10.

Create a new strong reference to an object: call Py_INCREF() on o and return the object o.

When the strong reference is no longer needed, Py_DECREF() should be called on it to release the reference.

The object o must not be NULL; use Py_XNewRef() if o can be NULL.

For example:

Py_INCREF(obj);
self->attr = obj;

can be written as:

self->attr = Py_NewRef(obj);

See also Py_INCREF().

Added in version 3.10.

PyObject *Py_XNewRef(PyObject *o)

Part of the Stable ABI since version 3.10.

Similar to Py_NewRef(), but the object o can be NULL.

If the object o is NULL, the function just returns NULL.

Added in version 3.10.

void Py_DECREF(PyObject *o)

Release a strong reference to object o, indicating the reference is no longer used.

This function has no effect on immortal objects.

Once the last strong reference is released (i.e. the object’s reference count reaches 0), the object’s type’s deallocation function (which must not be NULL) is invoked.

This function is usually used to delete a strong reference before exiting its scope.

The object must not be NULL; if you aren’t sure that it isn’t NULL, use Py_XDECREF().

Do not expect this function to actually modify o in any way. For at least some objects [https://peps.python.org/pep-0683/], this function has no effect.

경고

The deallocation function can cause arbitrary Python code to be invoked (e.g. when a class instance with a __del__() method is deallocated). While exceptions in such code are not propagated, the executed code has free access to all Python global variables. This means that any object that is reachable from a global variable should be in a consistent state before Py_DECREF() is invoked. For example, code to delete an object from a list should copy a reference to the deleted object in a temporary variable, update the list data structure, and then call Py_DECREF() for the temporary variable.

버전 3.12에서 변경: Immortal objects are not modified.

void Py_XDECREF(PyObject *o)

Similar to Py_DECREF(), but the object o can be NULL, in which case this has no effect. The same warning from Py_DECREF() applies here as well.

void Py_CLEAR(PyObject *o)

Release a strong reference for object o. The object may be NULL, in which case the macro has no effect; otherwise the effect is the same as for Py_DECREF(), except that the argument is also set to NULL. The warning for Py_DECREF() does not apply with respect to the object passed because the macro carefully uses a temporary variable and sets the argument to NULL before releasing the reference.

It is a good idea to use this macro whenever releasing a reference to an object that might be traversed during garbage collection.

버전 3.12에서 변경: The macro argument is now only evaluated once. If the argument has side effects, these are no longer duplicated.

void Py_IncRef(PyObject *o)

Part of the Stable ABI.

Indicate taking a new strong reference to object o. A function version of Py_XINCREF(). It can be used for runtime dynamic embedding of Python.

void Py_DecRef(PyObject *o)

Part of the Stable ABI.

Release a strong reference to object o. A function version of Py_XDECREF(). It can be used for runtime dynamic embedding of Python.

Py_SETREF(dst, src)

Macro safely releasing a strong reference to object dst and setting dst to src.

As in case of Py_CLEAR(), “the obvious” code can be deadly:

Py_DECREF(dst);
dst = src;

The safe way is:

Py_SETREF(dst, src);

That arranges to set dst to src _before_ releasing the reference to the old value of dst, so that any code triggered as a side-effect of dst getting torn down no longer believes dst points to a valid object.

Added in version 3.6.

버전 3.12에서 변경: The macro arguments are now only evaluated once. If an argument has side effects, these are no longer duplicated.

Py_XSETREF(dst, src)

Variant of Py_SETREF macro that uses Py_XDECREF() instead of Py_DECREF().

Added in version 3.6.

버전 3.12에서 변경: The macro arguments are now only evaluated once. If an argument has side effects, these are no longer duplicated.

예외 처리

The functions described in this chapter will let you handle and raise Python exceptions. It is important to understand some of the basics of Python exception handling. It works somewhat like the POSIX errno variable: there is a global indicator (per thread) of the last error that occurred. Most C API functions don’t clear this on success, but will set it to indicate the cause of the error on failure. Most C API functions also return an error indicator, usually NULL if they are supposed to return a pointer, or -1 if they return an integer (exception: the PyArg_* functions return 1 for success and 0 for failure).

구체적으로, 에러 표시기는 세 가지 객체 포인터로 구성됩니다: 예외 형, 예외 값 및 트레이스백 객체. 이러한 포인터들은 설정되지 않으면 NULL이 될 수 있습니다 (하지만 일부 조합은 금지되어 있습니다, 예를 들어 예외 형이 NULL이면 NULL이 아닌 트레이스백을 가질 수 없습니다).

호출한 일부 함수가 실패하여 함수가 실패해야 할 때, 일반적으로 에러 표시기를 설정하지 않습니다; 호출된 함수가 이미 설정했습니다. 에러를 처리하고 예외를 지우거나 보유한 모든 리소스(가령 객체 참조나 메모리 할당)를 정리한 후 반환해야 할 책임이 있습니다; 에러를 처리할 준비가 되지 않았을 때 정상적으로 계속되지 않아야 합니다. 에러로 인해 반환하면, 호출자에게 에러가 설정되었음을 알리는 것이 중요합니다. 에러를 처리하지 않거나 신중하게 전파하지 않으면, 파이썬/C API에 대한 추가 호출이 의도한 대로 작동하지 않을 수 있으며 알 수 없는 방식으로 실패할 수 있습니다.

참고

The error indicator is not the result of sys.exc_info(). The former corresponds to an exception that is not yet caught (and is therefore still propagating), while the latter returns an exception after it is caught (and has therefore stopped propagating).

인쇄와 지우기

void PyErr_Clear()

Part of the Stable ABI.

에러 표시기를 지웁니다. 에러 표시기가 설정되어 있지 않으면 효과가 없습니다.

void PyErr_PrintEx(int set_sys_last_vars)

Part of the Stable ABI.

표준 트레이스백을 sys.stderr로 인쇄하고 에러 표시기를 지웁니다. 에러가 SystemExit가 아닌 한, 이 경우에는 트레이스백이 인쇄되지 않고 파이썬 프로세스는 SystemExit 인스턴스에 의해 지정된 에러 코드로 종료됩니다.

에러 표시기가 설정된 경우**에만** 이 함수를 호출하십시오. 그렇지 않으면 치명적인 에러가 발생합니다!

If set_sys_last_vars is nonzero, the variable sys.last_exc is set to the printed exception. For backwards compatibility, the deprecated variables sys.last_type, sys.last_value and sys.last_traceback are also set to the type, value and traceback of this exception, respectively.

버전 3.12에서 변경: The setting of sys.last_exc was added.

void PyErr_Print()

Part of the Stable ABI.

PyErr_PrintEx(1)의 별칭.

void PyErr_WriteUnraisable(PyObject *obj)

Part of the Stable ABI.

현재 예외와 obj 인자를 사용하여 sys.unraisablehook() 을 호출합니다.

This utility function prints a warning message to sys.stderr when an exception has been set but it is impossible for the interpreter to actually raise the exception. It is used, for example, when an exception occurs in an __del__() method.

The function is called with a single argument obj that identifies the context in which the unraisable exception occurred. If possible, the repr of obj will be printed in the warning message. If obj is NULL, only the traceback is printed.

이 함수를 호출할 때 예외를 설정되어 있어야 합니다.

버전 3.4에서 변경: Print a traceback. Print only traceback if obj is NULL.

버전 3.8에서 변경: Use sys.unraisablehook().

void PyErr_FormatUnraisable(const char *format, ...)

Similar to PyErr_WriteUnraisable(), but the format and subsequent parameters help format the warning message; they have the same meaning and values as in PyUnicode_FromFormat(). PyErr_WriteUnraisable(obj) is roughly equivalent to PyErr_FormatUnraisable("Exception ignored in: %R", obj). If format is NULL, only the traceback is printed.

Added in version 3.13.

void PyErr_DisplayException(PyObject *exc)

Part of the Stable ABI since version 3.12.

Print the standard traceback display of exc to sys.stderr, including chained exceptions and notes.

Added in version 3.12.

예외 발생시키기

이 함수들은 현재 스레드의 에러 표시기를 설정하는 데 도움이 됩니다. 편의를 위해, 이러한 함수 중 일부는 항상 return 문에서 사용할 NULL 포인터를 반환합니다.

void PyErr_SetString(PyObject *type, const char *message)

Part of the Stable ABI.

This is the most common way to set the error indicator. The first argument specifies the exception type; it is normally one of the standard exceptions, e.g. PyExc_RuntimeError. You need not create a new strong reference to it (e.g. with Py_INCREF()). The second argument is an error message; it is decoded from 'utf-8'.

void PyErr_SetObject(PyObject *type, PyObject *value)

Part of the Stable ABI.

이 함수는 PyErr_SetString()과 유사하지만, 예외의 “값”에 대해 임의의 파이썬 객체를 지정할 수 있습니다.

PyObject *PyErr_Format(PyObject *exception, const char *format, ...)

Return value: Always NULL. Part of the Stable ABI.

이 함수는 에러 표시기를 설정하고 NULL을 반환합니다. exception은 파이썬 예외 클래스여야 합니다. format과 후속 매개 변수는 에러 메시지를 포맷하는 데 도움이 됩니다; PyUnicode_FromFormat()에서와 같은 의미와 값을 갖습니다. format은 ASCII 인코딩된 문자열입니다.

PyObject *PyErr_FormatV(PyObject *exception, const char *format, va_list vargs)

Return value: Always NULL. Part of the Stable ABI since version 3.5.

PyErr_Format()과 같지만, 가변 개수의 인자 대신 va_list 인자를 취합니다.

Added in version 3.5.

void PyErr_SetNone(PyObject *type)

Part of the Stable ABI.

이것은 PyErr_SetObject(type, Py_None)의 줄임 표현입니다.

int PyErr_BadArgument()

Part of the Stable ABI.

이것은 PyErr_SetString(PyExc_TypeError, message)의 줄임 표현입니다, 여기서 message는 잘못된 인자로 내장 연산이 호출되었음을 나타냅니다. 대부분 내부 용입니다.

PyObject *PyErr_NoMemory()

Return value: Always NULL. Part of the Stable ABI.

이것은 PyErr_SetNone(PyExc_MemoryError)의 줄임 표현입니다; NULL을 반환해서 객체 할당 함수는 메모리가 부족할 때 return PyErr_NoMemory(); 라고 쓸 수 있습니다.

PyObject *PyErr_SetFromErrno(PyObject *type)

Return value: Always NULL. Part of the Stable ABI.

This is a convenience function to raise an exception when a C library function has returned an error and set the C variable errno. It constructs a tuple object whose first item is the integer errno value and whose second item is the corresponding error message (gotten from strerror()), and then calls PyErr_SetObject(type, object). On Unix, when the errno value is EINTR, indicating an interrupted system call, this calls PyErr_CheckSignals(), and if that set the error indicator, leaves it set to that. The function always returns NULL, so a wrapper function around a system call can write return PyErr_SetFromErrno(type); when the system call returns an error.

PyObject *PyErr_SetFromErrnoWithFilenameObject(PyObject *type, PyObject *filenameObject)

Return value: Always NULL. Part of the Stable ABI.

Similar to PyErr_SetFromErrno(), with the additional behavior that if filenameObject is not NULL, it is passed to the constructor of type as a third parameter. In the case of OSError exception, this is used to define the filename attribute of the exception instance.

PyObject *PyErr_SetFromErrnoWithFilenameObjects(PyObject *type, PyObject *filenameObject, PyObject *filenameObject2)

Return value: Always NULL. Part of the Stable ABI since version 3.7.

PyErr_SetFromErrnoWithFilenameObject()와 유사하지만, 두 개의 파일명을 취하는 함수가 실패할 때 에러를 발생시키기 위해 두 번째 파일명 객체를 취합니다.

Added in version 3.4.

PyObject *PyErr_SetFromErrnoWithFilename(PyObject *type, const char *filename)

Return value: Always NULL. Part of the Stable ABI.

Similar to PyErr_SetFromErrnoWithFilenameObject(), but the filename is given as a C string. filename is decoded from the filesystem encoding and error handler.

PyObject *PyErr_SetFromWindowsErr(int ierr)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

This is a convenience function to raise OSError. If called with ierr of 0, the error code returned by a call to GetLastError() is used instead. It calls the Win32 function FormatMessage() to retrieve the Windows description of error code given by ierr or GetLastError(), then it constructs a OSError object with the winerror attribute set to the error code, the strerror attribute set to the corresponding error message (gotten from FormatMessage()), and then calls PyErr_SetObject(PyExc_OSError, object). This function always returns NULL.

Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErr(PyObject *type, int ierr)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

PyErr_SetFromWindowsErr() 와 유사하며, 발생시킬 예외 형을 지정하는 추가 매개 변수가 있습니다.

Availability: Windows.

PyObject *PyErr_SetFromWindowsErrWithFilename(int ierr, const char *filename)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

Similar to PyErr_SetFromWindowsErr(), with the additional behavior that if filename is not NULL, it is decoded from the filesystem encoding (os.fsdecode()) and passed to the constructor of OSError as a third parameter to be used to define the filename attribute of the exception instance.

Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(PyObject *type, int ierr, PyObject *filename)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

Similar to PyErr_SetExcFromWindowsErr(), with the additional behavior that if filename is not NULL, it is passed to the constructor of OSError as a third parameter to be used to define the filename attribute of the exception instance.

Availability: Windows.

PyObject *PyErr_SetExcFromWindowsErrWithFilenameObjects(PyObject *type, int ierr, PyObject *filename, PyObject *filename2)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

PyErr_SetExcFromWindowsErrWithFilenameObject()와 유사하지만, 두 번째 파일명 객체를 받아들입니다.

Availability: Windows.

Added in version 3.4.

PyObject *PyErr_SetExcFromWindowsErrWithFilename(PyObject *type, int ierr, const char *filename)

Return value: Always NULL. Part of the Stable ABI on Windows since version 3.7.

PyErr_SetFromWindowsErrWithFilename()와 유사하며, 발생시킬 예외 형을 지정하는 추가 매개 변수가 있습니다.

Availability: Windows.

PyObject *PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)

Return value: Always NULL. Part of the Stable ABI since version 3.7.

ImportError를 발생시키는 편의 함수입니다. msg는 예외의 메시지 문자열로 설정됩니다. 둘 다 NULL이 될 수 있는, name과 path는 각각 ImportError의 name과 path 어트리뷰트로 설정됩니다.

Added in version 3.3.

PyObject *PyErr_SetImportErrorSubclass(PyObject *exception, PyObject *msg, PyObject *name, PyObject *path)

Return value: Always NULL. Part of the Stable ABI since version 3.6.

PyErr_SetImportError() 와 매우 비슷하지만, 이 함수는 발생시킬 ImportError의 서브 클래스를 지정할 수 있습니다.

Added in version 3.6.

void PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)

현재 예외에 대한 파일(file), 줄(line) 및 오프셋(offset) 정보를 설정합니다. 현재 예외가 SyntaxError가 아니면, 추가 어트리뷰트를 설정하여, 예외 인쇄 하위 시스템이 예외가 SyntaxError라고 생각하게 합니다.

Added in version 3.4.

void PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)

Part of the Stable ABI since version 3.7.

Like PyErr_SyntaxLocationObject(), but filename is a byte string decoded from the filesystem encoding and error handler.

Added in version 3.2.

void PyErr_SyntaxLocation(const char *filename, int lineno)

Part of the Stable ABI.

Like PyErr_SyntaxLocationEx(), but the col_offset parameter is omitted.

void PyErr_BadInternalCall()

Part of the Stable ABI.

이것은 PyErr_SetString(PyExc_SystemError, message)의 줄임 표현입니다. 여기서 message는 내부 연산(예를 들어 파이썬/C API 함수)이 잘못된 인자로 호출되었음을 나타냅니다. 대부분 내부 용입니다.

경고 발행하기

이 함수를 사용하여 C 코드에서 경고를 발행하십시오. 파이썬 warnings 모듈에서 내보낸 유사한 함수를 미러링합니다. 일반적으로 sys.stderr에 경고 메시지를 인쇄합니다; 그러나, 사용자가 경고를 에러로 전환하도록 지정했을 수도 있으며, 이 경우 예외가 발생합니다. 경고 장치의 문제로 인해 이 함수가 예외를 발생시키는 것도 가능합니다. 예외가 발생하지 않으면 반환 값은 0이고, 예외가 발생하면 -1입니다. (경고 메시지가 실제로 인쇄되는지나 예외의 이유를 확인할 수 없습니다; 이것은 의도적입니다.) 예외가 발생하면, 호출자는 정상적인 예외 처리를 수행해야 합니다 (예를 들어, 소유한 참조를 Py_DECREF()하고 에러값을 반환합니다).

int PyErr_WarnEx(PyObject *category, const char *message, Py_ssize_t stack_level)

Part of the Stable ABI.

경고 메시지를 발행합니다. category 인자는 경고 범주(아래를 참조하십시오)나 NULL입니다; message 인자는 UTF-8로 인코딩된 문자열입니다. stack_level은 스택 프레임 수를 제공하는 양수입니다; 해당 스택 프레임에서 현재 실행 중인 코드 줄에서 경고가 발생합니다. stack_level이 1이면 PyErr_WarnEx()를 호출하는 함수, 2는 그 위의 함수, 등등.

경고 범주는 PyExc_Warning의 서브 클래스여야 합니다. PyExc_Warning은 PyExc_Exception의 서브 클래스입니다; 기본 경고 범주는 PyExc_RuntimeWarning입니다. 표준 파이썬 경고 범주는 이름이 표준 경고 범주 에 열거된 전역 변수로 제공됩니다.

경고 제어에 대한 자세한 내용은, warnings 모듈 설명서와 명령 줄 설명서에서 -W 옵션을 참조하십시오. 경고 제어를 위한 C API는 없습니다.

int PyErr_WarnExplicitObject(PyObject *category, PyObject *message, PyObject *filename, int lineno, PyObject *module, PyObject *registry)

Issue a warning message with explicit control over all warning attributes. This is a straightforward wrapper around the Python function warnings.warn_explicit(); see there for more information. The module and registry arguments may be set to NULL to get the default effect described there.

Added in version 3.4.

int PyErr_WarnExplicit(PyObject *category, const char *message, const char *filename, int lineno, const char *module, PyObject *registry)

Part of the Stable ABI.

Similar to PyErr_WarnExplicitObject() except that message and module are UTF-8 encoded strings, and filename is decoded from the filesystem encoding and error handler.

int PyErr_WarnFormat(PyObject *category, Py_ssize_t stack_level, const char *format, ...)

Part of the Stable ABI.

PyErr_WarnEx()와 유사한 함수지만, PyUnicode_FromFormat()을 사용하여 경고 메시지를 포맷합니다. format은 ASCII 인코딩된 문자열입니다.

Added in version 3.2.

int PyErr_ResourceWarning(PyObject *source, Py_ssize_t stack_level, const char *format, ...)

Part of the Stable ABI since version 3.6.

Function similar to PyErr_WarnFormat(), but category is ResourceWarning and it passes source to warnings.WarningMessage.

Added in version 3.6.

에러 표시기 조회하기

PyObject *PyErr_Occurred()

Return value: Borrowed reference. Part of the Stable ABI.

Test whether the error indicator is set. If set, return the exception type (the first argument to the last call to one of the PyErr_Set* functions or to PyErr_Restore()). If not set, return NULL. You do not own a reference to the return value, so you do not need to Py_DECREF() it.

호출자는 GIL을 보유해야 합니다.

참고

반환 값을 특정 예외와 비교하지 마십시오; 대신 PyErr_ExceptionMatches()를 사용하십시오, 아래를 참조하십시오. (클래스 예외의 경우 예외가 클래스 대신 인스턴스이거나, 예상하는 예외의 서브 클래스일 수 있어서 비교는 실패하기 쉽습니다.)

int PyErr_ExceptionMatches(PyObject *exc)

Part of the Stable ABI.

PyErr_GivenExceptionMatches(PyErr_Occurred(), exc)와 동등합니다. 예외가 실제로 설정되었을 때만 호출해야 합니다; 예외가 발생하지 않았으면 메모리 액세스 위반이 발생합니다.

int PyErr_GivenExceptionMatches(PyObject *given, PyObject *exc)

Part of the Stable ABI.

given 예외가 exc의 예외 형과 일치하면 참을 반환합니다. exc가 클래스 객체이면, given이 서브 클래스의 인스턴스일 때도 참을 반환합니다. exc가 튜플이면, 튜플에 있는 모든 예외 형(그리고 서브 튜플도 재귀적으로)을 일치를 위해 검색합니다.

PyObject *PyErr_GetRaisedException(void)

Return value: New reference. Part of the Stable ABI since version 3.12.

Return the exception currently being raised, clearing the error indicator at the same time. Return NULL if the error indicator is not set.

This function is used by code that needs to catch exceptions, or code that needs to save and restore the error indicator temporarily.

For example:

{
   PyObject *exc = PyErr_GetRaisedException();

   /* ... code that might produce other errors ... */

   PyErr_SetRaisedException(exc);
}

더 보기

PyErr_GetHandledException(), to save the exception currently being handled.

Added in version 3.12.

void PyErr_SetRaisedException(PyObject *exc)

Part of the Stable ABI since version 3.12.

Set exc as the exception currently being raised, clearing the existing exception if one is set.

경고

This call steals a reference to exc, which must be a valid exception.

Added in version 3.12.

void PyErr_Fetch(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)

Part of the Stable ABI.

버전 3.12부터 폐지됨: Use PyErr_GetRaisedException() instead.

주소가 전달된 세 개의 변수로 에러 표시기를 꺼냅니다. 에러 표시기가 설정되지 않았으면, 세 변수를 모두 NULL로 설정합니다. 설정되었으면, 지워지고 꺼낸 각 객체에 대한 참조를 여러분이 소유합니다. 값과 트레이스백 객체는 형 객체가 그렇지 않을 때도 NULL일 수 있습니다.

참고

This function is normally only used by legacy code that needs to catch exceptions or save and restore the error indicator temporarily.

For example:

{
   PyObject *type, *value, *traceback;
   PyErr_Fetch(&type, &value, &traceback);

   /* ... code that might produce other errors ... */

   PyErr_Restore(type, value, traceback);
}

void PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback)

Part of the Stable ABI.

버전 3.12부터 폐지됨: Use PyErr_SetRaisedException() instead.

Set the error indicator from the three objects, type, value, and traceback, clearing the existing exception if one is set. If the objects are NULL, the error indicator is cleared. Do not pass a NULL type and non-NULL value or traceback. The exception type should be a class. Do not pass an invalid exception type or value. (Violating these rules will cause subtle problems later.) This call takes away a reference to each object: you must own a reference to each object before the call and after the call you no longer own these references. (If you don’t understand this, don’t use this function. I warned you.)

참고

This function is normally only used by legacy code that needs to save and restore the error indicator temporarily. Use PyErr_Fetch() to save the current error indicator.

void PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb)

Part of the Stable ABI.

버전 3.12부터 폐지됨: Use PyErr_GetRaisedException() instead, to avoid any possible de-normalization.

특정 상황에서, 아래의 PyErr_Fetch()가 반환하는 값은 “비 정규화”되었을 수 있습니다. 즉, *exc는 클래스 객체이지만 *val은 같은 클래스의 인스턴스가 아닙니다. 이 함수는 이 경우 클래스를 인스턴스 화하는 데 사용할 수 있습니다. 값이 이미 정규화되어 있으면, 아무 일도 일어나지 않습니다. 지연된 정규화는 성능 향상을 위해 구현됩니다.

참고

This function does not implicitly set the __traceback__ attribute on the exception value. If setting the traceback appropriately is desired, the following additional snippet is needed:

if (tb != NULL) {
  PyException_SetTraceback(val, tb);
}

PyObject *PyErr_GetHandledException(void)

Part of the Stable ABI since version 3.11.

Retrieve the active exception instance, as would be returned by sys.exception(). This refers to an exception that was already caught, not to an exception that was freshly raised. Returns a new reference to the exception or NULL. Does not modify the interpreter’s exception state.

참고

This function is not normally used by code that wants to handle exceptions. Rather, it can be used when code needs to save and restore the exception state temporarily. Use PyErr_SetHandledException() to restore or clear the exception state.

Added in version 3.11.

void PyErr_SetHandledException(PyObject *exc)

Part of the Stable ABI since version 3.11.

Set the active exception, as known from sys.exception(). This refers to an exception that was already caught, not to an exception that was freshly raised. To clear the exception state, pass NULL.

참고

This function is not normally used by code that wants to handle exceptions. Rather, it can be used when code needs to save and restore the exception state temporarily. Use PyErr_GetHandledException() to get the exception state.

Added in version 3.11.

void PyErr_GetExcInfo(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback)

Part of the Stable ABI since version 3.7.

Retrieve the old-style representation of the exception info, as known from sys.exc_info(). This refers to an exception that was already caught, not to an exception that was freshly raised. Returns new references for the three objects, any of which may be NULL. Does not modify the exception info state. This function is kept for backwards compatibility. Prefer using PyErr_GetHandledException().

참고

이 함수는 일반적으로 예외를 처리하려는 코드에서 사용되지 않습니다. 오히려, 코드가 예외 상태를 임시로 저장하고 복원해야 할 때 사용할 수 있습니다. 예외 상태를 복원하거나 지우려면 PyErr_SetExcInfo()를 사용하십시오.

Added in version 3.3.

void PyErr_SetExcInfo(PyObject *type, PyObject *value, PyObject *traceback)

Part of the Stable ABI since version 3.7.

Set the exception info, as known from sys.exc_info(). This refers to an exception that was already caught, not to an exception that was freshly raised. This function steals the references of the arguments. To clear the exception state, pass NULL for all three arguments. This function is kept for backwards compatibility. Prefer using PyErr_SetHandledException().

참고

이 함수는 일반적으로 예외를 처리하려는 코드에서 사용되지 않습니다. 오히려, 코드가 예외 상태를 임시로 저장하고 복원해야 할 때 사용할 수 있습니다. 예외 상태를 읽으려면 PyErr_GetExcInfo()를 사용하십시오.

Added in version 3.3.

버전 3.11에서 변경: The type and traceback arguments are no longer used and can be NULL. The interpreter now derives them from the exception instance (the value argument). The function still steals references of all three arguments.

시그널 처리하기

int PyErr_CheckSignals()

Part of the Stable ABI.

This function interacts with Python’s signal handling.

If the function is called from the main thread and under the main Python interpreter, it checks whether a signal has been sent to the processes and if so, invokes the corresponding signal handler. If the signal module is supported, this can invoke a signal handler written in Python.

The function attempts to handle all pending signals, and then returns 0. However, if a Python signal handler raises an exception, the error indicator is set and the function returns -1 immediately (such that other pending signals may not have been handled yet: they will be on the next PyErr_CheckSignals() invocation).

If the function is called from a non-main thread, or under a non-main Python interpreter, it does nothing and returns 0.

This function can be called by long-running C code that wants to be interruptible by user requests (such as by pressing Ctrl-C).

참고

The default Python signal handler for SIGINT raises the KeyboardInterrupt exception.

void PyErr_SetInterrupt()

Part of the Stable ABI.

Simulate the effect of a SIGINT signal arriving. This is equivalent to PyErr_SetInterruptEx(SIGINT).

참고

This function is async-signal-safe. It can be called without the GIL and from a C signal handler.

int PyErr_SetInterruptEx(int signum)

Part of the Stable ABI since version 3.10.

Simulate the effect of a signal arriving. The next time PyErr_CheckSignals() is called, the Python signal handler for the given signal number will be called.

This function can be called by C code that sets up its own signal handling and wants Python signal handlers to be invoked as expected when an interruption is requested (for example when the user presses Ctrl-C to interrupt an operation).

If the given signal isn’t handled by Python (it was set to signal.SIG_DFL or signal.SIG_IGN), it will be ignored.

If signum is outside of the allowed range of signal numbers, -1 is returned. Otherwise, 0 is returned. The error indicator is never changed by this function.

참고

This function is async-signal-safe. It can be called without the GIL and from a C signal handler.

Added in version 3.10.

int PySignal_SetWakeupFd(int fd)

이 유틸리티 함수는 시그널이 수신될 때마다 시그널 번호가 단일 바이트로 기록되는 파일 기술자를 지정합니다. fd는 비 블로킹이어야 합니다. 이전의 파일 기술자를 반환합니다.

값 -1은 기능을 비활성화합니다; 이것이 초기 상태입니다. 이것은 파이썬의 signal.set_wakeup_fd()와 동등하지만, 에러 검사는 없습니다. fd는 유효한 파일 기술자여야 합니다. 함수는 메인 스레드에서만 호출되어야 합니다.

버전 3.5에서 변경: 윈도우에서, 함수는 이제 소켓 핸들도 지원합니다.

예외 클래스

PyObject *PyErr_NewException(const char *name, PyObject *base, PyObject *dict)

Return value: New reference. Part of the Stable ABI.

이 유틸리티 함수는 새 예외 클래스를 만들고 반환합니다. name 인자는 새 예외의 이름, module.classname 형식의 C 문자열이어야 합니다. base와 dict 인자는 일반적으로 NULL입니다. 이렇게 하면 Exception(C에서 PyExc_Exception으로 액세스할 수 있습니다)에서 파생된 클래스 객체가 만들어집니다.

The __module__ attribute of the new class is set to the first part (up to the last dot) of the name argument, and the class name is set to the last part (after the last dot). The base argument can be used to specify alternate base classes; it can either be only one class or a tuple of classes. The dict argument can be used to specify a dictionary of class variables and methods.

PyObject *PyErr_NewExceptionWithDoc(const char *name, const char *doc, PyObject *base, PyObject *dict)

Return value: New reference. Part of the Stable ABI.

새로운 예외 클래스에 독스트링을 쉽게 부여할 수 있다는 점을 제외하면 PyErr_NewException()과 같습니다: doc이 NULL이 아니면, 예외 클래스에 대한 독스트링으로 사용됩니다.

Added in version 3.2.

예외 객체

PyObject *PyException_GetTraceback(PyObject *ex)

Return value: New reference. Part of the Stable ABI.

Return the traceback associated with the exception as a new reference, as accessible from Python through the __traceback__ attribute. If there is no traceback associated, this returns NULL.

int PyException_SetTraceback(PyObject *ex, PyObject *tb)

Part of the Stable ABI.

예외와 관련된 트레이스백을 tb로 설정합니다. 지우려면 Py_None을 사용하십시오.

PyObject *PyException_GetContext(PyObject *ex)

Return value: New reference. Part of the Stable ABI.

Return the context (another exception instance during whose handling ex was raised) associated with the exception as a new reference, as accessible from Python through the __context__ attribute. If there is no context associated, this returns NULL.

void PyException_SetContext(PyObject *ex, PyObject *ctx)

Part of the Stable ABI.

예외와 연관된 컨텍스트를 ctx로 설정합니다. 지우려면 NULL을 사용하십시오. ctx가 예외 인스턴스인지 확인하는 형 검사는 없습니다. 이것은 ctx에 대한 참조를 훔칩니다.

PyObject *PyException_GetCause(PyObject *ex)

Return value: New reference. Part of the Stable ABI.

Return the cause (either an exception instance, or None, set by raise ... from ...) associated with the exception as a new reference, as accessible from Python through the __cause__ attribute.

void PyException_SetCause(PyObject *ex, PyObject *cause)

Part of the Stable ABI.

Set the cause associated with the exception to cause. Use NULL to clear it. There is no type check to make sure that cause is either an exception instance or None. This steals a reference to cause.

The __suppress_context__ attribute is implicitly set to True by this function.

PyObject *PyException_GetArgs(PyObject *ex)

Return value: New reference. Part of the Stable ABI since version 3.12.

Return args of exception ex.

void PyException_SetArgs(PyObject *ex, PyObject *args)

Part of the Stable ABI since version 3.12.

Set args of exception ex to args.

PyObject *PyUnstable_Exc_PrepReraiseStar(PyObject *orig, PyObject *excs)

This is Unstable API. It may change without warning in minor releases.

Implement part of the interpreter’s implementation of except*. orig is the original exception that was caught, and excs is the list of the exceptions that need to be raised. This list contains the unhandled part of orig, if any, as well as the exceptions that were raised from the except* clauses (so they have a different traceback from orig) and those that were reraised (and have the same traceback as orig). Return the ExceptionGroup that needs to be reraised in the end, or None if there is nothing to reraise.

Added in version 3.12.

유니코드 예외 객체

다음 함수는 C에서 유니코드 예외를 만들고 수정하는 데 사용됩니다.

PyObject *PyUnicodeDecodeError_Create(const char *encoding, const char *object, Py_ssize_t length, Py_ssize_t start, Py_ssize_t end, const char *reason)

Return value: New reference. Part of the Stable ABI.

encoding, object, length, start, end 및 reason 어트리뷰트를 사용하여 UnicodeDecodeError 객체를 만듭니다. encoding과 reason은 UTF-8로 인코딩된 문자열입니다.

PyObject *PyUnicodeDecodeError_GetEncoding(PyObject *exc)

PyObject *PyUnicodeEncodeError_GetEncoding(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

주어진 예외 객체의 encoding 어트리뷰트를 반환합니다.

PyObject *PyUnicodeDecodeError_GetObject(PyObject *exc)

PyObject *PyUnicodeEncodeError_GetObject(PyObject *exc)

PyObject *PyUnicodeTranslateError_GetObject(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

주어진 예외 객체의 object 어트리뷰트를 반환합니다.

int PyUnicodeDecodeError_GetStart(PyObject *exc, Py_ssize_t *start)

int PyUnicodeEncodeError_GetStart(PyObject *exc, Py_ssize_t *start)

int PyUnicodeTranslateError_GetStart(PyObject *exc, Py_ssize_t *start)

Part of the Stable ABI.

주어진 예외 객체의 start 어트리뷰트를 가져와서 *start에 배치합니다. start는 NULL이 아니어야 합니다. 성공하면 0을, 실패하면 -1을 반환합니다.

int PyUnicodeDecodeError_SetStart(PyObject *exc, Py_ssize_t start)

int PyUnicodeEncodeError_SetStart(PyObject *exc, Py_ssize_t start)

int PyUnicodeTranslateError_SetStart(PyObject *exc, Py_ssize_t start)

Part of the Stable ABI.

주어진 예외 객체의 start 어트리뷰트를 start로 설정합니다. 성공하면 0을, 실패하면 -1을 반환합니다.

int PyUnicodeDecodeError_GetEnd(PyObject *exc, Py_ssize_t *end)

int PyUnicodeEncodeError_GetEnd(PyObject *exc, Py_ssize_t *end)

int PyUnicodeTranslateError_GetEnd(PyObject *exc, Py_ssize_t *end)

Part of the Stable ABI.

주어진 예외 객체의 end 어트리뷰트를 가져와서 *end에 배치합니다. end는 NULL이 아니어야 합니다. 성공하면 0을, 실패하면 -1을 반환합니다.

int PyUnicodeDecodeError_SetEnd(PyObject *exc, Py_ssize_t end)

int PyUnicodeEncodeError_SetEnd(PyObject *exc, Py_ssize_t end)

int PyUnicodeTranslateError_SetEnd(PyObject *exc, Py_ssize_t end)

Part of the Stable ABI.

주어진 예외 객체의 end 어트리뷰트를 end로 설정합니다. 성공하면 0을, 실패하면 -1을 반환합니다.

PyObject *PyUnicodeDecodeError_GetReason(PyObject *exc)

PyObject *PyUnicodeEncodeError_GetReason(PyObject *exc)

PyObject *PyUnicodeTranslateError_GetReason(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

주어진 예외 객체의 reason 어트리뷰트를 반환합니다.

int PyUnicodeDecodeError_SetReason(PyObject *exc, const char *reason)

int PyUnicodeEncodeError_SetReason(PyObject *exc, const char *reason)

int PyUnicodeTranslateError_SetReason(PyObject *exc, const char *reason)

Part of the Stable ABI.

주어진 예외 객체의 reason 어트리뷰트를 reason으로 설정합니다. 성공하면 0을, 실패하면 -1을 반환합니다.

재귀 제어

이 두 함수는 코어와 확장 모듈 모두에서 C 수준에서 안전한 재귀 호출을 수행하는 방법을 제공합니다. 재귀 코드가 반드시 파이썬 코드를 호출하지 않는 경우 필요합니다 (파이썬 코드는 재귀 깊이를 자동으로 추적합니다). 호출 프로토콜이 재귀 처리를 처리하기 때문에 tp_call 구현에도 필요하지 않습니다.

int Py_EnterRecursiveCall(const char *where)

Part of the Stable ABI since version 3.9.

재귀적 C 수준 호출이 막 수행되려고 하는 지점을 표시합니다.

If USE_STACKCHECK is defined, this function checks if the OS stack overflowed using PyOS_CheckStack(). If this is the case, it sets a MemoryError and returns a nonzero value.

그런 다음 함수는 재귀 제한에 도달했는지 확인합니다. 이 경우, RecursionError가 설정되고 0이 아닌 값이 반환됩니다. 그렇지 않으면, 0이 반환됩니다.

where는 재귀 깊이 제한으로 인한 RecursionError 메시지에 이어붙일 " in instance check"와 같은 UTF-8 인코딩된 문자열이어야 합니다.

버전 3.9에서 변경: This function is now also available in the limited API.

void Py_LeaveRecursiveCall(void)

Part of the Stable ABI since version 3.9.

Py_EnterRecursiveCall() 을 종료합니다. Py_EnterRecursiveCall() 의 각 성공적인 호출마다 한 번씩 호출되어야 합니다.

버전 3.9에서 변경: This function is now also available in the limited API.

컨테이너형에 대해 tp_repr을 올바르게 구현하려면 특별한 재귀 처리가 필요합니다. 스택을 보호하는 것 외에도, tp_repr은 순환을 방지하기 위해 객체를 추적해야 합니다. 다음 두 함수는 이 기능을 쉽게 만듭니다. 사실상, 이들은 reprlib.recursive_repr()에 대한 C 동등물입니다.

int Py_ReprEnter(PyObject *object)

Part of the Stable ABI.

순환을 감지하기 위해 tp_repr 구현 시작 시 호출됩니다.

객체가 이미 처리되었으면, 함수는 양의 정수를 반환합니다. 이 경우 tp_repr 구현은 순환을 나타내는 문자열 객체를 반환해야 합니다. 예를 들어, dict 객체는 {...}를 반환하고 list 객체는 [...]를 반환합니다.

재귀 제한에 도달하면 함수는 음의 정수를 반환합니다. 이 경우 tp_repr 구현은 일반적으로 NULL을 반환해야 합니다.

그렇지 않으면, 함수는 0을 반환하고 tp_repr 구현은 정상적으로 계속될 수 있습니다.

void Py_ReprLeave(PyObject *object)

Part of the Stable ABI.

Py_ReprEnter()를 종료합니다. 0을 반환하는 Py_ReprEnter() 호출마다 한 번씩 호출해야 합니다.

표준 예외

All standard Python exceptions are available as global variables whose names are PyExc_ followed by the Python exception name. These have the type PyObject*; they are all class objects. For completeness, here are all the variables:

C 이름

파이썬 이름

노트

PyExc_BaseException

BaseException

[1]

PyExc_Exception

Exception

[1]

PyExc_ArithmeticError

ArithmeticError

[1]

PyExc_AssertionError

AssertionError

PyExc_AttributeError

AttributeError

PyExc_BlockingIOError

BlockingIOError

PyExc_BrokenPipeError

BrokenPipeError

PyExc_BufferError

BufferError

PyExc_ChildProcessError

ChildProcessError

PyExc_ConnectionAbortedError

ConnectionAbortedError

PyExc_ConnectionError

ConnectionError

PyExc_ConnectionRefusedError

ConnectionRefusedError

PyExc_ConnectionResetError

ConnectionResetError

PyExc_EOFError

EOFError

PyExc_FileExistsError

FileExistsError

PyExc_FileNotFoundError

FileNotFoundError

PyExc_FloatingPointError

FloatingPointError

PyExc_GeneratorExit

GeneratorExit

PyExc_ImportError

ImportError

PyExc_IndentationError

IndentationError

PyExc_IndexError

IndexError

PyExc_InterruptedError

InterruptedError

PyExc_IsADirectoryError

IsADirectoryError

PyExc_KeyError

KeyError

PyExc_KeyboardInterrupt

KeyboardInterrupt

PyExc_LookupError

LookupError

[1]

PyExc_MemoryError

MemoryError

PyExc_ModuleNotFoundError

ModuleNotFoundError

PyExc_NameError

NameError

PyExc_NotADirectoryError

NotADirectoryError

PyExc_NotImplementedError

NotImplementedError

PyExc_OSError

OSError

[1]

PyExc_OverflowError

OverflowError

PyExc_PermissionError

PermissionError

PyExc_ProcessLookupError

ProcessLookupError

PyExc_PythonFinalizationError

PythonFinalizationError

PyExc_RecursionError

RecursionError

PyExc_ReferenceError

ReferenceError

PyExc_RuntimeError

RuntimeError

PyExc_StopAsyncIteration

StopAsyncIteration

PyExc_StopIteration

StopIteration

PyExc_SyntaxError

SyntaxError

PyExc_SystemError

SystemError

PyExc_SystemExit

SystemExit

PyExc_TabError

TabError

PyExc_TimeoutError

TimeoutError

PyExc_TypeError

TypeError

PyExc_UnboundLocalError

UnboundLocalError

PyExc_UnicodeDecodeError

UnicodeDecodeError

PyExc_UnicodeEncodeError

UnicodeEncodeError

PyExc_UnicodeError

UnicodeError

PyExc_UnicodeTranslateError

UnicodeTranslateError

PyExc_ValueError

ValueError

PyExc_ZeroDivisionError

ZeroDivisionError

Added in version 3.3: PyExc_BlockingIOError, PyExc_BrokenPipeError, PyExc_ChildProcessError, PyExc_ConnectionError, PyExc_ConnectionAbortedError, PyExc_ConnectionRefusedError, PyExc_ConnectionResetError, PyExc_FileExistsError, PyExc_FileNotFoundError, PyExc_InterruptedError, PyExc_IsADirectoryError, PyExc_NotADirectoryError, PyExc_PermissionError, PyExc_ProcessLookupError 및 PyExc_TimeoutError는 PEP 3151 [https://peps.python.org/pep-3151/]을 따라 도입되었습니다.

Added in version 3.5: PyExc_StopAsyncIteration 과 PyExc_RecursionError.

Added in version 3.6: PyExc_ModuleNotFoundError.

다음은 PyExc_OSError에 대한 호환성 별칭입니다:

C 이름

노트

PyExc_EnvironmentError

PyExc_IOError

PyExc_WindowsError

[2]

버전 3.3에서 변경: 이러한 별칭은 별도의 예외 형이었습니다.

노트:

[1] (1,2,3,4,5)

이것은 다른 표준 예외에 대한 베이스 클래스입니다.

[2]

윈도우에서만 정의됩니다; 전 처리기 매크로 MS_WINDOWS가 정의되었는지 테스트하여 이를 사용하는 코드를 보호하십시오.

표준 경고 범주

All standard Python warning categories are available as global variables whose names are PyExc_ followed by the Python exception name. These have the type PyObject*; they are all class objects. For completeness, here are all the variables:

C 이름

파이썬 이름

노트

PyExc_Warning

Warning

[3]

PyExc_BytesWarning

BytesWarning

PyExc_DeprecationWarning

DeprecationWarning

PyExc_FutureWarning

FutureWarning

PyExc_ImportWarning

ImportWarning

PyExc_PendingDeprecationWarning

PendingDeprecationWarning

PyExc_ResourceWarning

ResourceWarning

PyExc_RuntimeWarning

RuntimeWarning

PyExc_SyntaxWarning

SyntaxWarning

PyExc_UnicodeWarning

UnicodeWarning

PyExc_UserWarning

UserWarning

Added in version 3.2: PyExc_ResourceWarning.

노트:

[3]

이것은 다른 표준 경고 범주의 베이스 클래스입니다.

유틸리티

이 장의 함수들은 C 코드의 플랫폼 간 호환성 개선, C에서 파이썬 모듈 사용, 함수 인자의 구문 분석 및 C값으로부터 파이썬 값을 구성하는 것에 이르기까지 다양한 유틸리티 작업을 수행합니다.

운영 체제 유틸리티

시스템 함수

프로세스 제어

모듈 임포트 하기

데이터 마샬링 지원

인자 구문 분석과 값 구축

인자 구문 분석

문자열과 버퍼

숫자

기타 객체

API 함수

값 구축

문자열 변환과 포매팅

PyHash API

리플렉션

코덱 등록소와 지원 함수

코덱 조회 API

유니코드 인코딩 에러 처리기용 등록소 API

PyTime C API

Types

Clock Functions

Raw Clock Functions

Conversion functions

Support for Perf Maps

운영 체제 유틸리티

PyObject *PyOS_FSPath(PyObject *path)

Return value: New reference. Part of the Stable ABI since version 3.6.

Return the file system representation for path. If the object is a str or bytes object, then a new strong reference is returned. If the object implements the os.PathLike interface, then __fspath__() is returned as long as it is a str or bytes object. Otherwise TypeError is raised and NULL is returned.

Added in version 3.6.

int Py_FdIsInteractive(FILE *fp, const char *filename)

Return true (nonzero) if the standard I/O file fp with name filename is deemed interactive. This is the case for files for which isatty(fileno(fp)) is true. If the PyConfig.interactive is non-zero, this function also returns true if the filename pointer is NULL or if the name is equal to one of the strings '<stdin>' or '???'.

This function must not be called before Python is initialized.

void PyOS_BeforeFork()

Part of the Stable ABI on platforms with fork() since version 3.7.

프로세스 포크 전에 내부 상태를 준비하는 함수. fork()나 현재 프로세스를 복제하는 유사한 함수를 호출하기 전에 호출해야 합니다. fork()가 정의된 시스템에서만 사용 가능합니다.

경고

C fork() 호출은 (“메인” 인터프리터의) “메인” 스레드에서만 이루어져야 합니다. PyOS_BeforeFork()도 마찬가지입니다.

Added in version 3.7.

void PyOS_AfterFork_Parent()

Part of the Stable ABI on platforms with fork() since version 3.7.

프로세스 포크 후 일부 내부 상태를 갱신하는 함수. 프로세스 복제가 성공했는지와 관계없이, fork()나 현재 프로세스를 복제하는 유사한 함수를 호출한 후 부모 프로세스에서 호출해야 합니다. fork()가 정의된 시스템에서만 사용 가능합니다.

경고

C fork() 호출은 (“메인” 인터프리터의) “메인” 스레드에서만 이루어져야 합니다. PyOS_AfterFork_Parent()도 마찬가지입니다.

Added in version 3.7.

void PyOS_AfterFork_Child()

Part of the Stable ABI on platforms with fork() since version 3.7.

프로세스 포크 후 내부 인터프리터 상태를 갱신하는 함수. fork()나 현재 프로세스를 복제하는 유사한 함수를 호출한 후, 프로세스가 파이썬 인터프리터를 다시 호출할 가능성이 있으면 자식 프로세스에서 호출해야 합니다. fork()가 정의된 시스템에서만 사용 가능합니다.

경고

C fork() 호출은 (“메인” 인터프리터의) “메인” 스레드에서만 이루어져야 합니다. PyOS_AfterFork_Child()도 마찬가지입니다.

Added in version 3.7.

더 보기

os.register_at_fork()를 사용하면 PyOS_BeforeFork(), PyOS_AfterFork_Parent() 및 PyOS_AfterFork_Child()에서 호출될 사용자 정의 파이썬 함수를 등록 할 수 있습니다.

void PyOS_AfterFork()

Part of the Stable ABI on platforms with fork().

프로세스 포크 후 일부 내부 상태를 갱신하는 함수; 파이썬 인터프리터가 계속 사용된다면 새로운 프로세스에서 호출되어야 합니다. 새 실행 파일이 새 프로세스에 로드되면, 이 함수를 호출할 필요가 없습니다.

버전 3.7부터 폐지됨: 이 함수는 PyOS_AfterFork_Child()로 대체되었습니다.

int PyOS_CheckStack()

Part of the Stable ABI on platforms with USE_STACKCHECK since version 3.7.

Return true when the interpreter runs out of stack space. This is a reliable check, but is only available when USE_STACKCHECK is defined (currently on certain versions of Windows using the Microsoft Visual C++ compiler). USE_STACKCHECK will be defined automatically; you should never change the definition in your own code.

typedef void (*PyOS_sighandler_t)(int)

Part of the Stable ABI.

PyOS_sighandler_t PyOS_getsig(int i)

Part of the Stable ABI.

Return the current signal handler for signal i. This is a thin wrapper around either sigaction() or signal(). Do not call those functions directly!

PyOS_sighandler_t PyOS_setsig(int i, PyOS_sighandler_t h)

Part of the Stable ABI.

Set the signal handler for signal i to be h; return the old signal handler. This is a thin wrapper around either sigaction() or signal(). Do not call those functions directly!

wchar_t *Py_DecodeLocale(const char *arg, size_t *size)

Part of the Stable ABI since version 3.7.

경고

This function should not be called directly: use the PyConfig API with the PyConfig_SetBytesString() function which ensures that Python is preinitialized.

This function must not be called before Python is preinitialized and so that the LC_CTYPE locale is properly configured: see the Py_PreInitialize() function.

Decode a byte string from the filesystem encoding and error handler. If the error handler is surrogateescape error handler, undecodable bytes are decoded as characters in range U+DC80..U+DCFF; and if a byte sequence can be decoded as a surrogate character, the bytes are escaped using the surrogateescape error handler instead of decoding them.

새로 할당된 와이드 문자(wide character) 문자열에 대한 포인터를 반환합니다, 메모리를 해제하려면 PyMem_RawFree()를 사용하십시오. size가 NULL이 아니면, 널 문자를 제외한 와이드 문자 수를 *size에 기록합니다.

디코딩 에러나 메모리 할당 에러 시 NULL을 반환합니다. size가 NULL이 아니면, 메모리 에러 시 *size가 (size_t)-1로 설정되고, 디코딩 에러 시 (size_t)-2로 설정됩니다.

The filesystem encoding and error handler are selected by PyConfig_Read(): see filesystem_encoding and filesystem_errors members of PyConfig.

C 라이브러리에 버그가 없으면, 디코딩 에러가 발생하지 않아야 합니다.

문자열을 바이트열로 다시 인코딩하려면 Py_EncodeLocale() 함수를 사용하십시오.

더 보기

PyUnicode_DecodeFSDefaultAndSize()와 PyUnicode_DecodeLocaleAndSize() 함수.

Added in version 3.5.

버전 3.7에서 변경: The function now uses the UTF-8 encoding in the Python UTF-8 Mode.

버전 3.8에서 변경: The function now uses the UTF-8 encoding on Windows if PyPreConfig.legacy_windows_fs_encoding is zero;

char *Py_EncodeLocale(const wchar_t *text, size_t *error_pos)

Part of the Stable ABI since version 3.7.

Encode a wide character string to the filesystem encoding and error handler. If the error handler is surrogateescape error handler, surrogate characters in the range U+DC80..U+DCFF are converted to bytes 0x80..0xFF.

Return a pointer to a newly allocated byte string, use PyMem_Free() to free the memory. Return NULL on encoding error or memory allocation error.

error_pos가 NULL이 아니면, *error_pos는 성공 시 (size_t)-1로 설정되고, 인코딩 에러 시 유효하지 않은 문자의 인덱스로 설정됩니다.

The filesystem encoding and error handler are selected by PyConfig_Read(): see filesystem_encoding and filesystem_errors members of PyConfig.

바이트열을 와이드 문자 문자열로 다시 디코딩하려면 Py_DecodeLocale() 함수를 사용하십시오.

경고

This function must not be called before Python is preinitialized and so that the LC_CTYPE locale is properly configured: see the Py_PreInitialize() function.

더 보기

PyUnicode_EncodeFSDefault()와 PyUnicode_EncodeLocale() 함수.

Added in version 3.5.

버전 3.7에서 변경: The function now uses the UTF-8 encoding in the Python UTF-8 Mode.

버전 3.8에서 변경: The function now uses the UTF-8 encoding on Windows if PyPreConfig.legacy_windows_fs_encoding is zero.

시스템 함수

sys 모듈의 기능을 C 코드에서 액세스 할 수 있게 하는 유틸리티 함수입니다. 모두 내부 스레드 상태 구조체에 포함된 현재 인터프리터 스레드의 sys 모듈의 딕셔너리에 작동합니다.

PyObject *PySys_GetObject(const char *name)

Return value: Borrowed reference. Part of the Stable ABI.

sys 모듈에서 객체 name을 반환하거나, 존재하지 않으면 예외를 설정하지 않고 NULL을 반환합니다.

int PySys_SetObject(const char *name, PyObject *v)

Part of the Stable ABI.

v가 NULL이 아닌 한 sys 모듈의 name을 v로 설정합니다. NULL이면 name은 sys 모듈에서 삭제됩니다. 성공하면 0, 에러 시 -1을 반환합니다.

void PySys_ResetWarnOptions()

Part of the Stable ABI.

sys.warnoptions를 빈 리스트로 재설정합니다. 이 함수는 Py_Initialize() 이전에 호출할 수 있습니다.

Deprecated since version 3.13, will be removed in version 3.15: Clear sys.warnoptions and warnings.filters instead.

void PySys_WriteStdout(const char *format, ...)

Part of the Stable ABI.

format으로 기술되는 출력 문자열을 sys.stdout에 기록합니다. 잘림이 발생하더라도 예외는 발생하지 않습니다 (아래를 참조하십시오).

format은 포맷된 출력 문자열의 총 크기를 1000바이트 이하로 제한해야 합니다 – 1000바이트 이후에는, 출력 문자열이 잘립니다. 특히, 이것은 무제한 “%s” 포맷이 있어서는 안 됨을 의미합니다; “%.<N>s”를 사용하여 제한해야 합니다, 여기서 <N>은 <N>에 다른 포맷된 텍스트의 최대 크기를 더할 때 1000바이트를 초과하지 않도록 계산된 십진수입니다. 또한 “%f”도 주의하십시오, 아주 큰 숫자는 수백 자리를 인쇄할 수 있습니다.

문제가 발생하거나, sys.stdout가 설정되어 있지 않으면, 포맷된 메시지는 실제(C 수준) stdout에 기록됩니다.

void PySys_WriteStderr(const char *format, ...)

Part of the Stable ABI.

PySys_WriteStdout()과 같지만, 대신 sys.stderr이나 stderr에 씁니다.

void PySys_FormatStdout(const char *format, ...)

Part of the Stable ABI.

PySys_WriteStdout()과 유사한 함수이지만, 메시지를 PyUnicode_FromFormatV()를 사용하여 포맷하고 메시지를 임의의 길이로 자르지 않습니다.

Added in version 3.2.

void PySys_FormatStderr(const char *format, ...)

Part of the Stable ABI.

PySys_FormatStdout()과 같지만, 대신 sys.stderr이나 stderr에 씁니다.

Added in version 3.2.

PyObject *PySys_GetXOptions()

Return value: Borrowed reference. Part of the Stable ABI since version 3.7.

sys._xoptions와 유사하게, -X 옵션의 현재 딕셔너리를 반환합니다. 에러가 발생하면, NULL이 반환되고 예외가 설정됩니다.

Added in version 3.2.

int PySys_Audit(const char *event, const char *format, ...)

Part of the Stable ABI since version 3.13.

모든 활성 훅으로 감사 이벤트를 발생시킵니다. 성공 시 0을 반환하고 실패 시 예외를 설정하여 0이 아닌 값을 반환합니다.

The event string argument must not be NULL.

If any hooks have been added, format and other arguments will be used to construct a tuple to pass. Apart from N, the same format characters as used in Py_BuildValue() are available. If the built value is not a tuple, it will be added into a single-element tuple.

The N format option must not be used. It consumes a reference, but since there is no way to know whether arguments to this function will be consumed, using it may cause reference leaks.

Note that # format characters should always be treated as Py_ssize_t, regardless of whether PY_SSIZE_T_CLEAN was defined.

sys.audit()은 파이썬 코드와 동일한 기능을 수행합니다.

See also PySys_AuditTuple().

Added in version 3.8.

버전 3.8.2에서 변경: Require Py_ssize_t for # format characters. Previously, an unavoidable deprecation warning was raised.

int PySys_AuditTuple(const char *event, PyObject *args)

Part of the Stable ABI since version 3.13.

Similar to PySys_Audit(), but pass arguments as a Python object. args must be a tuple. To pass no arguments, args can be NULL.

Added in version 3.13.

int PySys_AddAuditHook(Py_AuditHookFunction hook, void *userData)

Append the callable hook to the list of active auditing hooks. Return zero on success and non-zero on failure. If the runtime has been initialized, also set an error on failure. Hooks added through this API are called for all interpreters created by the runtime.

userData 포인터는 훅 함수로 전달됩니다. 훅 함수는 다른 런타임에서 호출될 수 있어서, 이 포인터는 파이썬 상태를 직접 참조하면 안 됩니다.

이 함수는 Py_Initialize() 이전에 호출해도 안전합니다. 런타임 초기화 후 호출되면, 기존 감사 훅에 알리고 Exception에서 서브 클래싱 된 에러를 발생 시켜 조용히 연산을 중단할 수 있습니다 (다른 에러는 억제되지(silenced) 않습니다).

The hook function is always called with the GIL held by the Python interpreter that raised the event.

감사에 대한 자세한 설명은 PEP 578 [https://peps.python.org/pep-0578/]을 참조하십시오. 이벤트를 발생시키는 런타임과 표준 라이브러리의 함수는 감사 이벤트 표에 나열되어 있습니다. 자세한 내용은 각 함수 설명서에 있습니다.

If the interpreter is initialized, this function raises an auditing event sys.addaudithook with no arguments. If any existing hooks raise an exception derived from Exception, the new hook will not be added and the exception is cleared. As a result, callers cannot assume that their hook has been added unless they control all existing hooks.

typedef int (*Py_AuditHookFunction)(const char *event, PyObject *args, void *userData)

The type of the hook function. event is the C string event argument passed to PySys_Audit() or PySys_AuditTuple(). args is guaranteed to be a PyTupleObject. userData is the argument passed to PySys_AddAuditHook().

Added in version 3.8.

프로세스 제어

void Py_FatalError(const char *message)

Part of the Stable ABI.

Print a fatal error message and kill the process. No cleanup is performed. This function should only be invoked when a condition is detected that would make it dangerous to continue using the Python interpreter; e.g., when the object administration appears to be corrupted. On Unix, the standard C library function abort() is called which will attempt to produce a core file.

Py_LIMITED_API 매크로가 정의되어 있지 않은 한, Py_FatalError() 함수는 현재 함수의 이름을 자동으로 로그 하는 매크로로 대체됩니다.

버전 3.9에서 변경: 함수 이름을 자동으로 로그 합니다.

void Py_Exit(int status)

Part of the Stable ABI.

현재 프로세스를 종료합니다. 이것은 Py_FinalizeEx()를 호출한 다음 표준 C 라이브러리 함수 exit(status)를 호출합니다. Py_FinalizeEx()가 에러를 표시하면, 종료 상태는 120으로 설정됩니다.

버전 3.6에서 변경: 파이널리제이션에서의 에러가 더는 무시되지 않습니다.

int Py_AtExit(void (*func)())

Part of the Stable ABI.

Py_FinalizeEx()가 호출할 정리 함수를 등록합니다. 정리 함수는 인자 없이 호출되며 값을 반환하지 않아야 합니다. 최대 32개의 정리 함수를 등록할 수 있습니다. 등록이 성공하면, Py_AtExit()는 0을 반환합니다; 실패하면 -1을 반환합니다. 마지막에 등록된 정리 함수가 먼저 호출됩니다. 각 정리 함수는 최대 한 번 호출됩니다. 정리 함수 전에 파이썬의 내부 파이널리제이션이 완료되기 때문에, func에서 파이썬 API를 호출하면 안 됩니다.

모듈 임포트 하기

PyObject *PyImport_ImportModule(const char *name)

Return value: New reference. Part of the Stable ABI.

This is a wrapper around PyImport_Import() which takes a const char* as an argument instead of a PyObject*.

PyObject *PyImport_ImportModuleNoBlock(const char *name)

Return value: New reference. Part of the Stable ABI.

이 함수는 PyImport_ImportModule()의 폐지된 별칭입니다.

버전 3.3에서 변경: 이 기능은 다른 스레드가 임포트 잠금을 보유한 경우 즉시 실패했었습니다. 그러나 파이썬 3.3에서는, 잠금 방식이 대부분의 목적에서 모듈 단위 잠금으로 전환되었기 때문에, 이 함수의 특수한 동작은 더는 필요하지 않습니다.

Deprecated since version 3.13, will be removed in version 3.15: Use PyImport_ImportModule() instead.

PyObject *PyImport_ImportModuleEx(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist)

Return value: New reference.

모듈을 임포트 합니다. 내장 파이썬 함수 __import__()를 통해 가장 잘 설명할 수 있습니다.

반환 값은 임포트 된 모듈이나 최상위 패키지에 대한 새로운 참조, 또는 실패 시 예외가 설정된 NULL입니다. __import__()와 마찬가지로, 비어 있지 않은 fromlist가 제공되지 않는 한, 패키지의 서브 모듈이 요청되었을 때의 반환 값은 최상위 패키지입니다.

임포트 실패는 PyImport_ImportModule()처럼 불완전한 모듈 객체를 제거합니다.

PyObject *PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals, PyObject *locals, PyObject *fromlist, int level)

Return value: New reference. Part of the Stable ABI since version 3.7.

모듈을 임포트 합니다. 표준 __import__() 함수가 이 함수를 직접 호출하기 때문에, 내장 파이썬 함수 __import__()를 통해 가장 잘 설명할 수 있습니다.

반환 값은 임포트 된 모듈이나 최상위 패키지에 대한 새로운 참조, 또는 실패 시 예외가 설정된 NULL입니다. __import__()와 마찬가지로, 비어 있지 않은 fromlist가 제공되지 않는 한, 패키지의 서브 모듈이 요청되었을 때의 반환 값은 최상위 패키지입니다.

Added in version 3.3.

PyObject *PyImport_ImportModuleLevel(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist, int level)

Return value: New reference. Part of the Stable ABI.

PyImport_ImportModuleLevelObject()와 비슷하지만, name은 유니코드 객체 대신 UTF-8로 인코딩된 문자열입니다.

버전 3.3에서 변경: level의 음수 값은 더는 허용되지 않습니다.

PyObject *PyImport_Import(PyObject *name)

Return value: New reference. Part of the Stable ABI.

이것은 현재 “임포트 훅 함수”를 호출하는 고수준 인터페이스입니다 (명시적인 level 0을 사용하는데, 절대 임포트를 뜻합니다). 현재 전역의 __builtins__에 있는 __import__() 함수를 호출합니다. 이는 현재 환경에 설치된 임포트 훅을 사용하여 임포트가 수행됨을 의미합니다.

이 함수는 항상 절대 임포트를 사용합니다.

PyObject *PyImport_ReloadModule(PyObject *m)

Return value: New reference. Part of the Stable ABI.

모듈을 다시 로드(reload)합니다. 다시 로드된 모듈에 대한 참조를 반환하거나, 실패 시 예외가 설정된 NULL을 반환합니다 (이때 모듈은 여전히 존재합니다).

PyObject *PyImport_AddModuleRef(const char *name)

Return value: New reference. Part of the Stable ABI since version 3.13.

Return the module object corresponding to a module name.

The name argument may be of the form package.module. First check the modules dictionary if there’s one there, and if not, create a new one and insert it in the modules dictionary.

Return a strong reference to the module on success. Return NULL with an exception set on failure.

The module name name is decoded from UTF-8.

This function does not load or import the module; if the module wasn’t already loaded, you will get an empty module object. Use PyImport_ImportModule() or one of its variants to import a module. Package structures implied by a dotted name for name are not created if not already present.

Added in version 3.13.

PyObject *PyImport_AddModuleObject(PyObject *name)

Return value: Borrowed reference. Part of the Stable ABI since version 3.7.

Similar to PyImport_AddModuleRef(), but return a borrowed reference and name is a Python str object.

Added in version 3.3.

PyObject *PyImport_AddModule(const char *name)

Return value: Borrowed reference. Part of the Stable ABI.

Similar to PyImport_AddModuleRef(), but return a borrowed reference.

PyObject *PyImport_ExecCodeModule(const char *name, PyObject *co)

Return value: New reference. Part of the Stable ABI.

Given a module name (possibly of the form package.module) and a code object read from a Python bytecode file or obtained from the built-in function compile(), load the module. Return a new reference to the module object, or NULL with an exception set if an error occurred. name is removed from sys.modules in error cases, even if name was already in sys.modules on entry to PyImport_ExecCodeModule(). Leaving incompletely initialized modules in sys.modules is dangerous, as imports of such modules have no way to know that the module object is an unknown (and probably damaged with respect to the module author’s intents) state.

The module’s __spec__ and __loader__ will be set, if not set already, with the appropriate values. The spec’s loader will be set to the module’s __loader__ (if set) and to an instance of SourceFileLoader otherwise.

The module’s __file__ attribute will be set to the code object’s co_filename. If applicable, __cached__ will also be set.

이 함수는 이미 임포트 되었다면 모듈을 다시 로드합니다. 모듈을 다시 로드하는 의도된 방법은 PyImport_ReloadModule()을 참조하십시오.

name이 package.module 형식의 점으로 구분된 이름을 가리키면, 이미 만들어지지 않은 패키지 구조는 여전히 만들어지지 않습니다.

PyImport_ExecCodeModuleEx()와 PyImport_ExecCodeModuleWithPathnames()도 참조하십시오.

버전 3.12에서 변경: The setting of __cached__ and __loader__ is deprecated. See ModuleSpec for alternatives.

PyObject *PyImport_ExecCodeModuleEx(const char *name, PyObject *co, const char *pathname)

Return value: New reference. Part of the Stable ABI.

Like PyImport_ExecCodeModule(), but the __file__ attribute of the module object is set to pathname if it is non-NULL.

PyImport_ExecCodeModuleWithPathnames()도 참조하십시오.

PyObject *PyImport_ExecCodeModuleObject(PyObject *name, PyObject *co, PyObject *pathname, PyObject *cpathname)

Return value: New reference. Part of the Stable ABI since version 3.7.

Like PyImport_ExecCodeModuleEx(), but the __cached__ attribute of the module object is set to cpathname if it is non-NULL. Of the three functions, this is the preferred one to use.

Added in version 3.3.

버전 3.12에서 변경: Setting __cached__ is deprecated. See ModuleSpec for alternatives.

PyObject *PyImport_ExecCodeModuleWithPathnames(const char *name, PyObject *co, const char *pathname, const char *cpathname)

Return value: New reference. Part of the Stable ABI.

PyImport_ExecCodeModuleObject()와 유사하지만, name, pathname 및 cpathname은 UTF-8로 인코딩된 문자열입니다. pathname의 값이 NULL로 설정된 경우 어떤 값이 cpathname에서 와야하는지 알아내려고 합니다.

Added in version 3.2.

버전 3.3에서 변경: Uses imp.source_from_cache() in calculating the source path if only the bytecode path is provided.

버전 3.12에서 변경: No longer uses the removed imp module.

long PyImport_GetMagicNumber()

Part of the Stable ABI.

파이썬 바이트 코드 파일(일명 .pyc 파일)의 매직 번호(magic number)를 반환합니다. 매직 번호는 바이트 코드 파일의 처음 4바이트에 리틀 엔디안 바이트 순서로 존재해야 합니다. 에러 시 -1을 반환합니다.

버전 3.3에서 변경: 실패 시 -1을 반환합니다.

const char *PyImport_GetMagicTag()

Part of the Stable ABI.

PEP 3147 [https://peps.python.org/pep-3147/] 형식 파이썬 바이트 코드 파일 이름의 매직 태그 문자열을 반환합니다. sys.implementation.cache_tag의 값은 신뢰할 수 있고 이 함수 대신 사용해야 함에 유의하십시오.

Added in version 3.2.

PyObject *PyImport_GetModuleDict()

Return value: Borrowed reference. Part of the Stable ABI.

모듈 관리에 사용되는 딕셔너리(일명 sys.modules)를 반환합니다. 이것은 인터프리터마다 존재하는 변수임에 유의하십시오.

PyObject *PyImport_GetModule(PyObject *name)

Return value: New reference. Part of the Stable ABI since version 3.8.

주어진 이름으로 이미 임포트 된 모듈을 반환합니다. 모듈이 아직 임포트 되지 않았다면 NULL을 반환하지만 에러는 설정하지 않습니다. 조회에 실패하면 NULL을 반환하고 에러를 설정합니다.

Added in version 3.7.

PyObject *PyImport_GetImporter(PyObject *path)

Return value: New reference. Part of the Stable ABI.

Return a finder object for a sys.path/pkg.__path__ item path, possibly by fetching it from the sys.path_importer_cache dict. If it wasn’t yet cached, traverse sys.path_hooks until a hook is found that can handle the path item. Return None if no hook could; this tells our caller that the path based finder could not find a finder for this path item. Cache the result in sys.path_importer_cache. Return a new reference to the finder object.

int PyImport_ImportFrozenModuleObject(PyObject *name)

Part of the Stable ABI since version 3.7.

name이라는 이름의 프로즌 모듈(frozen module)을 로드합니다. 성공하면 1을, 모듈을 찾지 못하면 0을, 초기화에 실패하면 예외를 설정하고 -1을 반환합니다. 로드가 성공할 때 임포트 된 모듈에 액세스하려면 PyImport_ImportModule()을 사용하십시오. (잘못된 이름에 주의하십시오 — 이 함수는 모듈이 이미 임포트 되었을 때 다시 로드합니다.)

Added in version 3.3.

버전 3.4에서 변경: __file__ 어트리뷰트는 더는 모듈에 설정되지 않습니다.

int PyImport_ImportFrozenModule(const char *name)

Part of the Stable ABI.

PyImport_ImportFrozenModuleObject()와 비슷하지만, name은 유니코드 객체 대신 UTF-8로 인코딩된 문자열입니다.

struct _frozen

이것은 freeze 유틸리티(파이썬 소스 배포의 Tools/freeze/를 참조하십시오)가 생성한 프로즌 모듈 디스크립터를 위한 구조체 형 정의입니다. Include/import.h에 있는 정의는 다음과 같습니다:

struct _frozen {
    const char *name;
    const unsigned char *code;
    int size;
    bool is_package;
};

버전 3.11에서 변경: The new is_package field indicates whether the module is a package or not. This replaces setting the size field to a negative value.

const struct _frozen *PyImport_FrozenModules

This pointer is initialized to point to an array of _frozen records, terminated by one whose members are all NULL or zero. When a frozen module is imported, it is searched in this table. Third-party code could play tricks with this to provide a dynamically created collection of frozen modules.

int PyImport_AppendInittab(const char *name, PyObject *(*initfunc)(void))

Part of the Stable ABI.

기존의 내장 모듈 테이블에 단일 모듈을 추가합니다. 이것은 PyImport_ExtendInittab()을 감싸는 편리한 래퍼인데, 테이블을 확장할 수 없으면 -1을 반환합니다. 새 모듈은 name이라는 이름으로 임포트 될 수 있으며, initfunc 함수를 처음 시도한 임포트에서 호출되는 초기화 함수로 사용합니다. Py_Initialize() 전에 호출해야 합니다.

struct _inittab

Structure describing a single entry in the list of built-in modules. Programs which embed Python may use an array of these structures in conjunction with PyImport_ExtendInittab() to provide additional built-in modules. The structure consists of two members:

const char *name

The module name, as an ASCII encoded string.

PyObject *(*initfunc)(void)

Initialization function for a module built into the interpreter.

int PyImport_ExtendInittab(struct _inittab *newtab)

Add a collection of modules to the table of built-in modules. The newtab array must end with a sentinel entry which contains NULL for the name field; failure to provide the sentinel value can result in a memory fault. Returns 0 on success or -1 if insufficient memory could be allocated to extend the internal table. In the event of failure, no modules are added to the internal table. This must be called before Py_Initialize().

If Python is initialized multiple times, PyImport_AppendInittab() or PyImport_ExtendInittab() must be called before each Python initialization.

데이터 마샬링 지원

이러한 루틴은 C 코드가 marshal 모듈과 같은 데이터 형식을 사용하여 직렬화된 객체로 작업 할 수 있도록 합니다. 직렬화 형식으로 데이터를 쓰는 함수와 데이터를 다시 읽는 데 사용할 수 있는 추가 함수가 있습니다. 마샬링 된 데이터를 저장하는 데 사용되는 파일은 바이너리 모드로 열어야 합니다.

숫자 값은 최하위 바이트가 먼저 저장됩니다.

The module supports several versions of the data format; see the Python module documentation for details.

Py_MARSHAL_VERSION

The current format version. See marshal.version.

void PyMarshal_WriteLongToFile(long value, FILE *file, int version)

Marshal a long integer, value, to file. This will only write the least-significant 32 bits of value; regardless of the size of the native long type. version indicates the file format.

This function can fail, in which case it sets the error indicator. Use PyErr_Occurred() to check for that.

void PyMarshal_WriteObjectToFile(PyObject *value, FILE *file, int version)

파이썬 객체 value를 file로 마샬합니다. version은 파일 형식을 나타냅니다.

This function can fail, in which case it sets the error indicator. Use PyErr_Occurred() to check for that.

PyObject *PyMarshal_WriteObjectToString(PyObject *value, int version)

Return value: New reference.

마샬된 value 표현을 포함한 바이트열 객체를 반환합니다. version은 파일 형식을 나타냅니다.

다음 함수를 사용하면 마샬된 값을 다시 읽을 수 있습니다.

long PyMarshal_ReadLongFromFile(FILE *file)

Return a C long from the data stream in a FILE* opened for reading. Only a 32-bit value can be read in using this function, regardless of the native size of long.

에러 시, 적절한 예외(EOFError)를 설정하고 -1을 반환합니다.

int PyMarshal_ReadShortFromFile(FILE *file)

Return a C short from the data stream in a FILE* opened for reading. Only a 16-bit value can be read in using this function, regardless of the native size of short.

에러 시, 적절한 예외(EOFError)를 설정하고 -1을 반환합니다.

PyObject *PyMarshal_ReadObjectFromFile(FILE *file)

Return value: New reference.

Return a Python object from the data stream in a FILE* opened for reading.

에러 시, 적절한 예외(EOFError, ValueError 또는 TypeError)를 설정하고 NULL을 반환합니다.

PyObject *PyMarshal_ReadLastObjectFromFile(FILE *file)

Return value: New reference.

Return a Python object from the data stream in a FILE* opened for reading. Unlike PyMarshal_ReadObjectFromFile(), this function assumes that no further objects will be read from the file, allowing it to aggressively load file data into memory so that the de-serialization can operate from data in memory rather than reading a byte at a time from the file. Only use these variant if you are certain that you won’t be reading anything else from the file.

에러 시, 적절한 예외(EOFError, ValueError 또는 TypeError)를 설정하고 NULL을 반환합니다.

PyObject *PyMarshal_ReadObjectFromString(const char *data, Py_ssize_t len)

Return value: New reference.

data가 가리키는 len 바이트를 포함하는 바이트 버퍼의 데이터 스트림에서 파이썬 객체를 반환합니다.

에러 시, 적절한 예외(EOFError, ValueError 또는 TypeError)를 설정하고 NULL을 반환합니다.

인자 구문 분석과 값 구축

이 함수들은 자체 확장 함수와 메서드를 만들 때 유용합니다. 추가 정보와 예제는 파이썬 인터프리터 확장 및 내장에 있습니다.

설명된 이러한 함수 중 처음 세 개인 PyArg_ParseTuple(), PyArg_ParseTupleAndKeywords() 및 PyArg_Parse()는 모두 예상 인자에 관한 사항을 함수에 알리는 데 사용되는 포맷 문자열(format strings)을 사용합니다. 포맷 문자열은 이러한 각 함수에 대해 같은 문법을 사용합니다.

인자 구문 분석

포맷 문자열은 0개 이상의 “포맷 단위(format units)”로 구성됩니다. 포맷 단위는 하나의 파이썬 객체를 설명합니다; 일반적으로 단일 문자나 괄호로 묶인 포맷 단위 시퀀스입니다. 몇 가지 예외를 제외하고, 괄호로 묶인 시퀀스가 아닌 포맷 단위는 일반적으로 이러한 함수에 대한 단일 주소 인자에 대응합니다. 다음 설명에서, 인용된(quoted) 형식은 포맷 단위입니다; (둥근) 괄호 안의 항목은 포맷 단위와 일치하는 파이썬 객체 형입니다; [대괄호] 안의 항목은 주소를 전달해야 하는 C 변수의 형입니다.

문자열과 버퍼

참고

On Python 3.12 and older, the macro PY_SSIZE_T_CLEAN must be defined before including Python.h to use all # variants of formats (s#, y#, etc.) explained below. This is not necessary on Python 3.13 and later.

이러한 포맷을 사용하면 연속적인 메모리 청크로 객체에 액세스 할 수 있습니다. 반환된 유니코드나 바이트열 영역에 대한 원시 저장소를 제공할 필요가 없습니다.

달리 명시되지 않는 한, 버퍼는 NUL로 종료되지 않습니다.

There are three ways strings and buffers can be converted to C:

Formats such as y* and s* fill a Py_buffer structure. This locks the underlying buffer so that the caller can subsequently use the buffer even inside a Py_BEGIN_ALLOW_THREADS block without the risk of mutable data being resized or destroyed. As a result, you have to call PyBuffer_Release() after you have finished processing the data (or in any early abort case).

The es, es#, et and et# formats allocate the result buffer. You have to call PyMem_Free() after you have finished processing the data (or in any early abort case).

Other formats take a str or a read-only bytes-like object, such as bytes, and provide a const char * pointer to its buffer. In this case the buffer is “borrowed”: it is managed by the corresponding Python object, and shares the lifetime of this object. You won’t have to release any memory yourself.

To ensure that the underlying buffer may be safely borrowed, the object’s PyBufferProcs.bf_releasebuffer field must be NULL. This disallows common mutable objects such as bytearray, but also some read-only objects such as memoryview of bytes.

Besides this bf_releasebuffer requirement, there is no check to verify whether the input object is immutable (e.g. whether it would honor a request for a writable buffer, or whether another thread can mutate the data).

s (str) [const char *]

유니코드 객체를 문자열에 대한 C 포인터로 변환합니다. 기존 문자열에 대한 포인터는 여러분이 주소를 전달한 문자 포인터 변수에 저장됩니다. C 문자열은 NUL로 종료됩니다. 파이썬 문자열은 내장된 널 코드 포인트를 포함하지 않아야 합니다; 그렇다면 ValueError 예외가 발생합니다. 유니코드 객체는 'utf-8' 인코딩을 사용하여 C 문자열로 변환됩니다. 이 변환이 실패하면, UnicodeError가 발생합니다.

참고

이 포맷은 바이트열류 객체를 받아들이지 않습니다. 파일 시스템 경로를 받아들이고 이를 C 문자열로 변환하려면, PyUnicode_FSConverter()를 converter로 O& 포맷을 사용하는 것이 좋습니다.

버전 3.5에서 변경: 이전에는, 파이썬 문자열에서 내장된 널 코드 포인트가 발견되면 TypeError가 발생했습니다.

s* (str 또는 바이트열류 객체) [Py_buffer]

이 포맷은 바이트열류 객체뿐만 아니라 유니코드 객체를 받아들입니다. 호출자가 제공한 Py_buffer 구조체를 채웁니다. 이 경우 결과 C 문자열은 내장된 NUL 바이트를 포함할 수 있습니다. 유니코드 객체는 'utf-8' 인코딩을 사용하여 C 문자열로 변환됩니다.

s# (str, read-only bytes-like object) [const char *, Py_ssize_t]

Like s*, except that it provides a borrowed buffer. The result is stored into two C variables, the first one a pointer to a C string, the second one its length. The string may contain embedded null bytes. Unicode objects are converted to C strings using 'utf-8' encoding.

z (str 또는 None) [const char *]

s와 비슷하지만, 파이썬 객체가 None일 수도 있는데, 이 경우 C 포인터가 NULL로 설정됩니다.

z* (str, 바이트열류 객체 또는 None) [Py_buffer]

s*와 비슷하지만, 파이썬 객체는 None일 수도 있습니다, 이 경우 Py_buffer 구조체의 buf 멤버가 NULL로 설정됩니다.

z# (str, read-only bytes-like object or None) [const char *, Py_ssize_t]

s#와 비슷하지만, 파이썬 객체는 None일 수도 있습니다, 이 경우 C 포인터가 NULL로 설정됩니다.

y (읽기 전용 바이트열류 객체) [const char *]

This format converts a bytes-like object to a C pointer to a borrowed character string; it does not accept Unicode objects. The bytes buffer must not contain embedded null bytes; if it does, a ValueError exception is raised.

버전 3.5에서 변경: 이전에는, 바이트열 버퍼에서 내장 널 바이트가 발견되면 TypeError가 발생했습니다.

y* (바이트열류 객체) [Py_buffer]

s*의 이 변형은 유니코드 객체가 아니라 바이트열류 객체만 받아들입니다. 바이너리 데이터를 받아들이는 권장 방법입니다.

y# (read-only bytes-like object) [const char *, Py_ssize_t]

s#의 이 변형은 유니코드 객체가 아니라 바이트열류 객체만 받아들입니다.

S (bytes) [PyBytesObject *]

Requires that the Python object is a bytes object, without attempting any conversion. Raises TypeError if the object is not a bytes object. The C variable may also be declared as PyObject*.

Y (bytearray) [PyByteArrayObject *]

Requires that the Python object is a bytearray object, without attempting any conversion. Raises TypeError if the object is not a bytearray object. The C variable may also be declared as PyObject*.

U (str) [PyObject *]

Requires that the Python object is a Unicode object, without attempting any conversion. Raises TypeError if the object is not a Unicode object. The C variable may also be declared as PyObject*.

w* (읽기-쓰기 바이트열류 객체) [Py_buffer]

이 포맷은 읽기-쓰기 버퍼 인터페이스를 구현하는 모든 객체를 허용합니다. 호출자가 제공한 Py_buffer 구조체를 채웁니다. 버퍼에는 내장 널 바이트가 포함될 수 있습니다. 호출자는 버퍼로 할 일을 마치면 PyBuffer_Release()를 호출해야 합니다.

es (str) [const char *encoding, char **buffer]

s의 이 변형은 유니코드를 문자 버퍼로 인코딩하는 데 사용됩니다. 내장 NUL 바이트가 포함되지 않은 인코딩된 데이터에 대해서만 작동합니다.

This format requires two arguments. The first is only used as input, and must be a const char* which points to the name of an encoding as a NUL-terminated string, or NULL, in which case 'utf-8' encoding is used. An exception is raised if the named encoding is not known to Python. The second argument must be a char**; the value of the pointer it references will be set to a buffer with the contents of the argument text. The text will be encoded in the encoding specified by the first argument.

PyArg_ParseTuple()은 필요한 크기의 버퍼를 할당하고, 인코딩된 데이터를 이 버퍼에 복사하고 새로 할당된 스토리지를 참조하도록 *buffer를 조정합니다. 호출자는 사용 후에 할당된 버퍼를 해제하기 위해 PyMem_Free()를 호출해야 합니다.

et (str, bytes 또는 bytearray) [const char *encoding, char **buffer]

바이트 문자열 객체를 다시 코딩하지 않고 통과시킨다는 점을 제외하면 es와 같습니다. 대신, 구현은 바이트 문자열 객체가 매개 변수로 전달된 인코딩을 사용한다고 가정합니다.

es# (str) [const char *encoding, char **buffer, Py_ssize_t *buffer_length]

s#의 이 변형은 유니코드를 문자 버퍼로 인코딩하는 데 사용됩니다. es 포맷과 달리, 이 변형은 NUL 문자를 포함하는 입력 데이터를 허용합니다.

It requires three arguments. The first is only used as input, and must be a const char* which points to the name of an encoding as a NUL-terminated string, or NULL, in which case 'utf-8' encoding is used. An exception is raised if the named encoding is not known to Python. The second argument must be a char**; the value of the pointer it references will be set to a buffer with the contents of the argument text. The text will be encoded in the encoding specified by the first argument. The third argument must be a pointer to an integer; the referenced integer will be set to the number of bytes in the output buffer.

두 가지 작동 모드가 있습니다:

*buffer가 NULL 포인터를 가리키면, 함수는 필요한 크기의 버퍼를 할당하고, 이 버퍼로 인코딩된 데이터를 복사하고 *buffer를 새로 할당된 스토리지를 참조하도록 설정합니다. 호출자는 사용 후 할당된 버퍼를 해제하기 위해 PyMem_Free()를 호출해야 합니다.

*buffer가 NULL이 아닌 포인터를 가리키면 (이미 할당된 버퍼), PyArg_ParseTuple()은 이 위치를 버퍼로 사용하고 *buffer_length의 초깃값을 버퍼 크기로 해석합니다. 그런 다음 인코딩된 데이터를 버퍼에 복사하고 NUL 종료합니다. 버퍼가 충분히 크지 않으면, ValueError가 설정됩니다.

두 경우 모두, *buffer_length는 후행 NUL 바이트를 제외한 인코딩된 데이터의 길이로 설정됩니다.

et# (str, bytes or bytearray) [const char *encoding, char **buffer, Py_ssize_t *buffer_length]

바이트 문자열 객체를 다시 코딩하지 않고 통과시킨다는 점을 제외하면 es#와 같습니다. 대신, 구현은 바이트 문자열 객체가 매개 변수로 전달된 인코딩을 사용한다고 가정합니다.

버전 3.12에서 변경: u, u#, Z, and Z# are removed because they used a legacy Py_UNICODE* representation.

숫자

b (int) [unsigned char]

Convert a nonnegative Python integer to an unsigned tiny int, stored in a C unsigned char.

B (int) [unsigned char]

Convert a Python integer to a tiny int without overflow checking, stored in a C unsigned char.

h (int) [short int]

Convert a Python integer to a C short int.

H (int) [unsigned short int]

Convert a Python integer to a C unsigned short int, without overflow checking.

i (int) [int]

Convert a Python integer to a plain C int.

I (int) [unsigned int]

Convert a Python integer to a C unsigned int, without overflow checking.

l (int) [long int]

Convert a Python integer to a C long int.

k (int) [unsigned long]

Convert a Python integer to a C unsigned long without overflow checking.

L (int) [long long]

Convert a Python integer to a C long long.

K (int) [unsigned long long]

Convert a Python integer to a C unsigned long long without overflow checking.

n (int) [Py_ssize_t]

파이썬 정수를 C Py_ssize_t로 변환합니다.

c (길이 1의 bytes 또는 bytearray) [char]

Convert a Python byte, represented as a bytes or bytearray object of length 1, to a C char.

버전 3.3에서 변경: bytearray 객체를 허용합니다.

C (길이 1의 str) [int]

Convert a Python character, represented as a str object of length 1, to a C int.

f (float) [float]

Convert a Python floating-point number to a C float.

d (float) [double]

Convert a Python floating-point number to a C double.

D (complex) [Py_complex]

파이썬 복소수를 C Py_complex 구조체로 변환합니다.

기타 객체

O (object) [PyObject *]

Store a Python object (without any conversion) in a C object pointer. The C program thus receives the actual object that was passed. A new strong reference to the object is not created (i.e. its reference count is not increased). The pointer stored is not NULL.

O! (object) [typeobject, PyObject *]

Store a Python object in a C object pointer. This is similar to O, but takes two C arguments: the first is the address of a Python type object, the second is the address of the C variable (of type PyObject*) into which the object pointer is stored. If the Python object does not have the required type, TypeError is raised.

O& (object) [converter, anything]

Convert a Python object to a C variable through a converter function. This takes two arguments: the first is a function, the second is the address of a C variable (of arbitrary type), converted to void*. The converter function in turn is called as follows:

status = converter(object, address);

where object is the Python object to be converted and address is the void* argument that was passed to the PyArg_Parse* function. The returned status should be 1 for a successful conversion and 0 if the conversion has failed. When the conversion fails, the converter function should raise an exception and leave the content of address unmodified.

converter가 Py_CLEANUP_SUPPORTED를 반환하면, 인자 구문 분석이 결국 실패하면 두 번째로 호출되어 변환기에 이미 할당된 메모리를 해제할 기회를 제공할 수 있습니다. 이 두 번째 호출에서, object 매개 변수는 NULL이 됩니다; address는 원래 호출과 같은 값을 갖습니다.

버전 3.1에서 변경: Py_CLEANUP_SUPPORTED가 추가되었습니다.

p (bool) [int]

전달된 값의 논리값을 테스트(불리언 predicate)하고 결과를 동등한 C 참/거짓 정숫값으로 변환합니다. 표현식이 참이면 int를 1로, 거짓이면 0으로 설정합니다. 모든 유효한 파이썬 값을 허용합니다. 파이썬이 논리값을 테스트하는 방법에 대한 자세한 내용은 논리값 검사를 참조하십시오.

Added in version 3.3.

(items) (tuple) [matching-items]

객체는 길이가 items에 있는 포맷 단위의 수인 파이썬 시퀀스여야 합니다. C 인자들은 items의 개별 포맷 단위에 대응해야 합니다. 시퀀스의 포맷 단위는 중첩될 수 있습니다.

It is possible to pass “long” integers (integers whose value exceeds the platform’s LONG_MAX) however no proper range checking is done — the most significant bits are silently truncated when the receiving field is too small to receive the value (actually, the semantics are inherited from downcasts in C — your mileage may vary).

몇 가지 다른 문자는 포맷 문자열에서 의미가 있습니다. 중첩된 괄호 안에서는 나타날 수 없습니다. 그들은:

|

파이썬 인자 리스트의 나머지 인자가 선택 사항임을 나타냅니다. 선택적 인자에 해당하는 C 변수는 기본값으로 초기화되어야 합니다 — 선택적 인자가 지정되지 않을 때, PyArg_ParseTuple()은 해당 C 변수의 내용을 건드리지 않습니다.

$

PyArg_ParseTupleAndKeywords() 전용: 파이썬 인자 리스트의 나머지 인자가 키워드 전용임을 나타냅니다. 현재, 모든 키워드 전용 인자는 선택적 인자여야 하므로, |는 항상 포맷 문자열에서 $ 앞에 지정되어야 합니다.

Added in version 3.3.

:

포맷 단위 리스트는 여기에서 끝납니다; 콜론 뒤의 문자열은 에러 메시지에서 함수 이름으로 사용됩니다 (PyArg_ParseTuple()이 발생시키는 예외의 “연관된 값”).

;

포맷 단위 리스트는 여기에서 끝납니다; 세미콜론 뒤의 문자열은 기본 에러 메시지의 에러 메시지 대신 에러 메시지로 사용됩니다. :와 ;는 서로를 배제합니다.

Note that any Python object references which are provided to the caller are borrowed references; do not release them (i.e. do not decrement their reference count)!

이러한 함수에 전달되는 추가 인자는 포맷 문자열에 의해 형이 결정되는 변수의 주소여야 합니다; 이들은 입력 튜플의 값을 저장하는 데 사용됩니다. 위의 포맷 단위 리스트에서 설명된 대로, 이러한 매개 변수가 입력값으로 사용되는 몇 가지 경우가 있습니다; 이 경우 해당 포맷 단위에 대해 지정된 것과 일치해야 합니다.

For the conversion to succeed, the arg object must match the format and the format must be exhausted. On success, the PyArg_Parse* functions return true, otherwise they return false and raise an appropriate exception. When the PyArg_Parse* functions fail due to conversion failure in one of the format units, the variables at the addresses corresponding to that and the following format units are left untouched.

API 함수

int PyArg_ParseTuple(PyObject *args, const char *format, ...)

Part of the Stable ABI.

위치 매개 변수만 지역 변수로 취하는 함수의 매개 변수를 구문 분석합니다. 성공하면 참을 반환합니다; 실패하면, 거짓을 반환하고 적절한 예외를 발생시킵니다.

int PyArg_VaParse(PyObject *args, const char *format, va_list vargs)

Part of the Stable ABI.

가변 개수의 인자가 아닌 va_list를 받아들인다는 점을 제외하면, PyArg_ParseTuple()과 동일합니다.

int PyArg_ParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *const *keywords, ...)

Part of the Stable ABI.

Parse the parameters of a function that takes both positional and keyword parameters into local variables. The keywords argument is a NULL-terminated array of keyword parameter names specified as null-terminated ASCII or UTF-8 encoded C strings. Empty names denote positional-only parameters. Returns true on success; on failure, it returns false and raises the appropriate exception.

참고

The keywords parameter declaration is char *const* in C and const char *const* in C++. This can be overridden with the PY_CXX_CONST macro.

버전 3.6에서 변경: 위치-전용 매개 변수에 대한 지원이 추가되었습니다.

버전 3.13에서 변경: The keywords parameter has now type char *const* in C and const char *const* in C++, instead of char**. Added support for non-ASCII keyword parameter names.

int PyArg_VaParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *const *keywords, va_list vargs)

Part of the Stable ABI.

가변 개수의 인자가 아닌 va_list를 받아들인다는 점을 제외하면, PyArg_ParseTupleAndKeywords() 와 동일합니다.

int PyArg_ValidateKeywordArguments(PyObject*)

Part of the Stable ABI.

키워드 인자 딕셔너리의 키가 문자열인지 확인합니다. PyArg_ParseTupleAndKeywords() 가 사용되지 않는 경우에만 필요합니다, 여기서는 이미 이 검사를 수행하기 때문입니다.

Added in version 3.2.

int PyArg_Parse(PyObject *args, const char *format, ...)

Part of the Stable ABI.

Parse the parameter of a function that takes a single positional parameter into a local variable. Returns true on success; on failure, it returns false and raises the appropriate exception.

Example:

// Function using METH_O calling convention
static PyObject*
my_function(PyObject *module, PyObject *arg)
{
    int value;
    if (!PyArg_Parse(arg, "i:my_function", &value)) {
        return NULL;
    }
    // ... use value ...
}

int PyArg_UnpackTuple(PyObject *args, const char *name, Py_ssize_t min, Py_ssize_t max, ...)

Part of the Stable ABI.

A simpler form of parameter retrieval which does not use a format string to specify the types of the arguments. Functions which use this method to retrieve their parameters should be declared as METH_VARARGS in function or method tables. The tuple containing the actual parameters should be passed as args; it must actually be a tuple. The length of the tuple must be at least min and no more than max; min and max may be equal. Additional arguments must be passed to the function, each of which should be a pointer to a PyObject* variable; these will be filled in with the values from args; they will contain borrowed references. The variables which correspond to optional parameters not given by args will not be filled in; these should be initialized by the caller. This function returns true on success and false if args is not a tuple or contains the wrong number of elements; an exception will be set if there was a failure.

This is an example of the use of this function, taken from the sources for the _weakref helper module for weak references:

static PyObject *
weakref_ref(PyObject *self, PyObject *args)
{
    PyObject *object;
    PyObject *callback = NULL;
    PyObject *result = NULL;

    if (PyArg_UnpackTuple(args, "ref", 1, 2, &object, &callback)) {
        result = PyWeakref_NewRef(object, callback);
    }
    return result;
}

이 예제에서 PyArg_UnpackTuple()에 대한 호출은 PyArg_ParseTuple()에 대한 다음 호출과 전적으로 동등합니다:

PyArg_ParseTuple(args, "O|O:ref", &object, &callback)

PY_CXX_CONST

The value to be inserted, if any, before char *const* in the keywords parameter declaration of PyArg_ParseTupleAndKeywords() and PyArg_VaParseTupleAndKeywords(). Default empty for C and const for C++ (const char *const*). To override, define it to the desired value before including Python.h.

Added in version 3.13.

값 구축

PyObject *Py_BuildValue(const char *format, ...)

Return value: New reference. Part of the Stable ABI.

Create a new value based on a format string similar to those accepted by the PyArg_Parse* family of functions and a sequence of values. Returns the value or NULL in the case of an error; an exception will be raised if NULL is returned.

Py_BuildValue()는 항상 튜플을 구축하지는 않습니다. 포맷 문자열에 둘 이상의 포맷 단위가 포함되었을 때만 튜플을 구축합니다. 포맷 문자열이 비어 있으면, None을 반환합니다; 정확히 하나의 포맷 단위를 포함하면, 해당 포맷 단위가 기술하는 객체가 무엇이건 반환합니다. 크기가 0이나 1인 튜플을 반환하도록 하려면, 포맷 문자열을 괄호로 묶으십시오.

s와 s# 포맷의 경우처럼, 메모리 버퍼가 데이터를 빌드 객체에 제공하기 위해 매개 변수로 전달될 때, 필요한 데이터가 복사됩니다. 호출자가 제공하는 버퍼는 Py_BuildValue()가 만든 객체에 의해 참조되지 않습니다. 즉, 여러분의 코드가 malloc()을 호출하고 할당된 메모리를 Py_BuildValue()에 전달하면, 인단 Py_BuildValue()가 반환되면 여러분이 코드가 해당 메모리에 대해 free()를 호출해야 합니다.

다음 설명에서, 인용된 형식은 포맷 단위입니다; (둥근) 괄호 안의 항목은 포맷 단위가 반환할 파이썬 객체 형입니다; [대괄호] 안의 항목은 전달할 C 값의 형입니다.

문자 스페이스, 탭, 콜론 및 쉼표는 포맷 문자열에서 무시됩니다 (하지만 s#와 같은 포맷 단위 내에서는 아닙니다). 이것은 긴 포맷 문자열을 좀 더 읽기 쉽게 만드는 데 사용할 수 있습니다.

s (str 또는 None) [const char *]

'utf-8' 인코딩을 사용하여 널-종료 C 문자열을 파이썬 str 객체로 변환합니다. C 문자열 포인터가 NULL이면, None이 사용됩니다.

s# (str or None) [const char *, Py_ssize_t]

'utf-8' 인코딩을 사용하여 C 문자열과 그 길이를 파이썬 str 객체로 변환합니다. C 문자열 포인터가 NULL이면, 길이가 무시되고 None이 반환됩니다.

y (bytes) [const char *]

이것은 C 문자열을 파이썬 bytes 객체로 변환합니다. C 문자열 포인터가 NULL이면, None이 반환됩니다.

y# (bytes) [const char *, Py_ssize_t]

이것은 C 문자열과 그 길이를 파이썬 객체로 변환합니다. C 문자열 포인터가 NULL이면, None이 반환됩니다.

z (str 또는 None) [const char *]

s와 같습니다.

z# (str or None) [const char *, Py_ssize_t]

s#과 같습니다.

u (str) [const wchar_t *]

유니코드 (UTF-16 또는 UCS-4) 데이터의 널-종료 wchar_t 버퍼를 파이썬 유니코드 객체로 변환합니다. 유니코드 버퍼 포인터가 NULL이면, None이 반환됩니다.

u# (str) [const wchar_t *, Py_ssize_t]

유니코드 (UTF-16 또는 UCS-4) 데이터 버퍼와 그 길이를 파이썬 유니코드 객체로 변환합니다. 유니코드 버퍼 포인터가 NULL이면, 길이가 무시되고 None이 반환됩니다.

U (str 또는 None) [const char *]

s와 같습니다.

U# (str or None) [const char *, Py_ssize_t]

s#과 같습니다.

i (int) [int]

Convert a plain C int to a Python integer object.

b (int) [char]

Convert a plain C char to a Python integer object.

h (int) [short int]

Convert a plain C short int to a Python integer object.

l (int) [long int]

Convert a C long int to a Python integer object.

B (int) [unsigned char]

Convert a C unsigned char to a Python integer object.

H (int) [unsigned short int]

Convert a C unsigned short int to a Python integer object.

I (int) [unsigned int]

Convert a C unsigned int to a Python integer object.

k (int) [unsigned long]

Convert a C unsigned long to a Python integer object.

L (int) [long long]

Convert a C long long to a Python integer object.

K (int) [unsigned long long]

Convert a C unsigned long long to a Python integer object.

n (int) [Py_ssize_t]

C Py_ssize_t를 파이썬 정수로 변환합니다.

c (길이 1의 bytes) [char]

Convert a C int representing a byte to a Python bytes object of length 1.

C (길이 1의 str) [int]

Convert a C int representing a character to Python str object of length 1.

d (float) [double]

Convert a C double to a Python floating-point number.

f (float) [float]

Convert a C float to a Python floating-point number.

D (complex) [Py_complex *]

C Py_complex 구조체를 파이썬 복소수로 변환합니다.

O (object) [PyObject *]

Pass a Python object untouched but create a new strong reference to it (i.e. its reference count is incremented by one). If the object passed in is a NULL pointer, it is assumed that this was caused because the call producing the argument found an error and set an exception. Therefore, Py_BuildValue() will return NULL but won’t raise an exception. If no exception has been raised yet, SystemError is set.

S (object) [PyObject *]

O와 같습니다.

N (object) [PyObject *]

Same as O, except it doesn’t create a new strong reference. Useful when the object is created by a call to an object constructor in the argument list.

O& (object) [converter, anything]

Convert anything to a Python object through a converter function. The function is called with anything (which should be compatible with void*) as its argument and should return a “new” Python object, or NULL if an error occurred.

(items) (tuple) [matching-items]

C값의 시퀀스를 항목 수가 같은 파이썬 튜플로 변환합니다.

[items] (list) [matching-items]

C값의 시퀀스를 항목 수가 같은 파이썬 리스트로 변환합니다.

{items} (dict) [matching-items]

C값의 시퀀스를 파이썬 딕셔너리로 변환합니다. 연속된 C 값의 각 쌍은 딕셔너리에 하나의 항목을 추가하여, 각각 키와 값으로 사용됩니다.

포맷 문자열에 에러가 있으면, SystemError 예외가 설정되고 NULL이 반환됩니다.

PyObject *Py_VaBuildValue(const char *format, va_list vargs)

Return value: New reference. Part of the Stable ABI.

가변 개수의 인자가 아닌 va_list를 받아들인다는 점을 제외하면, Py_BuildValue()와 동일합니다.

문자열 변환과 포매팅

숫자 변환과 포맷된 문자열 출력을 위한 함수.

int PyOS_snprintf(char *str, size_t size, const char *format, ...)

Part of the Stable ABI.

포맷 문자열 format 과 추가 인자에 따라 size 바이트를 넘지 않도록 str로 출력합니다. 유닉스 매뉴얼 페이지 snprintf(3) [https://manpages.debian.org/snprintf(3)]를 보십시오.

int PyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)

Part of the Stable ABI.

포맷 문자열 format 과 가변 인자 목록 va에 따라 size 바이트를 넘지 않도록 str로 출력합니다. 유닉스 매뉴얼 페이지 vsnprintf(3) [https://manpages.debian.org/vsnprintf(3)]를 보십시오.

PyOS_snprintf()와 PyOS_vsnprintf()는 표준 C 라이브러리 함수 snprintf()와 vsnprintf()를 감쌉니다. 그들의 목적은 경계 조건에서 표준 C 함수가 제공하지 않는 수준의 일관된 동작을 보장하는 것입니다.

The wrappers ensure that str[size-1] is always '\0' upon return. They never write more than size bytes (including the trailing '\0') into str. Both functions require that str != NULL, size > 0, format != NULL and size < INT_MAX. Note that this means there is no equivalent to the C99 n = snprintf(NULL, 0, ...) which would determine the necessary buffer size.

이 함수들의 반환 값(rv)은 다음과 같이 해석되어야 합니다:

0 <= rv < size 일 때, 출력 변환에 성공했으며 rv 문자가 str에 기록되었습니다 (str[rv]의 후행 '\0' 바이트 제외).

rv >= size 일 때, 출력 변환이 잘렸고 성공하려면 rv + 1 바이트의 버퍼가 필요합니다. str[size-1]은 이때 '\0'입니다.

rv < 0 일 때, “뭔가 나쁜 일이 일어났습니다.” 이때도 str[size-1]은 '\0'이지만, str의 나머지는 정의되지 않습니다. 에러의 정확한 원인은 하부 플랫폼에 따라 다릅니다.

다음 함수는 로케일 독립적인 문자열에서 숫자로의 변환을 제공합니다.

unsigned long PyOS_strtoul(const char *str, char **ptr, int base)

Part of the Stable ABI.

Convert the initial part of the string in str to an unsigned long value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0.

Leading white space and case of characters are ignored. If base is zero it looks for a leading 0b, 0o or 0x to tell which base. If these are absent it defaults to 10. Base must be 0 or between 2 and 36 (inclusive). If ptr is non-NULL it will contain a pointer to the end of the scan.

If the converted value falls out of range of corresponding return type, range error occurs (errno is set to ERANGE) and ULONG_MAX is returned. If no conversion can be performed, 0 is returned.

See also the Unix man page strtoul(3) [https://manpages.debian.org/strtoul(3)].

Added in version 3.2.

long PyOS_strtol(const char *str, char **ptr, int base)

Part of the Stable ABI.

Convert the initial part of the string in str to an long value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0.

Same as PyOS_strtoul(), but return a long value instead and LONG_MAX on overflows.

See also the Unix man page strtol(3) [https://manpages.debian.org/strtol(3)].

Added in version 3.2.

double PyOS_string_to_double(const char *s, char **endptr, PyObject *overflow_exception)

Part of the Stable ABI.

Convert a string s to a double, raising a Python exception on failure. The set of accepted strings corresponds to the set of strings accepted by Python’s float() constructor, except that s must not have leading or trailing whitespace. The conversion is independent of the current locale.

endptr이 NULL이면, 전체 문자열을 변환합니다. 문자열이 부동 소수점 숫자의 유효한 표현이 아니면 ValueError를 발생시키고 -1.0을 반환합니다.

endptr이 NULL이 아니면, 가능한 한 많은 문자열을 변환하고 *endptr이 변환되지 않은 첫 번째 문자를 가리키도록 설정합니다. 문자열의 초기 세그먼트가 부동 소수점 숫자의 유효한 표현이 아니면, *endptr이 문자열의 시작을 가리키도록 설정하고, ValueError를 발생시키고 -1.0을 반환합니다.

If s represents a value that is too large to store in a float (for example, "1e500" is such a string on many platforms) then if overflow_exception is NULL return Py_INFINITY (with an appropriate sign) and don’t set any exception. Otherwise, overflow_exception must point to a Python exception object; raise that exception and return -1.0. In both cases, set *endptr to point to the first character after the converted value.

변환 중 다른 에러가 발생하면 (예를 들어 메모리 부족 에러), 적절한 파이썬 예외를 설정하고 -1.0을 반환합니다.

Added in version 3.1.

char *PyOS_double_to_string(double val, char format_code, int precision, int flags, int *ptype)

Part of the Stable ABI.

Convert a double val to a string using supplied format_code, precision, and flags.

format_code는 'e', 'E', 'f', 'F', 'g', 'G' 또는 'r' 중 하나여야 합니다. 'r'의 경우, 제공된 precision은 0이어야 하며 무시됩니다. 'r' 포맷 코드는 표준 repr() 형식을 지정합니다.

flags는 Py_DTSF_SIGN, Py_DTSF_ADD_DOT_0 또는 Py_DTSF_ALT 값을 0개 이상 함께 or 할 수 있습니다:

Py_DTSF_SIGN은 val가 음수가 아닐 때도 항상 반환된 문자열 앞에 부호 문자가 오는 것을 뜻합니다.

Py_DTSF_ADD_DOT_0은 반환된 문자열이 정수처럼 보이지 않도록 하는 것을 뜻합니다.

Py_DTSF_ALT는 “대체” 포매팅 규칙을 적용하는 것을 뜻합니다. 자세한 내용은 PyOS_snprintf() '#' 지정자에 대한 설명서를 참조하십시오.

ptype이 NULL이 아니면, 포인터가 가리키는 값은 Py_DTST_FINITE, Py_DTST_INFINITE 또는 Py_DTST_NAN 중 하나로 설정되어, val가 각각 유한 수, 무한 수 또는 NaN임을 나타냅니다.

반환 값은 변환된 문자열이 있는 buffer에 대한 포인터이거나, 변환에 실패하면 NULL입니다. 호출자는 PyMem_Free()를 호출하여 반환된 문자열을 해제해야 합니다.

Added in version 3.1.

int PyOS_stricmp(const char *s1, const char *s2)

Case insensitive comparison of strings. The function works almost identically to strcmp() except that it ignores the case.

int PyOS_strnicmp(const char *s1, const char *s2, Py_ssize_t size)

Case insensitive comparison of strings. The function works almost identically to strncmp() except that it ignores the case.

PyHash API

See also the PyTypeObject.tp_hash member and 숫자 형의 해싱.

type Py_hash_t

Hash value type: signed integer.

Added in version 3.2.

type Py_uhash_t

Hash value type: unsigned integer.

Added in version 3.2.

PyHASH_MODULUS

The Mersenne prime [https://en.wikipedia.org/wiki/Mersenne_prime] P = 2**n -1, used for numeric hash scheme.

Added in version 3.13.

PyHASH_BITS

The exponent n of P in PyHASH_MODULUS.

Added in version 3.13.

PyHASH_MULTIPLIER

Prime multiplier used in string and various other hashes.

Added in version 3.13.

PyHASH_INF

The hash value returned for a positive infinity.

Added in version 3.13.

PyHASH_IMAG

The multiplier used for the imaginary part of a complex number.

Added in version 3.13.

type PyHash_FuncDef

Hash function definition used by PyHash_GetFuncDef().

const char *name

Hash function name (UTF-8 encoded string).

const int hash_bits

Internal size of the hash value in bits.

const int seed_bits

Size of seed input in bits.

Added in version 3.4.

PyHash_FuncDef *PyHash_GetFuncDef(void)

Get the hash function definition.

더 보기

PEP 456 [https://peps.python.org/pep-0456/] “Secure and interchangeable hash algorithm”.

Added in version 3.4.

Py_hash_t Py_HashPointer(const void *ptr)

Hash a pointer value: process the pointer value as an integer (cast it to uintptr_t internally). The pointer is not dereferenced.

The function cannot fail: it cannot return -1.

Added in version 3.13.

Py_hash_t Py_HashBuffer(const void *ptr, Py_ssize_t len)

Compute and return the hash value of a buffer of len bytes starting at address ptr. The hash is guaranteed to match that of bytes, memoryview, and other built-in objects that implement the buffer protocol.

Use this function to implement hashing for immutable objects whose tp_richcompare function compares to another object’s buffer.

len must be greater than or equal to 0.

This function always succeeds.

Added in version 3.14.

Py_hash_t PyObject_GenericHash(PyObject *obj)

Generic hashing function that is meant to be put into a type object’s tp_hash slot. Its result only depends on the object’s identity.

CPython 구현 상세: In CPython, it is equivalent to Py_HashPointer().

Added in version 3.13.

리플렉션

PyObject *PyEval_GetBuiltins(void)

Return value: Borrowed reference. Part of the Stable ABI.

버전 3.13부터 폐지됨: Use PyEval_GetFrameBuiltins() instead.

현재 실행 프레임이나 현재 실행 중인 프레임이 없으면 스레드 상태의 인터프리터의 builtins의 딕셔너리를 반환합니다.

PyObject *PyEval_GetLocals(void)

Return value: Borrowed reference. Part of the Stable ABI.

버전 3.13부터 폐지됨: Use either PyEval_GetFrameLocals() to obtain the same behaviour as calling locals() in Python code, or else call PyFrame_GetLocals() on the result of PyEval_GetFrame() to access the f_locals attribute of the currently executing frame.

Return a mapping providing access to the local variables in the current execution frame, or NULL if no frame is currently executing.

Refer to locals() for details of the mapping returned at different scopes.

As this function returns a borrowed reference, the dictionary returned for optimized scopes is cached on the frame object and will remain alive as long as the frame object does. Unlike PyEval_GetFrameLocals() and locals(), subsequent calls to this function in the same frame will update the contents of the cached dictionary to reflect changes in the state of the local variables rather than returning a new snapshot.

버전 3.13에서 변경: As part of PEP 667 [https://peps.python.org/pep-0667/], PyFrame_GetLocals(), locals(), and FrameType.f_locals no longer make use of the shared cache dictionary. Refer to the What’s New entry for additional details.

PyObject *PyEval_GetGlobals(void)

Return value: Borrowed reference. Part of the Stable ABI.

버전 3.13부터 폐지됨: Use PyEval_GetFrameGlobals() instead.

현재 실행 프레임의 전역 변수 딕셔너리를 반환하거나, 현재 실행 중인 프레임이 없으면 NULL을 반환합니다.

PyFrameObject *PyEval_GetFrame(void)

Return value: Borrowed reference. Part of the Stable ABI.

현재의 스레드 상태의 프레임을 반환합니다. 현재 실행 중의 프레임이 없으면 NULL입니다.

PyThreadState_GetFrame()도 참조하십시오.

PyObject *PyEval_GetFrameBuiltins(void)

Return value: New reference. Part of the Stable ABI since version 3.13.

현재 실행 프레임이나 현재 실행 중인 프레임이 없으면 스레드 상태의 인터프리터의 builtins의 딕셔너리를 반환합니다.

Added in version 3.13.

PyObject *PyEval_GetFrameLocals(void)

Return value: New reference. Part of the Stable ABI since version 3.13.

Return a dictionary of the local variables in the current execution frame, or NULL if no frame is currently executing. Equivalent to calling locals() in Python code.

To access f_locals on the current frame without making an independent snapshot in optimized scopes, call PyFrame_GetLocals() on the result of PyEval_GetFrame().

Added in version 3.13.

PyObject *PyEval_GetFrameGlobals(void)

Return value: New reference. Part of the Stable ABI since version 3.13.

Return a dictionary of the global variables in the current execution frame, or NULL if no frame is currently executing. Equivalent to calling globals() in Python code.

Added in version 3.13.

const char *PyEval_GetFuncName(PyObject *func)

Part of the Stable ABI.

func가 함수, 클래스 또는 인스턴스 객체면 func의 이름을 반환하고, 그렇지 않으면 func의 형의 이름을 반환합니다.

const char *PyEval_GetFuncDesc(PyObject *func)

Part of the Stable ABI.

func의 형에 따라 설명 문자열을 반환합니다. 반환 값에는 함수 및 메서드의 “()”, “ constructor”, “ instance” 및 “ object” 가 포함됩니다. PyEval_GetFuncName()의 결과와 이어붙이면 func의 설명이 됩니다.

코덱 등록소와 지원 함수

int PyCodec_Register(PyObject *search_function)

Part of the Stable ABI.

새로운 코덱 검색 함수를 등록합니다.

As side effect, this tries to load the encodings package, if not yet done, to make sure that it is always first in the list of search functions.

int PyCodec_Unregister(PyObject *search_function)

Part of the Stable ABI since version 3.10.

Unregister a codec search function and clear the registry’s cache. If the search function is not registered, do nothing. Return 0 on success. Raise an exception and return -1 on error.

Added in version 3.10.

int PyCodec_KnownEncoding(const char *encoding)

Part of the Stable ABI.

지정된 encoding에 대해 등록된 코덱이 있는지에 따라 1 이나 0을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyCodec_Encode(PyObject *object, const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

일반 코덱 기반 인코딩 API.

object는 errors로 정의된 에러 처리 방법을 사용하여 지정된 encoding에 대해 발견된 인코더 함수로 전달됩니다. 코덱에 정의된 기본 방법을 사용하기 위해 errors가 NULL 일 수 있습니다. 인코더를 찾을 수 없으면 LookupError를 발생시킵니다.

PyObject *PyCodec_Decode(PyObject *object, const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

일반 코덱 기반 디코딩 API.

object는 errors로 정의된 에러 처리 방법을 사용하여 지정된 encoding에 대해 발견된 디코더 함수로 전달됩니다. 코덱에 정의된 기본 방법을 사용하기 위해 errors가 NULL 일 수 있습니다. 인코더를 찾을 수 없으면 LookupError를 발생시킵니다.

코덱 조회 API

다음 함수에서, encoding 문자열은 모두 소문자로 변환되어 조회되므로, 이 메커니즘을 통한 인코딩 조회는 대소문자를 구분하지 않게 됩니다. 코덱이 없으면, KeyError가 설정되고 NULL이 반환됩니다.

PyObject *PyCodec_Encoder(const char *encoding)

Return value: New reference. Part of the Stable ABI.

주어진 encoding에 대한 인코더 함수를 가져옵니다.

PyObject *PyCodec_Decoder(const char *encoding)

Return value: New reference. Part of the Stable ABI.

주어진 encoding에 대한 디코더 함수를 가져옵니다.

PyObject *PyCodec_IncrementalEncoder(const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

지정된 encoding에 대한 IncrementalEncoder 객체를 가져옵니다.

PyObject *PyCodec_IncrementalDecoder(const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

지정된 encoding에 대한 IncrementalDecoder 객체를 가져옵니다.

PyObject *PyCodec_StreamReader(const char *encoding, PyObject *stream, const char *errors)

Return value: New reference. Part of the Stable ABI.

지정된 encoding에 대한 StreamReader 팩토리 함수를 가져옵니다.

PyObject *PyCodec_StreamWriter(const char *encoding, PyObject *stream, const char *errors)

Return value: New reference. Part of the Stable ABI.

지정된 encoding에 대한 StreamWriter 팩토리 함수를 가져옵니다.

유니코드 인코딩 에러 처리기용 등록소 API

int PyCodec_RegisterError(const char *name, PyObject *error)

Part of the Stable ABI.

지정된 name 으로 에러 처리 콜백 함수 error를 등록합니다. 코덱이 인코딩할 수 없는 문자/디코딩할 수 없는 바이트열을 발견하고, 인코드/디코드 함수를 호출할 때 name이 error 매개 변수로 지정되었을 때 이 콜백 함수를 호출합니다.

콜백은 하나의 인자로 UnicodeEncodeError, UnicodeDecodeError 또는 UnicodeTranslateError의 인스턴스를 받아들이는데, 문제가 되는 문자나 바이트의 시퀀스와 이들의 원본 문자열에서의 오프셋에 대한 정보를 담고 있습니다 (이 정보를 추출하는 함수는 유니코드 예외 객체를 참조하세요). 콜백은 주어진 예외를 발생시키거나, 문제가 있는 시퀀스의 대체와 원래 문자열에서 인코딩/디코딩을 다시 시작해야 하는 오프셋을 제공하는 정수를 포함하는 두 항목 튜플을 반환해야 합니다.

성공하면 0을, 에러면 -1을 반환합니다.

PyObject *PyCodec_LookupError(const char *name)

Return value: New reference. Part of the Stable ABI.

name 으로 등록된 에러 처리 콜백 함수를 찾습니다. 특수한 경우로 NULL이 전달 될 수 있는데, 이때는 “strict” 에 대한 에러 처리 콜백이 반환됩니다.

PyObject *PyCodec_StrictErrors(PyObject *exc)

Return value: Always NULL. Part of the Stable ABI.

exc를 예외로 발생시킵니다.

PyObject *PyCodec_IgnoreErrors(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

잘못된 입력을 건너뛰고, 유니코드 에러를 무시합니다.

PyObject *PyCodec_ReplaceErrors(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

유니코드 인코딩 에러를 ? 나 U+FFFD로 치환합니다.

PyObject *PyCodec_XMLCharRefReplaceErrors(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

유니코드 인코딩 에러를 XML 문자 참조로 치환합니다.

PyObject *PyCodec_BackslashReplaceErrors(PyObject *exc)

Return value: New reference. Part of the Stable ABI.

유니코드 인코딩 에러를 백 슬래시 이스케이프(\x, \u 및 \U)로 치환합니다.

PyObject *PyCodec_NameReplaceErrors(PyObject *exc)

Return value: New reference. Part of the Stable ABI since version 3.7.

유니코드 인코딩 에러를 \N{...} 이스케이프로 치환합니다.

Added in version 3.5.

PyTime C API

Added in version 3.13.

The clock C API provides access to system clocks. It is similar to the Python time module.

For C API related to the datetime module, see DateTime 객체.

Types

type PyTime_t

A timestamp or duration in nanoseconds, represented as a signed 64-bit integer.

The reference point for timestamps depends on the clock used. For example, PyTime_Time() returns timestamps relative to the UNIX epoch.

The supported range is around [-292.3 years; +292.3 years]. Using the Unix epoch (January 1st, 1970) as reference, the supported date range is around [1677-09-21; 2262-04-11]. The exact limits are exposed as constants:

PyTime_t PyTime_MIN

Minimum value of PyTime_t.

PyTime_t PyTime_MAX

Maximum value of PyTime_t.

Clock Functions

The following functions take a pointer to a PyTime_t that they set to the value of a particular clock. Details of each clock are given in the documentation of the corresponding Python function.

The functions return 0 on success, or -1 (with an exception set) on failure.

On integer overflow, they set the PyExc_OverflowError exception and set *result to the value clamped to the [PyTime_MIN; PyTime_MAX] range. (On current systems, integer overflows are likely caused by misconfigured system time.)

As any other C API (unless otherwise specified), the functions must be called with the GIL held.

int PyTime_Monotonic(PyTime_t *result)

Read the monotonic clock. See time.monotonic() for important details on this clock.

int PyTime_PerfCounter(PyTime_t *result)

Read the performance counter. See time.perf_counter() for important details on this clock.

int PyTime_Time(PyTime_t *result)

Read the “wall clock” time. See time.time() for details important on this clock.

Raw Clock Functions

Similar to clock functions, but don’t set an exception on error and don’t require the caller to hold the GIL.

On success, the functions return 0.

On failure, they set *result to 0 and return -1, without setting an exception. To get the cause of the error, acquire the GIL and call the regular (non-Raw) function. Note that the regular function may succeed after the Raw one failed.

int PyTime_MonotonicRaw(PyTime_t *result)

Similar to PyTime_Monotonic(), but don’t set an exception on error and don’t require holding the GIL.

int PyTime_PerfCounterRaw(PyTime_t *result)

Similar to PyTime_PerfCounter(), but don’t set an exception on error and don’t require holding the GIL.

int PyTime_TimeRaw(PyTime_t *result)

Similar to PyTime_Time(), but don’t set an exception on error and don’t require holding the GIL.

Conversion functions

double PyTime_AsSecondsDouble(PyTime_t t)

Convert a timestamp to a number of seconds as a C double.

The function cannot fail, but note that double has limited accuracy for large values.

Support for Perf Maps

On supported platforms (as of this writing, only Linux), the runtime can take advantage of perf map files to make Python functions visible to an external profiling tool (such as perf [https://perf.wiki.kernel.org/index.php/Main_Page]). A running process may create a file in the /tmp directory, which contains entries that can map a section of executable code to a name. This interface is described in the documentation of the Linux Perf tool [https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/Documentation/jit-interface.txt].

In Python, these helper APIs can be used by libraries and features that rely on generating machine code on the fly.

Note that holding the Global Interpreter Lock (GIL) is not required for these APIs.

int PyUnstable_PerfMapState_Init(void)

This is Unstable API. It may change without warning in minor releases.

Open the /tmp/perf-$pid.map file, unless it’s already opened, and create a lock to ensure thread-safe writes to the file (provided the writes are done through PyUnstable_WritePerfMapEntry()). Normally, there’s no need to call this explicitly; just use PyUnstable_WritePerfMapEntry() and it will initialize the state on first call.

Returns 0 on success, -1 on failure to create/open the perf map file, or -2 on failure to create a lock. Check errno for more information about the cause of a failure.

int PyUnstable_WritePerfMapEntry(const void *code_addr, unsigned int code_size, const char *entry_name)

This is Unstable API. It may change without warning in minor releases.

Write one single entry to the /tmp/perf-$pid.map file. This function is thread safe. Here is what an example entry looks like:

# address      size  name
7f3529fcf759 b     py::bar:/run/t.py

Will call PyUnstable_PerfMapState_Init() before writing the entry, if the perf map file is not already opened. Returns 0 on success, or the same error codes as PyUnstable_PerfMapState_Init() on failure.

void PyUnstable_PerfMapState_Fini(void)

This is Unstable API. It may change without warning in minor releases.

Close the perf map file opened by PyUnstable_PerfMapState_Init(). This is called by the runtime itself during interpreter shut-down. In general, there shouldn’t be a reason to explicitly call this, except to handle specific scenarios such as forking.

추상 객체 계층

이 장의 함수는 객체의 형과 무관하게, 혹은 광범위한 종류의 객체 형의 (예를 들어, 모든 숫자 형 또는 모든 시퀀스 형) 파이썬 객체와 상호 작용합니다. 적용되지 않는 객체 형에 사용되면, 파이썬 예외가 발생합니다.

PyList_New()로 만들었지만, 항목이 아직 NULL이 아닌 값으로 설정되지 않은 리스트 객체와 같이, 제대로 초기화되지 않은 객체에 대해서는 이 함수를 사용할 수 없습니다.

객체 프로토콜

호출 프로토콜

tp_call 프로토콜

벡터콜(Vectorcall) 프로토콜

재귀 제어

벡터콜 지원 API

객체 호출 API

호출 지원 API

숫자 프로토콜

시퀀스 프로토콜

매핑 프로토콜

이터레이터 프로토콜

버퍼 프로토콜

버퍼 구조체

버퍼 요청 유형

요청 독립적 필드

readonly, format

shape, strides, suboffsets

연속성 요청

복합 요청

복잡한 배열

NumPy-스타일: shape과 strides

PIL-스타일: shape, strides 및 suboffsets

버퍼 관련 함수

객체 프로토콜

PyObject *Py_GetConstant(unsigned int constant_id)

Part of the Stable ABI since version 3.13.

Get a strong reference to a constant.

Set an exception and return NULL if constant_id is invalid.

constant_id must be one of these constant identifiers:

Constant Identifier

Value

Returned object

Py_CONSTANT_NONE

0

None

Py_CONSTANT_FALSE

1

False

Py_CONSTANT_TRUE

2

True

Py_CONSTANT_ELLIPSIS

3

Ellipsis

Py_CONSTANT_NOT_IMPLEMENTED

4

NotImplemented

Py_CONSTANT_ZERO

5

0

Py_CONSTANT_ONE

6

1

Py_CONSTANT_EMPTY_STR

7

''

Py_CONSTANT_EMPTY_BYTES

8

b''

Py_CONSTANT_EMPTY_TUPLE

9

()

Numeric values are only given for projects which cannot use the constant identifiers.

Added in version 3.13.

CPython 구현 상세: In CPython, all of these constants are immortal.

PyObject *Py_GetConstantBorrowed(unsigned int constant_id)

Part of the Stable ABI since version 3.13.

Similar to Py_GetConstant(), but return a borrowed reference.

This function is primarily intended for backwards compatibility: using Py_GetConstant() is recommended for new code.

The reference is borrowed from the interpreter, and is valid until the interpreter finalization.

Added in version 3.13.

PyObject *Py_NotImplemented

지정된 형 조합에 대해 연산이 구현되지 않았음을 알리는 데 사용되는 NotImplemented 싱글톤.

Py_RETURN_NOTIMPLEMENTED

Properly handle returning Py_NotImplemented from within a C function (that is, create a new strong reference to NotImplemented and return it).

Py_PRINT_RAW

Flag to be used with multiple functions that print the object (like PyObject_Print() and PyFile_WriteObject()). If passed, these function would use the str() of the object instead of the repr().

int PyObject_Print(PyObject *o, FILE *fp, int flags)

Print an object o, on file fp. Returns -1 on error. The flags argument is used to enable certain printing options. The only option currently supported is Py_PRINT_RAW; if given, the str() of the object is written instead of the repr().

int PyObject_HasAttrWithError(PyObject *o, const char *attr_name)

Part of the Stable ABI since version 3.13.

Returns 1 if o has the attribute attr_name, and 0 otherwise. This is equivalent to the Python expression hasattr(o, attr_name). On failure, return -1.

Added in version 3.13.

int PyObject_HasAttrStringWithError(PyObject *o, const char *attr_name)

Part of the Stable ABI since version 3.13.

This is the same as PyObject_HasAttrWithError(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

int PyObject_HasAttr(PyObject *o, PyObject *attr_name)

Part of the Stable ABI.

Returns 1 if o has the attribute attr_name, and 0 otherwise. This function always succeeds.

참고

Exceptions that occur when this calls __getattr__() and __getattribute__() methods are silently ignored. For proper error handling, use PyObject_HasAttrWithError(), PyObject_GetOptionalAttr() or PyObject_GetAttr() instead.

int PyObject_HasAttrString(PyObject *o, const char *attr_name)

Part of the Stable ABI.

This is the same as PyObject_HasAttr(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

참고

Exceptions that occur when this calls __getattr__() and __getattribute__() methods or while creating the temporary str object are silently ignored. For proper error handling, use PyObject_HasAttrStringWithError(), PyObject_GetOptionalAttrString() or PyObject_GetAttrString() instead.

PyObject *PyObject_GetAttr(PyObject *o, PyObject *attr_name)

Return value: New reference. Part of the Stable ABI.

객체 o에서 attr_name이라는 이름의 어트리뷰트를 가져옵니다. 성공하면 어트리뷰트 값을, 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 o.attr_name과 동등합니다.

If the missing attribute should not be treated as a failure, you can use PyObject_GetOptionalAttr() instead.

PyObject *PyObject_GetAttrString(PyObject *o, const char *attr_name)

Return value: New reference. Part of the Stable ABI.

This is the same as PyObject_GetAttr(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

If the missing attribute should not be treated as a failure, you can use PyObject_GetOptionalAttrString() instead.

int PyObject_GetOptionalAttr(PyObject *obj, PyObject *attr_name, PyObject **result);

Part of the Stable ABI since version 3.13.

Variant of PyObject_GetAttr() which doesn’t raise AttributeError if the attribute is not found.

If the attribute is found, return 1 and set *result to a new strong reference to the attribute. If the attribute is not found, return 0 and set *result to NULL; the AttributeError is silenced. If an error other than AttributeError is raised, return -1 and set *result to NULL.

Added in version 3.13.

int PyObject_GetOptionalAttrString(PyObject *obj, const char *attr_name, PyObject **result);

Part of the Stable ABI since version 3.13.

This is the same as PyObject_GetOptionalAttr(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

PyObject *PyObject_GenericGetAttr(PyObject *o, PyObject *name)

Return value: New reference. Part of the Stable ABI.

형 객체의 tp_getattro 슬롯에 배치되는 일반 어트리뷰트 게터(getter) 함수. 객체의 (있다면) __dict__에 있는 어트리뷰트뿐만 아니라 객체의 MRO에 있는 클래스의 딕셔너리에 있는 디스크립터를 찾습니다. 디스크립터 구현하기에 요약된 것처럼, 데이터 디스크립터는 인스턴스 어트리뷰트보다 우선하지만, 비 데이터 디스크립터는 그렇지 않습니다. 그렇지 않으면, AttributeError가 발생합니다.

int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)

Part of the Stable ABI.

객체 o에 대해, attr_name이라는 이름의 어트리뷰트 값을 v 값으로 설정합니다. 실패 시 예외를 발생시키고 -1을 반환합니다. 성공하면 0을 반환합니다. 이것은 파이썬 문장 o.attr_name = v와 동등합니다.

If v is NULL, the attribute is deleted. This behaviour is deprecated in favour of using PyObject_DelAttr(), but there are currently no plans to remove it.

int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)

Part of the Stable ABI.

This is the same as PyObject_SetAttr(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

If v is NULL, the attribute is deleted, but this feature is deprecated in favour of using PyObject_DelAttrString().

The number of different attribute names passed to this function should be kept small, usually by using a statically allocated string as attr_name. For attribute names that aren’t known at compile time, prefer calling PyUnicode_FromString() and PyObject_SetAttr() directly. For more details, see PyUnicode_InternFromString(), which may be used internally to create a key object.

int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)

Part of the Stable ABI.

형 객체의 tp_setattro 슬롯에 배치되는 일반 어트리뷰트 세터(setter)와 딜리터(deleter) 함수. 객체의 MRO에 있는 클래스의 딕셔너리에서 데이터 디스크립터를 찾고, 발견되면 인스턴스 딕셔너리에 있는 어트리뷰트를 설정하거나 삭제하는 것보다 우선합니다. 그렇지 않으면, 객체의 (있다면) __dict__에서 어트리뷰트가 설정되거나 삭제됩니다. 성공하면 0이 반환되고, 그렇지 않으면 AttributeError가 발생하고 -1이 반환됩니다.

int PyObject_DelAttr(PyObject *o, PyObject *attr_name)

Part of the Stable ABI since version 3.13.

객체 o에 대해, attr_name이라는 이름의 어트리뷰트를 삭제합니다. 실패 시 -1을 반환합니다. 이것은 파이썬 문장 del o.attr_name과 동등합니다.

int PyObject_DelAttrString(PyObject *o, const char *attr_name)

Part of the Stable ABI since version 3.13.

This is the same as PyObject_DelAttr(), but attr_name is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

The number of different attribute names passed to this function should be kept small, usually by using a statically allocated string as attr_name. For attribute names that aren’t known at compile time, prefer calling PyUnicode_FromString() and PyObject_DelAttr() directly. For more details, see PyUnicode_InternFromString(), which may be used internally to create a key object for lookup.

PyObject *PyObject_GenericGetDict(PyObject *o, void *context)

Return value: New reference. Part of the Stable ABI since version 3.10.

__dict__ 디스크립터의 게터(getter)를 위한 일반적인 구현. 필요하면 딕셔너리를 만듭니다.

This function may also be called to get the __dict__ of the object o. Pass NULL for context when calling it. Since this function may need to allocate memory for the dictionary, it may be more efficient to call PyObject_GetAttr() when accessing an attribute on the object.

On failure, returns NULL with an exception set.

Added in version 3.3.

int PyObject_GenericSetDict(PyObject *o, PyObject *value, void *context)

Part of the Stable ABI since version 3.7.

__dict__ 디스크립터의 세터(setter)를 위한 일반적인 구현. 이 구현은 딕셔너리 삭제를 허락하지 않습니다.

Added in version 3.3.

PyObject **_PyObject_GetDictPtr(PyObject *obj)

Return a pointer to __dict__ of the object obj. If there is no __dict__, return NULL without setting an exception.

This function may need to allocate memory for the dictionary, so it may be more efficient to call PyObject_GetAttr() when accessing an attribute on the object.

PyObject *PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)

Return value: New reference. Part of the Stable ABI.

Compare the values of o1 and o2 using the operation specified by opid, which must be one of Py_LT, Py_LE, Py_EQ, Py_NE, Py_GT, or Py_GE, corresponding to <, <=, ==, !=, >, or >= respectively. This is the equivalent of the Python expression o1 op o2, where op is the operator corresponding to opid. Returns the value of the comparison on success, or NULL on failure.

int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)

Part of the Stable ABI.

Compare the values of o1 and o2 using the operation specified by opid, like PyObject_RichCompare(), but returns -1 on error, 0 if the result is false, 1 otherwise.

참고

If o1 and o2 are the same object, PyObject_RichCompareBool() will always return 1 for Py_EQ and 0 for Py_NE.

PyObject *PyObject_Format(PyObject *obj, PyObject *format_spec)

Part of the Stable ABI.

Format obj using format_spec. This is equivalent to the Python expression format(obj, format_spec).

format_spec may be NULL. In this case the call is equivalent to format(obj). Returns the formatted string on success, NULL on failure.

PyObject *PyObject_Repr(PyObject *o)

Return value: New reference. Part of the Stable ABI.

객체 o의 문자열 표현을 계산합니다. 성공하면 문자열 표현을, 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 repr(o)와 동등합니다. repr() 내장 함수에 의해 호출됩니다.

버전 3.4에서 변경: 이 함수에는 이제 디버그 어서션이 포함되어 있어 활성 예외를 조용히 버리지 않도록 합니다.

PyObject *PyObject_ASCII(PyObject *o)

Return value: New reference. Part of the Stable ABI.

PyObject_Repr()처럼, 객체 o의 문자열 표현을 계산하지만, \x, \u 또는 \U 이스케이프를 사용하여 PyObject_Repr()이 반환한 문자열에서 비 ASCII 문자를 이스케이프 합니다. 이것은 파이썬 2에서 PyObject_Repr()에 의해 반환된 것과 유사한 문자열을 생성합니다. ascii() 내장 함수에 의해 호출됩니다.

PyObject *PyObject_Str(PyObject *o)

Return value: New reference. Part of the Stable ABI.

객체 o의 문자열 표현을 계산합니다. 성공 시 문자열 표현을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 str(o)와 동등합니다. str() 내장 함수에 의해, 따라서 print() 함수에 의해서도 호출됩니다.

버전 3.4에서 변경: 이 함수에는 이제 디버그 어서션이 포함되어 있어 활성 예외를 조용히 버리지 않도록 합니다.

PyObject *PyObject_Bytes(PyObject *o)

Return value: New reference. Part of the Stable ABI.

객체 o의 바이트열 표현을 계산합니다. 실패하면 NULL을, 성공하면 바이트열 객체를 반환됩니다. 이는 o가 정수가 아닐 때 파이썬 표현식 bytes(o)와 동등합니다. bytes(o)와 달리, o가 정수이면 0으로 초기화된 바이트열 객체 대신 TypeError가 발생합니다.

int PyObject_IsSubclass(PyObject *derived, PyObject *cls)

Part of the Stable ABI.

클래스 derived가 클래스 cls와 동일하거나 cls에서 파생되었으면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 에러가 발생하면 -1을 반환합니다.

cls가 튜플이면, cls의 모든 항목에 대해 검사가 수행됩니다. 적어도 하나의 검사에서 1을 반환하면 결과는 1이 되고, 그렇지 않으면 0이 됩니다.

If cls has a __subclasscheck__() method, it will be called to determine the subclass status as described in PEP 3119 [https://peps.python.org/pep-3119/]. Otherwise, derived is a subclass of cls if it is a direct or indirect subclass, i.e. contained in cls.__mro__.

Normally only class objects, i.e. instances of type or a derived class, are considered classes. However, objects can override this by having a __bases__ attribute (which must be a tuple of base classes).

int PyObject_IsInstance(PyObject *inst, PyObject *cls)

Part of the Stable ABI.

inst가 cls 클래스나 cls의 서브 클래스의 인스턴스이면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 에러가 발생하면 -1을 반환하고 예외를 설정합니다.

cls가 튜플이면, cls의 모든 항목에 대해 검사가 수행됩니다. 적어도 하나의 검사에서 1을 반환하면 결과는 1이 되고, 그렇지 않으면 0이 됩니다.

If cls has a __instancecheck__() method, it will be called to determine the subclass status as described in PEP 3119 [https://peps.python.org/pep-3119/]. Otherwise, inst is an instance of cls if its class is a subclass of cls.

An instance inst can override what is considered its class by having a __class__ attribute.

An object cls can override if it is considered a class, and what its base classes are, by having a __bases__ attribute (which must be a tuple of base classes).

Py_hash_t PyObject_Hash(PyObject *o)

Part of the Stable ABI.

객체 o의 해시값을 계산하고 반환합니다. 실패하면 -1을 반환합니다. 이것은 파이썬 표현식 hash(o)와 동등합니다.

버전 3.2에서 변경: The return type is now Py_hash_t. This is a signed integer the same size as Py_ssize_t.

Py_hash_t PyObject_HashNotImplemented(PyObject *o)

Part of the Stable ABI.

Set a TypeError indicating that type(o) is not hashable and return -1. This function receives special treatment when stored in a tp_hash slot, allowing a type to explicitly indicate to the interpreter that it is not hashable.

int PyObject_IsTrue(PyObject *o)

Part of the Stable ABI.

객체 o를 참으로 간주하면 1을, 그렇지 않으면 0을 반환합니다. 이것은 파이썬 표현식 not not o와 동등합니다. 실패하면 -1을 반환합니다.

int PyObject_Not(PyObject *o)

Part of the Stable ABI.

객체 o를 참으로 간주하면 0을, 그렇지 않으면 1을 반환합니다. 이것은 파이썬 표현식 not o와 동등합니다. 실패하면 -1을 반환합니다.

PyObject *PyObject_Type(PyObject *o)

Return value: New reference. Part of the Stable ABI.

When o is non-NULL, returns a type object corresponding to the object type of object o. On failure, raises SystemError and returns NULL. This is equivalent to the Python expression type(o). This function creates a new strong reference to the return value. There’s really no reason to use this function instead of the Py_TYPE() function, which returns a pointer of type PyTypeObject*, except when a new strong reference is needed.

int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)

Return non-zero if the object o is of type type or a subtype of type, and 0 otherwise. Both parameters must be non-NULL.

Py_ssize_t PyObject_Size(PyObject *o)

Py_ssize_t PyObject_Length(PyObject *o)

Part of the Stable ABI.

객체 o의 길이를 반환합니다. 객체 o가 시퀀스와 매핑 프로토콜을 제공하면, 시퀀스 길이가 반환됩니다. 에러가 발생하면 -1이 반환됩니다. 이것은 파이썬 표현식 len(o)와 동등합니다.

Py_ssize_t PyObject_LengthHint(PyObject *o, Py_ssize_t defaultvalue)

Return an estimated length for the object o. First try to return its actual length, then an estimate using __length_hint__(), and finally return the default value. On error return -1. This is the equivalent to the Python expression operator.length_hint(o, defaultvalue).

Added in version 3.4.

PyObject *PyObject_GetItem(PyObject *o, PyObject *key)

Return value: New reference. Part of the Stable ABI.

객체 key에 해당하는 o의 요소를 반환하거나 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o[key]와 동등합니다.

int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)

Part of the Stable ABI.

객체 key를 값 v에 매핑합니다. 실패 시 예외를 발생시키고 -1을 반환합니다; 성공하면 0을 반환합니다. 이것은 파이썬 문장 o[key] = v와 동등합니다. 이 함수는 v에 대한 참조를 훔치지 않습니다.

int PyObject_DelItem(PyObject *o, PyObject *key)

Part of the Stable ABI.

객체 o에서 객체 key에 대한 매핑을 제거합니다. 실패하면 -1을 반환합니다. 이것은 파이썬 문장 del o[key]와 동등합니다.

PyObject *PyObject_Dir(PyObject *o)

Return value: New reference. Part of the Stable ABI.

이것은 파이썬 표현식 dir(o)와 동등하며, 객체 인자에 적합한 문자열의 (비어있을 수 있는) 리스트를 반환하거나, 에러가 있으면 NULL을 반환합니다. 인자가 NULL이면, 파이썬 dir()과 비슷하며, 현재 지역(locals)의 이름들을 반환합니다; 이 경우, 실행 프레임이 활성화되어 있지 않으면 NULL이 반환되지만 PyErr_Occurred()는 거짓을 반환합니다.

PyObject *PyObject_GetIter(PyObject *o)

Return value: New reference. Part of the Stable ABI.

이것은 파이썬 표현식 iter(o)와 동등합니다. 객체 인자에 대한 새로운 이터레이터를 반환하거나, 객체가 이미 이터레이터이면 객체 자체를 반환합니다. 객체를 이터레이트 할 수 없으면 TypeError를 발생시키고 NULL을 반환합니다.

PyObject *PyObject_GetAIter(PyObject *o)

Return value: New reference. Part of the Stable ABI since version 3.10.

This is the equivalent to the Python expression aiter(o). Takes an AsyncIterable object and returns an AsyncIterator for it. This is typically a new iterator but if the argument is an AsyncIterator, this returns itself. Raises TypeError and returns NULL if the object cannot be iterated.

Added in version 3.10.

void *PyObject_GetTypeData(PyObject *o, PyTypeObject *cls)

Part of the Stable ABI since version 3.12.

Get a pointer to subclass-specific data reserved for cls.

The object o must be an instance of cls, and cls must have been created using negative PyType_Spec.basicsize. Python does not check this.

On error, set an exception and return NULL.

Added in version 3.12.

Py_ssize_t PyType_GetTypeDataSize(PyTypeObject *cls)

Part of the Stable ABI since version 3.12.

Return the size of the instance memory space reserved for cls, i.e. the size of the memory PyObject_GetTypeData() returns.

This may be larger than requested using -PyType_Spec.basicsize; it is safe to use this larger size (e.g. with memset()).

The type cls must have been created using negative PyType_Spec.basicsize. Python does not check this.

On error, set an exception and return a negative value.

Added in version 3.12.

void *PyObject_GetItemData(PyObject *o)

Get a pointer to per-item data for a class with Py_TPFLAGS_ITEMS_AT_END.

On error, set an exception and return NULL. TypeError is raised if o does not have Py_TPFLAGS_ITEMS_AT_END set.

Added in version 3.12.

int PyObject_VisitManagedDict(PyObject *obj, visitproc visit, void *arg)

Visit the managed dictionary of obj.

This function must only be called in a traverse function of the type which has the Py_TPFLAGS_MANAGED_DICT flag set.

Added in version 3.13.

void PyObject_ClearManagedDict(PyObject *obj)

Clear the managed dictionary of obj.

This function must only be called in a traverse function of the type which has the Py_TPFLAGS_MANAGED_DICT flag set.

Added in version 3.13.

int PyUnstable_Object_EnableDeferredRefcount(PyObject *obj)

This is Unstable API. It may change without warning in minor releases.

Enable deferred reference counting [https://peps.python.org/pep-0703/#deferred-reference-counting] on obj, if supported by the runtime. In the free-threaded build, this allows the interpreter to avoid reference count adjustments to obj, which may improve multi-threaded performance. The tradeoff is that obj will only be deallocated by the tracing garbage collector.

This function returns 1 if deferred reference counting is enabled on obj (including when it was enabled before the call), and 0 if deferred reference counting is not supported or if the hint was ignored by the runtime. This function is thread-safe, and cannot fail.

This function does nothing on builds with the GIL enabled, which do not support deferred reference counting. This also does nothing if obj is not an object tracked by the garbage collector (see gc.is_tracked() and PyObject_GC_IsTracked()).

This function is intended to be used soon after obj is created, by the code that creates it.

Added in version 3.14.

호출 프로토콜

CPython은 두 가지 호출 프로토콜을 지원합니다: tp_call과 벡터콜(vectorcall).

tp_call 프로토콜

tp_call을 설정하는 클래스의 인스턴스는 콜러블입니다. 슬롯의 서명은 다음과 같습니다:

PyObject *tp_call(PyObject *callable, PyObject *args, PyObject *kwargs);

파이썬 코드의 callable(*args, **kwargs) 와 유사하게, 위치 인자를 위한 튜플과 키워드 인자를 위한 딕셔너리를 사용하여 호출합니다. args는 NULL이 아니어야 합니다 (인자가 없으면 빈 튜플을 사용하십시오). 하지만 키워드 인자가 없으면 kwargs는 NULL일 수 있습니다.

이 규칙은 tp_call에서만 사용되는 것이 아닙니다: tp_new와 tp_init도 인자를 이런 식으로 전달합니다.

To call an object, use PyObject_Call() or another call API.

벡터콜(Vectorcall) 프로토콜

Added in version 3.9.

벡터콜 프로토콜은 PEP 590 [https://peps.python.org/pep-0590/]에서 호출 효율을 높이기 위한 추가 프로토콜로 도입되었습니다.

경험 규칙으로, CPython은 콜러블이 지원하면 내부 호출에 대해 벡터콜을 선호합니다. 그러나 이것은 엄격한 규칙이 아닙니다. 또한, 일부 제삼자 확장은 (PyObject_call()을 사용하지 않고) tp_call을 직접 사용합니다. 따라서, 벡터콜을 지원하는 클래스도 tp_call을 구현해야 합니다. 또한, 어떤 프로토콜을 사용하는지와 관계없이 콜러블은 동일하게 작동해야 합니다. 이를 위해 권장되는 방법은 tp_call을 PyVectorcall_Call()로 설정하는 것입니다. 이것이 반복을 처리합니다:

경고

벡터콜을 지원하는 클래스도 같은 의미가 있도록 tp_call을 반드시 구현해야 합니다.

버전 3.12에서 변경: The Py_TPFLAGS_HAVE_VECTORCALL flag is now removed from a class when the class’s __call__() method is reassigned. (This internally sets tp_call only, and thus may make it behave differently than the vectorcall function.) In earlier Python versions, vectorcall should only be used with immutable or static types.

tp_call보다 느려진다면 클래스는 벡터콜을 구현해서는 안 됩니다. 예를 들어, 피호출자가 어차피 인자를 인자 튜플과 kwargs 딕셔너리로 변환해야 하면, 벡터콜을 구현할 이유가 없습니다.

Classes can implement the vectorcall protocol by enabling the Py_TPFLAGS_HAVE_VECTORCALL flag and setting tp_vectorcall_offset to the offset inside the object structure where a vectorcallfunc appears. This is a pointer to a function with the following signature:

typedef PyObject *(*vectorcallfunc)(PyObject *callable, PyObject *const *args, size_t nargsf, PyObject *kwnames)

Part of the Stable ABI since version 3.12.

callable은 호출되는 객체입니다.

args는 위치 인자와 그 뒤를 따르는 키워드 인자의 값으로 구성된 C 배열입니다.

인자가 없으면 NULL일 수 있습니다.

nargsf는 위치 인자의 수에

PY_VECTORCALL_ARGUMENTS_OFFSET flag. To get the actual number of positional arguments from nargsf, use PyVectorcall_NARGS().

kwnames는 키워드 인자의 이름을 포함하는 튜플입니다;

다시 말해, kwargs 딕셔너리의 키. 이 이름들은 문자열(str이나 서브 클래스의 인스턴스)이어야하며 고유해야 합니다. 키워드 인자가 없으면, kwnames는 대신 NULL일 수 있습니다.

PY_VECTORCALL_ARGUMENTS_OFFSET

Part of the Stable ABI since version 3.12.

이 플래그가 벡터콜 nargsf 인자에 설정되면, 피호출자는 일시적으로 args[-1]을 변경할 수 있습니다. 즉, args는 할당된 벡터에서 인자 1(0이 아닙니다)을 가리킵니다. 피호출자는 반환하기 전에 args[-1] 값을 복원해야 합니다.

PyObject_VectorcallMethod() 의 경우, 이 플래그는 대신 args[0]이 변경될 수 있음을 의미합니다.

Whenever they can do so cheaply (without additional allocation), callers are encouraged to use PY_VECTORCALL_ARGUMENTS_OFFSET. Doing so will allow callables such as bound methods to make their onward calls (which include a prepended self argument) very efficiently.

Added in version 3.8.

벡터콜을 구현하는 객체를 호출하려면, 다른 콜러블과 마찬가지로 호출 API 함수를 사용하십시오. PyObject_Vectorcall()은 일반적으로 가장 효율적입니다.

재귀 제어

tp_call을 사용할 때, 피호출자는 재귀에 대해 걱정할 필요가 없습니다: CPython은 tp_call을 사용하여 호출한 경우 Py_EnterRecursiveCall() 과 Py_LeaveRecursiveCall() 을 사용합니다.

효율성을 위해, 벡터콜을 사용하여 호출한 경우에는 그렇지 않습니다: 피호출자는 필요하면 Py_EnterRecursiveCall 과 Py_LeaveRecursiveCall 을 사용해야 합니다.

벡터콜 지원 API

Py_ssize_t PyVectorcall_NARGS(size_t nargsf)

Part of the Stable ABI since version 3.12.

벡터콜 nargsf 인자가 주어지면, 실제 인자 수를 반환합니다. 현재 다음과 동등합니다:

(Py_ssize_t)(nargsf & ~PY_VECTORCALL_ARGUMENTS_OFFSET)

그러나, 향후 확장을 위해 PyVectorcall_NARGS 함수를 사용해야 합니다.

Added in version 3.8.

vectorcallfunc PyVectorcall_Function(PyObject *op)

op가 벡터콜 프로토콜을 지원하지 않으면 (형이 지원하지 않거나 인스턴스가 지원하지 않기 때문에), NULL을 반환합니다. 그렇지 않으면, op에 저장된 벡터콜 함수 포인터를 반환합니다. 이 함수는 예외를 발생시키지 않습니다.

이것은 op가 벡터콜을 지원하는지를 확인하는 데 주로 유용하며, PyVectorcall_Function(op) != NULL을 확인하여 수행 할 수 있습니다.

Added in version 3.9.

PyObject *PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *dict)

Part of the Stable ABI since version 3.12.

튜플과 딕셔너리에 각각 주어진 위치와 키워드 인자로 callable의 vectorcallfunc 를 호출합니다.

This is a specialized function, intended to be put in the tp_call slot or be used in an implementation of tp_call. It does not check the Py_TPFLAGS_HAVE_VECTORCALL flag and it does not fall back to tp_call.

Added in version 3.8.

객체 호출 API

Various functions are available for calling a Python object. Each converts its arguments to a convention supported by the called object – either tp_call or vectorcall. In order to do as little conversion as possible, pick one that best fits the format of data you have available.

다음 표는 사용 가능한 함수를 요약한 것입니다; 자세한 내용은 개별 설명서를 참조하십시오.

함수

콜러블

args

kwargs

PyObject_Call()

PyObject *

튜플

딕셔너리/NULL

PyObject_CallNoArgs()

PyObject *

—

—

PyObject_CallOneArg()

PyObject *

1 객체

—

PyObject_CallObject()

PyObject *

튜플/NULL

—

PyObject_CallFunction()

PyObject *

포맷(format)

—

PyObject_CallMethod()

obj + char*

포맷(format)

—

PyObject_CallFunctionObjArgs()

PyObject *

가변(variadic)

—

PyObject_CallMethodObjArgs()

obj + name

가변(variadic)

—

PyObject_CallMethodNoArgs()

obj + name

—

—

PyObject_CallMethodOneArg()

obj + name

1 객체

—

PyObject_Vectorcall()

PyObject *

벡터콜

벡터콜

PyObject_VectorcallDict()

PyObject *

벡터콜

딕셔너리/NULL

PyObject_VectorcallMethod()

arg + name

벡터콜

벡터콜

PyObject *PyObject_Call(PyObject *callable, PyObject *args, PyObject *kwargs)

Return value: New reference. Part of the Stable ABI.

튜플 args로 주어진 인자와 딕셔너리 kwargs로 주어진 이름있는 인자로 콜러블 파이썬 객체 callable을 호출합니다.

args는 NULL이 아니어야 합니다ㅣ 인자가 필요 없으면 빈 튜플을 사용하십시오. 이름있는 인자가 필요하지 않으면, kwargs는 NULL일 수 있습니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

이것은 다음 파이썬 표현식과 동등합니다: callable(*args, **kwargs).

PyObject *PyObject_CallNoArgs(PyObject *callable)

Return value: New reference. Part of the Stable ABI since version 3.10.

인자 없이 콜러블 파이썬 객체 callable을 호출합니다. 인자 없이 콜러블 파이썬 객체를 호출하는 가장 효율적인 방법입니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyObject_CallOneArg(PyObject *callable, PyObject *arg)

Return value: New reference.

정확히 1개의 위치 인자 arg로 키워드 인자 없이 콜러블 파이썬 객체 callable을 호출합니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyObject_CallObject(PyObject *callable, PyObject *args)

Return value: New reference. Part of the Stable ABI.

튜플 args에 의해 주어진 인자로 콜러블 파이썬 객체 callable을 호출합니다. 인자가 필요하지 않으면 args는 NULL일 수 있습니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

이것은 다음 파이썬 표현식과 동등합니다: callable(*args).

PyObject *PyObject_CallFunction(PyObject *callable, const char *format, ...)

Return value: New reference. Part of the Stable ABI.

가변 개수의 C 인자로 콜러블 파이썬 객체 callable을 호출합니다. C 인자는 Py_BuildValue() 스타일 포맷 문자열을 사용하여 기술됩니다. format은 NULL일 수 있으며, 인자가 제공되지 않음을 나타냅니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

이것은 다음 파이썬 표현식과 동등합니다: callable(*args).

Note that if you only pass PyObject* args, PyObject_CallFunctionObjArgs() is a faster alternative.

버전 3.4에서 변경: format의 형이 char *에서 변경되었습니다.

PyObject *PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)

Return value: New reference. Part of the Stable ABI.

가변 개수의 C 인자를 사용하여 객체 obj의 name이라는 이름의 메서드를 호출합니다. C 인자는 튜플을 생성해야 하는 Py_BuildValue() 포맷 문자열로 기술됩니다.

format은 NULL일 수 있으며, 인자가 제공되지 않음을 나타냅니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

이것은 다음 파이썬 표현식과 동등합니다: obj.name(arg1, arg2, ...).

Note that if you only pass PyObject* args, PyObject_CallMethodObjArgs() is a faster alternative.

버전 3.4에서 변경: name과 format의 형이 char *에서 변경되었습니다.

PyObject *PyObject_CallFunctionObjArgs(PyObject *callable, ...)

Return value: New reference. Part of the Stable ABI.

Call a callable Python object callable, with a variable number of PyObject* arguments. The arguments are provided as a variable number of parameters followed by NULL.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

이것은 다음 파이썬 표현식과 동등합니다: callable(arg1, arg2, ...).

PyObject *PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)

Return value: New reference. Part of the Stable ABI.

Call a method of the Python object obj, where the name of the method is given as a Python string object in name. It is called with a variable number of PyObject* arguments. The arguments are provided as a variable number of parameters followed by NULL.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

PyObject *PyObject_CallMethodNoArgs(PyObject *obj, PyObject *name)

인자 없이 파이썬 객체 obj의 메서드를 호출합니다. 여기서 메서드 이름은 name에서 파이썬 문자열 객체로 제공됩니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyObject_CallMethodOneArg(PyObject *obj, PyObject *name, PyObject *arg)

단일 위치 인자 arg로 파이썬 객체 obj의 메서드를 호출합니다. 여기서 메서드 이름은 name에서 파이썬 문자열 객체로 제공됩니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyObject_Vectorcall(PyObject *callable, PyObject *const *args, size_t nargsf, PyObject *kwnames)

Part of the Stable ABI since version 3.12.

콜러블 파이썬 객체 callable을 호출합니다. 인자는 vectorcallfunc 와 같습니다. callable이 벡터콜을 지원하면, callable에 저장된 벡터콜 함수를 직접 호출합니다.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyObject_VectorcallDict(PyObject *callable, PyObject *const *args, size_t nargsf, PyObject *kwdict)

위치 인자가 벡터콜 프로토콜과 정확히 일치하지만 딕셔너리 kwdict로 전달된 키워드 인자로 callable을 호출합니다. args 배열은 위치 인자만 포함합니다.

내부적으로 사용되는 프로토콜과 관계없이, 인자를 변환해야 합니다. 따라서, 이 함수는 호출자에게 이미 키워드 인자로 사용할 준비가 된 딕셔너리가 있지만, 위치 인자에 대한 튜플이 없을 때만 사용해야 합니다.

Added in version 3.9.

PyObject *PyObject_VectorcallMethod(PyObject *name, PyObject *const *args, size_t nargsf, PyObject *kwnames)

Part of the Stable ABI since version 3.12.

Call a method using the vectorcall calling convention. The name of the method is given as a Python string name. The object whose method is called is args[0], and the args array starting at args[1] represents the arguments of the call. There must be at least one positional argument. nargsf is the number of positional arguments including args[0], plus PY_VECTORCALL_ARGUMENTS_OFFSET if the value of args[0] may temporarily be changed. Keyword arguments can be passed just like in PyObject_Vectorcall().

If the object has the Py_TPFLAGS_METHOD_DESCRIPTOR feature, this will call the unbound method object with the full args vector as arguments.

성공하면 호출 결과를 반환하고, 실패하면 예외를 발생시키고 NULL을 반환합니다.

Added in version 3.9.

호출 지원 API

int PyCallable_Check(PyObject *o)

Part of the Stable ABI.

객체 o가 콜러블 인지 판별합니다. 객체가 콜러블 이면 1을, 그렇지 않으면 0을 반환합니다. 이 함수는 항상 성공합니다.

숫자 프로토콜

int PyNumber_Check(PyObject *o)

Part of the Stable ABI.

객체 o가 숫자 프로토콜을 제공하면 1을 반환하고, 그렇지 않으면 거짓을 반환합니다. 이 함수는 항상 성공합니다.

버전 3.8에서 변경: o가 인덱스 정수면 1을 반환합니다.

PyObject *PyNumber_Add(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1과 o2를 더한 결과나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 + o2와 동등합니다.

PyObject *PyNumber_Subtract(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1에서 o2를 뺀 결과나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 - o2와 동등합니다.

PyObject *PyNumber_Multiply(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1과 o2를 곱한 결과나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 * o2와 동등합니다.

PyObject *PyNumber_MatrixMultiply(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI since version 3.7.

o1과 o2를 행렬 곱셈한 결과나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 @ o2와 동등합니다.

Added in version 3.5.

PyObject *PyNumber_FloorDivide(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

Return the floor of o1 divided by o2, or NULL on failure. This is the equivalent of the Python expression o1 // o2.

PyObject *PyNumber_TrueDivide(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

Return a reasonable approximation for the mathematical value of o1 divided by o2, or NULL on failure. The return value is “approximate” because binary floating-point numbers are approximate; it is not possible to represent all real numbers in base two. This function can return a floating-point value when passed two integers. This is the equivalent of the Python expression o1 / o2.

PyObject *PyNumber_Remainder(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1을 o2로 나눈 나머지나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 % o2와 동등합니다.

PyObject *PyNumber_Divmod(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

내장 함수 divmod()를 참조하십시오. 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 divmod(o1, o2)와 동등합니다.

PyObject *PyNumber_Power(PyObject *o1, PyObject *o2, PyObject *o3)

Return value: New reference. Part of the Stable ABI.

내장 함수 pow()를 참조하십시오. 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 pow(o1, o2, o3)와 동등합니다, 여기서 o3는 선택적입니다. o3를 무시하려면, 그 자리에 Py_None을 전달하십시오 (o3에 NULL을 전달하면 잘못된 메모리 액세스가 발생합니다).

PyObject *PyNumber_Negative(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 o의 음의 값(negation)을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 -o와 동등합니다.

PyObject *PyNumber_Positive(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 o를, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 +o와 동등합니다.

PyObject *PyNumber_Absolute(PyObject *o)

Return value: New reference. Part of the Stable ABI.

o의 절댓값이나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 abs(o)와 동등합니다.

PyObject *PyNumber_Invert(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 o의 비트 반전(bitwise negation)을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 ~o와 동등합니다.

PyObject *PyNumber_Lshift(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1을 o2만큼 왼쪽으로 시프트 한 결과를, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 << o2와 동등합니다.

PyObject *PyNumber_Rshift(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1을 o2만큼 오른쪽으로 시프트 한 결과를, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 >> o2와 동등합니다.

PyObject *PyNumber_And(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 논리곱(bitwise and)”을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 & o2와 동등합니다.

PyObject *PyNumber_Xor(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 배타적 논리합(bitwise exclusive or)”을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 ^ o2와 동등합니다.

PyObject *PyNumber_Or(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 논리합(bitwise or)”을, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o1 | o2와 동등합니다.

PyObject *PyNumber_InPlaceAdd(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1과 o2를 더한 결과나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 += o2와 동등합니다.

PyObject *PyNumber_InPlaceSubtract(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1에서 o2를 뺀 결과나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 -= o2와 동등합니다.

PyObject *PyNumber_InPlaceMultiply(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1과 o2를 곱한 결과나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 *= o2와 동등합니다.

PyObject *PyNumber_InPlaceMatrixMultiply(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI since version 3.7.

o1과 o2를 행렬 곱셈한 결과나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 @= o2와 동등합니다.

Added in version 3.5.

PyObject *PyNumber_InPlaceFloorDivide(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1을 o2로 나눈 수학적 플로어(floor)나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 //= o2와 동등합니다.

PyObject *PyNumber_InPlaceTrueDivide(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

Return a reasonable approximation for the mathematical value of o1 divided by o2, or NULL on failure. The return value is “approximate” because binary floating-point numbers are approximate; it is not possible to represent all real numbers in base two. This function can return a floating-point value when passed two integers. The operation is done in-place when o1 supports it. This is the equivalent of the Python statement o1 /= o2.

PyObject *PyNumber_InPlaceRemainder(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

o1을 o2로 나눈 나머지나, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 %= o2와 동등합니다.

PyObject *PyNumber_InPlacePower(PyObject *o1, PyObject *o2, PyObject *o3)

Return value: New reference. Part of the Stable ABI.

내장 함수 pow()를 참조하십시오. 실패하면 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 o3가 Py_None일 때 파이썬 문장 o1 **= o2와, 그렇지 않으면 pow(o1, o2, o3)의 제자리 변형과 동등합니다. o3를 무시하려면, 그 자리에 Py_None을 전달하십시오 (o3에 NULL을 전달하면 잘못된 메모리 액세스가 발생합니다).

PyObject *PyNumber_InPlaceLshift(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1을 o2만큼 왼쪽으로 시프트 한 결과를, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 <<= o2와 동등합니다.

PyObject *PyNumber_InPlaceRshift(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1을 o2만큼 오른쪽으로 시프트 한 결과를, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 >>= o2와 동등합니다.

PyObject *PyNumber_InPlaceAnd(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 논리곱(bitwise and)”을, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 &= o2와 동등합니다.

PyObject *PyNumber_InPlaceXor(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 배타적 논리합(bitwise exclusive or)”을, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 ^= o2와 동등합니다.

PyObject *PyNumber_InPlaceOr(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1과 o2의 “비트별 논리합(bitwise or)”을, 실패 시 NULL을 반환합니다. 이 연산은 o1이 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 문장 o1 |= o2와 동등합니다.

PyObject *PyNumber_Long(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 정수 객체로 변환된 o를, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 int(o)와 동등합니다.

PyObject *PyNumber_Float(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 float 객체로 변환된 o를, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 float(o)와 동등합니다.

PyObject *PyNumber_Index(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공 시 파이썬 int로 변환된 o를, 실패 시 NULL을 반환합니다. 실패 시 TypeError 예외가 발생합니다.

버전 3.10에서 변경: The result always has exact type int. Previously, the result could have been an instance of a subclass of int.

PyObject *PyNumber_ToBase(PyObject *n, int base)

Return value: New reference. Part of the Stable ABI.

정수 n을 진수 base를 사용해서 변환한 문자열을 반환합니다. base 인자는 2, 8, 10 또는 16중 하나여야 합니다. 진수 2, 8 또는 16의 경우, 반환된 문자열은 '0b', '0o' 또는 '0x'의 진수 표시자가 각각 앞에 붙습니다. n이 파이썬 int가 아니면, 먼저 PyNumber_Index()로 변환됩니다.

Py_ssize_t PyNumber_AsSsize_t(PyObject *o, PyObject *exc)

Part of the Stable ABI.

Returns o converted to a Py_ssize_t value if o can be interpreted as an integer. If the call fails, an exception is raised and -1 is returned.

If o can be converted to a Python int but the attempt to convert to a Py_ssize_t value would raise an OverflowError, then the exc argument is the type of exception that will be raised (usually IndexError or OverflowError). If exc is NULL, then the exception is cleared and the value is clipped to PY_SSIZE_T_MIN for a negative integer or PY_SSIZE_T_MAX for a positive integer.

int PyIndex_Check(PyObject *o)

Part of the Stable ABI since version 3.8.

Returns 1 if o is an index integer (has the nb_index slot of the tp_as_number structure filled in), and 0 otherwise. This function always succeeds.

시퀀스 프로토콜

int PySequence_Check(PyObject *o)

Part of the Stable ABI.

Return 1 if the object provides the sequence protocol, and 0 otherwise. Note that it returns 1 for Python classes with a __getitem__() method, unless they are dict subclasses, since in general it is impossible to determine what type of keys the class supports. This function always succeeds.

Py_ssize_t PySequence_Size(PyObject *o)

Py_ssize_t PySequence_Length(PyObject *o)

Part of the Stable ABI.

성공 시 시퀀스 o의 객체 수를 반환하고, 실패하면 -1을 반환합니다. 이것은 파이썬 표현식 len(o)와 동등합니다.

PyObject *PySequence_Concat(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1와 o2의 이어붙이기를 반환하고, 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 o1 + o2와 동등합니다.

PyObject *PySequence_Repeat(PyObject *o, Py_ssize_t count)

Return value: New reference. Part of the Stable ABI.

시퀸스 객체 o를 count 번 반복한 결과를 반환하거나, 실패 시 NULL을 반환합니다. 이것은 파이썬 표현식 o * count와 동등합니다.

PyObject *PySequence_InPlaceConcat(PyObject *o1, PyObject *o2)

Return value: New reference. Part of the Stable ABI.

성공 시 o1와 o2의 이어붙이기를 반환하고, 실패하면 NULL을 반환합니다. 이 연산은 o1가 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 표현식 o1 += o2와 동등합니다.

PyObject *PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count)

Return value: New reference. Part of the Stable ABI.

시퀸스 객체 o를 count 번 반복한 결과를 반환하거나, 실패 시 NULL을 반환합니다. 이 연산은 o가 지원하면 제자리에서(in-place) 수행됩니다. 이것은 파이썬 표현식 o *= count와 동등합니다.

PyObject *PySequence_GetItem(PyObject *o, Py_ssize_t i)

Return value: New reference. Part of the Stable ABI.

o의 i 번째 요소를 반환하거나, 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 o[i]와 동등합니다.

PyObject *PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)

Return value: New reference. Part of the Stable ABI.

시퀀스 객체 o의 i1와 i2 사이의 슬라이스를 반환하거나, 실패하면 NULL을 반환합니다. 이것은 파이썬 표현식 o[i1:i2]와 동등합니다.

int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v)

Part of the Stable ABI.

객체 v를 o의 i 번째 요소에 대입합니다. 실패하면 예외를 발생시키고 -1을 반환합니다; 성공하면 0을 반환합니다. 이것은 파이썬 문장 o[i] = v와 동등합니다. 이 함수는 v에 대한 참조를 훔치지 않습니다.

If v is NULL, the element is deleted, but this feature is deprecated in favour of using PySequence_DelItem().

int PySequence_DelItem(PyObject *o, Py_ssize_t i)

Part of the Stable ABI.

o 객체의 i 번째 요소를 삭제합니다. 실패하면 -1을 반환합니다. 이것은 파이썬 문장 del o[i]와 동등합니다.

int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v)

Part of the Stable ABI.

시퀀스 객체 v를 시퀀스 객체 o의 i1에서 i2 사이의 슬라이스에 대입합니다. 이것은 파이썬 문장 o[i1:i2] = v와 동등합니다.

int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)

Part of the Stable ABI.

시퀀스 객체 o의 i1에서 i2 사이의 슬라이스를 삭제합니다. 실패하면 -1을 반환합니다. 이것은 파이썬 문장 del o[i1:i2]와 동등합니다.

Py_ssize_t PySequence_Count(PyObject *o, PyObject *value)

Part of the Stable ABI.

o에 있는 value의 수를 반환합니다. 즉, o[key] == value를 만족하는 key의 수를 반환합니다. 실패하면 -1을 반환합니다. 이것은 파이썬 표현식 o.count(value)와 동등합니다.

int PySequence_Contains(PyObject *o, PyObject *value)

Part of the Stable ABI.

o에 value가 있는지 확인합니다. o의 항목 중 하나가 value와 같으면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 에러 시 -1을 반환합니다. 이는 파이썬 표현식 value in o와 동등합니다.

Py_ssize_t PySequence_Index(PyObject *o, PyObject *value)

Part of the Stable ABI.

o[i] == value을 만족하는 첫 번째 인덱스 i를 반환합니다. 에러 시 -1을 반환합니다. 이것은 파이썬 표현식 o.index(value)와 동등합니다.

PyObject *PySequence_List(PyObject *o)

Return value: New reference. Part of the Stable ABI.

시퀀스나 이터러블 o와 같은 내용을 가진 리스트 객체를 반환하거나, 실패하면 NULL을 반환합니다. 반환된 리스트는 새로운 것으로 보장됩니다. 이것은 파이썬 표현식 list(o)와 동등합니다.

PyObject *PySequence_Tuple(PyObject *o)

Return value: New reference. Part of the Stable ABI.

시퀀스나 이터러블 o와 같은 내용을 가진 튜플 객체를 반환하거나, 실패하면 NULL을 반환합니다. o가 튜플이면, 새로운 참조가 반환되고, 그렇지 않으면 튜플이 적절한 내용으로 만들어집니다. 이것은 파이썬 표현식 tuple(o)와 동등합니다.

PyObject *PySequence_Fast(PyObject *o, const char *m)

Return value: New reference. Part of the Stable ABI.

시퀀스나 이터러블 o를 다른 PySequence_Fast* 계열 함수에서 사용할 수 있는 객체로 반환합니다. 객체가 시퀀스나 이터러블이 아니면 m을 메시지 텍스트로 사용하여 TypeError를 발생시킵니다. 실패 시 NULL을 반환합니다.

PySequence_Fast* 함수는 o가 PyTupleObject나 PyListObject라고 가정하고 o의 데이터 필드에 직접 액세스하기 때문에 이렇게 이름 붙였습니다.

CPython 구현 세부 사항으로, o가 이미 시퀀스나 리스트면, 반환됩니다.

Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)

Returns the length of o, assuming that o was returned by PySequence_Fast() and that o is not NULL. The size can also be retrieved by calling PySequence_Size() on o, but PySequence_Fast_GET_SIZE() is faster because it can assume o is a list or tuple.

PyObject *PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)

Return value: Borrowed reference.

o의 i 번째 요소를 반환하는데, o가 PySequence_Fast()에 의해 반환되었고, o가 NULL이 아니며, i가 경계 내에 있다고 가정합니다.

PyObject **PySequence_Fast_ITEMS(PyObject *o)

PyObject 포인터의 하부 배열을 반환합니다. o가 PySequence_Fast()에 의해 반환되었고, o가 NULL이 아니라고 가정합니다.

리스트의 크기가 변경되면, 재할당이 항목 배열을 재배치할 수 있음에 유의하십시오. 따라서, 시퀀스가 변경될 수 없는 문맥에서만 하부 배열 포인터를 사용하십시오.

PyObject *PySequence_ITEM(PyObject *o, Py_ssize_t i)

Return value: New reference.

o의 i 번째 요소를 반환하거나, 실패하면 NULL을 반환합니다. PySequence_GetItem()의 빠른 형식이지만, o에 대해 PySequence_Check()가 참인지 검사하지 않고, 음수 인덱스를 조정하지 않습니다.

매핑 프로토콜

PyObject_GetItem(), PyObject_SetItem() 및 PyObject_DelItem()도 참조하십시오.

int PyMapping_Check(PyObject *o)

Part of the Stable ABI.

Return 1 if the object provides the mapping protocol or supports slicing, and 0 otherwise. Note that it returns 1 for Python classes with a __getitem__() method, since in general it is impossible to determine what type of keys the class supports. This function always succeeds.

Py_ssize_t PyMapping_Size(PyObject *o)

Py_ssize_t PyMapping_Length(PyObject *o)

Part of the Stable ABI.

성공 시 객체 o의 키 수를 반환하고, 실패하면 -1을 반환합니다. 이는 파이썬 표현식 len(o)와 동등합니다.

PyObject *PyMapping_GetItemString(PyObject *o, const char *key)

Return value: New reference. Part of the Stable ABI.

This is the same as PyObject_GetItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyMapping_GetOptionalItem(PyObject *obj, PyObject *key, PyObject **result)

Part of the Stable ABI since version 3.13.

Variant of PyObject_GetItem() which doesn’t raise KeyError if the key is not found.

If the key is found, return 1 and set *result to a new strong reference to the corresponding value. If the key is not found, return 0 and set *result to NULL; the KeyError is silenced. If an error other than KeyError is raised, return -1 and set *result to NULL.

Added in version 3.13.

int PyMapping_GetOptionalItemString(PyObject *obj, const char *key, PyObject **result)

Part of the Stable ABI since version 3.13.

This is the same as PyMapping_GetOptionalItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

int PyMapping_SetItemString(PyObject *o, const char *key, PyObject *v)

Part of the Stable ABI.

This is the same as PyObject_SetItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyMapping_DelItem(PyObject *o, PyObject *key)

This is an alias of PyObject_DelItem().

int PyMapping_DelItemString(PyObject *o, const char *key)

This is the same as PyObject_DelItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyMapping_HasKeyWithError(PyObject *o, PyObject *key)

Part of the Stable ABI since version 3.13.

Return 1 if the mapping object has the key key and 0 otherwise. This is equivalent to the Python expression key in o. On failure, return -1.

Added in version 3.13.

int PyMapping_HasKeyStringWithError(PyObject *o, const char *key)

Part of the Stable ABI since version 3.13.

This is the same as PyMapping_HasKeyWithError(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

int PyMapping_HasKey(PyObject *o, PyObject *key)

Part of the Stable ABI.

매핑 객체에 key 키가 있으면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 이는 파이썬 표현식 key in o와 동등합니다. 이 함수는 항상 성공합니다.

참고

Exceptions which occur when this calls __getitem__() method are silently ignored. For proper error handling, use PyMapping_HasKeyWithError(), PyMapping_GetOptionalItem() or PyObject_GetItem() instead.

int PyMapping_HasKeyString(PyObject *o, const char *key)

Part of the Stable ABI.

This is the same as PyMapping_HasKey(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

참고

Exceptions that occur when this calls __getitem__() method or while creating the temporary str object are silently ignored. For proper error handling, use PyMapping_HasKeyStringWithError(), PyMapping_GetOptionalItemString() or PyMapping_GetItemString() instead.

PyObject *PyMapping_Keys(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공하면, 객체 o의 키 리스트를 반환합니다. 실패하면, NULL을 반환합니다.

버전 3.7에서 변경: 이전에는 함수가 리스트나 튜플을 반환했습니다.

PyObject *PyMapping_Values(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공하면, 객체 o의 값 리스트를 반환합니다. 실패하면, NULL을 반환합니다.

버전 3.7에서 변경: 이전에는 함수가 리스트나 튜플을 반환했습니다.

PyObject *PyMapping_Items(PyObject *o)

Return value: New reference. Part of the Stable ABI.

성공하면, 객체 o에 있는 항목 리스트를 반환합니다. 여기서 각 항목은 키-값 쌍을 포함하는 튜플입니다. 실패하면, NULL을 반환합니다.

버전 3.7에서 변경: 이전에는 함수가 리스트나 튜플을 반환했습니다.

이터레이터 프로토콜

특히 이터레이터를 사용하기 위한 두 함수가 있습니다.

int PyIter_Check(PyObject *o)

Part of the Stable ABI since version 3.8.

Return non-zero if the object o can be safely passed to PyIter_NextItem() and 0 otherwise. This function always succeeds.

int PyAIter_Check(PyObject *o)

Part of the Stable ABI since version 3.10.

Return non-zero if the object o provides the AsyncIterator protocol, and 0 otherwise. This function always succeeds.

Added in version 3.10.

int PyIter_NextItem(PyObject *iter, PyObject **item)

Part of the Stable ABI since version 3.14.

Return 1 and set item to a strong reference of the next value of the iterator iter on success. Return 0 and set item to NULL if there are no remaining values. Return -1, set item to NULL and set an exception on error.

Added in version 3.14.

PyObject *PyIter_Next(PyObject *o)

Return value: New reference. Part of the Stable ABI.

This is an older version of PyIter_NextItem(), which is retained for backwards compatibility. Prefer PyIter_NextItem().

Return the next value from the iterator o. The object must be an iterator according to PyIter_Check() (it is up to the caller to check this). If there are no remaining values, returns NULL with no exception set. If an error occurs while retrieving the item, returns NULL and passes along the exception.

type PySendResult

The enum value used to represent different results of PyIter_Send().

Added in version 3.10.

PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)

Part of the Stable ABI since version 3.10.

Sends the arg value into the iterator iter. Returns:

PYGEN_RETURN if iterator returns. Return value is returned via presult.

PYGEN_NEXT if iterator yields. Yielded value is returned via presult.

PYGEN_ERROR if iterator has raised and exception. presult is set to NULL.

Added in version 3.10.

버퍼 프로토콜

파이썬에서 사용할 수 있는 어떤 객체는 하부 메모리 배열 또는 버퍼에 대한 액세스를 감쌉니다. 이러한 객체에는 내장 bytes 와 bytearray, 그리고 array.array와 같은 일부 확장형이 포함됩니다. 제삼자 라이브러리도 이미지 처리나 수치 해석과 같은 특수한 용도로 자체 형을 정의할 수 있습니다.

이러한 형은 각각 고유의 의미가 있지만, (아마도) 큰 메모리 버퍼에 의해 뒷받침되는 공통된 특징을 공유합니다. 어떤 상황에서는 중간 복사 없이 직접 버퍼에 액세스하는 것이 바람직합니다.

파이썬은 C 수준에서 버퍼 프로토콜 형식으로 이러한 기능을 제공합니다. 이 프로토콜에는 두 가지 측면이 있습니다:

생산자 측에서는, 형이 “버퍼 인터페이스”를 내보낼 수 있는데, 그 형의 객체가 하부 버퍼의 정보를 노출할 수 있게 합니다. 이 인터페이스는 버퍼 객체 구조체 절에서 설명됩니다.

소비자 측에서는, 객체의 원시 하부 데이터에 대한 포인터를 얻기 위해 여러 가지 방법을 사용할 수 있습니다 (예를 들어 메서드 매개 변수).

bytes 와 bytearray와 같은 간단한 객체는 하부 버퍼를 바이트 지향 형식으로 노출합니다. 다른 형태도 가능합니다; 예를 들어, array.array에 의해 노출되는 요소는 멀티 바이트 값이 될 수 있습니다.

An example consumer of the buffer interface is the write() method of file objects: any object that can export a series of bytes through the buffer interface can be written to a file. While write() only needs read-only access to the internal contents of the object passed to it, other methods such as readinto() need write access to the contents of their argument. The buffer interface allows objects to selectively allow or reject exporting of read-write and read-only buffers.

버퍼 인터페이스의 소비자가 대상 객체에 대해 버퍼를 얻는 방법에는 두 가지가 있습니다:

올바른 매개 변수로 PyObject_GetBuffer()를 호출합니다;

y*, w* 또는 s* 형식 코드 중 하나를 사용하여 PyArg_ParseTuple()(또는 그 형제 중 하나)을 호출합니다.

두 경우 모두, 버퍼가 더는 필요하지 않으면 PyBuffer_Release()를 호출해야 합니다. 그렇게 하지 않으면 자원 누수와 같은 다양한 문제가 발생할 수 있습니다.

버퍼 구조체

버퍼 구조체(또는 단순히 “버퍼”)는 다른 객체의 바이너리 데이터를 파이썬 프로그래머에게 노출하는 방법으로 유용합니다. 또한, 복사 없는(zero-copy) 슬라이싱 메커니즘으로 사용할 수 있습니다. 메모리 블록을 참조하는 능력을 사용해서, 임의의 데이터를 파이썬 프로그래머에게 아주 쉽게 노출할 수 있습니다. 메모리는 C 확장의 큰 상수 배열일 수 있으며, 운영 체제 라이브러리로 전달되기 전에 조작하기 위한 원시 메모리 블록일 수도 있고, 네이티브 인 메모리(in-memory) 형식으로 구조화된 데이터를 전달하는 데 사용될 수도 있습니다.

파이썬 인터프리터가 노출하는 대부분의 데이터형과 달리, 버퍼는 PyObject 포인터가 아니라 단순한 C 구조체입니다. 이를 통해 매우 간단하게 만들고 복사할 수 있습니다. 버퍼를 감싸는 일반 래퍼가 필요할 때는, 메모리 뷰 객체를 만들 수 있습니다.

제공하는(exporting) 객체를 작성하는 간단한 지침은 버퍼 객체 구조체를 참조하십시오. 버퍼를 얻으려면, PyObject_GetBuffer()를 참조하십시오.

type Py_buffer

Part of the Stable ABI (including all members) since version 3.11.

void *buf

버퍼 필드에 의해 기술된 논리적 구조의 시작을 가리키는 포인터. 이것은 제공자(exporter)의 하부 물리적 메모리 블록 내의 모든 위치일 수 있습니다. 예를 들어, 음의 strides를 사용하면 값이 메모리 블록의 끝을 가리킬 수 있습니다.

연속 배열의 경우, 값은 메모리 블록의 시작을 가리킵니다.

PyObject *obj

A new reference to the exporting object. The reference is owned by the consumer and automatically released (i.e. reference count decremented) and set to NULL by PyBuffer_Release(). The field is the equivalent of the return value of any standard C-API function.

특수한 경우로, PyMemoryView_FromBuffer() 나 PyBuffer_FillInfo()로 감싸진 임시(temporary) 버퍼의 경우, 이 필드는 NULL입니다. 일반적으로, 제공하는(exporting) 객체는 이 체계를 사용하지 않아야 합니다.

Py_ssize_t len

product(shape) * itemsize. 연속 배열의 경우, 하부 메모리 블록의 길이입니다. 불연속 배열의 경우, 연속 표현으로 복사된다면 논리적 구조체가 갖게 될 길이입니다.

((char *)buf)[0] 에서 ((char *)buf)[len-1] 범위의 액세스는 연속성을 보장하는 요청으로 버퍼가 확보된 경우에만 유효합니다. 대부분 이러한 요청은 PyBUF_SIMPLE 또는 PyBUF_WRITABLE입니다.

int readonly

버퍼가 읽기 전용인지를 나타내는 표시기입니다. 이 필드는 PyBUF_WRITABLE 플래그로 제어됩니다.

Py_ssize_t itemsize

단일 요소의 항목 크기(바이트)입니다. NULL이 아닌 format 값에 호출된 struct.calcsize() 값과 같습니다.

중요한 예외: 소비자가 PyBUF_FORMAT 플래그 없이 버퍼를 요청하면, format은 NULL로 설정되지만, itemsize는 여전히 원래 형식의 값을 갖습니다.

shape이 있으면, product(shape) * itemsize == len 동치가 계속 성립하고 소비자는 itemsize를 사용하여 버퍼를 탐색할 수 있습니다.

PyBUF_SIMPLE 이나 PyBUF_WRITABLE 요청의 결과로 shape이 NULL이면, 소비자는 itemsize를 무시하고 itemsize == 1로 가정해야 합니다.

char *format

A NULL terminated string in struct module style syntax describing the contents of a single item. If this is NULL, "B" (unsigned bytes) is assumed.

이 필드는 PyBUF_FORMAT 플래그로 제어됩니다.

int ndim

The number of dimensions the memory represents as an n-dimensional array. If it is 0, buf points to a single item representing a scalar. In this case, shape, strides and suboffsets MUST be NULL. The maximum number of dimensions is given by PyBUF_MAX_NDIM.

Py_ssize_t *shape

n-차원 배열로 메모리의 모양을 나타내는 길이 ndim의 Py_ssize_t 배열. shape[0] * ... * shape[ndim-1] * itemsize는 len과 같아야 합니다.

모양 값은 shape[n] >= 0로 제한됩니다. shape[n] == 0인 경우는 특별한 주의가 필요합니다. 자세한 정보는 복잡한 배열을 참조하십시오.

shape 배열은 소비자에게 읽기 전용입니다.

Py_ssize_t *strides

각 차원에서 새 요소를 가져오기 위해 건너뛸 바이트 수를 제공하는 길이 ndim의 Py_ssize_t 배열.

스트라이드 값은 임의의 정수일 수 있습니다. 일반 배열의 경우, 스트라이드는 보통 양수이지만, 소비자는 strides[n] <= 0인 경우를 처리할 수 있어야 합니다. 자세한 내용은 복잡한 배열을 참조하십시오.

strides 배열은 소비자에게 읽기 전용입니다.

Py_ssize_t *suboffsets

길이 ndim의 Py_ssize_t 배열. suboffsets[n] >= 0 면, n 번째 차원을 따라 저장된 값은 포인터이고 서브 오프셋 값은 역참조(de-referencing) 후 각 포인터에 더할 바이트 수를 나타냅니다. 음의 서브 오프셋 값은 역참조(de-referencing)가 발생하지 않아야 함을 나타냅니다 (연속 메모리 블록에서의 스트라이드).

모든 서브 오프셋이 음수면 (즉, 역참조가 필요하지 않으면), 이 필드는 NULL(기본값) 이어야 합니다.

이 유형의 배열 표현은 파이썬 이미징 라이브러리(PIL)에서 사용됩니다. 이러한 배열 요소에 액세스하는 방법에 대한 자세한 내용은 복잡한 배열을 참조하십시오.

suboffsets 배열은 소비자에게 읽기 전용입니다.

void *internal

이것은 제공하는(exporting) 객체에 의해 내부적으로 사용됩니다. 예를 들어, 이것은 제공자(exporter)가 정수로 다시 캐스팅할 수 있으며, 버퍼가 해제될 때 shape, strides 및 suboffsets 배열을 해제해야 하는지에 대한 플래그를 저장하는 데 사용됩니다. 소비자가 이 값을 변경해서는 안 됩니다.

Constants:

PyBUF_MAX_NDIM

The maximum number of dimensions the memory represents. Exporters MUST respect this limit, consumers of multi-dimensional buffers SHOULD be able to handle up to PyBUF_MAX_NDIM dimensions. Currently set to 64.

버퍼 요청 유형

버퍼는 대개 PyObject_GetBuffer()를 통해 제공하는(exporting) 객체로 버퍼 요청을 보내서 얻습니다. 메모리의 논리적 구조의 복잡성이 크게 다를 수 있으므로, 소비자는 처리할 수 있는 정확한 버퍼 유형을 지정하기 위해 flags 인자를 사용합니다.

All Py_buffer fields are unambiguously defined by the request type.

요청 독립적 필드

다음 필드는 flags의 영향을 받지 않고 항상 올바른 값으로 채워져야 합니다: obj, buf, len, itemsize, ndim.

readonly, format

PyBUF_WRITABLE

Controls the readonly field. If set, the exporter MUST provide a writable buffer or else report failure. Otherwise, the exporter MAY provide either a read-only or writable buffer, but the choice MUST be consistent for all consumers. For example, PyBUF_SIMPLE | PyBUF_WRITABLE can be used to request a simple writable buffer.

PyBUF_FORMAT

format 필드를 제어합니다. 설정되면, 이 필드를 올바르게 채워야 합니다. 그렇지 않으면, 이 필드는 반드시 NULL 이어야 합니다.

PyBUF_WRITABLE은 다음 섹션의 모든 플래그와 | 될 수 있습니다. PyBUF_SIMPLE이 0으로 정의되므로, PyBUF_WRITABLE은 독립형 플래그로 사용되어 간단한 쓰기 가능한 버퍼를 요청할 수 있습니다.

PyBUF_FORMAT must be |’d to any of the flags except PyBUF_SIMPLE, because the latter already implies format B (unsigned bytes). PyBUF_FORMAT cannot be used on its own.

shape, strides, suboffsets

메모리의 논리 구조를 제어하는 플래그는 복잡도가 감소하는 순서로 나열됩니다. 각 플래그는 그 아래에 있는 플래그의 모든 비트를 포함합니다.

요청

shape

strides

suboffsets

PyBUF_INDIRECT

yes

yes

필요하면

PyBUF_STRIDES

yes

yes

NULL

PyBUF_ND

yes

NULL

NULL

PyBUF_SIMPLE

NULL

NULL

NULL

연속성 요청

C 나 포트란 연속성을 명시적으로 요청할 수 있는데, 스트라이드 정보를 포함하기도 그렇지 않기도 합니다. 스트라이드 정보가 없으면, 버퍼는 C-연속이어야 합니다.

요청

shape

strides

suboffsets

연속성

PyBUF_C_CONTIGUOUS

yes

yes

NULL

C

PyBUF_F_CONTIGUOUS

yes

yes

NULL

F

PyBUF_ANY_CONTIGUOUS

yes

yes

NULL

C 또는 F

PyBUF_ND

yes

NULL

NULL

C

복합 요청

모든 가능한 요청은 앞 절의 플래그 조합에 의해 완전히 정의됩니다. 편의상, 버퍼 프로토콜은 자주 사용되는 조합을 단일 플래그로 제공합니다.

다음 표에서 U는 정의되지 않은 연속성을 나타냅니다. 소비자는 연속성을 판단하기 위해 PyBuffer_IsContiguous()를 호출해야 합니다.

요청

shape

strides

suboffsets

연속성

readonly

format

PyBUF_FULL

yes

yes

필요하면

U

0

yes

PyBUF_FULL_RO

yes

yes

필요하면

U

1 또는 0

yes

PyBUF_RECORDS

yes

yes

NULL

U

0

yes

PyBUF_RECORDS_RO

yes

yes

NULL

U

1 또는 0

yes

PyBUF_STRIDED

yes

yes

NULL

U

0

NULL

PyBUF_STRIDED_RO

yes

yes

NULL

U

1 또는 0

NULL

PyBUF_CONTIG

yes

NULL

NULL

C

0

NULL

PyBUF_CONTIG_RO

yes

NULL

NULL

C

1 또는 0

NULL

복잡한 배열

NumPy-스타일: shape과 strides

NumPy 스타일 배열의 논리적 구조는 itemsize, ndim, shape 및 strides로 정의됩니다.

ndim == 0이면, buf가 가리키는 메모리 위치가 itemsize 크기의 스칼라로 해석됩니다. 이 경우, shape 과 strides는 모두 NULL입니다.

strides가 NULL이면, 배열은 표준 n-차원 C 배열로 해석됩니다. 그렇지 않으면, 소비자는 다음과 같이 n-차원 배열에 액세스해야 합니다:

ptr = (char *)buf + indices[0] * strides[0] + ... + indices[n-1] * strides[n-1];
item = *((typeof(item) *)ptr);

위에서 언급했듯이, buf는 실제 메모리 블록 내의 모든 위치를 가리킬 수 있습니다. 제공자(exporter)는 이 함수로 버퍼의 유효성을 검사 할 수 있습니다:

def verify_structure(memlen, itemsize, ndim, shape, strides, offset):
    """Verify that the parameters represent a valid array within
       the bounds of the allocated memory:
           char *mem: start of the physical memory block
           memlen: length of the physical memory block
           offset: (char *)buf - mem
    """
    if offset % itemsize:
        return False
    if offset < 0 or offset+itemsize > memlen:
        return False
    if any(v % itemsize for v in strides):
        return False

    if ndim <= 0:
        return ndim == 0 and not shape and not strides
    if 0 in shape:
        return True

    imin = sum(strides[j]*(shape[j]-1) for j in range(ndim)
               if strides[j] <= 0)
    imax = sum(strides[j]*(shape[j]-1) for j in range(ndim)
               if strides[j] > 0)

    return 0 <= offset+imin and offset+imax+itemsize <= memlen

PIL-스타일: shape, strides 및 suboffsets

일반 항목 외에도, PIL 스타일 배열에는 차원의 다음 요소를 가져오기 위해 따라야 하는 포인터가 포함될 수 있습니다. 예를 들어, 일반 3-차원 C 배열 char v[2][2][3]는 2개의 2-차원 배열을 가리키는 2개의 포인터 배열로 볼 수도 있습니다: char (*v[2])[2][3]. suboffsets 표현에서, 이 두 포인터는 buf의 시작 부분에 임베드 될 수 있는데, 메모리의 어느 위치 에나 배치될 수 있는 두 개의 char x[2][3] 배열을 가리킵니다.

다음은 NULL이 아닌 strides와 suboffsets가 있을 때, N-차원 인덱스가 가리키는 N-차원 배열의 요소에 대한 포인터를 반환하는 함수입니다:

void *get_item_pointer(int ndim, void *buf, Py_ssize_t *strides,
                       Py_ssize_t *suboffsets, Py_ssize_t *indices) {
    char *pointer = (char*)buf;
    int i;
    for (i = 0; i < ndim; i++) {
        pointer += strides[i] * indices[i];
        if (suboffsets[i] >=0 ) {
            pointer = *((char**)pointer) + suboffsets[i];
        }
    }
    return (void*)pointer;
}

버퍼 관련 함수

int PyObject_CheckBuffer(PyObject *obj)

Part of the Stable ABI since version 3.11.

obj가 버퍼 인터페이스를 지원하면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 1이 반환될 때, PyObject_GetBuffer()가 성공할 것이라고 보장하지는 않습니다. 이 함수는 항상 성공합니다.

int PyObject_GetBuffer(PyObject *exporter, Py_buffer *view, int flags)

Part of the Stable ABI since version 3.11.

Send a request to exporter to fill in view as specified by flags. If the exporter cannot provide a buffer of the exact type, it MUST raise BufferError, set view->obj to NULL and return -1.

성공하면, view를 채우고, view->obj를 exporter에 대한 새 참조로 설정하고, 0을 반환합니다. 요청을 단일 객체로 리디렉션하는 연결된(chained) 버퍼 공급자의 경우, view->obj는 exporter 대신 이 객체를 참조할 수 있습니다 (버퍼 객체 구조체를 보세요).

PyObject_GetBuffer()에 대한 성공적인 호출은 PyBuffer_Release()에 대한 호출과 쌍을 이루어야 합니다, malloc()과 free()와 유사합니다. 따라서, 소비자가 버퍼로 작업한 후에는, PyBuffer_Release()를 정확히 한 번 호출해야 합니다.

void PyBuffer_Release(Py_buffer *view)

Part of the Stable ABI since version 3.11.

Release the buffer view and release the strong reference (i.e. decrement the reference count) to the view’s supporting object, view->obj. This function MUST be called when the buffer is no longer being used, otherwise reference leaks may occur.

PyObject_GetBuffer()를 통해 얻지 않은 버퍼에 이 함수를 호출하는 것은 에러입니다.

Py_ssize_t PyBuffer_SizeFromFormat(const char *format)

Part of the Stable ABI since version 3.11.

Return the implied itemsize from format. On error, raise an exception and return -1.

Added in version 3.9.

int PyBuffer_IsContiguous(const Py_buffer *view, char order)

Part of the Stable ABI since version 3.11.

view로 정의된 메모리가 C 스타일(order가 'C')이나 포트란 스타일(order가 'F') 연속이거나 둘 중 하나(order가 'A')면 1을 반환합니다. 그렇지 않으면 0을 반환합니다. 이 함수는 항상 성공합니다.

void *PyBuffer_GetPointer(const Py_buffer *view, const Py_ssize_t *indices)

Part of the Stable ABI since version 3.11.

주어진 view 내부의 indices가 가리키는 메모리 영역을 가져옵니다. indices는 view->ndim 인덱스의 배열을 가리켜야 합니다.

int PyBuffer_FromContiguous(const Py_buffer *view, const void *buf, Py_ssize_t len, char fort)

Part of the Stable ABI since version 3.11.

buf에 있는 연속된 len 바이트를 view로 복사합니다. fort는 'C' 또는 'F'(C 스타일 또는 포트란 스타일 순서)일 수 있습니다. 성공하면 0이 반환되고, 에러가 있으면 -1이 반환됩니다.

int PyBuffer_ToContiguous(void *buf, const Py_buffer *src, Py_ssize_t len, char order)

Part of the Stable ABI since version 3.11.

src에 있는 len 바이트를 buf에 연속 표현으로 복사합니다. order는 'C' 또는 'F' 또는 'A'(C 스타일 또는 포트란 스타일 순서 또는 둘 중 하나)일 수 있습니다. 성공하면 0이 반환되고, 에러가 있으면 -1이 반환됩니다.

이 함수는 len != src->len이면 실패합니다.

int PyObject_CopyData(PyObject *dest, PyObject *src)

Part of the Stable ABI since version 3.11.

Copy data from src to dest buffer. Can convert between C-style and or Fortran-style buffers.

0 is returned on success, -1 on error.

void PyBuffer_FillContiguousStrides(int ndims, Py_ssize_t *shape, Py_ssize_t *strides, int itemsize, char order)

Part of the Stable ABI since version 3.11.

strides 배열을 주어진 요소당 바이트 수와 주어진 shape 으로 연속 (order가 'C'면 C 스타일, order가 'F'면 포트란 스타일) 배열의 바이트 스트라이드로 채웁니다.

int PyBuffer_FillInfo(Py_buffer *view, PyObject *exporter, void *buf, Py_ssize_t len, int readonly, int flags)

Part of the Stable ABI since version 3.11.

readonly에 따라 쓰기 가능성이 설정된 len 크기의 buf를 노출하려는 제공자(exporter)에 대한 버퍼 요청을 처리합니다. buf는 부호 없는 바이트의 시퀀스로 해석됩니다.

flags 인자는 요청 유형을 나타냅니다. 이 함수는 buf가 읽기 전용으로 지정되고 PyBUF_WRITABLE이 flags에 설정되어 있지 않으면, 항상 플래그가 지정하는 대로 view를 채웁니다.

On success, set view->obj to a new reference to exporter and return 0. Otherwise, raise BufferError, set view->obj to NULL and return -1;

이 함수가 getbufferproc의 일부로 사용되면, exporter가 제공하는(exporting) 객체로 설정되어야 하고, flags는 수정되지 않은 채로 전달되어야 합니다. 그렇지 않으면 exporter가 NULL이어야 합니다.

구상 객체 계층

이 장의 함수는 특정 파이썬 객체 형에게만 적용됩니다. 그들에게 잘못된 형의 객체를 전달하는 것은 좋은 생각이 아닙니다; 파이썬 프로그램에서 객체를 받았는데 올바른 형을 가졌는지 확실하지 않다면, 먼저 형 검사를 수행해야 합니다; 예를 들어, 객체가 딕셔너리인지 확인하려면, PyDict_Check()를 사용하십시오. 이 장은 파이썬 객체 형의 “족보”처럼 구성되어 있습니다.

경고

이 장에서 설명하는 함수는 전달되는 객체의 형을 주의 깊게 검사하지만, 많은 함수는 유효한 객체 대신 전달되는 NULL을 확인하지 않습니다. NULL을 전달하면 메모리 액세스 위반이 발생하고 인터프리터가 즉시 종료될 수 있습니다.

기본 객체

이 절에서는 파이썬 형 객체와 싱글톤 객체 None에 대해 설명합니다.

형 객체

힙에 할당된 형 만들기

None 객체

숫자 객체

정수 객체

불리언 객체

Floating-Point Objects

Pack and Unpack functions

Pack functions

Unpack functions

복소수 객체

C 구조체로서의 복소수

파이썬 객체로서의 복소수

시퀀스 객체

시퀀스 객체에 대한 일반적인 연산은 이전 장에서 논의했습니다; 이 절에서는 파이썬 언어에 고유한 특정 종류의 시퀀스 객체를 다룹니다.

바이트열 객체

바이트 배열 객체

형 검사 매크로

직접 API 함수

매크로

유니코드 객체와 코덱

유니코드 객체

유니코드 형

유니코드 문자 속성

유니코드 문자열 생성과 액세스

로케일 인코딩

파일 시스템 인코딩

wchar_t 지원

내장 코덱

일반 코덱

UTF-8 코덱

UTF-32 코덱

UTF-16 코덱

UTF-7 코덱

유니코드 이스케이프 코덱

원시 유니코드 이스케이프 코덱

Latin-1 코덱

ASCII 코덱

문자 맵 코덱

윈도우 용 MBCS 코덱

메서드와 슬롯

메서드와 슬롯 함수

PyUnicodeWriter

튜플 객체

구조체 시퀀스 객체

리스트 객체

컨테이너 객체

딕셔너리 객체

집합 객체

함수 객체

함수 객체

인스턴스 메서드 객체

메서드 객체

셀 객체

코드 객체

Extra information

기타 객체

파일 객체

모듈 객체

C 모듈 초기화

단단계 초기화

다단계 초기화

저수준 모듈 생성 함수

지원 함수

모듈 조회

이터레이터 객체

디스크립터 객체

슬라이스 객체

Ellipsis 객체

MemoryView 객체

약한 참조 객체

캡슐

Frame Objects

Internal Frames

제너레이터 객체

코루틴 객체

컨텍스트 변수 객체

DateTime 객체

Objects for Type Hinting

형 객체

type PyTypeObject

Part of the Limited API (as an opaque struct).

내장형을 기술하는 데 사용되는 객체의 C 구조체.

PyTypeObject PyType_Type

Part of the Stable ABI.

이것은 형 객체의 형 객체입니다; 파이썬 계층의 type과 같은 객체입니다.

int PyType_Check(PyObject *o)

객체 o가 표준형 객체에서 파생된 형의 인스턴스를 포함하여 형 객체면 0이 아닌 값을 반환합니다. 다른 모든 경우 0을 반환합니다. 이 함수는 항상 성공합니다.

int PyType_CheckExact(PyObject *o)

객체 o가 형 객체이지만, 표준형 객체의 서브 형이 아니면 0이 아닌 값을 반환합니다. 다른 모든 경우 0을 반환합니다. 이 함수는 항상 성공합니다.

unsigned int PyType_ClearCache()

Part of the Stable ABI.

내부 조회 캐시를 지웁니다. 현재의 버전 태그를 반환합니다.

unsigned long PyType_GetFlags(PyTypeObject *type)

Part of the Stable ABI.

Return the tp_flags member of type. This function is primarily meant for use with Py_LIMITED_API; the individual flag bits are guaranteed to be stable across Python releases, but access to tp_flags itself is not part of the limited API.

Added in version 3.2.

버전 3.4에서 변경: 반환형은 이제 long이 아니라 unsigned long입니다.

PyObject *PyType_GetDict(PyTypeObject *type)

Return the type object’s internal namespace, which is otherwise only exposed via a read-only proxy (cls.__dict__). This is a replacement for accessing tp_dict directly. The returned dictionary must be treated as read-only.

This function is meant for specific embedding and language-binding cases, where direct access to the dict is necessary and indirect access (e.g. via the proxy or PyObject_GetAttr()) isn’t adequate.

Extension modules should continue to use tp_dict, directly or indirectly, when setting up their own types.

Added in version 3.12.

void PyType_Modified(PyTypeObject *type)

Part of the Stable ABI.

형과 그것의 모든 서브 형에 대한 내부 검색 캐시를 무효로 합니다. 형의 어트리뷰트나 베이스 클래스를 수동으로 수정한 후에는 이 함수를 호출해야 합니다.

int PyType_AddWatcher(PyType_WatchCallback callback)

Register callback as a type watcher. Return a non-negative integer ID which must be passed to future calls to PyType_Watch(). In case of error (e.g. no more watcher IDs available), return -1 and set an exception.

Added in version 3.12.

int PyType_ClearWatcher(int watcher_id)

Clear watcher identified by watcher_id (previously returned from PyType_AddWatcher()). Return 0 on success, -1 on error (e.g. if watcher_id was never registered.)

An extension should never call PyType_ClearWatcher with a watcher_id that was not returned to it by a previous call to PyType_AddWatcher().

Added in version 3.12.

int PyType_Watch(int watcher_id, PyObject *type)

Mark type as watched. The callback granted watcher_id by PyType_AddWatcher() will be called whenever PyType_Modified() reports a change to type. (The callback may be called only once for a series of consecutive modifications to type, if _PyType_Lookup() is not called on type between the modifications; this is an implementation detail and subject to change.)

An extension should never call PyType_Watch with a watcher_id that was not returned to it by a previous call to PyType_AddWatcher().

Added in version 3.12.

typedef int (*PyType_WatchCallback)(PyObject *type)

Type of a type-watcher callback function.

The callback must not modify type or cause PyType_Modified() to be called on type or any type in its MRO; violating this rule could cause infinite recursion.

Added in version 3.12.

int PyType_HasFeature(PyTypeObject *o, int feature)

형 객체 o가 기능 feature를 설정하면 0이 아닌 값을 반환합니다. 형 기능은 단일 비트 플래그로 표시됩니다.

int PyType_IS_GC(PyTypeObject *o)

Return true if the type object includes support for the cycle detector; this tests the type flag Py_TPFLAGS_HAVE_GC.

int PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)

Part of the Stable ABI.

a가 b의 서브 형이면 참을 반환합니다.

This function only checks for actual subtypes, which means that __subclasscheck__() is not called on b. Call PyObject_IsSubclass() to do the same check that issubclass() would do.

PyObject *PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)

Return value: New reference. Part of the Stable ABI.

형 객체의 tp_alloc 슬롯을 위한 일반 처리기. 파이썬의 기본 메모리 할당 메커니즘을 사용하여 새 인스턴스를 할당하고 모든 내용을 NULL로 초기화합니다.

PyObject *PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)

Return value: New reference. Part of the Stable ABI.

형 객체의 tp_new 슬롯을 위한 일반 처리기. 형의 tp_alloc 슬롯을 사용하여 새 인스턴스를 만듭니다.

int PyType_Ready(PyTypeObject *type)

Part of the Stable ABI.

형 개체를 마무리합니다. 초기화를 완료하려면 모든 형 객체에 대해 이 메서드를 호출해야 합니다. 이 함수는 형의 베이스 클래스에서 상속된 슬롯을 추가합니다. 성공 시 0을 반환하고, 오류 시 -1을 반환하고 예외를 설정합니다.

참고

If some of the base classes implements the GC protocol and the provided type does not include the Py_TPFLAGS_HAVE_GC in its flags, then the GC protocol will be automatically implemented from its parents. On the contrary, if the type being created does include Py_TPFLAGS_HAVE_GC in its flags then it must implement the GC protocol itself by at least implementing the tp_traverse handle.

PyObject *PyType_GetName(PyTypeObject *type)

Return value: New reference. Part of the Stable ABI since version 3.11.

Return the type’s name. Equivalent to getting the type’s __name__ attribute.

Added in version 3.11.

PyObject *PyType_GetQualName(PyTypeObject *type)

Return value: New reference. Part of the Stable ABI since version 3.11.

Return the type’s qualified name. Equivalent to getting the type’s __qualname__ attribute.

Added in version 3.11.

PyObject *PyType_GetFullyQualifiedName(PyTypeObject *type)

Part of the Stable ABI since version 3.13.

Return the type’s fully qualified name. Equivalent to f"{type.__module__}.{type.__qualname__}", or type.__qualname__ if type.__module__ is not a string or is equal to "builtins".

Added in version 3.13.

PyObject *PyType_GetModuleName(PyTypeObject *type)

Part of the Stable ABI since version 3.13.

Return the type’s module name. Equivalent to getting the type.__module__ attribute.

Added in version 3.13.

void *PyType_GetSlot(PyTypeObject *type, int slot)

Part of the Stable ABI since version 3.4.

지정된 슬롯에 저장된 함수 포인터를 반환합니다. 결과가 NULL이면, 슬롯이 NULL이거나 함수가 유효하지 않은 매개 변수로 호출되었음을 나타냅니다. 호출자는 일반적으로 결과 포인터를 적절한 함수 형으로 캐스팅합니다.

slot 인자의 가능한 값은 PyType_Slot.slot을 참조하십시오.

Added in version 3.4.

버전 3.10에서 변경: PyType_GetSlot() can now accept all types. Previously, it was limited to heap types.

PyObject *PyType_GetModule(PyTypeObject *type)

Part of the Stable ABI since version 3.10.

PyType_FromModuleAndSpec()를 사용하여 형을 만들 때 지정된 형과 관련된 모듈 객체를 반환합니다.

주어진 형과 연관된 모듈이 없으면, TypeError를 설정하고 NULL을 반환합니다.

This function is usually used to get the module in which a method is defined. Note that in such a method, PyType_GetModule(Py_TYPE(self)) may not return the intended result. Py_TYPE(self) may be a subclass of the intended class, and subclasses are not necessarily defined in the same module as their superclass. See PyCMethod to get the class that defines the method. See PyType_GetModuleByDef() for cases when PyCMethod cannot be used.

Added in version 3.9.

void *PyType_GetModuleState(PyTypeObject *type)

Part of the Stable ABI since version 3.10.

주어진 형과 관련된 모듈 객체의 상태를 반환합니다. PyType_GetModule() 결과에 PyModule_GetState()를 호출하는 바로 가기입니다.

주어진 형과 연관된 모듈이 없으면, TypeError를 설정하고 NULL을 반환합니다.

type에 연관된 모듈이 있지만, 상태가 NULL이면, 예외를 설정하지 않고 NULL을 반환합니다.

Added in version 3.9.

PyObject *PyType_GetModuleByDef(PyTypeObject *type, struct PyModuleDef *def)

Part of the Stable ABI since version 3.13.

Find the first superclass whose module was created from the given PyModuleDef def, and return that module.

If no module is found, raises a TypeError and returns NULL.

This function is intended to be used together with PyModule_GetState() to get module state from slot methods (such as tp_init or nb_add) and other places where a method’s defining class cannot be passed using the PyCMethod calling convention.

Added in version 3.11.

int PyType_GetBaseByToken(PyTypeObject *type, void *token, PyTypeObject **result)

Part of the Stable ABI since version 3.14.

Find the first superclass in type’s method resolution order whose Py_tp_token token is equal to the given one.

If found, set *result to a new strong reference to it and return 1.

If not found, set *result to NULL and return 0.

On error, set *result to NULL and return -1 with an exception set.

The result argument may be NULL, in which case *result is not set. Use this if you need only the return value.

The token argument may not be NULL.

Added in version 3.14.

int PyUnstable_Type_AssignVersionTag(PyTypeObject *type)

This is Unstable API. It may change without warning in minor releases.

Attempt to assign a version tag to the given type.

Returns 1 if the type already had a valid version tag or a new one was assigned, or 0 if a new tag could not be assigned.

Added in version 3.12.

힙에 할당된 형 만들기

다음 함수와 구조체는 힙 형을 만드는 데 사용됩니다.

PyObject *PyType_FromMetaclass(PyTypeObject *metaclass, PyObject *module, PyType_Spec *spec, PyObject *bases)

Part of the Stable ABI since version 3.12.

Create and return a heap type from the spec (see Py_TPFLAGS_HEAPTYPE).

The metaclass metaclass is used to construct the resulting type object. When metaclass is NULL, the metaclass is derived from bases (or Py_tp_base[s] slots if bases is NULL, see below).

Metaclasses that override tp_new are not supported, except if tp_new is NULL. (For backwards compatibility, other PyType_From* functions allow such metaclasses. They ignore tp_new, which may result in incomplete initialization. This is deprecated and in Python 3.14+ such metaclasses will not be supported.)

The bases argument can be used to specify base classes; it can either be only one class or a tuple of classes. If bases is NULL, the Py_tp_bases slot is used instead. If that also is NULL, the Py_tp_base slot is used instead. If that also is NULL, the new type derives from object.

The module argument can be used to record the module in which the new class is defined. It must be a module object or NULL. If not NULL, the module is associated with the new type and can later be retrieved with PyType_GetModule(). The associated module is not inherited by subclasses; it must be specified for each class individually.

이 함수는 새로운 형에 PyType_Ready()를 호출합니다.

Note that this function does not fully match the behavior of calling type() or using the class statement. With user-provided base types or metaclasses, prefer calling type (or the metaclass) over PyType_From* functions. Specifically:

__new__() is not called on the new class (and it must be set to type.__new__).

__init__() is not called on the new class.

__init_subclass__() is not called on any bases.

__set_name__() is not called on new descriptors.

Added in version 3.12.

PyObject *PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)

Return value: New reference. Part of the Stable ABI since version 3.10.

Equivalent to PyType_FromMetaclass(NULL, module, spec, bases).

Added in version 3.9.

버전 3.10에서 변경: The function now accepts a single class as the bases argument and NULL as the tp_doc slot.

버전 3.12에서 변경: The function now finds and uses a metaclass corresponding to the provided base classes. Previously, only type instances were returned.

The tp_new of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides tp_new is deprecated.

버전 3.14에서 변경: Creating classes whose metaclass overrides tp_new is no longer allowed.

PyObject *PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases)

Return value: New reference. Part of the Stable ABI since version 3.3.

Equivalent to PyType_FromMetaclass(NULL, NULL, spec, bases).

Added in version 3.3.

버전 3.12에서 변경: The function now finds and uses a metaclass corresponding to the provided base classes. Previously, only type instances were returned.

The tp_new of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides tp_new is deprecated.

버전 3.14에서 변경: Creating classes whose metaclass overrides tp_new is no longer allowed.

PyObject *PyType_FromSpec(PyType_Spec *spec)

Return value: New reference. Part of the Stable ABI.

Equivalent to PyType_FromMetaclass(NULL, NULL, spec, NULL).

버전 3.12에서 변경: The function now finds and uses a metaclass corresponding to the base classes provided in Py_tp_base[s] slots. Previously, only type instances were returned.

The tp_new of the metaclass is ignored. which may result in incomplete initialization. Creating classes whose metaclass overrides tp_new is deprecated.

버전 3.14에서 변경: Creating classes whose metaclass overrides tp_new is no longer allowed.

int PyType_Freeze(PyTypeObject *type)

Part of the Stable ABI since version 3.14.

Make a type immutable: set the Py_TPFLAGS_IMMUTABLETYPE flag.

All base classes of type must be immutable.

On success, return 0. On error, set an exception and return -1.

The type must not be used before it’s made immutable. For example, type instances must not be created before the type is made immutable.

Added in version 3.14.

type PyType_Spec

Part of the Stable ABI (including all members).

형의 행동을 정의하는 구조체.

const char *name

형의 이름, PyTypeObject.tp_name을 설정하는 데 사용됩니다.

int basicsize

If positive, specifies the size of the instance in bytes. It is used to set PyTypeObject.tp_basicsize.

If zero, specifies that tp_basicsize should be inherited.

If negative, the absolute value specifies how much space instances of the class need in addition to the superclass. Use PyObject_GetTypeData() to get a pointer to subclass-specific memory reserved this way.

버전 3.12에서 변경: Previously, this field could not be negative.

int itemsize

Size of one element of a variable-size type, in bytes. Used to set PyTypeObject.tp_itemsize. See tp_itemsize documentation for caveats.

If zero, tp_itemsize is inherited. Extending arbitrary variable-sized classes is dangerous, since some types use a fixed offset for variable-sized memory, which can then overlap fixed-sized memory used by a subclass. To help prevent mistakes, inheriting itemsize is only possible in the following situations:

The base is not variable-sized (its tp_itemsize).

The requested PyType_Spec.basicsize is positive, suggesting that the memory layout of the base class is known.

The requested PyType_Spec.basicsize is zero, suggesting that the subclass does not access the instance’s memory directly.

With the Py_TPFLAGS_ITEMS_AT_END flag.

unsigned int flags

형 플래그, PyTypeObject.tp_flags를 설정하는 데 사용됩니다.

Py_TPFLAGS_HEAPTYPE 플래그가 설정되어 있지 않으면, PyType_FromSpecWithBases() 가 자동으로 플래그를 설정합니다.

PyType_Slot *slots

PyType_Slot 구조체의 배열. 특수 슬롯값 {0, NULL}에 의해 종료됩니다.

Each slot ID should be specified at most once.

type PyType_Slot

Part of the Stable ABI (including all members).

형의 선택적 기능을 정의하는 구조체, 슬롯 ID와 값 포인터를 포함합니다.

int slot

슬롯 ID.

슬롯 ID는 구조체 PyTypeObject, PyNumberMethods, PySequenceMethods, PyMappingMethods 및 PyAsyncMethods 의 필드 이름에 Py_ 접두사를 붙인 이름을 사용합니다. 예를 들어, :

PyTypeObject.tp_dealloc을 설정하는 Py_tp_dealloc

PyNumberMethods.nb_add를 설정하는 Py_nb_add

PySequenceMethods.sq_length를 설정하는 Py_sq_length

An additional slot is supported that does not correspond to a PyTypeObject struct field:

Py_tp_token

The following “offset” fields cannot be set using PyType_Slot:

tp_weaklistoffset (use Py_TPFLAGS_MANAGED_WEAKREF instead if possible)

tp_dictoffset (use Py_TPFLAGS_MANAGED_DICT instead if possible)

tp_vectorcall_offset (use "__vectorcalloffset__" in PyMemberDef)

If it is not possible to switch to a MANAGED flag (for example, for vectorcall or to support Python older than 3.12), specify the offset in Py_tp_members. See PyMemberDef documentation for details.

The following internal fields cannot be set at all when creating a heap type:

tp_dict, tp_mro, tp_cache, tp_subclasses, and tp_weaklist.

Setting Py_tp_bases or Py_tp_base may be problematic on some platforms. To avoid issues, use the bases argument of PyType_FromSpecWithBases() instead.

버전 3.9에서 변경: Slots in PyBufferProcs may be set in the unlimited API.

버전 3.11에서 변경: bf_getbuffer and bf_releasebuffer are now available under the limited API.

버전 3.14에서 변경: The field tp_vectorcall can now set using Py_tp_vectorcall. See the field’s documentation for details.

void *pfunc

슬롯의 원하는 값입니다. 대부분 이것은 함수에 대한 포인터입니다.

pfunc values may not be NULL, except for the following slots:

Py_tp_doc

Py_tp_token (for clarity, prefer Py_TP_USE_SPEC rather than NULL)

Py_tp_token

A slot that records a static memory layout ID for a class.

If the PyType_Spec of the class is statically allocated, the token can be set to the spec using the special value Py_TP_USE_SPEC:

static PyType_Slot foo_slots[] = {
   {Py_tp_token, Py_TP_USE_SPEC},

It can also be set to an arbitrary pointer, but you must ensure that:

The pointer outlives the class, so it’s not reused for something else while the class exists.

It “belongs” to the extension module where the class lives, so it will not clash with other extensions.

Use PyType_GetBaseByToken() to check if a class’s superclass has a given token – that is, check whether the memory layout is compatible.

To get the token for a given class (without considering superclasses), use PyType_GetSlot() with Py_tp_token.

Added in version 3.14.

Py_TP_USE_SPEC

Used as a value with Py_tp_token to set the token to the class’s PyType_Spec. Expands to NULL.

Added in version 3.14.

None 객체

Note that the PyTypeObject for None is not directly exposed in the Python/C API. Since None is a singleton, testing for object identity (using == in C) is sufficient. There is no PyNone_Check() function for the same reason.

PyObject *Py_None

The Python None object, denoting lack of value. This object has no methods and is immortal.

버전 3.12에서 변경: Py_None is immortal.

Py_RETURN_NONE

Return Py_None from a function.

정수 객체

모든 정수는 임의의 크기의 “long” 정수 객체로 구현됩니다.

에러 시, 대부분의 PyLong_As* API는 숫자와 구별할 수 없는 (return type)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

type PyLongObject

Part of the Limited API (as an opaque struct).

이 PyObject의 서브 형은 파이썬 정수 객체를 나타냅니다.

PyTypeObject PyLong_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 정수 형을 나타냅니다. 이것은 파이썬 계층의 int와 같은 객체입니다.

int PyLong_Check(PyObject *p)

인자가 PyLongObject이나 PyLongObject의 서브 형이면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyLong_CheckExact(PyObject *p)

인자가 PyLongObject 이지만 PyLongObject의 서브 형이 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyLong_FromLong(long v)

Return value: New reference. Part of the Stable ABI.

v로부터 새 PyLongObject 객체를 반환하거나, 실패하면 NULL을 반환합니다.

The current implementation keeps an array of integer objects for all integers between -5 and 256. When you create an int in that range you actually just get back a reference to the existing object.

PyObject *PyLong_FromUnsignedLong(unsigned long v)

Return value: New reference. Part of the Stable ABI.

Return a new PyLongObject object from a C unsigned long, or NULL on failure.

PyObject *PyLong_FromSsize_t(Py_ssize_t v)

Return value: New reference. Part of the Stable ABI.

C Py_ssize_t로부터 새 PyLongObject 객체를 반환하거나, 실패하면 NULL을 반환합니다.

PyObject *PyLong_FromSize_t(size_t v)

Return value: New reference. Part of the Stable ABI.

C size_t로부터 새 PyLongObject 객체를 반환하거나, 실패하면 NULL을 반환합니다.

PyObject *PyLong_FromLongLong(long long v)

Return value: New reference. Part of the Stable ABI.

Return a new PyLongObject object from a C long long, or NULL on failure.

PyObject *PyLong_FromInt32(int32_t value)

PyObject *PyLong_FromInt64(int64_t value)

Part of the Stable ABI since version 3.14.

Return a new PyLongObject object from a signed C int32_t or int64_t, or NULL with an exception set on failure.

Added in version 3.14.

PyObject *PyLong_FromUnsignedLongLong(unsigned long long v)

Return value: New reference. Part of the Stable ABI.

Return a new PyLongObject object from a C unsigned long long, or NULL on failure.

PyObject *PyLong_FromUInt32(uint32_t value)

PyObject *PyLong_FromUInt64(uint64_t value)

Part of the Stable ABI since version 3.14.

Return a new PyLongObject object from an unsigned C uint32_t or uint64_t, or NULL with an exception set on failure.

Added in version 3.14.

PyObject *PyLong_FromDouble(double v)

Return value: New reference. Part of the Stable ABI.

v의 정수 부분으로부터 새 PyLongObject 객체를 반환하거나, 실패하면 NULL을 반환합니다.

PyObject *PyLong_FromString(const char *str, char **pend, int base)

Return value: New reference. Part of the Stable ABI.

Return a new PyLongObject based on the string value in str, which is interpreted according to the radix in base, or NULL on failure. If pend is non-NULL, *pend will point to the end of str on success or to the first character that could not be processed on error. If base is 0, str is interpreted using the 정수 리터럴 definition; in this case, leading zeros in a non-zero decimal number raises a ValueError. If base is not 0, it must be between 2 and 36, inclusive. Leading and trailing whitespace and single underscores after a base specifier and between digits are ignored. If there are no digits or str is not NULL-terminated following the digits and trailing whitespace, ValueError will be raised.

더 보기

PyLong_AsNativeBytes() and PyLong_FromNativeBytes() functions can be used to convert a PyLongObject to/from an array of bytes in base 256.

PyObject *PyLong_FromUnicodeObject(PyObject *u, int base)

Return value: New reference.

문자열 u에 있는 유니코드 숫자의 시퀀스를 파이썬 정숫값으로 변환합니다.

Added in version 3.3.

PyObject *PyLong_FromVoidPtr(void *p)

Return value: New reference. Part of the Stable ABI.

포인터 p로부터 파이썬 정수를 만듭니다. 포인터 값은 PyLong_AsVoidPtr()를 사용하여 결괏값에서 조회할 수 있습니다.

PyObject *PyLong_FromNativeBytes(const void *buffer, size_t n_bytes, int flags)

Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as a two’s-complement signed number.

flags are as for PyLong_AsNativeBytes(). Passing -1 will select the native endian that CPython was compiled with and assume that the most-significant bit is a sign bit. Passing Py_ASNATIVEBYTES_UNSIGNED_BUFFER will produce the same result as calling PyLong_FromUnsignedNativeBytes(). Other flags are ignored.

Added in version 3.13.

PyObject *PyLong_FromUnsignedNativeBytes(const void *buffer, size_t n_bytes, int flags)

Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as an unsigned number.

flags are as for PyLong_AsNativeBytes(). Passing -1 will select the native endian that CPython was compiled with and assume that the most-significant bit is not a sign bit. Flags other than endian are ignored.

Added in version 3.13.

long PyLong_AsLong(PyObject *obj)

Part of the Stable ABI.

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long.

에러 시 -1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

long PyLong_AS_LONG(PyObject *obj)

A soft deprecated alias. Exactly equivalent to the preferred PyLong_AsLong. In particular, it can fail with OverflowError or another exception.

버전 3.14부터 폐지됨: The function is soft deprecated.

int PyLong_AsInt(PyObject *obj)

Part of the Stable ABI since version 3.13.

Similar to PyLong_AsLong(), but store the result in a C int instead of a C long.

Added in version 3.13.

long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)

Part of the Stable ABI.

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than LONG_MAX or less than LONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

에러 시 -1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

long long PyLong_AsLongLong(PyObject *obj)

Part of the Stable ABI.

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long long.

에러 시 -1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)

Part of the Stable ABI.

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than LLONG_MAX or less than LLONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

에러 시 -1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

Added in version 3.2.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)

Part of the Stable ABI.

pylong의 C Py_ssize_t 표현을 반환합니다. pylong은 PyLongObject의 인스턴스여야 합니다.

pylong의 값이 Py_ssize_t의 범위를 벗어나면 OverflowError를 발생시킵니다.

에러 시 -1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

unsigned long PyLong_AsUnsignedLong(PyObject *pylong)

Part of the Stable ABI.

Return a C unsigned long representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a unsigned long.

에러 시 (unsigned long)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

size_t PyLong_AsSize_t(PyObject *pylong)

Part of the Stable ABI.

pylong의 C size_t 표현을 반환합니다. pylong은 PyLongObject의 인스턴스여야 합니다.

pylong의 값이 size_t의 범위를 벗어나면 OverflowError를 발생시킵니다.

에러 시 (size_t)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)

Part of the Stable ABI.

Return a C unsigned long long representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for an unsigned long long.

에러 시 (unsigned long long)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.1에서 변경: 음의 pylong는 이제 TypeError가 아니라 OverflowError를 발생시킵니다.

unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)

Part of the Stable ABI.

Return a C unsigned long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long, return the reduction of that value modulo ULONG_MAX + 1.

에러 시 (unsigned long)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)

Part of the Stable ABI.

Return a C unsigned long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long long, return the reduction of that value modulo ULLONG_MAX + 1.

에러 시 (unsigned long long)-1을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

버전 3.8에서 변경: Use __index__() if available.

버전 3.10에서 변경: This function will no longer use __int__().

int PyLong_AsInt32(PyObject *obj, int32_t *value)

int PyLong_AsInt64(PyObject *obj, int64_t *value)

Part of the Stable ABI since version 3.14.

Set *value to a signed C int32_t or int64_t representation of obj.

If the obj value is out of range, raise an OverflowError.

Set *value and return 0 on success. Set an exception and return -1 on error.

value must not be NULL.

Added in version 3.14.

int PyLong_AsUInt32(PyObject *obj, uint32_t *value)

int PyLong_AsUInt64(PyObject *obj, uint64_t *value)

Part of the Stable ABI since version 3.14.

Set *value to an unsigned C uint32_t or uint64_t representation of obj.

If obj is not an instance of PyLongObject, first call its __index__() method (if present) to convert it to a PyLongObject.

If obj is negative, raise a ValueError.

If the obj value is out of range, raise an OverflowError.

Set *value and return 0 on success. Set an exception and return -1 on error.

value must not be NULL.

Added in version 3.14.

double PyLong_AsDouble(PyObject *pylong)

Part of the Stable ABI.

Return a C double representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a double.

에러 시 -1.0을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

void *PyLong_AsVoidPtr(PyObject *pylong)

Part of the Stable ABI.

Convert a Python integer pylong to a C void pointer. If pylong cannot be converted, an OverflowError will be raised. This is only assured to produce a usable void pointer for values created with PyLong_FromVoidPtr().

에러 시 NULL을 반환합니다. 모호성을 제거하려면 PyErr_Occurred()를 사용하십시오.

Py_ssize_t PyLong_AsNativeBytes(PyObject *pylong, void *buffer, Py_ssize_t n_bytes, int flags)

Copy the Python integer value pylong to a native buffer of size n_bytes. The flags can be set to -1 to behave similarly to a C cast, or to values documented below to control the behavior.

Returns -1 with an exception raised on error. This may happen if pylong cannot be interpreted as an integer, or if pylong was negative and the Py_ASNATIVEBYTES_REJECT_NEGATIVE flag was set.

Otherwise, returns the number of bytes required to store the value. If this is equal to or less than n_bytes, the entire value was copied. All n_bytes of the buffer are written: large buffers are padded with zeroes.

If the returned value is greater than than n_bytes, the value was truncated: as many of the lowest bits of the value as could fit are written, and the higher bits are ignored. This matches the typical behavior of a C-style downcast.

참고

Overflow is not considered an error. If the returned value is larger than n_bytes, most significant bits were discarded.

0 will never be returned.

Values are always copied as two’s-complement.

Usage example:

int32_t value;
Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, &value, sizeof(value), -1);
if (bytes < 0) {
    // Failed. A Python exception was set with the reason.
    return NULL;
}
else if (bytes <= (Py_ssize_t)sizeof(value)) {
    // Success!
}
else {
    // Overflow occurred, but 'value' contains the truncated
    // lowest bits of pylong.
}

Passing zero to n_bytes will return the size of a buffer that would be large enough to hold the value. This may be larger than technically necessary, but not unreasonably so. If n_bytes=0, buffer may be NULL.

참고

Passing n_bytes=0 to this function is not an accurate way to determine the bit length of the value.

To get at the entire Python value of an unknown size, the function can be called twice: first to determine the buffer size, then to fill it:

// Ask how much space we need.
Py_ssize_t expected = PyLong_AsNativeBytes(pylong, NULL, 0, -1);
if (expected < 0) {
    // Failed. A Python exception was set with the reason.
    return NULL;
}
assert(expected != 0);  // Impossible per the API definition.
uint8_t *bignum = malloc(expected);
if (!bignum) {
    PyErr_SetString(PyExc_MemoryError, "bignum malloc failed.");
    return NULL;
}
// Safely get the entire value.
Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, bignum, expected, -1);
if (bytes < 0) {  // Exception has been set.
    free(bignum);
    return NULL;
}
else if (bytes > expected) {  // This should not be possible.
    PyErr_SetString(PyExc_RuntimeError,
        "Unexpected bignum truncation after a size check.");
    free(bignum);
    return NULL;
}
// The expected success given the above pre-check.
// ... use bignum ...
free(bignum);

flags is either -1 (Py_ASNATIVEBYTES_DEFAULTS) to select defaults that behave most like a C cast, or a combination of the other flags in the table below. Note that -1 cannot be combined with other flags.

Currently, -1 corresponds to Py_ASNATIVEBYTES_NATIVE_ENDIAN | Py_ASNATIVEBYTES_UNSIGNED_BUFFER.

Flag

Value

Py_ASNATIVEBYTES_DEFAULTS

-1

Py_ASNATIVEBYTES_BIG_ENDIAN

0

Py_ASNATIVEBYTES_LITTLE_ENDIAN

1

Py_ASNATIVEBYTES_NATIVE_ENDIAN

3

Py_ASNATIVEBYTES_UNSIGNED_BUFFER

4

Py_ASNATIVEBYTES_REJECT_NEGATIVE

8

Py_ASNATIVEBYTES_ALLOW_INDEX

16

Specifying Py_ASNATIVEBYTES_NATIVE_ENDIAN will override any other endian flags. Passing 2 is reserved.

By default, sufficient buffer will be requested to include a sign bit. For example, when converting 128 with n_bytes=1, the function will return 2 (or more) in order to store a zero sign bit.

If Py_ASNATIVEBYTES_UNSIGNED_BUFFER is specified, a zero sign bit will be omitted from size calculations. This allows, for example, 128 to fit in a single-byte buffer. If the destination buffer is later treated as signed, a positive input value may become negative. Note that the flag does not affect handling of negative values: for those, space for a sign bit is always requested.

Specifying Py_ASNATIVEBYTES_REJECT_NEGATIVE causes an exception to be set if pylong is negative. Without this flag, negative values will be copied provided there is enough space for at least one sign bit, regardless of whether Py_ASNATIVEBYTES_UNSIGNED_BUFFER was specified.

If Py_ASNATIVEBYTES_ALLOW_INDEX is specified and a non-integer value is passed, its __index__() method will be called first. This may result in Python code executing and other threads being allowed to run, which could cause changes to other objects or values in use. When flags is -1, this option is not set, and non-integer values will raise TypeError.

참고

With the default flags (-1, or UNSIGNED_BUFFER without REJECT_NEGATIVE), multiple Python integers can map to a single value without overflow. For example, both 255 and -1 fit a single-byte buffer and set all its bits. This matches typical C cast behavior.

Added in version 3.13.

int PyLong_GetSign(PyObject *obj, int *sign)

Get the sign of the integer object obj.

On success, set *sign to the integer sign (0, -1 or +1 for zero, negative or positive integer, respectively) and return 0.

On failure, return -1 with an exception set. This function always succeeds if obj is a PyLongObject or its subtype.

Added in version 3.14.

int PyLong_IsPositive(PyObject *obj)

Check if the integer object obj is positive (obj > 0).

If obj is an instance of PyLongObject or its subtype, return 1 when it’s positive and 0 otherwise. Else set an exception and return -1.

Added in version 3.14.

int PyLong_IsNegative(PyObject *obj)

Check if the integer object obj is negative (obj < 0).

If obj is an instance of PyLongObject or its subtype, return 1 when it’s negative and 0 otherwise. Else set an exception and return -1.

Added in version 3.14.

int PyLong_IsZero(PyObject *obj)

Check if the integer object obj is zero.

If obj is an instance of PyLongObject or its subtype, return 1 when it’s zero and 0 otherwise. Else set an exception and return -1.

Added in version 3.14.

PyObject *PyLong_GetInfo(void)

Part of the Stable ABI.

On success, return a read only named tuple, that holds information about Python’s internal representation of integers. See sys.int_info for description of individual fields.

On failure, return NULL with an exception set.

Added in version 3.1.

int PyUnstable_Long_IsCompact(const PyLongObject *op)

This is Unstable API. It may change without warning in minor releases.

Return 1 if op is compact, 0 otherwise.

This function makes it possible for performance-critical code to implement a “fast path” for small integers. For compact values use PyUnstable_Long_CompactValue(); for others fall back to a PyLong_As* function or PyLong_AsNativeBytes().

The speedup is expected to be negligible for most users.

Exactly what values are considered compact is an implementation detail and is subject to change.

Added in version 3.12.

Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject *op)

This is Unstable API. It may change without warning in minor releases.

If op is compact, as determined by PyUnstable_Long_IsCompact(), return its value.

Otherwise, the return value is undefined.

Added in version 3.12.

불리언 객체

Booleans in Python are implemented as a subclass of integers. There are only two booleans, Py_False and Py_True. As such, the normal creation and deletion functions don’t apply to booleans. The following macros are available, however.

PyTypeObject PyBool_Type

Part of the Stable ABI.

This instance of PyTypeObject represents the Python boolean type; it is the same object as bool in the Python layer.

int PyBool_Check(PyObject *o)

o가 PyBool_Type 형이면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

PyObject *Py_False

The Python False object. This object has no methods and is immortal.

버전 3.12에서 변경: Py_False is immortal.

PyObject *Py_True

The Python True object. This object has no methods and is immortal.

버전 3.12에서 변경: Py_True is immortal.

Py_RETURN_FALSE

Return Py_False from a function.

Py_RETURN_TRUE

Return Py_True from a function.

PyObject *PyBool_FromLong(long v)

Return value: New reference. Part of the Stable ABI.

Return Py_True or Py_False, depending on the truth value of v.

Floating-Point Objects

type PyFloatObject

This subtype of PyObject represents a Python floating-point object.

PyTypeObject PyFloat_Type

Part of the Stable ABI.

This instance of PyTypeObject represents the Python floating-point type. This is the same object as float in the Python layer.

int PyFloat_Check(PyObject *p)

인자가 PyFloatObject 나 PyFloatObject의 서브 형이면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyFloat_CheckExact(PyObject *p)

인자가 PyFloatObject이지만 PyFloatObject의 서브 형은 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyFloat_FromString(PyObject *str)

Return value: New reference. Part of the Stable ABI.

str의 문자열 값을 기반으로 PyFloatObject 객체를 만들거나, 실패하면 NULL.

PyObject *PyFloat_FromDouble(double v)

Return value: New reference. Part of the Stable ABI.

v로부터 PyFloatObject 객체를 만들거나, 실패하면 NULL.

double PyFloat_AsDouble(PyObject *pyfloat)

Part of the Stable ABI.

Return a C double representation of the contents of pyfloat. If pyfloat is not a Python floating-point object but has a __float__() method, this method will first be called to convert pyfloat into a float. If __float__() is not defined then it falls back to __index__(). This method returns -1.0 upon failure, so one should call PyErr_Occurred() to check for errors.

버전 3.8에서 변경: Use __index__() if available.

double PyFloat_AS_DOUBLE(PyObject *pyfloat)

Return a C double representation of the contents of pyfloat, but without error checking.

PyObject *PyFloat_GetInfo(void)

Return value: New reference. Part of the Stable ABI.

float의 정밀도, 최솟값, 최댓값에 관한 정보를 포함한 structseq 인스턴스를 돌려줍니다. 헤더 파일 float.h를 감싸는 얇은 래퍼입니다.

double PyFloat_GetMax()

Part of the Stable ABI.

Return the maximum representable finite float DBL_MAX as C double.

double PyFloat_GetMin()

Part of the Stable ABI.

Return the minimum normalized positive float DBL_MIN as C double.

Pack and Unpack functions

The pack and unpack functions provide an efficient platform-independent way to store floating-point values as byte strings. The Pack routines produce a bytes string from a C double, and the Unpack routines produce a C double from such a bytes string. The suffix (2, 4 or 8) specifies the number of bytes in the bytes string.

On platforms that appear to use IEEE 754 formats these functions work by copying bits. On other platforms, the 2-byte format is identical to the IEEE 754 binary16 half-precision format, the 4-byte format (32-bit) is identical to the IEEE 754 binary32 single precision format, and the 8-byte format to the IEEE 754 binary64 double precision format, although the packing of INFs and NaNs (if such things exist on the platform) isn’t handled correctly, and attempting to unpack a bytes string containing an IEEE INF or NaN will raise an exception.

On non-IEEE platforms with more precision, or larger dynamic range, than IEEE 754 supports, not all values can be packed; on non-IEEE platforms with less precision, or smaller dynamic range, not all values can be unpacked. What happens in such cases is partly accidental (alas).

Added in version 3.11.

Pack functions

The pack routines write 2, 4 or 8 bytes, starting at p. le is an int argument, non-zero if you want the bytes string in little-endian format (exponent last, at p+1, p+3, or p+6 p+7), zero if you want big-endian format (exponent first, at p). The PY_BIG_ENDIAN constant can be used to use the native endian: it is equal to 1 on big endian processor, or 0 on little endian processor.

Return value: 0 if all is OK, -1 if error (and an exception is set, most likely OverflowError).

There are two problems on non-IEEE platforms:

What this does is undefined if x is a NaN or infinity.

-0.0 and +0.0 produce the same bytes string.

int PyFloat_Pack2(double x, unsigned char *p, int le)

Pack a C double as the IEEE 754 binary16 half-precision format.

int PyFloat_Pack4(double x, unsigned char *p, int le)

Pack a C double as the IEEE 754 binary32 single precision format.

int PyFloat_Pack8(double x, unsigned char *p, int le)

Pack a C double as the IEEE 754 binary64 double precision format.

Unpack functions

The unpack routines read 2, 4 or 8 bytes, starting at p. le is an int argument, non-zero if the bytes string is in little-endian format (exponent last, at p+1, p+3 or p+6 and p+7), zero if big-endian (exponent first, at p). The PY_BIG_ENDIAN constant can be used to use the native endian: it is equal to 1 on big endian processor, or 0 on little endian processor.

Return value: The unpacked double. On error, this is -1.0 and PyErr_Occurred() is true (and an exception is set, most likely OverflowError).

Note that on a non-IEEE platform this will refuse to unpack a bytes string that represents a NaN or infinity.

double PyFloat_Unpack2(const unsigned char *p, int le)

Unpack the IEEE 754 binary16 half-precision format as a C double.

double PyFloat_Unpack4(const unsigned char *p, int le)

Unpack the IEEE 754 binary32 single precision format as a C double.

double PyFloat_Unpack8(const unsigned char *p, int le)

Unpack the IEEE 754 binary64 double precision format as a C double.

복소수 객체

파이썬의 복소수 객체는 C API에서 볼 때 두 개의 다른 형으로 구현됩니다: 하나는 파이썬 프로그램에 노출된 파이썬 객체이고, 다른 하나는 실제 복소수 값을 나타내는 C 구조체입니다. API는 두 가지 모두도 작업할 수 있는 함수를 제공합니다.

C 구조체로서의 복소수

매개 변수로 이러한 구조체를 받아들이고 결과로 반환하는 함수는 포인터를 통해 역참조하기보다는 값으로 다룹니다. 이는 API 전체에서 일관됩니다.

type Py_complex

The C structure which corresponds to the value portion of a Python complex number object. Most of the functions for dealing with complex number objects use structures of this type as input or output values, as appropriate.

double real

double imag

The structure is defined as:

typedef struct {
    double real;
    double imag;
} Py_complex;

Py_complex _Py_c_sum(Py_complex left, Py_complex right)

C Py_complex 표현을 사용하여 두 복소수의 합을 반환합니다.

Py_complex _Py_cr_sum(Py_complex left, double right)

Return the sum of a complex number and a real number, using the C Py_complex representation.

Added in version 3.14.

Py_complex _Py_c_diff(Py_complex left, Py_complex right)

C Py_complex 표현을 사용하여 두 복소수의 차이를 반환합니다.

Py_complex _Py_cr_diff(Py_complex left, double right)

Return the difference between a complex number and a real number, using the C Py_complex representation.

Added in version 3.14.

Py_complex _Py_rc_diff(double left, Py_complex right)

Return the difference between a real number and a complex number, using the C Py_complex representation.

Added in version 3.14.

Py_complex _Py_c_neg(Py_complex num)

Return the negation of the complex number num, using the C Py_complex representation.

Py_complex _Py_c_prod(Py_complex left, Py_complex right)

C Py_complex 표현을 사용하여 두 복소수의 곱을 반환합니다.

Py_complex _Py_cr_prod(Py_complex left, double right)

Return the product of a complex number and a real number, using the C Py_complex representation.

Added in version 3.14.

Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor)

C Py_complex 표현을 사용하여 두 복소수의 몫을 반환합니다.

If divisor is null, this method returns zero and sets errno to EDOM.

Py_complex _Py_cr_quot(Py_complex dividend, double divisor)

Return the quotient of a complex number and a real number, using the C Py_complex representation.

If divisor is zero, this method returns zero and sets errno to EDOM.

Added in version 3.14.

Py_complex _Py_rc_quot(double dividend, Py_complex divisor)

Return the quotient of a real number and a complex number, using the C Py_complex representation.

If divisor is zero, this method returns zero and sets errno to EDOM.

Added in version 3.14.

Py_complex _Py_c_pow(Py_complex num, Py_complex exp)

C Py_complex 표현을 사용하여 num의 exp 거듭제곱을 반환합니다.

If num is null and exp is not a positive real number, this method returns zero and sets errno to EDOM.

Set errno to ERANGE on overflows.

파이썬 객체로서의 복소수

type PyComplexObject

파이썬 복소수 객체를 나타내는 PyObject의 서브 형.

PyTypeObject PyComplex_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 복소수 형을 나타냅니다. 파이썬 계층의 complex와 같은 객체입니다.

int PyComplex_Check(PyObject *p)

인자가 PyComplexObject 나 PyComplexObject의 서브 형이면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyComplex_CheckExact(PyObject *p)

인자가 PyComplexObject이지만, PyComplexObject의 서브 유형이 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyComplex_FromCComplex(Py_complex v)

Return value: New reference.

Create a new Python complex number object from a C Py_complex value. Return NULL with an exception set on error.

PyObject *PyComplex_FromDoubles(double real, double imag)

Return value: New reference. Part of the Stable ABI.

Return a new PyComplexObject object from real and imag. Return NULL with an exception set on error.

double PyComplex_RealAsDouble(PyObject *op)

Part of the Stable ABI.

Return the real part of op as a C double.

If op is not a Python complex number object but has a __complex__() method, this method will first be called to convert op to a Python complex number object. If __complex__() is not defined then it falls back to call PyFloat_AsDouble() and returns its result.

Upon failure, this method returns -1.0 with an exception set, so one should call PyErr_Occurred() to check for errors.

버전 3.13에서 변경: Use __complex__() if available.

double PyComplex_ImagAsDouble(PyObject *op)

Part of the Stable ABI.

Return the imaginary part of op as a C double.

If op is not a Python complex number object but has a __complex__() method, this method will first be called to convert op to a Python complex number object. If __complex__() is not defined then it falls back to call PyFloat_AsDouble() and returns 0.0 on success.

Upon failure, this method returns -1.0 with an exception set, so one should call PyErr_Occurred() to check for errors.

버전 3.13에서 변경: Use __complex__() if available.

Py_complex PyComplex_AsCComplex(PyObject *op)

복소수 op의 Py_complex 값을 반환합니다.

If op is not a Python complex number object but has a __complex__() method, this method will first be called to convert op to a Python complex number object. If __complex__() is not defined then it falls back to __float__(). If __float__() is not defined then it falls back to __index__().

Upon failure, this method returns Py_complex with real set to -1.0 and with an exception set, so one should call PyErr_Occurred() to check for errors.

버전 3.8에서 변경: Use __index__() if available.

바이트열 객체

These functions raise TypeError when expecting a bytes parameter and called with a non-bytes parameter.

type PyBytesObject

이 PyObject의 서브 형은 파이썬 바이트열 객체를 나타냅니다.

PyTypeObject PyBytes_Type

Part of the Stable ABI.

이 PyTypeObject의 인스턴스는 파이썬 바이트열 형을 나타냅니다; 파이썬 계층의 bytes와 같은 객체입니다.

int PyBytes_Check(PyObject *o)

객체 o가 바이트열 객체이거나 바이트열 형의 서브 형의 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyBytes_CheckExact(PyObject *o)

객체 o가 바이트열 객체이지만, 바이트열 형의 서브 형의 인스턴스는 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyBytes_FromString(const char *v)

Return value: New reference. Part of the Stable ABI.

성공하면 값으로 v 문자열의 복사본을 갖는 새 바이트열 객체를 반환하고, 실패하면 NULL을 반환합니다. 매개 변수 v는 NULL이 아니어야 합니다; 검사하지 않습니다.

PyObject *PyBytes_FromStringAndSize(const char *v, Py_ssize_t len)

Return value: New reference. Part of the Stable ABI.

성공하면 값이 v 문자열의 복사본이고 길이가 len인 새 바이트열 객체를 반환하고, 실패하면 NULL을 반환합니다. v가 NULL이면, 바이트열 객체의 내용은 초기화되지 않습니다.

PyObject *PyBytes_FromFormat(const char *format, ...)

Return value: New reference. Part of the Stable ABI.

C printf()-스타일 format 문자열과 가변 개수의 인자를 받아서, 결과 파이썬 바이트열 객체의 크기를 계산하고 그 안에 값이 포맷된 바이트열 객체를 반환합니다. 가변 인자는 C 형이어야 하며 format 문자열에 있는 포맷 문자들과 정확히 대응해야 합니다. 허용되는 포맷 문자는 다음과 같습니다:

포맷 문자

형

주석

%%

n/a

리터럴 % 문자.

%c

int

단일 바이트, C int로 표현됩니다.

%d

int

printf("%d")와 동등합니다. [1]

%u

unsigned int

printf("%u")와 동등합니다. [1]

%ld

long

printf("%ld")와 동등합니다. [1]

%lu

unsigned long

printf("%lu")와 동등합니다. [1]

%zd

Py_ssize_t

printf("%zd")와 동등합니다. [1]

%zu

size_t

printf("%zu")와 동등합니다. [1]

%i

int

printf("%i")와 동등합니다. [1]

%x

int

printf("%x")와 동등합니다. [1]

%s

const char*

널-종료 C 문자 배열.

%p

const void*

C 포인터의 16진수 표현. 플랫폼의 printf가 어떤 결과를 내는지에 상관없이 리터럴 0x로 시작함이 보장된다는 점을 제외하고는 거의 printf("%p")와 동등합니다.

인식할 수 없는 포맷 문자는 포맷 문자열의 나머지 부분이 모두 결과 객체에 그대로 복사되게 만들고, 추가 인자는 무시됩니다.

[1] (1,2,3,4,5,6,7,8)

정수 지정자 (d, u, ld, lu, zd, zu, i, x)에서: 0-변환 플래그는 정밀도를 지정해도 영향을 미칩니다.

PyObject *PyBytes_FromFormatV(const char *format, va_list vargs)

Return value: New reference. Part of the Stable ABI.

정확히 두 개의 인자를 취한다는 것을 제외하고는 PyBytes_FromFormat()과 같습니다.

PyObject *PyBytes_FromObject(PyObject *o)

Return value: New reference. Part of the Stable ABI.

버퍼 프로토콜을 구현하는 객체 o의 바이트열 표현을 반환합니다.

Py_ssize_t PyBytes_Size(PyObject *o)

Part of the Stable ABI.

바이트열 객체 o의 길이를 반환합니다.

Py_ssize_t PyBytes_GET_SIZE(PyObject *o)

Similar to PyBytes_Size(), but without error checking.

char *PyBytes_AsString(PyObject *o)

Part of the Stable ABI.

o의 내용에 대한 포인터를 반환합니다. 포인터는 len(o) + 1 바이트로 구성된 o의 내부 버퍼를 가리킵니다. 버퍼의 마지막 바이트는 다른 널(null) 바이트가 있는지에 관계없이 항상 널입니다. 객체가 PyBytes_FromStringAndSize(NULL, size)를 사용하여 방금 만들어진 경우가 아니면 데이터를 수정해서는 안 됩니다. 할당을 해제해서는 안 됩니다. o가 바이트열 객체가 아니면, PyBytes_AsString()은 NULL을 반환하고 TypeError를 발생시킵니다.

char *PyBytes_AS_STRING(PyObject *string)

Similar to PyBytes_AsString(), but without error checking.

int PyBytes_AsStringAndSize(PyObject *obj, char **buffer, Py_ssize_t *length)

Part of the Stable ABI.

Return the null-terminated contents of the object obj through the output variables buffer and length. Returns 0 on success.

length가 NULL이면, 바이트열 객체는 내장된 널 바이트를 포함할 수 없습니다; 만약 그렇다면 함수는 -1을 반환하고 ValueError를 발생시킵니다.

buffer는 obj의 내부 버퍼를 가리키게 되는데, 끝에 추가 널 바이트가 포함됩니다 (length에는 포함되지 않습니다). 객체가 PyBytes_FromStringAndSize(NULL, size)를 사용하여 방금 만들어진 경우가 아니면 데이터를 수정해서는 안 됩니다. 할당을 해제해서는 안 됩니다. obj가 바이트열 객체가 아니면 PyBytes_AsStringAndSize()는 -1을 반환하고 TypeError를 발생시킵니다.

버전 3.5에서 변경: 이전에는, 바이트열 객체에 널 바이트가 포함되어 있으면 TypeError가 발생했습니다.

void PyBytes_Concat(PyObject **bytes, PyObject *newpart)

Part of the Stable ABI.

bytes에 newpart의 내용을 덧붙인 새 바이트열 객체를 *bytes에 만듭니다; 호출자가 새 참조를 소유합니다. bytes의 예전 값에 대한 참조를 훔칩니다. 새 객체가 만들어질 수 없으면, bytes에 대한 예전 참조는 여전히 버려지고 *bytes의 값은 NULL로 설정됩니다; 적절한 예외가 설정됩니다.

void PyBytes_ConcatAndDel(PyObject **bytes, PyObject *newpart)

Part of the Stable ABI.

Create a new bytes object in *bytes containing the contents of newpart appended to bytes. This version releases the strong reference to newpart (i.e. decrements its reference count).

PyObject *PyBytes_Join(PyObject *sep, PyObject *iterable)

Similar to sep.join(iterable) in Python.

sep must be Python bytes object. (Note that PyUnicode_Join() accepts NULL separator and treats it as a space, whereas PyBytes_Join() doesn’t accept NULL separator.)

iterable must be an iterable object yielding objects that implement the buffer protocol.

On success, return a new bytes object. On error, set an exception and return NULL.

Added in version 3.14.

int _PyBytes_Resize(PyObject **bytes, Py_ssize_t newsize)

Resize a bytes object. newsize will be the new length of the bytes object. You can think of it as creating a new bytes object and destroying the old one, only more efficiently. Pass the address of an existing bytes object as an lvalue (it may be written into), and the new size desired. On success, *bytes holds the resized bytes object and 0 is returned; the address in *bytes may differ from its input value. If the reallocation fails, the original bytes object at *bytes is deallocated, *bytes is set to NULL, MemoryError is set, and -1 is returned.

바이트 배열 객체

type PyByteArrayObject

이 PyObject의 서브 형은 파이썬 bytearray 객체를 나타냅니다.

PyTypeObject PyByteArray_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 bytearray 형을 나타냅니다; 파이썬 계층의 bytearray와 같은 객체입니다.

형 검사 매크로

int PyByteArray_Check(PyObject *o)

객체 o가 bytearray 객체이거나 bytearray 형의 서브 형 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyByteArray_CheckExact(PyObject *o)

객체 o가 bytearray 객체이지만, bytearray 형의 서브 형 인스턴스는 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

직접 API 함수

PyObject *PyByteArray_FromObject(PyObject *o)

Return value: New reference. Part of the Stable ABI.

버퍼 프로토콜을 구현하는 임의의 객체(o)로부터 써서 새로운 bytearray 객체를 돌려줍니다.

On failure, return NULL with an exception set.

PyObject *PyByteArray_FromStringAndSize(const char *string, Py_ssize_t len)

Return value: New reference. Part of the Stable ABI.

Create a new bytearray object from string and its length, len.

On failure, return NULL with an exception set.

PyObject *PyByteArray_Concat(PyObject *a, PyObject *b)

Return value: New reference. Part of the Stable ABI.

바이트 배열 a 와 b를 이어붙여 새로운 bytearray로 반환합니다.

On failure, return NULL with an exception set.

Py_ssize_t PyByteArray_Size(PyObject *bytearray)

Part of the Stable ABI.

NULL 포인터를 확인한 후 bytearray의 크기를 반환합니다.

char *PyByteArray_AsString(PyObject *bytearray)

Part of the Stable ABI.

NULL 포인터를 확인한 후 bytearray의 내용을 char 배열로 반환합니다. 반환되는 배열에는 항상 여분의 널 바이트가 추가됩니다.

int PyByteArray_Resize(PyObject *bytearray, Py_ssize_t len)

Part of the Stable ABI.

bytearray의 내부 버퍼의 크기를 len으로 조정합니다.

매크로

이 매크로는 속도를 위해 안전을 희생하며 포인터를 확인하지 않습니다.

char *PyByteArray_AS_STRING(PyObject *bytearray)

Similar to PyByteArray_AsString(), but without error checking.

Py_ssize_t PyByteArray_GET_SIZE(PyObject *bytearray)

Similar to PyByteArray_Size(), but without error checking.

유니코드 객체와 코덱

유니코드 객체

파이썬 3.3에서 PEP 393 [https://peps.python.org/pep-0393/]을 구현한 이후, 유니코드 객체는 내부적으로 다양한 표현을 사용하여 전체 유니코드 문자 범위를 처리하면서 메모리 효율성을 유지합니다. 모든 코드 포인트가 128, 256 또는 65536 미만인 문자열에 대한 특별한 경우가 있습니다; 그렇지 않으면, 코드 포인트는 1114112 (전체 유니코드 범위) 미만이어야 합니다.

UTF-8 representation is created on demand and cached in the Unicode object.

참고

The Py_UNICODE representation has been removed since Python 3.12 with deprecated APIs. See PEP 623 [https://peps.python.org/pep-0623/] for more information.

유니코드 형

다음은 파이썬에서 유니코드 구현에 사용되는 기본 유니코드 객체 형입니다:

type Py_UCS4

type Py_UCS2

type Py_UCS1

Part of the Stable ABI.

이 형들은 각각 32비트, 16비트 및 8비트의 문자를 포함하기에 충분한 부호 없는 정수 형을 위한 typedef 입니다. 단일 유니코드 문자를 처리할 때는, Py_UCS4를 사용하십시오.

Added in version 3.3.

type Py_UNICODE

이것은 플랫폼에 따라 16비트 형이나 32비트 형인 wchar_t의 typedef 입니다.

버전 3.3에서 변경: 이전 버전에서, 이것은 빌드 시 파이썬의 “내로우(narrow)”나 “와이드(wide)” 유니코드 버전 중 어느 것을 선택했는지에 따라 16비트 형이나 32비트 형이었습니다.

Deprecated since version 3.13, will be removed in version 3.15.

type PyASCIIObject

type PyCompactUnicodeObject

type PyUnicodeObject

이 PyObject 서브 형들은 파이썬 유니코드 객체를 나타냅니다. 거의 모든 경우에, 유니코드 객체를 처리하는 모든 API 함수가 PyObject 포인터를 취하고 반환하므로 직접 사용해서는 안 됩니다.

Added in version 3.3.

PyTypeObject PyUnicode_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 유니코드 형을 나타냅니다. 파이썬 코드에 str로 노출됩니다.

The following APIs are C macros and static inlined functions for fast checks and access to internal read-only data of Unicode objects:

int PyUnicode_Check(PyObject *obj)

Return true if the object obj is a Unicode object or an instance of a Unicode subtype. This function always succeeds.

int PyUnicode_CheckExact(PyObject *obj)

Return true if the object obj is a Unicode object, but not an instance of a subtype. This function always succeeds.

int PyUnicode_READY(PyObject *unicode)

Returns 0. This API is kept only for backward compatibility.

Added in version 3.3.

버전 3.10부터 폐지됨: This API does nothing since Python 3.12.

Py_ssize_t PyUnicode_GET_LENGTH(PyObject *unicode)

Return the length of the Unicode string, in code points. unicode has to be a Unicode object in the “canonical” representation (not checked).

Added in version 3.3.

Py_UCS1 *PyUnicode_1BYTE_DATA(PyObject *unicode)

Py_UCS2 *PyUnicode_2BYTE_DATA(PyObject *unicode)

Py_UCS4 *PyUnicode_4BYTE_DATA(PyObject *unicode)

Return a pointer to the canonical representation cast to UCS1, UCS2 or UCS4 integer types for direct character access. No checks are performed if the canonical representation has the correct character size; use PyUnicode_KIND() to select the right function.

Added in version 3.3.

PyUnicode_1BYTE_KIND

PyUnicode_2BYTE_KIND

PyUnicode_4BYTE_KIND

PyUnicode_KIND() 매크로의 값을 반환합니다.

Added in version 3.3.

버전 3.12에서 변경: PyUnicode_WCHAR_KIND has been removed.

int PyUnicode_KIND(PyObject *unicode)

Return one of the PyUnicode kind constants (see above) that indicate how many bytes per character this Unicode object uses to store its data. unicode has to be a Unicode object in the “canonical” representation (not checked).

Added in version 3.3.

void *PyUnicode_DATA(PyObject *unicode)

Return a void pointer to the raw Unicode buffer. unicode has to be a Unicode object in the “canonical” representation (not checked).

Added in version 3.3.

void PyUnicode_WRITE(int kind, void *data, Py_ssize_t index, Py_UCS4 value)

Write into a canonical representation data (as obtained with PyUnicode_DATA()). This function performs no sanity checks, and is intended for usage in loops. The caller should cache the kind value and data pointer as obtained from other calls. index is the index in the string (starts at 0) and value is the new code point value which should be written to that location.

Added in version 3.3.

Py_UCS4 PyUnicode_READ(int kind, void *data, Py_ssize_t index)

규범적(canonical) 표현 data(PyUnicode_DATA()로 얻은 대로)에서 코드 포인트를 읽습니다. 검사나 준비(ready) 호출이 수행되지 않습니다.

Added in version 3.3.

Py_UCS4 PyUnicode_READ_CHAR(PyObject *unicode, Py_ssize_t index)

Read a character from a Unicode object unicode, which must be in the “canonical” representation. This is less efficient than PyUnicode_READ() if you do multiple consecutive reads.

Added in version 3.3.

Py_UCS4 PyUnicode_MAX_CHAR_VALUE(PyObject *unicode)

Return the maximum code point that is suitable for creating another string based on unicode, which must be in the “canonical” representation. This is always an approximation but more efficient than iterating over the string.

Added in version 3.3.

int PyUnicode_IsIdentifier(PyObject *unicode)

Part of the Stable ABI.

언어 정의에 따라 문자열이 유효한 식별자이면 1을 반환합니다, 섹션 식별자와 키워드. 그렇지 않으면 0을 반환합니다.

버전 3.9에서 변경: 문자열이 준비(ready)되지 않았을 때, 이 함수는 더는 Py_FatalError()를 호출하지 않습니다.

유니코드 문자 속성

유니코드는 다양한 문자 속성을 제공합니다. 가장 자주 필요한 것은 파이썬 구성에 따라 C 함수에 매핑되는 이러한 매크로를 통해 사용할 수 있습니다.

int Py_UNICODE_ISSPACE(Py_UCS4 ch)

ch가 공백 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISLOWER(Py_UCS4 ch)

ch가 소문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISUPPER(Py_UCS4 ch)

ch가 대문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISTITLE(Py_UCS4 ch)

ch가 제목 케이스 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISLINEBREAK(Py_UCS4 ch)

ch가 줄 바꿈 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISDECIMAL(Py_UCS4 ch)

ch가 10진수 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISDIGIT(Py_UCS4 ch)

ch가 디짓(digit) 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISNUMERIC(Py_UCS4 ch)

ch가 숫자(numeric) 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISALPHA(Py_UCS4 ch)

ch가 알파벳 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISALNUM(Py_UCS4 ch)

ch가 영숫자 문자인지에 따라 1이나 0을 반환합니다.

int Py_UNICODE_ISPRINTABLE(Py_UCS4 ch)

ch가 인쇄 가능한 문자인지에 따라 1이나 0을 반환합니다. 인쇄할 수 없는 문자는, 인쇄 가능한 것으로 간주하는 ASCII 스페이스(0x20)를 제외하고, 유니코드 문자 데이터베이스에서 “Other”나 “Separator”로 정의된 문자입니다. (이 문맥에서 인쇄 가능한 문자는 repr()이 문자열에 대해 호출될 때 이스케이프 되지 않아야 하는 문자임에 유의하십시오. sys.stdout이나 sys.stderr에 기록된 문자열의 처리와 관련이 없습니다.)

다음 API는 빠른 직접 문자 변환에 사용할 수 있습니다:

Py_UCS4 Py_UNICODE_TOLOWER(Py_UCS4 ch)

소문자로 변환된 문자 ch를 반환합니다.

Py_UCS4 Py_UNICODE_TOUPPER(Py_UCS4 ch)

대문자로 변환된 문자 ch를 반환합니다.

Py_UCS4 Py_UNICODE_TOTITLE(Py_UCS4 ch)

제목 케이스로 변환된 문자 ch를 반환합니다.

int Py_UNICODE_TODECIMAL(Py_UCS4 ch)

Return the character ch converted to a decimal positive integer. Return -1 if this is not possible. This function does not raise exceptions.

int Py_UNICODE_TODIGIT(Py_UCS4 ch)

Return the character ch converted to a single digit integer. Return -1 if this is not possible. This function does not raise exceptions.

double Py_UNICODE_TONUMERIC(Py_UCS4 ch)

Return the character ch converted to a double. Return -1.0 if this is not possible. This function does not raise exceptions.

다음 API를 사용하여 서로게이트를 다룰 수 있습니다:

int Py_UNICODE_IS_SURROGATE(Py_UCS4 ch)

ch가 서로게이트인지 확인합니다 (0xD800 <= ch <= 0xDFFF).

int Py_UNICODE_IS_HIGH_SURROGATE(Py_UCS4 ch)

ch가 상위 서로게이트인지 확인합니다 (0xD800 <= ch <= 0xDBFF).

int Py_UNICODE_IS_LOW_SURROGATE(Py_UCS4 ch)

ch가 하위 서로게이트인지 확인합니다 (0xDC00 <= ch <= 0xDFFF).

Py_UCS4 Py_UNICODE_JOIN_SURROGATES(Py_UCS4 high, Py_UCS4 low)

Join two surrogate code points and return a single Py_UCS4 value. high and low are respectively the leading and trailing surrogates in a surrogate pair. high must be in the range [0xD800; 0xDBFF] and low must be in the range [0xDC00; 0xDFFF].

유니코드 문자열 생성과 액세스

유니코드 객체를 만들고 기본 시퀀스 속성에 액세스하려면 다음 API를 사용하십시오:

PyObject *PyUnicode_New(Py_ssize_t size, Py_UCS4 maxchar)

Return value: New reference.

새 유니코드 객체를 만듭니다. maxchar은 문자열에 배치할 실제 최대 코드 포인트여야 합니다. 근삿값으로, 127, 255, 65535, 1114111 시퀀스에서 가장 가까운 값으로 올림 할 수 있습니다.

이것은 새 유니코드 객체를 할당하는 데 권장되는 방법입니다. 이 함수를 사용하여 만든 객체는 크기를 조정할 수 없습니다.

On error, set an exception and return NULL.

Added in version 3.3.

PyObject *PyUnicode_FromKindAndData(int kind, const void *buffer, Py_ssize_t size)

Return value: New reference.

주어진 kind(가능한 값은 PyUnicode_KIND()에 의해 반환된 PyUnicode_1BYTE_KIND 등입니다)로 새로운 유니코드 객체를 만듭니다. buffer는 kind에 따라 문자 당 1, 2 또는 4바이트의 size 단위의 배열을 가리켜야 합니다.

If necessary, the input buffer is copied and transformed into the canonical representation. For example, if the buffer is a UCS4 string (PyUnicode_4BYTE_KIND) and it consists only of codepoints in the UCS1 range, it will be transformed into UCS1 (PyUnicode_1BYTE_KIND).

Added in version 3.3.

PyObject *PyUnicode_FromStringAndSize(const char *str, Py_ssize_t size)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object from the char buffer str. The bytes will be interpreted as being UTF-8 encoded. The buffer is copied into the new object. The return value might be a shared object, i.e. modification of the data is not allowed.

This function raises SystemError when:

size < 0,

str is NULL and size > 0

버전 3.12에서 변경: str == NULL with size > 0 is not allowed anymore.

PyObject *PyUnicode_FromString(const char *str)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object from a UTF-8 encoded null-terminated char buffer str.

PyObject *PyUnicode_FromFormat(const char *format, ...)

Return value: New reference. Part of the Stable ABI.

Take a C printf()-style format string and a variable number of arguments, calculate the size of the resulting Python Unicode string and return a string with the values formatted into it. The variable arguments must be C types and must correspond exactly to the format characters in the format ASCII-encoded string.

A conversion specifier contains two or more characters and has the following components, which must occur in this order:

The '%' character, which marks the start of the specifier.

Conversion flags (optional), which affect the result of some conversion types.

Minimum field width (optional). If specified as an '*' (asterisk), the actual width is given in the next argument, which must be of type int, and the object to convert comes after the minimum field width and optional precision.

Precision (optional), given as a '.' (dot) followed by the precision. If specified as '*' (an asterisk), the actual precision is given in the next argument, which must be of type int, and the value to convert comes after the precision.

Length modifier (optional).

Conversion type.

The conversion flag characters are:

Flag

Meaning

0

The conversion will be zero padded for numeric values.

-

The converted value is left adjusted (overrides the 0 flag if both are given).

The length modifiers for following integer conversions (d, i, o, u, x, or X) specify the type of the argument (int by default):

Modifier

Types

l

long or unsigned long

ll

long long or unsigned long long

j

intmax_t or uintmax_t

z

size_t or ssize_t

t

ptrdiff_t

The length modifier l for following conversions s or V specify that the type of the argument is const wchar_t*.

The conversion specifiers are:

Conversion Specifier

형

주석

%

n/a

The literal % character.

d, i

Specified by the length modifier

The decimal representation of a signed C integer.

u

Specified by the length modifier

The decimal representation of an unsigned C integer.

o

Specified by the length modifier

The octal representation of an unsigned C integer.

x

Specified by the length modifier

The hexadecimal representation of an unsigned C integer (lowercase).

X

Specified by the length modifier

The hexadecimal representation of an unsigned C integer (uppercase).

c

int

A single character.

s

const char* or const wchar_t*

널-종료 C 문자 배열.

p

const void*

The hex representation of a C pointer. Mostly equivalent to printf("%p") except that it is guaranteed to start with the literal 0x regardless of what the platform’s printf yields.

A

PyObject*

ascii()를 호출한 결과.

U

PyObject*

유니코드 객체.

V

PyObject*, const char* or const wchar_t*

유니코드 객체(NULL일 수 있습니다)와 두 번째 매개 변수로서 널-종료 C 문자 배열 (첫 번째 매개 변수가 NULL이면 사용됩니다).

S

PyObject*

PyObject_Str()을 호출한 결과.

R

PyObject*

PyObject_Repr()을 호출한 결과.

T

PyObject*

Get the fully qualified name of an object type; call PyType_GetFullyQualifiedName().

#T

PyObject*

Similar to T format, but use a colon (:) as separator between the module name and the qualified name.

N

PyTypeObject*

Get the fully qualified name of a type; call PyType_GetFullyQualifiedName().

#N

PyTypeObject*

Similar to N format, but use a colon (:) as separator between the module name and the qualified name.

참고

The width formatter unit is number of characters rather than bytes. The precision formatter unit is number of bytes or wchar_t items (if the length modifier l is used) for "%s" and "%V" (if the PyObject* argument is NULL), and a number of characters for "%A", "%U", "%S", "%R" and "%V" (if the PyObject* argument is not NULL).

참고

Unlike to C printf() the 0 flag has effect even when a precision is given for integer conversions (d, i, u, o, x, or X).

버전 3.2에서 변경: "%lld"와 "%llu"에 대한 지원이 추가되었습니다.

버전 3.3에서 변경: "%li", "%lli" 및 "%zi"에 대한 지원이 추가되었습니다.

버전 3.4에서 변경: "%s", "%A", "%U", "%V", "%S", "%R"에 대한 너비와 정밀도 포매터 지원이 추가되었습니다.

버전 3.12에서 변경: Support for conversion specifiers o and X. Support for length modifiers j and t. Length modifiers are now applied to all integer conversions. Length modifier l is now applied to conversion specifiers s and V. Support for variable width and precision *. Support for flag -.

An unrecognized format character now sets a SystemError. In previous versions it caused all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded.

버전 3.13에서 변경: Support for %T, %#T, %N and %#N formats added.

PyObject *PyUnicode_FromFormatV(const char *format, va_list vargs)

Return value: New reference. Part of the Stable ABI.

정확히 두 개의 인자를 취한다는 점을 제외하면 PyUnicode_FromFormat()과 동일합니다.

PyObject *PyUnicode_FromObject(PyObject *obj)

Return value: New reference. Part of the Stable ABI.

Copy an instance of a Unicode subtype to a new true Unicode object if necessary. If obj is already a true Unicode object (not a subtype), return a new strong reference to the object.

유니코드나 이의 서브 형 이외의 객체는 TypeError를 발생시킵니다.

PyObject *PyUnicode_FromEncodedObject(PyObject *obj, const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

인코딩된 객체 obj를 유니코드 객체로 디코딩합니다.

bytes, bytearray 및 기타 바이트열류 객체는 주어진 encoding에 따라 errors로 정의한 에러 처리를 사용하여 디코딩됩니다. 둘 다 NULL이 될 수 있고, 이 경우 인터페이스는 기본값을 사용합니다 (자세한 내용은 내장 코덱를 참조하십시오).

유니코드 객체를 포함한 다른 모든 객체는 TypeError가 설정되도록 합니다.

API는 에러가 있으면 NULL을 반환합니다. 호출자는 반환된 객체의 참조 횟수를 감소시킬 책임이 있습니다.

Py_ssize_t PyUnicode_GetLength(PyObject *unicode)

Part of the Stable ABI since version 3.7.

유니코드 객체의 길이를 코드 포인트로 반환합니다.

On error, set an exception and return -1.

Added in version 3.3.

Py_ssize_t PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start, PyObject *from, Py_ssize_t from_start, Py_ssize_t how_many)

Copy characters from one Unicode object into another. This function performs character conversion when necessary and falls back to memcpy() if possible. Returns -1 and sets an exception on error, otherwise returns the number of copied characters.

Added in version 3.3.

Py_ssize_t PyUnicode_Fill(PyObject *unicode, Py_ssize_t start, Py_ssize_t length, Py_UCS4 fill_char)

문자로 문자열을 채웁니다: fill_char을 unicode[start:start+length]에 씁니다.

fill_char이 문자열 최대 문자보다 크거나, 문자열에 둘 이상의 참조가 있으면 실패합니다.

기록된 문자 수를 반환하거나, 에러 시 -1을 반환하고 예외를 발생시킵니다.

Added in version 3.3.

int PyUnicode_WriteChar(PyObject *unicode, Py_ssize_t index, Py_UCS4 character)

Part of the Stable ABI since version 3.7.

문자열에 문자를 씁니다. 문자열은 PyUnicode_New()를 통해 만들었어야 합니다. 유니코드 문자열은 불변이므로, 문자열을 공유하거나 아직 해시 하지 않아야 합니다.

이 함수는 unicode가 유니코드 객체인지, 인덱스가 범위를 벗어났는지, 객체가 안전하게 수정될 수 있는지 (즉, 참조 횟수가 1인지) 확인합니다.

Return 0 on success, -1 on error with an exception set.

Added in version 3.3.

Py_UCS4 PyUnicode_ReadChar(PyObject *unicode, Py_ssize_t index)

Part of the Stable ABI since version 3.7.

Read a character from a string. This function checks that unicode is a Unicode object and the index is not out of bounds, in contrast to PyUnicode_READ_CHAR(), which performs no error checking.

Return character on success, -1 on error with an exception set.

Added in version 3.3.

PyObject *PyUnicode_Substring(PyObject *unicode, Py_ssize_t start, Py_ssize_t end)

Return value: New reference. Part of the Stable ABI since version 3.7.

Return a substring of unicode, from character index start (included) to character index end (excluded). Negative indices are not supported. On error, set an exception and return NULL.

Added in version 3.3.

Py_UCS4 *PyUnicode_AsUCS4(PyObject *unicode, Py_UCS4 *buffer, Py_ssize_t buflen, int copy_null)

Part of the Stable ABI since version 3.7.

Copy the string unicode into a UCS4 buffer, including a null character, if copy_null is set. Returns NULL and sets an exception on error (in particular, a SystemError if buflen is smaller than the length of unicode). buffer is returned on success.

Added in version 3.3.

Py_UCS4 *PyUnicode_AsUCS4Copy(PyObject *unicode)

Part of the Stable ABI since version 3.7.

Copy the string unicode into a new UCS4 buffer that is allocated using PyMem_Malloc(). If this fails, NULL is returned with a MemoryError set. The returned buffer always has an extra null code point appended.

Added in version 3.3.

로케일 인코딩

현재 로케일 인코딩을 사용하여 운영 체제에서 온 텍스트를 디코딩 할 수 있습니다.

PyObject *PyUnicode_DecodeLocaleAndSize(const char *str, Py_ssize_t length, const char *errors)

Return value: New reference. Part of the Stable ABI since version 3.7.

안드로이드와 VxWorks의 UTF-8이나 다른 플랫폼의 현재 로케일 인코딩의 문자열을 디코딩합니다. 지원되는 에러 처리기는 "strict"와 "surrogateescape"(PEP 383 [https://peps.python.org/pep-0383/])입니다. 디코더는 errors가 NULL이면 "strict" 에러 처리기를 사용합니다. str은 널 문자로 끝나야 하지만 널 문자를 포함할 수 없습니다.

Use PyUnicode_DecodeFSDefaultAndSize() to decode a string from the filesystem encoding and error handler.

This function ignores the Python UTF-8 Mode.

더 보기

Py_DecodeLocale() 함수.

Added in version 3.3.

버전 3.7에서 변경: 이 함수는 이제 안드로이드를 제외하고 surrogateescape 에러 처리기에 현재 로케일 인코딩도 사용합니다. 이전에는, Py_DecodeLocale()이 surrogateescape에 사용되었고, 현재 로케일 인코딩은 strict에 사용되었습니다.

PyObject *PyUnicode_DecodeLocale(const char *str, const char *errors)

Return value: New reference. Part of the Stable ABI since version 3.7.

Similar to PyUnicode_DecodeLocaleAndSize(), but compute the string length using strlen().

Added in version 3.3.

PyObject *PyUnicode_EncodeLocale(PyObject *unicode, const char *errors)

Return value: New reference. Part of the Stable ABI since version 3.7.

유니코드 객체를 안드로이드와 VxWorks에서 UTF-8로 인코딩하거나, 다른 플랫폼에서 현재 로케일 인코딩으로 인코딩합니다. 지원되는 에러 처리기는 "strict"와 "surrogateescape"(PEP 383 [https://peps.python.org/pep-0383/])입니다. 인코더는 errors가 NULL이면 "strict" 에러 처리기를 사용합니다. bytes 객체를 반환합니다. unicode는 내장된 널 문자를 포함할 수 없습니다.

Use PyUnicode_EncodeFSDefault() to encode a string to the filesystem encoding and error handler.

This function ignores the Python UTF-8 Mode.

더 보기

Py_EncodeLocale() 함수.

Added in version 3.3.

버전 3.7에서 변경: 이 함수는 이제 안드로이드를 제외하고 surrogateescape 에러 처리기에 현재 로케일 인코딩도 사용합니다. 이전에는 Py_EncodeLocale()이 surrogateescape에 사용되었고, 현재 로케일 인코딩은 strict에 사용되었습니다.

파일 시스템 인코딩

Functions encoding to and decoding from the filesystem encoding and error handler (PEP 383 [https://peps.python.org/pep-0383/] and PEP 529 [https://peps.python.org/pep-0529/]).

To encode file names to bytes during argument parsing, the "O&" converter should be used, passing PyUnicode_FSConverter() as the conversion function:

int PyUnicode_FSConverter(PyObject *obj, void *result)

Part of the Stable ABI.

ParseTuple converter: encode str objects – obtained directly or through the os.PathLike interface – to bytes using PyUnicode_EncodeFSDefault(); bytes objects are output as-is. result must be a PyBytesObject* which must be released when it is no longer used.

Added in version 3.1.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

인자 구문 분석 중에 파일 이름을 str로 디코딩하려면, "O&" 변환기를 사용하고 PyUnicode_FSDecoder()를 변환 함수로 전달해야 합니다:

int PyUnicode_FSDecoder(PyObject *obj, void *result)

Part of the Stable ABI.

ParseTuple converter: decode bytes objects – obtained either directly or indirectly through the os.PathLike interface – to str using PyUnicode_DecodeFSDefaultAndSize(); str objects are output as-is. result must be a PyUnicodeObject* which must be released when it is no longer used.

Added in version 3.2.

버전 3.6에서 변경: 경로류 객체를 받아들입니다.

PyObject *PyUnicode_DecodeFSDefaultAndSize(const char *str, Py_ssize_t size)

Return value: New reference. Part of the Stable ABI.

Decode a string from the filesystem encoding and error handler.

If you need to decode a string from the current locale encoding, use PyUnicode_DecodeLocaleAndSize().

더 보기

Py_DecodeLocale() 함수.

버전 3.6에서 변경: The filesystem error handler is now used.

PyObject *PyUnicode_DecodeFSDefault(const char *str)

Return value: New reference. Part of the Stable ABI.

Decode a null-terminated string from the filesystem encoding and error handler.

If the string length is known, use PyUnicode_DecodeFSDefaultAndSize().

버전 3.6에서 변경: The filesystem error handler is now used.

PyObject *PyUnicode_EncodeFSDefault(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

Encode a Unicode object to the filesystem encoding and error handler, and return bytes. Note that the resulting bytes object can contain null bytes.

If you need to encode a string to the current locale encoding, use PyUnicode_EncodeLocale().

더 보기

Py_EncodeLocale() 함수.

Added in version 3.2.

버전 3.6에서 변경: The filesystem error handler is now used.

wchar_t 지원

지원하는 플랫폼에 대한 wchar_t 지원:

PyObject *PyUnicode_FromWideChar(const wchar_t *wstr, Py_ssize_t size)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object from the wchar_t buffer wstr of the given size. Passing -1 as the size indicates that the function must itself compute the length, using wcslen(). Return NULL on failure.

Py_ssize_t PyUnicode_AsWideChar(PyObject *unicode, wchar_t *wstr, Py_ssize_t size)

Part of the Stable ABI.

Copy the Unicode object contents into the wchar_t buffer wstr. At most size wchar_t characters are copied (excluding a possibly trailing null termination character). Return the number of wchar_t characters copied or -1 in case of an error.

When wstr is NULL, instead return the size that would be required to store all of unicode including a terminating null.

Note that the resulting wchar_t* string may or may not be null-terminated. It is the responsibility of the caller to make sure that the wchar_t* string is null-terminated in case this is required by the application. Also, note that the wchar_t* string might contain null characters, which would cause the string to be truncated when used with most C functions.

wchar_t *PyUnicode_AsWideCharString(PyObject *unicode, Py_ssize_t *size)

Part of the Stable ABI since version 3.7.

Convert the Unicode object to a wide character string. The output string always ends with a null character. If size is not NULL, write the number of wide characters (excluding the trailing null termination character) into *size. Note that the resulting wchar_t string might contain null characters, which would cause the string to be truncated when used with most C functions. If size is NULL and the wchar_t* string contains null characters a ValueError is raised.

Returns a buffer allocated by PyMem_New (use PyMem_Free() to free it) on success. On error, returns NULL and *size is undefined. Raises a MemoryError if memory allocation is failed.

Added in version 3.2.

버전 3.7에서 변경: Raises a ValueError if size is NULL and the wchar_t* string contains null characters.

내장 코덱

파이썬은 속도를 위해 C로 작성된 내장 코덱 집합을 제공합니다. 이러한 코덱들은 모두 다음 함수들을 통해 직접 사용할 수 있습니다.

다음 API의 대부분은 두 개의 인자 encoding과 errors를 취하며, 내장 str() 문자열 객체 생성자의 것들과 같은 의미입니다.

Setting encoding to NULL causes the default encoding to be used which is UTF-8. The file system calls should use PyUnicode_FSConverter() for encoding file names. This uses the filesystem encoding and error handler internally.

에러 처리는 errors로 설정되는데, 코덱에 대해 정의된 기본 처리를 사용함을 의미하는 NULL로 설정될 수도 있습니다. 모든 내장 코덱에 대한 기본 에러 처리는 “strict” 입니다 (ValueError가 발생합니다).

The codecs all use a similar interface. Only deviations from the following generic ones are documented for simplicity.

일반 코덱

다음은 일반 코덱 API입니다:

PyObject *PyUnicode_Decode(const char *str, Py_ssize_t size, const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the encoded string str. encoding and errors have the same meaning as the parameters of the same name in the str() built-in function. The codec to be used is looked up using the Python codec registry. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_AsEncodedString(PyObject *unicode, const char *encoding, const char *errors)

Return value: New reference. Part of the Stable ABI.

유니코드 객체를 인코딩하고 결과를 파이썬 bytes 객체로 반환합니다. encoding과 errors는 유니코드 encode() 메서드의 같은 이름의 매개 변수와 같은 의미입니다. 사용할 코덱은 파이썬 코덱 레지스트리를 사용하여 조회됩니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

UTF-8 코덱

다음은 UTF-8 코덱 API입니다:

PyObject *PyUnicode_DecodeUTF8(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the UTF-8 encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_DecodeUTF8Stateful(const char *str, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)

Return value: New reference. Part of the Stable ABI.

consumed가 NULL이면, PyUnicode_DecodeUTF8()처럼 동작합니다. consumed가 NULL이 아니면, 후행 불완전한 UTF-8 바이트 시퀀스는 에러로 처리되지 않습니다. 이러한 바이트는 디코딩되지 않으며 디코딩된 바이트 수는 consumed에 저장됩니다.

PyObject *PyUnicode_AsUTF8String(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

UTF-8을 사용하여 유니코드 객체를 인코딩하고 결과를 파이썬 bytes 객체로 반환합니다. 에러 처리는 “strict” 입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

The function fails if the string contains surrogate code points (U+D800 - U+DFFF).

const char *PyUnicode_AsUTF8AndSize(PyObject *unicode, Py_ssize_t *size)

Part of the Stable ABI since version 3.10.

유니코드 객체의 UTF-8 인코딩에 대한 포인터를 반환하고, 인코딩된 표현의 크기를 (바이트 단위로) size에 저장합니다. size 인자는 NULL일 수 있습니다; 이 경우 크기가 저장되지 않습니다. 반환된 버퍼에는 다른 널 코드 포인트가 있는지에 관계없이, 항상 추가 널 바이트가 추가됩니다 (size에 포함되지 않습니다).

On error, set an exception, set size to -1 (if it’s not NULL) and return NULL.

The function fails if the string contains surrogate code points (U+D800 - U+DFFF).

This caches the UTF-8 representation of the string in the Unicode object, and subsequent calls will return a pointer to the same buffer. The caller is not responsible for deallocating the buffer. The buffer is deallocated and pointers to it become invalid when the Unicode object is garbage collected.

Added in version 3.3.

버전 3.7에서 변경: 반환형은 이제 char *가 아니라 const char *입니다.

버전 3.10에서 변경: This function is a part of the limited API.

const char *PyUnicode_AsUTF8(PyObject *unicode)

PyUnicode_AsUTF8AndSize()와 같지만, 크기를 저장하지 않습니다.

Added in version 3.3.

버전 3.7에서 변경: 반환형은 이제 char *가 아니라 const char *입니다.

UTF-32 코덱

다음은 UTF-32 코덱 API입니다:

PyObject *PyUnicode_DecodeUTF32(const char *str, Py_ssize_t size, const char *errors, int *byteorder)

Return value: New reference. Part of the Stable ABI.

UTF-32로 인코딩된 버퍼 문자열에서 size 바이트를 디코딩하고 해당 유니코드 객체를 반환합니다. errors(NULL이 아니면)는 에러 처리를 정의합니다. 기본값은 “strict”입니다.

byteorder가 NULL이 아니면, 디코더는 지정된 바이트 순서를 사용하여 디코딩을 시작합니다:

*byteorder == -1: little endian
*byteorder == 0:  native order
*byteorder == 1:  big endian

*byteorder가 0이고, 입력 데이터의 처음 4바이트가 바이트 순서 표시(BOM)이면, 디코더가 이 바이트 순서로 전환되고 BOM은 결과 유니코드 문자열에 복사되지 않습니다. *byteorder가 -1이나 1이면, 모든 바이트 순서 표시가 출력에 복사됩니다.

완료 후, *byteorder는 입력 데이터의 끝에서 현재 바이트 순서로 설정됩니다.

byteorder가 NULL이면, 코덱은 네이티브 순서 모드로 시작합니다.

코덱에서 예외가 발생하면 NULL을 반환합니다.

PyObject *PyUnicode_DecodeUTF32Stateful(const char *str, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)

Return value: New reference. Part of the Stable ABI.

consumed가 NULL이면, PyUnicode_DecodeUTF32()처럼 동작합니다. consumed가 NULL이 아니면, PyUnicode_DecodeUTF32Stateful() 은 후행 불완전 UTF-32 바이트 시퀀스(가령 4로 나누어떨어지지 않는 바이트 수)를 에러로 처리하지 않습니다. 이러한 바이트는 디코딩되지 않으며 디코딩된 바이트 수는 consumed에 저장됩니다.

PyObject *PyUnicode_AsUTF32String(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

네이티브 바이트 순서로 UTF-32 인코딩을 사용하여 파이썬 바이트 문자열을 반환합니다. 문자열은 항상 BOM 마크로 시작합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

UTF-16 코덱

다음은 UTF-16 코덱 API입니다:

PyObject *PyUnicode_DecodeUTF16(const char *str, Py_ssize_t size, const char *errors, int *byteorder)

Return value: New reference. Part of the Stable ABI.

UTF-16으로 인코딩된 버퍼 문자열에서 size 바이트를 디코딩하고 해당 유니코드 객체를 반환합니다. errors(NULL이 아니면)는 에러 처리를 정의합니다. 기본값은 “strict”입니다.

byteorder가 NULL이 아니면, 디코더는 지정된 바이트 순서를 사용하여 디코딩을 시작합니다:

*byteorder == -1: little endian
*byteorder == 0:  native order
*byteorder == 1:  big endian

*byteorder가 0이고, 입력 데이터의 처음 2바이트가 바이트 순서 표시(BOM)이면, 디코더는 이 바이트 순서로 전환되고 BOM은 결과 유니코드 문자열에 복사되지 않습니다. *byteorder가 -1이나 1이면 모든 바이트 순서 표시가 출력에 복사됩니다 (\ufeff나 \ufffe 문자가 됩니다).

After completion, *byteorder is set to the current byte order at the end of input data.

byteorder가 NULL이면, 코덱은 네이티브 순서 모드로 시작합니다.

코덱에서 예외가 발생하면 NULL을 반환합니다.

PyObject *PyUnicode_DecodeUTF16Stateful(const char *str, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)

Return value: New reference. Part of the Stable ABI.

consumed가 NULL이면, PyUnicode_DecodeUTF16()처럼 동작합니다. consumed가 NULL이 아니면, PyUnicode_DecodeUTF16Stateful() 은 후행 불완전 UTF-16 바이트 시퀀스(가령 홀수 바이트 수나 분할 서로게이트 쌍)를 에러로 처리하지 않습니다. 이러한 바이트는 디코딩되지 않으며 디코딩된 바이트 수는 consumed에 저장됩니다.

PyObject *PyUnicode_AsUTF16String(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

네이티브 바이트 순서로 UTF-16 인코딩을 사용하여 파이썬 바이트 문자열을 반환합니다. 문자열은 항상 BOM 마크로 시작합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

UTF-7 코덱

다음은 UTF-7 코덱 API입니다:

PyObject *PyUnicode_DecodeUTF7(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the UTF-7 encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_DecodeUTF7Stateful(const char *str, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)

Return value: New reference. Part of the Stable ABI.

consumed가 NULL이면, PyUnicode_DecodeUTF7()처럼 동작합니다. consumed가 NULL이 아니면, 후행 불완전한 UTF-7 base-64 섹션은 에러로 처리되지 않습니다. 이러한 바이트는 디코딩되지 않으며 디코딩된 바이트 수는 consumed에 저장됩니다.

유니코드 이스케이프 코덱

다음은 “유니코드 이스케이프(Unicode Escape)” 코덱 API입니다:

PyObject *PyUnicode_DecodeUnicodeEscape(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the Unicode-Escape encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_AsUnicodeEscapeString(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

유니코드 이스케이프를 사용하여 유니코드 객체를 인코딩하고 결과를 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

원시 유니코드 이스케이프 코덱

다음은 “원시 유니코드 이스케이프(Raw Unicode Escape)” 코덱 API입니다:

PyObject *PyUnicode_DecodeRawUnicodeEscape(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the Raw-Unicode-Escape encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

원시 유니코드 이스케이프를 사용하여 유니코드 객체를 인코딩하고 결과를 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

Latin-1 코덱

다음은 Latin-1 코덱 API입니다: Latin-1은 처음 256개의 유니코드 서수에 해당하며 인코딩 중에 코덱에서 이들만 허용됩니다.

PyObject *PyUnicode_DecodeLatin1(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the Latin-1 encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_AsLatin1String(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

Latin-1을 사용하여 유니코드 객체를 인코딩하고 결과를 파이썬 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

ASCII 코덱

다음은 ASCII 코덱 API입니다. 7비트 ASCII 데이터만 허용됩니다. 다른 모든 코드는 에러를 생성합니다.

PyObject *PyUnicode_DecodeASCII(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the ASCII encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_AsASCIIString(PyObject *unicode)

Return value: New reference. Part of the Stable ABI.

ASCII를 사용하여 유니코드 객체를 인코딩하고 결과를 파이썬 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

문자 맵 코덱

This codec is special in that it can be used to implement many different codecs (and this is in fact what was done to obtain most of the standard codecs included in the encodings package). The codec uses mappings to encode and decode characters. The mapping objects provided must support the __getitem__() mapping interface; dictionaries and sequences work well.

다음은 매핑 코덱 API입니다:

PyObject *PyUnicode_DecodeCharmap(const char *str, Py_ssize_t length, PyObject *mapping, const char *errors)

Return value: New reference. Part of the Stable ABI.

Create a Unicode object by decoding size bytes of the encoded string str using the given mapping object. Return NULL if an exception was raised by the codec.

mapping이 NULL이면, Latin-1 디코딩이 적용됩니다. 그렇지 않으면 mapping은 바이트 서수(0에서 255 사이의 정수)를 유니코드 문자열, 정수(유니코드 서수로 해석됩니다) 또는 None으로 매핑해야합니다. 매핑되지 않은 데이터 바이트(None, 0xFFFE 또는 '\ufffe'로 매핑되는 것뿐만 아니라, LookupError를 유발하는 것)은 정의되지 않은 매핑으로 처리되어 에러를 발생시킵니다.

PyObject *PyUnicode_AsCharmapString(PyObject *unicode, PyObject *mapping)

Return value: New reference. Part of the Stable ABI.

주어진 mapping 객체를 사용하여 유니코드 객체를 인코딩하고 결과를 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

mapping 객체는 유니코드 서수 정수를 bytes 객체, 0에서 255 사이의 정수 또는 None으로 매핑해야 합니다. None에 매핑되는 것뿐만 아니라 매핑되지 않은 문자 서수(LookupError를 유발하는 것)는 “정의되지 않은 매핑”으로 처리되어 에러가 발생합니다.

다음 코덱 API는 유니코드를 유니코드로 매핑한다는 점에서 특별합니다.

PyObject *PyUnicode_Translate(PyObject *unicode, PyObject *table, const char *errors)

Return value: New reference. Part of the Stable ABI.

문자 매핑 테이블을 적용하여 문자열을 변환하고 결과 유니코드 객체를 반환합니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

매핑 테이블은 유니코드 서수 정수를 유니코드 서수 정수나 None(문자가 삭제되도록 합니다)에 매핑해야 합니다.

Mapping tables need only provide the __getitem__() interface; dictionaries and sequences work well. Unmapped character ordinals (ones which cause a LookupError) are left untouched and are copied as-is.

errors는 코덱에서의 일반적인 의미입니다. 기본 에러 처리를 사용함을 나타내는 NULL일 수 있습니다.

윈도우 용 MBCS 코덱

다음은 MBCS 코덱 API입니다. 현재 윈도우에서만 사용할 수 있으며 Win32 MBCS 변환기를 사용하여 변환을 구현합니다. MBCS(또는 DBCS)는 단지 하나가 아니라 인코딩 클래스임에 유의하십시오. 대상 인코딩은 코덱을 실행하는 기계의 사용자 설정에 의해 정의됩니다.

PyObject *PyUnicode_DecodeMBCS(const char *str, Py_ssize_t size, const char *errors)

Return value: New reference. Part of the Stable ABI on Windows since version 3.7.

Create a Unicode object by decoding size bytes of the MBCS encoded string str. Return NULL if an exception was raised by the codec.

PyObject *PyUnicode_DecodeMBCSStateful(const char *str, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)

Return value: New reference. Part of the Stable ABI on Windows since version 3.7.

consumed가 NULL이면, PyUnicode_DecodeMBCS()처럼 동작합니다. consumed가 NULL이 아니면, PyUnicode_DecodeMBCSStateful() 은 후행 선행(lead) 바이트를 디코딩하지 않고 디코딩된 바이트 수가 consumed에 저장됩니다.

PyObject *PyUnicode_AsMBCSString(PyObject *unicode)

Return value: New reference. Part of the Stable ABI on Windows since version 3.7.

MBCS를 사용하여 유니코드 객체를 인코딩하고 결과를 파이썬 bytes 객체로 반환합니다. 에러 처리는 “strict”입니다. 코덱에서 예외가 발생하면 NULL을 반환합니다.

PyObject *PyUnicode_EncodeCodePage(int code_page, PyObject *unicode, const char *errors)

Return value: New reference. Part of the Stable ABI on Windows since version 3.7.

Encode the Unicode object using the specified code page and return a Python bytes object. Return NULL if an exception was raised by the codec. Use CP_ACP code page to get the MBCS encoder.

Added in version 3.3.

메서드와 슬롯

메서드와 슬롯 함수

다음 API는 입력의 유니코드 객체와 문자열을 (설명에서 문자열이라고 하겠습니다) 처리할 수 있으며 적절하게 유니코드 객체나 정수를 반환합니다.

예외가 발생하면 모두 NULL이나 -1을 반환합니다.

PyObject *PyUnicode_Concat(PyObject *left, PyObject *right)

Return value: New reference. Part of the Stable ABI.

두 문자열을 이어붙여 하나의 새로운 유니코드 문자열을 제공합니다.

PyObject *PyUnicode_Split(PyObject *unicode, PyObject *sep, Py_ssize_t maxsplit)

Return value: New reference. Part of the Stable ABI.

문자열을 분할하여 유니코드 문자열 리스트를 제공합니다. sep이 NULL이면, 모든 공백 부분 문자열에서 분할이 수행됩니다. 그렇지 않으면, 주어진 구분자에서 분할이 일어납니다. 최대 maxsplit 분할이 수행됩니다. 음수이면, 제한이 설정되지 않습니다. 구분자는 결과 리스트에 포함되지 않습니다.

PyObject *PyUnicode_Splitlines(PyObject *unicode, int keepends)

Return value: New reference. Part of the Stable ABI.

Split a Unicode string at line breaks, returning a list of Unicode strings. CRLF is considered to be one line break. If keepends is 0, the Line break characters are not included in the resulting strings.

PyObject *PyUnicode_Join(PyObject *separator, PyObject *seq)

Return value: New reference. Part of the Stable ABI.

주어진 separator를 사용하여 문자열 시퀀스를 연결하고 결과 유니코드 문자열을 반환합니다.

Py_ssize_t PyUnicode_Tailmatch(PyObject *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI.

Return 1 if substr matches unicode[start:end] at the given tail end (direction == -1 means to do a prefix match, direction == 1 a suffix match), 0 otherwise. Return -1 if an error occurred.

Py_ssize_t PyUnicode_Find(PyObject *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI.

Return the first position of substr in unicode[start:end] using the given direction (direction == 1 means to do a forward search, direction == -1 a backward search). The return value is the index of the first match; a value of -1 indicates that no match was found, and -2 indicates that an error occurred and an exception has been set.

Py_ssize_t PyUnicode_FindChar(PyObject *unicode, Py_UCS4 ch, Py_ssize_t start, Py_ssize_t end, int direction)

Part of the Stable ABI since version 3.7.

Return the first position of the character ch in unicode[start:end] using the given direction (direction == 1 means to do a forward search, direction == -1 a backward search). The return value is the index of the first match; a value of -1 indicates that no match was found, and -2 indicates that an error occurred and an exception has been set.

Added in version 3.3.

버전 3.7에서 변경: start and end are now adjusted to behave like unicode[start:end].

Py_ssize_t PyUnicode_Count(PyObject *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end)

Part of the Stable ABI.

Return the number of non-overlapping occurrences of substr in unicode[start:end]. Return -1 if an error occurred.

PyObject *PyUnicode_Replace(PyObject *unicode, PyObject *substr, PyObject *replstr, Py_ssize_t maxcount)

Return value: New reference. Part of the Stable ABI.

Replace at most maxcount occurrences of substr in unicode with replstr and return the resulting Unicode object. maxcount == -1 means replace all occurrences.

int PyUnicode_Compare(PyObject *left, PyObject *right)

Part of the Stable ABI.

두 문자열을 비교하고 각각 작음, 같음, 큼에 대해 -1, 0, 1을 반환합니다.

이 함수는 실패 시 -1을 반환하므로, 에러를 확인하기 위해 PyErr_Occurred()를 호출해야 합니다.

더 보기

The PyUnicode_Equal() function.

int PyUnicode_Equal(PyObject *a, PyObject *b)

Part of the Stable ABI since version 3.14.

Test if two strings are equal:

Return 1 if a is equal to b.

Return 0 if a is not equal to b.

Set a TypeError exception and return -1 if a or b is not a str object.

The function always succeeds if a and b are str objects.

The function works for str subclasses, but does not honor custom __eq__() method.

더 보기

The PyUnicode_Compare() function.

Added in version 3.14.

int PyUnicode_EqualToUTF8AndSize(PyObject *unicode, const char *string, Py_ssize_t size)

Part of the Stable ABI since version 3.13.

Compare a Unicode object with a char buffer which is interpreted as being UTF-8 or ASCII encoded and return true (1) if they are equal, or false (0) otherwise. If the Unicode object contains surrogate code points (U+D800 - U+DFFF) or the C string is not valid UTF-8, false (0) is returned.

이 함수는 예외를 발생시키지 않습니다.

Added in version 3.13.

int PyUnicode_EqualToUTF8(PyObject *unicode, const char *string)

Part of the Stable ABI since version 3.13.

Similar to PyUnicode_EqualToUTF8AndSize(), but compute string length using strlen(). If the Unicode object contains null characters, false (0) is returned.

Added in version 3.13.

int PyUnicode_CompareWithASCIIString(PyObject *unicode, const char *string)

Part of the Stable ABI.

Compare a Unicode object, unicode, with string and return -1, 0, 1 for less than, equal, and greater than, respectively. It is best to pass only ASCII-encoded strings, but the function interprets the input string as ISO-8859-1 if it contains non-ASCII characters.

이 함수는 예외를 발생시키지 않습니다.

PyObject *PyUnicode_RichCompare(PyObject *left, PyObject *right, int op)

Return value: New reference. Part of the Stable ABI.

두 유니코드 문자열을 풍부한 비교(rich comparison) 하고 다음 중 하나를 반환합니다:

예외가 발생하면 NULL

Py_True or Py_False for successful comparisons

Py_NotImplemented in case the type combination is unknown

Possible values for op are Py_GT, Py_GE, Py_EQ, Py_NE, Py_LT, and Py_LE.

PyObject *PyUnicode_Format(PyObject *format, PyObject *args)

Return value: New reference. Part of the Stable ABI.

format과 args에서 새 문자열 객체를 반환합니다; 이것은 format % args와 유사합니다.

int PyUnicode_Contains(PyObject *unicode, PyObject *substr)

Part of the Stable ABI.

Check whether substr is contained in unicode and return true or false accordingly.

substr has to coerce to a one element Unicode string. -1 is returned if there was an error.

void PyUnicode_InternInPlace(PyObject **p_unicode)

Part of the Stable ABI.

Intern the argument *p_unicode in place. The argument must be the address of a pointer variable pointing to a Python Unicode string object. If there is an existing interned string that is the same as *p_unicode, it sets *p_unicode to it (releasing the reference to the old string object and creating a new strong reference to the interned string object), otherwise it leaves *p_unicode alone and interns it.

(Clarification: even though there is a lot of talk about references, think of this function as reference-neutral. You must own the object you pass in; after the call you no longer own the passed-in reference, but you newly own the result.)

This function never raises an exception. On error, it leaves its argument unchanged without interning it.

Instances of subclasses of str may not be interned, that is, PyUnicode_CheckExact(*p_unicode) must be true. If it is not, then – as with any other error – the argument is left unchanged.

Note that interned strings are not “immortal”. You must keep a reference to the result to benefit from interning.

PyObject *PyUnicode_InternFromString(const char *str)

Return value: New reference. Part of the Stable ABI.

A combination of PyUnicode_FromString() and PyUnicode_InternInPlace(), meant for statically allocated strings.

Return a new (“owned”) reference to either a new Unicode string object that has been interned, or an earlier interned string object with the same value.

Python may keep a reference to the result, or make it immortal, preventing it from being garbage-collected promptly. For interning an unbounded number of different strings, such as ones coming from user input, prefer calling PyUnicode_FromString() and PyUnicode_InternInPlace() directly.

CPython 구현 상세: Strings interned this way are made immortal.

PyUnicodeWriter

The PyUnicodeWriter API can be used to create a Python str object.

Added in version 3.14.

type PyUnicodeWriter

A Unicode writer instance.

The instance must be destroyed by PyUnicodeWriter_Finish() on success, or PyUnicodeWriter_Discard() on error.

PyUnicodeWriter *PyUnicodeWriter_Create(Py_ssize_t length)

Create a Unicode writer instance.

Set an exception and return NULL on error.

PyObject *PyUnicodeWriter_Finish(PyUnicodeWriter *writer)

Return the final Python str object and destroy the writer instance.

Set an exception and return NULL on error.

void PyUnicodeWriter_Discard(PyUnicodeWriter *writer)

Discard the internal Unicode buffer and destroy the writer instance.

If writer is NULL, no operation is performed.

int PyUnicodeWriter_WriteChar(PyUnicodeWriter *writer, Py_UCS4 ch)

Write the single Unicode character ch into writer.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_WriteUTF8(PyUnicodeWriter *writer, const char *str, Py_ssize_t size)

Decode the string str from UTF-8 in strict mode and write the output into writer.

size is the string length in bytes. If size is equal to -1, call strlen(str) to get the string length.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

See also PyUnicodeWriter_DecodeUTF8Stateful().

int PyUnicodeWriter_WriteWideChar(PyUnicodeWriter *writer, const wchar_t *str, Py_ssize_t size)

Writer the wide string str into writer.

size is a number of wide characters. If size is equal to -1, call wcslen(str) to get the string length.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_WriteUCS4(PyUnicodeWriter *writer, Py_UCS4 *str, Py_ssize_t size)

Writer the UCS4 string str into writer.

size is a number of UCS4 characters.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_WriteStr(PyUnicodeWriter *writer, PyObject *obj)

Call PyObject_Str() on obj and write the output into writer.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_WriteRepr(PyUnicodeWriter *writer, PyObject *obj)

Call PyObject_Repr() on obj and write the output into writer.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_WriteSubstring(PyUnicodeWriter *writer, PyObject *str, Py_ssize_t start, Py_ssize_t end)

Write the substring str[start:end] into writer.

str must be Python str object. start must be greater than or equal to 0, and less than or equal to end. end must be less than or equal to str length.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_Format(PyUnicodeWriter *writer, const char *format, ...)

Similar to PyUnicode_FromFormat(), but write the output directly into writer.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

int PyUnicodeWriter_DecodeUTF8Stateful(PyUnicodeWriter *writer, const char *string, Py_ssize_t length, const char *errors, Py_ssize_t *consumed)

Decode the string str from UTF-8 with errors error handler and write the output into writer.

size is the string length in bytes. If size is equal to -1, call strlen(str) to get the string length.

errors is an error handler name, such as "replace". If errors is NULL, use the strict error handler.

If consumed is not NULL, set *consumed to the number of decoded bytes on success. If consumed is NULL, treat trailing incomplete UTF-8 byte sequences as an error.

On success, return 0. On error, set an exception, leave the writer unchanged, and return -1.

See also PyUnicodeWriter_WriteUTF8().

튜플 객체

type PyTupleObject

이 PyObject의 서브 형은 파이썬 튜플 객체를 나타냅니다.

PyTypeObject PyTuple_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 튜플 형을 나타냅니다. 파이썬 계층의 tuple과 같은 객체입니다.

int PyTuple_Check(PyObject *p)

p가 튜플 객체이거나 튜플 형의 서브 형의 인스턴스면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

int PyTuple_CheckExact(PyObject *p)

p가 튜플 객체이지만, 튜플 형의 서브 형의 인스턴스는 아니면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

PyObject *PyTuple_New(Py_ssize_t len)

Return value: New reference. Part of the Stable ABI.

Return a new tuple object of size len, or NULL with an exception set on failure.

PyObject *PyTuple_Pack(Py_ssize_t n, ...)

Return value: New reference. Part of the Stable ABI.

Return a new tuple object of size n, or NULL with an exception set on failure. The tuple values are initialized to the subsequent n C arguments pointing to Python objects. PyTuple_Pack(2, a, b) is equivalent to Py_BuildValue("(OO)", a, b).

Py_ssize_t PyTuple_Size(PyObject *p)

Part of the Stable ABI.

Take a pointer to a tuple object, and return the size of that tuple. On error, return -1 and with an exception set.

Py_ssize_t PyTuple_GET_SIZE(PyObject *p)

Like PyTuple_Size(), but without error checking.

PyObject *PyTuple_GetItem(PyObject *p, Py_ssize_t pos)

Return value: Borrowed reference. Part of the Stable ABI.

Return the object at position pos in the tuple pointed to by p. If pos is negative or out of bounds, return NULL and set an IndexError exception.

The returned reference is borrowed from the tuple p (that is: it is only valid as long as you hold a reference to p). To get a strong reference, use Py_NewRef(PyTuple_GetItem(...)) or PySequence_GetItem().

PyObject *PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos)

Return value: Borrowed reference.

PyTuple_GetItem()와 비슷하지만, 인자를 확인하지 않습니다.

PyObject *PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high)

Return value: New reference. Part of the Stable ABI.

Return the slice of the tuple pointed to by p between low and high, or NULL with an exception set on failure.

This is the equivalent of the Python expression p[low:high]. Indexing from the end of the tuple is not supported.

int PyTuple_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)

Part of the Stable ABI.

p가 가리키는 튜플의 pos 위치에 객체 o에 대한 참조를 삽입합니다. 성공하면 0을 반환합니다. pos가 범위를 벗어나면, -1을 반환하고 IndexError 예외를 설정합니다.

참고

이 함수는 o에 대한 참조를 “훔치고” 영향을 받는 위치에서 튜플에 이미 있는 항목에 대한 참조를 버립니다(discard).

void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o)

PyTuple_SetItem()과 비슷하지만, 에러 검사는 하지 않으며 새로운 튜플을 채울 때*만* 사용해야 합니다.

Bounds checking is performed as an assertion if Python is built in debug mode or with assertions.

참고

This function “steals” a reference to o, and, unlike PyTuple_SetItem(), does not discard a reference to any item that is being replaced; any reference in the tuple at position pos will be leaked.

경고

This macro should only be used on tuples that are newly created. Using this macro on a tuple that is already in use (or in other words, has a refcount > 1) could lead to undefined behavior.

int _PyTuple_Resize(PyObject **p, Py_ssize_t newsize)

튜플 크기를 조정하는 데 사용할 수 있습니다. newsize는 튜플의 새로운 길이가 됩니다. 튜플은 불변이라고 여겨지므로, 객체에 대해 참조가 하나만 있을 때만 사용해야 합니다. 튜플이 코드의 다른 부분에 이미 알려졌으면 이것을 사용하지 마십시오. 튜플은 항상 끝에서 커지거나 줄어듭니다. 이것을 오래된 튜플을 파괴하고 새 튜플을 만드는 것으로 생각하십시오, 단지 더 효율적일 뿐입니다. 성공하면 0을 반환합니다. 클라이언트 코드는, *p의 결괏값이 이 함수를 호출하기 전과 같다고 가정해서는 안 됩니다. *p가 참조하는 객체가 바뀌면 원래 *p는 파괴됩니다. 실패하면, -1을 반환하고, *p를 NULL로 설정하고, MemoryError 나 SystemError를 발생시킵니다.

구조체 시퀀스 객체

구조체 시퀀스(struct sequence) 객체는 namedtuple() 객체의 C 등가물입니다, 즉 어트리뷰트를 통해 항목에 액세스할 수 있는 시퀀스입니다. 구조체 시퀀스를 만들려면, 먼저 특정 구조체 시퀀스 형을 만들어야 합니다.

PyTypeObject *PyStructSequence_NewType(PyStructSequence_Desc *desc)

Return value: New reference. Part of the Stable ABI.

아래에 설명된 desc의 데이터로 새로운 구조체 시퀀스 형을 만듭니다. 결과 형의 인스턴스는 PyStructSequence_New()로 만들 수 있습니다.

Return NULL with an exception set on failure.

void PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)

desc로 구조체 시퀀스 형 type을 재자리에서 초기화합니다.

int PyStructSequence_InitType2(PyTypeObject *type, PyStructSequence_Desc *desc)

Like PyStructSequence_InitType(), but returns 0 on success and -1 with an exception set on failure.

Added in version 3.4.

type PyStructSequence_Desc

Part of the Stable ABI (including all members).

만들 구조체 시퀀스 형의 메타 정보를 포함합니다.

const char *name

Fully qualified name of the type; null-terminated UTF-8 encoded. The name must contain the module name.

const char *doc

Pointer to docstring for the type or NULL to omit.

PyStructSequence_Field *fields

Pointer to NULL-terminated array with field names of the new type.

int n_in_sequence

Number of fields visible to the Python side (if used as tuple).

type PyStructSequence_Field

Part of the Stable ABI (including all members).

Describes a field of a struct sequence. As a struct sequence is modeled as a tuple, all fields are typed as PyObject*. The index in the fields array of the PyStructSequence_Desc determines which field of the struct sequence is described.

const char *name

Name for the field or NULL to end the list of named fields, set to PyStructSequence_UnnamedField to leave unnamed.

const char *doc

Field docstring or NULL to omit.

const char *const PyStructSequence_UnnamedField

Part of the Stable ABI since version 3.11.

이름 없는 상태로 남겨두기 위한 필드 이름의 특수 값.

버전 3.9에서 변경: 형이 char *에서 변경되었습니다.

PyObject *PyStructSequence_New(PyTypeObject *type)

Return value: New reference. Part of the Stable ABI.

PyStructSequence_NewType()으로 만든 type의 인스턴스를 만듭니다.

Return NULL with an exception set on failure.

PyObject *PyStructSequence_GetItem(PyObject *p, Py_ssize_t pos)

Return value: Borrowed reference. Part of the Stable ABI.

Return the object at position pos in the struct sequence pointed to by p.

Bounds checking is performed as an assertion if Python is built in debug mode or with assertions.

PyObject *PyStructSequence_GET_ITEM(PyObject *p, Py_ssize_t pos)

Return value: Borrowed reference.

Alias to PyStructSequence_GetItem().

버전 3.13에서 변경: Now implemented as an alias to PyStructSequence_GetItem().

void PyStructSequence_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)

Part of the Stable ABI.

구조체 시퀀스 p의 인덱스 pos에 있는 필드를 값 o로 설정합니다. PyTuple_SET_ITEM()과 마찬가지로, 이것은 새로운 인스턴스를 채울 때만 사용해야 합니다.

Bounds checking is performed as an assertion if Python is built in debug mode or with assertions.

참고

이 함수는 o에 대한 참조를 “훔칩니다”.

void PyStructSequence_SET_ITEM(PyObject *p, Py_ssize_t *pos, PyObject *o)

Alias to PyStructSequence_SetItem().

버전 3.13에서 변경: Now implemented as an alias to PyStructSequence_SetItem().

리스트 객체

type PyListObject

이 PyObject의 서브 형은 파이썬 리스트 객체를 나타냅니다.

PyTypeObject PyList_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 리스트 형을 나타냅니다. 이것은 파이썬 계층의 list와 같은 객체입니다.

int PyList_Check(PyObject *p)

p가 리스트 객체나 리스트 형의 서브 형 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyList_CheckExact(PyObject *p)

p가 리스트 객체이지만 리스트 형의 서브 형의 인스턴스가 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyList_New(Py_ssize_t len)

Return value: New reference. Part of the Stable ABI.

성공하면 길이 len 인 새 리스트를, 실패하면 NULL을 반환합니다.

참고

If len is greater than zero, the returned list object’s items are set to NULL. Thus you cannot use abstract API functions such as PySequence_SetItem() or expose the object to Python code before setting all items to a real object with PyList_SetItem() or PyList_SET_ITEM(). The following APIs are safe APIs before the list is fully initialized: PyList_SetItem() and PyList_SET_ITEM().

Py_ssize_t PyList_Size(PyObject *list)

Part of the Stable ABI.

list에서 리스트 객체의 길이를 반환합니다; 이는 리스트 객체에 대한 len(list)와 동등합니다.

Py_ssize_t PyList_GET_SIZE(PyObject *list)

Similar to PyList_Size(), but without error checking.

PyObject *PyList_GetItemRef(PyObject *list, Py_ssize_t index)

Return value: New reference. Part of the Stable ABI since version 3.13.

Return the object at position index in the list pointed to by list. The position must be non-negative; indexing from the end of the list is not supported. If index is out of bounds (<0 or >=len(list)), return NULL and set an IndexError exception.

Added in version 3.13.

PyObject *PyList_GetItem(PyObject *list, Py_ssize_t index)

Return value: Borrowed reference. Part of the Stable ABI.

Like PyList_GetItemRef(), but returns a borrowed reference instead of a strong reference.

PyObject *PyList_GET_ITEM(PyObject *list, Py_ssize_t i)

Return value: Borrowed reference.

Similar to PyList_GetItem(), but without error checking.

int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item)

Part of the Stable ABI.

리스트의 인덱스 index에 있는 항목을 item으로 설정합니다. 성공하면 0을 반환합니다. index가 범위를 벗어나면, -1을 반환하고 IndexError 예외를 설정합니다.

참고

이 함수는 item에 대한 참조를 “훔치고” 영향을 받는 위치의 리스트에 이미 있는 항목에 대한 참조를 버립니다.

void PyList_SET_ITEM(PyObject *list, Py_ssize_t i, PyObject *o)

에러 검사 없는 PyList_SetItem()의 매크로 형식. 일반적으로 이전 내용이 없는 새 리스트를 채우는 데 사용됩니다.

Bounds checking is performed as an assertion if Python is built in debug mode or with assertions.

참고

이 매크로는 item에 대한 참조를 “훔치고”, PyList_SetItem()과는 달리 대체되는 항목에 대한 참조를 버리지 않습니다; list 의 i 위치에 있는 참조는 누수를 일으킵니다.

int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item)

Part of the Stable ABI.

항목 item을 리스트 list의 인덱스 index 앞에 삽입합니다. 성공하면 0을 반환합니다; 실패하면 -1을 반환하고 예외를 설정합니다. list.insert(index, item)에 해당합니다.

int PyList_Append(PyObject *list, PyObject *item)

Part of the Stable ABI.

리스트 list의 끝에 객체 item을 추가합니다. 성공하면 0을 반환합니다; 실패하면 -1을 반환하고 예외를 설정합니다. list.append(item)에 해당합니다.

PyObject *PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high)

Return value: New reference. Part of the Stable ABI.

list에서 low 와 high 사이에있는 객체들을 포함하는 리스트를 반환합니다. 실패하면 NULL을 반환하고 예외를 설정합니다. list[low:high]에 해당합니다. 리스트 끝에서부터의 인덱싱은 지원되지 않습니다.

int PyList_SetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high, PyObject *itemlist)

Part of the Stable ABI.

low와 high 사이의 list슬라이스를 itemlist의 내용으로 설정합니다. list[low:high] = itemlist에 해당합니다. itemlist는 NULL 일 수 있는데, 빈 리스트의 대입을 나타냅니다 (슬라이스 삭제). 성공하면 0을, 실패하면 -1을 반환합니다. 리스트 끝에서부터의 인덱싱은 지원되지 않습니다.

int PyList_Extend(PyObject *list, PyObject *iterable)

Extend list with the contents of iterable. This is the same as PyList_SetSlice(list, PY_SSIZE_T_MAX, PY_SSIZE_T_MAX, iterable) and analogous to list.extend(iterable) or list += iterable.

Raise an exception and return -1 if list is not a list object. Return 0 on success.

Added in version 3.13.

int PyList_Clear(PyObject *list)

Remove all items from list. This is the same as PyList_SetSlice(list, 0, PY_SSIZE_T_MAX, NULL) and analogous to list.clear() or del list[:].

Raise an exception and return -1 if list is not a list object. Return 0 on success.

Added in version 3.13.

int PyList_Sort(PyObject *list)

Part of the Stable ABI.

list 항목을 제자리에서 정렬합니다. 성공하면 0을, 실패하면 -1을 반환합니다. 이것은 list.sort()와 동등합니다.

int PyList_Reverse(PyObject *list)

Part of the Stable ABI.

list의 항목을 제자리에서 뒤집습니다. 성공하면 0을, 실패하면 -1을 반환합니다. 이것은 list.reverse()와 동등합니다.

PyObject *PyList_AsTuple(PyObject *list)

Return value: New reference. Part of the Stable ABI.

list의 내용을 포함하는 새 튜플 객체를 반환합니다; tuple(list)와 동등합니다.

딕셔너리 객체

type PyDictObject

이 PyObject의 서브 형은 파이썬 딕셔너리 객체를 나타냅니다.

PyTypeObject PyDict_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 딕셔너리 형을 나타냅니다. 이것은 파이썬 계층의 dict와 같은 객체입니다.

int PyDict_Check(PyObject *p)

p가 dict 객체이거나 dict 형의 서브 형의 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyDict_CheckExact(PyObject *p)

p가 dict 객체이지만, dict 형의 서브 형의 인스턴스는 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyDict_New()

Return value: New reference. Part of the Stable ABI.

새로운 빈 딕셔너리를 반환하거나, 실패하면 NULL을 반환합니다.

PyObject *PyDictProxy_New(PyObject *mapping)

Return value: New reference. Part of the Stable ABI.

읽기 전용 동작을 강제하는 매핑을 위한 types.MappingProxyType 객체를 반환합니다. 이것은 일반적으로 비 동적 클래스 형을 위한 딕셔너리의 수정을 방지하기 위해 뷰를 만드는 데 사용됩니다.

void PyDict_Clear(PyObject *p)

Part of the Stable ABI.

기존 딕셔너리의 모든 키-값 쌍을 비웁니다.

int PyDict_Contains(PyObject *p, PyObject *key)

Part of the Stable ABI.

딕셔너리 p에 key가 포함되어 있는지 확인합니다. p의 항목이 key와 일치하면 1을 반환하고, 그렇지 않으면 0을 반환합니다. 에러면 -1을 반환합니다. 이는 파이썬 표현식 key in p와 동등합니다.

int PyDict_ContainsString(PyObject *p, const char *key)

This is the same as PyDict_Contains(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

PyObject *PyDict_Copy(PyObject *p)

Return value: New reference. Part of the Stable ABI.

p와 같은 키-값 쌍을 포함하는 새 딕셔너리를 반환합니다.

int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val)

Part of the Stable ABI.

딕셔너리 p에 val을 key 키로 삽입합니다. key는 해시 가능해야 합니다. 그렇지 않으면 TypeError가 발생합니다. 성공하면 0을, 실패하면 -1을 반환합니다. 이 함수는 val에 대한 참조를 훔치지 않습니다.

int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val)

Part of the Stable ABI.

This is the same as PyDict_SetItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyDict_DelItem(PyObject *p, PyObject *key)

Part of the Stable ABI.

Remove the entry in dictionary p with key key. key must be hashable; if it isn’t, TypeError is raised. If key is not in the dictionary, KeyError is raised. Return 0 on success or -1 on failure.

int PyDict_DelItemString(PyObject *p, const char *key)

Part of the Stable ABI.

This is the same as PyDict_DelItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyDict_GetItemRef(PyObject *p, PyObject *key, PyObject **result)

Part of the Stable ABI since version 3.13.

Return a new strong reference to the object from dictionary p which has a key key:

If the key is present, set *result to a new strong reference to the value and return 1.

If the key is missing, set *result to NULL and return 0.

On error, raise an exception and return -1.

Added in version 3.13.

See also the PyObject_GetItem() function.

PyObject *PyDict_GetItem(PyObject *p, PyObject *key)

Return value: Borrowed reference. Part of the Stable ABI.

Return a borrowed reference to the object from dictionary p which has a key key. Return NULL if the key key is missing without setting an exception.

참고

Exceptions that occur while this calls __hash__() and __eq__() methods are silently ignored. Prefer the PyDict_GetItemWithError() function instead.

버전 3.10에서 변경: Calling this API without GIL held had been allowed for historical reason. It is no longer allowed.

PyObject *PyDict_GetItemWithError(PyObject *p, PyObject *key)

Return value: Borrowed reference. Part of the Stable ABI.

예외를 억제하지 않는 PyDict_GetItem()의 변형입니다. 예외가 발생하면 예외를 설정하고 NULL을 반환합니다. 키가 없으면 예외를 설정하지 않고 NULL을 반환합니다.

PyObject *PyDict_GetItemString(PyObject *p, const char *key)

Return value: Borrowed reference. Part of the Stable ABI.

This is the same as PyDict_GetItem(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

참고

Exceptions that occur while this calls __hash__() and __eq__() methods or while creating the temporary str object are silently ignored. Prefer using the PyDict_GetItemWithError() function with your own PyUnicode_FromString() key instead.

int PyDict_GetItemStringRef(PyObject *p, const char *key, PyObject **result)

Part of the Stable ABI since version 3.13.

Similar to PyDict_GetItemRef(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

PyObject *PyDict_SetDefault(PyObject *p, PyObject *key, PyObject *defaultobj)

Return value: Borrowed reference.

이것은 파이썬 수준의 dict.setdefault()와 같습니다. 존재하면, 딕셔너리 p에서 key에 해당하는 값을 반환합니다. 키가 dict에 없으면, 값 defaultobj로 삽입되고, defaultobj가 반환됩니다. 이 함수는 key의 해시 함수를 조회 및 삽입을 위해 독립적으로 평가하는 대신 한 번만 평가합니다.

Added in version 3.4.

int PyDict_SetDefaultRef(PyObject *p, PyObject *key, PyObject *default_value, PyObject **result)

Inserts default_value into the dictionary p with a key of key if the key is not already present in the dictionary. If result is not NULL, then *result is set to a strong reference to either default_value, if the key was not present, or the existing value, if key was already present in the dictionary. Returns 1 if the key was present and default_value was not inserted, or 0 if the key was not present and default_value was inserted. On failure, returns -1, sets an exception, and sets *result to NULL.

For clarity: if you have a strong reference to default_value before calling this function, then after it returns, you hold a strong reference to both default_value and *result (if it’s not NULL). These may refer to the same object: in that case you hold two separate references to it.

Added in version 3.13.

int PyDict_Pop(PyObject *p, PyObject *key, PyObject **result)

Remove key from dictionary p and optionally return the removed value. Do not raise KeyError if the key missing.

If the key is present, set *result to a new reference to the removed value if result is not NULL, and return 1.

If the key is missing, set *result to NULL if result is not NULL, and return 0.

On error, raise an exception and return -1.

Similar to dict.pop(), but without the default value and not raising KeyError if the key missing.

Added in version 3.13.

int PyDict_PopString(PyObject *p, const char *key, PyObject **result)

Similar to PyDict_Pop(), but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

Added in version 3.13.

PyObject *PyDict_Items(PyObject *p)

Return value: New reference. Part of the Stable ABI.

딕셔너리의 모든 항목을 포함하는 PyListObject를 반환합니다.

PyObject *PyDict_Keys(PyObject *p)

Return value: New reference. Part of the Stable ABI.

딕셔너리의 모든 키를 포함하는 PyListObject를 반환합니다.

PyObject *PyDict_Values(PyObject *p)

Return value: New reference. Part of the Stable ABI.

딕셔너리 p의 모든 값을 포함하는 PyListObject를 반환합니다.

Py_ssize_t PyDict_Size(PyObject *p)

Part of the Stable ABI.

딕셔너리에 있는 항목의 수를 반환합니다. 이는 딕셔너리에 대한 len(p)와 동등합니다.

int PyDict_Next(PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue)

Part of the Stable ABI.

Iterate over all key-value pairs in the dictionary p. The Py_ssize_t referred to by ppos must be initialized to 0 prior to the first call to this function to start the iteration; the function returns true for each pair in the dictionary, and false once all pairs have been reported. The parameters pkey and pvalue should either point to PyObject* variables that will be filled in with each key and value, respectively, or may be NULL. Any references returned through them are borrowed. ppos should not be altered during iteration. Its value represents offsets within the internal dictionary structure, and since the structure is sparse, the offsets are not consecutive.

예를 들면:

PyObject *key, *value;
Py_ssize_t pos = 0;

while (PyDict_Next(self->dict, &pos, &key, &value)) {
    /* do something interesting with the values... */
    ...
}

딕셔너리 p는 이터레이션 중에 변경해서는 안 됩니다. 딕셔너리를 이터레이트 할 때 값을 변경하는 것은 안전하지만, 키 집합이 변경되지 않는 한만 그렇습니다. 예를 들면:

PyObject *key, *value;
Py_ssize_t pos = 0;

while (PyDict_Next(self->dict, &pos, &key, &value)) {
    long i = PyLong_AsLong(value);
    if (i == -1 && PyErr_Occurred()) {
        return -1;
    }
    PyObject *o = PyLong_FromLong(i + 1);
    if (o == NULL)
        return -1;
    if (PyDict_SetItem(self->dict, key, o) < 0) {
        Py_DECREF(o);
        return -1;
    }
    Py_DECREF(o);
}

The function is not thread-safe in the free-threaded build without external synchronization. You can use Py_BEGIN_CRITICAL_SECTION to lock the dictionary while iterating over it:

Py_BEGIN_CRITICAL_SECTION(self->dict);
while (PyDict_Next(self->dict, &pos, &key, &value)) {
    ...
}
Py_END_CRITICAL_SECTION();

int PyDict_Merge(PyObject *a, PyObject *b, int override)

Part of the Stable ABI.

매핑 객체 b를 이터레이트 하면서, 키-값 쌍을 딕셔너리 a에 추가합니다. b는 딕셔너리거나 PyMapping_Keys()와 PyObject_GetItem()를 지원하는 모든 객체일 수 있습니다. override가 참이면, a에 있는 기존 쌍이 b에서 일치하는 키가 있으면 교체되고, 그렇지 않으면 a와 일치하는 키가 없을 때만 쌍이 추가됩니다. 성공하면 0을 반환하고, 예외가 발생하면 -1을 반환합니다.

int PyDict_Update(PyObject *a, PyObject *b)

Part of the Stable ABI.

이는 C에서 PyDict_Merge(a, b, 1)와 같고, 두 번째 인자에 “keys” 어트리뷰트가 없을 때 PyDict_Update()가 키-값 쌍의 시퀀스에 대해 이터레이트 하지 않는다는 점만 제외하면, 파이썬에서 a.update(b)와 유사합니다. 성공하면 0을 반환하고, 예외가 발생하면 -1을 반환합니다.

int PyDict_MergeFromSeq2(PyObject *a, PyObject *seq2, int override)

Part of the Stable ABI.

seq2의 키-값 쌍으로 딕셔너리 a를 갱신하거나 병합합니다. seq2는 키-값 쌍으로 간주하는 길이 2의 이터러블 객체를 생성하는 이터러블 객체여야 합니다. 중복 키가 있으면, override가 참이면 마지막이 승리하고, 그렇지 않으면 첫 번째가 승리합니다. 성공 시 0을 반환하고, 예외가 발생하면 -1을 반환합니다. 동등한 파이썬은 이렇습니다(반환 값 제외)

def PyDict_MergeFromSeq2(a, seq2, override):
    for key, value in seq2:
        if override or key not in a:
            a[key] = value

int PyDict_AddWatcher(PyDict_WatchCallback callback)

Register callback as a dictionary watcher. Return a non-negative integer id which must be passed to future calls to PyDict_Watch(). In case of error (e.g. no more watcher IDs available), return -1 and set an exception.

Added in version 3.12.

int PyDict_ClearWatcher(int watcher_id)

Clear watcher identified by watcher_id previously returned from PyDict_AddWatcher(). Return 0 on success, -1 on error (e.g. if the given watcher_id was never registered.)

Added in version 3.12.

int PyDict_Watch(int watcher_id, PyObject *dict)

Mark dictionary dict as watched. The callback granted watcher_id by PyDict_AddWatcher() will be called when dict is modified or deallocated. Return 0 on success or -1 on error.

Added in version 3.12.

int PyDict_Unwatch(int watcher_id, PyObject *dict)

Mark dictionary dict as no longer watched. The callback granted watcher_id by PyDict_AddWatcher() will no longer be called when dict is modified or deallocated. The dict must previously have been watched by this watcher. Return 0 on success or -1 on error.

Added in version 3.12.

type PyDict_WatchEvent

Enumeration of possible dictionary watcher events: PyDict_EVENT_ADDED, PyDict_EVENT_MODIFIED, PyDict_EVENT_DELETED, PyDict_EVENT_CLONED, PyDict_EVENT_CLEARED, or PyDict_EVENT_DEALLOCATED.

Added in version 3.12.

typedef int (*PyDict_WatchCallback)(PyDict_WatchEvent event, PyObject *dict, PyObject *key, PyObject *new_value)

Type of a dict watcher callback function.

If event is PyDict_EVENT_CLEARED or PyDict_EVENT_DEALLOCATED, both key and new_value will be NULL. If event is PyDict_EVENT_ADDED or PyDict_EVENT_MODIFIED, new_value will be the new value for key. If event is PyDict_EVENT_DELETED, key is being deleted from the dictionary and new_value will be NULL.

PyDict_EVENT_CLONED occurs when dict was previously empty and another dict is merged into it. To maintain efficiency of this operation, per-key PyDict_EVENT_ADDED events are not issued in this case; instead a single PyDict_EVENT_CLONED is issued, and key will be the source dictionary.

The callback may inspect but must not modify dict; doing so could have unpredictable effects, including infinite recursion. Do not trigger Python code execution in the callback, as it could modify the dict as a side effect.

If event is PyDict_EVENT_DEALLOCATED, taking a new reference in the callback to the about-to-be-destroyed dictionary will resurrect it and prevent it from being freed at this time. When the resurrected object is destroyed later, any watcher callbacks active at that time will be called again.

Callbacks occur before the notified modification to dict takes place, so the prior state of dict can be inspected.

If the callback sets an exception, it must return -1; this exception will be printed as an unraisable exception using PyErr_WriteUnraisable(). Otherwise it should return 0.

There may already be a pending exception set on entry to the callback. In this case, the callback should return 0 with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.

Added in version 3.12.

집합 객체

This section details the public API for set and frozenset objects. Any functionality not listed below is best accessed using either the abstract object protocol (including PyObject_CallMethod(), PyObject_RichCompareBool(), PyObject_Hash(), PyObject_Repr(), PyObject_IsTrue(), PyObject_Print(), and PyObject_GetIter()) or the abstract number protocol (including PyNumber_And(), PyNumber_Subtract(), PyNumber_Or(), PyNumber_Xor(), PyNumber_InPlaceAnd(), PyNumber_InPlaceSubtract(), PyNumber_InPlaceOr(), and PyNumber_InPlaceXor()).

type PySetObject

This subtype of PyObject is used to hold the internal data for both set and frozenset objects. It is like a PyDictObject in that it is a fixed size for small sets (much like tuple storage) and will point to a separate, variable sized block of memory for medium and large sized sets (much like list storage). None of the fields of this structure should be considered public and all are subject to change. All access should be done through the documented API rather than by manipulating the values in the structure.

PyTypeObject PySet_Type

Part of the Stable ABI.

이것은 파이썬 set 형을 나타내는 PyTypeObject의 인스턴스입니다.

PyTypeObject PyFrozenSet_Type

Part of the Stable ABI.

이것은 파이썬 frozenset 형을 나타내는 PyTypeObject의 인스턴스입니다.

다음 형 검사 매크로는 모든 파이썬 객체에 대한 포인터에서 작동합니다. 마찬가지로, 생성자 함수는 모든 이터러블 파이썬 객체에서 작동합니다.

int PySet_Check(PyObject *p)

p가 set 객체나 서브 형의 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyFrozenSet_Check(PyObject *p)

p가 frozenset 객체나 서브 형의 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyAnySet_Check(PyObject *p)

p가 set 객체, frozenset 객체 또는 서브 형의 인스턴스면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PySet_CheckExact(PyObject *p)

Return true if p is a set object but not an instance of a subtype. This function always succeeds.

Added in version 3.10.

int PyAnySet_CheckExact(PyObject *p)

p가 set 객체나 frozenset 객체이지만, 서브 형의 인스턴스는 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyFrozenSet_CheckExact(PyObject *p)

p가 frozenset 객체이지만, 서브 형의 인스턴스는 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PySet_New(PyObject *iterable)

Return value: New reference. Part of the Stable ABI.

iterable에 의해 반환된 객체를 포함하는 새로운 set을 반환합니다. iterable은 새로운 빈 집합을 만들기 위해 NULL 일 수 있습니다. 성공하면 새 집합을, 실패하면 NULL을 반환합니다. iterable이 실제로 이터러블이 아니면 TypeError를 발생시킵니다. 생성자는 집합을 복사할 때도 유용합니다 (c=set(s)).

PyObject *PyFrozenSet_New(PyObject *iterable)

Return value: New reference. Part of the Stable ABI.

iterable에 의해 반환된 객체를 포함한 새로운 frozenset을 반환합니다. iterable은 새로운 빈 frozenset을 만들기 위해 NULL 일 수 있습니다. 성공하면 새 집합을, 실패하면 NULL을 반환합니다. iterable이 실제로 이터러블이 아니면 TypeError를 발생시킵니다.

set 이나 frozenset의 인스턴스 또는 그들의 서브 형의 인스턴스에 대해 다음 함수와 매크로를 사용할 수 있습니다.

Py_ssize_t PySet_Size(PyObject *anyset)

Part of the Stable ABI.

Return the length of a set or frozenset object. Equivalent to len(anyset). Raises a SystemError if anyset is not a set, frozenset, or an instance of a subtype.

Py_ssize_t PySet_GET_SIZE(PyObject *anyset)

에러 검사 없는 PySet_Size()의 매크로 형식.

int PySet_Contains(PyObject *anyset, PyObject *key)

Part of the Stable ABI.

Return 1 if found, 0 if not found, and -1 if an error is encountered. Unlike the Python __contains__() method, this function does not automatically convert unhashable sets into temporary frozensets. Raise a TypeError if the key is unhashable. Raise SystemError if anyset is not a set, frozenset, or an instance of a subtype.

int PySet_Add(PyObject *set, PyObject *key)

Part of the Stable ABI.

Add key to a set instance. Also works with frozenset instances (like PyTuple_SetItem() it can be used to fill in the values of brand new frozensets before they are exposed to other code). Return 0 on success or -1 on failure. Raise a TypeError if the key is unhashable. Raise a MemoryError if there is no room to grow. Raise a SystemError if set is not an instance of set or its subtype.

다음 함수는 set 이나 그것의 서브 형의 인스턴스에는 사용할 수 있지만, frozenset 이나 그 서브 형의 인스턴스에는 사용할 수 없습니다.

int PySet_Discard(PyObject *set, PyObject *key)

Part of the Stable ABI.

Return 1 if found and removed, 0 if not found (no action taken), and -1 if an error is encountered. Does not raise KeyError for missing keys. Raise a TypeError if the key is unhashable. Unlike the Python discard() method, this function does not automatically convert unhashable sets into temporary frozensets. Raise SystemError if set is not an instance of set or its subtype.

PyObject *PySet_Pop(PyObject *set)

Return value: New reference. Part of the Stable ABI.

set에 들어있는 임의의 객체에 대한 새 참조를 반환하고, set에서 객체를 제거합니다. 실패하면 NULL을 반환합니다. 집합이 비어 있으면, KeyError를 발생시킵니다. set이 set 이나 그 서브 형의 인스턴스가 아니면 SystemError를 발생시킵니다.

int PySet_Clear(PyObject *set)

Part of the Stable ABI.

Empty an existing set of all elements. Return 0 on success. Return -1 and raise SystemError if set is not an instance of set or its subtype.

함수 객체

파이썬 함수와 관련된 몇 가지 함수가 있습니다.

type PyFunctionObject

함수에 사용되는 C 구조체.

PyTypeObject PyFunction_Type

이것은 PyTypeObject의 인스턴스이며 파이썬 함수 형을 나타냅니다. 파이썬 프로그래머에게 types.FunctionType으로 노출됩니다.

int PyFunction_Check(PyObject *o)

o가 함수 객체(PyFunction_Type 형)면 참을 반환합니다. 매개 변수는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PyFunction_New(PyObject *code, PyObject *globals)

Return value: New reference.

코드 객체 code와 연관된 새 함수 객체를 반환합니다. globals는 함수에서 액세스할 수 있는 전역 변수가 있는 딕셔너리이어야 합니다.

The function’s docstring and name are retrieved from the code object. __module__ is retrieved from globals. The argument defaults, annotations and closure are set to NULL. __qualname__ is set to the same value as the code object’s co_qualname field.

PyObject *PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname)

Return value: New reference.

As PyFunction_New(), but also allows setting the function object’s __qualname__ attribute. qualname should be a unicode object or NULL; if NULL, the __qualname__ attribute is set to the same value as the code object’s co_qualname field.

Added in version 3.3.

PyObject *PyFunction_GetCode(PyObject *op)

Return value: Borrowed reference.

함수 객체 op와 연관된 코드 객체를 반환합니다.

PyObject *PyFunction_GetGlobals(PyObject *op)

Return value: Borrowed reference.

함수 객체 op와 연관된 전역 딕셔너리를 반환합니다.

PyObject *PyFunction_GetModule(PyObject *op)

Return value: Borrowed reference.

Return a borrowed reference to the __module__ attribute of the function object op. It can be NULL.

This is normally a string containing the module name, but can be set to any other object by Python code.

PyObject *PyFunction_GetDefaults(PyObject *op)

Return value: Borrowed reference.

함수 객체 op의 인자 기본값을 반환합니다. 이는 인자의 튜플이나 NULL일 수 있습니다.

int PyFunction_SetDefaults(PyObject *op, PyObject *defaults)

함수 객체 op의 인자 기본값을 설정합니다. defaults는 Py_None 이나 튜플이어야 합니다.

실패하면 SystemError를 발생시키고 -1을 반환합니다.

void PyFunction_SetVectorcall(PyFunctionObject *func, vectorcallfunc vectorcall)

Set the vectorcall field of a given function object func.

Warning: extensions using this API must preserve the behavior of the unaltered (default) vectorcall function!

Added in version 3.12.

PyObject *PyFunction_GetClosure(PyObject *op)

Return value: Borrowed reference.

함수 객체 op와 연관된 클로저를 반환합니다. 이것은 NULL 이나 셀 객체의 튜플일 수 있습니다.

int PyFunction_SetClosure(PyObject *op, PyObject *closure)

함수 객체 op와 연관된 클로저를 설정합니다. closure는 Py_None 이나 셀 객체의 튜플이어야 합니다.

실패하면 SystemError를 발생시키고 -1을 반환합니다.

PyObject *PyFunction_GetAnnotations(PyObject *op)

Return value: Borrowed reference.

함수 객체 op의 어노테이션을 반환합니다. 이것은 가변 딕셔너리나 NULL 일 수 있습니다.

int PyFunction_SetAnnotations(PyObject *op, PyObject *annotations)

함수 객체 op의 어노테이션을 설정합니다. annotations은 딕셔너리나 Py_None 이어야 합니다.

실패하면 SystemError를 발생시키고 -1을 반환합니다.

int PyFunction_AddWatcher(PyFunction_WatchCallback callback)

Register callback as a function watcher for the current interpreter. Return an ID which may be passed to PyFunction_ClearWatcher(). In case of error (e.g. no more watcher IDs available), return -1 and set an exception.

Added in version 3.12.

int PyFunction_ClearWatcher(int watcher_id)

Clear watcher identified by watcher_id previously returned from PyFunction_AddWatcher() for the current interpreter. Return 0 on success, or -1 and set an exception on error (e.g. if the given watcher_id was never registered.)

Added in version 3.12.

type PyFunction_WatchEvent

Enumeration of possible function watcher events: - PyFunction_EVENT_CREATE - PyFunction_EVENT_DESTROY - PyFunction_EVENT_MODIFY_CODE - PyFunction_EVENT_MODIFY_DEFAULTS - PyFunction_EVENT_MODIFY_KWDEFAULTS

Added in version 3.12.

typedef int (*PyFunction_WatchCallback)(PyFunction_WatchEvent event, PyFunctionObject *func, PyObject *new_value)

Type of a function watcher callback function.

If event is PyFunction_EVENT_CREATE or PyFunction_EVENT_DESTROY then new_value will be NULL. Otherwise, new_value will hold a borrowed reference to the new value that is about to be stored in func for the attribute that is being modified.

The callback may inspect but must not modify func; doing so could have unpredictable effects, including infinite recursion.

If event is PyFunction_EVENT_CREATE, then the callback is invoked after func has been fully initialized. Otherwise, the callback is invoked before the modification to func takes place, so the prior state of func can be inspected. The runtime is permitted to optimize away the creation of function objects when possible. In such cases no event will be emitted. Although this creates the possibility of an observable difference of runtime behavior depending on optimization decisions, it does not change the semantics of the Python code being executed.

If event is PyFunction_EVENT_DESTROY, Taking a reference in the callback to the about-to-be-destroyed function will resurrect it, preventing it from being freed at this time. When the resurrected object is destroyed later, any watcher callbacks active at that time will be called again.

If the callback sets an exception, it must return -1; this exception will be printed as an unraisable exception using PyErr_WriteUnraisable(). Otherwise it should return 0.

There may already be a pending exception set on entry to the callback. In this case, the callback should return 0 with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.

Added in version 3.12.

인스턴스 메서드 객체

An instance method is a wrapper for a PyCFunction and the new way to bind a PyCFunction to a class object. It replaces the former call PyMethod_New(func, NULL, class).

PyTypeObject PyInstanceMethod_Type

이 PyTypeObject 인스턴스는 파이썬 인스턴스 메서드 형을 나타냅니다. 파이썬 프로그램에는 노출되지 않습니다.

int PyInstanceMethod_Check(PyObject *o)

o가 인스턴스 메서드 객체면 참을 반환합니다 (PyInstanceMethod_Type 형입니다). 매개 변수는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PyInstanceMethod_New(PyObject *func)

Return value: New reference.

Return a new instance method object, with func being any callable object. func is the function that will be called when the instance method is called.

PyObject *PyInstanceMethod_Function(PyObject *im)

Return value: Borrowed reference.

인스턴스 메서드 im과 연관된 함수 객체를 반환합니다.

PyObject *PyInstanceMethod_GET_FUNCTION(PyObject *im)

Return value: Borrowed reference.

오류 검사를 피하는 PyInstanceMethod_Function()의 매크로 버전.

메서드 객체

메서드는 연결된(bound) 함수 객체입니다. 메서드는 항상 사용자 정의 클래스의 인스턴스에 연결됩니다. 연결되지 않은(unbound) 메서드(클래스 객체에 연결된 메서드)는 더는 사용할 수 없습니다.

PyTypeObject PyMethod_Type

이 PyTypeObject 인스턴스는 파이썬 메서드 형을 나타냅니다. 이것은 파이썬 프로그램에 types.MethodType로 노출됩니다.

int PyMethod_Check(PyObject *o)

o가 메서드 객체면 참을 반환합니다 (PyMethod_Type 형입니다). 매개 변수는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PyMethod_New(PyObject *func, PyObject *self)

Return value: New reference.

새로운 메서드 객체를 돌려줍니다. func는 임의의 콜러블 객체이며, self는 메서드가 연결되어야 할 인스턴스입니다. func는 메서드가 호출될 때 호출될 함수입니다. self는 NULL이 아니어야 합니다.

PyObject *PyMethod_Function(PyObject *meth)

Return value: Borrowed reference.

meth 메서드와 연관된 함수 객체를 반환합니다.

PyObject *PyMethod_GET_FUNCTION(PyObject *meth)

Return value: Borrowed reference.

오류 검사를 피하는 PyMethod_Function()의 매크로 버전.

PyObject *PyMethod_Self(PyObject *meth)

Return value: Borrowed reference.

meth 메서드와 연관된 인스턴스를 반환합니다.

PyObject *PyMethod_GET_SELF(PyObject *meth)

Return value: Borrowed reference.

오류 검사를 피하는 PyMethod_Self()의 매크로 버전.

셀 객체

“셀” 객체는 여러 스코프에서 참조하는 변수를 구현하는 데 사용됩니다. 이러한 변수마다, 값을 저장하기 위해 셀 객체가 만들어집니다; 값을 참조하는 각 스택 프레임의 지역 변수에는 해당 변수를 사용하는 외부 스코프의 셀에 대한 참조가 포함됩니다. 값에 액세스하면, 셀 객체 자체 대신 셀에 포함된 값이 사용됩니다. 이러한 셀 객체의 역참조(de-referencing)는 생성된 바이트 코드로부터의 지원이 필요합니다; 액세스 시 자동으로 역참조되지 않습니다. 셀 객체는 다른 곳에 유용하지는 않습니다.

type PyCellObject

셀 객체에 사용되는 C 구조체.

PyTypeObject PyCell_Type

셀 객체에 해당하는 형 객체.

int PyCell_Check(PyObject *ob)

ob가 셀 객체면 참을 반환합니다; ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PyCell_New(PyObject *ob)

Return value: New reference.

ob 값을 포함하는 새 셀 객체를 만들고 반환합니다. 매개 변수는 NULL 일 수 있습니다.

PyObject *PyCell_Get(PyObject *cell)

Return value: New reference.

Return the contents of the cell cell, which can be NULL. If cell is not a cell object, returns NULL with an exception set.

PyObject *PyCell_GET(PyObject *cell)

Return value: Borrowed reference.

셀 cell의 내용을 반환하지만, cell이 NULL이 아닌지와 셀 객체인지를 확인하지 않습니다.

int PyCell_Set(PyObject *cell, PyObject *value)

Set the contents of the cell object cell to value. This releases the reference to any current content of the cell. value may be NULL. cell must be non-NULL.

On success, return 0. If cell is not a cell object, set an exception and return -1.

void PyCell_SET(PyObject *cell, PyObject *value)

셀 객체 cell의 값을 value로 설정합니다. 참조 횟수는 조정되지 않고, 안전을 위한 검사가 이루어지지 않습니다; cell은 NULL이 아니어야 하고 셀 객체여야 합니다.

코드 객체

코드 객체는 CPython 구현의 저수준 세부 사항입니다. 각 객체는 아직 함수에 묶여 있지 않은 실행 가능한 코드 덩어리를 나타냅니다.

type PyCodeObject

코드 객체를 설명하는 데 사용되는 객체의 C 구조체. 이 형의 필드는 언제든지 변경될 수 있습니다.

PyTypeObject PyCode_Type

This is an instance of PyTypeObject representing the Python code object.

int PyCode_Check(PyObject *co)

Return true if co is a code object. This function always succeeds.

Py_ssize_t PyCode_GetNumFree(PyCodeObject *co)

Return the number of free (closure) variables in a code object.

int PyUnstable_Code_GetFirstFree(PyCodeObject *co)

This is Unstable API. It may change without warning in minor releases.

Return the position of the first free (closure) variable in a code object.

버전 3.13에서 변경: Renamed from PyCode_GetFirstFree as part of Unstable C API. The old name is deprecated, but will remain available until the signature changes again.

PyCodeObject *PyUnstable_Code_New(int argcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, PyObject *qualname, int firstlineno, PyObject *linetable, PyObject *exceptiontable)

This is Unstable API. It may change without warning in minor releases.

Return a new code object. If you need a dummy code object to create a frame, use PyCode_NewEmpty() instead.

Since the definition of the bytecode changes often, calling PyUnstable_Code_New() directly can bind you to a precise Python version.

The many arguments of this function are inter-dependent in complex ways, meaning that subtle changes to values are likely to result in incorrect execution or VM crashes. Use this function only with extreme care.

버전 3.11에서 변경: Added qualname and exceptiontable parameters.

버전 3.12에서 변경: Renamed from PyCode_New as part of Unstable C API. The old name is deprecated, but will remain available until the signature changes again.

PyCodeObject *PyUnstable_Code_NewWithPosOnlyArgs(int argcount, int posonlyargcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, PyObject *qualname, int firstlineno, PyObject *linetable, PyObject *exceptiontable)

This is Unstable API. It may change without warning in minor releases.

Similar to PyUnstable_Code_New(), but with an extra “posonlyargcount” for positional-only arguments. The same caveats that apply to PyUnstable_Code_New also apply to this function.

Added in version 3.8: as PyCode_NewWithPosOnlyArgs

버전 3.11에서 변경: Added qualname and exceptiontable parameters.

버전 3.12에서 변경: Renamed to PyUnstable_Code_NewWithPosOnlyArgs. The old name is deprecated, but will remain available until the signature changes again.

PyCodeObject *PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)

Return value: New reference.

Return a new empty code object with the specified filename, function name, and first line number. The resulting code object will raise an Exception if executed.

int PyCode_Addr2Line(PyCodeObject *co, int byte_offset)

Return the line number of the instruction that occurs on or before byte_offset and ends after it. If you just need the line number of a frame, use PyFrame_GetLineNumber() instead.

For efficiently iterating over the line numbers in a code object, use the API described in PEP 626 [https://peps.python.org/pep-0626/#out-of-process-debuggers-and-profilers].

int PyCode_Addr2Location(PyObject *co, int byte_offset, int *start_line, int *start_column, int *end_line, int *end_column)

Sets the passed int pointers to the source code line and column numbers for the instruction at byte_offset. Sets the value to 0 when information is not available for any particular element.

Returns 1 if the function succeeds and 0 otherwise.

Added in version 3.11.

PyObject *PyCode_GetCode(PyCodeObject *co)

Equivalent to the Python code getattr(co, 'co_code'). Returns a strong reference to a PyBytesObject representing the bytecode in a code object. On error, NULL is returned and an exception is raised.

This PyBytesObject may be created on-demand by the interpreter and does not necessarily represent the bytecode actually executed by CPython. The primary use case for this function is debuggers and profilers.

Added in version 3.11.

PyObject *PyCode_GetVarnames(PyCodeObject *co)

Equivalent to the Python code getattr(co, 'co_varnames'). Returns a new reference to a PyTupleObject containing the names of the local variables. On error, NULL is returned and an exception is raised.

Added in version 3.11.

PyObject *PyCode_GetCellvars(PyCodeObject *co)

Equivalent to the Python code getattr(co, 'co_cellvars'). Returns a new reference to a PyTupleObject containing the names of the local variables that are referenced by nested functions. On error, NULL is returned and an exception is raised.

Added in version 3.11.

PyObject *PyCode_GetFreevars(PyCodeObject *co)

Equivalent to the Python code getattr(co, 'co_freevars'). Returns a new reference to a PyTupleObject containing the names of the free (closure) variables. On error, NULL is returned and an exception is raised.

Added in version 3.11.

int PyCode_AddWatcher(PyCode_WatchCallback callback)

Register callback as a code object watcher for the current interpreter. Return an ID which may be passed to PyCode_ClearWatcher(). In case of error (e.g. no more watcher IDs available), return -1 and set an exception.

Added in version 3.12.

int PyCode_ClearWatcher(int watcher_id)

Clear watcher identified by watcher_id previously returned from PyCode_AddWatcher() for the current interpreter. Return 0 on success, or -1 and set an exception on error (e.g. if the given watcher_id was never registered.)

Added in version 3.12.

type PyCodeEvent

Enumeration of possible code object watcher events: - PY_CODE_EVENT_CREATE - PY_CODE_EVENT_DESTROY

Added in version 3.12.

typedef int (*PyCode_WatchCallback)(PyCodeEvent event, PyCodeObject *co)

Type of a code object watcher callback function.

If event is PY_CODE_EVENT_CREATE, then the callback is invoked after co has been fully initialized. Otherwise, the callback is invoked before the destruction of co takes place, so the prior state of co can be inspected.

If event is PY_CODE_EVENT_DESTROY, taking a reference in the callback to the about-to-be-destroyed code object will resurrect it and prevent it from being freed at this time. When the resurrected object is destroyed later, any watcher callbacks active at that time will be called again.

Users of this API should not rely on internal runtime implementation details. Such details may include, but are not limited to, the exact order and timing of creation and destruction of code objects. While changes in these details may result in differences observable by watchers (including whether a callback is invoked or not), it does not change the semantics of the Python code being executed.

If the callback sets an exception, it must return -1; this exception will be printed as an unraisable exception using PyErr_WriteUnraisable(). Otherwise it should return 0.

There may already be a pending exception set on entry to the callback. In this case, the callback should return 0 with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.

Added in version 3.12.

Extra information

To support low-level extensions to frame evaluation, such as external just-in-time compilers, it is possible to attach arbitrary extra data to code objects.

These functions are part of the unstable C API tier: this functionality is a CPython implementation detail, and the API may change without deprecation warnings.

Py_ssize_t PyUnstable_Eval_RequestCodeExtraIndex(freefunc free)

This is Unstable API. It may change without warning in minor releases.

Return a new an opaque index value used to adding data to code objects.

You generally call this function once (per interpreter) and use the result with PyCode_GetExtra and PyCode_SetExtra to manipulate data on individual code objects.

If free is not NULL: when a code object is deallocated, free will be called on non-NULL data stored under the new index. Use Py_DecRef() when storing PyObject.

Added in version 3.6: as _PyEval_RequestCodeExtraIndex

버전 3.12에서 변경: Renamed to PyUnstable_Eval_RequestCodeExtraIndex. The old private name is deprecated, but will be available until the API changes.

int PyUnstable_Code_GetExtra(PyObject *code, Py_ssize_t index, void **extra)

This is Unstable API. It may change without warning in minor releases.

Set extra to the extra data stored under the given index. Return 0 on success. Set an exception and return -1 on failure.

If no data was set under the index, set extra to NULL and return 0 without setting an exception.

Added in version 3.6: as _PyCode_GetExtra

버전 3.12에서 변경: Renamed to PyUnstable_Code_GetExtra. The old private name is deprecated, but will be available until the API changes.

int PyUnstable_Code_SetExtra(PyObject *code, Py_ssize_t index, void *extra)

This is Unstable API. It may change without warning in minor releases.

Set the extra data stored under the given index to extra. Return 0 on success. Set an exception and return -1 on failure.

Added in version 3.6: as _PyCode_SetExtra

버전 3.12에서 변경: Renamed to PyUnstable_Code_SetExtra. The old private name is deprecated, but will be available until the API changes.

파일 객체

These APIs are a minimal emulation of the Python 2 C API for built-in file objects, which used to rely on the buffered I/O (FILE*) support from the C standard library. In Python 3, files and streams use the new io module, which defines several layers over the low-level unbuffered I/O of the operating system. The functions described below are convenience C wrappers over these new APIs, and meant mostly for internal error reporting in the interpreter; third-party code is advised to access the io APIs instead.

PyObject *PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding, const char *errors, const char *newline, int closefd)

Return value: New reference. Part of the Stable ABI.

이미 열려있는 파일의 파일 기술자 fd로 파이썬 파일 객체를 만듭니다. 인자 name, encoding, errors 및 newline은 기본값을 사용하기 위해 NULL 일 수 있습니다; buffering은 기본값을 사용하기 위해 -1 일 수 있습니다. name은 무시되고, 이전 버전과의 호환성을 위해 유지됩니다. 실패 시 NULL을 반환합니다. 인자에 대한 더 자세한 설명은 io.open() 함수 설명서를 참조하십시오.

경고

파이썬 스트림이 자체적인 버퍼링 계층을 가지고 있으므로, OS 수준의 파일 기술자와 혼합하면 여러 예기치 못한 문제가 발생할 수 있습니다 (가령 데이터의 예상치 못한 순서).

버전 3.2에서 변경: name 어트리뷰트를 무시합니다.

int PyObject_AsFileDescriptor(PyObject *p)

Part of the Stable ABI.

Return the file descriptor associated with p as an int. If the object is an integer, its value is returned. If not, the object’s fileno() method is called if it exists; the method must return an integer, which is returned as the file descriptor value. Sets an exception and returns -1 on failure.

PyObject *PyFile_GetLine(PyObject *p, int n)

Return value: New reference. Part of the Stable ABI.

p.readline([n])과 동등합니다. 이 함수는 객체 p에서 한 줄을 읽습니다. p는 파일 객체나 readline() 메서드가 있는 임의의 객체일 수 있습니다. n이 0이면, 줄의 길이와 관계없이 정확히 한 줄을 읽습니다. n이 0보다 크면, n 바이트 이상을 파일에서 읽지 않습니다; 불완전한 줄이 반환될 수 있습니다. 두 경우 모두, 파일 끝에 즉시 도달하면 빈 문자열이 반환됩니다. 그러나 n이 0보다 작으면, 길이와 관계없이 한 줄을 읽지만, 파일 끝에 즉시 도달하면 EOFError가 발생합니다.

int PyFile_SetOpenCodeHook(Py_OpenCodeHookFunction handler)

제공된 handler를 통해 매개 변수를 전달하도록 io.open_code()의 일반적인 동작을 재정의합니다.

The handler is a function of type:

typedef PyObject *(*Py_OpenCodeHookFunction)(PyObject*, void*)

Equivalent of PyObject *(*)(PyObject *path, void *userData), where path is guaranteed to be PyUnicodeObject.

userData 포인터는 훅 함수로 전달됩니다. 훅 함수는 다른 런타임에서 호출될 수 있으므로, 이 포인터는 파이썬 상태를 직접 참조하면 안 됩니다.

이 훅은 의도적으로 임포트 중에 사용되므로, 고정되었거나(frozen) sys.modules에 있다고 알려진 경우가 아니라면 훅 실행 중에 새로운 모듈을 임포트하는 것을 피하십시오.

일단 훅이 설정되면, 제거하거나 교체할 수 없으며, 이후의 PyFile_SetOpenCodeHook()에 대한 호출은 실패합니다. 실패 시, 함수는 -1을 반환하고 인터프리터가 초기화되었으면 예외를 설정합니다.

이 함수는 Py_Initialize() 전에 호출해도 안전합니다.

인자 없이 감사 이벤트 setopencodehook을 발생시킵니다.

Added in version 3.8.

int PyFile_WriteObject(PyObject *obj, PyObject *p, int flags)

Part of the Stable ABI.

Write object obj to file object p. The only supported flag for flags is Py_PRINT_RAW; if given, the str() of the object is written instead of the repr(). Return 0 on success or -1 on failure; the appropriate exception will be set.

int PyFile_WriteString(const char *s, PyObject *p)

Part of the Stable ABI.

문자열 s를 파일 객체 p에 씁니다. 성공하면 0을 반환하고, 실패하면 -1을 반환합니다; 적절한 예외가 설정됩니다.

모듈 객체

PyTypeObject PyModule_Type

Part of the Stable ABI.

이 PyTypeObject 인스턴스는 파이썬 모듈 형을 나타냅니다. 이것은 types.ModuleType으로 파이썬 프로그램에 노출됩니다.

int PyModule_Check(PyObject *p)

p가 모듈 객체이거나 모듈 객체의 서브 형이면 참을 반환합니다. 이 함수는 항상 성공합니다.

int PyModule_CheckExact(PyObject *p)

p가 모듈 객체이지만, PyModule_Type의 서브 형이 아니면 참을 반환합니다. 이 함수는 항상 성공합니다.

PyObject *PyModule_NewObject(PyObject *name)

Return value: New reference. Part of the Stable ABI since version 3.7.

Return a new module object with module.__name__ set to name. The module’s __name__, __doc__, __package__ and __loader__ attributes are filled in (all but __name__ are set to None). The caller is responsible for setting a __file__ attribute.

Return NULL with an exception set on error.

Added in version 3.3.

버전 3.4에서 변경: __package__ and __loader__ are now set to None.

PyObject *PyModule_New(const char *name)

Return value: New reference. Part of the Stable ABI.

PyModule_NewObject()와 비슷하지만, name이 유니코드 객체 대신 UTF-8로 인코딩된 문자열입니다.

PyObject *PyModule_GetDict(PyObject *module)

Return value: Borrowed reference. Part of the Stable ABI.

module의 이름 공간을 구현하는 딕셔너리 객체를 반환합니다; 이 객체는 모듈 객체의 __dict__ 어트리뷰트와 같습니다. module이 모듈 객체(또는 모듈 객체의 서브 형)가 아니면, SystemError가 발생하고 NULL이 반환됩니다.

It is recommended extensions use other PyModule_* and PyObject_* functions rather than directly manipulate a module’s __dict__.

PyObject *PyModule_GetNameObject(PyObject *module)

Return value: New reference. Part of the Stable ABI since version 3.7.

Return module’s __name__ value. If the module does not provide one, or if it is not a string, SystemError is raised and NULL is returned.

Added in version 3.3.

const char *PyModule_GetName(PyObject *module)

Part of the Stable ABI.

PyModule_GetNameObject()와 비슷하지만 'utf-8'로 인코딩된 이름을 반환합니다.

void *PyModule_GetState(PyObject *module)

Part of the Stable ABI.

모듈의 “상태”, 즉 모듈 생성 시 할당된 메모리 블록을 가리키는 포인터나 NULL을 반환합니다. PyModuleDef.m_size를 참조하십시오.

PyModuleDef *PyModule_GetDef(PyObject *module)

Part of the Stable ABI.

모듈이 만들어진 PyModuleDef 구조체에 대한 포인터나 모듈이 정의에서 만들어지지 않았으면 NULL을 반환합니다.

PyObject *PyModule_GetFilenameObject(PyObject *module)

Return value: New reference. Part of the Stable ABI.

Return the name of the file from which module was loaded using module’s __file__ attribute. If this is not defined, or if it is not a string, raise SystemError and return NULL; otherwise return a reference to a Unicode object.

Added in version 3.2.

const char *PyModule_GetFilename(PyObject *module)

Part of the Stable ABI.

PyModule_GetFilenameObject()와 비슷하지만 ‘utf-8’로 인코딩된 파일명을 반환합니다.

버전 3.2부터 폐지됨: PyModule_GetFilename() raises UnicodeEncodeError on unencodable filenames, use PyModule_GetFilenameObject() instead.

C 모듈 초기화

모듈 객체는 일반적으로 확장 모듈(초기화 함수를 내보내는 공유 라이브러리)이나 컴파일된 모듈(초기화 함수가 PyImport_AppendInittab()을 사용하여 추가된)에서 만들어집니다. 자세한 내용은 C와 C++ 확장 빌드하기나 내장된 파이썬을 확장하기를 참조하십시오.

초기화 함수는 모듈 정의 인스턴스를 PyModule_Create()에 전달하고 결과 모듈 객체를 반환하거나, 정의 구조체 자체를 반환하여 “다단계 초기화”를 요청할 수 있습니다.

type PyModuleDef

Part of the Stable ABI (including all members).

모듈 객체를 만드는 데 필요한 모든 정보를 담고 있는 모듈 정의 구조체. 일반적으로 각 모듈에 대해 이 형의 정적으로 초기화된 변수가 하나만 있습니다.

PyModuleDef_Base m_base

Always initialize this member to PyModuleDef_HEAD_INIT.

const char *m_name

새 모듈의 이름.

const char *m_doc

모듈의 독스트링; 일반적으로 PyDoc_STRVAR로 만들어진 독스트링 변수가 사용됩니다.

Py_ssize_t m_size

모듈 상태는 정적 전역이 아닌 PyModule_GetState()로 조회할 수 있는 모듈별 메모리 영역에 유지될 수 있습니다. 이것은 여러 서브 인터프리터에서 모듈을 사용하는 것을 안전하게 만듭니다.

This memory area is allocated based on m_size on module creation, and freed when the module object is deallocated, after the m_free function has been called, if present.

m_size를 -1로 설정하면 모듈이 전역 상태를 갖기 때문에 서브 인터프리터를 지원하지 않는다는 뜻입니다.

음수가 아닌 값으로 설정하면 모듈을 다시 초기화 할 수 있다는 뜻이며 상태에 필요한 추가 메모리양을 지정합니다. 다단계 초기화에는 음이 아닌 m_size가 필요합니다.

자세한 내용은 PEP 3121 [https://peps.python.org/pep-3121/]을 참조하십시오.

PyMethodDef *m_methods

PyMethodDef 값으로 기술되는 모듈 수준 함수 테이블에 대한 포인터. 함수가 없으면 NULL일 수 있습니다.

PyModuleDef_Slot *m_slots

다단계 초기화를 위한 슬롯 정의 배열, {0, NULL} 항목으로 종료됩니다. 단단계 초기화를 사용할 때, m_slots는 NULL이어야 합니다.

버전 3.5에서 변경: 버전 3.5 이전에는, 이 멤버가 항상 NULL로 설정되었으며, 다음과 같이 정의되었습니다:

inquiry m_reload

traverseproc m_traverse

모듈 객체의 GC 탐색 중 호출할 탐색 함수나, 필요하지 않으면 NULL.

This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec function). More precisely, this function is not called if m_size is greater than 0 and the module state (as returned by PyModule_GetState()) is NULL.

버전 3.9에서 변경: 모듈 상태가 할당되기 전에 더는 호출되지 않습니다.

inquiry m_clear

모듈 객체의 GC 정리 중에 호출할 정리(clear) 함수나, 필요하지 않으면 NULL.

This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec function). More precisely, this function is not called if m_size is greater than 0 and the module state (as returned by PyModule_GetState()) is NULL.

Like PyTypeObject.tp_clear, this function is not always called before a module is deallocated. For example, when reference counting is enough to determine that an object is no longer used, the cyclic garbage collector is not involved and m_free is called directly.

버전 3.9에서 변경: 모듈 상태가 할당되기 전에 더는 호출되지 않습니다.

freefunc m_free

모듈 객체 할당 해제 중에 호출할 함수나, 필요하지 않으면 NULL.

This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec function). More precisely, this function is not called if m_size is greater than 0 and the module state (as returned by PyModule_GetState()) is NULL.

버전 3.9에서 변경: 모듈 상태가 할당되기 전에 더는 호출되지 않습니다.

단단계 초기화

모듈 초기화 함수는 모듈 객체를 직접 만들고 반환할 수 있습니다. 이것을 “단단계 초기화”라고 하며, 다음 두 모듈 생성 함수 중 하나를 사용합니다:

PyObject *PyModule_Create(PyModuleDef *def)

Return value: New reference.

Create a new module object, given the definition in def. This behaves like PyModule_Create2() with module_api_version set to PYTHON_API_VERSION.

PyObject *PyModule_Create2(PyModuleDef *def, int module_api_version)

Return value: New reference. Part of the Stable ABI.

def의 정의에 따라, API 버전 module_api_version을 가정하여 새 모듈 객체를 만듭니다. 해당 버전이 실행 중인 인터프리터 버전과 일치하지 않으면, RuntimeWarning을 발생시킵니다.

Return NULL with an exception set on error.

참고

이 함수는 대부분 PyModule_Create()를 대신 사용해야 합니다; 확실히 필요할 때만 사용하십시오.

Before it is returned from in the initialization function, the resulting module object is typically populated using functions like PyModule_AddObjectRef().

다단계 초기화

An alternate way to specify extensions is to request “multi-phase initialization”. Extension modules created this way behave more like Python modules: the initialization is split between the creation phase, when the module object is created, and the execution phase, when it is populated. The distinction is similar to the __new__() and __init__() methods of classes.

Unlike modules created using single-phase initialization, these modules are not singletons: if the sys.modules entry is removed and the module is re-imported, a new module object is created, and the old module is subject to normal garbage collection – as with Python modules. By default, multiple modules created from the same definition should be independent: changes to one should not affect the others. This means that all state should be specific to the module object (using e.g. using PyModule_GetState()), or its contents (such as the module’s __dict__ or individual classes created with PyType_FromSpec()).

다단계 초기화를 사용하여 만들어진 모든 모듈은 서브 인터프리터를 지원할 것으로 기대됩니다. 다중 모듈을 독립적으로 유지하는 것은 일반적으로 이를 달성하기에 충분합니다.

다단계 초기화를 요청하기 위해, 초기화 함수(PyInit_modulename)는 비어 있지 않은 m_slots를 가진 PyModuleDef 인스턴스를 반환합니다. 반환되기 전에, PyModuleDef 인스턴스를 다음 함수를 사용하여 초기화해야 합니다:

PyObject *PyModuleDef_Init(PyModuleDef *def)

Return value: Borrowed reference. Part of the Stable ABI since version 3.5.

모듈 정의가 형과 참조 횟수를 올바르게 보고하는 올바르게 초기화된 파이썬 객체이게 합니다.

def를 PyObject*로 캐스트 하거나, 에러가 발생하면 NULL을 반환합니다.

Added in version 3.5.

모듈 정의의 m_slots 멤버는 PyModuleDef_Slot 구조체의 배열을 가리켜야 합니다:

type PyModuleDef_Slot

int slot

아래 설명된 사용 가능한 값 중에서 선택된, 슬롯 ID.

void *value

슬롯 ID에 따라 그 의미가 달라지는, 슬롯의 값.

Added in version 3.5.

m_slots 배열은 id가 0인 슬롯으로 종료해야 합니다.

사용 가능한 슬롯 형은 다음과 같습니다:

Py_mod_create

모듈 객체 자체를 만들기 위해 호출되는 함수를 지정합니다. 이 슬롯의 value 포인터는 다음과 같은 서명을 갖는 함수를 가리켜야 합니다:

PyObject *create_module(PyObject *spec, PyModuleDef *def)

이 함수는 PEP 451 [https://peps.python.org/pep-0451/]에 정의된 대로, ModuleSpec 인스턴스와 모듈 정의를 받습니다. 새 모듈 객체를 반환하거나, 에러를 설정하고 NULL을 반환해야 합니다.

이 함수는 최소한으로 유지해야 합니다. 특히 같은 모듈을 다시 임포트 하려고 시도하면 무한 루프가 발생할 수 있어서, 임의의 파이썬 코드를 호출하면 안 됩니다.

하나의 모듈 정의에서 여러 Py_mod_create 슬롯을 지정할 수 없습니다.

Py_mod_create를 지정하지 않으면, 임포트 절차는 PyModule_New()를 사용하여 일반 모듈 객체를 만듭니다. 이름은 정의가 아니라 spec에서 취합니다, 확장 모듈이 단일 모듈 정의를 공유하면서 모듈 계층 구조에서 해당 위치에 동적으로 조정되고 심볼릭 링크를 통해 다른 이름으로 임포트 될 수 있도록 하기 위함입니다.

반환된 객체가 PyModule_Type의 인스턴스 일 필요는 없습니다. 임포트 관련 어트리뷰트 설정과 읽기를 지원하는 한 모든 형을 사용할 수 있습니다. 그러나, PyModuleDef에 NULL이 아닌 m_traverse, m_clear, m_free; 0이 아닌 m_size; 또는 Py_mod_create 이외의 슬롯이 있으면, PyModule_Type 인스턴스 만 반환될 수 있습니다.

Py_mod_exec

모듈을 실행하기 위해 호출되는 함수를 지정합니다. 이것은 파이썬 모듈의 코드를 실행하는 것과 동등합니다: 일반적으로, 이 함수는 클래스와 상수를 모듈에 추가합니다. 함수의 서명은 다음과 같습니다:

int exec_module(PyObject *module)

여러 개의 Py_mod_exec 슬롯이 지정되면, m_slots 배열에 나타나는 순서대로 처리됩니다.

Py_mod_multiple_interpreters

Specifies one of the following values:

Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED

The module does not support being imported in subinterpreters.

Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED

The module supports being imported in subinterpreters, but only when they share the main interpreter’s GIL. (See Isolating Extension Modules.)

Py_MOD_PER_INTERPRETER_GIL_SUPPORTED

The module supports being imported in subinterpreters, even when they have their own GIL. (See Isolating Extension Modules.)

This slot determines whether or not importing this module in a subinterpreter will fail.

Multiple Py_mod_multiple_interpreters slots may not be specified in one module definition.

If Py_mod_multiple_interpreters is not specified, the import machinery defaults to Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED.

Added in version 3.12.

Py_mod_gil

Specifies one of the following values:

Py_MOD_GIL_USED

The module depends on the presence of the global interpreter lock (GIL), and may access global state without synchronization.

Py_MOD_GIL_NOT_USED

The module is safe to run without an active GIL.

This slot is ignored by Python builds not configured with --disable-gil. Otherwise, it determines whether or not importing this module will cause the GIL to be automatically enabled. See Free-threaded CPython for more detail.

Multiple Py_mod_gil slots may not be specified in one module definition.

If Py_mod_gil is not specified, the import machinery defaults to Py_MOD_GIL_USED.

Added in version 3.13.

다단계 초기화에 대한 자세한 내용은 PEP 489 [https://peps.python.org/pep-0489/]를 참조하십시오.

저수준 모듈 생성 함수

다단계 초기화를 사용할 때 수면 아래에서는 다음 함수가 호출됩니다. 이들은 직접 사용할 수 있는데, 예를 들어 모듈 객체를 동적으로 생성할 때 그렇습니다. 모듈을 완전히 초기화하려면 PyModule_FromDefAndSpec과 PyModule_ExecDef를 모두 호출해야 함에 유의하십시오.

PyObject *PyModule_FromDefAndSpec(PyModuleDef *def, PyObject *spec)

Return value: New reference.

Create a new module object, given the definition in def and the ModuleSpec spec. This behaves like PyModule_FromDefAndSpec2() with module_api_version set to PYTHON_API_VERSION.

Added in version 3.5.

PyObject *PyModule_FromDefAndSpec2(PyModuleDef *def, PyObject *spec, int module_api_version)

Return value: New reference. Part of the Stable ABI since version 3.7.

Create a new module object, given the definition in def and the ModuleSpec spec, assuming the API version module_api_version. If that version does not match the version of the running interpreter, a RuntimeWarning is emitted.

Return NULL with an exception set on error.

참고

이 함수는 대부분 PyModule_FromDefAndSpec()을 대신 사용해야 합니다; 확실히 필요할 때만 사용하십시오.

Added in version 3.5.

int PyModule_ExecDef(PyObject *module, PyModuleDef *def)

Part of the Stable ABI since version 3.7.

def에 지정된 모든 실행 슬롯(Py_mod_exec)을 처리합니다.

Added in version 3.5.

int PyModule_SetDocString(PyObject *module, const char *docstring)

Part of the Stable ABI since version 3.7.

module의 독스트링을 docstring으로 설정합니다. 이 함수는 PyModule_Create나 PyModule_FromDefAndSpec을 사용하여 PyModuleDef에서 모듈을 만들 때 자동으로 호출됩니다.

Added in version 3.5.

int PyModule_AddFunctions(PyObject *module, PyMethodDef *functions)

Part of the Stable ABI since version 3.7.

NULL 종료 functions 배열의 함수를 module에 추가합니다. 개별 항목에 대한 자세한 내용은 PyMethodDef 설명서를 참조하십시오 (공유 모듈 이름 공간이 없기 때문에, C로 구현된 모듈 수준 “함수(functions)”는 일반적으로 첫 번째 매개 변수로 모듈을 수신하여, 파이썬 클래스의 인스턴스 메서드와 유사하게 만듭니다). 이 함수는 PyModule_Create나 PyModule_FromDefAndSpec을 사용하여 PyModuleDef에서 모듈을 만들 때 자동으로 호출됩니다.

Added in version 3.5.

지원 함수

모듈 초기화 함수(단단계 초기화를 사용하는 경우)나 모듈 실행 슬롯에서 호출되는 함수(다단계 초기화를 사용하는 경우)는, 모듈 상태 초기화를 도우려고 다음 함수를 사용할 수 있습니다:

int PyModule_AddObjectRef(PyObject *module, const char *name, PyObject *value)

Part of the Stable ABI since version 3.10.

Add an object to module as name. This is a convenience function which can be used from the module’s initialization function.

On success, return 0. On error, raise an exception and return -1.

Return -1 if value is NULL. It must be called with an exception raised in this case.

Example usage:

static int
add_spam(PyObject *module, int value)
{
    PyObject *obj = PyLong_FromLong(value);
    if (obj == NULL) {
        return -1;
    }
    int res = PyModule_AddObjectRef(module, "spam", obj);
    Py_DECREF(obj);
    return res;
 }

The example can also be written without checking explicitly if obj is NULL:

static int
add_spam(PyObject *module, int value)
{
    PyObject *obj = PyLong_FromLong(value);
    int res = PyModule_AddObjectRef(module, "spam", obj);
    Py_XDECREF(obj);
    return res;
 }

Note that Py_XDECREF() should be used instead of Py_DECREF() in this case, since obj can be NULL.

The number of different name strings passed to this function should be kept small, usually by only using statically allocated strings as name. For names that aren’t known at compile time, prefer calling PyUnicode_FromString() and PyObject_SetAttr() directly. For more details, see PyUnicode_InternFromString(), which may be used internally to create a key object.

Added in version 3.10.

int PyModule_Add(PyObject *module, const char *name, PyObject *value)

Part of the Stable ABI since version 3.13.

Similar to PyModule_AddObjectRef(), but “steals” a reference to value. It can be called with a result of function that returns a new reference without bothering to check its result or even saving it to a variable.

Example usage:

if (PyModule_Add(module, "spam", PyBytes_FromString(value)) < 0) {
    goto error;
}

Added in version 3.13.

int PyModule_AddObject(PyObject *module, const char *name, PyObject *value)

Part of the Stable ABI.

Similar to PyModule_AddObjectRef(), but steals a reference to value on success (if it returns 0).

The new PyModule_Add() or PyModule_AddObjectRef() functions are recommended, since it is easy to introduce reference leaks by misusing the PyModule_AddObject() function.

참고

Unlike other functions that steal references, PyModule_AddObject() only releases the reference to value on success.

This means that its return value must be checked, and calling code must Py_XDECREF() value manually on error.

Example usage:

PyObject *obj = PyBytes_FromString(value);
if (PyModule_AddObject(module, "spam", obj) < 0) {
    // If 'obj' is not NULL and PyModule_AddObject() failed,
    // 'obj' strong reference must be deleted with Py_XDECREF().
    // If 'obj' is NULL, Py_XDECREF() does nothing.
    Py_XDECREF(obj);
    goto error;
}
// PyModule_AddObject() stole a reference to obj:
// Py_XDECREF(obj) is not needed here.

버전 3.13부터 폐지됨: PyModule_AddObject() is soft deprecated.

int PyModule_AddIntConstant(PyObject *module, const char *name, long value)

Part of the Stable ABI.

Add an integer constant to module as name. This convenience function can be used from the module’s initialization function. Return -1 with an exception set on error, 0 on success.

This is a convenience function that calls PyLong_FromLong() and PyModule_AddObjectRef(); see their documentation for details.

int PyModule_AddStringConstant(PyObject *module, const char *name, const char *value)

Part of the Stable ABI.

Add a string constant to module as name. This convenience function can be used from the module’s initialization function. The string value must be NULL-terminated. Return -1 with an exception set on error, 0 on success.

This is a convenience function that calls PyUnicode_InternFromString() and PyModule_AddObjectRef(); see their documentation for details.

PyModule_AddIntMacro(module, macro)

Add an int constant to module. The name and the value are taken from macro. For example PyModule_AddIntMacro(module, AF_INET) adds the int constant AF_INET with the value of AF_INET to module. Return -1 with an exception set on error, 0 on success.

PyModule_AddStringMacro(module, macro)

module에 문자열 상수를 추가합니다.

int PyModule_AddType(PyObject *module, PyTypeObject *type)

Part of the Stable ABI since version 3.10.

Add a type object to module. The type object is finalized by calling internally PyType_Ready(). The name of the type object is taken from the last component of tp_name after dot. Return -1 with an exception set on error, 0 on success.

Added in version 3.9.

int PyUnstable_Module_SetGIL(PyObject *module, void *gil)

This is Unstable API. It may change without warning in minor releases.

Indicate that module does or does not support running without the global interpreter lock (GIL), using one of the values from Py_mod_gil. It must be called during module’s initialization function. If this function is not called during module initialization, the import machinery assumes the module does not support running without the GIL. This function is only available in Python builds configured with --disable-gil. Return -1 with an exception set on error, 0 on success.

Added in version 3.13.

모듈 조회

단단계 초기화는 현재 인터프리터의 컨텍스트에서 조회할 수 있는 싱글톤 모듈을 만듭니다. 이는 나중에 모듈 정의에 대한 참조만으로 모듈 객체를 검색할 수 있도록 합니다.

이 함수들은 다단계 초기화를 사용하여 만들어진 모듈에서는 작동하지 않습니다. 단일 정의에서 그러한 모듈이 여러 개 만들어질 수 있기 때문입니다.

PyObject *PyState_FindModule(PyModuleDef *def)

Return value: Borrowed reference. Part of the Stable ABI.

현재 인터프리터에 대해 def에서 만들어진 모듈 객체를 반환합니다. 이 메서드를 사용하려면 먼저 모듈 객체가 PyState_AddModule()로 인터프리터 상태에 연결되어 있어야 합니다. 해당 모듈 객체를 찾을 수 없거나 인터프리터 상태에 아직 연결되지 않았으면, NULL을 반환합니다.

int PyState_AddModule(PyObject *module, PyModuleDef *def)

Part of the Stable ABI since version 3.3.

함수에 전달된 모듈 객체를 인터프리터 상태에 연결합니다. 이는 PyState_FindModule()을 통해 모듈 객체에 액세스 할 수 있도록 합니다.

단단계 초기화를 사용하여 만든 모듈에만 효과가 있습니다.

파이썬은 모듈을 임포트 한 후 자동으로 PyState_AddModule을 호출하므로, 모듈 초기화 코드에서 호출하는 것은 불필요합니다 (하지만 무해합니다). 모듈의 자체 초기화 코드가 추후 PyState_FindModule을 호출하는 경우에만 명시적인 호출이 필요합니다. 이 함수는 주로 대안 임포트 메커니즘을 구현하기 위한 것입니다 (직접 호출하거나, 필요한 상태 갱신에 대한 자세한 내용에 대해 해당 구현을 참조함으로써).

호출자는 GIL을 보유해야 합니다.

Return -1 with an exception set on error, 0 on success.

Added in version 3.3.

int PyState_RemoveModule(PyModuleDef *def)

Part of the Stable ABI since version 3.3.

Removes the module object created from def from the interpreter state. Return -1 with an exception set on error, 0 on success.

호출자는 GIL을 보유해야 합니다.

Added in version 3.3.

이터레이터 객체

Python provides two general-purpose iterator objects. The first, a sequence iterator, works with an arbitrary sequence supporting the __getitem__() method. The second works with a callable object and a sentinel value, calling the callable for each item in the sequence, and ending the iteration when the sentinel value is returned.

PyTypeObject PySeqIter_Type

Part of the Stable ABI.

PySeqIter_New()와 내장 시퀀스 형에 대한 iter() 내장 함수의 단일 인자 형식에 의해 반환된 이터레이터 객체에 대한 형 객체.

int PySeqIter_Check(PyObject *op)

op의 형이 PySeqIter_Type이면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

PyObject *PySeqIter_New(PyObject *seq)

Return value: New reference. Part of the Stable ABI.

일반 시퀀스 객체 seq와 함께 작동하는 이터레이터를 반환합니다. 시퀀스가 서브스크립션 연산에서 IndexError를 일으키면 이터레이션이 끝납니다.

PyTypeObject PyCallIter_Type

Part of the Stable ABI.

PyCallIter_New()와 iter() 내장 함수의 두 인자 형식에 의해 반환된 이터레이터 객체에 대한 형 객체.

int PyCallIter_Check(PyObject *op)

op의 형이 PyCallIter_Type이면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

PyObject *PyCallIter_New(PyObject *callable, PyObject *sentinel)

Return value: New reference. Part of the Stable ABI.

새로운 이터레이터를 돌려줍니다. 첫 번째 매개 변수 callable은 매개 변수 없이 호출할 수 있는 모든 파이썬 콜러블 객체일 수 있습니다; 각 호출은 이터레이션의 다음 항목을 반환해야 합니다. callable이 sentinel와 같은 값을 반환하면 이터레이션이 종료됩니다.

디스크립터 객체

“디스크립터”는 객체의 일부 어트리뷰트를 기술하는 객체입니다. 그것들은 형 객체의 딕셔너리에 있습니다.

PyTypeObject PyProperty_Type

Part of the Stable ABI.

내장 디스크립터 형들을 위한 형 객체.

PyObject *PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset)

Return value: New reference. Part of the Stable ABI.

PyObject *PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *meth)

Return value: New reference. Part of the Stable ABI.

PyObject *PyDescr_NewMethod(PyTypeObject *type, struct PyMethodDef *meth)

Return value: New reference. Part of the Stable ABI.

PyObject *PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *wrapper, void *wrapped)

Return value: New reference.

PyObject *PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)

Return value: New reference. Part of the Stable ABI.

int PyDescr_IsData(PyObject *descr)

Return non-zero if the descriptor objects descr describes a data attribute, or 0 if it describes a method. descr must be a descriptor object; there is no error checking.

PyObject *PyWrapper_New(PyObject*, PyObject*)

Return value: New reference. Part of the Stable ABI.

슬라이스 객체

PyTypeObject PySlice_Type

Part of the Stable ABI.

슬라이스 객체의 형 객체. 이것은 파이썬 계층의 slice와 같습니다.

int PySlice_Check(PyObject *ob)

ob가 슬라이스 객체면 참을 반환합니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PySlice_New(PyObject *start, PyObject *stop, PyObject *step)

Return value: New reference. Part of the Stable ABI.

Return a new slice object with the given values. The start, stop, and step parameters are used as the values of the slice object attributes of the same names. Any of the values may be NULL, in which case the None will be used for the corresponding attribute.

Return NULL with an exception set if the new object could not be allocated.

int PySlice_GetIndices(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)

Part of the Stable ABI.

길이가 length인 시퀀스를 가정하여, 슬라이스 객체 slice에서 start, stop 및 step 인덱스를 가져옵니다. length보다 큰 인덱스를 에러로 처리합니다.

Returns 0 on success and -1 on error with no exception set (unless one of the indices was not None and failed to be converted to an integer, in which case -1 is returned with an exception set).

이 기능을 사용하고 싶지는 않을 것입니다.

버전 3.2에서 변경: 전에는 slice 매개 변수의 매개 변수 형이 PySliceObject*였습니다.

int PySlice_GetIndicesEx(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)

Part of the Stable ABI.

PySlice_GetIndices()를 쓸만하게 대체합니다. 길이가 length인 시퀀스를 가정하여, 슬라이스 객체 slice에서 start, stop 및 step 인덱스를 가져오고, slicelength에 슬라이스의 길이를 저장합니다. 범위를 벗어난 인덱스는 일반 슬라이스의 처리와 일관된 방식으로 잘립니다.

Return 0 on success and -1 on error with an exception set.

참고

이 함수는 크기를 조정할 수 있는 시퀀스에는 안전하지 않은 것으로 간주합니다. 호출은 PySlice_Unpack()와 PySlice_AdjustIndices()의 조합으로 대체되어야 합니다. 즉

if (PySlice_GetIndicesEx(slice, length, &start, &stop, &step, &slicelength) < 0) {
    // return error
}

은 다음으로 대체됩니다

if (PySlice_Unpack(slice, &start, &stop, &step) < 0) {
    // return error
}
slicelength = PySlice_AdjustIndices(length, &start, &stop, step);

버전 3.2에서 변경: 전에는 slice 매개 변수의 매개 변수 형이 PySliceObject*였습니다.

버전 3.6.1에서 변경: Py_LIMITED_API가 설정되어 있지 않거나 0x03050400과 0x03060000 (포함하지 않음) 사이나 0x03060100 이상의 값으로 설정되었으면, PySlice_GetIndicesEx()는 PySlice_Unpack()과 PySlice_AdjustIndices()를 사용하는 매크로로 구현됩니다. 인자 start, stop 및 step는 여러 번 평가됩니다.

버전 3.6.1부터 폐지됨: Py_LIMITED_API가 0x03050400보다 작거나 0x03060000과 0x03060100 (포함하지 않음) 사이의 값으로 설정되었으면 PySlice_GetIndicesEx()는 폐지된 함수입니다.

int PySlice_Unpack(PyObject *slice, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)

Part of the Stable ABI since version 3.7.

슬라이스 객체의 start, stop 및 step 데이터 멤버를 C 정수로 추출합니다. PY_SSIZE_T_MAX보다 큰 값을 PY_SSIZE_T_MAX로 조용히 줄이고, PY_SSIZE_T_MIN보다 작은 start 와 stop 값을 PY_SSIZE_T_MIN로 조용히 높이고, -PY_SSIZE_T_MAX보다 작은 step 값을 -PY_SSIZE_T_MAX로 조용히 높입니다.

Return -1 with an exception set on error, 0 on success.

Added in version 3.6.1.

Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)

Part of the Stable ABI since version 3.7.

지정된 length 길이의 시퀀스를 가정하여 start/stop 슬라이스 인덱스를 조정합니다. 범위를 벗어난 인덱스는 일반 슬라이스의 처리와 일관된 방식으로 잘립니다.

슬라이스의 길이를 반환합니다. 항상 성공합니다. 파이썬 코드를 호출하지 않습니다.

Added in version 3.6.1.

Ellipsis 객체

PyObject *Py_Ellipsis

The Python Ellipsis object. This object has no methods. Like Py_None, it is an immortal singleton object.

버전 3.12에서 변경: Py_Ellipsis is immortal.

MemoryView 객체

memoryview 객체는 C 수준 버퍼 인터페이스를 다른 객체와 마찬가지로 전달될 수 있는 파이썬 객체로 노출합니다.

PyObject *PyMemoryView_FromObject(PyObject *obj)

Return value: New reference. Part of the Stable ABI.

버퍼 인터페이스를 제공하는 객체에서 memoryview 객체를 만듭니다. obj가 쓰기 가능한 버퍼 제공을 지원하면, memoryview 객체는 읽기/쓰기가 되고, 그렇지 않으면 읽기 전용이거나 제공자의 재량에 따라 읽기/쓰기가 될 수 있습니다.

PyBUF_READ

Flag to request a readonly buffer.

PyBUF_WRITE

Flag to request a writable buffer.

PyObject *PyMemoryView_FromMemory(char *mem, Py_ssize_t size, int flags)

Return value: New reference. Part of the Stable ABI since version 3.7.

mem를 하부 버퍼로 사용하여 memoryview 객체를 만듭니다. flags는 PyBUF_READ 나 PyBUF_WRITE 중 하나일 수 있습니다.

Added in version 3.3.

PyObject *PyMemoryView_FromBuffer(const Py_buffer *view)

Return value: New reference. Part of the Stable ABI since version 3.11.

주어진 버퍼 구조체 view를 감싸는 memoryview 객체를 만듭니다. 간단한 바이트 버퍼의 경우는, PyMemoryView_FromMemory()가 선호되는 함수입니다.

PyObject *PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)

Return value: New reference. Part of the Stable ABI.

버퍼 인터페이스를 정의하는 객체로부터 메모리의 연속 청크(‘C’ 나 ‘F’ortran order로)로 memoryview 객체를 만듭니다. 메모리가 연속적이면 memoryview 객체는 원래 메모리를 가리킵니다. 그렇지 않으면, 복사본이 만들어지고 memoryview는 새 바이트열 객체를 가리킵니다.

buffertype can be one of PyBUF_READ or PyBUF_WRITE.

int PyMemoryView_Check(PyObject *obj)

객체 obj가 memoryview 객체면 참을 반환합니다. 현재는 memoryview의 서브 클래스를 만들 수 없습니다. 이 함수는 항상 성공합니다.

Py_buffer *PyMemoryView_GET_BUFFER(PyObject *mview)

제공자 버퍼의 memoryview의 비공개 복사본의 포인터를 돌려줍니다. mview는 반드시 memoryview 인스턴스여야 합니다; 이 매크로는 형을 확인하지 않으므로 직접 검사해야 합니다, 그렇지 않으면 충돌 위험이 있습니다.

PyObject *PyMemoryView_GET_BASE(PyObject *mview)

memoryview가 기반으로 하는 제공자 객체에 대한 포인터나 memoryview가 PyMemoryView_FromMemory() 나 PyMemoryView_FromBuffer() 함수 중 하나로 만들어졌으면 NULL을 반환합니다. mview는 반드시 memoryview 인스턴스여야 합니다.

약한 참조 객체

파이썬은 약한 참조를 1급 객체로 지원합니다. 약한 참조를 직접 구현하는 두 가지 구체적인 객체 형이 있습니다. 첫 번째는 간단한 참조 객체이며, 두 번째는 가능한 한 원래 객체의 프락시 역할을 합니다.

int PyWeakref_Check(PyObject *ob)

Return non-zero if ob is either a reference or proxy object. This function always succeeds.

int PyWeakref_CheckRef(PyObject *ob)

Return non-zero if ob is a reference object. This function always succeeds.

int PyWeakref_CheckProxy(PyObject *ob)

Return non-zero if ob is a proxy object. This function always succeeds.

PyObject *PyWeakref_NewRef(PyObject *ob, PyObject *callback)

Return value: New reference. Part of the Stable ABI.

Return a weak reference object for the object ob. This will always return a new reference, but is not guaranteed to create a new object; an existing reference object may be returned. The second parameter, callback, can be a callable object that receives notification when ob is garbage collected; it should accept a single parameter, which will be the weak reference object itself. callback may also be None or NULL. If ob is not a weakly referenceable object, or if callback is not callable, None, or NULL, this will return NULL and raise TypeError.

PyObject *PyWeakref_NewProxy(PyObject *ob, PyObject *callback)

Return value: New reference. Part of the Stable ABI.

Return a weak reference proxy object for the object ob. This will always return a new reference, but is not guaranteed to create a new object; an existing proxy object may be returned. The second parameter, callback, can be a callable object that receives notification when ob is garbage collected; it should accept a single parameter, which will be the weak reference object itself. callback may also be None or NULL. If ob is not a weakly referenceable object, or if callback is not callable, None, or NULL, this will return NULL and raise TypeError.

int PyWeakref_GetRef(PyObject *ref, PyObject **pobj)

Part of the Stable ABI since version 3.13.

Get a strong reference to the referenced object from a weak reference, ref, into *pobj.

On success, set *pobj to a new strong reference to the referenced object and return 1.

If the reference is dead, set *pobj to NULL and return 0.

On error, raise an exception and return -1.

Added in version 3.13.

PyObject *PyWeakref_GetObject(PyObject *ref)

Return value: Borrowed reference. Part of the Stable ABI.

Return a borrowed reference to the referenced object from a weak reference, ref. If the referent is no longer live, returns Py_None.

참고

This function returns a borrowed reference to the referenced object. This means that you should always call Py_INCREF() on the object except when it cannot be destroyed before the last usage of the borrowed reference.

Deprecated since version 3.13, will be removed in version 3.15: Use PyWeakref_GetRef() instead.

PyObject *PyWeakref_GET_OBJECT(PyObject *ref)

Return value: Borrowed reference.

Similar to PyWeakref_GetObject(), but does no error checking.

Deprecated since version 3.13, will be removed in version 3.15: Use PyWeakref_GetRef() instead.

void PyObject_ClearWeakRefs(PyObject *object)

Part of the Stable ABI.

This function is called by the tp_dealloc handler to clear weak references.

This iterates through the weak references for object and calls callbacks for those references which have one. It returns when all callbacks have been attempted.

void PyUnstable_Object_ClearWeakRefsNoCallbacks(PyObject *object)

This is Unstable API. It may change without warning in minor releases.

Clears the weakrefs for object without calling the callbacks.

This function is called by the tp_dealloc handler for types with finalizers (i.e., __del__()). The handler for those objects first calls PyObject_ClearWeakRefs() to clear weakrefs and call their callbacks, then the finalizer, and finally this function to clear any weakrefs that may have been created by the finalizer.

In most circumstances, it’s more appropriate to use PyObject_ClearWeakRefs() to clear weakrefs instead of this function.

Added in version 3.13.

캡슐

이 객체 사용에 대한 자세한 정보는 확장 모듈을 위한 C API 제공하기를 참조하십시오.

Added in version 3.1.

type PyCapsule

This subtype of PyObject represents an opaque value, useful for C extension modules who need to pass an opaque value (as a void* pointer) through Python code to other C code. It is often used to make a C function pointer defined in one module available to other modules, so the regular import mechanism can be used to access C APIs defined in dynamically loaded modules.

type PyCapsule_Destructor

Part of the Stable ABI.

캡슐에 대한 파괴자(destructor) 콜백 형. 이렇게 정의됩니다:

typedef void (*PyCapsule_Destructor)(PyObject *);

PyCapsule_Destructor 콜백의 의미는 PyCapsule_New()를 참조하십시오.

int PyCapsule_CheckExact(PyObject *p)

인자가 PyCapsule이면 참을 돌려줍니다. 이 함수는 항상 성공합니다.

PyObject *PyCapsule_New(void *pointer, const char *name, PyCapsule_Destructor destructor)

Return value: New reference. Part of the Stable ABI.

pointer를 캡슐화하는 PyCapsule을 만듭니다. pointer 인자는 NULL이 아닐 수도 있습니다.

실패하면, 예외를 설정하고 NULL을 반환합니다.

name 문자열은 NULL 이나 유효한 C 문자열에 대한 포인터일 수 있습니다. NULL이 아니면, 이 문자열은 캡슐보다 오래 유지되어야 합니다. (destructor 내부에서 해제할 수는 있습니다.)

destructor 인자가 NULL이 아니면, 캡슐이 파괴될 때 캡슐을 인자로 호출됩니다.

이 캡슐을 모듈의 어트리뷰트로 저장하려면, name을 modulename.attributename로 지정해야 합니다. 이렇게 하면 다른 모듈이 PyCapsule_Import()를 사용하여 캡슐을 임포트 할 수 있습니다.

void *PyCapsule_GetPointer(PyObject *capsule, const char *name)

Part of the Stable ABI.

캡슐에 저장된 pointer를 가져옵니다. 실패하면, 예외를 설정하고 NULL을 반환합니다.

The name parameter must compare exactly to the name stored in the capsule. If the name stored in the capsule is NULL, the name passed in must also be NULL. Python uses the C function strcmp() to compare capsule names.

PyCapsule_Destructor PyCapsule_GetDestructor(PyObject *capsule)

Part of the Stable ABI.

캡슐에 저장된 현재 파괴자를 반환합니다. 실패하면, 예외를 설정하고 NULL을 반환합니다.

캡슐이 NULL 파괴자를 갖는 것은 합법적입니다. 이것은 NULL 반환 코드를 다소 모호하게 만듭니다; 명확히 하려면 PyCapsule_IsValid() 나 PyErr_Occurred()를 사용하십시오.

void *PyCapsule_GetContext(PyObject *capsule)

Part of the Stable ABI.

캡슐에 저장된 현재 컨텍스트를 반환합니다. 실패하면, 예외를 설정하고 NULL을 반환합니다.

캡슐이 NULL 컨텍스트를 갖는 것은 합법적입니다. 이것은 NULL 반환 코드를 다소 모호하게 만듭니다; 명확히 하려면 PyCapsule_IsValid() 나 PyErr_Occurred()를 사용하십시오.

const char *PyCapsule_GetName(PyObject *capsule)

Part of the Stable ABI.

캡슐에 저장된 현재 이름을 반환합니다. 실패하면, 예외를 설정하고 NULL을 반환합니다.

캡슐이 NULL 이름을 갖는 것은 합법적입니다. 이것은 NULL 반환 코드를 다소 모호하게 만듭니다; 명확히 하려면 PyCapsule_IsValid() 나 PyErr_Occurred()를 사용하십시오.

void *PyCapsule_Import(const char *name, int no_block)

Part of the Stable ABI.

Import a pointer to a C object from a capsule attribute in a module. The name parameter should specify the full name to the attribute, as in module.attribute. The name stored in the capsule must match this string exactly.

성공하면 캡슐의 내부 pointer를 반환합니다. 실패하면, 예외를 설정하고 NULL를 반환합니다.

버전 3.3에서 변경: no_block has no effect anymore.

int PyCapsule_IsValid(PyObject *capsule, const char *name)

Part of the Stable ABI.

capsule이 유효한 캡슐인지를 판단합니다. 유효한 캡슐은 NULL이 아니며, PyCapsule_CheckExact()를 통과하고, NULL이 아닌 포인터가 저장되며, 내부 이름이 name 매개 변수와 일치합니다. (캡슐 이름을 비교하는 방법에 대한 정보는 PyCapsule_GetPointer()를 참조하십시오.)

In other words, if PyCapsule_IsValid() returns a true value, calls to any of the accessors (any function starting with PyCapsule_Get) are guaranteed to succeed.

객체가 유효하고 전달된 이름과 일치하면 0이 아닌 값을 반환합니다. 그렇지 않으면 0을 반환합니다. 이 함수는 실패하지 않습니다.

int PyCapsule_SetContext(PyObject *capsule, void *context)

Part of the Stable ABI.

capsule 내부의 컨텍스트 포인터를 context로 설정합니다.

성공하면 0을 반환합니다. 실패하면 0이 아닌 값을 반환하고 예외를 설정합니다.

int PyCapsule_SetDestructor(PyObject *capsule, PyCapsule_Destructor destructor)

Part of the Stable ABI.

capsule 내부의 파괴자를 destructor로 설정합니다.

성공하면 0을 반환합니다. 실패하면 0이 아닌 값을 반환하고 예외를 설정합니다.

int PyCapsule_SetName(PyObject *capsule, const char *name)

Part of the Stable ABI.

capsule 내부의 이름을 name으로 설정합니다. NULL이 아니면, 이름은 캡슐보다 오래 유지되어야 합니다. 캡슐에 저장된 이전 name이 NULL이 아니면, 이를 해제하려고 시도하지 않습니다.

성공하면 0을 반환합니다. 실패하면 0이 아닌 값을 반환하고 예외를 설정합니다.

int PyCapsule_SetPointer(PyObject *capsule, void *pointer)

Part of the Stable ABI.

capsule 내부의 void 포인터를 pointer로 설정합니다. 포인터는 NULL이 아닐 수 있습니다.

성공하면 0을 반환합니다. 실패하면 0이 아닌 값을 반환하고 예외를 설정합니다.

Frame Objects

type PyFrameObject

Part of the Limited API (as an opaque struct).

The C structure of the objects used to describe frame objects.

There are no public members in this structure.

버전 3.11에서 변경: The members of this structure were removed from the public C API. Refer to the What’s New entry for details.

The PyEval_GetFrame() and PyThreadState_GetFrame() functions can be used to get a frame object.

See also Reflection.

PyTypeObject PyFrame_Type

The type of frame objects. It is the same object as types.FrameType in the Python layer.

버전 3.11에서 변경: Previously, this type was only available after including <frameobject.h>.

int PyFrame_Check(PyObject *obj)

Return non-zero if obj is a frame object.

버전 3.11에서 변경: Previously, this function was only available after including <frameobject.h>.

PyFrameObject *PyFrame_GetBack(PyFrameObject *frame)

Return value: New reference.

Get the frame next outer frame.

Return a strong reference, or NULL if frame has no outer frame.

Added in version 3.9.

PyObject *PyFrame_GetBuiltins(PyFrameObject *frame)

Return value: New reference.

Get the frame’s f_builtins attribute.

Return a strong reference. The result cannot be NULL.

Added in version 3.11.

PyCodeObject *PyFrame_GetCode(PyFrameObject *frame)

Return value: New reference. Part of the Stable ABI since version 3.10.

Get the frame code.

Return a strong reference.

The result (frame code) cannot be NULL.

Added in version 3.9.

PyObject *PyFrame_GetGenerator(PyFrameObject *frame)

Return value: New reference.

Get the generator, coroutine, or async generator that owns this frame, or NULL if this frame is not owned by a generator. Does not raise an exception, even if the return value is NULL.

Return a strong reference, or NULL.

Added in version 3.11.

PyObject *PyFrame_GetGlobals(PyFrameObject *frame)

Return value: New reference.

Get the frame’s f_globals attribute.

Return a strong reference. The result cannot be NULL.

Added in version 3.11.

int PyFrame_GetLasti(PyFrameObject *frame)

Get the frame’s f_lasti attribute.

Returns -1 if frame.f_lasti is None.

Added in version 3.11.

PyObject *PyFrame_GetVar(PyFrameObject *frame, PyObject *name)

Return value: New reference.

Get the variable name of frame.

Return a strong reference to the variable value on success.

Raise NameError and return NULL if the variable does not exist.

Raise an exception and return NULL on error.

name type must be a str.

Added in version 3.12.

PyObject *PyFrame_GetVarString(PyFrameObject *frame, const char *name)

Return value: New reference.

Similar to PyFrame_GetVar(), but the variable name is a C string encoded in UTF-8.

Added in version 3.12.

PyObject *PyFrame_GetLocals(PyFrameObject *frame)

Return value: New reference.

Get the frame’s f_locals attribute. If the frame refers to an optimized scope, this returns a write-through proxy object that allows modifying the locals. In all other cases (classes, modules, exec(), eval()) it returns the mapping representing the frame locals directly (as described for locals()).

Return a strong reference.

Added in version 3.11.

버전 3.13에서 변경: As part of PEP 667 [https://peps.python.org/pep-0667/], return a proxy object for optimized scopes.

int PyFrame_GetLineNumber(PyFrameObject *frame)

Part of the Stable ABI since version 3.10.

Return the line number that frame is currently executing.

Internal Frames

Unless using PEP 523 [https://peps.python.org/pep-0523/], you will not need this.

struct _PyInterpreterFrame

The interpreter’s internal frame representation.

Added in version 3.11.

PyObject *PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame);

This is Unstable API. It may change without warning in minor releases.

Return a strong reference to the code object for the frame.

Added in version 3.12.

int PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame);

This is Unstable API. It may change without warning in minor releases.

Return the byte offset into the last executed instruction.

Added in version 3.12.

int PyUnstable_InterpreterFrame_GetLine(struct _PyInterpreterFrame *frame);

This is Unstable API. It may change without warning in minor releases.

Return the currently executing line number, or -1 if there is no line number.

Added in version 3.12.

제너레이터 객체

제너레이터 객체는 파이썬이 제너레이터 이터레이터를 구현하기 위해 사용하는 객체입니다. 일반적으로 PyGen_New() 또는 PyGen_NewWithQualName()를 명시적으로 호출하는 것이 아니라, 값을 일드(yield)하는 함수를 이터레이트하여 만들어집니다.

type PyGenObject

제너레이터 객체에 사용되는 C 구조체.

PyTypeObject PyGen_Type

제너레이터 객체에 해당하는 형 객체

int PyGen_Check(PyObject *ob)

ob가 제너레이터 객체면 참을 돌려줍니다; ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyGen_CheckExact(PyObject *ob)

ob의 형이 PyGen_Type이면 참을 돌려줍니다; ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

PyObject *PyGen_New(PyFrameObject *frame)

Return value: New reference.

frame 객체에 기반한 새 제너레이터 객체를 만들어 반환합니다. 이 함수는 frame에 대한 참조를 훔칩니다. 인자는 NULL이 아니어야 합니다.

PyObject *PyGen_NewWithQualName(PyFrameObject *frame, PyObject *name, PyObject *qualname)

Return value: New reference.

frame 객체에 기반한 새 제너레이터 객체를 만들어 반환하는데, __name__ 과 __qualname__를 name 및 qualname로 설정합니다. 이 함수는 frame에 대한 참조를 훔칩니다. frame 인자는 NULL이 아니어야 합니다.

코루틴 객체

Added in version 3.5.

코루틴 객체는 async 키워드로 선언된 함수가 반환하는 것입니다.

type PyCoroObject

코루틴 객체에 사용되는 C 구조체.

PyTypeObject PyCoro_Type

코루틴 객체에 해당하는 형 객체.

int PyCoro_CheckExact(PyObject *ob)

ob의 형이 PyCoro_Type이면 참을 반환합니다. ob는 NULL일 수 없습니다. 이 함수는 항상 성공합니다.

PyObject *PyCoro_New(PyFrameObject *frame, PyObject *name, PyObject *qualname)

Return value: New reference.

frame 객체를 기반으로 새 코루틴 객체를 만들어서 반환합니다. __name__ 과 __qualname__은 name 과 qualname로 설정합니다. 이 함수는 frame에 대한 참조를 훔칩니다. frame 인자는 NULL일 수 없습니다.

컨텍스트 변수 객체

Added in version 3.7.

버전 3.7.1에서 변경:

참고

파이썬 3.7.1에서 모든 컨텍스트 변수 C API의 서명이 PyContext, PyContextVar 및 PyContextToken 대신 PyObject 포인터를 사용하도록 변경되었습니다, 예를 들어:

// in 3.7.0:
PyContext *PyContext_New(void);

// in 3.7.1+:
PyObject *PyContext_New(void);

자세한 내용은 bpo-34762 [https://bugs.python.org/issue?@action=redirect&bpo=34762]를 참조하십시오.

이 절에서는 contextvars 모듈을 위한 공용 C API에 대해 자세히 설명합니다.

type PyContext

contextvars.Context 객체를 나타내는 데 사용되는 C 구조체.

type PyContextVar

contextvars.ContextVar 객체를 나타내는 데 사용되는 C 구조체.

type PyContextToken

contextvars.Token 객체를 나타내는 데 사용되는 C 구조체.

PyTypeObject PyContext_Type

context 형을 나타내는 형 객체.

PyTypeObject PyContextVar_Type

컨텍스트 변수 형을 나타내는 형 객체.

PyTypeObject PyContextToken_Type

컨텍스트 변수 토큰 형을 나타내는 형 객체.

형 검사 매크로:

int PyContext_CheckExact(PyObject *o)

o가 PyContext_Type 형이면 참을 돌려줍니다. o는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyContextVar_CheckExact(PyObject *o)

o가 PyContextVar_Type 형이면 참을 돌려줍니다. o는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyContextToken_CheckExact(PyObject *o)

o가 PyContextToken_Type 형이면 참을 돌려줍니다. o는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

컨텍스트 객체 관리 함수:

PyObject *PyContext_New(void)

Return value: New reference.

새로운 빈 컨텍스트 객체를 만듭니다. 에러가 발생하면 NULL를 반환합니다.

PyObject *PyContext_Copy(PyObject *ctx)

Return value: New reference.

전달된 ctx 컨텍스트 객체의 얕은 복사본을 만듭니다. 에러가 발생하면 NULL을 반환합니다.

PyObject *PyContext_CopyCurrent(void)

Return value: New reference.

현재 스레드 컨텍스트의 얕은 복사본을 만듭니다. 에러가 발생하면 NULL을 반환합니다.

int PyContext_Enter(PyObject *ctx)

현재 스레드의 현재 컨텍스트로 ctx를 설정합니다. 성공 시 0을 반환하고, 에러 시 -1을 반환합니다.

int PyContext_Exit(PyObject *ctx)

ctx 컨텍스트를 비활성화하고 이전 컨텍스트를 현재 스레드의 현재 컨텍스트로 복원합니다. 성공 시 0을 반환하고, 에러 시 -1을 반환합니다.

int PyContext_AddWatcher(PyContext_WatchCallback callback)

Register callback as a context object watcher for the current interpreter. Return an ID which may be passed to PyContext_ClearWatcher(). In case of error (e.g. no more watcher IDs available), return -1 and set an exception.

Added in version 3.14.

int PyContext_ClearWatcher(int watcher_id)

Clear watcher identified by watcher_id previously returned from PyContext_AddWatcher() for the current interpreter. Return 0 on success, or -1 and set an exception on error (e.g. if the given watcher_id was never registered.)

Added in version 3.14.

type PyContextEvent

Enumeration of possible context object watcher events:

Py_CONTEXT_SWITCHED: The current context has switched to a different context. The object passed to the watch callback is the now-current contextvars.Context object, or None if no context is current.

Added in version 3.14.

typedef int (*PyContext_WatchCallback)(PyContextEvent event, PyObject *obj)

Context object watcher callback function. The object passed to the callback is event-specific; see PyContextEvent for details.

If the callback returns with an exception set, it must return -1; this exception will be printed as an unraisable exception using PyErr_FormatUnraisable(). Otherwise it should return 0.

There may already be a pending exception set on entry to the callback. In this case, the callback should return 0 with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.

Added in version 3.14.

컨텍스트 변수 함수:

PyObject *PyContextVar_New(const char *name, PyObject *def)

Return value: New reference.

Create a new ContextVar object. The name parameter is used for introspection and debug purposes. The def parameter specifies a default value for the context variable, or NULL for no default. If an error has occurred, this function returns NULL.

int PyContextVar_Get(PyObject *var, PyObject *default_value, PyObject **value)

컨텍스트 변수의 값을 가져옵니다. 조회하는 동안 에러가 발생하면 -1을 반환하고, 값이 있는지와 상관없이 에러가 발생하지 않으면 0을 반환합니다.

컨텍스트 변수가 발견되면, value는 그것을 가리키는 포인터가 됩니다. 컨텍스트 변수가 발견되지 않으면, value는 다음을 가리 킵니다:

default_value, NULL이 아니면;

var의 기본값, NULL이 아니면;

NULL

Except for NULL, the function returns a new reference.

PyObject *PyContextVar_Set(PyObject *var, PyObject *value)

Return value: New reference.

Set the value of var to value in the current context. Returns a new token object for this change, or NULL if an error has occurred.

int PyContextVar_Reset(PyObject *var, PyObject *token)

var 컨텍스트 변수의 상태를 token을 반환한 PyContextVar_Set() 호출 전의 상태로 재설정합니다. 이 함수는 성공 시 0을 반환하고, 에러 시 -1을 반환합니다.

DateTime 객체

Various date and time objects are supplied by the datetime module. Before using any of these functions, the header file datetime.h must be included in your source (note that this is not included by Python.h), and the macro PyDateTime_IMPORT must be invoked, usually as part of the module initialisation function. The macro puts a pointer to a C structure into a static variable, PyDateTimeAPI, that is used by the following macros.

type PyDateTime_Date

This subtype of PyObject represents a Python date object.

type PyDateTime_DateTime

This subtype of PyObject represents a Python datetime object.

type PyDateTime_Time

This subtype of PyObject represents a Python time object.

type PyDateTime_Delta

This subtype of PyObject represents the difference between two datetime values.

PyTypeObject PyDateTime_DateType

This instance of PyTypeObject represents the Python date type; it is the same object as datetime.date in the Python layer.

PyTypeObject PyDateTime_DateTimeType

This instance of PyTypeObject represents the Python datetime type; it is the same object as datetime.datetime in the Python layer.

PyTypeObject PyDateTime_TimeType

This instance of PyTypeObject represents the Python time type; it is the same object as datetime.time in the Python layer.

PyTypeObject PyDateTime_DeltaType

This instance of PyTypeObject represents Python type for the difference between two datetime values; it is the same object as datetime.timedelta in the Python layer.

PyTypeObject PyDateTime_TZInfoType

This instance of PyTypeObject represents the Python time zone info type; it is the same object as datetime.tzinfo in the Python layer.

UTC 싱글톤에 액세스하기 위한 매크로:

PyObject *PyDateTime_TimeZone_UTC

UTC를 나타내는 시간대 싱글톤을 반환합니다, datetime.timezone.utc와 같은 객체입니다.

Added in version 3.7.

형 검사 매크로:

int PyDate_Check(PyObject *ob)

Return true if ob is of type PyDateTime_DateType or a subtype of PyDateTime_DateType. ob must not be NULL. This function always succeeds.

int PyDate_CheckExact(PyObject *ob)

ob가 PyDateTime_DateType 형이면 참을 돌려줍니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyDateTime_Check(PyObject *ob)

Return true if ob is of type PyDateTime_DateTimeType or a subtype of PyDateTime_DateTimeType. ob must not be NULL. This function always succeeds.

int PyDateTime_CheckExact(PyObject *ob)

ob가 PyDateTime_DateTimeType 형이면 참을 돌려줍니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyTime_Check(PyObject *ob)

Return true if ob is of type PyDateTime_TimeType or a subtype of PyDateTime_TimeType. ob must not be NULL. This function always succeeds.

int PyTime_CheckExact(PyObject *ob)

ob가 PyDateTime_TimeType 형이면 참을 돌려줍니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyDelta_Check(PyObject *ob)

Return true if ob is of type PyDateTime_DeltaType or a subtype of PyDateTime_DeltaType. ob must not be NULL. This function always succeeds.

int PyDelta_CheckExact(PyObject *ob)

ob가 PyDateTime_DeltaType 형이면 참을 돌려줍니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

int PyTZInfo_Check(PyObject *ob)

Return true if ob is of type PyDateTime_TZInfoType or a subtype of PyDateTime_TZInfoType. ob must not be NULL. This function always succeeds.

int PyTZInfo_CheckExact(PyObject *ob)

ob가 PyDateTime_TZInfoType 형이면 참을 돌려줍니다. ob는 NULL이 아니어야 합니다. 이 함수는 항상 성공합니다.

객체를 만드는 매크로:

PyObject *PyDate_FromDate(int year, int month, int day)

Return value: New reference.

지정된 년, 월, 일의 datetime.date 객체를 반환합니다.

PyObject *PyDateTime_FromDateAndTime(int year, int month, int day, int hour, int minute, int second, int usecond)

Return value: New reference.

지정된 년, 월, 일, 시, 분, 초 및 마이크로초의 datetime.datetime 객체를 반환합니다.

PyObject *PyDateTime_FromDateAndTimeAndFold(int year, int month, int day, int hour, int minute, int second, int usecond, int fold)

Return value: New reference.

지정된 년, 월, 일, 시, 분, 초, 마이크로초 및 fold의 datetime.datetime 객체를 반환합니다.

Added in version 3.6.

PyObject *PyTime_FromTime(int hour, int minute, int second, int usecond)

Return value: New reference.

지정된 시, 분, 초 및 마이크로초의 datetime.time 객체를 반환합니다.

PyObject *PyTime_FromTimeAndFold(int hour, int minute, int second, int usecond, int fold)

Return value: New reference.

지정된 시, 분, 초, 마이크로초 및 fold의 datetime.time 객체를 반환합니다.

Added in version 3.6.

PyObject *PyDelta_FromDSU(int days, int seconds, int useconds)

Return value: New reference.

지정된 일, 초 및 마이크로초 수를 나타내는 datetime.timedelta 객체를 반환합니다. 결과 마이크로초와 초가 datetime.timedelta 객체에 관해 설명된 범위에 있도록 정규화가 수행됩니다.

PyObject *PyTimeZone_FromOffset(PyObject *offset)

Return value: New reference.

offset 인자로 나타내지는 이름이 없는 고정 오프셋의 datetime.timezone 객체를 돌려줍니다.

Added in version 3.7.

PyObject *PyTimeZone_FromOffsetAndName(PyObject *offset, PyObject *name)

Return value: New reference.

offset 인자와 tzname name으로 나타내지는 고정 오프셋의 datetime.timezone 객체를 돌려줍니다.

Added in version 3.7.

Macros to extract fields from date objects. The argument must be an instance of PyDateTime_Date, including subclasses (such as PyDateTime_DateTime). The argument must not be NULL, and the type is not checked:

int PyDateTime_GET_YEAR(PyDateTime_Date *o)

양의 int로, 년을 반환합니다.

int PyDateTime_GET_MONTH(PyDateTime_Date *o)

1에서 12까지의 int로, 월을 반환합니다.

int PyDateTime_GET_DAY(PyDateTime_Date *o)

1에서 31까지의 int로, 일을 반환합니다.

Macros to extract fields from datetime objects. The argument must be an instance of PyDateTime_DateTime, including subclasses. The argument must not be NULL, and the type is not checked:

int PyDateTime_DATE_GET_HOUR(PyDateTime_DateTime *o)

0부터 23까지의 int로, 시를 반환합니다.

int PyDateTime_DATE_GET_MINUTE(PyDateTime_DateTime *o)

0부터 59까지의 int로, 분을 반환합니다.

int PyDateTime_DATE_GET_SECOND(PyDateTime_DateTime *o)

0부터 59까지의 int로, 초를 반환합니다.

int PyDateTime_DATE_GET_MICROSECOND(PyDateTime_DateTime *o)

0부터 999999까지의 int로, 마이크로초를 반환합니다.

int PyDateTime_DATE_GET_FOLD(PyDateTime_DateTime *o)

Return the fold, as an int from 0 through 1.

Added in version 3.6.

PyObject *PyDateTime_DATE_GET_TZINFO(PyDateTime_DateTime *o)

Return the tzinfo (which may be None).

Added in version 3.10.

Macros to extract fields from time objects. The argument must be an instance of PyDateTime_Time, including subclasses. The argument must not be NULL, and the type is not checked:

int PyDateTime_TIME_GET_HOUR(PyDateTime_Time *o)

0부터 23까지의 int로, 시를 반환합니다.

int PyDateTime_TIME_GET_MINUTE(PyDateTime_Time *o)

0부터 59까지의 int로, 분을 반환합니다.

int PyDateTime_TIME_GET_SECOND(PyDateTime_Time *o)

0부터 59까지의 int로, 초를 반환합니다.

int PyDateTime_TIME_GET_MICROSECOND(PyDateTime_Time *o)

0부터 999999까지의 int로, 마이크로초를 반환합니다.

int PyDateTime_TIME_GET_FOLD(PyDateTime_Time *o)

Return the fold, as an int from 0 through 1.

Added in version 3.6.

PyObject *PyDateTime_TIME_GET_TZINFO(PyDateTime_Time *o)

Return the tzinfo (which may be None).

Added in version 3.10.

Macros to extract fields from time delta objects. The argument must be an instance of PyDateTime_Delta, including subclasses. The argument must not be NULL, and the type is not checked:

int PyDateTime_DELTA_GET_DAYS(PyDateTime_Delta *o)

-999999999에서 999999999까지의 int로, 일 수를 반환합니다.

Added in version 3.3.

int PyDateTime_DELTA_GET_SECONDS(PyDateTime_Delta *o)

0부터 86399까지의 int로, 초 수를 반환합니다.

Added in version 3.3.

int PyDateTime_DELTA_GET_MICROSECONDS(PyDateTime_Delta *o)

0에서 999999까지의 int로, 마이크로초 수를 반환합니다.

Added in version 3.3.

DB API를 구현하는 모듈의 편의를 위한 매크로:

PyObject *PyDateTime_FromTimestamp(PyObject *args)

Return value: New reference.

Create and return a new datetime.datetime object given an argument tuple suitable for passing to datetime.datetime.fromtimestamp().

PyObject *PyDate_FromTimestamp(PyObject *args)

Return value: New reference.

Create and return a new datetime.date object given an argument tuple suitable for passing to datetime.date.fromtimestamp().

Objects for Type Hinting

Various built-in types for type hinting are provided. Currently, two types exist – GenericAlias and Union. Only GenericAlias is exposed to C.

PyObject *Py_GenericAlias(PyObject *origin, PyObject *args)

Part of the Stable ABI since version 3.9.

Create a GenericAlias object. Equivalent to calling the Python class types.GenericAlias. The origin and args arguments set the GenericAlias‘s __origin__ and __args__ attributes respectively. origin should be a PyTypeObject*, and args can be a PyTupleObject* or any PyObject*. If args passed is not a tuple, a 1-tuple is automatically constructed and __args__ is set to (args,). Minimal checking is done for the arguments, so the function will succeed even if origin is not a type. The GenericAlias‘s __parameters__ attribute is constructed lazily from __args__. On failure, an exception is raised and NULL is returned.

Here’s an example of how to make an extension type generic:

...
static PyMethodDef my_obj_methods[] = {
    // Other methods.
    ...
    {"__class_getitem__", Py_GenericAlias, METH_O|METH_CLASS, "See PEP 585"}
    ...
}

더 보기

The data model method __class_getitem__().

Added in version 3.9.

PyTypeObject Py_GenericAliasType

Part of the Stable ABI since version 3.9.

The C type of the object returned by Py_GenericAlias(). Equivalent to types.GenericAlias in Python.

Added in version 3.9.

초기화, 파이널리제이션 및 스레드

See Python Initialization Configuration for details on how to configure the interpreter prior to initialization.

파이썬 초기화 전

파이썬을 내장한 응용 프로그램에서는, 다른 파이썬/C API 함수를 사용하기 전에 Py_Initialize() 함수를 호출해야 합니다; 몇 가지 함수와 전역 구성 변수는 예외입니다.

파이썬이 초기화되기 전에 다음 함수를 안전하게 호출할 수 있습니다:

Functions that initialize the interpreter:

Py_Initialize()

Py_InitializeEx()

Py_InitializeFromConfig()

Py_BytesMain()

Py_Main()

the runtime pre-initialization functions covered in 파이썬 초기화 구성

구성 함수:

PyImport_AppendInittab()

PyImport_ExtendInittab()

PyInitFrozenExtensions()

PyMem_SetAllocator()

PyMem_SetupDebugHooks()

PyObject_SetArenaAllocator()

Py_SetProgramName()

Py_SetPythonHome()

PySys_ResetWarnOptions()

the configuration functions covered in 파이썬 초기화 구성

정보 함수:

Py_IsInitialized()

PyMem_GetAllocator()

PyObject_GetArenaAllocator()

Py_GetBuildInfo()

Py_GetCompiler()

Py_GetCopyright()

Py_GetPlatform()

Py_GetVersion()

Py_IsInitialized()

유틸리티:

Py_DecodeLocale()

the status reporting and utility functions covered in 파이썬 초기화 구성

메모리 할당자:

PyMem_RawMalloc()

PyMem_RawRealloc()

PyMem_RawCalloc()

PyMem_RawFree()

Synchronization:

PyMutex_Lock()

PyMutex_Unlock()

참고

Despite their apparent similarity to some of the functions listed above, the following functions should not be called before the interpreter has been initialized: Py_EncodeLocale(), Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix(), Py_GetProgramFullPath(), Py_GetPythonHome(), Py_GetProgramName(), PyEval_InitThreads(), and Py_RunMain().

전역 구성 변수

파이썬에는 다양한 기능과 옵션을 제어하기 위한 전역 구성 변수가 있습니다. 기본적으로, 이러한 플래그는 명령 줄 옵션에 의해 제어됩니다.

옵션에 의해 플래그가 설정되면, 플래그 값은 옵션이 설정된 횟수입니다. 예를 들어, -b는 Py_BytesWarningFlag 를 1로 설정하고 -bb는 Py_BytesWarningFlag 를 2로 설정합니다.

int Py_BytesWarningFlag

This API is kept for backward compatibility: setting PyConfig.bytes_warning should be used instead, see Python Initialization Configuration.

bytes나 bytearray와 str을, 또는 bytes를 int와 비교할 때 경고를 발행합니다. 2보다 크거나 같으면 에러를 발행합니다.

-b 옵션으로 설정합니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_DebugFlag

This API is kept for backward compatibility: setting PyConfig.parser_debug should be used instead, see Python Initialization Configuration.

구문 분석기 디버깅 출력을 켭니다 (전문가 전용, 컴파일 옵션에 의존합니다).

-d 옵션과 PYTHONDEBUG 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_DontWriteBytecodeFlag

This API is kept for backward compatibility: setting PyConfig.write_bytecode should be used instead, see Python Initialization Configuration.

0이 아닌 값으로 설정하면, 파이썬은 소스 모듈을 임포트 할 때 .pyc 파일을 쓰려고 하지 않습니다.

-B 옵션과 PYTHONDONTWRITEBYTECODE 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_FrozenFlag

This API is kept for backward compatibility: setting PyConfig.pathconfig_warnings should be used instead, see Python Initialization Configuration.

Py_GetPath()에서 모듈 검색 경로를 계산할 때 에러 메시지를 표시하지 않습니다.

Private flag used by _freeze_module and frozenmain programs.

Deprecated since version 3.12, removed in version 3.14.

int Py_HashRandomizationFlag

This API is kept for backward compatibility: setting PyConfig.hash_seed and PyConfig.use_hash_seed should be used instead, see Python Initialization Configuration.

PYTHONHASHSEED 환경 변수가 비어 있지 않은 문자열로 설정되면 1로 설정합니다.

플래그가 0이 아니면, PYTHONHASHSEED 환경 변수를 읽어 비밀 해시 시드를 초기화합니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_IgnoreEnvironmentFlag

This API is kept for backward compatibility: setting PyConfig.use_environment should be used instead, see Python Initialization Configuration.

Ignore all PYTHON* environment variables, e.g. PYTHONPATH and PYTHONHOME, that might be set.

-E와 -I 옵션으로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_InspectFlag

This API is kept for backward compatibility: setting PyConfig.inspect should be used instead, see Python Initialization Configuration.

스크립트가 첫 번째 인자로 전달되거나 -c 옵션을 사용할 때, sys.stdin가 터미널로 보이지 않더라도 스크립트나 명령을 실행한 후 대화 형 모드로 들어갑니다.

-i 옵션과 PYTHONINSPECT 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_InteractiveFlag

This API is kept for backward compatibility: setting PyConfig.interactive should be used instead, see Python Initialization Configuration.

-i 옵션으로 설정됩니다.

버전 3.12부터 폐지됨.

int Py_IsolatedFlag

This API is kept for backward compatibility: setting PyConfig.isolated should be used instead, see Python Initialization Configuration.

격리 모드로 파이썬을 실행합니다. 격리 모드에서 sys.path는 스크립트의 디렉터리도 사용자의 site-packages 디렉터리도 포함하지 않습니다.

-I 옵션으로 설정됩니다.

Added in version 3.4.

Deprecated since version 3.12, removed in version 3.14.

int Py_LegacyWindowsFSEncodingFlag

This API is kept for backward compatibility: setting PyPreConfig.legacy_windows_fs_encoding should be used instead, see Python Initialization Configuration.

If the flag is non-zero, use the mbcs encoding with replace error handler, instead of the UTF-8 encoding with surrogatepass error handler, for the filesystem encoding and error handler.

PYTHONLEGACYWINDOWSFSENCODING 환경 변수가 비어 있지 않은 문자열로 설정되면 1로 설정합니다.

자세한 내용은 PEP 529 [https://peps.python.org/pep-0529/]를 참조하십시오.

Availability: Windows.

Deprecated since version 3.12, removed in version 3.14.

int Py_LegacyWindowsStdioFlag

This API is kept for backward compatibility: setting PyConfig.legacy_windows_stdio should be used instead, see Python Initialization Configuration.

If the flag is non-zero, use io.FileIO instead of io._WindowsConsoleIO for sys standard streams.

PYTHONLEGACYWINDOWSSTDIO 환경 변수가 비어 있지 않은 문자열로 설정되면 1로 설정합니다.

자세한 내용은 PEP 528 [https://peps.python.org/pep-0528/]을 참조하십시오.

Availability: Windows.

Deprecated since version 3.12, removed in version 3.14.

int Py_NoSiteFlag

This API is kept for backward compatibility: setting PyConfig.site_import should be used instead, see Python Initialization Configuration.

모듈 site 임포트와 이에 수반되는 sys.path의 사이트 종속적인 조작을 비활성화합니다. 또한 나중에 site를 명시적으로 임포트 할 때도 이러한 조작을 비활성화합니다 (트리거 하려면 site.main()을 호출하십시오).

-S 옵션으로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_NoUserSiteDirectory

This API is kept for backward compatibility: setting PyConfig.user_site_directory should be used instead, see Python Initialization Configuration.

사용자 site-packages 디렉터리를 sys.path에 추가하지 않습니다.

-s와 -I 옵션, 그리고 PYTHONNOUSERSITE 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_OptimizeFlag

This API is kept for backward compatibility: setting PyConfig.optimization_level should be used instead, see Python Initialization Configuration.

-O 옵션과 PYTHONOPTIMIZE 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_QuietFlag

This API is kept for backward compatibility: setting PyConfig.quiet should be used instead, see Python Initialization Configuration.

대화형 모드에서도 저작권과 버전 메시지를 표시하지 않습니다.

-q 옵션으로 설정됩니다.

Added in version 3.2.

Deprecated since version 3.12, removed in version 3.14.

int Py_UnbufferedStdioFlag

This API is kept for backward compatibility: setting PyConfig.buffered_stdio should be used instead, see Python Initialization Configuration.

stdout과 stderr 스트림을 버퍼링 해제하도록 강제합니다.

-u 옵션과 PYTHONUNBUFFERED 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

int Py_VerboseFlag

This API is kept for backward compatibility: setting PyConfig.verbose should be used instead, see Python Initialization Configuration.

모듈이 초기화될 때마다, 로드된 위치(파일명이나 내장 모듈)를 표시하는 메시지를 인쇄합니다. 2보다 크거나 같으면, 모듈을 검색할 때 검사되는 각 파일에 대한 메시지를 인쇄합니다. 또한 종료 시 모듈 정리에 대한 정보를 제공합니다.

-v 옵션과 PYTHONVERBOSE 환경 변수로 설정됩니다.

Deprecated since version 3.12, removed in version 3.14.

인터프리터 초기화와 파이널리제이션

void Py_Initialize()

Part of the Stable ABI.

파이썬 인터프리터를 초기화합니다. 파이썬을 내장하는 응용 프로그램에서는, 다른 파이썬/C API 함수를 사용하기 전에 호출해야 합니다; 몇 가지 예외는 파이썬 초기화 전을 참조하십시오.

This initializes the table of loaded modules (sys.modules), and creates the fundamental modules builtins, __main__ and sys. It also initializes the module search path (sys.path). It does not set sys.argv; use the Python Initialization Configuration API for that. This is a no-op when called for a second time (without calling Py_FinalizeEx() first). There is no return value; it is a fatal error if the initialization fails.

Use Py_InitializeFromConfig() to customize the Python Initialization Configuration.

참고

윈도우에서, 콘솔 모드를 O_TEXT에서 O_BINARY로 변경합니다, C 런타임을 사용하는 콘솔의 비 파이썬 사용에도 영향을 미칩니다.

void Py_InitializeEx(int initsigs)

Part of the Stable ABI.

This function works like Py_Initialize() if initsigs is 1. If initsigs is 0, it skips initialization registration of signal handlers, which may be useful when CPython is embedded as part of a larger application.

Use Py_InitializeFromConfig() to customize the Python Initialization Configuration.

PyStatus Py_InitializeFromConfig(const PyConfig *config)

Initialize Python from config configuration, as described in PyConfig를 사용한 초기화.

See the 파이썬 초기화 구성 section for details on pre-initializing the interpreter, populating the runtime configuration structure, and querying the returned status structure.

int Py_IsInitialized()

Part of the Stable ABI.

파이썬 인터프리터가 초기화되었으면 참(0이 아님)을 반환하고, 그렇지 않으면 거짓(0)을 반환합니다. Py_FinalizeEx() 가 호출된 후, Py_Initialize()가 다시 호출될 때까지 거짓을 반환합니다.

int Py_IsFinalizing()

Part of the Stable ABI since version 3.13.

Return true (non-zero) if the main Python interpreter is shutting down. Return false (zero) otherwise.

Added in version 3.13.

int Py_FinalizeEx()

Part of the Stable ABI since version 3.6.

Undo all initializations made by Py_Initialize() and subsequent use of Python/C API functions, and destroy all sub-interpreters (see Py_NewInterpreter() below) that were created and not yet destroyed since the last call to Py_Initialize(). This is a no-op when called for a second time (without calling Py_Initialize() again first).

Since this is the reverse of Py_Initialize(), it should be called in the same thread with the same interpreter active. That means the main thread and the main interpreter. This should never be called while Py_RunMain() is running.

Normally the return value is 0. If there were errors during finalization (flushing buffered data), -1 is returned.

Note that Python will do a best effort at freeing all memory allocated by the Python interpreter. Therefore, any C-Extension should make sure to correctly clean up all of the preveiously allocated PyObjects before using them in subsequent calls to Py_Initialize(). Otherwise it could introduce vulnerabilities and incorrect behavior.

이 함수는 여러 가지 이유로 제공됩니다. 내장 응용 프로그램이 응용 프로그램 자체를 다시 시작하지 않고 파이썬을 다시 시작하고 싶을 수 있습니다. 동적으로 로드할 수 있는 라이브러리(또는 DLL)에서 파이썬 인터프리터를 로드한 응용 프로그램은 DLL을 언로드 하기 전에 파이썬이 할당한 모든 메모리를 해제하고 싶을 수 있습니다. 응용 프로그램에서 메모리 누수를 찾는 동안 개발자는 응용 프로그램을 종료하기 전에 파이썬에서 할당한 모든 메모리를 해제하고 싶을 것입니다.

Bugs and caveats: The destruction of modules and objects in modules is done in random order; this may cause destructors (__del__() methods) to fail when they depend on other objects (even functions) or modules. Dynamically loaded extension modules loaded by Python are not unloaded. Small amounts of memory allocated by the Python interpreter may not be freed (if you find a leak, please report it). Memory tied up in circular references between objects is not freed. Interned strings will all be deallocated regardless of their reference count. Some memory allocated by extension modules may not be freed. Some extensions may not work properly if their initialization routine is called more than once; this can happen if an application calls Py_Initialize() and Py_FinalizeEx() more than once. Py_FinalizeEx() must not be called recursively from within itself. Therefore, it must not be called by any code that may be run as part of the interpreter shutdown process, such as atexit handlers, object finalizers, or any code that may be run while flushing the stdout and stderr files.

인자 없이 감사 이벤트 cpython._PySys_ClearAuditHooks 를 발생시킵니다.

Added in version 3.6.

void Py_Finalize()

Part of the Stable ABI.

이것은 Py_FinalizeEx()의 이전 버전과 호환되는 반환 값을 무시하는 버전입니다.

int Py_BytesMain(int argc, char **argv)

Part of the Stable ABI since version 3.8.

Similar to Py_Main() but argv is an array of bytes strings, allowing the calling application to delegate the text decoding step to the CPython runtime.

Added in version 3.8.

int Py_Main(int argc, wchar_t **argv)

Part of the Stable ABI.

The main program for the standard interpreter, encapsulating a full initialization/finalization cycle, as well as additional behaviour to implement reading configurations settings from the environment and command line, and then executing __main__ in accordance with 명령 줄.

This is made available for programs which wish to support the full CPython command line interface, rather than just embedding a Python runtime in a larger application.

The argc and argv parameters are similar to those which are passed to a C program’s main() function, except that the argv entries are first converted to wchar_t using Py_DecodeLocale(). It is also important to note that the argument list entries may be modified to point to strings other than those passed in (however, the contents of the strings pointed to by the argument list are not modified).

The return value will be 0 if the interpreter exits normally (i.e., without an exception), 1 if the interpreter exits due to an exception, or 2 if the argument list does not represent a valid Python command line.

Note that if an otherwise unhandled SystemExit is raised, this function will not return 1, but exit the process, as long as Py_InspectFlag is not set. If Py_InspectFlag is set, execution will drop into the interactive Python prompt, at which point a second otherwise unhandled SystemExit will still exit the process, while any other means of exiting will set the return value as described above.

In terms of the CPython runtime configuration APIs documented in the runtime configuration section (and without accounting for error handling), Py_Main is approximately equivalent to:

PyConfig config;
PyConfig_InitPythonConfig(&config);
PyConfig_SetArgv(&config, argc, argv);
Py_InitializeFromConfig(&config);
PyConfig_Clear(&config);

Py_RunMain();

In normal usage, an embedding application will call this function instead of calling Py_Initialize(), Py_InitializeEx() or Py_InitializeFromConfig() directly, and all settings will be applied as described elsewhere in this documentation. If this function is instead called after a preceding runtime initialization API call, then exactly which environmental and command line configuration settings will be updated is version dependent (as it depends on which settings correctly support being modified after they have already been set once when the runtime was first initialized).

int Py_RunMain(void)

Executes the main module in a fully configured CPython runtime.

Executes the command (PyConfig.run_command), the script (PyConfig.run_filename) or the module (PyConfig.run_module) specified on the command line or in the configuration. If none of these values are set, runs the interactive Python prompt (REPL) using the __main__ module’s global namespace.

If PyConfig.inspect is not set (the default), the return value will be 0 if the interpreter exits normally (that is, without raising an exception), or 1 if the interpreter exits due to an exception. If an otherwise unhandled SystemExit is raised, the function will immediately exit the process instead of returning 1.

If PyConfig.inspect is set (such as when the -i option is used), rather than returning when the interpreter exits, execution will instead resume in an interactive Python prompt (REPL) using the __main__ module’s global namespace. If the interpreter exited with an exception, it is immediately raised in the REPL session. The function return value is then determined by the way the REPL session terminates: returning 0 if the session terminates without raising an unhandled exception, exiting immediately for an unhandled SystemExit, and returning 1 for any other unhandled exception.

This function always finalizes the Python interpreter regardless of whether it returns a value or immediately exits the process due to an unhandled SystemExit exception.

See Python Configuration for an example of a customized Python that always runs in isolated mode using Py_RunMain().

프로세스 전체 매개 변수

void Py_SetProgramName(const wchar_t *name)

Part of the Stable ABI.

This API is kept for backward compatibility: setting PyConfig.program_name should be used instead, see Python Initialization Configuration.

(호출된다면) 이 함수는 Py_Initialize()가 처음으로 호출되기 전에 호출되어야 합니다. 인터프리터에게 프로그램의 main() 함수에 대한 argv[0] 인자의 값을 알려줍니다 (와이드 문자로 변환됩니다). 이것은 Py_GetPath()와 아래의 다른 함수에서 인터프리터 실행 파일과 관련된 파이썬 런타임 라이브러리를 찾는 데 사용됩니다. 기본값은 'python'입니다. 인자는 프로그램을 실행하는 동안 내용이 변경되지 않는 정적 저장소의 0으로 끝나는 와이드 문자열을 가리켜야 합니다. 파이썬 인터프리터의 코드는 이 저장소의 내용을 변경하지 않습니다.

Use Py_DecodeLocale() to decode a bytes string to get a wchar_* string.

버전 3.11부터 폐지됨.

wchar_t *Py_GetProgramName()

Part of the Stable ABI.

Return the program name set with PyConfig.program_name, or the default. The returned string points into static storage; the caller should not modify its value.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get sys.executable instead.

wchar_t *Py_GetPrefix()

Part of the Stable ABI.

Return the prefix for installed platform-independent files. This is derived through a number of complicated rules from the program name set with PyConfig.program_name and some environment variables; for example, if the program name is '/usr/local/bin/python', the prefix is '/usr/local'. The returned string points into static storage; the caller should not modify its value. This corresponds to the prefix variable in the top-level Makefile and the --prefix argument to the configure script at build time. The value is available to Python code as sys.base_prefix. It is only useful on Unix. See also the next function.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get sys.base_prefix instead, or sys.prefix if virtual environments need to be handled.

wchar_t *Py_GetExecPrefix()

Part of the Stable ABI.

Return the exec-prefix for installed platform-dependent files. This is derived through a number of complicated rules from the program name set with PyConfig.program_name and some environment variables; for example, if the program name is '/usr/local/bin/python', the exec-prefix is '/usr/local'. The returned string points into static storage; the caller should not modify its value. This corresponds to the exec_prefix variable in the top-level Makefile and the --exec-prefix argument to the configure script at build time. The value is available to Python code as sys.base_exec_prefix. It is only useful on Unix.

배경: exec-prefix는 플랫폼 종속적 파일(가령 실행 파일과 공유 라이브러리)이 다른 디렉터리 트리에 설치될 때 prefix와 다릅니다. 일반 설치에서, 플랫폼 종속적 파일은 /usr/local/plat 서브 트리에 설치되고 플랫폼 독립적 파일은 /usr/local에 설치될 수 있습니다.

일반적으로 말해서, 플랫폼은 하드웨어와 소프트웨어 제품군의 조합입니다, 예를 들어 Solaris 2.x 운영 체제를 실행하는 Sparc 기계들은 같은 플랫폼으로 간주하지만, Solaris 2.x를 실행하는 Intel 기계는 다른 플랫폼이며, 리눅스를 실행하는 Intel 기계는 또 다른 플랫폼입니다. 같은 운영 체제의 서로 다른 주 개정판도 일반적으로 다른 플랫폼을 형성합니다. 비 유닉스 운영 체제는 다른 이야기입니다; 이러한 시스템의 설치 전략이 너무 다르기 때문에 prefix와 exec-prefix는 의미가 없으며, 빈 문자열로 설정됩니다. 컴파일된 파이썬 바이트 코드 파일은 플랫폼 독립적임에 유의하십시오 (그러나 이들을 컴파일하는데 사용된 파이썬 버전에는 종속적입니다!).

시스템 관리자는 /usr/local/plat을 각 플랫폼에 대해 다른 파일 시스템으로 사용하면서 플랫폼 간에 /usr/local을 공유하도록 mount나 automount 프로그램을 구성하는 방법을 알 것입니다.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get sys.base_exec_prefix instead, or sys.exec_prefix if virtual environments need to be handled.

wchar_t *Py_GetProgramFullPath()

Part of the Stable ABI.

Return the full program name of the Python executable; this is computed as a side-effect of deriving the default module search path from the program name (set by PyConfig.program_name). The returned string points into static storage; the caller should not modify its value. The value is available to Python code as sys.executable.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get sys.executable instead.

wchar_t *Py_GetPath()

Part of the Stable ABI.

Return the default module search path; this is computed from the program name (set by PyConfig.program_name) and some environment variables. The returned string consists of a series of directory names separated by a platform dependent delimiter character. The delimiter character is ':' on Unix and macOS, ';' on Windows. The returned string points into static storage; the caller should not modify its value. The list sys.path is initialized with this value on interpreter startup; it can be (and usually is) modified later to change the search path for loading modules.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get sys.path instead.

const char *Py_GetVersion()

Part of the Stable ABI.

이 파이썬 인터프리터의 버전을 반환합니다. 이것은 다음과 같은 문자열입니다

"3.0a5+ (py3k:63103M, May 12 2008, 00:53:55) \n[GCC 4.2.3]"

The first word (up to the first space character) is the current Python version; the first characters are the major and minor version separated by a period. The returned string points into static storage; the caller should not modify its value. The value is available to Python code as sys.version.

See also the Py_Version constant.

const char *Py_GetPlatform()

Part of the Stable ABI.

Return the platform identifier for the current platform. On Unix, this is formed from the “official” name of the operating system, converted to lower case, followed by the major revision number; e.g., for Solaris 2.x, which is also known as SunOS 5.x, the value is 'sunos5'. On macOS, it is 'darwin'. On Windows, it is 'win'. The returned string points into static storage; the caller should not modify its value. The value is available to Python code as sys.platform.

const char *Py_GetCopyright()

Part of the Stable ABI.

현재 파이썬 버전에 대한 공식 저작권 문자열을 반환합니다, 예를 들어

'Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam'

반환된 문자열은 정적 저장소를 가리킵니다; 호출자는 값을 수정해서는 안 됩니다. 이 값은 파이썬 코드에서 sys.copyright로 사용할 수 있습니다.

const char *Py_GetCompiler()

Part of the Stable ABI.

현재 파이썬 버전을 빌드하는 데 사용된 컴파일러 표시를 대괄호 감싸서 반환합니다, 예를 들면:

"[GCC 2.7.2.2]"

반환된 문자열은 정적 저장소를 가리킵니다; 호출자는 값을 수정해서는 안 됩니다. 이 값은 파이썬 코드에서 변수 sys.version의 일부로 제공됩니다.

const char *Py_GetBuildInfo()

Part of the Stable ABI.

현재 파이썬 인터프리터 인스턴스의 시퀀스 번호와 빌드 날짜 및 시간에 대한 정보를 반환합니다, 예를 들어

"#67, Aug  1 1997, 22:34:28"

반환된 문자열은 정적 저장소를 가리킵니다; 호출자는 값을 수정해서는 안 됩니다. 이 값은 파이썬 코드에서 변수 sys.version의 일부로 제공됩니다.

void PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)

Part of the Stable ABI.

This API is kept for backward compatibility: setting PyConfig.argv, PyConfig.parse_argv and PyConfig.safe_path should be used instead, see Python Initialization Configuration.

argc 및 argv에 기반해서 sys.argv를 설정합니다. 이 매개 변수는 프로그램의 main() 함수에 전달된 것과 유사하지만, 첫 번째 항목이 파이썬 인터프리터를 호스팅하는 실행 파일이 아니라 실행될 스크립트 파일을 참조해야 한다는 차이점이 있습니다. 실행할 스크립트가 없으면, argv의 첫 번째 항목은 빈 문자열일 수 있습니다. 이 함수가 sys.argv 초기화에 실패하면, Py_FatalError()를 사용하여 치명적인 조건을 표시합니다.

updatepath가 0이면, 여기까지가 이 함수가 하는 모든 일입니다. updatepath가 0이 아니면, 함수는 다음 알고리즘에 따라 sys.path도 수정합니다:

기존 스크립트의 이름이 argv[0]으로 전달되면, 스크립트가 있는 디렉터리의 절대 경로가 sys.path 앞에 추가됩니다.

그렇지 않으면 (즉, argc가 0이거나 argv[0]이 기존 파일 이름을 가리키지 않으면), sys.path 앞에 빈 문자열이 추가됩니다, 이는 현재 작업 디렉터리(".")를 앞에 추가하는 것과 같습니다.

Use Py_DecodeLocale() to decode a bytes string to get a wchar_* string.

See also PyConfig.orig_argv and PyConfig.argv members of the Python Initialization Configuration.

참고

It is recommended that applications embedding the Python interpreter for purposes other than executing a single script pass 0 as updatepath, and update sys.path themselves if desired. See CVE 2008-5983 [https://www.cve.org/CVERecord?id=CVE-2008-5983].

3.1.3 이전 버전에서는, PySys_SetArgv()를 호출한 후 첫 번째 sys.path 요소를 수동으로 제거하여 같은 효과를 얻을 수 있습니다, 예를 들어 다음을 사용하여:

PyRun_SimpleString("import sys; sys.path.pop(0)\n");

Added in version 3.1.3.

버전 3.11부터 폐지됨.

void PySys_SetArgv(int argc, wchar_t **argv)

Part of the Stable ABI.

This API is kept for backward compatibility: setting PyConfig.argv and PyConfig.parse_argv should be used instead, see Python Initialization Configuration.

이 함수는 python 인터프리터가 -I로 시작되지 않는 한 updatepath가 1로 설정된 PySys_SetArgvEx()처럼 작동합니다.

Use Py_DecodeLocale() to decode a bytes string to get a wchar_* string.

See also PyConfig.orig_argv and PyConfig.argv members of the Python Initialization Configuration.

버전 3.4에서 변경: updatepath 값은 -I에 따라 다릅니다.

버전 3.11부터 폐지됨.

void Py_SetPythonHome(const wchar_t *home)

Part of the Stable ABI.

This API is kept for backward compatibility: setting PyConfig.home should be used instead, see Python Initialization Configuration.

기본 “홈” 디렉터리, 즉 표준 파이썬 라이브러리의 위치를 설정합니다. 인자 문자열의 의미는 PYTHONHOME 을 참조하십시오.

인자는 프로그램을 실행하는 동안 내용이 변경되지 않는 정적 저장소에 있는 0으로 끝나는 문자열을 가리켜야 합니다. 파이썬 인터프리터의 코드는 이 저장소의 내용을 변경하지 않습니다.

Use Py_DecodeLocale() to decode a bytes string to get a wchar_* string.

버전 3.11부터 폐지됨.

wchar_t *Py_GetPythonHome()

Part of the Stable ABI.

Return the default “home”, that is, the value set by PyConfig.home, or the value of the PYTHONHOME environment variable if it is set.

This function should not be called before Py_Initialize(), otherwise it returns NULL.

버전 3.10에서 변경: It now returns NULL if called before Py_Initialize().

Deprecated since version 3.13, will be removed in version 3.15: Get PyConfig.home or PYTHONHOME environment variable instead.

스레드 상태와 전역 인터프리터 록

파이썬 인터프리터는 완전히 스레드 안전하지 않습니다. 다중 스레드 파이썬 프로그램을 지원하기 위해, 파이썬 객체에 안전하게 액세스하기 전에 현재 스레드가 보유해야 하는 전역 인터프리터 록 혹은 GIL이라고 하는 전역 록이 있습니다. 록 없이는, 가장 간단한 연산조차도 다중 스레드 프로그램에서 문제를 일으킬 수 있습니다: 예를 들어, 두 스레드가 동시에 같은 객체의 참조 횟수를 증가시키면, 참조 횟수가 두 번이 아닌 한 번만 증가할 수 있습니다.

따라서, GIL을 획득한 스레드만 파이썬 객체에서 작동하거나 파이썬/C API 함수를 호출할 수 있다는 규칙이 있습니다. 동시 실행을 모방하기 위해 인터프리터는 정기적으로 스레드 전환을 시도합니다 (sys.setswitchinterval()을 참조하십시오). 록은 파일 읽기나 쓰기와 같은 잠재적인 블로킹 I/O 연산에 대해서도 해제되므로, 그동안 다른 파이썬 스레드가 실행될 수 있습니다.

파이썬 인터프리터는 PyThreadState 라는 데이터 구조체 내에 스레드 별 부기(bookkeeping) 정보를 보관합니다. 현재 PyThreadState 를 가리키는 하나의 전역 변수도 있습니다: PyThreadState_Get()을 사용하여 얻을 수 있습니다.

확장 코드에서 GIL 해제하기

GIL을 조작하는 대부분의 확장 코드는 다음과 같은 간단한 구조로 되어 있습니다:

Save the thread state in a local variable.
Release the global interpreter lock.
... Do some blocking I/O operation ...
Reacquire the global interpreter lock.
Restore the thread state from the local variable.

이것은 매우 일반적이어서 이를 단순화하기 위해 한 쌍의 매크로가 존재합니다:

Py_BEGIN_ALLOW_THREADS
... Do some blocking I/O operation ...
Py_END_ALLOW_THREADS

Py_BEGIN_ALLOW_THREADS 매크로는 새 블록을 열고 숨겨진 지역 변수를 선언합니다; Py_END_ALLOW_THREADS 매크로는 블록을 닫습니다.

위의 블록은 다음 코드로 확장됩니다:

PyThreadState *_save;

_save = PyEval_SaveThread();
... Do some blocking I/O operation ...
PyEval_RestoreThread(_save);

이 함수들의 작동 방식은 다음과 같습니다: 전역 인터프리터 록이 현재 스레드 상태에 대한 포인터를 보호하는 데 사용됩니다. 록을 해제하고 스레드 상태를 저장할 때, 록이 해제되기 전에 현재 스레드 상태 포인터를 가져와야 합니다 (다른 스레드가 즉시 록을 획득하고 전역 변수에 자신의 스레드 상태를 저장할 수 있기 때문입니다). 반대로, 록을 획득하고 스레드 상태를 복원할 때, 스레드 상태 포인터를 저장하기 전에 록을 획득해야 합니다.

참고

시스템 I/O 함수 호출은 GIL을 릴리스하는 가장 일반적인 사용 사례이지만, 메모리 버퍼를 통해 작동하는 압축이나 암호화 함수와 같이, 파이썬 객체에 액세스할 필요가 없는 장기 실행 계산을 호출하기 전에도 유용할 수 있습니다. 예를 들어, 표준 zlib와 hashlib 모듈은 데이터를 압축하거나 해싱할 때 GIL을 해제합니다.

파이썬이 만들지 않은 스레드

전용 파이썬 API(가령 threading 모듈)를 사용하여 스레드를 만들면, 스레드 상태가 자동으로 연결되므로 위에 표시된 코드가 올바릅니다. 그러나, 스레드가 C에서 만들어질 때 (예를 들어 자체 스레드 관리 기능이 있는 제삼자 라이브러리에 의해), GIL을 보유하지 않고, 그들을 위한 스레드 상태 구조도 없습니다.

이러한 스레드에서 파이썬 코드를 호출해야 하면 (종종 앞서 언급한 제삼자 라이브러리에서 제공하는 콜백 API의 일부가 됩니다), 먼저 스레드 상태 자료 구조를 만들어서 인터프리터에 이러한 스레드를 등록한 다음, GIL을 획득하고, 마지막으로 파이썬/C API 사용을 시작하기 전에 스레드 상태 포인터를 저장합니다. 완료되면, 스레드 상태 포인터를 재설정하고, GIL을 해제한 다음, 마지막으로 스레드 상태 자료 구조를 해제해야 합니다.

PyGILState_Ensure()와 PyGILState_Release() 함수는 위의 모든 작업을 자동으로 수행합니다. C 스레드에서 파이썬을 호출하는 일반적인 관용구는 다음과 같습니다:

PyGILState_STATE gstate;
gstate = PyGILState_Ensure();

/* Perform Python actions here. */
result = CallSomeFunction();
/* evaluate result or handle exception */

/* Release the thread. No Python API allowed beyond this point. */
PyGILState_Release(gstate);

Note that the PyGILState_* functions assume there is only one global interpreter (created automatically by Py_Initialize()). Python supports the creation of additional interpreters (using Py_NewInterpreter()), but mixing multiple interpreters and the PyGILState_* API is unsupported.

fork()에 대한 주의 사항

스레드에 대해 주목해야 할 또 다른 중요한 점은 C fork() 호출 시 스레드의 동작입니다. fork()를 사용하는 대부분의 시스템에서는, 프로세스가 포크한 후에 포크를 발행한 스레드만 존재합니다. 이는 록을 처리해야 하는 방법과 CPython 런타임에 저장된 모든 상태 모두에 구체적인 영향을 미칩니다.

The fact that only the “current” thread remains means any locks held by other threads will never be released. Python solves this for os.fork() by acquiring the locks it uses internally before the fork, and releasing them afterwards. In addition, it resets any Lock 객체 in the child. When extending or embedding Python, there is no way to inform Python of additional (non-Python) locks that need to be acquired before or reset after a fork. OS facilities such as pthread_atfork() would need to be used to accomplish the same thing. Additionally, when extending or embedding Python, calling fork() directly rather than through os.fork() (and returning to or calling into Python) may result in a deadlock by one of Python’s internal locks being held by a thread that is defunct after the fork. PyOS_AfterFork_Child() tries to reset the necessary locks, but is not always able to.

다른 모든 스레드가 사라진다는 사실은 또한 CPython의 런타임 상태가 os.fork()와 마찬가지로 적절하게 정리되어야 함을 의미합니다. 이것은 현재 인터프리터와 다른 모든 PyInterpreterState 객체에 속하는 다른 모든 PyThreadState 객체를 파이널리제이션 하는 것을 의미합니다. 이것과 “메인” 인터프리터의 특수한 특성으로 인해, fork()는 CPython 전역 런타임이 원래 초기화된 인터프리터의 “메인” 스레드에서만 호출되어야 합니다. 유일한 예외는 exec()가 그 후에 즉시 호출되는 경우입니다.

Cautions regarding runtime finalization

In the late stage of interpreter shutdown, after attempting to wait for non-daemon threads to exit (though this can be interrupted by KeyboardInterrupt) and running the atexit functions, the runtime is marked as finalizing: _Py_IsFinalizing() and sys.is_finalizing() return true. At this point, only the finalization thread that initiated finalization (typically the main thread) is allowed to acquire the GIL.

If any thread, other than the finalization thread, attempts to acquire the GIL during finalization, either explicitly via PyGILState_Ensure(), Py_END_ALLOW_THREADS, PyEval_AcquireThread(), or PyEval_AcquireLock(), or implicitly when the interpreter attempts to reacquire it after having yielded it, the thread enters a permanently blocked state where it remains until the program exits. In most cases this is harmless, but this can result in deadlock if a later stage of finalization attempts to acquire a lock owned by the blocked thread, or otherwise waits on the blocked thread.

Gross? Yes. This prevents random crashes and/or unexpectedly skipped C++ finalizations further up the call stack when such threads were forcibly exited here in CPython 3.13 and earlier. The CPython runtime GIL acquiring C APIs have never had any error reporting or handling expectations at GIL acquisition time that would’ve allowed for graceful exit from this situation. Changing that would require new stable C APIs and rewriting the majority of C code in the CPython ecosystem to use those with error handling.

고수준 API

다음은 C 확장 코드를 작성하거나 파이썬 인터프리터를 내장할 때 가장 일반적으로 사용되는 형과 함수입니다:

type PyInterpreterState

Part of the Limited API (as an opaque struct).

이 자료 구조는 여러 협력 스레드가 공유하는 상태를 나타냅니다. 같은 인터프리터에 속하는 스레드는 모듈 관리와 몇 가지 다른 내부 항목을 공유합니다. 이 구조체에는 공개 멤버가 없습니다.

다른 인터프리터에 속한 스레드는 사용 가능한 메모리, 열린 파일 기술자 등과 같은 프로세스 상태를 제외하고는, 처음에는 아무것도 공유하지 않습니다. 전역 인터프리터 록은 어떤 인터프리터에 속해 있는지에 관계없이 모든 스레드에서 공유됩니다.

type PyThreadState

Part of the Limited API (as an opaque struct).

This data structure represents the state of a single thread. The only public data member is:

PyInterpreterState *interp

This thread’s interpreter state.

void PyEval_InitThreads()

Part of the Stable ABI.

아무것도 하지 않는 폐지된 함수.

파이썬 3.6과 이전 버전에서는, 이 함수가 존재하지 않으면 GIL을 만들었습니다.

버전 3.9에서 변경: 이제 이 함수는 아무 작업도 수행하지 않습니다.

버전 3.7에서 변경: 이 함수는 이제 Py_Initialize()에 의해 호출되어서, 여러분은 더는 직접 호출할 필요가 없습니다.

버전 3.2에서 변경: 이 함수는 더는 Py_Initialize() 전에 호출할 수 없습니다.

버전 3.9부터 폐지됨.

PyThreadState *PyEval_SaveThread()

Part of the Stable ABI.

(만들었다면) 전역 인터프리터 록을 해제하고 스레드 상태를 NULL로 재설정하고, 이전 스레드 상태(NULL이 아닙니다)를 반환합니다. 록이 만들어졌다면, 현재 스레드가 록을 획득했어야 합니다.

void PyEval_RestoreThread(PyThreadState *tstate)

Part of the Stable ABI.

(만들었다면) 전역 인터프리터 록을 획득하고 스레드 상태를 NULL이 아니어야 하는 tstate로 설정합니다. 록이 만들어졌다면, 현재 스레드가 이를 획득하지 않았어야 합니다, 그렇지 않으면 교착 상태가 발생합니다.

참고

Calling this function from a thread when the runtime is finalizing will hang the thread until the program exits, even if the thread was not created by Python. Refer to Cautions regarding runtime finalization for more details.

버전 3.14에서 변경: Hangs the current thread, rather than terminating it, if called while the interpreter is finalizing.

PyThreadState *PyThreadState_Get()

Part of the Stable ABI.

현재 스레드 상태를 반환합니다. 전역 인터프리터 록을 보유해야 합니다. 현재 스레드 상태가 NULL이면 치명적인 에러가 발생합니다 (그래서 호출자가 NULL을 확인할 필요가 없습니다).

See also PyThreadState_GetUnchecked().

PyThreadState *PyThreadState_GetUnchecked()

Similar to PyThreadState_Get(), but don’t kill the process with a fatal error if it is NULL. The caller is responsible to check if the result is NULL.

Added in version 3.13: In Python 3.5 to 3.12, the function was private and known as _PyThreadState_UncheckedGet().

PyThreadState *PyThreadState_Swap(PyThreadState *tstate)

Part of the Stable ABI.

현재 스레드 상태를 인자 tstate(NULL일 수 있습니다)가 제공하는 스레드 상태와 스와프합니다. 전역 인터프리터 록을 보유해야 하며 해제되지 않습니다.

다음 함수는 스레드 로컬 저장소를 사용하며, 서브 인터프리터와 호환되지 않습니다:

PyGILState_STATE PyGILState_Ensure()

Part of the Stable ABI.

현재 스레드가 파이썬의 현재 상태나 전역 인터프리터 록과 관계없이 파이썬 C API를 호출할 준비가 되었는지 확인합니다. 이것은 각 호출이 PyGILState_Release()에 대한 호출과 쌍을 이루는 한 스레드에서 원하는 만큼 여러 번 호출될 수 있습니다. 일반적으로, 스레드 상태가 Release() 전에 이전 상태로 복원되는 한 PyGILState_Ensure()와 PyGILState_Release() 호출 간에 다른 스레드 관련 API를 사용할 수 있습니다. 예를 들어, Py_BEGIN_ALLOW_THREADS와 Py_END_ALLOW_THREADS 매크로의 정상적인 사용은 허용됩니다.

반환 값은 PyGILState_Ensure()가 호출되었을 때의 스레드 상태에 대한 불투명한 “핸들”이며, 파이썬이 같은 상태에 있도록 하려면 PyGILState_Release()로 전달되어야 합니다. 재귀 호출이 허용되더라도, 이 핸들들은 공유할 수 없습니다 - PyGILState_Ensure()에 대한 각 고유 호출은 자신의 PyGILState_Release()에 대한 호출을 위해 핸들을 저장해야 합니다.

함수가 반환할 때, 현재 스레드는 GIL을 보유하고 임의의 파이썬 코드를 호출할 수 있습니다. 실패는 치명적인 에러입니다.

참고

Calling this function from a thread when the runtime is finalizing will hang the thread until the program exits, even if the thread was not created by Python. Refer to Cautions regarding runtime finalization for more details.

버전 3.14에서 변경: Hangs the current thread, rather than terminating it, if called while the interpreter is finalizing.

void PyGILState_Release(PyGILState_STATE)

Part of the Stable ABI.

이전에 획득 한 모든 자원을 해제합니다. 이 호출 후에, 파이썬의 상태는 해당 PyGILState_Ensure() 호출 이전과 같습니다 (그러나 일반적으로 이 상태는 호출자에게 알려지지 않아서, GILState API를 사용합니다).

PyGILState_Ensure()에 대한 모든 호출은 같은 스레드에서 PyGILState_Release()에 대한 호출과 쌍을 이뤄야 합니다.

PyThreadState *PyGILState_GetThisThreadState()

Part of the Stable ABI.

이 스레드의 현재 스레드 상태를 가져옵니다. 현재 스레드에서 GILState API가 사용되지 않았으면 NULL을 반환할 수 있습니다. 메인 스레드에서 자동 스레드 상태 호출(auto-thread-state call)이 수행되지 않은 경우에도, 메인 스레드에는 항상 이러한 스레드 상태가 있음에 유의하십시오. 이것은 주로 도우미/진단 함수입니다.

int PyGILState_Check()

현재 스레드가 GIL을 보유하고 있으면 1을 반환하고 그렇지 않으면 0을 반환합니다. 이 함수는 아무 때나 모든 스레드에서 호출할 수 있습니다. 파이썬 스레드 상태가 초기화되었고 현재 GIL을 보유하고 있을 때만 1을 반환합니다. 이것은 주로 도우미/진단 함수입니다. 예를 들어 콜백 컨텍스트나 메모리 할당 함수에서 유용할 수 있는데, GIL이 잠겨 있다는 것을 알면 호출자가 민감한 작업을 수행하거나 그렇지 않으면 다르게 동작하도록 할 수 있습니다.

Added in version 3.4.

다음 매크로는 일반적으로 후행 세미콜론 없이 사용됩니다; 파이썬 소스 배포에서 사용 예를 찾으십시오.

Py_BEGIN_ALLOW_THREADS

Part of the Stable ABI.

이 매크로는 { PyThreadState *_save; _save = PyEval_SaveThread(); 로 확장됩니다. 여는 중괄호가 포함되어 있음에 유의하십시오; 뒤따르는 Py_END_ALLOW_THREADS 매크로와 일치해야 합니다. 이 매크로에 대한 자세한 내용은 위를 참조하십시오.

Py_END_ALLOW_THREADS

Part of the Stable ABI.

이 매크로는 PyEval_RestoreThread(_save); }로 확장됩니다. 닫는 중괄호가 포함되어 있음에 유의하십시오; 이전 Py_BEGIN_ALLOW_THREADS 매크로와 일치해야 합니다. 이 매크로에 대한 자세한 내용은 위를 참조하십시오.

Py_BLOCK_THREADS

Part of the Stable ABI.

이 매크로는 PyEval_RestoreThread(_save); 로 확장됩니다: 닫는 중괄호가 없는 Py_END_ALLOW_THREADS와 동등합니다.

Py_UNBLOCK_THREADS

Part of the Stable ABI.

이 매크로는 _save = PyEval_SaveThread(); 로 확장됩니다: 여는 중괄호와 변수 선언이 없는 Py_BEGIN_ALLOW_THREADS와 동등합니다.

저수준 API

다음 함수는 모두 Py_Initialize() 이후에 호출되어야 합니다.

버전 3.7에서 변경: Py_Initialize()는 이제 GIL을 초기화합니다.

PyInterpreterState *PyInterpreterState_New()

Part of the Stable ABI.

새 인터프리터 상태 객체를 만듭니다. 전역 인터프리터 록을 보유할 필요는 없지만, 이 함수에 대한 호출을 직렬화해야 하면 보유할 수 있습니다.

인자 없이 감사 이벤트 cpython.PyInterpreterState_New를 발생시킵니다.

void PyInterpreterState_Clear(PyInterpreterState *interp)

Part of the Stable ABI.

인터프리터 상태 객체의 모든 정보를 재설정합니다. 전역 인터프리터 록을 보유해야 합니다.

인자 없이 감사 이벤트 cpython.PyInterpreterState_Clear를 발생시킵니다.

void PyInterpreterState_Delete(PyInterpreterState *interp)

Part of the Stable ABI.

인터프리터 상태 객체를 파괴합니다. 전역 인터프리터 록은 보유할 필요 없습니다. 인터프리터 상태는 PyInterpreterState_Clear()에 대한 이전 호출로 재설정되었어야 합니다.

PyThreadState *PyThreadState_New(PyInterpreterState *interp)

Part of the Stable ABI.

주어진 인터프리터 객체에 속하는 새 스레드 상태 객체를 만듭니다. 전역 인터프리터 록을 보유할 필요는 없지만, 이 함수에 대한 호출을 직렬화해야 하면 보유할 수 있습니다.

void PyThreadState_Clear(PyThreadState *tstate)

Part of the Stable ABI.

스레드 상태 객체의 모든 정보를 재설정합니다. 전역 인터프리터 록을 보유해야 합니다.

버전 3.9에서 변경: 이 함수는 이제 PyThreadState.on_delete 콜백을 호출합니다. 이전에는, PyThreadState_Delete()에서 호출했습니다.

버전 3.13에서 변경: The PyThreadState.on_delete callback was removed.

void PyThreadState_Delete(PyThreadState *tstate)

Part of the Stable ABI.

스레드 상태 객체를 파괴합니다. 전역 인터프리터 록은 보유할 필요 없습니다. 스레드 상태는 PyThreadState_Clear()에 대한 이전 호출로 재설정되었어야 합니다.

void PyThreadState_DeleteCurrent(void)

Destroy the current thread state and release the global interpreter lock. Like PyThreadState_Delete(), the global interpreter lock must be held. The thread state must have been reset with a previous call to PyThreadState_Clear().

PyFrameObject *PyThreadState_GetFrame(PyThreadState *tstate)

Part of the Stable ABI since version 3.10.

파이썬 스레드 상태 tstate의 현재 프레임을 가져옵니다.

Return a strong reference. Return NULL if no frame is currently executing.

PyEval_GetFrame()도 참조하십시오.

tstate는 NULL이 아니어야 합니다.

Added in version 3.9.

uint64_t PyThreadState_GetID(PyThreadState *tstate)

Part of the Stable ABI since version 3.10.

파이썬 스레드 상태 tstate의 고유한 스레드 상태 식별자를 가져옵니다.

tstate는 NULL이 아니어야 합니다.

Added in version 3.9.

PyInterpreterState *PyThreadState_GetInterpreter(PyThreadState *tstate)

Part of the Stable ABI since version 3.10.

파이썬 스레드 상태 tstate의 인터프리터를 가져옵니다.

tstate는 NULL이 아니어야 합니다.

Added in version 3.9.

void PyThreadState_EnterTracing(PyThreadState *tstate)

Suspend tracing and profiling in the Python thread state tstate.

Resume them using the PyThreadState_LeaveTracing() function.

Added in version 3.11.

void PyThreadState_LeaveTracing(PyThreadState *tstate)

Resume tracing and profiling in the Python thread state tstate suspended by the PyThreadState_EnterTracing() function.

See also PyEval_SetTrace() and PyEval_SetProfile() functions.

Added in version 3.11.

PyInterpreterState *PyInterpreterState_Get(void)

Part of the Stable ABI since version 3.9.

현재 인터프리터를 가져옵니다.

현재 파이썬 스레드 상태가 없거나 현재 인터프리터가 없으면 치명적인 에러를 발행합니다. NULL을 반환할 수 없습니다.

호출자는 GIL을 보유해야 합니다.

Added in version 3.9.

int64_t PyInterpreterState_GetID(PyInterpreterState *interp)

Part of the Stable ABI since version 3.7.

인터프리터의 고유 ID를 반환합니다. 그렇게 하는데 에러가 발생하면 -1이 반환되고 에러가 설정됩니다.

호출자는 GIL을 보유해야 합니다.

Added in version 3.7.

PyObject *PyInterpreterState_GetDict(PyInterpreterState *interp)

Part of the Stable ABI since version 3.8.

인터프리터별 데이터가 저장될 수 있는 딕셔너리를 반환합니다. 이 함수가 NULL을 반환하면 예외는 발생하지 않았고 호출자는 인터프리터별 딕셔너리를 사용할 수 없다고 가정해야 합니다.

이것은 확장이 인터프리터별 상태 정보를 저장하는 데 사용해야 하는 PyModule_GetState()를 대체하는 것이 아닙니다.

Added in version 3.8.

typedef PyObject *(*_PyFrameEvalFunction)(PyThreadState *tstate, _PyInterpreterFrame *frame, int throwflag)

프레임 평가 함수의 형.

throwflag 매개 변수는 제너레이터의 throw() 메서드에서 사용됩니다: 0이 아니면, 현재 예외를 처리합니다.

버전 3.9에서 변경: 이제 함수는 tstate 매개 변수를 취합니다.

버전 3.11에서 변경: The frame parameter changed from PyFrameObject* to _PyInterpreterFrame*.

_PyFrameEvalFunction _PyInterpreterState_GetEvalFrameFunc(PyInterpreterState *interp)

프레임 평가 함수를 가져옵니다.

PEP 523 [https://peps.python.org/pep-0523/] “CPython에 프레임 평가 API 추가”를 참조하십시오.

Added in version 3.9.

void _PyInterpreterState_SetEvalFrameFunc(PyInterpreterState *interp, _PyFrameEvalFunction eval_frame)

프레임 평가 함수를 설정합니다.

PEP 523 [https://peps.python.org/pep-0523/] “CPython에 프레임 평가 API 추가”를 참조하십시오.

Added in version 3.9.

PyObject *PyThreadState_GetDict()

Return value: Borrowed reference. Part of the Stable ABI.

확장이 스레드별 상태 정보를 저장할 수 있는 딕셔너리를 반환합니다. 각 확장은 딕셔너리에 상태를 저장하는 데 사용할 고유 키를 사용해야 합니다. 현재 스레드 상태를 사용할 수 없을 때 이 함수를 호출해도 됩니다. 이 함수가 NULL을 반환하면, 예외는 발생하지 않았고 호출자는 현재 스레드 상태를 사용할 수 없다고 가정해야 합니다.

int PyThreadState_SetAsyncExc(unsigned long id, PyObject *exc)

Part of the Stable ABI.

Asynchronously raise an exception in a thread. The id argument is the thread id of the target thread; exc is the exception object to be raised. This function does not steal any references to exc. To prevent naive misuse, you must write your own C extension to call this. Must be called with the GIL held. Returns the number of thread states modified; this is normally one, but will be zero if the thread id isn’t found. If exc is NULL, the pending exception (if any) for the thread is cleared. This raises no exceptions.

버전 3.7에서 변경: The type of the id parameter changed from long to unsigned long.

void PyEval_AcquireThread(PyThreadState *tstate)

Part of the Stable ABI.

전역 인터프리터 록을 획득하고 현재 스레드 상태를 tstate로 설정합니다. tstate는 NULL이 아니어야 합니다. 록은 이전에 만들어진 것이어야 합니다. 이 스레드에 이미 록이 있으면, 교착 상태가 발생합니다.

참고

Calling this function from a thread when the runtime is finalizing will hang the thread until the program exits, even if the thread was not created by Python. Refer to Cautions regarding runtime finalization for more details.

버전 3.8에서 변경: PyEval_RestoreThread(), Py_END_ALLOW_THREADS() 및 PyGILState_Ensure()와 일관되도록 갱신되었으며, 인터프리터가 파이널리제이션 하는 동안 호출되면 현재 스레드를 종료합니다.

버전 3.14에서 변경: Hangs the current thread, rather than terminating it, if called while the interpreter is finalizing.

PyEval_RestoreThread()는 (스레드가 초기화되지 않았을 때조차) 항상 사용할 수 있는 고수준 함수입니다.

void PyEval_ReleaseThread(PyThreadState *tstate)

Part of the Stable ABI.

현재 스레드 상태를 NULL로 재설정하고 전역 인터프리터 록을 해제합니다. 록은 이전에 만들어졌어야 하고 현재 스레드가 보유해야 합니다. NULL이 아니어야 하는 tstate 인자는 현재 스레드 상태를 나타내는지 확인하는 데만 사용됩니다 — 그렇지 않으면, 치명적인 에러가 보고됩니다.

PyEval_SaveThread()는 (스레드가 초기화되지 않은 경우에조차) 항상 사용할 수 있는 고수준 함수입니다.

서브 인터프리터 지원

대부분의 경우, 단일 파이썬 인터프리터만 내장할 것입니다만, 같은 프로세스, 어쩌면 같은 스레드에서 여러 독립 인터프리터를 만들어야 하는 경우가 있습니다. 서브 인터프리터는 그렇게 할 수 있도록 합니다.

“메인” 인터프리터는 런타임이 초기화될 때 만들어지는 첫 번째 인터프리터입니다. 보통은 프로세스에서 유일한 파이썬 인터프리터입니다. 서브 인터프리터와 달리, 메인 인터프리터는 시그널 처리와 같은 고유한 프로세스 전역 책임을 갖습니다. 또한 런타임 초기화 동안 실행을 담당하며 일반적으로 런타임 파이널리제이션 동안 활성 인터프리터입니다. PyInterpreterState_Main() 함수는 그것의 상태에 대한 포인터를 반환합니다.

PyThreadState_Swap() 함수를 사용하여 서브 인터프리터 간에 전환할 수 있습니다. 다음 함수를 사용하여 만들고 파괴할 수 있습니다:

type PyInterpreterConfig

Structure containing most parameters to configure a sub-interpreter. Its values are used only in Py_NewInterpreterFromConfig() and never modified by the runtime.

Added in version 3.12.

Structure fields:

int use_main_obmalloc

If this is 0 then the sub-interpreter will use its own “object” allocator state. Otherwise it will use (share) the main interpreter’s.

If this is 0 then check_multi_interp_extensions must be 1 (non-zero). If this is 1 then gil must not be PyInterpreterConfig_OWN_GIL.

int allow_fork

If this is 0 then the runtime will not support forking the process in any thread where the sub-interpreter is currently active. Otherwise fork is unrestricted.

Note that the subprocess module still works when fork is disallowed.

int allow_exec

If this is 0 then the runtime will not support replacing the current process via exec (e.g. os.execv()) in any thread where the sub-interpreter is currently active. Otherwise exec is unrestricted.

Note that the subprocess module still works when exec is disallowed.

int allow_threads

If this is 0 then the sub-interpreter’s threading module won’t create threads. Otherwise threads are allowed.

int allow_daemon_threads

If this is 0 then the sub-interpreter’s threading module won’t create daemon threads. Otherwise daemon threads are allowed (as long as allow_threads is non-zero).

int check_multi_interp_extensions

If this is 0 then all extension modules may be imported, including legacy (single-phase init) modules, in any thread where the sub-interpreter is currently active. Otherwise only multi-phase init extension modules (see PEP 489 [https://peps.python.org/pep-0489/]) may be imported. (Also see Py_mod_multiple_interpreters.)

This must be 1 (non-zero) if use_main_obmalloc is 0.

int gil

This determines the operation of the GIL for the sub-interpreter. It may be one of the following:

PyInterpreterConfig_DEFAULT_GIL

Use the default selection (PyInterpreterConfig_SHARED_GIL).

PyInterpreterConfig_SHARED_GIL

Use (share) the main interpreter’s GIL.

PyInterpreterConfig_OWN_GIL

Use the sub-interpreter’s own GIL.

If this is PyInterpreterConfig_OWN_GIL then PyInterpreterConfig.use_main_obmalloc must be 0.

PyStatus Py_NewInterpreterFromConfig(PyThreadState **tstate_p, const PyInterpreterConfig *config)

새 서브 인터프리터를 만듭니다. 이것은 파이썬 코드 실행을 위한 (거의) 완전히 분리된 환경입니다. 특히, 새 인터프리터에는 기본 모듈 builtins, __main__ 및 sys를 포함하여, 모든 임포트 된 모듈의 개별, 독립 버전을 갖습니다. 로드된 모듈 테이블(sys.modules)과 모듈 검색 경로(sys.path)도 별개입니다. 새 환경에는 sys.argv 변수가 없습니다. 새로운 표준 I/O 스트림 파일 객체 sys.stdin, sys.stdout 및 sys.stderr을 갖습니다 (단, 같은 하부 파일 기술자를 참조합니다).

The given config controls the options with which the interpreter is initialized.

Upon success, tstate_p will be set to the first thread state created in the new sub-interpreter. This thread state is made in the current thread state. Note that no actual thread is created; see the discussion of thread states below. If creation of the new interpreter is unsuccessful, tstate_p is set to NULL; no exception is set since the exception state is stored in the current thread state and there may not be a current thread state.

Like all other Python/C API functions, the global interpreter lock must be held before calling this function and is still held when it returns. Likewise a current thread state must be set on entry. On success, the returned thread state will be set as current. If the sub-interpreter is created with its own GIL then the GIL of the calling interpreter will be released. When the function returns, the new interpreter’s GIL will be held by the current thread and the previously interpreter’s GIL will remain released here.

Added in version 3.12.

Sub-interpreters are most effective when isolated from each other, with certain functionality restricted:

PyInterpreterConfig config = {
    .use_main_obmalloc = 0,
    .allow_fork = 0,
    .allow_exec = 0,
    .allow_threads = 1,
    .allow_daemon_threads = 0,
    .check_multi_interp_extensions = 1,
    .gil = PyInterpreterConfig_OWN_GIL,
};
PyThreadState *tstate = NULL;
PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
if (PyStatus_Exception(status)) {
    Py_ExitStatusException(status);
}

Note that the config is used only briefly and does not get modified. During initialization the config’s values are converted into various PyInterpreterState values. A read-only copy of the config may be stored internally on the PyInterpreterState.

확장 모듈은 다음과 같이 (서브) 인터프리터 간에 공유됩니다:

다단계 초기화를 사용하는 모듈의 경우, 예를 들어 PyModule_FromDefAndSpec(), 각 인터프리터에 대해 별도의 모듈 객체가 만들어지고 초기화됩니다. C 수준 정적과 전역 변수만 이러한 모듈 객체 간에 공유됩니다.

단단계 초기화를 사용하는 모듈의 경우, 예를 들어 PyModule_Create(), 특정 확장이 처음 임포트 될 때, 정상적으로 초기화되고, 모듈 딕셔너리의 (얕은) 사본이 저장됩니다. 다른 (서브) 인터프리터가 같은 확장을 임포트 할 때, 새 모듈이 초기화되고 이 복사본의 내용으로 채워집니다; 확장의 init 함수는 호출되지 않습니다. 따라서 모듈 딕셔너리의 객체는 (서브) 인터프리터 간에 공유되어, 원치 않는 동작을 일으킬 수 있습니다 (아래 버그와 주의 사항을 참조하십시오).

이것은 인터프리터가 Py_FinalizeEx()와 Py_Initialize()를 호출하여 완전히 다시 초기화된 후 확장을 임포트 할 때 일어나는 것과 다름에 유의하십시오; 이 경우, 확장의 initmodule 함수가 다시 호출됩니다. 다단계 초기화와 마찬가지로, 이는 C 수준의 정적과 전역 변수만 이러한 모듈 간에 공유됨을 의미합니다.

PyThreadState *Py_NewInterpreter(void)

Part of the Stable ABI.

Create a new sub-interpreter. This is essentially just a wrapper around Py_NewInterpreterFromConfig() with a config that preserves the existing behavior. The result is an unisolated sub-interpreter that shares the main interpreter’s GIL, allows fork/exec, allows daemon threads, and allows single-phase init modules.

void Py_EndInterpreter(PyThreadState *tstate)

Part of the Stable ABI.

Destroy the (sub-)interpreter represented by the given thread state. The given thread state must be the current thread state. See the discussion of thread states below. When the call returns, the current thread state is NULL. All thread states associated with this interpreter are destroyed. The global interpreter lock used by the target interpreter must be held before calling this function. No GIL is held when it returns.

Py_FinalizeEx() will destroy all sub-interpreters that haven’t been explicitly destroyed at that point.

A Per-Interpreter GIL

Using Py_NewInterpreterFromConfig() you can create a sub-interpreter that is completely isolated from other interpreters, including having its own GIL. The most important benefit of this isolation is that such an interpreter can execute Python code without being blocked by other interpreters or blocking any others. Thus a single Python process can truly take advantage of multiple CPU cores when running Python code. The isolation also encourages a different approach to concurrency than that of just using threads. (See PEP 554 [https://peps.python.org/pep-0554/].)

Using an isolated interpreter requires vigilance in preserving that isolation. That especially means not sharing any objects or mutable state without guarantees about thread-safety. Even objects that are otherwise immutable (e.g. None, (1, 5)) can’t normally be shared because of the refcount. One simple but less-efficient approach around this is to use a global lock around all use of some state (or object). Alternately, effectively immutable objects (like integers or strings) can be made safe in spite of their refcounts by making them immortal. In fact, this has been done for the builtin singletons, small integers, and a number of other builtin objects.

If you preserve isolation then you will have access to proper multi-core computing without the complications that come with free-threading. Failure to preserve isolation will expose you to the full consequences of free-threading, including races and hard-to-debug crashes.

Aside from that, one of the main challenges of using multiple isolated interpreters is how to communicate between them safely (not break isolation) and efficiently. The runtime and stdlib do not provide any standard approach to this yet. A future stdlib module would help mitigate the effort of preserving isolation and expose effective tools for communicating (and sharing) data between interpreters.

Added in version 3.12.

버그와 주의 사항

서브 인터프리터(및 메인 인터프리터)는 같은 프로세스의 일부이기 때문에, 그들 간의 절연이 완벽하지 않습니다 — 예를 들어, os.close()와 같은 저수준 파일 연산을 사용하면 서로의 열린 파일에 (실수로 혹은 악의적으로) 영향을 미칠 수 있습니다. (서브) 인터프리터 간에 확장이 공유되는 방식 때문에, 일부 확장이 제대로 작동하지 않을 수 있습니다; 이것은 특히 단단계 초기화나 (정적) 전역 변수를 사용할 때 특히 그렇습니다. 한 서브 인터프리터에서 만든 객체를 다른 (서브) 인터프리터의 이름 공간에 삽입할 수 있습니다; 가능하면 피해야 합니다.

서브 인터프리터 간에 사용자 정의 함수, 메서드, 인스턴스 또는 클래스를 공유하지 않도록 특별한 주의를 기울여야 합니다. 이러한 객체에 의해 실행되는 임포트 연산은 잘못된 (서브) 인터프리터의 로드된 모듈 딕셔너리에 영향을 미칠 수 있기 때문입니다. 위의 것들에서 접근할 수 있는 객체를 공유하지 않는 것도 마찬가지로 중요합니다.

Also note that combining this functionality with PyGILState_* APIs is delicate, because these APIs assume a bijection between Python thread states and OS-level threads, an assumption broken by the presence of sub-interpreters. It is highly recommended that you don’t switch sub-interpreters between a pair of matching PyGILState_Ensure() and PyGILState_Release() calls. Furthermore, extensions (such as ctypes) using these APIs to allow calling of Python code from non-Python created threads will probably be broken when using sub-interpreters.

비동기 알림

메인 인터프리터 스레드에 비동기 알림을 보내는 메커니즘이 제공됩니다. 이러한 알림은 함수 포인터와 void 포인터 인자의 형태를 취합니다.

int Py_AddPendingCall(int (*func)(void*), void *arg)

Part of the Stable ABI.

메인 인터프리터 스레드에서 호출할 함수를 예약합니다. 성공하면 0이 반환되고 func는 메인 스레드에서 호출되기 위해 큐에 추가됩니다. 실패 시, 예외 설정 없이 -1이 반환됩니다.

성공적으로 큐에 넣으면, func는 arg 인자를 사용하여 결국 메인 인터프리터 스레드에서 호출됩니다. 정상적으로 실행되는 파이썬 코드와 비교할 때 비동기적으로 호출되지만, 다음 두 조건이 모두 충족됩니다:

바이트 코드 경계에서;

메인 스레드가 전역 인터프리터 록을 보유하면서 (따라서 func는 전체 C API를 사용할 수 있습니다).

func는 성공하면 0을, 실패하면 예외 설정과 함께 -1을 반환해야 합니다. func는 다른 비동기 알림을 재귀적으로 수행하기 위해 중단되지 않지만, 전역 인터프리터 록이 해제되면 스레드를 전환하기 위해 여전히 중단될 수 있습니다.

이 함수는 실행하는 데 현재 스레드 상태가 필요하지 않으며, 전역 인터프리터 록이 필요하지 않습니다.

서브 인터프리터에서 이 함수를 호출하려면 호출자가 GIL을 보유해야 합니다. 그렇지 않으면, 함수 func가 잘못된 인터프리터에서 호출되도록 예약될 수 있습니다.

경고

이것은 매우 특별한 경우에만 유용한, 저수준 함수입니다. func가 가능한 한 빨리 호출된다는 보장은 없습니다. 메인 스레드가 시스템 호출을 실행 중이라 바쁘면, 시스템 호출이 반환되기 전에 func가 호출되지 않습니다. 이 함수는 일반적으로 임의의 C 스레드에서 파이썬 코드를 호출하는 데 적합하지 않습니다. 대신, PyGILState API를 사용하십시오.

Added in version 3.1.

버전 3.9에서 변경: 이 함수가 서브 인터프리터에서 호출되면, func 함수는 이제 메인 인터프리터에서 호출되지 않고 서브 인터프리터에서 호출되도록 예약됩니다. 이제 각 서브 인터프리터는 자체 예약된 호출 목록을 갖습니다.

프로파일링과 추적

파이썬 인터프리터는 프로파일링과 실행 추적 기능을 연결하기 위한 몇 가지 저수준 지원을 제공합니다. 프로파일링, 디버깅 및 커버리지 분석 도구에 사용됩니다.

이 C 인터페이스를 사용하면 프로파일링이나 추적 코드가 파이썬 수준의 콜러블 객체를 통해 호출하는 오버헤드를 피하고, 대신 직접 C 함수를 호출할 수 있습니다. 시설의 필수 어트리뷰트는 변경되지 않았습니다; 인터페이스는 추적 함수를 스레드별로 설치할 수 있도록 하며, 추적 함수에 보고되는 기본 이벤트는 이전 버전의 파이썬 수준 추적 함수에 보고된 것과 같습니다.

typedef int (*Py_tracefunc)(PyObject *obj, PyFrameObject *frame, int what, PyObject *arg)

The type of the trace function registered using PyEval_SetProfile() and PyEval_SetTrace(). The first parameter is the object passed to the registration function as obj, frame is the frame object to which the event pertains, what is one of the constants PyTrace_CALL, PyTrace_EXCEPTION, PyTrace_LINE, PyTrace_RETURN, PyTrace_C_CALL, PyTrace_C_EXCEPTION, PyTrace_C_RETURN, or PyTrace_OPCODE, and arg depends on the value of what:

what의 값

arg의 의미

PyTrace_CALL

항상 Py_None.

PyTrace_EXCEPTION

sys.exc_info()에서 반환된 예외 정보.

PyTrace_LINE

항상 Py_None.

PyTrace_RETURN

호출자에게 반환되는 값, 또는 예외로 인한 것이면 NULL.

PyTrace_C_CALL

호출되는 함수 객체.

PyTrace_C_EXCEPTION

호출되는 함수 객체.

PyTrace_C_RETURN

호출되는 함수 객체.

PyTrace_OPCODE

항상 Py_None.

int PyTrace_CALL

함수나 메서드에 대한 새 호출이 보고되거나, 제너레이터에 대한 새 항목이 보고될 때 Py_tracefunc 함수에 대한 what 매개 변수의 값. 제너레이터 함수에 대한 이터레이터의 생성은 해당 프레임의 파이썬 바이트 코드로의 제어 전송이 없기 때문에 보고되지 않음에 유의하십시오.

int PyTrace_EXCEPTION

예외가 발생했을 때 Py_tracefunc 함수에 대한 what 매개 변수의 값. 콜백 함수는 실행되는 프레임 내에서 바이트 코드가 처리된 후 예외가 설정될 때 what에 대해 이 값으로 호출됩니다. 이것의 효과는 예외 전파로 인해 파이썬 스택이 되감기는 것입니다, 예외가 전파되어 각 프레임으로 반환할 때 콜백이 호출됩니다. 추적 함수만 이러한 이벤트를 수신합니다; 프로파일러에는 필요하지 않습니다.

int PyTrace_LINE

The value passed as the what parameter to a Py_tracefunc function (but not a profiling function) when a line-number event is being reported. It may be disabled for a frame by setting f_trace_lines to 0 on that frame.

int PyTrace_RETURN

호출이 반환되려고 할 때 Py_tracefunc 함수에 대한 what 매개 변수의 값.

int PyTrace_C_CALL

C 함수가 호출되려고 할 때 Py_tracefunc 함수에 대한 what 매개 변수의 값.

int PyTrace_C_EXCEPTION

C 함수에서 예외가 발생했을 때 Py_tracefunc 함수에 대한 what 매개 변수의 값.

int PyTrace_C_RETURN

C 함수가 반환했을 때 Py_tracefunc 함수에 대한 what 매개 변수의 값.

int PyTrace_OPCODE

The value for the what parameter to Py_tracefunc functions (but not profiling functions) when a new opcode is about to be executed. This event is not emitted by default: it must be explicitly requested by setting f_trace_opcodes to 1 on the frame.

void PyEval_SetProfile(Py_tracefunc func, PyObject *obj)

Set the profiler function to func. The obj parameter is passed to the function as its first parameter, and may be any Python object, or NULL. If the profile function needs to maintain state, using a different value for obj for each thread provides a convenient and thread-safe place to store it. The profile function is called for all monitored events except PyTrace_LINE PyTrace_OPCODE and PyTrace_EXCEPTION.

See also the sys.setprofile() function.

호출자는 GIL을 보유하고 있어야 합니다.

void PyEval_SetProfileAllThreads(Py_tracefunc func, PyObject *obj)

Like PyEval_SetProfile() but sets the profile function in all running threads belonging to the current interpreter instead of the setting it only on the current thread.

호출자는 GIL을 보유하고 있어야 합니다.

As PyEval_SetProfile(), this function ignores any exceptions raised while setting the profile functions in all threads.

Added in version 3.12.

void PyEval_SetTrace(Py_tracefunc func, PyObject *obj)

Set the tracing function to func. This is similar to PyEval_SetProfile(), except the tracing function does receive line-number events and per-opcode events, but does not receive any event related to C function objects being called. Any trace function registered using PyEval_SetTrace() will not receive PyTrace_C_CALL, PyTrace_C_EXCEPTION or PyTrace_C_RETURN as a value for the what parameter.

See also the sys.settrace() function.

호출자는 GIL을 보유하고 있어야 합니다.

void PyEval_SetTraceAllThreads(Py_tracefunc func, PyObject *obj)

Like PyEval_SetTrace() but sets the tracing function in all running threads belonging to the current interpreter instead of the setting it only on the current thread.

호출자는 GIL을 보유하고 있어야 합니다.

As PyEval_SetTrace(), this function ignores any exceptions raised while setting the trace functions in all threads.

Added in version 3.12.

Reference tracing

Added in version 3.13.

typedef int (*PyRefTracer)(PyObject*, int event, void *data)

The type of the trace function registered using PyRefTracer_SetTracer(). The first parameter is a Python object that has been just created (when event is set to PyRefTracer_CREATE) or about to be destroyed (when event is set to PyRefTracer_DESTROY). The data argument is the opaque pointer that was provided when PyRefTracer_SetTracer() was called.

Added in version 3.13.

int PyRefTracer_CREATE

The value for the event parameter to PyRefTracer functions when a Python object has been created.

int PyRefTracer_DESTROY

The value for the event parameter to PyRefTracer functions when a Python object has been destroyed.

int PyRefTracer_SetTracer(PyRefTracer tracer, void *data)

Register a reference tracer function. The function will be called when a new Python has been created or when an object is going to be destroyed. If data is provided it must be an opaque pointer that will be provided when the tracer function is called. Return 0 on success. Set an exception and return -1 on error.

Not that tracer functions must not create Python objects inside or otherwise the call will be re-entrant. The tracer also must not clear any existing exception or set an exception. The GIL will be held every time the tracer function is called.

The GIL must be held when calling this function.

Added in version 3.13.

PyRefTracer PyRefTracer_GetTracer(void **data)

Get the registered reference tracer function and the value of the opaque data pointer that was registered when PyRefTracer_SetTracer() was called. If no tracer was registered this function will return NULL and will set the data pointer to NULL.

The GIL must be held when calling this function.

Added in version 3.13.

고급 디버거 지원

이 함수들은 고급 디버깅 도구에서만 사용하기 위한 것입니다.

PyInterpreterState *PyInterpreterState_Head()

인터프리터 상태 객체들의 리스트의 머리에 있는 객체를 반환합니다.

PyInterpreterState *PyInterpreterState_Main()

메인 인터프리터 상태 객체를 반환합니다.

PyInterpreterState *PyInterpreterState_Next(PyInterpreterState *interp)

인터프리터 상태 객체들의 리스트에서 interp 이후의 다음 인터프리터 상태 객체를 반환합니다.

PyThreadState *PyInterpreterState_ThreadHead(PyInterpreterState *interp)

인터프리터 interp와 관련된 스레드 리스트에서 첫 번째 PyThreadState 객체에 대한 포인터를 반환합니다.

PyThreadState *PyThreadState_Next(PyThreadState *tstate)

같은 PyInterpreterState 객체에 속하는 모든 스레드 객체 리스트에서 tstate 이후의 다음 스레드 상태 객체를 반환합니다.

스레드 로컬 저장소 지원

The Python interpreter provides low-level support for thread-local storage (TLS) which wraps the underlying native TLS implementation to support the Python-level thread local storage API (threading.local). The CPython C level APIs are similar to those offered by pthreads and Windows: use a thread key and functions to associate a void* value per thread.

이러한 함수를 호출할 때 GIL을 보유할 필요는 없습니다; 그들은 자체 록을 제공합니다.

Python.h에는 TLS API 선언이 포함되어 있지 않음에 유의하십시오, 스레드 로컬 저장소를 사용하려면 pythread.h를 포함해야 합니다.

참고

None of these API functions handle memory management on behalf of the void* values. You need to allocate and deallocate them yourself. If the void* values happen to be PyObject*, these functions don’t do refcount operations on them either.

스레드별 저장소 (TSS - Thread Specific Storage) API

TSS API is introduced to supersede the use of the existing TLS API within the CPython interpreter. This API uses a new type Py_tss_t instead of int to represent thread keys.

Added in version 3.7.

더 보기

“CPython의 스레드-로컬 저장소를 위한 새로운 C-API” (PEP 539 [https://peps.python.org/pep-0539/])

type Py_tss_t

이 자료 구조는 스레드 키의 상태를 나타내며, 정의는 하부 TLS 구현에 따라 달라질 수 있으며, 키의 초기화 상태를 나타내는 내부 필드가 있습니다. 이 구조체에는 공개 멤버가 없습니다.

Py_LIMITED_API가 정의되지 않을 때, Py_tss_NEEDS_INIT로 이 형의 정적 할당이 허용됩니다.

Py_tss_NEEDS_INIT

이 매크로는 Py_tss_t 변수의 초기화자(initializer)로 확장됩니다. 이 매크로는 Py_LIMITED_API에서 정의되지 않음에 유의하십시오.

동적 할당

Py_LIMITED_API로 빌드된 확장 모듈에 필요한, 빌드 시점에 구현이 불투명해서 형의 정적 할당이 불가능한 Py_tss_t의 동적 할당.

Py_tss_t *PyThread_tss_alloc()

Part of the Stable ABI since version 3.7.

Py_tss_NEEDS_INIT로 초기화된 값과 같은 상태의 값을 반환하거나, 동적 할당 실패 시 NULL을 반환합니다.

void PyThread_tss_free(Py_tss_t *key)

Part of the Stable ABI since version 3.7.

Free the given key allocated by PyThread_tss_alloc(), after first calling PyThread_tss_delete() to ensure any associated thread locals have been unassigned. This is a no-op if the key argument is NULL.

참고

A freed key becomes a dangling pointer. You should reset the key to NULL.

메서드

이 함수들의 매개 변수 key는 NULL이 아니어야 합니다. 또한, 주어진 Py_tss_t가 PyThread_tss_create()로 초기화되지 않았으면, PyThread_tss_set()과 PyThread_tss_get()의 동작은 정의되지 않습니다.

int PyThread_tss_is_created(Py_tss_t *key)

Part of the Stable ABI since version 3.7.

주어진 Py_tss_t가 PyThread_tss_create()로 초기화되었으면 0이 아닌 값을 반환합니다.

int PyThread_tss_create(Py_tss_t *key)

Part of the Stable ABI since version 3.7.

TSS 키 초기화에 성공하면 0 값을 반환합니다. key 인자가 가리키는 값이 Py_tss_NEEDS_INIT로 초기화되지 않으면 동작이 정의되지 않습니다. 이 함수는 같은 키에서 반복적으로 호출될 수 있습니다 – 이미 초기화된 키에 대해 호출하면 아무런 일도 하지 않으며 즉시 성공을 반환합니다.

void PyThread_tss_delete(Py_tss_t *key)

Part of the Stable ABI since version 3.7.

TSS 키를 삭제하여 모든 스레드에서 키와 관련된 값을 잊게 하고, 키의 초기화 상태를 초기화되지 않음으로 변경합니다. 파괴된 키는 PyThread_tss_create()로 다시 초기화할 수 있습니다. 이 함수는 같은 키에서 반복적으로 호출될 수 있습니다 – 이미 파괴된 키에 대해 호출하면 아무런 일도 하지 않습니다.

int PyThread_tss_set(Py_tss_t *key, void *value)

Part of the Stable ABI since version 3.7.

Return a zero value to indicate successfully associating a void* value with a TSS key in the current thread. Each thread has a distinct mapping of the key to a void* value.

void *PyThread_tss_get(Py_tss_t *key)

Part of the Stable ABI since version 3.7.

Return the void* value associated with a TSS key in the current thread. This returns NULL if no value is associated with the key in the current thread.

스레드 로컬 저장소 (TLS) API

버전 3.7부터 폐지됨: 이 API는 스레드별 저장소 (TSS) API로 대체됩니다.

참고

이 버전의 API는 int로 안전하게 캐스트 할 수 없는 방식으로 네이티브 TLS 키가 정의된 플랫폼을 지원하지 않습니다. 이러한 플랫폼에서, PyThread_create_key()는 실패 상태로 즉시 반환되며, 다른 TLS 함수는 이러한 플랫폼에서 모두 아무런 일도 하지 않습니다.

위에서 언급한 호환성 문제로 인해, 이 버전의 API를 새 코드에서 사용해서는 안 됩니다.

int PyThread_create_key()

Part of the Stable ABI.

void PyThread_delete_key(int key)

Part of the Stable ABI.

int PyThread_set_key_value(int key, void *value)

Part of the Stable ABI.

void *PyThread_get_key_value(int key)

Part of the Stable ABI.

void PyThread_delete_key_value(int key)

Part of the Stable ABI.

void PyThread_ReInitTLS()

Part of the Stable ABI.

Synchronization Primitives

The C-API provides a basic mutual exclusion lock.

type PyMutex

A mutual exclusion lock. The PyMutex should be initialized to zero to represent the unlocked state. For example:

PyMutex mutex = {0};

Instances of PyMutex should not be copied or moved. Both the contents and address of a PyMutex are meaningful, and it must remain at a fixed, writable location in memory.

참고

A PyMutex currently occupies one byte, but the size should be considered unstable. The size may change in future Python releases without a deprecation period.

Added in version 3.13.

void PyMutex_Lock(PyMutex *m)

Lock mutex m. If another thread has already locked it, the calling thread will block until the mutex is unlocked. While blocked, the thread will temporarily release the GIL if it is held.

Added in version 3.13.

void PyMutex_Unlock(PyMutex *m)

Unlock mutex m. The mutex must be locked — otherwise, the function will issue a fatal error.

Added in version 3.13.

Python Critical Section API

The critical section API provides a deadlock avoidance layer on top of per-object locks for free-threaded CPython. They are intended to replace reliance on the global interpreter lock, and are no-ops in versions of Python with the global interpreter lock.

Critical sections avoid deadlocks by implicitly suspending active critical sections and releasing the locks during calls to PyEval_SaveThread(). When PyEval_RestoreThread() is called, the most recent critical section is resumed, and its locks reacquired. This means the critical section API provides weaker guarantees than traditional locks – they are useful because their behavior is similar to the GIL.

The functions and structs used by the macros are exposed for cases where C macros are not available. They should only be used as in the given macro expansions. Note that the sizes and contents of the structures may change in future Python versions.

참고

Operations that need to lock two objects at once must use Py_BEGIN_CRITICAL_SECTION2. You cannot use nested critical sections to lock more than one object at once, because the inner critical section may suspend the outer critical sections. This API does not provide a way to lock more than two objects at once.

Example usage:

static PyObject *
set_field(MyObject *self, PyObject *value)
{
   Py_BEGIN_CRITICAL_SECTION(self);
   Py_SETREF(self->field, Py_XNewRef(value));
   Py_END_CRITICAL_SECTION();
   Py_RETURN_NONE;
}

In the above example, Py_SETREF calls Py_DECREF, which can call arbitrary code through an object’s deallocation function. The critical section API avoids potential deadlocks due to reentrancy and lock ordering by allowing the runtime to temporarily suspend the critical section if the code triggered by the finalizer blocks and calls PyEval_SaveThread().

Py_BEGIN_CRITICAL_SECTION(op)

Acquires the per-object lock for the object op and begins a critical section.

In the free-threaded build, this macro expands to:

{
    PyCriticalSection _py_cs;
    PyCriticalSection_Begin(&_py_cs, (PyObject*)(op))

In the default build, this macro expands to {.

Added in version 3.13.

Py_END_CRITICAL_SECTION()

Ends the critical section and releases the per-object lock.

In the free-threaded build, this macro expands to:

    PyCriticalSection_End(&_py_cs);
}

In the default build, this macro expands to }.

Added in version 3.13.

Py_BEGIN_CRITICAL_SECTION2(a, b)

Acquires the per-objects locks for the objects a and b and begins a critical section. The locks are acquired in a consistent order (lowest address first) to avoid lock ordering deadlocks.

In the free-threaded build, this macro expands to:

{
    PyCriticalSection2 _py_cs2;
    PyCriticalSection2_Begin(&_py_cs2, (PyObject*)(a), (PyObject*)(b))

In the default build, this macro expands to {.

Added in version 3.13.

Py_END_CRITICAL_SECTION2()

Ends the critical section and releases the per-object locks.

In the free-threaded build, this macro expands to:

    PyCriticalSection2_End(&_py_cs2);
}

In the default build, this macro expands to }.

Added in version 3.13.

파이썬 초기화 구성

PyConfig C API

Added in version 3.8.

Python can be initialized with Py_InitializeFromConfig() and the PyConfig structure. It can be preinitialized with Py_PreInitialize() and the PyPreConfig structure.

There are two kinds of configuration:

The Python Configuration can be used to build a customized Python which behaves as the regular Python. For example, environment variables and command line arguments are used to configure Python.

The Isolated Configuration can be used to embed Python into an application. It isolates Python from the system. For example, environment variables are ignored, the LC_CTYPE locale is left unchanged and no signal handler is registered.

The Py_RunMain() function can be used to write a customized Python program.

초기화, 파이널리제이션 및 스레드도 참조하십시오.

더 보기

PEP 587 [https://peps.python.org/pep-0587/] “파이썬 초기화 구성”.

Example

항상 격리 모드에서 실행되는 사용자 정의 파이썬의 예:

int main(int argc, char **argv)
{
    PyStatus status;

    PyConfig config;
    PyConfig_InitPythonConfig(&config);
    config.isolated = 1;

    /* Decode command line arguments.
       Implicitly preinitialize Python (in isolated mode). */
    status = PyConfig_SetBytesArgv(&config, argc, argv);
    if (PyStatus_Exception(status)) {
        goto exception;
    }

    status = Py_InitializeFromConfig(&config);
    if (PyStatus_Exception(status)) {
        goto exception;
    }
    PyConfig_Clear(&config);

    return Py_RunMain();

exception:
    PyConfig_Clear(&config);
    if (PyStatus_IsExit(status)) {
        return status.exitcode;
    }
    /* Display the error message and exit the process with
       non-zero exit code */
    Py_ExitStatusException(status);
}

PyWideStringList

type PyWideStringList

wchar_t* 문자열의 리스트.

length가 0이 아니면, items는 NULL이 아니어야 하고 모든 문자열은 NULL이 아니어야 합니다.

메서드:

PyStatus PyWideStringList_Append(PyWideStringList *list, const wchar_t *item)

item을 list에 추가합니다.

이 함수를 호출하려면 파이썬을 사전 초기화해야 합니다.

PyStatus PyWideStringList_Insert(PyWideStringList *list, Py_ssize_t index, const wchar_t *item)

item을 list의 index에 삽입합니다.

index가 list 길이보다 크거나 같으면, item을 list에 추가(append)합니다.

index must be greater than or equal to 0.

이 함수를 호출하려면 파이썬을 사전 초기화해야 합니다.

구조체 필드:

Py_ssize_t length

리스트 길이.

wchar_t **items

리스트 항목들.

PyStatus

type PyStatus

초기화 함수 상태를 저장하는 구조체: 성공, 에러 또는 종료.

에러의 경우, 에러를 만든 C 함수 이름을 저장할 수 있습니다.

구조체 필드:

int exitcode

종료 코드. exit()에 전달된 인자.

const char *err_msg

에러 메시지.

const char *func

에러를 만든 함수의 이름, NULL일 수 있습니다.

상태를 만드는 함수:

PyStatus PyStatus_Ok(void)

성공.

PyStatus PyStatus_Error(const char *err_msg)

메시지가 포함된 초기화 에러.

err_msg must not be NULL.

PyStatus PyStatus_NoMemory(void)

메모리 할당 실패 (메모리 부족).

PyStatus PyStatus_Exit(int exitcode)

지정된 종료 코드로 파이썬을 종료합니다.

상태를 처리하는 함수:

int PyStatus_Exception(PyStatus status)

상태가 에러입니까? 아니면 종료입니까? 참이면, 예외를 처리해야 합니다; 예를 들어 Py_ExitStatusException() 을 호출하여.

int PyStatus_IsError(PyStatus status)

결과가 에러입니까?

int PyStatus_IsExit(PyStatus status)

결과가 종료입니까?

void Py_ExitStatusException(PyStatus status)

status가 종료이면 exit(exitcode)를 호출합니다. status가 에러이면 에러 메시지를 인쇄하고 0이 아닌 종료 코드로 종료합니다. PyStatus_Exception(status)가 0이 아닐 때만 호출해야 합니다.

참고

내부적으로, 파이썬은 PyStatus.func를 설정하는 데는 매크로를 사용하는 반면, func가 NULL로 설정된 상태를 만드는 데는 함수를 사용합니다.

예:

PyStatus alloc(void **ptr, size_t size)
{
    *ptr = PyMem_RawMalloc(size);
    if (*ptr == NULL) {
        return PyStatus_NoMemory();
    }
    return PyStatus_Ok();
}

int main(int argc, char **argv)
{
    void *ptr;
    PyStatus status = alloc(&ptr, 16);
    if (PyStatus_Exception(status)) {
        Py_ExitStatusException(status);
    }
    PyMem_Free(ptr);
    return 0;
}

PyPreConfig

type PyPreConfig

Structure used to preinitialize Python.

사전 구성을 초기화하는 함수:

void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)

파이썬 구성으로 사전 구성을 초기화합니다.

void PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)

격리된 구성으로 사전 구성을 초기화합니다.

구조체 필드:

int allocator

Name of the Python memory allocators:

PYMEM_ALLOCATOR_NOT_SET (0): don’t change memory allocators (use defaults).

PYMEM_ALLOCATOR_DEFAULT (1): default memory allocators.

PYMEM_ALLOCATOR_DEBUG (2): default memory allocators with debug hooks.

PYMEM_ALLOCATOR_MALLOC (3): use malloc() of the C library.

PYMEM_ALLOCATOR_MALLOC_DEBUG (4): force usage of malloc() with debug hooks.

PYMEM_ALLOCATOR_PYMALLOC (5): Python pymalloc memory allocator.

PYMEM_ALLOCATOR_PYMALLOC_DEBUG (6): Python pymalloc memory allocator with debug hooks.

PYMEM_ALLOCATOR_MIMALLOC (6): use mimalloc, a fast malloc replacement.

PYMEM_ALLOCATOR_MIMALLOC_DEBUG (7): use mimalloc, a fast malloc replacement with debug hooks.

PYMEM_ALLOCATOR_PYMALLOC and PYMEM_ALLOCATOR_PYMALLOC_DEBUG are not supported if Python is configured using --without-pymalloc.

PYMEM_ALLOCATOR_MIMALLOC and PYMEM_ALLOCATOR_MIMALLOC_DEBUG are not supported if Python is configured using --without-mimalloc or if the underlying atomic support isn’t available.

메모리 관리를 참조하십시오.

Default: PYMEM_ALLOCATOR_NOT_SET.

int configure_locale

Set the LC_CTYPE locale to the user preferred locale.

If equals to 0, set coerce_c_locale and coerce_c_locale_warn members to 0.

See the locale encoding.

Default: 1 in Python config, 0 in isolated config.

int coerce_c_locale

If equals to 2, coerce the C locale.

If equals to 1, read the LC_CTYPE locale to decide if it should be coerced.

See the locale encoding.

Default: -1 in Python config, 0 in isolated config.

int coerce_c_locale_warn

0이 아니면, C 로케일이 강제될 때 경고가 발생합니다.

Default: -1 in Python config, 0 in isolated config.

int dev_mode

Python Development Mode: see PyConfig.dev_mode.

Default: -1 in Python mode, 0 in isolated mode.

int isolated

Isolated mode: see PyConfig.isolated.

Default: 0 in Python mode, 1 in isolated mode.

int legacy_windows_fs_encoding

If non-zero:

Set PyPreConfig.utf8_mode to 0,

Set PyConfig.filesystem_encoding to "mbcs",

Set PyConfig.filesystem_errors to "replace".

Initialized from the PYTHONLEGACYWINDOWSFSENCODING environment variable value.

윈도우에서만 사용 가능합니다. #ifdef MS_WINDOWS 매크로는 윈도우 특정 코드에 사용할 수 있습니다.

Default: 0.

int parse_argv

0이 아니면, Py_PreInitializeFromArgs()와 Py_PreInitializeFromBytesArgs()는 일반 파이썬이 명령 줄 인자를 구문 분석하는 것과 같은 방식으로 argv 인자를 구문 분석합니다. 명령 줄 인자를 참조하십시오.

Default: 1 in Python config, 0 in isolated config.

int use_environment

Use environment variables? See PyConfig.use_environment.

Default: 1 in Python config and 0 in isolated config.

int utf8_mode

If non-zero, enable the Python UTF-8 Mode.

Set to 0 or 1 by the -X utf8 command line option and the PYTHONUTF8 environment variable.

Also set to 1 if the LC_CTYPE locale is C or POSIX.

Default: -1 in Python config and 0 in isolated config.

Preinitialize Python with PyPreConfig

The preinitialization of Python:

Set the Python memory allocators (PyPreConfig.allocator)

Configure the LC_CTYPE locale (locale encoding)

Set the Python UTF-8 Mode (PyPreConfig.utf8_mode)

The current preconfiguration (PyPreConfig type) is stored in _PyRuntime.preconfig.

파이썬을 사전 초기화하는 함수:

PyStatus Py_PreInitialize(const PyPreConfig *preconfig)

preconfig 사전 구성에서 파이썬을 사전 초기화합니다.

preconfig must not be NULL.

PyStatus Py_PreInitializeFromBytesArgs(const PyPreConfig *preconfig, int argc, char *const *argv)

preconfig 사전 구성에서 파이썬을 사전 초기화합니다.

Parse argv command line arguments (bytes strings) if parse_argv of preconfig is non-zero.

preconfig must not be NULL.

PyStatus Py_PreInitializeFromArgs(const PyPreConfig *preconfig, int argc, wchar_t *const *argv)

preconfig 사전 구성에서 파이썬을 사전 초기화합니다.

Parse argv command line arguments (wide strings) if parse_argv of preconfig is non-zero.

preconfig must not be NULL.

호출자는 PyStatus_Exception()과 Py_ExitStatusException() 을 사용하여 예외(에러나 종료)를 처리해야 합니다.

For Python Configuration (PyPreConfig_InitPythonConfig()), if Python is initialized with command line arguments, the command line arguments must also be passed to preinitialize Python, since they have an effect on the pre-configuration like encodings. For example, the -X utf8 command line option enables the Python UTF-8 Mode.

PyMem_SetAllocator()는 Py_PreInitialize() 이후에 Py_InitializeFromConfig() 이전에 호출하여 사용자 정의 메모리 할당자를 설치할 수 있습니다. PyPreConfig.allocator가 PYMEM_ALLOCATOR_NOT_SET으로 설정되면 Py_PreInitialize() 전에 호출할 수 있습니다.

Python memory allocation functions like PyMem_RawMalloc() must not be used before the Python preinitialization, whereas calling directly malloc() and free() is always safe. Py_DecodeLocale() must not be called before the Python preinitialization.

Example using the preinitialization to enable the Python UTF-8 Mode:

PyStatus status;
PyPreConfig preconfig;
PyPreConfig_InitPythonConfig(&preconfig);

preconfig.utf8_mode = 1;

status = Py_PreInitialize(&preconfig);
if (PyStatus_Exception(status)) {
    Py_ExitStatusException(status);
}

/* at this point, Python speaks UTF-8 */

Py_Initialize();
/* ... use Python API here ... */
Py_Finalize();

PyConfig

type PyConfig

파이썬을 구성하기 위한 대부분의 파라미터를 포함하는 구조체.

When done, the PyConfig_Clear() function must be used to release the configuration memory.

구조체 메서드:

void PyConfig_InitPythonConfig(PyConfig *config)

Initialize configuration with the Python Configuration.

void PyConfig_InitIsolatedConfig(PyConfig *config)

Initialize configuration with the Isolated Configuration.

PyStatus PyConfig_SetString(PyConfig *config, wchar_t *const *config_str, const wchar_t *str)

와이드 문자열 str을 *config_str로 복사합니다.

Preinitialize Python if needed.

PyStatus PyConfig_SetBytesString(PyConfig *config, wchar_t *const *config_str, const char *str)

Decode str using Py_DecodeLocale() and set the result into *config_str.

Preinitialize Python if needed.

PyStatus PyConfig_SetArgv(PyConfig *config, int argc, wchar_t *const *argv)

Set command line arguments (argv member of config) from the argv list of wide character strings.

Preinitialize Python if needed.

PyStatus PyConfig_SetBytesArgv(PyConfig *config, int argc, char *const *argv)

Set command line arguments (argv member of config) from the argv list of bytes strings. Decode bytes using Py_DecodeLocale().

Preinitialize Python if needed.

PyStatus PyConfig_SetWideStringList(PyConfig *config, PyWideStringList *list, Py_ssize_t length, wchar_t **items)

와이드 문자열 리스트 list를 length와 items로 설정합니다.

Preinitialize Python if needed.

PyStatus PyConfig_Read(PyConfig *config)

모든 파이썬 구성을 읽습니다.

이미 초기화된 필드는 변경되지 않습니다.

Fields for path configuration are no longer calculated or modified when calling this function, as of Python 3.11.

The PyConfig_Read() function only parses PyConfig.argv arguments once: PyConfig.parse_argv is set to 2 after arguments are parsed. Since Python arguments are stripped from PyConfig.argv, parsing arguments twice would parse the application options as Python options.

Preinitialize Python if needed.

버전 3.10에서 변경: The PyConfig.argv arguments are now only parsed once, PyConfig.parse_argv is set to 2 after arguments are parsed, and arguments are only parsed if PyConfig.parse_argv equals 1.

버전 3.11에서 변경: PyConfig_Read() no longer calculates all paths, and so fields listed under Python Path Configuration may no longer be updated until Py_InitializeFromConfig() is called.

void PyConfig_Clear(PyConfig *config)

구성 메모리를 해제합니다.

Most PyConfig methods preinitialize Python if needed. In that case, the Python preinitialization configuration (PyPreConfig) in based on the PyConfig. If configuration fields which are in common with PyPreConfig are tuned, they must be set before calling a PyConfig method:

PyConfig.dev_mode

PyConfig.isolated

PyConfig.parse_argv

PyConfig.use_environment

Moreover, if PyConfig_SetArgv() or PyConfig_SetBytesArgv() is used, this method must be called before other methods, since the preinitialization configuration depends on command line arguments (if parse_argv is non-zero).

이 메서드의 호출자는 PyStatus_Exception()과 Py_ExitStatusException() 을 사용하여 예외(에러나 종료)를 처리해야 합니다.

구조체 필드:

PyWideStringList argv

Set sys.argv command line arguments based on argv. These parameters are similar to those passed to the program’s main() function with the difference that the first entry should refer to the script file to be executed rather than the executable hosting the Python interpreter. If there isn’t a script that will be run, the first entry in argv can be an empty string.

Set parse_argv to 1 to parse argv the same way the regular Python parses Python command line arguments and then to strip Python arguments from argv.

If argv is empty, an empty string is added to ensure that sys.argv always exists and is never empty.

Default: NULL.

See also the orig_argv member.

int safe_path

If equals to zero, Py_RunMain() prepends a potentially unsafe path to sys.path at startup:

If argv[0] is equal to L"-m" (python -m module), prepend the current working directory.

If running a script (python script.py), prepend the script’s directory. If it’s a symbolic link, resolve symbolic links.

Otherwise (python -c code and python), prepend an empty string, which means the current working directory.

Set to 1 by the -P command line option and the PYTHONSAFEPATH environment variable.

Default: 0 in Python config, 1 in isolated config.

Added in version 3.11.

wchar_t *base_exec_prefix

sys.base_exec_prefix.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.exec_prefix.

wchar_t *base_executable

Python base executable: sys._base_executable.

Set by the __PYVENV_LAUNCHER__ environment variable.

Set from PyConfig.executable if NULL.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.executable.

wchar_t *base_prefix

sys.base_prefix.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.prefix.

int buffered_stdio

If equals to 0 and configure_c_stdio is non-zero, disable buffering on the C streams stdout and stderr.

Set to 0 by the -u command line option and the PYTHONUNBUFFERED environment variable.

stdin은 항상 버퍼링 모드로 열립니다.

Default: 1.

int bytes_warning

If equals to 1, issue a warning when comparing bytes or bytearray with str, or comparing bytes with int.

If equal or greater to 2, raise a BytesWarning exception in these cases.

Incremented by the -b command line option.

Default: 0.

int warn_default_encoding

If non-zero, emit a EncodingWarning warning when io.TextIOWrapper uses its default encoding. See Opt-in EncodingWarning for details.

Default: 0.

Added in version 3.10.

int code_debug_ranges

If equals to 0, disables the inclusion of the end line and column mappings in code objects. Also disables traceback printing carets to specific error locations.

Set to 0 by the PYTHONNODEBUGRANGES environment variable and by the -X no_debug_ranges command line option.

Default: 1.

Added in version 3.11.

wchar_t *check_hash_pycs_mode

Control the validation behavior of hash-based .pyc files: value of the --check-hash-based-pycs command line option.

Valid values:

L"always": Hash the source file for invalidation regardless of value of the ‘check_source’ flag.

L"never": Assume that hash-based pycs always are valid.

L"default": The ‘check_source’ flag in hash-based pycs determines invalidation.

Default: L"default".

See also PEP 552 [https://peps.python.org/pep-0552/] “Deterministic pycs”.

int configure_c_stdio

If non-zero, configure C standard streams:

On Windows, set the binary mode (O_BINARY) on stdin, stdout and stderr.

If buffered_stdio equals zero, disable buffering of stdin, stdout and stderr streams.

If interactive is non-zero, enable stream buffering on stdin and stdout (only stdout on Windows).

Default: 1 in Python config, 0 in isolated config.

int dev_mode

0이 아니면, 파이썬 개발 모드를 활성화합니다.

Set to 1 by the -X dev option and the PYTHONDEVMODE environment variable.

Default: -1 in Python mode, 0 in isolated mode.

int dump_refs

Dump Python references?

0이 아니면, 종료 시 여전히 활성 상태인 모든 객체를 덤프합니다.

Set to 1 by the PYTHONDUMPREFS environment variable.

Needs a special build of Python with the Py_TRACE_REFS macro defined: see the configure --with-trace-refs option.

Default: 0.

wchar_t *exec_prefix

The site-specific directory prefix where the platform-dependent Python files are installed: sys.exec_prefix.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.base_exec_prefix.

wchar_t *executable

The absolute path of the executable binary for the Python interpreter: sys.executable.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.base_executable.

int faulthandler

Enable faulthandler?

0이 아니면, 시작 시 faulthandler.enable()을 호출합니다.

Set to 1 by -X faulthandler and the PYTHONFAULTHANDLER environment variable.

Default: -1 in Python mode, 0 in isolated mode.

wchar_t *filesystem_encoding

Filesystem encoding: sys.getfilesystemencoding().

On macOS, Android and VxWorks: use "utf-8" by default.

On Windows: use "utf-8" by default, or "mbcs" if legacy_windows_fs_encoding of PyPreConfig is non-zero.

Default encoding on other platforms:

"utf-8" if PyPreConfig.utf8_mode is non-zero.

"ascii" if Python detects that nl_langinfo(CODESET) announces the ASCII encoding, whereas the mbstowcs() function decodes from a different encoding (usually Latin1).

"utf-8" if nl_langinfo(CODESET) returns an empty string.

Otherwise, use the locale encoding: nl_langinfo(CODESET) result.

At Python startup, the encoding name is normalized to the Python codec name. For example, "ANSI_X3.4-1968" is replaced with "ascii".

See also the filesystem_errors member.

wchar_t *filesystem_errors

Filesystem error handler: sys.getfilesystemencodeerrors().

On Windows: use "surrogatepass" by default, or "replace" if legacy_windows_fs_encoding of PyPreConfig is non-zero.

On other platforms: use "surrogateescape" by default.

Supported error handlers:

"strict"

"surrogateescape"

"surrogatepass" (only supported with the UTF-8 encoding)

See also the filesystem_encoding member.

unsigned long hash_seed

int use_hash_seed

무작위 해시 함수 시드.

If use_hash_seed is zero, a seed is chosen randomly at Python startup, and hash_seed is ignored.

Set by the PYTHONHASHSEED environment variable.

Default use_hash_seed value: -1 in Python mode, 0 in isolated mode.

wchar_t *home

Set the default Python “home” directory, that is, the location of the standard Python libraries (see PYTHONHOME).

Set by the PYTHONHOME environment variable.

Default: NULL.

Part of the Python Path Configuration input.

int import_time

0이 아니면, 임포트 시간을 프로파일 합니다.

Set the 1 by the -X importtime option and the PYTHONPROFILEIMPORTTIME environment variable.

Default: 0.

int inspect

스크립트나 명령을 실행한 후 대화식 모드로 들어갑니다.

If greater than 0, enable inspect: when a script is passed as first argument or the -c option is used, enter interactive mode after executing the script or the command, even when sys.stdin does not appear to be a terminal.

Incremented by the -i command line option. Set to 1 if the PYTHONINSPECT environment variable is non-empty.

Default: 0.

int install_signal_handlers

Install Python signal handlers?

Default: 1 in Python mode, 0 in isolated mode.

int interactive

If greater than 0, enable the interactive mode (REPL).

Incremented by the -i command line option.

Default: 0.

int int_max_str_digits

Configures the integer string conversion length limitation. An initial value of -1 means the value will be taken from the command line or environment or otherwise default to 4300 (sys.int_info.default_max_str_digits). A value of 0 disables the limitation. Values greater than zero but less than 640 (sys.int_info.str_digits_check_threshold) are unsupported and will produce an error.

Configured by the -X int_max_str_digits command line flag or the PYTHONINTMAXSTRDIGITS environment variable.

Default: -1 in Python mode. 4300 (sys.int_info.default_max_str_digits) in isolated mode.

Added in version 3.12.

int cpu_count

If the value of cpu_count is not -1 then it will override the return values of os.cpu_count(), os.process_cpu_count(), and multiprocessing.cpu_count().

Configured by the -X cpu_count=n|default command line flag or the PYTHON_CPU_COUNT environment variable.

Default: -1.

Added in version 3.13.

int isolated

If greater than 0, enable isolated mode:

Set safe_path to 1: don’t prepend a potentially unsafe path to sys.path at Python startup, such as the current directory, the script’s directory or an empty string.

Set use_environment to 0: ignore PYTHON environment variables.

Set user_site_directory to 0: don’t add the user site directory to sys.path.

파이썬 REPL은 대화식 프롬프트에서 readline을 임포트 하지도 기본 readline 구성을 활성화하지도 않습니다.

Set to 1 by the -I command line option.

Default: 0 in Python mode, 1 in isolated mode.

See also the Isolated Configuration and PyPreConfig.isolated.

int legacy_windows_stdio

If non-zero, use io.FileIO instead of io._WindowsConsoleIO for sys.stdin, sys.stdout and sys.stderr.

Set to 1 if the PYTHONLEGACYWINDOWSSTDIO environment variable is set to a non-empty string.

윈도우에서만 사용 가능합니다. #ifdef MS_WINDOWS 매크로는 윈도우 특정 코드에 사용할 수 있습니다.

Default: 0.

See also the PEP 528 [https://peps.python.org/pep-0528/] (Change Windows console encoding to UTF-8).

int malloc_stats

0이 아니면, 종료 시 파이썬 pymalloc 메모리 할당자에 대한 통계를 덤프합니다.

Set to 1 by the PYTHONMALLOCSTATS environment variable.

The option is ignored if Python is configured using the --without-pymalloc option.

Default: 0.

wchar_t *platlibdir

Platform library directory name: sys.platlibdir.

Set by the PYTHONPLATLIBDIR environment variable.

Default: value of the PLATLIBDIR macro which is set by the configure --with-platlibdir option (default: "lib", or "DLLs" on Windows).

Part of the Python Path Configuration input.

Added in version 3.9.

버전 3.11에서 변경: This macro is now used on Windows to locate the standard library extension modules, typically under DLLs. However, for compatibility, note that this value is ignored for any non-standard layouts, including in-tree builds and virtual environments.

wchar_t *pythonpath_env

Module search paths (sys.path) as a string separated by DELIM (os.pathsep).

Set by the PYTHONPATH environment variable.

Default: NULL.

Part of the Python Path Configuration input.

PyWideStringList module_search_paths

int module_search_paths_set

Module search paths: sys.path.

If module_search_paths_set is equal to 0, Py_InitializeFromConfig() will replace module_search_paths and sets module_search_paths_set to 1.

Default: empty list (module_search_paths) and 0 (module_search_paths_set).

Part of the Python Path Configuration output.

int optimization_level

컴파일 최적화 수준:

0: Peephole optimizer, set __debug__ to True.

1: Level 0, remove assertions, set __debug__ to False.

2: Level 1, strip docstrings.

Incremented by the -O command line option. Set to the PYTHONOPTIMIZE environment variable value.

Default: 0.

PyWideStringList orig_argv

The list of the original command line arguments passed to the Python executable: sys.orig_argv.

If orig_argv list is empty and argv is not a list only containing an empty string, PyConfig_Read() copies argv into orig_argv before modifying argv (if parse_argv is non-zero).

See also the argv member and the Py_GetArgcArgv() function.

Default: empty list.

Added in version 3.10.

int parse_argv

Parse command line arguments?

If equals to 1, parse argv the same way the regular Python parses command line arguments, and strip Python arguments from argv.

The PyConfig_Read() function only parses PyConfig.argv arguments once: PyConfig.parse_argv is set to 2 after arguments are parsed. Since Python arguments are stripped from PyConfig.argv, parsing arguments twice would parse the application options as Python options.

Default: 1 in Python mode, 0 in isolated mode.

버전 3.10에서 변경: The PyConfig.argv arguments are now only parsed if PyConfig.parse_argv equals to 1.

int parser_debug

Parser debug mode. If greater than 0, turn on parser debugging output (for expert only, depending on compilation options).

Incremented by the -d command line option. Set to the PYTHONDEBUG environment variable value.

Needs a debug build of Python (the Py_DEBUG macro must be defined).

Default: 0.

int pathconfig_warnings

If non-zero, calculation of path configuration is allowed to log warnings into stderr. If equals to 0, suppress these warnings.

Default: 1 in Python mode, 0 in isolated mode.

Part of the Python Path Configuration input.

버전 3.11에서 변경: Now also applies on Windows.

wchar_t *prefix

The site-specific directory prefix where the platform independent Python files are installed: sys.prefix.

Default: NULL.

Part of the Python Path Configuration output.

See also PyConfig.base_prefix.

wchar_t *program_name

Program name used to initialize executable and in early error messages during Python initialization.

On macOS, use PYTHONEXECUTABLE environment variable if set.

If the WITH_NEXT_FRAMEWORK macro is defined, use __PYVENV_LAUNCHER__ environment variable if set.

Use argv[0] of argv if available and non-empty.

Otherwise, use L"python" on Windows, or L"python3" on other platforms.

Default: NULL.

Part of the Python Path Configuration input.

wchar_t *pycache_prefix

Directory where cached .pyc files are written: sys.pycache_prefix.

Set by the -X pycache_prefix=PATH command line option and the PYTHONPYCACHEPREFIX environment variable. The command-line option takes precedence.

NULL이면, sys.pycache_prefix는 None으로 설정됩니다.

Default: NULL.

int quiet

Quiet mode. If greater than 0, don’t display the copyright and version at Python startup in interactive mode.

Incremented by the -q command line option.

Default: 0.

wchar_t *run_command

Value of the -c command line option.

Used by Py_RunMain().

Default: NULL.

wchar_t *run_filename

Filename passed on the command line: trailing command line argument without -c or -m. It is used by the Py_RunMain() function.

For example, it is set to script.py by the python3 script.py arg command line.

See also the PyConfig.skip_source_first_line option.

Default: NULL.

wchar_t *run_module

Value of the -m command line option.

Used by Py_RunMain().

Default: NULL.

wchar_t *run_presite

package.module path to module that should be imported before site.py is run.

Set by the -X presite=package.module command-line option and the PYTHON_PRESITE environment variable. The command-line option takes precedence.

Needs a debug build of Python (the Py_DEBUG macro must be defined).

Default: NULL.

int show_ref_count

Show total reference count at exit (excluding immortal objects)?

Set to 1 by -X showrefcount command line option.

Needs a debug build of Python (the Py_REF_DEBUG macro must be defined).

Default: 0.

int site_import

시작할 때 site 모듈을 임포트 합니까?

If equal to zero, disable the import of the module site and the site-dependent manipulations of sys.path that it entails.

Also disable these manipulations if the site module is explicitly imported later (call site.main() if you want them to be triggered).

Set to 0 by the -S command line option.

sys.flags.no_site is set to the inverted value of site_import.

Default: 1.

int skip_source_first_line

If non-zero, skip the first line of the PyConfig.run_filename source.

It allows the usage of non-Unix forms of #!cmd. This is intended for a DOS specific hack only.

Set to 1 by the -x command line option.

Default: 0.

wchar_t *stdio_encoding

wchar_t *stdio_errors

Encoding and encoding errors of sys.stdin, sys.stdout and sys.stderr (but sys.stderr always uses "backslashreplace" error handler).

Use the PYTHONIOENCODING environment variable if it is non-empty.

Default encoding:

"UTF-8" if PyPreConfig.utf8_mode is non-zero.

Otherwise, use the locale encoding.

Default error handler:

On Windows: use "surrogateescape".

"surrogateescape" if PyPreConfig.utf8_mode is non-zero, or if the LC_CTYPE locale is “C” or “POSIX”.

"strict" otherwise.

See also PyConfig.legacy_windows_stdio.

int tracemalloc

Enable tracemalloc?

0이 아니면, 시작 시 tracemalloc.start()를 호출합니다.

Set by -X tracemalloc=N command line option and by the PYTHONTRACEMALLOC environment variable.

Default: -1 in Python mode, 0 in isolated mode.

int perf_profiling

Enable the Linux perf profiler support?

If equals to 1, enable support for the Linux perf profiler.

If equals to 2, enable support for the Linux perf profiler with DWARF JIT support.

Set to 1 by -X perf command-line option and the PYTHONPERFSUPPORT environment variable.

Set to 2 by the -X perf_jit command-line option and the PYTHON_PERF_JIT_SUPPORT environment variable.

Default: -1.

더 보기

See Python support for the Linux perf profiler for more information.

Added in version 3.12.

int use_environment

Use environment variables?

If equals to zero, ignore the environment variables.

Set to 0 by the -E environment variable.

Default: 1 in Python config and 0 in isolated config.

int user_site_directory

If non-zero, add the user site directory to sys.path.

Set to 0 by the -s and -I command line options.

Set to 0 by the PYTHONNOUSERSITE environment variable.

Default: 1 in Python mode, 0 in isolated mode.

int verbose

Verbose mode. If greater than 0, print a message each time a module is imported, showing the place (filename or built-in module) from which it is loaded.

If greater than or equal to 2, print a message for each file that is checked for when searching for a module. Also provides information on module cleanup at exit.

Incremented by the -v command line option.

Set by the PYTHONVERBOSE environment variable value.

Default: 0.

PyWideStringList warnoptions

Options of the warnings module to build warnings filters, lowest to highest priority: sys.warnoptions.

warnings 모듈은 sys.warnoptions를 역순으로 추가합니다: 마지막 PyConfig.warnoptions 항목은 가장 먼저 검사되는 warnings.filters의 첫 번째 항목이 됩니다 (가장 높은 우선순위).

The -W command line options adds its value to warnoptions, it can be used multiple times.

The PYTHONWARNINGS environment variable can also be used to add warning options. Multiple options can be specified, separated by commas (,).

Default: empty list.

int write_bytecode

If equal to 0, Python won’t try to write .pyc files on the import of source modules.

Set to 0 by the -B command line option and the PYTHONDONTWRITEBYTECODE environment variable.

sys.dont_write_bytecode는 write_bytecode의 반전된 값으로 초기화됩니다.

Default: 1.

PyWideStringList xoptions

Values of the -X command line options: sys._xoptions.

Default: empty list.

If parse_argv is non-zero, argv arguments are parsed the same way the regular Python parses command line arguments, and Python arguments are stripped from argv.

The xoptions options are parsed to set other options: see the -X command line option.

버전 3.9에서 변경: show_alloc_count 필드가 제거되었습니다.

PyConfig를 사용한 초기화

Initializing the interpreter from a populated configuration struct is handled by calling Py_InitializeFromConfig().

호출자는 PyStatus_Exception()과 Py_ExitStatusException() 을 사용하여 예외(에러나 종료)를 처리해야 합니다.

If PyImport_FrozenModules(), PyImport_AppendInittab() or PyImport_ExtendInittab() are used, they must be set or called after Python preinitialization and before the Python initialization. If Python is initialized multiple times, PyImport_AppendInittab() or PyImport_ExtendInittab() must be called before each Python initialization.

The current configuration (PyConfig type) is stored in PyInterpreterState.config.

프로그램 이름을 설정하는 예:

void init_python(void)
{
    PyStatus status;

    PyConfig config;
    PyConfig_InitPythonConfig(&config);

    /* Set the program name. Implicitly preinitialize Python. */
    status = PyConfig_SetString(&config, &config.program_name,
                                L"/path/to/my_program");
    if (PyStatus_Exception(status)) {
        goto exception;
    }

    status = Py_InitializeFromConfig(&config);
    if (PyStatus_Exception(status)) {
        goto exception;
    }
    PyConfig_Clear(&config);
    return;

exception:
    PyConfig_Clear(&config);
    Py_ExitStatusException(status);
}

More complete example modifying the default configuration, read the configuration, and then override some parameters. Note that since 3.11, many parameters are not calculated until initialization, and so values cannot be read from the configuration structure. Any values set before initialize is called will be left unchanged by initialization:

PyStatus init_python(const char *program_name)
{
    PyStatus status;

    PyConfig config;
    PyConfig_InitPythonConfig(&config);

    /* Set the program name before reading the configuration
       (decode byte string from the locale encoding).

       Implicitly preinitialize Python. */
    status = PyConfig_SetBytesString(&config, &config.program_name,
                                     program_name);
    if (PyStatus_Exception(status)) {
        goto done;
    }

    /* Read all configuration at once */
    status = PyConfig_Read(&config);
    if (PyStatus_Exception(status)) {
        goto done;
    }

    /* Specify sys.path explicitly */
    /* If you want to modify the default set of paths, finish
       initialization first and then use PySys_GetObject("path") */
    config.module_search_paths_set = 1;
    status = PyWideStringList_Append(&config.module_search_paths,
                                     L"/path/to/stdlib");
    if (PyStatus_Exception(status)) {
        goto done;
    }
    status = PyWideStringList_Append(&config.module_search_paths,
                                     L"/path/to/more/modules");
    if (PyStatus_Exception(status)) {
        goto done;
    }

    /* Override executable computed by PyConfig_Read() */
    status = PyConfig_SetString(&config, &config.executable,
                                L"/path/to/my_executable");
    if (PyStatus_Exception(status)) {
        goto done;
    }

    status = Py_InitializeFromConfig(&config);

done:
    PyConfig_Clear(&config);
    return status;
}

격리된 구성

PyPreConfig_InitIsolatedConfig()와 PyConfig_InitIsolatedConfig() 함수는 시스템에서 파이썬을 격리하는 구성을 만듭니다. 예를 들어, 파이썬을 응용 프로그램에 내장하기 위해.

This configuration ignores global configuration variables, environment variables, command line arguments (PyConfig.argv is not parsed) and user site directory. The C standard streams (ex: stdout) and the LC_CTYPE locale are left unchanged. Signal handlers are not installed.

Configuration files are still used with this configuration to determine paths that are unspecified. Ensure PyConfig.home is specified to avoid computing the default path configuration.

파이썬 구성

PyPreConfig_InitPythonConfig()와 PyConfig_InitPythonConfig() 함수는 일반 파이썬처럼 동작하는 사용자 정의된 파이썬을 빌드하기 위한 구성을 만듭니다.

환경 변수와 명령 줄 인자는 파이썬을 구성하는 데 사용되는 반면, 전역 구성 변수는 무시됩니다.

This function enables C locale coercion (PEP 538 [https://peps.python.org/pep-0538/]) and Python UTF-8 Mode (PEP 540 [https://peps.python.org/pep-0540/]) depending on the LC_CTYPE locale, PYTHONUTF8 and PYTHONCOERCECLOCALE environment variables.

Python Path Configuration

PyConfig에는 경로 구성을 위한 여러 필드가 포함되어 있습니다:

경로 구성 입력:

PyConfig.home

PyConfig.platlibdir

PyConfig.pathconfig_warnings

PyConfig.program_name

PyConfig.pythonpath_env

현재 작업 디렉터리: 절대 경로를 얻기 위해

(PyConfig.program_name에서) 프로그램 전체 경로를 얻기 위한 PATH 환경 변수

__PYVENV_LAUNCHER__ 환경 변수

(윈도우 전용) HKEY_CURRENT_USER와 HKEY_LOCAL_MACHINE의 “SoftwarePythonPythonCoreX.YPythonPath” 아래에 있는 레지스트리의 응용 프로그램 경로 (여기서 X.Y는 파이썬 버전입니다).

경로 구성 출력 필드:

PyConfig.base_exec_prefix

PyConfig.base_executable

PyConfig.base_prefix

PyConfig.exec_prefix

PyConfig.executable

PyConfig.module_search_paths_set, PyConfig.module_search_paths

PyConfig.prefix

If at least one “output field” is not set, Python calculates the path configuration to fill unset fields. If module_search_paths_set is equal to 0, module_search_paths is overridden and module_search_paths_set is set to 1.

It is possible to completely ignore the function calculating the default path configuration by setting explicitly all path configuration output fields listed above. A string is considered as set even if it is non-empty. module_search_paths is considered as set if module_search_paths_set is set to 1. In this case, module_search_paths will be used without modification.

Set pathconfig_warnings to 0 to suppress warnings when calculating the path configuration (Unix only, Windows does not log any warning).

base_prefix나 base_exec_prefix 필드가 설정되지 않으면, 각각 prefix와 exec_prefix의 값을 상속합니다.

Py_RunMain()과 Py_Main()은 sys.path를 수정합니다:

run_filename이 설정되고 __main__.py 스크립트를 포함하는 디렉터리이면, run_filename을 sys.path 앞에 추가합니다.

isolated가 0이면:

run_module이 설정되면, 현재 디렉터리를 sys.path 앞에 추가합니다. 현재 디렉터리를 읽을 수 없으면 아무것도 하지 않습니다.

run_filename이 설정되면, 파일명의 디렉터리를 sys.path 앞에 추가합니다.

그렇지 않으면, 빈 문자열을 sys.path 앞에 추가합니다.

site_import가 0이 아니면, site 모듈이 sys.path를 수정할 수 있습니다. user_site_directory가 0이 아니고 사용자의 site-package 디렉터리가 존재하면, site 모듈은 사용자의 site-package 디렉터리를 sys.path에 추가합니다.

다음과 같은 구성 파일이 경로 구성에 사용됩니다:

pyvenv.cfg

._pth file (ex: python._pth)

pybuilddir.txt (유닉스 전용)

If a ._pth file is present:

Set isolated to 1.

Set use_environment to 0.

Set site_import to 0.

Set safe_path to 1.

If home is not set and a pyvenv.cfg file is present in the same directory as executable, or its parent, prefix and exec_prefix are set that location. When this happens, base_prefix and base_exec_prefix still keep their value, pointing to the base installation. See Virtual Environments for more information.

The __PYVENV_LAUNCHER__ environment variable is used to set PyConfig.base_executable.

버전 3.14에서 변경: prefix, and exec_prefix, are now set to the pyvenv.cfg directory. This was previously done by site, therefore affected by -S.

PyInitConfig C API

C API to configure the Python initialization (PEP 741 [https://peps.python.org/pep-0741/]).

Added in version 3.14.

Create Config

struct PyInitConfig

Opaque structure to configure the Python initialization.

PyInitConfig *PyInitConfig_Create(void)

Create a new initialization configuration using Isolated Configuration default values.

It must be freed by PyInitConfig_Free().

Return NULL on memory allocation failure.

void PyInitConfig_Free(PyInitConfig *config)

Free memory of the initialization configuration config.

If config is NULL, no operation is performed.

Error Handling

int PyInitConfig_GetError(PyInitConfig *config, const char **err_msg)

Get the config error message.

Set *err_msg and return 1 if an error is set.

Set *err_msg to NULL and return 0 otherwise.

An error message is an UTF-8 encoded string.

If config has an exit code, format the exit code as an error message.

The error message remains valid until another PyInitConfig function is called with config. The caller doesn’t have to free the error message.

int PyInitConfig_GetExitCode(PyInitConfig *config, int *exitcode)

Get the config exit code.

Set *exitcode and return 1 if config has an exit code set.

Return 0 if config has no exit code set.

Only the Py_InitializeFromInitConfig() function can set an exit code if the parse_argv option is non-zero.

An exit code can be set when parsing the command line failed (exit code 2) or when a command line option asks to display the command line help (exit code 0).

Get Options

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

int PyInitConfig_HasOption(PyInitConfig *config, const char *name)

Test if the configuration has an option called name.

Return 1 if the option exists, or return 0 otherwise.

int PyInitConfig_GetInt(PyInitConfig *config, const char *name, int64_t *value)

Get an integer configuration option.

Set *value, and return 0 on success.

Set an error in config and return -1 on error.

int PyInitConfig_GetStr(PyInitConfig *config, const char *name, char **value)

Get a string configuration option as a null-terminated UTF-8 encoded string.

Set *value, and return 0 on success.

Set an error in config and return -1 on error.

*value can be set to NULL if the option is an optional string and the option is unset.

On success, the string must be released with free(value) if it’s not NULL.

int PyInitConfig_GetStrList(PyInitConfig *config, const char *name, size_t *length, char ***items)

Get a string list configuration option as an array of null-terminated UTF-8 encoded strings.

Set *length and *value, and return 0 on success.

Set an error in config and return -1 on error.

On success, the string list must be released with PyInitConfig_FreeStrList(length, items).

void PyInitConfig_FreeStrList(size_t length, char **items)

Free memory of a string list created by PyInitConfig_GetStrList().

Set Options

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

Some configuration options have side effects on other options. This logic is only implemented when Py_InitializeFromInitConfig() is called, not by the “Set” functions below. For example, setting dev_mode to 1 does not set faulthandler to 1.

int PyInitConfig_SetInt(PyInitConfig *config, const char *name, int64_t value)

Set an integer configuration option.

Return 0 on success.

Set an error in config and return -1 on error.

int PyInitConfig_SetStr(PyInitConfig *config, const char *name, const char *value)

Set a string configuration option from a null-terminated UTF-8 encoded string. The string is copied.

Return 0 on success.

Set an error in config and return -1 on error.

int PyInitConfig_SetStrList(PyInitConfig *config, const char *name, size_t length, char *const *items)

Set a string list configuration option from an array of null-terminated UTF-8 encoded strings. The string list is copied.

Return 0 on success.

Set an error in config and return -1 on error.

Module

int PyInitConfig_AddModule(PyInitConfig *config, const char *name, PyObject *(*initfunc)(void))

Add a built-in extension module to the table of built-in modules.

The new module can be imported by the name name, and uses the function initfunc as the initialization function called on the first attempted import.

Return 0 on success.

Set an error in config and return -1 on error.

If Python is initialized multiple times, PyInitConfig_AddModule() must be called at each Python initialization.

Similar to the PyImport_AppendInittab() function.

Initialize Python

int Py_InitializeFromInitConfig(PyInitConfig *config)

Initialize Python from the initialization configuration.

Return 0 on success.

Set an error in config and return -1 on error.

Set an exit code in config and return -1 if Python wants to exit.

See PyInitConfig_GetExitcode() for the exit code case.

Example

Example initializing Python, set configuration options of various types, return -1 on error:

int init_python(void)
{
    PyInitConfig *config = PyInitConfig_Create();
    if (config == NULL) {
        printf("PYTHON INIT ERROR: memory allocation failed\n");
        return -1;
    }

    // Set an integer (dev mode)
    if (PyInitConfig_SetInt(config, "dev_mode", 1) < 0) {
        goto error;
    }

    // Set a list of UTF-8 strings (argv)
    char *argv[] = {"my_program", "-c", "pass"};
    if (PyInitConfig_SetStrList(config, "argv",
                                 Py_ARRAY_LENGTH(argv), argv) < 0) {
        goto error;
    }

    // Set a UTF-8 string (program name)
    if (PyInitConfig_SetStr(config, "program_name", L"my_program") < 0) {
        goto error;
    }

    // Initialize Python with the configuration
    if (Py_InitializeFromInitConfig(config) < 0) {
        goto error;
    }
    PyInitConfig_Free(config);
    return 0;

error:
    {
        // Display the error message
        // This uncommon braces style is used, because you cannot make
        // goto targets point to variable declarations.
        const char *err_msg;
        (void)PyInitConfig_GetError(config, &err_msg);
        printf("PYTHON INIT ERROR: %s\n", err_msg);
        PyInitConfig_Free(config);

        return -1;
    }
}

Runtime Python configuration API

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

Some options are read from the sys attributes. For example, the option "argv" is read from sys.argv.

PyObject *PyConfig_Get(const char *name)

Get the current runtime value of a configuration option as a Python object.

Return a new reference on success.

Set an exception and return NULL on error.

The object type depends on the configuration option. It can be:

bool

int

str

list[str]

dict[str, str]

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Added in version 3.14.

int PyConfig_GetInt(const char *name, int *value)

Similar to PyConfig_Get(), but get the value as a C int.

Return 0 on success.

Set an exception and return -1 on error.

Added in version 3.14.

PyObject *PyConfig_Names(void)

Get all configuration option names as a frozenset.

Return a new reference on success.

Set an exception and return NULL on error.

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Added in version 3.14.

int PyConfig_Set(const char *name, PyObject *value)

Set the current runtime value of a configuration option.

Raise a ValueError if there is no option name.

Raise a ValueError if value is an invalid value.

Raise a ValueError if the option is read-only (cannot be set).

Raise a TypeError if value has not the proper type.

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Added in version 3.14.

Py_GetArgcArgv()

void Py_GetArgcArgv(int *argc, wchar_t ***argv)

파이썬이 수정하기 전의, 원래 명령 줄 인자를 가져옵니다.

See also PyConfig.orig_argv member.

다단계 초기화 비공개 잠정적 API

This section is a private provisional API introducing multi-phase initialization, the core feature of PEP 432 [https://peps.python.org/pep-0432/]:

“핵심(Core)” 초기화 단계, “최소한의 파이썬”:

내장형;

내장 예외;

내장과 프로즌 모듈(frozen modules);

sys 모듈은 부분적으로만 초기화됩니다 (예를 들어: sys.path는 아직 존재하지 않습니다).

“주(Main)” 초기화 단계, 파이썬이 완전히 초기화됩니다:

importlib를 설치하고 구성합니다;

경로 구성을 적용합니다;

시그널 처리기를 설치합니다;

sys 모듈 초기화를 완료합니다 (예를 들어: sys.stdout과 sys.path를 만듭니다);

faulthandler와 tracemalloc과 같은 선택적 기능을 활성화합니다;

site 모듈을 임포트 합니다;

등등

비공개 잠정적 API:

PyConfig._init_main: if set to 0, Py_InitializeFromConfig() stops at the “Core” initialization phase.

PyStatus _Py_InitializeMain(void)

“주” 초기화 단계로 이동하여, 파이썬 초기화를 완료합니다.

“핵심” 단계에서는 아무런 모듈도 임포트 하지 않고 importlib 모듈이 구성되지 않습니다: 경로 구성은 “주” 단계에서만 적용됩니다. 경로 구성을 재정의하거나 조정하기 위해 파이썬에서 파이썬을 사용자 정의할 수 있으며, 사용자 정의 sys.meta_path 임포터(importer)나 임포트 훅 등을 설치할 수 있습니다.

It may become possible to calculate the Path Configuration in Python, after the Core phase and before the Main phase, which is one of the PEP 432 [https://peps.python.org/pep-0432/] motivation.

“핵심” 단계가 제대로 정의되지 않았습니다: 이 단계에서 무엇을 사용할 수 있고, 무엇이 그렇지 않아야 하는지는 아직 지정되지 않았습니다. API는 비공개이자 잠정적인 것으로 표시됩니다: 적절한 공개 API가 설계될 때까지 언제든지 API를 수정하거나 제거할 수 있습니다.

“핵심”과 “주” 초기화 단계 사이에서 파이썬 코드를 실행하는 예제:

void init_python(void)
{
    PyStatus status;

    PyConfig config;
    PyConfig_InitPythonConfig(&config);
    config._init_main = 0;

    /* ... customize 'config' configuration ... */

    status = Py_InitializeFromConfig(&config);
    PyConfig_Clear(&config);
    if (PyStatus_Exception(status)) {
        Py_ExitStatusException(status);
    }

    /* Use sys.stderr because sys.stdout is only created
       by _Py_InitializeMain() */
    int res = PyRun_SimpleString(
        "import sys; "
        "print('Run Python code before _Py_InitializeMain', "
               "file=sys.stderr)");
    if (res < 0) {
        exit(1);
    }

    /* ... put more configuration code here ... */

    status = _Py_InitializeMain();
    if (PyStatus_Exception(status)) {
        Py_ExitStatusException(status);
    }
}

메모리 관리

개요

파이썬의 메모리 관리에는 모든 파이썬 객체와 데이터 구조를 포함하는 비공개 힙(private heap)을 수반합니다. 이 비공개 힙의 관리는 파이썬 메모리 관리자에 의해 내부적으로 이루어집니다. 파이썬 메모리 관리자는 공유, 세그먼트 화, 사전 할당 또는 캐싱과 같은 동적 스토리지 관리의 다양한 측면을 처리하는 서로 다른 구성 요소를 가지고 있습니다.

가장 낮은 수준에서, 원시 메모리 할당자는 운영 체제의 메모리 관리자와 상호 작용하여 비공개 힙에 모든 파이썬 관련 데이터를 저장하기에 충분한 공간이 있는지 확인합니다. 원시 메모리 할당자 위에, 여러 개의 객체별 할당자가 같은 힙에서 작동하며 각 객체 형의 특성에 맞는 고유한 메모리 관리 정책을 구현합니다. 예를 들어, 정수는 다른 스토리지 요구 사항과 속도/공간 절충을 의미하므로, 정수 객체는 힙 내에서 문자열, 튜플 또는 딕셔너리와는 다르게 관리됩니다. 따라서 파이썬 메모리 관리자는 일부 작업을 객체별 할당자에게 위임하지만, 후자가 비공개 힙의 경계 내에서 작동하도록 합니다.

파이썬 힙의 관리는 인터프리터 자체에 의해 수행되며, 사용자는 힙 내부의 메모리 블록에 대한 객체 포인터를 규칙적으로 조작하더라도, 사용자가 제어할 수 없다는 것을 이해하는 것이 중요합니다. 파이썬 객체와 기타 내부 버퍼를 위한 힙 공간 할당은 이 설명서에 나열된 파이썬/C API 함수를 통해 파이썬 메모리 관리자의 요청에 따라 수행됩니다.

메모리 손상을 피하고자, 확장 작성자는 C 라이브러리에서 내보낸 함수를 파이썬 객체에 대해 실행하지 않아야 합니다: malloc(), calloc(), realloc() 및 free(). 그렇게 한다면, 서로 다른 알고리즘을 구현하고 다른 힘에 작동하기 때문에, C 할당자와 파이썬 메모리 관리자 간에 혼합 호출이 발생하여 치명적인 결과를 초래합니다. 그러나, 다음 예제와 같이 개별 목적으로 C 라이브러리 할당자를 사용하여 메모리 블록을 안전하게 할당하고 해제할 수 있습니다:

PyObject *res;
char *buf = (char *) malloc(BUFSIZ); /* for I/O */

if (buf == NULL)
    return PyErr_NoMemory();
...Do some I/O operation involving buf...
res = PyBytes_FromString(buf);
free(buf); /* malloc'ed */
return res;

이 예에서, I/O 버퍼에 대한 메모리 요청은 C 라이브러리 할당자에 의해 처리됩니다. 파이썬 메모리 관리자는 결과로 반환되는 바이트열 객체의 할당에만 관여합니다.

In most situations, however, it is recommended to allocate memory from the Python heap specifically because the latter is under control of the Python memory manager. For example, this is required when the interpreter is extended with new object types written in C. Another reason for using the Python heap is the desire to inform the Python memory manager about the memory needs of the extension module. Even when the requested memory is used exclusively for internal, highly specific purposes, delegating all memory requests to the Python memory manager causes the interpreter to have a more accurate image of its memory footprint as a whole. Consequently, under certain circumstances, the Python memory manager may or may not trigger appropriate actions, like garbage collection, memory compaction or other preventive procedures. Note that by using the C library allocator as shown in the previous example, the allocated memory for the I/O buffer escapes completely the Python memory manager.

더 보기

PYTHONMALLOC 환경 변수를 사용하여 파이썬에서 사용하는 메모리 할당자를 구성할 수 있습니다.

PYTHONMALLOCSTATS 환경 변수는 새로운 pymalloc 객체 아레나(arena)가 만들어질 때마다 그리고 종료 시 pymalloc 메모리 할당자의 통계를 인쇄하는 데 사용될 수 있습니다.

Allocator Domains

All allocating functions belong to one of three different “domains” (see also PyMemAllocatorDomain). These domains represent different allocation strategies and are optimized for different purposes. The specific details on how every domain allocates memory or what internal functions each domain calls is considered an implementation detail, but for debugging purposes a simplified table can be found at here. The APIs used to allocate and free a block of memory must be from the same domain. For example, PyMem_Free() must be used to free memory allocated using PyMem_Malloc().

The three allocation domains are:

Raw domain: intended for allocating memory for general-purpose memory buffers where the allocation must go to the system allocator or where the allocator can operate without the GIL. The memory is requested directly from the system. See Raw Memory Interface.

“Mem” domain: intended for allocating memory for Python buffers and general-purpose memory buffers where the allocation must be performed with the GIL held. The memory is taken from the Python private heap. See Memory Interface.

Object domain: intended for allocating memory for Python objects. The memory is taken from the Python private heap. See Object allocators.

참고

The free-threaded build requires that only Python objects are allocated using the “object” domain and that all Python objects are allocated using that domain. This differs from the prior Python versions, where this was only a best practice and not a hard requirement.

For example, buffers (non-Python objects) should be allocated using PyMem_Malloc(), PyMem_RawMalloc(), or malloc(), but not PyObject_Malloc().

See Memory Allocation APIs.

원시 메모리 인터페이스

다음 함수 집합은 시스템 할당자에 대한 래퍼입니다. 이러한 함수는 스레드 안전해서, GIL을 유지할 필요는 없습니다.

The default raw memory allocator uses the following functions: malloc(), calloc(), realloc() and free(); call malloc(1) (or calloc(1, 1)) when requesting zero bytes.

Added in version 3.4.

void *PyMem_RawMalloc(size_t n)

Part of the Stable ABI since version 3.13.

Allocates n bytes and returns a pointer of type void* to the allocated memory, or NULL if the request fails.

0바이트를 요청하면 가능하면 PyMem_RawMalloc(1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다. 메모리는 어떤 식으로든 초기화되지 않습니다.

void *PyMem_RawCalloc(size_t nelem, size_t elsize)

Part of the Stable ABI since version 3.13.

Allocates nelem elements each whose size in bytes is elsize and returns a pointer of type void* to the allocated memory, or NULL if the request fails. The memory is initialized to zeros.

0개의 요소나 0바이트 크기의 요소를 요청하면 PyMem_RawCalloc(1, 1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다.

Added in version 3.5.

void *PyMem_RawRealloc(void *p, size_t n)

Part of the Stable ABI since version 3.13.

p가 가리키는 메모리 블록의 크기를 n 바이트로 조정합니다. 내용은 이전과 새로운 크기의 최솟값 내에서는 변경되지 않습니다.

p가 NULL이면, 호출은 PyMem_RawMalloc(n)과 동등합니다; n이 0과 같으면, 메모리 블록의 크기는 조정되지만 해제되지는 않고, 반환된 포인터는 NULL이 아닙니다.

p가 NULL이 아닌 한, PyMem_RawMalloc(), PyMem_RawRealloc() 또는 PyMem_RawCalloc()에 대한 이전 호출에 의해 반환된 것이어야 합니다.

요청이 실패하면, PyMem_RawRealloc()은 NULL을 반환하고 p는 이전 메모리 영역에 대한 유효한 포인터로 유지됩니다.

void PyMem_RawFree(void *p)

Part of the Stable ABI since version 3.13.

p가 가리키는 메모리 블록을 해제합니다. p는 PyMem_RawMalloc(), PyMem_RawRealloc() 또는 PyMem_RawCalloc()에 대한 이전 호출로 반환된 것이어야 합니다. 그렇지 않거나 PyMem_RawFree(p)가 앞서 호출되었으면, 정의되지 않은 동작이 일어납니다.

p가 NULL이면, 아무 작업도 수행되지 않습니다.

메모리 인터페이스

ANSI C 표준에 따라 모델링 되었지만 0바이트를 요청할 때의 동작을 지정한 다음 함수 집합은 파이썬 힙에서 메모리를 할당하고 해제하는 데 사용할 수 있습니다.

기본 메모리 할당자는 pymalloc 메모리 할당자를 사용합니다.

경고

이 함수를 사용할 때는 GIL을 유지해야 합니다.

버전 3.6에서 변경: 기본 할당자는 이제 시스템 malloc() 대신 pymalloc 입니다.

void *PyMem_Malloc(size_t n)

Part of the Stable ABI.

Allocates n bytes and returns a pointer of type void* to the allocated memory, or NULL if the request fails.

0바이트를 요청하면 PyMem_Malloc(1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다. 메모리는 어떤 식으로든 초기화되지 않습니다.

void *PyMem_Calloc(size_t nelem, size_t elsize)

Part of the Stable ABI since version 3.7.

Allocates nelem elements each whose size in bytes is elsize and returns a pointer of type void* to the allocated memory, or NULL if the request fails. The memory is initialized to zeros.

0개의 요소나 0바이트 크기의 요소를 요청하면 PyMem_Calloc(1, 1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다.

Added in version 3.5.

void *PyMem_Realloc(void *p, size_t n)

Part of the Stable ABI.

p가 가리키는 메모리 블록의 크기를 n 바이트로 조정합니다. 내용은 이전과 새로운 크기의 최솟값 내에서는 변경되지 않습니다.

p가 NULL이면, 호출은 PyMem_Malloc(n)과 동등합니다; 그렇지 않고 n이 0과 같으면, 메모리 블록의 크기는 조정되지만 해제되지는 않으며, 반환된 포인터는 NULL이 아닙니다.

p가 NULL이 아닌 한, PyMem_Malloc(), PyMem_Realloc() 또는 PyMem_Calloc()에 대한 이전 호출이 반환한 것이어야 합니다.

요청이 실패하면, PyMem_Realloc()은 NULL을 반환하고 p는 이전 메모리 영역에 대한 유효한 포인터로 유지됩니다.

void PyMem_Free(void *p)

Part of the Stable ABI.

p가 가리키는 메모리 블록을 해제합니다. p는 PyMem_Malloc(), PyMem_Realloc() 또는 PyMem_Calloc()에 대한 이전 호출이 반환한 것이어야 합니다. 그렇지 않거나 PyMem_Free(p)가 앞서 호출되었으면 정의되지 않은 동작이 일어납니다.

p가 NULL이면, 아무 작업도 수행되지 않습니다.

편의를 위해 다음과 같은 형 지향 매크로가 제공됩니다. TYPE이 모든 C형을 나타냄에 유의하십시오.

PyMem_New(TYPE, n)

Same as PyMem_Malloc(), but allocates (n * sizeof(TYPE)) bytes of memory. Returns a pointer cast to TYPE*. The memory will not have been initialized in any way.

PyMem_Resize(p, TYPE, n)

Same as PyMem_Realloc(), but the memory block is resized to (n * sizeof(TYPE)) bytes. Returns a pointer cast to TYPE*. On return, p will be a pointer to the new memory area, or NULL in the event of failure.

이것은 C 전처리기 매크로입니다; p는 항상 다시 대입됩니다. 에러를 처리할 때 메모리 손실을 피하려면 p의 원래 값을 보관하십시오.

void PyMem_Del(void *p)

PyMem_Free()와 같습니다.

또한, 위에 나열된 C API 함수를 사용하지 않고, 파이썬 메모리 할당자를 직접 호출하기 위해 다음 매크로 집합이 제공됩니다. 그러나, 이들을 사용하면 파이썬 버전을 가로지르는 바이너리 호환성이 유지되지 않아서 확장 모듈에서는 폐지되었습니다.

PyMem_MALLOC(size)

PyMem_NEW(type, size)

PyMem_REALLOC(ptr, size)

PyMem_RESIZE(ptr, type, size)

PyMem_FREE(ptr)

PyMem_DEL(ptr)

객체 할당자

ANSI C 표준에 따라 모델링 되었지만 0바이트를 요청할 때의 동작을 지정한 다음 함수 집합은 파이썬 힙에서 메모리를 할당하고 해제하는 데 사용할 수 있습니다.

참고

There is no guarantee that the memory returned by these allocators can be successfully cast to a Python object when intercepting the allocating functions in this domain by the methods described in the Customize Memory Allocators section.

기본 객체 할당자는 pymalloc 메모리 할당자를 사용합니다.

경고

이 함수를 사용할 때는 GIL을 유지해야 합니다.

void *PyObject_Malloc(size_t n)

Part of the Stable ABI.

Allocates n bytes and returns a pointer of type void* to the allocated memory, or NULL if the request fails.

0바이트를 요청하면 PyObject_Malloc(1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다. 메모리는 어떤 식으로든 초기화되지 않습니다.

void *PyObject_Calloc(size_t nelem, size_t elsize)

Part of the Stable ABI since version 3.7.

Allocates nelem elements each whose size in bytes is elsize and returns a pointer of type void* to the allocated memory, or NULL if the request fails. The memory is initialized to zeros.

0개의 요소나 0바이트 크기의 요소를 요청하면 PyObject_Calloc(1, 1)이 대신 호출된 것처럼 가능하면 고유한 NULL이 아닌 포인터를 반환합니다.

Added in version 3.5.

void *PyObject_Realloc(void *p, size_t n)

Part of the Stable ABI.

p가 가리키는 메모리 블록의 크기를 n 바이트로 조정합니다. 내용은 이전과 새로운 크기의 최솟값 내에서는 변경되지 않습니다.

p가 NULL이면, 호출은 PyObject_Malloc(n)과 동등합니다; 그렇지 않고 n이 0과 같으면, 메모리 블록의 크기는 조정되지만 해제되지 않고, 반환된 포인터는 NULL이 아닙니다.

p가 NULL이 아닌 한, PyObject_Malloc(), PyObject_Realloc() 또는 PyObject_Calloc()에 대한 이전 호출에 의해 반환된 것이어야 합니다.

요청이 실패하면, PyObject_Realloc()은 NULL을 반환하고 p는 이전 메모리 영역에 대한 유효한 포인터로 유지됩니다.

void PyObject_Free(void *p)

Part of the Stable ABI.

p가 가리키는 메모리 블록을 해제합니다. 이 블록은 PyObject_Malloc(), PyObject_Realloc() 또는 PyObject_Calloc()에 대한 이전 호출에 의해 반환된 것이어야 합니다. 그렇지 않거나 PyObject_Free(p)가 이전에 호출되었으면 정의되지 않은 동작이 일어납니다.

p가 NULL이면, 아무 작업도 수행되지 않습니다.

기본 메모리 할당자

기본 메모리 할당자:

구성

이름

PyMem_RawMalloc

PyMem_Malloc

PyObject_Malloc

릴리스 빌드

"pymalloc"

malloc

pymalloc

pymalloc

디버그 빌드

"pymalloc_debug"

malloc + 디버그

pymalloc + 디버그

pymalloc + 디버그

pymalloc 없는 배포 빌드

"malloc"

malloc

malloc

malloc

pymalloc 없는 디버그 빌드

"malloc_debug"

malloc + 디버그

malloc + 디버그

malloc + 디버그

범례:

Name: value for PYTHONMALLOC environment variable.

malloc: system allocators from the standard C library, C functions: malloc(), calloc(), realloc() and free().

pymalloc: pymalloc memory allocator.

mimalloc: mimalloc memory allocator. The pymalloc allocator will be used if mimalloc support isn’t available.

“+ debug”: with debug hooks on the Python memory allocators.

“Debug build”: Python build in debug mode.

메모리 할당자 사용자 정의

Added in version 3.4.

type PyMemAllocatorEx

Structure used to describe a memory block allocator. The structure has the following fields:

필드

의미

void *ctx

첫 번째 인자로 전달된 사용자 컨텍스트

void* malloc(void *ctx, size_t size)

메모리 블록을 할당합니다

void* calloc(void *ctx, size_t nelem, size_t elsize)

0으로 초기화된 메모리 블록을 할당합니다

void* realloc(void *ctx, void *ptr, size_t new_size)

메모리 블록을 할당하거나 크기 조정합니다

void free(void *ctx, void *ptr)

메모리 블록을 해제합니다

버전 3.5에서 변경: The PyMemAllocator structure was renamed to PyMemAllocatorEx and a new calloc field was added.

type PyMemAllocatorDomain

할당자 도메인을 식별하는 데 사용되는 열거형. 도메인:

PYMEM_DOMAIN_RAW

함수:

PyMem_RawMalloc()

PyMem_RawRealloc()

PyMem_RawCalloc()

PyMem_RawFree()

PYMEM_DOMAIN_MEM

함수:

PyMem_Malloc(),

PyMem_Realloc()

PyMem_Calloc()

PyMem_Free()

PYMEM_DOMAIN_OBJ

함수:

PyObject_Malloc()

PyObject_Realloc()

PyObject_Calloc()

PyObject_Free()

void PyMem_GetAllocator(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)

지정된 도메인의 메모리 블록 할당자를 가져옵니다.

void PyMem_SetAllocator(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)

지정된 도메인의 메모리 블록 할당자를 설정합니다.

새 할당자는 0바이트를 요청할 때 고유한 NULL이 아닌 포인터를 반환해야 합니다.

For the PYMEM_DOMAIN_RAW domain, the allocator must be thread-safe: the GIL is not held when the allocator is called.

For the remaining domains, the allocator must also be thread-safe: the allocator may be called in different interpreters that do not share a GIL.

새 할당자가 훅이 아니면 (이전 할당자를 호출하지 않으면), PyMem_SetupDebugHooks() 함수를 호출하여 새 할당자 위에 디버그 훅을 다시 설치해야 합니다.

See also PyPreConfig.allocator and Preinitialize Python with PyPreConfig.

경고

PyMem_SetAllocator() does have the following contract:

It can be called after Py_PreInitialize() and before Py_InitializeFromConfig() to install a custom memory allocator. There are no restrictions over the installed allocator other than the ones imposed by the domain (for instance, the Raw Domain allows the allocator to be called without the GIL held). See the section on allocator domains for more information.

If called after Python has finish initializing (after Py_InitializeFromConfig() has been called) the allocator must wrap the existing allocator. Substituting the current allocator for some other arbitrary one is not supported.

버전 3.12에서 변경: All allocators must be thread-safe.

void PyMem_SetupDebugHooks(void)

Setup debug hooks in the Python memory allocators to detect memory errors.

Debug hooks on the Python memory allocators

When Python is built in debug mode, the PyMem_SetupDebugHooks() function is called at the Python preinitialization to setup debug hooks on Python memory allocators to detect memory errors.

The PYTHONMALLOC environment variable can be used to install debug hooks on a Python compiled in release mode (ex: PYTHONMALLOC=debug).

The PyMem_SetupDebugHooks() function can be used to set debug hooks after calling PyMem_SetAllocator().

These debug hooks fill dynamically allocated memory blocks with special, recognizable bit patterns. Newly allocated memory is filled with the byte 0xCD (PYMEM_CLEANBYTE), freed memory is filled with the byte 0xDD (PYMEM_DEADBYTE). Memory blocks are surrounded by “forbidden bytes” filled with the byte 0xFD (PYMEM_FORBIDDENBYTE). Strings of these bytes are unlikely to be valid addresses, floats, or ASCII strings.

실행 시간 검사:

Detect API violations. For example, detect if PyObject_Free() is called on a memory block allocated by PyMem_Malloc().

Detect write before the start of the buffer (buffer underflow).

Detect write after the end of the buffer (buffer overflow).

Check that the GIL is held when allocator functions of PYMEM_DOMAIN_OBJ (ex: PyObject_Malloc()) and PYMEM_DOMAIN_MEM (ex: PyMem_Malloc()) domains are called.

에러가 발생하면, 디버그 훅은 tracemalloc 모듈을 사용하여 메모리 블록이 할당된 곳의 트레이스백을 가져옵니다. tracemalloc이 파이썬 메모리 할당을 추적 중이고 메모리 블록이 추적될 때만 트레이스백이 표시됩니다.

Let S = sizeof(size_t). 2*S bytes are added at each end of each block of N bytes requested. The memory layout is like so, where p represents the address returned by a malloc-like or realloc-like function (p[i:j] means the slice of bytes from *(p+i) inclusive up to *(p+j) exclusive; note that the treatment of negative indices differs from a Python slice):

p[-2*S:-S]

Number of bytes originally asked for. This is a size_t, big-endian (easier to read in a memory dump).

p[-S]

API identifier (ASCII character):

'r' for PYMEM_DOMAIN_RAW.

'm' for PYMEM_DOMAIN_MEM.

'o' for PYMEM_DOMAIN_OBJ.

p[-S+1:0]

Copies of PYMEM_FORBIDDENBYTE. Used to catch under- writes and reads.

p[0:N]

The requested memory, filled with copies of PYMEM_CLEANBYTE, used to catch reference to uninitialized memory. When a realloc-like function is called requesting a larger memory block, the new excess bytes are also filled with PYMEM_CLEANBYTE. When a free-like function is called, these are overwritten with PYMEM_DEADBYTE, to catch reference to freed memory. When a realloc- like function is called requesting a smaller memory block, the excess old bytes are also filled with PYMEM_DEADBYTE.

p[N:N+S]

Copies of PYMEM_FORBIDDENBYTE. Used to catch over- writes and reads.

p[N+S:N+2*S]

Only used if the PYMEM_DEBUG_SERIALNO macro is defined (not defined by default).

A serial number, incremented by 1 on each call to a malloc-like or realloc-like function. Big-endian size_t. If “bad memory” is detected later, the serial number gives an excellent way to set a breakpoint on the next run, to capture the instant at which this block was passed out. The static function bumpserialno() in obmalloc.c is the only place the serial number is incremented, and exists so you can set such a breakpoint easily.

A realloc-like or free-like function first checks that the PYMEM_FORBIDDENBYTE bytes at each end are intact. If they’ve been altered, diagnostic output is written to stderr, and the program is aborted via Py_FatalError(). The other main failure mode is provoking a memory error when a program reads up one of the special bit patterns and tries to use it as an address. If you get in a debugger then and look at the object, you’re likely to see that it’s entirely filled with PYMEM_DEADBYTE (meaning freed memory is getting used) or PYMEM_CLEANBYTE (meaning uninitialized memory is getting used).

버전 3.6에서 변경: The PyMem_SetupDebugHooks() function now also works on Python compiled in release mode. On error, the debug hooks now use tracemalloc to get the traceback where a memory block was allocated. The debug hooks now also check if the GIL is held when functions of PYMEM_DOMAIN_OBJ and PYMEM_DOMAIN_MEM domains are called.

버전 3.8에서 변경: Byte patterns 0xCB (PYMEM_CLEANBYTE), 0xDB (PYMEM_DEADBYTE) and 0xFB (PYMEM_FORBIDDENBYTE) have been replaced with 0xCD, 0xDD and 0xFD to use the same values than Windows CRT debug malloc() and free().

pymalloc 할당자

Python has a pymalloc allocator optimized for small objects (smaller or equal to 512 bytes) with a short lifetime. It uses memory mappings called “arenas” with a fixed size of either 256 KiB on 32-bit platforms or 1 MiB on 64-bit platforms. It falls back to PyMem_RawMalloc() and PyMem_RawRealloc() for allocations larger than 512 bytes.

pymalloc is the default allocator of the PYMEM_DOMAIN_MEM (ex: PyMem_Malloc()) and PYMEM_DOMAIN_OBJ (ex: PyObject_Malloc()) domains.

아레나 할당자는 다음 함수를 사용합니다:

VirtualAlloc() and VirtualFree() on Windows,

mmap() and munmap() if available,

그렇지 않으면 malloc()과 free()

This allocator is disabled if Python is configured with the --without-pymalloc option. It can also be disabled at runtime using the PYTHONMALLOC environment variable (ex: PYTHONMALLOC=malloc).

pymalloc 아레나 할당자 사용자 정의

Added in version 3.4.

type PyObjectArenaAllocator

아레나 할당자를 기술하는 데 사용되는 구조체. 이 구조체에는 세 개의 필드가 있습니다:

필드

의미

void *ctx

첫 번째 인자로 전달된 사용자 컨텍스트

void* alloc(void *ctx, size_t size)

size 바이트의 아레나를 할당합니다

void free(void *ctx, void *ptr, size_t size)

아레나를 해제합니다

void PyObject_GetArenaAllocator(PyObjectArenaAllocator *allocator)

아레나 할당자를 얻습니다.

void PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator)

아레나 할당자를 설정합니다.

The mimalloc allocator

Added in version 3.13.

Python supports the mimalloc allocator when the underlying platform support is available. mimalloc “is a general purpose allocator with excellent performance characteristics. Initially developed by Daan Leijen for the runtime systems of the Koka and Lean languages.”

tracemalloc C API

Added in version 3.7.

int PyTraceMalloc_Track(unsigned int domain, uintptr_t ptr, size_t size)

tracemalloc 모듈에서 할당된 메모리 블록을 추적합니다.

성공하면 0을 반환하고, 에러가 발생하면 (추적을 저장하기 위한 메모리를 할당하지 못했습니다) -1을 반환합니다. tracemalloc이 비활성화되었으면 -2를 반환합니다.

메모리 블록이 이미 추적되면, 기존 추적을 갱신합니다.

int PyTraceMalloc_Untrack(unsigned int domain, uintptr_t ptr)

tracemalloc 모듈에서 할당된 메모리 블록을 추적 해제합니다. 블록이 추적되지 않으면 아무것도 하지 않습니다.

tracemalloc이 비활성화되었으면 -2를 반환하고, 그렇지 않으면 0을 반환합니다.

예

다음은 개요 섹션에서 따온 예제입니다. I/O 버퍼가 첫 번째 함수 집합을 사용하여 파이썬 힙에서 할당되도록 다시 작성되었습니다:

PyObject *res;
char *buf = (char *) PyMem_Malloc(BUFSIZ); /* for I/O */

if (buf == NULL)
    return PyErr_NoMemory();
/* ...Do some I/O operation involving buf... */
res = PyBytes_FromString(buf);
PyMem_Free(buf); /* allocated with PyMem_Malloc */
return res;

형 지향 함수 집합을 사용하는 같은 코드입니다:

PyObject *res;
char *buf = PyMem_New(char, BUFSIZ); /* for I/O */

if (buf == NULL)
    return PyErr_NoMemory();
/* ...Do some I/O operation involving buf... */
res = PyBytes_FromString(buf);
PyMem_Free(buf); /* allocated with PyMem_New */
return res;

위의 두 가지 예에서, 버퍼는 항상 같은 집합에 속하는 함수를 통해 조작됨에 유의하십시오. 실제로, 서로 다른 할당자를 혼합할 위험이 최소로 줄어들도록, 주어진 메모리 블록에 대해 같은 메모리 API 패밀리를 사용하는 것은 필수입니다 . 다음 코드 시퀀스에는 두 개의 에러가 있으며, 그중 하나는 서로 다른 힙에서 작동하는 두 개의 다른 할당자를 혼합하기 때문에 치명적(fatal)인 것으로 표시됩니다.

char *buf1 = PyMem_New(char, BUFSIZ);
char *buf2 = (char *) malloc(BUFSIZ);
char *buf3 = (char *) PyMem_Malloc(BUFSIZ);
...
PyMem_Del(buf3);  /* Wrong -- should be PyMem_Free() */
free(buf2);       /* Right -- allocated via malloc() */
free(buf1);       /* Fatal -- should be PyMem_Free()  */

In addition to the functions aimed at handling raw memory blocks from the Python heap, objects in Python are allocated and released with PyObject_New, PyObject_NewVar and PyObject_Free().

이것들은 C로 새로운 객체 형을 정의하고 구현하는 것에 대한 다음 장에서 설명될 것입니다.

객체 구현 지원

이 장에서는 새 객체 형을 정의할 때 사용되는 함수, 형 및 매크로에 관해 설명합니다.

힙에 객체 할당하기

공통 객체 구조체

기본 객체 형과 매크로

함수와 메서드 구현

확장형의 어트리뷰트 액세스

Member flags

Member types

Defining Getters and Setters

형 객체

간략 참조

“tp 슬롯”

서브 슬롯

슬롯 typedef

PyTypeObject 정의

PyObject 슬롯

PyVarObject 슬롯

PyTypeObject 슬롯

Static Types

힙 형

숫자 객체 구조체

매핑 객체 구조체

시퀀스 객체 구조체

버퍼 객체 구조체

비동기 객체 구조체

슬롯 형 typedef

예

순환 가비지 수집 지원

Controlling the Garbage Collector State

Querying Garbage Collector State

힙에 객체 할당하기

PyObject *_PyObject_New(PyTypeObject *type)

Return value: New reference.

PyVarObject *_PyObject_NewVar(PyTypeObject *type, Py_ssize_t size)

Return value: New reference.

PyObject *PyObject_Init(PyObject *op, PyTypeObject *type)

Return value: Borrowed reference. Part of the Stable ABI.

Initialize a newly allocated object op with its type and initial reference. Returns the initialized object. Other fields of the object are not affected.

PyVarObject *PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)

Return value: Borrowed reference. Part of the Stable ABI.

이것은 PyObject_Init()가 수행하는 모든 작업을 수행하고, 가변 크기 객체의 길이 정보도 초기화합니다.

PyObject_New(TYPE, typeobj)

Allocate a new Python object using the C structure type TYPE and the Python type object typeobj (PyTypeObject*). Fields not defined by the Python object header are not initialized. The caller will own the only reference to the object (i.e. its reference count will be one). The size of the memory allocation is determined from the tp_basicsize field of the type object.

PyObject_NewVar(TYPE, typeobj, size)

Allocate a new Python object using the C structure type TYPE and the Python type object typeobj (PyTypeObject*). Fields not defined by the Python object header are not initialized. The allocated memory allows for the TYPE structure plus size (Py_ssize_t) fields of the size given by the tp_itemsize field of typeobj. This is useful for implementing objects like tuples, which are able to determine their size at construction time. Embedding the array of fields into the same allocation decreases the number of allocations, improving the memory management efficiency.

void PyObject_Del(void *op)

Same as PyObject_Free().

PyObject _Py_NoneStruct

파이썬에서 None으로 노출되는 객체. 이 객체에 대한 포인터로 평가되는 Py_None 매크로를 사용해서 액세스해야 합니다.

더 보기

PyModule_Create()

확장 모듈을 할당하고 만듭니다.

공통 객체 구조체

파이썬의 객체 형 정의에 사용되는 많은 구조체가 있습니다. 이 섹션에서는 이러한 구조체와 사용 방법에 관해 설명합니다.

기본 객체 형과 매크로

All Python objects ultimately share a small number of fields at the beginning of the object’s representation in memory. These are represented by the PyObject and PyVarObject types, which are defined, in turn, by the expansions of some macros also used, whether directly or indirectly, in the definition of all other Python objects. Additional macros can be found under reference counting.

type PyObject

Part of the Limited API. (Only some members are part of the stable ABI.)

All object types are extensions of this type. This is a type which contains the information Python needs to treat a pointer to an object as an object. In a normal “release” build, it contains only the object’s reference count and a pointer to the corresponding type object. Nothing is actually declared to be a PyObject, but every pointer to a Python object can be cast to a PyObject*. Access to the members must be done by using the macros Py_REFCNT and Py_TYPE.

type PyVarObject

Part of the Limited API. (Only some members are part of the stable ABI.)

This is an extension of PyObject that adds the ob_size field. This is only used for objects that have some notion of length. This type does not often appear in the Python/C API. Access to the members must be done by using the macros Py_REFCNT, Py_TYPE, and Py_SIZE.

PyObject_HEAD

길이가 변하지 않는 객체를 나타내는 새로운 형을 선언할 때 사용되는 매크로입니다. PyObject_HEAD 매크로는 다음과 같이 확장됩니다:

PyObject ob_base;

위의 PyObject 설명서를 참조하십시오.

PyObject_VAR_HEAD

인스턴스마다 길이가 다른 객체를 나타내는 새로운 형을 선언할 때 사용되는 매크로입니다. PyObject_VAR_HEAD 매크로는 다음과 같이 확장됩니다:

PyVarObject ob_base;

위의 PyVarObject 설명서를 참조하십시오.

int Py_Is(PyObject *x, PyObject *y)

Part of the Stable ABI since version 3.10.

Test if the x object is the y object, the same as x is y in Python.

Added in version 3.10.

int Py_IsNone(PyObject *x)

Part of the Stable ABI since version 3.10.

Test if an object is the None singleton, the same as x is None in Python.

Added in version 3.10.

int Py_IsTrue(PyObject *x)

Part of the Stable ABI since version 3.10.

Test if an object is the True singleton, the same as x is True in Python.

Added in version 3.10.

int Py_IsFalse(PyObject *x)

Part of the Stable ABI since version 3.10.

Test if an object is the False singleton, the same as x is False in Python.

Added in version 3.10.

PyTypeObject *Py_TYPE(PyObject *o)

Return value: Borrowed reference. Part of the Stable ABI since version 3.14.

Get the type of the Python object o.

Return a borrowed reference.

Use the Py_SET_TYPE() function to set an object type.

버전 3.11에서 변경: Py_TYPE() is changed to an inline static function. The parameter type is no longer const PyObject*.

int Py_IS_TYPE(PyObject *o, PyTypeObject *type)

객체 o의 형이 type이면 0이 아닌 값을 반환합니다. 그렇지 않으면 0을 반환합니다. Py_TYPE(o) == type과 동등합니다.

Added in version 3.9.

void Py_SET_TYPE(PyObject *o, PyTypeObject *type)

객체 o의 형을 type으로 설정합니다.

Added in version 3.9.

Py_ssize_t Py_SIZE(PyVarObject *o)

Get the size of the Python object o.

Use the Py_SET_SIZE() function to set an object size.

버전 3.11에서 변경: Py_SIZE() is changed to an inline static function. The parameter type is no longer const PyVarObject*.

void Py_SET_SIZE(PyVarObject *o, Py_ssize_t size)

객체 o의 크기를 size로 설정합니다.

Added in version 3.9.

PyObject_HEAD_INIT(type)

이것은 새로운 PyObject 형의 초기화 값으로 확장되는 매크로입니다. 이 매크로는 다음으로 확장됩니다:

_PyObject_EXTRA_INIT
1, type,

PyVarObject_HEAD_INIT(type, size)

This is a macro which expands to initialization values for a new PyVarObject type, including the ob_size field. This macro expands to:

_PyObject_EXTRA_INIT
1, type, size,

함수와 메서드 구현

type PyCFunction

Part of the Stable ABI.

Type of the functions used to implement most Python callables in C. Functions of this type take two PyObject* parameters and return one such value. If the return value is NULL, an exception shall have been set. If not NULL, the return value is interpreted as the return value of the function as exposed in Python. The function must return a new reference.

함수 서명은 다음과 같습니다:

PyObject *PyCFunction(PyObject *self,
                      PyObject *args);

type PyCFunctionWithKeywords

Part of the Stable ABI.

Type of the functions used to implement Python callables in C with signature METH_VARARGS | METH_KEYWORDS. The function signature is:

PyObject *PyCFunctionWithKeywords(PyObject *self,
                                  PyObject *args,
                                  PyObject *kwargs);

type PyCFunctionFast

Part of the Stable ABI since version 3.13.

Type of the functions used to implement Python callables in C with signature METH_FASTCALL. The function signature is:

PyObject *PyCFunctionFast(PyObject *self,
                          PyObject *const *args,
                          Py_ssize_t nargs);

type PyCFunctionFastWithKeywords

Part of the Stable ABI since version 3.13.

Type of the functions used to implement Python callables in C with signature METH_FASTCALL | METH_KEYWORDS. The function signature is:

PyObject *PyCFunctionFastWithKeywords(PyObject *self,
                                      PyObject *const *args,
                                      Py_ssize_t nargs,
                                      PyObject *kwnames);

type PyCMethod

Type of the functions used to implement Python callables in C with signature METH_METHOD | METH_FASTCALL | METH_KEYWORDS. The function signature is:

PyObject *PyCMethod(PyObject *self,
                    PyTypeObject *defining_class,
                    PyObject *const *args,
                    Py_ssize_t nargs,
                    PyObject *kwnames)

Added in version 3.9.

type PyMethodDef

Part of the Stable ABI (including all members).

확장형의 메서드를 기술하는 데 사용되는 구조체. 이 구조체에는 네 개의 필드가 있습니다:

const char *ml_name

Name of the method.

PyCFunction ml_meth

Pointer to the C implementation.

int ml_flags

Flags bits indicating how the call should be constructed.

const char *ml_doc

Points to the contents of the docstring.

The ml_meth is a C function pointer. The functions may be of different types, but they always return PyObject*. If the function is not of the PyCFunction, the compiler will require a cast in the method table. Even though PyCFunction defines the first parameter as PyObject*, it is common that the method implementation uses the specific C type of the self object.

The ml_flags field is a bitfield which can include the following flags. The individual flags indicate either a calling convention or a binding convention.

다음과 같은 호출 규칙이 있습니다:

METH_VARARGS

This is the typical calling convention, where the methods have the type PyCFunction. The function expects two PyObject* values. The first one is the self object for methods; for module functions, it is the module object. The second parameter (often called args) is a tuple object representing all arguments. This parameter is typically processed using PyArg_ParseTuple() or PyArg_UnpackTuple().

METH_KEYWORDS

Can only be used in certain combinations with other flags: METH_VARARGS | METH_KEYWORDS, METH_FASTCALL | METH_KEYWORDS and METH_METHOD | METH_FASTCALL | METH_KEYWORDS.

METH_VARARGS | METH_KEYWORDS

이러한 플래그가 있는 메서드는 PyCFunctionWithKeywords 형이어야 합니다. 이 함수는 세 개의 매개 변수를 기대합니다: self, args, kwargs. 여기서 kwargs는 모든 키워드 인자의 딕셔너리이거나 키워드 인자가 없으면 NULL일 수 있습니다. 매개 변수는 일반적으로 PyArg_ParseTupleAndKeywords()를 사용하여 처리됩니다.

METH_FASTCALL

Fast calling convention supporting only positional arguments. The methods have the type PyCFunctionFast. The first parameter is self, the second parameter is a C array of PyObject* values indicating the arguments and the third parameter is the number of arguments (the length of the array).

Added in version 3.7.

버전 3.10에서 변경: METH_FASTCALL is now part of the stable ABI.

METH_FASTCALL | METH_KEYWORDS

Extension of METH_FASTCALL supporting also keyword arguments, with methods of type PyCFunctionFastWithKeywords. Keyword arguments are passed the same way as in the vectorcall protocol: there is an additional fourth PyObject* parameter which is a tuple representing the names of the keyword arguments (which are guaranteed to be strings) or possibly NULL if there are no keywords. The values of the keyword arguments are stored in the args array, after the positional arguments.

Added in version 3.7.

METH_METHOD

Can only be used in the combination with other flags: METH_METHOD | METH_FASTCALL | METH_KEYWORDS.

METH_METHOD | METH_FASTCALL | METH_KEYWORDS

Extension of METH_FASTCALL | METH_KEYWORDS supporting the defining class, that is, the class that contains the method in question. The defining class might be a superclass of Py_TYPE(self).

메서드는 PyCMethod 형이어야 하는데, self 뒤에 defining_class 인자가 추가된 METH_FASTCALL | METH_KEYWORDS와 같습니다.

Added in version 3.9.

METH_NOARGS

Methods without parameters don’t need to check whether arguments are given if they are listed with the METH_NOARGS flag. They need to be of type PyCFunction. The first parameter is typically named self and will hold a reference to the module or object instance. In all cases the second parameter will be NULL.

The function must have 2 parameters. Since the second parameter is unused, Py_UNUSED can be used to prevent a compiler warning.

METH_O

Methods with a single object argument can be listed with the METH_O flag, instead of invoking PyArg_ParseTuple() with a "O" argument. They have the type PyCFunction, with the self parameter, and a PyObject* parameter representing the single argument.

이 두 상수는 호출 규칙을 나타내는 데 사용되지 않고 클래스의 메서드와 함께 사용할 때 바인딩을 나타냅니다. 모듈에 정의된 함수에는 사용할 수 없습니다. 이러한 플래그 중 최대 하나를 주어진 메서드에 대해 설정할 수 있습니다.

METH_CLASS

메서드로 형의 인스턴스가 아닌 형 객체가 첫 번째 매개 변수로 전달됩니다. classmethod() 내장 함수를 사용할 때 만들어지는 것과 유사한 클래스 메서드(class methods)를 만드는 데 사용됩니다.

METH_STATIC

메서드로 형의 인스턴스가 아닌 NULL이 첫 번째 매개 변수로 전달됩니다. staticmethod() 내장 함수를 사용할 때 만들어지는 것과 유사한 정적 메서드(static methods)를 만드는 데 사용됩니다.

하나의 다른 상수는 같은 메서드 이름을 가진 다른 정의 대신 메서드가 로드되는지를 제어합니다.

METH_COEXIST

The method will be loaded in place of existing definitions. Without METH_COEXIST, the default is to skip repeated definitions. Since slot wrappers are loaded before the method table, the existence of a sq_contains slot, for example, would generate a wrapped method named __contains__() and preclude the loading of a corresponding PyCFunction with the same name. With the flag defined, the PyCFunction will be loaded in place of the wrapper object and will co-exist with the slot. This is helpful because calls to PyCFunctions are optimized more than wrapper object calls.

PyObject *PyCMethod_New(PyMethodDef *ml, PyObject *self, PyObject *module, PyTypeObject *cls)

Return value: New reference. Part of the Stable ABI since version 3.9.

Turn ml into a Python callable object. The caller must ensure that ml outlives the callable. Typically, ml is defined as a static variable.

The self parameter will be passed as the self argument to the C function in ml->ml_meth when invoked. self can be NULL.

The callable object’s __module__ attribute can be set from the given module argument. module should be a Python string, which will be used as name of the module the function is defined in. If unavailable, it can be set to None or NULL.

더 보기

function.__module__

The cls parameter will be passed as the defining_class argument to the C function. Must be set if METH_METHOD is set on ml->ml_flags.

Added in version 3.9.

PyObject *PyCFunction_NewEx(PyMethodDef *ml, PyObject *self, PyObject *module)

Return value: New reference. Part of the Stable ABI.

Equivalent to PyCMethod_New(ml, self, module, NULL).

PyObject *PyCFunction_New(PyMethodDef *ml, PyObject *self)

Return value: New reference. Part of the Stable ABI since version 3.4.

Equivalent to PyCMethod_New(ml, self, NULL, NULL).

확장형의 어트리뷰트 액세스

type PyMemberDef

Part of the Stable ABI (including all members).

Structure which describes an attribute of a type which corresponds to a C struct member. When defining a class, put a NULL-terminated array of these structures in the tp_members slot.

Its fields are, in order:

const char *name

Name of the member. A NULL value marks the end of a PyMemberDef[] array.

The string should be static, no copy is made of it.

int type

The type of the member in the C struct. See Member types for the possible values.

Py_ssize_t offset

The offset in bytes that the member is located on the type’s object struct.

int flags

Zero or more of the Member flags, combined using bitwise OR.

const char *doc

The docstring, or NULL. The string should be static, no copy is made of it. Typically, it is defined using PyDoc_STR.

By default (when flags is 0), members allow both read and write access. Use the Py_READONLY flag for read-only access. Certain types, like Py_T_STRING, imply Py_READONLY. Only Py_T_OBJECT_EX (and legacy T_OBJECT) members can be deleted.

For heap-allocated types (created using PyType_FromSpec() or similar), PyMemberDef may contain a definition for the special member "__vectorcalloffset__", corresponding to tp_vectorcall_offset in type objects. This member must be defined with Py_T_PYSSIZET, and either Py_READONLY or Py_READONLY | Py_RELATIVE_OFFSET. For example:

static PyMemberDef spam_type_members[] = {
    {"__vectorcalloffset__", Py_T_PYSSIZET,
     offsetof(Spam_object, vectorcall), Py_READONLY},
    {NULL}  /* Sentinel */
};

(You may need to #include <stddef.h> for offsetof().)

The legacy offsets tp_dictoffset and tp_weaklistoffset can be defined similarly using "__dictoffset__" and "__weaklistoffset__" members, but extensions are strongly encouraged to use Py_TPFLAGS_MANAGED_DICT and Py_TPFLAGS_MANAGED_WEAKREF instead.

버전 3.12에서 변경: PyMemberDef is always available. Previously, it required including "structmember.h".

버전 3.14에서 변경: Py_RELATIVE_OFFSET is now allowed for "__vectorcalloffset__", "__dictoffset__" and "__weaklistoffset__".

PyObject *PyMember_GetOne(const char *obj_addr, struct PyMemberDef *m)

Part of the Stable ABI.

Get an attribute belonging to the object at address obj_addr. The attribute is described by PyMemberDef m. Returns NULL on error.

버전 3.12에서 변경: PyMember_GetOne is always available. Previously, it required including "structmember.h".

int PyMember_SetOne(char *obj_addr, struct PyMemberDef *m, PyObject *o)

Part of the Stable ABI.

Set an attribute belonging to the object at address obj_addr to object o. The attribute to set is described by PyMemberDef m. Returns 0 if successful and a negative value on failure.

버전 3.12에서 변경: PyMember_SetOne is always available. Previously, it required including "structmember.h".

Member flags

The following flags can be used with PyMemberDef.flags:

Py_READONLY

Not writable.

Py_AUDIT_READ

Emit an object.__getattr__ audit event before reading.

Py_RELATIVE_OFFSET

Indicates that the offset of this PyMemberDef entry indicates an offset from the subclass-specific data, rather than from PyObject.

Can only be used as part of Py_tp_members slot when creating a class using negative basicsize. It is mandatory in that case.

This flag is only used in PyType_Slot. When setting tp_members during class creation, Python clears it and sets PyMemberDef.offset to the offset from the PyObject struct.

버전 3.10에서 변경: The RESTRICTED, READ_RESTRICTED and WRITE_RESTRICTED macros available with #include "structmember.h" are deprecated. READ_RESTRICTED and RESTRICTED are equivalent to Py_AUDIT_READ; WRITE_RESTRICTED does nothing.

버전 3.12에서 변경: The READONLY macro was renamed to Py_READONLY. The PY_AUDIT_READ macro was renamed with the Py_ prefix. The new names are now always available. Previously, these required #include "structmember.h". The header is still available and it provides the old names.

Member types

PyMemberDef.type can be one of the following macros corresponding to various C types. When the member is accessed in Python, it will be converted to the equivalent Python type. When it is set from Python, it will be converted back to the C type. If that is not possible, an exception such as TypeError or ValueError is raised.

Unless marked (D), attributes defined this way cannot be deleted using e.g. del or delattr().

매크로 이름

C 형

Python type

Py_T_BYTE

char

int

Py_T_SHORT

short

int

Py_T_INT

int

int

Py_T_LONG

long

int

Py_T_LONGLONG

long long

int

Py_T_UBYTE

unsigned char

int

Py_T_UINT

unsigned int

int

Py_T_USHORT

unsigned short

int

Py_T_ULONG

unsigned long

int

Py_T_ULONGLONG

unsigned long long

int

Py_T_PYSSIZET

Py_ssize_t

int

Py_T_FLOAT

float

float

Py_T_DOUBLE

double

float

Py_T_BOOL

char (written as 0 or 1)

bool

Py_T_STRING

const char* (*)

str (RO)

Py_T_STRING_INPLACE

const char[] (*)

str (RO)

Py_T_CHAR

char (0-127)

str (**)

Py_T_OBJECT_EX

PyObject*

object (D)

(*): Zero-terminated, UTF8-encoded C string. With Py_T_STRING the C representation is a pointer; with Py_T_STRING_INPLACE the string is stored directly in the structure.

(**): String of length 1. Only ASCII is accepted.

(RO): Implies Py_READONLY.

(D): Can be deleted, in which case the pointer is set to NULL. Reading a NULL pointer raises AttributeError.

Added in version 3.12: In previous versions, the macros were only available with #include "structmember.h" and were named without the Py_ prefix (e.g. as T_INT). The header is still available and contains the old names, along with the following deprecated types:

T_OBJECT

Like Py_T_OBJECT_EX, but NULL is converted to None. This results in surprising behavior in Python: deleting the attribute effectively sets it to None.

T_NONE

Always None. Must be used with Py_READONLY.

Defining Getters and Setters

type PyGetSetDef

Part of the Stable ABI (including all members).

형에 대한 프로퍼티 같은 액세스를 정의하는 구조체. PyTypeObject.tp_getset 슬롯에 대한 설명도 참조하십시오.

const char *name

어트리뷰트 이름

getter get

C function to get the attribute.

setter set

Optional C function to set or delete the attribute. If NULL, the attribute is read-only.

const char *doc

선택적 독스트링

void *closure

Optional user data pointer, providing additional data for getter and setter.

typedef PyObject *(*getter)(PyObject*, void*)

Part of the Stable ABI.

The get function takes one PyObject* parameter (the instance) and a user data pointer (the associated closure):

성공하면 새 참조를 반환하고, 실패하면 설정된 예외와 함께 NULL을 반환해야 합니다.

typedef int (*setter)(PyObject*, PyObject*, void*)

Part of the Stable ABI.

set functions take two PyObject* parameters (the instance and the value to be set) and a user data pointer (the associated closure):

어트리뷰트를 삭제해야 하는 경우 두 번째 매개 변수는 NULL입니다. 성공하면 0을, 실패하면 설정된 예외와 함께 -1을 반환해야 합니다.

형 객체

Perhaps one of the most important structures of the Python object system is the structure that defines a new type: the PyTypeObject structure. Type objects can be handled using any of the PyObject_* or PyType_* functions, but do not offer much that’s interesting to most Python applications. These objects are fundamental to how objects behave, so they are very important to the interpreter itself and to any extension module that implements new types.

형 객체는 대부분 표준형보다 상당히 큽니다. 크기가 큰 이유는 각 형 객체가 많은 수의 값을 저장하기 때문인데, 주로 C 함수 포인터이고 각기 형의 기능 중 작은 부분을 구현합니다. 이 섹션에서는 형 객체의 필드를 자세히 살펴봅니다. 필드는 구조체에서 나타나는 순서대로 설명됩니다.

다음의 간략 참조 외에도, 예 섹션은 PyTypeObject의 의미와 사용에 대한 통찰을 제공합니다.

간략 참조

“tp 슬롯”

PyTypeObject 슬롯 [1]

형

특수 메서드/어트리뷰트

정보 [2]

O

T

D

I

<R> tp_name

const char *

__name__

X

X

tp_basicsize

Py_ssize_t

X

X

X

tp_itemsize

Py_ssize_t

X

X

tp_dealloc

destructor

X

X

X

tp_vectorcall_offset

Py_ssize_t

X

X

(tp_getattr)

getattrfunc

__getattribute__, __getattr__

G

(tp_setattr)

setattrfunc

__setattr__, __delattr__

G

tp_as_async

PyAsyncMethods *

서브 슬롯

%

tp_repr

reprfunc

__repr__

X

X

X

tp_as_number

PyNumberMethods *

서브 슬롯

%

tp_as_sequence

PySequenceMethods *

서브 슬롯

%

tp_as_mapping

PyMappingMethods *

서브 슬롯

%

tp_hash

hashfunc

__hash__

X

G

tp_call

ternaryfunc

__call__

X

X

tp_str

reprfunc

__str__

X

X

tp_getattro

getattrofunc

__getattribute__, __getattr__

X

X

G

tp_setattro

setattrofunc

__setattr__, __delattr__

X

X

G

tp_as_buffer

PyBufferProcs *

%

tp_flags

unsigned long

X

X

?

tp_doc

const char *

__doc__

X

X

tp_traverse

traverseproc

X

G

tp_clear

inquiry

X

G

tp_richcompare

richcmpfunc

__lt__, __le__, __eq__, __ne__, __gt__, __ge__

X

G

(tp_weaklistoffset)

Py_ssize_t

X

?

tp_iter

getiterfunc

__iter__

X

tp_iternext

iternextfunc

__next__

X

tp_methods

PyMethodDef []

X

X

tp_members

PyMemberDef []

X

tp_getset

PyGetSetDef []

X

X

tp_base

PyTypeObject *

__base__

X

tp_dict

PyObject *

__dict__

?

tp_descr_get

descrgetfunc

__get__

X

tp_descr_set

descrsetfunc

__set__, __delete__

X

(tp_dictoffset)

Py_ssize_t

X

?

tp_init

initproc

__init__

X

X

X

tp_alloc

allocfunc

X

?

?

tp_new

newfunc

__new__

X

X

?

?

tp_free

freefunc

X

X

?

?

tp_is_gc

inquiry

X

X

<tp_bases>

PyObject *

__bases__

~

<tp_mro>

PyObject *

__mro__

~

[tp_cache]

PyObject *

[tp_subclasses]

void *

__subclasses__

[tp_weaklist]

PyObject *

(tp_del)

destructor

[tp_version_tag]

unsigned int

tp_finalize

destructor

__del__

X

tp_vectorcall

vectorcallfunc

[tp_watched]

unsigned char

[1]

(): A slot name in parentheses indicates it is (effectively) deprecated.

<>: Names in angle brackets should be initially set to NULL and treated as read-only.

[]: Names in square brackets are for internal use only.

<R> (as a prefix) means the field is required (must be non-NULL).

[2]

열:

“O”: set on PyBaseObject_Type

“T”: set on PyType_Type

“D”: 기본값 (슬롯이 NULL로 설정된 경우)

X - PyType_Ready sets this value if it is NULL
~ - PyType_Ready always sets this value (it should be NULL)
? - PyType_Ready may set this value depending on other slots

Also see the inheritance column ("I").

“I”: 상속

X - type slot is inherited via *PyType_Ready* if defined with a *NULL* value
% - the slots of the sub-struct are inherited individually
G - inherited, but only in combination with other slots; see the slot's description
? - it's complicated; see the slot's description

일부 슬롯은 일반 어트리뷰트 조회 체인을 통해 효과적으로 상속됨에 유의하십시오.

서브 슬롯

슬롯

형

특수 메서드

am_await

unaryfunc

__await__

am_aiter

unaryfunc

__aiter__

am_anext

unaryfunc

__anext__

am_send

sendfunc

nb_add

binaryfunc

__add__ __radd__

nb_inplace_add

binaryfunc

__iadd__

nb_subtract

binaryfunc

__sub__ __rsub__

nb_inplace_subtract

binaryfunc

__isub__

nb_multiply

binaryfunc

__mul__ __rmul__

nb_inplace_multiply

binaryfunc

__imul__

nb_remainder

binaryfunc

__mod__ __rmod__

nb_inplace_remainder

binaryfunc

__imod__

nb_divmod

binaryfunc

__divmod__ __rdivmod__

nb_power

ternaryfunc

__pow__ __rpow__

nb_inplace_power

ternaryfunc

__ipow__

nb_negative

unaryfunc

__neg__

nb_positive

unaryfunc

__pos__

nb_absolute

unaryfunc

__abs__

nb_bool

inquiry

__bool__

nb_invert

unaryfunc

__invert__

nb_lshift

binaryfunc

__lshift__ __rlshift__

nb_inplace_lshift

binaryfunc

__ilshift__

nb_rshift

binaryfunc

__rshift__ __rrshift__

nb_inplace_rshift

binaryfunc

__irshift__

nb_and

binaryfunc

__and__ __rand__

nb_inplace_and

binaryfunc

__iand__

nb_xor

binaryfunc

__xor__ __rxor__

nb_inplace_xor

binaryfunc

__ixor__

nb_or

binaryfunc

__or__ __ror__

nb_inplace_or

binaryfunc

__ior__

nb_int

unaryfunc

__int__

nb_reserved

void *

nb_float

unaryfunc

__float__

nb_floor_divide

binaryfunc

__floordiv__

nb_inplace_floor_divide

binaryfunc

__ifloordiv__

nb_true_divide

binaryfunc

__truediv__

nb_inplace_true_divide

binaryfunc

__itruediv__

nb_index

unaryfunc

__index__

nb_matrix_multiply

binaryfunc

__matmul__ __rmatmul__

nb_inplace_matrix_multiply

binaryfunc

__imatmul__

mp_length

lenfunc

__len__

mp_subscript

binaryfunc

__getitem__

mp_ass_subscript

objobjargproc

__setitem__, __delitem__

sq_length

lenfunc

__len__

sq_concat

binaryfunc

__add__

sq_repeat

ssizeargfunc

__mul__

sq_item

ssizeargfunc

__getitem__

sq_ass_item

ssizeobjargproc

__setitem__ __delitem__

sq_contains

objobjproc

__contains__

sq_inplace_concat

binaryfunc

__iadd__

sq_inplace_repeat

ssizeargfunc

__imul__

bf_getbuffer

getbufferproc()

bf_releasebuffer

releasebufferproc()

슬롯 typedef

typedef

매개 변수 형

반환형

allocfunc

PyTypeObject *

Py_ssize_t

PyObject *

destructor

PyObject *

void

freefunc

void *

void

traverseproc

PyObject *

visitproc

void *

int

newfunc

PyTypeObject *

PyObject *

PyObject *

PyObject *

initproc

PyObject *

PyObject *

PyObject *

int

reprfunc

PyObject *

PyObject *

getattrfunc

PyObject *

const char *

PyObject *

setattrfunc

PyObject *

const char *

PyObject *

int

getattrofunc

PyObject *

PyObject *

PyObject *

setattrofunc

PyObject *

PyObject *

PyObject *

int

descrgetfunc

PyObject *

PyObject *

PyObject *

PyObject *

descrsetfunc

PyObject *

PyObject *

PyObject *

int

hashfunc

PyObject *

Py_hash_t

richcmpfunc

PyObject *

PyObject *

int

PyObject *

getiterfunc

PyObject *

PyObject *

iternextfunc

PyObject *

PyObject *

lenfunc

PyObject *

Py_ssize_t

getbufferproc

PyObject *

Py_buffer *

int

int

releasebufferproc

PyObject *

Py_buffer *

void

inquiry

PyObject *

int

unaryfunc

PyObject *

PyObject *

binaryfunc

PyObject *

PyObject *

PyObject *

ternaryfunc

PyObject *

PyObject *

PyObject *

PyObject *

ssizeargfunc

PyObject *

Py_ssize_t

PyObject *

ssizeobjargproc

PyObject *

Py_ssize_t

PyObject *

int

objobjproc

PyObject *

PyObject *

int

objobjargproc

PyObject *

PyObject *

PyObject *

int

자세한 내용은 아래 슬롯 형 typedef를 참조하십시오.

PyTypeObject 정의

PyTypeObject의 구조체 정의는 Include/object.h에서 찾을 수 있습니다. 참조 편의를 위해, 다음에 정의를 반복합니다:

typedef struct _typeobject {
    PyObject_VAR_HEAD
    const char *tp_name; /* For printing, in format "<module>.<name>" */
    Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

    /* Methods to implement standard operations */

    destructor tp_dealloc;
    Py_ssize_t tp_vectorcall_offset;
    getattrfunc tp_getattr;
    setattrfunc tp_setattr;
    PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
                                    or tp_reserved (Python 3) */
    reprfunc tp_repr;

    /* Method suites for standard classes */

    PyNumberMethods *tp_as_number;
    PySequenceMethods *tp_as_sequence;
    PyMappingMethods *tp_as_mapping;

    /* More standard operations (here for binary compatibility) */

    hashfunc tp_hash;
    ternaryfunc tp_call;
    reprfunc tp_str;
    getattrofunc tp_getattro;
    setattrofunc tp_setattro;

    /* Functions to access object as input/output buffer */
    PyBufferProcs *tp_as_buffer;

    /* Flags to define presence of optional/expanded features */
    unsigned long tp_flags;

    const char *tp_doc; /* Documentation string */

    /* Assigned meaning in release 2.0 */
    /* call function for all accessible objects */
    traverseproc tp_traverse;

    /* delete references to contained objects */
    inquiry tp_clear;

    /* Assigned meaning in release 2.1 */
    /* rich comparisons */
    richcmpfunc tp_richcompare;

    /* weak reference enabler */
    Py_ssize_t tp_weaklistoffset;

    /* Iterators */
    getiterfunc tp_iter;
    iternextfunc tp_iternext;

    /* Attribute descriptor and subclassing stuff */
    struct PyMethodDef *tp_methods;
    struct PyMemberDef *tp_members;
    struct PyGetSetDef *tp_getset;
    // Strong reference on a heap type, borrowed reference on a static type
    struct _typeobject *tp_base;
    PyObject *tp_dict;
    descrgetfunc tp_descr_get;
    descrsetfunc tp_descr_set;
    Py_ssize_t tp_dictoffset;
    initproc tp_init;
    allocfunc tp_alloc;
    newfunc tp_new;
    freefunc tp_free; /* Low-level free-memory routine */
    inquiry tp_is_gc; /* For PyObject_IS_GC */
    PyObject *tp_bases;
    PyObject *tp_mro; /* method resolution order */
    PyObject *tp_cache;
    PyObject *tp_subclasses;
    PyObject *tp_weaklist;
    destructor tp_del;

    /* Type attribute cache version tag. Added in version 2.6 */
    unsigned int tp_version_tag;

    destructor tp_finalize;
    vectorcallfunc tp_vectorcall;

    /* bitset of which type-watchers care about this type */
    unsigned char tp_watched;
} PyTypeObject;

PyObject 슬롯

The type object structure extends the PyVarObject structure. The ob_size field is used for dynamic types (created by type_new(), usually called from a class statement). Note that PyType_Type (the metatype) initializes tp_itemsize, which means that its instances (i.e. type objects) must have the ob_size field.

Py_ssize_t PyObject.ob_refcnt

Part of the Stable ABI.

This is the type object’s reference count, initialized to 1 by the PyObject_HEAD_INIT macro. Note that for statically allocated type objects, the type’s instances (objects whose ob_type points back to the type) do not count as references. But for dynamically allocated type objects, the instances do count as references.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다.

PyTypeObject *PyObject.ob_type

Part of the Stable ABI.

이것은 형의 형, 즉 메타 형(metatype)입니다. PyObject_HEAD_INIT 매크로에 대한 인자로 초기화되며, 값은 일반적으로 &PyType_Type이어야 합니다. 그러나, (적어도) 윈도우에서 사용 가능해야 하는 동적으로 로드 가능한 확장 모듈의 경우, 컴파일러는 유효한 초기화자가 아니라고 불평합니다. 따라서, 규칙은 NULL을 PyObject_HEAD_INIT 매크로로 전달하고, 다른 작업을 수행하기 전에 모듈의 초기화 함수 시작에서 필드를 명시적으로 초기화하는 것입니다. 이것은 일반적으로 다음과 같이 수행됩니다:

Foo_Type.ob_type = &PyType_Type;

This should be done before any instances of the type are created. PyType_Ready() checks if ob_type is NULL, and if so, initializes it to the ob_type field of the base class. PyType_Ready() will not change this field if it is non-zero.

계승:

이 필드는 서브 형으로 상속됩니다.

PyVarObject 슬롯

Py_ssize_t PyVarObject.ob_size

Part of the Stable ABI.

For statically allocated type objects, this should be initialized to zero. For dynamically allocated type objects, this field has a special internal meaning.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다.

PyTypeObject 슬롯

Each slot has a section describing inheritance. If PyType_Ready() may set a value when the field is set to NULL then there will also be a “Default” section. (Note that many fields set on PyBaseObject_Type and PyType_Type effectively act as defaults.)

const char *PyTypeObject.tp_name

Pointer to a NUL-terminated string containing the name of the type. For types that are accessible as module globals, the string should be the full module name, followed by a dot, followed by the type name; for built-in types, it should be just the type name. If the module is a submodule of a package, the full package name is part of the full module name. For example, a type named T defined in module M in subpackage Q in package P should have the tp_name initializer "P.Q.M.T".

For dynamically allocated type objects, this should just be the type name, and the module name explicitly stored in the type dict as the value for key '__module__'.

For statically allocated type objects, the tp_name field should contain a dot. Everything before the last dot is made accessible as the __module__ attribute, and everything after the last dot is made accessible as the __name__ attribute.

If no dot is present, the entire tp_name field is made accessible as the __name__ attribute, and the __module__ attribute is undefined (unless explicitly set in the dictionary, as explained above). This means your type will be impossible to pickle. Additionally, it will not be listed in module documentations created with pydoc.

이 필드는 NULL이 아니어야 합니다. PyTypeObject()에서 유일하게 필요한 필드입니다 (잠재적인 tp_itemsize를 제외하고).

계승:

이 필드는 서브 형에 의해 상속되지 않습니다.

Py_ssize_t PyTypeObject.tp_basicsize

Py_ssize_t PyTypeObject.tp_itemsize

이 필드를 사용하면 형 인스턴스의 크기를 바이트 단위로 계산할 수 있습니다.

두 가지 종류의 형이 있습니다: 고정 길이 인스턴스의 형은 0 tp_itemsize 필드를 갖고, 가변 길이 인스턴스의 형에는 0이 아닌 tp_itemsize 필드가 있습니다. 고정 길이 인스턴스의 형의 경우, 모든 인스턴스는 tp_basicsize로 지정되는 같은 크기를 갖습니다.

For a type with variable-length instances, the instances must have an ob_size field, and the instance size is tp_basicsize plus N times tp_itemsize, where N is the “length” of the object. The value of N is typically stored in the instance’s ob_size field. There are exceptions: for example, ints use a negative ob_size to indicate a negative number, and N is abs(ob_size) there. Also, the presence of an ob_size field in the instance layout doesn’t mean that the instance structure is variable-length (for example, the structure for the list type has fixed-length instances, yet those instances have a meaningful ob_size field).

The basic size includes the fields in the instance declared by the macro PyObject_HEAD or PyObject_VAR_HEAD (whichever is used to declare the instance struct) and this in turn includes the _ob_prev and _ob_next fields if they are present. This means that the only correct way to get an initializer for the tp_basicsize is to use the sizeof operator on the struct used to declare the instance layout. The basic size does not include the GC header size.

정렬(alignment)에 대한 참고 사항: 가변 길이 항목에 특정 정렬이 필요하면, tp_basicsize 값에서 고려되어야 합니다. 예: 형이 double 배열을 구현하는 형을 가정합시다. tp_itemsize는 sizeof(double)입니다. tp_basicsize가 sizeof(double)의 배수가 되도록 하는 것은 프로그래머의 책임입니다 (이것이 double의 정렬 요구 사항이라고 가정합니다).

가변 길이 인스턴스가 있는 모든 형의 경우, 이 필드는 NULL이 아니어야 합니다.

계승:

이 필드는 서브 형에 의해 별도로 상속됩니다. 베이스형에 0이 아닌 tp_itemsize가 있으면, 일반적으로 서브 형에서 tp_itemsize를 다른 0이 아닌 값으로 설정하는 것은 안전하지 않습니다 (베이스형의 구현에 따라 다르기는 합니다).

destructor PyTypeObject.tp_dealloc

인스턴스 파괴자(destructor) 함수에 대한 포인터. (싱글톤 None과 Ellipsis의 경우처럼) 형이 해당 인스턴스가 할당 해제되지 않도록 보장하지 않는 한, 이 함수를 정의해야 합니다. 함수 서명은 다음과 같습니다:

void tp_dealloc(PyObject *self);

The destructor function is called by the Py_DECREF() and Py_XDECREF() macros when the new reference count is zero. At this point, the instance is still in existence, but there are no references to it. The destructor function should free all references which the instance owns, free all memory buffers owned by the instance (using the freeing function corresponding to the allocation function used to allocate the buffer), and call the type’s tp_free function. If the type is not subtypable (doesn’t have the Py_TPFLAGS_BASETYPE flag bit set), it is permissible to call the object deallocator directly instead of via tp_free. The object deallocator should be the one used to allocate the instance; this is normally PyObject_Free() if the instance was allocated using PyObject_New or PyObject_NewVar, or PyObject_GC_Del() if the instance was allocated using PyObject_GC_New or PyObject_GC_NewVar.

If the type supports garbage collection (has the Py_TPFLAGS_HAVE_GC flag bit set), the destructor should call PyObject_GC_UnTrack() before clearing any member fields.

static void foo_dealloc(foo_object *self) {
    PyObject_GC_UnTrack(self);
    Py_CLEAR(self->ref);
    Py_TYPE(self)->tp_free((PyObject *)self);
}

Finally, if the type is heap allocated (Py_TPFLAGS_HEAPTYPE), the deallocator should release the owned reference to its type object (via Py_DECREF()) after calling the type deallocator. In order to avoid dangling pointers, the recommended way to achieve this is:

static void foo_dealloc(foo_object *self) {
    PyTypeObject *tp = Py_TYPE(self);
    // free references and buffers here
    tp->tp_free(self);
    Py_DECREF(tp);
}

경고

In a garbage collected Python, tp_dealloc may be called from any Python thread, not just the thread which created the object (if the object becomes part of a refcount cycle, that cycle might be collected by a garbage collection on any thread). This is not a problem for Python API calls, since the thread on which tp_dealloc is called will own the Global Interpreter Lock (GIL). However, if the object being destroyed in turn destroys objects from some other C or C++ library, care should be taken to ensure that destroying those objects on the thread which called tp_dealloc will not violate any assumptions of the library.

계승:

이 필드는 서브 형으로 상속됩니다.

Py_ssize_t PyTypeObject.tp_vectorcall_offset

간단한 tp_call의 더 효율적인 대안인 벡터콜(vectorcall) 프로토콜을 사용하여 객체를 호출하는 것을 구현하는 인스턴스별 함수에 대한 선택적 오프셋입니다.

This field is only used if the flag Py_TPFLAGS_HAVE_VECTORCALL is set. If so, this must be a positive integer containing the offset in the instance of a vectorcallfunc pointer.

The vectorcallfunc pointer may be NULL, in which case the instance behaves as if Py_TPFLAGS_HAVE_VECTORCALL was not set: calling the instance falls back to tp_call.

Py_TPFLAGS_HAVE_VECTORCALL을 설정하는 모든 클래스는 tp_call도 설정해야 하고, 해당 동작이 vectorcallfunc 함수와 일관되도록 만들어야 합니다. tp_call을 PyVectorcall_Call()로 설정하면 됩니다:

버전 3.8에서 변경: 버전 3.8 이전에는, 이 슬롯의 이름이 tp_print였습니다. 파이썬 2.x에서는, 파일로 인쇄하는 데 사용되었습니다. 파이썬 3.0에서 3.7까지는, 사용되지 않았습니다.

버전 3.12에서 변경: Before version 3.12, it was not recommended for mutable heap types to implement the vectorcall protocol. When a user sets __call__ in Python code, only tp_call is updated, likely making it inconsistent with the vectorcall function. Since 3.12, setting __call__ will disable vectorcall optimization by clearing the Py_TPFLAGS_HAVE_VECTORCALL flag.

계승:

This field is always inherited. However, the Py_TPFLAGS_HAVE_VECTORCALL flag is not always inherited. If it’s not set, then the subclass won’t use vectorcall, except when PyVectorcall_Call() is explicitly called.

getattrfunc PyTypeObject.tp_getattr

get-attribute-string 함수에 대한 선택적 포인터.

이 필드는 폐지되었습니다. 정의될 때, tp_getattro 함수와 같게 작동하지만, 어트리뷰트 이름을 제공하기 위해 파이썬 문자열 객체 대신 C 문자열을 받아들이는 함수를 가리켜야 합니다.

계승:

Group: tp_getattr, tp_getattro

이 필드는 tp_getattro와 함께 서브 형에 의해 상속됩니다: 서브 형은 서브 형의 tp_getattr과 tp_getattro가 모두 NULL일 때 베이스형에서 tp_getattr과 tp_getattro를 모두 상속합니다.

setattrfunc PyTypeObject.tp_setattr

어트리뷰트 설정과 삭제를 위한 함수에 대한 선택적 포인터.

이 필드는 폐지되었습니다. 정의될 때, tp_setattro 함수와 같게 작동하지만, 어트리뷰트 이름을 제공하기 위해 파이썬 문자열 객체 대신 C 문자열을 받아들이는 함수를 가리켜야 합니다.

계승:

Group: tp_setattr, tp_setattro

이 필드는 tp_setattro와 함께 서브 형에 의해 상속됩니다. 서브 형은 서브 형의 tp_setattr과 tp_setattro가 모두 NULL일 때 베이스형에서 tp_setattr과 tp_setattro를 모두 상속합니다.

PyAsyncMethods *PyTypeObject.tp_as_async

C 수준에서 어웨이터블과 비동기 이터레이터 프로토콜을 구현하는 객체에만 관련된 필드를 포함하는 추가 구조체에 대한 포인터. 자세한 내용은 비동기 객체 구조체를 참조하십시오.

Added in version 3.5: 이전에는 tp_compare와 tp_reserved라고 했습니다.

계승:

tp_as_async 필드는 상속되지 않지만, 포함된 필드는 개별적으로 상속됩니다.

reprfunc PyTypeObject.tp_repr

내장 함수 repr()을 구현하는 함수에 대한 선택적 포인터.

서명은 PyObject_Repr()과 같습니다:

PyObject *tp_repr(PyObject *self);

함수는 문자열이나 유니코드 객체를 반환해야 합니다. 이상적으로, 이 함수는 eval()에 전달될 때 적합한 환경이 주어지면 같은 값을 가진 객체를 반환하는 문자열을 반환해야 합니다. 이것이 가능하지 않으면, '<'로 시작하고 '>'로 끝나는 문자열을 반환해야 하는데, 이 문자열에서 객체의 형과 값을 모두 추론할 수 있어야 합니다.

계승:

이 필드는 서브 형으로 상속됩니다.

기본값:

이 필드를 설정하지 않으면, <%s object at %p> 형식의 문자열이 반환됩니다. 여기서 %s는 형 이름으로, %p는 객체의 메모리 주소로 치환됩니다.

PyNumberMethods *PyTypeObject.tp_as_number

숫자 프로토콜을 구현하는 객체에만 관련된 필드를 포함하는 추가 구조체에 대한 포인터. 이 필드는 숫자 객체 구조체에서 설명합니다.

계승:

tp_as_number 필드는 상속되지 않지만, 포함된 필드는 개별적으로 상속됩니다.

PySequenceMethods *PyTypeObject.tp_as_sequence

시퀀스 프로토콜을 구현하는 객체에만 관련된 필드를 포함하는 추가 구조체에 대한 포인터. 이 필드는 시퀀스 객체 구조체에서 설명합니다.

계승:

tp_as_sequence 필드는 상속되지 않지만, 포함된 필드는 개별적으로 상속됩니다.

PyMappingMethods *PyTypeObject.tp_as_mapping

매핑 프로토콜을 구현하는 객체에만 관련된 필드를 포함하는 추가 구조체에 대한 포인터. 이 필드는 매핑 객체 구조체에서 설명합니다.

계승:

tp_as_mapping 필드는 상속되지 않지만, 포함된 필드는 개별적으로 상속됩니다.

hashfunc PyTypeObject.tp_hash

내장 함수 hash()를 구현하는 함수에 대한 선택적 포인터.

서명은 PyObject_Hash()와 같습니다:

Py_hash_t tp_hash(PyObject *);

-1 값은 정상적인 반환 값으로 반환되지 않아야 합니다; 해시값을 계산하는 동안 에러가 발생하면 함수는 예외를 설정하고 -1을 반환해야 합니다.

When this field is not set (and tp_richcompare is not set), an attempt to take the hash of the object raises TypeError. This is the same as setting it to PyObject_HashNotImplemented().

이 필드는 부모 형에서 해시 메서드의 상속을 차단하기 위해 PyObject_HashNotImplemented()로 명시적으로 설정할 수 있습니다. 이것은 파이썬 수준에서의 __hash__ = None과 동등한 것으로 해석되어, isinstance(o, collections.Hashable)이 False를 올바르게 반환하게 합니다. 반대의 경우도 마찬가지입니다 - 파이썬 수준의 클래스에서 __hash__ = None을 설정하면 tp_hash 슬롯이 PyObject_HashNotImplemented()로 설정됩니다.

계승:

Group: tp_hash, tp_richcompare

이 필드는 tp_richcompare와 함께 서브 형에 의해 상속됩니다: 서브 형의 tp_richcompare와 tp_hash가 모두 NULL일 때, 서브 형은 tp_richcompare와 tp_hash를 모두 상속합니다.

기본값:

PyBaseObject_Type uses PyObject_GenericHash().

ternaryfunc PyTypeObject.tp_call

객체 호출을 구현하는 함수에 대한 선택적 포인터. 객체가 콜러블이 아니면 NULL이어야 합니다. 서명은 PyObject_Call()과 같습니다:

PyObject *tp_call(PyObject *self, PyObject *args, PyObject *kwargs);

계승:

이 필드는 서브 형으로 상속됩니다.

reprfunc PyTypeObject.tp_str

내장 연산 str()을 구현하는 함수에 대한 선택적 포인터. (str는 이제 형이며, str()은 그 형의 생성자를 호출함에 유의하십시오. 이 생성자는 PyObject_Str()를 호출하여 실제 작업을 수행하고, PyObject_Str()은 이 처리기를 호출합니다.)

서명은 PyObject_Str()과 같습니다:

PyObject *tp_str(PyObject *self);

함수는 문자열이나 유니코드 객체를 반환해야 합니다. 다른 것 중에서도, print() 함수에 의해 사용될 표현이기 때문에, 객체의 “친숙한” 문자열 표현이어야 합니다.

계승:

이 필드는 서브 형으로 상속됩니다.

기본값:

이 필드를 설정하지 않으면, 문자열 표현을 반환하기 위해 PyObject_Repr()이 호출됩니다.

getattrofunc PyTypeObject.tp_getattro

어트리뷰트 읽기(get-attribute) 함수에 대한 선택적 포인터.

서명은 PyObject_GetAttr()과 같습니다:

PyObject *tp_getattro(PyObject *self, PyObject *attr);

일반적으로 이 필드를 PyObject_GenericGetAttr()로 설정하는 것이 편리합니다, 객체 어트리뷰트를 찾는 일반적인 방법을 구현합니다.

계승:

Group: tp_getattr, tp_getattro

이 필드는 tp_getattr과 함께 서브 형에 의해 상속됩니다: 서브 형의 tp_getattr과 tp_getattro가 모두 NULL일 때 서브 형은 베이스형에서 tp_getattr과 tp_getattro를 모두 상속합니다.

기본값:

PyBaseObject_Type uses PyObject_GenericGetAttr().

setattrofunc PyTypeObject.tp_setattro

어트리뷰트 설정과 삭제를 위한 함수에 대한 선택적 포인터.

서명은 PyObject_SetAttr()과 같습니다:

int tp_setattro(PyObject *self, PyObject *attr, PyObject *value);

또한, value를 NULL로 설정하여 어트리뷰트를 삭제하는 것을 반드시 지원해야 합니다. 일반적으로 이 필드를 PyObject_GenericSetAttr()로 설정하는 것이 편리합니다, 객체 어트리뷰트를 설정하는 일반적인 방법을 구현합니다.

계승:

Group: tp_setattr, tp_setattro

이 필드는 tp_setattr과 함께 서브 형에 의해 상속됩니다: 서브 형의 tp_setattr과 tp_setattro가 모두 NULL일 때, 서브 형은 베이스형에서 tp_setattr과 tp_setattro를 모두 상속합니다.

기본값:

PyBaseObject_Type uses PyObject_GenericSetAttr().

PyBufferProcs *PyTypeObject.tp_as_buffer

버퍼 인터페이스를 구현하는 객체에만 관련된 필드를 포함하는 추가 구조체에 대한 포인터. 이 필드는 버퍼 객체 구조체에서 설명합니다.

계승:

tp_as_buffer 필드는 상속되지 않지만, 포함된 필드는 개별적으로 상속됩니다.

unsigned long PyTypeObject.tp_flags

이 필드는 다양한 플래그의 비트 마스크입니다. 일부 플래그는 특정 상황에 대한 변형 의미론을 나타냅니다; 다른 것들은 역사적으로 항상 존재하지는 않았던 형 객체(또는 tp_as_number, tp_as_sequence, tp_as_mapping 및 tp_as_buffer를 통해 참조되는 확장 구조체)의 특정 필드가 유효함을 나타내는 데 사용됩니다; 이러한 플래그 비트가 없으면, 이것이 보호하는 형 필드에 액세스하지 말아야 하며 대신 0이나 NULL 값을 갖는 것으로 간주해야 합니다.

계승:

Inheritance of this field is complicated. Most flag bits are inherited individually, i.e. if the base type has a flag bit set, the subtype inherits this flag bit. The flag bits that pertain to extension structures are strictly inherited if the extension structure is inherited, i.e. the base type’s value of the flag bit is copied into the subtype together with a pointer to the extension structure. The Py_TPFLAGS_HAVE_GC flag bit is inherited together with the tp_traverse and tp_clear fields, i.e. if the Py_TPFLAGS_HAVE_GC flag bit is clear in the subtype and the tp_traverse and tp_clear fields in the subtype exist and have NULL values. .. XXX are most flag bits really inherited individually?

기본값:

PyBaseObject_Type uses Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE.

비트 마스크:

다음 비트 마스크가 현재 정의되어 있습니다; 이들은 | 연산자로 함께 OR 하여 tp_flags 필드의 값을 형성할 수 있습니다. 매크로 PyType_HasFeature()는 형과 플래그 값 tp와 f를 취하고 tp->tp_flags & f가 0이 아닌지 확인합니다.

Py_TPFLAGS_HEAPTYPE

This bit is set when the type object itself is allocated on the heap, for example, types created dynamically using PyType_FromSpec(). In this case, the ob_type field of its instances is considered a reference to the type, and the type object is INCREF’ed when a new instance is created, and DECREF’ed when an instance is destroyed (this does not apply to instances of subtypes; only the type referenced by the instance’s ob_type gets INCREF’ed or DECREF’ed). Heap types should also support garbage collection as they can form a reference cycle with their own module object.

계승:

???

Py_TPFLAGS_BASETYPE

이 비트는 형을 다른 형의 베이스형으로 사용할 수 있을 때 설정됩니다. 이 비트가 설정되지 않으면 이 형으로 서브 형을 만들 수 없습니다 (Java의 “final” 클래스와 유사합니다).

계승:

???

Py_TPFLAGS_READY

이 비트는 PyType_Ready()에 의해 형 객체가 완전히 초기화될 때 설정됩니다.

계승:

???

Py_TPFLAGS_READYING

이 비트는 PyType_Ready()가 형 객체를 초기화하는 동안 설정됩니다.

계승:

???

Py_TPFLAGS_HAVE_GC

This bit is set when the object supports garbage collection. If this bit is set, instances must be created using PyObject_GC_New and destroyed using PyObject_GC_Del(). More information in section 순환 가비지 수집 지원. This bit also implies that the GC-related fields tp_traverse and tp_clear are present in the type object.

계승:

Group: Py_TPFLAGS_HAVE_GC, tp_traverse, tp_clear

The Py_TPFLAGS_HAVE_GC flag bit is inherited together with the tp_traverse and tp_clear fields, i.e. if the Py_TPFLAGS_HAVE_GC flag bit is clear in the subtype and the tp_traverse and tp_clear fields in the subtype exist and have NULL values.

Py_TPFLAGS_DEFAULT

This is a bitmask of all the bits that pertain to the existence of certain fields in the type object and its extension structures. Currently, it includes the following bits: Py_TPFLAGS_HAVE_STACKLESS_EXTENSION.

계승:

???

Py_TPFLAGS_METHOD_DESCRIPTOR

이 비트는 객체가 연결되지 않은 메서드(unbound method)처럼 동작함을 나타냅니다.

이 플래그가 type(meth)에 설정되면:

meth.__get__(obj, cls)(*args, **kwds)(obj가 None이 아닐 때)는 meth(obj, *args, **kwds)와 동등해야 합니다.

meth.__get__(None, cls)(*args, **kwds)는 meth(*args, **kwds)와 동등해야 합니다.

이 플래그는 obj.meth()와 같은 일반적인 메서드 호출에 대한 최적화를 가능하게 합니다: obj.meth에 대한 임시 “연결된 메서드(bound method)” 객체를 만들지 않습니다.

Added in version 3.8.

계승:

This flag is never inherited by types without the Py_TPFLAGS_IMMUTABLETYPE flag set. For extension types, it is inherited whenever tp_descr_get is inherited.

Py_TPFLAGS_MANAGED_DICT

This bit indicates that instances of the class have a ~object.__dict__ attribute, and that the space for the dictionary is managed by the VM.

If this flag is set, Py_TPFLAGS_HAVE_GC should also be set.

The type traverse function must call PyObject_VisitManagedDict() and its clear function must call PyObject_ClearManagedDict().

Added in version 3.12.

계승:

This flag is inherited unless the tp_dictoffset field is set in a superclass.

Py_TPFLAGS_MANAGED_WEAKREF

This bit indicates that instances of the class should be weakly referenceable.

Added in version 3.12.

계승:

This flag is inherited unless the tp_weaklistoffset field is set in a superclass.

Py_TPFLAGS_ITEMS_AT_END

Only usable with variable-size types, i.e. ones with non-zero tp_itemsize.

Indicates that the variable-sized portion of an instance of this type is at the end of the instance’s memory area, at an offset of Py_TYPE(obj)->tp_basicsize (which may be different in each subclass).

When setting this flag, be sure that all superclasses either use this memory layout, or are not variable-sized. Python does not check this.

Added in version 3.12.

계승:

This flag is inherited.

Py_TPFLAGS_LONG_SUBCLASS

Py_TPFLAGS_LIST_SUBCLASS

Py_TPFLAGS_TUPLE_SUBCLASS

Py_TPFLAGS_BYTES_SUBCLASS

Py_TPFLAGS_UNICODE_SUBCLASS

Py_TPFLAGS_DICT_SUBCLASS

Py_TPFLAGS_BASE_EXC_SUBCLASS

Py_TPFLAGS_TYPE_SUBCLASS

이 플래그는 PyLong_Check() 와 같은 함수에서 형이 내장형의 서브 클래스인지 신속하게 판별하는 데 사용됩니다; 이러한 특정 검사는 PyObject_IsInstance()와 같은 일반 검사보다 빠릅니다. 내장에서 상속된 사용자 정의 형은 tp_flags를 적절하게 설정해야 합니다, 그렇지 않으면 그러한 형과 상호 작용하는 코드가 사용되는 검사의 유형에 따라 다르게 작동합니다.

Py_TPFLAGS_HAVE_FINALIZE

이 비트는 tp_finalize 슬롯이 형 구조체에 있을 때 설정됩니다.

Added in version 3.4.

버전 3.8부터 폐지됨: 인터프리터는 tp_finalize 슬롯이 항상 형 구조체에 있다고 가정하기 때문에, 이 플래그는 더는 필요하지 않습니다.

Py_TPFLAGS_HAVE_VECTORCALL

이 비트는 클래스가 벡터콜 프로토콜을 구현할 때 설정됩니다. 자세한 내용은 tp_vectorcall_offset을 참조하십시오.

계승:

This bit is inherited if tp_call is also inherited.

Added in version 3.9.

버전 3.12에서 변경: This flag is now removed from a class when the class’s __call__() method is reassigned.

This flag can now be inherited by mutable classes.

Py_TPFLAGS_IMMUTABLETYPE

This bit is set for type objects that are immutable: type attributes cannot be set nor deleted.

PyType_Ready() automatically applies this flag to static types.

계승:

This flag is not inherited.

Added in version 3.10.

Py_TPFLAGS_DISALLOW_INSTANTIATION

Disallow creating instances of the type: set tp_new to NULL and don’t create the __new__ key in the type dictionary.

The flag must be set before creating the type, not after. For example, it must be set before PyType_Ready() is called on the type.

The flag is set automatically on static types if tp_base is NULL or &PyBaseObject_Type and tp_new is NULL.

계승:

This flag is not inherited. However, subclasses will not be instantiable unless they provide a non-NULL tp_new (which is only possible via the C API).

참고

To disallow instantiating a class directly but allow instantiating its subclasses (e.g. for an abstract base class), do not use this flag. Instead, make tp_new only succeed for subclasses.

Added in version 3.10.

Py_TPFLAGS_MAPPING

This bit indicates that instances of the class may match mapping patterns when used as the subject of a match block. It is automatically set when registering or subclassing collections.abc.Mapping, and unset when registering collections.abc.Sequence.

참고

Py_TPFLAGS_MAPPING and Py_TPFLAGS_SEQUENCE are mutually exclusive; it is an error to enable both flags simultaneously.

계승:

This flag is inherited by types that do not already set Py_TPFLAGS_SEQUENCE.

더 보기

PEP 634 [https://peps.python.org/pep-0634/] – Structural Pattern Matching: Specification

Added in version 3.10.

Py_TPFLAGS_SEQUENCE

This bit indicates that instances of the class may match sequence patterns when used as the subject of a match block. It is automatically set when registering or subclassing collections.abc.Sequence, and unset when registering collections.abc.Mapping.

참고

Py_TPFLAGS_MAPPING and Py_TPFLAGS_SEQUENCE are mutually exclusive; it is an error to enable both flags simultaneously.

계승:

This flag is inherited by types that do not already set Py_TPFLAGS_MAPPING.

더 보기

PEP 634 [https://peps.python.org/pep-0634/] – Structural Pattern Matching: Specification

Added in version 3.10.

Py_TPFLAGS_VALID_VERSION_TAG

Internal. Do not set or unset this flag. To indicate that a class has changed call PyType_Modified()

경고

This flag is present in header files, but is not be used. It will be removed in a future version of CPython

const char *PyTypeObject.tp_doc

An optional pointer to a NUL-terminated C string giving the docstring for this type object. This is exposed as the __doc__ attribute on the type and instances of the type.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다.

traverseproc PyTypeObject.tp_traverse

An optional pointer to a traversal function for the garbage collector. This is only used if the Py_TPFLAGS_HAVE_GC flag bit is set. The signature is:

int tp_traverse(PyObject *self, visitproc visit, void *arg);

파이썬의 가비지 수집 체계에 대한 자세한 정보는 섹션 순환 가비지 수집 지원에서 찾을 수 있습니다.

The tp_traverse pointer is used by the garbage collector to detect reference cycles. A typical implementation of a tp_traverse function simply calls Py_VISIT() on each of the instance’s members that are Python objects that the instance owns. For example, this is function local_traverse() from the _thread extension module:

static int
local_traverse(localobject *self, visitproc visit, void *arg)
{
    Py_VISIT(self->args);
    Py_VISIT(self->kw);
    Py_VISIT(self->dict);
    return 0;
}

Py_VISIT()는 참조 순환에 참여할 수 있는 멤버에 대해서만 호출됨에 유의하십시오. self->key 멤버도 있지만, NULL이나 파이썬 문자열만 가능해서 참조 순환의 일부가 될 수 없습니다.

반면에, 멤버가 사이클의 일부가 될 수 없다는 것을 알고 있더라도, 디버깅 지원을 위해 gc 모듈의 get_referents() 함수가 그것을 포함하도록 어쨌거나 방문하고 싶을 수 있습니다.

Heap types (Py_TPFLAGS_HEAPTYPE) must visit their type with:

Py_VISIT(Py_TYPE(self));

It is only needed since Python 3.9. To support Python 3.8 and older, this line must be conditional:

#if PY_VERSION_HEX >= 0x03090000
    Py_VISIT(Py_TYPE(self));
#endif

If the Py_TPFLAGS_MANAGED_DICT bit is set in the tp_flags field, the traverse function must call PyObject_VisitManagedDict() like this:

PyObject_VisitManagedDict((PyObject*)self, visit, arg);

경고

When implementing tp_traverse, only the members that the instance owns (by having strong references to them) must be visited. For instance, if an object supports weak references via the tp_weaklist slot, the pointer supporting the linked list (what tp_weaklist points to) must not be visited as the instance does not directly own the weak references to itself (the weakreference list is there to support the weak reference machinery, but the instance has no strong reference to the elements inside it, as they are allowed to be removed even if the instance is still alive).

Note that Py_VISIT() requires the visit and arg parameters to local_traverse() to have these specific names; don’t name them just anything.

Instances of heap-allocated types hold a reference to their type. Their traversal function must therefore either visit Py_TYPE(self), or delegate this responsibility by calling tp_traverse of another heap-allocated type (such as a heap-allocated superclass). If they do not, the type object may not be garbage-collected.

버전 3.9에서 변경: 힙 할당 형은 tp_traverse에서 Py_TYPE(self)를 방문할 것으로 기대됩니다. 이전 버전의 파이썬에서는, 버그 40217 [https://bugs.python.org/issue40217]로 인해, 이렇게 하면 서브 클래스에서 충돌이 발생할 수 있습니다.

계승:

Group: Py_TPFLAGS_HAVE_GC, tp_traverse, tp_clear

This field is inherited by subtypes together with tp_clear and the Py_TPFLAGS_HAVE_GC flag bit: the flag bit, tp_traverse, and tp_clear are all inherited from the base type if they are all zero in the subtype.

inquiry PyTypeObject.tp_clear

An optional pointer to a clear function for the garbage collector. This is only used if the Py_TPFLAGS_HAVE_GC flag bit is set. The signature is:

int tp_clear(PyObject *);

tp_clear 멤버 함수는 가비지 수집기에서 감지한 순환 가비지에서 참조 순환을 끊는 데 사용됩니다. 종합하여, 시스템의 모든 tp_clear 함수가 결합하여 모든 참조 순환을 끊어야 합니다. 이것은 미묘합니다, 확신이 서지 않으면 tp_clear 함수를 제공하십시오. 예를 들어, 튜플 형은 tp_clear 함수를 구현하지 않습니다. 튜플만으로는 참조 순환이 구성될 수 없음을 증명할 수 있기 때문입니다. 따라서 다른 형의 tp_clear 함수만으로 튜플을 포함하는 순환을 끊기에 충분해야 합니다. 이것은 그리 자명하지 않으며, tp_clear를 구현하지 않아도 좋을 만한 이유는 거의 없습니다.

tp_clear의 구현은 다음 예제와 같이 파이썬 객체일 수 있는 자신의 멤버에 대한 인스턴스의 참조를 삭제하고 해당 멤버에 대한 포인터를 NULL로 설정해야 합니다:

static int
local_clear(localobject *self)
{
    Py_CLEAR(self->key);
    Py_CLEAR(self->args);
    Py_CLEAR(self->kw);
    Py_CLEAR(self->dict);
    return 0;
}

The Py_CLEAR() macro should be used, because clearing references is delicate: the reference to the contained object must not be released (via Py_DECREF()) until after the pointer to the contained object is set to NULL. This is because releasing the reference may cause the contained object to become trash, triggering a chain of reclamation activity that may include invoking arbitrary Python code (due to finalizers, or weakref callbacks, associated with the contained object). If it’s possible for such code to reference self again, it’s important that the pointer to the contained object be NULL at that time, so that self knows the contained object can no longer be used. The Py_CLEAR() macro performs the operations in a safe order.

If the Py_TPFLAGS_MANAGED_DICT bit is set in the tp_flags field, the traverse function must call PyObject_ClearManagedDict() like this:

PyObject_ClearManagedDict((PyObject*)self);

Note that tp_clear is not always called before an instance is deallocated. For example, when reference counting is enough to determine that an object is no longer used, the cyclic garbage collector is not involved and tp_dealloc is called directly.

tp_clear 함수의 목표는 참조 순환을 끊는 것이기 때문에, 참조 순환에 참여할 수 없는 파이썬 문자열이나 파이썬 정수와 같은 포함된 객체를 정리할 필요는 없습니다. 반면에, 포함된 모든 파이썬 객체를 정리하고, 형의 tp_dealloc 함수가 tp_clear를 호출하도록 작성하는 것이 편리할 수 있습니다.

파이썬의 가비지 수집 체계에 대한 자세한 정보는 섹션 순환 가비지 수집 지원에서 찾을 수 있습니다.

계승:

Group: Py_TPFLAGS_HAVE_GC, tp_traverse, tp_clear

This field is inherited by subtypes together with tp_traverse and the Py_TPFLAGS_HAVE_GC flag bit: the flag bit, tp_traverse, and tp_clear are all inherited from the base type if they are all zero in the subtype.

richcmpfunc PyTypeObject.tp_richcompare

풍부한 비교 함수(rich comparison function)에 대한 선택적 포인터. 서명은 다음과 같습니다:

PyObject *tp_richcompare(PyObject *self, PyObject *other, int op);

첫 번째 매개 변수는 PyTypeObject에 의해 정의된 형의 인스턴스임이 보장됩니다.

이 함수는 비교 결과(일반적으로 Py_True나 Py_False)를 반환해야 합니다. 비교가 정의되어 있지 않으면, Py_NotImplemented를 반환하고, 다른 에러가 발생하면 NULL을 반환하고 예외 조건을 설정해야 합니다.

다음 상수는 tp_richcompare와 PyObject_RichCompare()의 세 번째 인자로 사용되도록 정의됩니다:

상수

비교

Py_LT

<

Py_LE

<=

Py_EQ

==

Py_NE

!=

Py_GT

>

Py_GE

>=

풍부한 비교 함수를 쉽게 작성할 수 있도록 다음 매크로가 정의됩니다:

Py_RETURN_RICHCOMPARE(VAL_A, VAL_B, op)

비교 결과에 따라, 함수에서 Py_True나 Py_False를 반환합니다. VAL_A와 VAL_B는 C 비교 연산자로 순서를 정할 수 있어야 합니다 (예를 들어, C int나 float일 수 있습니다). 세 번째 인자는 PyObject_RichCompare()에서처럼 요청된 연산을 지정합니다.

The returned value is a new strong reference.

에러가 발생하면, 예외를 설정하고 함수에서 NULL을 반환합니다.

Added in version 3.7.

계승:

Group: tp_hash, tp_richcompare

이 필드는 tp_hash와 함께 서브 형에 의해 상속됩니다. 서브 형의 tp_richcompare와 tp_hash가 모두 NULL이면 서브 형은 tp_richcompare와 tp_hash를 상속합니다.

기본값:

PyBaseObject_Type provides a tp_richcompare implementation, which may be inherited. However, if only tp_hash is defined, not even the inherited function is used and instances of the type will not be able to participate in any comparisons.

Py_ssize_t PyTypeObject.tp_weaklistoffset

While this field is still supported, Py_TPFLAGS_MANAGED_WEAKREF should be used instead, if at all possible.

If the instances of this type are weakly referenceable, this field is greater than zero and contains the offset in the instance structure of the weak reference list head (ignoring the GC header, if present); this offset is used by PyObject_ClearWeakRefs() and the PyWeakref_* functions. The instance structure needs to include a field of type PyObject* which is initialized to NULL.

이 필드를 tp_weaklist와 혼동하지 마십시오; 그것은 형 객체 자체에 대한 약한 참조의 리스트 헤드입니다.

It is an error to set both the Py_TPFLAGS_MANAGED_WEAKREF bit and tp_weaklistoffset.

계승:

이 필드는 서브 형에 의해 상속되지만, 아래 나열된 규칙을 참조하십시오. 서브 형이 이 오프셋을 재정의할 수 있습니다; 이는 서브 형이 베이스형과 다른 약한 참조 리스트 헤드를 사용함을 의미합니다. 리스트 헤드는 항상 tp_weaklistoffset을 통해 발견되므로, 문제가 되지 않습니다.

기본값:

If the Py_TPFLAGS_MANAGED_WEAKREF bit is set in the tp_flags field, then tp_weaklistoffset will be set to a negative value, to indicate that it is unsafe to use this field.

getiterfunc PyTypeObject.tp_iter

An optional pointer to a function that returns an iterator for the object. Its presence normally signals that the instances of this type are iterable (although sequences may be iterable without this function).

이 함수는 PyObject_GetIter()와 같은 서명을 갖습니다:

PyObject *tp_iter(PyObject *self);

계승:

이 필드는 서브 형으로 상속됩니다.

iternextfunc PyTypeObject.tp_iternext

An optional pointer to a function that returns the next item in an iterator. The signature is:

PyObject *tp_iternext(PyObject *self);

이터레이터가 소진되면 NULL을 반환해야 합니다; StopIteration 예외가 설정될 수도, 그렇지 않을 수도 있습니다. 다른 에러가 발생하면, 역시 NULL을 반환해야 합니다. 그 존재는 이 형의 인스턴스가 이터레이터라는 신호입니다.

이터레이터 형은 tp_iter 함수도 정의해야 하며, 해당 함수는 (새 이터레이터 인스턴스가 아닌) 이터레이터 인스턴스 자체를 반환해야 합니다.

이 함수는 PyIter_Next()와 같은 서명을 갖습니다.

계승:

이 필드는 서브 형으로 상속됩니다.

struct PyMethodDef *PyTypeObject.tp_methods

이 형의 일반 메서드를 선언하는 PyMethodDef 구조체의 정적 NULL-종료 배열에 대한 선택적 포인터.

배열의 항목마다, 메서드 디스크립터를 포함하는 형의 딕셔너리(아래 tp_dict를 참조하십시오)에 항목이 추가됩니다.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다 (메서드는 다른 메커니즘을 통해 상속됩니다).

struct PyMemberDef *PyTypeObject.tp_members

이 형의 인스턴스의 일반 데이터 멤버(필드나 슬롯)를 선언하는 PyMemberDef 구조체의 정적 NULL-종료 배열에 대한 선택적 포인터.

배열의 항목마다, 멤버 디스크립터를 포함하는 형의 딕셔너리(아래 tp_dict를 참조하십시오)에 항목이 추가됩니다.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다 (멤버는 다른 메커니즘을 통해 상속됩니다).

struct PyGetSetDef *PyTypeObject.tp_getset

이 형의 인스턴스의 계산된 어트리뷰트를 선언하는 PyGetSetDef 구조체의 정적 NULL-종료 배열에 대한 선택적 포인터.

배열의 항목마다, getset 디스크립터를 포함하는 형의 딕셔너리(아래 tp_dict를 참조하십시오)에 항목이 추가됩니다.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다 (계산된 어트리뷰트는 다른 메커니즘을 통해 상속됩니다).

PyTypeObject *PyTypeObject.tp_base

형 속성이 상속되는 베이스형에 대한 선택적 포인터. 이 수준에서는, 단일 상속만 지원됩니다; 다중 상속은 메타 형을 호출하여 형 객체를 동적으로 작성해야 합니다.

참고

슬롯 초기화에는 전역 초기화 규칙이 적용됩니다. C99에서는 초기화자가 “주소 상수(address constants)”여야 합니다. 포인터로 묵시적으로 변환되는 PyType_GenericNew()와 같은 함수 지정자는 유효한 C99 주소 상수입니다.

However, the unary ‘&’ operator applied to a non-static variable like PyBaseObject_Type is not required to produce an address constant. Compilers may support this (gcc does), MSVC does not. Both compilers are strictly standard conforming in this particular behavior.

결과적으로, tp_base는 확장 모듈의 초기화 함수에서 설정되어야 합니다.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다 (명백히).

기본값:

이 필드의 기본값은 &PyBaseObject_Type입니다 (파이썬 프로그래머에게는 object 형으로 알려져 있습니다).

PyObject *PyTypeObject.tp_dict

형의 딕셔너리는 PyType_Ready()에 의해 여기에 저장됩니다.

This field should normally be initialized to NULL before PyType_Ready is called; it may also be initialized to a dictionary containing initial attributes for the type. Once PyType_Ready() has initialized the type, extra attributes for the type may be added to this dictionary only if they don’t correspond to overloaded operations (like __add__()). Once initialization for the type has finished, this field should be treated as read-only.

Some types may not store their dictionary in this slot. Use PyType_GetDict() to retrieve the dictionary for an arbitrary type.

버전 3.12에서 변경: Internals detail: For static builtin types, this is always NULL. Instead, the dict for such types is stored on PyInterpreterState. Use PyType_GetDict() to get the dict for an arbitrary type.

계승:

이 필드는 서브 형에 의해 상속되지 않습니다 (여기에 정의된 어트리뷰트는 다른 메커니즘을 통해 상속됩니다).

기본값:

이 필드가 NULL이면, PyType_Ready()는 새 딕셔너리를 할당합니다.

경고

PyDict_SetItem()을 사용하거나 다른 식으로 딕셔너리 C-API로 tp_dict를 수정하는 것은 안전하지 않습니다.

descrgetfunc PyTypeObject.tp_descr_get

“디스크립터 get” 함수에 대한 선택적 포인터.

함수 서명은 다음과 같습니다:

PyObject * tp_descr_get(PyObject *self, PyObject *obj, PyObject *type);

계승:

이 필드는 서브 형으로 상속됩니다.

descrsetfunc PyTypeObject.tp_descr_set

디스크립터 값을 설정하고 삭제하기 위한 함수에 대한 선택적 포인터.

함수 서명은 다음과 같습니다:

int tp_descr_set(PyObject *self, PyObject *obj, PyObject *value);

value 인자는 값을 삭제하기 위해 NULL로 설정됩니다.

계승:

이 필드는 서브 형으로 상속됩니다.

Py_ssize_t PyTypeObject.tp_dictoffset

While this field is still supported, Py_TPFLAGS_MANAGED_DICT should be used instead, if at all possible.

이 형의 인스턴스에 인스턴스 변수를 포함하는 딕셔너리가 있으면, 이 필드는 0이 아니며 인스턴스 변수 딕셔너리 형의 인스턴스에서의 오프셋을 포함합니다; 이 오프셋은 PyObject_GenericGetAttr()에서 사용됩니다.

이 필드를 tp_dict와 혼동하지 마십시오; 그것은 형 객체 자체의 어트리뷰트에 대한 딕셔너리입니다.

The value specifies the offset of the dictionary from the start of the instance structure.

The tp_dictoffset should be regarded as write-only. To get the pointer to the dictionary call PyObject_GenericGetDict(). Calling PyObject_GenericGetDict() may need to allocate memory for the dictionary, so it is may be more efficient to call PyObject_GetAttr() when accessing an attribute on the object.

It is an error to set both the Py_TPFLAGS_MANAGED_WEAKREF bit and tp_dictoffset.

계승:

This field is inherited by subtypes. A subtype should not override this offset; doing so could be unsafe, if C code tries to access the dictionary at the previous offset. To properly support inheritance, use Py_TPFLAGS_MANAGED_DICT.

기본값:

This slot has no default. For static types, if the field is NULL then no __dict__ gets created for instances.

If the Py_TPFLAGS_MANAGED_DICT bit is set in the tp_flags field, then tp_dictoffset will be set to -1, to indicate that it is unsafe to use this field.

initproc PyTypeObject.tp_init

인스턴스 초기화 함수에 대한 선택적 포인터.

This function corresponds to the __init__() method of classes. Like __init__(), it is possible to create an instance without calling __init__(), and it is possible to reinitialize an instance by calling its __init__() method again.

함수 서명은 다음과 같습니다:

int tp_init(PyObject *self, PyObject *args, PyObject *kwds);

The self argument is the instance to be initialized; the args and kwds arguments represent positional and keyword arguments of the call to __init__().

NULL이 아닐 때, tp_init 함수는 형을 호출하여 인스턴스를 정상적으로 만들 때, 형의 tp_new 함수가 형의 인스턴스를 반환한 후 호출됩니다. tp_new 함수가 원래 형의 서브 형이 아닌 다른 형의 인스턴스를 반환하면, 아무런 tp_init 함수도 호출되지 않습니다; tp_new가 원래 형의 서브 형 인스턴스를 반환하면, 서브 형의 tp_init가 호출됩니다.

성공하면 0을 반환하고, 에러 시에는 -1을 반환하고 예외를 설정합니다.

계승:

이 필드는 서브 형으로 상속됩니다.

기본값:

For static types this field does not have a default.

allocfunc PyTypeObject.tp_alloc

인스턴스 할당 함수에 대한 선택적 포인터.

함수 서명은 다음과 같습니다:

PyObject *tp_alloc(PyTypeObject *self, Py_ssize_t nitems);

계승:

이 필드는 정적 서브 형에 의해 상속되지만, 동적 서브 형(클래스 문으로 만들어진 서브 형)에는 상속되지 않습니다.

기본값:

동적 서브 형의 경우, 이 필드는 표준 힙 할당 전략을 강제하기 위해 항상 PyType_GenericAlloc()으로 설정됩니다.

For static subtypes, PyBaseObject_Type uses PyType_GenericAlloc(). That is the recommended value for all statically defined types.

newfunc PyTypeObject.tp_new

인스턴스 생성 함수에 대한 선택적 포인터.

함수 서명은 다음과 같습니다:

PyObject *tp_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds);

subtype 인자는 만들어지고 있는 객체의 형입니다; args와 kwds 인자는 형 호출의 위치와 키워드 인자를 나타냅니다. subtype이 tp_new 함수가 호출되는 형과 같을 필요는 없음에 유의하십시오; 이 형의 서브 형일 수 있습니다 (하지만 관련이 없는 형은 아닙니다).

tp_new 함수는 객체에 공간을 할당하기 위해 subtype->tp_alloc(subtype, nitems)를 호출해야 하고, 그런 다음 꼭 필요한 만큼만 추가 초기화를 수행해야 합니다. 안전하게 무시하거나 반복할 수 있는 초기화는 tp_init 처리기에 배치해야 합니다. 간단한 규칙은, 불변 형의 경우 모든 초기화가 tp_new에서 수행되어야 하고, 가변형의 경우 대부분 초기화는 tp_init로 미뤄져야 합니다.

Set the Py_TPFLAGS_DISALLOW_INSTANTIATION flag to disallow creating instances of the type in Python.

계승:

This field is inherited by subtypes, except it is not inherited by static types whose tp_base is NULL or &PyBaseObject_Type.

기본값:

For static types this field has no default. This means if the slot is defined as NULL, the type cannot be called to create new instances; presumably there is some other way to create instances, like a factory function.

freefunc PyTypeObject.tp_free

인스턴스 할당 해제 함수에 대한 선택적 포인터. 서명은 다음과 같습니다:

void tp_free(void *self);

이 서명과 호환되는 초기화자는 PyObject_Free()입니다.

계승:

이 필드는 정적 서브 형에 의해 상속되지만, 동적 서브 형(클래스 문으로 만들어진 서브 형)에는 상속되지 않습니다.

기본값:

In dynamic subtypes, this field is set to a deallocator suitable to match PyType_GenericAlloc() and the value of the Py_TPFLAGS_HAVE_GC flag bit.

For static subtypes, PyBaseObject_Type uses PyObject_Free().

inquiry PyTypeObject.tp_is_gc

가비지 수집기에서 호출되는 함수에 대한 선택적 포인터.

The garbage collector needs to know whether a particular object is collectible or not. Normally, it is sufficient to look at the object’s type’s tp_flags field, and check the Py_TPFLAGS_HAVE_GC flag bit. But some types have a mixture of statically and dynamically allocated instances, and the statically allocated instances are not collectible. Such types should define this function; it should return 1 for a collectible instance, and 0 for a non-collectible instance. The signature is:

int tp_is_gc(PyObject *self);

(The only example of this are types themselves. The metatype, PyType_Type, defines this function to distinguish between statically and dynamically allocated types.)

계승:

이 필드는 서브 형으로 상속됩니다.

기본값:

This slot has no default. If this field is NULL, Py_TPFLAGS_HAVE_GC is used as the functional equivalent.

PyObject *PyTypeObject.tp_bases

베이스형의 튜플.

This field should be set to NULL and treated as read-only. Python will fill it in when the type is initialized.

For dynamically created classes, the Py_tp_bases slot can be used instead of the bases argument of PyType_FromSpecWithBases(). The argument form is preferred.

경고

Multiple inheritance does not work well for statically defined types. If you set tp_bases to a tuple, Python will not raise an error, but some slots will only be inherited from the first base.

계승:

이 필드는 상속되지 않습니다.

PyObject *PyTypeObject.tp_mro

형 자체에서 시작하여 object로 끝나는 확장된 베이스형 집합을 포함하는 튜플.

This field should be set to NULL and treated as read-only. Python will fill it in when the type is initialized.

계승:

이 필드는 상속되지 않습니다; PyType_Ready()에 의해 새로 계산됩니다.

PyObject *PyTypeObject.tp_cache

사용되지 않습니다. 내부 전용.

계승:

이 필드는 상속되지 않습니다.

void *PyTypeObject.tp_subclasses

A collection of subclasses. Internal use only. May be an invalid pointer.

To get a list of subclasses, call the Python method __subclasses__().

버전 3.12에서 변경: For some types, this field does not hold a valid PyObject*. The type was changed to void* to indicate this.

계승:

이 필드는 상속되지 않습니다.

PyObject *PyTypeObject.tp_weaklist

이 형 객체에 대한 약한 참조를 위한 약한 참조 리스트 헤드. 상속되지 않습니다. 내부 전용.

버전 3.12에서 변경: Internals detail: For the static builtin types this is always NULL, even if weakrefs are added. Instead, the weakrefs for each are stored on PyInterpreterState. Use the public C-API or the internal _PyObject_GET_WEAKREFS_LISTPTR() macro to avoid the distinction.

계승:

이 필드는 상속되지 않습니다.

destructor PyTypeObject.tp_del

이 필드는 폐지되었습니다. 대신 tp_finalize를 사용하십시오.

unsigned int PyTypeObject.tp_version_tag

메서드 캐시에 인덱싱하는 데 사용됩니다. 내부 전용.

계승:

이 필드는 상속되지 않습니다.

destructor PyTypeObject.tp_finalize

인스턴스 파이널리제이션 함수에 대한 선택적 포인터. 서명은 다음과 같습니다:

void tp_finalize(PyObject *self);

tp_finalize가 설정되면, 인터프리터는 인스턴스를 파이널라이즈 할 때 이를 한 번 호출합니다. 가비지 수집기(인스턴스가 격리된 참조 순환의 일부인 경우)나 객체가 할당 해제되기 직전에 호출됩니다. 어느 쪽이든, 참조 순환을 끊기 전에 호출되어 정상 상태에 있는 객체를 보도록 보장합니다.

tp_finalize는 현재 예외 상태를 변경하지 않아야 합니다; 따라서 사소하지 않은 파이널라이저를 작성하는 권장 방법은 다음과 같습니다:

static void
local_finalize(PyObject *self)
{
    PyObject *error_type, *error_value, *error_traceback;

    /* Save the current exception, if any. */
    PyErr_Fetch(&error_type, &error_value, &error_traceback);

    /* ... */

    /* Restore the saved exception. */
    PyErr_Restore(error_type, error_value, error_traceback);
}

계승:

이 필드는 서브 형으로 상속됩니다.

Added in version 3.4.

버전 3.8에서 변경: Before version 3.8 it was necessary to set the Py_TPFLAGS_HAVE_FINALIZE flags bit in order for this field to be used. This is no longer required.

더 보기

“안전한 객체 파이널리제이션” (PEP 442 [https://peps.python.org/pep-0442/])

vectorcallfunc PyTypeObject.tp_vectorcall

A vectorcall function to use for calls of this type object (rather than instances). In other words, tp_vectorcall can be used to optimize type.__call__, which typically returns a new instance of type.

As with any vectorcall function, if tp_vectorcall is NULL, the tp_call protocol (Py_TYPE(type)->tp_call) is used instead.

참고

The vectorcall protocol requires that the vectorcall function has the same behavior as the corresponding tp_call. This means that type->tp_vectorcall must match the behavior of Py_TYPE(type)->tp_call.

Specifically, if type uses the default metaclass, type->tp_vectorcall must behave the same as PyType_Type->tp_call, which:

calls type->tp_new,

if the result is a subclass of type, calls type->tp_init on the result of tp_new, and

returns the result of tp_new.

Typically, tp_vectorcall is overridden to optimize this process for specific tp_new and tp_init. When doing this for user-subclassable types, note that both can be overridden (using __new__() and __init__(), respectively).

계승:

이 필드는 상속되지 않습니다.

Added in version 3.9: (필드는 3.8부터 존재하지만 3.9부터 사용됩니다)

unsigned char PyTypeObject.tp_watched

Internal. Do not use.

Added in version 3.12.

Static Types

전통적으로, C 코드에서 정의된 형은 정적(static)입니다. 즉 정적 PyTypeObject 구조체는 코드에서 직접 정의되고 PyType_Ready()를 사용하여 초기화됩니다.

결과적으로 파이썬에서 정의된 형에 비해 형이 제한됩니다:

정적 형은 하나의 베이스로 제한됩니다. 즉, 다중 상속을 사용할 수 없습니다.

정적 형 객체(그러나 이들의 인스턴스는 아닙니다)는 불변입니다. 파이썬에서 형 객체의 어트리뷰트를 추가하거나 수정할 수 없습니다.

정적 형 객체는 서브 인터프리터에서 공유되므로, 서브 인터프리터 관련 상태를 포함하지 않아야 합니다.

Also, since PyTypeObject is only part of the Limited API as an opaque struct, any extension modules using static types must be compiled for a specific Python minor version.

힙 형

An alternative to static types is heap-allocated types, or heap types for short, which correspond closely to classes created by Python’s class statement. Heap types have the Py_TPFLAGS_HEAPTYPE flag set.

This is done by filling a PyType_Spec structure and calling PyType_FromSpec(), PyType_FromSpecWithBases(), PyType_FromModuleAndSpec(), or PyType_FromMetaclass().

숫자 객체 구조체

type PyNumberMethods

이 구조체는 객체가 숫자 프로토콜을 구현하는 데 사용하는 함수에 대한 포인터를 담습니다. 각 함수는 숫자 프로토콜 섹션에서 설명하는 유사한 이름의 함수가 사용합니다.

구조체 정의는 다음과 같습니다:

typedef struct {
     binaryfunc nb_add;
     binaryfunc nb_subtract;
     binaryfunc nb_multiply;
     binaryfunc nb_remainder;
     binaryfunc nb_divmod;
     ternaryfunc nb_power;
     unaryfunc nb_negative;
     unaryfunc nb_positive;
     unaryfunc nb_absolute;
     inquiry nb_bool;
     unaryfunc nb_invert;
     binaryfunc nb_lshift;
     binaryfunc nb_rshift;
     binaryfunc nb_and;
     binaryfunc nb_xor;
     binaryfunc nb_or;
     unaryfunc nb_int;
     void *nb_reserved;
     unaryfunc nb_float;

     binaryfunc nb_inplace_add;
     binaryfunc nb_inplace_subtract;
     binaryfunc nb_inplace_multiply;
     binaryfunc nb_inplace_remainder;
     ternaryfunc nb_inplace_power;
     binaryfunc nb_inplace_lshift;
     binaryfunc nb_inplace_rshift;
     binaryfunc nb_inplace_and;
     binaryfunc nb_inplace_xor;
     binaryfunc nb_inplace_or;

     binaryfunc nb_floor_divide;
     binaryfunc nb_true_divide;
     binaryfunc nb_inplace_floor_divide;
     binaryfunc nb_inplace_true_divide;

     unaryfunc nb_index;

     binaryfunc nb_matrix_multiply;
     binaryfunc nb_inplace_matrix_multiply;
} PyNumberMethods;

참고

이항과 삼항 함수는 모든 피연산자의 형을 확인하고, 필요한 변환을 구현해야합니다 (적어도 피연산자 중 하나는 정의된 형의 인스턴스입니다). 주어진 피연산자에 대해 연산이 정의되지 않으면, 이항과 삼항 함수는 Py_NotImplemented를 반환해야하며, 다른 에러가 발생하면 NULL을 반환하고 예외를 설정해야 합니다.

참고

The nb_reserved field should always be NULL. It was previously called nb_long, and was renamed in Python 3.0.1.

binaryfunc PyNumberMethods.nb_add

binaryfunc PyNumberMethods.nb_subtract

binaryfunc PyNumberMethods.nb_multiply

binaryfunc PyNumberMethods.nb_remainder

binaryfunc PyNumberMethods.nb_divmod

ternaryfunc PyNumberMethods.nb_power

unaryfunc PyNumberMethods.nb_negative

unaryfunc PyNumberMethods.nb_positive

unaryfunc PyNumberMethods.nb_absolute

inquiry PyNumberMethods.nb_bool

unaryfunc PyNumberMethods.nb_invert

binaryfunc PyNumberMethods.nb_lshift

binaryfunc PyNumberMethods.nb_rshift

binaryfunc PyNumberMethods.nb_and

binaryfunc PyNumberMethods.nb_xor

binaryfunc PyNumberMethods.nb_or

unaryfunc PyNumberMethods.nb_int

void *PyNumberMethods.nb_reserved

unaryfunc PyNumberMethods.nb_float

binaryfunc PyNumberMethods.nb_inplace_add

binaryfunc PyNumberMethods.nb_inplace_subtract

binaryfunc PyNumberMethods.nb_inplace_multiply

binaryfunc PyNumberMethods.nb_inplace_remainder

ternaryfunc PyNumberMethods.nb_inplace_power

binaryfunc PyNumberMethods.nb_inplace_lshift

binaryfunc PyNumberMethods.nb_inplace_rshift

binaryfunc PyNumberMethods.nb_inplace_and

binaryfunc PyNumberMethods.nb_inplace_xor

binaryfunc PyNumberMethods.nb_inplace_or

binaryfunc PyNumberMethods.nb_floor_divide

binaryfunc PyNumberMethods.nb_true_divide

binaryfunc PyNumberMethods.nb_inplace_floor_divide

binaryfunc PyNumberMethods.nb_inplace_true_divide

unaryfunc PyNumberMethods.nb_index

binaryfunc PyNumberMethods.nb_matrix_multiply

binaryfunc PyNumberMethods.nb_inplace_matrix_multiply

매핑 객체 구조체

type PyMappingMethods

이 구조체에는 객체가 매핑 프로토콜을 구현하는 데 사용하는 함수에 대한 포인터를 담습니다. 세 개의 멤버가 있습니다:

lenfunc PyMappingMethods.mp_length

이 함수는 PyMapping_Size()와 PyObject_Size()에서 사용되며, 같은 서명을 갖습니다. 객체에 길이가 정의되어 있지 않으면 이 슬롯을 NULL로 설정할 수 있습니다.

binaryfunc PyMappingMethods.mp_subscript

이 함수는 PyObject_GetItem()과 PySequence_GetSlice()에서 사용되며, PyObject_GetItem()과 같은 서명을 갖습니다. PyMapping_Check() 함수가 1을 반환하려면, 이 슬롯을 채워야합니다, 그렇지 않으면 NULL일 수 있습니다.

objobjargproc PyMappingMethods.mp_ass_subscript

This function is used by PyObject_SetItem(), PyObject_DelItem(), PySequence_SetSlice() and PySequence_DelSlice(). It has the same signature as PyObject_SetItem(), but v can also be set to NULL to delete an item. If this slot is NULL, the object does not support item assignment and deletion.

시퀀스 객체 구조체

type PySequenceMethods

이 구조체는 객체가 시퀀스 프로토콜을 구현하는 데 사용하는 함수에 대한 포인터를 담습니다.

lenfunc PySequenceMethods.sq_length

이 함수는 PySequence_Size()와 PyObject_Size()에서 사용되며, 같은 서명을 갖습니다. 또한 sq_item과 sq_ass_item 슬롯을 통해 음수 인덱스를 처리하는 데 사용됩니다.

binaryfunc PySequenceMethods.sq_concat

이 함수는 PySequence_Concat()에서 사용되며 같은 서명을 갖습니다. nb_add 슬롯을 통해 숫자 덧셈을 시도한 후, + 연산자에서도 사용됩니다.

ssizeargfunc PySequenceMethods.sq_repeat

이 함수는 PySequence_Repeat()에서 사용되며 같은 서명을 갖습니다. nb_multiply 슬롯을 통해 숫자 곱셈을 시도한 후, * 연산자에서도 사용됩니다.

ssizeargfunc PySequenceMethods.sq_item

이 함수는 PySequence_GetItem()에서 사용되며 같은 서명을 갖습니다. mp_subscript 슬롯을 통해 서브스크립션(subscription)을 시도한 후, PyObject_GetItem()에서도 사용됩니다. PySequence_Check() 함수가 1을 반환하려면, 이 슬롯을 채워야합니다, 그렇지 않으면 NULL일 수 있습니다.

Negative indexes are handled as follows: if the sq_length slot is filled, it is called and the sequence length is used to compute a positive index which is passed to sq_item. If sq_length is NULL, the index is passed as is to the function.

ssizeobjargproc PySequenceMethods.sq_ass_item

이 함수는 PySequence_SetItem()에서 사용되며 같은 서명을 갖습니다. mp_ass_subscript 슬롯을 통해 항목 대입과 삭제를 시도한 후, PyObject_SetItem()과 PyObject_DelItem()에서도 사용됩니다. 객체가 항목 대입과 삭제를 지원하지 않으면 이 슬롯은 NULL로 남겨 둘 수 있습니다.

objobjproc PySequenceMethods.sq_contains

이 함수는 PySequence_Contains()에서 사용될 수 있으며 같은 서명을 갖습니다. 이 슬롯은 NULL로 남겨 둘 수 있습니다, 이때 PySequence_Contains()는 일치하는 것을 찾을 때까지 시퀀스를 단순히 탐색합니다.

binaryfunc PySequenceMethods.sq_inplace_concat

이 함수는 PySequence_InPlaceConcat()에서 사용되며 같은 서명을 갖습니다. 첫 번째 피연산자를 수정하고 그것을 반환해야 합니다. 이 슬롯은 NULL로 남겨 둘 수 있으며, 이때 PySequence_InPlaceConcat()은 PySequence_Concat()으로 폴백 됩니다. nb_inplace_add 슬롯을 통해 숫자 제자리 덧셈을 시도한 후, 증분 대입 +=에서 사용됩니다.

ssizeargfunc PySequenceMethods.sq_inplace_repeat

이 함수는 PySequence_InPlaceRepeat()에서 사용되며 같은 서명을 갖습니다. 첫 번째 피연산자를 수정하고 그것을 반환해야 합니다. 이 슬롯은 NULL로 남겨 둘 수 있으며, 이때 PySequence_InPlaceRepeat()는 PySequence_Repeat()로 폴백 됩니다. nb_inplace_multiply 슬롯을 통해 숫자 제자리 곱셈을 시도한 후, 증분 대입 *=에서도 사용됩니다.

버퍼 객체 구조체

type PyBufferProcs

이 구조체는 버퍼 프로토콜에 필요한 함수에 대한 포인터를 담습니다. 프로토콜은 제공자(exporter) 객체가 내부 데이터를 소비자 객체에 노출하는 방법을 정의합니다.

getbufferproc PyBufferProcs.bf_getbuffer

이 함수의 서명은 다음과 같습니다:

int (PyObject *exporter, Py_buffer *view, int flags);

view를 채우기 위해 exporter에 대한 flags에 지정된 요청을 처리합니다. 포인트 (3) 을 제외하고, 이 함수의 구현은 다음 단계를 반드시 수행해야 합니다:

Check if the request can be met. If not, raise BufferError, set view->obj to NULL and return -1.

요청된 필드를 채웁니다.

내보내기 횟수에 대한 내부 카운터를 증가시킵니다.

Set view->obj to exporter and increment view->obj.

0을 반환합니다.

exporter가 버퍼 공급자의 체인이나 트리의 일부이면, 두 가지 주요 체계를 사용할 수 있습니다:

Re-export: Each member of the tree acts as the exporting object and sets view->obj to a new reference to itself.

Redirect: The buffer request is redirected to the root object of the tree. Here, view->obj will be a new reference to the root object.

view의 개별 필드는 섹션 버퍼 구조체에 설명되어 있으며, 제공자가 특정 요청에 응답해야 하는 규칙은 섹션 버퍼 요청 유형에 있습니다.

Py_buffer 구조체에서 가리키는 모든 메모리는 제공자에게 속하며 남은 소비자가 없어질 때까지 유효해야 합니다. format, shape, strides, suboffsets 및 internal은 소비자에게는 읽기 전용입니다.

PyBuffer_FillInfo()는 모든 요청 유형을 올바르게 처리하면서 간단한 바이트열 버퍼를 쉽게 노출 할 수 있는 방법을 제공합니다.

PyObject_GetBuffer()는 이 함수를 감싸는 소비자 용 인터페이스입니다.

releasebufferproc PyBufferProcs.bf_releasebuffer

이 함수의 서명은 다음과 같습니다:

void (PyObject *exporter, Py_buffer *view);

버퍼 자원 해제 요청을 처리합니다. 자원을 해제할 필요가 없으면, PyBufferProcs.bf_releasebuffer는 NULL일 수 있습니다. 그렇지 않으면, 이 함수의 표준 구현은 다음과 같은 선택적 단계를 수행합니다:

내보내기 횟수에 대한 내부 카운터를 줄입니다.

카운터가 0이면, view와 관련된 모든 메모리를 해제합니다.

제공자는 반드시 internal 필드를 사용하여 버퍼 특정 자원을 추적해야 합니다. 이 필드는 변경되지 않고 유지됨이 보장되지만, 소비자는 원래 버퍼의 사본을 view 인자로 전달할 수 있습니다.

This function MUST NOT decrement view->obj, since that is done automatically in PyBuffer_Release() (this scheme is useful for breaking reference cycles).

PyBuffer_Release()는 이 기능을 감싸는 소비자 용 인터페이스입니다.

비동기 객체 구조체

Added in version 3.5.

type PyAsyncMethods

이 구조체는 어웨이터블와 비동기 이터레이터 객체를 구현하는 데 필요한 함수에 대한 포인터를 담습니다.

구조체 정의는 다음과 같습니다:

typedef struct {
    unaryfunc am_await;
    unaryfunc am_aiter;
    unaryfunc am_anext;
    sendfunc am_send;
} PyAsyncMethods;

unaryfunc PyAsyncMethods.am_await

이 함수의 서명은 다음과 같습니다:

PyObject *am_await(PyObject *self);

The returned object must be an iterator, i.e. PyIter_Check() must return 1 for it.

객체가 어웨이터블이 아니면 이 슬롯을 NULL로 설정할 수 있습니다.

unaryfunc PyAsyncMethods.am_aiter

이 함수의 서명은 다음과 같습니다:

PyObject *am_aiter(PyObject *self);

Must return an asynchronous iterator object. See __anext__() for details.

객체가 비동기 이터레이션 프로토콜을 구현하지 않으면 이 슬롯은 NULL로 설정될 수 있습니다.

unaryfunc PyAsyncMethods.am_anext

이 함수의 서명은 다음과 같습니다:

PyObject *am_anext(PyObject *self);

Must return an awaitable object. See __anext__() for details. This slot may be set to NULL.

sendfunc PyAsyncMethods.am_send

이 함수의 서명은 다음과 같습니다:

PySendResult am_send(PyObject *self, PyObject *arg, PyObject **result);

See PyIter_Send() for details. This slot may be set to NULL.

Added in version 3.10.

슬롯 형 typedef

typedef PyObject *(*allocfunc)(PyTypeObject *cls, Py_ssize_t nitems)

Part of the Stable ABI.

The purpose of this function is to separate memory allocation from memory initialization. It should return a pointer to a block of memory of adequate length for the instance, suitably aligned, and initialized to zeros, but with ob_refcnt set to 1 and ob_type set to the type argument. If the type’s tp_itemsize is non-zero, the object’s ob_size field should be initialized to nitems and the length of the allocated memory block should be tp_basicsize + nitems*tp_itemsize, rounded up to a multiple of sizeof(void*); otherwise, nitems is not used and the length of the block should be tp_basicsize.

이 함수는 다른 인스턴스 초기화를 수행하지 않아야 합니다, 추가 메모리를 할당도 안 됩니다; 그것은 tp_new에 의해 수행되어야 합니다.

typedef void (*destructor)(PyObject*)

Part of the Stable ABI.

typedef void (*freefunc)(void*)

tp_free를 참조하십시오.

typedef PyObject *(*newfunc)(PyTypeObject*, PyObject*, PyObject*)

Part of the Stable ABI.

tp_new를 참조하십시오.

typedef int (*initproc)(PyObject*, PyObject*, PyObject*)

Part of the Stable ABI.

tp_init를 참조하십시오.

typedef PyObject *(*reprfunc)(PyObject*)

Part of the Stable ABI.

tp_repr을 참조하십시오.

typedef PyObject *(*getattrfunc)(PyObject *self, char *attr)

Part of the Stable ABI.

객체의 명명된 어트리뷰트 값을 반환합니다.

typedef int (*setattrfunc)(PyObject *self, char *attr, PyObject *value)

Part of the Stable ABI.

객체의 명명된 어트리뷰트 값을 설정합니다. 어트리뷰트를 삭제하려면 value 인자가 NULL로 설정됩니다.

typedef PyObject *(*getattrofunc)(PyObject *self, PyObject *attr)

Part of the Stable ABI.

객체의 명명된 어트리뷰트 값을 반환합니다.

tp_getattro를 참조하십시오.

typedef int (*setattrofunc)(PyObject *self, PyObject *attr, PyObject *value)

Part of the Stable ABI.

객체의 명명된 어트리뷰트 값을 설정합니다. 어트리뷰트를 삭제하려면 value 인자가 NULL로 설정됩니다.

tp_setattro를 참조하십시오.

typedef PyObject *(*descrgetfunc)(PyObject*, PyObject*, PyObject*)

Part of the Stable ABI.

See tp_descr_get.

typedef int (*descrsetfunc)(PyObject*, PyObject*, PyObject*)

Part of the Stable ABI.

See tp_descr_set.

typedef Py_hash_t (*hashfunc)(PyObject*)

Part of the Stable ABI.

tp_hash를 참조하십시오.

typedef PyObject *(*richcmpfunc)(PyObject*, PyObject*, int)

Part of the Stable ABI.

tp_richcompare를 참조하십시오.

typedef PyObject *(*getiterfunc)(PyObject*)

Part of the Stable ABI.

tp_iter를 참조하십시오.

typedef PyObject *(*iternextfunc)(PyObject*)

Part of the Stable ABI.

tp_iternext를 참조하십시오.

typedef Py_ssize_t (*lenfunc)(PyObject*)

Part of the Stable ABI.

typedef int (*getbufferproc)(PyObject*, Py_buffer*, int)

Part of the Stable ABI since version 3.12.

typedef void (*releasebufferproc)(PyObject*, Py_buffer*)

Part of the Stable ABI since version 3.12.

typedef PyObject *(*unaryfunc)(PyObject*)

Part of the Stable ABI.

typedef PyObject *(*binaryfunc)(PyObject*, PyObject*)

Part of the Stable ABI.

typedef PySendResult (*sendfunc)(PyObject*, PyObject*, PyObject**)

See am_send.

typedef PyObject *(*ternaryfunc)(PyObject*, PyObject*, PyObject*)

Part of the Stable ABI.

typedef PyObject *(*ssizeargfunc)(PyObject*, Py_ssize_t)

Part of the Stable ABI.

typedef int (*ssizeobjargproc)(PyObject*, Py_ssize_t, PyObject*)

Part of the Stable ABI.

typedef int (*objobjproc)(PyObject*, PyObject*)

Part of the Stable ABI.

typedef int (*objobjargproc)(PyObject*, PyObject*, PyObject*)

Part of the Stable ABI.

예

다음은 파이썬 형 정의의 간단한 예입니다. 여기에는 여러분이 만날 수 있는 일반적인 사용법이 포함됩니다. 일부는 까다로운 코너 사례를 보여줍니다. 더 많은 예제, 실용 정보 및 자습서는 확장형 정의하기: 자습서와 확장형 정의하기: 여러 가지 주제를 참조하십시오.

A basic static type:

typedef struct {
    PyObject_HEAD
    const char *data;
} MyObject;

static PyTypeObject MyObject_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "mymod.MyObject",
    .tp_basicsize = sizeof(MyObject),
    .tp_doc = PyDoc_STR("My objects"),
    .tp_new = myobj_new,
    .tp_dealloc = (destructor)myobj_dealloc,
    .tp_repr = (reprfunc)myobj_repr,
};

더 상세한 초기화자를 사용하는 이전 코드(특히 CPython 코드 베이스에서)를 찾을 수도 있습니다:

static PyTypeObject MyObject_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "mymod.MyObject",               /* tp_name */
    sizeof(MyObject),               /* tp_basicsize */
    0,                              /* tp_itemsize */
    (destructor)myobj_dealloc,      /* tp_dealloc */
    0,                              /* tp_vectorcall_offset */
    0,                              /* tp_getattr */
    0,                              /* tp_setattr */
    0,                              /* tp_as_async */
    (reprfunc)myobj_repr,           /* tp_repr */
    0,                              /* tp_as_number */
    0,                              /* tp_as_sequence */
    0,                              /* tp_as_mapping */
    0,                              /* tp_hash */
    0,                              /* tp_call */
    0,                              /* tp_str */
    0,                              /* tp_getattro */
    0,                              /* tp_setattro */
    0,                              /* tp_as_buffer */
    0,                              /* tp_flags */
    PyDoc_STR("My objects"),        /* tp_doc */
    0,                              /* tp_traverse */
    0,                              /* tp_clear */
    0,                              /* tp_richcompare */
    0,                              /* tp_weaklistoffset */
    0,                              /* tp_iter */
    0,                              /* tp_iternext */
    0,                              /* tp_methods */
    0,                              /* tp_members */
    0,                              /* tp_getset */
    0,                              /* tp_base */
    0,                              /* tp_dict */
    0,                              /* tp_descr_get */
    0,                              /* tp_descr_set */
    0,                              /* tp_dictoffset */
    0,                              /* tp_init */
    0,                              /* tp_alloc */
    myobj_new,                      /* tp_new */
};

약한 참조, 인스턴스 딕셔너리 및 해싱을 지원하는 형:

typedef struct {
    PyObject_HEAD
    const char *data;
} MyObject;

static PyTypeObject MyObject_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "mymod.MyObject",
    .tp_basicsize = sizeof(MyObject),
    .tp_doc = PyDoc_STR("My objects"),
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
         Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_MANAGED_DICT |
         Py_TPFLAGS_MANAGED_WEAKREF,
    .tp_new = myobj_new,
    .tp_traverse = (traverseproc)myobj_traverse,
    .tp_clear = (inquiry)myobj_clear,
    .tp_alloc = PyType_GenericNew,
    .tp_dealloc = (destructor)myobj_dealloc,
    .tp_repr = (reprfunc)myobj_repr,
    .tp_hash = (hashfunc)myobj_hash,
    .tp_richcompare = PyBaseObject_Type.tp_richcompare,
};

A str subclass that cannot be subclassed and cannot be called to create instances (e.g. uses a separate factory func) using Py_TPFLAGS_DISALLOW_INSTANTIATION flag:

typedef struct {
    PyUnicodeObject raw;
    char *extra;
} MyStr;

static PyTypeObject MyStr_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "mymod.MyStr",
    .tp_basicsize = sizeof(MyStr),
    .tp_base = NULL,  // set to &PyUnicode_Type in module init
    .tp_doc = PyDoc_STR("my custom str"),
    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,
    .tp_repr = (reprfunc)myobj_repr,
};

The simplest static type with fixed-length instances:

typedef struct {
    PyObject_HEAD
} MyObject;

static PyTypeObject MyObject_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "mymod.MyObject",
};

The simplest static type with variable-length instances:

typedef struct {
    PyObject_VAR_HEAD
    const char *data[1];
} MyObject;

static PyTypeObject MyObject_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "mymod.MyObject",
    .tp_basicsize = sizeof(MyObject) - sizeof(char *),
    .tp_itemsize = sizeof(char *),
};

순환 가비지 수집 지원

순환 참조를 포함하는 가비지를 탐지하고 수집하는 파이썬의 지원은 역시 컨테이너일 수 있는 다른 객체의 “컨테이너” 인 객체 형의 지원이 필요합니다. 다른 객체에 대한 참조를 저장하지 않거나, 원자 형(가령 숫자나 문자열)에 대한 참조만 저장하는 형은 가비지 수집에 대한 어떤 명시적인 지원을 제공할 필요가 없습니다.

To create a container type, the tp_flags field of the type object must include the Py_TPFLAGS_HAVE_GC and provide an implementation of the tp_traverse handler. If instances of the type are mutable, a tp_clear implementation must also be provided.

Py_TPFLAGS_HAVE_GC

이 플래그가 설정된 형의 객체는 여기에 설명된 규칙을 준수해야 합니다. 편의를 위해 이러한 객체를 컨테이너 객체라고 하겠습니다.

컨테이너형의 생성자는 두 가지 규칙을 준수해야 합니다:

The memory for the object must be allocated using PyObject_GC_New or PyObject_GC_NewVar.

다른 컨테이너에 대한 참조를 포함할 수 있는 모든 필드가 초기화되면, PyObject_GC_Track()를 호출해야 합니다.

마찬가지로, 객체의 할당해제자(deallocator)는 비슷한 규칙 쌍을 준수해야 합니다:

다른 컨테이너를 참조하는 필드가 무효화 되기 전에, PyObject_GC_UnTrack()를 호출해야 합니다.

객체의 메모리는 PyObject_GC_Del()를 사용하여 할당 해제되어야 합니다.

경고

If a type adds the Py_TPFLAGS_HAVE_GC, then it must implement at least a tp_traverse handler or explicitly use one from its subclass or subclasses.

When calling PyType_Ready() or some of the APIs that indirectly call it like PyType_FromSpecWithBases() or PyType_FromSpec() the interpreter will automatically populate the tp_flags, tp_traverse and tp_clear fields if the type inherits from a class that implements the garbage collector protocol and the child class does not include the Py_TPFLAGS_HAVE_GC flag.

PyObject_GC_New(TYPE, typeobj)

Analogous to PyObject_New but for container objects with the Py_TPFLAGS_HAVE_GC flag set.

PyObject_GC_NewVar(TYPE, typeobj, size)

Analogous to PyObject_NewVar but for container objects with the Py_TPFLAGS_HAVE_GC flag set.

PyObject *PyUnstable_Object_GC_NewWithExtraData(PyTypeObject *type, size_t extra_size)

This is Unstable API. It may change without warning in minor releases.

Analogous to PyObject_GC_New but allocates extra_size bytes at the end of the object (at offset tp_basicsize). The allocated memory is initialized to zeros, except for the Python object header.

The extra data will be deallocated with the object, but otherwise it is not managed by Python.

경고

The function is marked as unstable because the final mechanism for reserving extra data after an instance is not yet decided. For allocating a variable number of fields, prefer using PyVarObject and tp_itemsize instead.

Added in version 3.12.

PyObject_GC_Resize(TYPE, op, newsize)

Resize an object allocated by PyObject_NewVar. Returns the resized object of type TYPE* (refers to any C type) or NULL on failure.

op must be of type PyVarObject* and must not be tracked by the collector yet. newsize must be of type Py_ssize_t.

void PyObject_GC_Track(PyObject *op)

Part of the Stable ABI.

수집기가 추적하는 컨테이너 객체 집합에 객체 op를 추가합니다. 수집기는 예기치 않은 시간에 실행될 수 있으므로 추적되는 동안 객체가 유효해야 합니다. tp_traverse 처리기가 탐색하는 모든 필드가 유효해지면 호출해야 합니다, 보통 생성자의 끝부분 근처입니다.

int PyObject_IS_GC(PyObject *obj)

객체가 가비지 수거기 프로토콜을 구현하면 0이 아닌 값을 반환하고, 그렇지 않으면 0을 반환합니다.

이 함수가 0을 반환하면 가비지 수거기가 객체를 추적할 수 없습니다.

int PyObject_GC_IsTracked(PyObject *op)

Part of the Stable ABI since version 3.9.

op의 객체 형이 GC 프로토콜을 구현하고 op가 현재 가비지 수거기가 추적 중이면 1을 반환하고 그렇지 않으면 0을 반환합니다.

이것은 파이썬 함수 gc.is_tracked()에 해당합니다.

Added in version 3.9.

int PyObject_GC_IsFinalized(PyObject *op)

Part of the Stable ABI since version 3.9.

op의 객체 형이 GC 프로토콜을 구현하고 가비지 수거기가 op를 이미 파이널라이즈 했으면 1을 반환하고 그렇지 않으면 0을 반환합니다.

이것은 파이썬 함수 gc.is_finalized()에 해당합니다.

Added in version 3.9.

void PyObject_GC_Del(void *op)

Part of the Stable ABI.

Releases memory allocated to an object using PyObject_GC_New or PyObject_GC_NewVar.

void PyObject_GC_UnTrack(void *op)

Part of the Stable ABI.

수집기가 추적하는 컨테이너 객체 집합에서 op 객체를 제거합니다. PyObject_GC_Track()를 이 객체에 대해 다시 호출하여 추적 객체 집합에 다시 추가할 수 있음에 유의하십시오. 할당해제자(tp_dealloc 처리기)는 tp_traverse 처리기에서 사용하는 필드가 무효화 되기 전에 객체에 대해 이 함수를 호출해야 합니다.

버전 3.8에서 변경: The _PyObject_GC_TRACK() and _PyObject_GC_UNTRACK() macros have been removed from the public C API.

tp_traverse 처리기는 다음과 같은 형의 함수 매개 변수를 받아들입니다:

typedef int (*visitproc)(PyObject *object, void *arg)

Part of the Stable ABI.

tp_traverse 처리기에 전달되는 방문자 함수의 형. 이 함수는 탐색하는 객체를 object로, tp_traverse 처리기의 세 번째 매개 변수를 arg로 호출되어야 합니다. 파이썬 코어는 순환 가비지 탐지를 구현하기 위해 여러 방문자 함수를 사용합니다; 사용자가 자신의 방문자 함수를 작성해야 할 필요는 없습니다.

tp_traverse 처리기는 다음 형이어야 합니다:

typedef int (*traverseproc)(PyObject *self, visitproc visit, void *arg)

Part of the Stable ABI.

컨테이너 객체의 탐색 함수입니다. 구현은 self에 직접 포함된 각 객체에 대해 visit 함수를 호출해야 하며, visit에 대한 매개 변수는 포함된 객체와 처리기로 전달된 arg 값입니다. visit 함수는 NULL object 인자로 호출하면 안 됩니다. visit가 0이 아닌 값을 반환하면 그 값이 즉시 반환되어야 합니다.

tp_traverse 처리기 작성을 단순화하기 위해, Py_VISIT() 매크로가 제공됩니다. 이 매크로를 사용하려면, tp_traverse 구현은 인자의 이름을 정확히 visit 와 arg로 지정해야 합니다:

void Py_VISIT(PyObject *o)

o가 NULL이 아니면, o 와 arg 인자로 visit 콜백을 호출합니다. visit가 0이 아닌 값을 반환하면, 그것을 반환합니다. 이 매크로를 사용하면, tp_traverse 처리기가 다음과 같아집니다:

static int
my_traverse(Noddy *self, visitproc visit, void *arg)
{
    Py_VISIT(self->foo);
    Py_VISIT(self->bar);
    return 0;
}

tp_clear 처리기는 inquiry 형이거나 객체가 불변이면 NULL이어야 합니다.

typedef int (*inquiry)(PyObject *self)

Part of the Stable ABI.

참조 순환을 생성했을 수 있는 참조를 삭제합니다. 불변 객체는 참조 순환을 직접 생성할 수 없으므로, 이 메서드를 정의 할 필요가 없습니다. 이 메서드를 호출한 후에도 객체가 유효해야 합니다 (단지 참조에 대해 Py_DECREF()를 호출하지 마십시오). 이 객체가 참조 순환에 참여하고 있음을 수집기가 감지하면 이 메서드를 호출합니다.

Controlling the Garbage Collector State

The C-API provides the following functions for controlling garbage collection runs.

Py_ssize_t PyGC_Collect(void)

Part of the Stable ABI.

Perform a full garbage collection, if the garbage collector is enabled. (Note that gc.collect() runs it unconditionally.)

Returns the number of collected + unreachable objects which cannot be collected. If the garbage collector is disabled or already collecting, returns 0 immediately. Errors during garbage collection are passed to sys.unraisablehook. This function does not raise exceptions.

int PyGC_Enable(void)

Part of the Stable ABI since version 3.10.

Enable the garbage collector: similar to gc.enable(). Returns the previous state, 0 for disabled and 1 for enabled.

Added in version 3.10.

int PyGC_Disable(void)

Part of the Stable ABI since version 3.10.

Disable the garbage collector: similar to gc.disable(). Returns the previous state, 0 for disabled and 1 for enabled.

Added in version 3.10.

int PyGC_IsEnabled(void)

Part of the Stable ABI since version 3.10.

Query the state of the garbage collector: similar to gc.isenabled(). Returns the current state, 0 for disabled and 1 for enabled.

Added in version 3.10.

Querying Garbage Collector State

The C-API provides the following interface for querying information about the garbage collector.

void PyUnstable_GC_VisitObjects(gcvisitobjects_t callback, void *arg)

This is Unstable API. It may change without warning in minor releases.

Run supplied callback on all live GC-capable objects. arg is passed through to all invocations of callback.

경고

If new objects are (de)allocated by the callback it is undefined if they will be visited.

Garbage collection is disabled during operation. Explicitly running a collection in the callback may lead to undefined behaviour e.g. visiting the same objects multiple times or not at all.

Added in version 3.12.

typedef int (*gcvisitobjects_t)(PyObject *object, void *arg)

Type of the visitor function to be passed to PyUnstable_GC_VisitObjects(). arg is the same as the arg passed to PyUnstable_GC_VisitObjects. Return 0 to continue iteration, return 1 to stop iteration. Other return values are reserved for now so behavior on returning anything else is undefined.

Added in version 3.12.

API와 ABI 버전 붙이기

CPython exposes its version number in the following macros. Note that these correspond to the version code is built with, not necessarily the version used at run time.

See C API Stability for a discussion of API and ABI stability across versions.

PY_MAJOR_VERSION

The 3 in 3.4.1a2.

PY_MINOR_VERSION

The 4 in 3.4.1a2.

PY_MICRO_VERSION

The 1 in 3.4.1a2.

PY_RELEASE_LEVEL

The a in 3.4.1a2. This can be 0xA for alpha, 0xB for beta, 0xC for release candidate or 0xF for final.

PY_RELEASE_SERIAL

The 2 in 3.4.1a2. Zero for final releases.

PY_VERSION_HEX

The Python version number encoded in a single integer.

The underlying version information can be found by treating it as a 32 bit number in the following manner:

바이트

비트 (빅 엔디안 순서)

뜻

Value for 3.4.1a2

1

1-8

PY_MAJOR_VERSION

0x03

2

9-16

PY_MINOR_VERSION

0x04

3

17-24

PY_MICRO_VERSION

0x01

4

25-28

PY_RELEASE_LEVEL

0xA

29-32

PY_RELEASE_SERIAL

0x2

Thus 3.4.1a2 is hexversion 0x030401a2 and 3.10.0 is hexversion 0x030a00f0.

Use this for numeric comparisons, e.g. #if PY_VERSION_HEX >= ....

This version is also available via the symbol Py_Version.

const unsigned long Py_Version

Part of the Stable ABI since version 3.11.

The Python runtime version number encoded in a single constant integer, with the same format as the PY_VERSION_HEX macro. This contains the Python version used at run time.

Added in version 3.11.

모든 주어진 매크로는 Include/patchlevel.h [https://github.com/python/cpython/tree/main/Include/patchlevel.h]에 정의됩니다.

Monitoring C API

Added in version 3.13.

An extension may need to interact with the event monitoring system. Subscribing to events and registering callbacks can be done via the Python API exposed in sys.monitoring.

Generating Execution Events

The functions below make it possible for an extension to fire monitoring events as it emulates the execution of Python code. Each of these functions accepts a PyMonitoringState struct which contains concise information about the activation state of events, as well as the event arguments, which include a PyObject* representing the code object, the instruction offset and sometimes additional, event-specific arguments (see sys.monitoring for details about the signatures of the different event callbacks). The codelike argument should be an instance of types.CodeType or of a type that emulates it.

The VM disables tracing when firing an event, so there is no need for user code to do that.

Monitoring functions should not be called with an exception set, except those listed below as working with the current exception.

type PyMonitoringState

Representation of the state of an event type. It is allocated by the user while its contents are maintained by the monitoring API functions described below.

All of the functions below return 0 on success and -1 (with an exception set) on error.

See sys.monitoring for descriptions of the events.

int PyMonitoring_FirePyStartEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a PY_START event.

int PyMonitoring_FirePyResumeEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a PY_RESUME event.

int PyMonitoring_FirePyReturnEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *retval)

Fire a PY_RETURN event.

int PyMonitoring_FirePyYieldEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *retval)

Fire a PY_YIELD event.

int PyMonitoring_FireCallEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *callable, PyObject *arg0)

Fire a CALL event.

int PyMonitoring_FireLineEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, int lineno)

Fire a LINE event.

int PyMonitoring_FireJumpEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *target_offset)

Fire a JUMP event.

int PyMonitoring_FireBranchEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *target_offset)

Fire a BRANCH event.

int PyMonitoring_FireCReturnEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *retval)

Fire a C_RETURN event.

int PyMonitoring_FirePyThrowEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a PY_THROW event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FireRaiseEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a RAISE event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FireCRaiseEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a C_RAISE event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FireReraiseEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a RERAISE event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FireExceptionHandledEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire an EXCEPTION_HANDLED event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FirePyUnwindEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset)

Fire a PY_UNWIND event with the current exception (as returned by PyErr_GetRaisedException()).

int PyMonitoring_FireStopIterationEvent(PyMonitoringState *state, PyObject *codelike, int32_t offset, PyObject *value)

Fire a STOP_ITERATION event. If value is an instance of StopIteration, it is used. Otherwise, a new StopIteration instance is created with value as its argument.

Managing the Monitoring State

Monitoring states can be managed with the help of monitoring scopes. A scope would typically correspond to a python function.

int PyMonitoring_EnterScope(PyMonitoringState *state_array, uint64_t *version, const uint8_t *event_types, Py_ssize_t length)

Enter a monitored scope. event_types is an array of the event IDs for events that may be fired from the scope. For example, the ID of a PY_START event is the value PY_MONITORING_EVENT_PY_START, which is numerically equal to the base-2 logarithm of sys.monitoring.events.PY_START. state_array is an array with a monitoring state entry for each event in event_types, it is allocated by the user but populated by PyMonitoring_EnterScope() with information about the activation state of the event. The size of event_types (and hence also of state_array) is given in length.

The version argument is a pointer to a value which should be allocated by the user together with state_array and initialized to 0, and then set only by PyMonitoring_EnterScope() itself. It allows this function to determine whether event states have changed since the previous call, and to return quickly if they have not.

The scopes referred to here are lexical scopes: a function, class or method. PyMonitoring_EnterScope() should be called whenever the lexical scope is entered. Scopes can be reentered, reusing the same state_array and version, in situations like when emulating a recursive Python function. When a code-like’s execution is paused, such as when emulating a generator, the scope needs to be exited and re-entered.

The macros for event_types are:

Macro

Event

PY_MONITORING_EVENT_BRANCH

BRANCH

PY_MONITORING_EVENT_CALL

CALL

PY_MONITORING_EVENT_C_RAISE

C_RAISE

PY_MONITORING_EVENT_C_RETURN

C_RETURN

PY_MONITORING_EVENT_EXCEPTION_HANDLED

EXCEPTION_HANDLED

PY_MONITORING_EVENT_INSTRUCTION

INSTRUCTION

PY_MONITORING_EVENT_JUMP

JUMP

PY_MONITORING_EVENT_LINE

LINE

PY_MONITORING_EVENT_PY_RESUME

PY_RESUME

PY_MONITORING_EVENT_PY_RETURN

PY_RETURN

PY_MONITORING_EVENT_PY_START

PY_START

PY_MONITORING_EVENT_PY_THROW

PY_THROW

PY_MONITORING_EVENT_PY_UNWIND

PY_UNWIND

PY_MONITORING_EVENT_PY_YIELD

PY_YIELD

PY_MONITORING_EVENT_RAISE

RAISE

PY_MONITORING_EVENT_RERAISE

RERAISE

PY_MONITORING_EVENT_STOP_ITERATION

STOP_ITERATION

int PyMonitoring_ExitScope(void)

Exit the last scope that was entered with PyMonitoring_EnterScope().

파이썬 모듈 설치하기

전자 우편:

distutils-sig@python.org

널리 사용되는 공개 소스 개발 프로젝트로서, 파이썬에는 적극적으로 지원하는 기여자와 사용자의 커뮤니티가 있어, 자신들의 소프트웨어를 공개 소스 라이센스 계약에 따라 다른 파이썬 개발자가 사용할 수 있도록 합니다.

이를 통해 파이썬 사용자는 효과적으로 공유하고 공동 작업할 수 있으며, 다른 사람들이 공통 (심지어 때로는 희귀한) 문제에 대해 이미 만든 솔루션의 이점을 누릴 수 있을 뿐 아니라, 자체 솔루션을 공동 풀에 잠재적으로 제공할 수 있습니다.

This guide covers the installation part of the process. For a guide to creating and sharing your own Python projects, refer to the Python packaging user guide [https://packaging.python.org/en/latest/tutorials/packaging-projects/].

참고

기업 및 기타 기관 사용자의 경우, 많은 조직에서 공개 소스 소프트웨어를 사용하고 공헌하는 데 대한 자체 정책을 시행하고 있음을 알고 있어야 합니다. 파이썬과 함께 제공되는 배포 및 설치 도구를 사용할 때 이러한 정책을 고려하십시오.

핵심 용어

pip 는 선호되는 설치 프로그램입니다. 파이썬 3.4부터, 기본적으로 파이썬 바이너리 설치 프로그램에 포함되어 있습니다.

가상 환경 은 패키지가 시스템 전체에 설치되는 것이 아니라, 특정 응용 프로그램에 사용되도록 설치될 수 있도록 하는 반 격리 된 파이썬 환경입니다.

venv 는 가상 환경을 만들기 위한 표준 도구이며, 파이썬 3.3 이후로 파이썬의 일부입니다. 파이썬 3.4부터, 생성되는 모든 가상 환경에 기본적으로 pip 를 설치합니다.

virtualenv 는 venv 에 대한 제삼자 대안(그리고 전임자)입니다. venv 를 아예 제공하지 않거나, 생성되는 환경에 pip 를 자동으로 설치할 수 없는, 3.4 이전의 파이썬 버전에서 가상 환경을 사용할 수 있도록 합니다.

The Python Package Index [https://pypi.org] is a public repository of open source licensed packages made available for use by other Python users.

the Python Packaging Authority [https://www.pypa.io/] is the group of developers and documentation authors responsible for the maintenance and evolution of the standard packaging tools and the associated metadata and file format standards. They maintain a variety of tools, documentation, and issue trackers on GitHub [https://github.com/pypa].

distutils 는 1998년에 파이썬 표준 라이브러리에 처음 추가된 최초의 빌드 및 배포 시스템입니다. distutils 의 직접 사용이 단계적으로 폐지되고 있지만, 여전히 현재의 패키징 및 배포 기반 시설의 기초를 이루고 있고, 표준 라이브러리의 일부로 남아있을 뿐만 아니라, 그 이름은 다른 방식으로도 (가령 파이썬 패키징 표준 개발을 조정하는 데 사용되는 메일링 리스트의 이름으로) 남아있습니다.

버전 3.5에서 변경: 이제 가상 환경을 만드는데 venv 사용을 권장합니다.

더 보기

파이썬 패키징 사용자 지침서: 가상 환경 생성과 사용 [https://packaging.python.org/installing/#creating-virtual-environments]

기본 사용법

표준 패키징 도구는 모두 명령 줄에서 사용하도록 설계되었습니다.

The following command will install the latest version of a module and its dependencies from the Python Package Index:

python -m pip install SomePackage

참고

For POSIX users (including macOS and Linux users), the examples in this guide assume the use of a virtual environment.

윈도우 사용자의 경우, 이 지침서의 예제는 파이썬을 설치할 때 시스템 PATH 환경 변수를 조정하는 옵션이 선택되었다고 가정합니다.

정확한 버전이나 최소 버전을 명령 줄에서 직접 지정할 수도 있습니다. >, < 와 같은 비교 연산자나 셸에서 해석되는 다른 특수 문자를 사용할 때는, 패키지 이름과 버전을 큰따옴표로 묶어야 합니다:

python -m pip install SomePackage==1.0.4    # specific version
python -m pip install "SomePackage>=1.0.4"  # minimum version

일반적으로, 적절한 모듈이 이미 설치되어있으면, 다시 설치하려고 해도 아무런 효과가 없습니다. 기존 모듈을 업그레이드하려면 명시적으로 요청해야 합니다:

python -m pip install --upgrade SomePackage

pip 와 그 기능에 관한 더 많은 정보와 자원은 파이썬 패키징 사용자 지침서 [https://packaging.python.org] 에서 찾을 수 있습니다.

가상 환경의 생성은 venv 모듈을 통해 수행됩니다. 활성 가상 환경에 패키지를 설치하려면 위에 표시된 명령을 사용합니다.

더 보기

파이썬 패키징 사용자 지침서: 파이썬 배포 패키지 설치하기 [https://packaging.python.org/installing/]

어떻게 …?

이것들은 몇 가지 일반적인 작업에 대한 빠른 답변 또는 링크입니다.

… 파이썬 3.4 이전 버전의 파이썬에서 pip 를 설치합니까?

파이썬은 pip 를 파이썬 3.4에 와서야 포함하기 시작했습니다. 이전 버전의 경우, pip 는 파이썬 패키징 사용자 지침서에 설명된 대로 “부트스트랩(bootstrapped)” 될 필요가 있습니다.

더 보기

파이썬 패키징 사용자 지침서: 패키지 설치 요구 사항 [https://packaging.python.org/installing/#requirements-for-installing-packages]

… 현재 사용자만을 위해 패키지를 설치합니까?

--user 옵션을 python -m pip install 에 넘겨주면 시스템의 모든 사용자가 아닌 현재 사용자를 위해서만 패키지를 설치합니다.

… 과학 계산용 파이썬 패키지를 설치합니까?

많은 과학 계산용 파이썬 패키지는 복잡한 바이너리 의존성을 가지고 있고, 현재 pip 를 사용하여 직접 설치하기가 쉽지 않습니다. 이 시점에서, 사용자가 이 패키지들을 pip 로 설치하려고 시도하는 것보다 다른 방법 [https://packaging.python.org/science/] 으로 설치하는 것이 더 쉬운 경우가 종종 있습니다.

더 보기

파이썬 패키징 사용자 지침서: 과학 계산용 패키지 설치하기 [https://packaging.python.org/science/]

… 병렬로 설치된 여러 버전의 파이썬으로 작업합니까?

On Linux, macOS, and other POSIX systems, use the versioned Python commands in combination with the -m switch to run the appropriate copy of pip:

python2   -m pip install SomePackage  # default Python 2
python2.7 -m pip install SomePackage  # specifically Python 2.7
python3   -m pip install SomePackage  # default Python 3
python3.4 -m pip install SomePackage  # specifically Python 3.4

적절히 버전이 지정된 pip 명령도 제공될 수 있습니다.

윈도우에서는 py 파이썬 실행기를 -m 스위치와 조합해서 사용하십시오:

py -2   -m pip install SomePackage  # default Python 2
py -2.7 -m pip install SomePackage  # specifically Python 2.7
py -3   -m pip install SomePackage  # default Python 3
py -3.4 -m pip install SomePackage  # specifically Python 3.4

흔히 만나는 설치 문제

리눅스에 시스템 파이썬 설치하기

리눅스 시스템에서, 보통 파이썬 설치가 배포 일부로 포함됩니다. 이 파이썬 설치에 설치하려면 시스템에 대한 루트 액세스가 필요하며, pip 를 사용하여 구성 요소가 예기치 않게 업그레이드되면 시스템 패키지 관리자와 시스템의 다른 구성 요소의 작동을 방해할 수 있습니다.

이러한 시스템에서는, pip 로 패키지를 설치할 때 가상 환경이나 사용자별 설치를 사용하는 것이 더 좋습니다.

Pip가 설치되지 않았습니다.

pip 가 기본적으로 설치되지 않았을 수도 있습니다. 한가지 가능한 해결법은 다음과 같습니다:

python -m ensurepip --default-pip

There are also additional resources for installing pip. [https://packaging.python.org/en/latest/tutorials/installing-packages/#ensure-pip-setuptools-and-wheel-are-up-to-date]

바이너리 확장 설치하기

파이썬은 일반적으로 소스 기반 배포에 크게 의존하고 있으며, 최종 사용자가 설치 프로세스의 일부로 소스로부터 확장 모듈을 컴파일할 것으로 기대합니다.

With the introduction of support for the binary wheel format, and the ability to publish wheels for at least Windows and macOS through the Python Package Index, this problem is expected to diminish over time, as users are more regularly able to install pre-built extensions rather than needing to build them themselves.

wheel 파일로 아직 사용할 수 없는 과학 계산용 소프트웨어 [https://packaging.python.org/science/] 설치를 위한 어떤 해결책들은 로컬에서 빌드할 필요 없이 다른 바이너리 확장을 얻는 데 도움이 될 수 있습니다.

더 보기

파이썬 패키징 사용자 지침서: 바이너리 확장 [https://packaging.python.org/extensions/]

파이썬 HOWTO

Python HOWTOs are documents that cover a specific topic in-depth. Modeled on the Linux Documentation Project’s HOWTO collection, this collection is an effort to foster documentation that’s more detailed than the Python Library Reference.

General:

Annotations Best Practices

Argparse 자습서

Descriptor Guide

Enum HOWTO

함수형 프로그래밍 HOWTO

ipaddress 모듈에 대한 소개

로깅 HOWTO

로깅 요리책

정규식 HOWTO

Sorting Techniques

유니코드 HOWTO

urllib 패키지를 사용하여 인터넷 리소스를 가져오는 방법

Advanced development:

파이썬 curses 프로그래밍

Python experimental support for free threading

C API Extension Support for Free Threading

Isolating Extension Modules

The Python 2.3 Method Resolution Order

소켓 프로그래밍 HOWTO

timer file descriptor HOWTO

확장 모듈을 파이썬 3에 이식하기

Debugging and profiling:

Debugging C API extensions and CPython Internals with GDB

DTrace와 SystemTap으로 CPython 계측하기

Python support for the Linux perf profiler

확장 모듈을 파이썬 3에 이식하기

확장 모듈을 파이썬 3에 이식하는 것에 관해서는 다음과 같은 리소스를 추천합니다:

파이썬 2에서 파이썬 3으로 옮겨가는 것에 관한 일반적인 책인 Supporting Python 3: An in-depth guide의 Migrating C extensions [http://python3porting.com/cextensions.html] 장은 독자에게 확장 모듈을 이식하는 과정을 안내합니다.

py3c 프로젝트의 Porting guide [https://py3c.readthedocs.io/en/latest/guide.html]는 지원 코드와 함께 전문적인 제안을 제공합니다.

Cython [https://cython.org/]과 CFFI [https://cffi.readthedocs.io/en/latest/] 라이브러리는 파이썬의 C API에 대한 추상화를 제공합니다. 이들을 사용하려면 일반적으로 확장을 재작성할 필요가 있지만, 그런 다음에는 라이브러리가 다양한 파이썬 버전과 구현 간의 차이점을 처리합니다.

파이썬 curses 프로그래밍

저자:

A.M. Kuchling, Eric S. Raymond

버전:

2.04

요약

이 문서는 curses 확장 모듈을 사용하여 텍스트 모드 디스플레이를 제어하는 방법을 설명합니다.

curses란 무엇입니까?

curses 라이브러리는 텍스트 기반 터미널을 위한 터미널 독립적인 스크린 페인팅과 키보드 처리 기능을 제공합니다; 이러한 터미널에는 VT100, 리눅스 콘솔 및 다양한 프로그램에서 제공하는 시뮬레이트 된 터미널이 포함됩니다. 디스플레이 터미널은 커서 이동, 화면 스크롤 및 영역 지우기와 같은 일반적인 작업을 수행하기 위해 다양한 제어 코드를 지원합니다. 터미널마다 서로 다른 코드를 사용하며 종종 자신만의 사소한 문제가 있습니다.

그래픽 디스플레이의 세계에서, 이렇게 물을 수 있습니다. “왜 신경 써야 하나요”? 문자 셀 디스플레이 터미널은 한물간 기술이지만, 사실 여전히 가치 있는 멋진 작업을 수행할 수 있는 틈새가 존재합니다. 한가지 틈새는 X 서버를 실행하지 않는 작은 크기 혹은 내장 유닉스입니다. 다른 것으로는 그래픽 지원을 사용할 수 있기 전에 실행해야 할 OS 설치 프로그램과 커널 구성기와 같은 도구가 있습니다.

The curses library provides fairly basic functionality, providing the programmer with an abstraction of a display containing multiple non-overlapping windows of text. The contents of a window can be changed in various ways—adding text, erasing it, changing its appearance—and the curses library will figure out what control codes need to be sent to the terminal to produce the right output. curses doesn’t provide many user-interface concepts such as buttons, checkboxes, or dialogs; if you need such features, consider a user interface library such as Urwid [https://pypi.org/project/Urwid/].

curses 라이브러리는 원래 BSD 유닉스용으로 작성되었습니다; 그 이후 AT&T의 유닉스 시스템 V 버전에는 많은 개선 사항과 새로운 기능이 추가되었습니다. BSD curses는 더는 유지되지 않고, AT&T 인터페이스의 오픈 소스 구현인 ncurses로 대체되었습니다. 리눅스나 FreeBSD 와 같은 오픈 소스 유닉스를 사용하고 있다면, 시스템은 거의 확실히 ncurses를 사용합니다. 최신 상용 유닉스 버전은 대부분 시스템 V 코드를 기반으로 하므로, 여기에 설명된 모든 기능을 아마도 사용할 수 있을 것입니다. 그러나 일부 독점적 유닉스가 제공하는 이전 버전의 curses는 모든 것을 지원하지 않을 수 있습니다.

The Windows version of Python doesn’t include the curses module. A ported version called UniCurses [https://pypi.org/project/UniCurses/] is available.

파이썬 curses 모듈

The Python module is a fairly simple wrapper over the C functions provided by curses; if you’re already familiar with curses programming in C, it’s really easy to transfer that knowledge to Python. The biggest difference is that the Python interface makes things simpler by merging different C functions such as addstr(), mvaddstr(), and mvwaddstr() into a single addstr() method. You’ll see this covered in more detail later.

이 HOWTO는 curses와 파이썬으로 텍스트 모드 프로그램을 작성하는 방법을 소개합니다. curses API에 대한 완전한 안내서가 되려는 것은 아닙니다; 그것을 위해서는 ncurses에 대한 파이썬 라이브러리 안내서 섹션과 ncurses에 대한 C 매뉴얼 페이지를 참조하십시오. 그러나 기본 아이디어는 제공합니다.

curses 응용 프로그램 시작과 종료

Before doing anything, curses must be initialized. This is done by calling the initscr() function, which will determine the terminal type, send any required setup codes to the terminal, and create various internal data structures. If successful, initscr() returns a window object representing the entire screen; this is usually called stdscr after the name of the corresponding C variable.

import curses
stdscr = curses.initscr()

일반적으로 curses 응용 프로그램은 키를 읽고 특정 상황에서만 표시할 수 있도록 화면으로 키를 자동 에코 하는 기능을 끕니다. 이를 위해서는 noecho() 함수를 호출해야 합니다.

curses.noecho()

응용 프로그램은 또한 일반적으로 Enter 키를 누르지 않아도 즉시 키에 반응해야 합니다; 이것을 일반적인 버퍼 입력 모드와 대비하여 cbreak 모드라고 합니다.

curses.cbreak()

터미널은 일반적으로 커서 키나 Page Up, Home 등의 탐색 키와 같은 특수 키를 멀티 바이트 이스케이프 시퀀스로 반환합니다. 이러한 시퀀스를 예상하고 적절하게 처리하도록 응용 프로그램을 작성할 수는 있지만, curses가 이를 수행하여 curses.KEY_LEFT와 같은 특수 값을 반환할 수 있습니다. curses가 이런 일을 하도록 하려면, 키패드 모드를 활성화해야 합니다.

stdscr.keypad(True)

curses 응용 프로그램을 종료하는 것은 시작하기보다 훨씬 쉽습니다. 다음과 같이 호출합니다:

curses.nocbreak()
stdscr.keypad(False)
curses.echo()

curses 친화적인 터미널 설정을 되돌립니다. 그런 다음 endwin() 함수를 호출하여 터미널을 원래 작동 모드로 복원하십시오.

curses.endwin()

curses 응용 프로그램을 디버깅할 때 일반적인 문제점은 터미널을 이전 상태로 복원하지 않고 응용 프로그램이 죽을 때 터미널이 엉망이 되는 것입니다. 파이썬에서 코드에 버그가 있고 잡히지 않는 예외를 일으킬 때 흔히 일어납니다. 예를 들어, 키를 입력해도 키가 더는 화면에 표시되지 않아 셸 사용이 어려워집니다.

파이썬에서는 curses.wrapper() 함수를 임포트하고 다음과 같이 사용하여 이러한 복잡성을 피하고 디버깅을 훨씬 쉽게 할 수 있습니다:

from curses import wrapper

def main(stdscr):
    # Clear screen
    stdscr.clear()

    # This raises ZeroDivisionError when i == 10.
    for i in range(0, 11):
        v = i-10
        stdscr.addstr(i, 0, '10 divided by {} is {}'.format(v, 10/v))

    stdscr.refresh()
    stdscr.getkey()

wrapper(main)

The wrapper() function takes a callable object and does the initializations described above, also initializing colors if color support is present. wrapper() then runs your provided callable. Once the callable returns, wrapper() will restore the original state of the terminal. The callable is called inside a try…except that catches exceptions, restores the state of the terminal, and then re-raises the exception. Therefore your terminal won’t be left in a funny state on exception and you’ll be able to read the exception’s message and traceback.

창과 패드

창은 curses의 기본 추상화입니다. 창 객체는 화면의 사각형 영역을 나타내며, 텍스트를 표시하고, 지우고, 사용자가 문자열을 입력할 수 있도록 하는 등의 메서드를 지원합니다.

initscr() 함수가 반환한 stdscr 객체는 전체 화면을 덮는 창 객체입니다. 많은 프로그램에서 이 창 하나만 필요할 수도 있지만, 따로 다시 그리거나 지우기 위해 화면을 작은 창으로 나누고 싶을 수 있습니다. newwin() 함수는 지정된 크기의 새 창을 만들어 새 창 객체를 반환합니다.

begin_x = 20; begin_y = 7
height = 5; width = 40
win = curses.newwin(height, width, begin_y, begin_x)

curses에 사용된 좌표계는 일반적이지 않음에 주의하십시오. 좌표는 항상 y,x 순서로 전달되며, 창의 왼쪽 상단 모서리는 좌표 (0,0) 입니다. 이것은 x 좌표가 먼저 오는, 좌표를 다루는 일반적인 규칙을 위반합니다. 이것은 대부분 다른 컴퓨터 응용 프로그램과의 불행한 차이점이지만, 처음 작성된 이후로 curses 일부였으며, 지금 되돌리기에는 너무 늦었습니다.

응용 프로그램은 y와 x 크기를 얻기 위해 curses.LINES와 curses.COLS 변수를 사용하여 화면 크기를 결정할 수 있습니다. 그러면 유효한 좌표는 (0,0)에서 (curses.LINES - 1, curses.COLS - 1)에 이릅니다.

텍스트를 표시하거나 지우기 위해 메서드를 호출할 때, 효과는 즉시 디스플레이에 나타나지 않습니다. 대신 화면을 갱신하기 위해 창 객체의 refresh() 메서드를 호출해야 합니다.

This is because curses was originally written with slow 300-baud terminal connections in mind; with these terminals, minimizing the time required to redraw the screen was very important. Instead curses accumulates changes to the screen and displays them in the most efficient manner when you call refresh(). For example, if your program displays some text in a window and then clears the window, there’s no need to send the original text because they’re never visible.

In practice, explicitly telling curses to redraw a window doesn’t really complicate programming with curses much. Most programs go into a flurry of activity, and then pause waiting for a keypress or some other action on the part of the user. All you have to do is to be sure that the screen has been redrawn before pausing to wait for user input, by first calling stdscr.refresh() or the refresh() method of some other relevant window.

패드(pad)는 창의 특별한 경우입니다; 실제 디스플레이 화면보다 클 수 있으며, 한 번에 패드의 일부만 표시될 수 있습니다. 패드를 만들려면 패드의 높이와 너비가 필요하지만, 패드를 새로 고치려면 패드의 서브 섹션이 표시될 화면 영역의 좌표를 지정해야 합니다.

pad = curses.newpad(100, 100)
# These loops fill the pad with letters; addch() is
# explained in the next section
for y in range(0, 99):
    for x in range(0, 99):
        pad.addch(y,x, ord('a') + (x*x+y*y) % 26)

# Displays a section of the pad in the middle of the screen.
# (0,0) : coordinate of upper-left corner of pad area to display.
# (5,5) : coordinate of upper-left corner of window area to be filled
#         with pad content.
# (20, 75) : coordinate of lower-right corner of window area to be
#          : filled with pad content.
pad.refresh( 0,0, 5,5, 20,75)

The refresh() call displays a section of the pad in the rectangle extending from coordinate (5,5) to coordinate (20,75) on the screen; the upper left corner of the displayed section is coordinate (0,0) on the pad. Beyond that difference, pads are exactly like ordinary windows and support the same methods.

If you have multiple windows and pads on screen there is a more efficient way to update the screen and prevent annoying screen flicker as each part of the screen gets updated. refresh() actually does two things:

각 창의 noutrefresh() 메서드를 호출하여 원하는 화면 상태를 나타내는 하부 데이터 구조를 갱신합니다.

doupdate() 함수를 호출하여 데이터 구조에 기록된 원하는 상태와 일치하도록 물리적 화면을 변경합니다.

Instead you can call noutrefresh() on a number of windows to update the data structure, and then call doupdate() to update the screen.

텍스트 표시

From a C programmer’s point of view, curses may sometimes look like a twisty maze of functions, all subtly different. For example, addstr() displays a string at the current cursor location in the stdscr window, while mvaddstr() moves to a given y,x coordinate first before displaying the string. waddstr() is just like addstr(), but allows specifying a window to use instead of using stdscr by default. mvwaddstr() allows specifying both a window and a coordinate.

다행히 파이썬 인터페이스는 이러한 모든 세부 사항을 숨깁니다. stdscr은 다른 것과 마찬가지로 창 객체이며, addstr()과 같은 메서드는 여러 인자 형식을 허용합니다. 일반적으로 네 가지 형식이 있습니다.

형식

설명

str 또는 ch

현재 위치에 문자열 str이나 문자 ch를 표시합니다

str 또는 ch, attr

현재 위치에 속성 attr을 사용하여 문자열 str이나 문자 ch를 표시합니다

y, x, str 또는 ch

창에서 y,x 위치로 이동하고, str이나 ch를 표시합니다

y, x, str 또는 ch, attr

창에서 y,x 위치로 이동하고, attr 속성을 사용하여 str이나 ch를 표시합니다

속성을 사용하면 굵은 체, 밑줄, 반전 코드 또는 색상과 같은 강조 표시된 형태로 텍스트를 표시할 수 있습니다. 이에 대해서는 다음 서브 섹션에서 자세히 설명합니다.

The addstr() method takes a Python string or bytestring as the value to be displayed. The contents of bytestrings are sent to the terminal as-is. Strings are encoded to bytes using the value of the window’s encoding attribute; this defaults to the default system encoding as returned by locale.getencoding().

addch() 메서드는 길이가 1인 문자열, 길이가 1인 바이트열 또는 정수일 수 있는 문자를 취합니다.

확장 문자를 위한 상수가 제공됩니다; 이 상수는 255보다 큰 정수입니다. 예를 들어, ACS_PLMINUS는 +/- 기호이고, ACS_ULCORNER는 상자의 왼쪽 위 모서리입니다 (경계를 그리기에 편리합니다). 적절한 유니코드 문자를 사용할 수도 있습니다.

창은 마지막 조작 후 커서가 있던 위치를 기억하므로, y,x 좌표를 생략하면 마지막 조작이 중단된 위치에 문자열이나 문자가 표시됩니다. move(y,x) 메서드로 커서를 이동할 수도 있습니다. 일부 터미널은 항상 깜빡이는 커서를 표시하기 때문에, 방해받지 않는 위치에 커서를 놓아야 합니다; 임의의 위치에서 커서가 깜박이는 것은 혼란스러울 수 있습니다.

응용 프로그램에 깜박이는 커서가 전혀 필요하지 않으면, curs_set(False)를 호출하여 보이지 않게 할 수 있습니다. 이전 curses 버전과의 호환성을 위해, curs_set()과 동의어인 leaveok(bool) 함수가 있습니다. bool 이 참이면, curses 라이브러리는 깜박이는 커서를 억제하려고 시도하고, 커서를 부적절한 위치에 두는 것에 대해 걱정할 필요가 없습니다.

속성과 색상

문자는 다른 방식으로 표시될 수 있습니다. 텍스트 기반 응용 프로그램의 상태 줄(status line)은 일반적으로 반전 비디오로 표시되거나 텍스트 뷰어에서 특정 단어를 강조 표시해야 할 수 있습니다. curses는 화면에 있는 각 셀의 속성을 지정할 수 있도록 하여 이를 지원합니다.

속성은 정수이며, 각 비트는 다른 속성을 나타냅니다. 여러 속성 비트가 설정된 텍스트를 표시하려고 시도 할 수 있지만, curses는 가능한 모든 조합을 사용할 수 있거나 시각적으로 구별됨을 보증하지 않습니다. 사용하는 터미널의 기능에 따라 다르므로, 여기에 나열된 가장 일반적으로 사용 가능한 속성을 고수하는 것이 가장 안전합니다.

속성

설명

A_BLINK

깜박거리는 텍스트

A_BOLD

매우 밝거나 굵은 텍스트

A_DIM

절반 밝기의 텍스트

A_REVERSE

반전 비디오 텍스트

A_STANDOUT

사용 가능한 최고 강조 표시 모드

A_UNDERLINE

밑줄이 그어진 텍스트

따라서 화면 상단 줄에 반전 비디오 상태 줄을 표시하려면, 다음과 같이 코딩할 수 있습니다:

stdscr.addstr(0, 0, "Current mode: Typing mode",
              curses.A_REVERSE)
stdscr.refresh()

curses 라이브러리는 또한 색상을 제공하는 터미널에서 색상을 지원합니다. 이러한 터미널 중 가장 일반적인 터미널은 리눅스 콘솔이고, 그다음은 컬러 xterm입니다.

색상을 사용하려면, initscr()을 호출한 직후 start_color() 함수를 호출하여, 기본 색상 집합을 초기화해야 합니다 (curses.wrapper() 함수는 이것을 자동으로 수행합니다). 일단 이렇게 하면, has_colors() 함수는 사용 중인 터미널이 실제로 색상을 표시할 수 있으면 True를 반환합니다. (참고: curses는 캐나다/영국 철자법 ‘colour’ 대신 미국식 철자법 ‘color’를 사용합니다. 영국 철자법에 익숙하다면 이러한 함수를 위해 철자법을 바꾸는 것을 감수해야 합니다.)

curses 라이브러리는 전경(또는 텍스트)색과 배경색을 포함하여 유한한 수의 색 쌍을 유지합니다. color_pair() 함수를 사용하여 색상 쌍에 해당하는 속성값을 얻을 수 있습니다; 이것은 A_REVERSE와 같은 다른 속성과 비트별 OR 될 수 있지만, 다시 한번, 이러한 조합이 모든 터미널에서 작동하는 것은 아닙니다.

색상 쌍 1을 사용하여 텍스트 줄을 표시하는 예:

stdscr.addstr("Pretty text", curses.color_pair(1))
stdscr.refresh()

앞에서 말했듯이, 색상 쌍은 전경색과 배경색으로 구성됩니다. init_pair(n, f, b) 함수는 색상 쌍 n의 정의를 전경색 f와 배경색 b로 변경합니다. 색상 쌍 0은 검은 배경에 흰 전경으로 강제되어 있으며 변경할 수 없습니다.

색상은 번호가 매겨지며, start_color()는 색상 모드를 활성화할 때 8가지 기본 색상을 초기화합니다. 0:검정(black), 1:빨강(red), 2:녹색(green), 3:노랑(yellow), 4:파랑(blue), 5:자홍색(magenta), 6:청록색(cyan) 및 7:하양(white) 입니다. curses 모듈은 curses.COLOR_BLACK, curses.COLOR_RED 등 각 색상에 대해 이름 붙인 상수를 정의합니다.

이 모든 것을 써봅시다. 색상 1을 흰색 배경의 빨간색 텍스트로 변경하려면, 다음과 같이 호출할 수 있습니다:

curses.init_pair(1, curses.COLOR_RED, curses.COLOR_WHITE)

색상 쌍을 변경할 때, 해당 색상 쌍을 사용하여 이미 표시된 텍스트가 새 색상으로 변경됩니다. 이 색상으로 새 텍스트를 표시 할 수도 있습니다:

stdscr.addstr(0,0, "RED ALERT!", curses.color_pair(1))

매우 멋진 터미널은 실제 색상의 정의를 주어진 RGB 값으로 변경할 수 있습니다. 이를 통해 일반적으로 빨간색인 색상 1을 보라색이나 파란색 또는 원하는 어떤 색상으로도 변경할 수 있습니다. 불행히도, 리눅스 콘솔은 이것을 지원하지 않아서, 저는 시도해 볼 수 없고 예제를 제공할 수 없습니다. can_change_color()를 호출하여 여러분의 터미널이 이를 수행 할 수 있는지를 확인할 수 있습니다. 기능이 있으면 True를 반환합니다. 이러한 재능있는 터미널을 보유할 만큼 운이 좋다면, 자세한 내용은 시스템 매뉴얼 페이지를 참조하십시오.

사용자 입력

The C curses library offers only very simple input mechanisms. Python’s curses module adds a basic text-input widget. (Other libraries such as Urwid [https://pypi.org/project/Urwid/] have more extensive collections of widgets.)

창에서 입력을 얻는 메서드는 두 가지가 있습니다.:

getch()는 화면을 새로 고친 다음 사용자가 키를 누를 때까지 기다립니다. echo()가 이전에 호출되었으면 키를 표시합니다. 일시 정지하기 전에 커서를 이동시킬 좌표를 선택적으로 지정할 수 있습니다.

getkey()는 같은 작업을 수행하지만, 정수를 문자열로 변환합니다. 개별 문자는 1-문자 문자열로 반환되며, 기능 키와 같은 특수키는 KEY_UP이나 ^G와 같은 키 이름을 포함하는 더 긴 문자열을 반환합니다.

It’s possible to not wait for the user using the nodelay() window method. After nodelay(True), getch() and getkey() for the window become non-blocking. To signal that no input is ready, getch() returns curses.ERR (a value of -1) and getkey() raises an exception. There’s also a halfdelay() function, which can be used to (in effect) set a timer on each getch(); if no input becomes available within a specified delay (measured in tenths of a second), curses raises an exception.

The getch() method returns an integer; if it’s between 0 and 255, it represents the ASCII code of the key pressed. Values greater than 255 are special keys such as Page Up, Home, or the cursor keys. You can compare the value returned to constants such as curses.KEY_PPAGE, curses.KEY_HOME, or curses.KEY_LEFT. The main loop of your program may look something like this:

while True:
    c = stdscr.getch()
    if c == ord('p'):
        PrintDocument()
    elif c == ord('q'):
        break  # Exit the while loop
    elif c == curses.KEY_HOME:
        x = y = 0

curses.ascii 모듈은 정수나 1문자 문자열 인자를 취하는 ASCII 클래스 멤버십 함수를 제공합니다; 이러한 루프에서 더 읽기 쉬운 검사를 작성하는 데 유용 할 수 있습니다. 이것은 또한 정수나 1문자 문자열 인자를 취하고 같은 유형을 반환하는 변환 함수를 제공합니다. 예를 들어, curses.ascii.ctrl()은 인자에 해당하는 제어 문자를 반환합니다.

전체 문자열을 꺼내는 메서드도 있습니다, getstr(). 기능이 상당히 제한되어 있기 때문에 자주 사용되지 않습니다; 사용 가능한 편집 키는 백스페이스키와 문자열을 종료하는 Enter 키뿐입니다. 고정된 수의 문자로 선택적으로 제한될 수 있습니다.

curses.echo()            # Enable echoing of characters

# Get a 15-character string, with the cursor on the top line
s = stdscr.getstr(0,0, 15)

curses.textpad 모듈은 Emacs와 같은 키 바인딩 집합을 지원하는 텍스트 상자를 제공합니다. Textbox 클래스의 다양한 메서드는 입력 유효성 검증을 사용한 편집과 후행 공백이 있거나 없는 편집 결과 수집을 지원합니다. 예를 들면 다음과 같습니다:

import curses
from curses.textpad import Textbox, rectangle

def main(stdscr):
    stdscr.addstr(0, 0, "Enter IM message: (hit Ctrl-G to send)")

    editwin = curses.newwin(5,30, 2,1)
    rectangle(stdscr, 1,0, 1+5+1, 1+30+1)
    stdscr.refresh()

    box = Textbox(editwin)

    # Let the user edit until Ctrl-G is struck.
    box.edit()

    # Get resulting contents
    message = box.gather()

자세한 내용은 curses.textpad의 라이브러리 설명서를 참조하십시오.

추가 정보

이 HOWTO는 화면의 내용을 읽거나 xterm 인스턴스에서 마우스 이벤트를 캡처하는 등의 고급 주제를 다루지 않지만, curses 모듈의 파이썬 라이브러리 페이지는 이제 어느 정도 완전합니다. 다음으로 그 페이지를 보십시오.

If you’re in doubt about the detailed behavior of the curses functions, consult the manual pages for your curses implementation, whether it’s ncurses or a proprietary Unix vendor’s. The manual pages will document any quirks, and provide complete lists of all the functions, attributes, and ACS_* characters available to you.

curses API가 아주 크기 때문에, 일부 함수는 파이썬 인터페이스에서 지원되지 않습니다. 종종 구현하기가 어렵기 때문이 아니라, 아직 아무도 원하지 않았기 때문입니다. 또한, 파이썬은 ncurses와 관련된 메뉴 라이브러리를 아직 지원하지 않습니다. 이들에 대한 지원을 추가하는 패치를 환영합니다; 파이썬에 패치를 제출하는 방법에 대한 자세한 내용은 파이썬 개발자 지침서 [https://devguide.python.org/]를 참조하십시오.

Writing Programs with NCURSES [https://invisible-island.net/ncurses/ncurses-intro.html]: a lengthy tutorial for C programmers.

ncurses 매뉴얼 페이지 [https://linux.die.net/man/3/ncurses]

The ncurses FAQ [https://invisible-island.net/ncurses/ncurses.faq.html]

“Use curses… don’t swear” [https://www.youtube.com/watch?v=eN1eZtjLEnU]: curses나 Urwid를 사용하여 터미널을 제어하는 PyCon 2013 발표 비디오.

“Console Applications with Urwid” [https://pyvideo.org/video/1568/console-applications-with-urwid]: video of a PyCon CA 2012 talk demonstrating some applications written using Urwid.

Descriptor Guide

저자:

Raymond Hettinger

연락처:

<python at rcn dot com>

목차

Descriptor Guide

입문

간단한 예: 상수를 반환하는 디스크립터

동적 조회

관리되는 어트리뷰트

사용자 정의 이름

마무리 생각

완전한 실용적인 예

유효성 검사기 클래스

사용자 정의 유효성 검사기

실용적인 응용

기술적인 자습서

요약

정의와 소개

디스크립터 프로토콜

디스크립터 호출의 개요

인스턴스에서 호출

클래스에서 호출

super에서 호출

호출 로직 요약

자동 이름 알림

ORM 예제

순수한 파이썬 등가물

프로퍼티

함수와 메서드

메서드의 종류

정적 메서드

클래스 메서드

멤버 객체와 __slots__

디스크립터는 객체가 어트리뷰트 조회, 저장 및 삭제를 사용자 정의 할 수 있도록 합니다.

이 지침서는 네 개의 주요 섹션으로 구성됩니다:

“입문”은 간단한 예제에서 부드럽게 이동하여 한 번에 하나의 기능을 추가하는 기본 개요를 제공합니다. 디스크립터를 처음 사용하면 여기에서 시작하세요.

두 번째 섹션은 완전하고 실용적인 디스크립터 예제를 보여줍니다. 이미 기본 사항을 알고 있다면, 여기에서 시작하십시오.

세 번째 섹션에서는 디스크립터가 작동하는 방식에 대한 자세한 메커니즘에 관해 설명하는 더 기술적인 자습서를 제공합니다. 대부분의 사람은 이러한 수준의 세부 정보가 필요하지 않습니다.

마지막 섹션에는 C로 작성된 내장 디스크립터에 대한 순수한 파이썬 등가물이 있습니다. 함수가 연결된 메서드로 바뀌는 방법이나 classmethod(), staticmethod(), property() 및 __slots__와 같은 일반적인 도구의 구현에 대해 궁금하면 이 문서를 읽으십시오.

입문

이 입문서에서는, 가능한 가장 기본적인 예제로 시작한 다음 새로운 기능을 하나씩 추가할 것입니다.

간단한 예: 상수를 반환하는 디스크립터

The Ten class is a descriptor whose __get__() method always returns the constant 10:

class Ten:
    def __get__(self, obj, objtype=None):
        return 10

디스크립터를 사용하려면, 다른 클래스에 클래스 변수로 저장해야 합니다:

class A:
    x = 5                       # Regular class attribute
    y = Ten()                   # Descriptor instance

대화 형 세션은 일반 어트리뷰트 조회와 디스크립터 조회의 차이점을 보여줍니다:

>>> a = A()                     # Make an instance of class A
>>> a.x                         # Normal attribute lookup
5
>>> a.y                         # Descriptor lookup
10

In the a.x attribute lookup, the dot operator finds 'x': 5 in the class dictionary. In the a.y lookup, the dot operator finds a descriptor instance, recognized by its __get__ method. Calling that method returns 10.

10 값이 클래스 딕셔너리나 인스턴스 딕셔너리에 저장되지 않음에 유의하십시오. 대신, 10 값은 요청 시 계산됩니다.

이 예는 간단한 디스크립터가 어떻게 작동하는지 보여 주지만, 그다지 유용하지는 않습니다. 상수를 꺼내려면, 일반 어트리뷰트 조회가 더 좋습니다.

다음 섹션에서는, 좀 더 유용한 동적 조회를 만들 것입니다.

동적 조회

흥미로운 디스크립터는 보통 상수를 반환하는 대신 계산을 실행합니다:

import os

class DirectorySize:

    def __get__(self, obj, objtype=None):
        return len(os.listdir(obj.dirname))

class Directory:

    size = DirectorySize()              # Descriptor instance

    def __init__(self, dirname):
        self.dirname = dirname          # Regular instance attribute

대화 형 세션은 조회가 동적임을 보여줍니다 - 매번 다른 갱신된 답변을 계산합니다:

>>> s = Directory('songs')
>>> g = Directory('games')
>>> s.size                              # The songs directory has twenty files
20
>>> g.size                              # The games directory has three files
3
>>> os.remove('games/chess')            # Delete a game
>>> g.size                              # File count is automatically updated
2

Besides showing how descriptors can run computations, this example also reveals the purpose of the parameters to __get__(). The self parameter is size, an instance of DirectorySize. The obj parameter is either g or s, an instance of Directory. It is the obj parameter that lets the __get__() method learn the target directory. The objtype parameter is the class Directory.

관리되는 어트리뷰트

A popular use for descriptors is managing access to instance data. The descriptor is assigned to a public attribute in the class dictionary while the actual data is stored as a private attribute in the instance dictionary. The descriptor’s __get__() and __set__() methods are triggered when the public attribute is accessed.

다음 예에서, age는 공용 어트리뷰트이고 _age는 개인 어트리뷰트입니다. 공용 어트리뷰트에 액세스하면, 디스크립터는 조회나 갱신을 로그 합니다:

import logging

logging.basicConfig(level=logging.INFO)

class LoggedAgeAccess:

    def __get__(self, obj, objtype=None):
        value = obj._age
        logging.info('Accessing %r giving %r', 'age', value)
        return value

    def __set__(self, obj, value):
        logging.info('Updating %r to %r', 'age', value)
        obj._age = value

class Person:

    age = LoggedAgeAccess()             # Descriptor instance

    def __init__(self, name, age):
        self.name = name                # Regular instance attribute
        self.age = age                  # Calls __set__()

    def birthday(self):
        self.age += 1                   # Calls both __get__() and __set__()

대화 형 세션은 관리되는 어트리뷰트 age에 대한 모든 액세스가 로그 되지만, 일반 어트리뷰트 name은 로그 되지 않음을 보여줍니다:

>>> mary = Person('Mary M', 30)         # The initial age update is logged
INFO:root:Updating 'age' to 30
>>> dave = Person('David D', 40)
INFO:root:Updating 'age' to 40

>>> vars(mary)                          # The actual data is in a private attribute
{'name': 'Mary M', '_age': 30}
>>> vars(dave)
{'name': 'David D', '_age': 40}

>>> mary.age                            # Access the data and log the lookup
INFO:root:Accessing 'age' giving 30
30
>>> mary.birthday()                     # Updates are logged as well
INFO:root:Accessing 'age' giving 30
INFO:root:Updating 'age' to 31

>>> dave.name                           # Regular attribute lookup isn't logged
'David D'
>>> dave.age                            # Only the managed attribute is logged
INFO:root:Accessing 'age' giving 40
40

이 예제의 한 가지 주요 문제는 개인 이름 _age가 LoggedAgeAccess 클래스에 고정되어 있다는 것입니다. 즉, 각 인스턴스는 하나의 로그 되는 어트리뷰트 만 가질 수 있으며 해당 이름을 변경할 수 없습니다. 다음 예에서는, 이 문제를 수정합니다.

사용자 정의 이름

클래스가 디스크립터를 사용할 때, 어떤 변수 이름이 사용되었는지 각 디스크립터에 알릴 수 있습니다.

In this example, the Person class has two descriptor instances, name and age. When the Person class is defined, it makes a callback to __set_name__() in LoggedAccess so that the field names can be recorded, giving each descriptor its own public_name and private_name:

import logging

logging.basicConfig(level=logging.INFO)

class LoggedAccess:

    def __set_name__(self, owner, name):
        self.public_name = name
        self.private_name = '_' + name

    def __get__(self, obj, objtype=None):
        value = getattr(obj, self.private_name)
        logging.info('Accessing %r giving %r', self.public_name, value)
        return value

    def __set__(self, obj, value):
        logging.info('Updating %r to %r', self.public_name, value)
        setattr(obj, self.private_name, value)

class Person:

    name = LoggedAccess()                # First descriptor instance
    age = LoggedAccess()                 # Second descriptor instance

    def __init__(self, name, age):
        self.name = name                 # Calls the first descriptor
        self.age = age                   # Calls the second descriptor

    def birthday(self):
        self.age += 1

An interactive session shows that the Person class has called __set_name__() so that the field names would be recorded. Here we call vars() to look up the descriptor without triggering it:

>>> vars(vars(Person)['name'])
{'public_name': 'name', 'private_name': '_name'}
>>> vars(vars(Person)['age'])
{'public_name': 'age', 'private_name': '_age'}

이제 새 클래스는 name과 age 모두에 대한 액세스를 로그 합니다:

>>> pete = Person('Peter P', 10)
INFO:root:Updating 'name' to 'Peter P'
INFO:root:Updating 'age' to 10
>>> kate = Person('Catherine C', 20)
INFO:root:Updating 'name' to 'Catherine C'
INFO:root:Updating 'age' to 20

두 개의 Person 인스턴스에는 개인 이름만 포함됩니다:

>>> vars(pete)
{'_name': 'Peter P', '_age': 10}
>>> vars(kate)
{'_name': 'Catherine C', '_age': 20}

마무리 생각

A descriptor is what we call any object that defines __get__(), __set__(), or __delete__().

Optionally, descriptors can have a __set_name__() method. This is only used in cases where a descriptor needs to know either the class where it was created or the name of class variable it was assigned to. (This method, if present, is called even if the class is not a descriptor.)

Descriptors get invoked by the dot operator during attribute lookup. If a descriptor is accessed indirectly with vars(some_class)[descriptor_name], the descriptor instance is returned without invoking it.

디스크립터는 클래스 변수로 사용될 때만 작동합니다. 인스턴스에 넣으면, 효과가 없습니다.

디스크립터의 주요 동기는 클래스 변수에 저장된 객체가 어트리뷰트 조회 중에 발생하는 일을 제어 할 수 있도록 하는 훅을 제공하는 것입니다.

전통적으로, 호출하는 클래스가 조회 중에 어떤 일이 일어날지 제어합니다. 디스크립터는 그 관계를 역전시키고 조회 중인 데이터가 발언권을 갖도록 합니다.

디스크립터는 언어 전체에서 사용됩니다. 함수가 연결된 메서드로 바뀌는 방법입니다. classmethod(), staticmethod(), property() 및 functools.cached_property()와 같은 일반적인 도구는 모두 디스크립터로 구현됩니다.

완전한 실용적인 예

이 예에서는, 찾기가 매우 어려운 것으로 악명 높은 데이터 손상 버그의 위치를 찾기 위한 실용적이고 강력한 도구를 만듭니다.

유효성 검사기 클래스

유효성 검사기는 관리되는 어트리뷰트 액세스를 위한 디스크립터입니다. 데이터를 저장하기 전에, 새 값이 다양한 형과 범위 제한을 충족하는지 확인합니다. 이러한 제한 사항이 충족되지 않으면, 데이터 손상을 방지하기 위해 원천에서 예외가 발생합니다.

This Validator class is both an abstract base class and a managed attribute descriptor:

from abc import ABC, abstractmethod

class Validator(ABC):

    def __set_name__(self, owner, name):
        self.private_name = '_' + name

    def __get__(self, obj, objtype=None):
        return getattr(obj, self.private_name)

    def __set__(self, obj, value):
        self.validate(value)
        setattr(obj, self.private_name, value)

    @abstractmethod
    def validate(self, value):
        pass

Custom validators need to inherit from Validator and must supply a validate() method to test various restrictions as needed.

사용자 정의 유효성 검사기

다음은 세 가지 실용적인 데이터 유효성 검사 유틸리티입니다:

OneOf verifies that a value is one of a restricted set of options.

Number verifies that a value is either an int or float. Optionally, it verifies that a value is between a given minimum or maximum.

String verifies that a value is a str. Optionally, it validates a given minimum or maximum length. It can validate a user-defined predicate [https://en.wikipedia.org/wiki/Predicate_(mathematical_logic)] as well.

class OneOf(Validator):

    def __init__(self, *options):
        self.options = set(options)

    def validate(self, value):
        if value not in self.options:
            raise ValueError(
                f'Expected {value!r} to be one of {self.options!r}'
            )

class Number(Validator):

    def __init__(self, minvalue=None, maxvalue=None):
        self.minvalue = minvalue
        self.maxvalue = maxvalue

    def validate(self, value):
        if not isinstance(value, (int, float)):
            raise TypeError(f'Expected {value!r} to be an int or float')
        if self.minvalue is not None and value < self.minvalue:
            raise ValueError(
                f'Expected {value!r} to be at least {self.minvalue!r}'
            )
        if self.maxvalue is not None and value > self.maxvalue:
            raise ValueError(
                f'Expected {value!r} to be no more than {self.maxvalue!r}'
            )

class String(Validator):

    def __init__(self, minsize=None, maxsize=None, predicate=None):
        self.minsize = minsize
        self.maxsize = maxsize
        self.predicate = predicate

    def validate(self, value):
        if not isinstance(value, str):
            raise TypeError(f'Expected {value!r} to be an str')
        if self.minsize is not None and len(value) < self.minsize:
            raise ValueError(
                f'Expected {value!r} to be no smaller than {self.minsize!r}'
            )
        if self.maxsize is not None and len(value) > self.maxsize:
            raise ValueError(
                f'Expected {value!r} to be no bigger than {self.maxsize!r}'
            )
        if self.predicate is not None and not self.predicate(value):
            raise ValueError(
                f'Expected {self.predicate} to be true for {value!r}'
            )

실용적인 응용

실제 클래스에서 데이터 유효성 검사기를 사용하는 방법은 다음과 같습니다:

class Component:

    name = String(minsize=3, maxsize=10, predicate=str.isupper)
    kind = OneOf('wood', 'metal', 'plastic')
    quantity = Number(minvalue=0)

    def __init__(self, name, kind, quantity):
        self.name = name
        self.kind = kind
        self.quantity = quantity

디스크립터는 잘못된 인스턴스가 만들어지는 것을 방지합니다:

>>> Component('Widget', 'metal', 5)      # Blocked: 'Widget' is not all uppercase
Traceback (most recent call last):
    ...
ValueError: Expected <method 'isupper' of 'str' objects> to be true for 'Widget'

>>> Component('WIDGET', 'metle', 5)      # Blocked: 'metle' is misspelled
Traceback (most recent call last):
    ...
ValueError: Expected 'metle' to be one of {'metal', 'plastic', 'wood'}

>>> Component('WIDGET', 'metal', -5)     # Blocked: -5 is negative
Traceback (most recent call last):
    ...
ValueError: Expected -5 to be at least 0

>>> Component('WIDGET', 'metal', 'V')    # Blocked: 'V' isn't a number
Traceback (most recent call last):
    ...
TypeError: Expected 'V' to be an int or float

>>> c = Component('WIDGET', 'metal', 5)  # Allowed:  The inputs are valid

기술적인 자습서

다음은 디스크립터의 작동 원리와 세부 사항에 대한 더 기술적인 자습서입니다.

요약

디스크립터를 정의하고, 프로토콜을 요약하며 디스크립터를 호출하는 방법을 보여줍니다. 객체 관계형 매핑(object relational mappings)이 작동하는 방식을 보여주는 예를 제공합니다.

디스크립터에 대한 학습은 더 큰 도구 집합에 대한 액세스를 제공할 뿐만 아니라, 파이썬의 작동 방식에 대한 심층적인 이해를 만듭니다.

정의와 소개

In general, a descriptor is an attribute value that has one of the methods in the descriptor protocol. Those methods are __get__(), __set__(), and __delete__(). If any of those methods are defined for an attribute, it is said to be a descriptor.

어트리뷰트 액세스의 기본 동작은 객체의 딕셔너리에서 어트리뷰트를 가져오거나(get) 설정하거나(set) 삭제하는(delete) 것입니다. 예를 들어, a.x는 a.__dict__['x']로 시작한 다음 type(a).__dict__['x']를 거쳐, type(a)의 메서드 결정 순서로 계속되는 조회 체인을 갖습니다. 조회된 값이 디스크립터 메서드 중 하나를 정의하는 객체이면, 파이썬은 기본 동작을 대체하고 대신 디스크립터 메서드를 호출 할 수 있습니다. 우선순위 체인에서 이것이 어디쯤 등장하는지는 어떤 디스크립터 메서드가 정의되었는지에 따라 다릅니다.

Descriptors are a powerful, general purpose protocol. They are the mechanism behind properties, methods, static methods, class methods, and super(). They are used throughout Python itself. Descriptors simplify the underlying C code and offer a flexible set of new tools for everyday Python programs.

디스크립터 프로토콜

descr.__get__(self, obj, type=None)

descr.__set__(self, obj, value)

descr.__delete__(self, obj)

이것이 전부입니다. 이러한 메서드 중 하나를 정의하십시오, 그러면 객체를 디스크립터로 간주하고 어트리뷰트로 조회될 때 기본 동작을 재정의할 수 있습니다.

If an object defines __set__() or __delete__(), it is considered a data descriptor. Descriptors that only define __get__() are called non-data descriptors (they are often used for methods but other uses are possible).

데이터와 비 데이터 디스크립터는 인스턴스 딕셔너리의 항목과 관련하여 재정의가 계산되는 방식이 다릅니다. 인스턴스 딕셔너리에 데이터 디스크립터와 이름이 같은 항목이 있으면, 데이터 디스크립터가 우선합니다. 인스턴스의 딕셔너리에 비 데이터 디스크립터와 이름이 같은 항목이 있으면, 딕셔너리 항목이 우선합니다.

To make a read-only data descriptor, define both __get__() and __set__() with the __set__() raising an AttributeError when called. Defining the __set__() method with an exception raising placeholder is enough to make it a data descriptor.

디스크립터 호출의 개요

디스크립터는 desc.__get__(obj)나 desc.__get__(None, cls)로 직접 호출 할 수 있습니다.

하지만 어트리뷰트 액세스 시 디스크립터가 자동으로 호출되는 것이 더 일반적입니다.

The expression obj.x looks up the attribute x in the chain of namespaces for obj. If the search finds a descriptor outside of the instance __dict__, its __get__() method is invoked according to the precedence rules listed below.

호출 세부 사항은 obj가 객체, 클래스 혹은 super의 인스턴스인지에 따라 다릅니다.

인스턴스에서 호출

Instance lookup scans through a chain of namespaces giving data descriptors the highest priority, followed by instance variables, then non-data descriptors, then class variables, and lastly __getattr__() if it is provided.

a.x에 대한 디스크립터가 발견되면, desc.__get__(a, type(a))로 호출됩니다.

점 조회의 로직은 object.__getattribute__()에 있습니다. 다음은 순수한 파이썬 등가물입니다:

def find_name_in_mro(cls, name, default):
    "Emulate _PyType_Lookup() in Objects/typeobject.c"
    for base in cls.__mro__:
        if name in vars(base):
            return vars(base)[name]
    return default

def object_getattribute(obj, name):
    "Emulate PyObject_GenericGetAttr() in Objects/object.c"
    null = object()
    objtype = type(obj)
    cls_var = find_name_in_mro(objtype, name, null)
    descr_get = getattr(type(cls_var), '__get__', null)
    if descr_get is not null:
        if (hasattr(type(cls_var), '__set__')
            or hasattr(type(cls_var), '__delete__')):
            return descr_get(cls_var, obj, objtype)     # data descriptor
    if hasattr(obj, '__dict__') and name in vars(obj):
        return vars(obj)[name]                          # instance variable
    if descr_get is not null:
        return descr_get(cls_var, obj, objtype)         # non-data descriptor
    if cls_var is not null:
        return cls_var                                  # class variable
    raise AttributeError(name)

Note, there is no __getattr__() hook in the __getattribute__() code. That is why calling __getattribute__() directly or with super().__getattribute__ will bypass __getattr__() entirely.

Instead, it is the dot operator and the getattr() function that are responsible for invoking __getattr__() whenever __getattribute__() raises an AttributeError. Their logic is encapsulated in a helper function:

def getattr_hook(obj, name):
    "Emulate slot_tp_getattr_hook() in Objects/typeobject.c"
    try:
        return obj.__getattribute__(name)
    except AttributeError:
        if not hasattr(type(obj), '__getattr__'):
            raise
    return type(obj).__getattr__(obj, name)             # __getattr__

클래스에서 호출

The logic for a dotted lookup such as A.x is in type.__getattribute__(). The steps are similar to those for object.__getattribute__() but the instance dictionary lookup is replaced by a search through the class’s method resolution order.

디스크립터가 발견되면, desc.__get__(None, A)로 호출됩니다.

The full C implementation can be found in type_getattro() and _PyType_Lookup() in Objects/typeobject.c [https://github.com/python/cpython/tree/main/Objects/typeobject.c].

super에서 호출

The logic for super’s dotted lookup is in the __getattribute__() method for object returned by super().

점 조회 super(A, obj).m은 obj.__class__.__mro__에서 A 바로 다음에 오는 베이스 클래스 B를 검색한 다음 B.__dict__['m'].__get__(obj, A)를 반환합니다. 디스크립터가 아니면, m이 변경되지 않은 상태로 반환됩니다.

The full C implementation can be found in super_getattro() in Objects/typeobject.c [https://github.com/python/cpython/tree/main/Objects/typeobject.c]. A pure Python equivalent can be found in Guido’s Tutorial [https://www.python.org/download/releases/2.2.3/descrintro/#cooperation].

호출 로직 요약

The mechanism for descriptors is embedded in the __getattribute__() methods for object, type, and super().

기억해야 할 중요한 사항은 다음과 같습니다:

Descriptors are invoked by the __getattribute__() method.

클래스는 object, type 또는 super()로부터 이 절차를 상속합니다.

Overriding __getattribute__() prevents automatic descriptor calls because all the descriptor logic is in that method.

object.__getattribute__() and type.__getattribute__() make different calls to __get__(). The first includes the instance and may include the class. The second puts in None for the instance and always includes the class.

데이터 디스크립터는 항상 인스턴스 딕셔너리를 대체합니다.

비 데이터 디스크립터는 인스턴스 딕셔너리로 대체될 수 있습니다.

자동 이름 알림

Sometimes it is desirable for a descriptor to know what class variable name it was assigned to. When a new class is created, the type metaclass scans the dictionary of the new class. If any of the entries are descriptors and if they define __set_name__(), that method is called with two arguments. The owner is the class where the descriptor is used, and the name is the class variable the descriptor was assigned to.

The implementation details are in type_new() and set_names() in Objects/typeobject.c [https://github.com/python/cpython/tree/main/Objects/typeobject.c].

Since the update logic is in type.__new__(), notifications only take place at the time of class creation. If descriptors are added to the class afterwards, __set_name__() will need to be called manually.

ORM 예제

The following code is a simplified skeleton showing how data descriptors could be used to implement an object relational mapping [https://en.wikipedia.org/wiki/Object%E2%80%93relational_mapping].

핵심 아이디어는 데이터가 외부 데이터베이스에 저장된다는 것입니다. 파이썬 인스턴스는 데이터베이스 테이블에 대한 키만 보유합니다. 디스크립터가 조회나 갱신을 처리합니다:

class Field:

    def __set_name__(self, owner, name):
        self.fetch = f'SELECT {name} FROM {owner.table} WHERE {owner.key}=?;'
        self.store = f'UPDATE {owner.table} SET {name}=? WHERE {owner.key}=?;'

    def __get__(self, obj, objtype=None):
        return conn.execute(self.fetch, [obj.key]).fetchone()[0]

    def __set__(self, obj, value):
        conn.execute(self.store, [value, obj.key])
        conn.commit()

We can use the Field class to define models [https://en.wikipedia.org/wiki/Database_model] that describe the schema for each table in a database:

class Movie:
    table = 'Movies'                    # Table name
    key = 'title'                       # Primary key
    director = Field()
    year = Field()

    def __init__(self, key):
        self.key = key

class Song:
    table = 'Music'
    key = 'title'
    artist = Field()
    year = Field()
    genre = Field()

    def __init__(self, key):
        self.key = key

모델을 사용하려면, 먼저 데이터베이스에 연결하십시오:

>>> import sqlite3
>>> conn = sqlite3.connect('entertainment.db')

대화 형 세션은 데이터베이스에서 데이터를 꺼내는 방법과 데이터를 갱신하는 방법을 보여줍니다:

>>> Movie('Star Wars').director
'George Lucas'
>>> jaws = Movie('Jaws')
>>> f'Released in {jaws.year} by {jaws.director}'
'Released in 1975 by Steven Spielberg'

>>> Song('Country Roads').artist
'John Denver'

>>> Movie('Star Wars').director = 'J.J. Abrams'
>>> Movie('Star Wars').director
'J.J. Abrams'

순수한 파이썬 등가물

디스트립터 프로토콜은 간단하고 흥미로운 가능성을 제공합니다. 몇 가지 유스 케이스는 아주 흔해서 내장 도구에 미리 패키징되었습니다. 프로퍼티, 연결된 메서드, 정적 메서드, 클래스 메서드 및 __slots__는 모두 디스크립터 프로토콜을 기반으로 합니다.

프로퍼티

property() 호출은 어트리뷰트에 액세스할 때 함수 호출을 트리거 하는 데이터 디스크립터를 작성하는 간결한 방법입니다. 서명은 다음과 같습니다:

property(fget=None, fset=None, fdel=None, doc=None) -> property

설명(doc)은 관리되는 어트리뷰트 x를 정의하는 일반적인 사용법을 보여줍니다:

class C:
    def getx(self): return self.__x
    def setx(self, value): self.__x = value
    def delx(self): del self.__x
    x = property(getx, setx, delx, "I'm the 'x' property.")

To see how property() is implemented in terms of the descriptor protocol, here is a pure Python equivalent that implements most of the core functionality:

class Property:
    "Emulate PyProperty_Type() in Objects/descrobject.c"

    def __init__(self, fget=None, fset=None, fdel=None, doc=None):
        self.fget = fget
        self.fset = fset
        self.fdel = fdel
        if doc is None and fget is not None:
            doc = fget.__doc__
        self.__doc__ = doc

    def __set_name__(self, owner, name):
        self.__name__ = name

    def __get__(self, obj, objtype=None):
        if obj is None:
            return self
        if self.fget is None:
            raise AttributeError
        return self.fget(obj)

    def __set__(self, obj, value):
        if self.fset is None:
            raise AttributeError
        self.fset(obj, value)

    def __delete__(self, obj):
        if self.fdel is None:
            raise AttributeError
        self.fdel(obj)

    def getter(self, fget):
        return type(self)(fget, self.fset, self.fdel, self.__doc__)

    def setter(self, fset):
        return type(self)(self.fget, fset, self.fdel, self.__doc__)

    def deleter(self, fdel):
        return type(self)(self.fget, self.fset, fdel, self.__doc__)

property() 내장은 사용자 인터페이스가 어트리뷰트 액세스를 허가한 후 후속 변경이 메서드의 개입을 요구할 때 도움을 줍니다.

예를 들어, 스프레드시트 클래스는 Cell('b10').value를 통해 셀 값에 대한 액세스를 허가할 수 있습니다. 프로그램에 대한 후속 개선은 액세스할 때마다 셀이 재계산될 것을 요구합니다; 하지만, 프로그래머는 어트리뷰트에 직접 액세스하는 기존 클라이언트 코드에 영향을 미치고 싶지 않습니다. 해결책은 프로퍼티 데이터 디스크립터로 value 어트리뷰트에 대한 액세스를 감싸는 것입니다:

class Cell:
    ...

    @property
    def value(self):
        "Recalculate the cell before returning value"
        self.recalc()
        return self._value

Either the built-in property() or our Property() equivalent would work in this example.

함수와 메서드

파이썬의 객체 지향 기능은 함수 기반 환경을 기반으로 합니다. 비 데이터 디스크립터를 사용하면, 두 개가 매끄럽게 병합됩니다.

클래스 딕셔너리에 저장된 함수는 호출될 때 메서드로 바뀝니다. 객체 인스턴스가 다른 인자들 앞에 추가된다는 점에서만 메서드가 일반 함수와 다릅니다. 관례에 따라, 이 인스턴스는 self라고 하지만 this나 다른 어떤 변수 이름도 될 수 있습니다.

대략 다음과 동등한 types.MethodType을 사용하여 메서드를 수동으로 만들 수 있습니다:

class MethodType:
    "Emulate PyMethod_Type in Objects/classobject.c"

    def __init__(self, func, obj):
        self.__func__ = func
        self.__self__ = obj

    def __call__(self, *args, **kwargs):
        func = self.__func__
        obj = self.__self__
        return func(obj, *args, **kwargs)

    def __getattribute__(self, name):
        "Emulate method_getset() in Objects/classobject.c"
        if name == '__doc__':
            return self.__func__.__doc__
        return object.__getattribute__(self, name)

    def __getattr__(self, name):
        "Emulate method_getattro() in Objects/classobject.c"
        return getattr(self.__func__, name)

    def __get__(self, obj, objtype=None):
        "Emulate method_descr_get() in Objects/classobject.c"
        return self

To support automatic creation of methods, functions include the __get__() method for binding methods during attribute access. This means that functions are non-data descriptors that return bound methods during dotted lookup from an instance. Here’s how it works:

class Function:
    ...

    def __get__(self, obj, objtype=None):
        "Simulate func_descr_get() in Objects/funcobject.c"
        if obj is None:
            return self
        return MethodType(self, obj)

인터프리터에서 다음 클래스를 실행하면 실제로 함수 디스크립터가 작동하는 방식을 보여줍니다:

class D:
    def f(self):
         return self

class D2:
    pass

함수에는 내부 검사를 지원하는 정규화된 이름 어트리뷰트가 있습니다:

>>> D.f.__qualname__
'D.f'

Accessing the function through the class dictionary does not invoke __get__(). Instead, it just returns the underlying function object:

>>> D.__dict__['f']
<function D.f at 0x00C45070>

Dotted access from a class calls __get__() which just returns the underlying function unchanged:

>>> D.f
<function D.f at 0x00C45070>

The interesting behavior occurs during dotted access from an instance. The dotted lookup calls __get__() which returns a bound method object:

>>> d = D()
>>> d.f
<bound method D.f of <__main__.D object at 0x00B18C90>>

내부적으로, 연결된 메서드는 하부 함수와 연결된 인스턴스를 저장합니다.

>>> d.f.__func__
<function D.f at 0x00C45070>

>>> d.f.__self__
<__main__.D object at 0x00B18C90>

일반 메서드에서 self가 어디에서 오는지 또는 클래스 메서드에서 cls가 어디에서 오는지 궁금한 적이 있다면, 바로 이겁니다!

메서드의 종류

비 데이터 디스크립터는 함수에 메서드를 바인딩하는 일반적인 패턴을 변형하는 간단한 메커니즘을 제공합니다.

To recap, functions have a __get__() method so that they can be converted to a method when accessed as attributes. The non-data descriptor transforms an obj.f(*args) call into f(obj, *args). Calling cls.f(*args) becomes f(*args).

이 표는 연결과 가장 유용한 두 가지 변형을 요약합니다:

변환

객체에서 호출

클래스에서 호출

함수

f(obj, *args)

f(*args)

staticmethod

f(*args)

f(*args)

classmethod

f(type(obj), *args)

f(cls, *args)

정적 메서드

정적 메서드는 변경 없이 하부 함수를 반환합니다. c.f나 C.f 호출은 object.__getattribute__(c, "f")나 object.__getattribute__(C, "f")를 직접 조회하는 것과 동등합니다. 결과적으로, 함수는 객체나 클래스에서 동일하게 액세스 할 수 있습니다.

정적 메서드에 적합한 후보는 self 변수를 참조하지 않는 메서드입니다.

For instance, a statistics package may include a container class for experimental data. The class provides normal methods for computing the average, mean, median, and other descriptive statistics that depend on the data. However, there may be useful functions which are conceptually related but do not depend on the data. For instance, erf(x) is handy conversion routine that comes up in statistical work but does not directly depend on a particular dataset. It can be called either from an object or the class: s.erf(1.5) --> 0.9332 or Sample.erf(1.5) --> 0.9332.

정적 메서드는 변경 없이 하부 함수를 반환하므로, 예제 호출은 흥미롭지 않습니다:

class E:
    @staticmethod
    def f(x):
        return x * 10

>>> E.f(3)
30
>>> E().f(3)
30

비 데이터 디스크립터 프로토콜을 사용하면, 순수 파이썬 버전의 staticmethod()는 다음과 같습니다:

import functools

class StaticMethod:
    "Emulate PyStaticMethod_Type() in Objects/funcobject.c"

    def __init__(self, f):
        self.f = f
        functools.update_wrapper(self, f)

    def __get__(self, obj, objtype=None):
        return self.f

    def __call__(self, *args, **kwds):
        return self.f(*args, **kwds)

    @property
    def __annotations__(self):
        return self.f.__annotations__

The functools.update_wrapper() call adds a __wrapped__ attribute that refers to the underlying function. Also it carries forward the attributes necessary to make the wrapper look like the wrapped function, including __name__, __qualname__, and __doc__.

클래스 메서드

정적 메서드와 달리, 클래스 메서드는 함수를 호출하기 전에 클래스 참조를 인자 목록 앞에 추가합니다. 이 형식은 호출자가 객체나 클래스일 때 같습니다:

class F:
    @classmethod
    def f(cls, x):
        return cls.__name__, x

>>> F.f(3)
('F', 3)
>>> F().f(3)
('F', 3)

이 동작은 함수가 클래스 참조 만 필요하고 특정 인스턴스에 저장된 데이터에 의존하지 않을 때 유용합니다. 클래스 메서드의 한 가지 용도는 대체 클래스 생성자를 만드는 것입니다. 예를 들어, 클래스 메서드 dict.fromkeys()는 키 리스트에서 새 딕셔너리를 만듭니다. 순수한 파이썬 동등 물은 다음과 같습니다:

class Dict(dict):
    @classmethod
    def fromkeys(cls, iterable, value=None):
        "Emulate dict_fromkeys() in Objects/dictobject.c"
        d = cls()
        for key in iterable:
            d[key] = value
        return d

이제 고유 키의 새로운 딕셔너리를 다음과 같이 구성 할 수 있습니다:

>>> d = Dict.fromkeys('abracadabra')
>>> type(d) is Dict
True
>>> d
{'a': None, 'b': None, 'r': None, 'c': None, 'd': None}

비 데이터 디스크립터 프로토콜을 사용하면, 순수 파이썬 버전의 classmethod()는 다음과 같습니다:

import functools

class ClassMethod:
    "Emulate PyClassMethod_Type() in Objects/funcobject.c"

    def __init__(self, f):
        self.f = f
        functools.update_wrapper(self, f)

    def __get__(self, obj, cls=None):
        if cls is None:
            cls = type(obj)
        return MethodType(self.f, cls)

The functools.update_wrapper() call in ClassMethod adds a __wrapped__ attribute that refers to the underlying function. Also it carries forward the attributes necessary to make the wrapper look like the wrapped function: __name__, __qualname__, __doc__, and __annotations__.

멤버 객체와 __slots__

클래스가 __slots__를 정의하면, 인스턴스 딕셔너리를 슬롯값의 고정 길이 배열로 바꿉니다. 사용자 관점에서 여러 가지 효과가 있습니다:

1 - 철자가 잘못된 어트리뷰트 대입으로 인한 버그를 즉시 감지합니다. __slots__에 지정된 어트리뷰트 이름 만 허용됩니다:

class Vehicle:
    __slots__ = ('id_number', 'make', 'model')

>>> auto = Vehicle()
>>> auto.id_nubmer = 'VYE483814LQEX'
Traceback (most recent call last):
    ...
AttributeError: 'Vehicle' object has no attribute 'id_nubmer'

2 - 디스크립터가 __slots__에 저장된 개인 어트리뷰트에 대한 액세스를 관리하는 불변 객체를 만드는 데 도움이 됩니다:

class Immutable:

    __slots__ = ('_dept', '_name')          # Replace the instance dictionary

    def __init__(self, dept, name):
        self._dept = dept                   # Store to private attribute
        self._name = name                   # Store to private attribute

    @property                               # Read-only descriptor
    def dept(self):
        return self._dept

    @property
    def name(self):                         # Read-only descriptor
        return self._name

>>> mark = Immutable('Botany', 'Mark Watney')
>>> mark.dept
'Botany'
>>> mark.dept = 'Space Pirate'
Traceback (most recent call last):
    ...
AttributeError: property 'dept' of 'Immutable' object has no setter
>>> mark.location = 'Mars'
Traceback (most recent call last):
    ...
AttributeError: 'Immutable' object has no attribute 'location'

3 - 메모리를 절약합니다. 64비트 리눅스 빌드에서 두 개의 어트리뷰트가 있는 인스턴스는 __slots__가 있으면 48바이트, 없으면 152바이트를 사용합니다. 이 플라이웨이트(flyweight) 디자인 패턴 [https://en.wikipedia.org/wiki/Flyweight_pattern]은 많은 수의 인스턴스가 만들어질 때만 중요합니다.

4. Improves speed. Reading instance variables is 35% faster with __slots__ (as measured with Python 3.10 on an Apple M1 processor).

5. Blocks tools like functools.cached_property() which require an instance dictionary to function correctly:

from functools import cached_property

class CP:
    __slots__ = ()                          # Eliminates the instance dict

    @cached_property                        # Requires an instance dict
    def pi(self):
        return 4 * sum((-1.0)**n / (2.0*n + 1.0)
                       for n in reversed(range(100_000)))

>>> CP().pi
Traceback (most recent call last):
  ...
TypeError: No '__dict__' attribute on 'CP' instance to cache 'pi' property.

__slots__의 정확한 순수 파이썬 드롭인 버전을 만드는 것은 불가능합니다. C 구조체에 직접 액세스하고 객체 메모리 할당을 제어해야 하기 때문입니다. 그러나, 슬롯에 대한 실제 C 구조체가 개인 _slotvalues 리스트에 의해 모사되는 가장 충실한 시뮬레이션을 구축 할 수 있습니다. 해당 개인 구조체에 대한 읽기와 쓰기는 멤버 디스크립터에 의해 관리됩니다:

null = object()

class Member:

    def __init__(self, name, clsname, offset):
        'Emulate PyMemberDef in Include/structmember.h'
        # Also see descr_new() in Objects/descrobject.c
        self.name = name
        self.clsname = clsname
        self.offset = offset

    def __get__(self, obj, objtype=None):
        'Emulate member_get() in Objects/descrobject.c'
        # Also see PyMember_GetOne() in Python/structmember.c
        if obj is None:
            return self
        value = obj._slotvalues[self.offset]
        if value is null:
            raise AttributeError(self.name)
        return value

    def __set__(self, obj, value):
        'Emulate member_set() in Objects/descrobject.c'
        obj._slotvalues[self.offset] = value

    def __delete__(self, obj):
        'Emulate member_delete() in Objects/descrobject.c'
        value = obj._slotvalues[self.offset]
        if value is null:
            raise AttributeError(self.name)
        obj._slotvalues[self.offset] = null

    def __repr__(self):
        'Emulate member_repr() in Objects/descrobject.c'
        return f'<Member {self.name!r} of {self.clsname!r}>'

The type.__new__() method takes care of adding member objects to class variables:

class Type(type):
    'Simulate how the type metaclass adds member objects for slots'

    def __new__(mcls, clsname, bases, mapping, **kwargs):
        'Emulate type_new() in Objects/typeobject.c'
        # type_new() calls PyTypeReady() which calls add_methods()
        slot_names = mapping.get('slot_names', [])
        for offset, name in enumerate(slot_names):
            mapping[name] = Member(name, clsname, offset)
        return type.__new__(mcls, clsname, bases, mapping, **kwargs)

object.__new__() 메서드는 인스턴스 딕셔너리 대신 슬롯이 있는 인스턴스를 만드는 것을 관장합니다. 다음은 순수 파이썬의 대략적인 시뮬레이션입니다:

class Object:
    'Simulate how object.__new__() allocates memory for __slots__'

    def __new__(cls, *args, **kwargs):
        'Emulate object_new() in Objects/typeobject.c'
        inst = super().__new__(cls)
        if hasattr(cls, 'slot_names'):
            empty_slots = [null] * len(cls.slot_names)
            object.__setattr__(inst, '_slotvalues', empty_slots)
        return inst

    def __setattr__(self, name, value):
        'Emulate _PyObject_GenericSetAttrWithDict() Objects/object.c'
        cls = type(self)
        if hasattr(cls, 'slot_names') and name not in cls.slot_names:
            raise AttributeError(
                f'{cls.__name__!r} object has no attribute {name!r}'
            )
        super().__setattr__(name, value)

    def __delattr__(self, name):
        'Emulate _PyObject_GenericSetAttrWithDict() Objects/object.c'
        cls = type(self)
        if hasattr(cls, 'slot_names') and name not in cls.slot_names:
            raise AttributeError(
                f'{cls.__name__!r} object has no attribute {name!r}'
            )
        super().__delattr__(name)

To use the simulation in a real class, just inherit from Object and set the metaclass to Type:

class H(Object, metaclass=Type):
    'Instance variables stored in slots'

    slot_names = ['x', 'y']

    def __init__(self, x, y):
        self.x = x
        self.y = y

이 시점에서, 메타 클래스는 x 와 y에 대한 멤버 객체를 로드했습니다:

>>> from pprint import pp
>>> pp(dict(vars(H)))
{'__module__': '__main__',
 '__doc__': 'Instance variables stored in slots',
 'slot_names': ['x', 'y'],
 '__init__': <function H.__init__ at 0x7fb5d302f9d0>,
 'x': <Member 'x' of 'H'>,
 'y': <Member 'y' of 'H'>}

인스턴스가 만들어질 때, 어트리뷰트가 저장되는 slot_values 리스트를 갖습니다:

>>> h = H(10, 20)
>>> vars(h)
{'_slotvalues': [10, 20]}
>>> h.x = 55
>>> vars(h)
{'_slotvalues': [55, 20]}

철자가 틀리거나 지정되지 않은 어트리뷰트는 예외를 발생시킵니다:

>>> h.xz
Traceback (most recent call last):
    ...
AttributeError: 'H' object has no attribute 'xz'

Debugging C API extensions and CPython Internals with GDB

This document explains how the Python GDB extension, python-gdb.py, can be used with the GDB debugger to debug CPython extensions and the CPython interpreter itself.

When debugging low-level problems such as crashes or deadlocks, a low-level debugger, such as GDB, is useful to diagnose and correct the issue. By default, GDB (or any of its front-ends) doesn’t support high-level information specific to the CPython interpreter.

The python-gdb.py extension adds CPython interpreter information to GDB. The extension helps introspect the stack of currently executing Python functions. Given a Python object represented by a PyObject* pointer, the extension surfaces the type and value of the object.

Developers who are working on CPython extensions or tinkering with parts of CPython that are written in C can use this document to learn how to use the python-gdb.py extension with GDB.

참고

This document assumes that you are familiar with the basics of GDB and the CPython C API. It consolidates guidance from the devguide [https://devguide.python.org] and the Python wiki [https://wiki.python.org/moin/DebuggingWithGdb].

Prerequisites

You need to have:

GDB 7 or later. (For earlier versions of GDB, see Misc/gdbinit in the sources of Python 3.11 or earlier.)

GDB-compatible debugging information for Python and any extension you are debugging.

The python-gdb.py extension.

The extension is built with Python, but might be distributed separately or not at all. Below, we include tips for a few common systems as examples. Note that even if the instructions match your system, they might be outdated.

Setup with Python built from source

When you build CPython from source, debugging information should be available, and the build should add a python-gdb.py file to the root directory of your repository.

To activate support, you must add the directory containing python-gdb.py to GDB’s “auto-load-safe-path”. If you haven’t done this, recent versions of GDB will print out a warning with instructions on how to do this.

참고

If you do not see instructions for your version of GDB, put this in your configuration file (~/.gdbinit or ~/.config/gdb/gdbinit):

add-auto-load-safe-path /path/to/cpython

You can also add multiple paths, separated by :.

Setup for Python from a Linux distro

Most Linux systems provide debug information for the system Python in a package called python-debuginfo, python-dbg or similar. For example:

Fedora:

sudo dnf install gdb
sudo dnf debuginfo-install python3

Ubuntu:

sudo apt install gdb python3-dbg

On several recent Linux systems, GDB can download debugging symbols automatically using debuginfod. However, this will not install the python-gdb.py extension; you generally do need to install the debug info package separately.

Using the Debug build and Development mode

For easier debugging, you might want to:

Use a debug build of Python. (When building from source, use configure --with-pydebug. On Linux distros, install and run a package like python-debug or python-dbg, if available.)

Use the runtime development mode (-X dev).

Both enable extra assertions and disable some optimizations. Sometimes this hides the bug you are trying to find, but in most cases they make the process easier.

Using the python-gdb extension

When the extension is loaded, it provides two main features: pretty printers for Python values, and additional commands.

Pretty-printers

This is what a GDB backtrace looks like (truncated) when this extension is enabled:

#0  0x000000000041a6b1 in PyObject_Malloc (nbytes=Cannot access memory at address 0x7fffff7fefe8
) at Objects/obmalloc.c:748
#1  0x000000000041b7c0 in _PyObject_DebugMallocApi (id=111 'o', nbytes=24) at Objects/obmalloc.c:1445
#2  0x000000000041b717 in _PyObject_DebugMalloc (nbytes=24) at Objects/obmalloc.c:1412
#3  0x000000000044060a in _PyUnicode_New (length=11) at Objects/unicodeobject.c:346
#4  0x00000000004466aa in PyUnicodeUCS2_DecodeUTF8Stateful (s=0x5c2b8d "__lltrace__", size=11, errors=0x0, consumed=
    0x0) at Objects/unicodeobject.c:2531
#5  0x0000000000446647 in PyUnicodeUCS2_DecodeUTF8 (s=0x5c2b8d "__lltrace__", size=11, errors=0x0)
    at Objects/unicodeobject.c:2495
#6  0x0000000000440d1b in PyUnicodeUCS2_FromStringAndSize (u=0x5c2b8d "__lltrace__", size=11)
    at Objects/unicodeobject.c:551
#7  0x0000000000440d94 in PyUnicodeUCS2_FromString (u=0x5c2b8d "__lltrace__") at Objects/unicodeobject.c:569
#8  0x0000000000584abd in PyDict_GetItemString (v=
    {'Yuck': <type at remote 0xad4730>, '__builtins__': <module at remote 0x7ffff7fd5ee8>, '__file__': 'Lib/test/crashers/nasty_eq_vs_dict.py', '__package__': None, 'y': <Yuck(i=0) at remote 0xaacd80>, 'dict': {0: 0, 1: 1, 2: 2, 3: 3}, '__cached__': None, '__name__': '__main__', 'z': <Yuck(i=0) at remote 0xaace60>, '__doc__': None}, key=
    0x5c2b8d "__lltrace__") at Objects/dictobject.c:2171

Notice how the dictionary argument to PyDict_GetItemString is displayed as its repr(), rather than an opaque PyObject * pointer.

The extension works by supplying a custom printing routine for values of type PyObject *. If you need to access lower-level details of an object, then cast the value to a pointer of the appropriate type. For example:

(gdb) p globals
$1 = {'__builtins__': <module at remote 0x7ffff7fb1868>, '__name__':
'__main__', 'ctypes': <module at remote 0x7ffff7f14360>, '__doc__': None,
'__package__': None}

(gdb) p *(PyDictObject*)globals
$2 = {ob_refcnt = 3, ob_type = 0x3dbdf85820, ma_fill = 5, ma_used = 5,
ma_mask = 7, ma_table = 0x63d0f8, ma_lookup = 0x3dbdc7ea70
<lookdict_string>, ma_smalltable = {{me_hash = 7065186196740147912,
me_key = '__builtins__', me_value = <module at remote 0x7ffff7fb1868>},
{me_hash = -368181376027291943, me_key = '__name__',
me_value ='__main__'}, {me_hash = 0, me_key = 0x0, me_value = 0x0},
{me_hash = 0, me_key = 0x0, me_value = 0x0},
{me_hash = -9177857982131165996, me_key = 'ctypes',
me_value = <module at remote 0x7ffff7f14360>},
{me_hash = -8518757509529533123, me_key = '__doc__', me_value = None},
{me_hash = 0, me_key = 0x0, me_value = 0x0}, {
  me_hash = 6614918939584953775, me_key = '__package__', me_value = None}}}

Note that the pretty-printers do not actually call repr(). For basic types, they try to match its result closely.

An area that can be confusing is that the custom printer for some types look a lot like GDB’s built-in printer for standard types. For example, the pretty-printer for a Python int (PyLongObject*) gives a representation that is not distinguishable from one of a regular machine-level integer:

(gdb) p some_machine_integer
$3 = 42

(gdb) p some_python_integer
$4 = 42

The internal structure can be revealed with a cast to PyLongObject*:

(gdb) p (PyLongObject)some_python_integer $5 = {ob_base = {ob_base = {ob_refcnt = 8, ob_type = 0x3dad39f5e0}, ob_size = 1}, ob_digit = {42}}

A similar confusion can arise with the str type, where the output looks a lot like gdb’s built-in printer for char *:

(gdb) p ptr_to_python_str
$6 = '__builtins__'

The pretty-printer for str instances defaults to using single-quotes (as does Python’s repr for strings) whereas the standard printer for char * values uses double-quotes and contains a hexadecimal address:

(gdb) p ptr_to_char_star
$7 = 0x6d72c0 "hello world"

Again, the implementation details can be revealed with a cast to PyUnicodeObject*:

(gdb) p *(PyUnicodeObject*)$6
$8 = {ob_base = {ob_refcnt = 33, ob_type = 0x3dad3a95a0}, length = 12,
str = 0x7ffff2128500, hash = 7065186196740147912, state = 1, defenc = 0x0}

py-list

The extension adds a py-list command, which lists the Python source code (if any) for the current frame in the selected thread. The current line is marked with a “>”:

(gdb) py-list
 901        if options.profile:
 902            options.profile = False
 903            profile_me()
 904            return
 905
>906        u = UI()
 907        if not u.quit:
 908            try:
 909                gtk.main()
 910            except KeyboardInterrupt:
 911                # properly quit on a keyboard interrupt...

Use py-list START to list at a different line number within the Python source, and py-list START,END to list a specific range of lines within the Python source.

py-up and py-down

The py-up and py-down commands are analogous to GDB’s regular up and down commands, but try to move at the level of CPython frames, rather than C frames.

GDB is not always able to read the relevant frame information, depending on the optimization level with which CPython was compiled. Internally, the commands look for C frames that are executing the default frame evaluation function (that is, the core bytecode interpreter loop within CPython) and look up the value of the related PyFrameObject *.

They emit the frame number (at the C level) within the thread.

For example:

(gdb) py-up
#37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/
gnome_sudoku/main.py, line 906, in start_game ()
    u = UI()
(gdb) py-up
#40 Frame 0x948e82c, for file /usr/lib/python2.6/site-packages/
gnome_sudoku/gnome_sudoku.py, line 22, in start_game(main=<module at remote 0xb771b7f4>)
    main.start_game()
(gdb) py-up
Unable to find an older python frame

so we’re at the top of the Python stack.

The frame numbers correspond to those displayed by GDB’s standard backtrace command. The command skips C frames which are not executing Python code.

Going back down:

(gdb) py-down
#37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/gnome_sudoku/main.py, line 906, in start_game ()
    u = UI()
(gdb) py-down
#34 (unable to read python frame information)
(gdb) py-down
#23 (unable to read python frame information)
(gdb) py-down
#19 (unable to read python frame information)
(gdb) py-down
#14 Frame 0x99262ac, for file /usr/lib/python2.6/site-packages/gnome_sudoku/game_selector.py, line 201, in run_swallowed_dialog (self=<NewOrSavedGameSelector(new_game_model=<gtk.ListStore at remote 0x98fab44>, puzzle=None, saved_games=[{'gsd.auto_fills': 0, 'tracking': {}, 'trackers': {}, 'notes': [], 'saved_at': 1270084485, 'game': '7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 0 0 0 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5\n7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 1 8 3 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5', 'gsd.impossible_hints': 0, 'timer.__absolute_start_time__': <float at remote 0x984b474>, 'gsd.hints': 0, 'timer.active_time': <float at remote 0x984b494>, 'timer.total_time': <float at remote 0x984b464>}], dialog=<gtk.Dialog at remote 0x98faaa4>, saved_game_model=<gtk.ListStore at remote 0x98fad24>, sudoku_maker=<SudokuMaker(terminated=False, played=[], batch_siz...(truncated)
            swallower.run_dialog(self.dialog)
(gdb) py-down
#11 Frame 0x9aead74, for file /usr/lib/python2.6/site-packages/gnome_sudoku/dialog_swallower.py, line 48, in run_dialog (self=<SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>, main_page=0) at remote 0x98fa6e4>, d=<gtk.Dialog at remote 0x98faaa4>)
            gtk.main()
(gdb) py-down
#8 (unable to read python frame information)
(gdb) py-down
Unable to find a newer python frame

and we’re at the bottom of the Python stack.

Note that in Python 3.12 and newer, the same C stack frame can be used for multiple Python stack frames. This means that py-up and py-down may move multiple Python frames at once. For example:

(gdb) py-up
#6 Frame 0x7ffff7fb62b0, for file /tmp/rec.py, line 5, in recursive_function (n=0)
   time.sleep(5)
#6 Frame 0x7ffff7fb6240, for file /tmp/rec.py, line 7, in recursive_function (n=1)
   recursive_function(n-1)
#6 Frame 0x7ffff7fb61d0, for file /tmp/rec.py, line 7, in recursive_function (n=2)
   recursive_function(n-1)
#6 Frame 0x7ffff7fb6160, for file /tmp/rec.py, line 7, in recursive_function (n=3)
   recursive_function(n-1)
#6 Frame 0x7ffff7fb60f0, for file /tmp/rec.py, line 7, in recursive_function (n=4)
   recursive_function(n-1)
#6 Frame 0x7ffff7fb6080, for file /tmp/rec.py, line 7, in recursive_function (n=5)
   recursive_function(n-1)
#6 Frame 0x7ffff7fb6020, for file /tmp/rec.py, line 9, in <module> ()
   recursive_function(5)
(gdb) py-up
Unable to find an older python frame

py-bt

The py-bt command attempts to display a Python-level backtrace of the current thread.

For example:

(gdb) py-bt
#8 (unable to read python frame information)
#11 Frame 0x9aead74, for file /usr/lib/python2.6/site-packages/gnome_sudoku/dialog_swallower.py, line 48, in run_dialog (self=<SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>, main_page=0) at remote 0x98fa6e4>, d=<gtk.Dialog at remote 0x98faaa4>)
            gtk.main()
#14 Frame 0x99262ac, for file /usr/lib/python2.6/site-packages/gnome_sudoku/game_selector.py, line 201, in run_swallowed_dialog (self=<NewOrSavedGameSelector(new_game_model=<gtk.ListStore at remote 0x98fab44>, puzzle=None, saved_games=[{'gsd.auto_fills': 0, 'tracking': {}, 'trackers': {}, 'notes': [], 'saved_at': 1270084485, 'game': '7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 0 0 0 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5\n7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 1 8 3 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5', 'gsd.impossible_hints': 0, 'timer.__absolute_start_time__': <float at remote 0x984b474>, 'gsd.hints': 0, 'timer.active_time': <float at remote 0x984b494>, 'timer.total_time': <float at remote 0x984b464>}], dialog=<gtk.Dialog at remote 0x98faaa4>, saved_game_model=<gtk.ListStore at remote 0x98fad24>, sudoku_maker=<SudokuMaker(terminated=False, played=[], batch_siz...(truncated)
            swallower.run_dialog(self.dialog)
#19 (unable to read python frame information)
#23 (unable to read python frame information)
#34 (unable to read python frame information)
#37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/gnome_sudoku/main.py, line 906, in start_game ()
    u = UI()
#40 Frame 0x948e82c, for file /usr/lib/python2.6/site-packages/gnome_sudoku/gnome_sudoku.py, line 22, in start_game (main=<module at remote 0xb771b7f4>)
    main.start_game()

The frame numbers correspond to those displayed by GDB’s standard backtrace command.

py-print

The py-print command looks up a Python name and tries to print it. It looks in locals within the current thread, then globals, then finally builtins:

(gdb) py-print self
local 'self' = <SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>,
main_page=0) at remote 0x98fa6e4>
(gdb) py-print __name__
global '__name__' = 'gnome_sudoku.dialog_swallower'
(gdb) py-print len
builtin 'len' = <built-in function len>
(gdb) py-print scarlet_pimpernel
'scarlet_pimpernel' not found

If the current C frame corresponds to multiple Python frames, py-print only considers the first one.

py-locals

The py-locals command looks up all Python locals within the current Python frame in the selected thread, and prints their representations:

(gdb) py-locals
self = <SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>,
main_page=0) at remote 0x98fa6e4>
d = <gtk.Dialog at remote 0x98faaa4>

If the current C frame corresponds to multiple Python frames, locals from all of them will be shown:

(gdb) py-locals
Locals for recursive_function
n = 0
Locals for recursive_function
n = 1
Locals for recursive_function
n = 2
Locals for recursive_function
n = 3
Locals for recursive_function
n = 4
Locals for recursive_function
n = 5
Locals for <module>

Use with GDB commands

The extension commands complement GDB’s built-in commands. For example, you can use a frame numbers shown by py-bt with the frame command to go a specific frame within the selected thread, like this:

(gdb) py-bt
(output snipped)
#68 Frame 0xaa4560, for file Lib/test/regrtest.py, line 1548, in <module> ()
        main()
(gdb) frame 68
#68 0x00000000004cd1e6 in PyEval_EvalFrameEx (f=Frame 0xaa4560, for file Lib/test/regrtest.py, line 1548, in <module> (), throwflag=0) at Python/ceval.c:2665
2665                            x = call_function(&sp, oparg);
(gdb) py-list
1543        # Run the tests in a context manager that temporary changes the CWD to a
1544        # temporary and writable directory. If it's not possible to create or
1545        # change the CWD, the original CWD will be used. The original CWD is
1546        # available from test_support.SAVEDCWD.
1547        with test_support.temp_cwd(TESTCWD, quiet=True):
>1548            main()

The info threads command will give you a list of the threads within the process, and you can use the thread command to select a different one:

(gdb) info threads
  105 Thread 0x7fffefa18710 (LWP 10260)  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:86
  104 Thread 0x7fffdf5fe710 (LWP 10259)  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:86
* 1 Thread 0x7ffff7fe2700 (LWP 10145)  0x00000038e46d73e3 in select () at ../sysdeps/unix/syscall-template.S:82

You can use thread apply all COMMAND or (t a a COMMAND for short) to run a command on all threads. With py-bt, this lets you see what every thread is doing at the Python level:

(gdb) t a a py-bt

Thread 105 (Thread 0x7fffefa18710 (LWP 10260)):
#5 Frame 0x7fffd00019d0, for file /home/david/coding/python-svn/Lib/threading.py, line 155, in _acquire_restore (self=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, count_owner=(1, 140737213728528), count=1, owner=140737213728528)
        self.__block.acquire()
#8 Frame 0x7fffac001640, for file /home/david/coding/python-svn/Lib/threading.py, line 269, in wait (self=<_Condition(_Condition__lock=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, acquire=<instancemethod at remote 0xd80260>, _is_owned=<instancemethod at remote 0xd80160>, _release_save=<instancemethod at remote 0xd803e0>, release=<instancemethod at remote 0xd802e0>, _acquire_restore=<instancemethod at remote 0xd7ee60>, _Verbose__verbose=False, _Condition__waiters=[]) at remote 0xd7fd10>, timeout=None, waiter=<thread.lock at remote 0x858a90>, saved_state=(1, 140737213728528))
            self._acquire_restore(saved_state)
#12 Frame 0x7fffb8001a10, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 348, in f ()
            cond.wait()
#16 Frame 0x7fffb8001c40, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 37, in task (tid=140737213728528)
                f()

Thread 104 (Thread 0x7fffdf5fe710 (LWP 10259)):
#5 Frame 0x7fffe4001580, for file /home/david/coding/python-svn/Lib/threading.py, line 155, in _acquire_restore (self=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, count_owner=(1, 140736940992272), count=1, owner=140736940992272)
        self.__block.acquire()
#8 Frame 0x7fffc8002090, for file /home/david/coding/python-svn/Lib/threading.py, line 269, in wait (self=<_Condition(_Condition__lock=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, acquire=<instancemethod at remote 0xd80260>, _is_owned=<instancemethod at remote 0xd80160>, _release_save=<instancemethod at remote 0xd803e0>, release=<instancemethod at remote 0xd802e0>, _acquire_restore=<instancemethod at remote 0xd7ee60>, _Verbose__verbose=False, _Condition__waiters=[]) at remote 0xd7fd10>, timeout=None, waiter=<thread.lock at remote 0x858860>, saved_state=(1, 140736940992272))
            self._acquire_restore(saved_state)
#12 Frame 0x7fffac001c90, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 348, in f ()
            cond.wait()
#16 Frame 0x7fffac0011c0, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 37, in task (tid=140736940992272)
                f()

Thread 1 (Thread 0x7ffff7fe2700 (LWP 10145)):
#5 Frame 0xcb5380, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 16, in _wait ()
    time.sleep(0.01)
#8 Frame 0x7fffd00024a0, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 378, in _check_notify (self=<ConditionTests(_testMethodName='test_notify', _resultForDoCleanups=<TestResult(_original_stdout=<cStringIO.StringO at remote 0xc191e0>, skipped=[], _mirrorOutput=False, testsRun=39, buffer=False, _original_stderr=<file at remote 0x7ffff7fc6340>, _stdout_buffer=<cStringIO.StringO at remote 0xc9c7f8>, _stderr_buffer=<cStringIO.StringO at remote 0xc9c790>, _moduleSetUpFailed=False, expectedFailures=[], errors=[], _previousTestClass=<type at remote 0x928310>, unexpectedSuccesses=[], failures=[], shouldStop=False, failfast=False) at remote 0xc185a0>, _threads=(0,), _cleanups=[], _type_equality_funcs={<type at remote 0x7eba00>: <instancemethod at remote 0xd750e0>, <type at remote 0x7e7820>: <instancemethod at remote 0xd75160>, <type at remote 0x7e30e0>: <instancemethod at remote 0xd75060>, <type at remote 0x7e7d20>: <instancemethod at remote 0xd751e0>, <type at remote 0x7f19e0...(truncated)
        _wait()

Enum HOWTO

An Enum is a set of symbolic names bound to unique values. They are similar to global variables, but they offer a more useful repr(), grouping, type-safety, and a few other features.

They are most useful when you have a variable that can take one of a limited selection of values. For example, the days of the week:

>>> from enum import Enum
>>> class Weekday(Enum):
...     MONDAY = 1
...     TUESDAY = 2
...     WEDNESDAY = 3
...     THURSDAY = 4
...     FRIDAY = 5
...     SATURDAY = 6
...     SUNDAY = 7

Or perhaps the RGB primary colors:

>>> from enum import Enum
>>> class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 3

As you can see, creating an Enum is as simple as writing a class that inherits from Enum itself.

참고

Case of Enum Members

Because Enums are used to represent constants, and to help avoid issues with name clashes between mixin-class methods/attributes and enum names, we strongly recommend using UPPER_CASE names for members, and will be using that style in our examples.

Depending on the nature of the enum a member’s value may or may not be important, but either way that value can be used to get the corresponding member:

>>> Weekday(3)
<Weekday.WEDNESDAY: 3>

As you can see, the repr() of a member shows the enum name, the member name, and the value. The str() of a member shows only the enum name and member name:

>>> print(Weekday.THURSDAY)
Weekday.THURSDAY

The type of an enumeration member is the enum it belongs to:

>>> type(Weekday.MONDAY)
<enum 'Weekday'>
>>> isinstance(Weekday.FRIDAY, Weekday)
True

Enum members have an attribute that contains just their name:

>>> print(Weekday.TUESDAY.name)
TUESDAY

Likewise, they have an attribute for their value:

>>> Weekday.WEDNESDAY.value
3

Unlike many languages that treat enumerations solely as name/value pairs, Python Enums can have behavior added. For example, datetime.date has two methods for returning the weekday: weekday() and isoweekday(). The difference is that one of them counts from 0-6 and the other from 1-7. Rather than keep track of that ourselves we can add a method to the Weekday enum to extract the day from the date instance and return the matching enum member:

@classmethod
def from_date(cls, date):
    return cls(date.isoweekday())

The complete Weekday enum now looks like this:

>>> class Weekday(Enum):
...     MONDAY = 1
...     TUESDAY = 2
...     WEDNESDAY = 3
...     THURSDAY = 4
...     FRIDAY = 5
...     SATURDAY = 6
...     SUNDAY = 7
...     #
...     @classmethod
...     def from_date(cls, date):
...         return cls(date.isoweekday())

Now we can find out what today is! Observe:

>>> from datetime import date
>>> Weekday.from_date(date.today())
<Weekday.TUESDAY: 2>

Of course, if you’re reading this on some other day, you’ll see that day instead.

This Weekday enum is great if our variable only needs one day, but what if we need several? Maybe we’re writing a function to plot chores during a week, and don’t want to use a list – we could use a different type of Enum:

>>> from enum import Flag
>>> class Weekday(Flag):
...     MONDAY = 1
...     TUESDAY = 2
...     WEDNESDAY = 4
...     THURSDAY = 8
...     FRIDAY = 16
...     SATURDAY = 32
...     SUNDAY = 64

We’ve changed two things: we’re inherited from Flag, and the values are all powers of 2.

Just like the original Weekday enum above, we can have a single selection:

>>> first_week_day = Weekday.MONDAY
>>> first_week_day
<Weekday.MONDAY: 1>

But Flag also allows us to combine several members into a single variable:

>>> weekend = Weekday.SATURDAY | Weekday.SUNDAY
>>> weekend
<Weekday.SATURDAY|SUNDAY: 96>

You can even iterate over a Flag variable:

>>> for day in weekend:
...     print(day)
Weekday.SATURDAY
Weekday.SUNDAY

Okay, let’s get some chores set up:

>>> chores_for_ethan = {
...     'feed the cat': Weekday.MONDAY | Weekday.WEDNESDAY | Weekday.FRIDAY,
...     'do the dishes': Weekday.TUESDAY | Weekday.THURSDAY,
...     'answer SO questions': Weekday.SATURDAY,
...     }

And a function to display the chores for a given day:

>>> def show_chores(chores, day):
...     for chore, days in chores.items():
...         if day in days:
...             print(chore)
...
>>> show_chores(chores_for_ethan, Weekday.SATURDAY)
answer SO questions

In cases where the actual values of the members do not matter, you can save yourself some work and use auto() for the values:

>>> from enum import auto
>>> class Weekday(Flag):
...     MONDAY = auto()
...     TUESDAY = auto()
...     WEDNESDAY = auto()
...     THURSDAY = auto()
...     FRIDAY = auto()
...     SATURDAY = auto()
...     SUNDAY = auto()
...     WEEKEND = SATURDAY | SUNDAY

Programmatic access to enumeration members and their attributes

Sometimes it’s useful to access members in enumerations programmatically (i.e. situations where Color.RED won’t do because the exact color is not known at program-writing time). Enum allows such access:

>>> Color(1)
<Color.RED: 1>
>>> Color(3)
<Color.BLUE: 3>

If you want to access enum members by name, use item access:

>>> Color['RED']
<Color.RED: 1>
>>> Color['GREEN']
<Color.GREEN: 2>

If you have an enum member and need its name or value:

>>> member = Color.RED
>>> member.name
'RED'
>>> member.value
1

Duplicating enum members and values

Having two enum members with the same name is invalid:

>>> class Shape(Enum):
...     SQUARE = 2
...     SQUARE = 3
...
Traceback (most recent call last):
...
TypeError: 'SQUARE' already defined as 2

However, an enum member can have other names associated with it. Given two entries A and B with the same value (and A defined first), B is an alias for the member A. By-value lookup of the value of A will return the member A. By-name lookup of A will return the member A. By-name lookup of B will also return the member A:

>>> class Shape(Enum):
...     SQUARE = 2
...     DIAMOND = 1
...     CIRCLE = 3
...     ALIAS_FOR_SQUARE = 2
...
>>> Shape.SQUARE
<Shape.SQUARE: 2>
>>> Shape.ALIAS_FOR_SQUARE
<Shape.SQUARE: 2>
>>> Shape(2)
<Shape.SQUARE: 2>

참고

Attempting to create a member with the same name as an already defined attribute (another member, a method, etc.) or attempting to create an attribute with the same name as a member is not allowed.

Ensuring unique enumeration values

By default, enumerations allow multiple names as aliases for the same value. When this behavior isn’t desired, you can use the unique() decorator:

>>> from enum import Enum, unique
>>> @unique
... class Mistake(Enum):
...     ONE = 1
...     TWO = 2
...     THREE = 3
...     FOUR = 3
...
Traceback (most recent call last):
...
ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE

Using automatic values

If the exact value is unimportant you can use auto:

>>> from enum import Enum, auto
>>> class Color(Enum):
...     RED = auto()
...     BLUE = auto()
...     GREEN = auto()
...
>>> [member.value for member in Color]
[1, 2, 3]

The values are chosen by _generate_next_value_(), which can be overridden:

>>> class AutoName(Enum):
...     @staticmethod
...     def _generate_next_value_(name, start, count, last_values):
...         return name
...
>>> class Ordinal(AutoName):
...     NORTH = auto()
...     SOUTH = auto()
...     EAST = auto()
...     WEST = auto()
...
>>> [member.value for member in Ordinal]
['NORTH', 'SOUTH', 'EAST', 'WEST']

참고

The _generate_next_value_() method must be defined before any members.

Iteration

Iterating over the members of an enum does not provide the aliases:

>>> list(Shape)
[<Shape.SQUARE: 2>, <Shape.DIAMOND: 1>, <Shape.CIRCLE: 3>]
>>> list(Weekday)
[<Weekday.MONDAY: 1>, <Weekday.TUESDAY: 2>, <Weekday.WEDNESDAY: 4>, <Weekday.THURSDAY: 8>, <Weekday.FRIDAY: 16>, <Weekday.SATURDAY: 32>, <Weekday.SUNDAY: 64>]

Note that the aliases Shape.ALIAS_FOR_SQUARE and Weekday.WEEKEND aren’t shown.

The special attribute __members__ is a read-only ordered mapping of names to members. It includes all names defined in the enumeration, including the aliases:

>>> for name, member in Shape.__members__.items():
...     name, member
...
('SQUARE', <Shape.SQUARE: 2>)
('DIAMOND', <Shape.DIAMOND: 1>)
('CIRCLE', <Shape.CIRCLE: 3>)
('ALIAS_FOR_SQUARE', <Shape.SQUARE: 2>)

The __members__ attribute can be used for detailed programmatic access to the enumeration members. For example, finding all the aliases:

>>> [name for name, member in Shape.__members__.items() if member.name != name]
['ALIAS_FOR_SQUARE']

참고

Aliases for flags include values with multiple flags set, such as 3, and no flags set, i.e. 0.

Comparisons

Enumeration members are compared by identity:

>>> Color.RED is Color.RED
True
>>> Color.RED is Color.BLUE
False
>>> Color.RED is not Color.BLUE
True

Ordered comparisons between enumeration values are not supported. Enum members are not integers (but see IntEnum below):

>>> Color.RED < Color.BLUE
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: '<' not supported between instances of 'Color' and 'Color'

Equality comparisons are defined though:

>>> Color.BLUE == Color.RED
False
>>> Color.BLUE != Color.RED
True
>>> Color.BLUE == Color.BLUE
True

Comparisons against non-enumeration values will always compare not equal (again, IntEnum was explicitly designed to behave differently, see below):

>>> Color.BLUE == 2
False

경고

It is possible to reload modules – if a reloaded module contains enums, they will be recreated, and the new members may not compare identical/equal to the original members.

Allowed members and attributes of enumerations

Most of the examples above use integers for enumeration values. Using integers is short and handy (and provided by default by the Functional API), but not strictly enforced. In the vast majority of use-cases, one doesn’t care what the actual value of an enumeration is. But if the value is important, enumerations can have arbitrary values.

Enumerations are Python classes, and can have methods and special methods as usual. If we have this enumeration:

>>> class Mood(Enum):
...     FUNKY = 1
...     HAPPY = 3
...
...     def describe(self):
...         # self is the member here
...         return self.name, self.value
...
...     def __str__(self):
...         return 'my custom str! {0}'.format(self.value)
...
...     @classmethod
...     def favorite_mood(cls):
...         # cls here is the enumeration
...         return cls.HAPPY
...

Then:

>>> Mood.favorite_mood()
<Mood.HAPPY: 3>
>>> Mood.HAPPY.describe()
('HAPPY', 3)
>>> str(Mood.FUNKY)
'my custom str! 1'

The rules for what is allowed are as follows: names that start and end with a single underscore are reserved by enum and cannot be used; all other attributes defined within an enumeration will become members of this enumeration, with the exception of special methods (__str__(), __add__(), etc.), descriptors (methods are also descriptors), and variable names listed in _ignore_.

Note: if your enumeration defines __new__() and/or __init__(), any value(s) given to the enum member will be passed into those methods. See Planet for an example.

참고

The __new__() method, if defined, is used during creation of the Enum members; it is then replaced by Enum’s __new__() which is used after class creation for lookup of existing members. See When to use __new__() vs. __init__() for more details.

Restricted Enum subclassing

A new Enum class must have one base enum class, up to one concrete data type, and as many object-based mixin classes as needed. The order of these base classes is:

class EnumName([mix-in, ...,] [data-type,] base-enum):
    pass

Also, subclassing an enumeration is allowed only if the enumeration does not define any members. So this is forbidden:

>>> class MoreColor(Color):
...     PINK = 17
...
Traceback (most recent call last):
...
TypeError: <enum 'MoreColor'> cannot extend <enum 'Color'>

But this is allowed:

>>> class Foo(Enum):
...     def some_behavior(self):
...         pass
...
>>> class Bar(Foo):
...     HAPPY = 1
...     SAD = 2
...

Allowing subclassing of enums that define members would lead to a violation of some important invariants of types and instances. On the other hand, it makes sense to allow sharing some common behavior between a group of enumerations. (See OrderedEnum for an example.)

Dataclass support

When inheriting from a dataclass, the __repr__() omits the inherited class’ name. For example:

>>> from dataclasses import dataclass, field
>>> @dataclass
... class CreatureDataMixin:
...     size: str
...     legs: int
...     tail: bool = field(repr=False, default=True)
...
>>> class Creature(CreatureDataMixin, Enum):
...     BEETLE = 'small', 6
...     DOG = 'medium', 4
...
>>> Creature.DOG
<Creature.DOG: size='medium', legs=4>

Use the dataclass() argument repr=False to use the standard repr().

버전 3.12에서 변경: Only the dataclass fields are shown in the value area, not the dataclass’ name.

참고

Adding dataclass() decorator to Enum and its subclasses is not supported. It will not raise any errors, but it will produce very strange results at runtime, such as members being equal to each other:

>>> @dataclass               # don't do this: it does not make any sense
... class Color(Enum):
...    RED = 1
...    BLUE = 2
...
>>> Color.RED is Color.BLUE
False
>>> Color.RED == Color.BLUE  # problem is here: they should not be equal
True

Pickling

Enumerations can be pickled and unpickled:

>>> from test.test_enum import Fruit
>>> from pickle import dumps, loads
>>> Fruit.TOMATO is loads(dumps(Fruit.TOMATO))
True

The usual restrictions for pickling apply: picklable enums must be defined in the top level of a module, since unpickling requires them to be importable from that module.

참고

With pickle protocol version 4 it is possible to easily pickle enums nested in other classes.

It is possible to modify how enum members are pickled/unpickled by defining __reduce_ex__() in the enumeration class. The default method is by-value, but enums with complicated values may want to use by-name:

>>> import enum
>>> class MyEnum(enum.Enum):
...     __reduce_ex__ = enum.pickle_by_enum_name

참고

Using by-name for flags is not recommended, as unnamed aliases will not unpickle.

Functional API

The Enum class is callable, providing the following functional API:

>>> Animal = Enum('Animal', 'ANT BEE CAT DOG')
>>> Animal
<enum 'Animal'>
>>> Animal.ANT
<Animal.ANT: 1>
>>> list(Animal)
[<Animal.ANT: 1>, <Animal.BEE: 2>, <Animal.CAT: 3>, <Animal.DOG: 4>]

The semantics of this API resemble namedtuple. The first argument of the call to Enum is the name of the enumeration.

The second argument is the source of enumeration member names. It can be a whitespace-separated string of names, a sequence of names, a sequence of 2-tuples with key/value pairs, or a mapping (e.g. dictionary) of names to values. The last two options enable assigning arbitrary values to enumerations; the others auto-assign increasing integers starting with 1 (use the start parameter to specify a different starting value). A new class derived from Enum is returned. In other words, the above assignment to Animal is equivalent to:

>>> class Animal(Enum):
...     ANT = 1
...     BEE = 2
...     CAT = 3
...     DOG = 4
...

The reason for defaulting to 1 as the starting number and not 0 is that 0 is False in a boolean sense, but by default enum members all evaluate to True.

Pickling enums created with the functional API can be tricky as frame stack implementation details are used to try and figure out which module the enumeration is being created in (e.g. it will fail if you use a utility function in a separate module, and also may not work on IronPython or Jython). The solution is to specify the module name explicitly as follows:

>>> Animal = Enum('Animal', 'ANT BEE CAT DOG', module=__name__)

경고

If module is not supplied, and Enum cannot determine what it is, the new Enum members will not be unpicklable; to keep errors closer to the source, pickling will be disabled.

The new pickle protocol 4 also, in some circumstances, relies on __qualname__ being set to the location where pickle will be able to find the class. For example, if the class was made available in class SomeData in the global scope:

>>> Animal = Enum('Animal', 'ANT BEE CAT DOG', qualname='SomeData.Animal')

The complete signature is:

Enum(
    value='NewEnumName',
    names=<...>,
    *,
    module='...',
    qualname='...',
    type=<mixed-in class>,
    start=1,
    )

value: What the new enum class will record as its name.

names: The enum members. This can be a whitespace- or comma-separated string (values will start at 1 unless otherwise specified):

'RED GREEN BLUE' | 'RED,GREEN,BLUE' | 'RED, GREEN, BLUE'

or an iterator of names:

['RED', 'GREEN', 'BLUE']

or an iterator of (name, value) pairs:

[('CYAN', 4), ('MAGENTA', 5), ('YELLOW', 6)]

or a mapping:

{'CHARTREUSE': 7, 'SEA_GREEN': 11, 'ROSEMARY': 42}

module: name of module where new enum class can be found.

qualname: where in module new enum class can be found.

type: type to mix in to new enum class.

start: number to start counting at if only names are passed in.

버전 3.5에서 변경: The start parameter was added.

Derived Enumerations

IntEnum

The first variation of Enum that is provided is also a subclass of int. Members of an IntEnum can be compared to integers; by extension, integer enumerations of different types can also be compared to each other:

>>> from enum import IntEnum
>>> class Shape(IntEnum):
...     CIRCLE = 1
...     SQUARE = 2
...
>>> class Request(IntEnum):
...     POST = 1
...     GET = 2
...
>>> Shape == 1
False
>>> Shape.CIRCLE == 1
True
>>> Shape.CIRCLE == Request.POST
True

However, they still can’t be compared to standard Enum enumerations:

>>> class Shape(IntEnum):
...     CIRCLE = 1
...     SQUARE = 2
...
>>> class Color(Enum):
...     RED = 1
...     GREEN = 2
...
>>> Shape.CIRCLE == Color.RED
False

IntEnum values behave like integers in other ways you’d expect:

>>> int(Shape.CIRCLE)
1
>>> ['a', 'b', 'c'][Shape.CIRCLE]
'b'
>>> [i for i in range(Shape.SQUARE)]
[0, 1]

StrEnum

The second variation of Enum that is provided is also a subclass of str. Members of a StrEnum can be compared to strings; by extension, string enumerations of different types can also be compared to each other.

Added in version 3.11.

IntFlag

The next variation of Enum provided, IntFlag, is also based on int. The difference being IntFlag members can be combined using the bitwise operators (&, |, ^, ~) and the result is still an IntFlag member, if possible. Like IntEnum, IntFlag members are also integers and can be used wherever an int is used.

참고

Any operation on an IntFlag member besides the bit-wise operations will lose the IntFlag membership.

Bit-wise operations that result in invalid IntFlag values will lose the IntFlag membership. See FlagBoundary for details.

Added in version 3.6.

버전 3.11에서 변경.

Sample IntFlag class:

>>> from enum import IntFlag
>>> class Perm(IntFlag):
...     R = 4
...     W = 2
...     X = 1
...
>>> Perm.R | Perm.W
<Perm.R|W: 6>
>>> Perm.R + Perm.W
6
>>> RW = Perm.R | Perm.W
>>> Perm.R in RW
True

It is also possible to name the combinations:

>>> class Perm(IntFlag):
...     R = 4
...     W = 2
...     X = 1
...     RWX = 7
...
>>> Perm.RWX
<Perm.RWX: 7>
>>> ~Perm.RWX
<Perm: 0>
>>> Perm(7)
<Perm.RWX: 7>

참고

Named combinations are considered aliases. Aliases do not show up during iteration, but can be returned from by-value lookups.

버전 3.11에서 변경.

Another important difference between IntFlag and Enum is that if no flags are set (the value is 0), its boolean evaluation is False:

>>> Perm.R & Perm.X
<Perm: 0>
>>> bool(Perm.R & Perm.X)
False

Because IntFlag members are also subclasses of int they can be combined with them (but may lose IntFlag membership:

>>> Perm.X | 4
<Perm.R|X: 5>

>>> Perm.X + 8
9

참고

The negation operator, ~, always returns an IntFlag member with a positive value:

>>> (~Perm.X).value == (Perm.R|Perm.W).value == 6
True

IntFlag members can also be iterated over:

>>> list(RW)
[<Perm.R: 4>, <Perm.W: 2>]

Added in version 3.11.

Flag

The last variation is Flag. Like IntFlag, Flag members can be combined using the bitwise operators (&, |, ^, ~). Unlike IntFlag, they cannot be combined with, nor compared against, any other Flag enumeration, nor int. While it is possible to specify the values directly it is recommended to use auto as the value and let Flag select an appropriate value.

Added in version 3.6.

Like IntFlag, if a combination of Flag members results in no flags being set, the boolean evaluation is False:

>>> from enum import Flag, auto
>>> class Color(Flag):
...     RED = auto()
...     BLUE = auto()
...     GREEN = auto()
...
>>> Color.RED & Color.GREEN
<Color: 0>
>>> bool(Color.RED & Color.GREEN)
False

Individual flags should have values that are powers of two (1, 2, 4, 8, …), while combinations of flags will not:

>>> class Color(Flag):
...     RED = auto()
...     BLUE = auto()
...     GREEN = auto()
...     WHITE = RED | BLUE | GREEN
...
>>> Color.WHITE
<Color.WHITE: 7>

Giving a name to the “no flags set” condition does not change its boolean value:

>>> class Color(Flag):
...     BLACK = 0
...     RED = auto()
...     BLUE = auto()
...     GREEN = auto()
...
>>> Color.BLACK
<Color.BLACK: 0>
>>> bool(Color.BLACK)
False

Flag members can also be iterated over:

>>> purple = Color.RED | Color.BLUE
>>> list(purple)
[<Color.RED: 1>, <Color.BLUE: 2>]

Added in version 3.11.

참고

For the majority of new code, Enum and Flag are strongly recommended, since IntEnum and IntFlag break some semantic promises of an enumeration (by being comparable to integers, and thus by transitivity to other unrelated enumerations). IntEnum and IntFlag should be used only in cases where Enum and Flag will not do; for example, when integer constants are replaced with enumerations, or for interoperability with other systems.

Others

While IntEnum is part of the enum module, it would be very simple to implement independently:

class IntEnum(int, ReprEnum):   # or Enum instead of ReprEnum
    pass

This demonstrates how similar derived enumerations can be defined; for example a FloatEnum that mixes in float instead of int.

Some rules:

When subclassing Enum, mix-in types must appear before the Enum class itself in the sequence of bases, as in the IntEnum example above.

Mix-in types must be subclassable. For example, bool and range are not subclassable and will throw an error during Enum creation if used as the mix-in type.

While Enum can have members of any type, once you mix in an additional type, all the members must have values of that type, e.g. int above. This restriction does not apply to mix-ins which only add methods and don’t specify another type.

When another data type is mixed in, the value attribute is not the same as the enum member itself, although it is equivalent and will compare equal.

A data type is a mixin that defines __new__(), or a dataclass

%-style formatting: %s and %r call the Enum class’s __str__() and __repr__() respectively; other codes (such as %i or %h for IntEnum) treat the enum member as its mixed-in type.

Formatted string literals, str.format(), and format() will use the enum’s __str__() method.

참고

Because IntEnum, IntFlag, and StrEnum are designed to be drop-in replacements for existing constants, their __str__() method has been reset to their data types’ __str__() method.

When to use __new__() vs. __init__()

__new__() must be used whenever you want to customize the actual value of the Enum member. Any other modifications may go in either __new__() or __init__(), with __init__() being preferred.

For example, if you want to pass several items to the constructor, but only want one of them to be the value:

>>> class Coordinate(bytes, Enum):
...     """
...     Coordinate with binary codes that can be indexed by the int code.
...     """
...     def __new__(cls, value, label, unit):
...         obj = bytes.__new__(cls, [value])
...         obj._value_ = value
...         obj.label = label
...         obj.unit = unit
...         return obj
...     PX = (0, 'P.X', 'km')
...     PY = (1, 'P.Y', 'km')
...     VX = (2, 'V.X', 'km/s')
...     VY = (3, 'V.Y', 'km/s')
...

>>> print(Coordinate['PY'])
Coordinate.PY

>>> print(Coordinate(3))
Coordinate.VY

경고

Do not call super().__new__(), as the lookup-only __new__ is the one that is found; instead, use the data type directly.

Finer Points

Supported __dunder__ names

__members__ is a read-only ordered mapping of member_name:member items. It is only available on the class.

__new__(), if specified, must create and return the enum members; it is also a very good idea to set the member’s _value_ appropriately. Once all the members are created it is no longer used.

Supported _sunder_ names

_name_ – name of the member

_value_ – value of the member; can be set in __new__

_missing_() – a lookup function used when a value is not found; may be overridden

_ignore_ – a list of names, either as a list or a str, that will not be transformed into members, and will be removed from the final class

_generate_next_value_() – used to get an appropriate value for an enum member; may be overridden

_add_alias_() – adds a new name as an alias to an existing member.

_add_value_alias_() – adds a new value as an alias to an existing member. See MultiValueEnum for an example.

참고

For standard Enum classes the next value chosen is the highest value seen incremented by one.

For Flag classes the next value chosen will be the next highest power-of-two.

버전 3.13에서 변경: Prior versions would use the last seen value instead of the highest value.

Added in version 3.6: _missing_, _order_, _generate_next_value_

Added in version 3.7: _ignore_

Added in version 3.13: _add_alias_, _add_value_alias_

To help keep Python 2 / Python 3 code in sync an _order_ attribute can be provided. It will be checked against the actual order of the enumeration and raise an error if the two do not match:

>>> class Color(Enum):
...     _order_ = 'RED GREEN BLUE'
...     RED = 1
...     BLUE = 3
...     GREEN = 2
...
Traceback (most recent call last):
...
TypeError: member order does not match _order_:
  ['RED', 'BLUE', 'GREEN']
  ['RED', 'GREEN', 'BLUE']

참고

In Python 2 code the _order_ attribute is necessary as definition order is lost before it can be recorded.

_Private__names

Private names are not converted to enum members, but remain normal attributes.

버전 3.11에서 변경.

Enum member type

Enum members are instances of their enum class, and are normally accessed as EnumClass.member. In certain situations, such as writing custom enum behavior, being able to access one member directly from another is useful, and is supported; however, in order to avoid name clashes between member names and attributes/methods from mixed-in classes, upper-case names are strongly recommended.

버전 3.5에서 변경.

Creating members that are mixed with other data types

When subclassing other data types, such as int or str, with an Enum, all values after the = are passed to that data type’s constructor. For example:

>>> class MyEnum(IntEnum):      # help(int) -> int(x, base=10) -> integer
...     example = '11', 16      # so x='11' and base=16
...
>>> MyEnum.example.value        # and hex(11) is...
17

Boolean value of Enum classes and members

Enum classes that are mixed with non-Enum types (such as int, str, etc.) are evaluated according to the mixed-in type’s rules; otherwise, all members evaluate as True. To make your own enum’s boolean evaluation depend on the member’s value add the following to your class:

def __bool__(self):
    return bool(self.value)

Plain Enum classes always evaluate as True.

Enum classes with methods

If you give your enum subclass extra methods, like the Planet class below, those methods will show up in a dir() of the member, but not of the class:

>>> dir(Planet)
['EARTH', 'JUPITER', 'MARS', 'MERCURY', 'NEPTUNE', 'SATURN', 'URANUS', 'VENUS', '__class__', '__doc__', '__members__', '__module__']
>>> dir(Planet.EARTH)
['__class__', '__doc__', '__module__', 'mass', 'name', 'radius', 'surface_gravity', 'value']

Combining members of Flag

Iterating over a combination of Flag members will only return the members that are comprised of a single bit:

>>> class Color(Flag):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
...     MAGENTA = RED | BLUE
...     YELLOW = RED | GREEN
...     CYAN = GREEN | BLUE
...
>>> Color(3)  # named combination
<Color.YELLOW: 3>
>>> Color(7)      # not named combination
<Color.RED|GREEN|BLUE: 7>

Flag and IntFlag minutia

Using the following snippet for our examples:

>>> class Color(IntFlag):
...     BLACK = 0
...     RED = 1
...     GREEN = 2
...     BLUE = 4
...     PURPLE = RED | BLUE
...     WHITE = RED | GREEN | BLUE
...

the following are true:

single-bit flags are canonical

multi-bit and zero-bit flags are aliases

only canonical flags are returned during iteration:

>>> list(Color.WHITE)
[<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 4>]

negating a flag or flag set returns a new flag/flag set with the corresponding positive integer value:

>>> Color.BLUE
<Color.BLUE: 4>

>>> ~Color.BLUE
<Color.RED|GREEN: 3>

names of pseudo-flags are constructed from their members’ names:

>>> (Color.RED | Color.GREEN).name
'RED|GREEN'

>>> class Perm(IntFlag):
...     R = 4
...     W = 2
...     X = 1
...
>>> (Perm.R & Perm.W).name is None  # effectively Perm(0)
True

multi-bit flags, aka aliases, can be returned from operations:

>>> Color.RED | Color.BLUE
<Color.PURPLE: 5>

>>> Color(7)  # or Color(-1)
<Color.WHITE: 7>

>>> Color(0)
<Color.BLACK: 0>

membership / containment checking: zero-valued flags are always considered to be contained:

>>> Color.BLACK in Color.WHITE
True

otherwise, only if all bits of one flag are in the other flag will True be returned:

>>> Color.PURPLE in Color.WHITE
True

>>> Color.GREEN in Color.PURPLE
False

There is a new boundary mechanism that controls how out-of-range / invalid bits are handled: STRICT, CONFORM, EJECT, and KEEP:

STRICT –> raises an exception when presented with invalid values

CONFORM –> discards any invalid bits

EJECT –> lose Flag status and become a normal int with the given value

KEEP –> keep the extra bits

keeps Flag status and extra bits

extra bits do not show up in iteration

extra bits do show up in repr() and str()

The default for Flag is STRICT, the default for IntFlag is EJECT, and the default for _convert_ is KEEP (see ssl.Options for an example of when KEEP is needed).

How are Enums and Flags different?

Enums have a custom metaclass that affects many aspects of both derived Enum classes and their instances (members).

Enum Classes

The EnumType metaclass is responsible for providing the __contains__(), __dir__(), __iter__() and other methods that allow one to do things with an Enum class that fail on a typical class, such as list(Color) or some_enum_var in Color. EnumType is responsible for ensuring that various other methods on the final Enum class are correct (such as __new__(), __getnewargs__(), __str__() and __repr__()).

Flag Classes

Flags have an expanded view of aliasing: to be canonical, the value of a flag needs to be a power-of-two value, and not a duplicate name. So, in addition to the Enum definition of alias, a flag with no value (a.k.a. 0) or with more than one power-of-two value (e.g. 3) is considered an alias.

Enum Members (aka instances)

The most interesting thing about enum members is that they are singletons. EnumType creates them all while it is creating the enum class itself, and then puts a custom __new__() in place to ensure that no new ones are ever instantiated by returning only the existing member instances.

Flag Members

Flag members can be iterated over just like the Flag class, and only the canonical members will be returned. For example:

>>> list(Color)
[<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 4>]

(Note that BLACK, PURPLE, and WHITE do not show up.)

Inverting a flag member returns the corresponding positive value, rather than a negative value — for example:

>>> ~Color.RED
<Color.GREEN|BLUE: 6>

Flag members have a length corresponding to the number of power-of-two values they contain. For example:

>>> len(Color.PURPLE)
2

Enum Cookbook

While Enum, IntEnum, StrEnum, Flag, and IntFlag are expected to cover the majority of use-cases, they cannot cover them all. Here are recipes for some different types of enumerations that can be used directly, or as examples for creating one’s own.

Omitting values

In many use-cases, one doesn’t care what the actual value of an enumeration is. There are several ways to define this type of simple enumeration:

use instances of auto for the value

use instances of object as the value

use a descriptive string as the value

use a tuple as the value and a custom __new__() to replace the tuple with an int value

Using any of these methods signifies to the user that these values are not important, and also enables one to add, remove, or reorder members without having to renumber the remaining members.

Using auto

Using auto would look like:

>>> class Color(Enum):
...     RED = auto()
...     BLUE = auto()
...     GREEN = auto()
...
>>> Color.GREEN
<Color.GREEN: 3>

Using object

Using object would look like:

>>> class Color(Enum):
...     RED = object()
...     GREEN = object()
...     BLUE = object()
...
>>> Color.GREEN
<Color.GREEN: <object object at 0x...>>

This is also a good example of why you might want to write your own __repr__():

>>> class Color(Enum):
...     RED = object()
...     GREEN = object()
...     BLUE = object()
...     def __repr__(self):
...         return "<%s.%s>" % (self.__class__.__name__, self._name_)
...
>>> Color.GREEN
<Color.GREEN>

Using a descriptive string

Using a string as the value would look like:

>>> class Color(Enum):
...     RED = 'stop'
...     GREEN = 'go'
...     BLUE = 'too fast!'
...
>>> Color.GREEN
<Color.GREEN: 'go'>

Using a custom __new__()

Using an auto-numbering __new__() would look like:

>>> class AutoNumber(Enum):
...     def __new__(cls):
...         value = len(cls.__members__) + 1
...         obj = object.__new__(cls)
...         obj._value_ = value
...         return obj
...
>>> class Color(AutoNumber):
...     RED = ()
...     GREEN = ()
...     BLUE = ()
...
>>> Color.GREEN
<Color.GREEN: 2>

To make a more general purpose AutoNumber, add *args to the signature:

>>> class AutoNumber(Enum):
...     def __new__(cls, *args):      # this is the only change from above
...         value = len(cls.__members__) + 1
...         obj = object.__new__(cls)
...         obj._value_ = value
...         return obj
...

Then when you inherit from AutoNumber you can write your own __init__ to handle any extra arguments:

>>> class Swatch(AutoNumber):
...     def __init__(self, pantone='unknown'):
...         self.pantone = pantone
...     AUBURN = '3497'
...     SEA_GREEN = '1246'
...     BLEACHED_CORAL = () # New color, no Pantone code yet!
...
>>> Swatch.SEA_GREEN
<Swatch.SEA_GREEN: 2>
>>> Swatch.SEA_GREEN.pantone
'1246'
>>> Swatch.BLEACHED_CORAL.pantone
'unknown'

참고

The __new__() method, if defined, is used during creation of the Enum members; it is then replaced by Enum’s __new__() which is used after class creation for lookup of existing members.

경고

Do not call super().__new__(), as the lookup-only __new__ is the one that is found; instead, use the data type directly – e.g.:

obj = int.__new__(cls, value)

OrderedEnum

An ordered enumeration that is not based on IntEnum and so maintains the normal Enum invariants (such as not being comparable to other enumerations):

>>> class OrderedEnum(Enum):
...     def __ge__(self, other):
...         if self.__class__ is other.__class__:
...             return self.value >= other.value
...         return NotImplemented
...     def __gt__(self, other):
...         if self.__class__ is other.__class__:
...             return self.value > other.value
...         return NotImplemented
...     def __le__(self, other):
...         if self.__class__ is other.__class__:
...             return self.value <= other.value
...         return NotImplemented
...     def __lt__(self, other):
...         if self.__class__ is other.__class__:
...             return self.value < other.value
...         return NotImplemented
...
>>> class Grade(OrderedEnum):
...     A = 5
...     B = 4
...     C = 3
...     D = 2
...     F = 1
...
>>> Grade.C < Grade.A
True

DuplicateFreeEnum

Raises an error if a duplicate member value is found instead of creating an alias:

>>> class DuplicateFreeEnum(Enum):
...     def __init__(self, *args):
...         cls = self.__class__
...         if any(self.value == e.value for e in cls):
...             a = self.name
...             e = cls(self.value).name
...             raise ValueError(
...                 "aliases not allowed in DuplicateFreeEnum:  %r --> %r"
...                 % (a, e))
...
>>> class Color(DuplicateFreeEnum):
...     RED = 1
...     GREEN = 2
...     BLUE = 3
...     GRENE = 2
...
Traceback (most recent call last):
  ...
ValueError: aliases not allowed in DuplicateFreeEnum:  'GRENE' --> 'GREEN'

참고

This is a useful example for subclassing Enum to add or change other behaviors as well as disallowing aliases. If the only desired change is disallowing aliases, the unique() decorator can be used instead.

MultiValueEnum

Supports having more than one value per member:

>>> class MultiValueEnum(Enum):
...     def __new__(cls, value, *values):
...         self = object.__new__(cls)
...         self._value_ = value
...         for v in values:
...             self._add_value_alias_(v)
...         return self
...
>>> class DType(MultiValueEnum):
...     float32 = 'f', 8
...     double64 = 'd', 9
...
>>> DType('f')
<DType.float32: 'f'>
>>> DType(9)
<DType.double64: 'd'>

Planet

If __new__() or __init__() is defined, the value of the enum member will be passed to those methods:

>>> class Planet(Enum):
...     MERCURY = (3.303e+23, 2.4397e6)
...     VENUS   = (4.869e+24, 6.0518e6)
...     EARTH   = (5.976e+24, 6.37814e6)
...     MARS    = (6.421e+23, 3.3972e6)
...     JUPITER = (1.9e+27,   7.1492e7)
...     SATURN  = (5.688e+26, 6.0268e7)
...     URANUS  = (8.686e+25, 2.5559e7)
...     NEPTUNE = (1.024e+26, 2.4746e7)
...     def __init__(self, mass, radius):
...         self.mass = mass       # in kilograms
...         self.radius = radius   # in meters
...     @property
...     def surface_gravity(self):
...         # universal gravitational constant  (m3 kg-1 s-2)
...         G = 6.67300E-11
...         return G * self.mass / (self.radius * self.radius)
...
>>> Planet.EARTH.value
(5.976e+24, 6378140.0)
>>> Planet.EARTH.surface_gravity
9.802652743337129

TimePeriod

An example to show the _ignore_ attribute in use:

>>> from datetime import timedelta
>>> class Period(timedelta, Enum):
...     "different lengths of time"
...     _ignore_ = 'Period i'
...     Period = vars()
...     for i in range(367):
...         Period['day_%d' % i] = i
...
>>> list(Period)[:2]
[<Period.day_0: datetime.timedelta(0)>, <Period.day_1: datetime.timedelta(days=1)>]
>>> list(Period)[-2:]
[<Period.day_365: datetime.timedelta(days=365)>, <Period.day_366: datetime.timedelta(days=366)>]

Subclassing EnumType

While most enum needs can be met by customizing Enum subclasses, either with class decorators or custom functions, EnumType can be subclassed to provide a different Enum experience.

함수형 프로그래밍 HOWTO

저자:

A. M. Kuchling

버전:

0.32

이 문서에서는, 함수형 방식으로 프로그램을 구현하는데 적합한 파이썬의 특성에 대해 알아볼 것입니다. 함수형 프로그래밍의 개념을 소개한 뒤에, 이터레이터 , 제너레이터 와 같은 언어의 특성과 itertools , functools 와 같은 관련 라이브러리 모듈을 살펴볼 것입니다.

소개

이 절에서는 함수형 프로그래밍의 기본적인 개념을 설명합니다; 만약 단순히 파이썬의 언어적 특성에 관해서만 관심이 있으시다면, 이터레이터 절로 건너뛰세요.

프로그래밍 언어들은 다음과 같이 각각 다른 방식으로 문제를 더 작은 부분으로 분할하는 방법을 지원합니다:

대부분의 프로그래밍 언어들은 절차적 입니다: 프로그램은 컴퓨터에 프로그램의 입력을 어떻게 할지 알려주는 명령 목록입니다. C, 파스칼, 유닉스 셸과 같은 것들은 절차적 언어입니다.

선언적 언어에서는 해결해야 할 문제를 설명하는 명세서를 작성하고, 언어 구현은 계산을 효과적으로 수행하는 방법을 파악합니다. SQL은 가장 친숙한 선언적 언어입니다; SQL 질의는 검색하고 싶은 데이터 세트를 설명하고, SQL 엔진은 테이블을 스캔하거나 인덱스를 사용할 것인지, 어떤 하위 구문을 먼저 수행해야 하는지 등을 결정합니다.

객체지향 프로그램은 객체들의 컬렉션을 다룹니다. 객체는 내부적인 상태를 갖고 있으며 이 내부적인 상태를 어떤 방식으로 가져오거나 수정하는 메서드를 제공합니다. 스몰토크와 자바는 객체지향 언어입니다. C++ 와 파이썬은 객체지향 프로그래밍을 지원하는 언어이지만, 객체 지향적인 특성들을 사용하도록 강제하지는 않습니다.

함수형 프로그래밍은 함수들의 세트로 문제를 분해합니다. 이상적으로 말하면, 함수들은 입력을 받아서 출력을 만들어내기만 하며, 주어진 입력에 대해 생성된 출력에 영향을 끼칠만한 어떠한 내부적인 상태도 가지지 않습니다. 잘 알려진 함수형 언어로는 ML 계열(Standard ML, OCaml 및 다른 변형)과 하스켈이 있습니다.

일부 컴퓨터 언어의 설계자들은 프로그래밍에 대한 한 가지의 특별한 접근 방식을 강조합니다. 이것은 종종 다른 접근 방식으로 프로그램을 작성하는 것을 어렵게 만듭니다. 다른 언어들은 다양한 접근 방법을 지원하는 다중 패러다임 언어입니다. Lisp, C++, 파이썬 등은 다중 패러다임 언어입니다; 이러한 언어에서는 절차적, 객체 지향적 혹은 함수형으로 프로그램이나 라이브러리를 작성할 수 있습니다. 거대한 프로그램에서, 각 구역은 서로 다른 접근 방법을 사용하여 작성될 수 있습니다; 예를 들어 처리 로직이 절차적 혹은 함수형으로 작성되었을 때, GUI는 객체 지향적으로 작성될 수 있습니다.

함수형 프로그램에서, 입력은 여러 함수의 세트를 통해 흘러 다닙니다. 각 함수는 입력으로부터 동작해서 출력을 만들어냅니다. 함수형 방식은 내부 상태를 수정하거나 함수의 반환 값에서 보이지 않는 다른 변경사항들을 만드는 부작용이 있는 함수를 사용하지 않습니다. 부작용이 전혀 없는 함수를 순수 함수 라고 합니다. 부작용을 피한다는 것은 프로그램이 실행될 때 수정될 수 있는 자료 구조를 사용하지 않는다는 의미입니다; 모든 함수의 출력은 입력에만 의존해야 합니다.

Some languages are very strict about purity and don’t even have assignment statements such as a=3 or c = a + b, but it’s difficult to avoid all side effects, such as printing to the screen or writing to a disk file. Another example is a call to the print() or time.sleep() function, neither of which returns a useful value. Both are called only for their side effects of sending some text to the screen or pausing execution for a second.

함수형 방식으로 작성된 파이썬 프로그램은 보통 극단적으로 모든 I/O 혹은 대입문을 회피하는 방식으로 나아가지는 않습니다; 대신 함수형처럼 보이는 인터페이스를 제공하며 내부적으로는 함수형이 아닌 기능들을 사용합니다. 예를 들어 함수의 구현은 여전히 지역 변수에 값을 대입하는 방식이 사용되지만 전역 변수를 수정하거나 다른 부작용을 발생시키지는 않습니다.

함수형 프로그래밍은 객체 지향 프로그래밍의 반대라고 생각할 수 있습니다. 객체는 내부 상태들을 갖고 있으며 이 상태들을 수정할 수 있는 메서드의 호출 모음이 포함된 작은 캡슐이며, 프로그램은 올바른 상태 변경 집합을 구성합니다. 함수형 프로그래밍은 가능한 한 상태 변경을 피하고자 하며 함수 간의 데이터 흐름을 사용합니다. 파이썬에서는 응용 프로그램의 객체를 나타내는 인스턴스(전자 우편 메시지, 트랜잭션 등)를 가져와서 반환하는 함수를 작성함으로써 두 가지 접근 방식을 결합할 수 있습니다.

함수형 설계는 동작 방식에 이상한 제약이 있는 것처럼 보일 수 있습니다. 왜 객체와 부작용을 피해야만 할까요? 함수형 방식은 이론적으로도, 실질적으로도 다음과 같은 장점이 있습니다:

형식적 증명 가능성.

모듈성.

결합성.

디버깅과 테스트 용이성.

형식적 증명 가능성

이론적인 장점은 함수형 프로그램이 정확하다는 수학적 증명을 만드는 것이 더 쉽다는 것입니다.

오랫동안 연구자들은 수학적으로 프로그램이 정확하다는 것을 증명하는 방법을 찾는 데 관심을 보여왔습니다. 이것은 수많은 입력에 대해 프로그램을 테스트하고 출력이 정확하다고 결론짓거나, 프로그램의 소스코드를 읽어보고 코드가 올바르다고 결론짓는 것과는 다릅니다; 그들의 목표는 입력 가능한 모든 것에 대해 프로그램이 올바른 결과를 산출한다는 엄격한 증거를 찾는 것입니다.

프로그램이 올바른지 증명하기 위해 사용하는 기술은 항상 참인 입력 데이터와 프로그램의 변수라는 특성을 지닌 불변자 를 작성하는 것입니다. 각 코드 행에 대해, 그 행이 실행되기 전에 불변자 X와 Y가 참이라면, 그 행이 실행된 후에 약간 다른 불변자 X’ 및 Y’가 참이라는 것을 보여줍니다. 이 작업은 프로그램이 종료될 때까지 계속되며, 종료 시점에서 불변자는 프로그램의 출력으로써 원하는 조건과 일치해야만 합니다.

함수형 프로그래밍에서 값 대입을 피하려는 이유는 값 대입이 이러한 기법을 활용하는 것을 어렵게 만들기 때문입니다; 대입은 다음 단계로 나아갈 수 있는 새 불변자를 만들지 않은 채로, 대입전에 참이었던 불변자를 무너뜨릴 수 있습니다.

불행하게도, 정확한 프로그램임을 증명하는 것은 실제로는 비실용적이며 파이썬 소프트웨어와 관련이 없습니다. 사소한 프로그램일지라도 여러 페이지 분량의 증명이 필요합니다; 적당히 복잡한 프로그램에 대한 정확성의 증명은 엄청난 양일 것이며, 매일 사용하는 프로그램 (파이썬 인터프리터, XML 파서, 웹 브라우저)의 정확성은 거의 증명이 불가능할 수도 있습니다. 만약 증명을 작성하거나 만들었더라도, 그 증명이 검증된 것인지 의구심이 들 것입니다; 어쩌면 그 증명에 오류가 있을 수도 있고, 프로그램의 정확성이 증명되었다고 잘못 믿고 있을 수도 있습니다.

모듈성

함수형 프로그래밍의 실질적인 이점은 문제를 작은 조각으로 분해하도록 강제한다는 점입니다. 결과적으로 프로그램은 더욱 모듈화가 됩니다. 복잡한 변환을 수행하는 거대한 함수보다, 한 가지 작업을 수행하는 작은 함수를 명시하고 작성하기가 더 쉽습니다. 작은 함수는 읽기에도 더 쉽고 오류를 확인하기도 쉽습니다.

디버깅과 테스트 용이성

함수형 방식 프로그램은 테스트하고 디버깅하는 것이 더 쉽습니다.

일반적으로 함수가 작고 분명하게 명시되기 때문에 디버깅이 단순화됩니다. 프로그램이 동작하지 않는다면, 각 함수는 데이터가 올바른지 확인할 수 있는 접점이 됩니다. 중간 지점의 입력과 출력을 살펴보면 버그가 있는 함수를 빠르게 분간할 수 있습니다.

각 함수는 잠재적으로 단위 테스트의 대상이기 때문에 테스트가 더 쉽습니다. 함수는 테스트를 실행하기 전에 복제해야 하는 시스템 상태에 의존하지 않습니다; 올바른 입력을 만들고 결과가 예상과 일치하는지 확인만 하면 됩니다.

결합성

함수형 방식의 프로그램을 만들 때, 다양한 입력과 출력으로 여러 가지 함수를 작성하게 됩니다. 이러한 함수 중 일부는 불가피하게 특정 응용 프로그램에 특화될 수 있지만, 대체로 다양한 프로그램에서 유용하게 사용할 수 있습니다. 예를 들어 디렉터리 경로를 받아서 그 디렉터리 내의 모든 XML 파일을 반환하는 함수나, 혹은 파일명을 받아서 그 내용을 반환하는 함수는 다양한 상황에 적용할 수 있습니다.

시간이 흐르면, 여러분은 개인적인 유틸리티 라이브러리를 구성하게 될 것입니다. 보통, 새로운 구성으로 기존 함수를 배치하고 현재 작업에 특화된 몇 가지 함수만을 작성해서 새로운 프로그램을 구성하게 됩니다.

이터레이터

함수형 방식의 프로그램을 작성하는 중요한 토대가 되는 파이썬 언어의 기능을 살펴보겠습니다: 이터레이터.

이터레이터는 데이터 스트림을 나타내는 객체입니다; 이 객체는 한 번에 한 요소씩 데이터를 반환합니다. 파이썬 이터레이터는 반드시 __next__() 라는 메서드를 지원해야 합니다. 이 메서드는 인자를 취하지 않고 항상 스트림의 다음 요소를 반환합니다. 만약 스트림에 더는 요소가 없다면, __next__() 는 StopIteration 예외를 발생시켜야 합니다. 이터레이터가 유한할 필요는 없습니다; 무한한 데이터 스트림을 생성하는 이터레이터를 작성하는 것도 합리적인 방법입니다.

내장 함수 iter() 는 임의의 객체를 취하여 객체의 내용이나 요소를 반환하는 이터레이터를 반환합니다. 객체가 이터레이션을 지원하지 않으면 TypeError 를 발생시킵니다. 파이썬의 내장 데이터형 중 몇 가지가 이터레이션을 지원하는데, 가장 일반적인 것은 리스트와 딕셔너리입니다. 이터레이터를 얻을 수 있는 객체는 이터러블 이라고 불립니다.

수동으로 이터레이션 인터페이스를 실험해볼 수 있습니다:

>>> L = [1, 2, 3]
>>> it = iter(L)
>>> it
<...iterator object at ...>
>>> it.__next__()  # same as next(it)
1
>>> next(it)
2
>>> next(it)
3
>>> next(it)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration
>>>

파이썬은 여러 다른 컨텍스트에서 이터러블 객체를 기대하며, 가장 중요한 것은 for 문입니다. for X in Y 문에서 Y는 반드시 이터레이터 혹은 iter() 가 이터레이터를 생성할 수 있는 객체이어야 합니다. 다음 두 문장은 같은 의미입니다:

for i in iter(obj):
    print(i)

for i in obj:
    print(i)

이터레이터는 list() 또는 tuple() 생성자 함수를 사용하여 리스트나 튜플로 나타낼 수 있습니다:

>>> L = [1, 2, 3]
>>> iterator = iter(L)
>>> t = tuple(iterator)
>>> t
(1, 2, 3)

시퀀스 언 패킹 또한 이터레이터를 지원합니다: 이터레이터가 N개의 요소를 반환한다는 것을 알고 있다면, 그것들을 N-튜플로 언 패킹할 수 있습니다:

>>> L = [1, 2, 3]
>>> iterator = iter(L)
>>> a, b, c = iterator
>>> a, b, c
(1, 2, 3)

max() 및 min() 과 같은 내장 함수는 하나의 이터레이터 인자를 취할 수 있으며 가장 큰 혹은 가장 작은 요소를 반환합니다. "in" 과 "not in" 연산자 또한 이터레이터를 지원합니다: 이터레이터가 반환한 스트림에서 X가 발견되면 X in iterator 는 참입니다. 이터레이터가 무한하다면 명백한 문제에 부딪힙니다; max() 와 min() 는 영원히 결과를 반환하지 않으며, 요소 X가 스트림에서 나타나지 않으면 "in" 과 "not in" 연산자 역시 영원히 결과를 반환하지 않을 것입니다.

이터레이터에서는 오직 앞으로만 나아갈 수 있다는 점에 유의하세요; 이전 요소를 가져오거나, 이터레이터를 재설정하거나, 사본을 만들 방법은 없습니다. 이터레이터 객체는 선택적으로 이러한 추가 기능을 제공할 수 있지만, 이터레이터 프로토콜은 __next__() 메서드만 명시해두었습니다. 함수는 모든 이터레이터의 출력을 소비할 수 있으므로 같은 스트림에서 다른 작업을 수행해야 하는 경우 새로운 이터레이터를 만들어야 합니다.

이터레이터를 지원하는 데이터형

리스트와 튜플이 이터레이터를 어떻게 지원하는지 이미 살펴보았습니다. 실제로 문자열과 같은 파이썬 시퀀스형은 이터레이터의 생성을 자동으로 지원합니다.

iter() 를 딕셔너리에 적용하면 딕셔너리의 키를 반복하는 이터레이터를 반환합니다:

>>> m = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
...      'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
>>> for key in m:
...     print(key, m[key])
Jan 1
Feb 2
Mar 3
Apr 4
May 5
Jun 6
Jul 7
Aug 8
Sep 9
Oct 10
Nov 11
Dec 12

파이썬 3.7부터는, 딕셔너리 이터레이션 순서가 삽입 순서와 같음을 보장합니다. 이전 버전에서는, 동작이 지정되지 않았고 구현마다 다를 수 있었습니다.

iter() 를 딕셔너리에 적용하는 것은 항상 키를 반복하지만, 딕셔너리에는 다른 이터레이터를 반환하는 메서드가 있습니다. 값이나 키/값 쌍을 반복하는 경우에는 명시적으로 values() 혹은 items() 메서드를 사용하여 적절한 이터레이터를 얻을 수 있습니다.

dict() 생성자는 (키, 값) 튜플의 유한한 스트림을 반환하는 이터레이터를 받을 수 있습니다:

>>> L = [('Italy', 'Rome'), ('France', 'Paris'), ('US', 'Washington DC')]
>>> dict(iter(L))
{'Italy': 'Rome', 'France': 'Paris', 'US': 'Washington DC'}

또한 파일은 더는 새로운 줄이 없을 때까지 readline() 메서드를 호출하여 이터레이션을 지원합니다. 즉, 다음과 같이 파일의 각 행을 읽을 수 있습니다:

for line in file:
    # do something for each line
    ...

집합은 이터러블에서 내용을 가져와서 집합의 원소를 반복할 수 있습니다:

>>> S = {2, 3, 5, 7, 11, 13}
>>> for i in S:
...     print(i)
2
3
5
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제너레이터 표현식과 리스트 컴프리헨션

이터레이터의 출력에 대한 두 가지 일반적인 연산은 1) 모든 요소에 대해 어떤 연산을 수행하고, 2) 어떤 조건을 만족하는 요소의 부분 집합을 선택하는 것입니다. 예를 들어 문자열 리스트가 있으면 각 줄에서 후미 공백을 제거하거나, 주어진 부분 문자열을 포함하는 모든 문자열을 추출할 수 있습니다.

리스트 컴프리헨션과 제너레이터 표현식(줄임말: “listcomps” 및 “genexps”)은 함수형 프로그래밍 언어 하스켈(https://www.haskell.org/)에서 빌린 이러한 작업을 위한 간결한 표기법입니다. 다음 코드를 사용하여 문자열 스트림에서 모든 공백을 제거할 수 있습니다:

>>> line_list = ['  line 1\n', 'line 2  \n', ' \n', '']

>>> # Generator expression -- returns iterator
>>> stripped_iter = (line.strip() for line in line_list)

>>> # List comprehension -- returns list
>>> stripped_list = [line.strip() for line in line_list]

"if" 조건을 추가하여 특정 요소만 선택할 수도 있습니다:

>>> stripped_list = [line.strip() for line in line_list
...                  if line != ""]

리스트 컴프리헨션을 사용하면 파이썬 리스트를 얻을 수 있습니다; stripped_list 는 이터레이터가 아니라 결과 행을 담고 있는 리스트입니다. 제너레이터 표현식은 필요에 따라 값을 계산하는 이터레이터를 반환하며 모든 값을 한 번에 구체화할 필요가 없습니다. 즉, 무한 스트림이나 매우 많은 양의 데이터를 반환하는 이터레이터로 작업하는 경우 리스트 컴프리헨션은 유용하지 않습니다. 제너레이터 표현식은 이러한 상황에서 유용합니다.

제너레이터 표현식은 괄호(“()”)로 묶여 있으며 리스트 컴프리헨션은 대괄호(“[]”)로 묶여 있습니다. 제너레이터 표현식은 다음과 같은 형식입니다:

( expression for expr in sequence1
             if condition1
             for expr2 in sequence2
             if condition2
             for expr3 in sequence3
             ...
             if condition3
             for exprN in sequenceN
             if conditionN )

다시 말하면, 리스트 컴프리헨션을 위해서는 바깥쪽 괄호만 다릅니다(괄호 대신 대괄호).

생성된 출력의 요소는 expression 의 연속적인 값이 될 것입니다. if 절은 모두 선택적입니다; if 절이 존재한다면, expression 은 condition 이 참일 때만 평가되고 결과에 추가됩니다.

제너레이터 표현식은 항상 괄호 안에 작성해야 하지만 함수 호출을 알리는 괄호도 포함됩니다. 함수에 즉시 전달되는 이터레이터를 만들고 싶다면 다음과 같이 작성할 수 있습니다:

obj_total = sum(obj.count for obj in list_all_objects())

for...in 절은 반복할 시퀀스를 포함합니다. 시퀀스는 왼쪽에서 오른쪽으로 반복되며 병렬로 처리되지 않기 때문에 같은 길이일 필요는 없습니다. sequence1 의 각 요소에 대해 sequence2 는 처음부터 반복됩니다. sequence3 은 sequence1 과 sequence2 의 각각 모든 결과에 대해 반복됩니다.

다른 식으로 표현하면, 리스트 컴프리헨션 혹은 제너레이터 표현식은 다음 파이썬 코드와 같습니다:

for expr1 in sequence1:
    if not (condition1):
        continue   # Skip this element
    for expr2 in sequence2:
        if not (condition2):
            continue   # Skip this element
        ...
        for exprN in sequenceN:
            if not (conditionN):
                continue   # Skip this element

            # Output the value of
            # the expression.

이것은 여러 개의 for...in 절이 있지만 if 절이 없을 때 결과 출력의 길이가 모든 시퀀스 길이의 곱과 같음을 의미합니다. 길이가 3인 두 개의 리스트가 있는 경우 출력 목록의 길이는 9개입니다:

>>> seq1 = 'abc'
>>> seq2 = (1, 2, 3)
>>> [(x, y) for x in seq1 for y in seq2]
[('a', 1), ('a', 2), ('a', 3),
 ('b', 1), ('b', 2), ('b', 3),
 ('c', 1), ('c', 2), ('c', 3)]

파이썬 문법의 모호함을 피하고자, expression 이 튜플을 생성하고 있다면, 괄호로 묶어야 합니다. 아래의 첫 번째 리스트 컴프리헨션은 구문 오류이며, 두 번째는 올바릅니다:

# Syntax error
[x, y for x in seq1 for y in seq2]
# Correct
[(x, y) for x in seq1 for y in seq2]

제너레이터

제너레이터는 이터레이터를 작성하는 작업을 단순화하는 특별한 클래스의 함수입니다. 일반 함수는 값을 계산하여 반환하지만, 제너레이터는 값의 스트림을 반환하는 이터레이터를 반환합니다.

파이썬이나 C에서 정규 함수 호출이 어떻게 작동하는지 잘 알고 있을 것입니다. 함수를 호출하면 지역 변수가 생성되는 비공개 이름 공간이 생깁니다. 함수가 return 문에 도달하면 지역 변수가 소멸하고 그 값이 호출자에게 반환됩니다. 같은 함수를 나중에 호출하면 새로운 비공개 이름 공간과 새로운 지역 변수 집합이 만들어집니다. 그러나 지역 변수가 함수를 빠져나갈 때 버려지지 않으면 어떻게 될까요? 나중에 중단했던 곳에서 함수를 다시 시작할 수 있다면 어떨까요? 이것이 제너레이터가 제공하는 것입니다; 그들은 재개 가능한 함수라고 생각할 수 있습니다.

다음은 제너레이터 함수의 가장 간단한 예입니다:

>>> def generate_ints(N):
...    for i in range(N):
...        yield i

yield 키워드를 포함하는 함수는 제너레이터 함수입니다; 이것은 파이썬의 바이트 코드 컴파일러에 의해 감지됩니다. 결과적으로 컴파일러는 특별하게 함수를 컴파일합니다.

제너레이터 함수를 호출하면 단일 값을 반환하지 않습니다; 대신 이터레이터 프로토콜을 지원하는 제너레이터 객체를 반환합니다. yield 표현식을 실행하면 제너레이터는 return 문과 비슷하게 i 의 값을 출력합니다. yield 와 return 의 큰 차이점은 yield 에 도달하면 제너레이터의 실행 상태가 일시 중단되고 지역 변수가 보존된다는 것입니다. 제너레이터의 __next__() 메서드가 다음에 실행될 때, 함수가 다시 실행됩니다.

다음은 generate_ints() 제너레이터의 사용 예입니다:

>>> gen = generate_ints(3)
>>> gen
<generator object generate_ints at ...>
>>> next(gen)
0
>>> next(gen)
1
>>> next(gen)
2
>>> next(gen)
Traceback (most recent call last):
  File "stdin", line 1, in <module>
  File "stdin", line 2, in generate_ints
StopIteration

여러분은 똑같이 for i in generate_ints(5) 또는 a, b, c = generate_ints(3) 라고 쓸 수 있습니다.

제너레이터 함수 내에서, return value 는 __next__() 메서드에서 StopIteration(value) 를 발생시킵니다. 이런 일이 발생하거나 함수의 맨 아래에 도달하면 값의 행렬이 끝나고 제너레이터는 더는 값을 산출할 수 없습니다.

직접 클래스를 작성하고 제너레이터의 모든 지역 변수를 인스턴스 변수로 저장하여 제너레이터의 효과를 수동으로 얻을 수 있습니다. 예를 들어, 정수 리스트를 반환하는 것은 self.count 를 0으로 설정하고 __next__() 메서드로 self.count 를 증가시켜 반환하는 식으로 수행할 수 있습니다. 그러나, 다소 복잡한 제너레이터의 경우에는 해당 클래스를 작성하는 것이 훨씬 더 복잡할 수 있습니다.

파이썬의 라이브러리인 Lib/test/test_generators.py [https://github.com/python/cpython/tree/main/Lib/test/test_generators.py] 에 포함된 테스트 묶음에는 더 많은 흥미로운 예제들이 있습니다. 제너레이터를 재귀적으로 사용하여 트리를 중위 순회하는 것을 구현하는 하나의 제너레이터가 있습니다.

# A recursive generator that generates Tree leaves in in-order.
def inorder(t):
    if t:
        for x in inorder(t.left):
            yield x

        yield t.label

        for x in inorder(t.right):
            yield x

test_generators.py 의 다른 두 가지 예는, N-여왕 문제(NxN 체스판에 서로 다른 왕비를 위협할 수 없도록 N개의 왕비를 배치하는 문제)와 기사의 여행(기사가 NxN 체스판의 모든 칸을 정확히 한 번씩 갈 수 있도록 하는 방법을 찾는 문제)입니다.

제너레이터에 값 전달하기

파이썬 2.4 및 그 이전 버전에서 제너레이터는 출력만 생성했습니다. 제너레이터의 코드가 이터레이터를 만들기 위해 호출된 후에는 그 실행이 다시 시작될 때 함수에 새로운 정보를 전달할 방법이 없었습니다. 제너레이터가 전역 변수를 보거나 호출자가 수정할 수 있는 변경 가능한 객체를 전달함으로써 이 기능을 해킹할 수 있지만, 이러한 접근법은 지저분한 방식입니다.

파이썬 2.5에서는 제너레이터에 값을 전달하는 간단한 방법이 있습니다. yield 는 표현식이 되어 변수에 대입하거나 다른 식으로 조작할 수 있는 값을 반환합니다:

val = (yield i)

위 예제처럼 반환 값으로 무엇인가를 할 때 yield 표현식 주위에 항상 괄호를 넣는 것이 좋습니다. 괄호는 항상 필요한 것은 아니지만 필요한 시점을 기억하지 않고 항상 추가하기가 더 쉽습니다.

(PEP 342 [https://peps.python.org/pep-0342/] 는 정확한 규칙을 설명합니다. 이것은 대입의 오른쪽에 있는 최상위 표현식에서 발생하는 경우를 제외하고 항상 yield 표현식을 괄호로 묶어야 한다는 것입니다. val = yield i 라고 쓸 수도 있지만, val = (yield i) + 12 처럼 연산이 있을 때는 괄호를 써야합니다.)

값은 send(value) 메서드를 호출하여 제너레이터로 보내집니다. 이 메서드는 제너레이터의 코드를 다시 시작하고 yield 표현식은 지정된 값을 반환합니다. 만약 정규 __next__() 메서드가 호출되면 yield 는 None 을 반환합니다.

다음은 1씩 증가하며 내부 카운터값을 변경할 수 있는 간단한 카운터입니다.

def counter(maximum):
    i = 0
    while i < maximum:
        val = (yield i)
        # If value provided, change counter
        if val is not None:
            i = val
        else:
            i += 1

다음은 카운터 변경의 예시입니다:

>>> it = counter(10)
>>> next(it)
0
>>> next(it)
1
>>> it.send(8)
8
>>> next(it)
9
>>> next(it)
Traceback (most recent call last):
  File "t.py", line 15, in <module>
    it.next()
StopIteration

yield 가 종종 None 을 반환할 것이므로, 항상 이 경우를 확인해야 합니다. send() 메서드가 제너레이터 함수를 다시 시작하는데 사용되는 유일한 메서드가 아니라면, 표현식의 결괏값을 확인없이 사용하지 마세요.

send() 외에도 제너레이터에 대한 두 가지 다른 메서드가 있습니다:

throw(value) is used to raise an exception inside the generator; the exception is raised by the yield expression where the generator’s execution is paused.

close() 는 생성자 내에서 GeneratorExit 예외를 발생시켜 이터레이션을 종료합니다. 이 예외가 발생하면 제너레이터의 코드는 GeneratorExit 또는 StopIteration 을 발생시켜야 합니다; 예외를 받고도 다른 작업을 하는 것은 금지되어 있으며 RuntimeError 를 촉발합니다. close() 는 제너레이터가 가비지로 수거될 때 파이썬의 가비지 수거기에 의해 호출될 것입니다.

GeneratorExit 이 발생할 때 정리 작업을 위한 코드를 실행해야 한다면 GeneratorExit 를 잡는 대신 try: ... finally: 를 사용하는 것이 좋습니다.

이러한 변화의 누적 효과는 제너레이터를 일방적인 정보 생산자에서 생산자와 소비자 모두로 전환하는 것입니다.

제너레이터는 코루틴 이 되어 더 일반적인 형태의 서브루틴이 됩니다. 서브루틴은 한 지점에서 시작되고 다른 한 지점(함수의 맨 위와 return 문)에서 빠져나옵니다. 그러나 여러 다른 지점에서 코루틴을 시작하고 빠져나오고 다시 시작할 수 있습니다(yield 문).

내장 함수

이터레이터에서 자주 사용되는 내장 함수를 자세히 살펴보겠습니다.

파이썬의 두 가지 내장 함수인 map() 와 filter() 는 제너레이터 표현식의 기능을 복제합니다:

map(f, iterA, iterB, ...) 은 다음과 같은 시퀀스에 대한 이터레이터를 반환합니다.

f(iterA[0], iterB[0]), f(iterA[1], iterB[1]), f(iterA[2], iterB[2]), ....

>>> def upper(s):
...     return s.upper()

>>> list(map(upper, ['sentence', 'fragment']))
['SENTENCE', 'FRAGMENT']
>>> [upper(s) for s in ['sentence', 'fragment']]
['SENTENCE', 'FRAGMENT']

물론 리스트 컴프리헨션으로 같은 효과를 얻을 수 있습니다.

filter(predicate, iter) 는 특정 조건을 만족하는 모든 시퀀스 요소에 대한 이터레이터를 반환하며, 마찬가지로 리스트 컴프리헨션에 의해 복제됩니다. predicate 는 어떤 조건의 진릿값을 반환하는 함수입니다; filter() 와 함께 사용하는 경우, predicate는 단일 값을 받아들여야 합니다.

>>> def is_even(x):
...     return (x % 2) == 0

>>> list(filter(is_even, range(10)))
[0, 2, 4, 6, 8]

또한 이것은 리스트 컴프리헨션으로 작성될 수 있습니다:

>>> list(x for x in range(10) if is_even(x))
[0, 2, 4, 6, 8]

enumerate(iter, start=0) 는 카운트(start 부터)와 각 요소를 포함하는 2-튜플을 반환하는 이터러블의 요소를 계산합니다.

>>> for item in enumerate(['subject', 'verb', 'object']):
...     print(item)
(0, 'subject')
(1, 'verb')
(2, 'object')

enumerate() 는 리스트를 반복하고 특정 조건이 충족되는 인덱스를 기록할 때 자주 사용됩니다:

f = open('data.txt', 'r')
for i, line in enumerate(f):
    if line.strip() == '':
        print('Blank line at line #%i' % i)

sorted(iterable, key=None, reverse=False) 는 이터러블의 모든 요소를 리스트로 모으고, 리스트를 정렬하고, 정렬된 결과를 반환합니다. key 와 reverse 인자는 생성된 리스트의 sort() 메서드로 전달됩니다.

>>> import random
>>> # Generate 8 random numbers between [0, 10000)
>>> rand_list = random.sample(range(10000), 8)
>>> rand_list
[769, 7953, 9828, 6431, 8442, 9878, 6213, 2207]
>>> sorted(rand_list)
[769, 2207, 6213, 6431, 7953, 8442, 9828, 9878]
>>> sorted(rand_list, reverse=True)
[9878, 9828, 8442, 7953, 6431, 6213, 2207, 769]

(정렬에 대한 자세한 설명은 Sorting Techniques 를 참고하세요.)

any(iter) 및 all(iter) 내장 함수는 이터러블의 진릿값을 봅니다. any() 는 이터러블의 어떤 요소가 참이면 True 를 반환하고, all() 은 모든 요소가 참이면 True 를 반환합니다:

>>> any([0, 1, 0])
True
>>> any([0, 0, 0])
False
>>> any([1, 1, 1])
True
>>> all([0, 1, 0])
False
>>> all([0, 0, 0])
False
>>> all([1, 1, 1])
True

zip(iterA, iterB, ...) 은 각 이터러블에서 하나의 요소를 취하여 튜플로 반환합니다:

zip(['a', 'b', 'c'], (1, 2, 3)) =>
  ('a', 1), ('b', 2), ('c', 3)

이 함수는 결과를 반환하기 전에 메모리 내의 리스트를 구성하거나 모든 입력 이터레이터를 처리하지 않습니다; 대신 튜플은 요청된 경우에만 생성하여 반환합니다. (이 동작의 전문 용어는 느긋한 평가 [https://en.wikipedia.org/wiki/Lazy_evaluation] 입니다.)

이 이터레이터는 모두 같은 길이의 이터러블과 함께 사용하기 위한 것입니다. 이터러블의 길이가 다른 경우 결과 스트림은 가장 짧은 이터러블과 같은 길이가 됩니다.

zip(['a', 'b'], (1, 2, 3)) =>
  ('a', 1), ('b', 2)

더 긴 이터레이터에서 나머지 요소는 버려질 수 있기 때문에 이런 방식은 피해야 합니다. 즉, 삭제된 요소를 건너뛸 위험이 있으므로 이터레이터를 계속 사용할 수 없습니다.

itertools 모듈

The itertools module contains a number of commonly used iterators as well as functions for combining several iterators. This section will introduce the module’s contents by showing small examples.

모듈의 기능은 몇 가지 광범위한 클래스로 분류됩니다:

기존 이터레이터를 기반으로 새로운 이터레이터를 만드는 함수.

이터레이터의 요소를 함수 인자로 처리하는 함수.

이터레이터의 출력 부분을 선택하는 함수.

이터레이터의 출력을 분류하는 함수.

새로운 이터레이터 만들기

itertools.count(start, step) 는 균등하게 간격을 둔 값들의 무한한 스트림을 반환합니다. 선택적으로 기본값이 0인 시작 번호와 기본값이 1인 숫자 사이의 간격을 제공할 수 있습니다:

itertools.count() =>
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...
itertools.count(10) =>
  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ...
itertools.count(10, 5) =>
  10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ...

itertools.cycle(iter) 은 제공된 이터러블의 내용 사본을 저장하고 처음부터 마지막까지 요소를 반환하는 새로운 이터레이터를 반환합니다. 새로운 이터레이터는 이러한 요소를 무한히 반복합니다.

itertools.cycle([1, 2, 3, 4, 5]) =>
  1, 2, 3, 4, 5, 1, 2, 3, 4, 5, ...

itertools.repeat(elem, [n]) 는 제공된 요소를 n 번 반환하거나, n 이 제공되지 않으면 끝없이 요소를 반환합니다.

itertools.repeat('abc') =>
  abc, abc, abc, abc, abc, abc, abc, abc, abc, abc, ...
itertools.repeat('abc', 5) =>
  abc, abc, abc, abc, abc

itertools.chain(iterA, iterB, ...) 은 임의의 수의 이터러블을 입력으로 취하여, 첫 번째 이터러블의 모든 요소를 반환한 다음 두 번째 요소의 모든 요소를 반환하고, 모든 이터러블이 다 소모될 때까지 이 동작을 반복합니다.

itertools.chain(['a', 'b', 'c'], (1, 2, 3)) =>
  a, b, c, 1, 2, 3

itertools.islice(iter, [start], stop, [step]) 는 이터레이터의 조각 스트림을 반환합니다. 단일 stop 인자를 사용하면 처음 stop개 요소가 반환됩니다. 시작 인덱스를 지정하면 stop-start 요소가 생기고, step 에 값을 지정하면 요소는 그에 따라 생략됩니다. 파이썬의 문자열 및 리스트 슬라이싱과 달리, start, stop, step 에 음수값을 사용할 수 없습니다.

itertools.islice(range(10), 8) =>
  0, 1, 2, 3, 4, 5, 6, 7
itertools.islice(range(10), 2, 8) =>
  2, 3, 4, 5, 6, 7
itertools.islice(range(10), 2, 8, 2) =>
  2, 4, 6

itertools.tee(iter, [n]) 는 이터레이터를 복제합니다; 원본 이터레이터의 내용을 모두 반환하는 n 개의 독립적인 이터레이터를 반환합니다. n 에 대한 값을 제공하지 않으면 기본값은 2입니다. 이터레이터를 복제하려면 원본 이터레이터의 일부 내용을 저장해야 하므로 이터레이터가 크고 새로운 이터레이터 중 하나가 다른 것보다 많이 소비된다면 이것은 상당한 메모리를 소비할 수 있습니다.

itertools.tee( itertools.count() ) =>
   iterA, iterB

where iterA ->
   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...

and   iterB ->
   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...

요소에 대한 함수 호출

operator 모듈은 파이썬의 연산자에 대응하는 함수 집합을 포함합니다. 예를 들어 operator.add(a, b) (두 개의 값을 더하기), operator.ne(a, b) (a != b 와 동일) 및 operator.attrgetter('id') (.id 어트리뷰트를 가져오는 콜러블을 반환)와 같은 함수가 있습니다.

itertools.starmap(func, iter) 은 이터러블이 튜플의 스트림을 반환할 것이라고 가정하고, 이 튜플을 인자로 사용하여 func 를 호출합니다:

itertools.starmap(os.path.join,
                  [('/bin', 'python'), ('/usr', 'bin', 'java'),
                   ('/usr', 'bin', 'perl'), ('/usr', 'bin', 'ruby')])
=>
  /bin/python, /usr/bin/java, /usr/bin/perl, /usr/bin/ruby

요소 선택하기

또 다른 함수 모음은 서술자에 기초하여 이터러블 요소의 부분 집합을 선택합니다.

itertools.filterfalse(predicate, iter) 는 filter() 의 반대이며, predicate가 거짓을 반환하는 모든 요소를 반환합니다:

itertools.filterfalse(is_even, itertools.count()) =>
  1, 3, 5, 7, 9, 11, 13, 15, ...

itertools.takewhile(predicate, iter) 은 predicate가 참을 반환하는 한, 요소를 반환합니다. predicate가 거짓을 반환하면 이터레이터는 결과의 종료를 알립니다.

def less_than_10(x):
    return x < 10

itertools.takewhile(less_than_10, itertools.count()) =>
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9

itertools.takewhile(is_even, itertools.count()) =>
  0

itertools.dropwhile(predicate, iter) 은 predicate가 참을 반환하는 동안 요소를 버리고, 나머지 이터러블의 결과를 반환합니다.

itertools.dropwhile(less_than_10, itertools.count()) =>
  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ...

itertools.dropwhile(is_even, itertools.count()) =>
  1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...

itertools.compress(data, selectors) 는 두 개의 이터레이터를 취하고 selectors 의 해당 요소가 참인 data 의 요소만을 반환하고, 한쪽이 고갈될 때마다 중단합니다:

itertools.compress([1, 2, 3, 4, 5], [True, True, False, False, True]) =>
   1, 2, 5

조합 함수

itertools.combinations(iterable, r) 는 iterable 에 포함된 모든 요소의 가능한 r-튜플 조합을 제공하는 이터레이터를 반환합니다.

itertools.combinations([1, 2, 3, 4, 5], 2) =>
  (1, 2), (1, 3), (1, 4), (1, 5),
  (2, 3), (2, 4), (2, 5),
  (3, 4), (3, 5),
  (4, 5)

itertools.combinations([1, 2, 3, 4, 5], 3) =>
  (1, 2, 3), (1, 2, 4), (1, 2, 5), (1, 3, 4), (1, 3, 5), (1, 4, 5),
  (2, 3, 4), (2, 3, 5), (2, 4, 5),
  (3, 4, 5)

각 튜플 내의 원소들은 iterable 이 반환한 것과 같은 순서로 유지됩니다. 예를 들어 위의 예시에서 숫자 1은 항상 2, 3, 4 또는 5 앞에 옵니다. 비슷한 함수인 itertools.permutations(iterable, r=None) 은 제약 조건을 제거하여 길이 r 의 가능한 모든 순열을 반환합니다:

itertools.permutations([1, 2, 3, 4, 5], 2) =>
  (1, 2), (1, 3), (1, 4), (1, 5),
  (2, 1), (2, 3), (2, 4), (2, 5),
  (3, 1), (3, 2), (3, 4), (3, 5),
  (4, 1), (4, 2), (4, 3), (4, 5),
  (5, 1), (5, 2), (5, 3), (5, 4)

itertools.permutations([1, 2, 3, 4, 5]) =>
  (1, 2, 3, 4, 5), (1, 2, 3, 5, 4), (1, 2, 4, 3, 5),
  ...
  (5, 4, 3, 2, 1)

r 에 값을 지정하지 않으면 이터러블의 길이가 사용됩니다. 즉, 모든 요소가 치환됩니다.

이 함수는 위치별로 가능한 모든 조합을 생성하며 iterable 의 내용이 고유해야 할 필요는 없습니다:

itertools.permutations('aba', 3) =>
  ('a', 'b', 'a'), ('a', 'a', 'b'), ('b', 'a', 'a'),
  ('b', 'a', 'a'), ('a', 'a', 'b'), ('a', 'b', 'a')

같은 튜플 ('a', 'a', 'b') 가 두 번 발생하지만, 두 개의 ‘a’ 문자열은 다른 위치에서 왔습니다.

itertools.combinations_with_replacement(iterable, r) 함수는 다른 제약을 완화합니다: 요소는 단일 튜플 내에서 반복될 수 있습니다. 개념적으로 요소는 각 튜플의 첫 번째 위치에 대해 선택되고 두 번째 요소가 선택되기 전에 대체됩니다.

itertools.combinations_with_replacement([1, 2, 3, 4, 5], 2) =>
  (1, 1), (1, 2), (1, 3), (1, 4), (1, 5),
  (2, 2), (2, 3), (2, 4), (2, 5),
  (3, 3), (3, 4), (3, 5),
  (4, 4), (4, 5),
  (5, 5)

요소 분류

마지막으로 소개할 itertools.groupby(iter, key_func=None) 함수는 가장 복잡합니다. key_func(elem) 는 이터러블에 의해 반환된 각 요소에 대한 키값을 계산할 수 있는 함수입니다. 키 함수를 제공하지 않으면 키는 단순히 각 요소 자체입니다.

groupby() 는 이터러블 내부에서 키값이 같은 연속된 모든 요소를 수집하여 키값과 해당 키를 가진 요소의 이터러블을 포함하는 2-튜플의 스트림을 반환합니다.

city_list = [('Decatur', 'AL'), ('Huntsville', 'AL'), ('Selma', 'AL'),
             ('Anchorage', 'AK'), ('Nome', 'AK'),
             ('Flagstaff', 'AZ'), ('Phoenix', 'AZ'), ('Tucson', 'AZ'),
             ...
            ]

def get_state(city_state):
    return city_state[1]

itertools.groupby(city_list, get_state) =>
  ('AL', iterator-1),
  ('AK', iterator-2),
  ('AZ', iterator-3), ...

where
iterator-1 =>
  ('Decatur', 'AL'), ('Huntsville', 'AL'), ('Selma', 'AL')
iterator-2 =>
  ('Anchorage', 'AK'), ('Nome', 'AK')
iterator-3 =>
  ('Flagstaff', 'AZ'), ('Phoenix', 'AZ'), ('Tucson', 'AZ')

groupby() 는 이터러블 내부의 내용이 키에 따라 이미 정렬되었다고 가정합니다. 반환된 이터레이터 역시 이터러블 내부를 사용하므로 이터레이터-2와 해당 키를 요청하기 전에 이터레이터-1의 결과를 소진해야 합니다.

functools 모듈

The functools module contains some higher-order functions. A higher-order function takes one or more functions as input and returns a new function. The most useful tool in this module is the functools.partial() function.

함수형 방식으로 작성된 프로그램의 경우, 일부 매개 변수가 채워진 기존 함수의 변형이 필요한 경우가 있습니다. 파이썬 함수 f(a, b, c) 를 고려해보세요; 파이썬 함수인 f(1, b, c) 에 해당하는 새로운 함수 g(b, c) 를 만들 수 있습니다; 이를 “부분적 함수 적용” 이라고 합니다.

partial() 의 생성자는 (function, arg1, arg2, ..., kwarg1=value1, kwarg2=value2) 와 같은 인자를 취합니다. 결과 객체는 콜러블이므로, 채워진 인자로 function 을 실행하기 위해서는 결과 객체를 호출하면 됩니다.

작지만 현실적인 예가 있습니다:

import functools

def log(message, subsystem):
    """Write the contents of 'message' to the specified subsystem."""
    print('%s: %s' % (subsystem, message))
    ...

server_log = functools.partial(log, subsystem='server')
server_log('Unable to open socket')

functools.reduce(func, iter, [initial_value]) 는 모든 이터러블 요소에 대해 누적 연산을 수행하므로 무한 이터러블에 적용할 수 없습니다. func 는 두 요소를 사용하여 하나의 값을 반환하는 함수이어야 합니다. functools.reduce() 는 이터레이터가 반환한 처음 두 요소 A와 B를 취해 func(A, B) 를 계산합니다. 그다음 세 번째 요소인 C를 취해 func(func(A, B), C) 를 계산하고, 이 결과를 반환된 네 번째 요소와 결합해 이터러블이 소진될 때까지 계속합니다. 이터러블이 전혀 값을 반환하지 않으면 TypeError 예외가 발생합니다. 초기값이 제공되면 시작점으로 사용되며 func(initial_value, A) 가 첫 번째로 계산됩니다.

>>> import operator, functools
>>> functools.reduce(operator.concat, ['A', 'BB', 'C'])
'ABBC'
>>> functools.reduce(operator.concat, [])
Traceback (most recent call last):
  ...
TypeError: reduce() of empty sequence with no initial value
>>> functools.reduce(operator.mul, [1, 2, 3], 1)
6
>>> functools.reduce(operator.mul, [], 1)
1

operator.add() 를 functools.reduce() 와 함께 사용하면 이터러블의 모든 요소를 합합니다. 이 경우는 매우 일반적이어서 이를 계산하기 위해 sum() 이라는 특수 내장 함수가 제공됩니다:

>>> import functools, operator
>>> functools.reduce(operator.add, [1, 2, 3, 4], 0)
10
>>> sum([1, 2, 3, 4])
10
>>> sum([])
0

그렇지만 functools.reduce() 를 사용하는 많은 경우에 명백하게 for 루프만 작성하는 것이 더 명확할 수 있습니다:

import functools
# Instead of:
product = functools.reduce(operator.mul, [1, 2, 3], 1)

# You can write:
product = 1
for i in [1, 2, 3]:
    product *= i

A related function is itertools.accumulate(iterable, func=operator.add). It performs the same calculation, but instead of returning only the final result, accumulate() returns an iterator that also yields each partial result:

itertools.accumulate([1, 2, 3, 4, 5]) =>
  1, 3, 6, 10, 15

itertools.accumulate([1, 2, 3, 4, 5], operator.mul) =>
  1, 2, 6, 24, 120

operator 모듈

operator 모듈은 이전에 언급되었습니다. 여기에는 파이썬 연산자에 해당하는 함수 집합이 포함되어 있습니다. 단일 연산을 수행하는 사소한 함수를 작성하지 않아도 되므로 이러한 함수는 함수형 방식 코드에서 유용합니다.

이 모듈의 몇몇 함수는 다음과 같습니다:

수학 연산: add(), sub(), mul(), floordiv(), abs(), …

논리 연산: not_(), truth().

비트 연산: and_(), or_(), invert().

비교: eq(), ne(), lt(), le(), gt(), ge().

객체 아이덴티티: is_(), is_not().

전체 목록은 연산자 모듈의 문서를 참고하세요.

작은 함수와 람다 표현식

함수형 방식의 프로그램을 작성할 때, 서술자로 동작하거나 어떤 식으로든 요소를 결합하는 작은 함수가 필요할 것입니다.

파이썬 내장 함수나 적당한 모듈 함수가 있다면, 새로운 함수를 정의할 필요가 전혀 없습니다:

stripped_lines = [line.strip() for line in lines]
existing_files = filter(os.path.exists, file_list)

필요한 기능이 없다면 작성해야 합니다. 작은 함수를 작성하는 한 가지 방법은 lambda 표현식을 사용하는 것입니다. lambda 는 여러 매개 변수와 이들 매개 변수를 결합하는 표현식을 취해 표현식의 값을 반환하는 익명의 함수를 만듭니다:

adder = lambda x, y: x+y

print_assign = lambda name, value: name + '=' + str(value)

다른 방법은 def 문을 사용하고 일반적인 방식으로 함수를 정의하는 것입니다:

def adder(x, y):
    return x + y

def print_assign(name, value):
    return name + '=' + str(value)

어떤 대안이 바람직할까요? 이것은 스타일에 대한 질문입니다; 필자가 평소에 사용하는 방법은 lambda 사용을 피하는 것입니다.

필자가 선호하는 방식에 대한 이유 중 하나는 lambda 가 정의할 수 있는 함수가 상당히 제한적이기 때문입니다. 결과는 단일 표현식으로 계산할 수 있어야 합니다. 즉, if... elif... else 비교 또는 try... except 문을 가질 수 없습니다. lambda 문에서 너무 많은 것을 하려고 하면, 읽기 어려운 복잡한 표현으로 끝날 것입니다. 다음 코드가 무엇을 하는지 빠르게 알아보세요.

import functools
total = functools.reduce(lambda a, b: (0, a[1] + b[1]), items)[1]

여러분은 이해할 수 있지만, 어떻게 동작하는지 이해하기 위해 표현식을 풀어내는 데 시간이 걸립니다. 짧게 중첩된 def 문을 사용하면 좀 더 나은 것을 만들 수 있습니다:

import functools
def combine(a, b):
    return 0, a[1] + b[1]

total = functools.reduce(combine, items)[1]

그러나 단순히 for 루프를 사용했다면 가장 좋았을 것입니다:

total = 0
for a, b in items:
    total += b

혹은 sum() 내장 함수와 제너레이터 표현식이었어도 좋았을 것입니다:

total = sum(b for a, b in items)

functools.reduce() 를 사용하는 많은 경우, for 루프로 작성했을 때 더 명확합니다.

Fredrik Lundh는 한때 lambda 사용법의 리팩토링을 위해 다음과 같은 규칙 집합을 제안했습니다:

람다 함수를 작성하세요.

람다가 하는 일에 관해 설명하는 글을 쓰세요.

잠깐 설명을 검토하고 설명의 본질을 포착하는 이름을 생각해보세요.

해당 이름을 사용하여 람다를 def 문으로 변환합니다.

설명을 삭제하세요.

필자는 이 규칙을 정말 좋아하지만, 여러분은 이렇게 람다가 없는 방식이 더 나은지에 대해 동의하지 않을 수 있습니다.

개정내역 및 감사의 글

필자는 이 글의 다양한 초안을 제안하고 수정하고 도와준 다음 사람들에게 감사하고 싶습니다: Ian Bicking, Nick Coghlan, Nick Efford, Raymond Hettinger, Jim Jewett, Mike Krell, Leandro Lameiro, Jussi Salmela, Collin Winter, Blake Winton.

버전 0.1: 2006년 6월 30일 게시.

버전 0.11: 2006년 7월 1일 게시. 오타 수정.

버전 0.2: 2006년 7월 10일 게시. 제너레이터 표현식과 리스트 컴프리헨션 섹션을 하나로 통합. 오타 수정.

버전 0.21: 튜터 메일링 리스트에서 추천된 참고 문헌을 추가.

버전 0.30: Collin Winter가 작성한 functional 모듈에 대한 섹션 추가; 연산자 모듈에 대한 짧은 섹션 추가; 몇 가지 다른 편집.

참고 문헌

일반

Structure and Interpretation of Computer Programs, by Harold Abelson and Gerald Jay Sussman with Julie Sussman. The book can be found at https://mitpress.mit.edu/sicp. In this classic textbook of computer science, chapters 2 and 3 discuss the use of sequences and streams to organize the data flow inside a program. The book uses Scheme for its examples, but many of the design approaches described in these chapters are applicable to functional-style Python code.

https://www.defmacro.org/ramblings/fp.html: A general introduction to functional programming that uses Java examples and has a lengthy historical introduction.

https://en.wikipedia.org/wiki/Functional_programming: 함수형 프로그래밍을 설명하는 일반 위키피디아 항목.

https://en.wikipedia.org/wiki/Coroutine: 코루틴에 대한 항목.

https://en.wikipedia.org/wiki/Partial_application: Entry for the concept of partial function application.

https://en.wikipedia.org/wiki/Currying: 커링 개념에 대한 항목.

파이썬 특정

https://gnosis.cx/TPiP/: The first chapter of David Mertz’s book Text Processing in Python discusses functional programming for text processing, in the section titled “Utilizing Higher-Order Functions in Text Processing”.

Mertz는 또한 IBM의 DeveloperWorks 사이트에서 함수형 프로그래밍 기사 시리즈 3부작을 작성했습니다; part 1 [https://developer.ibm.com/articles/l-prog/], part 2 [https://developer.ibm.com/tutorials/l-prog2/], part 3 [https://developer.ibm.com/tutorials/l-prog3/],

파이썬 설명서

itertools 모듈에 대한 설명서

functools 모듈에 대한 설명서

operator 모듈에 대한 설명서

PEP 289 [https://peps.python.org/pep-0289/]: “제너레이터 표현식”

PEP 342 [https://peps.python.org/pep-0342/]: “개선된 제너레이터를 통한 코루틴” 은 파이썬 2.5의 새로운 제너레이터 기능을 설명합니다.

로깅 HOWTO

저자:

Vinay Sajip <vinay_sajip at red-dove dot com>

This page contains tutorial information. For links to reference information and a logging cookbook, please see Other resources.

기초 로깅 자습서

로깅은 어떤 소프트웨어가 실행될 때 발생하는 이벤트를 추적하는 수단입니다. 소프트웨어 개발자는 코드에 로깅 호출을 추가하여 특정 이벤트가 발생했음을 나타냅니다. 이벤트는 선택적으로 가변 데이터 (즉, 이벤트 발생마다 잠재적으로 다른 데이터)를 포함할 수 있는 설명 메시지로 기술됩니다. 이벤트는 또한 개발자가 이벤트에 부여한 중요도를 가지고 있습니다; 중요도는 수준(level) 또는 심각도(severity) 라고도 부를 수 있습니다.

로깅을 사용할 때

You can access logging functionality by creating a logger via logger = getLogger(__name__), and then calling the logger’s debug(), info(), warning(), error() and critical() methods. To determine when to use logging, and to see which logger methods to use when, see the table below. It states, for each of a set of common tasks, the best tool to use for that task.

수행하려는 작업

작업을 위한 최상의 도구

명령행 스크립트 또는 프로그램의 일반적인 사용을 위한 콘솔 출력 표시

print()

프로그램의 정상 작동 중에 발생하는 이벤트 보고 (가령 상태 모니터링이나 결함 조사)

A logger’s info() (or debug() method for very detailed output for diagnostic purposes)

특정 실행시간 이벤트와 관련하여 경고를 발행

라이브러리 코드에서 warnings.warn(): 문제를 피할 수 있고 경고를 제거하기 위해 클라이언트 응용 프로그램이 수정되어야 하는 경우

A logger’s warning() method if there is nothing the client application can do about the situation, but the event should still be noted

특정 실행시간 이벤트와 관련하여 에러를 보고

예외를 일으킵니다

예외를 발생시키지 않고 에러의 억제를 보고 (가령 장기 실행 서버 프로세스의 에러 처리기)

A logger’s error(), exception() or critical() method as appropriate for the specific error and application domain

The logger methods are named after the level or severity of the events they are used to track. The standard levels and their applicability are described below (in increasing order of severity):

수준

사용할 때

DEBUG

상세한 정보. 보통 문제를 진단할 때만 필요합니다.

INFO

예상대로 작동하는지에 대한 확인.

WARNING

예상치 못한 일이 발생했거나 가까운 미래에 발생할 문제(예를 들어 ‘디스크 공간 부족’)에 대한 표시. 소프트웨어는 여전히 예상대로 작동합니다.

ERROR

더욱 심각한 문제로 인해, 소프트웨어가 일부 기능을 수행하지 못했습니다.

CRITICAL

심각한 에러. 프로그램 자체가 계속 실행되지 않을 수 있음을 나타냅니다.

The default level is WARNING, which means that only events of this severity and higher will be tracked, unless the logging package is configured to do otherwise.

추적되는 이벤트는 여러 방식으로 처리될 수 있습니다. 추적된 이벤트를 처리하는 가장 간단한 방법은 콘솔에 인쇄하는 것입니다. 또 다른 일반적인 방법은 디스크 파일에 기록하는 것입니다.

간단한 예

아주 간단한 예는 이렇습니다:

import logging
logging.warning('Watch out!')  # will print a message to the console
logging.info('I told you so')  # will not print anything

이 줄들을 스크립트에 입력하고 실행하면:

WARNING:root:Watch out!

printed out on the console. The INFO message doesn’t appear because the default level is WARNING. The printed message includes the indication of the level and the description of the event provided in the logging call, i.e. ‘Watch out!’. The actual output can be formatted quite flexibly if you need that; formatting options will also be explained later.

Notice that in this example, we use functions directly on the logging module, like logging.debug, rather than creating a logger and calling functions on it. These functions operation on the root logger, but can be useful as they will call basicConfig() for you if it has not been called yet, like in this example. In larger programs you’ll usually want to control the logging configuration explicitly however - so for that reason as well as others, it’s better to create loggers and call their methods.

파일에 로깅 하기

A very common situation is that of recording logging events in a file, so let’s look at that next. Be sure to try the following in a newly started Python interpreter, and don’t just continue from the session described above:

import logging
logger = logging.getLogger(__name__)
logging.basicConfig(filename='example.log', encoding='utf-8', level=logging.DEBUG)
logger.debug('This message should go to the log file')
logger.info('So should this')
logger.warning('And this, too')
logger.error('And non-ASCII stuff, too, like Øresund and Malmö')

버전 3.9에서 변경: encoding 인자가 추가되었습니다. 이전 파이썬 버전에서, 또는 지정되지 않으면, 사용된 인코딩은 open()에서 사용되는 기본값입니다. 위의 예제에는 표시되지 않았지만, 이제 errors 인자를 전달하여 인코딩 에러 처리 방법을 결정할 수 있습니다. 사용 가능한 값과 기본값은, open() 설명서를 참조하십시오.

이제 파일을 열고 내용을 살펴본다면, 로그 메시지를 찾을 수 있습니다:

DEBUG:__main__:This message should go to the log file
INFO:__main__:So should this
WARNING:__main__:And this, too
ERROR:__main__:And non-ASCII stuff, too, like Øresund and Malmö

이 예제는 추적 임곗값 역할을 하는 로깅 수준을 설정하는 방법도 보여줍니다. 이 경우 임곗값을 DEBUG 로 설정했기 때문에 모든 메시지가 출력되었습니다.

다음과 같은 방식으로 명령행 옵션에서 로깅 수준을 설정하려고 하고:

--log=INFO

어떤 변수 loglevel 에 --log 로 전달된 매개 변수의 값이 들어있다면, 이런 방법으로:

getattr(logging, loglevel.upper())

level 인자를 통해 basicConfig() 에게 전달할 값을 얻습니다. 아마 다음 예제에서와같이, 사용자 입력 값을 오류 검사 하고 싶을 겁니다:

# assuming loglevel is bound to the string value obtained from the
# command line argument. Convert to upper case to allow the user to
# specify --log=DEBUG or --log=debug
numeric_level = getattr(logging, loglevel.upper(), None)
if not isinstance(numeric_level, int):
    raise ValueError('Invalid log level: %s' % loglevel)
logging.basicConfig(level=numeric_level, ...)

The call to basicConfig() should come before any calls to a logger’s methods such as debug(), info(), etc. Otherwise, that logging event may not be handled in the desired manner.

위의 스크립트를 여러 번 실행하면, 후속 실행의 메시지가 example.log 파일에 추가됩니다. 이전 실행의 메시지를 기억하지 않고, 각 실행이 새로 시작하게 하려면, 위 예제에서 호출이 filemode 인자를 지정하도록 다음과 같이 변경할 수 있습니다:

logging.basicConfig(filename='example.log', filemode='w', level=logging.DEBUG)

출력은 이전과 같지만, 더는 로그 파일에 덧붙여지지 않으므로 이전 실행의 메시지는 손실됩니다.

변수 데이터 로깅

변수 데이터를 기록하려면, 이벤트 설명 메시지에 포맷 문자열을 사용하고 변수 데이터를 인자로 추가하십시오. 예를 들면:

import logging
logging.warning('%s before you %s', 'Look', 'leap!')

이것은 다음과 같이 출력합니다:

WARNING:root:Look before you leap!

보시다시피, 이벤트 설명 메시지에 가변 데이터를 병합하는데 이전 %-스타일의 문자열 포매팅을 사용합니다. 이전 버전과의 호환성을 위한 것입니다: logging 패키지는 str.format() 과 string.Template 과 같은 새로운 포매팅 옵션 이전부터 존재해왔습니다. 이 새로운 포매팅 옵션 역시 지원되지만, 이 자습서의 범위를 벗어납니다: 좀 더 자세한 정보는 응용 프로그램 전체에서 특정 포맷 스타일 사용하기를 참조하세요.

표시된 메시지의 포맷 변경

메시지를 표시하는 데 사용되는 포맷을 변경하려면 사용할 format을 지정해야 합니다:

import logging
logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.DEBUG)
logging.debug('This message should appear on the console')
logging.info('So should this')
logging.warning('And this, too')

이것은 다음과 같이 인쇄합니다:

DEBUG:This message should appear on the console
INFO:So should this
WARNING:And this, too

앞의 예제에서 나타난 ‘root’ 가 사라졌음에 주목하십시오. 포맷 문자열에 나타날 수 있는 모든 것은 LogRecord 어트리뷰트 문서를 참고하게요. 하지만, 간단한 사용을 위해서는 levelname (심각도), message (이벤트 설명, 변수 데이터 포함) 와 아마도 발생 시각을 표시해야 할 것입니다. 이것은 다음 섹션에서 설명합니다.

메시지에 날짜/시간 표시

이벤트의 날짜와 시간을 표시하려면, 포맷 문자열에 ‘%(asctime)s’ 을 넣으십시오:

import logging
logging.basicConfig(format='%(asctime)s %(message)s')
logging.warning('is when this event was logged.')

이것은 이런 식으로 인쇄합니다:

2010-12-12 11:41:42,612 is when this event was logged.

(위에 나온) 날짜/시간 표시의 기본 포맷은 ISO8601 또는 RFC 3339 [https://datatracker.ietf.org/doc/html/rfc3339.html]와 같습니다. 날짜/시간의 포맷을 좀 더 제어해야 하는 경우, 이 예제에서와같이 basicConfig 에 datefmt 인자를 제공하십시오:

import logging
logging.basicConfig(format='%(asctime)s %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')
logging.warning('is when this event was logged.')

그러면 다음과 같이 표시됩니다:

12/12/2010 11:46:36 AM is when this event was logged.

datefmt 인자의 형식은 time.strftime() 에 의해 지원되는 것과 같습니다.

다음 단계

이것으로 기본 자습서를 마칩니다. 여러분이 로깅을 시작하고 사용하는데 충분할 겁니다. logging 패키지가 더 많은 것들을 제공하지만, 최선의 결과를 얻으려면 다음 섹션을 읽는 데 시간을 조금 더 투자하시기 바랍니다. 준비되었다면, 좋아하는 음료 한잔 준비하시고 계속합시다.

If your logging needs are simple, then use the above examples to incorporate logging into your own scripts, and if you run into problems or don’t understand something, please post a question on the comp.lang.python Usenet group (available at https://groups.google.com/g/comp.lang.python) and you should receive help before too long.

아직 계신가요? 위의 기본 섹션보다 약간 더 고급/심층적인 자습서를 제공하는 다음 몇 섹션을 계속 읽을 수 있습니다. 그 후에, 로깅 요리책을 살펴볼 수 있습니다.

고급 로깅 자습서

logging 라이브러리는 모듈 방식으로 구성되며, 로거, 처리기, 필터 및 포매터와 같은 여러 범주의 구성 요소를 제공합니다.

로거는 응용 프로그램 코드가 직접 사용하는 인터페이스를 노출합니다.

처리기는 (로거에 의해 만들어진) 로그 레코드를 적절한 목적지로 보냅니다.

필터는 출력할 로그 레코드를 결정하기 위한 보다 정밀한 기능을 제공합니다.

포매터는 최종 출력에서 로그 레코드의 배치를 지정합니다.

로그 이벤트 정보는 LogRecord 인스턴스를 통해 로거, 처리기, 필터 및 포매터 간에 전달됩니다.

로깅은 Logger 클래스(이하 로거 (loggers) 라고 합니다) 인스턴스의 메서드를 호출하여 수행됩니다. 각 인스턴스에는 이름이 있으며, 점(마침표)을 구분 기호로 사용하여 개념적으로는 이름 공간 계층 구조로 배열됩니다. 예를 들어, ‘scan’이라는 로거는 ‘scan.text’, ‘scan.html’ 및 ‘scan.pdf’ 로거의 부모입니다. 로거 이름은 원하는 어떤 것이건 될 수 있으며, 로그 된 메시지가 시작된 응용 프로그램 영역을 나타냅니다.

로거의 이름을 지을 때 사용할 좋은 규칙은 다음과 같이 로깅을 사용하는 각 모듈에서 모듈 수준 로거를 사용하는 것입니다:

logger = logging.getLogger(__name__)

이것은 로거 이름이 패키지/모듈 계층을 추적한다는 것을 의미하며, 로거 이름으로부터 이벤트가 기록되는 위치를 직관적으로 명확히 알 수 있습니다.

로거 계층의 뿌리를 루트 로거라고 합니다. 이것이 debug(), info(), warning(), error() 그리고 critical() 함수에 의해 사용되는 로거인데, 루트 로거의 같은 이름의 메서드들 호출합니다. 함수와 메서드는 같은 서명을 가집니다. 루트 로거의 이름은 로그 된 출력에 ‘root’ 로 인쇄됩니다.

물론 로그 메시지를 다른 대상에 기록하는 것도 가능합니다. 로그 메시지를 파일, HTTP GET/POST 위치, SMTP를 통한 전자 메일, 일반 소켓, 큐 또는 syslog 나 윈도우 NT 이벤트 로그와 같은 OS 특정 로깅 메커니즘에 쓰는 지원이 패키지에 포함되어 있습니다. 목적지는 처리기 (handler) 클래스에 의해 제공됩니다. 내장된 처리기 클래스에 의해 충족되지 않는 특별한 요구 사항이 있는 경우, 자체 로그 대상 클래스를 작성할 수 있습니다.

기본적으로, 로그 메시지에는 대상이 설정되지 않습니다. 자습서 예제에서와같이 basicConfig()를 사용하여 대상(가령 콘솔 또는 파일)을 지정할 수 있습니다. debug(), info(), warning(), error() 및 critical() 함수를 호출하면 목적지가 설정되어 있지 않은지 확인합니다; 설정되지 않았다면, 실제 메시지 출력을 하기 위해 루트 로거에 위임하기 전에, 콘솔(sys.stderr)을 대상으로 설정하고 표시되는 메시지의 기본 포맷을 설정합니다.

메시지에 대해 basicConfig() 에 의해 설정된 기본 포맷은 다음과 같습니다:

severity:logger name:message

포맷 문자열을 format 키워드 인자로 basicConfig() 에 전달하여 이를 변경할 수 있습니다. 포맷 문자열 작성 방법과 관련된 모든 옵션은 Formatter 객체를 참조하십시오.

로깅 흐름

로거 및 처리기에서 로그 이벤트 정보의 흐름은 다음 도표에 설명되어 있습니다.

로거

Logger 객체는 세 가지 작업을 합니다. 첫째, 응용 프로그램이 실행시간에 메시지를 기록 할 수 있도록 여러 메서드를 응용 프로그램 코드에 노출합니다. 둘째, 로거 객체는 심각도 (기본 필터링 장치) 또는 필터 객체에 따라 어떤 로그 메시지를 처리할지 결정합니다. 셋째, 로거 객체는 관련 로그 메시지를 관심 있는 모든 로그 처리기로 전달합니다.

로거 객체에서 가장 널리 사용되는 메서드는 두 가지 범주로 분류됩니다: 구성 및 메시지 전송

다음은 가장 일반적인 구성 메서드입니다:

Logger.setLevel()은 로거가 처리할 가장 낮은 심각도의 로그 메시지를 지정합니다. debug은 가장 낮은 내장 심각도 수준이고 critical은 가장 높은 내장 심각도입니다. 예를 들어, 심각도 수준이 INFO이면 로거는 INFO, WARNING, ERROR 및 CRITICAL 메시지만 처리하고 DEBUG 메시지는 무시합니다.

Logger.addHandler() 와 Logger.removeHandler() 는 로거 객체에서 처리기 객체를 추가하고 제거합니다. 처리기는 처리기에서 더욱 자세히 다룹니다.

Logger.addFilter() 와 Logger.removeFilter() 는 로거 객체에서 필터 객체를 추가하고 제거합니다. 필터는 Filter 객체에서 더욱 자세히 다룹니다.

생성 한 모든 로거에서 항상 이 메서드를 호출할 필요는 없습니다. 이 섹션의 마지막 두 단락을 참조하십시오.

로거 객체가 구성된 상태에서 다음 메서드는 로그 메시지를 만듭니다:

Logger.debug(), Logger.info(), Logger.warning(), Logger.error() 그리고 Logger.critical()은 모두 메시지 와 메서드 이름에 해당하는 수준으로 로그 레코드를 만듭니다. 메시지는 실제로는 포맷 문자열이며, %s, %d, %f 등의 표준 문자열 치환 문법을 포함 할 수 있습니다. 나머지 인자들은 메시지의 치환 필드에 해당하는 객체 목록입니다. **kwargs 의 경우, 로깅 메서드는 exc_info 라는 키워드에 대해서만 신경을 쓰고 예외 정보를 로깅 할지를 결정할 때 사용합니다.

Logger.exception() 은 Logger.error() 와 비슷한 로그 메시지를 생성합니다. 차이점은 Logger.exception() 가 스택 트레이스를 덤프한다는 것입니다. 예외 처리기에서만 이 메서드를 호출하십시오.

Logger.log() 는 명시적 인자로 로그 수준을 받아들입니다. 위에 나열된 로그 수준 편의 메서드를 사용하는 것보다 로깅 메시지를 만들 때 더 장황해지지만, 사용자 정의 로그 수준으로 로깅 하는 방법입니다.

getLogger() 는 이름이 제공되는 경우 지정된 이름을 가진 로거 인스턴스에 대한 참조를 반환하고, 그렇지 않으면 root 를 반환합니다. 이름은 마침표로 구분된 계층적 구조입니다. 같은 이름으로 getLogger() 를 여러 번 호출하면 같은 로거 객체에 대한 참조를 반환합니다. 계층적 목록에서 더 아래쪽에 있는 로거는 목록에서 상위에 있는 로거의 자식입니다. 예를 들어, 이름이 foo 인 로거가 주어지면, foo.bar, foo.bar.baz, 그리고 foo.bam 의 이름을 가진 로거는 모두 foo 의 자손입니다.

로거에는 실효 수준 이라는 개념이 있습니다. 수준이 로거에 명시적으로 설정되지 않은 경우, 부모 수준을 실효 수준으로 대신 사용합니다. 부모가 명시적 수준 집합을 가지고 있지 않으면, 다시 그것의 부모가 검사되고, 등등 - 명시적으로 설정된 수준이 발견될 때까지 모든 조상이 검색됩니다. 루트 로거는 항상 명시적인 수준 집합(기본적으로 WARNING)을 가지고 있습니다. 이벤트 처리 여부를 결정할 때, 로거의 실효 수준이 이벤트가 로거 처리기로 전달되는지를 판별하는 데 사용됩니다.

자식 로거는 조상 로거와 연관된 처리기로 메시지를 전달합니다. 이 때문에 응용 프로그램에서 사용하는 모든 로거에 대해 처리기를 정의하고 구성할 필요가 없습니다. 최상위 수준 로거에 대한 처리기를 구성하고 필요에 따라 자식 로거를 만드는 것으로 충분합니다. (그러나, 로거의 propagate 어트리뷰트를 False 로 설정하여 전파를 끌 수 있습니다.)

처리기

Handler 객체는 (로그 메시지의 심각도를 기반으로) 적절한 로그 메시지를 처리기의 지정된 대상으로 전달하는 역할을 합니다. Logger 객체는 addHandler() 메서드를 사용하여 0개 이상의 처리기 객체를 자신에게 추가 할 수 있습니다. 예를 들어, 응용 프로그램은 모든 로그 메시지를 로그 파일로 보내고, 에러(error)와 그 이상의 모든 로그 메시지를 표준 출력으로 보내고, 모든 심각한 에러(critical) 메시지를 전자 메일 주소로 보낼 수 있습니다. 이 시나리오에서는 각 처리기가 특정 심각도의 메시지를 특정 위치로 보내는 3개의 개별 처리기가 필요합니다.

표준 라이브러리에는 꽤 많은 처리기형이 포함되어있습니다 (유용한 처리기 참조). 자습서는 주로 StreamHandler 와 FileHandler 를 예제에서 사용합니다.

처리기에는 응용 프로그램 개발자가 직접 신경 써야 할 메서드가 거의 없습니다. 기본 제공 처리기 객체를 사용하는 (즉, 사용자 정의 처리기를 만들지 않는) 응용 프로그램 개발자와 관련이 있는 처리기 메서드는 다음과 같은 구성 메서드뿐입니다:

The setLevel() method, just as in logger objects, specifies the lowest severity that will be dispatched to the appropriate destination. Why are there two setLevel() methods? The level set in the logger determines which severity of messages it will pass to its handlers. The level set in each handler determines which messages that handler will send on.

setFormatter() 는 처리기가 사용할 포매터 객체를 선택합니다.

addFilter() 와 removeFilter() 는 각각 처리기에서 필터 객체를 구성하고 해제합니다.

응용 프로그램 코드는 Handler 의 인스턴스를 직접 인스턴스화해서 사용해서는 안 됩니다. 대신, Handler 클래스는 모든 처리기가 가져야 하는 인터페이스를 정의하고 자식 클래스가 사용할 수 있는 (또는 재정의할 수 있는) 기본 동작을 설정하는 베이스 클래스입니다.

포매터

포매터 객체는 로그 메시지의 최종 순서, 구조 및 내용을 구성합니다. 베이스 logging.Handler 클래스와는 달리, 응용 프로그램 코드는 포매터 클래스를 인스턴스화 할 수 있습니다. 응용 프로그램에 특별한 동작이 필요한 경우 포매터의 서브 클래스를 만들 수도 있습니다. 생성자는 세 가지 선택적 인자를 취합니다 – 메시지 포맷 문자열, 날짜 포맷 문자열 및 스타일 지시자.

logging.Formatter.__init__(fmt=None, datefmt=None, style='%')

메시지 포맷 문자열이 없으면, 기본값은 날 메시지를 사용하는 것입니다. 날짜 포맷 문자열이 없으면, 기본 날짜 형식은 다음과 같습니다:

%Y-%m-%d %H:%M:%S

with the milliseconds tacked on at the end. The style is one of '%', '{', or '$'. If one of these is not specified, then '%' will be used.

If the style is '%', the message format string uses %(<dictionary key>)s styled string substitution; the possible keys are documented in LogRecord 어트리뷰트. If the style is '{', the message format string is assumed to be compatible with str.format() (using keyword arguments), while if the style is '$' then the message format string should conform to what is expected by string.Template.substitute().

버전 3.2에서 변경: style 매개 변수를 추가했습니다.

다음 메시지 포맷 문자열은 사람이 읽을 수 있는 형식의 시간, 메시지의 심각도 및 메시지의 내용을 순서대로 기록합니다:

'%(asctime)s - %(levelname)s - %(message)s'

포매터는 사용자가 구성 할 수 있는 함수를 사용하여 레코드의 생성 시간을 튜플로 변환합니다. 기본적으로, time.localtime() 이 사용됩니다; 특정 포매터 인스턴스에 대해 이를 변경하려면, 인스턴스의 converter 어트리뷰트를 time.localtime() 또는 time.gmtime() 과 같은 서명을 가진 함수로 설정하십시오. 모든 포매터를 변경하려면, 예를 들어 모든 로깅 시간을 GMT로 표시하려면, Formatter 클래스의 converter 어트리뷰트를 설정하십시오 (GMT 표시를 위해 time.gmtime 으로).

로깅 구성

프로그래머는 세 가지 방법으로 로깅을 구성 할 수 있습니다:

위에 나열된 구성 메서드를 호출하는 파이썬 코드를 사용하여 로거, 처리기 및 포매터를 명시적으로 만듭니다.

로깅 구성 파일을 만들고, fileConfig() 함수를 사용하여 그것을 읽습니다.

구성 정보의 딕셔너리를 만들고, dictConfig() 함수에 전달합니다.

마지막 두 옵션에 대한 참조 설명서는 구성 함수를 참조하십시오. 다음 예제는 파이썬 코드를 사용하여 매우 단순한 로거, 콘솔 처리기 및 간단한 포매터를 구성합니다:

import logging

# create logger
logger = logging.getLogger('simple_example')
logger.setLevel(logging.DEBUG)

# create console handler and set level to debug
ch = logging.StreamHandler()
ch.setLevel(logging.DEBUG)

# create formatter
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

# add formatter to ch
ch.setFormatter(formatter)

# add ch to logger
logger.addHandler(ch)

# 'application' code
logger.debug('debug message')
logger.info('info message')
logger.warning('warn message')
logger.error('error message')
logger.critical('critical message')

명령행에서 이 모듈을 실행하면 다음과 같이 출력됩니다:

$ python simple_logging_module.py
2005-03-19 15:10:26,618 - simple_example - DEBUG - debug message
2005-03-19 15:10:26,620 - simple_example - INFO - info message
2005-03-19 15:10:26,695 - simple_example - WARNING - warn message
2005-03-19 15:10:26,697 - simple_example - ERROR - error message
2005-03-19 15:10:26,773 - simple_example - CRITICAL - critical message

다음의 파이썬 모듈은 위에 열거된 예제와 거의 같고 객체의 이름 만 다른 로거, 처리기 및 포매터를 생성합니다:

import logging
import logging.config

logging.config.fileConfig('logging.conf')

# create logger
logger = logging.getLogger('simpleExample')

# 'application' code
logger.debug('debug message')
logger.info('info message')
logger.warning('warn message')
logger.error('error message')
logger.critical('critical message')

logging.conf 파일은 이렇습니다:

[loggers]
keys=root,simpleExample

[handlers]
keys=consoleHandler

[formatters]
keys=simpleFormatter

[logger_root]
level=DEBUG
handlers=consoleHandler

[logger_simpleExample]
level=DEBUG
handlers=consoleHandler
qualname=simpleExample
propagate=0

[handler_consoleHandler]
class=StreamHandler
level=DEBUG
formatter=simpleFormatter
args=(sys.stdout,)

[formatter_simpleFormatter]
format=%(asctime)s - %(name)s - %(levelname)s - %(message)s

출력은 구성 파일 기반이 아닌 예제와 거의 같습니다:

$ python simple_logging_config.py
2005-03-19 15:38:55,977 - simpleExample - DEBUG - debug message
2005-03-19 15:38:55,979 - simpleExample - INFO - info message
2005-03-19 15:38:56,054 - simpleExample - WARNING - warn message
2005-03-19 15:38:56,055 - simpleExample - ERROR - error message
2005-03-19 15:38:56,130 - simpleExample - CRITICAL - critical message

구성 파일 접근법이 파이썬 코드 접근법보다 몇 가지 장점이 있음을 알 수 있습니다. 주로 구성과 코드의 분리와 코더가 아니라도 로깅 속성을 쉽게 수정할 수 있다는 것입니다.

경고

fileConfig() 함수는 기본 매개 변수 disable_existing_loggers 를 취하는데, 하위 호환성을 위해 기본값은 True 입니다. 이것들은 여러분이 원하는 것일 수도 있고 아닐 수도 있습니다. 왜냐하면 fileConfig() 호출 전에 존재하는 모든 비 루트 로거들이, 구성에서 명시적으로 명명되지 않는 한, 비활성화되기 때문입니다. 자세한 내용은 참조 설명서를 참조하고, 원한다면 이 매개 변수에 False 를 지정하십시오.

dictConfig() 에 전달된 딕셔너리 또한 disable_existing_loggers 키로 논리값을 지정할 수 있습니다. 딕셔너리에 명시적으로 지정되지 않으면 기본적으로 True 로 해석됩니다. 이것은 위에서 설명한 로거 비활성화 동작으로 이어지는데, 여러분이 원하는 것이 아닐 수도 있습니다. 이 경우 키에 명시적으로 False 값을 제공하십시오.

구성 파일에서 참조되는 클래스 이름은 logging 모듈에 상대적이거나, 일반적인 임포트 메커니즘을 사용하여 결정할 수 있는 절댓값이어야 합니다. 따라서, WatchedFileHandler (logging 모듈에 상대적) 또는 mypackage.mymodule.MyHandler (패키지 mypackage 와 모듈 mymodule 에 정의된 클래스, 여기서 mypackage 는 파이썬 임포트 경로에서 사용 가능해야 합니다).

파이썬 3.2에서는 구성 정보를 보관하는 딕셔너리를 사용하여 로깅을 구성하는 새로운 방법이 도입되었습니다. 이는 위에 설명된 구성 파일 기반 접근 방식의 기능을 제공하며, 새로운 응용 프로그램 및 배포에 권장되는 구성 방법입니다. 파이썬 딕셔너리가 구성 정보를 저장하는 데 사용되고, 다른 방법을 사용하여 해당 딕셔너리를 채울 수 있으므로 더 많은 구성 옵션을 갖게 됩니다. 예를 들어, 구성 딕셔너리를 채우는데 JSON 형식의 구성 파일이나, YAML 처리 기능에 액세스할 수 있는 경우, YAML 형식의 파일을 사용할 수 있습니다. 물론, 파이썬 코드로 딕셔너리를 만들거나, 소켓을 통해 피클 된 형태로 수신하거나, 그 밖의 응용 프로그램에 적합한 어떤 방식도 사용할 수 있습니다.

다음은 새로운 딕셔너리 기반 접근 방식으로 YAML 형식으로 위와 같이 구성한 예입니다:

version: 1
formatters:
  simple:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
handlers:
  console:
    class: logging.StreamHandler
    level: DEBUG
    formatter: simple
    stream: ext://sys.stdout
loggers:
  simpleExample:
    level: DEBUG
    handlers: [console]
    propagate: no
root:
  level: DEBUG
  handlers: [console]

딕셔너리를 사용하여 로깅 하는 방법에 대한 자세한 내용은 구성 함수를 참조하십시오.

구성이 제공되지 않으면 어떻게 되는가

If no logging configuration is provided, it is possible to have a situation where a logging event needs to be output, but no handlers can be found to output the event.

The event is output using a ‘handler of last resort’, stored in lastResort. This internal handler is not associated with any logger, and acts like a StreamHandler which writes the event description message to the current value of sys.stderr (therefore respecting any redirections which may be in effect). No formatting is done on the message - just the bare event description message is printed. The handler’s level is set to WARNING, so all events at this and greater severities will be output.

버전 3.2에서 변경: 3.2 이전의 파이썬 버전의 경우 동작은 다음과 같습니다:

If raiseExceptions is False (production mode), the event is silently dropped.

If raiseExceptions is True (development mode), a message ‘No handlers could be found for logger X.Y.Z’ is printed once.

To obtain the pre-3.2 behaviour, lastResort can be set to None.

라이브러리 로깅 구성

로깅을 사용하는 라이브러리를 개발할 때, 라이브러리에서 로깅을 사용하는 방법을 문서로 만들어야 합니다 - 예를 들어, 사용된 로거의 이름. 또한, 로깅 구성에 대한 고려가 필요합니다. 사용하는 응용 프로그램이 로깅을 사용하지 않고 라이브러리 코드가 로깅을 호출하면, (앞 절에서 설명했듯이) 심각도가 WARNING 이상인 이벤트는 sys.stderr 에 출력됩니다. 이것이 최상의 기본 동작인 것으로 간주합니다.

어떤 이유로 로깅 구성이 없을 때 이 메시지가 인쇄되는 것을 원하지 않는다면, 라이브러리의 최상위 로거에 아무것도 하지 않는 처리기를 연결할 수 있습니다. 이렇게 하면 메시지가 인쇄되는 것을 피할 수 있습니다. 라이브러리의 이벤트를 위한 처리기가 항상 존재하기 때문입니다: 단지 아무런 출력도 만들지 않을 뿐입니다. 라이브러리 사용자가 응용 프로그램이 사용하기 위해 로깅을 구성하면, 아마도 그 구성이 어떤 처리기를 추가할 것이고, 수준이 적절하게 구성된 경우 라이브러리에서 이루어진 로깅 호출은 그 처리기로 정상적으로 출력을 보낼 것입니다.

아무것도 하지 않는 처리기가 logging 패키지에 포함되어 있습니다: NullHandler (파이썬 3.1부터). 이 처리기의 인스턴스는 라이브러리가 사용하는 로깅 이름 공간의 최상위 로거에 추가될 수 있습니다 (만약 로깅 구성이 없는 경우 라이브러리가 로깅한 이벤트가 sys.stderr 에 출력되는 것을 막으려면). 라이브러리 foo 에 의한 모든 로깅이 ‘foo.x’, ‘foo.x.y’ 등과 일치하는 이름을 가진 로거들만 사용한다면, 다음과 같은 코드가:

import logging
logging.getLogger('foo').addHandler(logging.NullHandler())

원하는 효과를 주어야 합니다. 만약 조직이 여러 라이브러리를 만든다면, 지정된 로거 이름으로 단순한 ‘foo’ 대신에 ‘orgname.foo’를 사용할 수 있습니다.

참고

It is strongly advised that you do not log to the root logger in your library. Instead, use a logger with a unique and easily identifiable name, such as the __name__ for your library’s top-level package or module. Logging to the root logger will make it difficult or impossible for the application developer to configure the logging verbosity or handlers of your library as they wish.

참고

NullHandler 이외의 처리기를 라이브러리의 로거에 추가하지 않는 것이 좋습니다. 이것은 처리기 구성이 라이브러리를 사용하는 응용 프로그램 개발자의 특권이기 때문입니다. 응용 프로그램 개발자는 사용자와 응용 프로그램에 가장 적합한 처리기가 무엇인지 알고 있습니다. 여러분이 처리기를 ‘이면에서’ 추가하면, 단위 테스트를 수행하고 그들의 요구사항에 맞는 로그를 전달하는 작업을 방해할 수 있습니다.

로깅 수준

로깅 수준의 숫자 값은 다음 표에 나와 있습니다. 이것은 주로 여러분 자신의 수준을 정의하고 사전 정의된 수준에 상대적인 특정 값을 갖도록 하려는 경우 관심의 대상입니다. 같은 숫자 값을 가진 수준을 정의하면 미리 정의된 값을 덮어씁니다; 사전 정의된 이름이 유실됩니다.

수준

숫자 값

CRITICAL

50

ERROR

40

WARNING

30

INFO

20

DEBUG

10

NOTSET

0

또한, 수준은 개발자가 설정하거나 저장된 로깅 구성을 로드하여 로거와 연관될 수 있습니다. 로깅 메서드가 로거에 호출되면, 로거는 자체 수준을 메서드 호출과 연관된 수준과 비교합니다. 로거 수준이 메서드 호출보다 높으면 실제로 로깅 메시지가 생성되지 않습니다. 이것은 로그 출력의 상세도를 제어하는 기본 메커니즘입니다.

로깅 메시지는 LogRecord 클래스의 인스턴스로 인코딩됩니다. 로거가 실제로 이벤트를 로그 하기로 하면, LogRecord 인스턴스가 로깅 메시지로부터 만들어집니다.

로깅 메시지는 Handler 클래스의 서브 클래스의 인스턴스인 처리기 (handlers) 를 통한 전달 메커니즘을 적용받게 됩니다. 처리기는 로그된 메시지(LogRecord 형식)가 대상 독자(가령 최종 사용자, 지원 데스크 직원, 시스템 관리자, 개발자)에게 유용한 특정 위치(또는 위치 집합)에 도달하도록 할 책임이 있습니다. 처리기로는 특정 목적지를 위한 LogRecord 인스턴스가 전달됩니다. 각 로거에는 0개 이상의 처리기가 연관될 수 있습니다 (Logger 의 addHandler() 메서드를 통해). 로거에 직접 연관된 모든 처리기뿐만 아니라, (로거의 propagate 플래그가 거짓 값으로 설정되어 있지 않은 한, 그 지점에서 부모 처리기로의 전달이 멈춥니다) 로거의 모든 조상과 연관된 모든 처리기가 메시지를 전달하도록 호출됩니다.

로거와 마찬가지로, 처리기도 연관된 수준을 가질 수 있습니다. 처리기의 수준은 로거의 수준과 같은 방식으로 필터의 역할을 합니다. 처리기가 실제로 이벤트를 전달하기로 하면, emit() 메서드가 목적지로 메시지를 보내기 위해 사용됩니다. Handler 의 대부분의 사용자 정의 서브 클래스는 이 emit() 를 재정의해야 합니다.

사용자 정의 수준

여러분 자신의 수준을 정의하는 것이 가능하지만 필요하지는 않은데, 현재의 수준이 실무 경험에 근거하여 선택되었기 때문입니다. 하지만, 사용자 정의 수준이 필요하다고 확신하는 경우, 이를 수행할 때 많은 주의를 기울여야 합니다. 라이브러리를 개발하고 있다면 사용자 지정 수준을 정의하는 것은 매우 나쁜 생각일 수 있습니다. 왜냐하면, 여러 라이브러리 작성자가 모두 자신의 사용자 정의 수준을 정의하면, 주어진 숫자 값이 라이브러리마다 각기 다른 것을 의미 할 수 있으므로, 사용 중인 개발자가 함께 사용하는 여러 라이브러리의 로깅 결과를 제어하거나 해석하는 것이 어려울 수 있기 때문입니다.

유용한 처리기

베이스 Handler 클래스 외에도 많은 유용한 서브 클래스가 제공됩니다:

StreamHandler 인스턴스는 스트림(파일류 객체)에 메시지를 보냅니다.

FileHandler 인스턴스는 디스크 파일에 메시지를 보냅니다.

BaseRotatingHandler 는 특정 지점에서 로그 파일을 회전시키는 처리기의 베이스 클래스입니다. 직접 인스턴스화하는 것은 아닙니다. 대신 RotatingFileHandler 또는 TimedRotatingFileHandler 를 사용하십시오.

RotatingFileHandler 인스턴스는 디스크 파일에 메시지를 보내는데, 최대 로그 파일 크기와 로그 파일 회전을 지원합니다.

TimedRotatingFileHandler 인스턴스는 디스크 파일에 메시지를 보내는데, 일정한 시간 간격으로 로그 파일을 회전시킵니다.

SocketHandler 인스턴스는 TCP/IP 소켓에 메시지를 보냅니다. 3.4부터, 유닉스 도메인 소켓도 지원됩니다.

DatagramHandler 인스턴스는 UDP 소켓에 메시지를 보냅니다. 3.4부터, 유닉스 도메인 소켓도 지원됩니다.

SMTPHandler 인스턴스는 지정된 전자 우편 주소로 메시지를 보냅니다.

SysLogHandler 인스턴스는 유닉스 syslog 데몬(원격 기계에 있는 것도 가능합니다)에 메시지를 보냅니다.

NTEventLogHandler 인스턴스는 윈도우 NT/2000/XP 이벤트 로그에 메시지를 보냅니다.

MemoryHandler 인스턴스는 메모리에 있는 버퍼에 메시지를 보내는데, 특정 기준이 만족 될 때마다 플러시 됩니다.

HTTPHandler 인스턴스는 GET 또는 POST 을 사용해서 HTTP 서버에 메시지를 보냅니다.

WatchedFileHandler 인스턴스는 그들이 로깅하고 있는 파일을 감시합니다. 파일이 변경되면 닫히고 파일 이름을 사용하여 다시 열립니다. 이 처리기는 유닉스 계열 시스템에서만 유용합니다; 윈도우는 사용된 하부 메커니즘을 지원하지 않습니다.

QueueHandler 인스턴스는 queue 또는 multiprocessing 모듈에 구현된 것과 같은 큐로 메시지를 보냅니다.

NullHandler instances do nothing with error messages. They are used by library developers who want to use logging, but want to avoid the ‘No handlers could be found for logger XXX’ message which can be displayed if the library user has not configured logging. See 라이브러리 로깅 구성 for more information.

Added in version 3.1: NullHandler 클래스.

Added in version 3.2: QueueHandler 클래스.

NullHandler, StreamHandler 와 FileHandler 클래스는 코어 logging 패키지에 정의되어 있습니다. 다른 처리기는 하위 모듈인 logging.handlers 에 정의되어 있습니다. (구성 기능을 위한, 또 다른 하위 모듈 logging.config 도 있습니다.)

로그된 메시지는 Formatter 클래스의 인스턴스를 통해 표시를 위해 포맷됩니다. % 연산자와 딕셔너리와 함께 사용하기에 적합한 포맷 문자열로 초기화됩니다.

For formatting multiple messages in a batch, instances of BufferingFormatter can be used. In addition to the format string (which is applied to each message in the batch), there is provision for header and trailer format strings.

로거 수준과 처리기 수준을 기반으로 필터링하는 것만으로는 충분하지 않은 경우, Logger 및 Handler 인스턴스에 (addFilter() 메서드를 통해) Filter 인스턴스를 추가 할 수 있습니다. 메시지를 더 처리하기로 하기 전에, 로거와 처리기는 모든 필터에 허락을 요청합니다. 한 필터라도 거짓 값을 반환하면 메시지는 더 처리되지 않습니다.

기본적인 Filter 기능은 특정 로거 이름으로 필터링하는 것을 지원합니다. 이 기능을 사용하면, 명명된 로거와 그 자식으로 보낸 메시지는 필터를 통과하도록 허용되고, 다른 모든 메시지는 삭제됩니다.

로깅 중에 발생하는 예외

logging 패키지는 프로덕션에서 로깅 하는 동안 발생하는 예외를 삼키도록 설계되었습니다. 이는 로깅 이벤트를 처리하는 동안 발생하는 에러(가령 잘못된 로깅 구성, 네트워크 또는 기타 유사한 에러)가 로깅을 사용하는 응용 프로그램을 조기에 종료시키지 않도록 하기 위한 것입니다.

SystemExit 과 KeyboardInterrupt 예외는 절대 삼켜지지 않습니다. Handler 서브 클래스의 emit() 메서드가 실행되는 동안 발생하는 다른 예외는 handleError() 메서드에 전달됩니다.

Handler 에 있는 handleError() 의 기본 구현은 모듈 수준 변수 raiseExceptions 가 설정되어 있는지를 검사합니다. 설정되어있으면, 트레이스백이 sys.stderr 에 인쇄됩니다. 설정되지 않았으면 예외를 삼킵니다.

참고

raiseExceptions 의 기본값은 True 입니다. 개발 중에는, 보통 발생하는 예외에 대한 알림을 받기를 원하기 때문입니다. 프로덕션 용도로는 raiseExceptions 를 False 로 설정하는 것이 좋습니다.

임의의 객체를 메시지로 사용하기

앞의 절과 예제에서 이벤트를 로깅할 때 전달되는 메시지는 문자열이라고 가정했습니다. 그러나 이것만 가능한 것은 아닙니다. 임의의 객체를 메시지로 전달할 수 있으며, 로깅 시스템이 이를 문자열 표현으로 변환해야 할 때 __str__() 메서드가 호출됩니다. 사실, 원한다면, 문자열 표현을 계산하는 것을 완전히 피할 수 있습니다 - 예를 들어, SocketHandler 는 이벤트를 피클링해서 와이어를 통해 전송하는 방식으로 이벤트를 보냅니다.

최적화

메시지 인자의 포매팅은 피할 수 없을 때까지 연기됩니다. 하지만, 로깅 메서드에 전달된 인자를 계산하는 것 또한 비용이 많이들 수 있고, 로거가 이벤트를 버리는 경우에는 수행하지 않고 싶을 수 있습니다. 꼭 해야 할 것을 결정하기 위해서, level 인자를 취하고 해당 수준의 호출이 로거에 의해 이벤트가 생성되면 참을 반환하는 isEnabledFor() 메서드를 호출 할 수 있습니다. 다음과 같은 코드를 작성할 수 있습니다:

if logger.isEnabledFor(logging.DEBUG):
    logger.debug('Message with %s, %s', expensive_func1(),
                                        expensive_func2())

so that if the logger’s threshold is set above DEBUG, the calls to expensive_func1 and expensive_func2 are never made.

참고

때에 따라, isEnabledFor() 자체가 원하는 것보다 더 비쌀 수 있습니다 (예를 들어, 명시적 수준이 로거 계층의 상단에서만 설정된 깊이 중첩된 로거의 경우). 그러한 경우 (또는 꽉 짜인 루프 내에서 메서드를 호출하지 않으려는 경우) 지역이나 인스턴스 변수에 isEnabledFor() 의 호출 결과를 캐시하고, 매번 메서드를 호출하는 대신 그 값을 사용할 수 있습니다. 이러한 캐시 된 값은 응용 프로그램이 실행되는 동안 로깅 구성이 동적으로 변경될 때(그리 흔한 경우는 아닙니다)만 재계산될 필요가 있습니다.

로깅 정보를 수집하는 방법을 보다 정밀하게 제어해야 하는 특정 응용 프로그램에 대해 수행할 수 있는 다른 최적화가 있습니다. 다음은 필요하지 않은 로깅 처리를 피하고자 수행할 수 있는 작업 목록입니다:

수집하고 싶지 않은 것

수집하는 것을 피하는 방법

호출이 이루어진 위치에 관한 정보.

logging._srcfile 을 None 으로 설정하십시오. 이렇게 하면 sys._getframe() 호출을 피할 수 있는데, PyPy(sys._getframe() 을 사용하는 코드의 속도를 높일 수 없습니다)와 같은 환경에서 코드 속도를 높이는 데 도움이 됩니다.

스레딩 정보.

Set logging.logThreads to False.

Current process ID (os.getpid())

Set logging.logProcesses to False.

Current process name when using multiprocessing to manage multiple processes.

Set logging.logMultiprocessing to False.

Current asyncio.Task name when using asyncio.

Set logging.logAsyncioTasks to False.

또한, 코어 logging 모듈에는 기본 처리기만 포함됩니다. logging.handlers 와 logging.config 를 임포트 하지 않으면 메모리를 차지하지 않습니다.

Other resources

더 보기

모듈 logging

logging 모듈에 관한 API 레퍼런스.

모듈 logging.config

logging 모듈용 구성 API.

모듈 logging.handlers

logging 모듈에 포함된 유용한 처리기.

로깅 요리책

로깅 요리책

저자:

Vinay Sajip <vinay_sajip at red-dove dot com>

This page contains a number of recipes related to logging, which have been found useful in the past. For links to tutorial and reference information, please see Other resources.

여러 모듈에서 로깅 사용하기

logging.getLogger('someLogger') 를 여러 번 호출하면 같은 로거 객체에 대한 참조가 반환됩니다. 같은 모듈 내에서뿐만 아니라, 같은 파이썬 인터프리터 프로세스에 있는 한, 여러 모듈에서도 마찬가지입니다. 참조가 같은 객체를 가리킨다는 것에 더해, 응용 프로그램 코드는 하나의 모듈에서 부모 로거를 정의 및 구성하고 별도의 모듈에서 자식 로거를 생성 (구성하지 않음) 할 수 있으며, 자식에 대한 모든 로거 호출은 부모로 전달됩니다. 다음은 메인 모듈입니다:

import logging
import auxiliary_module

# create logger with 'spam_application'
logger = logging.getLogger('spam_application')
logger.setLevel(logging.DEBUG)
# create file handler which logs even debug messages
fh = logging.FileHandler('spam.log')
fh.setLevel(logging.DEBUG)
# create console handler with a higher log level
ch = logging.StreamHandler()
ch.setLevel(logging.ERROR)
# create formatter and add it to the handlers
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
fh.setFormatter(formatter)
ch.setFormatter(formatter)
# add the handlers to the logger
logger.addHandler(fh)
logger.addHandler(ch)

logger.info('creating an instance of auxiliary_module.Auxiliary')
a = auxiliary_module.Auxiliary()
logger.info('created an instance of auxiliary_module.Auxiliary')
logger.info('calling auxiliary_module.Auxiliary.do_something')
a.do_something()
logger.info('finished auxiliary_module.Auxiliary.do_something')
logger.info('calling auxiliary_module.some_function()')
auxiliary_module.some_function()
logger.info('done with auxiliary_module.some_function()')

다음은 보조 모듈입니다:

import logging

# create logger
module_logger = logging.getLogger('spam_application.auxiliary')

class Auxiliary:
    def __init__(self):
        self.logger = logging.getLogger('spam_application.auxiliary.Auxiliary')
        self.logger.info('creating an instance of Auxiliary')

    def do_something(self):
        self.logger.info('doing something')
        a = 1 + 1
        self.logger.info('done doing something')

def some_function():
    module_logger.info('received a call to "some_function"')

출력은 이렇게 됩니다:

2005-03-23 23:47:11,663 - spam_application - INFO -
   creating an instance of auxiliary_module.Auxiliary
2005-03-23 23:47:11,665 - spam_application.auxiliary.Auxiliary - INFO -
   creating an instance of Auxiliary
2005-03-23 23:47:11,665 - spam_application - INFO -
   created an instance of auxiliary_module.Auxiliary
2005-03-23 23:47:11,668 - spam_application - INFO -
   calling auxiliary_module.Auxiliary.do_something
2005-03-23 23:47:11,668 - spam_application.auxiliary.Auxiliary - INFO -
   doing something
2005-03-23 23:47:11,669 - spam_application.auxiliary.Auxiliary - INFO -
   done doing something
2005-03-23 23:47:11,670 - spam_application - INFO -
   finished auxiliary_module.Auxiliary.do_something
2005-03-23 23:47:11,671 - spam_application - INFO -
   calling auxiliary_module.some_function()
2005-03-23 23:47:11,672 - spam_application.auxiliary - INFO -
   received a call to 'some_function'
2005-03-23 23:47:11,673 - spam_application - INFO -
   done with auxiliary_module.some_function()

여러 스레드에서 로깅 하기

여러 스레드에서 로깅 하는데 특별한 노력이 필요하지는 않습니다. 다음 예제에서는 메인 (최초) 스레드와 다른 스레드에서의 로깅을 보여줍니다:

import logging
import threading
import time

def worker(arg):
    while not arg['stop']:
        logging.debug('Hi from myfunc')
        time.sleep(0.5)

def main():
    logging.basicConfig(level=logging.DEBUG, format='%(relativeCreated)6d %(threadName)s %(message)s')
    info = {'stop': False}
    thread = threading.Thread(target=worker, args=(info,))
    thread.start()
    while True:
        try:
            logging.debug('Hello from main')
            time.sleep(0.75)
        except KeyboardInterrupt:
            info['stop'] = True
            break
    thread.join()

if __name__ == '__main__':
    main()

실행하면 스크립트는 다음과 같이 인쇄합니다:

   0 Thread-1 Hi from myfunc
   3 MainThread Hello from main
 505 Thread-1 Hi from myfunc
 755 MainThread Hello from main
1007 Thread-1 Hi from myfunc
1507 MainThread Hello from main
1508 Thread-1 Hi from myfunc
2010 Thread-1 Hi from myfunc
2258 MainThread Hello from main
2512 Thread-1 Hi from myfunc
3009 MainThread Hello from main
3013 Thread-1 Hi from myfunc
3515 Thread-1 Hi from myfunc
3761 MainThread Hello from main
4017 Thread-1 Hi from myfunc
4513 MainThread Hello from main
4518 Thread-1 Hi from myfunc

예상대로 로그 출력이 산재해 있음을 볼 수 있습니다. 물론, 이 방법은 여기에 표시된 것보다 많은 스레드에서도 작동합니다.

다중 처리기 및 포매터

로거는 일반 파이썬 객체입니다. addHandler() 메서드에는 추가할 수 있는 처리기의 수에 대한 최소 또는 최대 할당량이 없습니다. 때로는 응용 프로그램이 모든 심각도의 모든 메시지를 텍스트 파일에 기록하는 동시에, 에러 또는 그 이상을 콘솔에 기록하는 것이 유용 할 수 있습니다. 이렇게 설정하려면, 적절한 처리기를 구성하기만 하면 됩니다. 응용 프로그램 코드의 로깅 호출은 변경되지 않습니다. 다음은 앞의 간단한 모듈 기반 구성 예제를 약간 수정 한 것입니다:

import logging

logger = logging.getLogger('simple_example')
logger.setLevel(logging.DEBUG)
# create file handler which logs even debug messages
fh = logging.FileHandler('spam.log')
fh.setLevel(logging.DEBUG)
# create console handler with a higher log level
ch = logging.StreamHandler()
ch.setLevel(logging.ERROR)
# create formatter and add it to the handlers
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
ch.setFormatter(formatter)
fh.setFormatter(formatter)
# add the handlers to logger
logger.addHandler(ch)
logger.addHandler(fh)

# 'application' code
logger.debug('debug message')
logger.info('info message')
logger.warning('warn message')
logger.error('error message')
logger.critical('critical message')

‘응용 프로그램’ 코드는 여러 처리기에 신경 쓰지 않습니다. 변경된 것은 fh 라는 새로운 처리기의 추가 및 구성뿐입니다.

중요도가 높거나 낮은 필터를 사용하여 새 처리기를 만드는 기능은 응용 프로그램을 작성하고 테스트할 때 매우 유용합니다. 디버깅을 위해 많은 print 문을 사용하는 대신에 logger.debug 를 사용하십시오: 나중에 삭제하거나 주석 처리해야 할 print 문과 달리, logger.debug 문은 소스 코드에서 그대로 유지될 수 있고, 그들을 다시 필요로 할 때까지 휴면 상태로 남아 있습니다. 그때, 필요한 유일한 변경은 로거 또는 처리기의 심각도 수준을 DEBUG로 수정하는 것입니다.

여러 대상으로 로깅 하기

다른 메시지 포맷으로 다른 상황에서 콘솔과 파일에 기록하려고 한다고 가정 해 봅시다. DEBUG 이상 수준의 메시지를 파일에 기록하고, 수준 INFO 이상인 메시지를 콘솔에 기록하려고 한다고 가정 해보십시오. 또한, 타임스탬프가 파일에는 포함되어야 하지만, 콘솔 메시지에는 없어야 한다고 가정합시다. 이렇게 하면 됩니다:

import logging

# set up logging to file - see previous section for more details
logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
                    datefmt='%m-%d %H:%M',
                    filename='/tmp/myapp.log',
                    filemode='w')
# define a Handler which writes INFO messages or higher to the sys.stderr
console = logging.StreamHandler()
console.setLevel(logging.INFO)
# set a format which is simpler for console use
formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
# tell the handler to use this format
console.setFormatter(formatter)
# add the handler to the root logger
logging.getLogger('').addHandler(console)

# Now, we can log to the root logger, or any other logger. First the root...
logging.info('Jackdaws love my big sphinx of quartz.')

# Now, define a couple of other loggers which might represent areas in your
# application:

logger1 = logging.getLogger('myapp.area1')
logger2 = logging.getLogger('myapp.area2')

logger1.debug('Quick zephyrs blow, vexing daft Jim.')
logger1.info('How quickly daft jumping zebras vex.')
logger2.warning('Jail zesty vixen who grabbed pay from quack.')
logger2.error('The five boxing wizards jump quickly.')

실행하면 콘솔에는 다음과 같이 출력됩니다.

root        : INFO     Jackdaws love my big sphinx of quartz.
myapp.area1 : INFO     How quickly daft jumping zebras vex.
myapp.area2 : WARNING  Jail zesty vixen who grabbed pay from quack.
myapp.area2 : ERROR    The five boxing wizards jump quickly.

파일에는 이렇게 기록됩니다.

10-22 22:19 root         INFO     Jackdaws love my big sphinx of quartz.
10-22 22:19 myapp.area1  DEBUG    Quick zephyrs blow, vexing daft Jim.
10-22 22:19 myapp.area1  INFO     How quickly daft jumping zebras vex.
10-22 22:19 myapp.area2  WARNING  Jail zesty vixen who grabbed pay from quack.
10-22 22:19 myapp.area2  ERROR    The five boxing wizards jump quickly.

보시다시피 DEBUG 메시지는 파일에만 표시됩니다. 다른 메시지는 두 목적지로 전송됩니다.

이 예제는 콘솔과 파일 처리기를 사용하지만, 여러분이 선택하는 처리기의 수나 조합에 제약이 없습니다.

Note that the above choice of log filename /tmp/myapp.log implies use of a standard location for temporary files on POSIX systems. On Windows, you may need to choose a different directory name for the log - just ensure that the directory exists and that you have the permissions to create and update files in it.

Custom handling of levels

Sometimes, you might want to do something slightly different from the standard handling of levels in handlers, where all levels above a threshold get processed by a handler. To do this, you need to use filters. Let’s look at a scenario where you want to arrange things as follows:

Send messages of severity INFO and WARNING to sys.stdout

Send messages of severity ERROR and above to sys.stderr

Send messages of severity DEBUG and above to file app.log

Suppose you configure logging with the following JSON:

{
    "version": 1,
    "disable_existing_loggers": false,
    "formatters": {
        "simple": {
            "format": "%(levelname)-8s - %(message)s"
        }
    },
    "handlers": {
        "stdout": {
            "class": "logging.StreamHandler",
            "level": "INFO",
            "formatter": "simple",
            "stream": "ext://sys.stdout"
        },
        "stderr": {
            "class": "logging.StreamHandler",
            "level": "ERROR",
            "formatter": "simple",
            "stream": "ext://sys.stderr"
        },
        "file": {
            "class": "logging.FileHandler",
            "formatter": "simple",
            "filename": "app.log",
            "mode": "w"
        }
    },
    "root": {
        "level": "DEBUG",
        "handlers": [
            "stderr",
            "stdout",
            "file"
        ]
    }
}

This configuration does almost what we want, except that sys.stdout would show messages of severity ERROR and only events of this severity and higher will be tracked as well as INFO and WARNING messages. To prevent this, we can set up a filter which excludes those messages and add it to the relevant handler. This can be configured by adding a filters section parallel to formatters and handlers:

{
    "filters": {
        "warnings_and_below": {
            "()" : "__main__.filter_maker",
            "level": "WARNING"
        }
    }
}

and changing the section on the stdout handler to add it:

{
    "stdout": {
        "class": "logging.StreamHandler",
        "level": "INFO",
        "formatter": "simple",
        "stream": "ext://sys.stdout",
        "filters": ["warnings_and_below"]
    }
}

A filter is just a function, so we can define the filter_maker (a factory function) as follows:

def filter_maker(level):
    level = getattr(logging, level)

    def filter(record):
        return record.levelno <= level

    return filter

This converts the string argument passed in to a numeric level, and returns a function which only returns True if the level of the passed in record is at or below the specified level. Note that in this example I have defined the filter_maker in a test script main.py that I run from the command line, so its module will be __main__ - hence the __main__.filter_maker in the filter configuration. You will need to change that if you define it in a different module.

With the filter added, we can run main.py, which in full is:

import json
import logging
import logging.config

CONFIG = '''
{
    "version": 1,
    "disable_existing_loggers": false,
    "formatters": {
        "simple": {
            "format": "%(levelname)-8s - %(message)s"
        }
    },
    "filters": {
        "warnings_and_below": {
            "()" : "__main__.filter_maker",
            "level": "WARNING"
        }
    },
    "handlers": {
        "stdout": {
            "class": "logging.StreamHandler",
            "level": "INFO",
            "formatter": "simple",
            "stream": "ext://sys.stdout",
            "filters": ["warnings_and_below"]
        },
        "stderr": {
            "class": "logging.StreamHandler",
            "level": "ERROR",
            "formatter": "simple",
            "stream": "ext://sys.stderr"
        },
        "file": {
            "class": "logging.FileHandler",
            "formatter": "simple",
            "filename": "app.log",
            "mode": "w"
        }
    },
    "root": {
        "level": "DEBUG",
        "handlers": [
            "stderr",
            "stdout",
            "file"
        ]
    }
}
'''

def filter_maker(level):
    level = getattr(logging, level)

    def filter(record):
        return record.levelno <= level

    return filter

logging.config.dictConfig(json.loads(CONFIG))
logging.debug('A DEBUG message')
logging.info('An INFO message')
logging.warning('A WARNING message')
logging.error('An ERROR message')
logging.critical('A CRITICAL message')

And after running it like this:

python main.py 2>stderr.log >stdout.log

We can see the results are as expected:

$ more *.log
::::::::::::::
app.log
::::::::::::::
DEBUG    - A DEBUG message
INFO     - An INFO message
WARNING  - A WARNING message
ERROR    - An ERROR message
CRITICAL - A CRITICAL message
::::::::::::::
stderr.log
::::::::::::::
ERROR    - An ERROR message
CRITICAL - A CRITICAL message
::::::::::::::
stdout.log
::::::::::::::
INFO     - An INFO message
WARNING  - A WARNING message

구성 서버 예제

다음은 로깅 구성 서버를 사용하는 모듈의 예입니다:

import logging
import logging.config
import time
import os

# read initial config file
logging.config.fileConfig('logging.conf')

# create and start listener on port 9999
t = logging.config.listen(9999)
t.start()

logger = logging.getLogger('simpleExample')

try:
    # loop through logging calls to see the difference
    # new configurations make, until Ctrl+C is pressed
    while True:
        logger.debug('debug message')
        logger.info('info message')
        logger.warning('warn message')
        logger.error('error message')
        logger.critical('critical message')
        time.sleep(5)
except KeyboardInterrupt:
    # cleanup
    logging.config.stopListening()
    t.join()

다음은 파일 이름을 받아서, 그 파일을 새 로깅 구성으로 (이진 인코딩된 길이를 적절하게 앞에 붙여서) 서버로 보내는 스크립트입니다:

#!/usr/bin/env python
import socket, sys, struct

with open(sys.argv[1], 'rb') as f:
    data_to_send = f.read()

HOST = 'localhost'
PORT = 9999
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print('connecting...')
s.connect((HOST, PORT))
print('sending config...')
s.send(struct.pack('>L', len(data_to_send)))
s.send(data_to_send)
s.close()
print('complete')

블록 하는 처리기 다루기

Sometimes you have to get your logging handlers to do their work without blocking the thread you’re logging from. This is common in web applications, though of course it also occurs in other scenarios.

흔히 느린 행동을 보이는 범인은 SMTPHandler 입니다: 개발자의 통제 밖에 있는 여러 가지 이유로, 전자 우편을 보내는 데 오랜 시간이 걸릴 수 있습니다 (예를 들어, 잘 동작하지 않는 메일 또는 네트워크 인프라). 그러나 거의 모든 네트워크 기반 처리기는 블록 할 수 있습니다. SocketHandler 작업도 너무 느린 DNS 질의를 이면에서 수행 할 수 있습니다 (그리고 이 질의는 여러분의 통제 밖에 있는, 파이썬 계층 아래의 소켓 라이브러리 코드 깊숙이 있을 수 있습니다).

한 가지 해결책은 두 부분으로 된 접근법을 사용하는 것입니다. 첫 번째 부분에서는, 성능이 중요한 스레드에서 액세스하는 로거에 QueueHandler 만 붙입니다. 그들은 단순히 큐에 씁니다. 충분한 용량으로 큐의 크기를 조정하거나, 크기의 상한이 없도록 초기화 할 수 있습니다. 큐에 대한 쓰기는 일반적으로 신속하게 받아들여지지만, 코드에서 예방책으로 queue.Full 예외를 잡아야 할 것입니다. 코드에 성능이 중요한 스레드가 있는 라이브러리 개발자인 경우, 코드를 사용할 다른 개발자의 이익을 위해 이것을 (여러분의 로거에 QueueHandlers 만 붙이라는 제안과 함께) 문서로 만들어야 합니다.

해결책의 두 번째 부분은 QueueListener며, 이는 QueueHandler 에 상응하여 설계되었습니다. QueueListener 는 매우 간단합니다: 큐와 처리기를 넘겨주면 QueueHandlers (또는 LogRecords 의 다른 소스)에서 보낸 LogRecord를 큐에서 수신하는 내부 스레드를 시작합니다. LogRecords 는 큐에서 제거되고 처리를 위해 처리기로 전달됩니다.

별도의 QueueListener 클래스를 사용하면 같은 인스턴스를 사용하여 여러 개의 QueueHandlers 를 처리할 수 있다는 장점이 있습니다. 이것은 특별한 이점 없이 처리기당 하나의 스레드를 먹게 되는 기존의 처리기 클래스의 스레드 버전을 만드는 것보다 자원 친화적입니다.

이 두 클래스를 사용하는 예제는 다음과 같습니다 (임포트 생략):

que = queue.Queue(-1)  # no limit on size
queue_handler = QueueHandler(que)
handler = logging.StreamHandler()
listener = QueueListener(que, handler)
root = logging.getLogger()
root.addHandler(queue_handler)
formatter = logging.Formatter('%(threadName)s: %(message)s')
handler.setFormatter(formatter)
listener.start()
# The log output will display the thread which generated
# the event (the main thread) rather than the internal
# thread which monitors the internal queue. This is what
# you want to happen.
root.warning('Look out!')
listener.stop()

실행하면, 다음과 같은 결과를 만듭니다:

MainThread: Look out!

참고

Although the earlier discussion wasn’t specifically talking about async code, but rather about slow logging handlers, it should be noted that when logging from async code, network and even file handlers could lead to problems (blocking the event loop) because some logging is done from asyncio internals. It might be best, if any async code is used in an application, to use the above approach for logging, so that any blocking code runs only in the QueueListener thread.

버전 3.5에서 변경: 파이썬 3.5 이전 버전에서는, QueueListener 는 항상 큐에서 받은 모든 메시지를 초기화될 때 제공된 모든 처리기로 전달했습니다. (이것은 큐가 채워질 때 수준 필터링이 모두 반대편에서 행해졌다고 가정했기 때문입니다.) 3.5 이후부터, 이 동작은 키워드 인자 respect_handler_level=True 를 리스너의 생성자에 전달함으로써 변경될 수 있습니다. 이렇게 할 때, 리스너는 각 메시지의 수준을 처리기의 수준과 비교하여, 적절한 메시지만 처리기에 전달되도록 합니다.

네트워크에서 로깅 이벤트 보내고 받기

네트워크를 통해 로깅 이벤트를 보내고, 받는 쪽에서 처리하려고 한다고 합시다. 이렇게 하는 간단한 방법은 SocketHandler 인스턴스를 보내는 쪽의 루트 로거에 연결하는 것입니다:

import logging, logging.handlers

rootLogger = logging.getLogger('')
rootLogger.setLevel(logging.DEBUG)
socketHandler = logging.handlers.SocketHandler('localhost',
                    logging.handlers.DEFAULT_TCP_LOGGING_PORT)
# don't bother with a formatter, since a socket handler sends the event as
# an unformatted pickle
rootLogger.addHandler(socketHandler)

# Now, we can log to the root logger, or any other logger. First the root...
logging.info('Jackdaws love my big sphinx of quartz.')

# Now, define a couple of other loggers which might represent areas in your
# application:

logger1 = logging.getLogger('myapp.area1')
logger2 = logging.getLogger('myapp.area2')

logger1.debug('Quick zephyrs blow, vexing daft Jim.')
logger1.info('How quickly daft jumping zebras vex.')
logger2.warning('Jail zesty vixen who grabbed pay from quack.')
logger2.error('The five boxing wizards jump quickly.')

수신 측에서는 socketserver 모듈을 사용하여 수신기를 구성할 수 있습니다. 기본적인 작업 예제는 다음과 같습니다:

import pickle
import logging
import logging.handlers
import socketserver
import struct

class LogRecordStreamHandler(socketserver.StreamRequestHandler):
    """Handler for a streaming logging request.

    This basically logs the record using whatever logging policy is
    configured locally.
    """

    def handle(self):
        """
        Handle multiple requests - each expected to be a 4-byte length,
        followed by the LogRecord in pickle format. Logs the record
        according to whatever policy is configured locally.
        """
        while True:
            chunk = self.connection.recv(4)
            if len(chunk) < 4:
                break
            slen = struct.unpack('>L', chunk)[0]
            chunk = self.connection.recv(slen)
            while len(chunk) < slen:
                chunk = chunk + self.connection.recv(slen - len(chunk))
            obj = self.unPickle(chunk)
            record = logging.makeLogRecord(obj)
            self.handleLogRecord(record)

    def unPickle(self, data):
        return pickle.loads(data)

    def handleLogRecord(self, record):
        # if a name is specified, we use the named logger rather than the one
        # implied by the record.
        if self.server.logname is not None:
            name = self.server.logname
        else:
            name = record.name
        logger = logging.getLogger(name)
        # N.B. EVERY record gets logged. This is because Logger.handle
        # is normally called AFTER logger-level filtering. If you want
        # to do filtering, do it at the client end to save wasting
        # cycles and network bandwidth!
        logger.handle(record)

class LogRecordSocketReceiver(socketserver.ThreadingTCPServer):
    """
    Simple TCP socket-based logging receiver suitable for testing.
    """

    allow_reuse_address = True

    def __init__(self, host='localhost',
                 port=logging.handlers.DEFAULT_TCP_LOGGING_PORT,
                 handler=LogRecordStreamHandler):
        socketserver.ThreadingTCPServer.__init__(self, (host, port), handler)
        self.abort = 0
        self.timeout = 1
        self.logname = None

    def serve_until_stopped(self):
        import select
        abort = 0
        while not abort:
            rd, wr, ex = select.select([self.socket.fileno()],
                                       [], [],
                                       self.timeout)
            if rd:
                self.handle_request()
            abort = self.abort

def main():
    logging.basicConfig(
        format='%(relativeCreated)5d %(name)-15s %(levelname)-8s %(message)s')
    tcpserver = LogRecordSocketReceiver()
    print('About to start TCP server...')
    tcpserver.serve_until_stopped()

if __name__ == '__main__':
    main()

먼저 서버를 실행한 다음 클라이언트를 실행합니다. 클라이언트 쪽에서는 콘솔에 아무것도 인쇄되지 않습니다. 서버 측에서 다음과 같은 내용이 보여야 합니다.:

About to start TCP server...
   59 root            INFO     Jackdaws love my big sphinx of quartz.
   59 myapp.area1     DEBUG    Quick zephyrs blow, vexing daft Jim.
   69 myapp.area1     INFO     How quickly daft jumping zebras vex.
   69 myapp.area2     WARNING  Jail zesty vixen who grabbed pay from quack.
   69 myapp.area2     ERROR    The five boxing wizards jump quickly.

Note that there are some security issues with pickle in some scenarios. If these affect you, you can use an alternative serialization scheme by overriding the makePickle() method and implementing your alternative there, as well as adapting the above script to use your alternative serialization.

Running a logging socket listener in production

To run a logging listener in production, you may need to use a process-management tool such as Supervisor [http://supervisord.org/]. Here is a Gist [https://gist.github.com/vsajip/4b227eeec43817465ca835ca66f75e2b] which provides the bare-bones files to run the above functionality using Supervisor. It consists of the following files:

File

Purpose

prepare.sh

A Bash script to prepare the environment for testing

supervisor.conf

The Supervisor configuration file, which has entries for the listener and a multi-process web application

ensure_app.sh

A Bash script to ensure that Supervisor is running with the above configuration

log_listener.py

The socket listener program which receives log events and records them to a file

main.py

A simple web application which performs logging via a socket connected to the listener

webapp.json

A JSON configuration file for the web application

client.py

A Python script to exercise the web application

The web application uses Gunicorn [https://gunicorn.org/], which is a popular web application server that starts multiple worker processes to handle requests. This example setup shows how the workers can write to the same log file without conflicting with one another — they all go through the socket listener.

To test these files, do the following in a POSIX environment:

Download the Gist [https://gist.github.com/vsajip/4b227eeec43817465ca835ca66f75e2b] as a ZIP archive using the Download ZIP button.

Unzip the above files from the archive into a scratch directory.

In the scratch directory, run bash prepare.sh to get things ready. This creates a run subdirectory to contain Supervisor-related and log files, and a venv subdirectory to contain a virtual environment into which bottle, gunicorn and supervisor are installed.

Run bash ensure_app.sh to ensure that Supervisor is running with the above configuration.

Run venv/bin/python client.py to exercise the web application, which will lead to records being written to the log.

Inspect the log files in the run subdirectory. You should see the most recent log lines in files matching the pattern app.log*. They won’t be in any particular order, since they have been handled concurrently by different worker processes in a non-deterministic way.

You can shut down the listener and the web application by running venv/bin/supervisorctl -c supervisor.conf shutdown.

You may need to tweak the configuration files in the unlikely event that the configured ports clash with something else in your test environment.

로그 출력에 문맥 정보 추가

로깅 호출에 전달된 매개 변수 외에도 로깅 출력에 문맥 정보가 포함되기 원하는 경우가 있습니다. 예를 들어, 네트워크 응용 프로그램에서, (원격 클라이언트의 사용자 이름 또는 IP 주소와 같은) 클라이언트별 정보를 로그에 기록하는 것이 바람직 할 수 있습니다. 이를 달성하기 위해 extra 매개 변수를 사용할 수는 있지만, 이러한 방식으로 정보를 전달하는 것이 항상 편리하지는 않습니다. 연결마다 Logger 인스턴스를 만들고 싶을지 모르지만, 이러한 인스턴스는 가비지 수집되지 않기 때문에 좋지 않습니다. Logger 인스턴스의 수가 응용 프로그램 로깅에 사용하고자 하는 세분성 수준에 의존적일 때 이것이 실제로 문제가 되지는 않지만, Logger 인스턴스의 수가 실질적으로 무제한이 되면 관리하기 어려울 수 있습니다.

문맥 정보 전달에 LoggerAdapters 사용하기

로깅 이벤트 정보와 함께 출력되는 문맥 정보를 전달하는 쉬운 방법은 LoggerAdapter 클래스를 사용하는 것입니다. 이 클래스는 Logger처럼 보이도록 설계되어 있어서, debug(), info(), warning(), error(), exception(), critical() 및 log()를 호출할 수 있습니다. 이 메서드들은 Logger 에 있는 것과 똑같은 서명을 가지므로, 두 형의 인스턴스를 같은 의미로 사용할 수 있습니다.

LoggerAdapter 의 인스턴스를 생성할 때, Logger 인스턴스와 문맥 정보가 포함된 딕셔너리류 객체를 전달합니다. LoggerAdapter 의 인스턴스에서 로깅 메서드 중 하나를 호출하면, 생성자에 전달된 하위 Logger 인스턴스에 호출을 위임하고, 이 호출에 문맥 정보를 전달하도록 배치합니다. 다음은 LoggerAdapter 코드에서 발췌한 내용입니다:

def debug(self, msg, /, *args, **kwargs):
    """
    Delegate a debug call to the underlying logger, after adding
    contextual information from this adapter instance.
    """
    msg, kwargs = self.process(msg, kwargs)
    self.logger.debug(msg, *args, **kwargs)

LoggerAdapter 의 process() 메서드는 문맥 정보가 로그 출력에 추가되는 곳입니다. 로깅 호출의 메시지 및 키워드 인자를 받아서, 하부 로거에 대한 호출에서 사용될 (대체로) 수정된 버전을 돌려줍니다. 이 메서드의 기본 구현은 메시지는 그대로 두고, 키워드 인자에 생성자로 전달된 딕셔너리류 객체를 값으로 갖는 ‘extra’ 키를 삽입합니다. 물론, 어댑터에 대한 호출에서 ‘extra’ 키워드 인자를 전달한 경우 자동으로 덮어씁니다.

‘extra’를 사용하는 장점은, 딕셔너리류 객체에 들어있는 값이 LogRecord 인스턴스의 __dict__에 병합되어, 키에 대해 알고 있는 Formatter 인스턴스로 사용자 정의된 문자열을 사용할 수 있게 된다는 것입니다. 다른 방법이 필요한 경우, 가령 메시지 문자열의 앞이나 뒤에 문맥 정보를 덧붙이려는 경우, LoggerAdapter 의 서브 클래스를 만들고, 필요한 작업을 수행하기 위해 process() 를 재정의해야 합니다. 다음은 간단한 예제입니다:

class CustomAdapter(logging.LoggerAdapter):
    """
    This example adapter expects the passed in dict-like object to have a
    'connid' key, whose value in brackets is prepended to the log message.
    """
    def process(self, msg, kwargs):
        return '[%s] %s' % (self.extra['connid'], msg), kwargs

이런 식으로 사용할 수 있습니다:

logger = logging.getLogger(__name__)
adapter = CustomAdapter(logger, {'connid': some_conn_id})

그러면 어댑터에 로그 하는 모든 이벤트는 로그 메시지 앞에 some_conn_id 값이 붙습니다.

딕셔너리 이외의 객체를 사용하여 문맥 정보 전달하기

실제 딕셔너리를 LoggerAdapter 에 전달할 필요는 없습니다 - 로깅에 딕셔너리처럼 보일 수 있도록, __getitem__ 과 __iter__ 를 구현하는 클래스의 인스턴스를 전달할 수 있습니다. 값을 동적으로 생성하려는 경우 (반면에 딕셔너리에 들어있는 값은 바뀌지 않습니다) 유용합니다.

문맥 정보 전달에 필터 사용하기

사용자 정의 Filter를 사용하여 로그 출력에 문맥 정보를 추가할 수도 있습니다. Filter 인스턴스는 전달된 LogRecords 를 수정할 수 있는데, 어트리뷰트를 추가해서 적절한 포맷 문자열이나 필요하다면 사용자 정의 Formatter를 사용해서 출력되도록 할 수 있습니다.

예를 들어 웹 응용 프로그램에서, 처리 중인 요청(또는 적어도 그것의 흥미로운 부분)을 스레드 로컬 (threading.local) 변수에 저장한 다음, Filter 에서 액세스해서, 요청에서 온 정보를 - 원격 IP 주소와 원격 사용자의 사용자 이름이라고 합시다 - 위의 LoggerAdapter 예제에서와같이 어트리뷰트 이름 ‘ip’와 ‘user’를 사용하여 LogRecord 에 추가할 수 있습니다. 이 경우 같은 포맷 문자열을 사용하여 위에 표시된 것과 비슷한 출력을 얻을 수 있습니다. 다음은 스크립트 예입니다:

import logging
from random import choice

class ContextFilter(logging.Filter):
    """
    This is a filter which injects contextual information into the log.

    Rather than use actual contextual information, we just use random
    data in this demo.
    """

    USERS = ['jim', 'fred', 'sheila']
    IPS = ['123.231.231.123', '127.0.0.1', '192.168.0.1']

    def filter(self, record):

        record.ip = choice(ContextFilter.IPS)
        record.user = choice(ContextFilter.USERS)
        return True

if __name__ == '__main__':
    levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL)
    logging.basicConfig(level=logging.DEBUG,
                        format='%(asctime)-15s %(name)-5s %(levelname)-8s IP: %(ip)-15s User: %(user)-8s %(message)s')
    a1 = logging.getLogger('a.b.c')
    a2 = logging.getLogger('d.e.f')

    f = ContextFilter()
    a1.addFilter(f)
    a2.addFilter(f)
    a1.debug('A debug message')
    a1.info('An info message with %s', 'some parameters')
    for x in range(10):
        lvl = choice(levels)
        lvlname = logging.getLevelName(lvl)
        a2.log(lvl, 'A message at %s level with %d %s', lvlname, 2, 'parameters')

실행하면 다음과 같은 결과가 나옵니다:

2010-09-06 22:38:15,292 a.b.c DEBUG    IP: 123.231.231.123 User: fred     A debug message
2010-09-06 22:38:15,300 a.b.c INFO     IP: 192.168.0.1     User: sheila   An info message with some parameters
2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 127.0.0.1       User: sheila   A message at CRITICAL level with 2 parameters
2010-09-06 22:38:15,300 d.e.f ERROR    IP: 127.0.0.1       User: jim      A message at ERROR level with 2 parameters
2010-09-06 22:38:15,300 d.e.f DEBUG    IP: 127.0.0.1       User: sheila   A message at DEBUG level with 2 parameters
2010-09-06 22:38:15,300 d.e.f ERROR    IP: 123.231.231.123 User: fred     A message at ERROR level with 2 parameters
2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 192.168.0.1     User: jim      A message at CRITICAL level with 2 parameters
2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 127.0.0.1       User: sheila   A message at CRITICAL level with 2 parameters
2010-09-06 22:38:15,300 d.e.f DEBUG    IP: 192.168.0.1     User: jim      A message at DEBUG level with 2 parameters
2010-09-06 22:38:15,301 d.e.f ERROR    IP: 127.0.0.1       User: sheila   A message at ERROR level with 2 parameters
2010-09-06 22:38:15,301 d.e.f DEBUG    IP: 123.231.231.123 User: fred     A message at DEBUG level with 2 parameters
2010-09-06 22:38:15,301 d.e.f INFO     IP: 123.231.231.123 User: fred     A message at INFO level with 2 parameters

Use of contextvars

Since Python 3.7, the contextvars module has provided context-local storage which works for both threading and asyncio processing needs. This type of storage may thus be generally preferable to thread-locals. The following example shows how, in a multi-threaded environment, logs can populated with contextual information such as, for example, request attributes handled by web applications.

For the purposes of illustration, say that you have different web applications, each independent of the other but running in the same Python process and using a library common to them. How can each of these applications have their own log, where all logging messages from the library (and other request processing code) are directed to the appropriate application’s log file, while including in the log additional contextual information such as client IP, HTTP request method and client username?

Let’s assume that the library can be simulated by the following code:

# webapplib.py
import logging
import time

logger = logging.getLogger(__name__)

def useful():
    # Just a representative event logged from the library
    logger.debug('Hello from webapplib!')
    # Just sleep for a bit so other threads get to run
    time.sleep(0.01)

We can simulate the multiple web applications by means of two simple classes, Request and WebApp. These simulate how real threaded web applications work - each request is handled by a thread:

# main.py
import argparse
from contextvars import ContextVar
import logging
import os
from random import choice
import threading
import webapplib

logger = logging.getLogger(__name__)
root = logging.getLogger()
root.setLevel(logging.DEBUG)

class Request:
    """
    A simple dummy request class which just holds dummy HTTP request method,
    client IP address and client username
    """
    def __init__(self, method, ip, user):
        self.method = method
        self.ip = ip
        self.user = user

# A dummy set of requests which will be used in the simulation - we'll just pick
# from this list randomly. Note that all GET requests are from 192.168.2.XXX
# addresses, whereas POST requests are from 192.16.3.XXX addresses. Three users
# are represented in the sample requests.

REQUESTS = [
    Request('GET', '192.168.2.20', 'jim'),
    Request('POST', '192.168.3.20', 'fred'),
    Request('GET', '192.168.2.21', 'sheila'),
    Request('POST', '192.168.3.21', 'jim'),
    Request('GET', '192.168.2.22', 'fred'),
    Request('POST', '192.168.3.22', 'sheila'),
]

# Note that the format string includes references to request context information
# such as HTTP method, client IP and username

formatter = logging.Formatter('%(threadName)-11s %(appName)s %(name)-9s %(user)-6s %(ip)s %(method)-4s %(message)s')

# Create our context variables. These will be filled at the start of request
# processing, and used in the logging that happens during that processing

ctx_request = ContextVar('request')
ctx_appname = ContextVar('appname')

class InjectingFilter(logging.Filter):
    """
    A filter which injects context-specific information into logs and ensures
    that only information for a specific webapp is included in its log
    """
    def __init__(self, app):
        self.app = app

    def filter(self, record):
        request = ctx_request.get()
        record.method = request.method
        record.ip = request.ip
        record.user = request.user
        record.appName = appName = ctx_appname.get()
        return appName == self.app.name

class WebApp:
    """
    A dummy web application class which has its own handler and filter for a
    webapp-specific log.
    """
    def __init__(self, name):
        self.name = name
        handler = logging.FileHandler(name + '.log', 'w')
        f = InjectingFilter(self)
        handler.setFormatter(formatter)
        handler.addFilter(f)
        root.addHandler(handler)
        self.num_requests = 0

    def process_request(self, request):
        """
        This is the dummy method for processing a request. It's called on a
        different thread for every request. We store the context information into
        the context vars before doing anything else.
        """
        ctx_request.set(request)
        ctx_appname.set(self.name)
        self.num_requests += 1
        logger.debug('Request processing started')
        webapplib.useful()
        logger.debug('Request processing finished')

def main():
    fn = os.path.splitext(os.path.basename(__file__))[0]
    adhf = argparse.ArgumentDefaultsHelpFormatter
    ap = argparse.ArgumentParser(formatter_class=adhf, prog=fn,
                                 description='Simulate a couple of web '
                                             'applications handling some '
                                             'requests, showing how request '
                                             'context can be used to '
                                             'populate logs')
    aa = ap.add_argument
    aa('--count', '-c', type=int, default=100, help='How many requests to simulate')
    options = ap.parse_args()

    # Create the dummy webapps and put them in a list which we can use to select
    # from randomly
    app1 = WebApp('app1')
    app2 = WebApp('app2')
    apps = [app1, app2]
    threads = []
    # Add a common handler which will capture all events
    handler = logging.FileHandler('app.log', 'w')
    handler.setFormatter(formatter)
    root.addHandler(handler)

    # Generate calls to process requests
    for i in range(options.count):
        try:
            # Pick an app at random and a request for it to process
            app = choice(apps)
            request = choice(REQUESTS)
            # Process the request in its own thread
            t = threading.Thread(target=app.process_request, args=(request,))
            threads.append(t)
            t.start()
        except KeyboardInterrupt:
            break

    # Wait for the threads to terminate
    for t in threads:
        t.join()

    for app in apps:
        print('%s processed %s requests' % (app.name, app.num_requests))

if __name__ == '__main__':
    main()

If you run the above, you should find that roughly half the requests go into app1.log and the rest into app2.log, and the all the requests are logged to app.log. Each webapp-specific log will contain only log entries for only that webapp, and the request information will be displayed consistently in the log (i.e. the information in each dummy request will always appear together in a log line). This is illustrated by the following shell output:

~/logging-contextual-webapp$ python main.py
app1 processed 51 requests
app2 processed 49 requests
~/logging-contextual-webapp$ wc -l *.log
  153 app1.log
  147 app2.log
  300 app.log
  600 total
~/logging-contextual-webapp$ head -3 app1.log
Thread-3 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
Thread-3 (process_request) app1 webapplib jim    192.168.3.21 POST Hello from webapplib!
Thread-5 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
~/logging-contextual-webapp$ head -3 app2.log
Thread-1 (process_request) app2 __main__  sheila 192.168.2.21 GET  Request processing started
Thread-1 (process_request) app2 webapplib sheila 192.168.2.21 GET  Hello from webapplib!
Thread-2 (process_request) app2 __main__  jim    192.168.2.20 GET  Request processing started
~/logging-contextual-webapp$ head app.log
Thread-1 (process_request) app2 __main__  sheila 192.168.2.21 GET  Request processing started
Thread-1 (process_request) app2 webapplib sheila 192.168.2.21 GET  Hello from webapplib!
Thread-2 (process_request) app2 __main__  jim    192.168.2.20 GET  Request processing started
Thread-3 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
Thread-2 (process_request) app2 webapplib jim    192.168.2.20 GET  Hello from webapplib!
Thread-3 (process_request) app1 webapplib jim    192.168.3.21 POST Hello from webapplib!
Thread-4 (process_request) app2 __main__  fred   192.168.2.22 GET  Request processing started
Thread-5 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
Thread-4 (process_request) app2 webapplib fred   192.168.2.22 GET  Hello from webapplib!
Thread-6 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
~/logging-contextual-webapp$ grep app1 app1.log | wc -l
153
~/logging-contextual-webapp$ grep app2 app2.log | wc -l
147
~/logging-contextual-webapp$ grep app1 app.log | wc -l
153
~/logging-contextual-webapp$ grep app2 app.log | wc -l
147

Imparting contextual information in handlers

Each Handler has its own chain of filters. If you want to add contextual information to a LogRecord without leaking it to other handlers, you can use a filter that returns a new LogRecord instead of modifying it in-place, as shown in the following script:

import copy
import logging

def filter(record: logging.LogRecord):
    record = copy.copy(record)
    record.user = 'jim'
    return record

if __name__ == '__main__':
    logger = logging.getLogger()
    logger.setLevel(logging.INFO)
    handler = logging.StreamHandler()
    formatter = logging.Formatter('%(message)s from %(user)-8s')
    handler.setFormatter(formatter)
    handler.addFilter(filter)
    logger.addHandler(handler)

    logger.info('A log message')

여러 프로세스에서 단일 파일에 로깅 하기

logging 이 스레드-안전하고, 단일 프로세스의 여러 스레드에서 단일 파일로 로깅 하는 것이 지원되지만, 파이썬에서 여러 프로세스가 단일 파일에 액세스하는 것을 직렬화하는 표준적인 방법이 없으므로, 여러 프로세스에서 단일 파일로 로깅 하는 것은 지원되지 않습니다. 여러 프로세스에서 하나의 파일에 로그 해야 하는 경우, 이 작업을 수행하는 한 가지 방법은 모든 프로세스가 로그를 SocketHandler 에 기록하고, 소켓에서 읽어서 파일로 로그 하는 소켓 서버를 구현하는 별도의 프로세스를 사용하는 것입니다. (원한다면, 기존 프로세스 중 하나에서 한 스레드가 이 기능을 전담하도록 할 수 있습니다.) 이 섹션에서 이 접근법을 더 자세하게 설명하고, 여러분의 응용 프로그램에 적용하기 위한 출발점으로 사용할 수 있는 작동하는 소켓 수신기를 제공합니다.

You could also write your own handler which uses the Lock class from the multiprocessing module to serialize access to the file from your processes. The stdlib FileHandler and subclasses do not make use of multiprocessing.

또는, Queue 와 QueueHandler 를 사용하여, 모든 로깅 이벤트를 다중 프로세스 응용 프로그램의 프로세스 중 하나에 보낼 수 있습니다. 다음 예제 스크립트는 이렇게 하는 방법을 보여줍니다; 예제에서 별도의 리스너 프로세스가 다른 프로세스가 보낸 이벤트를 수신하고 자체 로깅 구성에 따라 이벤트를 기록합니다. 이 예제가 한 가지 방법만을 보여 주지만 (예를 들어, 별도의 리스너 프로세스 대신 리스너 스레드를 사용할 수도 있습니다 – 구현은 비슷할 것입니다), 리스너와 응용 프로그램의 다른 프로세스가 완전히 다른 로깅 구성을 사용하도록 허용하고, 여러분 자신의 특별한 요구 사항을 충족하는 코드의 기초로 사용할 수 있습니다:

# You'll need these imports in your own code
import logging
import logging.handlers
import multiprocessing

# Next two import lines for this demo only
from random import choice, random
import time

#
# Because you'll want to define the logging configurations for listener and workers, the
# listener and worker process functions take a configurer parameter which is a callable
# for configuring logging for that process. These functions are also passed the queue,
# which they use for communication.
#
# In practice, you can configure the listener however you want, but note that in this
# simple example, the listener does not apply level or filter logic to received records.
# In practice, you would probably want to do this logic in the worker processes, to avoid
# sending events which would be filtered out between processes.
#
# The size of the rotated files is made small so you can see the results easily.
def listener_configurer():
    root = logging.getLogger()
    h = logging.handlers.RotatingFileHandler('mptest.log', 'a', 300, 10)
    f = logging.Formatter('%(asctime)s %(processName)-10s %(name)s %(levelname)-8s %(message)s')
    h.setFormatter(f)
    root.addHandler(h)

# This is the listener process top-level loop: wait for logging events
# (LogRecords)on the queue and handle them, quit when you get a None for a
# LogRecord.
def listener_process(queue, configurer):
    configurer()
    while True:
        try:
            record = queue.get()
            if record is None:  # We send this as a sentinel to tell the listener to quit.
                break
            logger = logging.getLogger(record.name)
            logger.handle(record)  # No level or filter logic applied - just do it!
        except Exception:
            import sys, traceback
            print('Whoops! Problem:', file=sys.stderr)
            traceback.print_exc(file=sys.stderr)

# Arrays used for random selections in this demo

LEVELS = [logging.DEBUG, logging.INFO, logging.WARNING,
          logging.ERROR, logging.CRITICAL]

LOGGERS = ['a.b.c', 'd.e.f']

MESSAGES = [
    'Random message #1',
    'Random message #2',
    'Random message #3',
]

# The worker configuration is done at the start of the worker process run.
# Note that on Windows you can't rely on fork semantics, so each process
# will run the logging configuration code when it starts.
def worker_configurer(queue):
    h = logging.handlers.QueueHandler(queue)  # Just the one handler needed
    root = logging.getLogger()
    root.addHandler(h)
    # send all messages, for demo; no other level or filter logic applied.
    root.setLevel(logging.DEBUG)

# This is the worker process top-level loop, which just logs ten events with
# random intervening delays before terminating.
# The print messages are just so you know it's doing something!
def worker_process(queue, configurer):
    configurer(queue)
    name = multiprocessing.current_process().name
    print('Worker started: %s' % name)
    for i in range(10):
        time.sleep(random())
        logger = logging.getLogger(choice(LOGGERS))
        level = choice(LEVELS)
        message = choice(MESSAGES)
        logger.log(level, message)
    print('Worker finished: %s' % name)

# Here's where the demo gets orchestrated. Create the queue, create and start
# the listener, create ten workers and start them, wait for them to finish,
# then send a None to the queue to tell the listener to finish.
def main():
    queue = multiprocessing.Queue(-1)
    listener = multiprocessing.Process(target=listener_process,
                                       args=(queue, listener_configurer))
    listener.start()
    workers = []
    for i in range(10):
        worker = multiprocessing.Process(target=worker_process,
                                         args=(queue, worker_configurer))
        workers.append(worker)
        worker.start()
    for w in workers:
        w.join()
    queue.put_nowait(None)
    listener.join()

if __name__ == '__main__':
    main()

위의 스크립트 변형은 로깅을 메인 프로세스의 별도의 스레드에서 유지합니다:

import logging
import logging.config
import logging.handlers
from multiprocessing import Process, Queue
import random
import threading
import time

def logger_thread(q):
    while True:
        record = q.get()
        if record is None:
            break
        logger = logging.getLogger(record.name)
        logger.handle(record)

def worker_process(q):
    qh = logging.handlers.QueueHandler(q)
    root = logging.getLogger()
    root.setLevel(logging.DEBUG)
    root.addHandler(qh)
    levels = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
              logging.CRITICAL]
    loggers = ['foo', 'foo.bar', 'foo.bar.baz',
               'spam', 'spam.ham', 'spam.ham.eggs']
    for i in range(100):
        lvl = random.choice(levels)
        logger = logging.getLogger(random.choice(loggers))
        logger.log(lvl, 'Message no. %d', i)

if __name__ == '__main__':
    q = Queue()
    d = {
        'version': 1,
        'formatters': {
            'detailed': {
                'class': 'logging.Formatter',
                'format': '%(asctime)s %(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
            }
        },
        'handlers': {
            'console': {
                'class': 'logging.StreamHandler',
                'level': 'INFO',
            },
            'file': {
                'class': 'logging.FileHandler',
                'filename': 'mplog.log',
                'mode': 'w',
                'formatter': 'detailed',
            },
            'foofile': {
                'class': 'logging.FileHandler',
                'filename': 'mplog-foo.log',
                'mode': 'w',
                'formatter': 'detailed',
            },
            'errors': {
                'class': 'logging.FileHandler',
                'filename': 'mplog-errors.log',
                'mode': 'w',
                'level': 'ERROR',
                'formatter': 'detailed',
            },
        },
        'loggers': {
            'foo': {
                'handlers': ['foofile']
            }
        },
        'root': {
            'level': 'DEBUG',
            'handlers': ['console', 'file', 'errors']
        },
    }
    workers = []
    for i in range(5):
        wp = Process(target=worker_process, name='worker %d' % (i + 1), args=(q,))
        workers.append(wp)
        wp.start()
    logging.config.dictConfig(d)
    lp = threading.Thread(target=logger_thread, args=(q,))
    lp.start()
    # At this point, the main process could do some useful work of its own
    # Once it's done that, it can wait for the workers to terminate...
    for wp in workers:
        wp.join()
    # And now tell the logging thread to finish up, too
    q.put(None)
    lp.join()

이 변형은 특정 로거에 대한 구성을 적용하는 방법을 보여줍니다 - 예를 들어, foo 로거는 foo 서브 시스템의 모든 이벤트를 mplog-foo.log 파일에 저장하는 특별한 처리기를 갖고 있습니다. 이것은 메인 프로세스의 로깅 시스템이 ( 로깅 이벤트가 작업자 프로세스에서 만들어졌다 하더라도) 메시지를 적절한 대상으로 전달하는 데 사용됩니다.

concurrent.futures.ProcessPoolExecutor 사용하기

concurrent.futures.ProcessPoolExecutor를 사용하여 작업자 프로세스를 시작하려면, 약간 다른 방법으로 큐를 만들어야 합니다.

queue = multiprocessing.Queue(-1)

대신에, 다음을 사용해야 합니다

queue = multiprocessing.Manager().Queue(-1)  # also works with the examples above

그런 다음 작업자 생성을:

workers = []
for i in range(10):
    worker = multiprocessing.Process(target=worker_process,
                                     args=(queue, worker_configurer))
    workers.append(worker)
    worker.start()
for w in workers:
    w.join()

에서 다음과 같이 대체할 수 있습니다 (먼저 concurrent.futures를 임포트 하는 것을 기억하십시오):

with concurrent.futures.ProcessPoolExecutor(max_workers=10) as executor:
    for i in range(10):
        executor.submit(worker_process, queue, worker_configurer)

Deploying Web applications using Gunicorn and uWSGI

When deploying Web applications using Gunicorn [https://gunicorn.org/] or uWSGI [https://uwsgi-docs.readthedocs.io/en/latest/] (or similar), multiple worker processes are created to handle client requests. In such environments, avoid creating file-based handlers directly in your web application. Instead, use a SocketHandler to log from the web application to a listener in a separate process. This can be set up using a process management tool such as Supervisor - see Running a logging socket listener in production for more details.

파일 회전 사용하기

Sometimes you want to let a log file grow to a certain size, then open a new file and log to that. You may want to keep a certain number of these files, and when that many files have been created, rotate the files so that the number of files and the size of the files both remain bounded. For this usage pattern, the logging package provides a RotatingFileHandler:

import glob
import logging
import logging.handlers

LOG_FILENAME = 'logging_rotatingfile_example.out'

# Set up a specific logger with our desired output level
my_logger = logging.getLogger('MyLogger')
my_logger.setLevel(logging.DEBUG)

# Add the log message handler to the logger
handler = logging.handlers.RotatingFileHandler(
              LOG_FILENAME, maxBytes=20, backupCount=5)

my_logger.addHandler(handler)

# Log some messages
for i in range(20):
    my_logger.debug('i = %d' % i)

# See what files are created
logfiles = glob.glob('%s*' % LOG_FILENAME)

for filename in logfiles:
    print(filename)

결과는 6개의 파일이어야 하고, 각기 응용 프로그램에 대한 로그 기록의 일부입니다:

logging_rotatingfile_example.out
logging_rotatingfile_example.out.1
logging_rotatingfile_example.out.2
logging_rotatingfile_example.out.3
logging_rotatingfile_example.out.4
logging_rotatingfile_example.out.5

가장 최근의 파일은 항상 logging_rotatingfile_example.out 이며, 크기 제한에 도달할 때마다 접미사 .1 이 붙은 이름으로 변경됩니다. 기존 백업 파일 각각의 이름이 변경되어 접미사가 증가하고 ( .1 이 .2 가 되는 등) .6 파일이 지워집니다.

분명, 이 예제는 로그 길이를 극단적으로 작게 설정합니다. maxBytes 를 적절한 값으로 설정하고 싶을 겁니다.

대체 포매팅 스타일 사용하기

logging이 파이썬 표준 라이브러리에 추가되었을 때, 가변 내용으로 메시지를 포맷하는 유일한 방법은 %-포매팅 방법을 사용하는 것이었습니다. 그 이후로, 파이썬은 두 개의 새로운 포매팅 접근법을 얻었습니다: string.Template(파이썬 2.4에 추가됨)과 str.format()(파이썬 2.6에 추가됨).

로깅은 (3.2부터) 이 두 가지 추가 포매팅 스타일에 대해 개선된 지원을 제공합니다. Formatter 클래스는 style 이라는 추가적인 키워드 매개 변수를 취하도록 개선되었습니다. 기본값은 '%' 이지만, 다른 두 가지 포매팅 스타일에 해당하는 '{' 및 '$' 를 사용할 수 있습니다. (여러분이 기대하듯이) 이전 버전과의 호환성은 기본적으로 유지되지만, style 매개변수를 명시적으로 지정하면 str.format() 또는 string.Template 과 함께 작동하는 포맷 문자열을 지정할 수 있습니다. 다음은 가능성을 보여주기 위한 예제 콘솔 세션입니다:

>>> import logging
>>> root = logging.getLogger()
>>> root.setLevel(logging.DEBUG)
>>> handler = logging.StreamHandler()
>>> bf = logging.Formatter('{asctime} {name} {levelname:8s} {message}',
...                        style='{')
>>> handler.setFormatter(bf)
>>> root.addHandler(handler)
>>> logger = logging.getLogger('foo.bar')
>>> logger.debug('This is a DEBUG message')
2010-10-28 15:11:55,341 foo.bar DEBUG    This is a DEBUG message
>>> logger.critical('This is a CRITICAL message')
2010-10-28 15:12:11,526 foo.bar CRITICAL This is a CRITICAL message
>>> df = logging.Formatter('$asctime $name ${levelname} $message',
...                        style='$')
>>> handler.setFormatter(df)
>>> logger.debug('This is a DEBUG message')
2010-10-28 15:13:06,924 foo.bar DEBUG This is a DEBUG message
>>> logger.critical('This is a CRITICAL message')
2010-10-28 15:13:11,494 foo.bar CRITICAL This is a CRITICAL message
>>>

로그로 최종 출력하기 위해 로깅 메시지를 포매팅하는 것은 개별 로깅 메시지가 구성되는 방식과 완전히 별개입니다. 개별 메시지에는 다음과 같이 %-포매팅을 사용할 수 있습니다:

>>> logger.error('This is an%s %s %s', 'other,', 'ERROR,', 'message')
2010-10-28 15:19:29,833 foo.bar ERROR This is another, ERROR, message
>>>

로깅 호출(logger.debug(), logger.info() 등)은 실제 로깅 메시지 자체를 위해서는 위치 매개 변수만을 취하고, 키워드 매개 변수는 실제 로깅 호출을 어떻게 다뤄야 하는지를 지정하는 옵션을 결정하는 용도로만 사용됩니다 (예를 들어, 트레이스백 정보를 로그 해야 할지를 가리키는 exc_info 키워드 매개 변수나 로그에 추가되는 문맥 정보를 나타내는 extra 키워드 매개 변수). 그래서 여러분은 str.format() 또는 string.Template 문법을 사용하여 직접 로깅 호출을 할 수 없습니다, 내부적으로 logging 패키지가 %-포매팅을 사용하여 포맷 문자열과 변수 인자를 병합하기 때문입니다. 이전 버전과의 호환성을 유지하는 동안은 이 상황이 바뀌지 않을 것입니다. 기존 코드에 있는 모든 로깅 호출이 %-포맷 문자열을 사용하기 때문입니다.

그러나 {}- 및 $- 포매팅을 사용하여 개별 로그 메시지를 구성하는 방법이 있습니다. 메시지의 경우, 메시지 포맷 문자열로 임의의 객체를 사용할 수 있으며, logging 패키지는 실제 형식 문자열을 얻기 위해 그 객체에 대해 str() 을 호출한다는 것을 상기하십시오. 다음 두 가지 클래스를 고려하십시오:

class BraceMessage:
    def __init__(self, fmt, /, *args, **kwargs):
        self.fmt = fmt
        self.args = args
        self.kwargs = kwargs

    def __str__(self):
        return self.fmt.format(*self.args, **self.kwargs)

class DollarMessage:
    def __init__(self, fmt, /, **kwargs):
        self.fmt = fmt
        self.kwargs = kwargs

    def __str__(self):
        from string import Template
        return Template(self.fmt).substitute(**self.kwargs)

이 중 하나를 포맷 문자열 대신 사용하면, {}- 또는 $-포매팅을 사용하여 포맷된 로그 출력의 “%(message)s”, “{message}” 또는 “$message” 자리에 나타나는 실제 “message” 부분을 만들 수 있습니다. 어떤 것을 로그 하고 싶을 때마다 클래스 이름을 사용하는 것은 다소 꼴사납지만, __(두 개의 밑줄 —- gettext.gettext() 나 그 형제들의 동의어/별칭으로 사용되는 _ 과 혼동하지 마세요)와 같은 별칭을 사용하면 꽤 쓸만합니다.

위의 클래스가 파이썬에 포함되어 있지는 않지만, 아주 쉽게 여러분의 코드에 복사하여 붙여넣을 수 있습니다. 다음과 같이 사용될 수 있습니다 (wherever 라는 모듈에서 선언되었다고 가정합니다):

>>> from wherever import BraceMessage as __
>>> print(__('Message with {0} {name}', 2, name='placeholders'))
Message with 2 placeholders
>>> class Point: pass
...
>>> p = Point()
>>> p.x = 0.5
>>> p.y = 0.5
>>> print(__('Message with coordinates: ({point.x:.2f}, {point.y:.2f})',
...       point=p))
Message with coordinates: (0.50, 0.50)
>>> from wherever import DollarMessage as __
>>> print(__('Message with $num $what', num=2, what='placeholders'))
Message with 2 placeholders
>>>

위의 예제는 print() 를 사용하여 포매팅이 어떻게 작동하는지 보여주고 있지만, 물론 이 접근법으로 실제 로깅 할 때는 logger.debug() 나 그와 유사한 것을 사용해야 합니다.

One thing to note is that you pay no significant performance penalty with this approach: the actual formatting happens not when you make the logging call, but when (and if) the logged message is actually about to be output to a log by a handler. So the only slightly unusual thing which might trip you up is that the parentheses go around the format string and the arguments, not just the format string. That’s because the __ notation is just syntax sugar for a constructor call to one of the XXXMessage classes.

원한다면, LoggerAdapter 를 사용하여 다음 예제와 같이 위와 유사한 효과를 얻을 수 있습니다:

import logging

class Message:
    def __init__(self, fmt, args):
        self.fmt = fmt
        self.args = args

    def __str__(self):
        return self.fmt.format(*self.args)

class StyleAdapter(logging.LoggerAdapter):
    def log(self, level, msg, /, *args, stacklevel=1, **kwargs):
        if self.isEnabledFor(level):
            msg, kwargs = self.process(msg, kwargs)
            self.logger.log(level, Message(msg, args), **kwargs,
                            stacklevel=stacklevel+1)

logger = StyleAdapter(logging.getLogger(__name__))

def main():
    logger.debug('Hello, {}', 'world!')

if __name__ == '__main__':
    logging.basicConfig(level=logging.DEBUG)
    main()

The above script should log the message Hello, world! when run with Python 3.8 or later.

사용자 정의 LogRecord

모든 로깅 이벤트는 LogRecord 인스턴스로 표현됩니다. 이벤트가 로그 되고 로거 수준에 의해 필터링 되지 않으면, LogRecord 가 생성되고 이벤트에 대한 정보로 채워진 다음 해당 로거(와 그 조상들, 계층 상위로의 전파가 비활성화된 지점의 로거까지)의 처리기로 전달됩니다. 파이썬 3.2 이전에는, 이 생성이 일어나는 곳이 두 곳밖에 없었습니다:

Logger.makeRecord(), 이벤트 로깅의 일반적인 프로세스에서 호출됩니다. 인스턴스를 생성하기 위해 LogRecord 를 직접 호출합니다.

makeLogRecord(), LogRecord에 추가될 어트리뷰트를 포함하는 딕셔너리와 함께 호출됩니다. 보통 적절한 딕셔너리가 네트워크를 통해 (예를 들어, SocketHandler 를 통해 피클 형태로, 또는 HTTPHandler 를 통해 JSON 형식으로) 수신될 때 호출됩니다.

이것은 보통 LogRecord 로 특별한 것을 할 필요가 있다면, 다음 중 하나를 해야 한다는 것을 의미합니다.

Logger.makeRecord() 를 재정의하는 자신만의 Logger 서브 클래스를 만들고, 관심 있는 로거의 인스턴스가 만들어지기 전에 setLoggerClass() 를 사용하여 설정하십시오.

로거나 처리기에 Filter를 추가해서 filter() 메서드가 호출될 때 필요한 특별한 조작을 하십시오.

첫 번째 접근법은 여러 라이브러리가 서로 다른 일을 하고 싶어 하는 시나리오에서는 다루기 힘들 것입니다. 각자 자신의 Logger 서브 클래스를 설정하려고 시도할 것이고, 마지막 것이 이기게 될 것입니다.

두 번째 접근법은 많은 경우에 합리적으로 잘 작동하지만, LogRecord 의 특별한 서브 클래스를 사용할 수는 없습니다. 라이브러리 개발자는 로거에 적절한 필터를 설정할 수 있지만, 새로운 로거를 도입할 때마다 이를 수행해야 한다는 것을 기억해야 합니다. 이를 고려하지 않는다면 새 패키지나 모듈을 추가하고 모듈 수준에서 단순히 다음과 같이 합니다:

logger = logging.getLogger(__name__)

이것은 아마도 고려해야 할 많은 것 중 하나일 뿐입니다. 개발자는 자신의 최상위 로거에 첨부된 NullHandler 에도 필터를 추가 할 수 있지만, 응용 프로그램 개발자가 하위 수준 라이브러리 로거에 처리기를 연결하면 호출되지 않습니다 — 그래서 그 처리기로부터의 출력은 라이브러리 개발자의 의도를 반영하지 못합니다.

파이썬 3.2 이상에서는, LogRecord 생성이 사용자가 지정할 수 있는 팩토리를 통해 수행됩니다. 팩토리는 setLogRecordFactory() 로 설정할 수 있고, getLogRecordFactory() 로 조회할 수 있는 콜러블입니다. 팩토리는 LogRecord 생성자와 같은 서명으로 호출되고, 기본 설정은 LogRecord 입니다.

이 방법을 사용하면 사용자 정의 팩토리가 LogRecord 생성의 모든 측면을 제어 할 수 있습니다. 예를 들어, 서브 클래스를 반환하거나, 다음과 같은 방법으로 생성된 레코드에 어트리뷰트를 추가 할 수 있습니다:

old_factory = logging.getLogRecordFactory()

def record_factory(*args, **kwargs):
    record = old_factory(*args, **kwargs)
    record.custom_attribute = 0xdecafbad
    return record

logging.setLogRecordFactory(record_factory)

이 패턴은 서로 다른 라이브러리가 팩토리를 체인으로 연결할 수 있도록 하며, 서로의 어트리뷰트를 덮어쓰거나 의도하지 않게 표준으로 제공된 어트리뷰트를 덮어쓰지 않는 한, 놀랄 일은 없어야 합니다. 그러나 체인의 각 고리는 모든 로깅 작업에 실행시간 오버헤드를 추가하므로, Filter를 사용해서 원하는 결과를 얻을 수 없을 때만 이 기법을 사용해야 합니다.

Subclassing QueueHandler and QueueListener- a ZeroMQ example

Subclass QueueHandler

QueueHandler 서브 클래스를 사용하여 다른 유형의 큐에 메시지를 보낼 수 있습니다, 예를 들어 ZeroMQ ‘publish’ 소켓. 아래 예제에서, 소켓은 별도로 생성되어 처리기로 (‘queue’로) 전달됩니다:

import zmq   # using pyzmq, the Python binding for ZeroMQ
import json  # for serializing records portably

ctx = zmq.Context()
sock = zmq.Socket(ctx, zmq.PUB)  # or zmq.PUSH, or other suitable value
sock.bind('tcp://*:5556')        # or wherever

class ZeroMQSocketHandler(QueueHandler):
    def enqueue(self, record):
        self.queue.send_json(record.__dict__)

handler = ZeroMQSocketHandler(sock)

물론 구성하는 다른 방법이 있습니다. 예를 들어 처리기가 소켓을 만드는데 필요한 데이터를 전달하는 것입니다:

class ZeroMQSocketHandler(QueueHandler):
    def __init__(self, uri, socktype=zmq.PUB, ctx=None):
        self.ctx = ctx or zmq.Context()
        socket = zmq.Socket(self.ctx, socktype)
        socket.bind(uri)
        super().__init__(socket)

    def enqueue(self, record):
        self.queue.send_json(record.__dict__)

    def close(self):
        self.queue.close()

Subclass QueueListener

다른 유형의 큐에서 메시지를 받기 위해 QueueListener 의 서브 클래스를 만들 수도 있습니다, 예를 들어 ZeroMQ ‘subscribe’ 소켓. 다음은 그 예입니다:

class ZeroMQSocketListener(QueueListener):
    def __init__(self, uri, /, *handlers, **kwargs):
        self.ctx = kwargs.get('ctx') or zmq.Context()
        socket = zmq.Socket(self.ctx, zmq.SUB)
        socket.setsockopt_string(zmq.SUBSCRIBE, '')  # subscribe to everything
        socket.connect(uri)
        super().__init__(socket, *handlers, **kwargs)

    def dequeue(self):
        msg = self.queue.recv_json()
        return logging.makeLogRecord(msg)

Subclassing QueueHandler and QueueListener- a pynng example

In a similar way to the above section, we can implement a listener and handler using pynng [https://pypi.org/project/pynng/], which is a Python binding to NNG [https://nng.nanomsg.org/], billed as a spiritual successor to ZeroMQ. The following snippets illustrate – you can test them in an environment which has pynng installed. Just for variety, we present the listener first.

Subclass QueueListener

# listener.py
import json
import logging
import logging.handlers

import pynng

DEFAULT_ADDR = "tcp://localhost:13232"

interrupted = False

class NNGSocketListener(logging.handlers.QueueListener):

    def __init__(self, uri, /, *handlers, **kwargs):
        # Have a timeout for interruptability, and open a
        # subscriber socket
        socket = pynng.Sub0(listen=uri, recv_timeout=500)
        # The b'' subscription matches all topics
        topics = kwargs.pop('topics', None) or b''
        socket.subscribe(topics)
        # We treat the socket as a queue
        super().__init__(socket, *handlers, **kwargs)

    def dequeue(self, block):
        data = None
        # Keep looping while not interrupted and no data received over the
        # socket
        while not interrupted:
            try:
                data = self.queue.recv(block=block)
                break
            except pynng.Timeout:
                pass
            except pynng.Closed:  # sometimes happens when you hit Ctrl-C
                break
        if data is None:
            return None
        # Get the logging event sent from a publisher
        event = json.loads(data.decode('utf-8'))
        return logging.makeLogRecord(event)

    def enqueue_sentinel(self):
        # Not used in this implementation, as the socket isn't really a
        # queue
        pass

logging.getLogger('pynng').propagate = False
listener = NNGSocketListener(DEFAULT_ADDR, logging.StreamHandler(), topics=b'')
listener.start()
print('Press Ctrl-C to stop.')
try:
    while True:
        pass
except KeyboardInterrupt:
    interrupted = True
finally:
    listener.stop()

Subclass QueueHandler

# sender.py
import json
import logging
import logging.handlers
import time
import random

import pynng

DEFAULT_ADDR = "tcp://localhost:13232"

class NNGSocketHandler(logging.handlers.QueueHandler):

    def __init__(self, uri):
        socket = pynng.Pub0(dial=uri, send_timeout=500)
        super().__init__(socket)

    def enqueue(self, record):
        # Send the record as UTF-8 encoded JSON
        d = dict(record.__dict__)
        data = json.dumps(d)
        self.queue.send(data.encode('utf-8'))

    def close(self):
        self.queue.close()

logging.getLogger('pynng').propagate = False
handler = NNGSocketHandler(DEFAULT_ADDR)
# Make sure the process ID is in the output
logging.basicConfig(level=logging.DEBUG,
                    handlers=[logging.StreamHandler(), handler],
                    format='%(levelname)-8s %(name)10s %(process)6s %(message)s')
levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
          logging.CRITICAL)
logger_names = ('myapp', 'myapp.lib1', 'myapp.lib2')
msgno = 1
while True:
    # Just randomly select some loggers and levels and log away
    level = random.choice(levels)
    logger = logging.getLogger(random.choice(logger_names))
    logger.log(level, 'Message no. %5d' % msgno)
    msgno += 1
    delay = random.random() * 2 + 0.5
    time.sleep(delay)

You can run the above two snippets in separate command shells. If we run the listener in one shell and run the sender in two separate shells, we should see something like the following. In the first sender shell:

$ python sender.py
DEBUG         myapp    613 Message no.     1
WARNING  myapp.lib2    613 Message no.     2
CRITICAL myapp.lib2    613 Message no.     3
WARNING  myapp.lib2    613 Message no.     4
CRITICAL myapp.lib1    613 Message no.     5
DEBUG         myapp    613 Message no.     6
CRITICAL myapp.lib1    613 Message no.     7
INFO     myapp.lib1    613 Message no.     8
(and so on)

In the second sender shell:

$ python sender.py
INFO     myapp.lib2    657 Message no.     1
CRITICAL myapp.lib2    657 Message no.     2
CRITICAL      myapp    657 Message no.     3
CRITICAL myapp.lib1    657 Message no.     4
INFO     myapp.lib1    657 Message no.     5
WARNING  myapp.lib2    657 Message no.     6
CRITICAL      myapp    657 Message no.     7
DEBUG    myapp.lib1    657 Message no.     8
(and so on)

In the listener shell:

$ python listener.py
Press Ctrl-C to stop.
DEBUG         myapp    613 Message no.     1
WARNING  myapp.lib2    613 Message no.     2
INFO     myapp.lib2    657 Message no.     1
CRITICAL myapp.lib2    613 Message no.     3
CRITICAL myapp.lib2    657 Message no.     2
CRITICAL      myapp    657 Message no.     3
WARNING  myapp.lib2    613 Message no.     4
CRITICAL myapp.lib1    613 Message no.     5
CRITICAL myapp.lib1    657 Message no.     4
INFO     myapp.lib1    657 Message no.     5
DEBUG         myapp    613 Message no.     6
WARNING  myapp.lib2    657 Message no.     6
CRITICAL      myapp    657 Message no.     7
CRITICAL myapp.lib1    613 Message no.     7
INFO     myapp.lib1    613 Message no.     8
DEBUG    myapp.lib1    657 Message no.     8
(and so on)

As you can see, the logging from the two sender processes is interleaved in the listener’s output.

딕셔너리 기반 구성의 예

다음은 로깅 구성 딕셔너리의 예입니다 - 장고 프로젝트 설명서 [https://docs.djangoproject.com/en/stable/topics/logging/#configuring-logging] 에서 가져왔습니다. 이 딕셔너리를 dictConfig() 로 전달하여 구성을 적용합니다:

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'verbose': {
            'format': '{levelname} {asctime} {module} {process:d} {thread:d} {message}',
            'style': '{',
        },
        'simple': {
            'format': '{levelname} {message}',
            'style': '{',
        },
    },
    'filters': {
        'special': {
            '()': 'project.logging.SpecialFilter',
            'foo': 'bar',
        },
    },
    'handlers': {
        'console': {
            'level': 'INFO',
            'class': 'logging.StreamHandler',
            'formatter': 'simple',
        },
        'mail_admins': {
            'level': 'ERROR',
            'class': 'django.utils.log.AdminEmailHandler',
            'filters': ['special']
        }
    },
    'loggers': {
        'django': {
            'handlers': ['console'],
            'propagate': True,
        },
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': False,
        },
        'myproject.custom': {
            'handlers': ['console', 'mail_admins'],
            'level': 'INFO',
            'filters': ['special']
        }
    }
}

이 구성에 대한 더 자세한 정보는 장고 설명서의 관련 섹션 [https://docs.djangoproject.com/en/stable/topics/logging/#configuring-logging] 을 참조하세요.

rotator와 namer를 사용해서 로그 회전 처리하기

An example of how you can define a namer and rotator is given in the following runnable script, which shows gzip compression of the log file:

import gzip
import logging
import logging.handlers
import os
import shutil

def namer(name):
    return name + ".gz"

def rotator(source, dest):
    with open(source, 'rb') as f_in:
        with gzip.open(dest, 'wb') as f_out:
            shutil.copyfileobj(f_in, f_out)
    os.remove(source)

rh = logging.handlers.RotatingFileHandler('rotated.log', maxBytes=128, backupCount=5)
rh.rotator = rotator
rh.namer = namer

root = logging.getLogger()
root.setLevel(logging.INFO)
root.addHandler(rh)
f = logging.Formatter('%(asctime)s %(message)s')
rh.setFormatter(f)
for i in range(1000):
    root.info(f'Message no. {i + 1}')

After running this, you will see six new files, five of which are compressed:

$ ls rotated.log*
rotated.log       rotated.log.2.gz  rotated.log.4.gz
rotated.log.1.gz  rotated.log.3.gz  rotated.log.5.gz
$ zcat rotated.log.1.gz
2023-01-20 02:28:17,767 Message no. 996
2023-01-20 02:28:17,767 Message no. 997
2023-01-20 02:28:17,767 Message no. 998

좀 더 정교한 multiprocessing 예제

다음 동작하는 예제에서는 구성 파일을 사용하여 로깅을 multiprocessing과 함께 사용하는 방법을 보여줍니다. 구성은 매우 간단하지만, 실제 multiprocessing 시나리오에서 더 복잡한 구성을 구현할 수 있음을 예시합니다.

이 예에서, 주 프로세스는 리스너 프로세스와 몇 개의 작업자 프로세스를 생성합니다. 주 프로세스, 리스너 및 작업자를 위한 세 가지 구성이 있습니다 (모든 작업자는 같은 구성을 공유합니다). 주 프로세스에서의 로깅, 작업자가 QueueHandler에 로그 하는 방법, 그리고 리스너가 QueueListener 및 더욱 복잡한 로깅 구성을 구현하고 큐를 통해 수신한 이벤트를 구성에서 지정된 처리기로 전달하도록 배치하는 는 방법을 볼 수 있습니다. 이러한 구성은 설명을 위한 것이지만, 이 예제를 여러분 자신의 시나리오에 적용할 수 있어야 합니다.

스크립트는 다음과 같습니다 - 독스트링과 주석이 어떻게 작동하는지 잘 설명하기를 바랍니다:

import logging
import logging.config
import logging.handlers
from multiprocessing import Process, Queue, Event, current_process
import os
import random
import time

class MyHandler:
    """
    A simple handler for logging events. It runs in the listener process and
    dispatches events to loggers based on the name in the received record,
    which then get dispatched, by the logging system, to the handlers
    configured for those loggers.
    """

    def handle(self, record):
        if record.name == "root":
            logger = logging.getLogger()
        else:
            logger = logging.getLogger(record.name)

        if logger.isEnabledFor(record.levelno):
            # The process name is transformed just to show that it's the listener
            # doing the logging to files and console
            record.processName = '%s (for %s)' % (current_process().name, record.processName)
            logger.handle(record)

def listener_process(q, stop_event, config):
    """
    This could be done in the main process, but is just done in a separate
    process for illustrative purposes.

    This initialises logging according to the specified configuration,
    starts the listener and waits for the main process to signal completion
    via the event. The listener is then stopped, and the process exits.
    """
    logging.config.dictConfig(config)
    listener = logging.handlers.QueueListener(q, MyHandler())
    listener.start()
    if os.name == 'posix':
        # On POSIX, the setup logger will have been configured in the
        # parent process, but should have been disabled following the
        # dictConfig call.
        # On Windows, since fork isn't used, the setup logger won't
        # exist in the child, so it would be created and the message
        # would appear - hence the "if posix" clause.
        logger = logging.getLogger('setup')
        logger.critical('Should not appear, because of disabled logger ...')
    stop_event.wait()
    listener.stop()

def worker_process(config):
    """
    A number of these are spawned for the purpose of illustration. In
    practice, they could be a heterogeneous bunch of processes rather than
    ones which are identical to each other.

    This initialises logging according to the specified configuration,
    and logs a hundred messages with random levels to randomly selected
    loggers.

    A small sleep is added to allow other processes a chance to run. This
    is not strictly needed, but it mixes the output from the different
    processes a bit more than if it's left out.
    """
    logging.config.dictConfig(config)
    levels = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
              logging.CRITICAL]
    loggers = ['foo', 'foo.bar', 'foo.bar.baz',
               'spam', 'spam.ham', 'spam.ham.eggs']
    if os.name == 'posix':
        # On POSIX, the setup logger will have been configured in the
        # parent process, but should have been disabled following the
        # dictConfig call.
        # On Windows, since fork isn't used, the setup logger won't
        # exist in the child, so it would be created and the message
        # would appear - hence the "if posix" clause.
        logger = logging.getLogger('setup')
        logger.critical('Should not appear, because of disabled logger ...')
    for i in range(100):
        lvl = random.choice(levels)
        logger = logging.getLogger(random.choice(loggers))
        logger.log(lvl, 'Message no. %d', i)
        time.sleep(0.01)

def main():
    q = Queue()
    # The main process gets a simple configuration which prints to the console.
    config_initial = {
        'version': 1,
        'handlers': {
            'console': {
                'class': 'logging.StreamHandler',
                'level': 'INFO'
            }
        },
        'root': {
            'handlers': ['console'],
            'level': 'DEBUG'
        }
    }
    # The worker process configuration is just a QueueHandler attached to the
    # root logger, which allows all messages to be sent to the queue.
    # We disable existing loggers to disable the "setup" logger used in the
    # parent process. This is needed on POSIX because the logger will
    # be there in the child following a fork().
    config_worker = {
        'version': 1,
        'disable_existing_loggers': True,
        'handlers': {
            'queue': {
                'class': 'logging.handlers.QueueHandler',
                'queue': q
            }
        },
        'root': {
            'handlers': ['queue'],
            'level': 'DEBUG'
        }
    }
    # The listener process configuration shows that the full flexibility of
    # logging configuration is available to dispatch events to handlers however
    # you want.
    # We disable existing loggers to disable the "setup" logger used in the
    # parent process. This is needed on POSIX because the logger will
    # be there in the child following a fork().
    config_listener = {
        'version': 1,
        'disable_existing_loggers': True,
        'formatters': {
            'detailed': {
                'class': 'logging.Formatter',
                'format': '%(asctime)s %(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
            },
            'simple': {
                'class': 'logging.Formatter',
                'format': '%(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
            }
        },
        'handlers': {
            'console': {
                'class': 'logging.StreamHandler',
                'formatter': 'simple',
                'level': 'INFO'
            },
            'file': {
                'class': 'logging.FileHandler',
                'filename': 'mplog.log',
                'mode': 'w',
                'formatter': 'detailed'
            },
            'foofile': {
                'class': 'logging.FileHandler',
                'filename': 'mplog-foo.log',
                'mode': 'w',
                'formatter': 'detailed'
            },
            'errors': {
                'class': 'logging.FileHandler',
                'filename': 'mplog-errors.log',
                'mode': 'w',
                'formatter': 'detailed',
                'level': 'ERROR'
            }
        },
        'loggers': {
            'foo': {
                'handlers': ['foofile']
            }
        },
        'root': {
            'handlers': ['console', 'file', 'errors'],
            'level': 'DEBUG'
        }
    }
    # Log some initial events, just to show that logging in the parent works
    # normally.
    logging.config.dictConfig(config_initial)
    logger = logging.getLogger('setup')
    logger.info('About to create workers ...')
    workers = []
    for i in range(5):
        wp = Process(target=worker_process, name='worker %d' % (i + 1),
                     args=(config_worker,))
        workers.append(wp)
        wp.start()
        logger.info('Started worker: %s', wp.name)
    logger.info('About to create listener ...')
    stop_event = Event()
    lp = Process(target=listener_process, name='listener',
                 args=(q, stop_event, config_listener))
    lp.start()
    logger.info('Started listener')
    # We now hang around for the workers to finish their work.
    for wp in workers:
        wp.join()
    # Workers all done, listening can now stop.
    # Logging in the parent still works normally.
    logger.info('Telling listener to stop ...')
    stop_event.set()
    lp.join()
    logger.info('All done.')

if __name__ == '__main__':
    main()

SysLogHandler로 전송된 메시지에 BOM 삽입하기

RFC 5424 [https://datatracker.ietf.org/doc/html/rfc5424.html] 는 유니코드 메시지가 다음 구조를 갖는 바이트들로 syslog 데몬에 전송되어야 함을 요구합니다: 선택적인 순수 ASCII 구성 요소, 그 뒤를 이어 UTF-8 바이트 순서 표식 (BOM), 그 뒤를 이어 UTF-8으로 인코딩된 유니코드. (이 규격의 관련 절 [https://datatracker.ietf.org/doc/html/rfc5424.html#section-6] 을 참조하십시오.)

파이썬 3.1에서, BOM을 메시지에 삽입하는 코드가 SysLogHandler 에 추가되었지만, 유감스럽게도, BOM이 메시지의 시작 부분에 나타나서 그 앞에 순수 ASCII 구성 요소를 허락하지 않도록 잘못 구현되었습니다.

이 동작이 잘못됨에 따라, 잘못된 BOM 삽입 코드가 파이썬 3.2.4 이상에서 제거되었습니다. 그러나, 올바른 코드로 대체되지는 않았고, BOM을 포함하고, 그 앞에 순수 ASCII 시퀀스, 그 뒤에 UTF-8으로 인코딩된 임의의 유니코드로 구성된 RFC 5424 [https://datatracker.ietf.org/doc/html/rfc5424.html]-호환 메시지를 생성하려는 경우 다음과 같이 해야 합니다:

Formatter 인스턴스를 SysLogHandler 인스턴스에 다음과 같은 포맷 문자열과 함께 첨부하십시오:

'ASCII section\ufeffUnicode section'

유니코드 코드 포인트 U+FEFF는, UTF-8을 사용하여 인코딩될 때, UTF-8 BOM으로 인코딩됩니다 – 바이트열 b'\xef\xbb\xbf'.

ASCII section을 원하는 자리 표시기로 바꾸십시오. 그러나 치환 후 나타나는 데이터가 항상 ASCII임미 보장되어야 합니다 (그렇게 되면, UTF-8 인코딩 이후에는 변경되지 않은 채로 유지됩니다).

Unidcode section을 원하는 자리 표시기로 바꾸십시오; 치환 후 나타나는 데이터에 ASCII 범위를 벗어나는 문자가 포함되어 있어도 괜찮습니다 – UTF-8을 사용하여 인코딩됩니다.

포맷된 된 메시지는 SysLogHandler 에 의해 UTF-8 인코딩을 사용하여 인코딩*됩니다*. 위의 규칙을 따르는 경우, RFC 5424 [https://datatracker.ietf.org/doc/html/rfc5424.html]-호환 메시지를 생성할 수 있어야 합니다. 그렇지 않으면, logging이 불평하지 않을 수도 있지만, 메시지가 RFC 5424와 호환되지 않고 syslog 데몬이 불평 할 수 있습니다.

구조적 로깅 구현

대부분의 로깅 메시지는 사람이 읽을 수 있도록 만들어졌기 때문에 쉽게 기계에서 파싱 할 수 없지만, 프로그램에서 (복잡한 정규식을 사용하지 않고도) 구문 분석할 수 있는 구조화된 포맷으로 메시지를 출력하려는 상황이 있을 수 있습니다. 이것은 logging 패키지를 사용하여 쉽게 달성 할 수 있습니다. 이것이 달성될 수 있는 여러 가지 방법이 있지만, 다음은 JSON을 사용하여 기계가 파싱할 수 있는 방식으로 이벤트를 직렬화하는 간단한 접근법입니다:

import json
import logging

class StructuredMessage:
    def __init__(self, message, /, **kwargs):
        self.message = message
        self.kwargs = kwargs

    def __str__(self):
        return '%s >>> %s' % (self.message, json.dumps(self.kwargs))

_ = StructuredMessage   # optional, to improve readability

logging.basicConfig(level=logging.INFO, format='%(message)s')
logging.info(_('message 1', foo='bar', bar='baz', num=123, fnum=123.456))

위의 스크립트가 실행되면 다음과 같이 인쇄됩니다:

message 1 >>> {"fnum": 123.456, "num": 123, "bar": "baz", "foo": "bar"}

항목의 순서는 사용된 파이썬 버전에 따라 다를 수 있습니다.

좀 더 특별한 처리가 필요한 경우, 다음 예제와 같이 사용자 정의 JSON 인코더를 사용할 수 있습니다:

import json
import logging

class Encoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, set):
            return tuple(o)
        elif isinstance(o, str):
            return o.encode('unicode_escape').decode('ascii')
        return super().default(o)

class StructuredMessage:
    def __init__(self, message, /, **kwargs):
        self.message = message
        self.kwargs = kwargs

    def __str__(self):
        s = Encoder().encode(self.kwargs)
        return '%s >>> %s' % (self.message, s)

_ = StructuredMessage   # optional, to improve readability

def main():
    logging.basicConfig(level=logging.INFO, format='%(message)s')
    logging.info(_('message 1', set_value={1, 2, 3}, snowman='\u2603'))

if __name__ == '__main__':
    main()

위의 스크립트를 실행하면 다음과 같이 인쇄합니다:

message 1 >>> {"snowman": "\u2603", "set_value": [1, 2, 3]}

항목의 순서는 사용된 파이썬 버전에 따라 다를 수 있습니다.

dictConfig()로 처리기를 사용자 정의하기

특정 상황에서 로깅 처리기를 사용자 정의하고 싶을 때가 있고, dictConfig()를 사용하고 있다면 서브 클래스를 만들지 않고도 이 작업을 수행 할 수 있습니다. 예를 들어, 로그 파일의 소유권을 설정하고 싶다고 합시다. POSIX에서, shutil.chown() 을 사용하면 쉽게 할 수 있지만, 표준 라이브러리의 파일 처리기는 내장된 지원을 제공하지 않습니다. 다음과 같은 일반 함수를 사용하여 처리기 생성을 사용자 정의 할 수 있습니다:

def owned_file_handler(filename, mode='a', encoding=None, owner=None):
    if owner:
        if not os.path.exists(filename):
            open(filename, 'a').close()
        shutil.chown(filename, *owner)
    return logging.FileHandler(filename, mode, encoding)

그런 다음, dictConfig() 에 전달되는 로깅 구성에서, 이 함수를 호출하여 로깅 처리기를 생성하도록 지정할 수 있습니다:

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'default': {
            'format': '%(asctime)s %(levelname)s %(name)s %(message)s'
        },
    },
    'handlers': {
        'file':{
            # The values below are popped from this dictionary and
            # used to create the handler, set the handler's level and
            # its formatter.
            '()': owned_file_handler,
            'level':'DEBUG',
            'formatter': 'default',
            # The values below are passed to the handler creator callable
            # as keyword arguments.
            'owner': ['pulse', 'pulse'],
            'filename': 'chowntest.log',
            'mode': 'w',
            'encoding': 'utf-8',
        },
    },
    'root': {
        'handlers': ['file'],
        'level': 'DEBUG',
    },
}

이 예제에서는 단지 예를 들기 위해 pulse 라는 사용자와 그룹을 사용하여 소유권을 설정합니다. 작동하는 스크립트 chowntest.py 로 정리하면:

import logging, logging.config, os, shutil

def owned_file_handler(filename, mode='a', encoding=None, owner=None):
    if owner:
        if not os.path.exists(filename):
            open(filename, 'a').close()
        shutil.chown(filename, *owner)
    return logging.FileHandler(filename, mode, encoding)

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'default': {
            'format': '%(asctime)s %(levelname)s %(name)s %(message)s'
        },
    },
    'handlers': {
        'file':{
            # The values below are popped from this dictionary and
            # used to create the handler, set the handler's level and
            # its formatter.
            '()': owned_file_handler,
            'level':'DEBUG',
            'formatter': 'default',
            # The values below are passed to the handler creator callable
            # as keyword arguments.
            'owner': ['pulse', 'pulse'],
            'filename': 'chowntest.log',
            'mode': 'w',
            'encoding': 'utf-8',
        },
    },
    'root': {
        'handlers': ['file'],
        'level': 'DEBUG',
    },
}

logging.config.dictConfig(LOGGING)
logger = logging.getLogger('mylogger')
logger.debug('A debug message')

이것을 실행하기 위해서는, 아마도 root 로 실행해야 할 것입니다:

$ sudo python3.3 chowntest.py
$ cat chowntest.log
2013-11-05 09:34:51,128 DEBUG mylogger A debug message
$ ls -l chowntest.log
-rw-r--r-- 1 pulse pulse 55 2013-11-05 09:34 chowntest.log

이 예제는 shutil.chown() 이 등장한 파이썬 3.3을 사용합니다. 이 접근법은 dictConfig()를 지원하는 모든 파이썬 버전에서 작동합니다 - 파이썬 2.7, 3.2 이상. 3.3 이전 버전의 경우, (예를 들어) os.chown() 을 사용하여 실제 소유권 변경을 구현해야 합니다.

실제로는, 처리기 생성 함수가 프로젝트 어딘가에 있는 유틸리티 모듈에 있을 수 있습니다. 구성에 있는 다음과 같은 줄 대신:

'()': owned_file_handler,

예를 들면 이렇게 쓸 수 있습니다:

'()': 'ext://project.util.owned_file_handler',

여기서 project.util 은 함수가 있는 패키지의 실제 이름으로 바꿀 수 있습니다. 위의 작업 스크립트에서 'ext://__main__.owned_file_handler' 를 사용해도 됩니다. 여기서, 실제 콜러블은 ext:// 스펙으로부터 dictConfig() 에 의해 결정됩니다.

이 예제는 희망하건대 다른 형태의 파일 변경을 - 예를 들어 특정 POSIX 권한 비트 설정 - 같은 방법으로 (os.chmod() 를 사용해서) 구현하는 방법도 알려줍니다.

물론 이 접근법은 FileHandler 이외의 처리기 유형으로도 확장될 수 있습니다 - 예를 들어, 회전 파일 처리기 중 하나 또는 다른 유형의 처리기 모두.

응용 프로그램 전체에서 특정 포맷 스타일 사용하기

파이썬 3.2에서, Formatter 는 style 키워드 매개변수를 얻었는데, 이전 버전과의 호환성을 위해 % 를 기본값으로 사용하면서 { 또는 $ 를 지정하면 str.format() 과 string.Template 에 의해 지원되는 포매팅 접근법을 사용할 수 있도록 합니다. 이것은 로그 되는 최종 출력으로 로깅 메시지를 포매팅하는 것과 관계된 것이고, 개별 로깅 메시지가 만들어지는 방법과는 무관함에 주의하십시오.

Logging calls (debug(), info() etc.) only take positional parameters for the actual logging message itself, with keyword parameters used only for determining options for how to handle the logging call (e.g. the exc_info keyword parameter to indicate that traceback information should be logged, or the extra keyword parameter to indicate additional contextual information to be added to the log). So you cannot directly make logging calls using str.format() or string.Template syntax, because internally the logging package uses %-formatting to merge the format string and the variable arguments. There would be no changing this while preserving backward compatibility, since all logging calls which are out there in existing code will be using %-format strings.

포맷 스타일을 특정 로거와 연관시키는 제안이 있었지만, 이전 버전과의 호환성 문제가 있는데, 기존 코드가 그 로거 이름으로 %-포매팅을 사용할 수 있기 때문입니다.

제삼자 라이브러리와 여러분의 코드 간에 상호 운용이 가능하도록 로깅 하려면, 개별 로깅 호출 수준에서 포매팅을 결정해야 합니다. 이렇게 할 때 대체 포매팅 스타일을 수용 할 수 있는 몇 가지 길이 열립니다.

LogRecord 팩토리 사용

파이썬 3.2에서, 위에서 언급 한 Formatter 변경 사항과 함께, logging 패키지는 setLogRecordFactory() 함수를 사용하여 사용자가 자신의 LogRecord 서브 클래스를 설정할 수 있는 기능을 얻었습니다. 이것을 사용하면, 원하는 일을 하도록 getMessage() 메서드를 재정의하는 여러분 자신의 LogRecord 서브 클래스를 설정할 수 있습니다. 이 메서드의 베이스 클래스 구현이 msg % args 포매팅이 일어나는 곳이며, 여러분이 대체 포매팅으로 치환할 수 있는 곳입니다; 그러나, 모든 포매팅 스타일을 지원하면서 다른 코드와의 상호 운용성을 보장하기 위해 %-포매팅을 기본값으로 사용하도록 주의해야 합니다. 또한, 베이스 구현과 마찬가지로 str(self.msg) 를 호출하도록 주의해야 합니다.

자세한 정보는 setLogRecordFactory()와 LogRecord 에 대한 레퍼런스 설명서를 참조하십시오.

사용자 정의 메시지 객체 사용

{}- 및 $-포매팅을 사용하여 개별 로그 메시지를 작성할 수 있는 또 다른, 아마도 더 간단한 방법이 있습니다. (임의의 객체를 메시지로 사용하기에서) 로깅 할 때 임의의 객체를 메시지 포맷 문자열로 사용할 수 있고, logging 패키지는 그 객체에 대해 str() 을 호출하여 실제 형식 문자열을 얻는다고 했던 것을 기억하실 수 있을 겁니다. 다음 두 클래스를 생각해봅시다:

class BraceMessage:
    def __init__(self, fmt, /, *args, **kwargs):
        self.fmt = fmt
        self.args = args
        self.kwargs = kwargs

    def __str__(self):
        return self.fmt.format(*self.args, **self.kwargs)

class DollarMessage:
    def __init__(self, fmt, /, **kwargs):
        self.fmt = fmt
        self.kwargs = kwargs

    def __str__(self):
        from string import Template
        return Template(self.fmt).substitute(**self.kwargs)

이 중 하나를 포맷 문자열 대신 사용하면, {}- 또는 $-포매팅을 사용하여 포맷된 로그 출력의 “%(message)s”, “{message}” 또는 “$message” 자리에 나타나는 실제 “message” 부분을 만들 수 있습니다. 어떤 것을 로그 하고 싶을 때마다 클래스 이름을 사용하는 것이 다소 꼴사납다면, 메시지에 M 이나 _ 과 같은 별칭을 사용해서 더 쓸만하게 만들 수 있습니다 (또는 지역화에 _ 를 사용하고 있다면, 아마도 __).

이 접근법의 예가 아래에 나와 있습니다. 먼저, str.format() 를 사용하는 포매팅입니다:

>>> __ = BraceMessage
>>> print(__('Message with {0} {1}', 2, 'placeholders'))
Message with 2 placeholders
>>> class Point: pass
...
>>> p = Point()
>>> p.x = 0.5
>>> p.y = 0.5
>>> print(__('Message with coordinates: ({point.x:.2f}, {point.y:.2f})', point=p))
Message with coordinates: (0.50, 0.50)

두 번째로, string.Template 를 사용하는 포매팅입니다:

>>> __ = DollarMessage
>>> print(__('Message with $num $what', num=2, what='placeholders'))
Message with 2 placeholders
>>>

One thing to note is that you pay no significant performance penalty with this approach: the actual formatting happens not when you make the logging call, but when (and if) the logged message is actually about to be output to a log by a handler. So the only slightly unusual thing which might trip you up is that the parentheses go around the format string and the arguments, not just the format string. That’s because the __ notation is just syntax sugar for a constructor call to one of the XXXMessage classes shown above.

dictConfig()로 필터 구성하기

dictConfig() 를 사용하여 필터를 구성할 수 있습니다. 하지만 처음에는 어떻게 해야 할지 명확하지 않을 수 있습니다 (그래서 이 조리법을 제공합니다). Filter 가 표준 라이브러리에 포함된 유일한 필터 클래스이고, 많은 요구 사항을 충족시키지는 않을 것이기 때문에 (오직 베이스 클래스로 제공됩니다), 일반적으로 filter() 메서드를 재정의하는 여러분 자신의 Filter 서브 클래스를 정의할 필요가 있습니다. 이렇게 하려면, 필터를 생성하는 데 사용될 콜러블을 필터의 구성 딕셔너리에 () 키로 지정하십시오 (클래스가 가장 분명하지만 Filter 인스턴스를 반환하는 콜러블은 모두 가능합니다). 다음은 완전한 예입니다:

import logging
import logging.config
import sys

class MyFilter(logging.Filter):
    def __init__(self, param=None):
        self.param = param

    def filter(self, record):
        if self.param is None:
            allow = True
        else:
            allow = self.param not in record.msg
        if allow:
            record.msg = 'changed: ' + record.msg
        return allow

LOGGING = {
    'version': 1,
    'filters': {
        'myfilter': {
            '()': MyFilter,
            'param': 'noshow',
        }
    },
    'handlers': {
        'console': {
            'class': 'logging.StreamHandler',
            'filters': ['myfilter']
        }
    },
    'root': {
        'level': 'DEBUG',
        'handlers': ['console']
    },
}

if __name__ == '__main__':
    logging.config.dictConfig(LOGGING)
    logging.debug('hello')
    logging.debug('hello - noshow')

이 예제는 인스턴스를 만드는 콜러블로 키워드 매개 변수 형식으로 구성 데이터를 전달하는 방법을 보여줍니다. 실행하면, 위의 스크립트는 다음을 인쇄합니다:

changed: hello

필터가 구성된 대로 작동하고 있음을 보여줍니다.

주목해야 할 몇 가지 추가 사항:

구성에서 직접 참조할 수 없는 경우 (예를 들어, 다른 모듈에 있고 구성 딕셔너리가 있는 곳에서 직접 임포트 할 수 없는 경우), 외부 객체에 대한 액세스 에 설명된 대로 ext://... 형식을 사용할 수 있습니다. 예를 들어, 위의 예에서 MyFilter 대신 'ext://__main__.MyFilter' 를 사용할 수 있습니다.

필터뿐만 아니라, 이 기술을 사용자 정의 처리기 및 포매터를 구성하는데 사용할 수도 있습니다. logging이 구성에서 사용자 정의 객체를 어떻게 지원하는지에 대한 더 많은 정보는 사용자 정의 객체 를 보시고, 위의 다른 요리책 조리법 dictConfig()로 처리기를 사용자 정의하기 도 보십시오.

사용자 정의된 예외 포매팅

예외 포매팅을 사용자 정의하고 싶을 때가 있습니다 - 논쟁의 여지는 있지만, 예외 정보가 포함된 경우에도 이벤트 당 정확히 한 줄이 기록되기 원한다고 합시다. 다음 예제처럼, 사용자 정의 포매터 클래스를 사용할 수 있습니다:

import logging

class OneLineExceptionFormatter(logging.Formatter):
    def formatException(self, exc_info):
        """
        Format an exception so that it prints on a single line.
        """
        result = super().formatException(exc_info)
        return repr(result)  # or format into one line however you want to

    def format(self, record):
        s = super().format(record)
        if record.exc_text:
            s = s.replace('\n', '') + '|'
        return s

def configure_logging():
    fh = logging.FileHandler('output.txt', 'w')
    f = OneLineExceptionFormatter('%(asctime)s|%(levelname)s|%(message)s|',
                                  '%d/%m/%Y %H:%M:%S')
    fh.setFormatter(f)
    root = logging.getLogger()
    root.setLevel(logging.DEBUG)
    root.addHandler(fh)

def main():
    configure_logging()
    logging.info('Sample message')
    try:
        x = 1 / 0
    except ZeroDivisionError as e:
        logging.exception('ZeroDivisionError: %s', e)

if __name__ == '__main__':
    main()

실행하면, 정확하게 두 줄의 파일이 생성됩니다:

28/01/2015 07:21:23|INFO|Sample message|
28/01/2015 07:21:23|ERROR|ZeroDivisionError: division by zero|'Traceback (most recent call last):\n  File "logtest7.py", line 30, in main\n    x = 1 / 0\nZeroDivisionError: division by zero'|

위의 처리는 단순하지만, 예외 정보를 원하는 대로 포맷하는 방법을 알려줍니다. traceback 모듈은 더욱 전문화된 요구에 도움이 될 수 있습니다.

로깅 메시지 말하기

로깅 메시지를 보여주는 대신 들려주는 것이 바람직한 상황이 있을 수 있습니다. 여러분의 시스템에 텍스트-음성 변환 (TTS) 기능이 있다면 쉽습니다, 파이썬 바인딩이 없어도 됩니다. 대부분의 TTS 시스템에는 실행할 수 있는 명령행 프로그램이 있으며, 이것을 subprocess 를 사용하여 처리기에서 호출 할 수 있습니다. 여기서 TTS 명령행 프로그램이 사용자와 상호 작용하거나, 완료하는 데 오랜 시간이 걸릴 것으로 기대되지 않으며, 로그 되는 메시지의 빈도가 메시지로 사용자를 압도할 정도로 높지 않으며, 메시지는 동시에 처리되지 않고 한 번에 하나씩 읽어도 된다고 가정합니다. 아래의 예제 구현은 다음 메시지가 처리되기 전에 하나의 메시지를 다 읽을 때까지 대기하고, 이 때문에 다른 처리기가 대기 상태로 유지될 수 있습니다. 다음은 espeak TTS 패키지가 사용 가능하다고 가정하는 접근법을 보여주는 간단한 예입니다:

import logging
import subprocess
import sys

class TTSHandler(logging.Handler):
    def emit(self, record):
        msg = self.format(record)
        # Speak slowly in a female English voice
        cmd = ['espeak', '-s150', '-ven+f3', msg]
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT)
        # wait for the program to finish
        p.communicate()

def configure_logging():
    h = TTSHandler()
    root = logging.getLogger()
    root.addHandler(h)
    # the default formatter just returns the message
    root.setLevel(logging.DEBUG)

def main():
    logging.info('Hello')
    logging.debug('Goodbye')

if __name__ == '__main__':
    configure_logging()
    sys.exit(main())

실행하면, 이 스크립트는 여성 음성으로 “Hello”와 “Goodbye”를 차례대로 말합니다.

물론 위의 접근법은 다른 TTS 시스템과 명령행에서 실행되는 외부 프로그램을 통해 메시지를 처리 할 수 있는 전혀 다른 시스템에도 적용될 수 있습니다.

로깅 메시지를 버퍼링하고 조건부 출력하기

임시 영역에 메시지를 기록하고 특정 조건이 발생할 때만 메시지를 출력하려는 상황이 있을 수 있습니다. 예를 들어, 함수에서 디버그 이벤트를 로깅 하기를 원할 수 있습니다. 함수가 에러 없이 완료되면 수집된 디버그 정보로 로그를 어지럽히고 싶지 않지만, 에러가 있으면 에러뿐만 아니라 모든 디버그 정보를 출력하고 싶습니다.

다음은 로깅이 이러한 방식으로 작동하기 원하는 함수에 데코레이터를 사용하여 이를 수행할 방법을 보여주는 예제입니다. logging.handlers.MemoryHandler 를 사용하는데, 어떤 상황이 발생할 때까지 로그 된 이벤트를 버퍼링할 수 있도록 하고, 때가 되면 버퍼링 된 이벤트들이 flush 됩니다 - 처리를 위해 다른 처리기(target 처리기)로 전달됩니다. 기본적으로, MemoryHandler 는 버퍼가 다 차거나 수준이 지정된 임계값보다 크거나 같은 이벤트가 발생하면 플러시 됩니다. 사용자 정의 플러시 동작을 원할 경우, 이 조리법을 MemoryHandler 의 더 특수한 서브 클래스와 함께 사용할 수 있습니다.

예제 스크립트에는 간단한 함수 foo 가 있는데, 모든 로그 수준을 순회하면서, 어떤 수준으로 로그 할지를 sys.stderr 에 쓴 다음, 그 수준으로 실제 메시지를 로깅 합니다. 매개 변수를 foo 에 전달할 수 있는데, 참이면 ERROR 및 CRITICAL 수준으로 로그 합니다 - 그렇지 않으면 DEBUG, INFO 및 WARNING 수준에서만 로그 합니다.

이 스크립트는 필요한 조건부 로깅을 수행할 데코레이터로 foo 를 데코레이트 하기만 합니다. 데코레이터는 로거를 매개 변수로 받고 데코레이트 된 함수가 호출되는 동안 메모리 처리기를 연결합니다. 데코레이터는 target 처리기, 플러싱이 발생해야 하는 수준 및 버퍼 용량(버퍼 된 레코드의 수)을 추가로 매개 변수로 받을 수 있습니다. 이것들은 각각 sys.stderr 로 쓰는 StreamHandler, logging.ERROR, 100 을 기본값으로 합니다.

스크립트는 다음과 같습니다:

import logging
from logging.handlers import MemoryHandler
import sys

logger = logging.getLogger(__name__)
logger.addHandler(logging.NullHandler())

def log_if_errors(logger, target_handler=None, flush_level=None, capacity=None):
    if target_handler is None:
        target_handler = logging.StreamHandler()
    if flush_level is None:
        flush_level = logging.ERROR
    if capacity is None:
        capacity = 100
    handler = MemoryHandler(capacity, flushLevel=flush_level, target=target_handler)

    def decorator(fn):
        def wrapper(*args, **kwargs):
            logger.addHandler(handler)
            try:
                return fn(*args, **kwargs)
            except Exception:
                logger.exception('call failed')
                raise
            finally:
                super(MemoryHandler, handler).flush()
                logger.removeHandler(handler)
        return wrapper

    return decorator

def write_line(s):
    sys.stderr.write('%s\n' % s)

def foo(fail=False):
    write_line('about to log at DEBUG ...')
    logger.debug('Actually logged at DEBUG')
    write_line('about to log at INFO ...')
    logger.info('Actually logged at INFO')
    write_line('about to log at WARNING ...')
    logger.warning('Actually logged at WARNING')
    if fail:
        write_line('about to log at ERROR ...')
        logger.error('Actually logged at ERROR')
        write_line('about to log at CRITICAL ...')
        logger.critical('Actually logged at CRITICAL')
    return fail

decorated_foo = log_if_errors(logger)(foo)

if __name__ == '__main__':
    logger.setLevel(logging.DEBUG)
    write_line('Calling undecorated foo with False')
    assert not foo(False)
    write_line('Calling undecorated foo with True')
    assert foo(True)
    write_line('Calling decorated foo with False')
    assert not decorated_foo(False)
    write_line('Calling decorated foo with True')
    assert decorated_foo(True)

이 스크립트를 실행하면 다음과 같은 출력이 나타납니다.:

Calling undecorated foo with False
about to log at DEBUG ...
about to log at INFO ...
about to log at WARNING ...
Calling undecorated foo with True
about to log at DEBUG ...
about to log at INFO ...
about to log at WARNING ...
about to log at ERROR ...
about to log at CRITICAL ...
Calling decorated foo with False
about to log at DEBUG ...
about to log at INFO ...
about to log at WARNING ...
Calling decorated foo with True
about to log at DEBUG ...
about to log at INFO ...
about to log at WARNING ...
about to log at ERROR ...
Actually logged at DEBUG
Actually logged at INFO
Actually logged at WARNING
Actually logged at ERROR
about to log at CRITICAL ...
Actually logged at CRITICAL

보시다시피, 실제 로깅 출력은 심각도가 ERROR 이상인 이벤트가 기록될 때만 발생하지만, 이 경우 심각도가 낮은 이전 이벤트도 기록됩니다.

물론 전통적인 데코레이션 수단을 쓸 수 있습니다.:

@log_if_errors(logger)
def foo(fail=False):
    ...

Sending logging messages to email, with buffering

To illustrate how you can send log messages via email, so that a set number of messages are sent per email, you can subclass BufferingHandler. In the following example, which you can adapt to suit your specific needs, a simple test harness is provided which allows you to run the script with command line arguments specifying what you typically need to send things via SMTP. (Run the downloaded script with the -h argument to see the required and optional arguments.)

import logging
import logging.handlers
import smtplib

class BufferingSMTPHandler(logging.handlers.BufferingHandler):
    def __init__(self, mailhost, port, username, password, fromaddr, toaddrs,
                 subject, capacity):
        logging.handlers.BufferingHandler.__init__(self, capacity)
        self.mailhost = mailhost
        self.mailport = port
        self.username = username
        self.password = password
        self.fromaddr = fromaddr
        if isinstance(toaddrs, str):
            toaddrs = [toaddrs]
        self.toaddrs = toaddrs
        self.subject = subject
        self.setFormatter(logging.Formatter("%(asctime)s %(levelname)-5s %(message)s"))

    def flush(self):
        if len(self.buffer) > 0:
            try:
                smtp = smtplib.SMTP(self.mailhost, self.mailport)
                smtp.starttls()
                smtp.login(self.username, self.password)
                msg = "From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n" % (self.fromaddr, ','.join(self.toaddrs), self.subject)
                for record in self.buffer:
                    s = self.format(record)
                    msg = msg + s + "\r\n"
                smtp.sendmail(self.fromaddr, self.toaddrs, msg)
                smtp.quit()
            except Exception:
                if logging.raiseExceptions:
                    raise
            self.buffer = []

if __name__ == '__main__':
    import argparse

    ap = argparse.ArgumentParser()
    aa = ap.add_argument
    aa('host', metavar='HOST', help='SMTP server')
    aa('--port', '-p', type=int, default=587, help='SMTP port')
    aa('user', metavar='USER', help='SMTP username')
    aa('password', metavar='PASSWORD', help='SMTP password')
    aa('to', metavar='TO', help='Addressee for emails')
    aa('sender', metavar='SENDER', help='Sender email address')
    aa('--subject', '-s',
       default='Test Logging email from Python logging module (buffering)',
       help='Subject of email')
    options = ap.parse_args()
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)
    h = BufferingSMTPHandler(options.host, options.port, options.user,
                             options.password, options.sender,
                             options.to, options.subject, 10)
    logger.addHandler(h)
    for i in range(102):
        logger.info("Info index = %d", i)
    h.flush()
    h.close()

If you run this script and your SMTP server is correctly set up, you should find that it sends eleven emails to the addressee you specify. The first ten emails will each have ten log messages, and the eleventh will have two messages. That makes up 102 messages as specified in the script.

구성을 통해 UTC(GMT)로 시간을 포맷하기

Sometimes you want to format times using UTC, which can be done using a class such as UTCFormatter, shown below:

import logging
import time

class UTCFormatter(logging.Formatter):
    converter = time.gmtime

이제 Formatter 대신 코드에서 UTCFormatter 를 사용할 수 있습니다. 구성을 통해 이를 수행하려면, 다음에 나오는 완전한 예제에 의해 설명된 접근법으로 dictConfig() API를 사용할 수 있습니다:

import logging
import logging.config
import time

class UTCFormatter(logging.Formatter):
    converter = time.gmtime

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'utc': {
            '()': UTCFormatter,
            'format': '%(asctime)s %(message)s',
        },
        'local': {
            'format': '%(asctime)s %(message)s',
        }
    },
    'handlers': {
        'console1': {
            'class': 'logging.StreamHandler',
            'formatter': 'utc',
        },
        'console2': {
            'class': 'logging.StreamHandler',
            'formatter': 'local',
        },
    },
    'root': {
        'handlers': ['console1', 'console2'],
   }
}

if __name__ == '__main__':
    logging.config.dictConfig(LOGGING)
    logging.warning('The local time is %s', time.asctime())

이 스크립트를 실행하면, 다음과 같은 내용을 인쇄합니다:

2015-10-17 12:53:29,501 The local time is Sat Oct 17 13:53:29 2015
2015-10-17 13:53:29,501 The local time is Sat Oct 17 13:53:29 2015

시간이 한 처리기에서는 UTC로, 다른 처리기에서는 지역 시간으로 포맷되는 것을 보여줍니다.

선택적 로깅을 위해 컨텍스트 관리자 사용하기

로깅 구성을 일시적으로 변경하고 무언가를 한 후에 되돌리는 것이 유용할 때가 있습니다. 이를 위해, 컨텍스트 관리자는 로깅 컨텍스트를 저장하고 복원하는 가장 분명한 방법입니다. 다음은 그러한 컨텍스트 관리자의 간단한 예입니다. 컨텍스트 관리자의 범위 안에서 선택적으로 로깅 수준을 변경하고 로깅 처리기를 추가 할 수 있습니다:

import logging
import sys

class LoggingContext:
    def __init__(self, logger, level=None, handler=None, close=True):
        self.logger = logger
        self.level = level
        self.handler = handler
        self.close = close

    def __enter__(self):
        if self.level is not None:
            self.old_level = self.logger.level
            self.logger.setLevel(self.level)
        if self.handler:
            self.logger.addHandler(self.handler)

    def __exit__(self, et, ev, tb):
        if self.level is not None:
            self.logger.setLevel(self.old_level)
        if self.handler:
            self.logger.removeHandler(self.handler)
        if self.handler and self.close:
            self.handler.close()
        # implicit return of None => don't swallow exceptions

수준 값을 지정하면, 로거의 수준은 컨텍스트 관리자가 적용되는 with 블록의 범위 안에서 해당 값으로 설정됩니다. 처리기를 지정하면, 블록 진입 시 로거에 추가되고 블록에서 빠져나갈 때 제거됩니다. 블록을 빠져나갈 때 처리기를 닫도록 관리자에게 요청할 수도 있습니다 - 더는 처리기가 필요하지 않으면 이렇게 할 수 있습니다.

작동 원리를 보여주기 위해, 다음 코드 블록을 위에 추가 할 수 있습니다:

if __name__ == '__main__':
    logger = logging.getLogger('foo')
    logger.addHandler(logging.StreamHandler())
    logger.setLevel(logging.INFO)
    logger.info('1. This should appear just once on stderr.')
    logger.debug('2. This should not appear.')
    with LoggingContext(logger, level=logging.DEBUG):
        logger.debug('3. This should appear once on stderr.')
    logger.debug('4. This should not appear.')
    h = logging.StreamHandler(sys.stdout)
    with LoggingContext(logger, level=logging.DEBUG, handler=h, close=True):
        logger.debug('5. This should appear twice - once on stderr and once on stdout.')
    logger.info('6. This should appear just once on stderr.')
    logger.debug('7. This should not appear.')

우리는 초기에 로거 수준을 INFO 로 설정합니다. 그래서 메시지 #1은 나타나고 메시지 #2는 나타나지 않습니다. 그다음에 with 블록에서 수준을 DEBUG 로 임시 변경하면, 메시지 #3이 나타납니다. 블록이 종료되면 로거 수준이 INFO 로 복원되므로, 메시지 #4가 표시되지 않습니다. 그다음 with 블록에서 수준을 다시 DEBUG 로 다시 설정하지만, sys.stdout 으로 쓰는 처리기도 추가합니다. 따라서 메시지 #5는 콘솔에 두 번 표시됩니다 (stderr 를 통해 한 번, stdout 을 통해 한 번). with 문장이 완료된 후에 상태는 이전과 같으므로, (메시지 #1처럼) 메시지 #6이 나타나고, (메시지 #2처럼) 메시지 #7은 보이지 않습니다.

이렇게 만든 스크립트를 실행하면, 결과는 다음과 같습니다:

$ python logctx.py
1. This should appear just once on stderr.
3. This should appear once on stderr.
5. This should appear twice - once on stderr and once on stdout.
5. This should appear twice - once on stderr and once on stdout.
6. This should appear just once on stderr.

다시 실행하면서 stderr 를 /dev/null 로 리디렉트하면, 다음과 같이 stdout 으로 출력된 메시지만 나타납니다:

$ python logctx.py 2>/dev/null
5. This should appear twice - once on stderr and once on stdout.

다시 한번, 하지만 stdout 을 /dev/null 로 리디렉트하면, 이렇게 됩니다:

$ python logctx.py >/dev/null
1. This should appear just once on stderr.
3. This should appear once on stderr.
5. This should appear twice - once on stderr and once on stdout.
6. This should appear just once on stderr.

이 경우, stdout 에 인쇄된 메시지 #5는 예상대로 나타나지 않습니다.

물론 여기서 설명한 방법을 일반화 할 수 있습니다. 예를 들어 로깅 필터를 임시로 첨부 할 수 있습니다. 위의 코드는 파이썬 2와 파이썬 3에서 모두 작동합니다.

CLI 응용 프로그램 시작 템플릿

다음과 같은 것들을 하는 방법을 보여주는 예입니다:

명령 줄 인자에 기반한 로깅 수준 사용하기

별도의 파일에 있는 여러 부속 명령으로 분기하고, 모두 일관된 방식으로 같은 수준에서 로깅 하기

간단하고 최소의 구성을 사용하기

어떤 서비스를 중지, 시작 또는 다시 시작하는 작업을 위한 명령 줄 응용 프로그램이 있다고 가정합니다. 이것은 예시의 목적을 위해 start.py, stop.py 및 restart.py에 개별 명령이 구현되고, 응용 프로그램의 메인 스크립트는 app.py 파일이 되도록 구성할 수 있습니다. 명령 줄 인자를 통해 응용 프로그램의 상세도를 제어하려고 하고, logging.INFO를 기본값으로 한다고 더 가정해 봅시다. app.py를 작성할 수 있는 한 가지 방법은 다음과 같습니다:

import argparse
import importlib
import logging
import os
import sys

def main(args=None):
    scriptname = os.path.basename(__file__)
    parser = argparse.ArgumentParser(scriptname)
    levels = ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL')
    parser.add_argument('--log-level', default='INFO', choices=levels)
    subparsers = parser.add_subparsers(dest='command',
                                       help='Available commands:')
    start_cmd = subparsers.add_parser('start', help='Start a service')
    start_cmd.add_argument('name', metavar='NAME',
                           help='Name of service to start')
    stop_cmd = subparsers.add_parser('stop',
                                     help='Stop one or more services')
    stop_cmd.add_argument('names', metavar='NAME', nargs='+',
                          help='Name of service to stop')
    restart_cmd = subparsers.add_parser('restart',
                                        help='Restart one or more services')
    restart_cmd.add_argument('names', metavar='NAME', nargs='+',
                             help='Name of service to restart')
    options = parser.parse_args()
    # the code to dispatch commands could all be in this file. For the purposes
    # of illustration only, we implement each command in a separate module.
    try:
        mod = importlib.import_module(options.command)
        cmd = getattr(mod, 'command')
    except (ImportError, AttributeError):
        print('Unable to find the code for command \'%s\'' % options.command)
        return 1
    # Could get fancy here and load configuration from file or dictionary
    logging.basicConfig(level=options.log_level,
                        format='%(levelname)s %(name)s %(message)s')
    cmd(options)

if __name__ == '__main__':
    sys.exit(main())

그리고 start, stop 및 restart 명령은 별도의 모듈로 구현할 수 있습니다, 가령 시작하려면:

# start.py
import logging

logger = logging.getLogger(__name__)

def command(options):
    logger.debug('About to start %s', options.name)
    # actually do the command processing here ...
    logger.info('Started the \'%s\' service.', options.name)

그리고 멈추려면:

# stop.py
import logging

logger = logging.getLogger(__name__)

def command(options):
    n = len(options.names)
    if n == 1:
        plural = ''
        services = '\'%s\'' % options.names[0]
    else:
        plural = 's'
        services = ', '.join('\'%s\'' % name for name in options.names)
        i = services.rfind(', ')
        services = services[:i] + ' and ' + services[i + 2:]
    logger.debug('About to stop %s', services)
    # actually do the command processing here ...
    logger.info('Stopped the %s service%s.', services, plural)

비슷하게, 다시 시작하려면:

# restart.py
import logging

logger = logging.getLogger(__name__)

def command(options):
    n = len(options.names)
    if n == 1:
        plural = ''
        services = '\'%s\'' % options.names[0]
    else:
        plural = 's'
        services = ', '.join('\'%s\'' % name for name in options.names)
        i = services.rfind(', ')
        services = services[:i] + ' and ' + services[i + 2:]
    logger.debug('About to restart %s', services)
    # actually do the command processing here ...
    logger.info('Restarted the %s service%s.', services, plural)

이 응용 프로그램을 기본 로그 수준으로 실행하면, 이런 출력을 얻습니다:

$ python app.py start foo
INFO start Started the 'foo' service.

$ python app.py stop foo bar
INFO stop Stopped the 'foo' and 'bar' services.

$ python app.py restart foo bar baz
INFO restart Restarted the 'foo', 'bar' and 'baz' services.

첫 번째 단어는 로깅 수준이고, 두 번째 단어는 이벤트가 로그 된 장소의 모듈이나 패키지 이름입니다.

로깅 수준을 변경하면, 로그로 전송되는 정보를 변경할 수 있습니다. 예를 들어, 우리가 더 많은 정보를 원한다면:

$ python app.py --log-level DEBUG start foo
DEBUG start About to start foo
INFO start Started the 'foo' service.

$ python app.py --log-level DEBUG stop foo bar
DEBUG stop About to stop 'foo' and 'bar'
INFO stop Stopped the 'foo' and 'bar' services.

$ python app.py --log-level DEBUG restart foo bar baz
DEBUG restart About to restart 'foo', 'bar' and 'baz'
INFO restart Restarted the 'foo', 'bar' and 'baz' services.

그리고 덜 원한다면:

$ python app.py --log-level WARNING start foo
$ python app.py --log-level WARNING stop foo bar
$ python app.py --log-level WARNING restart foo bar baz

이 경우, WARNING 수준 이상으로 아무것도 로그 하지 않았으므로, 명령은 콘솔에 아무것도 인쇄하지 않습니다.

로깅을 위한 Qt GUI

A question that comes up from time to time is about how to log to a GUI application. The Qt [https://www.qt.io/] framework is a popular cross-platform UI framework with Python bindings using PySide2 [https://pypi.org/project/PySide2/] or PyQt5 [https://pypi.org/project/PyQt5/] libraries.

다음 예는 Qt GUI에 로그 하는 방법을 보여줍니다. 이것은 콜러블을 취하는 간단한 QtHandler 클래스를 소개합니다. 이 클래스는 GUI 업데이트를 하는 메인 스레드의 슬롯이어야 합니다. 또한 UI 자체 (수동 로깅을 위한 버튼을 통해) 뿐만 아니라 백그라운드에서 작업하는 작업자 스레드에서 GUI에 로그 하는 방법을 보여주기 위해 작업자 스레드도 만듭니다 (여기서는, 단지 임의의 짧은 지연을 주고 임의의 수준으로 메시지를 로깅 합니다).

작업자 스레드는 threading 모듈 대신 Qt의 QThread 클래스를 사용하여 구현되는데, 다른 Qt 구성 요소와 더 잘 통합되는 QThread를 사용해야 하는 상황이 있기 때문입니다.

The code should work with recent releases of any of PySide6, PyQt6, PySide2 or PyQt5. You should be able to adapt the approach to earlier versions of Qt. Please refer to the comments in the code snippet for more detailed information.

import datetime
import logging
import random
import sys
import time

# Deal with minor differences between different Qt packages
try:
    from PySide6 import QtCore, QtGui, QtWidgets
    Signal = QtCore.Signal
    Slot = QtCore.Slot
except ImportError:
    try:
        from PyQt6 import QtCore, QtGui, QtWidgets
        Signal = QtCore.pyqtSignal
        Slot = QtCore.pyqtSlot
    except ImportError:
        try:
            from PySide2 import QtCore, QtGui, QtWidgets
            Signal = QtCore.Signal
            Slot = QtCore.Slot
        except ImportError:
            from PyQt5 import QtCore, QtGui, QtWidgets
            Signal = QtCore.pyqtSignal
            Slot = QtCore.pyqtSlot

logger = logging.getLogger(__name__)

#
# Signals need to be contained in a QObject or subclass in order to be correctly
# initialized.
#
class Signaller(QtCore.QObject):
    signal = Signal(str, logging.LogRecord)

#
# Output to a Qt GUI is only supposed to happen on the main thread. So, this
# handler is designed to take a slot function which is set up to run in the main
# thread. In this example, the function takes a string argument which is a
# formatted log message, and the log record which generated it. The formatted
# string is just a convenience - you could format a string for output any way
# you like in the slot function itself.
#
# You specify the slot function to do whatever GUI updates you want. The handler
# doesn't know or care about specific UI elements.
#
class QtHandler(logging.Handler):
    def __init__(self, slotfunc, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.signaller = Signaller()
        self.signaller.signal.connect(slotfunc)

    def emit(self, record):
        s = self.format(record)
        self.signaller.signal.emit(s, record)

#
# This example uses QThreads, which means that the threads at the Python level
# are named something like "Dummy-1". The function below gets the Qt name of the
# current thread.
#
def ctname():
    return QtCore.QThread.currentThread().objectName()

#
# Used to generate random levels for logging.
#
LEVELS = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
          logging.CRITICAL)

#
# This worker class represents work that is done in a thread separate to the
# main thread. The way the thread is kicked off to do work is via a button press
# that connects to a slot in the worker.
#
# Because the default threadName value in the LogRecord isn't much use, we add
# a qThreadName which contains the QThread name as computed above, and pass that
# value in an "extra" dictionary which is used to update the LogRecord with the
# QThread name.
#
# This example worker just outputs messages sequentially, interspersed with
# random delays of the order of a few seconds.
#
class Worker(QtCore.QObject):
    @Slot()
    def start(self):
        extra = {'qThreadName': ctname() }
        logger.debug('Started work', extra=extra)
        i = 1
        # Let the thread run until interrupted. This allows reasonably clean
        # thread termination.
        while not QtCore.QThread.currentThread().isInterruptionRequested():
            delay = 0.5 + random.random() * 2
            time.sleep(delay)
            try:
                if random.random() < 0.1:
                    raise ValueError('Exception raised: %d' % i)
                else:
                    level = random.choice(LEVELS)
                    logger.log(level, 'Message after delay of %3.1f: %d', delay, i, extra=extra)
            except ValueError as e:
                logger.exception('Failed: %s', e, extra=extra)
            i += 1

#
# Implement a simple UI for this cookbook example. This contains:
#
# * A read-only text edit window which holds formatted log messages
# * A button to start work and log stuff in a separate thread
# * A button to log something from the main thread
# * A button to clear the log window
#
class Window(QtWidgets.QWidget):

    COLORS = {
        logging.DEBUG: 'black',
        logging.INFO: 'blue',
        logging.WARNING: 'orange',
        logging.ERROR: 'red',
        logging.CRITICAL: 'purple',
    }

    def __init__(self, app):
        super().__init__()
        self.app = app
        self.textedit = te = QtWidgets.QPlainTextEdit(self)
        # Set whatever the default monospace font is for the platform
        f = QtGui.QFont('nosuchfont')
        if hasattr(f, 'Monospace'):
            f.setStyleHint(f.Monospace)
        else:
            f.setStyleHint(f.StyleHint.Monospace)  # for Qt6
        te.setFont(f)
        te.setReadOnly(True)
        PB = QtWidgets.QPushButton
        self.work_button = PB('Start background work', self)
        self.log_button = PB('Log a message at a random level', self)
        self.clear_button = PB('Clear log window', self)
        self.handler = h = QtHandler(self.update_status)
        # Remember to use qThreadName rather than threadName in the format string.
        fs = '%(asctime)s %(qThreadName)-12s %(levelname)-8s %(message)s'
        formatter = logging.Formatter(fs)
        h.setFormatter(formatter)
        logger.addHandler(h)
        # Set up to terminate the QThread when we exit
        app.aboutToQuit.connect(self.force_quit)

        # Lay out all the widgets
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(te)
        layout.addWidget(self.work_button)
        layout.addWidget(self.log_button)
        layout.addWidget(self.clear_button)
        self.setFixedSize(900, 400)

        # Connect the non-worker slots and signals
        self.log_button.clicked.connect(self.manual_update)
        self.clear_button.clicked.connect(self.clear_display)

        # Start a new worker thread and connect the slots for the worker
        self.start_thread()
        self.work_button.clicked.connect(self.worker.start)
        # Once started, the button should be disabled
        self.work_button.clicked.connect(lambda : self.work_button.setEnabled(False))

    def start_thread(self):
        self.worker = Worker()
        self.worker_thread = QtCore.QThread()
        self.worker.setObjectName('Worker')
        self.worker_thread.setObjectName('WorkerThread')  # for qThreadName
        self.worker.moveToThread(self.worker_thread)
        # This will start an event loop in the worker thread
        self.worker_thread.start()

    def kill_thread(self):
        # Just tell the worker to stop, then tell it to quit and wait for that
        # to happen
        self.worker_thread.requestInterruption()
        if self.worker_thread.isRunning():
            self.worker_thread.quit()
            self.worker_thread.wait()
        else:
            print('worker has already exited.')

    def force_quit(self):
        # For use when the window is closed
        if self.worker_thread.isRunning():
            self.kill_thread()

    # The functions below update the UI and run in the main thread because
    # that's where the slots are set up

    @Slot(str, logging.LogRecord)
    def update_status(self, status, record):
        color = self.COLORS.get(record.levelno, 'black')
        s = '<pre><font color="%s">%s</font></pre>' % (color, status)
        self.textedit.appendHtml(s)

    @Slot()
    def manual_update(self):
        # This function uses the formatted message passed in, but also uses
        # information from the record to format the message in an appropriate
        # color according to its severity (level).
        level = random.choice(LEVELS)
        extra = {'qThreadName': ctname() }
        logger.log(level, 'Manually logged!', extra=extra)

    @Slot()
    def clear_display(self):
        self.textedit.clear()

def main():
    QtCore.QThread.currentThread().setObjectName('MainThread')
    logging.getLogger().setLevel(logging.DEBUG)
    app = QtWidgets.QApplication(sys.argv)
    example = Window(app)
    example.show()
    if hasattr(app, 'exec'):
        rc = app.exec()
    else:
        rc = app.exec_()
    sys.exit(rc)

if __name__=='__main__':
    main()

Logging to syslog with RFC5424 support

Although RFC 5424 [https://datatracker.ietf.org/doc/html/rfc5424.html] dates from 2009, most syslog servers are configured by default to use the older RFC 3164 [https://datatracker.ietf.org/doc/html/rfc3164.html], which hails from 2001. When logging was added to Python in 2003, it supported the earlier (and only existing) protocol at the time. Since RFC5424 came out, as there has not been widespread deployment of it in syslog servers, the SysLogHandler functionality has not been updated.

RFC 5424 contains some useful features such as support for structured data, and if you need to be able to log to a syslog server with support for it, you can do so with a subclassed handler which looks something like this:

import datetime
import logging.handlers
import re
import socket
import time

class SysLogHandler5424(logging.handlers.SysLogHandler):

    tz_offset = re.compile(r'([+-]\d{2})(\d{2})$')
    escaped = re.compile(r'([\]"\\])')

    def __init__(self, *args, **kwargs):
        self.msgid = kwargs.pop('msgid', None)
        self.appname = kwargs.pop('appname', None)
        super().__init__(*args, **kwargs)

    def format(self, record):
        version = 1
        asctime = datetime.datetime.fromtimestamp(record.created).isoformat()
        m = self.tz_offset.match(time.strftime('%z'))
        has_offset = False
        if m and time.timezone:
            hrs, mins = m.groups()
            if int(hrs) or int(mins):
                has_offset = True
        if not has_offset:
            asctime += 'Z'
        else:
            asctime += f'{hrs}:{mins}'
        try:
            hostname = socket.gethostname()
        except Exception:
            hostname = '-'
        appname = self.appname or '-'
        procid = record.process
        msgid = '-'
        msg = super().format(record)
        sdata = '-'
        if hasattr(record, 'structured_data'):
            sd = record.structured_data
            # This should be a dict where the keys are SD-ID and the value is a
            # dict mapping PARAM-NAME to PARAM-VALUE (refer to the RFC for what these
            # mean)
            # There's no error checking here - it's purely for illustration, and you
            # can adapt this code for use in production environments
            parts = []

            def replacer(m):
                g = m.groups()
                return '\\' + g[0]

            for sdid, dv in sd.items():
                part = f'[{sdid}'
                for k, v in dv.items():
                    s = str(v)
                    s = self.escaped.sub(replacer, s)
                    part += f' {k}="{s}"'
                part += ']'
                parts.append(part)
            sdata = ''.join(parts)
        return f'{version} {asctime} {hostname} {appname} {procid} {msgid} {sdata} {msg}'

You’ll need to be familiar with RFC 5424 to fully understand the above code, and it may be that you have slightly different needs (e.g. for how you pass structural data to the log). Nevertheless, the above should be adaptable to your speciric needs. With the above handler, you’d pass structured data using something like this:

sd = {
    'foo@12345': {'bar': 'baz', 'baz': 'bozz', 'fizz': r'buzz'},
    'foo@54321': {'rab': 'baz', 'zab': 'bozz', 'zzif': r'buzz'}
}
extra = {'structured_data': sd}
i = 1
logger.debug('Message %d', i, extra=extra)

How to treat a logger like an output stream

Sometimes, you need to interface to a third-party API which expects a file-like object to write to, but you want to direct the API’s output to a logger. You can do this using a class which wraps a logger with a file-like API. Here’s a short script illustrating such a class:

import logging

class LoggerWriter:
    def __init__(self, logger, level):
        self.logger = logger
        self.level = level

    def write(self, message):
        if message != '\n':  # avoid printing bare newlines, if you like
            self.logger.log(self.level, message)

    def flush(self):
        # doesn't actually do anything, but might be expected of a file-like
        # object - so optional depending on your situation
        pass

    def close(self):
        # doesn't actually do anything, but might be expected of a file-like
        # object - so optional depending on your situation. You might want
        # to set a flag so that later calls to write raise an exception
        pass

def main():
    logging.basicConfig(level=logging.DEBUG)
    logger = logging.getLogger('demo')
    info_fp = LoggerWriter(logger, logging.INFO)
    debug_fp = LoggerWriter(logger, logging.DEBUG)
    print('An INFO message', file=info_fp)
    print('A DEBUG message', file=debug_fp)

if __name__ == "__main__":
    main()

When this script is run, it prints

INFO:demo:An INFO message
DEBUG:demo:A DEBUG message

You could also use LoggerWriter to redirect sys.stdout and sys.stderr by doing something like this:

import sys

sys.stdout = LoggerWriter(logger, logging.INFO)
sys.stderr = LoggerWriter(logger, logging.WARNING)

You should do this after configuring logging for your needs. In the above example, the basicConfig() call does this (using the sys.stderr value before it is overwritten by a LoggerWriter instance). Then, you’d get this kind of result:

>>> print('Foo')
INFO:demo:Foo
>>> print('Bar', file=sys.stderr)
WARNING:demo:Bar
>>>

Of course, the examples above show output according to the format used by basicConfig(), but you can use a different formatter when you configure logging.

Note that with the above scheme, you are somewhat at the mercy of buffering and the sequence of write calls which you are intercepting. For example, with the definition of LoggerWriter above, if you have the snippet

sys.stderr = LoggerWriter(logger, logging.WARNING)
1 / 0

then running the script results in

WARNING:demo:Traceback (most recent call last):

WARNING:demo:  File "/home/runner/cookbook-loggerwriter/test.py", line 53, in <module>

WARNING:demo:
WARNING:demo:main()
WARNING:demo:  File "/home/runner/cookbook-loggerwriter/test.py", line 49, in main

WARNING:demo:
WARNING:demo:1 / 0
WARNING:demo:ZeroDivisionError
WARNING:demo::
WARNING:demo:division by zero

As you can see, this output isn’t ideal. That’s because the underlying code which writes to sys.stderr makes multiple writes, each of which results in a separate logged line (for example, the last three lines above). To get around this problem, you need to buffer things and only output log lines when newlines are seen. Let’s use a slightly better implementation of LoggerWriter:

class BufferingLoggerWriter(LoggerWriter):
    def __init__(self, logger, level):
        super().__init__(logger, level)
        self.buffer = ''

    def write(self, message):
        if '\n' not in message:
            self.buffer += message
        else:
            parts = message.split('\n')
            if self.buffer:
                s = self.buffer + parts.pop(0)
                self.logger.log(self.level, s)
            self.buffer = parts.pop()
            for part in parts:
                self.logger.log(self.level, part)

This just buffers up stuff until a newline is seen, and then logs complete lines. With this approach, you get better output:

WARNING:demo:Traceback (most recent call last):
WARNING:demo:  File "/home/runner/cookbook-loggerwriter/main.py", line 55, in <module>
WARNING:demo:    main()
WARNING:demo:  File "/home/runner/cookbook-loggerwriter/main.py", line 52, in main
WARNING:demo:    1/0
WARNING:demo:ZeroDivisionError: division by zero

Patterns to avoid

Although the preceding sections have described ways of doing things you might need to do or deal with, it is worth mentioning some usage patterns which are unhelpful, and which should therefore be avoided in most cases. The following sections are in no particular order.

Opening the same log file multiple times

On Windows, you will generally not be able to open the same file multiple times as this will lead to a “file is in use by another process” error. However, on POSIX platforms you’ll not get any errors if you open the same file multiple times. This could be done accidentally, for example by:

Adding a file handler more than once which references the same file (e.g. by a copy/paste/forget-to-change error).

Opening two files that look different, as they have different names, but are the same because one is a symbolic link to the other.

Forking a process, following which both parent and child have a reference to the same file. This might be through use of the multiprocessing module, for example.

Opening a file multiple times might appear to work most of the time, but can lead to a number of problems in practice:

Logging output can be garbled because multiple threads or processes try to write to the same file. Although logging guards against concurrent use of the same handler instance by multiple threads, there is no such protection if concurrent writes are attempted by two different threads using two different handler instances which happen to point to the same file.

An attempt to delete a file (e.g. during file rotation) silently fails, because there is another reference pointing to it. This can lead to confusion and wasted debugging time - log entries end up in unexpected places, or are lost altogether. Or a file that was supposed to be moved remains in place, and grows in size unexpectedly despite size-based rotation being supposedly in place.

Use the techniques outlined in 여러 프로세스에서 단일 파일에 로깅 하기 to circumvent such issues.

Using loggers as attributes in a class or passing them as parameters

While there might be unusual cases where you’ll need to do this, in general there is no point because loggers are singletons. Code can always access a given logger instance by name using logging.getLogger(name), so passing instances around and holding them as instance attributes is pointless. Note that in other languages such as Java and C#, loggers are often static class attributes. However, this pattern doesn’t make sense in Python, where the module (and not the class) is the unit of software decomposition.

Adding handlers other than NullHandler to a logger in a library

Configuring logging by adding handlers, formatters and filters is the responsibility of the application developer, not the library developer. If you are maintaining a library, ensure that you don’t add handlers to any of your loggers other than a NullHandler instance.

Creating a lot of loggers

Loggers are singletons that are never freed during a script execution, and so creating lots of loggers will use up memory which can’t then be freed. Rather than create a logger per e.g. file processed or network connection made, use the existing mechanisms for passing contextual information into your logs and restrict the loggers created to those describing areas within your application (generally modules, but occasionally slightly more fine-grained than that).

Other resources

더 보기

모듈 logging

logging 모듈에 대한 API 레퍼런스

모듈 logging.config

logging 모듈용 구성 API.

모듈 logging.handlers

logging 모듈에 포함된 유용한 처리기.

Basic Tutorial

Advanced Tutorial

정규식 HOWTO

저자:

A.M. Kuchling <amk@amk.ca>

요약

이 설명서는 파이썬에서 re 모듈로 정규식을 사용하는 방법을 소개하는 입문서입니다. 라이브러리 레퍼런스의 해당 절보다 더 부드러운 소개를 제공합니다.

소개

정규식(RE, regexes 또는 regex 패턴이라고 불립니다)은 본질적으로 파이썬에 내장된 매우 작고 고도로 특수화된 프로그래밍 언어이며, re 모듈을 통해 사용할 수 있습니다. 이 작은 언어를 사용하여, 일치시키려는 가능한 문자열 집합에 대한 규칙을 지정합니다; 이 집합은 영어 문장, 전자 메일 주소, TeX 명령 또는 원하는 어떤 것이건 포함 할 수 있습니다. 그런 다음 “이 문자열이 패턴과 일치합니까?”, 또는 “이 문자열의 어느 부분에 패턴과 일치하는 것이 있습니까?”와 같은 질문을 할 수 있습니다. 또한 RE를 사용하여 문자열을 수정하거나 여러 방법으로 분할할 수 있습니다.

정규식 패턴은 일련의 바이트 코드로 컴파일된 다음 C로 작성된 일치 엔진에 의해 실행됩니다. 고급 사용을 위해서는, 엔진이 지정된 RE를 실행하는 방법에 주의를 기울이고, 더 빠르게 실행되는 바이트 코드를 생성하기 위해 특정한 방법으로 RE를 작성하는 것이 필요할 수 있습니다. 최적화는 일치 엔진의 내부를 잘 이해하고 있어야 하므로 이 설명서에서 다루지 않습니다.

정규식 언어는 비교적 작고 제한적이므로, 정규식을 사용하여 가능한 모든 문자열 처리 작업을 수행할 수 있는 것은 아닙니다. 정규식으로 수행할 수는 있지만, 표현이 아주 복잡해지는 작업도 있습니다. 이럴 때, 처리하기 위한 파이썬 코드를 작성하는 것이 더 나을 수 있습니다; 파이썬 코드는 정교한 정규식보다 느리겠지만, 아마도 더 이해하기 쉬울 겁니다.

단순한 패턴

우리는 가능한 가장 단순한 정규식에 대해 배우는 것으로 시작합니다. 정규식은 문자열에 대한 연산에 사용되므로, 가장 일반적인 작업으로 시작하겠습니다: 문자 일치.

정규식의 기초가 되는 컴퓨터 과학(결정적인 혹은 비결정적인 유한 오토마타)에 대한 자세한 설명은, 컴파일러 작성에 관한 거의 모든 교과서를 참조 할 수 있습니다.

문자 일치

대부분 글자와 문자는 단순히 자신과 일치합니다. 예를 들어, 정규식 test는 문자열 test와 정확히 일치합니다. (이 RE가 Test나 TEST와 일치하도록 대/소문자를 구분하지 않는 모드를 활성화할 수 있습니다; 나중에 자세히 설명합니다.)

이 규칙에는 예외가 있습니다; 일부 문자는 특수한 메타 문자 (metacharacters)이며, 자신과 일치하지 않습니다. 그 대신, 그들은 일반적이지 않은 것을 일치시켜야 한다는 신호를 보냅니다. 또는 반복하거나 의미를 바꾸어 RE의 다른 부분에 영향을 줍니다. 이 설명서의 많은 부분은 다양한 메타 문자와 그 기능에 대해 논의하는데 할애하고 있습니다.

다음은 메타 문자의 전체 목록입니다; 이것들의 의미는 이 HOWTO의 나머지 부분에서 논의될 것입니다.

. ^ $ * + ? { } [ ] \ | ( )

우리가 살펴볼 첫 번째 메타 문자는 [와 ]입니다. 일치시키려는 문자 집합인 문자 클래스를 지정하는 데 사용됩니다. 문자는 개별적으로 나열되거나, 두 문자를 주고 '-'로 구분하여 문자의 범위를 나타낼 수 있습니다. 예를 들어, [abc] 는 a, b 또는 c 문자와 일치합니다; 이것은 [a-c]와 같은데, 같은 문자 집합을 표현하기 위해 범위를 사용합니다. 소문자들만 일치시키려면, RE가 [a-z]가 됩니다.

Metacharacters (except \) are not active inside classes. For example, [akm$] will match any of the characters 'a', 'k', 'm', or '$'; '$' is usually a metacharacter, but inside a character class it’s stripped of its special nature.

여집합 (complement set)을 사용해서 클래스에 나열되지 않은 문자를 일치시킬 수 있습니다. 이것은 클래스의 첫 번째 문자로 '^'를 포함하는 것으로 나타냅니다. 예를 들어, [^5] 는 '5'를 제외한 모든 문자와 일치합니다. 캐럿이 문자 클래스의 다른 곳에 나타나면, 특별한 의미가 없습니다. 예를 들어, [5^] 는 '5'나 '^'와 일치합니다.

아마도 가장 중요한 메타 문자는 백 슬래시(\)입니다. 파이썬 문자열 리터럴에서와 같이, 백 슬래시 다음에 다양한 특수 시퀀스를 알리는 다양한 문자가 따라올 수 있습니다. 또한, 모든 메타 문자를 이스케이프 처리하여 패턴으로 일치시킬 수 있도록 합니다. 예를 들어, [나 \와 일치시켜야 할 때, 특별한 의미를 제거하기 위해 앞에 백 슬래시를 붙일 수 있습니다: \[나 \\.

'\'로 시작하는 특수 시퀀스 중 일부는 숫자(digit) 집합, 글자(letter) 집합 또는 공백이 아닌 모든 것의 집합과 같이 종종 유용한 미리 정의된 문자 집합을 나타냅니다.

예를 들어 보겠습니다: \w는 모든 영숫자(alphanumeric character)와 일치합니다. 정규식 패턴을 바이트열로 표현하면, 이것은 [a-zA-Z0-9_] 클래스와 동등합니다. 정규식 패턴이 문자열이면, \w는 unicodedata 모듈이 제공하는 유니코드 데이터베이스에서 글자(letter)로 표시된 모든 문자를 일치시킵니다. 정규식을 컴파일할 때 re.ASCII 플래그를 제공하여 문자열 패턴에서 \w의 더 제한된 정의를 사용할 수 있습니다.

다음 특수 시퀀스 목록은 완전하지 않습니다. 유니코드 문자열 패턴에 대한 시퀀스와 확장 클래스 정의의 전체 목록은, 표준 라이브러리 레퍼런스에서 정규식 문법의 마지막 부분을 참조하십시오. 일반적으로, 유니코드 버전은 유니코드 데이터베이스의 적절한 범주에 있는 모든 문자와 일치합니다.

\d

모든 십진 숫자와 일치합니다; 이것은 클래스 [0-9]와 동등합니다.

\D

모든 비 숫자 문자와 일치합니다; 이것은 클래스 [^0-9]와 동등합니다.

\s

모든 공백 문자와 일치합니다; 이것은 클래스 [ \t\n\r\f\v] 와 동등합니다.

\S

모든 비 공백 문자와 일치합니다; 이것은 클래스 [^ \t\n\r\f\v] 와 동등합니다.

\w

모든 영숫자(alphanumeric character)와 일치합니다; 이것은 클래스 [a-zA-Z0-9_]와 동등합니다.

\W

모든 비 영숫자와 일치합니다; 이것은 클래스 [^a-zA-Z0-9_]와 동등합니다.

이 시퀀스들은 문자 클래스 내에 포함될 수 있습니다. 예를 들어, [\s,.] 는 모든 공백 문자, ',' 또는 '.'와 일치하는 문자 클래스입니다.

이 절의 마지막 메타 문자는 .입니다. 개행 문자를 제외한 모든 문자와 일치하며, 개행 문자와도 일치하는 대체 모드(re.DOTALL)가 있습니다. . 은 “모든 문자”와 일치시키려고 할 때 자주 사용됩니다.

반복하기

다양한 문자 집합을 일치시킬 수 있다는 것이 문자열에서 사용할 수 있는 메서드로 이미 가능하지 않은 것을 정규식이 수행할 수 있는 첫 번째 것입니다. 그러나, 이것이 정규식의 유일한 추가 기능이라면, 그다지 진보했다고 할 수 없습니다. 또 다른 기능은 RE의 일부가 특정 횟수만큼 반복되어야 한다고 지정할 수 있다는 것입니다.

우리가 살펴볼 반복을 위한 첫 번째 메타 문자는 *입니다. *는 리터럴 문자 '*'와 일치하지 않습니다; 대신 이전 문자를 정확히 한 번이 아닌 0번 이상 일치시킬 수 있도록 지정합니다.

예를 들어, ca*t는 'ct' (0개의 'a' 문자), 'cat' (1개의 'a'), 'caaat' (3개의 'a' 문자) 등과 일치합니다.

*와 같은 반복은 탐욕스럽습니다 (greedy); RE를 반복할 때, 일치 엔진은 가능한 한 여러 번 반복하려고 시도합니다. 패턴의 뒷부분이 일치하지 않으면, 일치 엔진은 되돌아가서 더 작은 반복으로 다시 시도합니다.

단계별 예제를 통해 더 명확하게 알 수 있습니다. 정규식 a[bcd]*b를 생각해 봅시다. 이 문자는 'a' 문자와 일치하고, 0개 이상의 [bcd] 클래스 문자가 뒤따르고, 마지막에 'b'로 끝납니다. 이제 이 RE를 문자열 'abcbd'와 일치시킨다고 상상해보십시오.

단계

일치된 것

설명

1

a

RE의 a가 일치합니다.

2

abcbd

엔진은 가능한 한 길게 [bcd]*와 일치시키려고 문자열의 끝까지 갑니다.

3

실패

엔진은 b를 일치하려고 시도하지만, 현재 위치가 문자열의 끝이므로 실패합니다.

4

abcb

물러서서, [bcd]*가 하나 적은 문자와 일치합니다.

5

실패

b를 다시 시도하지만, 현재 위치는 'd' 인 마지막 문자에 있습니다.

6

abc

다시 물러서서, [bcd]*가 bc하고 만 일치합니다.

6

abcb

b를 다시 시도합니다. 이번에는 현재 위치의 문자가 'b'이므로 성공합니다.

RE의 끝에 도달했으며, 'abcb'와 일치했습니다. 이것은 일치 엔진이 처음에는 갈 수 있는 데까지 가본 다음, 일치하는 것이 발견되지 않으면 점진적으로 물러서고, 나머지 RE의 나머지 부분을 반복해서 다시 시도하는 것을 보여줍니다. [bcd]*에 대한 일치 항목의 길이가 0이 될 때까지 물러서고, 그것마저도 실패하면, 엔진은 문자열이 RE와 전혀 일치하지 않는다고 결론을 내립니다.

또 다른 반복 메타 문자는 +인 데, 하나 이상과 일치합니다. *와 +의 차이점에 주의하십시오; *는 0 이상과 일치하므로, 반복되는 내용이 전혀 표시되지 않을 수 있습니다. 반면 +는 적어도 1번 이상 나타날 것을 요구합니다. 비슷한 예제를 사용하면, ca+t는 'cat' (1 'a'), 'caaat' (3 'a')와 일치하지만 'ct'와 일치하지는 않습니다.

There are two more repeating operators or quantifiers. The question mark character, ?, matches either once or zero times; you can think of it as marking something as being optional. For example, home-?brew matches either 'homebrew' or 'home-brew'.

The most complicated quantifier is {m,n}, where m and n are decimal integers. This quantifier means there must be at least m repetitions, and at most n. For example, a/{1,3}b will match 'a/b', 'a//b', and 'a///b'. It won’t match 'ab', which has no slashes, or 'a////b', which has four.

m이나 n을 생략 할 수 있습니다; 이때, 빠진 값에 대해 합리적인 값이 가정됩니다. m을 생략하면 0 하한으로 해석하는 반면, m을 생략하면 무한대의 상한을 뜻합니다.

The simplest case {m} matches the preceding item exactly m times. For example, a/{2}b will only match 'a//b'.

Readers of a reductionist bent may notice that the three other quantifiers can all be expressed using this notation. {0,} is the same as *, {1,} is equivalent to +, and {0,1} is the same as ?. It’s better to use *, +, or ? when you can, simply because they’re shorter and easier to read.

정규식 사용하기

이제 간단한 정규식을 살펴보았습니다. 실제로 파이썬에서 어떻게 사용해야 할까요? re 모듈은 정규식 엔진에 대한 인터페이스를 제공해서, RE를 객체로 컴파일한 다음 일치를 수행 할 수 있도록 합니다.

정규식 컴파일하기

정규식은 패턴 객체로 컴파일되는데, 패턴 일치를 검색하거나 문자열 치환을 수행하는 등의 다양한 작업을 위한 메서드를 갖고 있습니다.

>>> import re
>>> p = re.compile('ab*')
>>> p
re.compile('ab*')

re.compile()은 다양한 특수 기능과 문법 변형을 가능하게 하는 선택적 flags 인자도 받아들입니다. 나중에 사용할 수 있는 설정을 살펴보도록 하겠지만, 지금은 한 가지 예 만 보겠습니다:

>>> p = re.compile('ab*', re.IGNORECASE)

RE는 문자열로 re.compile()에 전달됩니다. 정규식이 핵심 파이썬 언어의 일부가 아니고, 정규식을 표현하기 위한 특수 문법이 만들어지지 않았기 때문에 RE는 문자열로 다뤄집니다. (RE를 전혀 필요로하지 않는 응용 프로그램이 있기 때문에, 이를 포함해서 언어 사양을 부풀릴 필요가 없습니다.) 대신, re 모듈은 socket이나 zlib 모듈과 마찬가지로 파이썬에 포함된 C 확장 모듈일 뿐입니다.

RE를 문자열에 넣는 것은 파이썬 언어가 더 간단하게 유지되도록 하지만, 다음 절의 주제인 한 가지 단점이 있습니다.

백 슬래시 전염병

앞에서 언급한 것처럼, 정규식은 백 슬래시 문자('\')를 사용하여 특수 형식을 나타내거나 특수 문자 특별한 의미를 갖지 않고 사용되도록 합니다. 이것은 파이썬이 문자열 리터럴에서 같은 목적으로 같은 문자를 사용하는 것과 충돌합니다.

LaTeX 파일에서 발견되는 문자열 \section과 일치하는 RE를 작성한다고 가정해 봅시다. 프로그램 코드에 무엇을 쓸지 알아내기 위해, 일치시키고자 하는 문자열로 시작하십시오. 그런 다음, 백 슬래시와 다른 메타 문자 앞에 백 슬래시를 붙여 이스케이프 처리하면, 문자열 \\section을 얻게 됩니다. re.compile()에 전달되어야 하는 결과 문자열은 \\section이어야 합니다. 그러나, 이를 파이썬 문자열 리터럴로 표현하려면, 두 개의 백 슬래시를 모두 다시 이스케이프 처리해야 합니다.

문자

단계

\section

일치시킬 텍스트 문자열

\\section

re.compile()을 위해 이스케이프 처리된 백 슬래시

"\\\\section"

문자열 리터럴을 위해 이스케이프 처리된 백 슬래시

즉, 리터럴 백 슬래시와 일치시키려면, RE 문자열로 '\\\\'을 작성해야 하는데, 정규식은 \\이어야하고, 일반 파이썬 문자열 리터럴 안에서 각 백 슬래시를 \\로 표현해야 하기 때문입니다. 백 슬래시를 반복적으로 사용하는 RE에서는, 수없이 반복되는 백 슬래시로 이어져, 결과 문자열을 이해하기 어렵게 만듭니다.

해결책은 정규식에 파이썬의 날 문자열 표기법을 사용하는 것입니다; 백 슬래시는 'r' 접두사가 붙은 문자열 리터럴에서 특별한 방법으로 처리되지 않아서, r"\n"는 '\'과 'n'을 포함하는 두 문자 문자열이지만, "\n"는 줄 넘김을 포함하는 한 문자 문자열입니다. 정규식은 종종 이 날 문자열 표기법을 사용하여 파이썬 코드로 작성됩니다.

또한, 정규식에서는 유효하지만, 파이썬 문자열 리터럴에서는 유효하지 않은 특수 이스케이프 시퀀스는 이제 DeprecationWarning을 발생시키고 결국에는 SyntaxError가 될 것입니다. 이는 날 문자열 표기법이나 백 슬래시 이스케이핑이 사용되지 않으면 시퀀스가 유효하지 않게 됨을 뜻합니다.

일반 문자열

날 문자열

"ab*"

r"ab*"

"\\\\section"

r"\\section"

"\\w+\\s+\\1"

r"\w+\s+\1"

일치 수행하기

일단 컴파일된 정규식을 나타내는 객체가 있으면, 이것으로 무엇을 할까요? 패턴 객체에는 여러 가지 메서드와 어트리뷰트가 있습니다. 가장 중요한 것만 여기서 다루어집니다; 전체 목록을 보려면 re 설명서를 참조하십시오.

메서드/어트리뷰트

목적

match()

문자열의 시작 부분에서 RE가 일치하는지 판단합니다.

search()

이 RE가 일치하는 위치를 찾으면서, 문자열을 훑습니다.

findall()

RE가 일치하는 모든 부분 문자열을 찾아 리스트로 반환합니다.

finditer()

RE가 일치하는 모든 부분 문자열을 찾아 이터레이터로 반환합니다.

match()와 search()는 일치하는 항목이 없으면 None을 반환합니다. 성공하면, 일치 객체 인스턴스가 반환되고, 일치에 대한 정보가 들어 있습니다: 어디에서 시작하고 끝나는지, 일치하는 부분 문자열 등입니다.

You can learn about this by interactively experimenting with the re module.

이 HOWTO는 예제에 표준 파이썬 인터프리터를 사용합니다. 먼저, 파이썬 인터프리터를 실행하고, re 모듈을 임포트 한 다음, RE를 컴파일하십시오:

>>> import re
>>> p = re.compile('[a-z]+')
>>> p
re.compile('[a-z]+')

이제, 다양한 문자열을 RE [a-z]+와 일치시켜볼 수 있습니다. +는 ‘하나 이상의 반복’을 의미하므로, 빈 문자열은 전혀 일치하지 않아야 합니다. 이때 match()는 None을 반환해야 하며, 인터프리터는 출력을 인쇄하지 않습니다. 분명하게 하기 위해 match()의 결과를 명시적으로 인쇄 할 수 있습니다.

>>> p.match("")
>>> print(p.match(""))
None

이제, 일치해야 하는 문자열을 시도해 봅시다, 가령 tempo. 이때, match()는 일치 객체를 반환하므로, 나중에 사용할 수 있도록 결과를 변수에 저장해야 합니다.

>>> m = p.match('tempo')
>>> m
<re.Match object; span=(0, 5), match='tempo'>

이제 match object를 조회하여 일치하는 문자열에 대한 정보를 얻을 수 있습니다. 일치 객체 인스턴스에는 여러 메서드와 어트리뷰트가 있습니다; 가장 중요한 것들은 다음과 같습니다:

메서드/어트리뷰트

목적

group()

RE와 일치하는 문자열을 반환합니다.

start()

일치의 시작 위치를 반환합니다

end()

일치의 끝 위치를 반환합니다

span()

일치의 (시작, 끝) 위치를 포함하는 튜플을 반환합니다.

이 메서드를 실험해보면 곧 그 의미가 분명해질 것입니다:

>>> m.group()
'tempo'
>>> m.start(), m.end()
(0, 5)
>>> m.span()
(0, 5)

group()은 RE에 의해 일치된 부분 문자열을 반환합니다. start()와 end()는 일치의 시작과 끝 인덱스를 반환합니다. span()은 시작과 끝 인덱스를 단일 튜플로 반환합니다. match() 메서드는 문자열의 시작 부분에서 RE가 일치하는지 검사하므로, start()는 항상 0입니다. 그러나, 패턴의 search() 메서드는 문자열을 훑기 때문에, 일치가 0에서 시작하지 않을 수 있습니다.

>>> print(p.match('::: message'))
None
>>> m = p.search('::: message'); print(m)
<re.Match object; span=(4, 11), match='message'>
>>> m.group()
'message'
>>> m.span()
(4, 11)

실제 프로그램에서, 가장 일반적인 스타일은 일치 객체를 변수에 저장한 다음, None인지 확인하는 것입니다. 보통 이런 식입니다:

p = re.compile( ... )
m = p.match( 'string goes here' )
if m:
    print('Match found: ', m.group())
else:
    print('No match')

두 패턴 메서드는 패턴에 대한 모든 일치를 반환합니다. findall()은 일치하는 문자열 리스트를 반환합니다:

>>> p = re.compile(r'\d+')
>>> p.findall('12 drummers drumming, 11 pipers piping, 10 lords a-leaping')
['12', '11', '10']

이 예제에서는 리터럴을 날 문자열 리터럴로 만드는 r 접두어가 필요한데, 일반적인 “요리된(cooked)” 문자열 리터럴에 있는, 정규식에서는 허락되지만, 파이썬에서 인식하지 못하는, 이스케이프 시퀀스가 이제 DeprecationWarning을 발생시키고, 결국에는 결국 SyntaxError가 될 것이기 때문입니다. 백 슬래시 전염병를 참조하십시오.

findall()은 결과로 반환하기 전에 전체 리스트를 만들어야 합니다. finditer() 메서드는 매치 객체 인스턴스의 시퀀스를 이터레이터로 반환합니다:

>>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...')
>>> iterator
<callable_iterator object at 0x...>
>>> for match in iterator:
...     print(match.span())
...
(0, 2)
(22, 24)
(29, 31)

모듈 수준 함수

패턴 객체를 생성하고 메서드를 호출해야만 하는 것은 아닙니다; re 모듈은 match(), search(), findall(), sub() 등의 최상위 수준 함수도 제공합니다. 이 함수들은 첫 번째 인자로 RE 문자열이 추가된 해당 패턴 메서드와 같은 인자를 취하고, 여전히 None이나 일치 객체 인스턴스를 반환합니다.

>>> print(re.match(r'From\s+', 'Fromage amk'))
None
>>> re.match(r'From\s+', 'From amk Thu May 14 19:12:10 1998')
<re.Match object; span=(0, 5), match='From '>

내부적으로, 이 함수는 단순히 패턴 객체를 만들고 적절한 메서드를 호출합니다. 또한 컴파일된 객체를 캐시에 저장하므로, 같은 RE를 사용하는 이후의 호출에서는 패턴을 반복해서 구문 분석할 필요가 없습니다.

이러한 모듈 수준의 함수를 사용해야 할까요, 아니면 패턴을 얻어서 메서드를 직접 호출해야 할까요? 루프 내에서 정규식에 액세스하고 있다면, 사전 컴파일이 몇 번의 함수 호출을 절약할 수 있습니다. 루프 바깥에서는, 내부 캐시 덕분에 큰 차이가 없습니다.

컴파일 플래그

컴파일 플래그를 사용하면 정규식의 작동 방식을 수정할 수 있습니다. 플래그는 re 모듈에서 IGNORECASE와 같은 긴 이름과 I와 같은 간단한 한 글자 형식의 두 가지 이름으로 사용 가능합니다. (Perl의 패턴 수정자에 익숙하다면, 한 글자 형식은 같은 글자를 사용합니다; 예를 들어, re.VERBOSE의 짧은 형식은 re.X입니다.) 다중 플래그는 비트별 OR 하여 지정할 수 있습니다; 예를 들어, re.I | re.M은 I와 M 플래그를 모두 설정합니다.

다음은 사용 가능한 플래그와 각 플래그에 대한 자세한 설명입니다.

플래그

의미

ASCII, A

\w, \b, \s 및 \d와 같은 여러 이스케이프가 해당 속성이 있는 ASCII 문자에만 일치하도록 합니다.

DOTALL, S

.가 개행 문자를 포함한 모든 문자와 일치하도록 합니다.

IGNORECASE, I

대소 문자 구분 없는 일치를 수행합니다.

LOCALE, L

로케일을 고려하는 일치를 수행합니다.

MULTILINE, M

다중 행 일치, ^와 $에 영향을 줍니다.

VERBOSE, X (‘확장’ 용)

더 명확하고 이해하기 쉽게 정리될 수 있는 상세한 RE를 활성화합니다.

re.I

re.IGNORECASE

대소 문자를 구분하지 않는 일치를 수행합니다; 문자 클래스와 리터럴 문자열은 대소 문자를 무시하여 문자와 일치합니다. 예를 들어 [A-Z]는 소문자와도 일치합니다. ASCII 플래그로 ASCII가 아닌 일치를 막지 않는 한, 전체 유니코드 일치도 작동합니다. 유니코드 패턴 [a-z]나 [A-Z]가 IGNORECASE 플래그와 함께 사용되면, 52 ASCII 문자와 4개의 추가 비 ASCII 문자와 일치합니다: ‘İ’ (U+0130, 위에 점이 있는 라틴 대문자 I), ‘ı’ (U+0131, 라틴 소문자 점 없는 i), ‘ſ’ (U+017F, 라틴 소문자 긴 s) 및 ‘K’ (U+212A, 켈빈 기호). Spam은 'Spam', 'spam', 'spAM' 또는 'ſpam'과 일치합니다 (마지막은 유니코드 모드에서만 일치합니다). 이 소문자화는 현재 로케일을 고려하지 않습니다; 고려하려면 LOCALE 플래그를 설정하면 됩니다.

re.L

re.LOCALE

\w, \W, \b, \B 및 대소 문자를 구분하지 않는 일치를 유니코드 데이터베이스 대신 현재 로케일에 의존하도록 만듭니다.

로케일은 언어 차이를 고려한 프로그램을 작성하는 데 도움이 되는 C 라이브러리의 기능입니다. 예를 들어, 인코딩된 프랑스어 텍스트를 처리할 때, 단어와 일치하도록 \w+를 쓰고 싶습니다, 하지만 \w는 바이트열 패턴에서 [A-Za-z] 문자 클래스하고만 일치합니다; é나 ç에 해당하는 바이트는 일치하지 않습니다. 시스템이 올바르게 구성되고 프랑스어 로케일이 선택되면, 특정 C 함수는 é에 해당하는 바이트도 문자로 간주하여야 함을 프로그램에 알립니다. 정규식을 컴파일할 때 LOCALE 플래그를 설정하면, 컴파일된 결과 객체가 \w에 대해 이러한 C 함수를 사용하게 됩니다; 더 느리기는 하지만, 기대하는 대로 \w+가 프랑스어 단어를 일치시킬 수 있습니다. 이 플래그의 사용은 파이썬 3에서는 권장하지 않는데, 로케일 메커니즘이 매우 신뢰성이 떨어지고, 한 번에 하나의 “컬처(culture)” 만 처리하고, 8비트 로케일에서 만 작동하기 때문입니다. 파이썬 3에서 유니코드 (str) 패턴에 대해 유니코드 일치가 기본적으로 이미 활성화되어 있으며, 다른 로케일/언어를 처리할 수 있습니다.

re.M

re.MULTILINE

(^과 $는 아직 설명되지 않았습니다; 메타 문자 더 보기 절에서 소개될 예정입니다.)

보통 ^는 문자열의 시작 부분에서만 일치하고, $는 문자열의 끝부분과 문자열 끝에 있는 줄 바꿈 (있다면) 바로 앞에서 일치합니다. 이 플래그를 지정하면 ^는 문자열 시작 부분과 문자열 내의 각 줄 시작 부분(각 줄 바꿈의 바로 뒤)에서 일치합니다. 비슷하게, $ 메타 문자는 문자열 끝과 각 줄의 끝(각 줄 바꿈 바로 앞)에서 일치합니다.

re.S

re.DOTALL

'.' 특수 문자가 개행 문자를 포함하는 모든 문자와 일치하도록 만듭니다; 이 플래그가 없으면, '.'는 개행 문자를 제외한 모든 문자와 일치합니다.

re.A

re.ASCII

\w, \W, \b, \B, \s 및 \S가 전체 유니코드 일치 대신 ASCII 전용 일치를 수행하도록 만듭니다. 유니코드 패턴에서만 의미가 있으며, 바이트열 패턴에서는 무시됩니다.

re.X

re.VERBOSE

이 플래그는 정규식을 포매팅하는 더 유연한 방법을 제공해서 더 가독성 있는 정규식을 작성할 수 있도록 합니다. 이 플래그가 지정되면, 문자 클래스에 있거나 이스케이프 되지 않은 백 슬래시 뒤에 있을 때를 제외하고, RE 문자열 내의 공백을 무시합니다; 이것은 RE를 보다 명확하게 구성하고 들여쓰기 할 수 있도록 합니다. 이 플래그는 RE 내에 엔진이 무시하는 주석을 넣을 수도 있게 합니다; 주석은 문자 클래스나 이스케이프 처리되지 않은 백 슬래시 뒤에 있지 않은 '#'로 표시됩니다.

예를 들어, 여기에 re.VERBOSE를 사용하는 RE가 있습니다; 얼마다 더 읽기 쉬워지는지 보이십니까?

charref = re.compile(r"""
 &[#]                # Start of a numeric entity reference
 (
     0[0-7]+         # Octal form
   | [0-9]+          # Decimal form
   | x[0-9a-fA-F]+   # Hexadecimal form
 )
 ;                   # Trailing semicolon
""", re.VERBOSE)

상세 설정이 없으면, RE는 이렇게 됩니다:

charref = re.compile("&#(0[0-7]+"
                     "|[0-9]+"
                     "|x[0-9a-fA-F]+);")

위의 예에서, 파이썬의 문자열 리터럴 자동 이어붙이기를 사용해서 RE를 더 작은 조각으로 나누었지만, re.VERBOSE를 사용하는 버전보다 여전히 이해하기가 어렵습니다.

더 많은 패턴 기능

지금까지 정규식의 일부 기능에 관해서만 설명했습니다. 이 절에서는, 몇 가지 새로운 메타 문자와 그룹을 사용하여 일치하는 텍스트의 부분을 꺼내는 방법을 다룹니다.

메타 문자 더 보기

우리가 아직 다루지 않은 몇 가지 메타 문자가 있습니다. 대부분 이 절에서 다룰 것입니다.

논의할 나머지 메타 문자 중 일부는 폭이 없는 어서션(zero-width assertions)입니다. 이들은 엔진이 문자열을 통해 앞으로 나아가도록 하지 않습니다; 대신, 문자를 전혀 소비하지 않고, 단순히 성공하거나 실패합니다. 예를 들어, \b는 현재 위치가 단어 경계에 위치한다는 어서션입니다; 위치는 \b에 의해 전혀 변경되지 않습니다. 이것은 폭이 없는 어서션을 반복해서는 안 된다는 뜻인데, 주어진 위치에서 일단 일치하면 명백히 무한한 횟수만큼 일치 할 수 있기 때문입니다.

|

대안, 또는 “or” 연산자. A와 B가 정규식이면, A|B는 A나 B와 일치하는 문자열과 일치합니다. |는 여러 문자로 된 문자열의 대안을 사용할 때 합리적으로 작동하도록 하기 위해 우선순위가 매우 낮습니다. Crow|Servo는 'Crow'나 'Servo'와 일치합니다, 'Cro', 'w'나 'S' 그리고 'ervo'가 아닙니다.

리터럴 '|'를 일치시키려면, \|를 사용하거나 [|] 처럼 문자 클래스 안에 넣으십시오.

^

줄의 시작 부분에 일치합니다. MULTILINE 플래그가 설정되어 있지 않은 한, 문자열 시작 부분에서만 일치합니다. MULTILINE 모드에서는, 문자열 내의 각 줄 바꿈 바로 뒤에서도 일치합니다.

예를 들어, From이라는 단어를 줄의 시작 부분에서만 일치시키려면, 사용할 RE는 ^From입니다.

>>> print(re.search('^From', 'From Here to Eternity'))
<re.Match object; span=(0, 4), match='From'>
>>> print(re.search('^From', 'Reciting From Memory'))
None

리터럴 '^'를 일치시키려면, \^를 사용하십시오.

$

줄의 끝부분과 일치하는데, 문자열의 끝이나 줄 바꿈 문자 다음에 오는 모든 위치로 정의됩니다.

>>> print(re.search('}$', '{block}'))
<re.Match object; span=(6, 7), match='}'>
>>> print(re.search('}$', '{block} '))
None
>>> print(re.search('}$', '{block}\n'))
<re.Match object; span=(6, 7), match='}'>

리터럴 '$'를 일치시키려면, \$를 사용하거나 [$] 처럼 문자 클래스 안에 넣으십시오.

\A

문자열의 시작 부분에서만 일치합니다. MULTILINE 모드가 아닐 때, \A와 ^는 실질적으로 같습니다. MULTILINE 모드에서는, 다릅니다: \A는 여전히 문자열의 시작 부분에서만 일치하지만, ^는 문자열 내의 줄 바꿈 문자 뒤에 오는 모든 위치에서 일치 할 수 있습니다.

\Z

문자열 끝부분에서만 일치합니다.

\b

단어 경계. 이것은 단어(word)의 시작이니 끝부분에서만 일치하는 폭이 없는 어서션입니다. 단어는 영숫자 문자의 시퀀스로 정의되므로, 단어의 끝은 공백이나 영숫자가 아닌 문자로 표시됩니다.

다음 예제는 완전한 단어일 때만 class와 일치합니다. 다른 단어 안에 포함되어 있으면 일치하지 않습니다.

>>> p = re.compile(r'\bclass\b')
>>> print(p.search('no class at all'))
<re.Match object; span=(3, 8), match='class'>
>>> print(p.search('the declassified algorithm'))
None
>>> print(p.search('one subclass is'))
None

이 특수 시퀀스를 사용할 때 기억해야 할 두 가지 미묘한 점이 있습니다. 첫째, 이것은 파이썬의 문자열 리터럴과 정규식 시퀀스 간의 최악의 충돌입니다. 파이썬의 문자열 리터럴에서 \b는 ASCII 값 8을 갖는 백스페이스 문자입니다. 날 문자열을 사용하지 않으면, 파이썬이 \b를 백스페이스로 변환하고, 여러분의 RE는 예상대로 일치하지 않습니다. 다음 예제는 앞의 RE와 같아 보이지만, RE 문자열 앞의 'r'가 빠졌습니다.

>>> p = re.compile('\bclass\b')
>>> print(p.search('no class at all'))
None
>>> print(p.search('\b' + 'class' + '\b'))
<re.Match object; span=(0, 7), match='\x08class\x08'>

둘째, 이 어서선이 사용되지 않는 문자 클래스 내에서, \b는 파이썬의 문자열 리터럴과의 호환성을 위해 백스페이스 문자를 나타냅니다.

\B

또 다른 폭이 없는 어서션, 이것은 \b의 반대이며, 현재 위치가 단어 경계에 있지 않을 때만 일치합니다.

그룹

종종 단지 RE가 일치하는지보다 많은 정보를 얻을 필요가 있습니다. 정규식은 종종 관심 있는 다른 구성 요소와 일치하는 몇 개의 서브 그룹으로 나누어진 RE를 작성하여 문자열을 해부하는 데 사용됩니다. 예를 들어, RFC-822 헤더 행은 다음과 같이 ':'로 구분된 헤더 이름과 값으로 나뉩니다:

From: author@example.com
User-Agent: Thunderbird 1.5.0.9 (X11/20061227)
MIME-Version: 1.0
To: editor@example.com

이것은 전체 헤더 행과 일치하는 정규식을 작성하고, 헤더 이름과 일치하는 그룹 하나와 헤더 값과 일치하는 다른 그룹을 가짐으로써 처리 할 수 있습니다.

Groups are marked by the '(', ')' metacharacters. '(' and ')' have much the same meaning as they do in mathematical expressions; they group together the expressions contained inside them, and you can repeat the contents of a group with a quantifier, such as *, +, ?, or {m,n}. For example, (ab)* will match zero or more repetitions of ab.

>>> p = re.compile('(ab)*')
>>> print(p.match('ababababab').span())
(0, 10)

'(', ')'로 표시된 그룹은 일치하는 텍스트의 시작과 끝 인덱스도 포착합니다; 이것은 group(), start(), end() 및 span()에 인자를 전달하여 꺼낼 수 있습니다. 그룹은 0부터 시작하여 번호가 매겨집니다. 그룹 0은 항상 존재합니다; 이것은 전체 RE이므로 일치 객체 메서드는 모두 그룹 0을 기본 인자로 사용합니다. 나중에 일치하는 텍스트 범위를 포착하지 않는 그룹을 표현하는 방법을 살펴보겠습니다.

>>> p = re.compile('(a)b')
>>> m = p.match('ab')
>>> m.group()
'ab'
>>> m.group(0)
'ab'

서브 그룹은 왼쪽에서 오른쪽으로 1부터 위로 번호가 매겨집니다. 그룹은 중첩될 수 있습니다; 숫자를 결정하려면, 왼쪽에서 오른쪽으로 가면서 여는 괄호 문자를 세십시오.

>>> p = re.compile('(a(b)c)d')
>>> m = p.match('abcd')
>>> m.group(0)
'abcd'
>>> m.group(1)
'abc'
>>> m.group(2)
'b'

group()으로는 한 번에 여러 개의 그룹 번호를 전달할 수 있으며, 이때 해당 그룹에 해당하는 값을 포함하는 튜플을 반환합니다.

>>> m.group(2,1,2)
('b', 'abc', 'b')

groups() 메서드는 모든 서브 그룹에 대한 문자열을 포함하는 튜플을 반환합니다, 1에서 최대까지.

>>> m.groups()
('abc', 'b')

패턴의 역참조를 사용하면 이전 포착 그룹의 내용이 문자열의 현재 위치에서도 발견되어야 한다고 지정할 수 있습니다. 예를 들어, \1은 그룹 1의 정확한 내용이 현재 위치에서 발견되면 성공하고, 그렇지 않으면 실패합니다. 파이썬의 문자열 리터럴은 백 슬래시 뒤에 숫자를 붙여 문자열에 임의의 문자를 포함할 수 있기 때문에, RE에 역참조를 포함할 때 날 문자열을 사용해야 합니다.

예를 들어, 다음 RE는 문자열에서 중복 단어를 감지합니다.

>>> p = re.compile(r'\b(\w+)\s+\1\b')
>>> p.search('Paris in the the spring').group()
'the the'

이와 같은 역참조는 단순히 문자열을 검색하는 데는 별로 유용하지 않습니다 — 이런 식으로 데이터를 반복하는 텍스트 형식은 거의 없습니다 — 하지만 곧 문자열 치환을 수행할 때 아주 유용하다는 것을 알게 될 것입니다.

비 포착 그룹과 이름 있는 그룹

정교한 RE는 관심 있는 부분 문자열을 포착하고 RE 자체를 그룹화하고 구조화하기 위해 많은 그룹을 사용할 수 있습니다. 복잡한 RE에서는, 그룹 번호를 추적하기가 어려워집니다. 이 문제를 해결하는 데 도움이 되는 두 가지 기능이 있습니다. 둘 다 정규식 확장에 같은 문법을 사용하므로, 그것부터 살펴보겠습니다.

Perl 5는 표준 정규식에 대한 강력한 추가 기능으로 유명합니다. 이러한 새로운 기능을 위해 Perl 개발자는 Perl의 정규식을 표준 RE와 혼란스러울 만큼 다르게 만들지 않으면서 한 글자 메타 문자나 \로 시작하는 새로운 특수 시퀀스를 선택할 수 없었습니다. 예를 들어, &를 새로운 메타 문자로 선택하면, 예전 정규식은 &가 일반 문자라고 가정하고 \&나 [&]로 작성하여 이스케이프 하지 않을 것입니다.

Perl 개발자가 선택한 해법은 (?...)를 확장 문법으로 사용하는 것입니다. 괄호 바로 뒤에 있는 ?는 ?가 반복할 것이 없기 때문에 문법 에러였습니다. 따라서 이것은 어떤 호환성 문제도 일으키지 않습니다. ? 다음에 나오는 문자는 어떤 확장이 사용되는지 나타내므로, (?=foo) 는 한가지 확장이고 (긍정적인 미리 보기 어서션), (?:foo) 는 또 다른 것입니다 (서브 정규식 foo를 포함하는 비 포착 그룹).

파이썬은 여러 Perl의 확장을 지원하고 Perl의 확장 문법에 확장 문법을 추가합니다. 물음표 뒤의 첫 번째 문자가 P이면, 파이썬에 특유한 확장임을 알 수 있습니다.

이제 일반적인 확장 문법을 살펴보았으므로, 복잡한 RE에서 그룹 작업을 단순화하는 기능으로 돌아갈 수 있습니다.

때로 그룹을 사용하여 정규식의 일부를 나타내고 싶지만, 그룹의 내용을 꺼내는 데는 관심이 없습니다. 이 사실을 비 포착 그룹을 사용해서 명시적으로 만들 수 있습니다: (?:...), 여기서 ...을 다른 정규식으로 바꿀 수 있습니다.

>>> m = re.match("([abc])+", "abc")
>>> m.groups()
('c',)
>>> m = re.match("(?:[abc])+", "abc")
>>> m.groups()
()

그룹과 일치하는 내용을 꺼낼 수 없다는 점을 제외하면, 비 포착 그룹은 포착 그룹과 정확히 같게 작동합니다; 안에 어떤 것이든 넣을 수 있고, *와 같은 반복 메타 문자로 반복할 수 있고, 다른 그룹(포착이나 비 포착) 내에 중첩할 수 있습니다. (?:...)는 기존 패턴을 수정할 때 특히 유용합니다. 다른 모든 그룹의 번호가 매겨지는 방식을 변경하지 않고 새 그룹을 추가 할 수 있기 때문입니다. 포착 그룹과 비 포착 그룹을 검색할 때 성능 차이가 없다는 점을 짚고 넘어가야 할 것 같습니다; 두 형태 중 어느 것도 다른 것보다 빠르지 않습니다.

더 중요한 기능은 이름 있는 그룹입니다: 번호로 참조하는 대신, 이름으로 그룹을 참조 할 수 있습니다.

이름 있는 그룹의 문법은 파이썬 특정 확장 중 하나입니다: (?P<name>...). name은, 당연히, 그룹의 이름입니다. 이름 있는 그룹은 포착 그룹과 똑같이 동작하며, 추가로 이름을 그룹과 연관시킵니다. 포착 그룹을 다루는 일치 객체 메서드는 모두 숫자로 그룹을 가리키는 정수나 원하는 그룹의 이름을 포함하는 문자열을 받아들입니다. 이름 있는 그룹에는 여전히 번호가 매겨지므로, 두 가지 방법으로 그룹에 대한 정보를 꺼낼 수 있습니다:

>>> p = re.compile(r'(?P<word>\b\w+\b)')
>>> m = p.search( '(((( Lots of punctuation )))' )
>>> m.group('word')
'Lots'
>>> m.group(1)
'Lots'

또한, groupdict()로 이름 있는 그룹을 딕셔너리로 꺼낼 수 있습니다:

>>> m = re.match(r'(?P<first>\w+) (?P<last>\w+)', 'Jane Doe')
>>> m.groupdict()
{'first': 'Jane', 'last': 'Doe'}

Named groups are handy because they let you use easily remembered names, instead of having to remember numbers. Here’s an example RE from the imaplib module:

InternalDate = re.compile(r'INTERNALDATE "'
        r'(?P<day>[ 123][0-9])-(?P<mon>[A-Z][a-z][a-z])-'
        r'(?P<year>[0-9][0-9][0-9][0-9])'
        r' (?P<hour>[0-9][0-9]):(?P<min>[0-9][0-9]):(?P<sec>[0-9][0-9])'
        r' (?P<zonen>[-+])(?P<zoneh>[0-9][0-9])(?P<zonem>[0-9][0-9])'
        r'"')

그룹 9를 꺼내는 것을 기억하는 대신, m.group('zonem')을 꺼내기가 훨씬 쉽습니다.

(...)\1과 같은 정규식에서 역참조 문법은 그룹 번호를 나타냅니다. 자연스럽게 번호 대신 그룹 이름을 사용하는 변형이 있습니다. 이것은 다른 파이썬 확장입니다: (?P=name)은 name이라는 그룹의 내용이 현재 위치에서 다시 일치해야 함을 나타냅니다. 중복된 단어를 찾는 정규식인 \b(\w+)\s+\1\b는 \b(?P<word>\w+)\s+(?P=word)\b로 표현할 수도 있습니다:

>>> p = re.compile(r'\b(?P<word>\w+)\s+(?P=word)\b')
>>> p.search('Paris in the the spring').group()
'the the'

미리 보기 어서션

또 다른 폭이 없는 어서션은 미리 보기 어서션(lookahead assertion)입니다. 미리 보기 어서션은 긍정과 부정 형식 모두 제공되며, 다음과 같이 표시됩니다:

(?=...)

긍정적인 미리 보기 어서션. 포함된 정규식(여기에서는 ...로 표시되었습니다)이 현재 위치에서 성공적으로 일치하면 성공하고, 그렇지 않으면 실패합니다. 그러나, 일단 포함된 정규식이 시도되면, 일치 엔진은 전혀 앞으로 나아가지 않습니다; 어서선이 시작한 곳에서 나머지 패턴을 시도합니다.

(?!...)

부정적인 미리 보기 어서션. 이것은 긍정적인 어서션의 반대입니다; 포함된 정규식이 문자열의 현재 위치에서 일치하지 않으면 성공합니다.

이를 구체적으로 설명하기 위해, 미리 보기가 유용한 경우를 살펴보겠습니다. 파일 이름을 일치시키고 .로 구분된 기본 이름과 확장자로 분리하는 간단한 패턴을 생각해봅시다. 예를 들어, news.rc에서, news는 기본 이름이고 rc는 파일명의 확장자입니다.

이것과 일치하는 패턴은 매우 간단합니다:

.*[.].*$

.는 메타 문자이므로 특수하게 처리해야 하므로, 해당 문자에만 일치하기 위해 문자 클래스 내에 있습니다. 또한 후행 $도 유의하십시오; 나머지 문자열이 확장에 포함되어야 함을 보장하기 위해 추가됩니다. 이 정규식은 foo.bar와 autoexec.bat와 sendmail.cf와 printers.conf와 일치합니다.

자, 문제를 조금 복잡하게 생각해보십시오; 확장자가 bat이 아닌 파일명을 일치시키려면 어떻게 해야 합니까? 몇 가지 잘못된 시도:

.*[.][^b].*$ 위의 첫 번째 시도는 확장자의 첫 번째 문자가 b가 아니도록 요구하여 bat를 제외하려고 시도합니다. 패턴이 foo.bar와도 일치하지 않기 때문에, 이것은 잘못된 것입니다.

.*[.]([^b]..|.[^a].|..[^t])$

다음에서 하나를 요구하여 첫 번째 해결 방법을 패치할 때 정규식이 더 복잡해집니다: 확장자의 첫 번째 문자가 b가 아닙니다; 두 번째 문자가 a가 아닙니다; 또는 세 번째 문자가 t가 아닙니다. 이것은 foo.bar를 받아들이고 autoexec.bat를 거부하지만, 세 문자 확장자를 요구하고 sendmail.cf와 같은 두 문자로 된 확장자를 가진 파일명을 허용하지 않습니다. 문제를 해결하기 위해 패턴을 다시 복잡하게 만들 것입니다.

.*[.]([^b].?.?|.[^a]?.?|..?[^t]?)$

세 번째 시도에서, sendmail.cf와 같이 세 문자보다 짧은 확장자를 허용하기 위해 두 번째와 세 번째 문자는 모두 선택적입니다.

이제 패턴이 정말 복잡해져서, 읽고 이해하기 어렵습니다. 더욱이, 문제가 변경되어 확장자 bat와 exe를 모두 제외하려면, 패턴이 훨씬 복잡하고 혼란스러워집니다.

부정적인 미리 보기는 이 모든 혼란을 제거합니다:

.*[.](?!bat$)[^.]*$ 부정적인 미리 보기는 다음과 같은 의미입니다: bat 정규식이 이 지점에서 일치하지 않으면, 나머지 패턴을 시도합니다; bat$가 일치하면, 전체 패턴이 실패합니다. 후행 $는 sample.batch와 같이 bat로 시작하기만 하는 확장자를 허용하기 위해 필요합니다. [^.]*는 파일명에 여러 점이 있을 때 패턴이 작동하도록 합니다.

다른 파일명 확장자를 제외하는 것이 이제는 쉽습니다; 단순히 어서션 안에 대안으로 추가하십시오. 다음 패턴은 bat나 exe로 끝나는 파일명을 제외합니다:

.*[.](?!bat$|exe$)[^.]*$

문자열 수정하기

지금까지는, 정적 문자열에 대한 검색만 수행했습니다. 정규식은 다음과 같은 패턴 메서드를 사용하여 다양한 방법으로 문자열을 수정하는 데 흔히 사용됩니다:

메서드/어트리뷰트

목적

split()

RE가 일치하는 모든 곳에서 분할하여, 문자열을 리스트로 분할합니다

sub()

RE가 일치하는 모든 부분 문자열을 찾고, 다른 문자열로 대체합니다.

subn()

sub()와 같은 일을 하지만, 새로운 문자열과 치환 횟수를 반환합니다

문자열 분할하기

패턴의 split() 메서드는 RE가 일치하는 모든 곳에서 문자열을 분할하여, 조각의 리스트를 반환합니다. 이것은 split() 문자열 메서드와 비슷하지만 분리하는 데 사용되는 구분자에 훨씬 더 일반성을 제공합니다; 문자열 split()는 공백이나 고정 문자열로의 분할 만 지원합니다. 예상대로, 모듈 수준의 re.split() 함수도 있습니다.

.split(string[, maxsplit=0])

정규식과 일치하는 것으로 string을 분할합니다. RE에서 포착하는 괄호가 사용되면, 해당 내용도 결과 리스트의 일부로 반환됩니다. maxsplit가 0이 아니면, 최대 maxsplit 번 분할만 수행됩니다.

maxsplit 값을 전달하여, 분할 수를 제한 할 수 있습니다. maxsplit가 0이 아니면, 최대 maxsplit 번 분할만 이루어지고, 나머지 문자열은 리스트의 마지막 요소로 반환됩니다. 다음 예제에서, 구분자는 영숫자가 아닌 문자 시퀀스입니다.

>>> p = re.compile(r'\W+')
>>> p.split('This is a test, short and sweet, of split().')
['This', 'is', 'a', 'test', 'short', 'and', 'sweet', 'of', 'split', '']
>>> p.split('This is a test, short and sweet, of split().', 3)
['This', 'is', 'a', 'test, short and sweet, of split().']

때로는 구분자 사이의 텍스트가 무엇인지에 관심이 있을 뿐만 아니라, 구분자가 무엇인지도 알아야 할 필요가 있습니다. RE에서 포착하는 괄호가 사용되면, 해당 값도 리스트의 일부로 반환됩니다. 다음 호출을 비교하십시오:

>>> p = re.compile(r'\W+')
>>> p2 = re.compile(r'(\W+)')
>>> p.split('This... is a test.')
['This', 'is', 'a', 'test', '']
>>> p2.split('This... is a test.')
['This', '... ', 'is', ' ', 'a', ' ', 'test', '.', '']

모듈 수준 함수 re.split()는 첫 번째 인자로 사용할 RE를 추가하지만, 이를 제외하고는 같습니다.

>>> re.split(r'[\W]+', 'Words, words, words.')
['Words', 'words', 'words', '']
>>> re.split(r'([\W]+)', 'Words, words, words.')
['Words', ', ', 'words', ', ', 'words', '.', '']
>>> re.split(r'[\W]+', 'Words, words, words.', 1)
['Words', 'words, words.']

검색과 치환

또 다른 흔한 작업은 패턴에 대한 모든 일치를 찾아 다른 문자열로 치환하는 것입니다. sub() 메서드는 치환 값(문자열이나 함수일 수 있습니다)과 처리할 문자열을 취합니다.

.sub(replacement, string[, count=0])

string에서 가장 왼쪽에 나타나는 겹쳐지지 않은 RE의 일치를 replacement로 치환한 문자열을 반환합니다. 패턴이 없으면, string이 변경 없이 반환됩니다.

선택적 인자 count는 치환될 패턴 일치의 최대 수입니다; count는 음수가 아닌 정수여야 합니다. 기본값 0은 모든 일치를 치환하는 것을 의미합니다.

다음은 sub() 메서드를 사용하는 간단한 예제입니다. 색상 이름을 colour라는 단어로 바꿉니다:

>>> p = re.compile('(blue|white|red)')
>>> p.sub('colour', 'blue socks and red shoes')
'colour socks and colour shoes'
>>> p.sub('colour', 'blue socks and red shoes', count=1)
'colour socks and red shoes'

subn() 메서드는 같은 작업을 수행하지만, 새 문자열 값과 수행된 치환 수가 포함된 2-튜플을 반환합니다:

>>> p = re.compile('(blue|white|red)')
>>> p.subn('colour', 'blue socks and red shoes')
('colour socks and colour shoes', 2)
>>> p.subn('colour', 'no colours at all')
('no colours at all', 0)

빈 일치는 이전의 빈 일치와 인접하지 않은 경우에만 치환됩니다.

>>> p = re.compile('x*')
>>> p.sub('-', 'abxd')
'-a-b--d-'

replacement가 문자열이면, 그 안에 있는 모든 역 슬래시 이스케이프가 처리됩니다. 즉, \n은 단일 개행 문자로 변환되고, \r은 캐리지 리턴으로 변환되고, 나머지도 마찬가지입니다. \&와 같은 알 수 없는 이스케이프는 그대로 남습니다. \6과 같은 역참조는 RE의 해당 그룹과 일치하는 부분 문자열로 치환됩니다. 이렇게 하면 결과 치환 문자열에 원본 텍스트의 일부를 통합할 수 있습니다.

이 예제는 뒤에 {, }로 묶인 문자열이 오는 단어 section과 일치하고, section을 subsection으로 변경합니다:

>>> p = re.compile('section{ ( [^}]* ) }', re.VERBOSE)
>>> p.sub(r'subsection{\1}','section{First} section{second}')
'subsection{First} subsection{second}'

또한 (?P<name>...) 문법으로 정의된 이름 있는 그룹을 참조하기 위한 문법이 있습니다. \g<name>은 name 그룹과 일치하는 부분 문자열을 사용하고, \g<number>는 해당 그룹 번호를 사용합니다. 따라서 \g<2>는 \2와 동등하지만, \g<2>0과 같은 치환 문자열에서 모호하지 않습니다. (\20은 '0'이 뒤에 오는 그룹 2에 대한 참조가 아닌, 그룹 20에 대한 참조로 해석됩니다.) 다음 치환은 모두 동등하지만, 치환 문자열의 세 가지 변형을 모두 사용합니다.

>>> p = re.compile('section{ (?P<name> [^}]* ) }', re.VERBOSE)
>>> p.sub(r'subsection{\1}','section{First}')
'subsection{First}'
>>> p.sub(r'subsection{\g<1>}','section{First}')
'subsection{First}'
>>> p.sub(r'subsection{\g<name>}','section{First}')
'subsection{First}'

replacement는 함수일 수도 있는데, 더 많은 제어를 제공합니다. replacement가 함수면, pattern의 겹쳐지지 않는 모든 일치에 대해 함수가 호출됩니다. 각 호출에서, 함수는 그 일치에 대한 일치 객체 인자를 전달받고, 이 정보를 사용하여 원하는 치환 문자열을 계산하고 이를 반환 할 수 있습니다.

다음 예제에서, 치환 함수는 십진수를 16진수로 변환합니다:

>>> def hexrepl(match):
...     "Return the hex string for a decimal number"
...     value = int(match.group())
...     return hex(value)
...
>>> p = re.compile(r'\d+')
>>> p.sub(hexrepl, 'Call 65490 for printing, 49152 for user code.')
'Call 0xffd2 for printing, 0xc000 for user code.'

모듈 수준의 re.sub() 함수를 사용할 때, 패턴은 첫 번째 인자로 전달됩니다. 패턴은 객체나 문자열로 제공될 수 있습니다; 정규식 플래그를 지정해야 하면, 패턴 객체를 첫 번째 매개 변수로 사용하거나 패턴 문자열에 포함된 수정자를 사용해야 합니다, 예를 들어 sub("(?i)b+", "x", "bbbb BBBB")는 'x x'를 반환합니다.

일반적인 문제들

정규식은 일부 응용을 위한 강력한 도구이지만, 어떤 면에서는 동작이 직관적이지 않고 때때로 예상대로 동작하지 않을 수도 있습니다. 이 절에서는 가장 일반적인 함정 중 일부를 지적합니다.

문자열 메서드를 사용하십시오

때때로 re 모듈을 사용하는 것은 실수입니다. 고정된 문자열이나 단일 문자 클래스와 일치시키려고 하고, IGNORECASE 플래그와 같은 re 기능을 사용하지 않는다면, 정규식의 모든 기능이 필요하지 않을 수 있습니다. 문자열은 고정 문자열을 사용하는 연산을 수행하는 몇 가지 메서드를 가지고 있으며, 대개 훨씬 빠릅니다. 더 크고, 더 일반화된 정규식 엔진 대신, 구현이 목적에 맞게 최적화된 단일하고 작은 C 루프이기 때문입니다.

한가지 예는 하나의 고정 된 문자열을 다른 것으로 치환하는 것일 수 있습니다; 예를 들어, word를 deed로 바꿀 수 있습니다. re.sub()가 이를 위한 함수인 것처럼 보이지만, replace() 메서드를 고려하십시오. replace()는 또한 단어 안에 있는 word를 치환해서, swordfish를 sdeedfish로 바꾸지만, 나이브한 RE word도 그렇게 했을 것입니다. (단어의 일부에 대한 치환을 수행하는 것을 피하고자, 패턴은 word 양쪽에 단어 경계가 있도록 \bword\b여야 합니다. 이 작업은 replace()의 능력을 넘어섭니다.)

또 다른 일반적인 작업은 문자열에서 단일 문자를 모두 삭제하거나 다른 단일 문자로 바꾸는 것입니다. re.sub('\n', ' ', S)와 같은 방식으로 이 작업을 수행 할 수 있지만, translate()는 두 가지 작업을 모두 수행 할 수 있으며 정규식 연산보다 빠릅니다.

정리하면, re 모듈을 사용하기 전에, 더 빠르고 간단한 문자열 메서드로 문제를 해결할 수 있는지 고려하십시오.

match()와 search() 비교

match() 함수는 문자열 시작 부분에서 RE가 일치하는지만 확인하는 반면, search()는 일치를 찾기 위해 문자열을 정방향으로 검색합니다. 이 차이를 염두에 두는 것이 중요합니다. 기억하십시오, match()는 0에서 시작하는 성공적인 일치만을 보고합니다; 일치가 0에서 시작하지 않으면, match()는 이를 보고하지 않습니다.

>>> print(re.match('super', 'superstition').span())
(0, 5)
>>> print(re.match('super', 'insuperable'))
None

반면에, search()는 문자열을 정방향으로 검색하여, 발견된 첫 번째 일치를 보고합니다.

>>> print(re.search('super', 'superstition').span())
(0, 5)
>>> print(re.search('super', 'insuperable').span())
(2, 7)

때로 re.match()를 계속 사용하면서, 단지 .*를 RE 앞에 추가하고 싶을 수 있습니다. 이 유혹에 저항하고, 대신 re.search()를 사용하십시오. 정규식 컴파일러는 일치를 찾는 프로세스의 속도를 높이기 위해 RE에 대한 분석을 수행합니다. 그러한 분석의 하나는 일치의 첫 번째 문자가 무엇인지 알아내는 것입니다; 예를 들어, Crow로 시작하는 패턴은 'C'로 시작하는 것과 일치해야 합니다. 이 분석을 통해 엔진은 시작 문자를 찾기 위해 문자열을 빠르게 검색하고, 'C'가 발견될 때만 전체 일치를 시도합니다.

.*를 추가하면 이 최적화가 실패하고, 문자열의 끝부분까지 스캔한 다음, RE의 나머지에 대한 일치를 찾기 위해 역 추적합니다. 대신 re.search()를 사용하십시오.

탐욕적 과 비 탐욕적 비교

a*에서와같이 정규식을 반복할 때, 결과 동작은 가능한 한 많은 패턴을 소비하는 것입니다. 이 사실은 HTML 태그를 둘러싼 화살 괄호(angle brackets)와 같이 쌍을 이루는 구분 기호 쌍을 일치시키려고 할 때 여러분을 물어뜯을 수 있습니다. 하나의 HTML 태그를 일치하는 나이브한 패턴은 .*의 탐욕스러운 성격 때문에 작동하지 않습니다.

>>> s = '<html><head><title>Title</title>'
>>> len(s)
32
>>> print(re.match('<.*>', s).span())
(0, 32)
>>> print(re.match('<.*>', s).group())
<html><head><title>Title</title>

RE는 '<html>'의 '<'와 일치하고, .*는 나머지 문자열을 소비합니다. RE에는 여전히 남아있는 것이 있고, >는 문자열의 끝에서 일치할 수 없기 때문에, 정규식 엔진은 >와 일치하는 것을 찾을 때까지 문자 단위로 역 추적해야 합니다. 최종 일치는 '<html>'의 '<'에서 '</title>'의 '>'까지 확장되는데, 이는 여러분이 원하는 것이 아닙니다.

In this case, the solution is to use the non-greedy quantifiers *?, +?, ??, or {m,n}?, which match as little text as possible. In the above example, the '>' is tried immediately after the first '<' matches, and when it fails, the engine advances a character at a time, retrying the '>' at every step. This produces just the right result:

>>> print(re.match('<.*?>', s).group())
<html>

(정규식으로 HTML이나 XML을 구문 분석하기는 쉽지 않습니다. 빠르지만 지저분한 패턴은 일반적인 경우를 처리할 것이지만, HTML과 XML에는 명확한 정규식을 깨뜨릴 특수 사례가 있습니다; 모든 가능한 경우를 처리하도록 정규식을 작성하면, 패턴이 아주 복잡해질 수 있습니다. 이러한 작업에는 HTML이나 XML 구문 분석 모듈을 사용하십시오.)

re.VERBOSE 사용하기

지금까지 정규식이 매우 콤팩트한 표기법이라는 사실을 눈치챘을 것입니다만, 극단적으로 읽기 어렵지는 않았습니다. 중간 정도의 복잡성을 가진 RE는 역 슬래시, 괄호 및 메타 문자의 긴 모음이 되어 읽고 이해하기 어려울 수 있습니다.

이러한 RE의 경우, 정규식을 컴파일할 때 re.VERBOSE 플래그를 지정하면 정규식을 보다 명확하게 포맷할 수 있어서 도움이 됩니다.

re.VERBOSE 플래그는 여러 가지 효과가 있습니다. 문자 클래스 안에 있지 않은 공백이 무시됩니다. 이것은, dog | cat과 같은 정규식은 가독성이 떨어지는 dog|cat과 동등하지만, [a b]는 여전히 'a', 'b' 또는 스페이스 문자와 일치함을 뜻합니다. 또한, 주석을 RE에 넣을 수도 있습니다; 주석은 # 문자에서 다음 줄 바꿈까지 확장됩니다. 삼중 따옴표로 묶은 문자열과 함께 사용하면, RE를 더 깔끔하게 포맷할 수 있습니다:

pat = re.compile(r"""
 \s*                 # Skip leading whitespace
 (?P<header>[^:]+)   # Header name
 \s* :               # Whitespace, and a colon
 (?P<value>.*?)      # The header's value -- *? used to
                     # lose the following trailing whitespace
 \s*$                # Trailing whitespace to end-of-line
""", re.VERBOSE)

이것이 다음보다 훨씬 읽기 쉽습니다:

pat = re.compile(r"\s*(?P<header>[^:]+)\s*:(?P<value>.*?)\s*$")

피드백

정규식은 복잡한 주제입니다. 이 문서가 도움이 되었습니까? 불분명 한 부분이 있거나, 여기에서 다루지 않은 문제가 있습니까? 그렇다면 저자에게 개선을 위한 제안을 보내주십시오.

정규식에 대한 가장 완벽한 책은 거의 확실히 O’Reilly가 출판한 Jeffrey Friedl의 Mastering Regular Expressions 입니다. 불행히도, 이 책은 Perl과 Java의 정규식에만 집중하고, 파이썬 자료를 전혀 포함하지 않아서 파이썬 프로그래밍에 대한 참조로는 유용하지 않습니다. (첫 번째 판은 지금은 제거된 파이썬의 regex 모듈을 다뤘습니다만, 큰 도움은 되지 못합니다.) 여러분의 도서관에서 확인해보십시오.

소켓 프로그래밍 HOWTO

저자:

Gordon McMillan

개요

소켓은 거의 모든 곳에서 사용되지만, 가장 심하게 오해된 기술 중 하나입니다. 이것은 10,000피트 상공에서 본 소켓 개요입니다. 진짜 자습서는 아닙니다 - 여러분은 여전히 작동하도록 만들기 위해 해야 할 일이 있습니다. 세부 사항을 다루지는 않습니다만 (그것 것들이 많이 있습니다), 그것들을 적당히 사용하기에 충분한 배경을 줄 수 있기를 바랍니다.

소켓

INET (즉, IPv4) 소켓에 관해서만 이야기할 것이지만, 사용 중인 소켓의 99% 이상을 차지합니다. 또한, STREAM (즉, TCP) 소켓에 관해서만 이야기할 것입니다 - 여러분이 무엇을 하고 있는지 정말로 알고 있지 (그럴 때 이 HOWTO는 필요 없습니다!) 않다면, 다른 모든 것보다 STREAM 소켓으로 더 나은 동작과 성능을 얻을 수 있습니다. 소켓이 무엇인지에 대한 수수께끼뿐만 아니라 블로킹과 비 블로킹 소켓으로 작업하는 방법에 대한 힌트를 분명하게 하려고 합니다. 하지만 블로킹 소켓에 관해 이야기하는 것으로 시작할 것입니다. 비 블로킹 소켓을 다루기 전에 이것이 어떻게 작동하는지 알아야 합니다.

이러한 것들을 이해하는데 어려움을 주는 한 부분은 문맥에 따라 “소켓”이 여러 가지 미묘하게 다른 것을 뜻할 수 있다는 것입니다. 그래서 먼저, 대화의 끝점인 “클라이언트” 소켓과, 배전반 운영자와 비슷한 “서버” 소켓을 구별해 보겠습니다. 클라이언트 응용 프로그램(예를 들어, 여러분의 브라우저)은 “클라이언트” 소켓만 사용합니다; 이것이 대화하는 웹 서버는 “서버” 소켓과 “클라이언트” 소켓을 모두 사용합니다.

역사

IPC의 다양한 형태 중에서, 소켓이 가장 많이 사용됩니다. 특정 플랫폼에서 다른 형태의 IPC가 더 빠를 가능성이 있지만, 크로스 플랫폼 통신의 경우 소켓이 유일한 게임의 법칙입니다.

They were invented in Berkeley as part of the BSD flavor of Unix. They spread like wildfire with the internet. With good reason — the combination of sockets with INET makes talking to arbitrary machines around the world unbelievably easy (at least compared to other schemes).

소켓 만들기

대충 말하면, 이 페이지로 연결되는 링크를 클릭하면 브라우저가 다음과 같은 작업을 수행합니다:

# create an INET, STREAMing socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# now connect to the web server on port 80 - the normal http port
s.connect(("www.python.org", 80))

connect가 완료되면, 소켓 s를 사용하여 페이지의 텍스트 요청을 보낼 수 있습니다. 같은 소켓으로 응답을 읽은 다음 파괴됩니다. 그렇습니다, 파괴됩니다. 클라이언트 소켓은 일반적으로 하나의 교환(또는 일련의 작은 교환 집합)에서만 사용됩니다.

웹 서버에서 일어나는 일은 좀 더 복잡합니다. 첫째, 웹 서버는 “서버 소켓”을 만듭니다:

# create an INET, STREAMing socket
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# bind the socket to a public host, and a well-known port
serversocket.bind((socket.gethostname(), 80))
# become a server socket
serversocket.listen(5)

알아 두어야 할 몇 가지 사항: 소켓을 외부 세계에서 볼 수 있도록 socket.gethostname()를 사용했습니다. s.bind(('localhost', 80)) 이나 s.bind(('127.0.0.1', 80))을 사용했다면, 여전히 “서버” 소켓을 가지게 되지만 같은 기계 내에서만 볼 수 있는 소켓을 갖게 됩니다. s.bind(('', 80))은 시스템에 있는 모든 주소로 소켓에 연결할 수 있음을 나타냅니다.

두 번째로 주목해야 할 점: 낮은 번호의 포트는 일반적으로 “잘 알려진” 서비스(HTTP, SNMP 등)를 위해 예약되어 있습니다. 연습 중이라면 적당히 높은 번호(4 자릿수)를 사용하십시오.

마지막으로, listen에 대한 인자는 외부 연결을 거부하기 전에 최대 5개의 연결 요청을 큐에 넣기를 원한다는 것을 소켓 라이브러리에 알립니다. 코드의 나머지 부분이 제대로 작성되었다면, 이것으로 충분합니다.

이제 우리는 포트 80에서 대기하는 “서버” 소켓을 가지고 있고, 웹 서버의 메인 루프를 입력할 수 있습니다:

while True:
    # accept connections from outside
    (clientsocket, address) = serversocket.accept()
    # now do something with the clientsocket
    # in this case, we'll pretend this is a threaded server
    ct = make_client_thread(clientsocket)
    ct.start()

실제로 이 루프가 작동할 수 있는 3가지 일반적인 방법이 있습니다 - clientsocket를 처리하기 위해 스레드로 보내거나, clientsocket를 처리할 새 프로세스를 만들거나, 비 블로킹 소켓을 사용하도록 이 응용 프로그램을 재구성하고, select를 사용하여 “서버” 소켓과 활성 clientsocket들 간에 다중화(multiplexing)합니다. 나중에 자세히 다룹니다. 지금 이해해야 할 중요한 점: 이것이 “서버” 소켓이 하는 전부입니다. 어떤 데이터도 보내지 않습니다. 어떤 데이터도 수신하지 않습니다. 단지 “클라이언트” 소켓을 생성할 뿐입니다. 각 clientsocket은 우리가 바인드 한 호스트와 포트로 connect()를 수행하는 다른 “클라이언트” 소켓에 대한 응답으로 만들어집니다. clientsocket를 만들자마자, 더 많은 연결을 기다리는 것으로 돌아갑니다. 두 개의 “클라이언트” 는 자유롭게 대화를 나눌 수 있습니다 - 그들은 대화를 끝낼 때 재활용되는 어떤 동적으로 할당된 포트를 사용합니다.

IPC

한 기계의 두 프로세스 간에 빠른 IPC가 필요하다면, 파이프나 공유 메모리를 살펴야 합니다. AF_INET 소켓을 사용하기로 했다면, “서버” 소켓을 'localhost'에 바인드 하십시오. 대부분 플랫폼에서, 이것은 네트워크 코드의 두어 개의 계층을 건너뛰는 지름길을 취할 것이고, 꽤 빨라집니다.

더 보기

multiprocessing은 교차 플랫폼 IPC를 고수준 API로 통합합니다.

소켓 사용하기

첫 번째로 주목해야 할 점은 웹 브라우저의 “클라이언트” 소켓과 웹 서버의 “클라이언트” 소켓은 같은 녀석이라는 것입니다. 즉, 이것은 “피어 투 피어(peer to peer)” 대화입니다. 또는 다른 방식으로 표현하면, 설계자로서, 대화를 위한 예절의 규칙이 무엇인지 결정해야 합니다. 일반적으로, connect하는 소켓이 요청이나 로그인을 보내 대화를 시작합니다. 그러나 이것은 설계상의 결정입니다 - 소켓의 규칙이 아닙니다.

이제 통신에 사용할 두 벌의 동사가 있습니다. send와 recv를 사용하거나, 클라이언트 소켓을 파일류로 변환한 후 read와 write를 사용할 수 있습니다. 후자는 자바가 소켓을 제공하는 방식입니다. flush를 소켓에 사용해야 한다고 경고하는 것 외에는, 여기에 대해서는 언급하지 않을 것입니다. 이것들은 버퍼 된 “파일”이며, 일반적인 실수는 어떤 것을 write하고는 응답을 read하는 것입니다. flush가 없으면, 요청이 여전히 출력 버퍼에 남아있을 수 있으므로 응답을 영원히 기다리게 될 수 있습니다.

이제 소켓의 주요 걸림돌에 도달했습니다 - send와 recv는 네트워크 버퍼에서 작동합니다. 이것들은 여러분이 넘겨준 모든 바이트를 처리하지 않을 수 있습니다, 그들의 주 관심사는 네트워크 버퍼를 처리하는 것이기 때문입니다. 일반적으로, 연관된 네트워크 버퍼가 채워지거나(send) 비워지면(recv) 반환됩니다. 그런 다음 처리 한 바이트 수를 알려줍니다. 메시지가 완전히 처리될 때까지 다시 호출하는 것은 여러분의 책임입니다.

recv가 0바이트를 반환하면, 다른 쪽이 연결을 닫았거나 닫고 있다는 뜻입니다. 이 연결에서 더는 데이터를 받지 못합니다. 영원히. 데이터를 성공적으로 보낼 수는 있습니다; 나중에 이것에 대해 더 이야기하겠습니다.

HTTP와 같은 프로토콜은 하나의 전송에만 소켓을 사용합니다. 클라이언트는 요청을 보낸 다음 응답을 읽습니다. 그게 전부입니다. 소켓은 버려집니다. 이는 클라이언트가 0바이트를 수신하여 응답의 끝을 감지할 수 있음을 뜻합니다.

그러나 추가 전송을 위해 소켓을 재사용할 계획이라면, 소켓에는 EOT 가 없다는 것을 알아야 합니다. 반복합니다: 소켓 send 또는 recv가 0바이트를 처리한 후 반환되면 연결이 끊어진 것입니다. 연결이 끊어진 것이 아니라면, 소켓은 (당분간) 읽을 것이 아무것도 없다는 것을 알려주지 않을 것이므로, recv에서 영원히 기다릴 수 있습니다. 이것에 대해 조금 더 생각해보면, 소켓의 근본적인 진실을 깨닫게 될 것입니다: 메시지는 고정 길이거나 (억), 구분자로 표시되거나 (어깨를 으쓱), 얼마나 긴지 표시하거나 (훨씬 낫다), 연결을 닫아서 끝내야 합니다. 선택은 전적으로 여러분의 것입니다, (하지만 어떤 방법이 다른 것보다 올바릅니다).

연결을 끝내기를 원하지 않는다고 가정하면, 가장 간단한 해결책은 고정 길이 메시지입니다:

class MySocket:
    """demonstration class only
      - coded for clarity, not efficiency
    """

    def __init__(self, sock=None):
        if sock is None:
            self.sock = socket.socket(
                            socket.AF_INET, socket.SOCK_STREAM)
        else:
            self.sock = sock

    def connect(self, host, port):
        self.sock.connect((host, port))

    def mysend(self, msg):
        totalsent = 0
        while totalsent < MSGLEN:
            sent = self.sock.send(msg[totalsent:])
            if sent == 0:
                raise RuntimeError("socket connection broken")
            totalsent = totalsent + sent

    def myreceive(self):
        chunks = []
        bytes_recd = 0
        while bytes_recd < MSGLEN:
            chunk = self.sock.recv(min(MSGLEN - bytes_recd, 2048))
            if chunk == b'':
                raise RuntimeError("socket connection broken")
            chunks.append(chunk)
            bytes_recd = bytes_recd + len(chunk)
        return b''.join(chunks)

여기에 있는 전송 코드는 거의 모든 메시지전달 체계에서 사용할 수 있습니다 - 파이썬에서는 문자열을 보내고 len()를 사용하여 길이를 파악할 수 있습니다 (\0 문자가 포함되어 있어도). 더 복잡한 부분은 대부분 수신 코드입니다. (그리고 C에서도, 메시지가 \0을 포함하고 있을 때 strlen을 사용할 수 없다는 점을 제외하면 몹시 나쁘지는 않습니다.)

가장 쉬운 개선은 메시지의 첫 번째 문자를 메시지 유형의 표시자로 만들고, 유형이 길이를 결정하도록 하는 것입니다. 이제 두 개의 recv가 있습니다 - (적어도) 첫 번째 문자를 가져와서 길이를 조회할 수 있도록 하는 첫 번째와 나머지를 얻는 루프로 구성된 두 번째입니다. 구분자로 가기로 했다면, 임의의 청크 크기(4096이나 8192는 네트워크 버퍼 크기와 종종 잘 맞습니다)로 수신하고 받은 내용에서 구분자를 검색하게 될 것입니다.

하나의 복잡성을 알아 두어야 합니다: 여러분의 대화형 프로토콜이 (어떤 종류의 응답 없이) 여러 메시지를 연속적으로 보내는 것을 허락하고, recv에 임의의 청크 크기를 전달하면 다음 메시지의 시작 부분도 함께 읽는 일이 일어날 수 있습니다. 필요할 때까지 보관해 두어야 합니다.

메시지의 길이를 앞에 붙이면 (5자리 숫자라고 합시다) 더 복잡해집니다, (믿거나 말거나) 한 번의 recv로 5문자를 모두 얻을 수 없을 수 있기 때문입니다. 연습 중에는 이런 일이 일어나지 않을 것입니다; 하지만 네트워크 로드가 높으면, 두 개의 recv 루프를 사용하지 않는 한 여러분의 코드는 금방 망가지게 됩니다 - 길이를 결정하는 첫 번째와 메시지의 데이터 부분을 가져오는 두 번째입니다. 지저분합니다. 또한 send가 항상 한 번에 모든 것을 처리하지 못하는 것을 발견하게 될 것입니다. 그리고 이 단락을 읽었음에도, 결국 당신은 이 문제에 당하게 될 것입니다!

공간을 절약하고, 여러분의 성격을 단련하고, (그리고 제 경쟁적 지위를 유지하기 위해) 이러한 향상은 독자를 위한 연습으로 남겨둡니다. 이제 정리해봅시다.

바이너리 데이터

It is perfectly possible to send binary data over a socket. The major problem is that not all machines use the same formats for binary data. For example, network byte order [https://en.wikipedia.org/wiki/Endianness#Networking] is big-endian, with the most significant byte first, so a 16 bit integer with the value 1 would be the two hex bytes 00 01. However, most common processors (x86/AMD64, ARM, RISC-V), are little-endian, with the least significant byte first - that same 1 would be 01 00.

Socket libraries have calls for converting 16 and 32 bit integers - ntohl, htonl, ntohs, htons where “n” means network and “h” means host, “s” means short and “l” means long. Where network order is host order, these do nothing, but where the machine is byte-reversed, these swap the bytes around appropriately.

In these days of 64-bit machines, the ASCII representation of binary data is frequently smaller than the binary representation. That’s because a surprising amount of the time, most integers have the value 0, or maybe 1. The string "0" would be two bytes, while a full 64-bit integer would be 8. Of course, this doesn’t fit well with fixed-length messages. Decisions, decisions.

연결 끊기

엄밀히 말하면, close를 사용하기 전에 소켓에 shutdown을 사용해야 합니다. shutdown은 반대편 소켓에 대한 권고입니다. 전달하는 인자에 따라, “더는 보내지 않을 것이지만, 여전히 들을 겁니다” 나 “듣고 있지 않습니다, 즐거웠습니다!”를 뜻할 수 있습니다. 그러나, 대부분 소켓 라이브러리는 프로그래머가 이 예절을 무시하는 방식으로 사용되었고 일반적으로 close가 shutdown(); close()와 같습니다. 따라서 대부분 상황에서 명시적인 shutdown은 필요하지 않습니다.

shutdown을 효과적으로 사용하는 한 가지 방법은 HTTP와 비슷한 교환에서입니다. 클라이언트는 요청을 보낸 다음 shutdown(1)을 수행합니다. 그러면 서버에 “이 클라이언트는 전송을 완료했지만 계속 받을 수 있습니다.”라고 말하게 됩니다. 서버는 0바이트의 수신으로 “EOF”를 감지할 수 있습니다. 요청을 완료했다고 가정할 수 있습니다. 서버가 응답을 보냅니다. send가 성공적으로 완료되면, 클라이언트는 여전히 수신 중입니다.

파이썬은 자동 shutdown을 한 걸음 더 나아가서, 소켓이 가비지 수집될 때 필요하면 자동으로 close를 수행한다고 말합니다. 그러나 이것에 의존하는 것은 매우 나쁜 습관입니다. close를 하지 않고 소켓이 사라지면, 반대편 끝은 여러분이 단지 느려지고 있다고 생각하면서 무한정 멈출 수 있습니다. 제발 완료되면 소켓을 close해 주세요.

소켓이 죽을 때

아마도 블로킹 소켓 사용에 관한 최악의 경우는 상대방이 (close를 수행하지 않고) 갑자기 다운되었을 때 일어나는 일입니다. 소켓이 멈출 수 있습니다. TCP는 신뢰성 있는 프로토콜이며, 연결을 포기하기 전에 아주 오랜 시간 동안 기다립니다. 스레드를 사용하고 있다면, 스레드 전체가 실질적으로 죽습니다. 이것에 대해 당신이 할 수 있는 일이 별로 없습니다. 블로킹 읽기를 수행하는 동안 록을 잡는 것과 같은 어리석은 짓을 하지 않는 한, 스레드는 자원을 많이 소비하지 않습니다. 스레드를 죽이려고 하지 마십시오 - 스레드가 프로세스보다 효율적인 부분적인 이유는 자원 재활용과 관련된 오버헤드를 회피한다는 것입니다. 즉, 스레드를 죽이면 전체 프로세스가 엉망이 될 가능성이 있습니다.

비 블로킹 소켓

앞의 내용을 이해했다면 소켓을 사용하는 방법에 대해 알아야 할 대부분을 이미 알고 있습니다. 거의 같은 방식으로 같은 호출을 계속 사용합니다. 여러분이 올바르게 사용하기만 한다면, 여러분의 앱을 거의 완전해질 겁니다.

파이썬에서, socket.setblocking(False)를 사용하여 비 블로킹으로 만듭니다. C에서는, 더 복잡하지만 (한가지 예를 들면, BSD 계열의 O_NONBLOCK과 POSIX 계열의 거의 같은 O_NDELAY 중에서 선택해야 합니다; O_NDELAY는 TCP_NODELAY와는 완전히 다른 것입니다) 똑같은 아이디어입니다. 소켓을 만든 후에, 하지만 사용하기 전에 이것을 수행합니다. (실제로는, 여러분이 괴짜라면, 계속 변경할 수 있습니다.)

동작의 주요 차이점은 send, recv, connect 및 accept가 아무것도 하지 않고 반환될 수 있다는 것입니다. 여러분에게는 (물론) 많은 선택지가 있습니다. 반환 코드와 에러 코드를 확인하면서 일반적으로 자신을 미치게 만들 수 있습니다. 믿기지 않는다면, 한번 시도해보십시오. 여러분의 앱은 커지고, 버그가 많으며 CPU를 소진할 겁니다. 그러니 뇌사에 이르게 할 해결책은 건너뛰고 올바르게 해 봅시다.

select를 사용하십시오.

C에서, select 코딩은 상당히 복잡합니다. 파이썬에서, 이것은 달콤한 조각이지만, 여러분이 파이썬에서 select를 이해한다면 C에서도 거의 문제가 없을 만큼 C 버전에 아주 가깝습니다:

ready_to_read, ready_to_write, in_error = \
               select.select(
                  potential_readers,
                  potential_writers,
                  potential_errs,
                  timeout)

select로 세 개의 리스트를 전달합니다: 첫 번째는 읽으려는 모든 소켓을 포함합니다; 두 번째는 쓰려는 모든 소켓, 그리고 마지막으로 (보통 비어있는데) 에러를 검사하려는 소켓들입니다. 소켓이 둘 이상의 리스트에 들어갈 수 있음에 유의해야 합니다. select 호출은 블로킹이지만, 시간제한을 지정할 수 있습니다. 이것은 일반적으로 민감한 작업입니다 - 달리할 좋은 이유가 없다면 긴 제한 시간(가령 1분)을 주십시오.

반환 값으로, 세 개의 리스트를 얻게 됩니다. 실제로 읽을 수 있고, 쓸 수 있고, 에러가 있는 소켓이 들어있습니다. 이 리스트는 각기 여러분이 전달한 해당 목록의 부분집합(비어있는 것도 가능합니다)입니다.

소켓이 반환된 읽기 가능한 리스트에 있다면, 그 소켓에 대한 recv가 무언가를 반환하리라는 것을 알 수 있습니다. 쓰기 가능한 리스트도 마찬가지입니다. 무언가를 보낼 수 있습니다. 아마 당신이 원하는 전부는 아니겠지만, 무언가는 아무것도 아닌 것보다 낫습니다. (사실, 합리적으로 건강한 소켓은 쓰기 가능 상태로 반환될 것입니다 - 단지 네트워크 송신 버퍼 공간을 사용할 수 있음을 뜻합니다.)

“서버” 소켓이 있다면, potential_readers 리스트에 넣으십시오. 읽기 가능한 리스트에 등장하면, accept가 (거의 확실하게) 작동합니다. 다른 곳으로 connect하는 새 소켓을 만들었으면, potential_writers 리스트에 넣으십시오. 쓰기 가능한 리스트에 등장하면, 연결되었을 확률이 높습니다.

사실, select는 블로킹 소켓에서도 편리할 수 있습니다. 블록 할지 판단하는 한 가지 방법입니다 - 소켓은 버퍼에 무엇인가가 있으면 읽기 가능으로 반환됩니다. 그러나, 이것은 상대방이 완료했는지 아니면 단지 다른 일로 바쁜 것인지를 결정하는 문제에는 여전히 도움이 되지 않습니다.

이식성 경고: 유닉스에서, select는 소켓과 파일 모두에서 작동합니다. 윈도우에서 이런 시도를 하지 마십시오. 윈도우에서 select는 소켓에서만 작동합니다. 또한, C에서 많은 고급 소켓 옵션은 윈도우에서 다르게 동작함에 유의하십시오. 사실, 윈도우에서 저는 보통 소켓에 스레드를 사용합니다 (아주 잘 작동합니다).

Sorting Techniques

저자:

Andrew Dalke와 Raymond Hettinger

파이썬 리스트에는 리스트를 제자리에서(in-place) 수정하는 내장 list.sort() 메서드가 있습니다. 또한, 이터러블로부터 새로운 정렬된 리스트를 만드는 sorted() 내장 함수가 있습니다.

이 문서에서는, 파이썬을 사용하여 데이터를 정렬하는 다양한 기술을 살펴봅니다.

정렬 기초

A simple ascending sort is very easy: just call the sorted() function. It returns a new sorted list:

>>> sorted([5, 2, 3, 1, 4])
[1, 2, 3, 4, 5]

list.sort() 메서드를 사용할 수도 있습니다. 리스트를 제자리에서 수정합니다 (그리고 혼동을 피하고자 None을 반환합니다). 일반적으로 sorted()보다 덜 편리합니다 - 하지만 원래 목록이 필요하지 않다면, 이것이 약간 더 효율적입니다.

>>> a = [5, 2, 3, 1, 4]
>>> a.sort()
>>> a
[1, 2, 3, 4, 5]

또 다른 점은 list.sort() 메서드가 리스트에게만 정의된다는 것입니다. 이와 달리, sorted() 함수는 모든 이터러블을 받아들입니다.

>>> sorted({1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'})
[1, 2, 3, 4, 5]

키 함수

The list.sort() method and the functions sorted(), min(), max(), heapq.nsmallest(), and heapq.nlargest() have a key parameter to specify a function (or other callable) to be called on each list element prior to making comparisons.

For example, here’s a case-insensitive string comparison using str.casefold():

>>> sorted("This is a test string from Andrew".split(), key=str.casefold)
['a', 'Andrew', 'from', 'is', 'string', 'test', 'This']

key 매개 변수의 값은 단일 인자를 취하고 정렬 목적으로 사용할 키를 반환하는 함수(또는 다른 콜러블)여야 합니다. 키 함수가 각 입력 레코드에 대해 정확히 한 번 호출되기 때문에 이 기법은 빠릅니다.

일반적인 패턴은 객체의 인덱스 중 일부를 키로 사용하여 복잡한 객체를 정렬하는 것입니다. 예를 들어:

>>> student_tuples = [
...     ('john', 'A', 15),
...     ('jane', 'B', 12),
...     ('dave', 'B', 10),
... ]
>>> sorted(student_tuples, key=lambda student: student[2])   # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

같은 기법이 이름있는 어트리뷰트를 갖는 객체에서도 작동합니다. 예를 들어:

>>> class Student:
...     def __init__(self, name, grade, age):
...         self.name = name
...         self.grade = grade
...         self.age = age
...     def __repr__(self):
...         return repr((self.name, self.grade, self.age))

>>> student_objects = [
...     Student('john', 'A', 15),
...     Student('jane', 'B', 12),
...     Student('dave', 'B', 10),
... ]
>>> sorted(student_objects, key=lambda student: student.age)   # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

Objects with named attributes can be made by a regular class as shown above, or they can be instances of dataclass or a named tuple.

Operator Module Functions and Partial Function Evaluation

The key function patterns shown above are very common, so Python provides convenience functions to make accessor functions easier and faster. The operator module has itemgetter(), attrgetter(), and a methodcaller() function.

이러한 함수를 사용하면, 위의 예제가 더 간단 해지고 빨라집니다:

>>> from operator import itemgetter, attrgetter

>>> sorted(student_tuples, key=itemgetter(2))
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

>>> sorted(student_objects, key=attrgetter('age'))
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

operator 모듈 함수는 다중 수준의 정렬을 허용합니다. 예를 들어, 먼저 grade로 정렬한 다음 age로 정렬하려면, 이렇게 합니다:

>>> sorted(student_tuples, key=itemgetter(1,2))
[('john', 'A', 15), ('dave', 'B', 10), ('jane', 'B', 12)]

>>> sorted(student_objects, key=attrgetter('grade', 'age'))
[('john', 'A', 15), ('dave', 'B', 10), ('jane', 'B', 12)]

The functools module provides another helpful tool for making key-functions. The partial() function can reduce the arity [https://en.wikipedia.org/wiki/Arity] of a multi-argument function making it suitable for use as a key-function.

>>> from functools import partial
>>> from unicodedata import normalize

>>> names = 'Zoë Åbjørn Núñez Élana Zeke Abe Nubia Eloise'.split()

>>> sorted(names, key=partial(normalize, 'NFD'))
['Abe', 'Åbjørn', 'Eloise', 'Élana', 'Nubia', 'Núñez', 'Zeke', 'Zoë']

>>> sorted(names, key=partial(normalize, 'NFC'))
['Abe', 'Eloise', 'Nubia', 'Núñez', 'Zeke', 'Zoë', 'Åbjørn', 'Élana']

오름차순과 내림차순

list.sort()와 sorted()는 모두 불리언 값을 갖는 reverse 매개 변수를 받아들입니다. 내림차순 정렬을 지정하는 데 사용됩니다. 예를 들어, 학생 데이터를 역 age 순서로 얻으려면, 이렇게 합니다:

>>> sorted(student_tuples, key=itemgetter(2), reverse=True)
[('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

>>> sorted(student_objects, key=attrgetter('age'), reverse=True)
[('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

정렬 안정성과 복잡한 정렬

정렬은 안정적 [https://en.wikipedia.org/wiki/Sorting_algorithm#Stability]임이 보장됩니다. 즉, 여러 레코드가 같은 키를 가질 때, 원래의 순서가 유지됩니다.

>>> data = [('red', 1), ('blue', 1), ('red', 2), ('blue', 2)]
>>> sorted(data, key=itemgetter(0))
[('blue', 1), ('blue', 2), ('red', 1), ('red', 2)]

blue에 대한 두 레코드가 원래 순서를 유지해서 ('blue', 1)이 ('blue', 2)보다 앞에 나옴이 보장됨에 유의하십시오.

이 멋진 속성은 일련의 정렬 단계로 복잡한 정렬을 만들 수 있도록 합니다. 예를 들어, 학생 데이터를 grade의 내림차순으로 정렬한 다음, age의 오름차순으로 정렬하려면, 먼저 age 정렬을 수행한 다음 grade를 사용하여 다시 정렬합니다:

>>> s = sorted(student_objects, key=attrgetter('age'))     # sort on secondary key
>>> sorted(s, key=attrgetter('grade'), reverse=True)       # now sort on primary key, descending
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

이것은 다중 패스로 정렬하기 위해 필드와 순서의 튜플 리스트를 받을 수 있는 래퍼 함수로 추상화할 수 있습니다.

>>> def multisort(xs, specs):
...     for key, reverse in reversed(specs):
...         xs.sort(key=attrgetter(key), reverse=reverse)
...     return xs

>>> multisort(list(student_objects), (('grade', True), ('age', False)))
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

파이썬에서 사용된 Timsort [https://en.wikipedia.org/wiki/Timsort] 알고리즘은 데이터 집합에 이미 존재하는 순서를 활용할 수 있으므로 효율적으로 여러 번의 정렬을 수행합니다.

Decorate-Sort-Undecorate

이 관용구는 그것의 세 단계를 따라 장식-정렬-복원(Decorate-Sort-Undecorate)이라고 합니다:

첫째, 초기 리스트가 정렬 순서를 제어하는 새로운 값으로 장식됩니다.

둘째, 장식된 리스트를 정렬합니다.

마지막으로, 장식을 제거하여, 새 순서로 초깃값만 포함하는 리스트를 만듭니다.

예를 들어, DSU 방식을 사용하여 grade로 학생 데이터를 정렬하려면 다음과 같이 합니다:

>>> decorated = [(student.grade, i, student) for i, student in enumerate(student_objects)]
>>> decorated.sort()
>>> [student for grade, i, student in decorated]               # undecorate
[('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

이 관용구는 튜플이 사전식으로 비교되기 때문에 작동합니다; 첫 번째 항목이 비교됩니다; 그들이 같으면 두 번째 항목이 비교되고, 이런 식으로 계속됩니다.

모든 경우에 장식된 리스트에 인덱스 i를 포함할 필요는 없지만, 두 가지 이점이 있습니다:

정렬이 안정적입니다 – 두 항목이 같은 키를 가지면, 그 들의 순서가 정렬된 리스트에 유지됩니다.

장식된 튜플의 순서는 최대 처음 두 항목에 의해 결정되므로 원래 항목은 비교 가능할 필요가 없습니다. 그래서 예를 들어, 원래 리스트에는 직접 정렬될 수 없는 복소수가 포함될 수 있습니다.

이 관용구의 또 다른 이름은 펄 프로그래머들 사이에서 이것을 대중화한 Randal L. Schwartz의 이름을 딴 Schwartzian 변환 [https://en.wikipedia.org/wiki/Schwartzian_transform]입니다.

이제 파이썬 정렬이 키 함수를 제공하기 때문에, 이 기법은 자주 필요하지 않습니다.

Comparison Functions

Unlike key functions that return an absolute value for sorting, a comparison function computes the relative ordering for two inputs.

For example, a balance scale [https://upload.wikimedia.org/wikipedia/commons/1/17/Balance_à_tabac_1850.JPG] compares two samples giving a relative ordering: lighter, equal, or heavier. Likewise, a comparison function such as cmp(a, b) will return a negative value for less-than, zero if the inputs are equal, or a positive value for greater-than.

It is common to encounter comparison functions when translating algorithms from other languages. Also, some libraries provide comparison functions as part of their API. For example, locale.strcoll() is a comparison function.

To accommodate those situations, Python provides functools.cmp_to_key to wrap the comparison function to make it usable as a key function:

sorted(words, key=cmp_to_key(strcoll))  # locale-aware sort order

Strategies For Unorderable Types and Values

A number of type and value issues can arise when sorting. Here are some strategies that can help:

Convert non-comparable input types to strings prior to sorting:

>>> data = ['twelve', '11', 10]
>>> sorted(map(str, data))
['10', '11', 'twelve']

This is needed because most cross-type comparisons raise a TypeError.

Remove special values prior to sorting:

>>> from math import isnan
>>> from itertools import filterfalse
>>> data = [3.3, float('nan'), 1.1, 2.2]
>>> sorted(filterfalse(isnan, data))
[1.1, 2.2, 3.3]

This is needed because the IEEE-754 standard [https://en.wikipedia.org/wiki/IEEE_754] specifies that, “Every NaN shall compare unordered with everything, including itself.”

Likewise, None can be stripped from datasets as well:

>>> data = [3.3, None, 1.1, 2.2]
>>> sorted(x for x in data if x is not None)
[1.1, 2.2, 3.3]

This is needed because None is not comparable to other types.

Convert mapping types into sorted item lists before sorting:

>>> data = [{'a': 1}, {'b': 2}]
>>> sorted(data, key=lambda d: sorted(d.items()))
[{'a': 1}, {'b': 2}]

This is needed because dict-to-dict comparisons raise a TypeError.

Convert set types into sorted lists before sorting:

>>> data = [{'a', 'b', 'c'}, {'b', 'c', 'd'}]
>>> sorted(map(sorted, data))
[['a', 'b', 'c'], ['b', 'c', 'd']]

This is needed because the elements contained in set types do not have a deterministic order. For example, list({'a', 'b'}) may produce either ['a', 'b'] or ['b', 'a'].

Odds and Ends

For locale aware sorting, use locale.strxfrm() for a key function or locale.strcoll() for a comparison function. This is necessary because “alphabetical” sort orderings can vary across cultures even if the underlying alphabet is the same.

reverse 매개 변수는 여전히 정렬 안정성을 유지합니다 (그래서 같은 키를 갖는 레코드는 원래 순서를 유지합니다). 흥미롭게도, 그 효과는 내장 reversed() 함수를 두 번 사용하여 매개 변수 없이 흉내 낼 수 있습니다:

>>> data = [('red', 1), ('blue', 1), ('red', 2), ('blue', 2)]
>>> standard_way = sorted(data, key=itemgetter(0), reverse=True)
>>> double_reversed = list(reversed(sorted(reversed(data), key=itemgetter(0))))
>>> assert standard_way == double_reversed
>>> standard_way
[('red', 1), ('red', 2), ('blue', 1), ('blue', 2)]

The sort routines use < when making comparisons between two objects. So, it is easy to add a standard sort order to a class by defining an __lt__() method:

>>> Student.__lt__ = lambda self, other: self.age < other.age
>>> sorted(student_objects)
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

However, note that < can fall back to using __gt__() if __lt__() is not implemented (see object.__lt__() for details on the mechanics). To avoid surprises, PEP 8 [https://peps.python.org/pep-0008/] recommends that all six comparison methods be implemented. The total_ordering() decorator is provided to make that task easier.

키 함수는 정렬되는 객체에 직접 의존할 필요가 없습니다. 키 함수는 외부 자원에 액세스할 수도 있습니다. 예를 들어, 학생 성적이 딕셔너리에 저장되어 있다면, 학생 이름의 별도 리스트를 정렬하는 데 사용할 수 있습니다:

>>> students = ['dave', 'john', 'jane']
>>> newgrades = {'john': 'F', 'jane':'A', 'dave': 'C'}
>>> sorted(students, key=newgrades.__getitem__)
['jane', 'dave', 'john']

Partial Sorts

Some applications require only some of the data to be ordered. The standard library provides several tools that do less work than a full sort:

min() and max() return the smallest and largest values, respectively. These functions make a single pass over the input data and require almost no auxiliary memory.

heapq.nsmallest() and heapq.nlargest() return the n smallest and largest values, respectively. These functions make a single pass over the data keeping only n elements in memory at a time. For values of n that are small relative to the number of inputs, these functions make far fewer comparisons than a full sort.

heapq.heappush() and heapq.heappop() create and maintain a partially sorted arrangement of data that keeps the smallest element at position 0. These functions are suitable for implementing priority queues which are commonly used for task scheduling.

유니코드 HOWTO

버전:

1.12

이 HOWTO는 텍스트 데이터를 나타내기 위한 유니코드 명세를 지원하는 파이썬에 대한 설명과 유니코드로 작업할 때 일반적으로 마주하는 다양한 문제들에 관해 설명합니다.

유니코드 소개

정의

오늘날의 프로그램은 다양한 문자를 처리할 수 있어야 합니다. 응용 프로그램은 종종 국제화되어 다양한 사용자 선택 가능한 언어로 메시지를 표시하고 출력합니다; 같은 프로그램이 영어, 프랑스어, 일본어, 히브리어 또는 러시아어로 에러 메시지를 출력해야 할 수 있습니다. 웹 콘텐츠는 이러한 언어로 작성될 수 있으며 다양한 이모티콘 기호를 포함할 수도 있습니다. 파이썬의 문자열형은 문자를 표현하기 위해 유니코드 표준을 사용하므로, 파이썬 프로그램은 가능한 모든 다른 문자로 작업 할 수 있습니다.

유니코드(https://www.unicode.org/)는 인간 언어에서 사용하는 모든 문자를 나열하고 각 문자에 고유한 코드를 부여하고자 하는 명세입니다. 새로운 언어와 기호를 추가하기 위해 유니코드 명세가 계속 개정되고 갱신됩니다.

문자는 텍스트의 가능한 최소 구성요소입니다. ‘A’, ‘B’, ‘C’ 등은 전부 다른 문자입니다. ‘È’와 ‘Í’ 역시 그렇습니다. 문자는 언어나 문맥에 따라 다릅니다. 예를 들어 대문자 ‘I’와는 별개로, “로마 숫자 하나(Roman Numeral One)”를 위한 문자 ‘Ⅰ’가 있습니다. 이들은 보통 똑같아 보이지만, 서로 다른 의미를 가진 두 개의 다른 문자입니다.

유니코드 표준은 문자를 어떻게 코드 포인트로 표현하는지 서술하고 있습니다. 코드 포인트 값은 0에서 0x10FFFF 사이의 정수입니다 (약 110만 개의 값입니다, 할당된 실제 수 [https://www.unicode.org/versions/latest/#Summary]는 이보다 적습니다). 표준과 이 문서에서 코드 포인트는 U+265E 표기법을 사용하며, 이는 값 0x265e(10진수로는 9,822)인 문자를 의미합니다.

유니코드 표준은 문자와 그에 상응하는 코드 포인트를 나열한 수많은 표를 포함하고 있습니다:

0061    'a'; LATIN SMALL LETTER A
0062    'b'; LATIN SMALL LETTER B
0063    'c'; LATIN SMALL LETTER C
...
007B    '{'; LEFT CURLY BRACKET
...
2167    'Ⅷ'; ROMAN NUMERAL EIGHT
2168    'Ⅸ'; ROMAN NUMERAL NINE
...
265E    '♞'; BLACK CHESS KNIGHT
265F    '♟'; BLACK CHESS PAWN
...
1F600   '😀'; GRINNING FACE
1F609   '😉'; WINKING FACE
...

엄밀히 말하자면, 이러한 정의는 ‘이것이 문자 U+265E’라고 말하는 것은 의미가 없음을 뜻합니다. U+265E는 어떤 특정 문자를 표현하는 코드 포인트일 뿐입니다; 이 경우에는 ‘BLACK CHESS KNIGHT’(’♞’)를 나타냅니다. 일상적인 문맥에서 코드 포인트와 문자 사이의 구분은 때때로 잊힐 겁니다.

문자는 화면이나 종이에 글리프라 불리는 그래픽 요소의 집합으로 표시됩니다. 예를 들어 대문자 A의 글리프는 두 개의 대각 획과 한 개의 수평 획이지만, 정확한 세부사항은 글꼴에 따라 다릅니다. 대부분의 파이썬 코드는 글리프를 걱정할 필요가 없습니다; 표시할 올바른 글리프를 찾는 것은 일반적으로 GUI 툴킷이나 터미널의 글꼴 렌더러의 일입니다.

인코딩

이전 섹션 요약: 유니코드 문자열은 코드 포인트의 시퀀스이며, 0부터 0x10FFFF (십진수 1,114,111)의 범위를 갖는 수입니다. 이 코드 포인트의 시퀀스는 메모리에서 코드 단위(code units)의 집합으로 표현될 필요가 있고, 그런 다음 코드 단위는 8비트 바이트로 매핑됩니다. 유니코드 문자열을 바이트 시퀀스로 변환하는 규칙을 문자 인코딩(character encoding), 또는 단지 인코딩(encoding)이라고 부릅니다.

생각할 수 있는 첫 번째 인코딩은 코드 단위로 32비트 정수를 사용한 다음 32비트 정수의 CPU 표현을 사용하는 것입니다. 이 표현에서 문자열 “Python”은 다음과 같습니다:

   P           y           t           h           o           n
0x50 00 00 00 79 00 00 00 74 00 00 00 68 00 00 00 6f 00 00 00 6e 00 00 00
   0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

이 표현은 간단하지만 여러 문제를 가지고 있습니다.

이식성이 없습니다; 다른 프로세서는 바이트를 다르게 정렬합니다.

이는 공간을 매우 낭비하는 겁니다. 대부분 텍스트에서 주요 코드 포인트는 127 또는 255보다 작으므로 많은 공간이 0x00으로 채워집니다. 위의 문자열은 ASCII 표현에 필요한 6 바이트와 비교하여 24 바이트를 사용합니다. 늘어난 RAM 사용은 중요하지 않지만(데스크톱 컴퓨터는 기가바이트 단위의 RAM을 갖고 있고, 문자열은 대개 그 정도로 크지 않습니다), 디스크와 네트워크 대역폭 사용을 4배로 확장하는 것은 용납할 수 없습니다.

strlen()과 같은 기존의 C 함수와 호환이 안 되기 때문에 새로운 와이드 문자열 함수 계열을 사용해야 합니다.

따라서 이 인코딩은 많이 사용되지 않으며, 사람들은 UTF-8과 같은 더 효율적이고 편리한 다른 인코딩을 선택합니다.

UTF-8은 일반적으로 가장 많이 사용되는 인코딩 중 하나이고, 파이썬은 종종 기본적으로 이것을 사용합니다. UTF는 “Unicode Transformation Format”의 약자이며 ‘8’은 8비트 값이 인코딩에 사용됨을 뜻합니다. (UTF-16과 UTF-32 인코딩도 있지만, UTF-8보다 낮은 빈도로 사용됩니다.) UTF-8은 다음의 규칙을 따릅니다:

만약 코드 포인트가 128보다 작다면, 해당 바이트 값으로 표현됩니다.

만약 코드 포인트가 128보다 크거나 같다면, 시퀀스의 각 바이트가 128에서 255 사이인 둘, 셋 또는 네 개의 바이트 시퀀스로 바뀝니다.

UTF-8은 몇 가지 편리한 특징이 있습니다:

모든 유니코드 코드 포인트를 처리 할 수 있습니다.

유니코드 문자열은 널 문자를 표현하는 곳에만 내장된 0바이트를 포함하는 바이트 시퀀스로 변환됩니다. 이는 UTF-8 문자열을 strcpy()와 같은 C 함수로 처리하고 문자열 끝 표시 이외의 0바이트를 처리하지 못하는 프로토콜을 통해 전송할 수 있음을 의미합니다.

ASCII 텍스트의 문자열 역시 유효한 UTF-8 텍스트입니다.

UTF-8은 꽤 알찹니다; 일반적으로 사용되는 문자 대부분을 한두 개의 바이트로 표현할 수 있습니다.

만약 바이트가 손상 또는 손실되었다면, 다음 UTF-8 인코딩 코드 포인트의 시작을 결정하고 다시 동기화할 수 있습니다. 무작위 8비트 데이터가 유효한 UTF-8처럼 보일 가능성은 낮습니다.

UTF-8은 바이트 지향 인코딩입니다. 인코딩은 각 문자가 하나 이상의 바이트의 특정 시퀀스로 표시되도록 지정합니다. 이렇게 하면 UTF-16과 UTF-32와 같이 바이트의 시퀀스가 문자열이 인코딩된 하드웨어에 따라 달라지는 정수와 워드(word) 지향 인코딩에서 발생할 수 있는 바이트 순서 문제를 피할 수 있습니다.

참조

유니코드 컨소시엄 사이트 [https://www.unicode.org]는 유니코드 사양의 문자 차트, 용어집 그리고 PDF 버전의 유니코드 명세를 갖고 있습니다. 어려운 읽기를 준비하세요. 유니코드의 기원과 개발의 연대기 [https://www.unicode.org/history/] 역시 이 사이트에서 볼 수 있습니다.

Computerphile 유튜브 채널에서, Tom Scott가 간략하게 유니코드와 UTF-8의 역사를 논의합니다 [https://www.youtube.com/watch?v=MijmeoH9LT4] (9분 36초).

To help understand the standard, Jukka Korpela has written an introductory guide [https://jkorpela.fi/unicode/guide.html] to reading the Unicode character tables.

또 다른 좋은 입문 글 [https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/]을 Joel Spolsky가 썼습니다. 이 입문서로도 명확하지 않은 경우 계속하기 전에 이 대체 문서를 읽으세요.

위키피디아 항목은 때때로 도움이 됩니다; 예를 들어, “문자 인코딩 [https://en.wikipedia.org/wiki/Character_encoding]”과 UTF-8 [https://en.wikipedia.org/wiki/UTF-8] 항목을 보세요.

파이썬의 유니코드 지원

이제 유니코드의 기초를 배웠으므로 파이썬의 유니코드 기능을 살펴볼 수 있습니다.

문자열 형

파이썬 3.0부터는 언어의 str 형은 유니코드 문자를 포함하고, 이는 어떤 문자열이든 "unicode rocks!", 'unicode rocks!' 또는 삼중 따옴표로 묶인 문자열 문법을 사용한다면 유니코드로 저장됨을 뜻합니다.

파이썬 소스 코드의 기본 인코딩은 UTF-8이므로 문자열 리터럴에 유니코드 문자를 쉽게 포함할 수 있습니다:

try:
    with open('/tmp/input.txt', 'r') as f:
        ...
except OSError:
    # 'File not found' error message.
    print("Fichier non trouvé")

사이드 노트: 파이썬 3은 유니코드 문자를 식별자에서도 지원합니다:

répertoire = "/tmp/records.log"
with open(répertoire, "w") as f:
    f.write("test\n")

편집기에서 특정 문자를 입력 할수 없거나 어떤 이유에서 ASCII만으로 소스 코드를 작성하고자 한다면, 문자열 리터럴에 이스케이프 시퀀스를 사용할 수 있습니다. (시스템에 따라 다르지만, u 이스케이프 대신에 진짜 대문자 델타 글리프가 나타날 수 있습니다.)

>>> "\N{GREEK CAPITAL LETTER DELTA}"  # Using the character name
'\u0394'
>>> "\u0394"                          # Using a 16-bit hex value
'\u0394'
>>> "\U00000394"                      # Using a 32-bit hex value
'\u0394'

추가로, 문자열을 bytes의 decode() 메서드를 사용하여 만들 수 있습니다. 이 메서드는 UTF-8과 같은 encoding 인자와 선택적으로 erros 인자를 받습니다.

errors 인자는 인코딩의 규칙에 따라 입력 문자열을 변환할 수 없는 경우의 응답을 지정합니다. 이 인자의 유효한 값은 'strict' (UnicodeDecodeError 예외 발생), 'replace' (U+FFFD, REPLACEMENT CHARACTER 사용), 'ignore' (유니코드 결과에서 문자를 그냥 생략), 또는 'backslashreplace' (\xNN 이스케이프 시퀀스를 삽입)입니다. 다음 에제는 그 차이점을 보여줍니다:

>>> b'\x80abc'.decode("utf-8", "strict")
Traceback (most recent call last):
    ...
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 0:
  invalid start byte
>>> b'\x80abc'.decode("utf-8", "replace")
'\ufffdabc'
>>> b'\x80abc'.decode("utf-8", "backslashreplace")
'\\x80abc'
>>> b'\x80abc'.decode("utf-8", "ignore")
'abc'

인코딩은 인코딩의 이름을 포함하는 문자열로 지정됩니다. 파이썬에는 대략 100개의 서로 다른 인코딩이 있습니다. 리스트는 표준 인코딩에서 파이썬 라이브러리 레퍼런스를 보세요. 어떤 인코딩은 다양한 이름을 갖습니다; 예를 들어, 'latin-1', 'iso_8859_1' 그리고 '8859’ 는 전부 같은 인코딩의 동의어입니다.

한 문자 유니코드 문자열은 정수를 받고 해당 코드 포인트를 포함하는 길이 1인 유니코드 문자열을 반환하는 chr() 내장 함수로도 만들 수 있습니다. 반대 작업은 한 문자 유니코드 문자열을 받고 코드 포인트 값을 반환하는 ord() 내장 함수입니다:

>>> chr(57344)
'\ue000'
>>> ord('\ue000')
57344

바이트열로 변환

bytes.decode()의 반대 메서드는 요청된 encoding으로 인코딩 된 유니코드 문자열의 bytes를 반환하는 str.encode()입니다.

errors 매개변수는 decode() 메서드의 매개변수와 같지만 가능한 핸들러를 조금 더 제공합니다. 'strict', 'ignore', 'replace' (이 경우 인코딩할 수 없는 문자 대신에 물음표를 삽입)뿐만 아니라 'xmlcharrefreplace' (XML 문자 참조 삽입), backslashreplace (\uNNNN 이스케이프 시퀀스 삽입) 그리고 namereplace (\N{...} 이스케이프 시퀀스 삽입)도 있습니다.

아래 예제에서 서로 다른 결과를 보여줍니다:

>>> u = chr(40960) + 'abcd' + chr(1972)
>>> u.encode('utf-8')
b'\xea\x80\x80abcd\xde\xb4'
>>> u.encode('ascii')
Traceback (most recent call last):
    ...
UnicodeEncodeError: 'ascii' codec can't encode character '\ua000' in
  position 0: ordinal not in range(128)
>>> u.encode('ascii', 'ignore')
b'abcd'
>>> u.encode('ascii', 'replace')
b'?abcd?'
>>> u.encode('ascii', 'xmlcharrefreplace')
b'&#40960;abcd&#1972;'
>>> u.encode('ascii', 'backslashreplace')
b'\\ua000abcd\\u07b4'
>>> u.encode('ascii', 'namereplace')
b'\\N{YI SYLLABLE IT}abcd\\u07b4'

사용 가능한 인코딩을 등록하고 접근할 수 있도록 하는 저수준 루틴은 codecs 모듈에서 찾을 수 있습니다. 새로운 인코딩을 구현하는 것도 codecs 모듈의 이해가 필요합니다. 하지만 이 모듈에 의해서 반환되는 인코딩과 디코딩 함수는 대체로 편안한 것보다는 저수준이며, 새로운 인코딩을 작성하는 것은 전문적인 작업이므로 HOWTO에서 이 모듈을 다루지는 않겠습니다.

파이썬 소스 코드에서 유니코드 리터럴

파이썬 소스 코드에서 특정한 유니코드 코드 포인트는 \u 이스케이프 시퀀스로 쓸 수 있으며, 코드 포인트를 의미하는 네 개의 16진수가 뒤따릅니다. \U 이스케이프 시퀀스와 비슷하지만 네 개가 아닌 여덟 개의 숫자여야 합니다:

>>> s = "a\xac\u1234\u20ac\U00008000"
... #     ^^^^ two-digit hex escape
... #         ^^^^^^ four-digit Unicode escape
... #                     ^^^^^^^^^^ eight-digit Unicode escape
>>> [ord(c) for c in s]
[97, 172, 4660, 8364, 32768]

127보다 큰 코드 포인트에 대해 이스케이프 시퀀스를 사용하는 것은 양이 적을 때 괜찮지만, 프랑스어나 다른 악센트를 사용하는 언어로 작성된 프로그램 메시지 같이 악센트가 있는 문자를 사용할 경우 성가십니다. chr() 내장 함수를 이용하여 문자열을 조립할 수는 있지만 더 짜증납니다.

사용하는 언어의 자연스러운 인코딩으로 리터럴을 쓸 수 있어야 이상적입니다. 그래야 악센트가 있는 문자를 자연스럽게 표시하는 사용자가 가장 좋아하는 편집기로 파이썬 소스 코드를 편집할 수 있고, 실행시점에 올바른 문자를 가질 수 있습니다.

파이썬은 소스 코드를 UTF-8로 작성하는 것을 기본으로 지원하지만, 원하는 인코딩을 선언한다면 거의 모든 인코딩을 쓸 수 있습니다. 이는 소스 파일의 첫 번째 또는 두 번째 줄에 특별한 주석을 포함해 작동합니다:

#!/usr/bin/env python
# -*- coding: latin-1 -*-

u = 'abcdé'
print(ord(u[-1]))

이 문법은 파일에 지역적인 변수를 명시하는데 사용되는 이맥스 표기법에서 영감을 받았습니다. 이맥스는 수많은 서로 다른 변수를 지원하지만 파이썬은 오직 ‘coding’만을 지원합니다. -*- 기호는 이맥스에게 주석이 특별함을 나타냅니다; 파이썬에게 아무 의미도 없지만 그저 관례를 따르는 것뿐입니다. 파이썬은 주석에서 coding: name이나 coding=name을 찾습니다.

이러한 주석을 포함하지 않는다면, 이미 언급한 것처럼 기본 인코딩으로 UTF-8이 사용됩니다. PEP 263 [https://peps.python.org/pep-0263/]에서 정보를 더 보시기 바랍니다.

유니코드 속성

유니코드 사양은 코드 포인트에 대한 정보 데이터베이스를 포함합니다. 각각 정의한 코드 포인트에 대해서, 정보는 문자의 이름, 카테고리, 적용 가능한 숫자 값(로마 숫자와 같은 숫자 개념을 나타내는 문자, 3분의 1이나 5분의 4와 같은 분수를 표현하는 문자 등)을 포함합니다. 양방향 텍스트에서 코드 포인트를 사용하는 방법과 같은 디스플레이 관련 속성도 있습니다.

아래의 프로그램은 몇몇 개의 문자에 대한 정보를 표시하고 특정한 문자의 숫자 값을 출력합니다:

import unicodedata

u = chr(233) + chr(0x0bf2) + chr(3972) + chr(6000) + chr(13231)

for i, c in enumerate(u):
    print(i, '%04x' % ord(c), unicodedata.category(c), end=" ")
    print(unicodedata.name(c))

# Get numeric value of second character
print(unicodedata.numeric(u[1]))

실행했을 때 다음을 출력합니다:

0 00e9 Ll LATIN SMALL LETTER E WITH ACUTE
1 0bf2 No TAMIL NUMBER ONE THOUSAND
2 0f84 Mn TIBETAN MARK HALANTA
3 1770 Lo TAGBANWA LETTER SA
4 33af So SQUARE RAD OVER S SQUARED
1000.0

카테고리 코드는 문자의 유형을 설명하는 약어입니다. 이것들은 “Letter”, “Number”, “Punctuation”, 또는 “Symbol”과 같은 카테고리로 묶여 있고, 이는 하위 카테고리로 나누어 집니다. 위 결과물에서 코드를 가져와 보면, 'Ll'는 ‘Letter, lowercase’, 'No'는 “Number, other”, 'Mn'은 “Mark, nonspacing”, 그리고 'So'는 “Symbol, other”를 뜻합니다. 카테고리 코드 목록에 대해서는 유니코드 문자 데이터베이스 문서의 일반 카테고리값 섹션 [https://www.unicode.org/reports/tr44/#General_Category_Values]을 보세요.

문자열 비교

유니코드는 문자열 비교를 약간 복잡하게 만듭니다, 같은 문자 집합이 다른 코드 포인트 시퀀스로 표시될 수 있기 때문입니다. 예를 들어, ‘ê’와 같은 문자는 단일 코드 포인트 U+00EA로 표시되거나, ‘e’의 코드 포인트 다음에 ‘COMBINING CIRCUMFLEX ACCENT’의 코드 포인트가 오는 U+0065 U+0302로 표시될 수 있습니다. 인쇄될 때 같은 출력을 생성하지만, 하나는 길이 1의 문자열이고 다른 하나는 길이 2입니다.

대소 문자를 구분하지 않는 비교를 위한 한 가지 도구는 문자열을 유니코드 표준에 설명된 알고리즘에 따라 대소 문자를 구분하지 않는 형식으로 변환하는 casefold() 문자열 메서드입니다. 이 알고리즘은 독일어 문자 ‘ß’(코드 포인트 U+00DF)를 소문자 ‘ss’ 쌍이 되도록 하는 것과 같이 문자를 특수하게 처리합니다.

>>> street = 'Gürzenichstraße'
>>> street.casefold()
'gürzenichstrasse'

A second tool is the unicodedata module’s normalize() function that converts strings to one of several normal forms, where letters followed by a combining character are replaced with single characters. normalize() can be used to perform string comparisons that won’t falsely report inequality if two strings use combining characters differently:

import unicodedata

def compare_strs(s1, s2):
    def NFD(s):
        return unicodedata.normalize('NFD', s)

    return NFD(s1) == NFD(s2)

single_char = 'ê'
multiple_chars = '\N{LATIN SMALL LETTER E}\N{COMBINING CIRCUMFLEX ACCENT}'
print('length of first string=', len(single_char))
print('length of second string=', len(multiple_chars))
print(compare_strs(single_char, multiple_chars))

실행했을 때 다음을 출력합니다:

$ python compare-strs.py
length of first string= 1
length of second string= 2
True

normalize() 함수의 첫 번째 인자는 원하는 정규화 형식을 제공하는 문자열입니다. ‘NFC’, ‘NFKC’, ‘NFD’ 및 ‘NFKD’ 중 하나일 수 있습니다.

유니코드 표준은 또한 대소 문자를 구별하지 않고 비교하지 않는 방법을 지정합니다:

import unicodedata

def compare_caseless(s1, s2):
    def NFD(s):
        return unicodedata.normalize('NFD', s)

    return NFD(NFD(s1).casefold()) == NFD(NFD(s2).casefold())

# Example usage
single_char = 'ê'
multiple_chars = '\N{LATIN CAPITAL LETTER E}\N{COMBINING CIRCUMFLEX ACCENT}'

print(compare_caseless(single_char, multiple_chars))

This will print True. (Why is NFD() invoked twice? Because there are a few characters that make casefold() return a non-normalized string, so the result needs to be normalized again. See section 3.13 of the Unicode Standard for a discussion and an example.)

유니코드 정규식

re 모듈이 지원하는 정규식은 바이트열 또는 문자열로 제공됩니다. \d와 \w 같은 특별한 문자 시퀀스 몇몇은 패턴이 바이트열 또는 문자열에 의해 지원되는지 여부에 따라 다른 의미가 있습니다. 예를 들어, 바이트열에서 \d는 [0-9]와 일치하지만, 문자열에서는 'Nd' 카테고리에 속하는 아무 문자와 일치합니다.

이 예제의 문자열은 태국과 아라비아 숫자로 쓰인 숫자 57을 갖고 있습니다:

import re
p = re.compile(r'\d+')

s = "Over \u0e55\u0e57 57 flavours"
m = p.search(s)
print(repr(m.group()))

실행했을 때, \d+은 태국 숫자와 일치하고 출력합니다. re.ASCII 플래그를 compile()에 제공했을 경우, \d+는 부분 문자열 “57”을 대신 일치시킵니다.

비슷하게, \w는 매우 다양한 유니코드와 일치하지만, 바이트열이거나 re.ASCII가 제공되면 오직 [a-zA-Z0-9_]과 일치하고, \s는 유니코드 공백 문자나 [ \t\n\r\f\v]와 일치합니다.

참조

파이썬 유니코드 지원에 대한 몇 개의 좋은 대안 토론은 다음과 같습니다:

Processing Text Files in Python 3 [https://python-notes.curiousefficiency.org/en/latest/python3/text_file_processing.html], by Nick Coghlan.

Ned Batchelder가 PyCon 2012에서 발표한 실용 유니코드 [https://nedbatchelder.com/text/unipain.html].

str 타입은 파이썬 라이브러리 레퍼런스 텍스트 시퀀스 형 — str에 설명되어 있습니다.

unicodedata 모듈에 대한 문서입니다.

codecs 모듈에 대한 문서입니다.

Marc-André Lemburg는 EuroPython 2002에서 발표한 “파이썬과 유니코드”라는 제목의 프레젠테이션 (PDF 슬라이드) [https://downloads.egenix.com/python/Unicode-EPC2002-Talk.pdf]을 주었습니다. 이 슬라이드는 파이썬 2의 유니코드 기능(유니코드 문자열 타입을 unicode라 부르고 리터럴 u로 시작하는) 디자인에 대한 훌륭한 개요서입니다.

유니코드 데이터 읽고 쓰기

유니코드 데이터로 동작하는 코드를 작성했다면, 다음은 입출력이 문제입니다. 프로그램에 유니코드 문자열을 어떻게 집어넣을 것인가, 그리고 유니코드를 어떻게 저장 또는 전송에 적합한 형식으로 유니코드를 전환할 것인가?

입력 소스 및 출력 대상에 따라 아무것도 할 필요 없을 수도 있습니다; 응용 프로그램에서 사용되는 라이브러리가 유니코드를 기본 지원하는지 확인해야 됩니다. 예를 들어, XML 파서는 종종 유니코드 데이터를 반환합니다. 많은 관계형 데이터베이스 역시 유니코드 값 칼럼을 지원하고, SQL 질의로부터 유니코드 값을 반환받을 수 있습니다.

유니코드 데이터는 디스크에 쓰이거나 소켓에 전달되기 전에 보통 특정 인코딩으로 변경됩니다. 다음의 모든 작업을 직접 할 수 있습니다: 파일 열기, 8-bit 바이트열 객체 읽기, 그리고 bytes.decode(encoding)로 바이트열 전환하기. 하지만 이러한 수동 접근은 권장하지 않습니다.

한 가지 문제는 인코딩의 멀티 바이트 특성입니다; 하나의 유니코드 문자는 여러 바이트로 표현됩니다. 임의의 크기의 청크로 파일을 읽으려면 (1024 또는 4096바이트라 할 때), 단일 유니코드 문자를 인코딩하는 바이트 일부만 청크 끝에 읽는 경우를 잡기 위해 에러 처리 코드를 작성해야 합니다. 한 가지 해결책은 파일 전체를 메모리에 읽고 디코딩을 수행하는 것이지만, 극도로 큰 파일로 작업하는 것을 방해합니다; 2기가바이트 파일을 읽어야만 한다면, 2기가바이트 메모리가 필요합니다. (인코딩된 문자열과 유니코드 버전을 잠깐 메모리에 가지고 있어야 하므로 실제로는 더 필요합니다.)

부분 코딩 시퀀스의 경우를 잡기 위해 저수준 디코딩 인터페이스를 사용하는 것이 해결방법입니다. 이를 구현하는 작업은 이미 수행되었습니다: 내장 open() 함수는 파일 내용물이 지정된 인코딩이라고 가정하고, read() 또는 write()와 같은 메서드에서 유니코드 매개변수를 받아들이는 파일 객체를 반환할 수 있습니다. 이는 str.encode()와 bytes.decode()에서처럼 해석되는 open()의 encoding과 errors 매개변수를 통해 작동합니다.

그러므로 파일에서 유니코드를 읽는 것은 간단합니다:

with open('unicode.txt', encoding='utf-8') as f:
    for line in f:
        print(repr(line))

업데이트 모드로 파일을 열어 읽기 또는 쓰기를 할 수도 있습니다:

with open('test', encoding='utf-8', mode='w+') as f:
    f.write('\u4500 blah blah blah\n')
    f.seek(0)
    print(repr(f.readline()[:1]))

유니코드 문자 U+FEFF는 바이트 순서 표시(BOM)로 사용되고, 파일의 바이트 순서를 자동감지하기 위해 파일의 맨 처음 문자로 쓰이기도 합니다. UTF-16과 같은 일부 인코딩에서는 파일 시작 부분에 BOM이 있어야합니다; 이러한 인코딩이 쓰일 때, BOM이 자동으로 첫번째 문자로 작성되고 파일을 읽을 때 조용히 없어집니다. 리틀 엔디안과 빅 엔디안을 위해 특정 바이트 순서를 지정하고 BOM을 생략하지 않는 ‘utf-16-le’와 ‘utf-16-be’ 같은 인코딩의 변종들이 있습니다.

일부 영역에서는 UTF-8로 인코딩된 파일의 시작 부분에 “BOM”을 사용하는 것이 관례이기도 합니다; UTF-8은 바이트 순서에 의존하지 않으므로 이 이름은 오해의 소지가 있습니다. 이 표시는 이 파일이 UTF-8로 인코딩했음을 단순히 알립니다. 그런 파일을 읽으려면 자동으로 이 표시를 건너뛰기 위해 ‘utf-8-sig’ 코덱을 사용하세요.

유니코드 파일 이름

Most of the operating systems in common use today support filenames that contain arbitrary Unicode characters. Usually this is implemented by converting the Unicode string into some encoding that varies depending on the system. Today Python is converging on using UTF-8: Python on MacOS has used UTF-8 for several versions, and Python 3.6 switched to using UTF-8 on Windows as well. On Unix systems, there will only be a filesystem encoding. if you’ve set the LANG or LC_CTYPE environment variables; if you haven’t, the default encoding is again UTF-8.

인코딩을 수동으로 하고 싶을 때를 대비하여 sys.getfilesystemencoding() 함수는 현재 사용하고 있는 시스템의 인코딩을 반환하지만, 귀찮게 그럴 이유는 없습니다. 읽기 또는 쓰기를 위해 파일을 열 때, 보통 파일 이름으로 유니코드 문자열을 제공하기만 하면 되고, 자동으로 올바른 인코딩으로 변환됩니다:

filename = 'filename\u4500abc'
with open(filename, 'w') as f:
    f.write('blah\n')

os 모듈 안의 os.stat()과 같은 함수 역시 유니코드 파일 이름을 수용합니다.

The os.listdir() function returns filenames, which raises an issue: should it return the Unicode version of filenames, or should it return bytes containing the encoded versions? os.listdir() can do both, depending on whether you provided the directory path as bytes or a Unicode string. If you pass a Unicode string as the path, filenames will be decoded using the filesystem’s encoding and a list of Unicode strings will be returned, while passing a byte path will return the filenames as bytes. For example, assuming the default filesystem encoding is UTF-8, running the following program:

fn = 'filename\u4500abc'
f = open(fn, 'w')
f.close()

import os
print(os.listdir(b'.'))
print(os.listdir('.'))

아래의 출력을 만들 것입니다:

$ python listdir-test.py
[b'filename\xe4\x94\x80abc', ...]
['filename\u4500abc', ...]

첫번째 리스트는 UTF-8로 인코딩된 파일 이름을 갖고, 두 번째 리스트는 유니코드 버전을 갖습니다.

대부분의 경우, 이러한 API로 유니코드만 사용할 수 있음에 유의하십시오. 바이트열 API는 디코딩할 수 없는 파일 이름이 존재하는 시스템에서만 사용해야 합니다; 지금은 유닉스 시스템에 불과합니다.

유니코드 인식 프로그램 작성 팁

이 섹션은 유니코드를 다루는 소프트웨어를 작성할 때의 몇 가지 제안을 제공합니다.

가장 중요한 팁은:

소프트웨어는 가능한 한 빨리 입력 데이터를 디코딩하고 마지막에만 출력을 인코딩하여 내부적으로는 유니코드 문자열에서만 작동하는 것이 좋습니다.

유니코드와 바이트 문자열을 수용하는 처리 함수를 작성하려고 시도한다면, 두 가지 다른 종류의 문자열을 결합할 때마다 프로그램이 버그에 취약하다는 것을 알 수 있습니다. 자동 인코딩이나 디코딩은 없습니다: str + bytes을 수행한다면 TypeError가 발생합니다.

웹 브라우저나 다른 신뢰할 수 없는 소스로부터 온 데이터를 사용할 때, 일반적인 기법은 생성된 명령행에서 문자열을 사용하거나 데이터베이스에 저장하기 전에 문자열에서 잘못된 문자를 검사하는 것입니다. 이렇게 하고 있다면, 인코딩된 바이트열 데이터가 아닌 디코딩 된 문자열을 검사하도록 조심하기 바랍니다; 어떤 인코딩은 일대일 대응되지 않거나 ASCII와 완전히 호환되지 않는 흥미로운 속성을 가지고 있습니다. 입력 데이터가 인코딩을 지정하는 경우 특히 그러한데, 공격자가 인코딩한 바이트 스트림 안에 악의적인 텍스트를 숨기는 방법을 택할 수 있기 때문입니다.

파일 인코딩끼리 변환

StreamRecoder 클래스는 인코딩 #1으로 데이터를 반환하는 스트림을 받아서 인코딩 #2로 데이터를 반환하는 스트림처럼 동작하여 인코딩 간에 투명하게 변환할 수 있습니다.

예를 들어, Latin-1을 사용하는 f 입력 파일을 가지고 있다면, 이를 UTF-8로 인코딩한 바이트열을 반환하기 위해 StreamRecoder로 감쌀 수 있습니다:

new_f = codecs.StreamRecoder(f,
    # en/decoder: used by read() to encode its results and
    # by write() to decode its input.
    codecs.getencoder('utf-8'), codecs.getdecoder('utf-8'),

    # reader/writer: used to read and write to the stream.
    codecs.getreader('latin-1'), codecs.getwriter('latin-1') )

알 수 없는 인코딩의 파일

파일을 변경해야 하지만 파일의 인코딩을 모를 때 할 수 있는 일은 무엇일까요? 인코딩이 ASCII 호환이라는 것을 알고 있고 ASCII 일부분을 검토 또는 수정만 하고자 한다면, surrogateescape 에러 핸들러와 함께 파일을 열 수 있습니다:

with open(fname, 'r', encoding="ascii", errors="surrogateescape") as f:
    data = f.read()

# make changes to the string 'data'

with open(fname + '.new', 'w',
          encoding="ascii", errors="surrogateescape") as f:
    f.write(data)

surrogateescape 에러 핸들러는 비 ASCII 바이트들을 U+DC80부터 U+DCFF까지의 특수한 범위에 있는 코드 포인트로 디코딩합니다. 이러한 코드 포인트는 surrogateescape 에러 핸들러가 데이터를 인코딩하고 다시 쓰는 경우에 사용될 때 같은 바이트열로 다시 되돌려집니다.

참조

One section of Mastering Python 3 Input/Output [https://pyvideo.org/video/289/pycon-2010--mastering-python-3-i-o], a PyCon 2010 talk by David Beazley, discusses text processing and binary data handling.

Marc-André Lemburg의 프레젠테이션 PDF 슬라이드 “파이썬에서 유니코드 인식 프로그램 작성” [https://downloads.egenix.com/python/LSM2005-Developing-Unicode-aware-applications-in-Python.pdf]은 문자 인코딩에 관한 질문은 물론 응용 프로그램을 국제화하고 지역화하는 방법에 관해 설명합니다. 이 슬라이드는 파이썬 2.x만을 다룹니다.

The Guts of Unicode in Python [https://pyvideo.org/video/1768/the-guts-of-unicode-in-python] is a PyCon 2013 talk by Benjamin Peterson that discusses the internal Unicode representation in Python 3.3.

감사 인사

이 문서의 초안은 Andrew Kuchling이 썼습니다. 이후 Alexander Belopolsky, Georg Brandl, Andrew Kuchling, 그리고 Ezio Melotti에 의해 개정되었습니다.

이 문서에 오류를 알려주거나 제안을 해주신 아래의 사람들에게 감사를 전합니다: Éric Araujo, Nicholas Bastin, Nick Coghlan, Marius Gedminas, Kent Johnson, Ken Krugler, Marc-André Lemburg, Martin von Löwis, Terry J. Reedy, Serhiy Storchaka, Eryk Sun, Chad Whitacre, Graham Wideman.

urllib 패키지를 사용하여 인터넷 리소스를 가져오는 방법

저자:

Michael Foord [https://agileabstractions.com/]

소개

Related Articles

파이썬으로 웹 리소스를 가져오는 방법에 대한 다음 기사도 유용합니다:

Basic Authentication [https://web.archive.org/web/20201215133350/http://www.voidspace.org.uk/python/articles/authentication.shtml]

파이썬 예제가 있는 기본 인증(Basic Authentication)에 대한 자습서.

urllib.request는 URL(Uniform Resource Locator)을 가져오기 위한 파이썬 모듈입니다. urlopen 함수의 형태로, 매우 간단한 인터페이스를 제공합니다. 다양한 프로토콜을 사용하여 URL을 가져올 수 있습니다. 또한 기본 인증(basic authentication), 쿠키, 프락시 등과 같은 일반적인 상황을 처리하기 위한 약간 더 복잡한 인터페이스도 제공합니다. 이들은 처리기와 오프너라는 객체에 의해 제공됩니다.

urllib.request는 관련 네트워크 프로토콜(예를 들어 FTP, HTTP)을 사용하여 많은 “URL 스킴(scheme)” (URL에서 ":" 앞의 문자열로 식별됩니다 - 예를 들어 "ftp"는 "ftp://python.org/"의 URL 스킴입니다)에 대해 URL을 가져오는 것을 지원합니다. 이 자습서는 가장 흔한 경우인 HTTP에 초점을 맞춥니다.

간단한 상황에서 urlopen은 사용하기가 매우 쉽습니다. 그러나 HTTP URL을 열 때 에러나 사소하지 않은 사례를 만나자마자, HTTP(HyperText Transfer Protocol)에 대한 이해가 필요합니다. HTTP에 대한 가장 포괄적이고 권위 있는 레퍼런스는 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]입니다. 이것은 기술 문서이며 읽기 쉽지 않습니다. 이 HOWTO에서는 urllib를 사용하는 방법을 설명하고, HTTP에 대해 충분히 자세하게 설명합니다. urllib.request 문서를 대체하려는 것이 아니라, 보조하려는 것입니다.

URL을 가져오기

urllib.request를 사용하는 가장 간단한 방법은 다음과 같습니다:

import urllib.request
with urllib.request.urlopen('http://python.org/') as response:
   html = response.read()

URL을 통해 리소스를 가져와서 임시 위치에 저장하려면, shutil.copyfileobj()와 tempfile.NamedTemporaryFile() 함수를 통해 수행할 수 있습니다:

import shutil
import tempfile
import urllib.request

with urllib.request.urlopen('http://python.org/') as response:
    with tempfile.NamedTemporaryFile(delete=False) as tmp_file:
        shutil.copyfileobj(response, tmp_file)

with open(tmp_file.name) as html:
    pass

urllib의 많은 용도는 이렇게 간단합니다 (‘http:’ URL 대신 ‘ftp:’, ‘file:’ 등으로 시작하는 URL을 사용할 수 있음에 유의하십시오). 그러나, 이 자습서의 목적은 HTTP에 집중하여 더 복잡한 경우를 설명하는 것입니다.

HTTP는 요청과 응답을 기반으로 합니다 - 클라이언트는 요청하고 서버는 응답을 보냅니다. urllib.request는 HTTP 요청을 나타내는 Request 객체로 이것을 반영합니다. 가장 간단한 형식에서 가져오려는 URL을 지정하는 Request 객체를 만듭니다. 이 Request 객체로 urlopen을 호출하면 요청된 URL에 대한 응답 객체를 반환합니다. 이 응답은 파일류 객체입니다, 응답에서 예를 들어 .read()를 호출할 수 있다는 뜻입니다:

import urllib.request

req = urllib.request.Request('http://python.org/')
with urllib.request.urlopen(req) as response:
   the_page = response.read()

urllib.request는 모든 URL 스킴을 처리하기 위해 같은 Request 인터페이스를 사용합니다. 예를 들어, 다음과 같이 FTP 요청을 할 수 있습니다:

req = urllib.request.Request('ftp://example.com/')

HTTP의 경우, Request 객체로 수행할 수 있는 추가 작업이 두 가지 있습니다: 첫째, 서버로 보낼 데이터를 전달할 수 있습니다. 둘째, 데이터나 요청 자체에 관한 추가 정보(“메타 데이터”)를 서버에 전달할 수 있습니다 - 이 정보는 HTTP “헤더”로 전송됩니다. 이들을 차례로 살펴봅시다.

데이터

URL로 데이터를 보내려고 할 때도 있습니다 (종종 URL은 CGI (Common Gateway Interface) 스크립트나 다른 웹 응용 프로그램을 가리킵니다). HTTP에서, 이것은 종종 POST 요청이라고 알려진 것을 사용하여 수행됩니다. 이것은 종종 웹에서 채워 넣은 HTML 폼(form)을 제출할 때 브라우저가 수행하는 것입니다. 모든 POST가 폼에서 비롯될 필요는 없습니다: POST를 사용하여 임의의 데이터를 여러분 자신의 응용 프로그램으로 전송할 수 있습니다. 일반적인 HTML 폼의 경우, 데이터를 표준 방식으로 인코딩할 필요가 있고, 그런 다음 data 인자로 Request 객체에 전달합니다. 인코딩은 urllib.parse 라이브러리의 함수를 사용하여 수행됩니다.

import urllib.parse
import urllib.request

url = 'http://www.someserver.com/cgi-bin/register.cgi'
values = {'name' : 'Michael Foord',
          'location' : 'Northampton',
          'language' : 'Python' }

data = urllib.parse.urlencode(values)
data = data.encode('ascii') # data should be bytes
req = urllib.request.Request(url, data)
with urllib.request.urlopen(req) as response:
   the_page = response.read()

다른 인코딩이 필요한 경우도 있음에 유의하십시오 (예를 들어 HTML 폼에서 파일을 업로드하는 경우 자세한 내용은 HTML Specification, Form Submission [https://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13]을 참조하십시오).

data 인자를 전달하지 않으면, urllib는 GET 요청을 사용합니다. GET과 POST 요청이 다른 한 가지는 POST 요청에 종종 “부작용”이 있다는 것입니다: 어떤 방식으로든 시스템의 상태를 변경합니다 (예를 들어 캔에 담긴 스팸이 여러분의 문 앞에 배달되도록 주문을 넣습니다). HTTP 표준이 POST는 항상 부작용을 일으키려는 것이고, GET은 절대 부작용을 일으키지 않는다고 분명히 하고 있지만, GET 요청이 부작용을 일으키거나 POST 요청에 부작용이 없는 것을 막을 수는 없습니다. URL 자체에 인코딩하여 HTTP GET 요청에 데이터를 전달할 수도 있습니다.

다음과 같이 수행됩니다:

>>> import urllib.request
>>> import urllib.parse
>>> data = {}
>>> data['name'] = 'Somebody Here'
>>> data['location'] = 'Northampton'
>>> data['language'] = 'Python'
>>> url_values = urllib.parse.urlencode(data)
>>> print(url_values)  # The order may differ from below.
name=Somebody+Here&language=Python&location=Northampton
>>> url = 'http://www.example.com/example.cgi'
>>> full_url = url + '?' + url_values
>>> data = urllib.request.urlopen(full_url)

전체 URL은 URL에 ?를 추가한 다음 인코딩된 값을 추가하여 만들어짐에 유의하십시오.

헤더

여기서는 HTTP 요청에 헤더를 추가하는 방법을 설명하기 위해 한 가지 특정 HTTP 헤더에 관해 설명합니다.

일부 웹 사이트는 [1] 프로그램이 브라우징하는 것을 싫어하거나, 브라우저에 따라 다른 버전을 보냅니다 [2]. 기본적으로, urllib는 자신을 Python-urllib/x.y(여기서 x 와 y는 파이썬 배포의 주 버전과 부 버전 번호입니다, 예를 들어 Python-urllib/2.5)로 식별하는데, 이는 사이트를 혼동시키거나, 단지 작동하지 않을 수 있습니다. 브라우저가 자신을 식별하는 방식은 User-Agent 헤더를 [3] 통하는 것입니다. Request 객체를 만들 때 헤더가 담긴 딕셔너리를 전달할 수 있습니다. 다음 예제는 위와 같은 요청을 하지만, 자신을 Internet Explorer의 한 버전으로 식별합니다 [4].

import urllib.parse
import urllib.request

url = 'http://www.someserver.com/cgi-bin/register.cgi'
user_agent = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64)'
values = {'name': 'Michael Foord',
          'location': 'Northampton',
          'language': 'Python' }
headers = {'User-Agent': user_agent}

data = urllib.parse.urlencode(values)
data = data.encode('ascii')
req = urllib.request.Request(url, data, headers)
with urllib.request.urlopen(req) as response:
   the_page = response.read()

응답에는 두 가지 유용한 메서드도 있습니다. 문제가 발생했을 때 어떤 일이 발생했는지 살펴본 후에 나오는 info와 geturl 섹션을 참조하십시오.

예외 처리

urlopen raises URLError when it cannot handle a response (though as usual with Python APIs, built-in exceptions such as ValueError, TypeError etc. may also be raised).

HTTPError is the subclass of URLError raised in the specific case of HTTP URLs.

예외 클래스는 urllib.error 모듈이 내보냅니다.

URLError

종종, 네트워크 연결이 없거나 (지정된 서버로의 경로가 없거나), 지정된 서버가 없기 때문에 URLError가 발생합니다. 이 경우, 발생한 예외에는 ‘reason’ 어트리뷰트가 있으며, 이는 에러 코드와 텍스트 에러 메시지를 포함하는 튜플입니다.

예를 들어

>>> req = urllib.request.Request('http://www.pretend_server.org')
>>> try: urllib.request.urlopen(req)
... except urllib.error.URLError as e:
...     print(e.reason)
...
(4, 'getaddrinfo failed')

HTTPError

Every HTTP response from the server contains a numeric “status code”. Sometimes the status code indicates that the server is unable to fulfil the request. The default handlers will handle some of these responses for you (for example, if the response is a “redirection” that requests the client fetch the document from a different URL, urllib will handle that for you). For those it can’t handle, urlopen will raise an HTTPError. Typical errors include ‘404’ (page not found), ‘403’ (request forbidden), and ‘401’ (authentication required).

모든 HTTP 에러 코드에 대한 레퍼런스는 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]의 섹션 10을 참조하십시오.

The HTTPError instance raised will have an integer ‘code’ attribute, which corresponds to the error sent by the server.

에러 코드

기본 처리기는 리디렉션(300 범위의 코드)을 처리하고, 100–299 범위의 코드는 성공을 나타내므로, 보통 400–599 범위의 에러 코드만 보게 됩니다.

http.server.BaseHTTPRequestHandler.responses는 RFC 2616 [https://datatracker.ietf.org/doc/html/rfc2616.html]가 사용하는 모든 응답 코드를 표시하는 유용한 응답 코드 딕셔너리입니다. 편의를 위해 딕셔너리를 여기에 재현합니다

# Table mapping response codes to messages; entries have the
# form {code: (shortmessage, longmessage)}.
responses = {
    100: ('Continue', 'Request received, please continue'),
    101: ('Switching Protocols',
          'Switching to new protocol; obey Upgrade header'),

    200: ('OK', 'Request fulfilled, document follows'),
    201: ('Created', 'Document created, URL follows'),
    202: ('Accepted',
          'Request accepted, processing continues off-line'),
    203: ('Non-Authoritative Information', 'Request fulfilled from cache'),
    204: ('No Content', 'Request fulfilled, nothing follows'),
    205: ('Reset Content', 'Clear input form for further input.'),
    206: ('Partial Content', 'Partial content follows.'),

    300: ('Multiple Choices',
          'Object has several resources -- see URI list'),
    301: ('Moved Permanently', 'Object moved permanently -- see URI list'),
    302: ('Found', 'Object moved temporarily -- see URI list'),
    303: ('See Other', 'Object moved -- see Method and URL list'),
    304: ('Not Modified',
          'Document has not changed since given time'),
    305: ('Use Proxy',
          'You must use proxy specified in Location to access this '
          'resource.'),
    307: ('Temporary Redirect',
          'Object moved temporarily -- see URI list'),

    400: ('Bad Request',
          'Bad request syntax or unsupported method'),
    401: ('Unauthorized',
          'No permission -- see authorization schemes'),
    402: ('Payment Required',
          'No payment -- see charging schemes'),
    403: ('Forbidden',
          'Request forbidden -- authorization will not help'),
    404: ('Not Found', 'Nothing matches the given URI'),
    405: ('Method Not Allowed',
          'Specified method is invalid for this server.'),
    406: ('Not Acceptable', 'URI not available in preferred format.'),
    407: ('Proxy Authentication Required', 'You must authenticate with '
          'this proxy before proceeding.'),
    408: ('Request Timeout', 'Request timed out; try again later.'),
    409: ('Conflict', 'Request conflict.'),
    410: ('Gone',
          'URI no longer exists and has been permanently removed.'),
    411: ('Length Required', 'Client must specify Content-Length.'),
    412: ('Precondition Failed', 'Precondition in headers is false.'),
    413: ('Request Entity Too Large', 'Entity is too large.'),
    414: ('Request-URI Too Long', 'URI is too long.'),
    415: ('Unsupported Media Type', 'Entity body in unsupported format.'),
    416: ('Requested Range Not Satisfiable',
          'Cannot satisfy request range.'),
    417: ('Expectation Failed',
          'Expect condition could not be satisfied.'),

    500: ('Internal Server Error', 'Server got itself in trouble'),
    501: ('Not Implemented',
          'Server does not support this operation'),
    502: ('Bad Gateway', 'Invalid responses from another server/proxy.'),
    503: ('Service Unavailable',
          'The server cannot process the request due to a high load'),
    504: ('Gateway Timeout',
          'The gateway server did not receive a timely response'),
    505: ('HTTP Version Not Supported', 'Cannot fulfill request.'),
    }

When an error is raised the server responds by returning an HTTP error code and an error page. You can use the HTTPError instance as a response on the page returned. This means that as well as the code attribute, it also has read, geturl, and info, methods as returned by the urllib.response module:

>>> req = urllib.request.Request('http://www.python.org/fish.html')
>>> try:
...     urllib.request.urlopen(req)
... except urllib.error.HTTPError as e:
...     print(e.code)
...     print(e.read())
...
404
b'<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">\n\n\n<html
  ...
  <title>Page Not Found</title>\n
  ...

마무리

So if you want to be prepared for HTTPError or URLError there are two basic approaches. I prefer the second approach.

1번

from urllib.request import Request, urlopen
from urllib.error import URLError, HTTPError
req = Request(someurl)
try:
    response = urlopen(req)
except HTTPError as e:
    print('The server couldn\'t fulfill the request.')
    print('Error code: ', e.code)
except URLError as e:
    print('We failed to reach a server.')
    print('Reason: ', e.reason)
else:
    # everything is fine

참고

The except HTTPError must come first, otherwise except URLError will also catch an HTTPError.

2번

from urllib.request import Request, urlopen
from urllib.error import URLError
req = Request(someurl)
try:
    response = urlopen(req)
except URLError as e:
    if hasattr(e, 'reason'):
        print('We failed to reach a server.')
        print('Reason: ', e.reason)
    elif hasattr(e, 'code'):
        print('The server couldn\'t fulfill the request.')
        print('Error code: ', e.code)
else:
    # everything is fine

info와 geturl

The response returned by urlopen (or the HTTPError instance) has two useful methods info() and geturl() and is defined in the module urllib.response.

geturl - 가져온 페이지의 실제 URL을 반환합니다. 이는 urlopen(또는 사용된 오프너 객체)이 리디렉션을 수행했을 수 있기 때문에 유용합니다. 가져온 페이지의 URL은 요청한 URL과 같지 않을 수 있습니다.

info - 가져온 페이지를 설명하는 딕셔너리류 객체, 특히 서버가 보낸 헤더. 현재 http.client.HTTPMessage 인스턴스입니다.

Typical headers include ‘Content-length’, ‘Content-type’, and so on. See the Quick Reference to HTTP Headers [https://jkorpela.fi/http.html] for a useful listing of HTTP headers with brief explanations of their meaning and use.

오프너와 처리기

When you fetch a URL you use an opener (an instance of the perhaps confusingly named urllib.request.OpenerDirector). Normally we have been using the default opener - via urlopen - but you can create custom openers. Openers use handlers. All the “heavy lifting” is done by the handlers. Each handler knows how to open URLs for a particular URL scheme (http, ftp, etc.), or how to handle an aspect of URL opening, for example HTTP redirections or HTTP cookies.

특정 처리기가 설치된 상태로 URL을 가져오려면 오프너를 만듭니다, 예를 들면 쿠키를 처리하는 오프너를 얻거나, 리디렉션을 처리하지 않는 오프너를 얻는 것이 있습니다.

오프너를 만들려면, OpenerDirector를 인스턴스화 한 다음, .add_handler(some_handler_instance)를 반복적으로 호출합니다.

또는, 단일 함수 호출로 오프너 객체를 만드는 편의 함수인 build_opener를 사용할 수 있습니다. build_opener는 기본적으로 여러 처리기를 추가하지만, 더 추가하거나 기본 처리기를 재정의하는 빠른 방법을 제공합니다.

여러분이 원할 수도 있는 다른 유형의 처리기는 프락시, 인증 및 다른 흔하지만 약간 특수한 상황을 처리할 수 있습니다.

install_opener를 사용하여 opener 객체를 (전역) 기본 오프너로 만들 수 있습니다. 즉, urlopen을 호출하면 설치한 오프너가 사용됩니다.

오프너 객체에는 urlopen 함수와 같은 방식으로 URL을 가져오기 위해 직접 호출할 수 있는 open 메서드가 있습니다: 편의 이외에, install_opener를 호출할 필요는 없습니다.

기본 인증

To illustrate creating and installing a handler we will use the HTTPBasicAuthHandler. For a more detailed discussion of this subject – including an explanation of how Basic Authentication works - see the Basic Authentication Tutorial [https://web.archive.org/web/20201215133350/http://www.voidspace.org.uk/python/articles/authentication.shtml].

인증이 필요할 때, 서버는 (401 에러 코드와 함께) 인증을 요청하는 헤더를 보냅니다. 이것은 인증 스킴과 ‘영역(realm)’을 지정합니다. 헤더는 이렇게 생겼습니다: WWW-Authenticate: SCHEME realm="REALM".

예를 들어

WWW-Authenticate: Basic realm="cPanel Users"

그러면 클라이언트는 영역에 적절한 이름과 비밀번호를 요청의 헤더로 포함해 요청을 다시 시도해야 합니다. 이것이 ‘기본 인증(basic authentication)’입니다. 이 프로세스를 단순화하기 위해 HTTPBasicAuthHandler 인스턴스와 이 처리기를 사용할 오프너를 만들 수 있습니다.

HTTPBasicAuthHandler는 비밀번호 관리자(password manager)라는 객체를 사용하여 URL과 영역에서 비밀번호(password)와 사용자 이름(username)으로의 매핑을 처리합니다. (서버가 보낸 인증 헤더로부터) 영역이 무엇인지 안다면, HTTPPasswordMgr를 사용할 수 있습니다. 종종 영역이 무엇인지 상관하지 않습니다. 이 경우, HTTPPasswordMgrWithDefaultRealm를 사용하는 것이 편리합니다. 이것은 URL의 기본 사용자 이름과 비밀번호를 지정할 수 있습니다. 특정 영역에 대한 대체 조합을 제공하지 않으면 이것이 제공됩니다. None을 add_password 메서드에 대한 realm 인자로 제공하여 이를 나타냅니다.

최상위 URL은 인증이 필요한 첫 번째 URL입니다. .add_password()에 전달한 URL보다 “더 깊은” URL도 일치합니다.

# create a password manager
password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()

# Add the username and password.
# If we knew the realm, we could use it instead of None.
top_level_url = "http://example.com/foo/"
password_mgr.add_password(None, top_level_url, username, password)

handler = urllib.request.HTTPBasicAuthHandler(password_mgr)

# create "opener" (OpenerDirector instance)
opener = urllib.request.build_opener(handler)

# use the opener to fetch a URL
opener.open(a_url)

# Install the opener.
# Now all calls to urllib.request.urlopen use our opener.
urllib.request.install_opener(opener)

참고

In the above example we only supplied our HTTPBasicAuthHandler to build_opener. By default openers have the handlers for normal situations – ProxyHandler (if a proxy setting such as an http_proxy environment variable is set), UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, DataHandler, HTTPErrorProcessor.

top_level_url은 실제로 (‘http:’ 스킴 구성 요소와 호스트 이름 및 선택적인 포트 번호를 포함하는) 전체 URL, 예를 들어 "http://example.com/" 이거나 “주체(authority)” (즉, 선택적으로 포트 번호를 포함하는 호스트명), 예를 들어 "example.com"이나 "example.com:8080" (후자의 예는 포트 번호를 포함합니다)입니다. 주체가 있다면 “userinfo” 구성 요소를 포함하지 않아야 합니다 - 예를 들어 "joe:password@example.com"은 올바르지 않습니다.

프락시

urllib는 프락시 설정을 자동 감지하여 사용합니다. 이는 프락시 설정이 감지될 때 일반 처리기 체인의 일부가 되는 ProxyHandler를 통해 이루어집니다. 일반적으로 좋은 일이지만, 도움이 되지 않는 경우가 있습니다 [5]. 이를 위한 한 가지 방법은 프락시가 정의되지 않은 자체 ProxyHandler를 설정하는 것입니다. 이것은 Basic Authentication [https://web.archive.org/web/20201215133350/http://www.voidspace.org.uk/python/articles/authentication.shtml] 처리기 설정과 비슷한 단계를 사용하여 수행됩니다:

>>> proxy_support = urllib.request.ProxyHandler({})
>>> opener = urllib.request.build_opener(proxy_support)
>>> urllib.request.install_opener(opener)

참고

현재 urllib.request는 프락시를 통한 https 위치를 가져오는 것을 지원하지 않습니다. 그러나, 조리법에 표시된 대로 urllib.request를 확장하여 활성화할 수 있습니다 [6].

참고

변수 REQUEST_METHOD가 설정되면 HTTP_PROXY는 무시됩니다; getproxies()의 설명서를 참조하십시오.

소켓과 계층

웹에서 리소스를 가져오기 위한 파이썬 지원은 계층화되어 있습니다. urllib는 http.client 라이브러리를 사용하고, 이것은 다시 socket 라이브러리를 사용합니다.

파이썬 2.3부터 시간제한으로 중단되기 전에 소켓이 응답을 기다리는 시간을 지정할 수 있습니다. 웹 페이지를 가져와야 하는 응용 프로그램에서 유용 할 수 있습니다. 기본적으로 소켓 모듈에는 시간제한이 없고 멈출(hang) 수 있습니다. 현재, 소켓 시간제한은 http.client나 urllib.request 수준에서 노출되지 않습니다. 그러나, 다음과 같이 모든 소켓에 대해 기본 시간제한을 전역적으로 설정할 수 있습니다

import socket
import urllib.request

# timeout in seconds
timeout = 10
socket.setdefaulttimeout(timeout)

# this call to urllib.request.urlopen now uses the default timeout
# we have set in the socket module
req = urllib.request.Request('http://www.voidspace.org.uk')
response = urllib.request.urlopen(req)

각주

이 문서는 John Lee가 검토하고 수정했습니다.

[1]

예를 들어 구글.

[2]

브라우저 스니핑(browser sniffing)은 웹 사이트 디자인에 매우 나쁜 습관입니다 - 웹 표준을 사용하여 사이트를 구축하는 것이 훨씬 합리적입니다. 불행히도 많은 사이트가 여전히 브라우저마다 다른 버전을 보냅니다.

[3]

MSIE 6의 사용자 에이전트(user agent)는 ‘Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)’입니다.

[4]

더 많은 HTTP 요청 헤더에 대한 자세한 내용은 Quick Reference to HTTP Headers [https://jkorpela.fi/http.html]를 참조하십시오.

[5]

제 경우에는 직장에서 인터넷에 액세스하려면 프락시를 사용해야 합니다. 이 프락시를 통해 localhost URL을 가져오려고 시도하면 차단됩니다. IE는 프락시를 사용하도록 설정되어 있고, urllib는 이것을 선택합니다. localhost 서버로 스크립트를 테스트하려면, urllib가 프락시를 사용하지 못하게 해야 합니다.

[6]

urllib opener for SSL proxy (CONNECT method): ASPN Cookbook Recipe [https://code.activestate.com/recipes/456195-urrlib2-opener-for-ssl-proxy-connect-method/].

ipaddress 모듈에 대한 소개

저자:

Peter Moody

저자:

Nick Coghlan

개요

이 문서에서는 ipaddress 모듈을 간략하게 소개하고자 합니다. 주로 IP 네트워킹 용어에 익숙하지 않은 사용자를 대상으로 하지만, ipaddress가 IP 네트워크 주소 개념을 나타내는 방식에 대한 개요를 원하는 네트워크 엔지니어에게 유용할 수도 있습니다.

주소/네트워크/인터페이스 객체 만들기

ipaddress는 IP 주소를 검사하고 조작하는 모듈이기 때문에, 가장 먼저 하고 싶어 할 일은 몇몇 객체를 만드는 것입니다. ipaddress를 사용하여 문자열과 정수로 객체를 만들 수 있습니다.

IP 버전에 대한 참고 사항

For readers that aren’t particularly familiar with IP addressing, it’s important to know that the Internet Protocol (IP) is currently in the process of moving from version 4 of the protocol to version 6. This transition is occurring largely because version 4 of the protocol doesn’t provide enough addresses to handle the needs of the whole world, especially given the increasing number of devices with direct connections to the internet.

프로토콜의 두 버전 간의 차이점에 대한 자세한 설명은 이 소개의 범위를 벗어나지만, 독자는 최소한 이 두 버전이 존재한다는 사실을 알고 있어야 하며, 때로는 한 버전이나 다른 버전을 강제로 사용해야 할 필요가 있습니다.

IP 호스트 주소

주소, 종종 “호스트 주소” 라고 하는 것은 IP 주소 지정으로 작업할 때 가장 기본 단위입니다. 주소를 만드는 가장 간단한 방법은 ipaddress.ip_address() 팩토리 함수를 사용하는 것인데, 전달된 값을 기반으로 IPv4나 IPv6 주소 중 어느 것을 만들지 자동으로 결정합니다:

>>> ipaddress.ip_address('192.0.2.1')
IPv4Address('192.0.2.1')
>>> ipaddress.ip_address('2001:DB8::1')
IPv6Address('2001:db8::1')

주소는 정수에서 직접 만들 수도 있습니다. 32비트에 들어맞는 값은 IPv4 주소로 간주합니다:

>>> ipaddress.ip_address(3221225985)
IPv4Address('192.0.2.1')
>>> ipaddress.ip_address(42540766411282592856903984951653826561)
IPv6Address('2001:db8::1')

IPv4나 IPv6 주소를 강제로 사용하려면, 해당 클래스를 직접 호출할 수 있습니다. 이것은 작은 정수를 위한 IPv6 주소 생성을 강제하는 데 특히 유용합니다:

>>> ipaddress.ip_address(1)
IPv4Address('0.0.0.1')
>>> ipaddress.IPv4Address(1)
IPv4Address('0.0.0.1')
>>> ipaddress.IPv6Address(1)
IPv6Address('::1')

네트워크 정의

호스트 주소는 대개 IP 네트워크로 그룹화되므로, ipaddress는 네트워크 정의를 만들고, 검사하고, 조작할 방법을 제공합니다. IP 네트워크 객체는 해당 네트워크의 일부인 호스트 주소의 범위를 정의하는 문자열로 만들어집니다. 이 정보의 가장 간단한 형식은 “네트워크 주소/네트워크 접두사” 쌍입니다. 접두어는 주소가 네트워크 일부인지 판별하기 위해 비교되는 선행 비트 수를 정의하고, 네트워크 주소는 그 비트들의 기대되는 값을 정의합니다.

주소의 경우, 정확한 IP 버전을 자동으로 결정하는 팩토리 함수가 제공됩니다:

>>> ipaddress.ip_network('192.0.2.0/24')
IPv4Network('192.0.2.0/24')
>>> ipaddress.ip_network('2001:db8::0/96')
IPv6Network('2001:db8::/96')

네트워크 객체는 호스트 비트가 설정될 수 없습니다. 이것의 실제 효과는 192.0.2.1/24가 네트워크를 설명하지 않는다는 것입니다. 이러한 정의는 인터페이스 객체라고 불리는데, 그 이유는 주어진 네트워크상의 컴퓨터의 네트워크 인터페이스를 기술하기 위해 네트워크상의 IP(ip-on-a-network) 표기법이 일반적으로 사용되기 때문입니다. 자세한 내용은 다음 절에서 설명합니다.

기본적으로, 호스트 비트가 설정된 네트워크 객체를 만들려고 하면 ValueError가 발생합니다. 추가 비트를 강제로 0으로 변환하도록 요청하려면, 플래그 strict=False를 생성자에 전달할 수 있습니다:

>>> ipaddress.ip_network('192.0.2.1/24')
Traceback (most recent call last):
   ...
ValueError: 192.0.2.1/24 has host bits set
>>> ipaddress.ip_network('192.0.2.1/24', strict=False)
IPv4Network('192.0.2.0/24')

문자열 형식은 유연성이 훨씬 뛰어나지만, 호스트 주소와 마찬가지로 정수로 네트워크를 정의할 수도 있습니다. 이 경우, 네트워크는 정수로 식별되는 단일 주소만 포함하는 것으로 간주하므로, 네트워크 접두사는 전체 네트워크 주소를 포함합니다:

>>> ipaddress.ip_network(3221225984)
IPv4Network('192.0.2.0/32')
>>> ipaddress.ip_network(42540766411282592856903984951653826560)
IPv6Network('2001:db8::/128')

주소와 마찬가지로, 팩토리 함수를 사용하는 대신 클래스 생성자를 직접 호출하여 특정 종류의 네트워크를 만들 수 있습니다.

호스트 인터페이스

위에서 언급했듯이, 특정 네트워크상의 주소를 설명해야 하는 경우, 주소로도 네트워크 클래스로도 충분하지 않습니다. 192.0.2.1/24와 같은 표기법은 네트워크 엔지니어와 방화벽과 라우터 용 도구를 작성하는 사람들이 “네트워크 192.0.2.0/24 상의 호스트 192.0.2.1" 의 줄임말로 많이 사용합니다. 따라서, ipaddress는 주소를 특정 네트워크와 결합하는 혼성 클래스 집합을 제공합니다. 생성을 위한 인터페이스는 주소 부분이 네트워크 주소로 제한되지 않는 것을 제외하고는 네트워크 객체를 정의하는 것과 같습니다.

>>> ipaddress.ip_interface('192.0.2.1/24')
IPv4Interface('192.0.2.1/24')
>>> ipaddress.ip_interface('2001:db8::1/96')
IPv6Interface('2001:db8::1/96')

정수 입력이 받아들여지고 (네트워크처럼), 특정 IP 버전의 사용은 관련 생성자를 직접 호출함으로써 강제될 수 있습니다.

주소/네트워크/인터페이스 객체 검사

여러분은 IPv(4|6)(Address|Network|Interface) 객체를 만드는 데 어려움을 겪었다면, 아마도 이에 대한 정보를 얻고 자 할 것입니다. ipaddress는 이 작업을 쉽고 직관적으로 만들려고 합니다.

IP 버전 추출하기:

>>> addr4 = ipaddress.ip_address('192.0.2.1')
>>> addr6 = ipaddress.ip_address('2001:db8::1')
>>> addr6.version
6
>>> addr4.version
4

인터페이스에서 네트워크 얻기:

>>> host4 = ipaddress.ip_interface('192.0.2.1/24')
>>> host4.network
IPv4Network('192.0.2.0/24')
>>> host6 = ipaddress.ip_interface('2001:db8::1/96')
>>> host6.network
IPv6Network('2001:db8::/96')

네트워크에 있는 개별 주소의 개수 찾기:

>>> net4 = ipaddress.ip_network('192.0.2.0/24')
>>> net4.num_addresses
256
>>> net6 = ipaddress.ip_network('2001:db8::0/96')
>>> net6.num_addresses
4294967296

네트워크에서 “사용 가능한” 주소 이터레이트하기:

>>> net4 = ipaddress.ip_network('192.0.2.0/24')
>>> for x in net4.hosts():
...     print(x)
192.0.2.1
192.0.2.2
192.0.2.3
192.0.2.4
...
192.0.2.252
192.0.2.253
192.0.2.254

넷 마스크(netmask)(즉, 네트워크 접두사에 해당하는 비트들)나 호스트 마스크(hostmask)(넷 마스크에 포함되지 않은 비트들) 얻기:

>>> net4 = ipaddress.ip_network('192.0.2.0/24')
>>> net4.netmask
IPv4Address('255.255.255.0')
>>> net4.hostmask
IPv4Address('0.0.0.255')
>>> net6 = ipaddress.ip_network('2001:db8::0/96')
>>> net6.netmask
IPv6Address('ffff:ffff:ffff:ffff:ffff:ffff::')
>>> net6.hostmask
IPv6Address('::ffff:ffff')

주소를 펼치거나 압축하기:

>>> addr6.exploded
'2001:0db8:0000:0000:0000:0000:0000:0001'
>>> addr6.compressed
'2001:db8::1'
>>> net6.exploded
'2001:0db8:0000:0000:0000:0000:0000:0000/96'
>>> net6.compressed
'2001:db8::/96'

IPv4는 펼치기와 압축을 지원하지 않지만, 연관된 객체는 여전히 관련 프로퍼티를 제공하므로 버전 중립적인 코드가 IPv4 주소를 올바르게 처리하면서도 IPv6 주소에 대해 가장 간결하거나 가장 자세한 형식을 쉽게 사용할 수 있습니다.

주소 리스트로서의 네트워크

네트워크를 리스트로 취급하는 것이 때로 유용합니다. 즉, 다음과 같이 인덱싱할 수 있습니다:

>>> net4[1]
IPv4Address('192.0.2.1')
>>> net4[-1]
IPv4Address('192.0.2.255')
>>> net6[1]
IPv6Address('2001:db8::1')
>>> net6[-1]
IPv6Address('2001:db8::ffff:ffff')

이것은 또한 네트워크 객체가 다음과 같은 리스트 멤버십 테스트 문법을 사용하는 데 적합하다는 것을 의미합니다:

if address in network:
    # do something

포함 테스트는 네트워크 접두어를 기반으로 효율적으로 수행됩니다:

>>> addr4 = ipaddress.ip_address('192.0.2.1')
>>> addr4 in ipaddress.ip_network('192.0.2.0/24')
True
>>> addr4 in ipaddress.ip_network('192.0.3.0/24')
False

비교

ipaddress는 의미가 있는 곳에서 객체를 비교하는 간단하고 직관적인 방법을 제공합니다:

>>> ipaddress.ip_address('192.0.2.1') < ipaddress.ip_address('192.0.2.2')
True

다른 버전이나 다른 형의 객체를 비교하려고 하면 TypeError 예외가 발생합니다.

다른 모듈과 함께 IP 주소 사용하기

IP 주소를 사용하는 다른 모듈(가령 socket)은 일반적으로 이 모듈의 객체를 직접 받아들이지 않습니다. 대신, 다른 모듈이 받아들일 수 있는 정수나 문자열로 강제 변환되어야 합니다:

>>> addr4 = ipaddress.ip_address('192.0.2.1')
>>> str(addr4)
'192.0.2.1'
>>> int(addr4)
3221225985

인스턴스 생성 실패 시 세부 사항 가져오기

버전에 구애받지 않는 팩토리 함수를 사용하여 주소/네트워크/인터페이스 객체를 만들 때, 단순히 전달된 값이 해당 형의 객체로 인식되지 않는다는 일반 에러 메시지와 함께 에러가 ValueError로 보고됩니다. 구체적인 에러가 없는 이유는 거부된 이유에 대한 자세한 정보를 제공하기 위해서는 값이 IPv4나 IPv6 중 어는 것으로 가정되는지를 알아야 하기 때문입니다.

이 추가 세부 정보를 액세스하는 것이 유용한 사용 사례를 지원하기 위해, 개별 클래스 생성자는 실제로 ValueError 서브 클래스 ipaddress.AddressValueError와 ipaddress.NetmaskValueError를 발생시켜 정의의 어느 부분에서 구문 분석하는 데 실패했는지 정확히 가리킵니다.

에러 메시지는 클래스 생성자를 직접 사용할 때 훨씬 자세해집니다. 예를 들어:

>>> ipaddress.ip_address("192.168.0.256")
Traceback (most recent call last):
  ...
ValueError: '192.168.0.256' does not appear to be an IPv4 or IPv6 address
>>> ipaddress.IPv4Address("192.168.0.256")
Traceback (most recent call last):
  ...
ipaddress.AddressValueError: Octet 256 (> 255) not permitted in '192.168.0.256'

>>> ipaddress.ip_network("192.168.0.1/64")
Traceback (most recent call last):
  ...
ValueError: '192.168.0.1/64' does not appear to be an IPv4 or IPv6 network
>>> ipaddress.IPv4Network("192.168.0.1/64")
Traceback (most recent call last):
  ...
ipaddress.NetmaskValueError: '64' is not a valid netmask

그러나, 두 모듈 특정 예외 모두 부모 클래스로 ValueError를 가지므로, 특정 유형의 에러에 관심이 없다면, 여전히 다음과 같은 코드를 작성할 수 있습니다:

try:
    network = ipaddress.IPv4Network(address)
except ValueError:
    print('address/netmask is invalid for IPv4:', address)

DTrace와 SystemTap으로 CPython 계측하기

저자:

David Malcolm

저자:

Łukasz Langa

DTrace와 SystemTap은 컴퓨터 시스템의 프로세스가 하는 일을 검사할 수 있는 모니터링 도구입니다. 둘 다 도메인 특정 언어를 사용하여 다음과 같은 작업을 하는 스크립트를 작성할 수 있도록 합니다:

관찰할 프로세스를 걸러내기

관심 있는 프로세스에서 자료를 수집하기

데이터에 대한 보고서를 생성하기

파이썬 3.6부터, CPython은 DTrace나 SystemTap 스크립트에서 볼 수 있는 “마커(markers)”(“프로브(probes)”라고도 합니다)를 내장하도록 빌드할 수 있어서, 시스템에서 CPython 프로세스가 수행하고 있는 작업을 쉽게 관찰할 수 있습니다.

CPython 구현 상세: DTrace 마커는 CPython 인터프리터의 구현 세부 사항입니다. CPython 버전 간의 프로브 호환성에 대한 보장은 없습니다. CPython 버전을 변경할 때 경고 없이 DTrace 스크립트가 작동하지 않거나 올바르게 작동하지 않을 수 있습니다.

정적 마커 활성화하기

macOS는 DTrace를 기본적으로 지원합니다. 리눅스에서는, SystemTap을 위한 마커를 내장하도록 CPython을 빌드하려면, SystemTap 개발 도구를 설치해야 합니다.

리눅스 기계에서, 이렇게 하면 됩니다:

$ yum install systemtap-sdt-devel

또는:

$ sudo apt-get install systemtap-sdt-dev

CPython must then be configured with the --with-dtrace option:

checking for --with-dtrace... yes

macOS에서, 배경에서 파이썬 프로세스를 실행하고 파이썬 공급자가 제공 한 모든 프로브를 나열하여 사용 가능한 DTrace 프로브를 나열할 수 있습니다:

$ python3.6 -q &
$ sudo dtrace -l -P python$!  # or: dtrace -l -m python3.6

   ID   PROVIDER            MODULE                          FUNCTION NAME
29564 python18035        python3.6          _PyEval_EvalFrameDefault function-entry
29565 python18035        python3.6             dtrace_function_entry function-entry
29566 python18035        python3.6          _PyEval_EvalFrameDefault function-return
29567 python18035        python3.6            dtrace_function_return function-return
29568 python18035        python3.6                           collect gc-done
29569 python18035        python3.6                           collect gc-start
29570 python18035        python3.6          _PyEval_EvalFrameDefault line
29571 python18035        python3.6                 maybe_dtrace_line line

리눅스에서, “.note.stapsdt” 섹션이 있는지 확인하여 빌드 된 바이너리에 SystemTap 정적 마커가 있는지 확인할 수 있습니다.

$ readelf -S ./python | grep .note.stapsdt
[30] .note.stapsdt        NOTE         0000000000000000 00308d78

If you’ve built Python as a shared library (with the --enable-shared configure option), you need to look instead within the shared library. For example:

$ readelf -S libpython3.3dm.so.1.0 | grep .note.stapsdt
[29] .note.stapsdt        NOTE         0000000000000000 00365b68

충분히 최신의 readelf는 메타 데이터를 인쇄할 수 있습니다:

$ readelf -n ./python

Displaying notes found at file offset 0x00000254 with length 0x00000020:
    Owner                 Data size          Description
    GNU                  0x00000010          NT_GNU_ABI_TAG (ABI version tag)
        OS: Linux, ABI: 2.6.32

Displaying notes found at file offset 0x00000274 with length 0x00000024:
    Owner                 Data size          Description
    GNU                  0x00000014          NT_GNU_BUILD_ID (unique build ID bitstring)
        Build ID: df924a2b08a7e89f6e11251d4602022977af2670

Displaying notes found at file offset 0x002d6c30 with length 0x00000144:
    Owner                 Data size          Description
    stapsdt              0x00000031          NT_STAPSDT (SystemTap probe descriptors)
        Provider: python
        Name: gc__start
        Location: 0x00000000004371c3, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf6
        Arguments: -4@%ebx
    stapsdt              0x00000030          NT_STAPSDT (SystemTap probe descriptors)
        Provider: python
        Name: gc__done
        Location: 0x00000000004374e1, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf8
        Arguments: -8@%rax
    stapsdt              0x00000045          NT_STAPSDT (SystemTap probe descriptors)
        Provider: python
        Name: function__entry
        Location: 0x000000000053db6c, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6be8
        Arguments: 8@%rbp 8@%r12 -4@%eax
    stapsdt              0x00000046          NT_STAPSDT (SystemTap probe descriptors)
        Provider: python
        Name: function__return
        Location: 0x000000000053dba8, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bea
        Arguments: 8@%rbp 8@%r12 -4@%eax

The above metadata contains information for SystemTap describing how it can patch strategically placed machine code instructions to enable the tracing hooks used by a SystemTap script.

정적 DTrace 프로브

다음 예제 DTrace 스크립트는 파이썬 스크립트의 호출/반환 계층 구조를 표시하는 데 사용할 수 있습니다. “start”라는 함수의 호출 내부에서만 추적합니다. 즉, 임포트 시점의 함수 호출은 나열되지 않습니다:

self int indent;

python$target:::function-entry
/copyinstr(arg1) == "start"/
{
        self->trace = 1;
}

python$target:::function-entry
/self->trace/
{
        printf("%d\t%*s:", timestamp, 15, probename);
        printf("%*s", self->indent, "");
        printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
        self->indent++;
}

python$target:::function-return
/self->trace/
{
        self->indent--;
        printf("%d\t%*s:", timestamp, 15, probename);
        printf("%*s", self->indent, "");
        printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
}

python$target:::function-return
/copyinstr(arg1) == "start"/
{
        self->trace = 0;
}

다음과 같은 식으로 호출할 수 있습니다:

$ sudo dtrace -q -s call_stack.d -c "python3.6 script.py"

출력은 이런 식입니다:

156641360502280  function-entry:call_stack.py:start:23
156641360518804  function-entry: call_stack.py:function_1:1
156641360532797  function-entry:  call_stack.py:function_3:9
156641360546807 function-return:  call_stack.py:function_3:10
156641360563367 function-return: call_stack.py:function_1:2
156641360578365  function-entry: call_stack.py:function_2:5
156641360591757  function-entry:  call_stack.py:function_1:1
156641360605556  function-entry:   call_stack.py:function_3:9
156641360617482 function-return:   call_stack.py:function_3:10
156641360629814 function-return:  call_stack.py:function_1:2
156641360642285 function-return: call_stack.py:function_2:6
156641360656770  function-entry: call_stack.py:function_3:9
156641360669707 function-return: call_stack.py:function_3:10
156641360687853  function-entry: call_stack.py:function_4:13
156641360700719 function-return: call_stack.py:function_4:14
156641360719640  function-entry: call_stack.py:function_5:18
156641360732567 function-return: call_stack.py:function_5:21
156641360747370 function-return:call_stack.py:start:28

정적 SystemTap 마커

SystemTap 통합을 사용하는 저수준의 방법은 정적 마커를 직접 사용하는 것입니다. 이를 포함하는 바이너리 파일을 명시적으로 지정해야 합니다.

예를 들어, 이 SystemTap 스크립트는 파이썬 스크립트의 호출/반환 계층 구조를 표시하는 데 사용할 수 있습니다:

probe process("python").mark("function__entry") {
     filename = user_string($arg1);
     funcname = user_string($arg2);
     lineno = $arg3;

     printf("%s => %s in %s:%d\\n",
            thread_indent(1), funcname, filename, lineno);
}

probe process("python").mark("function__return") {
    filename = user_string($arg1);
    funcname = user_string($arg2);
    lineno = $arg3;

    printf("%s <= %s in %s:%d\\n",
           thread_indent(-1), funcname, filename, lineno);
}

다음과 같은 식으로 호출할 수 있습니다:

$ stap \
  show-call-hierarchy.stp \
  -c "./python test.py"

출력은 이런 식입니다:

11408 python(8274):        => __contains__ in Lib/_abcoll.py:362
11414 python(8274):         => __getitem__ in Lib/os.py:425
11418 python(8274):          => encode in Lib/os.py:490
11424 python(8274):          <= encode in Lib/os.py:493
11428 python(8274):         <= __getitem__ in Lib/os.py:426
11433 python(8274):        <= __contains__ in Lib/_abcoll.py:366

이때 열은 다음과 같습니다:

스크립트 시작으로부터 마이크로초 단위의 시간

실행 파일의 이름

프로세스의 PID

나머지는 스크립트가 실행될 때 호출/반환 계층 구조를 나타냅니다.

For a --enable-shared build of CPython, the markers are contained within the libpython shared library, and the probe’s dotted path needs to reflect this. For example, this line from the above example:

probe process("python").mark("function__entry") {

대신 이렇게 되어야 합니다:

probe process("python").library("libpython3.6dm.so.1.0").mark("function__entry") {

(assuming a debug build of CPython 3.6)

사용 가능한 정적 마커

function__entry(str filename, str funcname, int lineno)

이 마커는 파이썬 함수의 실행이 시작되었음을 나타냅니다. 순수 파이썬 (바이트 코드) 함수에서만 트리거 됩니다.

파일명, 함수 이름 및 줄 번호가 위치 인자로 추적 스크립트에 제공됩니다. $arg1, $arg2, $arg3를 사용하여 액세스해야 합니다:

$arg1 : (const char *) 파일명, user_string($arg1)를 사용하여 액세스할 수 있습니다

$arg2 : (const char *) 함수 이름, user_string($arg2)를 사용하여 액세스할 수 있습니다

$arg3 : int 줄 번호

function__return(str filename, str funcname, int lineno)

This marker is the converse of function__entry(), and indicates that execution of a Python function has ended (either via return, or via an exception). It is only triggered for pure-Python (bytecode) functions.

The arguments are the same as for function__entry()

line(str filename, str funcname, int lineno)

이 마커는 파이썬 줄이 실행되려고 함을 나타냅니다. 파이썬 프로파일러를 사용하는 줄 단위 추적과 동등합니다. C 함수 내에서는 트리거 되지 않습니다.

The arguments are the same as for function__entry().

gc__start(int generation)

Fires when the Python interpreter starts a garbage collection cycle. arg0 is the generation to scan, like gc.collect().

gc__done(long collected)

파이썬 인터프리터가 가비지 수집 사이클을 끝낼 때 발생합니다. arg0은 수집된 객체 수입니다.

import__find__load__start(str modulename)

importlib가 모듈을 찾고 로드하기 전에 발생합니다. arg0은 모듈 이름입니다.

Added in version 3.7.

import__find__load__done(str modulename, int found)

importlib의 모듈을 찾고 로드하는 함수가 호출 된 후에 발생합니다. arg0은 모듈 이름이고, arg1은 모듈이 성공적으로 로드되었는지를 나타냅니다.

Added in version 3.7.

audit(str event, void *tuple)

sys.audit()나 PySys_Audit()가 호출될 때 발생합니다. arg0는 C 문자열로 된 이벤트 이름이고, arg1은 튜플 객체를 가리키는 PyObject 포인터입니다.

Added in version 3.8.

SystemTap 탭셋

SystemTap 통합을 사용하는 고수준의 방법은 “탭셋(tapset)”을 사용하는 것입니다: SystemTap의 라이브러리에 해당하는 것입니다, 정적 마커의 저수준 세부 정보를 숨깁니다.

다음은 CPython의 비공유 빌드에 기반한 탭셋 파일입니다:

/*
   Provide a higher-level wrapping around the function__entry and
   function__return markers:
 \*/
probe python.function.entry = process("python").mark("function__entry")
{
    filename = user_string($arg1);
    funcname = user_string($arg2);
    lineno = $arg3;
    frameptr = $arg4
}
probe python.function.return = process("python").mark("function__return")
{
    filename = user_string($arg1);
    funcname = user_string($arg2);
    lineno = $arg3;
    frameptr = $arg4
}

이 파일을 SystemTap의 tapset 디렉터리(예를 들어, /usr/share/systemtap/tapset)에 설치하면, 다음과 같은 추가 프로브 포인트를 사용할 수 있습니다:

python.function.entry(str filename, str funcname, int lineno, frameptr)

이 프로브 포인트는 파이썬 함수의 실행이 시작되었음을 나타냅니다. 순수 파이썬 (바이트 코드) 함수에서만 트리거 됩니다.

python.function.return(str filename, str funcname, int lineno, frameptr)

이 프로브 포인트는 python.function.return의 반대이며, 파이썬 함수의 실행이 종료되었음을 나타냅니다 (return를 통해서나 예외를 통해). 순수 파이썬 (바이트 코드) 함수에서만 트리거 됩니다.

예제

이 SystemTap 스크립트는 위의 탭셋을 사용하여, 정적 마커의 이름을 직접 지정하지 않고도, 파이썬 함수 호출 계층 구조를 추적하는 위의 예제를 보다 명확하게 구현합니다.:

probe python.function.entry
{
  printf("%s => %s in %s:%d\n",
         thread_indent(1), funcname, filename, lineno);
}

probe python.function.return
{
  printf("%s <= %s in %s:%d\n",
         thread_indent(-1), funcname, filename, lineno);
}

The following script uses the tapset above to provide a top-like view of all running CPython code, showing the top 20 most frequently entered bytecode frames, each second, across the whole system:

global fn_calls;

probe python.function.entry
{
    fn_calls[pid(), filename, funcname, lineno] += 1;
}

probe timer.ms(1000) {
    printf("\033[2J\033[1;1H") /* clear screen \*/
    printf("%6s %80s %6s %30s %6s\n",
           "PID", "FILENAME", "LINE", "FUNCTION", "CALLS")
    foreach ([pid, filename, funcname, lineno] in fn_calls- limit 20) {
        printf("%6d %80s %6d %30s %6d\n",
            pid, filename, lineno, funcname,
            fn_calls[pid, filename, funcname, lineno]);
    }
    delete fn_calls;
}

Python support for the Linux perf profiler

author:

Pablo Galindo

The Linux perf profiler [https://perf.wiki.kernel.org] is a very powerful tool that allows you to profile and obtain information about the performance of your application. perf also has a very vibrant ecosystem of tools that aid with the analysis of the data that it produces.

The main problem with using the perf profiler with Python applications is that perf only gets information about native symbols, that is, the names of functions and procedures written in C. This means that the names and file names of Python functions in your code will not appear in the output of perf.

Since Python 3.12, the interpreter can run in a special mode that allows Python functions to appear in the output of the perf profiler. When this mode is enabled, the interpreter will interpose a small piece of code compiled on the fly before the execution of every Python function and it will teach perf the relationship between this piece of code and the associated Python function using perf map files.

참고

Support for the perf profiler is currently only available for Linux on select architectures. Check the output of the configure build step or check the output of python -m sysconfig | grep HAVE_PERF_TRAMPOLINE to see if your system is supported.

For example, consider the following script:

def foo(n):
    result = 0
    for _ in range(n):
        result += 1
    return result

def bar(n):
    foo(n)

def baz(n):
    bar(n)

if __name__ == "__main__":
    baz(1000000)

We can run perf to sample CPU stack traces at 9999 hertz:

$ perf record -F 9999 -g -o perf.data python my_script.py

Then we can use perf report to analyze the data:

$ perf report --stdio -n -g

# Children      Self       Samples  Command     Shared Object       Symbol
# ........  ........  ............  ..........  ..................  ..........................................
#
    91.08%     0.00%             0  python.exe  python.exe          [.] _start
            |
            ---_start
            |
                --90.71%--__libc_start_main
                        Py_BytesMain
                        |
                        |--56.88%--pymain_run_python.constprop.0
                        |          |
                        |          |--56.13%--_PyRun_AnyFileObject
                        |          |          _PyRun_SimpleFileObject
                        |          |          |
                        |          |          |--55.02%--run_mod
                        |          |          |          |
                        |          |          |           --54.65%--PyEval_EvalCode
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     |
                        |          |          |                     |--51.67%--_PyEval_EvalFrameDefault
                        |          |          |                     |          |
                        |          |          |                     |          |--11.52%--_PyLong_Add
                        |          |          |                     |          |          |
                        |          |          |                     |          |          |--2.97%--_PyObject_Malloc
...

As you can see, the Python functions are not shown in the output, only _PyEval_EvalFrameDefault (the function that evaluates the Python bytecode) shows up. Unfortunately that’s not very useful because all Python functions use the same C function to evaluate bytecode so we cannot know which Python function corresponds to which bytecode-evaluating function.

Instead, if we run the same experiment with perf support enabled we get:

$ perf report --stdio -n -g

# Children      Self       Samples  Command     Shared Object       Symbol
# ........  ........  ............  ..........  ..................  .....................................................................
#
    90.58%     0.36%             1  python.exe  python.exe          [.] _start
            |
            ---_start
            |
                --89.86%--__libc_start_main
                        Py_BytesMain
                        |
                        |--55.43%--pymain_run_python.constprop.0
                        |          |
                        |          |--54.71%--_PyRun_AnyFileObject
                        |          |          _PyRun_SimpleFileObject
                        |          |          |
                        |          |          |--53.62%--run_mod
                        |          |          |          |
                        |          |          |           --53.26%--PyEval_EvalCode
                        |          |          |                     py::<module>:/src/script.py
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     py::baz:/src/script.py
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     py::bar:/src/script.py
                        |          |          |                     _PyEval_EvalFrameDefault
                        |          |          |                     PyObject_Vectorcall
                        |          |          |                     _PyEval_Vector
                        |          |          |                     py::foo:/src/script.py
                        |          |          |                     |
                        |          |          |                     |--51.81%--_PyEval_EvalFrameDefault
                        |          |          |                     |          |
                        |          |          |                     |          |--13.77%--_PyLong_Add
                        |          |          |                     |          |          |
                        |          |          |                     |          |          |--3.26%--_PyObject_Malloc

How to enable perf profiling support

perf profiling support can be enabled either from the start using the environment variable PYTHONPERFSUPPORT or the -X perf option, or dynamically using sys.activate_stack_trampoline() and sys.deactivate_stack_trampoline().

The sys functions take precedence over the -X option, the -X option takes precedence over the environment variable.

Example, using the environment variable:

$ PYTHONPERFSUPPORT=1 perf record -F 9999 -g -o perf.data python script.py
$ perf report -g -i perf.data

Example, using the -X option:

$ perf record -F 9999 -g -o perf.data python -X perf script.py
$ perf report -g -i perf.data

Example, using the sys APIs in file example.py:

import sys

sys.activate_stack_trampoline("perf")
do_profiled_stuff()
sys.deactivate_stack_trampoline()

non_profiled_stuff()

…then:

$ perf record -F 9999 -g -o perf.data python ./example.py
$ perf report -g -i perf.data

How to obtain the best results

For best results, Python should be compiled with CFLAGS="-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer" as this allows profilers to unwind using only the frame pointer and not on DWARF debug information. This is because as the code that is interposed to allow perf support is dynamically generated it doesn’t have any DWARF debugging information available.

You can check if your system has been compiled with this flag by running:

$ python -m sysconfig | grep 'no-omit-frame-pointer'

If you don’t see any output it means that your interpreter has not been compiled with frame pointers and therefore it may not be able to show Python functions in the output of perf.

How to work without frame pointers

If you are working with a Python interpreter that has been compiled without frame pointers, you can still use the perf profiler, but the overhead will be a bit higher because Python needs to generate unwinding information for every Python function call on the fly. Additionally, perf will take more time to process the data because it will need to use the DWARF debugging information to unwind the stack and this is a slow process.

To enable this mode, you can use the environment variable PYTHON_PERF_JIT_SUPPORT or the -X perf_jit option, which will enable the JIT mode for the perf profiler.

참고

Due to a bug in the perf tool, only perf versions higher than v6.8 will work with the JIT mode. The fix was also backported to the v6.7.2 version of the tool.

Note that when checking the version of the perf tool (which can be done by running perf version) you must take into account that some distros add some custom version numbers including a - character. This means that perf 6.7-3 is not necessarily perf 6.7.3.

When using the perf JIT mode, you need an extra step before you can run perf report. You need to call the perf inject command to inject the JIT information into the perf.data file.:

$ perf record -F 9999 -g --call-graph dwarf -o perf.data python -Xperf_jit my_script.py
$ perf inject -i perf.data --jit --output perf.jit.data
$ perf report -g -i perf.jit.data

or using the environment variable:

$ PYTHON_PERF_JIT_SUPPORT=1 perf record -F 9999 -g --call-graph dwarf -o perf.data python my_script.py
$ perf inject -i perf.data --jit --output perf.jit.data
$ perf report -g -i perf.jit.data

perf inject --jit command will read perf.data, automatically pick up the perf dump file that Python creates (in /tmp/perf-$PID.dump), and then create perf.jit.data which merges all the JIT information together. It should also create a lot of jitted-XXXX-N.so files in the current directory which are ELF images for all the JIT trampolines that were created by Python.

경고

Notice that when using --call-graph dwarf the perf tool will take snapshots of the stack of the process being profiled and save the information in the perf.data file. By default the size of the stack dump is 8192 bytes but the user can change the size by passing the size after comma like --call-graph dwarf,4096. The size of the stack dump is important because if the size is too small perf will not be able to unwind the stack and the output will be incomplete. On the other hand, if the size is too big, then perf won’t be able to sample the process as frequently as it would like as the overhead will be higher.

Annotations Best Practices

author:

Larry Hastings

Abstract

This document is designed to encapsulate the best practices for working with annotations dicts. If you write Python code that examines __annotations__ on Python objects, we encourage you to follow the guidelines described below.

The document is organized into four sections: best practices for accessing the annotations of an object in Python versions 3.10 and newer, best practices for accessing the annotations of an object in Python versions 3.9 and older, other best practices for __annotations__ that apply to any Python version, and quirks of __annotations__.

Note that this document is specifically about working with __annotations__, not uses for annotations. If you’re looking for information on how to use “type hints” in your code, please see the typing module.

Accessing The Annotations Dict Of An Object In Python 3.10 And Newer

Python 3.10 adds a new function to the standard library: inspect.get_annotations(). In Python versions 3.10 through 3.13, calling this function is the best practice for accessing the annotations dict of any object that supports annotations. This function can also “un-stringize” stringized annotations for you.

In Python 3.14, there is a new annotationlib module with functionality for working with annotations. This includes a annotationlib.get_annotations() function, which supersedes inspect.get_annotations().

If for some reason inspect.get_annotations() isn’t viable for your use case, you may access the __annotations__ data member manually. Best practice for this changed in Python 3.10 as well: as of Python 3.10, o.__annotations__ is guaranteed to always work on Python functions, classes, and modules. If you’re certain the object you’re examining is one of these three specific objects, you may simply use o.__annotations__ to get at the object’s annotations dict.

However, other types of callables–for example, callables created by functools.partial()–may not have an __annotations__ attribute defined. When accessing the __annotations__ of a possibly unknown object, best practice in Python versions 3.10 and newer is to call getattr() with three arguments, for example getattr(o, '__annotations__', None).

Before Python 3.10, accessing __annotations__ on a class that defines no annotations but that has a parent class with annotations would return the parent’s __annotations__. In Python 3.10 and newer, the child class’s annotations will be an empty dict instead.

Accessing The Annotations Dict Of An Object In Python 3.9 And Older

In Python 3.9 and older, accessing the annotations dict of an object is much more complicated than in newer versions. The problem is a design flaw in these older versions of Python, specifically to do with class annotations.

Best practice for accessing the annotations dict of other objects–functions, other callables, and modules–is the same as best practice for 3.10, assuming you aren’t calling inspect.get_annotations(): you should use three-argument getattr() to access the object’s __annotations__ attribute.

Unfortunately, this isn’t best practice for classes. The problem is that, since __annotations__ is optional on classes, and because classes can inherit attributes from their base classes, accessing the __annotations__ attribute of a class may inadvertently return the annotations dict of a base class. As an example:

class Base:
    a: int = 3
    b: str = 'abc'

class Derived(Base):
    pass

print(Derived.__annotations__)

This will print the annotations dict from Base, not Derived.

Your code will have to have a separate code path if the object you’re examining is a class (isinstance(o, type)). In that case, best practice relies on an implementation detail of Python 3.9 and before: if a class has annotations defined, they are stored in the class’s __dict__ dictionary. Since the class may or may not have annotations defined, best practice is to call the get() method on the class dict.

To put it all together, here is some sample code that safely accesses the __annotations__ attribute on an arbitrary object in Python 3.9 and before:

if isinstance(o, type):
    ann = o.__dict__.get('__annotations__', None)
else:
    ann = getattr(o, '__annotations__', None)

After running this code, ann should be either a dictionary or None. You’re encouraged to double-check the type of ann using isinstance() before further examination.

Note that some exotic or malformed type objects may not have a __dict__ attribute, so for extra safety you may also wish to use getattr() to access __dict__.

Manually Un-Stringizing Stringized Annotations

In situations where some annotations may be “stringized”, and you wish to evaluate those strings to produce the Python values they represent, it really is best to call inspect.get_annotations() to do this work for you.

If you’re using Python 3.9 or older, or if for some reason you can’t use inspect.get_annotations(), you’ll need to duplicate its logic. You’re encouraged to examine the implementation of inspect.get_annotations() in the current Python version and follow a similar approach.

In a nutshell, if you wish to evaluate a stringized annotation on an arbitrary object o:

If o is a module, use o.__dict__ as the globals when calling eval().

If o is a class, use sys.modules[o.__module__].__dict__ as the globals, and dict(vars(o)) as the locals, when calling eval().

If o is a wrapped callable using functools.update_wrapper(), functools.wraps(), or functools.partial(), iteratively unwrap it by accessing either o.__wrapped__ or o.func as appropriate, until you have found the root unwrapped function.

If o is a callable (but not a class), use o.__globals__ as the globals when calling eval().

However, not all string values used as annotations can be successfully turned into Python values by eval(). String values could theoretically contain any valid string, and in practice there are valid use cases for type hints that require annotating with string values that specifically can’t be evaluated. For example:

PEP 604 [https://peps.python.org/pep-0604/] union types using |, before support for this was added to Python 3.10.

Definitions that aren’t needed at runtime, only imported when typing.TYPE_CHECKING is true.

If eval() attempts to evaluate such values, it will fail and raise an exception. So, when designing a library API that works with annotations, it’s recommended to only attempt to evaluate string values when explicitly requested to by the caller.

Best Practices For __annotations__ In Any Python Version

You should avoid assigning to the __annotations__ member of objects directly. Let Python manage setting __annotations__.

If you do assign directly to the __annotations__ member of an object, you should always set it to a dict object.

You should avoid accessing __annotations__ directly on any object. Instead, use annotationlib.get_annotations() (Python 3.14+) or inspect.get_annotations() (Python 3.10+).

If you do directly access the __annotations__ member of an object, you should ensure that it’s a dictionary before attempting to examine its contents.

You should avoid modifying __annotations__ dicts.

You should avoid deleting the __annotations__ attribute of an object.

__annotations__ Quirks

In all versions of Python 3, function objects lazy-create an annotations dict if no annotations are defined on that object. You can delete the __annotations__ attribute using del fn.__annotations__, but if you then access fn.__annotations__ the object will create a new empty dict that it will store and return as its annotations. Deleting the annotations on a function before it has lazily created its annotations dict will throw an AttributeError; using del fn.__annotations__ twice in a row is guaranteed to always throw an AttributeError.

Everything in the above paragraph also applies to class and module objects in Python 3.10 and newer.

In all versions of Python 3, you can set __annotations__ on a function object to None. However, subsequently accessing the annotations on that object using fn.__annotations__ will lazy-create an empty dictionary as per the first paragraph of this section. This is not true of modules and classes, in any Python version; those objects permit setting __annotations__ to any Python value, and will retain whatever value is set.

If Python stringizes your annotations for you (using from __future__ import annotations), and you specify a string as an annotation, the string will itself be quoted. In effect the annotation is quoted twice. For example:

from __future__ import annotations
def foo(a: "str"): pass

print(foo.__annotations__)

This prints {'a': "'str'"}. This shouldn’t really be considered a “quirk”; it’s mentioned here simply because it might be surprising.

If you use a class with a custom metaclass and access __annotations__ on the class, you may observe unexpected behavior; see 749 [https://peps.python.org/pep-0749/#pep749-metaclasses] for some examples. You can avoid these quirks by using annotationlib.get_annotations() on Python 3.14+ or inspect.get_annotations() on Python 3.10+. On earlier versions of Python, you can avoid these bugs by accessing the annotations from the class’s __dict__ (e.g., cls.__dict__.get('__annotations__', None)).

Isolating Extension Modules

Abstract

Traditionally, state belonging to Python extension modules was kept in C static variables, which have process-wide scope. This document describes problems of such per-process state and shows a safer way: per-module state.

The document also describes how to switch to per-module state where possible. This transition involves allocating space for that state, potentially switching from static types to heap types, and—perhaps most importantly—accessing per-module state from code.

Who should read this

This guide is written for maintainers of C-API extensions who would like to make that extension safer to use in applications where Python itself is used as a library.

Background

An interpreter is the context in which Python code runs. It contains configuration (e.g. the import path) and runtime state (e.g. the set of imported modules).

Python supports running multiple interpreters in one process. There are two cases to think about—users may run interpreters:

in sequence, with several Py_InitializeEx()/Py_FinalizeEx() cycles, and

in parallel, managing “sub-interpreters” using Py_NewInterpreter()/Py_EndInterpreter().

Both cases (and combinations of them) would be most useful when embedding Python within a library. Libraries generally shouldn’t make assumptions about the application that uses them, which include assuming a process-wide “main Python interpreter”.

Historically, Python extension modules don’t handle this use case well. Many extension modules (and even some stdlib modules) use per-process global state, because C static variables are extremely easy to use. Thus, data that should be specific to an interpreter ends up being shared between interpreters. Unless the extension developer is careful, it is very easy to introduce edge cases that lead to crashes when a module is loaded in more than one interpreter in the same process.

Unfortunately, per-interpreter state is not easy to achieve. Extension authors tend to not keep multiple interpreters in mind when developing, and it is currently cumbersome to test the behavior.

Enter Per-Module State

Instead of focusing on per-interpreter state, Python’s C API is evolving to better support the more granular per-module state. This means that C-level data should be attached to a module object. Each interpreter creates its own module object, keeping the data separate. For testing the isolation, multiple module objects corresponding to a single extension can even be loaded in a single interpreter.

Per-module state provides an easy way to think about lifetime and resource ownership: the extension module will initialize when a module object is created, and clean up when it’s freed. In this regard, a module is just like any other PyObject*; there are no “on interpreter shutdown” hooks to think—or forget—about.

Note that there are use cases for different kinds of “globals”: per-process, per-interpreter, per-thread or per-task state. With per-module state as the default, these are still possible, but you should treat them as exceptional cases: if you need them, you should give them additional care and testing. (Note that this guide does not cover them.)

Isolated Module Objects

The key point to keep in mind when developing an extension module is that several module objects can be created from a single shared library. For example:

>>> import sys
>>> import binascii
>>> old_binascii = binascii
>>> del sys.modules['binascii']
>>> import binascii  # create a new module object
>>> old_binascii == binascii
False

As a rule of thumb, the two modules should be completely independent. All objects and state specific to the module should be encapsulated within the module object, not shared with other module objects, and cleaned up when the module object is deallocated. Since this just is a rule of thumb, exceptions are possible (see Managing Global State), but they will need more thought and attention to edge cases.

While some modules could do with less stringent restrictions, isolated modules make it easier to set clear expectations and guidelines that work across a variety of use cases.

Surprising Edge Cases

Note that isolated modules do create some surprising edge cases. Most notably, each module object will typically not share its classes and exceptions with other similar modules. Continuing from the example above, note that old_binascii.Error and binascii.Error are separate objects. In the following code, the exception is not caught:

>>> old_binascii.Error == binascii.Error
False
>>> try:
...     old_binascii.unhexlify(b'qwertyuiop')
... except binascii.Error:
...     print('boo')
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
binascii.Error: Non-hexadecimal digit found

This is expected. Notice that pure-Python modules behave the same way: it is a part of how Python works.

The goal is to make extension modules safe at the C level, not to make hacks behave intuitively. Mutating sys.modules “manually” counts as a hack.

Making Modules Safe with Multiple Interpreters

Managing Global State

Sometimes, the state associated with a Python module is not specific to that module, but to the entire process (or something else “more global” than a module). For example:

The readline module manages the terminal.

A module running on a circuit board wants to control the on-board LED.

In these cases, the Python module should provide access to the global state, rather than own it. If possible, write the module so that multiple copies of it can access the state independently (along with other libraries, whether for Python or other languages). If that is not possible, consider explicit locking.

If it is necessary to use process-global state, the simplest way to avoid issues with multiple interpreters is to explicitly prevent a module from being loaded more than once per process—see Opt-Out: Limiting to One Module Object per Process.

Managing Per-Module State

To use per-module state, use multi-phase extension module initialization. This signals that your module supports multiple interpreters correctly.

Set PyModuleDef.m_size to a positive number to request that many bytes of storage local to the module. Usually, this will be set to the size of some module-specific struct, which can store all of the module’s C-level state. In particular, it is where you should put pointers to classes (including exceptions, but excluding static types) and settings (e.g. csv’s field_size_limit) which the C code needs to function.

참고

Another option is to store state in the module’s __dict__, but you must avoid crashing when users modify __dict__ from Python code. This usually means error- and type-checking at the C level, which is easy to get wrong and hard to test sufficiently.

However, if module state is not needed in C code, storing it in __dict__ only is a good idea.

If the module state includes PyObject pointers, the module object must hold references to those objects and implement the module-level hooks m_traverse, m_clear and m_free. These work like tp_traverse, tp_clear and tp_free of a class. Adding them will require some work and make the code longer; this is the price for modules which can be unloaded cleanly.

An example of a module with per-module state is currently available as xxlimited [https://github.com/python/cpython/blob/master/Modules/xxlimited.c]; example module initialization shown at the bottom of the file.

Opt-Out: Limiting to One Module Object per Process

A non-negative PyModuleDef.m_size signals that a module supports multiple interpreters correctly. If this is not yet the case for your module, you can explicitly make your module loadable only once per process. For example:

static int loaded = 0;

static int
exec_module(PyObject* module)
{
    if (loaded) {
        PyErr_SetString(PyExc_ImportError,
                        "cannot load module more than once per process");
        return -1;
    }
    loaded = 1;
    // ... rest of initialization
}

Module State Access from Functions

Accessing the state from module-level functions is straightforward. Functions get the module object as their first argument; for extracting the state, you can use PyModule_GetState:

static PyObject *
func(PyObject *module, PyObject *args)
{
    my_struct *state = (my_struct*)PyModule_GetState(module);
    if (state == NULL) {
        return NULL;
    }
    // ... rest of logic
}

참고

PyModule_GetState may return NULL without setting an exception if there is no module state, i.e. PyModuleDef.m_size was zero. In your own module, you’re in control of m_size, so this is easy to prevent.

Heap Types

Traditionally, types defined in C code are static; that is, static PyTypeObject structures defined directly in code and initialized using PyType_Ready().

Such types are necessarily shared across the process. Sharing them between module objects requires paying attention to any state they own or access. To limit the possible issues, static types are immutable at the Python level: for example, you can’t set str.myattribute = 123.

CPython 구현 상세: Sharing truly immutable objects between interpreters is fine, as long as they don’t provide access to mutable objects. However, in CPython, every Python object has a mutable implementation detail: the reference count. Changes to the refcount are guarded by the GIL. Thus, code that shares any Python objects across interpreters implicitly depends on CPython’s current, process-wide GIL.

Because they are immutable and process-global, static types cannot access “their” module state. If any method of such a type requires access to module state, the type must be converted to a heap-allocated type, or heap type for short. These correspond more closely to classes created by Python’s class statement.

For new modules, using heap types by default is a good rule of thumb.

Changing Static Types to Heap Types

Static types can be converted to heap types, but note that the heap type API was not designed for “lossless” conversion from static types—that is, creating a type that works exactly like a given static type. So, when rewriting the class definition in a new API, you are likely to unintentionally change a few details (e.g. pickleability or inherited slots). Always test the details that are important to you.

Watch out for the following two points in particular (but note that this is not a comprehensive list):

Unlike static types, heap type objects are mutable by default. Use the Py_TPFLAGS_IMMUTABLETYPE flag to prevent mutability.

Heap types inherit tp_new by default, so it may become possible to instantiate them from Python code. You can prevent this with the Py_TPFLAGS_DISALLOW_INSTANTIATION flag.

Defining Heap Types

Heap types can be created by filling a PyType_Spec structure, a description or “blueprint” of a class, and calling PyType_FromModuleAndSpec() to construct a new class object.

참고

Other functions, like PyType_FromSpec(), can also create heap types, but PyType_FromModuleAndSpec() associates the module with the class, allowing access to the module state from methods.

The class should generally be stored in both the module state (for safe access from C) and the module’s __dict__ (for access from Python code).

Garbage-Collection Protocol

Instances of heap types hold a reference to their type. This ensures that the type isn’t destroyed before all its instances are, but may result in reference cycles that need to be broken by the garbage collector.

To avoid memory leaks, instances of heap types must implement the garbage collection protocol. That is, heap types should:

Have the Py_TPFLAGS_HAVE_GC flag.

Define a traverse function using Py_tp_traverse, which visits the type (e.g. using Py_VISIT(Py_TYPE(self))).

Please refer to the documentation of Py_TPFLAGS_HAVE_GC and tp_traverse for additional considerations.

The API for defining heap types grew organically, leaving it somewhat awkward to use in its current state. The following sections will guide you through common issues.

tp_traverse in Python 3.8 and lower

The requirement to visit the type from tp_traverse was added in Python 3.9. If you support Python 3.8 and lower, the traverse function must not visit the type, so it must be more complicated:

static int my_traverse(PyObject *self, visitproc visit, void *arg)
{
    if (Py_Version >= 0x03090000) {
        Py_VISIT(Py_TYPE(self));
    }
    return 0;
}

Unfortunately, Py_Version was only added in Python 3.11. As a replacement, use:

PY_VERSION_HEX, if not using the stable ABI, or

sys.version_info (via PySys_GetObject() and PyArg_ParseTuple()).

Delegating tp_traverse

If your traverse function delegates to the tp_traverse of its base class (or another type), ensure that Py_TYPE(self) is visited only once. Note that only heap type are expected to visit the type in tp_traverse.

For example, if your traverse function includes:

base->tp_traverse(self, visit, arg)

…and base may be a static type, then it should also include:

if (base->tp_flags & Py_TPFLAGS_HEAPTYPE) {
    // a heap type's tp_traverse already visited Py_TYPE(self)
} else {
    if (Py_Version >= 0x03090000) {
        Py_VISIT(Py_TYPE(self));
    }
}

It is not necessary to handle the type’s reference count in tp_new and tp_clear.

Defining tp_dealloc

If your type has a custom tp_dealloc function, it needs to:

call PyObject_GC_UnTrack() before any fields are invalidated, and

decrement the reference count of the type.

To keep the type valid while tp_free is called, the type’s refcount needs to be decremented after the instance is deallocated. For example:

static void my_dealloc(PyObject *self)
{
    PyObject_GC_UnTrack(self);
    ...
    PyTypeObject *type = Py_TYPE(self);
    type->tp_free(self);
    Py_DECREF(type);
}

The default tp_dealloc function does this, so if your type does not override tp_dealloc you don’t need to add it.

Not overriding tp_free

The tp_free slot of a heap type must be set to PyObject_GC_Del(). This is the default; do not override it.

Avoiding PyObject_New

GC-tracked objects need to be allocated using GC-aware functions.

If you use use PyObject_New() or PyObject_NewVar():

Get and call type’s tp_alloc slot, if possible. That is, replace TYPE *o = PyObject_New(TYPE, typeobj) with:

TYPE *o = typeobj->tp_alloc(typeobj, 0);

Replace o = PyObject_NewVar(TYPE, typeobj, size) with the same, but use size instead of the 0.

If the above is not possible (e.g. inside a custom tp_alloc), call PyObject_GC_New() or PyObject_GC_NewVar():

TYPE *o = PyObject_GC_New(TYPE, typeobj);

TYPE *o = PyObject_GC_NewVar(TYPE, typeobj, size);

Module State Access from Classes

If you have a type object defined with PyType_FromModuleAndSpec(), you can call PyType_GetModule() to get the associated module, and then PyModule_GetState() to get the module’s state.

To save a some tedious error-handling boilerplate code, you can combine these two steps with PyType_GetModuleState(), resulting in:

my_struct *state = (my_struct*)PyType_GetModuleState(type);
if (state == NULL) {
    return NULL;
}

Module State Access from Regular Methods

Accessing the module-level state from methods of a class is somewhat more complicated, but is possible thanks to API introduced in Python 3.9. To get the state, you need to first get the defining class, and then get the module state from it.

The largest roadblock is getting the class a method was defined in, or that method’s “defining class” for short. The defining class can have a reference to the module it is part of.

Do not confuse the defining class with Py_TYPE(self). If the method is called on a subclass of your type, Py_TYPE(self) will refer to that subclass, which may be defined in different module than yours.

참고

The following Python code can illustrate the concept. Base.get_defining_class returns Base even if type(self) == Sub:

class Base:
    def get_type_of_self(self):
        return type(self)

    def get_defining_class(self):
        return __class__

class Sub(Base):
    pass

For a method to get its “defining class”, it must use the METH_METHOD | METH_FASTCALL | METH_KEYWORDS calling convention and the corresponding PyCMethod signature:

PyObject *PyCMethod(
    PyObject *self,               // object the method was called on
    PyTypeObject *defining_class, // defining class
    PyObject *const *args,        // C array of arguments
    Py_ssize_t nargs,             // length of "args"
    PyObject *kwnames)            // NULL, or dict of keyword arguments

Once you have the defining class, call PyType_GetModuleState() to get the state of its associated module.

For example:

static PyObject *
example_method(PyObject *self,
        PyTypeObject *defining_class,
        PyObject *const *args,
        Py_ssize_t nargs,
        PyObject *kwnames)
{
    my_struct *state = (my_struct*)PyType_GetModuleState(defining_class);
    if (state == NULL) {
        return NULL;
    }
    ... // rest of logic
}

PyDoc_STRVAR(example_method_doc, "...");

static PyMethodDef my_methods[] = {
    {"example_method",
      (PyCFunction)(void(*)(void))example_method,
      METH_METHOD|METH_FASTCALL|METH_KEYWORDS,
      example_method_doc}
    {NULL},
}

Module State Access from Slot Methods, Getters and Setters

참고

This is new in Python 3.11.

Slot methods—the fast C equivalents for special methods, such as nb_add for __add__ or tp_new for initialization—have a very simple API that doesn’t allow passing in the defining class, unlike with PyCMethod. The same goes for getters and setters defined with PyGetSetDef.

To access the module state in these cases, use the PyType_GetModuleByDef() function, and pass in the module definition. Once you have the module, call PyModule_GetState() to get the state:

PyObject *module = PyType_GetModuleByDef(Py_TYPE(self), &module_def);
my_struct *state = (my_struct*)PyModule_GetState(module);
if (state == NULL) {
    return NULL;
}

PyType_GetModuleByDef() works by searching the method resolution order (i.e. all superclasses) for the first superclass that has a corresponding module.

참고

In very exotic cases (inheritance chains spanning multiple modules created from the same definition), PyType_GetModuleByDef() might not return the module of the true defining class. However, it will always return a module with the same definition, ensuring a compatible C memory layout.

Lifetime of the Module State

When a module object is garbage-collected, its module state is freed. For each pointer to (a part of) the module state, you must hold a reference to the module object.

Usually this is not an issue, because types created with PyType_FromModuleAndSpec(), and their instances, hold a reference to the module. However, you must be careful in reference counting when you reference module state from other places, such as callbacks for external libraries.

Open Issues

Several issues around per-module state and heap types are still open.

Discussions about improving the situation are best held on the capi-sig mailing list [https://mail.python.org/mailman3/lists/capi-sig.python.org/].

Per-Class Scope

It is currently (as of Python 3.11) not possible to attach state to individual types without relying on CPython implementation details (which may change in the future—perhaps, ironically, to allow a proper solution for per-class scope).

Lossless Conversion to Heap Types

The heap type API was not designed for “lossless” conversion from static types; that is, creating a type that works exactly like a given static type.

timer file descriptor HOWTO

Release:

1.13

This HOWTO discusses Python’s support for the linux timer file descriptor.

Examples

The following example shows how to use a timer file descriptor to execute a function twice a second:

# Practical scripts should use really use a non-blocking timer,
# we use a blocking timer here for simplicity.
import os, time

# Create the timer file descriptor
fd = os.timerfd_create(time.CLOCK_REALTIME)

# Start the timer in 1 second, with an interval of half a second
os.timerfd_settime(fd, initial=1, interval=0.5)

try:
    # Process timer events four times.
    for _ in range(4):
        # read() will block until the timer expires
        _ = os.read(fd, 8)
        print("Timer expired")
finally:
    # Remember to close the timer file descriptor!
    os.close(fd)

To avoid the precision loss caused by the float type, timer file descriptors allow specifying initial expiration and interval in integer nanoseconds with _ns variants of the functions.

This example shows how epoll() can be used with timer file descriptors to wait until the file descriptor is ready for reading:

import os, time, select, socket, sys

# Create an epoll object
ep = select.epoll()

# In this example, use loopback address to send "stop" command to the server.
#
# $ telnet 127.0.0.1 1234
# Trying 127.0.0.1...
# Connected to 127.0.0.1.
# Escape character is '^]'.
# stop
# Connection closed by foreign host.
#
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(("127.0.0.1", 1234))
sock.setblocking(False)
sock.listen(1)
ep.register(sock, select.EPOLLIN)

# Create timer file descriptors in non-blocking mode.
num = 3
fds = []
for _ in range(num):
    fd = os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK)
    fds.append(fd)
    # Register the timer file descriptor for read events
    ep.register(fd, select.EPOLLIN)

# Start the timer with os.timerfd_settime_ns() in nanoseconds.
# Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc
for i, fd in enumerate(fds, start=1):
    one_sec_in_nsec = 10**9
    i = i * one_sec_in_nsec
    os.timerfd_settime_ns(fd, initial=i//4, interval=i//4)

timeout = 3
try:
    conn = None
    is_active = True
    while is_active:
        # Wait for the timer to expire for 3 seconds.
        # epoll.poll() returns a list of (fd, event) pairs.
        # fd is a file descriptor.
        # sock and conn[=returned value of socket.accept()] are socket objects, not file descriptors.
        # So use sock.fileno() and conn.fileno() to get the file descriptors.
        events = ep.poll(timeout)

        # If more than one timer file descriptors are ready for reading at once,
        # epoll.poll() returns a list of (fd, event) pairs.
        #
        # In this example settings,
        #    1st timer fires every 0.25 seconds in 0.25 seconds. (0.25, 0.5, 0.75, 1.0, ...)
        #    2nd timer every 0.5 seconds in 0.5 seconds. (0.5, 1.0, 1.5, 2.0, ...)
        #    3rd timer every 0.75 seconds in 0.75 seconds. (0.75, 1.5, 2.25, 3.0, ...)
        #
        #    In 0.25 seconds, only 1st timer fires.
        #    In 0.5 seconds, 1st timer and 2nd timer fires at once.
        #    In 0.75 seconds, 1st timer and 3rd timer fires at once.
        #    In 1.5 seconds, 1st timer, 2nd timer and 3rd timer fires at once.
        #
        # If a timer file descriptor is signaled more than once since
        # the last os.read() call, os.read() returns the number of signaled
        # as host order of class bytes.
        print(f"Signaled events={events}")
        for fd, event in events:
            if event & select.EPOLLIN:
                if fd == sock.fileno():
                    # Check if there is a connection request.
                    print(f"Accepting connection {fd}")
                    conn, addr = sock.accept()
                    conn.setblocking(False)
                    print(f"Accepted connection {conn} from {addr}")
                    ep.register(conn, select.EPOLLIN)
                elif conn and fd == conn.fileno():
                    # Check if there is data to read.
                    print(f"Reading data {fd}")
                    data = conn.recv(1024)
                    if data:
                        # You should catch UnicodeDecodeError exception for safety.
                        cmd = data.decode()
                        if cmd.startswith("stop"):
                            print(f"Stopping server")
                            is_active = False
                        else:
                            print(f"Unknown command: {cmd}")
                    else:
                        # No more data, close connection
                        print(f"Closing connection {fd}")
                        ep.unregister(conn)
                        conn.close()
                        conn = None
                elif fd in fds:
                    print(f"Reading timer {fd}")
                    count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder)
                    print(f"Timer {fds.index(fd) + 1} expired {count} times")
                else:
                    print(f"Unknown file descriptor {fd}")
finally:
    for fd in fds:
        ep.unregister(fd)
        os.close(fd)
    ep.close()

This example shows how select() can be used with timer file descriptors to wait until the file descriptor is ready for reading:

import os, time, select, socket, sys

# In this example, use loopback address to send "stop" command to the server.
#
# $ telnet 127.0.0.1 1234
# Trying 127.0.0.1...
# Connected to 127.0.0.1.
# Escape character is '^]'.
# stop
# Connection closed by foreign host.
#
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(("127.0.0.1", 1234))
sock.setblocking(False)
sock.listen(1)

# Create timer file descriptors in non-blocking mode.
num = 3
fds = [os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK)
       for _ in range(num)]
select_fds = fds + [sock]

# Start the timers with os.timerfd_settime() in seconds.
# Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc
for i, fd in enumerate(fds, start=1):
   os.timerfd_settime(fd, initial=i/4, interval=i/4)

timeout = 3
try:
    conn = None
    is_active = True
    while is_active:
       # Wait for the timer to expire for 3 seconds.
       # select.select() returns a list of file descriptors or objects.
       rfd, wfd, xfd = select.select(select_fds, select_fds, select_fds, timeout)
       for fd in rfd:
           if fd == sock:
               # Check if there is a connection request.
               print(f"Accepting connection {fd}")
               conn, addr = sock.accept()
               conn.setblocking(False)
               print(f"Accepted connection {conn} from {addr}")
               select_fds.append(conn)
           elif conn and fd == conn:
               # Check if there is data to read.
               print(f"Reading data {fd}")
               data = conn.recv(1024)
               if data:
                   # You should catch UnicodeDecodeError exception for safety.
                   cmd = data.decode()
                   if cmd.startswith("stop"):
                       print(f"Stopping server")
                       is_active = False
                   else:
                       print(f"Unknown command: {cmd}")
               else:
                   # No more data, close connection
                   print(f"Closing connection {fd}")
                   select_fds.remove(conn)
                   conn.close()
                   conn = None
           elif fd in fds:
               print(f"Reading timer {fd}")
               count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder)
               print(f"Timer {fds.index(fd) + 1} expired {count} times")
           else:
               print(f"Unknown file descriptor {fd}")
finally:
    for fd in fds:
       os.close(fd)
    sock.close()
    sock = None

The Python 2.3 Method Resolution Order

참고

This is a historical document, provided as an appendix to the official documentation. The Method Resolution Order discussed here was introduced in Python 2.3, but it is still used in later versions – including Python 3.

By Michele Simionato [https://www.phyast.pitt.edu/~micheles/].

Abstract:

This document is intended for Python programmers who want to understand the C3 Method Resolution Order used in Python 2.3. Although it is not intended for newbies, it is quite pedagogical with many worked out examples. I am not aware of other publicly available documents with the same scope, therefore it should be useful.

Disclaimer:

I donate this document to the Python Software Foundation, under the Python 2.3 license. As usual in these circumstances, I warn the reader that what follows should be correct, but I don’t give any warranty. Use it at your own risk and peril!

Acknowledgments:

All the people of the Python mailing list who sent me their support. Paul Foley who pointed out various imprecisions and made me to add the part on local precedence ordering. David Goodger for help with the formatting in reStructuredText. David Mertz for help with the editing. Finally, Guido van Rossum who enthusiastically added this document to the official Python 2.3 home-page.

The beginning

Felix qui potuit rerum cognoscere causas – Virgilius

Everything started with a post by Samuele Pedroni to the Python development mailing list [1]. In his post, Samuele showed that the Python 2.2 method resolution order is not monotonic and he proposed to replace it with the C3 method resolution order. Guido agreed with his arguments and therefore now Python 2.3 uses C3. The C3 method itself has nothing to do with Python, since it was invented by people working on Dylan and it is described in a paper intended for lispers [2]. The present paper gives a (hopefully) readable discussion of the C3 algorithm for Pythonistas who want to understand the reasons for the change.

First of all, let me point out that what I am going to say only applies to the new style classes introduced in Python 2.2: classic classes maintain their old method resolution order, depth first and then left to right. Therefore, there is no breaking of old code for classic classes; and even if in principle there could be breaking of code for Python 2.2 new style classes, in practice the cases in which the C3 resolution order differs from the Python 2.2 method resolution order are so rare that no real breaking of code is expected. Therefore:

Don’t be scared!

Moreover, unless you make strong use of multiple inheritance and you have non-trivial hierarchies, you don’t need to understand the C3 algorithm, and you can easily skip this paper. On the other hand, if you really want to know how multiple inheritance works, then this paper is for you. The good news is that things are not as complicated as you might expect.

Let me begin with some basic definitions.

Given a class C in a complicated multiple inheritance hierarchy, it is a non-trivial task to specify the order in which methods are overridden, i.e. to specify the order of the ancestors of C.

The list of the ancestors of a class C, including the class itself, ordered from the nearest ancestor to the furthest, is called the class precedence list or the linearization of C.

The Method Resolution Order (MRO) is the set of rules that construct the linearization. In the Python literature, the idiom “the MRO of C” is also used as a synonymous for the linearization of the class C.

For instance, in the case of single inheritance hierarchy, if C is a subclass of C1, and C1 is a subclass of C2, then the linearization of C is simply the list [C, C1 , C2]. However, with multiple inheritance hierarchies, the construction of the linearization is more cumbersome, since it is more difficult to construct a linearization that respects local precedence ordering and monotonicity.

I will discuss the local precedence ordering later, but I can give the definition of monotonicity here. A MRO is monotonic when the following is true: if C1 precedes C2 in the linearization of C, then C1 precedes C2 in the linearization of any subclass of C. Otherwise, the innocuous operation of deriving a new class could change the resolution order of methods, potentially introducing very subtle bugs. Examples where this happens will be shown later.

Not all classes admit a linearization. There are cases, in complicated hierarchies, where it is not possible to derive a class such that its linearization respects all the desired properties.

Here I give an example of this situation. Consider the hierarchy

>>> O = object
>>> class X(O): pass
>>> class Y(O): pass
>>> class A(X,Y): pass
>>> class B(Y,X): pass

which can be represented with the following inheritance graph, where I have denoted with O the object class, which is the beginning of any hierarchy for new style classes:

 -----------
|           |
|    O      |
|  /   \    |
 - X    Y  /
   |  / | /
   | /  |/
   A    B
   \   /
     ?

In this case, it is not possible to derive a new class C from A and B, since X precedes Y in A, but Y precedes X in B, therefore the method resolution order would be ambiguous in C.

Python 2.3 raises an exception in this situation (TypeError: MRO conflict among bases Y, X) forbidding the naive programmer from creating ambiguous hierarchies. Python 2.2 instead does not raise an exception, but chooses an ad hoc ordering (CABXYO in this case).

The C3 Method Resolution Order

Let me introduce a few simple notations which will be useful for the following discussion. I will use the shortcut notation:

C1 C2 ... CN

to indicate the list of classes [C1, C2, … , CN].

The head of the list is its first element:

head = C1

whereas the tail is the rest of the list:

tail = C2 ... CN.

I shall also use the notation:

C + (C1 C2 ... CN) = C C1 C2 ... CN

to denote the sum of the lists [C] + [C1, C2, … ,CN].

Now I can explain how the MRO works in Python 2.3.

Consider a class C in a multiple inheritance hierarchy, with C inheriting from the base classes B1, B2, … , BN. We want to compute the linearization L[C] of the class C. The rule is the following:

the linearization of C is the sum of C plus the merge of the linearizations of the parents and the list of the parents.

In symbolic notation:

L[C(B1 ... BN)] = C + merge(L[B1] ... L[BN], B1 ... BN)

In particular, if C is the object class, which has no parents, the linearization is trivial:

L[object] = object.

However, in general one has to compute the merge according to the following prescription:

take the head of the first list, i.e L[B1][0]; if this head is not in the tail of any of the other lists, then add it to the linearization of C and remove it from the lists in the merge, otherwise look at the head of the next list and take it, if it is a good head. Then repeat the operation until all the class are removed or it is impossible to find good heads. In this case, it is impossible to construct the merge, Python 2.3 will refuse to create the class C and will raise an exception.

This prescription ensures that the merge operation preserves the ordering, if the ordering can be preserved. On the other hand, if the order cannot be preserved (as in the example of serious order disagreement discussed above) then the merge cannot be computed.

The computation of the merge is trivial if C has only one parent (single inheritance); in this case:

L[C(B)] = C + merge(L[B],B) = C + L[B]

However, in the case of multiple inheritance things are more cumbersome and I don’t expect you can understand the rule without a couple of examples ;-)

Examples

First example. Consider the following hierarchy:

>>> O = object
>>> class F(O): pass
>>> class E(O): pass
>>> class D(O): pass
>>> class C(D,F): pass
>>> class B(D,E): pass
>>> class A(B,C): pass

In this case the inheritance graph can be drawn as:

                          6
                         ---
Level 3                 | O |                  (more general)
                      /  ---  \
                     /    |    \                      |
                    /     |     \                     |
                   /      |      \                    |
                  ---    ---    ---                   |
Level 2        3 | D | 4| E |  | F | 5                |
                  ---    ---    ---                   |
                   \  \ _ /       |                   |
                    \    / \ _    |                   |
                     \  /      \  |                   |
                      ---      ---                    |
Level 1            1 | B |    | C | 2                 |
                      ---      ---                    |
                        \      /                      |
                         \    /                      \ /
                           ---
Level 0                 0 | A |                (more specialized)
                           ---

The linearizations of O,D,E and F are trivial:

L[O] = O
L[D] = D O
L[E] = E O
L[F] = F O

The linearization of B can be computed as:

L[B] = B + merge(DO, EO, DE)

We see that D is a good head, therefore we take it and we are reduced to compute merge(O,EO,E). Now O is not a good head, since it is in the tail of the sequence EO. In this case the rule says that we have to skip to the next sequence. Then we see that E is a good head; we take it and we are reduced to compute merge(O,O) which gives O. Therefore:

L[B] =  B D E O

Using the same procedure one finds:

L[C] = C + merge(DO,FO,DF)
     = C + D + merge(O,FO,F)
     = C + D + F + merge(O,O)
     = C D F O

Now we can compute:

L[A] = A + merge(BDEO,CDFO,BC)
     = A + B + merge(DEO,CDFO,C)
     = A + B + C + merge(DEO,DFO)
     = A + B + C + D + merge(EO,FO)
     = A + B + C + D + E + merge(O,FO)
     = A + B + C + D + E + F + merge(O,O)
     = A B C D E F O

In this example, the linearization is ordered in a pretty nice way according to the inheritance level, in the sense that lower levels (i.e. more specialized classes) have higher precedence (see the inheritance graph). However, this is not the general case.

I leave as an exercise for the reader to compute the linearization for my second example:

>>> O = object
>>> class F(O): pass
>>> class E(O): pass
>>> class D(O): pass
>>> class C(D,F): pass
>>> class B(E,D): pass
>>> class A(B,C): pass

The only difference with the previous example is the change B(D,E) –> B(E,D); however even such a little modification completely changes the ordering of the hierarchy:

                           6
                          ---
Level 3                  | O |
                       /  ---  \
                      /    |    \
                     /     |     \
                    /      |      \
                  ---     ---    ---
Level 2        2 | E | 4 | D |  | F | 5
                  ---     ---    ---
                   \      / \     /
                    \    /   \   /
                     \  /     \ /
                      ---     ---
Level 1            1 | B |   | C | 3
                      ---     ---
                       \       /
                        \     /
                          ---
Level 0                0 | A |
                          ---

Notice that the class E, which is in the second level of the hierarchy, precedes the class C, which is in the first level of the hierarchy, i.e. E is more specialized than C, even if it is in a higher level.

A lazy programmer can obtain the MRO directly from Python 2.2, since in this case it coincides with the Python 2.3 linearization. It is enough to invoke the mro() method of class A:

>>> A.mro()
[<class 'A'>, <class 'B'>, <class 'E'>,
<class 'C'>, <class 'D'>, <class 'F'>,
<class 'object'>]

Finally, let me consider the example discussed in the first section, involving a serious order disagreement. In this case, it is straightforward to compute the linearizations of O, X, Y, A and B:

L[O] = 0
L[X] = X O
L[Y] = Y O
L[A] = A X Y O
L[B] = B Y X O

However, it is impossible to compute the linearization for a class C that inherits from A and B:

L[C] = C + merge(AXYO, BYXO, AB)
     = C + A + merge(XYO, BYXO, B)
     = C + A + B + merge(XYO, YXO)

At this point we cannot merge the lists XYO and YXO, since X is in the tail of YXO whereas Y is in the tail of XYO: therefore there are no good heads and the C3 algorithm stops. Python 2.3 raises an error and refuses to create the class C.

Bad Method Resolution Orders

A MRO is bad when it breaks such fundamental properties as local precedence ordering and monotonicity. In this section, I will show that both the MRO for classic classes and the MRO for new style classes in Python 2.2 are bad.

It is easier to start with the local precedence ordering. Consider the following example:

>>> F=type('Food',(),{'remember2buy':'spam'})
>>> E=type('Eggs',(F,),{'remember2buy':'eggs'})
>>> G=type('GoodFood',(F,E),{}) # under Python 2.3 this is an error!

with inheritance diagram

             O
             |
(buy spam)   F
             | \
             | E   (buy eggs)
             | /
             G

      (buy eggs or spam ?)

We see that class G inherits from F and E, with F before E: therefore we would expect the attribute G.remember2buy to be inherited by F.rembermer2buy and not by E.remember2buy: nevertheless Python 2.2 gives

>>> G.remember2buy
'eggs'

This is a breaking of local precedence ordering since the order in the local precedence list, i.e. the list of the parents of G, is not preserved in the Python 2.2 linearization of G:

L[G,P22]= G E F object   # F *follows* E

One could argue that the reason why F follows E in the Python 2.2 linearization is that F is less specialized than E, since F is the superclass of E; nevertheless the breaking of local precedence ordering is quite non-intuitive and error prone. This is particularly true since it is a different from old style classes:

>>> class F: remember2buy='spam'
>>> class E(F): remember2buy='eggs'
>>> class G(F,E): pass
>>> G.remember2buy
'spam'

In this case the MRO is GFEF and the local precedence ordering is preserved.

As a general rule, hierarchies such as the previous one should be avoided, since it is unclear if F should override E or vice-versa. Python 2.3 solves the ambiguity by raising an exception in the creation of class G, effectively stopping the programmer from generating ambiguous hierarchies. The reason for that is that the C3 algorithm fails when the merge:

merge(FO,EFO,FE)

cannot be computed, because F is in the tail of EFO and E is in the tail of FE.

The real solution is to design a non-ambiguous hierarchy, i.e. to derive G from E and F (the more specific first) and not from F and E; in this case the MRO is GEF without any doubt.

           O
           |
           F (spam)
         / |
(eggs)   E |
         \ |
           G
             (eggs, no doubt)

Python 2.3 forces the programmer to write good hierarchies (or, at least, less error-prone ones).

On a related note, let me point out that the Python 2.3 algorithm is smart enough to recognize obvious mistakes, as the duplication of classes in the list of parents:

>>> class A(object): pass
>>> class C(A,A): pass # error
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: duplicate base class A

Python 2.2 (both for classic classes and new style classes) in this situation, would not raise any exception.

Finally, I would like to point out two lessons we have learned from this example:

despite the name, the MRO determines the resolution order of attributes, not only of methods;

the default food for Pythonistas is spam ! (but you already knew that ;-)

Having discussed the issue of local precedence ordering, let me now consider the issue of monotonicity. My goal is to show that neither the MRO for classic classes nor that for Python 2.2 new style classes is monotonic.

To prove that the MRO for classic classes is non-monotonic is rather trivial, it is enough to look at the diamond diagram:

   C
  / \
 /   \
A     B
 \   /
  \ /
   D

One easily discerns the inconsistency:

L[B,P21] = B C        # B precedes C : B's methods win
L[D,P21] = D A C B C  # B follows C  : C's methods win!

On the other hand, there are no problems with the Python 2.2 and 2.3 MROs, they give both:

L[D] = D A B C

Guido points out in his essay [3] that the classic MRO is not so bad in practice, since one can typically avoids diamonds for classic classes. But all new style classes inherit from object, therefore diamonds are unavoidable and inconsistencies shows up in every multiple inheritance graph.

The MRO of Python 2.2 makes breaking monotonicity difficult, but not impossible. The following example, originally provided by Samuele Pedroni, shows that the MRO of Python 2.2 is non-monotonic:

>>> class A(object): pass
>>> class B(object): pass
>>> class C(object): pass
>>> class D(object): pass
>>> class E(object): pass
>>> class K1(A,B,C): pass
>>> class K2(D,B,E): pass
>>> class K3(D,A):   pass
>>> class Z(K1,K2,K3): pass

Here are the linearizations according to the C3 MRO (the reader should verify these linearizations as an exercise and draw the inheritance diagram ;-)

L[A] = A O
L[B] = B O
L[C] = C O
L[D] = D O
L[E] = E O
L[K1]= K1 A B C O
L[K2]= K2 D B E O
L[K3]= K3 D A O
L[Z] = Z K1 K2 K3 D A B C E O

Python 2.2 gives exactly the same linearizations for A, B, C, D, E, K1, K2 and K3, but a different linearization for Z:

L[Z,P22] = Z K1 K3 A K2 D B C E O

It is clear that this linearization is wrong, since A comes before D whereas in the linearization of K3 A comes after D. In other words, in K3 methods derived by D override methods derived by A, but in Z, which still is a subclass of K3, methods derived by A override methods derived by D! This is a violation of monotonicity. Moreover, the Python 2.2 linearization of Z is also inconsistent with local precedence ordering, since the local precedence list of the class Z is [K1, K2, K3] (K2 precedes K3), whereas in the linearization of Z K2 follows K3. These problems explain why the 2.2 rule has been dismissed in favor of the C3 rule.

The end

This section is for the impatient reader, who skipped all the previous sections and jumped immediately to the end. This section is for the lazy programmer too, who didn’t want to exercise her/his brain. Finally, it is for the programmer with some hubris, otherwise s/he would not be reading a paper on the C3 method resolution order in multiple inheritance hierarchies ;-) These three virtues taken all together (and not separately) deserve a prize: the prize is a short Python 2.2 script that allows you to compute the 2.3 MRO without risk to your brain. Simply change the last line to play with the various examples I have discussed in this paper.:

#<mro.py>

"""C3 algorithm by Samuele Pedroni (with readability enhanced by me)."""

class __metaclass__(type):
    "All classes are metamagically modified to be nicely printed"
    __repr__ = lambda cls: cls.__name__

class ex_2:
    "Serious order disagreement" #From Guido
    class O: pass
    class X(O): pass
    class Y(O): pass
    class A(X,Y): pass
    class B(Y,X): pass
    try:
        class Z(A,B): pass #creates Z(A,B) in Python 2.2
    except TypeError:
        pass # Z(A,B) cannot be created in Python 2.3

class ex_5:
    "My first example"
    class O: pass
    class F(O): pass
    class E(O): pass
    class D(O): pass
    class C(D,F): pass
    class B(D,E): pass
    class A(B,C): pass

class ex_6:
    "My second example"
    class O: pass
    class F(O): pass
    class E(O): pass
    class D(O): pass
    class C(D,F): pass
    class B(E,D): pass
    class A(B,C): pass

class ex_9:
    "Difference between Python 2.2 MRO and C3" #From Samuele
    class O: pass
    class A(O): pass
    class B(O): pass
    class C(O): pass
    class D(O): pass
    class E(O): pass
    class K1(A,B,C): pass
    class K2(D,B,E): pass
    class K3(D,A): pass
    class Z(K1,K2,K3): pass

def merge(seqs):
    print '\n\nCPL[%s]=%s' % (seqs[0][0],seqs),
    res = []; i=0
    while 1:
      nonemptyseqs=[seq for seq in seqs if seq]
      if not nonemptyseqs: return res
      i+=1; print '\n',i,'round: candidates...',
      for seq in nonemptyseqs: # find merge candidates among seq heads
          cand = seq[0]; print ' ',cand,
          nothead=[s for s in nonemptyseqs if cand in s[1:]]
          if nothead: cand=None #reject candidate
          else: break
      if not cand: raise "Inconsistent hierarchy"
      res.append(cand)
      for seq in nonemptyseqs: # remove cand
          if seq[0] == cand: del seq[0]

def mro(C):
    "Compute the class precedence list (mro) according to C3"
    return merge([[C]]+map(mro,C.__bases__)+[list(C.__bases__)])

def print_mro(C):
    print '\nMRO[%s]=%s' % (C,mro(C))
    print '\nP22 MRO[%s]=%s' % (C,C.mro())

print_mro(ex_9.Z)

#</mro.py>

That’s all folks,

enjoy !

Resources

[1]

The thread on python-dev started by Samuele Pedroni: https://mail.python.org/pipermail/python-dev/2002-October/029035.html

[2]

The paper A Monotonic Superclass Linearization for Dylan: https://doi.org/10.1145/236337.236343

[3]

Guido van Rossum’s essay, Unifying types and classes in Python 2.2: https://web.archive.org/web/20140210194412/http://www.python.org/download/releases/2.2.2/descrintro

Python experimental support for free threading

Starting with the 3.13 release, CPython has experimental support for a build of Python called free threading where the global interpreter lock (GIL) is disabled. Free-threaded execution allows for full utilization of the available processing power by running threads in parallel on available CPU cores. While not all software will benefit from this automatically, programs designed with threading in mind will run faster on multi-core hardware.

The free-threaded mode is experimental and work is ongoing to improve it: expect some bugs and a substantial single-threaded performance hit.

This document describes the implications of free threading for Python code. See C API Extension Support for Free Threading for information on how to write C extensions that support the free-threaded build.

더 보기

PEP 703 [https://peps.python.org/pep-0703/] – Making the Global Interpreter Lock Optional in CPython for an overall description of free-threaded Python.

Installation

Starting with Python 3.13, the official macOS and Windows installers optionally support installing free-threaded Python binaries. The installers are available at https://www.python.org/downloads/.

For information on other platforms, see the Installing a Free-Threaded Python [https://py-free-threading.github.io/installing_cpython/], a community-maintained installation guide for installing free-threaded Python.

When building CPython from source, the --disable-gil configure option should be used to build a free-threaded Python interpreter.

Identifying free-threaded Python

To check if the current interpreter supports free-threading, python -VV and sys.version contain “experimental free-threading build”. The new sys._is_gil_enabled() function can be used to check whether the GIL is actually disabled in the running process.

The sysconfig.get_config_var("Py_GIL_DISABLED") configuration variable can be used to determine whether the build supports free threading. If the variable is set to 1, then the build supports free threading. This is the recommended mechanism for decisions related to the build configuration.

The global interpreter lock in free-threaded Python

Free-threaded builds of CPython support optionally running with the GIL enabled at runtime using the environment variable PYTHON_GIL or the command-line option -X gil.

The GIL may also automatically be enabled when importing a C-API extension module that is not explicitly marked as supporting free threading. A warning will be printed in this case.

In addition to individual package documentation, the following websites track the status of popular packages support for free threading:

https://py-free-threading.github.io/tracking/

https://hugovk.github.io/free-threaded-wheels/

Thread safety

The free-threaded build of CPython aims to provide similar thread-safety behavior at the Python level to the default GIL-enabled build. Built-in types like dict, list, and set use internal locks to protect against concurrent modifications in ways that behave similarly to the GIL. However, Python has not historically guaranteed specific behavior for concurrent modifications to these built-in types, so this should be treated as a description of the current implementation, not a guarantee of current or future behavior.

참고

It’s recommended to use the threading.Lock or other synchronization primitives instead of relying on the internal locks of built-in types, when possible.

Known limitations

This section describes known limitations of the free-threaded CPython build.

Immortalization

The free-threaded build of the 3.13 release makes some objects immortal. Immortal objects are not deallocated and have reference counts that are never modified. This is done to avoid reference count contention that would prevent efficient multi-threaded scaling.

An object will be made immortal when a new thread is started for the first time after the main thread is running. The following objects are immortalized:

function objects declared at the module level

method descriptors

code objects

module objects and their dictionaries

classes (type objects)

Because immortal objects are never deallocated, applications that create many objects of these types may see increased memory usage. This is expected to be addressed in the 3.14 release.

Additionally, numeric and string literals in the code as well as strings returned by sys.intern() are also immortalized. This behavior is expected to remain in the 3.14 free-threaded build.

Frame objects

It is not safe to access frame objects from other threads and doing so may cause your program to crash . This means that sys._current_frames() is generally not safe to use in a free-threaded build. Functions like inspect.currentframe() and sys._getframe() are generally safe as long as the resulting frame object is not passed to another thread.

Iterators

Sharing the same iterator object between multiple threads is generally not safe and threads may see duplicate or missing elements when iterating or crash the interpreter.

Single-threaded performance

The free-threaded build has additional overhead when executing Python code compared to the default GIL-enabled build. In 3.13, this overhead is about 40% on the pyperformance [https://pyperformance.readthedocs.io/] suite. Programs that spend most of their time in C extensions or I/O will see less of an impact. The largest impact is because the specializing adaptive interpreter (PEP 659 [https://peps.python.org/pep-0659/]) is disabled in the free-threaded build. We expect to re-enable it in a thread-safe way in the 3.14 release. This overhead is expected to be reduced in upcoming Python release. We are aiming for an overhead of 10% or less on the pyperformance suite compared to the default GIL-enabled build.

C API Extension Support for Free Threading

Starting with the 3.13 release, CPython has experimental support for running with the global interpreter lock (GIL) disabled in a configuration called free threading. This document describes how to adapt C API extensions to support free threading.

Identifying the Free-Threaded Build in C

The CPython C API exposes the Py_GIL_DISABLED macro: in the free-threaded build it’s defined to 1, and in the regular build it’s not defined. You can use it to enable code that only runs under the free-threaded build:

#ifdef Py_GIL_DISABLED
/* code that only runs in the free-threaded build */
#endif

Module Initialization

Extension modules need to explicitly indicate that they support running with the GIL disabled; otherwise importing the extension will raise a warning and enable the GIL at runtime.

There are two ways to indicate that an extension module supports running with the GIL disabled depending on whether the extension uses multi-phase or single-phase initialization.

Multi-Phase Initialization

Extensions that use multi-phase initialization (i.e., PyModuleDef_Init()) should add a Py_mod_gil slot in the module definition. If your extension supports older versions of CPython, you should guard the slot with a PY_VERSION_HEX check.

static struct PyModuleDef_Slot module_slots[] = {
    ...
#if PY_VERSION_HEX >= 0x030D0000
    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
#endif
    {0, NULL}
};

static struct PyModuleDef moduledef = {
    PyModuleDef_HEAD_INIT,
    .m_slots = module_slots,
    ...
};

Single-Phase Initialization

Extensions that use single-phase initialization (i.e., PyModule_Create()) should call PyUnstable_Module_SetGIL() to indicate that they support running with the GIL disabled. The function is only defined in the free-threaded build, so you should guard the call with #ifdef Py_GIL_DISABLED to avoid compilation errors in the regular build.

static struct PyModuleDef moduledef = {
    PyModuleDef_HEAD_INIT,
    ...
};

PyMODINIT_FUNC
PyInit_mymodule(void)
{
    PyObject *m = PyModule_Create(&moduledef);
    if (m == NULL) {
        return NULL;
    }
#ifdef Py_GIL_DISABLED
    PyUnstable_Module_SetGIL(m, Py_MOD_GIL_NOT_USED);
#endif
    return m;
}

General API Guidelines

Most of the C API is thread-safe, but there are some exceptions.

Struct Fields: Accessing fields in Python C API objects or structs directly is not thread-safe if the field may be concurrently modified.

Macros: Accessor macros like PyList_GET_ITEM and PyList_SET_ITEM do not perform any error checking or locking. These macros are not thread-safe if the container object may be modified concurrently.

Borrowed References: C API functions that return borrowed references may not be thread-safe if the containing object is modified concurrently. See the section on borrowed references for more information.

Container Thread Safety

Containers like PyListObject, PyDictObject, and PySetObject perform internal locking in the free-threaded build. For example, the PyList_Append() will lock the list before appending an item.

PyDict_Next

A notable exception is PyDict_Next(), which does not lock the dictionary. You should use Py_BEGIN_CRITICAL_SECTION to protect the dictionary while iterating over it if the dictionary may be concurrently modified:

Py_BEGIN_CRITICAL_SECTION(dict);
PyObject *key, *value;
Py_ssize_t pos = 0;
while (PyDict_Next(dict, &pos, &key, &value)) {
    ...
}
Py_END_CRITICAL_SECTION();

Borrowed References

Some C API functions return borrowed references. These APIs are not thread-safe if the containing object is modified concurrently. For example, it’s not safe to use PyList_GetItem() if the list may be modified concurrently.

The following table lists some borrowed reference APIs and their replacements that return strong references.

Borrowed reference API

Strong reference API

PyList_GetItem()

PyList_GetItemRef()

PyDict_GetItem()

PyDict_GetItemRef()

PyDict_GetItemWithError()

PyDict_GetItemRef()

PyDict_GetItemString()

PyDict_GetItemStringRef()

PyDict_SetDefault()

PyDict_SetDefaultRef()

PyDict_Next()

none (see PyDict_Next)

PyWeakref_GetObject()

PyWeakref_GetRef()

PyWeakref_GET_OBJECT()

PyWeakref_GetRef()

PyImport_AddModule()

PyImport_AddModuleRef()

Not all APIs that return borrowed references are problematic. For example, PyTuple_GetItem() is safe because tuples are immutable. Similarly, not all uses of the above APIs are problematic. For example, PyDict_GetItem() is often used for parsing keyword argument dictionaries in function calls; those keyword argument dictionaries are effectively private (not accessible by other threads), so using borrowed references in that context is safe.

Some of these functions were added in Python 3.13. You can use the pythoncapi-compat [https://github.com/python/pythoncapi-compat] package to provide implementations of these functions for older Python versions.

Memory Allocation APIs

Python’s memory management C API provides functions in three different allocation domains: “raw”, “mem”, and “object”. For thread-safety, the free-threaded build requires that only Python objects are allocated using the object domain, and that all Python object are allocated using that domain. This differs from the prior Python versions, where this was only a best practice and not a hard requirement.

참고

Search for uses of PyObject_Malloc() in your extension and check that the allocated memory is used for Python objects. Use PyMem_Malloc() to allocate buffers instead of PyObject_Malloc().

Thread State and GIL APIs

Python provides a set of functions and macros to manage thread state and the GIL, such as:

PyGILState_Ensure() and PyGILState_Release()

PyEval_SaveThread() and PyEval_RestoreThread()

Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS

These functions should still be used in the free-threaded build to manage thread state even when the GIL is disabled. For example, if you create a thread outside of Python, you must call PyGILState_Ensure() before calling into the Python API to ensure that the thread has a valid Python thread state.

You should continue to call PyEval_SaveThread() or Py_BEGIN_ALLOW_THREADS around blocking operations, such as I/O or lock acquisitions, to allow other threads to run the cyclic garbage collector.

Protecting Internal Extension State

Your extension may have internal state that was previously protected by the GIL. You may need to add locking to protect this state. The approach will depend on your extension, but some common patterns include:

Caches: global caches are a common source of shared state. Consider using a lock to protect the cache or disabling it in the free-threaded build if the cache is not critical for performance.

Global State: global state may need to be protected by a lock or moved to thread local storage. C11 and C++11 provide the thread_local or _Thread_local for thread-local storage [https://en.cppreference.com/w/c/language/storage_duration].

Building Extensions for the Free-Threaded Build

C API extensions need to be built specifically for the free-threaded build. The wheels, shared libraries, and binaries are indicated by a t suffix.

pypa/manylinux [https://github.com/pypa/manylinux] supports the free-threaded build, with the t suffix, such as python3.13t.

pypa/cibuildwheel [https://github.com/pypa/cibuildwheel] supports the free-threaded build if you set CIBW_FREE_THREADED_SUPPORT [https://cibuildwheel.pypa.io/en/stable/options/#free-threaded-support].

Limited C API and Stable ABI

The free-threaded build does not currently support the Limited C API or the stable ABI. If you use setuptools [https://setuptools.pypa.io/en/latest/setuptools.html] to build your extension and currently set py_limited_api=True you can use py_limited_api=not sysconfig.get_config_var("Py_GIL_DISABLED") to opt out of the limited API when building with the free-threaded build.

참고

You will need to build separate wheels specifically for the free-threaded build. If you currently use the stable ABI, you can continue to build a single wheel for multiple non-free-threaded Python versions.

Windows

Due to a limitation of the official Windows installer, you will need to manually define Py_GIL_DISABLED=1 when building extensions from source.

더 보기

Porting Extension Modules to Support Free-Threading [https://py-free-threading.github.io/porting/]: A community-maintained porting guide for extension authors.

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파이썬은 애초에 왜 만들어졌습니까?

파이썬의 강점은 무엇입니까?

파이썬 버전 관리 규칙은 무엇입니까?

파이썬 소스를 어떻게 얻을 수 있습니까?

파이썬 설명 문서는 어떻게 구합니까?

저는 프로그래밍을 해본 적이 없습니다. 파이썬 튜토리얼이 있습니까?

파이썬에 특화된 뉴스 그룹이나 메일링 리스트가 있습니까?

파이썬 베타 테스트 버전은 어떻게 구합니까?

파이썬 버그 리포트나 패치는 어떻게 제출합니까?

제가 참고할만한 파이썬 관련 기사가 있습니까?

파이썬 관련 책이 있습니까?

도대체 www.python.org는 어디에 있는 겁니까?

왜 이 언어는 파이썬이라 불립니까?

“몬티 파이튼의 플라잉 서커스”를 좋아해야합니까?

현실 속의 파이썬

파이썬은 어느 정도 안정화 되어있습니까?

얼마나 많은 사람이 파이썬을 씁니까?

파이썬으로 진행된 중요한 프로젝트가 존재합니까?

파이썬에 어떤 새로운 개발요소들이 예정되어 있습니까?

기존의 파이썬과 호환 가능하지 않은 변경안을 제시해도 괜찮습니까?

파이썬이 초보 프로그래머들에게 좋은 언어입니까?

일반적인 정보

파이썬이 무엇입니까?

파이썬은 인터프리터 방식의, 해석되고 상호작용이 가능한, 객체 지향적 프로그래밍 언어입니다. 모듈, 예외, 동적 타이핑, 굉장히 높은 수준의 동적 데이터 타입, 그리고 클래스를 내포하고 있습니다. 절차적이나 함수형 프로그래밍과 같은 객체 지향 프로그래밍 이외의 여러 프로그래밍 패러다임을 지원합니다. 파이썬은 굉장히 깔끔한 구문으로 놀랄만한 힘을 결합합니다. 이 언어는 다양한 시스템 호출과 라이브러리 뿐만 아니라 다양한 윈도우 시스템 관련 인터페이스를 갖고 있으며, C 언어와 C++ 언어로 확장이 가능합니다. 또한 프로그래밍 인터페이스가 필요한 애플리케이션의 확장 언어로도 사용할 수 있습니다. 마지막으로, 파이썬은 리눅스와 macOS를 포함하는 많은 유닉스 변종과 윈도우에서 돌아가는 포터블 언어입니다.

추가 정보는 파이썬 자습서에 있습니다. 파이썬 초보자 가이드 [https://wiki.python.org/moin/BeginnersGuide]에서 다른 기초 자습서와 파이썬을 배우기 위한 자료들을 볼 수 있습니다.

파이썬 소프트웨어 재단이 무엇입니까?

파이썬 소프트웨어 재단이란 파이썬 2.1과 그 윗 버전의 저작권을 소유하고 있는 독립적이고 비영리적인 단체입니다. 이 재단의 사명은 파이썬의 사용을 대중화 시키고 파이썬 관련 오픈소스 기술을 발전시키는 것입니다. 파이썬 소프트웨어 재단의 홈페이지: https://www.python.org/psf/.

파이썬 소프트웨어 재단으로의 기부는 미국에서 세액공제 적용 대상입니다. 파이썬을 사용하고 도움이 된다고 생각한다면 PSF 기부 페이지 [https://www.python.org/psf/donations/]를 통해 기여해 주십시오.

파이썬을 사용할 때 저작권 관련 제한이 있습니까?

본인이 생성한 파이썬에 대해 저작권을 명시하고, 이와 관련된 정보를 어떠한 형태로든 설명서에 표시하면 본인의 소스로 무엇이든 할 수 있습니다. 저작권 관련 규칙을 따르면 파이썬을 상업 목적으로 사용해도 괜찮으며, 소스코드나 (수정된 또는 수정되지 않은) 이진형태의 파이썬을 팔거나, 파이썬을 내장하는 상품을 팔아도 괜찮습니다. 그럼에도 저희는 파이썬이 사용된 모든 상업 활동을 알고 싶습니다.

See the license page [https://docs.python.org/3/license.html] to find further explanations and the full text of the PSF License.

파이썬 로고는 상표로 등록되어 있으며, 일부 경우에는 사용하기 위한 허가가 필요합니다. 더 많은 정보를 원하시면 상표 사용 정책 [https://www.python.org/psf/trademakrs/]을 참조하십시오.

파이썬은 애초에 왜 만들어졌습니까?

여기 Guido van Rossum 씨가 작성한 굉장히 요약된 파이썬의 탄생 계기입니다:

저는 CWI(Centrum Wiskunde & Informatica)의 ABC 그룹에서 인터프리터 언어를 도입하며 광범위한 경험을 해봤고, 그 그룹과 일하며 언어의 디자인에 대해 많은 것을 배웠습니다. 들여쓰기로 문단 묶기나 매우-상위-레벨 자료형을 포함한 것과 같은 파이썬의 다양한 기능들이 이 당시 경험을 바탕으로 만들어졌습니다.

ABC 언어에 있어서 저는 불만도 있었지만, 마음에 드는 기능도 많았습니다. ABC 언어(그리고 언어의 이행과정)는 제 불만을 극복할 만큼 확장할 방법이 없었죠. –사실 확장성이 떨어지는 것이 이 언어의 가장 큰 문제점 중 하나였습니다. 저는 Modula-2+를 사용하는데 약간의 경험이 있었고 Modula-3의 디자이너 분들과 대화도 나눠보았으며 Modula-3 관련 레포트도 읽어본 상태였습니다. Modula-3은 예외에서 쓰인 문법과 의미론을 비롯한 일부 파이썬 기능들의 기원입니다.

저는 CWI에서 Amoeba 분산 운영체제 그룹에 속해 일하고 있었습니다. Amoeba는 Bourne 셸로는 쉽게 접근하지 못하는 고유의 시스템 호출 인터페이스를 내장하고 있었기 때문에 저희는 C 프로그램이나 Bourne 셸 스크립트를 작성하는 것이 아닌 더 좋은 시스템 관리 방법이 필요했습니다. Amoeba에서 에러 처리를 해본 경험 덕분에 저는 프로그래밍 언어의 기능에 있어서 예외의 중요성을 인지하고 있었습니다.

ABC의 문법을 지키면서 Amoeba 시스템 호출에 접근 가능한 스크립트 언어가 필요하다는 것을 깨달았죠. Amoeba 특유의 언어를 만드는 건 어리석은 행동이라고 느껴서 대체로 확장 가능한 언어가 필요한 상황이라고 판단했습니다.

1989년 크리스마스 연휴에 저는 많은 시간이 있었고, 그 참에 도전해보기로 했습니다. 다음 해에도 제 개인적인 시간을 투자하며 언어를 완성시켜 가는 와중에 Python은 Amoeba 프로젝트에서 날이 갈수록 성공적으로 사용되고 있었습니다. 그리고 제 동료들의 피드백을 통해 저는 초기 개선사항들을 추가할 수 있었죠.

1991년 2월, 1년이 조금 넘는 개발 기간 후, 저는 USENET에 올리기로 했습니다. 나머지는 Misc/HSTORY 파일에 있습니다.

파이썬의 강점은 무엇입니까?

파이썬은 다양한 상황에 적용 가능한, 범용성 있는 고급언어입니다.

The language comes with a large standard library that covers areas such as string processing (regular expressions, Unicode, calculating differences between files), internet protocols (HTTP, FTP, SMTP, XML-RPC, POP, IMAP), software engineering (unit testing, logging, profiling, parsing Python code), and operating system interfaces (system calls, filesystems, TCP/IP sockets). Look at the table of contents for 파이썬 표준 라이브러리 to get an idea of what’s available. A wide variety of third-party extensions are also available. Consult the Python Package Index [https://pypi.org] to find packages of interest to you.

파이썬 버전 관리 규칙은 무엇입니까?

Python versions are numbered “A.B.C” or “A.B”:

A is the major version number – it is only incremented for really major changes in the language.

B is the minor version number – it is incremented for less earth-shattering changes.

C is the micro version number – it is incremented for each bugfix release.

Not all releases are bugfix releases. In the run-up to a new feature release, a series of development releases are made, denoted as alpha, beta, or release candidate. Alphas are early releases in which interfaces aren’t yet finalized; it’s not unexpected to see an interface change between two alpha releases. Betas are more stable, preserving existing interfaces but possibly adding new modules, and release candidates are frozen, making no changes except as needed to fix critical bugs.

Alpha, beta and release candidate versions have an additional suffix:

The suffix for an alpha version is “aN” for some small number N.

The suffix for a beta version is “bN” for some small number N.

The suffix for a release candidate version is “rcN” for some small number N.

In other words, all versions labeled 2.0aN precede the versions labeled 2.0bN, which precede versions labeled 2.0rcN, and those precede 2.0.

또한 “+” 접미사가 붙은 버전을 마주할 수도 있습니다. 예) “2.2+”. 이는 CPython 개발 저장소에서 바로 빌드된, 배포되지 않은 버전입니다. 실제는 이 버전의 최종 소규모 배포가 이루어질 때 다음 소규모 버전으로 증가하여 “a0” 버전이 됩니다. 예) “2.4a0”.

See the Developer’s Guide [https://devguide.python.org/developer-workflow/development-cycle/] for more information about the development cycle, and PEP 387 [https://peps.python.org/pep-0387/] to learn more about Python’s backward compatibility policy. See also the documentation for sys.version, sys.hexversion, and sys.version_info.

파이썬 소스를 어떻게 얻을 수 있습니까?

최신 파이썬 소스는 python.org 또는 https://www.python.org/downloads/ 에서 항상 구할 수 있고, 최신 개발 소스는 https://github.com/python/cpython/ 에서 구할 수 있습니다.

소스 배포판은 모든 C 언어 코드, 스핑크스 형식의 문서, 파이썬 라이브러리 모듈, 예제 프로그램들, 그리고 일부 유용한 무료 배포 소프트웨어를 포함합니다. 소스는 대부분의 유닉스 플랫폼에서 추가 설정 없이 컴파일되고 실행 가능합니다.

소스 코드를 받고 컴파일하는 부분에서 추가 정보를 원하시면 파이썬 개발자 가이드의 개요 [https://devguide.python.org/setup/]를 참고하십시오.

파이썬 설명 문서는 어떻게 구합니까?

현재 파이썬의 안정화 버전에 관련된 표준 문서는 https://docs.python.org/3/에서 확인할 수 있습니다. PDF, 텍스트 문서, 그리고 다운로드 가능한 HTML 버전들은 https://docs.python.org/3/download.html 에서 구할 수 있습니다.

The documentation is written in reStructuredText and processed by the Sphinx documentation tool [https://www.sphinx-doc.org/]. The reStructuredText source for the documentation is part of the Python source distribution.

저는 프로그래밍을 해본 적이 없습니다. 파이썬 튜토리얼이 있습니까?

다양한 튜토리얼과 책이 존재합니다. 표준 문서로는 파이썬 자습서가 있습니다.

초보자 가이드 [https://wiki.python.org/moin/BeginnersGuide]에서 튜토리얼 목록과 같은 초보 파이썬 개발자를 위한 정보를 확인하십시오.

파이썬에 특화된 뉴스 그룹이나 메일링 리스트가 있습니까?

뉴스 그룹은 comp.lang.python, 그리고 메일링 리스트는 python-list [https://mail.python.org/mailman/listinfo/python-list]에서 확인 할 수 있습니다. 뉴스 그룹과 메일링 리스트는 서로 연동되어 있어서 뉴스를 읽는다면 메일을 구독할 필요가 없습니다. comp.lang.python은 활발하고 하루에도 수백 개의 포스팅이 올라오기 때문에 Usenet 독자들은 이 매체를 통해 더 원활하게 소통할 수 있을 것입니다.

Announcements of new software releases and events can be found in comp.lang.python.announce, a low-traffic moderated list that receives about five postings per day. It’s available as the python-announce mailing list [https://mail.python.org/mailman3/lists/python-announce-list.python.org/].

https://www.python.org/community/lists/ 에서 다른 메일링 리스트와 뉴스 그룹에 대한 정보를 확인할 수 있습니다.

파이썬 베타 테스트 버전은 어떻게 구합니까?

알파와 베타 배포판은 https://www.python.org/downloads/ 에서 확인할 수 있습니다. 모든 배포는 comp.lang.python 과 comp.lang.python.announce 뉴스그룹, 그리고 파이썬 홈페이지 https://www.python.org/ 에서 공지됩니다. 뉴스의 RSS 피드가 제공됩니다.

Git을 통해 파이썬의 개발 버전을 사용할 수 있습니다. 파이썬 개발자 가이드 [https://devguide.python.org/]를 확인하십시오.

파이썬 버그 리포트나 패치는 어떻게 제출합니까?

To report a bug or submit a patch, use the issue tracker at https://github.com/python/cpython/issues.

파이썬이 어떻게 개발되는지 더 알고 싶으시다면 파이썬 개발자 가이드 [https://devguide.python.org/]를 참조하십시오.

제가 참고할만한 파이썬 관련 기사가 있습니까?

당신이 가장 좋아하는 파이썬 책을 인용하는 것이 제일 좋을 것 같습니다.

The very first article [https://ir.cwi.nl/pub/18204] about Python was written in 1991 and is now quite outdated.

Guido van Rossum and Jelke de Boer, “Interactively Testing Remote Servers Using the Python Programming Language”, CWI Quearterly, Volume 4, Issue 4 (December 1991), Amsterdam, pp 283–303.

파이썬 관련 책이 있습니까?

예, 많이 있고 현재 출판되는 책들도 있습니다. 리스트를 원한다면 https://wiki.python.org/moin/PythonBooks 에서 파이썬 위키를 확인하십시오.

아니면 온라인 서점에서 “파이썬”을 검색하고 몬티 파이썬 관련 항목을 필터링해도 괜찮습니다; 검색할 때 “파이썬”과 “언어”를 검색해도 좋습니다.

도대체 www.python.org는 어디에 있는 겁니까?

The Python project’s infrastructure is located all over the world and is managed by the Python Infrastructure Team. Details here [https://infra.psf.io].

왜 이 언어는 파이썬이라 불립니까?

Guido van Rossum 씨가 파이썬을 구현할 당시 그는 1970년대에 BBC에서 방영된 코미디 시리즈인 “몬티 파이튼의 플라잉 서커스” [https://ko.wikipedia.org/wiki/몬티_파이튼]대본을 읽고 있었습니다. 판 로쉼은 자신이 만든 언어가 짧고 독창적이면서도 약간 신비한 느낌의 이름이 필요하다고 생각했기에 언어를 파이썬이라고 부르기로 결정했습니다.

“몬티 파이튼의 플라잉 서커스”를 좋아해야합니까?

아니요, 하지만 도움은 됩니다. :)

현실 속의 파이썬

파이썬은 어느 정도 안정화 되어있습니까?

Very stable. New, stable releases have been coming out roughly every 6 to 18 months since 1991, and this seems likely to continue. As of version 3.9, Python will have a new feature release every 12 months (PEP 602 [https://peps.python.org/pep-0602/]).

The developers issue bugfix releases of older versions, so the stability of existing releases gradually improves. Bugfix releases, indicated by a third component of the version number (e.g. 3.5.3, 3.6.2), are managed for stability; only fixes for known problems are included in a bugfix release, and it’s guaranteed that interfaces will remain the same throughout a series of bugfix releases.

The latest stable releases can always be found on the Python download page [https://www.python.org/downloads/]. Python 3.x is the recommended version and supported by most widely used libraries. Python 2.x is not maintained anymore [https://peps.python.org/pep-0373/].

얼마나 많은 사람이 파이썬을 씁니까?

아마 수백만의 사용자가 있을 텐데, 정확한 수를 얻기는 힘듭니다.

파이썬은 무료로 다운로드받을 수 있기 때문에 판매액이 없습니다. 그리고 파이썬은 다양한 사이트에서, 다양한 리눅스 배포판과 패키지로 제공되므로 다운로드 통계치 역시 모든 것을 알려주지 못합니다.

활발하게 활동하는 comp.lang.python이라는 뉴스그룹이 있지만 모든 파이썬 유저들이 그곳에 글을 올리지 않으며 심지어 읽는 것도 아닙니다.

파이썬으로 진행된 중요한 프로젝트가 존재합니까?

https://www.python.org/about/success 에서 파이썬을 사용한 프로젝트를 확인할 수 있습니다. 과거 파이썬 회의들 [https://www.python.org/community/workshops/]을 통해 파이썬의 성장에 기여한 다양한 기업들과 단체들을 확인할 수 있습니다.

High-profile Python projects include the Mailman mailing list manager [https://www.list.org] and the Zope application server [https://www.zope.dev]. Several Linux distributions, most notably Red Hat [https://www.redhat.com], have written part or all of their installer and system administration software in Python. Companies that use Python internally include Google, Yahoo, and Lucasfilm Ltd.

파이썬에 어떤 새로운 개발요소들이 예정되어 있습니까?

See https://peps.python.org/ for the Python Enhancement Proposals (PEPs). PEPs are design documents describing a suggested new feature for Python, providing a concise technical specification and a rationale. Look for a PEP titled “Python X.Y Release Schedule”, where X.Y is a version that hasn’t been publicly released yet.

New development is discussed on the python-dev mailing list [https://mail.python.org/mailman3/lists/python-dev.python.org/].

기존의 파이썬과 호환 가능하지 않은 변경안을 제시해도 괜찮습니까?

일반적으로, 아니요. 현재 전 세계에 수 없이 많은 파이썬 코드들이 작성되어 있으며, 이미 존재하는 프로그램의 아주 작은 부분이라도 무효화한다면 그 변경안은 눈살을 찌푸리고 봐야합니다. 당신이 변환 프로그램을 제공한다고 해도 설명서를 전부 업데이트 해야하는 문제가 남아있습니다. 뿐만 아니라 수 많은 책들이 파이썬에 관련해서 쓰여져 있는데, 저희는 한 순간에 그 모든 책들을 무효화 시키고 싶지 않습니다.

만약 기능이 바뀌어야 한다면 점차적인 업그레이드 방안의 제시를 필요로 합니다. PEP 5 [https://peps.python.org/pep-0005/]에서 하위호환 불가능한 변경을 도입할 때 사용자의 불편함을 최소화 하는 절차를 확인할 수 있습니다.

파이썬이 초보 프로그래머들에게 좋은 언어입니까?

예.

파스칼, C, 또는 C++나 Java의 일부처럼 절차적이고 정적인 언어를 학생들의 첫 언어로 가르치는 것은 아직 흔한 교육 방식입니다. 하지만 그들이 파이썬을 첫 언어로 배우는 것이 더 이로울 수도 있습니다. 파이썬은 굉장히 간단하면서도 일관된 문법과 방대한 표준 라이브러리를 가지고 있으며, 무엇보다 초기 프로그래밍 교육에서 파이썬을 이용하면 학생들이 자료형 디자인, 그리고 문제 분석과 같은 중요한 프로그래밍 능력에 집중할 수 있도록 해줍니다. 학생들은 파이썬을 통해 반복문과 절차 같은 기초적인 콘셉트를 빠르게 접할 수 있습니다. 더 나아가 그들은 첫 강의에서 사용자 정의 객체를 활용하여 작업을 할 수도 있을 것입니다.

프로그래밍을 한 번도 해본 적이 없는 학생이라면 정적인 프로그래밍 언어를 사용하는 것은 자연스럽게 느껴지지 않을 것입니다. 그 과정을 해결하기 위해서는 부가적인 요소를 익혀야하며, 이는 강의 속도를 낮춥니다. 학생들은 컴퓨터처럼 사고하는 방식, 문제를 분석하는 방법, 일정한 인터페이스를 디자인하는 방법, 그리고 정보를 캡슐화하는 것을 배우려 합니다. 장기적으로 본다면 정적인 언어를 배우는 것이 중요할 수도 있지만, 학생들의 첫 프로그래밍 언어로 보았을 때는 좋다고 볼 수 없습니다.

파이썬이 첫 개발 언어로 좋은 이유로 다양한 요소들을 뽑습니다. 파이썬은 자바처럼 방대한 표준 라이브러리를 가지고 있어서 학생들이 수업의 극 초반에 뭔가 진짜 하는 프로그래밍 프로젝트를 경험할 수 있습니다. 네 개의 함수로 만들어보는 계산기나 가계부 프로그램이 과제의 전부가 아닙니다. 표준 라이브러리를 사용하므로써 학생들은 프로그래밍의 기본을 배우며 그럴싸한 애플리케이션을 만들어 볼 수 있습니다. 표준 라이브러리를 사용하면서 학생들에게 코드의 재활용 역시 가르쳐 줄 수 있습니다. 뿐만 아니라 PyGame 같은 제삼자 모듈 역시 학생들의 시야를 넓히는데 도움이 됩니다.

파이썬의 상호작용 가능한 인터프리터는 학생들이 코딩하며 언어의 기능을 테스트해 볼 수 있게 해줍니다. 학생들은 하나의 창에서 코드를 수정하며 다른 창에서 인터프리터를 돌려볼 수 있습니다. 만약 그들이 리스트에 대한 메서드가 기억나지 않는다면, 이와 같은 시도를 해볼 수 있습니다:

>>> L = []
>>> dir(L)
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
'__dir__', '__doc__', '__eq__', '__format__', '__ge__',
'__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__',
'__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__',
'__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__',
'__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__',
'__sizeof__', '__str__', '__subclasshook__', 'append', 'clear',
'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
'reverse', 'sort']
>>> [d for d in dir(L) if '__' not in d]
['append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

>>> help(L.append)
Help on built-in function append:

append(...)
    L.append(object) -> None -- append object to end

>>> L.append(1)
>>> L
[1]

인터프리터가 있다면, 학생들이 코딩하면서 설명서를 열람하기 쉽습니다.

There are also good IDEs for Python. IDLE is a cross-platform IDE for Python that is written in Python using Tkinter. Emacs users will be happy to know that there is a very good Python mode for Emacs. All of these programming environments provide syntax highlighting, auto-indenting, and access to the interactive interpreter while coding. Consult the Python wiki [https://wiki.python.org/moin/PythonEditors] for a full list of Python editing environments.

만약 파이썬이 교육 분야에서 어떻게 사용되는지에 대해 논의하고 싶으시면 the edu-sig mailing list [https://www.python.org/community/sigs/current/edu-sig]에 들어와 주십시오.

프로그래밍 FAQ

목차

프로그래밍 FAQ

일반적인 질문

중단점, 단일 스테핑(single-stepping) 등을 포함하는 소스 코드 수준 디버거가 있습니까?

버그를 찾거나 정적 분석을 수행하는 데 도움이 되는 도구가 있습니까?

파이썬 스크립트로 독립 실행형 바이너리를 만들려면 어떻게 해야 합니까?

파이썬 프로그램을 위한 코딩 표준이나 스타일 지침서가 있습니까?

핵심 언어

변수에 값이 있을 때 UnboundLocalError 가 발생하는 이유는 무엇입니까?

파이썬에서 지역과 전역 변수에 대한 규칙은 무엇입니까?

다른 값으로 루프에서 정의된 람다는 왜 모두 같은 결과를 반환합니까?

모듈 간에 전역 변수를 공유하려면 어떻게 해야 합니까?

모듈에서 임포트를 사용하는 “모범 사례”는 무엇입니까?

객체 간에 기본값이 공유되는 이유는 무엇입니까?

한 함수에서 다른 함수로 선택적이나 키워드 매개변수를 전달하려면 어떻게 해야 합니까?

인자와 매개변수의 차이점은 무엇입니까?

리스트 ‘y’를 변경할 때 리스트 ‘x’도 변경되는 이유는 무엇입니까?

출력 매개변수가 있는 함수를 작성하려면 어떻게 해야 합니까 (참조에 의한 호출)?

파이썬에서 고차 함수(higher order function)를 어떻게 만드나요?

파이썬에서 객체를 어떻게 복사합니까?

객체의 메서드나 어트리뷰트를 어떻게 찾을 수 있습니까?

코드에서 객체 이름을 어떻게 찾을 수 있습니까?

쉼표 연산자의 우선순위는 어떻게 되나요?

C의 “?:” 삼항 연산자와 동등한 것이 있습니까?

파이썬에서 난독화된 한 줄 코드를 작성할 수 있습니까?

함수의 매개변수 목록에서 슬래시(/)는 무엇을 의미합니까?

숫자와 문자열

16진수와 8진수 정수는 어떻게 지정합니까?

왜 -22 // 10 이 -3을 반환합니까?

How do I get int literal attribute instead of SyntaxError?

문자열을 숫자로 어떻게 변환합니까?

숫자를 문자열로 어떻게 변환합니까?

제자리에서 문자열을 어떻게 수정합니까?

문자열을 사용하여 어떻게 함수/메서드를 호출합니까?

문자열에서 후행 줄 바꿈을 제거하는 Perl의 chomp()와 동등한 것이 있습니까?

scanf()나 sscanf()에 해당하는 것이 있습니까?

‘UnicodeDecodeError’나 ‘UnicodeEncodeError’ 에러는 무엇을 의미합니까?

Can I end a raw string with an odd number of backslashes?

성능

내 프로그램이 너무 느립니다. 속도를 높이려면 어떻게 해야 합니까?

많은 문자열을 함께 이어붙이는 가장 효율적인 방법은 무엇입니까?

시퀀스 (튜플/리스트)

튜플과 리스트를 어떻게 변환합니까?

음수 인덱스는 무엇입니까?

시퀀스를 역순으로 이터레이트 하려면 어떻게 합니까?

리스트에서 중복을 어떻게 제거합니까?

리스트에서 여러 항목을 어떻게 제거합니까?

파이썬에서 어떻게 배열을 만드나요?

다차원 리스트를 어떻게 만듭니까?

How do I apply a method or function to a sequence of objects?

덧셈은 작동하는데, 왜 a_tuple[i] += [‘item’]이 예외를 일으킵니까?

복잡한 정렬을 하고 싶습니다: 파이썬에서 Schwartzian 변환을 할 수 있습니까?

한 리스트를 다른 리스트의 값으로 정렬하려면 어떻게 해야 합니까?

객체

클래스는 무엇입니까?

메서드는 무엇입니까?

self는 무엇입니까?

객체가 주어진 클래스나 그 서브 클래스의 인스턴스인지 어떻게 확인합니까?

위임이란 무엇입니까?

How do I call a method defined in a base class from a derived class that extends it?

베이스 클래스를 쉽게 변경할 수 있도록 코드를 구성하려면 어떻게 해야 합니까?

정적 클래스 데이터와 정적 클래스 메서드를 만들려면 어떻게 해야 합니까?

파이썬에서 생성자(또는 메서드)를 어떻게 재정의할 수 있습니까?

__spam을 사용하려고 하는데 _SomeClassName__spam에 대한 에러가 발생합니다.

내 클래스는 __del__을 정의하지만 객체를 삭제할 때 호출되지 않습니다.

주어진 클래스의 모든 인스턴스 목록을 어떻게 얻습니까?

id()의 결과가 고유하지 않은 것처럼 보이는 이유는 무엇입니까?

is 연산자를 사용한 아이덴티티 검사는 언제 신뢰할 수 있습니까?

How can a subclass control what data is stored in an immutable instance?

How do I cache method calls?

모듈

.pyc 파일을 어떻게 만듭니까?

현재 모듈 이름을 어떻게 찾습니까?

서로 임포트 하는 모듈을 어떻게 만들 수 있습니까?

__import__(‘x.y.z’)는 <module ‘x’>를 반환합니다; z를 어떻게 얻습니까?

임포트 된 모듈을 편집하고 다시 임포트 할 때, 변경 사항이 표시되지 않습니다. 왜 이런 일이 발생합니까?

일반적인 질문

중단점, 단일 스테핑(single-stepping) 등을 포함하는 소스 코드 수준 디버거가 있습니까?

예.

파이썬을 위한 여러 디버거가 아래에 설명되어 있으며, 내장 함수 breakpoint()를 사용하면 이들 중 하나로 들어갈 수 있습니다.

pdb 모듈은 간단하지만 적절한 파이썬 용 콘솔 모드 디버거입니다. 표준 파이썬 라이브러리의 일부이며, 라이브러리 레퍼런스 매뉴얼에서 설명하고 있습니다. pdb의 코드를 예로 사용하여 자체 디버거를 작성할 수도 있습니다.

The IDLE interactive development environment, which is part of the standard Python distribution (normally available as Tools/scripts/idle3 [https://github.com/python/cpython/blob/main/Tools/scripts/idle3]), includes a graphical debugger.

PythonWin is a Python IDE that includes a GUI debugger based on pdb. The PythonWin debugger colors breakpoints and has quite a few cool features such as debugging non-PythonWin programs. PythonWin is available as part of pywin32 [https://github.com/mhammond/pywin32] project and as a part of the ActivePython [https://www.activestate.com/products/python/] distribution.

Eric [https://eric-ide.python-projects.org/] is an IDE built on PyQt and the Scintilla editing component.

trepan3k [https://github.com/rocky/python3-trepan/] is a gdb-like debugger.

Visual Studio Code [https://code.visualstudio.com/] is an IDE with debugging tools that integrates with version-control software.

그래픽 디버거를 포함하는 많은 상용 파이썬 IDE가 있습니다. 다음을 포함합니다:

Wing IDE [https://wingware.com/]

Komodo IDE [https://www.activestate.com/products/komodo-ide/]

PyCharm [https://www.jetbrains.com/pycharm/]

버그를 찾거나 정적 분석을 수행하는 데 도움이 되는 도구가 있습니까?

예.

Pylint [https://pylint.pycqa.org/en/latest/index.html] and Pyflakes [https://github.com/PyCQA/pyflakes] do basic checking that will help you catch bugs sooner.

Static type checkers such as Mypy [https://mypy-lang.org/], Pyre [https://pyre-check.org/], and Pytype [https://github.com/google/pytype] can check type hints in Python source code.

파이썬 스크립트로 독립 실행형 바이너리를 만들려면 어떻게 해야 합니까?

사용자가 파이썬 배포를 먼저 설치하지 않고도 다운로드하여 실행할 수 있는 독립 실행형 프로그램을 원하는 것이 전부라면 파이썬을 C 코드로 컴파일하는 기능이 필요하지는 않습니다. 프로그램에 필요한 모듈 집합을 파악하고 이러한 모듈들을 파이썬 바이너리와 결합하여 단일 실행 파일을 생성하는 많은 도구가 있습니다.

One is to use the freeze tool, which is included in the Python source tree as Tools/freeze [https://github.com/python/cpython/tree/main/Tools/freeze]. It converts Python byte code to C arrays; with a C compiler you can embed all your modules into a new program, which is then linked with the standard Python modules.

소스를 재귀적으로 검색하여 import 문(두 형식 모두)을 찾고 표준 파이썬 경로뿐만 아니라 소스 디렉터리에서 모듈을 찾습니다 (내장할 모듈을 위해). 그런 다음 파이썬으로 작성된 모듈의 바이트 코드를 C 코드 (marshal 모듈을 사용하여 코드 객체로 변환할 수 있는 배열 초기화기)로 바꾸고 프로그램에서 실제로 사용되는 내장 모듈만 포함하는 특별한 구성 파일을 만듭니다. 그런 다음 생성된 C 코드를 컴파일하고 이를 나머지 파이썬 인터프리터와 링크하여 스크립트와 똑같게 작동하는 자체 포함 바이너리를 형성합니다.

The following packages can help with the creation of console and GUI executables:

Nuitka [https://nuitka.net/] (Cross-platform)

PyInstaller [https://pyinstaller.org/] (Cross-platform)

PyOxidizer [https://pyoxidizer.readthedocs.io/en/stable/] (Cross-platform)

cx_Freeze [https://marcelotduarte.github.io/cx_Freeze/] (Cross-platform)

py2app [https://github.com/ronaldoussoren/py2app] (macOS only)

py2exe [https://www.py2exe.org/] (Windows only)

파이썬 프로그램을 위한 코딩 표준이나 스타일 지침서가 있습니까?

예. 표준 라이브러리 모듈에 요구되는 코딩 스타일은 PEP 8 [https://peps.python.org/pep-0008/]에서 설명합니다.

핵심 언어

변수에 값이 있을 때 UnboundLocalError 가 발생하는 이유는 무엇입니까?

It can be a surprise to get the UnboundLocalError in previously working code when it is modified by adding an assignment statement somewhere in the body of a function.

이 코드는:

>>> x = 10
>>> def bar():
...     print(x)
...
>>> bar()
10

작동하지만, 이 코드는:

>>> x = 10
>>> def foo():
...     print(x)
...     x += 1

results in an UnboundLocalError:

>>> foo()
Traceback (most recent call last):
  ...
UnboundLocalError: local variable 'x' referenced before assignment

이는 스코프에서 변수에 대입할 때, 해당 변수가 그 스코프에 대해 지역(local)이 되고 외부 스코프에서 비슷한 이름의 변수를 가리기 때문입니다. foo의 마지막 문장은 x에 새 값을 대입하므로, 컴파일러는 이 값을 지역 변수로 인식합니다. 결과적으로 앞의 print(x)가 초기화되지 않은 지역 변수를 인쇄하려고 할 때 에러가 발생합니다.

위의 예에서 변수를 전역(global)으로 선언하여 외부 스코프 변수에 액세스 할 수 있습니다:

>>> x = 10
>>> def foobar():
...     global x
...     print(x)
...     x += 1
...
>>> foobar()
10

이 명시적 선언은 (클래스와 인스턴스 변수의 표면적으로 유사한 상황과 달리) 실제로 외부 스코프에 있는 변수의 값을 수정하고 있음을 상기시키기 위해 필요합니다:

>>> print(x)
11

nonlocal 키워드를 사용하여 중첩된 스코프에서 비슷한 일을 할 수 있습니다:

>>> def foo():
...    x = 10
...    def bar():
...        nonlocal x
...        print(x)
...        x += 1
...    bar()
...    print(x)
...
>>> foo()
10
11

파이썬에서 지역과 전역 변수에 대한 규칙은 무엇입니까?

파이썬에서, 함수 내에서 참조되기만 하는 변수는 묵시적으로 전역입니다. 변수가 함수 본문 내 어디에서건 값을 대입하면, 명시적으로 전역으로 선언되지 않는 한 지역으로 간주합니다.

처음에는 조금 의외지만, 잠시 생각해보면 이해가 됩니다. 한편으로, 대입된 변수에 global을 요구하면 의도하지 않은 부작용에 대한 저지선을 제공합니다. 반면에, 모든 전역 참조에 global이 요구된다면, 항상 global을 사용하게 됩니다. 내장 함수나 임포트 한 모듈의 구성 요소에 대한 모든 참조를 전역으로 선언해야 합니다. 이 혼란은 부작용을 식별하기 위한 global 선언의 유용성을 무효로 합니다.

다른 값으로 루프에서 정의된 람다는 왜 모두 같은 결과를 반환합니까?

for 루프를 사용하여 몇 가지 다른 람다(또는 일반 함수조차)를 정의한다고 가정하십시오, 예를 들어:

>>> squares = []
>>> for x in range(5):
...     squares.append(lambda: x**2)

이것은 x**2를 계산하는 5개의 람다가 포함된 리스트를 제공합니다. 호출되면, 각각 0, 1, 4, 9 및 16을 반환할 것으로 예상할 수 있습니다. 그러나, 실제로 시도하면 모두 16을 반환한다는 것을 알 수 있습니다:

>>> squares[2]()
16
>>> squares[4]()
16

이는 x가 람다에 지역(local)이 아니라 외부 스코프에 정의되어 있기 때문에 발생하며, 람다가 호출될 때 액세스 됩니다 — 정의될 때가 아닙니다. 루프의 끝에서, x의 값은 4이므로, 모든 함수는 이제 4**2, 즉 16을 반환합니다. x의 값을 변경하고 람다의 결과가 어떻게 변경되는지 봄으로써 이를 확인할 수도 있습니다:

>>> x = 8
>>> squares[2]()
64

이를 피하려면, 람다에 대해 지역인 변수에 값을 저장하여, 전역 x의 값에 의존하지 않도록 할 필요가 있습니다:

>>> squares = []
>>> for x in range(5):
...     squares.append(lambda n=x: n**2)

여기서 n=x는 람다에 지역인 새 변수 n을 만들고, 루프의 해당 시점에서 x 와 같은 값을 갖도록 람다가 정의될 때 계산됩니다. 이는 n의 값이 첫 번째 람다에서 0, 두 번째에서 1, 세 번째에서 2 등이 됨을 의미합니다. 따라서 각 람다는 이제 올바른 결과를 반환합니다:

>>> squares[2]()
4
>>> squares[4]()
16

이 동작은 람다에만 국한된 것이 아니라 일반 함수에도 적용됩니다.

모듈 간에 전역 변수를 공유하려면 어떻게 해야 합니까?

단일 프로그램 내에서 모듈 간에 정보를 공유하는 규범적인 방법은 특별한 모듈(종종 config나 cfg라고 불립니다)을 만드는 것입니다. 응용 프로그램의 모든 모듈에서 config 모듈을 임포트 하기만 하면 됩니다; 그러면 모듈이 전역 이름으로 사용 가능해집니다. 각 모듈의 인스턴스는 오직 하나이기 때문에, 모듈 객체에 대한 변경 사항은 모든 곳에 반영됩니다. 예를 들면 다음과 같습니다:

config.py:

x = 0   # Default value of the 'x' configuration setting

mod.py:

import config
config.x = 1

main.py:

import config
import mod
print(config.x)

Note that using a module is also the basis for implementing the singleton design pattern, for the same reason.

모듈에서 임포트를 사용하는 “모범 사례”는 무엇입니까?

일반적으로, from modulename import *를 사용하지 마십시오. 그렇게 하면 임포트 하는 곳의 이름 공간이 어수선해지고, 린터(linter)가 정의되지 않은 이름을 감지하기가 훨씬 어려워집니다.

파일 맨 위에서 모듈을 임포트 하십시오. 그렇게 하면 코드에 필요한 다른 모듈을 명확하게 하고 모듈 이름이 스코프에 있는지에 대한 질문을 피할 수 있습니다. 한 줄에 하나의 임포트를 사용하면 모듈 임포트를 쉽게 추가하고 삭제할 수 있지만, 한 줄에 여러 임포트를 사용하면 화면 공간을 덜 사용합니다.

다음 순서로 모듈을 임포트 하는 것이 좋습니다:

standard library modules – e.g. sys, os, argparse, re

third-party library modules (anything installed in Python’s site-packages directory) – e.g. dateutil, requests, PIL.Image

locally developed modules

순환 임포트 관련 문제를 피하고자 임포트를 함수나 클래스로 이동해야 하는 경우가 있습니다. Gordon McMillan은 다음과 같이 말했습니다:

두 모듈 모두 “import <module>” 형식의 임포트를 사용하면 순환 임포트는 괜찮습니다. 두 번째 모듈이 첫 번째 모듈의 이름(name)을 붙잡으려고 하고 (“from module import name”) 임포트가 최상위 수준에 있으면 실패합니다. 첫 번째 모듈이 두 번째 모듈을 임포트 하는 중이라서 첫 번째 모듈에 있는 이름을 아직 사용할 수 없기 때문입니다.

이 경우, 두 번째 모듈이 하나의 함수에서만 사용된다면, 임포트를 해당 함수로 쉽게 이동할 수 있습니다. 임포트가 호출될 때, 첫 번째 모듈의 초기화가 완료되었고, 두 번째 모듈은 임포트를 수행할 수 있습니다.

일부 모듈이 플랫폼 특정이면 임포트를 코드의 최상위 수준에서 다른 곳으로 이동해야 할 수도 있습니다. 이 경우, 파일 맨 위에서 모든 모듈을 임포트 하는 것이 가능하지 않을 수도 있습니다. 이 경우, 해당 플랫폼 특정 코드에서 올바른 모듈을 임포트 하는 것이 좋은 선택입니다.

순환 임포트를 피하거나 모듈의 초기화 시간을 줄이려는 등의 문제를 해결하는 데 필요할 때만, 함수 정의 내부와 같은 지역 스코프로 임포트를 옮기십시오. 이 기법은 프로그램 실행 방법에 따라 많은 임포트가 필요하지 않을 때 특히 유용합니다. 모듈이 해당 함수에서만 사용될 때 임포트를 함수로 옮기고 싶을 수도 있습니다. 모듈의 일회성 초기화 때문에 모듈을 처음 로드하는 데 비용이 많이들 수 있지만, 모듈을 여러 번 로드하는 것은 사실상 무료임에 유의하십시오, 두 번의 딕셔너리 조회만 발생합니다. 모듈 이름이 스코프를 벗어난 경우에도, 모듈은 아마도 sys.modules에 있을 겁니다.

객체 간에 기본값이 공유되는 이유는 무엇입니까?

이 유형의 버그는 흔히 신참 프로그래머들을 깨뭅니다. 이 함수를 생각해보십시오:

def foo(mydict={}):  # Danger: shared reference to one dict for all calls
    ... compute something ...
    mydict[key] = value
    return mydict

이 함수를 처음 호출하면, mydict에 단일 항목이 포함됩니다. 두 번째는, foo()가 실행되기 시작할 때, mydict가 이미 항목에 들어 있는 상태로 시작하기 때문에, mydict가 두 개의 항목을 포함합니다.

종종 함수 호출이 기본값으로 새 객체를 만들 것으로 기대합니다. 그렇게 되지 않습니다. 함수가 정의될 때, 기본값은 정확히 한 번 만들어집니다. 이 예제의 딕셔너리와 같이, 해당 객체가 변경되면, 함수에 대한 후속 호출은 이 변경된 객체를 참조합니다.

정의에 따라, 숫자, 문자열, 튜플 및 None과 같은 불변 객체는 변경에 안전합니다. 딕셔너리, 리스트 및 클래스 인스턴스와 같은 가변 객체를 변경하면 혼란스러울 수 있습니다.

이 기능으로 인해, 가변 객체를 기본값으로 사용하지 않는 것이 좋습니다. 대신, None을 기본값으로 사용하고 함수 내부에서 매개변수가 None인지 확인한 다음 새 리스트/딕셔너리/무엇이든 새로 만드십시오. 예를 들어, 다음과 같이 쓰지 마십시오:

def foo(mydict={}):
    ...

대신 이렇게 쓰십시오:

def foo(mydict=None):
    if mydict is None:
        mydict = {}  # create a new dict for local namespace

이 기능은 유용할 수 있습니다. 계산하는 데 시간이 걸리는 함수가 있을 때, 일반적인 기법은 각 함수 호출의 매개변수와 결괏값을 캐시하고, 같은 값이 다시 요청되면 캐시 된 값을 반환하는 것입니다. 이것을 “memoizing” 이라고 하며, 다음과 같이 구현할 수 있습니다:

# Callers can only provide two parameters and optionally pass _cache by keyword
def expensive(arg1, arg2, *, _cache={}):
    if (arg1, arg2) in _cache:
        return _cache[(arg1, arg2)]

    # Calculate the value
    result = ... expensive computation ...
    _cache[(arg1, arg2)] = result           # Store result in the cache
    return result

기본값 대신 딕셔너리를 포함하는 전역 변수를 사용할 수 있습니다; 취향의 문제입니다.

한 함수에서 다른 함수로 선택적이나 키워드 매개변수를 전달하려면 어떻게 해야 합니까?

함수의 매개변수 목록에 *와 ** 지정자를 사용하여 인자를 수집하십시오; 이것은 위치 인자를 튜플로, 키워드 인자를 딕셔너리로 제공합니다. 그런 다음 *와 **를 사용하여 다른 함수를 호출할 때 이러한 인자를 전달할 수 있습니다:

def f(x, *args, **kwargs):
    ...
    kwargs['width'] = '14.3c'
    ...
    g(x, *args, **kwargs)

인자와 매개변수의 차이점은 무엇입니까?

Parameters are defined by the names that appear in a function definition, whereas arguments are the values actually passed to a function when calling it. Parameters define what kind of arguments a function can accept. For example, given the function definition:

def func(foo, bar=None, **kwargs):
    pass

foo, bar 및 kwargs는 func의 매개변수입니다. 그러나, func를 호출할 때, 예를 들면:

func(42, bar=314, extra=somevar)

42, 314 및 somevar 값은 인자입니다.

리스트 ‘y’를 변경할 때 리스트 ‘x’도 변경되는 이유는 무엇입니까?

다음과 같은 코드를 작성하면:

>>> x = []
>>> y = x
>>> y.append(10)
>>> y
[10]
>>> x
[10]

y에 요소를 추가하면 x도 변경되는 이유가 궁금할 것입니다.

이 결과를 만드는 두 가지 요소가 있습니다:

변수는 단순히 객체를 가리키는 이름입니다. y = x를 수행하면 리스트의 사본을 만들지 않습니다 – x가 참조하는 것과 같은 객체를 참조하는 새 변수 y를 만듭니다. 이는 하나의 객체(리스트)만 있고, x 와 y 모두 그 객체를 참조함을 의미합니다.

리스트는 가변입니다, 내용을 변경할 수 있다는 뜻입니다.

After the call to append(), the content of the mutable object has changed from [] to [10]. Since both the variables refer to the same object, using either name accesses the modified value [10].

대신 불변 객체를 x에 대입하면:

>>> x = 5  # ints are immutable
>>> y = x
>>> x = x + 1  # 5 can't be mutated, we are creating a new object here
>>> x
6
>>> y
5

이 경우 x 와 y가 더는 같지 않다는 것을 알 수 있습니다. 이는 정수가 불변이기 때문이고, x = x + 1을 수행할 때 값을 증가시켜서 정수 5를 변경하는 것이 아닙니다; 대신 새 객체(정수 6)를 만들어 x에 대입합니다 (즉, x가 참조하는 객체를 바꿉니다). 이 대입 후에는 두 개의 객체(정수 6과 5)와 이를 참조하는 두 개의 변수를 갖게 됩니다 (x는 이제 6을 참조하지만, y는 여전히 5를 참조합니다).

Some operations (for example y.append(10) and y.sort()) mutate the object, whereas superficially similar operations (for example y = y + [10] and sorted(y)) create a new object. In general in Python (and in all cases in the standard library) a method that mutates an object will return None to help avoid getting the two types of operations confused. So if you mistakenly write y.sort() thinking it will give you a sorted copy of y, you’ll instead end up with None, which will likely cause your program to generate an easily diagnosed error.

그러나, 같은 연산이 때때로 형에 따라 다른 동작을 갖는 한 가지 연산 클래스가 있습니다: 증분 대입 연산자. 예를 들어, +=는 리스트를 변경하지만, 튜플이나 정수는 변경하지 않습니다 (a_list += [1, 2, 3]은 a_list.extend([1, 2, 3])과 동등하고 a_list를 변경하지만, some_tuple += (1, 2, 3)과 some_int += 1은 새 객체를 만듭니다).

달리 표현하면:

가변 객체(list, dict, set 등)가 있으면, 일부 특정 연산을 사용하여 객체를 변경하면 해당 객체를 참조하는 모든 변수가 변경을 보게 됩니다.

불변 객체(str, int, tuple 등)가 있으면, 이를 참조하는 모든 변수는 항상 같은 값을 보게 되지만, 해당 값을 새로운 값으로 변환하는 연산은 항상 새로운 객체를 반환합니다.

두 변수가 같은 객체를 참조하는지를 알고 싶다면, is 연산자나 내장 함수 id()를 사용할 수 있습니다.

출력 매개변수가 있는 함수를 작성하려면 어떻게 해야 합니까 (참조에 의한 호출)?

파이썬에서 인자는 대입으로 전달됨을 기억하십시오. 대입은 단지 객체에 대한 참조를 만들기 때문에, 호출자와 피호출자의 인자 이름 간에 에일리어스가 없고, 참조에 의한 호출도 없습니다. 여러 가지 방법으로 원하는 효과를 얻을 수 있습니다.

결과의 튜플을 반환하여:

>>> def func1(a, b):
...     a = 'new-value'        # a and b are local names
...     b = b + 1              # assigned to new objects
...     return a, b            # return new values
...
>>> x, y = 'old-value', 99
>>> func1(x, y)
('new-value', 100)

이것은 거의 항상 가장 명확한 해법입니다.

전역 변수를 사용하여. 이것은 스레드 안전하지 않고, 권장하지 않습니다.

가변 (제자리에서 변경할 수 있는) 객체를 전달하여:

>>> def func2(a):
...     a[0] = 'new-value'     # 'a' references a mutable list
...     a[1] = a[1] + 1        # changes a shared object
...
>>> args = ['old-value', 99]
>>> func2(args)
>>> args
['new-value', 100]

변경되는 딕셔너리를 전달하여:

>>> def func3(args):
...     args['a'] = 'new-value'     # args is a mutable dictionary
...     args['b'] = args['b'] + 1   # change it in-place
...
>>> args = {'a': 'old-value', 'b': 99}
>>> func3(args)
>>> args
{'a': 'new-value', 'b': 100}

또는 클래스 인스턴스에 값을 묶어서:

>>> class Namespace:
...     def __init__(self, /, **args):
...         for key, value in args.items():
...             setattr(self, key, value)
...
>>> def func4(args):
...     args.a = 'new-value'        # args is a mutable Namespace
...     args.b = args.b + 1         # change object in-place
...
>>> args = Namespace(a='old-value', b=99)
>>> func4(args)
>>> vars(args)
{'a': 'new-value', 'b': 100}

이렇게 복잡하게 만들어야 할 좋은 이유는 거의 없습니다.

최선의 선택은 여러 결과가 포함된 튜플을 반환하는 것입니다.

파이썬에서 고차 함수(higher order function)를 어떻게 만드나요?

두 가지 선택이 있습니다: 중첩된 스코프를 사용하거나 콜러블 객체를 사용할 수 있습니다. 예를 들어, 값 a*x+b를 계산하는 함수 f(x)를 반환하는 linear(a,b)를 정의하려고 한다고 가정하십시오. 중첩된 스코프를 사용해서:

def linear(a, b):
    def result(x):
        return a * x + b
    return result

또는 콜러블 객체를 사용해서:

class linear:

    def __init__(self, a, b):
        self.a, self.b = a, b

    def __call__(self, x):
        return self.a * x + self.b

두 경우 모두,

taxes = linear(0.3, 2)

taxes(10e6) == 0.3 * 10e6 + 2가 되도록 하는 콜러블 객체를 제공합니다.

콜러블 객체 접근 방식은 약간 느리고 코드가 약간 길어진다는 단점이 있습니다. 그러나, 콜러블 컬렉션은 상속을 통해 서명을 공유할 수 있습니다:

class exponential(linear):
    # __init__ inherited
    def __call__(self, x):
        return self.a * (x ** self.b)

객체는 여러 메서드의 상태를 캡슐화 할 수 있습니다:

class counter:

    value = 0

    def set(self, x):
        self.value = x

    def up(self):
        self.value = self.value + 1

    def down(self):
        self.value = self.value - 1

count = counter()
inc, dec, reset = count.up, count.down, count.set

여기서 inc(), dec() 및 reset()은 같은 계수 변수를 공유하는 함수처럼 작동합니다.

파이썬에서 객체를 어떻게 복사합니까?

일반적으로, 일반적일 때 copy.copy()나 copy.deepcopy()를 시도하십시오. 모든 객체를 복사할 수는 없지만, 대부분 가능합니다.

일부 객체는 더 쉽게 복사할 수 있습니다. 딕셔너리에는 copy() 메서드가 있습니다:

newdict = olddict.copy()

시퀀스는 슬라이싱으로 복사할 수 있습니다:

new_l = l[:]

객체의 메서드나 어트리뷰트를 어떻게 찾을 수 있습니까?

For an instance x of a user-defined class, dir(x) returns an alphabetized list of the names containing the instance attributes and methods and attributes defined by its class.

코드에서 객체 이름을 어떻게 찾을 수 있습니까?

일반적으로 말하자면, 객체에는 실제로 이름이 없기 때문에 그럴 수 없습니다. 기본적으로, 대입은 항상 이름을 값에 연결합니다; def와 class 문의 경우도 마찬가지이지만, 이 경우 값은 콜러블입니다. 다음 코드를 고려하십시오:

>>> class A:
...     pass
...
>>> B = A
>>> a = B()
>>> b = a
>>> print(b)
<__main__.A object at 0x16D07CC>
>>> print(a)
<__main__.A object at 0x16D07CC>

Arguably the class has a name: even though it is bound to two names and invoked through the name B the created instance is still reported as an instance of class A. However, it is impossible to say whether the instance’s name is a or b, since both names are bound to the same value.

일반적으로 말해 코드가 특정 값의 “이름을 알아야” 할 필요는 없습니다. 의도적으로 내성적인(introspective) 프로그램을 작성하지 않는 한, 이는 일반적으로 접근 방식의 변경이 도움이 될 수 있다는 신호입니다.

comp.lang.python에서, Fredrik Lundh는 언젠가 이 질문에 대해 훌륭한 비유를 했습니다:

여러분이 현관에서 발견한 고양이의 이름을 얻는 것과 같은 방법: 고양이(객체) 자체는 여러분에게 자신의 이름을 말할 수 없고, 전혀 신경 쓰지도 않습니다 – 따라서 그것이 어떻게 불리는지 알아내는 유일한 방법은 여러분 이웃 모두(이름 공간)에게 자신의 고양이(객체)인지 묻는 것입니다…

…. 여러 이름으로 알려져 있거나 전혀 이름이 없다는 것을 알게 되더라도 놀라지 마십시오!

쉼표 연산자의 우선순위는 어떻게 되나요?

쉼표는 파이썬에서 연산자가 아닙니다. 이 세션을 고려하십시오:

>>> "a" in "b", "a"
(False, 'a')

쉼표는 연산자가 아니라 표현식 사이의 구분자이기 때문에 위는 다음과 같이 입력한 것처럼 평가됩니다:

("a" in "b"), "a"

다음과 같이 평가되지 않습니다:

"a" in ("b", "a")

다양한 대입 연산자(=, += 등)도 마찬가지입니다. 이들은 실제로 연산자가 아니라 대입 문의 문법 구분자입니다.

C의 “?:” 삼항 연산자와 동등한 것이 있습니까?

예, 있습니다. 문법은 다음과 같습니다:

[on_true] if [expression] else [on_false]

x, y = 50, 25
small = x if x < y else y

이 문법이 파이썬 2.5에서 소개되기 전에, 일반적인 관용구는 논리 연산자를 사용하는 것이었습니다:

[expression] and [on_true] or [on_false]

그러나, 이 관용구는 안전하지 않습니다. on_true가 거짓 불리언 값을 가질 때 잘못된 결과가 나올 수 있습니다. 따라서, 항상 ... if ... else ... 형식을 사용하는 것이 좋습니다.

파이썬에서 난독화된 한 줄 코드를 작성할 수 있습니까?

Yes. Usually this is done by nesting lambda within lambda. See the following three examples, slightly adapted from Ulf Bartelt:

from functools import reduce

# Primes < 1000
print(list(filter(None,map(lambda y:y*reduce(lambda x,y:x*y!=0,
map(lambda x,y=y:y%x,range(2,int(pow(y,0.5)+1))),1),range(2,1000)))))

# First 10 Fibonacci numbers
print(list(map(lambda x,f=lambda x,f:(f(x-1,f)+f(x-2,f)) if x>1 else 1:
f(x,f), range(10))))

# Mandelbrot set
print((lambda Ru,Ro,Iu,Io,IM,Sx,Sy:reduce(lambda x,y:x+'\n'+y,map(lambda y,
Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,Sy=Sy,L=lambda yc,Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,i=IM,
Sx=Sx,Sy=Sy:reduce(lambda x,y:x+y,map(lambda x,xc=Ru,yc=yc,Ru=Ru,Ro=Ro,
i=i,Sx=Sx,F=lambda xc,yc,x,y,k,f=lambda xc,yc,x,y,k,f:(k<=0)or (x*x+y*y
>=4.0) or 1+f(xc,yc,x*x-y*y+xc,2.0*x*y+yc,k-1,f):f(xc,yc,x,y,k,f):chr(
64+F(Ru+x*(Ro-Ru)/Sx,yc,0,0,i)),range(Sx))):L(Iu+y*(Io-Iu)/Sy),range(Sy
))))(-2.1, 0.7, -1.2, 1.2, 30, 80, 24))
#    \___ ___/  \___ ___/  |   |   |__ lines on screen
#        V          V      |   |______ columns on screen
#        |          |      |__________ maximum of "iterations"
#        |          |_________________ range on y axis
#        |____________________________ range on x axis

집에서 이것을 시도하지 마십시오, 어린이들!

함수의 매개변수 목록에서 슬래시(/)는 무엇을 의미합니까?

A slash in the argument list of a function denotes that the parameters prior to it are positional-only. Positional-only parameters are the ones without an externally usable name. Upon calling a function that accepts positional-only parameters, arguments are mapped to parameters based solely on their position. For example, divmod() is a function that accepts positional-only parameters. Its documentation looks like this:

>>> help(divmod)
Help on built-in function divmod in module builtins:

divmod(x, y, /)
    Return the tuple (x//y, x%y).  Invariant: div*y + mod == x.

매개변수 목록 끝의 슬래시는 두 매개변수가 위치 전용임을 의미합니다. 따라서, 키워드 인자로 divmod()를 호출하면 에러가 발생합니다:

>>> divmod(x=3, y=4)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: divmod() takes no keyword arguments

숫자와 문자열

16진수와 8진수 정수는 어떻게 지정합니까?

8진수를 지정하려면, 8진수 값 앞에 0을 붙이고, 소문자나 대문자 “o”를 붙입니다. 예를 들어, 변수 “a”를 8진수 값 “10”(10진수 8)으로 설정하려면, 이렇게 입력하십시오:

>>> a = 0o10
>>> a
8

16진수도 쉽습니다. 16진수 앞에 0을 붙이고, 소문자나 대문자 “x”를 붙이기만 하면 됩니다. 16진 숫자는 소문자나 대문자로 지정할 수 있습니다. 예를 들어, 파이썬 인터프리터에서:

>>> a = 0xa5
>>> a
165
>>> b = 0XB2
>>> b
178

왜 -22 // 10 이 -3을 반환합니까?

주로 i % j가 j와 같은 부호를 갖도록 하려는 것입니다. 여러분이 이것을 원하고, 다음과 같은 것도 원한다면:

i == (i // j) * j + (i % j)

정수 나누기는 floor를 반환해야 합니다. C 또한 이 항등식을 만족하도록 요구하고, i // j를 자르는(truncate) 컴파일러는 i % j가 i 와 같은 부호를 갖도록 할 필요가 있습니다.

j가 음수인 경우 i % j에 대한 실제 사용 사례는 거의 없습니다. j가 양수이면, 많은 사례가 있으며, 사실상 모든 경우에 i % j가 >= 0인 것이 더 유용합니다. 시계가 지금 10을 가리킨다면, 200시간 전에는 어디를 가리키겠습니까? -190 % 12 == 2가 유용합니다; -190 % 12 == -10은 물기를 기다리는 버그입니다.

How do I get int literal attribute instead of SyntaxError?

Trying to lookup an int literal attribute in the normal manner gives a SyntaxError because the period is seen as a decimal point:

>>> 1.__class__
  File "<stdin>", line 1
  1.__class__
   ^
SyntaxError: invalid decimal literal

The solution is to separate the literal from the period with either a space or parentheses.

>>> 1 .__class__
<class 'int'>
>>> (1).__class__
<class 'int'>

문자열을 숫자로 어떻게 변환합니까?

For integers, use the built-in int() type constructor, e.g. int('144') == 144. Similarly, float() converts to a floating-point number, e.g. float('144') == 144.0.

기본적으로 이것은 숫자를 심진수로 해석합니다. 그래서 int('0144') == 144는 참이고 int('0x144')는 ValueError를 발생시킵니다. int(string, base)는 두 번째 선택적 인자로 변환에 사용할 진수(base)를 받아들여서, int( '0x144', 16) == 324입니다. base가 0으로 지정되면, 숫자는 파이썬의 규칙을 사용하여 해석됩니다: 선행 ‘0o’는 8진수를 나타내고, ‘0x’는 16진수를 나타냅니다.

필요한 것이 문자열을 숫자로 변환하는 것뿐이라면 내장 함수 eval()을 사용하지 마십시오. eval()은 상당히 느리며 보안 위험을 초래할 수 있습니다: 누군가 원하지 않는 부작용이 있는 파이썬 표현식을 전달할 수 있습니다. 예를 들어, 누군가 여러분의 홈 디렉터리를 지우는 __import__('os').system("rm -rf $HOME")을 전달할 수 있습니다.

eval()은 또한 숫자를 파이썬 표현식으로 해석하는 효과가 있어서, 예를 들어 eval('09')는 파이썬이 (‘0’을 제외한 )십진수에서 선행 ‘0’을 허용하지 않기 때문에 구문 에러가 발생합니다.

숫자를 문자열로 어떻게 변환합니까?

To convert, e.g., the number 144 to the string '144', use the built-in type constructor str(). If you want a hexadecimal or octal representation, use the built-in functions hex() or oct(). For fancy formatting, see the f-strings and 포맷 문자열 문법 sections, e.g. "{:04d}".format(144) yields '0144' and "{:.3f}".format(1.0/3.0) yields '0.333'.

제자리에서 문자열을 어떻게 수정합니까?

그럴 수 없습니다. 문자열은 불변이기 때문입니다. 대부분의 경우, 조립하려는 다양한 부분으로 새 문자열을 구성해야 합니다. 그러나 제자리에서 유니코드 데이터를 수정할 수 있는 객체가 필요하면, io.StringIO 객체나 array 모듈을 사용해보십시오:

>>> import io
>>> s = "Hello, world"
>>> sio = io.StringIO(s)
>>> sio.getvalue()
'Hello, world'
>>> sio.seek(7)
7
>>> sio.write("there!")
6
>>> sio.getvalue()
'Hello, there!'

>>> import array
>>> a = array.array('w', s)
>>> print(a)
array('w', 'Hello, world')
>>> a[0] = 'y'
>>> print(a)
array('w', 'yello, world')
>>> a.tounicode()
'yello, world'

문자열을 사용하여 어떻게 함수/메서드를 호출합니까?

다양한 기법이 있습니다.

문자열을 함수로 매핑하는 딕셔너리를 사용하는 것이 가장 좋습니다. 이 기법의 주요 장점은 문자열이 함수 이름과 일치할 필요가 없다는 것입니다. 이것은 또한 case 구문을 흉내 내는 데 사용되는 기본 기법입니다:

def a():
    pass

def b():
    pass

dispatch = {'go': a, 'stop': b}  # Note lack of parens for funcs

dispatch[get_input()]()  # Note trailing parens to call function

내장 함수 getattr()을 사용하십시오:

import foo
getattr(foo, 'bar')()

getattr()은 클래스, 클래스 인스턴스, 모듈 등을 포함하는 모든 객체에서 작동함에 유의하십시오.

이것은 다음과 같이 표준 라이브러리의 여러 곳에서 사용됩니다:

class Foo:
    def do_foo(self):
        ...

    def do_bar(self):
        ...

f = getattr(foo_instance, 'do_' + opname)
f()

함수 이름을 해석(resolve)하려면 locals()를 사용하십시오:

def myFunc():
    print("hello")

fname = "myFunc"

f = locals()[fname]
f()

문자열에서 후행 줄 바꿈을 제거하는 Perl의 chomp()와 동등한 것이 있습니까?

S.rstrip("\r\n")을 사용하면 다른 후행 공백을 제거하지 않고 문자열 S의 끝에 있는 모든 줄 종결자를 제거 할 수 있습니다. 문자열 S가 끝에 빈 줄이 여러 개 붙어 한 줄 이상을 나타내면, 모든 빈 줄의 줄 종결자가 제거됩니다:

>>> lines = ("line 1 \r\n"
...          "\r\n"
...          "\r\n")
>>> lines.rstrip("\n\r")
'line 1 '

일반적으로 한 번에 한 줄씩 텍스트를 읽을 때만 필요하기 때문에, S.rstrip()을 이런 식으로 사용하면 잘 작동합니다.

scanf()나 sscanf()에 해당하는 것이 있습니까?

그런 식으로는 없습니다.

For simple input parsing, the easiest approach is usually to split the line into whitespace-delimited words using the split() method of string objects and then convert decimal strings to numeric values using int() or float(). split() supports an optional “sep” parameter which is useful if the line uses something other than whitespace as a separator.

For more complicated input parsing, regular expressions are more powerful than C’s sscanf and better suited for the task.

‘UnicodeDecodeError’나 ‘UnicodeEncodeError’ 에러는 무엇을 의미합니까?

유니코드 HOWTO를 참조하십시오.

Can I end a raw string with an odd number of backslashes?

A raw string ending with an odd number of backslashes will escape the string’s quote:

>>> r'C:\this\will\not\work\'
  File "<stdin>", line 1
    r'C:\this\will\not\work\'
         ^
SyntaxError: unterminated string literal (detected at line 1)

There are several workarounds for this. One is to use regular strings and double the backslashes:

>>> 'C:\\this\\will\\work\\'
'C:\\this\\will\\work\\'

Another is to concatenate a regular string containing an escaped backslash to the raw string:

>>> r'C:\this\will\work' '\\'
'C:\\this\\will\\work\\'

It is also possible to use os.path.join() to append a backslash on Windows:

>>> os.path.join(r'C:\this\will\work', '')
'C:\\this\\will\\work\\'

Note that while a backslash will “escape” a quote for the purposes of determining where the raw string ends, no escaping occurs when interpreting the value of the raw string. That is, the backslash remains present in the value of the raw string:

>>> r'backslash\'preserved'
"backslash\\'preserved"

Also see the specification in the language reference.

성능

내 프로그램이 너무 느립니다. 속도를 높이려면 어떻게 해야 합니까?

그것은 일반적으로 힘든 일입니다. 먼저, 더 뛰어들기 전에 기억해야 할 사항이 있습니다:

성능 특성은 파이썬 구현마다 다릅니다. 이 FAQ는 CPython에 중점을 둡니다.

동작은 운영 체제마다 다를 수 있습니다, 특히 I/O 나 다중 스레드에 관해 이야기할 때 그렇습니다.

코드를 최적화하려고 시도하기 전에 프로그램에서 항상 핫스팟을 찾아야 합니다 (profile 모듈을 참조하십시오).

벤치마크 스크립트를 작성하면 개선 사항을 탐색할 때 빠르게 반복할 수 있습니다 (timeit 모듈 참조).

정교한 최적화에 숨겨진 회귀(regressions)를 잠재적으로 도입하기 전에 (단위 테스트나 기타 기법을 통해) 우수한 코드 커버리지를 갖는 것이 좋습니다.

이것을 전제로, 파이썬 코드 속도를 높이는 많은 트릭이 있습니다. 다음은 수용 가능한 성능 수준에 도달하기 위해 먼 길을 갈 때 도움이 되는 몇 가지 일반적인 원칙입니다:

알고리즘을 더 빠르게 만들면 (또는 더 빠른 알고리즘으로 변경하면) 코드 전체에 미세 최적화 트릭을 뿌리는 것보다 훨씬 큰 이점을 얻을 수 있습니다.

올바른 데이터 구조를 사용하십시오. 내장형과 collections 모듈에 대한 설명서를 연구하십시오.

표준 라이브러리가 무언가를 하기 위한 프리미티브를 제공할 때, 여러분이 떠올린 다른 대안보다 빠를 가능성이 높습니다 (보장되지는 않습니다). 이것은 내장과 일부 확장형과 같이 C로 작성된 프리미티브의 경우에는 두 배로 그렇습니다. 예를 들어, 정렬하려면 list.sort() 내장 메서드나 관련 sorted() 함수를 사용하십시오 (그리고 약간 고급 사용법의 예는 Sorting Techniques를 참조하십시오).

추상화는 간접(indirections)을 만드는 경향이 있고 인터프리터가 더 많은 일을 하도록 강요합니다. 간접의 수준이 유용한 작업의 양을 초과하면, 프로그램 속도가 느려집니다. 과도한 추상화를 피해야 합니다, 특히 작은 함수나 메서드의 형태에서 그렇습니다 (종종 가독성에도 해롭습니다).

If you have reached the limit of what pure Python can allow, there are tools to take you further away. For example, Cython [https://cython.org] can compile a slightly modified version of Python code into a C extension, and can be used on many different platforms. Cython can take advantage of compilation (and optional type annotations) to make your code significantly faster than when interpreted. If you are confident in your C programming skills, you can also write a C extension module yourself.

더 보기

성능 팁 [https://wiki.python.org/moin/PythonSpeed/PerformanceTips]에 할당된 위키 페이지.

많은 문자열을 함께 이어붙이는 가장 효율적인 방법은 무엇입니까?

str과 bytes 객체는 불변이므로, 많은 문자열을 함께 이어붙이면 각 이어붙이기가 새 객체를 생성하기 때문에 비효율적입니다. 일반적일 때, 총 실행 시간 비용은 전체 문자열 길이의 제곱에 비례합니다.

많은 str 객체를 누적하기 위해, 권장되는 관용구는 객체를 리스트에 배치하고 마지막에 str.join()을 호출하는 것입니다:

chunks = []
for s in my_strings:
    chunks.append(s)
result = ''.join(chunks)

(또 다른 합리적으로 효율적인 관용구는 io.StringIO를 사용하는 것입니다)

많은 bytes 객체를 누적하기 위해, 권장되는 관용구는 제자리 이어붙이기(+= 연산자)을 사용하여 bytearray 객체를 확장하는 것입니다:

result = bytearray()
for b in my_bytes_objects:
    result += b

시퀀스 (튜플/리스트)

튜플과 리스트를 어떻게 변환합니까?

형 생성자 tuple(seq)는 임의의 시퀀스(실제로는, 모든 이터러블)를 같은 순서로 같은 항목을 가진 튜플로 변환합니다.

예를 들어, tuple([1, 2, 3])은 (1, 2, 3)을 산출하고 tuple('abc')는 ('a', 'b', 'c')를 산출합니다. 인자가 튜플이면 사본을 만들지 않고 같은 객체를 반환하므로, 객체가 이미 튜플인지 확실하지 않을 때 tuple()을 호출하는 것이 저렴합니다.

형 생성자 list(seq)는 임의의 시퀀스나 이터러블을 같은 순서로 같은 항목이 있는 리스트로 변환합니다. 예를 들어, list((1, 2, 3))은 [1, 2, 3]을 산출하고 list('abc')는 ['a', 'b', 'c']를 산출합니다. 인자가 리스트이면, seq[:]와 같이 사본을 만듭니다.

음수 인덱스는 무엇입니까?

파이썬 시퀀스는 양수와 음수로 인덱싱됩니다. 양수의 경우 0은 첫 번째 인덱스이고 1은 두 번째 인덱스이고 이런 식으로 계속됩니다. 음수 인덱스의 경우 -1은 마지막 인덱스이고 -2는 끝에서 두 번째 인덱스이고 이런 식으로 계속됩니다. seq[-n]을 seq[len(seq)-n]과 같다고 생각하십시오.

음수 인덱스를 사용하면 매우 편리할 수 있습니다. 예를 들어 S[:-1]은 마지막 문자를 제외한 문자열의 모든 것인데, 문자열에서 후행 줄 바꿈을 제거하는 데 유용합니다.

시퀀스를 역순으로 이터레이트 하려면 어떻게 합니까?

reversed() 내장 함수를 사용하십시오:

for x in reversed(sequence):
    ...  # do something with x ...

이것은 원본 시퀀스에는 영향을 미치지 않지만, 이터레이트 할 뒤집힌 순서의 새 사본을 만듭니다.

리스트에서 중복을 어떻게 제거합니까?

이 작업을 수행하는 여러 가지 방법에 대한 긴 논의는 파이썬 요리책을 참조하십시오:

https://code.activestate.com/recipes/52560/

리스트 순서를 바꿔도 상관없다면, 리스트를 정렬한 다음 리스트 끝에서 스캔하면서 중복 항목을 삭제하십시오:

if mylist:
    mylist.sort()
    last = mylist[-1]
    for i in range(len(mylist)-2, -1, -1):
        if last == mylist[i]:
            del mylist[i]
        else:
            last = mylist[i]

리스트의 모든 요소가 집합 키로 사용될 수 있다면 (즉, 모두 해시 가능이면) 이것이 종종 더 빠릅니다

mylist = list(set(mylist))

이것은 리스트를 집합으로 변환하여, 중복을 제거한 다음, 리스트로 되돌립니다.

리스트에서 여러 항목을 어떻게 제거합니까?

중복 제거와 마찬가지로, 삭제 조건을 사용하여 명시적으로 역순으로 이터레이션 하는 것도 한 가지 가능성입니다. 그러나, 묵시적이나 명시적 순방향 이터레이션으로 슬라이스 치환을 사용하기가 더 쉽고 빠릅니다. 다음은 세 가지 변형입니다.:

mylist[:] = filter(keep_function, mylist)
mylist[:] = (x for x in mylist if keep_condition)
mylist[:] = [x for x in mylist if keep_condition]

리스트 컴프리헨션이 아마 가장 빠릅니다.

파이썬에서 어떻게 배열을 만드나요?

리스트를 사용하십시오:

["this", 1, "is", "an", "array"]

리스트는 시간 복잡성 면에서 C나 파스칼(Pascal) 배열과 동등합니다; 가장 큰 차이점은 파이썬 리스트에 다양한 형의 객체가 포함될 수 있다는 것입니다.

The array module also provides methods for creating arrays of fixed types with compact representations, but they are slower to index than lists. Also note that NumPy [https://numpy.org/] and other third party packages define array-like structures with various characteristics as well.

To get Lisp-style linked lists, you can emulate cons cells using tuples:

lisp_list = ("like",  ("this",  ("example", None) ) )

If mutability is desired, you could use lists instead of tuples. Here the analogue of a Lisp car is lisp_list[0] and the analogue of cdr is lisp_list[1]. Only do this if you’re sure you really need to, because it’s usually a lot slower than using Python lists.

다차원 리스트를 어떻게 만듭니까?

다음과 같이 다차원 배열을 만들려고 했을 것입니다:

>>> A = [[None] * 2] * 3

인쇄하면 올바르게 보입니다:

>>> A
[[None, None], [None, None], [None, None]]

그러나 값을 대입하면, 여러 위치에 나타납니다:

>>> A[0][0] = 5
>>> A
[[5, None], [5, None], [5, None]]

그 이유는 *로 리스트를 복제해도 복사본을 만들지 않고 기존 객체에 대한 참조만 만들기 때문입니다. *3은 길이 2의 같은 리스트에 대한 3개의 참조를 포함하는 리스트를 만듭니다. 한 행에 대한 변경 사항은 모든 행에 나타나는데, 거의 확실히 여러분이 원하는 것은 아닙니다.

제안된 방법은 원하는 길이의 리스트를 먼저 만든 다음 새로 만든 리스트로 각 요소를 채우는 것입니다:

A = [None] * 3
for i in range(3):
    A[i] = [None] * 2

그러면 길이가 2인 3개의 다른 리스트를 포함하는 리스트가 생성됩니다. 리스트 컴프리헨션도 사용할 수 있습니다:

w, h = 2, 3
A = [[None] * w for i in range(h)]

Or, you can use an extension that provides a matrix datatype; NumPy [https://numpy.org/] is the best known.

How do I apply a method or function to a sequence of objects?

To call a method or function and accumulate the return values is a list, a list comprehension is an elegant solution:

result = [obj.method() for obj in mylist]

result = [function(obj) for obj in mylist]

To just run the method or function without saving the return values, a plain for loop will suffice:

for obj in mylist:
    obj.method()

for obj in mylist:
    function(obj)

덧셈은 작동하는데, 왜 a_tuple[i] += [‘item’]이 예외를 일으킵니까?

이는 증분 대입 연산자가 대입 연산자라는 사실과 파이썬에서 가변 객체와 불변 객체의 차이점이 결합하기 때문입니다.

이 논의는 증분 대입 연산자가 가변 객체를 가리키는 튜플의 요소에 적용될 때 일반적으로 적용되지만, 우리는 list와 +=를 예제로 사용합니다.

다음과 같이 작성한다면:

>>> a_tuple = (1, 2)
>>> a_tuple[0] += 1
Traceback (most recent call last):
   ...
TypeError: 'tuple' object does not support item assignment

예외의 이유는 명확합니다: 1이 a_tuple[0]이 가리키는 객체(1)에 더해져서, 결과 객체 2를 생성하지만, 계산 결과 2를 튜플의 요소 0에 대입하려고 하면, 튜플의 요소가 가리키는 것을 변경할 수 없기 때문에 에러가 발생합니다.

수면 아래에서, 이 증분 대입문이 하는 일은 대략 다음과 같습니다:

>>> result = a_tuple[0] + 1
>>> a_tuple[0] = result
Traceback (most recent call last):
  ...
TypeError: 'tuple' object does not support item assignment

튜플은 불변이므로, 연산의 대입 부분이 에러를 발생시킵니다.

다음과 같이 작성하면:

>>> a_tuple = (['foo'], 'bar')
>>> a_tuple[0] += ['item']
Traceback (most recent call last):
  ...
TypeError: 'tuple' object does not support item assignment

예외는 조금 더 놀랍습니다, 더 놀라운 것은 에러가 있었지만 더하기가 동작했다는 사실입니다:

>>> a_tuple[0]
['foo', 'item']

To see why this happens, you need to know that (a) if an object implements an __iadd__() magic method, it gets called when the += augmented assignment is executed, and its return value is what gets used in the assignment statement; and (b) for lists, __iadd__() is equivalent to calling extend() on the list and returning the list. That’s why we say that for lists, += is a “shorthand” for list.extend():

>>> a_list = []
>>> a_list += [1]
>>> a_list
[1]

이것은 다음과 동등합니다:

>>> result = a_list.__iadd__([1])
>>> a_list = result

a_list가 가리키는 객체가 변경되었고, 변경된 객체에 대한 포인터가 다시 a_list에 대입됩니다. 대입의 최종 결과는 no-op인데, a_list가 이전에 가리키고 있던 것과 같은 객체에 대한 포인터이기 때문입니다, 하지만 대입은 여전히 일어납니다.

따라서, 우리의 튜플 예제에서 일어나는 일은 다음과 동등합니다:

>>> result = a_tuple[0].__iadd__(['item'])
>>> a_tuple[0] = result
Traceback (most recent call last):
  ...
TypeError: 'tuple' object does not support item assignment

The __iadd__() succeeds, and thus the list is extended, but even though result points to the same object that a_tuple[0] already points to, that final assignment still results in an error, because tuples are immutable.

복잡한 정렬을 하고 싶습니다: 파이썬에서 Schwartzian 변환을 할 수 있습니까?

Perl 커뮤니티의 Randal Schwartz에 의한 이 기법은 리스트의 각 요소를 각 요소를 “정렬 값”에 매핑하는 메트릭으로 정렬합니다. 파이썬에서는, list.sort() 메서드의 key 인자를 사용하십시오:

Isorted = L[:]
Isorted.sort(key=lambda s: int(s[10:15]))

한 리스트를 다른 리스트의 값으로 정렬하려면 어떻게 해야 합니까?

그것들을 튜플의 이터레이터로 병합하고, 결과 리스트를 정렬한 다음, 원하는 요소를 선택하십시오.

>>> list1 = ["what", "I'm", "sorting", "by"]
>>> list2 = ["something", "else", "to", "sort"]
>>> pairs = zip(list1, list2)
>>> pairs = sorted(pairs)
>>> pairs
[("I'm", 'else'), ('by', 'sort'), ('sorting', 'to'), ('what', 'something')]
>>> result = [x[1] for x in pairs]
>>> result
['else', 'sort', 'to', 'something']

객체

클래스는 무엇입니까?

클래스는 class 문을 실행하여 만든 특정 객체 형입니다. 클래스 객체는 인스턴스 객체를 만들기 위한 주형으로 사용되며, 데이터형과 관련된 데이터(어트리뷰트)와 코드(메서드)를 모두 내장합니다.

클래스는 베이스 클래스라고 하는 하나 이상의 다른 클래스를 기반으로 할 수 있습니다. 그러면 베이스 클래스의 어트리뷰트와 메서드를 상속합니다. 이는 상속을 통해 객체 모델을 점진적으로 재정의할 수 있도록 합니다. 우편함에 대한 기본 접근자 메서드를 제공하는 일반 Mailbox 클래스와 다양한 특정 사서함 형식을 처리하는 MboxMailbox, MaildirMailbox, OutlookMailbox와 같은 서브 클래스가 있을 수 있습니다.

메서드는 무엇입니까?

메서드는 일반적으로 x.name(arguments...)로 호출하는 어떤 객체 x의 함수입니다. 메서드는 클래스 정의 내에서 함수로 정의됩니다:

class C:
    def meth(self, arg):
        return arg * 2 + self.attribute

self는 무엇입니까?

self는 단지 메서드의 첫 번째 인자를 위한 관례적 이름입니다. meth(self, a, b, c)로 정의된 메서드는 정의가 등장한 클래스의 어떤 인스턴스 x에 대해 x.meth(a, b, c)로 호출되어야 합니다; 호출된 메서드는 meth(x, a, b, c)처럼 호출되었다고 생각합니다.

메서드 정의와 호출에서 ‘self’를 명시적으로 사용해야 하는 이유는 무엇입니까? 도 참조하십시오.

객체가 주어진 클래스나 그 서브 클래스의 인스턴스인지 어떻게 확인합니까?

Use the built-in function isinstance(obj, cls). You can check if an object is an instance of any of a number of classes by providing a tuple instead of a single class, e.g. isinstance(obj, (class1, class2, ...)), and can also check whether an object is one of Python’s built-in types, e.g. isinstance(obj, str) or isinstance(obj, (int, float, complex)).

Note that isinstance() also checks for virtual inheritance from an abstract base class. So, the test will return True for a registered class even if hasn’t directly or indirectly inherited from it. To test for “true inheritance”, scan the MRO of the class:

from collections.abc import Mapping

class P:
     pass

class C(P):
    pass

Mapping.register(P)

>>> c = C()
>>> isinstance(c, C)        # direct
True
>>> isinstance(c, P)        # indirect
True
>>> isinstance(c, Mapping)  # virtual
True

# Actual inheritance chain
>>> type(c).__mro__
(<class 'C'>, <class 'P'>, <class 'object'>)

# Test for "true inheritance"
>>> Mapping in type(c).__mro__
False

대부분의 프로그램은 사용자 정의 클래스에서 isinstance()를 자주 사용하지 않음에 유의하십시오. 클래스를 직접 개발하고 있다면, 더 적절한 객체 지향 스타일은 객체의 클래스를 확인하고 클래스에 따라 다른 작업을 수행하는 대신 특정 동작을 캡슐화하는 클래스의 메서드를 정의하는 것입니다. 예를 들어, 무언가를 수행하는 함수가 있다면:

def search(obj):
    if isinstance(obj, Mailbox):
        ...  # code to search a mailbox
    elif isinstance(obj, Document):
        ...  # code to search a document
    elif ...

더 나은 접근법은 모든 클래스에서 search() 메서드를 정의하고 단지 그것을 호출하는 것입니다:

class Mailbox:
    def search(self):
        ...  # code to search a mailbox

class Document:
    def search(self):
        ...  # code to search a document

obj.search()

위임이란 무엇입니까?

위임(delegation)은 객체 지향 기법(디자인 패턴이라고도 합니다)입니다. x 객체가 있고 메서드 중 하나의 동작을 변경하고 싶다고 가정해 봅시다. 변경하려는 메서드의 새로운 구현을 제공하고 다른 모든 메서드를 x의 해당 메서드에 위임하는 새 클래스를 만들 수 있습니다.

파이썬 프로그래머는 쉽게 위임을 구현할 수 있습니다. 예를 들어, 다음 클래스는 파일처럼 동작하지만, 기록되는 모든 데이터를 대문자로 변환하는 클래스를 구현합니다:

class UpperOut:

    def __init__(self, outfile):
        self._outfile = outfile

    def write(self, s):
        self._outfile.write(s.upper())

    def __getattr__(self, name):
        return getattr(self._outfile, name)

Here the UpperOut class redefines the write() method to convert the argument string to uppercase before calling the underlying self._outfile.write() method. All other methods are delegated to the underlying self._outfile object. The delegation is accomplished via the __getattr__() method; consult the language reference for more information about controlling attribute access.

Note that for more general cases delegation can get trickier. When attributes must be set as well as retrieved, the class must define a __setattr__() method too, and it must do so carefully. The basic implementation of __setattr__() is roughly equivalent to the following:

class X:
    ...
    def __setattr__(self, name, value):
        self.__dict__[name] = value
    ...

Many __setattr__() implementations call object.__setattr__() to set an attribute on self without causing infinite recursion:

class X:
    def __setattr__(self, name, value):
        # Custom logic here...
        object.__setattr__(self, name, value)

Alternatively, it is possible to set attributes by inserting entries into self.__dict__ directly.

How do I call a method defined in a base class from a derived class that extends it?

내장 super() 함수를 사용하십시오:

class Derived(Base):
    def meth(self):
        super().meth()  # calls Base.meth

In the example, super() will automatically determine the instance from which it was called (the self value), look up the method resolution order (MRO) with type(self).__mro__, and return the next in line after Derived in the MRO: Base.

베이스 클래스를 쉽게 변경할 수 있도록 코드를 구성하려면 어떻게 해야 합니까?

베이스 클래스를 별칭에 대입하고 별칭에서 파생할 수 있습니다. 그러면 별칭에 대입된 값만 변경하면 됩니다. 또한 이 트릭은 사용할 베이스 클래스를 동적으로 (예를 들어 자원의 가용성에 따라) 결정하려는 경우에도 유용합니다. 예:

class Base:
    ...

BaseAlias = Base

class Derived(BaseAlias):
    ...

정적 클래스 데이터와 정적 클래스 메서드를 만들려면 어떻게 해야 합니까?

(C++나 Java의 의미에서) 정적 데이터와 정적 메서드 모두 파이썬에서 지원됩니다.

정적 데이터의 경우, 단순히 클래스 어트리뷰트를 정의하십시오. 어트리뷰트에 새 값을 대입하려면, 대입에서 클래스 이름을 명시적으로 사용해야 합니다:

class C:
    count = 0   # number of times C.__init__ called

    def __init__(self):
        C.count = C.count + 1

    def getcount(self):
        return C.count  # or return self.count

c 자체나 c.__class__에서 C로 돌아가는 베이스 클래스 검색 경로에 놓인 일부 클래스에 의해 재정의되지 않는 한, c.count는 isinstance(c, C)가 성립하는 모든 c에 대해 C.count를 참조합니다.

주의: C의 메서드 내에서, self.count = 42와 같은 대입은 self의 자체 딕셔너리에 “count”라는 새롭고 관련이 없는 인스턴스를 만듭니다. 클래스 정적 데이터 이름의 재연결은 항상 메서드 내부에 있는지에 관계없이 클래스를 지정해야 합니다:

C.count = 314

정적 메서드도 가능합니다:

class C:
    @staticmethod
    def static(arg1, arg2, arg3):
        # No 'self' parameter!
        ...

그러나, 정적 메서드의 효과를 얻는 훨씬 간단한 방법은 단순한 모듈 수준 함수를 사용하는 것입니다:

def getcount():
    return C.count

여러분의 코드가 모듈 당 하나의 클래스 (또는 밀접하게 관련된 클래스 계층 구조)를 정의하도록 구조화되었다면, 이것이 원하는 캡슐화를 제공합니다.

파이썬에서 생성자(또는 메서드)를 어떻게 재정의할 수 있습니까?

이 답변은 실제로 모든 메서드에 적용되지만, 질문은 일반적으로 생성자 문맥에서 가장 먼저 나옵니다.

C++에서는 다음과 같이 작성합니다

class C {
    C() { cout << "No arguments\n"; }
    C(int i) { cout << "Argument is " << i << "\n"; }
}

파이썬에서는 기본 인자를 사용하여 모든 경우를 다루는 단일 생성자를 작성해야 합니다. 예를 들면:

class C:
    def __init__(self, i=None):
        if i is None:
            print("No arguments")
        else:
            print("Argument is", i)

이것은 완전히 동등하지는 않지만, 실제로는 아주 가깝습니다.

가변 길이 인자 목록을 시도할 수도 있습니다, 예를 들어:

def __init__(self, *args):
    ...

같은 접근법이 모든 메서드 정의에서도 동작합니다.

__spam을 사용하려고 하는데 _SomeClassName__spam에 대한 에러가 발생합니다.

이중 선행 밑줄이 있는 변수 이름은 클래스 비공개(private) 변수를 정의하는 간단하지만, 효과적인 방법을 제공하기 위해 “뒤섞입니다(mangled)”. __spam 형식(적어도 두 개의 선행 밑줄, 최대 하나의 후행 밑줄)의 모든 식별자는 _classname__spam으로 텍스트 대체되는데, 여기서 classname 은 모든 선행 밑줄이 제거된 현재 클래스 이름입니다.

The identifier can be used unchanged within the class, but to access it outside the class, the mangled name must be used:

class A:
    def __one(self):
        return 1
    def two(self):
        return 2 * self.__one()

class B(A):
    def three(self):
        return 3 * self._A__one()

four = 4 * A()._A__one()

In particular, this does not guarantee privacy since an outside user can still deliberately access the private attribute; many Python programmers never bother to use private variable names at all.

더 보기

The private name mangling specifications for details and special cases.

내 클래스는 __del__을 정의하지만 객체를 삭제할 때 호출되지 않습니다.

몇 가지 가능한 이유가 있습니다.

The del statement does not necessarily call __del__() – it simply decrements the object’s reference count, and if this reaches zero __del__() is called.

If your data structures contain circular links (e.g. a tree where each child has a parent reference and each parent has a list of children) the reference counts will never go back to zero. Once in a while Python runs an algorithm to detect such cycles, but the garbage collector might run some time after the last reference to your data structure vanishes, so your __del__() method may be called at an inconvenient and random time. This is inconvenient if you’re trying to reproduce a problem. Worse, the order in which object’s __del__() methods are executed is arbitrary. You can run gc.collect() to force a collection, but there are pathological cases where objects will never be collected.

Despite the cycle collector, it’s still a good idea to define an explicit close() method on objects to be called whenever you’re done with them. The close() method can then remove attributes that refer to subobjects. Don’t call __del__() directly – __del__() should call close() and close() should make sure that it can be called more than once for the same object.

순환 참조를 피하는 또 다른 방법은 weakref 모듈을 사용하는 것입니다. 이 모듈은 참조 횟수를 늘리지 않고 객체를 가리킬 수 있도록 합니다. 예를 들어, 트리 자료 구조는 부모와 형제 참조에 대해 약한 참조를 사용해야 합니다 (이런 것들이 필요하다면!).

Finally, if your __del__() method raises an exception, a warning message is printed to sys.stderr.

주어진 클래스의 모든 인스턴스 목록을 어떻게 얻습니까?

파이썬은 클래스(또는 내장형)의 모든 인스턴스를 추적하지 않습니다. 클래스 생성자가 각 인스턴스에 대한 약한 참조 리스트를 유지하여 모든 인스턴스를 추적하도록 프로그래밍 할 수 있습니다.

id()의 결과가 고유하지 않은 것처럼 보이는 이유는 무엇입니까?

id() 내장은 객체 수명 동안 고유하도록 보장되는 정수를 반환합니다. CPython에서는 이것이 객체의 메모리 주소이므로, 객체가 메모리에서 삭제된 후 새로 만들어진 다음 객체가 메모리의 같은 위치에 할당되는 경우가 자주 발생합니다. 다음과 같이 예시할 수 있습니다:

>>> id(1000)
13901272
>>> id(2000)
13901272

두 개의 id는 다른 정수 객체에 속하는데, id() 호출 실행 앞에 만들어지고, 호출 직후 삭제됩니다. id를 검사하려는 객체가 여전히 살아 있도록 하려면, 그 객체에 대한 다른 참조를 만드십시오:

>>> a = 1000; b = 2000
>>> id(a)
13901272
>>> id(b)
13891296

is 연산자를 사용한 아이덴티티 검사는 언제 신뢰할 수 있습니까?

is 연산자는 객체 아이덴티티를 검사합니다. 검사 a is b는 id(a) == id(b)와 동등합니다.

아이덴티티 검사의 가장 중요한 속성은 객체가 항상 자신과 동일하고 a is a는 항상 True를 반환한다는 것입니다. 아이덴티티 검사는 일반적으로 동등성 검사보다 빠릅니다. 동등성 검사와 달리, 아이덴티티 테스트는 불리언 True나 False를 반환함이 보장됩니다.

그러나, 객체 아이덴티티가 보장될 때 아이덴티티 검사가 동등성 검사를 대체할 수 있습니다. 일반적으로, 아이덴티티가 보장되는 세 가지 상황이 있습니다:

1) Assignments create new names but do not change object identity. After the assignment new = old, it is guaranteed that new is old.

2) Putting an object in a container that stores object references does not change object identity. After the list assignment s[0] = x, it is guaranteed that s[0] is x.

3) If an object is a singleton, it means that only one instance of that object can exist. After the assignments a = None and b = None, it is guaranteed that a is b because None is a singleton.

대부분의 다른 상황에서는 아이덴티티 검사가 권장되지 않으며 동등성 테스트가 선호됩니다. 특히, 싱글톤이 보장되지 않는 int와 str과 같은 상수를 확인하는 데 아이덴티티 검사를 사용해서는 안 됩니다:

>>> a = 1000
>>> b = 500
>>> c = b + 500
>>> a is c
False

>>> a = 'Python'
>>> b = 'Py'
>>> c = b + 'thon'
>>> a is c
False

마찬가지로, 가변 컨테이너의 새 인스턴스는 절대 동일하지 않습니다:

>>> a = []
>>> b = []
>>> a is b
False

표준 라이브러리 코드에서, 아이덴티티 검사를 올바르게 사용하는 몇 가지 일반적인 패턴을 볼 수 있습니다:

1) As recommended by PEP 8 [https://peps.python.org/pep-0008/], an identity test is the preferred way to check for None. This reads like plain English in code and avoids confusion with other objects that may have boolean values that evaluate to false.

2) Detecting optional arguments can be tricky when None is a valid input value. In those situations, you can create a singleton sentinel object guaranteed to be distinct from other objects. For example, here is how to implement a method that behaves like dict.pop():

_sentinel = object()

def pop(self, key, default=_sentinel):
    if key in self:
        value = self[key]
        del self[key]
        return value
    if default is _sentinel:
        raise KeyError(key)
    return default

3) Container implementations sometimes need to augment equality tests with identity tests. This prevents the code from being confused by objects such as float('NaN') that are not equal to themselves.

For example, here is the implementation of collections.abc.Sequence.__contains__():

def __contains__(self, value):
    for v in self:
        if v is value or v == value:
            return True
    return False

How can a subclass control what data is stored in an immutable instance?

When subclassing an immutable type, override the __new__() method instead of the __init__() method. The latter only runs after an instance is created, which is too late to alter data in an immutable instance.

All of these immutable classes have a different signature than their parent class:

from datetime import date

class FirstOfMonthDate(date):
    "Always choose the first day of the month"
    def __new__(cls, year, month, day):
        return super().__new__(cls, year, month, 1)

class NamedInt(int):
    "Allow text names for some numbers"
    xlat = {'zero': 0, 'one': 1, 'ten': 10}
    def __new__(cls, value):
        value = cls.xlat.get(value, value)
        return super().__new__(cls, value)

class TitleStr(str):
    "Convert str to name suitable for a URL path"
    def __new__(cls, s):
        s = s.lower().replace(' ', '-')
        s = ''.join([c for c in s if c.isalnum() or c == '-'])
        return super().__new__(cls, s)

The classes can be used like this:

>>> FirstOfMonthDate(2012, 2, 14)
FirstOfMonthDate(2012, 2, 1)
>>> NamedInt('ten')
10
>>> NamedInt(20)
20
>>> TitleStr('Blog: Why Python Rocks')
'blog-why-python-rocks'

How do I cache method calls?

The two principal tools for caching methods are functools.cached_property() and functools.lru_cache(). The former stores results at the instance level and the latter at the class level.

The cached_property approach only works with methods that do not take any arguments. It does not create a reference to the instance. The cached method result will be kept only as long as the instance is alive.

The advantage is that when an instance is no longer used, the cached method result will be released right away. The disadvantage is that if instances accumulate, so too will the accumulated method results. They can grow without bound.

The lru_cache approach works with methods that have hashable arguments. It creates a reference to the instance unless special efforts are made to pass in weak references.

The advantage of the least recently used algorithm is that the cache is bounded by the specified maxsize. The disadvantage is that instances are kept alive until they age out of the cache or until the cache is cleared.

This example shows the various techniques:

class Weather:
    "Lookup weather information on a government website"

    def __init__(self, station_id):
        self._station_id = station_id
        # The _station_id is private and immutable

    def current_temperature(self):
        "Latest hourly observation"
        # Do not cache this because old results
        # can be out of date.

    @cached_property
    def location(self):
        "Return the longitude/latitude coordinates of the station"
        # Result only depends on the station_id

    @lru_cache(maxsize=20)
    def historic_rainfall(self, date, units='mm'):
        "Rainfall on a given date"
        # Depends on the station_id, date, and units.

The above example assumes that the station_id never changes. If the relevant instance attributes are mutable, the cached_property approach can’t be made to work because it cannot detect changes to the attributes.

To make the lru_cache approach work when the station_id is mutable, the class needs to define the __eq__() and __hash__() methods so that the cache can detect relevant attribute updates:

class Weather:
    "Example with a mutable station identifier"

    def __init__(self, station_id):
        self.station_id = station_id

    def change_station(self, station_id):
        self.station_id = station_id

    def __eq__(self, other):
        return self.station_id == other.station_id

    def __hash__(self):
        return hash(self.station_id)

    @lru_cache(maxsize=20)
    def historic_rainfall(self, date, units='cm'):
        'Rainfall on a given date'
        # Depends on the station_id, date, and units.

모듈

.pyc 파일을 어떻게 만듭니까?

모듈이 처음 임포트 될 때 (또는 현재 컴파일된 파일이 만들어진 후 소스 파일이 변경되었을 때) 컴파일된 코드를 포함하는 .pyc 파일은 .py 파일을 포함하는 디렉터리의 __pycache__ 서브 디렉터리에 만들어져야 합니다. .pyc 파일은 .py 파일과 같은 이름으로 시작하고, .pyc로 끝나며, 파일을 만든 특정 python 바이너리 파일에 종속되는 중간 구성 요소를 갖는 파일명을 갖습니다. (자세한 내용은 PEP 3147 [https://peps.python.org/pep-3147/]을 참조하십시오.)

.pyc 파일이 만들어지지 않을 수 있는 한 가지 이유는 소스 파일이 포함된 디렉터리의 권한 문제입니다. 즉, __pycache__ 서브 디렉터리를 만들 수 없다는 뜻입니다. 예를 들어, 한 사용자로 개발했지만 다른 사용자로 실행하는 경우에 이런 일이 일어날 수 있습니다, 가령 웹 서버로 테스트하고 있을 때입니다.

PYTHONDONTWRITEBYTECODE 환경 변수가 설정되어 있지 않은 한, 모듈을 임포트 하고 파이썬이 __pycache__ 서브 디렉터리를 만들고 컴파일된 모듈을 그 서브 디렉터리에 쓸 수 있는 능력(권한, 여유 공간 등)이 있으면 .pyc 파일의 생성은 자동입니다.

최상위 스크립트에서 파이썬을 실행하는 것은 임포트로 간주하지 않으며 .pyc가 만들어지지 않습니다. 예를 들어, 다른 모듈 xyz.py를 임포트 하는 최상위 모듈 foo.py가 있을 때, (python foo.py를 셸 명령으로 입력하여) foo를 실행하면, xyz를 임포트 하기 때문에 xyz에 대해 .pyc가 만들어지지만, foo.py를 임포트 하지 않기 때문에 foo에 대해서는 .pyc 파일이 만들어지지 않습니다.

foo에 대한 .pyc 파일을 만들 필요가 있으면 – 즉, 임포트 되지 않는 모듈에 대한 .pyc 파일을 만들려면 – py_compile과 compileall 모듈을 사용할 수 있습니다.

py_compile 모듈은 임의의 모듈을 수동으로 컴파일할 수 있습니다. 한 가지 방법은 해당 모듈에서 compile() 함수를 대화식으로 사용하는 것입니다:

>>> import py_compile
>>> py_compile.compile('foo.py')

이것은 .pyc를 foo.py와 같은 위치에 있는 __pycache__ 서브 디렉터리에 기록합니다 (또는 선택적 매개변수 cfile로 이를 재정의할 수 있습니다).

compileall 모듈을 사용하여 디렉터리의 모든 파일을 자동으로 컴파일할 수도 있습니다. compileall.py를 실행하고 컴파일할 파이썬 파일이 포함된 디렉터리의 경로를 제공하여 셸 프롬프트에서 이를 수행할 수 있습니다:

python -m compileall .

현재 모듈 이름을 어떻게 찾습니까?

모듈은 사전 정의된 전역 변수 __name__을 봄으로써 모듈 자신의 이름을 찾을 수 있습니다. 값이 '__main__'이면, 프로그램이 스크립트로 실행 중입니다. 일반적으로 모듈을 임포트 해서 사용하는 많은 모듈은 명령 줄 인터페이스나 자체 테스트를 제공하며, __name__을 확인한 후에 만 이 코드를 실행합니다:

def main():
    print('Running test...')
    ...

if __name__ == '__main__':
    main()

서로 임포트 하는 모듈을 어떻게 만들 수 있습니까?

다음 모듈이 있다고 가정하십시오:

foo.py:

from bar import bar_var
foo_var = 1

bar.py:

from foo import foo_var
bar_var = 2

문제는 인터프리터가 다음 단계를 수행한다는 것입니다:

main imports foo

Empty globals for foo are created

foo is compiled and starts executing

foo imports bar

Empty globals for bar are created

bar is compiled and starts executing

bar imports foo (which is a no-op since there already is a module named foo)

The import mechanism tries to read foo_var from foo globals, to set bar.foo_var = foo.foo_var

마지막 단계가 실패합니다. 파이썬이 아직 foo를 인터프리트 하는 것을 완료하지 않았고 foo의 전역 기호 딕셔너리가 여전히 비어 있기 때문입니다.

import foo를 사용하고 전역 코드에서 foo.foo_var에 액세스하려고 할 때도 같은 일이 일어납니다.

이 문제에 대해 가능한 (최소한) 세 가지 해결 방법이 있습니다.

Guido van Rossum은 from <module> import ...을 아예 사용하지 말고, 모든 코드를 함수 내에 배치할 것을 권장합니다. 전역 변수와 클래스 변수의 초기화는 상수나 내장 함수만 사용해야 합니다. 이것은 임포트 된 모듈의 모든 것이 <module>.<name>으로 참조됨을 의미합니다.

Jim Roskind는 각 모듈에서 다음 순서로 단계를 수행할 것을 제안합니다:

내보내기 (전역, 함수 및 베이스 클래스를 임포트 할 필요가 없는 클래스)

import 문

활성 코드 (임포트 된 값에서 초기화된 전역 포함).

Van Rossum doesn’t like this approach much because the imports appear in a strange place, but it does work.

Matthias Urlichs는 처음부터 재귀 임포트가 필요하지 않도록 코드를 재구성할 것을 권합니다.

이 해결 방법들은 상호 배타적이지 않습니다.

__import__(‘x.y.z’)는 <module ‘x’>를 반환합니다; z를 어떻게 얻습니까?

importlib의 편의 함수 import_module()을 대신 사용하는 곳을 고려하십시오:

z = importlib.import_module('x.y.z')

임포트 된 모듈을 편집하고 다시 임포트 할 때, 변경 사항이 표시되지 않습니다. 왜 이런 일이 발생합니까?

효율성뿐만 아니라 일관성의 이유로, 파이썬은 모듈을 처음 임포트 할 때만 모듈 파일을 읽습니다. 그렇지 않으면, 각 모듈이 같은 기본 모듈을 임포트 하는 많은 모듈로 구성된 프로그램에서, 기본 모듈을 여러 번 구문 분석하고 다시 구문 분석하게 됩니다. 변경된 모듈을 강제로 다시 읽으려면, 다음과 같이 하십시오:

import importlib
import modname
importlib.reload(modname)

경고: 이 기법은 100% 확실하지 않습니다. 특히, 다음과 같은 문장을 포함하는 모듈은

from modname import some_objects

임포트 된 객체의 이전 버전으로 계속 작업합니다. 모듈에 클래스 정의가 포함되면, 새 클래스 정의를 사용하도록 기존 클래스 인스턴스가 갱신되지 않습니다. 이것은 다음과 같은 역설적인 동작으로 이어집니다:

>>> import importlib
>>> import cls
>>> c = cls.C()                # Create an instance of C
>>> importlib.reload(cls)
<module 'cls' from 'cls.py'>
>>> isinstance(c, cls.C)       # isinstance is false?!?
False

클래스 객체의 “아이덴티티”를 인쇄하면 문제의 본질이 분명해집니다:

>>> hex(id(c.__class__))
'0x7352a0'
>>> hex(id(cls.C))
'0x4198d0'

설계와 역사 FAQ

목차

설계와 역사 FAQ

파이썬은 왜 문장의 그룹화에 들여쓰기를 사용합니까?

간단한 산술 연산으로 이상한 결과가 나오는 이유는 무엇입니까?

부동 소수점 계산이 왜 그렇게 부정확합니까?

파이썬 문자열이 불변인 이유는 무엇입니까?

메서드 정의와 호출에서 ‘self’를 명시적으로 사용해야 하는 이유는 무엇입니까?

표현식에서 대입을 사용할 수 없는 이유는 무엇입니까?

파이썬은 왜 일부 기능(예를 들어 list.index())에는 메서드를 사용하고 다른 기능(예를 들어 len(list))에는 함수를 사용합니까?

join()이 리스트나 튜플 메서드가 아니라 문자열 메서드인 이유는 무엇입니까?

예외는 얼마나 빠릅니까?

파이썬에 switch 나 case 문이 없는 이유는 무엇입니까?

OS별 스레드 구현에 의존하는 대신 인터프리터에서 스레드를 에뮬레이션할 수 없습니까?

람다 표현식이 문장을 포함할 수 없는 이유는 무엇입니까?

파이썬을 기계 코드, C 또는 다른 언어로 컴파일 할 수 있습니까?

파이썬은 메모리를 어떻게 관리합니까?

CPython이 더 전통적인 가비지 수거 체계를 사용하지 않는 이유는 무엇입니까?

CPython이 종료될 때 모든 메모리가 해제되지 않는 이유는 무엇입니까?

별도의 튜플과 리스트 데이터형이 있는 이유는 무엇입니까?

CPython에서 리스트는 어떻게 구현됩니까?

CPython에서 딕셔너리는 어떻게 구현됩니까?

딕셔너리 키가 불변이어야 하는 이유는 무엇입니까?

list.sort()가 정렬된 리스트를 반환하지 않는 이유는 무엇입니까?

파이썬에서 인터페이스 명세를 어떻게 지정하고 강제합니까?

goto가 없는 이유는 무엇입니까?

날 문자열(r-strings)이 역 슬래시로 끝날 수 없는 이유는 무엇입니까?

왜 파이썬에는 어트리뷰트 대입을 위한 “with” 문이 없습니까?

Why don’t generators support the with statement?

if/while/def/class 문에 콜론이 필요한 이유는 무엇입니까?

파이썬은 왜 리스트와 튜플 끝에 쉼표를 허용합니까?

파이썬은 왜 문장의 그룹화에 들여쓰기를 사용합니까?

Guido van Rossum은 그룹화에 들여쓰기를 사용하는 것이 매우 우아하고 일반적인 파이썬 프로그램의 명확성에 크게 기여한다고 믿습니다. 대부분의 사람은 시간이 좀 흐른 후에 이 기능을 사랑하는 법을 배웁니다.

시작/끝 괄호가 없기 때문에 구문 분석기와 사람 독자가 인식하는 그룹 간에 불일치가 있을 수 없습니다. 때때로 C 프로그래머는 다음과 같은 코드 조각을 만나게 됩니다:

if (x <= y)
        x++;
        y--;
z++;

조건이 참이면 x++ 문만 실행되지만, 들여쓰기는 많은 사람이 그렇지 않다고 믿게 만듭니다. 경험 많은 C 프로그래머조차도 x > y일 때도 y가 감소하는 이유를 궁금해하면서 오래 들여다볼 때가 있습니다.

시작/끝 괄호가 없기 때문에, 파이썬은 코딩 스타일 충돌이 훨씬 적습니다. C에서는 중괄호를 배치하는 여러 가지 방법이 있습니다. 특정 스타일을 사용하여 코드를 읽고 쓰는 데 익숙해지면, 다른 스타일로 읽을 (또는 작성해야 할) 때 다소 불편함을 느끼는 것은 정상입니다.

많은 코딩 스타일은 시작/끝 괄호를 그 자신만의 줄에 배치합니다. 이로 인해 프로그램이 상당히 길어지고 귀중한 화면 공간이 낭비되어, 프로그램을 조망하기가 더 어려워집니다. 이상적으로는, 함수가 한 화면에 맞아야 합니다 (가령, 20–30줄). 20줄의 파이썬은 C의 20줄보다 훨씬 더 많은 작업을 수행할 수 있습니다. 이것은 시작/끝 괄호가 필요 없기 때문 만은 아닙니다만 – 선언이 없는 것과 고수준의 데이터형도 기여합니다 – 들여쓰기 기반 문법은 확실히 도움이 됩니다.

간단한 산술 연산으로 이상한 결과가 나오는 이유는 무엇입니까?

다음 질문을 보십시오.

부동 소수점 계산이 왜 그렇게 부정확합니까?

사용자는 종종 다음과 같은 결과에 놀라게 됩니다:

>>> 1.2 - 1.0
0.19999999999999996

그리고 이것을 파이썬의 버그라고 생각합니다. 그렇지 않습니다. 이것은 파이썬과 거의 관련이 없으며, 하부 플랫폼이 부동 소수점 숫자를 처리하는 방법과 훨씬 더 관련이 있습니다.

CPython의 float 형은 저장을 위해 C double을 사용합니다. float 객체의 값은 고정 정밀도(일반적으로 53비트)의 이진 부동 소수점에 저장되고 파이썬은 부동 소수점 연산을 수행하는 데 C 연산을 사용하며, 이는 다시 프로세서의 하드웨어 구현에 의존합니다. 즉, 부동 소수점 연산에 관한 한, 파이썬은 C와 Java를 포함한 많은 널리 알려진 언어들처럼 작동합니다.

Many numbers that can be written easily in decimal notation cannot be expressed exactly in binary floating point. For example, after:

>>> x = 1.2

이후에, x에 대해 저장된 값은 10진수 값 1.2에 대한 (매우 좋은) 근사치이지만, 정확히 같지는 않습니다. 일반적인 기계에서 실제 저장되는 값은 다음과 같습니다:

1.0011001100110011001100110011001100110011001100110011 (binary)

이것은 정확하게는 다음과 같습니다:

1.1999999999999999555910790149937383830547332763671875 (decimal)

53비트의 일반적인 정밀도는 파이썬 부동 소수점에 15–16자리의 10진수 정확도를 제공합니다.

For a fuller explanation, please see the floating-point arithmetic chapter in the Python tutorial.

파이썬 문자열이 불변인 이유는 무엇입니까?

몇 가지 장점이 있습니다.

하나는 성능입니다: 문자열이 불변임을 안다는 것은 만들 때 이를 위한 공간을 할당할 수 있다는 것을 의미하며, 스토리지 요구 사항은 고정되고 변경되지 않습니다. 이것은 또한 튜플과 리스트를 구분하는 이유 중 하나입니다.

또 다른 장점은 파이썬의 문자열을 숫자만큼 “기본적”으로 간주한다는 것입니다. 어떤 방법도 값 8을 다른 것으로 변경하지 않으며, 파이썬에서는 어떤 방법도 문자열 “eight”을 다른 것으로 변경하지 않습니다.

메서드 정의와 호출에서 ‘self’를 명시적으로 사용해야 하는 이유는 무엇입니까?

아이디어는 Modula-3에서 빌렸습니다. 여러 가지 이유로 매우 유용합니다.

첫째, 로컬 변수 대신 메서드나 인스턴스 어트리뷰트를 사용하고 있다는 것이 더 분명합니다. self.x나 self.meth()를 읽으면 클래스 정의를 기억하지 못하더라도 인스턴스 변수나 메서드가 사용된다는 것을 분명히 알 수 있습니다. C++에서는, 지역 변수 선언이 없는 것으로 구분할 수 있습니다 (전역은 드물거나 쉽게 인식할 수 있다고 가정할 때) – 하지만 파이썬에서는, 지역 변수 선언이 없어서, 확실히 하려면 클래스 정의를 찾아야 합니다. 일부 C++와 Java 코딩 표준에서는 인스턴스 어트리뷰트에 m_ 접두어를 요청합니다, 따라서 이러한 명시성은 이런 언어들에서도 여전히 유용합니다.

Second, it means that no special syntax is necessary if you want to explicitly reference or call the method from a particular class. In C++, if you want to use a method from a base class which is overridden in a derived class, you have to use the :: operator – in Python you can write baseclass.methodname(self, <argument list>). This is particularly useful for __init__() methods, and in general in cases where a derived class method wants to extend the base class method of the same name and thus has to call the base class method somehow.

마지막으로, 인스턴스 변수의 경우 대입과 관련된 문법 문제를 해결합니다: 파이썬의 지역 변수는 (정의상!) 함수 본문에서 값이 대입되는 (그리고 전역으로 명시적으로 선언되지 않은) 변수이기 때문에, 인터프리터에게 대입이 지역 변수가 아니라 인스턴스 변수에 대한 대입이라는 것을 알릴 방법이 있어야 하고, (효율성의 측면에서) 구문적이면 좋습니다. C++는 선언을 통해 이 작업을 수행하지만, 파이썬에는 선언이 없어서 이러한 목적으로만 문법을 도입해야 하는 것은 유감입니다. 명시적 self.var를 사용하면 이 문제가 잘 해결됩니다. 마찬가지로, 인스턴스 변수를 사용하는 경우, self.var라고 써야 한다는 것은, 메서드 내에서 정규화되지 않은 이름에 대한 참조가 인스턴스의 디렉터리를 검색할 필요가 없음을 의미합니다. 다시 말해, 지역 변수와 인스턴스 변수는 두 개의 서로 다른 이름 공간에 있으며, 사용할 이름 공간을 파이썬에 알려야 합니다.

표현식에서 대입을 사용할 수 없는 이유는 무엇입니까?

파이썬 3.8부터, 가능합니다!

Assignment expressions using the walrus operator := assign a variable in an expression:

while chunk := fp.read(200):
   print(chunk)

자세한 정보는 PEP 572 [https://peps.python.org/pep-0572/]를 참조하십시오.

파이썬은 왜 일부 기능(예를 들어 list.index())에는 메서드를 사용하고 다른 기능(예를 들어 len(list))에는 함수를 사용합니까?

Guido가 말했듯이:

(a) 일부 연산의 경우, 전위 표기법(prefix notation)이 후위(postfix) 표기법보다 더 잘 읽힙니다 – 전위 (그리고 중위(infix)!) 연산은 수학에서 오랜 전통을 가지고 있는데, 수학자가 문제에 대해 생각하는 데 시각적으로 도움이 되는 표기법을 좋아하는 곳입니다. x*(a+b) 와 같은 공식을 x*a + x*b 로 다시 작성하기 쉬운 것과 원시 OO 표기법을 사용하여 같은 작업을 수행할 때의 어색함을 비교해 보십시오.

(b) len(x) 라는 코드를 읽을 때 저는 무언가의 길이를 요구하고 있다는 것을 압니다. 이것은 저에게 두 가지를 알려줍니다: 결과는 정수이고, 인자는 일종의 컨테이너입니다. 반대로, x.len() 을 읽을 때, x가 인터페이스를 구현하거나 표준 len() 이 있는 클래스에서 상속하는 일종의 컨테이너라는 것을 이미 알고 있어야 합니다. 매핑을 구현하지 않는 클래스에 get() 이나 keys() 메서드가 있거나, 파일이 아닌 것에 write() 메서드가 있을 때 때때로 겪는 혼란을 보십시오.

—https://mail.python.org/pipermail/python-3000/2006-November/004643.html

join()이 리스트나 튜플 메서드가 아니라 문자열 메서드인 이유는 무엇입니까?

항상 string 모듈의 함수를 사용하여 제공되었던 것과 같은 기능을 제공하는 메서드가 추가된, 파이썬 1.6부터 문자열은 다른 표준형과 훨씬 더 비슷해졌습니다. 이러한 새로운 메서드의 대부분은 널리 받아들여졌지만, 일부 프로그래머가 불편해하는 것은 다음과 같습니다:

", ".join(['1', '2', '4', '8', '16'])

이것은 다음과 같은 결과를 제공합니다:

"1, 2, 4, 8, 16"

이 사용법에 대해 두 가지 자주 나오는 반론이 있습니다.

첫 번째는 “문자열 리터럴(문자열 상수)의 메서드를 사용하는 것이 정말 보기 흉합니다”라는 줄이 따라옵니다. 이에 대한 대답은 그럴 수 있지만, 문자열 리터럴은 그저 고정된 값일 뿐이라는 것입니다. 메서드가 문자열에 연결된 이름에 허용된다면, 리터럴에서 사용할 수 없게 만드는 논리적 이유가 없습니다.

두 번째 이의는 보통 다음과 같이 표현됩니다: “나는 시퀀스가 멤버를 문자열 상수로 연결하라고 말하고 있습니다”. 슬프게도, 당신은 그렇지 않습니다. 어떤 이유로 split()를 문자열 메서드로 사용하는 데 훨씬 덜 어려움을 겪는 것 같습니다, 그럴 때 다음과 같은 표현이

"1, 2, 4, 8, 16".split(", ")

문자열 리터럴에게 주어진 구분자(또는, 기본적으로, 임의의 공백 연속)로 구분된 하위 문자열을 반환하도록 하는 명령임을 쉽게 알 수 있기 때문입니다.

join()은 문자열 메서드입니다. 사용 시 구분자 문자열에게 문자열 시퀀스를 이터레이트 하고 인접한 요소 사이에 자신을 삽입하도록 지시하기 때문입니다. 이 메서드는 사용자가 직접 정의할 수 있는 새 클래스를 포함하여, 시퀀스 객체에 대한 규칙을 따르는 모든 인자와 함께 사용할 수 있습니다. 바이트열과 bytearray 객체에 대해 유사한 메서드가 존재합니다.

예외는 얼마나 빠릅니까?

A try/except block is extremely efficient if no exceptions are raised. Actually catching an exception is expensive. In versions of Python prior to 2.0 it was common to use this idiom:

try:
    value = mydict[key]
except KeyError:
    mydict[key] = getvalue(key)
    value = mydict[key]

이것은 딕셔너리에 거의 항상 키가 있을 것으로 예상했을 때만 의미가 있습니다. 그렇지 않으면, 다음과 같이 코딩했습니다:

if key in mydict:
    value = mydict[key]
else:
    value = mydict[key] = getvalue(key)

이 특정 경우에, value = dict.setdefault(key, getvalue(key))를 사용할 수도 있지만, getvalue() 호출이 모든 경우에 평가되기 때문에 충분히 저렴한 경우에만 사용할 수 있습니다.

파이썬에 switch 나 case 문이 없는 이유는 무엇입니까?

In general, structured switch statements execute one block of code when an expression has a particular value or set of values. Since Python 3.10 one can easily match literal values, or constants within a namespace, with a match ... case statement. An older alternative is a sequence of if... elif... elif... else.

매우 많은 가능성 중에서 선택해야 하는 경우에는, case 값을 호출할 함수에 매핑하는 딕셔너리를 만들 수 있습니다. 예를 들면:

functions = {'a': function_1,
             'b': function_2,
             'c': self.method_1}

func = functions[value]
func()

객체에 대한 메서드 호출의 경우, getattr() 내장 함수를 사용하여 특정 이름을 가진 메서드를 꺼내어 더욱 단순화 할 수 있습니다:

class MyVisitor:
    def visit_a(self):
        ...

    def dispatch(self, value):
        method_name = 'visit_' + str(value)
        method = getattr(self, method_name)
        method()

이 예제의 visit_와 같이 메서드 이름에 접두사를 사용하는 것이 좋습니다. 이러한 접두사가 없으면, 값이 신뢰할 수 없는 소스에서 오는 경우, 공격자가 객체의 모든 메서드를 호출할 수 있습니다.

Imitating switch with fallthrough, as with C’s switch-case-default, is possible, much harder, and less needed.

OS별 스레드 구현에 의존하는 대신 인터프리터에서 스레드를 에뮬레이션할 수 없습니까?

답변 1: 불행히도, 인터프리터는 각 파이썬 스택 프레임에 대해 적어도 하나의 C 스택 프레임을 푸시합니다. 또한, 확장은 거의 임의의 순간에 파이썬으로 콜백 할 수 있습니다. 따라서, 전체 스레드 구현에는 C에 대한 스레드 지원이 필요합니다.

답변 2: 다행히, C 스택을 피하도록 완전히 재설계된 인터프리터 루프가 있는 Stackless Python [https://github.com/stackless-dev/stackless/wiki]이 있습니다.

람다 표현식이 문장을 포함할 수 없는 이유는 무엇입니까?

파이썬의 구문 프레임워크는 표현식 내부에 중첩된 문장을 처리할 수 없기 때문에 파이썬 람다 표현식은 문장을 포함할 수 없습니다. 그러나, 파이썬에서, 이것은 심각한 문제가 아닙니다. 기능을 추가하는 다른 언어의 람다 형식과 달리, 파이썬 람다는 함수를 정의하기에 너무 게으른 경우를 위한 줄임 표기법일 뿐입니다.

Functions are already first class objects in Python, and can be declared in a local scope. Therefore the only advantage of using a lambda instead of a locally defined function is that you don’t need to invent a name for the function – but that’s just a local variable to which the function object (which is exactly the same type of object that a lambda expression yields) is assigned!

파이썬을 기계 코드, C 또는 다른 언어로 컴파일 할 수 있습니까?

Cython [https://cython.org/] compiles a modified version of Python with optional annotations into C extensions. Nuitka [https://nuitka.net/] is an up-and-coming compiler of Python into C++ code, aiming to support the full Python language.

파이썬은 메모리를 어떻게 관리합니까?

파이썬 메모리 관리의 세부 사항은 구현에 따라 다릅니다. 파이썬의 표준 구현인 CPython은 참조 카운팅을 사용하여 액세스할 수 없는 객체를 감지하고, 또 다른 메커니즘을 사용하여 참조 순환을 수집하고, 액세스할 수 없는 순환을 찾고 관련된 객체를 삭제하는 순환 감지 알고리즘을 주기적으로 실행합니다. gc 모듈은 가비지 수집을 수행하고, 디버깅 통계를 얻고, 수거기의 매개 변수를 조정하는 함수를 제공합니다.

Other implementations (such as Jython [https://www.jython.org] or PyPy [https://pypy.org]), however, can rely on a different mechanism such as a full-blown garbage collector. This difference can cause some subtle porting problems if your Python code depends on the behavior of the reference counting implementation.

일부 파이썬 구현에서, 다음 코드(CPython에서는 괜찮습니다)는 아마도 파일 기술자의 소진을 일으킵니다:

for file in very_long_list_of_files:
    f = open(file)
    c = f.read(1)

Indeed, using CPython’s reference counting and destructor scheme, each new assignment to f closes the previous file. With a traditional GC, however, those file objects will only get collected (and closed) at varying and possibly long intervals.

모든 파이썬 구현에서 작동하는 코드를 작성하려면, 명시적으로 파일을 닫거나 with 문을 사용해야 합니다; 다음은 메모리 관리 체계와 관계없이 작동합니다:

for file in very_long_list_of_files:
    with open(file) as f:
        c = f.read(1)

CPython이 더 전통적인 가비지 수거 체계를 사용하지 않는 이유는 무엇입니까?

우선, 이것은 C 표준 기능이 아니라서 이식성이 없습니다. (예, 우리는 Boehm GC 라이브러리에 대해 알고 있습니다. 대부분의 일반 플랫폼용 (그들 전부는 아닙니다) 어셈블러 코드가 있고, 대체로 투명하지만, 완전히 투명하지는 않습니다; 파이썬이 이것으로 작동하도록 하려면 패치가 필요합니다.)

Traditional GC also becomes a problem when Python is embedded into other applications. While in a standalone Python it’s fine to replace the standard malloc() and free() with versions provided by the GC library, an application embedding Python may want to have its own substitute for malloc() and free(), and may not want Python’s. Right now, CPython works with anything that implements malloc() and free() properly.

CPython이 종료될 때 모든 메모리가 해제되지 않는 이유는 무엇입니까?

파이썬 모듈의 전역 이름 공간에서 참조된 객체는 파이썬이 종료될 때 항상 할당 해제되지는 않습니다. 순환 참조가 있으면 발생할 수 있습니다. C 라이브러리에 의해 할당된 해제가 불가능한 특정 메모리도 있습니다 (예를 들어 Purify와 같은 도구는 이에 대해 불평합니다). 그러나, 파이썬은 종료 시 메모리 정리에 적극적이며 모든 단일 객체를 파괴하려고 시도합니다.

할당 해제 시 파이썬이 특정 항목을 삭제하도록 강제하려면 atexit 모듈을 사용하여 해당 삭제를 강제하는 함수를 실행하십시오.

별도의 튜플과 리스트 데이터형이 있는 이유는 무엇입니까?

Lists and tuples, while similar in many respects, are generally used in fundamentally different ways. Tuples can be thought of as being similar to Pascal records or C structs; they’re small collections of related data which may be of different types which are operated on as a group. For example, a Cartesian coordinate is appropriately represented as a tuple of two or three numbers.

Lists, on the other hand, are more like arrays in other languages. They tend to hold a varying number of objects all of which have the same type and which are operated on one-by-one. For example, os.listdir('.') returns a list of strings representing the files in the current directory. Functions which operate on this output would generally not break if you added another file or two to the directory.

튜플은 불변입니다. 즉, 일단 튜플이 만들어지면, 어느 요소도 새 값으로 바꿀 수 없습니다. 리스트는 가변이라서, 언제든지 리스트의 요소를 변경할 수 있습니다. 불변인 요소만 딕셔너리 키로 사용할 수 있어서, 리스트가 아니라 튜플만 키로 사용할 수 있습니다.

CPython에서 리스트는 어떻게 구현됩니까?

CPython의 리스트는 실제로는 가변 길이 배열입니다, Lisp 스타일의 연결 리스트(linked lists)가 아닙니다. 구현은 다른 객체에 대한 참조의 연속적인 배열을 사용하고, 이 배열에 대한 포인터와 배열의 길이를 리스트 헤드 구조체에 유지합니다.

이것은 리스트 인덱싱 a[i]의 비용이 리스트의 크기나 인덱스의 값과 무관한 연산으로 만듭니다.

항목이 추가되거나 삽입되면, 참조 배열의 크기가 조정됩니다. 항목을 반복적으로 추가하는 성능을 향상하기 위해 약간 영리하게 처리합니다; 배열을 확장해야 할 때, 추가 공간이 할당되어 다음 몇 번에는 실제 크기 조정이 필요하지 않습니다.

CPython에서 딕셔너리는 어떻게 구현됩니까?

CPython의 딕셔너리는 크기 조정 가능한 해시 테이블로 구현됩니다. B-트리와 비교해, 대부분의 상황에서 조회(지금까지 가장 흔한 연산) 성능이 향상되고, 구현이 더 간단합니다.

Dictionaries work by computing a hash code for each key stored in the dictionary using the hash() built-in function. The hash code varies widely depending on the key and a per-process seed; for example, 'Python' could hash to -539294296 while 'python', a string that differs by a single bit, could hash to 1142331976. The hash code is then used to calculate a location in an internal array where the value will be stored. Assuming that you’re storing keys that all have different hash values, this means that dictionaries take constant time – O(1), in Big-O notation – to retrieve a key.

딕셔너리 키가 불변이어야 하는 이유는 무엇입니까?

딕셔너리의 해시 테이블 구현은 키값에서 계산된 해시값을 사용하여 키를 찾습니다. 키가 가변 객체이면, 값이 변경될 수 있어서, 해시도 변경될 수 있습니다. 그러나 키 객체를 변경하는 주체는 그것이 딕셔너리 키로 사용되고 있음을 알 수 없기 때문에, 딕셔너리에서 항목을 이동할 수 없습니다. 그런 다음, 딕셔너리에서 같은 객체를 찾으려고 하면 해시값이 다르기 때문에 찾을 수 없습니다. 이전 값을 찾으려고 해도 해당 해시 저장소에서 발견된 객체의 값이 다르기 때문에 역시 찾을 수 없습니다.

딕셔너리를 리스트로 인덱싱하려면, 먼저 리스트를 튜플로 변환하십시오; tuple(L) 함수는 리스트 L과 같은 항목을 가진 튜플을 만듭니다. 튜플은 불변이므로 딕셔너리 키로 사용할 수 있습니다.

제안되었지만 받아들여지지 않은 몇 가지 해법:

주소(객체 ID)로 리스트를 해시 합니다. 같은 값으로 새 리스트를 생성하면 찾을 수 없기 때문에 작동하지 않습니다; 예를 들어:

mydict = {[1, 2]: '12'}
print(mydict[[1, 2]])

는 두 번째 줄에 사용된 [1, 2]의 id가 첫 번째 줄의 것과 다르기 때문에 KeyError 예외가 발생합니다. 즉, 딕셔너리 키는 is가 아니라 ==를 사용하여 비교해야 합니다.

리스트를 키로 사용할 때 사본을 만듭니다. 가변 객체인 리스트가 자신에 대한 참조를 포함할 수 있고, 복사 코드가 무한 루프에 빠질 수 있기 때문에 작동하지 않습니다.

리스트를 키로 허용하지만, 사용자에게 수정하지 않도록 지시합니다. 이것은 잊거나 실수로 리스트를 수정했을 때 프로그램에 추적하기 어려운 버그를 만듭니다. 또한 딕셔너리의 중요한 불변성을 깨뜨립니다; d.keys()의 모든 값은 딕셔너리의 키로 사용할 수 있다.

딕셔너리 키로 사용되면 리스트를 읽기 전용으로 표시합니다. 문제는 그 값을 변경할 수 있는 것은 최상위 객체만이 아니라는 것입니다; 리스트를 포함하는 튜플을 키로 사용할 수 있습니다. 무엇이든 키로 딕셔너리에 입력하면 거기에서 도달할 수 있는 모든 객체를 읽기 전용으로 표시해야 합니다 – 그리고 다시, 자기 참조 객체는 무한 루프를 일으킬 수 있습니다.

There is a trick to get around this if you need to, but use it at your own risk: You can wrap a mutable structure inside a class instance which has both a __eq__() and a __hash__() method. You must then make sure that the hash value for all such wrapper objects that reside in a dictionary (or other hash based structure), remain fixed while the object is in the dictionary (or other structure).

class ListWrapper:
    def __init__(self, the_list):
        self.the_list = the_list

    def __eq__(self, other):
        return self.the_list == other.the_list

    def __hash__(self):
        l = self.the_list
        result = 98767 - len(l)*555
        for i, el in enumerate(l):
            try:
                result = result + (hash(el) % 9999999) * 1001 + i
            except Exception:
                result = (result % 7777777) + i * 333
        return result

해시 계산은 리스트의 일부 멤버가 해시 불가능할 가능성과 산술 오버플로의 가능성으로 인해 복잡함에 유의하십시오.

또한 객체가 딕셔너리에 있는지에 관계없이, 항상 o1 == o2(즉 o1.__eq__(o2) is True)이면 hash(o1) == hash(o2)(즉 o1.__hash__() == o2.__hash__()) 여야 합니다. 이러한 제한 사항을 충족하지 못하면 딕셔너리와 다른 해시 기반 구조가 오작동합니다.

In the case of ListWrapper, whenever the wrapper object is in a dictionary the wrapped list must not change to avoid anomalies. Don’t do this unless you are prepared to think hard about the requirements and the consequences of not meeting them correctly. Consider yourself warned.

list.sort()가 정렬된 리스트를 반환하지 않는 이유는 무엇입니까?

성능이 중요한 상황에서, 단지 정렬하기 위해 리스트를 복사하는 것은 낭비입니다. 따라서, list.sort()는 리스트를 제자리에서 정렬합니다. 이 사실을 상기시키기 위해, 정렬된 리스트를 반환하지 않습니다. 이렇게 하면, 정렬된 복사본이 필요하지만 정렬되지 않은 버전을 유지해야 할 때 실수로 리스트를 덮어쓰지 않도록 합니다.

새 리스트를 반환하려면, 대신 내장 sorted() 함수를 사용하십시오. 이 함수는 제공된 이터러블에서 새 리스트를 만들고, 정렬한 다음 반환합니다. 예를 들어, 정렬된 순서로 딕셔너리의 키를 이터레이트 하는 방법은 다음과 같습니다:

for key in sorted(mydict):
    ...  # do whatever with mydict[key]...

파이썬에서 인터페이스 명세를 어떻게 지정하고 강제합니까?

C++와 Java와 같은 언어에서 제공하는 모듈에 대한 인터페이스 명세는 모듈의 메서드와 함수에 대한 프로토타입을 설명합니다. 많은 사람은 컴파일 타임에 인터페이스 명세를 적용하는 것이 대규모 프로그램을 구축하는 데 도움이 된다고 생각합니다.

파이썬 2.6은 추상 베이스 클래스(ABC)를 정의할 수 있는 abc 모듈을 추가합니다. 그런 다음 isinstance()와 issubclass()를 사용하여 인스턴스나 클래스가 특정 ABC를 구현하는지 확인할 수 있습니다. collections.abc 모듈은 Iterable, Container 및 MutableMapping과 같은 유용한 ABC 집합을 정의합니다.

파이썬의 경우, 구성 요소에 대한 적절한 테스트 규율을 통해 인터페이스 명세의 많은 이점을 얻을 수 있습니다.

모듈에 대한 좋은 테스트 스위트는 회귀 테스트를 제공함과 동시에 모듈 인터페이스 명세와 예제 집합으로 사용할 수 있습니다. 많은 파이썬 모듈은 스크립트로 실행하여 간단한 “자체 테스트”를 제공할 수 있습니다. 복잡한 외부 인터페이스를 사용하는 모듈조차도 외부 인터페이스의 간단한 “스텁(stub)” 에뮬레이션을 사용하여 종종 격리 테스트 할 수 있습니다. doctest와 unittest 모듈 또는 제삼자 테스트 프레임워크를 사용하여 모듈의 모든 코드 줄을 실행하는 포괄적인 테스트 스위트를 구축할 수 있습니다.

An appropriate testing discipline can help build large complex applications in Python as well as having interface specifications would. In fact, it can be better because an interface specification cannot test certain properties of a program. For example, the list.append() method is expected to add new elements to the end of some internal list; an interface specification cannot test that your list.append() implementation will actually do this correctly, but it’s trivial to check this property in a test suite.

테스트 스위트를 작성하는 것은 매우 도움이 되며, 쉽게 테스트 할 수 있도록 코드를 설계할 수 있습니다. 점점 더 많이 사용되는 기술인 테스트 기반 개발(test-driven development)에서는, 실제 코드를 작성하기 전에 먼저 테스트 스위트의 일부를 작성해야 합니다. 물론 파이썬은 여러분이 지저분해지거나 테스트 케이스를 전혀 작성하지 않을 수 있도록 허락합니다.

goto가 없는 이유는 무엇입니까?

In the 1970s people realized that unrestricted goto could lead to messy “spaghetti” code that was hard to understand and revise. In a high-level language, it is also unneeded as long as there are ways to branch (in Python, with if statements and or, and, and if/else expressions) and loop (with while and for statements, possibly containing continue and break).

One can also use exceptions to provide a “structured goto” that works even across function calls. Many feel that exceptions can conveniently emulate all reasonable uses of the go or goto constructs of C, Fortran, and other languages. For example:

class label(Exception): pass  # declare a label

try:
    ...
    if condition: raise label()  # goto label
    ...
except label:  # where to goto
    pass
...

This doesn’t allow you to jump into the middle of a loop, but that’s usually considered an abuse of goto anyway. Use sparingly.

날 문자열(r-strings)이 역 슬래시로 끝날 수 없는 이유는 무엇입니까?

더 정확하게는, 홀수 개의 역 슬래시로 끝날 수 없습니다: 끝의 쌍이 없는 역 슬래시는 닫는 따옴표 문자를 이스케이프 하여, 끝나지 않은 문자열을 남깁니다.

날 문자열은 자체 역 슬래시 이스케이프 처리를 수행하려는 프로세서(주로 정규식 엔진)에 대한 입력을 쉽게 만들 수 있도록 설계되었습니다. 이러한 프로세서는 일치하지 않는 후행 역 슬래시를 에러로 간주하므로, 날 문자열은 이를 허용하지 않습니다. 그 대가로, 역 슬래시로 이스케이프 하여 문자열 따옴표 문자를 전달할 수 있습니다. 이 규칙은 r-문자열이 의도된 목적으로 사용될 때 잘 작동합니다.

윈도우 경로명을 빌드하려는 경우, 모든 윈도우 시스템 호출은 슬래시도 허용함에 유의하십시오:

f = open("/mydir/file.txt")  # works fine!

DOS 명령에 대한 경로명을 빌드하려는 경우, 예를 들어, 다음 중 하나를 시도하십시오

dir = r"\this\is\my\dos\dir" "\\"
dir = r"\this\is\my\dos\dir\ "[:-1]
dir = "\\this\\is\\my\\dos\\dir\\"

왜 파이썬에는 어트리뷰트 대입을 위한 “with” 문이 없습니까?

Python has a with statement that wraps the execution of a block, calling code on the entrance and exit from the block. Some languages have a construct that looks like this:

with obj:
    a = 1               # equivalent to obj.a = 1
    total = total + 1   # obj.total = obj.total + 1

파이썬에서는, 이러한 구조가 모호해집니다.

오브젝트 파스칼, 델파이 및 C++와 같은 다른 언어는 정적 형을 사용하므로, 어떤 멤버가 대입되고 있는지 명확하게 알 수 있습니다. 이것이 정적 타이핑의 요점입니다 – 컴파일러는 항상 컴파일 시점에 모든 변수의 스코프를 알고 있습니다.

파이썬은 동적 형을 사용합니다. 실행 시간에 어떤 어트리뷰트가 참조되는지 미리 알 수 없습니다. 멤버 어트리뷰트는 실행 중에 객체에 추가하거나 제거할 수 있습니다. 이로 인해 단순한 읽기만으로는 어떤 어트리뷰트가 참조되는 중인지 알 수 없습니다: 지역 변수, 전역 변수 또는 멤버 어트리뷰트?

예를 들어, 다음과 같은 불완전한 스니펫을 보십시오:

def foo(a):
    with a:
        print(x)

The snippet assumes that a must have a member attribute called x. However, there is nothing in Python that tells the interpreter this. What should happen if a is, let us say, an integer? If there is a global variable named x, will it be used inside the with block? As you see, the dynamic nature of Python makes such choices much harder.

The primary benefit of with and similar language features (reduction of code volume) can, however, easily be achieved in Python by assignment. Instead of:

function(args).mydict[index][index].a = 21
function(args).mydict[index][index].b = 42
function(args).mydict[index][index].c = 63

이렇게 작성하십시오:

ref = function(args).mydict[index][index]
ref.a = 21
ref.b = 42
ref.c = 63

이름 연결은 파이썬에서 실행 시간에 결정되는데, 두 번째 버전은 확인을 한 번만 수행하면 되므로 실행 속도를 높이는 부작용도 있습니다.

Similar proposals that would introduce syntax to further reduce code volume, such as using a ‘leading dot’, have been rejected in favour of explicitness (see https://mail.python.org/pipermail/python-ideas/2016-May/040070.html).

Why don’t generators support the with statement?

For technical reasons, a generator used directly as a context manager would not work correctly. When, as is most common, a generator is used as an iterator run to completion, no closing is needed. When it is, wrap it as contextlib.closing(generator) in the with statement.

if/while/def/class 문에 콜론이 필요한 이유는 무엇입니까?

콜론은 주로 가독성을 높이기 위해 필요합니다 (실험적 ABC 언어의 결과 중 하나입니다). 이걸 고려해보십시오:

if a == b
    print(a)

와

if a == b:
    print(a)

두 번째 것이 어떻게 약간 더 읽기 쉬운지 주목하십시오. 이 FAQ 답변에서 콜론이 어떻게 예제를 시작하는지도 주목하십시오; 영어의 표준 사용법입니다.

또 다른 사소한 이유는 콜론이 구문 강조 표시가 있는 편집기를 도와준다는 것입니다: 들여쓰기를 늘려야 하는 때를 결정하기 위해, 프로그램 텍스트를 더 정교하게 구문 분석하는 대신 콜론을 찾을 수 있습니다.

파이썬은 왜 리스트와 튜플 끝에 쉼표를 허용합니까?

파이썬은 리스트, 튜플 및 딕셔너리 끝에 후행 쉼표를 추가할 수 있도록 합니다:

[1, 2, 3,]
('a', 'b', 'c',)
d = {
    "A": [1, 5],
    "B": [6, 7],  # last trailing comma is optional but good style
}

이를 허용하는 데에는 몇 가지 이유가 있습니다.

리스트, 튜플 또는 딕셔너리에 대한 리터럴 값이 여러 줄에 걸쳐 있는 경우, 이전 줄에 쉼표를 추가할 필요가 없기 때문에 요소를 추가하기가 더 쉽습니다. 문법 에러를 만들지 않고 줄을 재정렬할 수도 있습니다.

실수로 쉼표를 누락하면 진단하기 어려운 에러가 발생할 수 있습니다. 예를 들면:

x = [
  "fee",
  "fie"
  "foo",
  "fum"
]

이 리스트에는 네 개의 요소가 있는 것처럼 보이지만, 실제로는 세 가지 요소만 있습니다: “fee”, “fiefoo” 및 “fum”. 항상 쉼표를 추가하면 이러한 에러 원인을 피할 수 있습니다.

후행 쉼표를 허용하면 프로그래밍적인 코드 생성이 더 쉬워질 수도 있습니다.

라이브러리와 확장 FAQ

목차

라이브러리와 확장 FAQ

일반 라이브러리 관련 질문

작업 X를 수행할 모듈이나 응용 프로그램을 어떻게 찾습니까?

math.py (socket.py, regex.py 등) 소스 파일은 어디에 있습니까?

유닉스에서 파이썬 스크립트를 실행 파일로 만들려면 어떻게 해야 합니까?

파이썬 용 curses/termcap 패키지가 있습니까?

파이썬에 C의 onexit()와 동등한 것이 있습니까?

시그널 처리기가 작동하지 않는 이유는 무엇입니까?

일반적인 작업

파이썬 프로그램이나 컴포넌트를 어떻게 테스트합니까?

독스트링으로 설명서를 어떻게 만듭니까?

한 번에 하나의 키 입력을 받는 방법은 무엇입니까?

스레드

스레드를 사용하여 어떻게 프로그래밍합니까?

제 스레드가 아무것도 실행되지 않는 것 같습니다: 왜 그런가요?

여러 작업자 스레드 간에 작업을 어떻게 배달합니까?

어떤 종류의 전역 값 변경이 스레드 안전합니까?

전역 인터프리터 록을 제거할 수 없습니까?

입력과 출력

파일을 어떻게 삭제합니까? (그리고 다른 파일 질문들…)

파일을 어떻게 복사합니까?

바이너리 데이터를 읽는 (또는 쓰는) 방법은 무엇입니까?

os.popen()으로 만든 파이프에서 os.read()를 사용할 수 없는 것처럼 보입니다; 왜입니까?

직렬 (RS232) 포트에 어떻게 액세스합니까?

왜 sys.stdout(stdin, stderr)을 닫아도 닫히지 않습니까?

네트워크/인터넷 프로그래밍

파이썬에는 어떤 WWW 도구가 있습니까?

HTML 생성을 위해 어떤 모듈을 사용해야 합니까?

파이썬 스크립트에서 메일을 보내려면 어떻게 해야 합니까?

소켓의 connect() 메서드에서 블로킹을 피하려면 어떻게 해야 합니까?

데이터베이스

파이썬에 데이터베이스 패키지에 대한 인터페이스가 있습니까?

파이썬에서 영속 객체를 어떻게 구현합니까?

수학과 숫자

파이썬에서 난수를 어떻게 생성합니까?

일반 라이브러리 관련 질문

작업 X를 수행할 모듈이나 응용 프로그램을 어떻게 찾습니까?

관련 표준 라이브러리 모듈이 있는지 라이브러리 레퍼런스를 확인하십시오. (결국에는 표준 라이브러리에 있는 내용을 배우고 이 단계를 건너뛸 수 있게 됩니다.)

For third-party packages, search the Python Package Index [https://pypi.org] or try Google [https://www.google.com] or another web search engine. Searching for “Python” plus a keyword or two for your topic of interest will usually find something helpful.

math.py (socket.py, regex.py 등) 소스 파일은 어디에 있습니까?

모듈의 소스 파일을 찾을 수 없으면 C, C++ 또는 기타 컴파일된 언어로 구현된 내장이나 동적으로 로드된 모듈일 수 있습니다. 이 경우 소스 파일이 없거나 C 소스 디렉터리(파이썬 경로에 없는)의 mathmodule.c와 같은 파일일 수 있습니다.

파이썬에는 (적어도) 세 가지 종류의 모듈이 있습니다:

파이썬으로 작성된 모듈 (.py);

C로 작성되고 동적으로 로드되는 모듈 (.dll, .pyd, .so, .sl 등);

C로 작성되고 인터프리터와 링크된 모듈; 이 목록을 얻으려면, 다음을 입력하십시오:

import sys
print(sys.builtin_module_names)

유닉스에서 파이썬 스크립트를 실행 파일로 만들려면 어떻게 해야 합니까?

두 가지를 해야 합니다: 스크립트 파일의 모드는 실행 가능해야 하고 첫 번째 줄은 #!로 시작하고 그 뒤에 파이썬 인터프리터 경로가 있어야 합니다.

첫 번째는 chmod +x scriptfile이나 아마도 chmod 755 scriptfile을 실행하여 수행됩니다.

두 번째는 여러 가지 방법으로 수행 할 수 있습니다. 가장 간단한 방법은 다음과 같은 줄을

#!/usr/local/bin/python

파이썬 인터프리터가 플랫폼에 설치된 경로 이름을 사용하여 파일의 첫 번째 줄로 작성하는 것입니다.

스크립트가 파이썬 인터프리터가 있는 위치와 독립적으로 되도록 하려면, env 프로그램을 사용할 수 있습니다. 파이썬 인터프리터가 사용자 PATH의 디렉터리에 있다고 가정하면, 거의 모든 유닉스 변형이 다음을 지원합니다:

#!/usr/bin/env python

이것을 CGI 스크립트에 적용하지 마십시오. CGI 스크립트의 PATH 변수는 종종 최소한이라서, 인터프리터의 실제 절대 경로명을 사용해야 합니다.

때때로, 사용자 환경이 가득 차서 /usr/bin/env 프로그램이 실패합니다; 또는 env 프로그램이 아예 없습니다. 이 경우, 다음과 같은 핵을 시도할 수 있습니다 (Alex Rezinsky의 기법입니다):

#! /bin/sh
""":"
exec python $0 ${1+"$@"}
"""

작은 단점은 이것이 스크립트의 __doc__ 문자열을 정의한다는 것입니다. 그러나, 다음을 추가하여 문제를 해결할 수 있습니다

__doc__ = """...Whatever..."""

파이썬 용 curses/termcap 패키지가 있습니까?

유닉스 변형의 경우: 표준 파이썬 소스 배포판은 기본적으로 컴파일되지는 않지만, Modules [https://github.com/python/cpython/tree/main/Modules] 서브 디렉터리에 curses 모듈을 포함합니다. (윈도우 배포판에서는 사용할 수 없습니다 – 윈도우용 curses 모듈은 없습니다.)

curses 모듈은 기본 curses 기능뿐만 아니라 색상, 대체 문자 집합 지원, 패드 및 마우스 지원과 같은 ncurses와 SYSV curses의 많은 추가 기능을 지원합니다. 이는 모듈이 BSD curses만 있는 운영 체제와 호환되지 않음을 뜻하지만, 현재 유지 보수되는 OS들은 어느 것도 이 범주에 속하지 않는 것 같습니다.

파이썬에 C의 onexit()와 동등한 것이 있습니까?

The atexit module provides a register function that is similar to C’s onexit().

시그널 처리기가 작동하지 않는 이유는 무엇입니까?

가장 흔한 문제점은 시그널 처리기가 잘못된 인자 목록으로 선언되는 것입니다. 이렇게 호출됩니다

handler(signum, frame)

따라서 두 개의 매개 변수로 선언해야 합니다:

def handler(signum, frame):
    ...

일반적인 작업

파이썬 프로그램이나 컴포넌트를 어떻게 테스트합니까?

파이썬에는 두 가지 테스트 프레임워크가 있습니다. doctest 모듈은 모듈의 독스트링에 있는 예제를 찾고 실행한 후, 출력을 독스트링에 제공된 예상 출력과 비교합니다.

unittest 모듈은 Java와 Smalltalk 테스트 프레임 워크에서 모델링 된 더 멋진 테스트 프레임워크입니다.

테스트를 더 쉽게 하려면, 여러분의 프로그램에 좋은 모듈식 디자인을 사용해야 합니다. 프로그램은 거의 모든 기능을 함수나 클래스 메서드로 캡슐화해야 합니다 – 그리고 이는 때로 프로그램을 더 빠르게 실행하는 놀라운 효과가 있습니다 (지역 변수 액세스가 전역 액세스보다 빠르기 때문에). 또한 프로그램은 전역 변수를 변경하는 것에 의존하지 않아야 합니다, 이렇게 하면 테스트하기가 훨씬 어렵기 때문입니다.

프로그램의 “전역 메인 논리”는 다음과 같은 코드를

if __name__ == "__main__":
    main_logic()

프로그램의 메인 모듈 하단에 넣는 것처럼 간단할 수 있습니다.

일단 프로그램이 다루기 쉬운 함수와 클래스 동작의 모음으로 구성되면, 이 동작을 검사하는 테스트 함수를 작성해야 합니다. 일련의 테스트를 자동화하는 테스트 스위트는 각 모듈과 연관될 수 있습니다. 이것은 많은 작업처럼 들리지만, 파이썬이 아주 간결하고 유연하기 때문에 놀랍도록 쉽습니다. “프로덕션 코드”와 함께 테스트 함수를 작성하여 코딩을 훨씬 더 즐겁고 재미있게 만들 수 있습니다. 버그를 쉽게 찾고 결함을 조기에 발견할 수 있기 때문입니다.

프로그램의 메인 모듈이 아닌 “지원 모듈”에는 모듈의 자체 테스트가 포함될 수 있습니다.

if __name__ == "__main__":
    self_test()

복잡한 외부 인터페이스와 상호 작용하는 프로그램조차도 파이썬으로 구현된 “가짜” 인터페이스를 사용하여 외부 인터페이스를 사용할 수 없을 때 테스트할 수 있습니다.

독스트링으로 설명서를 어떻게 만듭니까?

The pydoc module can create HTML from the doc strings in your Python source code. An alternative for creating API documentation purely from docstrings is epydoc [https://epydoc.sourceforge.net/]. Sphinx [https://www.sphinx-doc.org] can also include docstring content.

한 번에 하나의 키 입력을 받는 방법은 무엇입니까?

유닉스 변형에는 몇 가지 해결책이 있습니다. curses를 사용하여 이 작업을 수행하는 것은 간단하지만, curses는 배우기에 상당히 큰 모듈입니다.

스레드

스레드를 사용하여 어떻게 프로그래밍합니까?

_thread 모듈이 아닌 threading 모듈을 사용하십시오. threading 모듈은 _thread 모듈이 제공하는 저수준 프리미티브 위에 편리한 추상화를 구축합니다.

제 스레드가 아무것도 실행되지 않는 것 같습니다: 왜 그런가요?

메인 스레드가 종료되자마자, 모든 스레드가 죽습니다. 메인 스레드가 너무 빨리 실행되어, 스레드가 작업을 수행할 시간이 없습니다.

간단한 수정은 프로그램 끝에 모든 스레드가 완료될 만큼 충분히 긴 휴면을 추가하는 것입니다:

import threading, time

def thread_task(name, n):
    for i in range(n):
        print(name, i)

for i in range(10):
    T = threading.Thread(target=thread_task, args=(str(i), i))
    T.start()

time.sleep(10)  # <---------------------------!

그러나 이제 (많은 플랫폼에서) 스레드는 병렬로 실행되지 않고, 한 번에 하나씩 순차적으로 실행되는 것처럼 보입니다! 그 이유는 OS 스레드 스케줄러가 이전 스레드가 블록 될 때까지 새 스레드를 시작하지 않기 때문입니다.

간단한 수정은 실행 함수의 시작 부분에 작은 휴면을 추가하는 것입니다:

def thread_task(name, n):
    time.sleep(0.001)  # <--------------------!
    for i in range(n):
        print(name, i)

for i in range(10):
    T = threading.Thread(target=thread_task, args=(str(i), i))
    T.start()

time.sleep(10)

time.sleep()을 위한 좋은 지연 값을 추측하는 대신, 일종의 세마포어 메커니즘을 사용하는 것이 좋습니다. 한 가지 아이디어는 queue 모듈을 사용하여 큐 객체를 만들고, 각 스레드가 완료될 때 큐에 토큰을 추가하게 하고, 메인 스레드가 스레드 수 만큼의 토큰을 읽도록 하는 것입니다.

여러 작업자 스레드 간에 작업을 어떻게 배달합니까?

가장 쉬운 방법은 concurrent.futures 모듈, 특히 ThreadPoolExecutor 클래스를 사용하는 것입니다.

또는, 디스패치 알고리즘을 세밀하게 제어하려면, 직접 논리를 작성할 수 있습니다. queue 모듈을 사용하여 작업 목록을 포함하는 큐를 만드십시오. Queue 클래스는 객체 목록을 유지하고 큐에 항목을 추가하는 .put(obj) 메서드와 이를 반환하는 .get() 메서드를 갖습니다. 클래스는 각 작업이 정확히 한 번만 전달되도록 하는 데 필요한 록을 관리합니다.

간단한 예를 들면 다음과 같습니다:

import threading, queue, time

# The worker thread gets jobs off the queue.  When the queue is empty, it
# assumes there will be no more work and exits.
# (Realistically workers will run until terminated.)
def worker():
    print('Running worker')
    time.sleep(0.1)
    while True:
        try:
            arg = q.get(block=False)
        except queue.Empty:
            print('Worker', threading.current_thread(), end=' ')
            print('queue empty')
            break
        else:
            print('Worker', threading.current_thread(), end=' ')
            print('running with argument', arg)
            time.sleep(0.5)

# Create queue
q = queue.Queue()

# Start a pool of 5 workers
for i in range(5):
    t = threading.Thread(target=worker, name='worker %i' % (i+1))
    t.start()

# Begin adding work to the queue
for i in range(50):
    q.put(i)

# Give threads time to run
print('Main thread sleeping')
time.sleep(5)

실행하면 다음과 같은 출력이 생성됩니다:

Running worker
Running worker
Running worker
Running worker
Running worker
Main thread sleeping
Worker <Thread(worker 1, started 130283832797456)> running with argument 0
Worker <Thread(worker 2, started 130283824404752)> running with argument 1
Worker <Thread(worker 3, started 130283816012048)> running with argument 2
Worker <Thread(worker 4, started 130283807619344)> running with argument 3
Worker <Thread(worker 5, started 130283799226640)> running with argument 4
Worker <Thread(worker 1, started 130283832797456)> running with argument 5
...

자세한 내용은 모듈 설명서를 참조하십시오. Queue 클래스는 기능이 풍부한 인터페이스를 제공합니다.

어떤 종류의 전역 값 변경이 스레드 안전합니까?

내부적으로 전역 인터프리터 록(GIL)이 사용되어 한 번에 하나의 스레드 만 파이썬 VM에서 실행되도록 합니다. 일반적으로, 파이썬은 바이트 코드 명령어들 사이에서만 스레드 간 전환을 제공합니다; sys.setswitchinterval()을 통해 얼마나 자주 전환할지를 설정할 수 있습니다. 따라서 각 바이트 코드 명령어와 각 명령어에서 도달하는 모든 C 구현 코드는 파이썬 프로그램의 관점에서 원자 적입니다.

이론적으로, 이것은 정확하게 따지기 위해서는 PVM 바이트 코드 구현에 대한 정확한 이해가 필요하다는 것을 의미합니다. 경험적으로는, 이것은 “원자 적으로 보이는” 내장 데이터형(정수, 리스트, 딕셔너리 등)의 공유 변수에 대한 조작이 실제로 원자 적임을 의미합니다.

예를 들어, 다음 연산은 모두 원자 적입니다 (L, L1, L2는 리스트, D, D1, D2는 딕셔너리, x, y는 객체, i, j는 정수입니다):

L.append(x)
L1.extend(L2)
x = L[i]
x = L.pop()
L1[i:j] = L2
L.sort()
x = y
x.field = y
D[x] = y
D1.update(D2)
D.keys()

이것들은 아닙니다:

i = i+1
L.append(L[-1])
L[i] = L[j]
D[x] = D[x] + 1

Operations that replace other objects may invoke those other objects’ __del__() method when their reference count reaches zero, and that can affect things. This is especially true for the mass updates to dictionaries and lists. When in doubt, use a mutex!

전역 인터프리터 록을 제거할 수 없습니까?

전역 인터프리터 록(GIL)은 종종 하이 엔드 다중 프로세서 서버 기계에 파이썬을 배치하는 데 방해가 된다고 여겨집니다, (거의) 모든 파이썬 코드가 GIL을 잡고 있는 동안에만 실행하려고 해서, 다중 스레드 파이썬 프로그램이 사실상 오직 하나의 CPU만 사용하기 때문입니다.

With the approval of PEP 703 [https://peps.python.org/pep-0703/] work is now underway to remove the GIL from the CPython implementation of Python. Initially it will be implemented as an optional compiler flag when building the interpreter, and so separate builds will be available with and without the GIL. Long-term, the hope is to settle on a single build, once the performance implications of removing the GIL are fully understood. Python 3.13 is likely to be the first release containing this work, although it may not be completely functional in this release.

The current work to remove the GIL is based on a fork of Python 3.9 with the GIL removed [https://github.com/colesbury/nogil] by Sam Gross. Prior to that, in the days of Python 1.5, Greg Stein actually implemented a comprehensive patch set (the “free threading” patches) that removed the GIL and replaced it with fine-grained locking. Adam Olsen did a similar experiment in his python-safethread [https://code.google.com/archive/p/python-safethread] project. Unfortunately, both of these earlier experiments exhibited a sharp drop in single-thread performance (at least 30% slower), due to the amount of fine-grained locking necessary to compensate for the removal of the GIL. The Python 3.9 fork is the first attempt at removing the GIL with an acceptable performance impact.

The presence of the GIL in current Python releases doesn’t mean that you can’t make good use of Python on multi-CPU machines! You just have to be creative with dividing the work up between multiple processes rather than multiple threads. The ProcessPoolExecutor class in the new concurrent.futures module provides an easy way of doing so; the multiprocessing module provides a lower-level API in case you want more control over dispatching of tasks.

C 확장을 신중하게 사용하는 것도 도움이 됩니다; C 확장을 사용하여 시간이 오래 걸리는 작업을 수행하면, 확장은 실행 스레드가 C 코드에 있는 동안 GIL을 해제하고 다른 스레드가 어떤 작업을 수행할 수 있도록 할 수 있습니다. zlib와 hashlib와 같은 일부 표준 라이브러리 모듈은 이미 이렇게 합니다.

An alternative approach to reducing the impact of the GIL is to make the GIL a per-interpreter-state lock rather than truly global. This was first implemented in Python 3.12 and is available in the C API. A Python interface to it is expected in Python 3.13. The main limitation to it at the moment is likely to be 3rd party extension modules, since these must be written with multiple interpreters in mind in order to be usable, so many older extension modules will not be usable.

입력과 출력

파일을 어떻게 삭제합니까? (그리고 다른 파일 질문들…)

os.remove(filename)이나 os.unlink(filename)을 사용하십시오; 설명서는 os 모듈을 참조하십시오. 두 함수는 동일합니다; unlink()는 단순히 이 함수에 대한 유닉스 시스템 호출의 이름입니다.

디렉터리를 제거하려면, os.rmdir()을 사용하십시오; 만들려면 os.mkdir()을 사용하십시오. os.makedirs(path)는 존재하지 않는 path의 중간 디렉터리를 만듭니다. os.removedirs(path)는 비어있는 한, 중간 디렉터리를 제거합니다; 전체 디렉터리 트리와 그 내용을 삭제하려면 shutil.rmtree()를 사용하십시오.

파일 이름을 바꾸려면 os.rename(old_path, new_path)를 사용하십시오.

파일을 자르려면, f = open(filename, "rb+")를 사용하여 열고 f.truncate(offset)을 사용하십시오; offset의 기본값은 현재 탐색(seek) 위치입니다. os.open()으로 열린 파일의 경우 os.ftruncate(fd, offset)도 있습니다. 여기서 fd는 파일 기술자(작은 정수)입니다.

shutil 모듈에도 copyfile(), copytree() 및 rmtree()를 포함한 파일에서 작동하는 많은 함수가 포함되어 있습니다.

파일을 어떻게 복사합니까?

The shutil module contains a copyfile() function. Note that on Windows NTFS volumes, it does not copy alternate data streams [https://en.wikipedia.org/wiki/NTFS#Alternate_data_stream_(ADS)] nor resource forks [https://en.wikipedia.org/wiki/Resource_fork] on macOS HFS+ volumes, though both are now rarely used. It also doesn’t copy file permissions and metadata, though using shutil.copy2() instead will preserve most (though not all) of it.

바이너리 데이터를 읽는 (또는 쓰는) 방법은 무엇입니까?

복잡한 바이너리 데이터 형식을 읽거나 쓰려면, struct 모듈을 사용하는 것이 가장 좋습니다. 바이너리 데이터(보통 숫자)를 포함하는 문자열을 취해서 파이썬 객체로 변환할 수 있도록 합니다; 그리고 그 반대도 가능합니다.

예를 들어, 다음 코드는 파일에서 빅 엔디안 형식의 두 개의 2-바이트 정수와 하나의 4-바이트 정수를 읽습니다:

import struct

with open(filename, "rb") as f:
    s = f.read(8)
    x, y, z = struct.unpack(">hhl", s)

포맷 문자열의 ‘>’는 빅 엔디안 데이터를 강제합니다; 문자 ‘h’는 하나의 “짧은(short) 정수”(2바이트)를 읽고, ‘l’은 문자열에서 하나의 “긴(long) 정수”(4바이트)를 읽습니다.

더욱 규칙적인 데이터(예를 들어 int나 float의 동종 리스트)의 경우, array 모듈을 사용할 수도 있습니다.

참고

바이너리 데이터를 읽고 쓰려면, 바이너리 모드로 파일을 열어야 합니다 (여기서는, "rb"를 open()으로 전달합니다). 대신 "r"(기본값)을 사용하면, 파일이 텍스트 모드로 열리고 f.read()는 bytes 객체 대신 str 객체를 반환합니다.

os.popen()으로 만든 파이프에서 os.read()를 사용할 수 없는 것처럼 보입니다; 왜입니까?

os.read()는 열린 파일을 나타내는 작은 정수인 파일 기술자를 취하는 저수준 함수입니다. os.popen()은 내장 open() 함수에서 반환하는 것과 같은 형의 고수준 파일 객체를 만듭니다. 따라서, os.popen()으로 만들어진 파이프 p에서 n 바이트를 읽으려면, p.read(n)을 사용해야 합니다.

직렬 (RS232) 포트에 어떻게 액세스합니까?

For Win32, OSX, Linux, BSD, Jython, IronPython:

pyserial [https://pypi.org/project/pyserial/]

유닉스의 경우, Mitch Chapman의 유즈넷 게시물을 참조하십시오:

https://groups.google.com/groups?selm=34A04430.CF9@ohioee.com

왜 sys.stdout(stdin, stderr)을 닫아도 닫히지 않습니까?

파이썬 파일 객체는 저수준 C 파일 기술자의 고수준 추상화 계층입니다.

내장 open() 함수를 통해 파이썬에서 만드는 대부분 파일 객체의 경우, f.close()는 파이썬 파일 객체를 파이썬의 관점에서 닫은 것으로 표시하고 하부 C 파일 기술자를 닫도록 합니다. 이것은 f가 가비지가 될 때 f의 파괴자에서 자동으로 일어나기도 합니다.

그러나 stdin, stdout 및 stderr은 파이썬에서 특별하게 처리되는데, C 역시 이들에게 특수한 상태를 부여하기 때문입니다. sys.stdout.close()를 실행하면 파이썬 수준 파일 객체가 닫힌 것으로 표시되지만, 연관된 C 파일 기술자를 닫지 않습니다.

이 세 가지 중 하나에 대한 하부 C 파일 기술자를 닫으려면, 먼저 이것이 정말로 여러분이 하고 싶은 것인지 확인해야 합니다 (예를 들어, I/O를 수행하려는 확장 모듈이 혼동할 수 있습니다). 그렇다면, os.close()를 사용하십시오:

os.close(stdin.fileno())
os.close(stdout.fileno())
os.close(stderr.fileno())

또는 숫자 상수 0, 1 및 2를 각각 사용할 수 있습니다.

네트워크/인터넷 프로그래밍

파이썬에는 어떤 WWW 도구가 있습니까?

라이브러리 레퍼런스 매뉴얼의 인터넷 프로토콜과 지원과 인터넷 데이터 처리 장을 참조하십시오. 파이썬에는 서버 측과 클라이언트 측 웹 시스템을 구축하는 데 도움이 되는 많은 모듈이 있습니다.

사용 가능한 프레임워크 요약은 Paul Boddie가 https://wiki.python.org/moin/WebProgramming에서 유지 관리합니다.

HTML 생성을 위해 어떤 모듈을 사용해야 합니까?

Web Programming wiki page [https://wiki.python.org/moin/WebProgramming]에서 유용한 링크 모음을 찾을 수 있습니다.

파이썬 스크립트에서 메일을 보내려면 어떻게 해야 합니까?

표준 라이브러리 모듈 smtplib를 사용하십시오.

다음은 이를 사용하는 매우 간단한 대화식 메일 발신기입니다. 이 방법은 SMTP 리스너를 지원하는 모든 호스트에서 작동합니다.

import sys, smtplib

fromaddr = input("From: ")
toaddrs  = input("To: ").split(',')
print("Enter message, end with ^D:")
msg = ''
while True:
    line = sys.stdin.readline()
    if not line:
        break
    msg += line

# The actual mail send
server = smtplib.SMTP('localhost')
server.sendmail(fromaddr, toaddrs, msg)
server.quit()

유닉스 전용 대안은 sendmail을 사용합니다. sendmail 프로그램의 위치는 시스템마다 다릅니다; 때로는 /usr/lib/sendmail, 때로는 /usr/sbin/sendmail. sendmail 매뉴얼 페이지가 도움이 될 것입니다. 샘플 코드는 다음과 같습니다:

import os

SENDMAIL = "/usr/sbin/sendmail"  # sendmail location
p = os.popen("%s -t -i" % SENDMAIL, "w")
p.write("To: receiver@example.com\n")
p.write("Subject: test\n")
p.write("\n")  # blank line separating headers from body
p.write("Some text\n")
p.write("some more text\n")
sts = p.close()
if sts != 0:
    print("Sendmail exit status", sts)

소켓의 connect() 메서드에서 블로킹을 피하려면 어떻게 해야 합니까?

select 모듈이 소켓의 비동기 I/O를 지원하는 데 흔히 사용됩니다.

To prevent the TCP connect from blocking, you can set the socket to non-blocking mode. Then when you do the connect(), you will either connect immediately (unlikely) or get an exception that contains the error number as .errno. errno.EINPROGRESS indicates that the connection is in progress, but hasn’t finished yet. Different OSes will return different values, so you’re going to have to check what’s returned on your system.

You can use the connect_ex() method to avoid creating an exception. It will just return the errno value. To poll, you can call connect_ex() again later – 0 or errno.EISCONN indicate that you’re connected – or you can pass this socket to select.select() to check if it’s writable.

참고

The asyncio module provides a general purpose single-threaded and concurrent asynchronous library, which can be used for writing non-blocking network code. The third-party Twisted [https://twisted.org/] library is a popular and feature-rich alternative.

데이터베이스

파이썬에 데이터베이스 패키지에 대한 인터페이스가 있습니까?

예.

DBM과 GDBM같은 디스크 기반 해시에 대한 인터페이스도 표준 파이썬에 포함되어 있습니다. 경량 디스크 기반 관계형 데이터베이스를 제공하는 sqlite3 모듈도 있습니다.

대부분 관계형 데이터베이스에 대한 지원이 제공됩니다. 자세한 내용은 DatabaseProgramming wiki page [https://wiki.python.org/moin/DatabaseProgramming]를 참조하십시오.

파이썬에서 영속 객체를 어떻게 구현합니까?

pickle 라이브러리 모듈은 이것을 매우 일반적인 방식으로 해결하고 (여전히 열린 파일, 소켓 또는 창과 같은 것을 저장할 수는 없지만), shelve 라이브러리 모듈은 pickle과 (g)dbm을 사용하여 임의의 파이썬 객체를 포함하는 영속적(persistent) 매핑을 만듭니다.

수학과 숫자

파이썬에서 난수를 어떻게 생성합니까?

표준 모듈 random은 난수 생성기를 구현합니다. 사용법은 간단합니다:

import random
random.random()

This returns a random floating-point number in the range [0, 1).

이 모듈에는 다른 많은 특수 생성기가 있습니다, 가령:

randrange(a, b)는 [a, b) 범위의 정수를 선택합니다.

uniform(a, b) chooses a floating-point number in the range [a, b).

normalvariate(mean, sdev)는 정규 (가우시안) 분포를 샘플링합니다.

일부 고수준 함수는 시퀀스에서 직접 작동합니다, 가령:

choice(S)는 주어진 시퀀스에서 무작위 요소 하나를 선택합니다.

shuffle(L)은 리스트를 제자리에서 섞습니다, 즉 무작위로 순서를 바꿉니다.

독립적인 여러 개의 난수 생성기를 만들기 위해 인스턴스 화 할 수 있는 Random 클래스도 있습니다.

확장/내장 FAQ

목차

확장/내장 FAQ

C로 나만의 함수를 만들 수 있습니까?

C++로 나만의 함수를 만들 수 있습니까?

C를 쓰는 것은 어렵습니다; 대안이 있습니까?

C에서 임의의 파이썬 문장을 어떻게 실행할 수 있습니까?

C에서 임의의 파이썬 표현식을 어떻게 평가할 수 있습니까?

파이썬 객체에서 C값을 어떻게 추출합니까?

Py_BuildValue()를 사용하여 임의 길이의 튜플을 만드는 방법은 무엇입니까?

C에서 객체의 메서드를 어떻게 호출합니까?

PyErr_Print()의 출력(또는 stdout/stderr로 인쇄되는 모든 것)을 어떻게 잡습니까?

C에서 파이썬으로 작성된 모듈에 어떻게 액세스합니까?

파이썬에서 C++ 객체에 어떻게 인터페이스 합니까?

Setup 파일을 사용하여 모듈을 추가했는데 make가 실패합니다; 왜 그렇습니까?

확장을 어떻게 디버깅합니까?

리눅스 시스템에서 파이썬 모듈을 컴파일하고 싶지만, 일부 파일이 없습니다. 왜 그렇습니까?

“잘못된 입력”과 “불완전한 입력”을 어떻게 구별할 수 있습니까?

정의되지 않은 g++ 기호 __builtin_new나 __pure_virtual을 어떻게 찾을 수 있습니까?

일부 메서드는 C로 구현되고 그 밖의 것은 파이썬으로 구현된 (예를 들어 상속을 통해) 객체 클래스를 만들 수 있습니까?

C로 나만의 함수를 만들 수 있습니까?

그렇습니다. 함수, 변수, 예외 및 심지어 새로운 형을 포함하는 내장 모듈을 C로 만들 수 있습니다. 파이썬 인터프리터 확장 및 내장 문서에 설명되어 있습니다.

대부분의 중급이나 고급 파이썬 서적에서도 이 주제를 다룰 것입니다.

C++로 나만의 함수를 만들 수 있습니까?

그렇습니다, C++에 있는 C 호환성 기능을 사용합니다. 파이썬 인클루드(include) 파일 주위에 extern "C" { ... }를 배치하고 파이썬 인터프리터가 호출할 각 함수 앞에 extern "C"를 배치하십시오. 생성자를 가진 전역이나 정적(static) C++ 객체는 대개 좋은 생각이 아닙니다.

C를 쓰는 것은 어렵습니다; 대안이 있습니까?

수행하려는 작업에 따라, 여러분 만의 C 확장을 작성하는 여러 가지 대안이 있습니다.

Cython [https://cython.org] and its relative Pyrex [https://www.csse.canterbury.ac.nz/greg.ewing/python/Pyrex/] are compilers that accept a slightly modified form of Python and generate the corresponding C code. Cython and Pyrex make it possible to write an extension without having to learn Python’s C API.

If you need to interface to some C or C++ library for which no Python extension currently exists, you can try wrapping the library’s data types and functions with a tool such as SWIG [https://www.swig.org]. SIP [https://github.com/Python-SIP/sip], CXX [https://cxx.sourceforge.net/] Boost [https://www.boost.org/libs/python/doc/index.html], or Weave [https://github.com/scipy/weave] are also alternatives for wrapping C++ libraries.

C에서 임의의 파이썬 문장을 어떻게 실행할 수 있습니까?

이를 수행하는 최상위 수준 함수는 PyRun_SimpleString()이며, 이는 모듈 __main__의 컨텍스트에서 실행될 단일 문자열 인자를 취하고 성공하면 0을 반환하고 (SyntaxError를 포함하는) 예외가 발생하면 -1을 반환합니다. 더 많은 제어를 원하면, PyRun_String()을 사용하십시오; Python/pythonrun.c에 있는 PyRun_SimpleString() 소스를 참조하십시오.

C에서 임의의 파이썬 표현식을 어떻게 평가할 수 있습니까?

이전 질문에서 나온 PyRun_String() 함수를 start 기호 Py_eval_input을 사용하여 호출하십시오; 표현식을 구문 분석하고, 평가하고 값을 반환합니다.

파이썬 객체에서 C값을 어떻게 추출합니까?

That depends on the object’s type. If it’s a tuple, PyTuple_Size() returns its length and PyTuple_GetItem() returns the item at a specified index. Lists have similar functions, PyList_Size() and PyList_GetItem().

For bytes, PyBytes_Size() returns its length and PyBytes_AsStringAndSize() provides a pointer to its value and its length. Note that Python bytes objects may contain null bytes so C’s strlen() should not be used.

객체의 형을 검사하려면, 먼저 NULL이 아닌지 확인한 다음 PyBytes_Check(), PyTuple_Check(), PyList_Check() 등을 사용하십시오.

소위 ‘추상’ 인터페이스가 제공하는 파이썬 객체에 대한 고수준 API도 있습니다 – 자세한 내용은 Include/abstract.h를 읽으십시오. PySequence_Length(), PySequence_GetItem() 등과 같은 호출로 모든 종류의 파이썬 시퀀스와 인터페이스 할 수 있을 뿐만 아니라 숫자(PyNumber_Index() 등)와 PyMapping API의 매핑과 같은 다른 많은 유용한 프로토콜을 지원합니다.

Py_BuildValue()를 사용하여 임의 길이의 튜플을 만드는 방법은 무엇입니까?

그럴 수 없습니다. 대신 PyTuple_Pack()을 사용하십시오.

C에서 객체의 메서드를 어떻게 호출합니까?

PyObject_CallMethod() 함수는 객체의 임의의 메서드를 호출하는 데 사용할 수 있습니다. 매개 변수는 객체, 호출할 메서드의 이름, Py_BuildValue()에 사용되는 것과 같은 포맷 문자열 및 인자 값입니다:

PyObject *
PyObject_CallMethod(PyObject *object, const char *method_name,
                    const char *arg_format, ...);

메서드가 있는 모든 객체에서 작동합니다 – 내장이나 사용자 정의 모두 작동합니다. 반환 값을 Py_DECREF()할 책임은 여러분에게 있습니다.

예를 들어, 인자 10, 0으로 파일 객체의 “seek” 메서드를 호출하려면 (파일 객체 포인터가 “f”라고 가정합니다):

res = PyObject_CallMethod(f, "seek", "(ii)", 10, 0);
if (res == NULL) {
        ... an exception occurred ...
}
else {
        Py_DECREF(res);
}

PyObject_CallObject()는 항상 인자 목록에 대한 튜플을 원하므로, 인자 없이 함수를 호출하려면, format으로 “()”를 전달하고, 하나의 인자로 함수를 호출하려면, 인자를 괄호로 묶습니다, 예를 들어 “(i)”.

PyErr_Print()의 출력(또는 stdout/stderr로 인쇄되는 모든 것)을 어떻게 잡습니까?

파이썬 코드에서, write() 메서드를 지원하는 객체를 정의하십시오. 이 객체를 sys.stdout과 sys.stderr에 대입하십시오. print_error를 호출하거나 표준 트레이스백 메커니즘이 작동하도록 두십시오. 그러면 출력은 여러분의 write() 메서드가 보내는 곳으로 갑니다.

이렇게 하는 가장 쉬운 방법은 io.StringIO 클래스를 사용하는 것입니다:

>>> import io, sys
>>> sys.stdout = io.StringIO()
>>> print('foo')
>>> print('hello world!')
>>> sys.stderr.write(sys.stdout.getvalue())
foo
hello world!

같은 작업을 수행하는 사용자 정의 객체는 다음과 같습니다:

>>> import io, sys
>>> class StdoutCatcher(io.TextIOBase):
...     def __init__(self):
...         self.data = []
...     def write(self, stuff):
...         self.data.append(stuff)
...
>>> import sys
>>> sys.stdout = StdoutCatcher()
>>> print('foo')
>>> print('hello world!')
>>> sys.stderr.write(''.join(sys.stdout.data))
foo
hello world!

C에서 파이썬으로 작성된 모듈에 어떻게 액세스합니까?

다음과 같이 모듈 객체에 대한 포인터를 얻을 수 있습니다:

module = PyImport_ImportModule("<modulename>");

모듈을 아직 임포트 하지 않았으면 (즉, sys.modules에 아직 없으면), 이것은 모듈을 초기화합니다; 그렇지 않으면 단순히 sys.modules["<modulename>"]의 값을 반환합니다. 이것은 모듈을 어떤 이름 공간에도 넣지 않음에 유의하십시오 – 단지 초기화되도록 하고 sys.modules에 저장되도록 합니다.

그런 다음, 다음과 같이 모듈의 어트리뷰트(즉 모듈에 정의된 모든 이름)에 액세스할 수 있습니다:

attr = PyObject_GetAttrString(module, "<attrname>");

모듈에 있는 변수에 대입하기 위해 PyObject_SetAttrString()을 호출하는 것도 작동합니다.

파이썬에서 C++ 객체에 어떻게 인터페이스 합니까?

요구 사항에 따라 여러 가지 접근 방식이 있습니다. 이 작업을 수동으로 수행하려면, “확장 및 내장” 문서를 읽는 것으로 시작하십시오. 파이썬 런타임 시스템의 경우 C와 C++ 사이에는 큰 차이가 없다는 것을 상기하십시오 – 따라서 C 구조체 (포인터) 형을 중심으로 새로운 파이썬 형을 작성하는 전략이 C++ 객체에도 적용됩니다.

C++ 라이브러리의 경우, C를 쓰는 것은 어렵습니다; 대안이 있습니까?를 참조하십시오.

Setup 파일을 사용하여 모듈을 추가했는데 make가 실패합니다; 왜 그렇습니까?

Setup은 개행으로 끝나야 하며, 개행이 없으면 빌드 프로세스가 실패합니다. (이 문제를 해결하려면 지저분한 셸 스크립트 해킹이 필요하며, 이 버그는 너무 사소해서 그런 노력을 들일만 한 가치가 없는 것 같습니다.)

확장을 어떻게 디버깅합니까?

동적으로 로드된 확장에 GDB를 사용할 때, 확장이 로드될 때까지 확장에 중단점을 설정할 수 없습니다.

.gdbinit 파일에서 (또는 대화식으로) 다음 명령을 추가하십시오:

br _PyImport_LoadDynamicModule

그런 다음, GDB를 실행할 때:

$ gdb /local/bin/python
gdb) run myscript.py
gdb) continue # repeat until your extension is loaded
gdb) finish   # so that your extension is loaded
gdb) br myfunction.c:50
gdb) continue

리눅스 시스템에서 파이썬 모듈을 컴파일하고 싶지만, 일부 파일이 없습니다. 왜 그렇습니까?

Most packaged versions of Python omit some files required for compiling Python extensions.

For Red Hat, install the python3-devel RPM to get the necessary files.

For Debian, run apt-get install python3-dev.

“잘못된 입력”과 “불완전한 입력”을 어떻게 구별할 수 있습니까?

때로 파이썬 대화식 인터프리터의 동작을 흉내 내고 싶을 때가 있습니다. 이것은 입력이 불완전할 때 (예를 들어, “if” 문의 시작을 입력했거나 괄호나 삼중 문자열 따옴표를 닫지 않았을 때) 계속 프롬프트를 표시하지만, 입력이 유효하지 않으면 즉시 문법 에러 메시지를 표시합니다.

파이썬에서는 codeop 모듈을 사용할 수 있습니다. 이 모듈은 구문 분석기의 동작을 충분히 근사합니다. 예를 들어, IDLE은 이것을 사용합니다.

C에서 이렇게 하는 가장 쉬운 방법은 PyRun_InteractiveLoop()를 호출하고 (아마 별도의 스레드에서), 파이썬 인터프리터가 입력을 처리하도록 하는 것입니다. PyOS_ReadlineFunctionPointer() 가 여러분의 사용자 정의 입력 함수를 가리 키도록 설정할 수도 있습니다. 자세한 힌트는 Modules/readline.c와 Parser/myreadline.c를 참조하십시오.

정의되지 않은 g++ 기호 __builtin_new나 __pure_virtual을 어떻게 찾을 수 있습니까?

g++ 확장 모듈을 동적으로 로드하려면, 파이썬을 다시 컴파일하고, g++를 사용하여 다시 링크하고 (파이썬 Modules Makefile에서 LINKCC를 변경하십시오), g++를 사용하여 여러분의 확장 모듈을 링크해야 합니다 (예를 들어, g++ -shared -o mymodule.so mymodule.o).

일부 메서드는 C로 구현되고 그 밖의 것은 파이썬으로 구현된 (예를 들어 상속을 통해) 객체 클래스를 만들 수 있습니까?

그렇습니다, int, list, dict 등과 같은 내장 클래스를 상속할 수 있습니다.

The Boost Python Library (BPL, https://www.boost.org/libs/python/doc/index.html) provides a way of doing this from C++ (i.e. you can inherit from an extension class written in C++ using the BPL).

윈도우 파이썬 FAQ

목차

윈도우 파이썬 FAQ

윈도우에서 파이썬 프로그램을 실행하려면 어떻게 해야 합니까?

파이썬 스크립트 실행 파일로 만들려면 어떻게 해야 합니까?

왜 때때로 파이썬은 시작하는 데 시간이 오래 걸립니까?

파이썬 스크립트에서 실행 파일을 만드는 방법은 무엇입니까?

*.pyd 파일은 DLL과 동일합니까?

윈도우 응용프로그램에 파이썬을 포함하려면 어떻게 해야 합니까?

편집기가 내 파이썬 소스에 탭을 삽입하지 않도록 하려면 어떻게 해야 합니까?

블로킹 없이 키 입력을 확인하려면 어떻게 해야 합니까?

How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?

윈도우에서 파이썬 프로그램을 실행하려면 어떻게 해야 합니까?

이 질문은 명확한 질문이 아닙니다. 이미 윈도우 명령 줄에서 프로그램을 실행하는 것에 익숙 하다면 이 모든 것이 분명할 것입니다. 그렇지 않으면, 좀 더 지침이 필요할 수 있습니다.

Unless you use some sort of integrated development environment, you will end up typing Windows commands into what is referred to as a “Command prompt window”. Usually you can create such a window from your search bar by searching for cmd. You should be able to recognize when you have started such a window because you will see a Windows “command prompt”, which usually looks like this:

C:\>

아마 글자가 다르고, 그 뒤에 다른 것들이 있을 수 있습니다. 그러므로 다음과 같은 것을 쉽게 볼 수 있습니다:

D:\YourName\Projects\Python>

컴퓨터 설정 방법과 최근에 끝낸 그 밖의 것에 의존적입니다. 일단 이런 창을 시작했다면, 파이썬 프로그램을 실행할 준비가 된 것입니다.

파이썬 스크립트는 파이썬 인터프리터 라는 다른 프로그램에서 진행할 필요가 있다는 것을 알고 있어야 합니다. 인터프리터는 스크립트를 읽고, 바이트 코드로 컴파일하고, 바이트 코드를 실행하여 프로그램을 구동합니다. 그렇다면, 인터프리터를 통해 파이썬을 처리하려면 어떻게 준비해야 하겠습니까?

먼저, 명령 창이 “py”라는 단어를 해석기를 시작하는 지시로 인식하는지 확인해야합니다. 명령 창을 열고 있으면, 명령 py 를 입력하고 return 키를 눌러야 합니다:

C:\Users\YourName> py

다음과 같이 표시됩니다:

Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

인터프리터를 “대화형 모드”로 시작했습니다. 즉, 파이썬 문장이나 표현식을 대화식으로 입력하여 대기하는 중에 실행 혹은 평가시킬 수 있습니다. 이것은 파이썬의 가장 강력한 기능 중 하나입니다. 선택한 몇 가지 수식을 입력하여 확인하고 그 결과를 확인하십시오:

>>> print("Hello")
Hello
>>> "Hello" * 3
'HelloHelloHello'

많은 사람이 대화형 모드를 편리하면서도 프로그래밍이 가능한 계산기로 사용합니다. 대화형 파이썬 세션을 종료하려면, exit() 함수를 호출하거나 Z 를 입력하면서 Ctrl 키를 누르고 나서 “Enter” 키를 눌러 윈도우 명령 프롬프트로 돌아갑니다.

또한, 시작 ‣ 프로그램 ‣ Python 3.x ‣ Python(명령 줄) 메뉴 선택과 같은 시작 메뉴 항목을 찾아볼 수 있으며, 그 결과 새 창에서 >>> 프롬프트를 볼 수 있습니다. 이 경우, exit() 함수를 호출하거나 Ctrl-Z 를 입력하면 창이 사라집니다. 윈도우에서 단일 “python” 명령을 실행하는 중이고, 인터프리터를 종료하면 창을 닫습니다.

이제 py 명령이 인식되었으므로, 당신은 당신의 파이썬 스크립트를 줄 수 있습니다. 파이썬 스크립트에 절대 경로나 상대 경로를 지정해야 할 것입니다. 당신의 파이썬 스크립트가 hello.py 라는 이름으로 당신의 데스크톱에 위치한다고 하면, 명령 프롬프트가 홈 디렉토리에 잘 열려있으므로 다음과 같이 내용이 표시됩니다:

C:\Users\YourName>

그래서 이제 스크립트 경로 뒤에 py 를 입력하여 파이썬 스크립트를 제공하기 위해 py 명령을 요청할 것입니다:

C:\Users\YourName> py Desktop\hello.py
hello

파이썬 스크립트 실행 파일로 만들려면 어떻게 해야 합니까?

윈도우에서 표준 파이썬 설치관리자는 이미 .py 확장자와 파일 유형(Python.File)을 연결했고, 인터프리터(D:\Program Files\Python\python.exe "%1" %*)를 실행하는 open 명령의 파일 유형을 제공합니다. 이것은 명령 프롬프트에서 ‘foo.py’ 과 같은 스크립트 실행파일을 만들기에 충분합니다. 확장자명 없이 ‘foo’ 를 입력하여 스크립트를 실행하려면 PATHEXT 환경 변수에 .py를 추가해야 합니다.

왜 때때로 파이썬은 시작하는 데 시간이 오래 걸립니까?

일반적으로 파이썬은 윈도우에서 매우 빠르게 시작되지만, 때때로 파이썬을 시작하는 데 갑자기 오랜 시간이 걸린다는 버그 보고서가 있습니다. 이러한 것은 파이썬이 동일하게 구성된 것으로 보이는 다른 윈도우 시스템에서 잘 작동하기 때문에 더욱 더 곤혹스럽게 만듭니다.

이 문제는 해당 컴퓨터의 바이러스 검사 소프트웨어의 잘못된 설정으로 발생하는 것일 수 있습니다. 일부 바이러스 스캐너는 파일 시스템으로부터 읽은 모든 것을 모니터링하도록 스캐너를 구성할 때 두 자릿수 규모의 시동 오버헤드를 도입하는 것으로 알려져 있습니다. 시스템에서 바이러스 검사 소프트웨어의 구성을 확인하여 실제로 동일하게 구성되었는지 확인하십시오. 모든 파일 시스템 읽기 작업을 검색하도록 구성된 경우, McAfee는 특히 문제를 일으킵니다.

파이썬 스크립트에서 실행 파일을 만드는 방법은 무엇입니까?

See 파이썬 스크립트로 독립 실행형 바이너리를 만들려면 어떻게 해야 합니까? for a list of tools that can be used to make executables.

*.pyd 파일은 DLL과 동일합니까?

예, .pyd 파일은 dll 이지만, 몇 가지 차이점이 있습니다. 만약 당신이 foo.pyd 라는 이름의 DLL을 가지고 있다면, PyInit_foo() 함수를 반드시 가지고 있어야 합니다. 당신은 파이썬 “import foo”를 쓸 수 있으며, 파이썬은 (foo.py, foo.pyc 뿐만 아니라) foo.pyd 를 검색할 것이고, 이를 발견하면 초기화하기 위해 PyInit_foo() 호출을 시도할 것입니다. 윈도우에서 DLL 의 존재를 요구할 것이기 때문에 .exe를 foo.lib와 링크하면 안 됩니다.

foo.pyd에 대한 검색 경로는 윈도우에서 foo.dll을 검색하는 데 사용하는 경로가 아닌 PYTHONPATH임을 유의하십시오. 또한, 프로그램을 실행하기 위해 foo.pyd가 있을 필요는 없지만, 프로그램을 dll과 링크한 경우에는 dll이 필요합니다. 물론, import foo 를 하기 위해서는 foo.pyd가 필요합니다. DLL에서 링키지는 소스 코드에서 __declspec(dllexport) 로 선언됩니다. .pyd에서 링키지는 사용 가능한 함수 목록에 정의됩니다.

윈도우 응용프로그램에 파이썬을 포함하려면 어떻게 해야 합니까?

윈도우 앱에서 파이썬 인터프리터를 포함하려면 다음과 같이 요약할 수 있습니다:

Do not build Python into your .exe file directly. On Windows, Python must be a DLL to handle importing modules that are themselves DLL’s. (This is the first key undocumented fact.) Instead, link to pythonNN.dll; it is typically installed in C:\Windows\System. NN is the Python version, a number such as “33” for Python 3.3.

두 가지 방법으로 파이썬에 링크할 수 있습니다. 로드 타임 링크는 pythonNN.lib 에 대한 링크를 의미하고, 런타임 링크는 pythonNN.dll 에 대한 링크를 의미합니다. (일반 참고: pythonNN.lib 는 pythonNN.dll 에 해당하는 소위 “import lib”입니다. 오직 링커를 위해 기호만 정의합니다)

런타임 링크는 링크 옵션을 크게 단순화합니다. 모든 것은 런타임 중에 발생합니다. 당신의 코드는 윈도우 LoadLibraryEx() 루틴을 사용하여 pythonNN.dll 을 로드해야 합니다. 그 코드는 윈도우 GetProcAddress() 루틴에서 얻은 포인터를 사용하여 pythonNN.dll (파이썬의 C API)의 엑세스 루틴 및 데이터를 사용해야 합니다. 매크로는 이러한 포인터를 파이썬 C API에서 루틴을 호출하는 모든 C 코드에 투명하게 사용할 수 있습니다.

If you use SWIG, it is easy to create a Python “extension module” that will make the app’s data and methods available to Python. SWIG will handle just about all the grungy details for you. The result is C code that you link into your .exe file (!) You do not have to create a DLL file, and this also simplifies linking.

SWIG는 확장 모듈의 이름에 따라 이름이 달라지는 초기화 함수(C 함수)를 생성합니다. 예를 들어, 모듈의 이름이 leo인 경우, 초기화 함수를 initleo()로 합니다. SWIG 섀도 클래스를 사용하면 initleoc()로 합니다. 이것은 섀도 클래스가 사용하는 대부분 숨겨진 조력자 클래스를 초기화합니다.

2단계에서 C 코드를 .exe 파일에 링크할 수 있는 이유는 초기화 함수를 호출하는 것이 모듈을 파이썬으로 임포트하는 것과 동일하기 때문입니다! (이것이 문서화되지 않은 두 번째 사실입니다)

간단히 말해서, 당신은 당신의 확장 모듈로 파이썬 인터프리터를 초기화하기 위해 다음 코드를 사용할 수 있습니다.

#include <Python.h>
...
Py_Initialize();  // Initialize Python.
initmyAppc();  // Initialize (import) the helper class.
PyRun_SimpleString("import myApp");  // Import the shadow class.

파이썬의 C API에는 두 가지 문제가 있는데, 이것은 당신이 PythonNN.dll을 만드는 데 사용되는 컴파일러인 MSVC 이외의 컴파일러를 사용하면 명백해집니다.

Problem 1: The so-called “Very High Level” functions that take FILE * arguments will not work in a multi-compiler environment because each compiler’s notion of a struct FILE will be different. From an implementation standpoint these are very low level functions.

문제 2: 반환값이 void인 C 함수의 래퍼를 생성할 때 SWIG는 다음과 같은 코드를 생성합니다:

Py_INCREF(Py_None);
_resultobj = Py_None;
return _resultobj;

아아, Py_None은 pythonNN.dll 내부의 _Py_NoneStruct라는 복잡한 데이터 구조에 대한 참조로 확장하는 매크로입니다. 다시 말하자면, 이 코드는 멀티 컴파일러 환경에서 실패할 것입니다. 다음과 같은 코드로 바꾸십시오:

return Py_BuildValue("");

저는 이것을 작동시키지는 못했지만, SWIG의 %typemap 명령을 사용하여 자동으로 변경하는 것이 가능할지도 모릅니다(저는 완전 SWIG 초보자입니다).

윈도우 앱 내부에서 파이썬 셸 스크립트를 사용하여 파이썬 인터프리터 창을 설치하는 것은 좋은 생각이 아닙니다. 결과 창은 앱의 창 시스템과는 독립적일 것입니다. 오히려, 당신(또는 wxPythonWindow 클래스)은 “native” 인터프리터 창을 만들어야 합니다. 이 창은 파이썬 인터프리터와 연결하기 쉽습니다. 당신은 파이썬의 i/o를 읽기 및 쓰기를 지원하는 모든 객체로 리디렉션할 수 있으므로 read() 와 write() 메서드를 포함하는 파이썬 객체(확장 모듈에 정의됨)만 있으면 됩니다.

편집기가 내 파이썬 소스에 탭을 삽입하지 않도록 하려면 어떻게 해야 합니까?

FAQ는 탭을 사용하는 것을 권장하지 않으며, 파이썬 스타일 안내서( PEP 8 [https://peps.python.org/pep-0008/] )는 분산된 파이썬 코드에 대해 4 개의 스페이스를 권장합니다. 이 또한 Emacs python-mode의 기본값입니다.

모든 편집기에서 탭과 스페이스를 혼용하는 것은 좋은 생각이 아닙니다. 이 점에서 MSVC는 다르지 않으며 스페이스를 사용하기 쉽게 구성됩니다: 다음 행동을 따라 해보십시오 Tools ‣ Options ‣ Tabs, 그리고 파일 유형은 “”Default”로 하고 “Tab size”와 “Indent size”는 4로 설정하고, “Insert spaces”를 라디오 버튼으로 선택합니다.

만일 혼용된 탭과 스페이스로 인해 선행 공백에 문제가 발생하는 경우, 파이썬이 IndentationError 나 TabError 를 발생시킵니다. 또한, tabnanny 모듈을 실행하여 배치 모드에서 디렉터리 트리를 확인할 수도 있습니다.

블로킹 없이 키 입력을 확인하려면 어떻게 해야 합니까?

msvcrt 모듈을 사용합니다. 이것은 표준 윈도우-특정 확장 모듈입니다. 이것은 키보드 히트가 존재하는지를 확인하는 kbhit() 와 에코 없이 문자를 얻는 getch() 를 정의합니다.

How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?

This can occur on Python 3.5 and later when using Windows 8.1 or earlier without all updates having been installed. First ensure your operating system is supported and is up to date, and if that does not resolve the issue, visit the Microsoft support page [https://support.microsoft.com/en-us/help/3118401/] for guidance on manually installing the C Runtime update.

그래픽 사용자 인터페이스 FAQ

목차

그래픽 사용자 인터페이스 FAQ

일반적인 GUI 질문

What GUI toolkits exist for Python?

Tkinter 질문

Tkinter 응용 프로그램을 어떻게 고정(freeze)합니까?

I/O를 기다리는 동안 Tk 이벤트를 처리하도록 할 수 있습니까?

Tkinter에서 키 바인딩이 동작하지 않습니다: 이유가 무엇입니까?

일반적인 GUI 질문

What GUI toolkits exist for Python?

Standard builds of Python include an object-oriented interface to the Tcl/Tk widget set, called tkinter. This is probably the easiest to install (since it comes included with most binary distributions [https://www.python.org/downloads/] of Python) and use. For more info about Tk, including pointers to the source, see the Tcl/Tk home page [https://www.tcl.tk]. Tcl/Tk is fully portable to the macOS, Windows, and Unix platforms.

Depending on what platform(s) you are aiming at, there are also several alternatives. A list of cross-platform [https://wiki.python.org/moin/GuiProgramming#Cross-Platform_Frameworks] and platform-specific [https://wiki.python.org/moin/GuiProgramming#Platform-specific_Frameworks] GUI frameworks can be found on the python wiki.

Tkinter 질문

Tkinter 응용 프로그램을 어떻게 고정(freeze)합니까?

Freeze는 독립 실행형 응용 프로그램을 만드는 도구입니다. Tkinter 응용 프로그램을 고정할 때, 응용 프로그램은 여전히 Tcl과 Tk 라이브러리가 필요하므로 진정한 독립 실행형이 아닙니다.

One solution is to ship the application with the Tcl and Tk libraries, and point to them at run-time using the TCL_LIBRARY and TK_LIBRARY environment variables.

Various third-party freeze libraries such as py2exe and cx_Freeze have handling for Tkinter applications built-in.

I/O를 기다리는 동안 Tk 이벤트를 처리하도록 할 수 있습니까?

On platforms other than Windows, yes, and you don’t even need threads! But you’ll have to restructure your I/O code a bit. Tk has the equivalent of Xt’s XtAddInput() call, which allows you to register a callback function which will be called from the Tk mainloop when I/O is possible on a file descriptor. See 파일 처리기.

Tkinter에서 키 바인딩이 동작하지 않습니다: 이유가 무엇입니까?

An often-heard complaint is that event handlers bound to events with the bind() method don’t get handled even when the appropriate key is pressed.

가장 흔한 원인은 바인딩이 적용되는 위젯에 “키보드 포커스”가 없는 것입니다. focus 명령에 대한 Tk 설명서를 확인하십시오. 보통 위젯은 그것을 클릭할 때 키보드 포커스를 받습니다 (레이블은 그렇지 않습니다; takefocus 옵션을 보십시오).

“왜 내 컴퓨터에 파이썬이 설치되어 있습니까?” FAQ

파이썬이 무엇입니까?

파이썬은 프로그래밍 언어입니다. 많은 다른 응용 프로그램에 사용됩니다. 파이썬은 배우기 쉬우므로 일부 고등학교와 대학에서는 입문 프로그래밍 언어로 사용되지만, Google, NASA 및 Lucasfilm Ltd.와 같은 곳에서 전문 소프트웨어 개발자가 사용하기도 합니다.

파이썬에 대해 더 알고 싶다면, 파이썬 입문자 지침서 [https://wiki.python.org/moin/BeginnersGuide]부터 시작하십시오.

내 컴퓨터에 파이썬이 설치된 이유는 무엇입니까?

파이썬이 시스템에 설치되어 있지만 설치한 기억이 없다면, 그렇게 될 수 있는 몇 가지 가능한 방법이 있습니다.

아마도 컴퓨터의 다른 사용자가 프로그래밍을 배우고 싶어 하고 그것을 설치했을 것입니다; 당신은 누가 컴퓨터를 사용했고 설치했는지 추측해야 합니다.

컴퓨터에 설치된 제삼자 응용 프로그램이 파이썬으로 작성되었으며, 파이썬 설치를 포함할 수 있습니다. GUI 프로그램에서 네트워크 서버와 관리 스크립트에 이르기까지 그런 응용 프로그램이 많이 있습니다.

일부 윈도우 컴퓨터에는 파이썬이 설치되어 있습니다. 이 글을 쓰는 시점에, 우리는 파이썬이 포함된 Hewlett-Packard와 Compaq의 컴퓨터에 대해 알고 있습니다. 분명히 HP/Compaq의 관리 도구 중 일부가 파이썬으로 작성되었을 겁니다.

Many Unix-compatible operating systems, such as macOS and some Linux distributions, have Python installed by default; it’s included in the base installation.

파이썬을 삭제할 수 있습니까?

파이썬이 어디서 왔는지에 달려 있습니다.

누군가 의도적으로 설치했으면, 아무 문제도 일으키지 않고 제거할 수 있습니다. 윈도우에서는, 제어판의 프로그램 추가/제거 아이콘을 사용하십시오.

제삼자 응용 프로그램에서 파이썬을 설치했다면, 제거할 수도 있지만, 해당 응용 프로그램이 더는 작동하지 않게 됩니다. 파이썬을 직접 제거하는 대신 해당 응용 프로그램의 제거 프로그램을 사용해야 합니다.

파이썬이 운영체제와 함께 제공되었다면, 제거하는 것은 바람직하지 않습니다. 제거하면, 파이썬으로 작성된 모든 도구가 더는 실행되지 않으며, 그중 일부는 중요할 수 있습니다. 문제를 해결하려면 다시 시스템을 재설치해야 할 수 있습니다.

Deprecations

Pending removal in Python 3.15

The import system:

Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

Setting __package__ on a module while failing to set __spec__.parent is deprecated. In Python 3.15, __package__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

ctypes:

The undocumented ctypes.SetPointerType() function has been deprecated since Python 3.13.

http.server:

The obsolete and rarely used CGIHTTPRequestHandler has been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.

The --cgi flag to the python -m http.server command-line interface has been deprecated since Python 3.13.

locale:

The getdefaultlocale() function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817 [https://github.com/python/cpython/issues/90817]), but has been postponed to Python 3.15. Use getlocale(), setlocale(), and getencoding() instead. (Contributed by Hugo van Kemenade in gh-111187 [https://github.com/python/cpython/issues/111187].)

pathlib:

PurePath.is_reserved() has been deprecated since Python 3.13. Use os.path.isreserved() to detect reserved paths on Windows.

platform:

java_ver() has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.

threading:

RLock() will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.

types:

types.CodeType: Accessing co_lnotab was deprecated in PEP 626 [https://peps.python.org/pep-0626/] since 3.10 and was planned to be removed in 3.12, but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

typing:

The undocumented keyword argument syntax for creating NamedTuple classes (for example, Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.

The typing.no_type_check_decorator() decorator function has been deprecated since Python 3.13. After eight years in the typing module, it has yet to be supported by any major type checker.

wave:

The getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes have been deprecated since Python 3.13.

Pending removal in Python 3.16

The import system:

Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

array:

The 'u' format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the 'w' format code (Py_UCS4) for Unicode characters instead.

asyncio:

asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins:

Bitwise inversion on boolean types, ~True or ~False has been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2 and -1). Use not x instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to int explicitly (~int(x)).

shutil:

The ExecError exception has been deprecated since Python 3.14. It has not been used by any function in shutil since Python 3.4, and is now an alias of RuntimeError.

symtable:

The Class.get_methods method has been deprecated since Python 3.14.

sys:

The _enablelegacywindowsfsencoding() function has been deprecated since Python 3.13. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead.

tarfile:

The undocumented and unused TarFile.tarfile attribute has been deprecated since Python 3.13.

Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

argparse:

Nesting argument groups and nesting mutually exclusive groups are deprecated.

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated.

The argparse.FileType type converter is deprecated.

array’s 'u' format code (gh-57281 [https://github.com/python/cpython/issues/57281])

builtins:

bool(NotImplemented).

Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In a future release it will be changed to a syntax error. (gh-87999 [https://github.com/python/cpython/issues/87999])

Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of int.

Support for __float__() method returning a strict subclass of float: these methods will be required to return an instance of float.

Support for __complex__() method returning a strict subclass of complex: these methods will be required to return an instance of complex.

Delegation of int() to __trunc__() method.

Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

codeobject.co_lnotab: use the codeobject.co_lines() method instead.

datetime:

utcnow(): use datetime.datetime.now(tz=datetime.UTC).

utcfromtimestamp(): use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).

gettext: Plural value must be an integer.

importlib:

load_module() method: use exec_module() instead.

cache_from_source() debug_override parameter is deprecated: use the optimization parameter instead.

importlib.metadata:

EntryPoints tuple interface.

Implicit None on return values.

logging: the warn() method has been deprecated since Python 3.3, use warning() instead.

mailbox: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

os: Calling os.register_at_fork() in multi-threaded process.

pydoc.ErrorDuringImport: A tuple value for exc_info parameter is deprecated, use an exception instance.

re: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

sre_compile, sre_constants and sre_parse modules.

shutil: rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

ssl options and protocols:

ssl.SSLContext without protocol argument is deprecated.

ssl.SSLContext: set_npn_protocols() and selected_npn_protocol() are deprecated: use ALPN instead.

ssl.OP_NO_SSL* options

ssl.OP_NO_TLS* options

ssl.PROTOCOL_SSLv3

ssl.PROTOCOL_TLS

ssl.PROTOCOL_TLSv1

ssl.PROTOCOL_TLSv1_1

ssl.PROTOCOL_TLSv1_2

ssl.TLSVersion.SSLv3

ssl.TLSVersion.TLSv1

ssl.TLSVersion.TLSv1_1

sysconfig.is_python_build() check_home parameter is deprecated and ignored.

threading methods:

threading.Condition.notifyAll(): use notify_all().

threading.Event.isSet(): use is_set().

threading.Thread.isDaemon(), threading.Thread.setDaemon(): use threading.Thread.daemon attribute.

threading.Thread.getName(), threading.Thread.setName(): use threading.Thread.name attribute.

threading.currentThread(): use threading.current_thread().

threading.activeCount(): use threading.active_count().

typing.Text (gh-92332 [https://github.com/python/cpython/issues/92332]).

unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.

urllib.parse deprecated functions: urlparse() instead

splitattr()

splithost()

splitnport()

splitpasswd()

splitport()

splitquery()

splittag()

splittype()

splituser()

splitvalue()

to_bytes()

wsgiref: SimpleHandler.stdout.write() should not do partial writes.

xml.etree.ElementTree: Testing the truth value of an Element is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.

zipimport.zipimporter.load_module() is deprecated: use exec_module() instead.

C API deprecations

Pending removal in Python 3.15

The bundled copy of libmpdecimal.

The PyImport_ImportModuleNoBlock(): Use PyImport_ImportModule() instead.

PyWeakref_GetObject() and PyWeakref_GET_OBJECT(): Use PyWeakref_GetRef() instead.

Py_UNICODE type and the Py_UNICODE_WIDE macro: Use wchar_t instead.

Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.base_exec_prefix and sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.base_prefix and sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

Py_TPFLAGS_HAVE_FINALIZE: Unneeded since Python 3.8.

PyErr_Fetch(): Use PyErr_GetRaisedException() instead.

PyErr_NormalizeException(): Use PyErr_GetRaisedException() instead.

PyErr_Restore(): Use PyErr_SetRaisedException() instead.

PyModule_GetFilename(): Use PyModule_GetFilenameObject() instead.

PyOS_AfterFork(): Use PyOS_AfterFork_Child() instead.

PySlice_GetIndicesEx(): Use PySlice_Unpack() and PySlice_AdjustIndices() instead.

PyUnicode_AsDecodedObject(): Use PyCodec_Decode() instead.

PyUnicode_AsDecodedUnicode(): Use PyCodec_Decode() instead.

PyUnicode_AsEncodedObject(): Use PyCodec_Encode() instead.

PyUnicode_AsEncodedUnicode(): Use PyCodec_Encode() instead.

PyUnicode_READY(): Unneeded since Python 3.12

PyErr_Display(): Use PyErr_DisplayException() instead.

_PyErr_ChainExceptions(): Use _PyErr_ChainExceptions1() instead.

PyBytesObject.ob_shash member: call PyObject_Hash() instead.

PyDictObject.ma_version_tag member.

Thread Local Storage (TLS) API:

PyThread_create_key(): Use PyThread_tss_alloc() instead.

PyThread_delete_key(): Use PyThread_tss_free() instead.

PyThread_set_key_value(): Use PyThread_tss_set() instead.

PyThread_get_key_value(): Use PyThread_tss_get() instead.

PyThread_delete_key_value(): Use PyThread_tss_delete() instead.

PyThread_ReInitTLS(): Unneeded since Python 3.7.

용어집

>>>

The default Python prompt of the interactive shell. Often seen for code examples which can be executed interactively in the interpreter.

...

다음과 같은 것들을 가리킬 수 있습니다:

The default Python prompt of the interactive shell when entering the code for an indented code block, when within a pair of matching left and right delimiters (parentheses, square brackets, curly braces or triple quotes), or after specifying a decorator.

Ellipsis 내장 상수.

abstract base class (추상 베이스 클래스)

추상 베이스 클래스는 hasattr() 같은 다른 테크닉들이 불편하거나 미묘하게 잘못된 (예를 들어, 매직 메서드) 경우, 인터페이스를 정의하는 방법을 제공함으로써 덕 타이핑 을 보완합니다. ABC는 가상 서브 클래스를 도입하는데, 클래스를 계승하지 않으면서도 isinstance() 와 issubclass() 에 의해 감지될 수 있는 클래스들입니다; abc 모듈 설명서를 보세요. 파이썬에는 많은 내장 ABC 들이 따라오는데 다음과 같은 것들이 있습니다: 자료 구조 (collections.abc 모듈에서), 숫자 (numbers 모듈에서), 스트림 (io 모듈에서), 임포트 파인더와 로더 (importlib.abc 모듈에서). abc 모듈을 사용해서 자신만의 ABC를 만들 수도 있습니다.

annotate function

A function that can be called to retrieve the annotations of an object. This function is accessible as the __annotate__ attribute of functions, classes, and modules. Annotate functions are a subset of evaluate functions.

annotation (어노테이션)

관습에 따라 형 힌트 로 사용되는 변수, 클래스 어트리뷰트 또는 함수 매개변수 나 반환 값과 연결된 레이블입니다.

Annotations of local variables cannot be accessed at runtime, but annotations of global variables, class attributes, and functions can be retrieved by calling annotationlib.get_annotations() on modules, classes, and functions, respectively.

See variable annotation, function annotation, PEP 484 [https://peps.python.org/pep-0484/], PEP 526 [https://peps.python.org/pep-0526/], and PEP 649 [https://peps.python.org/pep-0649/], which describe this functionality. Also see Annotations Best Practices for best practices on working with annotations.

argument (인자)

함수를 호출할 때 함수 (또는 메서드) 로 전달되는 값. 두 종류의 인자가 있습니다:

키워드 인자 (keyword argument): 함수 호출 때 식별자가 앞에 붙은 인자 (예를 들어, name=) 또는 ** 를 앞에 붙인 딕셔너리로 전달되는 인자. 예를 들어, 다음과 같은 complex() 호출에서 3 과 5 는 모두 키워드 인자입니다:

complex(real=3, imag=5)
complex(**{'real': 3, 'imag': 5})

위치 인자 (positional argument): 키워드 인자가 아닌 인자. 위치 인자들은 인자 목록의 처음에 나오거나 이터러블 의 앞에 * 를 붙여 전달할 수 있습니다. 예를 들어, 다음과 같은 호출에서 3 과 5 는 모두 위치 인자입니다.

complex(3, 5)
complex(*(3, 5))

인자는 함수 바디의 이름 붙은 지역 변수에 대입됩니다. 이 대입에 적용되는 규칙들에 대해서는 호출 절을 보세요. 문법적으로, 어떤 표현식이건 인자로 사용될 수 있습니다; 구해진 값이 지역 변수에 대입됩니다.

용어집의 매개변수 항목과 FAQ 질문 인자와 매개변수의 차이 와 PEP 362 [https://peps.python.org/pep-0362/]도 보세요.

asynchronous context manager (비동기 컨텍스트 관리자)

An object which controls the environment seen in an async with statement by defining __aenter__() and __aexit__() methods. Introduced by PEP 492 [https://peps.python.org/pep-0492/].

asynchronous generator (비동기 제너레이터)

비동기 제너레이터 이터레이터 를 돌려주는 함수. async def 로 정의되는 코루틴 함수처럼 보이는데, async for 루프가 사용할 수 있는 일련의 값들을 만드는 yield 표현식을 포함한다는 점이 다릅니다.

보통 비동기 제너레이터 함수를 가리키지만, 어떤 문맥에서는 비동기 제너레이터 이터레이터 를 가리킵니다. 의도하는 의미가 명확하지 않은 경우는, 완전한 용어를 써서 모호함을 없앱니다.

비동기 제너레이터 함수는 await 표현식과, async for 문과, async with 문을 포함할 수 있습니다.

asynchronous generator iterator (비동기 제너레이터 이터레이터)

비동기 제너레이터 함수가 만드는 객체.

This is an asynchronous iterator which when called using the __anext__() method returns an awaitable object which will execute the body of the asynchronous generator function until the next yield expression.

Each yield temporarily suspends processing, remembering the location execution state (including local variables and pending try-statements). When the asynchronous generator iterator effectively resumes with another awaitable returned by __anext__(), it picks up where it left off. See PEP 492 [https://peps.python.org/pep-0492/] and PEP 525 [https://peps.python.org/pep-0525/].

asynchronous iterable (비동기 이터러블)

An object, that can be used in an async for statement. Must return an asynchronous iterator from its __aiter__() method. Introduced by PEP 492 [https://peps.python.org/pep-0492/].

asynchronous iterator (비동기 이터레이터)

An object that implements the __aiter__() and __anext__() methods. __anext__() must return an awaitable object. async for resolves the awaitables returned by an asynchronous iterator’s __anext__() method until it raises a StopAsyncIteration exception. Introduced by PEP 492 [https://peps.python.org/pep-0492/].

attribute (어트리뷰트)

A value associated with an object which is usually referenced by name using dotted expressions. For example, if an object o has an attribute a it would be referenced as o.a.

It is possible to give an object an attribute whose name is not an identifier as defined by 식별자와 키워드, for example using setattr(), if the object allows it. Such an attribute will not be accessible using a dotted expression, and would instead need to be retrieved with getattr().

awaitable (어웨이터블)

An object that can be used in an await expression. Can be a coroutine or an object with an __await__() method. See also PEP 492 [https://peps.python.org/pep-0492/].

BDFL

자비로운 종신 독재자 (Benevolent Dictator For Life), 즉 Guido van Rossum [https://gvanrossum.github.io/], 파이썬의 창시자.

binary file (바이너리 파일)

A file object able to read and write bytes-like objects. Examples of binary files are files opened in binary mode ('rb', 'wb' or 'rb+'), sys.stdin.buffer, sys.stdout.buffer, and instances of io.BytesIO and gzip.GzipFile.

str 객체를 읽고 쓸 수 있는 파일 객체에 대해서는 텍스트 파일 도 참조하세요.

borrowed reference

In Python’s C API, a borrowed reference is a reference to an object, where the code using the object does not own the reference. It becomes a dangling pointer if the object is destroyed. For example, a garbage collection can remove the last strong reference to the object and so destroy it.

Calling Py_INCREF() on the borrowed reference is recommended to convert it to a strong reference in-place, except when the object cannot be destroyed before the last usage of the borrowed reference. The Py_NewRef() function can be used to create a new strong reference.

bytes-like object (바이트열류 객체)

버퍼 프로토콜 를 지원하고 C-연속 버퍼를 익스포트 할 수 있습니다. 여러 공통 memoryview 객체들은 물론이고 bytes, bytearray, array.array 객체들을 포함합니다. 바이트열류 객체들은 바이너리 데이터를 다루는 여러 가지 연산들에 사용될 수 있습니다; 압축, 바이너리 파일로 저장, 소켓을 통한 전송 같은 것들이 있습니다.

어떤 연산들은 바이너리 데이터가 가변적일 필요가 있습니다. 이런 경우에 설명서는 종종 “읽고-쓰기 바이트열류 객체”라고 표현합니다. 가변 버퍼 객체의 예로는 bytearray 와 bytearray 의 memoryview 가 있습니다. 다른 연산들은 바이너리 데이터가 불변 객체 (“읽기 전용 바이트열류 객체”)에 저장되도록 요구합니다; 이런 것들의 예로는 bytes와 bytes 객체의 memoryview 가 있습니다.

bytecode (바이트 코드)

파이썬 소스 코드는 바이트 코드로 컴파일되는데, CPython 인터프리터에서 파이썬 프로그램의 내부 표현입니다. 바이트 코드는 .pyc 파일에 캐시 되어, 같은 파일을 두 번째 실행할 때 더 빨라지게 만듭니다 (소스에서 바이트 코드로의 재컴파일을 피할 수 있습니다). 이 “중간 언어” 는 각 바이트 코드에 대응하는 기계를 실행하는 가상 기계 에서 실행된다고 말합니다. 바이트 코드는 서로 다른 파이썬 가상 기계에서 작동할 것으로 기대하지도, 파이썬 배포 간에 안정적이지도 않다는 것에 주의해야 합니다.

바이트 코드 명령어들의 목록은 dis 모듈 설명서에 나옵니다.

callable

A callable is an object that can be called, possibly with a set of arguments (see argument), with the following syntax:

callable(argument1, argument2, argumentN)

A function, and by extension a method, is a callable. An instance of a class that implements the __call__() method is also a callable.

callback (콜백)

인자로 전달되는 미래의 어느 시점에서 실행될 서브 루틴 함수.

class (클래스)

사용자 정의 객체들을 만들기 위한 주형. 클래스 정의는 보통 클래스의 인스턴스를 대상으로 연산하는 메서드 정의들을 포함합니다.

class variable (클래스 변수)

클래스에서 정의되고 클래스 수준 (즉, 클래스의 인스턴스에서가 아니라) 에서만 수정되는 변수.

closure variable

A free variable referenced from a nested scope that is defined in an outer scope rather than being resolved at runtime from the globals or builtin namespaces. May be explicitly defined with the nonlocal keyword to allow write access, or implicitly defined if the variable is only being read.

For example, in the inner function in the following code, both x and print are free variables, but only x is a closure variable:

def outer():
    x = 0
    def inner():
        nonlocal x
        x += 1
        print(x)
    return inner

Due to the codeobject.co_freevars attribute (which, despite its name, only includes the names of closure variables rather than listing all referenced free variables), the more general free variable term is sometimes used even when the intended meaning is to refer specifically to closure variables.

complex number (복소수)

익숙한 실수 시스템의 확장인데, 모든 숫자가 실수부와 허수부의 합으로 표현됩니다. 허수부는 실수에 허수 단위(-1의 제곱근)를 곱한 것인데, 종종 수학에서는 i로, 공학에서는 j로 표기합니다. 파이썬은 후자의 표기법을 쓰는 복소수를 기본 지원합니다; 허수부는 j 접미사를 붙여서 표기합니다, 예를 들어, 3+1j. math 모듈의 복소수 버전이 필요하면, cmath를 사용합니다. 복소수의 활용은 꽤 수준 높은 수학적 기능입니다. 필요하다고 느끼지 못한다면, 거의 확실히 무시해도 좋습니다.

context

This term has different meanings depending on where and how it is used. Some common meanings:

The temporary state or environment established by a context manager via a with statement.

The collection of keyvalue bindings associated with a particular contextvars.Context object and accessed via ContextVar objects. Also see context variable.

A contextvars.Context object. Also see current context.

context management protocol

The __enter__() and __exit__() methods called by the with statement. See PEP 343 [https://peps.python.org/pep-0343/].

context manager (컨텍스트 관리자)

An object which implements the context management protocol and controls the environment seen in a with statement. See PEP 343 [https://peps.python.org/pep-0343/].

context variable (컨텍스트 변수)

A variable whose value depends on which context is the current context. Values are accessed via contextvars.ContextVar objects. Context variables are primarily used to isolate state between concurrent asynchronous tasks.

contiguous (연속)

버퍼는 정확히 C-연속(C-contiguous)이거나 포트란 연속(Fortran contiguous)일 때 연속이라고 여겨집니다. 영차원 버퍼는 C-연속이면서 포트란 연속입니다. 일차원 배열에서, 항목들은 서로에 인접하고, 0에서 시작하는 오름차순 인덱스의 순서대로 메모리에 배치되어야 합니다. 다차원 C-연속 배열에서, 메모리 주소의 순서대로 항목들을 방문할 때 마지막 인덱스가 가장 빨리 변합니다. 하지만, 포트란 연속 배열에서는, 첫 번째 인덱스가 가장 빨리 변합니다.

coroutine (코루틴)

코루틴은 서브루틴의 더 일반화된 형태입니다. 서브루틴은 한 지점에서 진입하고 다른 지점에서 탈출합니다. 코루틴은 여러 다른 지점에서 진입하고, 탈출하고, 재개할 수 있습니다. 이것들은 async def 문으로 구현할 수 있습니다. PEP 492 [https://peps.python.org/pep-0492/]를 보세요.

coroutine function (코루틴 함수)

코루틴 객체를 돌려주는 함수. 코루틴 함수는 async def 문으로 정의될 수 있고, await 와 async for와 async with 키워드를 포함할 수 있습니다. 이것들은 PEP 492 [https://peps.python.org/pep-0492/] 에 의해 도입되었습니다.

CPython

파이썬 프로그래밍 언어의 규범적인 구현인데, python.org [https://www.python.org]에서 배포됩니다. 이 구현을 Jython 이나 IronPython 과 같은 다른 것들과 구별할 필요가 있을 때 용어 “CPython” 이 사용됩니다.

current context

The context (contextvars.Context object) that is currently used by ContextVar objects to access (get or set) the values of context variables. Each thread has its own current context. Frameworks for executing asynchronous tasks (see asyncio) associate each task with a context which becomes the current context whenever the task starts or resumes execution.

decorator (데코레이터)

다른 함수를 돌려주는 함수인데, 보통 @wrapper 문법을 사용한 함수 변환으로 적용됩니다. 데코레이터의 흔한 예는 classmethod() 과 staticmethod() 입니다.

데코레이터 문법은 단지 편의 문법일 뿐입니다. 다음 두 함수 정의는 의미상으로 동등합니다:

def f(arg):
    ...
f = staticmethod(f)

@staticmethod
def f(arg):
    ...

같은 개념이 클래스에도 존재하지만, 덜 자주 쓰입니다. 데코레이터에 대한 더 자세한 내용은 함수 정의 와 클래스 정의 의 설명서를 보면 됩니다.

descriptor (디스크립터)

Any object which defines the methods __get__(), __set__(), or __delete__(). When a class attribute is a descriptor, its special binding behavior is triggered upon attribute lookup. Normally, using a.b to get, set or delete an attribute looks up the object named b in the class dictionary for a, but if b is a descriptor, the respective descriptor method gets called. Understanding descriptors is a key to a deep understanding of Python because they are the basis for many features including functions, methods, properties, class methods, static methods, and reference to super classes.

디스크립터의 메서드들에 대한 자세한 내용은 디스크립터 구현하기나 디스크립터 사용법 안내서에 나옵니다.

dictionary (딕셔너리)

An associative array, where arbitrary keys are mapped to values. The keys can be any object with __hash__() and __eq__() methods. Called a hash in Perl.

dictionary comprehension (딕셔너리 컴프리헨션)

이터러블에 있는 요소 전체나 일부를 처리하고 결과를 담은 딕셔너리를 반환하는 간결한 방법. results = {n: n ** 2 for n in range(10)}은 값 n ** 2에 매핑된 키 n을 포함하는 딕셔너리를 생성합니다. 리스트, 집합, 딕셔너리의 디스플레이(display)을 참조하십시오.

dictionary view (딕셔너리 뷰)

dict.keys(), dict.values(), dict.items() 메서드가 돌려주는 객체들을 딕셔너리 뷰라고 부릅니다. 이것들은 딕셔너리 항목들에 대한 동적인 뷰를 제공하는데, 딕셔너리가 변경될 때, 뷰가 이 변화를 반영한다는 뜻입니다. 딕셔너리 뷰를 완전한 리스트로 바꾸려면 list(dictview)를 사용하면 됩니다. 딕셔너리 뷰 객체를 보세요.

docstring (독스트링)

A string literal which appears as the first expression in a class, function or module. While ignored when the suite is executed, it is recognized by the compiler and put into the __doc__ attribute of the enclosing class, function or module. Since it is available via introspection, it is the canonical place for documentation of the object.

duck-typing (덕 타이핑)

올바른 인터페이스를 가졌는지 판단하는데 객체의 형을 보지 않는 프로그래밍 스타일; 대신, 단순히 메서드나 어트리뷰트가 호출되거나 사용됩니다 (“오리처럼 보이고 오리처럼 꽥꽥댄다면, 그것은 오리다.”) 특정한 형 대신에 인터페이스를 강조함으로써, 잘 설계된 코드는 다형적인 치환을 허락함으로써 유연성을 개선할 수 있습니다. 덕 타이핑은 type() 이나 isinstance() 을 사용한 검사를 피합니다. (하지만, 덕 타이핑이 추상 베이스 클래스 로 보완될 수 있음에 유의해야 합니다.) 대신에, hasattr() 검사나 EAFP 프로그래밍을 씁니다.

EAFP

허락보다는 용서를 구하기가 쉽다 (Easier to ask for forgiveness than permission). 이 흔히 볼 수 있는 파이썬 코딩 스타일은, 올바른 키나 어트리뷰트의 존재를 가정하고, 그 가정이 틀리면 예외를 잡습니다. 이 깔끔하고 빠른 스타일은 많은 try와 except 문의 존재로 특징지어집니다. 이 테크닉은 C와 같은 다른 많은 언어에서 자주 사용되는 LBYL 스타일과 대비됩니다.

evaluate function

A function that can be called to evaluate a lazily evaluated attribute of an object, such as the value of type aliases created with the type statement.

expression (표현식)

어떤 값으로 구해질 수 있는 문법적인 조각. 다른 말로 표현하면, 표현식은 리터럴, 이름, 어트리뷰트 액세스, 연산자, 함수들과 같은 값을 돌려주는 표현 요소들을 쌓아 올린 것입니다. 다른 많은 언어와 대조적으로, 모든 언어 구성물들이 표현식인 것은 아닙니다. while처럼, 표현식으로 사용할 수 없는 문장 들이 있습니다. 대입 또한 문장이고, 표현식이 아닙니다.

extension module (확장 모듈)

C 나 C++로 작성된 모듈인데, 파이썬의 C API를 사용해서 핵심이나 사용자 코드와 상호 작용합니다.

f-string (f-문자열)

'f' 나 'F' 를 앞에 붙인 문자열 리터럴들을 흔히 “f-문자열”이라고 부르는데, 포맷 문자열 리터럴 의 줄임말입니다. PEP 498 [https://peps.python.org/pep-0498/] 을 보세요.

file object (파일 객체)

An object exposing a file-oriented API (with methods such as read() or write()) to an underlying resource. Depending on the way it was created, a file object can mediate access to a real on-disk file or to another type of storage or communication device (for example standard input/output, in-memory buffers, sockets, pipes, etc.). File objects are also called file-like objects or streams.

실제로는 세 부류의 파일 객체들이 있습니다. 날(raw) 바이너리 파일, 버퍼드(buffered) 바이너리 파일, 텍스트 파일. 이들의 인터페이스는 io 모듈에서 정의됩니다. 파일 객체를 만드는 규범적인 방법은 open() 함수를 쓰는 것입니다.

file-like object (파일류 객체)

파일 객체 의 비슷한 말.

filesystem encoding and error handler

Encoding and error handler used by Python to decode bytes from the operating system and encode Unicode to the operating system.

The filesystem encoding must guarantee to successfully decode all bytes below 128. If the file system encoding fails to provide this guarantee, API functions can raise UnicodeError.

The sys.getfilesystemencoding() and sys.getfilesystemencodeerrors() functions can be used to get the filesystem encoding and error handler.

The filesystem encoding and error handler are configured at Python startup by the PyConfig_Read() function: see filesystem_encoding and filesystem_errors members of PyConfig.

See also the locale encoding.

finder (파인더)

임포트될 모듈을 위한 로더 를 찾으려고 시도하는 객체.

There are two types of finder: meta path finders for use with sys.meta_path, and path entry finders for use with sys.path_hooks.

See 파인더(finder)와 로더(loader) and importlib for much more detail.

floor division (정수 나눗셈)

가장 가까운 정수로 내림하는 수학적 나눗셈. 정수 나눗셈 연산자는 // 다. 예를 들어, 표현식 11 // 4 의 값은 2가 되지만, 실수 나눗셈은 2.75를 돌려줍니다. (-11) // 4 가 -2.75를 내림 한 -3이 됨에 유의해야 합니다. PEP 238 [https://peps.python.org/pep-0238/]을 보세요.

free threading

A threading model where multiple threads can run Python bytecode simultaneously within the same interpreter. This is in contrast to the global interpreter lock which allows only one thread to execute Python bytecode at a time. See PEP 703 [https://peps.python.org/pep-0703/].

free variable

Formally, as defined in the language execution model, a free variable is any variable used in a namespace which is not a local variable in that namespace. See closure variable for an example. Pragmatically, due to the name of the codeobject.co_freevars attribute, the term is also sometimes used as a synonym for closure variable.

function (함수)

호출자에게 어떤 값을 돌려주는 일련의 문장들. 없거나 그 이상의 인자 가 전달될 수 있는데, 바디의 실행에 사용될 수 있습니다. 매개변수 와 메서드 와 함수 정의 섹션도 보세요.

function annotation (함수 어노테이션)

함수 매개변수나 반환 값의 어노테이션.

함수 어노테이션은 일반적으로 형 힌트 로 사용됩니다: 예를 들어, 이 함수는 두 개의 int 인자를 받아들일 것으로 기대되고, 동시에 int 반환 값을 줄 것으로 기대됩니다:

def sum_two_numbers(a: int, b: int) -> int:
   return a + b

함수 어노테이션 문법은 함수 정의 절에서 설명합니다.

See variable annotation and PEP 484 [https://peps.python.org/pep-0484/], which describe this functionality. Also see Annotations Best Practices for best practices on working with annotations.

__future__

A future statement, from __future__ import <feature>, directs the compiler to compile the current module using syntax or semantics that will become standard in a future release of Python. The __future__ module documents the possible values of feature. By importing this module and evaluating its variables, you can see when a new feature was first added to the language and when it will (or did) become the default:

>>> import __future__
>>> __future__.division
_Feature((2, 2, 0, 'alpha', 2), (3, 0, 0, 'alpha', 0), 8192)

garbage collection (가비지 수거)

더 사용되지 않는 메모리를 반납하는 절차. 파이썬은 참조 횟수 추적과 참조 순환을 감지하고 끊을 수 있는 순환 가비지 수거기를 통해 가비지 수거를 수행합니다. 가비지 수거기는 gc 모듈을 사용해서 제어할 수 있습니다.

generator (제너레이터)

제너레이터 이터레이터 를 돌려주는 함수. 일반 함수처럼 보이는데, 일련의 값들을 만드는 yield 표현식을 포함한다는 점이 다릅니다. 이 값들은 for-루프로 사용하거나 next() 함수로 한 번에 하나씩 꺼낼 수 있습니다.

보통 제너레이터 함수를 가리키지만, 어떤 문맥에서는 제너레이터 이터레이터 를 가리킵니다. 의도하는 의미가 명확하지 않은 경우는, 완전한 용어를 써서 모호함을 없앱니다.

generator iterator (제너레이터 이터레이터)

제너레이터 함수가 만드는 객체.

각 yield는 일시적으로 처리를 중단하고, 그 위치의 (지역 변수들과 대기 중인 try-문들을 포함하는) 실행 상태를 기억합니다. 제너레이터 이터레이터 가 재개되면, 떠난 곳으로 복귀합니다 (호출마다 새로 시작하는 함수와 대비됩니다).

generator expression (제너레이터 표현식)

An expression that returns an iterator. It looks like a normal expression followed by a for clause defining a loop variable, range, and an optional if clause. The combined expression generates values for an enclosing function:

>>> sum(i*i for i in range(10))         # sum of squares 0, 1, 4, ... 81
285

generic function (제네릭 함수)

같은 연산을 서로 다른 형들에 대해 구현한 여러 함수로 구성된 함수. 호출 때 어떤 구현이 사용될지는 디스패치 알고리즘에 의해 결정됩니다.

싱글 디스패치 용어집 항목과 functools.singledispatch() 데코레이터와 PEP 443 [https://peps.python.org/pep-0443/]도 보세요.

generic type (제네릭 형)

A type that can be parameterized; typically a container class such as list or dict. Used for type hints and annotations.

For more details, see generic alias types, PEP 483 [https://peps.python.org/pep-0483/], PEP 484 [https://peps.python.org/pep-0484/], PEP 585 [https://peps.python.org/pep-0585/], and the typing module.

GIL

전역 인터프리터 록 을 보세요.

global interpreter lock (전역 인터프리터 록)

한 번에 오직 하나의 스레드가 파이썬 바이트 코드 를 실행하도록 보장하기 위해 CPython 인터프리터가 사용하는 메커니즘. (dict와 같은 중요한 내장형들을 포함하는) 객체 모델이 묵시적으로 동시 액세스에 대해 안전하도록 만들어서 CPython 구현을 단순하게 만듭니다. 인터프리터 전체를 잠그는 것은 인터프리터를 다중스레드화하기 쉽게 만드는 대신, 다중 프로세서 기계가 제공하는 병렬성의 많은 부분을 희생합니다.

However, some extension modules, either standard or third-party, are designed so as to release the GIL when doing computationally intensive tasks such as compression or hashing. Also, the GIL is always released when doing I/O.

As of Python 3.13, the GIL can be disabled using the --disable-gil build configuration. After building Python with this option, code must be run with -X gil=0 or after setting the PYTHON_GIL=0 environment variable. This feature enables improved performance for multi-threaded applications and makes it easier to use multi-core CPUs efficiently. For more details, see PEP 703 [https://peps.python.org/pep-0703/].

hash-based pyc (해시 기반 pyc)

유효성을 판별하기 위해 해당 소스 파일의 최종 수정 시간이 아닌 해시를 사용하는 바이트 코드 캐시 파일. 캐시된 바이트 코드 무효화을 참조하세요.

hashable (해시 가능)

An object is hashable if it has a hash value which never changes during its lifetime (it needs a __hash__() method), and can be compared to other objects (it needs an __eq__() method). Hashable objects which compare equal must have the same hash value.

해시 가능성은 객체를 딕셔너리의 키나 집합의 멤버로 사용할 수 있게 하는데, 이 자료 구조들이 내부적으로 해시값을 사용하기 때문입니다.

대부분 파이썬의 불변 내장 객체들은 해시 가능합니다; (리스트나 딕셔너리 같은) 가변 컨테이너들은 그렇지 않습니다; (튜플이나 frozenset 같은) 불변 컨테이너들은 그들의 요소들이 해시 가능할 때만 해시 가능합니다. 사용자 정의 클래스의 인스턴스 객체들은 기본적으로 해시 가능합니다. (자기 자신을 제외하고는) 모두 다르다고 비교되고, 해시값은 id()로 부터 만들어집니다.

IDLE

An Integrated Development and Learning Environment for Python. IDLE is a basic editor and interpreter environment which ships with the standard distribution of Python.

immortal

Immortal objects are a CPython implementation detail introduced in PEP 683 [https://peps.python.org/pep-0683/].

If an object is immortal, its reference count is never modified, and therefore it is never deallocated while the interpreter is running. For example, True and None are immortal in CPython.

immutable (불변)

고정된 값을 갖는 객체. 불변 객체는 숫자, 문자열, 튜플을 포함합니다. 이런 객체들은 변경될 수 없습니다. 새 값을 저장하려면 새 객체를 만들어야 합니다. 변하지 않는 해시값이 있어야 하는 곳에서 중요한 역할을 합니다, 예를 들어, 딕셔너리의 키.

import path (임포트 경로)

경로 기반 파인더 가 임포트 할 모듈을 찾기 위해 검색하는 장소들 (또는 경로 엔트리) 의 목록. 임포트 하는 동안, 이 장소들의 목록은 보통 sys.path 로부터 옵니다, 하지만 서브 패키지의 경우 부모 패키지의 __path__ 어트리뷰트로부터 올 수도 있습니다.

importing (임포팅)

한 모듈의 파이썬 코드가 다른 모듈의 파이썬 코드에서 사용될 수 있도록 하는 절차.

importer (임포터)

모듈을 찾기도 하고 로드 하기도 하는 객체; 동시에 파인더 이자 로더 객체입니다.

interactive (대화형)

Python has an interactive interpreter which means you can enter statements and expressions at the interpreter prompt, immediately execute them and see their results. Just launch python with no arguments (possibly by selecting it from your computer’s main menu). It is a very powerful way to test out new ideas or inspect modules and packages (remember help(x)). For more on interactive mode, see 대화형 모드.

interpreted (인터프리티드)

바이트 코드 컴파일러의 존재 때문에 그 구분이 흐릿해지기는 하지만, 파이썬은 컴파일 언어가 아니라 인터프리터 언어입니다. 이것은 명시적으로 실행 파일을 만들지 않고도, 소스 파일을 직접 실행할 수 있다는 뜻입니다. 그 프로그램이 좀 더 천천히 실행되기는 하지만, 인터프리터 언어는 보통 컴파일 언어보다 짧은 개발/디버깅 주기를 갖습니다. 대화형 도 보세요.

interpreter shutdown (인터프리터 종료)

종료하라는 요청을 받을 때, 파이썬 인터프리터는 특별한 시기에 진입하는데, 모듈이나 여러 가지 중요한 내부 구조들과 같은 모든 할당된 자원들을 단계적으로 반납합니다. 또한, 가비지 수거기 를 여러 번 호출합니다. 사용자 정의 파괴자나 weakref 콜백에 있는 코드들의 실행을 시작시킬 수 있습니다. 종료 시기 동안 실행되는 코드는 다양한 예외들을 만날 수 있는데, 그것이 의존하는 자원들이 더 기능하지 않을 수 있기 때문입니다 (흔한 예는 라이브러리 모듈이나 경고 장치들입니다).

인터프리터 종료의 주된 원인은 실행되는 __main__ 모듈이나 스크립트가 실행을 끝내는 것입니다.

iterable (이터러블)

An object capable of returning its members one at a time. Examples of iterables include all sequence types (such as list, str, and tuple) and some non-sequence types like dict, file objects, and objects of any classes you define with an __iter__() method or with a __getitem__() method that implements sequence semantics.

Iterables can be used in a for loop and in many other places where a sequence is needed (zip(), map(), …). When an iterable object is passed as an argument to the built-in function iter(), it returns an iterator for the object. This iterator is good for one pass over the set of values. When using iterables, it is usually not necessary to call iter() or deal with iterator objects yourself. The for statement does that automatically for you, creating a temporary unnamed variable to hold the iterator for the duration of the loop. See also iterator, sequence, and generator.

iterator (이터레이터)

An object representing a stream of data. Repeated calls to the iterator’s __next__() method (or passing it to the built-in function next()) return successive items in the stream. When no more data are available a StopIteration exception is raised instead. At this point, the iterator object is exhausted and any further calls to its __next__() method just raise StopIteration again. Iterators are required to have an __iter__() method that returns the iterator object itself so every iterator is also iterable and may be used in most places where other iterables are accepted. One notable exception is code which attempts multiple iteration passes. A container object (such as a list) produces a fresh new iterator each time you pass it to the iter() function or use it in a for loop. Attempting this with an iterator will just return the same exhausted iterator object used in the previous iteration pass, making it appear like an empty container.

이터레이터 형 에 더 자세한 내용이 있습니다.

CPython 구현 상세: CPython does not consistently apply the requirement that an iterator define __iter__(). And also please note that the free-threading CPython does not guarantee the thread-safety of iterator operations.

key function (키 함수)

키 함수 또는 콜레이션(collation) 함수는 정렬(sorting)이나 배열(ordering)에 사용되는 값을 돌려주는 콜러블입니다. 예를 들어, locale.strxfrm() 은 로케일 특정 방식을 따르는 정렬 키를 만드는 데 사용됩니다.

파이썬의 많은 도구가 요소들이 어떻게 순서 지어지고 묶이는지를 제어하기 위해 키 함수를 받아들입니다. 이런 것들에는 min(), max(), sorted(), list.sort(), heapq.merge(), heapq.nsmallest(), heapq.nlargest(), itertools.groupby() 이 있습니다.

There are several ways to create a key function. For example. the str.lower() method can serve as a key function for case insensitive sorts. Alternatively, a key function can be built from a lambda expression such as lambda r: (r[0], r[2]). Also, operator.attrgetter(), operator.itemgetter(), and operator.methodcaller() are three key function constructors. See the Sorting HOW TO for examples of how to create and use key functions.

keyword argument (키워드 인자)

인자 를 보세요.

lambda (람다)

호출될 때 값이 구해지는 하나의 표현식 으로 구성된 이름 없는 인라인 함수. 람다 함수를 만드는 문법은 lambda [parameters]: expression 입니다.

LBYL

뛰기 전에 보라 (Look before you leap). 이 코딩 스타일은 호출이나 조회를 하기 전에 명시적으로 사전 조건들을 검사합니다. 이 스타일은 EAFP 접근법과 대비되고, 많은 if 문의 존재로 특징지어집니다.

다중 스레드 환경에서, LBYL 접근법은 “보기”와 “뛰기” 간에 경쟁 조건을 만들게 될 위험이 있습니다. 예를 들어, 코드 if key in mapping: return mapping[key] 는 검사 후에, 하지만 조회 전에, 다른 스레드가 key를 mapping에서 제거하면 실패할 수 있습니다. 이런 이슈는 록이나 EAFP 접근법을 사용함으로써 해결될 수 있습니다.

list (리스트)

A built-in Python sequence. Despite its name it is more akin to an array in other languages than to a linked list since access to elements is O(1).

list comprehension (리스트 컴프리헨션)

시퀀스의 요소들 전부 또는 일부를 처리하고 그 결과를 리스트로 돌려주는 간결한 방법. result = ['{:#04x}'.format(x) for x in range(256) if x % 2 == 0] 는 0에서 255 사이에 있는 짝수들의 16진수 (0x..) 들을 포함하는 문자열의 리스트를 만듭니다. if 절은 생략할 수 있습니다. 생략하면, range(256)에 있는 모든 요소가 처리됩니다.

loader (로더)

An object that loads a module. It must define a method named load_module(). A loader is typically returned by a finder. See also:

파인더(finder)와 로더(loader)

importlib.abc.Loader

PEP 302 [https://peps.python.org/pep-0302/]

locale encoding

On Unix, it is the encoding of the LC_CTYPE locale. It can be set with locale.setlocale(locale.LC_CTYPE, new_locale).

On Windows, it is the ANSI code page (ex: "cp1252").

On Android and VxWorks, Python uses "utf-8" as the locale encoding.

locale.getencoding() can be used to get the locale encoding.

See also the filesystem encoding and error handler.

magic method (매직 메서드)

특수 메서드 의 비공식적인 비슷한 말.

mapping (매핑)

A container object that supports arbitrary key lookups and implements the methods specified in the collections.abc.Mapping or collections.abc.MutableMapping abstract base classes. Examples include dict, collections.defaultdict, collections.OrderedDict and collections.Counter.

meta path finder (메타 경로 파인더)

sys.meta_path 의 검색이 돌려주는 파인더. 메타 경로 파인더는 경로 엔트리 파인더 와 관련되어 있기는 하지만 다릅니다.

메타 경로 파인더가 구현하는 메서드들에 대해서는 importlib.abc.MetaPathFinder 를 보면 됩니다.

metaclass (메타 클래스)

클래스의 클래스. 클래스 정의는 클래스 이름, 클래스 딕셔너리, 베이스 클래스들의 목록을 만듭니다. 메타 클래스는 이 세 인자를 받아서 클래스를 만드는 책임을 집니다. 대부분의 객체 지향형 프로그래밍 언어들은 기본 구현을 제공합니다. 파이썬을 특별하게 만드는 것은 커스텀 메타 클래스를 만들 수 있다는 것입니다. 대부분 사용자에게는 이 도구가 전혀 필요 없지만, 필요가 생길 때, 메타 클래스는 강력하고 우아한 해법을 제공합니다. 어트리뷰트 액세스의 로깅(logging), 스레드 안전성의 추가, 객체 생성 추적, 싱글톤 구현과 많은 다른 작업에 사용됐습니다.

메타 클래스 에서 더 자세한 내용을 찾을 수 있습니다.

method (메서드)

클래스 바디 안에서 정의되는 함수. 그 클래스의 인스턴스의 어트리뷰트로서 호출되면, 그 메서드는 첫 번째 인자 (보통 self 라고 불린다) 로 인스턴스 객체를 받습니다. 함수 와 중첩된 스코프 를 보세요.

method resolution order (메서드 결정 순서)

Method Resolution Order is the order in which base classes are searched for a member during lookup. See The Python 2.3 Method Resolution Order for details of the algorithm used by the Python interpreter since the 2.3 release.

module (모듈)

파이썬 코드의 조직화 단위를 담당하는 객체. 모듈은 임의의 파이썬 객체들을 담는 이름 공간을 갖습니다. 모듈은 임포팅 절차에 의해 파이썬으로 로드됩니다.

패키지 도 보세요.

module spec (모듈 스펙)

모듈을 로드하는데 사용되는 임포트 관련 정보들을 담고 있는 이름 공간. importlib.machinery.ModuleSpec 의 인스턴스.

See also Module specs.

MRO

메서드 결정 순서 를 보세요.

mutable (가변)

가변 객체는 값이 변할 수 있지만 id() 는 일정하게 유지합니다. 불변 도 보세요.

named tuple (네임드 튜플)

“named tuple(네임드 튜플)”이라는 용어는 튜플에서 상속하고 이름 붙은 어트리뷰트를 사용하여 인덱스 할 수 있는 요소에 액세스 할 수 있는 모든 형이나 클래스에 적용됩니다. 형이나 클래스에는 다른 기능도 있을 수 있습니다.

time.localtime()과 os.stat()가 반환한 값을 포함하여, 여러 내장형이 네임드 튜플입니다. 또 다른 예는 sys.float_info입니다:

>>> sys.float_info[1]                   # indexed access
1024
>>> sys.float_info.max_exp              # named field access
1024
>>> isinstance(sys.float_info, tuple)   # kind of tuple
True

Some named tuples are built-in types (such as the above examples). Alternatively, a named tuple can be created from a regular class definition that inherits from tuple and that defines named fields. Such a class can be written by hand, or it can be created by inheriting typing.NamedTuple, or with the factory function collections.namedtuple(). The latter techniques also add some extra methods that may not be found in hand-written or built-in named tuples.

namespace (이름 공간)

변수가 저장되는 장소. 이름 공간은 딕셔너리로 구현됩니다. 객체에 중첩된 이름 공간 (메서드 에서) 뿐만 아니라 지역, 전역, 내장 이름 공간이 있습니다. 이름 공간은 이름 충돌을 방지해서 모듈성을 지원합니다. 예를 들어, 함수 builtins.open 과 os.open() 은 그들의 이름 공간에 의해 구별됩니다. 또한, 이름 공간은 어떤 모듈이 함수를 구현하는지를 분명하게 만들어서 가독성과 유지 보수성에 도움을 줍니다. 예를 들어, random.seed() 또는 itertools.islice() 라고 쓰면 그 함수들이 각각 random 과 itertools 모듈에 의해 구현되었음이 명확해집니다.

namespace package (이름 공간 패키지)

오직 서브 패키지들의 컨테이너로만 기능하는 PEP 420 [https://peps.python.org/pep-0420/] 패키지. 이름 공간 패키지는 물리적인 실체가 없을 수도 있고, 특히 __init__.py 파일이 없으므로 정규 패키지 와는 다릅니다.

모듈 도 보세요.

nested scope (중첩된 스코프)

둘러싼 정의에서 변수를 참조하는 능력. 예를 들어, 다른 함수 내부에서 정의된 함수는 바깥 함수에 있는 변수들을 참조할 수 있습니다. 중첩된 스코프는 기본적으로는 참조만 가능할 뿐, 대입은 되지 않는다는 것에 주의해야 합니다. 지역 변수들은 가장 내부의 스코프에서 읽고 씁니다. 마찬가지로, 전역 변수들은 전역 이름 공간에서 읽고 씁니다. nonlocal 은 바깥 스코프에 쓰는 것을 허락합니다.

new-style class (뉴스타일 클래스)

Old name for the flavor of classes now used for all class objects. In earlier Python versions, only new-style classes could use Python’s newer, versatile features like __slots__, descriptors, properties, __getattribute__(), class methods, and static methods.

object (객체)

상태 (어트리뷰트나 값) 를 갖고 동작 (메서드) 이 정의된 모든 데이터. 또한, 모든 뉴스타일 클래스 의 최종적인 베이스 클래스입니다.

optimized scope

A scope where target local variable names are reliably known to the compiler when the code is compiled, allowing optimization of read and write access to these names. The local namespaces for functions, generators, coroutines, comprehensions, and generator expressions are optimized in this fashion. Note: most interpreter optimizations are applied to all scopes, only those relying on a known set of local and nonlocal variable names are restricted to optimized scopes.

package (패키지)

A Python module which can contain submodules or recursively, subpackages. Technically, a package is a Python module with a __path__ attribute.

정규 패키지 와 이름 공간 패키지 도 보세요.

parameter (매개변수)

함수 (또는 메서드) 정의에서 함수가 받을 수 있는 인자 (또는 어떤 경우 인자들) 를 지정하는 이름 붙은 엔티티. 다섯 종류의 매개변수가 있습니다:

위치-키워드 (positional-or-keyword): 위치 인자 나 키워드 인자 로 전달될 수 있는 인자를 지정합니다. 이것이 기본 형태의 매개변수입니다, 예를 들어 다음에서 foo 와 bar:

def func(foo, bar=None): ...

위치-전용 (positional-only): 위치로만 제공될 수 있는 인자를 지정합니다. 위치 전용 매개변수는 함수 정의의 매개변수 목록에 / 문자를 포함하고 그 뒤에 정의할 수 있습니다, 예를 들어 다음에서 posonly1과 posonly2:

def func(posonly1, posonly2, /, positional_or_keyword): ...

키워드-전용 (keyword-only): 키워드로만 제공될 수 있는 인자를 지정합니다. 키워드-전용 매개변수는 함수 정의의 매개변수 목록에서 앞에 하나의 가변-위치 매개변수나 *를 그대로 포함해서 정의할 수 있습니다. 예를 들어, 다음에서 kw_only1 와 kw_only2:

def func(arg, *, kw_only1, kw_only2): ...

가변-위치 (var-positional): (다른 매개변수들에 의해서 이미 받아들여진 위치 인자들에 더해) 제공될 수 있는 위치 인자들의 임의의 시퀀스를 지정합니다. 이런 매개변수는 매개변수 이름에 * 를 앞에 붙여서 정의될 수 있습니다, 예를 들어 다음에서 args:

def func(*args, **kwargs): ...

가변-키워드 (var-keyword): (다른 매개변수들에 의해서 이미 받아들여진 키워드 인자들에 더해) 제공될 수 있는 임의의 개수 키워드 인자들을 지정합니다. 이런 매개변수는 매개변수 이름에 **를 앞에 붙여서 정의될 수 있습니다, 예를 들어 위의 예에서 kwargs.

매개변수는 선택적 인자들을 위한 기본값뿐만 아니라 선택적이거나 필수 인자들을 지정할 수 있습니다.

인자 용어집 항목, 인자와 매개변수의 차이에 나오는 FAQ 질문, inspect.Parameter 클래스, 함수 정의 절, PEP 362 [https://peps.python.org/pep-0362/]도 보세요.

path entry (경로 엔트리)

경로 기반 파인더 가 임포트 할 모듈들을 찾기 위해 참고하는 임포트 경로 상의 하나의 장소.

path entry finder (경로 엔트리 파인더)

sys.path_hooks 에 있는 콜러블 (즉, 경로 엔트리 훅) 이 돌려주는 파인더 인데, 주어진 경로 엔트리 로 모듈을 찾는 방법을 알고 있습니다.

경로 엔트리 파인더들이 구현하는 메서드들은 importlib.abc.PathEntryFinder 에 나옵니다.

path entry hook (경로 엔트리 훅)

A callable on the sys.path_hooks list which returns a path entry finder if it knows how to find modules on a specific path entry.

path based finder (경로 기반 파인더)

기본 메타 경로 파인더들 중 하나인데, 임포트 경로 에서 모듈을 찾습니다.

path-like object (경로류 객체)

파일 시스템 경로를 나타내는 객체. 경로류 객체는 경로를 나타내는 str 나 bytes 객체이거나 os.PathLike 프로토콜을 구현하는 객체입니다. os.PathLike 프로토콜을 지원하는 객체는 os.fspath() 함수를 호출해서 str 나 bytes 파일 시스템 경로로 변환될 수 있습니다; 대신 os.fsdecode() 와 os.fsencode() 는 각각 str 나 bytes 결과를 보장하는데 사용될 수 있습니다. PEP 519 [https://peps.python.org/pep-0519/]로 도입되었습니다.

PEP

파이썬 개선 제안. PEP는 파이썬 커뮤니티에 정보를 제공하거나 파이썬 또는 그 프로세스 또는 환경에 대한 새로운 기능을 설명하는 설계 문서입니다. PEP는 제안된 기능에 대한 간결한 기술 사양 및 근거를 제공해야 합니다.

PEP는 주요 새로운 기능을 제안하고 문제에 대한 커뮤니티 입력을 수집하며 파이썬에 들어간 설계 결정을 문서로 만들기 위한 기본 메커니즘입니다. PEP 작성자는 커뮤니티 내에서 합의를 구축하고 반대 의견을 문서화 할 책임이 있습니다.

PEP 1 [https://peps.python.org/pep-0001/] 참조하세요.

portion (포션)

PEP 420 [https://peps.python.org/pep-0420/] 에서 정의한 것처럼, 이름 공간 패키지에 이바지하는 하나의 디렉터리에 들어있는 파일들의 집합 (zip 파일에 저장되는 것도 가능합니다).

positional argument (위치 인자)

인자 를 보세요.

provisional API (잠정 API)

잠정 API는 표준 라이브러리의 과거 호환성 보장으로부터 신중히 제외된 것입니다. 인터페이스의 큰 변화가 예상되지는 않지만, 잠정적이라고 표시되는 한, 코어 개발자들이 필요하다고 생각한다면 과거 호환성이 유지되지 않는 변경이 일어날 수 있습니다. 그런 변경은 불필요한 방식으로 일어나지는 않을 것입니다 — API를 포함하기 전에 놓친 중대하고 근본적인 결함이 발견된 경우에만 일어날 것입니다.

잠정 API에서조차도, 과거 호환성이 유지되지 않는 변경은 “최후의 수단”으로 여겨집니다 - 모든 식별된 문제들에 대해 과거 호환성을 유지하는 해법을 찾으려는 모든 시도가 선행됩니다.

이 절차는 표준 라이브러리가 오랜 시간 동안 잘못된 설계 오류에 발목 잡히지 않고 발전할 수 있도록 만듭니다. 더 자세한 내용은 PEP 411 [https://peps.python.org/pep-0411/]을 보면 됩니다.

provisional package (잠정 패키지)

잠정 API 를 보세요.

Python 3000 (파이썬 3000)

파이썬 3.x 배포 라인의 별명 (버전 3의 배포가 먼 미래의 이야기던 시절에 만들어진 이름이다.) 이것을 “Py3k” 로 줄여 쓰기도 합니다.

Pythonic (파이썬다운)

다른 언어들에서 일반적인 개념들을 사용해서 코드를 구현하는 대신, 파이썬 언어에서 가장 자주 사용되는 이디엄들을 가까이 따르는 아이디어나 코드 조각. 예를 들어, 파이썬에서 자주 쓰는 이디엄은 for 문을 사용해서 이터러블의 모든 요소로 루핑하는 것입니다. 다른 많은 언어에는 이런 종류의 구성물이 없으므로, 파이썬에 익숙하지 않은 사람들은 대신에 숫자 카운터를 사용하기도 합니다:

for i in range(len(food)):
    print(food[i])

더 깔끔한, 파이썬다운 방법은 이렇습니다:

for piece in food:
    print(piece)

qualified name (정규화된 이름)

모듈의 전역 스코프에서 모듈에 정의된 클래스, 함수, 메서드에 이르는 “경로”를 보여주는 점으로 구분된 이름. PEP 3155 [https://peps.python.org/pep-3155/] 에서 정의됩니다. 최상위 함수와 클래스의 경우에, 정규화된 이름은 객체의 이름과 같습니다:

>>> class C:
...     class D:
...         def meth(self):
...             pass
...
>>> C.__qualname__
'C'
>>> C.D.__qualname__
'C.D'
>>> C.D.meth.__qualname__
'C.D.meth'

모듈을 가리키는데 사용될 때, 완전히 정규화된 이름(fully qualified name)은 모든 부모 패키지들을 포함해서 모듈로 가는 점으로 분리된 이름을 의미합니다, 예를 들어, email.mime.text:

>>> import email.mime.text
>>> email.mime.text.__name__
'email.mime.text'

reference count (참조 횟수)

The number of references to an object. When the reference count of an object drops to zero, it is deallocated. Some objects are immortal and have reference counts that are never modified, and therefore the objects are never deallocated. Reference counting is generally not visible to Python code, but it is a key element of the CPython implementation. Programmers can call the sys.getrefcount() function to return the reference count for a particular object.

regular package (정규 패키지)

__init__.py 파일을 포함하는 디렉터리와 같은 전통적인 패키지.

이름 공간 패키지 도 보세요.

REPL

An acronym for the “read–eval–print loop”, another name for the interactive interpreter shell.

__slots__

클래스 내부의 선언인데, 인스턴스 어트리뷰트들을 위한 공간을 미리 선언하고 인스턴스 딕셔너리를 제거함으로써 메모리를 절감하는 효과를 줍니다. 인기 있기는 하지만, 이 테크닉은 올바르게 사용하기가 좀 까다로운 편이라서, 메모리에 민감한 응용 프로그램에서 많은 수의 인스턴스가 있는 특별한 경우로 한정하는 것이 좋습니다.

sequence (시퀀스)

An iterable which supports efficient element access using integer indices via the __getitem__() special method and defines a __len__() method that returns the length of the sequence. Some built-in sequence types are list, str, tuple, and bytes. Note that dict also supports __getitem__() and __len__(), but is considered a mapping rather than a sequence because the lookups use arbitrary hashable keys rather than integers.

The collections.abc.Sequence abstract base class defines a much richer interface that goes beyond just __getitem__() and __len__(), adding count(), index(), __contains__(), and __reversed__(). Types that implement this expanded interface can be registered explicitly using register(). For more documentation on sequence methods generally, see Common Sequence Operations.

set comprehension (집합 컴프리헨션)

이터러블에 있는 요소 전체나 일부를 처리하고 결과를 담은 집합을 반환하는 간결한 방법. results = {c for c in 'abracadabra' if c not in 'abc'}는 문자열의 집합 {'r', 'd'}를 생성합니다. 리스트, 집합, 딕셔너리의 디스플레이(display)을 참조하십시오.

single dispatch (싱글 디스패치)

구현이 하나의 인자의 형에 기초해서 결정되는 제네릭 함수 디스패치의 한 형태.

slice (슬라이스)

보통 시퀀스 의 일부를 포함하는 객체. 슬라이스는 서브 스크립트 표기법을 사용해서 만듭니다. variable_name[1:3:5] 처럼, [] 안에서 여러 개의 숫자를 콜론으로 분리합니다. 대괄호 (서브 스크립트) 표기법은 내부적으로 slice 객체를 사용합니다.

soft deprecated

A soft deprecated API should not be used in new code, but it is safe for already existing code to use it. The API remains documented and tested, but will not be enhanced further.

Soft deprecation, unlike normal deprecation, does not plan on removing the API and will not emit warnings.

See PEP 387: Soft Deprecation [https://peps.python.org/pep-0387/#soft-deprecation].

special method (특수 메서드)

파이썬이 형에 어떤 연산을, 덧셈 같은, 실행할 때 묵시적으로 호출되는 메서드. 이런 메서드는 두 개의 밑줄로 시작하고 끝나는 이름을 갖고 있습니다. 특수 메서드는 특수 메서드 이름들 에 문서로 만들어져 있습니다.

statement (문장)

문장은 스위트 (코드의 “블록(block)”) 를 구성하는 부분입니다. 문장은 표현식 이거나 키워드를 사용하는 여러 가지 구조물 중의 하나입니다. 가령 if, while, for.

static type checker

An external tool that reads Python code and analyzes it, looking for issues such as incorrect types. See also type hints and the typing module.

strong reference

In Python’s C API, a strong reference is a reference to an object which is owned by the code holding the reference. The strong reference is taken by calling Py_INCREF() when the reference is created and released with Py_DECREF() when the reference is deleted.

The Py_NewRef() function can be used to create a strong reference to an object. Usually, the Py_DECREF() function must be called on the strong reference before exiting the scope of the strong reference, to avoid leaking one reference.

See also borrowed reference.

text encoding (텍스트 인코딩)

A string in Python is a sequence of Unicode code points (in range U+0000–U+10FFFF). To store or transfer a string, it needs to be serialized as a sequence of bytes.

Serializing a string into a sequence of bytes is known as “encoding”, and recreating the string from the sequence of bytes is known as “decoding”.

There are a variety of different text serialization codecs, which are collectively referred to as “text encodings”.

text file (텍스트 파일)

str 객체를 읽고 쓸 수 있는 파일 객체. 종종, 텍스트 파일은 실제로는 바이트 지향 데이터스트림을 액세스하고 텍스트 인코딩 을 자동 처리합니다. 텍스트 파일의 예로는 텍스트 모드 ('r' 또는 'w') 로 열린 파일, sys.stdin, sys.stdout, io.StringIO 의 인스턴스를 들 수 있습니다.

바이트열류 객체 를 읽고 쓸 수 있는 파일 객체에 대해서는 바이너리 파일 도 참조하세요.

triple-quoted string (삼중 따옴표 된 문자열)

따옴표 (”) 나 작은따옴표 (’) 세 개로 둘러싸인 문자열. 그냥 따옴표 하나로 둘러싸인 문자열에 없는 기능을 제공하지는 않지만, 여러 가지 이유에서 쓸모가 있습니다. 이스케이프 되지 않은 작은따옴표나 큰따옴표를 문자열 안에 포함할 수 있도록 하고, 연결 문자를 쓰지 않고도 여러 줄에 걸칠 수 있는데, 독스트링을 쓸 때 특히 쓸모 있습니다.

type (형)

The type of a Python object determines what kind of object it is; every object has a type. An object’s type is accessible as its __class__ attribute or can be retrieved with type(obj).

type alias (형 에일리어스)

형을 식별자에 대입하여 만들어지는 형의 동의어.

형 에일리어스는 형 힌트를 단순화하는 데 유용합니다. 예를 들면:

def remove_gray_shades(
        colors: list[tuple[int, int, int]]) -> list[tuple[int, int, int]]:
    pass

는 다음과 같이 더 읽기 쉽게 만들 수 있습니다:

Color = tuple[int, int, int]

def remove_gray_shades(colors: list[Color]) -> list[Color]:
    pass

이 기능을 설명하는 typing과 PEP 484 [https://peps.python.org/pep-0484/]를 참조하세요.

type hint (형 힌트)

변수, 클래스 어트리뷰트 및 함수 매개변수 나 반환 값의 기대되는 형을 지정하는 어노테이션.

Type hints are optional and are not enforced by Python but they are useful to static type checkers. They can also aid IDEs with code completion and refactoring.

지역 변수를 제외하고, 전역 변수, 클래스 어트리뷰트 및 함수의 형 힌트는 typing.get_type_hints()를 사용하여 액세스할 수 있습니다.

이 기능을 설명하는 typing과 PEP 484 [https://peps.python.org/pep-0484/]를 참조하세요.

universal newlines (유니버설 줄 넘김)

다음과 같은 것들을 모두 줄의 끝으로 인식하는, 텍스트 스트림을 해석하는 태도: 유닉스 개행 문자 관례 '\n', 윈도우즈 관례 '\r\n', 예전의 매킨토시 관례 '\r'. 추가적인 사용에 관해서는 bytes.splitlines() 뿐만 아니라 PEP 278 [https://peps.python.org/pep-0278/] 와 PEP 3116 [https://peps.python.org/pep-3116/] 도 보세요.

variable annotation (변수 어노테이션)

변수 또는 클래스 어트리뷰트의 어노테이션.

변수 또는 클래스 어트리뷰트에 어노테이션을 달 때 대입은 선택 사항입니다:

class C:
    field: 'annotation'

변수 어노테이션은 일반적으로 형 힌트로 사용됩니다: 예를 들어, 이 변수는 int 값을 가질 것으로 기대됩니다:

count: int = 0

변수 어노테이션 문법은 섹션 어노테이트된 대입문(Annotated assignment statements) 에서 설명합니다.

See function annotation, PEP 484 [https://peps.python.org/pep-0484/] and PEP 526 [https://peps.python.org/pep-0526/], which describe this functionality. Also see Annotations Best Practices for best practices on working with annotations.

virtual environment (가상 환경)

파이썬 사용자와 응용 프로그램이, 같은 시스템에서 실행되는 다른 파이썬 응용 프로그램들의 동작에 영향을 주지 않으면서, 파이썬 배포 패키지들을 설치하거나 업그레이드하는 것을 가능하게 하는, 협력적으로 격리된 실행 환경.

venv 도 보세요.

virtual machine (가상 기계)

소프트웨어만으로 정의된 컴퓨터. 파이썬의 가상 기계는 바이트 코드 컴파일러가 출력하는 바이트 코드를 실행합니다.

Zen of Python (파이썬 젠)

파이썬 디자인 원리와 철학들의 목록인데, 언어를 이해하고 사용하는 데 도움이 됩니다. 이 목록은 대화형 프롬프트에서 “import this” 를 입력하면 보입니다.

이 설명서에 관하여

이 설명서는 reStructuredText [https://docutils.sourceforge.io/rst.html] 소스에서 만들어진 것으로, 파이썬 설명서를 위해 특별히 제작된 문서 처리기인 Sphinx [https://www.sphinx-doc.org/] 를 사용했습니다.

설명서와 이를 위한 툴체인 개발은 파이썬 자체와 마찬가지로 전적으로 자원봉사자의 노력입니다. 기여하고 싶다면, 참여 방법에 대한 정보는 버그 다루기 페이지를 참고하십시오. 새로운 자원봉사자는 언제나 환영합니다!

다음 분들에게 많은 감사를 드립니다:

Fred L. Drake, Jr., 원래 파이썬 설명서 도구 집합의 작성자이자 많은 콘텐츠의 작가;

the Docutils [https://docutils.sourceforge.io/] project for creating reStructuredText and the Docutils suite;

Fredrik Lundh for his Alternative Python Reference project from which Sphinx got many good ideas.

파이썬 설명서의 공헌자들

많은 사람이 파이썬 언어, 파이썬 표준 라이브러리 및 파이썬 설명서에 기여했습니다. 기여자의 부분적인 목록은 파이썬 소스 배포판의 Misc/ACKS [https://github.com/python/cpython/tree/main/Misc/ACKS] 를 참조하십시오.

파이썬이 이런 멋진 설명서를 갖게 된 것은 파이썬 커뮤니티의 입력과 기여 때문입니다 – 감사합니다!

버그 다루기

파이썬은 안정성에 대해 명성을 쌓아온 성숙한 프로그래밍 언어입니다. 이 평판을 유지하기 위해, 개발자는 파이썬에서 여러분이 발견한 결함을 알고 싶어 합니다.

때로는 버그를 직접 수정하고 패치를 파이썬에 제공하는 것이 프로세스를 간소화하고 인력을 덜 요구하기 때문에 더 빠를 수 있습니다. 이바지하는 방법을 배우세요.

설명서 버그

If you find a bug in this documentation or would like to propose an improvement, please submit a bug report on the issue tracker. If you have a suggestion on how to fix it, include that as well.

You can also open a discussion item on our Documentation Discourse forum [https://discuss.python.org/c/documentation/26].

If you find a bug in the theme (HTML / CSS / JavaScript) of the documentation, please submit a bug report on the python-doc-theme issue tracker [https://github.com/python/python-docs-theme].

더 보기

설명서 버그 [https://github.com/python/cpython/issues?q=is%3Aissue+is%3Aopen+label%3Adocs]

파이썬 문제 추적기에 제출된 설명서 버그 목록.

이슈 추적 [https://devguide.python.org/tracker/]

추적기에 개선을 보고하는 것과 관련된 절차 개요.

설명서에 도움 주기 [https://devguide.python.org/docquality/#helping-with-documentation]

파이썬 설명서에 기여하는 데 관심이 있는 개인을 위한 종합 지침서.

Documentation Translations [https://devguide.python.org/documentation/translating/]

A list of GitHub pages for documentation translation and their primary contacts.

파이썬 문제 추적기 사용하기

Issue reports for Python itself should be submitted via the GitHub issues tracker (https://github.com/python/cpython/issues). The GitHub issues tracker offers a web form which allows pertinent information to be entered and submitted to the developers.

The first step in filing a report is to determine whether the problem has already been reported. The advantage in doing so, aside from saving the developers’ time, is that you learn what has been done to fix it; it may be that the problem has already been fixed for the next release, or additional information is needed (in which case you are welcome to provide it if you can!). To do this, search the tracker using the search box at the top of the page.

If the problem you’re reporting is not already in the list, log in to GitHub. If you don’t already have a GitHub account, create a new account using the “Sign up” link. It is not possible to submit a bug report anonymously.

Being now logged in, you can submit an issue. Click on the “New issue” button in the top bar to report a new issue.

The submission form has two fields, “Title” and “Comment”.

For the “Title” field, enter a very short description of the problem; fewer than ten words is good.

“Comment” 입력란에, 문제를 자세히 설명하는데, 기대한 것과 실제로 일어난 것을 포함합니다. 확장 모듈이 개입하고 있는지, 그리고 사용 중인 하드웨어 및 소프트웨어 플랫폼 (적절한 버전 정보 포함)을 포함해야 합니다.

Each issue report will be reviewed by a developer who will determine what needs to be done to correct the problem. You will receive an update each time an action is taken on the issue.

더 보기

버그를 효과적으로 보고하는 방법 [https://www.chiark.greenend.org.uk/~sgtatham/bugs.html]

유용한 버그 보고서를 작성하는 방법에 대해 자세히 설명하는 기사. 이것은 어떤 종류의 정보가 유용하고 왜 유용한지를 설명합니다.

Bug Writing Guidelines [https://bugzilla.mozilla.org/page.cgi?id=bug-writing.html]

좋은 버그 리포트 작성에 관한 정보. 이 중 일부는 모질라(Mozilla) 프로젝트에만 적용되지만, 일반적인 우수 사례를 설명합니다.

파이썬에 직접 이바지하기 입문

발견한 버그를 보고하는 것 외에도, 패치를 제출하여 문제를 해결할 수 있습니다. 파이썬을 패치하는 방법에 대한 더 많은 정보는 Python Developer’s Guide [https://devguide.python.org/] 에서 찾을 수 있습니다. 질문이 있으면, core-mentorship mailing list [https://mail.python.org/mailman3/lists/core-mentorship.python.org/] 는 파이썬에서 문제를 수정하는 과정에 관한 모든 질문에 대한 답변을 얻을 수 있는 친근한 곳입니다.

저작권

파이썬과 이 설명서는:

Copyright © 2001 Python Software Foundation. All rights reserved.

Copyright © 2000 BeOpen.com. All rights reserved.

Copyright © 1995-2000 Corporation for National Research Initiatives. All rights reserved.

Copyright © 1991-1995 Stichting Mathematisch Centrum. All rights reserved.

전체 라이센스 및 사용 권한 정보는 역사와 라이센스 에서 제공합니다.

역사와 라이센스

소프트웨어의 역사

파이썬은 ABC라는 언어의 후계자로서 네덜란드의 Stichting Mathematisch Centrum (CWI, https://www.cwi.nl/ 참조)의 Guido van Rossum에 의해 1990년대 초반에 만들어졌습니다. 파이썬에는 다른 사람들의 많은 공헌이 포함되었지만, Guido는 파이썬의 주요 저자로 남아 있습니다.

1995년, Guido는 Virginia의 Reston에 있는 Corporation for National Research Initiatives(CNRI, https://www.cnri.reston.va.us/ 참조)에서 파이썬 작업을 계속했고, 이곳에서 여러 버전의 소프트웨어를 출시했습니다.

2000년 5월, Guido와 파이썬 핵심 개발팀은 BeOpen.com으로 옮겨서 BeOpen PythonLabs 팀을 구성했습니다. 같은 해 10월, PythonLabs 팀은 Digital Creations(현재 Zope Corporation; https://www.zope.org/ 참조)로 옮겼습니다. 2001 년, 파이썬 소프트웨어 재단(PSF, https://www.python.org/psf/ 참조)이 설립되었습니다. 이 단체는 파이썬 관련 지적 재산권을 소유하도록 특별히 설립된 비영리 조직입니다. Zope Corporation은 PSF의 후원 회원입니다.

모든 파이썬 배포판은 공개 소스입니다 (공개 소스 정의에 대해서는 https://opensource.org/를 참조하십시오). 역사적으로, 대부분 (하지만 전부는 아닙니다) 파이썬 배포판은 GPL과 호환됩니다; 아래의 표는 다양한 배포판을 요약한 것입니다.

배포판

파생된 곳

해

소유자

GPL 호환?

0.9.0 ~ 1.2

n/a

1991-1995

CWI

yes

1.3 ~ 1.5.2

1.2

1995-1999

CNRI

yes

1.6

1.5.2

2000

CNRI

no

2.0

1.6

2000

BeOpen.com

no

1.6.1

1.6

2001

CNRI

no

2.1

2.0+1.6.1

2001

PSF

no

2.0.1

2.0+1.6.1

2001

PSF

yes

2.1.1

2.1+2.0.1

2001

PSF

yes

2.1.2

2.1.1

2002

PSF

yes

2.1.3

2.1.2

2002

PSF

yes

2.2 이상

2.1.1

2001-현재

PSF

yes

참고

GPL과 호환된다는 것은 우리가 GPL로 파이썬을 배포한다는 것을 의미하지는 않습니다. 모든 파이썬 라이센스는 GPL과 달리 여러분의 변경을 공개 소스로 만들지 않고 수정된 버전을 배포할 수 있게 합니다. GPL 호환 라이센스는 파이썬과 GPL 하에 발표된 다른 소프트웨어를 결합할 수 있게 합니다; 다른 것들은 그렇지 않습니다.

Guido의 지도하에 이 배포를 가능하게 만든 많은 외부 자원봉사자들에게 감사드립니다.

파이썬에 액세스하거나 사용하기 위한 이용 약관

파이썬 소프트웨어와 설명서는 PSF License Agreement에 따라 라이센스가 부여됩니다.

파이썬 3.8.6부터, 설명서의 예제, 조리법 및 기타 코드는 PSF License Agreement와 Zero-Clause BSD license에 따라 이중 라이센스가 부여됩니다.

파이썬에 통합된 일부 소프트웨어에는 다른 라이센스가 적용됩니다. 라이센스는 해당 라이센스에 해당하는 코드와 함께 나열됩니다. 이러한 라이센스의 불완전한 목록은 포함된 소프트웨어에 대한 라이센스 및 승인를 참조하십시오.

PSF LICENSE AGREEMENT FOR PYTHON 3.14.0a2

1. This LICENSE AGREEMENT is between the Python Software Foundation ("PSF"), and
   the Individual or Organization ("Licensee") accessing and otherwise using Python
   3.14.0a2 software in source or binary form and its associated documentation.

2. Subject to the terms and conditions of this License Agreement, PSF hereby
   grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
   analyze, test, perform and/or display publicly, prepare derivative works,
   distribute, and otherwise use Python 3.14.0a2 alone or in any derivative
   version, provided, however, that PSF's License Agreement and PSF's notice of
   copyright, i.e., "Copyright © 2001 Python Software Foundation; All Rights
   Reserved" are retained in Python 3.14.0a2 alone or in any derivative version
   prepared by Licensee.

3. In the event Licensee prepares a derivative work that is based on or
   incorporates Python 3.14.0a2 or any part thereof, and wants to make the
   derivative work available to others as provided herein, then Licensee hereby
   agrees to include in any such work a brief summary of the changes made to Python
   3.14.0a2.

4. PSF is making Python 3.14.0a2 available to Licensee on an "AS IS" basis.
   PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF
   EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY REPRESENTATION OR
   WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE
   USE OF PYTHON 3.14.0a2 WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON 3.14.0a2
   FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
   MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 3.14.0a2, OR ANY DERIVATIVE
   THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

6. This License Agreement will automatically terminate upon a material breach of
   its terms and conditions.

7. Nothing in this License Agreement shall be deemed to create any relationship
   of agency, partnership, or joint venture between PSF and Licensee.  This License
   Agreement does not grant permission to use PSF trademarks or trade name in a
   trademark sense to endorse or promote products or services of Licensee, or any
   third party.

8. By copying, installing or otherwise using Python 3.14.0a2, Licensee agrees
   to be bound by the terms and conditions of this License Agreement.

BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0

BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1

1. This LICENSE AGREEMENT is between BeOpen.com ("BeOpen"), having an office at
   160 Saratoga Avenue, Santa Clara, CA 95051, and the Individual or Organization
   ("Licensee") accessing and otherwise using this software in source or binary
   form and its associated documentation ("the Software").

2. Subject to the terms and conditions of this BeOpen Python License Agreement,
   BeOpen hereby grants Licensee a non-exclusive, royalty-free, world-wide license
   to reproduce, analyze, test, perform and/or display publicly, prepare derivative
   works, distribute, and otherwise use the Software alone or in any derivative
   version, provided, however, that the BeOpen Python License is retained in the
   Software, alone or in any derivative version prepared by Licensee.

3. BeOpen is making the Software available to Licensee on an "AS IS" basis.
   BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF
   EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND DISCLAIMS ANY REPRESENTATION OR
   WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE
   USE OF THE SOFTWARE WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE SOFTWARE FOR
   ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF USING,
   MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY DERIVATIVE THEREOF, EVEN IF
   ADVISED OF THE POSSIBILITY THEREOF.

5. This License Agreement will automatically terminate upon a material breach of
   its terms and conditions.

6. This License Agreement shall be governed by and interpreted in all respects
   by the law of the State of California, excluding conflict of law provisions.
   Nothing in this License Agreement shall be deemed to create any relationship of
   agency, partnership, or joint venture between BeOpen and Licensee.  This License
   Agreement does not grant permission to use BeOpen trademarks or trade names in a
   trademark sense to endorse or promote products or services of Licensee, or any
   third party.  As an exception, the "BeOpen Python" logos available at
   http://www.pythonlabs.com/logos.html may be used according to the permissions
   granted on that web page.

7. By copying, installing or otherwise using the software, Licensee agrees to be
   bound by the terms and conditions of this License Agreement.

CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1

1. This LICENSE AGREEMENT is between the Corporation for National Research
   Initiatives, having an office at 1895 Preston White Drive, Reston, VA 20191
   ("CNRI"), and the Individual or Organization ("Licensee") accessing and
   otherwise using Python 1.6.1 software in source or binary form and its
   associated documentation.

2. Subject to the terms and conditions of this License Agreement, CNRI hereby
   grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
   analyze, test, perform and/or display publicly, prepare derivative works,
   distribute, and otherwise use Python 1.6.1 alone or in any derivative version,
   provided, however, that CNRI's License Agreement and CNRI's notice of copyright,
   i.e., "Copyright © 1995-2001 Corporation for National Research Initiatives; All
   Rights Reserved" are retained in Python 1.6.1 alone or in any derivative version
   prepared by Licensee.  Alternately, in lieu of CNRI's License Agreement,
   Licensee may substitute the following text (omitting the quotes): "Python 1.6.1
   is made available subject to the terms and conditions in CNRI's License
   Agreement.  This Agreement together with Python 1.6.1 may be located on the
   internet using the following unique, persistent identifier (known as a handle):
   1895.22/1013.  This Agreement may also be obtained from a proxy server on the
   internet using the following URL: http://hdl.handle.net/1895.22/1013."

3. In the event Licensee prepares a derivative work that is based on or
   incorporates Python 1.6.1 or any part thereof, and wants to make the derivative
   work available to others as provided herein, then Licensee hereby agrees to
   include in any such work a brief summary of the changes made to Python 1.6.1.

4. CNRI is making Python 1.6.1 available to Licensee on an "AS IS" basis.  CNRI
   MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF EXAMPLE,
   BUT NOT LIMITATION, CNRI MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY
   OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF
   PYTHON 1.6.1 WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON 1.6.1 FOR
   ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
   MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1, OR ANY DERIVATIVE
   THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

6. This License Agreement will automatically terminate upon a material breach of
   its terms and conditions.

7. This License Agreement shall be governed by the federal intellectual property
   law of the United States, including without limitation the federal copyright
   law, and, to the extent such U.S. federal law does not apply, by the law of the
   Commonwealth of Virginia, excluding Virginia's conflict of law provisions.
   Notwithstanding the foregoing, with regard to derivative works based on Python
   1.6.1 that incorporate non-separable material that was previously distributed
   under the GNU General Public License (GPL), the law of the Commonwealth of
   Virginia shall govern this License Agreement only as to issues arising under or
   with respect to Paragraphs 4, 5, and 7 of this License Agreement.  Nothing in
   this License Agreement shall be deemed to create any relationship of agency,
   partnership, or joint venture between CNRI and Licensee.  This License Agreement
   does not grant permission to use CNRI trademarks or trade name in a trademark
   sense to endorse or promote products or services of Licensee, or any third
   party.

8. By clicking on the "ACCEPT" button where indicated, or by copying, installing
   or otherwise using Python 1.6.1, Licensee agrees to be bound by the terms and
   conditions of this License Agreement.

CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2

Copyright © 1991 - 1995, Stichting Mathematisch Centrum Amsterdam, The
Netherlands.  All rights reserved.

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided that
the above copyright notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting documentation, and that
the name of Stichting Mathematisch Centrum or CWI not be used in advertising or
publicity pertaining to distribution of the software without specific, written
prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE FOR ANY SPECIAL, INDIRECT
OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON 3.14.0a2 DOCUMENTATION

Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

포함된 소프트웨어에 대한 라이센스 및 승인

이 섹션은 파이썬 배포판에 포함된 제삼자 소프트웨어에 대한 불완전하지만 늘어나고 있는 라이센스와 승인의 목록입니다.

메르센 트위스터

The _random C extension underlying the random module includes code based on a download from http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html. The following are the verbatim comments from the original code:

A C-program for MT19937, with initialization improved 2002/1/26.
Coded by Takuji Nishimura and Makoto Matsumoto.

Before using, initialize the state by using init_genrand(seed)
or init_by_array(init_key, key_length).

Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.

 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.

 3. The names of its contributors may not be used to endorse or promote
    products derived from this software without specific prior written
    permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Any feedback is very welcome.
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)

소켓

The socket module uses the functions, getaddrinfo(), and getnameinfo(), which are coded in separate source files from the WIDE Project, https://www.wide.ad.jp/.

Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of the project nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

비동기 소켓 서비스

The test.support.asynchat and test.support.asyncore modules contain the following notice:

Copyright 1996 by Sam Rushing

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that copyright notice and this permission
notice appear in supporting documentation, and that the name of Sam
Rushing not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

쿠키 관리

http.cookies 모듈은 다음과 같은 주의 사항을 포함합니다:

Copyright 2000 by Timothy O'Malley <timo@alum.mit.edu>

               All Rights Reserved

Permission to use, copy, modify, and distribute this software
and its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that copyright notice and this permission
notice appear in supporting documentation, and that the name of
Timothy O'Malley  not be used in advertising or publicity
pertaining to distribution of the software without specific, written
prior permission.

Timothy O'Malley DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS, IN NO EVENT SHALL Timothy O'Malley BE LIABLE FOR
ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

실행 추적

trace 모듈은 다음과 같은 주의 사항을 포함합니다:

portions copyright 2001, Autonomous Zones Industries, Inc., all rights...
err...  reserved and offered to the public under the terms of the
Python 2.2 license.
Author: Zooko O'Whielacronx
http://zooko.com/
mailto:zooko@zooko.com

Copyright 2000, Mojam Media, Inc., all rights reserved.
Author: Skip Montanaro

Copyright 1999, Bioreason, Inc., all rights reserved.
Author: Andrew Dalke

Copyright 1995-1997, Automatrix, Inc., all rights reserved.
Author: Skip Montanaro

Copyright 1991-1995, Stichting Mathematisch Centrum, all rights reserved.

Permission to use, copy, modify, and distribute this Python software and
its associated documentation for any purpose without fee is hereby
granted, provided that the above copyright notice appears in all copies,
and that both that copyright notice and this permission notice appear in
supporting documentation, and that the name of neither Automatrix,
Bioreason or Mojam Media be used in advertising or publicity pertaining to
distribution of the software without specific, written prior permission.

UUencode 및 UUdecode 함수

The uu codec contains the following notice:

Copyright 1994 by Lance Ellinghouse
Cathedral City, California Republic, United States of America.
                       All Rights Reserved
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Lance Ellinghouse
not be used in advertising or publicity pertaining to distribution
of the software without specific, written prior permission.
LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE CENTRUM BE LIABLE
FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Modified by Jack Jansen, CWI, July 1995:
- Use binascii module to do the actual line-by-line conversion
  between ascii and binary. This results in a 1000-fold speedup. The C
  version is still 5 times faster, though.
- Arguments more compliant with Python standard

XML 원격 프로시저 호출

xmlrpc.client 모듈은 다음과 같은 주의 사항을 포함합니다:

    The XML-RPC client interface is

Copyright (c) 1999-2002 by Secret Labs AB
Copyright (c) 1999-2002 by Fredrik Lundh

By obtaining, using, and/or copying this software and/or its
associated documentation, you agree that you have read, understood,
and will comply with the following terms and conditions:

Permission to use, copy, modify, and distribute this software and
its associated documentation for any purpose and without fee is
hereby granted, provided that the above copyright notice appears in
all copies, and that both that copyright notice and this permission
notice appear in supporting documentation, and that the name of
Secret Labs AB or the author not be used in advertising or publicity
pertaining to distribution of the software without specific, written
prior permission.

SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
ABILITY AND FITNESS.  IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
OF THIS SOFTWARE.

test_epoll

The test.test_epoll module contains the following notice:

Copyright (c) 2001-2006 Twisted Matrix Laboratories.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Select kqueue

select 모듈은 kqueue 인터페이스에 대해 다음과 같은 주의 사항을 포함합니다:

Copyright (c) 2000 Doug White, 2006 James Knight, 2007 Christian Heimes
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

SipHash24

파일 Python/pyhash.c 에는 Dan Bernstein의 SipHash24 알고리즘의 Marek Majkowski의 구현이 포함되어 있습니다. 여기에는 다음과 같은 내용이 포함되어 있습니다:

<MIT License>
Copyright (c) 2013  Marek Majkowski <marek@popcount.org>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
</MIT License>

Original location:
   https://github.com/majek/csiphash/

Solution inspired by code from:
   Samuel Neves (supercop/crypto_auth/siphash24/little)
   djb (supercop/crypto_auth/siphash24/little2)
   Jean-Philippe Aumasson (https://131002.net/siphash/siphash24.c)

strtod 와 dtoa

The file Python/dtoa.c, which supplies C functions dtoa and strtod for conversion of C doubles to and from strings, is derived from the file of the same name by David M. Gay, currently available from https://web.archive.org/web/20220517033456/http://www.netlib.org/fp/dtoa.c. The original file, as retrieved on March 16, 2009, contains the following copyright and licensing notice:

/****************************************************************
 *
 * The author of this software is David M. Gay.
 *
 * Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 *
 ***************************************************************/

OpenSSL

The modules hashlib, posix and ssl use the OpenSSL library for added performance if made available by the operating system. Additionally, the Windows and macOS installers for Python may include a copy of the OpenSSL libraries, so we include a copy of the OpenSSL license here. For the OpenSSL 3.0 release, and later releases derived from that, the Apache License v2 applies:

                              Apache License
                        Version 2.0, January 2004
                     https://www.apache.org/licenses/

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END OF TERMS AND CONDITIONS

expat

The pyexpat extension is built using an included copy of the expat sources unless the build is configured --with-system-expat:

Copyright (c) 1998, 1999, 2000 Thai Open Source Software Center Ltd
                               and Clark Cooper

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

libffi

The _ctypes C extension underlying the ctypes module is built using an included copy of the libffi sources unless the build is configured --with-system-libffi:

Copyright (c) 1996-2008  Red Hat, Inc and others.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
``Software''), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.

zlib

zlib 확장은 시스템에서 발견된 zlib 버전이 너무 오래되어서 빌드에 사용될 수 없으면, 포함된 zlib 소스 사본을 사용하여 빌드됩니다:

Copyright (C) 1995-2011 Jean-loup Gailly and Mark Adler

This software is provided 'as-is', without any express or implied
warranty.  In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.

Jean-loup Gailly        Mark Adler
jloup@gzip.org          madler@alumni.caltech.edu

cfuhash

tracemalloc 에 의해 사용되는 해시 테이블의 구현은 cfuhash 프로젝트를 기반으로 합니다:

Copyright (c) 2005 Don Owens
All rights reserved.

This code is released under the BSD license:

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

  * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.

  * Redistributions in binary form must reproduce the above
    copyright notice, this list of conditions and the following
    disclaimer in the documentation and/or other materials provided
    with the distribution.

  * Neither the name of the author nor the names of its
    contributors may be used to endorse or promote products derived
    from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
OF THE POSSIBILITY OF SUCH DAMAGE.

libmpdec

The _decimal C extension underlying the decimal module is built using an included copy of the libmpdec library unless the build is configured --with-system-libmpdec:

Copyright (c) 2008-2020 Stefan Krah. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

W3C C14N 테스트 스위트

The C14N 2.0 test suite in the test package (Lib/test/xmltestdata/c14n-20/) was retrieved from the W3C website at https://www.w3.org/TR/xml-c14n2-testcases/ and is distributed under the 3-clause BSD license:

Copyright (c) 2013 W3C(R) (MIT, ERCIM, Keio, Beihang),
All Rights Reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

* Redistributions of works must retain the original copyright notice,
  this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the original copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.
* Neither the name of the W3C nor the names of its contributors may be
  used to endorse or promote products derived from this work without
  specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

mimalloc

MIT License:

Copyright (c) 2018-2021 Microsoft Corporation, Daan Leijen

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

asyncio

Parts of the asyncio module are incorporated from uvloop 0.16 [https://github.com/MagicStack/uvloop/tree/v0.16.0], which is distributed under the MIT license:

Copyright (c) 2015-2021 MagicStack Inc.  http://magic.io

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Global Unbounded Sequences (GUS)

The file Python/qsbr.c is adapted from FreeBSD’s “Global Unbounded Sequences” safe memory reclamation scheme in subr_smr.c [https://github.com/freebsd/freebsd-src/blob/main/sys/kern/subr_smr.c]. The file is distributed under the 2-Clause BSD License:

Copyright (c) 2019,2020 Jeffrey Roberson <jeff@FreeBSD.org>

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice unmodified, this list of conditions, and the following
   disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Python 모듈 목록

_ | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | z

| _ |
| __future__ | Future statement definitions
| __main__ | The environment where top-level code is run. Covers command-line interfaces, import-time behavior, and ``__name__ == '__main__'``.
| _thread | Low-level threading API.
| _tkinter | A binary module that contains the low-level interface to Tcl/Tk.
| a |
| abc | Abstract base classes according to :pep:`3119`.
| aifc | 폐지됨: Removed in 3.13.
| annotationlib | Functionality for introspecting annotations
| argparse | Command-line option and argument parsing library.
| array | Space efficient arrays of uniformly typed numeric values.
| ast | Abstract Syntax Tree classes and manipulation.
| asynchat | 폐지됨: Removed in 3.12.
| asyncio | Asynchronous I/O.
| asyncore | 폐지됨: Removed in 3.12.
| atexit | Register and execute cleanup functions.
| audioop | 폐지됨: Removed in 3.13.
| b |
| base64 | RFC 4648: Base16, Base32, Base64 Data Encodings; Base85 and Ascii85
| bdb | Debugger framework.
| binascii | Tools for converting between binary and various ASCII-encoded binary representations.
| bisect | Array bisection algorithms for binary searching.
| builtins | The module that provides the built-in namespace.
| bz2 | Interfaces for bzip2 compression and decompression.
| c |
| calendar | Functions for working with calendars, including some emulation of the Unix cal program.
| cgi | 폐지됨: Removed in 3.13.
| cgitb | 폐지됨: Removed in 3.13.
| chunk | 폐지됨: Removed in 3.13.
| cmath | Mathematical functions for complex numbers.
| cmd | Build line-oriented command interpreters.
| code | Facilities to implement read-eval-print loops.
| codecs | Encode and decode data and streams.
| codeop | Compile (possibly incomplete) Python code.
- | collections | Container datatypes
|     collections.abc | Abstract base classes for containers
| colorsys | Conversion functions between RGB and other color systems.
| compileall | Tools for byte-compiling all Python source files in a directory tree.
- | concurrent |
|     concurrent.futures | Execute computations concurrently using threads or processes.
| configparser | Configuration file parser.
| contextlib | Utilities for with-statement contexts.
| contextvars | Context Variables
| copy | Shallow and deep copy operations.
| copyreg | Register pickle support functions.
| cProfile |
| crypt | 폐지됨: Removed in 3.13.
| csv | Write and read tabular data to and from delimited files.
| ctypes | A foreign function library for Python.
- | curses (Unix) | An interface to the curses library, providing portable terminal handling.
|     curses.ascii | Constants and set-membership functions for ASCII characters.
|     curses.panel | A panel stack extension that adds depth to curses windows.
|     curses.textpad | Emacs-like input editing in a curses window.
| d |
| dataclasses | Generate special methods on user-defined classes.
| datetime | Basic date and time types.
- | dbm | Interfaces to various Unix "database" formats.
|     dbm.dumb | Portable implementation of the simple DBM interface.
|     dbm.gnu (Unix) | GNU database manager
|     dbm.ndbm (Unix) | The New Database Manager
|     dbm.sqlite3 (All) | SQLite backend for dbm
| decimal | Implementation of the General Decimal Arithmetic Specification.
| difflib | Helpers for computing differences between objects.
| dis | Disassembler for Python bytecode.
| distutils | 폐지됨: Removed in 3.12.
| doctest | Test pieces of code within docstrings.
| e |
- | email | Package supporting the parsing, manipulating, and generating email messages.
|     email.charset | Character Sets
|     email.contentmanager | Storing and Retrieving Content from MIME Parts
|     email.encoders | Encoders for email message payloads.
|     email.errors | The exception classes used by the email package.
|     email.generator | Generate flat text email messages from a message structure.
|     email.header | Representing non-ASCII headers
|     email.headerregistry | Automatic Parsing of headers based on the field name
|     email.iterators | Iterate over a message object tree.
|     email.message | The base class representing email messages.
|     email.mime | Build MIME messages.
|     email.mime.application |
|     email.mime.audio |
|     email.mime.base |
|     email.mime.image |
|     email.mime.message |
|     email.mime.multipart |
|     email.mime.nonmultipart |
|     email.mime.text |
|     email.parser | Parse flat text email messages to produce a message object structure.
|     email.policy | Controlling the parsing and generating of messages
|     email.utils | Miscellaneous email package utilities.
- | encodings |
|     encodings.idna | Internationalized Domain Names implementation
|     encodings.mbcs | Windows ANSI codepage
|     encodings.utf_8_sig | UTF-8 codec with BOM signature
| ensurepip | Bootstrapping the "pip" installer into an existing Python installation or virtual environment.
| enum | Implementation of an enumeration class.
| errno | Standard errno system symbols.
| f |
| faulthandler | Dump the Python traceback.
| fcntl (Unix) | The fcntl() and ioctl() system calls.
| filecmp | Compare files efficiently.
| fileinput | Loop over standard input or a list of files.
| fnmatch | Unix shell style filename pattern matching.
| fractions | Rational numbers.
| ftplib | FTP protocol client (requires sockets).
| functools | Higher-order functions and operations on callable objects.
| g |
| gc | Interface to the cycle-detecting garbage collector.
| getopt | Portable parser for command line options; support both short and long option names.
| getpass | Portable reading of passwords and retrieval of the userid.
| gettext | Multilingual internationalization services.
| glob | Unix shell style pathname pattern expansion.
| graphlib | Functionality to operate with graph-like structures
| grp (Unix) | The group database (getgrnam() and friends).
| gzip | Interfaces for gzip compression and decompression using file objects.
| h |
| hashlib | Secure hash and message digest algorithms.
| heapq | Heap queue algorithm (a.k.a. priority queue).
| hmac | Keyed-Hashing for Message Authentication (HMAC) implementation
- | html | Helpers for manipulating HTML.
|     html.entities | Definitions of HTML general entities.
|     html.parser | A simple parser that can handle HTML and XHTML.
- | http | HTTP status codes and messages
|     http.client | HTTP and HTTPS protocol client (requires sockets).
|     http.cookiejar | Classes for automatic handling of HTTP cookies.
|     http.cookies | Support for HTTP state management (cookies).
|     http.server | HTTP server and request handlers.
| i |
| idlelib | Implementation package for the IDLE shell/editor.
| imaplib | IMAP4 protocol client (requires sockets).
| imghdr | 폐지됨: Removed in 3.13.
| imp | 폐지됨: Removed in 3.12.
- | importlib | The implementation of the import machinery.
|     importlib.abc | Abstract base classes related to import
|     importlib.machinery | Importers and path hooks
|     importlib.metadata | Accessing package metadata
|     importlib.resources | Package resource reading, opening, and access
|     importlib.resources.abc | Abstract base classes for resources
|     importlib.util | Utility code for importers
| inspect | Extract information and source code from live objects.
| io | Core tools for working with streams.
| ipaddress | IPv4/IPv6 manipulation library.
| itertools | Functions creating iterators for efficient looping.
| j |
- | json | Encode and decode the JSON format.
|     json.tool | A command-line interface to validate and pretty-print JSON.
| k |
| keyword | Test whether a string is a keyword in Python.
| l |
| linecache | Provides random access to individual lines from text files.
| locale | Internationalization services.
- | logging | Flexible event logging system for applications.
|     logging.config | Configuration of the logging module.
|     logging.handlers | Handlers for the logging module.
| lzma | A Python wrapper for the liblzma compression library.
| m |
| mailbox | Manipulate mailboxes in various formats
| mailcap | 폐지됨: Removed in 3.13.
| marshal | Convert Python objects to streams of bytes and back (with different constraints).
| math | Mathematical functions (sin() etc.).
| mimetypes | Mapping of filename extensions to MIME types.
| mmap | Interface to memory-mapped files for Unix and Windows.
| modulefinder | Find modules used by a script.
| msilib | 폐지됨: Removed in 3.13.
| msvcrt (Windows) | Miscellaneous useful routines from the MS VC++ runtime.
- | multiprocessing | Process-based parallelism.
|     multiprocessing.connection | API for dealing with sockets.
|     multiprocessing.dummy | Dumb wrapper around threading.
|     multiprocessing.managers | Share data between process with shared objects.
|     multiprocessing.pool | Create pools of processes.
|     multiprocessing.shared_memory | Provides shared memory for direct access across processes.
|     multiprocessing.sharedctypes | Allocate ctypes objects from shared memory.
| n |
| netrc | Loading of .netrc files.
| nis | 폐지됨: Removed in 3.13.
| nntplib | 폐지됨: Removed in 3.13.
| numbers | Numeric abstract base classes (Complex, Real, Integral, etc.).
| o |
| operator | Functions corresponding to the standard operators.
| optparse | 폐지됨: Command-line option parsing library.
- | os | Miscellaneous operating system interfaces.
|     os.path | Operations on pathnames.
| ossaudiodev | 폐지됨: Removed in 3.13.
| p |
| pathlib | Object-oriented filesystem paths
| pdb | The Python debugger for interactive interpreters.
| pickle | Convert Python objects to streams of bytes and back.
| pickletools | Contains extensive comments about the pickle protocols and pickle-machine opcodes, as well as some useful functions.
| pipes | 폐지됨: Removed in 3.13.
| pkgutil | Utilities for the import system.
| platform | Retrieves as much platform identifying data as possible.
| plistlib | Generate and parse Apple plist files.
| poplib | POP3 protocol client (requires sockets).
| posix (Unix) | The most common POSIX system calls (normally used via module os).
| pprint | Data pretty printer.
| profile | Python source profiler.
| pstats | Statistics object for use with the profiler.
| pty (Unix) | Pseudo-Terminal Handling for Unix.
| pwd (Unix) | The password database (getpwnam() and friends).
| py_compile | Generate byte-code files from Python source files.
| pyclbr | Supports information extraction for a Python module browser.
| pydoc | Documentation generator and online help system.
| q |
| queue | A synchronized queue class.
| quopri | Encode and decode files using the MIME quoted-printable encoding.
| r |
| random | Generate pseudo-random numbers with various common distributions.
| re | Regular expression operations.
| readline (Unix) | GNU readline support for Python.
| reprlib | Alternate repr() implementation with size limits.
| resource (Unix) | An interface to provide resource usage information on the current process.
| rlcompleter | Python identifier completion, suitable for the GNU readline library.
| runpy | Locate and run Python modules without importing them first.
| s |
| sched | General purpose event scheduler.
| secrets | Generate secure random numbers for managing secrets.
| select | Wait for I/O completion on multiple streams.
| selectors | High-level I/O multiplexing.
| shelve | Python object persistence.
| shlex | Simple lexical analysis for Unix shell-like languages.
| shutil | High-level file operations, including copying.
| signal | Set handlers for asynchronous events.
| site | Module responsible for site-specific configuration.
| sitecustomize |
| smtpd | 폐지됨: Removed in 3.12.
| smtplib | SMTP protocol client (requires sockets).
| sndhdr | 폐지됨: Removed in 3.13.
| socket | Low-level networking interface.
| socketserver | A framework for network servers.
| spwd | 폐지됨: Removed in 3.13.
| sqlite3 | A DB-API 2.0 implementation using SQLite 3.x.
| ssl | TLS/SSL wrapper for socket objects
| stat | Utilities for interpreting the results of os.stat(), os.lstat() and os.fstat().
| statistics | Mathematical statistics functions
| string | Common string operations.
| stringprep | String preparation, as per RFC 3453
| struct | Interpret bytes as packed binary data.
| subprocess | Subprocess management.
| sunau | 폐지됨: Removed in 3.13.
| symtable | Interface to the compiler's internal symbol tables.
- | sys | Access system-specific parameters and functions.
|     sys.monitoring | Access and control event monitoring
| sysconfig | Python's configuration information
| syslog (Unix) | An interface to the Unix syslog library routines.
| t |
| tabnanny | Tool for detecting white space related problems in Python source files in a directory tree.
| tarfile | Read and write tar-format archive files.
| telnetlib | 폐지됨: Removed in 3.13.
| tempfile | Generate temporary files and directories.
| termios (Unix) | POSIX style tty control.
- | test | Regression tests package containing the testing suite for Python.
|     test.regrtest | Drives the regression test suite.
|     test.support | Support for Python's regression test suite.
|     test.support.bytecode_helper | Support tools for testing correct bytecode generation.
|     test.support.import_helper | Support for import tests.
|     test.support.os_helper | Support for os tests.
|     test.support.script_helper | Support for Python's script execution tests.
|     test.support.socket_helper | Support for socket tests.
|     test.support.threading_helper | Support for threading tests.
|     test.support.warnings_helper | Support for warnings tests.
| textwrap | Text wrapping and filling
| threading | Thread-based parallelism.
| time | Time access and conversions.
| timeit | Measure the execution time of small code snippets.
- | tkinter | Interface to Tcl/Tk for graphical user interfaces
|     tkinter.colorchooser (Tk) | Color choosing dialog
|     tkinter.commondialog (Tk) | Tkinter base class for dialogs
|     tkinter.dnd (Tk) | Tkinter drag-and-drop interface
|     tkinter.filedialog (Tk) | Dialog classes for file selection
|     tkinter.font (Tk) | Tkinter font-wrapping class
|     tkinter.messagebox (Tk) | Various types of alert dialogs
|     tkinter.scrolledtext (Tk) | Text widget with a vertical scroll bar.
|     tkinter.simpledialog (Tk) | Simple dialog windows
|     tkinter.ttk | Tk themed widget set
| token | Constants representing terminal nodes of the parse tree.
| tokenize | Lexical scanner for Python source code.
| tomllib | Parse TOML files.
| trace | Trace or track Python statement execution.
| traceback | Print or retrieve a stack traceback.
| tracemalloc | Trace memory allocations.
| tty (Unix) | Utility functions that perform common terminal control operations.
| turtle | An educational framework for simple graphics applications
| turtledemo | A viewer for example turtle scripts
| types | Names for built-in types.
| typing | Support for type hints (see :pep:`484`).
| u |
| unicodedata | Access the Unicode Database.
- | unittest | Unit testing framework for Python.
|     unittest.mock | Mock object library.
- | urllib |
|     urllib.error | Exception classes raised by urllib.request.
|     urllib.parse | Parse URLs into or assemble them from components.
|     urllib.request | Extensible library for opening URLs.
|     urllib.response | Response classes used by urllib.
|     urllib.robotparser | Load a robots.txt file and answer questions about fetchability of other URLs.
| usercustomize |
| uu | 폐지됨: Removed in 3.13.
| uuid | UUID objects (universally unique identifiers) according to RFC 9562
| v |
| venv | Creation of virtual environments.
| w |
| warnings | Issue warning messages and control their disposition.
| wave | Provide an interface to the WAV sound format.
| weakref | Support for weak references and weak dictionaries.
| webbrowser | Easy-to-use controller for web browsers.
| winreg (Windows) | Routines and objects for manipulating the Windows registry.
| winsound (Windows) | Access to the sound-playing machinery for Windows.
- | wsgiref | WSGI Utilities and Reference Implementation.
|     wsgiref.handlers | WSGI server/gateway base classes.
|     wsgiref.headers | WSGI response header tools.
|     wsgiref.simple_server | A simple WSGI HTTP server.
|     wsgiref.types | WSGI types for static type checking
|     wsgiref.util | WSGI environment utilities.
|     wsgiref.validate | WSGI conformance checker.
| x |
| xdrlib | 폐지됨: Removed in 3.13.
- | xml | Package containing XML processing modules
|     xml.dom | Document Object Model API for Python.
|     xml.dom.minidom | Minimal Document Object Model (DOM) implementation.
|     xml.dom.pulldom | Support for building partial DOM trees from SAX events.
|     xml.etree.ElementInclude |
|     xml.etree.ElementTree | Implementation of the ElementTree API.
|     xml.parsers.expat | An interface to the Expat non-validating XML parser.
|     xml.parsers.expat.errors |
|     xml.parsers.expat.model |
|     xml.sax | Package containing SAX2 base classes and convenience functions.
|     xml.sax.handler | Base classes for SAX event handlers.
|     xml.sax.saxutils | Convenience functions and classes for use with SAX.
|     xml.sax.xmlreader | Interface which SAX-compliant XML parsers must implement.
- | xmlrpc |
|     xmlrpc.client | XML-RPC client access.
|     xmlrpc.server | Basic XML-RPC server implementations.
| z |
| zipapp | Manage executable Python zip archives
| zipfile | Read and write ZIP-format archive files.
| zipimport | Support for importing Python modules from ZIP archives.
| zlib | Low-level interface to compression and decompression routines compatible with gzip.
| zoneinfo | IANA time zone support

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Python 3.14.0a2 문서

Welcome! This is the official documentation for Python 3.14.0a2.

Documentation sections:

파이썬 3.14 의 새로운 기능은?
Or all "What's new" documents since Python 2.0

자습서
Start here: a tour of Python's syntax and features

Library reference
Standard library and builtins

Language reference
Syntax and language elements

Python setup and usage
How to install, configure, and use Python

파이썬 HOWTO
In-depth topic manuals

Installing Python modules
Third-party modules and PyPI.org

Distributing Python modules
Publishing modules for use by other people

Extending and embedding
For C/C++ programmers

Python's C API
C API reference

FAQs
Frequently asked questions (with answers!)

Deprecations
Deprecated functionality

Indices, glossary, and search:

Global module index
All modules and libraries

General index
All functions, classes, and terms

용어집
Terms explained

검색 페이지
Search this documentation

Complete table of contents
Lists all sections and subsections

Project information:

Reporting issues

설명서에 기여하기

Download the documentation

History and license of Python

저작권

설명서 정보

Pending removal in Python 3.14

The ma_version_tag field in PyDictObject for extension modules (PEP 699 [https://peps.python.org/pep-0699/]; gh-101193 [https://github.com/python/cpython/issues/101193]).

Creating immutable types with mutable bases (gh-95388 [https://github.com/python/cpython/issues/95388]).

Functions to configure Python’s initialization, deprecated in Python 3.11:

PySys_SetArgvEx(): Set PyConfig.argv instead.

PySys_SetArgv(): Set PyConfig.argv instead.

Py_SetProgramName(): Set PyConfig.program_name instead.

Py_SetPythonHome(): Set PyConfig.home instead.

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Global configuration variables:

Py_DebugFlag: Use PyConfig.parser_debug instead.

Py_VerboseFlag: Use PyConfig.verbose instead.

Py_QuietFlag: Use PyConfig.quiet instead.

Py_InteractiveFlag: Use PyConfig.interactive instead.

Py_InspectFlag: Use PyConfig.inspect instead.

Py_OptimizeFlag: Use PyConfig.optimization_level instead.

Py_NoSiteFlag: Use PyConfig.site_import instead.

Py_BytesWarningFlag: Use PyConfig.bytes_warning instead.

Py_FrozenFlag: Use PyConfig.pathconfig_warnings instead.

Py_IgnoreEnvironmentFlag: Use PyConfig.use_environment instead.

Py_DontWriteBytecodeFlag: Use PyConfig.write_bytecode instead.

Py_NoUserSiteDirectory: Use PyConfig.user_site_directory instead.

Py_UnbufferedStdioFlag: Use PyConfig.buffered_stdio instead.

Py_HashRandomizationFlag: Use PyConfig.use_hash_seed and PyConfig.hash_seed instead.

Py_IsolatedFlag: Use PyConfig.isolated instead.

Py_LegacyWindowsFSEncodingFlag: Use PyPreConfig.legacy_windows_fs_encoding instead.

Py_LegacyWindowsStdioFlag: Use PyConfig.legacy_windows_stdio instead.

Py_FileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_HasFileSystemDefaultEncoding: Use PyConfig.filesystem_encoding instead.

Py_FileSystemDefaultEncodeErrors: Use PyConfig.filesystem_errors instead.

Py_UTF8Mode: Use PyPreConfig.utf8_mode instead. (see Py_PreInitialize())

The Py_InitializeFromConfig() API should be used with PyConfig instead.

Pending removal in Python 3.15

The bundled copy of libmpdecimal.

The PyImport_ImportModuleNoBlock(): Use PyImport_ImportModule() instead.

PyWeakref_GetObject() and PyWeakref_GET_OBJECT(): Use PyWeakref_GetRef() instead.

Py_UNICODE type and the Py_UNICODE_WIDE macro: Use wchar_t instead.

Python initialization functions:

PySys_ResetWarnOptions(): Clear sys.warnoptions and warnings.filters instead.

Py_GetExecPrefix(): Get sys.base_exec_prefix and sys.exec_prefix instead.

Py_GetPath(): Get sys.path instead.

Py_GetPrefix(): Get sys.base_prefix and sys.prefix instead.

Py_GetProgramFullPath(): Get sys.executable instead.

Py_GetProgramName(): Get sys.executable instead.

Py_GetPythonHome(): Get PyConfig.home or the PYTHONHOME environment variable instead.

Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

Py_TPFLAGS_HAVE_FINALIZE: Unneeded since Python 3.8.

PyErr_Fetch(): Use PyErr_GetRaisedException() instead.

PyErr_NormalizeException(): Use PyErr_GetRaisedException() instead.

PyErr_Restore(): Use PyErr_SetRaisedException() instead.

PyModule_GetFilename(): Use PyModule_GetFilenameObject() instead.

PyOS_AfterFork(): Use PyOS_AfterFork_Child() instead.

PySlice_GetIndicesEx(): Use PySlice_Unpack() and PySlice_AdjustIndices() instead.

PyUnicode_AsDecodedObject(): Use PyCodec_Decode() instead.

PyUnicode_AsDecodedUnicode(): Use PyCodec_Decode() instead.

PyUnicode_AsEncodedObject(): Use PyCodec_Encode() instead.

PyUnicode_AsEncodedUnicode(): Use PyCodec_Encode() instead.

PyUnicode_READY(): Unneeded since Python 3.12

PyErr_Display(): Use PyErr_DisplayException() instead.

_PyErr_ChainExceptions(): Use _PyErr_ChainExceptions1() instead.

PyBytesObject.ob_shash member: call PyObject_Hash() instead.

PyDictObject.ma_version_tag member.

Thread Local Storage (TLS) API:

PyThread_create_key(): Use PyThread_tss_alloc() instead.

PyThread_delete_key(): Use PyThread_tss_free() instead.

PyThread_set_key_value(): Use PyThread_tss_set() instead.

PyThread_get_key_value(): Use PyThread_tss_get() instead.

PyThread_delete_key_value(): Use PyThread_tss_delete() instead.

PyThread_ReInitTLS(): Unneeded since Python 3.7.

Pending removal in Python 3.13

Modules (see PEP 594 [https://peps.python.org/pep-0594/]):

aifc

audioop

cgi

cgitb

chunk

crypt

imghdr

mailcap

msilib

nis

nntplib

ossaudiodev

pipes

sndhdr

spwd

sunau

telnetlib

uu

xdrlib

Other modules:

lib2to3, and the 2to3 program (gh-84540 [https://github.com/python/cpython/issues/84540])

APIs:

configparser.LegacyInterpolation (gh-90765 [https://github.com/python/cpython/issues/90765])

locale.resetlocale() (gh-90817 [https://github.com/python/cpython/issues/90817])

turtle.RawTurtle.settiltangle() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.findTestCases() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.getTestCaseNames() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.makeSuite() (gh-50096 [https://github.com/python/cpython/issues/50096])

unittest.TestProgram.usageExit() (gh-67048 [https://github.com/python/cpython/issues/67048])

webbrowser.MacOSX (gh-86421 [https://github.com/python/cpython/issues/86421])

classmethod descriptor chaining (gh-89519 [https://github.com/python/cpython/issues/89519])

importlib.resources deprecated methods:

contents()

is_resource()

open_binary()

open_text()

path()

read_binary()

read_text()

Use importlib.resources.files() instead. Refer to importlib-resources: Migrating from Legacy [https://importlib-resources.readthedocs.io/en/latest/using.html#migrating-from-legacy] (gh-106531 [https://github.com/python/cpython/issues/106531])

Pending removal in Python 3.14

argparse: The type, choices, and metavar parameters of argparse.BooleanOptionalAction are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in gh-92248 [https://github.com/python/cpython/issues/92248].)

ast: The following features have been deprecated in documentation since Python 3.8, now cause a DeprecationWarning to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

ast.Num

ast.Str

ast.Bytes

ast.NameConstant

ast.Ellipsis

Use ast.Constant instead. (Contributed by Serhiy Storchaka in gh-90953 [https://github.com/python/cpython/issues/90953].)

asyncio:

The child watcher classes asyncio.MultiLoopChildWatcher, asyncio.FastChildWatcher, asyncio.AbstractChildWatcher and asyncio.SafeChildWatcher are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

asyncio.set_child_watcher(), asyncio.get_child_watcher(), asyncio.AbstractEventLoopPolicy.set_child_watcher() and asyncio.AbstractEventLoopPolicy.get_child_watcher() are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597 [https://github.com/python/cpython/issues/94597].)

The get_event_loop() method of the default event loop policy now emits a DeprecationWarning if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in gh-100160 [https://github.com/python/cpython/issues/100160].)

collections.abc: Deprecated collections.abc.ByteString. Prefer Sequence or Buffer. For use in typing, prefer a union, like bytes | bytearray, or collections.abc.Buffer. (Contributed by Shantanu Jain in gh-91896 [https://github.com/python/cpython/issues/91896].)

email: Deprecated the isdst parameter in email.utils.localtime(). (Contributed by Alan Williams in gh-72346 [https://github.com/python/cpython/issues/72346].)

importlib.abc deprecated classes:

importlib.abc.ResourceReader

importlib.abc.Traversable

importlib.abc.TraversableResources

Use importlib.resources.abc classes instead:

importlib.resources.abc.Traversable

importlib.resources.abc.TraversableResources

(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963 [https://github.com/python/cpython/issues/93963].)

itertools had undocumented, inefficient, historically buggy, and inconsistent support for copy, deepcopy, and pickle operations. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in gh-101588 [https://github.com/python/cpython/issues/101588].)

multiprocessing: The default start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where 'fork' is currently the default (gh-84559 [https://github.com/python/cpython/issues/84559]). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the get_context() or set_start_method() APIs to explicitly specify when your code requires 'fork'. See 컨텍스트 및 시작 방법.

pathlib: is_relative_to() and relative_to(): passing additional arguments is deprecated.

pkgutil: pkgutil.find_loader() and :func:!pkgutil.get_loader` now raise DeprecationWarning; use importlib.util.find_spec() instead. (Contributed by Nikita Sobolev in gh-97850 [https://github.com/python/cpython/issues/97850].)

pty:

master_open(): use pty.openpty().

slave_open(): use pty.openpty().

sqlite3:

version and version_info.

execute() and executemany() if named placeholders are used and parameters is a sequence instead of a dict.

typing: typing.ByteString, deprecated since Python 3.9, now causes a DeprecationWarning to be emitted when it is used.

urllib: urllib.parse.Quoter is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168 [https://github.com/python/cpython/issues/88168].)

Pending removal in Python 3.15

The import system:

Setting __cached__ on a module while failing to set __spec__.cached is deprecated. In Python 3.15, __cached__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

Setting __package__ on a module while failing to set __spec__.parent is deprecated. In Python 3.15, __package__ will cease to be set or take into consideration by the import system or standard library. (gh-97879 [https://github.com/python/cpython/issues/97879])

ctypes:

The undocumented ctypes.SetPointerType() function has been deprecated since Python 3.13.

http.server:

The obsolete and rarely used CGIHTTPRequestHandler has been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.

The --cgi flag to the python -m http.server command-line interface has been deprecated since Python 3.13.

locale:

The getdefaultlocale() function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817 [https://github.com/python/cpython/issues/90817]), but has been postponed to Python 3.15. Use getlocale(), setlocale(), and getencoding() instead. (Contributed by Hugo van Kemenade in gh-111187 [https://github.com/python/cpython/issues/111187].)

pathlib:

PurePath.is_reserved() has been deprecated since Python 3.13. Use os.path.isreserved() to detect reserved paths on Windows.

platform:

java_ver() has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.

threading:

RLock() will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.

types:

types.CodeType: Accessing co_lnotab was deprecated in PEP 626 [https://peps.python.org/pep-0626/] since 3.10 and was planned to be removed in 3.12, but it only got a proper DeprecationWarning in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in gh-101866 [https://github.com/python/cpython/issues/101866].)

typing:

The undocumented keyword argument syntax for creating NamedTuple classes (for example, Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.

The typing.no_type_check_decorator() decorator function has been deprecated since Python 3.13. After eight years in the typing module, it has yet to be supported by any major type checker.

wave:

The getmark(), setmark(), and getmarkers() methods of the Wave_read and Wave_write classes have been deprecated since Python 3.13.

Pending removal in Python 3.16

The import system:

Setting __loader__ on a module while failing to set __spec__.loader is deprecated. In Python 3.16, __loader__ will cease to be set or taken into consideration by the import system or the standard library.

array:

The 'u' format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the 'w' format code (Py_UCS4) for Unicode characters instead.

asyncio:

asyncio.iscoroutinefunction() is deprecated and will be removed in Python 3.16, use inspect.iscoroutinefunction() instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875 [https://github.com/python/cpython/issues/122875].)

builtins:

Bitwise inversion on boolean types, ~True or ~False has been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2 and -1). Use not x instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to int explicitly (~int(x)).

shutil:

The ExecError exception has been deprecated since Python 3.14. It has not been used by any function in shutil since Python 3.4, and is now an alias of RuntimeError.

symtable:

The Class.get_methods method has been deprecated since Python 3.14.

sys:

The _enablelegacywindowsfsencoding() function has been deprecated since Python 3.13. Use the PYTHONLEGACYWINDOWSFSENCODING environment variable instead.

tarfile:

The undocumented and unused TarFile.tarfile attribute has been deprecated since Python 3.13.

Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

argparse:

Nesting argument groups and nesting mutually exclusive groups are deprecated.

Passing the undocumented keyword argument prefix_chars to add_argument_group() is now deprecated.

The argparse.FileType type converter is deprecated.

array’s 'u' format code (gh-57281 [https://github.com/python/cpython/issues/57281])

builtins:

bool(NotImplemented).

Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.

Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords and, else, for, if, in, is and or. In a future release it will be changed to a syntax error. (gh-87999 [https://github.com/python/cpython/issues/87999])

Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of int.

Support for __float__() method returning a strict subclass of float: these methods will be required to return an instance of float.

Support for __complex__() method returning a strict subclass of complex: these methods will be required to return an instance of complex.

Delegation of int() to __trunc__() method.

Passing a complex number as the real or imag argument in the complex() constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218 [https://github.com/python/cpython/issues/109218].)

calendar: calendar.January and calendar.February constants are deprecated and replaced by calendar.JANUARY and calendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636 [https://github.com/python/cpython/issues/103636].)

codeobject.co_lnotab: use the codeobject.co_lines() method instead.

datetime:

utcnow(): use datetime.datetime.now(tz=datetime.UTC).

utcfromtimestamp(): use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).

gettext: Plural value must be an integer.

importlib:

load_module() method: use exec_module() instead.

cache_from_source() debug_override parameter is deprecated: use the optimization parameter instead.

importlib.metadata:

EntryPoints tuple interface.

Implicit None on return values.

logging: the warn() method has been deprecated since Python 3.3, use warning() instead.

mailbox: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

os: Calling os.register_at_fork() in multi-threaded process.

pydoc.ErrorDuringImport: A tuple value for exc_info parameter is deprecated, use an exception instance.

re: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760 [https://github.com/python/cpython/issues/91760].)

sre_compile, sre_constants and sre_parse modules.

shutil: rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

ssl options and protocols:

ssl.SSLContext without protocol argument is deprecated.

ssl.SSLContext: set_npn_protocols() and selected_npn_protocol() are deprecated: use ALPN instead.

ssl.OP_NO_SSL* options

ssl.OP_NO_TLS* options

ssl.PROTOCOL_SSLv3

ssl.PROTOCOL_TLS

ssl.PROTOCOL_TLSv1

ssl.PROTOCOL_TLSv1_1

ssl.PROTOCOL_TLSv1_2

ssl.TLSVersion.SSLv3

ssl.TLSVersion.TLSv1

ssl.TLSVersion.TLSv1_1

sysconfig.is_python_build() check_home parameter is deprecated and ignored.

threading methods:

threading.Condition.notifyAll(): use notify_all().

threading.Event.isSet(): use is_set().

threading.Thread.isDaemon(), threading.Thread.setDaemon(): use threading.Thread.daemon attribute.

threading.Thread.getName(), threading.Thread.setName(): use threading.Thread.name attribute.

threading.currentThread(): use threading.current_thread().

threading.activeCount(): use threading.active_count().

typing.Text (gh-92332 [https://github.com/python/cpython/issues/92332]).

unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.

urllib.parse deprecated functions: urlparse() instead

splitattr()

splithost()

splitnport()

splitpasswd()

splitport()

splitquery()

splittag()

splittype()

splituser()

splitvalue()

to_bytes()

wsgiref: SimpleHandler.stdout.write() should not do partial writes.

xml.etree.ElementTree: Testing the truth value of an Element is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.

zipimport.zipimporter.load_module() is deprecated: use exec_module() instead.

파이썬 모듈 배포하기

참고

Information and guidance on distributing Python modules and packages has been moved to the Python Packaging User Guide [https://packaging.python.org/], and the tutorial on packaging Python projects [https://packaging.python.org/en/latest/tutorials/packaging-projects/].

인자 클리닉 How-To

참고

The Argument Clinic How-TO has been moved to the Python Developer’s Guide [https://devguide.python.org/development-tools/clinic/].

How to port Python 2 Code to Python 3

저자:

Brett Cannon

Python 2 reached its official end-of-life at the start of 2020. This means that no new bug reports, fixes, or changes will be made to Python 2 - it’s no longer supported: see PEP 373 [https://peps.python.org/pep-0373/] and status of Python versions [https://devguide.python.org/versions].

순수 파이썬 코드 대신 확장 모듈을 이식하려고 한다면 확장 모듈을 파이썬 3에 이식하기를 참조하십시오.

The archived python-porting [https://mail.python.org/pipermail/python-porting/] mailing list may contain some useful guidance.

Since Python 3.11 the original porting guide was discontinued. You can find the old guide in the archive [https://docs.python.org/3.10/howto/pyporting.html].

Third-party guides

There are also multiple third-party guides that might be useful:

Guide by Fedora [https://portingguide.readthedocs.io]

PyCon 2020 tutorial [https://www.youtube.com/watch?v=JgIgEjASOlk]

Guide by DigitalOcean [https://www.digitalocean.com/community/tutorials/how-to-port-python-2-code-to-python-3]

Guide by ActiveState [https://www.activestate.com/blog/how-to-migrate-python-2-applications-to-python-3]

aifc — Read and write AIFF and AIFC files

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the aifc module was Python 3.12 [https://docs.python.org/3.12/library/aifc.html].

asynchat — Asynchronous socket command/response handler

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library. It was removed in Python 3.12 after being deprecated in Python 3.6. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Applications should use the asyncio module instead.

The last version of Python that provided the asynchat module was Python 3.11 [https://docs.python.org/3.11/library/asynchat.html].

asyncore — Asynchronous socket handler

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library. It was removed in Python 3.12 after being deprecated in Python 3.6. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Applications should use the asyncio module instead.

The last version of Python that provided the asyncore module was Python 3.11 [https://docs.python.org/3.11/library/asyncore.html].

audioop — Manipulate raw audio data

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the audioop module was Python 3.12 [https://docs.python.org/3.12/library/audioop.html].

cgi — Common Gateway Interface support

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

A fork of the module on PyPI can be used instead: legacy-cgi [https://pypi.org/project/legacy-cgi/]. This is a copy of the cgi module, no longer maintained or supported by the core Python team.

The last version of Python that provided the cgi module was Python 3.12 [https://docs.python.org/3.12/library/cgi.html].

cgitb — Traceback manager for CGI scripts

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

A fork of the module on PyPI can now be used instead: legacy-cgi [https://pypi.org/project/legacy-cgi/]. This is a copy of the cgi module, no longer maintained or supported by the core Python team.

The last version of Python that provided the cgitb module was Python 3.12 [https://docs.python.org/3.12/library/cgitb.html].

chunk — Read IFF chunked data

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the chunk module was Python 3.12 [https://docs.python.org/3.12/library/chunk.html].

crypt — Function to check Unix passwords

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Applications can use the hashlib module from the standard library. Other possible replacements are third-party libraries from PyPI: legacycrypt [https://pypi.org/project/legacycrypt/], bcrypt [https://pypi.org/project/bcrypt/], argon2-cffi [https://pypi.org/project/argon2-cffi/], or passlib [https://pypi.org/project/passlib/]. These are not supported or maintained by the Python core team.

The last version of Python that provided the crypt module was Python 3.12 [https://docs.python.org/3.12/library/crypt.html].

distutils — Building and installing Python modules

Deprecated since version 3.10, removed in version 3.12.

This module is no longer part of the Python standard library. It was removed in Python 3.12 after being deprecated in Python 3.10. The removal was decided in PEP 632 [https://peps.python.org/pep-0632/], which has migration advice [https://peps.python.org/pep-0632/#migration-advice].

The last version of Python that provided the distutils module was Python 3.11 [https://docs.python.org/3.11/library/distutils.html].

imghdr — Determine the type of an image

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Possible replacements are third-party libraries from PyPI: filetype [https://pypi.org/project/filetype/], puremagic [https://pypi.org/project/puremagic/], or python-magic [https://pypi.org/project/python-magic/]. These are not supported or maintained by the Python core team.

The last version of Python that provided the imghdr module was Python 3.12 [https://docs.python.org/3.12/library/imghdr.html].

imp — Access the import internals

Deprecated since version 3.4, removed in version 3.12.

This module is no longer part of the Python standard library. It was removed in Python 3.12 after being deprecated in Python 3.4.

The removal notice includes guidance for migrating code from imp to importlib.

The last version of Python that provided the imp module was Python 3.11 [https://docs.python.org/3.11/library/imp.html].

mailcap — Mailcap file handling

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the mailcap module was Python 3.12 [https://docs.python.org/3.12/library/mailcap.html].

msilib — Read and write Microsoft Installer files

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the msilib module was Python 3.12 [https://docs.python.org/3.12/library/msilib.html].

nis — Interface to Sun’s NIS (Yellow Pages)

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the nis module was Python 3.12 [https://docs.python.org/3.12/library/nis.html].

nntplib — NNTP protocol client

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the nntplib module was Python 3.12 [https://docs.python.org/3.12/library/nntplib.html].

ossaudiodev — Access to OSS-compatible audio devices

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the ossaudiodev module was Python 3.12 [https://docs.python.org/3.12/library/ossaudiodev.html].

pipes — Interface to shell pipelines

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Applications should use the subprocess module instead.

The last version of Python that provided the pipes module was Python 3.12 [https://docs.python.org/3.12/library/pipes.html].

smtpd — SMTP Server

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library. It was removed in Python 3.12 after being deprecated in Python 3.6. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

A possible replacement is the third-party aiosmtpd [https://pypi.org/project/aiosmtpd/] library. This library is not maintained or supported by the Python core team.

The last version of Python that provided the smtpd module was Python 3.11 [https://docs.python.org/3.11/library/smtpd.html].

sndhdr — Determine type of sound file

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Possible replacements are third-party modules from PyPI: filetype [https://pypi.org/project/filetype/], puremagic [https://pypi.org/project/puremagic/], or python-magic [https://pypi.org/project/python-magic/]. These are not supported or maintained by the Python core team.

The last version of Python that provided the sndhdr module was Python 3.12 [https://docs.python.org/3.12/library/sndhdr.html].

spwd — The shadow password database

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

A possible replacement is the third-party library python-pam [https://pypi.org/project/python-pam/]. This library is not supported or maintained by the Python core team.

The last version of Python that provided the spwd module was Python 3.12 [https://docs.python.org/3.12/library/spwd.html].

sunau — Read and write Sun AU files

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the sunau module was Python 3.12 [https://docs.python.org/3.12/library/sunau.html].

telnetlib — Telnet client

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

Possible replacements are third-party libraries from PyPI: telnetlib3 [https://pypi.org/project/telnetlib3/] or Exscript [https://pypi.org/project/Exscript/]. These are not supported or maintained by the Python core team.

The last version of Python that provided the telnetlib module was Python 3.12 [https://docs.python.org/3.12/library/telnetlib.html].

uu — Encode and decode uuencode files

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the uu module was Python 3.12 [https://docs.python.org/3.12/library/uu.html].

xdrlib — Encode and decode XDR data

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library. It was removed in Python 3.13 after being deprecated in Python 3.11. The removal was decided in PEP 594 [https://peps.python.org/pep-0594/].

The last version of Python that provided the xdrlib module was Python 3.12 [https://docs.python.org/3.12/library/xdrlib.html].